Search results for: energy and emission flow analyze
Commenced in January 2007
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Edition: International
Paper Count: 16761

Search results for: energy and emission flow analyze

3231 Risk Factors and Regional Difference in the Prevalence of Fecal Carriage Third-Generation Cephalosporin-Resistant E. Coli in Taiwan

Authors: Wan-Ling Jiang, Hsin Chi, Jia-Lu Cheng, Ming-Fang Cheng

Abstract:

Background: Investigating the risk factors for the fecal carriage of third-generation cephalosporin-resistant E.coli could contribute to further disease prevention. Previous research on third-generation cephalosporin-resistant prevalence in children in different regions of Taiwan is limited. This project aims to explore the risk factors and regional differences in the prevalence of third-generation cephalosporin-resistant and other antibiotic-resistant E. coli in the northern, southern, and eastern regions of Taiwan. Methods: We collected data from children aged 0 to 18 from community or outpatient clinics from July 2022 to May 2023 in southern, northern, and eastern Taiwan. The questionnaire was designed to survey the characteristics of participants and possible risk factors, such as clinical information, household environment, drinking water, and food habits. After collecting fecal samples and isolating stool culture with E.coli, antibiotic sensitivity tests and MLST typing were performed. Questionnaires were used to analyze the risk factors of third-generation cephalosporin-resistant E. coli in the three different regions of Taiwan. Results: In the total 246 stool samples, third-generation cephalosporin-resistant E.coli accounted for 37.4% (97/246) of all isolates. Among the three different regions of Taiwan, the highest prevalence of fecal carriage with third-generation cephalosporin-resistant E.coli was observed in southern Taiwan (42.7%), followed by northern Taiwan (35.5%) and eastern Taiwan (28.4%). Multi-drug resistant E. coli had prevalence rates of 51.9%, 66.3%, and 37.1% in the northern, southern, and eastern regions, respectively. MLST typing revealed that ST131 was the most prevalent type (11.8%). The prevalence of ST131 in northern, southern, and eastern Taiwan was 10.1%, 12.3%, and 13.2%, respectively. Risk factors analysis identified lower paternal education, overweight status, and non-vegetarian diet as statistical significance risk factors for third-generation cephalosporin-resistant E.coli. Conclusion: The fecal carriage rates of antibiotic-resistant E. coli among Taiwanese children were on the rise. This study found regional disparities in the prevalence of third-generation cephalosporin-resistant and multi-drug-resistant E. coli, with southern Taiwan having the highest prevalence. Lower paternal education, overweight, and non-vegetarian diet were the potential risk factors of third-generation cephalosporin-resistant E. coli in this study.

Keywords: Escherichia coli, fecal carriage, antimicrobial resistance, risk factors, prevalence

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3230 Gas Condensing Unit with Inner Heat Exchanger

Authors: Dagnija Blumberga, Toms Prodanuks, Ivars Veidenbergs, Andra Blumberga

Abstract:

Gas condensing units with inner tubes heat exchangers represent third generation technology and differ from second generation heat and mass transfer units, which are fulfilled by passive filling material layer. The first one improves heat and mass transfer by increasing cooled contact surface of gas and condensate drops and film formed in inner tubes heat exchanger. This paper presents a selection of significant factors which influence the heat and mass transfer. Experimental planning is based on the research and analysis of main three independent variables; velocity of water and gas as well as density of spraying. Empirical mathematical models show that the coefficient of heat transfer is used as dependent parameter which depends on two independent variables; water and gas velocity. Empirical model is proved by the use of experimental data of two independent gas condensing units in Lithuania and Russia. Experimental data are processed by the use of heat transfer criteria-Kirpichov number. Results allow drawing the graphical nomogram for the calculation of heat and mass transfer conditions in the innovative and energy efficient gas cooling unit.

Keywords: gas condensing unit, filling, inner heat exchanger, package, spraying, tunes

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3229 Titanium Dioxide Modified with Glutathione as Potential Drug Carrier with Reduced Toxic Properties

Authors: Olga Długosz, Jolanta Pulit-Prociak, Marcin Banach

Abstract:

The paper presents a process to obtain glutathione-modified titanium oxide nanoparticles. The processes were carried out in a microwave radiation field. The influence of the molar ratio of glutathione to titanium oxide and the effect of the fold of NaOH vs. stoichiometric amount on the size of the formed TiO₂ nanoparticles was determined. The physicochemical properties of the obtained products were evaluated using dynamic light scattering (DLS), transmission electron microscope- energy-dispersive X-ray spectroscopy (TEM-EDS), low-temperature nitrogen adsorption method (BET), X-Ray Diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) microscopy methods. The size of TiO₂ nanoparticles was characterized from 30 to 336 nm. The release of titanium ions from the prepared products was evaluated. These studies were carried out using different media in which the powders were incubated for a specific time. These were water, SBF and Ringer's solution. The release of titanium ions from modified products is weaker compared to unmodified titanium oxide nanoparticles. The reduced release of titanium ions may allow the use of such modified materials as substances in drug delivery systems.

Keywords: titanium dioxide, nanoparticles, drug carrier, glutathione

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3228 Titanium Dioxide Modified with Glutathione as Potential Drug Carrier with Reduced Toxic Properties

Authors: Olga Długosz, Jolanta Pulit-Prociak, Marcin Banach

Abstract:

The paper presents a process to obtain glutathione-modified titanium oxide nanoparticles. The processes were carried out in a microwave radiation field. The influence of the molar ratio of glutathione to titanium oxide and the effect of the fold of NaOH vs. stoichiometric amount on the size of the formed TiO₂ nanoparticles was determined. The physicochemical properties of the obtained products were evaluated using dynamic light scattering (DLS), transmission electron microscope- energy-dispersive X-ray spectroscopy (TEM-EDS), low-temperature nitrogen adsorption method (BET), X-Ray Diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) microscopy methods. The size of TiO₂ nanoparticles was characterized from 30 to 336 nm. The release of titanium ions from the prepared products was evaluated. These studies were carried out using different media in which the powders were incubated for a specific time. These were: water, SBF, and Ringer's solution. The release of titanium ions from modified products is weaker compared to unmodified titanium oxide nanoparticles. The reduced release of titanium ions may allow the use of such modified materials as substances in drug delivery systems.

