Effect of Boronizing on Operating Stability of Steel AISI 304L under Erosion Impact of Hard Particles

Metal Science and Heat Treatment - The effect of solid boronizing at 950°C for 2 and 4 h on the phase composition, microstructure, hardness and abrasive wear of steel AISI 304L is studied...     

Comparison of Two Drying Schedules for European Hophornbeam (Ostrya carpinifolia Scop.) Lumber

Two types of conventional kiln-drying schedules (mild and harsh) based on moisture content (MC) were compared with regard to time, drying quality, and energy cost. The results were evaluated according to the classification of the European Drying Group. Proper drying periods of mild and harsh schedules were found to be 550 and 514 h, respectively. Evaluations in terms of drying quality indicated that better results were achieved with the mild schedule, especially when comparing drying defects and final MC. From an energy efficiency point of view, the harsh schedule, by saving 36 h of drying time, reduced electricity by 594 KWh and was therefore found to be $65 more profitable in this trial.     

The musculoskeletal system complaints of office workers at a vehicle production factory

This study aimed to determine the prevalence of and factors contributing to musculoskeletal system complaints (MSC) in office workers of a vehicle production factory and absenteeism due to these complaints. A total of 86.2% (n = 333) of the workers completed the survey. Of the workers, 73 (21.9%) were women, and 260 (78.1%) were men, and the mean age was 36.9 ± 8.75 years. The majority of the personnel had more than one symptom with a prevalence of 80.8%. The most frequently observed discomfort was tension and pain in the back muscles (58.6%) and in the neck muscles (58.3%), followed by low back pain (41%) and shoulder pain (30.3%). Pain in the shoulders, neck, and the back and pain and numbness in the fingers were statistically significantly more prevalent in employees who spent more than 5 hours per day performing desk work. Furthermore, all of the complaints, excluding pain in the elbows and knees, were statistically significantly more common in the women. When each complaint and the effects of contributing risk factors were analyzed by logistic regression analysis, pain in the shoulders, neck, and back; pain that spread to the arms; and pain in the fingers were correlated with longer work hours and the female gender (p < 0.05). The number of employees who had used sick leave within the past year due to MSCs was 11.7%. In conclusion, duration of work hours, frequency of breaks, and gender were determined as the most important risk factors in computer users regarding MSCs. © 2011 Wiley Periodicals, Inc.     

Noise exposed of the operators of combine harvesters with and without a cab

A considerable number of the combine harvesters in Turkey are rather old and used without cabs resulting in unhealthy working conditions for their operators. Noise is one of the detrimental factors. This study deals with determining and comparing the noise exposed on the operators of the combines with and without a cab used for wheat harvesting in Turkey. The sound pressure levels (dB) at octave band center frequencies (31.5–8000 Hz) and the sound levels (dBA) at the ear level of the operators were measured on 37 different combine harvesters with four different makes and different years from 1976 to 2001. Fifteen of the combines were without a cab, another 15 had original cabs while remaining seven combines had cabs mounted on them after manufacturing.

The sound pressure levels were in a decreasing trend from the lower frequencies to higher frequencies. This trend was more noticeable for the combines with original cab and with the cab mounted after manufacturing compared to the ones without cab. The use of a cab was more effective in the insulation of the noise at the medium and higher frequencies, which have more bothersome effect compared to the lower frequencies. The sound pressure levels were 75–102 dB and 46–89 dB at low (31.5–500 Hz) and high (500–8000 Hz) frequencies for all combines, respectively. The sound pressure levels at the frequency of 4000 Hz at which the human ear is most sensitive were 6–17 dB lower for the combines with the cabs mounted after manufacturing and 9–28 dB lower for the ones with the original cabs compared to the combines without cab. The sound levels were 85–90, 81–83, and 76–81 dBA for the combines without cab, with cab mounted after manufacturing, and with original cab, respectively.

The study showed that the use of a cab was useful in the insulation of the noise, particularly at higher frequencies. In addition, it protects the operator from the factors having detrimental effects on the working efficiency such as high temperature and dusty environment. The authors strongly recommend mounting of a cab on to the combines currently being used without a cab in rental system in Turkey to provide healthy working conditions for their operators.     

