Search results for: clean room

Authors: A. Kaddour, S. M. A. Bekkouche

Abstract:

Limiting heat losses during ventilation of indoor building spaces has become a basic aim for architects. Much experience has been gained in terms of ventilation of indoor spaces. Nevertheless, due to the complex applications, attempts to create a theoretical base for solving the problems related to the issue are limited, especially determining the minimum ventilation period required within a designated space. In this paper we have approached this matter, both theoretically and computationally. The conclusion we reached was that controlled ventilation of spaces through vent holes that successively open and close at regular time intervals can limit the excessive circulation of air masses, which in turn limits heat losses. Air change rates through open and tilted windows in rooms of residential buildings driven by atmospheric motions are investigated to evaluate natural ventilation concepts. Model of thermal building simulations is used. A separated sample storey and a sample single room in larger scales were used to measure air transport through window openings under the influence of the external pressure distribution.

Keywords: natural ventilation, temperature factor, air change rates, air circulation

Procedia PDF Downloads 436

Authors: Majed Ahmadi

Abstract:

In recent years, the high penetration of different types of renewable energy sources (RESs) has affected most of the available strategies. The main motivations behind the high penetration of RESs are clean energy, modular system and easy installation. Among different types of RESs, wind turbine (WT) is an interesting choice referring to the availability of wind in almost any area. The new technologies of WT can provide energy from residential applications to wide grid connected applications. Regarding the WT, advantages such as reducing the dependence on fossil fuels and enhancing the independence and flexibility of large power grid are the most prominent. Nevertheless, the high volatile nature of wind speed injects much uncertainty in the grid that if not managed optimally can put the analyses far from the reality.the aim of this project is scrutiny and to offer proper ways for renewing distribution networks with envisage the effects of wind power plants and uncertainties related to distribution systems including wind power generating plants output rate and consumers consuming rate and also decrease the incidents of the whole network losses, amount of pollution, voltage refraction and cost extent.to solve this problem we use dual point estimate method.And algorithm used in this paper is reformed bat algorithm, which will be under exact research furthermore the results.

Keywords: order renewal, wind turbines, bat algorithm, outspread production, uncertainty

Procedia PDF Downloads 270

Authors: Joseph G. Grzywacz, Azza O. Abdelmoneium, Abdallah M. Badahdah

Abstract:

Qatar provides an interesting context for studying family-friendly policies for working adults because it is governed by monarchy and Sharia law provides the foundation for legislation. This study considers gender variation in the perceived importance of and satisfaction with 12 family-friendly benefits (e.g., paid parental leave, flexible work hours, onsite childcare). Data were from a 2017 national sample of native Qatari adults. The perceived importance of family-friendly benefits was comparable for women and men for 7 of 12 benefits. Men rated paid paternity leave higher than women, but women rated telecommuting, dedicated breastfeeding room, onsite childcare, and opportunities to job share higher than men. Women and men reported similar experiences for 9 of 12 family-friendly benefits, but men’s expectations were better met than women’s for flexible work arrangements, telecommuting, and financial support for athletic clubs.

Keywords: culture, family-friendly benefits, gender, work-family

Procedia PDF Downloads 211

Authors: Dler Abdullah Ahmed, Zozan Ahmed Mohammed

Abstract:

Wear as an unavoidable phenomenon in stainless steel contact sliding parts is investigated In this work. Two grades of austenitic AISI 304, and S31254, as well as duplexes of S32205, and AISI 2507, were chosen to compare their wear behavior in temperatures ranging from room temperature to 550°C. The experimental results show that AISI 304 austenitic and AISI 2205 duplex stainless steel had lower wear resistance compared with S31254 and AISI 2507 in various temperatures. When the temperature rose to 140°C, and the wear rate of all grades increased, AISI 304 had the highest at 7.028x10-4 mm3/Nm, and AISI 2507 had the lowest at 4.9033 x 10-4 mm3/Nm. At 300°C, the oxides began to form on the worn surfaces, causing the wear rate to slow. As a result, when temperatures exceeded 300°C, the specific wear rate decreased significantly in all specimens. According to the XRD patterns, the main types of oxides formed on worn surfaces were magnetite, hematite, and chromite.

