Search results for: constriction

Authors: S. S. Dol, M. S. Chan, S. F. Wong, J. S. Lim

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Emulsion formation is unavoidable and can be detrimental to an oil field production. The presence of stable emulsions also reduces the quality of crude oil and causes more problems in the downstream refinery operations, such as corrosion and pipeline pressure drop. Hence, it is important to know the effects of emulsions in the pipeline. Light crude oil was used for the continuous phase in the W/O emulsions where the emulsions pass through a flow loop to test the pressure drop across the pipeline. The results obtained shows that pressure drop increases as water cut is increased until it peaks at the phase inversion of the W/O emulsion between 30% to 40% water cut. Emulsions produced by gradual constrictions show a lower stability as compared to sudden constrictions. Lower stability of emulsions in gradual constriction has the higher influence of pressure drop compared to a sudden sharp decrease in diameter in sudden constriction. Generally, sudden constriction experiences pressure drop of 0.013% to 0.067% higher than gradual constriction of the same ratio. Lower constriction ratio cases cause larger pressure drop ranging from 0.061% to 0.241%. Considering the higher profitability in lower emulsion stability and lower pressure drop at the developed flow region of different constrictions, an optimum design of constriction is found to be gradual constriction with a ratio of 0.5.

Keywords: constriction, pressure drop, turbulence, water-in-oil emulsions

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Authors: Himanshu Shekhar Maharana, S. K .Dash

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Economic Load Dispatch (ELD) proves to be a vital optimization process in electric power system for allocating generation amongst various units to compute the cost of generation, the cost of emission involving global warming gases like sulphur dioxide, nitrous oxide and carbon monoxide etc. In this dissertation, we emphasize ramp rate constriction factor based particle swarm optimization (RRCPSO) for analyzing various performance objectives, namely cost of generation, cost of emission, and a dual objective function involving both these objectives through the experimental simulated results. A 6-unit 30 bus IEEE test case system has been utilized for simulating the results involving improved weight factor advanced ramp rate limit constraints for optimizing total cost of generation and emission. This method increases the tendency of particles to venture into the solution space to ameliorate their convergence rates. Earlier works through dispersed PSO (DPSO) and constriction factor based PSO (CPSO) give rise to comparatively higher computational time and less good optimal solution at par with current dissertation. This paper deals with ramp rate and constriction factor based well defined ramp rate PSO to compute various objectives namely cost, emission and total objective etc. and compares the result with DPSO and weight improved PSO (WIPSO) techniques illustrating lesser computational time and better optimal solution. 

Keywords: economic load dispatch (ELD), constriction factor based particle swarm optimization (CPSO), dispersed particle swarm optimization (DPSO), weight improved particle swarm optimization (WIPSO), ramp rate and constriction factor based particle swarm optimization (RRCPSO)

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Authors: Nishanthi N. S., Srikanth Vedantam

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Intracellular delivery of materials has always proved to be a challenge in research and therapeutic applications. Usually, vector-based methods, such as liposomes and polymeric materials, and physical methods, such as electroporation and sonoporation have been used for introducing nucleic acids or proteins. Reliance on exogenous materials, toxicity, off-target effects was the short-comings of these methods. Microinjection was an alternative process which addressed the above drawbacks. However, its low throughput had hindered its adoption widely. Mechanical deformation of cells by squeezing them through constriction channel can cause the temporary development of pores that would facilitate non-targeted diffusion of materials. Advantages of this method include high efficiency in intracellular delivery, a wide choice of materials, improved viability and high throughput. This cell squeezing process can be studied deeper by employing simple models and efficient computational procedures. In our current work, we present a finite sized dissipative particle dynamics (FDPD) model to simulate the dynamics of the cell flowing through a constricted channel. The cell is modeled as a capsule with FDPD particles connected through a spring network to represent the membrane. The total energy of the capsule is associated with linear and radial springs in addition to constraint of the fixed area. By performing detailed simulations, we studied the strain on the membrane of the capsule for channels with varying constriction heights. The strain on the capsule membrane was found to be similar though the constriction heights vary. When strain on the membrane was correlated to the development of pores, we found higher porosity in capsule flowing in wider channel. This is due to localization of strain to a smaller region in the narrow constriction channel. But the residence time of the capsule increased as the channel constriction narrowed indicating that strain for an increased time will cause less cell viability.