Keywords: titanium dioxide, nanoparticles, drug carrier, glutathione

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3227 The “Buffer Layer” An Improved Electrode-Electrolyte Interface For Solid-State Batteries

Authors: Gregory Schmidt

Abstract:

Solid-state lithium batteries are broadly accepted as promising candidates for application in the next generation of EVs as they should offer safer and higher-energy-density batteries. Nonetheless, their development is impeded by many challenges, including the resistive electrode–electrolyte interface originating from the removal of the liquid electrolyte that normally permeates through the porous cathode and ensures efficient ionic conductivity through the cell. One way to tackle this challenge is by formulating composite cathodes containing solid ionic conductors in their structure, but this approach will require the conductors to exhibit chemical stability, electrochemical stability, flexibility, and adhesion and is, therefore, limited to some materials. Recently, Arkema developed a technology called buffering layer which allows the transformation of any conventional porous electrode into a catholyte. This organic layer has a very high ionic conductivity at room temperature, is compatible with all active materials, and can be processed with conventional Gigafactory equipment. Moreover, this layer helps protect the solid ionic conductor from the cathode and anode materials. During this presentation, the manufacture and the electrochemical performance of this layer for different systems of cathode and anode will be discussed.

Keywords: electrochemistry, all solid state battery, materials, interface

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3226 Multiple Primary Pulmonary Meningiomas: A Case Report

Authors: Wellemans Isabelle, Remmelink Myriam, Foucart Annick, Rusu Stefan, Compère Christophe

Abstract:

Primary pulmonary meningioma (PPM) is a very rare tumor, and its occurrence has been reported only sporadically. Multiple PPMs are even more exceptional, and herein, we report, to the best of our knowledge, the fourth case, focusing on the clinicopathological features of the tumor. Moreover, the possible relationship between the use of progesterone–only contraceptives and the development of these neoplasms will be discussed. Case Report: We report a case of a 51-year-old female presenting three solid pulmonary nodules, with the following localizations: right upper lobe, middle lobe, and left lower lobe, described as incidental findings on computed tomography (CT) during a pre-bariatric surgery check-up. The patient revealed no drinking or smoking history. The physical exam was unremarkable except for the obesity. The lesions ranged in size between 6 and 24 mm and presented as solid nodules with lobulated contours. The largest lesion situated in the middle lobe had mild fluorodeoxyglucose (FDG) uptake on F-18 FDG positron emission tomography (PET)/CT, highly suggestive of primary lung neoplasm. For pathological assessment, video-assisted thoracoscopic middle lobectomy and wedge resection of the right upper nodule was performed. Histological examination revealed relatively well-circumscribed solid proliferation of bland meningothelial cells growing in whorls and lobular nests, presenting intranuclear pseudo-inclusions and psammoma bodies. No signs of anaplasia were observed. The meningothelial cells expressed diffusely Vimentin, focally Progesterone receptors and were negative for epithelial (cytokeratin (CK) AE1/AE3, CK7, CK20, Epithelial Membrane Antigen (EMA)), neuroendocrine markers (Synaptophysin, Chromogranin, CD56) and Estrogenic receptors. The proliferation labelling index Ki-67 was low (<5%). Metastatic meningioma was ruled out by brain and spine magnetic resonance imaging (MRI) scans. The third lesion localized in the left lower lobe was followed-up and resected three years later because of its slow but significant growth (14 mm to 16 mm), alongside two new infra centimetric lesions. Those three lesions showed a morphological and immunohistochemical profile similar to previously resected lesions. The patient was disease-free one year post-last surgery. Discussion: Although PPMs are mostly benign and slow-growing tumors with an excellent prognosis, they do not present specific radiological characteristics, and it is difficult to differentiate it from other lung tumors, histopathologic examination being essential. Aggressive behavior is associated with atypical or anaplastic features (WHO grades II–III) The etiology is still uncertain and different mechanisms have been proposed. A causal connection between sexual hormones and meningothelial proliferation has long been suspected and few studies examining progesterone only contraception and meningioma risk have all suggested an association. In line with this, our patient was treated with Levonorgestrel, a progesterone agonist, intra-uterine device (IUD). Conclusions: PPM, defined by the typical histological and immunohistochemical features of meningioma in the lungs and the absence of central nervous system lesions, is an extremely rare neoplasm, mainly solitary and associating, and indolent growth. Because of the unspecific radiologic findings, it should always be considered in the differential diagnosis of lung neoplasms. Regarding multiple PPM, only three cases are reported in the literature, and this is the first described in a woman treated by a progesterone-only IUD to the best of our knowledge.

Keywords: pulmonary meningioma, multiple meningioma, meningioma, pulmonary nodules

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3225 Sensorless Machine Parameter-Free Control of Doubly Fed Reluctance Wind Turbine Generator

Authors: Mohammad R. Aghakashkooli, Milutin G. Jovanovic

Abstract:

The brushless doubly-fed reluctance generator (BDFRG) is an emerging, medium-speed alternative to a conventional wound rotor slip-ring doubly-fed induction generator (DFIG) in wind energy conversion systems (WECS). It can provide competitive overall performance and similar low failure rates of a typically 30% rated back-to-back power electronics converter in 2:1 speed ranges but with the following important reliability and cost advantages over DFIG: the maintenance-free operation afforded by its brushless structure, 50% synchronous speed with the same number of rotor poles (allowing the use of a more compact, and more efficient two-stage gearbox instead of a vulnerable three-stage one), and superior grid integration properties including simpler protection for the low voltage ride through compliance of the fractional converter due to the comparatively higher leakage inductances and lower fault currents. Vector controlled pulse-width-modulated converters generally feature a much lower total harmonic distortion relative to hysteresis counterparts with variable switching rates and as such have been a predominant choice for BDFRG (and DFIG) wind turbines. Eliminating a shaft position sensor, which is often required for control implementation in this case, would be desirable to address the associated reliability issues. This fact has largely motivated the recent growing research of sensorless methods and developments of various rotor position and/or speed estimation techniques for this purpose. The main limitation of all the observer-based control approaches for grid-connected wind power applications of the BDFRG reported in the open literature is the requirement for pre-commissioning procedures and prior knowledge of the machine inductances, which are usually difficult to accurately identify by off-line testing. A model reference adaptive system (MRAS) based sensor-less vector control scheme to be presented will overcome this shortcoming. The true machine parameter independence of the proposed field-oriented algorithm, offering robust, inherently decoupled real and reactive power control of the grid-connected winding, is achieved by on-line estimation of the inductance ratio, the underlying rotor angular velocity and position MRAS observer being reliant upon. Such an observer configuration will be more practical to implement and clearly preferable to the existing machine parameter dependent solutions, and especially bearing in mind that with very little modifications it can be adapted for commercial DFIGs with immediately obvious further industrial benefits and prospects of this work. The excellent encoder-less controller performance with maximum power point tracking in the base speed region will be demonstrated by realistic simulation studies using large-scale BDFRG design data and verified by experimental results on a small laboratory prototype of the WECS emulation facility.

