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Possibility of cellulose-based electro-active paper energy scavenging transducer.
Abas, Zafar,Kim, Heung Soo,Zhai, Lindong,Kim, Jaehwan,Kim, Joo Hyung American Scientific Publishers 2014 Journal of nanoscience and nanotechnology Vol.14 No.10
<P>In this paper, a cellulose-based Electro-Active Paper (EAPap) energy scavenging transducer is presented. Cellulose is proven as a smart material, and exhibits piezoelectric effect. Specimens were prepared by coating gold electrodes on both sides of cellulose film. The fabricated specimens were tested by a base excited aluminum cantilever beam at resonant frequency. Different tests were performed with single and multiple parallel connected electrodes coated on the cellulose film. A maximum of 131 mV output voltage was measured, when three electrodes were connected in parallel. It was observed that voltage output increases significantly with the area of electrodes. From these results, it can be concluded that the piezoelectricity of cellulose-based EAPap can be used in energy transduction application.</P>
Experimental Study of Vibrational Energy Harvesting Using Electro-Active Paper
Zafar Abas,김흥수,Lindong Zhai,김재환 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.6
This paper presents an estimation of power output produced by an Electro-Active Paper (EAPap) energy harvesting transducer under base vibration. EAPap is very thin cellulose piezoelectric film, which exhibits a direct piezoelectric effect, when subjected to stress. A 50×50 mm2 EAPap patch was bonded on a 100×50×1 mm3 aluminum cantilever structure. Energy harvesting tests were performed on the energy harvesting transducer, without and with a 2 grams proof mass near the tip of the cantilever beam. The voltage, current and power frequency response functions (FRFs) with respect to the base acceleration are identified and presented. The Voltage FRFs show a monotonic trend with increasing the load resistor from 100 kΩ to 1 MΩ, and the current FRFs also demonstrate monotonic dynamic behavior, but the trend is opposite to the voltage FRFs. In contrast to the voltage and current FRFs, the output power FRFs do not show a monotonic trend, exhibiting the maximum value of 150 μW/g2 at 75.1 Hz without the proof mass. The output power increases to 392 μW/g2 at 62.2 Hz when the proof mass is attached. This preliminary study indicates that EAPap is promising for energy harvesting transducers under vibration environment.
Ali Abas Wani,Dalbir Singh Sogi,Preeti Singh,Uma Shankar Shivhare 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.4
Watermelon (Citrullus lanatus) seed meal contains significant amount of extractable protein which can be used as nutritional and functional ingredients in food formulations. Alkali (0.1 M) and NaCl (0.5 M) were used to prepare protein isolates and concentrates from the defatted watermelon seed meals. Protein isolates reported protein yield of 35.15-38.27% and protein content (79.05-83.79%) which was significantly (p≤0.05) higher than the protein concentrates. SDS-PAGE of protein isolates and concentrates showed major polypeptides in the range of 74.72-110.42 kDa. Also, in vitro pepsin digestibility showed that most of the proteins were readily digested within 30 min of hydrolysis. Amino acids were dominated by arginine, aspartic, and glutamic acid. DSC results indicated that protein concentrates had significantly (p≤0.05) higher denaturation temperatures than protein isolates. The functional properties of concentrates in terms of solubility and surface properties were better than respective isolates. The results indicated that NaCl extracted proteins had comparatively better functional properties but their yield is significantly lower than respective protein isolates.
System Identification for an Autonomous Quadrotor using Extended and Unscented Kalman Filters
Norafizah Abas,Ari Legowo,Rini Akmeliawati 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
This paper presents aerodynamic parameters estimation techniques for an autonomous quadrotor through the implementation of Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF). EKF and UKF have known to be typical estimation techniques used to estimate the state vectors and parameters of nonlinear dynamical systems. In this paper, three main processes are highlighted; dynamic modeling of the quadrotor, the implementation of EKF and the implementation of UKF algorithms. The aim is to identify and estimate the needed parameters for an autonomous quadrotor. The obtained results demonstrate the performances of EKF and UKF based on the flight test applied to the quadrotor system.
Shkembi Abas,Le Aurora B.,Neitzel Richard L. 한국산업안전보건공단 산업안전보건연구원 2023 Safety and health at work Vol.14 No.1
Background: Effort–reward imbalance (ERI) and overcommitment at work have been associated poorer mental health. However, nonlinear and nonadditive effects have not been investigated previously. Methods: The association between effort, reward, and overcommitment with odds of poorer mental health was examined among a sample of 68 formal United States waste workers (87% male). Traditional, logistic regression and Bayesian Kernel machine regression (BKMR) modeling was conducted. Models controlled for age, education level, race, gender, union status, and physical health status. Results: The traditional, logistic regression found only overcommitment was significantly associated with poorer mental health (IQR increase: OR = 6.7; 95% CI: 1.7 to 25.5) when controlling for effort and reward (or ERI alone). Results from the BKMR showed that a simultaneous IQR increase in higher effort, lower reward, and higher overcommitment was associated with 6.6 (95% CI: 1.7 to 33.4) times significantly higher odds of poorer mental health. An IQR increase in overcommitment was associated with 5.6 (95% CI: 1.6 to 24.9) times significantly higher odds of poorer mental health when controlling for effort and reward. Higher effort and lower reward at work may not always be associated with poorer mental health but rather they may have an inverse, U-shaped relationship with mental health. No interaction between effort, reward, or overcommitment was observed. Conclusion: When taking into the consideration the relationship between effort, reward, and overcommitment, overcommitment may be most indicative of poorer mental health. Organizations should assess their workers' perceptions of overcommitment to target potential areas of improvement to enhance mental health outcomes.
Reducing the PAPR of OFDM Systems by Random Variable Transformation
Montadar Abas Taher,Mandeep Jit Singh,Mahamod Bin Ismail,Salina Abdul Samad,Mohammad Tariqul Islam 한국전자통신연구원 2013 ETRI Journal Vol.35 No.4
Peak power reduction techniques in orthogonal frequency division multiplexing (OFDM) has been an important subject for many researchers for over 20 years. In this letter, we propose a side-information-free technique that is based on the concept of random variable (RV) transformation. The suggested method transforms RVs into other RVs, aiming to reshape the constellation that will consequently produce OFDM symbols with a reduced peak-to-average power ratio. The proposed method has no limitation on the mapping type or the mapping order and has no significant effect on the bit error rate performance compared to other methods presented in the literature. Additionally, the computational complexity does not increase.