*3.1.2 Vessel structure*

According to the vascular bundle structure presented in **Figure 7**, the presence of large vessels varies from one to three vessels. The term of large vessel here is the tracheary elements of a vascular bundle like the oil palm trunk [35]. The extensive surveys of tracheary elements in palms are conducted by Tomlinson [30], and Bierhorst and Zamora [37], and these studies can be applied to oil palm fronds. Further, Parthasarathy and Klotz [28] found the palm vascular bundle clusters tracheary elements display a gradation in morphology from protoxylem within beginning to final metaxylem. The end walls of the tracheary part manifest a rising degree of evolutionary specialization, i.e., they enhance decreasingly tracheid-like. The protoxylem tracheary parts and any of the narrow early metaxylem elements approximately evermore appear to be tracheids. The remaining thin metaxylem elements and the broad late metaxylem elements present varying degrees of specialization, depending on the organ and the species.

Large vessels with very thick vessel-wall were predicted as the main component responsible for transporting the nutrient. This statement was in agreement with the result from Lim and Khoo [33] that has been studied on the oil palm trunk. **Figures 8** and **9** show the vessel on a close view in the vascular bundle from two different sectional views at transverse sectional and at the longitudinal views.

#### *3.1.3 Fibre structure*

The oil palm fronds consist of primary vascular bundles embedded in parenchyma ground tissues. Oil palm fronds fibres spread beyond the vascular bundles and loaded by the parenchyma cells. Fibres have a tight end, mainly influenced. The composition of fibres was essentially comparable to common woods, including softwood and hardwood, which comprise pits, cell walls, and lumen. Fibres in the oil palm fronds played a vital role in the strengthening mechanism of the composite when stress was transferred between the matrix and fibres. The SEM of fibres contains in vascular bundles is displayed in **Figures 10** and **11.**

#### **Figure 8.**

*SEM of the vessel in oil palm fronds at the transverse sectional view (700 magnification).*

#### **Figure 9.** *SEM of the vessel in oil palm fronds at the longitudinal sectional view (460 magnification).*

The transverse sectional view of oil palm fronds in **Figure 10** shows that the fibres attached to the others in very compact formations like fibres in oil palm trunk. **Figure 11** presented the structure of the fibre in oil palm fronds closely. Various sizes and shapes were distinguished, e.g. spherical, triangular, and rectangular. The presence of pits also identified at the fibre wall and companion cells, like shown in **Figure 11**. The walls might be thick or thin, and the small or large lumina. The primary function of fibres was predicted to provide strength support to the living oil palm fronds.

## *3.1.4 Parenchymatous tissues*

Parenchymatous tissues are not only found in the trunk but also found abundantly in the fronds. They are food storage elements and must, therefore, remain alive for an extended period. Similar to vascular bundle shapes, parenchyma tissues show two different forms, which are isodiametric-shape and elongatedshape. The isodiametric cells have thin walls, while the elongated cells have thicker *Processing and Properties of Oil Palm Fronds Composite Boards from* Elaeis guineensis *DOI: http://dx.doi.org/10.5772/intechopen.98222*

**Figure 10.** *SEM of fibres in oil palm fronds at the transverse sectional view (500 magnification).*

#### **Figure 11.**

*SEM of fibres in oil palm fronds at the transverse sectional view (2500 magnification).*

poly-laminate walls [38]. Parenchyma tissues are also found associated with the vascular bundles in the axial position, an elongated shape. They are found at the inner tip of the vascular bundles related to the vessels, protophloem, and protoxylems. They may have a special function in water transport, like the vessel-associated cells in the dicotyledonous trees [33]. These parenchymatous tissues consist mainly of ground parenchyma, parenchyma strands, sieve elements, and companion cells [36].

The parenchymatous ground cells consist mainly of thin-walled spherical cells, except in the vascular bundles. The walls are progressively thicker and darker from the inner to the outer region. Parenchyma tissues contain much sugar and starch as food storage elements, which are soluble in water and NaOH [39]. Parenchyma cells of oil palm fronds functioned as the ground tissues that make up the bulk of oil palm fronds structures and are used as storage for food. Parenchyma cells of oil palm fronds were mainly in the form of spherical cells with thin-walled and brick-like formations, but in the narrow space or area between vascular bundles, they were familiar as elongated cells and oval-cells, and this is similar to oil palm trunk. Physically, this tissue was spongy and moist in green condition and very lightweight and easy to separate one cell from the others. Parenchyma cells also contain some amount of chemical composition [40]. **Figure 12** shows detail of the structure of parenchyma cells under SEM.

**Figure 12** shows that many pits were observed on the primary cell wall, which functioned for water or nutrient transport purposes. Based on this fact, it is logically accepted why ground parenchymatous tissue was very hygroscopic. It was easy to evaporate when the temperature is rising and also easy to absorb the moisture in high humidity conditions. A study by Tomimura [41] and Sun et al. [42] found that parenchyma contained a high amount of starch and lignin compared to vascular bundles. Besides, parenchyma ground tissue which cements the vascular bundles together is undesirable for the manufacture of wood-based products like pulp and composite boards. In pulp manufacture, these tissues consume chemicals and produce fines that may be lost during screening. The rounded parenchyma also reduces the paper strength properties. In particleboard manufacturing, it may interfere with the bonding between particles and will reduce strength properties.


Factors Affecting Household Goat Farmers' Market Participation and the Extent of Commercialization

*Zamokwakhe Maureen Ntshangase,Tafa Sanelise, Bethwell Moyo, Sikwela Misery and Johan Van Niekerk*

### **Abstract**

This paper assessed the factors influencing farmers' choice to participate in selling goats and the extent of goat commercialization in Zululand district of Kwa-Zulu Natal Province in South Africa. Data were collected through questionnaires administered to 175 selected goat farmers in five local municipalities within Zululand district. A Probit model was used to estimate the factors affecting farmers' choice to commercialize while Tobit regression model was used to analyze the factors affecting the extent of commercialization. The Probit results show that the factors that positively and significantly affect farmers' choice to commercialize are gender, education level, quantity of goats, and type of marketing channel. The Tobit results revealed that factors that have a positive significant effect on commercialization are gender, level of education, experience in goat farming, and time of the year. The paper recommends that government support programs should be promoted to achieve high goat production and establishment of formal marketing goat sector to promote commercialization. Furthermore, information about goat nutritional attributes must be effectively shared with the society to change the negative stigma towards goats thus increasing the demand for goat and goat products, thus increasing farmers' market participation and promoting commercialization.

**Keywords:** goats, market participation, commercialization, sustainability

#### **1. Introduction**

Goat farming in South Africa (and other parts of Africa) has been the most extensive agricultural sector since the beginning of the 19th century. It is believed that goat population grows along with the human population. One of the reasons for a growing population of goat farming in Africa is that it is a farming sector that does not require intensive investment. For that reason, most South African farmers see goat farming as one of the strategies to curb food insecurity, for it is in high demand in the informal market.

However, the surprising thing is that goat farming is regarded as a poor man's trade. It is characterized by informality, lack of industry determination, value addition, and modern distribution channels. Very few farmers sell their goats through abattoirs, because most producers rely on consumers who are driven by cultural and traditional beliefs.

This chapter presents the factors affecting goat farmers' market participation and the extent of commercialization. The chapter is set out as follows; the next section defines the problem, followed by the methodology. After that, the discussion of results are presented, followed by the conclusion.

### **2. Definition of problem**

There are very few large scale commercial goat farmers in Africa, and most of them are found in South Africa [1]. In South Africa, a large number of indigenous goats are owned by small-scale farmers found mainly in communal areas [2]. The white commercial farmers mainly rear Boer and Angora goats [3]. The goat resource in South Africa, which is mainly owned by non-commercial farmers and mostly of indigenous breeds is large enough to ensure a consistent supply of product to the market.

Goats significantly contribute to the country's goat population as it is approximately 63% [4]. Goat commercial farming is predominant in the Eastern Cape, followed by Limpopo then Kwa-Zulu Natal (KZN) Provinces of South Africa. Eastern Cape has more goats in South Africa accounting for 38% of the total flock followed by Limpopo with 18% and KwaZulu–Natal with 13% [5]. However, there is a potential to develop goat production in KZN as according to [6], more than 50% of cattle, 19% of sheep, and 74% of goats are on communal lands in the KZN province.

It is noteworthy that, goat marketing remains very low and informal in South Africa and this is exacerbated by low participation of goat farmers in formal markets [7]. One of the contributing factors to low market participation is that most goat farmers are mostly in rural areas where goats depend on the natural forage under extensive conditions throughout the year without nutritional supplements during the winter dry season. In general, smallholder farmers' productivity is low due to factors such as lack of information, lack of market access, and poor access to support services [8–10].

These factors are challenges in the improvement of smallholder production and thus smallholder producers are finding difficulties in commercializing their production. The major challenge to commercialization is how smallholders can penetrate and participate in markets [11]. Sharma et al. [12] also found out that participation in the commercialization process has been difficult for smallholder farmers because of inappropriate policies, insufficient access to technology, institutional obstacles, weak infrastructure, and unfortunate links to markets. In the past 18 years, the South African government implemented several policies and programmes and increased the agricultural sector's budget by supporting emerging farmers [13–15]. However, very little is known about smallholder goat farmers or goat production in general. The resistant nature of goats to disease and internal parasites, its adaptability to harsh conditions, less production cost, and easy increase of production because of the high possibility of twining makes goats more sustainable livestock to produce by smallholders thus demanding a commercial approach from farmers.

