Letteratura scientifica selezionata sul tema "Consumer equivalence scales"
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Articoli di riviste sul tema "Consumer equivalence scales"
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Jorgenson, Dale W., e Daniel T. Slesnick. "Aggregate Consumer Behavior and Household Equivalence Scales". Journal of Business & Economic Statistics 5, n. 2 (aprile 1987): 219. http://dx.doi.org/10.2307/1391902.
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Jorgenson, Dale W., e Daniel T. Slesnick. "Aggregate Consumer Behavior and Household Equivalence Scales". Journal of Business & Economic Statistics 5, n. 2 (aprile 1987): 219–32. http://dx.doi.org/10.1080/07350015.1987.10509580.
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Bradbury, Bruce. "The welfare interpretation of consumer equivalence scales". International Journal of Social Economics 30, n. 7 (luglio 2003): 770–87. http://dx.doi.org/10.1108/03068290310478739.
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Su, Che-Jen, Hsin-Hsing Liao, Nicolas Lorgnier, Wen-Shen Yen, Patrick Bouchet, Yuichi Hirooka, Rim Jallouli, Mornay Roberts-Lombard e Yi-Fang Lan. "Measuring Adolescent Influence Tactics With Parents in Family Vacation Decisions: A Comparable Scale Across 19 Societies". SAGE Open 9, n. 1 (gennaio 2019): 215824401983595. http://dx.doi.org/10.1177/2158244019835950.
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Exhibiting evidence of the applicability of scales developed in one society to other societies is a critical issue in establishing the general models of consumer behavior. This study investigates the measurement model of adolescent influence tactics with their parents in family vacation decision making in 19 societies. By conducting a series of exploratory and confirmatory factor analyses, adolescent influence behavior emerges in a refined and validated model of four subscales indicating its construct equivalence across societies. Procrustes rotation assessing the similarity of each society’s factor structure reveals a substantial degree of metric equivalence. Moreover, the original measures of influence tactics were relatively free from cross-cultural response bias, achieving the necessary degree of scalar equivalence. Our findings not only furnish future empirical research with cross-societal evidence of the generalized model of measuring adolescent influence behaviors but also highlight the participative role that adolescents play in family vacation decisions.
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Gorostidi-Martinez, Haritz, Weimin Xu e Xiaokang Zhao. "A review of Spanish consumers’ product-country image of China". Asia Pacific Journal of Marketing and Logistics 29, n. 3 (12 giugno 2017): 589–615. http://dx.doi.org/10.1108/apjml-09-2016-0160.
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Purpose The purpose of this paper is to facilitate and clarify the perceptions of Spanish consumers towards China, its people, and its products, while outlining the overall contemporary Chinese product-country image (PCI) within the Spanish market. Design/methodology/approach A 52-item construct was adapted from former PCI scales from cross-cultural equivalence, including “country image”, “personal image”, “product image”, “general knowledge about China”, and “personal data”. Overall, 215 valid structured questionnaires were gathered. Findings The current study provides: a PCI literature review; hypotheses results concerning Spanish citizens’ views of Chinese products’ price, quality, technicality, inventiveness, and known brands concepts; descriptive statistics and results graphs for each of the PCI sections; and correlations of other variables with the five product image variables within the construct. Research limitations/implications Implementing standardized, longitudinal consumer studies that facilitate better comprehension of PCI evolution within a specific market emerged as a future research agenda. Originality/value The data informed both the Chinese public and private organizations’ managers of the importance of adapting to the market and non-market environments within Spain to avoid the liability of country of origin effect.
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Yao, Shuguang, Kaibo Yan, Sisi Lu e Ping Xu. "Equivalence study involving rail vehicle collision test conditions". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, n. 1 (3 giugno 2018): 73–89. http://dx.doi.org/10.1177/0954409718779940.
