Search results for: maximum pressure

Authors: Jaber Shurrab, Matloub Hussain

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The rapid pace of changes in the construction industry, technological advancements, and rising costs present tremendous challenges for project managers. Project managers are under severe pressure to minimize the waste, improve the efficiency of the entire operations and the philosophy of ‘lean thinking’ so that ‘more could be achieved with less’ is becoming very popular. Though, lean management has strong roots in manufacturing industry and over the last decade lean philosophy has started gaining attention in the service industry as well. However, little has been known in the context of waste minimization and lean implementation in the construction industry and this paper deals with this important issue. The primary objective of this paper is to propose a conceptual framework for the exploration of appropriate lean techniques applicable to medium and large construction companies and measure their impact on the competitiveness and economic performance of construction companies of United Arab Emirates (UAE). To this end, a comprehensive literature review and interviews with eight project managers of medium and large construction companies of UAE have been conducted. It has been found that competitive, reduce waste and costs are critical to the construction industry. This is an ongoing research in lean management, giving project managers a practical framework for improving the efficiency of their project through various lean techniques. Originality/value: Research significance emphasizes increasing the effectiveness of the construction industry, influences the development of lean construction framework which improves lean construction practices using the lean techniques. This contributes to the effort of applying lean techniques in the construction industry. Limited publications were done in the construction industry mainly in United Arab Emirates (UAE) compared to the lean manufacturing. This research will recommend a systematic approach for the implementing of the anticipated framework within a cyclical look-ahead period and emphasizes the practical implications of the proposed approach.

Keywords: construction, lean, lean manufacturing, waste

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Authors: Egor Atan Obeten, Abong Augustine Agwul, Bissong A. Samson

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The position of the aquifer, its protective capability, and the quality of the groundwater beneath the dumpsite were all investigated. The techniques employed were laboratory, tritium tagging, electrical resistivity tomography (ERT), and vertical electrical sounding (VES). With a maximum electrode spacing of 500 meters, fifteen VES stations were used, and IPI2win software was used to analyze the data collected. The resistivity map of the dumpsite was determined by deploying six ERT stations for the 2 D survey. To ascertain the degree of soil infiltration beneath the dumpsite, the tritium tagging method was used. Using a conventional laboratory procedure, groundwater samples were taken from neighboring boreholes and examined. The findings showed that there were three to five geoelectric layers, with the aquifer position being inferred to be between 24.2 and 75.1 meters deep in the third, fourth, and fifth levels. Siemens with values in the range of 0.0235 to 0.1908 for the load protection capacity were deemed to be, at most, weakly and badly protected. The obtained porosity values ranged from 44.45 to 89.75. Strong calculated values for transmissivity and porosity indicate a permeable aquifer system with considerable storativity. The area has an infiltration value between 8 and 22 percent, according to the results of the tritium tagging technique, which was used to evaluate the level of infiltration from the dumpsite. Groundwater samples that have been analyzed reveal levels of NO2, DO, Pb2+, magnesium, and cadmium that are higher than what the NSDWQ has approved. Overall analysis of the results from the above-described methodologies shows that the study area's aquifer system is porous and that contaminants will circulate through it quickly if they are contaminated.

Keywords: aquifer, transmissivity, dumpsite, groundwater

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Authors: Hana Aljumayi, Mohammed Issa

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The aim of this study was to investigate the effect of the training program for professional athletes at the Saudi Archery Federation on the electrical activity of the muscles involved in pulling the bowstring, maximum muscle strength (MVC) and to identify the relationship between the electrical activity of these muscles and accuracy in shooting among female archers. The researcher used a descriptive approach that was suitable for the nature of the study, and a sample of nine female archers was selected using purposive sampling. An EMG device was used to measure signal amplitude, signal frequency, spectral energy signal, and MVC. The results showed statistically significant differences in signal amplitude among muscles, with F(8,1)=5.91 and a significance level of 0.02. There were also statistically significant differences between muscles in terms of signal frequency, with F(8,1)=8.23 and a significance level of 0.02. Bonferroni test results indicated statistically significant differences between measurements at a significance level of 0.05, with anterior measurements showing an average difference of 16.4 compared to other measurements. Furthermore, there was a significant negative correlation between signal amplitude in the calf muscle and accuracy in shooting (r=-0.78) at a significance level of 0.02. There was also a significant positive correlation between signal frequency in the calf muscle and accuracy in shooting (r=0.72) at a significance level of 0.04. In conclusion, it appears that the training program for archery athletes focused more on skill development than physical aspects such as muscle activity and strength development. However, it did have a statistically significant effect on signal amplitude but not on signal frequency or MVC development in muscles involved in pulling the bowstring.

Keywords: electrical activity of muscles, archery sport, shooting accuracy, muscles

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Authors: Anjali Suresh

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Kerala is well known for its unique settlement pattern; comprising the most part, a continuous spread of habitation. The notable urbanization trend in Kerala is urban spread rather than concentration which points out the increasing urbanization of peripheral areas of existing urban centers. This has thrown a challenge for the authorities to cater the needs of the urban population like to provide affordable housing and infrastructure facilities to sustain their livelihood; which is a matter of concern that needs policy attention in fixing the optimum FSI value. Based on recent reports (Post Disaster Need Analysis –PDNA) from the UN, addressing the unsafe situation of the carpet FAR/FSI practice in the state showcasing the varying geological & climatic conditions should also be the matter of concern. The FSI (Floor space index- the ratio of the built-up space on a plot to the area of the plot) value is certainly one of the key regulation factors in checking the land utilization for the varying occupancies desired for the overall development of a state with limitation in land availability when compared to its neighbors. The pattern of urbanization, physical conditions, topography, etc., varies within the state and can change remarkably over time which identifies that the practicing FSI norms in Kerala does not fulfils the intended function. Thus the FSI regulation is expected to change dynamically from location to location. So for determining the optimum value of FSI /FAR of a region in the state of Kerala, the government agencies should consider the optimum land utilization for the growing urbanization. On the other hand, shall keep in check the overutilization of the same in par with environmental and geographic nature. Therefore the study identifies parameters that should be considered for assigning FSI within the Kerala context, and through expert surveys; opinions arrive at a methodology for assigning an optimum FSI value of a region in the state of Kerala.

