Search results for: high step-up ratio

Authors: Biswarup Mukherjee, Aniruddha Ghoshal

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In this paper, we propose a new technique for implementing a low power high speed full adder using 8 transistors. Full adder circuits are used comprehensively in Application Specific Integrated Circuits (ASICs). Thus it is desirable to have high speed operation for the sub components. The explored method of implementation achieves a high speed low power design for the full adder. Simulated results indicate the superior performance of the proposed technique over conventional 28 transistor CMOS full adder. Detailed comparison of simulated results for the conventional and present method of implementation is presented.

Keywords: high speed low power full adder, 2-T MUX, 3-T XOR, 8-T FA, pass transistor logic, CMOS (complementary metal oxide semiconductor)

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Authors: Xize Dai, Jian Hao, Claus Leth Bak, Gian Carlo Montanari, Huai Wang

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Printed Circuit Board (PCB) is a critical component applicable to power electronics systems, especially for high-voltage applications involving several high-voltage and high-frequency SiC/GaN devices. The insulation system of PCB is facing more challenges from high-voltage and high-frequency stress that can alter the dielectric properties. Dielectric properties of the PCB insulation system also determine the electrical field distribution that correlates with intrinsic and extrinsic aging mechanisms. Hence, investigating the dielectric properties in the frequency domain of the PCB insulation system is a must. The paper presents the frequency-dependent, temperature-dependent, and voltage-dependent dielectric properties, permittivity, conductivity, and dielectric loss tangents of PCB insulation systems. The dielectric properties mechanisms associated with frequency, temperature, and voltage are revealed from the design perspective. It can be concluded that the dielectric properties of PCB in the frequency domain show a strong dependence on voltage, frequency, and temperature. The voltage-, frequency-, and temperature-dependent dielectric properties are associated with intrinsic conduction behavior and polarization patterns from the perspective of dielectric theory. The results may provide some reference for the PCB insulation system design in high voltage, high frequency, and high-temperature power electronics applications.

Keywords: electrical insulation system, dielectric properties, high voltage and frequency, printed circuit board

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Authors: R. M. EL-Sharkawy, L. S. Nasrat, K. B. Ewiss

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This work presents a study of flashover voltage for outdoor polyester and composite insulators under dry, ultra-violet and contaminated conditions. Cylindrical of polyester composite samples (with different lengths) have been prepared after incorporated with different concentration of inorganic filler e.g. Magnesium Hydroxide [Mg(OH)2] to improve the electrical and thermal properties in addition to maximize surface flashover voltage and decrease tracking phenomena. Results showed that flashover voltage reaches to 46 kV for samples without filler and 52.6 kV for samples containing 40% of [Mg(OH)2] filler in dry condition. A comparison between different concentrations of filler under various environmental conditions (dry and contaminated conditions) showed higher flashover voltage values for samples containing filler with ratio 40% [Mg(OH)2] and length 3cm than that of samples containing filler [Mg(OH)2] with ratios 20%, 30% and lengths 0.5cm, 1cm, 2cm and 2.5cm. Flashover voltage decreases by adding [Mg(OH)2] filler for polyester samples under ultra-violet condition; as the ratio of filler increases, the value of flashover voltage decreases Also, in this study, the effect of thermal performance with respect to surface of the sample under test have been investigated in details.

Keywords: flashover voltage, filler, polymers, ultra-violet radiation

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Authors: Iñaki Milton-Laskibar, Leixuri Aguirre, Maria P. Portillo

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Introduction: Energy restriction is an effective approach in preventing liver steatosis. However, due to social and economic reasons among others, compliance with this treatment protocol is often very poor, especially in the long term. Resveratrol, a natural polyphenolic compound that belongs to stilbene group, has been widely reported to imitate the effects of energy restriction. Objective: To analyze the effects of resveratrol under normoenergetic feeding conditions and under a mild energy restriction on liver fat accumulation and hepatic fatty acid oxidation. Methods: 36 male six-week-old rats were fed a high-fat high-sucrose diet for 6 weeks in order to induce steatosis. Then, rats were divided into four groups and fed a standard diet for 6 additional weeks: control group (C), resveratrol group (RSV, resveratrol 30 mg/kg/d), restricted group (R, 15 % energy restriction) and combined group (RR, 15 % energy restriction and resveratrol 30 mg/kg/d). Liver triacylglycerols (TG) and total cholesterol contents were measured by using commercial kits. Carnitine palmitoyl transferase 1a (CPT 1a) and citrate synthase (CS) activities were measured spectrophotometrically. TFAM (mitochondrial transcription factor A) and peroxisome proliferator-activator receptor alpha (PPARα) protein contents, as well as the ratio acetylated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α)/Total PGC1α were analyzed by Western blot. Statistical analysis was performed by using one way ANOVA and Newman-Keuls as post-hoc test. Results: No differences were observed among the four groups regarding liver weight and cholesterol content, but the three treated groups showed reduced TG when compared to the control group, being the restricted groups the ones showing the lowest values (with no differences between them). Higher CPT 1a and CS activities were observed in the groups supplemented with resveratrol (RSV and RR), with no difference between them. The acetylated PGC1α /total PGC1α ratio was lower in the treated groups (RSV, R and RR) than in the control group, with no differences among them. As far as TFAM protein expression is concerned, only the RR group reached a higher value. Finally, no changes were observed in PPARα protein expression. Conclusions: Resveratrol administration is an effective intervention for liver triacylglycerol content reduction, but a mild energy restriction is even more effective. The mechanisms of action of these two strategies are different. Thus resveratrol, but not energy restriction, seems to act by increasing fatty acid oxidation, although mitochondriogenesis seems not to be induced. When both treatments (resveratrol administration and a mild energy restriction) were combined, no additive or synergic effects were appreciated. Acknowledgements: MINECO-FEDER (AGL2015-65719-R), Basque Government (IT-572-13), University of the Basque Country (ELDUNANOTEK UFI11/32), Institut of Health Carlos III (CIBERobn). Iñaki Milton is a fellowship from the Basque Government.

