Search results for: alternative bed materials

Authors: Emre Bayamlıoğlu

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This paper aims to provide an account of the legal and the regulative aspects of the algorithmic reputation systems with a special emphasis on the sharing economy (i.e., Uber, Airbnb, Lyft) business model. The first section starts with an analysis of the legal and commercial nature of the tripartite relationship among the parties, namely, the host platform, individual sharers/service providers and the consumers/users. The section further examines to what extent an algorithmic system of reputational information could serve as an alternative to legal regulation. Shortcomings are explained and analyzed with specific examples from Airbnb Platform which is a pioneering success in the sharing economy. The following section focuses on the issue of governance and control of the reputational information. The section first analyzes the legal consequences of algorithmic filtering systems to detect undesired comments and how a delicate balance could be struck between the competing interests such as freedom of speech, privacy and the integrity of the commercial reputation. The third section deals with the problem of manipulation by users. Indeed many sharing economy businesses employ certain techniques of data mining and natural language processing to verify consistency of the feedback. Software agents referred as "bots" are employed by the users to "produce" fake reputation values. Such automated techniques are deceptive with significant negative effects for undermining the trust upon which the reputational system is built. The third section is devoted to explore the concerns with regard to data mobility, data ownership, and the privacy. Reputational information provided by the consumers in the form of textual comment may be regarded as a writing which is eligible to copyright protection. Algorithmic reputational systems also contain personal data pertaining both the individual entrepreneurs and the consumers. The final section starts with an overview of the notion of reputation as a communitarian and collective form of referential trust and further provides an evaluation of the above legal arguments from the perspective of public interest in the integrity of reputational information. The paper concludes with certain guidelines and design principles for algorithmic reputation systems, to address the above raised legal implications.

Keywords: sharing economy, design principles of algorithmic regulation, reputational systems, personal data protection, privacy

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Authors: Gobinda Gopal Khan, Ashutosh K. Singh, Debasish Sarkar

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Unique one-dimensional (1D) Ni-NiO and Co-Ni/Co3O4-NiO core/shell nano-heterostructures are fabricated by combining the electrochemical deposition and annealing. The high-performance pseudo-capacitor electrode based on the Ni-NiO and Co-Ni/Co3O4-NiO core/shell nano-heterostructures is designed and demonstrated. The Co-Ni/Co3O4-NiO core/shell nano-heterostructures exhibit high specific capacitance (2013 Fg-1 at 2.5 Ag-1), high energy and power density (23 Wh kg-1 and 5.5 kW kg-1, at the discharge current density of 20.8 A g-1.), good capacitance retention, and long cyclicality. The remarkable electrochemical property of the large surface area nano-heterostructures is demonstrated based on the novel nano-architectural design of the electrode with the coexistence of the two highly redox active materials at the surface supported by highly conducting metal alloy channel at the core for faster charge transport.

Keywords: nano-heterostructures, energy storage, supercapacitors, electrochemical deposition

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Authors: Emiru Birhane, Tesfay Gidey, Haftu Abrha, Abrha Brhan, Amanuel Zenebe, Girmay Gebresamuel, Florent Noulèkoun

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Dracaena ombet and Dobera glabra are two of the most rare and endangered tree species in dryland areas. Unfortunately, their sustainability is being compromised by different anthropogenic and natural factors. However, the impacts of ongoing land use and climate change on the population structure and distribution of the species are less explored. This study was carried out in the grazing lands and hillside areas of the Desa'a dry Afromontane forest, northern Ethiopia, to characterize the population structure of the species and predict the impact of climate change on their potential distributions. In each land-use type, abundance, diameter at breast height, and height of the trees were collected using 70 sampling plots distributed over seven transects spaced one km apart. The geographic coordinates of each individual tree were also recorded. The results showed that the species populations were characterized by low abundance and unstable population structure. The latter was evinced by a lack of seedlings and mature trees. The study also revealed that the total abundance and dendrometric traits of the trees were significantly different between the two land uses. The hillside areas had a denser abundance of bigger and taller trees than the grazing lands. Climate change predictions using the MaxEnt model highlighted that future temperature increases coupled with reduced precipitation would lead to significant reductions in the suitable habitats of the species in northern Ethiopia. The species' suitable habitats were predicted to decline by 48–83% for D. ombet and 35–87% for D. glabra. Hence, to sustain the species populations, different strategies should be adopted, namely the introduction of alternative livelihoods (e.g., gathering NTFP) to reduce the overexploitation of the species for subsistence income and the protection of the current habitats that will remain suitable in the future using community-based exclosures. Additionally, the preservation of the species' seeds in gene banks is crucial to ensure their long-term conservation.

Keywords: grazing lands, hillside areas, land-use change, MaxEnt, range limitation, rare and endangered tree species

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Authors: Amandeep Singh, Niraj Bala

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In the last decades, light-weight materials such as magnesium matrix composites have become hot topic for material research due to their excellent mechanical and physical properties. However, relatively very less work has been done related to the wear behavior of these composites. Magnesium matrix composites have wide applications in automobile and aerospace sector. In this review, attempt has been done to collect the literature related to wear behavior of magnesium matrix composites fabricated through various processing techniques such as stir casting, powder metallurgy, friction stir processing etc. Effect of different reinforcements, reinforcement content, reinforcement size, wear load, sliding speed and time have been studied by different researchers in detail. Wear mechanism under different experimental condition has been reviewed in detail. The wear resistance of magnesium and its alloys can be enhanced with the addition of different reinforcements. Wear resistance can further be enhanced by increasing the percentage of added reinforcements. Increase in applied load during wear test leads to increase in wear rate of magnesium composites.

