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Sample records for demand elasticities

  1. Price Elasticity of Alcohol Demand in India.

    PubMed

    Kumar, Santosh

    2017-05-01

    Using a household survey conducted in 2014, this study estimates price elasticity of demand (PED) for beer, country liquor and spirits in India. Ordinary least-square models were used to estimate the responsiveness in alcohol demand due to price change. A large number of control variables were included to adjust for potential confounding in the model. Inter-district variation in alcohol consumption is adjusted for by including district fixed effects. Alcohol prices are negatively associated with demand for alcoholic beverages. The PED ranged from -0.14 for spirits to -0.46 for country liquor. Low level of education was positively associated with spirits consumption. The magnitude of elasticity varied by rural-urban, education and gender. Results indicate that a policy mix of price controls and awareness campaigns would be most effective in tackling the adverse effects of harmful drinking in India. The demand for beer, country liquor and spirits is negatively associated with its own price. The elasticity estimates ranged from -0.14 for spirits to -0.44 for country liquor. The elasticity estimates varied by rural-urban, gender and by education levels of the drinkers.

  2. A Note on Comparing the Elasticities of Demand Curves.

    ERIC Educational Resources Information Center

    Nieswiadomy, Michael

    1986-01-01

    Demonstrates a simple and useful way to compare the elasticity of demand at each price (or quantity) for different demand curves. The technique is particularly useful for the intermediate microeconomic course. (Author)

  3. A Note on Comparing the Elasticities of Demand Curves.

    ERIC Educational Resources Information Center

    Nieswiadomy, Michael

    1986-01-01

    Demonstrates a simple and useful way to compare the elasticity of demand at each price (or quantity) for different demand curves. The technique is particularly useful for the intermediate microeconomic course. (Author)

  4. Consumer Brand Choice: Individual and Group Analyses of Demand Elasticity

    PubMed Central

    Oliveira-Castro, Jorge M; Foxall, Gordon R; Schrezenmaier, Teresa C

    2006-01-01

    Following the behavior-analytic tradition of analyzing individual behavior, the present research investigated demand elasticity of individual consumers purchasing supermarket products, and compared individual and group analyses of elasticity. Panel data from 80 UK consumers purchasing 9 product categories (i.e., baked beans, biscuits, breakfast cereals, butter, cheese, fruit juice, instant coffee, margarine and tea) during a 16-week period were used. Elasticity coefficients were calculated for individual consumers with data from all or only 1 product category (intra-consumer elasticities), and for each product category using all data points from all consumers (overall product elasticity) or 1 average data point per consumer (interconsumer elasticity). In addition to this, split-sample elasticity coefficients were obtained for each individual with data from all product categories purchased during weeks 1 to 8 and 9 to 16. The results suggest that: 1) demand elasticity coefficients calculated for individual consumers purchasing supermarket food products are compatible with predictions from economic theory and behavioral economics; 2) overall product elasticities, typically employed in marketing and econometric research, include effects of interconsumer and intraconsumer elasticities; 3) when comparing demand elasticities of different product categories, group and individual analyses yield similar trends; and 4) individual differences in demand elasticity are relatively consistent across time, but do not seem to be consistent across products. These results demonstrate the theoretical, methodological, and managerial relevance of investigating the behavior of individual consumers. PMID:16673823

  5. Consumer brand choice: individual and group analyses of demand elasticity.

    PubMed

    Oliveira-Castro, Jorge M; Foxall, Gordon R; Schrezenmaier, Teresa C

    2006-03-01

    Following the behavior-analytic tradition of analyzing individual behavior, the present research investigated demand elasticity of individual consumers purchasing supermarket products, and compared individual and group analyses of elasticity. Panel data from 80 UK consumers purchasing 9 product categories (i.e., baked beans, biscuits, breakfast cereals, butter, cheese, fruit juice, instant coffee, margarine and tea) during a 16-week period were used. Elasticity coefficients were calculated for individual consumers with data from all or only 1 product category (intra-consumer elasticities), and for each product category using all data points from all consumers (overall product elasticity) or 1 average data point per consumer (interconsumer elasticity). In addition to this, split-sample elasticity coefficients were obtained for each individual with data from all product categories purchased during weeks 1 to 8 and 9 to 16. The results suggest that: 1) demand elasticity coefficients calculated for individual consumers purchasing supermarket food products are compatible with predictions from economic theory and behavioral economics; 2) overall product elasticities, typically employed in marketing and econometric research, include effects of interconsumer and intraconsumer elasticities; 3) when comparing demand elasticities of different product categories, group and individual analyses yield similar trends; and 4) individual differences in demand elasticity are relatively consistent across time, but do not seem to be consistent across products. These results demonstrate the theoretical, methodological, and managerial relevance of investigating the behavior of individual consumers.

  6. Price elasticity of demand: An overlooked concept

    SciTech Connect

    1995-10-01

    An all-too-common mistake in analyzing the uranium market is to assume that demand for uranium is driven only by the design and operational parameters of nuclear power plants. Because it is generally accepted that demand for uranium is inelastic, not much attention has been given to how prices can indirectly affect demand. The purpose of this paper is to highlight the factors that are most sensitive to uranium prices, and to show how they alter uranium demand.

  7. Consumer Brand Choice: Individual and Group Analyses of Demand Elasticity

    ERIC Educational Resources Information Center

    Oliveira-Castro, Jorge M.; Foxall, Gordon R.; Schrezenmaier, Teresa C.

    2006-01-01

    Following the behavior-analytic tradition of analyzing individual behavior, the present research investigated demand elasticity of individual consumers purchasing supermarket products, and compared individual and group analyses of elasticity. Panel data from 80 UK consumers purchasing 9 product categories (i.e., baked beans, biscuits, breakfast…

  8. Consumer Brand Choice: Individual and Group Analyses of Demand Elasticity

    ERIC Educational Resources Information Center

    Oliveira-Castro, Jorge M.; Foxall, Gordon R.; Schrezenmaier, Teresa C.

    2006-01-01

    Following the behavior-analytic tradition of analyzing individual behavior, the present research investigated demand elasticity of individual consumers purchasing supermarket products, and compared individual and group analyses of elasticity. Panel data from 80 UK consumers purchasing 9 product categories (i.e., baked beans, biscuits, breakfast…

  9. The Arc Elasticity of Demand: A Note and Comment.

    ERIC Educational Resources Information Center

    Vaughan, Michael B.

    1988-01-01

    Examines the suitability of the traditional arc elasticity measure as a component of the economics curriculum. Demonstrates that the midpoint measure is subject to shortcomings as it invariably approaches one when price changes become large. Discusses point elasticity of demand as an alternative to the midpoint measure in the principles course.…

  10. The Arc Elasticity of Demand: A Note and Comment.

    ERIC Educational Resources Information Center

    Vaughan, Michael B.

    1988-01-01

    Examines the suitability of the traditional arc elasticity measure as a component of the economics curriculum. Demonstrates that the midpoint measure is subject to shortcomings as it invariably approaches one when price changes become large. Discusses point elasticity of demand as an alternative to the midpoint measure in the principles course.…

  11. Irrigation water demand: A meta-analysis of price elasticities

    NASA Astrophysics Data System (ADS)

    Scheierling, Susanne M.; Loomis, John B.; Young, Robert A.

    2006-01-01

    Metaregression models are estimated to investigate sources of variation in empirical estimates of the price elasticity of irrigation water demand. Elasticity estimates are drawn from 24 studies reported in the United States since 1963, including mathematical programming, field experiments, and econometric studies. The mean price elasticity is 0.48. Long-run elasticities, those that are most useful for policy purposes, are likely larger than the mean estimate. Empirical results suggest that estimates may be more elastic if they are derived from mathematical programming or econometric studies and calculated at a higher irrigation water price. Less elastic estimates are found to be derived from models based on field experiments and in the presence of high-valued crops.

  12. Estimating elasticity for residential electricity demand in China.

    PubMed

    Shi, G; Zheng, X; Song, F

    2012-01-01

    Residential demand for electricity is estimated for China using a unique household level dataset. Household electricity demand is specified as a function of local electricity price, household income, and a number of social-economic variables at household level. We find that the residential demand for electricity responds rather sensitively to its own price in China, which implies that there is significant potential to use the price instrument to conserve electricity consumption. Electricity elasticities across different heterogeneous household groups (e.g., rich versus poor and rural versus urban) are also estimated. The results show that the high income group is more price elastic than the low income group, while rural families are more price elastic than urban families. These results have important policy implications for designing an increasing block tariff.

  13. Estimating Elasticity for Residential Electricity Demand in China

    PubMed Central

    Shi, G.; Zheng, X.; Song, F.

    2012-01-01

    Residential demand for electricity is estimated for China using a unique household level dataset. Household electricity demand is specified as a function of local electricity price, household income, and a number of social-economic variables at household level. We find that the residential demand for electricity responds rather sensitively to its own price in China, which implies that there is significant potential to use the price instrument to conserve electricity consumption. Electricity elasticities across different heterogeneous household groups (e.g., rich versus poor and rural versus urban) are also estimated. The results show that the high income group is more price elastic than the low income group, while rural families are more price elastic than urban families. These results have important policy implications for designing an increasing block tariff. PMID:22997492

  14. Health care demand elasticities by type of service.

    PubMed

    Ellis, Randall P; Martins, Bruno; Zhu, Wenjia

    2017-09-01

    We estimate within-year price elasticities of demand for detailed health care services using an instrumental variable strategy, in which individual monthly cost shares are instrumented by employer-year-plan-month average cost shares. A specification using backward myopic prices gives more plausible and stable results than using forward myopic prices. Using 171 million person-months spanning 73 employers from 2008 to 2014, we estimate that the overall demand elasticity by backward myopic consumers is -0.44, with higher elasticities of demand for pharmaceuticals (-0.44), specialists visits (-0.32), MRIs (-0.29) and mental health/substance abuse (-0.26), and lower elasticities for prevention visits (-0.02) and emergency rooms (-0.04). Demand response is lower for children, in larger firms, among hourly waged employees, and for sicker people. Overall the method appears promising for estimating elasticities for highly disaggregated services although the approach does not work well on services that are very expensive or persistent. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Using FRED Data to Teach Price Elasticity of Demand

    ERIC Educational Resources Information Center

    Méndez-Carbajo, Diego; Asarta, Carlos J.

    2017-01-01

    In this article, the authors discuss the use of Federal Reserve Economic Data (FRED) statistics to teach the concept of price elasticity of demand in an introduction to economics course. By using real data in its computation, they argue that instructors can create a value-adding context for illustrating and applying a foundational concept in…

  16. Teaching Price, Income, and Cross Elasticity of Demand: Another Approach.

    ERIC Educational Resources Information Center

    Zahka, William J.

    One of the most important, yet difficult concepts to teach in an undergraduate course in intermediate microeconomics is the all-embracing concept of elasticity of demand. This paper details a four part teaching approach developed to make this most important aspect of microeconomic theory more understandable. Part 1 develops the approach for…

  17. The Cross-Elasticity of Demand for National Newspaper Advertising.

    ERIC Educational Resources Information Center

    Busterna, John C.

    1987-01-01

    Measures the extent to which other media compete with newspapers in the market for national advertising, using coefficients of the cross-elasticity of demand between newspapers and eight other media. Concluded that no other media reside in the same product market for national advertising. (MM)

  18. Teaching Price, Income, and Cross Elasticity of Demand: Another Approach.

    ERIC Educational Resources Information Center

    Zahka, William J.

    One of the most important, yet difficult concepts to teach in an undergraduate course in intermediate microeconomics is the all-embracing concept of elasticity of demand. This paper details a four part teaching approach developed to make this most important aspect of microeconomic theory more understandable. Part 1 develops the approach for…

  19. ROLE OF ESTROGEN RECEPTOR-α ON FOOD DEMAND ELASTICITY

    PubMed Central

    Minervini, Vanessa; Rowland, Neil E.; Robertson, Kimberly L.; Foster, Thomas C.

    2016-01-01

    Estrogens have been shown to have an inhibitory effect on food intake under free-feeding conditions, yet the effects of estrogens on food-maintained operant responding have been studied to a much lesser extent and, thus, are not well understood. Therefore, the purpose of the present experiment was to use a behavioral economics paradigm to assess differences in demand elasticity between mice with knockout of the estrogen receptor subtype α, knockout of subtype β, and their wild type controls. The mice responded in a closed economy, and the price of food was increased by increasing the fixed-ratio response requirement every four sessions. Overall, we found that mice with the knockout of receptor subtype α had the most elastic demand functions. Therefore, under these conditions, estrogens increased food seeking via activation of the receptor subtype α. The results were inconsistent with those reported by previous studies that employed free-feeding conditions. PMID:25869426

  20. Role of estrogen receptor-α on food demand elasticity.

    PubMed

    Minervini, Vanessa; Rowland, Neil E; Robertson, Kimberly L; Foster, Thomas C

    2015-05-01

    Estrogens have been shown to have an inhibitory effect on food intake under free-feeding conditions, yet the effects of estrogens on food-maintained operant responding have been studied to a much lesser extent and, thus, are not well understood. Therefore, the purpose of the present experiment was to use a behavioral economics paradigm to assess differences in demand elasticity between mice with knockout of the estrogen receptor subtype α, knockout of subtype β, and their wild type controls. The mice responded in a closed economy, and the price of food was increased by increasing the fixed-ratio response requirement every four sessions. Overall, we found that mice with the knockout of receptor subtype α had the most elastic demand functions. Therefore, under these conditions, estrogens increased food seeking via activation of the receptor subtype α. The results were inconsistent with those reported by previous studies that employed free-feeding conditions.

  1. Relationship between the Uncompensated Price Elasticity and the Income Elasticity of Demand under Conditions of Additive Preferences

    PubMed Central

    Sabatelli, Lorenzo

    2016-01-01

    Income and price elasticity of demand quantify the responsiveness of markets to changes in income and in prices, respectively. Under the assumptions of utility maximization and preference independence (additive preferences), mathematical relationships between income elasticity values and the uncompensated own and cross price elasticity of demand are here derived using the differential approach to demand analysis. Key parameters are: the elasticity of the marginal utility of income, and the average budget share. The proposed method can be used to forecast the direct and indirect impact of price changes and of financial instruments of policy using available estimates of the income elasticity of demand. PMID:26999511

  2. Relationship between the Uncompensated Price Elasticity and the Income Elasticity of Demand under Conditions of Additive Preferences.

    PubMed

    Sabatelli, Lorenzo

    2016-01-01

    Income and price elasticity of demand quantify the responsiveness of markets to changes in income and in prices, respectively. Under the assumptions of utility maximization and preference independence (additive preferences), mathematical relationships between income elasticity values and the uncompensated own and cross price elasticity of demand are here derived using the differential approach to demand analysis. Key parameters are: the elasticity of the marginal utility of income, and the average budget share. The proposed method can be used to forecast the direct and indirect impact of price changes and of financial instruments of policy using available estimates of the income elasticity of demand.

  3. Synthesizing Econometric Evidence: The Case of Demand Elasticity Estimates.

    PubMed

    DeCicca, Philip; Kenkel, Don

    2015-06-01

    Econometric estimates of the responsiveness of health-related consumer demand to higher prices are often key ingredients for risk policy analysis. We review the potential advantages and challenges of synthesizing econometric evidence on the price-responsiveness of consumer demand. We draw on examples of research on consumer demand for health-related goods, especially cigarettes. We argue that the overarching goal of research synthesis in this context is to provide policy-relevant evidence for broad-brush conclusions. We propose three main criteria to select among research synthesis methods. We discuss how in principle and in current practice synthesis of research on the price-elasticity of smoking meets our proposed criteria. Our analysis of current practice also contributes to academic research on the specific policy question of the effectiveness of higher cigarette prices to reduce smoking. Although we point out challenges and limitations, we believe more work on research synthesis in this area will be productive and important.

  4. Price elasticities of alcohol demand: evidence from Russia.

    PubMed

    Goryakin, Yevgeniy; Roberts, Bayard; McKee, Martin

    2015-03-01

    In this paper, we estimate price elasticities of demand of several types of alcoholic drinks, using 14 rounds of data from the Russia Longitudinal Monitoring Survey-HSE, collected from 1994 until 2009. We deal with potential confounding problems by taking advantage of a large number of control variables, as well as by estimating community fixed effect models. All in all, although alcohol prices do appear to influence consumption behaviour in Russia, in most cases the size of effect is modest. The finding that two particularly problematic drinks-cheap vodka and fortified wine-are substitute goods also suggests that increasing their prices may not lead to smaller alcohol consumption. Therefore, any alcohol pricing policies in Russia must be supplemented with other measures, such as restrictions on numbers of sales outlets or their opening times.

  5. Optimal Electricity Charge Strategy Based on Price Elasticity of Demand for Users

    NASA Astrophysics Data System (ADS)

    Li, Xin; Xu, Daidai; Zang, Chuanzhi

    The price elasticity is very important for the prediction of electricity demand. This paper mainly establishes the price elasticity coefficient for electricity in single period and inter-temporal. Then, a charging strategy is established based on these coefficients. To evaluate the strategy proposed, simulations of the two elastic coefficients are carried out based on the history data of a certain region.

  6. Price Elasticities of Food Demand: Compensated vs Uncompensated.

    PubMed

    Clements, Kenneth W; Si, Jiawei

    2016-11-01

    Two recent studies have provided a comprehensive review/summary of a large number of estimates of the price elasticity of food consumption using a meta-regression approach. In this letter, we introduce a way of removing the income effect from these elasticities to recover the compensated elasticities. Although the income effect is small, the compensated elasticities vary by income group. Both types of elasticity should possibly be considered when assessing the impact of policy changes on food consumption. Copyright © 2015 John Wiley & Sons, Ltd.

  7. [Study on elasticity of medical service demand at the township level in China].

    PubMed

    Shi, Hong-xing; Lv, Jun; Xie, Yi-ping; Wang, Ying; Jia, Jin-zhong; Chang, Feng-shui; Duan, Lin; Sun, Mei; Wang, Zhi-feng; Hao, Mo

    2010-06-18

    To find out the economic laws regulating medical service demand in accordance with influencing factors at the township level, thus to provide references for further adjusting the medical service demand reasonably in the future. The model of medical service demand was established to measure the elasticity of demand in 49 township health clinics in 1995, 1999, 2003 and 2007. The price elasticity of outpatient and inpatient demand was stable during the four periods, and the average value was -0.029 and -0.132 respectively; the average value of income elasticity was 0.973 and 0.977, registering a downward trend in general. The medical service demand at the township level is price inelastic, indicating that it is a necessity for rural residents. The downward trend of income elasticity under the influence of some health policies illustrates a lightening in economic burden for medical service demand among rural residents in township health clinics.

  8. Examining the short-run price elasticity of gasoline demand in the United States

    NASA Astrophysics Data System (ADS)

    Brannan, Michael James

    Estimating the consumer demand response to changes in the price of gasoline has important implications regarding fuel tax policies and environmental concerns. There are reasons to believe that the short-run price elasticity of gasoline demand fluctuates due to changing structural and behavioral factors. In this paper I estimate the short-run price elasticity of gasoline demand in two time periods, from 2001 to 2006 and from 2007 to 2010. This study utilizes data at both the national and state levels to produce estimates. The short-run price elasticities range from -0.034 to -0.047 during 2001 to 2006, compared to -0.058 to -0.077 in the 2007 to 2010 period. This paper also examines whether there are regional differences in the short-run price elasticity of gasoline demand in the United States. However, there appears to only be modest variation in price elasticity values across regions.

  9. Price elasticity reconsidered: Panel estimation of an agricultural water demand function

    NASA Astrophysics Data System (ADS)

    Schoengold, Karina; Sunding, David L.; Moreno, Georgina

    2006-09-01

    Using panel data from a period of water rate reform, this paper estimates the price elasticity of irrigation water demand. Price elasticity is decomposed into the direct effect of water management and the indirect effect of water price on choice of output and irrigation technology. The model is estimated using an instrumental variables strategy to account for the endogeneity of technology and output choices in the water demand equation. Estimation results indicate that the price elasticity of agricultural water demand is -0.79, which is greater than that found in previous studies.

  10. 39 CFR 3050.26 - Documentation of demand elasticities and volume forecasts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Postal Service shall provide econometric estimates of demand elasticity for all postal products accompanied by the underlying econometric models and the input data sets used; and a volume forecast for...

  11. On using sample selection methods in estimating the price elasticity of firms' demand for insurance.

    PubMed

    Marquis, M Susan; Louis, Thomas A

    2002-01-01

    We evaluate a technique based on sample selection models that has been used by health economists to estimate the price elasticity of firms' demand for insurance. We demonstrate that, this technique produces inflated estimates of the price elasticity. We show that alternative methods lead to valid estimates.

  12. Using the Price Elasticity of Demand in Educational Decision Making.

    ERIC Educational Resources Information Center

    Smith, Joseph D.; Moracco, Judy N.

    1984-01-01

    Describes a study and methods used by Navy Campus to choose a funding arrangement that would make the best use of the money available for voluntary educational purposes. Discusses modifying the economic concept of price elasticity to the interests of educationally oriented audiences. (JOW)

  13. Using the Price Elasticity of Demand in Educational Decision Making.

    ERIC Educational Resources Information Center

    Smith, Joseph D.; Moracco, Judy N.

    1984-01-01

    Describes a study and methods used by Navy Campus to choose a funding arrangement that would make the best use of the money available for voluntary educational purposes. Discusses modifying the economic concept of price elasticity to the interests of educationally oriented audiences. (JOW)

  14. The price elasticity of demand for heroin: Matched longitudinal and experimental evidence.

    PubMed

    Olmstead, Todd A; Alessi, Sheila M; Kline, Brendan; Pacula, Rosalie Liccardo; Petry, Nancy M

    2015-05-01

    This paper reports estimates of the price elasticity of demand for heroin based on a newly constructed dataset. The dataset has two matched components concerning the same sample of regular heroin users: longitudinal information about real-world heroin demand (actual price and actual quantity at daily intervals for each heroin user in the sample) and experimental information about laboratory heroin demand (elicited by presenting the same heroin users with scenarios in a laboratory setting). Two empirical strategies are used to estimate the price elasticity of demand for heroin. The first strategy exploits the idiosyncratic variation in the price experienced by a heroin user over time that occurs in markets for illegal drugs. The second strategy exploits the experimentally induced variation in price experienced by a heroin user across experimental scenarios. Both empirical strategies result in the estimate that the conditional price elasticity of demand for heroin is approximately -0.80.

  15. The price elasticity of demand for heroin: matched longitudinal and experimental evidence#

    PubMed Central

    Olmstead, Todd A.; Alessi, Sheila M.; Kline, Brendan; Pacula, Rosalie Liccardo; Petry, Nancy M.

    2015-01-01

    This paper reports estimates of the price elasticity of demand for heroin based on a newly constructed dataset. The dataset has two matched components concerning the same sample of regular heroin users: longitudinal information about real-world heroin demand (actual price and actual quantity at daily intervals for each heroin user in the sample) and experimental information about laboratory heroin demand (elicited by presenting the same heroin users with scenarios in a laboratory setting). Two empirical strategies are used to estimate the price elasticity of demand for heroin. The first strategy exploits the idiosyncratic variation in the price experienced by a heroin user over time that occurs in markets for illegal drugs. The second strategy exploits the experimentally-induced variation in price experienced by a heroin user across experimental scenarios. Both empirical strategies result in the estimate that the conditional price elasticity of demand for heroin is approximately −0.80. PMID:25702687

  16. Dose and elasticity of demand for self-administered cocaine in rats.

    PubMed

    Kearns, David N; Silberberg, Alan

    2016-04-01

    The present experiment tested whether the elasticity of demand for self-administered cocaine in rats is dose-dependent. Subjects lever pressed for three different doses of intravenous cocaine - 0.11, 0.33, and 1.0 mg/kg/infusion - on a demand procedure where the number of lever presses required per infusion increased within a session. The main finding was that demand for the 0.11 mg/kg dose was more elastic than it was for the two larger doses. There was no difference in demand elasticity between the 0.33 and 1.0 mg/kg doses. These results parallel findings previously reported in monkeys. The present study also demonstrated that a within-session procedure can be used to generate reliable demand curves.

  17. An Airline-Based Multilevel Analysis of Airfare Elasticity for Passenger Demand

    NASA Technical Reports Server (NTRS)

    Castelli, Lorenzo; Ukovich, Walter; Pesenti, Raffaele

    2003-01-01

    Price elasticity of passenger demand for a specific airline is estimated. The main drivers affecting passenger demand for air transportation are identified. First, an Ordinary Least Squares regression analysis is performed. Then, a multilevel analysis-based methodology to investigate the pattern of variation of price elasticity of demand among the various routes of the airline under study is proposed. The experienced daily passenger demands on each fare-class are grouped for each considered route. 9 routes were studied for the months of February and May in years from 1999 to 2002, and two fare-classes were defined (business and economy). The analysis has revealed that the airfare elasticity of passenger demand significantly varies among the different routes of the airline.

  18. Decomposition of the price and income elasticities of the consumer demand for gasoline

    SciTech Connect

    Archibald, R.; Gillingham, R.

    1981-04-01

    The authors specify and estimate a model of the short-run demand for gasoline which allows them to decompose a consumer's gasoline demand elasticities into miles-driven and driving-efficiency components. Their model is estimated using detailed household survey data which allows direct focus on the short run, holding both the household's automobile stock and demographic profile fixed. Among the most interesting results are: (1) The data allow interesting insights to be drawn into the interrelationship between these important variables and household behavior with respect to gasoline consumption, miles driven, and driving efficiency. (2) The gasoline demand behavior of one-car and multi-car households differ significantly from each other. Evaluated at overall sample means, one-car households have higher (in absolute value) price elasticites for gasoline, miles driven and fuel-efficiency demand. Conversely, multi-car households have higher (in absolute value) total expenditure elasticities for each category. (3) For both one-car and multi-car households, roughly 75% of the estimated price elasticity and roughly 80% of the estimated total-expenditure elasticity of gasoline demand stem from the miles-driven component. The estimated fuel-efficiency elasticities, though smaller than their standard errors, indicate that households respond to changes in prices and total-expenditure levels not only by changing the number of miles they drive, but also by changing the efficiency with which they drive them. 23 references, 3 tables.

