Friday, 1 April 2016

IJOER: March 2016 Issue

Effect of losartan on functional and structural properties of conduit atery wall in young spontaneously hypertensive rats

Abstract The effect of losartan on systolic blood pressure (SBP), function and structure of thoracic aorta and mesenteric artery was examined. Four-week-old Wistar rats, spontaneously hypertensive rats (SHR), and SHR treated with losartan (20 mg/kg/day for 5 weeks) were used. SBP was measured by the tail-cuff method weekly. Isometric contraction of aortal rings and neurogenic contractions of mesenteric artery were studied in organ baths. For in vivo investigation after anesthesia, carotid artery was cannulated for SBP measurement and jugular vein for drug administration. Then thoracic aorta was processed according to electron microscopy procedure. In SHR (9-week-old) SBP and relative heart weight were increased, acetylcholine induced relaxation of phenylephrine-precontracted aortal rings was reduced compared to Wistar rats. In losartan treated SHR SBP and relative heart weight were lowered. Impairment of acetylcholine-induced relaxation was prevented and neurogenic responses of mesenteric artery were suppressed. In vivo administration of acetylcholine (0.1µg, 1µg, 10µg) evoked similar decrease of SBP in SHR and Wistar rats. In losartan treated SHR the decrease of SBP was larger than in SHR and Wistar rats. Wall thickness (WT) and cross-sectional area (CSA) of the aorta in SHR were decreased compared to Wistar rats; inner diameter (ID) and WT/ID ratio were not changed. In losartan treated SHR ID was increased and WT/ID decreased while WT and CSA were not changed. Conclusion: Losartan administered to SHR (i) reduced SBP, (ii) prevented impairment of endothelium-dependent relaxation, (iii) improved integrated responses to acetylcholine, and (iv) reduced structural changes in the aortic wall.

Keywords Hypertension, Conduit artery, Losartan, Neurogenic contraction, Structure.

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Modeling, Control and Steady State Analysis of Back To Back VSC HVDC System

Abstract— This paper proposes a dynamic model of a VSC (voltage source converter) based Back to Back HVDC system and its control technique. From the system model, the corresponding relationship between the controlling and the controlled variables of the VSC is determined. The vector control technique is used to control the working of converters. The control structure consists of outer control loop and inner control loop. The outer loop controller controls the active and reactive power separately. The inner loop controller which is a fast working controller provides the reference d- axis and q- axis voltages which are required by the PWM for generating the triggering pulse. The validity of the model and the feasibility of the control method have been proved by the simulation results. In this paper the system performance is studied under steady state condition.

Keywords— Inner loops Controller, outer loops Controller, Vector Control, VSC HVDC.

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Synthesis and characterization of PEO complexed with NaClO4 soluble base salt and Nb2O5 Nano-filler

Abstract Conducting solid phase polymer electrolyte (SPE) films were synthesized using solution casting method. The polyethylene oxide [PEO] complexed with an alkali salt sodium perchlorate [NaClO4] and nano-filler Nb2O5 with varying weight percentile [5%-15%] ratios. The complexation of NaClO4 salt with the polymer matrix PEO has been confirmed by XRD and surface morphology was understood by the SEM images and elemental composition was estimated by EDAX results. The AC conductivity measurements were done in the temperature range of 303K–343K using AC conductivity set up. The electrical conductivity shows an improvement and enhanced to fourth order. The conductivity in polymer electrolyte system is due to ions of alkaline salts and Nb2O5 nano-filler which are present in polymer matrix. Several electrical and dielectric characterizations were done for these films.

Keywords Activation Energy, Conductivity, Dielectric properties, Nanocomposite Polymer Electrolyte [NCPE], solution cast technique.

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Digital Filter Design of Infinite Impulse Response (IIR) Infrasound to Detect Fetal Heart Rate

Abstract One way of checking on a pregnant woman is inspection using ultrasonic wave Doppler technique, this check is done by putting Doppler ultrasonic waves over the abdomen to capture the heart beat of the fetus with the addition of the gel material, there sebaga in pregnant women who are allergic to the gel material. Alternatively we can use the technique in frassonik waves. With a digital design II Chebyshev band pass filter with a frequency range of 2-3Hz, the heart rate of pregnant women with fetal heart beat can be distinguished. With the help of software MatLab and Xilink will be resolved in the manufacture of digital filter terser but. The simulation results with the software quite satisfactory.

Keywords— heartbeat, infrasound.

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Surface characterization of ZnO:Al transparent thin films

Abstract We present the effect of hydrogen on surface characterization by Rf magnetron sputtered ZnO:Al thin films. ZnO:Al films are self textured and surface roughness of ZnO:Al films varies with H2 dilution ratio and ultimately affects on diffused transmittance varies from 41-27% with the variation of hydrogen (5-40%) with improved resistivity of 3.9×10-4 Ω-cm. The light scattering effect of hydrogen textured thin films was evaluated by the measurement of diffused transmittance. Experimental result shows that introduction of hydrogen effect significantly improved the light trapping in terms of diffuse transmittance without affecting electrical and other optical properties of ZnO:Al thin film.

