Search results for: Sigmoid decreasing Inertia Weight

Authors: R. Ziaie Moayed, M. Hamidzadeh

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The use of waste rubber chips not only can be of great importance in terms of the environment, but also can be used to increase the shear strength of soils. The purpose of this study was to evaluate the variation of the internal friction angle of liquefiable sandy soil using waste rubber chips. For this purpose, the geotechnical properties of unmodified and modified soil samples by waste lining rubber chips have been evaluated and analyzed by performing the triaxial consolidated drained test. In order to prepare the laboratory specimens, the sandy soil in part of Rudsar shores in Gilan province, north of Iran with high liquefaction potential has been replaced by two percent of waste rubber chips. Samples have been compressed until reaching the two levels of density of 15.5 and 16.7 kN/m³. Also, in order to find the optimal length of chips in sandy soil, the rectangular rubber chips with the widths of 0.5 and 1 cm and the lengths of 0.5, 1, and 2 cm were used. The results showed that the addition of rubber chips to liquefiable sandy soil greatly increases the shear resistance of these soils. Also, it can be seen that decreasing the width and increasing the length-to-width ratio of rubber chips has a direct impact on the shear strength of the modified soil samples with rubber chips.

Keywords: Improvement, shear strength, internal friction angle, sandy soil, rubber chip.

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Authors: S. Karabulut, A. Güllü, A. Güldas, R. Gürbüz

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This study investigates the effects of the lead angle and chip thickness variation on surface roughness during the machining of compacted graphite iron using ceramic cutting tools under dry cutting conditions. Analytical models were developed for predicting the surface roughness values of the specimens after the face milling process. Experimental data was collected and imported to the artificial neural network model. A multilayer perceptron model was used with the back propagation algorithm employing the input parameters of lead angle, cutting speed and feed rate in connection with chip thickness. Furthermore, analysis of variance was employed to determine the effects of the cutting parameters on surface roughness. Artificial neural network and regression analysis were used to predict surface roughness. The values thus predicted were compared with the collected experimental data, and the corresponding percentage error was computed. Analysis results revealed that the lead angle is the dominant factor affecting surface roughness. Experimental results indicated an improvement in the surface roughness value with decreasing lead angle value from 88° to 45°.

Keywords: CGI, milling, surface roughness, ANN, regression, modeling, analysis.

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Authors: Faroudja Meziani, Amar Kahil

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In order to study the variation in settlement of soil under a dyke dam, the modelisation in our study consists of applying an imposed displacement at the base of the mass of soil (consisting of a saturated sand). The imposed displacement follows the evolution of acceleration of the earthquake of Boumerdes 2003 in Algeria. Moreover, the gravity load is taken into consideration by taking account the specific weight of the materials constituting the dyke. The results obtained show that the gravity loads have a direct influence on the evolution of settlement, especially at the center of the dyke where these loads are higher.

Keywords: Settlement, dynamic analysis, rockfill dam, effect of earthquake, soil dynamics.

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Authors: Aree Thongpukdee, Ekasit Nisayan, Chockpisit Thepsithar

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Shoots, with three leaves, of Paphiopedilum 'Delrosi' were used as explants for multiple shoot induction. Modified Hyponex medium was supplemented with thidiazuron (TDZ), N6- benzyladenine (BA) or kinetin (Kn) alone and in combinations with 2,4-dichlorophenoxyacetic acid (2,4-D). All explants were cultured for 15 weeks. It was found that TDZ alone at the concentration of 0.45μM or in combination with 4.52μM 2,4-D and 8.88μM BA in combination with 13.56μM 2,4-D promoted multiple shoots. The highest shoot sprouting efficiencies (80.0, 90.0 and 80.0%) and new shoot numbers (1.5, 1.3 and 1.1) were obtained, respectively. Fresh weight, height, numbers of leaf and root of new shoots and initial explants were discussed.