  19. [Price elasticity of demand for cigarettes and alcohol in Ecuador, based on household data].

    PubMed

    Chávez, Ricardo

    2016-10-01

    Estimate price elasticity of demand for cigarettes and alcohol in Ecuador using cross-sectional data from the National Survey of Urban and Rural Household Income and Expenditures (ENIGHUR is the acronym in Spanish) 2011-2012. ENIGHUR 2011-2012 data were used with Deaton's (1, 2) methodology to estimate price elasticity of demand for cigarettes and alcohol with expenditure and quantity information. Household socioeconomic variables were also included. Price elasticity of demand for cigarettes is -0.87, meaning that a 10% price increase could lead to an 8.7% decrease in consumption. Results for cross-price elasticities of alcohol on cigarette demand are negative, as expected, indicating that they are complementary goods; however, the results are not statistically significant. Furthermore, it was found that price elasticity of demand for alcohol is -0.44, meaning that a 10% increase in the price of alcohol would produce a 4.4% decrease in consumption. A policy of price increases, for example, with a tax increase, applied to both cigarettes and alcohol, could have a positive effect on public health through reductions in consumption of both goods. However, this measure would not be sufficient to bridge gaps in prevalence measures and health outcomes between sex and other population groups, given the observed difference in the sensitivity of consumption to price variations.

  20. New estimates of elasticity of demand for healthcare in rural China.

    PubMed

    Zhou, Zhongliang; Su, Yanfang; Gao, Jianmin; Xu, Ling; Zhang, Yaoguang

    2011-12-01

    Only limited empirical studies reported own-price elasticity of demand for health care in rural China. Neither research on income elasticity of demand for health care nor cross-price elasticity of demand for inpatient versus outpatient services in rural China has been reported. However, elasticity of demand is informative to evaluate current policy and to guide further policy making. Our study contributes to the literature by estimating three elasticities (i.e., own-price elasticity, cross-price elasticity, and income elasticity of demand for health care based on nationwide-representative data. We aim to answer three empirical questions with regard to health expenditure in rural China: (1) Which service is more sensitive to price change, outpatient or inpatient service? (2) Is outpatient service a substitute or complement to inpatient service? and (3) Does demand for inpatient services grow faster than demand for outpatient services with income growth? Based on data from a National Health Services Survey, a Probit regression model with probability of outpatient visit and probability of inpatient visit as dependent variables and a zero-truncated negative binomial regression model with outpatient visits as dependent variable were constructed to isolate the effects of price and income on demand for health care. Both pooled and separated regressions for 2003 and 2008 were conducted with tests of robustness. Own-price elasticities of demand for first outpatient visit, outpatient visits among users and first inpatient visit are -0.519 [95% confidence interval (-0.703, -0.336)], -0.547 [95% confidence interval (-0.747, -0.347)] and -0.372 [95% confidence interval (-0.517, -0.226)], respectively. Cross-price elasticities of demand for first outpatient visit, outpatient visits among users and first inpatient visit are 0.073 [95% confidence interval (-0.176, 0.322)], 0.308 [95% confidence interval (0.087, 0.528)], and 0.059 [95% confidence interval (-0.085, 0

  1. Revisiting Marshall's Third Law: Why Does Labor's Share Interact with the Elasticity of Substitution to Decrease the Elasticity of Labor Demand?

    ERIC Educational Resources Information Center

    Hoffman, Saul D.

    2009-01-01

    The third Marshall-Hicks-Allen rule of elasticity of derived demand purports to show that labor demand is less elastic when labor is a smaller share of total costs. As Hicks, Allen, and then Bronfenbrenner showed, this rule is not quite correct, and actually is complicated by an unexpected negative relationship involving labor's share of total…

  2. Differences in price elasticities of demand for health insurance: a systematic review.

    PubMed

    Pendzialek, Jonas B; Simic, Dusan; Stock, Stephanie

    2016-01-01

    Many health insurance systems apply managed competition principles to control costs and quality of health care. Besides other factors, managed competition relies on a sufficient price-elastic demand. This paper presents a systematic review of empirical studies on price elasticity of demand for health insurance. The objective was to identify the differing international ranges of price elasticity and to find socio-economic as well as setting-oriented factors that influence price elasticity. Relevant literature for the topic was identified through a two-step identification process including a systematic search in appropriate databases and further searches within the references of the results. A total of 45 studies from countries such as the USA, Germany, the Netherlands, and Switzerland were found. Clear differences in price elasticity by countries were identified. While empirical studies showed a range between -0.2 and -1.0 for optional primary health insurance in the US, higher price elasticities between -0.6 and -4.2 for Germany and around -2 for Switzerland were calculated for mandatory primary health insurance. Dutch studies found price elasticities below -0.5. In consideration of all relevant studies, age and poorer health status were identified to decrease price elasticity. Other socio-economic factors had an unclear impact or too limited evidence. Premium level, range of premiums, homogeneity of benefits/coverage and degree of forced decision were found to have a major influence on price elasticity in their settings. Further influence was found from supplementary insurance and premium-dependent employer contribution.

  3. Price Elasticity of Demand: An A-Level Economics Revision Exercise.

    ERIC Educational Resources Information Center

    Williams, Paul

    1992-01-01

    Presents a review exercise requiring students to sort diagrams and descriptions of price elasticity of demand. Reports that students are given jumbled diagrams and explanations that they must arrange in proper form. Reveals that some items are designed as distractors. (SG)

  4. Price Elasticity of Demand: An A-Level Economics Revision Exercise.

    ERIC Educational Resources Information Center

    Williams, Paul

    1992-01-01

    Presents a review exercise requiring students to sort diagrams and descriptions of price elasticity of demand. Reports that students are given jumbled diagrams and explanations that they must arrange in proper form. Reveals that some items are designed as distractors. (SG)

  5. Economic analysis of the water demand in the hotels and restaurants sector: Shadow prices and elasticities

    NASA Astrophysics Data System (ADS)

    Angulo, Ana; Atwi, Majed; Barberán, Ramón; Mur, Jesús

    2014-08-01

    Despite the growing economic importance of tourism, and its impact on relative water shortage, little is known about the role that water plays in the productive process of hotels and restaurants and, therefore, the possible implications of water demand management policy for this sector. This study aims to fill this gap. It is based on the microdata of 676 firms in the sector, operating in the city of Zaragoza (Spain) for a 12 year period. Based on the Translog cost function, we estimate the shadow price of water in the short run and, from a long-run perspective, its direct price elasticity, its cross elasticities relative to labor, capital, and supplies, and its elasticity with respect to the level of output. The results obtained show that water provides sector firms returns that are on average higher than its price, although in the case of hotels the margin is really narrow. This situation provides policy makers with a margin for applying price increases without affecting the sector's viability, with some caution in the case of hotels. Water demand elasticity equals -0.38 in the case of hotels, but it is not significant in the case of restaurants and bar-cafes; hence, only in hotels is there potential for influencing water use patterns, encouraging the resource's conservation through pricing policy. Moreover, capital is a substitutive factor of water, and the elasticity of water with respect to output is 0.40, all of which should also be considered by policy makers in water resource management.

  6. Does subsidy work? Price elasticity of demand for influenza vaccination among the elderly in Japan.

    PubMed

    Kondo, Masahide; Hoshi, Shu-ling; Okubo, Ichiro

    2009-08-01

    Subsidy for influenza vaccination is often provided to the elderly in order to encourage them to receive a flu shot in developed countries. However, its effect on uptake rate, i.e., price elasticity of demand, has not been well studied. Japan's decentralised vaccination programme allows observation of various pairs in price and uptake rate of flu shots among the elderly by the municipality from 2001/2002 to 2004/2005 season. We combine our sample survey data (n=281), which monitor price, subsidy and uptake rate, with published data on local characteristics in order to estimate price elasticity of demand with panel model. We find price elasticity of demand for influenza vaccine: nearly zero in nationwide, nearly zero in urban area, and -1.07 in rural area. The results question the rationale for subsidy, especially in urban area. There are cases where maintaining or increasing the level of subsidy is not an efficient allocation of finite health care resources. When organising a vaccination programme, health manager should be careful about the balance between subsidy and other efforts in order to encourage the elderly to receive shots with price elasticity in mind.

  7. Estimating Demand and Cross-Price Elasticity for Very Low Nicotine Content (VLNC) Cigarettes Using a Simulated Demand Task.

    PubMed

    Tucker, Megan R; Laugesen, Murray; Grace, Randolph C

    2017-03-03

    Very Low Nicotine Content (VLNC) cigarettes might be useful as part of a tobacco control strategy, but relatively little is known about their acceptability as substitutes for regular cigarettes. We compared subjective effects and demand for regular cigarettes and Very Low Nicotine Content (VLNC) cigarettes, and estimated cross-price elasticity for VLNC cigarettes, using simulated demand tasks. 40 New Zealand smokers sampled a VLNC cigarette and completed Cigarette Purchase Tasks to indicate their demand for regular cigarettes and VLNC cigarettes at a range of prices, and a cross-price task indicating how many regular cigarettes and VLNC cigarettes they would purchase at 0.5x, 1x, and 2x the current market price for regular cigarettes, assuming the price of VLNC cigarettes remained constant. They also rated the subjective effects of the VLNC cigarette and their usual-brand regular cigarettes. Cross-price elasticity for VLNC cigarettes was estimated as 0.24 and was significantly positive, indicating that VLNC cigarettes are partially substitutable for regular cigarettes. VLNC cigarettes were rated as less satisfying and psychologically rewarding than regular cigarettes, but this was unrelated to demand or substitutability. VLNC cigarettes are potentially substitutable for regular cigarettes. Their availability may reduce tobacco consumption, nicotine intake and addiction; making it easier for smokers to quit. VLNC cigarettes share the behavioural and sensory components of smoking whilst delivering negligible levels of nicotine. Although smokers rated VLNCs as less satisfying than regular cigarettes, smokers said they would increase their consumption of VLNCs as the price of regular cigarettes increased, if VLNCs were available at a lower price. This suggests that VLNCs are partially substitutable for regular cigarettes. VLNCs can be part of an effective tobacco control strategy, by reducing nicotine dependence and improving health and financial outcomes for smokers.

  8. Empirical analysis of the spot market implications ofprice-elastic demand

    SciTech Connect

    Siddiqui, Afzal S.; Bartholomew, Emily S.; Marnay, Chris

    2004-07-08

    Regardless of the form of restructuring, deregulated electricity industries share one common feature: the absence of any significant, rapid demand-side response to the wholesale (or, spotmarket) price. For a variety of reasons, electricity industries continue to charge most consumers an average cost based on regulated retail tariff from the era of vertical integration, even as the retailers themselves are forced to purchase electricity at volatile wholesale prices set in open markets. This results in considerable price risk for retailers, who are sometimes forbidden by regulators from signing hedging contracts. More importantly, because end-users do not perceive real-time (or even hourly or daily) fluctuations in the wholesale price of electricity, they have no incentive to adjust their consumption in response to price signals. Consequently, demand for electricity is highly inelastic, and electricity generation resources can be stretched to the point where system stability is threatened. This, then, facilitates many other problems associated with electricity markets, such as market power and price volatility. Indeed, economic theory suggests that even modestly price-responsive demand can remove the stress on generation resources and decrease spot prices. To test this theory, we use actual generator bid data from the New York control area to construct supply stacks, and intersect them with demand curves of various slopes to approximate different levels of demand elasticity. We then estimate the potential impact of real-time pricing on the equilibrium spot price and quantity. These results indicate the immediate benefits that could be derived from a more price-elastic demand. Such analysis can provide policymakers with a measure of how effective price-elastic demand can potentially reduce prices and maintain consumption within the capability of generation resources.

  9. Price elasticity of demand for malt liquor beer: findings from a US pilot study.

    PubMed

    French, Michael Thomas; Browntaylor, Didra; Bluthenthal, Ricky Neville

    2006-05-01

    Our objective is to estimate the relative price elasticity of demand for malt liquor beer (MLB), regular beer, hard liquor, and a combined group of all other alcoholic beverages. Three hundred and twenty-nine alcohol consumers (mostly male) in South-Central Los Angeles answered a series of questions pertaining to expected consumption responses to hypothetical price increases. We found that based on a 10% price increase, the mean price elasticity of demand (% change in quantity demanded / % change in price) was -0.79 for MLB drinkers, -1.14 for regular beer drinkers, -1.11 for hard liquor drinkers, and -1.69 for the combined group of all other drinkers. Logistic regression analysis revealed that the personal characteristics significantly related to being a MLB drinker were older age, not working, being homeless, and a daily drinker. Daily (or nearly daily) drinkers were more likely to be married, earning lower incomes, and hard liquor drinkers. This study is the first to investigate the price elasticity of demand for MLB drinkers and other heavy alcohol consumers in poor urban neighborhoods of the US. Future research can use the methods from this pilot study to more rigorously examine and compare the price sensitivity among heavy drinking groups.

  10. A rational approach to estimating the surgical demand elasticity needed to guide manpower reallocation during contagious outbreaks.

    PubMed

    Tsao, Hsiao-Mei; Sun, Ying-Chou; Liou, Der-Ming

    2015-01-01

    Emerging infectious diseases continue to pose serious threats to global public health. So far, however, few published study has addressed the need for manpower reallocation needed in hospitals when such a serious contagious outbreak occurs. To quantify the demand elasticity of the major surgery types in order to guide future manpower reallocation during contagious outbreaks. Based on a nationwide research database in Taiwan, we extracted the monthly volumes of major surgery types for the period 1998-2003, which covered the SARS period, in order to carry out a time series analysis. The demand elasticity of each surgery type was then estimated by autoregressive integrated moving average (ARIMA) analysis. During the study period, the surgical volumes of most selected surgery types either increased or remained steady. We categorized these surgery types into low-, moderate- and high-elastic groups according to their demand elasticity. Appendectomy, 'open reduction of fracture with internal fixation' and 'free skin graft' were in the low demand elasticity group. Transurethral prostatectomy and extracorporeal shockwave lithotripsy (ESWL) were in the high demand elasticity group. The manpower of the departments carrying out the surgeries with low demand elasticity should be maintained during outbreaks. In contrast, departments in charge of surgeries mainly with high demand elasticity, like urology departments, may be in a position to have part of their staff reallocated. Taking advantage of the demand variation during the SARS period in 2003, we adopted the concept of demand elasticity and used a time series approach to figure out an effective index of demand elasticity for various types of surgery that could be used as a rational reference to carry out manpower reallocation during contagious outbreak situations.

  11. Price and income elasticities of energy demand: Some estimates for Kuwait using two econometric models

    SciTech Connect

    Al-Mutairi, N.H.; Eltony, M.N.

    1995-12-31

    This paper estimates the demand for energy in Kuwait for the period 1965-1989 using two econometric models: a cointegration and error correction model (ECM) and a simultaneous-equation model (SEM). The results obtained from both models are similar. It is found that the energy demand is inelastic with respect to price in the short and long run, and while it is elastic in the long run, the energy demand is inelastic with respect to income in the short run. Both models` validation shows that the ECM performed better in replicating the past than the simultaneous model, suggesting the need to use the ECM to identify future prospects for energy demand in Kuwait.

  12. Price elasticity of on- and off-premises demand for alcoholic drinks: A Tobit analysis.

    PubMed

    Jiang, Heng; Livingston, Michael; Room, Robin; Callinan, Sarah

    2016-06-01

    Understanding how price policies will affect alcohol consumption requires estimates of the impact of price on consumption among different types of drinkers and across different consumption settings. This study aims to estimate how changes in price could affect alcohol demand across different beverages, different settings (on-premise, e.g., bars, restaurants and off-premise, e.g., liquor stores, supermarkets), and different levels of drinking and income. Tobit analysis is employed to estimate own- and cross-price elasticities of alcohol demand among 11 subcategories of beverage based on beverage type and on- or off-premise supply, using cross-sectional data from the Australian arm of the International Alcohol Control Survey 2013. Further elasticity estimates were derived for sub-groups of drinkers based on their drinking and income levels. The results suggest that demand for nearly every subcategory of alcohol significantly responds to its own price change, except for on-premise spirits and ready-to-drink spirits. The estimated demand for off-premise beverages is more strongly affected by own price changes than the same beverages in on-premise settings. Demand for off-premise regular beer and off-premise cask wine is more price responsive than demand for other beverages. Harmful drinkers and lower income groups appear more price responsive than moderate drinkers and higher income groups. Our findings suggest that alcohol price policies, such as increasing alcohol taxes or introducing a minimum unit price, can reduce alcohol demand. Price appears to be particularly effective for reducing consumption and as well as alcohol-related harm among harmful drinkers and lower income drinkers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Economics of tobacco control in Pakistan: estimating elasticities of cigarette demand.

    PubMed

    Mushtaq, Nasir; Mushtaq, Saghir; Beebe, Laura A

    2011-11-01

    Despite ongoing global efforts for tobacco control, low-income countries with struggling economies have challenges to effectively implement tobacco policies and programs. Due to the complexity of the tobacco control issue and lack of comprehensive policies, tobacco use is increasing in Pakistan. The aim of this study was to assess the effect of taxes on tobacco demand in Pakistan. Various surveillance indicators of tobacco use were assessed from 2001 to 2009. Price elasticities of cigarette demand in Pakistan were investigated. During 2003-2009, annual per capita cigarette consumption increased by 30%. Analysis of economic data indicated that a 10% increase in cigarette prices would lead to 4.8% decrease in cigarette consumption while controlling for per capita income in the short term. The long-term price elasticities of cigarette demand were estimated at -1.17. The estimations provided support for myopic addiction model for cigarette consumption in Pakistan. Increasing tobacco taxes would have a significant impact on tobacco consumption in Pakistan. Cigarette consumption could decrease by 11.7% in the long term if there was a 10% increase in its price. The results of this study should benefit policymakers as it provides information on the characteristics of the cigarette consumption and cigarette demand function that may help in planning tobacco control strategies in low-income and middle-income countries.

  14. What U.S. data should be used to measure the price elasticity of demand for alcohol?

    PubMed

    Ruhm, Christopher J; Jones, Alison Snow; McGeary, Kerry Anne; Kerr, William C; Terza, Joseph V; Greenfield, Thomas K; Pandian, Ravi S

    2012-12-01

    This paper examines how estimates of the price elasticity of demand for beer vary with the choice of alcohol price series examined. Our most important finding is that the commonly used ACCRA price data are unlikely to reliably indicate alcohol demand elasticities-estimates obtained from this source vary drastically and unpredictably. As an alternative, researchers often use beer taxes to proxy for alcohol prices. While the estimated beer taxes elasticities are more stable, there are several problems with using taxes, including difficulties in accounting for cross-price effects. We believe that the most useful estimates reported in this paper are obtained using annual Uniform Product Code (UPC) "barcode" scanner data on grocery store alcohol prices. These estimates suggest relatively low demand elasticity, probably around -0.3, with evidence that the elasticities are considerably overstated in models that control for beer but not wine or spirits prices.

  15. China's medical savings accounts: an analysis of the price elasticity of demand for health care.

    PubMed

    Yu, Hao

    2016-09-20

    Although medical savings accounts (MSAs) have drawn intensive attention across the world for their potential in cost control, there is limited evidence of their impact on the demand for health care. This paper is intended to fill that gap. First, we built up a dynamic model of a consumer's problem of utility maximization in the presence of a nonlinear price schedule embedded in an MSA. Second, the model was implemented using data from a 2-year MSA pilot program in China. The estimated price elasticity under MSAs was between -0.42 and -0.58, i.e., higher than that reported in the literature. The relatively high price elasticity suggests that MSAs as an insurance feature may help control costs. However, the long-term effect of MSAs on health costs is subject to further analysis.

  16. Predictors of the nicotine reinforcement threshold, compensation, and elasticity of demand in a rodent model of nicotine reduction policy*

    PubMed Central

    Grebenstein, Patricia E.; Burroughs, Danielle; Roiko, Samuel A.; Pentel, Paul R.; LeSage, Mark G.

    2015-01-01

    Background The FDA is considering reducing the nicotine content in tobacco products as a population-based strategy to reduce tobacco addiction. Research is needed to determine the threshold level of nicotine needed to maintain smoking and the extent of compensatory smoking that could occur during nicotine reduction. Sources of variability in these measures across sub-populations also need to be identified so that policies can take into account the risks and benefits of nicotine reduction in vulnerable populations. Methods The present study examined these issues in a rodent nicotine self- administration model of nicotine reduction policy to characterize individual differences in nicotine reinforcement thresholds, degree of compensation, and elasticity of demand during progressive reduction of the unit nicotine dose. The ability of individual differences in baseline nicotine intake and nicotine pharmacokinetics to predict responses to dose reduction was also examined. Results Considerable variability in the reinforcement threshold, compensation, and elasticity of demand was evident. High baseline nicotine intake was not correlated with the reinforcement threshold, but predicted less compensation and less elastic demand. Higher nicotine clearance predicted low reinforcement thresholds, greater compensation, and less elastic demand. Less elastic demand also predicted lower reinforcement thresholds. Conclusions These findings suggest that baseline nicotine intake, nicotine clearance, and the essential value of nicotine (i.e. elasticity of demand) moderate the effects of progressive nicotine reduction in rats and warrant further study in humans. They also suggest that smokers with fast nicotine metabolism may be more vulnerable to the risks of nicotine reduction. PMID:25891231

  17. An Analysis of the Price Elasticity of Demand for Household Appliances

    SciTech Connect

    Fujita, Kimberly; Dale, Larry; Fujita, K. Sydny

    2008-01-25

    This report summarizes our study of the price elasticity of demand for home appliances, including refrigerators, clothes washers, and dishwashers. In the context of increasingly stringent appliance standards, we are interested in what kind of impact the increased manufacturing costs caused by higher efficiency requirements will have on appliance sales. We begin with a review of existing economics literature describing the impact of economic variables on the sale of durable goods.We then describe the market for home appliances and changes in this market over the past 20 years, performing regression analysis on the shipments of home appliances and relevant economic variables including changes to operating cost and household income. Based on our analysis, we conclude that the demand for home appliances is price inelastic.

  18. A static predictor of seismic demand on frames based on a post-elastic deflected shape

    USGS Publications Warehouse

    Mori, Y.; Yamanaka, T.; Luco, N.; Cornell, C.A.

    2006-01-01

    Predictors of seismic structural demands (such as inter-storey drift angles) that are less time-consuming than nonlinear dynamic analysis have proven useful for structural performance assessment and for design. Luco and Cornell previously proposed a simple predictor that extends the idea of modal superposition (of the first two modes) with the square-root-of-sum-of-squares (SRSS) rule by taking a first-mode inelastic spectral displacement into account. This predictor achieved a significant improvement over simply using the response of an elastic oscillator; however, it cannot capture well large displacements caused by local yielding. A possible improvement of Luco's predictor is discussed in this paper, where it is proposed to consider three enhancements: (i) a post-elastic first-mode shape approximated by the deflected shape from a nonlinear static pushover analysis (NSPA) at the step corresponding to the maximum drift of an equivalent inelastic single-degree-of-freedom (SDOF) system, (ii) a trilinear backbone curve for the SDOF system, and (iii) the elastic third-mode response for long-period buildings. Numerical examples demonstrate that the proposed predictor is less biased and results in less dispersion than Luco's original predictor. Copyright ?? 2006 John Wiley & Sons, Ltd.

  19. What U.S. Data Should be Used to Measure the Price Elasticity of Demand for Alcohol?*

    PubMed Central

    Ruhm, Christopher J.; Jones, Alison Snow; McGeary, Kerry Anne; Kerr, William C.; Terza, Joseph V.; Greenfield, Thomas K.; Pandian, Ravi S.

    2012-01-01

    This paper examines how estimates of the price elasticity of demand for beer vary with the choice of alcohol price series examined. Our most important finding is that the commonly used ACCRA price data are unlikely to reliably indicate alcohol demand elasticities—estimates obtained from this source vary drastically and unpredictably. As an alternative, researchers often use beer taxes to proxy for alcohol prices. While the estimated beer taxes elasticities are more stable, there are several problems with using taxes, including difficulties in accounting for cross-price effects. We believe that the most useful estimates reported in this paper are obtained using annual Uniform Product Code (UPC) “barcode” scanner data on grocery store alcohol prices. These estimates suggest relatively low demand elasticity, probably around −0.3, with evidence that the elasticities are considerably overstated in models that control for beer but not wine or spirits prices. PMID:23022631

  20. Estimating cross-price elasticity of e-cigarettes using a simulated demand procedure.

    PubMed

    Grace, Randolph C; Kivell, Bronwyn M; Laugesen, Murray

    2015-05-01

    Our goal was to measure the cross-price elasticity of electronic cigarettes (e-cigarettes) and simulated demand for tobacco cigarettes both in the presence and absence of e-cigarette availability. A sample of New Zealand smokers (N = 210) completed a Cigarette Purchase Task to indicate their demand for tobacco at a range of prices. They sampled an e-cigarette and rated it and their own-brand tobacco for favorability, and indicated how many e-cigarettes and regular cigarettes they would purchase at 0.5×, 1×, and 2× the current market price for regular cigarettes, assuming that the price of e-cigarettes remained constant. Cross-price elasticity for e-cigarettes was estimated as 0.16, and was significantly positive, indicating that e-cigarettes were partially substitutable for regular cigarettes. Simulated demand for regular cigarettes at current market prices decreased by 42.8% when e-cigarettes were available, and e-cigarettes were rated 81% as favorably as own-brand tobacco. However when cigarettes cost 2× the current market price, significantly more smokers said they would quit (50.2%) if e-cigarettes were not available than if they were available (30.0%). Results show that e-cigarettes are potentially substitutable for regular cigarettes and their availability will reduce tobacco consumption. However, e-cigarettes may discourage smokers from quitting entirely as cigarette price increases, so policy makers should consider maintaining a constant relative price differential between e-cigarettes and tobacco cigarettes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Estimating the own-price elasticity of demand for irrigation water in the Musi catchment of India

    NASA Astrophysics Data System (ADS)

    Davidson, Brian; Hellegers, Petra

    2011-10-01

    SummaryAs irrigation water is an input into a production process, its demand must be 'derived'. According to theory, a derived demand schedule should be downward sloping and dependent on the outputs produced from it, the prices of other inputs and the price of the water itself. Problems arise when an attempt is made to estimate the demand for irrigation water and the resulting own-price elasticity of demand, as the uses to which water is put are spatially, temporarily and geographically diverse. Because water is not generally freely traded, what normally passes for an estimate of the own-price elasticity of demand for irrigation water is usually a well argued assumption or an estimate that is derived from a simulation model of a hypothesized producer. Such approaches tend to provide an inadequate explanation of what is an extremely complex and important relationship. An adequate explanation of the relationship between the price and the quantity demanded of water should be one that not only accords with the theoretical expectations, but also accounts for the diversity of products produced from water (which includes the management practices of farmers), the seasons in which it is used and over the region within which it is used. The objective in this article is to present a method of estimating the demand curve for irrigation water. The method uses actual field data which is collated using the Residual Method to determine the value of the marginal product of water deployed over a wide range of crops, seasons and regions. These values of the marginal products, all which must lie of the input demand schedule for water, are then ordered from the highest value to the lowest. Then, the amount of irrigation water used for each product, in each season and in each region is cumulatively summed over the range of uses according to the order of the values of the marginal products. This data, once ordered, is then used to econometrically estimate the demand schedule from which

  2. Estimating residential price elasticity of demand for water: A contingent valuation approach

    NASA Astrophysics Data System (ADS)

    Thomas, John F.; Syme, Geoffrey J.

