Search results for: heavy metal stress

Authors: M. Dagim Yoseph, M. K. Savage, A. D. Jolly, C. J. Ebinger

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Whakaari/White Island has been the most active New Zealand volcano in the 21st century, producing small phreatic and phreatomagmatic eruptions, which are hard to predict. The most recent eruption occurred in 2019, tragically claiming the lives of 22 individuals and causing numerous injuries. We employed shear-wave splitting analyses to investigate variations in anisotropy between 2018 and 2020, during quiescence, unrest, and the eruption. We examined spatial and temporal variations in 3499 shear-wave splitting and 2656 V_p/V_s ratio measurements. Comparing shear-wave splitting parameters from similar earthquake paths across different times indicates that the observed temporal changes are unlikely to result from variations in earthquake paths through media with spatial variability. Instead, these changes may stem from variations in anisotropy over time, likely caused by changes in crack alignment due to stress or varying fluid content.

Keywords: background seismic waves, fast orientations, seismic anisotropy, V_p/V_s ratio

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Authors: Wided Zerguine, Farid Habelhames

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The performance of photovoltaic devices with a light absorber consisting of a single-type conjugated polymer is poor, due to a low photo-generation yield of charge carriers, strong radiative recombination’s and low mobility of charge carriers. Recently, it has been shown that ultra-fast photoinduced charge transfer can also occur between a conjugated polymer and a metal oxide semiconductor such as SnO2, TiO2, ZnO, Nb2O5, etc. This has led to the fabrication of photovoltaic devices based on composites of oxide semiconductor nanoparticles embedded in a conjugated polymer matrix. In this work, Poly [2-methoxy-5-(20-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV), (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) and titanium dioxide (TiO2) nanoparticles (n-type) were dissolved, mixed and deposited by physical methods (spin-coating) on indium tin-oxide (ITO) substrate. The incorporation of the titanium dioxide nanoparticles changed the morphology and increased the roughness of polymers film (MEH-PPV/PCBM), and the photocurrent density of the composite (MEH-PPV/PCBM +n-TiO2) was higher than that of single MEHPPV/ PCBM film. The study showed that the presence of n-TiO2 particles in the polymeric film improves the photoelectrochemical properties of MEH-PPV/PCBM composite.

Keywords: photocurrent density, organic nanostructures, hybrid coating, conducting polymer, titanium dioxide

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Authors: Hyunchul Oh

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One of the challenges in modern separation science and technology is the separation of hydrogen isotopes mixtures since D2 and H2 consist of almost identical size, shape and thermodynamic properties. Recently, quantum sieving of isotopes by confinement in narrow space has been proposed as an alternative technique. Despite many theoretical suggestions, however, it has been difficult to discover a feasible microporous material up to now. Among various porous materials, the novel class of microporous framework materials (COFs, ZIFs and MOFs) is considered as a promising material class for isotope sieving due to ultra-high porosity and uniform pore size which can be tailored. Hence, we investigate experimentally the fundamental correlation between D2/H2 molar ratio and pore size at optimized operating conditions by using different ultramicroporous frameworks. The D2/H2 molar ratio is strongly depending on pore size, pressure and temperature. An experimentally determined optimum pore diameter for quantum sieving lies between 3.0 and 3.4 Å which can be an important guideline for designing and developing feasible microporous frameworks for isotope separation. Afterwards, we report a novel strategy for efficient hydrogen isotope separation at technologically relevant operating pressure through the development of quantum sieving exploited by the pore aperture engineering. The strategy involves installation of flexible components in the pores of the framework to tune the pore surface.

Keywords: gas adsorption, hydrogen isotope, metal organic frameworks(MOFs), quantum sieving

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Authors: Mohammadreza Nezamirad, Sepideh Amirahmadian, Nasim Sabetpour, Azadeh Yazdi, Amirmasoud Hamedi

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Cavitation inside the diesel injector nozzle is investigated numerically in this study. Reynolds Stress Navier Stokes set of equations (RANS) are utilized to investigate flow behavior inside the nozzle numerically. Moreover, K-ε turbulent model is found to be a better approach comparing to K-ω turbulent model. Winklhofer rectangular shape nozzle is also simulated in order to verify the current numerical scheme, and with, mass flow rate approach, the current solution is verified. Afterward, a six-hole real-size nozzle was simulated, and it was found that among different fuels used in this study with the same condition, diesel fuel provides the largest length of cavitation. Also, it was found that at the same boundary condition, RME fuel leads to the highest value of discharge coefficient and mass flow rate.

