Search results for: Hydrogen binding

Authors: S. Behnia, S. Fathizadeh

Abstract:

Conductivity properties of DNA molecule is investigated in a simple, but chemically specific approach that is intimately related to the Su-Schrieffer-Heeger (SSH) model. This model is a tight-binding linear nanoscale chain. We have tried to study the electrical current flowing in DNA and investigated the characteristic I-V diagram. As a result, It is shown that there are the (quasi-) ohmic areas in I-V diagram. On the other hand, the regions with a negative differential resistance (NDR) are detectable in diagram.

Keywords: Charge transfer in DNA, Chaos theory, Molecular electronics, Negative Differential resistance.

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Authors: B. Rezaei, G. R. Boroun, M. Abdolmaleki

Abstract:

The bound state energy of three quark systems is studied in the framework of a non- relativistic spin independent phenomenological model. The hyper- spherical coordinates are considered for the solution this system. According to Jacobi coordinate, we determined the bound state energy for (uud) and (ddu) quark systems, as quarks are flavorless mass, and it is restrict that choice potential at low and high range in nucleon bag for a bound state.

Keywords: Adiabatic expansion, grand angular momentum, binding energy, perturbation, baryons.

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Authors: Assel S. Issabekova, Olga A. Berillo, Vladimir A. Khailenko, Shara A. Atambayeva, Mireille Regnier, Anatoly T. Ivachshenko

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Regulatory relationships of 686 intronic miRNA and 784 intergenic miRNAs with mRNAs of 51 intronic miRNA coding genes were established. Interaction features of studied miRNAs with 5'UTR, CDS and 3'UTR of mRNA of each gene were revealed. Functional regions of mRNA were shown to be significantly heterogenous according to the number of binding sites of miRNA and to the location density of these sites.

Keywords: 5'UTR, 3'UTR, CDS, miRNA, target mRNA

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Authors: Maged A. Mossallam

Abstract:

The objective from this paper is to design a solar thermal engine for space vehicles orbital control and electricity generation. A computational model is developed for the prediction of the solar thermal engine performance for different design parameters and conditions in order to enhance the engine efficiency. The engine is divided into two main subsystems. First, the concentrator dish which receives solar energy from the sun and reflects them to the cavity receiver. The second one is the cavity receiver which receives the heat flux reflected from the concentrator and transfers heat to the fluid passing over. Other subsystems depend on the application required from the engine. For thrust application, a nozzle is introduced to the system for the fluid to expand and produce thrust. Hydrogen is preferred as a working fluid in the thruster application. Results model developed is used to determine the thrust for a concentrator dish 4 meters in diameter (provides 10 kW of energy), focusing solar energy to a 10 cm aperture diameter cavity receiver. The cavity receiver outer length is 50 cm and the internal cavity is 47 cm in length. The suggested design material of the internal cavity is tungsten to withstand high temperature. The thermal model and analysis shows that the hydrogen temperature at the plenum reaches 2000oK after about 250 seconds for hot start operation for a flow rate of 0.1 g/sec.Using solar thermal engine as an electricity generation device on earth is also discussed. In this case a compressor and turbine are used to convert the heat gained by the working fluid (air) into mechanical power. This mechanical power can be converted into electrical power by using a generator.

Keywords: Concentrated Solar Energy, Orbital Control, Power Generation, Solar Thermal Engine, Space Vehicles Propulsion

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Authors: A. A. Alhazza

Abstract:

The recycling process of Tungsten alloy (Swarf) by oxidation reduction technique have been investigated. The reduced powder was pressed under a pressure 20Kg/cm2 and sintered at 1150°C in dry hydrogen atmosphere. The particle size of the recycled alloy powder was 1-3 μm and the shape was regular at a reduction temperature 800°C. The chemical composition of the recycled alloy is the same as the primary Swarf.

Keywords: Recycling, Swarf, Oxidation, Reduction.