Keywords: brushless doubly fed reluctance generator, model reference adaptive system, sensorless vector control, wind energy conversion

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3224 Managing Early Stakeholder Involvement at the Early Stages of a Building Project Life Cycle

Authors: Theophilus O. Odunlami, Hasan Haroglu, Nader Saleh-Matter

Abstract:

The challenges facing the construction industry are often worsened by the compounded nature of projects coupled with the complexity of key stakeholders involved at different stages of the project. Projects are planned to achieve outlined benefits in line with the business case; however, a lack of effective management of key stakeholders can result in unrealistic delivery aspirations, unnecessary re-works, and overruns. The aim of this study is to examine the early stages of a project lifecycle and investigate the stakeholder management and involvement processes and their impact on the successful delivery of the project. The research engaged with conventional construction organisations and project personnel and stakeholders on diverse projects, using a research strategy to analyse existing project case studies, narrative enquiries, interviews, and surveys using a combined qualitative, quantitative, and mixed method of analysis. Research findings have shown that the involvement of stakeholders at different levels during the early stages has pronounced effects on project delivery; it helps to forge synergy and promotes a clear understanding of individual responsibilities, strengths, and weaknesses. This has often fostered a positive sense of productive collaboration right through the early stages of the project. These research findings intend to contribute to the development of a process framework for stakeholder and project team involvement in the early stages of a project. This framework will align with the selection criteria for stakeholders, contractors, and resources, ultimately contributing to the successful completion of projects. The primary question addressed in this study is stakeholder involvement and management of the early stages of a building project life cycle impacts project delivery. Findings showed that early-stage stakeholder involvement and collaboration between project teams and contractors significantly contribute to project success. However, a strong and healthy communication strategy would be required to maintain the flow of value-added ideas among stakeholders at the early stages to benefit the project at the execution stage.

Keywords: early stages, project lifecycle, stakeholders, decision-making strategy, project framework

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3223 Soil with Carbonate Accumulation in Tensift Al Haouz Lowland (Morocco): Characterization, Genesis and the Environmental Significance

Authors: Lahcen Daoudi, Soukaina Elidrissi, Nathalie Fagel

Abstract:

The calcareous accumulations in the surface formations of the soil, are a very widespread phenomenon in the arid and semi-arid regions. Many aspects of physical and chemical evolution of these soils were debated for more than one century. The last two decades have witnessed a remarkable interest in the study of the calcrete. In Morocco, as in most Mediterranean countries, soils with carbonate accumulation cover large areas of the territory. The isohumic subtropical soils and red Mediterranean soils include always a horizon of calcrete accumulation. In the lowland of Tensift Al Haouz located in the central part of Morocco, the arable lands are underlain by indurate pedogenic calcrete of various thicknesses; this constitutes a serious handicap for agricultural development in the region. Our aims in this study is to analyze the characteristics of the crusts developed in this area in order to identify the various facies, their geographic distribution and the factors that played a significant role in the differentiation of these calcareous accumulations. The characterizations were based on various techniques including field observations, X-ray diffraction analysis (XRD) for both raw materials and clay fractions, SEM analysis, Calcimetry and Loss On Ignition (LOI). The analysis of encrusting calcrete in a rich and varied observation field as the region of Tensift Al Haouz enabled us to specify the important types of accumulations: diffuse, nodular and massive encrusting. The shape of encrusting as well as their consistency and hardness is clearly related to the contents of CaCO3 of the profiles. Among these facies, the hardpan which results from a complex succession of processes is certainly the most morphologically advanced form of encrusting. The vertical and lateral distribution of these forms in the Tensift Al Haouz area indicates that they do not appear randomly but seem related to well defined environmental conditions. The differentiation and evolution of encrusting is under the influence of two major factors: 1) the availability of carbonate rich solution which is controlled by the topography, the nature and texture of underlying host rock and the detrital processes; 2) the climate which is responsible for the evaporation and crystallization of carbonate.

Keywords: soil calcrete, characterization, morphology, Tensift Al Haouz, Morocco

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3222 Oro-Facial Manifestations of Acute Myeloid Leukaemia -A Case Report

Authors: Aamna Tufail, Kajal Kotecha, Iordanis Toursounidis, Ravinder Pabla

Abstract:

Introduction/Aims: Acute Myeloid Leukaemia (AML) is a part of leukaemic group of hematopoietic disorders with a varying range of presentations, including oro-facial manifestations. Early recognition and management are essential for favourable outcomes. Materials and Methods: We present our experience, clinical presentation, and clinical photographs of a patient with previously undiagnosed AML who presented with oral symptoms to the emergency department of our hospital. An analysis of clinical characteristics, diagnostic investigations, and management modalities was performed. Results/Statistics: A 58-year-old man presented to A&E reporting an 11-day history of right sided facial swelling, acute TMJ symptoms, and oral discomfort. A dentist ruled out acute dental causes one day post onset of symptoms. Initial assessment was anatomically inconsistent and did not reveal a routine oral or maxillofacial etiology. Detailed clinical examination demonstrated fever, generalised pallor, swelling and erythema of right nasolabial region, bilateral masseteric tenderness, intraoral palatal ecchymosis, palatal ulceration, buccal and labial petechiae, cervical lymphadenopathy, and haematoma on dorsum of right hand overlying right 2nd metacarpal joint. Suspecting a systemic medical cause, we requested haematological investigations, which revealed neutropenia, thrombocytopenia, and anaemia. Flow cytometry confirmed CD34 + AML. Oral discomfort was managed symptomatically. The patient was referred to a tertiary care centre for acute haematologic care, where he was treated with IV antibiotics and continuing cycles of chemotherapy. Conclusions/Clinical Relevance: Oro-facial manifestations may be the first clinical sign of AML. Awareness of its features is vital in early diagnosis. In this context, dentists and oral medicine specialists can play an important role in detecting clinical signs of haematological disorders such as AML.

