STLS Algorithm for Power-Quality Indices Estimation

This paper introduces a new two-stage, self-tuning least-squares digital signal processing algorithm for power-quality (PQ) indices estimation according to the power components and PQ indices definitions given in the IEEE Standard 1459-2000. The algorithm is based on the nonrecursive least error square technique accompanied with an tuning procedure, which generally improves the algorithm properties: the measurement range, the immunity to a random noise, convergence, and accuracy. The presented algorithm models typical signal distortions and it can be used for the real-time PQ indices estimation. In order to estimate signal spectra and fundamental frequency, current and voltage signals are processed in the first algorithm stage, whereas in the second stage, the power components and PQ indices are calculated based on the results obtained from the first stage. To demonstrate the efficiency of the proposed algorithm, the results of computer simulated and laboratory tests are presented.     

Single-Layer Evapotranspiration Model with Variable Canopy Resistance

A new approach to modeling canopy resistance is presented as an alternative to the Food and Agricultural Organization of the United Nations Penman-Monteith method with the constant canopy resistance. The evapotranspiration (ET) model is based on the “big-leaf” approach and a variable canopy resistance. The model's input requires standard meteorological data as in the Penman-Monteith combination approach. The model was validated using weather and grass lysimeter data measured on an hourly basis at Davis, Calif., and on a daily basis at Policoro, Southern Italy. ET estimates from the model were compared with the results of ET values obtained by the Food and Agricultural Organization of the United Nations Penman-Monteith approach using the constant canopy resistance rc = 70 s m?1. The results showed a very convincing performance of the model for estimating reference ET on both an hourly and daily basis. This work confirms that the canopy resistance depends on climate, and that a variable rc is recommended for ET models. The proposed model does not introduce any empirical parameter, does not require calibration for the two sites tested or for different time scales, and it is simple enough for direct practical application.     

Preparation and characterization of cysteine‐formaldehyde cross‐linked complex for CO2 capture

This work focused on the preparation and characterization of cysteine‐formaldehyde cross‐linked complex derived from cysteine hydrochloride and formaldehyde. The cross‐linked complex was prepared based on the nucleophilic substitution reaction of cysteine with formaldehyde accompanied by π bond breakage of carbonyl from formaldehyde. Meanwhile, its surface morphology, element composition, group distribution, and thermodynamics were experimentally investigated by means of SEM, XRD, EA, EDS, ¹H‐NMR, FTIR, BET, and TGA as well as an analysis of the characteristics of CO₂ adsorption. The results indicated that the as‐prepared cross‐linked complex exhibited a rod‐shaped hollow crystal structure with a lateral distribution of sulphur and nitrogen atoms toward the crystal surface. As a mesoporous crystal material, the cross‐linked complex presented a four‐step (amide forming, fast pyrolysis, slow pyrolysis, and dehydrogenation) pyrolysis above 430 K, yet possessed a relatively acceptable thermodynamic stability below 430 K. In addition, the interaction mechanism between the cysteine hydrochloride and formaldehyde was revealed by characteristics and simulation.     

Degradation of adhesive composites

Composite materials consisting of natural leather and polyurethane elastomers, and bonded together by polyurethan adhesives, were submitted to accelerated ageing at various testing conditions. The extent of the degradation of these composites was evaluated through the determination of mechanical strength reduction and through the insight into the structural and chemical transformations of the adhesive polymeric materials. Founded data correlations indicate to the mechanism and to the relevant factors that influence of ageing processes.     

Factors influencing ATM adapter throughput

Analytical and experimental evaluations show that ATM adapters can perform quite close to their designed limits, provided that they are used in a properly configured environment with series resources capable of sustaining the desired throughputs. While the media speed may be 155, 100 or 25 Mbps, there are a number of factors that will determine the final achieved maximum throughput observed by a user of a ATM adapter. One is the overhead inherent to ATM, such as the 5 byte ATM header that accompanies every 48 bytes of data sent. Others are inherent in the protocol used in the communication layers above ATM (e.g., pacing and retransmission associated with TCP/IP). Still others are dependent upon the processor speed and operating system used by the adapter host system. This paper discusses those parameters that, based on our experience, can have a considerable impact on the throughput of an ATM adapter. Turboways¹ 25, 100 and 155 ATM adapter measurements illustrate these issues. These represent end-to-end (application layer-to-application layer) throughput measurements, involving all supporting hardware (workstations, 8260 ATM hub/switch, 8282 ATM concentrator, etc.) and all protocol layers, operating system, etc.This work was supported in part through the 1994 and 1995 IBM SUR grants, the IBM-NCSU ATM partnership effort and NSF award ACS-9418960.     

