Search results for: dosimetric materials

Authors: Le-Quyen Nguyen, Hoang Van Bui, Ngoc Thi Tran, Binh Thanh Le, Linus Olson, Thanh Quang Le

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Objective: We compared of outcomes between infected and non-infected COVID-19 pregnant at the largest obstetrics and gynecology hospital in southern Vietnam. Materials and Methods: A retrospective study was conducted at gestational age (GA) 28-42 weeks, who terminated pregnancy and had a real-time PCR test for SARS-CoV-2 at Tu Du Hospital. Demographic, clinical, laboratory, and epidemiological data were collected from hospital electronic-medical-records. Diagnosis and screening of SARS-CoV-2 used Real-time-PCR. Results: From July to October 2021, 9,246 pregnant with GA of 28-42 weeks were delivered, including 664 infected with COVID-19 and 8,582 non-infected. The cesarean section (CS) rates of pregnant with and without COVID-19 were 47.3% and 46.0%. At GA 32-34 weeks, the rate of CS with COVID-19 was 5.07 times higher than without. The rate of postpartum hemorrhage (PPH) and the Apgar score between these two groups were similar. The mortality rate of infected pregnants was 2.26%. Conclusions: COVID-19 infection increased the CS rate in the group of preterm pregnancies from 32 to less than 34 weeks. COVID-19 did not increase the risk of complications related to adverse pregnancy outcomes such as PPH, Apgar scores, the ratio of stillbirths, deaths due to malformation, and fetal deaths in labor.

Keywords: COVID-19, SARS-CoV-2, pregnancy, outcome, vietnam

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Authors: Mazen Al-Bulaihed, Nissar Wani, Abdulrahman Al-Arainy, Yasin Khan

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Partial Discharge (PD) measurements are widely used for diagnostic purposes in electrical equipment used in power systems. The main cause of these measurements is to prevent large power failures as cables are prone to aging, which usually results in embrittlement, cracking and eventual failure of the insulating and sheathing materials, exposing the conductor and risking a potential short circuit, a likely cause of the electrical fire. Many distribution networks rely heavily on medium voltage (MV) power cables. The presence of joints in these networks is a vital part of serving the consumer demand for electricity continuously. Such measurements become even more important when the extent of dependence increases. Moreover, it is known that the partial discharge in joints and termination are difficult to track and are the most crucial point of failures in large power systems. This paper discusses the diagnostic techniques of four samples of XLPE insulated cable joints, each included with a different type of defect. Experiments were carried out by measuring PD and tanδ at very low frequency applied high voltage. The results show the importance of combining PD and tanδ for effective cable assessment.

Keywords: partial discharge, tan delta, very low frequency, XLPE cable

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Authors: Youcef Faci, Djillali Allou, Ahmed Mebtouche, Badredine Maalem

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The inclination of the bolt in a fastened joint of composite material during a tensile test can be influenced by several parameters, including material properties, bolt diameter and length, the type of composite material being used, the size and dimensions of the bolt, bolt preload, surface preparation, the design and configuration of the joint, and finally testing conditions. These parameters should be carefully considered and controlled to ensure accurate and reliable results during tensile testing of composite materials with fastened joints. Our work focuses on the effect of the stacking sequence and the geometry of specimens. An experimental test is carried out to obtain the inclination of a bolt during a tensile test of a composite material using acoustic emission and digital image correlation. Several types of damage were obtained during load. Digital image correlation techniques permit to obtain the inclination of bolt angle value during tensile test. We concluded that the inclination of the bolt during a tensile test of a composite material can be related to the damage that occurs in the material. It can cause stress concentrations and localized deformation in the material, leading to damage such as delamination, fiber breakage, matrix cracking, and other forms of failure.

Keywords: damage, digital image correlation, bolt inclination angle, joint

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Authors: H. Elmsellem, A. Aouniti, S. Radi, A. Chetouani, B. Hammouti

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The synthesis of new organic molecules offers various molecular structures containing heteroatoms and substituents for corrosion protection in acid pickling of metals. The most synthesized compounds are the nitrogen heterocyclic compounds, which are known to be excellent complex or chelate forming substances with metals. The choice of the inhibitor is based on two considerations: first it could be synthesized conveniently from relatively cheap raw materials, secondly, it contains the electron cloud on the aromatic ring or, the electro negative atoms such as nitrogen and oxygen in the relatively long chain compounds. In the present study, (NE)‐2‐methyl‐N‐(thiophen‐2‐ylmethylidene) aniline(T) was synthesized and its inhibiting action on the corrosion of mild steel in 1 M hydrochloric acid was examined by different corrosion methods, such as weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The experimental results suggest that this compound is an efficient corrosion inhibitor and the inhibition efficiency increases with the increase in inhibitor concentration. Adsorption of this compound on mild steel surface obeys Langmuir’s isotherm. Correlation between quantum chemical calculations and inhibition efficiency of the investigated compound is discussed using the Density Functional Theory method (DFT).

