**4. Direct digital manufacturing characteristics**

### **4.1 Economics**

Direct digital manufacturing (DDM) is the interconnection of decentralised additive manufacturing equipment and modern information and communication technology (ICT) [7]. DDM combines product design with manufacturing technology, usually 3D printing or additive manufacturing, to directly convert digital models into physical objects without the need for tooling. DDM uses 3D (CAD) models for direct fabrication of products without the need for process planning [36].

The use of DDM as a broad umbrella term encompasses applications in prototyping, tooling, low-volume parts manufacturing and customised product manufacture. Distributed production is a likely outcome of the use of DDM [37] with the expected emergence of agile supply chains [38]. The technology enables the matching of consumer demand and supply capacities in real-time, limited only by physical logistics.

Product characteristics for additive manufacturing are customisation, increased functionality through design optimisation and low volume. Investment in additive manufacturing may be seen as a structural investment which builds new manufacturing capabilities [39].

It is important to distinguish between personal fabrication and social manufacturing [40]. Personal fabrication is when individuals make products for their personal use employing, for example, home 3D printers. Social manufacturing occurs when individuals cooperate with organisations as part of production.

Industrial 3D printers cost around £20,000, but low-cost 3D printers, some of which are self-replicating, are available to the public [41] for about £500. One of the top-rated 3D printers currently on the market sells for about £2600. Some home 3D printers have the capability to print three different materials in one session for 3D prints that have moving parts.

The key perceived strengths of additive manufacturing are agility, in-process visualisation, novel business models, reduced upfront fixed cost and risk, potential for decentralised production, and a reduction in transports [42]. DDM has the potential to dramatically change conventional supply chains if the 'factory in every home that can make more factories' is achieved [41]. The only transport related to home use of products printed at home would be of the raw materials, usually in the form of wire or powder. Cost analysis indicates home manufacturing is a profitable proposition for U.S. households [43, 44].

**69**

*A Sustainability Assessment of Smart Innovations for Mass Production, Mass Customisation…*

Prices and times to print large objects increase exponentially. Even though 3D printed health aids are becoming available, regulating the conformity and quality of products in general is problematic [45]. Other technical challenges include timeconsuming 3D object design, limited types of usable materials, low precision and productivity [46]. Additional labour costs may be incurred for post processing such as removing residual powder – this is often underestimated or neglected [47].

It has been demonstrated that 3D printing may be applied to mass production/ mass customization [46, 48, 49]. The advantages of 3D printing over conventional mass production methods include saving time, money and effort in creating the dedicated capacity and materials, prototyping and moulding. A quicker response may be achieved by using multiple 3D printing facilities simultaneously in a local area using industrial Internet of Things (IIoT) technology and maximising the

Mass imagineering digital infrastructures may require a high level of technology awareness. Internet-enabled global networking may provide the means for financial rewards at almost no financial risk, but time may need to be invested. There may,

Research has found that the key driver for adoption of additive manufacturing is the capability of producing almost any complex design with economic motives

The toxicological and environmental hazards of handling, using and disposing of materials used in DDM processes are not fully understood. Compared to processes such as casting, forging and machining, workers do not experience long-term exposure to noise and oil mist from metal working [52]. However, 3D printing is being associated with the release of volatile and very volatile organic chemicals and billions of airborne particles per minute with potential for inhalation and consequent health risks [53, 54]. Although many industrial 3D printers are enclosed, workers may still be exposed to inhalation risks when retrieving the printed parts. Occupational exposure limits have yet to be established for 3D printer emissions [55]. As with any new technology, these issues should be resolved over time.

The premise behind DDM is that designs will be co-created through collaboration. Acquiring the necessary skills may be possible online using basic knowledge of computers. This may enable promises of equality, justice and self-actualization. But this may also lead to the exploitation of individuals who may or may not realise that digital infrastructures are collecting their personal data and that they are doing unpaid work [56, 57]. Work that is paid may be poorly paid, precarious and intermittent. For profitable mass production using DDM, design is likely to be key and the extent to which co-created designs may outperform those of traditional mass

Furthermore, there is no absolute geometric freedom and many considerations for eco-design which existing methods and guidelines for conventional manufacturing do not cover indicate that to realise the full potential of DDM for more complex products, specialist designers may be required [58]. Design for do-it-yourself is

Very little sustainability research has examined personal fabrication, social manufacturing or even the industrial use of DDM in distributed production [37]. The environmental implications of these evolving manufacturing processes have

*DOI: http://dx.doi.org/10.5772/intechopen.88897*

however, be risks to personal reputation [50].

production or mass customization remains to be seen.

under-explored in academia [59].