Keywords: cavitation, diesel fuel, CFD, real size nozzle, discharge coefficient

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Authors: Noha Mohamed Abdelhafez Dahy, Azza Abd El-Aziz, Eman Ahmed, Marwa El-Sayed

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Osteoporosis is a metabolic bone disease characterized by low bone mass, deterioration of bone tissue, and disruption of bone microarchitecture, which leads to compromised bone strength and an increased risk of fracture, commonly it occurs in women 10-15 years after menopause, the mean age of menopause is 51 years. Menopause is natural physiological changes primary because of decline of ovaries function with age which leads to decrease of estrogen hormone production which is the main hormone for bone continuous remodeling for bone density maintenance. Exercise increase stimulation of bone growth to keep bone mass by the effect of the mechanical stimulation, antigravity loading and stress exerted on musculoskeletal muscles. Purpose: This study aimed to determine the effect of aerobic exercise on estrogen hormone and bone mineral density (BMD) in osteoporotic women and the correlation between the estrogen and BMD.

Keywords: Osteoporosis, Postmenopause, Aerobic exercise, DEXA, Serum Estrogen

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Authors: Gurinder Singh Brar, Sarbjeet Singh, Harry Garg

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Wire Electric Discharge Machining (WEDM) is thermal machining process capable of machining very hard electrically conductive material irrespective of their hardness. WEDM is being widely used to machine micro-scale parts with the high dimensional accuracy and surface finish. The objective of this paper is to optimize the process parameters of wire EDM to fabricate the microchannels and to calculate the surface finish and material removal rate of microchannels fabricated using wire EDM. The material used is aluminum 6061 alloy. The experiments were performed using CNC wire cut electric discharge machine. The effect of various parameters of WEDM like pulse on time (TON) with the levels (100, 150, 200), pulse off time (TOFF) with the levels (25, 35, 45) and current (IP) with the levels (105, 110, 115) were investigated to study the effect on output parameter i.e. Surface Roughness and Material Removal Rate (MRR). Each experiment was conducted under different conditions of a pulse on time, pulse off time and peak current. For material removal rate, TON and Ip were the most significant process parameter. MRR increases with the increase in TON and Ip and decreases with the increase in TOFF. For surface roughness, TON and Ip have the maximum effect and TOFF was found out to be less effective.

Keywords: microchannels, Wire Electric Discharge Machining (WEDM), Metal Removal Rate (MRR), surface finish

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Authors: Ratchada Sopakayang, Gerhard A. Holzapfel

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In this study, a new constitutive model is developed to describe the hyperelastic behavior of collagenous tissues with a parallel arrangement of collagen fibers such as ligaments and tendons. The model is formulated using a continuum approach incorporating the structural changes of the main tissue components: collagen fibers, proteoglycan-rich matrix and fiber-matrix interaction. The mechanical contribution of the interaction between the fibers and the matrix is simply expressed by a coupling term. The structural change of the collagen fibers is incorporated in the constitutive model to describe the activation of the fibers under tissue straining. Finally, the constitutive model can easily describe the stress-stretch nonlinearity which occurs when a ligament/tendon is axially stretched. This study shows that the interaction between the fibers and the matrix contributes to the mechanical tissue response. Therefore, the model may lead to a better understanding of the physiological mechanisms of ligaments and tendons under axial loading.

Keywords: constitutive model, fiber-matrix, hyperelasticity, interaction, ligament, tendon

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Authors: O. Starineca, I. Voronchuk

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Human Resources (HR) selection and training have various implementation possibilities depending on an organization’s abilities and peculiarities. We propose to base HR selection and training decisions about on a competence-based approach. HR selection and training of employees are topical as there is room for improvement in this field; therefore, the aim of the research is to propose rational decision-making approaches for an organization HR selection and training choice. Our proposals are based on the training development and competence-based selection approaches created within previous researches i.e. Analytic-Hierarchy Process (AHP) and Linear Programming. Literature review on non-formal education, competence-based selection, AHP form our theoretical background. Some educational service providers in Latvia offer employees training, e.g. motivation, computer skills, accounting, law, ethics, stress management, etc. that are topical for Public Administration. Competence-based approach is a rational base for rational decision-making in both HR selection and considering HR training.

