1,275 research outputs found

    Design and implementation of a laboratory scale single axis solar tracking system

    Get PDF
    The renewable solar energy can be produced by using the Photovoltaic (PV) panel which converts the solar energy to the electrical energy. Global warming can be reduced by using the solar energy to generate electricity. Therefore in this project, an active type single axis solar tracking system is designed and constructed. The solar tracking system can enhance the amount of solar energy harvest throughout the day as compared to the fixed solar panel. A laboratory-scale single axis solar tracking system is developed to have a better understanding on the working mechanism of the solar tracking system. By using the laboratory-scale system, the system becomes portable and convenient to be allocated at the suitable workplace for solar tracking process. Moreover, the laboratory scale solar tracking system can be easily controlled and programmed by the users such as angle of rotation of the solar panel and the direction of rotation. In this project, microcontroller is used as an integrated control unit and the plant is actuated by the DC geared motor. The validity of the laboratory-scale single axis solar tracking system was examined experimentally. The solar tracking system operates by rotating to the desired angle in every hour. The workspace of the solar tracking system is determined and identified. The solar tracking system workspace must be identified and examined carefully before the installation to prevent any accidents occurred during operation. This research is important for Faculty of Electrical Engineering of Universiti Teknikal Malaysia Melaka (UTeM) to identify the safety workspace for the solar tracking system due to the actual solar tracking system plant is still cannot be operated because of the limited workspace

    Development of a standardized in-hospital cardiopulmonary resuscitation set-up

    Get PDF
    Objective. This study evaluated whether chest compression in a standardized inhospital cardiopulmonary resuscitation (CPR) set-up can be performed as effectively as when the rescuer is kneeling beside the patient lying on the floor. Specifically, the in-hospital test was standardized according to the rescuers’ average knee height. Methods. Experimental intervention (test 1) was a standardized, in-hospital CPR set-up: first, the bed height was fixed at 70 cm. Second, the height difference between the bed and a step stool was set to the average knee height of the CPR team members (45 cm). Control intervention (test 2) was kneeling on floor. Thirty-eight medical doctors on the CPR team each performed 2 minutes of chest compressions in test 1 and 2 in random order (cross-over trial). A Little Anne was used as a simulated patient who had experienced cardiac arrest. Chest compression parameters, such as average depth and rate, were measured using an accelerometer device. Results. In all tests, the average depths were those recommended in the most recent CPR guidelines (50–60 mm); there were no significant differences between Tests 1 and 2 (53.1 ± 4.3 mm vs. 52.6 ± 4.8 mm, respectively; p = 0.398). The average rate in Test 2 (119.1 ± 12.4 numbers/min) was slightly faster than that in Test 1 (116.4 ± 10.2 numbers/ min; p = 0.028). No differences were observed in any other parameters. Conclusions. Chest compression quality in our standardized in-hospital CPR set-up was similar with that performed in a kneeling position on the floor. Trial Registration: Clinical Research Information Service: KCT000159

    Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials

    Get PDF
    Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (similar to 97.5 cd/A, similar to 35.5% photons per electron), green (similar to 101.5 cd/A, similar to 29.0% photons per electron), and white (similar to 74.2 cd/A, similar to 28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices.

    Transcriptional activation of hypoxia-inducible factor-1 (HIF-1) in myeloid cells promotes angiogenesis through VEGF and S100A8

    Get PDF
    Emerging evidence indicates that myeloid cells are essential for promoting new blood vessel formation by secreting various angiogenic factors. Given that hypoxia-inducible factor (HIF) is a critical regulator for angiogenesis, we questioned whether HIF in myeloid cells also plays a role in promoting angiogenesis. To address this question, we generated a unique strain of myeloid-specific knockout mice targeting HIF pathways using human S100A8 as a myeloid-specific promoter. We observed that mutant mice where HIF-1 is transcriptionally activated in myeloid cells (by deletion of the von Hippel-Lindau gene) resulted in erythema, enhanced neovascularization in matrigel plugs, and increased production of vascular endothelial growth factor (VEGF) in the bone marrow, all of which were completely abrogated by either genetic or pharmacological inactivation of HIF-1. We further found that monocytes were the major effector producing VEGF and S100A8 proteins driving neovascularization in matrigel. Moreover, by using a mouse model of hindlimb ischemia we observed significantly improved blood flow in mice intramuscularly injected with HIF-1-activated monocytes. This study therefore demonstrates that HIF-1 activation in myeloid cells promotes angiogenesis through VEGF and S100A8 and that this may become an attractive therapeutic strategy to treat diseases with vascular defects.X1137Ysciescopu
    corecore