**2. Materials and Methods**

Suppose our observed data are collected from *N* subjects. For subject *i*, we use a *p* dimensional vector **x***i* = (*xi*1, *xi*2, ... , *xip*) to denote the normalized gene expression profile and *yi* ∈ {1, −1} to denote its class label. Similarly, the gene expression levels of a given pathway *m* with *pm* genes can be represented by **x** (*m*) *i* = (**x** (*m*) *i*1 , **x** (*m*) *i*2 ,..., **x** (*m*) *ipm* ), which is a sub-vector of **x***i*.

The log loss function is commonly used in binary classifications with the following form:

$$d(y, F(\mathbf{x})) = \log(1 + e^{-yF(\mathbf{x})}),$$

and is minimized by

$$F^\*(\mathbf{x}) = \log \frac{p(y=1|\mathbf{x})}{p(y=-1|\mathbf{x})},$$

which is exactly the log odds function. Thus the sign of an estimated *F*(**x**) can be used to classify sample **x** as 1 or −1. Since genes within the same pathway likely have much stronger interactions than genes in different pathways, in our pathway-based model setting, we assume additive effects across pathways and focus on capturing gene interactions within pathways:

$$F(\mathbf{x}) = \sum\_{m=1}^{M} H\_m(\mathbf{x}^{(m)}),$$

where each *Hm* is a nonlinear function that only depends on the expression levels of genes in the *m*th pathway and summarizes its contribution to the log odds function. Due to the additive nature of this model, it only captures gene interactions within each pathway but not across pathways.

Two existing methods, NPR [11] and GAR [12], employed the Gradient Descent Boosting (GDB) framework [18] to estimate the functional form of *F*(**x**) nonparametrically. GDB can be considered

as a functional gradient descent algorithm to minimize the empirical loss function, where in each descent iteration, an increment function that best aligns with the negative gradient of the loss function (evaluated at each sample point) is selected from a space of base learners and then added to the target function *F*(**x**). NPR and GAR extended GDB to be pathway-based by applying the descent step to each pathway separately and selecting the base learner from the pathway that provides the best fit to the negative gradient.

NPR and GAR differ in how they construct base learners from each pathway: NPR uses regression trees and GAR uses linear models. Due to the linearity assumption of GAR, it lacks the ability to capture complex interactions among genes in the same pathway. Using regression tree as base learners enables NPR to model interactions, however, there is no regularization in the gradient descent step, which can lead to selection bias that prefers larger pathways.

Motivated by NPR and GAR, we propose the PKB model, where we employ kernel functions as base learners, optimize loss function with second order approximation [19] which gives Newton-like descent speed and also incorporates regularization in selection of pathways in each boosting iteration.

## *2.1. PKB Model*

Kernel methods have been applied to a variety of statistical problems, including classification [20], regression [21], dimension reduction [22] and others. Results from theories of Reproducing Kernel Hilbert Space [23] have shown that kernel functions can capture complex interactions among features. For pathway *m*, we construct a kernel-based function space as the space for base learners

$$\mathcal{G}\_m = \{ g(\mathbf{x}) = \sum\_{i=1}^N K\_m(\mathbf{x}\_i^{(m)}, \mathbf{x}^{(m)}) \beta\_i + c : \beta\_1, \beta\_2, \dots, \beta\_N, c \in \mathbb{R} \},$$

where *Km*(·, ·) is a kernel function that defines similarity between two samples only using genes in the *m*th pathway. The overall base learner space is the union of the spaces constructed from each pathway alone: G = ∪*M m*=1G*m*.

Estimation of the target function *F*(**x**) is obtained through iterative minimization of the empirical loss function evaluated at the observed data. The empirical loss is defined as

$$L(\mathbf{y}, \mathbf{F}) = \frac{1}{N} \sum\_{i=1}^{N} I(y\_{i\prime}, F(\mathbf{x}\_i))\_{\prime \prime}$$

where **F** = (*F*(**x**1), *F*(**x**2), ... , *F*(**x***N*)). In the rest of this article, we will use the bold font of a function to represent the vector of the function evaluated at the observed **x***i*'s. Assume that at iteration *t*, the estimated target function is *Ft*(**x**). In the next iteration, we aim to find the best increment function *f* ∈ G and add it to *Ft*(**x**). Expanding the empirical loss at **F***t* to the second order, we can get the following approximation

$$L\_{\text{approx}}(\mathbf{y}, \mathbf{F}\_{\mathbf{f}} + \mathbf{f}) = L(\mathbf{y}, \mathbf{F}\_{\mathbf{f}}) + \frac{1}{N} \sum\_{i=1}^{N} [l\_{t,i} f(\mathbf{x}\_{i}) + \frac{1}{2} q\_{t,i} f(\mathbf{x}\_{i})^{2}],\tag{1}$$

where

$$\begin{array}{rcl}h\_{t,i} &=& \frac{\partial L(\mathbf{y}, \mathbf{F}\_{t})}{\partial F\_{t}(\mathbf{x}\_{i})} = -\frac{\mathcal{Y}\_{i}}{1 + e^{y\_{i}F\_{t}(\mathbf{x}\_{i})}},\\ q\_{t,i} &=& \frac{\partial^{2}L(\mathbf{y}, \mathbf{F}\_{t})}{\partial F\_{t}(\mathbf{x}\_{i})^{2}} = \frac{e^{y\_{i}F\_{t}(\mathbf{x}\_{i})}}{(1 + e^{y\_{i}F\_{t}(\mathbf{x}\_{i})})^{2}}\end{array}$$

are the first order and second order derivatives with respect to each *Ft*(**x***i*), respectively. We propose a regularized loss function that incorporates both the approximated loss and a penalty on the complexity of *f* :

$$L\_R(\mathbf{f}) = \begin{array}{c} L\_{\text{approx}}(\mathbf{y}, \mathbf{F}\_t + \mathbf{f}) + \Omega(f) \end{array} \tag{2}$$

$$=\frac{1}{N}\sum\_{i=1}^{N}\frac{q\_{i,t}}{2}(\frac{h\_{i,t}}{q\_{i,t}}+f(\mathbf{x}\_{i}))^2+\Omega(f)+\mathbb{C}(\mathbf{y},\mathbf{F}\_{l}),\tag{3}$$

where Ω(·) is the penalty function. Since *f* ∈ G is a linear combination of kernel functions calculated from a specific pathway, the norm of the combination coefficients can be used to define Ω(·). We consider both *L*1 and *L*2 norm penalties and solutions regarding each penalty option are presented in Sections 2.1.1 and 2.1.2, respectively. *C*(**y**, **F***t*) is a constant term with respect to *f* . Therefore, we only use the first two terms of Equation (3) as the working loss function in our algorithms. We will also drop *C*(**y**, **F***t*) in the expression of *LR*(**f**) in the following sections for brevity. Such a penalized boosting step has been employed in several methods (e.g., Johnson and Zhang [24]). Intuitively, the regularized loss function would prefer simple solutions that also fit the observed data well, which usually leads to better generalization capability to unseen data.

We then optimize the regularized loss for the best increment direction

$$
\hat{f} = \arg\min\_{f \in \mathcal{G}} L\_R(\mathbf{f}).
$$

Given the direction, we find the deepest descent step length by minimizing over the original loss function

$$\hat{d} = \arg\min\_{d \in \mathbb{R}^+} L(\mathbf{y}\_\prime \mathbf{F}\_t + \hat{d}\hat{f})\_\prime$$

and update the target function to *Ft*+1(**x**) = *Ft*(**x**) + *ν* ˆ*d* ˆ *f* , where *ν* is a learning rate parameter. The above fitting procedure is repeated until a certain pre-specified number of iterations is reached. The complete procedure of the PKB algorithm is shown in Table 1.

**Table 1.** An overview of the Pathway-based Kernel Boosting (PKB) algorithm.

1. Initialize target function as an optimal constant:

$$F\_0(\mathbf{x}) = \arg\min\_{r \in \mathbb{R}} \frac{1}{n} \sum\_{\ell=1}^N I(y\_{\ell\prime}r)$$

For t from 0 to T-1 (maximum number of iterations) do:

2. calculate the first and second derivatives:

$$h\_{t,l} = -\frac{y\_l}{1 + e^{y\_l F\_l(\mathbf{x}\_l)}}, \eta\_{t,l} = \frac{e^{y\_l F\_l(\mathbf{x}\_l)}}{(1 + e^{y\_l F\_l(\mathbf{x}\_l)})^2}$$

3. optimize the regularized loss function in the base learner space:

$$f = \arg\min\_{f \in \mathcal{G}} L\_R(\mathbf{f}),$$

4. find the step length with the steepest descent:

$$\hat{d} = \arg\min\_{d \in \mathbb{R}^+} L(\mathbf{y}, \mathbf{F}\_l + d\hat{f})$$

5. update the target function:

$$F\_{l+1}(\mathbf{x}) = F\_l(\mathbf{x}) + \nu df(\mathbf{x})$$

End For return *FT*(**x**)


4. Results and discussion

### 4.1. Char characterization

The char yield, oil yield, and gas yield from the pyrolysis process are 31.6, 16.0 and 52.4%, respectively. The char yield is satisfying and encouraging in terms of the potential commercial opportunity for coconut shell to be used as a feedstock to produce a substitute carbon black. The oil yield and gas yield are both beneficial so that further implications of these two byproducts have great potential.