Keywords: wear, stainless steel, temperature, groove, oxide

Procedia PDF Downloads 54

Authors: Dler Abdullah Ahmed, Zozan Ahmed Mohammed

Abstract:

Wear as an unavoidable phenomenon in stainless steel contact sliding parts is investigated In this work. Two grades of austenitic AISI 304, and S31254, as well as duplexes of S32205, and AISI 2507, were chosen to compare their wear behavior in temperatures ranging from room temperature to 550°C. The experimental results show that AISI 304 austenitic and AISI 2205 duplex stainless steel had lower wear resistance compared with S31254 and AISI 2507 in various temperatures. When the temperature rose to 140°C, and the wear rate of all grades increased, AISI 304 had the highest at 7.028x10-4 mm3/Nm, and AISI 2507 had the lowest at 4.9033 x 10-4 mm3/Nm. At 300°C, the oxides began to form on the worn surfaces, causing the wear rate to slow. As a result, when temperatures exceeded 300°C, the specific wear rate decreased significantly in all specimens. According to the XRD patterns, the main types of oxides formed on worn surfaces were magnetite, hematite, and chromite.

Keywords: wear, stainless steel, temperature, groove, oxide

Procedia PDF Downloads 50

Authors: Simrjit Singh, Neeraj Khare

Abstract:

In recent years, photo-electrochemical (PEC) water splitting with an aim to generate hydrogen (H₂) as a clean and renewable fuel has been the subject of intense research interests. Ferroelectric semiconductors have been demonstrated to exhibit enhanced PEC properties as these can be polarized with the application of an external electric field resulting in a built-in potential which helps in separating out the photogenerated charge carriers. In addition to this, by changing the polarization direction, the energy band alignment at the electrode/electrolyte interface can be modulated in a way that it can help in the easy transfer of the charge carriers from the electrode to the electrolyte. In this paper, we investigated the photoelectrochemical properties of ferroelectric PVDF/Cu/PVDF-NaNbO₃ PEC cell and demonstrated that PEC properties can be tuned with ferroelectric polarization and piezophototronic effect. Photocurrent density is enhanced from ~0.71 mA/cm² to 1.97 mA/cm² by changing the polarization direction. Furthermore, due to flexibility and piezoelectric properties of PVDF/Cu/PVDF-NaNbO₃ PEC cell, a further ~26% enhancement in the photocurrent is obtained using the piezophototronic effect. A model depicting the modulation of band alignment between PVDF and NaNbO₃ with the electric field is proposed to explain the observed tuning of the PEC properties. Electrochemical Impedance spectroscopy measurements support the validity of the proposed model.

Keywords: electrical tuning, H₂ generation, photoelectrochemical, NaNbO₃

Procedia PDF Downloads 163

Authors: Sajjad Sedaghat

Abstract:

In this work, facile and green biosynthesis and characterization of silver–montmorillonite (MMT) nanocomposite is reported at room temperature. Silver nanoparticles (Ag–NPs) were synthesized into the interlamellar space of (MMT) by using water extract of Satureja hortensis L as reducing agent. The MMT was suspended in the aqueous AgNO₃ solution, and after the absorption of silver ions, Ag⁺ was reduced using water extract of Satureja hortensis L to Ag°. Evaluation of the antibacterial properties are also reported. The nanocomposite was characterized by ultraviolet-visible spectroscopy (UV–Vis), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). TEM study showed the formation of nanocomposite using water extract of Satureja hortensis L in the 4.88 – 26.70 nm range and average particles size were 15.79 nm also the XRD study showed that the particles have a face-centered cubic (fcc) structure. The nanocomposite showed the antibacterial properties against Gram-positive and Gram-negative bacteria.

Keywords: antibacterial effects, montmorillonite, Satureja hortensis l, transmission electron microscopy, nanocomposite

Procedia PDF Downloads 150

Authors: Luisito L. Lacatan, Zacha Valerie G. Ancheta, Michelangelo A. Dorado, Lester Joseph M. Ochoa, Anthony Mark G. Tayabas

Abstract:

Ignition Interlock Device or IID is a mechanism installed inside a vehicle which requires the driver to breathe into the device before starting the vehicle. If the IID detects that the alcohol level or blood alcohol content (BAC) is higher than the accepted value, the engine will not start. If the driver is not able to provide a clean breath sample, the IID will log the event, warn the driver, and then start up an alarm. The purpose of the IID is to prevent accidents due to driving under the influence (DUI). With the rise of the two-wheeled vehicle in the Philippines due to its mobility and purchasing power, IIDs are still mainly installed on four-wheeled vehicles. Even though riding the motorcycle when drunk is more dangerous, there are only a small number of installed devices on motorcycles and scooters. The general objective of this study was to develop a system with hardware and software components that would implement IID on motorcycles. The study employed a descriptive method of research. The study also concluded the following: the infrared must have a point-to-point communication, the breathalyzer on the helmet should react to ethanol, the microcontroller on the motorcycle should accept all IR signals from the helmet and interpret it and the GPS shield should have an unobstructed line-of-sight communication with the GPS satellites.

