Peroxodisulfate generation on boron-doped diamond microelectrodes array and detection by scanning electrochemical microscopy

In this work, the electrogeneration of peroxodisulfate from a 1 M H₂SO₄ solution on boron-doped diamond microelectrodes array has been studied. The peroxodisulfate is detected at the vicinity of the boron doped diamond electrode, with the SECM probe, only when the polarization of the microarray is greater than 2.1 V versus AgCl/Ag. The main electrochemical interest of working with microarrays comes from the fact that current densities and efficiencies are comparable to those observed in the peroxodisulfate industrial production. The local Scanning Electrochemical Microscopy studies have shown that the peroxodisulfate reaction is related to a surface mediated oxidation of sulfate anions into peroxodisulfate according to a complex reactional mechanism.     

Synthesis of ZSM‐5 by hydrothermal method with pre‐mixing in a stirred‐tank reactor

This work proposed a synthesis route of ZSM‐5 via the hydrothermal method with premixing in a stirred tank reactor (STR). Effects of various operating conditions, including pre‐mixing time, molar ratio of SiO₂/Al₂O₃, TPAOH (organic template agents) concentration, NaCl (alkali metal cations) concentration, crystallization temperature, and crystallization reaction time, on the average particle size (PS) and particle size distribution (PSD) were investigated. It was found that the pre‐mixing time in the STR significantly affect the formation of proto‐nuclei in premixing process and crystal growth in hydrothermal reaction process, and consequently influence the PS and PSD of the prepared ZSM‐5. ZSM‐5 with good thermal stability, a PS of 380 nm, PSD of 0.17–0.9 µm, pore diameter of 2.31 nm, pore volume of 0.19 cm³ · g^?1 and specific surface area of 337.25 m² · g^?1 were obtained under the optimal conditions of a crystallization reaction time of 24 h, a crystallization temperature of 130 °C, a molar ratio of SiO₂/Al₂O₃ of 200, a TPAOH concentration of 3.5 mol · L^?1, NaCl concentration of 0.3 mol · L^?1, and a pre‐mixing time of 5 h. This work indicated that the operating conditions including premixing time have a significant effect on its PS and PSD.     

1.3 /spl mu/m double quantum well GaInNAs distributed feedback laser diode with 13.8 GHz small signal modulation bandwidth

A report is presented on continuous-wave (CW) singlemode operation of a distributed feedback GaInAsN laser diode at 1295 nm. A sidemode supression ratio of 43 dB is obtained at 60 mA drive current. Small signal modulation bandwidth measurements show a record 3 dB cutoff frequency of 13.8 GHz.     

Fault diagnosis system for tapped power transmission lines

This paper presents a design for a fault diagnosis system (FDS) for tapped HV/EHV power transmission lines. These lines have two different protection zones. The proposed approach reduces the cost and the complexity of the FDS for these types of lines. The FDS consists basically of fifteen artificial neural networks (ANNs). The FDS basic objectives are mainly: (1) the detection of the system fault; (2) the localization of the faulted zone; (3) the classification of the fault type; and finally (4) the identification of the faulted phase. This FDS is structured in a three hierarchical levels. In the first level, a preprocessing unit to the input data is performed. An ANN, in the second level, is designed in order to detect and zone localize the line faults. In the third level, two zone diagnosis systems (ZDS) are designed. Each ZDS is dedicated to one zone and consists of seven parallel-cascaded ANN's. Four-parallel ANN's are designed in order to achieve the fault type classification. While, the other three cascaded ANN's are designed mainly for the selection of the faulted phase. A smoothing unit is also configured to smooth out the output response of the proposed FDS.     

Multivariate cubic spline smoothing in multiple prediction.

Given longitudinal data for several variables, including a given outcome variable, it is desired to predict the outcome for a specific individual, or more generally experimental unit, in such a way that the predicted value is both accurate and resistant (i.e. has good cross-validation). There are certain data-analytic difficulties associated with long-term multivariate longitudinal data that must be overcome in the prediction process. This paper provides a program written in the Statistical Analysis System (SAS) programming language, based generally on the Roche-Wainer-Thissen stature prediction model, that enables the researcher to overcome these difficulties.     

Interpretation of way-finding healthcare symbols by a multicultural population: Navigation signage design for global health

The interpretation of way-finding symbols for healthcare facilities in a multicultural community was assessed in a cross-sectional study. One hundred participants recruited from Al Ain city in the United Arab Emirates were asked to interpret 28 healthcare symbols developed at Hablamos Juntos (such as vaccinations and laboratory) as well as 18 general-purpose symbols (such as elevators and restrooms). The mean age was 27.6 years (16–55 years) of whom 84 (84%) were females. Healthcare symbols were more difficult to comprehend than general-purpose signs. Symbols referring to abstract concepts were the most misinterpreted including oncology, diabetes education, outpatient clinic, interpretive services, pharmacy, internal medicine, registration, social services, obstetrics and gynecology, pediatrics and infectious diseases. Interpretation rates varied across cultural backgrounds and increased with higher education and younger age. Signage within healthcare facilities should be tested among older persons, those with limited literacy and across a wide range of cultures.     