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Authors: Heri Hermansyah, Annisa Kurnia, A. Vania Anisya, Adi Surjosatyo, Yopi Sunarya, Rita Arbianti, Tania Surya Utami

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Lipase is one of biocatalyst which is applied commercially for the process in industries, such as bioenergy, food, and pharmaceutical industry. Nowadays, biocatalysts are preferred in industries because they work in mild condition, high specificity, and reduce energy consumption (high pressure and temperature). But, the usage of lipase for industry scale is limited by economic reason due to the high price of lipase and difficulty of the separation system. Immobilization of lipase is one of the solutions to maintain the activity of lipase and reduce separation system in the process. Therefore, we conduct a study about lipase immobilization with the adsorption-cross linking method using glutaraldehyde because this method produces high enzyme loading and stability. Lipase is immobilized on different kind of resin with the various functional group. Highest enzyme loading (76.69%) was achieved by lipase immobilized on anion macroporous which have anion functional group (OH^‑). However, highest activity (24,69 U/g support) through olive oil emulsion method was achieved by lipase immobilized on anion macroporous-chitosan which have amino (NH₂) and anion (OH^-) functional group. In addition, it also success to produce biodiesel until reach yield 50,6% through interesterification reaction and after 4 cycles stable 63.9% relative with initial yield. While for Aspergillus, niger lipase immobilized on anion macroporous-kitosan have unit activity 22,84 U/g resin and yield biodiesel higher than commercial lipase (69,1%) and after 4 cycles stable reach 70.6% relative from initial yield. This shows that optimum functional group on support for immobilization with adsorption-cross linking is the support that contains amino (NH₂) and anion (OH^-) functional group because they can react with glutaraldehyde and binding with enzyme prevent desorption of lipase from support through binding lipase with a functional group on support.

Keywords: Adsorption-Cross linking, lipase, resin, immobilization.

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Authors: Arun Kumar V.A., Keshav Mohan

Abstract:

Adenylate kinase (AK) catalyse the phosphotransferase reaction plays an important role in cellular energy homeostasis. The inhibitors of bacterial AK are useful in the treatment of several bacterial infections. To the novel inhibitors of AK, docking studies performed by using the 3D structure of Bacillus stearothermophilus adenylate kinase from protein data bank (IZIP). 46 Quinoxaline analogues were docked in 1ZIP and selected the highly interacting compounds based on their binding energies, for further studies

Keywords: Kinase, quinoxaline, homeostasis, inhibitor, nucleotide.

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Authors: H. M. Wilhelm, P. O. Fernandes, L. P. Dill, C. Steffens, K. G. Moscon, S. M. Peres, V. Bender, T. Marchesan, J. B. Ferreira Neto

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Deterioration of insulating oil is a natural process that occurs during transformers operation. However, this process can be accelerated by some factors, such as oxygen, high temperatures, metals and, moisture, which rapidly reduce oil insulating capacity and favor transformer faults. Parts of building materials of a transformer can be degraded and yield soluble compounds and insoluble particles that shorten the equipment life. Physicochemical tests, dissolved gas analysis (including propane, propylene and, butane), volatile and furanic compounds determination, besides quantitative and morphological analyses of particulate are proposed in this study in order to correlate transformers building materials degradation with insulating oil characteristics. The present investigation involves tests of medium temperature overheating simulation by means of an electric resistance wrapped with the following materials immersed in mineral insulating oil: test I) copper, tin, lead and, paper (heated at 350-400 °C for 8 h); test II) only copper (at 250 °C for 11 h); and test III) only paper (at 250 °C for 8 h and at 350 °C for 8 h). A different experiment is the simulation of electric arc involving copper, using an electric welding machine at two distinct energy sets (low and high). Analysis results showed that dielectric loss was higher in the sample of test I, higher neutralization index and higher values of hydrogen and hydrocarbons, including propane and butane, were also observed. Test III oil presented higher particle count, in addition, ferrographic analysis revealed contamination with fibers and carbonized paper. However, these particles had little influence on the oil physicochemical parameters (dielectric loss and neutralization index) and on the gas production, which was very low. Test II oil showed high levels of methane, ethane, and propylene, indicating the effect of metal on oil degradation. CO₂ and CO gases were formed in the highest concentration in test III, as expected. Regarding volatile compounds, in test I acetone, benzene and toluene were detected, which are oil oxidation products. Regarding test III, methanol was identified due to cellulose degradation, as expected. Electric arc simulation test showed the highest oil oxidation in presence of copper and at high temperature, since these samples had huge concentration of hydrogen, ethylene, and acetylene. Particle count was also very high, showing the highest release of copper in such conditions. When comparing high and low energy, the first presented more hydrogen, ethylene, and acetylene. This sample had more similar results to test I, pointing out that the generation of different particles can be the cause for faults such as electric arc. Ferrography showed more evident copper and exfoliation particles than in other samples. Therefore, in this study, by using different combined analytical techniques, it was possible to correlate insulating oil characteristics with possible contaminants, which can lead to transformers failure.

