Search results for: excess air ratio
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 4993

Search results for: excess air ratio

2593 Etude 3D Quantum Numerical Simulation of Performance in the HEMT

Authors: A. Boursali, A. Guen-Bouazza

Abstract:

We present a simulation of a HEMT (high electron mobility transistor) structure with and without a field plate. We extract the device characteristics through the analysis of DC, AC and high frequency regimes, as shown in this paper. This work demonstrates the optimal device with a gate length of 15 nm, InAlN/GaN heterostructure and field plate structure, making it superior to modern HEMTs when compared with otherwise equivalent devices. This improves the ability to bear the burden of the current density passes in the channel. We have demonstrated an excellent current density, as high as 2.05 A/m, a peak extrinsic transconductance of 0.59S/m at VDS=2 V, and cutting frequency cutoffs of 638 GHz in the first HEMT and 463 GHz for Field plate HEMT., maximum frequency of 1.7 THz, maximum efficiency of 73%, maximum breakdown voltage of 400 V, leakage current density IFuite=1 x 10-26 A, DIBL=33.52 mV/V and an ON/OFF current density ratio higher than 1 x 1010. These values were determined through the simulation by deriving genetic and Monte Carlo algorithms that optimize the design and the future of this technology.

Keywords: HEMT, silvaco, field plate, genetic algorithm, quantum

Procedia PDF Downloads 345
2592 Spatial Analysis and Determinants of Number of Antenatal Health Care Visit Among Pregnant Women in Ethiopia: Application of Spatial Multilevel Count Regression Models

Authors: Muluwerk Ayele Derebe

Abstract:

Background: Antenatal care (ANC) is an essential element in the continuum of reproductive health care for preventing preventable pregnancy-related morbidity and mortality. Objective: The aim of this study is to assess the spatial pattern and predictors of ANC visits in Ethiopia. Method: This study was done using Ethiopian Demographic and Health Survey data of 2016 among 7,174 pregnant women aged 15-49 years which was a nationwide community-based cross-sectional survey. Spatial analysis was done using Getis-Ord Gi* statistics to identify hot and cold spot areas of ANC visits. Multilevel glmmTMB packages adjusted for spatial effects were used in R software. Spatial multilevel count regression was conducted to identify predictors of antenatal care visits for pregnant women, and proportional change in variance was done to uncover the effect of individual and community-level factors of ANC visits. Results: The distribution of ANC visits was spatially clustered Moran’s I = 0.271, p<.0.001, ICC = 0.497, p<0.001). The highest spatial outlier areas of ANC visit was found in Amhara (South Wollo, Weast Gojjam, North Shewa), Oromo (west Arsi and East Harariga), Tigray (Central Tigray) and Benishangul-Gumuz (Asosa and Metekel) regions. The data was found with excess zeros (34.6%) and over-dispersed. The expected ANC visit of pregnant women with pregnancy complications was higher at 0.7868 [ARR= 2.1964, 95% CI: 1.8605, 2.5928, p-value <0.0001] compared to pregnant women who had no pregnancy complications. The expected ANC visit of a pregnant woman who lived in a rural area was 1.2254 times higher [ARR=3.4057, 95% CI: 2.1462, 5.4041, p-value <0.0001] as compared to a pregnant woman who lived in an urban. The study found dissimilar clusters with a low number of zero counts for a mean number of ANC visits surrounded by clusters with a higher number of counts of an average number of ANC visits when other variables held constant. Conclusion: This study found that the number of ANC visits in Ethiopia had a spatial pattern associated with socioeconomic, demographic, and geographic risk factors. Spatial clustering of ANC visits exists in all regions of Ethiopia. The predictor age of the mother, religion, mother’s education, husband’s education, mother's occupation, husband's occupation, signs of pregnancy complication, wealth index and marital status had a strong association with the number of ANC visits by each individual. At the community level, place of residence, region, age of the mother, sex of the household head, signs of pregnancy complications and distance to health facility factors had a strong association with the number of ANC visits.

Keywords: Ethiopia, ANC, spatial, multilevel, zero inflated Poisson

Procedia PDF Downloads 68
2591 Direct Conversion of Crude Oils into Petrochemicals under High Severity Conditions

Authors: Anaam H. Al-ShaikhAli, Mansour A. Al-Herz

Abstract:

The research leverages the proven HS-FCC technology to directly crack crude oils into petrochemical building blocks. Crude oils were subjected to an optimized hydro-processing process where metal contaminants and sulfur were reduced to an acceptable level for feeding the crudes into the HS-FCC technology. The hydro-processing is achieved through a fixed-bed reactor which is composed of 3 layers of catalysts. The crude oil is passed through a dementalization catalyst followed by a desulfurization catalyst and finally a de-aromatization catalyst. The hydroprocessing was conducted at an optimized liquid hourly space velocity (LHSV), temperature, and pressure for an optimal reduction of metals and sulfur from the crudes. The hydro-processed crudes were then fed into a micro activity testing (MAT) unit to simulate the HS-FCC technology. The catalytic cracking of crude oils was conducted over tailored catalyst formulations under an optimized catalyst/oil ratio and cracking temperature for optimal production of total light olefins.

