Search results for: high energy materials

Authors: Sebastian Kehne, Alexander Epple, Werner Herfs

Abstract:

A new method for optimal selection of components for multi-axes forward-feed drive systems is proposed in which the choice of motors, gear boxes and ball screw drives is optimized. Essential is here the synchronization of electrical and mechanical frequency behavior of all axes because even advanced controls (like H∞-controls) can only control a small part of the mechanical modes – namely only those of observable and controllable states whose value can be derived from the positions of extern linear length measurement systems and/or rotary encoders on the motor or gear box shafts. Further problems are the unknown processing forces like cutting forces in machine tools during normal operation which make the estimation and control via an observer even more difficult. To start with, the open source Modelica Feed Drive Library which was developed at the Laboratory for Machine Tools, and Production Engineering (WZL) is extended from one axis design to the multi axes design. It is capable to simulate the mechanical, electrical and thermal behavior of permanent magnet synchronous machines with inverters, different gear boxes and ball screw drives in a mechanical system. To keep the calculation time down analytical equations are used for field and torque producing equivalent circuit, heat dissipation and mechanical torque at the shaft. As a first step, a small machine tool with a working area of 635 x 315 x 420 mm is taken apart, and the mechanical transfer behavior is measured with an impulse hammer and acceleration sensors. With the frequency transfer functions, a mechanical finite element model is built up which is reduced with substructure coupling to a mass-damper system which models the most important modes of the axes. The model is modelled with Modelica Feed Drive Library and validated by further relative measurements between machine table and spindle holder with a piezo actor and acceleration sensors. In a next step, the choice of possible components in motor catalogues is limited by derived analytical formulas which are based on well-known metrics to gain effective power and torque of the components. The simulation in Modelica is run with different permanent magnet synchronous motors, gear boxes and ball screw drives from different suppliers. To speed up the optimization different black-box optimization methods (Surrogate-based, gradient-based and evolutionary) are tested on the case. The objective that was chosen is to minimize the integral of the deviations if a step is given on the position controls of the different axes. Small values are good measures for a high dynamic axes. In each iteration (evaluation of one set of components) the control variables are adjusted automatically to have an overshoot less than 1%. It is obtained that the order of the components in optimization problem has a deep impact on the speed of the black-box optimization. An approach to do efficient black-box optimization for multi-axes design is presented in the last part. The authors would like to thank the German Research Foundation DFG for financial support of the project “Optimierung des mechatronischen Entwurfs von mehrachsigen Antriebssystemen (HE 5386/14-1 | 6954/4-1)” (English: Optimization of the Mechatronic Design of Multi-Axes Drive Systems).

Keywords: ball screw drive design, discrete optimization, forward feed drives, gear box design, linear drives, machine tools, motor design, multi-axes design

Procedia PDF Downloads 272

Authors: Marcia J. Watson

Abstract:

The “school-to-prison pipeline” is a widely known phenomenon within education. Although data surrounding this epidemic is daunting, we coin the term “school-to-postsecondary pipeline” to explore proactive strategies that are currently working in K-12 education for African American students. The assumption that high school graduation, postsecondary matriculation, and social success are not the assumed norms for African American youth, positions the term “school-to-postsecondary pipeline” as the newly casted advocacy term for African American educational success. Using secondary data from the Children’s Defense Fund and the U.S. Department of Education’s Office of Civil Rights, we examine current conditions of educational accessibility and attainment for African American students, and provide effective strategies for classroom teachers, administrators, and parents to use for the immediate implementation in schools. These strategies include: (a) engaging instruction, (b) relevant curriculum, and (c) utilizing useful enrichment and community resources. By providing proactive steps towards the school-to-postsecondary pipeline, we hope to counter the docility of the school-to-prison pipeline as the assumed reality for African American youth.

Keywords: college access, higher education, school-to-prison pipeline, urban education reform

Procedia PDF Downloads 523

Authors: Terence Lucero F. Menor, Manolo G. Mena, Herman D. Mendoza

Abstract:

Solder pastes are widely used in creating mechanical, thermal and electrical connection between electronic components. Continued miniaturization of consumer electronics drives manufacturers to achieve smaller, lighter, and faster electronic packages at low cost. This faces them to the difficult challenge of dispensing solder pastes in extremely precise and repeatable manner. The most common problem in solder paste dispensing is the clogging of dispensers which results from agglomeration and settling of solder powders leading to increase on the effective particle size and uneven distribution of particles in the mixture. In this work, microelectrophoresis was employed to investigate the effect of pH and KNO₃ concentration on the electrokinetic behavior and stability of SAC305, PbSn5Ag2.5 and Sn powders in aqueous media. Results revealed that the electrokinetic behavior of the three types of solder powders are similar, which was attributed to high SnO₂ content on the surface of the particles. Electrokinetic measurements showed that the zeta potentials of the solder powders are highly dependent on pH and KNO₃ concentration with isoelectric points ranging from 3.5 to 5.5. Results were verified using stability tests.

