Search results for: phytochemical profile

Authors: N. Wongsai, R. Wetprasit, V. Siddoo

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The recently introduced ISO/IEC 29110 standard Lifecycle profile for Very Small Entities (VSE) has been adopted and practiced in many small and medium software companies, including in Thailand’s software industry. Many Thai companies complete their software process improvement (SPI) initiative program and have been certified. There are, however, a number of participants fail to success. This study was concerned with the factors that influence the accomplishment of the standard implementation in various VSE characteristics. In order to achieve this goal, exploring and extracting critical factors from prior studies were carried out and then the obtained factors were validated by the standard experts. Data analysis of comments and recommendations was performed using a qualitative content analysis method. This paper presents the initial set of influence factors in both positive and negative impact the ISO/IEC 29110 implementation with an aim at helping such SPI practitioners with some considerations to manage appropriate adoption approach in order to achieve its implementation.

Keywords: barriers, critical success factors, ISO/IEC 29110, Software Process Improvement, SPI, Very-Small Entity, VSE

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Authors: Zachary Muthii Rukenya, James Mbaria, Peter Mbaabu, Kiama Stephen Gitahi, Ronald Onzago

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Aloe turkanensis is one of the widely used medicinal shrub and in Kenya the plant is mainly found in Baringo, Isiolo, Laikipia, Turkana and West Pokot Counties where it is used in ethno-medicine and ethno-veterinary medicine. The Turkana community uses the plant products to manage malaria, wounds, stomach ache, constipation, pain, skin infection, poultry diseases and retained afterbirth in cows. This evaluated the efficacy and safety of the plant obtained from Turkana County, Kenya. Preliminary data on the use of the plant in the county was collected through observation, photographing and interviews. A sample of the whole plant was harvested in Natira sublocation, in ex-Turkana west district in February 2012 after identification by Aloe-working group herbalists who voluntarily provided information on its medicinal uses. Botanical identification was done at Kenya Forest Research Centre in Karura where voucher specimen was deposited. Cold maceration using 70% methanol and distilled water was used for extraction. Bioassays were to determine the effects of the plant extracts on brine shrimp and selected bacterial and fungal cultures. The extracts were tested in-vitro activity against standard cultures of B. cereus (ATCC 11778), S. aureus (ATCC25923), P. aeroginosa (ATCC 27853), E. coli (ATCC 25922) and a human infections clinical isolate of C. albicans. The extracts of Aloe turkanensis inhibited the growth B. cereus (100-200 mg/ml), S. aureus (50-100 mg/ml), P. aeroginosa (200mg/ml), E. coli (400mg/ml) while C. albicans was not affected. The extracts also inhibited the growth of S. aureus and B. cereus with mean diameters of inhibition zones being 19.75±1 mm and 18.5±05 mm reapectively. Phytochemical screening showed the presence of alkaloids, tarpenoids, steroids, quinones, saponins and tannins in the plant extracts. The extract was found to be non-toxic at a concentration of 1000µg/ml with a 100% survival of Brine Shrimp larva. It was concluded that Aloe turkanensis growing the study area has metabolites that inhibit the growth of microorganisms and is however, there is need for further studies to validate the in-vivo bioactivity of the plant and more generate adequate toxicological data.to support conservation, value chain addition of its products and widespread use as a herbal remedy.

Keywords: Aloe turkanensis, bioactivity, cultivated, human infections

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Authors: Alaa Mostafa, Samuel Dagogo-Jack, Vivian Thieu, Maria Yu, Nan Zhang, Dara Schuster, Luis-Emilio Garcia-Perez

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Dulaglutide (DU), a once-weekly glucagon-like peptide-1 receptor agonist, was studied in the AWARD clinical trial program in adult patients with type 2 diabetes (T2D) and demonstrated significant hemoglobin A1c (A1c) reduction and potential for weight loss. To evaluate the efficacy and safety of DU 1.5 mg and DU 0.75 mg in patients with T2D by baseline A1c <8.5% or ≥8.5%, a post-hoc analysis was conducted on AWARD-1 to -6 and -8 at 6 months. Across 7 studies, 55% to 82% of the DU-treated patients had a baseline A1c <8.5%, and 18% to 45% had a baseline A1c ≥8.5%. The ranges of A1c reductions with baseline A1c <8.5% and ≥8.5%, respectively, were: DU 1.5 mg: -0.67% to -1.25% and -1.22% to -2.37%; DU 0.75 mg: -0.53% to -1.07% and -1.37% to -2.19%. The A1c reduction from the pooled analysis was greater in patients with baseline A1c ≥8.5% than patients with baseline A1c <8.5%, respectively: DU 1.5 mg: -1.86% and -1.02%; DU 0.75 mg: -1.75% and -0.83%. DU treatments were well tolerated among baseline A1c subgroups. Across the AWARD program, DU 1.5 mg and DU 0.75 mg demonstrated significant A1c reduction in both subgroups with an acceptable safety profile. Compared to patients with baseline A1c <8.5%, patients with baseline A1c ≥8.5% had greater A1c reduction. Disclosures: This study was supported and conducted by Eli Lilly and Company, Indianapolis, IN, USA.

