bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concurrent Resource Allocation (CRA): A Heuristic for Multi-Project Scheduling with Resource Constraints in Concurrent Engineering
Authors: Kara S. , Kayis B. , Kaebernick H. 
Published: March 2007

Concurrent Engineering (CE) has gained immense popularity around the world as a means of accelerating product develop ment, reducing cost, and increasing quality. CE achieves this by overlapping tasks and executing them in parallel. Different and inde pendent surveys conclude that significant benefits can be achieved as a result of implementing CE. However, CE radically affects the way projects are managed due to the complexities and uncertainties caused by executing tasks with incomplete information. This re quires careful planning and organization prior to implementing CE projects, otherwise delays in project completion and deterioration in project performance may occur due to the uncertainties in the process. Although the literature suggests that one of the essential ele ments for successfully implementing CE is careful and detailed project planning, very little attention is devoted to addressing this prob lem. This is due to the fact that CE is a relatively new concept and product development projects could be extremely complex [9]. In practice, project managers try to address uncertainty and resource allocation in a multi-project environment by using traditional project management tools and techniques. In this paper, a new multi-project scheduling heuristic is developed and used to address the problem of resource constraint scheduling in a multi-project CE environment. This proposed multi-project scheduling heuristic considers the unique characteristics of CE projects such as concurrency and dual-level project management structure. The superior performance and capability of the proposed multi-project scheduling heuristic are demonstrated by applying them to a case study gathered from an Australian manufacturing firm. In addition, the applicability of the available multi-project scheduling heuristics to the CE environment is also investigated. It is concluded that the new multi-project scheduling heuristic performs better than traditional ones in terms of minimizing project completion time and optimizing resource utilization.
Information Management for Concurrent Engineering: Research Issues
Authors: Prasad Biren , Morenc Roger S. , Rangan Ravi M. 
Published: March 2007

The development of products in large industrial organizations involves numerous engineers from different disciplines working on interdependent components Objectives are sometimes in conflict The need for overall coordination, consistency, control, and integrity of data, design ideas, and design rationale is critical The information generated by each designer must be viewed in the context of information generated by other designers, the enterpnse historical data, and the organization as a whole. The paper outlines major requirements facing concurrent engineering (CE) It focuses on the ability of collaborating designers to proceed independently, correlate interdependency, use existing information (data, knowledge, and processes), and negotiate conflicts arising from design inconsistencies To provide information-based support for such environments a concept of design schemata is introduced to support the concurrent, collaborative, and historical aspects of CE environments from an enterprise perspective. The need for a data dictionary that supports these schemata and its different dimensions is also recognized The dictionary provides conceptual centralization of design information relative to the enterprise. This includes data, as well as its definition (meta-data), and must allow the design process to evolve in a global enterprise perspective These discussions lead to a series of research issues that must be addressed by the CE research community.
Heat-of-Adsorption Solar Thermal Energy Storage
Authors: Ucar Manas , Pounder Bruce 
Published: March 2007

The storage of solar thermal energy has been a subject of extensive study for many years. Various storage concepts have been extensively investigated. However, little research has been done on energy storage in the heat-of- adsorption of chemical compounds. Zeolite is, perhaps, the only substance that has been studied for its heat-of- adsorption properties (1). A recent proposal utilizes the hygroscopic properties of sodium sulfide for thermal storage (2). Sodium sulfide has a storage capacity of 3600 kJ per kilogram. The system is economically desirable as sodium sulfide costs a mere $0.27 per kilogram (3). Experimental research has been continuing for a year on the feasibility of the system. The performance of the model has been reasonably close to the expected level. It is believed that further work can raise the storage temperatures to levels suitable for space heating and other low temperature ap plications. This system has two problems: 1) the salt has to be under vacuum, 2) the chemical odor in the vacuum pump exhaust. A new conceptual design has been developed that eliminates the problem of odor and the need for a vacuum pump.
Heat and Mass Transfer in Fibrous Insulations
Authors: Langlais C. , Klarsfeld S. 
Published: March 2007