Table 4 summarizes the transmittance of toluene extract (T%), pH value, BET surface area, Tplot surface area, and acidic groups and basic groups on the surface of both commercial carbon black N772 and the pyrolytic coconut char filler.

Toluene transmittance correlates to the amount of tarry or leachable contents in the carbon black as the leachable and unburned tarry or oil-residues on the surface of carbon black or the char can be dissolved into it. This is very important for potential applications, since the presence of a high leachable (oily) content may cause contamination during processing into rubber or other applications and present problems in the appearance and performance of the final rubber products. According to Table 4, the toluene transmittance of char fill is 99.95; it

Table 4. Characterization of char filler and carbon black N772.

shows that the filler is quite clean and pure with little surface contamination. However, the carbon black N772 only has 65.9% of the T%, which indicates that a significant amount of leachable components exists indicating a limiting effect on the purposes.

It is widely known that pores on the surface of solids are classified into three size ranges: micropores (<2 nm width), mesopores (<2–<50 nm with), and macropores (>50 nm width). Normally, if the pores (micropores and small mesopores) are significantly smaller than the very large rubber polymer chains, then the polymer molecules cannot access to these pores. Therefore, unlike micropores present in activated carbon, meso- and macropores may play the decisive role on the filler surface. From Table 4, the area of all pores on N772 is 28.5 m2 /g and the area of meso- and macropores is 26.6 m2 /g. The results indicate that meso- and macropores occupied most of the surface area of carbon black, which reaffirms previous statements about the importance of these pores in carbon black's application in the rubber industry. The BET surface area of the char filler is 373.31 m2 /g, whereas the t-plot surface area is 315.86 m2 /g, which follows the same trend with N772. Moreover, the surface areas are much greater than N772. These data further support the assertion that char samples can be used as an alternative rubber filler.

The pH value of the char surface has been recognized as a foundation of the reinforcing ability of the fillers. It is reported that basic materials may accelerate vulcanization reactions, while acidic ones may delay the vulcanization time of a rubber compound [17, 48]. According to the above, a solution pH value close to 9 makes N772 suitable filler for a wide range of application with reasonable vulcanization time and ideal amount of free radicals. The pH value of the char sample was close to 9, which also supports the proposition that coconut shell could be a promising feedstock for rubber fillers. The surface chemical groups on the surface of char filler are much more plentiful than the carbon black N772, which makes char surface more active resulting in a better interaction and reinforcement from coconut shell char.

#### 4.2. In-rubber characterization

formulation is shown in Table 3, which was applied in the compounding process to investigate the performance of the char filler in rubber. Compounds were produced using a 60 cc

Ingredient Parts per hundred of rubber

SBR 1502 100 Char filler 60 TDAE oil 10 Zinc oxide 5 Stearic acid 2 6PPD 1.5 TBBS 1.5 Sulfur 1.5

The moving die rheometer (MDR) test was conducted based on ASTM D5289, at 160C for 30 min. The results of the MDR were used to evaluate the cure characteristics of each compound and to allow preparation of cured sheet using a cure time of T90 + 5 min. Shore A hardness was tested according ASTM D2240. Tensile properties were determined following ASTM D412. A scanning electron microscopy (SEM) (Auriga Cross Beam, Zeiss) was applied to analyze the surface morphology of the char filler-filled rubber sample and to understand the

The char yield, oil yield, and gas yield from the pyrolysis process are 31.6, 16.0 and 52.4%, respectively. The char yield is satisfying and encouraging in terms of the potential commercial opportunity for coconut shell to be used as a feedstock to produce a substitute carbon black. The oil yield and gas yield are both beneficial so that further implications of these two by-

Table 4 summarizes the transmittance of toluene extract (T%), pH value, BET surface area, Tplot surface area, and acidic groups and basic groups on the surface of both commercial carbon

Toluene transmittance correlates to the amount of tarry or leachable contents in the carbon black as the leachable and unburned tarry or oil-residues on the surface of carbon black or the char can be dissolved into it. This is very important for potential applications, since the presence of a high leachable (oily) content may cause contamination during processing into rubber or other applications and present problems in the appearance and performance of the final rubber products. According to Table 4, the toluene transmittance of char fill is 99.95; it

Brabender mixer set at 40C and 60 rpm.

Table 3. SBR formulation [9, 11].

96 Advanced Surface Engineering Research

4. Results and discussion

4.1. Char characterization

products have great potential.

mechanism of the char filler with the rubber matrix.

black N772 and the pyrolytic coconut char filler.

The cure and physical properties of the rubber compounds filler with the two fillers assessed by the moving die rheometer (MDR) test are summarized in Table 5. At the beginning, a mixture is heated in the cavity of the rheometer under pressure. Then, the viscosity decreases

Table 5. Rheology and physical data of coconut shell char and N772.

and the torque exerted on the rotor drops. The lowest torque value is called moment lowest (ML), which can be used to study the stiffness of the uncured rubber compound at a given temperature, noted as "Min" in Table 5. After the curing process begins, the torque rises. When the torque increases 2 dNm unit above ML value, the time is recorded as Ts2. It tells about the moment the curing process actually starts. With the curing progressing, the torque

continues increasing. After some time, the torque reaches the maximum value and a plateau appears. The highest torque is regarded as moment highest (MH), also noted as "Max" in Table 5. The time from the beginning of the test to the point where 90% of the MH value attained is called T90. The hardness of the filled rubber compound is tested by the Shore A with degree unit according to the ASTM D2240 standard. The M100 and M300% are the stresses required to produce an elongation of 100 and 300% of the test sample. The maximum tensile stress recorded in extending the test piece to a breaking point is shown as tensile strength; and the elongation at break is the tensile strain in the test length at breaking point

The Potential of Pyrolytic Biomass as a Sustainable Biofiller for Styrene-Butadiene Rubber

http://dx.doi.org/10.5772/intechopen.79994

99

According to Table 5, the time to onset of cure (Ts2) and cure times (T90) of the coconut char filled SBR were comparable but slightly longer than conventional carbon black N772. Different surface chemistry may be the reason, since it may have some interactions with the cure package. The hardness value was slightly high than N772, also indicating that coconut shell has the potential to be used as the parent material of rubber filler. The M100% values are found to be higher than the commercial carbon black. The low tensile strength and high elongation to break values imply that there are low filler-polymer interactions and structure levels, allowing for chain slippage over the filler surface, which can be enhanced through modification of the rubber mix formulation [9]. Based on this data, the sample can be considered as a semi- to lowreinforcing filler with broadly similar cure characteristics to conventional carbon black.

The SEM plots of coconut char compounded rubber sheet and N660 (which behaves better in the rubber matrix than N772) filled rubber sheet at 25 K magnification are shown in Figure 4. According to the images that base layer is the rubber matrix, the small particles on the surface are fillers (char filler and N660). It can be seen from the images, the fillers are unevenly attached to the surface of the rubber, indicating that the mechanism of the interaction between char filler and rubber is similar to conventional carbon black. Particle shapes, sizes, and its distribution are the main differences between coconut char and commercial carbon black. Smaller aggregate size and more uniform size distribution of carbon black plus spheroid particles may be helpful during the vulcanization process leading to good rein-

Coconut shell, as a high-volume problematic waste material, has the potential to be successfully converted into a high-quality carbon black-like char filler, and high heat value, renewable energy materials (mainly oil and some gases) at relatively small scale. Thus, global fossil fuelderived emissions can be reduced by the help of the ability of biochar to sequester the carbon contained in the coconut shell by conversion into a stable and nonavailable form. This type of process has been regarded as popular sector with growth potential in the global carbon market

suitable surface pH (9.70), can be achieved by the coconut shell char filler. The char filler produced

/g), along with high levels of purity (99.95%) and

with a controllable, clean, and simple manufacturing process.

High external surface area values (315.89 m2

[11, 52].

forcement.

5. Conclusion

Figure 4. SEM plots of compounded rubber sheets at 25 K magnification, illustrating rubber-filler bonding system [11]. (a) SEM plot of Run 20 filled rubber sheet. (b) SEM plot of N660 filled rubber sheet.

continues increasing. After some time, the torque reaches the maximum value and a plateau appears. The highest torque is regarded as moment highest (MH), also noted as "Max" in Table 5. The time from the beginning of the test to the point where 90% of the MH value attained is called T90. The hardness of the filled rubber compound is tested by the Shore A with degree unit according to the ASTM D2240 standard. The M100 and M300% are the stresses required to produce an elongation of 100 and 300% of the test sample. The maximum tensile stress recorded in extending the test piece to a breaking point is shown as tensile strength; and the elongation at break is the tensile strain in the test length at breaking point [11, 52].