Keywords: blood alcohol content, breathalyser, driving under the influence, global positioning system, global system for mobile communication

Procedia PDF Downloads 309

Authors: Shalluf Milad

Abstract:

Tomatoes are widely produced and consumed due to their nutritional content and versatility. However, the tomato is a soft fruit liable to damage and flavour deterioration. Hence, the main challenge for the tomato producing industry is to prevent the high loss incurred during harvest, handling and transportation of the crops. The objective of this study was to investigate the overall nutritional implication of controlled storage of tomatoes using ozone on the basic nutritional components of tomatoes. This investigation was also designed to focus on the effect of different ozone doses on the basic components (antioxidant activity). Green, yellow and red stages of ripeness (elegance tomatoes), were harvested at different dates for each experiment. The tomatoes were cleaned and placed inside the glass reactors and ozonated at 0.25, 0.50 and 1 mg O3/g tomatoes and clean air respectively for 5 days at 15°C ± 2 and 90-95 % relative humidity respectively. The fruits were analysed for total antioxidant activity. Analysis of the fruits clearly showed that antioxidant activity in the pericarp tissue was the lowest (P<0.001) compared with the pulp tissue of tomatoes during storage in the red stage of maturity, after being treated with ozone in the atmosphere of storage in a dose of 1.00 mgO3/g tomatoes. It can be concluded from this study that the use of ozone in the atmospheres of storage and handling of fresh products maintains the important compounds of these products while maintaining the nutritional value and health quality.

Keywords: post-harvest treatment, controlled atmosphere storage, ozone, tomatoes, antioxidant activity

Procedia PDF Downloads 313

Authors: Sunita Makchuchit, Arunporn Itharat

Abstract:

Prasaprohyai, a Thai traditional medicine preparation listed in the Thai National List of Essential Medicines, is commonly used for treatment of fever and colds. Prasaprohyai preparation consists of 21 different plants, with Kaempferia galanga (50% w/w) as the main ingredient. The objective of this study was to investigate the anti-allergic activity of the crude extract from Prasaprohyai after accelerated stability test procedure. The method of extract used maceration in 95% ethanol and the crude extract was kept under accelerated condition at 40 ± 2 oC and 75 ± 5% relative humidity (RH) for six months. After six months of storage at 40 oC, the crude sample in various storage times (0, 15, 30, 45, 60, 90, 120, 150 and 180 days) were investigated for anti-allergic activity using IgE-sensitized RBL-2H3 cell lines. The results showed that the stability of crude ethanolic extract from Prasaprohyai under accelerated testing had no significant effect of anti-allergic activity when compared with day 0. The results showed that the ethanolic extract could be stored for two years at room temperature without loss of activity.

Keywords: accelerated stability, anti-allergy, prasaprohyai, RBL-2H3 cell lines

Procedia PDF Downloads 471

Authors: Navneet Dabra, Baljinder Kaur, Lakhbir Singh, V. Annapu Reddy, R. Nath, Dae-Yong Jeong, Jasbir S. Hundal

Abstract:

The ferroelectric properties of fused potassium nitrate (KNO3)- polyvinyl alcohol (PVA) composite films have been investigated. The composite films of KNO3-PVA have been prepared by solvant cast technique and then fused over the brass substrate. The ferroelectric hysteresis loops (P-E) have been obtained at room temperature using modified Sawyer-Tower circuit. Percentage of back switching and differential dielectric constant has been derived from P-V loops. The x-ray diffraction (XRD) studies confirm the formation of ferroelectric phase (phase III) in these composite films. The AFM and FE-SEM studies have been used to study the surface morphology of these composite films. The values of remanemt polarization, coercive field, back switching, crystallite size, lattice parameters, and surface roughness have been estimated and correlated.

Keywords: ferroelectric polymer composite, remanemt polarization, back switching, crystallite size, lattice parameters and surface roughness

Procedia PDF Downloads 384

Authors: Rizwan Sultan, Hasnain Zafar

Abstract:

Trauma is the leading cause of death among young population not only in USA but Pakistan as well. The high prevalence of disease should result in larger amount of data and larger number of publications resulting in exploring room for improvement in the field. We aimed to review trauma literature generated from Pakistan in journals indexed with PubMed from January 2010 to December 2014. Search using term “Trauma AND Pakistan” filtering for relevant dates and species human was done on Pubmed. The abstracts and articles were reviewed by the authors to collect data on a preformed performa. 114 articles were published from Pakistan during these 5 years. 64% articles were published in international journals. 63% articles were published in journals with impact factor less than 1. 54% articles were published from one of the four provinces of Pakistan. 64% of articles provided level 4 while 14% articles provided level 5 evidence on the topic. 55% articles discussed epidemiology in non-representative populations. Trauma literature from Pakistan is not only lacking significantly but is also of poor quality and is unable to offer conclusions on this particular subject. There is a lot of space for improvement in the upcoming years.