Keywords: floor space index, urbanization, density, civic pressure, optimization

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Authors: Akilah A. Jardine

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The integration and expansion of the global economy have indeed brought about a number of positive changes such as access to new goods and services and the opportunity for individuals and businesses to migrate, communicate, and work globally. Nevertheless, the interconnectedness of world economies is not without its negative and shameful side effects. The subsequent overabundance of goods and services has resulted in heightened competition among firms and their supply chains, fuelling the exploitation of impoverished and vulnerable individuals who are unable to equally salvage from the benefits of the integrated economy. To maintain their position in a highly competitive arena, the operations of many businesses have adopted unethical and unscrupulous practices to maximise profit, often targeting the most marginalised members of society. Simultaneously, in a consumerist obsessed society preoccupied with the consumption and accumulation of material wealth, the demand for goods and services greatly contributes to the pressure on firms, thus bolstering the exploitation of labour. This paper aims to examine the impact of business operations on the practice of labour exploitation. It explores corrupt business practices that firms adopt and key labour exploitative conditions outlined by the International Labour Organization, particularly, paying workers low wages, forcing individuals to work in abusive and unsafe conditions, and considers the issue regarding individuals’ consent to exploitative environments. Further, it considers the role of consumers in creating the high demand for goods and services, which in turn fosters the exploitation of labour. This paper illustrates that the practice of labour exploitation in the economy is a by-product of both global competitive business operations and heightened consumer consumption.

Keywords: globalisation, labour exploitation, modern slavery, sweatshops, unethical business practices

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Authors: Elena Petersen, Inna Kornienko, Svetlana Guryeva, Sergey Dobdin, Anatoly Skripal, Andrey Usanov, Dmitry Usanov

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One of the most important unsolved problems in modern medicine is the increase of chronic diseases that lead to organ dysfunction or even complete loss of function. Current methods of treatment do not result in decreased mortality and disability statistics. Currently, the best treatment for many patients is still transplantation of organs and/or tissues. Therefore, finding a way of correct artificial matrix biofabrication in case of limited number of natural organs for transplantation is a critical task. One important problem that needs to be solved is development of a nondestructive and noninvasive method to analyze dynamic changes of mechanical characteristics of a matrix with minimal side effects on the growing cells. This research was focused on investigating the properties of matrix as a marker of graft condition. In this study, the collagen gel with human primary dermal fibroblasts in suspension (60, 120, 240*103 cells/mL) and collagen gel with cell spheroids were used as model objects. The stiffness and elasticity characteristics were evaluated by a semiconductor laser autodyne. The time and cell concentration dependency of the stiffness and elasticity were investigated. It was shown that these properties changed in a non-linear manner with respect to cell concentration. The maximum matrix stiffness was observed in the collagen gel with the cell concentration of 120*103 cells/mL. This study proved the opportunity to use the mechanical properties of matrix as a marker of graft condition, which can be measured by noninvasive semiconductor laser autodyne technique.

Keywords: graft, matrix, noninvasive method, regenerative medicine, semiconductor laser autodyne

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Authors: Judith Stein, Elfriede Friedmann

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The injection of a drug into the vitreous body for the treatment of retinal diseases like wet aged-related macular degeneration (AMD) is the most common medical intervention worldwide. We develop mathematical models for drug transport in the vitreous body of a human eye to analyse the impact of different rheological models of the vitreous on drug distribution. In addition to the convection diffusion equation characterizing the drug spreading, we use porous media modeling for the healthy vitreous with a dense collagen network and include the steady permeating flow of the aqueous humor described by Darcy's law driven by a pressure drop. Additionally, the vitreous body in a healthy human eye behaves like a viscoelastic gel through the collagen fibers suspended in the network of hyaluronic acid and acts as a drug depot for the treatment of retinal diseases. In a completely liquefied vitreous, we couple the drug diffusion with the classical Navier-Stokes flow equations. We prove the global existence and uniqueness of the weak solution of the developed initial-boundary value problem describing the drug distribution in the healthy vitreous considering the permeating aqueous humor flow in the realistic three-dimensional setting. In particular, for the drug diffusion equation, results from the literature are extended from homogeneous Dirichlet boundary conditions to our mixed boundary conditions that describe the eye with the Galerkin's method using Cauchy-Schwarz inequality and trace theorem. Because there is only a small effective drug concentration range and higher concentrations may be toxic, the ability to model the drug transport could improve the therapy by considering patient individual differences and give a better understanding of the physiological and pathological processes in the vitreous.

Keywords: coupled PDE systems, drug diffusion, mixed boundary conditions, vitreous body

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Authors: Shima Soleimani, Steven Eckels

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One area of special importance for surface-level study of heat exchangers is tubes with internal micro-fins (< 0.5 mm tall). Micro-finned surfaces are a kind of extended solid surface in which energy is exchanged with water that acts as the source or sink of energy. Significant performance gains are possible for either shell, tube, or double pipe heat exchangers if the best surfaces are identified. The parametric studies of micro-finned tubes that have appeared in the literature left some key parameters unexplored. Specifically, they ignored three-dimensional (3D) micro-fin configurations, conduction heat transfer in the fins, and conduction in the solid surface below the micro-fins. Thus, this study aimed at implementing a parametric study of 3D micro-finned tubes that considered micro-fin height and discontinuity features. A 3D conductive and convective heat-transfer simulation through coupled solid and periodic fluid domains is applied in a commercial package, ANSYS Fluent 19.1. The simulation is steady-state with turbulent water flow cooling inner wall of a tube with micro-fins. The simulation utilizes a constant and uniform temperature on the tube outer wall. Performance is mapped for 18 different simulation cases, including a smooth tube using a realizable k-ε turbulence model at a Reynolds number of 48,928. Results compared the performance of 3D tubes with results for the similar two-dimensional (2D) one. Results showed that the micro-fin height has greater impact on performance factor than discontinuity features in 3D micro-fin tubes. A transformed 3D micro-fin tube can enhance heat transfer and pressure drop up to 21% and 56% compared to a 2D one, respectfully.

