Search results for: scheelite BaWO4 phase

Authors: A. Baqqal, O. Abduhamid, H. Abdul-Hameed, T. Messager, G. Ayoub

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In this contribution, the effect of crystal content on the cyclic response of semi-crystalline polyethylene is studied over a large strain range. Experimental observations on a high-density polyethylene with 72% crystal content and an ultralow density polyethylene with 15% crystal content are reported. The cyclic stretching does appear a thermoplastic-like response for high crystallinity and an elastomeric-like response for low crystallinity, both characterized by a stress-softening, a hysteresis and a residual strain, whose amount depends on the crystallinity and the applied strain. Based on the experimental observations, a unified viscoelastic-viscoplastic constitutive model capturing the polyethylene cyclic response features is proposed. A two-phase representation of the polyethylene microstructure allows taking into consideration the effective contribution of the crystalline and amorphous phases to the intermolecular resistance to deformation which is coupled, to capture the strain hardening, to a resistance to molecular orientation. The polyethylene cyclic response features are captured by introducing evolution laws for the model parameters affected by the microstructure alteration due to the cyclic stretching.

Keywords: cyclic loading unloading, polyethylene, semi-crystalline polymer, viscoelastic-viscoplastic constitutive model

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Authors: Timothy J. Grebec

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This study investigated whether using a voice dictation software program (i.e., Google Voice Typing) has an impact on student writing quality. The research took place in a third-grade general education classroom in a suburban school setting. Because the study involved minors, all data was encrypted and deidentified before analysis. The students completed a series of writings prior to the beginning of the intervention to determine their thoughts and skill level with writing. During the intervention phase, the students were introduced to the voice dictation software, given an opportunity to practice using it, and then assigned writing prompts to be completed using the software. The prompts written by nineteen student participants and surveys of student opinions on writing established a baseline for the study. The data showed that using the dictation software resulted in a 34% increase in the response quality (compared to the Pennsylvania State Standardized Assessment [PSSA] writing guidelines). Of particular interest was the increase in students' proficiency in demonstrating mastery of the English language and conventions and elaborating on the content. Although this type of research is relatively no, it has the potential to reshape the strategies educators have at their disposal when instructing students on written language.

Keywords: educational technology, accommodations, students with disabilities, writing instruction, 21st century education

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Authors: M. Sumida, S. Morita

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In this research, the effect of unsteady flows acting on road vehicles was experimentally investigated, using an advanced and recently introduced wind tunnel. The aims of this study were to extract the characteristics of fluid forces acting on road vehicles under unsteady wind conditions and obtain new information on drag forces in a practical on-road test. We applied pulsating wind as a representative example of the atmospheric fluctuations that vehicles encounter on the road. That is, we considered the case where the vehicles are moving at constant speed in the air, with large wind oscillations. The experimental tests were performed on the Ahmed-type test model, which is a simplified vehicle model. This model was chosen because of its simplicity and the data accumulated under steady wind conditions. The experiments were carried out with a time-averaged Reynolds number of Re = 4.16x10⁵ and a pulsation period of T = 1.5 s, with amplitude of η = 0.235. Unsteady fluid forces of drag and lift were obtained utilizing a multi-component load cell. It was observed that the unsteady aerodynamic forces differ significantly from those under steady wind conditions. They exhibit a phase shift and an enhanced response to the wind oscillations. Furthermore, their behavior depends on the slant angle of the rear shape of the model.

Keywords: Ahmed body, automotive aerodynamics, unsteady wind, wind tunnel test

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Authors: Sonjida Mustafia

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Glass-ceramic is a material that contains both the properties of glass and ceramic within. They always contain a residual glassy phase and one or more embedded crystalline phases. Ceramic tiles are very popular in the world because of their high structural strength, low absorption, increased hygiene, and hot and cold insulation. Glass-ceramic materials are used to produce marble-like floor and wall tiles. There are a huge amount of waste materials like rice husk ash (RHA), waste iron, waste glass, and other industrial solid waste in Bangladesh, which can be used to produce glass-ceramic floor and wall tiles. The raw materials (rice husk ash, waste glass, and k-feldspar) are a mixture, and the mixture is melted to form glass frit at 1175°C. The frits are grained to require fine particle size. The powder is moistened in 7-8% water with sodium silicate. The green glass-ceramic tiles were fired at different temperatures (800–1100°C) for a soaking time of 1 hour to form glass-ceramic tiles and to study the sintering-crystallization process. The results reveal that the modulus of rupture increases with increasing sintering temperature and reaches the highest value (95.25Mpa) at 925°C. Glossiness and linear shrinkage increase with increasing temperature.

