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Authors: F. Asadi, M. M. Zerafat, S. Sabbaghi

Abstract:

Among water pollutants, volatile organic compounds can cause severe long lasting effects not only on biotic organism but also on human health. As a result, this material group has attracted more attention in recent years. Adsorption is one of the common processes for remediation of aromatic compounds. In this study, porous clay hetrostructers (PCHs) are synthesized through gallery template approach and cetyltrimethylammonium bromide and dodecylamine used as template and co-template, respectively. Porous clay is characterized by XRD and FTIR. Batch adsorption experiments were carried out to investigate the effect of various adsorption parameters like adsorbent dosage, pH, initial concentration and contact time. It was found that by increasing adsorbent dosage from 0.5gr/lit to 4gr/lit, toluene removal is increased from 34% to 88.1%. Increasing contact time and decreasing the pH of aqueous solution increases toluene removal efficiency.

Keywords: adsorption, clay, nano-porous, toluene

Procedia PDF Downloads 338

Authors: Abdi Ammar, Ouazir Youcef, Laissaoui Abdelmalek

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In this work, an approach based on transmission lines theory is presented. It is exploited for the calculation of overvoltage created by direct impacts of lightning waves on a guard cable of an overhead high-voltage line. First, we show the theoretical developments leading to the propagation equation, its discretization by finite difference time domain method (FDTD), and the resulting linear algebraic equations, followed by the calculation of the linear parameters of the line. The second step consists of solving the transmission lines system of equations by the FDTD method. This enabled us to determine the spatio-temporal evolution of the induced overvoltage.

Keywords: lightning surge, transient overvoltage, eddy current, FDTD, electromagnetic compatibility, ground wire

Procedia PDF Downloads 83

Authors: Rihab Hamdi, Amel Hadri Hamida, Ouafae Bennis, Sakina Zerouali

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This paper features a performance analysis and robustness assessment of a digitally controlled DC-DC three-cell buck converter associated in parallel, operating in continuous conduction mode (CCM), facing feeding parameters variation and loads disturbance. The control strategy relies on the continuous-time with an averaged modeling technique for high-frequency switching converter. The methodology is to modulate the complete design procedure, in regard to the existence of an instantaneous current operating point for designing the digital closed-loop, to the same continuous-time domain. Moreover, the adopted approach is to include a digital voltage control (DVC) technique, taking an account for digital control delays and sampling effects, which aims at improving efficiency and dynamic response and preventing generally undesired phenomena. The results obtained under load change, input change, and reference change clearly demonstrates an excellent dynamic response of the proposed technique, also as provide stability in any operating conditions, the effectiveness is fast with a smooth tracking of the specified output voltage. Simulations studies in MATLAB/Simulink environment are performed to verify the concept.

Keywords: continuous conduction mode, digital control, parallel multi-cells converter, performance analysis, power electronics

Procedia PDF Downloads 150

Authors: Rajesh Kumar Meena, Suman Jhajharia, Goutam Chakraborty

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Plasmonic silver nanoparticles (Ag NPs) was synthesized by chemical reduction method using Trachyspermum Ammi (TA, Ajwain) seeds extract in aqueous medium and AgNO3 solution at different time interval. Reaction time, and concentration of AgNO3 and TA could accelerate the reduction rate of Ag+ and affect AgNPs size and concentration of NPs. Surface plasmon resonance band centered at 420-430 nm (88.78nm) was recognised as first exitonic peak of UV-Vis absorption spectra of AgNPs that used to calculate the particle size (10-30 nm). FTIR results TA supported AgNPs showed decrease in intensity of peaks at 3394, 1716 and 1618 cm-1 with respect to the plain TA indicating the involvement of O-H, carbonyl group and C=C stretching in formation of TA-AgNPs aggregates. The C-O-C and C-N stretching suggested the presence of many phytochemicals on the surface of the NPs. Impedance study reveals that at low concentration of TA the rate of charge transfer is in TA-AgNPs aggregates, found higher than the higher TA concentration condition that confirms the stability of AgNPs in water. Extract reduce silver ions into silver nanoparticles (NPs) of size 6-50nm. Pronounce effect of the time on Ag NPs concentration and particle size, was exhibited by the system These biogenic Ag NPs are characterized using UV- Vis spectrophotometry (UV-Visible), Fourier transformation infrared (FTIR) and XRD. These studies give us inside view of the most probable mechanism of biosynthesis and optoelectronic properties of the as synthesised Ag NPs.

