Search results for: residual sodium chloride

Authors: Jagdeep Nayak, Biswajit Paul, Anup Gupta

Abstract:

Characterization of coal refuses to fly ash, and steel slag from steel industries have been performed to develop a mixture of both these materials to enhance strength properties of their utilization in other sectors like mine fill, construction work, etc. A large amount of Linz-Donawitz (LD) slag and fly ash waste are generated from steel and thermal power industries respectively. Management of these wastes is problematic, and their reutilization may provide a sustainable waste management option. LD slag and fly ash mixed in different proportions were tested to analyse the micro structural improvement and hardening rate of the matrix. Mixing of activators such as sodium hydroxide and potassium silicate with silica-alumina of LD slag-fly ash mixture, geopolymeric structure were found to be developed. The effect of geo-polymerization behaviour and subsequent structural rearrangement has been studied using compressibility; shear strength and permeability tests followed by micro-graphical analysis. Densification in the mixture was observed along with an improvement of geotechnical properties due to the addition of LD slag. Due to suitable strength characteristics of these two waste materials as mixture, it can be used in the various construction field or may be used as a filling material in mine voids.

Keywords: LD slag, fly-ash, geopolymer, strength property, compressibility

Procedia PDF Downloads 385

Authors: Abhinav Srivastava, Hima Harode, Chandan Kumar Saha

Abstract:

The principal ingredient of an optical fiber is quartz glass. The quality of the optical fiber decreases if impure foreign substances are attached to its preform surface. If residual strain inside a preform is significant, it cracks with a small impact during drawing or transporting. Furthermore, damages and unevenness on the surface of an optical fiber base material break the fiber during drawing. The present work signifies that chlorine pre-treatment enhances mechanical properties of the optical fiber glass. FTIR (Fourier-Transform Infrared Spectroscopy) results show that chlorine gas chemically modifies the structure of silica clad; chlorine is known to soften glass. Metallic impurities on the preform surface likely formed volatile metal chlorides due to chlorine pretreatment at elevated temperature. The chlorine also acts as a drying agent, and therefore the preform surface is anticipated to be water deficient and supposedly avoids particle adhesion on the glass surface. The Weibull analysis of long length tensile strength demarcates a substantial shift in its knee. The higher dynamic fatigue n-value also indicated surface crack healing.

Keywords: mechanical strength, optical fiber glass, FTIR, Weibull analysis

Procedia PDF Downloads 169

Authors: G. T. Mudashiru, Mayowa P. Ibitola

Abstract:

Investigation was carried out at Ikorodu North local council development area of Lagos state using physiochemical parameters to study the quality drinking water. It was ascertained that the human functions and activities were dependent on the continuous and availability of good drinking water. Six water samples were collected at six different boreholes from various outlets and homes in Ikorodu North local council development area. Lagos state Nigeria. Analysis was carried out to determine the purity of water for domestic use. Physicochemical properties evaluation was adapted using standard chemical methods. A number of parameters such as PH, turbidity, conductivity, total dissolved solids, color, chloride, sulphate, nitrate, hardness were determined. Heavy metals such as Zn, Mg, Fe, Pb, Hg, and Mn as well as total coliform counts were observed. The resulted values of each parameter were justified with World Health Organization (WHO) and Lagos state water regulatory commission LSWRC standard values for quantitative comparison. The result reveals that all the water had pH value well below the WHO maximum permissible level for potable water. Other physicochemical parameters were within the safe limit of WHO standard showing the portability nature of the water. It can be concluded that though the water is potable, there should be a kind of treatment of the water before consumption to prevent outbreak of diseases.

Keywords: drinking water, physiology, boreholes, heavy metals, domestic

Procedia PDF Downloads 208

Authors: Khaled M. Khleifat

Abstract:

An extracellular methanol and ethanol tolerant lipase producing bacterial strain K5b4 was isolated from soil samples contaminated with hydrocarbon residues. It was identified by using morphological and biochemical characteristics and 16srRNA technique as Acinetobacter species. The immobilized lipase from Acinetobacter sp. K5b4 retained more than 98% of its residual activity after incubation with pure methanol and ethanol for 24 hours. The highest hydrolytic activity of the immobilized enzyme was obtained in the presence of 75% (v/v) methanol in the assay solution. In contrary, the enzyme was able to maintain its original activity up to only 25% (v/v) ethanol whereas at elevated concentrations of 50 and 75% (v/v) the enzyme activity was reduced to 10 and 40%, respectively. Maximum lipase activity of 31.5 mU/mL was achieved after 48 hr cultivation when the optimized medium (pH 7.0) that composed of 1.0% (w/v) olive oil, 0.2% (w/v) glycerol, 0.15% (w/v) yeast extract, and 0.05% (w/v) NaCl was inoculated with 0.4% (v/v) seed culture and incubated at 30°C and 150 rpm agitation speed. However, the presence of CaCl2 in the growth media did not show any inhibitory or stimulatory effect on the enzyme production as it compared to the control experiment. Meanwhile, the other mineral salts MgCl2, MnCl2, KCl and CoCl2 were negatively affected the production of lipase enzyme. The inhibition of lipase production from Acinetobacter sp. K5b4 in presence of glucose suggesting that lipase gene expression is prone to catabolic repression.