Keywords: rice husk ash, waste glass, glass-ceramic, modulus of rupture, glossiness, linear shrinkage, micro-structure

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Authors: Emre Akyürek, Anthony Huynh, Tatiana Kalganova

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The Ambidextrous Robot Hand is a robotic device with the purpose to mimic either the gestures of a right or a left hand. The symmetrical behavior of its fingers allows them to bend in one way or another keeping a compliant and anthropomorphic shape. However, in addition to gestures they can reproduce on both sides, an asymmetrical mechanical design with a three tendons routing has been engineered to reduce the number of actuators. As a consequence, control algorithms must be adapted to drive efficiently the ambidextrous fingers from one position to another and to include grasping features. These movements are controlled by pneumatic muscles, which are nonlinear actuators. As their elasticity constantly varies when they are under actuation, the length of pneumatic muscles and the force they provide may differ for a same value of pressurized air. The control algorithms introduced in this paper take both the fingers asymmetrical design and the pneumatic muscles nonlinearity into account to permit an accurate control of the Ambidextrous Robot Hand. The finger motion is achieved by combining a classic PID controller with a phase plane switching control that turns the gain constants into dynamic values. The grasping ability is made possible because of a sliding mode control that makes the fingers adapt to the shape of an object before strengthening their positions.

Keywords: ambidextrous hand, intelligent algorithms, nonlinear actuators, pneumatic muscles, robotics, sliding control

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Authors: M. S. Agha, A. M. Eshahiry, S. A. Aldabbar, Z. M. Alshahri

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The propagation of microwave is affected by rain and dust particles by way of signal attenuation and de-polarization. Computations of these effects require knowledge of the propagation characteristics of microwave and millimeter wave energy in the climate conditions of the studied region. This paper presents the effect of wind and humidity on wireless communication such as microwave links in the west north region of Libya (Al-Khoms), experimental procedure to study the effects mentioned above. The experimental procedure is done on three selected antennae towers (Nagaza stations, Al-Khoms center stations, Al-Khoms gateway stations) to determining of the attenuation loss per unit length and cross-polarization discrimination (XPD) change which coverage in the studied region, it is required to collect the dust particles carried out by the wind, measure the particles size distribution (PSD), calculate the concentration, and carry chemical analysis of the contents, then the dielectric constant can be calculated. The result showed that effect of the humidity and dust, the antenna height, the visibility, on the complex permittivity effects both attenuation and phase shift, there is some consideration that has to be taken into account in the communication power budget.

Keywords: attenuation, de-polarization, scattering, transmission loss

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Authors: Surajit Chattopadhyay

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Accelerated expansion of the current universe is well-established in the literature. Dark energy and modified gravity are two approaches to account for this accelerated expansion. In the present work, we consider scalar field models of dark energy, namely, tachyon and DBI essence in the framework of chameleon Brans-Dicke cosmology. The equation of state parameter is reconstructed and the subsequent cosmological implications are studied. We examined the stability for the obtained solutions of the crossing of the phantom divide under a quantum correction of massless conformally invariant fields and we have seen that quantum correction could be small when the phantom crossing occurs and the obtained solutions of the phantom crossing could be stable under the quantum correction. In the subsequent phase, we have established a correspondence between the NHDE model and the quintessence, the DBI-essence and the tachyon scalar field models in the framework of chameleon Brans–Dicke cosmology. We reconstruct the potentials and the dynamics for these three scalar field models we have considered. The reconstructed potentials are found to increase with the evolution of the universe and in a very late stage they are observed to decay.

Keywords: dark energy, holographic principle, modified gravity, reconstruction

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Authors: Monireh Azimi, Mohammad Reza Toroghinejad, Leo A. I. Kestens

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The role of different metallic and intermetallic reinforcements on the microstructure and the associated mechanical response of a composite is of crucial importance. To investigate this issue, a multiphase metal-intermetallic composite was in-situ fabricated through reactive annealing and accumulative roll bonding (ARB) processes. EBSD results indicated that the lamellar grain structure of the Al matrix after the first cycle has evolved with increasing strain to a mixed structure consisting of equiaxed and lamellar grains, whereby the steady-state did not occur after the 3rd (last) cycle—applying a strain of 6.1 in the Al phase, the length and thickness of the grains reduced by 92.2% and 97.3%, respectively, compared to the annealed state. Intermetallic phases together with the metallic reinforcement of Ni influence grain fragmentation of the Al matrix and give rise to a specific texture evolution by creating heterogeneity in the strain and flow patterns. Mechanical properties of the multiphase composite demonstrated the yield and ultimate tensile strengths of 217.9 MPa and 340.1 MPa, respectively, compared to 48.7 MPa and 55.4 MPa in the metal-intermetallic laminated (MIL) sandwich before applying the ARB process, which corresponds to an increase of 347% and 514% of yield and tensile strength, respectively.

