**Conflict of interest**

The author declares no conflict of interest.

### **Notes/thanks/other declarations**

I would especially like to thank my children who have tolerated "good enough mothering" while growing up on an inclusive green care farm animal sanctuary. They have been great traveling companions during international conferences in Toronto, Canada; Vienna, Austria; and Shanghai, China. My advocacy in raising awareness about ND-PAE in the psychiatric community are supported by my outpatient clinical practice, Therapeutic & Learning Centers, P-LLC (www.susandrich.com) and my nonprofit 501c3, 7th Generation Foundation, Inc. (www.7thGenerationFoundationInc.org).


*Edited by Dongfang Yang*

Laser ablation refers to the phenomenon in which an intense laser beam irradiates the surface of a solid to induce instant local removal of atoms by a thermal or non-thermal mechanism. Through eight chapters of original research studies and literature reviews written by experts from the international scientific community, this book presents theoretical and experimental aspects of the laser ablation phenomenon for processing material including pulsed laser deposition of thin films, laser surface modification, laser machining and laser nanoparticle formation. It also includes a study of the dynamics of plasmas generated by laser ablation of multi-component materials and an overview of laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) techniques for chemical analysis.

ISBN 978-1-83968-303-9

Practical Applications of Laser Ablation

Published in London, UK © 2021 IntechOpen © malija / iStock


**1. Introduction**

Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved cellular catabolic mechanism that facilitates the degradation of damaged cellular organelles and proteins, by targeting them to the lysosomes and recycling the macromolecules for the rebuilding of cellular machinery [**???** ]. Autophagy undergoes rhythmic variation in accordance with circadian patterns of rest/activity and feeding in adult mammals [**?** ]. Dysregulated autophagy has been implicated in several neurodegenerative disorders, hepatitis, cancer, aging associated diseases and in the general aging process [**?????** ]. Recently, a growing body of evidence indicates that dysregulated autophagy is also linked to diabetes [**????** ].

The disruption of circadian rhythm has a profound negative impact on health and is associated with elevated risk for several diseases [**?** ]. The physiological relevance of an altered circadian rhythm in diabetes is evidenced by the observation of a high incidence of myocardial dysfunction, acute coronary syndrome, sudden cardiac death, and ischemic stroke in diabetics during the night, compared to a higher frequency during the day in non-diabetics [**????** ]. In diabetic conditions, Bmal1 and Clock are inactivated, causing deregulated glucose homeostasis and suppressed diurnal variation in glucose and triglycerides, along with reduced gluconeogenesis [**?** ]. Streptozotocin (STZ)-induced type 1 diabetes (T1D) in mice exhibits altered phase of the circadian clock in the heart [**?** ] and a significant reduction of circadian sensitivity to low-intensity light in the retina [**?** ]. Furthermore, STZ-mice develop a deficiency in their ability to re-entrain the circadian rhythm when subjected to a phase advance of the 12L/12D cycle [**?** ]. Bio-Breeding Zucker diabetic rat (BBZDR/Wor) and Goto-Kakizaki rat type 2 diabetes (T2D) models also show impairment of the molecular clock, suggesting that the disruption of the circadian clock is a common phenomenon in both T1D and T2D [**? ?** ].

Several hallmarks of diabetic retinopathy can be recapitulated in rodent retina deficient of clock genes [**? ?** ]. Reduced tube formation and increased senescence of endothelial cells coupled with impaired progenitor-mediated repair is observed in Per2 mutant mice, emphasizing the importance of the circadian clock in retinal homeostasis [**?** ]. Recent studies on autophagy in the retina have shed light on the association of key molecules of the autophagic pathway with phagocytosis of photoreceptor outer segments (POS) by the retinal pigmented epithelium (RPE) [**? ?** ]. Photoreceptor disk shedding has been widely reported to exhibit diurnal rhythmicity in the retina [**? ?** ] and the tight coupling of phagocytic ingestion and autophagic degradation of the POS to this diurnal rhythm is a critical aspect of retinal homeostasis [**? ?** ].

The role of the peripheral clock and diurnal variation on the regulation of autophagy in the normal and diabetic rodent retinas and the fate of autophagy in the diabetic retina remain unexplored. Understanding these control mechanisms may help find e ffective treatments for diabetic retinopathy. In this study, we demonstrate that the spatial distribution and temporal expression of autophagy proteins show a diurnal rhythm and that this is depressed and phase shifted in the diabetic retina.


**Prediction of Herbicides Concentration in Streams**

Raj Mohan Singh *Department of Civil Engineering, MNNIT Allahabad, India*

#### **1. Introduction**

226 Herbicides – Properties, Synthesis and Control of Weeds

Walters, S.M. (1990). Clean-up techniques for pesticides in fatty foods. *Analytica Chimica*

Natural and anthropogenic variables of stream drainage basins such as hydrogeologic parameters (permeability, porosity etc.), amount of agricultural chemicals applied, or percentage of land planted affect agricultural chemical concentration and mass transport in streams. The use of herbicides, pesticides, and other chemicals in agricultural fields increase the concentration of chemicals in streams which severely affects the health of human and environment. The transport of chemical pollutants into river or streams is not straight forward but complex function of applied chemicals and land use patterns in a given river or stream basin. The factors responsible for transport of chemicals may be considered as inputs and chemical concentration measurements in streams as outputs. Each of these inputs and outputs may contain measurement errors. Present work exploited characteristics of fuzzy sets to address uncertainties in inputs by incorporating overlapping membership functions for each of inputs even for limited data availability situations. Soft computing methods such as the fuzzy rule based and ANN (Artificial Neural Networks) is used for characterization of herbicides concentration in streams. The fuzzy c-means (FCM) algorithm is used for the optimization of membership functions of fuzzy rule based models for the estimation of diffuse pollution concentration in streams. The general methodology based on fuzzy, ANN and FCM for estimation of diffuse pollution in streams is presented. The application of the proposed methodology is illustrated with real data to estimate the diffuse pollution concentration in a stream system due to application of a typical herbicide, atrazine, in corn fields with limited data availability. Solution results establish that developed fuzzy rule base model with FCM outperform fuzzy or ANN and capable for the estimation of diffuse pollution concentration values in water matrices with sparse data situations.

Application of pesticides, insecticides and herbicides, cause diffuse pollution, commonly referred to as non-point source pollution in river or streams. Diffuse pollution from agricultural activities is a major cause of concern for the health of human and environment. Diffuse (non-dot, dispersed) pollution generally arises from land-use activities (urban and rural) that are dispersed across a catchment or subcatchment, where as point sources of pollution arise as a process industrial effluent, municipal sewage effluent, deep mine or farm effluent discharge (Novotny 2003, based on CIWEM (D'Arcy et al., 2000)). Potential point sources of pollution is characterised by its location, magnitude and duration of activity; and the sources of pollution is characterized when these parameters are identified

Prediction of Herbicides Concentration in Streams 229

physical, chemical, and biological processes as well as in the data acquisition and parameters for model algorithms. Consequently, the complexities of these models and their resource-intensive nature are significant obstacles to their application (Charbeneau and

There is a need for the development of simpler methods of agricultural stream quality predictions that provide the required information to the analyst and water managers with minimal effort and limited data requirements as compared to complex process models. As an alternative or supplement to complex runoff quality simulation models, fuzzy rule based model with FCM is proposed to estimate pollutant concentration due to applications of

The herbicide atrazine (2-chloro-4-[ethylamino]-6-[isopropylamino]-1,3,5-triazine), a chlorinated herbicide, has been one of the most heavily used herbicides in the world. Atrazine is toxic to many living organism. The maximum contaminant level (MCL) of atrazine is restricted to 3 µg/l for drinking water (USEPA, 2001). Because atrazine is water soluble, it has the potential to leach into ground water and run off to surface water. Atrazine is associated with developmental effects (USEPA, 2002), such as birth defects, structural anomalies, and adverse hormone changes. Thus, its accurate estimation in water matrices is

In this study, a fuzzy rule based model optimized by fuzzy c-Means, is developed to obtain the estimate of atrazine concentrations from agricultural run-off using limited available information. The work discusses the methodology to develop the fuzzy rule base model using annual average use of herbicide atrazine per unit area, extent of herbicide atrazine applied area and herbicide atrazine application season as inputs to fuzzy rule based model and observed herbicide concentration at the basin outlet as the output for the fuzzy model. The data of White River Basin, a part of the Mississippi River system, USA, is used for

Natural and anthropogenic variables of stream drainage basins such as hydrogeologic parameters (permeability, porosity etc.), amount of agricultural chemicals applied, or percentage of land planted affect agricultural chemical concentration and mass transport in streams. The general form of model that simulates the concentration measurement in a

where C is the stream agricultural diffuse pollution observed concentration measurement values; **W** is a vector of watershed characteristics; and **H** is a vector of hydrological variables such as precipitation, runoff, etc., and **A** is a vector of relevant agricultural practices

For a particular watershed, watershed characteristic, **W**, may be assumed to be constant. Also, for a particular hydrological unit, **H** may be assumed to be of similar characteristics.