Keywords: competence-based selection, human resource, training, decision-making

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Authors: Yi Jin, Xu Tang, Cuiyang Feng

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The ‘11th five-year’ and ‘12th five-year’ plans have clearly put forward to strictly control the total amount and intensity of energy and water consumption. The synergy effect of energy and water has rarely been considered in the process of energy and water saving in China, where its contribution cannot be maximized. Energy sectors consume large amounts of energy and water when producing massive energy, which makes them both energy and water intensive. Therefore, the synergy effect in these sectors is significant. This paper assesses and optimizes the synergy effect in three energy sectors under the background of promoting energy and water saving. Results show that: From the perspective of critical path, chemical industry, mining and processing of non-metal ores and smelting and pressing of metals are coupling points in the process of energy and water flowing to energy sectors, in which the implementation of energy and water saving policies can bring significant synergy effect. Multi-objective optimization shows that increasing efforts on input restructuring can effectively improve synergy effects; relatively large synergetic energy saving and little water saving are obtained after solely reducing the energy and water intensity of coupling sectors. By optimizing the input structure of sectors, especially the coupling sectors, the synergy effect of energy and water saving can be improved in energy sectors under the premise of keeping economy running stably.

Keywords: critical path, energy sector, multi-objective optimization, synergy effect, water

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Authors: Jeff A. Tysinger, Dawn P. Tysinger

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The aim of this paper is to theoretically apply Bowen’s understanding of triangulation and triads to school psychology intern supervision so that it can assist in the conceptualization of the dynamics of intern supervision and provide some key methods to address common issues. The school psychology internship is the capstone experience for the school psychologist in training. It involves three key participants whose relationships will determine the success of the internship.  To understand the potential effect, Bowen’s family systems theory can be applied to the supervision relationship. He describes a way to resolve stress between two people by triangulating or binging in a third person. He applies this to a nuclear family, but school psychology intern supervision requires the marriage of an intern, field supervisor, and university supervisor; thus, setting all up for possible triangulation. The consequences of triangulation can apply to standards and requirements, direct supervision, and intern evaluation. Strategies from family systems theory to decrease the negative impact of supervision triangulation.

Keywords: family systems theory, intern supervision, school psychology training, triangulation

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Authors: Sreeparna Majee, G. C. Shit

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Unsteady blood flow has been numerically investigated through stenosed arteries to achieve an idea about the physiological blood flow pattern in diseased arteries. The blood is treated as Newtonian fluid and the arterial wall is considered to be rigid having deposition of plaque in its lumen. For direct numerical simulation, vorticity-stream function formulation has been adopted to solve the problem using implicit finite difference method by developing well known Peaceman-Rachford Alternating Direction Implicit (ADI) scheme. The effects of magnetic parameter and Reynolds number on velocity and wall shear stress are being studied and presented quantitatively over the entire arterial segment. The streamlines have been plotted to understand the flow pattern in the stenosed artery, which has significant alterations in the downstream of the stenosis in the presence of magnetic field. The results show that there are nominal changes in the flow pattern when magnetic field strength is enhanced upto 8T which can have remarkable usage to MRI machines.

Keywords: magnetohydrodynamics, blood flow, stenosis, energy dissipation

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Authors: Maciej Major, Izabela Major

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The aim of this paper is a numerical analysis of three-layered block design to walls construction subjected to the dynamic load. The block consists of the layers: concrete with rubber pads in shape of crosses, space filled with air and concrete with I-shape rubber pads. The main purpose of rubber inserts embedded during the production process is additional protection against the transversal dynamic load. For the analysis, as rubber, the Zahorski hyperelastic incompressible material model was assumed. A concentrated force as dynamic load applied to the external block surface was investigated. The results for the considered block observed as the stress distribution plot were compared to the results obtained for the solid concrete block. In order to estimate the percentage damping of proposed composite, rubber-concrete block in relation to the solid block the numerical analysis with the use of finite element method based on ADINA software was performed.

Keywords: dynamics, composite, rubber, Zahorski

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Authors: Ali N. Suri, Ahmad A. Al-Makhlufi

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Sandwich construction is widely accepted as a method of construction especially in the aircraft industry. It is a type of stressed skin construction formed by bonding two thin faces to a thick core, the faces resist all of the applied edge loads and provide all or nearly all of the required rigidities, the core spaces the faces to increase cross section moment of inertia about common neutral axis and transmit shear between them provides a perfect bond between core and faces is made. Material for face sheets can be of metal or reinforced plastics laminates, core material can be metallic cores of thin sheets forming corrugation or honeycomb, or non-metallic core of Balsa wood, plastic foams, or honeycomb made of reinforced plastics. For in plane axial loading web core and web-foam core Sandwich panels can fail by local buckling of plates forming the cross section with buckling wave length of the order of length of spacing between webs. In this study local buckling of web core and web-foam core Sandwich panels is carried out for given materials of facing and core, and given panel overall dimension for different combinations of cross section geometries. The Finite Strip Method is used for the analysis, and Fortran based computer program is developed and used.