Keywords: energy restriction, fat, liver, oxidation, resveratrol

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Authors: Lebogang L. R. Mphahlele, Bruce B. Sithole

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Chicken meat is the highest consumed meat in south Africa, with a per capita consumption of >33 kg yearly. Hence, South Africa produces over 250 million kg of waste chicken feathers each year, the majority of which is landfilled or incinerated. The discarded feathers have caused environmental pollution and natural protein resource waste. Therefore, the valorisation of waste chicken feathers is measured as a more environmentally friendly and cost-effective treatment. Feather contains 91% protein, the main component being beta-keratin, a fibrous and insoluble structural protein extensively cross linked by disulfide bonds. Keratin is usually converted it into nanofibers via electrospinning for a variety of applications. keratin nanofiber composites have many potential biomedical applications for their attractive features, such as high surface-to-volume ratio and very high porosity. The application of nanofibers in the biomedical wound dressing requires antimicrobial properties for materials. One approach is incorporating inorganic nanoparticles, among which silver nanoparticles played an important alternative antibacterial agent and have been studied against many types of microbes. The objective of this study is to combine synthetic polymer, chicken feather keratin, and antibacterial nanoparticles to develop novel electrospun antibacterial nanofibrous composites for possible wound dressing application. Furthermore, this study will converting a two-dimensional electrospun nanofiber membrane to three-dimensional fiber networks that resemble the structure of the extracellular matrix (ECM)

Keywords: chicken feather keratin, nanofibers, nanoparticles, nanocomposites, wound dressing

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Authors: J. O. Idoko, C. N. Michael, T. O. Fasuan

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This study investigated the effects of cooking time, seed-to-water ratio and soaking time on proximate and functional properties of African walnut seed using Box-Behnken design and Response Surface Methodology (BBD-RSM) with a view to increase its utilization in the food industry. African walnut seeds were sorted washed, soaked, cooked, dehulled, sliced, dried and milled. Proximate analysis and functional properties of the samples were evaluated using standard procedures. Data obtained were analyzed using descriptive and inferential statistics. Quadratic models were obtained to predict the proximate and functional qualities as a function of cooking time, seed-to-water ratio and soaking time. The results showed that the crude protein ranged between 11.80% and 23.50%, moisture content ranged between 1.00% and 4.66%, ash content ranged between 3.35% and 5.25%, crude fibre ranged from 0.10% to 7.25% and carbohydrate ranged from 1.22% to 29.35%. The functional properties showed that soluble protein ranged from 16.26% to 42.96%, viscosity ranged from 23.43 mPas to 57 mPas, emulsifying capacity ranged from 17.14% to 39.43% and water absorption capacity ranged from 232% to 297%. An increase in the volume of water used during cooking resulted in loss of water soluble protein through leaching, the length of soaking time and the moisture content of the dried product are inversely related, ash content is inversely related to the cooking time and amount of water used, extraction of fat is enhanced by increase in soaking time while increase in cooking and soaking times result into decrease in fibre content. The results obtained indicated that African walnut could be used in several food formulations as protein supplement and binder.

Keywords: African walnut, functional properties, proximate analysis, response surface methodology

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Authors: E. Happ, A. Albert Tóth

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The aim of the research is to investigate the forms of the demands of leisure tourism in a West-Hungarian industrial city, Győr. Today, Győr is still a traditional industrial city, its industry is mainly based on vehicle industry, but the role of tourism is increasing in the life of the city as well. Because of the industrial nature and the strong economy of the city, the ratio of business tourists is high. It can be stated that MICE tourism is dominating in Győr. Developments of the last decade can help the city with new tourism products to increase the leisure tourism. The new types of tourism – besides business tourism – can help the providers to increase the occupancy rates and the demand at the weekends. The research demonstrates the theoretical background of the topic, and it shows the present situation of the tourism in Győr with secondary data. The secondary research contains statistical data from the Hungarian Statistical Office and the city council, and it is based on the providers’ data. The next part of the paper shows the potential types of leisure tourism with the help of primary research. The primary research contains the results of an online questionnaire with a sample of 1000 potential customers. It is completed with 10 in-depth interviews with tourism experts, who explained their opinions about the opportunities of leisure tourism in Győr from the providers’ side. The online questionnaire was filled out in spring 2017 by customers, who have already stayed in Győr or plan to visit the city. At the same time in-depth interviews were made with hotel managers, head of touristic institutions and employees at the council. Based on the research it can be stated that the touristic supply of Győr allows the increase of the leisure tourism ratio in the city. Primarily, the cultural and health tourism show potential development, but the supply side of touristic services can be developed in order to increase the number of guest nights. The tourism marketing needs to be strengthened in the city, and a distinctive marketing activity - from other cities - is needed as well. To conclude, although Győr is an industrial city, it has a transforming industrial part, and tourism is also strongly present in its economy. Besides the leading role of business tourism, different types of leisure tourism have the opportunity to take place in the city.

Keywords: business tourism, Győr, industrial city, leisure tourism, touristic demand

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Authors: Hyungoo Kang, Jinkoo Kim

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This study investigated the determination of the optimal location and friction force of friction dampers to effectively reduce the seismic response of a reinforced concrete structure designed without considering seismic load. To this end, the genetic algorithm process was applied and the results were compared with those obtained by simplified methods such as distribution of dampers based on the story shear or the inter-story drift ratio. The seismic performance of the model structure with optimally positioned friction dampers was evaluated by nonlinear static and dynamic analyses. The analysis results showed that compared with the system without friction dampers, the maximum roof displacement and the inter-story drift ratio were reduced by about 30% and 40%, respectively. After installation of the dampers about 70% of the earthquake input energy was dissipated by the dampers and the energy dissipated in the structural elements was reduced by about 50%. In comparison with the simplified methods of installation, the genetic algorithm provided more efficient solutions for seismic retrofit of the model structure.