Experimental study of a micro-scale sloped solar chimney power plant

Journal of Mechanical Science and Technology - Solar chimney power plants (SCPP) are structures that have the potential to generate a significant amount of electrical energy without harming the...     

Unsaturated flow phenomena in porous medium as in a trickling filter

The relationship between substrate removal efficiency and dispersion characteristics of biological filters was investigated. Flow measurements were made using tap water and a synthetic feed solution. The importance of changes in fluid regime with regard to the simultaneous transport and reaction within the biological filter was demonstrated. The effect of drop formation and breakage of liquid jets on substrate utilization was shown.     

Performance evaluation of a submerged membrane bioreactor for the treatment of brackish oil and natural gas field produced water

Produced water, which is co-produced during oil and gas manufacturing, represents one of the largest sources of oily wastewaters. Therefore, treatment of this produced water may improve the economic viability and lead to a new source of water for beneficial use. In this study a submerged hollow fiber membrane bioreactor (MBR) has been studied experimentally for the treatment of brackish oil and natural gas field produced water. This type of wastewater is also characterized with relatively moderate to high amount of salt, oil and total petroleum hydrocarbons (TPH). However, the bacteria which are growing in conventional activated sludge and MBR cannot survive at these strict conditions, therefore acclimation of the bacteria is of vital importance. The performance of the biological system, membrane permeability, the rate and extent of TPH biodegradability have been investigated under different sludge age and F/M ratios. The results obtained by gas chromatography analyses showed that the MBR system could be very effective in the removal of TPH from produced water and a significant improvement in the effluent quality was achieved.     

Effect of weathering on the geomechanical properties of the Miocene basalts in Malatya,Eastern Turkey

Miocene volcanic rocks are widely exposed in the eastern Taurids, Turkey. The geomechanical properties and weathering degree of the Middle–Upper Miocene basalts were determined at the Boztepe dam site in Malatya, eastern Turkey. An engineering geology map of the Boztepe dam site was made and the joint sets and the degree of weathering determined in the field. The degree of weathering and RQD values were obtained on some 1,195 m of core which was then compared with a series of geomechanical tests including unit weight, porosity, water absorption, uniaxial compressive strength and compressive wave velocity. The geomechanical properties were compared with the weathering classifications of ISRM (Rock characterization, testing and monitoring, p 211, 1981) and Kilic (Environ Eng Geosci 4:475–483, 1999)      

Investigation of UV and I–V characteristics of high refractive index polymer thin film for optoelectronic applications

In this study, high refractive index polymer (HRIP) [poly(pentabromobenzyl methacrylate-co-glycidyl methacrylate)] was investigated to obtain its optical and electrical performance for optoelectronic applications. UV characteristics of the polymer in solution of tetrahydrofuran were obtained and optical band gap energy of the polymer was calculated as 3.8 eV. I–V characteristics of the polymer were investigated after HRIP thin film was prepared using spin coating technique. The electrical parameters such as barrier height Φ_Bo, ideality factor n and reverse saturation current I_o were extracted from the forward biasing I–V characteristics. At the same time, series resistance R_s and Φ_Bo were determined by using a modified Norde function combined with conventional forward I–V method.     

Monte Carlo Simulations of 17.9–22.3 MeV Energetic Proton Irradiation Effects on bcc-Zirconium Fusionic Materials

Advanced fusion structural materials (FSMs) have impact role in terms of efficiency of nuclear energy production. Besides engineering and design of fusion reactors, radiation durability of FSMs is another valuable issue that cannot be ignored. 17.9–22.3 MeV proton irradiation of bcc-Zirconium Fusion Structural Material was evaluated by using Monte Carlo based simulation tools. Total binary reaction cross sections were respectively calculated as 1167.6 and 1273.92 mb for 17.3- and 22.3 MeV proton energies via TALYS-1.6 version. Additionally, residual production cross sections and total particle production cross sections were obtained and analyzed by the TALYS code. Radiation damage parameters as Displacement Per Atom (DPA) and Stopping Power (SP) were studied by SRIM-2013 version. FLUKA 2011.1 used for only DPA calculations and making a complete comparison with the other calculation results. SP and Number of Secondaries were found by using GEANT4.10.p.04 version simulations. Natural Zr(p,x) reactions were studied in the given energy values in the plane of reaction probability and radiation damage calculations.