Search results for: metal recovery

Authors: Daniel Y. Abebe, Jaehyouk Choi

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The idea of adding metallic energy dissipaters to a structure to absorb a large part of the seismic energy began four decades ago. There are several types of metal-based devices conceived as dampers for the seismic energy absorber whereby damages to the major structural components could be minimized for both new and existing structures. This paper aimed to develop and evaluate structural performance of both stiffened and non stiffened circular shear panel damper for passive seismic energy protection by inelastic deformation. Structural evaluation was done using commercially available nonlinear FE simulation program. Diameter-to-thickness ratio is employed as main parameter to investigate the hysteresis performance of stiffened and unstiffened circular shear panel. Depending on these parameters three different buckling mode and hysteretic behavior was found: yielding prior to buckling without strength degradation, yielding prior to buckling with strength degradation and yielding with buckling and strength degradation which forms pinching at initial displacement. Hence, the hysteresis behavior is identified, specimens which deform without strength degradation so it will be used as passive energy dissipating device in civil engineering structures.

Keywords: circular shear panel damper, FE analysis, hysteretic behavior, large deformation

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Authors: Manal Alosaimi

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Many rehabilitation strategies exist to aid persons with neurological disorders relearn motor skills through intensive training. Evidence supporting the theory that cortical areas involved in motor execution can be triggered by observing actions performed by others is attributed to the function of the mirror neuron system (MNS) indicates that activation of the MNS is associated with improvements in physical action and motor learning. Therefore, it is important to investigate the relationship between motor training (in this case, playing the drums) and the activation of the MNS. To achieve this, 15 healthy right-handed participants received drum-kit training for 21 weeks, during which time blood oxygen level-dependent (BOLD) signals were monitored in the brain using functional magnetic resonance imaging (fMRI). Participants were required to perform action–observation and action–execution fMRI tasks. The main results are that BOLD signals in classical regions of the MNS such as supramarginal gyri, inferior parietal lobule, and supplementary motor area increase significantly over the training period. Activation of these areas indicates that passive-observation of others performing these same skills may facilitate recovery of persons suffering from neurological disorders, and complement conventional rehabilitation programs that focus on action execution or intense training.

Keywords: fMRI, mirror neuron system, magnetic resonance imaging, neuroplasticity, drumming, learning, music, action observation, action execution

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Authors: Ashok Kumar, Sarita Sahu, H. N. Bar

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Low cycle fatigue behavior of a ferritic, martensitic pressure vessel steel at dynamic strain ageing regime of 250°C to 280°C has been investigated. Dynamic strain ageing is a mechanism that has attracted interests of researchers due to its fascinating inexplicable repetitive nature for quite a long time. The interaction of dynamic strain ageing and cyclic plasticity has been studied from the mechanistic point of view. Dynamic strain ageing gives rise to identical serrated flow behavior in tensile and compressive halves of hysteresis loops and this has been found to gives rise to initial cyclic hardening followed by softening behavior, where as in non-DSA regime continuous cyclic softening has been found to be the dominant mechanism. An appreciable sensitivity towards nature of serrations has been observed due to degree of hardening of stable loop. The increase in degree of hardening with strain amplitude in the regime where only A type serrations are present and it decreases with strain amplitude where A+B type of serrations are present. Masing type of locus has been found in the behavior of metal at 280°C. Cyclic Stress Strain curve and Master curve has been constructed to decipher among the fatigue strength and ductility coefficients. Fractographic examinations have also shown a competition between progression of striations and secondary cracking.

Keywords: dynamic strain ageing, hardening, low cycle fatigue, softening

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Authors: Ahmad Aroziki Abdul Aziz, Sakinah Mohd Alauddin, Ruzitah Mohd Salleh, Mohammed Iqbal Shueb

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This paper illustrates the effect of nano Magnesium Hydroxide (MH) loading on the thermal properties of Low Density Polyethylene (LDPE)/ Poly (ethylene-co vinyl acetate)(EVA) nano composite. Thermal studies were conducted, as it understanding is vital for preliminary development of new polymeric systems. Thermal analysis of nano composite was conducted using thermo gravimetric analysis (TGA), and differential scanning calorimetry (DSC). Major finding of TGA indicated two main stages of degradation process found at (350 ± 25 oC) and (480 ± 25 oC) respectively. Nano metal filler expressed better fire resistance as it stand over high degree of temperature. Furthermore, DSC analysis provided a stable glass temperature around 51 (±1 oC) and captured double melting point at 84 (±2 oC) and 108 (±2 oC). This binary melting point reflects the modification of nano filler to the polymer matrix forming melting crystals of folded and extended chain. The percent crystallinity of the samples grew vividly with increasing filler content. Overall, increasing the filler loading improved the degradation temperature and weight loss evidently and a better process and phase stability was captured in DSC.

