Plane wave spectrum theory applied to nearfield measurements for electromagnetic compatibility investigations

Electromagnetic near-field measurement is commonly used to characterise radiated emissions of electronic devices and to study interferences between components and systems. To reduce the number of measurements that usually take a long time, the authors apply a post-processing technique based on the plane wave spectrum (PWS) theory. This post-processing enables the computation of the magnetic field at various distances above the device from two planar measurements only. The authors first present the theory of the PWS approach and in a second step, it is applied to a passive circuit to validate the process. Finally, post-processing is applied to an active circuit.     

Master production schedule time interval strategies in make-to-order supply chains¶

While the literature primarily addresses MPS design from the manufacturer's perspective, this research considers MPS policy design in a two-stage rolling schedule environment with a particular focus on the policy governing schedule flexibility in the non-frozen time interval (i.e. liquid versus slushy orders). Using computer simulation, we experimentally evaluate the impact of four MPS design factors (non-frozen interval policy, planning horizon length, frozen interval length and re-planning frequency) and four environmental factors (natural order cycle length, vendor flexibility, demand range and demand lumpiness) on MPS schedule cost and instability. The experimental design considers the often-conflicting impact of MPS policy on the channel members by capturing performance metrics at the manufacturer, vendor and system level. The research findings indicate that moving from a liquid to a slushy non-interval strategy increases the manufacturer's costs, but may result in an even greater cost reduction for the vendor resulting in lower system costs. The economic benefit of the slushy strategy is directly tied to the vendor's relative flexibility in responding to the manufacturer's orders on a lot-for-lot basis. High vendor flexibility favours the liquid strategy, while low vendor flexibility favours the slushy strategy.     

EFFECTS OF pH,INITIATOR, SCAVENGER,AND SURFACTANT ON THE OZONATION MECHANISM OF AN AZO DYE (ACID RED-151) IN A BATCH REACTOR

In this study, an initiator (Fe²⁺) and a scavenger (CO₃ ^2?) were used at different concentrations in a batch reactor to investigate the reaction mechanism of ozonation of a model azo dye, namely Acid Red-151 (AR-151). Also, the effect of a nonionic surfactant known as a major pollutant in many industrial wastewaters, namely polyethylene glycol (PEG), was observed on the degradation rate of AR-151. The experimental parameters and their ranges were: pH (2.5–10), initiator (0.8–50 mg/L of Fe²⁺), surfactant (10–200 mg/L of PEG), and scavenger (10–500 mg/L of CO₃ ^2?); the initial concentration of the azo dye was kept constant at 20 mg/L in all the experiments. Results showed that decomposition of ozone was enhanced with increasing pH and increasing initiator (Fe²⁺) concentration at a scavenger concentration of 100 mg/L, when there is no dye in the medium. A scavenger concentration of 100 mg/L CO₃ ^2? was not sufficient to terminate the chain reactions of ozone decomposition. It was concluded that the dominant mechanism in the degradation of AR-151 was its direct oxidation with ozone molecules in water. The data obtained for the dye and chemical oxygen demand (COD) removals and total oxidation rate constants at different operating conditions were assessed in order to estimate the possible contribution of dye-oxidation by free radicals.     

A heuristic approach for allocation of data to RFID tags: A data allocation knapsack problem (DAKP)

Durable products and their components are increasingly being equipped with one of several forms of automatic identification technology such as radio frequency identification (RFID). This technology enables data collection, storage, and transmission of product information throughout its life cycle. Ideally all available relevant information could be stored on RFID tags with new information being added to the tags as it becomes available. However, because of the finite memory capacity of RFID tags along with the magnitude of potential lifecycle data, users need to be more selective in data allocation. In this research, the data allocation problem is modeled as a variant of the nonlinear knapsack problem. The objective is to determine the number of items to place on the tag such that the value of the “unexplained” data left off the tag is minimized. A binary encoded genetic algorithm is proposed and an extensive computational study is performed to illustrate the effectiveness of this approach. Additionally, we discuss some properties of the optimal solution which can be effective in solving more difficult problem instances.     

An intelligent approach to supplier evaluation in automotive sector

During the process of supplier evaluation, selecting the best desirable supplier is one of the most critical problems of companies since improperly selected suppliers may cause losing time, cost and market share of a company. For this multiple-criteria decision making selection problem, in this paper, a fuzzy extension of analytic network process (ANP), which uses uncertain human preferences as input information in the decision-making process, is applied since conventional methods such as analytic hierarchy process cannot accommodate the variety of interactions, dependencies and feedback between higher and lower level elements. The resulting fuzzy ANP enhances the potential of the conventional ANP for dealing with imprecise and uncertain human comparison judgments. In short, in this paper, an intelligent approach to supplier selection problem through fuzzy ANP is proposed by taking into consideration quantitative and qualitative elements to evaluate supplier alternatives, and a case study in automotive sector is presented.     

Stress Intensity Factor <Emphasis Type="Italic">K</Emphasis><Subscript>I</Subscript> and <Emphasis Type="Italic">T</Emphasis>-Stress Determination in HDPE Material

For the characterization of high-density polyethylene (HDPE) pipes according to the operating conditions, the Nol ring test is an adequate method to rapidly and inexpensively determine the mechanical properties with good effectiveness. In this work, Nol ring tests will be carried out on HDPE material with different crack depth ratios. Based on these results, the brittle fracture of HDPE will be studied and a new experimental technique for measuring stress intensity factor (SIF) and T-stress under mode I conditions is developed. The formulation of the normal strains, close to the crack tip, is given using the first five terms of the generalized Westergaard formulation. Then, in a second step, these formulations are applied to analytically determine the optimum locations for the rectangular rosette to eliminate the errors due to higher order terms of the asymptotic expansion.