Search results for: internal combustion engines

Authors: Beatriz Delgado

Abstract:

Although social anxiety is one of the most prevalent disorders in adolescents and causes considerable difficulties and social distress in those with the disorder, to date very few studies have explored the impact of social anxiety on academic adjustment in student populations. The aim of this study was analyze the effect of social anxiety on school functioning in Secondary Education. Specifically, we examined the relationship between social anxiety and self-concept, academic goals, causal attributions, intellectual aptitudes, and learning strategies, personality traits, and academic performance, with the purpose of creating a causal-explanatory model of academic performance. The sample consisted of 2,022 students in the seven to ten grades of Compulsory Secondary Education in Spain (M = 13.18; SD = 1.35; 51.1% boys). We found that: (a) social anxiety has a direct positive effect on internal attributional style, and a direct negative effect on self-concept. Social anxiety also has an indirect negative effect on internal causal attributions; (b) prior performance (first academic trimester) exerts a direct positive effect on intelligence, achievement goals, academic self-concept, and final academic performance (third academic trimester), and a direct negative effect on internal causal attributions. It also has an indirect positive effect on causal attributions (internal and external), learning goals, achievement goals, and study strategies; (c) intelligence has a direct positive effect on learning goals and academic performance (third academic trimester); (d) academic self-concept has a direct positive effect on internal and external attributional style. Also, has an indirect effect on learning goals, achievement goals, and learning strategies; (e) internal attributional style has a direct positive effect on learning strategies and learning goals. Has a positive but indirect effect on achievement goals and learning strategies; (f) external attributional style has a direct negative effect on learning strategies and learning goals and a direct positive effect on internal causal attributions; (g) learning goals have direct positive effect on learning strategies and achievement goals. The structural equation model fit the data well (CFI = .91; RMSEA = .04), explaining 93.8% of the variance in academic performance. Finally, we emphasize that the new causal-explanatory model proposed in the present study represents a significant contribution in that it includes social anxiety as an explanatory variable of cognitive-motivational constructs.

Keywords: academic performance, adolescence, cognitive-motivational variables, social anxiety

Procedia PDF Downloads 327

Authors: Rakesh Mishra, Mukunda Upadhyay, Rajni Singh

Abstract:

This paper attempts to link remittances sent by internal as well as international out-migrants and its domestic preferences of usage in three different dimension of Household level development in India and its states. Investment of remittances in these sectors reveals for mixed choices of preferential among the states from where people have out-migrated. The multivariate analysis implies that among all three indicators of human development, health (Investment in Food and Health) is the one that attracts the major investment followed by capital formation and least on Education. Usage of the remittances has been found to be varying across all the states in India as far as usage in health, capital formation and education are concerned. Orissa, Nagaland, Madhya Pradesh, Jharkhand, Gujarat, D & H Haweli are some of the states and union territory that contributes highest of its international remittances on health, while most of the usage of the internal remittances has second or third preferences of investment on the health except for Uttar Pradesh, D & H Haweli, Arunachal Pradesh and A & N Is. This paper tries to access usage of international remittances as well as internal remittances on the flow of remittances at the micro level and its implications across three basic determinants of Human Development that is Health, Capital formation and Education coupled with the preferences of usage in presence of Several Socio economic and Demographic variable.

Keywords: multivariate analysis, household development, remittances, internal and international migration

Procedia PDF Downloads 441

Authors: Muhammad Asghar, Aamer Iqbal Bhatti, Qadeer Ahmed, Tahir Izhar

Abstract:

Three wheeler auto Rickshaw, often termed as ‘auto rickshaw’ is very common in Pakistan and is considered as the most affordable means of transportation to the local people. Problems caused by the gasoline engine on the environment and people, the researchers and the automotive industry have turned to the hybrid electric vehicles and electrical powered vehicle. The research in this paper explains the design of energy efficient Electric auto Rickshaw. An electric auto rickshaw is being developed at Center for Energy Research and Development, (Lahore), which is running on the roads of Lahore city. Energy storage capacity of batteries is at least 25 times heavier than fossil fuel and having volume 10 times in comparison to fuel, resulting an increase of the Rickshaw weight. A set of specifications is derived according to the mobility requirements of the electric auto rickshaw. The design choices considering the power-train and component selection are explained in detail. It was concluded that electric auto rickshaw has many advantages and benefits over the conventional auto rickshaw. It is cleaner and much more energy efficient but limited to the distance it can travel before recharging of battery. In addition, a brief future view of the battery technology is given.

Keywords: conventional auto rickshaw, energy efficiency, electric auto rickshaw, internal combustion engine, environment

Procedia PDF Downloads 281

Authors: Yozna Gurung

Abstract:

This paper presents preliminary findings from an on-going study on the use of Internal State Terms (IST) in the production of narratives of Hindi-English bilinguals in an attempt to identify children at risk for Specific Language Impairment. Narratives were examined for macrostructure (story structure and story complexity) and internal state terms or mental state terms (IST/MST). 31 students generated stories based on six pictures that were matched for content and story structure in L1 (Hindi) and L2 (English) using a wordless picture narrative. From 30 sample population, 2 students are at risk of Specific Language Impairment, according to this study i.e 6.45%. They showed least development in story grammar as well as IST in both their languages.