Keywords: Paphiopedilum, terrestrial orchids, in vitro culture, micropropagation, multiple shoot induction

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Authors: K. A. Mistry, I. B. Patel, A. H. Prajapati

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In the present work, the alloy of Bismuth-lead is prepared on the basis of percentage of molecular weight 9:1, 5:5 and 1:9 ratios and grown by Zone- Refining Technique under a vacuum atmosphere. The EDAX of these samples are done and the results are reported. Micro hardness test has been used as an alternative test for measuring material’s tensile properties. The effect of temperature and load on the hardness of the grown alloy has been studied. Further the comparative studies of work hardening coefficients are reported.

Keywords: EDAX, hardening coefficient, Micro hardness, Bi-Pb alloy.

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Authors: Sutar Rani Ananda, M. V. Murugendrappa

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To investigate electrical properties of conducting polypyrrole (PPy) and cobalt aluminum oxide (CAO) nanocomposites, impedance analyzer in frequency range of 100 Hz to 5 MHz is used. In this work, PPy/CAO nanocomposites were synthesized by chemical oxidation polymerization method in different weight percent of CAO in PPy. The dielectric properties and AC conductivity studies were carried out for different nanocomposites in temperature range of room temperature to 180 °C. With the increase in frequency, the dielectric constant for all the nanocomposites was observed to decrease. AC conductivity of PPy was improved by addition of CAO nanopowder.

Keywords: Polypyrrole, dielectric constant, dielectric loss, AC conductivity.

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Authors: T. Khenenou, M. Melizi, H. Benzaoui

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The study of morphometric and histologic evolutions of the Bursa of Fabricus during 27 weeks of post-hashing age, realized on 88 subjects of broiler chicken they permitted to collect information about the morpho-histological aspect according to their post-hashing age; showed the size and the weight of the Bursa of Fabricius which reach their maximum between the 10th and the 11th week of age and the physiologic involution phenomena. These variations are in close relationship to the sexual maturity. These results can be used in the diagnosis of viral disease such as the Gumboro disease, Marek disease.

Keywords: Broiler chicken, bursa of Fabricius, Morphohistology, post-hashing evolution.

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Authors: K. M. Mohamed Muneer, Raghu V. Prakash, Krishnan Balasubramaniam

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This paper presents the results of thermo-mechanical characterization of Glass/Epoxy composite specimens using Infrared Thermography technique. The specimens used for the study were fabricated in-house with three different lay-up sequences and tested on a servo hydraulic machine under uni-axial loading. Infrared Camera was used for on-line monitoring surface temperature changes of composite specimens during tensile deformation. Experimental results showed that thermomechanical characteristics of each type of specimens were distinct. Temperature was found to be decreasing linearly with increasing tensile stress in the elastic region due to thermo-elastic effect. Yield point could be observed by monitoring the change in temperature profile during tensile testing and this value could be correlated with the results obtained from stress-strain response. The extent of prior plastic deformation in the post-yield region influenced the slopes of temperature response during tensile loading. Partial unloading and reloading of specimens post-yield results in change in slope in elastic and plastic regions of composite specimens.

Keywords: Glass/Epoxy composites, Thermomechanical behavior, Infrared Thermography, Thermoelastic slope, Thermoplastic slope.

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Authors: Shiva Osouli, Maryam Atapour, Mehrdad Ahmadi, Shima Shokri

