Hybrid iterative learning control of a flexible manipulator

This paper presents an investigation into the development of a hybrid control scheme with iterative learning for input tracking and end-point vibration suppression of a flexible manipulator system. The dynamic model of the system is derived using the finite element method. Initially, a collocated proportional-derivative (PD) controller using hub angle and hub velocity feedback is developed for control of rigid-body motion of the system. This is then extended to incorporate a non-collocated proportional-integral-derivative (PID) controller with iterative learning for control of vibration of the system. Simulation results of the response of the manipulator with the controllers are presented in the time and frequency domains. The performance of the hybrid iterative learning control scheme is assessed in terms of input tracking and level of vibration reduction in comparison to a conventionally designed PD-PID control scheme. The effectiveness of the control scheme in handling various payloads is also studied

Haplotype analyses of Orang Asli population in Taman Negara Pahang using Y-STR markers

There are many maternal line studies conducted for Orang Asli using mitochondrial DNA. This study focuses on the paternal line, specifically Y-STR and three markers were considered, namely DYS19, DYS390 and DYS391. These markers were used to compare 21 subjects comprising of 7 from Senoi tribes and 14 from Negrito tribes. The samples were collected from Kampung Kuala Atok, Kg. Sungai Tiang, Kg. Dedari, Kg. Krom, Kg. Teresek and Kg. Gam located in Taman Negara Pahang and villages nearby. From these, 14 haplotypes were gained with one of it shared by both tribes while the rest were unique to the tribe. The analyses conducted from the haplotype were gene diversity (GD), locus diversity (DL), haplotype diversity (HD) and discrimination capacity (DC). From the analysis, the GD values range from 0.2480 to 0.7108 whilst the DL values range from 0.2500 to 0.7446. The haplotype diversity and discrimination capacity values were 0.8875 and 0.6364, respectively. Since this work only studied the comparison between Senoi and Negrito, further analysis is going to include the other sub tribes of Orang Asli

Adaptation of a Mice Doppler Echocardiography Platform to Measure Cardiac Flow Velocities for Embryonic Chicken and Adult Zebrafish.

Ultrasonography is the most widely used imaging technique in cardiovascular medicine. In this technique, a piezoelectric crystal produces, sends, and receives high frequency ultrasound waves to the body to create an image of internal organs. It enables practical real time visualization in a non-invasive manner, making the modality especially useful to image dynamic cardiac structures. In the last few decades, echocardiography has been applied to cardiac disease models, mainly to rodents. While clinical echocardiography platforms can be used for relatively large animals such as pigs and rats, specialized systems are needed for smaller species. Theoretically, as the size of the imaged sample decreases, the frequency of the ultrasound transducer needed to image the sample increases. There are multiple modes of echocardiography imaging. In Doppler mode, erythrocytes blood flow velocities are measured from the frequency shift of the sent ultrasound waves compared to received echoes. Recorded data are then used to calculate cardiac function parameters such as cardiac output, as well as the hemodynamic shear stress levels in the heart and blood vessels. The multi-mode (i.e., b-mode, m-mode, Pulsed Doppler, Tissue Doppler, etc.) small animal ultrasound systems in the market can be used for most cardiac disease models including mice, embryonic chick and zebrafish. These systems are also associated with significant costs. Alternatively, there are more economical single-mode echocardiography platforms. However, these are originally built for mice studies and they need to be tested and evaluated for smaller experimental models. We recently adapted a mice Doppler echocardiography system to measure cardiac flow velocities for adult zebrafish and embryonic chicken. We successfully assessed cardiac function and hemodynamic shear stress for normal as well as for diseased embryonic chicken and zebrafish. In this paper, we will present our detailed protocols for Doppler flow measurements and further cardiac function analysis on these models using the setup. The protocols will involve detailed steps for animal stabilization, probe orientation for specific measurements, data acquisition, and data analysis. We believe this information will help cardiac researchers to establish similar echocardiography platforms in their labs in a practical and economical manner.Qatar National Research Fund (QNRF), National Priority Research Program NPRP 10-0123-170222. The publication of this article was funded by the Qatar National Library