Keywords: internal state terms, macrostructure, specific language impairment, wordless picture narrative

Procedia PDF Downloads 226

Authors: A. D. Rao, Sachiko Mohanty

Abstract:

The Internal Waves (IWs) are generated by the flow of barotropic tide over the rapidly varying and steep topographic features like continental shelf slope, subsurface ridges, and the seamounts, etc. The IWs of the tidal frequency are generally known as internal tides. These waves have a significant influence on the vertical density and hence causes mixing in the region. Such waves are also important in submarine acoustics, underwater navigation, offshore structures, ocean mixing and biogeochemical processes, etc. over the shelf-slope region. The seasonal variability of internal tides in the Bay of Bengal with special emphasis on its energetics is examined by using three-dimensional MITgcm model. The numerical simulations are performed for different periods covering August-September, 2013; November-December, 2013 and March-April, 2014 representing monsoon, post-monsoon and pre-monsoon seasons respectively during which high temporal resolution in-situ data sets are available. The model is initially validated through the spectral estimates of density and the baroclinic velocities. From the estimates, it is inferred that the internal tides associated with semi-diurnal frequency are more dominant in both observations and model simulations for November-December and March-April. However, in August, the estimate is found to be maximum near-inertial frequency at all the available depths. The observed vertical structure of the baroclinic velocities and its magnitude are found to be well captured by the model. EOF analysis is performed to decompose the zonal and meridional baroclinic tidal currents into different vertical modes. The analysis suggests that about 70-80% of the total variance comes from Mode-1 semi-diurnal internal tide in both observations as well as in the model simulations. The first three modes are sufficient to describe most of the variability for semidiurnal internal tides, as they represent 90-95% of the total variance for all the seasons. The phase speed, group speed, and wavelength are found to be maximum for post-monsoon season compared to other two seasons. The model simulation suggests that the internal tide is generated all along the shelf-slope regions and propagate away from the generation sites in all the months. The model simulated energy dissipation rate infers that its maximum occurs at the generation sites and hence the local mixing due to internal tide is maximum at these sites. The spatial distribution of available potential energy is found to be maximum in November (20kg/m²) in northern BoB and minimum in August (14kg/m²). The detailed energy budget calculation are made for all the seasons and results are analysed.

Keywords: available potential energy, baroclinic energy flux, internal tides, Bay of Bengal

Procedia PDF Downloads 164

Authors: Fatemeh Alsadat Borhani, Hassan Heydari, Mansour Abdi

Abstract:

The purpose of this study to determine the effectiveness of group therapy with approach reality therapy in reducing symptoms of anxiety and increased self- esteem and internal control of infertile women. The population of this study is all infertile women in Qom city in 2012 that with the use of purposeful sampling, 32 individuals were selected as sample. 16 individuals of infertile women in the control group and 16 infertile women in the experimental group is replaced. The research design was of type quasi-experimental with design pretest-posttest with control group. Thus, infertile women were randomly appointed in the experimental and control groups. Also, in this study data through normalized questionnaires, the Beck Anxiety scale, Rotter's Locus of control inventory, Cooper Smith self-esteem inventory was collected. For analysis of data, descriptive statistics, mean, standard deviation and inferential statistics, one way analysis of covariance model with SPSS version 20 software was used. The findings indicated that intervention of the group therapy with approach reality therapy in experimental group reduced symptoms of anxiety and mutually increased self-esteem and internal control in infertile women of experimental group.

Keywords: reality therapy, infertile women, anxiety, self esteem, internal control

Procedia PDF Downloads 568

Authors: Farhana Tarannum

Abstract:

Ambient (outdoor) air pollution is now recognized as an important problem, both nationally and worldwide. The concentrations of gaseous pollutants (SOx, NOx, CO and O3) have been determined from samples collected at Kallyanpur along Shamoli corridor in Dhaka city. Pollutants were determined in a sample collected at ground level and a roof of a 7-storied building. These pollutants are emitted largely from stationary sources like fossil fuel fired power plants, industrial plants, and manufacturing facilities as well as mobile sources. The incomplete combustion of fuel, wood and the Sulphur containing fuel used in the vehicles are one of the main causes of CO and SOx respectively in our natural environment. When the temperature of combustion in high enough and some of that nitrogen reacts with oxygen in the air, various nitrogen oxides (NOx) are then formed. The VOCs react with NOx in the presence of sunlight to form O3. UV Visible spectrophotometric method has been used for the determination of SOx, NOx and O3. The sensor type device was used for the estimation of CO. It was found that the air pollutants (CO, SOx, NOx and O3) of a sample collected at the roof of a building were lower compared to the ground level; it indicated that ground level people are mostly affected by the gaseous pollutants.

Keywords: gaseous pollutants, UV-visible spectrophotometry, ambient air quality, Dhaka city

Procedia PDF Downloads 343

Authors: Fatih Suleyman Taskincan, Ahmet Karaarslan

Abstract:

In this article, the study and analysis of Single Ended Primary Inductance Converter (SEPIC) are presented for battery charging applications that will be used in military applications. The usage of this kind of converters come from its advantage of non-reverse polarity at outputs. As capacitors charge and discharge through inductance, peak current does not occur on capacitors. Therefore, the efficiency will be high compared to buck-boost converters. In this study, the converter (SEPIC) is designed to be operated with Internal Model Controller (IMC). The traditional controllers like Proportional Integral Controller are not preferred as its linearity behavior. Hence IMC is designed for this converter. This controller is a model-based control and provides more robustness and better set point monitoring. Moreover, it can be used for an unstable process where the conventional controller cannot handle the dynamic operation. Matlab/Simulink environment is used to simulate the converter and its controller, then, the results are shown and discussed.