C = f (**W, H, A**) (1)

C = f (**A**) (2)

**2. Agricultural diffuse pollution concentration simulation in streams**

watershed can be represented by (Tesfamichael et al., 2005)

including actual chemical application rate in the field in lb/acre.

Then, Equation (1), though simplified, may be represented by

agricultural chemical, herbicide, atrazine, in the streams.

Barrett 1998).

imperative.

developing the fuzzy rule base model.

(Mahar and Dattta 2000; Singh and Datta, 2004, and Singh and Datta, 2006a and 2006b). In diffuse sources of pollution or non-point sources of pollution, sources of pollution is moving with polluting media thus making it more difficult and complex problem to solve.

Often diffuse pollution is individually minor but collectively constitutes significant sources at basin scale. Although nonpoint or diffuse sources may contribute many of the same kinds of pollutants, these pollutants are generated in different volumes, combinations, and concentrations (Jha et al., 2005). Thus, diffuse pollution comprises true non-point source pollution together with inputs from a multiplicity of minor point sources. The important characteristics of diffuse pollution are, therefore, not whether anyone can identify the source or sources, but the collective impact of diffuse pollutants and the mechanisms through which they move through the environment. The concept of diffuse pollution is useful because it explains features of pollution in receiving water bodies that differ from the point sources of pollution that are typically well characterized, monitored, and quantified. Some of the characteristics of diffuse pollutants are that the concentrations of some pollutants actually may increase with flow rather than it has diluted, pollution peaks are variable and difficult to predict, and impacts are often slow to develop and become evident years later (e.g. contamination of groundwater). For diffuse pollution, it is the proportion of the land use from which the pollution is derived, is more important.

Agricultural activities such as application of herbicides result in the contamination of surface water with agricultural chemicals. Numerous recent investigations (Goolsby and Battaglin, 1993 and 1995; Schottler et al., 1994; Baker and Richards, 1990) indicate that significant quantities of some herbicides are flushed from cropland to streams each spring and summer during rainfall events following the applications. Peak concentration of several herbicides can exceed 10 µg/l during these events (Coupe et al., 1995; Scribner et al., 1994). Pareira (1990), Crawfard (1995, 2001), Capel and Larson (2001), and Smith and Wheater (2004) in their studies on pesticides/herbicides, identified the major factors that control the pollutant transport. Herbicides and pesticides concentrations in surface waters are affected by natural and human factors. For example, concentrations of atrazine, a herbicide widely used on corn fields, tended to be higher in an agricultural basin with permeable, well drained soils, than in an agricultural basin with less permeable, more poorly drained soils (Crawfard, 1995). Capel et al. (2001) estimated the annual pollutant transport as percent of use (load as percent of use - LAPU). Larson and Gilliom (2001) developed a regression model for the estimation of pollutants.

Water resources professionals, managers and government authorities involved in surface water management are increasingly pressed to make appropriate decisions on land use and development policies such that these decisions will not adversely affect the health and environment. At the same time, they are constrained by inadequate budgets, limited resources, and incomplete information, which compel them to rely on models to evaluate or to estimate the pollution characteristics in the water bodies, and the implications of their decisions based on those evaluations. In this regard, the role of complex stream quality simulation models e.g. SWAT (Arnold et al. 1983), AGNPS (Young et al., 1989) etc. in evaluating runoff pollution conditions under various agricultural chemicals and land use patterns is also limited. These models incorporate rainfall, catchments, and pollutant characteristics, requiring extensive calibration and verification. However, their results are not without large uncertainties. These uncertainties arise both in the representation of the

(Mahar and Dattta 2000; Singh and Datta, 2004, and Singh and Datta, 2006a and 2006b). In diffuse sources of pollution or non-point sources of pollution, sources of pollution is moving

Often diffuse pollution is individually minor but collectively constitutes significant sources at basin scale. Although nonpoint or diffuse sources may contribute many of the same kinds of pollutants, these pollutants are generated in different volumes, combinations, and concentrations (Jha et al., 2005). Thus, diffuse pollution comprises true non-point source pollution together with inputs from a multiplicity of minor point sources. The important characteristics of diffuse pollution are, therefore, not whether anyone can identify the source or sources, but the collective impact of diffuse pollutants and the mechanisms through which they move through the environment. The concept of diffuse pollution is useful because it explains features of pollution in receiving water bodies that differ from the point sources of pollution that are typically well characterized, monitored, and quantified. Some of the characteristics of diffuse pollutants are that the concentrations of some pollutants actually may increase with flow rather than it has diluted, pollution peaks are variable and difficult to predict, and impacts are often slow to develop and become evident years later (e.g. contamination of groundwater). For diffuse pollution, it is the proportion of the land

Agricultural activities such as application of herbicides result in the contamination of surface water with agricultural chemicals. Numerous recent investigations (Goolsby and Battaglin, 1993 and 1995; Schottler et al., 1994; Baker and Richards, 1990) indicate that significant quantities of some herbicides are flushed from cropland to streams each spring and summer during rainfall events following the applications. Peak concentration of several herbicides can exceed 10 µg/l during these events (Coupe et al., 1995; Scribner et al., 1994). Pareira (1990), Crawfard (1995, 2001), Capel and Larson (2001), and Smith and Wheater (2004) in their studies on pesticides/herbicides, identified the major factors that control the pollutant transport. Herbicides and pesticides concentrations in surface waters are affected by natural and human factors. For example, concentrations of atrazine, a herbicide widely used on corn fields, tended to be higher in an agricultural basin with permeable, well drained soils, than in an agricultural basin with less permeable, more poorly drained soils (Crawfard, 1995). Capel et al. (2001) estimated the annual pollutant transport as percent of use (load as percent of use - LAPU). Larson and Gilliom (2001) developed a regression

Water resources professionals, managers and government authorities involved in surface water management are increasingly pressed to make appropriate decisions on land use and development policies such that these decisions will not adversely affect the health and environment. At the same time, they are constrained by inadequate budgets, limited resources, and incomplete information, which compel them to rely on models to evaluate or to estimate the pollution characteristics in the water bodies, and the implications of their decisions based on those evaluations. In this regard, the role of complex stream quality simulation models e.g. SWAT (Arnold et al. 1983), AGNPS (Young et al., 1989) etc. in evaluating runoff pollution conditions under various agricultural chemicals and land use patterns is also limited. These models incorporate rainfall, catchments, and pollutant characteristics, requiring extensive calibration and verification. However, their results are not without large uncertainties. These uncertainties arise both in the representation of the

with polluting media thus making it more difficult and complex problem to solve.

use from which the pollution is derived, is more important.

model for the estimation of pollutants.

physical, chemical, and biological processes as well as in the data acquisition and parameters for model algorithms. Consequently, the complexities of these models and their resource-intensive nature are significant obstacles to their application (Charbeneau and Barrett 1998).

There is a need for the development of simpler methods of agricultural stream quality predictions that provide the required information to the analyst and water managers with minimal effort and limited data requirements as compared to complex process models. As an alternative or supplement to complex runoff quality simulation models, fuzzy rule based model with FCM is proposed to estimate pollutant concentration due to applications of agricultural chemical, herbicide, atrazine, in the streams.

The herbicide atrazine (2-chloro-4-[ethylamino]-6-[isopropylamino]-1,3,5-triazine), a chlorinated herbicide, has been one of the most heavily used herbicides in the world. Atrazine is toxic to many living organism. The maximum contaminant level (MCL) of atrazine is restricted to 3 µg/l for drinking water (USEPA, 2001). Because atrazine is water soluble, it has the potential to leach into ground water and run off to surface water. Atrazine is associated with developmental effects (USEPA, 2002), such as birth defects, structural anomalies, and adverse hormone changes. Thus, its accurate estimation in water matrices is imperative.

