3.3: Grain Harvest and Handling
Tim Stombaugh
Biosystems and Agricultural Engineering
University of Kentucky
Lexington, Kentucky, USA
| Key Terms |
| Performance | Efficiency | Dissociation |
| Productivity | Functional processes | Separation |
| Quality | Engagement | Transport |
Variables
Note about units: In this list of variables, dimensions of variables are given. In the text, variable definitions include dimensions as well as example SI units for illustration.
Introduction
One unique skill that biosystems engineers must develop is the ability to understand how mechanical systems interact with biological systems. This interaction is very prevalent in the design of machinery and systems for harvesting grains such as corn (maize, Zea mays ), soybean ( Glycine max ), wheat ( Triticum ), or canola ( Brassica napus ). The machines must traverse through a field on a biologically active soil to engage the plants growing in that field. The variability in plant and soil properties (e.g., maturity, moisture content, and structural integrity) within a field can be extensive. This variability presents a challenge to design engineers to conceive machines that can accommodate this variability and provide the machine operator with the flexibility needed to properly engage the plants. The goal of this chapter is to lay the engineering foundation needed to design machinery systems for harvesting grain crops.
Concepts
One key to becoming a great engineer is the ability to identify and understand the core problem to be solved. Too often, engineers focus on improving current solutions to problems rather than looking for better solutions. In the case of grain harvest, the engineer might be tempted to focus on ways to improve the grain combine (Figure 3.3.1), which is the machine most commonly used to harvest grain. The most unique and creative engineering solutions will often come only when the engineer focuses on identifying the fundamental problem to be solved.
With grain harvest, the core challenge is to recover a certain fraction or fractions of the plants in a grain crop that is grown in large fields. The fraction that is to be retrieved may vary by plant and by situation. In corn (maize, Zea mays ) harvest, for example, the most commonly harvested plant fraction is the kernel, which is used in a variety of products including food, sugar, and biofuel production. For fresh market sweet corn harvest, the whole ear is recovered with the husks intact. In some animal production systems, the whole ear without husks is recovered for animal feed; in other animal production systems, the entire plant is harvested and ensiled for feed. In these examples, the maturity and moisture content of the plant material may be drastically different if the corn is being recovered for sugar production, animal feed, or human consumption. A further challenge may exist where multiple plant fractions are harvested for different purposes. In industrial hemp (cannabis) production, for example, the seeds of the plant might be recovered for oil or food production, and the plant stems might be recovered separately for fiber production. The plurality of production streams will not be independent of each other and must be considered in the design of the mechanization solution. This chapter focuses on systems where only the grain is recovered.
Performance
The performance of a grain harvesting machine or system can be measured using three general metrics: productivity, quality, and efficiency.
Productivity
The productivity of a harvesting machine or operation is a measure of how much useful work is accomplished. As described in ASABE Standard EP496.3 (2015a), it can be quantified using two primary metrics. First, it can be measured on an area basis indicating how much of the area of a field was covered per unit time. This metric is expressed as the effective field capacity ( C a ) and can be calculated as:
\[ C_{a}=swE_{f} \]
where C a = effective field capacity in area per unit time (m 2 h −1 )
s = field speed in distance per unit time (m h −1 )
w = machine width (m)
E f = field efficiency (decimal)
Second, productivity can be measured on a material basis indicating how much of the grain is recovered per unit time. Material capacity ( C m ) is related to the area capacity by:
\[ C_{m}=C_{a}y \]
where C m = material capacity in weight or volume per unit time (m 3 h −1 )
y a = recovered (harvested) crop yield in weight or volume per unit area (m 3 m −2 )
| Commodity |
Moisture Content
(%) |
Weight
(lb/bushel) |
Weight
(kg/bushel) |
|---|---|---|---|
|
Corn (Zea mays) |
15.5 |
56 |
25.40 |
|
Soybean (Glycine max) |
13 |
60 |
27.22 |
|
Sunflower (Helianthus annuus) |
10 |
100 |
45.36 |
|
Wheat (Triticum aestivum) |
13.5 |
60 |
27.22 |
Material capacity can be reported on either a volume or mass basis with appropriate density conversion. In international trade, grain quantity is typically reported in metric tons. In U.S. grain production, grain quantity is commonly measured using units of bushels. While a bushel is technically a volume measurement equaling 35.239 L, in grain production it is a unit that reflects a standardized weight of grain at a particular moisture content specified for that grain. The standardized weights of a grain bushel for some common crops are listed in Table 3.3.1.
Quality
The second measure of performance of a mechanized grain harvest system is product quality. Ideally, the product (grain) that is recovered is free from any foreign matter and damage, but this is rarely the case. Small pieces of plant material and other foreign matter are often captured with the grain. The machinery can also cause physical damage to the grains as they pass through the different mechanisms. Machine design, as well as crop and operating conditions, can have an effect on foreign matter and damage, which are often referred to collectively as dockage. The term dockage is used because producers generally incur a financial penalty (docked some amount) from the market value of the grain by the buyer if the grain is damaged, contains excessive foreign matter, or is not at the proper moisture content.
Efficiency
The third measure of performance, efficiency, can be quantified in two ways. The first is a time-based field efficiency ( E f ) that relates the actual time required to complete a field operation to the theoretical completion time had there been no delays, such as turning around at the ends of the field, machine repair, and operator breaks. Field efficiency is calculated as:
\[ E_{f} = \frac{T_{t}}{T_{a}} \]
where T t = theoretical completion time
T a = actual completion time
Efficiency can also be measured based on the completeness of the harvest operation. This harvest efficiency ( E h ) is a measure of the amount of desirable product that is actually recovered relative to the amount of product that was originally available to the harvesting machine. It is calculated as:
\[ E_{h} = \frac{y_{a}}{y_{p}} \]
where y a = actual yield of grain recovered measured in weight per unit area (kg m −2 )
y p = potential yield of grain in the field measured in weight per unit area (kg m −2 )
The antithesis of harvest efficiency is harvest loss ( L h ), which is the amount of grain lost by the harvesting machine per unit area expressed as a percentage of the potential yield. It can be calculated as:
\[ L_{h} = 1-E_{h} \]
When focusing on the harvesting operation, the potential yield of the crop is considered to be the harvestable grain that is still attached to the plants. Potential yield does not consider the grains that have fallen from the plants before the machine engages them. If harvest is delayed after the optimum time, potential yield will often decrease due to natural forces causing seeds to fall from the plants. This pre-harvest yield loss ( y ph ) is the amount of grain that is lost before harvest expressed on a per area basis. It is the difference between the total yield that the plants actually produced ( y t ) and the potential harvestable yield:
\[ y_{ph} = y_{t}-y_{p} \]
There are often strong interrelationships between productivity, grain quality, and efficiency of grain harvest. For example, an increase in productivity could be realized by an increase in speed or field efficiency; however, grain quality and harvest efficiency may be compromised. Finding the fiscally optimum operation point is a challenge to be addressed by both the design engineer and the machine operator. The engineer must understand the needs of the operator and incorporate the appropriate flexibility of control into the design of the machine.
Functional Processes
When considering the design of any mechanization system, the engineer should first carefully consider the potential processes that will have to be undertaken to complete the task. Srivastava et al. (2006) expand on a number functional process that could occur in grain harvest. These processes can be simplified to four main processes:
- • Engage the crop to establish mechanical control of the grain.
- • Dissociate or break the connection between the individual grains and the plant.
- • Separate the grain from all of the other plant material.
- • Transport the grain to the proper receiving facility.
Depending on the specific system, these functions could take place in varying order, and some processes may be repeated multiple times. Historically, before mobile grain combines were developed, a harvesting process involved gathering the whole plant from a field and transporting it to a central location where the grains were separated (threshed) from the plant material either by hand or with a stationary machine. With modern harvesting machines, the grain dissociation and separation is accomplished as the machine moves through the field, and the only material that is transported away from the field is the grain. Likewise, some functions may be accomplished multiple times. For instance, there are often several separation stages in a single machine, and the product might be transported multiple times between different mechanisms, temporary storage units, and transportation vehicles before reaching the final destination.
Engagement
The process of engaging the crop can occur in many different ways depending on the particular crop and machine configuration. Often there is some type of mechanism that will grasp or pull the standing crop toward the machine as it moves forward. The grasping mechanism could be mechanical, such as a rotating arm or chain, or it could involve other forces such as pneumatics or gravity. Engagement may include a cutting action that severs the part of the plant containing the grain from the rest of the plant. The grasping and cutting actions usually result in the material being caught on some surface where it can then be moved into the machine.
Dissociation
The dissociation function of a grain harvest process involves physically breaking the connection between the desired particle and the plant. The term threshing is often used to describe the dissociation function, but in some contexts, threshing could also include some separation and cleaning functions. The dissociation performance of a harvesting machine is quantified by the threshing loss, L th , which is the amount of grain that remains connected to the plants expressed as a percentage of the total amount of grain that was presented to the threshing mechanism.
Engineers designing mechanisms to dissociate grain need to understand the basic principles of tensile and bending failure. Most grains are attached to the plant by some kind of stem and/or connective tissue. The connective tissue can often be understood as a cylindrical bundle of connective tissue. Most dissociation mechanisms apply a tensile force, a bending force, or a combination of the two on the seed relative to the plant (Figure 3.3.2). The goal of the force application is to cause a failure of the connective tissue between the grain and the stem or plant. Failure will occur when the stress in the connective tissue exceeds its ultimate yield stress, which is the stress at which the material will break. Obviously, it is desirable for the dissociation failure to occur as close to the individual grain as possible so that there is no stem or other plant material captured with the grain.
