Evaluation of passenger train car materials in the cone calorimeter

Recent advances in fire test methods and hazard analysis techniques make it useful to re‐examine passenger train fire safety requirements. The use of test methods based on heat release rate (HRR), incorporated with fire modelling and hazard analysis, could permit the assessment of potential hazards under realistic fire conditions. The results of research directed at the evaluation of passenger train car interior materials in the cone calorimeter are presented. These measurements provide data necessary for fire modelling as well as quantitative data that can be used to evaluate the performance of component materials and assemblies. The cone calorimeter test data were also compared with test data resulting from individual bench‐test methods specified in the FRA fire safety guidelines. The majority of the tested materials which meet the current FRA guidelines show comparable performance in the cone calorimeter. Copyright © 1999 John Wiley & Sons, Ltd.     

Synthesis and adsorption properties of nanocrystalline ferrites for kinetic modeling development

Nanocrystalline ferrites are known to be used in different applications, including industrial wastewater management. For environmental water issues, one of the most widely applied techniques is the adsorption of pollutants. The adsorption capacity of Congo red (CR) dye on different MFe₂O₄ (M = Co²⁺, Mg²⁺, Mn²⁺, Ni²⁺, and Zn²⁺) ferrites, synthesized by coprecipitation method, was determined. Specific isotherms and kinetic models were used to characterize the adsorption process. Interesting results were obtained for MgFe₂O₄ with adsorption capacity ranging from 39% up to 70% dependent on the initial dye concentration. Furthermore, an artificial intelligence model based on neural network was developed in order to model the adsorption rates followed by the generation of 3D adsorption rate models for each type of synthesized ferrite. These models were obtained in order to provide information about the particle-dye system`s kinetics at various initial CR concentration. Specific techniques were used to characterize the functionalized magnetic particles.     

A Scheduling Algorithm with Dynamic Priority Assignment for WCDMA Systems

In third generation WCDMA systems, shared channels allow many users to jointly utilize a single Orthogonal Variable Spreading Factor (OVSF) code. In this paper, we propose a Scheduling Algorithm with Dynamic Priority Assignment (DPA) which is designed for the Downlink-Shared channel (DSCH) of 3G WCDMA systems and operates within a cross layer framework. The DPA scheduler has low computational complexity and is able to provide QoS differentiation among traffic flows based on their delay sensitivity. Through the cross layer framework, DPA takes into account the variations of the wireless channel, and exploits processing gain to improve transmission quality and enable service provisioning when possible. Additionally, by providing a guaranteed rate per traffic flow at each scheduling period, DPA can offer a deterministic delay bound to each connection when transmissions are reliable. Stochastic delay guarantees under transmission power limitations are also provided when the traffic flows are identical. Simulation results show that DPA outperforms Feasible Earliest Due Date (FEDD), a variation of EDD for wireless environments.     

Regeneration of Aged Commercial Three-Way Catalytic Converters

The present work demonstrates for the first time that rejuvenation of the catalytic activity of full-scale aged commercial three-way catalytic (TWC) converters is feasible after treatment with weak oxalic acid solution (0.1 M). Up to 50% reduction in CO, 75% in NO _x and 32% in HC emissions was attained under warm engine driving conditions following regeneration of three aged TWC converters with 42,500, 156,000 and 165,000 km mileage. Efforts to expand the durability of aged commercial TWC converters installed in gasoline-driven cars after applying specific treatments with weak oxalic acid-based solutions appear to be a very promising starting point in recovering to a very large degree their performance.     

High payload dual therapeutic-imaging nanocarriers for triggered tumor delivery

The in vitro and in vivo characterization of an optimized formulation of nanoparticles (NPs) loaded with a high content of dexamethasone palmitate (DEX-P), a chemotherapeutic adjuvant that decreases interstitial fluid pressure in tumors, and (111) In, a signaling agent, is described. These NPs are uniform in size and composition. Single photon emission computed tomography imaging demonstrates significant tumor uptake of (111) In-labeled DEX-P NPs in tumor-bearing mice. As with many nanoparticle-based drug delivery systems, significant liver accumulation is observed. Assessment of liver histology and blood tests show no apparent hepatic or renal toxicity of the DEX-P NPs. Conversion of DEX-P to DEX occurs when DEX-P NPs are incubated with mouse plasma, human tumor homogenate and ascites from tumor bearing mice, but not with human plasma. This conversion is slower in plasma from Es1(e) ((-/-)) /SCID mice, a potential alternative animal model that better mimics humans; however, plasma from these mice are not completely devoid of esterase activity. The difference between blood and tumor esterase activity in humans facilitates the delivery of DEX-P NPs to tumors and the release of dexamethasone by an esterase trigger.     