In this study, a fuzzy rule based model optimized by fuzzy c-Means, is developed to obtain the estimate of atrazine concentrations from agricultural run-off using limited available information. The work discusses the methodology to develop the fuzzy rule base model using annual average use of herbicide atrazine per unit area, extent of herbicide atrazine applied area and herbicide atrazine application season as inputs to fuzzy rule based model and observed herbicide concentration at the basin outlet as the output for the fuzzy model. The data of White River Basin, a part of the Mississippi River system, USA, is used for developing the fuzzy rule base model.

### **2. Agricultural diffuse pollution concentration simulation in streams**

Natural and anthropogenic variables of stream drainage basins such as hydrogeologic parameters (permeability, porosity etc.), amount of agricultural chemicals applied, or percentage of land planted affect agricultural chemical concentration and mass transport in streams. The general form of model that simulates the concentration measurement in a watershed can be represented by (Tesfamichael et al., 2005)

$$\mathbf{C} = \mathbf{f} \text{ (W, H, A)}\tag{1}$$

where C is the stream agricultural diffuse pollution observed concentration measurement values; **W** is a vector of watershed characteristics; and **H** is a vector of hydrological variables such as precipitation, runoff, etc., and **A** is a vector of relevant agricultural practices including actual chemical application rate in the field in lb/acre.

For a particular watershed, watershed characteristic, **W**, may be assumed to be constant. Also, for a particular hydrological unit, **H** may be assumed to be of similar characteristics. Then, Equation (1), though simplified, may be represented by

$$\mathbf{C} = \mathbf{f} \begin{pmatrix} \mathbf{A} \end{pmatrix} \tag{2}$$

Prediction of Herbicides Concentration in Streams 231

statements and, therefore, the fuzzy logic is more in line with human perception (Zadeh, 2000). Fuzzy logic has an advantage over many statistical methods in that the performance of a fuzzy expert system is not dependent on the volume of historical data available. Since these expert systems produce a result based on logical linguistic rules, extreme data points in a small data set do not unduly influence these models. Because of these characteristics, fuzzy logic may be a more suitable method for diffuse pollution forecasting than the usual regression modeling techniques used by many researchers (e,g. Goolsby and Battaglin (1993); Larson and Gilliom (2001); and Tesfamichael et al. (2005) etc.) for estimation of

The most common way to represent human knowledge is to form it into natural language

The form in expression (4) is commonly referred to as the IF-THEN rule based form (Ross, 1997). It typically expresses an inference such that if a fact (premise, hypothesis, antecedent) is known, then another fact called a conclusion (consequent) can be inferred or derived. Fuzzy logic systems are rule base systems that implements a nonlinear mapping (Dadone and VanLandingham, 2000) between stresses (represented by consequents) and state variables (represented by antecedents). Creating a fuzzy rule based system may be summarized in four basic steps (Ross 1997; Mahabir et al. 2003; Singh and Singh 2005):

a. For each variable, whether an input variable or a result variable, a set of membership functions must be defined. A membership function defines the degree to which the value of a variable belongs to the group and is usually a linguistic term, such as high or

b. Statements, or rules, are defined that relate the membership functions of each variable

c. The rules are mathematically evaluated and the results are combined. Each rule is evaluated through a process called implication, and the results of all of the rules are

d. The resulting function is evaluated as a crisp number through a process called

Subjective decisions are frequently required in fuzzy logic modeling, particularly in defining the membership functions for variables. In cases such as in this study, where large data sets are not available to define every potential occurrence scenario for the fuzzification of model,

Membership functions used to describe linguistic knowledge are the enormously subjective and context dependent part of fuzzy logic modeling (Vadiee, 1993). Each variable must have membership functions, usually represented by linguistic terms, defined for the entire range of possible values. The key idea in fuzzy logic, in fact, is the allowance of partial belongings of any object to different subsets of universal set instead of belonging to a single set

to the result, normally through a series of IF–THEN statements.

combined in a process called aggregation.

expert opinion is used to create logic in the rule base system.

IF premise (antecedent), THEN conclusions (consequent) (4)

diffuse pollution concentration in streams or other water bodies.

**3.2.1 Fuzzy rule based system architecture**

expression of the type,

low.

defuzzification.

**3.2.2 Membership functions**

The **A** may be further represented by

$$\mathbf{A} = \mathbf{f} \left( \mathbf{A}\_{\mathbf{C},} \mathbf{A}\_{\mathbf{L}} \right) \tag{3}$$

where **AC** represent the vector of applied agricultural chemical characteristics such as type of agricultural chemical (insecticide, herbicides etc.), application rate, application season etc., and **AL** is the land use patterns such as type of crop grown, percentage of cropped area, etc.

Here, agricultural chemical considered is herbicide, atrazine, and crop considered is corn. In this study fuzzy rule based model with FCM simulates the stream system behavior from inputs of agricultural practices and corresponding observed concentration measurement values. In fact the model tries to emulate the mechanism that produced the data set. In this way, the mathematical description of the physical system is learned by the model, and therefore utilized as a tool for stream system simulation. The cluster centers of inputs and outputs obtained using FCM model, in essence, represents a typical characteristics of the system behaviour, and hence utilized in the formation of rule base of the fuzzy model.


**1. Introduction**

Selective laser melting (SLM) is an additive manufacturing method in which three-dimensional structures are formed by repeated melting and solidification of a metal powder by a laser [1]. SLM has been applied to various metal materials [2]. From a metallurgical perspective, the biggest advantage of SLM is that the cooling rate is much faster than that of the conventional casting method [3], and a characteristic microstructure is formed in the metals and alloys produced by SLM due to rapid solidification. In many studies, SLM has been applied to cast Al alloys containing 10–12% Si [4–9]. The microstructure of these alloys features a half-cylindrical melt pool [4,6] and a eutectic Si cellular structure [4–7] formed by quenching solidification due to the repeated laser scanning melting and solidification. This unique microstructure makes the room-temperature strength of SLM alloys higher than that of cast Al alloys [10,11] or Al alloys made by powder metallurgy [12]. The improvement of the room-temperature strength of Al alloys by SLM has been explained by the cellular structure of fine Si particles [12].

An important mechanical property for engine piston materials that are required to be lightweight to reduce inertia is high-temperature strength to withstand high pressure from combustion gases, even for small parts, as well as wear resistance. Heat-resistant cast Al alloys, obtained by adding an element such as Fe, Ni, Cu, or Mg to an Al–Si alloy near to the eutectic composition, are mainly used as a piston material in automobile engines. The demand for materials that retain their mechanical properties at high temperatures (250–350 ◦C) is increasing owing to the pressure to improve the efficiency and decrease the emissions of automobile engines. The high-temperature mechanical properties of Al alloys have been improved by optimizing the number of additional elements [13] or adding various elements, such as Mn, Ti, Zr, Sc, or Er, to existing heat-resistant Al alloys [14–16].

Fe is usually present in the Al alloy as an impurity. Fe is detrimental to the properties of cast Al alloys, but an Fe content of about 1 wt % or less is intentionally added to Al die-cast alloys to suppress die soldering [17]. If the cooling rate during casting is slow, the addition of Fe causes coarse plate-like β-Al5FeSi to crystallize, substantially decreasing toughness [18,19]. However, because Fe has a low di ffusion rate in Al, Fe-containing compounds can be used as a dispersion-strengthening phase at high temperatures. Al alloys produced by pressure sintering of rapidly solidified powders containing large amounts of Fe show excellent high-temperature strength [20,21]. Thus, if an extremely high cooling rate is achieved by SLM, it is expected that Al alloys with a high Fe content could be produced without ductility deterioration. Ma et al. [22] prepared an Al-20Si-5Fe-3Cu-1Mg alloy containing 5 wt % Fe by SLM and characterized its microstructure, although they did not evaluate the mechanical properties. In the present work, we used SLM to produce alloys obtained by adding 3–5 wt % Fe to existing heat-resistant Al alloys and evaluated their high-temperature mechanical properties in relation to the alloy microstructure on the conditions assuming application in engine piston materials.

