High Temperature Property Development of Bauxite Based Bricks

Physical properties and microstructural evolution on firing of 3 types of bauxite based refractory bricks were carried out using techniques such as porosimetry,XRD and SEM.The groups differed from each other by progressive refining of the matrix or bond phase.It is revealed that such a refinement of the matrix can improve the high temperature properties of the bricks made from poor grade materials.     

On energy arguments applied to the hydrodynamic impact force

The hydrodynamic impact problem is investigated within the framework of potential-flow theory. The vertical load acting on the rigid body is derived based on either momentum or energy conservation, and using the concept of added mass together with a homogeneous Dirichlet condition for the potential on the free surface as usually done to model an impact problem. It is demonstrated that the use of this simplified dynamic free-surface condition, instead of the fully nonlinear one, has a direct influence on the computation of the loads. In particular, the equivalence of momentum and energy analysis is in general not recovered. The situation is then highlighted by performing an asymptotic analysis of the two-dimensional blunt-body asymmetric impact problem. The asymptotic solution is given explicitly and validated through comparisons with experimental results. The energy distribution is then studied. It is shown that the contradiction between momentum and energy analysis can be removed, provided that the flux of energy through the jets is taken into account in the energy balance. If the simplified free-surface condition is indeed valid in the far-field, nonlinear terms must be retained near the body, in the spray-root domains. To leading order, the energy distribution during the gravity-free inertia stage does not depend on the blunt-body shape. The general analysis based on momentum or energy conservation suggests that this result also applies for arbitrary body shape as soon as a homogeneous Dirichlet condition can be applied as a dynamical free-surface boundary condition. In this case, and for a constant vertical impact velocity, half the work performed by the body would seem to be transferred to the fluid as kinetic energy within the spray.     

Comparative efficacy of calcipotriol (MC903) cream and betamethasone 17-valerate cream in the treatment of chronic plaque psoriasis. A randomized, double-blind, parallel group multicentre study. Calcipotriol Study Group

PURPOSE: Ultrasound estimated bladder weight was compared before and after surgery for benign prostatic hyperplasia (BPH) to reveal a possible reversible change in bladder hypertrophy. MATERIALS AND METHODS: Ultrasound estimated bladder weight was measured before and after subcapsular (17) or transurethral (16) prostatectomy in 33 male patients with BPH. Sequential changes in the American Urological Association symptom score and urinary flow rate were also examined. RESULTS: Along with a significant improvement in the American Urological Association symptom scores and maximum flow rate, ultrasound estimated bladder weight decreased from 52.9 +/- 22.6 to 31.6 +/- 15.8 gm. in 12 weeks after treatment. In all but 4 patients (29 of 33, or 87.9%) ultrasound estimated bladder weight decreased to less than 35.0 gm. in 12 weeks after treatment. Interestingly, in all patients with an initial ultrasound estimated bladder weight of greater than 80 gm. the bladder weight still remained at an abnormally high level 12 weeks after treatment. CONCLUSIONS: Bladder hypertrophy was completely reversible after the surgical treatment of the obstruction in the majority of patients with BPH. The measurement of ultrasound estimated bladder weight was of value in monitoring therapeutic effects in BPH patients. An extraordinarily high ultrasound estimated bladder weight of 80 gm. or more might suggest degenerative and irreversible pathological changes in the bladder detrusor.     

Classification of the spoilage flora of raw and pasteurized bovine milk, with special reference to Pseudomonas and Bacillus

The purpose of this study was to examine the relationship of job satisfaction to job difficulty and worthiness, reported by the clinical psychologists who worked at medical institutions. A mail survey of 748 clinical psychologists working at hospital and clinics revealed the following results. First, job satisfaction was related more to job situation than job content. Also, job satisfaction was low among those who worked at non-university psychiatric or geriatric hospitals, who did not practice psychotherapy, and who were not in education, research, or management. In addition, compared to the high job satisfaction group, the low group perceived more incongruity between institutional climate and their psychological work, felt being less valued by other professionals, were less able to function fully as a practicing psychologist, and experienced more role ambiguity as a clinical psychologist in a hospital setting.     