    1988-11-01

    Residential households in Perth, Western Australia have access to privately extracted groundwater as well as a public mains water supply, which has been charged through a two-part block tariff. A contingent valuation approach is developed to estimate price elasticity of demand for public supply. Results are compared with those of a multivariate time series analysis. Validation tests for the contingent approach are proposed, based on a comparison of predicted behaviors following hypothesised price changes with relevant independent data. Properly conducted, the contingent approach appears to be reliable, applicable where the available data do not favor regression analysis, and a fruitful source of information about social, technical, and behavioral responses to change in the price of water.

  3. Understanding Heterogeneity in Price Elasticities in the Demand for Alcohol for Older Individuals

    PubMed Central

    Ayyagari, Padmaja; Deb, Partha; Fletcher, Jason; Gallo, William; Sindelar, Jody L.

    2013-01-01

    This paper estimates the price elasticity of demand for alcohol using Health and Retirement Study data. To account for unobserved heterogeneity in price responsiveness, we use finite mixture models. We recover two latent groups, one is significantly responsive to price, but the other is unresponsive. The group with greater responsiveness is disadvantaged in multiple domains, including health, financial resources, education and perhaps even planning abilities. These results have policy implications. The unresponsive group drinks more heavily, suggesting that a higher tax would fail to curb the negative alcohol-related externalities. In contrast, the more disadvantaged group is more responsive to price, thus suffering greater deadweight loss, yet this group consumes fewer drinks per day and might be less likely to impose negative externalities. PMID:22162113

  4. Understanding heterogeneity in price elasticities in the demand for alcohol for older individuals.

    PubMed

    Ayyagari, Padmaja; Deb, Partha; Fletcher, Jason; Gallo, William; Sindelar, Jody L

    2013-01-01

    This paper estimates the price elasticity of demand for alcohol using Health and Retirement Study data. To account for unobserved heterogeneity in price responsiveness, we use finite mixture models. We recover two latent groups, one is significantly responsive to price, but the other is unresponsive. The group with greater responsiveness is disadvantaged in multiple domains, including health, financial resources, education and perhaps even planning abilities. These results have policy implications. The unresponsive group drinks more heavily, suggesting that a higher tax would fail to curb the negative alcohol-related externalities. In contrast, the more disadvantaged group is more responsive to price, thus suffering greater deadweight loss, yet this group consumes fewer drinks per day and might be less likely to impose negative externalities.

  5. Price elasticity of the demand for sugar sweetened beverages and soft drinks in Mexico.

    PubMed

    Colchero, M A; Salgado, J C; Unar-Munguía, M; Hernández-Ávila, M; Rivera-Dommarco, J A

    2015-12-01

    A large and growing body of scientific evidence demonstrates that sugar drinks are harmful to health. Intake of sugar-sweetened beverages (SSB) is a risk factor for obesity and type 2 diabetes. Mexico has one of the largest per capita consumption of soft drinks worldwide and high rates of obesity and diabetes. Fiscal approaches such as taxation have been recommended as a public health policy to reduce SSB consumption. We estimated an almost ideal demand system with linear approximation for beverages and high-energy food by simultaneous equations and derived the own and cross price elasticities for soft drinks and for all SSB (soft drinks, fruit juices, fruit drinks, flavored water and energy drinks). Models were stratified by income quintile and marginality index at the municipality level. Price elasticity for soft drinks was -1.06 and -1.16 for SSB, i.e., a 10% price increase was associated with a decrease in quantity consumed of soft drinks by 10.6% and 11.6% for SSB. A price increase in soft drinks is associated with larger quantity consumed of water, milk, snacks and sugar and a decrease in the consumption of other SSB, candies and traditional snacks. The same was found for SSB except that an increase in price of SSB was associated with a decrease in snacks. Higher elasticities were found among households living in rural areas (for soft drinks), in more marginalized areas and with lower income. Implementation of a tax to soft drinks or to SSB could decrease consumption particularly among the poor. Substitutions and complementarities with other food and beverages should be evaluated to assess the potential impact on total calories consumed.

  6. Predictors of the nicotine reinforcement threshold, compensation, and elasticity of demand in a rodent model of nicotine reduction policy.

    PubMed

    Grebenstein, Patricia E; Burroughs, Danielle; Roiko, Samuel A; Pentel, Paul R; LeSage, Mark G

    2015-06-01

    The FDA is considering reducing the nicotine content in tobacco products as a population-based strategy to reduce tobacco addiction. Research is needed to determine the threshold level of nicotine needed to maintain smoking and the extent of compensatory smoking that could occur during nicotine reduction. Sources of variability in these measures across sub-populations also need to be identified so that policies can take into account the risks and benefits of nicotine reduction in vulnerable populations. The present study examined these issues in a rodent nicotine self-administration model of nicotine reduction policy to characterize individual differences in nicotine reinforcement thresholds, degree of compensation, and elasticity of demand during progressive reduction of the unit nicotine dose. The ability of individual differences in baseline nicotine intake and nicotine pharmacokinetics to predict responses to dose reduction was also examined. Considerable variability in the reinforcement threshold, compensation, and elasticity of demand was evident. High baseline nicotine intake was not correlated with the reinforcement threshold, but predicted less compensation and less elastic demand. Higher nicotine clearance predicted low reinforcement thresholds, greater compensation, and less elastic demand. Less elastic demand also predicted lower reinforcement thresholds. These findings suggest that baseline nicotine intake, nicotine clearance, and the essential value of nicotine (i.e. elasticity of demand) moderate the effects of progressive nicotine reduction in rats and warrant further study in humans. They also suggest that smokers with fast nicotine metabolism may be more vulnerable to the risks of nicotine reduction. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Price elasticity of demand for psychiatric consultation in a Nigerian psychiatric service.

    PubMed

    Esan, Oluyomi

    2016-12-01

    This paper addresses price elasticity of demand (PED) in a region where most patients make payments for consultations out of pocket. PED is a measure of the responsiveness of the quantity demanded of goods or services to changes in price. The study was done in the context of an outpatient psychiatric clinic in a sub -Saharan African country. The study was performed at the University College Hospital (UCH), Ibadan, Nigeria. Aggregate data were collected on weekly clinic attendance over a 24-month period October 2008 - September 2010 representing 12 months before, to 12months after a 67% increase in price of outpatient psychiatric consultation. The average weekly clinic attendance prior to the increase was compared to the average clinic attendance after the price increase. Arc-PED for consultation was also estimated. Clinic attendance dropped immediately and significantly in the weeks following the price increase. There was a 34.4% reduction in average weekly clinic attendance. Arc-PED for psychiatric consultation was -0.85. In comparison to reported PED on health care goods and services, this study finds a relatively high PED in psychiatric consultation following an increase in price of user fees of psychiatric consultation.

  8. Price elasticity of the demand for soft drinks, other sugar-sweetened beverages and energy dense food in Chile.

    PubMed

    Guerrero-López, Carlos M; Unar-Munguía, Mishel; Colchero, M Arantxa

    2017-02-10

    Chile is the second world's largest per capita consumer of caloric beverages. Caloric beverages are associated with overweight, obesity and other chronic diseases. The objective of this study is to estimate the price elasticity of demand for soft drinks, other sugar-sweetened beverages and high-energy dense foods in urban areas in Chile in order to evaluate the potential response of households' consumption to changes in prices. We used microdata from the VII Family Budget Survey 2012-2013, which collects information on expenditures made by Chilean urban households on items such as beverages and foods. We estimated a Linear Approximation of an Almost Ideal Demand System Model to derive own and cross price elasticities of milk, coffee, tea and other infusions, plain water, soft drinks, other flavored beverages, sweet snacks, sugar and honey, and desserts. We considered the censored nature of the data and included the Inverse Mills Ratio in each equation of the demand system. We estimated a Quadratic Almost Ideal Demand System and a two-part model as sensitivity analysis. We found an own price-elasticity of -1.37 for soft drinks. This implies that a price increase of 10% is associated with a reduction in consumption of 13.7%. We found that the rest of food and beverages included in the demand system behave as substitutes for soft drinks. For instance, plain water showed a cross-price elasticity of 0.63: a 10% increase in price of soft drinks could lead to an increase of 6.3% of plain water. Own and cross price elasticities were similar between models. The demand of soft drinks is price sensitive among Chilean households. An incentive system such as subsidies to non-sweetened beverages and tax to soft drinks could lead to increases in the substitutions for other healthier beverages.

  9. Monetary Policy Rules, Supply Shocks, and the Price-Level Elasticity of Aggregate Demand: A Graphical Examination.

    ERIC Educational Resources Information Center

    Kyer, Ben L.; Maggs, Gary E.

    1995-01-01

    Utilizes two-dimensional price and output graphs to demonstrate the way that the price-level elasticity of aggregate demand affects alternative monetary policy rules designed to cope with random aggregate supply shocks. Includes graphs illustrating price-level, real Gross Domestic Product (GDP), nominal GDP, and nominal money supply targeting.…

  10. Monetary Policy Rules, Supply Shocks, and the Price-Level Elasticity of Aggregate Demand: A Graphical Examination.

    ERIC Educational Resources Information Center

    Kyer, Ben L.; Maggs, Gary E.

    1995-01-01

    Utilizes two-dimensional price and output graphs to demonstrate the way that the price-level elasticity of aggregate demand affects alternative monetary policy rules designed to cope with random aggregate supply shocks. Includes graphs illustrating price-level, real Gross Domestic Product (GDP), nominal GDP, and nominal money supply targeting.…

  11. The impact of food prices on consumption: a systematic review of research on the price elasticity of demand for food.

    PubMed

    Andreyeva, Tatiana; Long, Michael W; Brownell, Kelly D

    2010-02-01

    In light of proposals to improve diets by shifting food prices, it is important to understand how price changes affect demand for various foods. We reviewed 160 studies on the price elasticity of demand for major food categories to assess mean elasticities by food category and variations in estimates by study design. Price elasticities for foods and nonalcoholic beverages ranged from 0.27 to 0.81 (absolute values), with food away from home, soft drinks, juice, and meats being most responsive to price changes (0.7-0.8). As an example, a 10% increase in soft drink prices should reduce consumption by 8% to 10%. Studies estimating price effects on substitutions from unhealthy to healthy food and price responsiveness among at-risk populations are particularly needed.

  12. The Impact of Food Prices on Consumption: A Systematic Review of Research on the Price Elasticity of Demand for Food

    PubMed Central

    Long, Michael W.; Brownell, Kelly D.

    2010-01-01

    In light of proposals to improve diets by shifting food prices, it is important to understand how price changes affect demand for various foods. We reviewed 160 studies on the price elasticity of demand for major food categories to assess mean elasticities by food category and variations in estimates by study design. Price elasticities for foods and nonalcoholic beverages ranged from 0.27 to 0.81 (absolute values), with food away from home, soft drinks, juice, and meats being most responsive to price changes (0.7–0.8). As an example, a 10% increase in soft drink prices should reduce consumption by 8% to 10%. Studies estimating price effects on substitutions from unhealthy to healthy food and price responsiveness among at-risk populations are particularly needed. PMID:20019319

  13. Explaining the variation in elasticity estimates of gasoline demand in the United States: A meta-analysis

    SciTech Connect

    Espey, M.

    1996-12-01

    Many econometric studies of gasoline demand have been conducted over the years when fuel prices where high and concerns about energy conservation and security of supply were prominent. Studies were motivated by interest in gasoline consumers` sensitivity to fuel price changes, for the insight this might give in explaining cross country differences in gas consumption and driving and in predicting the impact of fuel tax changes on driving, fuel consumption and government revenue collections. The author used meta-analysis to determine if there are factors that systematically affect price and income elasticity estimates in studies of gasoline demand in the United States.

  14. Elasticity of Demand for Tuition Fees at an Institution of Higher Education

    ERIC Educational Resources Information Center

    Langelett, George; Chang, Kuo-Liang; Ola' Akinfenwa, Samson; Jorgensen, Nicholas; Bhattarai, Kopila

    2015-01-01

    Using a conjoint survey of 161 students at South Dakota State University (SDSU), we mapped a probability-of-enrolment curve for SDSU students, consistent with demand theory. A quasi-demand curve was created from the conditional-logit model. This study shows that along with the price of tuition fees, distance from home, availability of majors, and…

  15. Elasticity of Demand for Tuition Fees at an Institution of Higher Education

    ERIC Educational Resources Information Center

    Langelett, George; Chang, Kuo-Liang; Ola' Akinfenwa, Samson; Jorgensen, Nicholas; Bhattarai, Kopila

    2015-01-01

    Using a conjoint survey of 161 students at South Dakota State University (SDSU), we mapped a probability-of-enrolment curve for SDSU students, consistent with demand theory. A quasi-demand curve was created from the conditional-logit model. This study shows that along with the price of tuition fees, distance from home, availability of majors, and…

  16. Tuition Elasticity of the Demand for Higher Education among Current Students: A Pricing Model.

    ERIC Educational Resources Information Center

    Bryan, Glenn A.; Whipple, Thomas W.

    1995-01-01

    A pricing model is offered, based on retention of current students, that colleges can use to determine appropriate tuition. A computer-based model that quantifies the relationship between tuition elasticity and projected net return to the college was developed and applied to determine an appropriate tuition rate for a small, private liberal arts…

  17. Regional Differences in the Price-Elasticity of Demand for Energy

    SciTech Connect

    Bernstein, M. A.; Griffin, J.

    2006-02-01

    At the request of the National Renewable Energy Laboratory (NREL), the RAND Corporation examined the relationship between energy demand and energy prices with the focus on whether the relationships between demand and price differ if these are examined at different levels of data resolution. In this case, RAND compares national, regional, state, and electric utility levels of data resolution. This study is intended as a first step in helping NREL understand the impact that spatial disaggregation of data can have on estimating the impacts of their programs. This report should be useful to analysts in NREL and other national laboratories, as well as to policy nationals at the national level. It may help them understand the complex relationships between demand and price and how these might vary across different locations in the United States.

  18. Estimating the Market Demand and Elasticity for Enrollment at an Institution

    ERIC Educational Resources Information Center

    Wohlgemuth, Darin

    2013-01-01

    This article presents an applied research framework that can be helpful in tuition and net price policy discussions. It is the classic microeconomic concept of market demand applied to enrollment management in higher education. The policy relevance includes measuring a response to price. For example, the results of this model will allow the…

  19. The Effects of Price Discrimination on the Elasticity of Demand for Higher Education.

    ERIC Educational Resources Information Center

    Weinberg, Ira

    The purpose of this study was to determine what effect price discrimination (differential pricing) would have on institutional gross-fee income. Enrollment and tuition data were gathered from all schools in one particular market area for the years 1969-72. In this situation it was determined that overall demand for higher education was highly…

  20. The Effects of Price Discrimination on the Elasticity of Demand for Higher Education.

    ERIC Educational Resources Information Center

    Weinberg, Ira

    The purpose of this study was to determine what effect price discrimination (differential pricing) would have on institutional gross-fee income. Enrollment and tuition data were gathered from all schools in one particular market area for the years 1969-72. In this situation it was determined that overall demand for higher education was highly…

  1. Estimating the Market Demand and Elasticity for Enrollment at an Institution

    ERIC Educational Resources Information Center

    Wohlgemuth, Darin

    2013-01-01

    This article presents an applied research framework that can be helpful in tuition and net price policy discussions. It is the classic microeconomic concept of market demand applied to enrollment management in higher education. The policy relevance includes measuring a response to price. For example, the results of this model will allow the…

  2. Dynamic on-demand defragmentation in flexible bandwidth elastic optical networks.

    PubMed

    Yin, Yawei; Wen, Ke; Geisler, David J; Liu, Ruiting; Yoo, S J B

    2012-01-16

    While flexible bandwidth elastic optical networking is a promising direction for future networks, the spectral fragmentation problem in such a network inevitably raises the blocking probability and significantly degrades network performance. This paper addresses the spectral defragmentation problem using an auxiliary graph based approach, which transforms the problem into a matter of finding the maximum independent set (MIS) in the constructed auxiliary graph. The enabling technologies and defragmentation-capable node architectures, together with heuristic defragmentation algorithms are proposed and evaluated. Simulation results show that the proposed min-cost defragmentation algorithms can significantly reduce the blocking probability of incoming requests in a spectrally fragmented flexible bandwidth optical network, while substantially minimizing the number of disrupted connections.

  3. Assess the feasibility of the high-speed railway construction in China by measuring the traffic demand elastic

    NASA Astrophysics Data System (ADS)

    Yu, Nan; Cao, Yu

    2017-05-01

    The traffic demand elastic is proposed as a new indicator in this study to measure the feasibility of the high-speed railway construction in a more intuitive way. The Matrix Completion (MC) and Semi-Supervised Support Vector Machine (S3VM) are used to realize the measurement and prediction of this index on the basis of the satisfaction investigation on the 326 inter-city railways in china. It is demonstrated that instead of calculating the economic benefits brought by the construction of high-speed railway, this indicator can find the most urgent railways to be improved by directly evaluate the existing railway facilities from the perspective of transportation service improvement requirements.

  4. Short-run and long-run elasticities of electricity demand in the public sector: A case study of the United States Navy bases

    NASA Astrophysics Data System (ADS)

    Choi, Jino

    Numerous studies have examined the elasticities of electricity demand---residential as well as commercial and industrial---in the private sector. However, no one appears to have examined the behavior of the public sector demand. This study aims to fill that gap and to provide insights into the electricity demand in the public sector, using the U.S. Navy bases as a case study. This study examines electricity demand data of 38 Navy activities within the United States for a 16-year time period from 1985 through 2000. The Navy maintains a highly diverse shore infrastructure to conduct its mission and to support the fleet. The types of shore facilities include shipyards, air stations, aviation depots, hospital, and many others. These Navy activities are analogous to commercial or industrial organizations in the private sector. In this study, I used a number of analytical approaches to estimate short-run and long-run elasticities of electricity demand. Estimation using pooled data was rejected because it failed the test for homogeneity. Estimation using the time series data of each Navy activity had several wrong signs for coefficients. The Stein-rule estimator did not differ significantly from the separate cross-section estimates because of the strong rejection of the homogeneity assumption. The iterative Bayesian shrinkage estimator provided the most reasonable results. The empirical findings from this study are as follows. First, the Navy's electricity demand is price elastic. Second, the price elasticities appear to be lower than those of the private sector. The short-run price elasticities for the Navy activities ranged from -0.083 to -0.157. The long-run price elasticities ranged from -0.151 to -0.769.

  5. The impact of introducing patient co-payments in Germany on the use of IVF and ICSI: a price-elasticity of demand assessment.

    PubMed

    Connolly, M P; Griesinger, G; Ledger, W; Postma, M J

    2009-11-01

    Authorities concerned by rising healthcare costs have a tendency to target reproductive treatments because of the perception that infertility is a low priority. In 2004 German health authorities introduced a 50% co-payment for patients, in an effort to save cost. We explored the impact of this pricing policy on the utilization of reproductive treatments in Germany. Using aggregated annual in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycle data in Germany, we evaluated the relationship between changes in the number of cycles in relation to changes in costs faced by consumers following the introduction of a patient co-payment from 'no fees' to 1500-2000 euros by estimating the short-run price-elasticity of demand. The impact of introducing patient co-payments for IVF/ICSI on the likelihood of switching to other low-cost fertility treatments was evaluated using the cross-price elasticity methodology. RESULTS The reduction in demand for IVF and ICSI cycles in the year following the introduction of patient co-payments resulted in elasticities of -0.41 and -0.34, respectively. The price-elasticity for the combined reduction of IVF/ICSI in relation to the co-payment was estimated to be -0.36. The cross-price elasticity for clomifene was close to zero (-0.01) suggesting that demand for these interventions are independent of each other and no substitution occurred. We report price elasticities for IVF and ICSI of -0.41 and -0.34 after introducing a 500-2000 euros co-payment. These findings likely represent short-run elasticities that are likely to vary over time as factors that influence the supply and demand for fertility treatments change.

  6. Demand assessment and price-elasticity estimation of quality-improved primary health care in Palestine: a contribution from the contingent valuation method.

    PubMed

    Mataria, Awad; Luchini, Stéphane; Daoud, Yousef; Moatti, Jean-Paul

    2007-10-01

    This paper proposes a new methodology to assess demand and price-elasticity for health care, based on patients' stated willingness to pay (WTP) values for certain aspects of health care quality improvements. A conceptual analysis of how respondents consider contingent valuation (CV) questions allowed us to specify a probability density function of stated WTP values, and consequently, to model a demand function for quality-improved health care, using a parametric survival approach. The model was empirically estimated using a CV study intended to assess patients' values for improving the quality of primary health care (PHC) services in Palestine. A random sample of 499 individuals was interviewed following medical consultation in four PHC centers. Quality was assessed using a multi-attribute approach; and respondents valued seven specific quality improvements using a decomposed valuation scenario and a payment card elicitation technique. Our results suggest an inelastic demand at low user fees levels, and when the price-increase is accompanied with substantial quality-improvements. Nevertheless, demand becomes more and more elastic if user fees continue to rise. On the other hand, patients' reactions to price-increase turn out to depend on their level of income. Our results can be used to design successful health care financing strategies that include a consideration of patients' preferences and financial capacities.

  7. Estimation of own and cross price elasticities of alcohol demand in the UK--A pseudo-panel approach using the Living Costs and Food Survey 2001-2009.

    PubMed

    Meng, Yang; Brennan, Alan; Purshouse, Robin; Hill-McManus, Daniel; Angus, Colin; Holmes, John; Meier, Petra Sylvia

    2014-03-01

    The estimation of price elasticities of alcohol demand is valuable for the appraisal of price-based policy interventions such as minimum unit pricing and taxation. This study applies a pseudo-panel approach to the cross-sectional Living Cost and Food Survey 2001/2-2009 to estimate the own- and cross-price elasticities of off- and on-trade beer, cider, wine, spirits and ready-to-drinks in the UK. A pseudo-panel with 72 subgroups defined by birth year, gender and socioeconomic status is constructed. Estimated own-price elasticities from the base case fixed effect models are all negative and mostly statically significant (p<0.05). Off-trade cider and beer are most elastic (-1.27 and -0.98) and off-trade spirits and on-trade ready-to-drinks are least elastic (-0.08 and -0.19). Estimated cross-price elasticities are smaller in magnitude with a mix of positive and negative signs. The results appear plausible and robust and could be used for appraising the estimated impact of price-based interventions in the UK. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Estimation of own and cross price elasticities of alcohol demand in the UK—A pseudo-panel approach using the Living Costs and Food Survey 2001–2009☆

    PubMed Central

    Meng, Yang; Brennan, Alan; Purshouse, Robin; Hill-McManus, Daniel; Angus, Colin; Holmes, John; Meier, Petra Sylvia

    2014-01-01

    The estimation of price elasticities of alcohol demand is valuable for the appraisal of price-based policy interventions such as minimum unit pricing and taxation. This study applies a pseudo-panel approach to the cross-sectional Living Cost and Food Survey 2001/2–2009 to estimate the own- and cross-price elasticities of off- and on-trade beer, cider, wine, spirits and ready-to-drinks in the UK. A pseudo-panel with 72 subgroups defined by birth year, gender and socioeconomic status is constructed. Estimated own-price elasticities from the base case fixed effect models are all negative and mostly statically significant (p < 0.05). Off-trade cider and beer are most elastic (−1.27 and −0.98) and off-trade spirits and on-trade ready-to-drinks are least elastic (−0.08 and −0.19). Estimated cross-price elasticities are smaller in magnitude with a mix of positive and negative signs. The results appear plausible and robust and could be used for appraising the estimated impact of price-based interventions in the UK. PMID:24508846

  9. The Calculus of Elasticity

    ERIC Educational Resources Information Center

    Gordon, Warren B.

    2006-01-01

    This paper examines the elasticity of demand, and shows that geometrically, it may be interpreted as the ratio of two simple distances along the tangent line: the distance from the point on the curve to the x-intercept to the distance from the point on the curve to the y-intercept. It also shows that total revenue is maximized at the transition…

  10. Gasoline demand in developing Asian countries

    SciTech Connect

    McRae, R.

    1994-12-31

    This paper presents econometric estimates of motor gasoline demand in eleven developing countries of Asia. The price and GDP per capita elasticities are estimated for each country separately, and for several pooled combinations of the countries. The estimated elasticities for the Asian countries are compared with those of the OECD countries. Generally, one finds that the OECD countries have GDP elasticities that are smaller, and price elasticities that are larger (in absolute value). The price elasticities for the low-income Asian countries are more inelastic than for the middle-income Asian countries, and the GDP elasticities are generally more elastic. 13 refs., 6 tabs.

