Entsalzung von Umkehrosmosekonzentraten mittels elektrisch getriebenen Membranverfahren zur Maximierung der Permeatausbeute einer Prozesswasseraufbereitungsanlage

Worldwide present water stress situations lead to the necessity to use alternative water sources like brackish water or wastewater. To enable this, new desalination technologies like electrically driven membrane processes have to be implemented. These technologies were used to desalinate the reverse osmosis concentrate of a process water treatment plant up to a certain point, at which the resulting diluate could be used as feed water for the reverse osmosis. As a result, the concentrate volume to be discharged was halved and the permeate yield of the overall plant was increased. A focus was set on the required energy consumption for the additional treatment step.     

Limit analysis of plates using the EFG method and second‐order cone programming

The meshless element‐free Galerkin (EFG) method is extended to allow computation of the limit load of plates. A kinematic formulation that involves approximating the displacement field using the moving least‐squares technique is developed. Only one displacement variable is required for each EFG node, ensuring that the total number of variables in the resulting optimization problem is kept to a minimum, with far fewer variables being required compared with finite element formulations using compatible elements. A stabilized conforming nodal integration scheme is extended to plastic plate bending problems. The evaluation of integrals at nodal points using curvature smoothing stabilization both keeps the size of the optimization problem small and also results in stable and accurate solutions. Difficulties imposing essential boundary conditions are overcome by enforcing displacements at the nodes directly. The formulation can be expressed as the problem of minimizing a sum of Euclidean norms subject to a set of equality constraints. This non‐smooth minimization problem can be transformed into a form suitable for solution using second‐order cone programming. The procedure is applied to several benchmark beam and plate problems and is found in practice to generate good upper‐bound solutions for benchmark problems. Copyright © 2009 John Wiley & Sons, Ltd.     

Selecting at-risk first-grade readers for early intervention: Eliminating false positives and exploring the promise of a two-stage gated screening process.

The purposes of this study were (a) to identify measures that when added to a base 1st-grade screening battery help eliminate false positives and (b) to investigate gains in efficiency associated with a 2-stage gated screening procedure. We tested 355 children in the fall of 1st grade and assessed for reading difficulty at the end of 2nd grade. The base screening model included measures of phonemic awareness, rapid naming skill, oral vocabulary, and initial word identification fluency (WIF). Short-term WIF progress monitoring (intercept and slope), dynamic assessment, running records, and oral reading fluency were each considered as an additional screening measure in contrasting models. Results indicated that the addition of WIF progress monitoring and dynamic assessment, but not running records or oral reading fluency, significantly decreased false positives. The 2-stage gated screening process using phonemic decoding efficiency in the 1st stage significantly reduced the number of children requiring the full screening battery. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A method for performing fully quantum mechanical simulations of gated silicon quantum wire structures

As transistors get smaller, fully quantum mechanical treatments are required to properly simulate them. Most quantum approaches treat the transport as ballistic, ignoring the scattering that is known to occur in such devices. Here, we review the method we have developed for performing fully quantum mechanical simulations of nanowire transistor devices which incorporates scattering through a real-space self-energy, starting with the assumption that the interactions are weak. The method we have developed is applied to investigate the ballistic to diffusive crossover in a silicon nanowire transistor device.     

Cold atmospheric plasma disinfection of cut fruit surfaces contaminated with migrating microorganisms

The efficacy of cold atmospheric gas plasmas against Escherichia coli type 1, Saccharomyces cerevisiae, Gluconobacter liquefaciens, and Listeria monocytogenes Scott A was examined on inoculated membrane filters and inoculated fruit surfaces. Inoculated samples were exposed to a cold atmospheric plasma plume generated by an AC voltage of 8 kV at 30 kHz. The cold atmospheric plasma used in this study was very efficient in reducing the microbial load on the surfaces of filter membranes. However, its efficacy was markedly reduced for microorganisms on the cut surfaces. This lack of effect was not the result of quenching of reactive plasma species responsible for microbial inactivation but principally the result of the migration of microorganisms from the exterior of the fruit tissue to its interior. The velocity of migration through melon tissues was estimated to be around 300 microm min(-1) for E. coli and S. cerevisiae and through mango tissues to be 75 to 150 microm min(-1). These data can serve as operational targets for optimizing the performance of gas plasma inactivation processes. The current capabilities of cold atmospheric plasmas are reviewed and ways to improve their bactericidal efficacy are identified and discussed. Considerable scope exists to enhance significantly the efficacy of cold atmospheric plasmas for decontaminating fresh cut fruits.     

The effects of aging on memory for sequentially presented objects in rats.