Keywords: A1c reduction, dulaglutide, type 2 diabetes, weight loss

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Authors: Nosheen Zareen Khan, Abdul Majeed Siddiqui, Muhammad Afzal Rana

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The steady flow of a second order fluid through constricted tube with slip velocity at wall is modeled and analyzed theoretically. The governing equations are simplified by implying no slip in radial direction. Based on Karman Pohlhausen procedure polynomial solution for axial velocity profile is presented. An expressions for pressure gradient, shear stress, separation and reattachment points and radial velocity are also calculated. The effect of slip and no slip velocity on velocity, shear stress, pressure gradient are discussed and depicted graphically. It is noted that when Reynolds number increases velocity of the fluid decreases in both slip and no slip conditions. It is also found that the wall shear stress, separation and reattachment points are strongly effected by Reynolds number.

Keywords: approximate solution, constricted tube, non-Newtonian fluids, Reynolds number

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Authors: Ajay Kumar, Neha Gupta

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

Keywords: biosensor, biomolecules, FinFET, sensitivity

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Authors: A. Chennai, M. Yahia, H. Boussenan

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Our study was designed to highlight changes in certain biochemical parameters such as (CH, TG, HDL, TGO, TGP, LDL, and CRP), hormones (FSH, LH, PRL, TSH, and leptin), in women who suffer from over weight and fertile controls as well as the research for potential pathophysiological link between obesity and infertility in this population of women. This practical work has been focused on a population of 24 over weight infertile women, compared to control subjects without any pathology causing disturbance parameters to be studied to determine the contribution of obesity in the etiology of infertility. The assay results revealed a highly significant difference between the two groups in the serum levels of CH, TG, HDL, and TGO TGP (P <0.0001) as well as the rate of LDL (p=0.0017) and CRP (p=0.02). Hormonal profile also shows a significant difference between the two groups (P<0.0001) for LH and leptin but no difference was found for serum TSH. A significant correlation between leptin and FSH, LH, and FSH, age and LH, PRL and age and between HDL and CRP. The present study suggests that obesity is associated with infertility, but no direct pathophysiological link between obesity and infertility has been determined. More in-depth studies are needed to determine the exact mechanism by which overweight leads to female infertility.

Keywords: fertility, obesity, hormones, biochemical, pathophysiological

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Authors: Christina Drosou, Konstantina E. Kyriakopoulou, Andreas Bimpilas, Dimitrios Tsimogiannis, Magdalini C. Krokida

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Rationale: Agiorgitiko is one of the most widely-grown and commercially well-established red wine varieties in Greece. Each year viticulture industry produces a large amount of waste consisting of grape skins and seeds (pomace) during a short period. Grapes contain polyphenolic compounds which are partially transferred to wine during winemaking. Therefore, winery wastes could be an alternative cheap source for obtaining such compounds with important antioxidant activity. Specifically, red grape waste contains anthocyanins and flavonols which are characterized by multiple biological activities, including cardioprotective, anti-inflammatory, anti-carcinogenic, antiviral and antibacterial properties attributed mainly to their antioxidant activity. Ultrasound assisted extraction (UAE) is considered an effective way to recover phenolic compounds, since it combines the advantage of mechanical effect with low temperature. Moreover, green solvents can be used in order to recover extracts intended for used in the food and nutraceutical industry. Apart from the extraction, pre-treatment process like drying can play an important role on the preservation of the grape pomace and the enhancement of its antioxidant capacity. Objective: The aim of this study is to recover natural extracts from winery waste with high antioxidant capacity using green solvents so they can be exploited and utilized as enhancers in food or nutraceuticals. Methods: Agiorgitiko grape pomace was dehydrated by air drying (AD) and accelerated solar drying (ASD) in order to explore the effect of the pre-treatment on the recovery of bioactive compounds. UAE was applied in untreated and dried samples using water and water: ethanol (1:1) as solvents. The total antioxidant potential and phenolic content of the extracts was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and Folin-Ciocalteu method, respectively. Finally, the profile of anthocyanins and flavonols was specified using HPLC-DAD analysis. The efficiency of processes was determined in terms of extraction yield, antioxidant activity, phenolic content and the anthocyanins and flavovols profile. Results & Discussion: The experiments indicated that the pre-treatment was essential for the recovery of highly nutritious compounds from the pomace as long as the extracts samples showed higher phenolic content and antioxidant capacity. Water: ethanol (1:1) was considered a more effective solvent on the recovery of phenolic compounds. Moreover, ASD grape pomace extracted with the solvent system exhibited the highest antioxidant activity (IC50=0.36±0.01mg/mL) and phenolic content (TPC=172.68±0.01mgGAE/g dry extract), followed by AD and untreated pomace. The major compounds recovered were malvidin3-O-glucoside and quercetin3-O-glucoside according to the HPLC analysis. Conclusions: Winery waste can be exploited for the recovery of nutritious compounds using green solvents such as water or ethanol. The pretreatment of the pomace can significantly affect the concentration of phenolic compounds, while UAE is considered a highly effective extraction process.