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In the context of rail vehicle collision tests, which incur high costs and consume substantial time and energy, the equivalence between a single vehicle crashing into a rigid wall and two identical vehicles colliding with each other was studied. Taking the car body as a rigid body, a three-dimensional multi-body dynamic model was built to simulate a single-vehicle impact and a collision between two identical vehicles; the results showed that the condition of a single vehicle crashing into a rigid wall at a speed of [Formula: see text] can be used to replace the condition of one vehicle moving at a speed of v and crashing into an identical vehicle that is stationary. However, the actual collision is a strong nonlinear process, and it is necessary to conduct the equivalent test of the condition of collision. Based on the similarity theory, the scaled equivalent vehicle model is established. Through a series of scaled model tests, the following conclusion is drawn: if one vehicle moving at a speed of vcrashes into another identical vehicle that is stationary, one can equivalently use a single vehicle with a speed of [Formula: see text] (units: m/s) that crashes into a rigid wall. This study provides practical support for the equivalence of vehicle collision test conditions and holds great value for engineering applications.
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Waterhouse, Andrew L. "Consumer Labels can Convey Polyphenolic Content: Implications for Public Health". Clinical and Developmental Immunology 12, n. 1 (2005): 43–46. http://dx.doi.org/10.1080/10446670410001722249.
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Polyphenolics are a large group of related substances. Many of these, in fact much of that found in food, is composed of processing-derived substances too complex for complete identification. Recent studies have suggested likely benefits for diets high in polyphenols, particular in reducing heart disease mortality, but other benefits have also been suggested. A consumer label based on the major polyphenolic classes is both manageable and fairly informative as most foods do not contain all possible classes. Differences between class member can be significant, but data on individual substances is impractical and no data is certainly less informative. Equivalency scales may be useful but may skew content of many foods towards the high-equivalency substances, even while the full beneficial effects of each individual substance is poorly described.
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Qianhui, Gao, Ito Shoichi e Saito Hisamitsu. "Measuring Japan’s technical barriers to trade based on the China’s fruit exports to Japan". Agricultural Economics (Zemědělská ekonomika) 64, No. 3 (16 marzo 2018): 141–47. http://dx.doi.org/10.17221/235/2016-agricecon.
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The study analyses the influence of technical barriers to agricultural trade carried out by Japan on China’s fruit exports. In order to measure the tariff equivalents of technical barriers, the price wedge method is utilized. Based on the utility function specified in the study, the constructed model is adopted to evaluate the elasticity of substitution between the imported fruits and Japanese domestic fruits, and the consumers’ preference parameters for different kinds of fruits. Sample data are chosen from the beginning of 2002 to the end of 2015. Based on the estimated preference parameters and elasticity of substitution, the results show that Japanese consumers prefer domestic fruits to the imported fruits. Besides, the results reveal that although the substitution and preference parameters are higher for the improved quality of imported fruits in the context of the positive list system, the scales of tariff equivalents of technical barriers are larger than the regular custom tariffs, and the technical barriers would cause extra huge costs for the imported fruits. Especially, in the three consecutive years after the implementation of the positive list system, tariff equivalents of technical barriers almost reached 150%, and then gradually decreased in the following years.
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Alamer, Ahmed, Ben Soh e David E. Brumbaugh. "MICKEY 2.0.85: A Secure and Lighter MICKEY 2.0 Cipher Variant with Improved Power Consumption for Smaller Devices in the IoT". Symmetry 12, n. 1 (22 dicembre 2019): 32. http://dx.doi.org/10.3390/sym12010032.
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Lightweight stream ciphers have attracted significant attention in the last two decades due to their security implementations in small devices with limited hardware. With low-power computation abilities, these devices consume less power, thus reducing costs. New directions in ultra-lightweight cryptosystem design include optimizing lightweight cryptosystems to work with a low number of gate equivalents (GEs); without affecting security, these designs consume less power via scaled-down versions of the Mutual Irregular Clocking KEYstream generator—version 2-(MICKEY 2.0) cipher. This study aims to obtain a scaled-down version of the MICKEY 2.0 cipher by modifying its internal state design via reducing shift registers and modifying the controlling bit positions to assure the ciphers’ pseudo-randomness. We measured these changes using the National Institutes of Standards and Testing (NIST) test suites, investigating the speed and power consumption of the proposed scaled-down version named MICKEY 2.0.85. The (85) refers to the new modified bit-lengths of each MICKEY 2.0 register. The results show that it is faster, requires less power, and needs fewer GEs. The proposed variant will enhance the security of applications, such asRadio-frequency identification (RFID) technology, sensor networks, and in Internet of things (IoT) in general. It also will enhance research on the optimization of existing lightweight cryptosystems.
