Search results for: angular distribution for Cr deposition rate
11005 Wear Assessment of SS316l-Al2O3 Composites for Heavy Wear Applications
Authors: Catherine Kuforiji, Michel Nganbe
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The abrasive wear of composite materials is a major challenge in highly demanding wear applications. Therefore, this study focuses on fabricating, testing and assessing the properties of 50wt% SS316L stainless steel–50wt% Al2O3 particle composites. Composite samples were fabricated using the powder metallurgy route. The effects of the powder metallurgy processing parameters and hard particle reinforcement were studied. The microstructure, density, hardness and toughness were characterized. The wear behaviour was studied using pin-on-disc testing under dry sliding conditions. The highest hardness of 1085.2 HV, the highest theoretical density of 94.7% and the lowest wear rate of 0.00397 mm3/m were obtained at a milling speed of 720 rpm, a compaction pressure of 794.4 MPa and sintering at 1400 °C in an argon atmosphere. Compared to commercial SS316 and fabricated SS316L, the composites had 7.4 times and 11 times lower wear rate, respectively. However, the commercial 90WC-10Co showed 2.2 times lower wear rate compared to the fabricated SS316L-Al2O3 composites primarily due to the higher ceramic content of 90 wt.% in the reference WC-Co. However, eliminating the relatively high porosity of about 5 vol% using processes such as HIP and hot pressing can be expected to lead to further substantial improvements of the composites wear resistance.Keywords: SS316L, Al2O3, powder metallurgy, wear characterization
Procedia PDF Downloads 30411004 Carbon Nanofibers as the Favorite Conducting Additive for Mn₃O₄ Catalysts for Oxygen Reactions in Rechargeable Zinc-Air Battery
Authors: Augustus K. Lebechi, Kenneth I. Ozoemena
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Rechargeable zinc-air batteries (RZABs) have been described as one of the most viable next-generation ‘beyond-the-lithium-ion’ battery technologies with great potential for renewable energy storage. It is safe, with a high specific energy density (1086 Wh/kg), environmentally benign, and low-cost, especially in resource-limited African countries. For widespread commercialization, the sluggish oxygen reaction kinetics pose a major challenge that impedes the reversibility of the system. Hence, there is a need for low-cost and highly active bifunctional electrocatalysts. Manganese oxide catalysts on carbon conducting additives remain the best couple for the realization of such low-cost RZABs. In this work, hausmannite Mn₃O₄ nanoparticles were synthesized through the annealing method from commercial electrolytic manganese dioxide (EMD), multi-walled carbon nanotubes (MWCNTs) were synthesized via the chemical vapor deposition (CVD) method and carbon nanofibers (CNFs) were synthesized via the electrospinning process with subsequent carbonization. Both Mn₃O₄ catalysts and the carbon conducting additives (MWCNT and CNF) were thoroughly characterized using X-ray powder diffraction spectroscopy (XRD), scanning electron microscopy (SEM), thermogravimetry analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Composite electrocatalysts (Mn₃O₄/CNT and Mn₃O₄/CNF) were investigated for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in an alkaline medium. Using the established electrocatalytic modalities for evaluating the electrocatalytic performance of materials (including double layer, electrochemical active surface area, roughness factor, specific current density, and catalytic stability), CNFs proved to be the most efficient conducting additive material for the Mn₃O₄ catalyst. From the DFT calculations, the higher performance of the CNFs over the MWCNTs is related to the ability of the CNFs to allow for a more favorable distribution of the d-electrons of the manganese (Mn) and enhanced synergistic effect with Mn₃O₄ for weaker adsorption energies of the oxygen intermediates (O*, OH* and OOH*). In a proof-of-concept, Mn₃O₄/CNF was investigated as the air cathode for rechargeable zinc-air battery (RZAB) in a micro-3D-printed cell configuration. The RZAB showed good performance in terms of open circuit voltage (1.77 V), maximum power density (177.5 mW cm-2), areal-discharge energy and cycling stability comparable to Pt/C (20 wt%) + IrO2. The findings here provide fresh physicochemical perspectives on the future design and utility of CNFs for developing manganese-based RZABs.Keywords: bifunctional electrocatalyst, oxygen evolution reaction, oxygen reduction reactions, rechargeable zinc-air batteries.