Keywords: hardness, magnesium matrix composites, reinforcement, wear

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Authors: Xiaoyu Shen, Fang Fang, Chujun Qiu

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Herewith we present a Fourier method for credit risk quantification and allocation in the factor-copula model framework. The key insight is that, compared to directly computing the cumulative distribution function of the portfolio loss via Monte Carlo simulation, it is, in fact, more efficient to calculate the transformation of the distribution function in the Fourier domain instead and inverting back to the real domain can be done in just one step and semi-analytically, thanks to the popular COS method (with some adjustments). We also show that the Euler risk allocation problem can be solved in the same way since it can be transformed into the problem of evaluating a conditional cumulative distribution function. Once the conditional or unconditional cumulative distribution function is known, one can easily calculate various risk metrics. The proposed method not only fills the niche in literature, to the best of our knowledge, of accurate numerical methods for risk allocation but may also serve as a much faster alternative to the Monte Carlo simulation method for risk quantification in general. It can cope with various factor-copula model choices, which we demonstrate via examples of a two-factor Gaussian copula and a two-factor Gaussian-t hybrid copula. The fast error convergence is proved mathematically and then verified by numerical experiments, in which Value-at-Risk, Expected Shortfall, and conditional Expected Shortfall are taken as examples of commonly used risk metrics. The calculation speed and accuracy are tested to be significantly superior to the MC simulation for real-sized portfolios. The computational complexity is, by design, primarily driven by the number of factors instead of the number of obligors, as in the case of Monte Carlo simulation. The limitation of this method lies in the "curse of dimension" that is intrinsic to multi-dimensional numerical integration, which, however, can be relaxed with the help of dimension reduction techniques and/or parallel computing, as we will demonstrate in a separate paper. The potential application of this method has a wide range: from credit derivatives pricing to economic capital calculation of the banking book, default risk charge and incremental risk charge computation of the trading book, and even to other risk types than credit risk.

Keywords: credit portfolio, risk allocation, factor copula model, the COS method, Fourier method

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Authors: Zachary Huffman, Joana Rocha

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Wall-pressure fluctuations induced by the turbulent boundary layer (TBL) developed over aircraft are a significant source of aircraft cabin noise. Since the power spectral density (PSD) of these pressure fluctuations is directly correlated with the amount of sound radiated into the cabin, the development of accurate empirical models that predict the PSD has been an important ongoing research topic. The sound emitted can be represented from the pressure fluctuations term in the Reynoldsaveraged Navier-Stokes equations (RANS). Therefore, early TBL empirical models (including those from Lowson, Robertson, Chase, and Howe) were primarily derived by simplifying and solving the RANS for pressure fluctuation and adding appropriate scales. Most subsequent models (including Goody, Efimtsov, Laganelli, Smol’yakov, and Rackl and Weston models) were derived by making modifications to these early models or by physical principles. Overall, these models have had varying levels of accuracy, but, in general, they are most accurate under the specific Reynolds and Mach numbers they were developed for, while being less accurate under other flow conditions. Despite this, recent research into the possibility of using alternative methods for deriving the models has been rather limited. More recent studies have demonstrated that an artificial neural network model was more accurate than traditional models and could be applied more generally, but the accuracy of other machine learning techniques has not been explored. In the current study, an original model is derived using a stepwise regression algorithm in the statistical programming language R, and TBL wall-pressure fluctuations PSD data gathered at the Carleton University wind tunnel. The theoretical advantage of a stepwise regression approach is that it will automatically filter out redundant or uncorrelated input variables (through the process of feature selection), and it is computationally faster than machine learning. The main disadvantage is the potential risk of overfitting. The accuracy of the developed model is assessed by comparing it to independently sourced datasets.

Keywords: aircraft noise, machine learning, power spectral density models, regression models, turbulent boundary layer wall-pressure fluctuations

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Authors: P. M. Keshtiban, M. Zdshakoyan, G. Faragi

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Different severe plastic deformation (SPD) methods are the most successful ways to build nano-structural materials from coarse grain samples without changing the cross-sectional area. One of the most widely used methods in the SPD process is equal channel angler pressing (ECAP). In this paper, ECAP process on Al1050 sheets was evaluated at room temperature by both experiments and finite element method. Since, one of the main objectives of SPD processes is to achieve high equivalent plastic strain (PEEQ) in one cycle, the values of PEEQ obtained by finite element simulation. Also, force-displacement curve achieved by FEM. To study the changes of mechanical properties, micro-hardness tests were conducted on samples and improvement in the mechanical properties were investigated. Results show that there is the good proportion between FEM, theory and experimental results.

Keywords: AL1050, experiments, finite element method, severe plastic deformation

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Authors: Juliana Bastos dos Santos, Francisca Dantas Mendes, Abdul Jabbar Mohammad Khatri, Adam Abdul Jabbar Khatri

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This research aims to describe the experimentation of color extraction from household waste, for the application of the natural vegetable dyeing technique, as a more sustainable option for the upcycling process. Based on the research of the case study, this article intends to record the process of collecting the materials, extracting the colors and their applicability. The study aims to deepen the knowledge about possible alternatives that generate less impact on the environment throughout the process of plant stamping and, also, to spread the concepts of sustainability in fashion. Therefore, this content becomes relevant for valuing an artisanal production process, reconnecting with ancestral knowledge. This article also intends to serve as a record of ancestral artisanal processes, based on the indigenous and African matrices that are pillars of Brazilian culture.

Keywords: natural dyeing, sustainability, organic residue, fashion, reuse

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Authors: Bounar Nedjemeddine

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Materials with the pyrochlore lattice structure have attracted much recent attention due to their wide applications in ceramic thermal barrier coatings, high-permittivity dielectrics, and potential solid electrolytes in solid-oxide fuel cells. The work described in this paper is devoted to the synthesis and characterization of a pyrochlore structure based on lanthanum (La₂O₃) and tin (SnO₂) oxides of general formula La₂Sn₂O₇, substituted by Sr at the site La. Their structures were determined from X-ray powder diffraction using CELFER analysis. All the compositions present the space group Fd-3m. The substitution of La by Sr in the La₂Sn₂O₇ compound causes a variation of the cell parameters. The difference in charge between La³⁺ and Sr²⁺ and the difference in size cause the cell parameters to decrease from a=10.7165 A° to a=10.6848 A° for the substitution rates (x = 0.05, 0.1, 0.15 ...), which leads to a decrease in the volume of the mesh. For a substitution rate x = 0.25, there is an increase in the cell parameters (a=10.7035A°), which can be explained by a competitiveness of the size effect and the presence of a gap in the structure which go in the opposite direction.