Keywords: accumulative roll bonding, mechanical properties, metal-intermetallic composite, severe plastic deformation, texture

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Authors: Shoubhik Mandal, Debarghya Mallick, Abhishek Banerjee, R. Ganesan, P. S. Anil Kumar

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We report magnetotransport measurements in Bi₁Sb₁Te₁.₅Se₁.₅/RuCl₃ heterostructure nanodevices. Bi₁Sb₁Te₁.₅Se₁.₅ (BSTS) is a strong three-dimensional topological insulator (3D-TI) that hosts conducting topological surface states (TSS) enclosing an insulating bulk. α-RuCl₃ (namely, RuCl₃) is an anti-ferromagnet that is predicted to behave as a Kitaev-like quantum spin liquid carrying Majorana excitations. Temperature (T)-dependent resistivity measurements show the interplay between parallel bulk and surface transport channels. At T < 150 K, surface state transport dominates over bulk transport. Multi-channel weak anti-localization (WAL) is observed, as a sharp cusp in the magnetoconductivity, indicating strong spin-orbit coupling. The presence of top and bottom topological surface states (TSS), including a pair of electrically coupled Rashba surface states (RSS), are indicated. Non-linear Hall effect, explained by a two-band model, further supports this interpretation. Finally, a low-T logarithmic resistance upturn is analyzed using the Lu-Shen model, supporting the presence of gapless surface states with a π Berry phase.

Keywords: topological materials, electrical transport, Lu-Shen model, quantum spin liquid

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Authors: Megan E. Davies

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As substance use become an increasing prevalent occurrence amongst young people, prevention programs designed specifically for children and adolescents are required to protect against associated cognitive, psychological, and behavioural issues. Further, young people from marginalized backgrounds would highly benefit from culturally adapted substance use prevention programs. The first and second phase of the Life Skills Training (LST) program, the Maskwacis Life Skills Training (MLST) program, the Bii-Zin-Da-De-Da (BZDDD; “Listening to One Another”), and a culturally sensitive smoking prevention program, all of which have been adapted to Canadian Indigenous cultures and are applied within the school and family settings, are discussed. Additionally, comorbid disorders, at-risk personality types, and motivating factors associated with substance use amongst Canadian children and adolescents, specifically Indigenous youth, are explored through the application of a biopsychosocial model. Requital efforts being made in Canada towards Indigenous communities are described within a historical context, and substance use prevention programs targeting Indigenous children and adolescents are compared. Through this lens, suggestions are presented for future research on preventative interventions directed towards substance use within minority groups.

Keywords: early intervention, cultural appropriateness, life skills training, smoking prevention, drug and alcohol prevention

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Authors: Raluca Ionela Maxim

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Designing a gender responsive Science, Technology, Engineering and Mathematics (STEM) mobile game based learning solution (mGBL) is a challenge in terms of content, gamification level and equal engagement of girls and boys. The goal of this case study was to research and create a high-fidelity prototype design of a mobile game that contains role-models as avatars that guide and expose girls and boys to STEM learning content. For this research purpose it was applied the methodology of design sprint with five-phase process that combines design thinking principles. The technique of this methodology comprises smart interviews with STEM experts, mind-map creation, sketching, prototyping and usability testing of the interactive prototype of the gender responsive STEM mGBL. The results have shown that the effect of the avatar/role model had a positive impact. Therefore, by exposing students (boys and girls) to STEM role models in an mGBL tool is helpful for the decreasing of the gender inequalities in STEM fields.

Keywords: design thinking, design sprint, gender-responsive STEM education, mobile game based learning, role-models

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Authors: Chaoqun Zhao, Gang Fang

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Twinning is an important deformation mechanism of magnesium alloys, but there is no consensus on the relationship between twinning and ductility. To comprehensively understand the effect of twinning on plastic deformation and cracking, the in situ tensile tests of a magnesium alloy sample along its extrusion direction were conducted, accompanied by the observations using scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD). The misorientation angles around specific axes and trace analysis of grains were used to identify the active twinning systems. The results show that the area fraction of tension twins increases with the increasing strain, resulting in the c-axes of most grains rotating from the normal direction to the transverse direction, and the intensity of (0002) pole is weakened. Based on the analysis of kernel average misorientation (KAM) and SEM maps, it is found that the appearance of tension twins accommodates plastic deformation. However, the stress concentration caused by the intersection of tension twinning with the second phase can lead to crack initiation, and the crack propagates along the direction perpendicular to the tension twinning. For contraction twinning, it plays a role in plastic relaxation and improving strain compatibility during deformation, and is not a necessary potential mechanism of crack nucleation.