Keywords: K5B4, methanol and ethanol, acinetobacter, morphological

Procedia PDF Downloads 313

Authors: M. N. Hanina, M. Hairul Shahril, I. Ismatul Nurul Asyikin, A. K. Abdul Jalil, M. R. Salina, M. R. Maryam, M. Rosfarizan

Abstract:

The extracellular proteins secreted by bacteria may be increased in stressful surroundings, such as in the presence of antibiotics. It appears that many antibiotics, when used at low concentrations, have in common the ability to activate or repress gene transcription, which is distinct from their inhibitory effect. There have been comparatively few studies on the potential of antibiotics as a specific chemical signal that can trigger a variety of biological functions. Therefore, this study was carried out to determine the effect of Streptomycin Sulfate in regulating extracellular proteins secreted by Bacillus subtilis ATCC21332. Results of Microdilution assay showed that the Minimum Inhibition Concentration (MIC) of Streptomycin Sulfate on B. subtilis ATCC21332 was 2.5 mg/ml. The bacteria cells were then exposed to Streptomycin Sulfate at concentration of 0.01 MIC before being further incubated for 48h to 72 h. The extracellular proteins secreted were then isolated and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Proteins profile revealed that three additional bands with approximate sizes of 30 kDa, 22 kDa and 23 kDa were appeared for the treated bacteria with Streptomycin Sulfate. Thus, B. subtilis ATCC21332 in stressful condition with the presence of Streptomycin Sulfate at low concentration could induce the extracellular proteins secretion.

Keywords: Bacillus subtilis ATCC21332, streptomycin sulfate, extracellular proteins, antibiotics

Procedia PDF Downloads 277

Authors: Rama Bhattacharyya, S. N. Ojha, Umesh K. Singh

Abstract:

Anthropogenic control on groundwater chemistry has emerged as a critical concern now-a-days, especially in the industrial areas. In view of this, a comprehensive study on the distribution of the heavy metal in the groundwater was conducted to investigate the impact of urbanization in the aquatic media. Water samples either from well or borehole from Fourty different sites in and around, Durgapur, West Bengal were collected for this purpose. The samples were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for Calcium (Ca), Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Sodium (Na), Nickel (Ni), Lead (Pb), Zinc (Zn) content and the levels were compared with WHO specified maximum contaminant level as well as permissible limits given by the Bureau of Indian Standards (BIS). The result obtained from the present study indicates a significant risk to the population of this important emerging ‘smart city’ of eastern India. Because of the toxicity of these metals and the fact that for many tube-wells, dug-wells and bore-wells are the only sources of the water supply for a major fraction of the population in this environment. In this study, an attempt has been made to develop metal contamination risk map.

Keywords: heavy metals, ground water, maximum contamination level, ICP-MS

Procedia PDF Downloads 208

Authors: Shyam Ranjan Kumar, Shashikant Rajpal

Abstract:

Zinc Telluride (ZnTe) is a binary II-VI direct band gap semiconducting material. This semiconducting material has several applications in sensors, photo-electrochemical devices and photovoltaic solar cell. In this study, Zinc telluride (ZnTe) thin films were deposited on nickel substrate by electrodeposition technique using potentiostat/galvanostat at -0.85 V using AR grade of Zinc Chloride (ZnCl2), Tellurium Tetrachloride (TeCl4) in non-aqueous bath. The developed films were physically stable and showed good adhesion. The as deposited ZnTe films were annealed at 400ºC in air. The solid state properties and optical properties of the as deposited and annealed films were carried out by XRD, EDS, SEM, AFM, UV–Visible spectrophotometer, and photoluminescence spectrophotometer. The diffraction peak observed at 2θ = 49.58° with (111) plane indicate the crystalline nature of ZnTe film. Annealing improves the crystalline nature of the film. Compositional analysis reveals the presence of Zn and Te with tellurium rich ZnTe film. SEM photograph at 10000X shows that grains of film are spherical in nature and densely distributed over the surface. The average roughness of the film is measured by atomic force microscopy and it is nearly equal to 60 nm. The direct wide band gap of 2.12 eV is observed by UV-Vis spectroscopy. Luminescence peak of the ZnTe films are also observed in as deposited and annealed case.

Keywords: annealing, electrodeposition, optical properties, thin film, XRD, ZnTe

Procedia PDF Downloads 187

Authors: Nasiru Inuwa, Haruna Usman Modibbo, Yahya Zakari Abdullahi

Abstract:

The purpose of this paper is to investigate the effects of foreign direct investment (FDI), economic growth on carbon emissions in context of WAIFEM member countries. The Im-Pesaran-Shin panel unit root test, Kao residual based test panel cointegration technique and panel Granger causality tests over the period 1980-2012 within a multivariate framework were applied. The results of cointegration test revealed a long run equilibrium relationship among CO2 emissions, economic growth and foreign direct investment. The results of Granger causality tests revealed a unidirectional causality running from economic growth to CO2 emissions for the panel of WAIFEM countries at the 5% level. Also, Granger causality runs from economic growth to foreign direct investment without feedback. However, no causality relationship between foreign direct investment and CO2 emissions for the panel of WAIFEM countries was observed. The study therefore, suggest that policy makers from WAIFEM member countries should design policies aim at attracting more foreign direct investments inflow as well the adoption of cleaner production technologies in order to reduce CO2 emissions.