Development of hand-arm model rig for tremor excitation

This paper describes the development of a handarm model rig to simulate human tremor behaviour. The experimental rig is designed as an apparatus to induce vibration along a hand-arm model. An Intra Vernacular (IV) Training arm is used as the handarm model. Displacement and acceleration behaviour at three selected points along the handarm model were recorded by mean of piezoelectric accelerometer. The data from the experiment can be used for further analysis of the human hand-arm tremor especially for Parkinson's disease (PD) patients. Results from the experiments are raw data which can later be used in designing an appropriate instrument that can suppress the hand tremor

Biosynthesis and in vivo wound healing abilities of Dactyloctenium aegyptium-mediated silver nanoparticles used as hydrogel dressing

Wounds offer a medium for the growth of pathogens and their entry into the body, which necessitates effective wound healing treatments. Herein, we report the green synthesis of silver nanoparticles (AgNPs) using Dactyloctenium aegyptium extract as a capping and reducing agent for wound healing applications. The synthesized nanoparticles were characterized by UV-Vis, FT-IR, SEM, XRD, and in vitro antibacterial activity. Nanoparticles were then incorporated into PVA, Na-alginate, and gelatin-based hydrogel dressings to investigate their in vivo wound healing capability in rats. The color change of the reaction mixture and the surface plasmon resonance (400 nm) confirmed the formation of AgNPs. FT-IR analysis revealed the involvement of plant extract phytochemicals in the capping and stabilization of nanoparticles. The nanoparticles were crystalline in nature, with an average crystallite size of 28.03 nm and exhibited antibacterial activity against S. aureus, P. aeruginosa, K. pneumoniae and E. coli (ZOI 19 ± 0.0, 9 ± 0.0, 13 ± 0.0, and 13 ± 0.0 mm respectively). Furthermore, silver nanoparticle-loaded hydrogels showed accelerated wound healing in rats compared to untreated rats and rats treated with a commercial product. Thus, the developed hydrogel dressing has the potential for clinical application in wound healing and infection treatment

Determination performance of thermoacoustic heat engine simulation by delta EC software

Thermoacoustic Heat Engine probably the most efficient energy source for electronic devices for the next 10 year ahead that require small amount of electrical energy to operate. This study was to simulate the Thermoacoustic Heat Engine (TAHE) standing wave system by conducting a Fluid Structure Interaction (FSI) by using a Thermoacoustic system's software named DeltaEC for better uderstanding on the fundamental of TAHE standing wave system. Some characteristics or parameters in the system that were studied in order to derive the fundamental knowledge of TAHE standing wave system. The thickness of Hot Heat Exchangers (Hot HX) plays the major role in affecting the maximum acoustic power generated, the level of onset temperature difference and maximum pressure amplitude followed by the stack length. Hot HX dimension (thickness) contributes nearly 3.3% changes in maximum acoustic power where the lowest thickness scores the highest maximum acoustic power generated. 2.9% of increment on maximum acoustic power generated by altering the length of the stack by 5 mm

Performance analysis of ultrathin junctionless double gate vertical MOSFETs

The main challenge in MOSFET minituarization is to form an ultra-shallow source/drain (S/D) junction with high doping concentration gradient, which requires an intricate S/D and channel engineering. Junctionless MOSFET configuration is an alternative solution for this issue as the junction and doping gradients is totally eliminated. A process simulation has been developed to investigate the impact of junctionless configuration on the double-gate vertical MOSFET. The result proves that the performance of junctionless double-gate vertical MOSFETs (JLDGVM) are superior to the conventional junctioned double-gate vertical MOSFETs (JDGVM). The results reveal that the drain current (ID) of the n-JLVDGM and p-JLVDGM could be tremendously enhanced by 57% and 60% respectively as the junctionless configuration was applied to the double-gate vertical MOSFET. In addition, junctionless devices also exhibit larger ION/IOFF ratio and smaller subthreshold slope compared to the junction devices, implying that the junctionless devices have better power consumption and faster switching capability