Keywords: acute myeloid leukaemia, oral symptoms, ulceration, diagnosis, management

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3221 Trends in Endoscopic Versus Open Treatment of Carpal Tunnel Syndrome in Rheumatoid Arthritis Patients

Authors: Arman Kishan, Sanjay Kubsad, Steve Li, Mark Haft, Duc Nguyen, Dawn Laporte

Abstract:

Objective: Carpal tunnel syndrome can be managed surgically with endoscopic or open carpal tunnel release (CTR). Rheumatoid arthritis (RA) is a known risk factor for Carpal Tunnel Syndrome (CTS) and is believed to be related to compression of the median nerve secondary to inflammation. We aimed to analyze national trends, outcomes, and patient-specific comorbidities associated with ECTR and OCTR in patients with RA. Methods: A retrospective cohort study was conducted using the PearlDiver database, identifying 683 RA patients undergoing ECTR and 4234 undergoing OCTR between 2010 and 2014. Demographic data, comorbidities, and complication rates were analyzed. Univariate and multivariable analyses assessed differences between the treatment methods. Results:  Patients with RA undergoing ECTR in comparison to OCTR had no significant differences in medical comorbidities such as hypertension, obesity, chronic kidney disease, hypothyroidism and diabetes mellitus. Patients in the ECTR group reported a risk ratio of 1.44 (95%CI: 1.10-1.89, p=0.01) of requiring repeat procedures within 90 days of the initial procedure. Five-year trends in ECTR and OCTR procedures reported a combined annual growth rate of 5.6% and 13.15, respectively. Conclusion: Endoscopic and open approaches to CTR are important considerations in surgical planning. RA and ECTR have previously been identified as independent risk factors for revision CTR. Our study has identified the 90-day risk of repeat procedures to be elevated in the ECTR group in comparison to the OCTR group. Additionally, the growth of OCTR procedures has outpaced the growth of ECTR procedures in the same period, likely in response to the trend of ECTR leading to higher rates of repeat procedures. The need for revision following ECTR in patients with RA could be related to chronic inflammation leading to transverse carpal ligament thickening and concomitant tenosynovitis. Future directions could include further characterization of repeat procedures performed in this subset of patients. 

Keywords: endoscopic treatment of carpal tunnel syndrome, open treatment of carpal tunnel syndrome, rheumatoid arthritis, trends analysis, carpal tunnel syndrome

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3220 Steady State Rolling and Dynamic Response of a Tire at Low Frequency

Authors: Md Monir Hossain, Anne Staples, Kuya Takami, Tomonari Furukawa

Abstract:

Tire noise has a significant impact on ride quality and vehicle interior comfort, even at low frequency. Reduction of tire noise is especially important due to strict state and federal environmental regulations. The primary sources of tire noise are the low frequency structure-borne noise and the noise that originates from the release of trapped air between the tire tread and road surface during each revolution of the tire. The frequency response of the tire changes at low and high frequency. At low frequency, the tension and bending moment become dominant, while the internal structure and local deformation become dominant at higher frequencies. Here, we analyze tire response in terms of deformation and rolling velocity at low revolution frequency. An Abaqus FEA finite element model is used to calculate the static and dynamic response of a rolling tire under different rolling conditions. The natural frequencies and mode shapes of a deformed tire are calculated with the FEA package where the subspace-based steady state dynamic analysis calculates dynamic response of tire subjected to harmonic excitation. The analysis was conducted on the dynamic response at the road (contact point of tire and road surface) and side nodes of a static and rolling tire when the tire was excited with 200 N vertical load for a frequency ranging from 20 to 200 Hz. The results show that frequency has little effect on tire deformation up to 80 Hz. But between 80 and 200 Hz, the radial and lateral components of displacement of the road and side nodes exhibited significant oscillation. For the static analysis, the fluctuation was sharp and frequent and decreased with frequency. In contrast, the fluctuation was periodic in nature for the dynamic response of the rolling tire. In addition to the dynamic analysis, a steady state rolling analysis was also performed on the tire traveling at ground velocity with a constant angular motion. The purpose of the computation was to demonstrate the effect of rotating motion on deformation and rolling velocity with respect to a fixed Newtonian reference point. The analysis showed a significant variation in deformation and rolling velocity due to centrifugal and Coriolis acceleration with respect to a fixed Newtonian point on ground.

Keywords: natural frequency, rotational motion, steady state rolling, subspace-based steady state dynamic analysis

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3219 Adsorptive Waste Heat Based Air-Conditioning Control Strategy for Automotives

Authors: Indrasen Raghupatruni, Michael Glora, Ralf Diekmann, Thomas Demmer

Abstract:

As the trend in automotive technology is fast moving towards hybridization and electrification to curb emissions as well as to improve the fuel efficiency, air-conditioning systems in passenger cars have not caught up with this trend and still remain as the major energy consumers amongst others. Adsorption based air-conditioning systems, e.g. with silica-gel water pair, which are already in use for residential and commercial applications, are now being considered as a technology leap once proven feasible for the passenger cars. In this paper we discuss a methodology, challenges and feasibility of implementing an adsorption based air-conditioning system in a passenger car utilizing the exhaust waste heat. We also propose an optimized control strategy with interfaces to the engine control unit of the vehicle for operating this system with reasonable efficiency supported by our simulation and validation results in a prototype vehicle, additionally comparing to existing implementations, simulation based as well as experimental. Finally we discuss the influence of start-stop and hybrid systems on the operation strategy of the adsorption air-conditioning system.

Keywords: adsorption air-conditioning, feasibility study, optimized control strategy, prototype vehicle

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3218 Cadmium Filter Cake of a Hydrometallurgical Zinc Smelter as a New Source for the Biological Synthesis of CdS Quantum Dots

Authors: Mehran Bakhshi, Mohammad Raouf Hosseini, Mohammadhosein Rahimi

Abstract:

The cadmium sulfide nanoparticles were synthesized from the nickel-cadmium cake of a hydrometallurgical zinc producing plant and sodium sulfide as Cd2+ and S-2 sources, respectively. Also, the synthesis process was performed by using the secretions of Bacillus licheniformis as bio-surfactant. Initially, in order to obtain a cadmium rich solution, two following steps were carried out: 1) Alkaline leaching for the removal of zinc oxide from the cake, and 2) acidic leaching to dissolve cadmium from the remained solid residue. Afterward, the obtained CdSO4 solution was used for the nanoparticle biosynthesis. Nanoparticles were characterized by the energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) to confirm the formation of CdS crystals with cubic structure. Also, transmission electron microscopy (TEM) was applied to determine the particle sizes which were in 2-10 nm range. Moreover, the presence of the protein containing bio-surfactants was approved by using infrared analysis (FTIR). In addition, the absorbance below 400 nm confirms quantum particles’ size. Finally, it was shown that valuable CdS quantum dots could be obtained from the industrial waste products via environment-friendly biological approaches.