Procedia PDF Downloads 6411003 Finite Eigenstrains in Nonlinear Elastic Solid Wedges
Authors: Ashkan Golgoon, Souhayl Sadik, Arash Yavari
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Eigenstrains in nonlinear solids are created due to anelastic effects such as non-uniform temperature distributions, growth, remodeling, and defects. Eigenstrains understanding is indispensable, as they can generate residual stresses and strongly affect the overall response of solids. Here, we study the residual stress and deformation fields of an incompressible isotropic infinite wedge with a circumferentially-symmetric distribution of finite eigenstrains. We construct a material manifold, whose Riemannian metric explicitly depends on the eigenstrain distribution, thereby we turn the problem into a classical nonlinear elasticity problem, where we find an embedding of the Riemannian material manifold into the ambient Euclidean space. In particular, we find exact solutions for the residual stress and deformation fields of a neo-Hookean wedge having a symmetric inclusion with finite radial and circumferential eigenstrains. Moreover, we numerically solve a similar problem when a symmetric Mooney-Rivlin inhomogeneity with finite eigenstrains is placed in a neo-Hookean wedge. Generalization of the eigenstrain problem to other geometries are also discussed.Keywords: finite eigenstrains, geometric mechanics, inclusion, inhomogeneity, nonlinear elasticity
Procedia PDF Downloads 25511002 Alternative Ways to Measure Impacts of Dam Closure to the Structure of Fish Communities of a Neotropical River
Authors: Ana Carolina Lima, Carlos Sérgio Agostinho, Amadeu M. V. M. Soares, Kieran A. Monaghan
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Neotropical freshwaters host some of the most biodiverse ecosystems in the world and are among the most threatened by habitat alterations. The high number of species and lack of basic ecological knowledge provides a major obstacle to understanding the effects of environmental change. We assessed the impact of dam closure on the fish communities of a neotropical river by applying simple descriptions of community organizations: Species Abundance Distribution (SAD) and Abundance Biomass Comparison (ABC) curves. Fish data were collected during three distinct time periods (one year before, one year after and five years after closure), at eight sites located downstream of the dam, in the reservoir and reservoir transition zone and upstream of the regulated flow. Dam closure was associated with changes in the structural and functional organization of fish communities at all sites. Species richness tended to increase immediately after dam closure while evenness decreased. Changes in taxonomic structure were accompanied by a change in the distribution of biomass with the proportionate contribution by smaller individuals significantly increased relative to larger individuals. Five years on, richness had fallen to below pre-closure levels at all sites, while the comparative stability of the transformed habitats was reflected by biomass-abundance distribution patterns that approximated pre-disturbance ratios. Despite initial generality, respective sites demonstrated distinct ecological responses that were related to the environmental characteristics of their transformed habitats. This simplistic analysis provides a sensitive and informative assessment of ecological conditions that highlights the impact to ecosystem process and ecological networks and has particular value in regions where detailed ecological knowledge precludes the application of traditional bioassessment methods.Keywords: ABC curves, SADs, biodiversity, damming, tropical fish
Procedia PDF Downloads 38811001 Residual Dipolar Couplings in NMR Spectroscopy Using Lanthanide Tags
Authors: Elias Akoury
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Nuclear Magnetic Resonance (NMR) spectroscopy is an indispensable technique used in structure determination of small and macromolecules to study their physical properties, elucidation of characteristic interactions, dynamics and thermodynamic processes. Quantum mechanics defines the theoretical description of NMR spectroscopy and treatment of the dynamics of nuclear spin systems. The phenomenon of residual dipolar coupling (RDCs) has become a routine tool for accurate structure determination by providing global orientation information of magnetic dipole-dipole interaction vectors within a common reference frame. This offers accessibility of distance-independent angular information and insights to local relaxation. The measurement of RDCs requires an anisotropic orientation medium for the molecules to partially align along the magnetic field. This can be achieved by introduction of liquid crystals or attaching a paramagnetic center. Although anisotropic paramagnetic tags continue to mark achievements in the biomolecular NMR of large proteins, its application in small organic molecules remains unspread. Here, we propose a strategy for the synthesis of a lanthanide tag and the measurement of RDCs in organic molecules using paramagnetic lanthanide complexes.Keywords: lanthanide tags, NMR spectroscopy, residual dipolar coupling, quantum mechanics of spin dynamics
Procedia PDF Downloads 18811000 Comparison of Electrical Parameters of Oil-Immersed and Dry-Type Transformer Using Finite Element Method
Authors: U. Amin, A. Talib, S. A. Qureshi, M. J. Hossain, G. Ahmad
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The choice evaluation between oil-immersed and dry-type transformers is often controlled by cost, location, and application. This paper compares the electrical performance of liquid- filled and dry-type transformers, which will assist the customer to choose the right and efficient ones for particular applications. An accurate assessment of the time-average flux density, electric field intensity and voltage distribution in an oil-insulated and a dry-type transformer have been computed and investigated. The detailed transformer modeling and analysis has been carried out to determine electrical parameter distributions. The models of oil-immersed and dry-type transformers are developed and solved by using the finite element method (FEM) to compare the electrical parameters. The effects of non-uniform and non-coherent voltage gradient, flux density and electric field distribution on the power losses and insulation properties of transformers are studied in detail. The results show that, for the same voltage and kilo-volt-ampere (kVA) rating, oil-immersed transformers have better insulation properties and less hysteresis losses than the dry-type.Keywords: finite element method, flux density, transformer, voltage gradient
