**3. Case 3**

In this section we look in a little more detail at Case 3 which involves a direct link between the human brain/nervous system and technology, in particular computers and artificial intelligence. However the main point of interest is that the connection is for therapeutic purposes. That said, part of the reason for detailing this section is to see how easy it is for a case 3 example to become case 4 merely by means of software changes.

### *3.1. Deep Brain Stimulation*

Deep Brain Stimulation is a procedure employed for the electronic treatment of Parkinson's disease, epilepsy, Tourette's syndrome and clinical depression. The deep brain electrodes can though be connected bi-directionally with a computer such that electrical activity in the brain can be monitored. Ongoing research is developing an 'intelligent' stimulator. This uses artificial intelligence to produce warning signals before Parkinsonian tremors begin [20]. So the stimulator only needs to generate signals occasionally rather than continuously, thus operating in a similar fashion to a heart pacemaker.

Using AI techniques, by better understanding the nature of the disease it has been found that there are distinct types of Parkinson's disease based on the different nature of the electrical activity in the brain [13]. It is also quite possible for the monitoring computer to be located remotely from the patient. Hence, signals within the brain can be tracked in real time and fed into a computer. The computer is

able to analyse these signals and generate alternative signals that are fed directly back into the brain in order to ensure the person in question continues to function.

Clearly whilst stimulation is provided in a particular part of the brain merely to overcome a specific problem so we are dealing with a case 3 situation. However if the implant is shown to be successful in other ways then the situation could change. As an example when the implant is employed to overcome depression it is an interesting application, giving the individual positive feelings. This could readily be extended for the computer to bring about positive feelings under certain circumstances and negative feelings in other cases.


**Contents**

## **About the Special Issue Editor**

**Kyong Yop Rhee** has been a professor of mechanical engineering at Kyung Hee University (South Korea) since 1999. His main research interests are nanocomposites, surface treatment, fracture, fatigue and composite materials. He has published 361 scientific papers in leading international journals, and he has led 67 R&D projects. His current h-index is 46. He earned his BS and MS degrees in Mechanical Engineering at Seoul National University (South Korea). He earned his PhD in Mechanical Engineering at Georgia Institute of Technology, after which he completed a two-year postdoctoral fellowship at Rutgers University.

## *Editorial* **Electronic and Thermal Properties of Graphene**

## **Kyong Yop Rhee**

Department of Mechanical Engineering, College of Engineering, Kyung Hee University, Yongin 446-701, Korea<EMAIL_ADDRESS>
Received: 30 April 2020; Accepted: 5 May 2020; Published: 11 May 2020

Recently, the development of nanotechnology has bloomed in numerous industries. In this regard, graphene, a two-dimensional carbon nanomaterial, has been extensively researched, due to its high academic interests and commercial potential. Due to its unique structure and outstanding material properties, the research on graphene has enabled substantial progress in the development of electronics devices, thermoelectric appliances, optical devices, sensors, and energy harvesting applications. In addition, the mechanical properties, such as young modulus (1TPa), intrinsic strength (130 GPa), high sti ffness, and fracture strain, make graphene a promising candidate for industries like nanocomposite coatings, paints, and bioapplications [1]. The development of graphene and graphene-based nanocomposites is always under intensive research, to provide the foundations for next generation devices. In this framework, the present special issue explored recent advances in the graphene based devices and their applications in next generation electronics. Here, we have discussed remarkable electronic and thermal properties of graphene such as Dirac fermions, high electrical conductivity, high seebeck coe fficient, the quantum hall e ffect and thermoelectric e ffects [2]. This special issue compiles 19 articles dedicated to thermal, electrical and thermoelectric properties of graphene: 14 research articles and five review articles.