Keywords: capsule, cell squeezing, dissipative particle dynamics, intracellular delivery, microfluidics, numerical simulations

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Authors: Ashkan Javadzadegan, Aitak Javadzadegan, Babak Fakhim

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One of possible ways to retard movement of fluid is through applying an external magnetic field. In this regard, this study is focused on the effect of a uniform transverse magnetic field on fluid flow behavior inside a channel with a local symmetric constriction. Also, Ellis Non-Newtonian model is implemented to address the effects of shear-dependent viscosity. According to the results, the flow separation downstream of the constriction can be controlled by applying an external magnetic field and/or manipulating the shear-thinning degree of fluid. It is also demonstrated that pressure drop increases by an increase in the strength of the magnetic field.

Keywords: magnetic field, non-Newtonian, separation, shear thinning

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Authors: S. Atabay, T. A. Ali, Md. M. Mortula

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This paper presents the results and findings from a parametric study on the water surface elevation at upstream of bridge constriction for subcritical flow. In this study, the influence of Manning's Roughness Coefficient of main channel (nmc) and of floodplain (nfp), and bridge opening (b) flow rate (Q), contraction (kcon), and expansion coefficients (kexp) were investigated on backwater level. The DECK bridge models with different span widths and without any pier were investigated within the two stage channel having various roughness conditions. One of the most commonly used commercial one-dimensional HEC-RAS model was used in this parametric study. This study showed that the effects of main channel roughness (nmc) and flow rate (Q) on the backwater level are much higher than those of the floodplain roughness (nfp). Bridge opening (b) with contraction (kcon) and expansion coefficients (kexp) have very little effect on the backwater level within this range of parameters.

Keywords: bridge backwater, parametric study, waterways, HEC-RAS model

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Authors: Omid Ataei Nia, Karim Salahshoor

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In this paper, a new precise and reliable sensor network methodology is introduced for unit processes and operations using the Constriction Coefficient Particle Swarm Optimization (CPSO) method. CPSO is introduced as a new search engine for optimal sensor network design purposes. Furthermore, a Square Root Unscented Kalman Filter (SRUKF) algorithm is employed as a new data reconciliation technique to enhance the stability and accuracy of the filter. The proposed design procedure incorporates precision, cost, observability, reliability together with importance-of-variables (IVs) as a novel measure in Instrumentation Criteria (IC). To the best of our knowledge, no comprehensive approach has yet been proposed in the literature to take into account the importance of variables in the sensor network design procedure. In this paper, specific weight is assigned to each sensor, measuring a process variable in the sensor network to indicate the importance of that variable over the others to cater to the ultimate sensor network application requirements. A set of distinct scenarios has been conducted to evaluate the performance of the proposed methodology in a simulated Continuous Stirred Tank Reactor (CSTR) as a highly nonlinear process plant benchmark. The obtained results reveal the efficacy of the proposed method, leading to significant improvement in accuracy with respect to other alternative sensor network design approaches and securing the definite allocation of sensors to the most important process variables in sensor network design as a novel achievement.

Keywords: constriction coefficient PSO, importance of variable, MRMSE, reliability, sensor network design, square root unscented Kalman filter

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Authors: Mangala M. Pai, B. V. Murlimanju, Latha V. Prabhu, P. J. Jiji , Vandana Blossom

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Background:To study the morphological parameters of the axis vertebra in anatomical specimens. Methods: The present study was designed to obtain the morphometric data of axis vertebra. The superior and inferior articular facets of the axis were macroscopically observed for their shapes and the different parameters were measured using the digital Vernier caliper. It included 20 dried axis bones, which were obtained from the anatomy laboratory. Results: The morphometric data obtained in the present study are represented in the tables. The side wise comparison of the length and width of the articular facets of the axis vertebra were done. The present study observed that, there is no statistically significant difference observed among the parameters of right and left side articular facets (p>0.05). The superior and inferior articular facets were observed to have variable shapes. The frequencies of different shapes of superior and inferior articular facets are represented in figures. All the shapes of the inferior and superior articular facets were symmetrical over the right and left sides. Among the superior articular facets, the constrictions were absent in 13 cases (65%), 2 (10%) exhibited a single constriction, 3 (15%) had 2 constrictions and 2 (10%) were having 3 constrictions. The constrictions were absent in 11 (55%) of the inferior articular facets, 3 (15%) of them had 1 constriction, 3 (15%) were having 2 constrictions, 2 (10%) exhibited 3 constrictions and 1 (5%) of them had 4 constrictions. The constrictions of the inferior and superior articular facets were symmetrical over the right and left sides. Conclusion: We believe that the present study has provided additional information on the morphometric data of the axis vertebra. The data are important to the neurosurgeons, orthopedic surgeons and radiologists. The preoperative assessment of the axis vertebra may prevent dangerous complications like spinal cord and nerve root compression during the surgical intervention.