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DeLong, John P. "Energetic inequivalence in eusocial insect colonies". Biology Letters 7, n. 4 (2 marzo 2011): 611–14. http://dx.doi.org/10.1098/rsbl.2011.0036.
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The energetic equivalence rule states that population-level metabolic rate is independent of average body size. This rule has been both supported and refuted by allometric studies of abundance and individual metabolic rate, but no study, to my knowledge, has tested the rule with direct measurements of whole-population metabolic rate. Here, I find a positive scaling of whole-colony metabolic rate with body size for eusocial insects. Individual metabolic rates in these colonies scaled with body size more steeply than expected from laboratory studies on insects, while population size was independent of body size. Using consumer-resource models, I suggest that the colony-level metabolic rate scaling observed here may arise from a change in the scaling of individual metabolic rate resulting from a change in the body size dependence of mortality rates.
Tesi sul tema "Consumer equivalence scales"
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Bradbury, Bruce William Economics Australian School of Business UNSW. "Family Size and Relative Need". Awarded by:University of New South Wales. Economics, 1997. http://handle.unsw.edu.au/1959.4/17174.
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This thesis examines three questions concerned with the relative income needs of families of different sizes - often summarised by indices known as ???equivalence scales???. The first is the extent to which researchers and policy makers should offset the costs of family composition (eg the expenditure costs of children) with the benefits associated with demographic choice (eg the ???joys of parenthood???). Chapter 2 concludes that there are demographic and financial market constraints that will often make a narrow focus on expenditure costs appropriate for distributional research and tax/transfer policies. However, this will not always be the case. One implication of this result is that it may be reasonable for distributional research to use different equivalence scales for adults and children in the same household. Part 2 of the thesis introduces a new method for the estimation of the within-household income distribution and expenditure costs of different family types. This is based upon the household welfare model of Samuelson together with Lau???s method for modelling the joint consumption of household goods. In Chapter 4, this method is applied to the estimation of equivalence scales for older singles and married couples. The estimation is based upon a detailed set of assumptions about the extent of joint consumption for 17 different commodity groups. The main conclusions are that: the theoretical model fits the observed behaviour well (with the exception of some home production effects); that aged couples share their income relatively evenly; and that the relative rate of pension for aged singles in Australia is probably too low. In Part 3, the thesis examines how changes in poverty can be estimated when there is uncertainty about the equivalence scale. The thesis proposes a new method which permits a set of upper and lower bounds for the equivalence scale to be assumed, which in turn determine upper and lower bounds for the increase in poverty. This method is applied to measure the change in poverty in Australia during the 1980s. Equivalence scales can be found that imply either an increase or a decrease in poverty.
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Ohler, Tamara. "Essays on the Rising Demand for Convenience in Meal Provisioning in the United States". 2013. https://scholarworks.umass.edu/open_access_dissertations/760.
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Household food budgets offer a window on consumers' demand for convenience. During the 1980s and 1990s, three shifts likely promoted an increase in the share of the food budget devoted to convenient meal options, namely meals out and prepared foods: the growing number of hours that women spent in paid work, the growing opportunity cost of women's time spent doing housework, and the drop in the price of food relative to all other goods. I test whether the impact of these economic trends (on food budget allocation) was mediated by a change in the impact of children on household meal allocation. I find support for this hypothesis in a model of food away expenditures, which likely reflects two unmeasured shifts. First, (own) child care and household production of meals apparently became substitutes rather than complements. Second, a range of both prepared foods and family-friendly restaurants became available.