Tensile failure is the mode where the grain is pulled straight away from the stem until the connection fails. The linear tensile force induces stress in the connective tissue that can be calculated by the following equation:
\[ \sigma_{t} = \frac{F_{t}}{A} \]
where σ t = tensile stress in the connective tissue measured in force per unit area (N m −2 )
F t = tensile force acting on connective tissue (N)
A = cross-sectional area of the connective tissue (m 2 )
Bending failure occurs when the grain is rotated relative to the stem inducing bending stress in the connective tissue. Bending force or moment ( M ) can also be thought of as a rotational torque applied to the grain. Bending stress is described by the following equation:
\[ \sigma_{b} = \frac{M_{y}}{I} \]
where σ b = bending stress in the connective tissue measured in force per unit area (N m −2 )
M = bending force acting on the connective tissue measured in force × distance (N m)
y = perpendicular distance to neutral axis (m)
I = area moment of inertia of the connective tissue cross section in units of length to the fourth power (m 4 )
The moment of inertia is a quantity that is based on the shape of the cross section of the member and is used to characterize the member’s ability to resist bending.
Bending stress is a bit more complicated than tensile stress because the stress in the member is not constant across its cross section. Fibers farther from the neutral axis of bending will experience higher stress, which can actually enhance dissociation.
One of the challenges with describing failure of plant materials mathematically is the wide variability that can occur. The strength of the connective tissue is affected by three main factors based on biological properties of the plant. The first factor is plant size. Some plants within a single crop may grow larger than others and may have more connective tissue between the stem and grain. This would correspond to larger area and moment of inertia in Equations 3.3.7 and 3.3.8, which would require more force to reach the ultimate stress.
The second factor affecting connective tissue strength is plant maturity. Most plants will lose their grains naturally when they reach maturity as a mechanism for propagation. Mathematically, this natural dissociation is described by a reduction in the yield strength of the connective tissue. Quite often, this natural maturity state corresponds with the optimum time for grain harvest; however, it is not always possible to harvest at that exact time. Therefore, the failure strength could vary significantly based on actual harvest time.
The third factor affecting the strength of the connective tissue is moisture content. The strength properties of plant material vary greatly with moisture content. Engineers need to understand a number of biological properties of the plant as they are affected by moisture content. For instance, the turgor pressure in a plant is the pressure exerted on the walls of the cells within the plant by the moisture in the cells. As turgor pressure decreases, which is caused by a reduction in moisture content, plants become less rigid. In some plants, this might weaken the plant structure, making dissociation easier, but in others it could make it more difficult to dissociate a grain because the plant material would be more elastic. Depending on weather conditions and solar intensity, turgor pressure can vary greatly throughout a single day, affecting the dissociation of the crop.
Further complicating the mathematical representation of plant strength is the fact that there can be significant variability of plant size, maturity, and moisture content between different regions of a field, between different plants, and even between different grains on a single plant. Engineers need to develop mechanisms that accommodate this variability and give machine operators the flexibility to adapt the machine to the various conditions.
Separation
Once the grains are dissociated from the plant, they must be separated from the rest of the plant material and any other undesirable material. This undesirable material is called material other than grain (MOG). The separation performance of a harvesting machine is quantified by the separation loss ( L s ), which is the amount of free grain that cannot be separated from the MOG expressed as a percentage of the total amount of grain that was dissociated from the plants by the machine.
There are two main principles that are typically used to separate grain from MOG. The first is mechanical separation through sieving. A sieve is simply a barrier with holes of a correct size that allows the desired particles to pass through while preventing larger particles from passing, or vice versa, allow smaller undesirable particles to pass through while retaining the desired particles. Some grain sieving mechanisms rely on gravitational forces on the particles to cause them to pass downward through the sieve openings; others utilize centripetal forces of rotating mechanisms to force particles outward through the sieves. Most gravitational sieving mechanisms induce a shaking or bouncing motion on the material to enhance the separation process by facilitating particle motion downward through the mat of material as well as causing motion of the material across the sieve.
Consider the sieve plate connected to the parallel rotating bars as shown in Figure 3.3.3.  The sieve plate moves in a circular pattern while maintaining its horizontal orientation. If the design of the length of the rotating arms along with the rotational speed is correct, the material is bounced laterally across the plate. As it bounces, the grains move downward through the mat of material, then through appropriately-sized holes in the plate. The MOG travels across the plate and is deposited off the end of the sieve.
The velocity of the sieve plate ( v ) can be calculated from the following equation:
\[ v = r\omega \]
where v = velocity of the sieve plate (m s −1 )
r = length of the rotating support, or connecting, arms (m)
ω = rotational speed of the arms (radians s −1 )
The velocity of the sieve plate is actually the tangential velocity of the rotating support arms. The direction of this velocity changes sinusoidally as the bars rotate. The vertical ( v v ) and horizontal ( v h ) components of the velocity can be described with the following equations:
\[ v_{v} = v\ cos\theta \]
where θ = the angular position of the arms.
The bouncing motion of a particle is analyzed by considering the momentum of the particle in relation to the upward moving, but decelerating, plate to determine if and when the particle will leave the plate.
The second principle that is used to separate grains from MOG is aerodynamic separation. Quite often, the grain particles are denser and have significantly different aerodynamic properties than the MOG, especially the lighter leaf and hull particles. These differences are exploited to separate the MOG from the grain.
A particle that is moving through any fluid, including air, is subjected to gravity and drag forces (Figure 3.3.4). Gravity acts downward on the particle and produces the force represented by:
\[ F_{g} = mg \]
where F g = gravitational force (N, or m kg s −2 )
m = mass of the particle (kg)
g = gravitational constant in units of length per unit time squared (9.81 m s −2 )
The drag force acts in the opposite direction of the particle’s motion relative to the air. The drag force is calculated by:
\[ F_{d} = 0.5\rho_{air}v^{2}_{part}C_{d}A_{part} \]
where F d = drag force (N, or m kg s −2 )
ρ air = density of the air in units of mass per unit of volume (kg m −3 )
v part = velocity of the particle relative to the air in units of length per time (m s −1 )
C d = unitless drag coefficient of the particle
A part = characteristic area of the particle (m 2 ).
The motion of the particle is determined by the vector sum of the two forces and the fundamental motion equation:
\[ a = \frac{F_{r}}{m} \]
where a = acceleration of the particle in the direction of the resultant force (m s −2 )
F r = resultant force on the particle (N, or m kg s −2 )
The particle trajectory can be described mathematically by integrating the acceleration equation once to get the velocity equation, then a second time to find position as a function of time.
The drag coefficient is a function of many particle factors including its shape and surface texture. Many MOG particles, such as seed hulls and stem particles, have a more irregular shape and surface texture than the grains and, thus, will have a higher drag coefficient. Aerodynamic separation occurs by capitalizing on these drag differences as well as differences in mass between the grain and MOG particles. Particles can be separated if an air stream is directed through the mat of grain and MOG in such a manner that the MOG is directed in a different trajectory than the grains.
Consider an air stream created by a fan blowing straight upward at a falling particle. If the air speed is increased to the point that the drag force equals the gravity force, the particle will be suspended in the air stream. The velocity of the air at this point is, by definition, the terminal velocity of the particle. If the air speed is increased, the particle will move upward; if the air speed is decreased, the particle will move downward.
Consider a mixture of grain and MOG particles being dropped through a directed air stream as illustrated in Figure 3.3.4. If the air velocity is set slightly below the terminal velocity of the grains, their trajectory will be altered to the right somewhat, but they will continue to move downward. MOG particles that have a much higher drag force and correspondingly lower terminal velocity will be carried more upward and to the right by the air stream moving them out of the grain flow.
Transport
Once the grain is dissociated and separated from the MOG, it must be transported to a receiving station. This is usually accomplished in several steps or stages using a variety of mechanisms. Various types of conveyors are used to move the grain from one part of a machine to another or from one machine to another. At different stages of the process, the grain might be stored or carried in various bulk containers.
The principles involved with designing or analyzing bulk storage or transportation containers are primarily strength of materials. The designer first needs to determine what forces will be produced on the structure by the grain. Free body diagrams are analyzed to determine the magnitude and direction of all forces. One challenge in designing grain harvesting machinery is that the machines are often mobile. As the machines move across the rough terrain typically encountered in agricultural fields, dynamic forces are induced as the grain load bounces. Designers typically utilize a variety of techniques to predict the maximum dynamic loads that could be induced on a structure.
Once the forces are known, the designer then determines what stresses are induced in each structural member by the grain load. Stress ( σ ) describes the amount of force ( F ) being carried per unit area ( A ) of a given structural member:
\[ \sigma = \frac{F}{A} \]
where σ = stress in units of force per unit area (N m −2 )
F = force in the member (N)
A = characteristic area of the member (m 2 )
The stress in any part of a structural member cannot exceed the yield stress of the material or permanent damage (deformation) will be incurred. But even if permanent deformation is not induced in a structural member, engineers still need to be concerned about how much a structural member flexes or deflects. The deflection in a member is calculated from strain, which is:
\[ \epsilon = \frac{dL}{L} = \frac{\sigma}{E} \]
where ε = strain (dimensionless)
L = length of the member (m)
E = modulus of elasticity reported in force per unit area (N m −2 )
Stress and strain are related by the modulus of elasticity, also known as Young’s modulus. The lower the modulus of elasticity, the more deflection a given force will cause in a member. Some deflection can be good in a structure, especially when dynamic forces are involved, because it helps to absorb energy without causing high peak loads. In the case of a machine moving across a rough field, for example, some deflection in the structure can absorb some of the energy caused by uneven terrain and prevent structural failure.
For shorter distance transportation, several different conveying devices can be employed. When designing conveying devices, the designer is primarily concerned about the capacity of the device and the power required to convey the material. Some of the simplest conveying devices utilize paddles or buckets connected to chains (Figure 3.3.5) to drag or convey the grain. The capacity of paddle conveyors, which is the flow rate of material through the conveyor, is calculated simply by the amount of material carried by each paddle and the number of paddles that pass a point in a given amount of time:
\[ Q_{a} = Vn \]
where Q a = actual flowrate in volume per unit time (m 3 s −1 )
V = volume of material carried by a single paddle (m 3 )
n = number of paddles that are discharged per unit time (s −1 )
The volume of material that can be carried by the paddles is affected by a number of parameters. Grain properties such as particle shape, size, surface friction and moisture content affect the shape of the pile of grain on each paddle. The slope of the conveyor limits the size of the piles before the grain runs over the top of the paddle and back down the conveyor.