Keywords: electrokinetic behavior, isoelectric point, solder powder, stability, surface analysis

Procedia PDF Downloads 217

Authors: Anna Pick Kiong Ling, Jia May Chin, Rhun Yian Koh, Ying Pei Wong

Abstract:

Background: Uncontrolled inflammation may cause serious inflammatory diseases if left untreated. Non-steroidal anti-inflammatory drug (NSAIDs) is commonly used to inhibit pro-inflammatory enzymes, thus, reduce inflammation. However, long term administration of NSAIDs leads to various complications. Medicinal plants are getting more attention as it is believed to be more compatible with human body. One of them is a flavonoid-containing medicinal plants, Strobilanthes crispus which has been traditionally claimed to possess anti-inflammatory and antioxidant activities. Nevertheless, its anti-inflammatory activities are yet to be scientifically documented. Objectives: This study aimed to examine the anti-inflammatory activity of S. crispus by investigating its effects on intracellular oxidative stress and prostaglandin E₂ (PGE₂) levels. Materials and Methods: In this study, the Maximum Non-toxic Dose (MNTD) of methanol extract of both leaves and stems of S. crispus was first determined using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenytetrazolium Bromide (MTT) assay. The effects of S. crispus extracts at MNTD and half MNTD (½MNTD) on intracellular ROS as well as PGE₂ levels in 1.0 µg/mL LPS-stimulated RAW 264.7 macrophages were then be measured using DCFH-DA and a competitive enzyme immunoassay kit, respectively. Results: The MNTD of leaf extract was determined as 700µg/mL while for stem was as low as 1.4µg/mL. When LPS-stimulated RAW 264.7 macrophages were subjected to the MNTD of S. crispus leaf extract, both intracellular ROS and PGE₂ levels were significantly reduced. In contrast, stem extract at both MNTD and ½MNTD did not significantly reduce the PGE₂ level, but significantly increased the intracellular ROS level. Conclusion: The methanol leaf extract of S. crispus may possess anti-inflammatory properties as it is able to significantly reduce the intracellular ROS and PGE₂ levels of LPS-stimulated cells. Nevertheless, further studies such as investigating the interleukin, nitric oxide and cytokine tumor necrosis factor-α (TNFα) levels has to be conducted to further confirm the anti-inflammatory properties of S. crispus.

Keywords: anti-inflammatory, natural products, prostaglandin E2, reactive oxygen species

Procedia PDF Downloads 269

Authors: Tonga Agadi Danladi, Ajao Wasiu Bamidele, Terdue Dyeko

Abstract:

Recent advancement in microwave communications technologies especially in telecommunications and broadcasting have resulted in congestion on the frequencies below 10GHz. This has forced microwave designers to look for high frequencies. Unfortunately for frequencies greater than 10GHz rain becomes one of the main factors of attenuation in signal strength. At frequencies from 10GHz upwards, rain drop sizes leads to outages that compromises the availability and quality of service this making it a critical factor in satellite link budget design. Rain rate and rain attenuation predictions are vital steps to be considered when designing microwave satellite communication link operating at Ku-band frequencies (112-18GHz). Unreliable rain rates data in the tropical regions of the world like Nigeria from radio communication group of the international Telecommunication Union (ITU-R) makes it difficult for microwave engineers to determine a realistic rain margin that needs to be accommodated in satellite link budget design in such region. This work presents an empirical tool for predicting the amount of signal due to rain on DBS signal operating at the Ku-band.

Keywords: attenuation, Ku-Band, microwave communication, rain rates

Procedia PDF Downloads 467

Authors: Sadi-Guettaf Hassiba, Hadj-Bekkouche Fatima

Abstract:

Dexamethasone (Dex) is a synthetic glucocorticoid that is used in therapy. However prolonged treatments with high doses are often required. This causes side effects that interfere with the activity of several endocrine systems, including the gonadotropic axis. The aim of our study is to determine the effect of Dex on testicular function in prepubertal Wistar rats. Newborn Wistar rats are submitted to intraperitoneal injection of Dex (1μg of Dex dissolved in NaCl 0.9% / 5g bw) for 20 days and then sacrificed at the age of 40days. A control group received NaCl 0.9%. The rat is weighed daily. The plasmatic levels of testosterone, LH and FSH were measured by radioimmunoassay. A histo-morphometric study was performed on sections of testis. Treated groups showed a significant decrease in body weight (p < 0.05), testis weight (p < 0.05) and plasma levels of testosterone (p < 0.05), of LH (P < .05) and FSH (p> 0.05). There is a reduction of seminiferous tubules average diameter and also of the seminiferous epithelium thickness with an increasing of lumen tubular. The diameter of the Leydig cells and Sertoli cell nucleus is also significantly reduced. Spermatogenesis is blocked at the stage round spermatid unlike witnesses or elongated spermatid stage is found. These results suggest that Dex administered during neonatal life influences testicular activity in the long term.

Keywords: dexamethasone, FSH, LH, rat, testis, testosterone

Procedia PDF Downloads 240

Authors: Emmanuel Adu-Ofori, Richard Amfo-Otu, Isaac O. A. Hodgson

Abstract:

The study was conducted to determine the treatment performance of waste stabilization ponds in Akosombo. A total of 15 samples were taken for four consecutive months from the inlet, facultative pond and outlet of maturation pond. The samples were preserved and transported to Water Research Institute for laboratory analysis. The wastewater quality parameters analysed to assess the treatment performance were total suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonia and phosphate. The results of the laboratory analysis showed that the ponds achieved TSS, BOD and COD removals of about 30, 82 and 75 per cent respectively. Statistically, the BOD (t = 10.27, p = 6.68 x 10-6) and COD (t = 4.23, p = 0.0029) of the raw sewage were significantly different from the total effluent at 95% confidence interval. The ammonia and phosphate removal was as high as 92% and 84% respectively. The quality parameters analysed for the final effluent from the Waste Stabilisation Pond was within the EPA guideline values. The general treatment performances were very good with respect to the parameters studied and does not pose threat to the receiving water body. A further study to examine the bacteriological treatment performance was recommended.

