Piezoelectric hydrophones from Optimal Design,II: properties

Three-dimensional piezoelectric PZT-air artificial materials, designed using the Optimal Design by the Homogenization Method, with predicted hydrostatic piezoelectric coefficient of 427 pC/N and a hydrophone figure of merit of 29 pm²/N were realized and measured. The measured hydrostatic piezoelectric coefficient was 329 pC/N and a hydrophone figure of merit was19 pm²/N. The differences between predicted and observed properties were ascribed to insufficient polarization, due to the field distribution during poling.     

Piezoelectric hydrophones from optimal designs,Part I: fabrication

Complex three-dimensional optimal designs for improved piezoelectric hydrophones were being realized in lead zirconate titanate piezoelectric ceramics using an indirect solid freeform fabrication technique employing lost molds to define internal void spaces. Lost molds were fabricated by wax-based ink jet deposition, and replicated in PZT ceramic using acrylate suspension polymerization. The physical size of the object is determined by the finest feature present in the design, and by the resolution of the ink jet device. Arrays with 125 repeat units were fabricated with a fidelity of 0.9% in placement of features. The Indirect Solid Freeform Fabrication technique is described in detail.     

Semiconductor drift chambers for position and energy measurements

Semiconductor drift chambers have been recently suggested and feasibility tests performed. This paper presents the first operative silicon drift detectors for position and energy measurements. Design criteria and experimental results in the laboratory and on an accelerator beam are reported.     

Formation of interpolymer complexes between poly(monoethyl itaconate) and poly(N-vinyl-2-pyrrolidone)

This paper reports on the interpolymer complex formation and polymer blends between poly(monoethyl itaconate) (PMEI) and poly(N-vinyl-2-pyrrolidone) (PVP). The formation of the interpolymer complex was found to depend upon the solvent medium. Stoichiometry of the complexes prepared from methanol solutions, as calculated from elemental analysis, is close to 1 : 1. Specific interactions of PMEI/PVP complexes and blends of these polymers have been characterized by FTIR. Strong hydrogen bonding for complexes and blends has been found. A calorimetric study of the complexes and blends has been performed over a wide temperature range.     

Dose-ranging study of tolterodine in patients with detrusor hyperreflexia

Tolterodine is a potent antimuscarinic agent specifically developed for the treatment of urinary urge incontinence and other symptoms related to the overactive bladder. In order to assess the optimum dosage for use in future clinical studies, a double-blind, randomized, placebo-controlled, parallel-group, multicenter study was performed in 90 patients with detrusor hyperreflexia and symptoms of urinary urgency, frequency, and/or urge incontinence. Urodynamic variables, micturition diary variables, and subjective urinary symptoms were measured before and after 2 weeks' treatment with either placebo or tolterodine 0.5, 1, 2, or 4 mg twice daily (bd). Serum drug concentrations, electrocardiogram recordings, blood pressure, and incidence of adverse events were also assessed. Linear regression analysis showed a significant dose-response relationship for several clinically relevant urodynamic variables, while there was a trend towards an improvement in micturition diary variables and subjective assessment of symptoms with increasing dosages of tolterodine. There were no safety or tolerability concerns regarding any of the dosages of tolterodine investigated, although 2 patients treated with a dosage of 4 mg bd experienced urinary retention that necessitated dosage reduction. The results of this study suggest that tolterodine is well-tolerated and exerts a dose-dependent effect on bladder function in patients with detrusor hyperreflexia. The optimum dosage of tolterodine for use in future studies is 1-2 mg bd.     

Thirteen cystic fibrosis patients, 12 compound heterozygous and one homozygous for the missense mutation G85E: a pancreatic sufficiency/insufficiency mutation with variable clinical presentation

To study the severity of mutation G85E, located in the first membrane spanning domain of the CFTR gene, we studied the clinical features of 13 Spanish patients with cystic fibrosis (CF) carrying this mutation. G85E accounts for about 1% of Spanish CF alleles. One patient was homozygous G85E/G85E and the rest were compound heterozygotes for G85E and other mutations (delta F508 nine patients, delta I507 two patients, and 712-1G > T one patient). The characteristics of the pooled G85E/any mutation group were compared with those of 30 delta F508 homozygotes. Mean age at diagnosis and percentage of ideal height for age were higher in the G85E/any mutation group (4.2 (SD 4.7) v 2.4 (SD 2.3), p < 0.05, and 102.8 (SD 4.7) v 97.8 (SD 4.1), p < 0.01), both probably related to the greater prevalence of pancreatic sufficiency (70% v 0%, p < 0.01). The G85E homozygote was pancreatic sufficient. Sweat sodium levels were slightly higher, and salt loss related problems more frequent, in the G85E/any group. Two of the G85E patients died of respiratory failure aged 6 and 14 years. Striking discordance in the phenotype was observed in two pairs of sibs, one of them dizygotic twins, suggesting that factors, genetic and environmental, other than CFTR genotype are important in determining CF phenotype.     

A Bayes nonparametric framework for software-reliability analysis

This paper presents a Bayes nonparametric approach for tracking and predicting software reliability. We use the common assumptions on the software operational environment to get a stochastic model where the successive times between software failures are exponentially distributed; their failure rates have Markov priors. Under these general assumptions we give Bayes estimates of the parameters that assess and predict the software reliability. We give algorithms (based on Monte-Carlo methods) to compute these Bayes estimates. Our approach allows the reliability analyst to construct a personal software reliability model simply by specifying the available prior knowledge; afterwards the results in this paper can be used to get Bayes estimates of the useful reliability parameters. Examples of possible prior physical knowledge concerning the software testing and correction environments are given. The maximum-entropy principle is used to translate this knowledge to prior distributions on the failure-rate process. Our approach is used to study some simulated and real failure data sets     

Improvements in the decay heat model in the thermalhydraulic code TRAC-BF1

The implemented models in TRAC-BF1 for the decay heat calculations are based on the 1971 American Nuclear Society (ANS) Standard or the 1979 ANS Standard if selected by the user. With the entry into force of the 1994 ANS Standard and the subsequent review, the TRAC-BF1 models were made completely obsolete, so a revision of the older models and the implementation of ANSI/ANS-5.1-2005 Standard in the code are required. In this paper, a novel numerical study is presented based on the analytical resolution of the decay heat equation which takes into account the number of reactor operation histories, the number of fissionable nuclides, and the number of groups per fissile. Moreover, this paper describes the influence of the short-term power histories on the total decay heat power calculation due to the high interest in the simulation of severe transients, such as Anticipated Transients without SCRAM, which cannot be ignored in nuclear safety analysis.     

Green framework for future heterogeneous wireless networks

Energy-efficient communication has sparked tremendous interest in recent years as one of the main design goals of future wireless Heterogeneous Networks (HetNets). This has resulted in paradigm shift of current operation from data oriented to energy-efficient oriented networks. In this paper, we propose a framework for green communications in wireless HetNets. This framework is cognitive in holistic sense and aims at improving energy efficiency of the whole system, not just one isolated part of the network. In particular, we propose a cyclic approach, named as energy-cognitive cycle, which extends the classic cognitive cycle and enables dynamic selection of different available strategies for reducing the energy consumption in the network while satisfying the quality of service constraints.