Keywords: solid-oxide fuel cells, structure, pyrochlore, X-ray diffraction

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Authors: Valeria Corinaldesi

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In general, for self-compacting concrete production, a high volume of very fine materials is necessary in order to make the concrete more fluid and cohesive. For this purpose, either rubble powder (which is a powder obtained from suitable treatment of rubble from building demolition) or ash from municipal solid waste incineration was used as mineral addition in order to ensure adequate rheological properties of the self-compacting concrete in the absence of any viscosity modifying admixture. Recycled instead of natural aggregates were used by completely substituting the coarse aggregate fraction. The fresh concrete properties were evaluated through the slump flow, the V-funnel and the L-box test. Compressive strength and segregation resistance were also determined. The results obtained showed that self-compacting concrete could be successfully developed by incorporating both recycled aggregates and waste powders with an improved quality of the concrete surface finishing. This encouraging goal, beyond technical performance, matches with the more and more widely accepted sustainable development issues.

Keywords: sustainable concrete, self compacting concrete, municipal solid waste, recycled aggregate, sustainable building

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Authors: Aleya Ferdausi, Meriel Jones, Anthony Halls

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The Amaryllidaceae genus Narcissus contains secondary metabolites, which are important sources of bioactive compounds such as pharmaceuticals indicating that their biological activity extends from the native plant to humans. Transcriptome analysis (RNA-seq) is an effective platform for the identification and functional characterization of candidate genes as well as to identify genes encoding uncharacterized enzymes. The biotechnological production of secondary metabolites in plant cell or organ cultures has become a tempting alternative to the extraction of whole plant material. The biochemical pathways for the production of secondary metabolites require primary metabolites to undergo a series of modifications catalyzed by enzymes such as cytochrome P450s, methyltransferases, glycosyltransferases, and acyltransferases. Differential gene expression analysis of Narcissus was obtained from two conditions, i.e. field and in vitro callus. Callus was obtained from modified MS (Murashige and Skoog) media supplemented with growth regulators and twin-scale explants from Narcissus cv. Carlton bulb. A total of 2153 differentially expressed transcripts were detected in Narcissus bulb and in vitro callus, and 78.95% of those were annotated. It showed the expression of genes involved in the biosynthesis of alkaloids were present in both conditions i.e. cytochrome P450s, O-methyltransferase (OMTs), NADP/NADPH dehydrogenases or reductases, SAM-synthetases or decarboxylases, 3-ketoacyl-CoA, acyl-CoA, cinnamoyl-CoA, cinnamate 4-hydroxylase, alcohol dehydrogenase, caffeic acid, N-methyltransferase, and NADPH-cytochrome P450s. However, cytochrome P450s and OMTs involved in the later stage of Amaryllidaceae alkaloids biosynthesis were mainly up-regulated in field samples. Whereas, the enzymes involved in initial biosynthetic pathways i.e. fructose biphosphate adolase, aminotransferases, dehydrogenases, hydroxyl methyl glutarate and glutamate synthase leading to the biosynthesis of precursors; tyrosine, phenylalanine and tryptophan for secondary metabolites were up-regulated in callus. The knowledge of probable genes involved in secondary metabolism and their regulation in different tissues will provide insight into the Narcissus plant biology related to alkaloid production.

Keywords: narcissus, callus, transcriptomics, secondary metabolites

Procedia PDF Downloads 140

Authors: Vinay Singh, Chandra Deo, Asit Chakrabarti, Lopamudra Sahoo, Mahak Singh, Rakesh Kumar, Dinesh Kumar, H. Bharati, Biswajit Das, V. K. Mishra

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The most widely used feed resources in poultry feed, like maize and soybean, are expensive as well as in short supply. Hence, there is a need to utilize non-conventional feed ingredients to cut down feed costs. As an alternative, brewery by-products like brewers’ dried grains are potential non-conventional feed resources. North-East India is inhabited by many tribes, and most of these tribes prepare their indigenous local brew, mostly using rice grains as the primary substrate. Choak, a homemade rice beer waste, is an excellent and cheap source of protein and other nutrients. Fresh homemade rice beer waste (rice brewer’s grain) was collected locally. The proximate analysis indicated 28.53% crude protein, 92.76% dry matter, 5.02% ether extract, 7.83% crude fibre, 2.85% total ash, 0.67% acid insoluble ash, 0.91% calcium, and 0.55% total phosphorus. A feeding trial with 5 treatments (incorporating rice beer waste at the inclusion levels of 0,10,20,30 & 40% by replacing maize and soybean from basal diet) was conducted with 25 laying hens per treatment for 16 weeks under completely randomized design in order to study the production performance, blood-biochemical parameters, immunity, egg quality and cost economics of laying hens. The results showed substantial variations (P<0.01) in egg production, egg mass, FCR per dozen eggs, FCR per kg egg mass, and net FCR. However, there was not a substantial difference in either body weight or feed intake or in egg weight. Total serum cholesterol reduced significantly (P<0.01) at 40% inclusion of rice beer waste. Additionally, the egg haugh unit grew considerably (P<0.01) when the graded levels of rice beer waste increased. The inclusion of 20% rice brewers dried grain reduced feed cost per kg egg mass and per dozen egg production by Rs. 15.97 and 9.99, respectively. Choak (homemade rice beer waste) can thus be safely incorporated into the diet of laying hens at a 20% inclusion level for better production performance and cost-effectiveness.