**4.3 Environment**

closeness to JIT [8].

being pivotal [51].

**4.2 Workforce**

#### *A Sustainability Assessment of Smart Innovations for Mass Production, Mass Customisation… DOI: http://dx.doi.org/10.5772/intechopen.88897*

Prices and times to print large objects increase exponentially. Even though 3D printed health aids are becoming available, regulating the conformity and quality of products in general is problematic [45]. Other technical challenges include timeconsuming 3D object design, limited types of usable materials, low precision and productivity [46]. Additional labour costs may be incurred for post processing such as removing residual powder – this is often underestimated or neglected [47].

It has been demonstrated that 3D printing may be applied to mass production/ mass customization [46, 48, 49]. The advantages of 3D printing over conventional mass production methods include saving time, money and effort in creating the dedicated capacity and materials, prototyping and moulding. A quicker response may be achieved by using multiple 3D printing facilities simultaneously in a local area using industrial Internet of Things (IIoT) technology and maximising the closeness to JIT [8].

Mass imagineering digital infrastructures may require a high level of technology awareness. Internet-enabled global networking may provide the means for financial rewards at almost no financial risk, but time may need to be invested. There may, however, be risks to personal reputation [50].

Research has found that the key driver for adoption of additive manufacturing is the capability of producing almost any complex design with economic motives being pivotal [51].

### **4.2 Workforce**

*Mass Production Processes*

likely to be process efficiency.

**4.1 Economics**

physical logistics.

turing capabilities [39].

prints that have moving parts.

proposition for U.S. households [43, 44].

strategy.

customised product. If the mass customised product is not self-reconfiguring and does not contain custom fabricated components, remanufacturing is a good EOL

The modularity of customised products would likely make them more amenable to upgrading than mass-produced products that do not have this modularity. Modularity would also assist with remanufacturing and recycling. Modular mass customised products may be easier to disassemble than mass produced products that are not modular. Modular product architecture may improve recyclability if it is

If a modular design is standardised across multiple products, considerations of material usage and end of life are likely to be issues of concern. If a modular design is assumed but cannot be standardised across multiple products, the most pressing environmental consideration for the manufacturer of mass customised products is

Direct digital manufacturing (DDM) is the interconnection of decentralised additive manufacturing equipment and modern information and communication technology (ICT) [7]. DDM combines product design with manufacturing technology, usually 3D printing or additive manufacturing, to directly convert digital models into physical objects without the need for tooling. DDM uses 3D (CAD) models for direct fabrication of products without the need for process planning [36]. The use of DDM as a broad umbrella term encompasses applications in prototyping, tooling, low-volume parts manufacturing and customised product manufacture. Distributed production is a likely outcome of the use of DDM [37] with the expected emergence of agile supply chains [38]. The technology enables the matching of consumer demand and supply capacities in real-time, limited only by

Product characteristics for additive manufacturing are customisation, increased functionality through design optimisation and low volume. Investment in additive manufacturing may be seen as a structural investment which builds new manufac-

It is important to distinguish between personal fabrication and social manufacturing [40]. Personal fabrication is when individuals make products for their personal use employing, for example, home 3D printers. Social manufacturing occurs when individuals cooperate with organisations as part of production.

Industrial 3D printers cost around £20,000, but low-cost 3D printers, some of which are self-replicating, are available to the public [41] for about £500. One of the top-rated 3D printers currently on the market sells for about £2600. Some home 3D printers have the capability to print three different materials in one session for 3D

The key perceived strengths of additive manufacturing are agility, in-process visualisation, novel business models, reduced upfront fixed cost and risk, potential for decentralised production, and a reduction in transports [42]. DDM has the potential to dramatically change conventional supply chains if the 'factory in every home that can make more factories' is achieved [41]. The only transport related to home use of products printed at home would be of the raw materials, usually in the form of wire or powder. Cost analysis indicates home manufacturing is a profitable

possible to concentrate material fractions by module.