Keywords: three-dimensional micro-finned tube, heat transfer, friction factor, heat exchanger

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Authors: Michelle Nighswander

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Suicide can be a tragic response to mental illness. It is difficult for people to disclose or discuss suicidal impulses. The stigma surrounding mental health can create a reluctance to seek help for mental illness. Patients may feel pressure to exhibit a socially desirable demeanor rather than reveal these issues, especially if they sense their healthcare provider is pressed for time or does not have an extensive history with their provider. Overcoming these barriers can be challenging. Although there are several validated depression and suicide risk instruments, varying processes used to administer these tools may impact the truthfulness of the responses. A literature review was conducted to find evidence of the impact of the environment on the accuracy of depression screening. Many investigations do not describe the environment and fewer studies use a comparison design. However, three studies demonstrated that computerized self-reporting might be more likely to elicit truthful and accurate responses due to increased privacy when responding compared to a face-to-face interview. These studies showed patients reported positive reactions to computerized screening for other stigmatizing health conditions such as alcohol use during pregnancy. Computerized self-screening for depression offers the possibility of more privacy and patient reflection, which could then send a targeted message of risk to the healthcare provider. This could potentially increase the accuracy while also increasing time efficiency for the clinic. Considering the persistent effects of mental health stigma, how these screening questions are posed can impact patients’ responses. This literature review analyzes trends in depression screening methodologies, the impact of setting on the results and how this may assist in overcoming one barrier caused by stigma.

Keywords: computerized self-report, depression, mental health stigma, suicide risk

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Authors: Young-Min Kang

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M-type Sr-hexaferrites (SrFe12O19) is one of the most utilized materials in permanent magnets due to their low price, outstanding chemical stability, and appropriate hard magnetic properties. For a M-type Sr-hexaferrite with a saturation magnetization (MS) of ~74.0 emu/g the practical limits of remanent flux density (Br) and maximum energy product (BH) max are ~4.6 kG and ~5.3 MGOe. Meanwhile, W-type hexaferrite (SrFe18O27) with higher MS ~81emu/g can be a good candidate for the development of enhanced ferrite magnet. However the W-type hexaferrite is stable at the temperature over 1350 ºC in air, and thus it is hard to control grain size and the coercivity. We report here high-MS M-W composite hexaferrites synthesized at 1250 ºC in air by doping Ca, Co, Mn, and Zn into the hexaferrite structures. The hexaferrites samples of stoichiometric SrFe12O19 (SrM) and Ca-Co-Mn-Zn doped hexaferrite (Sr0.7Ca0.3Fen-0.6Co0.2Mn0.2Zn0.2Oa) were prepared by conventional solid state reaction process with varying Fe content (10 ≤ n ≤ 17). Analysis by x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) were performed for phase identification and microstructural observation respectively. Magnetic hysteresis curves were measured using vibrating sample magnetometer (VSM) at room temperature (300 K). Single M-type phase could be obtained in the non-doped SrM sample after calcinations at the range of 1200 ºC ~ 1300 ºC, showing MS in the range of 72 ~ 72.6 emu/g. The Ca-Co-Mn-Zn doped SrM with Fe content, 10 ≤ n ≤ 13, showed both M and W-phases peaks in the XRD after respective calcinations at 1250 ºC. The sample with n=13 showed the MS of 70.7, 75.3, 78.0 emu/g, respectively, after calcination at 1200, 1250, 1300 ºC. The high MS over that of non-doped SrM (~72 emu/g) is attributed to the volume portion of W-phase. It is also revealed that the high MS W-phase could not formed if only one of the Ca, Co, Zn is missed in the substitution. These elements are critical to form the W-phase at the calcinations temperature of 1250 ºC, which is 100 ºC lower than the calcinations temperature for non-doped Sr-hexaferrites.

Keywords: M-type hexaferrite, W-type hexaferrite, saturation magnetization, low-temperature synthesis

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Authors: Firas Rashad Al-Samarai

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Introduction: Benign prostatic hyperplasia (BPH) is a common condition as men get older. An enlarged prostate gland can cause uncomfortable urinary symptoms, such as blocking the flow of urine out of the bladder. It can also cause bladder, urinary tract, or kidney problems. Objective: to evaluate the efficacy and interaction of tamsulosin with finasteride treatment on induced benign prostate hyperplasia (BPH) in mice. Methods: BPH was induced by subcutaneous injection of testosterone propionate (20 mg/kg) for 30 days. Eighty-five mice were divided into five groups. The first group (G1): twenty-five mice induced BPH treated with tamsulosin orally and divided into five equal subgroups with doses (0.017, 0.052, 0.087, 0. 123, and 0.158) mg/kg, the second group (G2): twenty-five mice induced BPH treated with finasteride orally and divided into five equal subgroups with doses (0.175, 0.527, 0.878, 1.23, and 1.580) mg/kg. the third group (G3): twenty-five mice induced BPH treated with a combination of tamsulosin with finasteride orally, and divided into five equal subgroups with doses (0.0085, 0.0875), (0.026, 0.2635), (0.0435, 0.439) , (0.0615, 0.615) and ( 0.079 , 0.790 ) mg/kg respectively. Fourth group (G4): five mice induced BPH and treated distilled water. Fifth group (G5): five mice were not inducing BPH and without any treatment. Results: The results showed a gradual significant increase in prostate weight % and prostate index % Inhibitions until reached saturation in the last two doses of tamsulosin, finasteride, and combination groups, the maximum effective dose of tamsulosin and finasteride were (0.156) and (1.495) mg/kg respectively. Moreover, the effective dose of the combination (tamsulosin and finasteride) was estimated (0.06876, 0.6876) mg/kg, respectively, as well as the type of interaction was synergism and the value of the combination index was 0.046. Conclusions: We concluded that the combination of tamsulosin with finasteride showed a synergistic effect in BPH treatment by minimizing the side effect of each drug as s result of decreasing the dose of each one.

Keywords: Tamsulosin, Finasteride, combination, BPH

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Authors: Nazanin Sheibanian, Raffaella Sesana, Sedat Ozbilen

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In recent years, high-entropy alloys (HEAs) have attracted considerable attention due to their unique properties and potential applications. In this study, novel HEA coatings were prepared on Mg substrates using mechanically alloyed HEA powder feedstocks based on Al_(0.1-0.5)CoCrCuFeNi and MnCoCrCuFeNi multi-material systems. The coatings were deposited by the Cold Spray (CS) process using three different temperatures of the process gas (N2) (650°C, 750°C, and 850°C) to examine the effect of gas temperature on coating properties. In this study, Infrared Thermography (non-destructive) was examined as a possible quality control technique for HEA coatings applied to magnesium substrates. Active Thermography was employed to characterize coating properties using the thermal response of the coating. Various HEA chemical compositions and deposition temperatures have been investigated. As a part of this study, a comprehensive macro and microstructural analysis of Cold Spray (CS) HEA coatings has been conducted using macrophotography, optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM+EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), microhardness tests, roughness measurements, and porosity assessments. These analyses provided insight into phase identification, microstructure characterization, deposition, particle deformation behavior, bonding mechanisms, and identifying a possible relationship between physical properties and thermal responses. Based on the figures and tables, it is evident that the Maximum Relative Radiance (∆RMax) of each sample differs depending on both the chemical composition of HEA and the temperature at which Cold Spray is applied.