This paper is a synthesis of the various research projects studied by our research laboratory over the period 1974 to 1982 on the general topic of moisture. The various points covered by these projects, concerning exclusively mineral fiber insulations, are: • water vapor fixation mechanisms • vapor-barrier • moisture effect on heat transfer As a result of this work, we are able to assess that: • glass fibrous insulations with currently used binders are not hygroscopic • the vapor-barrier may be omitted in numerous applications • the effect of moisture on the thermal resistance of fibrous insulations can be considered as negligible in most building applications.
Thermal Transmittance of Concrete Block Walls with Core Insulation
Authors: Van Geem Martha G. 
Published: March 2007

Thermal transmittance values (U-values) of concrete block walls, with and without core insulation, tested at three laboratories are summarized. Insulations were perlite, vermiculite, expanded polystyrene (EPS) beads, and EPS inserts. Measured U-values are compared to values calculated using the isothermal planes method. For empty core concrete block walls with known concrete thermal conduc tivity, measured U-values were within 10% of calculated values. However, for walls with core insulation, measured U-values differed by 0% to 40% from calculated values. Sensitivity of wall thermal transmittance to changes in block configuration, con crete thermal conductivity, and fill thermal conductivity is discussed.
The Thermal Resistance of Spray-Applied Fiber Insulations
Authors: Yarbrough D.W. , Graves R.S. , Mcelroy D.L. , Desjarlais A.O. , Tye R.P. 
Published: March 2007

The thermal resistances of four cellulosic and three mineral fiber spray-applied m- sulations have been determined using the flat Nichrome screen-heater apparatus de veloped at the Oak Ridge National Laboratory. Measurements were also made at Dynatech Scientific, Inc., on two of the same specimens of the cellulosic material and one similar specimen of the same mineral fiber product using conventional guarded hot plate and heat flow meter apparatuses. The experimental data obtained at ORNL were used to calculate R-values at 75°F from data obtained in the range 81 to 133 ° F The R-values obtained at Dynatech in cluded measurements at 75°F as well as measurements from 50 to 100°F for cellu losic insulations and 25 to 150°F for a mineral fiber insulation. The results from the two laboratories for the thermal resistance of identical specimens of spray-applied cellulose agreed to better than 1% while the agreement on similar specimens of a spray-applied mineral fiber insulation differed by less than 3%. The data discussed in this paper include spray-applied insulations that span the density range 1 to 8 lb/ft3 and the results show that material R -values for the spray- applied products can be predicted to within ± 10%, using correlations for the ap parent thermal conductivities of loose-fill insulation of the same type and density. They show further that existing plate and similar longitudinal heat flow methods are most appropriate for evaluating the performance of these types of materials.
Flame-Retarded, Rigid PUR Foams with a Low Thermal Conductivity
Authors: Wiedermann R.E. , Adam N. , Kaufung R. 
Published: March 2007

This paper examines and discusses various ways of reducing the initial thermal conductivity value of PUR foams and slowing down the rate at which it rises. The initial value for thermal conductivity is shown to depend basically on cell size, and not on the type of raw materials system. In order to obtain a low initial value, the cells of the foam must be as small as possible. In order to investigate the rate at which thermal conductivity increases-in other words the ageing phenomenon—both the pressure and the composition of gas in the cells were determined. Two factors are shown to be responsible for increasing ther mal conductivity: 1. Permeation of air 2. Reduced R11 concentration of the gas in the cells as a result of ad- or absorption to the cell structure During the investigation period of 12 months, however, there was virtually no measurable reduction in R11 concentration in the foam. It was found that different raw materials had a considerable effect on air permea tion in the cells. Foams containing the following components exhibit little air permeation: toluene diisocyanate, aromatic aminopolyethers, phosphoros and halogen-containing flame retardants. An attempt was made to calculate thermal con ductivity from the change in the composition of gas in the cells. The calculations were then compared with actual measurements. With our new foam we couldn't find a loss of chlorofluorocarbon in the ageing process.
The Effects of Water as a Partial Blowing Agent for Rigid PUR and PUR/PIR Foams
Authors: Cunningham A. , Rosbotham I.D. , Sparrow D.J. , Brown R.K. , Galbraith C.J. 
Published: March 2007