**4. Direct digital manufacturing characteristics**

**68**

The toxicological and environmental hazards of handling, using and disposing of materials used in DDM processes are not fully understood. Compared to processes such as casting, forging and machining, workers do not experience long-term exposure to noise and oil mist from metal working [52]. However, 3D printing is being associated with the release of volatile and very volatile organic chemicals and billions of airborne particles per minute with potential for inhalation and consequent health risks [53, 54]. Although many industrial 3D printers are enclosed, workers may still be exposed to inhalation risks when retrieving the printed parts. Occupational exposure limits have yet to be established for 3D printer emissions [55]. As with any new technology, these issues should be resolved over time.

The premise behind DDM is that designs will be co-created through collaboration. Acquiring the necessary skills may be possible online using basic knowledge of computers. This may enable promises of equality, justice and self-actualization. But this may also lead to the exploitation of individuals who may or may not realise that digital infrastructures are collecting their personal data and that they are doing unpaid work [56, 57]. Work that is paid may be poorly paid, precarious and intermittent. For profitable mass production using DDM, design is likely to be key and the extent to which co-created designs may outperform those of traditional mass production or mass customization remains to be seen.

Furthermore, there is no absolute geometric freedom and many considerations for eco-design which existing methods and guidelines for conventional manufacturing do not cover indicate that to realise the full potential of DDM for more complex products, specialist designers may be required [58]. Design for do-it-yourself is under-explored in academia [59].

#### **4.3 Environment**

Very little sustainability research has examined personal fabrication, social manufacturing or even the industrial use of DDM in distributed production [37]. The environmental implications of these evolving manufacturing processes have

not been extensively examined [47]. The focus of research has been on sustainable development through additive manufacturing by (1) improved resource efficiency permitted by redesign of both products and processes for in-house waste minimisation; (2) product life extension using technical approaches and stronger personproduct relation; and (3) simplified value chains by reduction of logistic complexity and placing production nearer to the consumer [60].

Environmental effects such as biodegradability and ecotoxicity are not fully understood. Similarly, little is known about the chemical solvents used for removing excess material during the steriolitography (SLA) process as well as environmental effects related to selective laser sintering (SLS), laser additive manufacturing (LAM), dynamic magnetic compression (DMC) and direct metal fabrication (DMF) [61].

Evaluation of the energy consumption has not been thoroughly investigated [51] nor has water consumption and treatment [61]. Polymers, the most processed type of powders in SLS, have quite a low sintering temperature (<200°C). A partial consideration of SLS which does not include the efficiency of the laser source or auxiliary energy finds a low energetic intensity of the process, but there is no direct comparison possible with other rapid prototyping techniques or conventional manufacturing processes from the quality perspective [62]. Smaller thickness layer and optimal part orientation may overcome surface quality issues, but processing time and thus energy consumption is increased [58].

Additive as opposed to subtractive manufacturing may help to reduce material input into production. Not all material from DDM is reclaimable. Powder bed processing of polymers causes up to 50% of the build volume in waste which cannot be reused. Significant energy may be required in the production of the required raw materials (feedstock), but there may be significant saving if recycling is possible [47]. There is potential to combine surplus agricultural materials such as soybean to create composites of comparable strength to those made from petroleum-based resins [63] or to utilise local waste streams (mussel shells) [64].

Energy savings may be obtained through reduced material demand and use phase savings due to lighter weight. However, the benefits of components produced through additive manufacturing versus traditional manufacturing are questionable for automotive components when considered in the context of additional manufacturing impacts caused by powder production, processing and post treatment [65]. Some authors have concluded that it is not possible to determine whether 3D printing is more environmentally friendly that machining or vice versa [66].

It is likely that hybrid additive manufacturing and subtractive manufacturing will be desirable so there will be a need for intelligent algorithms to determine process parameter combinations. With multiple additive manufacturing systems, an intelligent factory with resource allocation and self-organisation capabilities would be optimal [58]. An investigation of DDM-based operational practices to build sustainability capabilities anticipates increased local supply chain partners, reduced material flows, inventory and transport operations, and more sustainable product lifecycle management [67]. However, many of these operations are likely to be complex such as the addition of sensors to products, the extent of customer control over the production process and dynamic supply chain reconfiguration.