Keywords: magnesium alloy, cracking, in-situ EBSD, twinning

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Authors: M. Fowsia, Dominic Xavier Fernando, Vinojitha, Rahamath Juliyana

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Aerofoil is a primary element to be designed during the initial phase of creating any new aircraft. It is the component that forms the cross-section of the wing. The wing is used to produce lift force that balances the weight which is acting downwards. The lift force is created due to pressure difference over the top and bottom surface which is caused due to velocity variation. At sub-sonic velocities, for a real fluid, we obtain a smooth flow of air over both the surfaces. In this era of high speed travel, commercial aircraft that can travel faster than speed of sound barrier is required. However transonic velocities cause the formation of shock waves which can cause flow separation over the top and bottom surfaces. In the transonic range, shock waves move across the top and bottom surfaces of the aerofoil, until both the shock waves merge into a single shock wave that is formed near the leading edge of theaerofoil. In this paper, a transonic aerofoil is designed and its aerodynamic properties at different velocities in the Transonic range (M = 0.8; 0.9; 1; 1.1; 1.2) are studied with the help of CFD. The Pressure and Velocity distributions over the top and bottom surfaces of aerofoil are studied and the variations of shock patterns, at different velocities, are analyzed. The analysis can be used to determine the effect of drag divergence on the lift created by the aerofoil.

Keywords: transonic aerofoil, cfd, drag divergence, shock formation, viscous flow

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Authors: Mehdi Ghatus

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Two simple apparatus based on the hammer and anvil principle have been constructed and used to study the microstructure and micro-hardness characteristics of some AL-base alloys. Foils with thicknesses arranging from 20 µm up to 600 µm have been obtained. The cooling rate was estimated to be in the range 10^4 - 10^5 K/sec. Microstructure study of rapidly quenched Al-30% Si foils indicated that with decreasing the foil thickness the size of primary Si crystallites decreases in the whole investigated range (0.64-0.15 mm). However, the volume fraction of the primary Si crystals in the structure remained constant down to thickness the primary Si volume fraction started to decrease. Rapid quenching of Al- 14-16% Cu showed single phase cell structure. In foils up to 0.55 mm with decreasing the foil thickness the cell size decreases and micro-hardness increases particularly in foils below 0.3 mm in thickness. Isochronal annealing of theses foils show that the highly supersaturated Al-14-16% Cu solid solution decomposes readily at relatively low temperature and short time intervals. The maximum hardness is obtained after annealing at 100 °C for 30 minutes. However with decreasing the Cu content of the foils the precipitation process is largely delayed. Eight hours of annealing at 100 °C was not enough to achieve the maximum hardness in Al-4% Cu thin foils. The achieved hardness value was more than twice of the maximum hardness obtained in articles of similar composition but conventionally aged.

Keywords: aluminum, hardness, alloys, quenched aluminum

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Authors: Sophie Herr, Antoine Leybros, Yves Barre, Sergey Nikitenko, Rachel Pflieger

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The proportion of soil contaminated by a wide range of pollutants (heavy metals, PCBs, pesticides, etc.) of anthropogenic origin is constantly increasing, and it is becoming urgent to address this issue. Among remediation methods, soil washing is an effective, relatively fast, and widely used process. This study assesses its coupling with ultrasound: indeed, sonication induces the formation of cavitation bubbles in solution that enhance local mass transfer through agitation and particle erosion. The removal of target toxic elements Ni(II) and Zn(II) from vermiculite clay has been studied under 20 kHz ultrasound and silent conditions. Several acids were tested, and HCl was chosen as the solvent. The effects of solid/liquid ratio and particle size were investigated. Metal repartition in the clay has been followed by Tessier's sequential extraction procedure. The results showed that more metal elements bound to the challenging residual phase were desorbed with 20 kHz ultrasound than in silent conditions. This supports the promising application of ultrasound for heavy metal desorption in difficult conditions. Further experiments were performed at high-frequency US (362 kHz), and it was shown that fragmentation of the vermiculite particles is then limited, while positive effects of US in the decontamination are kept.

Keywords: desorption, heavy metals, ultrasound, vermiculite

Procedia PDF Downloads 146

Authors: Karishma Chester, Sarvesh Paliwal, Sayeed Ahmad

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Solanumnigrum L. (Family: Solanaceae), is an important Indian medicinal plant and have been used in various traditional formulations for hepato-protection. It has been reported to contain significant amount of steroidal glycosides such as solamargine and solasonine as well as their aglycone part solasodine. Being important pharmacologically active metabolites of several members of Solanaceae these markers have been attempted various times for their extraction and quantification but separately for glycoside and aglycone part because of their opposite polarity. Here, we propose for the first time simultaneous extraction and quantification of aglycone (solasodine)and glycosides (solamargine and solasonine) inleaves and berries of S.nigrumusing solvent extraction followed by HPTLC analysis. Simultaneous extraction was carried out by sonication in mixture of chloroform and methanol as solvent. The quantification was done using silica gel 60F254HPTLC plates as stationary phase and chloroform: methanol: acetone: 0.5 % ammonia (7: 2.5: 1: 0.4 v/v/v/v) as mobile phaseat 400 nm, after derivatization with an isaldehydesul furic acid reagent. The method was validated as per ICH guideline for calibration, linearity, precision, recovery, robustness, specificity, LOD, and LOQ. The statistical data obtained for validation showed that method can be used routinely for quality control of various solanaceous drugs reported for these markers as well as traditional formulations containing those plants as an ingredient.