Keywords: antimicrobial activity, bioreduction, capping agent, silver nanoparticles

Procedia PDF Downloads 326

Authors: Pham-Thi Huong, Byeong-Kyu Lee, Jitae Kim, Chi-Hyeon Lee

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Fe-nano zeolite adsorbent was used for removal of Ni (II) ions from aqueous solution. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and the surface area Brunauer–Emmett–Teller (BET) using for analysis of functional groups, morphology and surface area. Bath adsorption experiments were analyzed on the effect of pH, time, adsorbent doses and initial Ni (II) concentration. The optimum pH for Ni (II) removal using Fe-nano zeolite was found at 5.0 and 90 min of reaction time. The maximum adsorption capacity of Ni (II) was 231.68 mg/g based on the Langmuir isotherm. The kinetics data for the adsorption process was fitted with the pseudo-second-order model. The desorption of Ni (II) from Ni-loaded Fe-nano zeolite was analyzed and even after 10 cycles 72 % desorption was achieved. These finding supported that Fe-nano zeolite with high adsorption capacity, high reuse ability would be utilized for Ni (II) removal from water.

Keywords: Fe-nano zeolite, adsorption, Ni (II) removal, regeneration

Procedia PDF Downloads 232

Authors: Manop Aorpimai, Ponthep Navakitkanok

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In this paper, the development of the ephemeris generation module used for the Thaichote satellite operations is presented. It is a vital part of the flight dynamics system, which comprises, the orbit determination, orbit propagation, event prediction and station-keeping maneuver modules. In the generation of the spacecraft ephemeris data, the estimated orbital state vector from the orbit determination module is used as an initial condition. The equations of motion are then integrated forward in time to predict the satellite states. The higher geopotential harmonics, as well as other disturbing forces, are taken into account to resemble the environment in low-earth orbit. Using a highly accurate numerical integrator based on the Burlish-Stoer algorithm the ephemeris data can be generated for long-term predictions, by using a relatively small computation burden and short calculation time. Some events occurring during the prediction course that are related to the mission operations, such as the satellite’s rise/set viewed from the ground station, Earth and Moon eclipses, the drift in ground track as well as the drift in the local solar time of the orbital plane are all detected and reported. When combined with other modules to form a flight dynamics system, this application is aimed to be applied for the Thaichote satellite and successive Thailand’s Earth-observation missions.

Keywords: flight dynamics system, orbit propagation, satellite ephemeris, Thailand’s Earth Observation Satellite

Procedia PDF Downloads 377

Authors: Andreas Gohs, Reinhold Kosfeld

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This study should be of interest for practitioners who want to predict precisely the sales numbers of vehicles equipped with an innovative propulsion technology as well as for researchers interested in applied (regional) time series analysis. The study is based on the numbers of new registrations of pure electric and hybrid cars. Methods of time series analysis like ARIMA are compared with the Bass Diffusion-model concerning their forecasting performances for new registrations in Germany at the national and federal state levels. Especially it is investigated if the additional information content from regional data increases the forecasting accuracy for the national level by adding predictions for the federal states. Results of parameters of the Bass Diffusion Model estimated for Germany and its sixteen federal states are reported. While the focus of this research is on the German market, estimation results are also provided for selected European and other countries. Concerning Bass-parameters and forecasting performances, we get very different results for Germany's federal states and the member states of the European Union. This corresponds to differences across the EU-member states in the adoption process of this innovative technology. Concerning the German market, the adoption is rather proceeded in southern Germany and stays behind in Eastern Germany except for Berlin.

Keywords: bass diffusion model, electric vehicles, forecasting performance, market diffusion

Procedia PDF Downloads 168

Authors: Young-Hyun Seo, Hosuk Shin, Eun-Hak Lee, Seung-Young Kho

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This study analyzed and visualized the rental and return data of the public bike sharing system in Seoul, Ttareungyi, from September 2015 to October 2017. With the surge of system users, the number of times of collection and distribution in 2017 increased by three times compared to 2016. The city plans to deploy about 20,000 public bicycles by the end of 2017 to expand the system. Based on about 3.3 million historical data, we calculated the average trip time and the number of trips from one station to another station. The mobility patterns between stations are graphically displayed using R and Tableau. Demand for public bike sharing system is heavily influenced by day and weather. As a result of plotting the number of rentals and returns of some stations on weekdays and weekends at intervals of one hour, there was a difference in rental patterns. As a result of analysis of the rental and return patterns by time of day, there were a lot of returns at the morning peak and more rentals at the afternoon peak at the center of the city. It means that stock of bikes varies largely in the time zone and public bikes should be rebalanced timely. The result of this study can be applied as a primary data to construct the demand forecasting function of the station when establishing the rebalancing strategy of the public bicycle.

Keywords: demand forecasting, mobility patterns, public bike sharing system, visualization