Keywords: DC/DC converter, single ended primary inductance converter, SEPIC, internal model controller, IMC, switched mode power supply

Procedia PDF Downloads 622

Authors: Waseem Al-Talalwah

Abstract:

The superior vesical artery usually arises directly from the anterior division of the internal iliac artery. It may arise from the umbilical artery as three or four branches to supply the upper and middle parts of bladder. Current study focuses on the different origins of the superior vesical artery to provide a sufficient data for surgeons to disease iatrogenic fault. The superior vesical artery arises directly from the anterior division of the internal iliac artery in 24.5% whereas it arises indirectly as from umbilical artery in 83.7%. Further, it may arise from any branch of the anterior division as from the utrine and obturator arteries in 6.1% and in 6.3% respectively. It also shares the origin of the internal pudendal and inferior glutyeal artery as it arises from the gluteopudendal trunk in 4.1%. The superior vesical artery arises as a single, double, triple and quadruple in 69.4%, 20.4%, 8.2% and 2% respectively. In case of cystectomy for bladder cancer, surgeons have to be aware of the origin variability of superior vesical artery to prevent post-surgical complication such as intra-pelvic bleeding. Also, the as intra-pelvic bleeding has to be expected in case of hysterectomy therefore a great caution of the vesical branches arising from uterine artery has to be considered. In case of aneurysm resection of inferior gluteal artery arising from the gluteopudendal trunk, the surgeons have to be careful of the vascular supply of urinary bladder coming from above and below this common trunk as from superior and inferior vesical arteries respectively. Therefore, present study increases the awareness of clinical significance of superior vesical artery origin for surgeons to minimise the iatroginc errors.

Keywords: superior vesical artery, anterior division, internal iliac, internal pudendal, inferior glutyeal, intra-pelvic bleeding, hysterectomy, cystectomy

Procedia PDF Downloads 384

Authors: Felipe J. Costa, João F. A. Martos, Ronaldo L. Cardoso, Israel S. Rêgo, Marco A. S. Minucci, Antonio C. Oliveira, Paulo G. P. Toro

Abstract:

The Prof. Henry T. Nagamatsu Laboratory of Aerothermodynamics and Hypersonics, at the Institute for Advanced Studies designed the Brazilian 14-X Hypersonic Aerospace Vehicle, which is a technological demonstrator endowed with two innovative technologies: waverider technology, to obtain lift from conical shockwave during the hypersonic flight; and uses hypersonic airbreathing propulsion system called scramjet that is based on supersonic combustion, to perform flights on Earth's atmosphere at 30 km altitude at Mach numbers 7 and 10. The scramjet is an aeronautical engine without moving parts that promote compression and deceleration of freestream atmospheric air at the inlet through the conical/oblique shockwaves generated during the hypersonic flight. During high speed flight, the shock waves and the viscous forces yield the phenomenon called aerodynamic heating, where this physical meaning is the friction between the fluid filaments and the body or compression at the stagnation regions of the leading edge that converts the kinetic energy into heat within a thin layer of air which blankets the body. The temperature of this layer increases with the square of the speed. This high temperature is concentrated in the boundary-layer, where heat will flow readily from the boundary-layer to the hypersonic aerospace vehicle structure. Fay and Riddell and Eckert methods are applied to the stagnation point and to the flat plate segments in order to calculate the aerodynamic heating. On the understanding of the aerodynamic heating it is important to analyze the heat conduction transfer to the 14-X waverider internal structure. ANSYS Workbench software provides the Thermal Numerical Analysis, using Finite Element Method of the 14-X waverider unpowered scramjet at 30 km altitude at Mach number 7 and 10 in terms of temperature and heat flux. Finally, it is possible to verify if the internal temperature complies with the requirements for embedded systems, and, if is necessary to do modifications on the structure in terms of wall thickness and materials.

Keywords: aerodynamic heating, hypersonic, scramjet, thermal analysis

Procedia PDF Downloads 444

Authors: Nelson Igaba, C. Onaga, S. Hlongwane

Abstract:

Background: Medical Male Circumcision (MMC) is part of a comprehensive HIV prevention strategy. The quality of MMC done at Right To Care (RtC) sites is maintained by Continuous Quality Improvement (CQI) based on findings of assessments by internal and independent external assessors who evaluate such parameters as the quality of the surgical procedure, infection control, etc. There are 12 RtC MMC teams in Mpumalanga, two of which are headed by Medical Officers and 10 by Clinical Associates (Clin A). Objectives: To compare the quality (i) of care rendered at doctor headed sites (DHS) versus Clin A headed sites (CHS); (ii) of CQI assessments (external versus internal). Methodology: A retrospective review of data from RightMax™ (a novel RtC data management system) and CQI reports (external and internal) was done. CQI assessment scores of October 2015 and October 2016 were taken as the baseline and latest respectively. Four sites with 745-810 circumcisions per annum were purposively selected; the two DHS (group A) and two CHS (group B). Statistical analyses were conducted using R (2017 version). Results: There were no significant difference in latest CQI scores between the two groups (DHS and CHS) (Anova, F = 1.97, df = 1, P = 0.165); between internal and external CQI assessment scores (Anova, F = 2.251, df = 1, P = 0.139) or among the individual sites (Anova, F = 1.095, df = 2, P = 0.341). Of the total of 16 adverse events reported by the four sites in the 12 months reviewed (all were infections), there was no statistical evidence that the documented severity of the infection was different for DHS and CHS (Fisher’s exact test, p-value = 0.269). Conclusion: At RtC VMMC sites in Mpumalanga, internal and external/independent CQI assessments are comparable, and quality of care of VMMC is standardized with the performance of well-supervised clinical associates comparing well with those of medical officers.