Keywords: trauma, literature, Pakistan, level of evidence

Procedia PDF Downloads 318

Authors: Nattanon Peerapen, Wanwisa Insang, Lanlalin Khumman, Wipada Juanprajak, Sikan Na Chiangmai, Wacharin Suksanan, Thanasak Tantinakom

Abstract:

This research was intended to study guidelines from elderly care businesses that are continuously growing and rapidly benefitting because these businesses respond to the needs of those who cannot find time to in take care of their elderly people, including intimate care services from the caregivers, thus rapidly expanding elderly care businesses to have recently become interesting domestically and internationally. Chiang Mai is a popular choice for the businesses because of excellent weathers and simple and peaceful ways of living, thus making the businesses grow rapidly and continuously. The sample group consisted of 5 persons, executives and staff, from each of the 4 businesses that provide elderly cares chosen to interview by the researches, which were Vivo Bene Village, Baan Donsuk, PT Nursing Home, and PD Nursing Home. The interviews indicated that most elderly care businesses are located in rural areas with moving traffics, shady environments, and far from crowded urban areas since elderly people need peacefulness and clean environments that will affect their physical and mental health directly. The sections within the businesses are distinctly divided with definite duties assigned to each personnel, including welfares, remunerations, uniforms, accommodations, food and social occasions, such as birthdays or New Year festivities.

Keywords: elderly, elderly care, business strategy, success factors

Procedia PDF Downloads 358

Authors: Anita Yaghobi, Homayoun Ebrahimian

Abstract:

One of the important tools that can help orthopedic doctors for diagnose diseases is imaging scan. Imaging techniques can help physicians in see different parts of the body, including the bones, muscles, tendons, nerves, and cartilage. During CT scan, a patient must be in the same position from the start to the end of radiation treatment. Patient movements are usually monitored by the technologists through the closed circuit television (CCTV) during scan. If the patient makes a small movement, it is difficult to be noticed by them. In the present work, a simple patient movement monitoring device is fabricated to monitor the patient movement. It uses an electronic sensing device. It continuously monitors the patient’s position while the CT scan is in process. The device has been retrospectively tested on 51 patients whose movement and distance were measured. The results show that 25 patients moved 1 cm to 2.5 cm from their initial position during the CT scan. Hence, the device can potentially be used to control and monitor patient movement during CT scan and Radiography. In addition, an audible alarm situated at the control panel of the control room is provided with this device to alert the technologists. It is an inexpensive, compact device which can be used in any CT scan machine.

Keywords: CT scan, radiology, X Ray, unwanted movement

Procedia PDF Downloads 449

Authors: Victor H. Benitez, Ramon V. Armas-Flores, Jesus H. Pacheco-Ramirez

Abstract:

Systems transforming solar energy into electrical power have emerged as a viable source of clean, renewable energy. Solar power tower technology is a good example of this type of system, which consists of several mobile mirrors, called heliostats, which reflect the sun's radiation to the same point, located on top of a tower at the center of heliostat field, for collection or transformation into another type of energy. The so-called Hermosillo’s Solar Platform (Plataforma Solar de Hermosillo, PSH, in Spanish) is a facility constituted with several heliostats, its aim and scope is for research purposes. In this paper, the implementation of a wireless communication system based on intelligent nodes is proposed in order to allow the communication and control of the heliostats in PSH. Intelligent nodes transmit information from one point to another, and can perform other actions that allow them to adapt to the conditions and limitations of a field of heliostats, thus achieving effective communication system. After deployment of the nodes in the heliostats, tests were conducted to measure the effectiveness of the communication, and determine the feasibility of using the proposed technologies. The test results were always positive, exceeding expectations held for its operation in the field of heliostats. Therefore, it was possible to validate the efficiency of the wireless communication system to be implemented in PSH, allowing communication and control of the heliostats.

Keywords: heliostat, intelligent node, solar energy, wireless communication

Procedia PDF Downloads 397

Authors: Melissa Lubitz

Abstract:

Water scarcity is one of the crucial challenges of our time. There needs to be a focus on creating a society where people and nature flourish, regardless of climatic conditions. One of the solutions we can look to is decentralized greywater recycling. The vision is simple. Every building has its own water source being greywater from the bath, shower, sink and washing machine. By treating this in the home, you can save 25-45% of potable water use and wastewater production, a reduction in energy consumption and CO2 emissions. This reusable water is clean, and safe to be used for toilet flushing, washing machine, and outdoor irrigation. Companies like Hydraloop have been committed to the greywater recycle-ready building concept for years. This means that drinking water conservation and water reuse are included as standards in the design of all new buildings. Sustainability and renewal go hand in hand. This vision includes not only optimizing water savings and waste reduction but also forging strong partnerships that bring this ambition to life. Together with regulators, municipalities and builders, a sustainable and water-conscious future is pursued. This is an opportunity to be part of a movement that is making a difference. By pushing this initiative forward, we become part of a growing community that resists dehydration, believes in sustainability, and is committed to a living environment at the forefront of change: sustainable living, where saving water is the norm and where we shape the future together.