## **2. Materials and Methods**

Table 1 shows the composition of the alloys prepared in this study. The chemical composition of these alloys was based on a conventional heat-resistant alloy AlSi-12CuNiMg (known as AC8A in Japan) and 3% or 5% Fe added to it (in this paper, all percentages for the chemical composition are wt % unless otherwise stated). The sample, equivalent to the chemical composition of the conventional alloy, is referred to as Base alloy, and the samples containing 3% or 5% Fe are referred to as Base + 3Fe or Base + 5Fe, respectively. The SLM alloy powders, which had a true spherical shape as shown in Figure 1, were prepared by atomization at Toyo Aluminium K.K (Hino, Japan). The compositions of the alloy powders are shown in Table 1.

**Table 1.** Chemical compositions of the alloys (wt %).

**Figure 1.** SEM image of the selective laser melting (SLM) powder of Base + 5Fe alloy.

An industrial three-dimensional printer (M280, EOS GmbH, Krailling, Germany) was used for SLM and the details of the manufacturing conditions are summarized in Table 2. Rectangular parallelepipeds of 10 mm × 10 mm × 40 mm or 80 mm (stacking height × width × length) were produced. The energy density, *E* (J/m3), was calculated by the following formula [23,24]:

$$E = \frac{P}{h\nu w} \tag{1}$$

where *P* (J/s) is the laser power, *h* (m) is the scan line spacing, *v* (m/s) is the scan rate, and *w* (m) is the single-layer thickness of the powder. The energy density is the amount of energy of the irradiation beam per unit volume applied to the powder material and is an important condition for producing a sound SLM body. Also, preheating of the substrate was also necessary to suppress destruction of the SLM body during SLM. The conditions summarized in Table 2 are values found to be optimal from prior examinations for producing the SLM bodies of the present alloy.

**Table 2.** Parameters of selective laser melting.

In AlSi-12CuNiMg (AC8A), which was the Base alloy in this work, Cu and Mg are added at 1%, so T6 treatment causes age hardening. When this alloy is practically applied to piston materials, it is used after T6 treatment. Therefore, we prepared a T6-treated sample for comparison with conventional materials. A piston material that is used at a high temperature of about 300 ◦C for a long time is required to have a stable microstructure at the temperature used. In addition, the rapidly solidified SLM material is a highly supersaturated solid solution (SSSS) in the as-built state. Elements are dissolved in the supersaturation precipitate during high-temperature holding, causing dimensional change of the SLM body. In the case of engine pistons, this causes serious problems. Therefore, annealing was performed at 300 ◦C in order to make the strength and dimensional changes less likely to occur when used for a long time at high temperatures by causing precipitation from an SSSS and growth of precipitates in advance.

Two series of samples with different heat-treatment sequences for the SLM bodies were prepared. In the first series, the samples were annealed at 300 ◦C after heat treatment equivalent to T6: 510 ◦C for 2 h (water quenching) followed by 170 ◦C for 4 h (air cooling). In the second series, the samples were annealed at 300 ◦C. The annealing details are described later. The first series of samples is called SLM-T6 and the second is called SLM-annealed. For comparison, two series of mold-cast samples made from Base alloy and Base + 3Fe alloy powders were prepared and subjected to the same heat-treatment sequences. The series subjected to T6 heat treatment is called cast-T6, and the series annealed at 300 ◦C is referred to as cast-annealed. The cast-T6 Base alloy was a sample equivalent to conventional AlSi-12CuNiMg alloy for practical use. All the samples were annealed at 300 ◦C for 10 h followed by air cooling before processing to a tensile test piece. The samples were sliced into flat plates 10 mm × 1.5 mm × 40 mm in size with the plate surface perpendicular to the stacking direction. Then, plates were punched into dog-bone-shaped test pieces with a length of 12 mm and a width of 4 mm for the gauge part. The bending caused by punching was smoothed by grinding. The rough surface of the as-produced SLM material was removed in the sample processing. To remove strain, the tensile test pieces were subjected to additional strain-relieving annealing at 300 ◦C for 2 h. The heat-treatment history of all the samples is summarized in Figure 2. The grain size of the SLM material after heat treatment was about 20 μm, regardless of the heat-treatment conditions.

The tensile test was carried out at 300 ◦C. The test piece was placed in an electric furnace, and after holding the furnace temperature at 300 ◦C for about 1 h, the tensile test was started at a strain rate of 6.9 × 10−3 s−1. The microstructures were characterized by observing the backscattered electron (BSE) images obtained by field-emission scanning electron microscopy (SEM; ULTRA 55, Carl Zeiss, Oberkochen, Germany) and the high-angle annular dark field (HAADF) images obtained

by scanning transmission electron microscopy (STEM; TITAN Cubed G2, FEI, Waltham, MA, USA). Element mapping by energy-dispersive X-ray spectroscopy (EDS) using STEM was also performed. The samples for the SEM observations were finished by colloidal silica polishing. Thin-film samples for the STEM observations were prepared by focused ion beam microsampling.

**Figure 2.** Heat-treatment history of (**a**) SLM-T6 and cast-T6 and (**b**) SLM-annealed and cast-annealed.

## **3. Results and Discussion**

Figure 3 shows the true stress–true strain curves of the SLM-annealed, cast-annealed, SLM-T6, and cast-T6 materials at 300 ◦C. The ultimate tensile strength (UTS) of the SLM-annealed Base alloy was 77 MPa and the elongation to fracture (EL) was about 31%. On the other hand, the UTS and the EL for the cast-annealed Base alloy were 67 MPa and 11%, respectively. The alloy produced by SLM had good ductility but did not differ much from the cast material in high-temperature strength. However, the SLM-annealed Fe-containing alloys showed higher UTS than the SLM-annealed Base alloy at 300 ◦C. The UTS of the SLM-annealed Base + 3Fe and Base + 5Fe alloys at 300 ◦C were 165 and 185 MPa, respectively. The UTS increased with the amount of Fe. The UTS of the cast-T6 Base alloy, which can be considered as the conventional AlSi-12CuNiMg alloy, was 94 MPa. The UTS of the SLM-annealed Base + 5 Fe alloy at 300 ◦C reached about twice that of the cast-T6 Base alloy. The high-temperature strength of the Base alloy produced by casting was increased by the T6 heat treatment. In contrast, for alloys made with SLM, T6 heat treatment caused a reduction in strength. This deterioration of the UTS was remarkable in the Fe-containing alloys.

The UTS and the EL at 300 ◦C of the sample prepared in this study and the novel cast Al alloys recently reported [25–28] are summarized in Table 3. The UTS at 300 ◦C of the Fe-added SLM alloys was comparable to that of novel cast Al alloys, the strength of which is improved by the addition of Sr, Ti, Zr, and V. However, it should be noted that UTS at high temperatures depends on the strain rate. Since the strain rate in this study was larger than the literature value, it was considered that UTS was evaluated somewhat higher. The elongation to fracture of the SLM-annealed Base + 3Fe and Base + 5Fe alloy at 300 ◦C was 20% and 24%, respectively, values which were larger than those of the cast-T6 Base alloy or other novel cast Al alloys [25,26]. The cast Fe-containing alloys were so brittle that the specimens were destroyed when the they were punched; thus, the tensile test could not be performed for these materials. When a large amount of Fe is added to cast Al alloys, the coarse plate-shaped β-Al5FeSi phase crystallizes out. Pores are formed in the material because the molten metal cannot fill the region surrounding the coarse plate-shaped particles [29], and the toughness is degraded. The Fe-containing alloys produced by SLM showed elongation to fracture of at least 20% at 300 ◦C. Thus, using SLM allowed Fe to be added without impairing toughness. In general, there is

a trade-off between strength and ductility. However, the SLM-annealed Base + 3Fe and Base + 5Fe alloys had high strength and ductility. That is, a material which has a good strength-ductility balance can be produced by using SLM. Similar results have been reported in previous studies and have been explained by the microstructure specific to SLM [11,30].

**Figure 3.** True stress-true strain curves of the SLM material and cast material at 300 ◦C for (**a**) SLM-annealed and cast-annealed and (**b**) SLM-T6 and cast-T6.