Keywords: petrochemical, catalytic cracking, catalyst synthesis, HS-FCC technology

Procedia PDF Downloads 85
2590 Analysis of Electromechanical Torsional Vibration in Large-Power AC Drive System Based on Virtual Inertia Control

Authors: Jin Wang, Chunyi Zhu, Chongjian Li, Dapeng Zheng

Abstract:

A method based on virtual inertia for suppressing electromechanical torsional vibration of a large-power AC drive system is presented in this paper. The main drive system of the rolling mill is the research object, and a two-inertia elastic model is established to study the mechanism of electromechanical torsional vibration. The improvement is made based on the control of the load observer. The virtual inertia control ratio K is added to the speed forward channel, and the feedback loop adds 1-K to design virtual inertia control. The control method combines the advantages of the positive and negative feedback control of the load observer, can achieve the purpose of controlling the moment of inertia of the motor from the perspective of electrical control, and effectively suppress oscillation.

Keywords: electromechanical torsional vibration, large-power AC drive system, load observer, simulation design

Procedia PDF Downloads 119
2589 Influence of Major Axis on the Aerodynamic Characteristics of Elliptical Section

Authors: K. B. Rajasekarababu, J. Karthik, G. Vinayagamurthy

Abstract:

This paper is intended to explain the influence of major axis on aerodynamic characteristics of elliptical section. Many engineering applications such as off shore structures, bridge piers, civil structures and pipelines can be modelled as a circular cylinder but flow over complex bodies like, submarines, Elliptical wing, fuselage, missiles, and rotor blades, in which the parameters such as axis ratio can influence the flow characteristics of the wake and nature of separation. Influence of Major axis in Flow characteristics of elliptical sections are examined both experimentally and computationally in this study. For this research, four elliptical models with varying major axis [*AR=1, 4, 6, 10] are analysed. Experimental works have been conducted in a subsonic wind tunnel. Furthermore, flow characteristics on elliptical model are predicted from k-ε turbulence model using the commercial CFD packages by pressure based transient solver with Standard wall conditions.The analysis can be extended to estimation and comparison of Drag coefficient and Fatigue analysis of elliptical sections.

Keywords: elliptical section, major axis, aerodynamic characteristics, k-ε turbulence model

Procedia PDF Downloads 425
2588 Experimental Performance of Vertical Diffusion Stills Utilizing Folded Sheets for Water Desalination

Authors: M. Mortada, A. Seleem, M. El-Morsi, M. Younan

Abstract:

The present study introduces the folding technology to be utilized for the first time in vertical diffusion stills. This work represents a model of the distillation process by utilizing chevron pattern of folded structure. An experimental setup has been constructed, to investigate the performance of the folded sheets in the vertical effect diffusion still for a specific range of operating conditions. An experimental comparison between the folded type and the flat type sheets has been carried out. The folded pattern showed a higher performance and there is an increase in the condensate to feed ratio that ranges from 20-30 % through the operating hot plate temperature that ranges through 60-90°C. In addition, a parametric analysis of the system using Design of Experiments statistical technique, has been developed using the experimental results to determine the effect of operating conditions on the system's performance and the best operating conditions of the system has been evaluated.

Keywords: chevron pattern, fold structure, solar distillation, vertical diffusion still

Procedia PDF Downloads 456
2587 Confinement of Concrete Filled Steel Tubular Beams Using U-Links

Authors: Madiha Z. Ammari, Abdul Qader AlNajmi

Abstract:

A new system of U-links was used in this study to confine the concrete core in concrete-filled steel beams. This system aims to employ the separation expected between the steel tube and the concrete core in the compression side of the section in the plastic hinge zone. A total of six rectangular CFT beam specimens were tested under flexure using different D/t ratios and different diameters for the U-links to examine their effect on the flexural behavior of these beams. The ultimate flexural strength of the CFT beam specimens with U-links showed an increase of strength about 47% of the specimen with D/t ratio equals 37.5 above standard CFT beam specimen without U-links inside. State of concrete inside the tubes has shown no crushing of concrete when those beams were cut open at the location of the plastic hinge. Strain measurements revealed that the compressive strain of concrete was 5-6 times the concrete crushing strain.