Another conveying device commonly used in grain harvest and handling is a screw conveyor, commonly known as an auger (Figure 3.3.6).  The capacity of a horizontal screw conveyor that is completely full of grain is the volume displaced by a single rotation of the shaft times the number of rotations in a given unit of time, which can be calculated by:
\[ Q_{t}=\frac{\pi}{4} (D^{2}-d^{2})P\omega \]
where Q t = theoretical flowrate in volume per unit time (m 3 s −1 )
D = outside diameter of the flighting (m)
d = diameter of shaft (m)
P = pitch length of the flighting (m)
ω = rotational speed of the shaft (radians s −1 )
When the conveyor is inclined, the flighting will no longer be full as the grain will tend to slide down around the flighting. The actual volumetric flowrate ( Q a ) can be calculated by:
\[ Q_{a}= Q_{t} \eta_{v} \]
where η v is the volumetric efficiency of the conveyor. Predicting the volumetric efficiency can be very challenging because it is affected by numerous factors, including conveyor slope, rotational speed, grain moisture content, particle size, particle to conveyor friction, and particle-to-particle friction. Because of this complexity, mathematical prediction is usually accomplished with empirical relationships.
The power required to convey the material is affected by gravitational and friction forces. If the grain is lifted any vertical distance, the conveyor must overcome the gravitational force opposing that lift. Power is defined as a force applied over a given distance in a given amount of time (force × distance/time). The force and time components of the gravitational power calculation come from the flow rate of the grain through the conveyor expressed in units of weight per unit of time. The density of the grain can be used to convert volumetric flow rate into a weight flow rate. The distance component of power is simply the vertical distance that the grain is lifted. The gravimetric component of power is:
\[ P_{q} = Q_{a}\rho_{grain}h \]
where P g = power required to overcome gravity (W or J/s)
Q a = actual volumetric flow rate of grain (m 3 s −1 )
ρ grain = density of the grain (kg m −3 )
h = height that the material is lifted (m).
The friction component of power can be more complicated to compute. In the case of a paddle conveyor, the grain must be slid along the bottom of the conveyor surface. This friction force can sometimes be predicted quite well from the coefficient of friction between the grains and the surface of the conveyor. If that coefficient of friction gets too large, the forces due to friction on the grains at the interface between the grain pile and the conveyor surface will cause the grains within the pile to begin to move relative to each other. At this point, it becomes more difficult to mathematically describe the energy necessary to overcome these internal friction forces as well as the surface friction.
Frictional forces in screw conveyors are similar. The grain in a full horizontal conveyor slides along the outside wall of the conveyor tube as well as the flighting but does not move as much within the grain mass. As the conveyor is inclined and it is no longer completely full, the amount of motion within the grain mass increases and becomes more critical to the evaluation.
Applications
The most common machine used for grain harvest is the modern grain combine (Figure 3.3.1). Combines typically have an interchangeable attachment on the front called a header that engages the crop and passes certain fractions of that plant into the combine. The material then passes through a threshing mechanism that dissociates the grains from the plant stems and also performs some separation of grain from MOG. The grain and MOG are then passed through various separating and cleaning mechanisms. The MOG is generally passed longitudinally through the machine and expelled from the back. The clean grain generally moves downward through the machine to a catch reservoir on the bottom. From there, it is moved upward with paddle and/or screw conveyors to a holding tank on the top of the machine. A large screw conveyor is then used to periodically empty the contents of the holding tank into a truck or other vehicle, which transports the grain to a receiving station.
Engagement
Header attachments are used to engage the crop. The two most common types of header attachments on grain combines are the grain table and the corn or row head. Grain tables (Figure 3.3.1) are typically used in small grain crops such as wheat and soybean. They generally include a large gathering reel to engage the crop and pull it into the header. A cutting mechanism, typically a sickle bar, cuts the plant as it is pulled into the header to gain mechanical control of the grain. Since grain tables can be 12 m wide or wider, cross conveyors move the crop material from the ends of the header to the center where it is fed into the combine.
The height of the cut depends on the crop and the cultural practice of the operation. The threshing and separation processes in the combine are most efficient when the MOG entering the combine is minimized. In soybean, for example, the seed pods can grow very low on the plant stem; therefore, the crop must be cut near the ground to prevent losses. In crops like wheat where the grains grow in a head on the top of the plant stem, the cut height could be just low enough to capture the entire head but minimize the amount of MOG passed into the machine. In some production systems, though, the MOG might be used for animal bedding or bioenergy. In these cases, the header is operated lower so that more MOG is gathered, passed through the combine and deposited in a narrow line, called a windrow, behind the combine. The windrow can easily be gathered by another biomass harvesting machine in a separate operation. Occasionally, the MOG is gathered by another machine, such as a baler, attached directly to the combine (Figure 3.3.7).
In corn (maize), the grains are produced toward the middle of the plant. Cutting the plant to capture the ears for threshing would mean the introduction of large amounts of MOG into the harvest stream, hampering threshing and separation performance. Since corn is typically grown in rows spaced 0.5–0.75 m, corn heads are constructed with fingers that pass between the rows so that each row of corn can be engaged individually (Figure 3.3.8). Long parallel rollers on each side of the row grab the plant stems below the ear and pull them downward as the machine moves forward. Stripper plates above each roller are spaced such that the plants pass down between them, but the corn ears do not. As the plants are pulled downward, the ears are stripped off the plants. Ideally, all of the plant material is pulled down through the header and does not pass into the combine. Depending on stalk condition, some stalk breakage and leaf removal will occur, and that MOG will have to be separated in the combine. Chains with fingers above each stripper plate move the ears and MOG back into the header. Cross conveyors then move material from the edge of the header into the center where it is fed into the combine.
One of the performance measures of any header is its effectiveness in gathering all of the grain from the field into the combine. This engagement process is complicated by the fact that the grains tend to naturally fall off of the plants more easily when the crop is in its optimum harvest condition. Losses by the header are called shatter losses ( L sh ). They are quantified as a percentage of the potential yield ( y p ), i.e., the available yield of the plants.
Shatter losses are affected by crop conditions, including maturity and moisture content. They are also affected by the design and operation of the header. For example, the speed of the gathering reel on grain tables must be matched to the forward speed of the machine. If the reel speed is too high, the plants are beaten aggressively, causing grains to fall off the plants before they can be caught on the header platform. If the reel speed is too slow, the plants could be pushed forward, again knocking grains onto the ground before they enter the header. Depending on crop conditions, the tangential speed of the reel is typically operated at least 25–50% faster than the forward speed of the combine to pull the plants into the header. Some machines utilize sensors and electronic controls to automatically adjust the reel speed to match machine forward speed.
Dissociation
The dissociation function in combines is generally accomplished by rotating cylinders called threshing cylinders. There are two basic configurations of threshing cylinders, distinguished by the direction the material moves through the cylinder. Some cylinders are mounted with their axis of rotation horizontal and perpendicular to the longitudinal axis of the machine. The material enters from one side of the cylinder and exits the other (Figure 3.3.9). Bars oriented along the outside of the cylinder rub the plant material against the stationary housing around the outside of the cylinder, which is called the concave. The rubbing action affects the dissociation of the grain from the plants. Holes in the concave facilitate a sieving action to separate some of the grain from the longer plant material.
The other common threshing configuration has the rotating threshing cylinder mounted parallel to the longitudinal axis of the machine. Material enters the end of the cylinder and moves in a helical pattern around and past the cylinder (Figure 3.3.10). Similar concave structures around the cylinder provide resistance to the flow to induce the dissociation and separation functions.
Threshing effectiveness is measured by the percentage of grains that are dissociated from the plants, the percentage of grains that are damaged during the threshing process, and the amount of MOG break-up. Excess amounts of small MOG particles can hamper separation efficiency since they can be indistinguishable from grains in the separation process. Threshing efficiency and grain damage are affected by plant properties, the design of the cylinder and concaves, and operational adjustments. Machine operators often have real-time control of the cylinder speed as well as the clearance between the cylinder and concave.
Separation
There are two different types of separation systems used in grain combines that are generally associated with the two types of threshing devices. Laterally oriented threshing cylinders generally feed the material stream onto a vibrating separator platform commonly called a straw walker. The oscillating plate is essentially a sieve allowing the smaller particles, including the grains, to fall through the sieve as the MOG is moved back through the machine.
On combines with axially oriented threshing cylinders, the latter portion of the cylinder and concave accomplish initial separation. These rotary separators utilize centripetal forces to separate grains outward through concave openings.
Regardless of the initial separator configuration, most combines pass the grain stream captured from the threshing unit and initial separation unit through an additional multi-stage cleaning sieve. Pneumatic separation is also applied in these sieves to enhance separation of grain from MOG.
Transport
The cleaned grain stream is conveyed from the bottom of the combine to a holding tank on the top of the machine using a combination of paddle and screw conveyors. The holding tanks vary in size with the size of the machine. Depending on the crop and operating conditions, the combine tank could be filled in as little as 3–4 minutes. In some operations, the combine is driven to the edge of the field when the tank is full so that it can be emptied into a truck for transport to a receiving station. This is often considered an inefficient use of a very expensive harvesting machine. Productivity of the harvesting operation is maximized if the combine can be operated as close to continuously as possible.
Combines can be unloaded while they are harvesting if a receiving vehicle can be driven alongside the combine. Over-the-road trucks are not typically used for this operation because of their relatively small tires. Traction in potentially soft soil conditions limits their mobility. Also, there is a concern regarding compaction of the soil in the field. Heavy loads on small tires will compact the soil under the tires causing damage that will affect the performance of future crops in the field.