Keywords: axis, articular facet, morphology, morphometry

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Authors: Christina Hagen, Pragathi Kamale Gurmurthy, Thorsten M. Buzug

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CFD simulations are performed in the upper airway of a patient suffering from obstructive sleep apnea (OSA) that is a sleep related breathing disorder characterized by repetitive partial or complete closures of the upper airways. The simulations are aimed at getting a better understanding of the pathophysiological flow patterns in an OSA patient. The simulation is compared to medical data of a sleep endoscopic examination under sedation. A digital model consisting of surface triangles of the upper airway is extracted from the MR images by a region growing segmentation process and is followed by a careful manual refinement. The computational domain includes the nasal cavity with the nostrils as the inlet areas and the pharyngeal volume with an outlet underneath the larynx. At the nostrils a flat inflow velocity profile is prescribed by choosing the velocity such that a volume flow rate of 150 ml/s is reached. Behind the larynx at the outlet a pressure of -10 Pa is prescribed. The stationary incompressible Navier-Stokes equations are numerically solved using finite elements. A grid convergence study has been performed. The results show an amplification of the maximal velocity of about 2.5 times the inlet velocity at a constriction of the pharyngeal volume in the area of the tongue. It is the same region that also shows the highest pressure drop from about 5 Pa. This is in agreement with the sleep endoscopic examinations of the same patient under sedation showing complete contractions in the area of the tongue. CFD simulations can become a useful tool in the diagnosis and therapy of obstructive sleep apnea by giving insight into the patient’s individual fluid dynamical situation in the upper airways giving a better understanding of the disease where experimental measurements are not feasible. Within this study, it could been shown on one hand that constriction areas within the upper airway lead to a significant pressure drop and on the other hand a good agreement of the area of pressure drop and the area of contraction could be shown.

Keywords: biomedical engineering, obstructive sleep apnea, pharynx, upper airways

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Authors: Ryan Masoodi, Hossein Rostami

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Aluminum has been credited for the massive advancement of many industrial products, from aerospace and automotive to electronics and even household appliances. These developments have come with a cost, which is a toxic by-product. The rise of aluminum production has been accompanied by the rise of a waste material called Bauxite Residue or Red Mud. This toxic material has been proved to be harmful to the environment, yet, there is no proper way to dispose or recycle it. Herewith, a new experimental method to utilize this waste in the building material is proposed. A method to mix red mud, fly ash, and some other ingredients is explored to create a new construction material that can satisfy the minimum required strength for bricks. It concludes that it is possible to produce bricks with enough strength that is suitable for constriction in environments with low to moderate weather conditions.

Keywords: bauxite residue, brick, red mud, recycling

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Authors: Fuzhang Zhao

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Particle swarm optimization (PSO) is becoming one of the most important swarm intelligent paradigms for solving global optimization problems. Although some progress has been made to improve PSO algorithms over the last two decades, additional work is still needed to balance parameters to achieve better numerical properties of accuracy, efficiency, and stability. In the optimal PSO algorithm, the optimal weightings of (√ 5 − 1)/2 and (3 − √5)/2 are used for the cognitive factor and the social factor, respectively. By the same token, the same optimal weightings have been applied for intensification searches and diversification searches, respectively. Perturbation and constriction effects are optimally balanced. Simulations of the de Jong, the Rosenbrock, and the Griewank functions show that the optimal PSO algorithm indeed achieves better numerical properties and outperforms the canonical PSO algorithm.

Keywords: diversification search, intensification search, optimal weighting, particle swarm optimization

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Authors: Krista Mae F. Ramos, Lance Micaiah C. Dauz, Gylza Nicole D. Bautista, Rua R. Galang, Jeric Xyrus G. Karganilla

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With the recent proclamation of the possible reinforcement of Compulsory Military Service in the Philippines, debates and societal talks rose and circulated as opinions and perceptions regarding the topic continue to clash. This study aims to determine the perception of the youth on its reimplementation and identify various advantages and disadvantages based on their perspective. The responses were gathered through a virtual call interview, underwent the process of thematization, and were categorized into different themes. Results reflect that the students perceive compulsory military service as a necessity for national defense but requires a long time that can hinder their education and needs a strong foundation to be implemented and sustained. The participants acknowledged that the practice would instill discipline, patriotism, and nationalism, develop an individual’s physical abilities, provide skills and knowledge and improve a person’s self-defense. However, there are also concerns regarding the prominent military shaping and abuse, their loss of freedom of choice, and the chances of health deterioration.

