Search results for: half metallic ferrimagnetism

Authors: Ye Zhang, Chuanjun Liu

Abstract:

In-service aircraft is exposed to different types of threaten, e.g. bird strike, ground vehicle impact, and run-way debris, or even lightning strike, etc. To satisfy the aircraft damage tolerance design requirements, the designer has to understand the threatening level for different types of the aircraft structures, either metallic or composite. Exposing to low-velocity impacts may produce very serious internal damages such as delaminations and matrix cracks without leaving visible mark onto the impacted surfaces for composite structures. This internal damage can cause significant reduction in the load carrying capacity of structures. The semi-probabilistic method provides a practical and proper approximation to establish the impact-threat based energy cut-off level for the damage tolerance evaluation of the aircraft components. Thus, the probabilistic distribution of impact threat and the realistic impact energy level cut-offs are the essential establishments required for the certification of aircraft composite structures. A new survey of impact threat to civil aircraft in-service has recently been carried out based on field records concerning around 500 civil aircrafts (mainly single aisles) and more than 4.8 million flight hours. In total 1,006 damages caused by low-velocity impact events had been screened out from more than 8,000 records including impact dents, scratches, corrosions, delaminations, cracks etc. The impact threat dependency on the location of the aircraft structures and structural configuration was analyzed. Although the survey was mainly focusing on the metallic structures, the resulting low-energy impact data are believed likely representative to general civil aircraft, since the service environments and the maintenance operations are independent of the materials of the structures. The probability of impact damage occurrence (Po) and impact energy exceedance (Pe) are the two key parameters for describing the statistic distribution of impact threat. With the impact damage events from the survey, Po can be estimated as 2.1x10-4 per flight hour. Concerning the calculation of Pe, a numerical model was developed using the commercial FEA software ABAQUS to backward estimate the impact energy based on the visible damage characteristics. The relationship between the visible dent depth and impact energy was established and validated by drop-weight impact experiments. Based on survey results, Pe was calculated and assumed having a log-linear relationship versus the impact energy. As the product of two aforementioned probabilities, Po and Pe, it is reasonable and conservative to assume Pa=PoxPe=10-5, which indicates that the low-velocity impact events are similarly likely as the Limit Load events. Combing Pa with two probabilities Po and Pe obtained based on the field survey, the cutoff level of realistic impact energy was estimated and valued as 34 J. In summary, a new survey was recently done on field records of civil aircraft to investigate the probabilistic distribution of impact threat. Based on the data, two probabilities, Po and Pe, were obtained. Considering a conservative assumption of Pa, the cutoff energy level for the realistic impact energy has been determined, which provides potential applicability in damage tolerance certification of future civil aircraft.

Keywords: composite structure, damage tolerance, impact threat, probabilistic

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Authors: Mohamed Akbi, Aissa Bouchou

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The present work aims to throw light on the effects of arcing in air on the surface state of contact pastilles made of silver-nickel Ag-Ni (60/40). Also, the photoelectric emission from these electrical contacts has been investigated in the spectral range of 196-256 nm. In order to study the effects of arcing on the EWF, the metallic samples were subjected to electrical arcs in air, at atmospheric pressure and room temperature, after that, they have been introduced into the vacuum chamber of an experimental UHV set-up for EWF measurements. Both Fowler method of isothermal curves and linearized Fowler plots were used for the measurement of the EWF by the photoelectric effect. It has been found that the EWF varies with the number of applied arcs. Thus, after 500 arcs in air, the observed EWF increasing is probably due to progressive inclusion of oxide on alloy surface. Microscopic examination is necessary to get better understandings on EWF of silver alloys, for both virgin and arced electrical contacts.

Keywords: Ag-Ni contact materials, arcing effects, electron work function, Fowler methods, photoemission