  11. Textbook Factor Demand Curves.

    ERIC Educational Resources Information Center

    Davis, Joe C.

    1994-01-01

    Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)

  12. Textbook Factor Demand Curves.

    ERIC Educational Resources Information Center

    Davis, Joe C.

    1994-01-01

    Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)

  13. Using Empirical Point Elasticities To Teach Tax Incidence.

    ERIC Educational Resources Information Center

    Swinton, John R.; Thomas, Christopher R.

    2001-01-01

    Advocates use of point elasticities rather than arc elasticities or slopes of demand and supply curves to teach students about the economic impacts of excise taxes. Uses several available estimates of point elasticities of demand and supply of sugar to calculate the economic impacts of a penny-per-pound tax on sugar. (RLH)

  14. Using Empirical Point Elasticities To Teach Tax Incidence.

    ERIC Educational Resources Information Center

    Swinton, John R.; Thomas, Christopher R.

    2001-01-01

    Advocates use of point elasticities rather than arc elasticities or slopes of demand and supply curves to teach students about the economic impacts of excise taxes. Uses several available estimates of point elasticities of demand and supply of sugar to calculate the economic impacts of a penny-per-pound tax on sugar. (RLH)

  15. A Reevaluation of Price Elasticities for Irrigation Water

    NASA Astrophysics Data System (ADS)

    Howitt, Richard E.; Watson, William D.; Adams, Richard M.

    1980-08-01

    The effectiveness of pricing systems in the allocation of irrigation water is linked with the price elasticity of demand of farmers for water. Using microeconomic theory, it is shown that omission of the elasticity of demand for the crop produced leads to an inelastic bias in the demand for irrigated water. Linear programing approaches omit the product elasticity of demand and are consequently biased, whereas quadratic programing approaches to estimating derived demands for irrigation water include product demand functions. The difference between the resulting estimates are empirically demonstrated for regional derived demand functions estimated from a model of California's agricultural industry.

  16. Rotational elasticity

    NASA Astrophysics Data System (ADS)

    Vassiliev, Dmitri

    2017-04-01

    We consider an infinite three-dimensional elastic continuum whose material points experience no displacements, only rotations. This framework is a special case of the Cosserat theory of elasticity. Rotations of material points are described mathematically by attaching to each geometric point an orthonormal basis that gives a field of orthonormal bases called the coframe. As the dynamical variables (unknowns) of our theory, we choose the coframe and a density. We write down the general dynamic variational functional for our rotational theory of elasticity, assuming our material to be physically linear but the kinematic model geometrically nonlinear. Allowing geometric nonlinearity is natural when dealing with rotations because rotations in dimension three are inherently nonlinear (rotations about different axes do not commute) and because there is no reason to exclude from our study large rotations such as full turns. The main result of the talk is an explicit construction of a class of time-dependent solutions that we call plane wave solutions; these are travelling waves of rotations. The existence of such explicit closed-form solutions is a non-trivial fact given that our system of Euler-Lagrange equations is highly nonlinear. We also consider a special case of our rotational theory of elasticity which in the stationary setting (harmonic time dependence and arbitrary dependence on spatial coordinates) turns out to be equivalent to a pair of massless Dirac equations. The talk is based on the paper [1]. [1] C.G.Boehmer, R.J.Downes and D.Vassiliev, Rotational elasticity, Quarterly Journal of Mechanics and Applied Mathematics, 2011, vol. 64, p. 415-439. The paper is a heavily revised version of preprint https://arxiv.org/abs/1008.3833

  17. Robust Unit Commitment Considering Uncertain Demand Response

    DOE PAGES

    Liu, Guodong; Tomsovic, Kevin

    2014-09-28

    Although price responsive demand response has been widely accepted as playing an important role in the reliable and economic operation of power system, the real response from demand side can be highly uncertain due to limited understanding of consumers' response to pricing signals. To model the behavior of consumers, the price elasticity of demand has been explored and utilized in both research and real practice. However, the price elasticity of demand is not precisely known and may vary greatly with operating conditions and types of customers. To accommodate the uncertainty of demand response, alternative unit commitment methods robust to themore » uncertainty of the demand response require investigation. In this paper, a robust unit commitment model to minimize the generalized social cost is proposed for the optimal unit commitment decision taking into account uncertainty of the price elasticity of demand. By optimizing the worst case under proper robust level, the unit commitment solution of the proposed model is robust against all possible realizations of the modeled uncertain demand response. Numerical simulations on the IEEE Reliability Test System show the e ectiveness of the method. Finally, compared to unit commitment with deterministic price elasticity of demand, the proposed robust model can reduce the average Locational Marginal Prices (LMPs) as well as the price volatility.« less

  18. Robust Unit Commitment Considering Uncertain Demand Response

    SciTech Connect

    Liu, Guodong; Tomsovic, Kevin

    2014-09-28

    Although price responsive demand response has been widely accepted as playing an important role in the reliable and economic operation of power system, the real response from demand side can be highly uncertain due to limited understanding of consumers' response to pricing signals. To model the behavior of consumers, the price elasticity of demand has been explored and utilized in both research and real practice. However, the price elasticity of demand is not precisely known and may vary greatly with operating conditions and types of customers. To accommodate the uncertainty of demand response, alternative unit commitment methods robust to the uncertainty of the demand response require investigation. In this paper, a robust unit commitment model to minimize the generalized social cost is proposed for the optimal unit commitment decision taking into account uncertainty of the price elasticity of demand. By optimizing the worst case under proper robust level, the unit commitment solution of the proposed model is robust against all possible realizations of the modeled uncertain demand response. Numerical simulations on the IEEE Reliability Test System show the e ectiveness of the method. Finally, compared to unit commitment with deterministic price elasticity of demand, the proposed robust model can reduce the average Locational Marginal Prices (LMPs) as well as the price volatility.

  19. Impact of improved building thermal efficiency on residential energy demand

    SciTech Connect

    Adams, R.C.; Rockwood, A.D.

    1983-04-01

    The impact of improved building shell thermal efficiency on residential energy demand is explored in a theoretical framework. The important economic literature on estimating the price elasticity of residential energy demand is reviewed. The specification of the residential energy demand model is presented. The data used are described. The empirical estimation of the residential energy demand model is described. (MHR)

  20. The Demand for Higher Education: Pennsylvania's Nonresident Tuition Experience.

    ERIC Educational Resources Information Center

    Noorbakhsh, Abbas; Culp, David

    2002-01-01

    Explores the estimation of tuition elasticity of resident and nonresident demand for higher education in the Pennsylvania State System of Higher Education. Finds that nonresident demand is price elastic, thus explaining the 40 percent decline in nonresident enrollment between 1991 and 1996 after average nonresident tuition increased nearly 20…

  1. The Demand for Higher Education Facing an Individual Institution

    ERIC Educational Resources Information Center

    Ghali, Moheb; And Others

    1977-01-01

    A model is used to analyze the choices made by a sample of high school graduates in Hawaii and estimates of the price elasticity and the cross-price elasticities of demand for enrollment at the University of Hawaii are obtained. Findings show that the demand is quite inelastic and that changes in tuition will not affect enrollment appreciably.…

  2. The Demand for Higher Education Facing an Individual Institution

    ERIC Educational Resources Information Center

    Ghali, Moheb; And Others

    1977-01-01

    A model is used to analyze the choices made by a sample of high school graduates in Hawaii and estimates of the price elasticity and the cross-price elasticities of demand for enrollment at the University of Hawaii are obtained. Findings show that the demand is quite inelastic and that changes in tuition will not affect enrollment appreciably.…

  3. The Demand for Higher Education: Pennsylvania's Nonresident Tuition Experience.

    ERIC Educational Resources Information Center

    Noorbakhsh, Abbas; Culp, David

    2002-01-01

    Explores the estimation of tuition elasticity of resident and nonresident demand for higher education in the Pennsylvania State System of Higher Education. Finds that nonresident demand is price elastic, thus explaining the 40 percent decline in nonresident enrollment between 1991 and 1996 after average nonresident tuition increased nearly 20…

  4. Elastic Fluctuations and Rubber Elasticity

    NASA Astrophysics Data System (ADS)

    Xing, Xiangjun; Goldbart, Paul; Rradzihovsky, Leo

    2006-03-01

    A coarse-grained phenomenological model is constructed to describe both phonon fluctuations and elastic heterogeneities in rubbery materials. It is a nonlocal, spatially heterogeneous generalization of the classical model of rubber elasticity, and with a tunable repulsion interaction. This model can also be derived from the Vulcanization theory. The residual stress and the non-affine deformation field, as well as their correlations, are calculated perturbatively, to the leading order of quenched randomness. It is explicitly shown that the interplay between the repulsive interaction and quenched randomness induces non- affine deformation. The spatial correlations of the non- affine deformation field and residual stress exhibit power-law scaling, with no characteristic length scale. We also calculate the contributions to the elastic free energy from both thermal and quenched fluctuations for arbitrary deformation. We find that they naturally explain the universal features in the Mooney-Rivlin plot of the stress-strain curve for rubbery materials. The (disorder averaged) thermal fluctuation of monomers is shown to depend on deformation, and becomes anisotropic upon shear deformation, as long as the repulsive interaction is finite.

  5. Demanding Satisfaction

    ERIC Educational Resources Information Center

    Oguntoyinbo, Lekan

    2010-01-01

    It was the kind of crisis most universities dread. In November 2006, a group of minority student leaders at Indiana University-Purdue University Indianapolis (IUPUI) threatened to sue the university if administrators did not heed demands that included providing more funding for multicultural student groups. This article discusses how this threat…

  6. Two Propositions on the Application of Point Elasticities to Finite Price Changes.

    ERIC Educational Resources Information Center

    Daskin, Alan J.

    1992-01-01

    Considers counterintuitive propositions about using point elasticities to estimate quantity changes in response to price changes. Suggests that elasticity increases with price along a linear demand curve, but falling quantity demand offsets it. Argues that point elasticity with finite percentage change in price only approximates percentage change…

  7. Two Propositions on the Application of Point Elasticities to Finite Price Changes.

    ERIC Educational Resources Information Center

    Daskin, Alan J.

    1992-01-01

    Considers counterintuitive propositions about using point elasticities to estimate quantity changes in response to price changes. Suggests that elasticity increases with price along a linear demand curve, but falling quantity demand offsets it. Argues that point elasticity with finite percentage change in price only approximates percentage change…

  8. On the demand for prescription drugs: heterogeneity in price responses.

    PubMed

    Skipper, Niels

    2013-07-01

    This paper estimates the price elasticity of demand for prescription drugs using an exogenous shift in consumer co-payment caused by a reform in the Danish subsidy scheme for the general public. Using purchasing records for the entire Danish population, I show that the average price response for the most commonly used drug yields demand elasticities in the range of -0.36 to -0.5. The reform is shown to affect women, the elderly, and immigrants the most. Furthermore, this paper shows significant heterogeneity in the price response over different types of antibiotics, suggesting that the price elasticity of demand varies considerably even across relatively similar drugs.

  9. Can price get the monkey off our back? A meta-analysis of illicit drug demand.

    PubMed

    Gallet, Craig A

    2014-01-01

    Because of the increased availability of price data over the past 15 years, several studies have estimated the demand for illicit drugs, providing 462 estimates of the price elasticity. Results from estimating several meta-regressions reveal that these price elasticity estimates are influenced by a number of study characteristics. For instance, the price elasticity differs across drugs, with its absolute value being smallest for marijuana, compared with cocaine and heroin. Furthermore, price elasticity estimates are sensitive to whether demand is modeled in the short-run or the long-run, measures of quantity and price, whether or not alcohol and other illicit drugs are included in the specification of demand, and the location of demand. However, a number of other factors, including the functional form of demand, several specification issues, the type of data and method used to estimate demand, and the quality of the publication outlet, have less influence on the price elasticity.

  10. Estimating demand for alternatives to cigarettes with online purchase tasks.

    PubMed

    O'Connor, Richard J; June, Kristie M; Bansal-Travers, Maansi; Rousu, Matthew C; Thrasher, James F; Hyland, Andrew; Cummings, K Michael

    2014-01-01

    To explore how advertising affects demand for cigarettes and potential substitutes, including snus, dissolvable tobacco, and medicinal nicotine. A Web-based experiment randomized 1062 smokers to see advertisements for alternative nicotine products or soft drinks, then complete a series of purchase tasks, which were used to estimate demand elasticity, peak consumption, and cross-price elasticity (CPE) for tobacco products. Lower demand elasticity and greater peak consumption were seen for cigarettes compared to all alternative products (p < .05). CPE did not differ across the alternative products (p ≤ .03). Seeing relevant advertisements was not significantly related to demand. These findings suggest significantly lower demand for alternative nicotine sources among smokers than previously revealed.

  11. Estimating Demand for Alternatives to Cigarettes With Online Purchase Tasks

    PubMed Central

    O’Connor, Richard J.; June, Kristie M.; Bansal-Travers, Maansi; Rousu, Matthew C.; Thrasher, James F.; Hyland, Andrew; Cummings, K. Michael

    2013-01-01

    Objectives This study explored how advertising affects demand for cigarettes and potential substitutes, including snus, dissolvable tobacco, and medicinal nicotine. Methods A web-based experiment randomized 1062 smokers to see advertisements for alternative nicotine products or soft drinks, then complete a series of purchase tasks, which were used to estimate demand elasticity, peak consumption, and cross-price elasticity (CPE) for tobacco products. Results Lower demand elasticity and greater peak consumption were seen for cigarettes compared to all alternative products (p < .05). CPE did not differ across the alternative products (p ≤ .03). Seeing relevant advertisements was not significantly related to demand. Conclusions These findings suggest significantly lower demand for alternative nicotine sources among smokers than previously revealed. PMID:24034685

  12. [Cigarette taxes and demand in Colombia].

    PubMed

    Maldonado, Norman; Llorente, Blanca; Deaza, Javier

    2016-10-01

    Estimate price and income elasticities of aggregate demand for cigarettes in Colombia, by controlling for structural market changes since the late 1990s, to identify policy opportunities for taxes that could improve public health and increase tax revenues. Measurement of aggregate demand for cigarettes using gross income reported on value-added tax returns submitted to Colombia's National Tax and Customs Office (DIAN is the acronym in Spanish) by the tobacco product manufacturing industry, subtracting exports. A quarterly time series was obtained for the period 1994-2014. The econometric estimation using two-stage least squares controls for price endogeneity and uses a set of dummy variables to control for structural changes in the market and in its regulation. Demand is, from a statistical standpoint, sensitive to price and to income. Price elasticity of demand is -0.78 and income elasticity is 0.61. Inelastic demand implies that it is possible, through cigarette excise taxes, to meet public health targets and increase revenues simultaneously. The results also suggest that the considerable increase in household income in Colombia in the first decade of the 21st century increased purchasing power, which, lacking an accompanying tax increase, promoted cigarette consumption, with negative effects on public health, and wasted an opportunity to increase tax revenues.

  13. Advertising media and cigarette demand.

    PubMed

    Goel, Rajeev K

    2011-01-01

    Using state-level panel data for the USA spanning three decades, this research estimates the demand for cigarettes. The main contribution lies in studying the effects of cigarette advertising disaggregated across five qualitatively different groups. Results show cigarette demand to be near unit elastic, the income effects to be generally insignificant and border price effects and habit effects to be significant. Regarding advertising effects, aggregate cigarette advertising has a negative effect on smoking. Important differences across advertising media emerge when cigarette advertising is disaggregated. The effects of public entertainment and Internet cigarette advertising are stronger than those of other media. Anti-smoking messages accompanying print cigarette advertising seem relatively more effective. Implications for smoking control policy are discussed.

  14. Alcohol demand and risk preference.

    PubMed

    Dave, Dhaval; Saffer, Henry

    2008-12-01

    Both economists and psychologists have studied the concept of risk preference. Economists categorize individuals as more or less risk-tolerant based on the marginal utility of income. Psychologists categorize individuals' propensity towards risk based on harm avoidance, novelty seeking and reward dependence traits. The two concepts of risk are related, although the instruments used for empirical measurement are quite different. Psychologists have found risk preference to be an important determinant of alcohol consumption; however economists have not included risk preference in studies of alcohol demand. This is the first study to examine the effect of risk preference on alcohol consumption in the context of a demand function. The specifications employ multiple waves from the Panel Study of Income Dynamics (PSID) and the Health and Retirement Study (HRS), which permit the estimation of age-specific models based on nationally representative samples. Both of these data sets include a unique and consistent survey instrument designed to directly measure risk preference in accordance with the economist's definition. This study estimates the direct impact of risk preference on alcohol demand and also explores how risk preference affects the price elasticity of demand. The empirical results indicate that risk preference has a significant negative effect on alcohol consumption, with the prevalence and consumption among risk-tolerant individuals being 6-8% higher. Furthermore, the tax elasticity is similar across both risk-averse and risk-tolerant individuals. This suggests that tax policies are as equally effective in deterring alcohol consumption among those who have a higher versus a lower propensity for alcohol use.

  15. Modeling water demand when households have multiple sources of water

    NASA Astrophysics Data System (ADS)

    Coulibaly, Lassina; Jakus, Paul M.; Keith, John E.

    2014-07-01

    A significant portion of the world's population lives in areas where public water delivery systems are unreliable and/or deliver poor quality water. In response, people have developed important alternatives to publicly supplied water. To date, most water demand research has been based on single-equation models for a single source of water, with very few studies that have examined water demand from two sources of water (where all nonpublic system water sources have been aggregated into a single demand). This modeling approach leads to two outcomes. First, the demand models do not capture the full range of alternatives, so the true economic relationship among the alternatives is obscured. Second, and more seriously, economic theory predicts that demand for a good becomes more price-elastic as the number of close substitutes increases. If researchers artificially limit the number of alternatives studied to something less than the true number, the price elasticity estimate may be biased downward. This paper examines water demand in a region with near universal access to piped water, but where system reliability and quality is such that many alternative sources of water exist. In extending the demand analysis to four sources of water, we are able to (i) demonstrate why households choose the water sources they do, (ii) provide a richer description of the demand relationships among sources, and (iii) calculate own-price elasticity estimates that are more elastic than those generally found in the literature.

  16. Estimating Demand Elasticities for Mobile Telecommunications in Austria

    DTIC Science & Technology

    2004-12-01

    Telecommunications Pol- icy, 27, 457-476. RTR, 2004, Informationen fiber den Telekom- Markt in Osterreich, Vienna, http://www.rtr. at/web .nsf/deutsch...Foreign Direct Investment, Production, and Welfare, No. 11 (June 2003). "* Dewenter, Ralf, The Economics of Media Markets, No. 10 (June 2003). "* Josten...Briduninger, Michael, A Note on Health Insurance and Growth, No. 6 (June 2003). * Dewenter, Ralf, Media Markets with Habit Formation, No. 5 (June

  17. Excise Taxes and the Price Elasticity of Demand.

    ERIC Educational Resources Information Center

    Gamble, Ralph C., Jr.

    1989-01-01

    Points out that, although the analysis of the imposition of an excise tax is widely used in economics courses, the consequences of a change in the tax rate are different and ignored. This article presents an effective way to teach about such a change. (GG)

  18. Excise Taxes and the Price Elasticity of Demand.

    ERIC Educational Resources Information Center

    Gamble, Ralph C., Jr.

    1989-01-01

    Points out that, although the analysis of the imposition of an excise tax is widely used in economics courses, the consequences of a change in the tax rate are different and ignored. This article presents an effective way to teach about such a change. (GG)

  19. Non-urban mobile radio market demand forecast

    NASA Technical Reports Server (NTRS)

    Castruccio, P. A.; Cooper, J.

    1982-01-01

    A national nonmetropolitan land mobile traffic model for 1990-2000 addresses user classes, density classes, traffic mix statistics, distance distribution, geographic distribution, price elasticity, and service quality elasticity. Traffic demands for business, special industrial, and police were determined on the basis of surveys in 73 randomly selected nonurban counties. The selected services represent 69% of total demand. The results were extrapolated to all services in the non-SMSA areas of the contiguous United States. Radiotelephone services were considered separately. Total non-SMSA mobile radio demand (one way) estimates are given. General functional requirements include: hand portability, privacy, reduction of blind spots, two way data transmission, position location, slow scan imagery.

  20. Non-urban mobile radio market demand forecast

    NASA Astrophysics Data System (ADS)

    Castruccio, P. A.; Cooper, J.

    1982-06-01

    A national nonmetropolitan land mobile traffic model for 1990-2000 addresses user classes, density classes, traffic mix statistics, distance distribution, geographic distribution, price elasticity, and service quality elasticity. Traffic demands for business, special industrial, and police were determined on the basis of surveys in 73 randomly selected nonurban counties. The selected services represent 69% of total demand. The results were extrapolated to all services in the non-SMSA areas of the contiguous United States. Radiotelephone services were considered separately. Total non-SMSA mobile radio demand (one way) estimates are given. General functional requirements include: hand portability, privacy, reduction of blind spots, two way data transmission, position location, slow scan imagery.

  1. The demand for nicotine replacement therapies.

    PubMed

    Tauras, John A; Chaloupka, Frank J

    2003-04-01

    This paper reports on the first econometric study to examine the determinants of nicotine replacement therapy (NRT) demand. Pooled cross-sectional time-series scanner-based data for 50 major metropolitan markets in the United States covering the period between the second quarter 1996 and the third quarter 1999 are used in the analysis. Fixed-effects modeling is employed to assess the impact of NRT prices, cigarette prices, and other determinants on NRT demand. The estimates indicate that decreases in the price of NRT and increases in the price of cigarettes would lead to substantial increases in per-capita sales of NRT products. The average own-price elasticity of demand, which measures the responsiveness of consumer demand for NRT products to changes in the price of NRT, for Nicoderm CQ and Nicorette, is -2.33 and -2.46, respectively. The average cross-price elasticity of demand, which measures the responsiveness of consumer demand for NRT products to changes in the price of cigarettes, for Nicoderm CQ and Nicorette, is 0.772 and 0.764, respectively.

  2. Rural electric demand research

    SciTech Connect

    Stetson, L.E.; Stark, G.L.

    1985-09-01

    In cooperative research with rural power suppliers in Nebraska, 35 recording demand meters were installed. The demand study was started in December of 1980 and concluded in March of 1983. Data collection in Nebraska was concentrated in a five-county area in eastcentral Nebraska. Customers were sampled based on a stratified randomized design. Electrical demands were recorded for 5-min intervals. Coincidental peak demands for 60-min intervals were determined for selected peak power use days in 1981 and 1982. In addition, 15-min coincidental demands showing maximum average and minimum demands for each month for the two-year study are presented. Demands predicted by the Rural Electrification Administration demand tables were generally lower than the measured demands while demands predicted by linear regression analysis were higher than the measured demands. Measured coincidental peak demands per customer for the total of all stratified groups ranged from 5.7 to 8.6 kW.

  3. Elastically Decoupling Dark Matter.

    PubMed

    Kuflik, Eric; Perelstein, Maxim; Lorier, Nicolas Rey-Le; Tsai, Yu-Dai

    2016-06-03

    We present a novel dark matter candidate, an elastically decoupling relic, which is a cold thermal relic whose present abundance is determined by the cross section of its elastic scattering on standard model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross section with electrons, photons and/or neutrinos in the 10^{-3}-1  fb range.

  4. Elastic internal flywheel gimbal

    SciTech Connect

    Rabenhorst, D.W.

    1981-01-13

    An elastic joint mounting and rotatably coupling a rotary inertial energy storage device or flywheel, to a shaft, the present gimbal structure reduces vibration and shock while allowing precession of the flywheel without the need for external gimbal mounts. The present elastic joint usually takes the form of an annular elastic member either integrally formed into the flywheel as a centermost segment thereof or attached to the flywheel or flywheel hub member at the center thereof, the rotary shaft then being mounted centrally to the elastic member.

  5. Elastic properties of minerals

    SciTech Connect

    Aleksandrov, K.S.; Prodaivoda, G.T.

    1993-09-01

    Investigations of the elastic properties of the main rock-forming minerals were begun by T.V. Ryzhova and K.S. Aleksandrov over 30 years ago on the initiative of B.P. Belikov. At the time, information on the elasticity of single crystals in general, and especially of minerals, was very scanty. In the surveys of that time there was information on the elasticity of 20 or 30 minerals. These, as a rule, did not include the main rock-forming minerals; silicates were represented only by garnets, quartz, topaz, tourmaline, zircon, beryl, and staurolite, which are often found in nature in the form of large and fairly high-quality crystals. Then and even much later it was still necessary to prove a supposition which now seems obvious: The elastic properties of rocks, and hence the velocities of elastic (seismic) waves in the earth`s crust, are primarily determined by the elastic characteristics of the minerals composing these rocks. Proof of this assertion, with rare exceptions of mono-mineralic rocks (marble, quartzite, etc.) cannot be obtained without information on the elasticities of a sufficiently large number of minerals, primarily framework, layer, and chain silicates which constitute the basis of most rocks. This also served as the starting point and main problem of the undertakings of Aleksandrov, Ryzhova, and Belikov - systematic investigations of the elastic properties of minerals and then of various rocks. 108 refs., 7 tabs.

  6. Asymmetric demand for energy: A cointegration approach

    NASA Astrophysics Data System (ADS)

    Maclean, Thomas Frank

    1997-12-01

    This paper uses time series data in a study of the demand for energy. One goal is to compare the results from the traditional autoregressive distributed lag (ADL) model to the error correction model (ECM) using cointegration. The second goal is to determine if the demand elasticity is asymmetric with respect to increasing and decreasing prices. This paper discusses three topics that are important to the use of time series data. The first topic is the presence and consequences unit roots which are common in time series data. The second topic is the identification of cointegrated variables and the third topic is a development of the ECM. This results in a model that can be used in either a single equation or multivariate system context and it will estimate both long run and short run elasticities. Asymmetry theory and its implications are studied along with an investigation into competing methods of creating the asymmetric variables. Simulations provided evidence that the use of dummy variables results in biased estimates and that the cumulative difference method of Wolffram/Houck gives valid estimates. The results of the empirical part of the paper show that the short run estimates of the ADL model are like those of the error correction model, but the cointegration method's long run estimates are better since they are known to be consistent and asymptotically unbiased. Tests for asymmetry do not support the theory of asymmetric long run price elasticities; however there is evidence to support the presence of asymmetric demand in the short run.