Keywords: compulsory, military, service, reinforcement, perception

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Authors: Eric Chappel, Dimitry Dumont-Fillon, Hugo Musard, Harald van Lintel

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A microfluidic radial diffuser typically comprises a hole in a membrane, a small gap and pillar centred with the hole. The fluid is forced to flow radially in this gap between the membrane and the pillar. Such diffusers are notably used to form flow control valves, wherein several holes are machined into a flexible membrane progressively deflecting against pillars as the pressure increases. The fluidic modelling of such diffuser is made difficult by the presence of a transition region between the hole and the diffuser itself. An experimental investigation has been conducted using SOI wafers to form membranes with only one centred hole and Pyrex wafers for the substrate and pillars, both wafers being anodically bonded after alignment. A simple fluidic model accounting for the specific geometry of the diffuser is proposed and compared to experimental results. A good match is obtained, for Reynolds number in the range 0.5 to 35 using the analytical formula of a radial diffuser in the laminar regime with an effective inner radius that is 40% smaller than the real radius, in order to simulate correctly the flow constriction at the entrance of the diffuser.

Keywords: radial diffuser, flow control valve, numerical modelling, drug delivery

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Authors: Erfan Ghasemi, Mohammadreza Khani, Hamidreza Mahmoudi, Mohammad Ali Nilforoushzadeh, Babak Shokri, Pouria Akbartehrani

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Given the global significance of treating infectious wounds, the goal of this study is to use spark plasma as a new treatment for infectious wounds. To generate spark plasma, a high-voltage (7 kV) and high-frequency (75 kHz) source was used. Infectious wounds in the peritoneum of mice were divided into control and plasma-treated groups at random. The plasma-treated animals received plasma radiation every 4 days for 12 days, for 60 seconds each time. On the 15th day after the first session, the wound in the plasma-treated group had completely healed. The spectra of spark plasma emission and tissue properties were studied. The mechanical resistance of the wound healed in the plasma treatment group was considerably higher than in the control group (p<0.05), according to the findings. Furthermore, histological evidence suggests that wound re-epithelialization is faster in comparison to controls. Angiogenesis and fibrosis (collagen production) were also dramatically boosted in the plasma-treated group, whereas the stage of wound healing inflammation was significantly reduced. Plasma therapy accelerated wound healing by causing considerable wound constriction. The results of this investigation show that spark plasma has an influence on the treatment of infectious wounds.

Keywords: infectious wounds, mice, spark plasma, treatment

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Authors: Ezzati Givi M., Ezzatigivi N., Eimani H.

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Trigeminal Neuralgia (TN) consists of painful attacks often triggered with general activities, which cause impairment and disability. The first line of treatment consists of pharmacotherapy. However, the occurrence of many side-effects limits its application. Acute pain relief is crucial for titrating oral drugs and making time for neurosurgical intervention. This study aimed to examine the long-term anesthetic effect of QX-314 and capsaicin in trigeminal neuralgia using an animal model. TN was stimulated by surgical constriction of the infraorbital nerve in rats. After seven days, anesthesia infiltration was done, and the duration of mechanical allodynia was compared. Thirty-five male Wistar rats were randomly divided into seven groups as follows: control (normal saline); lidocaine (2%); QX314 (30 mM); lidocaine (2%)+QX314 (15 mM); lidocaine (2%)+QX314 (22 mM); lidocaine (2%)+QX314 (30 mM); and lidocaine (2%)+QX314 (30 mM) +capsaicin (1μg). QX314 in combination with lidocaine significantly increased the duration of anesthesia, which was dose-dependent. The combination of lidocaine+QX314+capsaicin could significantly increase the duration of anesthesia in trigeminal neuralgia. In the present study, we demonstrated that the combination of QX-314 with lidocaine and capsaicin produced a long-lasting, reversible local anesthesia and was superior to lidocaine alone in the fields of the duration of trigeminal neuropathic pain blockage.

