A hybrid GA–PS–SQP method to solve power system valve-point economic dispatch problems

This study presents a new approach based on a hybrid algorithm consisting of Genetic Algorithm (GA), Pattern Search (PS) and Sequential Quadratic Programming (SQP) techniques to solve the well-known power system Economic dispatch problem (ED). GA is the main optimizer of the algorithm, whereas PS and SQP are used to fine tune the results of GA to increase confidence in the solution. For illustrative purposes, the algorithm has been applied to various test systems to assess its effectiveness. Furthermore, convergence characteristics and robustness of the proposed method have been explored through comparison with results reported in literature. The outcome is very encouraging and suggests that the hybrid GA–PS–SQP algorithm is very efficient in solving power system economic dispatch problem

LEADERSHIP STYLE AMONG MIDDLE MANAGERS IN SAUDI MINISTRY OF HEALTH

Background: Middle managers within ministry of health act under continuous pressure from board level to be successful leaders of today's and tomorrow's healthcare service. Leadership styles are important factors among middle managers to retain employees in organizations and to ensure a high quality of practice.Aims: Two main aims: to examine the leadership style(s) of middle managers as perceived by them as leader from different departments of the Saudi Ministry of Health, and to examine the leadership style(s) of the middle managers as perceived by their subordinates as raters from different departments of the Saudi Ministry of Health.Materials and methods: A cross-sectional descriptive design was used to answer the research questions. A convenience sample of 121 participants, 30 middle managers and 91 subordinates, who were recruited through different departments at Saudi Ministry of Health during the period of June 2010 through September 2010.Participants were subjected to Univariate and Multivariate analysis. The Multifactor Leadership Questionnaire (MLQ) was used to collect data.Results: the mean ratings of all four components of transformational leadership for the subordinates and middle managers were between 2.90 to 3.29 .The mean ratings for contingent reward and management by exception active were 3.30 and 2.50 respectively and this was well within the optimum range as suggested by Bass. Management by exception passive and laissez-faire showed mean ratings of 1.67 and 1.25 respectively. The correlation coefficients among transformational leadership style and each variable of, satisfaction, effectiveness and extra effort for raters and leaders sample was high positively reached (r = .72, p< 0.05) , (r = .81, p< 0.05) , (r = .80, p< 0.05) respectively, The correlation coefficients among transactional leadership style and each variable of, satisfaction, effectiveness and extra effort for raters and leaders sample was high positively reached (r = .20, p<0.05) , (r = .44, p< 0.05) , (r = .35, p< 0.05) respectively, and The correlation coefficients among laissez -Faire leadership style and each variable of, satisfaction, effectiveness and extra effort for raters and leaders sample was high negatively reached (r = -.48, p< 0.05) , (r = -.46, p< 0.05) , (r = -.43, p< 0.05) respectively. There are agreement between leaders and raters on transformational, transactional and laissez-faire as distributive in Saudi Ministry of Health in kingdom of Saudi Arabia. The result showed there was no significant difference on the MLQ factors for raters and Leader due to gender, marital status, and age. Also , the analysis showed significant differences among raters’ opinions due to work experiences as contingent reward and extra effort in favor of raters who experience of them more than ˃ 6 Month, and finally, the analysis showed there significant differences among raters’ opinions due to period working with leaders as transformational, idealized Influence attributed, inspirational motivation, intellectual stimulation, contingent reward, and effectiveness in favor of raters who working with leaders for a period between 6 months - ˂ 1 year, but significant differences among raters’ opinions due to period working with leaders as Laissez –Faire in favor of raters who working with leaders for a period between 1 year - 2 years.Conclusions: transformational leadership can contribute a lot to the effectiveness of organizations and that there is a need for further investigation of leadership at different levels

Development of Analytical Method for Detection of Some Pharmaceuticals in Surface Water