In-field transport of grain is often accomplished with a grain cart (Figure 3.3.11). Grain carts are large transport tanks typically pulled by large agricultural tractors. Both the cart and tractor will be equipped with large tires or tracks to reduce the pressure on the soil.
With the use of grain carts, a logistical challenge arises around the best way to get the grain away from the combine to keep it harvesting. Many operations use multiple combines in a field simultaneously. Managers must decide how many grain carts are needed, how big those carts need to be, and how many trucks are needed to get the grain away from the field. Operationally, vehicle scheduling is a challenge to anticipate which combines in a multiple combine fleet must be emptied so that they do not fill up and become unproductive.
Examples
Example \(\PageIndex{1}\)
Example 1: Combine harvest efficiency
Problem:
One way to evaluate the harvest efficiency of a combine is to measure losses that occur as a combine moves through the field. This can be done by physically gathering and counting or weighing the grains found at different locations in the combine’s operating space.
Consider the combine in Figure 3.3.12 that was stopped while harvesting a very uniform crop of wheat. Field measurements were taken at three different locations as shown. At each point, a 1 m square area was selected as a representative test area. At point A in front of the combine, all of the standing plants in the test area were carefully cut and hand harvested to determine how much grain was available in the field. After that, the grains that were laying on the ground in that test area were gathered and weighed. At point B, all of the grains found within the test area were gathered and weighed. At point C, which is beyond the discharge trajectory of material being expelled from the back of the combine when it was stopped, all of the grains were collected and weighed separately by those that were still attached to the plants and those that were free. The following are the data collected at each location.
-
Point A:
- 335 g unharvested grain
- 15 g free grains (grains laying on the ground)
-
Point B:
- 40 g free grain
-
Point C:
- 63 g free grain
- 14 g grain attached to plant
Determine the gathering, threshing, and separating efficiencies of this harvest operation.
Solution
The theoretical or potential yield, y p , of the crop is the harvestable grain that is still attached to the plants when the combine engages it. In this example, the potential yield is based on the unharvested seed at point A.
\( y_{p} = \frac{0.335 \text{ kg}}{\text{m}^{2}} \cdot \frac{10000 \text{ m}^{2}}{ \text{ha}} = \frac{3350 \text{ kg}}{\text{ha}} = \frac{3.35 \ T}{\text{ha}} \)
A simple unit conversion can be performed to convert the metric yield into common U.S. yield units of bu/acre as:
\( y_{p} = \frac{3350 \text{ kg}}{\text{ha}} \cdot \frac{1 \text{ bu}}{27.22 \text{ kg}} \cdot \frac{1 \text{ ha}}{ 2.47\text{ acre}} = \frac{49.8 \text{ bu}}{\text{ha}} \)
Note that the potential yield calculation does not consider the grains that had fallen from the plants before the machine engaged them. In this example, the pre-harvest yield loss, y ph , was:
\( y_{ph} = \frac{0.015 \text{ kg}}{\text{m}^{2}} \cdot \frac{10000 \text{ m}^{2}}{\text{ ha}} = \frac{150 \text{ kg}}{\text{ha}} \)
As a percentage of the total available grain, the pre-harvest yield loss was:
\( L_{ph} = \frac{150}{3350 + 150} \cdot 100 = 4.3 \text{%} \)
The grain that was collected at point B under the combine includes the shatter losses as well as the pre-harvest losses. The pre-harvest losses are subtracted from the total grain at point B to determine grain lost as the header engaged the crop. The shatter loss, L sh , is calculated as a percentage of the theoretical yield as follows:
\( L_{sh} = \frac{(40 \text{ g}-15 \text{ g})}{335 \text{ g}} \cdot 100 = 7.5 \text{%} \)
Threshing loss is a quantification of the grains that did not get dissociated from the plant. These grains are found at point C still attached to plant material. The threshing loss percentage is based on the total grain that actually enters the combine. In this example, the shatter loss is removed from the total available grain in calculating the threshing loss, L th , as follows:
\( L_{th} = \frac{14 \text{ g}}{(335 \text{ g}-25 \text{ g})} \cdot 100 = 4.5 \text{%} \)
The separation loss is threshed grain that is not removed from the MOG stream and is lost out the back of the combine. The free grain collected at point C includes the separation loss as well as the shatter and yield losses. Therefore, the loss due only to separation, L s , is:
\( L_{s} = \frac{(63 \text{ g} - 15 \text{ g} - 25 \text{ g})}{(335 \text{ g} - 25 \text{ g})} \cdot 100=7.4 \text{%} \)
The total harvest loss, L h , is based on all the grain lost by the combine, which would be:
\( L_{h} = \frac{63 \text{ g} + 24 \text{ g} - 15 \text{ g}}{335 \text{ g}} \cdot 100 = 19\text{%} \)
The actual harvested yield, y a , then, is:
\( y_{a} = \frac{3.35 \ T}{\text{ha}}- \frac{0.19(3.35 \ T)}{\text{ha}} = \frac{2.71 \ T}{\text{ha}} \)
The harvest efficiency is (Equation 3.3.6):
\( E_{h} = 1 -L_{h} = 1-0.19 = 0.81 \)
This can be verified by Equation 3.3.4:
\( E_{h} = \frac{y_{a}}{y_{t}} = \frac{2.71 \ T}{\text{ha}} \cdot \frac{\text{ha}}{3.35 \ T} = 0.81 \)
The prudent manager would scrutinize these harvest efficiency numbers to determine if improvements are merited. For wheat harvest, these losses would probably be considered quite large. The manager may consider adjustment and/or operational changes to the combine that might reduce harvest losses.
Example \(\PageIndex{2}\)
Example 2: Reel speed
Problem:
One of the causes of shatter loss with grain tables is improper speed of the reel. The designers of a grain table need to provide ample adjustability in the rotational speed of the reel so that the operator can compensate for crop conditions and forward speed. Specifically, the designer needs to determine the range of speeds that the design must be able to achieve. Consider the grain table in Figure 3.3.13 that has a 1.3 m diameter reel. Determine the range of reel speeds that the design must be able to achieve.
Solution
As mentioned earlier, the tangential speed of the engaging devices on the end of the reel should typically be 25–50% greater than the combine forward speed, v f . ASAE Standard D497.7 is a great resource for operating parameters of common agricultural machinery. Table 3.3.3 of that standard (reprinted in part as Table 3.3.2 of this chapter) indicates that the typical forward speed of a self-propelled combine ranges from 3.0 to 6.5 km/hr. The minimum rotational speed of the reel would occur with the reel tangential speed 25% greater than the slowest forward speed of 3.0 km/hr. Conversely, the maximum speed would occur at 150% of 6.5 km/hr. The tangential speed, v t , is calculated using Equation 3.3.9:
| Field Efficiency | Field Speed | |||||
|---|---|---|---|---|---|---|
| Harvesting Machine | Range % | Typical % | Range mph | Typical mph | Range km/h | Typical km/h |
|
Corn picker sheller |
60–75 |
65 |
2.0–4.0 |
2.5 |
3.0–6.5 |
4.0 |
|
Combine |
60–75 |
65 |
2.0–5.0 |
3.0 |
3.0–6.5 |
5.0 |
|
Combine (SP) |
65–80 |
70 |
2.0–5.0 |
3.0 |
3.0–6.5 |
5.0 |
|
Mower |
75–85 |
80 |
3.0–6.0 |
5.0 |
5.0–10.0 |
8.0 |
|
Mower (rotary) |
75–90 |
80 |
5.0–12.0 |
7.0 |
8.0–19.0 |
11.0 |
|
Mower-conditioner |
75–85 |
80 |
3.0–6.0 |
5.0 |
5.0–10.0 |
8.0 |
|
Mower-conditioner (rotary) |
75–90 |
80 |
5.0–12.0 |
7.0 |
8.0–19.0 |
11.0 |
|
Windrower (SP) |
70–85 |
80 |
3.0–8.0 |
5.0 |
5.0–13.0 |
8.0 |
|
Side delivery rake |
70–90 |
80 |
4.0–8.0 |
6.0 |
6.5–13.0 |
10.0 |
|
Rectangular baler |
60–85 |
75 |
2.5–6.0 |
4.0 |
4.0–10.0 |
6.5 |
|
Large rectangular baler |
70–90 |
80 |
4.0–8.0 |
5.0 |
6.5–13.0 |
8.0 |
|
Large round baler |
55–75 |
65 |
3.0–8.0 |
5.0 |
5.0–13.0 |
8.0 |
|
Forage harvester |
60–85 |
70 |
1.5–5.0 |
3.0 |
2.5–8.0 |
5.0 |
|
Forage harvester (SP) |
60–85 |
70 |
1.5–6.0 |
3.5 |
2.5–10.0 |
5.5 |
|
Sugar beet harvester |
50–70 |
60 |
4.0–6.0 |
5.0 |
6.5–10.0 |
8.0 |
|
Potato harvester |
55–70 |
60 |
1.5–4.0 |
2.5 |
2.5–6.5 |
4.0 |
|
Cotton picker (SP) |
60–75 |
70 |
2.0–4.0 |
3.0 |
3.0–6.0 |
4.5 |
\( v_{t} = r \omega \)
At the minimum rotational speed, the tangential speed should be:
\( v_{t} = v_{f}(1.25) \)
Combining the equations, the minimum rotational speed is:
\( \omega = \frac{v_{t}}{r} = \frac{v_{f}(1.25)}{r} = \frac{3 \text{ km}}{\text{hr}} \cdot \frac{1.25}{1} \cdot \frac{2}{1.3 \ m} \cdot \frac{1000 \ m}{\text{km}} \cdot \frac{1 \text{hr}}{60 \text{ mins}} \cdot \frac{1 \text{hr}}{2\pi} = 15.4 \ \text{rpm} \)
It follows, then, that the maximum rotational speed is:
\( \omega =\frac{v_{t}}{r}=\frac{6 \text{ km}}{\text{ hr}}\cdot \frac{1.5}{1} \cdot \frac{2}{1.3 \ m} \cdot \frac{1000 \ m}{\text{km}}\cdot \frac{1 \ hr}{60 \text{ min}} \cdot \frac{1 \text{ rev}}{2\pi} = 36.7 \ rmp \)
The revolution units are added to the calculations by noting that radians are considered unitless, and there are 2π radians in one complete revolution. The conclusion is that the drive system for the reel on that grain table must be able to achieve speeds varying from 15.4 to 36.7 rpm, so the drive mechanism for the reel should be designed accordingly.