Keywords: thermal properties, nano MH, nano particles, cable and wire, LDPE/EVA

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Authors: Andrey V. Samokhin, Nikolay V. Alekseev, Mikhail A. Sinaiskii

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The report presents the results of R&D of plasma-chemical production of W, W-Cu, W-Ni-Fe nanopowders as well as spherical micropowders of these compounds for their use in modern 3D printing technologies. Plasma-chemical synthesis of nanopowdersis based on the reduction of tungsten oxide compounds powders in a stream of hydrogen-containing low-temperature thermal plasma generated in an electric arc plasma torch. The synthesis of W-Cu and W-Ni-Fe nanocompositesiscarried out using the reduction of a mixture of the metal oxides. Using the synthesized tungsten-based nanocomposites powders, spherical composite micropowders with a submicron structure canbe manufactured by spray dryinggranulation of nanopowder suspension and subsequent densification and spheroidization of granules by melting in a low-temperature thermal plasma flow. The DC arc plasma systems are usedfor the synthesis of nanopowdersas well as for the spheroidization of microgranuls. Plasma systems have a capacity of up to 1 kg/h for nanopowder and up to 5 kg/h for spheroidized powder. All synthesized nanopowders consist of aggregated particles with sizes less than 100 nm, and nanoparticles of W-Cu and W-Ni-Fe composites have core (W) –shell (Cu or Ni-Fe) structures. The resulting dense spherical microparticles with a size of 20-60 microns have a submicron structure with a uniform distribution of metals over the particle volume. The produced tungsten-based nano- and spherical micropowderscan be used to develop new materials and manufacture products using advanced modern technologies.

Keywords: plasma, powders, production, tungsten-based

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Authors: Ahokas Mikko, Taskila Sanna, Varrio Kalle, Tanskanen Juha

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The present research aimed at the development of an energy efficient process for the concentration of starchy waste waters. The selected principle is mechanical vapor recompression evaporation (MVR) which leads to concentrated solid material and evaporated water phase. Evaporation removes water until a certain viscosity limit is reached. Materials with high viscosity cannot be concentrated using standard evaporators due to limitations of pumps and other constraints, such as wetting. Control of viscosity is thus essential for efficient evaporation. This applies especially to fluids in which due starch or other compounds the viscosity tends to increase via removal of water. In the present research, the effect of enzymes on evaporation of highly viscous starch industry waste waters was investigated. Wastewater samples were received from starch industry at pH of 4.8. Response surface methodology (RSM) was applied for the investigation of factor effects on the behaviour of concentrate during evaporation. The RSM was prepared using quadratic face-centered central composite design (CCF). The evaporation performance was evaluated by monitoring the viscosity of fluid during processing. Based on viscosity curves, the addition of glucoamylase reduced the viscosity during evaporation. This assumption was confirmed by CCF, suggesting that the use of starch decomposing glucoamylase allowed evaporation of the starchy wastewater to a relatively high total solid concentration without a detrimental increase in the viscosity. The results suggest that use of enzymes for reduction of viscosity during the evaporation allows more effective concentration of the wastewater and thereby recovery of potable water.

Keywords: viscous, wastewater, treatment, evaporation, concentration

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Authors: Jeffrey Cacho, Sherwin Reyes

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The research targeted enhancing energy utilization and reducing waste in roasting processes, particularly in Camarines Norte, where Bounty Agro Ventures Incorporated dominates through brands such as Chooks-to-Go, Uling Roaster, and Reyal. Competitors like Andok’s and Baliwag Lechon Manok also share the market. A staggering 90% of these businesses use traditional glass-type roasting furnaces fueled by wood charcoal, leading to significant energy loss and inefficiency due to suboptimal heat conservation. Only a mere 10% employ electric ovens. Many available furnaces, typically constructed from industrial materials through welding and other metal joining techniques, are not energy-efficient. Cost-prohibitive commercial options compel some micro-enterprises to fabricate their furnaces. The study proposed developing an eco-friendly, cost-effective roasting furnace with excellent heat retention. The distinct design aimed to reduce cooks' heat exposure and overall fuel consumption. The furnace features an angle bar frame, a combustion chute for fuel burning, a heat-retaining clay-walled chamber, and a top cover, all contributing to improved energy savings and user safety.

Keywords: biomass roasting furnace, heat storage, combustion chute, start-up roasting business

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Authors: Chung-Hung Tsai, Ya-Ping Li

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Tourism industry is highly depended on the natural environment and climate. Compared to other industries, it is more susceptible to environment and climate. Taiwan belongs to a sea island country and located in the subtropical monsoon zone. The events of climate variability, frequency of typhoons and rainfalls raged are caused regularly serious disaster. In traditional disaster assessment, it usually focuses on the disaster damage and risk assessment, which is short of the features from different industries to understand the impact of the restoring force in post-disaster resilience and the main factors that constitute resilience. The object of this study is based on disaster recovery experience of tourism area and to understand the main factors affecting the tourist area of disaster resilience. The combinations of literature review and interviews with experts are prepared an early indicator system of the disaster resilience. Then, it is screened through a Fuzzy Delphi Method and Analytic Network Process for weight analysis. Finally, this study will establish the tourism disaster resilience evaluation index system considering the Taiwan's tourism industry characteristics. We hope that be able to enhance disaster resilience after tourist areas and increases the sustainability of industrial development. It is expected to provide government departments the tourism industry as the future owner of the assets in extreme climates responses.