Keywords: waste stabilization pond, wast water, treatment performance, nutrient, Ghana

Procedia PDF Downloads 306

Authors: A. Kachmazova, A. Shadiev, Y. Teterin, P. Yartcev

Abstract:

Introduction: Biliary calculi disease (LCS) still occupies the leading position among urgent diseases of the abdominal cavity, manifesting itself from asymptomatic course to life-threatening states. Nowadays arsenal of diagnostic methods for choledocholithiasis is quite wide: ultrasound, hepatobiliscintigraphy (HBSG), magnetic resonance imaging (MRI), endoscopic retrograde cholangiography (ERCP). Among them, transabdominal ultrasound (TA ultrasound) is the most accessible and routine diagnostic method. Nowadays ERCG is the "gold" standard in diagnosis and one-stage treatment of biliary tract obstruction. However, transpapillary techniques are accompanied by serious postoperative complications (postmanipulative pancreatitis (3-5%), endoscopic papillosphincterotomy bleeding (2%), cholangitis (1%)), the lethality being 0.4%. GBSG and MRI are also quite informative methods in the diagnosis of choledocholithiasis. Small size of concrements, their localization in intrapancreatic and retroduodenal part of common bile duct significantly reduces informativity of all diagnostic methods described above, that demands additional studying of this problem. Materials and Methods: 890 patients with the diagnosis of cholelithiasis (calculous cholecystitis) were admitted to the Sklifosovsky Scientific Research Institute of Hospital Medicine in the period from August, 2020 to June, 2021. Of them 115 people with mechanical jaundice caused by concrements in bile ducts. Results: Final EUS diagnosis was made in all patients (100,0%). In all patients in whom choledocholithiasis diagnosis was revealed or confirmed after EUS, ERCP was performed urgently (within two days from the moment of its detection) as the X-ray operation room was provided; it confirmed the presence of concrements. All stones were removed by lithoextraction using Dormia basket. The postoperative period in these patients had no complications. Conclusions: EUS is the most informative and safe diagnostic method, which allows to detect choledocholithiasis in patients with discrepancies between clinical-laboratory and instrumental methods of diagnosis in shortest time, that in its turn will help to decide promptly on the further tactics of patient treatment. We consider it reasonable to include EUS in the diagnostic algorithm for choledocholithiasis. Disclosure: Nothing to disclose.

Keywords: endoscopic ultrasonography, choledocholithiasis, common bile duct, concrement, ERCP

Procedia PDF Downloads 73

Authors: Valentina Milanova, Kalina Mihaylova, Iva Lazarova

Abstract:

The mechanisms by which female genital infections are detected are varied and include clinician-collected high vaginal swabs, clinician-collected endocervical swabs, patient-collected vaginal swabs, and first-pass urine samples. Vaginal health screening has chronically low rates of uptake. This highlights the unmet need for a screening tool with comparable diagnostic accuracy which is familiar, convenient and easy to use for people. The Daye™ medical grade tampon offers an alternative to traditional sampling methods with the potential of increasing screening uptake among people previously too embarrassed or busy to attend gynecological appointments. In this white paper, the results of stability studies and a comparative clinical trial are discussed to assess the suitability of the device for the collection of vaginal samples for various clinical assessments. The tampon has demonstrated good sample stability and comparable sample quality compared to a self-collected vaginal swab and a clinician-collected cervical swab.

Keywords: vaginal microbiome, vaginal infections, gynaecological infections, female health, menstrual tampons, in vitro diagnostics

Procedia PDF Downloads 84

Authors: Savitri Siddanagoudra, Shantala Herlekar, Priya Arjunwadekar

Abstract:

Background: The physiological response to water drinking in healthy subjects is an integrated response with an increase in sympathetic vasoconstrictor activity with induced bradycardia. Obesity is a modern pandemic, implicated in the pathogenesis of cardiovascular disease. In autonomic failure patients, water drinking has been shown the increased high blood pressure and bradycardia. Acute effects of ice water ingestion on blood pressure (BP) in relation to body mass index (BMI) is not addressed in literature. Objectives: Objective of this study is to evaluate BP before and after ingestion of cold water in all the three groups. Methods and Material: 60 healthy subjects between the age group of 18-24 yrs were selected and assigned into 3 groups based on BMI. BMI less than and equal to 25 kg/m2 is selected as Normal BMI group ,between 25- 29 kg/m2 as Overweight and BMI more than and equal to 30 kg/m2 as Obese. Procedure: Basal and after ingestion of 250 ml of cold water (7 0C ± 0.5 0C)BP was recorded in all the 3 groups. Results: Basal and after ice water ingestion BP increased statistically in all 3 groups. Conclusion: On acute ingestion of ice water overweight, obese may have more sympathoexcitaion compared to normal subjects.