Procedia PDF Downloads 29210999 CFD Prediction of the Round Elbow Fitting Loss Coefficient
Authors: Ana Paula P. dos Santos, Claudia R. Andrade, Edson L. Zaparoli
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Pressure loss in ductworks is an important factor to be considered in design of engineering systems such as power-plants, refineries, HVAC systems to reduce energy costs. Ductwork can be composed by straight ducts and different types of fittings (elbows, transitions, converging and diverging tees and wyes). Duct fittings are significant sources of pressure loss in fluid distribution systems. Fitting losses can be even more significant than equipment components such as coils, filters, and dampers. At the present work, a conventional 90o round elbow under turbulent incompressible airflow is studied. Mass, momentum, and k-e turbulence model equations are solved employing the finite volume method. The SIMPLE algorithm is used for the pressure-velocity coupling. In order to validate the numerical tool, the elbow pressure loss coefficient is determined using the same conditions to compare with ASHRAE database. Furthermore, the effect of Reynolds number variation on the elbow pressure loss coefficient is investigated. These results can be useful to perform better preliminary design of air distribution ductworks in air conditioning systems.Keywords: duct fitting, pressure loss, elbow, thermodynamics
Procedia PDF Downloads 39110998 Structural and Optoelectronic Properties of Monovalent Cation Doping PbS Thin Films
Authors: Melissa Chavez Portillo, Hector Juarez Santiesteban, Mauricio Pacio Castillo, Oscar Portillo Moreno
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Nanocrystalline Li-doped PbS thin films have been deposited by chemical bath deposition technique. The goal of this work is to study the modification of the optoelectronic and structural properties of Lithium incorporation. The increase of Li doping in PbS thin films leads to an increase of band gap in the range of 1.4-2.3, consequently, quantum size effect becomes pronounced in the Li-doped PbS films, which lead to a significant enhancement in the optical band gap. Doping shows influence in the film growth and results in a reduction of crystallite size from 30 to 14 nm. The refractive index was calculated and a relationship with dielectric constant was investigated. The dc conductivities of Li-doped and undoped samples were measured in the temperature range 290-340K, the conductivity increase with increase of Lithium content in the PbS films.Keywords: doping, quantum confinement, optical band gap, PbS
Procedia PDF Downloads 38410997 Characterisation and in vitro Corrosion Resistance of Plasma Sprayed Hydroxyapatite and Hydroxyapatite: Silicon Oxide Coatings on 316L SS
Authors: Gurpreet Singh, Hazoor Singh, Buta Singh Sidhu
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In the current investigation plasma spray technique was used for depositing hydroxyapatite (HA) and HA – silicon oxide (SiO2) coatings on 316L SS substrate. In HA-SiO2 coating, 20 wt% SiO2 was mixed with HA. The feedstock and coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) analyses. The corrosion resistance of the uncoated, HA coated and HA + 20 wt% SiO2 coated 316L SS was investigated by electrochemical corrosion testing in simulated human body fluid (Ringer’s solution). The influence of SiO2 (20 wt%) on corrosion resistance was determined. After the corrosion testing, the samples were analyzed by XRD and SEM/EDX analyses. The addition of SiO2 reduces the crystallinity of the coating. The corrosion resistance of the 316L SS was found to increase after the deposition of the HA + 20 wt% SiO2 and HA coatings.Keywords: HA, SiO2, corrosion, Ringer’s solution, 316L SS
Procedia PDF Downloads 41910996 Amino Acid Coated Silver Nanoparticles: A Green Catalyst for Methylene Blue Reduction
Authors: Abhishek Chandra, Man Singh
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Highly stable and homogeneously dispersed amino acid coated silver nanoparticles (ANP) of ≈ 10 nm diameter, ranging from 420 to 430 nm are prepared on AgNO3 solution addition to gum of Azadirachta indica solution at 373.15 K. The amino acids were selected based on their polarity. The synthesized nanoparticles were characterized by UV-Vis, FTIR spectroscopy, HR-TEM, XRD, SEM and 1H-NMR. The coated nanoparticles were used as catalyst for the reduction of methylene blue dye in presence of Sn(II) in aqueous, anionic and cationic micellar media. The rate of reduction of dye was determined by measuring the absorbance at 660 nm, spectrophotometrically and followed the order: Kcationic > Kanionic > Kwater. After 12 min and in absence of the ANP, only 2%, 3% and 6% of the dye reduction was completed in aqueous, anionic and cationic micellar media respectively while, in presence of ANP coated by polar neutral amino acid with non-polar -R group, the reduction completed to 84%, 95% and 98% respectively. The ANP coated with polar neutral amino acid having non-polar -R group, increased the rate of reduction of the dye by 94, 3205 and 6370 folds in aqueous, anionic and cationic micellar media respectively. Also, the rate of reduction of the dye increased by three folds when the micellar media was changed from anionic to cationic when the ANP is coated by a polar neutral amino acid having a non-polar -R group.Keywords: silver nanoparticle, surfactant, methylene blue, amino acid
Procedia PDF Downloads 35910995 Predicting Mixing Patterns of Overflows from a Square Manhole
Authors: Modupe O. Jimoh
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During manhole overflows, its contents pollute the immediate environment. Understanding the pollutant transfer characteristics between manhole’s incoming sewer and the overflow is therefore of great importance. A square manhole with sides 388 mm by 388 mm and height 700 mm with an overflow facility was used in the laboratory to carry out overflow concentration measurements. Two scenarios were investigated using three flow rates. The first scenario corresponded to when the exit of the pipe becomes blocked and the only exit for the flow is the manhole. The second scenario is when there is an overflow in combination with a pipe exit. The temporal concentration measurements showed that the peak concentration of pollutants in the flow was attenuated between the inlet and the overflow. A deconvolution software was used to predict the Residence time distribution (RTD) and consequently the Cumulative Residence time distribution (CRTD). The CRTDs suggest that complete mixing is occurring between the pipe inlet and the overflow, like what is obtained in a low surcharged manhole. The results also suggest that an instantaneous stirred tank reactor model can describe the mixing characteristics.Keywords: CRTDs, instantaneous stirred tank reactor model, overflow, square manholes, surcharge, temporal concentration profiles