Example \(\PageIndex{3}\)
Example 3: Axle loads
Problem:
The design of the structure of a vehicle relies heavily on understanding the effects of all the forces on the machine. Consider a two-wheeled grain cart pulled by a tractor as shown in Figure 3.3.14. The task is to calculate the required size (diameter) of the cylindrical axles to support the cart wheel assembly. Assume that the grain load is evenly distributed in the tank of the cart and that the tank is laterally symmetrical, which means that the loads are evenly distributed between the left and right wheels of the cart. Besides the dimensions shown in Figure 3.3.15, the following data are given by a manufacturer for a very similar cart:
- Cart capacity: 850 bushels of corn (maize)
- Empty cart weight: 54 kN
- Tongue weight of empty cart: 11 kN
Solution
Because of the left/right symmetry of the cart, the free body analysis can be conducted in two dimensions looking at the side of the machine (Figure 3.3.15). The two cart wheels will have identical loads. Since the tractor supports 11 kN of the empty cart weight from the tongue at the hitch point ( F ct ), the rest of the empty cart weight, which is 54 kN – 11 kN = 43 kN, must be supported by the cart wheels ( F cw ). Given the symmetry and uniform loading assumptions, the center of gravity of the grain load will be at the geometric center of the bin on the cart. The distance from the hitch point to the grain center of gravity, x g, is:
\( x_{g}= 7 - \frac{5.5}{2}=4.25 \ m\)
The weight of the grain is:
\( F_{g}=\frac{850 \text{ bu}}{1} \cdot \frac{25.4 \text{ kg}}{\text{bu}} \cdot \frac{9.81 \text{ N}}{\text{ kg}} = 212 \text{ kN} \)
The cart and grain must be supported by the cart wheels and by the tractor at the hitch point. These forces are represented as reaction forces R w and R t (Figure 3.3.15). R w is the total weight that the cart wheels and axles must support, which can be calculated by summing the moments about the hitch point between the cart and tractor. If counter-clockwise rotation is positive, that moment equation is:
\( R_{w}(4.6) - F_{cw}(4.6) - F_{g}(4.25) + F_{ct}(0)-R_{t}(0) = 0 \)
Note that because the tongue load and reaction force both pass through the hitch point; their moment arm distances are zero and they fall out of the equation. The moment equation is now solved for R w :
\( R_{w} = \frac{F_{cw}(4.6 \text{ m}) + F_{g}(4.25 \text{ m})}{4.6 \text{ m}} = \frac{43 \text{ kN}(4.6 \text{ m}) + 212 \text{ kNn}(4.25 \text{ m})}{4.6 \text{ m}} = 240 \text{ k} \)
Since there are two wheels, each wheel must support 120 kN.
With the load known, it is possible to calculate the diameter of the cylindrical axle required to support the wheel. The axle (Figure 3.3.16) is a cantilever configuration since it is rigidly fixed to the frame on one end. The simplified configuration of the axle (Figure 3.3.16) shows that the reaction force from the wheel is applied 30 cm out from the base of the axle. The downward force of the cart and grain at the base of the axle and the upward reaction force from the tire will cause bending stress in the axle. The bending moment is:
\( M=Fd=120,000 \text{ N }\cdot 0.3 \text{ m}= 3600 \text{ Nm} \)
The maximum stress in the axle cannot exceed the yield stress of the material, which would cause permanent deformation in the axle, compromising its functionality and strength. The designer needs to know what material will be used to manufacture the axle and then determine the yield stress for that particular material. A number of material engineering handbooks and other resources can be consulted to find the yield stress of different materials. For this example, assume that mild steel would be used. The yield stress for mild steel ( σ y ) can be found from a number of resources to be 250 MPa. Note that a Pa is defined as a N/m 2 . The bending stress in the axle is (Equation 3.3.8):
\( \sigma_{b} = \frac{My}{I} \)
Note that y is the distance from the neutral axis, which is the center of the circular shaft. The maximum stress will occur at the top and bottom of the axle. The equations for moment of inertia for different cross-sectional shapes can be found in a number of engineering handbooks or strength of materials text books. For a circular cross section, the moment of inertia is:
\[ I = \frac{1}{4} \pi r^{4} \]
Substituting Equation 3.3.21 into Equation 3.3.8, the bending stress equation becomes:
\( \sigma_{b} = \frac{4My}{\pi r^{4}} \)
Since the critical failure point will be at the outermost fibers of the circular cross section, the stress will be calculated at y = r . Also, the stress at those outermost fibers should not exceed the yield stress; therefore,
\( \sigma_{y} = \frac{4M}{\pi r^{3}} \)
Now solve for r :
\( r^{3}=\frac{4M}{\pi \sigma_{y}} \ \cdot \frac{3600 \text{ Nm}}{1} \ \cdot \frac{m^{2}}{350 \times 10^{6} \text{ N}} \)
The calculated minimum radius is 2.6 cm.
Any calculated number or computer output should always be scrutinized to make sure that it represents a reasonable conclusion. In this case, an experienced engineer should be concerned that a 2.6-cm radius axle seems unusually small for a large grain cart. There are several factors that were not considered in the analysis. First, the load on the axle was the static weight of the cart and grain. There was no consideration for peak dynamic loads that would be induced as the vehicle moved across the terrain of a farm field. The dynamic analysis would also need to consider fatigue stress in the material due to repeated loading. There was no safety factor considered to compensate for inconsistencies in material properties of the axle or overloading of the cart by the operator. Depending on the method of attachment of the axle to the frame, there could be significant stress concentrations at sharp corners or weldments. These stress concentrations are usually identified with a finite element analysis of the structure. But even if catastrophic failure did not occur in the mechanism, the engineer should consider the effects of the elasticity of the axle. In this case, excessive elastic deflection in the axle could cause the tire to become misaligned, which could cause adverse tracking of the cart or unacceptable wear of the tire. All these factors would need to be addressed to achieve a final design that prevents failure and assures proper operation.
Image Credits
Figure 1. Stombaugh, T. (CC By 4.0). (2020). Typical grain combine.
Figure 2. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Forces acting on grain.
Figure 3. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Simple sieve mechanism.
Figure 4. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Drag forces.
Figure 5. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Paddle conveyor.
Figure 6. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020).
Figure 7. Stombaugh, T. (CC By 4.0). (2020). Combine and baler.
Figure 8. Stombaugh, T. (CC By 4.0). (2020). Row crop head.
Figure 9. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Conventional threshing cylinder.
Figure 10. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Rotary threshing cylinder.
Figure 11. Stombaugh, T. (CC By 4.0). (2020). Combine and grain cart.
Figure 12. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Combine test locations.
Figure 13. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Gathering reel.
Figure 14. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Tractor and grain cart.
Figure 15. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Forces on grain cart.
Figure 16. Stamper, D. & Stombaugh, T. (CC By 4.0). (2020). Axle configuration.
References
ASABE Standards. (2015a). ASAE EP496.3 FEB2996 (R2015): Agricultural machinery management. St. Joseph, MI: ASABE.
ASABE Standards. (2015b). ASAE D497.7 MAR2011 (R2015): Agricultural machinery management data. St. Joseph, MI: ASABE.
Srivastava, A. K., Goering, C. E., Rohrbach, R. P., & Buckmaster, D. R. (2006). Engineering principles of agricultural machines (2nd ed.). St. Joseph, MI: ASABE.


11.3: Documentation of Medication Administration
By the end of this section, you will be able to:
- Describe the nursing guidelines for documenting medication administration
- Explain the importance of accuracy in documentation of medication administration
- Demonstrate how to correctly document in a medication administration record (MAR)
Documentation of medication administration is part of the patient’s legal medical record. Not only does the documentation play a critical role in clinical decision-making, but it may also be used in situations when legal action might be initiated. For these reasons, it is critical that this documentation be accurate, complete, reliable, and timely. This section prepares you with the knowledge and skills to accurately document medication administration in the patient’s medical record.
Nursing Guidelines for Documentation of Medication Administration
After completion of administering medications, the nurse is responsible for documenting the medication administration as well as any required postadministration assessments. This step is the one in which the medication administration “rights” of right documentation and right response are verified. To ensure accurate documentation, guidelines have been developed to ensure that only approved abbreviations are used, documentation is timely, and there is adequate evaluation of the patient’s response to the medication.
Approved Abbreviations
When documenting medication administrations, it is important to use only approved abbreviations to avoid potential medication errors. Agencies should incorporate standardized abbreviations to ensure consistency and reduce confusion. Using data from the ISMP’s National Medication Errors Reporting Program, there are a number of error-prone abbreviations that have been linked to medication errors, which should be considered when creating standardized abbreviations. Although these abbreviations are suggestions for agencies to strongly consider avoiding, The Joint Commission’s published list of “Do Not Use” abbreviations that must be avoided should be incorporated into the organization’s “Do Not Use” list.
To avoid confusion, medication names should typically be spelled out in full. For example, abbreviations for hydrocortisone (HCT) and hydrochlorothiazide (HCTZ) may be mistaken. Likewise, oxytocin (OXY) may be mistaken for oxycodone or oxycontin. Although the decision of whether using abbreviations is allowed is at the discretion of individual agencies, certain abbreviations should never be used based on evidence-based standards and implemented regulations by accrediting agencies. For instance, the abbreviations for magnesium sulfate (MgSO 4 ) and morphine sulfate (MSO 4 ) must never be used due to the high risk of significant negative patient outcomes should an error occur. Medications that are enteric-coated may include EC to the right of the drug name, whereas extended-release medications may use ER or XR, and sustained release may use SR. You may also see antibiotics generally referred to as abx; however, documentation of the medication administration should list the antibiotic name in full.