Keywords: Ferrography, gas analysis, insulating mineral oil, particle contamination, transformer failures.

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Authors: Abdoelmoniem A. Attaelmanan, Ahmed A. H. Siddig

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This study was conducted in light of continual global climate changes that projected increasing aridity, changes in soil fertility, and pollution. Plant growth and development largely depend on the combination of availing water and nutrients in the soil. Changes in the climate and atmospheric chemistry can cause serious effects on these growth factors. Plant carbon (C), nitrogen (N), and hydrogen (H) play a fundamental role in the maintenance of ecosystem structure and function. Hashab (Acacia senegal), which produces gum Arabic, supports dryland ecosystems in tropical zones by its potentiality to restore degraded soils; hence, it is ecologically and economically important for the dry areas of sub-Saharan Africa. The study aims at investigating the effects of water stress (simulated drought) and poor soil type on Acacia senegal C, N, and H contents. Seven-day-old seedlings were assigned to the treatments in split-plot design for four weeks. The main plot is irrigation interval (well-watered and water-stressed), and the subplot is soil types (silt and sandy soils). Seedling's C%, N%, and H% were measured using CHNS-O Analyzer and applying Standard Test Method. Irrigation intervals and soil types had no effects on seedlings and leaves C%, N%, and H%, irrigation interval had affected stem C% and H%, both irrigation intervals and soil types had affected root N% and interaction effect of water and soil was found on leaves and root's N%. Application of well-watered irrigation with soil that is rich in N and other nutrients would result in the greatest seedling C, N, and H content which will enhance growth and biomass accumulation and can play a crucial role in ecosystem productivity and services in the dryland regions.

Keywords: Acacia senegal, Africa, climate change, drylands, nutrients biomass, Sub-Sahara, Sudan.

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Authors: Jihane Abdessadak, Hicham Achelhi, Kamal Reklaoui

Abstract:

For any company or organization, change must be natural and binding in order to evolve its business, protect its durability and remain competitive. "Adapt or disappear". But how often managers, leaders or employees develop astonishing ideas that could improve several aspects of the organization and the feedback is less that encouraging and people give unrealistic judgments just to escape change. In this paper, we are going to discuss what we do know about change and resistance to change and what we can do to tame this phenomenon and, above all, the main steps that can follow an idea man in the delicate and decisive implementation of innovations.

Keywords: Innovation, change, resistance to change/innovation, barriers to innovation, levers of innovation.

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Authors: Anthony Ikechukwu Agboeze, Walter Timo de Vries, Pamela Durán-Díaz

Abstract:

Since attaining urban status, the population of Enugu, Nigeria, has continued to grow rapidly, leading to growing demands for housing by the teeming population which is predominantly low income. Several government dispensations have developed various affordable housing projects to help deliver decent housing to the Enugu populace. However, over a long period of usage, some of those housing projects in Enugu are unabatedly deteriorating into slums alongside rising housing deficits which has remained problematic for most Nigerian urban centers to address. Emerging from a literature review, this research posits that the link between slum and affordable housing is that both the seekers of affordable housing and slum housing are the low-income earners. This research further investigated the possible causalities of slum emergence from decently built affordable housing projects in Enugu, Nigeria. To do so, we first analyzed the Nigerian housing policy to examine how the policy addresses slum prevention. We further conducted semi-structured expert interviews (qualitative) to sample the views of private housing developers on the degeneration of government housing projects into slums in Enugu, Nigeria. Findings from the housing policy analysis suggest that the housing policy itself is not legally binding on anybody to implement. Sequel to this non-compulsory nature of the housing policy is the poor/non-implementation of the Nigerian housing policy, leading to a constant tendency by the government developers (contractors) to deliver potential slums. The expert respondents corroborated this viewpoint by suggesting that poor planning (including designs of the housing units and the master plan) and poor management (including non-maintenance, poor documentation, and inaccurate housing inventory) are germane to the emergence of slums from affordable housings. This research recommends periodic auditing of delivered housing projects to evaluate the developers’ adherence to the housing policy guidelines – it proposes incentives to policy adherents since the housing policy is not legally binding. We also recommend a participatory management to engage the occupants in the monitoring and reporting of breakdowns in the housing properties – to help improve the quality of management and maintenance to have slum-free settlements.