Keywords: choak, rice beer waste, laying hen, production performance, cost economics

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Authors: Anuschka Curran, Sandra Barnard

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Coral reefs are of the most diverse and productive ecosystems on the planet, but due to the impact of climate change, these infrastructures are dying off primarily through coral bleaching. Coral bleaching can be described as the process by which zooxanthellae (algal endosymbionts) are expelled from the gastrodermal cavity of the respective coral host, causing increased coral whitening. The general consensus is that mass coral bleaching is due to the dysfunction of photosynthetic processes in the zooxanthellae as a result of the combined action of elevated temperature and light-stress. The question then is, do zooxanthellae have the potential to play a key role in the future of coral reef restoration through genetic engineering? The aim of this study is firstly to review the different zooxanthellae taxa and their traits with respect to environmental stress, and secondly, to review the information available on the protective mechanisms present in zooxanthellae cells when experiencing temperature fluctuations, specifically concentrating on heat shock proteins and the antioxidant stress response of zooxanthellae. The eight clades (A-H) previously recognized were redefined into seven genera. Different zooxanthellae taxa exhibit different traits, such as their photosynthetic stress responses to light and temperature. Zooxanthellae have the ability to determine the amount and type of heat shock proteins (hsps) present during a heat response. The zooxanthellae can regulate both the host’s respective hsps as well as their own. Hsps, generally found in genotype C3 zooxanthellae, such as Hsp70 and Hsp90, contribute to the thermal stress response of the respective coral host. Antioxidant activity found both within exposed coral tissue, and the zooxanthellae cells can prevent coral hosts from expelling their endosymbionts. The up-regulation of gene expression, which may mitigate thermal stress induction of any of the physiological aspects discussed, can ensure stable coral-zooxanthellae symbiosis in the future. It presents a viable alternative strategy to preserve reefs amidst climate change. In conclusion, despite their unusual molecular design, genetic engineering poses as a useful tool in understanding and manipulating variables and systems within zooxanthellae and therefore presents a solution that can ensure stable coral-zooxanthellae symbiosis in the future.

Keywords: antioxidant enzymes, genetic engineering, heat-shock proteins, Symbiodinium

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Authors: Goksen Capar, Levent Dogankaya

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According to the circular economy model, resource productivity should be maximized and wastes should be reduced. Since earth’s natural resources are continuously depleted, resource recovery has gained great interest in recent years. As part of our research study on the recovery and reuse of silk wastes, this paper focuses on the utilization of silkworm pupae as fishmeal replacement, which would replace the original fishmeal raw material, namely the fish itself. This, in turn, would contribute to sustainable management of wild fish resources. Silk fibre is secreted by the silkworm Bombyx mori in order to construct a 'room' for itself during its transformation process from pupae to an adult moth. When the cocoons are boiled in hot water, silk fibre becomes loose and the silk yarn is produced by combining thin silk fibres. The remaining wastes are 1) sericin protein, which is dissolved in water, 2) remaining part of cocoon, including the dead body of B. mori pupae. In this study, an eight weeks trial was carried out to determine the growth performance of common carp juveniles fed with waste silkworm pupae meal (SWPM) as a replacement for fishmeal (FM). Four isonitrogenous diets (40% CP) were prepared replacing 0%, 33%, 50%, and 100% of the dietary FM with non-defatted silkworm pupae meal as a dietary protein source for experiments in C. carpio. Triplicate groups comprising of 20 fish (0.92±0.29 g) were fed twice/day with one of the four diets. Over a period of 8 weeks, results showed that the diet containing 50% of its protein from SWPM had significantly higher (p ≤ 0.05) growth rates in all groups. The increasing levels of SWPM were resulted in a decrease in growth performance and significantly lower growth (p ≤ 0.05) was observed with diets having 100% SWPM. The study demonstrates that it is practical to replace 50% of the FM protein with SWPM with a significantly better utilization of the diet but higher SWPM levels are not recommended for juvenile carp. Further experiments are under study to have more detailed results on the possible effects of this alternative diet on the growth performance of juvenile carp.

Keywords: Bombyx mori, Cyprinus carpio, fish meal, silk, waste pupae

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Authors: Violina R. Angelova, Mariana N. Perifanova-Nemska, Galina P. Uzunova, Elitsa N. Kolentsova

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Comparative research has been conducted to allow us to determine the accumulation of heavy metals (Pb, Zn and Cd) in the vegetative and reproductive organs of safflower, and to identify the possibility of its growth on soils contaminated by heavy metals and efficacy for phytoremediation. The experiment was performed on an agricultural field contaminated by the Non-Ferrous-Metal Works (MFMW) near Plovdiv, Bulgaria. The experimental plots were situated at different distances (0.1, 0.5, 2.0, and 15 km) from the source of pollution. The contents of heavy metals in plant materials (roots, stems, leaves, seeds) were determined. The quality of safflower oils (heavy metals and fatty acid composition) was also determined. The quantitative measurements were carried out with inductively-coupled plasma (ICP). Safflower is a plant that is tolerant to heavy metals and can be referred to the hyperaccumulators of lead and cadmium and the accumulators of zinc. The plant can be successfully used in the phytoremediation of heavy metal contaminated soils. The processing of safflower seeds into oil and the use of the obtained oil will greatly reduce the cost of phytoremediation.

Keywords: heavy metals, accumulation, safflower, polluted soils, phytoremediation

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Authors: Cristina Diaz, Lucia Perez, Simone Visigalli, Giuseppe Di Florio, Gonzalo Fuentes, Roberto Canziani, Paolo Gronchi