According to [16], smallholder commercialization is part of an agricultural transformation process in which individual farms shift from a highly smallholderoriented production towards more specialized production targeting markets for their input procurement and output supply. According to [17] agricultural commercialization is the basis of economic development and integration of farm household into rural economy and society as an integral part of the process. Furthermore, [18] also assert that the transition from subsistence to commercial agriculture represents a key ingredient for low-income countries' economic development.

#### *Factors Affecting Household Goat Farmers' Market Participation and the Extent… DOI: http://dx.doi.org/10.5772/intechopen.97233*

Therefore achieving goat commercialization will enhance the welfare as well as economic development for smallholder farmers. Notable, commercialization as an agricultural transformation will therefore have a substantial impact on agricultural production, food security, poverty alleviation, and economic contribution to the smallholder farmer at a household and a national level.

Goats are predominantly sold live for cultural and religious ceremonies and traditionally goats have served as a means of ready cash and a reserve against economic and agricultural production hardship [19]. However, the evolution in the meat industry and consumer health requirements are slowly creating an entrance for goats in the formal market since goat meat is now available in some retail stores in Eastern Cape, Gauteng, and in very few outlets in KZN [4]. Most goat products are exported to countries like Asia where they are mostly used and are in high demand than in local use [20, 21]. Despite the exporting marketing opportunities, smallholder farmers still have no access to these markets because of various production and marketing constraints they face. Producing for the formal market requires production resources such as land, water, on farm and off-farm infrastructure, labour force, capital, and good management skills [15, 22]. Poor access to these resources by household farmers affects how they may benefit from opportunities in agricultural markets hence lack of resources also hinders the commercial approach in goat production and marketing.

Globally, livestock production systems are undergoing rapid changes in response to population growth, urbanization, and increasing incomes [23]. The demand for livestock is largely influenced by socio-economic factors such as human health concerns, constantly changing socio-cultural values and rapidly increasing population. As such the increasing demand for the animal products is expected to improve the income and livelihood of smallholder farmers who account for the bulk of production in developing countries [23, 24]. However, most of the increasing livestock production is taking place outside the smallholder sector, which is the same trend with goat production. Goat meat matches consumer preferences for low-fat meat and consumer concerns on health [20, 21]. Therefore goats have the potential for being a diverse reservoir for future use if commercialization is achieved.

The problem investigated in this study relate to the farmers' choice to participate in goat selling and goat commercialization. Commercialization means a change from a subsistence type of production to a market-oriented to profit maximization [25]. Therefore, commercialization can transform smallholder goat farmers by shifting production practices from current consumption-oriented towards marketoriented thus achieving economic development through income growth. The question which can be asked is whether the household farmers do participate in marketing goats, the level of participation, and which market do they use to sell goats. Therefore, this chapter aim at identifying the factors affecting farmers' choice to participate in the marketing of goats and determine the extent of goat commercialization in the study area.

### **3. Methodology**

#### **3.1 Description of the study area**

This study was conducted in Zululand district municipality, (ZDM) which is situated in the northeastern part of KZN. Zululand District Municipality is the biggest district in the province, making up 16% of its geographical area. The ZDM covers 14810km2 and consisting of 803576 population size in total and 102982 people of the entire population are unemployed hence the level of poverty in the

area is very high amounting to 33, 02% [26]. Approximately half of the area is under traditional authorities' jurisdiction while the remainder is divided between commercially owned farmers and conservation areas [26]. The ZDM district municipality comprises five local municipalities: Ulundi, Abaqulusi, Edumbe, Nongoma, and Pongola.

#### **3.2 Sampling and data collection**

The target population of the study was the household goat farmers in Zululand district in KZN province. Purposive sampling was performed in this study. One hundred and seventy-five goat farmers were randomly selected from the five local municipalities with 35 goat farmers from each municipality. Structured questionnaires were used to collect data through face-to-face interviews with goat farmers in the Zululand district. As household farmers did not have records, this study counted on farmer's recall for information.

#### **3.3 Data analysis**

Frequency and econometric analyses were done to analyze the data. Percentages were used to analyze the demographics of farmers. This study's socio-economic characteristics include gender, age, race, marital status, level of education, and employment status.

A Probit model was used to estimate the factors affecting the choice of commercialization. [27] asserted that when the Probit model is used to analyze the farmers' decision to participate in the output market, it has to be estimated as follows:

$$\begin{array}{l} Y\_i = \beta\_0 + \beta\_1 \text{Age} + \beta\_2 \text{Gender} + \beta\_3 \text{Race} + \beta\_4 \text{Marrital status} + \beta\_5 \text{Education} \\ \rightarrow \beta\_6 N.\text{Liver stock} + \beta\_7 \text{Martert channel} + \beta\_8 \text{Farm ass.} + \beta\_9 \text{Det. price} + e\_i \end{array} \tag{1}$$

Where:

Yi is dependent variable, which is the choice to participate or not. It can take 1 if the farmer participate in commercialization and 2 if otherwise.

In order to analyze the factors affecting the extent of commercialization, Tobit regression model was used. This Tobit model was developed by Tobin in 1958. Tobit was chosen because it uses censored dependent variable as the information is available for certain respondents. Some studies have used the Heckman model to fulfil the same objective; however, Heckman is not efficient compared to the maximum likelihood of the Tobit Model. Tobit Model specification is as follows:

$$\begin{array}{l} \text{Y}\_{i} = \beta\_{0} + \beta\_{1}\text{Age} + \beta\_{2}\text{Gender} + \beta\_{3}\text{Race} + \beta\_{4}\text{Marital status} + \beta\_{5}\text{Education} \\ \quad + \beta\_{6}\text{N.Livestock} + \beta\_{7}\text{Market channel} + \beta\_{8}\text{Farm ass.} + \beta\_{9}\text{Det. price} + u\_{i} \end{array} \tag{2}$$

Where Yi presents the number of traded goats.

#### **4. Results and discussion**

#### **4.1 Introduction**

This section presents the results first and foremost. The objective was to assess the factors affecting household goat farmers' market participation and the extent of commercialization. The first sub-section presents the socio-economic profile of the

goat farmers in the study area. The second section provides the empirical results, where tobit and marginal effect results are discussed.

### **4.2 Goat farmers' socio-economic profile**

The significant of demographic information in academic research cannot be overemphasized. The socio-economic factors exert pressure on the decision making behaviour of a household. This study's socio-economic factors are gender, age, marital status, level of education, race, experience, and membership status in the farmers' association (see **Table 1**).

The Zululand population is predominantly black/African. For that reason, most respondents in the study area were Africans (98%), while the remaining 2% was made up of white respondents (see **Table 1**). Majority of African farmers were

## **Table 1.**

producing for subsistence purposes, while the white farmers were solely producing for commercial purposes.

It is important to note that in most African settings, male gender usually likes to keep livestock compared to females. Females predominantly look after crop production. Hence the results presented in **Table 1** reveal that Zululand farmers are made up of 75% male, and 25% females. The findings reveal that goat farming is dominated by males than females in the study area. Furthermore, the greater number of male respondents could also be attributed to the cultural ideology that males are the heads of the families and therefore own livestock and are often the ones answering questions in the survey despite the possibility of a wife being the owner of the goats in the household farm.

This study also reveals that older farmers are dominating goat farming when compared to the younger generation. 53% of respondents were between the ages 50 to 61, while the 31 to 40 age category comprised 33% and 13.5% were in the category of 18 to 25 years. Generally, young people are more likely to migrate in search of non-agricultural jobs whilst older people remain at home and do agricultural activities. Furthermore, the author assumes that youth with higher educational qualifications are always hesitant to engage in agriculture as a primary means of livelihood unless commercially available. In addition, climate change and the rapid increasing population demand for the transfer of food production activities and knowledge to young and literate society members. However, the limited participation of youth in goat farming is a concern for sustainable goat productivity and commercialization considering the level of chronic illnesses threatening the aging farmers and the high rate of youth unemployment.

Though education impacts farming, it is clear in this study that household farmers take it for granted, particularly with goat production as an average number of respondents without formal education participate in goat farming. Most (33,5%) of the respondents of goat farmers in the study area attended primary school, followed by secondary education with 22%, while 18% of the study population had matric and only 6% had tertiary education. 19% of the study population did not have formal education. These findings further confirm that most South African smallholder farmers have limited education and the lack of awareness among rural farmers can be attributed to the high level of illiteracy.

Regarding employment, less than 10% of the respondent were employed, the majority (64%) are getting state grants and not employed, followed by 26% who are unemployed. From these findings, it is clear that unemployment is one of the challenges facing rural goat farmers.

Marital status affects decision making in any household. In most cases, married farmers usually have children to take care of, which affects their decision because they have to invest in their families' future. This is why most goat farmers in Zulaland are 59% of the Zululand married farmers, while 38% single, followed by those who are widowed (3%). Membership in a farmers' organization is essential for every farmer's development. A farmers' organization is vital because it is where challenges facing farmers are mostly discussed. Results presented in **Table 1** show that most farmers in Zululand are not members of an organization.