Keywords: adverse events, Right to Care, male medical circumcision, continuous quality improvement

Procedia PDF Downloads 167

Authors: P. Makendran, M. Pragadeesh, N. Narash, N. Manikandan, A. Rajasri, V. Sanal Kumar

Abstract:

The growing severity of government-obligatory emissions legislation has required continuous improvement in catalysts performance and the associated reactor systems. IC engines emit a lot of harmful gases into the atmosphere. These gases are toxic in nature and a catalytic converter is used to convert these toxic gases into less harmful gases. The catalytic converter converts these gases by Oxidation and reduction reaction. Stoichiometric engines usually use the three-way catalyst (TWC) for simultaneously destroying all of the emissions. CO and NO react to form CO2 and N2 over one catalyst, and the remaining CO and HC are oxidized in a subsequent one. Literature review reveals that typically precious metals are used as a catalyst. The actual reactor is composed of a washcoated honeycomb-style substrate, with the catalyst being contained in the washcoat. The main disadvantage of a catalytic converter is that it exerts a back pressure to the exhaust gases while entering into them. The objective of this paper is to optimize the back pressure developed by the catalytic converter through geometric optimization of catalystic converter. This can be achieved by designing a catalyst with a optimum cone angle and a more surface area of the catalyst substrate. Additionally, the arrangement of the pores in the catalyst substrate can be changed. The numerical studies have been carried out using k-omega turbulence model with varying inlet angle of the catalytic converter and the length of the catalyst substrate. We observed that the geometry optimization is a meaningful objective for the lucrative design optimization of a catalytic converter for industrial applications.

Keywords: catalytic converter, emission control, reactor systems, substrate for emission control

Procedia PDF Downloads 899

Authors: Joudia Akil, Stephane Siffert, Laurence Pirault-Roy, Renaud Cousin, Christophe Poupin

Abstract:

The CO2 emitted from anthropic activities is perceived as a constraint in industrial activity due to taxes, stringent environmental regulations, impact on global warming… To limit these CO2 emissions, reuse of CO2 represents a promising alternative, with important applications in chemical industry and for power generation. However, CO2 valorization process requires a gas as pure as possible Oxyfuel-combustion that enables obtaining a CO2 rich stream, with water vapor (10%) is then interesting. Nevertheless to decrease the amount of the by-products found with the CO2 (especially CO and NOx which are harmful to the environment) a catalytic treatment must be applied. Nowadays three-way catalysts are well-developed material for simultaneous conversion of unburned hydrocarbons, carbon monoxide (CO) and nitrogen oxides (NOx). The use of Pd attracted considerable attention on the basis of economic factors (the high cost and scarcity of Pt and Rh). This explains the large number of studies concerning the CO-NO reaction on Pd in the recent years. In the present study, we will compare a series of Pd materials supported on different oxides for CO2 purification from the oxyfuel combustion system, by reducing NO with CO in an oxidizing environment containing CO2 rich stream and presence of 8.2% of water. Al2O3, CeO2, MgO, SiO2 and TiO2 were used as support materials of the catalysts. 1wt% Pd/Support catalysts were obtained by wet impregnation on supports with a precursor of palladium [Pd(acac)2]. The obtained samples were subsequently characterized by H2 chemisorption, BET surface area and TEM. Finally, their catalytic performances were evaluated in CO2 purification which is carried out in a fixed-bed flow reactor containing 150 mg of catalyst at atmospheric pressure. The flow of the reactant gases is composed of: 20% CO2, 10% O2, 0.5% CO, 0.02% NO and 8.2% H2O (He as eluent gas) with a total flow of 200mL.min−1, in the same GHSV. The catalytic performance of the Pd catalysts for CO2 purification revealed that: -The support material has a strong influence on the catalytic activity of 1wt.% Pd supported catalysts. depending of the nature of support, the Pd-based catalysts activity changes. -The highest reduction of NO with CO is obtained in the following ranking: TiO2>CeO2>Al2O3. -The supports SiO2 and MgO should be avoided for this reaction, -Total oxidation of CO occurred over different materials, -CO2 purification can reach 97%, -The presence of H2O has a positive effect on the NO reduction due to the production of the reductant H2 from WGS reaction H2O+CO → H2+CO2

Keywords: carbon dioxide, environmental chemistry, heterogeneous catalysis, oxyfuel combustion

Procedia PDF Downloads 251

Authors: Gourida Siham

Abstract:

Chinese society has witnessed a continuing trend of nationwide rural to urban migration since the 1970's. Before that age, under restricted hukou systems, peasants were kept still and fixed in the farm land. The year 1978 and later years saw the control of migration in China was relaxed gradually, freeing peasants to start their own businesses and reach out to work also in urban areas. Since then the “floating population” (migrants without local hukou) took great momentum and drew great attention from both the media and academia. The scale of such internal migration is enormous –the floating population has reached to a number of 79 million in 2000, and as of 2010, the number of migrant workers from rural China amounts to over 221 million and according to the annual survey results projections by National Bureau of Statistics; the total migrant workers in china in 2012 amounted to 262.61 million, which refers to an increase of 9.83 million compared with the previous year with increase percentage by 3.9%. Using China’s Jiangxi Province as a case, this paper examines patterns of internal migration as a response of emigrations in the context of high emigration communities. Our findings suggest that emigration of individuals initially deterred both inter-provincial and intra- provincial migration of other family members, and yet, overtime they had an increasing propensity to migrate internally at both scales.