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Authors: Legkikh Victoria

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The purpose of keeping bi/multilingualism is usually a way to let the child speak two/three languages at the same level. The main problem which normally appears is a mixed language or a domination of one language. The same level of two or more languages would be ideal but practically not easily reachable. So it was made an experiment with a girl with a natural multilingualism as an attempt to avoid a dominant language in the preschool age. The girl lives in Germany and the main languages for her are Italian, Russian and German but she also hears every day English. ‘One parent – one language’ strategy was used since the beginning so Italian and Russian were spoken to her since her birth, English was spoken between the parents and when she was 1,5 it was added German as a language of a nursery. In order to avoid a dominant language, she was always put in international groups with activity in different languages. Even if it was not possible to avoid an interference of languages in this case we can talk not only about natural multilingualism but also about balanced bilingualism in preschool time. The languages have been developing in parallel with different accents in a different period. Now at the age of 6 we can see natural horizontal multilingualism Russian/Italian/German/English. At the moment, her Russian/Italian bilingualism is balanced. German vocabulary is less but the language is active and English is receptive. We can also see a reciprocal interference of all the three languages (English is receptive so the simple phrases are normally said correctly but they are not enough to judge the level of language interference and it is not noticed any ‘English’ mistakes in other languages). After analysis of the state of every language, we can see as a positive and negative result of the experiment. As a positive result we can see that in the age of 6 the girl does not refuse any language, three languages are active, she differentiate languages and even if she says a word from another language she notifies that it is not a correct word, and the most important are the fact, that she does not have a preferred language. As a prove of the last statement it is to be noticed not only her self-identification as ‘half Russian and half Italian’ but also an answer to the question about her ‘mother tongue’: ‘I do not know, probably, when I have my own children I will speak one day Russian and one day Italian and sometimes German’. As a negative result, we can notice that not only a development of all the three languages are a little bit slower than it is supposed for her age but since she does not have a dominating language she also does not have a ‘perfect’ language and the interference is reciprocal. In any case, the experiment shows that it is possible to keep at least two languages without a preference in a pre-school multilingual space.

Keywords: balanced bilingualism, language interference, natural multilingualism, preschool multilingual education

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Authors: Navneetinder Singh, Harprabhjot Singh, Harpreet Singh, Supreet Singh

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Many materials are known to mankind that is widely used for synthesis of corrosion resistant hydrophobic coatings. In the current work, novel hydrophobic composite was synthesized by mixing polytetrafluoroethylene (PTFE) and 20 weight% ceria particles followed by sintering. This composite had same hydrophobic behavior as PTFE. Moreover, composite showed better scratch resistance than virgin PTFE. Pits of plasma sprayed Ni₃Al coating were exploited to hold PTFE composite on the substrate as Superni-75 alloy surface through sintering process. Plasma sprayed surface showed good adhesion with the composite coating during scratch test. Potentiodynamic corrosion test showed 100 fold decreases in corrosion rate of coated sample this may be attributed to inert and hydrophobic nature of PTFE and ceria.

Keywords: polytetrafluoroethylene, PTFE, ceria, coating, corrosion

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Authors: Yassine Ait-El-Aoud, Michael Okomoto, Andrew M. Luce, Alkim Akyurtlu, Richard M. Osgood III

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Light scattering of metal nanoparticles (NPs) has a unique, and technologically important effect on enhancing light absorption in substrates because most of the light scatters into the substrate near the localized plasmon resonance of the NPs. The optical response, such as the resonant frequency and forward- and backward-scattering, can be tuned to trap light over a certain spectral region by adjusting the nanoparticle material size, shape, aggregation state, Metallic vs. insulating state, as well as local environmental conditions. In this work, we examined the light scattering characteristics of ordered arrays of metal nanoparticles and the light trapping, in order to enhance absorption, by measuring the forward- and backward-scattering using a UV/VIS/NIR spectrophotometer. Samples were fabricated using the popular self-assembly process method: dip coating, combined with nanosphere lithography.

Keywords: dip coating, light-scattering, metal nanoparticles, nanosphere lithography

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Authors: Karen B. Ghazaryan

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Recently, the propagation of coupled electromagnetic and elastic waves in magneto-electro-elastic (MEE) structures attracted much attention due to the wide range of application of these materials in smart structures. MEE materials are a class of new artificial composites that consist of simultaneous piezoelectric and piezomagnetic phases. Magneto-electro-elastic composites are built up by combining piezoelectric and piezomagnetic phases to obtain a smart composite that presents not only the electromechanical and magneto-mechanical coupling but also a strong magnetoelectric coupling, which makes such materials highly valuable in technological usage. In the framework of quasi-static approach shear surface and localized waves are considered in magneto-electro-elastic piezo-active structure consisting of functionally graded 6mm hexagonal symmetry group crystals. Assuming that in a functionally graded material the elastic and electromagnetic properties vary in the same proportion in direction perpendicular to the MEE polling direction, special classes of inhomogeneity functions were found, admitting exact solutions for coupled electromagnetic and elastic wave fields. Based on these exact solutions, defining the coupled shear wave field in magneto-electro-elastic composites several modal problems are considered: shear surface waves propagation along surface of a MEE half-space, interfacial wave propagation in a MEE oppositely polarized bi-layer, Love type waves in a functionally graded MEE layer overlying a homogeneous elastic half-space. For the problems under consideration corresponding dispersion equations are deduced analytically in an explicit form and for the BaTiO₃–CoFe₂O₄ crystal numerical results estimating effects of inhomogeneity and piezo effect are carried out.