Keywords: greywater, wastewater treatment, water conservation, circular water society

Procedia PDF Downloads 52

Authors: S. A. Krutovertsev, A. E. Tarasova, L. S. Krutovertseva, O. M. Ivanova

Abstract:

The aim of the work was to get stable sensitive films with good sensitivity to ethanolamine (C2H7NO) in air. Ethanolamine is used as adsorbent in different processes of gas purification and separation. Besides it has wide industrial application. Chemical sensors of sorption type are widely used for gas analysis. Their behavior is determined by sensor characteristics of sensitive sorption layer. Forming conditions and characteristics of chemical gas sensors based on nanostructured modified silica films activated by different admixtures have been studied. As additives molybdenum containing polyoxometalates of the eighteen series were incorporated in silica films. The method of hydrolythic polycondensation from tetraethyl orthosilicate solutions was used for forming such films in this work. The method’s advantage is a possibility to introduce active additives directly into an initial solution. This method enables to obtain sensitive thin films with high specific surface at room temperature. Particular properties make polyoxometalates attractive as active additives for forming of gas-sensitive films. As catalyst of different redox processes, they can either accelerate the reaction of the matrix with analyzed gas or interact with it, and it results in changes of matrix’s electrical properties Polyoxometalates based films were deposited on the test structures manufactured by microelectronic planar technology with interdigitated electrodes. Modified silica films were deposited by a casting method from solutions based on tetraethyl orthosilicate and polyoxometalates. Polyoxometalates were directly incorporated into initial solutions. Composite nanostructured films were deposited by drop casting method on test structures with a pair of interdigital metal electrodes formed at their surface. The sensor’s active area was 4.0 x 4.0 mm, and electrode gap was egual 0.08 mm. Morphology of the layers surface were studied with Solver-P47 scanning probe microscope (NT-MDT, Russia), the infrared spectra were investigated by a Bruker EQUINOX 55 (Germany). The conditions of film formation varied during the tests. Electrical parameters of the sensors were measured electronically in real-time mode. Films had highly developed surface with value of 450 m2/g and nanoscale pores. Thickness of them was 0,2-0,3 µm. The study shows that the conditions of the environment affect markedly the sensors characteristics, which can be improved by choosing of the right procedure of forming and processing. Addition of polyoxometalate into silica film resulted in stabilization of film mass and changed markedly of electrophysical characteristics. Availability of Mn3P2Mo18O62 into silica film resulted in good sensitivity and selectivity to ethanolamine. Sensitivity maximum was observed at weight content of doping additive in range of 30–50% in matrix. With ethanolamine concentration changing from 0 to 100 ppm films’ conductivity increased by 10-12 times. The increase of sensor’s sensitivity was received owing to complexing reaction of tested substance with cationic part of polyoxometalate. This fact results in intramolecular redox reaction which sharply change electrophysical properties of polyoxometalate. This process is reversible and takes place at room temperature.

Keywords: ethanolamine, gas analysis, polyoxometalate, silica film

Procedia PDF Downloads 200

Authors: Syali Pradhan, Neetu Jha

Abstract:

The Marigold flower is used in religious places for offering and decoration purpose every day. The flowers are discarded near trees or in aquatic bodies. This floral waste can be used for extracting dyes or oils. Still the secondary waste remains after processing which need to be addressed. This research aims to provide green and clean power using secondary floral waste available after processing. The carbonization of floral waste produce carbon material with high surface area and enhance active site for more reaction. The Hybrid supercapacitors are more stable, offer improved operating temperature and use less toxic material compared to battery. They provide enhanced energy density compared to supercapacitors. Hence, hybrid supercapacitor designed using waste material would be more practicable for future energy application. Here, we present the utilization of carbonized floral waste as supercapacitor electrode material. This material after carbonization gets graphitized and shows high surface area, optimum porosity along with high conductivity. Hence, this material has been tested as cathode electrode material for high performance zinc storage hybrid supercapacitor. High energy storage along with high stability has been obtained using this cathodic waste material as electrode.