Keywords: active thermography, coating, cold spray, high- entropy alloy, material characterization

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Authors: Marek Pawlikowski, Krzysztof Jankowski, Konstanty Skalski, Anna Makuch

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Nanoindentation or depth-sensing indentation (DSI) technique has proven to be very useful to measure mechanical properties of various tissues at a micro-scale. Bone tissue, both trabecular and cortical one, is one of the most commonly tested tissues by means of DSI. Most often such tests on bone samples are carried out to compare the mechanical properties of lamellar and interlamellar bone, osteonal bone as well as compact and cancellous bone. In the paper, a relation between stress and strain for human trabecular bone is presented. The relation is based on the results of nanoindentation tests. The formulation of a constitutive model for human trabecular bone is based on nanoindentation tests. In the study, the approach proposed by Olivier-Pharr is adapted. The tests were carried out on samples of trabecular tissue extracted from human femoral heads. The heads were harvested during surgeries of artificial hip joint implantation. Before samples preparation, the heads were kept in 95% alcohol in temperature 4 Celsius degrees. The cubic samples cut out of the heads were stored in the same conditions. The dimensions of the specimens were 25 mm x 25 mm x 20 mm. The number of 20 samples have been tested. The age range of donors was between 56 and 83 years old. The tests were conducted with the indenter spherical tip of the diameter 0.200 mm. The maximum load was P = 500 mN and the loading rate 500 mN/min. The data obtained from the DSI tests allows one only to determine bone behoviour in terms of nanoindentation force vs. nanoindentation depth. However, it is more interesting and useful to know the characteristics of trabecular bone in the stress-strain domain. This allows one to simulate trabecular bone behaviour in a more realistic way. The stress-strain curves obtained in the study show relation between the age and the mechanical behaviour of trabecular bone. It was also observed that the bone matrix of trabecular tissue indicates an ability of energy absorption.

Keywords: constitutive model, mechanical behaviour, nanoindentation, trabecular bone

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Authors: G. Baranski, A. Majczak, M. Wendeker

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Currently, the most commonly used solution to provide fuel to the diesel engines is the Common Rail system. Compared to previous designs, as a due to relatively simple construction and electronic control systems, these systems allow achieving favourable engine operation parameters with particular emphasis on low emission of toxic compounds into the atmosphere. In this system, the amount of injected fuel dose is strictly dependent on the course of parameters of the electrical impulse sent by the power amplifier power supply system injector from the engine controller. The article presents the construction of a laboratory test bench to examine the course of the injection process and the expense in storage injection systems. The test bench enables testing of injection systems with electromagnetically controlled injectors with the use of scientific engineering tools. The developed system is based on LabView software and CompactRIO family controller using FPGA systems and a real time microcontroller. The results of experimental research on electromagnetic injectors of common rail system, controlled by a dedicated National Instruments card, confirm the effectiveness of the presented approach. The results of the research described in the article present the influence of basic parameters of the electric impulse opening the electromagnetic injector on the value of the injected fuel dose. Acknowledgement: This work has been realized in the cooperation with The Construction Office of WSK ‘PZL-KALISZ’ S.A.’ and is part of Grant Agreement No. POIR.01.02.00-00-0002/15 financed by the Polish National Centre for Research and Development.

Keywords: fuel injector, combustion engine, fuel pressure, compression ignition engine, power supply system, controller, LabVIEW

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Authors: Sarada Prasad Pradhan, Vikram Vishal, Tariq Siddique

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With a vast area of India comprising of hilly terrain and road cut slopes, landslides and rockfalls are a common phenomenon. However, while landslide studies have received much attention in the past in India, very little literature and analysis is available regarding rockfall hazard of many rockfall prone areas, specifically in Uttarakhand Himalaya, India. The subsequent lack of knowledge and understanding of the rockfall phenomenon as well as frequent incidences of rockfall led fatalities urge the necessity of conducting site-specific rockfall studies to highlight the importance of addressing this issue as well as to provide data for safe design of preventive structures. The present study has been conducted across 10 rockfall prone road cut slopes for a distance of 15 km starting from Devprayag, India along National Highway 58 (NH-58). In order to make a qualitative assessment of Rockfall Hazard posed by these slopes, Rockfall Hazard Rating using standards for Indian Rockmass has been conducted at 10 locations under different slope conditions. Moreover, to accurately predict the characteristics of the possible rockfall phenomenon, numerical simulation was carried out to calculate the maximum bounce heights, total kinetic energies, translational velocities and trajectories of the falling rockmass blocks when simulated on each of these slopes according to real-life conditions. As it was observed that varying slope geometry had more fatal impacts on Rockfall hazard than size of rock masses, several optimizations have been suggested for each slope regarding location of barriers and modification of slope geometries in order to minimize damage by falling rocks. This study can be extremely useful in emphasizing the significance of rockfall studies and construction of mitigative barriers and structures along NH-58 around Devprayag.

Keywords: rockfall, slope stability, rockmass, hazard

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Authors: Dhyaalddin Bahaalddin Noori Zangana

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This study involves the behavior of reinforced sand under a square footing. A series of bearing capacity tests were performed on a small-scale laboratory model, which filled with a poorly-graded homogenous bed of sand, which was placed in a medium dense state using sand raining technique. The sand was reinforced with 40 mm wide household aluminum foil strips. The main studied parameters was to consider the effect of reinforcing strip length, with various linear density of reinforcement, number of reinforcement layers and depth of top layer of reinforcement below the footing, on load-settlement behavior, bearing capacity ratio and settlement reduction factor. The relation of load-settlement generally showed similar trend in all the tests. Failure was defined as settlement equal to 10% of the footing width. The recommended optimum reinforcing strip length, linear density of reinforcement, number of reinforcement layers and depth of top layer of reinforcing strips that give the maximum bearing capacity improvement and minimum settlement reduction factor were presented and discussed. Different bearing capacity ration versus length of the reinforcing strips and settlement reduction factor versus length of the reinforcing strips relations at failure were showed improvement of bearing capacity ratio by a factor of 3.82 and reduction of settlement reduction factor by a factor of 0.813. The optimum length of reinforcement was found to be 7.5 times the footing width.