Procedia PDF Downloads 190

Authors: A. Pirestani, M. Alirezaie, S. Safavipour

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The present study was designed to investigate the effect of dietary canola oil and Vit E on sperm motility parameters. Sixteen Kurdish rams were selected with weight average 54.47±2.58 and with year of 3 to 4 approximately and divided to four experimental groups as randomly. Experimental groups were control, Vit E (20 IU in diet), canola oil (2.5% of DMI) and Vit E (20 IU in diet) + Canola oil (2.5% of DMI). Sperm was collected by electroejaculation at 6 week and 11 week after begging of experiment and sperm motility was analyzed by using CASA software. The results showed that motility parameter wasn’t significant difference between whole experimental groups at first time (week 6) but PM% and TM% was significant difference in canola oil and Vit E at second time (week 11), separately. It was concluded that Vit E and canola oil improvement sperm motility in Kurdish ram. The present study was designed to investigate the effect of dietary canola oil and Vit E on sperm motility parameters. Sixteen Kurdish rams were selected with weight average 54.47±2.58 and with year of 3 to 4 approximately and divided to four experimental groups as randomly. Experimental groups were control, Vit E (20 IU in diet), canola oil (2.5% of DMI) and Vit E (20 IU in diet) + Canola oil (2.5% of DMI). Sperm was collected by electroejaculation at 6 week and 11 week after begging of experiment and sperm motility was analyzed by using CASA software. The results showed that motility parameter was not significant difference between whole experimental groups at first time (week 6) but PM% and TM% was significant difference in canola oil and Vit E at second time (week 11), separately. It was concluded that Vit E and canola oil improvement sperm motility in Kurdish ram. The present study was designed to investigate the effect of dietary canola oil and Vit E on sperm motility parameters. Sixteen Kurdish rams were selected with weight average 54.47±2.58 and with year of 3 to 4 approximately and divided to four experimental groups as randomly. Experimental groups were control, Vit E (20 IU in diet), canola oil (2.5% of DMI) and Vit E (20 IU in diet) + Canola oil (2.5% of DMI). Sperm was collected by electroejaculation at 6 week and 11 week after begging of experiment and sperm motility was analyzed by using CASA software. The results showed that motility parameter wasn’t significant difference between whole experimental groups at first time (week 6) but PM% and TM% was significant difference in canola oil and Vit E at second time (week 11), separately. It was concluded that Vit E and canola oil improvement sperm motility in Kurdish ram. The present study was designed to investigate the effect of dietary canola oil and Vit E on sperm motility parameters. Sixteen Kurdish rams were selected with weight average 54.47±2.58 and with year of 3 to 4 approximately and divided to four experimental groups as randomly. Experimental groups were control, Vit E (20 IU in diet), canola oil (2.5% of DMI) and Vit E (20 IU in diet) + Canola oil (2.5% of DMI). Sperm was collected by electroejaculation at 6 week and 11 week after begging of experiment and sperm motility was analyzed by using CASA software. The results showed that motility parameter wasn’t significant difference between whole experimental groups at first time (week 6) but PM% and TM% was significant difference in canola oil and Vit E at second time (week 11), separately. It was concluded that Vit E and canola oil improvement sperm motility in Kurdish ram.

Keywords: canola oil, motility, ram, sperm, Vit E

Procedia PDF Downloads 641

Authors: Faisal Alsaaq

Abstract:

Hydrographic surveys have traditionally relied on the availability of tide information for the reduction of sounding observations to a common datum. In most cases, tide information is obtained from tide gauge observations and/or tide predictions over space and time using local, regional or global tide models. While the latter often provides a rather crude approximation, the former relies on tide gauge stations that are spatially restricted, and often have sparse and limited distribution. A more recent method that is increasingly being used is Global Navigation Satellite System (GNSS) positioning which can be utilised to monitor height variations of a vessel or buoy, thus providing information on sea level variations during the time of a hydrographic survey. However, GNSS heights obtained under the dynamic environment of a survey vessel are affected by “non-tidal” processes such as wave activity and the attitude of the vessel (roll, pitch, heave and dynamic draft). This research seeks to examine techniques that separate the tide signal from other non-tidal signals that may be contained in GNSS heights. This requires an investigation of the processes involved and their temporal, spectral and stochastic properties in order to apply suitable recovery techniques of tide information. In addition, different post-mission and near real-time GNSS positioning techniques will be investigated with focus on estimation of height at ocean. Furthermore, the study will investigate the possibility to transfer the chart datums at the location of tide gauges.

Keywords: hydrography, GNSS, datum, tide gauge

Procedia PDF Downloads 265

Authors: Muhammad Yusuf Abduh, Syaripudin, Laksmitha Dyanie, Robert Manurung

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The time profile of moisture content for different fractions (PT-3, PT-7, PT-14, NPT-21) of trisperma seeds (Reutealis trisperma) was determined at a relative humidity of 67% and 27°C for a four months period. The diffusion coefficient of water in the trisperma seeds was determined using an analytical solution of instationary diffusion equation and used to model the moisture content in the seeds. The total oil content of the seeds and the acid value of the extracted oil from the stored seeds were periodically measured for four months. The acid value of the extracted oil from the stored seeds increased for all conditions (1.1 to 2.8 mg KOH/g for PT-3, 1.9 to 9.9 mg KOH/g for PT-7, 3.4 to 11.6 mg KOH/g for PT-14 and 4.7 to 25.4 mg KOH/g for NPT-21). The acid value of trisperma oil and biodiesel that has been stored for four months (27°C, closed container) was also determined. Upon storage, the acid value of trisperma oil and biodiesel only slightly increased from 1.1 to 1.3 mg KOH/g and 0.4 to 0.43 mg KOH/g, respectively.