Keywords: local buckling, finite strip, sandwich panels, web and foam core

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Authors: S. Assylbekova, D. Zolotareva, A. Dauletbakov, Ye. Belyankova, S. Bayazit, A. Basharimova, A. Zazybin, A. Isimberlenova, A. Kakimova, M. Aydemir, A. Kairullinova

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Transfer hydrogenation (TH) is a key process in organic chemistry, especially in pharmaceutical and agrochemical synthesis, offering a safer and more sustainable approach compared to traditional methods. This work is devoted to the synthesis and use of ruthenium catalysts containing phosphinite ligands in TH reactions. Ruthenium complexes are particularly noteworthy for their effectiveness in asymmetric TH. Their stability and adaptability to different reaction environments make them ideal for both laboratory-scale and industrial applications. Phosphinite ligands (P(OR)R'2) are used in the synthesis of complexes to improve their properties. These ligands are known for their ability to finely tune the electronic and steric properties of metal centers. The electron-donating nature of the phosphorus atom, combined with the variability in the R and R' groups, allows for significant customization of the catalyst's properties. The purpose and difference of the work is to study the incorporation of a hydrophilic ionic liquid into the composition of a phosphinite ligand, which will then be converted into a catalyst. The technique involves the synthesis of a phosphinite ligand with an ionic liquid at room temperature under an inert atmosphere and then a ruthenium complex. Next, the TH reactions of acetophenone and its derivatives are carried out using the resulting catalyst. The conversion of ketone to alcohol is analyzed using a gas chromatograph. This study contributes to the understanding of the influence of catalyst physico-chemical properties on transfer hydrogenation results.

Keywords: transfer hydrogenation, ruthenium, catalysts, phosphinite ligands

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Authors: Sangmo Jon, Ganghyok Kim, Kwanghyok Jong, Ilnam Jo, Hyangsun Kim, Kukhyon Pae, GyeChol Sin

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The back contact dye solar cells (BCDSCs), in which the transparent conductive oxide (TCO) is omitted, have the potential to use intact low-cost general substrates such as glass, metal foil, and papers. Herein, we introduce a facile manufacturing method of a Ti back contact electrode for the BCDSCs. We found that the polylinkers such as poly(butyl titanate) have a strong binding property to make Ti particles connect with one another. A porous Ti film, which consists of Ti particles of ≤10㎛ size connected by a small amount of polylinkers, has an excellent low sheet resistance of 10 ohm sq⁻¹ for an efficient electron collection for DSCs. This Ti back contact electrode can be prepared by using a facile printing method under normal ambient conditions. Conjugating the new back contact electrode technology with the traditional monolithic structure using the carbon counter electrode, we fabricated all TCO-less DSCs. These four-layer structured DSCs consist of a dye-adsorbed nanocrystalline TiO₂ film on a glass substrate, a porous Ti back contact layer, a ZrO₂ spacer layer, and a carbon counter electrode in a layered structure. Under AM 1.5G and 100mWcm⁻² simulated sunlight illumination, the four-layer structured DSCs with N719 dyes and I⁻/I₃⁻ redox electrolytes achieved PCEs up to 5.21%.

Keywords: dye solar cells, TCO-less, back contact, printing, porous Ti film

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Authors: B. Prashantha, S. Anish

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The aim of the present study is to computationally evaluate the hemodynamic factors which affect the formation of atherosclerosis and plaque rupture in the human artery. An increase of atherosclerosis disease in the artery causes geometry changes, which results in hemodynamic changes such as flow separation, reattachment, and adhesion of new cells (chemotactic) in the artery. Hence, geometry plays an important role in the determining the nature of hemodynamic patterns. Influence of stenosis in the non-bifurcating artery, under pulsatile flow condition, has been studied on an idealized geometry. Analysis of flow through symmetric and asymmetric stenosis in the artery revealed the significance of oscillating shear index (OSI), flow separation, low WSS zones and secondary flow patterns on plaque formation. The observed characteristic of flow in the post-stenotic region highlight the importance of plaque eccentricity on the formation of secondary stenosis on the arterial wall.

Keywords: atherosclerotic plaque, oscillatory shear index, stenosis nature, wall shear stress

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Authors: Hamed Abshari, M. Reza Emami Azadi, Madjid Sadegh Azar

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For studying the overall instability of members of steel structures, there are several methods in which overall buckling and geometrical imperfection effects are considered in analysis. In first section, these methods are compared and ability of software to apply these methods is studied. Buckling loads determined from theoretical methods and software is compared for 2D one bay, one and two stories steel frames. To consider actual condition, buckling loads of three steel frames that have various dimensions are calculated and compared. Also, uncertainties that exist in loading and modeling of structures such as geometrical imperfection, yield stress, and modulus of elasticity in buckling load of 2D framed steel structures have been studied. By performing these uncertainties to each reliability analysis procedures (first-order, second-order, and simulation methods of reliability), one index of reliability from each procedure is determined. These values are studied and compared.

