Measured Field Performance and Computer Analysis of Large-Diameter Multiplate Steel Pipe Culvert Installed in Ohio

Between 2001 and 2002, a 6.4-m (21.0-ft) diameter corrugated steel pipe culvert was erected and buried under a 22.9-m (75.0-ft) highway embankment fill in Meigs County, Ohio. This steel pipe culvert was the first of its kind to be constructed in the southeastern region of Ohio. The culvert structure was selected by the Ohio Department of Transportation over an alternative of a 5 million conventional bridge structure, because it would cost about $3.4 million less. The field performance of the culvert was monitored by measuring the pressure distribution around the pipe, as well as the deflections of the pipe culvert during and after construction. The culvert study also included comparing measured field performance with numerical predictions given by the finite-element computer program CANDE-89. CANDE-89 with the slotted joint option had a limited ability to simulate the actual field behavior of the large-diameter multiplate culvert structure, especially in the earlier stages of construction.     

Proposal of nonlinear stability indices of power swing oscillation in a multimachine power system

In this paper, we propose new nonlinear stability indices for multimode oscillations in power systems by using normal form analysis. One of the indices indicates the characteristics of damping factor with regard to its amplitude change, and the other indicates the stability region for each oscillation mode. We could obtain more detailed information on the stability of power system by using the proposed indices together with eigenvalues in comparison with eigenvalue analysis. We show the validity of the proposed indices by numerical simulation in a multimachine power system. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(4): 16–24, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20070     

Fabrication of Shape-Controlled Au Nanoparticles in a TiO2-Containing Mesoporous Template Using UV Irradiation and Their Shape-Dependent Photocatalysis简

A SiO_2-TiO_2 template with ordered tubular mesochannels has been prepared by the sol—gel method.Au nanorods are deposited in the tubular mesochannels of the SiO_2—TiO_2 template,and the shape of Au is changed from nanorods to nanospheres by ultraviolet irradiation during thermal deposition.The photocatalytic activity of mesoporous SiO_2—TiO_2 with/without Au nanorods/nanospheres is evaluated.Deposition of Au in the mesoporous SiO_2—TiO_2 template enhances the photocatalysis of TiO_2.Interestingly,the sample containing Au nanorods exhibits higher photocatalytic activity than that with Au nanospheres.Photocatalysis by exciting surface plasmon resonance is not detected in the composite samples regardless of the shape of the deposited Au nanoparticles.     

Performance and physicochemical properties of α-sulfo fatty acid methyl esters

The detergency properties of α-sulfonated fatty acid methyl esters (α-SFMe) were evaluated and compared to those of conventional anionic surfactants by using a model heavy-duty detergent formulation. Several physicochemical properties of surfactants were measured to investigate the effective factors on detergency. α-SFMe showed good detergency performance under various washing conditions. These results were considered to correlate well with the good adsorption behavior on oils and dispersing capabilities for particles, as well as with the good solubilization capacity. Solubilization behavior of α-SFMe is discussed in relation to micelle properties. It is suggested that α-SFMe can form suitable micelles for solubilizing polar oils advantageously, due to its bulky hydrophilic group.     

Thermal stability and behavior of platelet-shaped SBA-15 containing Zr

SBA-15 with a platelet shape, containing Zr(IV), (Zr-SBA-15) was prepared to characterize its thermal stability and thermal behavior in comparison with conventional, rod-shaped SBA-15. The small angle X-ray diffraction (SAXRD) lines of Zr-SBA-15 and SBA-15 disappeared at 1,373 and 1,273?K, respectively. The pore diameter of the Zr-SBA-15 was almost constant from 773 to 1,073?K and decreased above 1,173?K, whereas the SBA-15 pore diameter decreased with increasing calcination temperature from 773 to 1,173?K. Therefore, the thermal stability of the Zr-SBA-15 was higher than that of SBA-15. Zr(IV) distributed within the framework prevents the pores from shrinkage by heating, and the Zr(IV) forms a ZrO₂ crystalline phase above 1,273?K. When calcined at 1,873?K, the Zr-SBA-15 mesostructure collapsed while maintaining its hexagonal platelet shape. The collapse of the mesostructure at 1,373?K, caused the Zr-SBA-15 to shrink in the width direction by approximately 40% compared with that calcined at 773?K, although the dimension hardly changed in the thickness direction.     

Synthesis and mechanical properties of porous alumina from anisotropic alumina particles

A porous alumina body was synthesized from anisotropic alumina particles (platelets). The uniaxial pressure in fabricating the green compact body had an influence on the relative density of the alumina body after heating. When green compacts, which had been uniaxially pressed at 1 and 3 MPa, were heated at 1400 °C for 1 h, the relative densities of the resulting alumina bodies were 25.0% and 35.5%, respectively. The compressive strength of compacts that were uniaxially pressed at 1 and 3 MPa were 0.8 and 4.3 MPa, respectively. In an attempt to increase the compressive strength of these porous alumina bodies, aluminum nitrate and magnesium nitrate solution treatments were performed, followed by reheating to 1400 °C for 1 h. When a 0.5 mol/l aluminum nitrate solution was used, the compressive strength of the porous alumina body uniaxially pressed at 1 MPa changed from 0.8 MPa (without solution treatment) to 1.5 MPa. Furthermore, when 0.1 mol/l magnesium nitrate solution was used, the compressive strength of the porous alumina increased to 1.7 MPa. Thus, solution treatment of the porous alumina body had a strong positive effect on its mechanical strength.     