Keywords: mild steel, Schiff base, inhibition, corrosion, HCl, quantum chemical

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Authors: Tarik Elaujali

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This study examines a new media effective theory was developed by the author, it is called ‘The Effervescent Disk Theory’ (EDT). The theory main goal is to affect the unaffected audience who are either not exposing to a particular message or do not show interest in it. EDT suggest melting down messages that means to be affected within the media materials which are selected willingly by the audience themselves. A certain set of procedures to test EDT hypotheses were taken and illustrated in this study. A sample of 342 respondents (males & females) was collected from Tripoli University in Libya during the academic year 2013-2014. The designated sample is representing students who were failing to pass the English module for beginners’. This study aims to change the students’ negative notion about the importance of learning English, and to put their new idea into action. The theory seeks to affect audience cognition, emotions, and behaviors. EDT was applied in the present study alongside the media dependency theory. EDT hypotheses were confirmed, study results denoted that 73.6 percentage of the students responded positively and passed their English exam for beginners after being exposed selectively to their favorite TV program that contains a dissolved messages about the importance and vitality of learning English language.

Keywords: effervescent disk theory, selective exposure, media dependency, Libyan students

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Authors: V. Balamuralidhara

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The aim of the present work was to develop Paclitaxel loaded polyacrylamide grafted guar gum nanoparticles as pH responsive nanoparticle systems for targeting colon. The pH sensitive nanoparticles were prepared by modified ionotropic gelation technique. The prepared nanoparticles showed mean diameters in the range of 264±0.676 nm to 726±0.671nm, and a negative net charge 10.8 mV to 35.4mV. Fourier Transformed Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC) studies suggested that there was no chemical interaction between drug and polymers. The encapsulation efficiency of the drug was found to be 40.92% to 48.14%. The suitability of the polyacrylamide grafted guar gum ERN’s for the release of Paclitaxel was studied by in vitro release at pH 1.2 and 7.4. It was observed that, there was no significant amount of drug release at gastric pH and 97.63% of drug release at pH 7.4 was obtained for optimized formulation F3 at the end of 12 hrs. In vivo drug targeting performance for the prepared optimized formulation (F3) and pure drug Paclitaxel was evaluated by HPLC. It was observed that the polyacrylamide grafted guar gum can be used to prepare nanoparticles for targeting the drug to the colon. The release performance was greatly affected by the materials used in ERN’s preparation, which allows maximum release at colon’s pH. It may be concluded that polyacrylamide grafted guar gum nanoparticles loaded with paclitaxel have desirable release responsive to specific pH. Hence it is a unique approach for colonic delivery of drug having appropriate site specificity and feasibility and controlled release of drug.

Keywords: colon targeting, polyacrylamide grafted guar gum nanoparticles, paclitaxel, nanoparticles

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Authors: Ravindra N. Singh, Dheerendra P. Singh

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Recent discoveries of Bronze Age artefacts, tin slag, furnaces and crucibles, together with new geological evidence on tin deposits in Tosham area of Bhiwani district in Haryana (India) provide the opportunity to survey the evidence for possible sources of tin and the use of bronze in the Harappan sites of north western India. Earlier, Afghanistan emerged as the most promising eastern source of tin utilized by Indus Civilization copper-smiths. Our excavations conducted at Khanak near Tosham mining area during 2014 and 2016 revealed ample evidence of metallurgical activities as attested by the occurrence of slag, ores and evidences of ashes and fragments of furnaces in addition to the bronze objects. We have conducted petrological, XRD, EDAX, TEM, SEM and metallography on the slag, ores, crucible fragments and bronze objects samples recovered from Khanak excavations. This has given positive indication of mining and metallurgy of poly-mettalic Tin at the site; however, it can only be ascertained after the detailed scientific examination of the materials which is underway. In view of the importance of site, we intend to excavate the site horizontally in future so as to obtain more samples for scientific studies.

Keywords: archaeometallurgy, problem of tin, metallography, indus civilization

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Authors: Jaden Lu, Olivia Lu