Keywords: trigeminal neuralgia, capsaicin, lidocaine, long-lasting

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Authors: Abdul M. Khan, Hafiza I. Naz, Ayesha Iqbal, Muhammad Akhtar

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The fossil remains described in this study have been recovered during fieldwork by the authors from the Dhok Pathan Formation of Middle Siwaliks Pakistan in December, 2015. The sample comprises maxillary and mandibular fragments along with isolated upper and lower teeth. The morphometric analysis of the specimens led us to recognize the sample as belonging to Eotragus noyei, which has been considered as the smallest and the oldest bovid in the Siwaliks. Eotragus noyei is characterized by brachydont teeth, finely rugose enamel, more inclined buccal walls of the molars and small lingual cingula. The inclination of the metaconal area has caused rotation of the metastyle in relation to the antero-posterior tooth axis and thus situated more lingually. The protocone in second upper premolar is well developed and situated posteriorly and also has an anterior lingual constriction. The metaconule in the third upper molar is smaller than the protocone. The dentition in Eotragus noyei is smaller in size as compared to Eotragus sansaniensis and Eotragus lampangensis. In Eotragus noyei the buccal walls in molars are more inclined while in Eotragus sansaniensis they are less inclined. The genus Eotragus has been reported previously in the Lower and Middle Siwaliks of Pakistan; however, the recognition of the present sample as Eotragus noyei has extended the range of this species from Lower to the Middle Siwaliks of Pakistan.

Keywords: Boselaphini, Chakwal, Dhok Pathan, late miocene

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Authors: Luma Al-Tamimi, Hassan Farhat, Wessam Hasan

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A three-dimensional (3D) hybrid quasi-steady thermal lattice Boltzmann model is developed to couple the effects of surfactant, temperature, interfacial tension, and contact angle. This 3D model is an extended scheme of a previously introduced two-dimensional (2D) hybrid lattice Boltzmann model. The 3D model is used to study the combined multi-physics effects on emulsion systems flowing in rectangular microchannels with and without confinements, where the suspended phase is made of droplets, plugs, or a mixture of both. The simulation results show that emulsion systems with plugs as the suspended phase are more efficient than with droplets, whereas mixed systems that form large plugs through coalescence have even greater efficiency. The 3D contact angle model generates matching results to those of the 2D model, which were validated with experiments. Furthermore, the effects of various confinements on adhering single drop systems are investigated for delineating their influence on the power required for transporting the suspended phase through the channel. It is shown that the deeper the constriction is, the lower the system efficiency. Increasing the surfactant concentration or fluid temperature in a channel with confinement carries a substantial positive effect on oil droplet transportation.

Keywords: lattice Boltzmann method, thermal, contact angle, surfactants, high viscosity ratio, porous media

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Authors: Susanta Kumar Gachhayat, S. K. Dash

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Multi objective non-convex economic dispatch problems of a thermal power plant are of grave concern for deciding the cost of generation and reduction of emission level for diminishing the global warming level for improving green-house effect. This paper deals with ramp rate constraints for achieving better inequality constraints so as to incorporate valve point loading for cost of generation in thermal power plant through ramp rate biogeography based optimization involving mutation and migration. Through 50 out of 100 trials, the cost function and emission objective function were found to have outperformed other classical methods such as lambda iteration method, quadratic programming method and many heuristic methods like particle swarm optimization method, weight improved particle swarm optimization method, constriction factor based particle swarm optimization method, moderate random particle swarm optimization method etc. Ramp rate biogeography based optimization applications prove quite advantageous in solving non convex multi objective economic dispatch problems subjected to nonlinear loads that pollute the source giving rise to third harmonic distortions and other such disturbances.

Keywords: economic load dispatch, ELD, biogeography-based optimization, BBO, ramp rate biogeography-based optimization, RRBBO, valve-point loading, VPL

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Authors: Disha Batra

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With the advent of economic reforms in India in 1992, economic journalism in India has undergone a sea change along with the rise in the Indian economy. Squeezing out of economic news stories (economy-in-general) over business (individual corporate stories) and financial (financial and equity markets) news stories have been done and are still underway. The objective of the study is to explore how economic journalism – news stories about macroeconomic issues or economy-in-general has changed over the past three decades with the emergence of LPG (Liberalisation, Privatisation, and Globalisation) policies in India. The purpose of the study is to examine to what extent business and financial news are constricting economic news which is done by analysing news stories and content of business papers. The study is based on the content analyses of the top three Indian business dailies as per IRS (Indian Readership Survey) 2017. The parametric analysis of the different parameters (source of information, sub-topic, a dominant source in economic news, layout and framing, etc.) has been done in order to come across with the distinct adaptations and modifications by these dailies. The paper significantly dwells upon the thematic analysis of these newspapers in order to explore and find out the coverage given to various sub-themes of EBF (economic, business, and financial) journalism. The study revealed that stories concerning broader issues about the economy which are likely to be of public concern had been dropped. The paper further indicates an upward trend for the stories concerning individual corporate, equity, and financial markets. Findings of the study raise concern over the indicated disparity between economic and business news stories which may further limit the information that people need in order to make well-versed decisions.

