bluuebunny/crossref_metadata_2025 huggingface dataset:
Mathematical modeling of air duct heater using the finite difference method
Authors: Sarafraz M. , Peyghambarzadeh S. , Marahel A.
Published: January 2012

Mathematical modeling of air duct heater using the finite difference method

In this research, mathematical modeling of a duct heater has been performed using energy conservation law, Stefan-Boltzman law in thermal radiation, Fourier's law in conduction heat transfer, and Newton's law of cooling in convection heat transfer. The duct was divided to some elements with equal length. Each element has been studied separately and air physical properties in each element have been used based on its temperature. The derived equations have been solved using the finite difference method and consequently air temperature, internal and external temperatures of the wall, internal and external convection heat transfer coefficients, and the quantity of heat transferred have been calculated in each element and effects of the variation of heat transfer parameters have been surveyed. The results of modelling presented in this paper can be used for the design and optimization of heat exchangers.
Activity of monolithic Pd/Al2O3 catalysts in the combustion of mine ventilation air methane
Authors: Kucharczyk Barbara
Published: January 2012

Activity of monolithic Pd/Al2O3 catalysts in the combustion of mine ventilation air methane

The activity of Pd/Al2O3 catalysts increases when Pd content is increased from 1% to 2%. Among these catalysts, 2%Pd/Al2O3 shows the highest methane combustion activity. In a reduced form, the catalyst displays a higher activity than in the oxidized form. 24-hour ageing at 600°C to 800°C lowers the catalytic activity of 2%Pd/Al2O3 due to Pd crystallite sintering. After 110-hour oxidation of 1% methane in air over 2%Pd/Al2O3, conversion decreases from 100% to 88%. Upon reduction with hydrogen (performed after 24-hour ageing at 700°C and 110-hour methane oxidation), the 2%Pd/Al2O3 catalyst regains its initial activity. The high activity of Pd catalysts renders them suitable for methane removal from coal mine ventilation air at high gas flow velocities and temperatures lower than 600°C.
Influence of reduction time of copper based catalysts: Cu/Al2O3 and CuCr2O4 on hydrogenolysis of glycerol
Authors: Wołosiak-Hnat Agnieszka , Milchert Eugeniusz , Lewandowski Grzegorz , Grzmil Barbara
Published: January 2012

Influence of reduction time of copper based catalysts: Cu/Al2O3 and CuCr2O4 on hydrogenolysis of glycerol

High activity of copper based catalysts for C-O bond hydro-dehydrogenation and their poor activity for C-C bond cleavage1 have prompted an attempt to apply such catalysts in the hydrogenolysis of glycerol to 1,2- and 1,3-propanediol. In the present study the influence of hydrogen reduction time of the Cu/Al2O3 and CuCr2O4 copper catalysts on glycerol conversion and selectivity of transformation to propanediols and by-products was studied. At first a general comparison was made between the commercial catalysts and those prepared by the co-precipitation method. As better results were obtained in the presence of catalysts prepared by co-precipitation, they were selected for further detailed studies of the influence of reduction time. For both prepared catalysts Cu/Al2O3 and CuCr2O4 the reduction time of 8 h was optimal. In the presence of Cu/Al2O3 catalyst the conversion of glycerol was 59.0%, selectivity of transformation to 1,2-propanediol 77.4% and selectivity to 1,3-propanediol 1.9%. In the presence of CuCr2O4 the glycerol conversion was 30.3% and selectivity to 1,2-propanediol 67.3%.
Comments on "3-aminopropyltriethoxysilane functionalized nanoscale zero-valent iron for the removal of dyes from aqueous solution"
Authors: Ho Yuh-Shan
Published: January 2012

Comments on "3-aminopropyltriethoxysilane functionalized nanoscale zero-valent iron for the removal of dyes from aqueous solution"
Palaeoslopes of Weichselian sand-bed braided rivers in the Toruń Basin (Poland): results of a palaeohydraulic analysis
Authors: Weckwerth Piotr
Published: January 2012

Palaeoslopes of Weichselian sand-bed braided rivers in the Toruń Basin (Poland): results of a palaeohydraulic analysis

Palaeoslopes of Weichselian sand-bed braided rivers have been reconstructed for two stages of fluvial development in the Toruń Basin. (1) The palaeoslope of the ‘fossil’ fluvial succession (buried under Weichselian tills) was calculated on the basis of the median grain size and the Shields parameter. The hydraulic gradient thus found is comparable with the hydraulic gradient of the present-day river. (2) The second developmental stage of the Toruń Basin (as a apart of the Noteć-Warta ice-marginal valley) took place after deglaciation. The slopes of river terraces are a few times lower than those calculated on the basis of the Shields parameter. The palaeoslope of the then river was estimated on the basis of a constant interdependency between the braidplain width, the channel geometry and the grain size. The river gradient that was thus calculated is similar to the measured terrace slope. Palaeoslope estimates in valleys similar to those in the Toruń Basin should consider the width of the braidplain.
Reply to Comments to X. Li and Y. M. Wang (2011) Comparisons of geoid models over Alaska computed with different Stokes' kernel modifications, JGS 1(2): 136-142 by L. E. Sjöberg
Authors: Wang Y.
Published: January 2012

