Effect of corrugated plates in an in-phase arrangement on the heat transfer and flow developments

In the present study, the numerical results of the heat transfer and flow developments in the corrugated channel under constant heat flux conditions are presented. The test section is the channel with two opposite corrugated plates which all configuration peaks lie in an in-phase arrangement. The corrugated plates with three different corrugated tile angles of 20°, 40°, and 60° are tested with the height of the channel of 12.5 mm. The model was simulated for the Reynolds number and heat flux in the ranges of 400–1600 and 0.5–1.2 kW/m², respectively. The flow and heat transfer developments are simulated by using the k-ε standard turbulent model. A finite volume method with the structured uniform grid system is employed for solving the model. The predicted results are validated by comparing with the measured data. There is reasonable agreement from the comparison between the numerical data and experimental data. Effects of relevant parameters on the heat transfer and flow developments are discussed. Due to the breaking and destabilizing in the thermal boundary zone, the corrugated surface has significant effect on the enhancement of heat transfer and pressure drop.     

Heat transfer and flow characteristics in the hard disk drive tester

The numerical results of the heat transfer and flow characteristics in the hard disk drive tester are presented. The testing of the hard disk drive with keeping drives within the normal and high temperatures in the tester has been introduced as one of the manufacturing processes of the hard disk drive. The cooling air entering the tester is induced by the 10 axial fans into the tester and is impinged the hard disk drives and then discharged to the atmosphere. The k–ε standard turbulent model is applied to analyze the model. The results obtained from the model are verified by comparing with the measured data. Reasonable agreement is obtained from the comparison between the results obtained from the model and those from the experiment. The numerical results show that the flow and temperature distribution of cooling air are not uniformed. Which none-uniform temperature and accumulated heat are significantly factors to the failure of the hard disk drives. The results of this study are of technology importance for the efficient design and/or approved hard disk drive tester to decrease hard disk drive failure.     

Purification and Characterization of Organic Solvent and Detergent Tolerant Lipase from Thermotolerant Bacillus sp. RN2

The aim of this study was to characterize the organic solvent and detergent tolerant properties of recombinant lipase isolated from thermotolerant Bacillus sp. RN2 (Lip-SBRN2). The isolation of the lipase-coding gene was achieved by the use of inverse and direct PCR. The complete DNA sequencing of the gene revealed that the lip-SBRN2 gene contains 576 nucleotides which corresponded to 192 deduced amino acids. The purified enzyme was homogeneous with the estimated molecular mass of 19 kDa as determined by SDS-PAGE and gel filtration. The Lip-SBRN2 was stable in a pH range of 9-11 and temperature range of 45-60 °C. The enzyme was a non metallo-monomeric protein and was active against pNP-caprylate (C8) and pNP-laurate (C12) and coconut oil. The Lip-SBRN2 exhibited a high level of activity in the presence of 108% benzene, 102.4% diethylether and 112% SDS. It is anticipated that the organic solvent and detergent tolerant enzyme secreted by Bacillus sp. RN2 will be applicable as catalysts for reaction in the presence of organic solvents and detergents.     

Study on the heat-transfer characteristics and pressure drop in channels with arc-shaped wavy plates

The heat-transfer characteristics and pressure drop in a channel with arc-shaped wavy plates are presented. The test channel with two opposite wavy plates, whose peaks are in-phase or out-of-phase, are tested under constant wall heat flux conditions. The experiments are made for the Reynolds number and heat flux in the ranges 1500–2500 and 0.5–1.2 kW/m², respectively. The effects of relevant parameters on the heat-transfer characteristics are considered. A turbulent mathematical model is employed to simulate the temperature and velocity distributions. The predicted results are verified by comparing with measured data, and reasonable agreement is obtained. Due to the onset and growth of the recirculation zones, the convective heat transfer in the channel with wavy plates is higher than that with flat plates.     

Temperature distribution of read/write head soldering with ribbon cable of HDD

In the present paper, the temperature distribution of the read/write head soldering with the ribbon cable of the HDD is presented. The soldering of the actuator/connector with the ribbon cable can be performed either by manual or semi-automatic process which has been introduced as one of the manufacturing processes of the HDD. Finite element analysis is applied to analyze the model. The properties of the soldering ball and boundary conditions have significant effects on the thermal stress and localized heat in the soldering process that cause the failure of the ribbon cable of the HDD. The results of this study are of technological importance for the efficient design and/or approval of the soldering HDD process to reduce yield loss of the hard disk drive.     