Using SLM with the Base alloy did not dramatically increase the high-temperature strength; however, the Base + 3Fe and Base + 5Fe alloys were strengthened by SLM because of the addition of Fe. The microstructures of these alloys were observed to reveal the reason for the remarkable strengthening by Fe addition. Figure 4 shows the SEM-BSE images of alloys prepared by casting and SLM. In Figure 4, it should be noted that the cast and SLM materials have different scales. In the cast-annealed Base alloy, coarse particles of Chinese script shape or rod shape were observed. These particles were further coarsened by T6 treatment. In the SLM-annealed materials, second-phase particle cells were observed. In the Base alloy, there was a small amount of bright equiaxed particles, whereas in the Fe-containing alloys, there was a large amount of bright rod-shaped particles. In the SLM-T6 materials, both bright equiaxed particles and bright rod-shaped particles were coarsened and no cellular structure was observed.

Figure 5 shows the STEM-EDS mapping of the constituent elements of the second-phase particles in the SLM-annealed Base and Base + 3Fe alloys. In the SLM-annealed Base alloy, Si, Mg, and Cu-Ni particles formed a cellular structure. In the SLM-annealed Base + 3Fe alloy, in addition to these particles, there were many rod-shaped particles consisting mainly of Fe, Si, and Ni. In the EDS element map, particles only enriched with Si were eutectic Si. Eutectic Si is present in cells formed in the Al-Si binary alloy produced by additive manufacturing [4–7]. In the SEM-BSE images (Figure 4), the particles that were slightly brighter than the Al matrix corresponded to eutectic Si. The Si particles in the SLM-annealed materials were about 200 nm in size, whereas the particles were coarsened to several micrometers in the SLM-T6 materials. The bright, equiaxed particles in the SEM-BSE images of the Base

alloy were Cu-Ni particles. Based on the EDS element map, the Fe-Si-Ni particles in the SLM-annealed Base + 3Fe alloy were characteristic rod-shaped particles with a width of 100 nm or less and a length of several hundred nanometers. Based on the shape of the particles, the bright rod-shaped particles in the SEM-BSE images of the Fe-containing alloys corresponded to these Fe-Si-Ni particles.

**Figure 4.** SEM-backscattered electron (BSE) images of cast and SLM alloys. (**a**) Cast-annealed Base, (**b**) SLM-annealed Base, (**c**) SLM-annealed Base + 3Fe, and (**d**) SLM-annealed Base + 5Fe, (**e**) Cast-T6 Base, (**f**) SLM-T6 Base, (**g**) SLM-T6 Base + 3Fe, and (**h**) SLM-T6 Base + 5Fe alloys.

**Figure 5.** Scanning transmission electron microscopy–high-angle annular dark field (STEM-HAADF) images and corresponding energy-dispersive X-ray spectroscopy (EDS) element maps for (**a**) SLM-annealed Base and (**b**) SLM-annealed Base + 3Fe.

The Fe-Si-Ni particles in the Base + 3Fe alloy were finer than those in the Base + 5Fe alloy. Similar to the Si particles, the rod-shaped Fe-Si-Ni particles were coarsened by T6 treatment. T6 treatment coarsened the Si particles and destroyed the cellular structure of Si characteristic of the SLM materials. However, as shown in Figure 3, the UTS at 300 ◦C of the SLM-annealed Base alloy and SLM-T6 Base alloy were 77 and 69 MPa, respectively, which were not significantly di fferent. Therefore, in contrast to the room-temperature strength [12], the cell structure of the Si particles did not contribute to an increase in high-temperature strength. This is also clear from that the UTS of the Base alloys produced by SLM and casting were almost the same in annealed condition. The ductility of the SLM-T6 Base alloy was improved compared with the cast Base alloys, though both alloys contained coarse Si particles. The Si particles in the SLM material that exhibited good ductility had an equiaxed shape, whereas those of the cast material had a Chinese script shape or rod shape. Therefore, it is considered that the equiaxial shape of the Si particles contributed to the improvement of the ductility of the SLM material.

In contrast to the Base alloy, the UTSs of the SLM-T6 Base + 3Fe and Base + 5Fe alloys at 300 ◦C were about 40% lower than the corresponding SLM-annealed alloys. The T6 treatment coarsened the Si and Fe-Si-Ni particles in the Fe-containing alloys. Because the high-temperature strength did not increase only with the fine cellular Si particles, we concluded that the fine dispersion of rod-shaped Fe-Si-Ni particles was the main reason that the SLM-annealed Base + 3Fe and Base + 5Fe alloys had excellent high-temperature strength. These fine particles were present even after annealing at 300 ◦C for 12 h; thus, they were stable at temperatures up to 300 ◦C and were useful for dispersion strengthening at high temperatures. In the annealed material, the rod-shaped Fe-Si-Ni particles formed cells together with Si particles. In future research, we intend to examine the e ffects of cellular particle distribution and cellular morphology on high-temperature strength.


**Abstract**

Traditional cheeses represent by themselves high-quality productions that are expressions of a production system highly linked to the territory. Biodiversity factors rising from the natural system have been extensively studied, and their effect on the quality of dairy products has been scientifically shown. CoRFiLaC is among the main contributors to this field with many studies developed on traditional productions in different environments. The main goal of the chapter is to highlight through case studies the methods applied in scientific protocols in order to define, besides the identification of biodiversity factors affecting quality, and valorize health properties and safety aspects and to understand consumer reactions and intentions to purchase depending on specific characteristics of final products. The combination of research performed in every single aspect of traditional production is the real challenge and good strategy to valorize highquality goods.

**Keywords:** biodiversity, consumer expectations, traditional products, marketing


**4.5 Heavy metals inhibition**

Heavy metals are present in various types of wastewater, including agro-industrial wastewater, landfill leachate and cane vinasses (Del Real et al., 2009; Yusof et al., 2009). Although many metals are required in trace amounts to provide sufficient growth to methanogens, the methanogenic activity in anaerobic reactors is strongly affected by excess amounts of heavy metals (Colussi et al., 2009). The toxic effects of metals in biological process is particularly due to the inhibition of enzymes activity as a result of metals binding to the SH group of the enzyme. The inhibitory concentrations of four heavy metals on methane-producing granular sludge that caused 50% reduction in cumulative methane production was found to be 7.5 mg/L of Zn, 27 mg/L of Cr, 35 mg/L of Ni and 36 mg/L of Cd with an order of Zn>Cr>Ni≈Cd (Altas, 2009). Whereas a different study revealed that 50% reduction in methane production occurred at 6.4 mg/L of Cu (II), 4.4 mg/L of Cd(II) and 18.0 mg/L of Cr(VI) with an order of Cd(II)>Cu(II)>Cr(VI) in anaerobic digestion of cattail with rumen culture (Yue et al., 2007).

Yue and coworker in 2007, indicated that metals cause anaerobic system failures when they are in the form of free ions (in its soluble form) and above certain concentrations (Table 3). The differences reported in the metals inhibitory concentration might be due to the several factors including variation in sludge characteristics, chemical form of heavy metals and microbial resistance to metals (Altas, 2009). Various heavy metals presence in wastewater

1950):

**6. Reactor types**

Biogas Production from Anaerobic Treatment of Agro-Industrial Wastewater 103

The volumetric measurement of biogas must compensate the pressure and temperature differences. The equation 10, illustrate a simple method of gas volume compensation for a saturated gas taking into account the adjustment by pressure and temperature (Salisbury,

V� = V ∗ 17.626 ∗ �����

where *V* is the observed volume, *Vs* volume at standard conditions (60°F and 30 inches Hg), *H* is absolute gas pressure (inches Hg), *A* water vapor pressure (inches Hg), and *T* temperature of gas (°F). Pure methane at standard temperature and pressure has a lower heating value of 912 BTU/ft3 (34 kJ/L). Typical biogas of 65% methane has a heating value of approximately 600 BTU/ft3 (22.36 kJ/L), since only the methane portion will burn,

> **Biogas with 65% of methane (1000 L)**  600 L of natural gas 25.0 L of propane 22.3 L of Butane 17.79 L of gasoline 16.28 L of diesel

Many reactor configurations are used for the anaerobic treatment of agro-industrial wastewaters. Among them, the most common types are discussed and illustrated in Fig. 2.

