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A Joint Evaluation of Energy-Efficient Downlink Scheduling and Partial CQI Feedback for LTE Video Transmission
No full textA green cellular technology is proposed to optimize the energy and spectrum resources. Such optimization will require perfect channel state information at the transmitting base station. However, reporting the channel status of the entire bandwidth requires huge undesirable feedback overhead. Therefore, the aim of this paper is to optimize the energy and bandwidth resources while maintaining quality-of-service at the downlink when a partial feedback is considered. In this paper, a modified downlink scheduler based on a Packet Prediction Mechanism (PPM) is conducted at the eNodeB to optimize the energy and spectrum resources. On the user equipment side, a partial channel feedback scheme based on an adaptive feedback threshold is developed. A primary concern of this feedback scheme is to reduce the uplink signaling overhead without a substantial loss in downlink performances. Finally, the downlink packet scheduling and the partial feedback are jointly evaluated to further enhance the system performance. Based on a system-level simulation results, the proposed energy-efficient scheduling with partial feedback has achieved an improvement in EE of up to 79% compared to the PPM scheduler. Besides, it minimizes the degradation caused by the partial channel quality indicator feedback. Thus, the proposed two-sided algorithm gives the best tradeoff between uplink and downlink performances
A simple method for chromium speciation analysis in contaminated water using APDC and a pre-heated glass tube followed by HPLC-PDA
No full textIn this study, a simple sample preparation method was developed for the determination of tri-and hexavalent chromium in water samples. It utilizes a pre-heated customized glass tube (CGT), to supply the heat energy required for the reaction of Cr(III) with ammonium pyrrolidinedithiocarbamate (APDC). The products of the Cr complexes, tris(1-pyrrolidinecarbodithioato)chromium(III) and bis(1-pyrrolidinecarbodithioato)[1-pyrrolidinecarbodithio(thioperoxoato)]chromium(III) were chromatographed with Shimadzu LC-20AT and Zobax Eclipse C18 (150 mm × 4.6 mm, 5 µm) column using ACN: Water, (7:3, v/v) as the mobile phase. The concentration of Cr(III) ranged from 0.06 mgL−1 to 0.09 mgL−1 and that of Cr(VI) was between 0.02 mg L−1 to 0.04 mgL−1 in the samples. Percentage recoveries from spiked real samples were between 87% (tap water) to 110% (wastewater) for Cr(III) and 92% (pond water) to 117% (tap water) for Cr(VI). The limits of detection (LODs) were 0.0029 mg L−1 and 0.0014 mg/L−1 for Cr(III) Cr(VI) respectively. While the limits of quantitation (LOQs), were 0.0098 mg L−1 and 0.0047 mg L−1 for Cr(III) and Cr(VI) respectively. Method precision (RSD (%)) was 3.3% and 3.5% for Cr(III) and Cr(VI) respectively. The developed method was applied for the speciation analysis of chromium in drinking water, tap water, wastewater, river water, and pond water samples. Our findings proved the method is simple and inexpensive. The method was validated by the analysis of a certified reference material (CRM) SLRS-4. The percentage recovery and RSD(%) from the spiked CRM were 91% and 115% and 0.32% and 1.4% for Cr(III) and Cr(VI) respectively
Durability Indicators for Sustainable Self-Consolidating High-Strength Concrete Incorporating Palm Oil Fuel Ash
No full textThis paper presents the durability indicators for sustainable self-consolidating high-strength concrete (SCHSC) including palm oil fuel ash (POFA) as a supplementary cementing material (SCM). SCHSC mixes were prepared by varying the water to binder (W/B) ratio and POFA content. The W/B ratio was varied in the range of 0.25 to 0.40, and the POFA content differed in the range of 10-30% to produce the desired SCHSC mixes. The tests conducted on the freshly mixed SCHSCs to evaluate their filling ability, passing ability, and segregation resistance were slump flow, J-ring flow, and sieve segregation, respectively. To evaluate the durability of the hardened SCHSCs, the compressive strength, water absorption, and permeable porosity were examined along with the ultrasonic pulse velocity (UPV). The correlations between different hardened properties were derived to ascertain the durability indicators for sustainable SCHSCs. It was observed that most of the SCHSCs possessed excellent filling ability and passing ability with adequate segregation resistance. The test results also revealed that the compressive strength and UPV increased, whereas the water absorption and permeable porosity decreased with a lower W/B ratio and a higher amount of POFA (up to 20% weight content). Moreover, strong correlations were found between the different hardened properties of SCHSC. These correlations were used to determine the durability indicators for sustainable SCHSC with respect to compressive strength, permeable porosity, and water absorption. In accordance with the derived durability indicators, the sustainable SCHSC mixes produced in this study had the durability levels varying from "high" to "outstanding"