Keywords: acid value, biodiesel, moisture content, Reutealis trisperma, storage

Procedia PDF Downloads 290

Authors: Camila Plaza, Stefan Felder

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In October 2014, the TARMED reform was implemented in Switzerland. In an effort to even out the financial standing of general practitioners (including pediatricians) relative to that of specialists in the outpatient sector, the reform tackled two aspects: on the one hand, GPs would be able to bill an additional 9 CHF per patient, once per consult per day. This is referred to as the surcharge position. As a second measure, it reduced the fees for certain technical services targeted to specialists (e.g., imaging, surgical technical procedures, etc.). Given the fee-for-service reimbursement system in Switzerland, we predict that physicians reacted to the economic incentives of the reform by increasing the consults per patient and decreasing the average amount of time per consult. Within this framework, our treatment group is formed by GPs and our control group by those specialists who were not affected by the reform. Using monthly insurance claims panel data aggregated at the physician praxis level (provided by SASIS AG), for the period of January 2013-December 2015, we run difference in difference panel data models with physician and time fixed effects in order to test for the causal effects of the reform. We account for seasonality, and control for physician characteristics such as age, gender, specialty, and physician experience. Furthermore, we run the models on subgroups of physicians within our sample so as to account for heterogeneity and treatment intensities. Preliminary results support our hypothesis. We find evidence of an increase in consults per patients and a decrease in time per consult. Robustness checks do not significantly alter the results for our outcome variable of consults per patient. However, we do find a smaller effect of the reform for time per consult. Thus, the results of this paper could provide policymakers a better understanding of physician behavior and their sensitivity to financial incentives of reforms (both past and future) under the current reimbursement system.

Keywords: difference in differences, financial incentives, health reform, physician behavior

Procedia PDF Downloads 128

Authors: Shehzad Khan, Jehangir Khan, Shah Babar, Rashid Mahmood, Rizwan Khan, Sanya Hadi

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Ascaris lumbricoides are familiar with the roundworm that causes biliary infections in humans. Nevertheless, ascariasis is primarily found in the jejunum and transferred in numerous body parts with the intake of Ascaris lumbricoides present in food and water. These study methods were implemented at the Saidu Teaching Hospital Radiology Department from December 2021 to January 2023. This study includes the participants suffering from biliary ascariasis admitted or visited Saidu Teaching Hospital in that time frame. Clinical assessment of the participants was done based on the appearance of signs and symptoms present in them. The participant's laboratory test was done to determine the level of basic body parameters. After that ultrasonography was used to diagnose the presence and appearance of worms. Endoscopic retrograde cholangiopancreatography (ERCP) was used to extract worms from biliary channels, and the incidence of post-ERCP biliary ascariasis was accessed with ultrasonography. This study's results show the presence of numerous types of worms in the biliary channels of patients. Also, the level of body parameters, for instance, neutrophil, hemoglobin, and others, were compared at the time of admission and at the time of discharge from the hospital. Furthermore, the incidence of post-ERCP biliary ascariasis was reported as 4% in females, and 1% in males, respectively.

Keywords: Ascaris, biliary, ERCP, ultrasound

Procedia PDF Downloads 101

Authors: G. Kabir, A. M. Mohammed, M. A. Bawa

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The paper presents corrosion behaviors of Naval Brass, aluminum alloy and carbon steel in simulated seawater under stagnant conditions. The behaviors were characterized on the variation of chloride ions concentration in the range of 3.0wt% and 3.5wt% and exposure time. The weight loss coupon-method immersion technique was employed. The weight loss for the various alloys was measured. Based on the obtained results, the corrosion rate was determined. It was found that the corrosion rates of the various alloys are related to the chloride ions concentrations, exposure time and kinetics of passive film formation of the various alloys. Carbon steel, suffers corrosion many folds more than Naval Brass. This indicated that the alloy exhibited relatively strong resistance to corrosion in the exposure environment of the seawater. Whereas, the aluminum alloy exhibited an excellent and beneficial resistance to corrosion more than the Naval Brass studied. Despite the prohibitive cost, Naval Brass and aluminum alloy, indicated to have beneficial corrosion behavior that can offer wide range of application in seashore operations. The corrosion kinetics parameters indicated that the corrosion reaction is limited by diffusion mass transfer of the corrosion reaction elements and not by reaction controlled.