According to Table 5, the time to onset of cure (Ts2) and cure times (T90) of the coconut char filled SBR were comparable but slightly longer than conventional carbon black N772. Different surface chemistry may be the reason, since it may have some interactions with the cure package. The hardness value was slightly high than N772, also indicating that coconut shell has the potential to be used as the parent material of rubber filler. The M100% values are found to be higher than the commercial carbon black. The low tensile strength and high elongation to break values imply that there are low filler-polymer interactions and structure levels, allowing for chain slippage over the filler surface, which can be enhanced through modification of the rubber mix formulation [9]. Based on this data, the sample can be considered as a semi- to lowreinforcing filler with broadly similar cure characteristics to conventional carbon black.

The SEM plots of coconut char compounded rubber sheet and N660 (which behaves better in the rubber matrix than N772) filled rubber sheet at 25 K magnification are shown in Figure 4. According to the images that base layer is the rubber matrix, the small particles on the surface are fillers (char filler and N660). It can be seen from the images, the fillers are unevenly attached to the surface of the rubber, indicating that the mechanism of the interaction between char filler and rubber is similar to conventional carbon black. Particle shapes, sizes, and its distribution are the main differences between coconut char and commercial carbon black. Smaller aggregate size and more uniform size distribution of carbon black plus spheroid particles may be helpful during the vulcanization process leading to good reinforcement.


**CFD Modelling and Simulation of Water Turbines**

Editors

**Santiago Lain Omar Dario Lopez Mejia**

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**1. Introduction**

Over the last fifty years, exploration of the processes and orientation of informal education has been erratic. The topic was researched for a short time in English primary education post-Plowden and was glimpsed in UK youth work in the 'Albemarle period' but only much later returned [1–3]. We find a more consistent presence within adult and lifelong education via Brookfield [4] on adult learning in the community; Coombs [5] on non-formal education; Kolb's [6] return to Dewey via experiential learning; and Lave and Wenger's work on situated learning [7]. There has, however, been a strong and continuing tradition of addressing pedagogic processes and orientations within continental European social work and care—and education more broadly. While this area of exploration has had a marginal impact upon care and social work training in the UK [8–10], it has been largely ignored or misunderstood within 'Anglo-American' traditions of thinking and practice concerning education [11].

This paper looks briefly at these arenas of practice and highlights three fundamental problems. The tendency on the part of both academics and practitioners to:

The result overall is a profoundly misdirected professional education arena.

## **2. Informal Education**

Predictably, we cannot vouchsafe the date when the term 'informal education' first surfaced but can say it has tended to be used in two main ways. The first is to describe educational activities taking place in non-school settings. The second usage delineates two contrasting processes of, and orientations to, facilitating learning—one largely instructional and organized by a curriculum, the other emerging from experience, reflection, and conversation. As John Dewey [12] put it, 'In what we have termed informal education, subject matter is carried directly in the matrix of social intercourse. It is what the persons

**Citation:** Jeffs, T.; Smith, M.K. The Education of Informal Educators. *Educ. Sci.* **2021**, *11*, 488. https:// doi.org/10.3390/educsci11090488

Academic Editors: Mike Joy, Pam Alldred and Frances Howard

Received: 15 June 2021 Accepted: 18 August 2021 Published: 1 September 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

with whom an individual associates do and say'. The challenge for Dewey was how best to balance informal and formal education, and incidental and intentional learning.

Within Anglo-American practice the development of thinking about how to prepare practitioners as informal educators has largely centred around the work of three groups of people. The first was a formidable set of academics following in John Dewey's footsteps and based in the American YMCA and YWCA in the 1920s and 1930s. The second was a similarly impressive group of women working in the UK at the National Association of Girls and Mixed Clubs during the 1940s. The earliest full-length treatment of informal education [13] grew out of their activities. The last group was based at, or connected with, the YMCA George Williams College in London. They drew on the work of the other two groups, added in contemporary contributions, and then developed, and ran the only dedicated professional development degree programmes in informal education in the world. Wrapped up with these were also developments in primary schooling, community education and specialist education.

### *2.1. Chicago and Group Work*

We can see a focus on setting in the pioneering activities of staff teaching at George Williams College (Chicago) in the mid-1920s. Informal education or what was more often dubbed "recreational and informal education" emerged as a portmanteau term utilised to identify the educational work undertaken by settlement houses, youth-serving organisations (such as the YMCA, YWCA, uniformed groups, and the boys' and girls' clubs), neighbourhood centres, and adult education programmes. Interestingly, professional preparation programmes such as those based at George Williams College (Chicago) 'were grounded primarily in the educational philosophy of John Dewey' [14] but this had not fully found its way into the conceptualisation of informal education in use there.

*George Williams College* staff during the inter-war years were anxious to extend their portfolio of degree programmes and to offer courses that would equip individuals to work in the recreational and informal education sectors. However, rather than launch an informal education degree programme with specialist routes it opted to develop programmes linked to what they termed "social group work". Most of the key figures in the development of social group work either taught at the college—Hedley Dimock, Charles E. Hendry and Harleigh B. Trecker; or worked closely with it—Gertrude Wilson and Gladys Ryland (Chicago YWCA), Neva Boyd (Hull House Settlement, Chicago) and the doyen of group work theorists Grace Coyle who was employed by the YMCA for most of the 1920s and 1930s. Their reasoning for doing so was that:

*Informal education leaders entered their fields with the assumption that small group face-to-face encounters provided the best context within which people, including children, could solve their common problems or set new goals. A well-functioning small group was seen as a powerful agency for change. Consequently, under the guidance of a skilled guide, these groups and their members were fully equipped to establish and pursue appropriate goals and/or solve problems encountered in their paths. With help, young people in particular, could be led to discover, intelligently respond to and better manage the challenges and opportunities they faced*. [14]

The decision clearly reflected a desire to equip graduates with a skill set that would enable them to survive in highly demanding settings. This was a period when youth serving organisations often found themselves catering for numbers that are not currently encountered. Chicago YMCA in the 1930s had a membership of 32,000 and operated from a thirteen-storey headquarters plus five large outreach centres. The boys' club run by Hull House Settlement nearby to the College—and a venue where students undertook placements — had a membership of 1500 [15]. Social group work was viewed as a method that would enable a restricted number of professional workers to operate with large numbers to create educational opportunities and foster relationships. Besides the Chicago group, there were others working for the YMCA involved in developing thinking around informal and lifelong education in the States. Notably, these included two writers heavily influenced by Dewey—Eduard Lindeman [16] who briefly taught at George Williams College between 1918 and 1919 and Ruth Kotinsky [17] who worked for the National YMCA in the 1920s and 1930s [18]. Later they were followed by Malcolm Knowles who is now known for his work on andragogy but who also wrote *Informal Adult Education* [19].

### *2.2. The National Association of Girls and Mixed Clubs*

The first book-length exploration of informal education appeared in 1946. Written by Josephine Macalister Brew, it argued that education should be taken 'to the places where people already congregate, to the public house, the licensed club, the dance hall, the library, the places where people feel at home' [13]. She explored how educators can 'insert' education into such units. In particular, she focused on what we might describe now as the process of creating and exploiting teaching moments. In an earlier book, she had started to explore how to do this:

*Only by the slow and tactful method of inserting yourself unassumingly into the life of the club, not by talking to your club members, but by hanging about and learning from their conversation and occasionally, very occasionally, giving it that twist which leads it to your goal, is it possible to open up a new avenue of thought to them*. [20]

Brew was a member of a talented team of women who during their time with NAGC&MC and after they departed were prolific authors and influential practitioners. These included Eileen Younghusband (who was later to write several seminal books and reports in social work); Madeline Rooff, Lesley Sewell, Desiree Edwards-Rees and Pearl Jephcott — a gifted social researcher, worker, and organizer [21,22]. One of the significant features of this group is that while they were focused on work with young people, they had also been active in a range of settings including educational settlements, school, and university teaching, social research, social settlements, and social work, as well as youth work.

### *2.3. YMCA George Williams College*

The only extant undergraduate or postgraduate degree programmes in 'informal education' appeared some sixty years after the Chicago pioneers. Developed by the *YMCA George Williams College* (London), these ran from 1992 to 2015 [23]. The programmes led to professional qualifications for both UK youth work and Community Learning and Development (CLD) (Scotland). From 2012 onwards the College developed a focus on pedagogy offering degrees, for example, in social pedagogy and in work with children, young people and families. YMCA George Williams College effectively closed in 2021 [23].

The College had been established in 1970 to train youth workers and developed a distinctive approach. In significant part this was shaped by M. Joan Tash, the senior tutor. At the core of the *modus operandi* lay an emphasis on the development of the whole person and the connectedness of human life. At one level this should not be surprising given the YMCA triangle of body, mind, and spirit, and the Humanics orientation of the first YMCA College opened in Springfield Massachusetts in 1885. Humanics being the term first employed to describe the broad syllabus developed by the College to train YMCA Secretaries via the study of human nature, relationships, and affairs [24,25]. Tash embraced a focus on process, reflection, individual supervision, and groupwork. Josephine Klein adopted a similar mix in the new Goldsmith's College training programme launched in 1965. However, there were also differences linked to their contrasting professional backgrounds (Klein's in sociological research and psychotherapy; Tash's in the YWCA, non-managerial supervision, and fieldwork research).