#### **4.3 Factors affecting the goat farmers' choice to commercialize**

**Table 2** shows the factors affecting goat farmers' choice to commercialize in the KZN area. These factors range from gender, age, marital status education level, market channels among others.

Gender plays a crucial role in the decision of whether to produce for commercial purposes or subsistence. This is because of the distribution of economic roles within

*Factors Affecting Household Goat Farmers' Market Participation and the Extent… DOI: http://dx.doi.org/10.5772/intechopen.97233*

*Source: Author's computation (2021).*

#### **Table 2.**

*Factors affecting the goat farmers' choice to commercialize.*

a household. For example, roles that require physical strength are given to men while those that do not, are given to a females. The results revealed a significant relationship between gender and the decision to commercialize at p < 0.05 (see **Table 2**). African cultural norms that perpetuate the perception that livestock ownership is a responsibility of men also contribute to this finding. Therefore livestock gender ownership greatly influence goat commercialization.

Furthermore, the results revealed that education level significantly affects commercialization choice at 5%, positively. The influence of education in adopting new technologies by farmers is generally prominent [28]. On the same note, [29] argued that education is one of the most significant demographic characteristics for decision-making among farmers, for it directly improves knowledge capacity, the ability to understand and instantly make sense of information. The higher the level of education the more the chances of adopting new technology [30]. In this case, it is clear that the high literacy level can strengthen or enhance goat production because literate communities are more likely to take risks and thus more inclined to commercialize and quickly adopt new technologies.

This study's findings further reveal that the number of goats owned by the household was observed to be an important factor influencing the commercialization of goat for meat production with a statistical significance of P < 0.001. Households with large herds sold significantly more goats on average than those with medium and small herds. Such households presented a significant source of goats for the market and they could, therefore, be a target group for commercialization. These findings are in line with [31]'s arguments who noted that the insufficient number of goats amongst farmers with small herds restrict sale.

The results also revealed a significant relationship (P < 0.05) between the market channel type and commercialization choice. Thus, large numbers of goats are sold through informal market directly to the available consumer by the household farmer thus allowing the farmer to retain 100% of the selling price in the absence of a formal market. The large use of the informal market for goat sales in this study is not uncommon. There is nevertheless an enormous potential for the sale of goat meat as an additional source of income on farms. According to [24] despite the economic importance of goats, particularly in the sustenance of household food security in rural areas of developing countries, marketing of goats and chevon is not as formalized as that of other livestock.

#### **4.4 Factors affecting the extent of goat commercialization**

Tobit results are presented in **Table 3**, with marginal effect.

Tobit results presented in **Table 3** above indicate that gender was statistically significant at 10% with a positive influence on the extent of commercialization amongst the farmers. This positive relationship between gender and the extent of commercialization is inconclusive since any of the gender can commercialize. The marginal effect presents that gender affects the level of commercialization by about 9%. Age was also found to affect the level of commercialization at 10% positively. These results imply that an increase in age of a farmer has a high probability of increasing the extent of commercialization by 23.8% (presented by marginal effect). Many studies have concluded that age signifies the level of experience of a farmer. Moreover, farmers with more experience tend to participate in the market.

Levels of education significantly affect the extent of commercialization at 5%. The positive coefficient shows that the more educated a farmer becomes, the high possibility of commercializing their goat production. The results are in line with [24] who stated that educated farmers are more likely to participate in marketing of their products. This is because educated farmers are more likely to know the available marketing channels. Similarly, [32] attest that illiteracy affects one's ability to

*Source: Author's computation (2021).*

#### **Table 3.**

*Tobit results and marginal effects.*

*Factors Affecting Household Goat Farmers' Market Participation and the Extent… DOI: http://dx.doi.org/10.5772/intechopen.97233*

access important agricultural market information (such as price updates) and fair marketing commitments. Illiteracy does not involve the inability to read and write only, but also inability to interpret agricultural market information. It is acknowledged that farmers with basic education are more likely to adopt new production technology and this impacts the number of goats produced and consequently market participation. Pienaar and Traub [33] indicate that most of the farmers in South Africa have 5 years of education (an equivalent of grade 5). The modern production technologies needed to increase agricultural production tend to be composite for the illiterate farmers, who are, therefore, less likely to adopt them. Therefore, the level of education has major implications for agriculture production since it is going through a series of innovations and development demanding a better-educated farmer. In addition, education influences the ability of farmers to adopt new marketing information and technology.

The time of the year presented in **Table 3** above signifies the season. It is significant at 10% but has a negative influence on the extent of commercialization of goat. The results are in agreement with the fact that goat meat is usually in high demand during traditional ceremonies. These traditional ceremonies usually take place during the holidays of April, June, and December. For that reason, most farmers do not sell their goats when they are not in demand. Domestic consumption of fresh goat meat for only traditional and religious ceremonies is the primary challenge for goat farmers as they are unable to sell throughout the year.

### **5. Conclusion and recommendation**

Socio-economic factors have an impact on both farmers' choice and the extent of commercialization in the study. The study reveals that older farmers with experience are the ones likely to participate in the market. Educated farmers are also highly likely to participate in the market because they can access and be able to interpret marketing information. Age and level of education affect the number of goats owned and market participation. Level of education and experience enables the farmer to effectively manage goats thus achieving high productivity, as it is also easy for educated farmers to adopt new technologies that will improve production. Therefore there is a great positive relationship between productivity and market participation which consequently influences commercialization. It is noted in the study that the farmers use the informal market to sell their goats live and socioeconomic issues largely influence the marketing as goats are sold in certain specific months which is the period where certain cultural, tradition or religious ceremonies are performed. There are no formal markets for goats and goats products, this is an issue as farmers depend on the available informal market which is not structured thus farmers in the study area have no choice to whom they sell their goats to.

The study reveals that a skilled and educated goat farmer participates in the market. Therefore, government programs that will train and skill goat farmers must be established to increase productivity and market participation. Market information is an important aspect of agricultural development as it enhances market performance and knowledge of market actors. Furthermore, training programs are important for adopting production and marketing technologies, thus enhancing rural goat farmers' productivity. Through the training programs, effective goat marketing strategies could be developed to inform consumers about attributes of goats to address the sociocultural stigma attached to goat and allow goat products to be accepted as an alternative protein source and this will allow goat sales to be throughout the year consequently achieving sustainable commercialization of goats. The goat product potential that is somehow overshadowed by cattle, sheep, and pig products will be illuminated by establishing formal markets. Training programs will also assist farmers in understanding the demand, price trend, and dynamics in consumer preferences. The study further reveals a positive relationship between market participation and productivity, therefore it appears that the quantity of goats is among the leading significant drivers thus efforts to increase production abilities are very important to promote commercialization of household farmers.

This study recommends that a pathway be created to support household goat farmers so that viable conditions to shift from subsistence farming to marketoriented farming are established. Government support for goat farmers will be imperative in this regard. The study also recommends establishing formal market structures where goat farmers can sell their goats and goat produce to promote market participation and, consequently, increase food security and poverty alleviation for rural farmers. Government support in establishing the formal market for goats will be of high importance as in return revenue could be collected from farmers thus contributing to the country's economy. The increasing evolution in consumer preferences and health consciousness is important for diffusion innovation and exploitation of new markets for goat products thus achieving commercialization. Climate change makes goat husbandry the main feasible economic and productive activity in mountain areas of South Africa, where the climatic and soil conditions hinder the sustainability of other livestock-rearing activities. Goats can effectively provide environmental and socio-economic services sustainable if well managed and also if there is a structured market for goats. It is noteworthy that the economic value of goats can be realized through commercial production and marketing of goat as well as through value-adding to goat products. There is therefore a need to explore vast marketing opportunities both local and international and at the same time improving goat production towards a commercial approach so as to ensure reliable supply and sustainability of these new markets.

### **Acknowledgements**

The authors wish to thank their respective institutions for the material used and intellectual support.

#### **Author contributions**

All authors contributed in writing the paper.

### **Funding**

This research received no external funding.

#### **Conflicts of interest**

The authors declare no conflict of interest.

*Factors Affecting Household Goat Farmers' Market Participation and the Extent… DOI: http://dx.doi.org/10.5772/intechopen.97233*

### **Author details**

Zamokwakhe Maureen Ntshangase1 \*, Tafa Sanelise2 , Bethwell Moyo2 , Sikwela Misery3 and Johan Van Niekerk1

1 Centre for Sustainable Agriculture, Rural Development and Extension, University of Free State, Bloemfontein, South Africa

2 Fort Cox Agriculture and Forestry Training Institute, Middledrift, South Africa

3 Department of Public Administration and Economics, Mangosuthu University of Technology, Durban, South Africa

\*Address all correspondence to<EMAIL_ADDRESS>
© 2021 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.