Graphene shows numerous novel and inimitable physical properties, such as the anomalous quantum hall e ffect, the ambipolar electric field e ffect, Klein tunneling, and ballistic transport, due to its exclusive crystal and electronic structure. However, the band gap characteristics of graphene limits its applications and commercial interests. The properties of graphene can be tuned by altering its nanostructure in terms of boundary configuration, structural defects, chemical doping, and the formation of heterogeneous structures to meet the demands of the electronic, photo thermal, thermoelectric and photoelectric fields [3]. High energy density and low cost are the prerequisite conditions for next generation transportation and grid storage. Lithium sulfur batteries are widely popular in this respect, however, due to their low active material utilization and poor life cycle, Hearin Jo et al. [4] use carbon coated separators with di fferent ratios of carbon black and vapor grown carbon fibers to inhibit the migration of the soluble polysulfide, preventing it from reaching to the Li metal surface. Hong et al. [5] prepared carbon foam from carboxymethyl cellulose and compared enhancement in the thermal conductivity of neat carbon foam (CF), and carbon foam with Ag (CF-Ag), Al (CF-Al), CNT (CF-CNT), and graphene (CF-G). Their studies showed higher thermal conductivities of CF-Ag, CF-Al, CF-CNT, and CF-G, compared to CF. Among all the CF, the phase change temperature is the fastest for CF-G. In addition, the SEM analysis showed e ffective impregnation of erythritol into the pores of carbon foams, which minimized the latent heat loss during thermal cycling. Therefore, these CF impregnated with erythritol represents promising material for thermal energy storage applications. Jhao Yi Wu et al. [6] reported a facile process to synthesize few layer graphene (FLG) from graphite by a liquid exfoliation process. The similar D/G ratio of FLG and graphite demonstrates generation of very few structural defects. The FLG/polyvinylidene difluoride thin films showed superior electrical conductivity with great flexibility and mechanical strength under bending conditions, and have immense potential in conductive adhesive applications. The manuscript by Maoyuan Li [7] and Huaipeng Wang [1] discussed molecular dynamics simulations (MDS) to study the

mechanical properties of graphene and carbon honeycomb (CHC). Maoyuan Li et al. investigated the effects of temperature, strain rate, and defects in the mechanical properties of graphene. Their results indicate a reduction in the Young modulus, fracture strength, and fracture strain with increases in the temperature. The existence of defects in graphene hampers the mechanical properties significantly, due to local stress concentration points, whereas the thermal conductivity showed a low temperature dependent behavior. In a similar study, Huaipeng Wang et al. presents an interesting insight between the covalent bonds of hinge atoms of CHC and their plastic behavior.

The special issue is completed with review papers [2,3,8,9], which compile recent research findings on the thermal, electrical, and thermoelectric properties of graphene and its composites. In addition, the application of graphene in the development of electrochemical biosensors was also discussed. Chao Lv et al. [10] discussed recent developments and the potential of graphene-based humidity sensors in their review paper.

In summary, this special issue of nanomaterials entitled *"Electronic and Thermal Properties of Graphene"* compiles a series of original research articles and recent review papers to provide depth information on the development of graphene based next generation devices. We hope that this special issue will provide an interesting insight into the latest perspectives in this rapidly evolving industry.

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

**Conflicts of Interest:** The author declare no conflicts of interest.


**8. Ecosystem services from agroforestry systems**

According to the 2005 Millennium Ecosystem Assessment, human beings are relished by supporting, regulating, provisioning, and cultural services from the ecosystem. They have become the most widely used framework to study the relations between ecosystems (including natural and human-modified ecosystems) and people [70]. Agroforestry has been demonstrated to combine production

*Agroforestry - Small Landholder's Tool for Climate Change Resiliency and Mitigation*

structure, and pore size distribution [53].

grass buffer system in comparison to the row crop system.