Keywords: resilience, Fuzzy Delphi Method, Analytic Network Process, industrial development

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Authors: Hossein Arfaeinia, Ahmad Jonidi Jafari, Sina Dobaradaran, Sadegh Niazi, Mojtaba Ehsanifar, Amir Zahedi

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Street dust and surface soil samples were collected from very heavy, heavy, medium and low traffic areas and natural site in Tehran, Iran. These samples were analyzed for some physical–chemical features, total and chemical speciation of selected metals and metalloids (Zn, Al, Sr, Pb, Cu, Cr, Cd, Co, Ni, and V) to study the effect of traffic on their mobility and accumulation in the environment. The pH, electrical conductivity (EC), carbonates and organic carbon (OC) values were similar in soil and dust samples from similar traffic areas. The traffic increases EC contents in dust/soil matrixes but has no effect on concentrations of metals and metalloids in soil samples. Rises in metal and metalloids levels with traffic were found in dust samples. Moreover, the traffic increases the percentage of acid soluble fraction and Fe and Mn oxides associated fractions of Pb and Zn. The mobilization of Cu, Zn, Pb, Cr in dust samples was easier than in soil. The speciation of metals and metalloids except Cd is mainly affected by physicochemical features in soil, although total metals and metalloids affected the speciation in dust samples (except chromium and nickel).

Keywords: street dust, surface soil, traffic, metals, metalloids, chemical speciation

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Authors: Pietro D'Ambrosio, Roberta D'Ambrosio

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The upgrading of the architectural and urban heritage of the urban historic centers almost always involves the planning for the reuse and refunctionalization of the structures. Such interventions have complexities linked to the need to take into account the urban and social context in which the structure and its intrinsic characteristics such as historical and artistic value are inserted. To these, of course, we have to add the need to make a preliminary estimate of recovery costs and more generally to assess the economic and financial sustainability of the whole project of re-socialization. Particular difficulties are encountered during the pre-assessment of costs since it is often impossible to perform analytical surveys and structural tests for both structural conditions and obvious cost and time constraints. The methodology proposed in this work, based on a multidisciplinary and data-driven approach, is aimed at obtaining, at very low cost, reasonably priced economic evaluations of the interventions to be carried out. In addition, the specific features of the approach used, derived from the predictive analysis techniques typically applied in complex IT domains (big data analytics), allow to obtain as a result indirectly the evaluation process of a shared database that can be used on a generalized basis to estimate such other projects. This makes the methodology particularly indicated in those cases where it is expected to intervene massively across entire areas of historical city centers. The methodology has been partially tested during a study aimed at assessing the feasibility of a project for the reuse of the monumental complex of San Massimo, located in the historic center of Salerno, and is being further investigated.

Keywords: evaluation, methodology, restoration, reuse

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Authors: Dessalegn Abera Waktole, Boru Jia, Zhengxing Zuo, Wei Wang, Nianling Kuang

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A flexible thermoelectric generator is one method for recycling waste heat. This research provides the optimum performance of a flexible thermoelectric generator with optimal geometric parameters and a detailed structural design. In this research, a numerical simulation and experiment were carried out to develop an efficient, flexible thermoelectric generator for energy harvesting from human skin. Heteromorphic electrodes and a polyimide substrate with a copper-printed circuit board were introduced into the structural design of a flexible thermoelectric generator. The heteromorphic electrode was used as a heat sink and component of a flexible thermoelectric generator to enhance the temperature difference within the thermoelectric legs. Both N-type and P-type thermoelectric legs were made of bismuth selenium telluride (Bi1.7Te3.7Se0.3) and bismuth antimony telluride (Bi0.4Sb1.6Te3). The output power of the flexible thermoelectric generator was analyzed under different heat source temperatures and heat dissipation conditions. The COMSOL Multiphysics 5.6 software was used to conduct the simulation, which was validated by experiment. It is recorded that the maximum power output of 232.064μW was obtained by considering different wind speed conditions, the ambient temperature of 20℃, and the heat source temperature of 36℃ under various load resistance conditions, which range from 0.24Ω to 0. 91Ω. According to this finding, heteromorphic electrodes have a significant impact on the performance of the device.

Keywords: flexible thermoelectric generator, optimization, performance, temperature gradient, waste heat recovery

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Authors: Anne Elain, Magali Le Fellic

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Halogenated Aromatic Compounds (HAC) are major organic pollutants that are detected in several environmental compartments as a result of their widespread use as solvents, pesticides and other industrial chemicals. The degradation of HAC simultaneously at low temperature and under saline conditions would be useful for remediation of polluted sites. Hence, microbial processes based on the metabolic activities of anaerobic bacteria are especially attractive from an economic and environmental point of view. Metabolites are generally less toxic, less likely to bioaccumulate and more susceptible for further degradation. Studies on biological reductive dehalogenation have largely been restricted to chlorinated compounds while relatively few have focussed on other HAC i.e., fluorinated, brominated or iodinated compounds. The objectives of the present work were to investigate the biodegradation of a mixture of triiodoaromatic molecules in industrial wastewater by an enriched bacterial consortium. Biodegradation of the mixture was studied during batch experiments in an anaerobic reactor. The degree of mineralization and recovery of halogen were monitored by HPLC-UV, TOC analysis and potentiometric titration. Providing ethanol as an electron donor was found to stimulate anaerobic reductive dehalogenation of HAC with a deiodination rate up to 12.4 mg.L-1 per day. Sodium chloride even at high concentration (10 mM) was found to have no influence on the degradation rates nor on the microbial viability. An analysis of the 16S rDNA (MicroSeq®) revealed that at least 6 bacteria were predominant in the enrichment, including Pseudomonas aeruginosa, Pseudomonas monteilii, Kocuria rhizophila, Ochrobacterium anthropi, Ralstonia pickettii and Rhizobium rhizogenes.