Keywords: agiorgitico grape pomace, antioxidants, phenolic compounds, ultrasound assisted extraction

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Authors: Mina Kargozari, Isabel Revilla Martin, Ángel A. Carbonell-Barrachina, Antoni Szumny

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The profiles of volatile compounds of differently formulated sausages including CH (camel meat-hump), CB (camel meat-beef fat), BH (beef-hump) and BB (beef-beef fat) were analyzed by gas chromatography/mass spectrometry (GC-MS) using a solid phase micro-extraction (SPME) in order to investigate the role of meat and fat type in aroma compounds release. A total of 47 compounds identified, were consisted of 3 acids, 1 ester, 3 alcohols, 7 aldehydes, 5 sulphur compounds, and 27 terpenes. The significant differences were observed in the aroma compounds among four batches. The CH sucuk samples containing the highest (p<0.05) fat amount among the others showed higher amounts of volatiles in consequence. The sausages prepared with hump showed higher amounts of aldehydes and lower amounts of terpenes compared to the sausages made with beef fat (p<0.05). It seemed that meat type had an inconsiderable effect on the volatile profile of the sausages.

Keywords: aromatic compounds, camel meat, hump, SPME

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Authors: Yufei Peng, Zhen Qin, Jianbe Li, Jidong Long

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The thermal cathode is widely used in accelerators, FELs and kinds of vacuum electronics. However, emission nonuniformity exists due to surface profile, material distribution, temperature variation, crystal orientation, etc., which will cause intrinsic emittance growth, brightness decline, envelope size augment, device performance deterioration or even failure. To understand how emittance is manipulated by emission nonuniformity, an intrinsic emittance model consisting of contributions from macro and micro surface nonuniformity is developed analytically based on general thermal emission model at temperature limited regime according to a real 3mm cathode. The model shows relative emittance increased about 50% due to temperature variation, and less than 5% from several kinds of micro surface nonuniformity which is much smaller than other research. Otherwise, we also calculated emittance growth combining with Monte Carlo method and PIC simulation, experiments of emission uniformity and emittance measurement are going to be carried out separately.

Keywords: thermal cathode, electron emission fluctuation, intrinsic emittance, surface nonuniformity, cathode lifetime

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Authors: J. O. Ezekwesili-Ofili, L. I. Okorafor, S. C. Nsofor

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Diabetes mellitus is a carbohydrate metabolism disorder due to an absolute or relative deficiency of insulin secretion, action or both. Many known hypoglycaemic drugs are known to produce serious side effects. However, the search for safer and more effective agents has shifted to plant products, including foods and spices. One of such is the rhizome of Curcuma longa or turmeric, which is a spice with high medicinal value. A drawback in the use of C. longa is the poor bioavailability of curcumin, the active ingredient. It has been reported that piperine, an alkaloid present in peppers increases the bioavailability of curcumin. This work therefore investigated the hypoglycaemic and antioxidant effects of ethanolic extract of C. longa rhizomes, alone and with two pepper adjuvants in alloxan-induced diabetic rats. A total of 48 rats were divided into 6 groups of 8 rats each. Groups A–E were induced with diabetes using 150mg/kg body weight of alloxan monohydrate, while group F was normoglycaemic: Group A: Diabetic; fed with 400 mg/g body weight of turmeric extract; group B: Diabetic, fed with 400 mg/kg b. w. and 200mg/kg b. w of ethanolic extract of seeds of Piper guinensee; group C: Diabetic, fed with 400 mg/kg b. w. and 200 mg /kg b. w. of ethanolic extract of seeds of Capsicum annum var cameroun, group D: Diabetic, treated with standard drug, glibenclamide (0.3mg/kg body weight), group E: Diabetic; no treatment i.e. Positive control and group F: non diabetic, no treatment i.e. Negative control. Blood glucose levels were monitored for 14 days using a glucometer. The levels of the antioxidant enzymes; glutathione peroxidase, catalase and superoxide dismutase were also assayed in serum. The ethanolic extracts of C. longa rhizomes at the dose given (400 mg/kg b. w) significantly reduced the blood glucose levels of the diabetic rats (p<0.05) comparable to the standard drug. Co administration of extract of the peppers did not significantly increase the efficiency of the extract, although C. annum var cameroun showed greater effect, though not significantly. The antioxidant effect of the extract was significant in diabetic rats. The use of piperine-containing peppers enhanced the antioxidant effect. Phytochemical analyses of the ethanolic extract of C. longa showed the presence of alkaloids, flavonoids, steroids, saponins, tannins, glycosides, and terpenoids. These results suggest that the ethanolic extract of C. longa had antidiabetic with antioxidant effects and could thus be of benefit in the treatment and management of diabetes as well as ameliorate pro-oxidant effects that may lead to diabetic complications. However, while the addition of piperine did not affect the antidiabetic effect of C. longa, the antioxidant effect was greatly enhanced.