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Citrus leaf miner (Phyllocnistis citrella Stainton) is native to Asia and one of the most serious pests of Iran’s citrus nursery stocks. In the present study, the possibility of insect mass rearing on four various citrus hosts and the effects of gamma irradiation on the pupal mortality and reproduction of this pest were studied. Trifoliate orange and grapefruit showed less infection, while the number of pupae in Valencia oranges and sweet lemons cages was so high. There was not any significant difference between weight of male and female pupae among different citrus hosts, but generally the weight of male pupae was less than females. Use of Valencia orange or sweet lemons seedlings in especial dark emergence and oviposition cages could be recommended for mass rearing of this pest. In this study, the effects of gamma radiation at doses 100 to 450 Gy on biological and reproductive parameters of the pest has been determined. The results show that mean percent of pupal mortality increased with increasing doses and reached to 28.67% at 450 Gy for male pupae and 38.367% for female pupae. Also, the mean values of this parameter were higher for irradiated female, which indicated the higher sensitivity of this sex. The gamma ray irradiation from 200 and 300 Gy caused decrease in male and female adult moth longevity, respectively. The eggs were laid by emerged females, and their hatchability was decreased by increasing gamma doses. The fecundity of females in both combinations of crosses (irradiated male × normal female and irradiated female × normal male) did not differ, but fertility of laid eggs by irradiated female × normal male affected seriously and the mean values of this parameter reached to zero at 300 Gy. The hatchability percentage of produced eggs by normal female × irradiated male at 300 Gy was 23.29% and reached to less than 2 % at 450 Gy as the highest tested dose. The results of this test show that females have more radio-sensitivity in comparison to males.

Keywords: Citrus leaf miner, Phyllocnistis citrella, citrus hosts, mass rearing, sterile insect technique.

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Authors: Hyung-Nam Kim, Won-Yong Chae, Dong-Sul Shin, Ho-Sung Kim, Hee-Je Kim

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A wireless power transfer system can attribute to the fields in robot, aviation and space in which lightening the weight of device and improving the movement play an important role. A wireless power transfer system was investigated to overcome the inconvenience of using power cable. Especially a wireless power transfer technology is important element for mobile robots. We proposed the wireless power transfer system of the half-bridge resonant converter with the frequency tracking and optimized power transfer control unit. And the possibility of the application and development system was verified through the experiment with LED loads.

Keywords: Wireless Power Transmission (WPT), resonancefrequency, protection circuit. LED.

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Authors: R. Guliyev

Abstract:

The enhanced need for food items is receiving more importance due to a gradual increase in the world population and, in this scenario, fertilizers play a very important role in agriculture. In this study, the production of the normal superphosphate was investigated with a continuous chamber method by adding potassium chloride to a mixture of Hibin apatite and Kingisepp phosphorite. In the experiments, the following parameters were selected: The concentration of sulfuric acid (54–66% (w/w)), the stoichiometric norm of sulfuric acid (100, 107, 110, 114% (w/w)), the ratio of apatite/phosphorite in the mixture of phosphate (95/5, 90/10, 85/15, 80/20, 75/25, 70/30, 65/35,60/40, 55/45, 50/50 (w/w)), potassium chloride/the mixture of phosphate (1/50, 2/50, 3/50,4/50, 5/50 (w/w)), and the reaction time (2–8 min). It was observed that by adding potassium chloride to a low-grade phosphorite and using it to substitute a fraction of high-grade apatite in the normal superphosphate production not only resulted in a high-quality product but also eliminated the waiting period for the maturation of superphosphate in the storage. The objective of this study was to produce a normal superphosphate fertilizer by using a continuous chamber method in order to accelerate the production process and to reduce the environmental pollution caused by fluoride gases by eliminating the maturation time in the storage.

Keywords: Continuous chamber method, environmental pollution, fluoride gases.

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Authors: Juyi Park, Sang-Bum Lee, Jin-Wook Kim, Ji-Yoon Kim, Jung-Min Kim, Hee-Hwan Park, Jae-Won Seo, Gye-Hyung Kang, Soo-Ho Kim

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This paper presents a portable robot that is to use for welding process in shipbuilding yard. It has six degree of freedom and 3kg payload capability. Its weight is 21.5kg so that human workers can carry it to the work place. Its body mainly made of magnesium alloy and aluminum alloy for few parts that require high strength. Since the distance between robot and controller should be 50m at most, the robot controller controls the robot through EtherCAT. RTX and KPA are used for real time EtherCAT control on Windows XP. The performance of the developed robot was satisfactory, in welding of U type cell in shipbuilding yard.

