Search results for: sorption characteristics

Authors: Ahmed A. El-Gindy, Elham S. El-Nashar, Abdallah Nafaa, Sameh El-Kafrawy

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The generation of energy from marine energy became one of the most preferable resources since it is a clean source and friendly to environment. Egypt has long shores along Mediterranean with important cities that need energy resources with significant wave energy. No detailed studies have been done on wave energy distribution in the Egyptian waters. The objective of this paper is to assess the energy wave power available in the Egyptian waters for the choice of the most suitable devices to be used in this area. This paper deals the characteristics and power of the offshore waves in the Egyptian waters. Since the field observations of waves are not frequent and need much technical work, the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis data in Mediterranean, with a grid size 0.75 degree, which is a relatively course grid, are considered in the present study for preliminary assessment of sea waves characteristics and power. The used data covers the period from 2012 to 2014. The data used are significant wave height (swh), mean wave period (mwp) and wave direction taken at six hourly intervals, at seven chosen stations, and at grid points covering the Egyptian waters. The wave power (wp) formula was used to calculate energy flux. Descriptive statistical analysis including monthly means and standard deviations of the swh, mwp, and wp. The percentiles of wave heights and their corresponding power are done, as a tool of choice of the best technology suitable for the site. The surfer is used to show spatial distributions of wp. The analysis of data at chosen 7 stations determined the potential of wp off important Egyptian cities. Offshore of Al Saloum and Marsa Matruh, the highest wp occurred in January and February (16.93-18.05) ± (18.08-22.12) kw/m while the lowest occurred in June and October (1.49-1.69) ± (1.45-1.74) kw/m. In front of Alexandria and Rashid, the highest wp occurred in January and February (16.93-18.05) ± (18.08-22.12) kw/m while the lowest occurred in June and September (1.29-2.01) ± (1.31-1.83) kw/m. In front of Damietta and Port Said, the highest wp occurred in February (14.29-17.61) ± (21.61-27.10) kw/m and the lowest occurred in June (0.94-0.96) ± (0.71-0.72) kw/m. In winter, the probabilities of waves higher than 0.8 m in percentage were, at Al Saloum and Marsa Matruh (76.56-80.33) ± (11.62-12.05), at Alexandria and Rashid (73.67-74.79) ± (16.21-18.59) and at Damietta and Port Said (66.28-68.69) ± (17.88-17.90). In spring, the percentiles were, at Al Saloum and Marsa Matruh, (48.17-50.92) ± (5.79-6.56), at Alexandria and Rashid, (39.38-43.59) ± (9.06-9.34) and at Damietta and Port Said, (31.59-33.61) ± (10.72-11.25). In summer, the probabilities were, at Al Saloum and Marsa Matruh (57.70-66.67) ± (4.87-6.83), at Alexandria and Rashid (59.96-65.13) ± (9.14-9.35) and at Damietta and Port Said (46.38-49.28) ± (10.89-11.47). In autumn, the probabilities were, at Al Saloum and Marsa Matruh (58.75-59.56) ± (2.55-5.84), at Alexandria and Rashid (47.78-52.13) ± (3.11-7.08) and at Damietta and Port Said (41.16-42.52) ± (7.52-8.34).

Keywords: distribution of sea waves energy, Egyptian Mediterranean waters, waves characteristics, waves power

Procedia PDF Downloads 191

Authors: Olivine Lo

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Small- and Medium-Sized Enterprises (SMEs) consist of a broad variety of businesses, ranging from small grocery shops to manufacturing concerns. Some are dynamic and innovative, while others are more traditional. The definition of SMEs varies by country but is most determined by the number of employees, though business assets and sales revenues are alternative measures. There are eight main types of SME industries in Hong Kong: garment, electronics, plastics, metal and machinery, trading and logistics, building, manufacturing, and service industries. Information exchange is a key goal of human communication, and communicators have used a variety of media to maintain relationships through traditional face-to-face interactions and written forms like letters and faxes. With the advancement of mediated-interpersonal communication media from telephone to synchronic online tools like email, instant messaging, voice messaging, and video conferencing for sustaining relationships, particularly enabling geographically distanced relationships. Although these synchronous tools are gaining popularity, they are facilitating relationship maintenance in everyday life and complementing rather than replacing the more conventional face-to-face interactions. This study will test if there are any variances in effects by industry type among Hong Kong SMEs. The competitiveness of the business environment refers to the competition faced by a business within its particular industry. The more intense the competition in a given sector, the greater the potential for strategic uses of specific needs in a business. Both internal organization characteristics and external environments may affect firm performance and financial resources. The level of competitiveness within an industry will be a more reliable indicator to show how Hong Kong SMEs are striving to achieve their business goals using different techniques in their communication media preferences, rather than mere classification by industry type. This study thus divides the competitiveness of the business environment into internal and external: (1) the internal environment competition is the inherent competitiveness of the products or services provided by the SMEs, whereas (2) the external environment competition includes the economic and political realities and competitors joining the market. This study will test various organizational characteristics and competitiveness of the business environment to predict entrepreneurs’ communication media preferences.