Keywords: Affordable housing, Enugu, low income, Nigeria, slum.

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Authors: Grujić S., Mihailović A., Kiurski J., Adamović S., Adamović D

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The aim of this study was to determine noise level of six different types of machines in printing companies in Novi Sad. The A-weighted levels on Leq, Lmax and Lmin Sound Pressure Level (SPL) in dBA were measured. It was found that the folders, offset printing presses and binding machines are the predominant noise sources. The noise levels produced by 12 of 38 machines exceed the limiting threshold level of 85 dBA, tolerated by law. Since it was determined that the average noise level for folders (87.7 dB) exceeds the permitted value the octave analysis of noise was performed.

Keywords: noise levels, octave analysis, printing machines.

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Authors: Malek Ali

Abstract:

Composites materials of Poly (vinyl alcohol) (PVA)/Chitosan (CS) have been synthesized and characterized successfully. HNTs have been added to composites to enhance the mechanical and degradation properties by hydrogen bonding interactions, compatibility, and chemical crosslink between HNTs and PVA. PVA/CS/HNTs composites prepared with different concentration ratio. SEM micrographs of composites surface showed that more agglomeration with more chitosan ratio. Mechanical and degradation properties were characterized and the result indicates that Mechanical and degradation of 80%PVA/5%Chitosan/15%HNTs higher than the others PVA/CS/HNTs composites.

Keywords: PVA/Chitosan, Composites, PVA/CS/HNTs, HNTs.

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Authors: Bogdan Il. Bogdanov, Dimitar R.Rusev, Yancho H. Hristov, Irena G. Markovska, Dimitar P.Georgiev

Abstract:

A newly designed gas-distributor for granulation of powdery materials in equilibrated fluidized bed and a system for collecting the granules prepared are suggested. The aim of these designs is to solve the problems arising by the granulation of powdery materials in fluidized bed devices. The gasdistributor and the collection system proved to be reliable at operation; they reduce the size of still zones, effectively disperse the binding solution in the bed and ensure the collection of granules of given diameter

Keywords: Distributor plate design, granulation, system design.

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Authors: Alan Luo, Hunter N. B. Moseley

Abstract:

Many macromolecular structure entries in the Protein Data Bank (PDB) have a range of regional (localized) quality issues, be it derived from X-ray crystallography, Nuclear Magnetic Resonance (NMR) spectroscopy, or other experimental approaches. However, most PDB entries are judged by global quality metrics like R-factor, R-free, and resolution for X-ray crystallography or backbone phi-psi distribution statistics and average restraint violations for NMR. Regional quality is often ignored when PDB entries are re-used for a variety of structurally based analyses. The binding of ligands, especially ligands involved in energy metabolism, is of particular interest in many structurally focused protein studies. Using a regional quality metric that provides chemically interpretable information from electron density maps, a significant number of outliers in regional structural quality was detected across X-ray crystallographic PDB entries for proteins bound to biochemically critical ligands. In this study, a series of analyses was performed to evaluate both specific and general potential factors that could promote these outliers. In particular, these potential factors were the minimum distance to a metal ion, the minimum distance to a crystal contact, and the isotropic atomic b-factor. To evaluate these potential factors, Fisher’s exact tests were performed, using regional quality criteria of outlier (top 1%, 2.5%, 5%, or 10%) versus non-outlier compared to a potential factor metric above versus below a certain outlier cutoff. The results revealed a consistent general effect from region-specific normalized b-factors but no specific effect from metal ion contact distances and only a very weak effect from crystal contact distance as compared to the b-factor results. These findings indicate that no single specific potential factor explains a majority of the outlier ligand-bound regions, implying that human error is likely as important as these other factors. Thus, all factors, including human error, should be considered when regions of low structural quality are detected. Also, the downstream re-use of protein structures for studying ligand-bound conformations should screen the regional quality of the binding sites. Doing so prevents misinterpretation due to the presence of structural uncertainty or flaws in regions of interest.