Distributed manufacturing may significantly reduce transports over centralised manufacturing [68], however, raw material transport may offset some of these benefits. There is a significant risk that additive manufacturing may trigger a rebound effect through an increase in overall consumption, especially in fashion products [69]. It is also not clear whether mass customization in DDM will precisely match consumer needs and thus eliminate waste, or if the availability of DDM will increase waste through trial productions. Environmental sustainability benefits are

**71**

*A Sustainability Assessment of Smart Innovations for Mass Production, Mass Customisation…*

barely relevant to the decision of manufacturers to adopt additive manufacturing which contrasts with literature stating the considerable sustainability benefits [51]. The eco-design concept enabled by additive manufacturing has the most potential for providing sustainability improvements [58]. Symbiotic, life cycle and closed loop links could significantly reduce or eliminate the negative impacts of additive manufacturing. Improved design has the potential to increase market acceptance which may lead to reduced waste. Additive manufacturing has potential to provide spare parts and impact the modularity of products relevant to circular economy efforts [70]. As additive manufacturing may be used to repair or remanufacture damaged components, savings of up to 50% may be achieved [47]. More efficient designs may be possible with additive manufacturing as well as the integration of

Cyber-physical systems (CPS) facilitate the connection and communication of software and mechanical or electrical elements using wired or wireless data infrastructure. This technology makes it possible to monitor and direct production systems with complex processes at all hierarchy levels and with high product varieties. The anticipated paradigm shift in manufacturing to Industry 4.0 or smart factories and production systems will decentralise traditional centralised applications for production control [71]. Industry 4.0 innovations/technical developments

2.M2M meaning machines will communicate with each other to improve process flow, do capacity planning and reduce process time. This will include the monitoring of components for wear to prevent or reduce breakdowns.

3.RFID and NFC technology enable wireless communication. This technology is currently used in warehouse management and logistics, product tracking in supply chains, product security, raw material tracking, point of sale, and other

4.QR codes used to identify parts or tools, or provide more information about a

5.Augmented reality to display additional information such as instructions, or to help with visualisation of objects in a physical space. Simulation may enable quality control so that potential defects may be corrected prior to physical

6.Mobile devices that may be used to give instructions to workers, apps may monitor or control machines, machines may be tracked via QR codes, and

7.Condition monitoring/predictive maintenance reduces unscheduled machine stoppages using electric motors to measure and track data about mechanical stress and operating temperature which are usually sent to a cloud for storage and analysis. This reduces waste as parts are replaced after they are worn as

images or videos may be sent as part of support or service.

opposed to after a pre-defined life.

*DOI: http://dx.doi.org/10.5772/intechopen.88897*

additional technical functionality [47].

**5. Smart production innovations**

applications.

product.

production.

which will enable this paradigm shift include [72]:

1.Cobots that will assist workers in handling physical objects.

*A Sustainability Assessment of Smart Innovations for Mass Production, Mass Customisation… DOI: http://dx.doi.org/10.5772/intechopen.88897*

barely relevant to the decision of manufacturers to adopt additive manufacturing which contrasts with literature stating the considerable sustainability benefits [51].

The eco-design concept enabled by additive manufacturing has the most potential for providing sustainability improvements [58]. Symbiotic, life cycle and closed loop links could significantly reduce or eliminate the negative impacts of additive manufacturing. Improved design has the potential to increase market acceptance which may lead to reduced waste. Additive manufacturing has potential to provide spare parts and impact the modularity of products relevant to circular economy efforts [70]. As additive manufacturing may be used to repair or remanufacture damaged components, savings of up to 50% may be achieved [47]. More efficient designs may be possible with additive manufacturing as well as the integration of additional technical functionality [47].


Fresh leaf sample (each 500 mg) was crushed in polyvinyl pyrrolidone solution (1%) and cold potassium phosphate buffer (pH 7.0, 100 mM) for extracting the antioxidant enzymes. The mixture was centrifuged at 4 ◦C at 12,000 *g* for 30 min. The supernatant was collected and used for determining the activities of SOD, CAT, APX and GR.

#### 4.8.1. Superoxide Dismutase (SOD, EC<IP_ADDRESS>) Activity

The activity of SOD was determined by monitoring the diminishing of NBT (nitro blue tetrazolium) photochemically by the enzyme extract [66]. The OD was recorded at 560 nm and the SOD activity was presented as EU mg-1 protein.