Keywords: competitiveness of business environment, small- and medium-sized enterprises, organizational characteristics, communication media preference

Procedia PDF Downloads 30

Authors: Ercan Ceyhan, Ali Kahraman, Hasan Dalgıç

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This research was made during the 2011 and 2012 growing periods according to “Randomized Blocks Design” with 3 replications. Research material was the following chickpea genotype: CA119, CA128, CA149, CA150, CA222, CA250, CA254 and other 2 commercial varieties named as Gökçe and Yaşa. Some agronomical characteristics such as plant height (cm), number of pod per plant, number of seed per pod, number of seed per plant, 1000 seed weight (g) and seed yield (kg ha-1) were determined. Statistically significant variations were found amongst the genotypes for all variables except seeds per pod. Means of the two years showed the range for plant height was from 52.83 cm (Gökçe) to 73.00 cm (CA150), number of pod per plant was from 14.00 (CA149) to 26.83 (CA261), number of seed per pod was from 1.10 (Gökçe) to 1.19 (CA149 ve CA250), number of seed per plant was from 16.28 (CA149) to 31.65 (CA261), 1000 seed weight was from 295.85 g (CA149) to 437.80 g (CA261) and seed yield was from 1342.73 kg ha-1 (CA261) to 2161.50 kg ha-1 (CA128). Results of the research implicated that the new developed lines were superior compared with the control (commercial) varieties by means of most of the characteristics.

Keywords: agricultural characters, chickpea, seed yield, genotype variations

Procedia PDF Downloads 217

Authors: Hossein Shokouhmand, Masoomeh Shadab, Rohallah Torabi

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Turbulent flow inside the seal chamber of a pump operating at nearly high Reynolds number is investigated. A comparison of a 3-D computational model for flow and thermal analysis of a mechanical seal with experimental thermal results is presented. The computational model adequately predicts the flow field in the seal chamber and thermal characteristics with the rotating and stationary rings and the twister flow around the seal parts by solving N-S and energy equations in ANSYS-CFX software. The Reynolds stress model (RSM) is applied as a turbulence model for this purpose. Experimental work is discussed which quantifies the temperature of five different points of the working fluid in chamber, mass flow at inlet and the fluid pressure at inlet and outlet. Experimental measurements are combined with computational modeling to obtain local and average heat transfer characteristics. Numerical results of three cases including different flush rates are reported.

Keywords: mechanical seal, CFD_CFX, reynolds stress model, flow field, heat transfer analysis, stream line, heat transfer coefficient, heat flux, nusselt

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Authors: Tanima Chowdhury, Sanjay Chattopadhaya, Narayan Ch. Saha

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Khoa is an indigenous heat desiccated milk product having very poor shelf life. At ambient condition, shelf-life of khoa is normally only 2 days. The aim of present study was to determine the effect of benzoic acid as preservative as well as modified atmosphere packaging (MAP) technology to enhance shelf life of khoa at 27±2°C and 65% RH. During storage, analysis of chemical, sensory as well as microbiological characteristics were taken into consideration to mark distinguishable changes between the package of modified atmosphere technology (MAP) and ordinarily packed khoa (with and without preservative) samples. The results indicated a significant decrease of moisture content, pH and sensory scores and increase in titratable acidity, standard plate count and yeast and mould count during storage, irrespective of the type of packaging conditions. However, the rate of changes in characteristics of product packed in modified atmosphere was found to be slow. The storage study indicated that the khoa packed in ordinary packaging, with and without preservative, was acceptable for 4 and 8 days, respectively, whereas for modified atmosphere packed samples, it was consumable up to 8 and 12 days, respectively.

Keywords: benzoic acid, khoa, modified atmosphere packaging, shelf life

Procedia PDF Downloads 316

Authors: Sudaff Mohammed, Wahda Shuker Al-Hinkawi, Nada Abdulmueen Hasan

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The compatibility of the Rhizome and Complex Adaptive system theory as a strategy within the urban context is the essential interest of this paper since there are only a few attempts to establish a hybrid, multi-scalar, and developable strategy based on the concept of the Rhizome and the CAS theory. This paper aims to establish a Rhizomic CAS strategy for different urban contexts by investigating the principles, characteristics, properties, and mechanisms of Rhizome and Complex Adaptive Systems. The research focused mainly on analyzing three properties: aggregation, non-linearity, and flow through the lens of Rhizome, Rhizomatization of CAS properties. The most intriguing result is that the principal and well-investigated characteristics of Complex Adaptive systems can be ‘Rhizomatized’ in two ways; highlighting commonalities between Rhizome and Complex Adaptive systems in addition to using Rhizome-related concepts. This paper attempts to emphasize the potency of the Rhizome as an apparently stochastic and barely anticipatable structure that can be developed to analyze cities of distinctive contexts for formulating better customized urban strategies.

Keywords: rhizome, complex adaptive system (CAS), system Theory, urban system, rhizomatic CAS, assemblage, human occupation impulses (HOI)

Procedia PDF Downloads 42

Authors: Marine Reymond, Michael Descostes, Marie Muguet, Clemence Besancon, Martine Leermakers, Catherine Beaucaire, Sophie Billon, Patricia Patrier