Laminar convective heat transfer and pressure drop in the corrugated channels

The results of the heat transfer characteristics and pressure drop in the corrugated channel under constant heat flux are presented in the present study. The test section is the channel with two opposite corrugated plates which all configuration peaks lie in an in-line arrangement. The corrugated plates with three different corrugated tile angles of 20°, 40°, and 60° are tested with the height of the channel of 12.5 mm. The experiments are done for the heat flux and the Reynolds number in the ranges of 0.5–1.2 kW/m² and 500–1400, respectively. Effect of relevant parameters on the heat transfer characteristics and pressure drop are discussed. Due to the presence of recirculation zones, the corrugated surface has significant effect on the enhancement of heat transfer and pressure drop.     

Development of cold‐hot water dispenser with thermoelectric module systems

In the present study, the results of a cold‐hot water dispenser with a thermoelectric module system (TMS) are presented. The cold‐hot water dispenser with thermoelectric module system consists of a cold water loop, a hot water loop, a coolant loop, and a thermoelectric module. The thermoelectric cooling and heating modules consist of four and two water blocks, nine and three thermoelectric plates, respectively. The cooling and heating capacities obtained from the cold‐hot water dispenser with TMS are compared with those from a conventional cold‐hot water dispenser with a compression refrigeration system (CRS). As compared with the conventional cold‐hot water dispenser with CRS, the cold‐hot water dispenser with TMS can be operated at the minimum cold water temperature of 10 to 13°C and the maximum hot water temperature of 65°C. The obtained results are expected provide guidelines to design cold‐hot water dispensers with TMS.     

Experimental Study of the Effect of the Helical Ribs in a Spirally Coiled Tube on the Friction Reactor and the Nusselt Number of a Nanofluid Flow in it

Journal of Engineering Physics and Thermophysics - The effect of the centrifugal force arising in a spirally coiled tube with helical ribs on the heat transfer in the fluid flow in it was...     

Cloning, Expression, and Characterization of Thermotolerant Manganese Superoxide Dismutase from Bacillus sp. MHS47

A superoxide dismutase gene from thermotolerant Bacillus sp. MHS47 (MnSOD47) was cloned, sequenced, and expressed. The gene has an open reading frame of 612 bp, corresponding to 203 deduced amino acids, with high homology to the amino acid sequences of B. thuringiensis (accession no. EEN01322), B. anthracis (accession no. NP_846724), B. cereus (accession no. ZP_04187911), B. weihenstephanensis (accession no. YP_001646918), and B. pseudomycoides. The conserved manganese-binding sites (H28, H83, D165, and H169) show that MnSOD47 has the specific characteristics of the manganese superoxide dismutase (MnSOD) enzymes. MnSOD47 expressed an enzyme with a molecular weight of approximately 22.65 kDa and a specific activity of 3537.75 U/mg. The enzyme is active in the pH range 7-8.5, with an optimum pH of 7.5, and at temperatures in the range 30-45 °C, with an optimum temperature of 37 °C. Tests of inhibitors and metal ions indicated that the enzyme activity is inhibited by sodium azide, but not by hydrogen peroxide or potassium cyanide. These data should benefit future studies of MnSODs in other microorganisms and the biotechnological production of MnSOD47, and could also be used to develop a biosensor for the detection of antioxidants and free radical activity. In the future, this basic knowledge could be applicable to the detection of cancer risks in humans and therapeutic treatments.     

Quantitative Analysis of X-ray Lithographic Pores by SEM Image Processing

Arrays of regular macropores in electronic, magnetic, photonic and sensing devices can be patterned by X-ray lithography. Such structures inevitably contain some irregularity and require time-consuming pattern inspections. In this work, a pattern inspection by intensity-based digital image processing procedure is proposed and tested on scanning electron microscopy images of porous SU-8 polymer resist. The Otsu’s thresholding converted grayscale to binary images and the closing morphology algorithm was applied to reduce noise in the images. The Canny edge detector was used to identify the contour of each pore by detecting abrupt intensity changes in the binary image. Pores were detected and their sizes were subsequently evaluated. The morphological distributions analyzed by this procedure are comparable to those carried out by the one-by-one human inspection.