Keywords: halogenated aromatics, anaerobic biodegradation, deiodination, bacterial consortium

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Authors: Meshal Al-Samhan, Abdullah Al-Marshed

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Recently, there has been a tremendous increase in interest in nanotechnology applications and nanomaterials in the oilfield. In the last decade, the global increase in oil production resulted in large amounts of produced water, causing a significant problem for all producing countries and companies. This produced water deserves special attention and a study of its characteristics to understand and determine how it can be treated and later used for suitable applications such as water injection for Enhance Oil Recovery (EOR) without harming the environment. This work aims to investigate the prepared compatible mixed water (seawater and effluent water) response to nanoparticles for EOR water injection. The evaluation of different mix seawater/effluent water ratios (60/40,70/30) for their characteristics prior to nanofluid preparation using Inductive Couple Plasma (ICP) analysis, potential zeta test, and OLI software (the OLI Systems is a recognised leader in aqueous chemistry). This step of the work revealed the suitability of the water mix with a lower effluent-water ratio. Also, OLI predicted that the 60:40 mix needs to be balanced around temperatures of 70 ºC to avoid the mass accumulation of calcium sulfate and strontium sulfate. Later the prepared nanofluid was tested for interfacial tension (IFT) and wettability restoration in the sandstone rock; the Al2O3 nanofluid at 0.06 wt% concentration reduced the IFT by more than 16% with moderate water wet contact angle. The study concluded that the selected nanoparticle Al2O3 had demonstrated excellent performance in decreasing the interfacial tension with respect to the selected water mix type (60/40) at low nanoparticles wt%.

Keywords: nano AL2O3, sanstone, nanofluid, IFT, wettability

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Authors: V. R. Ahire, A. Kumar, B. N. Pandey, K. P. Mishra, G. R. Kulkarni

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Radiation therapy is an effective vital strategy used globally in the treatment of cervical cancer. However, radiation efficacy principally depends on the radiosensitivity of the tumor, and not all patient exhibit significant response to irradiation. A radiosensitive tumor is easier to cure than a radioresistant tumor which later advances to local recurrence and metastasis. Herbal polyphenols are gaining attention for exhibiting radiosensitization through various signaling. Current work focuses to study the radiosensitization effect of ellagic acid (EA), on HeLa cells. EA intermediated radiosensitization of HeLa cells was due to the induction γ-H2AX foci formation, G1 phase cell cycle arrest, and loss of reproductive potential, growth inhibition, drop in the mitochondrial membrane potential and protein expression studies that eventually induced apoptosis. Irradiation of HeLa in presence of EA (10 μM) to doses of 2 and 4 Gy γ-radiation produced marked tumor cytotoxicity. EA also demonstrated radio-protective effect on normal cell, NIH3T3 and aided recovery from the radiation damage. Our results advocate EA to be an effective adjuvant for improving cancer radiotherapy as it displays striking tumor cytotoxicity and reduced normal cell damage instigated by irradiation.

Keywords: apoptotic radiosensitivity, ellagic acid, mitochondrial potential, cell-cycle arrest

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Authors: Hossam El-Sayed Emam

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As an essential issue for life, water while it’s important for all living organisms. However, the world is dangerously facing the serious problem for the deficiency of the sources of drinking water. Within the aquatic systems, there are various gases, microbes, and other toxic ingredients (chemical compounds and heavy metals) occurred owing to the draining of agricultural and industrial wastewater, resulting in water pollution. On the other hand, fuel (gaseous, liquid, or in solid phase) is one of the extensively consumable energy sources, and owing to its origin from fossil, it contains some sulfur-, nitrogen- and oxygen-based compounds that cause serious problems (toxicity, catalyst poisoning, corrosion, and gum formation andcarcinogenic effects), to be ascribed as undesirable pollutants.MOFs as porous coordinating polymers are superiorly exploited in the adsorption and separationof contaminants for wastewater treatment and fuel purification. The inclusion of highly adsorbent materials like MOFs to be immobilized within cellulosic materialscould be investigated as a new challenge for the separation of contaminants with high efficiency and opportunity for recyclability. Therefore, the current approach ascribes the exploitation of different MOFsimmobilized within cellulose (powder, films, and fabrics)for applications in environmental. Herein, using cellulose containing MOFs in dye removal (degradation and adsorption), pharmaceutical intermediates removal, and fuel purification were summarized.