Keywords: concrete-filled tubes, U-links, plated studies, beams, flexural strength, concrete, confinement

Procedia PDF Downloads 336
2586 Influence of Geometrical Parameters of a Wind Turbine on the Optimal Tip-Speed Ratio

Authors: Zdzislaw Piotr Kaminski, Miroslaw Wendeker, Zbigniew Czyz

Abstract:

The paper describes the geometric model, calculation algorithm and results of the CFD simulation of the airflow around a rotor in the vertical axis wind turbine (VAWT) with the ANSYS Fluent computational solver. The CFD method enables creating aerodynamic characteristics of forces acting on rotor working surfaces and determining parameters such as torque or power generated by the rotor assembly. The object of the research was a rotor whose construction is based on patent no.PL219985. The conducted tests enabled a mathematical model with a description of the generation of aerodynamic forces acting on each rotor blade. Additionally, this model was compared to the results of the wind tunnel tests. The analysis also focused on the influence of the blade angle on turbine power and the TSR. The research has shown that the turbine blade angle has a significant impact on the optimal value of the TSR.

Keywords: computational fluid dynamics, numerical analysis, renewable energy, wind turbine

Procedia PDF Downloads 145
2585 Falling and Rising of Solid Particles in Thermally Stratified Fluid

Authors: Govind Sharma, Bahni Ray

Abstract:

Ubiquitous nature of particle settling is governed by the presence of the surrounding fluid medium. Thermally stratified fluid alters the settling phenomenon of particles as well as their interactions. Direct numerical simulation (DNS) is carried out with an open-source library Immersed Boundary Adaptive Mesh Refinement (IBAMR) to quantify the fundamental mechanism based on Distributed Lagrangian Multiplier (DLM). The presence of background density gradient due to thermal stratification replaces the drafting-kissing-tumbling in a homogeneous fluid to drafting-kissing-separation behavior. Simulations are performed with a varying range of particle-fluid density ratios, and it is shown that the stratification effect on particle interactions varies with density ratio. It is observed that the combined role of buoyancy and inertia govern the physical mechanism of particle-particle interaction.

Keywords: direct numerical simulation, distributed lagrangian multiplier, rigidity constraint, sedimentation, stratification

Procedia PDF Downloads 131
2584 Shear Strengthening of Reinforced Concrete Deep Beam Using Fiber Reinforced Polymer Strips

Authors: Ruqaya H. Aljabery

Abstract:

Reinforced Concrete (RC) deep beams are one of the main critical structural elements in terms of safety since significant loads are carried in a short span. The shear capacity of these sections cannot be predicted accurately by the current design codes like ACI and EC2; thus, they must be investigated. In this research, non-linear behavior of RC deep beams strengthened in shear with Fiber Reinforced Polymer (FRP) strips, and the efficiency of FRP in terms of enhancing the shear capacity in RC deep beams are examined using Finite Element Analysis (FEA), which is conducted using the software ABAQUS. The effect of several parameters on the shear capacity of the RC deep beam are studied in this paper as well including the effect of the cross-sectional area of the FRP strip and the shear reinforcement area to the spacing ratio (As/S), and it was found that FRP enhances the shear capacity significantly and can be a substitution of steel stirrups resulting in a more economical design.

Keywords: Abaqus, concrete, deep beam, finite element analysis, FRP, shear strengthening, strut-and-tie

Procedia PDF Downloads 144
2583 Divalent Iron Oxidative Process for Degradation of Carbon and Nitrogen Based Pollutants from Dye Intermediate Industrial Wastewater

Authors: Nibedita Pani, Vishnu Tejani, T. S. Anantha Singh

Abstract:

Water pollution resulting from discharge of partial/not treated textile wastewater containing high carbon and nitrogen pollutants pose a huge threat to the environment, ecosystem, and human health. It is essential to remove carbon- and nitrogen-based organic pollutants more effectively from industrial wastewater before discharging. The present study focuses on removal of carbon-based pollutant in particular COD (chemical oxygen demand) and nitrogen-based pollutants, in particular, ammoniacal nitrogen by Fenton oxidation process using Fe²⁺ and H₂O₂ as reagents. The study was carried out with high strength wastewater containing initial COD 5632 mg/L and NH⁴⁺-N 1372 mg/L. The major operating condition like pH was varied between 1.0 to 4.0. The maximum degradation was obtained at pH 3.0 taking the molar ratio of Fe²⁺/H₂O₂ as 1:1. At this pH, the removal efficiencies of COD and ammoniacal nitrogen were found to be 77.27% and 74.9%, respectively. The Fenton process can be the best alternative for the simultaneous removal of COD and NH4+-N from industrial wastewater.