Keywords: alloys, chloride ions concentration, corrosion kinetics, corrosion rate, diffusion mass transfer, exposure time, seawater, weight loss

Procedia PDF Downloads 302

Authors: Bernard Polednik, Adam Piotrowicz, Lukasz Guz, Marzenna Dudzinska

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Transportation is considered to be responsible for increased exposure of road users – i.e., drivers, car passengers, and pedestrians as well as inhabitants of houses located near roads - to pollutants emitted from vehicles. Accurate estimates are, however, difficult as exposure depends on many factors such as traffic intensity or type of fuel as well as the topography and the built-up area around the individual routes. The season and weather conditions are also of importance. In the case of inhabitants of houses located near roads, their exposure depends on the distance from the road, window tightness and other factors that decrease pollutant infiltration. This work reports the variations of particle concentrations along a selected road in Lublin, Poland. Their impact on the exposure for road users as well as for inhabitants of houses located near the road is also presented. Mobile and fixed-site measurements were carried out in peak (around 8 a.m. and 4 p.m.) and off-peak (12 a.m., 4 a.m., and 12 p.m.) traffic times in all 4 seasons. Fixed-site measurements were performed in 12 measurement points along the route. The number and mass concentration of particles was determined with the use of P-Trak model 8525, OPS 3330, DustTrak DRX model 8533 (TSI Inc. USA) and Grimm Aerosol Spectrometer 1.109 with Nano Sizer 1.321 (Grimm Aerosol Germany). The obtained results indicated that the highest concentrations of traffic-related pollution were measured near 4-way traffic intersections during peak hours in the autumn and winter. The highest average number concentration of ultrafine particles (PN0.1), and mass concentration of fine particles (PM2.5) in fixed-site measurements were obtained in the autumn and amounted to 23.6 ± 9.2×10³ pt/cm³ and 135.1 ± 11.3 µg/m³, respectively. The highest average number concentration of submicrometer particles (PN1) was measured in the winter and amounted to 68 ± 26.8×10³ pt/cm³. The estimated doses of particles deposited in the commuters’ and pedestrians’ lungs within an hour near 4-way TIs in peak hours in the summer amounted to 4.3 ± 3.3×10⁹ pt/h (PN0.1) and 2.9 ± 1.4 µg/h (PM2.5) and 3.9 ± 1.1×10⁹ pt/h (PN0.1) or 2.5 ± 0.4 µg/h (PM2.5), respectively. While estimating the doses inhaled by the inhabitants of premises located near the road one should take into account different fractional penetration of particles from outdoors to indoors. Such doses assessed for the autumn and winter are up to twice as high as the doses inhaled by commuters and pedestrians in the summer. In the winter traffic-related ultrafine particles account for over 70% of all ultrafine particles deposited in the pedestrians’ lungs. The share of traffic-related PM10 particles was estimated at approximately 33.5%. Concluding, the results of the particle concentration measurements along a road in Lublin indicated that the concentration is mainly affected by the traffic intensity and weather conditions. Further detailed research should focus on how the season and the metrological conditions affect concentration levels of traffic-related pollutants and the exposure of commuters and pedestrians as well as the inhabitants of houses located near traffic routes.

Keywords: air quality, deposition dose, health effects, vehicle emissions

Procedia PDF Downloads 95

Authors: Muhammad Alif Bin Razali, Cheng-Gang Xie, Wai Lam Loh

Abstract:

A venturi device is commonly used as an integral part of a multiphase flowmeter (MPFM) in real-time oil-gas production monitoring. For an accurate determination of individual phase fraction and flowrate, a gas-liquid flow ideally needs to be well mixed in the venturi measurement section. Partial flow mixing is achieved by installing a venturi vertically downstream of the blind-tee pipework that ‘homogenizes’ the incoming horizontal gas-liquid flow. In order to study in-depth the flow-mixing effect of the blind-tee, gas-liquid flows are captured at blind-tee and venturi sections by using a high-speed video camera and a purpose-built transparent test rig, over a wide range of superficial liquid velocities (0.3 to 2.4m/s) and gas volume fractions (10 to 95%). Electrical capacitance sensors are built to measure the instantaneous holdup (of oil-gas flows) at the venturi inlet and throat. Flow regimes and flow (a)symmetry are investigated based on analyzing the statistical features of capacitance sensors’ holdup time-series data and of the high-speed video time-stacked images. The perceived homogenization effect of the blind-tee on the incoming intermittent horizontal flow regimes is found to be relatively small across the tested flow conditions. A horizontal (blind-tee) to vertical (venturi) flow-pattern transition map is proposed based on gas and liquid mass fluxes (weighted by the Baker parameters).

Keywords: blind-tee, flow visualization, gas-liquid two-phase flow, MPFM

Procedia PDF Downloads 128

Authors: So-Young Ju, Sung-Mi Jo, Eui-Rim Jeong

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In this paper, based on the conventional single carrier frequency domain equalization (SC-FDE) structure, we propose a new SC-FDE structure to cope with narrowband jammer. In the conventional SC-FDE structure, channel estimation is performed in the time domain. When a narrowband jammer exists, time-domain channel estimation is very difficult due to high power jamming interference, which degrades receiver performance. To relieve from this problem, a new SC-FDE frame is proposed to enable channel estimation under narrow band jamming environments. In this paper, we proposed a modified SC-FDE structure that can perform channel estimation in the frequency domain and verified the performance via computer simulation.