Keywords: friction dampers, genetic algorithm, optimal design, RC buildings

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Authors: Chen-Chang Lee, Po-Chou Chen, Jo-Chi Jao, Chun-Chung Lui, Leung-Chit Tsang, Lain-Chyr Hwang

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Fetal Magnetic Resonance Imaging (MRI) is a challenge task because the fetal movements could cause motion artifact in MR images. The remedy to overcome this problem is to use fast scanning pulse sequences. The Single-Shot Fast Spin-Echo (SSFSE) T2-weighted imaging technique is routinely performed and often used as a gold standard in clinical examinations. Fast spoiled gradient-echo (FSPGR) T1-Weighted Imaging (T1WI) is often used to identify fat, calcification and hemorrhage. Fast Imaging Employing Steady-State Acquisition (FIESTA) is commonly used to identify fetal structures as well as the heart and vessels. The contrast of FIESTA image is related to T1/T2 and is different from that of SSFSE. The advantages and disadvantages of these two scanning sequences for fetal imaging have not been clearly demonstrated yet. This study aimed to compare these three rapid MRI techniques (SSFSE, FIESTA, and FSPGR) for fetal MRI examinations. The image qualities and influencing factors among these three techniques were explored. A 1.5T GE Discovery 450 clinical MR scanner with an eight-channel high-resolution abdominal coil was used in this study. Twenty-five pregnant women were recruited to enroll fetal MRI examination with SSFSE, FIESTA and FSPGR scanning. Multi-oriented and multi-slice images were acquired. Afterwards, MR images were interpreted and scored by two senior radiologists. The results showed that both SSFSE and T2W-FIESTA can provide good image quality among these three rapid imaging techniques. Vessel signals on FIESTA images are higher than those on SSFSE images. The Specific Absorption Rate (SAR) of FIESTA is lower than that of the others two techniques, but it is prone to cause banding artifacts. FSPGR-T1WI renders lower Signal-to-Noise Ratio (SNR) because it severely suffers from the impact of maternal and fetal movements. The scan times for these three scanning sequences were 25 sec (T2W-SSFSE), 20 sec (FIESTA) and 18 sec (FSPGR). In conclusion, all these three rapid MR scanning sequences can produce high contrast and high spatial resolution images. The scan time can be shortened by incorporating parallel imaging techniques so that the motion artifacts caused by fetal movements can be reduced. Having good understanding of the characteristics of these three rapid MRI techniques is helpful for technologists to obtain reproducible fetal anatomy images with high quality for prenatal diagnosis.

Keywords: fetal MRI, FIESTA, FSPGR, motion artifact, SSFSE

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Authors: Conceição, J. F. M., Rebelo H., Corneliu C., Pereira L.

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This research analyses the response of two distinct types of concrete blocks, each possessing an approximate unconfined compressive strength of 30MPa, when exposed to high-velocity impacts produced by an Explosively Formed Penetrator (EFP) traveling at an initial velocity of 1200 m/s. Given the scarcity of studies exploring high-velocity impacts on concrete, the primary aim of this research is to scrutinize how concrete behaves under high-speed impacts, ultimately contributing valuable insights to the development of protective structures. To achieve this objective, a comprehensive numerical analysis was carried out in LS-DYNA to delve into the fracture mechanisms inherent in concrete under such extreme conditions. Subsequently, the obtained numerical outcomes were compared and validated through eight experimental field tests. The methodology employed involved a robust combination of numerical simulations and real-world experiments, ensuring a comprehensive understanding of concrete behavior in scenarios involving rapid, high-energy impacts.

Keywords: high-velocity, impact, numerical analysis, experimental tests, concrete

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Authors: Linyu Wang, Liguo Qiao, Jianhong Xiang, Hao Xu

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In semantic communication, the existing joint Source Channel coding (JSCC) wireless communication system without pilot has unstable transmission performance and can not effectively capture the global information and location information of images. In this paper, a pilot-free image transmission system of joint source channel based on multi-level semantic information (Multi-level JSCC) is proposed. The transmitter of the system is composed of two networks. The feature extraction network is used to extract the high-level semantic features of the image, compress the information transmitted by the image, and improve the bandwidth utilization. Feature retention network is used to preserve low-level semantic features and image details to improve communication quality. The receiver also is composed of two networks. The received high-level semantic features are fused with the low-level semantic features after feature enhancement network in the same dimension, and then the image dimension is restored through feature recovery network, and the image location information is effectively used for image reconstruction. This paper verifies that the proposed multi-level JSCC algorithm can effectively transmit and recover image information in both AWGN channel and Rayleigh fading channel, and the peak signal-to-noise ratio (PSNR) is improved by 1~2dB compared with other algorithms under the same simulation conditions.

Keywords: deep learning, JSCC, pilot-free picture transmission, multilevel semantic information, robustness

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Authors: M. Yildirim, A. S. Kipcak, F. T. Senberber, M. O. Asensio, E. M. Derun, S. Piskin

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Potassium borates, which are widely used in welding and metal refining industry, as a lubricating oil additive, cement additive, fiberglass additive and insulation compound, are one of the important groups of borate minerals. In this study the production of a potassium borate mineral via hydrothermal method is aimed. The potassium source of potassium nitrate (KNO3) was used along with a sodium source of sodium hydroxide (NaOH) and boron source of boric acid (H3BO3). The constant parameters of reaction temperature and reaction time were determined as 80°C and 1 h, respectively. The molar ratios of 1:1:3 (as KNO3:NaOH:H3BO3), 1:1:4, 1:1:5, 1:1:6 and 1:1:7 were used. Following the synthesis the identifications of the produced products were conducted by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). The results of the experiments and analysis showed in the ratio of 1:1:6, the Santite mineral with powder diffraction file number (pdf no.) of 01-072-1688, which is known as potassium pentaborate (KB5O8•4H2O) was synthesized as best.