Keywords: ammoniacal nitrogen, COD, Fenton oxidation, industrial wastewater

Procedia PDF Downloads 195
2582 Research of the Three-Dimensional Visualization Geological Modeling of Mine Based on Surpac

Authors: Honggang Qu, Yong Xu, Rongmei Liu, Zhenji Gao, Bin Wang

Abstract:

Today's mining industry is advancing gradually toward digital and visual direction. The three-dimensional visualization geological modeling of mine is the digital characterization of mineral deposits and is one of the key technology of digital mining. Three-dimensional geological modeling is a technology that combines geological spatial information management, geological interpretation, geological spatial analysis and prediction, geostatistical analysis, entity content analysis and graphic visualization in a three-dimensional environment with computer technology and is used in geological analysis. In this paper, the three-dimensional geological modeling of an iron mine through the use of Surpac is constructed, and the weight difference of the estimation methods between the distance power inverse ratio method and ordinary kriging is studied, and the ore body volume and reserves are simulated and calculated by using these two methods. Compared with the actual mine reserves, its result is relatively accurate, so it provides scientific bases for mine resource assessment, reserve calculation, mining design and so on.

Keywords: three-dimensional geological modeling, geological database, geostatistics, block model

Procedia PDF Downloads 72
2581 Design and Simulation of Step Structure RF MEMS Switch for K Band Applications

Authors: G. K. S. Prakash, Rao K. Srinivasa

Abstract:

MEMS plays an important role in wide range of applications like biological, automobiles, military and communication engineering. This paper mainly investigates on capacitive shunt RF MEMS switch with low actuation voltage and low insertion losses. To trim the pull-in voltage, a step structure has introduced to trim air gap between the beam and the dielectric layer with that pull in voltage is trim to 2.9 V. The switching time of the proposed switch is 39.1μs, and capacitance ratio is 67. To get more isolation, we have used aluminum nitride as dielectric material instead of silicon nitride (Si₃N₄) and silicon dioxide (SiO₂) because aluminum nitride has high dielectric constant (εᵣ = 9.5) increases the OFF capacitance and eventually increases the isolation of the switch. The results show that the switch is ON state involves return loss (S₁₁) less than -25 dB up to 40 GHz and insertion loss (S₂₁) is more than -1 dB up to 35 GHz. In OFF state switch shows maximum isolation (S₂₁) of -38 dB occurs at a frequency of 25-27 GHz for K band applications.

Keywords: RF MEMS, actuation voltage, isolation loss, switches

Procedia PDF Downloads 357
2580 Image Compression Based on Regression SVM and Biorthogonal Wavelets

Authors: Zikiou Nadia, Lahdir Mourad, Ameur Soltane

Abstract:

In this paper, we propose an effective method for image compression based on SVM Regression (SVR), with three different kernels, and biorthogonal 2D Discrete Wavelet Transform. SVM regression could learn dependency from training data and compressed using fewer training points (support vectors) to represent the original data and eliminate the redundancy. Biorthogonal wavelet has been used to transform the image and the coefficients acquired are then trained with different kernels SVM (Gaussian, Polynomial, and Linear). Run-length and Arithmetic coders are used to encode the support vectors and its corresponding weights, obtained from the SVM regression. The peak signal noise ratio (PSNR) and their compression ratios of several test images, compressed with our algorithm, with different kernels are presented. Compared with other kernels, Gaussian kernel achieves better image quality. Experimental results show that the compression performance of our method gains much improvement.

Keywords: image compression, 2D discrete wavelet transform (DWT-2D), support vector regression (SVR), SVM Kernels, run-length, arithmetic coding

Procedia PDF Downloads 376
2579 Optimization of Machining Parameters in AlSi/10%AlN Metal Matrix Composite Material by TiN Coating Insert

Authors: Nurul Na'imy Wan, Mohamad Sazali Said, Jaharah Ab. Ghani, Rusli Othman

Abstract:

This paper presents the surface roughness of the aluminium silicon alloy (AlSi) matrix composite which has been reinforced with aluminium nitride (AlN). Experiments were conducted at various cutting speeds, feed rates, and depths of cut, according to a standard orthogonal array L27 of Taguchi method using TiN coating tool of insert. The signal-to-noise (S/N) ratio and analysis of variance are applied to study the characteristic performance of cutting speeds, feed rates and depths of cut in measuring the surface roughness during the milling operation. The surface roughness was observed using Mitutoyo Formtracer CS-500 and analyzed using the Taguchi method. From the Taguchi analysis, it was found that cutting speed of 230 m/min, feed rate of 0.4 mm/tooth, depth of cut of 0.3 mm were the optimum machining parameters using TiN coating insert.