Procedia PDF Downloads 14410994 A Comparative Study on Electrical Characteristics of Au/n-SiC structure, with and Without Zn-Doped PVA Interfacial Layer at Room Temperature
Authors: M. H. Aldahrob, A. Kokce, S. Altindal, H. E. Lapa
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In order to obtain the detailed information about the effect of (Zn-doped PVA) interfacial layer, surface states (Nss) and series resistance (Rs) on electrical characteristics, both Au/n- type 4H-SiC (MS) with and without (Zn doped PVA) interfacial layer were fabricated to compare. The main electrical parameters of them were investigated using forward and reverse bias current-voltage (I-V), capacitance-voltage (C-V) and conductance –voltage (G/W –V) measurements were performed at room temperature. Experimental results show that the value of ideality factor (n), zero –bias barrier height (ΦBo), Rs, rectifier rate (RR=IF/IR) and the density of Nss are strong functions interfacial layer and applied bias voltage. The energy distribution profile of Nss was obtained from forward bias I-V data by taking into account voltage dependent effective BH (ΦBo) and ideality factor (n(V)). Voltage dependent profile of Rs was also obtained both by using Ohm’s law and Nicollian and Brew methods. The other main diode parameters such as the concentration of doping donor atom (ND), Fermi energy level (EF).BH (ΦBo), depletion layer with (WD) were obtained by using the intercept and slope of the reverse bias C-2 vs V plots. It was found that (Zn-doped PVA) interfacial layer lead to a quite decrease in the values Nss, Rs and leakage current and increase in shunt resistance (Rsh) and RR. Therefore, we can say that the use of thin (Zn-doped PVA) interfacial layer can quite improved the performance of MS structure.Keywords: interfacial polymer layer, thickness dependence, electric and dielectric properties, series resistance, interface state
Procedia PDF Downloads 24810993 Analysis of the Unreliable M/G/1 Retrial Queue with Impatient Customers and Server Vacation
Authors: Fazia Rahmoune, Sofiane Ziani
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Retrial queueing systems have been extensively used to stochastically model many problems arising in computer networks, telecommunication, telephone systems, among others. In this work, we consider a $M/G/1$ retrial queue with an unreliable server with random vacations and two types of primary customers, persistent and impatient. This model involves the unreliability of the server, which can be subject to physical breakdowns and takes into account the correctives maintenances for restoring the service when a failure occurs. On the other hand, we consider random vacations, which can model the preventives maintenances for improving system performances and preventing breakdowns. We give the necessary and sufficient stability condition of the system. Then, we obtain the joint probability distribution of the server state and the number of customers in orbit and derive the more useful performance measures analytically. Moreover, we also analyze the busy period of the system. Finally, we derive the stability condition and the generating function of the stationary distribution of the number of customers in the system when there is no vacations and impatient customers, and when there is no vacations, server failures and impatient customers.Keywords: modeling, retrial queue, unreliable server, vacation, stochastic analysis
Procedia PDF Downloads 18710992 Influence of Radio Frequency Identification Technology at Cost of Supply Chain as a Driver for the Generation of Competitive Advantage
Authors: Mona Baniahmadi, Saied Haghanifar
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Radio Frequency Identification (RFID) is regarded as a promising technology for the optimization of supply chain processes since it improves manufacturing and retail operations from forecasting demand for planning, managing inventory, and distribution. This study precisely aims at learning to know the RFID technology and at explaining how it can concretely be used for supply chain management and how it can help improving it in the case of Hejrat Company which is located in Iran and works on the distribution of medical drugs and cosmetics. This study uses some statistical analysis to calculate the expected benefits of an integrated RFID system on supply chain obtained through competitive advantages increases with decreasing cost factor. The study investigates how the cost of storage process, labor cost, the cost of missing goods, inventory management optimization, on-time delivery, order cost, lost sales and supply process optimization affect the performance of the integrated RFID supply chain regarding cost factors and provides a competitive advantage.Keywords: cost, competitive advantage, radio frequency identification, supply chain
Procedia PDF Downloads 27710991 Peak Data Rate Enhancement Using Switched Micro-Macro Diversity in Cellular Multiple-Input-Multiple-Output Systems
Authors: Jihad S. Daba, J. P. Dubois, Yvette Antar
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With the exponential growth of cellular users, a new generation of cellular networks is needed to enhance the required peak data rates. The co-channel interference between neighboring base stations inhibits peak data rate increase. To overcome this interference, multi-cell cooperation known as coordinated multipoint transmission is proposed. Such a solution makes use of multiple-input-multiple-output (MIMO) systems under two different structures: Micro- and macro-diversity. In this paper, we study the capacity and bit error rate in cellular networks using MIMO technology. We analyse both micro- and macro-diversity schemes and develop a hybrid model that switches between macro- and micro-diversity in the case of hard handoff based on a cut-off range of signal-to-noise ratio values. We conclude that our hybrid switched micro-macro MIMO system outperforms classical MIMO systems at the cost of increased hardware and software complexity.Keywords: cooperative multipoint transmission, ergodic capacity, hard handoff, macro-diversity, micro-diversity, multiple-input-multiple output systems, orthogonal frequency division multiplexing