Keywords: cellulose, MOFs, dye removal, pharmaceutical intermediates, fuel purification

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Authors: Majid Farsadrooh, Najmeh Sabbaghi, Seyed Mohammad Mostashari, Abolhasan Moradi

Abstract:

Phenolic compounds are chief environmental contaminants on account of their hazardous and toxic nature on human health. The preparation of sensitive and potent chemosensors to monitor emerging pollution in water and effluent samples has received great consideration. A novel and versatile nanocomposite sensor based on poly pyrogallol is presented for the first time in this study, and its electrochemical behavior for simultaneous detection of hydroquinone (HQ), catechol (CT), and resorcinol (RS) in the presence of nitrite is evaluated. The physicochemical characteristics of the fabricated nanocomposite were investigated by emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET). The electrochemical response of the proposed sensor to the detection of HQ, CT, RS, and nitrite is studied using cyclic voltammetry (CV), chronoamperometry (CA), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The kinetic characterization of the prepared sensor showed that both adsorption and diffusion processes can control reactions at the electrode. In the optimized conditions, the new chemosensor provides a wide linear range of 0.5-236.3, 0.8-236.3, 0.9-236.3, and 1.2-236.3 μM with a low limit of detection of 21.1, 51.4, 98.9, and 110.8 nM (S/N = 3) for HQ, CT and RS, and nitrite, respectively. Remarkably, the electrochemical sensor has outstanding selectivity, repeatability, and stability and is successfully employed for the detection of RS, CT, HQ, and nitrite in real water samples with the recovery of 96.2%–102.4%, 97.8%-102.6%, 98.0%–102.4% and 98.4%–103.2% for RS, CT, HQ, and nitrite, respectively. These outcomes illustrate that poly pyrogallol is a promising candidate for effective electrochemical detection of dihydroxybenzene isomers in the presence of nitrite.

Keywords: electrochemical sensor, poly pyrogallol, phenolic compounds, simultaneous determination

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Authors: Shirin jalili, Hadi Shirzad, Samaneh Nabavi, Somayeh Khanjani

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Biosensors in forensic analysis are ideal biological tools that can be used for rapid and sensitive initial screening and testing to detect of suspicious components like biological and chemical agent in crime scenes. The wide use of different biomolecules such as proteins, nucleic acids, microorganisms, antibodies and enzymes makes it possible. These biosensors have great advantages such as rapidity, little sample manipulation and high sensitivity, also Because of their stability, specificity and low cost they have become a very important tool to Forensic analysis and detection of crime. In crime scenes different substances such as rape samples, Semen, saliva fingerprints and blood samples, act as a detecting elements for biosensors. On the other hand, successful fluid recovery via biosensor has the propensity to yield a highly valuable source of genetic material, which is important in finding the suspect. Although current biological fluid testing techniques are impaired for identification of body fluids. But these methods have disadvantages. For example if they are to be used simultaneously, Often give false positive result. These limitations can negatively result the output of a case through missed or misinterpreted evidence. The use of biosensor enable criminal researchers the highly sensitive and non-destructive detection of biological fluid through interaction with several fluid-endogenous and other biological and chemical contamination at the crime scene. For this reason, using of the biosensors for detecting the biological fluid found at the crime scenes which play an important role in identifying the suspect and solving the criminal.

Keywords: biosensors, forensic analysis, biological fluid, crime detection

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Authors: Ralph Gruber, Martina Hafner, Theresia Greunz, Christian Reisecker, David Stifter

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The application of dry lubricant on aluminium for automotive industry is indispensable for a high-quality forming behaviour. To provide a short production time those forming aids will not be removed during the joining step. The aim of this study was the characterization of the influence of dry lubricants on the bond strength and the corrosion resistance of an 6xxx aluminium alloy for automotive applications. For this purpose, samples with a well-defined surface were lubricated with 1 g/m² dry lubricant and joined with a commercial thermosetting 1K-epoxy structural adhesive. The bond strength was characterized by means of lap shear test. To evaluate the corrosion resistance of the adhered aluminium samples an immersion test in 5 w% NaCl-solution was used. Based on fracture pattern analysis, the corrosion behaviour could be described. Dissolved corrosion products were examined using ICP-MS and NMR. By means of SEM/EDX the elementary composition of precipitated solids was determined. The results showed a dry lubricant independent bond strength for standard testing conditions. However, a significant effect of the forming aid, regarding the corrosion resistance of adhered aluminium samples against corrosive infiltration of the metal-adhesive-interface, was observed

Keywords: aluminium alloys, dry film lubricants, automotive industry, adhesive bonding, corrosion

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Authors: Charmaine Lamiel, Van Hoa Nguyen, Marjorie Baynosa, Jae-Jin Shim

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The depletion of non-renewable sources had led to the continuous development of various energy storage systems in order to cope with the world’s demand in energy. Supercapacitors have attracted considerable attention because they can store more energy than conventional capacitors and have higher power density than batteries. The combination of carbon-based material and metal chalcogenides are now being considered in response to the search for active electrode materials exhibiting high electrochemical performance. In this study, a hierarchical mesoporous carbon sphere@nickel cobalt sulfide (CS@Ni-Co-S) core-shell was synthesized using a simple hydrothermal method. The CS@Ni-Co-S core-shell microstructures exhibited a high capacitance of 724.4 F g−1 at 2 A g−1 in a 6 M KOH electrolyte. Good specific retention of 86.1% and high Coulombic efficiency of 97.9% was obtained after 2000 charge-discharge cycles. The electrode exhibited a high energy density of 58.0 Wh kg−1 (1440 W kg−1) and high power density of 7200 W kg−1 (34.2 Wh kg−1). The reaction involved green synthesis without further sulfurization or post-heat treatment. Through this study, a cost-effective and facile synthesis of CS@Ni-Co-S as an active electrode showed favorable electrochemical performance.