Keywords: channel estimation, jammer, pilot, SC-FDE

Procedia PDF Downloads 475

Authors: Wesley H. Brewer, John C. Sanford

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SciPaaS is a prototype development of an execution platform/middleware designed to make it easy for scientists to rapidly deploy their scientific applications (apps) to the cloud. It provides all the necessary infrastructure for running typical IXP (Input-eXecute-Plot) style apps, including: a web interface, post-processing and plotting capabilities, job scheduling, real-time monitoring of running jobs, and even a file/case manager. In this paper, first the system architecture is described and then is demonstrated for a two scientific applications: (1) a simple finite-difference solver of the inviscid Burger’s equation, and (2) Mendel’s Accountant—a forward-time population genetics simulation model. The implications of the prototype are discussed in terms of ease-of-use and deployment options, especially in cloud environments.

Keywords: web-based simulation, cloud computing, Platform-as-a-Service (PaaS), rapid application development (RAD), population genetics

Procedia PDF Downloads 590

Authors: Yuri Boiko, Ci Lin, Iluju Kiringa, Tet Yeap

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The performance of a BLDC motor controlled by the Kalman filter-based position-sensorless drive is studied in terms of its dependence on the system’s parameters' variations. The effects of system’s parameters changes on the dynamic behavior of state variables are verified. Simulated is a closed-loop control scheme with a Kalman filter in the feedback line. Distinguished are two separate data sampling modes in analyzing feedback output from the BLDC motor: (1) equal angular separation and (2) equal time intervals. In case (1), the data are collected via equal intervals Δθ of rotor’s angular position θᵢ, i.e., keeping Δθ=const. In case (2), the data collection time points tᵢ are separated by equal sampling time intervals Δt=const. Demonstrated are the effects of the parameters changes on the sensorless control flow, in particular, reduction of the torque ripples, switching spikes, torque load balancing. It is specifically shown that an efficient suppression of commutation induced torque ripples is achievable selection of the sampling rate in the Kalman filter settings above certain critical value. The computational cost of such suppression is shown to be higher for the motors with lower induction values of the windings.

Keywords: BLDC motor, Kalman filter, sensorless drive, state variables, torque ripples reduction, sampling rate

Procedia PDF Downloads 148

Authors: Ji Chan Kim, Seok Hong Min, Tae Kwon Ha

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Effect of boron addition on the microstructure and mechanical properties of AZ91D Mg alloy was investigated in this study. Through calculation of phase equilibria, carried out by using FactSage® and FTLite database, solution treatment temperature was decided as 420 °C where supersaturated solid solution can be obtained. Solid solution treatment was conducted at 420 °C for 24 hrs followed by hot rolling at 420 °C and the total reduction was about 60%. Recrystallization heat treatment was followed at 420 °C for 6 hrs to obtain equiaxed microstructure. After recrystallization treatment, aging heat treatment was conducted at temperature of 200 °C for time intervals from 1 min to 200 hrs and hardness of each condition was measured by micro-Vickers method. Peak hardness was observed after 20 hrs. Tensile tests were also conducted on the specimens aged for various time intervals and the results were compared with hardness.

Keywords: AZ91D Mg alloy, boron, heat treatment, microstructure, mechanical properties, hardness

Procedia PDF Downloads 316

Authors: Radia Chemlal, Salim Mehenni, Dahbia Leila Anes-boulahbal, Mohamed Kherat, Nabil Mameri

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The application of the electric field is considered to be a very promising method in cancer therapy. Indeed, cancer cells are very sensitive to the electric field, although the cellular response is not entirely clear. The tests carried out consisted in subjecting the RD cell line under the effect of the continuous electric field while varying certain parameters (voltage, exposure time, and cell concentration). The response surface methodology (RSM) was used to assess the effect of the chosen parameters, as well as the existence of interactions between them. The results obtained showed that the voltage, the cell concentration as well as the interaction between voltage and exposure time have an influence on the mortality rate of the RD cell line.

Keywords: continuous electric field, RD cancer cell line, RSM, voltage

Procedia PDF Downloads 113

Authors: Nouby Ghazaly

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The present paper investigates experimentally the effect coefficient of friction at different operation conditions on the variation of the brake temperature, brake force, and brake vibration with the braking time. All the experimental tests were carried out using brake dynamometer which designed and constructed in Vehicle Dynamic Laboratory. The results indicate that the brake temperature increases with the increase of the normal force and sliding speed especially with the increase of the braking time. The normal force has the effect on increasing the brake force. On the contrary, the vehicle speed has the effect on decreasing the brake force. Both the normal force and sliding speed affect the brake vibration according to the friction behavior.

Keywords: brake dynamometer, coefficient of friction, drum brake vibrations, friction behavior

Procedia PDF Downloads 311

Authors: Fares Hedayatit, Arnauld Joly, Panagiotis Papadimitriou

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Many machine learning tasks such as text annotation usually require training over very big datasets, e.g., millions of web documents, that can be represented in a sparse input space. State-of the-art tree-based ensemble algorithms cannot scale to such datasets, since they include operations whose running time is a function of the input space size rather than a function of the non-zero input elements. In this paper, we propose an efficient splitting algorithm to leverage input sparsity within decision tree methods. Our algorithm improves training time over sparse datasets by more than two orders of magnitude and it has been incorporated in the current version of scikit-learn.org, the most popular open source Python machine learning library.