Keywords: business-papers, business news, economic news, financial news

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Authors: Neha Narayanan

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The paper tries to explore the role of language in determining spaces occupied by women in everyday lives. It is inspired from an ongoing action research work which employs ‘immersion’- arriving at a research problematic through community research, as a methodology in a Kondh adivasi village, Kirkalpadu located in Rayagada district of the Indian state of Odisha. In the dominant development discourse, language is associated with either preservation or conservation of endangered language or empowerment through language. Beyond these, is the discourse of language as a structure, with the hegemonic quality to organise lifeworld in a specific manner. This rigid structure leads to an experience of constriction of space for women. In Kirkalpadu, the action research work is with young and unmarried women of the age 15-25. During daytime, these women are either in the agricultural field or in the bari -the backyard of the house whose rooms are linearly arranged one after the other ending with the kitchen followed by an open space called bari (in Odia) which is an intimate and gendered space- where they are not easily visible. They justify the experience of restriction in mobility and fear of moving out of the village alone by the argument that the place and the men are nihi-aaeh (not good). These women, who have dropped out of school early to contribute to the (surplus) labour requirement in the household, want to learn English to be able to read signboards when they are on the road, to be able to fill forms at a bank and use mobile phones to communicate with their romantic partner(s). But the incapacity to have within one’s grasp the province of language and the incapacity to take the mobile phone to the kind of requirements marked by the above mentioned impossible transactions with space restricts them to the bari of the house. The paper concludes by seeking to explore the possibilities of learning and rethinking languages which takes into cognizance the gendered experience of women and the desire of women to cross the borders and occupy spaces restricted to them.

Keywords: action research, gendered experience, language, space

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Authors: Richa Shri, Varinder Singh, Kundan Singh Bora, Abhishek Bhanot, Rahul Kumar, Amit Kumar, Ravinder Kaur

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The term ‘neuroprotection’ means preserving/salvaging function and structure of neurons. Neuroprotection is an adjunctive treatment option for neurodegenerative disorders. Oxidative stress is considered a major culprit in neurodegenerative disorders; hence, management strategies include use of antioxidants. Our search for a neuroprotective agent began with Allium cepa L. or onions, (family Amaryllidaceae) - a potent antioxidant. We have investigated the neuroprotective potential of onions in experimental models of ischemic stroke, diabetic neuropathy, neuropathic pain, and dementia. In pre and post-ischemic stroke model, the methanol extract of outer scales of onion bulbs (MEOS) prevented memory loss and motor in-coordination; reduced oxidative stress and cerebral infarct size. This also prevented and ameliorated diabetic neuropathy in mice. The MEOS was fractionated to yield a flavonoid rich fraction (FRF) that successfully reversed ischemia-reperfusion induced neuronal damage, thereby demonstrating that the flavonoids are responsible for the activity. The FRF effectively ameliorated chronic constriction induced neuropathic pain in rats. The FRF was subjected to bioactivity-guided fractionated. It was seen that FRF is more effective as compared to the isolated components probably due to synergism among the constituents (i.e., quercetin and quercetin glucosides) in the FRF. The outer scales of onion bulbs have great potential for prevention as well as for treatment of neuronal disorders. Red onions, with higher amounts of flavonoids as compared to the white onions, produced more significant neuroprotection. Thus, the standardized FRF from the waste material of a commonly used vegetable, especially the red variety, may be developed as a valuable neuroprotective agent.