Keywords ZnO:Al, RF magnetron sputtering, transparent conductive oxides, Atomic force microscope, Diffused Transmittance.

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Biodiesel Production by using CaO-Al2O3 Nano Catalyst

Abstract Because of biodegradability and non-toxicity biodiesel has become more attractive as alternative fuel. Biodiesel is produced mainly from vegetable oils by transesterification of triacylglycerols. From economic and social reasons, edible oils should be replaced by lower-cost and reliable feed stocks for biodiesel production such as non-edible plant oils. Biodiesel is considered an alternate and renewable substitute for petro-diesel. Pure vegetable oils and animal fats are being widely used for biodiesel production which is resulting in increased food cost and thus causing economic imbalance. In this research, inedible oils e.g. Jatropha oil is investigated for biodiesel production through transesterification process by using CaO-Al2O3 nanocatalyst, synthesized via top down technique. The synthesized nanoparticles were then characterized by XRD. The average crystallite size determined by XRD analysis was 29.9nm.It was calculated by using the Scherrer equation. These nanoparticles were tested to be used as a nanocatalyst for the production of biodiesel from Jatropha curcas oil. The fatty acid content of the oil and the biodiesel was analyzed using Gas Chromatography-Mass Spectroscopy (GC-MS). Propanoic acid (C5H10O3) was observed to be the most abundant compound present in methyl esters. Methanol to oil molar ratio of 3:1 and 5:1 were investigated for optimization process. The optimization results for production of biodiesel from the transesterification of Jatropha curcas oil catalyzed by CaO-Al2O3 nanoparticles showed maximum yield i.e. 82.3% at 5:1 methanol to oil molar ratio.

Keywords— Jatropha curcas oil, CaO Nanoparticles, Al2O3 Nanoparticles, biodiesel, Transesterification.

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Parameters and some applications of plasma generated during keyhole welding using a highly concentrated energy beam – an overview

Abstract Keyhole welding using concentrated energy beams (electron beam and laser beam) is at the forefront of welding technology and finding ways to improve welding quality is a pressing issue. Finding optimal welding modes, monitoring weld quality and/or detecting weld defects in real-time during the welding process using nondestructive, cost-effective and reliable methods is one of current challenges. Plasma generated in the keyhole and the plasma plume (space above the welding pool) provides an opportunity to study welding stability and optimal modes as well as formation of weld defects.

Generation and characteristics of plasma in the keyhole and above the welding pool are discussed in the paper. For laser keyhole welding spectral analysis data and video image techniques are widely used for control and inspection of laser induced plasma in real time. Electron beam welding is studied using plasma parameter measurements and by studying the current collected by the positively polarized ring electrode above the welding pool. In case of electron beam welding with beam oscillations the method of coherent accumulation is applicable to analyze of the plasma fluctuations process at the plasma electron current.

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Widths of Channel Routing in VLSI Design

AbstractIn VLSI design, one of the most important detailed routings is the channel routing. Given a channel with length n in 2-layer Manhattan model, Szeszler proved that the width (number of tracks required for routing) of the channel is at most 7/4n, and this upper bound can be achieved by a linear time algorithm. In this note, we improve the upper bound 7/4n to 3/2n, which also can be achieved by a linear time algorithm.

KeywordsChannel routing, Graph Theory, VLSI design.

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Hopf Bifurcation Analysis for the Comprehensive National Strength Model with Time Delay

Abstract This paper mainly modifies and further develops the comprehensive national strength model. By modifying the basic comprehensive national strength model, it can more accurately illustrate the society phenomena with time delay. First, we research the dynamics of the modified with time delay. By employing the normal form theory and center manifold method, we obtain some testable results on these issues. The conclusion confirms that a Hopf bifurcation occurs due to the existence of stability switches when the delay varies. Finally, some numerical simulations are given to illustrate the effectiveness of our result.

Keywords Hopf bifurcation, Stability, Comprehensive national strength model, Center manifold, Normal form.

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Anticorrosion behavior of deposited nanostructured polythiophene on stainless steel, carbon steel, and aluminum in sea water

Abstract In this study adherent films of polythiophene were deposited by electropolymerization of thyhiophene monomer ,onto stainless steel 316,carbon steel (C45), and aluminum (6061), the anticorrosion performance in artificial seawater (3.5% NaCl) solution were investigated at four temperatures, namely 20,30,40,50ᴼC using Tafel plots. The FTIR, XRD, TG, AFM, and SEM techniques, were used to evaluate the polythiophene deposited layer, they revealed nanofibers like structures with diameters around 40-50 nm , the thermal stability reach 300ᴼC.