  7. A Simultaneous Equation Demand Model for Block Rates

    NASA Astrophysics Data System (ADS)

    Agthe, Donald E.; Billings, R. Bruce; Dobra, John L.; Raffiee, Kambiz

    1986-01-01

    This paper examines the problem of simultaneous-equations bias in estimation of the water demand function under an increasing block rate structure. The Hausman specification test is used to detect the presence of simultaneous-equations bias arising from correlation of the price measures with the regression error term in the results of a previously published study of water demand in Tucson, Arizona. An alternative simultaneous equation model is proposed for estimating the elasticity of demand in the presence of block rate pricing structures and availability of service charges. This model is used to reestimate the price and rate premium elasticities of demand in Tucson, Arizona for both the usual long-run static model and for a simple short-run demand model. The results from these simultaneous equation models are consistent with a priori expectations and are unbiased.

  8. On granular elasticity

    PubMed Central

    Sun, Qicheng; Jin, Feng; Wang, Guangqian; Song, Shixiong; Zhang, Guohua

    2015-01-01

    Mesoscopic structures form in dense granular materials due to the self-organisation of the constituent particles. These structures have internal structural degrees of freedom in addition to the translational degree of freedom. The resultant granular elasticity, which exhibits intrinsic variations and inevitable relaxation, is a key quantity that accounts for macroscopic solid- or fluid-like properties and the transitions between them. In this work, we propose a potential energy landscape (PEL) with local stable basins and low elastic energy barriers to analyse the nature of granular elasticity. A function for the elastic energy density is proposed for stable states and is further calibrated with ultrasonic measurements. Fluctuations in the elastic energy due to the evolution of internal structures are proposed to describe a so-called configuration temperature Tc as a counterpart of the classical kinetic granular temperature Tk that is attributed to the translational degrees of freedom. The two granular temperatures are chosen as the state variables, and a fundamental equation is established to develop non-equilibrium thermodynamics for granular materials. Due to the relatively low elastic energy barrier in the PEL, granular elasticity relaxes more under common mechanical loadings, and a simple model based on mean-field theory is developed to account for this behaviour. PMID:25951049

  9. Elastic membranes in confinement

    NASA Astrophysics Data System (ADS)

    Bostwick, Joshua; Miksis, Michael; Davis, Stephen

    2014-11-01

    An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. Many biological structures, such as cells, mitochondria and DNA, have finer internal structure in which a membrane (or elastic member) is geometrically ``confined'' by another object. We study the shape stability of elastic membranes in a ``confining'' box and introduce repulsive van der Waals forces to prevent the membrane from intersecting the wall. We aim to define the parameter space associated with mitochondria-like deformations. We compare the confined to `unconfined' solutions and show how the structure and stability of the membrane shapes changes with the system parameters.

  10. Elastic scattering phenomenology

    NASA Astrophysics Data System (ADS)

    Mackintosh, R. S.

    2017-04-01

    We argue that, in many situations, fits to elastic scattering data that were historically, and frequently still are, considered "good", are not justifiably so describable. Information about the dynamics of nucleon-nucleus and nucleus-nucleus scattering is lost when elastic scattering phenomenology is insufficiently ambitious. It is argued that in many situations, an alternative approach is appropriate for the phenomenology of nuclear elastic scattering of nucleons and other light nuclei. The approach affords an appropriate means of evaluating folding models, one that fully exploits available empirical data. It is particularly applicable for nucleons and other light ions.

  11. [Demand for cigarettes and tax increases in El Salvador].

    PubMed

    Ramos-Carbajales, Alejandro; González-Rozada, Martín; Vallarino, Hugo

    2016-10-01

    Analyze short- and long-term elasticities of demand for cigarettes in El Salvador as a tool for supporting recommendations on tax increases to reduce prevalence and consumption through price increases. Demand for cigarettes in El Salvador was analyzed through an econometric time-series model using a database from El Salvador's General Directorate of Internal Taxes (DGII) and the General Directorate of Statistics and Census (DIGESTYC). The analysis period was quarterly: 2000Q1-2012Q4. The usual tests were done to prevent a spurious econometric estimation. It was found that the variables volume sales, actual sale prices, and actual per capita income exhibited first-order cointegration; this result makes it possible to use an error correction model with short- and long-term elasticity estimates. Only long-term elasticities were found to be statistically significant to 5%. Results show long-term price elasticity (5 quarters) of -0.9287 and income price elasticity of 0.9978. Absolute price elasticity is somewhat high, although it is within the levels estimated in other studies in low per-capita income countries. A tax increase from a base amount of US$1.04 per pack of 20 cigarettes to US$1.66 within three years would reduce demand by 20% to 31% and would increase tax revenues by 9% to 22%.

  12. Price responsiveness of demand for cigarettes: does rationality matter?

    PubMed

    Laporte, Audrey

    2006-01-01

    Meta-analysis is applied to aggregate-level studies that model the demand for cigarettes using static, myopic, or rational addiction frameworks in an attempt to synthesize key findings in the literature and to identify determinants of the variation in reported price elasticity estimates across studies. The results suggest that the rational addiction framework produces statistically similar estimates to the static framework but that studies that use the myopic framework tend to report more elastic price effects. Studies that applied panel data techniques or controlled for cross-border smuggling reported more elastic price elasticity estimates, whereas the use of instrumental variable techniques and time trends or time dummy variables produced less elastic estimates. The finding that myopic models produce different estimates than either of the other two model frameworks underscores that careful attention must be given to time series properties of the data.

  13. Mechanism of Resilin Elasticity

    PubMed Central

    Qin, Guokui; Hu, Xiao; Cebe, Peggy; Kaplan, David L.

    2012-01-01

    Resilin is critical in the flight and jumping systems of insects as a polymeric rubber-like protein with outstanding elasticity. However, insight into the underlying molecular mechanisms responsible for resilin elasticity remains undefined. Here we report the structure and function of resilin from Drosophila CG15920. A reversible beta-turn transition was identified in the peptide encoded by exon III and for full length resilin during energy input and release, features that correlate to the rapid deformation of resilin during functions in vivo. Micellar structures and nano-porous patterns formed after beta-turn structures were present via changes in either the thermal or mechanical inputs. A model is proposed to explain the super elasticity and energy conversion mechanisms of resilin, providing important insight into structure-function relationships for this protein. Further, this model offers a view of elastomeric proteins in general where beta-turn related structures serve as fundamental units of the structure and elasticity. PMID:22893127

  14. Approximate formulas for elasticity of the Tornquist functions and some their advantages

    NASA Astrophysics Data System (ADS)

    Issin, Meyram

    2017-09-01

    In this article functions of demand for prime necessity, second necessity and luxury goods depending on the income are considered. These functions are called Tornquist functions. By means of the return model the demand for prime necessity goods and second necessity goods are approximately described. Then on the basis of a method of the smallest squares approximate formulas for elasticity of these Tornquist functions are received. To receive an approximate formula for elasticity of function of demand for luxury goods, the linear asymptotic formula is constructed for this function. Some benefits of approximate formulas for elasticity of Tornquist functions are specified.

  15. Health insurance and the demand for medical care: Instrumental variable estimates using health insurer claims data.

    PubMed

    Dunn, Abe

    2016-07-01

    This paper takes a different approach to estimating demand for medical care that uses the negotiated prices between insurers and providers as an instrument. The instrument is viewed as a textbook "cost shifting" instrument that impacts plan offerings, but is unobserved by consumers. The paper finds a price elasticity of demand of around -0.20, matching the elasticity found in the RAND Health Insurance Experiment. The paper also studies within-market variation in demand for prescription drugs and other medical care services and obtains comparable price elasticity estimates. Published by Elsevier B.V.

  16. Deflation of elastic surfaces

    NASA Astrophysics Data System (ADS)

    Quilliet, Catherine; Quemeneur, François; Marmottant, Philippe; Imhof, Arnout; Pépin-Donat, Brigitte; van Blaaderen, Alfons

    2010-03-01

    The deflation of elastic spherical surfaces has been numerically investigated, and show very different types of deformations according the range of elastic parameters, some of them being quantitatively explained through simple calculations. This allows to retrieve various shapes observed on hollow shells (from colloidal to centimeter scale), on lipid vesicles, or on some biological objects. The extension of this process to other geometries allows to modelize vegetal objects such as the ultrafast trap of carnivorous plants.

  17. Electricity demand curtailment planning

    SciTech Connect

    Allentuck, J; Carroll, O; Schnader, M

    1980-01-01

    The state of electricity demand curtailment planning for long term electricity supply disruptions is reviewed. Legal, institutional and technological problems associated with demand curtailment plans are examined, and the existence of well defined social objectives on the part of planners is questioned. A linear programming approach to electricity demand curtailment planning is presented.

  18. Demand Response Analysis Tool

    SciTech Connect

    2012-03-01

    Demand Response Analysis Tool is a software developed at the Lawrence Berkeley National Laboratory. It is initially funded by Southern California Edison. Our goal in developing this tool is to provide an online, useable, with standardized methods, an analysis tool to evaluate demand and demand response performance of commercial and industrial facilities. The tool provides load variability and weather sensitivity analysis capabilities as well as development of various types of baselines. It can be used by researchers, real estate management firms, utilities, or any individuals who are interested in analyzing their demand and demand response capabilities.

  19. Demand for general practitioner and internist services.

    PubMed Central

    Guzick, D S

    1978-01-01

    Demand equations for general-practitioner and internist visits were estimated from 1970 CHAS-NORC survey data on health-service utilization and expenditure. Because a large proportion of respondents reported zero visits, observations were grouped according to cross-classified independent variables and regression analyses were performed using group means as data. The results showed significant differences between demand equations for general-practitioner visits and those for internist visits. Of potential importance was an apparent substitution of internists for general practitioners as ability to pay (income or insurance coverage) increased. Own-price elasticities were low for both general practitioners and internists but were even lower for the latter (0.1 to 0.02) than the former (0.2 to 0.3). The demand for services of the two specialties also differed with respect to disability days, age, sex, residence, and race. PMID:738894

  20. Elastic Granular Flows

    NASA Astrophysics Data System (ADS)

    Campbell, C. S.

    2014-12-01

    The dry granular flowmap can be broken into two broad categories, the Elastic and the Inertial. Elastic flows are dominated by force chains and stresses are generated by the compression of the interparticle contacts within those chains, and thus are proportional to the stiffness of the contacts. The Elastic zone can be subdivided into two regimes, the Elastic-Quasistatic where forces are independent of the shear rate which at high shear rates transitions to Elastic-Inertial where the particle inertia is reflected in the forces and the stresses increase linearly with the shear rate. In the Inertial regime, the stresses vary with the square of the shear rate. It also is divided into two regimes, the Dense-Inertial where the flow is dominated by clusters of particles, and the Inertial-Collisional where the flow is dominated by binary collisions. Appropriately the elastic theory grew out of an old study of landslides. But like most such studies, all of the above depend on idealized computer simulations of uniform sized spherical particles. Real particles are never round, never of uniform size, and the process of flowing changes surface properties and may even shatter the particles. But all indications are that real systems still fit into the pattern drawn out in the last paragraph. A grave problem facing the field is how to incorporate these effects without losing a fundamental understanding of the internal rheological processes. This talk will begin with an overview of the Elastic flowmap and the behaviors associated with each flow regime. It will then discuss early work to include effects of particle shape and size mixtures and perhaps some effects of particle breakage.

  1. Elasticity of plagioclase feldspars

    NASA Astrophysics Data System (ADS)

    Brown, J. Michael; Angel, Ross J.; Ross, Nancy L.

    2016-02-01

    Elastic properties are reported for eight plagioclase feldspars that span compositions from albite (NaSi3AlO8) to anorthite (CaSi2Al2O8). Surface acoustic wave velocities measured using Impulsive Stimulated Light Scattering and compliance sums from high-pressure X-ray compression studies accurately determine all 21 components of the elasticity tensor for these triclinic minerals. The overall pattern of elasticity and the changes in individual elastic components with composition can be rationalized on the basis of the evolution of crystal structures and chemistry across this solid-solution join. All plagioclase feldspars have high elastic anisotropy; a* (the direction perpendicular to the b and c axes) is the softest direction by a factor of 3 in albite. From albite to anorthite the stiffness of this direction undergoes the greatest change, increasing twofold. Small discontinuities in the elastic components, inferred to occur between the three plagioclase phases with distinct symmetry (C1>¯, I1>¯, and P1>¯), appear consistent with the nature of the underlying conformation of the framework-linked tetrahedra and the associated structural changes. Measured body wave velocities of plagioclase-rich rocks, reported over the last five decades, are consistent with calculated Hill-averaged velocities using the current moduli. This confirms long-standing speculation that previously reported elastic moduli for plagioclase feldspars are systematically in error. The current results provide greater assurance that the seismic structure of the middle and lower crusts can be accurately estimated on the basis of specified mineral modes, chemistry, and fabric.

  2. Elastic properties of pyrope

    NASA Astrophysics Data System (ADS)

    O'Neill, Bridget; Bass, Jay D.; Rossman, George R.; Geiger, Charles A.; Langer, Klaus

    1991-03-01

    Brillouin spectroscopy was used to measure the single crystal elastic properties of a pure synthetic pyrope and a natural garnet containing 89.9 mol% of the pyrope end member (Mg3Al2Si3O12). The elastic moduli, c ij , of the two samples are entirely consistent and agree with previous estimates of the elastic properties of pyrope based upon the moduli of solid solutions. Our results indicate that the elastic moduli of pyrope end-member are c 11=296.2±0.5, c 12=111.1±0.6, c 44=91.6±0.3, Ks=172.8±0.3, μ=92.0±0.2, all in units of GPa. These results differ by several percent from those reported previously for synthetic pyrope, but are based upon a much larger data set. Although the hydrous components of the two samples from the present study are substantially different, representing both ‘dry’ and ‘saturated’ samples, we find no discernable effect of structurally bound water on the elastic properties. This is due to the small absolute solubility of water in pyrope, as compared with other garnets such as grossular.

  3. Estimating Price Elasticity using Market-Level Appliance Data

    SciTech Connect

    Fujita, K. Sydny

    2015-08-04

    This report provides and update to and expansion upon our 2008 LBNL report “An Analysis of the Price Elasticity of Demand for Appliances,” in which we estimated an average relative price elasticity of -0.34 for major household appliances (Dale and Fujita 2008). Consumer responsiveness to price change is a key component of energy efficiency policy analysis; these policies influence consumer purchases through price both explicitly and implicitly. However, few studies address appliance demand elasticity in the U.S. market and public data sources are generally insufficient for rigorous estimation. Therefore, analysts have relied on a small set of outdated papers focused on limited appliance types, assuming long-term elasticities estimated for other durables (e.g., vehicles) decades ago are applicable to current and future appliance purchasing behavior. We aim to partially rectify this problem in the context of appliance efficiency standards by revisiting our previous analysis, utilizing data released over the last ten years and identifying additional estimates of durable goods price elasticities in the literature. Reviewing the literature, we find the following ranges of market-level price elasticities: -0.14 to -0.42 for appliances; -0.30 to -1.28 for automobiles; -0.47 to -2.55 for other durable goods. Brand price elasticities are substantially higher for these product groups, with most estimates -2.0 or more elastic. Using market-level shipments, sales value, and efficiency level data for 1989-2009, we run various iterations of a log-log regression model, arriving at a recommended range of short run appliance price elasticity between -0.4 and -0.5, with a default value of -0.45.

  4. A comparison of economic demand and conditioned-cued reinstatement of methamphetamine- or food-seeking in rats

    PubMed Central

    Galuska, Chad M.; Banna, Kelly M.; Willse, Lena Vaughn; Yahyavi-Firouz-Abadi, Noushin; See, Ronald E.

    2011-01-01

    The present study examined whether continued access to methamphetamine or food reinforcement changed economic demand for both. The relationship between demand elasticity and cue-induced reinstatement was also determined. Male Long-Evans rats lever-pressed under increasing fixed-ratio requirements for either food pellets or methamphetamine (20 μg/50 μl infusion). For two groups, demand curves were obtained before and after continued access (12 days, 2-hr sessions) to the reinforcer under a fixed-ratio 3 schedule. A third group was given continued access to methamphetamine between determinations of food demand and a fourth group abstained from methamphetamine between determinations. All groups underwent extinction sessions, followed by a cue-induced reinstatement test. Although food demand was less elastic than methamphetamine demand, continued access to methamphetamine shifted the methamphetamine demand curve upward and the food demand curve downward. In some rats, methamphetamine demand also became less elastic. Continued access to food had no effect on food demand. Reinstatement was higher after continued access to methamphetamine relative to food. For methamphetamine, elasticity and reinstatement measures were correlated. We conclude that continued access to methamphetamine – but not food – alters demand in ways suggestive of methamphetamine accruing reinforcing strength. Demand elasticity and reinstatement measures appear to be related indices of drug-seeking. PMID:21597363

  5. A comparison of economic demand and conditioned-cued reinstatement of methamphetamine-seeking or food-seeking in rats.

    PubMed

    Galuska, Chad M; Banna, Kelly M; Willse, Lena Vaughn; Yahyavi-Firouz-Abadi, Noushin; See, Ronald E

    2011-08-01

    This study examined whether continued access to methamphetamine or food reinforcement changed economic demand for both. The relationship between demand elasticity and cue-induced reinstatement was also determined. Male Long-Evans rats were lever pressed under increasing fixed-ratio requirements for either food pellets or methamphetamine (20 μg/50 μl infusion). For two groups, demand curves were obtained before and after continued access (12 days, 2-h sessions) to the reinforcer under a fixed-ratio 3 schedule. A third group was given continued access to methamphetamine between determinations of food demand and a fourth group abstained from methamphetamine between determinations. All groups underwent extinction sessions, followed by a cue-induced reinstatement test. Although food demand was less elastic than methamphetamine demand, continued access to methamphetamine shifted the methamphetamine demand curve upward and the food demand curve downward. In some rats, methamphetamine demand also became less elastic. Continued access to food had no effect on food demand. Reinstatement was higher after continued access to methamphetamine relative to food. For methamphetamine, elasticity and reinstatement measures were correlated. Continued access to methamphetamine, but not food, alters demand in ways suggestive of methamphetamine accruing reinforcing strength. Demand elasticity thus provides a useful measure of abuse liability that may predict future relapse to renewed drug-seeking and drug use.

  6. An elastic second skin

    NASA Astrophysics Data System (ADS)

    Yu, Betty; Kang, Soo-Young; Akthakul, Ariya; Ramadurai, Nithin; Pilkenton, Morgan; Patel, Alpesh; Nashat, Amir; Anderson, Daniel G.; Sakamoto, Fernanda H.; Gilchrest, Barbara A.; Anderson, R. Rox; Langer, Robert

    2016-08-01

    We report the synthesis and application of an elastic, wearable crosslinked polymer layer (XPL) that mimics the properties of normal, youthful skin. XPL is made of a tunable polysiloxane-based material that can be engineered with specific elasticity, contractility, adhesion, tensile strength and occlusivity. XPL can be topically applied, rapidly curing at the skin interface without the need for heat- or light-mediated activation. In a pilot human study, we examined the performance of a prototype XPL that has a tensile modulus matching normal skin responses at low strain (<40%), and that withstands elongations exceeding 250%, elastically recoiling with minimal strain-energy loss on repeated deformation. The application of XPL to the herniated lower eyelid fat pads of 12 subjects resulted in an average 2-grade decrease in herniation appearance in a 5-point severity scale. The XPL platform may offer advanced solutions to compromised skin barrier function, pharmaceutical delivery and wound dressings.

  7. Elastic properties of HMX.

    SciTech Connect

    Sewell, T. D.; Bedrov, D.; Menikoff, Ralph; Smith, G. D.

    2001-01-01

    Atomistic molecular dynamics simulations have been used to calculate isothermal elastic properties for {beta}-, {alpha}-, and {delta}-HMX. The complete elastic tensor for each polymorph was determined at room temperature and pressure via analysis of microscopic strain fluctuations using formalism due to Rahman and Parrinello [J. Chem. Phys. 76,2662 (1982)]. Additionally, the isothermal compression curve was computed for {beta}-HMX for 0 {le} p {le} 10.6 GPa; the bulk modulus K and its pressure derivative K{prime} were obtained from two fitting forms employed previously in experimental studies of the {beta}-HMX equation of state. Overall, the results indicate good agreement between the bulk modulus predicted from the measured and calculated compression curves. The bulk modulus determined directly from the elastic tensor of {beta}-HMX is in significant disagreement with the compression curve-based results. The explanation for this discrepancy is an area of current research.

  8. Elastic constants of calcite

    USGS Publications Warehouse

    Peselnick, L.; Robie, R.A.

    1962-01-01

    The recent measurements of the elastic constants of calcite by Reddy and Subrahmanyam (1960) disagree with the values obtained independently by Voigt (1910) and Bhimasenachar (1945). The present authors, using an ultrasonic pulse technique at 3 Mc and 25??C, determined the elastic constants of calcite using the exact equations governing the wave velocities in the single crystal. The results are C11=13.7, C33=8.11, C44=3.50, C12=4.82, C13=5.68, and C14=-2.00, in units of 1011 dyncm2. Independent checks of several of the elastic constants were made employing other directions and polarizations of the wave velocities. With the exception of C13, these values substantially agree with the data of Voigt and Bhimasenachar. ?? 1962 The American Institute of Physics.

  9. Elastic model of supercoiling.

    PubMed Central

    Benham, C J

    1977-01-01

    An elastic model for the supercoiling of duplex DNA is developed. The simplest assumptions regarding the elastic properties of double-helical DNA (homogeneous, isotropic, of circular cross section, and remaining straight when unstressed) will generate two orders of superhelicity when stressed. Recent experimental results [Brady, G.W., Fein, D.B. & Brumberger, H. (1976) Nature 264, 231-234] suggest that in supercoiled DNA molecules there are regions where two distinct orders of supercoiling arise, as predicted by this model. PMID:267934

  10. Deflation of elastic surfaces

    NASA Astrophysics Data System (ADS)

    Quilliet, Catherine

    2011-03-01

    The deflation of elastic spherical surfaces has been numerically investigated, and show very different types of deformations according the range of elastic parameters, some of them being quantitatively understood through simple theoretical considerations. In particular, the role of the Poisson ratio is closely investigated. This work allowed to retrieve various shapes observed on hollow deformable shells (from colloidal to centimeter scale), on lipid vesicles, or on some simple biological objects. Conversely, it shows how high deformations can tell observers about mechanical properties of a body. Such investigations have been extended to other geometries, in order to provide clues to understand deformations of vegetal or animal tissues.

  11. Demand analysis of tobacco consumption in Malaysia.

    PubMed

    Ross, Hana; Al-Sadat, Nabilla A M

    2007-11-01

    We estimated the price and income elasticity of cigarette demand and the impact of cigarette taxes on cigarette demand and cigarette tax revenue in Malaysia. The data on cigarette consumption, cigarette prices, and public policies between 1990 and 2004 were subjected to a time-series regression analysis applying the error-correction model. The preferred cigarette demand model specification resulted in long-run and short-run price elasticities estimates of -0.57 and -0.08, respectively. Income was positively related to cigarette consumption: A 1% increase in real income increased cigarette consumption by 1.46%. The model predicted that an increase in cigarette excise tax from Malaysian ringgit (RM) 1.60 to RM2.00 per pack would reduce cigarette consumption in Malaysia by 3.37%, or by 806,468,873 cigarettes. This reduction would translate to almost 165 fewer tobacco-related lung cancer deaths per year and a 20.8% increase in the government excise tax revenue. We conclude that taxation is an effective method of reducing cigarette consumption and tobacco-related deaths while increasing revenue for the government of Malaysia.

  12. Slope versus Elasticity and the Burden of Taxation.

    ERIC Educational Resources Information Center

    Graves, Philip E.; And Others

    1996-01-01

    Criticizes the standard presentation, in introductory economics, of the burden of a tax as an application of elasticity. Argues that using the slopes of a supply and demand curve is the simplest and easiest way to clarify tax incidence. Includes three graphs illustrating this approach. (MJP)

  13. Circulation Price Elasticity in the Daily Newspaper Industry.

    ERIC Educational Resources Information Center

    Grotta, Gerald L.; Taylor, Michael Lee

    Pricing of subscriptions and single copies has historically been arbitrary. Evidence indicates that the newspaper industry has tended to overestimate the elasticity of demand for newspaper circulation. This study analyzed price changes, circulation changes, and population changes for all daily newspapers in the United States between 1970 and 1975.…

  14. A Review of Two Studies of Elasticity in Academe.

    ERIC Educational Resources Information Center

    Hoffman, Emily P.

    1986-01-01

    Reviews two elasticity of demand papers in this "Economics of Education Review" issue. Refutes C.F. Chang and H.P. Tuckman's interpretation of college faculty substitution trends, attributing changes in rank distribution to academic hiring and promotion patterns. Affirms G.A. Chressanthis' class standing results and recommendation of a…

  15. Wood supply and demand

    Treesearch

    Peter J. Ince; David B. McKeever

    2011-01-01

    At times in history, there have been concerns that demand for wood (timber) would be greater than the ability to supply it, but that concern has recently dissipated. The wood supply and demand situation has changed because of market transitions, economic downturns, and continued forest growth. This article provides a concise overview of this change as it relates to the...