Keywords: Allium cepa, antioxidant activity, flavonoid rich fraction, neuroprotection

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Authors: Chen Chuanzhi, Guo Yunyun

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The large linear array feeding parabolic cylindrical antenna of the satellite has the ability of large-area line focusing, multi-directional beam clusters simultaneously in a certain azimuth plane and elevation plane, corresponding quickly to different orientations and different directions in a wide frequency range, dual aiming of frequency and direction, and combining space power. Therefore, the large-diameter parabolic cylindrical antenna has become one of the new development directions of spaceborne antennas. Limited by the size of the rocked fairing, the large-diameter spaceborne antenna is required to be small mass and have a deployment function. After being orbited, the antenna can be deployed by expanding and be stabilized. However, few types of structures can be used to construct large cylindrical shell structures in existing structures, which greatly limits the development and application of such antennas. Aiming at high structural efficiency, the geometrical characteristics of parabolic cylinders and mechanism topological mapping law to the expandable truss are studied, and the basic configuration of deployable truss with cylindrical shell is structured. Then a modular truss parabolic cylindrical antenna is designed in this paper. The antenna has the characteristics of stable structure, high precision of reflecting surface formation, controllable motion process, high storage rate, and lightweight, etc. On the basis of the overall configuration comprehensive theory and optimization method, the structural stiffness of the modular truss parabolic cylindrical antenna is improved. And the bearing density and impact resistance of support structure are improved based on the internal tension optimal distribution method of reflector forming. Finally, a truss-type cylindrical deployable support structure with high constriction-deployment ratio, high stiffness, controllable deployment, and low mass is successfully developed, laying the foundation for the application of large-diameter parabolic cylindrical antennas in satellite antennas.

Keywords: linear array feed antenna, truss type, parabolic cylindrical antenna, spaceborne antenna

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Authors: Yu-Jia Jian, Emily Chia-Yu Su, Hui-Ling Hsu, Jian-Jhih Chen

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Coronary artery is the major supplier of myocardial blood flow. When fat and cholesterol are deposit in the coronary arterial wall, narrowing and stenosis of the artery occurs, which may lead to myocardial ischemia and eventually infarction. According to the World Health Organization (WHO), estimated 740 million people have died of coronary heart disease in 2015. According to Statistics from Ministry of Health and Welfare in Taiwan, heart disease (except for hypertensive diseases) ranked the second among the top 10 causes of death from 2013 to 2016, and it still shows a growing trend. According to American Heart Association (AHA), the risk factors for coronary heart disease including: age (> 65 years), sex (men to women with 2:1 ratio), obesity, diabetes, hypertension, hyperlipidemia, smoking, family history, lack of exercise and more. We have collected a dataset of 421 patients from a hospital located in northern Taiwan who received coronary computed tomography (CT) angiography. There were 300 males (71.26%) and 121 females (28.74%), with age ranging from 24 to 92 years, and a mean age of 56.3 years. Prior to coronary CT angiography, basic data of the patients, including age, gender, obesity index (BMI), diastolic blood pressure, systolic blood pressure, diabetes, hypertension, hyperlipidemia, smoking, family history of coronary heart disease and exercise habits, were collected and used as input variables. The output variable of the prediction module is the degree of coronary artery stenosis. The output variable of the prediction module is the narrow constriction of the coronary artery. In this study, the dataset was randomly divided into 80% as training set and 20% as test set. Four machine learning algorithms, including logistic regression, stepwise regression, neural network and decision tree, were incorporated to generate prediction results. We used area under curve (AUC) / accuracy (Acc.) to compare the four models, the best model is neural network, followed by stepwise logistic regression, decision tree, and logistic regression, with 0.68 / 79 %, 0.68 / 74%, 0.65 / 78%, and 0.65 / 74%, respectively. Sensitivity of neural network was 27.3%, specificity was 90.8%, stepwise Logistic regression sensitivity was 18.2%, specificity was 92.3%, decision tree sensitivity was 13.6%, specificity was 100%, logistic regression sensitivity was 27.3%, specificity 89.2%. From the result of this study, we hope to improve the accuracy by improving the module parameters or other methods in the future and we hope to solve the problem of low sensitivity by adjusting the imbalanced proportion of positive and negative data.

Keywords: decision support, computed tomography, coronary artery, machine learning

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Authors: Abhishek Sharma, Arnab Banerjee

Abstract:

The research is intended to study the solar electric propulsion (SEP) technology for planetary missions. The main benefits of using solar electric propulsion for such missions are shorter flight times, more frequent target accessibility and the use of a smaller launch vehicle than that required by a comparable chemical propulsion mission. Energized by electric power from on-board solar arrays, the electrically propelled system uses 10 times less propellant than conventional chemical propulsion system, yet the reduced fuel mass can provide vigorous power which is capable of propelling robotic and crewed missions beyond the Lower Earth Orbit (LEO). The various thrusters used in the SEP are gridded ion thrusters and the Hall Effect thrusters. The research is solely aimed to study the ion thrusters and investigate the complications related to it and what can be done to overcome the glitches. The ion thrusters are used because they are found to have a total lower propellant requirement and have substantially longer time. In the ion thrusters, the anode pushes or directs the incoming electrons from the cathode. But the anode is not maintained at a very high potential which leads to divergence. Divergence leads to the charges interacting against the surface of the thruster. Just as the charges ionize the xenon gases, they are capable of ionizing the surfaces and over time destroy the surface and hence contaminate it. Hence the lifetime of thruster gets limited. So a solution to this problem is using substances which are not easy to ionize as the surface material. Another approach can be to increase the potential of anode so that the electrons don’t deviate much or reduce the length of thruster such that the positive anode is more effective. The aim is to work on these aspects as to how constriction of the deviation of charges can be done by keeping the input power constant and hence increase the lifetime of the thruster. Predominantly ring cusp magnets are used in the ion thrusters. However, the study is also intended to observe the effect of using solenoid for producing micro-solenoidal magnetic field apart from using the ring cusp magnetic field which are used in the discharge chamber for prevention of interaction of electrons with the ionization walls. Another foremost area of interest is what are the ways by which power can be provided to the Solar Electric Propulsion Vehicle for lowering and boosting the orbit of the spacecraft and also provide substantial amount of power to the solenoid for producing stronger magnetic fields. This can be successfully achieved by using the concept of Electro-dynamic tether which will serve as a power source for powering both the vehicle and the solenoids in the ion thruster and hence eliminating the need for carrying extra propellant on the spacecraft which will reduce the weight and hence reduce the cost of space propulsion.

Keywords: electro-dynamic tether, ion thruster, lifetime of thruster, solar electric propulsion vehicle

Procedia PDF Downloads 179

Authors: Sarah F. M. Pilati, Carolina S. Flausino, Guilherme F. Hoffmeister, Davi R. Tames, Telmo J. Mezadri

Abstract:

The effects that may be related to narghile smoking in the tissues of the oral cavity, trachea and lung and associated inflammation has been the question raised lately. The objective of this study was to identify histopathological changes and the presence of inflammation through the exposure of mice to narghile smoking through a whole-body study. The animals were divided in 4 groups with 5 animals in each group, being: one control group, one with 7 days of exposure, 15 days and the last one with 30 days. The animals were exposed to the conventional hookah smoke from Mizo brand with 0.5% percentage of unwashed tobacco and the EcOco brand coconut fiber having a dimension of 2cm × 2cm. The duration of the session was 30 minutes / day per 7, 15 and 30 days. The tobacco smoke concentration at which test animals were exposed was 35 ml every two seconds while the remaining 58 seconds were pure air. Afterward, the mice were sacrificed and submitted to histological evaluation through slices. It was found in the tongue of the 7-day group the presence in epithelium areas with acanthosis, hyperkeratosis and epithelial projections. In-depth, more intense inflammation was observed. All alteration processes increased significantly as the days of exposure increased. In trachea, with the 7-day group, there was a decrease in thickening of the pseudostratified epithelium and a slight decrease in lashes, giving rise to the metaplasia process, a process that was established in the 31-day sampling when the epithelium became stratified. In the conjunctive tissue, it was observed the presence of defense cells and formation of new vessels, evidencing the chronic inflammatory process, which decreased in the course of the samples due to the deposition of collagen fibers as seen in the 15 and 31 days groups. Among the structures of the lung, the study focused on the bronchioles and alveoli. From the 7-day group, intra-alveolar septum thickness increased, alveolar space decreased, inflammatory infiltrate with mononuclear and defense cells and new vessels formation were observed, increasing the number of red blood cells in the region. The results showed that with the passing of the days a progressive increase of the signs of changes in the region was observed, a factor that shows that narghile smoking stimulates alterations mainly in the alveoli (place where gas exchanges occur that should not present alterations) calling attention to the harmful and aggressive effect of narghile smoking. These data also highlighted the harmful effect of smoking, since the presence of acanthosis, hyperkeratosis, epithelial projections and inflammation evidences the cellular alteration process for the tongue tissue protection. Also, the narghile smoking stimulates both epithelial and inflammatory changes in the trachea, in addition to a process of metaplasia, a factor that reinforces the harmful effect and the carcinogenic potential of the narghile smoking.

Keywords: metaplasia, inflammation, pathological constriction, hyperkeratosis

Procedia PDF Downloads 142