**7. Agroforestry in climate change mitigation potential**

Assam lemon (*Citrus lemon* L.) + annual agricultural crops; Arboretum (Mixed multipurpose tree species) + annual agricultural crops; Silvi-hortipastoral [alder (*Alnus nepalensis*) + pineapple (*Ananus sqennnsa* L.) + fodder and multistoried AFS [alder +tea (*Camellia sinensis*) + black pepper + annual agricultural crops]. The soil physical properties such as bulk density (BD), mean weight diameter (MWD) and apparent saturated hydraulic conductivity (AHC) were compared with the soil from the adjoining area of natural forest soils of same age. The mean bulk density of soil from natural forest was least (0.94 Mgm−3) and highest for Khasi mandarin and Assam lemon (1.19 Mgm−3). The bulk density was less for natural forest and other agroforestry systems due to heavy litter fall and decay of dead roots resulting in high organic carbon content [8]. Soil aggregates were represented with MWD which was observed highest for natural forest i.e., 3.13 and lowest in case of Assam lemon i.e., 1.39. The value of MWD is in the order as natural forest>multistoried AFS > Silvi-hortipastoral>Arboretum>Khasi mandarin>Assam lemon. The value of MWD was highest for natural forest due to more availability of organic matter content which helps in forming the aggregates. The reason for being a low value of MWD for Arboretum, Khasi mandarin and Assam lemon may be attributed to the frequent use of agricultural implements that disintegrate the soil structure. In all agroforestry systems, hydraulic conductivity was inversely related to soil depth. AHC signifies the rate of water movement through the soil profile. AHC was found rapid in natural forest (1.84 x 10−4 m/s) and least in case of Khasi mandarin system (0.38x 10−4 m/s). AHC varied for different agroforestry systems as Natural forest>multistoried AFS > Silvi-hortipastoral>Arboretum>Assam lemon> Khasi mandarin. This study concludes among the agroforestry system, multistoried AFS and Silvi-hortipastoral improves more soil moisture conservation capability, soil

An increase in porosity was reported by Udawatta et al. [54] in the Midwest Region of the United States in maize-soybean field in conjunction with using agroforestry buffers. In grass and agroforestry buffer strips pore path was observed three and five times higher than in soil of maize-soybean field which may be a reason for increased infiltration rate. Pandey et al. [55] reported that the sand particles declined by 10% and 9%; clay particle increased by 14% and 10% under midcanopy and canopy edge respectively compared to under canopy gap position. Silt particles quantity was not influenced by canopy position. Soil organic carbon, total N, total P were more under mid-canopy and canopy edge compared to the canopy gap. Seobi et al. [33] observed improved soil physical properties in agroforestry and

Agroforestry system acts as an atmospheric carbon sink and in carbon sequestration process, carbon is captured from the atmosphere and stored as carbon sink such as by oceans, vegetation and soils through certain biological and physical processes. Agroforestry system traps more atmospheric carbon compared to crop plants or pastureland [56, 57]. The capacity of agroforestry systems to sequester carbon depends on different factors such as tree species, age of tree, tree density, climate, geographical location, and management practices. In general, tropical humid climate sequestrates more carbon than arid, semi-arid, temperate region. On an average soil organic carbon pool in the soils of arid climate and cold region below 1 m depth is 30 and 800 tons ha−1 respectively. The total worldwide land area under agroforestry system is 1023 Mha which has potential to sequester carbon

**70**

with multiple ecosystem services and goods [71] it provides multiple ecosystem services, combining the provision of agricultural, livestock and forestry products with regulating services, cultural services and supporting services. In this context, there is a general need to gain more insight into the overall, total functioning of an agroforestry system i.e., a broad picture of the simultaneous and multiple services provided by such a system.