Reply to Comments to X. Li and Y. M. Wang (2011) Comparisons of geoid models over Alaska computed with different Stokes' kernel modifications, JGS 1(2): 136-142 by L. E. Sjöberg

The authors thank professor Sjöberg for having interest in our paper. The main goal of the paper is to test kernel modification methods used in geoid computations. Our tests found that Vanicek/Kleusberg's and Featherstone's methods fit the GPS/leveling data the best in the relative sense at various cap sizes. At the same time, we also pointed out that their methods are unstable and the mean values change from dm to meters by just changing the cap size. By contrast, the modification of the Wong and Gore type (including the spectral combination, method of Heck and Grüninger) is stable and insensitive to the truncation degree and cap size. This feature is especially useful when we know the accuracy of the gravity field at different frequency bands. For instance, it is advisable to truncate Stokes' kernel at a degree to which the satellite model is believed to be more accurate than surface data. The method of the Wong and Goretype does this job quite well. In contrast, the low degrees of Stokes' kernel are modified by Molodensky's coefficients tn in Vanicek/Kleusberg's and Featherstone's methods (cf. Eq. (6) in Li and Wang (2011)). It implies that the low degree gravity field of the reference model will be altered by less accurate surface data in the final geoid. This is also the cause of the larger variation in mean values of the geoid.
Calibration of Highway Safety Manual Predictive Models for Oregon State Highways
Authors: Xie Fei , Gladhill Kristie , Dixon Karen K. , Monsere Christopher M.
Published: January 2012

The recently released Highway Safety Manual (HSM) published by AASHTO provides a comprehensive set of tools for evaluating and identifying opportunities to improve safety for highway facilities. Included in the HSM is a quantitative method for predicting crashes on the basis of recently developed scientific approaches. These predictive methods currently exist for three facility types: rural two-lane roads; rural multilane highways; and urban and suburban arterial highways. To enhance precision, each HSM predictive method should be calibrated for location conditions. This paper demonstrates the HSM calibration procedure for total crashes in Oregon. The research identified three critical data collection limitations on information about pedestrian volumes, minor road traffic volumes at rural locations, and minimum sample size for underrepresented crash locations. Most of the calibration factors for Oregon were determined to be considerably lower than the expected value of approximately 1, and this observation was attributed to Oregon crash reporting thresholds and procedures. The paper includes an evaluation of crash severity distribution methods and an assessment of the significance of collision type distributions on the overall predicted crashes.
Investigation of Effects of Underreporting Crash Data on Three Commonly Used Traffic Crash Severity Models
Authors: Ye Fan , Lord Dominique
Published: January 2012

Although much work has been devoted to developing crash severity models to predict the probabilities of crashes for different severity levels, few studies have considered the underreporting issue in the modeling process. Inferences about a population of interest are biased if crash data are treated as a random sample from the population without consideration of the different unreported rates for each crash severity level. The primary objective of this study was to examine the effects of underreporting for three commonly used traffic crash severity models: multinomial logit (MNL), ordered probit (OP), and mixed logit (ML) models. The objective was accomplished with a Monte Carlo approach that used simulated and observed crash data. The results showed that, to minimize the bias and reduce the variability of a model, fatal crashes should be set as the baseline severity for the MNL and ML models, while for the OP models, the rank for the crash severity should be set from fatal to property damage only in a descending order. None of the three models was immune to this underreporting issue. When full or partial information about the unreported rates for each severity level was known, treatment of the crash data as outcome-based samples in model estimation (through the weighted exogenous sample maximum likelihood estimator) dramatically improved the estimation for all three models as compared with the results produced from the maximum likelihood estimator.
Agent-Based Stochastic Modeling of Driver Decision at Onset of Yellow Light at Signalized Intersections
Authors: Amer Ahmed , Rakha Hesham , El-Shawarby Ihab
Published: January 2012

This paper introduces two logistic statistical models for the driver stop–run decision at the onset of yellow at signalized intersections to capture the stochastic nature of the driver stop–run decision. One model is a classical frequentist model, whereas the other uses a Bayesian statistics approach. The Bayesian model parameters were calibrated by using the Markov Chain Monte Carlo slice procedure implemented within the MATLAB software. Both models were developed with 3,328 stop–run records, which were collected in a field experiment on the Virginia Smart Road, a limited-access highway between Blacksburg and Interstate 81 in Montgomery County, Virginia. The variables included in each model were driver gender, age, time to intersection, yellow time, approaching speed, and speed limit. Both models were shown to be consistent. For the Bayesian model application, two procedures were illustrated: cascaded regression and Cholesky decomposition. Both procedures produced replications consistent with the Bayesian model realizations, while these procedures captured the parameter correlations without the need to store the set of parameter realizations. The Bayesian model produced valid and transferable behavior by replicating multiple experimental results. The proposed Bayesian approach is ideal for modeling multiagent systems in which each agent has its own unique set of parameters.
Automated Detection of Spatial Traffic Violations through use of Video Sensors
Authors: Ismail Karim , Sayed Tarek , Zaki Mohamed H. , Alrukaibi Fahad
Published: January 2012