Keywords: antioxidant, Curcuma longa rhizome, hypoglycaemic, pepper adjuvants, piperine

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Authors: Safia Akram

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The influence of nanofluid with different waveforms in the presence of inclined asymmetric channel on peristaltic transport of a pseudoplastic fluid is examined. The governing equations for two-dimensional and two directional flows of a pseudoplastic fluid along with nanofluid are modeled and then simplified under the assumptions of long wavelength and low Reynolds number approximation. The exact solutions for temperature and nanoparticle volume fraction are calculated. Series solution of the stream function and pressure gradient are carried out using perturbation technique. The flow quantities have been examined for various physical parameters of interest. It was found, that the magnitude value of the velocity profile decreases with an increase in volume flow rate (Q) and relaxation times (ζ) and increases in sinusoidal, multisinusoidal, trapezoidal and triangular waves. It was also observed that the size of the trapping bolus decreases with the drop of the width of the channel ‘d’ and increases with a rise of relaxation times ζ.

Keywords: nanofluid particles, peristaltic flow, pseudoplastic fluid, different waveforms, inclined asymmetric channel

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Authors: Ibrahim Cicek, Melike Nikbay

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Electrically propelled vehicles, either road or aerial vehicles are studied on contemporarily for their robust maneuvers and cost-efficient transport operations. The main power generating systems of such vehicles electrified by selecting proper components and assembled as e-powertrain. Generally, e-powertrain components selected considering the target performance requirements. Since the main component of propulsion is the drive unit, e-motor control system is subjected to achieve the performance targets. In this paper, the optimization of e-motor control parameters studied by Integral Squared Method (ISE). The overall aim is to minimize power consumption of such vehicles depending on mission profile and maintaining smooth maneuvers for passenger comfort. The sought-after values of control parameters are computed using the Optimal Control Theory. The system is modeled as a closed-loop linear control system with calibratable parameters.

Keywords: optimization, e-powertrain, optimal control, electric vehicles

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Authors: Samar Saadeldin Abdelmotalab Omer, Ikram Mohamed Eltayeb Elsiddig, Saad Mohammed Hussein Ayoub

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A variety of herbal medicinal plants are known to confer beneficial effects in regards to modification of cardiovascular ri’=sk factors. The anti-hypercholesterolaemic and antioxidant activities of the crude ethanolic extracts of Citrus reticulate fruit peel, Zingiber officinale rhizome and Sesamum indicum seed extracts have been demonstrated. These plants are assumed to possess biologically active principles, which impart their pharmacologic activities. GC-MS analysis of the ethanolic extracts was carried out to identify the active principles and their percentages of occurrence in the analytes. Analysis of the extracts was carried out using (GS-MS QP) type Schimadzu 2010 equipped with a capillary column RTX-50 (restec), (length 30mm, diameter 0.25mm, and thickness 0.25mm). Helium was used as a carrier gas, the temperature was programmed at 200°C for 5 minutes at a rate of 15ml/minute, and the extracts were injected using split injection mode. The identification of different components was achieved from their Mass Spectra and Retention time, compared with those in the NIST library. The results revealed the presence of 80 compounds in Sudanese locally grown C. reticulata fruit peel extract, most of which were monoterpenoid compounds including Limonene (3.03%), Alpha & Gamma - terpinenes (2.61%), Linalool (1.38%), Citral (1.72%) which are known to have profound antioxidant effects. The Sesquiterpenoids Humulene (0.26%) and Caryophyllene (1.97%) were also identified, the latter known to have profound anti-anxiety and anti-depressant activity in addition to the beneficiary effects in lipid regulation. The analysis of the locally grown S. indicum oily and water soluble portions of seed extract revealed the presence of a total of 64 compounds with considerably high percentage of the mono-unsaturated fatty acid ester methyl oleate (66.99%) in addition to methyl stearate (9.35%) and palmitate (15.71%) of oil portion, whereas, plant sterols including Gamma-sitosterol (13.5%), fucosterol (2.11%) and stigmasterol (1.95%) in addition to gamma-tocopherol (1.16%) were detected in extract water-soluble portion. The latter indicate various principles known to have valuable pharmacological benefits including antioxidant activities and beneficiary effects on intestinal cholesterol absorption and regulation of serum cholesterol levels. Z. officinale rhizome extract analysis revealed the presence of 93 compounds, the most abundant were alpha-zingeberine (16.5%), gingerol (9.25%), alpha-sesquiphellandrene (8.3%), zingerone (6.78%), beta-bisabolene (4.19%), alpha-farnesene (3.56%), ar-curcumene (3.29%), gamma-elemene (1.25%) and a variety of other compounds. The presence of these active principles reflected on the activity of the extract. Activity could be assigned to a single or a combination of two or more extract components. GC-MS analysis concluded the occurrence of compounds known to possess antioxidant activity and lipid profile effects.