Keywords: biosynthesis, cadmium cake, cadmium sulfide, nanoparticle, zinc smelter

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3217 Rainwater Harvesting and Management of Ground Water (Case Study Weather Modification Project in Iran)

Authors: Samaneh Poormohammadi, Farid Golkar, Vahideh Khatibi Sarabi

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Climate change and consecutive droughts have increased the importance of using rainwater harvesting methods. One of the methods of rainwater harvesting and, in other words, the management of atmospheric water resources is the use of weather modification technologies. Weather modification (also known as weather control) is the act of intentionally manipulating or altering the weather. The most common form of weather modification is cloud seeding, which increases rain or snow, usually for the purpose of increasing the local water supply. Cloud seeding operations in Iran have been married since 1999 in central Iran with the aim of harvesting rainwater and reducing the effects of drought. In this research, we analyze the results of cloud seeding operations in the Simindashtplain in northern Iran. Rainwater harvesting with the help of cloud seeding technology has been evaluated through its effects on surface water and underground water. For this purpose, two different methods have been used to estimate runoff. The first method is the US Soil Conservation Service (SCS) curve number method. Another method, known as the reasoning method, has also been used. In order to determine the infiltration rate of underground water, the balance reports of the comprehensive water plan of the country have been used. In this regard, the study areas located in the target area of each province have been extracted by drawing maps of the influence coefficients of each area in the GIS software. It should be mentioned that the infiltration coefficients were taken from the balance sheet reports of the country's comprehensive water plan. Then, based on the area of each study area, the weighted average of the infiltration coefficient of the study areas located in the target area of each province is considered as the infiltration coefficient of that province. Results show that the amount of water extracted from the rain with the help of cloud seeding projects in Simindasht is as follows: an increase in runoff 63.9 million cubic meters (with SCS equation) or 51.2 million cubic meters (with logical equation) and an increase in ground water resources: 40.5 million cubic meters.

Keywords: rainwater harvesting, ground water, atmospheric water resources, weather modification, cloud seeding

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3216 Comparative Study of Impact Strength and Fracture Morphological of Nano-CaCO3 and Nanoclay Reinforced HDPE Nanocomposites

Authors: Harun Sepet, Necmettin Tarakcioglu

Abstract:

The present study investigated the impact strength and fracture mechanism of nano-CaCO3 and nanoclay reinforced HDPE nanocomposites by using Charpy impact test. The nano-CaCO3 and nanoclay reinforced HDPE granules were prepared by the melt blending method using a compounder system, which consists of industrial banbury mixer, single screw extruder and granule cutting in industrial-scale. The nano-CaCO3 and nanoclay reinforced HDPE granules were molded using an injection-molding machine as plates, and then impact samples were cut by using punching die from the nanocomposite plates. As a result of impact experiments, nano-CaCO3 and nanoclay reinforced HDPE nanocomposites were determined to have lower impact energy level than neat HDPE. Also, the impact strength of HDPE further decreased by addition nanoclay compared to nano-CaCO3. The occurred fracture areas with the impact were detected by SEM examination. It is understood that fracture surface morphology changes when nano-CaCO3 and nanoclay ratio increases. The fracture surface changes were examined to determine the fracture mechanism of nano-CaCO3 and nanoclay reinforced HDPE nanocomposites.

Keywords: charpy, HDPE, industrial scale nano-CaCO3, nanoclay, nanocomposite

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3215 Determinants of Pupils' Performance in the National Achievement Test in Public Elementary Schools of Cavite City

Authors: Florenda B. Cardinoza

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This study was conducted to determine the determinants of Grade III and grade VI pupils’ performance in the National Achievement Test in the Division of Cavite City, School Year 2011-2012. Specifically, the research aimed to: (1) describe the demographic profile of the respondents in terms of age, sex, birth order, family size, family income, and occupation of parents; (2) determine the level of attitude towards NAT; and (3) describe the degree of relationship between the following variables: school support, teachers’ support, and lastly family support for the pupils’ performance in 2012 NAT. The study used the descriptive-correlation research method to investigate the determinants of pupils’ performance in the National Achievement Test of Public Elementary Schools in the Division of Cavite City. The instrument used in data gathering was a self-structured survey. The NAT result for SY 2011-2012 provided by NETRC and DepEd Cavite City was also utilized. The statistical tools used to process and analyze the data were frequency distribution, percentage, mean, standard deviation, Kruskall Wallis, Mann-Whitney, t-test for independent samples, One-way ANOVA, and Spearman Rank Correlational Coefficient. Results revealed that there were more female students than males in the Division of Cavite City; out of 659 respondents, 345 were 11 years old and above; 390 were females; 283 were categorized as first child in the family; 371 of the respondents were from small family; 327 had Php5000 and below family income; 450 of the fathers’ respondents were non professionals; and 431 of the mothers respondents had no occupation. The attitude towards NAT, with a mean of 1.65 and SD of .485, shows that respondents considered NAT important. The school support towards NAT, with a mean of 1.89 and SD of .520, shows that respondents received school support. The pupils had a very high attitude towards teachers’ support in NAT with a mean of 1.60 and SD of .572. Family support, with t-test of 16.201 with a p-value of 0.006, shows significant at 5 percent level. Thus, the determinants of pupils’ performance in NAT in terms of family support for NAT preparation is not significant according to their family income. The grade level, with the t-test is 4.420 and a p-value of 0.000, is significant at 5 percent level. Therefore, the determinants of pupils’ performance in NAT in terms of grade level for NAT preparation vary according to their grade level. For the determinants of pupils’ performance of NAT sample test for attitude towards NAT, school support, teachers’ support, and family support were noted highly significant with a p value of 0.000.

Keywords: achievement, determinants, national, performance, public, pupils', test

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3214 Transforming Space to Place: Best-Practice Approaches and Initiatives

Authors: Juanee Cilliers

Abstract:

Urban citizens have come to expect more from their cities, demanding optimal conditions for business creativity and professional development, along with efficient, sustainable transportation and energy systems that feed robust economic development and healthy job markets. Urban public spaces are an important part of the urban environment, creating the framework for public life and quality thereof. The transformation of space into successful public places are crucial in this regard as planning must safeguard flexibility towards future changes, whilst simultaneously be capable of acting on short-term demands in order to address the complexity of public spaces within urban areas. This research evaluated two case studies of different cities in Belgium which successfully transformed spaces into lively public places. The transformation was illustrated and evaluated by means of visual analyses and space usage analyses of the original and redesigned space, along with the experience and value that the redesign brought to the area. Selected design elements were identified and evaluated based on the role in the transformation process, in an attempt to draw conclusions with regards to theory-practice relevance and to guide the transformation of space to place of (similar) public spaces.