Keywords: internal migration, jiangxi, nanchang, remittances

Procedia PDF Downloads 398

Authors: Hakim S. Sultan Aljibori

Abstract:

An experimental procedure is developed to study the performance of composite thin wall cylinders subjected to internal pressure loading for investigations of stress distribution through the composite cylinders wall. Three types of fibers were used in this study are; woven roving glass fiber/epoxy, hybrid fiber/epoxy, and Kevlar fiber/epoxy composite specimens were fabricated and tested. All of these specimens subjected to uniformed pressure load using the hydraulic pump. Axial stress is identified, and values were found after collecting all the results. Comparison between the deferent types of specimens was done. Thus, the present investigation concludes the efficient and effective composite cylinder experimentally and provides a considerable advantage for using woven roving fibers in pressure vessels applications.

Keywords: stress distribution, composite material, internal pressure, glass fiber, hybrid fiber

Procedia PDF Downloads 155

Authors: Mansur Lubabah Kwanbo

Abstract:

Existing literatures have demonstrated the importance of executive duality (ED) and audit committee (AC) in the financial growth of companies. To some extent this points to corporate governance mechanism aiming at addressing makers and implementers of company policies to be centered on promoting only company objectives. However, furthering organizational objectives needs an adequate structure of control to realize that. Recent development in the various industries in Nigeria have indicated the internal control system (ICS)has not been able to adequately address most of the activities that results in ills of sustaining growth for these industries. It is from this premise the study has as one of its objective to determine the extent to which ICS significantly relates to ED and AC in listed Nigerian corporation. Data were sourced from 308 financial statements and accounts of the corporations that made the sample of the study. Logistic regression aided the test of the hypothesis formulated for the study. Findings revealed a significant relationship between the study variables. The study concludes that the internal control system (ICS) is effective despite the bifurcation of executive duality (ED) and the presence of the Audit Committee (AC) to the extent of preventing ills that encourage lack of sustainability of company’s growth. Sustaining legitimate policies that translate into huge earnings, and create value to stake holders should be pursued.

Keywords: audit committee (AC), executive duality (ED), internal control system (ICS), Nigeria

Procedia PDF Downloads 289

Authors: Aakash Kumar R. G., Anees K. Ahamed, Raj M. Mohan

Abstract:

Effective engine cooling can improve the engine’s life and efficacy. The design of the fin of the cylinder head and block determines the cooling mechanism of air cooled engine. The heat conduction takes place through the engine parts and convection of heat from the surface of the fins takes place with air as the heat transferring medium. The air surrounding the cooling fins helps in removal of heat built up by the air cooled engine. If the heat removal rate is inadequate, it will result in lower engine efficiency and high thermal stresses in the engine. The main drawback of the air cooled engine is the low heat transfer rate of the cooling fins .This work is based on scrutiny of previous researches that involves enhancing of heat transfer rate of cooling fins. The current research is about augmentation of heat transfer rate of longitudinal rectangular fin profiles by varying the length of the fin and diameter of holes on the fins. Thermal and flow analysis is done for two different models of fins. One is simple fin without holes and the other is perforated (consist of holes). It can be inferred from the research that the fins with holes have a higher fin efficiency than the fins without holes. The geometry of the fin is done in CREO. The heat transfer analysis is done using ANSYS software.

Keywords: fins, heat transfer, perforated fins, thermal analysis, thermal flux

Procedia PDF Downloads 367

Authors: Vidula Shevade, B. J. Nagare, Sajeev Chacko

Abstract:

First principles simulation, meaning density functional theory (DFT) calculations with plane waves and pseudopotential, has become a prized technique in condensed matter theory. Nanoparticles (NP) have been known to possess good catalytic activities, especially for molecules such as CO, O₂, etc. Among the metal NPs, Aluminium based NPs are also widely known for their catalytic properties. Aluminium metal is a lightweight, excellent electrical, and thermal abundant chemical element in the earth’s crust. Aluminium NPs, when added to solid rocket fuel, help improve the combustion speed and considerably increase combustion heat and combustion stability. Adding aluminium NPs into normal Al/Al₂O₃ powder improves the sintering processes of the ceramics, with high heat transfer performance, increased density, and enhanced thermal conductivity of the sinter. We used VASP and Gaussian 0₃ package to compute the geometries, electronic structure, and bonding properties of Al₁₂Ni as well as its interaction with O₂ and CO molecules. Several MD simulations were carried out using VASP at various temperatures from which hundreds of structures were optimized, leading to 24 unique structures. These structures were then further optimized through a Gaussian package. The lowest energy structure of Al₁₂Ni has been reported to be a singlet. However, through our extensive search, we found a triplet state to be lower in energy. In our structure, the Ni atom is found to be on the surface, which gives the non-zero magnetic moment. Incidentally, O2 and CO molecules are also triplet in nature, due to which the Al₁₂-Ni cluster is likely to facilitate the oxidation process of the CO molecule. Our results show that the most favourable site for the CO molecule is the Ni atom and that for the O₂ molecule is the Al atom that is nearest to the Ni atom. Al₁₂Ni-O₂ and Al₁₂-Ni-CO structures we extracted using VMD. Al₁₂Ni nanocluster, due to in triplet electronic structure configuration, indicates it to be a potential candidate as a catalyst for oxidation of CO molecules.