Trichlorofluoromethane, CFC-11, is the predominant blowing agent used for rigid PUR and PUR/PIR insulation foams. The low thermal conductivity of CFC-11 provides these products with excellent insulation properties. But, it is now known that future supplies of CFC-11 may be limited and possibly eliminated as a consequence of international regulation. New, hydro-chloro-fluorocarbons (HCFCs) are under development and evaluation, with HCFC-141b and HCFC-123 emerging as the front runners to replace CFC-11. However, neither product is ex pected to be commercially available for several years. In the meantime, it is expected that regulation, in combmation with industry growth, will cause a real shortage of CFC blowing agent available for foam blowing. Water blowing of polyurethane foams has been used to a limited extent for a num ber of applications. Therefore, it was concluded that increasing the level of water blowing in PUR and PUR/PIR foams offered the most promising short term solution to extending future supplies of CFC-11. This paper discusses the use of water blow ing for a number of rigid foam applications including appliances and lamination boardstock. Information obtained from both laboratory and commercial production experience is presented. It is shown how careful optimization of all formulating ele ments involved can, in some cases, result in no loss in the foam insulation efficiency even with up to 40% reduction of CFC-11 usage.
An Evaluation of the Dow Thermal Performance Prediction Model for a Database of XEPS/CFC-12 Aged Resistivity and Physical Properties
Authors: Booth J. Richard 
Published: March 2007

For a number of years, The Dow Chemical Company has been using a semi-empirical model for predicting long-term insulation performance for the quality assurance process of STYROFOAM* Brand Insulation Board. The predictive capability of this model will be compared against aged samples. These results are selected from a database of resistivity measured on extruded polystyrene boards manufactured with CFC-12 as the captive blowing agent In addition to the resistivity, other physical properties that are typically used for product specification and quality assurance are included in the database The key features, input data, computer hardware requirements and limitations of this performance model are described in relation to the input data range and addi tional data (e.g., other than foam properties) that are required to run the model. The predictive performance was demonstrated for two stages of the aging process (the air influx and blowing agent emission) for samples varying in thickness from 1 to 6 inches. The overall relative standard deviation from the prediction-measurement regression was 2.5 percent, while thermal resistivity varied from 44.4 to 30.5 m °K/W (6.4 to 4 4 ft2 hr °F/Btu in)
The Acceleration of Foam Aging by Thin-Slicing: Some Interpretations and Limitations
Authors: Bhattacharjee D. , Irwin P.W. , Booth J.R. , Grimes J.T. 
Published: March 2007

Thin-slice accelerated aging methodologies have not been ag gressively pursued because of concerns about the reliability and applicability of the results. The use of gases such as helium, nitrogen and carbon dioxide, which diffuse rapidly and are only sparingly soluble in the polymer, may be used to obtain a diffu sion measurement in the foam matrix. These diffusion measurements provide a basis for examining the reliability of the scaling technique for more soluble blowing agents. Results of numerical solutions of the diffusion equation suggest that there may be a thickness limit for thin-slicing, depending on cell size. The existence of this limit may be evaluated by examining the effects of slice thickness on the effective diffusion coefficients of the pure sparingly soluble gases in foam samples. In this investigation, diffusion will be monitored by two different measurements: weight change (gain or loss) and thermal conductivity increase during air uptake and blowing agent loss. The effective diffusion coefficients from both measurements will be compared to demonstrate a consistent diffusion mechanism. Both polyurethane (PU) and polyurethane modified polyisocyanurate (PUIR) foams will be used for this demonstration. The goal is to show that thin-slice methodology balances the need for precise measurements with the desire for a significant reduction in testing time. The desire for a significant reduction in testing times is particularly important as environmentally damaging blowing agents (chlorofluorocarbons) are being replaced by less environmentally damaging blowing agents (such as the hydrochlorofluoro carbons HCFC-141b, HCFC-22 and HCFC-123). The effective diffusion coeffi cients of slices as thin as 0.0013 m agree with those up to 0.025 m thick, based on ad justed thermal conductivities for PUIR foams blown with CFC-11.
Discussion of Heat Flow Meter Apparatus Calibration and Traceability Issues for Thermal Conductivity Measurements
Authors: Scott J.A. , Bell R.W. 
Published: March 2007