Keywords: surface shear waves, magneto-electro-elastic composites, piezoactive crystals, functionally graded elastic materials

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Authors: Maria Kralova, Michal Palecek

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We have detected factors leading to recidivism (the Czech Republic data). The employment during imprisonment turned out to be the most significant predictor with a positive effect on reduction of a rate of recidivism. Accordingly, we mainly focus on this predictor and its economic consequences. Smart public policy can cut government costs dramatically as more than a half of prisoners in the Czech Republic are recidivists. The operating cost cut of the Czech prison service could be CZK 127,680,000 (USD 5,889,623) in 2013 if a public policy had been set smarter.

Keywords: cost-cut, effective, optimal, public policy, reducing recidivism

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Authors: Hideyuki Onodera, Ryoji Imai, Masahiro Sakai

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Explosions have occurred in incineration plants in conveyors, ash pits, and other locations. The cause of such explosions is thought to be the reaction of metallic aluminum contained in the ash with water used to cool the ash and prevent scattering, resulting in the generation of hydrogen. Given this background, conveyors and other equipment have been damaged by explosions, which has hindered the stable operation of incineration plants. In addition, workers may be injured by equipment explosions, creating an unsafe situation. To remedy these problems, it is necessary to devise a way to prevent hydrogen explosions from occurring. To overcome this problem, we conducted a hydrogen generation reaction experiment using simulated incinerator ash powder containing aluminum, calcium oxide, and water and confirmed that conditions exist to stop the hydrogen generation reaction. The results of this research may contribute to the suppression of hydrogen explosions at incineration plants.

Keywords: waste incinerated ash, aluminum, water, hydrogen, suppression of hydrogen generation, incineration plant

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Authors: Sari Aouatef, Larabi Amina

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First-principles calculations within density functional theory based are used to investigate the influence of doped rare earth elements on some properties of perovskite systems Dy₀.₀₆₂₅Y₀.₉₃₇₅FeO₃ and Dy₀.₁₂₅ Y₀.₈₇₅ FeO₃. The electronic and magnetic properties are studied by means of the full-potential linearized augmented plane wave method with Vasp code. The calculated densities of states presented in this work identify the semiconducting behavior for Dy₀.₁₂₅ Y₀.₈₇₅ FeO₃, and the semi-metallic behavior for Dy₀.₀₆₂₅Y₀.₉₃₇₅ FeO₃. Besides, to investigate magnetic properties of several compounds, four magnetic configurations are considered (ferromagnetic (FM), antiferromagnetic type A (A-AFM), antiferromagnetic type C (C-AFM) and antiferromagnetic type G (G-AFM). By doping the Dy element, the system shows different changes in the magnetic order and electronic structure. It is found that Dy₀.₀₆₂₅Y₀.₉₃₇₅ FeO₃ exhibits the strongest magnetic change corresponding to the transition to the ferromagnetic order with the largest magnetic moment of 4.997.

Keywords: DFT, Perovskites, multiferroic, magnetic properties

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Authors: Lotfi Hedi Khezami, Mohamed Ben Rabha, N. Sboui, Mounir Gaidi, B. Bessais

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Metal-nano particle-assisted Chemical Etching is an extraordinary developed wet etching method of producing uniform semiconductor nano structure (nano wires) from patterned metallic film on crystalline silicon surface. The metal films facilitate the etching in HF and H2O2 solution and produce silicon nanowires (SiNWs). Creation of different SiNWs morphologies by changing the etching time and its effects on optical and opto electronic properties was investigated. Combination effect of formed SiNWs and stain etching treatment in acid (HF/HNO3/H2O) solution on the surface morphology of Si wafers as well as on the optical and opto electronic properties are presented in this paper.

Keywords: stain etching, porous silicon, silicon nanowires, reflectivity, lifetime, solar cells

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Authors: W. Khati, Y. Guasmi

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The activity of acetylcholinesterase (AChE) was studied in freshwater fish exposed to two heavy metals lead and cadmium. Measurements were made after short exposures (4 and 7 days) at concentrations of 1, 5, and 7μg/L cadmium and 1.25, 2.25, and 5 mg/L of lead. Cadmium induced no significant increases in activity of AChE in the gills for the lowest dose. Except significant inhibition on 7 days. In muscle of Gambusia, under stress of metallic lead, the activity increases compared to the control are noted at 4 days of treatment and inhibitions to 7 days of exposure. The analysis of variance (time, treatment) indicates only a very significant time effect (p<0.05), and as for cadmium, a significant body effect (p<0.01) is recorded. This small fish sedentary, colonizing particularly quiet environments, polluted, can only be the ideal bioindicator of contamination and bioaccumulation of metals. The presence of lead and cadmium in the bodies of fish is a risk factor not only for the lives of these aquatic species, but also for the man who is the top predator at the end of the food chain.