Keywords: Portable welding robot, Shipbuilding, EtherCAT

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Authors: Karel Frydrýšek, Pavel Koštial, Karla Barabaszová, Jana Kukutschová

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This paper deals with a new way for designing external fixators applied in traumatology and orthopaedics. These fixators can be applied in the treatment of open and unstable fractures or for lengthening human or animal bones etc. The new design is based on the development of Ilizarov and other techniques (i.e. shape and weight optimalization based on composite materials, application of smart materials, nanotechnology, low x-ray absorption, antibacterial protection, patient's comfort, reduction in the duration of the surgical treatment, and cost).

Keywords: biomechanics, design, external fixators, newmaterials, traumatology

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Authors: Raluca Ionela Maxim

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Designing a gender responsive Science, Technology, Engineering and Mathematics (STEM) mobile game based learning solution (mGBL) is a challenge in terms of content, gamification level and equal engagement of girls and boys. The goal of this case study was to research and create a high-fidelity prototype design of a mobile game that contains role-models as avatars that guide and expose girls and boys to STEM learning content. For this research purpose it was applied the methodology of design sprint with five-phase process that combines design thinking principles. The technique of this methodology comprises smart interviews with STEM experts, mind-map creation, sketching, prototyping and usability testing of the interactive prototype of the gender responsive STEM mGBL. The results have shown that the effect of the avatar/role model had a positive impact. Therefore, by exposing students (boys and girls) to STEM role models in an mGBL tool is helpful for the decreasing of the gender inequalities in STEM fields.

Keywords: Design thinking, design sprint, gender-responsive STEM education, mobile game based learning, role-models.

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Authors: Mulugeta Shegaze, Mekitie Wondafrash, Alemayehu A. Alemayehu, Shikur Mohammed, Zewdu Shewangezaw, Mukerem Abdo, Gebresilasea Gendisha

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Background: The 2004 World Health Assembly called for specific actions to halt the overweight and obesity epidemic that is currently penetrating urban populations in the developing world. Adolescents require particular attention due to their vulnerability to develop obesity and the fact that adolescent weight tracks strongly into adulthood. However, there is scarcity of information on the modifiable risk factors to be targeted for primary intervention among urban adolescents in Ethiopia. This study was aimed at determining the magnitude and risk factors of overweight and obesity among high school adolescents in Addis Ababa. Methods: An institution-based cross-sectional study was conducted in February and March 2014 on 456 randomly selected adolescents from 20 high schools in Addis Ababa city.  Demographic data and other risk factors of overweight and obesity were collected using self-administered structured questionnaire, whereas anthropometric measurements of weight and height were taken using calibrated equipment and standardized techniques. The WHO STEPS instrument for chronic disease risk was applied to assess dietary habit and physical activity. Overweight and obesity status was determined based on BMI-for-age percentiles of WHO 2007 reference population. Results: The prevalence rates of overweight, obesity, and overall overweight/ obesity among high school adolescents in Addis Ababa were 9.7% (95%CI = 6.9-12.4%), 4.2% (95%CI = 2.3-6.0%), and 13.9% (95%CI = 10.6-17.1%), respectively. Overweight/obesity prevalence was highest among female adolescents, in private schools, and in the higher wealth category. In multivariable regression model, being female [AOR(95%CI) = 5.4(2.5,12.1)], being from private school [AOR(95%CI) = 3.0(1.4,6.2)], having >3 regular meals [AOR(95%CI) = 4.0(1.3,13.0)], consumption of sweet foods [AOR(95%CI) = 5.0(2.4,10.3)] and spending >3 hours/day sitting [AOR(95%CI) = 3.5(1.7,7.2)] were found to increase overweight/ obesity risk, whereas high Total Physical Activity level [AOR(95%CI) = 0.21(0.08,0.57)] and better nutrition knowledge [AOR(95%CI) = 0.160.07,0.37)] were found protective. Conclusions: More than one in ten of the high school adolescents were affected by overweight/obesity with dietary habit and physical activity are important modifiable risk factors. Well-tailored nutrition education program targeting lifestyle change should be initiated with more emphasis to female adolescents and students in private schools.

Keywords: Adolescents, NCDs, overweight, obesity.