Keywords: solanumnigrum, solasodine, solamargine, solasonine, quantification

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Authors: Seyed Hassan Moosa-kazemi, Jalal Mohammadi Soleimani, Hassan Vatandoost, Mohammad Hassan Shirazi, Sara Hajikhani, Roonak Bakhtiari, Morteza Akbari, Siamak Hydarzadeh

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Malaria is an infectious disease and considered most important health problems in the southeast of Iran. Iran is elimination malaria phase and new tool need to vector control. Paraterasgenesis is a new way to cut of life cycle of the malaria parasite. In this study, the microflora of the surface and gut of various stages of Anopheles fluviatilis James as one of the important malaria vector was studied using biochemical and molecular techniques during 2013-2014. Twelve bacteria species were found including; Providencia rettgeri, Morganella morganii, Enterobacter aerogenes, Pseudomonas oryzihabitans, Citrobacter braakii، Citrobacter freundii، Aeromonas hydrophila، Klebsiella oxytoca, Citrobacter koseri, Serratia fonticola، Enterobacter sakazakii and Yersinia pseudotuberculosis. The species of Alcaligenes faecalis, Providencia vermicola and Enterobacter hormaechei were identified in various stages of the vector and confirmed by biochemical and molecular techniques. We found Providencia rettgeri proper candidate for paratransgenesis.

Keywords: Anopheles fluviatilis, bacteria, malaria, Paraterasgenesis, Southern Iran

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Authors: Armando Cartenì, Ilaria Henke

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Recently, the Italian government has approved a new law for public contracts and has been laying the groundwork for restarting a planning phase. The government has adopted the indications given by the European Commission regarding the estimation of the external costs within the Cost-Benefit Analysis, and has been approved the ‘Guidelines for assessment of Investment Projects’. In compliance with the new Italian law, the aim of this research was to perform a feasibility study applying quantitative methods regarding the revamping of an Italian tourist railway line. A Cost-Benefit Analysis was performed starting from the quantification of the passengers’ demand potentially interested in using the revamped rail services. The benefits due to the external costs reduction were also estimated (quantified) in terms of variations (with respect to the not project scenario): climate change, air pollution, noises, congestion, and accidents. Estimations results have been proposed in terms of the Measure of Effectiveness underlying a positive Net Present Value equal to about 27 million of Euros, an Internal Rate of Return much greater the discount rate, a benefit/cost ratio equal to 2 and a PayBack Period of 15 years.

Keywords: cost-benefit analysis, evaluation analysis, demand management, external cost, transport planning, quality

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Authors: A. Nguyen, K. Nguyen, J. Jackson, E. Manlapig

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With the recent advancement in core imaging systems, a large volume of high resolution drill core images can now be collected rapidly. This paper presents a method for rapid prediction of ore-specific breakage parameters from high resolution mineral classified core images. The aim is to allow for a rapid assessment of the variability in ore hardness within a mineral deposit with reduced amount of physical breakage tests. This method sees its application primarily in project evaluation phase, where proper evaluation of the variability in ore hardness of the orebody normally requires prolong and costly metallurgical test work program. Applying this image-based texture analysis method on mineral classified core images, the ores are classified according to their textural characteristics. A small number of physical tests are performed to produce a dataset used for developing the relationship between texture classes and measured ore hardness. The paper also presents a case study in which this method has been applied on core samples from a copper porphyry deposit to predict the ore-specific breakage A*b parameter, obtained from JKRBT tests.

Keywords: geometallurgy, hyperspectral drill core imaging, process simulation, texture analysis

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Authors: Amy Halseth, Kevin Shan, Kye Gilder, John Buse

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The study assessed the effect of prolonged-release naltrexone 32 mg/bupropion 360 mg (NB) on cardiovascular (CV) events in overweight/obese participants at elevated CV risk. Participants must lose ≥ 2% body weight at 16 wks, without a sustained increase in blood pressure, to continue drug. The study was terminated early after second interim analysis with 50% of all CV events. Data on CV endpoints has been published. Current analyses focus on weight change. Intent-to-treat (ITT) population (placebo [PBO] N=4450, NB N=4455) was 54.5% female, 83.5% white, mean age 61 yrs, mean BMI 37.3 kg/m2; 85.2% had type 2 diabetes, 32.1% had CV disease, 17.4% had both. At 52 wks, ITT-LOCF analysis showed greater least squares mean percent change in weight (LSM%ΔBW) with NB (-3.1%; 95% CI -4.8, -1.4) vs PBO (-0.3%; 95% CI -1.9, 1.4). Both groups demonstrated greater weight loss while on-treatment (NB [-7.3%], PBO [-3.9%]). Odds ratios of 5% and 10% weight loss were 3.3 and 4.1 (ITT-LOCF), respectively, in NB over PBO. At 104 wks, on-treatment LSM%ΔBW was -6.3% with NB (n=1137) vs -3.5% with PBO (n=741). Major reasons for NB withdrawal were adverse events (AE, 29%) and patient decision (21%), with GI disorders being the most common. Weight loss with NB in this study, in an older population predominantly with diabetes and elevated CV risk, was somewhat lower than that observed in overweight/obese participants without diabetes and similar to participants with diabetes in Phase 3 studies.