Keywords: space, place, transformation, case studies

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3213 Determination of Bromides, Chlorides and Fluorides in Case of Their Joint Presence in Ion-Conducting Electrolyte

Authors: V. Golubeva, O. Vakhnina, I. Konopkina, N. Gerasimova, N. Taturina, K. Zhogova

Abstract:

To improve chemical current sources, the ion-conducting electrolytes based on Li halides (LiCl-KCl, LiCl-LiBr-KBr, LiCl-LiBr-LiF) are developed. It is necessary to have chemical analytical methods for determination of halides to control the electrolytes technology. The methods of classical analytical chemistry are of interest, as they are characterized by high accuracy. Using these methods is a difficult task because halides have similar chemical properties. The objective of this work is to develop a titrimetric method for determining the content of bromides, chlorides, and fluorides in their joint presence in an ion-conducting electrolyte. In accordance with the developed method of analysis to determine fluorides, electrolyte sample is dissolved in diluted HCl acid; fluorides are titrated by La(NO₃)₃ solution with potentiometric indication of equivalence point, fluoride ion-selective electrode is used as sensor. Chlorides and bromides do not form a hardly soluble compound with La and do not interfere in result of analysis. To determine the bromides, the sample is dissolved in a diluted H₂SO₄ acid. The bromides are oxidized with a solution of KIO₃ to Br₂, which is removed from the reaction zone by boiling. Excess of KIO₃ is titrated by iodometric method. The content of bromides is calculated from the amount of KIO₃ spent on Br₂ oxidation. Chlorides and fluorides are not oxidized by KIO₃ and do not interfere in result of analysis. To determine the chlorides, the sample is dissolved in diluted HNO₃ acid and the total content of chlorides and bromides is determined by method of visual mercurometric titration with diphenylcarbazone indicator. Fluorides do not form a hardly soluble compound with mercury and do not interfere with determination. The content of chlorides is calculated taking into account the content of bromides in the sample of electrolyte. The validation of the developed analytical method was evaluated by analyzing internal reference material with known chlorides, bromides and fluorides content. The analytical method allows to determine chlorides, bromides and fluorides in case of their joint presence in ion-conducting electrolyte within the range and with relative total error (δ): for bromides from 60.0 to 65.0 %, δ = ± 2.1 %; for chlorides from 8.0 to 15.0 %, δ = ± 3.6 %; for fluorides from 5.0 to 8.0%, ± 1.5% . The analytical method allows to analyze electrolytes and mixtures that contain chlorides, bromides, fluorides of alkali metals and their mixtures (K, Na, Li).

Keywords: bromides, chlorides, fluorides, ion-conducting electrolyte

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3212 A CD40 Variant is Associated with Systemic Bone Loss Among Patients with Rheumatoid Arthritis

Authors: Rim Sghiri, Samia Al Shouli, Hana Benhassine, Nejla Elamri, Zahid Shakoor, Foued Slama, Adel Almogren, Hala Zeglaoui, Elyes Bouajina, Ramzi Zemni

Abstract:

Objectives: Little is known about genes predisposing to systemic bone loss (SBL) in rheumatoid arthritis (RA). Therefore, we examined the association between SBL and a variant of CD40 gene, which is known to play a critical role in both immune response and bone homeostasis among patients with RA. Methods: CD40 rs48104850 was genotyped in 176 adult RA patients. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (DXA). Results: Low BMD was observed in 116 (65.9%) patients. Among them, 60 (34.1%) had low femoral neck (FN) Z score, 72 (40.9%) had low total femur (TF) Z score, and 105 (59.6%) had low lumbar spine (LS) Z score. CD40 rs4810485 was found to be associated with reduced TF Z score with the CD40 rs4810485 T allele protecting against reduced TF Z score (OR = 0.40, 95% CI = 0.23-0.68, p = 0.0005). This association was confirmed in the multivariate logistic regression analysis (OR=0.31, 95% CI= 0.16-0.59, p=3.84 x 10₋₄). Moreover, median FN BMD was reduced among RA patients with CD40 rs4810485 GG genotype compared to RA patients harbouring CD40 rs4810485 TT and GT genotypes (0.788± 0.136 versus 0.826± 0.146g/cm², p=0.001). Conclusion: This study, for the first time ever, demonstrated an association between a CD40 genetic variant and SBL among patients with RA.

Keywords: rheumatoid arthritis, CD40 gene, bone mineral density, systemic bone loss, rs48104850

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3211 Utilization of Aluminium Dross as a Main Raw Material for Synthesize the Geopolymers via Mechanochemistry Method

Authors: Pimchanok Puksisuwan, Pitak Laorattanakul, Benya Cherdhirunkorn

Abstract:

The use of aluminium dross as a raw material for geopolymer synthesis via mechanochemistry method was studied. The geopolymers were prepared using aluminium dross from secondary aluminium industry, fly ash from a biomass power plant and liquid alkaline activators, which is a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH) (Na2SiO3/NaOH ratio 4:1, 3:1 and 2:1). Aluminium dross consists mostly of alumina (Al2O3), silicon oxide (SiO2) and aluminium nitride (AlN). The raw materials were mixed and milled using the high energy ball milling method for 5, 10 and 15 minutes in order to reduce the particle size. The milled powders were uniaxially pressed into a cylinder die with the pressure of 2200 psi. The cylinder samples were cured in the sealed plastic bags for 3, 7 and 14 days at the room temperature and 60°C for 24 hour. The mechanical property of geopolymers was investigated. In addition, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were carried out in order to study the microstructure and phase structures of the geopolymers, respectively. The results showed that aluminium dross could enhance the mechanical property of geopolymers product by mechanochemistry method and meet the TISI requirements.

Keywords: aluminium dross, fly ash, geopolymer, mechanochemistry

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3210 A Study of Female Casino Dealers' Job Stress and Job Satisfaction: The Case of Macau

Authors: Xinrong Zong, Tao Zhang

Abstract:

Macau is known as the Oriental Monte Carlo and its economy depends on gambling heavily. The dealer is the key position of the gambling industry, at the end of the fourth quarter of 2015, there were over 24,000 dealers among the 56,000 full-time employees in gambling industry. More than half of dealers were female. The dealer is also called 'Croupier', the main responsibilities of them are shuffling, dealing, processing chips, rolling dice game and inspecting play. Due to the limited land and small population of Macao, the government has not allowed hiring foreign domestic dealers since Macao developed temporary gambling industry. Therefore, local dealers enjoy special advantages but also bear the high stresses from work. From the middle of last year, with the reduced income of gambling, and the decline of mainland gamblers as well as VIP lounges, the working time of dealers increased greatly. Thus, many problems occurred in this condition, such as the rise of working pressures, psychological pressures and family-responsibility pressures, which may affect job satisfaction as well. Because of the less research of dealer satisfaction, and a lack of standing on feminine perspective to analyze female dealers, this study will focus on investigating the relationship between working pressure and job satisfaction from feminine view. Several issues will be discussed specifically: firstly, to understand current situation of the working pressures and job satisfactions of female dealers in different ages; secondly, to research if there is any relevance between working pressures and job satisfactions of female dealers in different ages; thirdly, to find out the relationship between dealers' working pressures and job satisfactions in different ages. This paper combined qualitative approach with quantitative approach selected samples by convenient sampling. The research showed the female dealers from diverse ages have different kinds of working pressures; second, job satisfactions of the female dealers in different ages are dissimilar; moreover, there is negative correlation between working pressure and job satisfaction of female dealer in different ages' groups; last but not the least, working pressure has a significant negative impact on job satisfaction. The research result will provide a reference value for the Macau gambling business. It is a pattern to improve dealers' working environment, to increase employees' job satisfaction, as well as to offer tourists a better service, which can help to attract more and more visitors from a good image of Macau gaming and tourism.