As a 'monotechnic' institution the College was unhampered by the 'research assessment' procedures that have blighted UK universities since the late 1980s. College tutors were free to focus on writing and commissioning material associated with the very worlds of practice their students engaged with [23]. Hence informal education became a focus for exploration and rethinking of the role, functioning and processes of education outside curriculum focused practice [3,26]; the nature of accompanying and helping was explored and debated [27–29]; the character of grassroots practice examined [30]; and the state of

faith-based youth work investigated [31]. As was the case with the NAGMC group, staff were drawn from a wide range of academic and practice traditions but were operating within a framework created by membership of an international movement, and by links to a wide range of local, community-based organisations across the UK. In part, this arose from the College's work with the Rank Foundation, which between 1988 and 2017 funded an extensive array of long-term developmental projects.

The College had recognized that a return to John Dewey and others' concern with community, process and orientation was needed. Furthermore, there was an appreciation that delineation between informal and formal education could be traced back to ancient Greece and the different approaches and concerns linked to diadacts and pedagogues. The former were basically instructors (*didáskalos*) and their task was to teach their subject. Pedagogues (*paidag*ö*gus*) had two common roles. One was to be an accompanist or companion; the other, and more fundamental, task was to help their charges learn what it was to act well. This they did by a combination of, for example, conversation and disciplining. Greek pedagogues were, in short, moral guides [11]. Unfortunately, in recent Anglo-American usage, teaching and pedagogy became simplistically confused. The latter is commonly defined as the art and science of teaching [32] and the full contemporary meaning of pedagogy has thus been obscured.

### **3. Youth Work**

Little effort was made in the youth work sector in the UK over the forty years following Brew's [13] work to locate and build upon informal education's theoretical roots or to explore what being an 'informal educator' might mean in practice. Post-war austerity significantly reduced funding for the work, and in the 1950s, programmes like the Duke of Edinburgh's Award Scheme attracted attention (Brew herself was one of the main contributors to the design of the scheme). Additionally, developments in US group work garnered interest—and US-based writers were joined by UK-based practitioners and researchers such as Josephine Klein [33,34]. Their work was marked by an ability to draw on contemporary research, engage in a sustained way with practice, and to connect with developments in social psychology and psychoanalysis.

With a growing moral panic around the behaviour of young people, the English government set up the enquiry that resulted in *The Albemarle Report* [35]. Significant expenditure upon training, employing a cadre of full-time workers, and building new youth centres followed. The Youth Service was seen as having two central functions: (a) the socialisation and social education of the mass of young people a majority of whom at the time of publication entered the workforce at age 15; and (b) the control and containment of a deviant minority. While there was talk of informal and social education, the terms were not defined or the relationship between them discussed in the report. Influential works by Goetschius and Tash [36] and Davis and Gibson [37] were to explore the nature of the later as a way of expressing process and purpose, but after the 1960s it too was rarely subjected to serious enquiry [1,38].

Another long period of austerity, combined with the extension of schooling, and changing leisure habits and social attitudes, had brought about a substantial reduction in the number of young people involved in youth work from the late 1970s—especially amongst those aged 15 and above. Structural problems arising from deindustrialization, financialization, and growing deprivation and poverty were also taking their toll. 'Youth' was therefore no longer a consistently helpful organizing idea for intervention [39]. Yet, little effort was made to rethink training and practice and to address the elephant in room. Youth services had been established to offer leisure and educational opportunities to those over the school leaving age of 14 and up to 18 years who were in full-time employment. Most of this age range were now remaining (or in many instances trapped) in full-time education and displayed no sustained interest in youth service provision. Thus, the longterm decline in state-sponsored youth services was unlikely to be reversed, resulting in

it withering away [1,39]. However, there remained a possibility that provision linked to religious and civil society groups may survive and even flourish [40,41].

#### **4. Schools, and Informal Education**

Within English primary education following the Plowden Report there was a brief flowering of practice that looked back to Dewey's concerns with experience, reflection, and exploration. Chapter Two of the report famously opened 'At the heart of the educational process lies the child' [42]. Such 'child-centred' education was often talked about as involving schools moving away from 'acting upon' students, to becoming places 'for growing and developing' [43].

The result was a growing focus on activity or discovery methods, and the use of group work—for example drawing on the work of Leslie Button [44] to develop active tutorial work, and later attempts to reform the primary school classroom [45]. We also saw the development of 'open' classrooms and schools [46,47]. Thereby, 'informal education' was gifted a recognised presence within many schools, particularly those with larger classrooms that allowed students to work collaboratively in groups with interventions from a team of teachers. 'Open' was often used in a rather literal sense—that of physical space — rather than as an orientation or being open to new ideas and experiences. Key writers like Lillian Weber explicitly drew on Dewey and his forerunners and their work was informed by contemporary social psychologists and educationalists like Susan Issacs, Jerome Bruner, and Basil Bernstein. Weber, for example, attended to setting, relationships and processes in her discussion of informal education:

*Informal, as I understand it, refers to the setting, the arrangements, the teacher-child and child-child relationships that maintain, restimulate if necessary, and extend what is considered to be the most intense form of learning, the already existing child's way of learning through play and through the experiences he seeks out for himself*. [48]

There was a major backlash against these developments in schools in both the USA and the UK [49]. In part, this was based on the growing political influence of product-oriented approaches fixated with the acquisition and testing of a narrowly defined band of core knowledge; and a focus on skilling. However, we can also see that many teachers and school administrators struggled with the sophistication and stance of informal educational practice—and the extent to which it put the control of learning into the hands of the learners. It entailed having to embrace and balance both a didactic and a pedagogic frame of reference. It involved cultivating an educational imagination.

In some places this orientation was linked to, or found an expression in, the development of community schools in England—notably in the Cambridgeshire village colleges and subsequently in Coventry and Leicestershire [50]. These initiatives both opened schools to local communities including enabling adults to learn languages etc. alongside young people, as well as providing facilities for the use of local groups. They also often included substantial youth work and adult education programmes located within the school [51]. With the rise of the national curriculum, a narrowing of focus, substantial cutbacks in funding and the transfer of schools from local authorities to trusts, informal education of this kind largely faded from view—although there are some examples remaining from later Scottish initiatives—particularly in rural and island communities.

### **5. Adult Learning, Community Organization and Community Education**

Within many countries there had been a long tradition of what might be called community adult education. This had existed alongside autonomous adult learning and discussion groups, and opportunities for learning within community action and community development initiatives. The latter had become more visible in England at the same time as the exploration of informal education was at its height in primary schooling [52]. Influential examples of UK practice could be found in the work of Eric Midwinter with the Liverpool Education Priority Area [53,54] and his establishment of the University of the Third Age in 1973; and Tom Lovett's work on adult education and community action [55–57] and

in the establishment of Ulster People's College. In Scotland, we see the emergence of 'community education' as a way of thinking about, and integrating, the activities of youth workers, community organizers and adult educators—especially after the publication of *The Alexander Report* in 1975 [58].

Looking further afield—and emerging out of the need to examine the work of nongovernmental organisations like the YMCA and YWCA in development programmes —there was 'refinement' of the definition of education by a setting or organizing agent. Within bodies such as UNICEF it was being argued that formal educational systems had failed to adapt to the socio-economic changes around them [59]. The result was an influential classification that placed non-formal alongside formal and informal education.

*Formal education: the hierarchically structured, chronologically graded 'education system', running from primary school through the university and including, in addition to general academic studies, a variety of specialized programmes and institutions for full-time technical and professional training*.

*Informal education: the truly lifelong process whereby every individual acquires attitudes, values, skills and knowledge from daily experience and the educative influences and resources in his or her environment—from family and neighbours, from work and play, from the marketplace, the library and the mass media*.

*Non-formal education: any organized educational activity outside the established formal system—whether operating separately or as an important feature of some broader and learning objectives*. [5]

It provided a neat categorization for administrators and was attractive to some practitioners and academics perhaps because it appeared to chime with Illich's [60] argument for deschooling and Freire's [61] work on literacy, dialogue, and praxis. However, this categorization activity was deeply problematic pedagogically, especially in the way it mixed institutional settings with processes, and schooling with education [62]. Identical processes, for example, could be found in each of the categories. The same group discussion of ethics, for example, could be conducted in a university seminar room, a community centre, or around a table in a bar. It was in this context that Brookfield [4] undertook a seminal exploration of adult learning in the community which looked at deliberate processes aimed at learning that did not have closely specified goals. This took us neatly back to Dewey, and to using conversation as a major organizing idea for informal education and curriculum for formal.

### **6. Stuck in Silos, and Lacking an Educational Imagination**

It was obvious to those who looked that practitioners in quite different sectors residential work, schooling, probation, community development, youth work, lifelong learning, and religious organisations—were engaged in informal education [2]. Most shared, even if they were unfamiliar with his writings, Dewey's concern with the enlargement and emancipation of experience, and with building a life in common; drew upon similar roots in liberal education; and placed a value on conversation and reflection. However, they were working in arenas of practice that often lacked the tools or understandings to recognize the worth of what they were trying to do.