Design, development and testing of a novel power augmented cross-axis-wind-turbine
Get PDFThe horizontal-axis-wind-turbine (HAWT) is popular in the wind power industry nowadays due to its high power extraction capability. However, the HAWT has some complications due to high turbulent, low speed and changing direction of wind, which inhibits its full performance. Some vertical-axis-wind-turbine (VAWT) designs were able to function well under these wind conditions but they usually produce less power compared to HAWT. Thus, a new type of wind turbine design is proposed to overcome the weaknesses of HAWT and VAWT namely the cross-axis-wind-turbine (CAWT). The CAWT has three vertical and six horizontal blades, which interacts with horizontal and vertical wind. The vertical wind is generated by introducing a deflector or an omni-directional shroud to direct the oncoming horizontal wind towards the horizontal blades. The shroud consists of stacked ring-like deflecting planes supported by vertical webs and an inverted funnel-shaped base. It was designed to produce vertical wind components from any horizontal wind direction. The performance of the shroud was investigated by using a computational fluid dynamics (CFD) software, which showed significant vertical wind component located at the top of the proposed shroud. Experiments using deflectors to guide the oncoming airflow upward were designed to test the CAWT performance with various inclination angles (from 30 to 45°, with 5º increment). The experiments were also conducted with different pitch angles to identify the characteristics of the horizontal blades of the CAWT. A conventional H-rotor VAWT was tested under the same experimental conditions for benchmarking purposes. The results showed that the CAWT produced significant improvements in power output and rotational speed performance compared to the VAWT. It was found that the CAWT’s peak power coefficients (integrated with the 45° deflector) were increased significantly by 103 to 175 % at different tip speed ratios for various horizontal blade pitch angles. The study showed that the proposed CAWT was able to achieve maximum RPM of up to 112% higher than that of the VAWT counterpart as well as better starting behaviour. These preliminary findings show the potential of CAWT for future applications in many locations, creating significant opportunities for wind energy devices
A power system network splitting strategy based on contingency analysis
No full textThis paper proposes a network splitting strategy following critical line outages based on N-1 contingency analysis. Network splitting is the best option for certain critical outages when the tendency of severe cascading failures is very high. Network splitting is executed by splitting the power system network into feasible set of islands. Thus, it is essential to identify the optimal splitting solution (in terms of minimal power flow disruption) that satisfies certain constraints. This paper determines the optimal splitting solution for each of the critical line outage using discrete evolutionary programming (DEP) optimization technique assisted by heuristic initialization approach. Heuristic initialization provides the best initial cutsets which will guide the optimization technique to find the optimal splitting solution. Generation-load balance and transmission line overloading analysis are carried out in each island to ensure the steady state stability is achieved. Load shedding scheme is initiated if the power balance criterion is violated in any island to sustain the generation-load balance. The proposed technique is validated on the IEEE 118 bus system. Results show that the proposed approach produces an optimal splitting solution with lower power flow disruption during network splitting execution
An empirical investigation of campus portal usage
No full textThis study has determined the determinants of the perceived ease of use and perceived usefulness and their influence on campus portal usage. A quantitative approach was employed, using a five-point Likert scale questionnaire, adapted from previous studies. Data were gathered through a survey conducted with 341 staff working in the University of Malaya and were analysed using the partial least squares technique. The results indicate that the ease of finding and ease of understanding have a positive impact on the perceived ease of use of the campus portal. Furthermore, this study also reported a significant positive effect of service quality, information, and process on perceived usefulness of the campus portal. Our study suggests that the perceived ease of use and usefulness are vital towards enhancing the usage frequency and volume of the campus portal. This study broadens the knowledge concerning factors that increase campus portal usage which will enable academic institutions to refine the campus portal thus enhancing the portal usage