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Despite the remarkable advancement of solar cell technology, the challenge of optimizing total solar energy harvest efficiency persists, primarily due to significant heat loss. This excess heat not only diminishes solar panel output efficiency but also curtails its operational lifespan. A promising approach to address this issue is the conversion of surplus heat into electricity. In recent years, there is growing interest in the use of thermoelectric generators (TEG) as a potential solution. The integration of efficient TEG devices holds the promise of augmenting overall energy harvest efficiency while prolonging the longevity of solar panels. While certain research groups have proposed the integration of solar cells and TEG devices, a substantial gap between conceptualization and practical implementation remains, largely attributed to low thermal energy conversion efficiency of TEG devices. To bridge this gap and meet the requisites of practical application, a feasible strategy involves the incorporation of a substantial number of p-n junctions within a confined unit volume. However, the manufacturing of high-density TEG p-n junctions presents a formidable challenge. The prevalent solution often leads to large device sizes to accommodate enough p-n junctions, consequently complicating integration with solar cells. Recently, the adoption of 3D printing technology has emerged as a promising solution to address this challenge by fabricating high-density p-n arrays. Despite this, further developmental efforts are necessary. Presently, the primary focus is on the 3D printing of vertically layered TEG devices, wherein p-n junction density remains constrained by spatial limitations and the constraints of 3D printing techniques. This study proposes a novel device configuration featuring horizontally arrayed p-n junctions of Bi2Te3. The structural design of the device is subjected to simulation through the Finite Element Method (FEM) within COMSOL Multiphysics software. Various device configurations are simulated to identify optimal device structure. Based on the simulation results, a new TEG device is fabricated utilizing 3D Selective laser melting (SLM) printing technology. Fusion 360 facilitates the translation of the COMSOL device structure into a 3D print file. The horizontal design offers a unique advantage, enabling the fabrication of densely packed, three-dimensional p-n junction arrays. The fabrication process entails printing a singular row of horizontal p-n junctions using the 3D SLM printing technique in a single layer. Subsequently, successive rows of p-n junction arrays are printed within the same layer, interconnected by thermally conductive copper. This sequence is replicated across multiple layers, separated by thermal insulating glass. This integration created in a highly compact three-dimensional TEG device with high density p-n junctions. The fabricated TEG device is then attached to the bottom of the solar cell using thermal glue. The whole device is characterized, with output data closely matching with COMSOL simulation results. Future research endeavors will encompass the refinement of thermoelectric materials. This includes the advancement of high-resolution 3D printing techniques tailored to diverse thermoelectric materials, along with the optimization of material microstructures such as porosity and doping. The objective is to achieve an optimal and highly integrated PV-TEG device that can substantially increase the solar energy harvest efficiency.

Keywords: thermoelectric, finite element method, 3d print, energy conversion

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Authors: Angelis P. Barlampas

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Target: The (SARS-CoV-2) is still a threat. AI software could be useful, categorizing the disease into different severities and indicate the extent of the lesions. Materials and methods: AI is a new revolutionary technique, which uses powered computerized systems, to do what a human being does more rapidly, more easily, as accurate and diagnostically safe as the original medical report and, in certain circumstances, even better, saving time and helping the health system to overcome problems, such as work overload and human fatigue. Results: It will be given an effort to describe to the inexperienced reader (see figures), as simple as possible, how an artificial intelligence system diagnoses computed tomography pictures. First, the computerized machine learns the physiologic motives of lung parenchyma by being feeded with normal structured images of the lung tissue. Having being used to recognizing normal structures, it can then easily indentify the pathologic ones, as their images do not fit to known normal picture motives. It is the same way as when someone spends his free time in reading magazines with quizzes, such as <> and <>. General conclusion: The AI mimics the physiological processes of the human mind, but it does that more efficiently and rapidly and provides results in a few seconds, whereas an experienced radiologist needs many days to do that, or even worse, he is unable to accomplish such a huge task.

Keywords: covid-19, artificial intelligence, automated imaging, CT, chest imaging

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Authors: Md. Nakib Ul Hasan, Md. Ariful Islam, Md. Sumon Miah, Misbah Ul Hoque, Bulbul Ahmed

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The variability of cotton fiber characteristics has always been influenced by origin, weather conditions, method of culturing, and harvesting. Spinners work tirelessly to ensure consistent yarn quality by using the different origins of fibers to maximizes the profit margin. Spinners often fail to select desired raw materials of various origins to achieve an appropriate mixing plan due to the lack of knowledge on the interrelationship among fiber properties. The purpose of this research is to investigate the correlations among dominating fiber properties such as micronaire, strength, breaking elongation, upper half mean length, length uniformity index, short fiber index, maturity, reflectance, and yellowness. For this purpose, fiber samples from 500 Indian cotton bales and 350 Greek cotton bales were collected and tested using the high volume instrument (HVI). The fiber properties dataset was then compiled and analyzed using python 3.7 to determine the correlations matrix. Results show that Indian cotton fiber have highest correlation between strength-mat = 0.84, followed by SFI-Unf =-0.83, and Neps-Unf = -0.72. Greek cotton fiber, in contrast, have highest correlation between SFI-Unf =-0.98, followed by SFI-Mat = 0.89, +b-Len = 0.84, and Str-Mat = 0.74. Overall, the Greek cotton fiber showed a higher correlational matrix than compared to that of Indian cotton fiber.

Keywords: cotton fiber, fiber properties correlation, Greek cotton, HVI, Indian cotton, spinning

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Authors: Marco Khalaf Ayad Milhaail

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In thinking about the role of legal rules and their impact on social ethics and social structures, scholars have explored many issues related to gender, power, and ideology. First, it provides a framework for defining feminist legal studies through an overview of the field's evolution in terms of equality, rights, and justice. Secondly, it encourages those interested in equality, rights, and justice regarding women's issues to participate in international comparative law research. Third, we must emphasize that those seeking solutions to disability and discrimination must be aware of the need to confront the so-called undermining of culture. Therefore, an effective way for women to solve this problem is to rely heavily on international law, which establishes basic legal principles such as gender equality, rights, and justice and can help create a domestic environment. Woman has gained many advantages by adopting the law of Divorce in the Islamic Sharea. Any Egyptian woman can get divorce by letting her rightful rights and wealth to her husband in return for her freedom.