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²²⁶Ra is one of the radionuclides resulting from the disintegration of ²³⁸U. Due to its half-life (1600 y) and its high specific activity (3.7 x 1010 Bq/g), ²²⁶Ra is found at the ultra-trace level in the natural environment (usually below 1 Bq/L, i.e. 10-13 mol/L). Because of its decay in ²²²Rn, a radioactive gas with a shorter half-life (3.8 days) which is difficult to control and dangerous for humans when inhaled, ²²⁶Ra is subject to a dedicated monitoring in surface waters especially in the context of uranium mining. In natural waters, radionuclides occur in dissolved, colloidal or particular forms. Due to the size of colloids, generally ranging between 1 nm and 1 µm and their high specific surface areas, the colloidal fraction could be involved in the transport of trace elements, including radionuclides in the environment. The colloidal fraction is not always easy to determine and few existing studies focus on ²²⁶Ra. In the present study, a complete multidisciplinary approach is proposed to assess the colloidal transport of ²²⁶Ra. It includes water sampling by conventional filtration (0.2µm) and the innovative Diffusive Gradient in Thin Films technique to measure the dissolved fraction (<10nm), from which the colloidal fraction could be estimated. Suspended matter in these waters were also sampled and characterized mineralogically by X-Ray Diffraction, infrared spectroscopy and scanning electron microscopy. All of these data, which were acquired on a rehabilitated former uranium mine, allowed to build a geochemical model using the geochemical calculation code PhreeqC to describe, as accurately as possible, the colloidal transport of ²²⁶Ra. Colloidal transport of ²²⁶Ra was found, for some of the sampling points, to account for up to 95% of the total ²²⁶Ra measured in water. Mineralogical characterization and associated geochemical modelling highlight the role of barite, a barium sulfate mineral well known to trap ²²⁶Ra into its structure. Barite was shown to be responsible for the colloidal ²²⁶Ra fraction despite the presence of kaolinite and ferrihydrite, which are also known to retain ²²⁶Ra by sorption.

Keywords: colloids, mining context, radium, transport

Procedia PDF Downloads 156

Authors: Cho-Liang Chung

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Uniform and rapid drug release are important for trauma dressing application. Low glass transition polymer system and non-woven nanofiber structures as the designs conduct rapid-release characteristics. In this study, polyvinylpyrrolidone, polysulfone, and polystyrene were dissolved in dimethylformamide to form precursor solution. These solutions were blended with vitamin C to form the electrospinning solutions. The non-woven nanofibers structures were successfully prepared using an electrospinning process. The following instruments were used to analyze the characteristics of non-woven nanofibers structures: Atomic force microscopy (AFM), Field Emission Scanning Electron Microscope (FE-SEM), and X-ray Diffraction (XRD). The AFM was used to scan the nanofibers. 3D Graphics were applied to explore the surface morphology of nanofibers. FE-SEM was used to explore the morphology of non-woven structures. XRD was used to identify crystal structures in the non-woven structures. The evolution of morphology of non-woven structures was changed dramatically in different durations, because of the moisture absorption and decreasing glass transition temperature; the non-woven nanofiber structures can be applied to uniform and rapid drug release for trauma dressing application.

Keywords: nanofibers, non-woven, electrospinning process, rapid drug releasing

Procedia PDF Downloads 139

Authors: S. P. Praveen Kumar, Bong-Su Sin, Kwon-Hee Lee

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Finned-tube heat exchangers are predominantly used in space conditioning systems, as well as other applications requiring heat exchange between two fluids. The design of finned-tube heat exchangers requires the selection of over a dozen design parameters by the designer such as tube pitch, tube diameter, tube thickness, etc. Finned-tube heat exchangers are common devices; however, their performance characteristics are complicated. In this paper, numerical studies have been carried out to analyze the performances of finned tube heat exchanger (without fins considered for experimental purpose) by predicting the characteristics of temperature difference and pressure drop. In this study, a design considering 5 design variables, maximizing the temperature difference and minimizing the pressure drop was suggested by applying DOE. In this process, L18 orthogonal array was adopted. Parametric analytical studies have been carried out using Analysis of Variance (ANOVA) to determine the relative importance of each variable with respect to the temperature difference and the pressure drop. Following the results, the final design was suggested by predicting the optimum design therefore confirming the optimized condition.

Keywords: heat exchanger, fluid analysis, heat transfer, design of experiment, analysis of variance

Procedia PDF Downloads 446

Authors: Jaqueline Maria Ribeiro Vieira

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Different strategies and tools are available at the oil and gas industry for detecting and analyzing tension and possible fractures in borehole walls. Most of these techniques are based on manual observation of the captured borehole images. While this strategy may be possible and convenient with small images and few data, it may become difficult and suitable to errors when big databases of images must be treated. While the patterns may differ among the image area, depending on many characteristics (drilling strategy, rock components, rock strength, etc.). Previously we developed and proposed a novel strategy capable of detecting patterns at borehole images that may point to regions that have tension and breakout characteristics, based on segmented images. In this work we propose the inclusion of data-mining classification strategies in order to create a knowledge database of the segmented curves. These classifiers allow that, after some time using and manually pointing parts of borehole images that correspond to tension regions and breakout areas, the system will indicate and suggest automatically new candidate regions, with higher accuracy. We suggest the use of different classifiers methods, in order to achieve different knowledge data set configurations.

Keywords: image segmentation, oil well visualization, classifiers, data-mining, visual computer

Procedia PDF Downloads 303

Authors: Greg Zimmerman

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Background: Major depression is a common illness that affects millions of people globally. It is the leading cause of disability and is projected to become the number one cause of the global burden of disease by 2030. Many of those who suffer from depression also suffer from Irritable Bowel Syndrome (IBS). Acupuncture has been shown to help depression. The aim of this study was to investigate the effectiveness of acupuncture in reducing the risk of IBS in patients with depression. Methods: We enrolled patients diagnosed with depression through the Taiwanese National Health Insurance Research Database (NHIRD). Propensity score matching was used to match equal numbers (n=32971) of the acupuncture cohort and no-acupuncture cohort based on characteristics including sex, age, baseline comorbidity, and medication. The Cox regression model was used to compare the hazard ratios (HRs) of IBS in the two cohorts. Results: The basic characteristics of the two groups were similar. The cumulative incidence of IBS was significantly lower in the acupuncture cohort than in the no-acupuncture cohort (Log-rank test, p<0.001). Conclusion: The results provided real-world evidence that acupuncture may have a beneficial effect on IBS risk reduction in patients with depression.