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[15] Khapayi, M. And Pelliers, P. R. (2016). Factors limiting and preventing emerging farmers to progress to commercial agricultural farming in the king William's town area of the Eastern Cape Province, South Africa. *S Afr. Jnl. agric. ext.* [online]. 2016, vol.44, n.1], pp.25-41. Available from: <http://www. scielo.org.za/scielo. Accessed November 2020

*Factors Affecting Household Goat Farmers' Market Participation and the Extent… DOI: http://dx.doi.org/10.5772/intechopen.97233*

[16] Jaleta, M., Berhanu Gebremedhin B., and Hoekstra D., (2009). Smallholder commercialization: Processes, determinants and impact. Discussion Paper No. 18. Improving Productivity and Market Success (IPMS) of Ethiopian Farmers Project, ILRI (International Livestock Research Institute), Nairobi, Kenya. 55 pp

[17] Poole, N. (2017) Smallholder Agriculture and Market Participation, Rugby, UK: Practical Action Publishing,

[18] Carletto, C., Corral, P. and Guelfi, A., 2016.Agricultural commercialization and nutrition revisited: Empirical evidence from three African countries. Food policy Vol.67: 106-118. Doi: 10.1016/j.foodpol.2016.09.20

[19] Zewdie B, Welday K, 2015. Reproductive Performance and Breeding Strategies for Genetic Improvement of Goat in Ethiopia: A Review. Greener Journal of Agricultural Sciences, 5(1):023-033, http://doi.org/ 10.15580/GJAS.2015.1.080614317.

[20] Monteiro, A., Costa, J.M.and Maria Joao Lima M.J., 2017. Disadvantages to the Animal, Environment and Farmer: Goat System Productions: Advantages and disadvantages to the Animal, Environmental and Farmer, Goat Science, Sandor Kukovies, IntechOpen, Doi:105772/intechopen.70002

[21] Mzhangara, I.R., Chivaandi E., Mupangwa J.F., and Muchenje V., 2019. Goat Meat in the Red Mead Industry. Sustainability 2019, 11 (13), 3671; h ttps://doi.org/10.3390/su1113367

[22] BALOYI, J.K., 2010. An Analysis of Constraints facing Smallholder Farmer in Agribusiness value chain: A Case Study of Farmers in Limpompo Province. University of Pretoria.

[23] Ngambi, J.W., Alabi, O.J. , and Norris, D.; 2013. Role of goats in food security, poverty alleviation and

prosperity with special reference to Sub-Saharan African: A review. Indian Journal of Animal Science Research, 47 (1)1-9

[24] FAO. 2015. Understanding smallholder farmer attitudes to commercialization – The case of maize in Kenya. Rome.

[25] Abdullah A, Fazli Rabbi B , Riaz Ahamad C , Sajjad Ali , Abbas Ali, Chandio A , Waqar Ahmad , Aasir Ilyas A , Izhar UD & Din E. 2017. Determinants of commercialization and its impact on the welfare of smallholder rice farmers by using Heckman's twostage approach. Journal of the Saudi Society of Agricultural Sciences, available at http://dx.doi..org/10.1016/j. jssas.2017.06.001. Accessed on December 2020.

[26] Integrated Development plan, 2017. Zululand District Municipality.

[27] Egbetokun, O. A., Omonona, B. T., 2012. Determinants of Farmers' Participation in Food Market in Ogun State, Global Journal of Science Frontier Research Agriculture and Veterinary Sciences, vol. 12, no. 9, Version 1.

[28] Singh K., 2000. Education, technology and agricultural productivity. Indian Journal of Agricultural Economics, 55, 3

[29] Abera, G. (2009). Commercialization of Smallholder Farming: Determinants and Welfare Outcomes. A cross-sectional study in Enderta District, Tigrai, Ethiopia. Thesis , University of Fort Hare, Eastern Cape South Africa

[30] Haji, J., Aman, M. and Hailu, T., 2013. Impact analysis of Mede Telila Small Scale Irrigation scheme on house poverty Alleviation: Case of Gorogutu District in Eastern Haratghe Oromia National Regional State Ethiopia. International Journal of Development

and Economic Sustainability, 1(1), pp.15-30.

[31] Homann S, van Rooyen A, Moyo T and Nengomasha Z. 2007. Goat production and marketing: Baseline information for semi-arid Zimbabwe. PO Box 776, Bulawayo, Zimbabwe: International Crops Research Institute for the Semi-Arid Tropics. 84 pp.

[32] Mawazo, M., Kisangiri, M., and Jeseku K., (2014). Access to agricultural market information by rural farmers in Tanzania. Vol 4 No 7

[33] Pienaar L and Traub L.N., (2015). Understanding the smallholder farmer in South Africa: Towards a sustainable livelihoods classification .International conference of agricultural economics, Milan, Italy.

## *Edited by Sándor Kukovics*

This volume provides a comprehensive overview of goat keeping and farming. It includes twenty-two chapters that address such topics as breeding and selection, goat reproduction, production systems, the effects of goat farming on the environment, the use of goat byproducts, the economics of goat farming, and much more.

Published in London, UK © 2023 IntechOpen © Jannick Tessier / iStock

Goat Science - Environment, Health and Economy

Goat Science

Environment, Health and Economy

*Edited by Sándor Kukovics*


3. Boundary and initial condition

When the ballistic transport appear the temperature jump at boundary occur and cause the reduction of the thermal conductivity [27, 32]. Ben Aissa et al. [12] have been explored a nanoheat conduction in cylindrical surrounding-gate (SG) MOSFET. They used the DPL with the temperature jump applied in the interface oxide-semiconductor defined as

$$
\Delta T\_{jump} = -d \times \text{Kn} \times L \times \nabla T \tag{22}
$$

where d is an adjustable coefficient, the ETC defined as [12]:

$$d = \frac{R \times \kappa\_{\text{eff}}}{Kn \times L\_c} \tag{23}$$

where R is the thermal boundary resistance. The proposed ETC given by Ben Aissa et al. [12, 32] is written as:

$$\kappa\_{\sharp\sharp} = \kappa / (1 + (4 \times \text{Kn})) \tag{24}$$

Hua et al. [33, 34] discussed the temperature jump in nanofilms. They have studied the phonon transport in interfaces. They derived a boundary temperature jump defined as

Table 1. First-order temperature jump condition.

$$T - T\_W = -d \times \Lambda \times \frac{\partial T}{\partial \mathbf{x}} \tag{25}$$

where TW is the temperature jump at the wall.

Yang et al. [35] explained the impact of the temperature jump in the continuum flow and slip flow. They have investigated the heat transfer in nanofluids. At the wall, the temperature jump lead to the following expression by Gad-el-Hak [35]

$$T\_S - T\_W = \frac{2\beta}{\beta + 1} \frac{2 - \sigma\_T}{\sigma\_T} \frac{\Lambda}{\Pr} \frac{dT}{dy} \bigg|\_{\text{wall}} \tag{26}$$

where TS is the system temperature and TW is the wall temperature, σT is the thermal accommodation coefficient, β is the ratio of specific heats, and Pr is the gas Prandtl number. Singh et al. [36] noted that in ideal monoatomic gas (Kn < 0:1), the temperature jump at the solid interface rewritten as

$$T\_S - T\_W = \frac{1.25 \times \Lambda}{\text{Pr}} \frac{dT}{dy} \bigg|\_{\text{Wall}} \tag{27}$$

To solve the BDE model coupled with the temperature jump at boundary we use the FEM [4].

Si 3000 150 1.5 � 106 100 10 SiO2 5900 1.4 1.75 � 106 0.4 0.04

) C (J m�3 k�1

where ½ � B , ½ � B1 and ½ � D is a matrix valued, f g Tt , f g Ttt and f gT represent the nodal temperature,

þ 2 ½ � B Δt 2 þ ½ � D

The materials used in our simulation are Silicon [2] and Silicon dioxide [2] and their thermal

The reduction of the thermal conductivity have a strong dependence with the Knudsen number. We take account the specularity parameter and Knudsen number because we studied the

is the nodal temperature at the time tp.

½ � B f g Tt þ ½ � B1 f g Ttt � ½ � D f gT ¼ f g m (28)

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� Tp�1 ½ � B

Δt 2

þ f g m p (29)

) Λ (nm) Kn

The finite-element approximation used in the BDE model can be defined as:

) K (Wm�1 K�1

f g m is the matrix vector.

Symbol V (m s�1

The discretization of Eq. (25) leads to

Δt

Figure 1. Schematic geometries of the MOSFET transistor.

Table 2. Thermal properties of Silicon and Silicon dioxide.

þ ½ � B Δt 2 ¼ Tp ½ � B Δt

Tpþ1 ½ � B

where Δt is the time step and Tp

properties are illustrated in Table 2.

5. Results and discussion

mechanism of boundary scattering.

Due to the utility of the temperature jump, the following expressions are summarized in Table 1.

## 4. Structure to model and numerical method

The architecture used in this present work is the two-dimensional conventional MOSFET. The proposed structure shown in Figure 1. The substrate is compound by Silicon (Si). The Si-MOSFETs thickness used in this model is 50 nm. The channel length is Lc = 10 nm. In order to compare our results with similar works, the reference temperature is T0 = 300 K and the maximal power generation is q\_ h ¼ 1019w=m3 [23]. The right and left boundaries are assumed to be adiabatic. The temperature jump boundary condition is applied in the interface (Si-SiO2). In this side the phenomena of collision phonon-wall is more frequent. The MFP used in this proposed work is Λ ¼ 100 nm [23]. Using Eq. (17), we found that the thermal conductivity reaches 18 Wm�1 k�1 . In this case, the adjustable coefficient d attains 0.09 for R = 0.503 K m2 W�1 [37].

Study of Heat Dissipation Mechanism in Nanoscale MOSFETs Using BDE Model http://dx.doi.org/10.5772/intechopen.75595 21

Figure 1. Schematic geometries of the MOSFET transistor.