Keywords: blood pressure, body mass index, ice water, symathoexcitation

Procedia PDF Downloads 152

Authors: Nura Brimo, Dilek Cokeliler Serdaroglu, Tansel Uyar, Busra Uysal, Elif Bahar Cakici, Miris Dikmen, Zerrin Canturk

Abstract:

Background: A combination of antibiotics, including metronidazole (MET), ciprofloxacin (CIP), and minocycline (MINO), has been demonstrated to disinfect bacteria in necrotic teeth before regenerative processes. It has been presented clinically that antibiotic pastes may drive to possible stem cell death and difficulties in removing from the canal system, which can limit the regenerative procedure. This study was designed to (1) synthesize nanofibrous webs containing various concentrations of different medicaments (triple, double, and calcium hydroxide,Ca(OH)2), and (2) coat thiselectrospun fibrous gutta-percha (GP) cones. Methods: Poly(vinylpyrrolidone) (PVP)-based electrospun fibrous webs were processed with low medicaments concentrations. Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), and X-Ray Photoelectron Spectroscopy (XPS) were carried out to investigate fiber morphology, antibiotic incorporation, and characterized GP-coated fibrous webs, respectively. The chemical and physical properties of dentine were carried out via Fourier Transform Infrared Spectroscopy (FTIR) and Nano-SEM, respectively. The antimicrobial properties of the different fibrous webs were assessed against various bacteria by direct nanofiber/bacteria contact. Cytocompatibility was measured by applying the MTT method. Results: The mean fiber diameter of the experiment groups of medicament-containing fibers ranged in the nm scale and was significantly smaller than PVP fibers. EDX analysis confirmed the presence of medicaments in the nanofibers. XPS analysis presented a complete coating of the fibers with GPs; FTIR and Nano-SEM showed no chemical and physical configuration of intracanal medicaments on the dentine surface. Meanwhile, nanofibrous webs led to a significant reduction in the percentage of viable bacteria compared with the negative control and PVP. Conclusion: Our findings suggest that TA-NFs, DA-NFs, and Cₐ(OH)₂)-NFs coated GP cones have significant potential in eliminating intracanal bacteria, cell-friendly behavior, and clinical usage features.

Keywords: drug delivery, drug carrier, electrospinning, nano/microfibers, regenerative endodontic, morphology

Procedia PDF Downloads 100

Authors: Nizika Sorokhaibam

Abstract:

With the collapse of the Soviet Union in 1989, that marked the end of the prolonged struggle of ideologies between capitalism of the United States of America and communism of the Soviet Union, the world entered a new era of free markets, trade and economic liberalization. Through analysis of various literatures on North Korea, this study focuses on the impact of Globalization on North Korea- its people, economy and the regime. The study also takes a glance at the Juche ideology, which was crafted by the Supreme Leader Kim Il Sung, for the people of DPRK and its role and influence in shaping the North Korean economy. The new buzz word being Globalization, as businesses started to expand on international scale, demanding the need for co-operation, connectivity and interdependence of countries around the world. States tilted their focus towards industrialization, production of raw materials, production of goods to meet the growing demands and grabbing markets for the manufactured products. This became the norm as many newly independent countries adopted democracy and aligned their views with globalization processes. Socialist and communist regimes either fell one after the other to join the globalization trend or reformed their economic system to meet the globalization trends. However, even after staying isolated for more than six decades, Democratic People’s Republic of Korea, the Hermit Kingdom, refuses to open up its economy to the globalised world. North Korean regime still controls all the sectors of the country and no trade and investment freedom is given to the people. North Korea vigorously makes efforts to emphasize on its Juche ideology of self-sustenance and self-reliance to keep away from actively engaging in global trade and process of globalization, which they refer to as “Americanization” of the world. Nevertheless, the reality is that North Korea’s economy is not self sustained and is collapsing from within, which led them to solicit foreign aid from the United States of America, South Korea (Republic of Korea) and People’s Republic of China. The regime needs to implement reforms and make adjustments for the economy to survive in the competing world.

Keywords: economic globalization, economic isolation, Juche, North Korea

Procedia PDF Downloads 252

Authors: Anan Alssbaiheen, Steve Love

Abstract:

Given the lack of research into potential opportunities and challenges which are likely to be associated with the implementation of mobile services in developing countries including Saudi Arabia, the research reported here investigated the challenges and opportunities which are associated with the implementation of mobile government services in Saudi Arabia. By collecting data through surveys from 103 Saudi citizens and 46 employees working at the Ministry of Communication and Information Technology Saudi Arabia, this study indicates that the high level of mobile penetration in the country offers an opportunity for Saudi Arabian government to offer mobile government services in the country. The results also suggest that though a large percentage of populations do not have access to mobile technologies, there is still a strong desire among users for the provision of mobile government services. Moreover, the results suggest that effective implementation of mobile government services would help to increase the technological development of Saudi Arabia. However, there are certain challenges which may prevent the effective implementation of such services. First, there does not appear to be a sufficient level of understanding among the Saudi Arabian population about the benefits which are associated with mobile government services. Secondly, the results suggest that the implementation of the services needs to be closely tailored and personalised to the individual needs of target users. Finally, the lack of access to mobile technologies would be a challenge to the successful introduction of these services.