Keywords: buckling, second-order theory, reliability index, steel columns

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Authors: Juan Manuel Martinez Alvarez, Michele Chiumenti

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This work explores the benefit of the thermo-metallurgical simulation to tackle the Wire Laser Additive Manufacturing (WLAM) of low-carbon steel components. The Finite Element Analysis is calibrated by process monitoring via thermal imaging and thermocouples measurements, to study the complex thermo-metallurgical behavior inherent to the WLAM process of low carbon steel parts.A critical aspect is the analysis of the heterogeneity in the resulting microstructure. This heterogeneity depends on both the thermal history and the residual stresses experienced during the WLAM process. Because of low carbon grades are highly sensitive to quenching, a high-gradient microstructure often arises due to the layer-by-layer metal deposition in WLAM. The different phases have been identified by scanning electron microscope. A clear influence of the heterogeneities on the final mechanical performance has been established by the subsequent mechanical characterization. The thermo-metallurgical analysis has been used to determine the actual thermal history and the corresponding thermal gradients during the printing process. The correlation between the thermos-mechanical evolution, the printing parameters and scanning sequence has been established. Therefore, an enhanced printing strategy, including optimized process window has been used to minimize the microstructure heterogeneity at ArcelorMittal.

Keywords: additive manufacturing, numerical simulation, metallurgy, steel

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Authors: Herviyanti, Gusnidar, M. Harianti

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The objective of this research were: a) using low-rank coal (subbituminous) as main humate material sources because this material will not be anthracite, and cannot using to be an energy sources b) to examine residual effects of humic matter from subbituminous which was combined with P fertilizers to adsorp Al and Fe metal, improving soil fertility, and increasing P fertilizing efficiency and Oxisol productivity. Therefore, optimalization crop productivity of upland rice can be achieved. The experiment was designed using a 3 x 4 factorial with 3 replications in randomly groups design. The 1st factor was 3 ways incubating humate material with P-fertilizer, which are: I1 = Incubation of humate material 1 week, then incubation P-fertilizers 1 week; I2 = Incubation of humate materials and P fertilizers directly into the soil for 2 weeks; and I3 = humate material and P fertilizer mixed for 1 week, then incubation to the soil for 1 week. The 2nd factor was residual effects of humate material and P-fertilizer combination which are 4 doses H1 = 400 ppm (0.8 Mg/ha) + 100% R; H2 = 400 ppm + 75% R; H3 = 800 ppm (1.6 Mg/ha) + 100% R,; and H4 = 800 ppm + 75% R. The 2nd year research results showed that the best treatment was founded residue effect of 800 ppm humate material and 100% R P-fertilizer doses in I3 way incubation that is equal to 6.19 t ha-1 upland rice yield. However, this result is almost the same as residual effects of 800 ppm humate material + 75% R P-fertilizer doses and upland rice yield the 1st year. It was concluded that addition of humate material can given the efficiency of P-fertilizer using up to 25% until the 2nd season planted.

Keywords: humate materials, P-fertilizer, subbituminous, upland rice

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Authors: Boyu Li

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Mixed matrix membranes (MMMs), as a separation technology, can improve CO₂ recycling efficiency and reduce the environmental impacts associated with huge emissions. Nevertheless, many challenges must be overcome to design excellent selectivity and permeability performance MMMs. Herein, this work demonstrates the design of nano-scale GNPs (Cu-BDC@PEG) with strong compatibility and high free friction volume (FFV) is an effective way to construct non-interfacial voids MMMs with a desirable combination of selectivity and permeability. Notably, the FFV boosted thanks to the chain length and shape of the GNPs. With this, the permeability and selectivity of Cu-BDC@PEG/PVDF MMMs had also been significantly improved. As such, compatible Cu-BDC@PEG proves very efficient for resolving challenges of MMMs with poor compatibility on the basis of the interfacial defect. Poly (Ethylene Glycol) (PEG) with oxygen groups can be finely coordinated with Cu-MOFs to disperse Cu-BDC@PEG homogenously and form hydrogen bonds with matrix to achieve continuous phase. The resultant MMMs exhibited a simultaneous enhancement of gas permeability (853.1 Barrer) and ideal CO₂/N selectivity (41.7), which has surpassed Robenson's upper bound. Moreover, Cu-BDC@PEG/PVDF has a high-temperature resistance and a long time sustainably. This attractive separation performance of Cu-BDC@PEG/PVDF offered an exciting platform for the development of composite membranes for sustainable CO₂ separations.