Agroforestry is a viable land-use option that, in addition to the socio-economic benefits, offers several ecosystem services in the face of different environmental and social challenges [37, 72]. Agroforestry promotes multiple ecosystem services like improvement in soil quality, water conservation by slowing down surface runoff, reducing sediment transportation, soil biodiversity, enhances carbon sequestration, and increases diverse food and cover for wildlife habitat [73, 74]. However, being these services much interlinked so are difficult to measure autonomously but agroforestry has the potential to promote economic, environmental, social vitality, and land stewardship [73]. Sileshi et al. [75] while working in eastern and southern Africa reported that when agroforestry properly designed and strategically located, and the practices of agroforestry can contribute to ecosystem services by mitigating land degradation, climate change, and desertification while adding structural and functional diversity to the agricultural landscapes in the Miombo eco-region. Trees on farms can prevent environmental degradation and provides healthy system for human welfare [76]. However, agriculture has changed enormously in the second half of the last century, driven by agricultural policy and technological progress. Trees that characterized many agroecosystems across the globe have been lost to a large extent [77, 78]. Although, promoting the concept of ecosystem services, to better understand the diverse ecosystem services provided by agroforestry is very important to know. In Ethiopia, agroforestry was credited as a sustainable farming practice that uses and conserves biodiversity and limits agricultural expansion into natural forests [79]. However, this farm-based conservation of biodiversity was only recently advocated by the Convention on Biological Diversity [80–82]. If managed properly, agroforestry holds promise for ecosystem services and environmental benefits. The practices of agroforestry can be considered an adaptive strategy in areas with increasing climate variability and can serve as viable carbon sinks as they trap and store carbon.

### **9. Conclusion**

Agroforestry provides goods and services from trees and reinstates degraded lands. The agroforestry system has the potential for making habitats for edge species conservation of remnant intrinsic species and their gene pools. In the wake of food scarcities and predictable climate change, the practices of agroforestry are gaining attention from the researchers and policymakers as a lucrative approach to develop food security, while at the same time backing to climate change adaptation and mitigation. However, to achieve the target of sustainability, we need to practice agroforestry with improved water management and innovative practices. Climate change will intensify constraints by creating weather more inconstant and will influence the yield by a further decrease in average yields worldwide. Changing food habits with an increase in population and water and land scarcity are also longterm trends that threaten our shared vision of a more prosperous future in which well-fed people everywhere can achieve their full potential without damaging their environment. Agroforestry can improve the resilience of agricultural production to current climate variability as long-term climate through the use of trees for intensification and diversification and buffering of farming systems.

**73**

**Author details**

Gopal Shukla4

Jag Mohan Singh Tomar1

University, Jhansi, UP, India

and Raj kumar5

Viswavidyalaya, Cooch Behar, WB, India

provided the original work is properly cited.

5 ICAR-Indian Institute of Soil salinity, Karnal

\*Address all correspondence to<EMAIL_ADDRESS>
, Akram Ahmed2

1 Indian Institute of Soil and Water Conservation, Dehradun, India

2 ICAR Research Complex for Eastern Region (ICAR-RCER), Patna, India

4 Department of Forestry, Faculty of horticulture, Uttar Banga krishi

3 College of Horticulture and Forestry, Rani Lakshmi Bai Central Agricultural

© 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,

, Jahangeer A. Bhat3

\*, Rajesh Kaushal1

,

*Potential and Opportunities of Agroforestry Practices in Combating Land Degradation*

No potential conflict of interest was reported by the author(s).

*DOI: http://dx.doi.org/10.5772/intechopen.97843*

This work was carried out without any funding.

**Funding**

**Conflict of interest**

*Potential and Opportunities of Agroforestry Practices in Combating Land Degradation DOI: http://dx.doi.org/10.5772/intechopen.97843*


2.4.2. Rebound Number

To determine the rebound number of specimens of the six concrete mixtures used in this study, tests were carried out according to the NMX-C-192-ONNCCE-2018 standard [54], in which a procedure is established to determine the rebound index for hardened concrete using a device known as a sclerometer or rebound hammer, to evaluate the compressive strength as well as the surface uniformity of the concrete. The results are considered relative rather than absolute values, but the test has the advantages of being non-destructive and widely used worldwide, and is used for evaluating the compressive strength of in-situ concrete [55] and in conjunction with the UPV test to predict the compressive strength of concrete in studies according to the findings of Amine et al. [56]. A rebound hammer, abrasive stone, spatula, flannel and brush were used to carry out the test. The test surface preparation was at least 150 mm in diameter and 100 mm thick. The surface was free of any layer other than concrete (see Figure 3).

**Figure 3.** Rebound Number test.