Keywords: challenges, e-government, mobile government, opportunities

Procedia PDF Downloads 404

Authors: Fikremariam Beyene, Getachew Bekele

Abstract:

Ethiopia is currently on the move with various projects to raise the amount of power generated in the country. The progress observed in recent years indicates this fact clearly and indisputably. The rural electrification program, the modernization of the power transmission system, the development of wind farm is some of the main accomplishments worth mentioning. As it is well known, currently, wind power is globally embraced as one of the most important sources of energy mainly for its environmentally friendly characteristics, and also that once it is installed, it is a source available free of charge. However, integration of wind power plant with an existing network has many challenges that need to be given serious attention. In Ethiopia, a number of wind farms are either installed or are under construction. A series of wind farm is planned to be installed in the near future. Ashegoda Wind farm (13.2°, 39.6°), which is the subject of this study, is the first large scale wind farm under construction with the capacity of 120 MW. The first phase of 120 MW (30 MW) has been completed and is expected to be connected to the grid soon. This paper is concerned with the investigation of the wind farm interaction with the national grid under transient operating condition. The main concern is the fault ride through (FRT) capability of the system when the grid voltage drops to exceedingly low values because of short circuit fault and also the active and reactive power behavior of wind turbines after the fault is cleared. On the wind turbine side, a detailed dynamic modelling of variable speed wind turbine of a 1 MW capacity running with a squirrel cage induction generator and full-scale power electronics converters is done and analyzed using simulation software DIgSILENT PowerFactory. On the Ethiopian electric power corporation side, after having collected sufficient data for the analysis, the grid network is modeled. In the model, a fault ride-through (FRT) capability of the plant is studied by applying 3-phase short circuit on the grid terminal near the wind farm. The results show that the Ashegoda wind farm can ride from voltage deep within a short time and the active and reactive power performance of the wind farm is also promising.

Keywords: squirrel cage induction generator, active and reactive power, DIgSILENT PowerFactory, fault ride-through capability, 3-phase short circuit

Procedia PDF Downloads 151

Authors: Issa Qabaja, Fadi Thabtah

Abstract:

Email phishing classification is one of the vital problems in the online security research domain that have attracted several scholars due to its impact on the users payments performed daily online. One aspect to reach a good performance by the detection algorithms in the email phishing problem is to identify the minimal set of features that significantly have an impact on raising the phishing detection rate. This paper investigate three known feature selection methods named Information Gain (IG), Chi-square and Correlation Features Set (CFS) on the email phishing problem to separate high influential features from low influential ones in phishing detection. We measure the degree of influentially by applying four data mining algorithms on a large set of features. We compare the accuracy of these algorithms on the complete features set before feature selection has been applied and after feature selection has been applied. After conducting experiments, the results show 12 common significant features have been chosen among the considered features by the feature selection methods. Further, the average detection accuracy derived by the data mining algorithms on the reduced 12-features set was very slight affected when compared with the one derived from the 47-features set.

Keywords: data mining, email classification, phishing, online security

Procedia PDF Downloads 417

Authors: Muhammad Umar Mushtaq, Muhammad Bilal Khan Niazi, Nouman Ahmad, Dooa Arif

Abstract:

Apart from organic dyes, heavy metals such as Pb, Ni, Cr, and Cu are present in textile effluent and pose a threat to humans and the environment. Many studies on removing heavy metallic ions from textile wastewater have been conducted in recent decades using metal-organic frameworks (MOFs). In this study new polyether sulfone ultrafiltration membrane, modified with Cu/Co and Cu/Zn-based bimetal-organic frameworks (MOFs), was produced. Phase inversion was used to produce the membrane, and atomic force microscopy (AFM), scanning electron microscopy (SEM) were used to characterize it. The bimetallic MOFs-based membrane structure is complex and can be comprehended using characterization techniques. The bimetallic MOF-based filtration membranes are designed to selectively adsorb specific contaminants while allowing the passage of water molecules, improving the ultrafiltration efficiency. MOFs' adsorption capacity and selectivity are enhanced by functionalizing them with particular chemical groups or incorporating them into composite membranes with other materials, such as polymers. The morphology and performance of the bimetallic MOF-based membrane were investigated regarding pure water flux and metal ion rejection. The advantages of developed bimetallic MOFs based membranes for wastewater treatment include enhanced adsorption capacity because of the presence of two metals in their structure, which provides additional binding sites for contaminants, leading to a higher adsorption capacity and more efficient removal of pollutants from wastewater. Based on the experimental findings, bimetallic MOF-based membranes are more capable of rejecting metal ions from industrial wastewater than conventional membranes that have already been developed. Furthermore, the difficulties associated with operational parameters, including pressure gradients and velocity profiles, are simulated using Ansys Fluent software. The simulation results obtained for the operating parameters are in complete agreement with the experimental results.

Keywords: bimetallic MOFs, heavy metal ions, industrial wastewater treatment, ultrafiltration.