It is plausible that road use behavior that leads to traffic violations can be a contributing factor to the failure mechanism that prompts a collision. The detection and the understanding of traffic violations, therefore, can be key components of a sound safety diagnosis. Recent advances in computer vision techniques have enabled the conduct of automated and large-scale analyses of various approaches to safety diagnoses, including traffic conflicts and violation analysis. This paper proposes and compares two approaches to detect vehicular spatial violations. The approaches are (a) k-means clustering and (b) pattern matching with use of the longest common subsequence (LCSS) similarity measure. The purpose of this study was to learn what constituted normal movement patterns and to interpret any discrepancy between these patterns and observed tracks as an indication of a traffic violation. Each of the approaches was applied to detect U-turn violations on an urban intersection in Kuwait City, Kuwait. Violation detection on the basis of LCSS generally was superior to detection with piecewise k-means clustering, especially when low false detection rates were desirable. This expected differential was the result of the performance of LCSS matching on observed road user positions, and not on an approximated model.
Use of Light Detection and Ranging Data to Identify and Quantify Intersection Obstruction and Its Severity
Authors: Tsai Yichang , Yang Qiang , Wu Yiching
Published: January 2012

The identification of obstructions at intersections is crucial for roadway safety improvement. Field measurements used to identify intersection obstructions, however, are labor intensive, costly, and dangerous. This study explores the feasibility of identifying obstructions at intersections by using light detection and ranging (LiDAR) data already available for flood analysis. Because it can model three-dimensional objects, emerging LiDAR technology provides a good way to identify intersection obstructions. The objective of this study was to propose a methodology that could identify intersection obstructions by using LiDAR technology, three-dimensional terrain modeling, a plane-of-sight, and geographic information system spatial analysis. The methodology that was sought was also one that could quantify the severity levels of intersection obstructions and, potentially, be used to prioritize improvements for network-level safety. With the use of LiDAR data already available from Savannah, Georgia, experimental tests were conducted to identify obstructions at intersections. The intersection obstructions, identified with the proposed methodology, were compared with those obtained with the use of the 100-ft (30.5-m) line-of-sight (LOS) method. Results showed that the proposed method correctly identified 92% of intersection obstructions, compared with 64% identified by the LOS method. The severity levels of intersection sight distance obstructions also were quantified. Results showed that the proposed methodology provided a feasible platform and method for transportation agencies to use emerging LiDAR technology to identify intersection obstructions.
Workplace Simulator for Geometric Design of Rural Roads
Authors: Kühn Wolfgang , Volker Hendrik , Kubik Ronny
Published: January 2012

The planning and design process for rural roads in Germany takes place iteratively within various design stages, each followed by a subsequent approval procedure. Design engineers do not, however, have adequate aids for the technical aspects of design work (i.e., search for route, comparison of options, safety checks) apart from general rules and regulations. In Germany, a new kind of design methodology is being developed as part of a research project in which a new model concept (three-dimensional route search) is being used. Fifth-degree Bézier curves are used for the three-dimensional route, and the curves enable the curvature features of a combined curve (clothoid, circular arc, and clothoid) to be generated in the sections that require a transition curve. Three-dimensional straights can also be represented with this mathematical approach. Once the three-dimensional route has been broken down into the individual design levels, two-stage safety checks take place according to geometrical criteria (set guidelines) and the expected driving behavior (simulation). The design engineer is supported in the interactive planning and checking process by various visualization techniques (e.g., two- and three-dimensional display, simulation along the virtual driving area). The workplace simulator that has been developed combines the design methodology and hardware and software components and therefore uses the all-around process of designing, checking, driving, and assessing in a practical manner.
Method for Evaluation of Sustainable Transportation
Authors: Samberg Stuart , Bassok Alon , Holman Shawna
Published: January 2012

A crucial element of sustainability is the optimization of system efficiency by the maximization of existing resources and the limitation of the necessity of infrastructure expansion. Although the Leadership in Energy and Environmental Design certification is an internationally recognized standard for determining sustainable architecture, no officially accepted method exists for evaluating sustainable transportation. The development of a performance evaluation method for sustainable transportation is necessary, with a focus on multimodal mobility rather than on automobility. It is crucial that current transportation projects not preclude the provision of multimodal mobility options in the future. This paper reviews the literature on operational and proposed evaluation strategies for transportation projects and proposes a sustainable transportation evaluation method. The sustainable transportation evaluation method builds on the observed beneficial qualities of the existing evaluation systems and attempts to address their shortcomings. Implementation of the sustainable transportation evaluation method relies on established multicriterion techniques that allow for quantitative and qualitative evaluation of the sustainability of transportation projects during the planning, design, and construction phases. The evaluation method proposed can augment traditional environmental analysis performed for transportation project selection. The method is designed to be flexible so that it can be easily implemented by a wide range of stakeholders who are considering diverse issues.
Framework for Sustainability Assessment by Transportation Agencies
Authors: Ramani Tara Lakshmi , Zietsman Josias , Gudmundsson Henrik , Hall Ralph P. , Marsden Greg
Published: January 2012