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During the last 50 years, the selection of materials is one of the main decisions in machine design for different industrial applications. It is due to numerous physical, chemical, mechanical and technological factors to consider in it. Corrosion effects are related with all of these factors and impact in the life cycle, machine incidences and the costs for the life of the machine. Corrosion affects the deterioration or destruction of metals due to the reaction with the environment, generally wet. In food industry, dewatering industry, concrete industry, paper industry, etc. corrosion is an unsolved problem and it might introduce some alterations of some characteristics in the final product. Nowadays, depending on the selected metal, its surface and its environment of work, corrosion prevention might be a change of metal, use a coating, cathodic protection, use of corrosion inhibitors, etc. In the vast majority of the situations, use of a corrosion resistant material or in its defect, a corrosion protection coating is the solution. Stainless steels are widely used in machine design, because of their strength, easily cleaned capacity, corrosion resistance and appearance. Typical used are AISI 304 and AISI 316. However, their benefits don’t fit every application, and some coatings are required against corrosion such as some paintings, galvanizing, chrome plating, SiO₂, TiO₂ or ZrO₂ coatings, etc. In this work, some coatings based in a bilayer made of Titanium-Tantalum, Titanium-Niobium, Titanium-Hafnium or Titanium-Zirconium, have been developed used magnetron sputtering configuration by PVD (Physical Vapor Deposition) technology, for trying to reduce corrosion effects on AISI 304, AISI 316 and comparing it with Titanium alloy substrates. Ti alloy display exceptional corrosion resistance to chlorides, sour and oxidising acidic media and seawater. In this study, Ti alloy (99%) has been included for comparison with coated AISI 304 and AISI 316 stainless steel. Corrosion tests were conducted by a Gamry Instrument under ASTM G5-94 standard, using different electrolytes such as tomato salsa, wine, olive oil, wet compost, a mix of sand and concrete with water and NaCl for testing corrosion in different industrial environments. In general, in all tested environments, the results showed an improvement of corrosion resistance of all coated AISI 304 and AISI 316 stainless steel substrates when they were compared to uncoated stainless steel substrates. After that, comparing these results with corrosion studies on uncoated Ti alloy substrate, it was observed that in some cases, coated stainless steel substrates, reached similar current density that uncoated Ti alloy. Moreover, Titanium-Zirconium and Titanium-Tantalum coatings showed for all substrates in study including coated Ti alloy substrates, a reduction in current density more than two order in magnitude. As conclusion, Ti-Ta, Ti-Zr, Ti-Nb and Ti-Hf coatings have been developed for improving corrosion resistance of AISI 304 and AISI 316 materials. After corrosion tests in several industry environments, substrates have shown improvements on corrosion resistance. Similar processes have been carried out in Ti alloy (99%) substrates. Coated AISI 304 and AISI 316 stainless steel, might reach similar corrosion protection on the surface than uncoated Ti alloy (99%). Moreover, coated Ti Alloy (99%) might increase its corrosion resistance using these coatings.

Keywords: coatings, corrosion, PVD, stainless steel

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Authors: Fatemeh Karimi

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The fashion and textile industry is undergoing a profound transformation, with polymers playing an increasingly pivotal role in driving innovation and sustainability. This paper explores the application of polymers in fashion and textile engineering, focusing on their impact on material properties, sustainability, and the future of garment production. Polymers, both synthetic and bio-based, offer unique opportunities to enhance the performance, durability, and environmental footprint of textiles. By examining recent advancements in polymer science and their integration into fashion design and production, we provide insights into how these materials are reshaping the industry. This paper also discusses the challenges and opportunities associated with the use of polymers, particularly in the context of sustainable fashion and circular economy practices. Through case studies and industry examples, we highlight the innovative ways in which polymers are being utilized to meet the evolving demands of consumers and the industry's sustainability goals.

Keywords: polymer textiles, sustainable fashion, bio-based polymers, smart textiles, fashion innovation, circular economy, textile engineering

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Authors: Gabriela D. Silva, Rodrigo L. O. R. Cunha, Mauricio D. Coutinho-Neto

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In the last four decades the biological activities of selenium compounds has received great attention, particularly for hypervalent derivates from selenium (IV) used as enzyme inhibitors. The unregulated activity of cysteine proteases are related to the development of several pathologies, such as neurological disorders, cardiovascular diseases, obesity, rheumatoid arthritis, cancer and parasitic infections. These enzymes are therefore a valuable target for designing new small molecule inhibitors such as selenuranes. Even tough there has been advances in the synthesis and design of new selenuranes based inhibitors, little is known about their mechanism of action. It is a given that inhibition occurs through the reaction between the thiol group of the enzyme and the chalcogen atom. However, several open questions remain about the nature of the mechanism (associative vs. dissociative) and about the nature of the reactive species in solution under physiological conditions. In this work we performed a theoretical investigation on model systems to study the possible routes of substitution reactions. Nucleophiles may be present in biological systems, our interest is centered in the thiol groups from the cysteine proteases and the hydroxyls from the aqueous environment. We therefore expect this study to clarify the possibility of a route reaction in two stages, the first consisting of the substitution of chloro atoms by hydroxyl groups and then replacing these hydroxyl groups per thiol groups in selenuranes. The structures of selenuranes and nucleophiles were optimized using density function theory along the B3LYP functional and a 6-311+G(d) basis set. Solvent was treated using the IEFPCM method as implemented in the Gaussian 09 code. Our results indicate that hydrolysis from water react preferably with selenuranes, and then, they are replaced by the thiol group. It show the energy values of -106,0730423 kcal/mol for dople substituition by hydroxyl group and 96,63078511 kcal/mol for thiol group. The solvatation and pH reduction promotes this route, increasing the energy value for reaction with hydroxil group to -50,75637672 kcal/mol and decreasing the energy value for thiol to 7,917767189 kcal/mol. Alternative ways were analyzed for monosubstitution (considering the competition between Cl, OH and SH groups) and they suggest the same route. Similar results were obtained for aliphatic and aromatic selenuranes studied.