  16. The Law of Elasticity

    ERIC Educational Resources Information Center

    Cocco, Alberto; Masin, Sergio Cesare

    2010-01-01

    Participants estimated the imagined elongation of a spring while they were imagining that a load was stretching the spring. This elongation turned out to be a multiplicative function of spring length and load weight--a cognitive law analogous to Hooke's law of elasticity. Participants also estimated the total imagined elongation of springs joined…

  17. Elastic and Inelastic Collisions

    ERIC Educational Resources Information Center

    Gluck, Paul

    2010-01-01

    There have been two articles in this journal that described a pair of collision carts used to demonstrate vividly the difference between elastic and inelastic collisions. One cart had a series of washers that were mounted rigidly on a rigid wooden framework, the other had washers mounted on rubber bands stretched across a framework. The rigidly…

  18. Hydrodynamic Elastic Magneto Plastic

    SciTech Connect

    Wilkins, M. L.; Levatin, J. A.

    1985-02-01

    The HEMP code solves the conservation equations of two-dimensional elastic-plastic flow, in plane x-y coordinates or in cylindrical symmetry around the x-axis. Provisions for calculation of fixed boundaries, free surfaces, pistons, and boundary slide planes have been included, along with other special conditions.

  19. Elastic swimming I: Optimization

    NASA Astrophysics Data System (ADS)

    Lauga, Eric; Yu, Tony; Hosoi, Anette

    2006-03-01

    We consider the problem of swimming at low Reynolds number by oscillating an elastic filament in a viscous liquid, as investigated by Wiggins and Goldstein (1998, Phys Rev Lett). In this first part of the study, we characterize the optimal forcing conditions of the swimming strategy and its optimal geometrical characteristics.

  20. Elastic swimming II: Experiments

    NASA Astrophysics Data System (ADS)

    Yu, Tony; Lauga, Eric; Hosoi, Anette

    2006-03-01

    We consider the problem of swimming at low Reynolds number by oscillating an elastic filament in a viscous liquid, as investigated by Wiggins and Goldstein (1998, Phys Rev Lett). In this second part of the study, we present results of a series of experiments characterizing the performance of the propulsive mechanism.

  1. Elastic and Inelastic Collisions

    ERIC Educational Resources Information Center

    Gluck, Paul

    2010-01-01

    There have been two articles in this journal that described a pair of collision carts used to demonstrate vividly the difference between elastic and inelastic collisions. One cart had a series of washers that were mounted rigidly on a rigid wooden framework, the other had washers mounted on rubber bands stretched across a framework. The rigidly…

  2. Demand curves for hypothetical cocaine in cocaine-dependent individuals.

    PubMed

    Bruner, Natalie R; Johnson, Matthew W

    2014-03-01

    Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks, drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated. This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data. Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use. Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and O max (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, P max, were significantly correlated with real-world cocaine use. Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use.

  3. Demand Curves for Hypothetical Cocaine in Cocaine-Dependent Individuals

    PubMed Central

    Bruner, Natalie R.; Johnson, Matthew W.

    2013-01-01

    Rationale Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated. Objectives This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data. Methods Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use. Results Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and Omax (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, Pmax, were significantly correlated with real-world cocaine use. Conclusions Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use. PMID:24217899

  4. Elastic Granular Flows

    NASA Astrophysics Data System (ADS)

    Campbell, Charles

    2006-03-01

    There is no fundamental understanding of the mechanics of granular solids. Partially this is because granular flows have historically been divided into two very distinct flow regimes, (1) the slow, quasistatic regime, in which the bulk friction coefficient is taken to be a material constant, and (2) the fast, rapid-flow regime, where the particles interact collisionally. But slow hopper flow simulations indicate that the bulk friction coefficient is not a constant. Rapidly moving large scale landslide simulations never entered the collisional regime and operate in a separate intermediate flow regime. In other words, most realistic granular flows are not described by either the quasistatic or rapid flow models and it is high time that the field look beyond those early models. This talk will discuss computer simulation studies that draw out the entire flowmap of shearing granular materials, spanning the quasistatic, rapid and the intermediate regimes. The key was to include the elastic properties of the solid material in the set of rheological parameters; in effect, this puts solid properties back into the rheology of granular solids. The solid properties were previously unnecessary in the plasticity and kinetic theory formalisms that respectively form the foundations of the quasistatic and rapid-flow theories. Granular flows can now be divided into two broad categories, the Elastic Regimes, in which the particles are locked in force chains and interact elastically over long duration contact with their neighbors and the Inertial regimes, where the particles have broken free of the force chains. The Elastic regimes can be further subdivided into the Elastic-Quasistatic regime (the old quasistatic regime) and the Elastic-Inertial regime. The Elastic-Inertial regime is the ``new'' regime observed in the landslide simulations, in which the inertially induced stresses are significant compared to the elastically induced stresses. The Inertial regime can also be sub

  5. Nonlinear theoretical formulation of elastic stability criterion of crystal solids

    NASA Astrophysics Data System (ADS)

    Wang, Hao; Li, Mo

    2012-03-01

    An elastic stability criterion is generally formulated based on local elasticity, where the second-order elastic constants of a crystalline system in an arbitrary deformed state are required. While simple in formalism, such a formulation demands extensive computational effort in either an ab initio calculation or an atomistic simulation and often lacks clear physical interpretation. Here, we present a nonlinear theoretical formulation employing higher-order elastic constants beyond the second-order ones; the elastic constants needed in the theory are those at a zero stress state or in any arbitrary deformed state, many of which are now available. We use the published second- and higher-order elastic constants of several cubic crystals, including Au, Al, and Cu, as well as diamond-structure Si, with transcription under different coordinate frames, to test the stability conditions of these crystals under uniaxial and hydrostatic loading. The stability region, ideal strength, and potential bifurcation mode of those cubic crystals under loading are obtained using this theory. The results obtained are in good agreement with the results from the ab initio calculation or embedded atom method. The overall good quality of the results confirms the desired utility of this new approach to predict elastic stability and related properties of crystalline materials without involving intense computation.

  6. The effect of waiting times on demand and supply for elective surgery: Evidence from Italy.

    PubMed

    Riganti, Andrea; Siciliani, Luigi; Fiorio, Carlo V

    2017-09-01

    Waiting times are a major policy concern in publicly funded health systems across OECD countries. Economists have argued that, in the presence of excess demand, waiting times act as nonmonetary prices to bring demand for and supply of health care in equilibrium. Using administrative data disaggregated by region and surgical procedure over 2010-2014 in Italy, we estimate demand and supply elasticities with respect to waiting times. We employ linear regression models with first differences and instrumental variables to deal with endogeneity of waiting times. We find that demand is inelastic to waiting times while supply is more elastic. Estimates of demand elasticity are between -0.15 to -0.24. Our results have implications on the effectiveness of policies aimed at increasing supply and their ability to reduce waiting times. Copyright © 2017 John Wiley & Sons, Ltd.

  7. Demand impact and policy implications from taxing nitrogen fertilizer

    SciTech Connect

    Foltz, J.C.

    1992-12-01

    Recent concern has focused on nitrogen fertilizer as a potential contaminant of groundwater. A demand function for fertilizer was developed using the quantity of fertilizer purchased, corn yield, real price of nitrogen fertilizer, lagged fertilizer purchases, a land value variable and the real price of corn as explanatory variables. Short and long-run price elasticities of demand were estimated to be inelastic. Support was found for the hypothesis that demand for nitrogen fertilizer has become more price inelastic over time. From a policy standpoint, a tax on nitrogen fertilizer may not be the most effective method to reduce consumption.

  8. Price elasticity and medication use: cost sharing across multiple clinical conditions.

    PubMed

    Gatwood, Justin; Gibson, Teresa B; Chernew, Michael E; Farr, Amanda M; Vogtmann, Emily; Fendrick, A Mark

    2014-11-01

    To address the impact that out-of-pocket prices may have on medication use, it is vital to understand how the demand for medications may be affected when patients are faced with changes in the price to acquire treatment and how price responsiveness differs across medication classes.  To examine the impact of cost-sharing changes on the demand for 8 classes of prescription medications. This was a retrospective database analysis of 11,550,363 commercially insured enrollees within the 2005-2009 MarketScan Database. Patient cost sharing, expressed as a price index for each medication class, was the main explanatory variable to examine the price elasticity of demand. Negative binomial fixed effect models were estimated to examine medication fills. The elasticity estimates reflect how use changes over time as a function of changes in copayments. Model estimates revealed that price elasticity of demand ranged from -0.015 to -0.157 within the 8 categories of medications (P  less than  0.01 for 7 of 8 categories). The price elasticity of demand for smoking deterrents was largest (-0.157, P  less than  0.0001), while demand for antiplatelet agents was not responsive to price (P  greater than 0.05). The price elasticity of demand varied considerably by medication class, suggesting that the influence of cost sharing on medication use may be related to characteristics inherent to each medication class or underlying condition.

  9. Efficiency gain from elastic optical networks

    NASA Astrophysics Data System (ADS)

    Morea, Annalisa; Rival, Olivier

    2011-12-01

    We compare the cost-efficiency of optical networks based on mixed datarates (10, 40, 100Gb/s) and datarateelastic technologies. A European backbone network is examined under various traffic assumptions (volume of transported data per demand and total number of demands) to better understand the impact of traffic characteristics on cost-efficiency. Network dimensioning is performed for static and restorable networks (resilient to one-link failure). In this paper we will investigate the trade-offs between price of interfaces, reach and reconfigurability, showing that elastic solutions can be more cost-efficient than mixed-rate solutions because of the better compatibility between different datarates, increased reach of channels and simplified wavelength allocation.

  10. Impact of Energy Demands

    ERIC Educational Resources Information Center

    Cambel, Ali B.

    1970-01-01

    The types of pollutants associated with the process of power production are identified. A nine-point proposal is presented on the ways the increase in power demands might be achieved with the minimum threat to the environment. (PR)

  11. Latin American demand

    SciTech Connect

    1994-12-01

    From Mexico to Argentina, independent power companies are finding great demand for their services in Latin America. But while legal and economic conditions are increasingly favorable, political and financial uncertainties make power development challenging.

  12. Series elastic actuators

    NASA Astrophysics Data System (ADS)

    Williamson, Matthew M.

    1995-01-01

    This thesis presents the design, construction, control and evaluation of a novel for controlled actuator. Traditional force controlled actuators are designed from the premise that 'Stiffer is better'. This approach gives a high bandwidth system, prone to problems of contact instability, noise, and low power density. The actuator presented in this thesis is designed from the premise that 'Stiffness isn't everything'. The actuator, which incorporates a series elastic element, trades off achievable bandwidth for gains in stable, low noise force control, and protection against shock loads. This thesis reviews related work in robot force control, presents theoretical descriptions of the control and expected performance from a series elastic actuator, and describes the design of a test actuator constructed to gather performance data. Finally the performance of the system is evaluated by comparing the performance data to theoretical predictions.

  13. Linear Elastic Waves

    NASA Astrophysics Data System (ADS)

    Revenough, Justin

    Elastic waves propagating in simple media manifest a surprisingly rich collection of phenomena. Although some can't withstand the complexities of Earth's structure, the majority only grow more interesting and more important as remote sensing probes for seismologists studying the planet's interior. To fully mine the information carried to the surface by seismic waves, seismologists must produce accurate models of the waves. Great strides have been made in this regard. Problems that were entirely intractable a decade ago are now routinely solved on inexpensive workstations. The mathematical representations of waves coded into algorithms have grown vastly more sophisticated and are troubled by many fewer approximations, enforced symmetries, and limitations. They are far from straightforward, and seismologists using them need a firm grasp on wave propagation in simple media. Linear Elastic Waves, by applied mathematician John G. Harris, responds to this need.

  14. Demand Response Dispatch Tool

    SciTech Connect

    2012-08-31

    The Demand Response (DR) Dispatch Tool uses price profiles to dispatch demand response resources and create load modifying profiles. These annual profiles are used as inputs to production cost models and regional planning tools (e.g., PROMOD). The tool has been effectively implemented in transmission planning studies conducted by the Western Electricity Coordinating Council via its Transmission Expansion Planning and Policy Committee. The DR Dispatch Tool can properly model the dispatch of DR resources for both reliability and economic conditions.

  15. Elastic plate spallation

    NASA Technical Reports Server (NTRS)

    Oline, L.; Medaglia, J.

    1972-01-01

    The dynamic finite element method was used to investigate elastic stress waves in a plate. Strain displacement and stress strain relations are discussed along with the stiffness and mass matrix. The results of studying point load, and distributed load over small, intermediate, and large radii are reported. The derivation of finite element matrices, and the derivation of lumped and consistent matrices for one dimensional problems with Laplace transfer solutions are included. The computer program JMMSPALL is also included.

  16. Dynamics of elastic systems

    NASA Astrophysics Data System (ADS)

    Sankovich, Vladimir

    1998-12-01

    The goal of this paper is to build a consistent physical theory of the dynamics of the bat-ball interaction. This requires creating realistic models for both the softball bat and the softball. Some of the features of these models are known phenomenologically, from experiments conducted in our laboratory, others will be introduced and computed from first principles here for the first time. Both interacting objects are treated from the viewpoint of the theory of elasticity, and it is shown how a computer can be used to accurately calculate all the relevant characteristics of batball collisions. It is shown also how the major elastic parameters of the material constituting the interior of a softball can be determined using the existing experimental data. These parameters, such as the Young's modulus, the Poisson ratio and the damping coefficient are vital for the accurate description of the ball's dynamics. We are demonstrating how the existing theories of the elastic behavior of solid bars and hollow shells can be augmented to simplify the resulting equations and make the subsequent computer analysis feasible. The standard system of fourth-order PDE's is reduced to a system of the second order, because of the inclusion of the usually ignored effects of the shear forces in the bat.

  17. The Optimal Elastic Flagellum

    NASA Astrophysics Data System (ADS)

    Spagnolie, Saverio; Lauga, Eric

    2009-11-01

    We address the question of optimality for slender swimming bodies or flagella in viscous fluid environments. Our novel approach is to define an energy which includes not only the work performed against the surrounding fluid, but also the energy stored elastically in the bending of the body, the energy stored elastically in internal shearing (such as the relative sliding of microtubules internal to a flagellum), and viscous dissipation due to the presence of an internal fluid. The shape of the optimal periodic planar wave is determined numerically and in some cases analytically which maximizes a related efficiency measure. We find that bending or internal dissipation costs regularize the optimal shape, but elastic shearing costs do not. For bodies of finite length, we show that the number of wavelengths expressed by the body is determined by a competition between bending costs and the work done on the fluid associated with body rotations. The hydrodynamic efficiency is shown to be less sensitive to the morphology than the bending costs, which may help us to better understand the locomotory forms observed in nature.

  18. Trends in the elastic response of binary early transition metal nitrides

    NASA Astrophysics Data System (ADS)

    Holec, David; Friák, Martin; Neugebauer, Jörg; Mayrhofer, Paul H.

    2012-02-01

    Motivated by an increasing demand for coherent data that can be used for selecting materials with properties tailored for specific application requirements, we studied elastic response of nine binary early transition metal nitrides (ScN, TiN, VN, YN, ZrN, NbN, LaN, HfN, and TaN) and AlN. In particular, single-crystal elastic constants, Young's modulus in different crystallographic directions, polycrystalline values of shear and Young's moduli, and the elastic anisotropy factor were calculated. Additionally, we provide estimates of the third order elastic constants for the ten binary nitrides.

  19. Demand for oil and energy in developing countries

    SciTech Connect

    Wolf, C. Jr.; Relles, D.A.; Navarro, J.

    1980-05-01

    How much of the world's oil and energy supply will the non-OPEC less-developed countries (NOLDCs) demand in the next decade. Will their requirements be small and thus fairly insignificant compared with world demand, or large and relatively important. How will world demand be affected by the economic growth of the NOLDCs. In this report, we try to develop some reasonable forecasts of NOLDC energy demands in the next 10 years. Our focus is mainly on the demand for oil, but we also give some attention to the total commercial energy requirements of these countries. We have tried to be explicit about the uncertainties associated with our forecasts, and with the income and price elasticities on which they are based. Finally, we consider the forecasts in terms of their implications for US policies concerning the NOLDCs and suggest areas of future research on NOLDC energy issues.

  20. Community Colleges and Labor Market Conditions: How Does Enrollment Demand Change Relative to Local Unemployment Rates?

    ERIC Educational Resources Information Center

    Hillman, Nicholas W.; Orians, Erica Lee

    2013-01-01

    This study uses fixed-effects panel data techniques to estimate the elasticity of community college enrollment demand relative to local unemployment rates. The findings suggest that community college enrollment demand is counter-cyclical to changes in the labor market, as enrollments rise during periods of weak economic conditions. Using national…

  1. Community Colleges and Labor Market Conditions: How Does Enrollment Demand Change Relative to Local Unemployment Rates?

    ERIC Educational Resources Information Center

    Hillman, Nicholas W.; Orians, Erica Lee

    2013-01-01

    This study uses fixed-effects panel data techniques to estimate the elasticity of community college enrollment demand relative to local unemployment rates. The findings suggest that community college enrollment demand is counter-cyclical to changes in the labor market, as enrollments rise during periods of weak economic conditions. Using national…

  2. Price and the demand for nongroup health insurance.

    PubMed

    Auerbach, David; Ohri, Sabina

    2006-01-01

    In light of recent interest in tax credits and other price-based incentives to stimulate the purchase of insurance, this study estimates the price elasticity of demand for nongroup health insurance for single workers without access to employer-sponsored insurance. Our premium measure explicitly accounts for two components that have not been examined in previous studies: 1) health status, and 2) the effect of state-level premium rating regulations. We estimate a price elasticity of -.59, which, given the low rate of initial coverage in our sample (16.4%), translates to a small effect on the uninsured.

  3. Probabilistic Elastography: Estimating Lung Elasticity

    PubMed Central

    Risholm, Petter; Ross, James; Washko, George R.; Wells, William M.

    2011-01-01

    We formulate registration-based elastography in a probabilistic framework and apply it to study lung elasticity in the presence of emphysematous and fibrotic tissue. The elasticity calculations are based on a Finite Element discretization of a linear elastic biomechanical model. We marginalize over the boundary conditions (deformation) of the biomechanical model to determine the posterior distribution over elasticity parameters. Image similarity is included in the likelihood, an elastic prior is included to constrain the boundary conditions, while a Markov model is used to spatially smooth the inhomogeneous elasticity. We use a Markov Chain Monte Carlo (MCMC) technique to characterize the posterior distribution over elasticity from which we extract the most probable elasticity as well as the uncertainty of this estimate. Even though registration-based lung elastography with inhomogeneous elasticity is challenging due the problem's highly underdetermined nature and the sparse image information available in lung CT, we show promising preliminary results on estimating lung elasticity contrast in the presence of emphysematous and fibrotic tissue. PMID:21761697

  4. Probabilistic elastography: estimating lung elasticity.

    PubMed

    Risholm, Petter; Ross, James; Washko, George R; Wells, William M

    2011-01-01

    We formulate registration-based elastography in a probabilistic framework and apply it to study lung elasticity in the presence of emphysematous and fibrotic tissue. The elasticity calculations are based on a Finite Element discretization of a linear elastic biomechanical model. We marginalize over the boundary conditions (deformation) of the biomechanical model to determine the posterior distribution over elasticity parameters. Image similarity is included in the likelihood, an elastic prior is included to constrain the boundary conditions, while a Markov model is used to spatially smooth the inhomogeneous elasticity. We use a Markov Chain Monte Carlo (MCMC) technique to characterize the posterior distribution over elasticity from which we extract the most probable elasticity as well as the uncertainty of this estimate. Even though registration-based lung elastography with inhomogeneous elasticity is challenging due the problem's highly underdetermined nature and the sparse image information available in lung CT, we show promising preliminary results on estimating lung elasticity contrast in the presence of emphysematous and fibrotic tissue.

  5. Travel Demand Modeling

    SciTech Connect

    Southworth, Frank; Garrow, Dr. Laurie

    2011-01-01

    This chapter describes the principal types of both passenger and freight demand models in use today, providing a brief history of model development supported by references to a number of popular texts on the subject, and directing the reader to papers covering some of the more recent technical developments in the area. Over the past half century a variety of methods have been used to estimate and forecast travel demands, drawing concepts from economic/utility maximization theory, transportation system optimization and spatial interaction theory, using and often combining solution techniques as varied as Box-Jenkins methods, non-linear multivariate regression, non-linear mathematical programming, and agent-based microsimulation.

  6. Impact of population size on market demand under a market economy.

    PubMed

    Li, Y

    1996-01-01

    This article presents an analysis of the relationship between population size and market demand in China. It is argued that a smaller elasticity of a product is related to a greater impact of the size of population on the consumption of such a product. Greater elasticity reduces the impact of population. The impact of population is also mediated by average salary and salary structure. Salary structure affects prices, and prices affect supply and demand, which affect consumption. In a market-oriented economic system, the impact of population size on market demand affects supply and demand and prices. Current market demand reflects the effect of supply and demand in previous periods. Current population size will affect future market demand through prices and supply elasticity. Population changes are slow, and consumption changes are slow. The slowness of the process of change means there is time to adjust production and distribution in order to achieve stability in market supply. Control of price increases and inflation will promote economic growth, social stability, and improvement in China's socialist market economic system. It is argued that the supply of bicycles is elastic. Despite increased investment, labor, and fixed assets, profits will not grow. However the entertainment industry, as well as education, public welfare, urban utilities, noncommercialized housing, and telephones are less elastic. A large consumer population and a smaller supply elasticity result in high costs of installation, which are made higher by the state monopoly. It is argued that in China it is necessary to regulate certain necessities with less market elasticity in order to be consistent with optimum allocation of resources.

  7. Elastic pion Compton scattering

    SciTech Connect

    Kowalewski, R.V.; Berg, D.; Chandlee, C.; Cihangir, S.; Ferbel, T.; Huston, J.; Jensen, T.; Kornberg, R.; Lobkowicz, F.; Ohshima, T.

    1984-03-01

    We present evidence for elastic pion Compton scattering as observed via the Primakoff process on nulcear targets. We find production cross sections for ..pi../sup -/A..--> pi../sup -/..gamma..A on lead and copper of 0.249 +- 0.027 and 0.029 +- 0.006 mb, respectively, in agreement with the values expected from the one-photon-exchange mechanism of 0.268 +- 0.018 and 0.035 +- 0.004 mb in the region of our experimental acceptance. This reaction provides a clean test of the Primakoff formalism.

  8. Design guidance for elastic followup

    SciTech Connect

    Naugle, F.V.

    1983-01-01

    The basic mechanism of elastic followup is discussed in relation to piping design. It is shown how mechanistic insight gained from solutions for a two-bar problem can be used to identify dominant design parameters and to determine appropriate modifications where elastic followup is a potential problem. It is generally recognized that quantitative criteria are needed for elastic followup in the creep range where badly unbalanced lines can pose potential problems. Approaches for criteria development are discussed.

  9. Demanding Divestment from Sudan

    ERIC Educational Resources Information Center

    Asquith, Christina

    2006-01-01

    Bowing to student demands to "stop supporting genocide," the University of California regents voted earlier this year to divest millions of dollars from companies working in the war-torn African nation of Sudan, the first major public university in the nation to take such action. Since student protests on the subject began at Harvard…

  10. 1985 Employment Outlook: Demand.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1984

    1984-01-01

    Findings from an American Chemical Society survey show that the pessimism that characterized the job market in 1983 has given way to a much brighter outlook as employers hire more chemists and chemical engineers. Data from the survey on the supply and demand of chemical professionals are provided and discussed. (JN)

  11. Demands for School Leaders

    ERIC Educational Resources Information Center

    Bradley-Levine, Jill

    2016-01-01

    This article examines the ways that graduate courses in teacher leadership influenced the ways that teachers described the nature of leadership and their role as educational leaders. Using Foster's (1989) four demands for school leaders as a theoretical framework, participants' perceptions are examined to determine how teachers synthesized their…

  12. Demanding Divestment from Sudan

    ERIC Educational Resources Information Center

    Asquith, Christina

    2006-01-01

    Bowing to student demands to "stop supporting genocide," the University of California regents voted earlier this year to divest millions of dollars from companies working in the war-torn African nation of Sudan, the first major public university in the nation to take such action. Since student protests on the subject began at Harvard…

  13. Demand, Growth, and Evolution

    ERIC Educational Resources Information Center

    Hoskins, Barbara

    2011-01-01

    The paradigm shift to engaged and collaborative learning delivered via distance education technologies has been led by practitioners in adult and continuing education. Online and blended courses are experiencing increased demand and continued growth at all levels of higher education, professional development, and K-12 education. Adult and…

  14. Elastic emission polishing

    SciTech Connect

    Loewenthal, M.; Loseke, K.; Dow, T.A.; Scattergood, R.O.

    1988-12-01

    Elastic emission polishing, also called elastic emission machining (EEM), is a process where a stream of abrasive slurry is used to remove material from a substrate and produce damage free surfaces with controlled surface form. It is a noncontacting method utilizing a thick elasto-hydrodynamic film formed between a soft rotating ball and the workpiece to control the flow of the abrasive. An apparatus was built in the Center, which consists of a stationary spindle, a two-axis table for the workpiece, and a pump to circulate the working fluid. The process is controlled by a programmable computer numerical controller (CNC), which presently can operate the spindle speed and movement of the workpiece in one axis only. This apparatus has been used to determine material removal rates on different material samples as a function of time, utilizing zirconium oxide (ZrO{sub 2}) particles suspended in distilled water as the working fluid. By continuing a study of removal rates the process should become predictable, and thus create a new, effective, yet simple tool for ultra-precision mechanical machining of surfaces.

  15. Theory of epithelial elasticity

    NASA Astrophysics Data System (ADS)

    Krajnc, Matej; Ziherl, Primož

    2015-11-01

    We propose an elastic theory of epithelial monolayers based on a two-dimensional discrete model of dropletlike cells characterized by differential surface tensions of their apical, basal, and lateral sides. We show that the effective tissue bending modulus depends on the apicobasal differential tension and changes sign at the transition from the flat to the fold morphology. We discuss three mechanisms that stabilize the finite-wavelength fold structures: Physical constraint on cell geometry, hard-core interaction between non-neighboring cells, and bending elasticity of the basement membrane. We show that the thickness of the monolayer changes along the waveform and thus needs to be considered as a variable rather than a parameter. Next we show that the coupling between the curvature and the thickness is governed by the apicobasal polarity and that the amplitude of thickness modulation along the waveform is proportional to the apicobasal differential tension. This suggests that intracellular stresses can be measured indirectly by observing easily measurable morphometric parameters. We also study the mechanics of three-dimensional structures with cylindrical symmetry.