Keywords: contrave, mysimba, obesity, pharmacotherapy, weight loss

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Authors: H. Troudi, M. Ghiss, Z. Tourki, M. Ellejmi

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Packed columns of liquefied petroleum gas (LPG) consists of separating the liquid mixture of propane and butane to pure gas components by the distillation phenomenon. The flow of the gas and liquid inside the columns is operated by two ways: The co-current and the counter current operation. Heat, mass and species transfer between phases represent the most important factors that influence the choice between those two operations. In this paper, both processes are discussed using computational CFD simulation through ANSYS-Fluent software. Only 3D half section of the packed column was considered with one packed bed. The packed bed was characterized in our case as a porous media. The simulations were carried out at transient state conditions. A multi-component gas and liquid mixture were used out in the two processes. We utilized the Euler-Lagrange approach in which the gas was treated as a continuum phase and the liquid as a group of dispersed particles. The heat and the mass transfer process was modeled using multi-component droplet evaporation approach. The results show that the counter-current process performs better than the co-current, although such limitations of our approach are noted. This comparison gives accurate results for computations times higher than 2 s, at different gas velocity and at packed bed porosity of 0.9.

Keywords: co-current, counter-current, Euler-Lagrange model, heat transfer, mass transfer

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Authors: J. Belovickis, V. Samulionis, J. Banys, M. V. Silibin, A. V. Solnyshkin, A. V. Sysa

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Ferroelectric polymers exhibit good flexibility, processability and low cost of production. Doping of ferroelectric polymers with nanofillers may modify its dielectric, elastic or piezoelectric properties. Carbon nanotubes are one of the ingredients that can improve the mechanical properties of polymer based composites. In this work, we report on both the ultrasonic and the dielectric properties of the copolymer polyvinylidene fluoride/tetrafluoroethylene (P(VDF-TrFE)) of the composition 70/30 mol% with various concentrations of carbon nanotubes (CNT). Experimental study of ultrasonic wave attenuation and velocity in these composites has been performed over wide temperature range (100 K – 410 K) using an ultrasonic automatic pulse-echo tecnique. The temperature dependences of ultrasonic velocity and attenuation showed anomalies attributed to the glass transition and paraelectric-ferroelectric phase transition. Our investigations showed mechanical losses to be dependent on the volume fraction of the CNTs within the composites. The existence of broad hysteresis of the ultrasonic wave attenuation and velocity within the nanocomposites is presented between cooling and heating cycles. By the means of dielectric spectroscopy, it is shown that the dielectric properties may be tuned by varying the volume fraction of the CNT fillers.

Keywords: carbon nanotubes, polymer composites, PVDF-TrFE, ultrasonic spectroscopy

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Authors: Jennifer E. Lynette

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The purpose of this study is to develop a nation-wide assessment tool to gauge the quality and efficiency of response activities by emergency personnel to fires in Denmark. Current fire incident reports lack detailed information that can lead to breakthroughs in research and improve emergency response efforts. Information generated from the report database is analyzed and assessed for efficiency and quality. By utilizing information collection gaps in the incident reports, an improved, indepth, and streamlined quality gauging system is developed for use by fire brigades. This study pinpoints previously unrecorded factors involved in the response phases of a fire. Variables are recorded and ranked based on their influence to event outcome. By assessing and measuring these data points, quality standards are developed. These quality standards include details of the response phase previously overlooked which individually and cumulatively impact the overall success of a fire response effort. Through the application of this tool and implementation of associated quality standards at Denmark’s fire brigades, there is potential to increase efficiency and quality in the preparedness and response phases, thereby saving additional lives, property, and resources.

Keywords: emergency management, fire, preparedness, quality standards, response

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Authors: Z. Miao, Y. Chu, Y. Zhang

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The unique cholesteric phase liquid crystals obtained by mixing nematic liquid crystals with chiral dopants have gained valuable applications in the display field for their selective reflection and circular dichroism properties. The periodic arrangement of the helical structure of cholesteric liquid crystals makes it possible to produce Bragg reflection of circularly polarized light irradiated perpendicularly to the liquid crystals and, therefore, to acquire semi- or fully reflective surfaces or films. If the polymer-liquid crystal composites are combined with polymeric monomers, commercialized reflective broadband films can be fabricated. In this study, the polymer-liquid crystal composites reflecting visible light region (wavelength centered at 550 nm) were studied to analyze the effects of AC electric field at different voltages and frequencies on the optical texture of the composites, as well as the effects of polymerization temperature and ultraviolet (UV) intensity on the polymerization reaction and reflection bandwidth. The optimal sample was finally obtained at 100Hz, 120V, 30℃, 1.00 mW/cm², which provides a research suggestion to solve the influencing factors of visible light reflection bandwidths.