Keywords: biomarkers, bioindicator, environmenlal health, metals

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Authors: Rokas Arlauskas, Donatas Austys, Rimantas Stukas

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Background. The World Health Organization recommends to reduce an intake of added sugar. High consumption of sugar and sweets increases the risk of obesity and overweight. The analysis of the body mass index (BMI) data of the adult population of Lithuania shows that only less than half (45.7%) of the total population has a normal body weight (18.5-24.9 BMI), overweight (25.0-29, 9 BMI) more than a third (36.6 percent), obese (>=30.0 BMI) is 15.4 percent population and underweight (<18.5 BMI) has 2.1 percent population. More men than women are obese (16.5% and 14.9%, respectively). In order to achieve this, alternative sweetening methods by using sweeteners might be employed. However, studies show that attitudes and beliefs might act as a barrier for sugar replacement with sweeteners. In Lithuania, there is a lack of studies on consumption of sugar and sweeteners, including attitudes of Lithuanian residents towards them. Therefore the objective of this study was to assess the attitude of Lithuanian adults towards replacement of added sugar with sweeteners. Methods. A representative sample of Lithuanian population of adults aged 18 to 75 years was formed. A total number of 1008 residents participated. Data was collected using a questionnaire. With respect to social and demografic characteristics, distribution of respondents by answering to one question was analysed. Respondents were asked to indicate their likely behaviour in terms of added sugar if they knew that there a healthier than sugar sweetener exists.Results. Every fifth participant (20.7%) indicated no added sugar consumption and no likely use of the healthier sweetener. Every second respondent among added sugar consumers (40.0% of whole sample) indicated that if they knew about existence of a healthier sweetener than sugar, they would try it and, if liked it, would use it instead of sugar. Approximately 35.0% of whole sample would ignore the fact that healthier than sugar sweetener exists and continue to consume sugar regardless of its effects on health. Younger, urban and higher educated respondents were more likely to opt for a healthier sweetener instead of added sugar (respectively, 45.7% vs. 34.4%, 43.3% vs. 31.2%, 47.6% vs. 37.3% of whole sample, p < 0.05). Conclusions. Half of Lithuanian adult consumers of added sugar would try to replace added sugar with healthier sweetener. Such a reasonable attitude was more prevalent among younger, urban and higher educated respondents.

Keywords: added sugar, lithuanian adult population, sweeteners., food

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Authors: Abanda Wilfred Chick

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Background: According to World Health Organization (WHO), the role of Information and Communication Technologies (ICT) in health sectors of developing nations has been demonstrated to have had a great improvement of fifty percent reduction in mortality and or twenty-five-fifty percent increase in productivity. The objective of this study was to assess the use of information and communication technologies in enhancing health care delivery for Human Immunodeficiency Virus (HIV) patients in Bamenda Health District. Methods: This was a descriptive-analytical cross-sectional study in which 388 participants were consecutively selected amongst health personnel and HIV patients from public and private health institutions involved in Human Immunodeficiency Virus management. Data on socio-demographic variables, the use of information and communication technologies tools, and associated challenges were collected using structured questionnaires. Descriptive statistics with a ninety-five percent confidence interval were used to summarize findings, while Cramer’s V test, logistic regression, and Chi-square test were used to measure the association between variables, Epi info version7.2, MS Excel, and SPSS version 25.0 were utilized for data entry and statistical analysis respectively. Results: Of the participants, one-quarter were health personnel, and three-quarters were HIV patients. For both groups of participants, there was a significant relationship between the use of ICT and demographic information such as level of education, marital status, and age (p<0.05). For the impediments to using ICT tools, a greater proportion identified the high cost of airtime or internet bundles, followed by an average proportion that indicated inadequate training on ICT tools; for health personnel, the majority said inadequate training on ICT tools/applications and half said unavailability of electricity. Conclusion: Not up to half of the HIV patients effectively make use of ICT tools/applications to receive health care. Of health personnel, three quarters use ICTs, and only one quarter effectively use mobile phones and one-third of computers, respectively, to render care to HIV patients.

Keywords: ICT tools, HIV patients, health personnel, health care delivery

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Authors: Talha Ali Khan

Abstract:

Discovering different energy resources to full fill the world growing demand is now one of the society’s bigger challenge for the next half-century. The main task is to convert the sun radiation into electricity via photovoltaic solar cells which is suddenly decreasing $/watt of delivered solar electricity. Therefore, in this context, the sun trackers are those devices that can be used to ameliorate efficiency. In this paper, a variety of the sun tracking systems are evaluated and their merits and demerits are highlighted. The most adept and proficient sun-tracking devices are polar axis and azimuth-elevation types.