Hardware Realization of a Java Virtual Machine for High Performance Multimedia Applications

This paper describes a new architecture for JAVA-based, interactive multimedia applications. A hardware implementation of a Java Virtual Machine (JVM) is proposed, which allows the direct execution of Java bytecode. In a single clock cycle, up to 3 bytecode instructions can be decoded and executed in parallel using a RISC pipeline. A splitable 64-bit ALU implementation addresses demanding processing requirements of typical multimedia signal processing schemes. The on-chip caches are adapted to the specific data structures of the JVM. The proposed architecture supports execution of multiple Java threads in parallel. An implementation of basic building blocks of the processor with a standard-cell library provides an estimate of 150 MHz clock-speed for a 0.35 m 3 metal layer CMOS process. With a size of less than 10 mm² needed for the core logic, it is possible to integrate multiple JVMs together with larger cache memories on a single chip. Based on these results, we discuss various performance aspects of JAVA for use in future multimedia terminals.     

Complexity-based quality indicators for human and social capital in science and research: the case of Serbian Homeland versus Diaspora

Scientometrics - We developed quality indicators model for measuring human and social capital in the scientific and research communities, grounded in the complexity science. The model was...     

Influences of Detection Pinhole and Sample Flow on Thermal Lens Detection in Microfluidic Systems

Thermal lens microscopy (TLM), due to its high temporal (\({\sim }\mathrm{ms}\)) and spatial resolution (\({\sim }\upmu \mathrm{m}\)), has been coupled to lab-on-chip chemistry for detection of a variety of compounds in chemical or biological fields. Due to the very short optical path length (usually below 100 \(\upmu \mathrm{m}\)) in a microchip, the sensitivity of TLM is unfortunately still 10 to 100 times lower than conventional TLS with 1 cm sample length. Optimization of the TLM optical configuration was made with respect to different pinhole aperture-to-beam size ratios for the best signal-to-noise ratio. In the static mode, the instrumental noise comes mainly from the shot noise of the probe beam when the chopper frequency is over 1 kHz or from the flicker noise of the probe beam at low frequencies. In the flowing mode, the flow-induced noise becomes dominant when the flow rate is high. At a given flow rate, fluids with a higher density and/or a higher viscosity will cause larger flow-induced noise. As an application, a combined microfluidic flow injection analysis (\(\upmu \mathrm{FIA}\))–TLM device was developed for rapid determination of pollutants by colorimetric reactions. Hexavalent chromium [Cr(VI)] was measured as a model analyte. Analytical signals for 12 sample injections in 1 min have been recorded by the \({\upmu }\)FIA–TLM. For injections of sub-\(\upmu \)L samples into the microfluidic stream in a \(50\,\upmu \mathrm{m}\) deep microchannel, a limit of detection of \(4\,\mathrm{ng}{\cdot }\mathrm{mL}^{-1}\) was achieved for Cr(VI) in water at 60 mW excitation power.     

Optimization of a Thermal Lens Microscope for Detection in a Microfluidic Chip

The optical configuration of a thermal lens microscope (TLM) was optimized for detection in a microfluidic chip with respect to the flow velocity, and the pump and probe beam parameters (beam waists, offsets, and mode mismatching degree). It was found that an appropriate pump–probe beam offset for a certain flow velocity would provide not only a higher sensitivity but also a better response linearity of TLM over three orders of magnitude of sample concentration. Diffraction-limited pump beam excitation is advantageous for space-resolved measurement, while a larger pump beam with 10 times lower power density is favorable for higher sensitivity at given experimental conditions. As an application, TLM was used to study the diffusion of azobenzene in a microfluidic chip. Diffusion profiles at different distances from the mixing point were recorded by scanning the TL signal along the cross section of the microchannel. By fitting the diffusion profiles to a theoretical model of mass transfer in a microchannel, diffusion coefficients of azobenzene in octane and methanol were determined to be \(5\times 10^{-10}\,\hbox {m}^{2}{\cdot }\,\hbox {s}^{-1}\) and \(6\times 10^{-10}\,\hbox {m}^{2}{\cdot }\,\hbox {s}^{-1}\) , respectively.     

Thermal Properties of Surface-Modified \upalpha - and \upvarepsilon -Fe_{2}\hbox {O}_{3} Photocatalysts Determined by Beam Deflection Spectroscopy

In this work, a photothermal beam deflection spectroscopy setup is developed and applied for determination of the thermal parameters (thermal diffusivity and thermal conductivity) of \(\upalpha \) - and \(\upvarepsilon \) -Fe \(_{2}\hbox {O}_{3}\) nanodeposits on Si(100) substrates, specifically designed and tested as photocatalysts. It was observed that thermal parameters of the material strongly depend on the sample composition and morphology, which affect also the photocatalytic activity. The correlation between the thermal and photocatalytic properties are critically discussed based on the characteristics of the materials.