Performance Modelling of Steam Turbine Performance using Fuzzy Logic Membership Functions

A Fuzzy Inference System for predicting the performance of steam turbinebased on Rankine cycle is developed using a 144-rule based in analyzing the generated data for different inlet and outlet conditions. The result of efficiency for different types of membership functions and defuzzification method was obtained. Centroid method of defuzzification gave good results irrespective of the type of membership function with error less than 5%. However, other defuzzification methods gave good result for some types of membership functions. Result of different input data tested do not vary significantly (P<<0.05). It can therefore be concluded that Fuzzy logic can be used to effectively predict performance of a steam turbine. ©JASE

Theoretical foundations of the sound analog membrane potential that underlies coincidence detection in the barn owl

A wide variety of neurons encode temporal information via phase-locked spikes. In the avian auditory brainstem, neurons in the cochlear nucleus magnocellularis (NM) send phase-locked synaptic inputs to coincidence detector neurons in the nucleus laminaris (NL) that mediate sound localization. Previous modeling studies suggested that converging phase-locked synaptic inputs may give rise to a periodic oscillation in the membrane potential of their target neuron. Recent physiological recordings in vivo revealed that owl NL neurons changed their spike rates almost linearly with the amplitude of this oscillatory potential. The oscillatory potential was termed the sound analog potential, because of its resemblance to the waveform of the stimulus tone. The amplitude of the sound analog potential recorded in NL varied systematically with the interaural time difference (ITD), which is one of the most important cues for sound localization. In order to investigate the mechanisms underlying ITD computation in the NM-NL circuit, we provide detailed theoretical descriptions of how phase-locked inputs form oscillating membrane potentials. We derive analytical expressions that relate presynaptic, synaptic, and postsynaptic factors to the signal and noise components of the oscillation in both the synaptic conductance and the membrane potential. Numerical simulations demonstrate the validity of the theoretical formulations for the entire frequency ranges tested (1–8 kHz) and potential effects of higher harmonics on NL neurons with low best frequencies (<2 kHz)

Constraints on Hidden Photon Models from Electron g-2 and Hydrogen Spectroscopy

The hidden photon model is one of the simplest models which can explain the anomaly of the muon anomalous magnetic moment (g-2). The experimental constraints are studied in detail, which come from the electron g-2 and the hydrogen transition frequencies. The input parameters are set carefully in order to take dark photon contributions into account and to prevent the analysis from being self-inconsistent. It is shown that the new analysis provides a constraint severer by more than one order of magnitude than the previous result.Comment: 18 pages, 2 figures, 1 table. v2: minor correction

Nutrition and health status of HIV-infected adults on ARVs at AMREF clinic Kibera Urban Slum, Kenya

The health of people living with HIV and AIDS (PLWHA) is nutritionally challenged in many nations of the world. The scourge has reduced socio-economic progress globally and more so in sub-Saharan Africa (SSA) where its impact has been compounded by poverty and food insecurity. Good nutrition with proper drug use improves the quality of life for those infected but it is not known how PLWHA exposed to chronic malnutrition and food shortages from developing nations adjust their nutrition with use of Anti-Retro-viral Drugs (ARVs). This study assessed nutritional status, dietary practices, and dietary management of common illnesses that hinder daily food intake by the patients and use of ARVs with food recommendations provided by the health care givers. A descriptive case study design was used to sample 120 HIV-infected patients using systematic sampling procedure. These patients sought health care from an urban slum, Kibera AMREF clinic. Data were collected by anthropometric measurements, bio-chemical analysis, semi-structured questionnaire and secondary data. The Statistical Package for Social Sciences (SPSS) and the Nutri-Survey software packages were used to analyze data. Dietary intakes of micro-nutrients were inadequate for &gt;70% of the patients when compared to the Recommended Daily Requirements. When Body Mass Indices (BMI) were used, only 6.7% of the respondents were underweight (BMI&lt;18.5kg/m2) and 9.2% were overweight (BMI&gt; 25kg/m2), serum albumin test results (mean 3.34+0.06g/dl) showed 60.8% of the respondents were protein deficient and this was confirmed by low dietary protein intakes. The BMI was not related to dietary nutrient intakes, serum albumin and CD4 cell counts (p&gt;0.05). It appeared that there was no significant difference in BMI readings at different categories of CD4 cell count (p&gt;0.05) suggesting that the level of immunity did not affect weight gain with ARV as observed in many studies from developed countries. Malnutrition was, therefore, evident among the 60.8% of the cases as identified by serum albumin tests and food intake was not adequate (68%) for the patients as they ate once a day due to lack of food. National food and nutrition policy should incorporate food security boosting guidelines for the poor people infected with HIV and using ARVs.Keywords: Diet, Nutrition, HIV/AIDs, Serum albumin, CD4 cell count