Keywords: catalyst, gaussian, nanoparticles, oxidation

Procedia PDF Downloads 91

Authors: J. H. Park, R. H. Hwang, K. B. Yi

Abstract:

Carbon Capture and Storage (CCS) is one of the important technology to reduce the CO₂ emission from large stationary sources such as a power plant. Among the carbon technologies for power plants, chemical looping combustion (CLC) has attracted much attention due to a higher thermal efficiency and a lower cost of electricity. A CLC process is consists of a fuel reactor and an air reactor which are interconnected fluidized bed reactor. In the fuel reactor, an oxygen carrier (OC) is reduced by fuel gas such as CH₄, H₂, CO. And the OC is send to air reactor and oxidized by air or O₂ gas. The oxidation and reduction reaction of OC occurs between the two reactors repeatedly. In the CLC system, high concentration of CO₂ can be easily obtained by steam condensation only from the fuel reactor. It is very important to understand the oxidation and reduction characteristics of oxygen carrier in the CLC system to determine the solids circulation rate between the air and fuel reactors, and the amount of solid bed materials. In this study, we have conducted the experiment and interpreted oxidation and reduction reaction characteristics via observing weight change of Ni-based oxygen carrier using the TGA with varying as concentration and temperature. Characterizations of the oxygen carrier were carried out with BET, SEM. The reaction rate increased with increasing the temperature and increasing the inlet gas concentration. We also compared experimental results and adapted basic reaction kinetic model (JMA model). JAM model is one of the nucleation and nuclei growth models, and this model can explain the delay time at the early part of reaction. As a result, the model data and experimental data agree over the arranged conversion and time with overall variance (R²) greater than 98%. Also, we calculated activation energy, pre-exponential factor, and reaction order through the Arrhenius plot and compared with previous Ni-based oxygen carriers.

Keywords: chemical looping combustion, kinetic, nickel-based, oxygen carrier, spray drying method

Procedia PDF Downloads 203

Authors: Prateek Sharma, Venkata Ramachandrarao Maddali, Kapil Kukreja, B. N. Mohapatra

Abstract:

Waste management is one of the pressing issues of India. Several initiatives by the Indian Government, including the recent one “Swachhata hi Seva” campaign launched by Prime Minister on 15th August 2018, can be one of the game changers to waste disposal. Under this initiative, the government, cement industry and other stakeholders are working hand in hand to dispose of single-use plastics in cement plants in rotary kilns. This is an exemplary effort and a move that establishes the Indian Cement industry as one of the key players in a circular economy. One of the cement plants in Southern India has been mandated by the state government to co-process shredded plastic and refuse-derived fuel (RDF) available in nearby regions as an alternative fuel in their cement plant. The plant has set a target of 25 % thermal substitution rate (TSR) by RDF in the next five years. Most of the cement plants in India and abroad have achieved high TSR through pre calciner firing. But the cement plant doesn’t have the precalciner and has to achieve this daunting task of 25 % TSR by firing through the main kiln burner. Since RDF is a heterogeneous waste with the change in fuel quality, it is difficult to achieve this task; hence plant has to resort to firing some portion of RDF/plastics at kiln inlet. But kiln inlet has reducing conditions as observed during measurements) under baseline condition. The combustion behavior of RDF of different sizes at different firing locations in riser was studied with the help of a computational fluid dynamics tool. It has been concluded that RDF above 50 mm size results in incomplete combustion leading to CO formation. Moreover, best firing location appears to be in the bottom portion of the kiln riser.

Keywords: kiln inlet, plastics, refuse derived fuel, thermal substitution rate

Procedia PDF Downloads 119

Authors: Minoo Ghasemzadeh, Rouzbeh Riazi, Shidvash Vakilipour, Alireza Ramezani

Abstract:

In this study, thermo acoustic oscillations of a lean premixed combustor has been investigated, and a mono-dimensional code was developed in this regard. The linearized equations of motion are solved for perturbations with time dependence〖 e〗^iwt. Two flame models were considered in this paper and the effect of mean flow and boundary conditions were also investigated. After manipulation of flame heat release equation together with the equations of flow perturbation within the main components of the combustor model (i.e., plenum/ premixed duct/ and combustion chamber) and by considering proper boundary conditions between the components of model, a system of eight homogeneous equations can be obtained. This simplification, for the main components of the combustor model, is convenient since low frequency acoustic waves are not affected by bends. Moreover, some elements in the combustor are smaller than the wavelength of propagated acoustic perturbations. A convection time is also assumed to characterize the required time for the acoustic velocity fluctuations to travel from the point of injection to the location of flame front in the combustion chamber. The influence of an extended flame model on the acoustic frequencies of combustor was also investigated, assuming the effect of flame speed as a function of equivalence ratio perturbation, on the rate of flame heat release. The abovementioned system of equations has a related eigenvalue equation which has complex roots. The sign of imaginary part of these roots determines whether the disturbances grow or decay and the real part of these roots would give the frequency of the modes. The results show a reasonable agreement between the predicted values of dominant frequencies in the present model and those calculated in previous related studies.

