Effects of species and moisture content on penetration of liquid in laser incised lumber by the passive impregnation method

Penetration of liquid by passive impregnation method for Douglas-fir (Pseudotsuga menziesii Franco), sugi (Cryptomeria japonica D. Don) and Japanese larch (Larix leptolepis Gordon) was studied. Effects of initial moisture content of sugi (16, 43 and 70% moisture content) on liquid penetration were also studied. Dried Douglas-fir (mc=14%) and sugi (mc=16%), and green Japanese larch (mc=45%) and sugi (mc=70%) were treated by passive impregnation method for penetration analysis. It was observed that dried sugi had the highest level of liquid penetration both in length (170 mm) and width (8 mm) for all measured sections followed by green sugi, green Japanese larch and dried Douglas-fir. In case of different initial moisture content, the highest absorption (624 kg/m³) and penetration (maximum 87 and 96% at cross and longitudinal surfaces, respectively) was observed for sugi having the lowest initial moisture content under the same passive impregnation conditions. Absorption and penetration decreased with the increase of initial moisture content for sugi. These results could help in designing incising pattern and density, as well as solving the problems related to high initial moisture content of wood for passive impregnation.     

High-performance polymer photovoltaic devices with inverted structure prepared by thermal lamination

Use of a lamination process for the introduction of Au electrode, instead of conventional metal evaporation, improved the power conversion efficiency (PCE) of inverted-structure photovoltaic devices from 1.6% to 2.6% based on a bulk heterojunction of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C₆₁ butyric acid methyl ester (PCBM). X-ray photoelectron spectroscopy indicated that a thin layer of P3HT is spontaneously formed at the air/polymer blend layer interface during the spin-coating process. It is suggested that the vacuum-evaporated gold could destroy the surface-segregated thin layer of P3HT, while the lamination process preserves the surface structure working as an electron-blocking layer. The insertion of a PEDOT:PSS layer, between the metal electrode and polymer layer, in the lamination process further improved the PCE to 3.3% with a short-circuit current density of 9.94 mA cm⁻², an open-circuit voltage of 0.60 V, and a fill factor of 55% under AM1.5 100 mW cm⁻² irradiation.     

FDTD simulation of nonlinear ultrasonic pulse propagation in ESWL using equations including Lagrangian

A new FDTD algorithm is proposed for analyzing ultrasonic pulse propagation in the human body, a problem connected with ESWL (extracorporeal shock wave lithotripsy). In this method, we do not use plane wave approximation but directly employ the original equations, taking into account the Lagrangian to derive new FDTD algorithms. This method is applied to an experimental setup and its numerical model that resembles an actual treatment situation in order to compare the sound pressure distributions obtained numerically with those obtained experimentally. The present method is shown to give clearly better results than the earlier method, from the point of view of the numerical reappearance of a strongly nonlinear waveform. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 29–36, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20819     

Exaggerated urinary excretion of aquaporin-2 in the pathological state of impaired water excretion dependent upon arginine vasopressin

The present study was undertaken to determine whether urinary excretion of aquaporin-2 (UAQP-2) is of value to diagnose the pathological state of water retention and hyponatremia. UAQP-2 under ad libitum water drinking was 429 fmol/mg creatinine in the patients with water retention, a value significantly greater than that of 153 fmol/mg creatinine in the normal subjects. An acute oral water load test (20 mL/kg BW) was performed in 7 normal subjects (22-25 yr old) and 10 patients with water retention and hyponatremia (55-75 yr old). The percent excretion of the water load was only 30% in the patient group compared with 70% in the control group (P < 0.01). In the control group, minimal urinary osmolality was as low as 131 mosmol/kg H2O, which was responsible for the decrease in plasma arginine vasopressin (AVP) levels after the reduction in plasma osmolality. In the patient group, minimal urinary osmolality was 320 mosmol/kg H2O, and free water clearance remained below 0.6 mL/min after the water load. This impaired water excretion was consistent with the nonsuppressible levels of plasma AVP despite hypoosmolality. The nadir of UAQP-2 was obtained at 60-90 min. The minimal UAQP-2 was reduced to 284 fmol/mg creatinine, a value significantly greater than that of 76 fmol/mg creatinine in the control group. Similar results were obtained in the 6 patients with hypopituitarism, who had impaired water excretion and marked hyponatremia. Water excretion was totally normalized after the replacement of hydrocortisone (excretion of water load, 31% vs. 102%; P < 0.01). Hydrocortisone replacement also significantly reduced the minimal UAQP-2 from 225 to 49 fmol/mg creatinine after the acute oral water load, a value comparable to that in the control subjects. These results indicate that UAQP-2 is a potent marker to diagnose the pathological state of impaired water excretion and hyponatremia, dependent upon AVP, in patients with water retention and hypopituitarism.     