Keywords polythiophene , electropolymerization , corrosion protection, nanostructure

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Clean Unit System Platform (CUSP) for Medical/Hygienic Applications

Abstract Analyzing conventional cleanrooms, we have proposed and demonstrated how well Clean Unit System Platform (CUSP) works. The CUSP serves as a clean versatile environment having low power-consumption and high cost-performance, and is suitable not only for processing the next generation new devices, but also for cross-disciplinary fields, including medical/hygienic applications. CUSP can provide us with dust- and microbe-free environment as good as US FED 209E class 10 in room-type CUSP, and class 1 with foldable CUSP (F-CUSP). Sleeping in F-CUSP has opened a window for Kinetosomnogram, which, based on the analysis of the peaks in the particle-count and the autocorrelation of them, would contribute to evaluation of sleep quality and/or sleep disorders. The F-CUSP as well as a capsule CUSP that operates with tiny FFU covering minimum volume can reduce the risk of MERS or other diseases mediated by air-borne microbes. With its full line-up, CUSP can outperform conventional super cleanrooms (“main frames”) and also provides us with environment suitable, especially, for those people under the risk of suffering from particulate matters (PM) 2.5, airborne microbes, or other foreign materials. The CUSP would be the clean space for all of us.

Keywords Clean environment, CUSP, kinetosomnogram, microbe-free environment, Tent-type CUSP (T-CUSP).

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PET-CT and CT Alone Comparison for Target Volume Definition in Radiation Treatment in Patients with Lung Cancer

Abstract

Purpose: The aim of this study was to evaluate the possible role of fused images (anatomical CT and functional FDG-PET), acquired with a combined PET-CT scanner, in delineating gross tumour volume (GTV) and clinical target volume (CTV).

Materials and Methods: Twenty-nine patients with small cell or non-small cell lung cancer were studied. CT and FDG-PET images were obtained in treatment position in a combined PET/CT scanner. FDG-PET and CT images were transferred to a workstation for contouring. Gross Tumor Volumes (GTV) and Clinical Target Volumes (CTV) were defined first using the CT data alone and then using the registered CT and FDG-PET data. For each patients two three Dimensional Conformal Radiotherapy (3DCRT) plans were made and they were compared with respect to the GTV, CTV, mean lung dose and volume of normal lung receiving ≥20 Gy (Vlung20Gy)

Results: Out of these 29 patients, PET clearly changed GTV in 17 patients. PET increased CTV in 7 patients. Additional unsuspected regional nodal disease was included in these patients. In 16 patients with atelectasis, decrease in CTV led to reduced radiation dose to the lung. Likewise, with additional PET information, CTV was enlarged and values of MLD and Vlung20Gy were increased in 5 patients.

Conclusion: The use of PET/CT images in radiotherapy is helpful in defining tumor location more precisely, possibly sparing more normal lung tissues and also helpful in differentiating tumor from atelectasis lung. The increasing availability of combined PET/CT units will facilitate the use of this technology for radiation treatment planning.

Keywords Lung Cancer, Image Fusion, PET/CT, Target Definition, Treatment Planning.

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Osteoclastic resorption and osteoinduction in the highly purified B-tricalcium phosphate implanted in the rat subcutaneous tissue are promoted by autologous bone marrow cells.

Abstract Sequential cellular events after highly purified b-tricalcium phosphate (b-TCP) implantation with or without rat bone marrow (BM) cells were investigated. b-TCP disks were soaked with BM cells harvested from femora of syngeneic rats, and were implanted into subcutis of the eight-week-old rats. Specimens were harvested in the intended stage and histological examinations were performed.

In BM-treated group, new bone formation was detected and intense signals of α1 chain of typeⅠ procollagen mRNA were expressed in osteoblasts after day 14. On day 56, new bone never degenerated and normal bone marrow tissue was observed. TRAP positive-multinucleated cells appeared after day 7 and cathepsinK-positive osteoclasts appeared after day 14 with directly attached to b-TCP. Conversely, in BM non-treated group, new bone formation was never observed even on day 56 and neither TRAP nor cathepsinK positive-osteoclast was detected in the whole stage. Quantitative analysis showed that b-TCP area decreased time-dependently in BM-treated group, but not in BM non-treated group. In conclusion, these findings indicate that b-TCP loaded with BM cells has osteoinductive ability. b-TCP is resorbed mainly by osteoclasts and this event promotes ectopic bone formation. BM cells play an important role in osteoinduction and osteoclast differentiation and function.

Keywords Bone marrow cells; Osteoinduction; Osteoclasts; b-tricalcium phosphate.