The application of the concept of sustainability by transportation agencies is often limited by agencies’ understanding of what sustainability means and how it can be integrated into the regular functions of the agencies. This paper presents a flexible approach and framework that can equip transportation agencies with the tools required to understand what sustainability means and incorporate sustainability into the organizational culture. This approach and method can also help agencies lay the groundwork for the use of performance measures so the agencies can progress toward sustainability goals and outcomes. The framework development process was an extension of findings from literature review, case studies, and interviews conducted as part of ongoing research under the NCHRP project Sustainability Performance Measures for State Departments of Transportation and Other Transportation Agencies. The proposed framework can be applied or adapted for use in a range of transportation agencies, including state departments of transportation and metropolitan planning organizations. A key feature of this framework is that it moves away from the traditional sustainable transportation perspective and instead promotes the consideration of transportation from a holistic sustainable development perspective. The framework defines broadly applicable transportation goals that can be broken down into a menu of objectives and performance measures to cover various transportation contexts. The framework is also designed to direct an agency's strategic planning toward the practical implementation of sustainability through performance measurement.
Quantifying the Economic Domain of Transportation Sustainability
Authors: Zheng Jason , Atkinson-Palombo Carol , McCahill Chris , O'Hara Ryan , Garrick Norman W.
Published: January 2012

The lens of sustainability refocuses the perception of transportation and allows a look beyond its accustomed role of providing vehicular mobility to the broader impacts of transportation on the environment, society, and the economy. As the understanding of transportation's function evolves beyond throughput and capacity, sustainability can be used as an organizing principle for transportation planning to promote livable communities. To fully understand and integrate the ideas of sustainability with transportation, the proper metrics and performance measures need to be developed and adopted. This study demonstrated how the theoretical concepts and definitions of transportation sustainability could be transformed into a practical metric for assessing the performance of the U.S. transportation system in terms of sustainability. The study focused on characterizing and measuring the economic aspect of sustainability in relation to transportation. The analysis was carried out for surface transportation at the statewide level and took into consideration the degree of urbanization of states. The final results described the relationship between urbanity, mode share, and the economic aspects of transportation sustainability. On the basis of this assessment, the best-performing states in terms of the economic aspects of transportation sustainability were more urban and had lower automobile mode shares.
Backcasting for Sustainable Transportation Planning
Authors: Barrella Elise , Amekudzi Adjo A.
Published: January 2012

Transportation problems are often sustainability problems and as such are complex, long-reaching, and difficult to address through incremental policies. Planning for these problems requires analyzing future conditions of the transportation system and the systems with which it interacts. Traditional futures studies using the forecasting method do not deal adequately with the uncertainty inherent in long-term studies of transportation problems. This paper reviews recent innovations in futures studies and their applications to planning studies for transportation system sustainability. The new methods, including scenario planning, backcasting (determining policy to meet future end point), and strategic sustainability assessment, involve both qualitative assessment and scientific models to create and analyze future states. In particular, the paper focuses on backcasting as an alternative to forecasting for scenario building and provides examples of how the method has been applied in the transportation sector. The review suggests that backcasting is a better option for analyzing transportation sustainability problems because it is an action-oriented approach focused on creating desirable future images and developing effective policies for achieving them.
Sustainable Road Transport in the European Union
Authors: Shen Yongjun , Ruan Da , Hermans Elke , Brijs Tom , Wets Geert , Vanhoof Koen
Published: January 2012

Road transport is vital to economic development, trade, and social integration. However, such transport is also responsible for the majority of negative impacts on the environment and society. To achieve sustainable development, a country increasingly needs to assess its undesirable costs to determine its road transport policy. In this study, total energy consumption, greenhouse gas emissions, and the number of fatalities in the European road transport system were selected to represent the level of sustainable development in each member–state of the European Union. With data from 1995 to 2007, the extent to which the 27 European Union countries improved their productivity on sustainable road transport was evaluated on the basis of data envelopment analysis and the Malmquist productivity index. The Malmquist productivity index measures productivity change over time and can be further broken down into two components: change in efficiency and technical change. The results showed considerable progress toward sustainable road transport in Europe during this period. The breakdown into the two components further revealed that the bulk of the improvement was attained through the adoption of productivity-enhancing new technologies throughout the road transport sector rather than through the lessening of the difference between relatively inefficient countries and efficient ones. In addition, the growth in both aspects slowed in 2007; this aspect implied that the momentum of further improvement was in danger of being lost and that new impetus was needed.
Framework for Assessing Indicators of Environmental Impacts in the Transport Sector
Authors: Joumard Robert , Gudmundsson Henrik , Folkeson Lennart
Published: January 2012