Keywords: female dealers, job satisfaction, working pressure, Macau

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3209 Advances in Membrane Technologies for Wastewater Treatment

Authors: Deniz Sahin

Abstract:

This study provides a literature review of the special issue on wastewater treatment technologies, especially membrane technologies. Currently, wastewater is a serious and increasing worldwide problem with an adverse effect on the environment and living organisms. For this reason, many technologies have been developed to treat wastewater before discharging it to water bodies. We have been discussed membrane technologies to remove contaminants from wastewater such as heavy metals, dyes, pesticides, etc., which represent the main pollutants in wastewater. All the properties of these technologies including performance, economics, simplicity, and operability are also compared with other wastewater treatment technologies. The conventional water treatment technologies have the disadvantages of low separation efficiency, high energy consumption, and strict operating temperature. To overcome these difficulties, membrane technologies have been developed and used in wastewater treatment. Membrane technology uses a selectively permeable membrane to remove suspended and dissolved solids from water. This membrane is a very thin film of synthetic organic or inorganic materials, that can allow a very selective separation between a mixture and its components. Examples of membrane technologies include microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), electrodialysis (ED), gas separation, etc. Most of these technologies have been used extensively for the treatment of heavy metal wastewater. For instance, wastewater that contains Cu²⁺, Cd²⁺, Pb²⁺, Zn²⁺ was treated by ultrafiltration technology. It was shown that complete removal of metal ions could be achieved.

Keywords: industrial pollution, membrane technologies, metal ions, wastewater

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3208 Recovery of Hydrogen Converter Efficiency Affected by Poisoning of Catalyst with Increasing of Temperature

Authors: Enayat Enayati, Reza Behtash

Abstract:

The purpose of the H2 removal system is to reduce a content of hydrogen and other combustibles in the CO2 feed owing to avoid developing a possible explosive condition in the synthesis. In order to reduce the possibility of forming an explosive gas mixture in the synthesis as much as possible, the hydrogen percent in the fresh CO2, will be removed in hydrogen converter. Therefore the partly compressed CO2/Air mixture is led through Hydrogen converter (Reactor) where the H2, present in the CO2, is reduced by catalytic combustion to values less than 50 ppm (vol). According the following exothermic chemical reaction: 2H2 + O2 → 2H2O + Heat. The catalyst in hydrogen converter consist of platinum on a aluminum oxide carrier. Low catalyst activity maybe due to catalyst poisoning. This will result in an increase of the hydrogen content in the CO2 to the synthesis. It is advised to shut down the plant when the outlet of hydrogen converter increased above 100 ppm, to prevent undesirable gas composition in the plant. Replacement of catalyst will be time exhausting and costly so as to prevent this, we increase the inlet temperature of hydrogen converter according to following Arrhenius' equation: K=K0e (-E_a/RT) K is rate constant of a chemical reaction where K0 is the pre-exponential factor, E_a is the activation energy, and R is the universal gas constant. Increment of inlet temperature of hydrogen converter caused to increase the rate constant of chemical reaction and so declining the amount of hydrogen from 125 ppm to 70 ppm.

Keywords: catalyst, converter, poisoning, temperature

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3207 First Principls Study of Structural, Electronic, Magnetic and Optical Properties of SiNi₂O₄ Spinel Oxide

Authors: Karkour Selma

Abstract:

We conducted first principles full potential calculations using the Wien2k code to explore the structural, electronic, magnetic, and optical properties of SiNi₂O₄, a cubic normal spinel oxide. Our calculations, based on the GGA-PBEsol of the generalized gradient approximation, revealed several key findings. The spinel oxides exhibited a stable cubic structure in the ferromagnetic phase and showed 100% spin polarization. We determined the equilibrium lattice constant and internal parameter values. In terms of the electronic properties, we observed a direct bandgap of 2.68 eV for the spin-up configuration, while the spin-down configuration exhibited an indirect bandgap of 0.82 eV. Additionally, we calculated the total density of states and partial densities for each atom, finding a magnetic moment spin density of states of 8.0 μB per formula unit. The optical properties have been calculated. The real, Ԑ₁(ω) and the imaginary, Ԑ₂(ω) parts of the complex dielectric constants, refractivity, reflection and energy loss when light scattered from the material. The absorption region spanned from 1.5 eV to 14 eV, with significant intensity. The calculated results confirm the suitability of this material for optical and spintronic devices application.

Keywords: DFT, spintronic, GGA, spinel

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3206 Electrode Performance of Carbon Coated Nanograined LiFePO4 in Lithium Batteries

Authors: Princess Stephanie P. Llanos, Rinlee Butch M. Cervera

Abstract:

Lithium iron phosphate (LiFePO4) is a potential cathode material for lithium-ion batteries due to its promising characteristics. In this study, carbon-coated nanograined LiFePO4 is synthesized via wet chemistry method at a low temperature of 400 °C and investigated its performance as a cathode in Lithium battery. The X-ray diffraction pattern of the synthesized samples can be indexed to an orthorhombic LiFePO4 structure. Agglomerated particles that range from 200 nm to 300 nm are observed from scanning electron microscopy images. Transmission electron microscopy images confirm the crystalline structure of LiFePO4 and coating of amorphous carbon layer. Elemental mapping using Energy dispersive spectroscopy analysis revealed the homogeneous dispersion of Fe, P, O, and C elements. On the other hand, the electrochemical performances of the synthesized cathodes were investigated using cyclic voltammetry, galvanostatic charge/discharge tests with different C-rates, and cycling performances. Galvanostatic charge and discharge measurements revealed that the sample sintered at 400 °C for 3 hours with carbon coating demonstrated the highest capacity among the samples which reaches up to 160 mAhg⁻¹ at 0.1C rate.