用CAD方法实现铸造砂芯设计

根据组合机床中大型铸铁件的特点，首先提出了砂芯分类及设计原则，开发了砂芯设计程序模块，通过人机对话，自动生成砂芯工艺图。     

Fourier-transform evaluation of phase data in spatially phase-biased TV holograms

TV holograms for spatial phase stepping are formed with a small angular offset between the object and the reference beams to give a spatial frequency bias to the pattern recorded by the TV camera. It is common to set the bias so that there is a 90° or 120°phase shift between adjacent pixels and to use the irradiance of three or more adjacent pixels to evaluate the phase of the interference. We report the Fourier-transform evaluation of such recordings to obtain their phase data. We also demonstrate the direct calculation of the phase difference between successive recordings without intermediate calculation of the random phase of each hologram. This technique is proposed as an approach to pulsed TV holography.     

A silicon test chip for the thermomechanical analysis of MEMS packagings

This paper reports on a method for the investigation of mechanical stress on MEMS sensor and actuator structures due to packaging processes. A silicon test chip is developed and manufactured to validate the simulation results. Finite element analysis (FEA) is used to optimize the geometric parameters and to find a stress sensitive sensor geometry. A diaphragm structure is used as mechanical amplifier for bulk induced stresses during the packaging process. Piezo resistive solid state resistors are doped into the surface of the chip to measure the stress in the diaphragms and at the contact pads being most significant locations for analysis. A high precision ohmmeter was used to measure the resistance prior and past the packaging process. The captured data allows for computation of the resulting stress loads in magnitude. Therefore, a stress evaluation of different packaging technologies is conducted and the impact of the packaging process on reliability can be estimated immediately.     

Carbon dioxide evolution of refrigerated meat

The carbon dioxide (CO(2)) evolution from pork loins stored in air or nitrogen at 5°C was measured. The loins were cut immediately after slaughter ('pre-rigor meat.'), or approximately 20 h after slaughter ('post-rigor meat'). CO(2) evolution rate was highest during the first day (2·3 × 10(-3)mlcm(-2)h(-1)) and then declined to approximately 0·5 × 10(-3)mlcm(-2)h(-1). The rate was fairly constant during this later phase, and there were no large differences between aerobically and anaerobically stored meat, or between pre-rigor meat and post-rigor meat. Four hypotheses for the origin of the CO(2) evolution are discussed: (1) diffusion from a pre-formed pool in the meat; (2) aerobic energy metabolism of the meat cells; (3) other biochemical reactions of the meat cells; and (4) microbial activity. None of the hypotheses completely supports the experimental results of the investigation. The impact of these findings on the vacuum packaging of meat is discussed.     

Influence of mesostasis in volcanic rocks on the alkali-aggregate reaction

Mesostasis material present in the interstices of volcanic rocks is the main cause of the alkali-aggregate reaction (AAR) in concretes made with these rock aggregates. Mesostasis often is referred to as volcanic glass, because it has amorphous features when analyzed by optical microscopy. However, this study demonstrates that mesostasis in the interstitials of volcanic rocks most often consists of micro to cryptocrystalline mineral phases of quartz, feldspars, and clays. Mesostasis has been identified as having different characteristics, and, thus, this new characterization calls for a re-evaluation of their influence on the reactivity of the volcanic rocks. The main purpose of this study is to correlate the characteristics of mesostasis with the AAR in mortar bars containing basalts and rhyolites.     

Resonance measurement technique for viscoelastic properties of damping materials of the porous closed cellular PE foam type

Theoretical and experimental studies of longitudinal and lateral vibrations in a 2D cavity filled with foam viscoelastic material were performed; measurement methods of Lame parameters, as well as viscosity parameters with longitudinal and lateral resonance vibrations in cellular polypropylene loaded by a final mass were proposed. Measurements of the visco-elastic properties of samples from the porous closed cellular polyethylene of a PE foam and EVA ultrathene types were made.