Keywords: acupuncture, depression, irritable bowel syndrome, national health insurance research database, real-world evidence

Procedia PDF Downloads 106

Authors: Maria E. Fortună, Elena Ungureanu, Răzvan Rotaru, Valeria Harabagiu

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Polymers are used in a variety of areas due to their unique mechanical and chemical properties. Natural polymers are biodegradable, whereas synthetic polymers are rarely biodegradable but can be modified. As a result, by combining the benefits of natural and synthetic polymers, composite materials that are biodegradable can be obtained with potential for biomedical and environmental applications. However, because of their strong resistance to degradation, it may be difficult to eliminate waste. As a result, interest in developing biodegradable polymers has risen significantly. This research involves obtaining and characterizing two biodegradable poly-ε-caprolactone-polydimethylsiloxane copolymers. A comparison study was conducted using an aminopropyl-terminated polydimethylsiloxane macroinitiator with two distinct molecular weights. The copolymers were obtained by ring-opening polymerization of poly (ɛ-caprolactone) in the presence of aminopropyl-terminated polydimethylsiloxane as initiator and comonomers and stannous 2-ethylhexanoate as a catalyst. The materials were characterized using a number of techniques, including NMR, FTIR, EDX, SEM, AFM, and DSC. Additionally, the water contact angle and water vapor sorption capacity were assessed. Furthermore, the copolymers were examined for environmental susceptibility by conducting biological tests on tomato plants (Lypercosium esculentum), with an accent on biological stability and metabolism. Subsequent to the copolymer's degradation, the dynamics of nitrogen experience evolutionary alterations, validating the progression of the process accompanied by the liberation of organic nitrogen. The biological tests performed (germination index, average seedling height, green and dry biomass) on Lypercosium esculentum, San Marzano variety tomato plants in direct contact with the copolymer indicated normal growth and development, suggesting a minimal toxic effect and, by extension, compatibility of the copolymer with the environment. The total chlorophyll concentration of plant leaves in contact with copolymers was determined, considering the pigment's critical role in photosynthesis and, implicitly, plant metabolism and physiological state.

Keywords: biodegradable, biological stability, copolymers, polydimethylsiloxane

Procedia PDF Downloads 22

Authors: Yong Min You

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The study on the torque ripple of Permanent Magnet Synchronous Motors (PMSMs) has been rapidly progressed, which effects on the noise and vibration of the electric vehicle. There are several ways to reduce torque ripple, which are the increase in the number of slots and poles, the notch of the rotor and stator teeth, and the skew of the rotor and stator. However, the conventional methods have the disadvantage in terms of material cost and productivity. The demagnetization characteristic of PMSMs must be attained for electric vehicle application. Due to rare earth supply issue, the demand for Dy-free permanent magnet has been increasing, which can be applied to PMSMs for the electric vehicle. Dy-free permanent magnet has lower the coercivity; the demagnetization characteristic has become more significant. To improve the torque ripple as well as the demagnetization characteristics, which are significant parameters for electric vehicle application, an unequal air-gap model is proposed for a PMSM. A shape optimization is performed to optimize the design variables of an unequal air-gap model. Optimal design variables are the shape of an unequal air-gap and the angle between V-shape magnets. An optimization process is performed by Latin Hypercube Sampling (LHS), Kriging Method, and Genetic Algorithm (GA). Finite element analysis (FEA) is also utilized to analyze the torque and demagnetization characteristics. The torque ripple and the demagnetization temperature of the initial model of 45kW PMSM with unequal air-gap are 10 % and 146.8 degrees, respectively, which are reaching a critical level for electric vehicle application. Therefore, the unequal air-gap model is proposed, and then an optimization process is conducted. Compared to the initial model, the torque ripple of the optimized unequal air-gap model was reduced by 7.7 %. In addition, the demagnetization temperature of the optimized model was also increased by 1.8 % while maintaining the efficiency. From these results, a shape optimized unequal air-gap PMSM has shown the usefulness of an improvement in the torque ripple and demagnetization temperature for the electric vehicle.

Keywords: permanent magnet synchronous motor, optimal design, finite element method, torque ripple

Procedia PDF Downloads 274

Authors: Roike Iwan Montolalu, Henny Adeleida Dien, Feny Mentang, Kristhina P. Rahael, Tomy Moga, Ayub Meko, Siegfried Berhimpon

