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Modeling of Bending Behavior of IPMC Beams Using Concentrated Ion Boundary Layer
Waqas Akbar Lughmani,조재영,이장열,이계한 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.5
Ionic polymer metal composites (IPMCs) are an emerging class of electroactive polymers (EAP), which have many potential applications as sensors and actuators. Recently, IPMCs have been intensively studied because of their huge potential in medical, mechanical, electronic, and aerospace engineering. However, before the benefits of these materials can be effectively exploited for practical use, a mathematical model must be established to enhance understanding and predictability of IPMC actuation. The coupled electrical-chemical-mechanical response of an IPMC depends on the structure of the polyelectrolyte membrane, the morphology and conductivity of the metal electrodes, the cation properties, and the level of hydration. With this in mind, the purpose of this study is to establish a finite element model for bending behavior of IPMC beams. With reference to their operation principle, it is assumed that an IPMC beam has three virtual layers. We draw an analogy between thermal strain and real strain in IPMC due to volume change. This is a coupled structure/thermal model, and the finite element method is used to solve this model. The ion concentration distribution in the IPMC boundary layer is mimicked with the temperature distribution, and the electromechanical coupling coefficient is mimicked with the thermal expansion coefficient. Theoretical and experimental results demonstrate that our suggested model is practical and effective enough in predicting the blocking force of IPMC strips for different input voltages and strip thicknesses
Buffer-Based Adaptive Bitrate Algorithm for Streaming over HTTP
( Waqas Ur Rahman ),( Kwangsue Chung ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.11
Video streaming services make up a large proportion of Internet traffic on both fixed and mobile access throughout the world. Adaptive streaming allows for dynamical adaptation of the bitrate with varying network conditions, to guarantee the best user experience. Adaptive bitrate algorithms face a significant challenge in correctly estimating the throughput as it varies widely over time. In this paper, we first evaluate the throughput estimation techniques and show that the method that we have used offers stable response to throughput fluctuations while maintaining a stable playback buffer. Then, we propose an adaptive bitrate scheme that intelligently selects the video bitrates based on the estimated throughput and buffer occupancy. We show that the proposed scheme improves viewing experience by achieving a high video rate without taking unnecessary risks and by minimizing the frequency of changes in the video quality. Furthermore, we show that it offers a stable response to short-term fluctuations and responds swiftly to large fluctuations. We evaluate our algorithm for both constant bitrate (CBR) and variable bitrate (VBR) video content by taking into account the segment sizes and show that it significantly improves the quality of video streaming.
Effects of Alum and Ferric chloride as a Blend on Poultry Litter Characteristics
( Waqas Qasim ),( Byeong Eun Moon ),( Malinee Phonsuwan ),( Jin Seok Jo ),( Min Ho Lee ),( Mohammad Nafees ),( Hyeon Tae Kim ) 한국농업기계학회 2016 한국농업기계학회 학술발표논문집 Vol.21 No.2
Aluminum sulfate, Ferric chloride, Ferrous sulfate and Sodium bisulfate used on poultry litter in the past individually at different concentration to reduce environmental pollution and increase chicken productivity. Poultry litter is also rich in nutrients which can be used as a fertilizer to crops. In this study we evaluate the effects of Alum and Ferric chloride as a blend on poultry litter characteristics. There were total five treatments Control, T1, T2, T3 and T4. Five Boxes (70 × 40 × 43 cm) were used for this experiment, in each box 1 kg fresh chicken manure and 4 kg sawdust were mixed thoroughly. NH3 and CO₂ emission, pH, EC, Moisture content, Total and Water Soluble nutrients of poultry litter were determined after applying blend of Alum and ferric chloride to T1, T2, T3 and T4 at concentration of (5%+5%), (2.5%+5%), (5%+2.5%), and (2.5%+2.5%) of litter respectively. All the parameters except from nutrients were checked on weekly basis up to six weeks. Nutrients were checked after 1 and 42 days of applying chemicals. NH3, CO₂ emission in control treatment were recorded high from other treatments throughout the experiment but reduced with time due to reduction in moisture content. In other treatments NH3 were 0 ppm at first 2 weeks then the emission starts slowly between 3rd and 6<sup>th</sup> weeks. At end of 6<sup>th</sup> week lowest NH3 and CO₂ emission was recorded at T1. pH and EC showed the inverse relationship, in control treatment high pH and low EC values were found, and in other treatments low pH and high EC values were found. After 42 days Nitrogen were reduces significantly from control treatment, the high N content were found in T1. Water Soluble Phosphorus were much lower in treated poultry litters than untreated both after 1 day and 42 days. These data give us an indication that use of Alum and Ferric chloride as a blend can be more useful amendments for reducing NH3, CO₂, pH and Moisture content which help in poultry productivity, controlling pollution and poultry litter as a fertilizer.
Occurrence and diversity of entomopathogenic fungi in cultivated and uncultivated soils in Pakistan
Waqas Wakil,M. Usman GHAZANFAR,Tahira RIASAT,권용정,Mirza Abdul QAYYUM,Muhammad YASIN 한국곤충학회 2013 Entomological Research Vol.43 No.1
The distribution of entomopathogenic fungi in various geographical areas of Punjab, Pakistan, is poorly understood. The present study was planned to explore the occurrence and diversity of entomopathogenic fungi from soils collected from cultivated and non‐cultivated habitats. The detailed survey of different habitats (crop fields, fruits, vegetables, forests) was conducted to collect soil samples and the associated fungi were isolated using Galleria bait method. Among 210 soil samples, 168 fungal isolates were recovered and identified, with 98 from forests, 32 from vegetables, 30 from field crops and 8 from fruits. The major entomopathogenic fungi recovered from these samples were Beauveria bassiana, Metarhizium anisopliae, Paecilomyces lilacinus, B. brongniartii, P. chlamydosporia and Lecanicillium attenuatum. The diversity of entomopathogenic fungi was greater in soil samples from forests compared to crop fields, vegetables and fruits, respectively. The geographical attributes (altitude, longitude, latitude) greatly influenced the occurrence of entomopathogenic fungi with the highest number of isolates found from >600 m altitude, 33°–34′N latitude, and 73°74′E longitude from soil samples. The results of the surveys clearly indicated that the entomopathogenic fungi are distributed in the soils which may be used in successful IPM programs in future.