Keywords: stability, harsh environments, techniques, thermal, properties, materials, applications, brittleness, fragility, disadvantages, bank, branches, profitability, setting prediction, effective target, measurement, evaluation, performance, commercial, business, profitability, sustainability, financial, system, banks

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Authors: M. M. Alsharif

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4-Nonylphenol Compound is widely used as an element of detergents, paints, insecticides and many others products. It is known that the existence of this compound may lead to the emission of estrogenic responses in mammals, birds and fish. It is described as pollutant since it causes disorder of endocrine glands. In previous studies, it was proven that this compound exists in water and in the materials precipitated in Red Sea coast in Jeddah near the drains of processed drainage water and near the drainage site of the residuals of paper factories. Therefore, this study aimed to evaluate the cytogenetic aberrations caused by 4-nonylphenol through exposing Talapia Fishes to aquatic solution of the compound with 0, 15, 30 microgram/liter for one month. Samples of gills and liver were collected for micronuclei, nuclear abnormalities and measuring DNA and RNA amount in the treated fish. The results pointed out that there is a significant increase in the numbers of micronuclei in the fish exposed to the former concentrations as compared to the control group. Exposing fishes to 4-nonylphenol resulted in an increased amount of both DNA and RNA, compared to the control group. There is a positive correlation between the amount of the compound (i.e. dosage dependent effect) and the inspiring for cytogenetic effect on Talapia fishes in Jeddah. Therefore, micronucleus test, DNA and RNA contents can be considered as an index of cumulative exposure, which appear to be a sensitive model to evaluate genotoxic effects of 4-Nonylphenol compound on fish.

Keywords: genotoxic, 4-nonylphenol, micronuclei, fish, DNA, RNA

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Authors: Dana Aljadaa, Hasim Altan

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Japan’s strategy is based on improving the current resources and productivity by identifying the environmental challenges to progress further in many areas. For example, it will help in understanding the competitive challenges in the industry, emerging innovation, and other progresses. The present study seeks to examine the characteristics of sustainable practices using materials that will last longer and following environmental policies. There has been a major emphasis since 1990s and onwards about recycling and preserving the environment. Furthermore, the present paper analyses and argues how national interest in policy increases resource productivity. It is a universal law, but these actions may be different based on the unique situation of the country. In addition, the present study explains some of the strategies developed by the Environmental Agency of Japan in the last few years. There are a few resources reviewed involving ‘Strategy for an Environmental Nation in the 21st Century’ from 2001, ‘Clean Asia Initiative’ from 2008, and ‘New Growth Strategy’ from 2010. The present paper also highlights the emphasis on increasing efficiency, as it is an important part of sustainability. We finally conclude by providing reasoning on the impact and positivity of reducing production and consumption on the environment, resulting in a productive and progressive Japan for the near and long term future.

Keywords: eco-system, resource productivity, sound material-cycle, sustainable development

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Authors: Solomon Huluka, Akrum Abdul-Latif, Rachid Baleh

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Metal foams have been developed intensively as a new class of materials for the last two decades due to their unique structural and multifunctional properties. The aim of this experimental work was to characterize the effect of biaxial loading complexity (combined compression-torsion) on the plastic response of highly uniform architecture open-cell aluminum foams of spherical porous with a density of 80%. For foam manufacturing, the Kelvin cells model was used to generate the generally spherical shape with a cell diameter of 11 mm. A patented rig called ACTP (Absorption par Compression-Torsion Plastique), was used to investigate the foam response under quasi-static complex loading paths having different torsional components (i.e. 0°, 45° and 60°). The key mechanical responses to be examined are yield stress, stress plateau, and energy absorption capacity. The collapse mode was also investigated. It was concluded that the higher the loading complexity, the greater the yield strength and the greater energy absorption capacity of the foam. Experimentally, it was also noticed that there were large softening effects that occurred after the first pick stress for both biaxial-45° and biaxial-60° loading.

Keywords: aluminum foam, loading complexity, characterization, biaxial loading

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Authors: Watchawin Ekphinitphithaya, Patompong Satapornpong