Keywords: chalcogenes, computational study, cysteine proteases, enzyme inhibitors

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Authors: Sideri Katerina, Chanania Eleni

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The reasons why people remain unvaccinated, especially health workers, are complex. In Greece, 2 percent of health workers (around 7,000) remain unvaccinated, despite the fact that for this group of people vaccination against COVID-19 is mandatory. In April 2022, the Greek health minister repeated that unvaccinated health care workers will remain suspended from their jobs ‘for as long as the pandemic lasts,’ explaining that the suspension of the workers in question was ‘entirely their choice’ and that health professionals who do not believe in vaccines ‘do not believe in their own science.’ Although policy circles around the world often link vaccine hesitancy to ignorance of science or misinformation, various recently published qualitative studies show that vaccine hesitancy is the result of a combination of factors, which include distrust towards elites and the system of innovation and distrust towards government. In a similar spirit, some commentators warn that labeling hesitancy as “anti-science” is bad politics. In this paper, we worked within the tradition of STS taking the view that people draw upon personal associations to enact and express civic concern with an issue, the enactment of public concern involves the articulation of threats to actors’ way of life, personal values, relationships, lived experiences, broader societal values and institutional structures. To this effect, we have conducted 27 in depth interviews with unvaccinated Greek health workers and we are in the process of conducting 20 more interviews. We have so far found that rather than a question of believing in ‘facts’ vaccine hesitancy reflects deep distrust towards those charged with the making of decisions and pharmaceutical companies and that emotions (rather than rational thinking) play a crucial role in the formation of attitudes and the making of decisions. We need to dig deeper so as to understand the causes of distrust towards technical government and the ways in which public(s) conceive of and want to be part in the politics of innovation. We particularly address the question of the effectiveness of mandatory vaccination of health workers and whether such top-down regulatory measures further polarize society, to finally discuss alternative regulatory approaches and governance structures.

Keywords: vaccine hesitancy, innovation, trust in vaccines, sociology of vaccines, attitude drivers towards scientific information, governance

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Authors: A. J. Shah, Neeraj Kumar Sahu

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Reactive powder concrete (RPC) is high performance and high strength concrete which composes of very fine powdered materials like cement, sand, silica fume and quartz powder. It also constitutes steel fibre (optional) and super-plasticizer. The present study investigates the performance of reactive powder concrete with fly ash as a replacement of cement under hot water and normal water curing conditions. The replacement of cement with fly ash is done at 10%, 20%, 30% and 40%. To compare the results of cement replaced RPC and traditional RPC, the performance of various mixes is evaluated by compressive strength, flexural strength, split tensile strength and durability. The results show that with increasing percentage of fly ash, improvement in durability is observed and a slight decrease in compressive strength and flexural strength is also observed. It is observed that specimen under hot water curing showed 15 to 20 % more strength than specimens under normal water curing.

Keywords: high strength concrete, the flexural strength of RPC, compressive strength of RPC, durability

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Authors: Muhammad Shahzad Shifa, Amna Shifa, Muhammad Omar, Aamir Shahzad, Rahmat Ali Khan

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Many applications of remote sensing to vegetation and crop response depend on spectral properties of individual leaves and plants. Vegetation indices are usually determined to estimate crop biophysical parameters like crop canopies and crop leaf area indices with the help of remote sensing. Cotton crops assessment is performed with the help of vegetative indices. Remotely sensed images from an optical multispectral radiometer MSR5 are used in this study. The interpretation is based on the fact that different materials reflect and absorb light differently at different wavelengths. Non-normalized and normalized forms of these datasets are analyzed using two complementary data mining algorithms; K-means and K-nearest neighbor (KNN). Our analysis shows that the use of normalized reflectance data and vegetative indices are suitable for an automated assessment and decision making.

Keywords: cotton, condition assessment, KNN algorithm, clustering, MSR5, vegetation indices

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Authors: Chidiebere Samuel Ijeoma

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The impact and importance of technology in all domains of existence cannot be overemphasized. It is like a double-edged sword which can be both constructive and destructive. The paper, therefore, tends to evaluate the impact of technology so far in the teaching and learning of French language in Nigeria. According to the study, the traditional methods of teaching French as a Foreign Language and recognized as our cultural methods of knowledge transfer are being fast replaced by digitalization in teaching. This, the research tends to portray and suggest the best way forward. In the Nigerian Primary Education System, the use of some local and cultural Instructional materials (teaching aids) is now almost history which the paper frowns at. Consequently, the study has these questions to ask?; Where are the chalks and blackboards? Where are the ‘Handworks’ (local brooms) submitted by school children as part of their Continuous Assessment? Finally, the research is in no way against the application of technology in the Nigerian French Language Teaching System but tries to draw a curtain between Technological methods of teaching French as a Foreign Language and the Original Nigerian System of teaching the language before the arrival of technology.

Keywords: French language teaching, future, impact, importance of technology

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Authors: M. Simchi, M. Amiri, E. Rezvani, I. Mirzaei, M. Berahman, A. Simchi, M. Fardmanesh

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Graphene is a single-atomic two-dimensional crystal of carbon atoms that has considerable properties due to its unique structure and physics with applications in different fields. Graphene has sensitive electrical properties due to its atomic-thin structure. Along with the substrate materials and their influence on the transport properties in graphene, design and fabrication of graphene-based devices for biomedical and biosensor applications are challenging. In this work, large-area high-quality graphene nanosheets were prepared by low pressure chemical vapor deposition using methane gas as carbon source on copper foil and transferred on the biocompatible substrates. Through deposition of titanium and gold contacts, current-voltage response of the transferred graphene on four biocompatible substrates, including PDMS, SU-8, Nitrocellulose, and Kapton (Fig. 2) were experimentally determined. The considerable effect of the substrate type on the electrical properties of graphene is shown. The sheet resistance of graphene is changed from 0.34 to 14.5 kΩ/sq, depending on the substrate.