Procedia PDF Downloads 77

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

Abstract:

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

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

Procedia PDF Downloads 540

Authors: Tao Youjun, Zhao Younan

Abstract:

The separation effect of fine coal can be improved by the process of pre-desliming. It was significantly enhanced when the fine coal was processed using Falcon concentrator with the removal of -45um coal slime. Ultrafine classification tests using Krebs classification cyclone with annular rinse water showed that increasing feeding pressure can effectively avoid the phenomena of heavy particles passing into overflow and light particles slipping into underflow. The increase of rinse water pressure could reduce the content of fine-grained particles while increasing the classification size. The increase in feeding concentration had a negative effect on the efficiency of classification, meanwhile increased the classification size due to the enhanced hindered settling caused by high underflow concentration. As a result of optimization experiments with response indicator of classification efficiency which based on orthogonal design using Design-Expert software indicated that the optimal classification efficiency reached 91.32% with the feeding pressure of 0.03MPa, the rinse water pressure of 0.02MPa and the feeding concentration of 12.5%. Meanwhile, the classification size was 49.99 μm which had a good agreement with the predicted value.

Keywords: hydrocyclone, ultrafine classification, slime, classification efficiency, classification size

Procedia PDF Downloads 153

Authors: S. Krustev, V. Angelova, K. Ivanov, P. Zaprjanova

Abstract:

Approximately a dozen trace elements are vital for the development of all plants and some other elements are significant for some species. Heavy metals do not belong to this group of elements that are essential to plants, but some of them such as copper and zinc, have a dual effect on their growth. Concentration levels of these elements in the different regions of the world vary considerably. Their high concentrations in some parts of Central and Eastern Europe cause concern for human health and degrade the quality of agricultural produce from these areas. This study aims to compare the prevalence and levels of the major trace elements in some rural areas of Central and Eastern Europe. Soil samples from different regions of the Czech Republic, Slovakia, Austria, Hungary, Serbia, Romania, Bulgaria and Greece far from large industrial centers have been studied. The main methods for their determination are the atomic spectral techniques – atomic absorption and plasma atomic emission. As a result of this study, data on microelements levels in soils of 17 points from the main grain-producing regions of Central and Eastern Europe are presented and systematized. The content of trace elements was in the range of 5.0-84.1 mg.kg⁻¹ for Cu, 0.3-1.4 mg.kg⁻¹ for Cd, 26.1-225.5 mg.kg⁻¹ for Zn, 235.5-788.6 mg.kg⁻¹ for Mn and 4.1-25.8 mg.kg⁻¹ for Pb.

Keywords: trace elements, heavy metals, agricultural soils, Central and Eastern Europe

Procedia PDF Downloads 153

Authors: Aroona Hashmi

Abstract:

The prime motive for this endeavor was to explore the tenth grade English class students’ preferred learning styles studying in government secondary school so that English subject teachers could tailor their pedagogical strategies in relation to their students learning needs. The further aim of this study was to identify any significance difference among the students on a gender basis, area basis and different categories of school basis. The population of this study consisting of all the secondary level schools working in the government sector and positioned in the province of Punjab. The multi-stage cluster sampling method was employed while selecting the study sample from the population. The scale used for the identification of students’ learning styles in this study was developed by Grasha-Riechmann. The data collected through learning style scale was analyzed by employing descriptive statistics technique. The results from data analysis depict that learning styles of the majority of students found to be Collaborative and Competitive. Overall, no considerable difference was surfaced between male-female, urban-rural, general-other categories of 10th grade English class students learning styles.

Keywords: learning style, learning style scale, grade, government sector

Procedia PDF Downloads 329

Authors: S. Alireza Mirghasemi, Narges Rahimi Gabaran

Abstract:

Although sacral fractures in children are rare due to the fact that the occurrence of pelvic fracture is not common in childhood. Sacral fractures present a high risk of neurological damage. This kind of fracture is often missed because the routine pelvic X-rays imaging scarcely show this fracture. Also, the treatment is controversial, and it ranges from fine reduction to conservative treatments without any try to reduce the dislocation. In this article, a case of fracture dislocation of S1 and S2 along with a suggested diagnostic test and treatment based on similar cases are presented. The case investigates a 14-year-old boy who entered the hospital one week after a car accident that knocked him to the ground in crawling position and a rack fell down on his body. Pain and tenderness in the sacral region and a fracture in the left leg were notable--we detected incomplete bilateral palsy of L5, S1 and S2 roots. In radiographs of the spine fracture dislocation of S1, the sacral fracture was seen. The treatment included a skeletal traction with a halo over the patient’s head and two femoral pins. After one week, another surgery was performed in order to stabilize and reduce the fracture, and we employed a posterior approach with CD and a pedicular screw. After two years of follow-up, the fracture is completely cured without any loss of reduction.

Keywords: adolescent, fracture in adolescent, fracture dislocation, sacrum

Procedia PDF Downloads 277

Authors: F. Felipe

Abstract:

Air Defense Systems contain high-value assets that are expected to fulfill their mission for several years - in many cases, even decades - while operating in a fast-changing, technology-driven environment. Thus, it is paramount that decision-makers can assess how effective an Air Defense System is in the face of new developing threats, as well as to identify the bottlenecks that could jeopardize the security of the airspace of a country. Given the broad extent of activities and the great variety of assets necessary to achieve the strategic objectives, a systems approach was taken in order to delineate the core requirements and the physical architecture of an Air Defense System. Then, value-focused thinking helped in the definition of the measures of effectiveness. Furthermore, analytical methods were applied to create a formal structure that preliminarily assesses such measures. To validate the proposed methodology, a powerful simulation was also used to determine the measures of effectiveness, now in more complex environments that incorporate both uncertainty and multiple interactions of the entities. The results regarding the validity of this methodology suggest that the approach can support decisions aimed at enhancing the capabilities of Air Defense Systems. In conclusion, this paper sheds some light on how consolidated approaches of Systems Engineering and Operations Research can be used as valid techniques for solving problems regarding a complex and yet vital matter.