Keywords: marigold, flower waste, energy storage, cathode, supercapacitor

Procedia PDF Downloads 60

Authors: Andrey A. Chernousov, Ben Y. B. Chan

Abstract:

The thermal behavior of a large-scale, phase change material (PCM) enhanced building envelope system was studied in regard to the need for pre-fabricated construction in subtropical regions. The proposed large-scale envelope consists of a reinforced aluminum skin, insulation core, phase change material and reinforced gypsum board. The PCM impact on an energy efficiency of an enveloped room was resolved by validation of the Energy Plus numerical scheme and optimization of a smart material location in the core. The PCM location was optimized by a minimization method of a cooling energy demand. It has been shown that there is good agreement between the test and simulation results. The optimal location of the PCM layer in Hong Kong summer conditions has been then recomputed for core thicknesses of 40, 60 and 80 mm. A non-dimensional value of the optimal PCM location was obtained to be same for all the studied cases and the considered external and internal conditions.

Keywords: thermal performance, phase change material, energy efficiency, PCM optimization

Procedia PDF Downloads 394

Authors: Alaa Y. Ali, Natalie P. Holmes, John Holdsworth, Warwick Belcher, Paul Dastoor, Xiaojing Zhou

Abstract:

Multi-layered graphene has been produced under low temperature chemical vapour deposition (CVD) growth conditions by utilizing an organic solvent and polymer film source. Poly(methylmethacrylate) (PMMA) was dissolved in chlorobenzene solvent and used as a drop-cast film carbon source on a quartz slide. A source temperature (T_source) of 180 °C provided sufficient carbon to grow graphene, as identified by Raman spectroscopy, on clean copper foil catalytic surfaces.  Systematic variation of hydrogen gas (H₂) flow rate from 25 standard cubic centimeters per minute (sccm) to 100 sccm and CVD temperature (T_growth) from 400 to 800 °C, yielded graphene films of varying quality as characterized by Raman spectroscopy. The optimal graphene growth parameters were found to occur with a hydrogen flow rate of 75 sccm sweeping the 180 °C source carbon past the Cu foil at 600 °C for 1 min. The deposition at 600 °C with a H₂ flow rate of 75 sccm yielded a 2D band peak with ~53.4 cm^-1 FWHM and a relative intensity ratio of the G to 2D bands (I_G/I_2D) of 0.21. This recipe fabricated a few layers of good quality graphene.

Keywords: graphene, chemical vapor deposition, carbon source, low temperature growth

Procedia PDF Downloads 149

Authors: Samuel Omachi

Abstract:

Since the creation of man, conflicts have remained a part and parcel of the society in spite of all measures adopted to keep them away. Conflicts are globally recognized as impediments of sustainable development and therefore regarded as undesirable, yet they are inevitable. However, some political leaders are better managers of conflicts than others. Those that manage conflicts poorly are backward and far from achieving economic development while efficient managers excel. The states in Africa fall into the category of poor managers of conflicts. Consequently, African continent has gained the notoriety of being the most crisis-ridden and poverty-stricken continent in the world in spite of her enormous resource endowment status. This problematic provided the compelling need for the discourse in the present study. Using the documentary analytical method, the paper x-rays the sources of conflicts, their effects and resolutions through peace education to allow room for economic development. The study concluded that African leaders needed to imbibe the culture of good governance with a key plank of peace building as a sine-qua-non for breaking the jinx that has tied the continent down to enable her catch up with her contemporaries in other parts of the competitive world.

Keywords: conflicts, resolutions, peace-building, development

Procedia PDF Downloads 274

Authors: Juan Xia, Jiaxu Yan, Ze Xiang Shen

Abstract:

The tuneable interlayer interactions in two-dimensional (2D) transition metal dichlcogenides (TMDs) offer an exciting platform for exploring new physics and applications by material variety, thickness, stacking sequence, electromagnetic filed, and stress/strain. Compared with the five methods mentioned above, high pressure is a clean and powerful tool to induce dramatic changes in lattice parameters and physical properties for 2D TMD materials. For instance, high pressure can strengthen the van der Waals interactions along c-axis and shorten the covalent bonds in atomic plane, leading to the typical first-order structural transition (2Hc to 2Ha for MoS2), or metallization. In particular, in the case of WTe₂, its unique symmetry endows the significant anisotropy and the corresponding unexpected properties including the giant magnetoresistance, pressure-induced superconductivity and Weyl semimetal states. Upon increasing pressure, the Raman peaks for WTe₂ at ~120 cm⁻¹, are gradually red-shifted and totally suppressed above 10 GPa, attributed to the possible structural instability of orthorhombic Td phase under high pressure and phase transition to a new monoclinic T' phase with inversion symmetry. Distinct electronic structures near Fermi level between the Td and T' phases may pave a feasible way to achieve the Weyl state tuning in one material without doping.