Keywords: carbon sphere, electrochemical, hydrothermal, nickel cobalt sulfide, supercapacitor

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Authors: Yi Zheng

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Improving formability and mechanical properties have always been one of the challenges in the field of additive manufacturing (AM) of nickel-based superalloys. In this work, the effect of a coaxially coupled alternating magnetic field (AMF) on surface morphology and mechanical properties of plasma arc-based additive manufactured Inconel 718 deposit were investigated. Results show that the Lorentz force induced by AMF strongly alters the flow behavior of the plasma jet and the molten pool, suppressing the tendency of the liquid metal in the molten pool to flow down on the two sides face of the deposit, which in turn remarkably improved the surface accuracy of the thin-walled deposit. Furthermore, the electromagnetic stirring induced by AMF can effectively enhance the convection between the dendrites, which could not only contribute to the formation of finer dendrites but also alleviate the enrichment of the elements (i.e., Nb and Mo) at the solid-liquid interface and inhibits the precipitation of Laves phase. The smallest primary dendritic arm spacing (~13 μm) and lowest Laves phases area fraction (3.12%) were witnessed in the bottom region of the AMF-assisted deposit. The mechanical test confirmed that the deposit's micro-hardness and tensile properties were moderately improved compared with the counterpart without AMF.

Keywords: additive manufacturing, inconel 718, alternating magnetic field, laves phase

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Authors: Anthony Okechukwu Ifediniru, Austin Ikechukwu Gbasouzor, Isidore Uche Uju

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This article is centered on the design, analysis, construction, and test of a locally made arc welding machine that operates on 250vac with 8 amp output taps ranging from 60vac to 250vac at a fixed frequency, which is of benefit to urban areas; while considering its cost-effectiveness, strength, portability, and mobility. The welding machine uses a power supply to create an electric arc between an electrode and the metal at the welding point. A current selector coil needed for current selection is connected to the primary winding. Electric power is supplied to the primary winding of its transformer and is transferred to the secondary winding by induction. The voltage and current output of the secondary winding are connected to the output terminal, which is used to carry out welding work. The output current of the machine ranges from 110amps for low current welding to 250amps for high current welding. The machine uses a step-down transformer configuration for stepping down the voltage in order to obtain a high current level for effective welding. The welder can adjust the output current within a certain range. This allows the welder to properly set the output current for the type of welding that is being performed. The constructed arc welding machine was tested by connecting the work piece to it. Since there was no shock or spark from the transformer’s laminated core and was successfully used to join metals, it confirmed and validated the design.

Keywords: AC current, arc welding machine, DC current, transformer, welds

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Authors: Rakesh Hajiyani, Chetan Chauhan, Harshkant Jethva, Mihir Joshi

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Metal bis-thiourea type organo-metallic crystals are popular as non-linear optical materials. Bis-thiourea nickel barium chloride was synthesized and crystals were grown by slow aqueous solvent evaporation technique. The transparent and colorless crystals having maximum dimensions of 13 mm x 8 mm x 2.2 mm were obtained. The EDAX was carried out to estimate the content of nickel and barium in the grown crystals. The powder XRD analysis suggested orthorhombic crystal structure with unit cell parameters as: a= 9.70 Å, b= 10.68 Å and c= 17.95 Å. The FTIR spectroscopy study confirmed the presence of various functional groups. The UV-vis spectroscopy study indicated that the crystals were transparent in the visible region with 90% transmittance level further optical parameters were studied. From the TGA it was found that the crystals remained stable up to 170 0C and then decomposed through two decomposition stages. The dielectric study was carried out in the frequency range of applied field from 500 Hz to 1 MHz. The variations of dielectric constant, dielectric loss were studied with frequency. It was found that the dielectric constant and the dielectric loss decreased as the frequency of applied field increased. The results are discussed.