Keywords: biocompatible substrates, electrical properties, graphene, sheet resistance

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Authors: A. Odoom, A. Salama, H. Ibrahim

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Hydrogen is a clean source of energy for power production and transportation. The main source of hydrogen in this research is biodiesel. Glycerol also called glycerine is a by-product of biodiesel production by transesterification of vegetable oils and methanol. This is a reliable and environmentally-friendly source of hydrogen production than fossil fuels. A typical composition of crude glycerol comprises of glycerol, water, organic and inorganic salts, soap, methanol and small amounts of glycerides. Crude glycerol has limited industrial application due to its low purity thus, the usage of crude glycerol can significantly enhance the sustainability and production of biodiesel. Reforming techniques is an approach for hydrogen production mainly Steam Reforming (SR), Autothermal Reforming (ATR) and Partial Oxidation Reforming (POR). SR produces high hydrogen conversions and yield but is highly endothermic whereas POR is exothermic. On the downside, PO yields lower hydrogen as well as large amount of side reactions. ATR which is a fusion of partial oxidation reforming and steam reforming is thermally neutral because net reactor heat duty is zero. It has relatively high hydrogen yield, selectivity as well as limits coke formation. The complex chemical processes that take place during the production phases makes it relatively difficult to construct a reliable and robust numerical model. Numerical model is a tool to mimic reality and provide insight into the influence of the parameters. In this work, we introduce a finite volume numerical study for an 'in-house' lab-scale experiment of ATR. Previous numerical studies on this process have considered either using Comsol or nodal finite difference analysis. Since Comsol is a commercial package which is not readily available everywhere and lab-scale experiment can be considered well mixed in the radial direction. One spatial dimension suffices to capture the essential feature of ATR, in this work, we consider developing our own numerical approach using MATLAB. A continuum fixed bed reactor is modelled using MATLAB with both pseudo homogeneous and heterogeneous models. The drawback of nodal finite difference formulation is that it is not locally conservative which means that materials and momenta can be generated inside the domain as an artifact of the discretization. Control volume, on the other hand, is locally conservative and suites very well problems where materials are generated and consumed inside the domain. In this work, species mass balance, Darcy’s equation and energy equations are solved using operator splitting technique. Therefore, diffusion-like terms are discretized implicitly while advection-like terms are discretized explicitly. An upwind scheme is adapted for the advection term to ensure accuracy and positivity. Comparisons with the experimental data show very good agreements which build confidence in our modeling approach. The models obtained were validated and optimized for better results.

Keywords: autothermal reforming, crude glycerol, hydrogen, numerical model

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Authors: Florian Misoc, Cyril Okhio, Joshua Tolbert, Nick Carlin, Thomas Ramey

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This project is focused on designing a Stirling engine system for a solar-thermal-electrical system that can supply electric power to a single residential unit. Since Stirling engines are heat engines operating any available heat source, is notable for its ability to generate clean and reliable energy without emissions. Due to the need of finding alternative energy sources, the Stirling engines are making a comeback with the recent technologies, which include thermal energy conservation during the heat transfer process. Recent reviews show mounting evidence and positive test results that Stirling engines are able to produce constant energy supply that ranges from 5kW to 20kW. Solar Power source is one of the many uses for Stirling engines. Using solar energy to operate Stirling engines is an idea considered by many researchers, due to the ease of adaptability of the Stirling engine. In this project, the Stirling engine developed was designed and tested to operate from biomass source of energy, i.e., wood pellets stove, during low solar radiation, with good results. A 20% efficiency of the engine was estimated, and 18% efficiency was measured, making it suitable and appropriate for residential applications. The effort reported was aimed at exploring parameters necessary to design, build and test a ‘Solar Powered Stirling Engine (SPSE)’ using Water (H₂O) as the Heat Transfer medium, with Nitrogen as the working gas that can reach or exceed an efficiency of 20%. The main objectives of this work consisted in: converting a V-twin cylinder air compressor into an alpha-type Stirling engine, construct a Solar Water Heater, by using an automotive radiator as the high-temperature reservoir for the Stirling engine, and an array of fixed mirrors that concentrate the solar radiation on the automotive radiator/high-temperature reservoir. The low-temperature reservoir is the surrounding air at ambient temperature. This work has determined that a low-cost system is sufficiently efficient and reliable. Off-the-shelf components have been used and estimates of the ability of the Engine final design to meet the electricity needs of small residence have been determined.

Keywords: stirling engine, solar-thermal, power inverter, alternator

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Authors: Sunday B. Alabi, Edikan P. Felix, Aniediong M. Umo

Abstract:

Crystal size distribution is of great importance in the sugar factories. It determines the market value of granulated sugar and also influences the cost of production of sugar crystals. Typically, sugar is produced using fed-batch vacuum evaporative crystallizer. The crystallization quality is examined by crystal size distribution at the end of the process which is quantified by two parameters: the average crystal size of the distribution in the mean aperture (MA) and the width of the distribution of the coefficient of variation (CV). Lack of real-time measurement of the sugar crystal size hinders its feedback control and eventual optimisation of the crystallization process. An attractive alternative is to use a soft sensor (model-based method) for online estimation of the sugar crystal size. Unfortunately, the available models for sugar crystallization process are not suitable as they do not contain variables that can be measured easily online. The main contribution of this paper is the development of a regression model for estimating the sugar crystal size as a function of input variables which are easy to measure online. This has the potential to provide real-time estimates of crystal size for its effective feedback control. Using 7 input variables namely: initial crystal size (Lo), temperature (T), vacuum pressure (P), feed flowrate (Ff), steam flowrate (Fs), initial super-saturation (S0) and crystallization time (t), preliminary studies were carried out using Minitab 14 statistical software. Based on the existing sugar crystallizer models, and the typical ranges of these 7 input variables, 128 datasets were obtained from a 2-level factorial experimental design. These datasets were used to obtain a simple but online-implementable 6-input crystal size model. It seems the initial crystal size (Lₒ) does not play a significant role. The goodness of the resulting regression model was evaluated. The coefficient of determination, R² was obtained as 0.994, and the maximum absolute relative error (MARE) was obtained as 4.6%. The high R² (~1.0) and the reasonably low MARE values are an indication that the model is able to predict sugar crystal size accurately as a function of the 6 easy-to-measure online variables. Thus, the model can be used as a soft sensor to provide real-time estimates of sugar crystal size during sugar crystallization process in a fed-batch vacuum evaporative crystallizer.