Keywords: cathode, charge-discharge, electrochemical, lithium batteries

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3205 Development of High Temperature Mo-Si-B Based In-situ Composites

Authors: Erhan Ayas, Buse Katipoğlu, Eda Metin, Rifat Yılmaz

Abstract:

The search for new materials has begun to be used even higher than the service temperature (~1150ᵒC) where nickel-based superalloys are currently used. This search should also meet the increasing demands for energy efficiency improvements. The materials studied for aerospace applications are expected to have good oxidation resistance. Mo-Si-B alloys, which have higher operating temperatures than nickel-based superalloys, are candidates for ultra-high temperature materials used in gas turbine and jet engines. Because the Moss and Mo₅SiB₂ (T2) phases exhibit high melting temperature, excellent high-temperature creep strength and oxidation resistance properties, however, low fracture toughness value at room temperature is a disadvantage for these materials, but this feature can be improved with optimum Moss phase and microstructure control. High-density value is also a problem for structural parts. For example, in turbine rotors, the higher the weight, the higher the centrifugal force, which reduces the creep life of the material. The density value of the nickel-based superalloys and the T2 phase, which is the Mo-Si-B alloy phase, is in the range of 8.6 - 9.2 g/cm³. But under these conditions, T2 phase Moss (density value 10.2 g/cm³), this value is above the density value of nickel-based superalloys. So, with some ceramic-based contributions, this value is enhanced by optimum values.

Keywords: molybdenum, composites, in-situ, mmc

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3204 Image-Based UAV Vertical Distance and Velocity Estimation Algorithm during the Vertical Landing Phase Using Low-Resolution Images

Authors: Seyed-Yaser Nabavi-Chashmi, Davood Asadi, Karim Ahmadi, Eren Demir

Abstract:

The landing phase of a UAV is very critical as there are many uncertainties in this phase, which can easily entail a hard landing or even a crash. In this paper, the estimation of relative distance and velocity to the ground, as one of the most important processes during the landing phase, is studied. Using accurate measurement sensors as an alternative approach can be very expensive for sensors like LIDAR, or with a limited operational range, for sensors like ultrasonic sensors. Additionally, absolute positioning systems like GPS or IMU cannot provide distance to the ground independently. The focus of this paper is to determine whether we can measure the relative distance and velocity of UAV and ground in the landing phase using just low-resolution images taken by a monocular camera. The Lucas-Konda feature detection technique is employed to extract the most suitable feature in a series of images taken during the UAV landing. Two different approaches based on Extended Kalman Filters (EKF) have been proposed, and their performance in estimation of the relative distance and velocity are compared. The first approach uses the kinematics of the UAV as the process and the calculated optical flow as the measurement; On the other hand, the second approach uses the feature’s projection on the camera plane (pixel position) as the measurement while employing both the kinematics of the UAV and the dynamics of variation of projected point as the process to estimate both relative distance and relative velocity. To verify the results, a sequence of low-quality images taken by a camera that is moving on a specifically developed testbed has been used to compare the performance of the proposed algorithm. The case studies show that the quality of images results in considerable noise, which reduces the performance of the first approach. On the other hand, using the projected feature position is much less sensitive to the noise and estimates the distance and velocity with relatively high accuracy. This approach also can be used to predict the future projected feature position, which can drastically decrease the computational workload, as an important criterion for real-time applications.

Keywords: altitude estimation, drone, image processing, trajectory planning

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3203 The Grade Six Pupils' Learning Styles and Their Achievements and Difficulties on Fractions Based on Kolb's Model

Authors: Faiza Abdul Latip

Abstract:

One of the ultimate goals of any nation is to produce competitive manpower and this includes Philippines. Inclination in the field of Mathematics has a significant role in achieving this goal. However, Mathematics, as considered by most people, is the most difficult subject matter along with its topics to learn. This could be manifested from the low performance of students in national and international assessments. Educators have been widely using learning style models in identifying the way students learn. Moreover, it could be the frontline in knowing the difficulties held by each learner in a particular topic specifically concepts pertaining to fractions. However, as what many educators observed, students show difficulties in doing mathematical tasks and in great degree in dealing with fractions most specifically in the district of Datu Odin Sinsuat, Maguindanao. This study focused on the Datu Odin Sinsuat district grade six pupils’ learning styles along with their achievements and difficulties in learning concepts on fractions. Five hundred thirty-two pupils from ten different public elementary schools of the Datu Odin Sinsuat districts were purposively used as the respondents of the study. A descriptive research using the survey method was employed in this study. Quantitative analysis on the pupils’ learning styles on the Kolb’s Learning Style Inventory (KLSI) and scores on the mathematics diagnostic test on fraction concepts were made using this method. The simple frequency and percentage counts were used to analyze the pupils’ learning styles and their achievements on fractions. To determine the pupils’ difficulties in fractions, the index of difficulty on every item was determined. Lastly, the Kruskal-Wallis Test was used in determining the significant difference in the pupils’ achievements on fractions classified by their learning styles. This test was set at 0.05 level of significance. The minimum H-Value of 7.82 was used to determine the significance of the test. The results revealed that the pupils of Datu Odin Sinsuat districts learn fractions in varied ways as they are of different learning styles. However, their achievements in fractions are low regardless of their learning styles. Difficulties in learning fractions were found most in the area of Estimation, Comparing/Ordering, and Division Interpretation of Fractions. Most of the pupils find it very difficult to use fraction as a measure, compare or arrange series of fractions and use the concept of fraction as a quotient.

Keywords: difficulties in fraction, fraction, Kolb's model, learning styles

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3202 Study of a Complete Free Route Implementation in the European Airspace

Authors: Cesar A. Nava-Gaxiola, C. Barrado

Abstract:

Harmonized with SESAR (Single European Sky Research) initiatives, a new concept related with airspace structures have been introduced in Europe, the Free Route Airspace. The key of free route is based in an airspace where users may freely plan a route between a defined entry and exit waypoint, with the possibility of routing via intermediate points, the free route flights remain subject to air traffic control (ATC) for the established separations. Free route airspace does not present anymore fixed airways to airspace users, as a consequence it brings a new paradigm for managing safe separations of aircrafts inside these airspace blocks . Nowadays, several European nations have been introduced the concept, some of them in a complete or partial stage, but finally offering limited benefits to airspace users for this condition. This research evaluates the future scenario of free route implementation across Europe, considering a unique airspace block configuration with a complete upper airspace with free route. The paper is centered in investigating the benefits for airspace users, and the study of possible increments of Air Traffic Controllers task loads with a full application. In this research, fast time simulations are carrying out for discovering how much flight time and distance aircrafts can save with an overall free route establishment. In the other side, the paper explains the evolution of conflicts derivate from possible separation losses between aircrafts in this new environment. Free route conflicts can emerges in any points of the airspace, requiring a great effort for solving it, in comparison with fixed airways, where conflicts normally were found by controllers in known waypoints, and they solved using the fixed network as reference. The airspace configuration modelled in this study take into account the actual navigation waypoints structure, moving into a future scenario, where new ones waypoints are added and new traffic flow patterns appears. In this sense, this research explores the advantages and unknown difficulties that a large scale application of free route concept can carry out in the European airspace.

Keywords: ATC conflicts, efficiency, free route airspace, SESAR

Procedia PDF Downloads 181