Keywords: AlSi/AlN metal matrix composite (MMC), surface roughness, Taguchi method, machining parameters

Procedia PDF Downloads 425
2578 3D Quantum Simulation of a HEMT Device Performance

Authors: Z. Kourdi, B. Bouazza, M. Khaouani, A. Guen-Bouazza, Z. Djennati, A. Boursali

Abstract:

We present a simulation of a HEMT (high electron mobility transistor) structure with and without a field plate. We extract the device characteristics through the analysis of DC, AC and high frequency regimes, as shown in this paper. This work demonstrates the optimal device with a gate length of 15 nm, InAlN/GaN heterostructure and field plate structure, making it superior to modern HEMTs when compared with otherwise equivalent devices. This improves the ability to bear the burden of the current density passes in the channel. We have demonstrated an excellent current density, as high as 2.05 A/mm, a peak extrinsic transconductance of 590 mS/mm at VDS=2 V, and cutting frequency cutoffs of 638 GHz in the first HEMT and 463 GHz for Field plate HEMT., maximum frequency of 1.7 THz, maximum efficiency of 73%, maximum breakdown voltage of 400 V, DIBL=33.52 mV/V and an ON/OFF current density ratio higher than 1 x 1010. These values were determined through the simulation by deriving genetic and Monte Carlo algorithms that optimize the design and the future of this technology.

Keywords: HEMT, Silvaco, field plate, genetic algorithm, quantum

Procedia PDF Downloads 470
2577 Persian Pistachio Nut (Pistacia vera L.) Dehydration in Natural and Industrial Conditions

Authors: Hamid Tavakolipour, Mohsen Mokhtarian, Ahmad Kalbasi Ashtari

Abstract:

In this study, the effect of various drying methods (sun drying, shade drying and industrial drying) on final moisture content, shell splitting degree, shrinkage and color change were studied. Sun drying resulted higher degree of pistachio nuts shell splitting on pistachio nuts relative other drying methods. The ANOVA results showed that the different drying methods did not significantly effects on color change of dried pistachio nut. The results illustrated that pistachio nut dried by industrial drying had the lowest moisture content. After the end of drying process, initially, the experimental drying data were fitted with five famous drying models namely Newton, Page, Silva et al., Peleg and Henderson and Pabis. The results indicated that Peleg and Page models gave better results compared with other models to monitor the moisture ratio’s pistachio nut in industrial drying and open sun (or shade drying) methods, respectively.

Keywords: industrial drying, pistachio, quality properties, traditional drying

Procedia PDF Downloads 330
2576 A Novel Stress Instability Workability Criteria for Internal Ductile Failure in Steel Cold Heading Process

Authors: Amar Sabih, James Nemes

Abstract:

The occurrence of internal ductile failure within the Adiabatic Shear Band (ASB) in cold-headed products presents a significant barrier in the fast-expanding cold-heading (CH) industry. The presence of internal ductile failure in cold-headed products may lead to catastrophic fracture under tensile loads despite the ductile nature of the material causing expensive industrial recalls. Therefore, this paper presents a workability criterion that uses stress instability as an indicator to accurately reveal the locus of initiation of internal ductile failures. The concept of the instability criterion is to use the stress ratio at failure as a weighting function to indicate the initiation of ductile failure inside the ASBs. This paper presents a comprehensive experimental, metallurgical, and finite element simulation study to calculate the material constants used in this criterion.

Keywords: adiabatic shear band, workability criterion, ductile failure, stress instability

Procedia PDF Downloads 81
2575 Analysis of Joint Source Channel LDPC Coding for Correlated Sources Transmission over Noisy Channels

Authors: Marwa Ben Abdessalem, Amin Zribi, Ammar Bouallègue

Abstract:

In this paper, a Joint Source Channel coding scheme based on LDPC codes is investigated. We consider two concatenated LDPC codes, one allows to compress a correlated source and the second to protect it against channel degradations. The original information can be reconstructed at the receiver by a joint decoder, where the source decoder and the channel decoder run in parallel by transferring extrinsic information. We investigate the performance of the JSC LDPC code in terms of Bit-Error Rate (BER) in the case of transmission over an Additive White Gaussian Noise (AWGN) channel, and for different source and channel rate parameters. We emphasize how JSC LDPC presents a performance tradeoff depending on the channel state and on the source correlation. We show that, the JSC LDPC is an efficient solution for a relatively low Signal-to-Noise Ratio (SNR) channel, especially with highly correlated sources. Finally, a source-channel rate optimization has to be applied to guarantee the best JSC LDPC system performance for a given channel.