Keywords: combustion instability, dominant frequencies, flame speed, premixed combustor

Procedia PDF Downloads 373

Authors: G. Barański, P. Kacejko, M. Wendeker

Abstract:

The impact of the ignition advance control algorithms of the ASz-62IR-16X aircraft piston engine on a combustion process has been presented in this paper. This aircraft engine is a nine-cylinder 1000 hp engine with a special electronic control ignition system. This engine has two spark plugs per cylinder with an ignition advance angle dependent on load and the rotational speed of the crankshaft. Accordingly, in most cases, these angles are not optimal for power generated. The scope of this paper is focused on developing algorithms to control the ignition advance angle in an electronic ignition control system of an engine. For this type of engine, i.e. radial engine, an ignition advance angle should be controlled independently for each cylinder because of the design of such an engine and its crankshaft system. The ignition advance angle is controlled in an open-loop way, which means that the control signal (i.e. ignition advance angle) is determined according to the previously developed maps, i.e. recorded tables of the correlation between the ignition advance angle and engine speed and load. Load can be measured by engine crankshaft speed or intake manifold pressure. Due to a limited memory of a controller, the impact of other independent variables (such as cylinder head temperature or knock) on the ignition advance angle is given as a series of one-dimensional arrays known as corrective characteristics. The value of the ignition advance angle specified combines the value calculated from the primary characteristics and several correction factors calculated from correction characteristics. Individual cylinder control can proceed in line with certain indicators determined from pressure registered in a combustion chamber. Control is assumed to be based on the following indicators: maximum pressure, maximum pressure angle, indicated mean effective pressure. Additionally, a knocking combustion indicator was defined. Individual control can be applied to a single set of spark plugs only, which results from two fundamental ideas behind designing a control system. Independent operation of two ignition control systems – if two control systems operate simultaneously. It is assumed that the entire individual control should be performed for a front spark plug only and a rear spark plug shall be controlled with a fixed (or specific) offset relative to the front one or from a reference map. The developed algorithms will be verified by simulation and engine test sand experiments. This work has been financed by the Polish National Centre for Research and Development, INNOLOT, under Grant Agreement No. INNOLOT/I/1/NCBR/2013.

Keywords: algorithm, combustion process, radial engine, spark plug

Procedia PDF Downloads 287

Authors: Protik Basu, Indranil Ghosh, Pranab K. Dan

Abstract:

Lean management is an integrated socio-technical system to bring about a competitive state in an organization. The purpose of this paper is to explore and integrate the role of customers and suppliers with the internal practices of the Indian manufacturing industries towards successful implementation of lean manufacturing (LM). An extensive literature survey is carried out. An attempt is made to build an exhaustive list of all the input manifests related to customers, suppliers and internal practices necessary for LM implementation, coupled with a similar exhaustive list of the benefits accrued from its successful implementation. A structural model is thus conceptualized, which is empirically validated based on the data from the Indian manufacturing sector. With the current impetus on developing the industrial sector, the Government of India recently introduced the Lean Manufacturing Competitiveness Scheme that aims to increase competitiveness with the help of lean concepts. There is a huge scope to enrich the Indian industries with the lean benefits, the implementation status being quite low. Hardly any survey-based empirical study in India has been found to integrate customers and suppliers with the internal processes towards successful LM implementation. This empirical research is thus carried out in the Indian manufacturing industries. The basic steps of the research methodology followed in this research are the identification of input and output manifest variables and latent constructs, model proposition and hypotheses development, development of survey instrument, sampling and data collection and model validation (exploratory factor analysis, confirmatory factor analysis, and structural equation modeling). The analysis reveals six key input constructs and three output constructs, indicating that these constructs should act in unison to maximize the benefits of implementing lean. The structural model presented in this paper may be treated as a guide to integrating customers and suppliers with internal practices to successfully implement lean. Integrating customers and suppliers with internal practices into a unified, coherent manufacturing system will lead to an optimum utilization of resources. This work is one of the very first researches to have a survey-based empirical analysis of the role of customers, suppliers and internal practices of the Indian manufacturing sector towards an effective lean implementation.

Keywords: customer management, internal manufacturing practices, lean benefits, lean implementation, lean manufacturing, structural model, supplier management

Procedia PDF Downloads 174

Authors: M. Moharami Gargari, S. Javdani Zamani, A. Mohammadnejad, S. Abuali

Abstract:

As maritime container transport is developing fast, the need arises for efficient operations at container terminals. One of the most important determinants of container handling efficiency is the productivity of quay cranes and internal transportation vehicles, which are responsible transporting of containers for unloading and loading operations for container vessels. For this reason, this paper presents an integrated mathematical model formulation for discrete berths with quay cranes and internal transportations vehicles. The problems have received increasing attention in the literature and the present paper deals with the integration of these interrelated problems. A new mixed integer linear formulation is developed for the Berth Allocation Problem (BAP), Quay Crane Assignment and Scheduling Problem (QCASP) and Internal Transportation Scheduling (ITS), which accounts for cranes and trucks positioning conditions.

Keywords: discrete berths, container terminal, truck scheduling, dynamic vessel arrival

Procedia PDF Downloads 392

Authors: C. Malça, P. Gonçalves, N. Alves, A. Mateus

Abstract:

Regardless of the manufacturing process used, subtractive or additive, material, purpose and application, produced components are conventionally solid mass with more or less complex shape depending on the production technology selected. Aspects such as reducing the weight of components, associated with the low volume of material required and the almost non-existent material waste, speed and flexibility of production and, primarily, a high mechanical strength combined with high structural performance, are competitive advantages in any industrial sector, from automotive, molds, aviation, aerospace, construction, pharmaceuticals, medicine and more recently in human tissue engineering. Such features, properties and functionalities are attained in metal components produced using the additive technique of Rapid Prototyping from metal powders commonly known as Selective Laser Melting (SLM), with optimized internal topologies and varying densities. In order to produce components with high strength and high structural and functional performance, regardless of the type of application, three different internal topologies were developed and analyzed using numerical computational tools. The developed topologies were numerically submitted to mechanical compression and four point bending testing. Finite Element Analysis results demonstrate how different internal topologies can contribute to improve mechanical properties, even with a high degree of porosity relatively to fully dense components. Results are very promising not only from the point of view of mechanical resistance, but especially through the achievement of considerable variation in density without loss of structural and functional high performance.