Keywords: gas chromatography, indicum, officinale, reticulata

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Authors: hadi kargar, bahador shabani

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In this article, 16 cylinder motor combustion CFD modeling with a diameter of 165 mm and 195 mm along the way to help the FIRE software to optimize its function to work. A three-dimensional model of the processes that formed inside the cylinder made that involves mixing the fuel and air, ignition and spraying. In this three-dimensional model, all chemical species, density of air fuel spraying and spray with full profile intended to detailed results from mixing the fuel and air, igniting the ignition advance, spray, and mixed media in different times and get fit by moving the piston. Optimal selection of the model for the shape of the piston and spraying fuel specifications (including the management of spraying, the number of azhneh hole, start time of spraying and spraying angle) to achieve the best fuel consumption and minimal pollution. The spray hole 6 and 7 in three different configurations with five spraying and gives the best geometry and various performances in the simulation. 6 hole spray angle, finally spraying 72.5 degrees and two forms of spraying a better performance in comparison with other items of their own.

Keywords: spray, FIRE, CFD, optimize, diesel engine

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Authors: Y. M. Aiyesimi, G. T. Okedayo, O. W. Lawal

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The analysis has been carried out to study unsteady MHD thin film flow of a third grade fluid down an inclined plane with heat transfer when the slippage between the surface of plane and the lower surface of the fluid is valid. The governing nonlinear partial differential equations involved are reduced to linear partial differential equations using regular perturbation method. The resulting equations were solved analytically using method of separation of variable and eigenfunctions expansion. The solutions obtained were examined and discussed graphically. It is interesting to find that the variation of the velocity and temperature profile with the slip and magnetic field parameter depends on time.

Keywords: non-Newtonian fluid, MHD flow, thin film flow, third grade fluid, slip boundary condition, heat transfer, separation of variable, eigenfunction expansion

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Authors: D. He, Y. Pang, G. Lodewijks

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Belt conveyors play an important role in continuous dry bulk material transport, especially at the mining industry. Speed control is expected to reduce the energy consumption of belt conveyors. Transient operation is the operation of increasing or decreasing conveyor speed for speed control. According to literature review, current research rarely takes the conveyor dynamics in transient operation into account. However, in belt conveyor speed control, the conveyor dynamic behaviors are significantly important since the poor dynamics might result in risks. In this paper, the potential risks in transient operation will be analyzed. An existing finite element model will be applied to build a conveyor model, and simulations will be carried out to analyze the conveyor dynamics. In order to realize the soft speed regulation, Harrison’s sinusoid acceleration profile will be applied, and Lodewijks estimator will be built to approximate the required acceleration time. A long inclined belt conveyor will be studied with two major simulations. The conveyor dynamics will be given.

Keywords: belt conveyor , speed control, transient operation, dynamics

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Authors: Stuart W. Campbell, Alexander M. Galloway, Norman A. McPherson, Duncan Camilleri, Daniel Micallef

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Gas tungsten arc welding requires a gas shield to be present in order to protect the arc area from contamination by atmospheric gases. As a result of each gas having its own unique thermophysical properties, the shielding gas selected can have a major influence on the arc stability, welding speed, weld appearance and geometry, mechanical properties and fume generation. Alternating shielding gases is a relatively new method of discreetly supplying two different shielding gases to the welding region in order to take advantage of the beneficial properties of each gas, as well as the inherent pulsing effects generated. As part of an ongoing process to fully evaluate the effects of this novel supply method, a computational fluid dynamics model has been generated to include the gas dependent thermodynamic and transport properties in order to evaluate the effects that an alternating gas supply has on the arc plasma. Experimental trials have also been conducted to validate the model arc profile predictions.

Keywords: Alternating shielding gases, ANSYS CFX, Gas tungsten arc welding(GTAW), magnetohydrodynamics(MHD)

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Authors: Khaled Abou-El-Hossein

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The presentation will address the features of two IR convex lenses that have been manufactured using an ultra-high precision machining centre based on single-point diamond turning. The lenses are made from silicon and germanium with a radius of curvature of 500 mm. Because of the brittle nature of silicon and germanium, machining parameters were selected in such a way that ductile regime was achieved. The cutting speed was 800 rpm while the feed rate and depth cut were 20 mm/min and 20 um, respectively. Although both materials comprise a mono-crystalline microstructure and are quite similar in terms of optical properties, machining of silicon was accompanied with more difficulties in terms of form accuracy compared to germanium machining. The P-V error of the silicon profile was 0.222 um while it was only 0.055 um for the germanium lens. This could be attributed to the accelerated wear that takes place on the tool edge when turning mono-crystalline silicon. Currently, we are using other ranges of the machining parameters in order to determine their optimal range that could yield satisfactory performance in terms of form accuracy when fabricating silicon lenses.