SGR 0418+5729: a low-magnetic-field magnetar

Soft gamma-ray repeaters and anomalous X-ray pulsars are a small (but growing) group of X-ray sources characterized by the emission of short bursts and by a large variability in their persistent flux. They are believed to be magnetars, i.e. neutron stars powered by extreme magnetic fields 1E14-1E15 G). We found evidence for a magnetar with a low magnetic field, SGR 0418+5729, recently detected after it emitted bursts similar to those of soft gamma-ray repeaters. New X-ray observations show that its dipolar magnetic field cannot be greater than 8E12 G, well in the range of ordinary radio pulsars, implying that a high surface dipolar magnetic field is not necessarily required for magnetar-like activity. The magnetar population may thus include objects with a wider range of magnetic-field strengths, ages and evolutionary stages than observed so far.Comment: 4 pages, 2 figures; to appear in the Proceedings of the Pulsar Conference 2010, Chia, Sardinia (Italy), 10-15 October 201

New selection rules for resonant Raman scattering on quantum wires

The bosonisation technique is used to calculate the resonant Raman spectrum of a quantum wire with two electronic sub-bands occupied. Close to resonance, the cross section at frequencies in the region of the inter sub-band transitions shows distinct peaks in parallel polarisation of the incident and scattered light that are signature of collective higher order spin density excitations. This is in striking contrast to the conventional selection rule for non-resonant Raman scattering according to which spin modes can appear only in perpendicular polarisation. We predict a new selection rule for the excitations observed near resonance, namely that, apart from charge density excitations, only spin modes with positive group velocities can appear as peaks in the spectra in parallel configuration close to resonance. The results are consistent with all of the presently available experimental data.Comment: 7 pages, 2 figure

Growth study on chrysene degraders isolated from polycyclic aromatic hydrocarbon polluted soils in Nigeria

Acinetobacter anitratus, Alcaligenes faecalis, Acinetobacter mallei and Micrococcus varians were isolated from polycyclic aromatic hydrocarbon polluted soils by enrichment culture using chrysene assole carbon and energy source. Physiochemical evaluation revealed that these isolates grew well at a temperature range of 20 - 40°C, pH 6.0-8.0 but less tolerable to various salt concentrations except Micrococcus varians which grew at 1.0 to 7.5% NaCl. These organisms utilized chrysene, anthracene, naphthalene, crude oil, kerosene, diesel and engine oil as sole carbon source. None could utilize benzene, hexane, xylene, phenol and toluene as carbon sources. Growth study of the isolates on 0.1%(w/v) chrysene resulted in highest cell density of 8.8x107, 7.9x107, 6.3x106, 6.3x106 cfu/ml for A. anitratus, Alc. faecalis, A. mallei and M. varians, respectively. There was statistical significant difference (P< 0.05) in the growth of these organisms on chrysene as sole carbon and energy source when compared with non-chrysene control. This study indicates the potential of these hitherto unreported tropical bacterial strains as chrysene degraders and their use in biodegradation processes involvingpetrochemical product