Procedia PDF Downloads 31210990 Significant Reduction in Specific CO₂ Emission through Process Optimization at G Blast Furnace, Tata Steel Jamshedpur
Authors: Shoumodip Roy, Ankit Singhania, M. K. G. Choudhury, Santanu Mallick, M. K. Agarwal, R. V. Ramna, Uttam Singh
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One of the key corporate goals of Tata Steel company is to demonstrate Environment Leadership. Decreasing specific CO₂ emission is one of the key steps to achieve the stated corporate goal. At any Blast Furnace, specific CO₂ emission is directly proportional to fuel intake. To reduce the fuel intake at G Blast Furnace, an initial benchmarking exercise was carried out with international and domestic Blast Furnaces to determine the potential for improvement. The gap identified during the exercise revealed that the benchmark Blast Furnaces operated with superior raw material quality than that in G Blast Furnace. However, since the raw materials to G Blast Furnace are sourced from the captive mines, improvement in the raw material quality was out of scope. Therefore, trials were taken with different operating regimes, to identify the key process parameters, which on optimization could significantly reduce the fuel intake in G Blast Furnace. The key process parameters identified from the trial were the Stoichiometric Oxygen Ratio, Melting Capacity ratio and the burden distribution inside the furnace. These identified process parameters were optimized to bridge the gap in fuel intake at G Blast Furnace, thereby reducing specific CO₂ emission to benchmark levels. This paradigm shift enabled to lower the fuel intake by 70kg per ton of liquid iron produced, thereby reducing the specific CO₂ emission by 15 percent.Keywords: benchmark, blast furnace, CO₂ emission, fuel rate
Procedia PDF Downloads 28010989 The Combined Influences of Salinity, Light and Nitrogen Limitation on the Growth and Biochemical Composition of Nannochloropsis sp. and Tetraselmis sp., Isolated from Penang National Park Coastal Waters, Malaysia
Authors: Mohamed M. Alsull
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In the present study, two microalgae species “Nannochloropsis sp. and Tetraselmis sp.” isolated from Penang National Park coastal waters, Malaysia; were cultivated under combined various laboratory conditions “salinity, light, nitrogen limitation and starvation”. Growth rate, dry weight, chlorophyll a content, total lipid and protein contents, were estimated at mid exponential growth phase. Both Nannochloropsis sp. and Tetraselmis sp. showed remarkable decrease in growth rate, chlorophyll a content and protein content companied with increase in lipid content under nitrogen limitation and starvation conditions. Maintaining Nannochloropsis sp. under salinity 15‰ caused only significant decrease in total protein content; while Tetraselmis sp. grown at the same salinity caused decrease in the growth rate, chlorophyll a, dry weight and total protein content only when nitrogen was available.Keywords: biochemical composition, light, microalgae, nitrogen limitation, salinity
Procedia PDF Downloads 42710988 Implementation Association Rule Method in Determining the Layout of Qita Supermarket as a Strategy in the Competitive Retail Industry in Indonesia
Authors: Dwipa Rizki Utama, Hanief Ibrahim
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The development of industry retail in Indonesia is very fast, various strategy was undertaken to boost the customer satisfaction and the productivity purchases to boost the profit, one of which is implementing strategies layout. The purpose of this study is to determine the layout of Qita supermarket, a retail industry in Indonesia, in order to improve customer satisfaction and to maximize the rate of products’ sale as a whole, so as the infrequently purchased products will be purchased. This research uses a literature study method, and one of the data mining methods is association rule which applied in market basket analysis. Data were tested amounted 100 from 160 after pre-processing data, so then the distribution department and 26 departments corresponding to the data previous layout will be obtained. From those data, by the association rule method, customer behavior when purchasing items simultaneously can be studied, so then the layout of the supermarket based on customer behavior can be determined. Using the rapid miner software by the minimal support 25% and minimal confidence 30% showed that the 14th department purchased at the same time with department 10, 21st department purchased at the same time with department 13, 15th department purchased at the same time with department 12, 14th department purchased at the same time with department 12, and 10th department purchased at the same time with department 14. From those results, a better supermarket layout can be arranged than the previous layout.Keywords: industry retail, strategy, association rule, supermarket
Procedia PDF Downloads 18910987 The Effect of Vitamin D Supplementation on Prostate Cancer: A Systematic Review and Meta-Analysis of Clinical Trials
Authors: Simin Shahvazi, Sepideh Soltani, Seyed Mehdi Ahmadi, Russell J. De Souza, Amin Salehi-Abargouei
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Background and Objectives: Vitamin D has received attention for its potential to disrupt cancer processes such as attenuating cell proliferation and exacerbating differentiation and apoptosis. However, whether there exists a role for vitamin D in the treatment of prostate cancer specifically remains controversial. We systematically review the literature to assess whether supplementation with vitamin D influences PSA response and overall survival in patients with prostate cancer. Methods: We searched PubMed, Scopus, ISI Web of Science and Google scholar from inception through up to 10 September 2017 for both before-and-after and randomized trials that evaluated the effect of vitamin D supplementation on the prostate specific antigen (PSA) response rate in participants with prostate cancer. The DerSimonian and Laird, inverse-weighted random-effects model was used to pool effect estimates from the studies. Heterogeneity and potential publication bias were evaluated. Subgroup analyses were also performed. Results: Twenty-two studies (16 before-after and 6 randomized controlled trials) were found and included in meta-analysis. The analysis on controlled clinical trials revealed that PSA change from baseline [weighted mean difference (WMD) = -1.66 ng/ml, 95%CI: -0.69, 0.36, P= 0.543)], PSA response (RR=1.18, 95%CI: 0.97, 1.45, P=0.104) and mortality rate (risk ratio (RR) = 1.05, 95% CI: 0.81-1.36; P=0.713) was not significantly different between vitamin D supplementation and placebo groups. Single arm trials revealed that vitamin D supplementation had had a modest effect on PSA response rate: 19% of those enrolled had at least a 50% reduction in PSA by the end of treatment (95% CI: 7% to 31%; p=0.002). Conclusion: We found that vitamin D modestly increases the PSA response rate in single arm studies. No effect on serum PSA levels, PSA response and mortality was seen in randomized controlled clinical trials. It does not seem patients with prostate cancer benefit from vitamin D supplementation.Keywords: mortality, prostatic neoplasms, PSA response, vitamin D
