Bayesian prediction for the range with a burr distribution and a random sample size

This paper is concerned with the problem of predicting the future range with the two-parameter Burr distribution, given a sample of a random size and using the Bayesian approach. We consider two possible distributions of the random sample size and the results so obtained have been illustrated numerically, using iterative techniques and computer facilities.     

Effect of processing conditions on structural and physical properties of Cd-rich thin films of CdTe

The physical properties of CdTe thin films formed by vacuum evaporation techniques onto glass substrates were studied as a function of the processing conditions. The structure of CdTe films was examined using an X-ray diffraction (XRD) technique. The films were polycrystalline and cubic; they were grown with the (1 1 1) plane parallel to the substrate. The lattice constant (a = 0.6470 nm) was found to be smaller than that for a stoichiometric samples. This indicates the presence of residual compression stresses or excess Cd in substitutional sites. The crystallite size (10–72 nm) was found to increase with increasing substrate temperature (300–520 K). The films contained free Te which was varied with the substrate temperature. The variation of transmission within the wavelength range from 500 to 1000 nm was also investigated. It showed a band edge at about 1.5 eV. The variations of conductivity and carrier concentration with temperature were investigated. The conductivity data in the low-temperature region were analysed for variable range-hopping conduction on the basis of Mott's model. The analysis of the high-temperature conductivity data was based on Seto's model of thermionic emission. On the other hand, it was found that excess Cd increases the conductivity. However, the density of trap states near the Fermi level N(EF), was proportional to the Cd content.     

Graphite/rolled graphene oxide/carbon nanotube photoelectrode for water splitting of exhaust car solution

Graphite/rolled graphene oxide/ carbon nanotubes (G/R-GO/CNTs) was prepared and applied as a photoanode for water splitting from exhaust car solution. R-GO was prepared from graphene oxide (GO) using the modified Hummer method after settle down in solution for 2 months to roll out. The R-GO coated the graphite (G) electrode using the dip-coating method to form G/R-GO. Finally, CNTs were prepared on the G/R-GO electrode by using the chemical vapor deposition method to form G/R-GO/CNT electrode. The images of field emission scanning electron microscope show the formation of relatively homogenous and uniform R-GO with an average diameter of about 140 nm. Also, the high density of CNTs was observed with uniform diameters distribution and lengths of CNTs up to several micrometers. The values of the current density of G/R-GO/CNT electrode for water splitting are changed from 0.82 mA cm⁻² in dark to 1.50 mA cm⁻² in light. The value of incident photon-to-current efficiency was 8.4% at 470 nm. The thermodynamic parameters were calculated, in which the activation energy (E_a), enthalpy (ΔH*), and entropy (ΔS*) values were 8.1 kJ mol⁻¹, 29.9 J mol⁻¹, and 56.4 J K⁻¹ mol⁻¹, respectively.     

Design of a Proportional-Integral-Derivative Controller for an Automatic Generation Control of Multi-area Power Thermal Systems Using Firefly Algorithm

Essentially, it is significant to supply the consumer with reliable and sufficient power. Since, power quality is mea sured by the consistency in frequency and power flow between control areas. Thus, in a power system operation and control, automatic generation control (AGC) plays a crucial role. In this paper, multi-area (Five areas: area 1, area 2, area 3, area 4 and area 5) reheat thermal power systems are considered with proportional-integral-derivative (PID) controller as a supplemen tary controller. Each area in the investigated power system is equipped with appropriate governor unit, turbine with reheater unit, generator and speed regulator unit. The PID controller parameters are optimized by considering nature bio-inspired firefly algorithm (FFA). The experimental results demonstrated the comparison of the proposed system performance (FFA-PID) with optimized PID controller based genetic algorithm (GA PID) and particle swarm optimization (PSO) technique (PSO PID) for the same investigated power system. The results proved the efficiency of employing the integral time absolute error (ITAE) cost function with one percent step load perturbation (1% SLP) in area 1. The proposed system based FFA achieved the least settling time compared to using the GA or the PSO algorithms, while, it attained good results with respect to the peak overshoot/undershoot. In addition, the FFA performance is improved with the increased number of iterations which outperformed the other optimization algorithms based controller.      