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Authors: Farhad Kolahan, M. Hossein Abolbashari, Samaeddin Mohitzadeh

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Several methods are available for weight and shape optimization of structures, among which Evolutionary Structural Optimization (ESO) is one of the most widely used methods. In ESO, however, the optimization criterion is completely case-dependent. Moreover, only the improving solutions are accepted during the search. In this paper a Simulated Annealing (SA) algorithm is used for structural optimization problem. This algorithm differs from other random search methods by accepting non-improving solutions. The implementation of SA algorithm is done through reducing the number of finite element analyses (function evaluations). Computational results show that SA can efficiently and effectively solve such optimization problems within short search time.

Keywords: Simulated annealing, Structural optimization, Compliance, C.V. product.

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Authors: Janis Šliseris, Karlis Rocens

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Optimization of rational geometrical and mechanical parameters of panel with curved plywood ribs is considered in this paper. The panel consists of cylindrical plywood ribs manufactured from Finish plywood, upper and bottom plywood flange, stiffness diaphragms. Panel is filled with foam. Minimal ratio of structure self weight and load that could be applied to structure is considered as rationality criteria. Optimization is done, by using classical beam theory without nonlinearities. Optimization of discreet design variables is done by Genetic algorithm.

Keywords: Curved plywood ribs, genetic algorithm, rationalparameters of ribbed panel, structure optimization.

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Authors: S. Yaglikci, B. Salgara, F. Soysal, B. Cicek

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Chemical vapor deposition method was used to produce carbon nanotubes on an iron based catalyst from acetylene. Gas-phase samples collected from the different positions of the tubular reactor were analyzed by GC/MS. A variety of species ranging from hydrogen to naphthalene were observed and changes in their concentrations were plotted against the reactor position. Briefly benzene, toluene, styrene, indene and naphthalene were the main higher molecular weight species and vinylacetylene and diacetylene were the important intermediates. Nanotube characterization was performed by scanning electron microscopy and transmission electron microscopy.

Keywords: Carbon nanotubes, chemical vapor deposition, GC/MS, species profile

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Authors: Eva Ungure, Sandra Muizniece-Brasava, Lija Dukalska, Vita Levkane

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The objective of the research was to evaluate the quality of milk pomade sweet – sherbet packed in different packaging materials (Multibarrier 60, met.BOPET/PE, Aluthen), by several packaging technologies – active and modified atmosphere (MAP) (consisting of 100% CO2), and control – in air ambiance. Experiments were carried out at the Faculty of Food Technology of Latvia University of Agriculture. Samples were stored at the room temperature +21±1 °C. The physiochemical properties – weight losses, moisture, hardening, colour and changes in headspace atmosphere concentration (CO2 and O2) of packs were analysed before packaging and after 2, 4, 6, 8, 10 and 12 storage weeks.

Keywords: packaging, shelf life, sherbet with crunchy peanut chip's

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Authors: P. Kamphikul, P. Krachodnok, R. Wongsan

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This paper presents the gain improvement of a sector antenna for mobile phone base station by using the new technique to enhance its gain for microstrip antenna (MSA) array without construction enlargement. The curved woodpile Electromagnetic Band Gap (EBG) has been utilized to improve the gain instead. The advantages of this proposed antenna are reducing the length of MSAs array but providing the higher gain and easy fabrication and installation. Moreover, it provides a fan-shaped radiation pattern, wide in the horizontal direction and relatively narrow in the vertical direction, which appropriate for mobile phone base station. The paper also presents the design procedures of a 1x8 MSAs array associated with U-shaped reflector for decreasing their back and side lobes. The fabricated curved woodpile EBG exhibits bandgap characteristics at 2.1 GHz and is utilized for realizing a resonant cavity of MSAs array. This idea has been verified by both the Computer Simulation Technology (CST) software and experimental results. As the results, the fabricated proposed antenna achieves a high gain of 20.3 dB and the half-power beam widths in the E- and H-plane of 36.8 and 8.7 degrees, respectively. Good qualitative agreement between measured and simulated results of the proposed antenna was obtained.