Keywords: cholesteric liquid crystal, reflection bandwidths, negative dielectric anisotropy, planar texture

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Authors: S. Nqayi

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Understanding the structural, electronic, and magnetic properties of nanomaterials is essential for developing next-generation electronic and spintronic devices, contributing to the progress of nanoscience and nanotechnology applications. Multiferroic materials, with intimately coupled ferroic-order parameters, are widely considered to breed fascinating physical properties and provide unique opportunities for the development of next-generation devices, like multistate non-volatile memory. In this study, we are set to investigate the structural, electronic, and magnetic properties of the frustrated Feᴵᴵ/Smⱽᴵ sublattice in relation to the widely studied perovskites for spintronics applications. The atomic composition, microstructure, crystallography, magnetization, thermal, and dielectric properties of a pyrochlore Sm₂Fe₂O₇ system synthesized using sol-gel methods are currently being investigated. Precursor powders were dissolved in citric acid monohydrate to obtain a solution. The obtained solution was stirred and heated using a magnetic stirrer to obtain the gel phase. Then, the gel was dried at 200°C to remove water and organic compounds and form an orange powder. The X-ray diffraction analysis confirms that the structure crystallized as a pyrochlore structure with a tetragonal F4mm (107) symmetry. The presence of Fe³⁺/Fe⁴⁺ mixed states is also revealed by XPS analysis.

Keywords: nanostructures, multiferroic materials, pyrochlores, spintronics

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Authors: Munoz A. Tatiana, Solano R. Brandon, Montes C. Juan, Cierco G. Javier

Abstract:

The hydrodynamic cavitation is a process in which the energy that the fluids have in the phase changes is used. From this energy, local temperatures greater than 5000 °C are obtained where thermal cracking of the fluid molecules takes place. The process applied to heavy oil affects variables such as viscosity, density, and composition, which constitutes an important improvement in the quality of crude oil. In this study, the need to design a software through mathematical integration models of mixing, cavitation, kinetics, and reactor, allows modeling changes in density, viscosity, and composition of a heavy oil crude, when the fluid passes through a hydrodynamic cavitation reactor. In order to evaluate the viability of this technique in the industry, a heavy oil of 18° API gravity, was simulated using naphtha as a hydrogen donor at concentrations of 1, 2 and 5% vol, where the simulation results showed an API gravity increase to 0.77, 1.21 and 1.93° respectively and a reduction viscosity by 9.9, 12.9 and 15.8%. The obtained results allow to have a favorable panorama on this technological development, an appropriate visualization on the generation of innovative knowledge of this technique and the technical-economic opportunity that benefits the development of the hydrocarbon sector related to heavy crude oil that includes the largest world oil production.

Keywords: hydrodynamic cavitation, thermal cracking, hydrogen donor, heavy oil upgrading, simulator

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Authors: Kuldeep Rawat, Michael O'Shea, Maureen McGough

Abstract:

The paper will discuss a National Institute of Justice (NIJ) funded project to provide cost-effective aviation technologies and research to support counter-poaching operations related to endangered, protected, and/or regulated wildlife. The goal of this project is to provide cost-effective aviation technology and research support to Kenya Wildlife Service (KWS) in their counter-poaching efforts. In pursuit of this goal, Elizabeth City State University (ECSU) is assisting the National Institute of Justice (NIJ) in enhancing the Kenya Wildlife Service’s aviation technology and related capacity to meet its counter-poaching mission. Poaching, at its core, is systemic as poachers go to the most extreme lengths to kill high target species such as elephant and rhino. These high target wildlife species live in underdeveloped or impoverished nations, where poachers find fewer barriers to their operations. In Kenya, with fifty-nine (59) parks and reserves, spread over an area of 225,830 square miles (584,897 square kilometers) adequate surveillance on the ground is next to impossible. Cost-effective aviation surveillance technologies, based on a comprehensive needs assessment and operational evaluation, are needed to curb poaching and effectively prevent wildlife trafficking. As one of the premier law enforcement Air Wings in East Africa, KWS plays a crucial role in Kenya, not only in counter-poaching and wildlife conservation efforts, but in aerial surveillance, counterterrorism and national security efforts as well. While the Air Wing has done, a remarkable job conducting aerial patrols with limited resources, additional aircraft and upgraded technology should significantly advance the Air Wing’s ability to achieve its wildlife protection mission. The project includes: (i) Needs Assessment of the KWS Air Wing, to include the identification of resources, current and prospective capacity, operational challenges and priority goals for expansion, (ii) Acquisition of Low-Cost Aviation Technology to meet priority needs, and (iii) Operational Evaluation of technology performance, with a focus on implementation and effectiveness. The Needs Assessment reflects the priorities identified through two site visits to the KWS Air Wing in Nairobi, Kenya, as well as field visits to multiple national parks receiving aerial support and interviewing/surveying KWS Air wing pilots and leadership. Needs Assessment identified some immediate technology needs that includes, GPS with upgrades, including weather application, Night flying capabilities, to include runway lights and night vision technology, Cameras and surveillance equipment, Flight tracking system and/or Emergency Position Indicating Radio Beacon, Lightweight ballistic-resistant body armor, and medical equipment, to include a customized stretcher and standard medical evacuation equipment. Results of this assessment, along with significant input from the KWS Air Wing, will guide the second phase of this project: technology acquisition. Acquired technology will then be evaluated in the field, with a focus on implementation and effectiveness. Results will ultimately be translated for any rural or tribal law enforcement agencies with comparable aerial surveillance missions and operational environments, and jurisdictional challenges, seeking to implement low-cost aviation technology. Results from Needs Assessment phase, including survey results and our ongoing technology acquisition and baseline operational evaluation will be discussed in the paper.