The following questions were addressed in this study: How can environmental impacts of transport be identified? How can the impacts be represented by operational indicators? How can several indicators be considered jointly? How can indicators be used in planning and decision making? First, a definition of the phrase “indicator of environmental impacts in the transport sector” was derived. The concept of a chain of causality between a source and a final target was developed as a common reference for indicators and their assessment. Criteria and methods for the assessment and selection of indicators were derived in terms of measurement, monitoring, and management. Finally, examples of the application of the criteria for individual indicators of seven chains of causality and for selected aggregated indicators were developed and are presented in this paper.
Introduction of Electric Vehicles to Ireland
Authors: Brady John , O'Mahony Margaret
Published: January 2012

The objective of this study was to undertake a social cost–benefit analysis of the proposed deployment of 230,000 electric vehicles in Ireland by 2020. The study analyzed the socioeconomic costs and benefits of this policy by comparing the environmental benefits, expressed in monetary values, with the associated reduction in tax revenues and the cost of the government's electric vehicle grant scheme. The study found that the 10% penetration of annual sales by electric vehicles by 2020 would result in a monetary loss of approximately €324 million (US$ 457 million) for the government (0.5% to 1% of total tax revenue expressed at 2009 levels). The primary reason for this shortfall would be a loss in all sources of tax revenue as a result of the electric vehicle penetration rates required to achieve an appreciable reduction in greenhouse gas emissions.
The Worst Are Always the Worst
Authors: Qu Tongbin Teresa , Lomax Timothy J.
Published: January 2012

The concept of a congestion threshold is embedded in the definition of “congestion.” Two basic approaches exist in current practice for setting the congestion threshold. One common approach uses the free-flow or unimpeded conditions. Another approach uses a variety of targets or acceptable conditions. The limited research conducted on the congestion threshold issue has focused on operational problems or policy debates, but there has been relatively little investigation of the effect of the congestion threshold on decision making for transportation investment and resource allocation. This research investigated the differences that might be seen in the worst freeway rankings for several threshold choices by using detailed freeway data from seven metropolitan areas. Specifically, this research examined the ranking values of two congestion measures under a variety of real-world travel time distributions. The congestion performance measures of delay per mile and travel time index were evaluated; these measures included different aspects of the congestion problem. The research results showed that the rankings of freeway congestion levels held steady across the set of congestion thresholds ranging from 60 to 30 mph. The same sections were ranked as very congested for all possible threshold values. From an investment point of view, therefore, the research found that congestion threshold speed should not be a concern for funding allocation. The data analysis found that the amount of delay was decreased by 10% for every 5 mph decrease in the congestion threshold speed. This decrease confirmed that thresholds were not irrelevant for all analyses.
Beyond the Inner City
Authors: Hu Lingqian , Giuliano Genevieve
Published: January 2012

In this study the job accessibility of low-income job seekers was compared with that of the affluent majority in a polycentric urban structure. Kain's spatial mismatch hypothesis was extended not only to examine where and why low-income job seekers have lower job accessibility than high-income job seekers but also to compare changes from 1990 to 2000 in the Los Angeles, California, metropolitan area. The job accessibility measure applied in this research captured travel impedance and both job supply and demand. The results suggested that spatial mismatch still existed and that it continued to increase over time. However, the spatial pattern of mismatch had changed. Low-income job seekers were more disadvantaged in the inner-ring suburbs, mainly because of the lag in the residential suburbanization of low-income job seekers. This research contributed to the understanding of the extent and consequences of urban spatial transformation and suggested that social equity problems be addressed from a broader spatial perspective.
Accessibility-Based Factors of Travel Odds
Authors: Case Robert B.
Published: January 2012

Given the widespread use of automobiles for personal transportation in the United States with the associated dispersion of land uses and limited scope of public transportation, the travel of nondrivers is limited in many American municipalities. Although some governments have tried to improve nondriver accessibility by coordinating land use and transportation— specifically improving the proximity of bus stops, activity locations, and residences favored by nondrivers—no existing performance measurement technique for these government efforts toward nondrivers is known. By applying a model produced in an earlier effort based on surveyed outcomes to measure the impact of accessibility on the odds of nondrivers’ leaving their home on a given day, that is, travel odds, this paper presents a technique for measuring the performance of government in coordinating transportation and land use to improve nondriver accessibility. To improve low performance, the government may further apply this technique to visually identify the best neighborhoods on which to focus improvement efforts. The government can improve nondriver accessibility in these promising neighborhoods—and thereby efficiently improve nondriver accessibility in its jurisdiction—by using its zoning and budgetary powers to modify land use and expand bus service to position together activity locations, bus stops, and residences favored by nondrivers.
Spatial Panel Econometric Analysis of Economic Impacts of Bypasses
Authors: Mills Joshua B. , Fricker Jon D.
Published: January 2012

This study took a regional approach to the economic impacts of bypasses. The study considered not only how the bypassed communities were affected but also how areas surrounding these communities were affected and whether these impacts differed. Zip code–level data were collected for three states in the Midwest: Illinois, Indiana, and Ohio. This area contained more than 60 bypasses of variably sized communities. The study focused on the manufacturing sector, which made up a major portion of the economy in this region. With a synthesis of economic theory and transportation systems analysis, spatial panel econometric models were estimated to determine whether these communities were significantly affected with respect to employment, establishment, and payroll levels. The findings of this study provided insight into the magnitude of the impacts of bypasses as well as how these impacts varied over space.
Relative Pesticide and Exposure Route Contribution to Aggregate and Cumulative Dose in Young Farmworker Children
Authors: Beamer Paloma I. , Canales Robert A. , Ferguson Alesia C. , Leckie James O. , Bradman Asa
Published: January 2012