  16. Demand Responsive Lighting: A Scoping Study

    SciTech Connect

    Rubinstein, Francis; Kiliccote, Sila

    2007-01-03

    increased awareness of the need to standardize on emerging wireless technologies are evidence of this transformation. In addition to increased standardization of digital control protocols controller capabilities, the lighting industry has improved the performance of dimming lighting systems over the last two years. The system efficacy of today's current dimming ballasts is approaching that of non-dimming program start ballasts. The study finds that the benefits of applying digital controls technologies to California's unique commercial buildings market are enormous. If California were to embark on an concerted 20 year program to improve the demand responsiveness and energy efficiency of commercial building lighting systems, the State could avoid adding generation capacity, improve the elasticity of the grid, save Californians billion of dollars in avoided energy charges and significantly reduce greenhouse gas emissions.

  17. Scaling, elasticity, and CLPT

    NASA Technical Reports Server (NTRS)

    Brunelle, Eugene J.

    1994-01-01

    The first few viewgraphs describe the general solution properties of linear elasticity theory which are given by the following two statements: (1) for stress B.C. on S(sub sigma) and zero displacement B.C. on S(sub u) the altered displacements u(sub i)(*) and the actual stresses tau(sub ij) are elastically dependent on Poisson's ratio nu alone: thus the actual displacements are given by u(sub i) = mu(exp -1)u(sub i)(*); and (2) for zero stress B.C. on S(sub sigma) and displacement B.C. on S(sub u) the actual displacements u(sub i) and the altered stresses tau(sub ij)(*) are elastically dependent on Poisson's ratio nu alone: thus the actual stresses are given by tau(sub ij) = E tau(sub ij)(*). The remaining viewgraphs describe the minimum parameter formulation of the general classical laminate theory plate problem as follows: The general CLT plate problem is expressed as a 3 x 3 system of differential equations in the displacements u, v, and w. The eighteen (six each) A(sub ij), B(sub ij), and D(sub ij) system coefficients are ply-weighted sums of the transformed reduced stiffnesses (bar-Q(sub ij))(sub k); the (bar-Q(sub ij))(sub k) in turn depend on six reduced stiffnesses (Q(sub ij))(sub k) and the material and geometry properties of the k(sup th) layer. This paper develops a method for redefining the system coefficients, the displacement components (u,v,w), and the position components (x,y) such that a minimum parameter formulation is possible. The pivotal steps in this method are (1) the reduction of (bar-Q(sub ij))(sub k) dependencies to just two constants Q(*) = (Q(12) + 2Q(66))/(Q(11)Q(22))(exp 1/2) and F(*) - (Q(22)/Q(11))(exp 1/2) in terms of ply-independent reference values Q(sub ij); (2) the reduction of the remaining portions of the A, B, and D coefficients to nondimensional ply-weighted sums (with 0 to 1 ranges) that are independent of Q(*) and F(*); and (3) the introduction of simple coordinate stretchings for u, v, w and x,y such that the process is

  18. A unique formulation of elastic airplane longitudinal equations of motion

    NASA Technical Reports Server (NTRS)

    Swaim, R. L.; Fullman, D. G.

    1976-01-01

    Control-configured vehicle technology has increased the demand for detailed analysis of dynamic stability and control, handling and ride qualities, and control system dynamics at early stages of preliminary design. An approximate, but reasonably accurate, set of equations of motion are needed for these early analyses. Such a formulation is developed for the longitudinal dynamics of elastic airplanes. It makes use of only rigid-body aerodynamic stability derivatives in formulating the forces and moments due to elastic motion. Verification of accuracy using data for the B-1 airplane shows very good agreement. Frequencies and damping ratios of the coupled modes corresponding to complex roots of the characteristic equations agree closely with four symmetric elastic modes included.

  19. ORNL rural electric-energy-demand forecasting model

    SciTech Connect

    Maddigan, R.J.; Chern, W.S.; Gallagher, C.A.; Holcomb, B.D.; Cobbs, J.C.

    1981-09-01

    The development of a forecasting model of annual electrical-energy sales for the Rural Electrification Administration (REA) borrowers is discussed. The Oak Ridge National Laboratory, Rural Electric Energy Demand (ORNL-REED) model highlights the unique features of rural electricity demand by empirically examining the customers of the electric cooperatives. The model is used to forecast annual electricity sales by state and sector for the next twenty years. REED is a nonlinear, simultaneous-equation econometric model. It consists of submodels for the residential, commercial, industrial and irrigation sectors. The construction of a data base which reflects the cooperatives' service areas is described. The nine structural equations of REED were estimated using pooled, cross-section, time-series data for the period 1969 through 1977 for five regions. In general, the residential and commercial own-price demand elasticities are lower for the rural cooperatives than they are for the rest of the electric utility industry. However, the elasticities estimated by REED for the industrial sector tend to be higher than those estimated for the total state. The price elasticities of demand for irrigation are greater than the other sectors, indicating that the farmer is especially sensitive to changing electricity prices. The forecasts of the cooperatives' electricity demand are estimated for six sets of input assumptions, These projections give a range of total demand growth between 5.4% and 6.6% depending upon the demographic and fuel-price assumptions, compared to the 9.8% growth the cooperatives experienced between 1969 and 1977. The projected growth figures vary across states and sectors.

  20. Demand surge following earthquakes

    USGS Publications Warehouse

    Olsen, Anna H.

    2012-01-01

    Demand surge is understood to be a socio-economic phenomenon where repair costs for the same damage are higher after large- versus small-scale natural disasters. It has reportedly increased monetary losses by 20 to 50%. In previous work, a model for the increased costs of reconstruction labor and materials was developed for hurricanes in the Southeast United States. The model showed that labor cost increases, rather than the material component, drove the total repair cost increases, and this finding could be extended to earthquakes. A study of past large-scale disasters suggested that there may be additional explanations for demand surge. Two such explanations specific to earthquakes are the exclusion of insurance coverage for earthquake damage and possible concurrent causation of damage from an earthquake followed by fire or tsunami. Additional research into these aspects might provide a better explanation for increased monetary losses after large- vs. small-scale earthquakes.

  1. Elastic Shapes of DNA

    NASA Astrophysics Data System (ADS)

    Fain, Boris; Rudnick, Joseph

    1997-03-01

    Short segments of DNA assume shapes that minimize their elastic energy. Modeling of the various mechanisms involving the molecule - replication, transcription, packaging, etc. - requires a description of the conformations of DNA under constraints. We develop a formalism that obtains analytic expressions for shape, link, twist and extension of a segment subject to sufficient number of constraints. We apply our technique to two particular cases: a) Stretched twisted linear DNA. This is an interesting test for our formalism, especially in light of recent experiments(Strick T.R., Allemand J.-F., Bensimon A., Croquette V. Science) 271 1835-1837, (1996). The molecule remains extended until a critical twist is reached, at which point it undergoes a plectonemic transition. b) Closed circular DNA. Describing the shapes of such molecules has been an outstanding problem for some time. We obtain a family of curves classified by their deviation in link from the plain circle.

  2. MODELING THE DEMAND FOR E85 IN THE UNITED STATES

    SciTech Connect

    Liu, Changzheng; Greene, David L

    2013-10-01

    How demand for E85 might evolve in the future in response to changing economics and policies is an important subject to include in the National Energy Modeling System (NEMS). This report summarizes a study to develop an E85 choice model for NEMS. Using the most recent data from the states of Minnesota, North Dakota, and Iowa, this study estimates a logit model that represents E85 choice as a function of prices of E10 and E85, as well as fuel availability of E85 relative to gasoline. Using more recent data than previous studies allows a better estimation of non-fleet demand and indicates that the price elasticity of E85 choice appears to be higher than previously estimated. Based on the results of the econometric analysis, a model for projecting E85 demand at the regional level is specified. In testing, the model produced plausible predictions of US E85 demand to 2040.

  3. The optimal elastic flagellum

    NASA Astrophysics Data System (ADS)

    Spagnolie, Saverio E.; Lauga, Eric

    2010-03-01

    Motile eukaryotic cells propel themselves in viscous fluids by passing waves of bending deformation down their flagella. An infinitely long flagellum achieves a hydrodynamically optimal low-Reynolds number locomotion when the angle between its local tangent and the swimming direction remains constant along its length. Optimal flagella therefore adopt the shape of a helix in three dimensions (smooth) and that of a sawtooth in two dimensions (nonsmooth). Physically, biological organisms (or engineered microswimmers) must expend internal energy in order to produce the waves of deformation responsible for the motion. Here we propose a physically motivated derivation of the optimal flagellum shape. We determine analytically and numerically the shape of the flagellar wave which leads to the fastest swimming for a given appropriately defined energetic expenditure. Our novel approach is to define an energy which includes not only the work against the surrounding fluid, but also (1) the energy stored elastically in the bending of the flagellum, (2) the energy stored elastically in the internal sliding of the polymeric filaments which are responsible for the generation of the bending waves (microtubules), and (3) the viscous dissipation due to the presence of an internal fluid. This approach regularizes the optimal sawtooth shape for two-dimensional deformation at the expense of a small loss in hydrodynamic efficiency. The optimal waveforms of finite-size flagella are shown to depend on a competition between rotational motions and bending costs, and we observe a surprising bias toward half-integer wave numbers. Their final hydrodynamic efficiencies are above 6%, significantly larger than those of swimming cells, therefore indicating available room for further biological tuning.

  4. Elastic model of dry friction

    SciTech Connect

    Larkin, A. I.; Khmelnitskii, D. E.

    2013-09-15

    Friction of elastic bodies is connected with the passing through the metastable states that arise at the contact of surfaces rubbing against each other. Three models are considered that give rise to the metastable states. Friction forces and their dependence on the pressure are calculated. In Appendix A, the contact problem of elasticity theory is solved with adhesion taken into account.

  5. The First Law of Elasticity

    ERIC Educational Resources Information Center

    Girill, T. R.

    1972-01-01

    The Boyle-Mariotte gas law was formulated in terms of pneumatic springs," subsumed by Hooke under his own stress-strain relation, and generally regarded as a law of elasticity. The subsequent development of Boyle's principle and elasticity provide thought-provoking test cases for Kuhn's notations of paradigm and puzzle solving in physics.…

  6. Valve designed with elastic seat

    NASA Technical Reports Server (NTRS)

    Mac Glashan, W. F., Jr.

    1965-01-01

    Absolute valve closure is accomplished by a machined valve with an axially annular channel which changes the outlet passage into a thin tubular elastic seat member with a retainer backup ring. The elasticity of the seat provides tight conformity to ball irregularity.

  7. PAGOSA Sample Problem. Elastic Precursor

    SciTech Connect

    Weseloh, Wayne N.; Clancy, Sean Patrick

    2016-02-03

    A PAGOSA simulation of a flyer plate impact which produces an elastic precursor wave is examined. The simulation is compared to an analytic theory for the Mie-Grüneisen equation of state and an elastic-perfectly-plastic strength model.

  8. The First Law of Elasticity

    ERIC Educational Resources Information Center

    Girill, T. R.

    1972-01-01

    The Boyle-Mariotte gas law was formulated in terms of pneumatic springs," subsumed by Hooke under his own stress-strain relation, and generally regarded as a law of elasticity. The subsequent development of Boyle's principle and elasticity provide thought-provoking test cases for Kuhn's notations of paradigm and puzzle solving in physics.…

  9. Tip velocity tracking control for elastic manipulators

    NASA Astrophysics Data System (ADS)

    Sever, Manfred Dieter Martin

    A unique approach to tip velocity control of an elastic robotic manipulator is presented. This method has potential application in teleoperation control and in applications where the trajectory is generated in real-time. Control is effected by reducing the tip velocity tracking error between the desired tip velocity and the measured tip velocity. Thus, in teleoperation, the concept of dead reckoning is used, so that while the manipulator's desired tip velocity is specified, the goal is for the tip to follow a path, leading toward a desired terminal position. This is done by concentrating the controller's effort on the manipulator tip while allowing the manipulator's links to deform., The controller utilizes a gain scheduling scheme to arrive at an appropriate feedback law. The control algorithm is implemented using a parallel-processing scheme on a multiprocessor system which consists of INMOS TransputersRTM . Experimental results are obtained using Radius, the Space Robotics Laboratory Facility at the University of Toronto Institute for Aerospace Studies. Radius was designed to serve specifically as a test-bed for the development and evaluation of control methods for elastic manipulators. For the present work Radius is configured as a two-link manipulator with both links structurally flexible. One of the trajectories used for the simulations and experiment is a square, which is quite difficult for an elastic manipulator to execute. This box trajectory is more demanding than trajectories typically executed by Canadarm and so link elasticity becomes an important consideration. The effect of elasticity is demonstrated using an independent joint PD controller. In simulation, excellent tip velocity tracking was achieved using the proposed controller. In the experiment, reasonable accuracy in following the desired tip path was attained, however, disturbances, mainly a result of unmodeled joint dynamics, caused degraded performance. The controller may be improved by

  10. Accounting for Water Insecurity in Modeling Domestic Water Demand

    NASA Astrophysics Data System (ADS)

    Galaitsis, S. E.; Huber-lee, A. T.; Vogel, R. M.; Naumova, E.

    2013-12-01

    Water demand management uses price elasticity estimates to predict consumer demand in relation to water pricing changes, but studies have shown that many additional factors effect water consumption. Development scholars document the need for water security, however, much of the water security literature focuses on broad policies which can influence water demand. Previous domestic water demand studies have not considered how water security can affect a population's consumption behavior. This study is the first to model the influence of water insecurity on water demand. A subjective indicator scale measuring water insecurity among consumers in the Palestinian West Bank is developed and included as a variable to explore how perceptions of control, or lack thereof, impact consumption behavior and resulting estimates of price elasticity. A multivariate regression model demonstrates the significance of a water insecurity variable for data sets encompassing disparate water access. When accounting for insecurity, the R-squaed value improves and the marginal price a household is willing to pay becomes a significant predictor for the household quantity consumption. The model denotes that, with all other variables held equal, a household will buy more water when the users are more water insecure. Though the reasons behind this trend require further study, the findings suggest broad policy implications by demonstrating that water distribution practices in scarcity conditions can promote consumer welfare and efficient water use.

  11. Elasticity of Flowing Soap films

    NASA Astrophysics Data System (ADS)

    Kim, Ildoo; Mandre, Shreyas

    2016-11-01

    The robustness of soap films and bubbles manifests their mechanical stability. The single most important factor underlying the mechanical stability of soap films is its elasticity. Non-destructive measurement of the elasticity in these films has been cumbersome, because of its flowing nature. Here we provide a convenient, reproducible, and non-destructive method for measuring the elasticity by generating and inspecting Marangoni waves. Our method is based on generating an oblique shock by inserting a thin cylindrical obstacle in the flowing film, and converting the measured the shock angle to elasticity. Using this method, we find a constant value for the elasticity of 22 dyne/cm in the commonly used range of film widths, thicknesses or flow rates, implying that the surface of the film is chemically saturated with soap molecules.

  12. Factor Demand Theory Under Perfect Competition, Monopoly, and Monopsony,

    DTIC Science & Technology

    1974-10-01

    MC(p 1,. . . , p , q *) = 0 (13) and -~~~~~~~ > 0. Holding p constant and different iat ing Eq. (13) as an f implicit function yields -~~~\\I...Charles , and C. E. Ferguson , “Factor Demand Elasticity under Monopoly and Monopsony ,” Economica , Vol. 40, May 19-73, pp. 180— 186. -• [5] Sato

  13. Renewable Energy Resources Portfolio Optimization in the Presence of Demand Response

    SciTech Connect

    Behboodi, Sahand; Chassin, David P.; Crawford, Curran; Djilali, Ned

    2016-01-15

    In this paper we introduce a simple cost model of renewable integration and demand response that can be used to determine the optimal mix of generation and demand response resources. The model includes production cost, demand elasticity, uncertainty costs, capacity expansion costs, retirement and mothballing costs, and wind variability impacts to determine the hourly cost and revenue of electricity delivery. The model is tested on the 2024 planning case for British Columbia and we find that cost is minimized with about 31% renewable generation. We also find that demand responsive does not have a significant impact on cost at the hourly level. The results suggest that the optimal level of renewable resource is not sensitive to a carbon tax or demand elasticity, but it is highly sensitive to the renewable resource installation cost.

  14. Oxide nanoelectronics on demand.

    PubMed

    Cen, Cheng; Thiel, Stefan; Mannhart, Jochen; Levy, Jeremy

    2009-02-20

    Electronic confinement at nanoscale dimensions remains a central means of science and technology. We demonstrate nanoscale lateral confinement of a quasi-two-dimensional electron gas at a lanthanum aluminate-strontium titanate interface. Control of this confinement using an atomic force microscope lithography technique enabled us to create tunnel junctions and field-effect transistors with characteristic dimensions as small as 2 nanometers. These electronic devices can be modified or erased without the need for complex lithographic procedures. Our on-demand nanoelectronics fabrication platform has the potential for widespread technological application.

  15. Dividends with Demand Response

    SciTech Connect

    Kintner-Meyer, Michael CW; Goldman, Charles; Sezgen, O.; Pratt, D.

    2003-10-31

    To assist facility managers in assessing whether and to what extent they should participate in demand response programs offered by ISOs, we introduce a systematic process by which a curtailment supply curve can be developed that integrates costs and other program provisions and features. This curtailment supply curve functions as bid curve, which allows the facility manager to incrementally offer load to the market under terms and conditions acceptable to the customer. We applied this load curtailment assessment process to a stylized example of an office building, using programs offered by NYISO to provide detail and realism.

  16. Naturalistic assessment of demand for cigarettes, snus, and nicotine gum.

    PubMed

    Stein, Jeffrey S; Wilson, A George; Koffarnus, Mikhail N; Judd, Michael C; Bickel, Warren K

    2017-01-01

    Behavioral economic measures of demand provide estimates of tobacco product abuse liability and may predict effects of policy-related price regulation on consumption of existing and emerging tobacco products. In the present study, we examined demand for snus, a smokeless tobacco product, in comparison to both cigarettes and medicinal nicotine. We used both a naturalistic method in which participants purchased these products for use outside the laboratory, as well as laboratory-based self-administration procedures. Cigarette smokers (N = 42) used an experimental income to purchase their usual brand of cigarettes and either snus or gum (only one product available per session) across a range of prices, while receiving all products they purchased from one randomly selected price. In a separate portion of the study, participants self-administered these products during laboratory-based, progressive ratio sessions. Demand elasticity (sensitivity of purchasing to price) was significantly greater for snus than cigarettes. Elasticity for gum was intermediate between snus and cigarettes but was not significantly different than either. Demand intensity (purchasing unconstrained by price) was significantly lower for gum compared to cigarettes, with no significant difference observed between snus and cigarettes. Results of the laboratory-based, progressive ratio sessions were generally discordant with measures of demand elasticity, with significantly higher "breakpoints" for cigarettes compared to gum and no significant differences between other study products. Moreover, breakpoints and product purchasing were generally uncorrelated across tasks. Under naturalistic conditions, snus appears more sensitive to price manipulation than either cigarettes or nicotine gum in existing smokers.

  17. Elasticity of crystalline molecular explosives

    DOE PAGES

    Hooks, Daniel E.; Ramos, Kyle J.; Bolme, C. A.; ...

    2015-04-14

    Crystalline molecular explosives are key components of engineered explosive formulations. In precision applications a high degree of consistency and predictability is desired under a range of conditions to a variety of stimuli. Prediction of behaviors from mechanical response and failure to detonation initiation and detonation performance of the material is linked to accurate knowledge of the material structure and first stage of deformation: elasticity. The elastic response of pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and cyclotetramethylene tetranitramine (HMX), including aspects of material and measurement variability, and computational methods are described in detail. Experimental determinations of elastic tensors are compared, andmore » an evaluation of sources of error is presented. Furthermore, computed elastic constants are also compared for these materials and for triaminotrinitrobenzene (TATB), for which there are no measurements.« less

  18. Elasticity of crystalline molecular explosives

    SciTech Connect

    Hooks, Daniel E.; Ramos, Kyle J.; Bolme, C. A.; Cawkwell, Marc J.

    2015-04-14

    Crystalline molecular explosives are key components of engineered explosive formulations. In precision applications a high degree of consistency and predictability is desired under a range of conditions to a variety of stimuli. Prediction of behaviors from mechanical response and failure to detonation initiation and detonation performance of the material is linked to accurate knowledge of the material structure and first stage of deformation: elasticity. The elastic response of pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and cyclotetramethylene tetranitramine (HMX), including aspects of material and measurement variability, and computational methods are described in detail. Experimental determinations of elastic tensors are compared, and an evaluation of sources of error is presented. Furthermore, computed elastic constants are also compared for these materials and for triaminotrinitrobenzene (TATB), for which there are no measurements.

  19. Measuring How Elastic Arteries Function.

    ERIC Educational Resources Information Center

    DeMont, M. Edwin; MacGillivray, Patrick S.; Davison, Ian G.; McConnell, Colin J.

    1997-01-01

    Describes a procedure used to measure force and pressure in elastic arteries. Discusses the physics of the procedure and recommends the use of bovine arteries. Explains the preparation of the arteries for the procedure. (DDR)

  20. Measuring How Elastic Arteries Function.

    ERIC Educational Resources Information Center

    DeMont, M. Edwin; MacGillivray, Patrick S.; Davison, Ian G.; McConnell, Colin J.

    1997-01-01

    Describes a procedure used to measure force and pressure in elastic arteries. Discusses the physics of the procedure and recommends the use of bovine arteries. Explains the preparation of the arteries for the procedure. (DDR)

  1. Elastic protectors for ultrasound injection

    SciTech Connect

    Barkhatov, V.A.; Nesterova, L.A.

    1995-07-01

    A new material has been developed for elastic protectors on ultrasonic probes: sonar rubber. This combines low ultrasonic absorption, high strength, and wear resistance, and so the rubber can be used in sensor designs.

  2. Flame resistant elastic elastomeric fibers

    NASA Technical Reports Server (NTRS)

    Howarth, J. T.; Massucco, A. A.

    1972-01-01

    Development of materials to improve flame resistance of elastic elastomeric fibers is discussed. Two approaches, synthesis of polyether based urethanes and modification of synthesized urethanes with flame ratardant additives, are described. Specific applications of both techniques are presented.

  3. Hilbert complexes of nonlinear elasticity

    NASA Astrophysics Data System (ADS)

    Angoshtari, Arzhang; Yavari, Arash

    2016-12-01

    We introduce some Hilbert complexes involving second-order tensors on flat compact manifolds with boundary that describe the kinematics and the kinetics of motion in nonlinear elasticity. We then use the general framework of Hilbert complexes to write Hodge-type and Helmholtz-type orthogonal decompositions for second-order tensors. As some applications of these decompositions in nonlinear elasticity, we study the strain compatibility equations of linear and nonlinear elasticity in the presence of Dirichlet boundary conditions and the existence of stress functions on non-contractible bodies. As an application of these Hilbert complexes in computational mechanics, we briefly discuss the derivation of a new class of mixed finite element methods for nonlinear elasticity.

  4. Elastic waves in quasiperiodic structures

    NASA Astrophysics Data System (ADS)

    Velasco, V. R.; Zárate, J. E.

    2001-08-01

    We study the transverse and sagittal elastic waves in different quasiperiodic structures by means of the full transfer-matrix technique and surface Green-function matching method. The quasiperiodic structures follow Fibonacci, Thue-Morse and Rudin-Shapiro sequences, respectively. We consider finite structures having stress-free bounding surfaces and different generation orders, including up to more than 1000 interfaces. We obtain the dispersion relations for elastic waves and spatial localization of the different modes. The fragmentation of the spectrum for different sequences is evident for intermediate generation orders, in the case of transverse elastic waves, whereas, for sagittal elastic waves, higher generation orders are needed to show clearly the spectrum fragmentation. The results of Fibonacci and Thue-Morse sequences exhibit similarities not present in the results of Rudin-Shapiro sequences.

  5. Elastic Properties of Mantle Minerals

    NASA Astrophysics Data System (ADS)

    Duffy, T. S.; Stan, C. V.