Purpose: To develop and validate a simple method using solid – phase extraction along with liquid chromatography–time of flight mass spectrometry for the analysis of pharmaceuticals in surface water of Tangkas River, Malaysia.Methods: Liquid chromatography (LC) was performed on a Dionex Ultimate 3000/LC 09115047 (USA) system equipped with a vacuum degasser, a quaternary pump, an autosampler and UV-Vis diod array detector. Chromatography was performed on a Thermo Scientific C18 (250 mm x 2.1 mm, i.d.: 5μm) column. The injection volume was 20 μL. All  compounds (hydrochlorothiazide, gliclazide, diclofenac-Na and mefenamic acid) were analysed in negative ion (NI) mode and eluted off the column with a mobile phase consisting of (A) 0.1% formic acid (FA) in deionised water (DIW) and (B) 40% acetonitrile (ACN) in methanol (MeOH) at 0.3 ml/min. Mass spectrometry was performed on a time of flight (TOF) instrument.Results: The linearity range, 5 - 500 ng/mL, provided a determination coefficient (R2) > 0.99 for all compounds. The limit of detection (LOD) ranged from 65 - 136 ng/L while recovery ranged from 45 - 111.2 % in the river water. Two pharmaceutical compounds were detected in the surface water samples: diclofenac sodium and mefenamic acid at concentrations of 340 and 545 ng/L, respectively.Conclusion: The developed method is linear in the range 5 - 500 ng/mL, and precise and acceptable recoveries were obtained. In addition, this method is suitable to identify and quantify trace concentrations of diclofenac sodium and mefenamic acid in surface water.Keywords: Diclofenac, Mefenamic acid, Electrospray Ionization, Mass spectrometry, Solid phase extraction (SPE), Tangkas river, Collision energy

A systematic review on bio-sequestration of carbon dioxide in bio-concrete systems: a future direction

The paper reviewed the current perspectives on the development of carbon diox�ide (CO2) sequestration through its process conversion into calcite. The process occurs in either geological or biological systems. However, geological sequestration is an expensive process, which is slow in comparison to bio-sequestration. Recently, the bio-sequestration of atmospheric CO2 into the soil using microorgan�isms such as algae has been investigated. However, the algae cannot be used in the bio-concrete due to their nature as phototrophic organisms. In contrast, bac�teria are the most potent organisms in bio-concrete technology. The use of bacter�ial species in the bio-aerated concrete bricks (B-ACB) and its potential to bio�sequestrate CO2 represents a future strategy to reduce high CO2 pollution. Bacterial cells can capture CO2 by accelerating the carbonation processes, which convert CO2 into calcium carbonate (CaCO3) via carbon anhydrase and urease enzymes. The present paper aimed to highlight and discuss the applicability of bacteria in the B-ACB for capturing and storing CO2. It is evident from the literature that the new trends to use bio-concrete might contribute to the reduction of CO2 by accelerating the carbonation process and strengthening the B-ACB

Tea and coffee consumption in relation to vitamin D and calcium levels in Saudi adolescents

Background Coffee and tea consumption was hypothesized to interact with variants of vitamin D-receptor polymorphisms, but limited evidence exists. Here we determine for the first time whether increased coffee and tea consumption affects circulating levels of 25-hydroxyvitamin D in a cohort of Saudi adolescents. Methods A total of 330 randomly selected Saudi adolescents were included. Anthropometrics were recorded and fasting blood samples were analyzed for routine analysis of fasting glucose, lipid levels, calcium, albumin and phosphorous. Frequency of coffee and tea intake was noted. 25-hydroxyvitamin D levels were measured using enzyme-linked immunosorbent assays. Results Improved lipid profiles were observed in both boys and girls, as demonstrated by increased levels of HDL-cholesterol, even after controlling for age and BMI, among those consuming 9–12 cups of coffee/week. Vitamin D levels were significantly highest among those consuming 9–12 cups of tea/week in all subjects (p-value 0.009) independent of age, gender, BMI, physical activity and sun exposure. Conclusion This study suggests a link between tea consumption and vitamin D levels in a cohort of Saudi adolescents, independent of age, BMI, gender, physical activity and sun exposure. These findings should be confirmed prospectively

Fracture properties investigation of Artocarpus Odoratissimus composite with Polypropylene (PP)

Wood plastic composites (WPC) were done using a matrix of polypropylene (PP) thermoplastic resin with wood fibre from Artocarpus odoratissimus as filler. The purpose of this study is to investigate the fracture properties of Artocarpus odoratissimus composite with PP. The WPC was manufactured by a hot - press technique with varying formulations which are 10:0 (100% pure PP), 50:50 (40 g of wood fiber and 40 g of PP) and 60:40 (48 g of wood fiber and 32 g of PP). The mechanical properties were investigated. Tensile and flexural were carried out according to ASTM D 638 and ASTM D 790. The results were analysed to calculate the tensile strength. Tensile strength at break is ranged from 13.2 N/mm2 to 21.7 N/mm2 . While, the flexural strength obtained is varying from 14.7 N/mm2 to 31.1 N/mm2 . The results of the experiment showed that tensile and flexural properties of the composite increased with the adding of wood fiber material. Finally, the Scanning Electron Microscope (SEM), have been done to study the fracture behaviour of the WPC specimens

An adaptive delayed acknowledgment strategy to improve TCP performance in multi-hop wireless networks.