Keywords: air defense, effectiveness, system, simulation, decision-support

Procedia PDF Downloads 150

Authors: Chanpen Meenakorn

Abstract:

This research aims to study; (1) behavior of the tourists affecting the satisfaction level of tourism at the Amphawa floating market in Samut Songkhram province, (2) to study the satisfaction level of tourism at the Amphawa floating market. The research method will use quantitative research; data was collected by questionnaires distributed to the tourist who visits the Amphawa floating market for 480 samples. Data was analyzed by SPSS software to process descriptive statistic including frequency, percentage, mean, standard deviation and inferential statistic is t-test, F-test, and chi-square. The results showed that the behavior of tourists had known tourist attractions in the province comes from the mouth of relatives and friends suggested that he come here before and the reasons to visit is to want to pay homage to the various temples for the frequency to visit travel an average of 2-4 times and  the satisfaction of the tourists in the province found that the satisfaction level of tourists in the province at the significant level of the place, convenient  and services have a high level of satisfaction.

Keywords: amphawa floating market behavior of the tourists, satisfaction level, sustainable tourism, Samut Songkhram province

Procedia PDF Downloads 352

Authors: M. E. Abalaka, S. Y. Daniyan, S. O. Adeyemo, D. Damisa

Abstract:

Gold nanoparticles (AuNPs) have gained increasing interest in recent times. This is greatly due to their special features, which include unusual optical and electronic properties, high stability and biological compatibility, controllable morphology and size dispersion, and easy surface functionalization. In typical synthesis, AuNPs were produced by reduction of gold salt AuCl4 in an appropriate solvent. A stabilizing agent was added to prevent the particles from aggregating. The antibacterial activity of different sizes of gold nanoparticles was investigated against Staphylococcus aureus, Salmonella typhi and Pseudomonas pneumonia using the disk diffusion method in a Müeller–Hinton Agar. The Au-NPs were effective against all bacteria tested. That the Au-NPs were successfully synthesized in suspension and were used to study the antibacterial activity of the two medicinal plants against some bacterial pathogens suggests that Au-NPs can be employed as an effective bacteria inhibitor and may be an effective tool in medical field. The study clearly showed that the Au-NPs exhibiting inhibition towards the tested pathogenic bacteria in vitro could have the same effects in vivo and thus may be useful in the medical field if well researched into.

Keywords: gold nanoparticles, Gomphrena celesioides, Prunus amygdalus, pathogens

Procedia PDF Downloads 293

Authors: Mohamed A. G. H. Abdalsadig, Amir Nourian, G. G. Nasr, Meisam Babaie

Abstract:

Gas lift optimization is becoming more important now a day in petroleum industry. A proper lift optimization can reduce the operating cost, increase the net present value (NPV) and maximize the recovery from the asset. A widely accepted definition of gas lift optimization is to obtain the maximum output under specified operating conditions. In addition, gas lift, a costly and indispensable means to recover oil from high depth reservoir entails solving the gas lift optimization problems. Gas lift optimization is a continuous process; there are two levels of production optimization. The total field optimization involves optimizing the surface facilities and the injection rate that can be achieved by standard tools softwares. Well level optimization can be achieved by optimizing the well parameters such as point of injection, injection rate, and injection pressure. All these aspects have been investigated and presented in this study by using experimental data and PROSPER simulation program. The results show that the well head pressure has a large influence on the gas lift performance and also proved that smart gas lift valve can be used to improve gas lift performance by controlling gas injection from down hole. Obtaining the optimum gas injection rate is important because excessive gas injection reduces production rate and consequently increases the operation cost.

Keywords: optimization, production rate, reservoir pressure effect, gas injection rate effect, gas injection pressure

Procedia PDF Downloads 397

Authors: P. V. Krupakara

Abstract:

This paper deals with the high corrosion resistance developed by the hybrid metal matrix composites when compared with that of matrix alloy. Matrix selected is Al6061. Reinforcements selected are graphite and red mud particulates. The composites are prepared using liquid melt metallurgy technique using vortex method. Metal matrix composites containing 2 percent graphite and 2 percent red mud, 2 percent graphite and 4 percent red mud, 2 percent graphite and 6 percent of red mud are prepared. Bar castings are cut into cylindrical discs of 20mm diameter and 20mm thickness. Corrosion tests were conducted at room temperature (230 °C) using conventional weight loss method according to ASTM G69-80. The corrodents used for the test were hydrochloric acid solution of different concentrations. Specimens were tested for every 24 hours interval up to 96 hours. Four specimens for each condition and time were immersed in corrodent. In each case the corrosion rate decreases with increase in exposure time for matrix and metal matrix composites whatever may be the concentration of hydrochloric acid. This may be due to aluminium, which may induce passivation due to development of non-porous layer. As red mud content increases the composites become corrosion resistant due to insulating nature of ceramic material red mud and less exposure of matrix alloy in those metal matrix composites.

