Formability and uniformity aspects in drawbead controlled geometries

This paper examines the role of drawbead design within tooling design and stamping engineering, as a system. A microcomputer based program DRAWBD is used to illustrate the effect of tooling adjustments beyond and within the trim line, the variability of material and lubricant on the part thickness, as well as stress and moment distributions. The paper illustrates that the interactions between the different tooling and operational parameters are very complex, and demonstrates the difficulty in troubleshooting drawbead controlled stamping systems. The conclusion is that the goal in stamping should be to maintain control over the tooling, process, and material windows, and accordingly over uniformity and consistency of interacting parameters.     

Experimental and numerical analysis of electrical metal foam heater

A novel concept of air heater using a heating element made from Aluminum metal porous disc surrounded by a DC resistive electrical heater inserted in the mid-plane of a copper tube of (52.8 mm) diameter and (480 mm) length is presented herein. Study of the developed heater is conducted; using different porous disc thicknesses of (20, 40, 60 mm), heater wall temperatures (106 °C and 119 °C), and flow rates rare varied from (100-300 L/min). Al-metal foam disc has been made using the metal powder technology. Different resistive electrical heaters according to the type of porous disc used have been manufactured. A 2-D computational model is developed, using continuity, momentum, and energy equations for turbulent forced flow in plain tube, while adopting Darcy’s model in the porous disc region.     

Treatment of dye and cadmium solutions using asymmetric kaolin porous tubular support

Kaolin porous support ceramic was prepared from kaolin. The characterization of the porous properties and structure of the support synthesis was carried out by scanning electron microscopy (SEM), absorption rate, shrinkage rate and Hg-porosimetry methods. The pore size distribution showed a unimodal pore size distribution with an average pore size of about 0.9 µm. The reliability of support was measured by filtration tests and removal of heavy metals.Filtration studies using porous tubular supports were performed for solutions containing methylene blue and Evans blue. The study of the liquid filtration and flow through these supports showed that the methylene blue rejection rate was 99% while the Evans blue rate reached 90% for a 90 minute filtration time under a pressure of 2 bar. We beforehand tested the flow rate for each support with distilled water and the results show that the support of kaolin gave a flux for distilled water of 31.0 L/h at the pressure of 2 bar. At a pressure of 3.5 bar an increase in the distilled water flux through the support was observed.The rejection rate of cadmium ions was more significant. A rejection rate of 99.99% using a 10^− 4 mol/L solution of this heavy metal for two-hour treatment time was obtained.     

Using the BCD model for risk analysis: An influence diagram based approach

In this paper, we are interested in addressing risk analysis. We propose an influence diagram-based approach that focuses on a Benefit, Cost, Deficit (BCD) model. The BCD model is proposed for studying the intentional deviant behaviors of human operators in a system. In this model, the consequences of human actions are analyzed with respect to three parameters: benefit, cost and deficit. Our approach aims to expand the BCD model by integrating factors, such as those related to the organization of the system in question, that influence human operator actions. In addition, the approach considers multiple criteria that are related, for example, to safety and productivity. To build a model that evaluates the risk induced by human actions in a system and analyzes the impact of the different factors, we use influence diagrams. Influence diagrams are probabilistic graphical models that can deal with uncertainty and with incomplete and imprecise information. Influence diagrams also represent the interdependencies between the different variables of the studied problem. In addition, contrary to Bayesian networks, influence diagrams can rank a set of actions by providing information on which action carries the greatest risk or the most benefits. We applied this approach to a case study of an industrial rotary press, but it can also be used in other problems and sectors.     

High performers in complex spatial systems: a self-organizing mapping approach with reference to The Netherlands

This paper addresses the performance of creative firms from the perspective of complex spatial systems. Based on an extensive high-dimensional database on both the attributes of individual creative firms in the Netherlands and a series of detailed regional facilitating and driving factors related, inter alia, to talent, innovation, skills, networks, accessibility and hardware, a new methodology called self-organizing mapping is applied to identify and explain in virtual topological space, the relative differences between these firms and their business performance in various regions. It turns out that there are significant differences in the spatial and functional profile of large firms vis-à-vis SMEs across distinct geographical areas in the country.     