Keywords: diamond turning, optical surfaces, precision machining, surface roughness

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Authors: Matej Komanec, Tomas Nemecek, Dmytro Suslov, Petr Chvojka, Stanislav Zvanovec

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Nonlinear phenomena in the near- and mid-infrared region are attracting scientific attention mainly due to the supercontinuum generation possibilities and subsequent utilizations for ultra-wideband applications like e.g. absorption spectroscopy or optical coherence tomography. Thulium-based fiber lasers provide access to high-power ultrashort pump pulses in the vicinity of 2000 nm, which can be easily exploited for various nonlinear applications. The paper presents a simulation and experimental study of a pulsed thulium laser based for near-infrared (NIR) and mid-infrared (MIR) nonlinear applications in specialty optical fibers. In the first part of the paper the thulium laser is discussed. The thulium laser is based on a gain-switched seed-laser and a series of amplification stages for obtaining output peak powers in the order of kilowatts for pulses shorter than 200 ps in full-width at half-maximum. The pulsed thulium laser is first studied in a simulation software, focusing on seed-laser properties. Afterward, a pre-amplification thulium-based stage is discussed, with the focus of low-noise signal amplification, high signal gain and eliminating pulse distortions during pulse propagation in the gain medium. Following the pre-amplification stage a second gain stage is evaluated with incorporating a thulium-fiber of shorter length with increased rare-earth dopant ratio. Last a power-booster stage is analyzed, where the peak power of kilowatts should be achieved. Examples of analytical study are further validated by the experimental campaign. The simulation model is further corrected based on real components – parameters such as real insertion-losses, cross-talks, polarization dependencies, etc. are included. The second part of the paper evaluates the utilization of nonlinear phenomena, their specific features at the vicinity of 2000 nm, compared to e.g. 1550 nm, and presents supercontinuum modelling, based on the thulium laser pulsed output. Supercontinuum generation simulation is performed and provides reasonably accurate results, once fiber dispersion profile is precisely defined and fiber nonlinearity is known, furthermore input pulse shape and peak power must be known, which is assured thanks to the experimental measurement of the studied thulium pulsed laser. The supercontinuum simulation model is put in relation to designed and characterized specialty optical fibers, which are discussed in the third part of the paper. The focus is placed on silica and mainly on non-silica fibers (fluoride, chalcogenide, lead-silicate) in their conventional, microstructured or tapered variants. Parameters such as dispersion profile and nonlinearity of exploited fibers were characterized either with an accurate model, developed in COMSOL software or by direct experimental measurement to achieve even higher precision. The paper then combines all three studied topics and presents a possible application of such a thulium pulsed laser system working with specialty optical fibers.

Keywords: nonlinear phenomena, specialty optical fibers, supercontinuum generation, thulium laser

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Authors: Jessemyn Modiini, Timothy Lynar, Elena Sitnikova

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We present a novel enhanced compartmental model for malware spread analysis in cyber security. This paper applies cyber security data features to epidemiological compartmental models to model the infectious potential of malware. Compartmental models are most efficient for calculating the infectious potential of a disease. In this paper, we discuss and profile epidemiologically relevant data features from a Domain Name System (DNS) dataset. We then apply these features to epidemiological compartmental models to network traffic features. This paper demonstrates how epidemiological principles can be applied to the novel analysis of key cybersecurity behaviours and trends and provides insight into threat modelling above that of kill-chain analysis. In applying deterministic compartmental models to a cyber security use case, the authors analyse the deficiencies and provide an enhanced stochastic model for cyber epidemiology. This enhanced compartmental model (SUEICRN model) is contrasted with the traditional SEIR model to demonstrate its efficacy.

Keywords: cybersecurity, epidemiology, cyber epidemiology, malware

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Authors: B. Safsaf, M. Tlidjane, B. Mamache, M. A. Dehimi, H. Boukrous, Aly A. Hassan

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The aim of this study is to determine the effect of age and physiological status on progesterone and energy metabolism of Ouled Djellal (O.D) breed ewes. 40 healthy ewes were divided into two groups, primiparous and multiparous, with 20 ewes in each group. The body weights (BW) (kg) were 46.6 ± 4.20 and 59.2 ± 3.02, and consuming less 25 to 30% of their basal energetic requirements. The values of serum glucose, triglycerides and cholesterol were lower in pregnant than in non-pregnant ewes. The high to very high significant differences were found during the 15th week of pregnancy for glycaemia and triglyceridemia respectively. Concerning serum progesterone, a very highly significant difference (p < 0.001) was noted in the pregnant group, and the values were higher in MP than in PP. After lambing, the triglyceridemia values were slightly lower in primiparous than in multiparous pregnant ewes. In order to prevent imbalance during critical periods of reproduction, we can use the serum metabolic profile.