Keywords: hydrothermal synthesis, potassium borate, potassium nitrate, santite

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Authors: O. P. Rahi, Manoj Kumar

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Power transformers are essential and expensive equipments in electrical power system. Dissolved gas analysis (DGA) is one of the most useful techniques to detect incipient faults in power transformers. However, the identification of the faulted location by conventional method is not always an easy task due to variability of gas data and operational variables. In this paper, an extension theory based power transformer fault diagnosis method is presented. Extension theory tries to solve contradictions and incompatibility problems. This paper first briefly introduces the basic concept of matter element theory, establishes the matter element models for three-ratio method, and then briefly discusses extension set theory. Detailed analysis is carried out on the extended relation function (ERF) adopted in this paper for transformer fault diagnosis. The detailed diagnosing steps are offered. Simulation proves that the proposed method can overcome the drawbacks of the conventional three-ratio method, such as no matching and failure to diagnose multi-fault. It enhances diagnosing accuracy.

Keywords: DGA, extension theory, ERF, fault diagnosis power transformers, fault diagnosis, fuzzy logic

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Authors: Muhammed Saeed Rasheed

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Knowledge of the zinc and phytic acid (PA) concentrations of staple cereal crops are essential when evaluating the nutritional health of national and regional populations. In the present study, a total of 120 farmers’ fields in Iraqi Kurdistan were surveyed for zinc status in soil and wheat grain samples; wheat is the staple carbohydrate source in the region. Soils were analysed for total concentrations of phosphorus (PT) and zinc (ZnT), available P (POlsen) and Zn (ZnDTPA) and for pH. Average values (mg kg-1) ranged between 403-3740 (PT), 42.0-203 (ZnT), 2.13-28.1 (POlsen) and 0.14-5.23 (ZnDTPA); pH was in the range 7.46-8.67. The concentrations of Zn, PA/Zn molar ratio and estimated Zn bioavailability were also determined in wheat grain. The ranges of Zn and PA concentrations (mg kg⁻¹) were 12.3-63.2 and 5400 – 9300, respectively, giving a PA/Zn molar ratio of 15.7-30.6. A trivariate model was used to estimate intake of bioaccessible Zn, employing the following parameter values: (i) maximum Zn absorption = 0.09 (AMAX), (ii) equilibrium dissociation constant of zinc-receptor binding reaction = 0.680 (KP), and (iii) equilibrium dissociation constant of Zn-PA binding reaction = 0.033 (KR). In the model, total daily absorbed Zn (TAZ) (mg d⁻¹) as a function of total daily nutritional PA (mmole d⁻¹) and total daily nutritional Zn (mmole Zn d⁻¹) was estimated assuming an average wheat flour consumption of 300 g day⁻¹ in the region. Consideration of the PA and Zn intake suggest only 21.5±2.9% of grain Zn is bioavailable so that the effective Zn intake from wheat is only 1.84-2.63 mg d-1 for the local population. Overall results suggest available dietary Zn is below recommended levels (11 mg d⁻¹), partly due to low uptake by wheat but also due to the presence of large concentrations of PA in wheat grains. A crop breeding program combined with enhanced agronomic management methods is needed to enhance both Zn uptake and bioavailability in grains of cultivated wheat types.

Keywords: phosphorus, zinc, phytic acid, phytic acid to zinc molar ratio, zinc bioavailability

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Authors: Reza Ziaie Moayed, Javad Shamsi Soosahab

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The bearing capacity of shallow foundations is one of the interesting subjects in geotechnical engineering. Soil improvement by geosynthetic reinforcements is a modern method used in different projects to improve the bearing capacity of foundations. In this paper, numerical study is adopted to investigate the effect of geogrid soil reinforcement on shallow foundation behavior resting on anisotropic sand with using a finite element limit analysis software. The effect of the ratio of horizontal elastic modulus with respect to vertical elastic modulus (EH/EV) investigates on bearing capacity of foundations. The results illustrate that in sandy soils, the anisotropic ratio of elastic modulus (EH/EV) has notable effect on bearing capacity of shallow foundations. Also, based on the results of this study, it was concluded that geogrid could be used as soil reinforcement elements to improve the bearing of sandy soils and reduce its settlement possible remarkably.

Keywords: shallow foundations, bearing capacity, numerical study, soil anisotropy, geogrid

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Authors: Radia Guerza

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Tutoring at the Algerian University has been an issue of great controversy and debate. Henceforth, the current paper is an attempt to shed light on the issue of tutoring at Algerian University. It aims to set a plan for tutoring that might meet the student's needs and challenges. It endeavors to explore the following query: “what is the role of tutoring in the Algerian university between “The CAN DO” and “The HAVE TO”? To equate with the addressed research question, an exploratory small-scale study has been carried out at Batna 2 University using questionnaires and interviews with fifty (50) teachers. Results indicate that Algerian University is still lagging behind because of the huge lack of infrastructure means, human resources, and even pedagogical resources. In addition, the majority of our teachers are reluctant to adhere to the tutorial policy due to the lack of incentives; next to that, the increasing yearly number of students and students high ratio would hardly permit any tutoring sessions. Finally, this paper is the first attempt, to our best knowledge, towards raising the awareness of our institution, staff members, teachers, and students towards the importance of tutoring and how to adopt it.

Keywords: attitudes, higher education, perceptions, tutoring

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Authors: N. V. Kazmiruk, Y. R. Nartsissov

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Phosphate activated glutaminase (GA, E.C. 3.5.1.2) plays a key role in glutamine/glutamate homeostasis in mammalian brain, catalyzing the hydrolytic deamidation of glutamine to glutamate and ammonium ions. GA is mainly localized in mitochondria, where it has the catalytically active form on the inner mitochondrial membrane (IMM) and the other soluble form, which is supposed to be dormant. At present time, the exact localization of the membrane glutaminase active site remains a controversial and an unresolved issue. The first hypothesis called c-side localization suggests that the catalytic site of GA faces the inter-membrane space and products of the deamidation reaction have immediate access to cytosolic metabolism. According to the alternative m-side localization hypothesis, GA orients to the matrix, making glutamate and ammonium available for the tricarboxylic acid cycle metabolism in mitochondria directly. In our study, we used a multi-compartment kinetic approach to simulate metabolism of glutamate and glutamine in the astrocytic cytosol and mitochondria. We used physiologically important ratio between the concentrations of glutamine inside the matrix of mitochondria [Glnₘᵢₜ] and glutamine in the cytosol [Glncyt] as a marker for precise functioning of the system. Since this ratio directly depends on the mitochondrial glutamine carrier (MGC) flow parameters, key observation was to investigate the dependence of the [Glnmit]/[Glncyt] ratio on the maximal velocity of MGC at different initial concentrations of mitochondrial glutamate. Another important task was to observe the similar dependence at different inhibition constants of the soluble GA. The simulation results confirmed the experimental c-side localization hypothesis, in which the glutaminase active site faces the outer surface of the IMM. Moreover, in the case of such localization of the enzyme, a 3-fold decrease in ammonium production was predicted.