The growing demand for time-saving meal options, including frozen food and meals out, has important implications for a core determinant of living standards: the ability to harness scale economies from home production of meals. I test whether greater reliance on convenient meals reduced household-level economies of scale. Other factors could mediate against, or even offset such a loss, including technological advances in the production and distribution of food. Using Engel curve analyses, I find that scale economies fell from 1980 to 2000, thereby reducing living standards; my lower- and upper-bound estimates of the drop are 44 percent and 110 percent respectively.
Economies of scale are not simply a function of household size and composition, as standard equivalence scaling techniques suggest; they are affected by the ways that households trade non-market work and market substitutes. This dissertation contributes to the small literature that challenges the validity of fixed-parameter equivalence scales, such as the per capita scale, which ignore household production. I first attach plausible values to scale parameters and then compare equivalent-income trajectories of parents and non-parents across (standard) fixed parameter and (non-standard) time-varying equivalence scales. I present plausible lower- and upper-bound estimates of the rise in income inequality between parents and non-parents.
Libri sul tema "Consumer equivalence scales"
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Gronau, Reuben. Consumption technology and the intrafamily distribution of resources adult equivalence scales reexamined. Jerusalem: Hebrew University of Jerusalem, Dept. of Economics, 1985.
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Blokland, J. Continuous Consumer Equivalence Scales: Item-specific effects of age and sex of household members in the budget allocation model. Springer, 2011.
Cerca il testo completoCapitoli di libri sul tema "Consumer equivalence scales"
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Jurado, Enrique Bernal, Adoración Mozas Moral e Miguel J. Medina Viruel. "Internet as a Sales Channel for the Agri-Food Sector". In Electronic Payment Systems for Competitive Advantage in E-Commerce, 15–29. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-5190-6.ch002.
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The Spanish market for organic products is notable for a supply side that offers one of the largest ranges in the world and a demand side that can only be termed symbolic. The reasons that have been given for this situation include the few and scattered points of sale, higher prices than for the conventional equivalents, and the consumers' disinformation about this product range. The Internet offers solutions to these barriers that some companies have used to facilitate online transactions in organic products. The case study presented in this chapter focuses on examining a virtual platform managed by an intermediary, not a producer, which puts producers and consumers of organic products in direct contact with each other. Making use of the Internet's advantages as a sales channel, developing a differentiation strategy based on promoting values such as the environment and sustainability, and the company's mutualist relationship with its small-scale suppliers have generated an associate and customer base that ensures the success of this business model.
Atti di convegni sul tema "Consumer equivalence scales"
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Arruda, David, David Browne, Chris Thongkham e Mansour Zenouzi. "Small-Scale, Green-Powered Hydrogen Generation System". In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68760.
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One of the major road blocks in the transition from the current oil economy to the future hydrogen fuel economy is the availability of low cost hydrogen fuel for the average consumer. Currently, the price per kilogram of hydrogen fuel is higher than the cost of an equivalent measure of gasoline and its availability is limited to large metropolitan areas. Both of these factors prevent hydrogen from being an attractive alternative to gasoline for most consumers. The goal of this project, in a senior thermal design course, is to design and construct a low-cost hydrogen generation system for residential hydrogen fuel production and storage. The system will be powered by renewable sources of energy; namely a micro-scale wind turbine and a solar panel. The power generated will be used to power a small-scale PEM electrolyzer to produce hydrogen gas that will then be stored at low pressure in a safe, metal hydride storage tank. This relatively low cost system will provide the average consumer with the ability to safely produce hydrogen fuel for use in residential fuel cells or fuel cell-powered vehicles, making hydrogen fuel an attractive alternative to fossil fuels.
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Cudney, Elizabeth A., Kenneth M. Ragsdell e Kioumars Paryani. "Applying the Mahalanobis-Taguchi System to Vehicle Ride". In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13161.