Fig. 2. Most commonly used anaerobic reactors types: (A) Completely mixed anaerobic digester, (B) UASB reactor, (C) AFB reactor, (D) Upflow AF reactor (Ersahin et al., 2011)

The completely stirred anaerobic digester (CSTR) is the basic anaerobic treatment system with an equal hydraulic retention time (HRT) and solids retention time (SRT) in the range of 15-40 days in order to provide sufficient retention time for both operation and process stability. Completely mixed anaerobic digesters without recycle are more suitable for wastes with high solids concentrations (Tchobanoglous et al., 2003). A disadvantage of this system

approximate equivalents of biogas to others fuels are presented in the table 5.

Table 5. Equivalents of biogas others fuels (Palmer, 1981)

**6.1 Completely stirred anaerobic digester**

����.���� (10)

also showed synergistic effects during anaerobic treatment process. For instance, the presence of chromium in the sludge results in higher toxicity of copper (Colussi et al., 2009).

Altas in 2009 showed that low concentrations of metals in the anaerobic reactor can be extremely toxic. Meanwhile, Cantrell and coworkers (2008) indicated that high concentrations of soluble metals have come to completely stop the production of biogas in an anaerobic system. To combat metal toxicity in the anaerobic degradation process, they can be precipitated as sulphate salts and carbonate salts, except iron and chromium.

Table 3. Concentrations of inorganic compounds inhibitory of anaerobic process (Yue *et al.*, 2007).


Author details

Another genome editing system that has recently gained attention in research and clinical application is CRISPR/Cas9 system. The CRISPR/Cas9 system is based on CRISPR (clustered regularly interspaced short palindromic repeats) sequence and CRISPR associated (Cas) gene mechanism that are crucial for innate defense mechanism in bacteria and archaea enabling the organisms to respond to and eliminate invading genetic materials from their phages [132]. The CRISPR/Cas9 system consists of two key molecules that introduce a mutation into the DNA. First, Cas9 is an enzyme that acts as a pair of DNA scissor. It cuts the two strands of DNA at a specific location in the genome so the genome editing could be performed either addition or removal. The other molecule is guide RNA (gRNA) which consists of a small piece of predesigned RNA sequence (20 bases long) located within a long RNA scaffold. The long RNA scaffold binds to DNA and the gRNA sequence guides Cas9 to edit the specific part of genome. gRNA sequence is designed to be complementary to the target DNA sequence in the target gene in the genome. gRNA sequence consists of short palindromic repeats and the sequences that complement with the target genes. The target sequences should be present close to protospacer adjacent motif (PAM) sequence which increases the specificity of Cas9. After Cas9 nuclease enzyme site specifically cleaves double stranded DNA activating double-strand break repair machinery. If the DNA repair template is provided, the piece of DNA repair template will be inserted into the sequence of target genes [133, 134]. With this mechanism, the plasmid containing gRNA, Cas9 sequences, TracrRNA (transactivating CRISP RNA) and DNA repair template sequence can be introduced into cells or embryo of the animals by viral or nonviral delivery system [135]. Until now, there is no CRISPR/Cas9 experiment involving orthodontic tooth movement, however, this technology has been implemented in recent mineralized tissue research [136–139]. Future directions of gene therapy include the enhancement of the lentiviral vector-based approaches, fine tuning of the conditioning regimen, and the design of safer vectors or nonviral vector delivery system. In orthodontic field, the gene therapy approach will need several fundamental cell culture and animal experiments to demonstrate the safety and efficacy of the treatment concept. Clinical trials are required as the next step to ascertain the

We would like to acknowledge Ms. Pornpasdchanok Asawasuwan for all artworks in the manuscript. This manuscript was supported by ROAAP fund, the University of Illinois at Chicago, Brodie Craniofacial Endowment fund, and the National Institute of Dental and Craniofacial

clinicians and patients for efficacy of the treatments.

Acknowledgements

62 Current Approaches in Orthodontics

Research (DE024531).

Conflict of interest

The authors declare no conflict of interest.

Phimon Atsawasuwan1 \* and Sajjad Shirazi2,3

\*Address all correspondence to<EMAIL_ADDRESS>
1 Department of Orthodontics, University of Illinois at Chicago, Chicago, Illinois, United States


**Author details**

Księżak Jerzy and Bojarszczuk Jolanta\* Department of Forage Crop Production, Institute of Soil Science and Plant Cultivation—State Research Institute, Puławy, Poland

\*Address all correspondence to<EMAIL_ADDRESS>
© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**77**

*The Productivity of Selected Species and Cultivars of Legumes Grown for Seeds in Organic…*

Chemical composition, functional properties and protein characterization.

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[10] Duranti M, Consonni A, Magni C, Sessa F, Scarafoni A. The major proteins of lupin seed: Characterization and molecular properties for use as functional and nutraceutical ingredients. Food Science and Technology. 2008;**19**:624

[11] Small E. Lupines—Benefit and harm potentials. Biodiversity. 2012;**13**:54

[12] Doležal P, Zeman L, Skládanka J. Effect of supplementation of chemical preservatives on fermentation process of lupine silage. Slovak Journal of Animal

[13] Fraszer MD, Fychan R, Jones R. Comparative yield and chemical composition of two varieties of narrowleafed lupin (*Lupinus angustifolius*) when harvested as whole-crop, moist grain and dry grain. Animal Feed Science and Technology. 2005;**120**:43-50

[14] Szyszkowska A, Bodarski R, Sowiński J, Załęska A. The possibilities

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*DOI: http://dx.doi.org/10.5772/intechopen.82686*

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*The Productivity of Selected Species and Cultivars of Legumes Grown for Seeds in Organic… DOI: http://dx.doi.org/10.5772/intechopen.82686*


*6.1.1 Mechanism*

A proposed mechanism for the protective properties of calcium against CRC is its ability to bind to unconjugated bile acids and free fatty acids (FFAs), thereby limiting their toxic effects on the colorectum [4, 61]. Cell culture studies suggest that it may also suppress cell proliferation and promote cell differentiation and

apoptosis, likely by influencing different cell-signaling pathways [4, 62]. Calcium may also prevent colonic K-ras mutations and inhibit haem-induced promotion of colon carcinogenesis [63, 64]. In addition, calcium also inhibits oxidative DNA damage and modulates CRC-related cell-signaling pathways [4].


**Ahmad Neyaz Khan 1,\*, Ming Yu Fan 1,\*, Muhammad Irshad Nazeer 2, Raheel Ahmed Memon 2, Asad Malik 3 and Mohammed Aslam Husain 4**

Received: 23 April 2019; Accepted: 3 June 2019; Published: 17 June 2019

**Abstract:** Reversible data hiding in encrypted image (RDHEI) is advantageous to scenarios where complete recovery of the original cover image and additional data are required. In some of the existing RDHEI schemes, the image pre-processing step involved is an overhead for the resource-constrained devices on the sender's side. In this paper, an efficient separable reversible data hiding scheme over a homomorphically encrypted image that assures privacy preservation of the contents in the cloud environment is proposed. This proposed scheme comprises three stakeholders: content-owner, data hider, and receiver. Initially, the content-owner encrypts the original image and sends the encrypted image to the data hider. The data hider embeds the encrypted additional data into the encrypted image and then sends the marked encrypted image to the receiver. On the receiver's side, both additional data and the original image are extracted in a separable manner, i.e., additional data and the original image are extracted independently and completely from the marked encrypted image. The present scheme uses public key cryptography and facilitates the encryption of the original image on the content-owner side, without any pre-processing step involved. In addition, our experiment used distinct images to demonstrate the image-independency and the obtained results show high embedding rate where the peak signal noise ratio (PSNR) is +∞ dB for the directly decrypted image. Finally, a comparison is drawn, which shows that the proposed scheme is an optimized approach for resource-constrained devices as it omits the image pre-processing step.

**Keywords:** reversible data hiding (RDH); image processing; cloud computing; public key cryptography (PKC); security


**Mohamed A. Tahoon 1, Saifeldin M. Siddeeg 1,2, Norah Salem Alsaiari 3, Wissem Mnif 4,5 and Faouzi Ben Rebah 1,6,\***

Received: 22 April 2020; Accepted: 23 May 2020; Published: 29 May 2020

**Abstract:** The discharge of toxic heavy metals including zinc (Zn), nickel (Ni), lead (Pb), copper (Cu), chromium (Cr), and cadmium (Cd) in water above the permissible limits causes high threat to the surrounding environment. Because of their toxicity, heavy metals greatly affect the human health and the environment. Recently, better remediation techniques were offered using the nanotechnology and nanomaterials. The attentions were directed toward cost-effective and new fabricated nanomaterials for the application in water/wastewater remediation, such as zeolite, carbonaceous, polymer based, chitosan, ferrite, magnetic, metal oxide, bimetallic, metallic, etc. This review focused on the synthesis and capacity of various nanoadsorbent materials for the elimination of different toxic ions, with discussion of the effect of their functionalization on the adsorption capacity and separation process. Additionally, the effect of various experimental physicochemical factors on heavy metals adsorption, such as ionic strength, initial ion concentration, temperature, contact time, adsorbent dose, and pH was discussed.