Management of Multimedia Scenarios in an Object-Oriented Database System

In this paper, we present an approach to multimedia scenario management in a database system that considers : object-oriented concepts for multimedia and scenario modeling; both known and unknown multimedia object playing duration; temporal specification language; Petri net automatic generation based on temporal specifications; automatic detection of user temporal specification errors and contradictions; and finally user interactions based on composite Petri net features.     

A Bayesian network for recurrent multi-criteria and multi-attribute decision problems: Choosing a manual wheelchair

This paper discusses recurrent multi-criteria, multi-attribute decision problems. Because of the possibility of decision-maker ignorance or low decision-maker involvement the decision problem structuring is done once for all by a group of experts and does not involve the implication of the decision makers. We propose an original model based on Bayesian networks, which provides a decision process that helps the decision-maker to select an appropriate alternative among a set of alternatives, taking into account multiple criteria that are often conflicting. Our model makes it possible to represent in the same model the decision case (i.e., the decision-maker characteristics, contextual characteristics, their needs and preferences), the set of alternatives with the different attributes, and the choice criteria. The model allows us to compute the value of three essential elements: the importance of each criterion, which is based on the decision-case characteristics; each criterion’s evaluation index in terms of the alternative; and each criterion’s satisfaction index. The recurrent problem of choosing a manual wheelchair (MWC) illustrates the construction and use of our model.     

Assessment of ship manoeuvrability by using a coupling between a nonlinear transient manoeuvring model and mathematical programming techmques

In this paper, a numerical method based on a coupling between a mathematical model of nonlinear transient ship manoeuvring motion in the horizontal plane and Mathematical Programming （MP） techniques is proposed. The aim of the proposed procedure is an efficient estimation of optimal ship hydrodynamic parameters in a dynamic model at the early design stage. The proposed procedure has been validated through turning circle and zigzag manoeuvres based on experimental data of sea trials of the 190 000- dwt oil tanker. Comparisons between experimental and computed data show a good agreement of overall tendency in manoeuvring traiectories.     

Privacy aware group based recommender system in multimedia services

Multimedia Tools and Applications - Recommending similar-interest users’ groups in multimedia services is the problem of detecting for each registered user his/her membership to one...     

Triphenylene‐Derived Electron Acceptors and Donors on Ag(111): Formation of Intermolecular Charge‐Transfer Complexes with Common Unoccupied Molecular States

Over the past years, ultrathin films consisting of electron donating and accepting molecules have attracted increasing attention due to their potential usage in optoelectronic devices. Key parameters for understanding and tuning their performance are intermolecular and molecule–substrate interactions. Here, the formation of a monolayer thick blend of triphenylene‐based organic donor and acceptor molecules from 2,3,6,7,10,11‐hexamethoxytriphenylene (HAT) and 1,4,5,8,9,12‐hexaazatriphenylenehexacarbonitrile (HATCN), respectively, on a silver (111) surface is reported. Scanning tunneling microscopy and spectroscopy, valence and core level photoelectron spectroscopy, as well as low‐energy electron diffraction measurements are used, complemented by density functional theory calculations, to investigate both the electronic and structural properties of the homomolecular as well as the intermixed layers. The donor molecules are weakly interacting with the Ag(111) surface, while the acceptor molecules show a strong interaction with the substrate leading to charge transfer and substantial buckling of the top silver layer and of the adsorbates. Upon mixing acceptor and donor molecules, strong hybridization occurs between the two different molecules leading to the emergence of a common unoccupied molecular orbital located at both the donor and acceptor molecules. The donor acceptor blend studied here is, therefore, a compelling candidate for organic electronics based on self‐assembled charge‐transfer complexes.