In multi-hop wireless networks, transmission control protocol (TCP) suffers from performance deterioration due to poor wireless channel characteristics. Earlier studies have shown that the small TCP acknowledgments consume as much wireless resources as the long TCP data packets. Moreover, generating an acknowledgment (ACK) for each incoming data packet reduces the performance of TCP. The main factor affecting TCP performance in multi-hop wireless networks is the contention and collision between ACK and data packets that share the same path. Thus, lowering the number of ACKs using the delayed acknowledgment option defined in IETF RFC 1122 will improve TCP performance. However, large cumulative ACKs will induce packet loss due to retransmission time-out at the sender side of TCP. Motivated by this understanding, we propose a new TCP receiver with an adaptive delayed ACK strategy to improve TCP performance in multi-hop wireless networks. Extensive simulations have been done to prove and evaluate our strategy over different topologies. The simulation results demonstrate that our strategy can improve TCP performance significantly

Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of 76Ge to Excited States of 76Se

The MAJORANA DEMONSTRATOR is searching for double-beta decay of 76Ge to excited states (E.S.) in 76Se using a modular array of high purity Germanium detectors. 76Ge can decay into three E.S.s of 76Se. The E.S. decays have a clear event signature consisting of a ββ-decay with the prompt emission of one or two γ-rays, resulting in with high probability in a multi-site event. The granularity of the DEMONSTRATOR detector array enables powerful discrimination of this event signature from backgrounds. Using 21.3 kg-y of isotopic exposure, the DEMONSTRATOR has set world leading limits for each E.S. decay, with 90% CL lower half-life limits in the range of (0.56 2.1) ⋅ 1024 y. In particular, for the 2v transition to the first 0+ E.S. of 76Se, a lower half-life limit of 0.68 ⋅ 1024 at 90% CL was achieved

Observations on the Electrostatic Discharge Threats to Aircraft Body and to Aerospace Electronics

Electrostatic Discharge (ESD) is a well-known threat to aerospace vehicles and microelectronic systems. This is especially so with the increased use of non-metallic, composite material for the aircraft body. Moreover, the severe lightning flashes to aircraft also commence with ESD on the aircraft body. The ESD results in the initiation of positive leaders that grow towards the thundercloud from one part of the aircraft. Moreover, a negative leader is launched towards the ground or another cloud. In this paper, we discuss the induced electric charges due to the vertical electric field component of the thundercloud charge center. Further, the electric currents induced on the surface of the aircraft body or equipment by the horizontal component of the thundercloud generated electric field is examined. From the electrostatic fields computed prior to the initiation of corona or the initial leader, we show that in addition to the most commonly identified part of the aircraft from which leaders are initiated, namely the radome, the main wing tips, the curved surface of the mid-wing and the stabilizer tips experience highly enhanced electric fields. These electric field enhancements may also lead to the generation of electric breakdown

Lightning Protection of Aircraft, Power Systems and Houses Containing IT Network Electronics

Over the past decade, there has been an increasing interest in lightning and lightning protection for several reasons, including the proliferation of microelectronic equipment and IT systems in mission-critical systems as well as in everyday use in banks to homes. Lightning strikes to power lines produce large fast transient voltage and current surges which trickle down to IT systems, military command and control systems as well as to several other microelectronic equipment and control systems. Moreover, aircraft are struck by lightning when it is parked on ground, landing and taking off or in military operations where the aircraft has to keep close to the ground even when the atmosphere is electrified by thunderclouds. In this paper, we explore the protection of electronic equipment, structures and in-house systems from lightning. The paper will also explore lightning related Electrostatic Discharge (ESD) threat to aerospace vehicles and microelectronic systems. This is especially so with the increased use of non-metallic, composite material for the aircraft body. Moreover, the paper will report on the important lightning techniques used in the protection of electric power systems and houses