Keywords: metal organic framework, CO₂ separation, mixed matrix membrane, polymer

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Authors: M. Bidi, H. Akhbari, S. Eslami, A. Bakhtiari

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Due to the high potential of solar energy utilization in Iran, development of related technologies is of great necessity. Linear parabolic collectors are among the most common and most efficient means to harness the solar energy. The main goal of this paper is design and construction of a parabolic trough collector to produce hot water and steam in Tehran. To provide precise and practical plans, 3D models of the collector under consideration were developed using Solidworks software. This collector was designed in a way that the tilt angle can be adjusted manually. To increase concentraion ratio, a small diameter absorber tube is selected and to enhance solar absorbtion, a shape of U-tube is used. One of the outstanding properties of this collector is its simple design and use of low cost metal and plastic materials in its manufacturing procedure. The collector under consideration was installed in Shahid Beheshti University of Tehran and the values of solar irradiation, ambient temperature, wind speed and collector steam production rate were measured in different days and hours of July. Results revealed that a 1×2 m parabolic trough collector located in Tehran is able to produce steam by the rate of 300ml/s under the condition of atmospheric pressure and without using a vacuum cover over the absorber tube.

Keywords: desalination, parabolic trough collector, direct steam production, solar water heater, design and construction

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Authors: Simon Bard, Martin Demleitner, Florian Schonl, Volker Altstadt

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For an electrically driven aircraft, whose engine is based on semiconductors, alternative materials are needed. The avoid hotspots in the materials thermally conductive polymers are necessary. Nevertheless, the mechanical properties of these materials should remain. Herein, the work of three years in a project with airbus and Siemens is presented. Different strategies have been pursued to achieve conductive fiber-reinforced composites: Metal-coated carbon fibers, pitch-based fibers and particle-loaded matrices have been investigated. In addition, a combination of copper-coated fibers and a conductive matrix has been successfully tested for its conductivity and mechanical properties. First, prepregs have been produced with a laboratory scale prepreg line, which can handle materials with maximum width of 300 mm. These materials have then been processed to fiber-reinforced laminates. For the PAN-fiber reinforced laminates, it could be shown that there is a strong dependency between fiber volume content and thermal conductivity. Laminates with 50 vol% of carbon fiber offer a conductivity of 0.6 W/mK, those with 66 vol% of fiber a thermal conductivity of 1 W/mK. With pitch-based fiber, the conductivity enhances to 1.5 W/mK for 61 vol% of fiber, compared to 0.81 W/mK with the same amount of fibers produced from PAN (+83% in conducitivity). The thermal conductivity of PAN-based composites with 50 vol% of fiber is at 0.6 W/mK, their nickel-coated counterparts with the same fiber volume content offer a conductivity of 1 W/mK, an increase of 66%.

Keywords: carbon, electric aircraft, polymer, thermal conductivity

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Authors: Meruyert Burumbayeva, Aiman Mussina, Gulnoza Aldabekova, Aiymtory Abildaeva, Gulshat Yerdenova, Aigul Kairgeldina

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this article introduces results of a research which purpose is evaluation the quality of life, the psychophysiological status, expressiveness of uneasiness at women teachers of the senior age group. At a research of quality of life of teachers the lowest values have been received from the indicators of the general state of health, vital activity, role emotional functioning and mental health. Every second woman-teacher noted high personal uneasiness; every third woman-teacher noted moderate situational uneasiness, confirming the existence of a professional stress. Revealed the interrelation between alarming conditions and a decrease in a mental component of health. Moreover, there was revealed exhaustion signs at low activity values that indicate a high tension of labor process.

Keywords: expressiveness of uneasiness, quality of life, psychophysiological status, component of health

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Authors: Yulia V. Krasavtseva, Tatiana V. Kornilova