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Introduction: Carbamazepine (CBZ) is one of the most prescribed antiepileptic drugs (AEDs) by neurologists and non-neurologist worldwide. CBZ is usually prescribed along with other drugs, leading to the possibility of severe cutaneous adverse drug reactions (SCARs). The HLA-B*15:02 is strongly associated with CBZ-induced Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS–TEN) in the Han Chinese and other Asian populations but not in European populations, while HLA-A*31:01 allele has been reported to be associated with CBZ-induced SCARs in European population and Japanese. Objective: The aim of this study is to investigate the distribution of pharmacogenetics HLA-A*31:01 marker in a healthy Thai population associated with Carbamazepine-induced SCARs. Materials and Methods: Prospective study, 350 unrelated healthy Thais were recruited in this study. Human leukocyte antigen-A alleles were genotyped using PCR-sequence specific oligonucleotides (PCR-SSOs). Results: The frequency of HLA-A alleles were HLA-A*11:01 (190 alleles, 27.14%), HLA-A*24:02 (82 alleles, 11.71%), HLA-A*02:03 (80 alleles, 11.43%), HLA-A*33:03 (76 alleles, 10.86%), HLA-A*02:07 (58 alleles, 8.29%), HLA-A*02:01 (35 alleles, 5.00%), HLA-A*24:07 (29 alleles, 4.14%), HLA-A*02:06 – HLA-A*30:01 (15 alleles, 2.14%), and HLA-A*01:01 (14 alleles, 2.00%). Particularly, the number of HLA-A*31:01 alleles was 6 of 700 (0.86%) in the healthy Thai population. Many research presented varying distributions of HLA-A*31:01 in Asians, including 2% of Han Chinese, 9% of Japanese and 5% of Koreans. In addition, this allele was found approximately 2-5% in the Caucasian population. Conclusions: Thus, the pharmacogenetics database is vital to support in many populations, especially in Thais, for screening HLA-A*31:01 allele to avoid CBZ-induced SCARs before initiating treatments in each population.

Keywords: Carbamazepine, HLA-A*31:01, Thai population, pharmacogenetics

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Authors: N. Berrouachedi, M. Bouslama, S. Rioual, B. Lescop, J. Langlois

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Using first-principles calculations within the LSDA (Local Spin Density Approximation) method based on density functional theory (DFT), the electronic structure and magnetic properties of zinc blende Fe/In0.5Ga0.5As/InPsuperlattice are investigated. This compound are found to be half -metallic ferromagnets with a total magnetic moment of 2.25μB per Fe. In addition to this, we reported the DRX measurements of the thick iron sample before and after annealing. One should note, after the annealing treatment at a higher temperature, the disappearance of the peak associated to the Fe(001) plane. In contrast to this report, we observed after the annealing at low temperature the additional peaks attributed to the presence of indium and Fe2As. This suggests a subsequent process consisting in a strong migration of atoms followed with crystallization at the higher temperature.To investigate the origin of magnetism and electronic structure in these zb compounds, we calculated the total and partial DOS of FeInP.One can see that µtotal=4.24µBand µFe=3.27µB in contrast µIn=0.021µB and µP=0.049µB.These results predicted that FeInP compound do belong to the class of zb half metallic HM ferromagnetswith a pseudo gap= 0.93 eVare more promising materials for spintronics devices.

Keywords: zincblend structure, half metallic ferromagnet, spin moments, total and partial DOS, DRX, Wien2k

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Authors: Fathi Ali Swaid

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The CBR test is widely used in the assessment of granular materials in base, subbase and subgrade layers of road and airfield pavements. Despite the success of this method, but it depends on a limited numbers of soil samples. This limitation do not adequately account for the spatial variability of soil properties. Thus, assessment is derived using these cursory soil data are likely to contain errors and thus make interpretation and soil characterization difficult. On the other hand quantitative methods of soil inventory at the field scale involve the design and adoption of sampling regimes and laboratory analysis that are time consuming and costly. In the latter case new technologies are required to efficiently sample and observe the soil in the field. This is particularly the case where soil bearing capacity is prevalent, and detailed quantitative information for determining its cause is required. In this paper, an electrical resistivity method DC is described and its application in Elg'deem Dirt road, located in Gasser Ahmad - Misurata, Libya. Results from the DC instrument were found to be correlated with the CBR values (r2 = 0.89). Finally, it is noticed that, the correlation can be used with experience for determining CBR value using basic soil electrical resistivity measurements and checked by few CBR test representing a similar range of CBR.

Keywords: California bearing ratio, basic soil electrical resistivity, CBR, soil, subgrade, new technologies

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Authors: N. Flores-Martinez, G. Franceschin, T. Gaudisson, J.-M. Greneche, R. Valenzuela-Monjaras, S. Ammar

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Tailoring bulk materials keeping their nanoscale properties is the daydream of material scientists. But especially in magnetism, this single desire can revolutionize our everyday life. Now, thanks to the methods of synthesis, based on the combination of colloidal chemistry (CC) to flash sintering (FS), customizing magnets becomes each time more 'easy', 'cheap' and 'clean'. Although by CC we can obtain straightway nanopowders with good magnetic featuring, like exchange bias (EB) phenomenon, it does not result so attractive for applications. Since a solid material is simple to manipulate and integrate in a device, many consolidation methods have been tested aiming to keep the nanopowders characteristics after consolidation. Unfortunately, the lack of structural crystalline arrangement and the grain growth worsen the magnetic properties. In this work, we exhibit, for the first-time author’s best knowledge, the EB in sintered ceramics, starting from CoFe₂O₄-core@CoO-shell NPs obtained by CC. Despite the fact that EB field is about 28 mT in ceramics and it is not yet considered for applications, this work opens an alternative in the permanent magnets fabrication through a FS method, the spark plasma sintering, starting from CC synthesized nanopowders.