Synthesis and antimicrobial testing of novel oxadiazolylbenzimidazole derivatives

OBJECTIVE: To chart the subtle neurological abnormalities in patients with asbestosis relative to possible development of cancer. METHODS: In 1979-81 a standardised neurological examination was made of 115 patients with asbestosis who carried a high risk of occupational cancer and their cancer morbidity was analysed 15 years later. RESULTS: Slight disturbances of unknown aetiology were found in the central nervous system (CNS) of 33 and in the peripheral nervous system (PNS) of 41 patients. Of these 17 had disturbances of both the CNS and PNS. This cohort was followed up to the end of 1994. During this time 47 of the patients developed cancer. Statistical analyses showed that disturbances of the CNS such as psycho-organic syndrome, cerebellar dysfunction, and motor disturbances of unknown origin were significantly associated with cancer, whereas no such association was found for peripheral neuropathy. Interaction between the radiological progression of asbestosis and disturbances of the CNS was an even stronger predictor of cancer. CONCLUSIONS: It seems that slight disturbances of the CNS are predictors of development of cancer. Whether or not these disturbances are manifestations of involvement of a paraneoplastic nervous system or some factor associated with progression of asbestosis remains open.     

Economics of off-shore/on-shore wind energy systems in Qatar

This work presents an assessment of the potential and economical feasibility of adopting off-shore/on-shore wind energy as a renewable source of energy in Qatar. An analysis is presented for the long term measured on-shore wind speed (1976–2000) at Doha International Airport. A similar analysis is presented for the measured off-shore wind speed at the Qatari Haloul Island. For the on-shore measurements, the average annual wind speed (at 20 m height) was found to be about 5.1 m/s. On the other hand, for the off-shore measurements at Haloul, the average annual wind speed was found to be about 6.0 m/s. This result indicates the suitability of utilizing small to medium-size wind turbine generators, efficiently. Such generators can be implemented for water pumping and to produce sufficient electricity to meet vital, limited needs of remote locations, such as isolated farms, which do not have access to the national electricity grid. An economical assessment is presented which takes into consideration the interest recovery factor, the lifetime of the wind energy conversion system (WECS), the investment rate and operation and maintenance costs. The results indicate that the cost of electricity generation from the wind in Qatar compares favorably to that from fossil fuel resources. The feasibility of utilizing off-shore wind turbine systems to meet the power requirements of the island of Haloul and possibly provide additional power for nearby on-shore areas is discussed.     

Failure modes and serviceability of high strength self compacting concrete deep beams

The behaviour of deep beams is significantly different from shallow beams. In deep beams, the plane section does not remain plane after deformation. The main purpose of this study is to facilitate the prediction of deep beam failure related to tensile bar and web reinforcement percentage variations. Six high strength self compacting concrete (HSSCC) deep beams were tested until failure. Strains were measured on concrete surface along mid span, tensile bar and compression strut trajectory. The load was incrementally applied and at each load increment new cracks, their widths and propagation were monitored. The results clearly show that, at ultimate limit condition, the strain distribution on concrete surface along mid-span is no longer parabolic. In deep beams several neutral axes were obtained before ultimate failure is reached. As the load increases, the number of neutral axis decreases and at failure load it reduces to one. The failure of deep beams with longitudinal tensile steel reinforcement less than that suggested by ACI codes is flexural and is accompanied by large deflections without any inclined cracks. As the longitudinal tensile steel reinforcement increases, the failure due to crushing of concrete at nodal zones was clearly observed. The first flexural crack at mid-span region was always vertical. It appeared at 25–42% of peak load. The crack length was in the range of 0.24–0.6 times the height of section. As the tensile bar percentage increases number of cracks increases with reduced crack length and crack width. The appearance of first inclined crack in compression strut trajectory is independent of tensile and web bar percentage variations.     

Blue like cheese from dried milk

A trial was made to produce Blue like cheese from both whole dry milk and non fat one. The resultant cheese was kept for ripening at 5°C for two months. Cheese made from reconstituted whole dried milks were characterized with higher moisture, salt, and protein contents and acidity than the control. Protein degradation and fat hydrolysis were found to be lower in these cheeses than the control. Organoleptically, cheese made from cow's milk was found to be superior to cheeses produced from reconstituted either non fat or whole dried milk, as regards flavour, body and texture and the distribution of P. requeforti.     

Electronic conductance in binomially tailored quantum wire

We have studied the electronic transmission properties through binomially tailored waveguide quantum wires with Dirac delta function potentials. The potential's strength is weighted according to the binomial distribution law. We have assumed that single free-electron channel is incident on the structure and the scattering of electrons is solely from the geometric nature of the problem. We have used the transfer matrix method to study the electron transmission. We found that this structure pattern allows us to have well-defined allowed conduction bands due to transmission resonance. We also found that the electronic conductance spectrum depends on the number of the Dirac delta function potential in the quantum wire. When the number of Dirac delta function potentials in the structure and their strengths are increased, both well-defined conductance bands and sharper and narrower forbidden bands are formed.