#### 4.8.2. Catalase (CAT, EC<IP_ADDRESS>) Activity

The CAT activity was evaluated by the protocol given by Aebi [67] and disappearance of H2O2 was recorded for 2 min at 240 nm. The CAT activity was presented as EU mg-1 protein.

#### 4.8.3. Ascorbate Peroxidase (APX, EC<IP_ADDRESS>) Activity

APX activity was assayed by monitoring the H2O2-dependent oxidation of ascorbate at 290 nm for 2 min (Nakano and Asada 1981). The APX activity was presented as EU mg−1 protein.

#### 4.8.4. Glutathione Reductase (GR, EC<IP_ADDRESS>) Activity

The GR activity was assayed by the procedure described by Foster and Hess [68]. The absorbance was taken at 340 nm for 3 min and the GR activity was presented as EU mg−1 protein.

#### 4.8.5. Monodehydroascorbate Reductase (MDHAR, EC<IP_ADDRESS>) Activity

The protocol described by Miyake and Asada [69] was employed for the assay of MDHAR. The OD was recorded at 340 nm and the activity was presented as µmol NADPH oxidized (EU mg−1 protein).

#### 4.8.6. Dehydroascorbate Reductase (DHAR, EC<IP_ADDRESS>) Activity

Nakano and Asada [70] protocol was exercised for the assay of DHAR activity and the OD was taken at 265 nm. The DHAR activity was presented as EU mg−1 protein.

#### 4.8.7. Ascorbic Acid (AsA) and Glutathione

The methods described by Huang, et al. [71] and Yu, et al. [72] were followed for the assay of ascorbate and glutathione content, respectively.

#### *4.9. Estimation of Methylglyoxal (MG), Gly I (EC<IP_ADDRESS>) and GlyII (EC<IP_ADDRESS>)*

The protocol of Wild, et al. [73] was used for the determination of MG content and the OD was taken at 288 nm. For determining the activities of Gly 1 and Gly II, the protocols given by Hossain, et al. [74] and Mostofa and Fujita [75], respectively, were used. The OD was recorded at 240 nm and the enzymes' activities were expressed as µmol mg−1 min−1 protein.

#### *4.10. Estimation of As in the Shoot and Root*

The dry tissue (each 500 mg) was digested in an acid mixture and the concentration of As was quantified by an atomic absorption spectrophotometer (Perkin-Elmer Analyst Model 300, NJ, USA).

#### *4.11. Statistical Analysis*

The SPSS statistical software version 17.0 (SPSS, Inc., Chicago, USA) was used for analysis of variance of each data set and the mean values were compared using Duncan's multiple range test (DMRT) at *p* ≤ 0.05. The data presented are mean± SE and *n*= 5.

#### **5. Conclusions**

This study marks that ZnO–NPs are efficient ameliorators of As toxicity in soybean plants at different concentrations. Thus, if used at certain specific doses, ZnO–NPs could prove to be an excellent foliar fertilizer in areas that are prone to arsenic exposure. The use of these nanoparticles can increase the efficiency of cropping systems by mitigating As stress and promoting the yield of plants.

**Author Contributions:** P.A., M.N.A. and M.A. drafted the experimental design and P.A. and M.N.A. performed the experiments. A.A.A.-H., M.A.A. and L.W. helped in writing the initial draft of the manuscript. A.A.A.-H., C.K. and A.B. analyzed the data. P.A., M.N.A. and M.A. revised the manuscript to the present form. All authors have read and approved this manuscript for publication.

**Funding:** Research Group No. RGP-231.

**Acknowledgments:** The authors also extend their appreciation to the Deanship of Scientific Research at King Saud University for supporting this work through Research Group No. RGP-231.