Keywords: Biomacromolecular structure, coenzyme, electron density discrepancy analysis, X-ray crystallography.

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Authors: Mustafa M. Donma, Orkide Donma

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Zinc (Zn) is a vital element required for growth and development particularly in children. It exhibits some protective effects against cardiovascular diseases (CVDs). Zn may be a potential biomarker of cardiovascular health. High sensitive cardiac troponin T (hs-cTnT) and cardiac myosin binding protein C (cMyBP-C) are new generation markers used for prediagnosis, diagnosis and prognosis of CVDs. The aim of this study is to determine Zn as well as new generation cardiac markers’ profiles in children with normal body mass index (N-BMI), obese (OB), morbid obese (MO) children and children with metabolic syndrome (MetS) findings. The association among them will also be investigated. Four study groups were constituted. The study protocol was approved by the institutional Ethics Committee of Tekirdag Namik Kemal University. Parents of the participants filled informed consent forms to participate in the study. Group 1 is composed of 44 children with N-BMI. Group 2 and Group 3 comprised 43 OB and 45 MO children, respectively. 45 MO children with MetS findings were included in Group 4. World Health Organization age- and sex-adjusted BMI percentile tables were used to constitute groups. These values were 15-85, 95-99 and above 99 for N-BMI, OB and MO, respectively. Criteria for MetS findings were determined. Routine biochemical analyses including Zn were performed. hs-cTnT and cMyBP-C concentrations were measured by enzyme-linked immunosorbent assay. Data were analyzed by using SPSS software. p < 0.05 was accepted as significant. Four groups were matched for age and gender. Decreased Zn concentrations were measured in Groups 2, 3 and 4 compared to Group 1. Groups did not differ from one another in terms of hs-cTnT. There were statistically significant differences between cMyBP-C levels of MetS group and N-BMI as well as OB groups. There was an increasing trend going from N-BMI group to MetS group. There were statistically significant negative correlations between Zn and hs-cTnT as well as cMyBP-C concentrations in MetS group. In conclusion, inverse correlations detected between Zn and new generation cardiac markers (hs-TnT and cMyBP-C) have pointed out that decreased levels of Zn accompany increased levels of hs-cTnT as well as cMyBP-C in children with MetS. This finding emphasizes that both Zn and these new generation cardiac markers may be evaluated as biomarkers of cardiovascular health during severe childhood obesity precipitated with MetS findings and also suggested as the messengers of the future risk in the adulthood periods of children with MetS.

Keywords: Cardiac myosin binding protein-C, cardiovascular diseases, children, high sensitive cardiac troponin T, obesity.

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Authors: Darby Tien-Hao Chang, Guan-Yu Shiu, You-Jie Sun

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Various cis-regulatory module (CRM) predictors have been proposed in the last decade. Several well-established CRM predictors adopted different categories of prediction strategies, including window clustering, probabilistic modeling and phylogenetic footprinting. Appropriate integration of them has a potential to achieve high quality CRM prediction. This study analyzed four existing CRM predictors (ClusterBuster, MSCAN, CisModule and MultiModule) to seek a predictor combination that delivers a higher accuracy than individual CRM predictors. 465 CRMs across 140 Drosophila melanogaster genes from the RED fly database were used to evaluate the integrated CRM predictor proposed in this study. The results show that four predictor combinations achieved superior performance than the best individual CRM predictor.

Keywords: Cis-regulatory module, transcription factor binding site.