**Keywords:** water treatment; nanomaterials; heavy metals; functionalization


**1. Introduction**

High-entropy alloys (HEAs) are known for their special mechanical properties: high tensile strength resistance even at high temperature, high hardness, toughness exceeding that of most pure metals and alloys, comparable strength to that of structural ceramics and some metallic glasses, exceptional ductility and fracture toughness at cryogenic temperatures, and corrosion resistance. These specific properties were mainly attributed to complex concentrated solid solutions formed by the suppression of fragile intermetallic compounds as a result of high mixing entropy and enthalpy values [1]. HEAs generally tend to form single-phase solid solutions in the case of low mixing enthalpy and atomic size difference. Generally speaking, the formation of a single-phase solid solution corresponds to the mixing enthalpy values (DHmix) situated in domain of −15 kJ/mol < DHmix <5 kJ/ml and 0 < δ < 5 [2].

As a result of these special features, HEA is currently an alternative to use as material for a number of special areas, such as structural applications; aerospace engineering and civil transportations; superconducting electromagnets such as magnetic resonance imaging, scanners, nuclear magnetic resonance machines, and particle accelerators; high-temperature applications such as gas turbines, rocket nozzles, and nuclear construction; cryogenic applications such as rocket casings, pipework, and liquid O2 or N2 equipment; refractory elements such as Nb, Mo, and Ta that can maintain their high strength even above 1200°C, superior to traditional super alloys such as Inconel 718 and Haynes 230; hardfacing applications; and military applications.

The specifications on the security of collective protection equipment and structures in the military field set forth enhanced requirements for the resistance of the protection panels/floors/elements against the penetration by various types of projectiles, due to the diversification of the types of interventions in the military activities.

The main characteristics of the materials intended for the manufacture of protection components are as follows: the highest possible breaking and yield strength values, the highest possible hardness and impact resistance, and the highest possible elongation at break and energy absorbed by a notched specimen while breaking under an impact load (the Charpy test) at temperatures down to minus 40°C. The current military specifications recommend hardness values of at least 540–600 BHN (Brinell hardness) or 55–60 HRC (Rockwell hardness) and, for strength characteristics, such as the yield strength, values above 1500 and 1700 MPa for the breaking strength. In the case of the impact fracture energy using the Charpy test, the values must be of approximately 13 J at −40°C, with elongations of at least 6% [3].

Such requirements have been met by designing metallic alloys of various compositions; the most widely used is the high-strength microalloyed steels, used to produce reinforcement elements of thicknesses between 8.5 and 30 mm. Some research papers in the military field [4] have shown that the hardness of the plating material is not a sufficient factor to provide maximum resistance against penetration by projectiles, considering that the values of the mechanical strengths (yield and breaking) are much more important in the behavior process under dynamic stress.

Accurate measurements of dynamic stresses during impact stress have detected mechanical stress values of 28 GPa in the case of bainitic microstructure steels, while in the case of static stress, the measured stresses were of no more than 2 GPa [5].

A ballistic performance index (BPI) [6, 7] was also proposed to estimate the ballistic strength of armored plates, containing data on steel density, the elastic modulus, yield and tensile strength, Poisson's coefficient, and the constriction or elongation during impact tests. There are terms that contain elastic and plastic deformation components, as well as terms that take into account the kinetic energy of the target-projectile system after impact. Therefore, the main characteristics that

**141**

*Characterization and Testing of High-Entropy Alloys from AlCrFeCoNi System for Military…*

metallic materials used in special military applications need to feature for the best

• The highest possible hardness, as a measurement of the solid material's resistance against the penetration of its surface by various types of penetrators, with permanent shape changes, when a static or dynamic force is applied to them; the macroscopic hardness is generally characterized by the nature and strength of the intermolecular bonds, and the behavior of the solid material

• Toughness, which describes the capacity of a metallic material to absorb the breaking energy, the strength of its metallic matrix when various cracks occur and propagate, and the energy of forming the breaking surfaces, considering that the breaking occurs by consuming the impact stress energy, with local

• Impact strength, which is the relative susceptibility to breaking by the action

High-entropy alloys from the AlCrFeCoNi system feature very good mechanical properties for military applications, as shown in **Table 1**. Thus, the yield stress, the compressive strength, and the plastic deformation of these alloys reach unexpected values [8–20], making them usable as composite structures, resistant to dynamic stresses with high deformation velocity, applicable in the field of collective protection [9–20].

The most commonly used method for successfully producing high-entropy alloys is the electric arc melting of the load materials in a vacuum arc remelting equipment (with current values of up to 500 A) in controlled atmosphere. The main

Special type of materials chosen for making the ballistic target is experimental alloys AlCrFeCoNi, obtained in vacuum arc remelting equipment (MRF ABJ 900, in ERAMET Laboratory, University Politehnica of Bucharest, Romania). For calculating the metallic load, the theoretical degrees of assimilation of the elements in the melt and of the possible vaporization losses during the metallurgical process in vacuum or in argon-controlled atmosphere must be taken into account (**Figure 1**). Mass losses are estimated on the basis of the literature data thereon, the degree of oxidation of the metallic load materials, the characteristics of the elements in the load, their positioning in the series of electrochemical potentials, the characteristics of the preparation aggregate, and the experience in the preparation process. It should be noted that the metallic load used to obtain high-entropy alloys must be of high quality, low in phosphorus and sulfur, and degreased and properly machined (in terms of granulometry). The degree of purity of the elements the alloy is over 99%. The elements dosed in equimolecular or quasi-equimolecular proportions are introduced following an order determined according to the type of alloy to be prepared, into the crucibles in the copper plate, water-cooled throughout the metallurgical process. In order to produce high-entropy alloys under high-purity conditions, the working chamber must be suitably prepared by successive vacuuming and argon purging

**2. Obtaining of AlxCryFezCovNiw class of high-entropy alloys**

technological operations pursued in this case are presented below.

**2.1 Obtaining AlCrFeCoNi alloys in vacuum arc remelting furnace**

*DOI: http://dx.doi.org/10.5772/intechopen.88622*

under the action of force is complex.

of forces applied at high velocity.

impact behavior are as follows:

plastic deformation.

#### **Table 1.**

*Mechanical properties of some high-entropy alloys [8].*

*Characterization and Testing of High-Entropy Alloys from AlCrFeCoNi System for Military… DOI: http://dx.doi.org/10.5772/intechopen.88622*

metallic materials used in special military applications need to feature for the best impact behavior are as follows:

High-entropy alloys from the AlCrFeCoNi system feature very good mechanical properties for military applications, as shown in **Table 1**. Thus, the yield stress, the compressive strength, and the plastic deformation of these alloys reach unexpected values [8–20], making them usable as composite structures, resistant to dynamic stresses with high deformation velocity, applicable in the field of collective protection [9–20].


**2.** *In vivo* **experimental systems**

Mice provide a model system to distinguish characteristics of disease between autoimmune myocarditis and viral myocarditis. Mice are advantageous models because they share similar genetics to humans, they are cost-effective in handling and breeding, many transgenic strains are available and they are responsive to cardiotropic viruses (Cunningham 2001; Fairweather et al. 2001; Esfandiarei et al. 2008). Coxsackievirus B3 has been detected in 30-50% of dilated cardiomyopathy patients, providing support for a coxsackievirus B3-induced myocarditis mouse model (Escher et al. 2011). Following a single dose of coxsackievirus B3, acute myocarditis, encephalomeningitis, hepatitis, and even pancreatitis can ensue. Severe systemic pathogenicity observed with coxsackievirus B3 infection has also been related to the presence of sarcoma (Src) family kinase Lck (p56lck) (Liu et al. 2000). With coxsackievirus B3 infection, mice tend to either develop chronic dilated cardiomyopathy mirroring clinical disease after recovering from viral infection or mice die from severe cytopathic effects, thus making coxsackievirus B3-induced myocarditis an excellent yet challenging model to study (Liu et al. 2000).