One of the abiding features of contemporary organisations and fields of practice is the extent to which their members thoughts and actions are fragmented and ensnared. They are also commonly trapped in occupational silos as a consequence of professional training and cultures that place an emphasis on the supposed uniqueness of their mode of intervention. In this setting it is easy to ignore the commonalities of practice and shared realities that link crafts and professions. One key quality, as Richard Sennett [63] has pointed out, is an aspiration for quality. Another, according to Peter Korn is a concern with creativity, bringing 'something new and meaningful into the world' [64]. Silos result, all too often, in tunnel vision, failure to recognize risk and change, and inability to innovate [65]. As Daniel Kahneman [66] put it, 'We can be blind to the obvious, and we are also blind to our blindness'.

We can see this process at work in Scotland in the attempts to integrate adult education, community development and youth work following the Alexander Report [61] First, each of the groupings had fairly negative views of each other and different orientations. Adult education was organized around classes and teaching and had a largely middle-class clientele; community development workers focused on groups in deprived communities and were concerned with animation, advocacy and policy change; and youth workers tended to be based in clubs in working class areas and focused on the provision of activities [67]. There were constant complaints from each of the three arenas that the interests of their 'clients' were not being addressed. Second, it took some time for government agencies to define what they meant by 'community education' [68] and there was no coherent policy for integration, certainly not one that addressed 'the human relations issues arising out of ... interservice and inter-institutional rivalries' [69]. Third, Scotland, like many other countries, has experienced short phases of development followed by cuts and long periods of austerity often driven by decisions made in Westminster. Participative and reflective approaches to learning have been discarded under a strong central government emphasis upon schooling, skilling and datafication [70].

While there have been developments in the way we can understand and embrace informal education, they have not gained much traction either in the field or the academy. Too many have been unable to escape or even recognize the silos they are in. There were elements of this in the Scottish experience of community education even as the thinking about practice morphed into community learning and development. Practitioners and academics in the area had to deal with a strong, and ill-informed, emphasis on measurement and outcomes, and with an increasingly centralized state. That said, the framework developed in Scotland for professional education in community learning and development was more coherent and more appropriate to the needs of informal educators than that south of the border in youth work and community development [71]. It was, for example, used to shape the degree programmes in informal education already discussed at the YMCA George Williams College.

For all the talk of 'education' within the sectors that are our concern here there is a fundamental problem at their core, they lack an 'educational imagination'. Within Anglo-American traditions there is a strong tendency to confuse education with schooling, and as we have already seen, teaching with pedagogy. Much schooling and teaching cannot be accurately described as 'education', neither can a great deal of youth work and community development work [72]. Many practitioners and academics lack a particular 'quality of mind' that enables them to frame 'what is going on in the world and of what may be happening within themselves' [73]. This is not just a case of thinking like an educator, but also of being one. It entails accepting that teaching and pedagogy, in each and every setting—formal and informal—is a calling, a vocation. It matters not if they occur via the medium of conversation, dialogue, role-modelling, or a PowerPoint, nor that it might take place in a community group, club, out on the street, in a corridor, classroom or wherever; the how and where are unimportant if the practitioner accepts that it is in essence a calling and a craft. In an inspirational passage, worth quoting at length, George Steiner encapsulates much of this reality in relation to teaching.

*To teach seriously is to lay hands on what is most vital in a human being. It is to seek access to the quick and the innermost of a child's or an adult's integrity* ... *Poor teaching, pedagogic routine, a style of instruction which is, consciously or not, cynical in its merely utilitarian aims, are ruinous. They tear up hope by its roots. Bad teaching is, almost literally murderous and, metaphorically, a sin. It diminishes the student, it reduces to gray inanity the subject being presented. It drips into the child's or the adult's sensibility that most corrosive of acids, boredom, the marsh gas of ennui. Millions have had mathematics, poetry, logical thinking killed for them by dead teaching, by the perhaps subconsciously vengeful mediocrity of frustrated pedagogues* ... *. In actual fact, as we* *know, the majority of those to whom we entrust our children in secondary education, to whom we look for guidance and example in the academy, are more or less amiable gravediggers. They labour to diminish their students to their own level of indifferent fatigue. They do not "open Delphi" but close it*. [74]

This absence of educational imagination is not limited to the formal sectors of education but is also a feature of professional training courses through much of the informal sector. What, then, does the educational imagination involve?

First, as can be seen in Figure 1, it entails what Joe Sachs [75] talks about as an 'active condition' and what Aristotle discusses as *hexis*: a readiness to sense and know. It also entails a calling to act. Second, it requires a guiding *eidos* or leading idea. John Dewey [12] classically talked about educators engaging with people 'to enable them to share in a common life' and, in Aristotle's terms, to flourish. Third, there is a disposition, what in German traditions of social pedagogy is described as *haltung* or stance [76]. Pedagogues are called to act in the belief that, as Bertold Brecht put it some time ago, 'when taking up a proper bearing, truth ... will manifest itself." [77]. Here we can describe this as a concern and a calling to act respectfully, knowledgeably, and wisely. A focus on dialogue and learning, and action that is informed and committed flows from this orientation [78].

**Figure 1.** The educational imagination.

### **7. Little Grounding in Social Sciences and Moral Philosophy**

Once we recognise that at the core of education is a stance or *haltung* that requires practitioners to act respectfully, knowledgeably, and wisely, it becomes clear why a solid grounding in the social sciences or what Barrow [79] refers to as the foundational disciplines, psychology, sociology, history, and philosophy, are essential for all those involved in

education, in any setting. Without these and a moral philosophy we cannot respond to situations appropriately. We will lack the means to make sound judgements. This understanding was central to the activities of the Chicago pioneers of training for informal education and social groupwork in the 1930s. Sadly, it has been lost (or never found) in many professional programmes. A growing emphasis on skills, delivery, set procedures, and the measurement of predetermined outcomes tends to substitute often ill-informed technical objectives for dialogue and the emergence of wisdom.

'Good teaching', Parker J Palmer [80] argued, 'cannot be reduced to technique; good teaching comes from the identity and integrity of the teacher'. The same can be said of helping relationships generally [29] and for informal educators and pedagogues specifically. The Social Pedagogy Professional Association, for example, expects a particular philosophy and *haltung* to be 'held in a [pedagogue's] heart and guide their way of living and working' [81]. Palmer talks about good teachers (and here we can add pedagogues) possessing a capacity for connectedness.

*They are able to weave a complex web of connections among themselves, their subjects, and their students so that students can learn to weave a world for themselves* ... *The connections made by good teachers are held not in their methods but in their hearts meaning heart in its ancient sense, as the place where intellect and emotion and spirit and will converge in the human self*. [80]

These ways of talking about teachers and pedagogues do not sit well with the current orthodoxies within schooling, social work, community learning and development, and youth work. Within professional training for these areas, inadequate attention has been given to the 'who' or selfhood of the practitioner, and their interconnectedness with others and the world around them. Wrapped up with this, scant consideration has been given to deepening and extending practitioner's appreciation of moral philosophy, social psychology, social anthropology, social policy, economics, and the historical origins of contemporary practice. The overall result is that practitioners struggle to form an identity and frame of reference as educators and pedagogues (and get stuck in silos); lack the knowledge and disposition to make informed judgements and formulate useful theory; and are more likely to fall in line with policies and procedures that disadvantage the individuals and communities they are working with. As Quintilian, writing in the first century A.D., warned:

*Let no one however demand from me a rigid code of rules such as most authors of textbooks have laid down* ... *Most rules are liable to be altered by the nature of the case, circumstances of time and place, and by hard necessity itself* ... *Rules are rarely of such a kind that their validity cannot be shaken and overthrown in some particular or other*. [82]

Quite aside from a fundamental misunderstanding of the nature of education and pedagogy, there are also forces within higher education institutions that have contributed to the failure to ground student practitioners in the basics and develop professional identity. These include a growing tendency to view course participants as customers rather than students; the use of modular degree programmes where 'customers' can mix and match courses according to their own tastes rather than what they need in order to be professional and meet the needs of those they work alongside—clients and colleagues alike; and a valuing within universities of the publication of 'research' over engagement with practice and the individuals, contexts and agencies doing so involves. In short, they have been unable to create an environment where students can grow and create together the knowledge, wisdom, and ability to connect and engage with people that are necessary for teaching and pedagogy.

### **8. Problems of Content**

Linked to the above there flows a further failure in training for informal education. Programmes have not generally addressed the issue of what exactly those qualifying are

competent to 'educate' others in. Informal educators look to experiences, conversations and 'teachable moments', they also engage in formal programmes of teaching. Formal and informal education are not separate entities, 'they are rather a continuum shading gradually into one another' [83]. All alike are involved in an improvisational endeavour. One that requires practitioners to possess an arsenal of knowledge or what Lucy Shuker and Naomi Thompson [84] dub 'literacies', which they can communicate to others in a logical and lucid manner. Therefore, they must be fluid, nimble and flexible to adapt to the ebbs and flows of conversation and dialogue, and the variability of the world around them. We therefore must ask, what are they equipped to 'teach'? There are two main things to consider here: the subject knowledge and understanding that flows from a grounding in the social sciences and moral philosophy, and the specialist knowledge and skills in particular areas. We will look at the latter first.