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Authors: Ireneusz Majsterek, Anna Merecz, Agnieszka Sliwinska, Marcin Kosmalski, Jacek Kasznicki, Jozef Drzewoski

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Oxidative stress is considered to be the cause for onset and the progression of type 2 diabetes mellitus (T2DM) and complications including neuropathy. It is a deleterious process that can be an important mediator of damage to cell structures: protein, lipids and DNA. Data suggest that in patients with diabetes and diabetic neuropathy DNA repair is impaired, which prevents effective removal of lesions. Objective: The aim of our study was to evaluate the association of the hOGG1 (326 Ser/Cys) and XRCC1 (194 Arg/Trp, 399 Arg/Gln) gene polymorphisms whose protein is involved in the BER pathway with DNA repair efficiency in patients with diabetes type 2 and diabetic neuropathy compared to the healthy subjects. Genotypes were determined by PCR-RFLP analysis in 385 subjects, including 117 with type 2 diabetes, 56 with diabetic neuropathy and 212 with normal glucose metabolism. The polymorphisms studied include codon 326 of hOGG1 and 194, 399 of XRCC1 in the base excision repair (BER) genes. Comet assay was carried out using peripheral blood lymphocytes from the patients and controls. This test enabled the evaluation of DNA damage in cells exposed to hydrogen peroxide alone and in the combination with the endonuclease III (Nth). The results of the analysis of polymorphism were statistically examination by calculating the odds ratio (OR) and their 95% confidence intervals (95% CI) using the ¤ç2-tests. Our data indicate that patients with diabetes mellitus type 2 (including those with neuropathy) had higher frequencies of the XRCC1 399Arg/Gln polymorphism in homozygote (GG) (OR: 1.85 [95% CI: 1.07-3.22], P=0.3) and also increased frequency of 399Gln (G) allele (OR: 1.38 [95% CI: 1.03-1.83], P=0.3). No relation to other polymorphisms with increased risk of diabetes or diabetic neuropathy. In T2DM patients complicated by neuropathy, there was less efficient repair of oxidative DNA damage induced by hydrogen peroxide in both the presence and absence of the Nth enzyme. The results of our study suggest that the XRCC1 399 Arg/Gln polymorphism is a significant risk factor of T2DM in Polish population. Obtained data suggest a decreased efficiency of DNA repair in cells from patients with diabetes and neuropathy may be associated with oxidative stress. Additionally, patients with neuropathy are characterized by even greater sensitivity to oxidative damage than patients with diabetes, which suggests participation of free radicals in the pathogenesis of neuropathy.

Keywords: Diabetic neuropathy, oxidative stress, gene polymorphisms, oxidative DNA damage.

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Authors: A. M. Tahsini

Abstract:

Supersonic hydrogen-air cylindrical mixing layer is numerically analyzed to investigate the effect of inlet swirl on ignition time delay in scramjets. Combustion is treated using detail chemical kinetics. One-equation turbulence model of Spalart and Allmaras is chosen to study the problem and advection upstream splitting method is used as computational scheme. The results show that swirling both fuel and oxidizer streams may drastically decrease the ignition distance in supersonic combustion, unlike using the swirl just in fuel stream which has no helpful effect.

Keywords: Ignition delay, Supersonic combustion, Swirl, Numerical simulation, Turbulence.

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Authors: Ali Samadi Afshar, Hamed Harrafi, S.M.Javad Gharib Zahedi

Abstract:

IFP Group Technology “Sulfrex process" was used in Iran-s South Pars Gas Complex Refineries for removing sulfur compounds such as mercaptans, carbonyl sulfide and hydrogen sulfide, which uses sulfonated cobalt phthalocyanine dispersed in alkaline solution as catalyst. In this technology, catalyst and alkaline solution were used circularly. However the stability of catalyst due to effect of some parameters would reduce with the running of the unit and therefore sweetening efficiency would be decreased. Hence, the aim of this research is study the factors effecting on the stability of catalyst.

Keywords: sulfonated cobalt phthalocyanine, mercaptans, stability, catalyst, sulfur.