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The Mahalanobis Taguchi System is a diagnosis and forecasting method for multivariate data. Mahalanobis distance is a measure based on correlations between the variables and different patterns that can be identified and analyzed with respect to a base or reference group. The Mahalanobis-Taguchi System is of interest because of its reported accuracy in forecasting small, correlated data sets. This is the type of data that is encountered with consumer vehicle ratings. MTS enables a reduction in dimensionality and the ability to develop a scale based on MD values. MTS identifies a set of useful variables from the complete data set with equivalent correlation and considerably less time and data. This paper presents the application of the Mahalanobis-Taguchi System and its application to identify a reduced set of useful variables in multidimensional systems.
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Cudney, Elizabeth A., Kioumars Paryani e Kenneth M. Ragsdell. "Applying the Mahalanobis-Taguchi System to Vehicle Handling". In ASME 2006 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/detc2006-99133.
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The Mahalanobis Taguchi System (MTS) is a diagnosis and forecasting method for multivariate data. Mahalanobis Distance (MD) is a measure based on correlations between the variables and different patterns that can be identified and analyzed with respect to a base or reference group. The MTS is of interest because of its reported accuracy in forecasting from small, correlated data sets. This is the type of data that is encountered with consumer vehicle ratings. MTS enables a reduction in dimensionality and the ability to develop a scale based on MD values. MTS identifies a set of useful variables from the complete data set with equivalent correlation and considerably less time and data. This paper presents the application of the MTS, its applicability in identifying a reduced set of useful variables in multidimensional systems.
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Aggarwal, S. K., e H. S. Xue. "The Structure of Two-Stage Counterflow n-Heptane-Air Flames". In ASME Turbo Expo 2000: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/2000-gt-0134.
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Partially premixed flames are formed by mixing air (in less than stoichiometric amounts) into the fuel stream prior to the reaction zone, where additional air is available for complete combustion. Such flames can occur in both laboratory and practical combustion systems. In advanced gas turbine combustor designs, such as a lean direct injection (LDI) combustor, partially premixed combustion represents an impotent mode of burning. Spray combustion often involves partially premixed combustion due to the locally fuel vapor-rich regions. In the present study, the detailed structure of n-heptane/air partially premixed flame in a counterflow configuration is investigated. The flame is computed by employing the Oppdif code and a detailed reaction mechanism consisting of 275 elementary reactions and 41 species. The partially premixed flame structure is characterized by two-stage burning or two distinct but synergistically coupled reaction zones, a rich premixed zone on the fuel side and a ‘nonpremixed zone on the air side. The fuel is completely consumed in the premixed zone with ethylene and acetylene being the major intermediate species. The reactions involving the consumption of these species are found to be the key rate-limiting reactions that characterize interactions between the two reaction zones, and determine the overall fuel consumption rate. The flame response to the variations in equivalence ratio and strain rate is examined. Increasing equivalence ratio and/or strain rate to a critical value leads to merging of the two reaction zones. The equivalence ratio variation affects the rich premixed reaction zone, while the variation in strain rate predominantly affects the nonpremixed reaction zone. The flame structure is also characterized in terms of a modified mixture fraction (conserved scalar), and laminar flamelet profiles are provided.
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Şengül, Seda, e Çiler Sigeze. "The Consumption Expenditure of Households in Turkey: Demand System Estimation with Pseudo Panel Data". In International Conference on Eurasian Economies. Eurasian Economists Association, 2013. http://dx.doi.org/10.36880/c04.00709.
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In this study, micro data sets obtained by 2005 and 2009 Household Budget Surveys compiled by Turkish Statistical Institute were used to estimate the parameters of household consumption demand and calculate the income-demand elasticities of consumer goods. Total expenditures of the households in this data set delivered into the following 12 different categories of goods and services. The expenditure share of these different categories of goods and services is the dependent variable of this model. In addition, the total household expenditure, the squared total household expenditure, the household size adjusted in accordance with the OECD equivalence scale and the logarithms of squared household size are the independent variables used in the study. The Seemingly Unrelated Regression Equations (SURE) is used to estimate the Quadratic Almost Ideal Demand System (QAIDS) so as to determine the demand parameters of the main commodity groups. The principal result of the study is that the consumption elasticities of the food and nonalcoholic beverages, housing, water, electricity, fuel, clothing and footwear, furniture and house appliances, communications, alcoholic beverages, cigarette and tobacco expenditure are less than 1. Therefore, it can be said that these commodity groups are considered to be mandatory goods. On the other hand, the consumption elasticities of the health, transportation, education services, entertainment and culture, restaurants, hotels, patisseries are more than 1. Thus, these commodity groups are considered to be luxury goods. In this regard, the study concludes that Turkey is considered to be a developing country in terms of the consumption characteristics.