T � TW ¼ �d � Λ �

Yang et al. [35] explained the impact of the temperature jump in the continuum flow and slip flow. They have investigated the heat transfer in nanofluids. At the wall, the temperature jump

> 2 � σT σT

Λ Pr dT dy Wall

dT dy Wall

h ¼ 1019w=m3 [23]. The right and left boundaries are assumed

β þ 1

TS � TW ¼ 1:25 � Λ

where TS is the system temperature and TW is the wall temperature, σT is the thermal accommodation coefficient, β is the ratio of specific heats, and Pr is the gas Prandtl number. Singh et al. [36] noted that in ideal monoatomic gas (Kn < 0:1), the temperature jump at the solid

Pr

Due to the utility of the temperature jump, the following expressions are summarized in

The architecture used in this present work is the two-dimensional conventional MOSFET. The proposed structure shown in Figure 1. The substrate is compound by Silicon (Si). The Si-MOSFETs thickness used in this model is 50 nm. The channel length is Lc = 10 nm. In order to compare our results with similar works, the reference temperature is T0 = 300 K and the

to be adiabatic. The temperature jump boundary condition is applied in the interface (Si-SiO2). In this side the phenomena of collision phonon-wall is more frequent. The MFP used in this proposed work is Λ ¼ 100 nm [23]. Using Eq. (17), we found that the thermal conductivity reaches 18

. In this case, the adjustable coefficient d attains 0.09 for R = 0.503 K m2 W�1 [37].

TS � TW ¼ 2β

Pr For Kn < 0:1

where TW is the temperature jump at the wall.

Present work 0.09 For Kn ¼ 10

interface rewritten as

maximal power generation is q\_

Table 1.

Wm�1 k�1

lead to the following expression by Gad-el-Hak [35]

Work Adjustable coefficient d Ben Aissa et al. [12] 0.05 For Kn ¼ 3:33 Hua and Cao [33] 0.66 For Kn < 5

Sing et al. [36] 1:25

20 Green Electronics

Table 1. First-order temperature jump condition.

4. Structure to model and numerical method

∂T

∂x (25)

(26)

(27)

Table 2. Thermal properties of Silicon and Silicon dioxide.

To solve the BDE model coupled with the temperature jump at boundary we use the FEM [4]. The finite-element approximation used in the BDE model can be defined as:

$$[B]\{T\_t\} + [B\_1]\{T\_H\} - [D]\{T\} = \{m\} \tag{28}$$

where ½ � B , ½ � B1 and ½ � D is a matrix valued, f g Tt , f g Ttt and f gT represent the nodal temperature, f g m is the matrix vector.

The discretization of Eq. (25) leads to

$$\left\{{T\_{p+1}\}\left(\frac{[\mathcal{B}]}{\Delta t} + \frac{[\mathcal{B}]}{\Delta t^2}\right) = \left\{{T\_p\}\left(\frac{[\mathcal{B}]}{\Delta t} + 2\frac{[\mathcal{B}]}{\Delta t^2} + [\mathcal{D}]\right) - \left\{{T\_{p-1}}\right\}\left(\frac{[\mathcal{B}]}{\Delta t^2}\right) + \{m\}\_p\right\} \tag{29}$$

where Δt is the time step and Tp is the nodal temperature at the time tp.

The materials used in our simulation are Silicon [2] and Silicon dioxide [2] and their thermal properties are illustrated in Table 2.

### 5. Results and discussion

The reduction of the thermal conductivity have a strong dependence with the Knudsen number. We take account the specularity parameter and Knudsen number because we studied the mechanism of boundary scattering.

Figure 2. Effective thermal conductivity vs. Knudsen number.

In Figure 2 we shows the impact of the thermal conductivity which depend on the specularity parameter. In this case, we use Eq. (17) to inquire the ETC. It is obvious that the thermal conductivity reduce when the Knudsen number increase. In similarity to the analytical model proposed by Hua and Cao et al. [32], it is found that the thermal conductivity reaches 62% of the bulk value for Kn = 1.

Figure 3 plot the ETC for various the length of nanofilms. For low thin films (L = 10 nm) the thermal conductivity attains 10–20% of the bulk value. The ballistic transport involve the rapid increase of the ETC. For p = 0.25 we shows the same shape obtained by Ma [29]. For thin films (L > 1000 nm), p = 0.25 is a good approximation.

The advantage of our proposed model is the capture of the increase of the temperature better than the other transport model (DPL, SPL and classical BDE). We associated the BDE model with the temperature jump. The obtained results are presented along the centerline (Lx/2, Y = 0) at the time t = 30 ps. In the ballistic regime (Kn = 10) we use Eq. (18). For high Knudsen number the heat transport influenced by the mechanism of scattering related to the boundary. This type of collision was examined by Guo et al. [38] they deduced a discrete-ordinate-method (DOM) derived by the Callaway's model [38]. They found acceptable results to determinate the ETC in a rectangular graphene ribbon. The Callaway's model based on a simple boundary scattering.

Figure 4 illustrate the comparison of the peak temperature rise in the nano-transistor at t = 30 ps. The classical BDE, BTE, DPL, SPL, Fourier law and our proposed model reaches respectively 318.7, 327, 320.5, 318.9, 305 and 322.7 K. The new BDE model capture the increase of the temperature near the BTE. For low thin-film (Lc = 10 nm) one can see that the temperature attaints the maximal at short time. The saturation of the temperature varied to 12–15 ps for all model transport. The classical Fourier law cannot predict the temperature profile due the nature of phonon thermal transport [39].

The temperature peak rise in the Y-direction at the centerline of the nanodevice is demonstrated in Figure 5. The decrease of the temperature is owned to the reduction of the thermal conductivity. Our present model has the same form with the classical BDE model. The difference appear in low temperature due to the collision rate, which depend on the specularity.

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Figure 4. Comparison of the peak temperature at the centerline.

Figure 3. Effective thermal conductivity in Silicon thin film at room temperature.

Figure 6 illustrate the 2D distribution of the temperature at t = 30 ps. In a short time, the temperature increase in the left and right side of the channel region. This side known as the heat zone of the nanodevice. A self-heating processes appear due to nature of the phonon Study of Heat Dissipation Mechanism in Nanoscale MOSFETs Using BDE Model http://dx.doi.org/10.5772/intechopen.75595 23

Figure 3. Effective thermal conductivity in Silicon thin film at room temperature.

In Figure 2 we shows the impact of the thermal conductivity which depend on the specularity parameter. In this case, we use Eq. (17) to inquire the ETC. It is obvious that the thermal conductivity reduce when the Knudsen number increase. In similarity to the analytical model proposed by Hua and Cao et al. [32], it is found that the thermal conductivity reaches 62% of

Figure 3 plot the ETC for various the length of nanofilms. For low thin films (L = 10 nm) the thermal conductivity attains 10–20% of the bulk value. The ballistic transport involve the rapid increase of the ETC. For p = 0.25 we shows the same shape obtained by Ma [29]. For thin films

The advantage of our proposed model is the capture of the increase of the temperature better than the other transport model (DPL, SPL and classical BDE). We associated the BDE model with the temperature jump. The obtained results are presented along the centerline (Lx/2, Y = 0) at the time t = 30 ps. In the ballistic regime (Kn = 10) we use Eq. (18). For high Knudsen number the heat transport influenced by the mechanism of scattering related to the boundary. This type of collision was examined by Guo et al. [38] they deduced a discrete-ordinate-method (DOM) derived by the Callaway's model [38]. They found acceptable results to determinate the ETC in a rectangular graphene ribbon. The Callaway's model based on a simple boundary scattering. Figure 4 illustrate the comparison of the peak temperature rise in the nano-transistor at t = 30 ps. The classical BDE, BTE, DPL, SPL, Fourier law and our proposed model reaches respectively 318.7, 327, 320.5, 318.9, 305 and 322.7 K. The new BDE model capture the increase of the temperature near the BTE. For low thin-film (Lc = 10 nm) one can see that the temperature attaints the maximal at short time. The saturation of the temperature varied to 12–15 ps for all model transport. The classical Fourier law cannot predict the temperature profile due the

the bulk value for Kn = 1.

22 Green Electronics

(L > 1000 nm), p = 0.25 is a good approximation.

Figure 2. Effective thermal conductivity vs. Knudsen number.

nature of phonon thermal transport [39].

Figure 4. Comparison of the peak temperature at the centerline.

The temperature peak rise in the Y-direction at the centerline of the nanodevice is demonstrated in Figure 5. The decrease of the temperature is owned to the reduction of the thermal conductivity. Our present model has the same form with the classical BDE model. The difference appear in low temperature due to the collision rate, which depend on the specularity.