When expressing dosages, it is best practice to avoid fractions and roman numerals. Fractions may be misinterpreted as a range, and roman numerals may be mistaken as a letter or the wrong number. For example, “1/2 tablet” may be mistaken as “1–2 tablets,” and “V” may be mistaken as the letter V or 10. Instead, using “half tablet” and “5” reduces the risk of confusion and error. Remember that trailing zeros should be avoided, and leading zeros should be used before a decimal point. For example, use 5 mg instead of 5.0 mg, as 5.0 mg may be mistaken for 50 mg. Likewise, use 0.25 mg instead of .25 mg, as .25 mg may be mistaken for 25 mg. Adequate space must be placed between the drug name, dose, and unit of measurement to avoid misinterpretation. For example, metoprolol 25 mg may be mistaken as metoprolol 125 mg without the necessary space between the medication name and dose, or it may be mistaken as 2500 g without the necessary space between the dosage amount and unit of measurement. Another best practice is to use commas when numbers are greater than one thousand. For example, use 100,000 units instead of 100000 units, which may incorrectly be transcribed as 1000000. Careful consideration should also be given to the measurement units. For example, use mL for milliliter instead of ml or cc; L for liter instead of l; units instead of IU, U, or u; and mcg for micrograms instead of µg. Drops may be expressed as gtt.
When expressing medication routes, writing out the route in full is the best way to avoid mistakes. However, some agencies may allow abbreviations for the route, such as right ear (AD), left ear (AS), each ear (AU), right eye (OD), left eye (OS), and each eye (OU). If agency policy allows other abbreviations for routes, these may include NAS (intranasal), PO (oral), SUBQ (subcutaneous), IM (intramuscular), IV (intravenous), IVP (intravenous push), and IVBP (intravenous piggyback). In addition, some medications, such as injections, require the administration site to be documented.
When expressing frequency, writing the frequency in full (i.e., daily, at bedtime, daily at 8 AM, 4 times daily) is safest. “Q” is often used to denote “every.” For example, daily may be written as QD or Q1d, but writing out “daily” is recommended. Similarly, orders may be written in terms of every so many minutes, hours, days (i.e., Q30 min, Q6h, Q2d). Nightly at bedtime may be abbreviated as HS or QHS; however, the ISMP recommends using just HS, nightly, or to spell out “at bedtime.” Medication frequency may also be expressed in relation to meals; for example, before meal (ac), after meals (pc), and before meals and at bedtime (achs).
Typically, symbols are not recommended when documenting medications. Instead of using > and <, best practice is to spell out the words more than and less than . Similarly, it is better to write out increase and decrease rather than to use directional arrows. Other symbols, such as @ and & may be mistaken as a 2 when handwritten, and + may be mistaken as a 4. Therefore, it is better to use the words at , and , plus , or in addition to . Weights should be stated as lb or kg instead of # to avoid confusion of whether the symbol is referring to a number or to pounds.
View The Joint Commission’s Do Not Use List Fact Sheet here. View the Institute for Safe Medication Practices’ List of Error-Prone Abbreviations here.
Timing of Documentation
Medications should be documented immediately after they are administered. Documenting at the time of administration reduces the potential for error and helps to ensure the most accurate documentation. It also reduces the likelihood of duplicate administration and may alert the clinician to changes in the patient’s condition.
Medication administration should not be documented prior to the administration, as the patient’s current condition may impact the ability to administer the medication. For example, the nurse may document the IV medication before administration, only to find the IV had infiltrated upon entering the patient’s room. Other examples may include documenting oral medications before administration, only to find the patient cannot safely swallow, or documenting that a medication was given, only for the patient to refuse the medication when it is administered. Not only may the patient’s condition change, but there is also a risk of the nurse documenting the administration of the medication and then forgetting to administer the medication.
Evaluation of Medication
After administering medications, it is important for the nurse to ensure the medication had the intended outcome, as part of the nursing process. For instance, did the patient’s blood pressure decrease after administering blood pressure medication? Did the patient’s fever decrease after administering a fever reducer? If the medication did not result in the intended outcome, it is important for the nurse to report the patient’s response, or lack thereof, to the provider, as well as document the response in the patient’s chart.
The timing of this evaluation depends on the onset of the medication. Typically, oral medications should be evaluated within 30 minutes to one hour after administration, whereas IV medications should be assessed much sooner. Depending on the medication administered via the IV route, evaluation can occur from five minutes to 15 minutes after administration. Although these are guidelines, the nurse should follow the agency’s policies regarding time frame for evaluation of medications.
In addition to the intended response, the nurse should document any noted adverse reaction following the administration, including any allergic responses. For example, the nurse may note a rash on the patient’s body 30 minutes after administering a new medication. The nurse should document the patient’s reaction to the medication within the medication administration record (MAR) and write a progress note detailing the patient’s response to the medication. The progress note should also include a statement that the provider was notified and any additional orders that may have been received.
Medications administered on a PRN basis must also be evaluated. When administering the medication, the indication for the PRN medication must be clearly identified. For example, if Benadryl is administered PRN itching, the nurse must document the assessment findings related to the itching. If the medication is being administered for pain, then a pain assessment must be performed and documented. The nurse must also reassess the PRN indication according to the medication’s onset, documenting the patient’s response. For example, if an oral pain medication is administered, the nurse may reassess the pain about 30 minutes to one hour after administering pain medications, whereas the patient’s pain should be assessed within 10–15 minutes after administering an IV pain medication.
Accuracy of Documentation
Thorough and accurate documentation is critical for clinical decision-making and the delivery of high-quality care. The patient’s medical record serves as a communication tool for the interdisciplinary team and is crucial for ensuring continuity of care. Not only does accurate documentation inform the care team of the patient’s current situation and allow for treatment decisions to be made, but it also provides legal evidence that may be used in the court of law. Therefore, accurate documentation is needed to provide the very best care and to mitigate risks.
Patient Refusal of Medication
Patients have rights, including the right to refuse medications. Should the patient refuse a medication, the first step is to determine why the patient is refusing the medication. Once the reason for refusing the medication has been determined, the nurse can then plan how best to proceed. For example, the nurse may determine the patient is refusing the medication because at home they typically take the medication at night instead of in the morning. The nurse may then collaborate with the pharmacy to reschedule the dose for nighttime. Or perhaps the patient experiences difficulty swallowing. The patient may refuse to take the medications whole but is amenable to taking the medications crushed in applesauce.
Within this assessment, the nurse should also understand why the medication is necessary. There may be times when patients lack the capacity to make sound decisions. It is important to consider if the patient has the capacity to fully understand the implications and make an informed decision to refuse the medication. For example, some mental health conditions such as dementia, conditions that cause a lack of consciousness, and intoxication may prohibit the patient from being fully aware of the implications of their decisions. Another instance may be children refusing medication out of fear without being able to fully make an informed decision. Although the child may not want to take the medication, the decisional capacity lies within the caregiver to provide consent.
It is important to listen to the patient, identify their concerns, ask questions to better understand the patient’s perspective, and provide clarity to ensure the patient is appropriately informed. The nurse may express a different viewpoint of the situation; however, the nurse should avoid arguing with the patient or minimizing the patient’s concerns. It may also be helpful to provide the patient with options, when possible, to allow the patient more control over the situation. For example, the patient may refuse a suppository but be amenable to taking an oral form of the medication. Another strategy may be to include the patient’s family or caregiver. For example, the patient may refuse medications administered by the nurse but will take the medications if administered by a trusted family member.
There may also be times where an alternative is not possible. In these cases, it is crucial to educate the patient. This education may include why the medication was prescribed, the benefits, as well as potential health outcomes if the medication is not administered. By educating the patient, the patient may make an informed decision to refuse the medication. Another strategy may be to give the patient time to consider the decision and then follow up with the patient a few minutes later to see if they have reconsidered taking the medication.
Nurse : Mr. Blackwell, I see your breakfast arrived, so I went ahead and brought your insulin.
Patient : I’m not taking insulin.
Nurse : Can you tell me a little bit about why you don’t want to take it?
Patient : I don’t take insulin at home. I take metformin at home, which I’ve already had today.
Nurse : I do see the metformin listed here on your home medication list; however, your provider would also like for you to take insulin while you are here in the hospital. Factors such as stress, surgery, and antibiotics are known to increase blood sugar levels. Therefore, the insulin is used in combination with your metformin to better control your blood sugar since you just had surgery and are on antibiotics.
Patient : I know what increases blood sugar levels; however, I’m still not taking insulin.
Nurse : Mr. Blackwell, can you tell me what your blood sugar typically runs at home?
Patient : About 114.
Nurse : This morning, your blood sugar is 152. It likely increased due to having surgery yesterday, the antibiotics, and overall stress on your body. The insulin will help to bring your blood sugar down to your normal range. We use a sliding scale, so we can tailor the insulin dosage according to your blood sugar level.
Patient : Maybe so, but I’m still not taking it.
Nurse : Mr. Blackwell, I understand you don’t take insulin at home, and you seem to understand that your blood sugar may be higher than usual. Can you help me to better understand why you don’t want to take insulin?
Patient : I’m afraid if start taking it now that the doctor will want to keep me on it when I go home.
Nurse : I appreciate your concern; however, the intent is not to send you home with insulin. It is intended to help control your blood sugar just while you are here in the hospital. When you go home, you will go home on your usual metformin.
Patient : I’m still not taking it.
Nurse : I will let your provider know of your concern with taking insulin. Given your blood sugar is higher than normal, you may consider limiting food and drink high in sugar and carbohydrates to provide the best control over your blood sugar. Do you know what carbohydrates are?
Patient : Yes, things like potatoes, crackers, pasta . . . all of my favorite foods.