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Johnson, Matthew, e Delcie Durham. "Establishing Relationships Between Manufacturing Sustainability and Performance". In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28913.
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The current LCA methods assess a product’s sustainability over its full life cycle, cradle-to-grave. While the number(s) obtained detail the contributions a process makes to a product in terms of energy intensity or the generation of wastes, it is insufficient to optimize a process for both sustainability and performance objectives. The Economic Input/Output Life Cycle Analysis (EIO-LCA) was used to investigate whether metrics could be identified which address sustainability — performance issues in materials processing. This method lends itself to the assessment of processes on a unit time basis while allowing for calculation of resources used and byproducts expelled. Productivity of manufacturing processes is also based on time. For example, material removal rate is related to processing feed, speed, and the geometry and tolerances established during design. A scaled waterjet cutting process was tested to investigate the unit time relationships. The EIO-LCA was conducted and the subsequent environmental impact in the form of total energy consumed and equivalent CO2 expelled evaluated per unit time, establishing the relationship to cutting speed. Although this is a static LCA at set conditions, it suggests that relationships can be explored between the regulation of resources, productivity, cost and environmental impact by varying the processing parameters.
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Manikantachari, K. R. V., Scott Martin, Ladislav Vesely, Jose O. Bobren-Diaz, Subith Vasu e Jayanta Kapat. "A Strategy of Reactant Mixing in Methane Direct-Fired sCO2 Combustors". In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75547.
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The sCO2 power cycle concept is identified as a potentially efficient, economical, and pollutant free power generation technique for future power generation. Recent work in the literature provides some strategies and best operating conditions for direct-fired sCO2 combustors based on zero-dimensional reactor modeling analysis, however there is a need for a detailed investigation using accurate combustion chemical kinetics and thermophysical models. Here, the sCO2 combustor is modelled by coupling perfectly stirred reactor (PSR) and plug flow reactor (PFR) models. The real gas effects are incorporated using the Soave-Redlich-Kwong (SRK) equation of state. Also, the detailed Aramco 2.0 kinetic mechanism is used for the combustion kinetic rates. It is found that the primary zone must be diluted either with thirty or forty-five percent of the total CO2 in the cycle to have a feasible combustor design. However, the forty-five percent dilution level at 950 K and 1000 K yielded a better consumption of CO, O2 and CH4. Also, the cross-sectional area of the sCO2 combustor can be scaled-down to 10 to 20 times smaller than a traditional combustor with the same power output. Further, from this investigation, it is also recommended to have a gradually increasing secondary dilution in the dilution zone, by using progressively larger diameter holes. This design would help retain relatively high temperature in the initial portion of the dilution zone and would help consume fuel species such as, CO and CH4. It appears that, for sCO2 combustors “lean burn” is the better strategy over stoichiometric burning to eliminate CO build up at the combustor exit. The lean burn condition at equivalence ratio (ϕ) equal to 0.9 is recommended for sCO2 combustor operation. Also, the length of the dilution zone can be scaled-down to 50% by lean burn operation of the combustor. It is also observed that the lean burn increases the net turbine power. Current work provides crucial design considerations for the development of advanced sCO2 combustors to be used with direct-fired power cycles.
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Oduru, Soumith Kumar, e Pasi Lautala. "Incorporating Life Cycle Assessment (LCA) in Freight Transportation Infrastructure Project Evaluation". In 2017 Joint Rail Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/jrc2017-2303.