Keywords: crystal growth, dielectric study, optical parameters, organo-metallic crystals, powder xrd, slow evaporation technique, TGA

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Authors: Masoumeh Kazemi

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Depression is one of the most common mental disorders that damage mental health. In addition to mental distress, mental health damage affects other dimensions of human health, including physical and social health. According to the national study of diseases and injuries in Iran, the third health problem of the country is depression. The purpose of this study was to measure the level of depression in people referred to Karaj psychiatric treatment centers, and to investigate the relationship between depression and drug and alcohol consumption. The statistical population included 5000 people. Morgan table was used to determine the sample size. The research questions sought to identify the relationship between depression and factors such as drug and alcohol use, employment and marital status, and gender. Beck standard questionnaire was used to collect complete information. Cronbach's alpha coefficient was used to confirm the reliability of the questionnaire. To test research hypotheses, non-parametric methods of correlation coefficient, Spearman's rank, Mann-Whitney and Kruskal-Wallis tests were used. The results of using SPSS statistical software showed that there is a direct relationship between depression and drug and alcohol use. Also, the rate of depression was higher in women, widows and unemployed people. Finally, by conducting the present study, it is suggested that people use the following treatments in combination for effective recovery: 1. Cognitive Behavioral Therapy (CBT) 2. Interpersonal Therapy (IPT) 3. Treatment with appropriate medication 4. Special light therapy 5. Electric shock treatment (in acute and exceptional cases) 6. Self-help

Keywords: alcohol, depression, drug, Iran

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Authors: Ayed S. Al-Shihri, Abul Kalam, Abdullah G. Al-Sehemi, Gaohui Du, Tokeer Ahmad, Ahmad Irfan

Abstract:

We report here the synthesis of nickel oxide (NiO) nanoparticles by microwave-assisted method, using a common precipitating agent followed by calcination in air at 400°C. The effect of the microwave and pH on the crystallite size, morphology, structure, energy band gap and surface area of NiO have been investigated by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV-vis) and BET surface area studies. X-ray diffraction studies showed the formation of monophasic and highly crystalline cubic NiO. TEM analysis led to decrease the average grain size of NiO nanoparticles from 16.5 nm to 14 nm on increasing the amount of NaOH. FTIR studies also confirm the formation of NiO nanoparticles. It was observed that on increasing the volume of NaOH, the optical band gap energy (2.85 eV to 2.95 eV) and specific surface area (33.1 to 39.8 m2/g) increases, however the average particles size decreases (16.5 nm to 14 nm). This method may be extended to large scale synthesis of other metal oxides nanoparticles and the present study could be used for the potential applications in water treatment and many other fields.

Keywords: BET surface area analysis, electron microscopy, optical properties, X-ray techniques

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Authors: Jamuna Rajeswaran

Abstract:

In the past two decades, with a population of more than a billion. India is passing through a major socio-demographic and epidemiological transition with consequent changes in health scenario. TBI constitute significant burden on health care resources in India The impact on a person and family can be devastating. Patients with TBI experience persistent cognitive deficits, emotional changes, which contribute to the disruption of life activities. The recovery of TBI would be maximized by appropriate rehabilitation. Neurofeedback is an emerging neuroscience-based clinical application. Sixty patients were recruited for this study after obtaining informed consent. Rivermead Head Injury Follow-up Questionnaire, Rivermead Post Concussion Symptoms Questionnaire and Visual Analog Scale were used to assess the behavioral and symptomotolgy associated with post TBI. Neuropsychological assessment was carried out using NIMHANS neuropsychological battery 2004. The Intervention group received neurofeedback training and the waitlist group did not receive any treatment during this phase. Patients were allocated to intervention and waitlist group at random. There were 30 patients in each group. Patients were given 20 sessions of NFT Patients were trained on the O1 and O2 channels for alpha theta training. Each session was of 40 minutes duration with 5-6 sessions per week. The post-training assessment was carried out for the intervention group after 20 sessions of NFT. The waitlist group underwent assessment after one month. Results showed neurofeedback training is effective in ameliorating deficits in cognitive functions and quality of life in patients with TBI. Improvements were corroborated by the clinical interview with patients and significant others post NFT.

Keywords: assessment, rehabilitation, cognition, EEG neurofeedback

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Authors: Mercedeh Malekzadeh

Abstract:

Scrap tires are the source of wastes that cause the environmental problems. The major components of these tires are rubber and carbon black. These components can be used again for different applications by utilizing physical and chemical processes. Pyrolysis is a way that converts rubber portion of scrap tires to oil and gas and the carbon black recovers to pyrolytic carbon black. This pyrolytic carbon black can be used to reinforce rubber and metal, coating preparation, electronic thermal manager and so on. The porous structure of this carbon black also makes it as a suitable choice for heavy metals removal from water. In this work, the application of base treated pyrolytic carbon black was studied as an adsorbent for chromium (III) removal from water in a batch process. Pyrolytic carbon blacks in two natural and base treated forms were characterized by scanning electron microscopy and energy dispersive analysis x-ray. The effects of adsorbent dosage, contact time, initial concentration of chromium (III) and pH were considered on the adsorption process. The adsorption capacity was 19.76 mg/g. Maximum adsorption was seen after 120 min at pH=3. The equilibrium data were considered and better fitted to Langmuir model. The adsorption kinetic was evaluated and confirmed with the pseudo second order kinetic. Results have shown that the base treated pyrolytic carbon black obtained from scrap tires can be used as a cheap adsorbent for removal of chromium (III) from the water.