Keywords: big data, sparsely representable data, tree-based models, scalable learning

Procedia PDF Downloads 263

Authors: Kathleen Cooney, Jennifer Coates, Lesley Leach, Kristin Hrenchir

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The objective of this retrospective study was to determine whether intrarenal injection of pentobarbital sodium is a practicable method of euthanasia in client-owned cats. 131 Cats were anesthetized using a combination of tiletamine, zolazepam, and acepromazine given by of subcutaneous or intramuscular injection. Once an appropriate plane of anesthesia was reached, 6 ml of pentobarbital sodium was injected into either the left or right kidney. The patient’s age, sex, estimated weight, presenting condition, estimated dehydration level, palpable characteristics of the kidney pre and post injection, physical response of the cat, and time to cardiopulmonary arrest were recorded. Analysis of 131 records revealed that cats receiving an intrarenal injection of pentobarbital sodium had an average time to cardiopulmonary arrest of 1 minute. The great majority (79%) experienced cardiopulmonary arrest in less than one minute with the remainder experiencing cardiopulmonary arrest between 1 and 8 minutes of the injection. 95% of cats had no observable reaction to intrarenal injection other than cardiopulmonary arrest. In the 19% of cases where kidney swelling was not palpable upon injection, average time to cardiopulmonary arrest increased from 0.9 to 1.6 min. Conclusions and Clinical Relevance: Intrarenal injections of pentobarbital sodium are similar in effect to intravenous methods of euthanasia. Veterinarians who elect to use intrarenal injections can expect cardiopulmonary arrest to occur quickly in the majority of patients with few agonal reactions. Intrarenal injection of pentobarbital sodium in anesthetized cats has ideally suited for cases of owner observed euthanasia when obtaining intravenous access would difficult or disruptive.

Keywords: euthanasia, injection, intrarenal, pentobarbital sodium

Procedia PDF Downloads 343

Authors: Shazalina Mat Zin, Ahmad Abd. Majid, Ahmad Izani Md. Ismail, Muhammad Abbas

Abstract:

The generalized wave equation models various problems in sciences and engineering. In this paper, a new three-time level implicit approach based on cubic trigonometric B-spline for the approximate solution of wave equation is developed. The usual finite difference approach is used to discretize the time derivative while cubic trigonometric B-spline is applied as an interpolating function in the space dimension. Von Neumann stability analysis is used to analyze the proposed method. Two problems are discussed to exhibit the feasibility and capability of the method. The absolute errors and maximum error are computed to assess the performance of the proposed method. The results were found to be in good agreement with known solutions and with existing schemes in literature.

Keywords: collocation method, cubic trigonometric B-spline, finite difference, wave equation

Procedia PDF Downloads 542

Authors: Y. Yılmaz, C. Ünal, A. Dursun

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Distribution channels play significant role for hotels. Direct and indirect selling options of hotel rooms have been increased especially with the help of new technologies, i.e. hotel’s own web sites and online booking sites. Although these options emerged as tools for diversifying the distribution channels, vast number of hotels -mostly resort hotels- is still heavily dependent upon international tour operators when selling their products. On the other hand, hotel sector is so vulnerable against crises. Economic, political or any other crisis can affect hotels very badly and so it is critical to have the right balance of distribution channel to avoid the adverse impacts of a crisis. In this study, it is aimed to search the impacts of a general crisis on the selling prices of hotels which have different weights of distribution channels. The study was done in Turkey where various crises occurred in 2015 and 2016 which had great negative impacts on Turkish tourism and led enormous occupancy rate and selling price reductions. 112 upscale resort hotel in Antalya, which is the most popular tourism destination of Turkey, joined to the research. According to the results, hotels with high dependency to international tour operators are more forced to reduce their room prices in crisis time compared to the ones which use their own web sites more. It was also found that the decline in room prices is limited for hotels which are working with national tour operators and travel agencies in crisis time.

Keywords: marketing channels, crisis, hotel, international tour operators, online travel agencies

Procedia PDF Downloads 320

Authors: Scott A. Abbott

Abstract:

This paper examines the increase in the occurrence of natural disasters worldwide and the need to support vulnerable communities in post-disaster recovery. Preparation and implementation of post-disaster recovery projects need to be improved to allow communities to recover infrastructure, housing, economically and socially following a catastrophe. With the continual rise in catastrophic events worldwide due to climate change, impacts on construction resources affect the ability for post-disaster recovery to be undertaken. This research focuses on case studies of catastrophic events in Queensland, Australia, to contribute to the body of knowledge and gain valuable insights on lessons learned from past events and how they have been managed. The aim of this research is to adopt qualitative data using semi-structured interviews from participants predominantly from the insurance sector to understand barriers that have previously and currently exist in post-disaster recovery. Existing literature was reviewed to reveal gaps in knowledge that needed to be tested. Qualitative data was collected and summarised from field research with the results analysed and discussed. Barriers that impacted post-disaster recovery included time, cost, and resource capability and capacity. Causal themes that impacted time and cost were identified as decision making, pre-planning, and preparedness, as well as effective communication across stakeholders. The research study applied a qualitative approach to the existing literature and case studies across Queensland, Australia, to identify existing and new barriers that impact post-disaster recovery. It was recommended to implement effective procurement strategies to assist in cost control; implement pre-planning and preparedness strategies across funder, contractor, and local governments; more effective and timely decision making to reduce time and cost impacts.