Keywords: dual axis, fixed axis, sun tracker, MPPT

Procedia PDF Downloads 578

Authors: Oqba Basal, Andras Szabo

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Using mineral fertilization is increasing worldwide, as it is claimed to be majorly responsible for achieving high yields; however, the negative impacts of mineral fertilization on soil and environment are becoming more obvious, with alternative methods being more necessary and applicable, especially with the current climatic changes which have imposed serious abiotic stresses, such as drought. An experiment was made during 2017 growing season in Debrecen, Hungary to investigate the effects of inoculation and N fertilization on the seed yield and protein concentration of the soybean (Glycine max (L.) Merr.) cultivar (Panonia Kincse) under three different irrigation regimes: severe drought stress (SD), moderate drought stress (MD) and control with no drought stress (ND). Three N fertilizer rates were applied: no N fertilizer (0 N), 35 kg ha⁻¹ of N fertilizer (35 N) and 105 kg ha⁻¹ of N fertilizer (105 N). Half of the seeds in each treatment was inoculated with Bradyrhizobium japonicum inoculant, and the other half was not inoculated. The results showed significant differences in the seed yield associated with inoculation, irrigation and the interaction between them, whereas there were no significant differences in the seed yield associated with fertilization alone or in interaction with inoculation or irrigation or both. When seeds were inoculated, yield was increased when (35 N) was applied compared to (0 N) but not significantly; however, the high rate of N fertilizer (105 N) reduced the yield to a level even less than (0 N). When seeds were not inoculated, the highest rate of N increased the yield the most compared to the other two N fertilizer rates whenever the drought was present (moderate or severe). Under severe drought stress, inoculation was positively and significantly correlated with yield; however, adding N fertilizer increased the yield of uninoculated plants compared to the inoculated ones, regardless of the rate of N fertilizer. Protein concentration in the seeds was significantly affected by irrigation and by fertilization, but not by inoculation. Protein concentration increased as the N fertilization rate increased, regardless of the inoculation or irrigation treatments; moreover, increasing the N rate reduced the correlation coefficient of protein concentration with the irrigation. It was concluded that adding N fertilizer is not always recommended, especially when seeds are inoculated before being sown; however, it is very important under severe drought stress to sustain yield. Enhanced protein concentrations could be achieved by applying N fertilization, whether the seeds were pre-inoculated or not.

Keywords: drought stress, N fertilization, protein concentration, soybean

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Authors: Khamael Abualnaja, Hala M. Abo-Dief

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Silver nanoparticles (AgNPs) are the subject of important recent interest, present in a large range of applications such as electronics, catalysis, chemistry, energy, and medicine. Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are quite often toxic and flammable. In this work, we describe an effective and environmental-friendly technique of green synthesis of silver nanoparticles. Silver nanoparticles (AgNPs) synthesized using silver nitrate solution and the extract of mint, basil, orange peel and Tangerines peel which used as reducing agents. Silver Nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and UV–Vis absorption spectroscopy. SEM analysis showed the average particle size of mint, basil, orange peel, Tangerines peel are 30, 20, 12, 10 nm respectively. This is for the first time that any plant extract was used for the synthesis of nanoparticles.

Keywords: silver nanoparticles, green synthesis, scanning electron microscopy, plants

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Authors: I. A. Harris, J. M. Naylor

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Antibiotic guidelines are published in order to reduce the risk of perioperative infection in orthopaedics. We surveyed 20 orthopaedic hospitals in Australia to determine their protocols for antibiotic prophylaxis around joint replacement surgery. We tested the protocols against Australian guidelines. We found that less than half of all protocols adhered to Australian guidelines. This indicates that current practice may lead to increased infection rates and increased antibiotic resistance.

Keywords: antibiotics, practice guidelines, orthopaedic surgery, joint replacement

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Authors: Kiknadze T, Tevdorashvili G, Muzashvili T, Gachechiladze M, Burkadze G

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Uterine leiomyomas decrease the quality of life by causing significant morbidity among women of reproductive age. Histologically various types of leiomyoma's can be differentiated. We have analysed th histopathological, proliferation, apoptotic, and hormonal profile in different types of leiomyomas. Study included altogether140 cases distributed into the following groups: group I-normal myometrium (20cases), group II-classic leiomyoma (69 cases), group III-cellular leiomyoma (15 cases), group IV-bizarre cell/atypical leiomyoma (22cases), group V-smooth muscle tumors of uncertain malignancy potential (STUMP) (8 cases) and group VI-leiomyosarcoma (6 cases). Together with classic histopathological features such as nuclear atypia, cellularity, presence of mitoses, vasculature and necrosis, immunohistochemical phenotype using antibodies against Ki67,Cas3, ER, and PR were analysed. The results of our study showed that leiomyomas are charterised with variable histopathological and immunohistocthemical phenotype. Histopathological parameters mainly correlate with the degree of malignancy except for two bizarre/atypical leiomyoma and STUMP, where two distinct subgroups could be identified. In bizarre/ atipycal leiomyoma, 31% of cases are characterized with the features of classic leiomyoma, whilst the rest of the cases reveal more atipycal phenotype. In STUMP 37.5 % of cases are characterized with the features of atipycal leiomyomas. The result of the immunohistochemical study also reveald that half of bizarre/atipycal leiomyomas are characterized with the low proliferation index, high apoptotic index, and high ER and PR index, whilst another half is characterized with high proliferation index, low apoptotic index, and low ER and PR index. Similarly, part of the STUMP cases are characterized with low proliferation index, high Er, and PR index and whilst part of the cases are characterized whith high proliferation index, low apoptotic index and low ER and PR index. The results of the histopathological and immunohistochemical study indicate that these two entities represent the heterogenous group of diseases, which might be the explanation of their different prognosis. Presented histopathological and immunohistochemical features should be considered in the diagnosis of myometrial smooth muscle tumors.