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Risk-taking behaviors are not only dictated by cognitive components but also involve emotional aspects. Anticipatory emotions, involving both cognitive and affective mechanisms, are involved in decision-making in general, and risk-taking in particular. Affective reactions are prompted when an expectation or prediction is either validated or invalidated in the achieved result. This study aimed to combine predictions, anticipatory emotions, affective reactions, and personality traits in the context of risk-taking behaviors. An experimental online method Emotion and Prediction In a Casino (EPIC) was used, based on a casino-like roulette game. In a series of choices, the participant is presented with progressively riskier roulette combinations, where the potential sums of wins and losses increase with each choice and the participant is given a choice: to 'walk away' with the current sum of money or to 'play' the displayed roulette, thus accepting the implicit risk. Before and after the result is displayed, participants also rate their emotions, using the Self-Assessment Mannequin [Bradley, Lang, 1994], picking a picture, representing the intensity of pleasure, arousal, and dominance. The following personality measures were used: 1) Personal Decision-Making Factors [Kornilova, 2003] assessing risk and rationality; 2) I7 – Impulsivity Questionnaire [Kornilova, 1995] assessing impulsiveness, risk readiness, and empathy and 3) Subjective Risk Intelligence Scale [Craparo et al., 2018] assessing negative attitude toward uncertainty, emotional stress vulnerability, imaginative capability, and problem-solving self-efficacy. Two groups of participants took part in the study: 1) 98 university students (Mage=19.71, SD=3.25; 72% female) and 2) 94 online participants (Mage=28.25, SD=8.25; 89% female). Online participants were recruited via social media. Students with high rationality rated their pleasure and dominance before and after choices as lower (ρ from -2.6 to -2.7, p < 0.05). Those with high levels of impulsivity rated their arousal lower before finding out their result (ρ from 2.5 - 3.7, p < 0.05), while also rating their dominance as low (ρ from -3 to -3.7, p < 0.05). Students prone to risk-rated their pleasure and arousal before and after higher (ρ from 2.5 - 3.6, p < 0.05). High empathy was positively correlated with arousal after learning the result. High emotional stress vulnerability positively correlates with arousal and pleasure after the choice (ρ from 3.9 - 5.7, p < 0.05). Negative attitude to uncertainty is correlated with high anticipatory and reactive arousal (ρ from 2.7 - 5.7, p < 0.05). High imaginative capability correlates negatively with anticipatory and reactive dominance (ρ from - 3.4 to - 4.3, p < 0.05). Pleasure (.492), arousal (.590), and dominance (.551) before and after the result were positively correlated. Higher predictions positively correlated with reactive pleasure and arousal. In a riskier scenario (6/8 chances to win), anticipatory arousal was negatively correlated with the pleasure emotion (-.326) and vice versa (-.265). Correlations occur regardless of the roulette outcome. In conclusion, risk-taking behaviors are linked not only to personality traits but also to anticipatory emotions and affect in a modeled casino setting. Acknowledgment: The study was supported by the Russian Foundation for Basic Research, project 19-29-07069.

Keywords: anticipatory emotions, casino game, risk taking, impulsiveness

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Authors: Paul Onyegbule, Harjit Singh

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Vacuum glazing is an innovative transparent thermal insulator that has application in high performance window, especially in renewable energy. Different materials as well as sealing methods have been adopted to seal windows with different temperatures. The impact of temperatures on sealing layers has been found to have significant effects on the microstructure of the seal. This paper seeks to investigate the effects of sealing materials specifically glass powder and flux compound (borax) for vacuum glazing. The findings of the experiment conducted show that the sealing material was rigid with some leakage around the edge, and we found that this could be stopped by enhancing the uniformity of the seal within the periphery. Also, we found that due to the intense tensile stress from the oven surface temperature of the seal at 200 ⁰C, a crack was observed at the side of the glass. Based on the above findings, this study concludes that a glass powder with a lower melting temperature of below 250 ⁰C with the addition of an adhesive (borax flux) should be used for future vacuum seals.

Keywords: double glazed windows, U-value, heat loss, borax powder, edge seal

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Authors: H. Al-Baghli

Abstract:

Laboratory trial results of mixing crumb rubber produced from discarded tires with 60/70 pen grade Kuwaiti bitumen are presented on this paper. PG grading and multiple stress creep recovery tests were conducted on Kuwaiti bitumen blended with 15% and 18% crumb rubber at temperatures ranging from 40 to 70 °C. The results from elastic recovery and non-recoverable creep presented optimum performance at 18% rubber content. The optimum rubberized-bitumen mix was next transformed into a pelletized form (PelletPave^®), and was used as a partial replacement to the conventional bitumen in the manufacture of continuously graded hot mix asphalts at a number of binder contents. The trialed PelletPave^® contents were at 2.5%, 3.0%, and 3.5% by mass of asphalt mix. In this investigation, it was not possible to utilize the results of standard Marshall method of mix design (i.e. volumetric, stability and flow tests) and subsequently additional assessment of mix compactability was carried out using gyratory compactor in order to determine the optimum PelletPave^® and total binder contents.

Keywords: crumb rubber, Marshall mix design, PG grading, rubberized-bitumen

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Authors: Amaba, Marinela C., Espino, Gianne Ericka S. J. Valencia, Zeia Beatriz C.