We will seek to illustrate this by considering in part the work of the many informal educators working outdoor education. It entails them running training and coaching programmes and being qualified in the activities they are facilitating and teaching. They must maintain and extend their skill levels, be up to date on developments in their specialisms and be regularly re-accredited. National standards and structures are in place to facilitate this. In this respect they are no different from the 'coaches' and 'instructors' they work in tandem with. In one setting, for example, all three must be competent to teach novices how to safely mount a horse, sit in the saddle and walk it out. However, educationalists, outdoor educators and informal educators must be equipped to do much more than instruct novices in the rudiments of riding.

For a start, they must be able to draw upon a well of experience, information and theory that allows them to explain this 'skill' and contextualise and locate it within a conceptual framework. Possessing that framework means when the opportunity arises, they can, for example, exploit it to reflect upon equine physiology, the history of the different breeds, the design and manufacture of saddles or animal psychology. Equally, the conversation accompanying the task and experience might be nurtured by the educator so as to enable the group to reflect upon the moral and ethical issues relating to the 'exploitation' of horses for human enjoyment by drawing on the ideas of writers and philosophers such as Peter Singer [85] or Erica Fudge [86]; or alternatively to a consideration of the aesthetics of horse-riding, or reflection on the rich array of art linked to the horse for instance the paintings of George Stubbs (1724–1806), Edwin Landseer (1802–1873) and Alfred Munnings (1878–1959) or the sculpture of G. F. Watts (1817–1904).

The range of topics that might arise from the ostensibly mundane series of tasks is boundless yet utilising the opportunity to exploit these for learning requires that the informal or outdoor educator possesses a deep appreciation of the theory and history of what they are teaching plus the facility to foster conversation and dialogue. In this context conversation must not be mistaken for idle chatter or banter which tends to manufacture winners and losers. Rather, it is what Michael Oakeshott calls 'an unrehearsed intellectual adventure' involving individuals freely coming together to share their thinking and experiences who are content to let thoughts 'take wing' [87]. It is this form of conversational adventure that accomplished informal and outdoor educators are equipped to nurture and nourish.

Of course, it does not end there. Eventually they will be taking the group riding in open country. At which point they will need to be armed with a knowledge, for example, of *fauna* and *flora*, agriculture, geology and local history. As the setting or group changes so will the mix of subject-matter to be drawn upon.

Alongside this concern with teaching and teachable moments, runs broader pedagogical stream. Pedagogy can be seen as a process of being alongside others or accompanying people as well as:

**Figure 2.** Animate, care, educate.

Many of the conversations in which pedagogues and informal educators participate involve questions that people have about how to deal with situations arising in their lives, relationships with others, and feelings about themselves. As Kerry Young [88] has pointed out, they involve the same question: how do I live life as well as I can? They are engaged with moral philosophy—and in a sense these conversations are the bread and butter of informal education and pedagogy. They require the ability to draw upon a broad range of knowledge. This includes:

This adds up to a formidable body of expertise.

Alongside all this there are practical tasks of helping and care (which in turn require knowledge, skill and a particular *haltung*). Tasks can range from sorting out food for them to eat, and clothes to wear, to direct physical assistance with mobility and other everyday actions. In these days of austerity with cutbacks in care budgets and growing poverty, many schools and community organisations have had to make a sustained response in these areas, and this has led to some fundamental questions about future priorities.

We are not implying that informal educators must be polymaths who know everything about everything. Rather, that they must be able to lay claim to a rich and broad general education and be an ardent scholar ceaselessly searching out new ideas, information, and experiences. We would argue that the essential starting point for those seeking to become a professional pedagogue and informal educator should be a three-year degree in the Liberal Arts comprising five key strands:

Undergraduate Liberal Arts programmes, which have long been popular in the United States, already exist in the UK, therefore the basis exists for the creation of such a model. Upon completion of the undergraduate programme potential entrants could then undertake a one-year post-graduate programme that focussed on pedagogy, teaching, and informal education.

It is here that the full implications of the failure of programmes to ground practitioners in the liberal arts, social sciences and moral philosophy become clear. It is not just that they have been sold short in terms of their ability to be teachers and pedagogues, they have also lost the chance to develop their subject knowledge. David Hume after reading the accessible yet informative essays of the journalist Joseph Addison vowed to ensure that henceforth he would endeavour to write with similar clarity so that he might become a 'a kind of resident or ambassador from the dominion of learning to those of conversation; and shall think it my duty to promote good correspondence betwixt these two states, which have so great a dependence on each other' [89]. This ambassadorial role is in essence the function of the informal educator. However, to fulfil that role they must be in possession of the learning required to make a meaningful contribution to the conversations they partake in.

### **9. Conclusions**

It is difficult to envisage that programmes of the sort discussed here will be unveiled soon. The demise of courses should not unduly amaze us. It has always been the case that the popularity of subjects wax and wane. For example, forty years ago there were over 70 undergraduate and postgraduate Humanics degrees running in North America. Linked to these were thriving university departments, scholarly journals, annual conferences, and a national accrediting body. Today nothing remains but a handful of stand-alone optional modules provided for under-graduate students by lone colleges scattered across the USA. To all intents and purposes, the subject has vanished from view. Similarly in the UK during the 1970s around a quarter of universities provided courses, nearly all postgraduate, in adult education. Most were designed to prepare students to work in a then thriving adult education sector. Today the courses and the sector alike have become all but extinct.

Given the decade long year-on-year fall in both the number of courses and students in attendance it seems likely that within a few years secular youth work education in the UK will suffer the same fate as adult education, play work and community work professional education. Christian youth work degree programmes may be all that remains, but their numbers have also dwindled, but at a markedly lower pace [90]. Whether or not that is the case, what might be loosely termed the 'informal education' sector within Higher Education is experiencing a period of prolonged crisis. Of course, that does not mean that informal education as an activity and pedagogical genre is teetering on extinction. Indeed, the current absence of an informal education presence in higher education should be viewed as an opportunity to think afresh regarding what it might be; to ask ourselves the crucial questions as to what might we expect a well-educated informal educator to know? Then, we can proceed accordingly.

**Author Contributions:** Jointly conceptualized, researched and written. Both authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** Figure 1 is reproduced with permission from Smith (2021) [81], Figure 2 from Smith 2019 [75].

**Conflicts of Interest:** The authors declare no conflict of interest.


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**3. Pest management**

Management strategies of greenhouse pests using chemicals were reported to result in several problems, such developments of resistance to chemicals by pests, and environmental and health problems are caused by those chemical pesticides [17]. The possibility of applying biological control programs to problems of greenhouse pests is highly recommended. Even though they will not completely solve the problems, they can reduce pest populations to an acceptable level. Biological control generally requires more time than pesticides to bring a pest population under an acceptable control level [18]. Biological control strategy such as releasing different predators and parasitoids was reported to be environmentally friendly production method of sweet pepper. Applying the biological control program resulted in a high yield of sweet pepper production (35.06%) compared with the control [17]. In this book chapter, various pest control methods are reviewed.

### **3.1 Polyethylene plastic cladding material**

The most commonly used material for greenhouse covering is polyethylene screening plastic, which has an ultraviolet-absorbing characteristic. The material was prepared by adding a specific UV-absorbing compound to raw polyethylene, which makes the plastic material that can stop the transmission of 95% of the UV light (200–380 nm) and transmits 80% of visible light (380–700 nm) [19]. The behaviors of insects can be affected by the modification of UV light. Light at 360–400 nm activates whiteflies (*T. vaporariorum*) to walk and fly [20]. Similarly, the effects of UV-absorbing plastics on thrips, *F. occidentalis*, have also been reported as hostfinding behavior is disrupted [21]. Reduction in reproduction in aphids by deactivation of its flying behavior was reported. For example, reproduction in *M. persicae* is significantly reduced in a greenhouse covered with UV-absorbent plastic [15].

### **3.2 Predators**

### *3.2.1 Phytoseiidae (Acari)*

Many phytoseiid mites are predatory, and several species have been developed as biological control strategies [3]. McMurtry and Croft [22] classify several phytoseiid mites based on their feeding behaviors. Type I species include *Phytoseiulus* spp., mites that are well known as predators of webbing spider mites. Type II mite species

include *Neoseiulus californicus* (McGregor) and *N. fallacis* (Garman), which feed spider mites and others. Type III species, for example, *N. barkeri* (Hughes), *N. cucumeris* (Oudemans), and *Iphiseius degenerans* (Berlese), are generalists that often prefer prey other than spider mites (in whose webbing they may become entangled) and thrips [3].


2. Analysis of aqueous solution complexes by different methods

There are other experimental techniques that we are going to give some examples for them in the following lines. The specific method for diamagnetic metal ion is the nuclear magnetic resonance (NMR). It gives one separated signal for each unique chemical surrounding. In other words, it can inform us about concentration of the ligand, the free metal ion, the number of species, and their concentration for a given chemical composition. The important feature of this technique is that the positions of these selective signals are responsible for the protonation and deprotonation ones. In the case of fast reactions, we can use a stopped-flow technique.