Figure 6 illustrate the 2D distribution of the temperature at t = 30 ps. In a short time, the temperature increase in the left and right side of the channel region. This side known as the heat zone of the nanodevice. A self-heating processes appear due to nature of the phonon

Figure 5. Peak temperature rise versus Y-axis at the centerline of the MOSFET at t = 10 ps.

collision which is characterized by a frequent scattering at boundary. The augmentation of the temperature cause an important dissipation of energy, which affect the environment. In the last years, organic electronic was made to reduce the energy consumption and the thermal resis-

Study of Heat Dissipation Mechanism in Nanoscale MOSFETs Using BDE Model

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Figure 7 shows the comparison of the heat flux in the Y-direction at the centerline of nano-MOSFET. Using the BDE model for p = 0.18, we obtain the same shape and amplitude given by the BTE. The temperature jump at boundary is a good argument to predict the non-Fourier heat transfer [41]. The increase of the heat flux is caused by two raison: the reduction of the thermal conductivity and the length of nanostructure. To reduce the heat dissipation in nanoelectronic materials, it is necessary that the current densities was minimized [9]. A preferment devise is characterized by minimal power consumption. In a technological concept, the graphene is an excellent material which described by high thermal conductivity and low

In this chapter, we report a nano-heat conduction based on the BDE model. The temperature jump is good proof to study the thermal properties of nano-materials. Our proposed model is efficient approach for the non-Fourier heat conduction. In addition, our obtained results agree with other transport model. In nanostructure the reduction of the thermal conductivity and phonon collision mechanism. Our study explain the distribution of the temperature in 10 nm

tance between materials [40].

Figure 7. Comparison of the heat flux in the Y direction at t = 10 ps.

temperature rise [25, 42].

6. Conclusions

Figure 6. A 2D temperature distribution for p = 0.18 at t =30 ps.

Figure 7. Comparison of the heat flux in the Y direction at t = 10 ps.

collision which is characterized by a frequent scattering at boundary. The augmentation of the temperature cause an important dissipation of energy, which affect the environment. In the last years, organic electronic was made to reduce the energy consumption and the thermal resistance between materials [40].

Figure 7 shows the comparison of the heat flux in the Y-direction at the centerline of nano-MOSFET. Using the BDE model for p = 0.18, we obtain the same shape and amplitude given by the BTE. The temperature jump at boundary is a good argument to predict the non-Fourier heat transfer [41]. The increase of the heat flux is caused by two raison: the reduction of the thermal conductivity and the length of nanostructure. To reduce the heat dissipation in nanoelectronic materials, it is necessary that the current densities was minimized [9]. A preferment devise is characterized by minimal power consumption. In a technological concept, the graphene is an excellent material which described by high thermal conductivity and low temperature rise [25, 42].

### 6. Conclusions

Figure 5. Peak temperature rise versus Y-axis at the centerline of the MOSFET at t = 10 ps.

24 Green Electronics

Figure 6. A 2D temperature distribution for p = 0.18 at t =30 ps.

In this chapter, we report a nano-heat conduction based on the BDE model. The temperature jump is good proof to study the thermal properties of nano-materials. Our proposed model is efficient approach for the non-Fourier heat conduction. In addition, our obtained results agree with other transport model. In nanostructure the reduction of the thermal conductivity and phonon collision mechanism. Our study explain the distribution of the temperature in 10 nm MOSFET. The maximal temperature is located in the interface oxide-semiconductor. To reduce the effect of the thermal transport in nano-electronic materials it is obvious that we should replace Si based materials by organic technologies (carbon based). Green electronics are involved in recent integrated circuits, solar cell and high-speed processors. In addition, green materials has a wide biocompatibility and a safe impact on the environment [43].

[9] Nasri F, Echouchene F, Ben Aissa MF, Graur I, Belmabrouk H. Investigation of Self-heating effects in a 10-nm SOI-MOSFET with an insulator region using electrothermal modeling. IEEE (Institute of Electrical and Electronics Engineers) Transaction on Electron Devices.

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[10] Nasri F, Ben Aissa MF, Belmabrouk H. Nanoheat conduction performance of black phosphorus filed-effect transistor. IEEE (Institute of Electrical and Electronics Engineers) Trans-

[11] Nasri F, Ben Aissa MF, Belmabrouk H. Nonlinear electrothermal model for investigation of heat transfer process in a 22-nm FD-SOI MOSFET. IEEE (Institute of Electrical and

[12] Ben Aissa MF, Nasri F, Belmabrouk H. Multidimensional nano heat conduction in cylindrical transistors. IEEE (Institute of Electrical and Electronics Engineers) Transaction on

[13] Wang HD, Cao BY, Guo ZY. Heat flow in carbon nanotubes. International Journal of Heat

[14] Alvarez FX, Jou D. Memory and nonlocal effects in heat transport: From diffusive to

[15] Tzou DY. Macro-to Microscale Heat Transfer: The Lagging Behavior. Chichester: John

[16] Alvarez FX, Jou D, Sellitto A. Phonon hydrodynamics and phonon-boundary scattering in

[17] Jou D, Criado-Sancho M, Casas-Vázquez J. Heat fluctuations and phonon hydrodynamics

[18] Guo Y, Wang M. Phonon hydrodynamics for nanoscale heat transport at ordinary tem-

[19] Sellito A, Carlomango I, Jou D. Two-dimensional phonon hydrodynamics in narrow

[20] Chen G. Ballistic-diffusive heat-conduction equations. Physical Review Letters. 2001;86:

[21] Chen G. Ballistic-diffusive equations for transient heat conduction from nano to macroscales. ASME (The American Society of Mechanical Engineers) Journal Heat Transfer.

[22] Hamian S, Yamada T, Faghri M, Park K. Finite element analysis of transient ballisticdiffusive phonon heat transport in two-dimensional domains. International Journal of

[23] Yang R, Chen G, Laroche M, Taur Y. Simulation of nanoscale multidimensional transient heat conduction problems using ballistic-diffusive equations and phonon Boltzmann

Electronics Engineers) Transaction on Electron Devices. 2017;4:1461-1466

2015;62:2410-2415

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ballistic regimes. Applied Physics Letters. 2007;90:083109

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2002;124:320-328. DOI: 10.115/1.1447938

Heat and Mass Transfer. 2015;80:781-788


**8. Future Research**

Many shortcomings in the current practice for river relocations have been highlighted in high-profile failures, such as the Morwell River collapse in Victoria, Australia, or in poor attainment of rehabilitation objectives. White et al. [70,72] highlight the need to revise most current river relocation designs to reduce subsequent impacts to adjacent waterways.

The regional characteristics of natural rivers should be considered during the design of new relocated channels [102]. This is particularly true in the rivers demonstrating behaviour that do not fit the planform or criteria found in European and North American rivers. Greater distinction between perennial and ephemeral watercourses is needed to fully understand the mechanisms that control major channel adjustment, such as flash flooding [81,91]. This is particularly relevant where mining operations are located in arid areas with unusual geomorphology and hydrology. The recovery of vegetation in diverted channels should also be a specific area of research.

Globally, the majority of literature surrounding river relocation is derived from grey literature, or environmental impact assessments, with minimal long-term assessment or evaluation of these projects. Our ability to construct an artificial natural channel is a measure of our understanding of natural channels, which can be limited by poor understanding of various river planforms, such as the anabranching channel, or relocated channels constructed in settings that do not fit European or North American perennial rivers. As such, river relocation channels can be considered as large-scale geomorphic experiments. Within Australia, the ACARP guidelines provide criteria for river relocation designs with explicit consideration of stream type and geomorphology, proving hydraulic reference values for future relocation channel designs. However, these values are best suited to Queensland, with other states and territories lacking equivalent criteria.

Concern about environmental values of river relocations are still emerging. Relocation channels were previously constructed to transfer water from one area to another, with limited concern for the river's natural values. Now, river relocation channels are planned with a consideration of regional planforms and characteristics of the natural channel, including the high interannual flow variability of Australian rivers [105].


**Abstract**

Optical fiber tweezers, as a versatile tool for optical trapping and manipulation, have attracted much attention in cell trapping, manipulation, and detection. Particularly, assembly of living cells using optical fiber tweezes has become a significant attention. Advanced achievements have been made on the assembly of fully biocompatible photonic probes with biological cells, enabling optical detection in biological environment in a highly compatible manner. Therefore, in this chapter, we discuss the use of optical fiber tweezers for assembly of living photonic probes. Living photonic probes can be assembled by the trapping and assembly of multiple cells using optical fiber tweezers. These photonic probes exhibit high biocompatibility and show great promise for the bio-applications in bio-microenvironments.

**Keywords:** Optical fiber tweezers, living photonic probes, optical trapping, optical manipulation, cell assembly

## **1. Introduction**

The development of optical fiber tweezers (OFTs) makes it a versatile candidate for optical trapping and manipulation of targets ranging from different dielectric particles to biological cells and biomolecules [1–3]. This is because OFTs possess exceptional advantages in manipulation flexibility, due to the simple structure with only optical fibers. This simple structure also avoids the use of a high numericalaperture objective which is necessary for the light focusing in conventional optical tweezers system [4, 5]. It is much easier to handle and manipulate the microscopic objects after trapped with OFTs [6, 7]. And it is much more suitable for practical use such as in trapping, levitating and rotating of microscopic particles in different environments [8–10]. The OFTs tip can be inserted into thick samples and turbid media, which greatly increases the sample applicability. In addition, OFTs exhibit a low-cost manipulation technique and can also be integrated into small devices, such as optofluidic channels [11]. OFTs enable the trapping and manipulation of different single targets. For the further biological detection in bio-environments, it is highly desired to form biocompatible photonic probes that can minimize the physical damage to the biological samples. Unfortunately, most photonic probes are made from inorganic and artificial materials, which are incompatible and invasive when interfacing with biological systems. It is still a big challenge to find out a biomaterial to assemble biophotonic probes that are noninvasive and highly biocompatible to

biological systems. Fortunately, it is found that living cells, which are abundant in the natural world, show the capability for light manipulation and propagation with high biocompatibility, and can thus be used for the assembly of living photonic probes. In this chapter, recent advances of OFTs in trapping and manipulating of cells, particularly in assembly of living photonic probes based on biological cells, were discussed. These formed living photonic probes provide a promising approach for bio-detection in biological environments with highly biocompatibility [12, 13].