Keywords: core-shell nanoparticles, exchange bias, nanostructured ceramics, spark plasma sintering

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Authors: Sidi Mohamed Mesli, Mohamed Habchi, Mohamed Kotbi, Rafik Benallal, Abdelali Derouiche

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Fluoride glasses with a nominal composition of BaMnMF7 (M = FeV assuming isomorphous replacement) have been structurally modelled through the simultaneous simulation of their neutron diffraction patterns by a reverse Monte Carlo (RMC) model and by a Rietveld for disordered materials (RDM) method. Model is consistent with an expected network of interconnected [MF6] polyhedra. The RMC results are accompanied by artificial satellite peaks. To remedy this problem, we use an extension of the RMC algorithm, which introduces an energy penalty term in acceptance criteria. This method is called the Hybrid Reverse Monte Carlo (HRMC) method. The idea of this paper is to apply the (HRMC) method to the title glasses, in order to make a study of the phenomenon nature of order and disorder by displaying and discussing the partial pair distribution functions (PDFs) g(r). We suggest that this method can be used to describe average correlations between components of fluoride glass or similar system.

Keywords: fluoride glasses, RMC simulation, neutron scattering, hybrid RMC simulation, Lennard-Jones potential, partial pair distribution functions

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Authors: Marianna I. Triantou, Petroula A. Tarantili

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In this research work, poly (acrylonitrile-butadiene-styrene)/polypropylene (ABS/PP) blends were processed by melt compounding in a twin-screw extruder. Upgrading of the thermal characteristics of the obtained materials was attempted by the incorporation of organically modified montmorillonite (OMMT), as well as, by the addition of two types of compatibilizers; polypropylene grafted with maleic anhydride (PP-g-MAH) and ABS grafted with maleic anhydride (ABS-g-MAH). The effect of the above treatments was investigated separately and in combination. Increasing the PP content in ABS matrix seems to increase the thermal stability of their blend and the glass transition temperature (Tg) of SAN phase of ABS. From the other part, the addition of ABS to PP promotes the formation of its β-phase, which is maximum at 30 wt% ABS concentration, and increases the crystallization temperature (Tc) of PP. In addition, it increases the crystallization rate of PP.The β-phase of PP in ABS/PP blends is reduced by the addition of compatibilizers or/and organoclay reinforcement. The incorporation of compatibilizers increases the thermal stability of PP and reduces its melting (ΔΗm) and crystallization (ΔΗc) enthalpies. Furthermore it decreases slightly the Tgs of PP and SAN phases of ABS/PP blends. Regarding the storage modulus of the ABS/PP blends, it presents a change in their behavior at about 10°C and return to their initial behavior at ~110°C. The incorporation of OMMT to no compatibilized and compatibilized ABS/PP blends enhances their storage modulus.

Keywords: acrylonitrile, butadiene, styrene terpolymer, compatibilizer, organoclay, polypropylene

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Authors: Ekenyem Stan Chinweike

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The suitability of some clay deposits in south eastern Nigeria (Unwana, Ekebedi and Nsu) as materials for the production of floor tiles was investigated. The clay samples were analyzed using wet classical method to determine their chemical composition. Floor tile test specimens were produced using standard method. The test specimens were tested for physical properties such as compressive strength and porosity at 1050◦c and 1150◦c temperature levels. The chemical analysis showed the following results: Unwana (5102 52.24%, AL2o3, 27.20%, Fe2o3 7%, T102 (1.52%), Ekebedi (S102 (58.53%), Al2o3 28.42%, Fe2o3 7%, Ti o2 (1.12%),NSU SIo2 (58.16%), Al2O3 (28.42%), Fe2O3 1.89%, T102 (0.82%) The compressive strength of Unwana, Ekebedi and Nsu clays at 1050◦c are respectively: 15MPa, 13.75MPa and 13.5MPa. At 1150◦c, the values are 16.2MPa and 16.0MPa for Ekebedi and Nsu clays respectively. The porosity of Unwana, Ekebedi and Nsu clays at 1050◦c are respectively31.57%, 23.15% and 24.21%. At 1150◦c, the values are 23.65% and 24.75% for Ekebedi and Nsu respectively. The three clays can be used for production of tiles but Ekebedi has the highest compressive strength which makes it the most suitable clay for the production of floor tiles when compared with floor tiles of the same nominal size stipulated by ASTM standard.

Keywords: feldspar, quartz, porosity, compressive strength, clay minerals

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Authors: Livia Eisler, Cristiane C. B. Alves, Cristina L. F. Ortolani, Kurt Faltin Jr.

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Purpose: This paper proposes a technically simple diagnosis method among orthodontists and maxillofacial surgeons in order to evaluate discrete bone alterations. The methodology consists of a protocol to optimize the diagnosis and minimize the possibility for orthodontic and ortho-surgical retreatment. Materials and Methods: A protocol of image processing and analysis, through ImageJ software and its plugins, was applied to 20 pairs of lateral cephalometric images obtained from cone beam computerized tomographies, before and 1 year after undergoing orthognathic surgery. The optical density of the images was analyzed in the condylar region to determine possible bone alteration after surgical correction. Results: Image density was shown to be altered in all image pairs, especially regarding the condyle contours. According to measures, condyle had a gender-related density reduction for p=0.05 and condylar contours had their alterations registered in mm. Conclusion: A simple, viable and cost-effective technique can be applied to achieve the more detailed image-based diagnosis, not depending on the human eye and therefore, offering more reliable, quantitative results.