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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: Ahtesham Javaid, Costin S. Bildea

Abstract:

The design and plantwide control of an integrated plant where the endothermic 1,4-butanediol dehydrogenation and the exothermic furfural hydrogenation is simultaneously performed in a single reactor is studied. The reactions can be carried out in an adiabatic reactor using small hydrogen excess and with reduced parameter sensitivity. The plant is robust and flexible enough to allow different production rates of γ-butyrolactone and 2-methyl furan, keeping high product purities. Rigorous steady state and dynamic simulations performed in AspenPlus and AspenDynamics to support the conclusions.

Keywords: Dehydrogenation and hydrogenation, Reaction coupling, Design and control, Process integration.

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Authors: Sh. Shahhosseini, S. Alinia, M. Irani

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In this paper 2D Simulation of catalytic Fixed Bed Reactor in Fischer-Tropsch Synthesis of GTL technology has been performed utilizing computational fluid dynamics (CFD). Synthesis gas (a mixture of carbon monoxide and hydrogen) has been used as feedstock. The reactor was modeled and the model equations were solved employing finite volume method. The model was validated against the experimental data reported in literature. The comparison showed a good agreement between simulation results and the experimental data. In addition, the model was applied to predict the concentration contours of the reactants and products along the length of reactor.

Keywords: GTL, Fischer–Tropsch synthesis, Fixed Bed Reactor, CFD simulation.

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Authors: Srinivas Bathini, Duraichelvan Raju, Simona Badilescu, Muthukumaran Packirisamy

Abstract:

A bio-sensing method, based on the plasmonic property of gold nano-islands, has been developed for detection of exosomes in a clinical setting. The position of the gold plasmon band in the UV-Visible spectrum depends on the size and shape of gold nanoparticles as well as on the surrounding environment. By adsorbing various chemical entities, or binding them, the gold plasmon band will shift toward longer wavelengths and the shift is proportional to the concentration. Exosomes transport cargoes of molecules and genetic materials to proximal and distal cells. Presently, the standard method for their isolation and quantification from body fluids is by ultracentrifugation, not a practical method to be implemented in a clinical setting. Thus, a versatile and cutting-edge platform is required to selectively detect and isolate exosomes for further analysis at clinical level. The new sensing protocol, instead of antibodies, makes use of a specially synthesized polypeptide (Vn96), to capture and quantify the exosomes from different media, by binding the heat shock proteins from exosomes. The protocol has been established and optimized by using a glass substrate, in order to facilitate the next stage, namely the transfer of the protocol to a microfluidic environment. After each step of the protocol, the UV-Vis spectrum was recorded and the position of gold Localized Surface Plasmon Resonance (LSPR) band was measured. The sensing process was modelled, taking into account the characteristics of the nano-island structure, prepared by thermal convection and annealing. The optimal molar ratios of the most important chemical entities, involved in the detection of exosomes were calculated as well. Indeed, it was found that the results of the sensing process depend on the two major steps: the molar ratios of streptavidin to biotin-PEG-Vn96 and, the final step, the capture of exosomes by the biotin-PEG-Vn96 complex. The microfluidic device designed for sensing of exosomes consists of a glass substrate, sealed by a PDMS layer that contains the channel and a collecting chamber. In the device, the solutions of linker, cross-linker, etc., are pumped over the gold nano-islands and an Ocean Optics spectrometer is used to measure the position of the Au plasmon band at each step of the sensing. The experiments have shown that the shift of the Au LSPR band is proportional to the concentration of exosomes and, thereby, exosomes can be accurately quantified. An important advantage of the method is the ability to discriminate between exosomes having different origins.

Keywords: Exosomes, gold nano-islands, microfluidics, plasmonic biosensing.

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Authors: Maria D. Nikolaki, Katerina N. Zerva, Constantine. J. Philippopoulos

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The photochemical and photo-Fenton oxidation of 1,3-dichloro-2-propanol was performed in a batch reactor, at room temperature, using UV radiation, H2O2 as oxidant, and Fenton-s reagent. The effect of the oxidative agent-s initial concentration was investigated as well as the effect of the initial concentration of Fe(II) by following the target compound degradation, the total organic carbon removal and the chloride ion production. Also, from the kinetic analysis conducted and proposed reaction scheme it was deduced that the addition of Fe(II) significantly increases the production and the further oxidation of the chlorinated intermediates.