Keywords: square footing, relative density, linear density of reinforcement, bearing capacity ratio, load-settlement behaviour

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Authors: Kevin Giraldo, Juan A. Gallego, Uriel Zapata, Fanny L. Casado

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Compliant mechanisms are designed to deform in a controlled manner in response to external forces, utilizing the flexibility of their components to store potential elastic energy during deformation, gradually releasing it upon returning to its original form. This article explores the design of a knee orthosis intended to assist users during stand-up motion. The orthosis makes use of a compliant mechanism to balance the user’s weight, thereby minimizing the strain on leg muscles during standup motion. The primary function of the compliant mechanism is to store and exchange potential energy, so when coupled with the gravitational potential of the user, the total potential energy variation is minimized. The design process for the semi-rigid knee orthosis involved material selection and the development of a numerical model for the compliant mechanism seen as a spring. Geometric properties are obtained through the numerical modeling of the spring once the desired stiffness and safety factor values have been attained. Subsequently, a 3D finite element analysis was conducted. The study demonstrates a strong correlation between the maximum stress in the mathematical model (250.22 MPa) and the simulation (239.8 MPa), with a 4.16% error. Both analyses safety factors: 1.02 for the mathematical approach and 1.1 for the simulation, with a consistent 7.84% margin of error. The spring’s stiffness, calculated at 90.82 Nm/rad analytically and 85.71 Nm/rad in the simulation, exhibits a 5.62% difference. These results suggest significant potential for the proposed device in assisting patients with knee orthopedic restrictions, contributing to ongoing efforts in advancing the understanding and treatment of knee osteoarthritis.

Keywords: biomechanics, complaint mechanisms, gonarthrosis, orthoses

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Authors: Chitralekha Ngangbam, Aniruddha Mondal, Naorem Khelchand Singh

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Aluminium (Al) doped In2O3 (Indium Oxide) nanocolumn array was synthesized by glancing angle deposition (GLAD) technique on Si (n-type) substrate for photodetector application. The sample was characterized by scanning electron microscopy (SEM). The average diameter of the nanocolumn was calculated from the top view of the SEM image and found to be ∼80 nm. The length of the nanocolumn (~500 nm) was calculated from cross sectional SEM image and it shows that the nanocolumns are perpendicular to the substrate. The EDX analysis confirmed the presence of Al (Aluminium), In (Indium), O (Oxygen) elements in the samples. The XRD patterns of the Al-doped In2O3 nanocolumn show the presence of different phases of the Al doped In2O3 nanocolumn i.e. (222) and (622). Three different peaks were observed from the PL analysis of Al doped In2O3 nanocolumn at 365 nm, 415 nm and 435 nm respectively. The peak at PL emission at 365 nm can be attributed to the near band gap transition of In2O3 whereas the peaks at 415 nm and 435 nm can be attributed to the trap state emissions due to oxygen vacancies and oxygen–indium vacancy centre in Al doped In2O3 nanocolumn. The current-voltage (I–V) characteristics of the Al doped In2O3 nanocolumn based detector was measured through the Au Schottky contact. The devices were then examined under the halogen light (20 W) illumination for photocurrent measurement. The Al-doped In2O3 nanocolumn based optical detector showed high conductivity and low turn on voltage at 0.69 V under white light illumination. A maximum photoresponsivity of 82 A/W at 380 nm was observed for the device. The device shows a high internal gain of ~267 at UV region (380 nm) and ∼127 at visible region (760 nm). Also the rise time and fall time for the device at 650 nm is 0.15 and 0.16 sec respectively which makes it suitable for fast response detector.

Keywords: glancing angle deposition, nanocolumn, semiconductor, photodetector, indium oxide

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Authors: Nuruddeen Abubakar Adamu

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Background: Global health nursing describes health-related work across borders and focuses more on the differences between the nurses’ role between countries and identified why nursing care in particular country differs from another. It also helps in analyzing the health issues and concerns that transcend national borders class, race, ethnicity and culture. The primary objective of this study is to introduce the concept of global health nursing. And the article also argues for the need for global health nursing. Methods This review assesses available evidence, both published and unpublished, on issues relating to the global health nursing and the nurse's role in global health. The review is qualitative based. Results: Globalization, modern technologies, travel, migration and changes in diseases trend globally has made the nursing role to become more diverse and less traditional. These issues change the nurse’s role in the healthcare industry to become enormous and very challenging. This article considers response to issues of emerging global health nursing concept, challenges, purposes, global health nursing activities in both developed and developing countries and the nurse's role globally in maternal-newborn health; preparedness for advocacy in global health within a framework of social justice, equity; and health system strengthening globally. Conclusion: Global health nursing goes beyond the intervention to care for a patient with a particular health problem but, however health is interconnected to political, economic and social context and therefore this explains the need of a multi-professional and multi-sectoral approach to achieve the goal of global health and the need for global health nursing. Global health equity can be promoted and if the profile of nursing and nurses will be raised and enable nurses to be aware of global health issues so as to enable them to work to their full maximum potential, to attain greater health outcome and wellness.

Keywords: global health nursing, double burden of diseases, globalization, health equity

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Authors: Ahmed Ghachem, Johann Colomba, Denis Prud'homme, Martin Brochu

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Background: Inactive obese postmenopausal women, are at greater risk for metabolic complications. On the other hand, high levels of cardiorespiratory fitness (CRF) are associated with a lower risk of metabolic complications. Objective: To compare inactive obese postmenopausal women displaying ‘lower’ vs ‘higher’ levels of CRF for body composition, metabolic profile, inflammatory profile and measures of energy expenditure. Methods: 132 women (age: 57.6 ± 4.8 yrs; BMI: 32.3 ± 4.6 kg/m2; Peak VO2: 17.81 ± 3.02 ml O2•kg-1•min-1) were studied. They were first divided into tertiles based on their CRF. Then, women in the first (< 16.51 ml O2•min-1•kg-1) and second tertiles (16.51 to 19.22 ml O2•min-1•kg-1) were combined (N= 88), and compared with those in the third tertile (> 19.22 ml O2•min-1•kg-1) (N= 44). Variables of interest were: Peak VO2 (stationary bike), body composition (DXA), body fat distribution (CT scan), glucose homeostasis (fasting state and euglycemic/ hyperinsulinemic clamp), fasting lipids, resting blood pressure, inflammatory profile and energy expenditure (DLW). Results: Both CRF groups (lower= 16.0 ± 2.0 ml O2•kg-1•min-1 vs higher= 21.2 ± 1.7 ml O2•kg-1•min-1; p < 0.001) were similar for age. Significant differences were observed between groups for body composition; with lower values for body weight, BMI, fat mass and visceral fat in women with higher CRF (p between 0.001 and 0.005). Also, women with higher CRF had lower values for fasting insulin (13.4 ± 4.5 vs 15.6 ± 6.6 μU/ml; p = 0.03) and CRP levels (2.31 ± 1.97 vs 3.83 ± 3.24 mg/liter; p = 0.001); and higher values for glucose disposal (6.71 ± 1.78 vs 5.92 ± 1.67 mg/kg/min; p = 0.01). However, these differences were no longer significant after controlling for visceral adipose tissue accumulations. Finally, no significant difference was observed between groups for the other variables of interest. Conclusion: Our results suggest that, among inactive overweight/obese postmenopausal women, those with higher CRF levels have a better metabolic profile; which is caused by lower visceral fat accumulations.