Keywords: construction recovery, cost, disaster recovery, resources, time

Procedia PDF Downloads 127

Authors: Mohammed Jourdani, Hamid Mounir, Abdellatif El Marjani

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Proton exchange membrane fuel cells (PEMFCs) have been developed as a promising power source for transportation and stationary applications, and power devices for computers and mobile telephones. This paper discusses and summarizes the latest developments of materials and remaining challenges of PEMFC. The different contributions to the material of all components and the efficiencies are analyzed. Many technical advances are introduced to increase the PEMFC fuel cell efficiency and life time for transportation, stationary and portable utilization. By the last years the total cost of this system is decreasing. However, the remaining challenges that need to be overcome mean that it will be several years before full commercialization can take place.

Keywords: PEMFC fuel cell, materials, recent development, efficiency, life time, commercialization possibility

Procedia PDF Downloads 311

Authors: Haya Salah, Srinivas Sharan

Abstract:

Healthcare facilities use appointment systems to schedule their appointments and to manage access to their medical services. With the growing demand for outpatient care, it is now imperative to manage physician's time effectively. However, high variation in consultation duration affects the clinical scheduler's ability to estimate the appointment duration and allocate provider time appropriately. Underestimating consultation times can lead to physician's burnout, misdiagnosis, and patient dissatisfaction. On the other hand, appointment durations that are longer than required lead to doctor idle time and fewer patient visits. Therefore, a good estimation of consultation duration has the potential to improve timely access to care, resource utilization, quality of care, and patient satisfaction. Although the literature on factors influencing consultation length abound, little work has done to predict it using based data-driven approaches. Therefore, this study aims to predict consultation duration using supervised machine learning algorithms (ML), which predicts an outcome variable (e.g., consultation) based on potential features that influence the outcome. In particular, ML algorithms learn from a historical dataset without explicitly being programmed and uncover the relationship between the features and outcome variable. A subset of the data used in this study has been obtained from the electronic medical records (EMR) of four different outpatient clinics located in central Pennsylvania, USA. Also, publicly available information on doctor's characteristics such as gender and experience has been extracted from online sources. This research develops three popular ML algorithms (deep learning, random forest, gradient boosting machine) to predict the treatment time required for a patient and conducts a comparative analysis of these algorithms with respect to predictive performance. The findings of this study indicate that ML algorithms have the potential to predict the provider service time with superior accuracy. While the current approach of experience-based appointment duration estimation adopted by the clinic resulted in a mean absolute percentage error of 25.8%, the Deep learning algorithm developed in this study yielded the best performance with a MAPE of 12.24%, followed by gradient boosting machine (13.26%) and random forests (14.71%). Besides, this research also identified the critical variables affecting consultation duration to be patient type (new vs. established), doctor's experience, zip code, appointment day, and doctor's specialty. Moreover, several practical insights are obtained based on the comparative analysis of the ML algorithms. The machine learning approach presented in this study can serve as a decision support tool and could be integrated into the appointment system for effectively managing patient scheduling.

Keywords: clinical decision support system, machine learning algorithms, patient scheduling, prediction models, provider service time

Procedia PDF Downloads 121

Authors: Stelios A. Mitilineos, Nicolas-Alexander Tatlas, Georgia Korompili, Lampros Kokkalas, Stelios M. Potirakis

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Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) is a widespread chronic disease that mostly remains undetected, mainly due to the fact that it is diagnosed via polysomnography which is a time and resource-intensive procedure. Screening the disease’s symptoms at home could be used as an alternative approach in order to alert individuals that potentially suffer from OSAHS without compromising their everyday routine. Since snoring is usually linked to OSAHS, developing a snore detector is appealing as an enabling technology for screening OSAHS at home using ubiquitous equipment like commodity microphones (included in, e.g., smartphones). In this context, this study developed a snore detection tool and herein present the approach and selection of specific sound features that discriminate snoring vs. environmental sounds, as well as the performance of the proposed tool. Furthermore, a Real-Time Snore Detector (RTSD) is built upon the snore detection tool and employed in whole-night sleep sound recordings resulting to a large dataset of snoring sound excerpts that are made freely available to the public. The RTSD may be used either as a stand-alone tool that offers insight to an individual’s sleep quality or as an independent component of OSAHS screening applications in future developments.

Keywords: obstructive sleep apnea hypopnea syndrome, apnea screening, snoring detection, machine learning, neural networks

Procedia PDF Downloads 207