Keywords: 1, 3-dichloro-2-propanol, hydrogen peroxide, photo- Fenton, UV .

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Authors: H. Ganji, H. R. Mahdipoor, J. Ahmadpanah, H. Naderi

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The modified Claus process is the major technology for the recovery of elemental sulfur from hydrogen sulfide. The chemical reactions that can occur in the reaction furnace are numerous and many byproducts such as carbon disulfide and carbon carbonyl sulfide are produced. These compounds can often contribute from 20 to 50% of the pollutants and therefore, should be hydrolyzed in the catalytic converter. The inlet temperature of the first catalytic reactor should be maintained over than 250 °C, to hydrolyze COS and CS2. In this paper, the various configurations for the first converter reheating of sulfur recovery unit are investigated. As a result, the performance of each method is presented for a typical clause unit. The results show that the hot gas method seems to be better than the other methods.

Keywords: Sulfur recovery unit, reaction converter.

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Authors: Morteza Farahani, Ahmad Seif, Asadallah Boshra, Hossein Aghaie

Abstract:

Density functional theory (DFT) calculations were performed to calculate aluminum-27, boron-11, and nitrogen-14 quadrupole coupling constant (CQ) in the representative considered model of (6, 0) boron nitride-aluminum nitride nanotube junction (BN-AlNNT) for the first time. To this aim, 1.3 nm length of BNAlN consisting of 18 Al, 18 B, and 36 N atoms was selected where the end atoms capped by hydrogen atoms. The calculated CQ values for optimized BN-AlNNT system reveal different electrostatic environment in the mentioned system. The calculations were performed using the Gaussian 98 package of program.

Keywords: Nanotube Junction, Density functional, Nuclear Quadrupole Resonance.

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Authors: Sh. Shahhosseini, S. Alinia, M. Irani

Abstract:

In this work, axisymetric CFD simulation of fixed bed GTL reactor has been conducted, using computational fluid dynamics (CFD). In fixed bed CFD modeling, when N (tube-to-particle diameter ratio) has a large value, it is common to consider the packed bed as a porous media. Synthesis gas (a mixture of predominantly carbon monoxide and hydrogen) was fed to the reactor. The reactor length was 20 cm, divided to three sections. The porous zone was in the middle section of the reactor. The model equations were solved employing finite volume method. The effects of particle diameter, bed voidage, fluid velocity and bed length on pressure drop have been investigated. Simulation results showed these parameters could have remarkable impacts on the reactor pressure drop.

Keywords: GTL Process, Fixed bed reactor, Pressure drop, CFDsimulation.

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Authors: Javier Rivas, Olga Gimeno, Maria Carbajo, Teresa Borralho

Abstract:

The elimination of ranitidine (a pharmaceutical compound) has been carried out in the presence of UV-C radiation. After some preliminary experiments, it has been experienced the no influence of the gas nature (air or oxygen) bubbled in photolytic experiments. From simple photolysis experiments the quantum yield of this compound has been determined. Two photolytic approximation has been used, the linear source emission in parallel planes and the point source emission in spherical planes. The quantum yield obtained was in the proximity of 0.05 mol Einstein-1 regardless of the method used. Addition of free radical promoters (hydrogen peroxide) increases the ranitidine removal rate while the use of photocatalysts (TiO2) negatively affects the process.

Keywords: Quantum yield, photolysis, ranitidine, watertreatment.

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Authors: Shigenori Togashi, Kei Takenaka

Abstract:

We developed new processes which can collect and detect rapidly airborne pathogens such as the avian flu virus for the pandemic prevention. The fluorescence antibody technique is known as one of high-sensitive detection methods for viruses, but this needs up to a few hours to bind sufficient fluorescence dyes to viruses for detection. In this paper, we developed a mist-labeling can detect substitution viruses in a short time to improve the binding rate of fluorescent dyes and substitution viruses by the micro reaction process. Moreover, we developed the rapid detection system with the above “mist labeling”. The detection system set with a sampling bag collecting patient’s breath and a cartridge can detect automatically pathogens within 10 minutes.

Keywords: Viruses, Sampler, Mist, Detection, Fluorescent dyes, Microreaction.

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