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In the last 20 years, packaging materials derived from petrochemicals polymers were widely used as packaging materials. This due to various advantages such as flexible, strong, transparent, and the price is relatively cheap. However, the plastic polymer also has various disadvantages, such as the transmission monomer contamination into the material to be packed, and waste is non-biodegradable. Edible film (EF) is an up to date materials, generated after the biodegradable packaging materials. The advantages of the EF materials, is the materials can be eat together with food, and the materials can be applied as a coating materials for a widely kind of foods especially snack foods. The aims of this research are to produce and to analyze the characteristics of smoked EF made from carrageenan, myofibril and collagen of Black Marlin (Makaira indica) industrial waste. Smoked EF made with an addition of 0.8 % smoke liquid. Three biopolymers i.e. carrageenan, myofibril, and collagen were used as treatments, and homogenate for 1 hours at speed of 1500 rpm. The analysis carried out on the pH and physical properties i.e. thickness, solubility, tensile strength, % elongation, and water vapor transmission rate (WVTR), as well as on the sensory characteristics of texture i.e. wateriness, firmness, elasticity, hardness, and juiciness of the coated products. The result shown that the higher the concentration the higher the thickness of EF, where as for myofibril proteins appeared higher than carrageenan and collagen. Both of collagen and myofibril shown that concentration of 6% was most soluble, while for carrageenan were in concentration of 2 to 2.5%. For tensile strength, carrageenan was significantly higher than myofibril and collagen; while for elongation, collagen film more elastic than carragenan and myofibril protein. Water vapor transmission rate, shown that myofibril protein film lower than carrageenan and collagen film. From sensory assessment of texture, carrageenan has a high elasticity and juiciness, while collagen and myofibril have a high in firmness and hardness.

Keywords: edible film, collagen, myofibril, carrageenan

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Authors: Owonikoko A. D., Odoje O. F.

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Fresh sample of Eryngium alpinum was purchased and processed for leaf protein concentrates with a view to evaluating its nutritional potential, mineral composition, amino acid characteristics and phytochemical constituents. Using standard analytical methods. The proximate composition of the leaf protein concentrates revealed moisture content;(5.35±0.21)g/100g, ash;(11.37±0.43)g/100g, crude protein;(48.17±0.46)g/100g, crude fat;(15.38±0.07)g/100g, crude fibre (3.05±0.46)g/100g, and Nitrogen free extractive; (16.68±0.30) g/100g. The mineral content was: Na;(51.88±0.23) mg/100g, K;(65.40±0.32)mg/100g, Ca; (86.89±0.46)mg/100g, Mg;(49.27±0.42) mg/100g, Zn;(0.62±0.03)mg/100g, Fe (6.65±0.43)mg/100g, Mn;(0.96±0.54)mg/100g, Cd;(0.28±0.04)mg/100g, P; (8.55±0.97)mg/100g, while selenium, lead and mercury were not detected in the sample indicating that the sample is free of causing risk of metal poisoning. The results of phytochemical constituents showed phytate; (18.34±0.36)mg/100g, flavonoid (0.25±0.41)mg/100g. The sample contain both essential and non-essential amino acid, with the highest value of Glutamic acid (12.26) and the lowest value of Tryptophan 1.05. the content of the leaf protein content shows that the sample is fit for dietary consumption and could as well be processed to be used as food additives.

Keywords: mineral composition, phytochemical analysis, leaf protein concentrates, eryngium alpinum

Procedia PDF Downloads 109

Authors: Saif Alomari

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The paper aims at giving physical and mathematical descriptions of how the structural parameters of a resonant tunnelling diode (RTD) affect its output characteristics. Specifically, the value of the peak voltage, peak current, peak to valley current ratio (PVCR), and the difference between peak and valley voltages and currents ΔV and ΔI. A simulation-based approach using the Non-Equilibrium Green Function (NEGF) formalism based on the Silvaco ATLAS simulator is employed to conduct a series of designed experiments. These experiments show how the doping concentration in the emitter and collector layers, their thicknesses, and the width of the barriers and the quantum well influence the above-mentioned output characteristics. Each of these parameters was systematically changed while holding others fixed in each set of experiments. Factorial experiments are outside the scope of this work and will be investigated in future. The physics involved in the operation of the device is thoroughly explained and mathematical models based on curve fitting and underlaying physical principles are deduced. The models can be used to design devices with predictable output characteristics. These models were found absent in the literature that the author acanned. Results show that the doping concentration in each region has an effect on the value of the peak voltage. It is found that increasing the carrier concentration in the collector region shifts the peak to lower values, whereas increasing it in the emitter shifts the peak to higher values. In the collector’s case, the shift is either controlled by the built-in potential resulting from the concentration gradient or the conductivity enhancement in the collector. The shift to higher voltages is found to be also related to the location of the Fermi-level. The thicknesses of these layers play a role in the location of the peak as well. It was found that increasing the thickness of each region shifts the peak to higher values until a specific characteristic length, afterwards the peak becomes independent of the thickness. Finally, it is shown that the thickness of the barriers can be optimized for a particular well width to produce the highest PVCR or the highest ΔV and ΔI. The location of the peak voltage is important in optoelectronic applications of RTDs where the operating point of the device is usually the peak voltage point. Furthermore, the PVCR, ΔV, and ΔI are of great importance for building RTD-based oscillators as they affect the frequency response and output power of the oscillator.

Keywords: peak to valley ratio, peak voltage shift, resonant tunneling diodes, structural parameters

Procedia PDF Downloads 142

Authors: Wen-Hsiang Lai, Mei-Wen Chen

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In the face of developing new technologies, identifying potential new technological product and the suitable market is important. Since laser technology is widely applied in many industries, this study explores the technology commercialization of laser technology. According to the literature review and industry analysis, this study discusses the factors influencing the consumer’s purchase intention and tries to find a new market direction to develop the laser technology. This study adopts a new product adoption model as the research framework and uses three variables of ‘Consumer characteristics’, ‘Perception of product attributes’ and ‘External environment’ to discuss the purchase intention of consumers, who are physicians and owners of the medical cosmetics. This study finds that in the major variable of ‘Consumer characteristics’, the sub-variables of ‘Personality’, ‘Knowledge of product’, ‘Perceived risk’ and ‘Motivation’ are significantly related to consumer’s purchase intention. In the major variable of ‘Perception of product attributes’, the sub-variables of ‘Brand’ and ‘Measure of manufacture country’ are the key factors that affect the willingness of consumer’s purchase intention. Finally, in the major variable of ‘External environment’ variable, the sub-variables of ‘Time’ and ‘Price’ have significant impact on consumer’s purchase intention.