Keywords: proliferation, apoptosis, bizarre cell, leiomyosarcoma., leiomyoma

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Authors: Rainer Goetz, Zahra Ahaliabadeh, Princess S. Llanos, Aliaksandr S. Bandarenka, Tanja Kallio

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In order to understand the electrochemistry of all-solid-state batteries (ASSBs), the use of electrochemical equivalent circuits with a physical meaning is essential. A model battery is needed whose characterization is independent of the influence of the complex battery assembly. Lithium-Ion Conducting Glass-Ceramic (LICGC), a model solid electrolyte, is chosen for its stability in the air, but on the other hand, it is also well-known for its instability against metallic lithium upon direct contact. Hence, as a first step towards a model ASSB, the interface between lithium and the solid electrolyte (SE) is stabilized with thin (5 nm and 10 nm) coatings of titanium oxide (TO) and lithium titanium oxide (LTO). Impedance data shows that both materials are able to protect the SE surface from rapid degradation due to reducing lithium and, therefore, can serve as a protective interlayer on the anode side of a model ASSB.

Keywords: all-solid-state battery, lithium anode, solid electrolytes, interlayers

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Authors: Wei Jin

Abstract:

Efficient and selective metal recovery from emerging solid waste, such as spent lithium batteries, electronic waste and SCR catalysts, is of great importance from both environmental and resource considerations. In order to overcome the bottlenecks of long flow-sheet and severe secondary pollution in conventional processes, the rational design of 2-electron oxygen reduction reaction (ORR) and capacitive deionization (CDI) nanomaterials were developed for the precise electrochemical metal recovery. It has been demonstrated that the modified carbon nanomaterials can be employed as 2e ORR to produce H2O2 in aqueous solution, in which the metal can be leached out from the solid waste as ions. Moreover, the multi-component metallic solution can be electrochemically extracted with good efficiency and selectivity with the nanoporous aerogel. Each system presents stable performance for long-term operation and can be used in industrial solid waste treatment. This study provides a materials-oriented, cleaner metal recovery approach for strategic metal resources sustainability.

Keywords: electrochemistry, metal recovery, waste steams, nanomaterials

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Authors: Yu-Jen Shih, Yao-Hui Hunag

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Electrocoagulation (EC) using metallic nickel foam as anode and cathode for the removal of boron from solution was studied. The electrolytic parameters included pH, current density, and initial boron concentration for optimizing the EC process. Experimental results showed that removal efficiency was increased by elevating pH from 4.0 to 8.0, and then decreased at higher pH. The electrolytic efficacy was not affected by current density. In respect of energy consumption, 1.25 mA/cm2 of current density was acceptable for an effective EC of boron, while increasing boric acid from 10 to 100 ppm-B did not impair removal efficiency too much. Cyclic voltammetry indicated that the oxide film, Ni(OH)2 and NiOOH, at specific overpotentials would result in less weight loss of anode than that predicted by the Faraday’s law. The optimal conditions under which 99.2% of boron was removed and less than 1 ppm-B remained in the electrolyte would be pH 8, four pairs of electrodes, and 1.25 mA/cm2 in 120 min as treating wastewaters containing 10 ppm-B. XRD and SEM characterization suggested that the granular crystallites of hydroxide precipitates was composed of theophrastite.

Keywords: borohydrides, hydrogen generation, NiOOH, electrocoagulation, cyclic voltammetry, boron removal

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Authors: Bilal Jabakhanji, Dimitris Kazazis, Adrien Michon, Christophe Consejo, Wilfried Desrat, Benoit Jouault

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In this paper, we investigate the electrical properties of graphene grown by Chemical Vapor Deposition (CVD) on the Si face of SiC substrates. Depending on the growth condition, hole or electron doping can be achieved, down to a few 1011cm−2. The high homogeneity of the graphene and the low intrinsic carrier concentration, allow the remarkable observation of the Half Integer Quantum Hall Effect, typical of graphene, at the centimeter scale.

