High-speed JPEG coder implementation for a smart camera

The compression standard of the Joint Photographic Experts Group (JPEG) for still images is used in many imaging applications. Although machine vision algorithms are based on raw images, massive data reduction of images in many applications is required additionally, e.g. to archive images in the context of automated visual inspection or to store high-speed image sequences when memory space is limited. Especially in embedded systems the software implementation of compression algorithms is too slow to meet real-time requirements. In this paper we present a fast implementation of a JPEG coder in a field programmable gate array (FPGA). This JPEG coder uses the architecture-specific function blocks of a low-cost FPGA (dedicated multipliers, block RAM). Nevertheless, there is hardly any limitation to the generality of the approach, as these building blocks are manufacturer-independent elements of up-to-date FPGA architectures.     

Nonwoven as heat barrier: Modeling of the efficiency of Carbtex fibers

In this work, we examine the use of nonwoven (NW) as heat barrier to protect a metallic substrate. Carbtex fibers consisting in a thermoplastic core inside an oxidized outer shell (polyacrylonitrile or PAN fibers) are selected to make the NW. Measuring temperature profiles in a heat radiator test; it is revealed that Carbtex NW is an efficient heat barrier. A macroscopic model is then developed to simulate heat transfer in NW (considered as a porous medium) used as a protective heat barrier on aluminum plate. The model is validated comparing experimental results obtained by the heat radiator test and predicted values. The efficiency of NW layer is simulated varying different parameters characteristic of the NW (porosity and heat conductivity) and of the design (thickness of the layer). It is revealed to get good efficiency of the NW heat barrier that heat conductivity of the fibers is crucial to get superior performance as well as high porosity (higher than 0.5) associated with a reasonable thickness of NW (5–7 mm). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Function portability of molecular dynamics on heterogeneous parallel architectures with OpenCL

Classical molecular dynamics simulation for atomistic systems is implemented in OpenCL and benchmarked on a variety of different hardware platforms. Modifying the number of particles and system size in the study provides insight into characteristics of parallel compute platforms, where latency, data transfer, memory access characteristics and compute intense work can be identified as fingerprints in benchmark runs. Data layouts are compared, for which the access of structure-of-arrays shows best performance in most cases. It is demonstrated that function portability can be achieved straightforwardly with OpenCL, while performance portability lacks behind as various architectures strongly depend on specific vectorisation optimisation.     

Does Ergonomics Improve Product Quality and Reduce Costs? A Review Article

Competition is an ongoing challenge confronting industrial corporations, particularly automobile manufacturing. Striving to improve product quality and productivity, automotive industries have used different quality management approaches, such as reduced variability, total quality management, and lean management, over recent years. Furthermore, incorporating proactive ergonomics such as physical and organizational ergonomics and psychosocial factors into the structure of a company is considered to be a support for productivity and quality. Several studies have shown the effects of ergonomics on better quality. Application of both quality management approaches and ergonomics in an integrated manner in the manufacturing production system is emphasized because they are similar concepts with the same objectives, that is, to improve efficiency. In this study, a comprehensive review was undertaken and 25 studies were reviewed in order to define how integration of an ergonomic approach in the manufacturing production system can reduce defects and improve quality in the production process.     

Switching on the photochemical reactivity in heterodimetallic Os–Ru bipyridyl complexes containing a bis(bidentate) phosphine

For the first time the excited states of the RuP₂N₄ moiety belonging to a new heterodimetallic Os^II–Ru^II bipyridyl complex are successfully designed in order to introduce photochemical reactivity. This dramatic effect is achieved via the use of the sterically demanding bis(bidentate) phosphine cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb). Thus, the temperature dependence of the luminescence lifetimes ranging from 77 to 298 K for the novel homodimetallic species meso-(ΔΛ/ΛΔ)-[Os₂(dppcb)(bpy)₄](PF₆)₄ (1) and rac-(ΔΔ/ΛΛ)-[Os₂(dppcb)(bpy)₄](PF₆)₄ (2) clearly indicates that the d–d state responsible for photochemistry is not populated. By contrast, the analogous temperature dependence for the new heterodimetallic species ΔΛ/ΛΔ-[Os(bpy)₂(dppcb)Ru(bpy)₂](PF₆)₄ (3) and ΔΔ/ΛΛ-[Os(bpy)₂(dppcb)Ru(bpy)₂](PF₆)₄ (4) unequivocally shows that as a consequence of the population of the d–d state the photochemical reactivity is switched on. Since single crystal X-ray structure analyses are a major clue to the understanding of photophysical and photochemical properties, also the X-ray structures of 1–3 are given.     

