Dielectric properties of iron doped calcium copper titanate,CaCu<Subscript>3</Subscript>Ti<Subscript>3.9</Subscript>Fe<Subscript>0.1</Subscript>O<Subscript>12</Subscript> ceramic

Dielectric properties of iron doped CaCu₃Ti₄O₁₂ (CCTO), viz. CaCu₃Ti_3.9Fe_0.1O₁₂ (CCTFO) prepared by a novel semi-wet route have been investigated. X-ray diffraction of powder sintered at 900 °C show formation of single phase solid solution. Energy dispersive X-ray spectroscopy (EDX) confirmed the presence of CuO rich phase at grain boundaries of CCTFO. Nature of dielectric relaxation observed above room temperature is studied using complex plane impedance analysis and modulus spectroscopy. It has been found that out of the two relaxations reported earlier above room temperature, one occurring at lower temperature is due to grainboundaries interfacial polarization.     

Adaptive Congestion Controller for ABR Traffic in ATM Network

One of the imperatives for improving the quality-of-service (QoS) of high-speed networks of next generation is to reduce congestion. Congestion occurs when the resource demand exceeds the capacity of the network. The purpose of this paper is to analyze the performance of Robust Adaptive Congestion Control algorithm for available bit rate traffic in asynchronous transfer mode networks and suggest improvements of the algorithm for better performance and fairness. The results of simulation presented here corroborates the fact that the improved algorithm reduces settling time and cell loss ratio and thus maximizes utilization of the network.     

Atomic layer deposition of HfO2 thin films and nanolayered HfO2–Al2O3–Nb2O5 dielectrics

Smooth, 4–6-nm thick hafnium oxide films were grown by atomic layer deposition from HfI₄ or HfCl₄ and H₂O on SiO₂/Si(1 0 0) substrates at 300 °C. Non-uniform films were obtained on hydrogen-terminated Si(1 0 0). The stoichiometry of the films corresponded to that of HfO₂. The films contained small amounts of residual chlorine and iodine. The films deposited on SiO₂/Si(1 0 0) were amorphous, but crystallized upon annealing at 1000 °C. In order to decrease the conductivity, the HfO₂ films were mixed with Al₂O₃, and to increase the capacitance, the films were mixed with Nb₂O₅. The capacitance–voltage curves of the Hf–Al–O mixture films showed hysteresis. The capacitance–voltage curves of HfO₂ films and mixtures of Hf–Al–Nb–O were hysteresis free.     

Response of an Unconfined Aquifer Induced by Time Varying Recharge from a Rectangular Basin

An analytical solution is developed to predict spatio-temporal variation of the water table in a 2-D aquifer system which is receiving transient recharge from an overlying basin of rectangular shape. The transient recharge function is approximated by a number of line segments. Application of the solution is demonstrated with the help of an example problem.     

Two-Dimensional Modelling of Water Table Fluctuations due to Time-Varying Recharge from Rectangular Basin

A prior knowledge of the water table fluctuations, in response to the proposed recharge scheme, is essential to achieve the preset objectives of ground water resources management. In this paper an analytical solution of the linearised Boussinesq's equation is presented to predict the spatio-temporal variation of the water table in an aquifer system in response to time-varying recharge applied through a rectangular basin. The recharge function is approximated by introducing a number of line segments depending on its nature of variation. The solution is obtained by using finite Fourier sine transform and its application is demonstrated for a case of periodically applied recharge.     

Hazard rate estimation from incomplete and unclean warranty data

Warranty data are a rich source of information for feedback on product reliability. However, two-dimensional automobile warranties that include both time and mileage limits, pose two interesting and challenging problems in reliability studies. First, warranty data are restricted only to the reported failures within warranty coverage and such incompleteness can lead to inaccurate estimates of field failure rate or hazard rate. Second, factors such as inexact time/mileage data and vague reported failures in a warranty claim make warranty data unclean that can suppress inherent failure pattern. In this paper we discuss two parameter estimation methods that address the incompleteness issue. We use a simulation-based experiment to study these estimation methods when departure from normality and varying amount of truncation exists. Using a life cycle model of the vehicle, we also highlight and explore issues that lead to warranty data not being very clean. We then propose a five-step methodology to arrive at meaningful component level empirical hazard plots from incomplete and unclean warranty data.     

Impedance of a goat eye lens

Cyclins are essential proteins in cell cycle control, and their deranged expression has been reported to be associated with malignant transformation. Involvement of cyclins in the development of endometrioid carcinomas of the endometrium was studied immunohistochemically using antibodies against both cyclin A and tumor suppressor gene product p53, and their expression was compared with that of Ki-67 antigen. Sixty-two cases of endometrial endometrioid carcinoma and 20 cases of normal endometrium (10 proliferative and 10 secretory phase) were examined. Of the 62 endometrioid carcinomas, atrophic endometrium and hyperplasia were found adjacent to the cancers in 30 and 19 cases respectively. Cyclin A was expressed in < 1% of the glandular cells of normal endometrium in the proliferative phase and in hyperplasia, but was negligible in normal secretory phase and atrophic endometrium. p53 was almost always negative in normal endometrium and hyperplasia. Of the 62 endometrioid carcinomas, 12 tumors (19.4%) overexpressed cyclin A and 21 tumors (33.8%) overexpressed p53 (positive cells > 1%). Cyclin A and p53 were more frequently expressed in poorly differentiated tumors than in well differentiated tumors (cyclin A, p = 0.002; p53, p = 0.016). In addition, cyclin A-positive cells were topographically related to those cells positive for p53 as well as Ki-67. In conclusion, the abnormal expression of cyclin A and p53 is associated with high-grade endometrial endometrioid carcinomas.     

Severe hypercalcemia caused by Milk‐Alkali syndrome requiring urgent hemodialysis – Tums by the ton

An increased frequency of the Milk‐Alkali syndrome in the last several years has been noticed related to increasing use of calcium carbonate as a phosphate binder in CKD patients, as an antacid or as calcium supplementation. We present a case of severe hypercalcemia secondary to Milk‐Alkali syndrome that precipitated acute renal failure requiring urgent hemodialysis. A 59-year‐old male with history of hypertension, diabetes mellitus, and acid reflux presented to the ER with confusion, lethargy, nausea, vomiting, and diarrhea. His family relayed a history of recent indigestion and relief with Tums. He was taking several tablets at short intervals to self‐treat the indigestion. At the time of presentation, patient was confused and noted to be dehydrated. Lab findings were significant for elevated BUN/Cr‐ 121 mg/dl/11.1 mg/dl (baseline Cr 1.1 mg/dl few months ago), bicarbonate 38 mg/dl, calcium 16.7 mg/dl, ionized Ca of 1.76 mmol/L, iPTH 10 pg/ml, PTHrP 0.7 pg/ml. Medical management with intravenous fluids and furosemide showed no improvement in renal failure, or calcium level. Patient was then started on hemodialysis with 2.0 mmol/L calcium in the dialysate the next day. There was gradual improvement in patient's mental status, calcium values, and renal failure over the ensuing 2 weeks.
Discussion and Conclusions:  The diagnosis of Milk‐Alkali syndrome is made on the basis of history. Metabolic abnormalities involved in this syndrome are hypercalcemia with low to normal PTH and Vit. D levels, renal failure, and metabolic alkalosis. Failed medical management required acute dialysis in this patient. Acute hemodialysis in such a case could be life saving. Due to increasing use of calcium carbonate for dyspepsia and osteoporosis, patients should be made aware of these severe, potentially life-threatening adverse effects.