Keywords: glutamate metabolism, glutaminase, kinetic approach, mitochondrial membrane, multi-compartment modeling

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Authors: Kwarciak-Kozlowska A., Slawik-Dembiczak L., Galwa-Widera M.

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Complex and variable during operation of the landfill leachate composition prevents the use of a single universal method of their purification. Due to the presence of difficult biodegradable these substances in the wastewater, cleaning of them often requires the use of biological methods (activated sludge or anaerobic digestion), also often supporting by physicochemical processes. Currently, more attention is paid to the development of unconventional methods of disposal of sewage m.in ultleniania advanced methods including the use of ultrasonic waves. It was assumed that the ultrasonic waves induce change in the structure of organic compounds and contribute to the acceleration of biodegradability, including refractive substances in the leachate, so that will increase the effectiveness of their treatment in biological processes. We observed a marked increase in BOD leachate when subjected to the action of utradźwięowego. Ratio BOD / COD was 27% higher compared to the value of this ratio for leachate nienadźwiękawianych. It was found that the process of sonification leachate clearly influenced the formation and release of aliphatic compounds. These changes suggest a possible violation of the chemical structure of organic compounds in the leachate thereby give compounds of the chemical structure more susceptible to biodegradation.

Keywords: IR spectra, landfill leachate, organic pollutants, ultrasound

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Authors: Payman Davoodi-Nasab, Ahmad Rahbar-Kelishami, Jaber Safdari, Hossein Abolghasemi

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The high purity rare earth elements (REEs) have been vastly used in the field of chemical engineering, metallurgy, nuclear energy, optical, magnetic, luminescence and laser materials, superconductors, ceramics, alloys, catalysts, and etc. Neodymium is one of the most abundant rare earths. By development of a neodymium–iron–boron (Nd–Fe–B) permanent magnet, the importance of neodymium has dramatically increased. Solvent extraction processes have many operational limitations such as large inventory of extractants, loss of solvent due to the organic solubility in aqueous solutions, volatilization of diluents, etc. One of the promising methods of liquid membrane processes is emulsion liquid membrane (ELM) which offers an alternative method to the solvent extraction processes. In this work, a study on Nd extraction through multi-walled carbon nanotubes (MWCNTs) assisted ELM using response surface methodology (RSM) has been performed. The ELM composed of diisooctylphosphinic acid (CYANEX 272) as carrier, MWCNTs as nanoparticles, Span-85 (sorbitan triooleate) as surfactant, kerosene as organic diluent and nitric acid as internal phase. The effects of important operating variables namely, surfactant concentration, MWCNTs concentration, and treatment ratio were investigated. Results were optimized using a central composite design (CCD) and a regression model for extraction percentage was developed. The 3D response surfaces of Nd(III) extraction efficiency were achieved and significance of three important variables and their interactions on the Nd extraction efficiency were found out. Results indicated that introducing the MWCNTs to the ELM process led to increasing the Nd extraction due to higher stability of membrane and mass transfer enhancement. MWCNTs concentration of 407 ppm, Span-85 concentration of 2.1 (%v/v) and treatment ratio of 10 were achieved as the optimum conditions. At the optimum condition, the extraction of Nd(III) reached the maximum of 99.03%.

Keywords: emulsion liquid membrane, extraction of neodymium, multi-walled carbon nanotubes, response surface method

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Authors: Reyna Singh, David Lokhat, Milan Carsky

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The world crude oil demand is projected to rise to 108.5 million bbl/d by the year 2035. With reserves estimated at 869 billion tonnes worldwide, coal is an abundant resource. This work was aimed at producing a high value hydrocarbon liquid product from the Direct Coal Liquefaction (DCL) process at, comparatively, mild operating conditions. Via hydrogenation, the temperature-staged approach was investigated. In a two reactor lab-scale pilot plant facility, the objectives included maximising thermal dissolution of the coal in the presence of a hydrogen donor solvent in the first stage, subsequently promoting hydrogen saturation and hydrodesulphurization (HDS) performance in the second. The feed slurry consisted of high grade, pulverized bituminous coal on a moisture-free basis with a size fraction of < 100μm; and Tetralin mixed in 2:1 and 3:1 solvent/coal ratios. Magnetite (Fe3O4) at 0.25wt% of the dry coal feed was added for the catalysed runs. For both stages, hydrogen gas was used to maintain a system pressure of 100barg. In the first stage, temperatures of 250℃ and 300℃, reaction times of 30 and 60 minutes were investigated in an agitated batch reactor. The first stage liquid product was pumped into the second stage vertical reactor, which was designed to counter-currently contact the hydrogen rich gas stream and incoming liquid flow in the fixed catalyst bed. Two commercial hydrotreating catalysts; Cobalt-Molybdenum (CoMo) and Nickel-Molybdenum (NiMo); were compared in terms of their conversion, selectivity and HDS performance at temperatures 50℃ higher than the respective first stage tests. The catalysts were activated at 300°C with a hydrogen flowrate of approximately 10 ml/min prior to the testing. A gas-liquid separator at the outlet of the reactor ensured that the gas was exhausted to the online VARIOplus gas analyser. The liquid was collected and sampled for analysis using Gas Chromatography-Mass Spectrometry (GC-MS). Internal standard quantification methods for the sulphur content, the BTX (benzene, toluene, and xylene) and alkene quality; alkanes and polycyclic aromatic hydrocarbon (PAH) compounds in the liquid products were guided by ASTM standards of practice for hydrocarbon analysis. In the first stage, using a 2:1 solvent/coal ratio, an increased coal to liquid conversion was favoured by a lower operating temperature of 250℃, 60 minutes and a system catalysed by magnetite. Tetralin functioned effectively as the hydrogen donor solvent. A 3:1 ratio favoured increased concentrations of the long chain alkanes undecane and dodecane, unsaturated alkenes octene and nonene and PAH compounds such as indene. The second stage product distribution showed an increase in the BTX quality of the liquid product, branched chain alkanes and a reduction in the sulphur concentration. As an HDS performer and selectivity to the production of long and branched chain alkanes, NiMo performed better than CoMo. CoMo is selective to a higher concentration of cyclohexane. For 16 days on stream each, NiMo had a higher activity than CoMo. The potential to cover the demand for low–sulphur, crude diesel and solvents from the production of high value hydrocarbon liquid in the said process, is thus demonstrated.