Abstract:

This study aims to determine the moderating role of attachment style on the relationship between psychological symptoms and well-being of mental health practitioners in rehabilitation centers that are accredited of the Department of Health in Pampanga. Using the data gathered from 46 mental health practitioners, multiple regression models were conducted to test the main and moderating effects of attachment styles. The findings show that all three psychological symptoms namely depression, anxiety, and stress have main effects on their general well-being on a negative direction. However, attachment style did not moderate the relationship between the psychological symptoms and general well-being. On one hand, results about the relationship of psychological symptoms and well-being are consistent to previous findings of other studies while on the other hand, results in moderation were contradicting.

Keywords: attachment style, psychological symptoms, well-being, mental health practitioners, rehabilitation centers

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Authors: Camille A. Issa, Omar Masri

Abstract:

In the study, the commercial finite element software Abaqus was used to develop a three-dimensional nonlinear finite element model capable of simulating the pull-out test of reinforcing bars from underwater concrete. The results of thirty-two pull-out tests that have different parameters were implemented in the software to study the effect of the concrete cover, the bar size, the use of stirrups, and the compressive strength of concrete. The interaction properties used in the model provided accurate results in comparison with the experimental bond-slip results, thus the model has successfully simulated the pull-out test. The results of the finite element model are used to better understand and visualize the distribution of stresses in each component of the model, and to study the effect of the various parameters used in this study including the role of the stirrups in preventing the stress from reaching to the sides of the specimens.

Keywords: pull-out test, bond strength, underwater concrete, nonlinear finite element analysis, abaqus

Procedia PDF Downloads 445

Authors: K. Kamburova, N. Boshkova, N. Boshkov, T. Radeva

Abstract:

Coatings based on polyaniline (PANI) can improve the resistance of steel against corrosion. Two forms of PANI are generally accepted to have effective protection of steel: the conducting emeraldine salt (ES) and the non-conducting emeraldine base (EB). The ability to intercept electrons at the metal surface and to transport them is typically attributed to ES, while the success of EB as an anticorrosive additive in the coating is attributed to its ability to oxidize and reduce in a reversible way. This electrochemical mechanism is probably combined with barrier effect against corrosion species. In this work, we describe the preparation of stable suspensions of colloidal PANI-SiO₂ particles, suitable for obtaining of composite anticorrosive coating on steel. Electrokinetic data as a function of pH are presented, showing that the zeta potentials of the PANI-SiO₂ particles are governed primarily by the charged groups at the silica oxide surface. Electrosteric stabilization of the PANI-SiO₂ particles’ suspension against aggregation is realized at pH > 5.5 (EB form of PANI) by adsorption of positively charged polyelectrolyte molecules onto negatively charged PANI-SiO₂ particles. We anticipate that incorporation of the small particles will provide a more homogeneous distribution in the coating matrix and will decrease the negative effect on barrier properties of the composite coating.

Keywords: particles, stable dispersion, composite coatings, corrosion protection

Procedia PDF Downloads 179

Authors: Alma Khasenovna Zhakina, Arnt Oxana Vasilievna, Vasilets Evgeny Petrovich

Abstract:

The aim of this project is to develop methods for obtaining new molecularly imprinted polymers from coal waste to study their structure, structural and morphological features and properties. Recently, the development of molecularly imprinted polymers has become one of the hot topics for researchers. Modern research indicates the broad prospects of rapidly developing molecular imprinting technologies for creating a new generation of sorption materials. The attractiveness of this area of research lies in the fact that the use of imprinted polymers is not limited to scientific research; they are already being introduced in the chemical, pharmaceutical and biotechnological industries, primarily at the stages of purification of the final product. For the use of molecularly imprinted polymers in the development of sorption material, their ability to selectively remove pollutants, including trace concentrations, is of fundamental importance, and the exceptional stability of polymeric materials under harsh conditions makes it possible to simplify the process of water purification as a whole. The scientific and technical effect is associated with the development of technologies for the production of new molecularly imprinted polymers, the establishment of optimal conditions for their production and the creation of effective imprinted sorbents on their basis for wastewater treatment from heavy metals. The social effect is due to the fact that the use of coal waste as a feedstock for the production of imprinted sorbents will make it possible in the future to create new industries with additional jobs and obtain competitive multi-purpose products. The economic and multiplier effect is associated with the low cost of the final product due to the involvement of local coal waste in the production, reduction of transport, customs and other costs.

Keywords: imprinted polymers, coal waste, polymerization, template, customized sorbents

Procedia PDF Downloads 71