Studies with mice have demonstrated the significant contribution of the Th1 immune response to disease severity even though coxsackievirus B3 directly targets and destroys the myocardium. The contribution of a Th1 response to viral myocarditis pathogenesis is supported by studies modulating and inhibiting immune components and improving cardiac damage and function (Jiang et al. 2008).

Interestingly and in parallel with human myocarditis, male mice infected with coxsackievirus B3 experience acute myocarditis with greater severity compared to females. Greater disease severity in males has been linked to enhanced cardiac and splenic mast cell and macrophage TLR-4 expression at 12 hours post-infection (Frisancho-Kiss et al. 2006; Frisancho-Kiss et al. 2007). In males virally infected, signalling through cardiac TLR-4 enhances the production of cardiac IL-1β and IL-18 and promotes a Th1 skewed immune response (Fairweather et al. 2003). Also, male mice infected with coxsackievirus B3 harbour macrophages of a different phenotype and have more severe disease compared to infected female mice though viral replication is at similar levels in the heart (Frisancho-Kiss et al. 2006; Frisancho-Kiss et al. 2007). Moreover, genes relating to cholesterol metabolism in macrophages and to androgen receptor, which are known predictors for myocarditis, dilated cardiomyopathy and heart failure in male mice and humans, are upregulated considerably in spleens of male mice (Onyimba et al. 2011). This not only affords support for a gender difference in the susceptibility to viral-myocarditis, but critically implicates the innate response in disease severity. Furthermore, to bring male mice to the same immunological plane as female mice during myocarditis, Frisancho-Kiss et al removed the gonads from BALB/c mice and observed an increase in IL-4 production, the activation of macrophages and induction of regulatory T cells in the heart (Frisancho-Kiss et al. 2009).

Myocarditis can be induced in female mice with TNF-α treatment on days 1 and 3 post coxsackievirus B3 infection (Huber 2010). The lack of disease susceptibility in females is

protein 2B (van Kuppeveld et al. 1997; Esfandiarei et al. 2008). Though many groups have identified key virus and host interactions throughout the coxsackievirus B life cycle, there still remains many stages unsolved. Nevertheless, the role of coxsackievirus B in the onset of myocarditis has been extensively studied thus far in animal models and cell culture systems. Here, we will discuss clinical and mouse studies that have investigated coxsackievirus-

Mice provide a model system to distinguish characteristics of disease between autoimmune myocarditis and viral myocarditis. Mice are advantageous models because they share similar genetics to humans, they are cost-effective in handling and breeding, many transgenic strains are available and they are responsive to cardiotropic viruses (Cunningham 2001; Fairweather et al. 2001; Esfandiarei et al. 2008). Coxsackievirus B3 has been detected in 30-50% of dilated cardiomyopathy patients, providing support for a coxsackievirus B3-induced myocarditis mouse model (Escher et al. 2011). Following a single dose of coxsackievirus B3, acute myocarditis, encephalomeningitis, hepatitis, and even pancreatitis can ensue. Severe systemic pathogenicity observed with coxsackievirus B3 infection has also been related to the presence of sarcoma (Src) family kinase Lck (p56lck) (Liu et al. 2000). With coxsackievirus B3 infection, mice tend to either develop chronic dilated cardiomyopathy mirroring clinical disease after recovering from viral infection or mice die from severe cytopathic effects, thus making coxsackievirus B3-induced myocarditis

Studies with mice have demonstrated the significant contribution of the Th1 immune response to disease severity even though coxsackievirus B3 directly targets and destroys the myocardium. The contribution of a Th1 response to viral myocarditis pathogenesis is supported by studies modulating and inhibiting immune components and improving

Interestingly and in parallel with human myocarditis, male mice infected with coxsackievirus B3 experience acute myocarditis with greater severity compared to females. Greater disease severity in males has been linked to enhanced cardiac and splenic mast cell and macrophage TLR-4 expression at 12 hours post-infection (Frisancho-Kiss et al. 2006; Frisancho-Kiss et al. 2007). In males virally infected, signalling through cardiac TLR-4 enhances the production of cardiac IL-1β and IL-18 and promotes a Th1 skewed immune response (Fairweather et al. 2003). Also, male mice infected with coxsackievirus B3 harbour macrophages of a different phenotype and have more severe disease compared to infected female mice though viral replication is at similar levels in the heart (Frisancho-Kiss et al. 2006; Frisancho-Kiss et al. 2007). Moreover, genes relating to cholesterol metabolism in macrophages and to androgen receptor, which are known predictors for myocarditis, dilated cardiomyopathy and heart failure in male mice and humans, are upregulated considerably in spleens of male mice (Onyimba et al. 2011). This not only affords support for a gender difference in the susceptibility to viral-myocarditis, but critically implicates the innate response in disease severity. Furthermore, to bring male mice to the same immunological plane as female mice during myocarditis, Frisancho-Kiss et al removed the gonads from BALB/c mice and observed an increase in IL-4 production, the activation of macrophages and induction of regulatory T cells in the heart (Frisancho-Kiss et al. 2009). Myocarditis can be induced in female mice with TNF-α treatment on days 1 and 3 post coxsackievirus B3 infection (Huber 2010). The lack of disease susceptibility in females is

induced myocarditis and the role of key immune players in disease pathogenesis.

**2.** *In vivo* **experimental systems**

an excellent yet challenging model to study (Liu et al. 2000).

cardiac damage and function (Jiang et al. 2008).

attributed to low mRNA and protein levels of TNF-α and IL-Iβ as well as reduced CD1d expression on splenic lymphocytes. CD1d is an important non-classical major histocompatibility complex antigen that can be regulated by TNF-α to induce myocarditis susceptibility in female mice (Huber 2010).

Not only is susceptibility to developing myocarditis dictating by sex, but development of chronic disease depends on the mouse strain. A.BY/SnJ & SWR/J are susceptible mouse strains that can develop ongoing myocarditis, where viral RNA is detected within the myocardium. C57BL/6J & DBA/1J mice are resistant strains capable of eliminating virus just after the early acute phase of disease. Tomioka and colleagues investigated neutralizing antibodies and their role in virus-induced myocarditis and B-cell-mediated immunity using BALB/c mice (Esfandiarei et al. 2008). NK-deficient mice have been used to look at the role of natural killer (NK) cells in killing virus-infected cardiomyocytes (Godeny et al. 1986). Perforin knockout mice inoculated with coxsackievirus B3 have also been used to describe the interplay of virus infection and lymphocyte infiltration in the myocytes and their effect on disease outcome (Godeny et al. 1987). Interestingly, with coxsackievirus B3 infection in suckling, weaning and adolescent mice, coxsackievirus B3 replicates in the heart, pancreas, spleen, and brain and causes human disease-like symptoms. In fact, following IP injection, three distinct immunovirological phases of disease have been observed.

In mice, coxsackievirus B3 can induce two forms of inflammatory heart disease, acute only or acute and chronic (biphasic) autoimmune disease (Horwitz et al. 2000; Cunningham 2001; Fairweather et al. 2001). Interestingly, coxsackievirus B3 replication is mainly observed in the pancreas and to a lesser extent in the heart. In genetically susceptible mice, such as A/J2, Balb/c and NOD mice, chronic autoimmune myocarditis after coxsackievirus B3 infection is observed. Autoimmune myocarditis in mice presents as early as day 7 pi with inflammatory cell infiltration in the heart and the formation of multifocal inflammatory lesions. At this stage, autoantibodies (autoAbs) against heart antigens, like cardiac myosin (cardiac myosin), are seen. In NOD mice, isotype switching ensues after 2 to 3 weeks, with the autoAbs switching from IgM to IgG subclasses (Kaya et al. 2001; Kaya et al. 2002). It is particularly remarkable to note that the chronic autoimmune heart disease induced by coxsackievirus B3 in mice resembles inflammatory heart disease seen with myocarditis and dilated cardiomyopathy in humans. There are still many complications with the full characterization and study of chronic virus and/or autoimmune induced myocarditis in mice and humans. One such complication is the acute infection that precedes chronic disease.