Life cycle cost assessment of masonry structures

The objective of this study is to propose a life cycle cost (LCC) model able to assess the structural performance of masonry structures. For this purpose the proposed LCC model is used for assessing the structural behaviour of one unreinforced and three retrofitted masonry structures derived following three retrofit scenarios that are suitable for strengthening this type of structures. According to the proposed LCC model the exceedance probabilities required, are calculated by means of fragility analysis (FA). In particular, FA is applied to the unreinforced and retrofitted masonry structures and the limit-states' exceedance frequencies are obtained by convolving fragilities with hazard curve. Life-cycle cost analysis models are recognised as suitable for assessing the structural performance, especially when the structure is expected to be functional for a long period of time. For the needs of the study, linear time history analyses are performed over a large database of natural records.     

A generalized methodology for the gridding of microarray images with rectangular or hexagonal grid

Microarrays provide a simple way to measure the level of hybridization of known probes of interest with one or more samples under different conditions. The rapid development of microarray technology requires the implementation of smart and flexible algorithms to deal either with the great amount of data or with the variations of the used hardware. In this paper, a generalized methodology for spot addressing and gridding of microarray images is presented. The methodology can cope with both rectangular and hexagonal grids, which are used for the probes placement onto the substrate. Initially, the methodology identifies the structure of the image, and an efficient spot-by-spot approach has been developed for the detection of all spots in the image. The evaluation of the methodology was performed using both rectangular and hexagonal structured images, merged in a single dataset. The methodology results in high accuracy in the spots detection, ranging from 92.8 to 99.8 % depending on the dataset used.     

Identification and Adaptive Control for Open Channel Water Flow Systems

Abstract: Despite the continuous advances in the control design for water flow systems such as irrigation and sewer systems, the design and deployment of efficient water flow control systems requires a careful and efficient fine‐tuning of their parameters prior and during the actual system operation. In the majority of water flow control applications, the controller design is based on simplified models (e.g., linear models assuming a fixed time‐delay) for the water flow dynamics and as a result the initial controller design calls for a major fine‐tuning at the initial deployment of the control system; moreover, the frequent changes in water management commands/needs as well as the severe exogenous disturbances call for a continuous update of the controller parameters. Conventional controller tuning approaches cannot be used for the efficient tuning of the controller parameters in water flow control systems, mainly due to the highly nonlinear dependence of the time‐delay with respect to the water flow. In this article, we first introduce and analyze both by means of mathematical analysis and simulation experiments, a computationally simple and efficient methodology for the identification of water flow system dynamics as a State‐dependent Delay Difference Equation (sdDDE) model. The main advantage of this methodology is that it can explicitly identify the nonlinear relationship between the water flow system states and the system time‐delay. Then, we show that such an sdDDE identification scheme can be used for the efficient adaptive tuning of a general class of water flow control systems. More precisely, by exploiting the knowledge—obtained using the sdDDE identification scheme—regarding the nonlinear characteristics of the time‐delay, we come up with a convergent adaptive control scheme, which is able to quickly track rapid changes in setpoint commands and efficiently attenuate severe exogenous disturbances. Simulation results demonstrate that the proposed scheme out‐performs significantly existing well fine‐tuned linear and nonlinear control schemes.     

Bilateral adrenal cortical adenomas in primary hyperaldosteronism

Various 4-alkoxyphenylimidazolidin-2-ones were prepared from benzaldehydes via a Curtius rearrangement and were evaluated for their anticonvulsant activities.     

Mesostructured Silica Supports for Functional Materials and Molecular Machines

Mesostructured silica thin films and particles prepared by surfactant‐templated sol–gel techniques are highly versatile substrates for the formation of functional materials. The ability to deliberately place molecules possessing desired activities in specific spatially separated regions of the nanostructure is an important feature of these materials. Such placement utilizes strategies that exploit the physical and chemical differences between the silica framework and the templated pores. As an example of placement of pairs of molecules, donor and acceptor molecules can be targeted to different regions of mesostructured thin films and energy transfer between them can be measured. The results not only demonstrate the spatial separation but also are used as a molecular ruler to measure the average distance between them. Mesostructured silica is also an excellent support for molecular machines. Molecules that undergo large amplitude motion, when attached to the silica, can function as impellers and nanovalves when activated by light, electrical (redox) and chemical (pH, competitive binding) energy. Derivatized azobenzene molecules, attached to pore walls by using one of the placement strategies, function as impellers that can move other molecules through the pores. Rotaxanes and pseudorotaxanes, placed at pore entrances, function as gatekeepers that can trap and release molecules from the pores when stimulated. Deliberately placed functional molecules on and in mesostructured silica offer many possibilities for both fundamental studies on the nanoscale and for applications in fields as diverse as fluidics, biological drug delivery and controlled release.