During a period where both North American and International product markets are opening, the issue of calibration traceability has become a sig mficant issue in the calibration of heat flow meters [1,2] used in thermal conductivity measurements on insulation materials. This paper will discuss the approach of the Production Support Services Laboratory of Owens Corning/Fiberglas Canada Inc. in addressing traceability to U.S., Canadian and International standards orgamza tions. As a wide range of insulation products with varying thickness, density and R- values are tested in this laboratory, the calibration requirements may become quite elaborate. Included in this paper will be a techmcal discussion of the calibration stud ies and their findings performed on two different designs of heat flow meter appara tus. The calibration discussion is limited to a narrow temperature range typically used in the evaluation of insulation products to standard specifications.
Parental, Peer, Teacher and Sporting Hero Influence on the Goal Orientations of Children in Physical Education
Authors: Carr Sam , Weigand Daniel A. 
Published: March 2007

The purpose of this study was to examine the relationship between goal orientations and perceptions of the motivational climate emphasized by parents, peers, teachers and sporting heroes for children in physical education (PE). Additionally, gender differences in goal orientations and perceptions of the motivational climate were examined. A total of 266 male and female secondary school PE pupils from the United Kingdom completed a survey assessing personal goal orientations for PE and perceptions of the motivational climateemphasized by parents, peers, teachers and sporting heroes. Results indicated that goal orientations were related to these perceptions. Specifically,task orientation was related to perceptions of a learning-oriented climate from parents, peers and teachers and to perceptions of a mastery orientationinsporting heroes. In contrast, an ego orientation was related to perceptions of a comparison climate from parents, peers and teachers, and to perceptions of an ego orientation in sporting heroes. Results are discussed in terms of the implications that the influence of significant others might have for intervention efforts designed to enhance the quality of youngsters’ motivational development in PE.
Playing With Things
Authors: Dant Tim 
Published: March 2007

The sociology of leisure traditionally focuses on human relations, treating any material objects used as marginal to the activity. This article argues that some recreational activity is realized through interaction with material objects and uses the example of windsurfing to show how. Three approaches to understanding the sociological features of the human-object interaction are considered. The first looks at playing as a distinctive type of social activity; how playing with a windsurfer involves 'ilinx' type play (Caillois, 1961) and how it may lead to 'play-excitement' (Elias and Dunning, 1986). The second argues that consumption, through the exchange of value and signs in a variety of discourses, socially locates the play activity of wind surfing. The third approach looks at the way that the user interacts (Mead, 1962; 1980) with the objects of the windsurfer to engage in play. These three approaches together show that playing with things like wind surfers provides a particular type of emotional outlet, situates the sailor in particular social contexts and shapes particular lines of action, including imaginative and discursive action.
Richard Hoggart's grandmother's ironing
Authors: Gibson Mark 
Published: March 2007