The Child-Specific Aggregate Cumulative Human Exposure and Dose (CACHED) framework integrates micro-level activity time series with mechanistic exposure equations, environmental concentration distributions, and physiologically-based pharmacokinetic components to estimate exposure for multiple routes and chemicals. CACHED was utilized to quantify cumulative and aggregate exposure and dose estimates for a population of young farmworker children and to evaluate the model for chlorpyrifos and diazinon. Micro-activities of farmworker children collected concurrently with residential measurements of pesticides were used in the CACHED framework to simulate 115,000 exposure scenarios and quantify cumulative and aggregate exposure and dose estimates. Modeled metabolite urine concentrations were not statistically different than concentrations measured in the urine of children, indicating that CACHED can provide realistic biomarker estimates. Analysis of the relative contribution of exposure route and pesticide indicates that in general, chlorpyrifos non-dietary ingestion exposure accounts for the largest dose, confirming the importance of the micro-activity approach. The risk metrics computed from the 115,000 simulations, indicate that greater than 95% of these scenarios might pose a risk to children’s health from aggregate chlorpyrifos exposure. The variability observed in the route and pesticide contributions to urine biomarker levels demonstrate the importance of accounting for aggregate and cumulative exposure in establishing pesticide residue tolerances in food.
Implications of Trauma among Male and Female Offenders
Authors: Matheson Flora I.
Published: January 2012

Criminal behaviour is believed to arise from a multiplicity of factors, including unemployment and poverty [1,2], low self-control [3], psychological issues [4,5], early conduct problems [6], childhood physical and sexual abuse disorder [5], and social bonding in child- and adulthood [7]. Social-structural influences like family conflict/disruption, financial resources, child-parent and school/peer attachment and abuse and neglect in childhood have lasting impressions, leading to multiple problems including delinquency and later criminal activity, substance use/abuse, mental illness and poor self-rated health [8-12]. The consequences of such behaviour include financial losses, injury, and death that together have significant personal and societal costs. Society also bears the burden of incarcerating and rehabilitating offenders; a burden that is not trivial. Direct costs of imprisonment in Canada approach $3.5 billion annually; in the US the cost is substantially higher, approaching $74 billion [13]. [...]
Equilibrium constants and protonation site for N-methylbenzenesulfonamides
Authors: Moreira José A , Rosa da Costa Ana M , García-Río Luis , Pessêgo Márcia
Published: January 2012

The protonation equilibria of four substituted N-methylbenzenesulfonamides, X-MBS: X = 4-MeO (3a), 4-Me (3b), 4-Cl (3c) and 4-NO2 (3d), in aqueous sulfuric acid were studied at 25 °C by UV–vis spectroscopy. As expected, the values for the acidity constants are highly dependent on the electron-donor character of the substituent (the pKBH+ values are −3.5 ± 0.2, −4.2 ± 0.2, −5.2 ± 0.3 and −6.0 ± 0.3 for 3a, 3b, 3c and 3d, respectively). The solvation parameter m* is always higher than 0.5 and points to a decrease in the importance of solvation on the cation stabilization as the electron-donor character of the substituent increases. Hammett plots of the equilibrium constants showed a better correlation with the σ+ substituent parameter than with σ, which indicates that the initial protonation site is the oxygen atom of the sulfonyl group.
Valeurs universelles et relativisme culturel en recherche internationale: les contributions d'un principisme sensible aux contextes socioculturels
Authors: Massé Raymond
Published: January 2012

Résumé La grande majorité des organismes internationaux et nationaux de recherche s’accordent pour reconnaître aujourd’hui l’impératif d’encadrer la recherche internationale par des normes éthiques. Plusieurs comités d’éthique dans le champ de la santé s’efforcent alors de baliser l’acceptable et le justifiable dans les protocoles de recherche soumis à l’analyse. Leur recours à des principes éthiques ou des valeurs à portée universelle s’inscrit pourtant dans le contexte d’un discours critique musclé sur les limites d’une éthique normative fondée sur l’application de tels principes. Le présent article soutient que ces critiques sont souvent mal fondées, qu’elles concernent plus des usages abusifs et restrictifs qui dénaturent le principisme et qu’elles reflètent une mauvaise compréhension des versions modernes d’un « principisme spécifié ». Cette approche méthodologique est soucieuse de spécifier les limites de l’application de principes universels en fonction d’une sensibilité aux contextes socioculturels spécifiques et dans le souci d’une ouverture à la discussion éthique participative. Elle offre une nouvelle voie d’articulation des impératifs de sensibilité ethnoculturelle et de respect des droits universels.
Éthique contextuelle ou éthique universelle: un faux débat ? Réflexions issues de la pratique d'essais cliniques en Côte d'Ivoire
Authors: Anglaret Xavier , Msellati Philippe
Published: January 2012