A Wireless Instructor System for Computer-Supported Collaborative Learning Requiring Immersive Presence (CSCLIP)

The Computer-Supported Collaborative Learning Requiring Immersive Presence (CSCLIP) concept has been established with the objective of extending and enhancing thee-learning experience of distance education, especially for classes that involve laboratory (lab) experiments. The CSCLIP concept defines immersive presence as an inherent requirement that enables cognitive, affective, and most importantly psychomotor learning objectives to integrate into designs and concepts for next generation e-learning systems (Sharda et~al., 2003). Within the CSCLIP architectural framework, the Wireless Instructor (WI) system has been conceptualized and developed as an essential device to effectively support teaching while roaming instructional features for both local and distance students. The WI system provides cost effective means to establish a real-time immersive presence for the distance learning (DL) student and his/her lab group peers. The technical design and system architecture to create a WI system are introduced in this paper. The objective of the WI system is to make the learning experience more vivid and interactive by enabling the DL students, as well as the local students that are not in the same room with the instructor(s) at the same time, to be able to flexibly interact with the instructor(s) in real-time. With this system the students can experience real-time or non-real-time virtual tours with the instructor(s), enabling the students to visit places that may not be easily accessible due to distance, limited space and/or time, cost, or possible danger. The WI system consists of two major sub-components. First is a wireless audio and video (AV) system, which transfers real-time AV signals to and from the instructor(s) to all students. Second is the wireless instructor locator & data assistant system. These two systems can be combined into one WI unit, but as the applied development technologies are somewhat distinct, their features and architectural designs will be described separately throughout this paper. Integration of the two systems will enable further capabilities.This revised version was published online in March 2005 with corrections to the cover dateThis project was funded by the U.S. Department of Education (DoE) award no. P116Z020042 project titled Telecommunications Virtual Laboratory Development.     

Macsyma: A personal history

The Macsyma system arose out of research on mathematical software in the AI group at MIT in the 1960s. Algorithm development in symbolic integration and simplification arose out of the interest of people, such as the author, who were also mathematics students. The later development of algorithms for the GCD of sparse polynomials, for example, arose out of the needs of our user community. During various times in the 1970s the computer on which Macsyma ran was one of the most popular nodes on the ARPANET. We discuss the attempts in the late 70s and the 80s to develop Macsyma systems that ran on popular computer architectures. Finally, we discuss the impact of the fundamental ideas in Macsyma on the author’s current research on large scale engineering and socio-technical systems.     

3D Shape Recovery of Smooth Surfaces: Dropping the Fixed-Viewpoint Assumption

We present a new method for recovering the 3D shape of a featureless smooth surface from three or more calibrated images illuminated by different light sources (three of them are independent). This method is unique in its ability to handle images taken from unconstrained perspective viewpoints and unconstrained illumination directions. The correspondence between such images is hard to compute and no other known method can handle this problem locally from a small number of images. Our method combines geometric and photometric information in order to recover dense correspondence between the images and accurately computes the 3D shape. Only a single pass starting at one point and local computation are used. This is in contrast to methods that use the occluding contours recovered from many images to initialize and constrain an optimization process. The output of our method can be used to initialize such processes. In the special case of fixed viewpoint, the proposed method becomes a new perspective photometric stereo algorithm. Nevertheless, the introduction of the multiview setup, self-occlusions, and regions close to the occluding boundaries are better handled, and the method is more robust to noise than photometric stereo. Experimental results are presented for simulated and real images.     

Should we try to measure software quality attributes directly?

Most external software quality attributes are conceptually subjective. For example, maintainability is an external software quality attribute, and it is subjective because interpersonally agreed definitions for the attribute include the phrase ‘the ease with which maintenance tasks can be performed’. Subjectivity clearly makes measurement of the attributes and validation of prediction systems for the attributes problematic. In fact, in spite of the definitions, few statistically valid attempts at determining the predictive capability of prediction systems for external quality attributes have been published. When validations have been attempted, one approach used is to ask experts to indicate if the values provided by the prediction system informally agree with the experts’ intuition. These attempts are undertaken without determining, independently of the prediction system, whether the experts are capable of direct consistent measurement of the attribute. Hence, a statistically valid and unbiased estimate of the predictive capability of the prediction system cannot be obtained (because the experts’ measurement process is not independent of the prediction system’s values). In this paper, it is argued that the problem of subjective measurement of quality attributes should not be ignored if quality is to be introduced into software in a controlled way. Further, it is argued that direct measurement of quality attributes should be encouraged and that in fact such measurement can be quantified to establish consistency using an existing approach. However, the approach needs to be made more accessible to promote its use. In so doing, it would be possible to decide whether consistent independent estimates of the true values of software quality attributes can be assigned and prediction systems for quality attributes developed.