Keywords: catalyst, coal, liquefaction, temperature-staged

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Authors: Anatoly A. Kuznetsov, Pavel G. Berezhko, Sergey M. Kunavin, Eugeny V. Zhilkin, Maxim V. Tsarev, Vyacheslav V. Yaroshenko, Valery V. Mokrushin, Olga Y. Yunchina, Sergey A. Mityashin

Abstract:

The acoustic emission is caused by short-time propagation of elastic waves that are generated as a result of quick energy release from sources localized inside some material. In particular, the acoustic emission phenomenon lies in the generation of acoustic waves resulted from the reconstruction of material internal structures. This phenomenon is observed at various physicochemical transformations, in particular, at those accompanying hydrogenation processes of metals or intermetallic compounds that make it possible to study parameters of these transformations through recording and analyzing the acoustic signals. It has been known that at the interaction between metals or inter metallides with hydrogen the most intensive acoustic signals are generated as a result of cracking or crumbling of an initial compact powder sample as a result of the change of material crystal structure under hydrogenation. This work is dedicated to the study into changes occurring in metallic titanium samples at their interaction with hydrogen and followed by acoustic emission signals. In this work the subjects for investigation were specimens of metallic titanium in two various initial forms: titanium sponge and fine titanium powder made of this sponge. The kinetic of the interaction of these materials with hydrogen, the acoustic emission signals accompanying hydrogenation processes and the structure of the materials before and after hydrogenation were investigated. It was determined that in both cases interaction of metallic titanium and hydrogen is followed by acoustic emission signals of high amplitude generated on reaching some certain value of the atomic ratio [H]/[Ti] in a solid phase because of metal cracking at a macrolevel. The typical sizes of the cracks are comparable with particle sizes of hydrogenated specimens. The reasons for cracking are internal stresses initiated in a sample due to the increasing volume of a solid phase as a result of changes in a material crystal lattice under hydrogenation. When the titanium powder is used, the atomic ratio [H]/[Ti] in a solid phase corresponding to the maximum amplitude of an acoustic emission signal are, as a rule, higher than when titanium sponge is used.

Keywords: acoustic emission signal, cracking, hydrogenation, titanium specimen

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Authors: Nikolaos Mamalis

Abstract:

The work of the eminent architect and composer has undoubtedly been influenced both by his architecture and collaboration with Le Corbusier and by the conquests of the musical avant-garde of the 20th century (Schoenberg, Messian, Bartock, electroacoustic music). It is known that the golden mean and the Fibonacci sequence played a momentous role in the Architectural Avant-garde (Modulor) and expanded on musical pursuits. Especially in the 50s (serialism), it was a structural tool for composition. Xenakis' architectural and musical work (Sacrifice, Metastasis, Rebonds, etc.) received the influence of the Golden Section, as has been repeatedly demonstrated. However, the idea of this retrospective sequence and the reflection raised by the search for new proportions, both in the architectural and the musical work of Xenakis, was not limited to constituting a step, a workable formula that acted unifyingly with regard to the other parameters of the musical work, or as an aesthetic model that makes sense - philosophically and poetically - an anthropocentric dimension as in other composers (see Luigi Nono) ̇ triggered a qualitative leap, an opening of the composer to the assimilation of mathematical concepts and scientific types in music and the consolidation of new sound horizons of stochastic music.

Keywords: golden ratio, music, space, stochastic music

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Authors: Yeo Kyeong Lee, Ji Yeon Kang, Eun Mi Ryu, Hee Sun Kim, Yeong Soo Shin

Abstract:

The objective of this paper is an investigation of the effects of the thickness and axial loading during a fire test on the load-bearing capacity of a fire-damaged normal-strength concrete wall. Two factors are attributed to the temperature distributions in the concrete members and are mainly obtained through numerous experiments. Toward this goal, three wall specimens of different thicknesses are heated for 2 h according to the ISO-standard heating curve, and the temperature distributions through the thicknesses are measured using thermocouples. In addition, two wall specimens are heated for 2 h while simultaneously being subjected to a constant axial loading at their top sections. The test results show that the temperature distribution during the fire test depends on wall thickness and axial load during the fire test. After the fire tests, the specimens are cured for one month, followed by the loading testing. The heated specimens are compared with three unheated specimens to investigate the residual load-bearing capacities. The fire-damaged walls show a minor difference of the load-bearing capacity regarding the axial loading, whereas a significant difference became evident regarding the wall thickness. To validate the experiment results, finite element models are generated for which the material properties that are obtained for the experiment are subject to elevated temperatures, and the analytical results show sound agreements with the experiment results. The analytical method based on validated thought experimental results is applied to generate the fire-damaged walls with 2,800 mm high considering the buckling effect: typical story height of residual buildings in Korea. The models for structural analyses generated to deformation shape after thermal analysis. The load-bearing capacity of the fire-damaged walls with pin supports at both ends does not significantly depend on the wall thickness, the reason for it is restraint of pinned ends. The difference of the load-bearing capacity of fire-damaged walls as axial load during the fire is within approximately 5 %.