Keywords: chromium (III), pyrolytic carbon, scrap tire, water

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Authors: Abdulmagid A. Khattabi, Abdul Fatah M. Emhamed

Abstract:

The steel alloy Introduced after becoming carbon-steel does not meet the requirements of engineering industry; and it cannot be obtained tensile strength from carbon-steel higher than (700MPa), the low alloy steel enters in a lot of heavy engineering equipment parts, molds, agricultural equipment and other industry. In addition, that may be exposed to in-service failure, which may require returned to work, to do the repairs or maintenance by one of the welding methods available. The ability of steel weld determined through palpation of the cracks, which can reduce by many ways. These ways are often expensive and difficult to implement, perhaps the control to choose the type of electrode welding user is one of the easiest and least expensive applications. It has been welding the steel low alloys high resistance by manual metal arc (MMA), and by using a set of welding electrodes which varying in chemical composition and in their prices as well and test their effect on tensile strength. Results showed that using the poles of welding, which have a high proportion of iron powder and low hydrogen. The Tensile resistance is (484MPa) and the weld joint efficiency was (56.9%), but when (OK 47.04) electrode was used the tensile strength increased to (720MPa) and the weld joint efficiency to (84.7%). Using the cheapest electrode (OK 45.00) the weld joint efficiency did not exceed (24.2%), but when using the most expensive electrode (OK 91.28) the weld joint efficiency is (38.1%).

Keywords: steel low alloys high resistance, electrodes welding, tensile test

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Authors: Yogi Priyo Pradana, Heriansyah Putra, Regina Aprilia Zulfikar, Maulana Rafiq Ramadhan, Devyan Meisnnehr, Zalfa Maulida Insani

Abstract:

This paper studied the effects and mechanisms of fine-grained tailing by Enzyme-Mediated Calcite Precipitation (EMCP). Grouting solution used consists of reagents (CaCl₂ and (CO(NH₂)₂) and urease enzymes which react to produce CaCO₃. In sample preparation, the test tube is used to investigate the precipitation rate of calcite. The grouting solution added is 75 mL for one mold sample. The solution was poured into a mold sample up to as high as 5 mm from the top surface of the tailing to ensure the entire surface is submerged. The sample is left open in a cylinder for up to 3 days for curing. The direct mixing method is conducted so that the cementation process occurs by evenly distributed. The relationship between the results of the UCS test and the calcite precipitation rate likely indicates that the amount of calcite deposited in treated tailing could control the strength of the tailing. The sample results are analyzed using atomic absorption spectroscopy (AAS) to evaluate metal and metalloid content. Calcium carbonate deposited in the tailing is expected to strengthen the bond between tailing granules, which are easily slipped on the banks of the tailing dam. The EMCP method is expected to strengthen tailing in erosion-control surfaces.

Keywords: tailing, EMCP, UCS, AAS

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Authors: Leonce Dusengemungu

Abstract:

Filamentous fungi indigenous to heavy metals (HMs) contaminated environments have a considerable biosorption potential yet are currently under-investigated in developing countries. In the work presented herein, the biosorption potential of three indigenous filamentous fungi (Aspergillus transmontanensis, Cladosporium cladosporioides, and Geotrichum candidum) isolated from copper and cobalt mining wasteland sites in Zambia's Copperbelt province was investigated. In Cu and Co tolerance tests, all the fungal isolates were shown to be tolerant, with mycelial growth at HMs concentrations of up to 7000 ppm. However, exposure to high Cu and Co concentrations hindered the growth of the three strains to varying degrees, resulting in reduced mycelial biomass (evidenced by loss of the infrared bands at 887 and 930 cm-1 of the 1,3-glucans backbone) as well as morphological alterations, sporulation, and pigment synthesis. In addition, gas chromatography-mass spectrometry characterization of the fungal biomass extracts allowed to detect changes in the chemical constituents upon exposure to HMs, with profiles poorer in maltol, 1,2-cyclopentadione, and n-hexadecanoic acid, and richer in furaldehydes. Biosorption tests showed that A. transmontanensis and G. candidum showed better performance as bioremediators than C. cladosporioides, with biosorption efficiencies of 1645, 1853 and 1253 ppm at pH 3, respectively, and may deserve further research in field conditions.

Keywords: bioremediation, fungi, biosorption, heavy metal

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Authors: Hassan S. Naeini

Abstract:

Nowadays a lot of people are working in several sorts of industrial sectors in which there are some risk factors which threaten human being especially in developing countries. One of the main problems which effect on workers’ health refers to Ergonomics. Ergonomics as multidisciplinary science concerns workers’ health and safety in terms of somatic and mental concepts. Surely ergonomics interventions and improvement make a better condition for workers and change the quality of working life to better condition. In this study, one of the factories in Iran which is producing some kinds of small and medium size of refrigerators was chosen as the sample. The preliminary ergonomics observation of the mentioned factory showed that there are some risk factors in terms of ergonomics aspects, so an ergonomic intervention was defined, then some ergonomic assessment methods such as NMQ,OWAS, and Environmental Ergonomic Assessment were used. Also Anthropometric measurement was done. This study shows that there are some workstations and plants which suffer some degrees of ergonomic problems. Considering with the gathered data, illumination, noise control and workstation design in metal workstation are known as the priority actions. Some parts of the mentioned interventions are ongoing actions. it seems that the mentioned intervention and workstations design make a better condition for workers, because ergonomics make a safer and more sustainable environments for human being.

Keywords: anthropometry, ergonomics, health, NMQ, OWAS

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