An update on the CNS actions of TRH and its analogs

This brief review will discuss the recent literature on several of the central actions of TRH and its analogs. The most prominent of these actions include: (1) the arousal or analeptic effect in drug narcotized animals or in concussion models; (2) the reversal of cognitive deficits produced by various drugs or procedures, and (3) the improvement of several neurological deficits produced in animal models of spinal and/or cerebellar injury. The mediation of these TRH effects by neurotransmitters is discussed. While little has been published on the human neuropsychopharmacology of TRH, and especially of its analogs, the future holds considerable therapeutic promise for these interesting drugs.     

Expression of vascular endothelial growth factor and its receptors in rats with protein-overload nephrosis

BACKGROUND: Based on the fact that vascular endothelial growth factor (VEGF) increases vascular permeability, it is speculated that VEGF might be involved in the development of proteinuria, although this remains unconfirmed. The production and site of action of VEGF remains unclear in nephrotic renal diseases. METHODS: Non-radioactive in situ hybridization was performed to examine the expression of VEGF mRNA and its receptors, flt-1 and KDR/flk-1, in a rat model of nephrosis induced by intraperitoneal injection of bovine serum albumin (BSA). Saline injected rats were served as control animals. RESULTS: Neither morphological changes nor deposition of immunoglobulin or complement were observed in our model. Proteinuria developed, reaching a maximum level in rats injected with BSA for 3 days, followed by persistent proteinuria until day 14. The expression of mRNA for VEGF and the two receptors was markedly upregulated in glomeruli of BSA-induced nephritis compared with the control group. VEGF mRNA was localized in glomerular cells, including cells in mesangium, visceral and parietal epithelial cells. In contrast, flt-1 mRNA and KDR/flk-1 mRNA were expressed on glomerular endothelial cells and cells in mesangium. The ratio of glomerular cells positive for VEGF mRNA and its receptors mRNA increased proportionately with the severity of proteinuria. Immunohistochemistry for ED-1 and proliferating cell nuclear antigen showed no significant increase in infiltrating macrophage or cellular proliferation. Conclusions: Our results suggest that altered glomerular expression of VEGF and its receptors is not associated with proliferation of endothelial cells, but rather with proteinuria in BSA-induced nephritis in rats. VEGF may play a different role in different renal diseases.     

Investigation on force transmission of direct-drive thorax unit with four ultrasonic motors for a flapping microaerial vehicle

We fabricated a trial version of a thorax unit with four ultrasonic motors (USMs) to simulate a dragonfly-scale flapping micro aerial vehicle (MAV). Each wing was directly driven by a two-degree-of-freedom (2-DOF) transmission. An in-house tiny standing-wave USM capable of bidirectional rotation, which weighs just 0.13 g, was employed on trial. The transmission of the thorax unit converts the two USM rotations into strokes and flip motions of the wing. By implementing two 70-mm-long wings, we fabricated a prototype of a 4-DOF MAV and tested its performance. In a lift-compensated situation, upward, forward, and backward movements of the MAV were obtained. The flapping angular velocity was discussed based on quasi-static wing aerodynamics and was accountable for the motor power. Although the power of the USM should be improved, the quick wing drivability, adequate power transmission on the thorax unit, and potential of a 0.2 W motor power in a unidirectional-type USM promise the viability of a direct-drive multi-DOF dragonfly-scale MAV.     

An investigation of strain hardening and creep in an AI-6061/AI2O3 metal matrix composite

Experiments were conducted to compare the influence of temperature on the flow and strain-hardening characteristics of an Al-6061 metal matrix composite, reinforced with ∼20 vol pct of Al₂O₃-based microspheres, with the unreinforced monolithic alloy. At room temperature, the yield stresses and the strain-hardening rates are higher in the composite material in the asquenched condition and after aging at 448 K for periods of time up to 300 hours. The 0.2 pct proof stress and the strain-hardening rate decrease with increasing temperature in both materials, but the rate of decrease is faster in the composite so that the unreinforced monolithic alloy exhibits higher yield stresses and strain-hardening rates at temperatures in the vicinity of 600 K. Under conditions of constant stress at high temperatures, the composite exhibits both a higher creep strength than the monolithic alloy and higher values for the stress exponents for creep. Formerly Visiting Scholar, Kyushu University, is Associate Professor, Department of Metallurgy, Xian Institute of Metallurgy and Construction Engineering, Xian 710055, People’s Republic of China.