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New Hybrid Concatenated Codes

Abstract To improve the performance of hybrid concatenated convolutional codes (HCCC); a modified Log-MAP algorithm and an enhanced HCCC are introduced and demonstrated to be efficient and practical by simulation results. The new coding scheme achieves about 1.0 dB additional coding gain, compared to the general turbo coding scheme at a BER = 10-6, with a frame length of 8192-bit. The system complexity and decoding latency of the new scheme is lower than the HCCC proposed by Divsalar and Pollara [6] within acceptable performance degradation. Since the bit-error-rate of the proposed HCCC can be dramatically reduced by slightly increasing signal-to-noise ratio, the new hybrid concatenated coding scheme is very suitable for those communication environments in which high reliability is important.

Keywordshybrid concatenated convolutional codes (HCCC), bit-error-rate, coding gain.

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Design Approach for Trans –Sahara Gas Pipeline Transmission

Abstract Natural gas is poised to occupy a more prominent place in the global energy balance, coupled with other renewable energy sources, natural gas is an energy source of choice for the development of Africa and offers a vehicle for its integration with the world economy. The Economic Sustainability and expected benefits of Nigerian gas reserves are estimated at 5 trillion cubic meters – equal to roughly ten years of consumption of the EU. The modeling approach for long distance natural gas pipeline is optimized and design for the minimum installation cost. In this research paper the minimum cost for the installation of long gas pipeline is obtained by designing the different set of pipeline networks for which the installation costs are estimated and compared with the minimum capital cost. Various available pipeline systems are designed by varying the compressor station spacing for different standard pipe diameters. Accurate installation costs for each obtained pipeline network are estimated by using an advanced cost estimating computer program which uses real and updated data for the estimation. These total costs of the various pipeline networks are compared to obtain a minimum installation cost. The 1000km pipeline is divided into a number of short sections to calculate the pressure drop along the pipeline length. The design pressure is considered according to the 600 flange rating, 1,350 Psig and 90% of the design pressure is envisaged for the maximum operating pressure for the pipeline design.

Keywords Tran-Sahara, Transmission, Pipeline, Minimum cost.

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Evaluation of the Effect of Surface Preparation on Corrosion Properties of Cerametallic Composites in Titanium Matrix

Abstract Metal matrix composites reinforced ceramic particles, are widely used in industry, wherever high resistance to abrasive wear, erosion and corrosion is necessary. Cermets, in which titanium carbide (TiC) is used as reinforcing phase, are particularly interesting for improving the strength, stiffness and wear resistance, especially at elevated temperatures. The paper presents the results of corrosion tests of 316L stainless steel composite reinforced nc-TiC particles, at different stages of surface preparation: grinding, polishing, electropolishing and oxidation in the furnance. Measurements of potentiodynamic polarization curves in 3% NaCl solution were performed. The results have showed the negative impact of the nanocrystalline TiC strengthening phase on corrosion resistance of composites. It was also found that electropolishing treatment is the most preferred way to prepare the surface for 316L stainless steel as well as TiC reinforced composites.

Keywords Metal matrix composite, titanium, titanium carbide, corrosion resistance, SLM.

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Effect of Strontium concentration on the luminescent properties of (Ba1-xSrx)2SiO4:Eu2+ prepared by pressure-assisted combustion-synthesis

Abstract In this work, the effect of Sr doping concentration on the morphological and luminescence properties of Ba2SiO4:Eu2+ phosphors was studied. Green-yellow emitting phosphors (Ba1-xSrx)2SiO4 activated with Eu2+ ions were fabricated by pressure-assisted combustion synthesis (PACS) at an initial pressure of 3.4 MPa. The Sr (x) atomic concentration was changed from 0.0 to 0.5 at.%. The X-ray diffraction (XRD) analysis showed that these phosphors have a single phase corresponding to the Ba2SiO4 orthorhombic phase. Different morphologies with sizes in the range of 1-12.12 µm were observed according to the Sr content, such as spheres-like (x=0.0 at.%), irregular-shaped (x=0.2 at.%) and rectangular flakes-like particles (x=0.5 at.%).The main emission bands were located in the range of 507 to 522 nm, which correspond to 4f-5d allowed electric-dipole transition of Eu²+ and the main excitation band was located at 397 nm. The phosphor with flakes-like morphology (x=0.5 at.% of Sr) exhibited the highest luminescent intensity and its CIE coordinates are (0.31, 0.60) which color is located in the green region. The strong green-yellow emission observed in our phosphors suggests that they can be useful for the green component in RGB white LEDs.

Keywords (BaSr)2SiO4, combustion synthesis, luminescence, phosphors, white light-emitting diodes (WLEDs).

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Engineering Journal: October Issue 2017

TOC’S Five-Step Cycle: An Approach to Instant Results and Cultural Change Abstract — The Theory of Constraints (TOC) offers an interestin...