Keywords: bone resorption, computer-assisted image processing, orthodontics, orthognathic surgery

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Authors: Chisakan Papapankiad

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The purposes of this research were 1) to study the competency of condominium managers, 2) to create the training curriculum via electronic media for condominium managers, and 3) to evaluate the training curriculum for condominium managers. The research methods included document analysis, interview, questionnaire, and a try-out. A total of 20 experts were selected to collect data by using Delphi technique. The designed curriculum was tried out with 30 condominium managers. The important steps of conducting this research included analyzing and synthesizing, creating interview questions, conducting factor analysis and developing the training curriculum, editing by experts, and trying out with sample groups. The findings revealed that there were five core competencies: leadership, human resources management, management, communication, and self-development. The training curriculum was designed and all the learning materials were put into a CD. The evaluation of the training curriculum was performed by five experts and the training curriculum was found to be cohesive and suitable for use in the real world. Moreover, the findings also revealed three important issues: 1) the competencies of the respondents after the experiment were higher than before the experiment and this had a level of significance of 0.01, 2) the competencies remained with the respondents at least 12 weeks and this also had a level of significance of 0.01, and 3) the overall level of satisfaction from the respondents were 'the highest level'.

Keywords: competency training curriculum, condominium managers, electronic media

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Authors: Mohit Kalra, Varun S., Mayuri Gandhi

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CeF3 nanophosphors has been extensively investigated in the recent years for lighting and numerous bio-applications. Down conversion emissions in CeF3:Eu3+/Tb3+ phosphors were studied with the aim of obtaining a white light emitting composition, by a simple co-precipitation method. The material was characterized by X-ray Diffraction (XRD), High Resolution Transmission Electron Microscopy (HR-TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Photoluminescence (PL). Uniformly distributed nanoparticles were obtained with an average particle size 8-10 nm. Different doping concentrations were performed and fluorescence study was carried out to optimize the dopants concentration for maximum luminescence intensity. The steady state and time resolved luminescence studies confirmed efficient energy transfer from the host to activator ions. Different concentrations of Tb 3+, Eu 3+ were doped to achieve a white light emitting phosphor for UV-based Light Emitting Diodes (LEDs). The nanoparticles showed characteristic emission of respective dopants (Eu 3+, Tb3+) when excited at the 4f→5d transition of Ce3+. The chromaticity coordinates for these samples were calculated and the CeF3 doped with Eu 3+ and Tb3+ gave an emission very close to white light. These materials may find its applications in optoelectronics and various bio applications.

Keywords: white light down-conversion, nanophosphors, LEDs, rare earth, cerium fluoride, lanthanides

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Authors: T. Giansetto, E. Pierrot, P. Picavet, M. Lefebvre, S. Claeys, M. Balligand

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Objective: To test the low sensitivity of the Allberg and Miles index to the stifle opening angle, to evaluate the displacement of the patella after a Modified Maquet Technique using this index, and to assess the incidence of patella luxation post-Modified Maquet Technique in dogs. Materials and methods: Medical records were reviewed from 2012 to 2017. Allberg Miles index was determined for each stifle pre and post-operatively, as well as the stifle joint opening of each case. The occurrence of patella luxation was recorded. Results: 137 stifles on 116 dogs were reviewed. The stifle opening angle did not influence the Allberg Miles index (p=0.41). Pre and post-operative index showed a distal displacement of the patella after a Modified Maquet Procedure, especially at a 90° of stifle opening angle. Only 1/137 cases demonstrated patella luxation after the surgery. Conclusion: The Allberg Miles radiographic index is largely independent of the stifle opening angle and can be used to assess the proximo-distal position of the patella in relation to the femoral trochlear groove. If patella baja is clearly induced by the Modified Maquet Technique, the latter does not seem to predispose patients to post-operative patella luxation in a large variety of dog breeds.

Keywords: rlca, modified Maquet technique, patella luxation, orthopedic

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Authors: Daniela Istrati, Alina Morosan, Maria Stanca, Bogdan Purcareanu, Adrian Fudulu, Laura Olariu, Alice Buteica, Ion Mindrila, Rodica Cristescu, Dan Eduard Mihaiescu

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Our present work is related to the synthesis, characterization and applications of new nanocomposite materials based on silica mesoporous nanocompozites systems. The nanocomposite support was obtained by using a specific step–by–step multilayer structure buildup synthetic route, characterized by XRD (X-Ray Difraction), TEM (Transmission Electron Microscopy), FT-IR (Fourier Transform-Infra Red Spectrometry), BET (Brunauer–Emmett–Teller method) and loaded with Salvia officinalis plant extract obtained by a hydro-alcoholic extraction route. The sustained release of the target compounds was studied by a modified LC method, proving low release profiles, as expected for the high specific surface area support. The obtained results were further correlated with the in vitro / in vivo behavior of the nanocomposite material and recommending the silica mesoporous nanocomposites as good candidates for biomedical applications. Acknowledgements: This study has been funded by the Research Project PN-III-P2-2.1-PTE-2016-0160, 49-PTE / 2016 (PROZECHIMED) and Project Number PN-III-P4-ID-PCE-2016-0884 / 2017.

