Tensile load and the metabolism of anterior cruciate ligament cells

It generally is recognized that tensile load plays a major role in maintaining the homeostasis of the anterior cruciate ligament fibers, but its detailed mechanism remains a matter of controversy. The effect of cyclic tensile load on the metabolism of the anterior cruciate ligament were investigated experimentally using cultured cells from the anterior cruciate ligament of rabbits. Using culture plates with flexible rubber bases, a cyclic tensile load was applied to the cultured cells for 24 hours, and the changes in shape, alignment, and metabolism of the cells were analyzed. Under the cyclic tensile load, the shape of the cells from the anterior cruciate ligament changed to spindle and aligned perpendicularly to the direction of the tensile load. The cyclic tensile load also caused an increase in collagen synthesis by the cells from the anterior cruciate ligament, which was predominant in Type I. The cells from the synovium showed similar changes in shape and alignment under the cyclic tensile load, but no significant change was observed in cell metabolism. These observations suggest that the application of cyclic tensile load on the anterior cruciate ligament cells is an important factor in the regulation of collagen synthesis in the anterior cruciate ligament.     

Rapid Vapor Grown Carbon Fiber Production Using the Intermittent Liquid Pulse Injection Technique

Three series of experiments were conducted to collect information for the design of a commercial scale reactor for the production of low cost vapor grown carbon fibers (VGCFs). Firstly, the effects of reaction conditions on the yield of vapor grown carbon fibers were investigated using the newly developed liquid pulse injection technique. The examined conditions were the flow rate of the carrier gas, and the amount of the catalyst source injected into the reactor as a liquid pulse. Yields up to 40% were attained under optimized conditions. Secondly, VGCFs were continuously produced by intermittently injecting the catalyst source into the reactor (intermittent liquid pulse injection technique), and the effect of the intervals of the injections on the amount of VGCFs obtained was also investigated. VGCFs were successfully obtained using this method. Finally, the growth sequences of VGCFs were investigated using benzene, toluene and xylene as the carbon source. VGCFs were obtained from each carbon source     

ATM transmissions of microprocessor-based current differentialteleprotection signals

This paper describes prudent considerations for applying asynchronous transfer mode (ATM) transmissions, which can provide broadband and multimedia communications as well as flexible, efficient and wide-area networks, to microprocessor-based current differential teleprotection systems. As both functions of current data transmission and simultaneous sampling among remote terminals are required for the telecommunication systems, measures against cell losses and cell delay variations in ATM network elements such as terminal adapters and switches are proposed for the present delay-sensitive teleprotection systems. Allowable system configurations are examined under severe delay constraints in Japan. A new concept of an ATM-native teleprotection system employing time synchronous systems such as GPS is also proposed     

High Temperature Oxidation Behaviour of High Al Content Ferritic and Austenitic Stainless Steels With and Without Rare-Earth Element Addition

The oxidation behaviour of austenitic and ferritic alloys containing 4% Al and rare-earth element addition of (La?+?Ce) has been investigated, and comparisons made to an austenitic alloy with no such addition. The alloys were all found to exhibit good oxidation resistance; although, such resistance was highest when the alloy contained rare-earth elements. The addition led to a reduction in the amount of scale spalling. The scales formed after 10 and 100?h at 1,000?°C were examined using transmission electron microscopy and found to have bi-layered microstructures. The dislocation density and an amount of distortion in the scale were found to differ, depending on the absence or presence of (La?+?Ce) in the metal. It was observed that the outer-to-inner layer thickness ratio changed with time and the rare-earth element addition promoted growth of the inner layer relative to the outer layer. Analysis of the scale compositions demonstrated an apparent synergistic relationship between the effects of the rare-earth element addition and the degree to which iron is incorporated within the scales. The results are discussed in relation to the relative oxidation performance of the austenitic and ferritic alloys.     

A control scheme for a three‐phase current source inverter in utility interactive photovoltaic system

A novel PWM control scheme for a three‐phase current source inverter of a photovoltaic (PV) generation system connected to a utility is proposed. The PV‐array output power can be adjusted by controlling the modulation factor in the proposed PWM pattern. The harmonic components of the output currents can be decreased sufficiently to satisfy the requirements of the Interactive Guidelines. Furthermore, a new Maximum Power Point Tracking control is proposed. The inverter output current should be detected, and the modulation factor may be controlled so as to obtain the maximum effective current. The inverter output power can be maintained at the maximum power point despite fluctuations of panel temperatures, insolation levels, and system voltages. © 2001 Scripta Technica, Electr Eng Jpn, 135(1): 43–55, 2001     

Diode-pumped Nd:YAG laser producing 122-W CW power at 1.319 μm

A high-power diode-pumped Nd:YAG laser oscillating at a wavelength of 1.319 μm is reported. A 122-W CW laser beam with an M2 factor of 35 has been achieved with an optical efficiency of 19.6%. The lasing characteristics, including thermal lensing, at 1.319 μm are compared with those at 1.06 μm. Under lasing conditions, the focal length of thermal lensing at 1.319 μm decreases by 25% and increases by 15% at 1.06 μm with respect to the nonlasing conditions. Based on the experimental results, the heat dissipation in an Nd:YAG rod is discussed with reference to nonradiative transitions from the upper laser level     

Thickness uniformity of HDPE blown film: Relation to rheological properties and density

Previous work has elucidated that the wall slip velocity and viscosity of polymer melts influence the thickness uniformity of blown film. The present study investigates the effects of the stress dependence of wall slip, the shear thinning and the density on the uniformity. We have prepared high‐density polyethylenes with a variety of molecular weight distributions, which have different rheological properties. Examination of the thickness uniformity of their blown film has shown that the uniformity is correlated with wall slip velocity, the stress dependence of the velocity, melt viscosity, shear thinning and density; the coefficient of the correlation is determined to be 0.990. The reason why the stress dependence of wall slip and the shear thinning affect the uniformity is explained in terms of polymer melt flow behavior in a die, while the effect of density is interpreted considering bubble fluctuation in the blow‐up process. Polym. Eng. Sci. 44:965–972, 2004. © 2004 Society of Plastics Engineers.