Keywords: economic growth, CO2 emissions, causality, WAIFEM

Procedia PDF Downloads 564

Authors: Je Young Lee, Hee Sung Kim, Kwang Ho Choi, Joonhoo Lim, Sebum Chun, Hyung Keun Lee

Abstract:

A purpose of this study is to develop efficient detection method for Global Navigation Satellite Systems (GNSS) applications based on adaptive estimation. Due to dependence of radio frequency signals, GNSS measurements are dominated by systematic errors in receiver’s operating environment. Thus, to utilize GNSS for aerospace or ground vehicles requiring high level of safety, unhealthy measurements should be considered seriously. For the reason, this paper proposes adaptive fault detection method to deal with unhealthy measurements in various harsh environments. By the proposed method, the test statistics for fault detection is generated by estimated measurement noise. Pseudorange and carrier-phase measurement noise are obtained at time propagations and measurement updates in process of Carrier-Smoothed Code (CSC) filtering, respectively. Performance of the proposed method was evaluated by field-collected GNSS measurements. To evaluate the fault detection capability, intentional faults were added to measurements. The experimental result shows that the proposed detection method is efficient in detecting unhealthy measurements and improves the accuracy of GNSS positioning under fault occurrence.

Keywords: adaptive estimation, fault detection, GNSS, residual

Procedia PDF Downloads 564

Authors: R. Malathy

Abstract:

High performance concrete is not only characterized by its high strength, workability, and durability but also by its smartness in performance without human care since the first day. If the concrete can cure on its own without external curing without compromising its strength and durability, then it is said to be high performance self-curing concrete. In this paper, an attempt is made on the performance study of internally cured concrete using biomaterials, namely Spinacea pleracea and Calatropis gigantea as self-curing agents, and it is compared with the performance of concrete with existing self-cure chemical, namely polyethylene glycol. The present paper focuses on workability, strength, and durability study on M20, M30, and M40 grade concretes replacing 30% of fly ash for cement. The optimum dosage of Spinacea pleracea, Calatropis gigantea, and polyethylene glycol was taken as 0.6%, 0.24%, and 0.3% by weight of cement from the earlier research studies. From the slump tests performed, it was found that there is a minimum variation between conventional concrete and self-cured concrete. The strength activity index is determined by keeping compressive strength of conventionally cured concrete for 28 days as unity and observed that, for self-cured concrete, it is more than 1 after 28 days and more than 1.15 after 56 days because of secondary reaction of fly ash. The performance study of concretes in aggressive environment like acid attack, sea water attack, and chloride attack was made, and the results are positive and encouraging in bio-self-cured concretes which are ecofriendly, cost effective, and high performance materials.

Keywords: bio materials, Calatropis gigantea, self curing concrete, Spinacea oleracea

Procedia PDF Downloads 341

Authors: Ewa Rudnik

Abstract:

Poster shows a comparison of hydrometallurgical routes of copper recovery from low-grade e-waste. Electronic scrap was smelted to produce Cu–Zn–Ag alloy. The alloy was then treated in the following ways: (a) anodic dissolution with simultaneous metal electrodeposition using ammoniacal and sulfuric acid solutions. This resulted in the separation of metals, where lead, silver and tin accumulated mainly in the slimes, while copper was transferred to the electrolyte and then recovered on the cathode. The best conditions of the alloy treatment were obtained in the sulfuric acid, where the final product was metal of high purity (99% Cu) at the current efficiency of 90%. (b) leaching in ammoniacal solutions of various compositions and then copper electrowinning. Alloy was leached in chloride, carbonate, sulfate and thiosulfate baths. This resulted in the separation of the metals, wherein copper and zinc were transferred to the electrolyte, while metallic tin and silver as well as lead salts remained in the slimes. Copper was selectively recovered from the ammoniacal solutions by the electrolysis, leaving zinc ions in the electrolyte. The best conditions of the alloy treatment were obtained in the ammonia-carbonate system, where the final product was copper of high purity (99.9%) at the current efficiency of 60%. Thiosulfate solution was not applicable for the leaching of the copper alloy due to secondary reactions of the formation of copper (I) thiosulfate complexes and precipitation of copper (I) sulfide.

Keywords: alloy, electrolysis, e-waste, leaching

Procedia PDF Downloads 362

Authors: Wu Xiaojun, Liu Ruiping, Yu Xingzhan, Wu Qian

Abstract:

In precision grinding, utilizing the elastic matrix ball has higher processing efficiency and better superficial quality than traditional grinding. The diversity of characteristics which elastic abrasive tool contact with bend surface results in irregular wear abrasion，and abrasive tool machining status get complicated. There is no theoretical interpretation that parameters affect the grinding accuracy.Aiming at corrosion resistance, wear resistance and other characteristics of M 300 material, it is often used as a material on aerospace precision components. The paper carried out grinding and polishing experiments by using material of M 300,to theoretically show the relationship between stress magnitude and grinding efficiency，and predict the optimal combination of grinding parameter for effective grinding, just for the high abrasion resistance features of M 300, analyzing the micro-contact of elastic ball abrasive tool (Whetstone), using mathematical methods deduce the functional relationship between residual peak removal rate and the main parameters which impact the grinding accuracy on the plane case.Thus laying the foundation for the study of elastic abrasive prediction and compensation.