Keywords: age, energy metabolites, ouled djellal breed ewes, physiologic status, progesterone

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Authors: Ezzeddin Anawa, Abdol-Ghane Olabi

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The dissimilar joint between aluminum /titanium alloys (Al 6082 and Ti G2) alloys were successfully achieved by CO2 laser welding with a single pass and without filler material using the overlap joint design. Laser welding parameters ranges combinations were experimentally determined using Taguchi approach with the objective of producing welded joint with acceptable welding profile and high quality of mechanical properties. In this study a joining of dissimilar Al 6082 / Ti G2 was result in three distinct regions fusion area (FA), heat-affected zone (HAZ), and the unaffected base metal (BM) in the weldment. These regions are studied in terms of its microstructural characteristics and microhardness which are directly affecting the welding quality. The weld metal was mainly composed of martensite alpha prime. In two different metals in the two different sides of joint HAZ, grain growth was detected. The microhardness of the joint distribution also has shown microhardness increasing in the HAZ of two base metals and a varying microhardness in fusion zone.

Keywords: microharness , microstructure, laser welding and dissimilar jointed materials.

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Authors: Yehya Abdellatif, Iyad M. Muslih, Azzah Alkhalailah, Abdallah Muslih

Abstract:

Hybrid Optimization Model for Electric Renewable (HOMER) software was utilized to find the optimum design of a hybrid off-Grid system, by choosing the optimal solution depending on the cost analysis of energy based on different capacity shortage percentages. A complete study for the site conditions and load profile was done to optimize the design and implementation of a hybrid off-grid power station. In addition, the solution takes into consecration the ambient temperature effect on the efficiency of the power generation and the economical aspects of selection depending on real market price. From the analysis of the HOMER model results, the optimum hybrid power station was suggested, based on wind speed, and solar conditions. The optimization function objective is to minimize the Net Price Cost (NPC) and the Cost of Energy (COE) with zero and 10 percentage of capacity shortage.

Keywords: energy modeling, HOMER, off-grid system, optimization

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Authors: Maryam Nejat Dehkordi, Per Lincoln, Hassan Momtaz

Abstract:

Interaction of Schiff base complexes of iron and manganese (iron [N, N’ Bis (5-(triphenyl phosphonium methyl) salicylidene) -1, 2 ethanediamine) chloride, [Fe Salen]Cl, manganese [N, N’ Bis (5-(triphenyl phosphonium methyl) salicylidene) -1, 2 ethanediamine) acetate) with DNA were investigated by spectroscopic and isothermal titration calorimetry techniques (ITC). The absorbance spectra of complexes have shown hyper and hypochromism in the presence of DNA that is indication of interaction of complexes with DNA. The linear dichroism (LD) measurements confirmed the bending of DNA in the presence of complexes. Furthermore, isothermal titration calorimetry experiments approved that complexes bound to DNA on the base of both electrostatic and hydrophobic interactions. Furthermore, ITC profile exhibits the existence of two binding phases for the complex. Antibacterial activity of ligand and complexes were tested in vitro to evaluate their activity against the gram positive and negative bacteria.

Keywords: Schiff base complexes, ct-DNA, linear dichroism (LD), isothermal titration calorimetry (ITC), antibacterial activity

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Authors: Cristiano Giordani, Marco Diociaiuti, Cecilia Bombelli, Laura Zanetti-Polzi, Marcello Belfiore, Raoul Fioravanti, Gianfranco Macchia

Abstract:

We investigated induced functional effects by evaluating Ca2+-influx in liposomes and cell viability in HT22-DIFF neurons. Only solutions rich in unstructured Prefibrillar-Oligomers (PFOs) were able, in the presence of Monosialoganglioside-GM1 (GM1), to induce Ca2+-influx and were also neurotoxic, suggesting a correlation between the two phenomena. Thus, in the presence of GM1, we investigated the protein conformation and liposome modification due to the interaction. Circular Dichroism showed that GM1 fostered the formation of β-structures and Energy Filtered-Transmission Electron Microscopy that PFOs formed “amyloid-channels” as reported for Aβ. We speculate that electrostatic forces occurring between the positive PFOs and negative GM1 drive the initial binding, while the hydrophobic profile of the flexible PFO is responsible for the subsequent pore formation. Conversely, the rigid β-structured mature/fibers (MFs) and proto-fibers (PFs) were unable to induce membrane damage and Ca2+- influx.