The paper reviews a moment within early British cultural studies as a way of asking whether the concept of power is as necessary to the field as is generally believed. It attempts to establish that the concept was not a central one - and was in fact specifically avoided - in the intellectual and political project suggested by the 'founding' work of Richard Hoggart and Raymond Williams. It was introduced as part of a deliberate intervention against that project which first appeared in criticisms of Williams by E.P. Thompson and later taken up in the systematic adoption of 'theory'. The opening of a possibility that cultural studies may have an intellectual and political credibility without being 'about' power is used to reflect on some of the problems now facing the field at the moment of its internationalization. It is sug gested that a number of these problems might be addressed more openly and directly if the use of the concept of power is understood as contingent rather than fundamental.
Herald of hybridity
Authors: Schoene Berthold 
Published: March 2007

The paper reads Hanif Kureishi's The Buddha of Suburbia as a paradigmatic example of post-imperial ethno-English writing. Kureishi's novel propagates an emancipation of ethnic difference from both the discriminatory stereotyping institutionalized by current multiculturalist discourse as well as the postcolonial migrant subject's propensity for self-oppressive role-play and anglophile mimicry, most notably problematized in Salman Rushdie's intercultural experiment of The Satanic Verses. Kureishi's novel breathes life into the utopian envisionings of several prominent cultural theorists of the 1990s. The paper refers to Homi K. Bhabha's location of culture in the deconstructive Third Space of a cultural in-between as well as Judith Butler's argument on sexuality's subversion of epistemological closure. It also discusses Terry Eagleton's call for a radical redefinition of the relations between cultural homo- and heterogeneity and Eve Kosofsky Sedgwick's axiomatic concerning a proprioceptive liberation of the individual subject from the ideological straitjackets of hegemonic perception.
Orientation in Immigrant Narratives: The Role of Ethnicity in the Identification of Characters
Authors: DE FINA ANNA 
Published: March 2007

Every year, thousands of undocumented Mexican workers enter the United States. Their presence, together with the settlement of undocumented and legal immigrants from many other countries, constitutes the source of one of the most persistent ideological conflicts in American history: the conflict over immigrants' rights. Official discourses in many cases identify being Hispanic with poor performance at school, drug abuse, poverty and violence. However, aside from mainstream images of who immigrants are, little research has been done on the identity that immigrants themselves build and project, and on the processes that affect the formation of such identity.In this article I investigate identity through discourse analysis, looking specifically at linguistic strategies used by a group of undocumented Mexican immigrants to identify characters in storytelling. I argue that immigrants use ethnic identity as a central identification category for self and others in their stories, showing that ethnic mentions are widespread in story orientations, and that they exhibit different degrees and types of relevance depending on their relationship with the interactional context and/or the story world. Ethnic mentions are used in stories to affirm certain characteristics of one's own identity and of the identity of others via the presentation and evaluation of behaviors. In argumentative stories disputable behaviors are openly attributed to out groups, and so these stories help speakers to build images of who they are and how they stand in relation to others. In stories of personal experience, the connections between identities and behaviors are implicit, but they still respond to socially established expectations. Thus, individual stories also contribute to build those expectations about how belonging to certain ethnic groups may affect action in particular domains of life.The pervasiveness of ethnic identification in immigrant stories cannot be understood without resorting to wider social processes that frame the immigration experience of undocumented Mexican workers. In this case, I stress the importance of the pressure that the ideology of race and ethnicity, enacted through public discourse at all levels, exerts on every individual in American society.
Cutting of Airbag Materials
Authors: Shurling Roy 
Published: March 2007

There are currently two principle material types which are used in the manufacture of airbags. They are uncoated nylon (polyamide 66) and coated nylon. Two types of commonly used coatings are Silicone and Neoprene. In general, coated materials are used for driver's side airbags and side impact bags, while passenger side airbags are made from uncoated nylon materials. Different cutting methods are needed for the two different classifications of mate rials. Coated nylon can be cut with traditional mechanical tools such as dies or reci procating knife cutters, due principally to the fact that the coating prevents fraying. On the other hand, uncoated nylon must be cut with a hot tool, such as a laser to pre vent fraying; fraying could compromise the airbag integrity during deployment.