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

#### **References**

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

MDPI St. Alban-Anlage 66 4052 Basel Switzerland Tel. +41 61 683 77 34 Fax +41 61 302 89 18 www.mdpi.com

*Plants* Editorial Office E-mail<EMAIL_ADDRESS>www.mdpi.com/journal/plants

MDPI St. Alban-Anlage 66 4052 Basel Switzerland

Tel: +41 61 683 77 34 Fax: +41 61 302 89 18

www.mdpi.com ISBN 978-3-0365-4141-9


**Author details**

(9) tendency regulators' behavior

(12) one's own mediating behavior

(13) development of competencies/skills

(11) effects of one's own behavior on oneself

**c.** Alteration of one's own behavior includes user's changes according to his/her own

**d.** Alteration of macrocontingential practices consists of the possible changes of the user's

(17) another person's behavior that changes one's own and/or others' assessment practices

A general description of the contingential analysis was made in this chapter, trying to generate reader's interest in the topic. It overpasses our purpose to illustrate the full application of the analysis, but we recommend reading more about it. This methodology has been successfully applied in a clinical context with different main complaints such as parent-child relationships, fear to walk among elder people, violent familiar relationships, and couples' problems, among many others [15–18]; in a health context where with the basis of the psychological model of biological health and contingential analysis, several researches had been made to understand and change diabetes risk behaviors and HIV risk behaviors, among others [19–25]; in an education context, assessing instructional models to teach contingential analysis, analyzing therapeutic relationships, or developing educative educational workshops for diabetic patients [26–29]; and in a work context developing models and tools to

Considering the fact that the methodology results from an interbehavioral theory, that is, a general human behavior theory, it enables to approach behavior in different professional contexts, in a coherent manner with a scientific position and giving clarity, coherence, and relevance to the application of scientific knowledge; in this regard, this methodology constitutes an alternative to professional psychology. Also, the heuristic value of this approach and the link with basic science must be considered. If we go for a scientific psychology, we need to

consider that the adjective *applied* refers to basic and scientific knowledge.

**e.** Without change: this is the last category that refers to a lack of change by the user.

(14) establishment of behaviors that alter the effects of other behaviors

(15) own behavior that alters others' assessment practices

(16) own behavior to be adjusted to others' assessment practices

(10) mediators' behavior

assessment practice.

**8. Final comments**

assess laboral competences [30–32].

behavior.

38 Behavior Analysis

María de Lourdes Rodríguez Campuzano\*, Antonia Rentería Rodríguez and Norma Yolanda Rodríguez Soriano

\*Address all correspondence to<EMAIL_ADDRESS>
Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, México City, México


*<IP_ADDRESS> Single nucleotide polymorphism (SNP)*

Heritable polymorphism resulting from a single base pair change. SNPs generally have only two alleles.

#### *<IP_ADDRESS> Linkage*

In genetics, refers to how two genes that are nearby to one another on the same chromosome are often inherited together (Glossary. Nature) [9].

#### *<IP_ADDRESS> Linkage disequilibrium*

Describes the state of two genotypes at different loci being dependent, showing a correlation; does not require gene linkage (Glossary. Nature) [9].

### *<IP_ADDRESS> Linkage equilibrium*

The association of two alleles at two or more loci at the frequency predicted by their individual frequencies (Glossary. Nature) [9].

### *<IP_ADDRESS> Segregational analysis*

The process of fitting formal genetic models to data on expressed disease characteristics (phenotype) in biological family members in order to determine the most likely mode of inheritance for the trait or disease under study. (NCI"s Dictionary of Genetic terms) [10].

### *<IP_ADDRESS> Histone modification*

A histone modification is a covalent post-translational modification (PTM) to histone proteins which includes methylation, phosphorylation, acetylation, ubiquitylation, and sumoylation. The PTMs made to histones can impact gene expression by altering chromatin structure or recruiting histone modifiers. (What is epigenetics).

### *<IP_ADDRESS> Linkage analysis*

Study aimed at establishing linkage between genes. Today linkage analysis serves as a way of gene-hunting and genetic testing (Webster's New World medical dictionary) [11].


**Appendix A**

**Table A1.** Mobility parameters [19].

**Table A2.** Incomplete ionization parameters [19].

## **References**

**Alexander A. Lebedev 1,\* , Vitali V. Kozlovski 2 , Klavdia S. Davydovskaya 1 and Mikhail E. Levinshtein 1**

**Abstract:** The radiation hardness of silicon carbide with respect to electron and proton irradiation and its dependence on the irradiation temperature are analyzed. It is shown that the main mechanism of SiC compensation is the formation of deep acceptor levels. With increasing the irradiation temperature, the probability of the formation of these centers decreases, and they are partly annealed out. As a result, the carrier removal rate in SiC becomes ~6 orders of magnitude lower in the case of irradiation at 500 ◦C. Once again, this proves that silicon carbide is promising as a material for high-temperature electronics devices.