Testo completoAbstract (sommario):
Transportation industry at large is a major consumer of fossil fuels and contributes heavily to the global greenhouse gas emissions. A significant portion of these emissions come from freight transportation and decisions on mode/route may affect the overall scale of emissions from a specific movement. It is common to consider several alternatives for a new freight activity and compare the alternatives from economic perspective. However, there is a growing emphasis for adding emissions to this evaluation process. One of the approaches to do this is through Life Cycle Assessment (LCA); a method for estimating the emissions, energy consumption and environmental impacts of the project throughout its life cycle. Since modal/route selections are often investigated early in the planning stage of the project, availability of data and resources for analysis may become a challenge for completing a detailed LCA on alternatives. This research builds on such detailed LCA comparison performed on a previous case study by Kalluri et al. (2016), but it also investigates whether a simplified LCA process that only includes emissions from operations phase could be used as a less resource intensive option for the analysis while still providing relevant outcomes. The detailed LCA is performed using SimaPro software and simplified LCA is performed using GREET 2016 model. The results are obtained in terms of Kg CO2 equivalents of GHG emissions. This paper introduces both detailed and simplified methodologies and applies them to a case study of a nickel and copper mine in the Upper Peninsula of Michigan. The analysis’ are done for three modal alternatives (two truck routes and one rail route) and for multiple mine lives.
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Hinkeldey, O., R. Koch, H. J. Bauer, M. Cano-Wolff e P. Schober. "Laser Based Study of Spray Auto-Ignition in a Generic Mixing Duct". In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50143.
Testo completoAbstract (sommario):
Auto-ignition is one of the challenges still inhibiting the application of LPP combustion in aero-engine turbines. In this context, the auto-ignition phenomenon in a droplet-laden reactive flow was investigated. The test rig used for this investigation has optical access to the reaction zone and allows systematic parametric studies of auto-ignition. The investigations are focused on a detailed understanding of the local conditions under which auto-ignition of fuel spray may occur. The fuel droplets are injected into a rapid flow (> 30m/s) of heated, non-vitiated air at elevated gas pressure (0.8MPa). The auto-ignition and subsequent combustion of kerosene or heptane fuel spray were investigated over the technically interesting range of air temperatures (750...1100K). The global equivalence ratio of the fuel/air mixture was lean (Φ = 0.6). The chemical reactions were visualized by planar laser-induced fluorescence (LIF) of formaldehyde (CH2O), which is formed as an intermediate species in the reactions leading to auto-ignition and subsequently consumed during combustion. The LIF of CH2O was excited by a dye-laser at 339.3nm and captured by an ICCD camera. For the visualization of incompletely evaporated droplets, simultaneous imaging of Mie-scattering with a second laser-camera-arrangement at 532nm was performed. Additionally, high-speed sequences of the flame luminosity were taken. The chemiluminescence signal was captured broadband as well as spectrally filtered by different adequate dielectric filters. With this method it was possible to discriminate between the fractions of OH* and CH* radicals as well as from radiation at longer wavelengths that can be attributed to “young soot”. The analysis of images obtained from the Mie, LIF and chemiluminescence signals, shows the simultaneous occurrence of multiple phases in the droplet vaporization/ignition/combustion sequence. CH2O-LIF intensity fields display pronounced large-scale inhomogeneities, with smooth spatial transitions between lower and higher CH2O-levels, indicating different levels of reaction progress at different locations. Some images show spatially coherent zones of complete formaldehyde consumption with sharp gradients in the CH2O-LIF fields, indicating flame-like combustion. This occurrence of isolated combusting regions suggests individual flame zones that develop from spatially separated, independent auto-ignition spots. Furthermore, individual small spots of high intensity were observed, originating from droplets that are burned under fuel rich conditions inside the hot products of the expanding flame zones. On the basis of the simultaneous LIF and Mie observations, however, a correlation of the location of ignition and the bigger residual droplets could not be confirmed, though this was inferred from single droplet investigations in literature. The impact of droplets’ boundary layers in a turbulent mixing duct flow seems to be of minor importance concerning the promotion of ignition kernels. Overall, the experiments show that auto-ignition of fuel sprays in a premixing duct requires a more detailed modeling than plain treatment of a single droplet with ambient gas phase.