Antimelanogenesis and Anti-Inflammatory Activity of Selected Culinary-Medicinal Mushrooms
No full textFive culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bispo-rus (white and brown), Ganoderma lucidum, Hypsizygus marmoreus, Pleurotusfloridanus, and P. pulmonarius. These species were selected for use in the current study, the aim of which was to investigate the antimelanogenesis and anti-inflammatory activity ofthese mushrooms in an attempt to evaluate their potential use in cosmeceuticals. Mushroom fruiting bodies were extracted with hot water, and the extracts were freeze-dried before testing. The antimelanogenesis activity of the extracts was determined by cell viability assay, measurement of intracellular melanin content, and cellular tyrosinase assay with B16F10 melanoma cells. The anti-inflammatory activity of the mushroom extracts was tested by measuring the levels of nitric oxide (NO), tumor necrosis factor (TNF)-a, and interleukin-10 excreted by RAW264.7 macrophages. Brown A. bisporus reduced intracellular melanin content to the largest extent-up to 57.05 ± 3.90%-without a cytotoxic effect on B16F10 melanoma cells. This extract also reduced cellular tyrosinase activity to 17.93 ± 2.65%, performing better than kojic acid, the positive control. In parallel, the extract from brown A. bisporus, at the highest concentration tested, has appreciable anti-inflammatory activity through reductions ofNO and TNF-a levels. The other 5 extracts showed moderate antimelanogenesis and anti-inflammatory activities. In summary, our findings show that A. bisporus (brown) extract has the potential to be used as an ingredient in whitening skincare products and to sooth the inflammatory response on the skin
A mode-locked thulium-doped fiber laser with multiple wavelength output based on a nonlinear loop mirror
No full textA nonlinear polarization rotation based all-fiber passively mode-locked Thulium-doped fiber laser (TDFL) is demonstrated by using a fiber loop mirror. Polarization dependent isolator and polarization controller are inserted between ports 3 and 1 of the circulator to form a fiber loop mirror and provides intensity dependent loss for the mode-locking pulse generation. The TDFL produces a multiple wavelength output centered at 1857 nm using a 5 m long thulium-doped fiber (TDF) as a gain medium as well as nonlinear medium. The mode-locked emission is obtained at threshold pump power of 857 mW with consistent pulse repetition rate of 68 MHz. Maximum pulse energy is calculated as 0.94 nJ at pump power of 1224 mW, whereas the minimum pulse width is estimated to be approximately 65 ps corresponding to sech2 pulse profile
The evaluation of a possible future Sino-Japanese armed conflict through the application of the ACEI-model
No full textThere is relatively little formal modeling of the economic effects of armed conflicts even though they have substantial economic effects. We set forth a new model, namely the armed conflict economic impact model–ACEI-Model. The model looks at the economic effects of war in three different stages: (i) pre-conflict stage; (ii) armed conflict stage; and (iii) post-conflict stage. The model is based on economic desgrowth (-δ) and other new conceptual indicators. We evaluate an imaginary armed conflict between China and Japan by applying the ACEI-Model
Symposium Celebrating Women Surgeons Around the World
No full textIntroduction
We must thank Dr. Sanziana Roman for organizing this symposium about women in surgery. Powerful testimonials from women surgeons, from Europe to the United States, from Africa to Australia and Asia. Each of them is different, as it reflects the culture of the place where their career took place. However, they all have in common the struggle to establish themselves in the surgical profession, traditionally a male-dominated field.
Over the last two decades, the situation has clearly improved. Today in most medical schools about 50% of the students are women, and a similar percentage is present in many surgical residency programs. Twenty-one Departments of Surgery in the United States are led by women, a major change as compared to only 5 years ago. Much more must be done to establish a work environment where women are as welcomed and respected as men; where they are accepted as surgeons, and not as women surgeons, treasuring the contribution they can give.
We do hope that..