Keywords: aerial surveillance mission, aviation technology, counter-poaching, wildlife protection

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Authors: Giuseppe Timperio, Robert de Souza

Abstract:

Logistics operations in the context of disaster response are characterized by a high degree of complexity due to the combined effect of a large number of stakeholders involved, time pressure, uncertainties at various levels, massive deployment of goods and personnel, and gigantic financial flow to be managed. It also involves several autonomous parties such as government agencies, militaries, NGOs, UN agencies, private sector to name few, to have a highly collaborative approach especially in the critical phase of the immediate response. This is particularly true in the context of L3 emergencies that are the most severe, large-scale humanitarian crises. Decision-making processes in disaster management are thus extremely difficult due to the presence of multiple decision-makers involved, and the complexity of the tasks being tackled. Hence, in this paper, we look at applying ICT based solutions to enable a speedy and effective decision making in the golden window of humanitarian operations. A high-level view of ICT based solutions in the context of logistics operations for humanitarian response in Southeast Asia is presented, and their viability in a real-life case about logistics network design is explored.

Keywords: decision support, disaster preparedness, humanitarian logistics, network design

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Authors: Akhtar Naveed, Kanwal Shahla, Khan HMS, Rasool Fatima, Ijaz Shakeel

Abstract:

The focus of the study was to design, develop and characterize in vivo, a stable Emulgel formulation containing Anacardium occidentale L.(cashew extract) as an active ingredient. The formulation was prepared and kept at 8ºC, 25 ºC, 40ºC and 40ºC±RH for a period of 28 days. During this time period, stability, pH values, conductivity, organoleptic features (color, liquefaction, phase separation) were conducted at the intervals of day 1st, 2nd, 3rd , 7th, 14th and 28th days. In In vivo studies, the test formulation (5% Anacardium occidentale L, extract) and a base formulation (without cashew extract) were prepared and both were applied on cheek areas of healthy human female volunteers, after the skin sensitivity test of each volunteer, for a study period of 8 weeks after getting consent from them. Various parameters of skin like Melanin level, Erythema level, and skin elasticity were measured at regular time intervals. Results of the study were analyzed by statistical techniques i.e. Two Way ANOVA and paired sample t-test. The result showed significant results as the p ≤ 0.05. Findings of paired sample t-test explained that test formulation have profound effects on skin parameters when compared with control formulation.

Keywords: Anacardium occientale L., anti-oxidant, cashew nut, emulgel

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Authors: Reynaldo Esquivel, Pedro Hernandez, Aaron Martinez-Higareda, Sergio Tena-Cano, Enrique Alvarez-Ramos, Armando Lucero-Acuna

Abstract:

Stimuli-responsive nanomaterials play an essential role in loading, transporting and well-distribution of anti-cancer compounds in the cellular surroundings. The outstanding properties as the Lower Critical Solution Temperature (LCST), hydrolytic cleavage and protonation/deprotonation cycle, govern the release and delivery mechanisms of payloads. In this contribution, we experimentally determine the load efficiency and release of antineoplastic Vincristine Sulfate into PNIPAM-Interpenetrated-Chitosan (PIntC) nanoparticles. Structural analysis was performed by Fourier Transform Infrared Spectroscopy (FT-IR) and Proton Nuclear Magnetic Resonance (1HNMR). ζ-Potential (ζ) and Hydrodynamic diameter (DH) measurements were monitored by Electrophoretic Mobility (EM) and Dynamic Light scattering (DLS) respectively. Mathematical analysis of the release pharmacokinetics reveals a three-phase model above LCST, while a monophasic of Vincristine release model was observed at 32 °C. Cytotoxic essays reveal a noticeable enhancement of Vincristine effectiveness at low drug concentration on HeLa cervix cancer and MDA-MB-231 breast cancer.

Keywords: nanoparticles, vincristine, drug delivery, PNIPAM

Procedia PDF Downloads 156