Nurse : While they may be your favorite foods, avoiding them right now is necessary if you want to try to avoid insulin.
Patient : I understand and will certainly watch what I eat and drink. No soda or spaghetti for me.
If the patient refuses a medication, it is important to notify the provider and chart the refusal. This may include documenting the refusal in the MAR, as well as writing a nursing note in the chart that clearly states the patient’s capacity for decision-making, rationale for the refusal, education provided, and other actions taken by the nurse (including notifying the provider) (Figure 11.6). Any direct quotes provided by the patient should be included within the note; however, be cautious that the patient’s exact words are used if quotation marks are used.
Correcting an Error in Documentation
Errors in documentation should be corrected as soon as they are noticed, and the manner depends on whether the documentation is in electronic or paper format. If the medication is documented electronically, you can typically correct the error by clicking on the medication administration tab within the MAR and then proceed to edit the documentation. Although the electronic chart may be updated daily, most electronic medical records keep a log of all edits made. Although errors should be corrected when they occur, corrections should not be a common occurrence and may indicate too many distractions, or the nurse may need to pay closer attention to the task at hand.
When documentation is handwritten on paper, mistaken entries may be noted by drawing a single line through the error, along with the date and your initials. It is important to use only one line to strike through the error. Do not use multiple lines, squiggly lines, Wite-Out, or attempt to erase the error.
Medication Administration Record
The medication administration record (MAR) is used to document medication administration. The MAR is a comprehensive record that tracks the medications that have been administered, the dose, the route, the time administered, any instructions that were provided, who administered the medication, and who ordered the medication. It should also list the indication for PRN medications, the effectiveness of PRN medication, and any medication reactions noted.
The electronic medication administration record (eMAR) is electronically populated according to the provider’s orders and often automatically populates much of the necessary documentation, such as the drug, route, PRN indication, provider’s name, and name of the person administering the medication (based on the log-on information provided). Typically, the time is defaulted to real time (as medications should be administered in real time); however, the nurse may alter the time, if needed. The eMAR provides additional layers of safety, such as displaying administration instructions, prompts when additional assessments are required, and pop-up alerts to notify the nurse of potential problems, such as contraindications, allergies, the administration being too close to another administration, or that the medication has been discontinued (Figure 11.7). Although the eMAR is convenient and offers a multitude of safety features, it is important for the nurse to use their own clinical judgment when documenting medication administrations and not become reliant on the eMAR.
The nurse must also know how to document medication administrations via a paper MAR (Figure 11.8), as some agencies do not use eMARs, and those that do are subject to “downtime” in which the eMAR may not be available. When using a paper MAR, the medication order information, such as medication name, dose, route, frequency, prescriber name, and order date and time, must be accurately transcribed for each medication order, followed by the time in which the medication should be administered. Each MAR displays a particular time frame, typically for as much as one month, with the dates of the month typically indicated horizontally across the top of the MAR. Each agency may utilize their own MAR template; therefore, the location of each component may slightly vary.
To document a medication administration, the nurse would place their initials in the box associated with the date and time of administration. Subsequently, the MAR indicates a place for the nurse to record their initials, print their name, and add their signature, so that initials may be correctly identified should the need arise. If a medication is to be administered more than one time per day, it is best practice to leave a couple of lines between the scheduled time rows to prevent the initials from running together. If the medication dose is ordered as a range, the dose may be indicated in the box closest in proximity to the nurse’s initials. A line should be placed through any dates in which the medication should not be administered, for example, any dates that occurred prior to the medication order or after the medication was discontinued. Once the medication is discontinued, the nurse should ensure a line is placed through all subsequent dates, highlight the row yellow, and indicate if the medication order was changed or discontinued, along with providing the date and their initials.
In the event the dose is missed—perhaps the patient was not available during the scheduled time or the patient refused the medication—the nurse should place a circle around their initials in the box associated with the administration date and time, and then add a note to the back of the MAR to indicate why the medication was not given. Evaluation of the medication, including patient’s response to medication, PRN assessments, any other pertinent information should also be captured on the back of the MAR. Any follow-up assessments should also indicate the time frame in which the reassessment occurred.


13.1: The Hydrological Cycle
Water is constantly on the move. It is evaporated from the oceans, lakes, streams, the surface of the land, and plants (transpiration) by solar energy (Figure \(\PageIndex{1}\)). It is moved through the atmosphere by winds and condenses to form clouds of water droplets or ice crystals. In response to the pull of gravity it comes back down as rain or snow and then flows through streams, into lakes, and eventually back to the oceans. Water on the surface and in streams and lakes infiltrates the ground to become groundwater. Groundwater slowly moves through the rock and surficial materials. Some groundwater returns to other streams and lakes, and some goes directly back to the oceans.
Even while it’s moving around, water is stored in various reservoirs. The largest, by far, is the oceans, accounting for 97% of the volume. Of course, that water is salty. The remaining 3% is fresh water. Two-thirds of our fresh water is stored in ice and one-third is stored in the ground. The remaining fresh water—about 0.03% of the total—is stored in lakes, streams, vegetation, and the atmosphere. To put that in perspective, let’s imagine putting all of Earth’s water into a 1 litre jug (Figure \(\PageIndex{2}\)). We start by almost filling the jug with 970 millilitres of water and 34 grams of salt. Then we add one regular-sized (roughly 20 millilitres) ice cube (representing glacial ice) and two teaspoons (roughly 10 millilitres) of groundwater. All of the water that we see around us in lakes and streams and up in the sky can be represented by adding three more drops from an eyedropper.
Although the proportion of Earth’s water that is in the atmosphere is tiny, the actual volume is huge. At any given time, there is the equivalent of approximately 13,000 cubic kilometers (km 3 ) of water in the air in the form of water vapor and water droplets in clouds. Water is evaporated from the oceans, vegetation, and lakes at a rate of 1,580 km 3 per day, and just about exactly the same volume falls as rain and snow every day—over both the oceans and land. The precipitation that falls on land goes back to the ocean in the form of stream flow (117 km 3 /day) and groundwater flow (6 km 3 /day). Most of the rest of this chapter is about that 117 km 3 /day of streamflow. The average discharge of the Fraser River into the ocean is approximately 0.31 km 3 /day, or 0.26% of the total flow of all rivers.
The residence time of a water molecule in the atmosphere (or any of the other reservoirs) can be estimated by dividing the amount that is there by the rate at which it is transferred in and out. For the atmosphere, we know that the reservoir size is 13,000 km 3 , and the rate of flux is 1,580 km 3 per day. That’s the amount that goes into or comes out of the atmosphere in a day. If we divide 13,000 by 1,580, we get 8.22 days. This means that, on average , a molecule of water stays in the atmosphere for just over eight days. “Average” needs to be emphasized here because obviously some molecules stay in the air for only a few hours, while others may stay up there for weeks.
The volume of the oceans is 1,338,000,000 km 3 and the flux rate is approximately the same (1,580 km 3 per day). What is the average residence time of a water molecule in the ocean?
See Appendix 3 for Exercise 13.1 answers .
Media Attributions
- Figure \(\PageIndex{1}\): “Water Cycle Blank” © Ingwik. Adapted by Steven Earle. CC BY-SA.
- Figure \(\PageIndex{2}\): © Steven Earle. CC BY. Based on data from The Water Cycle: Freshwater Storage .


20: Between the Stars - Gas and Dust in Space
Where do stars come from? We already know from earlier chapters that stars must die because ultimately they exhaust their nuclear fuel. We might hypothesize that new stars come into existence to replace the ones that die. In order to form new stars, however, we need the raw material to make them. It also turns out that stars eject mass throughout their lives (a kind of wind blows from their surface layers) and that material must go somewhere. What does this “raw material” of stars look like? How would you detect it, especially if it is not yet in the form of stars and cannot generate its own energy?
One of the most exciting discoveries of twentieth-century astronomy was that our Galaxy contains vast quantities of this “raw material”—atoms or molecules of gas and tiny solid dust particles found between the stars. Studying this diffuse matter between the stars helps us understand how new stars form and gives us important clues about our own origins billions of years ago.
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- 20.1: The Interstellar Medium
- About 15% of the visible matter in the Galaxy is in the form of gas and dust, serving as the raw material for new stars. About 99% of this interstellar matter is in the form of gas—individual atoms or molecules. The most abundant elements in the interstellar gas are hydrogen and helium. About 1% of the interstellar matter is in the form of solid interstellar dust grains.
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- 20.2: Interstellar Gas
- Interstellar gas may be hot or cold. Gas found near hot stars emits light by fluorescence, that is, light is emitted when an electron is captured by an ion and cascades down to lower-energy levels. Most hydrogen in interstellar space is not ionized and can best be studied by radio measurements of the 21-centimeter line. Some of the gas in interstellar space is at a temperature of a million degrees, even though it is far away in hot stars.
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- 20.3: Cosmic Dust
- Interstellar dust can be detected: (1) when it blocks the light of stars behind it, (2) when it scatters the light from nearby stars, and (3) because it makes distant stars look both redder and fainter. These effects are called reddening and interstellar extinction, respectively. Dust can also be detected in the infrared because it emits heat radiation. Dust is found throughout the plane of the Milky Way.
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- 20.4: Cosmic Rays
- Cosmic rays are particles that travel through interstellar space at a typical speed of 90% of the speed of light. The most abundant elements in cosmic rays are the nuclei of hydrogen and helium, but electrons and positrons are also found. It is likely that many cosmic rays are produced in supernova shocks.
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- 20.5: The Life Cycle of Cosmic Material
- Interstellar matter is constantly flowing through the Galaxy and changing from one phase to another. At the same time, gas is constantly being added to the Galaxy by accretion from extragalactic space, while mass is removed from the interstellar medium by being locked in stars. Some of the mass in stars is, in turn, returned to the interstellar medium when those stars evolve and die.