Keywords: AWGN channel, belief propagation, joint source channel coding, LDPC codes

Procedia PDF Downloads 354
2574 Extractive Desulfurization of Atmospheric Gasoil with N,N-Dimethylformamide

Authors: Kahina Bedda, Boudjema Hamada

Abstract:

Environmental regulations have been introduced in many countries around the world to reduce the sulfur content of diesel fuel to ultra low levels with the intention of lowering diesel engine’s harmful exhaust emissions and improving air quality. Removal of sulfur containing compounds from diesel feedstocks to produce ultra low sulfur diesel fuel by extraction with selective solvents has received increasing attention in recent years. This is because the sulfur extraction technologies compared to the hydrotreating processes could reduce the cost of desulfurization substantially since they do not demand hydrogen, and are carried out at atmospheric pressure. In this work, the desulfurization of distillate gasoil by liquid-liquid extraction with N, N-dimethylformamide was investigated. This fraction was recovered from a mixture of Hassi Messaoud crude oils and Hassi R'Mel gas-condensate in Algiers refinery. The sulfur content of this cut is 281 ppm. Experiments were performed in six-stage with a ratio of solvent:feed equal to 3:1. The effect of the extraction temperature was investigated in the interval 30 ÷ 110°C. At 110°C the yield of refined gas oil was 82% and its sulfur content was 69 ppm.

Keywords: desulfurization, gasoil, N, N-dimethylformamide, sulfur content

Procedia PDF Downloads 377
2573 Numerical Methods for Topological Optimization of Wooden Structural Elements

Authors: Daniela Tapusi, Adrian Andronic, Naomi Tufan, Ruxandra Erbașu, Ioana Teodorescu

Abstract:

The proposed theme of this article falls within the policy of reducing carbon emissions imposed by the ‘Green New Deal’ by replacing structural elements made of energy-intensive materials with ecological materials. In this sense, wood has many qualities (high strength/mass and stiffness/mass ratio, low specific gravity, recovery/recycling) that make it competitive with classic building materials. The topological optimization of the linear glulam elements, resulting from different types of analysis (Finite Element Method, simple regression on metamodels), tests on models or by Monte-Carlo simulation, leads to a material reduction of more than 10%. This article proposes a method of obtaining topologically optimized shapes for different types of glued laminated timber beams. The results obtained will constitute the database for AI training.

Keywords: timber, glued laminated timber, artificial-intelligence, environment, carbon emissions

Procedia PDF Downloads 24
2572 Determinants of Multidrug-Resistant Tuberculosis in Patients Who Underwent First-Line Treatment in Addis Ababa: A Case Control Study

Authors: Selamawit Hirpa, Girmay Medhin, Belaineh Girma, Muluken Melese, Alemayehu Mekonen, Pedro Suarez, Gobena Ameni

Abstract:

Worldwide, there were 650,000 multi-drug resistant tuberculosis (MDR-TB) cases in 2010. Ethiopia is 15th among the 27 MDR-TB high-burden countries. A case control study was conducted at St. Peter Hospital and five health centers in Addis Ababa. Cases were MDR-TB patients who were in treatment at St. Peter Hospital during the study period. Controls were patients who were on first-line anti-TB treatment and were registered as cured or having completed treatment in the period 9 April 2009– 28 February 2010, in five health centers. A structured interview questionnaire was used to assess factors that could potentially be associated with the occurrence of MDR-TB. Factors that were significantly associated with MDR-TB: drug side effects during first-line treatment (adjusted odds ratio (AOR): 4.5, 95% CI; 1.9 - 10.5); treatment not directly observed by a health worker (AOR = 11.7, 95% CI; 4–34.3); and retreatment with the Category II regimen (P = 0.000).

Keywords: adherence to TB treatment, MDR-TB, TB treatment, TB treatment regimens

Procedia PDF Downloads 492
2571 Effect of Zirconium Addition to Aluminum Grain Refined by Ti on its Resistance to Wear: A Three-Dimensional Approach

Authors: S. M. A. Al-Qawabah, A. I. O. Zaid

Abstract:

Aluminum and its alloys are versatile materials which are widely used in industrial and engineering applications due to their good and useful properties e.g. high strength to weight ratio, high thermal and electrical conductivities and good resistance to corrosion. However, against these favorable properties they have the disadvantage they solidifying large grain columnar structure which negatively affects their mechanical properties and surface quality. Aluminum alloys are normally grain refined by some alloying elements, such as Ti, Ti-B or Zr. In this paper, the effect of zirconium addition to Al grain refined by Ti after extrusion on its wear resistance is investigated under different loads and sliding speeds namely at 5,10 and 20 N loads and sliding speeds ranging from m/min. and m/min. the results are presented in three-dimensional wear mode. To the best the authors' knowledge, the wear of aluminum in 3-dimensions has never been tackled before. In this work, the wear resistance of by presenting the results of wear are presented and discussed on the time, load and speed plots.