Keywords: graphene, quantum hall effect, chemical vapor, deposition, silicon carbide

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Authors: Talha Ali Khan

Abstract:

Discovering different energy resources to fulfill the world's growing demand is now one of the society’s bigger challenges for the next half-century. The main task is to convert the sun radiation into electricity via photovoltaic solar cells which is suddenly decreasing $/watt of delivered solar electricity. Therefore, in this context the sun trackers are those devices that can be used to ameliorate efficiency. In this paper, a variety of the sun tracking systems are evaluated and their merits and demerits are highlighted. The most adept and proficient sun-tracking devices are polar axis and azimuth-elevation types.

Keywords: dual axis, fixed axis, sun tracker, sun radiation

Procedia PDF Downloads 454

Authors: Asma Abdullah, Awais Khan, Reem Al-Ghumlasi, Pritam Kumari, Yasir Nawaz

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Introduction: This study verified the potential applications of two Oblique Wing configurations that were initiated by the Germans Aerodynamicists during the WWII. Due to the end of the war, this project was not completed and in this research is targeting the revival of German Oblique biplane configuration. The research draws upon the use of two Oblique wings mounted on the top and bottom of the fuselage through a single pivot. The wings are capable of sweeping at different angles ranging from 0° at takeoff to 60° at cruising Altitude. The top wing, right half, behaves like a forward swept wing and the left half, behaves like a backward swept wing. Vice Versa applies to the lower wing. This opposite deflection of the top and lower wing cancel out the rotary moment created by each wing and the aircraft remains stable. Problem to better understand or solve: The purpose of this research is to investigate the potential of achieving improved aerodynamic performance and efficiency of flight at a wide range of sweep angles. This will help examine the most accurate value for the sweep angle at which the aircraft will possess both stability and better aerodynamics. Explaining the methods used: The Aircraft configuration is designed using Solidworks after which a series of Aerodynamic prediction are conducted, both in the subsonic and the supersonic flow regime. Computations are carried on Ansys Fluent. The results are then compared to theoretical and flight data of different Supersonic fighter aircraft of the same category (AD-1) and with the Wind tunnel testing model at subsonic speed. Results: At zero sweep angle, the aircraft has an excellent lift coefficient value with almost double that found for fighter jets. In acquiring of supersonic speed the sweep angle is increased to maximum 60 degrees depending on the mission profile. General findings: Oblique biplane can be the future fighter jet aircraft because of its high value performance in terms of aerodynamics, cost, structural design and weight.

Keywords: biplane, oblique wing, sweep angle, supercritical airfoil

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Authors: Sapan Mohan Saini

Abstract:

In this work, we report the calculations on the electronic and optical properties of YNi₄Si-type GdNi₅ compound. Calculations are performed using the full-potential augmented plane wave (FPLAPW) method in the framework of density functional theory (DFT). The Coulomb corrected local-spin density approximation (LSDA+U) in the self-interaction correction (SIC) has been used for exchange-correlation potential. Spin polarised calculations of band structure show that several bands cross the Fermi level (EF) reflect the metallic character. Analysis of density of states (DOS) demonstrates that spin up Gd-f states lie around 7.5 eV below EF and spin down Gd-f lie around 4.5 eV above EF. We found Ni-3d states mainly contribute to DOS from -5.0 eV to the EF. Our calculated results of optical conductivity agree well with the experimental data.

Keywords: electronic structure, optical properties, FPLAPW method, YNi₄Si-type GdNi₅

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Authors: Brenda Cecilia Ledesma, Andrea Beltramone

Abstract:

This work deals with the bio-waste valorization approach for catalyst development, the use of products derived from biomass as raw material and the obtaining of biofuels. In this research, activated carbons were synthesized from the orange peel using different synthesis conditions. With the activated carbons obtained with the best structure and texture, PtIr bimetallic catalysts were prepared. Carbon activation was carried out through a chemical process with phosphoric acid as an activating agent, varying the acid concentration, the ratio substrate/activating agent and time of contact between them. The best support was obtained using a carbonization time of 1 h, the temperature of carbonization of 470oC, the phosphoric acid concentration of 50 wt.% and a BET area of 1429 m2/g. Subsequently, the metallic nanoparticles were deposited in the activated carbon to use the solid as a catalytic material for the hydrogenation of HMF to 2,5-DMF. The catalyst presented an excellent performance for biofuels generation.

Keywords: orange peel, bio-waste valorization, platinum, iridium, 5-hydroxymethylfurfural

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Authors: B. Medjahed, M. A. Didi, B. Guezzen

Abstract:

This work concerns with the experimental study of the adsorption of the Ni(II) on bentonite. The effects of various parameters such as contact time, stirring rate, initial concentration of Ni(II), masse of clay, initial pH of aqueous solution and temperature on the adsorption yield, were carried out. The study of the effect of the ionic strength on the yield of adsorption was examined by the identification and the quantification of the present chemical species in the aqueous phase containing the metallic ion Ni(II). The adsorbed species were investigated by a calculation program using CHEAQS V. L20.1 in order to determine the relation between the percentages of the adsorbed species and the adsorption yield. The optimization process was carried out using 2³ factorial designs. The individual and combined effects of three process parameters, i.e. initial Ni(II) concentration in aqueous solution (2.10⁻³ and 5.10⁻³ mol/L), initial pH of the solution (2 and 6.5), and mass of bentonite (0.03 and 0.3 g) on Ni(II) adsorption, were studied.