Keywords: Gain Improvement, Microstrip Antenna Array, Electromagnetic Band Gap, Base Station.

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Authors: F. Smach, M. Atri, J. Mitéran, M. Abid

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Face detection and recognition has many applications in a variety of fields such as security system, videoconferencing and identification. Face classification is currently implemented in software. A hardware implementation allows real-time processing, but has higher cost and time to-market. The objective of this work is to implement a classifier based on neural networks MLP (Multi-layer Perceptron) for face detection. The MLP is used to classify face and non-face patterns. The systm is described using C language on a P4 (2.4 Ghz) to extract weight values. Then a Hardware implementation is achieved using VHDL based Methodology. We target Xilinx FPGA as the implementation support.

Keywords: Classification, Face Detection, FPGA Hardware description, MLP.

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Authors: H. Assaedi, F. U. A. Shaikh, I. M. Low

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Geopolymer composites reinforced with flax fabrics and nanoclay are fabricated and studied for physical and mechanical properties using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM). Nanoclay platelets at a weight of 1.0%, 2.0%, and 3.0% were added to geopolymer pastes. Nanoclay at 2.0 wt.% was found to improve density and decrease porosity while improving flexural strength and post-peak toughness. A microstructural analysis indicated that nanoclay behaves as filler and as an activator supporting geopolymeric reaction while producing a higher content geopolymer gel improving the microstructure of binders. The process enhances adhesion between the geopolymer matrix and flax fibres.

Keywords: Flax fibres, geopolymer, mechanical properties, nanoclay.

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Authors: J. Lebre, F. Brójo

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Pollution emission levels of aircraft engines are a nowadays high concern. Any technological advance that could reduce emission levels is always welcome. In what concerns aircraft engines, a possible solution for this problem could be the use of regenerators and intercoolers. These components might reduce the specific fuel consumption, increase efficiency and specific thrust and consequently reduce the pollution levels of the engine. This is not a novel solution. These heat exchangers are already is use in stationary engines. For aircraft engines, the extra weight of the needed hardware could overcome the fuel saved. This work compares a conventional engine with configurations that use intercoolers and regenerators.

Keywords: Intercooler, pollution, regenerator, turbofan

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Authors: Seyed Abolhasan Naeini, Mohammad Hossein Zade, E. Izadi, M. Hossein Zade

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The different seismic behavior of liquid storage tanks rather than conventional structures makes their responses more complicated. Uplifting and excessive settlement due to liquid sloshing are the most frequent damages in cylindrical liquid tanks after shell bucking failure modes. As a matter of fact, uses of liquid storage tanks because of the simple construction on compact layer of soil as a foundation are very conventional, but in some cases need to retrofit are essential. The tank seismic behavior can be improved by modifying dynamic characteristic of tank with verifying seismic loads as well as retrofitting and improving base ground. This paper focuses on a typical steel tank on loose, medium and stiff sandy soil and describes an evaluation of displacement of the tank before and after retrofitting. The Abaqus program was selected for its ability to include shell and structural steel elements, soil-structure interaction, and geometrical nonlinearities and contact type elements. The result shows considerable decreasing in settlement and uplifting in the case of retrofitted tank. Also, by increasing shear strength parameter of soil, the performance of the liquid storage tank under the case of seismic load increased.

Keywords: Steel tank, soil-structure, sandy soil, seismic load.