#### 2.1. The addition of water to iron(III)

It is observed that Fe3þ hydrolyses in water goes as follows:

$$\text{Fe}^{3+} + \text{H}\_2\text{O} \leftrightharpoons \text{FeOH}^{2+} + \text{H}^+ \tag{1}$$

The addition of water to Fe3þ is carried out through a series of deprotonation reactions, resulting in formation of ferric hydroxides and oxyhydroxides [12, 13] as in Eq. (1), the equilibrium constant for this reaction was calculated to be 6.78 � 10�3 at 298 K (total iron(III) concentration of 0.5 mol�dm�3 and an ionic strength of 0.1 mol�dm�3 ). Figure 1 shows the speciation of the two ironcontaining species of Eq. (1) as a function of pH, calculated at T ¼ 298 K. It seen that FeOH2þ will become the common species above pH ¼ 2.17. At lower pH, there are small amount of it; at pH value 1.2, more than 9% of all iron (III) is present as the hydroxide. As a result of that, the calculations for the spectroscopic measurements were carried out at pH values up to 1. The equilibrium constant for the reaction shown in Eq. (1) has been studied at temperature range from

iron intake and bioavailability. On the other side, they are responsible for only about half of the anemia in developing countries [10]. There are other important causes [11] like infectious and inflammatory diseases (especially malaria), blood loss from parasitic infections, and other

1. The first and most common method is ion-selective electrode. It defines the position of dynamic equilibrium. The most important electrode is the glass one. There is also hydro-

2. Metal amalgam electrodes are a second choice. It can be used for some metal ions, but they are not as precise as the hydrogen ion electrode. We prefer the ion-selective electrode in-calculation because the results are collected from series of data taken through a titration procedure. A good method to check for this prerequisite is to make repeated high-resolution electrode readings at predetermined time intervals, since this will make sluggish

3. Spectrophotometry can be used if the metal ion or the ligand is colored, so that the color

There are other experimental techniques that we are going to give some examples for them in the following lines. The specific method for diamagnetic metal ion is the nuclear magnetic resonance (NMR). It gives one separated signal for each unique chemical surrounding. In other words, it can inform us about concentration of the ligand, the free metal ion, the number of species, and their concentration for a given chemical composition. The important feature of this technique is that the positions of these selective signals are responsible for the protonation and deprotonation ones. In the case of fast reactions, we can use a stopped-flow technique.

The addition of water to Fe3þ is carried out through a series of deprotonation reactions, resulting in formation of ferric hydroxides and oxyhydroxides [12, 13] as in Eq. (1), the equilibrium constant for this reaction was calculated to be 6.78 � 10�3 at 298 K (total iron(III) concentration of 0.5

containing species of Eq. (1) as a function of pH, calculated at T ¼ 298 K. It seen that FeOH2þ will become the common species above pH ¼ 2.17. At lower pH, there are small amount of it; at pH value 1.2, more than 9% of all iron (III) is present as the hydroxide. As a result of that, the calculations for the spectroscopic measurements were carried out at pH values up to 1. The equilibrium constant for the reaction shown in Eq. (1) has been studied at temperature range from

Fe3þ þ H2O ⇋ FeOH2þ þ Hþ ð1Þ

). Figure 1 shows the speciation of the two iron-

nutrient deficiencies (vitamin A, riboflavin, folic acid, and vitamin B12).

gen gas electrode that can be used in hydrogen ion calculations.

will change (in intensity and/or frequency) upon complexation.

attainments of equilibrium clearly visible.

28 Descriptive Inorganic Chemistry Researches of Metal Compounds

2.1. The addition of water to iron(III)

mol�dm�3 and an ionic strength of 0.1 mol�dm�3

It is observed that Fe3þ hydrolyses in water goes as follows:

2. Analysis of aqueous solution complexes by different methods

Figure 1. The speciation of the two species of iron as in Eq. (1) as a function of pH at T ¼ 298 K for all the iron (III) concentration of 0.5 mol�dm�3 and an ionic strength of 0.1 mol�dm�3 .

T ¼ 298 to 353 K and ionic strength range from I ¼ 0.1 until 2.67 mol�dm�3 in perchlorate media [14].

For Eq. (1) to be done we must prevent the formation of hydrolyzed iron(III). This can be accomplished under the conditions of T ¼ 293–323 K, and I ~ 0.1 mol�dm�3 .

#### 2.2. How can you determine the stability constants of mixed ligand complexes

For inorganic chemistry, it is very important to determine the stability constant, or the equilibria constant or we can refer to it as the formation constant, for the reaction [15]. It is not easy to get the solution equilibria constants between the ligands and the metal ions. Proton ions and a range of metal ions fight for a range of donor sites. There are many factors that decide who will be the winner whether the proton ions or the metal ions. These factors are the concentration and pH. Potentiometry and spectrophotometry are used to determine the stability constants of metal complexes. Legget [16] and Meloum et al. [17] calculated the equilibrium constants from experimental data for the first time. Nowadays, many programs were published for these calculations using microcomputers. Table 1 presents some of these programs [15, 19–30]. These programs are very helpful as they quickly present the best fit. They use the least-square method to reduce the differences between calculated and experimental data. The sum of square of residuals between calculated and experimental values is very small; it is nearly between 10�6 and 10�9 . Potentiometry is used to determine the stability constants of metal complexes. It is based on pH-metric titration of the ligand, and the availability of metal ions. Data obtained from potentiometry are analyzed by the least-square method to derive the formation constant. This later can describe the solution equilibria. For the measurements, there must be two conditions: the first one is a constant ionic strength of the solution and the second condition concerns the ionic strength that have to be higher than the concentration of metal ion. The reaction of all mixed complex:

$$\mathbf{L(M)} + p(\mathbf{L\_1}) + q(\mathbf{L\_2}) + r(\mathbf{H}) \leftrightarrow \left[ (\mathbf{M})\_1 (\mathbf{L\_1})\_p (\mathbf{L\_2})\_q (\mathbf{H})\_r \right] \tag{2}$$

V, potentiometric experiments; A, spectrophotometric experiments; E, ESR; N, NMR. a Additional data used in calculations are taken from different sources.

Table 1. The programs commonly used for calculating formation equilibrium constants.

The total stability constant, βlpqr, can be calculated from the equation by:

β1pqr ¼ ½ MÞlðL1ÞpðL2ÞqðHÞr�=½M� 1 ½L1�p½L2�q½H� rðfor simplicity charges are omittedÞ ð3Þ

where M, L1, L2, and H stand for metal ion, ligand (1), ligand (2), and proton, respectively. For OH�, the coefficient (r) for H ¼ �1.

#### 2.3. Calculation of speciation

Pettit program computes speciation based on the concentrations of metal ions and the complexing species. This program specifies a certain pH range. Then the former calculates the species distribution of a certain series of complexes and plots it. We enter some data such as the total concentrations of metal and ligand ions and pH range. After that the best-fit set of β values will be used later to compute the equilibrium concentrations of those complex species over the pH range which we have specified before. We can use this program for all types of complexes: mixed complexes, protonated, hydroxo, and polynuclear species. The program produces a graphical recording of the most predominant complex species at any pH and the physiological pH range. In this chapter, we reviewed several iron complexes.


Meet the Volume Editors

Dr. Gopal Shukla, Ph.D., is a Professor of Forestry at North-Eastern Hill University, Tura Campus, Meghalaya, India. Before joining as a professor, he was Senior Assistant Professor of Forestry at Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal, India. Dr. Shukla has more than 12 years of teaching and research experience. He has worked on different projects, including the National Agricultural Innovation Project (ICAR), National

Innovations in Climate Resilient Agriculture (ICAR), and, as a young scientist, on the project on carbon stock of different land uses for the Science and Engineering Research Board, Department of Science and Technology, Government of India. His research interests include agroforestry, medicinal plants, forest ecology, and conservation. He has 90 research papers, 30 book chapters, and 8 books to his credit. He has successfully completed several research projects on forest ecology, medicinal plants, and agroforestry. Dr. Shukla has supervised four doctoral and six master's students.

Dr. Jahangir A. Bhat, Ph.D., is currently associated with the Piramal Foundation for Education Leadership at Piramal University, Mumbai, India. Before taking on his current position, he was associated with the College of Horticulture and Forestry at Rani Lakshmi Bai Central Agricultural University, India. Previously, he served as the head of the Department of Forestry at the College of Agriculture, Fisheries and Forestry, Fiji National University,

Republic of Fiji Islands. His research work in India and the Fiji Islands spans 12 years and encompasses emerging issues in forestry, including conservation of biodiversity, traditional knowledge of plants, and sustainable management of forest resources, particularly in the light of climate change scenarios. He has worked as a counselor, mentor, and coordinator for forestry academic programs and has been instrumental in developing higher education and technical and vocational education and training streams of forestry and allied programs. He worked closely for accreditation with the Fiji Higher Education Commission and forestry stakeholders.