Keywords: normal-strength concrete wall, wall thickness, axial-load ratio, slenderness ratio, fire test, residual strength, finite element analysis

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Authors: Sofiqul Islam, V. Murugan, Prema Kumari, Hari

Abstract:

Gentamicin is a broad spectrum water-soluble aminoglycoside antibiotics produced by the fermentation process of microorganism known as Micromonospora purpurea. It is widely used for the treatment of infection caused by both gram positive and gram negative bacteria. Gentamicin consists of a mixture of aminoglycoside components like C1, C1a, C2a, and C2. The molecular structure of Gentamicin and its related substances showed that it has lack of presence of chromophore group in the molecule due to which the detection of such components were quite critical and challenging. In this study, a simple Reversed Phase-High Performance Liquid Chromatographic (RP-HPLC) method using ultraviolet (UV) detector was developed and validated for quantification of the related substances present in Gentamicin drug substances. The method was achieved by using Thermo Scientific Hypersil Gold analytical column (150 x 4.6 mm, 5 µm particle size) with isocratic elution composed of methanol: water: glacial acetic acid: sodium hexane sulfonate in the ratio 70:25:5:3 % v/v/v/w as a mobile phase at a flow rate of 0.5 mL/min, column temperature was maintained at 30 °C and detection wavelength of 330 nm. The four components of Gentamicin namely Gentamicin C1, C1a, C2a, and C2 were well separated along with the related substance present in Gentamicin. The Limit of Quantification (LOQ) values were found to be at 0.0075 mg/mL. The accuracy of the method was quite satisfactory in which the % recovery was resulted between 95-105% for the related substances. The correlation coefficient (≥ 0.995) shows the linearity response against concentration over the range of Limit of Quantification (LOQ). Precision studies showed the % Relative Standard Deviation (RSD) values less than 5% for its related substance. The method was validated in accordance with the International Conference of Harmonization (ICH) guideline with various parameters like system suitability, specificity, precision, linearity, accuracy, limit of quantification, and robustness. This proposed method was easy and suitable for use for the quantification of related substances in routine analysis of Gentamicin formulations.

Keywords: reversed phase-high performance liquid chromatographic (RP-HPLC), high performance liquid chromatography, gentamicin, isocratic, ultraviolet

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Authors: E. Y. Jo, S. M. Park, I. S. Yeo, K. K. Kim, S. J. Park, Y. K. Kim, Y. D. Kim, C. G. Park

Abstract:

SO3 is created in small quantities during the combustion of fuel that contains sulfur, with the quantity produced a function of the boiler design, fuel sulfur content, excess air level, and the presence of oxidizing agents. Typically, about 1% of the fuel sulfur will be oxidized to SO3, but it can range from 0.5% to 1.5% depending on various factors. Combustion of fuels that contain oxidizing agents, such as certain types of fuel oil or petroleum coke, can result in even higher levels of oxidation. SO3 levels in the flue gas emitted by combustion are very high, which becomes a cause of machinery corrosion or a visible blue plume. Because of that, power plants firing petroleum residues need to installation of SO3 removal system. In this study, SO3 removal system using salt solution was developed and several salts solutions were tested for obtain optimal solution for SO3 removal system. Response surface methodology was used to optimize the operation parameters such as gas-liquid ratio, concentration of salts.

Keywords: flue gas desulfurization, petroleum cokes, Sulfur trioxide, SO3 removal

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Authors: Semachew M. Kassa, Africa M Geremew, Tezera F. Azmatch, Nandyala Darga Kumar

Abstract:

Frequency ratio (FR) and analytical hierarchy process (AHP) methods are developed based on past landslide failure points to identify the landslide susceptibility mapping because landslides can seriously harm both the environment and society. However, it is still difficult to select the most efficient method and correctly identify the main driving factors for particular regions. In this study, we used fourteen landslide conditioning factors (LCFs) and five soft computing algorithms, including Random Forest (RF), Support Vector Machine (SVM), Logistic Regression (LR), Artificial Neural Network (ANN), and Naïve Bayes (NB), to predict the landslide susceptibility at 12.5 m spatial scale. The performance of the RF (F1-score: 0.88, AUC: 0.94), ANN (F1-score: 0.85, AUC: 0.92), and SVM (F1-score: 0.82, AUC: 0.86) methods was significantly better than the LR (F1-score: 0.75, AUC: 0.76) and NB (F1-score: 0.73, AUC: 0.75) method, according to the classification results based on inventory landslide points. The findings also showed that around 35% of the study region was made up of places with high and very high landslide risk (susceptibility greater than 0.5). The very high-risk locations were primarily found in the western and southeastern regions, and all five models showed good agreement and similar geographic distribution patterns in landslide susceptibility. The towns with the highest landslide risk include Amhara Saint Town's western part, the Northern part, and St. Gebreal Church villages, with mean susceptibility values greater than 0.5. However, rainfall, distance to road, and slope were typically among the top leading factors for most villages. The primary contributing factors to landslide vulnerability were slightly varied for the five models. Decision-makers and policy planners can use the information from our study to make informed decisions and establish policies. It also suggests that various places should take different safeguards to reduce or prevent serious damage from landslide events.

Keywords: artificial neural network, logistic regression, landslide susceptibility, naïve Bayes, random forest, support vector machine

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Authors: Mounira Laabidi, Rafik Zayani, Ridha Bouallegue, Daniel Roviras

Abstract:

The Filter Bank multicarrier with Offset Quadrature Amplitude Modulation (FBMC-OQAM) has been introduced to overcome the poor spectral characteristics and the waste in both bandwidth and energy caused by the use of the cyclic prefix. However, the FBMC-OQAM signals suffer from the high Peak to Average Power Ratio (PAPR) problem. Due to the overlapping structure of the FBMC-OQAM signals, directly applying the PAPR reduction schemes conceived for the OFDM one turns out to be ineffective. In this paper, we address the problem of PAPR reduction for FBMC-OQAM systems by suggesting a new scheme based on an improved version of Active Constellation Extension scheme (ACE) of OFDM. The proposed scheme, named Rolling Window ACE, takes into consideration the overlapping naturally emanating from the FBMC-OQAM signals.