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Authors: Anto Antony Samy, Atefeh Golbang, Edward Archer, Alistair McIlhagger

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Fused Deposition Modelling (FDM) is one of the additive manufacturing techniques that has become highly attractive in the industrial and academic sectors. However, parts fabricated through FDM are highly susceptible to geometrical defects such as warpage, shrinkage, and delamination that can severely affect their function. Among the thermoplastic polymer feedstock for FDM, semi-crystalline polymers are highly prone to part distortion due to polymer crystallization. In this study, the influence of FDM processing conditions such as chamber temperature and print bed temperature on the induced thermal residual stress and resulting warpage are investigated using 3D transient thermal model for a semi-crystalline polymer. The thermo-mechanical properties and the viscoelasticity of the polymer, as well as the crystallization physics which considers the crystallinity of the polymer, are coupled with the evolving temperature gradient of the print model. From the results it was observed that increasing the chamber temperature from 25 °C to 75 °C leads to a decrease of 3.3% residual stress and increase of 0.4% warpage, while decreasing bed temperature from 100 °C to 60 °C resulted in 27% increase in residual stress and a significant rise of 137% in warpage. The simulated warpage data are validated by comparing it with the measured warpage values of the samples using 3D scanning.

Keywords: Finite Element Analysis, FEA, Fused Deposition Modelling, residual stress, warpage.

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Authors: Zhi Zhang, Tao Tang, Guangda Lu, Cheng Qin, Huogen Huang, Shaotao Zheng

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High purity hydrogen and the valuable by-product of carbon nanotubes (CNTs) can be produced by the methane catalytic decomposition. The methane conversion and the performance of CNTs were determined by the choices of catalysts and the condition of decomposition reaction. In this paper, Ni/MgO and Ni/O-D (oxidized diamond) catalysts were prepared by wetness impregnation method. The effects of reaction temperature and space velocity of methane on the methane conversion were investigated in a fixed-bed. The surface area, structure and micrography were characterized with BET, XPS, SEM, EDS technology. The results showed that the conversion of methane was above 8% within 150 min (T=500) for 33Ni/O-D catalyst and higher than 25% within 120 min (T=650) for 41Ni/MgO catalyst. The initial conversion increased with the increasing temperature of the decomposition reaction, but their catalytic activities decreased rapidly while at too higher temperature. To decrease the space velocity of methane was propitious to promote the methane conversion, but not favor of the hydrogen yields. The appearance of carbon resulted from the methane decomposition lied on the support type and the condition of catalytic reaction. It presented as fiber shape on the surface of Ni/O-D at the relatively lower temperature such as 500 and 550, but as grain shape stacked on and overlayed on the surface of the metal nickel while at 650. The carbon fiber can form on the Ni/MgO surface at 650 and the diameter of the carbon fiber increased with the decreasing space velocity.

Keywords: methane, catalytic decomposition, hydrogen, carbon nanofiber

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Authors: Ahmed Fathi Mohamed, Nasir Shafiq, M. F. Nuruddin, Ali Elheber

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Implementing significant advantages in the supply of self-compacting concrete (SCC) is necessary because of the, negative features of SCC. Examples of these features are the ductility problem along with the very high cost of its constituted materials. Silica fume with steel fiber can fix this matter by improving the ductility and decreasing the total cost of SCC by varying the cement ingredients. Many different researchers have found that there have not been enough research carried out on the steel fiber-reinforced self-compacting concrete (SFRSCC) produced with silica fume. This paper inspects both the fresh and the mechanical properties of SFRSCC with silica fume, the fresh qualities where slump flow, slump T₅₀ and V- funnel. While, the mechanical characteristics were the compressive strength, ultrasound pulse velocity (UPV) and elastic modulus of the concrete samples. The experimental results have proven that steel fiber can enhance the mechanical features. In addition, the silica fume within the entire hybrid mix may possibly adapt the fiber dispersion and strengthen deficits due to the fibers. It could also improve the strength plus the bond between the fiber and the matrix with a dense calcium silicate-hydrate gel in SFRSCC. The concluded result was predicted using linear mathematical models and was found to be in great agreement with the experimental results.

Keywords: Self-compacting concrete, silica fume, steel fiber, fresh and mechanical properties.