Novel tools for coating developers: a solution to the inverse problem in formulation

The inverse problem in coating formulation, i.e., that of finding a formulation that will satisfy a given set of performance properties, is much more difficult than the direct problem of finding the properties of a given formula. While the latter case may be labor intensive and time-consuming, we have at hand a wealth of test methods that make the solution straightforward. By contrast, the former case calls for experienced formulators plus intensive trial-and-testing work. In this work we describe a way to use intelligent systems in the form of artificial neural networks and genetic algorithms to tackle the more difficult inverse problem. It is applied to a set of five different families of alkyd enamels. In the direct mode, we are able to predict performance of a formulation with 90% efficiency. Through a sensitivity analysis, we can also obtain those variables to which a given property responds more strongly. In the inverse mode, we can obtain enamel formulations that will satisfy a given set of performance requirements. On the whole, it constitutes a powerful lab tool for coating developers. Computer-proposed formulations with some prescribed characteristics and their laboratory tests are discussed. Presented at the 2006 FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans, LA, on November 1–3, 2006. Javier E. Vitela On Sabbatical Leave from Instituto de Ciencias Nucleares, UNAM, 04510 México D.F., México     

Continuous-waveform constant-current isolated physiological stimulator

We have developed an isolated continuous-waveform constant-current physiological stimulator that is powered and controlled by universal serial bus (USB) interface. The stimulator is composed of a custom printed circuit board (PCB), 16-MHz MSP430F2618 microcontroller with two integrated 12-bit digital to analog converters (DAC0, DAC1), high-speed H-Bridge, voltage-controlled current source (VCCS), isolated USB communication and power circuitry, two isolated transistor-transistor logic (TTL) inputs, and a serial 16 × 2 character liquid crystal display. The stimulators are designed to produce current stimuli in the range of ±15 mA indefinitely using a 20V source and to be used in ex vivo cardiac experiments, but they are suitable for use in a wide variety of research or student experiments that require precision control of continuous waveforms or synchronization with external events. The device was designed with customization in mind and has features that allow it to be integrated into current and future experimental setups. Dual TTL inputs allow replacement by two or more traditional stimulators in common experimental configurations. The MSP430 software is written in C++ and compiled with IAR Embedded Workbench 5.20.2. A control program written in C++ runs on a Windows personal computer and has a graphical user interface that allows the user to control all aspects of the device.     

Imidazolium-Based Stabilization of Aqueous Multiwall Carbon Nanotube Dispersions

Imidazolium bromide, an ionic liquid surfactant acrylate, as well as its homopolymer and various copolymers are demonstrated to be superior dispersing aids for preparing aqueous multiwall carbon nanotube (MWCNT) dispersions. We demonstrate apparent complete exfoliation in water with extinction coefficients at 500 nm of about 60 cm² mg⁻¹ of MWCNT dispersed, a new lower bound and the highest reported extinction to date. The efficacy or efficiency of dispersion (activated by ultrasonication) is examined in terms of a quotient of extinction and weight ratio of the active monomer and MWCNT. A rank ordering of the results obtained for seven stabilizers based on the same imidazolium bromide monomer provides insights into roles of π-overlap adsorption onto MWCNT surfaces and how hydrogel properties of some of these polymers provide stability in water at higher concentrations than previously considered feasible for surfactant-stabilized and polymer-stabilized MWCNT dispersions. Simple nanocomposite film formation is demonstrated by casting and thermal diffusivity and electrical conductivity properties are examined.     

Influence of ionic pretreatment on the performance of solid electrolyte dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) were manufactured with liquid iodine/iodide electrolyte solution in acetonitrile and a solid electrolyte based on plasticized poly(ethylene oxide) (PEO). Two types of titania electrodes manufactured from two-ingredient precursors were used to assess the efficacy of the solid electrolyte and the improvement produced by two chemical treatments. Solid electrolyte devices with a liquid electrolyte pretreatment applied to the electrolyte-oxide interface demonstrated improved photovoltaic performance compared to untreated solid electrolyte devices and solid electrolyte devices given an electrode-bulking sol treatment. Devices using electrodes made from hydrothermally synthesized titanate nanotubes resulted in lower performance than those made from the typically-used titania nanopowder, with significant performance loss resulting from the substitution of solid for liquid electrolyte, indicating the critical dependence of performance on electrolyte infiltration into the oxide layer.