Résumé Il y a un principe éthique universel (le respect de la personne), impliquant des règles également universelles (consentement éclairé, confidentialité, rigueur scientifique...). Leur application se heurte à des difficultés non limitées aux pays en développement, mais qui peuvent s’y révéler plus complexes à résoudre. Pour juger de la qualité des moyens mis en œuvre pour faire respecter ces règles, il existe des indicateurs directs (évaluation des bonnes pratiques, recours aux comités d’éthiques...) et indirects (qualité de la prise en charge des participants, choix des sujets d’étude...). Les doutes liés à l’application de ces règles et à la valeur de ces indicateurs dans certains pays en développement ont nourri une critique simplificatrice venant de pays se posant en gardiens du temple de l’éthique, et fait naître en réaction le concept d’éthique « contextuelle ». Ce concept est dangereux parce que d’une part, il donne l’impression que les doutes exprimés et les questions sans réponse sont réservés aux pays pauvres, alors qu’ils sont inhérents à toute réflexion sur l’éthique; d’autre part, il évite aux pays riches de remettre en question les recherches menées chez eux et pour eux sans aucune référence au droit universel à la santé.
La méthode enracinée
Authors: Garreau Lionel
Published: January 2012

Résumé La théorie enracinée est une méthodologie d’analyse générale qui permet de proposer une théorie à partir de phénomènes identifiés de façon empirique. Nous proposons de questionner la possibilité liée à la mobilisation de la théorie enracinée pour aborder des phénomènes complexes. Nous utiliserons l’étude du concept de sens de façon empirique pour évaluer l’adhérence, la possibilité d’innovation et de généralisation de la théorie enracinée issue de l’opérationnalisation et d’une première modélisation du concept de sens. Nous montrons en quoi la théorie enracinée doit se détacher de la référence à l’induction pure pour passer à une alternance induction - déduction pour parvenir à des résultats à la hauteur de son potentiel de découverte et de rigueur scientifique.
Les liens entre représentation mentale et processus de création d'entreprise
Authors: Bornard Fabienne
Published: January 2012

Résumé Ce papier présente le dispositif méthodologique mis en œuvre dans un projet de recherche étudiant les représentations entrepreneuriales à l’œuvre dans des projets de création d’entreprise suivis « chemin faisant ». Quatre cas de création d’entreprise ont ainsi été observés (et six porteurs de projet), dans le cadre d’un protocole longitudinal. Nous cherchions à comprendre le contenu et l’origine des représentations du projet de création d’entreprise ex-nihilo et comment il peut influencer la conduite (et le résultat ?) du processus. Or l’étude du processus entrepreneurial soulève déjà un certain nombre de difficultés d’ordre méthodologique, qui se sont ajoutées à celles induites par l’étude des représentations mentales. Nous proposons donc de partager les réflexions ayant soutenu l’élaboration du protocole de recherche. Outre son sujet, la cognition entrepreneuriale dans la phase postérieure à la décision de création d’entreprise, ce protocole présente l’intérêt de recourir à des approches originales comme la schématisation et la méthode Visual Card Sort de construction de cartes d’influence.
Les liens entre représentations entrepreneuriales et vision partagée
Authors: Lima Edmilson
Published: January 2012

Résumé Ce texte présente l’approche méthodologique qualitative utilisée dans une recherche longitudinale, d’une durée de cinq ans, qui a abordé un type particulier de représentation entrepreneuriale, à savoir celui de la vision partagée. Ce texte décrit cette approche de recherche en espérant que les apprentissages réalisés puissent être repris et appliqués par d’autres chercheurs. L’approche utilisée associe la théorisation ancrée (grounded theory) à l’analyse de périodes critiques comme stratégie de théorisation à partir de données sur les processus de formation et d’évolution de la vision partagée au sein des équipes de direction de petites et moyennes entreprises (PME). Cette approche a permis de d’obtenir trois bénéfices principaux, dont un promouvant l’efficacité de la combinaison de deux stratégies de théorisation appuyée par l’emploi d’un logiciel d’analyse de données qualitatives dans l’étude de la vision partagée ; un deuxième soulignant à quel point les typologies développées au cours de cette recherche ont pu être fondamentales quant à l’organisation et l’analyse des données selon une grille de lecture favorisant le développement de modèles explicatifs ; et un troisième faisant ressortir à quel point l’importance donnée à l’élaboration de modèles, de représentations graphiques et de tableaux s’est montrée appropriée pour produire la transparence, la facilité de compréhension, ainsi qu’un potentiel de reproduction des méthodes que demande tout projet de recherche abordé suivant une démarche scientifique. Quelques suggestions pour de nouvelles recherches sur la thématique concernée sont mentionnées en conclusion.
Allouer son attention au profil de l'entrepreneur
Authors: Rosa Silvana Bernardes , Morales Sandro Afonso
Published: January 2012