Keywords: flexible abrasive tool, polishing parameters, Hertz theory, removal rate

Procedia PDF Downloads 538

Authors: Lesa A. Thompson, Yoshinori Ikenaka, Victor Wepener, Mayumi Ishizuka

Abstract:

One method for controlling malaria in endemic regions is the killing of vector mosquitoes using pesticides such as DDT in indoor residual spraying (IRS). This study was carried out to investigate the presence of and human health risk due to DDT and its metabolites (collectively, DDTs) contaminating human food sources in areas where DDT is used for IRS. Free-range chicken products (meat and eggs) were collected from homesteads in KwaZulu-Natal Province in the northeast of South Africa, and fish meat samples from Maputo Bay in neighbouring Mozambique. Samples were analysed for DDTs (o,p’-DDT, p,p’-DDT, o,p’-DDD, p,p’-DDD, o,p’-DDE and p,p’-DDE) using a gas chromatograph with electron capture detector (GC-ECD). DDTs were detected in all food types, with the predominant congener being p,p’-DDE. The presence of p,p’-DDT confirmed recent release of DDT into the environment. By using concentration levels detected in foods and national consumption levels, the risk to human health through consumption of such food products was calculated. In order of risk level, these were: chicken eggs > chicken meat > fish meat. Human risk (carcinogenic) values greater than one suggest there is an increased health risk through consumption of these foods.

Keywords: DDT, food contamination, human health risk, Mozambique, South Africa

Procedia PDF Downloads 333

Authors: Mitia Ramarosaona, Sylvie Castagnet, Damien Halm, Henri-Alexandre Cayzac, Nicolas Dufaure, Philippe Papin

Abstract:

In light of the ongoing energy transition, 'Infrastructure developments' for hydrogen transportation and storage raise studies on the materials employed for hyperbaric vessels. Type IV tanks represent the most mature choice for gaseous hydrogen storage at high pressure – 70MPa. These tanks are made of a composite shell and an internal hydrogen-exposed polymer liner. High pressure conditions lead to severe mechanical loading requiring high resistance. Liner is in contact with hydrogen and undergoes compression – decompression cycles during system filling and emptying. Stresses induced by this loading, coupled with hydrogen diffusion, were found to cause microstructural changes and degradation of mechanical behaviour after decompression phase in some studies on HDPE. These phenomena are similar to those observed in elastomeric components like sealing rings, which can affect permeability and lead to their failure. They may lead to a hydrogen leak, compromising security and tightness of the tank. While these phenomena have been identified in elastomers, they remain less addressed in thermoplastics and consequences post-decompression damages on mechanical behaviour and to the best of author's knowledge was not studied either. Different additives are also included in liner formulation to improve its behaviour. This study aimed to better understand damage micro-mechanisms in PA11s exposed to hydrogen compression-decompression cycles and understand if additives influence their resistance. Samples of pure, plasticized and impact-modified PA11s are exposed to 1, 3 and 8 pressure cycles including hydrogen saturation at 70MPa followed by severe 15-second decompression. After hydrogen exposure and significantly later than full desorption, the residual mechanical behaviour is characterized through impact and monotonic tensile tests, on plain and notched samples. Several techniques of microstructure and micro-nano damage characterization are carried out to assess whether changes in macroscopic properties are driven by microstructural changes in the crystalline structure (SAXS-WAXS acquisitions and SEM micrographs). Thanks to WAXS acquisition and microscopic observation, the effects due to additives and pressure consequences can be decorrelated. Pure PA11 and PA11 with a low percentage of additives show an increase in stress level at the first yielding point after hydrogen cycles. The amplitude of the stress increase is more important in formulation with additives because of changes in PA11 matrix behavior and environment created by additives actions. Plasticizer modifies chain mobility leading to microstructure changes while other additives, more ductile than PA11, is able to cavitate inside PA11 matrix when undergoing decompression. On plasticized formulation, plasticizer migration are suspected to enhance impact of hydrogen cycling on mechanical behaviour. Compared to the literature on HDPE and elastomers, no damages like cavitation or cracking could be evidenced from SAXS experiments on every PA11 formulation tested. In perspectives, on all formulation, experimental work is underway to confirm influence of residual pressure level after decompression on post-decompression damages level, the aim is to better understand the factors affecting the mechanical behavior of thermoplastics subject to mechanical solicitation from decompression in hydrogen tank liners, not mechanical behaviour of liner in hydrogen tanks directly.

Keywords: additives, hydrogen tank liner, microstructural analysis, PA11

Procedia PDF Downloads 28

Authors: Hyun Ah Yoon, Ji Yeon Kang, Hee Sun Kim, Yeong Soo Shin

Abstract:

Reinforced concrete (RC) shear wall system of residential buildings is popular in South Korea. RC walls are subjected to axial forces in common and the effect of axial forces on the strength loss of the fire damaged walls has not been investigated. This paper aims at investigating temperature distribution on fire damaged concrete walls having different axial loads. In the experiments, a variable of specimens is axial force ratio. RC walls are fabricated with 150mm of wall thicknesses, 750mm of lengths and 1,300mm of heights having concrete strength of 24MPa. After curing, specimens are heated on one surface with ISO-834 standard time-temperature curve for 2 hours and temperature distributions during the test are measured using thermocouples inside the walls. The experimental results show that the temperature of the RC walls exposed to fire increases as axial force ratio increases. To verify the experiments, finite element (FE) models are generated for coupled temperature-structure analyses. The analytical results of thermal behaviors are in good agreement with the experimental results. The predicted displacement of the walls decreases when the axial force increases. 