Keywords: 2D TMDs, electronic property, high pressure, first-principles calculations

Procedia PDF Downloads 221

Authors: Raghvendra Singh Yadav, Ivo Kuřitka

Abstract:

In this report, we studied the impact of Gd3+ substitution on structural, magnetic and electrical properties of CoFe2O4 nanoparticles synthesized by sonochemical method. X-ray diffraction pattern confirmed the formation of cubic spinel structure at low concentration of Gd3+ ions, however, GdFeO3 additional phase was observed at higher concentration of Gd3+ ions. Raman and Fourier Transform Infrared spectroscopy study also confirmed cubic spinel structure of Gd3+ substituted CoFe2O4 nanoparticles. The field emission scanning electron microscopy study revealed that Gd3+ substituted CoFe2O4 nanoparticles were in the range of 5-20 nm. The magnetic properties of Gd3+ substituted CoFe2O4 nanoparticles were investigated by using vibrating sample magnetometer. The variation in saturation magnetization, coercivity and remanent magnetization with Gd3+ concentration in CoFe2O4 nanoparticles was observed. The variation of real and imaginary part of dielectric constant, tan δ, and AC conductivity were studied at room temperature.

Keywords: spinel ferrites, nanoparticles, sonochemical method, magnetic properties

Procedia PDF Downloads 284

Authors: Zayd Parekh, Amish Prasad, Baraa Souman

Abstract:

Postural orthostatic tachycardia syndrome (POTS) is characterized by orthostatic intolerance due to an exaggerated tachycardia in response to standing upright. This exaggerated orthostatic tachycardia is defined as the heart rate (HR) rising 30 beats above a baseline value while supine or seated within ten minutes. The tachycardia can lead to symptoms of orthostatic intolerance such as palpitations, lightheadedness, exercise intolerance, fatigue, and anxiety. POTS can go undiagnosed for many years due to its similarities with other cardiac and psychiatric conditions and nonspecific presentation, making it crucial to raise awareness for it in the medical field. The following case study discusses a 30-year-old female who was evaluated in the emergency room several times before being referred to the clinic for POTS. An overview of what tests are performed with this patient is also provided, highlighting the diagnostic work-up for POTS and the process of ruling out other differentials being considered. Finally, the epidemiology, the various theories regarding its pathophysiology, the diagnostic process, and pharmacological and non-pharmacological management for POTS are reviewed.

Keywords: orthostatic intolerance, postural orthostatic tachycardia syndrome, syncope, tachycardia

Procedia PDF Downloads 67

Authors: Ming-Yeh Lu, Shiao-Shing Chen, Saikat Sinha Ray, Hung-Te Hsu

Abstract:

The submerged anaerobic osmotic membrane bioreactor (AnOMBR) integrated with periodic microfiltration (MF) extraction for simultaneous phosphorus and clean water recovery from wastewater was evaluated. A laboratory-scale AnOMBR used cellulose triacetate (CTA) membranes with effective membrane area of 130 cm² was fully submerged into a 5 L bioreactor at 30-35 ℃. Active layer was orientated to feed stream for minimizing membrane fouling and scaling. Additionally, a peristaltic pump was used to circulate magnesium sulphate (MgSO₄) solution applied as draw solution (DS). Microfiltration membrane periodically extracted about 1 L solution when the TDS reaches to 5 g/L to recover phosphorus and simultaneously control the salt accumulation in the bioreactor. During experiment progress, the average water flux was around 1.6 LMH. The AnOMBR process showed greater than 95% removal of soluble chemical oxygen demand (sCOD), nearly 100% of total phosphorous whereas only partial of ammonia was removed. On the other hand, the average methane production of 0.22 L/g sCOD was obtained. Subsequently, the overall performance demonstrates that a novel submerged AnOMBR system is potential for simultaneous wastewater treatment and resource recovery from wastewater. Therefore, the new concept of this system can be used to replace for the conventional AnMBR in the future.

Keywords: anaerobic treatment, forward osmosis, phosphorus recovery, membrane bioreactor

Procedia PDF Downloads 219

Authors: Nattawipa Pakasri

Abstract:

58S (60SiO2-36CaO-4P2O5), three-dimensionally ordered macroporous bioactive glasses (3DOM-BGs) were synthesized by the sol-gel method using dual templating methods. non-ionic surfactant Brij56 used as templates component produced mesoporous and the spherical PMMA colloidal crystals as one template component yielded either three-dimensionally ordered microporous products or shaped bioactive glass nanoparticles. The bioactive glass with aging step for 12 h at room temperature, no structure transformation occurred and the 3DOM structure was produced (Figure a) due to no shrinkage process between the aging step. After 48 h time of o 3DOM structure remained and, nanocube with ∼120 nm edge lengths and nanosphere particle with ∼50 nm was obtained (Figure c, d). PMMA packing templates have octahedral and tetrahedral holes to make 2 final shapes of 3DOM-BGs which is rounded and cubic, respectively. The ageing time change from 12h, 24h and 48h affected to the thickness of interconnecting macropores network. The wall thickness was gradually decrease after increase aging time.