Keywords: technology commercialization, new product adoption, consumer’s purchase intention, laser technology

Procedia PDF Downloads 195

Authors: Boualem Chetti, Samir Zahaf

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This paper presents the steady-state performance analysis of a four-lobe journal bearing lubricated with a couple stress fluids operating in the turbulent regime, following Constantinescu’s turbulent lubrication theory. The modified Reynolds equation is solved numerically using the finite difference method taking into consideration the effects of the turbulence and the couple stress. In this analysis, the steady-state parameters in terms of the attitude angle, load carrying capacity, side leakage and friction coefficient are determined at various values of eccentricities ratio. The computed results show that the turbulence increases the load carrying capacity, the attitude angle and the friction coefficient for a journal bearing lubricated with a Newtonian or a couple stress fluids. It is found that the turbulence has strongly influence on the steady-state performances of the four-lobe journal bearing lubricated with Newtonian fluids or a couple stress fluids.

Keywords: Four-lobe journal bearings, static characteristics, couple-stress fluids, turbulent flow

Procedia PDF Downloads 193

Authors: Poojan Kothari, Yash Madhani, Chayan Jani, Bharti Saini

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The requirements for quality drinking and industrial water are increasing and water resources are depleting. Moreover large amount of wastewater is being generated and dumped into water bodies without treatment. These have made improvement in water treatment efficiency and its reuse, an important agenda. Membrane technology for wastewater treatment is an advanced process and has become increasingly popular in past few decades. There are many traditional methods for tertiary treatment such as chemical coagulation, adsorption, etc. However recent developments in membrane technology field have led to manufacturing of better quality membranes at reduced costs. This along with the high costs of conventional treatment processes, high separation efficiency and relative simplicity of the membrane treatment process has made it an economically viable option for municipal and industrial purposes. Ultrafiltration polymeric membranes can be used for wastewater treatment and drinking water applications. The proposed work focuses on preparation of one such UF membrane - Polyvinylidene fluoride (PVDF) doped with LiBr for wastewater treatment. Majorly all polymeric membranes are hydrophobic in nature. This property leads to repulsion of water and hence solute particles occupy the pores, decreasing the lifetime of a membrane. Thus modification of membrane through addition of small amount of salt such as LiBr helped us attain certain characteristics of membrane, which can then be used for wastewater treatment. The membrane characteristics are investigated through measuring its various properties such as porosity, contact angle and wettability to find out the hydrophilic nature of the membrane and morphology (surface as well as structure). Pure water flux, solute rejection and permeability of membrane is determined by permeation experiments. A study of membrane characteristics with various concentration of LiBr helped us to compare its effectivity.

Keywords: Lithium bromide (LiBr), morphology, permeability, Polyvinylidene fluoride (PVDF), solute rejection, wastewater treatment

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Authors: Pawandeep Kaur, Prashant Garg

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Red mud is a byproduct of aluminum extraction from Bauxite industry. It is dumped in a pond which not only uses thousands of acres of land but having very high pH, it pollutes the ground water and the soil also. Leaves are yet another big waste especially during autumn when they contribute immensely to the blockage of drains and can easily catch fire, among other risks hence also needs to be utilized effectively. The use of leaf ash and red mud in highway construction as a filling material may be an efficient way to dispose of leaf ash and red mud. In this study, leaf ash and lime were used as admixtures to improve the geotechnical engineering properties of red mud. The red mud was taken from National Aluminum Company Limited, Odisha, and leaf ash was locally collected. The aim of present study is to investigate the effect of lime and leaf ash on compaction characteristics and strength characteristics of red mud. California Bearing Ratio and Unconfined Compression Strength tests were performed on red mud by varying different percentages of lime and leaf ash. Leaf ash was added in proportion 2%,4%,6%,8% and 10% whereas lime was added in proportions of 5% to 15%. Optimized value of lime was decided with respect to maximum CBR (California Bearing Ratio) of red mud mixed with different proportions of lime. An increase of 300% in California Bearing ratio of red mud and an increase of 125% in Unconfined Compression Strength values were observed. It may, therefore, be concluded that red mud may be effectively utilized in the highway industry as a filler material.

Keywords: stabilization, lime, red mud, leaf ash

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Authors: Peng Hao Wang, Ronald Sterkenburg, Garam Kim, Yuwei He

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As composite materials continue to gain popularity in the aerospace industry; large airframe sections made out of composite materials are becoming the standard for aerospace manufacturers. However, the heavy utilization of these composite materials also increases the importance of the recycling of these composite materials. A team of Purdue University School of Aviation and Transportation Technology (SATT) faculty and students have partnered to investigate the characteristics of 3D printed recycled carbon fiber. A prototype of a 3D printed recycled carbon fiber part was provided by an industry partner and different sections of the prototype were used to create specimens. A furnace was utilized in order to remove the polymer from the specimens and the specimen’s fiber content and fiber length was calculated from the remaining fibers. A differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) test was also conducted on the 3D printed recycled carbon fiber prototype in order to determine the prototype’s degree of cure at different locations. The data collected from this study provided valuable information in the process improvement and understanding of 3D printed recycled carbon fiber.