Procedia PDF Downloads 19510986 Mediation in Turkish Health Law for Healthcare Disputes
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In order to prevent overburdened courts, rising costs of litigation, and lengthy trial resolutions, the Law on Mediation for Civil Disputes was enacted, which was aimed at defining the procedure and guiding principles for dispute resolutions under Civil Law, in 2012. This “Mediation Code” also applies for civil healthcare disputes in Turkey. Aside from mediation, reconciliation, governed by Articles 253-255 of Criminal Procedure Law, has emerged as an alternative way to resolve criminal medical disputes, but the difference between mediation and conciliation is mostly procedural. This article deals with mediation in Turkish health law and aspect of medical malpractice mediation in Turkey. In addition, this study examines the issue of mediation in health law from both a legal and normative point of view, including codes of mediation which regulate both the structural and professional practice of mediation providers. As a result, although there is not official record about success rate of medical malpractice litigations and malpractice mediation in Turkey, it is widely accepted that the success rate for medical malpractice cases is relatively low compared to other personal injury cases even if it is generally considered that medical malpractice case filings have gradually increased recently. According to the Justice Ministry’s Department of Mediation in Turkey, 719 civil disputes have referred to mediators since 2013 (when the first mediation law came into force) with a 98% success rate.Keywords: malpractice mediation, medical disputes, reconciliation, health litigation, Turkish health law
Procedia PDF Downloads 31210985 A New Lateral Load Pattern for Pushover Analysis of RC Frame Structures
Authors: Mohammad Reza Ameri, Ali Massumi, Mohammad Haghbin
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Non-linear static analysis, commonly referred to as pushover analysis, is a powerful tool for assessing the seismic response of structures. A suitable lateral load pattern for pushover analysis can bring the results of this simple, quick and low-cost analysis close to the realistic results of nonlinear dynamic analyses. In this research, four samples of 10- and 15 story (two- and four-bay) reinforced concrete frames were studied. The lateral load distribution patterns recommended in FEMA 273/356 guidelines were applied to the sample models in order to perform pushover analyses. The results were then compared to the results obtained from several nonlinear incremental dynamic analyses for a range of earthquakes. Finally, a lateral load distribution pattern was proposed for pushover analysis of medium-rise reinforced concrete buildings based on the results of nonlinear static and dynamic analyses.Keywords: lateral load pattern, nonlinear static analysis, incremental dynamic analysis, medium-rise reinforced concrete frames, performance based design
Procedia PDF Downloads 47610984 On the Transition of Europe’s Power Sector: Economic Consequences of National Targets
Authors: Geoffrey J. Blanford, Christoph Weissbart
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The prospects for the European power sector indicate that it has to almost fully decarbonize in order to reach the economy-wide target of CO2-emission reduction. We apply the EU-REGEN model to explain the penetration of RES from an economic perspective, their spatial distribution, and the complementary role of conventional generation technologies. Furthermore, we identify economic consequences of national energy and climate targets. Our study shows that onshore wind power will be the most crucial generation technology for the future European power sector. Its geographic distribution is driven by resource quality. Gas power will be the major conventional generation technology for backing-up wind power. Moreover, a complete phase out of coal power proves to be not economically optimal. The paper demonstrates that existing national targets have a negative impact, especially on the German region with higher prices and lower revenues. The remaining regions profit are hardly affected. We encourage an EU-wide coordination on the expansion of wind power with harmonized policies. Yet, this requires profitable market structures for both, RES and conventional generation technologies.Keywords: European, policy evaluation, power sector investment, technology choices
Procedia PDF Downloads 28410983 Pharmacokinetic Study of Clarithromycin in Human Female of Pakistani Population
Authors: Atifa Mushtaq, Tanweer Khaliq, Hafiz Alam Sher, Asia Farid, Anila Kanwal, Maliha Sarfraz
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The study was designed to assess the various pharmacokinetic parameters of a commercially available clarithromycin Tablet (Klaricid® 250 mg Abbot, Pakistan) in plasma sample of healthy adult female volunteers by applying a rapid, sensitive and accurate HPLC-UV analytical method. The human plasma samples were evaluated by using an isocratic High Performance Liquid Chromatography (HPLC) system of Sykam consisted of a pump with a column C18 column (250×4.6mn, 5µm) UV-detector. The mobile phase comprises of potassium dihydrogen phosphate (50 mM, pH 6.8, contained 0.7% triethylamine), methanol and acetonitrile (30:25:45, v/v/v) was delivered with injection volume of 20µL at flow rate of 1 mL/min. The detection was performed at λmax 275 nm. By applying this method, important pharmacokinetic parameters Cmax, Tmax, Area under curve (AUC), half-life (t1/2), , Volume of distribution (Vd) and Clearance (Cl) were measured. The parameters of pharmacokinetics of clarithromycin were calculated by software (APO) pharmacological analysis. Maximum plasma concentrations Cmax 2.78 ±0.33 µg/ml, time to reach maximum concentration tmax 2.82 ± 0.11 h and Area under curve AUC was 20.14 h.µg/ml. The mean ± SD values obtained for the pharmacokinetic parameters showed a significant difference in pharmacokinetic parameters observed in previous literature which emphasizes the need for dose adjustment of clarithromycin in Pakistani population.Keywords: Pharmacokinetc, Clarothromycin, HPLC, Pakistan