Keywords: axial force ratio, fire, reinforced concrete wall, residual strength

Procedia PDF Downloads 454

Authors: Dong Zhang, Kang Hai Tan, Aravind Dasari

Abstract:

Increasing concern on environmental sustainability and waste management has driven the construction and building sector towards renewable materials. In this work, we have explored the usage of natural fibers as an alternative to synthetic fibers like polypropylene (PP) in ultra-high performance concrete (UHPC). PP fibers are incorporated into concrete to resist explosive thermal spalling of UHPC during a fire exposure scenario. Experimental studies on the effect of natural fiber on the mechanical properties and spalling resistance of UHCP were conducted. The residual mechanical properties of UHPC with natural fibers were tested after heating to different temperatures. Spalling behavior of UHPC with natural fibers is also assessed by heating the samples according to ISO 834 fire curve. A range of analytical, physical and microscopic characterization techniques was also used on the concrete samples before and after being subjected to elevated temperature to investigate the phase and microstructural change of the sample. The findings show that natural fibers are able to improve fire resistance of UHPC. Adding natural fibers can prevent UHPC from spalling at high temperature. This study provides an alternative, which is at low cost and environmentally friendly, to prevent spalling of UHPC.

Keywords: high temperature, natural fiber, spalling, ultra-high performance concrete

Procedia PDF Downloads 169

Authors: Radka Králová, Libor Kvítek, Václav Ranc, Aleš Panáček, Radek Zbořil

Abstract:

Surface–Enhanced Raman Scattering (SERS) is an optical spectroscopic technique with very good potential for sensitive detection of substances. In this research, active substrates with high enhancement were provided. Novel silver particles (nanostructures) with high roughened, flower–like morphology were prepared by reduction of cation complex [Ag(NH3)2]+ in presence of sodium borohydride as reducing agent and stabilized polyacrylic acid. The products were characterized by UV/VIS absorption spectrophotometry. Special shapes of silver particles were determined by scanning electron microscopy (SEM) and transmission electron spectroscopy (TEM). Dispersions of this particle were put on fixed substrate to producing suitable layer for SERS. Adenine was applied as basic substance whose effect of enhancement on the layer of silver nanostructures was studied. By comparison with our work, the important influence of stabilizers, polyacrylic acid with various molecular weight and concentration, on the transfer of particles and formation of new structure was confirmed.

Keywords: metals, nanostructures, chemical reduction, Raman spectroscopy, optical properties

Procedia PDF Downloads 364

Authors: Mehran Bakhshi, Mohammad Raouf Hosseini, Mohammadhosein Rahimi

Abstract:

The cadmium sulfide nanoparticles were synthesized from the nickel-cadmium cake of a hydrometallurgical zinc producing plant and sodium sulfide as Cd²⁺ and S^-2 sources, respectively. Also, the synthesis process was performed by using the secretions of Bacillus licheniformis as bio-surfactant. Initially, in order to obtain a cadmium rich solution, two following steps were carried out: 1) Alkaline leaching for the removal of zinc oxide from the cake, and 2) acidic leaching to dissolve cadmium from the remained solid residue. Afterward, the obtained CdSO₄ solution was used for the nanoparticle biosynthesis. Nanoparticles were characterized by the energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) to confirm the formation of CdS crystals with cubic structure. Also, transmission electron microscopy (TEM) was applied to determine the particle sizes which were in 2-10 nm range. Moreover, the presence of the protein containing bio-surfactants was approved by using infrared analysis (FTIR). In addition, the absorbance below 400 nm confirms quantum particles’ size. Finally, it was shown that valuable CdS quantum dots could be obtained from the industrial waste products via environment-friendly biological approaches.

Keywords: biosynthesis, cadmium cake, cadmium sulfide, nanoparticle, zinc smelter

Procedia PDF Downloads 297

Authors: Hyohun Kim, Dongwha Shin, Yeonseok Kim, Ji-Su Ahn, Kensuke Nakamura, Dongeun Choi, Byung-Woo Hong

Abstract:

Artefacts are commonly encountered in the imaging process of clinical computed tomography (CT) where the artefact refers to any systematic discrepancy between the reconstructed observation and the true attenuation coefficient of the object. It is known that CT images are inherently more prone to artefacts due to its image formation process where a large number of independent detectors are involved, and they are assumed to yield consistent measurements. There are a number of different artefact types including noise, beam hardening, scatter, pseudo-enhancement, motion, helical, ring, and metal artefacts, which cause serious difficulties in reading images. Thus, it is desired to remove nuisance factors from the degraded image leaving the fundamental intrinsic information that can provide better interpretation of the anatomical and pathological characteristics. However, it is considered as a difficult task due to the high dimensionality and variability of data to be recovered, which naturally motivates the use of machine learning techniques. We propose an image restoration algorithm based on the deep neural network framework where the denoising auto-encoders are stacked building multiple layers. The denoising auto-encoder is a variant of a classical auto-encoder that takes an input data and maps it to a hidden representation through a deterministic mapping using a non-linear activation function. The latent representation is then mapped back into a reconstruction the size of which is the same as the size of the input data. The reconstruction error can be measured by the traditional squared error assuming the residual follows a normal distribution. In addition to the designed loss function, an effective regularization scheme using residual-driven dropout determined based on the gradient at each layer. The optimal weights are computed by the classical stochastic gradient descent algorithm combined with the back-propagation algorithm. In our algorithm, we initially decompose an input image into its intrinsic representation and the nuisance factors including artefacts based on the classical Total Variation problem that can be efficiently optimized by the convex optimization algorithm such as primal-dual method. The intrinsic forms of the input images are provided to the deep denosing auto-encoders with their original forms in the training phase. In the testing phase, a given image is first decomposed into the intrinsic form and then provided to the trained network to obtain its reconstruction. We apply our algorithm to the restoration of the corrupted CT images by the artefacts. It is shown that our algorithm improves the readability and enhances the anatomical and pathological properties of the object. The quantitative evaluation is performed in terms of the PSNR, and the qualitative evaluation provides significant improvement in reading images despite degrading artefacts. The experimental results indicate the potential of our algorithm as a prior solution to the image interpretation tasks in a variety of medical imaging applications. This work was supported by the MISP(Ministry of Science and ICT), Korea, under the National Program for Excellence in SW (20170001000011001) supervised by the IITP(Institute for Information and Communications Technology Promotion).

Keywords: auto-encoder neural network, CT image artefact, deep learning, intrinsic image representation, noise reduction, total variation

Procedia PDF Downloads 186

Authors: Swati Kundu, Seemi Farhat Basir, Luqman A. Khan

Abstract:

Acute and chronic exposure to arsenic and mercury is known to produce vasoconstriction. Pathways involved in this hypercontraction and their relative contribution are not understood. In this study, we measure agonist-induced contraction of isolated rat aorta exposed to arsenic and mercury aorta and delineate pathways mediating this effect. PE-induced hypercontraction of 37% and 32% was obtained with 25 µM As(III) and 6 nM Hg(II), respectively. Isometric contraction measurements in the presence of apocynin, verapamil and sodium nitroprusside indicates that the major cause of increased contraction is reactive oxygen species and depletion of nitric oxide. Calcium influx plays a minor role in both arsenic and mercury caused hypercontraction. In the unexposed aorta, eugenol causes relaxation by inhibiting ROS and elevating NO, linalool by blocking voltage dependent calcium channel (VDCC) and elevating NO, and carvone by blocking calcium influx through VDDC. Since arsenic and mercury caused hypercontraction is mediated by increased ROS and depletion of nitric oxide, we hypothesize that molecules which neutralize ROS or elevate NO will be better ameliorators. In line with this argument, we find eugenol to be the best ameliorator of arsenic and mercury hypercontraction followed by linalool and carvone.

Keywords: carvone, eugenol, linalool, mercury

Procedia PDF Downloads 313

Authors: G. A. Adamu, M. S. Sallau, S. O. Idris, E. B. Agbaji

Abstract:

Drinking water is supplied to Danbatta, Makoda and some parts of Minjibir local government areas of Kano State from the surface water of Thomas Reservoir. The present land use in the catchment area of the reservoir indicates high agricultural activities, fishing, as well as domestic and small scale industrial activities. To study and monitor the quality of surface and drinking water of the area, water samples were collected from the reservoir, treated water at the treatment plant and potable water at the consumer end in three seasons November - February (cold season), March - June (dry season) and July - September (rainy season). The samples were analyzed for physical and chemical parameters, pH, temperature, total dissolved solids (TDS), conductivity, turbidity, total hardness, suspended solids, total solids, colour, dissolved oxygen (DO), biological oxygen demand (BOD), chloride ion (Cl^-) nitrite (NO₂^-), nitrate (NO₃^-), chemical oxygen demand (COD) and phosphate (PO₄^3-). The higher values obtained in some parameters with respect to the acceptable standard set by World Health Organization (WHO) and Nigerian Industrial Standards (NIS) indicate the pollution of both the surface and drinking water. These pollutants were observed to have a negative impact on water quality in terms of eutrophication, largely due to anthropogenic activities in the watershed.

Keywords: surface water, drinking water, water quality, pollution, Thomas reservoir, Kano

Procedia PDF Downloads 286

Authors: Ikenna Charles Onyema, Tolut Prince Bako

Abstract:

A study was carried out in the Atlantic Ocean off the Lighthouse Beach, Lagos. There were monthly and spatial variations in physical and chemical characteristics of the neritic ocean (August - December, 2014). Mean and standard deviation values for air temperature were 27. 67, ± 2.98 °C, water temperature (28.37 ± 1.88), pH (7.85 ± 0.17), conductivity (44738.75 ± 6262.76 µS/cm), total dissolved solids (29236.71 ± 4273.30 mg/L), salinity (27.11 ± 3.91 ‰), alkalinity (126.99 ± 42.81 mg/L) and chloride (15056. 67 ± 2165.78 mg/L). Higher estimates were recorded in the dry than wet months for these characteristics. On the other hand, reducing values were recorded for acidity (2.34 ± 0.63 mg/L), total hardness (4711.98 ± 691.50 mg/L), phosphate (1.1 ± 0.78 mg/L), sulphate (2601.99 ± 447.04 mg/L) and nitrate (0.12 ± 0.06 mg/L). Values for total suspended solids and biological oxygen demand values were low (<1mg/L). Twenty-one species of phytoplankton were recorded. Diatoms recorded 80.92% and were the dominant group. Hemidiscus cuneiformis, Coscinodiscus centralis, Coscinodiscus lineatus, Coscinodiscus radiatus and Oscillatoria limosa were more frequently occurring species. Biddulphia sinensis and four species of Ceratium, were representatives of the dry season. The dry season also recorded comparatively higher individuals of phytoplankton than the wet season. Spirogyra sp. (green algae) appeared only in the wet season. Species abundance (N) was highest in December at Station 1 (13.15%) (dry season) and lowest in August (wet season) at Station 3 (2.96%). The physico-chemical factors and phytoplankton reflected a tropical unpolluted neritic oceanic environment.

Keywords: sea, physico-chemistry, lighthouse beach, microalgae

Procedia PDF Downloads 179

Authors: Dinda A. Utami, Muhammad N. Alfarizi

Abstract:

The purpose of this study was to determine the ability of zeolite catalyst for the trans- esterification reaction in biodiesel production from animal fat. The ability of the zeolite as a catalyst is determined by the structure and composition of the zeolite. An important factor that determines the properties of zeolites in catalysis includes adsorption capability to the compound of the reactants. Zeolites with a pore size of specific properties selectively adsorbing molecules. A molecule can be adsorbed by either the zeolite cavities if the size and shape of the molecule in accordance with the size and shape of the cavity in the zeolite. At this time, it is common to use homogeneous catalysts for biodiesel. We know these catalysts have some disadvantages in its use. Such as the difficulty of separation of the product with the catalyst, the generation of waste that is harmful to the environment due to residual catalysts can’t be reused, and the difficulty of handling and storage. But nowadays, solid catalyst developed technically to improve the efficiency of biodiesel production. In this case of study, we used trans-esterification process wherein the triglyceride is reacted with an alcohol with zeolite as a solid catalyst and it will produce biodiesel and glycerol as a byproduct. Development of solid catalyst seems to be the perfect solution to address the problems associated with homogeneous catalysts.

Keywords: biodiesel, animal fat, trans esterification, zeolite catalyst

Procedia PDF Downloads 253

Authors: Koosha Rezaei, Mehdi Moghri bidgoli, Mazyar Khakpour

Abstract:

Wood-plastic composites foam is one of the most used products were the industry today. In this study, composite foam polypropylene in the presence of different biofilers such as Spruce wood, wheat and rice husk as well as 3 different types toughening agents such as polyolefin elastomer, styrene butadiene styrene and styrene-ethylene butadiene styrene, and two types of cause blowing agents azodicarbonamide and sodium bicarbonate was prepared. For improving dispersion of biofilers, in the mixing process we used polypropylene coupling agent grafted with maleic anhydride. Due to the large number of variables, the statistical analysis of response surface to analyze the results of the impact test, tensile modulus and tensile strength and modeling were used. Co-rotating twine extruder was made composite melt mixing method and then to perform mechanical tests using injection molding, respectively.Images from electron microscopy showed cell sandwich structure in composite amply demonstrates.

Keywords: polypropylene, wood plastic composite foam, response surface analysis, morphology, mechanical properties

Procedia PDF Downloads 359

Authors: Maryam Taheri, Mehdi Jahanfar, Kenji Ogino

Abstract:

Fast drying traffic marking paint comprising a solvent-borne resin, a filler, a pigment and a solvent that is especially suitable for colder ambient (temperatures near freezing) applications, where waterborne traffic paint cannot be used. Acrylic resins based on methyl methacrylate, butyl acrylate, acrylic acid, and styrene were synthesized in different solvents using organic peroxide initiators such as peroxyester, peroxyketal, dialkylperoxide and azo. After polymerization, the molecular weight (Mw), polydispersity index= PDI (Mw/Mn), viscosity, total residual monomer and APHA color were evaluated and results of organic peroxide initiators (t- butyl and t-amyl derivatives) were also compared with the azo initiator. The Mw, PDI, viscosity, mass conversation and APHA color of resins with t-amyl derivatives of organic peroxide initiators are very proper. The results of the traffic marking paints test such as non-volatile matter, no- pick- up time, hiding power, resistance to wear and water resistance study that produced with these resins also confirm this.

Keywords: fast drying traffic marking paint, acrylic resin, organic peroxide initiator, peroxyester, peroxyketal, dialkylperoxide and azo initiator

Procedia PDF Downloads 200

Authors: Olumuyiwa Ojo, Masengo Ilunga

Abstract:

Artificial neural network (ANN) has broken the bounds of the convention programming, which is actually a function of garbage in garbage out by its ability to mimic the human brain. Its ability to adopt, adapt, adjust, evaluate, learn and recognize the relationship, behavior, and pattern of a series of data set administered to it, is tailored after the human reasoning and learning mechanism. Thus, the study aimed at modeling wastewater treatment process in order to accurately diagnose water control problems for effective treatment. For this study, a stage ANN model development and evaluation methodology were employed. The source data analysis stage involved a statistical analysis of the data used in modeling in the model development stage, candidate ANN architecture development and then evaluated using a historical data set. The model was developed using historical data obtained from Daspoort Wastewater Treatment plant South Africa. The resultant designed dimensions and model for wastewater treatment plant provided good results. Parameters considered were temperature, pH value, colour, turbidity, amount of solids and acidity. Others are total hardness, Ca hardness, Mg hardness, and chloride. This enables the ANN to handle and represent more complex problems that conventional programming is incapable of performing.