微导通孔的电镀填孔技术

本文主介绍了电镀填孔技术,并探讨了DC和PPR电镀填孔技术的优缺点和影响填孔效果的相关因素。     

Short‐span seeking control of hard disk drive with vibration suppression PTC

In a short‐span seeking‐mode of hard disk drives, the resonance modes are getting crucial obstruction to meet the demand on high‐speed data access. In this paper, a novel vibration suppression perfect tracking control (PTC) method is proposed based on controllable canonical realization. In the proposed method, it is assumed that the plant is modeled as the rigid and primary resonance mode. By using this model, the feed forward controller is designed with PTC by multirate sampling control in order to suppress the primary vibration. Additionally, the higher‐order resonance vibration is attenuated by using the trajectory MHVT. The proposed method achieved 16% faster seeking than MPVT, a conventional method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(1): 66–72, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20546     

N-Alkylation of chitin and some characteristics of the novel derivatives

Summary Introduction of simple alkyl groups at the C-2 nitrogen of chitin and some properties of the resulting N-alkyl-chitins have been examined. Chitosan was fully deacetylated and treated with three kinds of aldehydes, formaldehyde, acetaldehyde, and pentanal. The Schiff bases of chitosan, whose extents of substitution were dependent on the amount of aldehydes, were reduced with sodium cyanoborohydride to N-alkylated chitosans. The N-alkyl-chitosans were then transformed into the corresponding N-alkyl-chitins by acetylation with acetic anhydride followed by transesterification to remove partly formed O-acetyl groups. The resulting N-methyl-, ethyl-, and pentyl-chitins were amorphous and showed improved affinity for organic solvents. Received: 13 December 2001/Revised version: 11 January 2002/Accepted: 17 January 2002     

The JUSTSAP experiment on STS-95

An instrumented flow cell in the form of a cylinder with differentially heated end walls and adiabatic sidewalls was flown on STS-95 as the Japan-US Thermal Science Accelerometer Project (JUSTSAP). The purpose of the experiment was to map disturbances in the thermal field during the course of a Shuttle mission in order to correlated them with various mission events and to determine if any global transport could be detected from second order, non-zero time average flows resulting from periodic accelerations (g-jitter). Significant disturbances in the thermal field were noted each time the Shuttle changed attitude, such as the maneuver to -Z solar inertial, which is done periodically for thermal conditioning. Burns from the main thrusters associated with the launch and retrieval of the Spartan satellite produced overturning flows, as might be expected. During extended periods in which the attitude was held constant, the perturbations to the thermal field correlate extremely well with calculated accelerations from gravity gradient and drag. Fair agreement was found between the observed temperature perturbations and those predicted from a modification of the analytical model developed by Bejan and Tien (B&T) for the flow and heat transfer in an infinite cylinder with a constant axial thermal gradient. A full three-dimensional computational fluid dynamic analysis with more realistic thermal boundary conditions provided better agreement after adjustments were made to account for the heat flow away from the measuring thermistors. Once calibrated with a reliable thermal model, the flow cell was found to serve as a high-precision accelerometer, capable of measuring the quasi-steady acceleration with a sensitivity of better than 0.1 micro-g in the presence of the higher amplitude g-jitter typical of Shuttle operations. Further, it was found that the gravity gradient acceleration accounted for virtually all of the observed quasi-steady accelerations during such extended periods. The thermal response time of the JUSTSAP was too slow to expect to see the effects of fluctuating first order flows resulting from the vibrational environment of the Shuttle. However, an indication of a change in the thermal field near the ends of the flow cell was seen during periods of crew exercise that may possibly be attributed to circulating eddies resulting from the higher order terms in the momentum equation. At higher amplitudes, these second order effects can produce non-zero time average flows of a global nature, as can the start-up transients in first-order periodic flows. No such effects were observed, thus it is possible to place an upper limit on the integrated power spectral density of the vibrational environment experienced as well as the nature of the start-up transients of the periodic flows.     

Effect of inner diameter on friction torque in the friction welding of pipes

To clarify the joining mechanism of friction welding, the authors have previously investigated joining phenomena in the first phase of friction welding using solid round bars.^1-5 The results obtained in these studies have led to the proposal of a method for simulation of friction torque in the first phase of friction welding with the friction welding conditions and the physical values of the base metals adopted as key parameters of interest. Results have also led to the development of a method for simple estimation of the initial torque based on the base metal yield strength at the seizure temperature of the faying surfaces.⁶