Procedia PDF Downloads 10810982 On the Development of a Homogenized Earthquake Catalogue for Northern Algeria
Authors: I. Grigoratos, R. Monteiro
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Regions with a significant percentage of non-seismically designed buildings and reduced urban planning are particularly vulnerable to natural hazards. In this context, the project ‘Improved Tools for Disaster Risk Mitigation in Algeria’ (ITERATE) aims at seismic risk mitigation in Algeria. Past earthquakes in North Algeria caused extensive damages, e.g. the El Asnam 1980 moment magnitude (Mw) 7.1 and Boumerdes 2003 Mw 6.8 earthquakes. This paper will address a number of proposed developments and considerations made towards a further improvement of the component of seismic hazard. In specific, an updated earthquake catalog (until year 2018) is compiled, and new conversion equations to moment magnitude are introduced. Furthermore, a network-based method for the estimation of the spatial and temporal distribution of the minimum magnitude of completeness is applied. We found relatively large values for Mc, due to the sparse network, and a nonlinear trend between Mw and body wave (mb) or local magnitude (ML), which are the most common scales reported in the region. Lastly, the resulting b-value of the Gutenberg-Richter distribution is sensitive to the declustering method.Keywords: conversion equation, magnitude of completeness, seismic events, seismic hazard
Procedia PDF Downloads 16510981 A Modelling of Main Bearings in the Two-Stroke Diesel Engine
Authors: Marcin Szlachetka, Rafal Sochaczewski, Lukasz Grabowski
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This paper presents the results of the load simulations of main bearings in a two-stroke Diesel engine. A model of an engine lubrication system with connections of its main lubrication nodes, i.e., a connection of its main bearings in the engine block with the crankshaft, a connection of its crankpins with its connecting rod and a connection of its pin and its piston has been created for our calculations performed using the AVL EXCITE Designer. The analysis covers the loads given as a pressure distribution in a hydrodynamic oil film, a temperature distribution on the main bush surfaces for the specified radial clearance values as well as the impact of the force of gas on the minimum oil film thickness in the main bearings depending on crankshaft rotational speeds and temperatures of oil in the bearings. One of the main goals of the research has been to determine whether the minimum thickness of the oil film at which fluid friction occurs can be achieved for each value of crankshaft speed. Our model calculates different oil film parameters, i.e., its thickness, a pressure distribution there, the change in oil temperature. Additional enables an analysis of an oil temperature distribution on the surfaces of the bearing seats. It allows verifying the selected clearances in the bearings of the main engine under normal operation conditions and extremal ones that show a significant increase in temperature above the limit value. The research has been conducted for several engine crankshaft speeds ranging from 1000 rpm to 4000 rpm. The oil pressure in the bearings has ranged 2-5 bar according to engine speeds and the oil temperature has ranged 90-120 °C. The main bearing clearance has been adopted for the calculation and analysis as 0.025 mm. The oil classified as SAE 5W-30 has been used for the simulations. The paper discusses the selected research results referring to several specific operating points and different temperatures of the lubricating oil in the bearings. The received research results show that for the investigated main bearing bushes of the shaft, the results fall within the ranges of the limit values despite the increase in the oil temperature of the bearings reaching 120˚C. The fact that the bearings are loaded with the maximum pressure makes no excessive temperature rise on the bush surfaces. The oil temperature increases by 17˚C, reaching 137˚C at a speed of 4000 rpm. The minimum film thickness at which fluid friction occurs has been achieved for each of the operating points at each of the engine crankshaft speeds. 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: diesel engine, main bearings, opposing pistons, two-stroke
Procedia PDF Downloads 13710980 Automated Classification of Hypoxia from Fetal Heart Rate Using Advanced Data Models of Intrapartum Cardiotocography
Authors: Malarvizhi Selvaraj, Paul Fergus, Andy Shaw
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Uterine contractions produced during labour have the potential to damage the foetus by diminishing the maternal blood flow to the placenta. In order to observe this phenomenon labour and delivery are routinely monitored using cardiotocography monitors. An obstetrician usually makes the diagnosis of foetus hypoxia by interpreting cardiotocography recordings. However, cardiotocography capture and interpretation is time-consuming and subjective, often lead to misclassification that causes damage to the foetus and unnecessary caesarean section. Both of these have a high impact on the foetus and the cost to the national healthcare services. Automatic detection of foetal heart rate may be an objective solution to help to reduce unnecessary medical interventions, as reported in several studies. This paper aim is to provide a system for better identification and interpretation of abnormalities of the fetal heart rate using RStudio. An open dataset of 552 Intrapartum recordings has been filtered with 0.034 Hz filters in an attempt to remove noise while keeping as much of the discriminative data as possible. Features were chosen following an extensive literature review, which concluded with FIGO features such as acceleration, deceleration, mean, variance and standard derivation. The five features were extracted from 552 recordings. Using these features, recordings will be classified either normal or abnormal. If the recording is abnormal, it has got more chances of hypoxia.Keywords: cardiotocography, foetus, intrapartum, hypoxia
