Liquid jet pumped by rising gas bubbles

A two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. Bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they rise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature

Combined radiation, convection, and conduction for a system with a partially transmitting wall

The net radiation method is developed for systems having both opaque and partially transparent walls. Heat convection is present at the surfaces and heat conduction through the windows is taken into account. Specific equations are derived for a window between two parallel plates, where one plate is at an elevated temperature typical of what would be encountered in an electric furnace, and the other plate is being cooled. A two-band model is used with cutoff wavelengths typical of glass or quartz. Numerical results are obtained for the window temperature and the heat flow through the window. The effect on these quantities of various plate temperatures and emissivities is shown

An extension of a theorem of Sahab, Khan, and Sessa

A fixed point theorem of Fisher and Sessa is generalized to locally convex spaces and the new result is applied to extend a recent theorem on invariant approximation of Sahab, Khan, and Sessa

Low Incidence of Contrast Induced Nephropathy after Coronary Angiography in Patients with Advanced Chronic Kidney Disease Treated with Prophylactic Continuous Veno-venous Hemofiltration

Introduction: Contrast-induced nephropathy (CIN) is associated with increased risk of in-hospital morbidity and mortality. The purpose of this study was to find out whether continuous venovenous hemofiltration (CVVH) after coronary angiography in chronic kidney disease (CKD) patients is associated with a lower incidence of CIN than that reported in the literature. Methods: All patients with CKD who underwent coronary angiography in the Chest Disease Hospital, Kuwait, between January 2004 and December 2005 were treated by CVVH after the procedure. Renal function was assessed before and after the procedure. Results: A total of 98 patients were enrolled in the study, 52 (53.1%) of whom were males. Their mean age was 60.7 years. Before the procedure, the mean serum creatinine level was 4.65 mg/dl and the mean creatinine clearance (Cr Cl) was 18.04 ml/min. Patients underwent CVVH for a mean duration of 21.3 hours, after a mean time-interval of 44.3 min. Their mean serum creatinine was 4.57 mg/dl at discharge (within the first week after the procedure) and 4.78 mg/dl at 15 days after the procedure. Mean Cr Cl was 18.52 ml/min at discharge and 17.62 ml/min at 15 days after the procedure. There was no statistically significant difference between the mean serum creatinine and Cr Cl values before and after the procedure. However, one patient (1.02%) developed CIN and ended on regular hemodialysis. The in-hospital mortality was 0%. Conclusion: Patients with advanced CKD who undergo coronary angiography may be protected from further deterioration in their renal function after exposure to radiological contrast material if the procedure is immediately followed by CVVH. A randomized controlled clinical trial is needed to verify our encouraging results. Keywords: contrast induced nephropathy, chronic kidney disease, continuous venovenous hemofiltratio

Nd:YAG laser welding of stainless steel 304 for photonics device packaging

Although pulsed Nd:YAG laser welding has been widely used in microelectronics and photonics packaging industry, a full understanding of various phenomena involved is still a matter of trials and speculations. In this research, an ultra compact pulsed Nd:YAG laser with wavelength of 1.064 µm has been used to produce a spot weld on stainless steel 304. The principal objective of this research is to examine the effects of laser welding parameters such as laser beam peak powers, pulse durations, incident angles, focus point positions and number of shots on the weld dimensions: penetration depth and bead width. The ratio of the penetration depth to the bead width is considered as one of the most critical parameters to determine the weld quality. It is found that the penetration depth and bead width increase when the laser beam peak power, pulse duration and number of shot increase. In contrast, the penetration depth decreases when the laser beam defocus position and incident angle increase. This is due to the reduction of the laser beam intensity causing by the widening of the laser spot size. These experimental results provide a reference on an optimal laser welding operations for a reliable photonics device packaging. The results obtained shows that stainless steel 304 is suitable to be used as a base material for photonics device packaging employing Nd:YAG laser welding technique

Tuberculosis diagnosis and treatment practices of private physicians in Karachi, Pakistan

In a densely populated urban area of Karachi, Pakistan, a questionnaire survey was made of the knowledge and practices of 120 private general practitioners about the diagnosis and treatment of tuberculosis (TB). The majority knew that cough, fever and weight loss were the main symptoms of TB, but less than half knew that blood in sputum, poor appetite and chest pain were associated with the disease. Only 58.3% of physicians used sputum microscopy for diagnosing TB and 35.0% used it as a follow-up test. Only 41.7% treated TB patients themselves, the remaining referring their patients to specialists. Around 73.3% of the doctors were aware of the 4 first-line anti-TB drugs. Efforts to improve the knowledge of private practitioners, and strategies to enhance public-private collaboration forTB control in urban areas are urgently required

On the polarization properties of the charmed baryon Lambda^+_c in the Lambda^+_c -> p + K^- + pi^+ + pi^0 decay

The polarization properties of the charmed Lambda^+_c baryon are investigated in weak non-leptonic four-body Lambda^+_c -> p + K^- + pi^+ + pi^0 decay. The probability of this decay and the angular distribution of the probability are calculated in the effective quark model with chiral U(3)XU(3) symmetry incorporating Heavy Quark Effective theory (HQET) and the extended Nambu-Jona-Lasinio model with a linear realization of chiral U(3)XU(3) symmetry. The theoretical value of the probability of the decay Lambda^+_c -> p + K^- + pi^+ + pi^0 relative to the probability of the decay Lambda^+_c -> p + K^- + pi^+ does not contain free parameters and fits well experimental data. The application of the obtained results to the analysis of the polarization of the Lambda^+_c produced in the processes of photo and hadroproduction is discussed.Comment: 10 pages, no figures, Late