Keywords: crystal size, regression model, soft sensor, sugar, vacuum evaporative crystallizer

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Authors: M. Fares, S. Mameri, I. Abdlani, K. Negara

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Neutron detectors in general, proportional counters gas filling based isotope 3He in particular are going to be essential for monitoring and control of certain nuclear facilities, monitoring of experimentation around neutron beams and channels nuclear research reactors, radiation protection instruments and other tools multifaceted exploration and testing of materials, etc. This work consists of a measurement campaign features two Proportional Counters 3He (3He: LND252/USA CP, CP prototype: 3He LND/DDM). This is to make a comparison study of a CP 3He LND252/USA reference one hand, and in the context of routine periodic monitoring of the characteristics of the detectors for controlling the operation especially for laboratory prototypes. In this paper, we have described the different characteristics of the detectors and the experimental protocols used. Tables of measures have been developed and the different curves were plotted. The experimental campaign at stake: 2 PC 3He were thus characterized: Their characteristics (sensitivity, energy pulse height distribution spectra, gas amplification etc.) Were identified: 01 PC 3He 1'' Type: prototype DEDIN/DDM, 01 PC 3He 1'' Type: LND252/USA.

Keywords: PC 3He, sensitivity, pulse height distribution spectra, gas amplification

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Authors: Babak Nematshahrbabaki, Fallahi Arezoo

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Objective: The aim of this study was to describe teenagers’ decisions to undergo orthodontic treatment through a qualitative study. Materials and methods: Twenty-three patients (12 girls), aged 12–18 years, at a dental clinic in Sanandaj the western part of Iran participated. Face-to-face and semi-structured interviews and two focus group discussions were held to gather data. Data analyzed by the grounded theory method. Results: ‘Decision-making’ was the core category. During the data analysis four main themes were developed: ‘being like everyone else’, ‘being diagnosed’, ‘maintaining the mouth’ and ‘cultural-social and environmental factors’. Conclusions: cultural- social and environmental factors have crucial role in decision-making to undergo orthodontic treatment. The teenagers were not fully conscious of these external influences. They thought their decision to undergo orthodontic treatment is independent while it is related to cultural- social and environmental factors.

Keywords: decision-making, qualitative study, teenager, orthodontic treatment

Procedia PDF Downloads 444

Authors: David W. Taylor, Fernando Lourenço, Carolyn Branston, Paul Tucker

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There are an increasing number of students at Universities in the United Kingdom engaging in entrepreneurship role-play to explore business start-up as a career alternative to employment. These role-play activities have been shown to have a positive influence on students’ entrepreneurial intentions. Universities also play a role in developing graduates’ awareness of social responsibility. However, social responsibility is often missing from these entrepreneurship role-plays. It is important that these role-play activities include the development of values that support social responsibility, in-line with those running hybrid, humane and sustainable enterprises, and not simply focus on profit. The Young Enterprise (YE) Start-Up programme is an example of a role-play activity that is gaining in popularity amongst United Kingdom Universities seeking ways to give students insight into a business start-up. A Post-92 University in the North-West of England has adapted the traditional YE Directorship roles (e.g., Marketing Director, Sales Director) by including a Corporate Social Responsibility (CSR) Director in all of the team-based YE Start-Up businesses. The aim for introducing this Directorship was to observe if such a role would help create a more socially responsible value-system within each company and in turn shape business decisions. This paper investigates role-play as a tool to help enterprise educators develop socially responsible attitudes and values in nascent entrepreneurs. A mixed qualitative methodology approach has been used, which includes interviews, role-play, and reflection, to help students develop positive value characteristics through the exploration of unethical and selfish behaviors. The initial findings indicate that role-play helped CSR Directors learn and gain insights into the importance of corporate social responsibility, influenced the values and actions of their YE Start-Ups, and increased the likelihood that if the participants were to launch a business post-graduation, that the intent would be for the business to be socially responsible. These findings help inform educators on how to develop socially responsible nascent entrepreneurs within a traditionally profit orientated business model.

Keywords: student entrepreneurship, young enterprise, social responsibility, role-play, values

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Authors: Alvarado M. Lady G., Ortiz V. Yaylenne, Quintero B. Quelbis R.

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The oil palm sector has seen significant growth in Colombia after the insertion of policies to stimulate the use of biofuels, which eventually contributes to the reduction of greenhouse gases (GHG) that deteriorate not only the environment but the health of people. However, the policy of using biofuels has been strongly questioned by the impacts that can generate; an example is the increase of other more harmful GHGs like the CH₄ that underlies the amount of solid waste generated. Casanare's department is estimated be one of the major producers of palm oil of the country given that has recently expanded its sowed area, which implies an increase in waste generated primarily in the industrial stage. For this reason, the following study evaluated the agronomic potential of the biochar obtained from empty fruit bunches and its nutritional contribution in cultivated soils with Elaeis guineensis in Casanare, Colombia. The biochar was obtained by slow pyrolysis of the clusters in a retort oven at an average temperature of 190 °C and a residence time of 8 hours. The final product was taken to the laboratory for its physical and chemical analysis as well as a soil sample from a cultivation of Elaeis guineensis located in Tauramena-Casanare. With the results obtained plus the bibliographical reports of the nutrient demand in this cultivation, the possible nutritional contribution of the biochar was determined. It is estimated that the cultivation requirements of nitrogen is 12.1 kg.ha⁻¹, potassium is 59.3 kg.ha⁻¹, magnesium is -31.5 kg.ha⁻¹ and phosphorus is 5.6 kg.ha⁻¹ obtaining a biochar contribution of 143.1 kg.ha⁻¹, 1204.5 kg.ha⁻¹, 39.2 kg.ha⁻¹ and 71.6 kg.ha⁻¹ respectively. The incorporation of biochar into the soil would significantly improve the concentrations of N, P, K and Mg, nutrients considered important in the yield of palm oil, coupled with the importance of nutrient recycling in agricultural production systems sustainable. The biochar application improves the physical properties of soils, mainly in the humidity retention. On the other hand, it regulates the availability of nutrients for plants absorption, with economic savings in the application of synthetic fertilizers and water by irrigation. It also becomes an alternative to manage agricultural waste, reducing the involuntary emissions of greenhouse gases to the environment by decomposition in the field, reducing the CO₂ content in the atmosphere.

Keywords: biochar, nutrient recycling, oil palm, pyrolysis

Procedia PDF Downloads 151