Procedia PDF Downloads 21610979 Hydrodynamics of Dual Hybrid Impeller of Stirred Reactor Using Radiotracer
Authors: Noraishah Othman, Siti K. Kamarudin, Norinsan K. Othman, Mohd S. Takriff, Masli I. Rosli, Engku M. Fahmi, Mior A. Khusaini
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The present work describes hydrodynamics of mixing characteristics of two dual hybrid impeller consisting of, radial and axial impeller using radiotracer technique. Type A mixer, a Rushton turbine is mounted above a Pitched Blade Turbine (PBT) at common shaft and Type B mixer, a Rushton turbine is mounted below PBT. The objectives of this paper are to investigate the residence time distribution (RTD) of two hybrid mixers and to represent the respective mixers by RTD model. Each type of mixer will experience five radiotracer experiments using Tc99m as source of tracer and scintillation detectors NaI(Tl) are used for tracer detection. The results showed that mixer in parallel model and mixers in series with exchange can represent the flow model in mixer A whereas only mixer in parallel model can represent Type B mixer well than other models. In conclusion, Type A impeller, Rushton impeller above PBT, reduced the presence of dead zone in the mixer significantly rather than Type B.Keywords: hybrid impeller, residence time distribution (RTD), radiotracer experiments, RTD model
Procedia PDF Downloads 35810978 Treatment of Feline Infectious Peritonitis in Cats with Molnupiravir: Clinical Observations and Outcomes For 54 Cases
Authors: T. M. Clark, S. J. Coggins, R. Malik, J. King, R. Korman
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Objectives: This observational study investigated the use of molnupiravir for treatment of cats with naturally occurring feline infectious peritonitis. Methods: From September 2022 to February 2024, 66 cats diagnosed with FIP across 32 veterinary practices, mainly in Australia, were enrolled. Of these, 54 cats met the inclusion criteria. Complete remission was defined by the resolution of clinical signs and normalisation of A:G ratio (to ≥0.6). Presumptive remission was defined as sustained resolution of FIP-related clinical signs for at least 100 days post cessation of antiviral therapy. Results: In Cohort 1, 18 cats were treated with molnupiravir monotherapy. Thirteen achieved complete remission and three attained presumptive remission, resulting in an overall remission rate of 89% and a provisional cure rate of 72%, with three relapses. Cohort 2 included 29 cats treated with a short induction course of GS-441524 and/or remdesivir before switching to molnupiravir; 23 attained complete remission, and two achieved presumptive remission. The overall cure rate was 86% with no relapses. Seven cats in cohort 3 were initially treated with extended courses of GS-441524, remdesivir, and/or mefloquine and experienced treatment failure or relapse. Molnupiravir was introduced as a rescue therapy; 6 achieved complete remission and 1 achieved presumed remission, resulting in a 100% cure rate with no relapses. Few adverse effects were reported, with the most notable including neutropenia, transient elevations in hepatic enzymes, and polydipsia/polyuria. Conclusion and Relevance: Molnupiravir as a monotherapy, or in combination with other antivirals, represents an accessible, effective treatment for FIP when given at a dosage of 10-15 mg/kg BID. Success occurred across various presentations of FIP, including cases with ocular and neurological involvement.Keywords: feline infectious peritonitis, FIP, molnupiravir, nucleoside analogue, antiviral
Procedia PDF Downloads 1910977 Removal of Copper from Wastewaters by Nano-Micro Bubble Ion Flotation
Authors: R. Ahmadi, A. Khodadadi, M. Abdollahi
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The removal of copper from a dilute synthetic wastewater (10 mg/L) was studied by ion flotation at laboratory scale. Anionic sodium dodecyl sulfate (SDS) was used as a collector and ethanol as a frother. Different parameters such as pH, collector and frother concentrations, foam height and bubble size distribution (multi bubble ion flotation) were tested to determine the optimum flotation conditions in a Denver type flotation machine. To see into the effect of bubbles size distribution in this paper, a nano-micro bubble generator was designed. The nano and microbubbles that are generated in this way were combined with normal size bubbles generated mechanically. Under the optimum conditions (concentration of SDS: 192mg/l, ethanol: 0.5%v/v, pH value: 4 and froth height=12.5 cm) the best removal obtained for the system Cu/SDS with a dry foam (water recovery: 15.5%) was 85.6%. Coalescence of nano-microbubbles with bubbles of normal size belonging to mechanical flotation cell improved the removal of Cu to a maximum floatability of 92.8% and reduced the water recovery to a 13.1%.The flotation time decreased considerably at 37.5% when the multi bubble ion flotation was used.Keywords: froth flotation, copper, water treatment, optimization, recycling
Procedia PDF Downloads 50210976 A Model to Assist Military Mission Planners in Identifying and Assessing Variables Impacting Food Security
Authors: Lynndee Kemmet
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The U.S. military plays an increasing role in supporting political stability efforts, and this includes efforts to prevent the food insecurity that can trigger political and social instability. This paper presents a model that assists military commanders in identifying variables that impact food production and distribution in their areas of operation (AO), in identifying connections between variables and in assessing the impacts of those variables on food production and distribution. Through use of the model, military units can better target their data collection efforts and can categorize and analyze data within the data categorization framework most widely-used by military forces—PMESII-PT (Political, Military, Economic, Infrastructure, Information, Physical Environment and Time). The model provides flexibility of analysis in that commanders can target analysis to be highly focused on a specific PMESII-PT domain or variable or conduct analysis across multiple PMESII-PT domains. The model is also designed to assist commanders in mapping food systems in their AOs and then identifying components of those systems that must be strengthened or protected.Keywords: food security, food system model, political stability, US Military
Procedia PDF Downloads 196