Keywords: adsorption, bentonite, factorial design, Nickel(II)

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Authors: Ahmet Yonetken, Ayhan Erol

Abstract:

The microstructure, mechanical properties and corrosion characteristics of Ni plated %10Al2O3-%40Co-%20Cr and %10Ti powders were investigated using specimens produced by tube furnace sintering at 800-1200°C temperature. A uniform nickel layer on Al2O3-Co-Cr and Ti powders was deposited prior to sintering using electroless plating technique. A composite consisting of quintet additions, a metallic phase, Ti,Cr and Co including a ceramic phase, alumina, within a matrix of Ni has been prepared under Ar shroud and then tube furnace sintered. XRD, SEM (Scanning Electron Microscope), corrosion behavior in acidic media were investigated to characterize the properties of the specimens. Experimental results carried out for composition (%10Al2O3-%40Co-%20Cr- %10Ti)20Ni at 1200°C suggest that the best properties as 312.18HV were obtained at 1200°C.

Keywords: sintering, intermetallic, Electroless nickel plating, composite

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Authors: Marie Kudrnova, Jana Petru

Abstract:

This study is part of the international research - Materials for Molten Salt Reactors (MSR) and addresses the part of the project dealing with the corrosion behavior of candidate construction materials. Inconel 625 was characterized by x-ray photoelectron spectroscopy (XPS) before and after high–temperature experiment in molten salt. The experiment was performed in a horizontal tube furnace molten salt reactor, at 450 °C in argon, at atmospheric pressure, for 150 hours. Industrially produced HITEC salt was used (NaNO3, KNO3, NaNO2). The XPS study was carried out using the ESCAProbe P apparatus (Omicron Nanotechnology Ltd.) equipped with a monochromatic Al Kα (1486.6 eV) X-ray source. The surface layer on alloy 625 after exposure contains only Na, C, O, and Ni (as NiOx) and Nb (as NbOx BE 206.8 eV). Ni was detected in the metallic state (Ni0 – Ni 2p BE-852.7 eV, NiOx - Ni 2p BE-854.7 eV) after a short Ar sputtering because the oxide layer on the surface was very thin. Nickel oxides can form a protective layer in the molten salt, but only future long-term exposures can determine the suitability of Inconel 625 for MSR.

Keywords: Inconel 625, molten salt, oxide layer, XPS

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Authors: Eimar Yadir Quintero Tapias

Abstract:

Background: Science is not generally self-correcting; many clinical studies end with the same conclusion "more research is needed." This study hypothesizes that first, we need a better appraisal of the available (and unavailable) evidence instead of creating more of the same false inquiries. Methods: Systematic review of ClinicalTrials.gov study records using the following Boolean operators: (food OR nut OR milk OR egg OR shellfish OR wheat OR peanuts) AND (allergy OR allergies OR hypersensitivity OR hypersensitivities). Variables included the status of the study (e g., active and completed), availability of results, sponsor type, sample size, among others. To determine the rates of non-publication in journals indexed by PubMed, an advanced search query using the specific Number of Clinical Trials (e.g., NCT000001 OR NCT000002 OR...) was performed. As a prophylactic measure to prevent P-hacking, data analyses only included descriptive statistics and not inferential approaches. Results: A total of 2092 study records matched the search query described above (date: September 13, 2019). Most studies were interventional (n = 1770; 84.6%) and the remainder observational (n = 322; 15.4%). Universities, hospitals, and research centers sponsored over half of these investigations (n = 1208; 57.7%), 308 studies (14.7%) were industry-funded, and 147 received NIH grants; the remaining studies got mixed sponsorship. Regarding completed studies (n = 1156; 55.2%), 248 (21.5%) have results available at the registry site, and 417 (36.1%) matched NCT numbers of journal papers indexed by PubMed. Conclusions: The internal and external validity of human research is critical for the appraisal of medical evidence. It is imperative to analyze the entire dataset of clinical studies, preferably at a patient-level anonymized raw data, before rushing to conclusions with insufficient and inadequate information. Publication bias and non-registration of clinical trials limit the evaluation of the evidence concerning therapeutic interventions for food allergy, such as oral and sublingual immunotherapy, as well as any other medical condition. Over half of the food allergy human research remains unpublished.

Keywords: allergy, clinical trials, immunology, systematic reviews

Procedia PDF Downloads 137