Keywords: ANN, artificial neural network, wastewater treatment, model, development

Procedia PDF Downloads 144

Authors: Rosdyana Mangir Irawan Kusuma, Wei-Chun Kao, Ho-Thi Trang, Yu-Yen Ou, Kai-Lung Hua

Abstract:

Stock market prediction is still a challenging problem because there are many factors that affect the stock market price such as company news and performance, industry performance, investor sentiment, social media sentiment, and economic factors. This work explores the predictability in the stock market using deep convolutional network and candlestick charts. The outcome is utilized to design a decision support framework that can be used by traders to provide suggested indications of future stock price direction. We perform this work using various types of neural networks like convolutional neural network, residual network and visual geometry group network. From stock market historical data, we converted it to candlestick charts. Finally, these candlestick charts will be feed as input for training a convolutional neural network model. This convolutional neural network model will help us to analyze the patterns inside the candlestick chart and predict the future movements of the stock market. The effectiveness of our method is evaluated in stock market prediction with promising results; 92.2% and 92.1 % accuracy for Taiwan and Indonesian stock market dataset respectively.

Keywords: candlestick chart, deep learning, neural network, stock market prediction

Procedia PDF Downloads 433

Authors: Olubusuyi Ayowole, Bashir Khoda

Abstract:

Green bioprinting, from the context of merging 3D bioprinting with microalgae cell organization, holds promise for industrial-scale optimization. This study employs spectrophotometric analysis to explore post-bioprinting cell growth density variation within hybrid hydrogel biomaterial scaffolds. Three hydrogel biomaterials—Alginic acid sodium salt (ALGINATE), Nanofibrillated Cellulose (NFC) – TEMPO, and CarboxyMethyl Cellulose (CMC)—are chosen for their scaffolding capabilities. Bioink development and analysis of their impact on cell proliferation and morphology are conducted. Chlorella microalgae cell growth within hydrogel compositions is probed using absorbance measurements, with additional assessment of shear thinning properties. Notably, NFC exhibits reduced shear thinning compared to CMC. Results reveal that while mono-hydrogel substrates with pronounced adhesion inhibit Chlorella cell proliferation, Alginate fosters increased cell concentration alongside a slight viscosity rise.

Keywords: green bioprinting, 3d bioprinting, microalgae cell, hybrid hydrogel scaffolds, spectrophotometric analysis, bioink development, shear thinning properties

Procedia PDF Downloads 18

Authors: Djalal Hamed

Abstract:

The aim of this paper is to perform, by mean of the finite volume method, a numerical solution of the transient natural convection in a narrow rectangular channel between two vertical parallel Material Testing Reactor (MTR)-type fuel plates, imposed under a heat flux with a cosine shape to determine the margin of the nuclear core power at which the natural convection cooling mode can ensure a safe core cooling, where the cladding temperature should not reach a specific safety limits (90 °C). For this purpose, a computer program is developed to determine the principal parameters related to the nuclear core safety, such as the temperature distribution in the fuel plate and in the coolant (light water) as a function of the reactor core power. Throughout the obtained results, we noticed that the core power should not reach 400 kW, to ensure a safe passive residual heat removing from the nuclear core by the upward natural convection cooling mode.

Keywords: buoyancy force, friction force, finite volume method, transient natural convection

Procedia PDF Downloads 190

Authors: Muhammad Atif Randhawa, Adnan Amjad

Abstract:

Assessment of insecticides used for growing vegetables in comparison with their safety status was the main purpose of this study. A total of 180 samples of okra (Abelmoschus esculentus L.) and brinjal (Solanum melongena L.) comprising 30 samples of each vegetable were collected from the peri-urban farming system of Multan, Faisalabad and Gujranwala. The mean value for imidacloprid residues found in brinjal (0.226 mg kg-1) and okra (0.176 mg kg-1) from Multan region were greater than the residues reported from Gujranwala and Faisalabad, showing excessive application of imidacloprid in Multan. Out of total 180 samples analysed for imidacloprid and acetamaprid residues, (90 samples for each of okra and brinjal), 104 (58%) and 117 (65%) samples contained detectable imidacloprid and acetamiprid residues, respectively. Whereas 10% and 15% samples exceeded their respective MRLs for imidacloprid and acetamiprid residues. Dietary intake assessment for imidacloprid and acetamiprid was calculated according to their MPI values 3.84 and 4.48 mg person-1day-1, respectively. The dietary intake assessment data revealed that although a reasonable proportion of samples exceeded the MRLs in studied areas but their consumption was found within safe limit in comparison to values obtained for MPI.

Keywords: Acceptable Daily Intake (ADI), insecticides, Maximum Residual Limits (MRLs), risk assessment, vegetables

Procedia PDF Downloads 311