Keywords: cardiorespiratory fitness, metabolic profile, menopause, obesity

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Authors: Tukur Daiyabu Abdulkadir, Wan Ishak Wan Ismail, Muhammad Saufi Mohd Kassim

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Seed singulation and accuracy in seed spacing are the major challenges associated with the adoption of mechanical seeder for system of rice intensification. In this research the metering system of a pneumatic planter was modified and automated for increase precision to meet the demand of system of rice intensification SRI. The chain and sprocket mechanism of a conventional vacuum planter were now replaced with an electro mechanical system made up of a set of servo motors, limit switch, micro controller and a wheel divided into 10 equal angles. The circumference of the planter wheel was determined based on which seed spacing was computed and mapped to the angles of the metering wheel. A program was then written and uploaded to arduino micro controller and it automatically turns the seed plates for seeding upon covering the required distance. The servo motor was calibrated with the aid of labVIEW. The machine was then calibrated using a grease belt and varying the servo rpm through voltage variation between 37 rpm to 47 rpm until an optimum value of 40 rpm was obtained with a forward speed of 5 kilometers per hour. A pressure of 1.5 kpa was found to be optimum under which no skip or double was recorded. Precision in spacing (coefficient of variation), miss index, multiple index, doubles and skips were investigated. No skip or double was recorded both at laboratory and field levels. The operational parameters under consideration were both evaluated at laboratory and field. Even though there was little variation between the laboratory and field values of precision in spacing, multiple index and miss index, the different is not significant as both laboratory and field values fall within the acceptable range.

Keywords: automation, calibration, pneumatic seed planter, system of rice intensification

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Authors: Adeshina Fadeyibi

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Application of pure thermoplastic film in food packaging is greatly limited because of its poor service performance, often enhanced by the addition of organic or inorganic particles in the range of 1–100 nm. Thus, this study was conducted to develop cassava starch zinc-nanocomposite films for applications in food packaging. Three blending ratios of 1000 g cassava starch, 45–55 % (w/w) glycerol and 0–2 % (w/w) zinc nanoparticles were formulated, mixed and mechanically homogenized to form the nanocomposite. Thermoplastic were prepared, from a dispersed mixture of 24 g of the nanocomposite and 600 ml of distilled water, and heated to 90oC for 30 minutes. Plastic molds of 350 ×180 mm dimension and 8, 10 and 12 mm depths were used for film casting and drying at 60oC and 80 % RH for 24 hour. The average thicknesses of the dried films were found to be 15, 16 and 17 µm. The films were characterized based on their barrier, thermal, mechanical and structural properties. The results show that the oxygen and water vapor barrier properties increased with glycerol concentration and decreased with thickness; but the full width at half maximum (FWHM) and d- spacing increased with thickness. The higher degree of d- spacing obtained is a consequence of higher polymer intercalation and exfoliation. Also, only 2 % weight degradation was observed when the films were exposed to temperature between 30–60oC; indicating that they are thermally stable and can be used for packaging applications in the tropics. The mechanical properties of the film were higher than that of the pure thermoplastic but comparable with the LDPE films. The information on the characterized attributes and optimization of the cassava starch zinc-nanocomposite films justifies their alternative application to pure thermoplastic and conventional films for food packaging.

Keywords: synthesis, characterization, casaava Starch, nanocomposite film, packaging

Procedia PDF Downloads 113

Authors: A. Kherraf, M. Bouziane, A. Drighil, L. Azzouzi, R. Habbal

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Objective: Myxomas are rare heart tumors most commonly found in the left atrium. The purpose of this observation is to report a rare case of myxoma of the right atrium revealed by pulmonary embolism. Observation: A 34-year-old patient with no history presented to the emergency room with sudden onset dyspnea. Clinical examination showed arterial pressure at 110/70mmHg, tachycardia at 110bpm, and 90% oxygen saturation. The ECG enrolled in incomplete right bundle branch block. The radio-thorax was normal. Echocardiography revealed the presence of a large homogeneous intra-OD mass, contiguous to the inter-atrial septum, prolapsing through the tricuspid valve, and causing mild tricuspid insufficiency, with dilation of the right ventricle and retained systolic function with PAPs estimated at 45mmHg. A chest scan was performed, revealing the presence of right segmental pulmonary embolism. The patient was put under anticoagulant and underwent surgical resection of the mass; its pathological examination concluded to a myxoma. The post-operative consequences were simple, without recurrence of the mass after one year follow-up. Discussion: Myxomas represent 50% of heart tumors. Most often, they originate in the left atrium, and more rarely in the right atrium or the ventricles. Myxoma of the right atrium can be responsible for life-threatening pulmonary embolism. The most predictive factor for embolization remains the morphology of the myxomas; papillary or villous myxomas are the most friable. Surgery is the standard treatment, with regular postoperative follow-up to detect recurrence. Conclusion: Myxomas of the right atrium are a rare location for these tumors. Pulmonary embolism is the main complication and should routinely involve careful study of the right chambers on echocardiography.