Keywords: ACE, FBMC, OQAM, OFDM, PAPR, rolling-window

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Authors: H. M. Nanjundaswamy, S. K. Nath, S. Ray

Abstract:

TiO₂ particles have been added in molten aluminium to result in aluminium based cast Al/Al₃Ti-Al₂O₃ composite, which has been added then to molten magnesium to synthesize magnesium based cast Mg-Al/Al₃Ti-Al₂O₃ composite. The nominal compositions in terms of Mg, Al, and TiO₂ contents in the magnesium based composites are Mg-9Al-0.6TiO₂, Mg-9Al-0.8TiO₂, Mg-9Al-1.0TiO₂ and Mg-9Al-1.2TiO₂ designated respectively as MA6T, MA8T, MA10T and MA12T. The microstructure of the cast magnesium based composite shows grayish rods of intermetallics Al₃Ti, inherited from aluminium based composite but these rods, on hot forging, breaks into smaller lengths decreasing the average aspect ratio (length to diameter) from 7.5 to 3.0. There are also cavities in between the broken segments of rods. β-phase in cast microstructure, Mg₁₇Al₁₂, dissolves during heating prior to forging and re-precipitates as relatively finer particles on cooling. The amount of β-phase also decreases on forging as segregation is removed. In both the cast and forged composite, the Brinell hardness increases rapidly with increasing addition of TiO₂ but the hardness is higher in forged composites by about 80 BHN. With addition of higher level of TiO₂ in magnesium based cast composite, yield strength decreases progressively but there is marginal increase in yield strength over that of the cast Mg-9 wt. pct. Al, designated as MA alloy. But the ultimate tensile strength (UTS) in the cast composites decreases with the increasing particle content indicating possibly an early initiation of crack in the brittle inter-dendritic region and their easy propagation through the interfaces of the particles. In forged composites, there is a significant improvement in both yield strength and UTS with increasing TiO₂ addition and also, over those observed in their cast counterpart, but at higher addition it decreases. It may also be noted that as in forged MA alloy, incomplete recovery of forging strain increases the strength of the matrix in the composites and the ductility decreases both in the forged alloy and the composites. Initiation fracture toughness, J_IC, decreases drastically in cast composites compared to that in MA alloy due to the presence of intermetallic Al₃Ti and Al₂O₃ particles in the composite. There is drastic reduction of J_IC on forging both in the alloy and the composites, possibly due to incomplete recovery of forging strain in both as well as breaking of Al₃Ti rods and the voids between the broken segments of Al₃Ti rods in composites. The ratio of tearing modulus to elastic modulus in cast composites show higher ratio, which increases with the increasing TiO₂ addition. The ratio decreases comparatively more on forging of cast MA alloy than those in forged composites.

Keywords: composite, fracture toughness, forging, tensile properties

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Authors: Ali Ghorbanipour

Abstract:

The aim of this study is to investigate the drug resistance pattern and the value of the MIC (minimum inhibitory concentration)method to reduce the impact of infectious diseases and the slow development of resistance. Method: The study was conducted on clinical specimens collected between 2018 to 2021. identification of isolates and antibiotic susceptibility testing were performed using conventional biochemical tests. Antibiotic resistance was determined using kibry-Bauer disk diffusion and MIC by E-test methods comparative with microdilution plate elisa method. Results were interpreted according to CLSI. Results: Out of 249600 different clinical specimens, 18720 different pathogenic bacteria by overall detection ratio 7.7% were detected. Among pathogen bacterial were Gram negative bacteria (70%,n=13000) and Gram positive bacteria(30%,n=5720).Medically relevant gram-negative bacteria include a multitude of species such as E.coli , Klebsiella .spp , Pseudomonas .aeroginosa , Acinetobacter .spp , Enterobacterspp ,and gram positive bacteria Staphylococcus.spp , Enterococcus .spp , Streptococcus .spp was isolated . Conclusion: Our results highlighted that the resistance ratio among Gram Negative bacteria and Gram positive bacteria with different infection is high it suggest constant screening and follow-up programs for the detection of antibiotic resistance and the value of MIC drug susceptibility reporting that provide a new way to the usage of resistant antibiotic in combination with other antibiotics or accurate weight of antibiotics that inhibit or kill bacteria. Evaluation of wrong medication in the expansion of resistance and side effects of over usage antibiotics are goals. Ali ghorbanipour presently working as a supervision at the microbiology department of Massoud medical laboratory. Iran. Earlier, he worked as head department of pulmonary infection in firoozgarhospital, Iran. He received master degree in 2012 from Fergusson College. His research prime objective is a biologic wound dressing .to his credit, he has Published10 articles in various international congresses by presenting posters.

Keywords: antimicrobial profile, MIC & MBC Method, microplate antimicrobial assay, E-test

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Authors: Kun-Ting Song, Christian Schott, Peter Schneider, Sebastian Watzele, Regina Kluge, Elena Gubanova, Aliaksandr S. Bandarenka

Abstract:

The combination of electrochemical impedance spectroscopy (EIS) and the hydrodynamic technique like rotation disc electrode (RDE) provides a critical method for quantitively investigating mechanisms of hydrogen evolution reaction (HER) in acidic and alkaline media. Pt5Gd represented higher HER activities than polycrystalline Pt (Pt(pc)) by means of the surface strain effects. The model of the equivalent electric circuit to fit the impedance data under the RDE configurations is developed. To investigate the relative reaction contribution, the ratio of the charge transfer reactions of the Volmer-Heyrovsky and Volmer-Tafel pathways on Pt and Pt5Gd electrodes is determined. The ratio remains comparably similar in acidic media, but it changes in alkaline media with Volmer–Heyrovsky pathway dominating. This combined approach of EIS and RDE can help to study the electrolyte effects and other essential reactions for electrocatalysis in future work.

Keywords: hydrogen evolution reaction, electrochemical impedance spectroscopy, hydrodynamic methods, electrocatalysis, electrochemical interface

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