Multiple-source, multiple-frequency error of an electric field meter

Electric field meters (EFM's) are typically calibrated using single-frequency, single-source standard fields. The response to multiple sources or nonsinusoidal time dependence may be different, however. Possible errors in a multiple-source, multiple-frequency environment are analyzed for an EFM consisting of an electrically short dipole antenna with a diode load and a radio-frequency (RF) filter transmission line. Also considered are errors in the assumption of equal electric and magnetic energy densities in a multiple plane-wave environment. Typical errors of field-intensity measurements are about one to 3 dB, but in some circumstances they can exceed 10 dB.     

Catalogue of electromagnetic environment measurements, 30-300 Hz

The IEEE Electromagnetic Compatibility Society's Technical Committee on Electromagnetic Environments (TC-3) has undertaken a long-term project to compile an inventory or catalogue of published measurements of electromagnetic environments. The frequency spectrum has been divided into tractable bands which will be considered one at a time. We have now completed the 30-300 Hz band. This paper presents the resulting bibliography, along with a brief overview of what has been measured     

PWM-switching pattern-based diagnosis scheme for single and multiple open-switch damages in VSI-fed induction motor drives

This paper deals with a fault detection technique for insulated-gate bipolar transistors (IGBTs) open-circuit faults in voltage source inverter (VSI)-fed induction motor drives. The novelty of this idea consists in analyzing the pulse-width modulation (PWM) switching signals and the line-to-line voltage levels during the switching times, under both healthy and faulty operating conditions. The proposed method requires line-to-line voltage measurement, which provides information about switching states and is not affected by the load. The fault diagnosis scheme is achieved using simple hardware and can be included in the existing inverter system without any difficulty. In addition, it allows not only accurate single and multiple faults diagnosis but also minimization of the fault detection time to a maximum of one switching period (T(c)). Simulated and experimental results on a 3-kW squirrel-cage induction motor drive are displayed to validate the feasibility and the effectiveness of the proposed strategy.     

Are Two Better Than One? A Comparison Between Single- and Dual-Monitor Work Stations in Productivity and User’s Windows Management Style

Multiple monitors are commonly used in the workplace nowadays. This study compares user productivity and windows management style (WMS) on single- and dual-monitor work stations for engineering tasks of three complexity levels. Four productivity measures including task time, cursor movement, the number of window switches, and the number of mouse clicks were compared. The results showed that dual-monitor setting resulted in significantly less window switches and mouse clicks. Most users preferred dual-monitor setting. To understand how users manage multiple windows in completing their tasks, a new WMS categorization method is proposed, toggler and resizer, and user behavior was categorized into one of these two styles. More users adopted “toggler” style, but as the task complexity level increased, some “toggler” style users switched to “resizer” style.     

Real-time monitoring of peanut drying parameters in semitrailers

Knowledge of peanut drying parameters, such as temperature and relative humidity of the ambient air, temperature and relative humidity of the air being blown into the peanuts, and kernel moisture content, is essential in managing the dryer for optimal drying rate. The optimal drying rate is required to preserve quality and desired flavor. In the current peanut-drying process, such parameters are elusive in real time and are either not measured or only measured periodically by an operator. A peanut-drying monitoring system, controlled by an embedded microcontroller and consisting of relative humidity and temperature sensors and a microwave peanut moisture sensor, was developed to monitor drying parameters in real time. It was deployed during the 2014 peanut harvest season at a peanut buying point in central Georgia, USA. It was placed in 45-ft (13.7-m) drying semitrailers to monitor in-shell kernel moisture content, temperature of the drying peanuts, temperature, and relative humidity of the exhaust air from the peanuts and relative humidity of the air being blown into the peanuts in real time. In-shell kernel moisture content was determined with a standard error of performance of 0.55% moisture content when compared to the reference oven-drying method. Data from drying parameters were time-stamped and stored on a CompactFlash card every 12?s and were used to assess the efficiency of dryer control settings. Ambient air conditions were measured by an on-site weather station. Results of the study support the value of such a monitoring system and show that implementation of the system for dryer control has the potential for saving a buying point, in the current economical context, as much as $22,000 annually in costs of electric energy and propane.     

Surface evaluation and electrochemical behaviour of doped silane pre-treatments on galvanised steel substrates

The present work aims at evaluating the surface morphology and the corrosion resistance of galvanised steel substrates pre-treated with bis-[triethoxysilylpropyl] tetrasulfide silane (BTESPT) solutions doped with cerium nitrate or zirconium nitrate. The silane pre-treatment leads to the formation of a silane coating in the metallic surface. The surface morphology of this coating was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM).     

Modification of bis-silane solutions with rare-earth cations for improved corrosion protection of galvanized steel substrates

Chemical formulations based on silane solutions are currently used for the pre-treatment of metallic substrates. These pre-treatments provide corrosion protection of the metallic substrates due to the good barrier properties of the silane films that form on the surface. The corrosion protection of silane-based pre-treatments can be improved by adding dopants to the silane solutions. The dopants must present corrosion inhibition properties and must keep or improve the barrier properties of the silane film without modification of surface functionality and bulk properties.     

Widgets Dedicated to User Interface Evaluation

In this article, evaluation-based widgets are proposed as a contribution to assist evaluators for early evaluation of user interfaces. This contribution imbricates the ergonomic quality evaluation process into widgets used for user-interface graphical composition. In other words, these widgets evaluate themselves according to a defined set of ergonomic guidelines. The proposed widgets indicate the possible interface design ergonomic inconsistencies as a notification to the designer. The guidelines set can be modified through an interface dedicated to guidelines definition into XML files. The proposed widgets are intended for the evaluation of different kind of user interfaces: WIMP, web, and mobile. An experimental evaluation, involving these evaluation-based widgets, is proposed to illustrate and to validate the approach.     

New calibration technique for microwave moisture sensors

A new calibration technique was developed for implementation with microwave moisture sensors. The calibration permittivity function used for this purpose allows computation of moisture content in granular materials with significant differences in shape, dimensions, and composition, independent of bulk density and with temperature compensation. A 3D representation is used to plot the calibration permittivity function as it depends on temperature and moisture content in wheat and corn. For each material, data points form a plane surface. These planes have nearly the same coefficients, which can be utilized for the development of a “universal” calibration method for moisture sensing in natural and manufactured granular materials. Foundations of the method are discussed based on results obtained for wheat and corn over a wide temperature range and at moisture contents of practical interest