Dr. Sumit Chakravarty, Ph.D., is a Professor and Head of the Department of Forestry, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal, India. He has more than 20 years of experience in forestry training, research, and development. He has conducted research on several aspects of forestry, agroforestry, medicinal plants, and climate change. He has published 120 research papers, 48 book chapters, and 8 books. He is

involved in fifteen research projects on forest ecology, medicinal plants, and agroforestry. He has trained more than fifty master's and doctoral students in forestry. Dr. Chakravarty has attended more than fifty national and international conferences as a presenter and invited speaker.

Dr. Adel W Almutairi, Ph.D., received his master's degree in biomedicine from Portsmouth University, UK. He obtained a Ph.D. in Molecular Biology and Biotechnology from Sheffield University, UK. His research aims to improve the productivity of microalgal biofuel production through different abiotic stresses and genetic engineering.

Dr. Mei Li, Ph.D., received her Ph.D. from Sichuan University, China, in 2012 and worked as an associate professor (major in Environmental Engineering) in Chengdu, China. She is engaged in non-point source pollution control, water environment assessment, and water pollution control. Dr. Li has published more than thirty research papers, three books, five patents, and two copyrights. She has presided over thirty scientific research projects at

the national, provincial, and bureau levels and successfully handled more than twenty projects. Dr. Li is the recipient of the Sichuan Province Environmental Protection Science and Technology Award.


**2. Related work**

CNNs are becoming more capable for image analysis application, due to the increasing number of layers and complex connections. However, adding more layers to increases performance produce more intricate models and higher computational cost. Eventually, deeper networks may start losing accuracy. On the other hand, MRA keeps all the information contained and distributed into its coefficients through the different resolution levels. Each one contains specific features; higher resolutions show more details and lower resolutions shows only the strongest features. In recent years, more studies have applied MRA to the CNN. Some of these studies are presented in **Table 1**, where the first two columns indicate the publication year and the application.

All the studies shown are applications embedded within the CNN to replace the pooling layers. The last three columns describe the kind of wavelet solution implemented. For example, the third column shows that Discrete Wavelet Transform (DWT), Lifting Scheme Wavelet Transform (LSWT) and Wavelet Package Transform (WPT) are the only wavelet transforms utilized in the analyzed studies. At the same time, the last three columns complete each model information by adding the wavelet family selected, the number of wavelet coefficients applied and the levels of decomposition. The wavelets used are families like Daubechies or Coiflet. The 2D wavelet transforms produce 4 coefficients and all analyzed models require the approximation coefficients. However, not all studies utilize the details coefficients.

**Table 1.** *Wavelets Transforms used to improve CNN pooling layers.*

In Ma et al. [24], the detail coefficients are used partially. In the last column indicates the number of levels of decomposition applied in each model. These studies introduce new frameworks with interesting results, like Bastidas-Rodriguez et al. [25], this model is embedded in a larger CNN to detect scenes and classify textures or compress images [24]. Other approaches also detect scenes and classify handwriting digits [26]. But, replacing pooling layers is the most common uses of wavelets within CNN like in Refs. [9–12, 23], as well as activation functions as reported in Refs. [27–31]. It is used for most of the previous applications, as well as for image restoration, lung tumors detection, among many more.

The aim of the study, initially inspired by Williams and Li [9], is to use the Wavelet Transform Coefficients randomly in a formal model as a pooling layer, to emulate the Max-pooling effect but independently from the signal's shape. Achieving a measurable increment of its accuracy using a benchmark dataset.


**Abstract**

Intermetallics are intermediate compounds formed between two metals. They are usually brittle. The presence of intermetallics leads to deterioration in mechanical properties. This chapter reviews the intermetallic compounds formed during the manufacture of lead-free alloys. Intermetallic compounds formed in ordinary lead-based alloys are also discussed. The role of rare earth, especially indium and lanthanum, additions on intermetallic formation is examined. Microstructures of intermetallics are analysed. Hardness values of lead-free alloys are compared with emphasis on type and nature of intermetallics. SEM photographs of lead-free solders are discussed with regard to type of fracture, and the role of intermetallics in nature of fracture is examined. Lastly, the general mechanisms of formation of intermetallics are touched upon, and these mechanisms are extended to intermetallic formation in lead-free alloys.

**Keywords:** lanthanum based alloy, indium based alloy, hardness, characterization

### **1. Introduction**

Intermetallic is a type of metallic compound that exhibits definite stoichiometric ratio of atoms. It also has a definite crystal structure. Their role is twofold. In small quantities, they can strengthen the soldering joint. However, when the amount of intermetallics increases, they may render the joint brittle. For example, La3Sn intermetallics are known to be present in lanthanum-based lead-free alloys. These are known to increase the hardness of the alloys. Ag3Sn, Cu3Sn and Cu6Sn are some known intermetallics in tin-, copper- and silver-based lead-free alloys. Mostly, the interaction of these intermetallics with the substrates has to be studied in detail in order to determine the exact effect on the solder properties. The growth of these intermetallics with time is determined by solid-state diffusion rules and varies from system to system.


**6. Conclusion**

Pyrolysis is thermochemical decomposition of biomass under inert environment. The products of this process are syn-gas, bio-oil and bio-char. These products are alternative to petrochemicals as they are good sources of renewable and eco-friendly energy and bio-chemical precursors for chemical and allied industry. Several factors including nature of biomass, biomass moisture content and design of pyrolyzer, others are vapor retention time, heating rate and degradation temperature determine quantity and quality of these pyrolysis products.

*Pyrolysis: A Convenient Route for Production of Eco-Friendly Fuels and Precursors for Chemical… DOI: http://dx.doi.org/10.5772/intechopen.101068*


Preface

Strawberry is the most popular fruit in the world and a good source of bioactive compounds, providing human health benefits. It also contains considerable amounts of vitamins, minerals, flavonoids, and phenolic acids.  Thus, it needs careful management to maintain its quality. Preharvest production factors should also be considered for high-quality strawberry production. Fruit harvest practices and postharvest techniques of strawberry fruit greatly affect its quality.

This book mainly deals with pre- and postharvest management practices of the strawberry to ensure that high-quality fruits are delivered to the consumer. The influence of climatic variables, cultural practices, harvesting techniques, and use of chemicals and other natural compounds on fruit quality are discussed. Factors affecting fruit growth and development and processes regarding maturation and biochemical changes during fruit ripening are also presented in one of the chapters of this book. Some chapters provide information regarding harvesting, storing, packaging, transporting, and also selling that affect strawberry quality greatly. Enhancement of yield and antioxidant contents in the strawberry by various natural products, including chitosan and probiotic bacterial, are also included in this book. The final chapter states that antioxidants present in strawberry fruit play a dietary role in alleviating oxidative stress in experimental liver models.

Recent research work on nutritional quality, culture practices, and pre- and postharvest management techniques of the strawberry are brought together in this book to further the field of plant biological science. Publication of this book would have been impossible without the contribution of many researchers around the world. Our sincere acknowledgment goes to the authors who contributed their valuable research work to this book.

> **Dr. Toshiki Asao** Department of Agriculture, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan

#### **Dr. Md Asaduzzaman**

Horticulture Research Centre, Bangladesh Agriculture Research Institute, Gazipur, Bangladesh

**1**

**Chapter 1**

**Abstract**

Strawberry

of strawberry is discussed.

**1. Introduction**

ing these factors [1].

The Effect of Preharvest Factors

*Toktam Taghavi, Rafat Siddiqui and Laban K. Rutto*

**Keywords:** strawberries, cultivar, genetics, environment, light, nutrition,

Several reports confirm significant (35–50%) loss in horticultural produce after harvest. These losses are mainly due to dehydration, decay, and physiological disorders during postharvest handling. Fresh products also undergo rapid changes in nutritional and sensory quality after harvest, some of which contribute to loss of market value [1]. Losses can be mitigated through better management of pre- and postharvest factors. Differences in postharvest loss of fresh produce between developed (5–35%) and developing countries (30–50%) as reported by Kader [2], Salami [3], Kitinoja [4], and Ray and Ravi [5] are due to the higher capacity and better infrastructure in developed economies for manag-

In strawberry, preharvest management is a prerequisite for producing good quality fruit. Quality deterioration starts as soon as the produce is harvested, and postharvest factors can only maintain but not improve the quality. The growers' decisions and management directly affect the final market value of strawberry and its acceptance by the consumers [1]. Many preharvest factors affect fruit quality at harvest. In this review, we will discuss genetic variability, climatic conditions, and

temperature, soluble solids, acidity, firmness, fruit quality

cultural practices that affect quality of strawberries.

on Fruit and Nutritional Quality in

Strawberries play an essential role in human nutrition and health, especially as a source of vitamins, minerals, and dietary fiber. They also have health-promoting compounds that lower the risk of cancer and cardiovascular disease. The nutritional value of strawberries varies greatly among cultivars. Traditional and molecular breeding techniques can be used to develop varieties with enhanced nutritional quality and improved flavor to meet consumer preferences. Climatic conditions, such as temperature and light intensity, and other preharvest factors, e.g., soil type, fertilization, irrigation, mulching, and other cultural practices, have a significant effect on strawberry fruit quality. Additionally, the extent of postharvest physical and physiological injury and potential fruit loss is affected by preharvest parameters. In this chapter, the effect of preharvest factors on fruit and nutritional quality