Keywords: pulmonary embolism, myxoma, right atrium, heart tumors

Procedia PDF Downloads 140

Authors: Rita Yuniatun, Dewi Fadlilah Firdausi, Anida Hanifah, Putrisuvi Nurjannah Zalqis, Erza Nur Afrilia, Akrima Fajrin Nurimani, Andrew Luis Krishna

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Manganese (Mn) is one of the potential contaminants minerals geothermal water. Preliminary studies conducted in Ketenger village, the nearest village with Baturaden hot spring, showed that the concentration of Mn in water supply has exceeded the reference value. Mineral contamination problem in Ketenger village is not only Mn, but also other potential geothermal minerals, such as chromium (Cr), iron (Fe), sulfide (S2-), nickel (Ni), cobalt (Co), and zinc (Zn). It becomes a concern because generally the residents still use ground water as the water source for their daily needs, including drinking and cooking. Therefore, this study aimed to determine the distribution of mineral contamination in drinking water and food and to estimate the health risks possibility from the exposure. Four minerals (Mn, Fe, S2-, and Cr6+) were analyzed in drinking water, carbohydrate sources, vegetables, fishes, and fruits. The test results indicate that Mn concentration in drinking water is 0.35 mg/L, has exceeded the maximum contaminant level (MCL) according to the US EPA (MCL = 0.005 mg/L), whereas other minerals still comply with the standards. In addition, we found that the average of Mn concentration in the carbohydrate sources is quite high (1.87 mg/Kg). Measurement results in Chronic Daily Intake (CDI) and the Risk Quotient (RQ) found that exposure to manganese and other geothermal minerals in drinking water and food are safe from the non-carcinogenic effects in each age group (RQ<1). So, geothermal mineral concentrations in drinking water and food has no effect on non-carcinogenic risk in Ketenger’s residents because of CDI is also influenced by other parameters such as the duration of exposure and the rate of consumption. However, it was found that intake of essential minerals (Mn and Fe) are deficient in every age group. So that, the addition of Mn and Fe intake is recommended.

Keywords: CDI, contaminant, geothermal minerals, manganese, RQ

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Authors: Guram Adamashvili

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Surface plasmon polariton is a surface optical wave which undergoes a strong enhancement and spatial confinement of its wave amplitude near an interface of two-dimensional layered structures. Phosphorene (single-layer black phosphorus) and other two-dimensional anisotropic phosphorene-like materials are recognized as promising materials for potential future applications of surface plasmon polariton. A theory of an optical breather of self-induced transparency for surface plasmon polariton propagating in monolayer or few-layer phosphorene is developed. A theory of an optical soliton of self-induced transparency for surface plasmon polariton propagating in monolayer or few-layer phosphorene have been investigated earlier Starting from the optical nonlinear wave equation for surface TM-modes interacting with a two-dimensional layer of atomic systems or semiconductor quantum dots and a phosphorene monolayer (or other two-dimensional anisotropic material), we have obtained the evolution equations for the electric field of the breather. In this case, one finds that the evolution of these pulses become described by the damped Bloch-Maxwell equations. For surface plasmon polariton fields, breathers are found to occur. Explicit relations of the dependence of breathers on the local media, phosphorene anisotropic conductivity, transition layer properties and transverse structures of the SPP, are obtained and will be given. It is shown that the phosphorene conductivity reduces exponentially the amplitude of the surface breather of SIT in the process of propagation. The direction of propagation corresponding to the maximum and minimum damping of the amplitude are assigned along the armchair and zigzag directions of black phosphorus nano-film, respectively. The most rapid damping of the intensity occurs when the polarization of breather is along the armchair direction.

Keywords: breathers, nonlinear waves, solitons, surface plasmon polaritons

Procedia PDF Downloads 142

Authors: Adilah Shariff, Nur Syairah Mohamad Aziz, Norsyahidah Md Saleh, Nur Syuhada Izzati Ruzali

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The first objective of this study is to investigate the suitability of coconut frond (CF) and coconut husk (CH) as feedstocks using a laboratory-scale slow pyrolysis experimental setup. The second objective is to investigate the effect of pyrolysis temperature on the biochar yield. The properties of CF and CH feedstocks were compared. The properties of the CF and CH feedstocks were investigated using proximate and elemental analysis, lignocellulosic determination, and also thermogravimetric analysis (TGA). The CF and CH feedstocks were pyrolysed at 300, 400, 500, 600 and 700 °C for 2 hours at 10 °C/min heating rate. The proximate analysis showed that CF feedstock has 89.96 mf wt% volatile matter, 4.67 mf wt% ash content and 5.37 mf wt% fixed carbon. The lignocelluloses analysis showed that CF feedstock contained 21.46% lignin, 39.05% cellulose and 22.49% hemicelluloses. The CH feedstock contained 84.13 mf wt% volatile matter, 0.33 mf wt% ash content, 15.54 mf wt% fixed carbon, 28.22% lignin, 33.61% cellulose and 22.03% hemicelluloses. Carbon and oxygen are the major component of the CF and CH feedstock compositions. Both of CF and CH feedstocks contained very low percentage of sulfur, 0.77% and 0.33%, respectively. TGA analysis indicated that coconut wastes are easily degraded. It may be due to their high volatile content. Between the temperature ranges of 300 and 800 °C, the TGA curves showed that the weight percentage of CF feedstock is lower than CH feedstock by 0.62%-5.88%. From the D TGA curves, most of the weight loss occurred between 210 and 400 °C for both feedstocks. The maximum weight loss for both CF and CH are 0.0074 wt%/min and 0.0061 wt%/min, respectively, which occurred at 324.5 °C. The yield percentage of both CF and CH biochars decreased significantly as the pyrolysis temperature was increased. For CF biochar, the yield decreased from 49.40 wt% to 28.12 wt% as the temperature increased from 300 to 700 °C. The yield for CH biochars also decreased from 52.18 wt% to 28.72 wt%. The findings of this study indicated that both CF and CH are suitable feedstock for slow pyrolysis of biochar.

Keywords: biochar, biomass, coconut wastes, slow pyrolysis

Procedia PDF Downloads 206

Authors: Dorina Rusu, Emil Ghiocel Ioanid, Marta Ursescu, Ana Maria Vlad, Mihaela Popescu

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During the last decades the cold plasma discharges made the subject of numerous studies concerning the applications in the cultural heritage field, especially concentrated on ecological and non-invasive aspect of these conservation procedures. The conservation treatment using cold plasma is based, on the one hand, on the well-known property of plasma discharges to inactivate the contaminant biological species and, on the other hand, on the surface cleaning effect. Moreover the plasma discharge produces the functionalization of the treated surface, allowing subsequent deposition of protective layers. The paper presents the behavior of printing inks on historical documents treated in cold RF plasma. Two types of printing inks were studied, namely red and black ink, used on a religious book published in 19 century. SEM-EDX analysis results in the identification of the two inks as carbon black ink (C presence in the EDX spectrum) and cinnabar based red ink (Hg and S lines in the spectrum), result confirmed by XRF analysis. The experiments have been performed on paper samples written with laboratory- made inks, of similar composition with the inks identified on historical documents. The samples were subjected to RF plasma discharge, operating in nitrogen gaseous medium, at 1.2 MHz frequency and low-pressure (0.5 mbar), performed in a self-designed equipment for the application of conservation treatments on naturally aged paper supports. The impact of plasma discharge on the inks has been evaluated by SEM, XRD and color analysis. The color analysis revealed a slight discoloration of cinnabar ink on the historical document. SEM and XRD analyses have been carried out in an attempt to elucidate the process responsable for color modification.