The current study investigated memory for sequentially presented objects in young rats 6 months old (n = 12) and aged rats 24 months old (n = 12). Rats were tested on a task involving three exploratory trials and one probe test. During the exploratory trials, the rat explored a set of three sequentially presented object pairs (A-A, B-B, and C-C) for 5 min per pair with a 3-min delay between each pair. Following the exploratory trials, a probe test was conducted where the rat was presented simultaneously with one object from the first exploratory trial (A) and one object from the third exploratory trial (C). Results from the exploratory trials showed no significant age-related differences in exploration, indicating that 24-month-old rats explored the object pairs as much as 6-month-old rats. The probe test demonstrated that 6-month-old rats spent significantly more time exploring object A compared to object C, indicating that young rats show intact temporal order memory for the exploratory trial objects. However, 24-month-old rats showed no preference for object A and spent a relatively equal amount of time exploring objects A and C. The results suggest that temporal order memory declines as a result of age-related changes in the rodent brain. The findings also may reflect differences in attraction to objects with different memory strengths. Since age-related differences were not detected during the exploratory trials, age-related differences on the probe trial were not due solely to decreased exploration, motivation, or locomotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Model of FRP-Confined Concrete Cylinders in Axial Compression

This paper introduces a dilatancy-based analytical model of the response of an axially loaded concrete cylinder, confined with a fiber-reinforced polymer (FRP) composite jacket. Model construction is based on the experimentally based observation that the relation between axial secant stiffness and the lateral (dilatancy) strain is effectively unique for cylinders with the same unconfined concrete strength, although the confinement levels may differ. Model development incorporates strength degradation of the concrete with dilatancy (lateral dilation); this feature allows one to demonstrate that the performance of FRP-confined concrete is consistent with the strength envelope obtained from triaxial tests. Model validation is accomplished by comparisons with existing test database and the new results on large-scale concrete cylinders. The results of the validation reveal good agreement with key response functions and parameters. The present study illustrates basic constitutive equations to model FRP-confined concrete in a more rational manner.     

Scaling analysis of conservative cascades, with applications tonetwork traffic

Previous studies have demonstrated that measured wide-area network traffic such as Internet traffic exhibits locally complex irregularities, consistent with multifractal behavior. It has also been shown that the observed multifractal structure becomes most apparent when analyzing measured network traffic at a particular layer in the well-defined protocol hierarchy that characterizes modern data networks, namely the transport or transmission control protocol (TCP) layer. To investigate this new scaling phenomenon associated with the dynamics of measured network traffic over small time scales, we consider a class of multiplicative processes, the so-called conservative cascades, that serves as a cascade paradigm for and is motivated by the networking application. We present a wavelet-based time/scale analysis of these cascades to determine rigorously their global and local-scaling behavior. In particular, we prove that for the class of multifractals generated by these conservative cascades the multifractal formalism applies and is valid, and we illustrate some of the wavelet-based techniques for inferring multifractal scaling behavior by applying them to a set of wide-area traffic traces     

An outcrossed canine pedigree for linkage analysis of hip dysplasia

Twenty-four hip replacements were performed with use of a medial protrusio technique to stabilize the fit of a hemispherical metal shell in the acetabulum in nineteen patients who had dysplasia of the hip. All of the hips were followed for a minimum of five years (average, seven years; range, five to thirteen years). Six of the hips were type I, seven were type II, eight were type III, and three were type IV according to the criteria of Crowe et al. The acetabular cup was implanted with the medial aspect of its dome beyond the Kohler line (drawn from the ischium along the ilioischial line) in all hips. An autogenous graft sculpted from the femoral head was used to cover 15 to 30 percent of the superolateral portion of the cup in one type-I hip, four type-III hips, and one type-IV hip. The need for these six bone grafts could have been avoided by reaming two to three millimeters more medially or by allowing 20 percent of the superolateral portion of the cup to be uncovered. Sixty to 84 percent of each bone graft was resorbed, effectively leaving the superolateral portion of the cup uncovered. The amount of the surface of the cup that was beyond the Kohler line averaged 41 percent for the six type-I hips, 43 percent for the seven type-II hips, 41 percent for six of the type-III hips, and 44 percent for one of the type-IV hips. Crossing of the ilioischial and iliopubic lines was noted on the radiographs of two type-III and two type-IV hips. Radiographs of two type-I hips and one type-II hip showed 7 to 17 percent of the surface of the dome of the cup through the internal pelvic wall (beyond the iliopubic line). None of the twenty-four metal shells were revised. A reoperation was performed on two hips to exchange a worn polyethylene insert, and three femoral components that had been fixed without cement were revised because of mechanical loosening. Wear averaged 0.26 millimeter per year in the fourteen hips that had a titanium femoral head and 0.09 millimeter per year in the nine hips that had a cobalt-chromium femoral head. The remaining hip had a ceramic femoral head, and the wear rate was 0.09 millimeter per year. The medial protrusio technique is a predictable, reproducible method for obtaining fixation of a porous-coated, hemispherical acetabular component in a dysplastic acetabulum. The technique permits the use of a porous-coated (bone-ingrowth) component; avoids the use of support bone graft and thereby reduces the operative time; facilitates rehabilitation by permitting earlier weight-bearing of the hip; and permits the use of a modular bearing surface, which may allow future exchange of only this surface rather than revision of the entire acetabular component because of excessive wear.