Keywords: biomedical, mesoporous, nanocomposites, natural products, sustained release

Procedia PDF Downloads 222

Authors: Rosli Mohd Yunus, A. K. M. Moshiul Alam, Mohammad Dalour Beg

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In the case of advance polymeric materials reinforcement and thermal stability of matrix is a focused arena of researchers. The distribution of carbon nanotubes (CNTs) in polymer matrix influences material properties. In this study, multi-walled carbon nanotubes (MWCNTs) have been dispersed in unsaturated polyester resin (UPR) through solution mixing and sonication techniques using tetra hydro furan (THF) solvent. Nanocomposites have been fabricated with solution mixing and without solution mixing. Viscosity, Fourier-transform infrared spectroscopy, Field emission scanning electron microscopy (FESEM) investigations have been conducted to study the distribution as well as interaction between matrix and MWCNT. The differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and pyrolysis behavior have been conducted to study the thermal degradation and stability of nanocomposites. In addition, the SEM micrographs of nanocomposite residual chars were exhibited more packed together. Incorporation of CNT enhances crystallinity and mechanical and thermal properties of the nanocomposites. Correlations among MWCNTs dispersion, nucleation, fracture morphology and various properties have been made.

Keywords: char, multiwall carbon nanotubes, nano composite, pyrolysis

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Authors: Christina Kalogirou

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Investigating the integration of bioclimatic design into vernacular architecture could lead to interesting results regarding the preservation of cultural heritage while enhancing the energy efficiency of historic buildings. Furthermore, these recognized principles and systems of bioclimatic design in vernacular settlements could be applied to modern architecture and thus to new buildings in such areas. This study introduces an approach to categorizing distinct technologies and design principles of bioclimatic design based on a thoughtful approach to various climatic zones and environment in Greece (mountainous areas, islands and lowlands). For this purpose, various types of dwellings are evaluated for their response to climate, regarding the layout of the buildings (orientation, floor plans’ shape, semi-open spaces), the site planning, the openings (size, position, protection), the building envelope (walls: construction materials-thickness, roof construction detailing) and the migratory living pattern according to seasonal needs. As a result, various passive design principles (that could be adapted to current architectural practice in such areas, in order to optimize the relationship between site, building, climate and energy efficiency) are proposed.

Keywords: bioclimatic design, buildings physics, climatic zones, energy efficiency, vernacular architecture

Procedia PDF Downloads 390

Authors: Nadia Nisha Musa, Nur Atirah Hasmi, Hasnun Nita Ismail, Zulfadli Mahfodz

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In Malaysian Education System, subject related to biodiversity has started in the curriculum from Foundation Study until tertiary education. Biodiversity become the focus of attention due to awareness on global warming which potentially leads to a loss of biodiversity. A loss in biodiversity means a loss in medicinal discoveries and reduces food supply. It is of great important to ensure that young generations become aware of biodiversity conservation. The more interactive approaches are needed to build society with a high awareness for biodiversity conservation. To address this challenge, the goal of this study is to enhance intrinsic motivation of biological students via ARCS model of instruction. Self-access learning materials such as tutorial, module and fieldwork were designed with ARCS elements to a sample size of 70 university students from the beginning of the semester. Both paper and online surveys were used to collect data from the respondents. The results showed that elements of attention, relevance, confidence and satisfaction have a positive impact on intrinsic motivation of students and their academic performance.

Keywords: intrinsic motivation, ARCS model of instruction, biodiversity, self-access learning

Procedia PDF Downloads 224

Authors: Adesola O. Orimoloye, Edward Gobina

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Membrane separation technology is still considered as an emerging technology in the mining sector and does not yet have the widespread acceptance that it has in other industrial sectors. Underground Coal Gasification (UCG), wherein coal is converted to gas in-situ, is a safer alternative to mining method that retains all pollutants underground making the process environmentally friendly. In-situ combustion of coal for power generation allows access to more of the physical global coal resource than would be included in current economically recoverable reserve estimates. Where mining is no longer taking place, for economic or geological reasons, controlled gasification permits exploitation of the deposit (again a reaction of coal to form a synthesis gas) of coal seams in situ. The oxygen supply stage is one of the most expensive parts of any gasification project but the use of membranes is a potentially attractive approach for producing oxygen-enriched air. In this study, a variety of cost-effective membrane materials that gives an optimal amount of oxygen concentrations in the range of interest was designed and tested at diverse operating conditions. Oxygen-enriched atmosphere improves the combustion temperature but a decline is observed if oxygen concentration exceeds optimum. Experimental result also reveals the preparatory method, apparatus and performance of the fabricated membrane.

Keywords: membranes, oxygen-enrichment, gasification, coal

Procedia PDF Downloads 463