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Authors: Mustafa M. Donma, Orkide Donma

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A growing list of cancers might be influenced by obesity. Obesity is associated with an increased risk for the occurrence and development of some cancers. Inflammation can lead to cancer. It is one of the characteristic features of cancer and plays a critical role in cancer development. C-reactive protein (CRP) is under evaluation related to the new and simple prognostic factors in patients with metastatic renal cell cancer. Obesity can predict and promote systemic inflammation in healthy adults. BMI is correlated with hs-CRP. In this study, SII index and CRP values were evaluated in children with normal BMI and those within the range of different obesity grades to detect the tendency towards cancer in pediatric obesity. A total of one hundred and ninety-four children; thirty-five children with normal BMI, twenty overweight (OW), forty-seven obese (OB) and ninety-two morbid obese (MO) participated in the study. Age- and sex-matched groups were constituted using BMI-for age percentiles. Informed consent was obtained. Ethical Committee approval was taken. Weight, height, waist circumference (C), hip C, head C and neck C of the children were measured. The complete blood count test was performed. C-reactive protein analysis was performed. Statistical analyses were performed using SPSS. The degree for statistical significance was p≤0.05. SII index values were progressively increasing starting from normal weight (NW) to MO children. There is a statistically significant difference between NW and OB as well as MO children. No significant difference was observed between NW and OW children, however, a correlation was observed between NW and OW children. MO constitutes the only group, which exhibited a statistically significant correlation between SII index and CRP. Obesity-related bladder, kidney, cervical, liver, colorectal, endometrial cancers are still being investigated. Obesity, characterized as a chronic low-grade inflammation, is a crucial risk factor for colon cancer. Elevated childhood BMI values may be indicative of processes leading to cancer, initiated early in life. Prevention of childhood adiposity may decrease the cancer incidence in adults. To authors’ best knowledge, this study is the first to introduce SII index values during obesity of varying degrees of severity. It is suggested that this index seems to affect all stages of obesity with an increasing tendency and may point out the concomitant status of obesity and cancer starting from very early periods of life.

Keywords: Children, c- reactive protein, systemic immune-inflammation index, obesity.

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Authors: Shaiemaa, A. Momen, Dalia, A.M. Salem, Emad, M.S. Barakat, Mohamed, S. Salama

Abstract:

The present study has been conducted to characterize the prophenoloxidase (PPO) system of the desert locust, Schistocerca gregaria following injection of Bacillus thuringiensis kurstaki (Bt). The bulk of PPO system was associated with haemocytes and a little amount was found in plasma. This system was activated by different activators such as laminarin, lipopolysaccharide (LPS) and trypsin suggesting that the stimulatory mechanism may involve an enzyme cascade of one or more associated molecules. These activators did not activate all the molecules of the cascade. Presence of phenoloxidase activity (PO) coincides with the appearance of protein band with molecular weight (MW) 70.154 KD (Kilo Dalton).

Keywords: Schistocerca gregaria, haemolymph, proteins, prophenoloxidase system, phenoloxidase

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Authors: M. Zake, I. Barmina, A. Kolmickovs, R. Valdmanis

Abstract:

Experimental investigations of the DC electric field effect on thermal decomposition of biomass, formation of the axial flow of volatiles (CO, H2, CxHy), mixing of volatiles with swirling airflow at low swirl intensity (S ≈ 0.2-0.35), their ignition and on formation of combustion dynamics are carried out with the aim to understand the mechanism of electric field influence on biomass gasification, combustion of volatiles and heat energy production. The DC electric field effect on combustion dynamics was studied by varying the positive bias voltage of the central electrode from 0.6 kV to 3 kV, whereas the ion current was limited to 2 mA. The results of experimental investigations confirm the field-enhanced biomass gasification with enhanced release of volatiles and the development of endothermic processes at the primary stage of thermochemical conversion of biomass determining the field-enhanced heat energy consumption with the correlating decrease of the flame temperature and heat energy production at this stage of flame formation. Further, the field-enhanced radial expansion of the flame reaction zone correlates with a more complete combustion of volatiles increasing the combustion efficiency by 3% and decreasing the mass fraction of CO, H2 and CxHy in the products, whereas by 10% increases the average volume fraction of CO2 and the heat energy production downstream the combustor increases by 5-10% 

Keywords: Biomass, combustion, electrodynamic control, gasification.

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