Citra Perusahaan dan Kualitas Pelayanan Pengaruhnya terhadap Keputusan Menggunakan Jasa pada Sekolah Mengemudi Melati di Manado

Peningkatan kebutuhan akan ilmu pengetahuan mengakibatkan banyaknya persaingan dalam bisnis. Keberhasilan pengusaha untuk menarik dan mempertahankan pelanggan membutuhkan usaha, kerja keras dan inovasi dari pihak Perusahaan. Jika suatu Perusahaan memiliki kualitas pelayanan yang baik maka Perusahaan akan semakin memiliki banyak pelanggan dan citra dari Perusahaan itu sendiri juga akan baik sehingga menarik minat konsumen untuk memutuskan menggunakan suatu jasa. Penelitian ini bertujuan untuk mengetahui pengaruh Citra Perusahaan dan Kualitas Pelayanan terhadap Keputusan Menggunakan Jasa pada Sekolah Mengemudi Melati secara parsial dan simultan. Populasi dalam penelitian ini yaitu 43 pengguna jasa Sekolah Mengemudi Melati di Manado pada bulan Januari dan Februari dan sampel yang digunakan sebanyak 30 responden. Teknik analisis data menggunakan Analisis Korelasi dan Regresi Linear Berganda.Hasil penelitian menunjukkan bahwa secara bersama-sama atau simultan Citra Perusahaan dan Kualitas Pelayanan sebagai variabel bebas memiliki pengaruh terhadap Keputusan Konsumen untuk Menggunakan Jasa Perusahaan.Secara parsial Citra Perusahaan tidak memiliki pengaruh terhadap Keputusan Menggunakan Jasa sedangkan Kualitas Pelayanan secara parsial memiliki pengaruh terhadap Keputusan Menggunakan Jasa.Pihak Perusahaan perlu senantiasa meningkatkan Kualitas Pelayanan terhadap para konsumen sebab dengan meningkatnya Kualitas Pelayanan maka Keputusan Konsumen untuk Menggunakan Jasa juga akan semakin meningkat. Kata kunci: citra, kualitas pelayanan, keputusan pembelia

Orchid diversity in antropogenic-induced degraded tropical rainforest, an extrapolation towards conservation

The uncontrolled logging in Peninsular Malaysia and the resulting mudslides in the lowland areas have been perilous, not to just humans, but also to another biodiversity, including the wild orchids. Their survival in these highly depleted areas is being overlooked due to the inaccessible and harsh environment. This paper reports on the rescue of orchids at risk from the disturbed forests for ex-situ conservation, the identification of the diversity of orchids and the evaluation of the influence of micro-climatic changes induced by clear-cut logging towards the resilience of orchids in the flood-disturbed secondary forests and logged forests in Terengganu and Kelantan, located at the central region of Peninsular Malaysia, where the forest destruction by logging activities has been extensive. 109 orchid species belonging to 40 genera were collected from the disturbed areas. The diversity and data analyses show that the disturbed secondary forests had a higher orchid density (0.0133 plants/m2) than the logged sites (0.0040 plants/m2) as the habitat conditions were more dependable. Nevertheless, the logged forests harboured a higher diversity of orchids (H=4.50 and D=0.99) of which 97.9% were epiphytes. Eleven rare species were found along with six species endemic to Peninsular Malaysia, with two species new to science. The results highlighted the factors that allow the orchids to flourish or suffer in the disturbed forests. The logged forests had a higher ambient temperature and lower moisture level than the mud flood-disturbed and canopy-covered secondary forests. Apart from the extensive ground vegetation due to logs dragging extraction, low soil moisture and absence of leaf litter were believed to be the major attributes causing the low abundance of terrestrial orchids. The high abundance and diversity of epiphytic orchids and the large difference of their densities between the logged sites were influenced by the densities of fallen trees hosting orchid(s), disturbance-induced dryness stresses, durations of exposure to the anthropogenic-induced disturbance, and less favourable soil conditions for the terrestrial orchids