Keywords: Al6061, graphite, passivation, red mud, vortex

Procedia PDF Downloads 527

Authors: Chia-Ching Tsai

Abstract:

In service delivery, interpersonal interaction is the key to customer satisfaction, and apparently, the factor of human is critical in service delivery. Besides, customers quite care about the consequences of co-recovery. Thus, this research focuses on service failure caused by other customers and uses a 2x2 factorial design to investigate the impact of consequence and level of service co-recovery on post-recovery satisfaction and repurchase intent. 150 undergraduates were recruited as participants, and assigned to one of the four cells randomly. Every participant was requested to read the scenario and then rated the post-recovery satisfaction and repurchase intent. The results show that under the condition of failed co-recovery, level of co-recovery has no effect on post-recovery satisfaction, while under the condition of successful co-recovery, high-level co-recovery causes significantly higher post-recovery satisfaction than low-level co-recovery. Moreover, post-recovery satisfaction has significantly positive impact on repurchase intent. In the system of service delivery, customers interact with other customers frequently. Therefore, comparing with the literature, this research focuses on the service failure caused by other customers. This research also supplies a better understanding of customers’ view on consequences of different levels of co-recovery, which is helpful for the practitioners to make use of co-recovery.

Keywords: service failure, service co-recovery, consequence of co-recovery, level of co-recovery, post-recovery satisfaction, repurchase intent

Procedia PDF Downloads 405

Authors: Said Rabah Azzam, Andrew Graham

Abstract:

Fragmentation of packets caused by encryption applied on the network layer of the IOS model in Internet Protocol version 4 (IPv4) networks as well as the possibility of using fragmentation and Access Control Lists (ACLs) as a method of restricting network access to certain hosts or areas of a network.Using default settings, fragmentation is expected to occur and each fragment to be reassembled at the other end. If this does not occur then a high number of ICMP messages should be generated back towards the source host indicating that the packet is too large and that it needs to be made smaller. This result is also expected when the MTU is changed for certain links between devices.When using ACLs and packet fragments to restrict access to hosts or network segments it is possible that ACLs cannot be set up in this way. If ACLs cannot be setup to allow only fragments then it is a limitation of the hardware’s firmware holding back this particular method. If the ACL on the restricted switch can be set up in such a way to allow only fragments then a connection that forces packets to fragment should be allowed to pass through the ACL. This should then make a network connection to the destination machine allowing data to be sent to and from the destination machine. ICMP messages from the restricted access switch and host should also be blocked from being sent back across the link which will be shown in an SSH session into the switch.

Keywords: fragmentation, encryption, security, switch

Procedia PDF Downloads 314

Authors: Christina Surmei

Abstract:

Autism Spectrum Disorder (ASD) is defined as a diverse range of developmental conditions that affect an individual’s functionality. ASD is not linear, and individuals can present with deficits in social interaction, communication, and demonstrate limited, repetitive patterns of behaviour, interests, or activities. These characteristics may be observed in a variety of ways and range from mild to severe. ASD may include autism disorder, pervasive developmental disorder not otherwise specified, Asperger’s, or other related pervasive developmental disorders. Modern slavery is defined as 'situations of exploitation that a person cannot refuse or leave because of threats, violence, coercion, and abuse of power or deception'. A review of the literature investigated the prevalence of research regarding ASD and modern slavery. Two universal search engines and five online journals were used as the apparatuses of inquiry. The results revealed two editorials, one study, and one act, totaling four publications attesting to ASD and modern slavery as a joint entity. This is representative of a vast absence of research. However, as individual entities research on autism and modern slavery is in a general high occurrence. This paper has identified a significant gap in research on ASD and modern slavery, and initiates the dialogue to unpack a significant global issue in society today.

Keywords: autism spectrum, education, modern slavery, support

Procedia PDF Downloads 153

Authors: Kianoosh Samimi, Farhad Estakhr, Mahdi Mahdikhani, Faramaz Moodi

Abstract:

The self-consolidating concrete (SCC) performance over ordinary concrete is generally related to the ingredients used. The metakaolin can modify various properties of concrete, due to high pozzolanic reactions and also makes a denser microstructure. The objective of this paper is to examine the influence of three types of Portland cement and metakaolin on compressive strength and transport properties of SCC at early ages and up to 90 days. Six concrete mixtures were prepared with three types of different cements and substitution of 15% metakaolin. The results show that the highest value of compressive strength was achieved for Portland Slag Cement (PSC) and without any metakaolin at age of 90 days. Conversely, the lowest level of compressive strength at all ages of conservation was obtained for Pozzolanic Portland Cement (PPC) and containing 15% metakaolin. As can be seen in the results, compressive strength in SCC containing Portland cement type II with metakaolin is higher compared to that relative to SCC without metakaolin from 28 days of age. On the other hand, the samples containing PSC and PPC with metakaolin had a lower compressive strength than the plain samples. Therefore, it can be concluded that metakaolin has a negative effect on the compressive strength of SCC containing PSC and PPC. In addition, results show that metakaolin has enhanced chloride durability of SCCs and reduced capillary water absorption at 28, 90 days.

Keywords: SCC, metakaolin, cement type, compressive strength, chloride diffusion

Procedia PDF Downloads 207