**Preface to "Synthetic Biology Brings New Opportunity for Antibiotics Discovery"**

Though society is developing much more rapidly today than it did in the past, we are facing a complicated public health issue in the form of global drug shortages, and antimicrobials are unfortunately on that list. These shortages are caused by various issues, e.g., technological limitations, which have led to a drying up of the pipeline of antimicrobial development. Indeed, it has been decades since antibiotics with a completely novel mode of action were last delivered to the clinic. The limited availability of antibiotics, in addition to the rapid emergence of multidrug resistance, are putting us in a very dangerous position. Luckily, the advances of new technologies, especially biotechnologies, such as DNA sequencing, precise genome editing, system metabolic engineering, multiomics, synthetic biology, big data processing, and artificial intelligence are offering a great opportunity to develop better and efficient bioactive molecules, including next-generation antibiotics. Currently, various achievements and new discoveries from both academia and industry are taking place in the broad field of antibiotics, which reflects the fact that a new era is coming. As one of the most important driving forces, academia plays a critical role in drug discovery for a safer society, and, thus, we would like to bring academia, industry, and clinic together in this Special Issue to report recent progress in antibiotics discovery.


**2. Some history**

The possibility of gravitational waves was discussed in 1893 by Oliver Heaviside using the analogy between the inverse square law of distance in gravitation and electricity [7]. In 1905, Henri Poincaré proposed for the first time the existence of gravitational waves, which emanated from accelerated bodies and propagated at the same speed of light, this is dictated by the transformations of Lorentz [8] and implies an analogy that, accelerating electric charges produce electromagnetic waves, accelerating masses must emanate gravitational waves. When publishing his theory of gravitation (the general theory of relativity) in 1915, Einstein did not agree with Poincaré's proposal, as in his theory there are not gravitational dipoles, essential for the emission in the electromagnetism theory. However, based on a weak field approximation, he concluded that there should be three kinds of gravitational waves (named by Hermann Weyl as longitudinally-longitudinally, transversely-longitudinally, and transversely-transverse).

These approximations made by Einstein were criticized by several researchers and even Einstein had doubts. In 1922, Arthur Eddington wrote a paper entitled: "The propagation of gravitational waves" [8], in which he showed that two of the three types of waves proposed by Einstein were only mathematical artifacts produced by the system of coordinates and they were not really waves. This also cast doubt on the physicality of the third type (transversely transverse); however, Eddington proved that these would travel at the speed of light in all coordinate systems, so he did not rule out their existence.

In 1956, Felix Pirani corrected the confusion caused by the use of several coordinate systems by reformulating gravitational waves as the manifestation of the Riemann tensor observables. The Pirani work was ignored at that time mainly because the scientific community was concerned with another issue of whether gravitational waves could transport energy. This question was solved by Richard Feynman using a thought experiment presented at the first conference for General Relativity in 1957 known as the Chapel Hill Conference. His argument, known as the sticky bead argument, presents that: if a gravitational wave passes orthogonally to the beaded rod (a rod if some bead), the effect of it is to deform the bead and the rod, but as the rod is longer, the bead moves beads over the rod; this movement causes friction and then heat, which meant the passing gravitational wave would have energy. Afterward,

#### *Interferometric Gravitational Wave Detectors DOI: http://dx.doi.org/10.5772/intechopen.106417*

Hermann Bondi (who was skeptical of the existence of gravitational waves) published a more complete version of this argument.

After this conference, the scientific community took the existence of gravitational waves more seriously. Joseph Weber began to design and build a gravitational wave detector. It was the start of many gravitational wave detectors that are called Weber bars. Weber claimed to have detected gravitational waves in 1969 and 1970, the signals coming from the Galactic Center [9]. However, the high detection frequency quickly cast doubt on the validity of his observations, as the Milky Way's implied rate of energy loss would drain our galaxy's energy on a much shorter timescale than the galaxy's inferred age. It got worse when in the middle of the 1970 decade, the build of other Weber bar experiments by other groups around the world failed to detect such signs. By the end of the 1970 decade, the consensus was that Weber's detections were some kinds of noise.

The first indirect evidence of gravitational waves was discovered in 1974 by Russell Alan Hulse and Joseph Hooton Taylor Jr., using their discovery of the first binary pulsar. Results were published in 1979, showing the measure of the orbital period decay of the, so-called, Hulse-Taylor pulsar, which precisely describes the angular momentum and energy loss due to gravitational radiation emission predicted by general relativity. A discovery that gave them the 1993 Physics Nobel Prize.

This indirect detection of gravitational waves motivated further searches, despite Weber's discredited result. Some groups continued to improve on Weber's original concept. Using very low temperatures (cryogenic) for the bars, in high-vacuum systems and under vibrational isolation. There were many of these projects around the World. One of these groups built a Niobium bar resonant-mass gravitational wave detector [10]. In this detector, the vibrations caused by the passage of gravitational waves in the niobium bar are measured by a microwave parametric transducer. In this system, microwaves are pumped into a microwave cavity and the vibrations of the microwave cavity are connected to the niobium bar causing microwave signals in the microwaves to leave the cavity. This signal now must be amplified, but it mixes with the original microwave signal, which is too strong for the low-noise microwave amplifier; then the microwave carrier signal is removed by the use of an interferometer that cancels only the microwave carrier. A similar system can be seen in **Figure 1**. This is another use for interferometers in gravitational wave detectors; unfortunately, this kind of detector never made a detection, maybe because of a poor choice in the frequency range [11].

Other experimental groups pursued gravitational wave detection using laser interferometers. This idea of using appears to have been around for a long time by several independent groups, for example in 1962 ME Gertsenshtein and VI Pustovoit [12] and in 1966 by the group of Vladimir B. Braginskiĭ. The first prototype appeared in the 1970 decade built by Robert L. Forward and Rainer Weiss. In the following decades, increasingly sensitive detectors were constructed, culminating in LIGO and Virgo detectors.

After years and years of null results, the first detection of gravitational waves was made by LIGO on September 14, 2015, as the signal, named GW150914, probably came from the merger of two black holes [13, 14]. A year earlier, LIGO could have been brought down when scientists from the BICEP2 (Background Imaging of Cosmic Extragalactic Polarization 2) experiment claimed to have detected a weak signal in the CMB (Cosmic Microwave Background) that appeared like evidence of gravitational waves originating in the beginning universe. This evidence, according to researchers, could have been a smoking gun proof of the theory of cosmic inflation, which

#### **Figure 1.**

*Schematics of a similar electronics of Niobè gravitational wave detector showing a microwave interferometer (between the cryogenic circulator and the cryogenic low-noise amplifier) used to cancel the microwave carrier signal that will degrade the performance of the cryogenic low-noise amplifier.*

postulates that very shortly after the Big Bang (10−32 seconds after), the expanding universe experienced a period of very rapid expansion (a factor of 1026 times). This fast expansion would have created ripples over the CMB, the fossil cosmic radiation that fills the universe being the first detectable electromagnetic radiation in Universe history. However, the BICEP2 signal detected could be explained also by Milky Way dust, making the scientists withdraw the claim that gravitational waves had been detected.


*3.2.3 From peasant agriculture to wheat-barley monocultures fourteenth and twentieth centuries*

Prior to the arrival of the Hispanic occupation, the most characteristic indigenous peoples of the high equatorial mountains were the various peoples of the Cauca River, the Patía and the Putumayo, the Quimbaya peoples of the Central Mountain Range, the Pijao people in Tolima, the great Muisca people in the Cundiboyacense highlands and the Arawak peoples. Tairona, kogi, arsarios, and others in the Sierra Nevada de Santa Marta.

From these peoples and their miscegenation with the Hispanic element, a mestizo peasant people emerged that today characterizes the majority of the Colombian population in the highlands.

From the sixteenth century with the Hispanic occupation, cereal crops such as wheat and barley and deciduous fruit trees were introduced, which displaced, either by intensity or by express prohibition of the Spanish crown to indigenous crops. Cattle and sheep also entered, which became an element of high importance for peasant life, due to its milk, meat and wool products, the latter replacing cotton in blankets throughout the highlands of Cundiboyacense and Santander mainly. In this way what brought the Hispanic invasion to the Colombian Andean zone was not its culture but its Mediterranean nature forged by long centuries of Roman, Mongolic and Arab occupation.

Throughout the period from the sixteenth century until the first half of the twentieth century, the occupation of these peoples was made in the areas of the equatorial forests of high mountain. During the Colony, it was these forests that provided wood inputs for the nascent and flourishing peoples during this period and the first phase of the birth of the Republic between the nineteenth and twentieth centuries. The occupation of species such as oak encenillo, tuno, cucharo el cedar, and guayacán stands out.