Keywords: aluminum grain refined, addition of titanium, wear resistance, titanium

Procedia PDF Downloads 396
2570 Potential of Grass Silage as a Source of Nutrients in Poultry Production

Authors: Hamim Abbas, Jean Luc-Hornick, Isabelle Dufrasne

Abstract:

Feed costs constitute over 60% of total expenses in organic layer poultry production, with feed protein supply being a significant concern. Alfalfa-based dehydrated silage pellets are mainly diets composed of leaves (ABSP), which are non-conventional protein sources that could enhance profits by reducing feed costs and ensuring consistent availability. This experiment studied the effects on the performances of Novogen Brown light layers of a commercial control diet replaced with 10% ABSP. After a 21-day trial, this diet (ABSP) has improved the laying rate, yolk color of eggs, feed conversion rate, ω−3 (PUFAs) and ω−6/ω−3 ratio (P<0.05) while the body weight and egg weight were degraded with the substitution of the ABSP in the diet(P>0.05). The laying rate showed a tendency to increase (P=0.06). These findings suggest that ABSP can replace at least 10% of the feed in organic layer diets without compromising production parameters negatively.

Keywords: alfalfa, silage, pellet, organic layers

Procedia PDF Downloads 39
2569 Assessment of Highly Sensitive Dielectric Modulated GaN-FinFET for Label-Free Biosensing Applications

Authors: Ajay Kumar, Neha Gupta

Abstract:

This work presents the sensitivity assessment of Gallium Nitride (GaN) material-based FinFET by dielectric modulation in the nanocavity gap for label-free biosensing applications. The significant deflection is observed in the electrical characteristics such as drain current (ID), transconductance (gm), surface potential, energy band profile, electric field, sub-threshold slope (SS), and threshold voltage (Vth) in the presence of biomolecules owing to GaN material. Further, the device sensitivity is evaluated to identify the effectiveness of the proposed biosensor and its capability to detect the biomolecules with high precision or accuracy. Higher sensitivity is observed for Gelatin (k=12) in terms of on-current (SION), threshold voltage (SVth), and switching ratio (SSR) by 104.88%, 82.12%, and 119.73%, respectively. This work is performed using a powerful tool 3D Sentaurus TCAD using a well-calibrated structure. All the results pave the way for GaN-FinFET as a viable candidate for label-free dielectric modulated biosensor applications.

Keywords: biosensor, biomolecules, FinFET, sensitivity

Procedia PDF Downloads 195
2568 The Effect of Ni/Dolomite Catalyst for Production of Hydrogen from NaBH₄

Authors: Burcu Kiren, Alattin CAkan, Nezihe Ayas

Abstract:

Hydrogen will be arguably the best fuel in the future as it is the most abundant element in the universe. Hydrogen, as a fuel, is notably environmentally benign, sustainable and has high energy content compared to other sources of energy. It can be generated from both conventional and renewable sources. The hydrolysis reaction of metal hydrides provides an option for hydrogen production in the presence of a catalyst. In this study, Ni/dolomite catalyst was synthesized by the wet impregnation method for hydrogen production by hydrolysis reaction of sodium borohydride (NaBH4). Besides, the synthesized catalysts characterizations were examined by means of thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer –Emmett – Teller (BET) and scanning electron microscopy (SEM). The influence of reaction temperature (25-75 °C), reaction time (15-60 min.), amount of catalyst (50-250 mg) and active metal loading ratio (20,30,40 wt.%) were investigated. The catalyst prepared with 30 wt.% Ni was noted as the most suitable catalyst, achieving of 35.18% H₂ and hydrogen production rate of 19.23 mL/gcat.min at 25 °C at reaction conditions of 5 mL of 0.25 M NaOH and 100 mg NaBH₄, 100 mg Ni/dolomite.