Keywords: 3D printed, carbon fiber, fiber content, recycling

Procedia PDF Downloads 190

Authors: N. Manoj

Abstract:

The aeroelastic behavior of engine nacelle strake when subjected to unsteady aerodynamic flows is investigated in this paper. Geometric nonlinear characteristics and modal parameters of nacelle strake are studied when it is under dynamic loading condition. Here, an N-S based Finite Volume solver is coupled with Finite Element (FE) based nonlinear structural solver to investigate the nonlinear characteristics of nacelle strake over a range of dynamic pressures at various phases of flight like takeoff, climb, and cruise conditions. The combination of high fidelity models for both aerodynamics and structural dynamics is used to predict the nonlinearities of strake (chine). The methodology adopted for present aeroelastic analysis is partitioned-based time domain coupled CFD and CSD solvers and it is validated by the consideration of experimental and numerical comparison of aeroelastic data for a cropped delta wing model which has a proven record. The present strake geometry is derived from theoretical formulation. The amplitude and frequency obtained from the coupled solver at various dynamic pressures is discussed, which gives a better understanding of its impact on aerodynamic design-sizing of strake.

Keywords: aeroelasticity, finite volume, geometric nonlinearity, limit cycle oscillations, strake

Procedia PDF Downloads 284

Authors: Kirti Singh, Kesheo Prasad

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A 3D Acoustic Doppler velocimeter was used in the current investigation to quantify the mean and turbulence characteristics in non-uniform open-channel flows. Results are obtained from studies done in the laboratory, analysing the behavior of sand particles under turbulent open channel flow conditions flowing through rough, porous beds. Data obtained from ADV is used to calculate turbulent flow characteristics, Reynolds stresses and turbulent kinetic energy. Theoretical formulations for the distribution of Reynolds stress and the vertical velocity have been constructed using the Reynolds equation and the continuity equation of 2D open-channel flow. The measured Reynolds stress profile and the vertical velocity are comparable with the derived expressions. This study uses the Navier-Stokes equations for analysing the behavior of the vertical velocity profile in the dominant region of full-fledged turbulent flows in open channels, and it gives a new origination of the profile. For both wide and narrow open channels, this origination can estimate the time-averaged primary velocity in the turbulent boundary layer's outer region.

Keywords: turbulence, bed roughness, logarithmic law, shear stress correlations, ADV, Reynolds shear stress

Procedia PDF Downloads 107

Authors: Mohsen Davarzani, Ehsan Lame, Mohammad Taghi Hassan Zadeh

Abstract:

Language is considered as a powerful and outstanding feature of ethnicity. However, humiliating and prohibiting using human language is one the most heinous and brutal acts in the form of racism. In other words, racism can be a product of physiological humiliations and discrimination, such as skin color, and can also be resulted from ethnic humiliation and discrimination such as language, customs and so on. Ethnic and racial discrimination is one of the main problems of the world that minorities and occasionally the majority have suffered from. Nowadays, few states can be found in which all individuals and its citizens are of the same race and ethnicity, culture and language. In these countries, referred to as the multinational states, (eg, Iran, Switzerland, India, etc.), there are the communities and groups which have their own linguistic, cultural and historical characteristics. Characteristics of human rights issues, diversity of issues and plurality of meanings indicate that they appear in various aspects. The states are obliged to respect, as per national and international obligations, the rights of all citizens from different angles, especially different groups that require special attention in order of the particular aspects such as ethnicity, religious and political minorities, children, women, workers, unions and in case the states are in breach of any of these items, they are faced with challenges in local, regional or international fields.

Keywords: law, language, minorities, ethnicity

Procedia PDF Downloads 418

Authors: Dong Wei, Wu Jinxiu

Abstract:

As China's urban construction enters a new phase of 'stock optimization,' the key point of urban development has shifted to the development and reuse of existing public space. However, cities still face a series of challenges, such as the shortage of space quantity and insufficient space quality, which indirectly affect urban vitality. A review of the vitality of urban public space will significantly contribute to optimizing the quality of the urban built environment. It firstly analyses the research hotspots of urban vitality at home and abroad, based on a semi-systematic literature review. Then this paper summarizes the theoretical definitions of the vitality of urban public space and sorts out the influencing factors from the perspectives of society, environment, and users. Lastly, the paper concludes with the mainstream quantitative and evaluation methods, such as linear evaluation and integrated evaluation. This paper renders a multi-theoretical perspective to understand the characteristics and evaluation system of the vitality of public space, which helps to acknowledge the dynamic relationship between users, urban environment, and vitality. It also looks forward to providing optimal design strategies for constructing a vigorous public space in future cities.

Keywords: public space, quantification of vitality, spatial vitality, urban vitality

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Authors: S. Shamohammadi, L. Razavi

Abstract:

This paper based on the principle concepts of SCS-CN model, a new mathematical model for computation of retention potential (S) presented. In the mathematical model, not only precipitation-runoff concepts in SCS-CN model are precisely represented in a mathematical form, but also new concepts, called “maximum retention” and “total retention” is introduced, and concepts of potential retention capacity, maximum retention, and total retention have been separated from each other. In the proposed model, actual retention (F), maximum actual retention (Fmax), total retention (S), maximum retention (Smax), and potential retention (Sp), for the first time clearly defined, so that Sp is not variable, but a function of morphological characteristics of the watershed. Indeed, based on the mathematical relation of the conceptual curve of SCS-CN model, the proposed model provides a new method for the computation of actual retention in watershed and it simply determined runoff based on. In the corresponding relations, in addition to Precipitation (P), Initial retention (Ia), cumulative values of actual retention capacity (F), total retention (S), runoff (Q), antecedent moisture (M), potential retention (Sp), total retention (S), we introduced Fmax and Fmin referring to maximum and minimum actual retention, respectively. As well as, ksh is a coefficient which depends on morphological characteristics of the watershed. Advantages of the modified version versus the original model include a better precision, higher performance, easier calibration and speed computing.