Keywords: three-dimensionally ordered macroporous bioactive glasses, sol-gel method, PMMA, bioactive glass

Procedia PDF Downloads 103

Authors: Majid Arvan, Peyman Beygi, Sina Rokhsati

Abstract:

In-time detection of fire in buildings is of great importance. Employing intelligent methods in data processing in fire detection systems leads to a significant reduction of fire damage at lowest cost. In this paper, the raw data obtained from the fire detection sensor networks in buildings is processed by using intelligent methods based on neural networks and the likelihood of fire happening is predicted. In order to enhance the quality of system, the noise in the sensor data is reduced by analyzing wavelets and applying SVD technique. Meanwhile, the proposed neural network is trained using particle swarm optimization (PSO). In the simulation work, the data is collected from sensor network inside the room and applied to the proposed network. Then the outputs are compared with conventional MLP network. The simulation results represent the superiority of the proposed method over the conventional one.

Keywords: intelligent fire detection, neural network, particle swarm optimization, fire sensor network

Procedia PDF Downloads 371

Authors: Peter Sauer, Thomas Hinze, Petra Hofstedt

Abstract:

To avoid obstacles in the surrounding environment and to navigate to a given target belong to the most important tasks for mobile robots. According to these tasks different data structures are suitable. To avoid near obstacles, occupancy grid maps are an ideal representation of the surroundings. For less fine grained tasks, such as navigating from one room to another in an apartment, pure grid maps are inappropriate. Grid maps are very detailed, calculating paths to navigate between rooms based on grid maps would take too long. Instead, graph-based data structures, so-called topologies, turn out to be a proper choice for such tasks. In this paper we present two methods to dynamically create topologies from grid maps. Both methods are based on non-uniform grid maps. The topologies are generated on-the-fly and can easily be modified to represent changes in the environment. This allows a hybrid approach to control mobile robots, where, depending on the situation and the current task, either the grid map or the generated topology may be used.

Keywords: robot navigation, occupancy grids, topological maps, dynamic map creation

Procedia PDF Downloads 552

Authors: Beata Pospiech

Abstract:

Separation of metal ions from aqueous solutions is important as well as difficult process in hydrometallurgical technology. This process is necessary for obtaining of clean metals. Solvent extraction and membrane processes are well known as separation methods. Recently, ionic liquids (ILs) are very often applied and studied as extractants and carriers of metal ions from aqueous solutions due to their good extractability properties for various metals. This work discusses a method to separate copper(II) and iron(III) from hydrochloric acid solutions by solvent extraction and transport across polymer inclusion membranes (PIM) with the selected ionic liquids as extractants/ion carriers. Cyphos IL 101 (trihexyl(tetradecyl)phosphonium chloride), Cyphos IL 104 (trihexyl(tetradecyl)phosphonium bis(2,4,4 trimethylpentyl)phosphi-nate), trioctylmethylammonium thiosalicylate [A336][TS] and trihexyl(tetradecyl)phosphonium thiosalicylate [PR4][TS] were used for the investigations. Effect of different parameters such as hydrochloric acid concentration in aqueous phase on iron(III) and copper(II) extraction has been investigated. Cellulose triacetate membranes with the selected ionic liquids as carriers have been prepared and applied for transport of iron(IIII) and copper(II) from hydrochloric acid solutions.

Keywords: copper, iron, ionic liquids, solvent extraction

Procedia PDF Downloads 266

Authors: Hülya Kuru Mutlu, Mustafa Kulakcı, Uğur Serincan

Abstract:

The sun is one of the latest developments in renewable energy sources, which has a variety of application. Solar energy is the most preferred renewable energy sources because it can be used directly, it protects the environment and it is economic. In this work, we investigated that important parameter of GaAs-based solar cells with respect to the growth temperature. The samples were grown on (100) oriented p-GaAs substrates by solid source Veeco GEN20MC MBE system equipped with Ga, In, Al, Si, Be effusion cells and an Arsenic cracker cell. The structures of the grown samples are presented. After initial oxide desorption, Sample 1 and Sample 2 were grown at about 585°C and 535°C, respectively. From the grown structures, devices were fabricated by using the standard photolithography procedure. Current-voltage measurements were performed at room temperature (RT). It is observed that Sample 1 which was grown at 585°C has higher efficiency and fill factor compared to Sample 2. Hence, it is concluded that the growth temperature of 585°C is more suitable to grow GaAs-based solar cells considering our samples used in this study.

Keywords: molecular beam epitaxy, solar cell, current-voltage measurement, Sun

Procedia PDF Downloads 464