Keywords: sodium borohydride, hydrolysis, catalyst, Ni/dolomite, hydrogen

Procedia PDF Downloads 155
2567 Statistical Channel Modeling for Multiple-Input-Multiple-Output Communication System

Authors: M. I. Youssef, A. E. Emam, M. Abd Elghany

Abstract:

The performance of wireless communication systems is affected mainly by the environment of its associated channel, which is characterized by dynamic and unpredictable behavior. In this paper, different statistical earth-satellite channel models are studied with emphasize on two main models, first is the Rice-Log normal model, due to its representation for the environment including shadowing and multi-path components that affect the propagated signal along its path, and a three-state model that take into account different fading conditions (clear area, moderate shadow and heavy shadowing). The provided models are based on AWGN, Rician, Rayleigh, and log-normal distributions were their Probability Density Functions (PDFs) are presented. The transmission system Bit Error Rate (BER), Peak-Average-Power Ratio (PAPR), and the channel capacity vs. fading models are measured and analyzed. These simulations are implemented using MATLAB tool, and the results had shown the performance of transmission system over different channel models.

Keywords: fading channels, MIMO communication, RNS scheme, statistical modeling

Procedia PDF Downloads 142
2566 Identifying Network Subgraph-Associated Essential Genes in Molecular Networks

Authors: Efendi Zaenudin, Chien-Hung Huang, Ka-Lok Ng

Abstract:

Essential genes play an important role in the survival of an organism. It has been shown that cancer-associated essential genes are genes necessary for cancer cell proliferation, where these genes are potential therapeutic targets. Also, it was demonstrated that mutations of the cancer-associated essential genes give rise to the resistance of immunotherapy for patients with tumors. In the present study, we focus on studying the biological effects of the essential genes from a network perspective. We hypothesize that one can analyze a biological molecular network by decomposing it into both three-node and four-node digraphs (subgraphs). These network subgraphs encode the regulatory interaction information among the network’s genetic elements. In this study, the frequency of occurrence of the subgraph-associated essential genes in a molecular network was quantified by using the statistical parameter, odds ratio. Biological effects of subgraph-associated essential genes are discussed. In summary, the subgraph approach provides a systematic method for analyzing molecular networks and it can capture useful biological information for biomedical research.

Keywords: biological molecular networks, essential genes, graph theory, network subgraphs

Procedia PDF Downloads 152
2565 Mechanical Properties of Class F Fly Ash Blended Concrete Incorporation with Natural Admixture

Authors: T. S. Ramesh Babu, D. Neeraja

Abstract:

This research work revealed that effect of Natural admixture (NAD) on Conventional Concrete (CC) and Class F Fly Ash(FA) blended concrete. Broiler hen egg white albumen and yellow yolk were used as Natural Admixture. Cement was replaced by Class F fly ash at various levels of 0%, 25%, 35%, 45% and 55% by its mass and NAD was added to concrete at different replacement dosages of 0%, 0.25%, 0.5%, 0.75% and 1.00% by its volume to water content and liquid to binder ratio was maintained at 0.5. For all replacement levels of FA and NAD, the mechanical properties viz unit weight, compressive strength, splitting tensile strength and modulus of elasticity of CC and Class F fly ash (FA) were studied at 7, 28, 56 and 112 days. From the results, it was concluded that 0.25% of NAD dosage was considered as optimum dosage for both CC and class F fly ash blended concrete. The studies revealed that 35% Class F fly ash blended concrete mix is concluded as optimum mix and 55% Class F fly ash blended concrete mix is concluded as economical mix with 0.25% NAD dosage.

Keywords: Class F fly ash, compressive strength, modulus of elasticity, natural admixture, splitting tensile strength, unit weight

Procedia PDF Downloads 286
2564 Sonochemical Zinc Oxide and Layered Hydroxy Zinc Acetate Synthesis in Fenton-Like Reactions

Authors: Durata Haciu, Ozgur Birer

Abstract:

Zinc acetate solution is sonicated at high power in water and in ethanol in the absence and presence of various peroxides. In the absence of peroxides, the products are zinc oxide and layered hydroxy zinc acetate in water and in ethanol, respectively. Layered basic zinc acetate are prepared for the first time using sonochemical methods. The addition of peroxides alters the reaction mechanisms. In water, insoluble peroxides produce zinc oxides while the water soluble peroxide, i.e.hydrogen peroxide, completely destroyed the structure and casted a doubt on the accepted peroxide initiated mechanism of reactions. In ethanol,peroxide addition caused the reaction mechanism to change and some oxide formation is observed. The reaction mechanism is sensitive to water/ethanol amounts as well as the peroxide to zinc ion mole ratio.Thin zinc oxide wafers (ca. 30 nm) with band gaps of 3.24 eV were obtained.

Keywords: ultrasound, zinc oxide, hydroxy zinc acetate, fenton, peroxide initiation

Procedia PDF Downloads 288