Keywords: model, mathematical, retention, watershed, SCS

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Authors: Ming Lu, Xiaojun Li, Bodi Lu, Juehui Xing

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Earthquake damage phenomenon of each large earthquake gives comprehensive and profound real test to the dynamic performance and failure mechanism of different engineering structures. Cognitive engineering structure characteristics through seismic damage phenomenon are often far superior to expensive shaking table experiments. After the earthquake, people will record a variety of different types of engineering damage photos. However, a large number of earthquake damage photographs lack sufficient information and reduce their using value. To improve the research value and the use efficiency of engineering seismic damage photographs, this paper objects to explore and show seismic damage background information, which includes the earthquake magnitude, earthquake intensity, and the damaged structure characteristics. From the research requirement in earthquake engineering field, the authors use the 2008 China Wenchuan M8.0 earthquake photographs, and provide four kinds of attribute indexes and classification, which are seismic information, structure types, earthquake damage parts and disaster causation factors. The final object is to set up an engineering structural seismic damage database based on these four attribute indicators and classification, and eventually build a website providing seismic damage photographs.

Keywords: attribute index, classification method, earthquake damage picture, engineering structure

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Authors: Hammadi Larbi

Abstract:

The treatment of wastewater in sewage plants usually results in the formation of a large amount of sludge. These appear at the outlet of the treatment plant as a viscous fluid loaded with a high concentration of dry matter. This sludge production presents environmental, ecological, and economic risks. That is why it is necessary to find many solutions for minimizing these risks. In the present article, the effect of hydrogen peroxide, thermal treatment, and quicklime on the characteristics of the activated sludge produced in urban wastewater plant were evaluated in order to avoid any risk in the plants. The study shows increasing of the dose of H2O2 from 0 to 0.4 g causes an increase in the solubilization rate of COD from 12% to 45% and a reduction in the organic matter content of sludge (VM/SM) from 74% to 36% . The results also show that the optimum efficiency of the heat treatment corresponds to a temperature of 80 ° C for a treatment time of 40 min is 47% and 51.82% for a temperature equal to 100 ° C and 76.30 % for a temperature of 120 ° C, and 79.38% for a temperature of 140 ° C. The treatment of sludge by quicklime gives the optimum efficiency of 70.62 %. It was shown the increasing of the temperature from 80°C to 140°C, the pH of sludge was increased from 7.12 to 9.59. The obtained results showed that with increasing the dose of quicklime from 0 g/l to 1g/l in activated sludge led to an increase of their pH from 7.12 to 12.06. The study shows the increasing the dose of quicklime from 0 g/l to 1g/l causes also an increase in the solubilization of COD from 0% to 70.62 %

Keywords: activated sludge, hydrogen peroxide, thermal treatment, quicklime

Procedia PDF Downloads 104

Authors: Vladimir V. Nikulin, Bekmurza H. Aitchanov, Olimzhon A. Baimuratov

Abstract:

Quantum communication technology takes advantage of the intrinsic properties of laser carriers, such as very high data rates and low power requirements, to offer unprecedented data security. Quantum processes at the physical layer of encryption are used for signal encryption with very competitive performance characteristics. The ultimate range of applications for QC systems spans from fiber-based to free-space links and from secure banking operations to mobile airborne and space-borne networking where they are subjected to channel distortions. Under practical conditions, the channel can alter the optical wave front characteristics, including its phase. In addition, phase noise of the communication source and photo-detection noises alter the signal to bring additional ambiguity into the measurement process. If quantized values of photons are used to encrypt the signal, exploitation of quantum communication links becomes extremely difficult. In this paper, we present the results of analysis and simulation studies of the effects of noise on phase estimation for quantum systems with different number of encryption bases and operating at different power levels.

Keywords: encryption, phase distortion, quantum communication, quantum noise

Procedia PDF Downloads 553

Authors: G. Peker, Tolga N. Aynur, E. Tinar

Abstract:

In order to determine the energy consumption level and cooling characteristics of a domestic refrigerator controlled with various cooling system algorithms, a side by side type (SBS) refrigerator was tested in temperature and humidity controlled chamber conditions. Two different control algorithms; so-called drop-in and frequency controlled variable capacity compressor algorithms, were tested on the same refrigerator. Refrigerator cooling characteristics were investigated for both cases and results were compared with each other. The most important comparison parameters between the two algorithms were taken as; temperature distribution, energy consumption, evaporation and condensation temperatures, and refrigerator run times. Standard energy consumption tests were carried out on the same appliance and resulted in almost the same energy consumption levels, with a difference of %1,5. By using these two different control algorithms, the power consumptions character/profile of the refrigerator was found to be similar. By following the associated energy measurement standard, the temperature values of the test packages were measured to be slightly higher for the frequency controlled algorithm compared to the drop-in algorithm. This paper contains the details of this experimental study conducted with different cooling control algorithms and compares the findings based on the same standard conditions.

Keywords: control algorithm, cooling, energy consumption, refrigerator

Procedia PDF Downloads 373