**Keywords:** silicon carbide; radiation hardness; proton and electron irradiation; charge removal rate; compensation; irradiation temperature

**Citation:** Lebedev, A.A.; Kozlovski, V.V.; Davydovskaya, K.S.; Levinshtein, M.E. Radiation Hardness of Silicon Carbide upon High-Temperature Electron and Proton Irradiation. *Materials* **2021**, *14*, 4976. https://doi.org/10.3390/ ma14174976

Academic Editor: Fabrizio Roccaforte

Received: 30 July 2021 Accepted: 26 August 2021 Published: 31 August 2021

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

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

## **1. Introduction**

One of the stimuli in development of the technology of wide-bandgap semiconductors and creating devices on their basis is the high presumed radiation hardness of these materials. Indeed, making higher binding energy of atoms in the lattice of a semiconductor requires a higher energy of particles needed to disintegrate this lattice. Studies carried out in the 1960s demonstrated that silicon carbide substantially surpasses silicon in the radiation hardness [1]. Later, with increasing structural perfection of SiC and decreasing level of background doping, the difference in radiation hardness between SiC and Si decreased. It is noteworthy that the decrease in radiation hardness with the increasing quality of material is also characteristic for other semiconductors. Various structural defects and uncontrollable impurities could serve as drains for radiation defects and, thereby, slow the degradation of material parameters.

However, statements started to appear in the literature suggesting that the radiation hardness of silicon carbide does not surpass, and is even inferior to that of silicon in certain conditions [2–5]. This conclusion seems to be surprising because the energy gap of 4H-SiC (3.2 eV) is nearly three times that of silicon. We found it interesting to consider the situation by using both our results and those of other researchers. Thus, the goal of the present study is to consider the issue of the radiation hardness of silicon carbide and compare it with the similar characteristic for Si.

Our work is focused on the results of high-temperature irradiation, due to the fact that a lot of works have been devoted to the study and analysis of the results of irradiation at room temperature. The great number of published studies are concerned with the radiation hardness of SiC MOSFETs against γirradiation [6–12]. The effect of room temperature electron irradiation on the properties of high-voltage 4H-SiC Schottky diodes also has been studied in many works [13–20]. The effect of room-temperature proton irradiation on the properties of 4H-SiC JBS has been extensively studied [21–28]. Consequently, in this work, we considered it expedient to focus on the results of our work in the field of high-temperature irradiation.


**4.5 Soil management measures for ravines**

In order to meet the nutrient requirements of the crops in ravines, the soil fertility loss due to extreme erosion needs to be compensated accordingly as per specific site. The steep decline in soil fertility in the absence of proper measures to check erosion will cause reduction in the crop yields. This can be achieved in the following manner.


**2.4 Mitochondrial DNA extraction**

G-spin™ Total DNA Extraction Kit (50 Preps) (REF: 17045) was used to extract mitochondrial DNA from blood of different species according to the manufacturer's protocol instructions.

**25**

*Mitochondrial 16S rRNA Gene-Dependent Blood Typing as a Forensic Tool*

**Primer Conditions References**

30 95°C 30 sec

1 72°C 5 min

30 95°C 30 sec

1 72°C 5 min

30 95°C 30 sec

1 72°C 5 min

30 95°C 30 sec

1 72°C 5 min

59.3 °C 30 sec 72°C 130 sec

58.3 °C 30 sec 72°C 130 sec

58.3°C 30 sec 72°C 130 sec

59.3°C 30 sec 72°C 130 sec

1 95°C 2 min This study

1 95°C 2 min This study

1 95°C 2 min This study

1 95°C 2 min This study

*DOI: http://dx.doi.org/10.5772/intechopen.98248*

Homo 16S-F Homo 16S-R

Ovis 16S-F Ovis 16S-R

Capra 16S-F Capra 16S-R

Bos 16S-F Bos 16S-R

**Table 1.** *PCR conditions.*

**2.5 Agarose gel electrophoresis**

**3. Result and discussion**

Agarose gel was prepared by dissolving agarose powder in 1X TBE buffer. The amount of agarose can be dissolved depending upon the purpose in which agarose sheet used. About 0.7% agarose gel was used for visualization of the DNA after extraction while 1.5–2% agarose sheet was used for visualization of PCR product (amplicon). RedSafe (alternative for ethidium bromide) stock solution concentration was 10 mg/ml. Only 5 μl of RedSafe stock solution were added to 100 ml of