Keywords: amyloid proteins, neurotoxicity, lipid-rafts, GM1

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Authors: Abdusalam Sharf

Abstract:

In the oil and gas industries, one of the most important issues in drilling wells is understanding the behavior of a flow through an annulus gap in a vertical position, whose outer wall is stationary whilst the inner wall rotates. The main emphasis is placed on a comparison of experimental and computational investigations into the effects of the rotation speed of the inner pipe on the axial velocity profiles. The computational investigations were carried out by employing CFD software, and Gambit and Fluent. Three turbulence models were used: standard, RNG with enhanced wall treatment, and SST model. The profiles of the axial velocity had investigated at different rotation speeds of the inner pipe with three different volumetric flow rates. The comparison results showed that the calculations satisfactorily predict the qualitative features of the axial and swirl velocity profiles and the RNG model performs the best results.

Keywords: computational fluid dynamics (CFD), SST k−ω shear-stress transport (k−ω mode variant), RNG k–ε renormalisation group (k−ε mode variant), y+ dimensionless distance from wall

Procedia PDF Downloads 379

Authors: Jung-Ho Moon, Tae Kwon Ha

Abstract:

M2 steels, the typical Co-free high speed steel (HSS) possessing hardness level of 63~65 HRc, are most widely used for cutting tools. On the other hand, Co-containing HSS’s, such as M35 and M42, show a higher hardness level of 65~67 HRc and used for high quality cutting tools. In the fabrication of HSS’s, it is very important to control cleanliness and eutectic carbide structure of the ingot and it is required to increase productivity at the same time. Production of HSS ingots includes a variety of processes such as casting, electro-slag remelting (ESR), forging, blooming, and wire rod rolling processes. In the present study, electro-slag rapid remelting (ESRR) process, an advanced ESR process combined by continuous casting, was successfully employed to fabricate HSS billets of M2, M35, and M42 steels. Distribution and structure of eutectic carbides of the billets were analysed and cleanliness, hardness, and composition profile of the billets were also evaluated.

Keywords: high speed tool steel, eutectic carbide, microstructure, hardness, fracture toughness

Procedia PDF Downloads 445

Authors: Gangmin Li, Fan Yang

Abstract:

Personalized recommendation is crucial for any recommendation system. One of the techniques for personalized recommendation is to identify the intention. Traditional user intention identification uses the user’s selection when facing multiple items. This modeling relies primarily on historical behaviour data resulting in challenges such as the cold start, unintended choice, and failure to capture intention when items are new. Motivated by recent advancements in Large Language Models (LLMs) like ChatGPT, we present an approach for user intention identification by embracing LLMs with Chain-of-Thought (CoT) prompting. We use the initial user profile as input to LLMs and design a collection of prompts to align the LLM's response through various recommendation tasks encompassing rating prediction, search and browse history, user clarification, etc. Our tests on real-world datasets demonstrate the improvements in recommendation by explicit user intention identification and, with that intention, merged into a user model.

Keywords: personalized recommendation, generative user modelling, user intention identification, large language models, chain-of-thought prompting

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Authors: Burcu Oralhan, Zeki Oralhan, Nilsun Sariyer, Kumru Uyar

Abstract:

Data mining has been becoming more and more important and a wide range of applications in recent years. Data mining is the process of find hidden and unknown patterns in big data. One of the applied fields of data mining is Customer Relationship Management. Understanding the relationships between products and customers is crucial for every business. Customer Relationship Management is an approach to focus on customer relationship development, retention and increase on customer satisfaction. In this study, we made an application of a data mining methods in telecommunication customer relationship management side. This study aims to determine the customers profile who likely to leave the system, develop marketing strategies, and customized campaigns for customers. Data are clustered by applying classification techniques for used to determine the churners. As a result of this study, we will obtain knowledge from international telecommunication industry. We will contribute to the understanding and development of this subject in Customer Relationship Management.

Keywords: customer churn analysis, customer relationship management, data mining, telecommunication industry

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Authors: Prasenjit Singha, Sunil Yadav, Soumya Ranjan Mohantry, Ajay Kumar Shukla

Abstract:

Temperature distribution in the hematite ore mixed with 7.5% coal was predicted by solving a 1-D heat conduction equation using an implicit finite difference approach. In this work, it was considered a square slab of 20 cm x 20 cm, which assumed the coal to be uniformly mixed with hematite ore. It was solved the equations with the use of MATLAB 2018a software. Heat transfer effects in this 1D dimensional slab convective and the radiative boundary conditions are also considered. Temperature distribution obtained inside hematite slab by considering microwave heating time, thermal conductivity, heat capacity, carbon percentage, sample dimensions, and many other factors such as penetration depth, permittivity, and permeability of coal and hematite ore mixtures. The resulting temperature profile can be used as a guiding tool for optimizing the microwave-assisted carbothermal reduction process of hematite slab was extended to other dimensions as well, viz., 1 cm x 1 cm, 5 cm x 5 cm, 10 cm x 10 cm, 20 cm x 20 cm. The model predictions are in good agreement with experimental results.

Keywords: hematite ore, coal, microwave processing, heat transfer, implicit method, temperature distribution

Procedia PDF Downloads 169