Peasant agriculture in these high mountain areas was characterized by crop rotation between corn, potatoes, quinoa, and legumes typical of the area and others brought from the old continent such as barley, wheat, and oats.

In particular, these last two crops formed the basis of peasant economies that provided for a long period of inputs for bread and beverages in urban areas of towns and cities. Whole wheat bread, soups of various varieties of wheat and barley were staples of families in the cold lands and especially in cities such as Bogotá, Tunja, and Popayán. The peasant arepa based on corn and its multiple forms of preparation is today one of the staple foods of the Colombian population.

#### **3.3 Industrialization of the countryside and extractivism**

#### *3.3.1 Industrial potato monoculture and its impact on high Andean ecosystems*

Since pre-Hispanic times, the peoples of the highlands of the Andes and the Sierra Nevada de Santa Marta cultivated potatoes as one of their most precious products along with corn and arracacha. Until the early twentieth century in Boyacá, various varieties of wild potatoes were collected, which were born spontaneously in the clearings of the high Andean forests. Due to the population growth of urban areas after the 1950s, the demand for this tuber grew and with it research on new varieties. Prior to the Green Revolution that emerged strongly in the 1960s, potato crops were fertilized with organic materials resulting from the composting of livestock and poultry manure, as well as ash from the burning of firewood as fuel in peasant homes. At this time, potato crops were made in the area of Andean forests up to 3000 m above sea level. The introduction of new varieties of potato dependent on agrochemicals for fertilization and control of pests and diseases, generated during the Green Revolution, was propitiating the occupation of moors and areas of high Andean forest, encouraging the monopolization of land in fewer and fewer smallholder owners or tenants of peasant plots, which altered the mosaic of high Andean mountain ecosystems where the main victim was the forest. In this way, the large forest masses have been disappearing at the expense of the agricultural frontier for potato planting with rotation with semi-extensive livestock that today characterizes much of the territory. During the 1990s, especially in the Central mountain range, poppy crops proliferated in these areas. One of the great socio-environmental problems of today is the uncontrollable growth of industrial potato crops, with high consumption of biocides that affect the recharge areas and birth of water resources of thousands of streams and hundreds of rivers. During this process, the peasant went from small smallholder with his plot of multi-stratum crops to day laborer in potato crops and cattle farms in these mountainous regions.


**4. Conclusion**

The study region receives an average annual rainfall of less than 300 mm, which explains it's belonging to the arid bioclimatic stage of climate. Precipitation has experienced a very marked interannual irregularity in recent years. The thermal amplitudes were lead to a much faster dieback of annual plants, subjected to intense evapotranspiration.

Climatic data from stations in the study region allowed us to observe the spatiotemporal evolution on a North–South gradient that depends on the irreversible phenomena such as aridity, evaporation (drying out of soils).

This work analyzes the variability of evapotranspiration for steppe vegetation. It is based on climate data measured at three meteorological stations in Naama region. The calculation of evapotranspiration by the water balance method, gave rather satisfactory results insofar as these results oscillate around the normal values of evapotranspiration for the three stations in the study region. Potential evapotranspiration (ETP) data estimated from Thornthwaite's method for the three stations (Mécheria, Naâma and Ain Sefra). The annual average value of potential evapotranspiration is of the order of 807 mm in Mécheria, 795 mm in Naâma de and Ain sefra at 847 mm. It is clearly 3 to 4 times higher than the value of the rainfall received. For this purpose, the PET generates a water deficit (drought) and/or favors a considerable influence on the soil and the growth of vegetation in the steppe ranges. In this steppe area of Naâma, the average annual precipitation is less than two thirds of the potential evapotranspiration (potential evaporation from the *Biophysical Effects of Evapotranspiration on Steppe Areas: A Case Study in Naâma… DOI: http://dx.doi.org/10.5772/intechopen.97614*

ground plus transpiration by plants). The high evapotranspiration confirm the climate aridity of the study area.

The vegetation can have an impact on the water balance by increasing evapotranspiration and reducing runoff, and the vegetation is characterized by various morphological, physiological adaptations such as xerophytes.

It is therefore easy to understand why most steppe species have low woody and herbaceous plants, and they have characteristics of xeropmorphism (*Stipa tenacissima, Lygeum spartum, Stipagrostis pungens*)) and sclerophyllia, especially in phanerophytes (*Quecus ilex, Pinus halepensis, Juniperus phoenicea, Juniperus oxycedrus, Pistacia atlantica*). They have as a result low size of plants and leaves, and low gross production. These plants reduce their exchange surfaces and close their stomata.

In perspective, it is necessary to assess this component of the water balance precisely from field measurements and to establish maps taking into account the particularities of the existing vegetation. This type of study makes it possible to formulate recommendations to better understand the species adapted to these climatic rigors.


**2. Erythrocytes and hemoglobin in teleost in the norm and under toxic effects**

#### **2.1 Erythrocytes and hemoglobin in teleost in the norm**

The erythrocytes of teleost fishes have a similar morphology to the erythrocytes of other non-mammalian vertebrates. They are nucleated cells with an elliptical to oval shape. Their cytoplasm is eosinophilic, and the nucleus is centrally located, deeply basophilic, with an oval to elliptical shape. Erythrocyte sizes range from 102 to 800 fl [3, 4]. Moderate anisocytosis and polychromasia are normal in teleost species.

Their life span is 13–500 days. The number of erythrocytes in the peripheral blood depends on many factors—fish activity, water temperature, and dissolved oxygen concentration, as well as other environmental factors and shows significant seasonal variability. Furthermore, it depends on age, sex, nutritional and reproductive status, and may differ between populations of the same species. It typically ranges from 0.5–1.5 × 106 /mm3 in less active species to 3.0–4.2 × 106 /mm3 in more active species. Antarctic icefishes, adapted to cold and well-oxygenated water, do not have erythrocytes.

The main erythropoietic organ in teleost is the head kidney. Erythropoiesis is similar to that of other vertebrates and involves the same precursors. Characteristically, in teleost fishes, the barrier between the hematopoietic tissue and the circulatory system is weak, and therefore in the circulating blood, many immature red blood cells are found, often constituting more than 10% of all erythrocytes. Immature erythrocytes are round rather than oval in shape, their cytoplasm is blue-stained, and their nucleus is larger and heterochromatic.

As in other vertebrates, fish erythrocytes contain tetrameric hemoglobins, but with different oxygen affinities. It is lower in species living in well-oxygenated water than in those exposed to hypoxia. Several hemoglobin isoforms with different oxygen affinities are often present in the blood of fish, which is considered an adaptation to variable oxygen concentration in the water. Fish erythrocytes are sensitive to environmental pollution, and their morphological assessment can be used as a bioindicator of toxicity [3].

#### **2.2 Hematological disorders in teleost as a biomarker for water pollution**

Hematologic studies in fish have been performed for more than 70 years now. Recently, they have gained great importance because they are an effective and sensitive indicator for evaluating physiological and pathological changes caused by natural or anthropogenic pollution of water sources. Hematological indicators are therefore considered an important tool to identify the functional state of the body in response to various stressors [5]. However, for the correct interpretation of the obtained results, it is necessary to consider a set of variables, such as reproductive cycle, age, sex, feeding behavior, stress, nutritional status, and water quality, as well as the habitat of the species, since poikilothermic animals are under the impact of environmental changes [6].

Hematological disorders in boteleost include anemia, polycythemia, abnormal morphology, and cytoplasmic and nuclear inclusions [4], and according to Witeska [3], they also include changes in the size and color of erythrocytes.

#### *Erythrocytes and Hemoglobin of Fish: Potential Indicators of Ecological Biomonitoring DOI: http://dx.doi.org/10.5772/intechopen.107053*

Anemia is well described in teleost. It is defined as a decrease in hemoglobin concentration below the reference level of an established threshold for a population of healthy organisms [7]. In teleost it is extremely difficult to establish reference values for hematological parameters, due to their strong variation caused by their poikilothermism and high sensitivity to the action of various factors (age, sex, water quality, photoperiod, season, diet, etc.). For example, hematocrit values strongly depend on the level of biological activity of the fish. Thus, actively swimming species such as tuna and other pelagic species generally have much higher hematocrit values than bottom-dwelling fish such as flatfish. Therefore, hematological parameters are very relative, and there is no clear definition of normal and abnormal values [8]. Therefore, anemia in fish is usually recognized by a significant reduction in red blood parameters compared with the values obtained for a reference group of animals not exposed to the specific damaging factor. According to Clauss et al. [4], hematocrit values (PCV) below 20% are indicative of anemia. The hematological parameters that are affected when anemia occurs in fish are mainly: red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin content (MCH), and mean corpuscular hemoglobin concentration (MCHC). Examination of these indicators (along with WBC values) is recommended for routine monitoring of fish health status in fish farms [9].

Anemia in teleost fishes occurs under both natural and aquaculture conditions and can be caused by various effects, including the toxic effect of a number of pollutants in water bodies (nitrates, pesticides, heavy metal ions, cyanobacterial toxins, etc.) [3].

Depending on the causes of anemia, it can be hemorrhagic, hemolytic, or hypoplastic. Depending on the manifestations, the different types of anemia in fish are divided into microcytic, normocytic, and macrocytic (depending on the size of the erythrocytes), as well as hypochromic or normochromic (depending on the hemoglobin concentration) [4].