The primers were synthesized at Macrogen/Korea, were provided in a lyophilized form, which were re-dissolved with 300 nuclease-free water according to the institution of the manufacture company to reach to the final concentration (100 pmoles/μl). The working solution will be 10 pmoles/μl to be used directly in PCR [15, 16]. The PCR conditions were calculated using online Protocol Optimize writer

The four sets of designed primer pairs were submitted to specificity using Primer-Blast and the results revealed that, they are specific to amplify the 16S rRNA gene of humans (*Homo sapiens*), sheep (*Ovis aries*), goats (*Capra hircus*), and cows

melted agarose gel to get the final concentration of 0.5 μg/ml [13, 14].

**2.6 Primer pairs preparation and PCR conditions**

software. The conditions were illustrated in **Table 1**.

*Mitochondrial 16S rRNA Gene-Dependent Blood Typing as a Forensic Tool DOI: http://dx.doi.org/10.5772/intechopen.98248*

**Table 1.** *PCR conditions.*

*Forensic Analysis - Scientific and Medical Techniques and Evidence under the Microscope*

non-human using a species-specific primer design.

(*Ovis aries*), goat (*Capra hircus*), and cow (*Bos taurus*).

**2. Methodology**

**2.1 Study design**

**2.3 Primer design**

**2.2 Blood sample collection**

profiling methods used for human proof of identity and present their use in the chief cases of human identification from non-human [3–5]. Mitochondrial markers that are used for species identification are as follows: cytb gene, cytochrome c oxidase subunit I gene, 12S and 16S rRNA segment, and control region in wildlife [6–8]. A short fragment of the 12S rDNA was employed for DNA amplification leading to species identification. The mitochondrial DNA 16S rRNA gene is an advanced genetic marker for animal genetic diversity. Polymorphism sites, nucleotide variation, and haplotype variety were determined using whole sequences of the mitochondrial DNA 16S rDNA gene [9, 10]. Animal mitochondrial DNA (mtDNA) is commonly described as a small, circular molecule that is conserved in size, gene content, and organization [11]. The aim of this study is to design valuable species-specific-PCR tool to discriminate blood of humans from

The study design was experimental to design species-specific primer pairs for typing the blood samples and their assignment to human (*Homo sapiens*), sheep

Seventy-two blood samples were collected from humans, sheep, goats, and cows (18 blood samples for each). All blood samples were withdrawn by technicians and 5 ml were aspirated using an aseptic technique and transferred to EDTA-Na2 tubes and mixed well and stored in a refrigerator. The collection took 2 weeks (May 15,

2019–May 30, 2019). All samples were collected from Al-Diwanya city.

Homo 16S-R: ATCATTTACGGGGGAAGGCG (1200 bp); Ovis 16S-F:

(1060 bp); Capra 16S-F: GCCTGGTGATAGCTGGTTGT, Capra 16S-R: TCACCCCAACCAAAACTGCT (820 bp); and Bos 16S-F:

AGGCCTAAAAGCAGCCATCA, Ovis 16S-R: GCCCTTTTCTAGGGCAGGTT

CTAAGCAGCCCGAAACCAGA, Bos 16S-R: GGGCAGGGTTTTGTGTTGTC

G-spin™ Total DNA Extraction Kit (50 Preps) (REF: 17045) was used to extract mitochondrial DNA from blood of different species according to the manufacturer's

The gene selected for this study is the mitochondrial 16S rRNA gene. The NCBI data base was used to recover the sequences chosen for a primer design. The sequence ID of *Homo sapiens* (NC\_012920.1); sequence ID of *Ovis aries* (NC\_001941.1); sequence ID of *Capra hircus* (NC\_005044.2); sequence ID of *Bos taurus* (NC\_006853.1). Primer 3 software [12] was used to design the specific primer using the sequence of above-mentioned sequence IDs. The generated primers were as follows: Homo 16S-F: GCCTGGTGATAGCTGGTTGT,

**24**

(1300 bp).

protocol instructions.

**2.4 Mitochondrial DNA extraction**