Keywords: RF plasma, printing inks, historical documents, surface cleaning effect

Procedia PDF Downloads 432

Authors: Ramesh Kumar Behera, Md. Izhar Hassan

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Accident investigation and analysis are useful to identify deficiencies in plant, process, and management practices and formulate preventive strategies for injury elimination. In India and other parts of the world, industrial accidents are investigated to know the causes and also to fulfill legal compliances. However, findings of investigation are seldom used appropriately to strengthen Occupational Safety and Health (OSH) in expected lines. The mineral rich state of Odisha in eastern coast of India; known as a hub for Iron and Steel industries, witnessed frequent accidents during 2005-2009. This article based on study of 982 fatal ‘factory-accidents’ occurred in Odisha during the period 2001-2016, discusses the ‘turnaround-story’ resulting in reduction of fatal accident from 122 in 2009 to 45 in 2016. This paper examines various factors causing incidents; accident pattern in steel and chemical sector; role of climate and harsh weather conditions on accident causation. Software such as R, SQL, MS-Excel and Tableau were used for analysis of data. It is found that maximum fatality is caused due to ‘fall from height’ (24%); steel industries are relatively more accident prone; harsh weather conditions of summer increase chances of accident by 20%. Further, the study suggests that enforcement of partial work-restriction around lunch time during peak summer, screening and training of employees reduce accidents due to fall from height. The study indicates that learning from accident investigation and analysis can be used as a method to reduce work related accidents in the journey towards ‘Vision Zero’.

Keywords: accident investigation and analysis, fatal accidents in India, fall from height, vision zero

Procedia PDF Downloads 150

Authors: Gyati Shilakari Asthana, Abhay Asthana, Dharm Veer Kohli, Suresh Prasad Vyas

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Purpose: The therapeutic potential of oligonucleotide (ODN) is primarily dependent upon its safe and efficient delivery to specific cells overcoming degradation and maximizing cellular uptake in vivo. The present study is focused to design low molecular weight chitosan nanoconstructs to meet the requirements of safe and effectual delivery of ODNs. LMW-chitosan is a biodegradable, water soluble, biocompatible polymer and is useful as a non-viral vector for gene delivery due to its better stability in water. Methods: LMW chitosan ODN nanoparticles (CHODN NPs) were formulated by self-assembled method using various N/P ratios (moles ratio of amine groups of CH to phosphate moieties of ODNs; 0.5:1, 1:1, 3:1, 5:1, and 7:1) of CH to ODN. The developed CHODN NPs were evaluated with respect to gel retardation assay, particle size, zeta potential and cytotoxicity and transfection efficiency. Results: Complete complexation of CH/ODN was achieved at the charge ratio of 0.5:1 or above and CHODN NPs displayed resistance against DNase I. On increasing the N/P ratio of CH/ODN, the particle size of the NPs decreased whereas zeta potential (ZV) value increased. No significant toxicity was observed at all CH concentrations. The transfection efficiency was increased on increasing N/P ratio from 1:1 to 3:1, whereas it was decreased with further increment in N/P ratio upto 7:1. Maximum transfection of CHODN NPs with both the cell lines (Raw 267.4 cells and Hela cells) was achieved at N/P ratio of 3:1. The results suggest that transfection efficiency of CHODN NPs is dependent on N/P ratio. Conclusion: Thus the present study states that LMW chitosan nanoparticulate carriers would be acceptable choice to improve transfection efficiency in vitro as well as in vivo delivery of oligonucleotide.

Keywords: LMW-chitosan, chitosan nanoparticles, biocompatibility, cytotoxicity study, transfection efficiency, oligonucleotide

Procedia PDF Downloads 846

Authors: Thidarat Imyen, Paisan Kongkachuichay

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Cu-Zn/core-shell Al-MCM-41 catalyst with various copper species, prepared by a combination of three methods—substitution, ion-exchange, and impregnation, was studied for the selective catalytic reduction (SCR) of NO with NH3 at 300 °C for 150 min. In order to investigate the effects of Zn introduction on the nature of the catalyst, Cu/core-shell Al-MCM-41 and Zn/core-shell Al-MCM-41 catalysts were also studied. The roles of Zn promoter in the acidity and the NOx adsorption properties of the catalysts were investigated by in situ Fourier transform infrared spectroscopy (FTIR) of NH3 and NOx adsorption, and temperature-programmed desorption (TPD) of NH3 and NOx. The results demonstrated that the acidity of the catalyst was enhanced by the Zn introduction, as exchanged Zn(II) cations loosely bonded with Al-O-Si framework could create Brønsted acid sites by interacting with OH groups. Moreover, Zn species also provided the additional sites for NO adsorption in the form of nitrite (NO2–) and nitrate (NO3–) species, which are the key intermediates for SCR reaction. In addition, the effect of Zn on the nature of copper was studied by in situ FTIR of CO adsorption and in situ X-ray adsorption near edge structure (XANES). It was found that Zn species hindered the reduction of Cu(II) to Cu(0), resulting in higher Cu(I) species in the Zn promoted catalyst. The Cu-Zn/core-shell Al-MCM-41 exhibited higher catalytic activity compared with that of the Cu/core-shell Al-MCM-41 for the whole reaction time, as it possesses the highest amount of Cu(I) sites, which are responsible for SCR catalytic activity. The Cu-Zn/core-shell Al-MCM-41 catalyst also reached the maximum NO conversion of 100% with the average NO conversion of 76 %. The catalytic performance of the catalyst was further improved by using Zn promoter in the form of ZnO instead of reduced Zn species. The Cu-ZnO/core-shell Al-MCM-41 catalyst showed better catalytic performance with longer working reaction time, and achieved the average NO conversion of 81%.

Keywords: Al-MCM-41, copper, nitrogen oxide, selective catalytic reduction, zinc

Procedia PDF Downloads 297