Résumé Ce texte présente l’« entretien ciblé dans le cadre de l’évaluation de compétences entrepreneuriales » ou simplement « l’entretien ciblé », comme outil pour l’évaluation et la mesure du comportement entrepreneurial en vue de l’établissement d’un profil de compétences d’un sujet ou d’une population. Pour cette raison, la méthode de l’« entretien ciblé », telle qu’elle est présentée dans ce texte, est basée sur un modèle de compétences, conçu pour les formations à l’entrepreneuriat et ciblé sur le comportement. Une représentation graphique d’un modèle est proposée pour rendre plus facile la compréhension des compétences dans un système entrepreneurial. La méthode de l’« entretien ciblé » est décrite sous forme d’étapes à suivre. La mise en œuvre de cette méthode demande la maîtrise des concepts de base concernant l’activité entrepreneuriale et la distinction, dans le discours du sujet « entrepreneur », entre ses croyances et ses actions (réalité interne et réalité objective). L’identification des points faibles du profil permet une action de formation en entrepreneuriat, centrée sur le rééquilibrage des compétences et peut rendre plus rapide et efficace un processus d’apprentissage du domaine. La méthodologie permet d’évaluer aussi l’efficacité des actions éducatives par la mesure faite avant et après une action. Elle permet aussi que soit mesuré l’effet d’actions éducatives différentes appliquées à des publics différents, en termes de gains de compétences entrepreneuriales.
Allouer son attention à l'univers des réseaux sociaux
Authors: Barès Franck , Bourgne Patrick , Froehlicher Thomas
Published: January 2012

Résumé Si l’intérêt pour l’analyse des réseaux sociaux au sein de la communauté de chercheurs en gestion est incontestable, il semble important de souligner l’absence d’un travail scientométrique permettant de circonscrire de façon rigoureuse la structuration de cet engouement relativement récent dans le champ de l’entrepreneuriat. Notre contribution répond à ce manque en proposant une approche scientométrique thématique sur la base des publications les plus importantes en sciences de gestion. Pour ce faire, nous avons exploité « Business Source Premier », une des principales bases de données dans le domaine des affaires au niveau mondial.
Allouer son attention aux situations entrepreuneuriales
Authors: Schmitt Christophe
Published: January 2012

Résumé La recherche en entrepreneuriat s’est développée autour de l’entrepreneur (approche par les traits) et de ses actes (approche par les faits). Ces dernières années, on assiste à l’émergence d’une approche complémentaire qui peut être qualifiée d’approche par les processus. Elle nécessite encore d’en préciser le contenu et ses contours. Cet article s’inscrit dans cette perspective. Il a pour point de départ les travaux sur la vision entrepreneuriale, plus particulièrement la dichotomie existante entre le présent et le futur en matière d’entrepreneuriat. Afin de lier futur et présent, l’auteur propose de recourir à une grille lecture originale pour aborder la complexité du phénomène entrepreneurial : les situations entrepreneuriales. Dans la première partie, il s’agit de retracer l’évolution de cette notion dans une perspective temporelle au travers des principales orientations prises par la recherche en entrepreneuriat, et de proposer une définition de la notion de situation entrepreneuriale. La seconde partie s’attache à caractériser les situations entrepreneuriales et amène à introduire d’autres notions telles que l’espace de problématisation, les hypothèses plausibles, la robustesse ou encore, la cohérence.
Du salaire horaire au revenu net : toujours moins pour les femmes
Authors: Meulders Danièle , O’Dorchai Síle , Plasman Robert
Published: January 2012

Résumé Si de nombreuses études traitent des écarts salariaux de genre qu’elles analysent et décomposent, peu d’études s’intéressent aux écarts entre les revenus individuels bruts ou nets des femmes et des hommes. Pourtant, la limitation de l’étude aux inégalités salariales masque une partie importante des inégalités entre les ressources dont disposent les hommes et les femmes. Cet article se base sur des données de la vague 2006 de l’Enquête Européenne sur la Structure des Salaires (ESES) et sur les données 2006 des Statistiques européennes sur le Revenu et les Conditions de Vie (EU-SILC) pour montrer que les inégalités de revenu entre les femmes et les hommes dépassent largement les inégalités de salaires horaires dans les huit pays étudiés. La précarité des femmes ne se limite pas au marché du travail et nécessite des actions politiques plus larges, allant des conditions de travail et de rémunération aux systèmes de sécurité sociale qui leur sont défavorables. Codes JEL : J31, J71
Wages of Occupations in Theory... and Practice
Authors: Kampelmann Stephan , Rycx François
Published: January 2012

Résumé Les modèles conventionnels de rémunération supposent que la structure salariale des professions reflète la distribution des productivités marginales. En dépit de son omniprésence, le fondement empirique de l’hypothèse sous-jacente d’une égalité entre salaire et produit marginal est faible : les études existantes datent des années 1970 et suggèrent que les professions en haut de la hiérarchie salariale sont sur-, et celles en bas sous-payées par rapport à leur contribution à la valeur ajoutée des entreprises. Cet article résume la littérature théorique sur de tels écarts et présente des résultats économétriques récents qui confirment une déconnexion entre rémunérations et productivités des catégories professionnelles. JEL codes: J24, J31, J44.