De-t-butylation of t-butylphenols over dealuminated zeolites in liquid-solid system

Liquid-solid phase de-t-butylation of p-t-butylphenols was carried out over original and dealuminated zeolites to determine the effect of catalyst pore size and acidity on the reaction rate and catalyst fouling rate. The de-t-butylation rate over the original zeolites was mainly dependent upon their micro pore sizes. Although the dealumination by acid leaching decreased strong acid sites, the de-t-butylation rate over dealuminated HY zeolite was higher than that on the original zeolite. The present dealumination is a useful method to prepare an acid catalyst for de-t-butylation in a liquid-solid system.     

Study of defect levels in CdTe using thermoelectric effect spectroscopy

We have studied the defect levels in as grown and post growth processed cadmium telluride (CdTe) using thermoelectric effect spectroscopy (TEES) and thermally stimulated current (TSC) techniques. We have extracted the thermal energy (E_th) and trapping cross section (σ_th) for the defect levels using the initial rise and variable heating rate methods. We have identified 10 different defect levels in the crystals. Thermal ionization energy values obtained experimentally were compared to theoretical values of the transition-energy levels of intrinsic and extrinsic defects and defect complexes in CdTe determined by first-principles band-structure calculations. On the basis of this comparison, we have associated the observed ionization levels with various native defects and impurity complexes.     

Comparison of Gelation Mechanism of Surimi between Heat and Pressure Treatment by Using Rheological and NMR Relaxation Measurements

ABSTRACT: The stress-relaxation and nuclear magnetic resonance (NMR) proton spin-spin relaxation time (¹H T₂) measurements were performed to elucidate the gelation mechanism of heated and pressurized surimi gels. Numerical inverse Laplace transformation of the stress-relaxation data showedlarge distributions of stress-relaxation times and the Kohlrauch-Williams-Watts (KWW) equation described well the stress-relaxation process for each gel. NMR measurement gave information about the content of the exposed protein surface. From these results it is considered that the heat treatment induces the denaturation and re-aggregation of protein, which contribute to the formation of strong network structure. On the other hand, the pressure treatment contributes to the formation of weak cross-links made by the aggregation of protein in native form.     

Radiation measurements in large-scale kerosene pool flames using high-speed thermography

Details of apparent temperature distributions in large-scale kerosene pool flames in a 2.7 m square tank were measured by high-speed thermography which stores a thermal image in the form of a thermal TV color image with 25,600 data points every 0.1 second. The apparent temperature image can be changed to irradiance by simple approximations. The irradiance of the data (4 cases and 280 images) was compared with that of a wide-angle thermopile radiometer to verify the data from the thermography. A series of data recorded at intervals of one and five seconds was also analyzed to obtain the radiance distribution in the flame. The analysis allows the following conclusions: Irradiance values obtained by high-speed thermography are not very different from those of a conventional wide-angle thermopile radiometer. The high radiance zone, which ordinary cameras do not show, was determined by the average value of each of 70 apparent temperature images, and the center of the high radiance zone is located at about 0.3 D (D is the tank diameter). The moderately high apparent temperature range of 1232K–1448K apparently has a strong influence on the irradiance of pool flames.     

Dyeing Properties of Monoazo Dyes Derived from Aminonophthothiazole Derivatives

The preparation and dyeing properties of new monoazo dyes prepared from aminonophthothiazole derivatives using a tertiary amine as the coupling component. The fibres considered are: polyester, cellulose acetate, nylon 6 and acrylic.     

Empirical modeling of systematic spectrophotometric errors

Spectrophotometers, as electro-mechanical-optical devices, perform at a finite level of accuracy. This accuracy is limited by such factors as monochromator design, detector linearity, and cost. Generally, both the diagnosis and correction of spectrophotometric errors require a number of calibrated standard reference materials and considerable effort and commitment on the part of the user. A technique using multiple linear regression has been developed, based on the measurement of several suitably chosen standard reference materials, to both diagnose and correct systematic spectrophotometric errors, including photometric zero errors photometric linear and nonlinear scale errors, wavelength linear and nonlinear scale errors, and bandwidth errors. The use of a single chromatic ceramic tile to correct systematic errors improved the colorimetric accuracy of a set of chromatic and neutral tiles by a factor of two for a typical industrial-oriented spectrophotometer. Greater improvement can be achieved by increasing the number of tiles and performing a separate regression at each measured wavelength., These techniques have been extremely useful in improving inter-instrument agreement for instruments with similar geometry.     

Comparison of amyloid deposition in two lines of transgenic mouse that model familial amyloidotic polyneuropathy, type I

Aortic disease frequently requires extended and multiple resections. Occasionally, resection of the entire aorta may be indicated. At our Institution, from 1982 to 1994, 34 patients were operated upon for extended and total simultaneous aortic replacement. In seven patients, the aorta was replaced from valve to bifurcation; in 27, the aortic valve was included. Operations were performed with circulatory arrest under profound hypothermia. As the first step, the aortic valve and ascending aorta are replaced and the coronary arteries are reconnected, following which the aortic arch is reconstructed. Meanwhile, a second surgical team proceeds to open the thoracoabdominal aorta and tie up the intercostal orifices. If circulatory arrest is likely to exceed 60 minutes, the aortic graft is clamped and upper body perfusion (1000 cc/min) is begun. Finally, the thoracoabdominal aorta is fully replaced. Cardiopulmonary bypass (CPB) with rewarming is resumed only after the operation has been completed. Thirty-four patients survived operation; five died within 1 month for an overall mortality of 14.7%. No mortality occurred in the most recent nine operations. No permanent spinal neurological deficits occurred. Total simultaneous aortic replacement for treatment of extended aortic disease may be reasonable using our approach.     

High-sensitivity Hi-Lo germanium avalanche photodiode for 1.5 ?m-wavelength optical communication

A high-sensitivity small-detectable-area Hi-Lo germanium avalanche photodiode (Ge APD) was developed for use in 1.55 ?m wavelength optical communication systems. This device has Hi-Lo (p+nn?) impurity profile. Its detectable area is 30 ?m in diameter for single-mode optical-fibre use. The minimum average received signal level obtained was ?40.5 dBm (at 450 Mbit/s, ? = 1.55 ?m, BER = 10?9, return-to-zero). This is 0.7 dB better than the value for the 80?m diameter similar structure Ge APD.     

Hydroliquefaction of Australian coals with recycled slurry oil in a 1 kg h−1 continuous reactor

Coals from major Australian fields considered as suitable hydroliquefaction feedstocks were hydrogenated in a 1 kg h^?1 continuous reactor unit at reaction conditions 415–435 °C and 21 MPa using a stirred flow reactor with retention time of about 2 h. The effect of coal rank and the catalytic effects of disposable iron-based (red mud plus sulphur) catalysts were studied. The system was operated continuously with process-derived recycle solvent for up to 236 h. The time for a single pass of recycle solvent was estimated to be 20 h. Distillate oil yields in the range 35–53% on daf coal were obtained under catalytic operation. The heavier product oils were shown to contain predominantly aromatics, hydroaromatics and phenolics. This indicates that fairly severe hydro-treatment would be required to produce specification diesel and aviation turbine fuels. Recycle solvent composition was observed to stabilize in 2–4 passes after making a process change. These data compare favourably with those obtained on the same coals in larger pilot plants showing that this unit is capable of producing useful yield data.