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- 20.6: Interstellar Matter around the Sun
- The Sun is located at the edge of a low-density cloud called the Local Fluff. The Sun and this cloud are located within the Local Bubble, a region extending to at least 300 light-years from the Sun, within which the density of interstellar material is extremely low. Astronomers think this bubble was blown by some nearby stars that experienced a strong wind and some supernova explosions.
Thumbnail: This image, taken by the Hubble Space Telescope, shows the young star cluster NGC 3603 interacting with the cloud of gas from which it recently formed. The bright blue stars of the cluster have blown a bubble in the gas cloud. The remains of this cloud can be seen in the lower right part of the frame, glowing in response to the starlight illuminating it. In its darker parts, shielded from the harsh light of NGC 3603, new stars continue to form. Although the stars of NGC 3603 formed only recently, the most massive of them are already dying and ejecting their mass, producing the blue ring and streak features visible in the upper left part of the image. Thus, this image shows the full life cycle of stars, from formation out of interstellar gas, through life on the main sequence, to death and the return of stellar matter to interstellar space. (credit: modification of work by NASA, Wolfgang Brandner (JPL/IPAC), Eva K. Grebel (University of Washington), You-Hua Chu (University of Illinois Urbana-Champaign))


3.9: Where?
Where do early childhood programs take place?
In Chapter 6 (Curriculum) and Chapter 7 (Learning Environments), you will be introduced to different types of programs, which sometimes determines where they occur. For now, here is a list of the most common places for young children to develop and grow:
- The child’s home - this is often a child’s first classroom and many important skills are developed here
- Someone else’s home - often-called home daycare or family childcare, there are a variety of types of programs that are run inside caregivers' homes.
- A church, synagogue, or other place of worship - often built for their own programs that take place on the weekends, these are empty during the week and can accommodate multiple uses. Programs operating in such locations may or may not be affiliated with the establishment that owns the building.
- A school setting - either specifically designed for the age group served or modified to meet the needs of various ages.
- A park or community center – some community spaces are dedicated to serving children in a variety of ways.
- Online - synchronously (at the same time) or asynchronously (at different times independently)
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New Teacher Comments “In my practicum class, I was surprised to learn about all of the different places we could train. I thought a school setting was the only place, but there were so many wonderful options. COVID 19 meant that our in-person program needed to be moved to an online format. Some teachers got really creative with Zoom, Google Classroom, video chats, and other technology. One of my colleagues started with show and tell where she had each child in the class take a turn sharing whatever they wanted about their home. We saw bedrooms, favorite toys and met so many pets and family members. It was a wonderful way to connect! Interviewing different places I learned that it is not the building but what goes on inside and outside that makes the magic happen.” |
Where do I go to get more involved?
The resources above in the “When” section are a great place to get started. Ask your instructor if you would like to inquire further.


17.1: Is Planning Important?
- Understand the importance of planning and why organizations need to plan and control.
Planning is the process by which managers establish goals and specify how these goals are to be attained. Plans have two basic components: outcome or goal statements and action statements. Outcome or goal statements represent the end state—the targets and outcomes managers hope to attain. Action statements reflect the means by which organizations move forward to attain their goals. British prime minister Theresa May is determined to change the way that public companies’ boards are comprised of advocating that employees be part of every board. As a part of her action statement, she advocated putting an employee representative in every boardroom, just like Mick Barker, a railway worker since the 1970s, has been quietly helping to shape decision-making as a member of the board of directors at the top of transport giant First Group. 2
Planning is an intellectual activity. 3 It is difficult to see managers plan because most of this activity unfolds in the mind of those doing the planning. While planning, managers have to think about what has to be done, who is going to do it, and how and when they will do it. Planners think both retrospectively (about past events) and prospectively (about future opportunities and impending threats). Planning involves thinking about organizational strengths and weaknesses, as well as making decisions about desired states and ways to achieve them. 4
Planning for organizational events, whether in the internal or external environment, should be an ongoing process—part of a manager’s daily, weekly, and monthly duties and a routine task for all members of high-involvement organizations. Plans should be continually monitored. Managers and other organizational members should check to see if their plans need to be modified to accommodate changing conditions, new information, or new situations that will affect the organization’s future. Plans need to be administered with flexibility, as organizations learn about new and changing conditions. Clearly, the Calico Candy Company failed to monitor its plans in this way. By thinking of planning as a continuous activity, methods can be formulated for handling emerging and unforeseen opportunities and threats. Planning is one process through which organizational activity can be given meaning and direction.
Why Should Managers Plan?
Managers have several reasons for formulating plans for themselves, their employees, and various organizational units: (1) to offset uncertainty and change; (2) to focus organizational activity on a set of objectives; (3) to provide a coordinated, systematic road map for future activities; (4) to increase economic efficiency; and (5) to facilitate control by establishing a standard for later activity.
Several forces contribute to the necessity for organizational planning. First, in the internal environment, as organizations become larger and more complex, the task of managing becomes increasingly complex. Planning maps out future activities in relation to other activities in the organization. Second, as the external environment becomes increasingly complex and turbulent, the amount of uncertainty faced by a manager increases. Planning enables organizations to approach their environment systematically.
A study out of Cornell University and Indiana University found that absenteeism costs companies $40 billion per year; the absence of planning was one of the biggest problems businesses face. Firms that follow a clearly defined plan in their day-to-day operations will be more successful than those that do not. The authors state, “organizational controlled consequences that would tend to deter absenteeism.” Interestingly, this may be as simple as inspecting the organizational policies that provide the “rules” for employee absenteeism. 5
Do Managers Really Plan?
Managers should plan formally, but do they? Some observers contend that managers typically are too busy to engage in a regular form of systematic planning. McGill University management professor Henry Mintzberg notes:
When managers plan, they do so implicitly in the context of daily actions, not in some abstract process reserved for two weeks in the organization’s mountain retreat. The plans of the chief executives I have studied seemed to exist only in their heads—as flexible, but often specific, intentions. . . . The job of managing does not breed reflective planners; the manager is a real-time responder to stimuli. 6
Others disagree. After reviewing a number of studies focused on the degree to which planning and other managerial activities are inherent parts of managing, management professors J. Carroll and J. Gillen state that “the classical management functions of Fayol, Urwick, and others are not folklore as claimed by some contemporary management writers but represent valid abstractions of what managers actually do and what managers should do.” 7 Barbara Allen, president of Sunbelt Research Associates, notes that she did a considerable amount of planning before launching her new business. Now that she is operating successfully, she reviews and updates her plans periodically. 8
Managers often are very busy people. Some act without a systematic plan of action; however, many managers do plan systematically. 9 For example, many managers develop systematic plans for how their organization will react to a crisis. United Airlines, for example, created a crisis planning group. The group developed United’s crisis contingency plan book, which specifies what the airline’s crisis management team should do in the event of a crisis. Keri Calagna, principal, Deloitte Risk and Financial Advisory, Deloitte & Touche LLP, comments that up to 20.7% of a firm’s value resides in reputation but that CEOs and 77% of the board of directors members identified reputation risk as the area about which they felt most vulnerable and that only 39% had a plan to address it. 10
The question about whether managers really plan and the observation that many times they are simply too busy to retreat to the mountaintop and reflect on where the organization should be going and how it should get there misses the point: there are different types of planning.
- What is the process where managers establish goals and outline how these goals will be met called?.
- How do the internal and external environments of the organization and its strengths and weaknesses impact the planning process?
- Why should managers plan?


4.4: Spotlight Application
Jamie has recently completed his orientation to the emergency department at a busy Level 1 trauma center. The environment is fast-paced and there are typically a multitude of patients who require care. Jamie appreciates his colleagues and the collaboration that is reflected among members of the health care team, especially in times of stress. Jamie is providing care for an 8-year-old patient who has broken her arm when there is a call that there are three Level 1 trauma patients approximately 5 minutes from the ER. The trauma surgeon reports to the ER, and multiple members of the trauma team report to the ER intake bays. If you were Jamie, what leadership style would you hope the trauma surgeon uses with the team?
In a stressful clinical care situation, where rapid action and direction are needed, an autocratic leadership style is most effective. There is no time for debating different approaches to care in a situation where immediate intervention may be required. Concise commands, direction, and responsive action from the team are needed to ensure that patient care interventions are delivered quickly to enhance chance of survival and recovery.


8.0: What Does Psychology Say?
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Andre and his older brother Omar recently moved to Boston from Brazil, and it has been an exciting yet overwhelming experience for them. Although Andre still considers himself Brazilian, he now is expected to swear allegiance to the U.S. flag at the start of the school day. Omar is discovering that how people greet each other is quite different in the United States. In Brazil, children address teachers as “Tio” or “Tia” and use their first name. In the United States, children are expected to be more distant and respectful toward adults outside of the family.
Andre has pushed himself into his schoolwork and is trying to catch up. While he speaks English and Portuguese, he is struggling to read assignments in English, and this has made him quieter than usual at school. He used to have many friends, but now he has a harder time connecting with peers. Omar is less worried about school and spends most of his time talking and joking, even if the teacher asks him to stop. He just finds school so exciting, with all the social activities and new experiences, and after school he is always playing with new friends at the park.
Andre and Omar’s parents have recently met with the school principal to discuss how the boys are adjusting. They’ve been advised to be patient because Andre and Omar are adapting to a new culture in addition to a new school. The staff are encouraged that Omar seems to have found a group of other kids to play soccer with on the playground. The school counselor believes that Andre will begin making friends once he feels more confident with the social and cultural etiquette and learns more of the regional English slang popular among the middle school age group. For now, she recommends that both Andre and Omar join a local peer mentoring group to help with social and emotional skills while continuing to take their regular classes. The principal explained that because the schoolteachers and staff have training in cultural inclusivity and socioemotional development, the boys will have support to improve their social skills and adjust quickly. Although their parents believe this to be true and have already seen progress, they wonder:
In this chapter, you will learn about the significant social and emotional milestones and dilemmas faced as children in middle childhood, ages seven to twelve years, progress through development.