Keywords: additive manufacturing, internal topologies, porosity, rapid prototyping, selective laser melting

Procedia PDF Downloads 326

Authors: Nititorn Ounpipat

Abstract:

The objective of this study was to find the relationship between internal communication and job satisfaction, and to find out the best communication channel to contact employees for a quality working within the operation or organizational rules. The sample size of 100% who were working as a shop floor level employee in the company. The study used the quantitative research method by distributing a structured questionnaire to collect data from 150 employees as the sample size. Inferential statistics and forward multiple regression analysis were used to analyze the results of this research. The result shows that communication channel correlated with job satisfaction. Each channel has a correlation with the satisfaction of working with the Department Board Information and All Employee / Weekly Meeting Relevance high. Since there is a correlation coefficient equal. 851 and. 840, respectively. Company Board Information, Memo, Letter, Leader, Supervisor, Friends and Email Relevance moderate as well.

Keywords: internal communication channels, job satisfaction, personal feedback, Rayong province

Procedia PDF Downloads 220

Authors: G. K. Guseynova, V. V. Krylov, L. T. Khamidova, N. A. Polunina, V. A. Lukyanchikov

Abstract:

The report presents complex ultrasound diagnostics in patients with symptomatic steno-occlusive lesions of extra- and intracranial branches of brachiocephalic arteries (BCA). The tasks and possibilities of ultrasound diagnostics at different stages of treatment of patients with symptomatic occlusion of internal carotid artery (ICA) are covered in detail; qualitative and quantitative characteristics of blood flow; parameters of the wall and lumen of the main arteries of the head; methods of ultrasound examination of indirect assessment of the functional status are presented. Special attention is paid to the description of indicators that are predictors of the consistency of formed extra-intracranial low-flow shunts, examples of functioning and failed anastomoses are analyzed.

Keywords: CBF, cerebral blood flow; CTA, external carotid artery; ICA, internal carotid artery; MCA, middle cerebral artery; MRA, magnetic resonance angiography; OEF, oxygen extraction fraction; TIA, transient ischaemic attack, ultrasound, low-flow bypass, anastomoses

Procedia PDF Downloads 32

Authors: Rui Sun, Tamer M. Ismail, Xiaohan Ren, M. Abd El-Salam

Abstract:

Incineration of municipal solid waste (MSW) is one of the key scopes in the global clean energy strategy. A computational fluid dynamics (CFD) model was established. In order to reveal these features of the combustion process in a fixed porous bed of MSW. Transporting equations and process rate equations of the waste bed were modeled and set up to describe the incineration process, according to the local thermal conditions and waste property characters. Gas phase turbulence was modeled using k-ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The heterogeneous reaction rates were determined using Arrhenius eddy dissipation and the Arrhenius-diffusion reaction rates. The effects of primary air flow rate and temperature in the burning process of simulated MSW are investigated experimentally and numerically. The simulation results in bed are accordant with experimental data well. The model provides detailed information on burning processes in the fixed bed, which is otherwise very difficult to obtain by conventional experimental techniques.

Keywords: computational fluid dynamics (CFD) model, waste incineration, municipal solid waste (MSW), fixed bed, primary air

Procedia PDF Downloads 396

Authors: Prateep Wajeetongratana

Abstract:

The objective of this research is to examine the effects of internal audit innovation on firm performance effectiveness influences of financial report reliability, organizational process improvement, and risk management effectiveness. This paper drew upon the survey data collected from 400 employees survey conducted at Nonthaburi province, Thailand. The statistics utilized in this paper included percentage, mean, standard deviation, and regression analysis. The findings revealed that the majority of samples were between 31-40 years old, married, held an undergraduate degree, and had an average income between 10,000-15,000 baht. And also the results show that auditing integration has only influence on financial report reliability. Moreover, corporate risk evaluation has effect on firm performance by risk management effectiveness and control self-assessment has effect influence on firm performance by organizational process improvement and risk management effectiveness as well.

Keywords: corporate risk evaluation, firm performance effectiveness, internal audit innovation, marketing management

Procedia PDF Downloads 371

Authors: Helena Macedo, Larissa Tomaz, Levi Guimarães, Luís Cerqueira-Pinto, José Dinis-Carvalho

Abstract:

In the context of retail logistics, the pursuit of operational efficiency and cost optimization involves a rigorous distinction between value-added and non-value-added activities. In today's competitive market, optimizing efficiency and reducing operational costs are paramount for retail businesses. This research paper focuses on the development of a classification model adapted to the retail sector, specifically examining internal logistics processes. Based on a comprehensive analysis conducted in a retail supermarket located in the north of Portugal, which covered various aspects of internal retail logistics, this study questions the concept of value and the definition of wastes traditionally applied in a manufacturing context and proposes a new way to assess activities in the context of internal logistics. This study combines quantitative data analysis with qualitative evaluations. The proposed classification model offers a systematic approach to categorize operations within the retail logistics chain, providing actionable insights for decision-makers to streamline processes, enhance productivity, and allocate resources more effectively. This model contributes not only to academic discourse but also serves as a practical tool for retail businesses, aiding in the enhancement of their internal logistics dynamics.

Keywords: lean retail, lean logisitcs, retail logistics, value-added and non-value-added

Procedia PDF Downloads 50