    2012-12-01

    The most direct information about the interior structure of the Earth comes from seismic wave velocities. Interpretation of seismic data requires an understanding of how sound velocities and elastic properties of minerals vary with pressure, temperature, crystal structure, and composition as well as the role of anelasticity, melts, etc. More generally, elastic moduli are important for understanding many solid-state phenomena including mechanical stability, interatomic interactions, material strength, compressibility, and phase transition mechanisms. The database of mineral elasticity measurements has been growing rapidly in recent years. In this work, we report initial results of an ongoing survey of our current knowledge of mineral elasticity at both ambient conditions and high pressures and temperatures. The analysis is selective, emphasizing single crystal measurements but also incorporating polycrystalline measurements and volume compression data as appropriate. The goal is to synthesize our current understanding of mineral elasticity in terms of structure and composition, and to identify the major remaining needs for experimental and theoretical work. Clinopyroxenes (Cpx) provide an example of our approach. A wide range of clinopyroxene compositions are found geologically and Mg-, Ca-, and Na-rich clinopyroxenes are expected to be important components in the upper mantle. The single-crystal elastic properties of a number of endmember Cpx compositions have been measured and these exhibit a range of ~25% in shear velocity. Those with monovalent cations (spodumene, jadeite) in the M2 site exhibit the highest velocities while Fe-rich (hendenbergit, acmite) compositions have the lowest velocities. The effects on velocity due to a wide range of chemical substitutions can be defined, but there are important discrepancies and omissions in the database. New measurements of omphacites, intermediate diopside-hedenbergite compositions, aegerine/acmite, augite, etc. are

  6. An empirical analysis of cigarette demand in Argentina

    PubMed Central

    Martinez, Eugenio; Mejia, Raul; Pérez-Stable, Eliseo J

    2014-01-01

    Objective To estimate the long-term and short-term effects on cigarette demand in Argentina based on changes in cigarette price and income per person >14 years old. Method Public data from the Ministry of Economics and Production were analysed based on monthly time series data between 1994 and 2010. The econometric analysis used cigarette consumption per person >14 years of age as the dependent variable and the real income per person >14 years old and the real average price of cigarettes as independent variables. Empirical analyses were done to verify the order of integration of the variables, to test for cointegration to capture the long-term effects and to capture the short-term dynamics of the variables. Results The demand for cigarettes in Argentina was affected by changes in real income and the real average price of cigarettes. The long-term income elasticity was equal to 0.43, while the own-price elasticity was equal to −0.31, indicating a 10% increase in the growth of real income led to an increase in cigarette consumption of 4.3% and a 10% increase in the price produced a fall of 3.1% in cigarette consumption. The vector error correction model estimated that the short-term income elasticity was 0.25 and the short-term own-price elasticity of cigarette demand was −0.15. A simulation exercise showed that increasing the price of cigarettes by 110% would maximise revenues and result in a potentially large decrease in total cigarette consumption. Conclusion Econometric analyses of cigarette consumption and their relationship with cigarette price and income can provide valuable information for developing cigarette price policy. PMID:23760657

  7. An empirical analysis of cigarette demand in Argentina.

    PubMed

    Martinez, Eugenio; Mejia, Raul; Pérez-Stable, Eliseo J

    2015-01-01

    To estimate the long-term and short-term effects on cigarette demand in Argentina based on changes in cigarette price and income per person >14 years old. Public data from the Ministry of Economics and Production were analysed based on monthly time series data between 1994 and 2010. The econometric analysis used cigarette consumption per person >14 years of age as the dependent variable and the real income per person >14 years old and the real average price of cigarettes as independent variables. Empirical analyses were done to verify the order of integration of the variables, to test for cointegration to capture the long-term effects and to capture the short-term dynamics of the variables. The demand for cigarettes in Argentina was affected by changes in real income and the real average price of cigarettes. The long-term income elasticity was equal to 0.43, while the own-price elasticity was equal to -0.31, indicating a 10% increase in the growth of real income led to an increase in cigarette consumption of 4.3% and a 10% increase in the price produced a fall of 3.1% in cigarette consumption. The vector error correction model estimated that the short-term income elasticity was 0.25 and the short-term own-price elasticity of cigarette demand was -0.15. A simulation exercise showed that increasing the price of cigarettes by 110% would maximise revenues and result in a potentially large decrease in total cigarette consumption. Econometric analyses of cigarette consumption and their relationship with cigarette price and income can provide valuable information for developing cigarette price policy. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  8. Grower demand for sensor-controlled irrigation

    NASA Astrophysics Data System (ADS)

    Lichtenberg, Erik; Majsztrik, John; Saavoss, Monica

    2015-01-01

    Water scarcity is likely to increase in the coming years, making improvements in irrigation efficiency increasingly important. An emerging technology that promises to increase irrigation efficiency substantially is a wireless irrigation sensor network that uploads sensor data into irrigation management software, creating an integrated system that allows real-time monitoring and control of moisture status that has been shown in experimental settings to reduce irrigation costs, lower plant loss rates, shorten production times, decrease pesticide application, and increase yield, quality, and profit. We use an original survey to investigate likely initial acceptance, ceiling adoption rates, and profitability of this new sensor network technology in the nursery and greenhouse industry. We find that adoption rates for a base system and demand for expansion components are decreasing in price, as expected. The price elasticity of the probability of adoption suggests that sensor networks are likely to diffuse at a rate somewhat greater than that of drip irrigation. Adoption rates for a base system and demand for expansion components are increasing in specialization in ornamental production: growers earning greater shares of revenue from greenhouse and nursery operations are willing to pay more for a base system and are willing to purchase larger numbers of expansion components at any given price. We estimate that growers who are willing to purchase a sensor network expect investment in this technology to generate significant profit, consistent with findings from experimental studies.

  9. Demand for ground transportation fuel and pricing policy in Asian tigers: A comparative study of Korea and Taiwan

    SciTech Connect

    Banaszak, S.; Chakravorty, U.; Leung, P.S.

    1999-07-01

    This paper examines the demand for gasoline and diesel in the ground transportation sectors of South Korea and Taiwan, comparing the effects of their different pricing policies and stages of economic growth. To account for substitutability between the two fuels, the model proposed here uses a system of equations estimated simultaneously with time-series data from 1973--1992. Results yield demand elasticities that confirm previous research showing that oil product demand is generally price inelastic, which income elasticities (reflecting a longer period of economic growth than previous studies in the Asian region) are lower than those previously reported. The estimated demand functions are then used to generate forecasts for both countries and, in particular, for an assumed reduction in a 180% tax on gasoline in Korea. Forecasted increases in demand by the year 2010 range from 40 to 180%, while the tax analysis suggests that Korea's pricing policy has reduced total demand and promoted the use of diesel over gasoline.

  10. An analysis of short haul air passenger demand, volume 2

    NASA Technical Reports Server (NTRS)

    Blumer, T. P.; Swan, W. M.

    1978-01-01

    Several demand models for short haul air travel are proposed and calibrated on pooled data. The models are designed to predict demand and analyze some of the motivating phenomena behind demand generation. In particular, an attempt is made to include the effects of competing modes and of alternate destinations. The results support three conclusions: (1) the auto mode is the air mode's major competitor; (2) trip time is an overriding factor in intermodal competition, with air fare at its present level appearing unimportant to the typical short haul air traveler; and (3) distance appears to underly several demand generating phenomena, and therefore, must be considered very carefully to any intercity demand model. It may be the cause of the wide range of fare elasticities reported by researchers over the past 15 years. A behavioral demand model is proposed and calibrated. It combines the travel generating effects of income and population, the effects of modal split, the sensitivity of travel to price and time, and the effect of alternative destinations satisfying the trip purpose.

  11. Elastic wavefield migration and tomography

    NASA Astrophysics Data System (ADS)

    Duan, Yuting

    Wavefield migration and tomography are well-developed under the acoustic assumption; however, multicomponent recorded seismic data include shear waves (S-modes) in addition to the compressional waves (P-modes). Constructing multicomponent wavefields and considering multiparameter model properties make it possible to utilize information provided by various wave modes, and this information allows for better characterization of the subsurface. In my thesis, I apply popular wavefield imaging and tomography to elastic media, and propose methods to address challenges posed by elastic multicomponent wavefields and multiparameter models. The key novelty of my research consists of new elastic imaging conditions, which generate elastic images with improved qualities and clear physical meaning. Moreover, I demonstrate an elastic wavefield tomography method to obtain realistic elastic models which benefits elastic migration. Migration techniques, including conventional RTM, extended RTM, and least-squares RTM (LSRTM), provide images of subsurface structures. I propose one imaging condition that computes potential images (PP, PS, SP, and SS). This imaging condition exploits pure P- and S-modes obtained by Helmholtz decomposition and corrects for the polarity reversal in PS and SP images. Using this imaging condition, I propose methods for conventional RTM and extended RTM. The extended imaging condition makes it possible to compute angle gathers for converted waves. The amplitudes of the scalar images indicate reflectivities, which can be used for amplitude verse offset (AVO) analysis; however, this imaging condition requires knowledge of the geologic dip. I propose a second imaging condition that computes perturbation images, i.e., P and S velocity perturbations. Because these images correspond to perturbations to material properties that are angle-independent, they do not have polarity reversals; therefore, they do not need dip information for polarity correction. I use this

  12. Demand Forecasting and Revenue Requirements, with Implications for Consideration in British Columbia,

    DTIC Science & Technology

    1983-05-01

    Econometric Study of Electricity Demand by Manufacturing Industries," NUREG /CR-11358, Oak Ridge, Tennessee: Energy Division, Oak Ridge National...Load for States and Utility Service Areas," NUREG /CR-2692, ORNL/TM- 7947, Oak Ridge, Tennessee: Energy Division, Oak Ridge National Laboratory, May...1982. Just, Richard E. and Chang, Hui S., "A Varying Elasticity Model of Electricity Demand with Given Appliance Saturation," NUREG /CR- 1956, ORNL/ NUREG

  13. Elastic actuation for legged locomotion

    NASA Astrophysics Data System (ADS)

    Cao, Chongjing; Conn, Andrew

    2017-04-01

    The inherent elasticity of dielectric elastomer actuators (DEAs) gives this technology great potential in energy efficient locomotion applications. In this work, a modular double cone DEA is developed with reduced manufacturing and maintenance time costs. This actuator can lift 45 g of mass (5 times its own weight) while producing a stroke of 10.4 mm (23.6% its height). The contribution of the elastic energy stored in antagonistic DEA membranes to the mechanical work output is experimentally investigated by adding delay into the DEA driving voltage. Increasing the delay time in actuation voltage and hence reducing the duty cycle is found to increase the amount of elastic energy being recovered but an upper limit is also noticed. The DEA is then applied to a three-segment leg that is able to move up and down by 17.9 mm (9% its initial height), which demonstrates the feasibility of utilizing this DEA design in legged locomotion.

  14. Photoacoustic elastic oscillation and characterization.

    PubMed

    Gao, Fei; Feng, Xiaohua; Zheng, Yuanjin

    2015-08-10

    Photoacoustic imaging and sensing have been studied extensively to probe the optical absorption of biological tissue in multiple scales ranging from large organs to small molecules. However, its elastic oscillation characterization is rarely studied and has been an untapped area to be explored. In literature, photoacoustic signal induced by pulsed laser is commonly modelled as a bipolar "N-shape" pulse from an optical absorber. In this paper, the photoacoustic damped oscillation is predicted and modelled by an equivalent mass-spring system by treating the optical absorber as an elastic oscillator. The photoacoustic simulation incorporating the proposed oscillation model shows better agreement with the measured signal from an elastic phantom, than conventional photoacoustic simulation model. More interestingly, the photoacoustic damping oscillation effect could potentially be a useful characterization approach to evaluate biological tissue's mechanical properties in terms of relaxation time, peak number and ratio beyond optical absorption only, which is experimentally demonstrated in this paper.

  15. An integrated communications demand model

    NASA Astrophysics Data System (ADS)

    Doubleday, C. F.

    1980-11-01

    A computer model of communications demand is being developed to permit dynamic simulations of the long-term evolution of demand for communications media in the U.K. to be made under alternative assumptions about social, economic and technological trends in British Telecom's business environment. The context and objectives of the project and the potential uses of the model are reviewed, and four key concepts in the demand for communications media, around which the model is being structured are discussed: (1) the generation of communications demand; (2) substitution between media; (3) technological convergence; and (4) competition. Two outline perspectives on the model itself are given.

  16. Thermal Fluctuations and Rubber Elasticity

    NASA Astrophysics Data System (ADS)

    Xing, Xiangjun; Goldbart, Paul M.; Radzihovsky, Leo

    2007-02-01

    The effects of thermal elastic fluctuations in rubbery materials are examined. It is shown that, due to their interplay with the incompressibility constraint, these fluctuations qualitatively modify the large-deformation stress-strain relation, compared to that of classical rubber elasticity. To leading order, this mechanism provides a simple and generic explanation for the peak structure of Mooney-Rivlin stress-strain relation and shows good agreement with experiments. It also leads to the prediction of a phonon correlation function that depends on the external deformation.

  17. Thermal fluctuations and rubber elasticity.

    PubMed

    Xing, Xiangjun; Goldbart, Paul M; Radzihovsky, Leo

    2007-02-16

    The effects of thermal elastic fluctuations in rubbery materials are examined. It is shown that, due to their interplay with the incompressibility constraint, these fluctuations qualitatively modify the large-deformation stress-strain relation, compared to that of classical rubber elasticity. To leading order, this mechanism provides a simple and generic explanation for the peak structure of Mooney-Rivlin stress-strain relation and shows good agreement with experiments. It also leads to the prediction of a phonon correlation function that depends on the external deformation.

  18. Electron-H Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.

    2003-01-01

    Precision calculations for e^{-}-H and e^{-}-He^{+} for S-wave scattering in the elastic region have been carried out using the optical potential approach. This formalism is now extended to e^{-}-H P-wave scattering in the elastic region. The scattering equations are solved by the non-iterative method. Phase shifts are calculated using Hylleraas-type correlation functions up to 84 terms. Results are rigorous lower bounds to the exact phase shifts and they are compared to those obtained in previous calculations.

  19. Cellular Uptake of Elastic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Yi, Xin; Shi, Xinghua; Gao, Huajian

    2011-08-01

    A fundamental understanding of cell-nanomaterial interaction is of essential importance to nanomedicine and safe applications of nanotechnology. Here we investigate the adhesive wrapping of a soft elastic vesicle by a lipid membrane. We show that there exist a maximum of five distinct wrapping phases based on the stability of full wrapping, partial wrapping, and no wrapping states. The wrapping phases depend on the vesicle size, adhesion energy, surface tension of membrane, and bending rigidity ratio between vesicle and membrane. These results are of immediate interest to the study of vesicular transport and endocytosis or phagocytosis of elastic particles into cells.

  20. Shape memory polymer network with thermally distinct elasticity and plasticity

    PubMed Central

    Zhao, Qian; Zou, Weike; Luo, Yingwu; Xie, Tao

    2016-01-01

    Stimuli-responsive materials with sophisticated yet controllable shape-changing behaviors are highly desirable for real-world device applications. Among various shape-changing materials, the elastic nature of shape memory polymers allows fixation of temporary shapes that can recover on demand, whereas polymers with exchangeable bonds can undergo permanent shape change via plasticity. We integrate the elasticity and plasticity into a single polymer network. Rational molecular design allows these two opposite behaviors to be realized at different temperature ranges without any overlap. By exploring the cumulative nature of the plasticity, we demonstrate easy manipulation of highly complex shapes that is otherwise extremely challenging. The dynamic shape-changing behavior paves a new way for fabricating geometrically complex multifunctional devices. PMID:26824077

  1. Cheaper by the Dozen: Using Sibling Discounts at Catholic Schools to Estimate the Price Elasticity of Private School Attendance. NBER Working Paper No. 15461

    ERIC Educational Resources Information Center

    Dynarski, Susan; Gruber, Jonathan; Li, Danielle

    2009-01-01

    The effect of vouchers on sorting between private and public schools depends upon the price elasticity of demand for private schooling. Estimating this elasticity is empirically challenging because prices and quantities are jointly determined in the market for private schooling. We exploit a unique and previously undocumented source of variation…

  2. Cheaper by the Dozen: Using Sibling Discounts at Catholic Schools to Estimate the Price Elasticity of Private School Attendance. NBER Working Paper No. 15461

    ERIC Educational Resources Information Center

    Dynarski, Susan; Gruber, Jonathan; Li, Danielle

    2009-01-01

    The effect of vouchers on sorting between private and public schools depends upon the price elasticity of demand for private schooling. Estimating this elasticity is empirically challenging because prices and quantities are jointly determined in the market for private schooling. We exploit a unique and previously undocumented source of variation…

  3. Demand for outpatient healthcare: empirical findings from rural India.

    PubMed

    Sarma, Sisira

    2009-01-01

    Price, income and health status are likely to affect the demand for healthcare in developing countries, and their quantitative effects are unclear in the literature. Some studies report that prices are not important determinants, while others conclude that prices are important determinants of the demand for healthcare. Knowledge of the extent to which price, income and health status affect the demand for healthcare is crucial for the design of effective health policy in developing countries. To examine the role of monetary and non-monetary price, income, and a variety of individual- and household-specific characteristics on the demand for healthcare in rural India. Utilizing micro data from the 52nd round of India's National Sample Survey, a variable choice set based on geographical location, price, income and the severity of illness was constructed to reflect the underlying true choice-generating process in rural India. Nested multinomial logit models were estimated and simulations with respect to prices and income were conducted to estimate price and income elasticities. Contrary to many earlier studies on the demand for healthcare in developing countries, it was found that prices and income were statistically significant determinants of the choice of healthcare provider by individuals in rural India. Demand for healthcare was found to be price and income inelastic, corroborating the findings from other developing countries. Distance to formal healthcare facilities negatively affected the demand for outpatient healthcare, an effect that was mitigated as access to transportation improved. Age, sex, healthy days, educational status of the household members and the number of children and adults living in the household also affected the choice of healthcare provider in rural India. After controlling for a number of sociodemographic factors, it was found that prices, income and distance are statistically significant determinants of the provider chosen by individuals

  4. Supply and demand for wood as a source of energy in Zambia: An econometric analysis

    SciTech Connect

    Mupimpila, C.

    1993-01-01

    This study examines the status of biomass energy in Zambia. In its current usage, the concept of biomass energy often implies woodfuel because woodfuel is the main biomass energy. This study develops an econometric model of household woodfuel demand and also evaluates the supply of woodfuel in Zambia. The study finds that there are significant sectoral differences in woodfuel demand between the rural and urban sectors. In the rural sector, inflation is by far the most significant determinant of household woodfuel demand. The coefficients on inflation are statistically significant at better than the one percent level and also have expected positive signs. In the urban sector, inflation is again by far the most significant determinant of woodfuel demand. However, in the urban sector, household income and woodfuel price are also significant determinants of demand. The coefficients on inflation, household income, and woodfuel price are all significant at better than the one percent level and have expected signs. The income elasticity of woodfuel demand is positive, suggesting that in the short-run, woodfuel is a normal good. However, the elasticity of woodfuel demand with respect to growth in investment is negative, indicating that long-run structural change in the economy reduces woodfuel demand.

  5. Demand Activated Manufacturing Architecture

    SciTech Connect

    Bender, T.R.; Zimmerman, J.J.

    2001-02-07

    Honeywell Federal Manufacturing & Technologies (FM&T) engineers John Zimmerman and Tom Bender directed separate projects within this CRADA. This Project Accomplishments Summary contains their reports independently. Zimmerman: In 1998 Honeywell FM&T partnered with the Demand Activated Manufacturing Architecture (DAMA) Cooperative Business Management Program to pilot the Supply Chain Integration Planning Prototype (SCIP). At the time, FM&T was developing an enterprise-wide supply chain management prototype called the Integrated Programmatic Scheduling System (IPSS) to improve the DOE's Nuclear Weapons Complex (NWC) supply chain. In the CRADA partnership, FM&T provided the IPSS technical and business infrastructure as a test bed for SCIP technology, and this would provide FM&T the opportunity to evaluate SCIP as the central schedule engine and decision support tool for IPSS. FM&T agreed to do the bulk of the work for piloting SCIP. In support of that aim, DAMA needed specific DOE Defense Programs opportunities to prove the value of its supply chain architecture and tools. In this partnership, FM&T teamed with Sandia National Labs (SNL), Division 6534, the other DAMA partner and developer of SCIP. FM&T tested SCIP in 1998 and 1999. Testing ended in 1999 when DAMA CRADA funding for FM&T ceased. Before entering the partnership, FM&T discovered that the DAMA SCIP technology had an array of applications in strategic, tactical, and operational planning and scheduling. At the time, FM&T planned to improve its supply chain performance by modernizing the NWC-wide planning and scheduling business processes and tools. The modernization took the form of a distributed client-server planning and scheduling system (IPSS) for planners and schedulers to use throughout the NWC on desktops through an off-the-shelf WEB browser. The planning and scheduling process within the NWC then, and today, is a labor-intensive paper-based method that plans and schedules more than 8,000 shipped parts

  6. Nonresident Enrollment Demand in Public Higher Education: An Analysis at National, State, and Institutional Levels

    ERIC Educational Resources Information Center

    Zhang, Liang

    2007-01-01

    This article estimates the standard demand equations for nonresident students using national, state, and institutional level data. The national-level analysis reveals a near-unitary price elasticity, but increases in nonresident tuition and fees do not decrease nonresident enrollment. Finally, results from the institutional level of analysis…

  7. An analysis of at-home demand for ice cream in the United States.

    PubMed

    Davis, C G; Blayney, D P; Yen, S T; Cooper, J

    2009-12-01

    Ice cream has been manufactured commercially in the United States since the middle of the 19th century. Ice cream and frozen dessert products comprise an important and relatively stable component of the United States dairy industry. As with many other dairy products, ice cream is differentiated in several dimensions. A censored translog demand system model was employed to analyze purchases of 3 ice cream product categories. The objective of this study was to determine the effect that changes in retail prices and consumer income have on at-home ice cream consumption. The analysis was based on Nielsen 2005 home scan retail data and used marital status, age, race, education, female employment status, and location in the estimations of aggregate demand elasticities. Results revealed that price and consumer income were the main determinants of demand for ice cream products. Calculated own-price elasticities indicated relatively elastic responses by consumers for all categories except for compensated bulk ice cream. All expenditure elasticities were inelastic except for bulk ice cream, and most of the ice cream categories were substitutes. Ongoing efforts to examine consumer demand for these products will assist milk producers, dairy processors and manufacturers, and dairy marketers as they face changing consumer responses to food and diet issues.

  8. Demand for Primary Schooling in Rural Mali: Should User Fees Be Increased?

    ERIC Educational Resources Information Center

    Birdsall, Nancy; Orivel, Francois

    1996-01-01

    Assesses the effect of school fees on primary school attendance, using household and school survey data from rural Mali. Estimates elasticity of demand regarding fees and compares it with effects of distance and quality on enrollment. User fees can provide a partial solution to the quality/enrollment problem, but cannot solve the distance problem.…

  9. Nonresident Enrollment Demand in Public Higher Education: An Analysis at National, State, and Institutional Levels

    ERIC Educational Resources Information Center

    Zhang, Liang

    2007-01-01

    This article estimates the standard demand equations for nonresident students using national, state, and institutional level data. The national-level analysis reveals a near-unitary price elasticity, but increases in nonresident tuition and fees do not decrease nonresident enrollment. Finally, results from the institutional level of analysis…

  10. Demand for pneumococcal vaccination under subsidy program for the elderly in Japan.

    PubMed

    Kondo, Masahide; Yamamura, Mariko; Hoshi, Shu-Ling; Okubo, Ichiro

    2012-09-12

    Vaccination programs often organize subsidies and public relations in order to obtain high uptake rates and coverage. However, effects of subsidies and public relations have not been studied well in the literature. In this study, the demand function of pneumococcal vaccination among the elderly in Japan is estimated, incorporating effects of public relations and subsidy. Using a data from a questionnaire survey sent to municipalities, the varying and constant elasticity models were applied to estimate the demand function. The response variable is the uptake rate. Explanatory variables are: subsidy supported shot price, operating years of the program, target population size for vaccination, shot location intensity, income and various public relations tools. The best model is selected by c-AIC, and varying and constant price elasticities are calculated from estimation results. The vaccine uptake rate and the shot price have a negative relation. From the results of varying price elasticity, the demand for vaccination is elastic at municipalities with a shot price higher than 3,708 JPY (35.7 USD). Effects of public relations on the uptake rate are not found. It can be suggested that municipalities with a shot price higher than 3,708 JPY (35.7 USD) could subsidize more and reduce price to increase the demand for vaccination. Effects of public relations are not confirmed in this study, probably due to measurement errors of variables used for public relations, and studies at micro level exploring individual's response to public relations would be required.

  11. CAREER GUIDE FOR DEMAND OCCUPATIONS.

    ERIC Educational Resources Information Center

    LEE, E.R.; WELCH, JOHN L.

    THIS PUBLICATION UPDATES THE "CAREER GUIDE FOR DEMAND OCCUPATIONS" PUBLISHED IN 1959 AND PROVIDES COUNSELORS WITH INFORMATION ABOUT OCCUPATIONS IN DEMAND IN MANY AREAS WHICH REQUIRE PREEMPLOYMENT TRAINING. IT PRESENTS, IN COLUMN FORM, THE EDUCATION AND OTHER TRAINING USUALLY REQUIRED BY EMPLOYERS, HIGH SCHOOL SUBJECTS OF PARTICULAR PERTINENCE TO…

  12. CAREER GUIDE FOR DEMAND OCCUPATIONS.

    ERIC Educational Resources Information Center

    LEE, E.R.; WELCH, JOHN L.

    THIS PUBLICATION UPDATES THE "CAREER GUIDE FOR DEMAND OCCUPATIONS" PUBLISHED IN 1959 AND PROVIDES COUNSELORS WITH INFORMATION ABOUT OCCUPATIONS IN DEMAND IN MANY AREAS WHICH REQUIRE PREEMPLOYMENT TRAINING. IT PRESENTS, IN COLUMN FORM, THE EDUCATION AND OTHER TRAINING USUALLY REQUIRED BY EMPLOYERS, HIGH SCHOOL SUBJECTS OF PARTICULAR PERTINENCE TO…

  13. China, India demand cushions prices

    SciTech Connect

    Boyle, M.

    2006-11-15

    Despite the hopes of coal consumers, coal prices did not plummet in 2006 as demand stayed firm. China and India's growing economies, coupled with solid supply-demand fundamentals in North America and Europe, and highly volatile prices for alternatives are likely to keep physical coal prices from wide swings in the coming year.

  14. Harnessing the power of demand

    SciTech Connect

    Sheffrin, Anjali; Yoshimura, Henry; LaPlante, David; Neenan, Bernard

    2008-03-15

    Demand response can provide a series of economic services to the market and also provide ''insurance value'' under low-likelihood, but high-impact circumstances in which grid reliablity is enhanced. Here is how ISOs and RTOs are fostering demand response within wholesale electricity markets. (author)

  15. Societal Demands on the Curriculum.

    ERIC Educational Resources Information Center

    Froese, Elmer E.

    Canada's national educational system elicits diverse curricular demands and requires discreet, sensitive responses. In spite of perennial funding shortfalls, Canada's schools have been remarkably successful in meeting those demands. During and after the 1960s, educational change came as a result of two very strong sets of expectations. One broad…

  16. Robustness Elasticity in Complex Networks

    PubMed Central

    Matisziw, Timothy C.; Grubesic, Tony H.; Guo, Junyu

    2012-01-01

    Network robustness refers to a network’s resilience to stress or damage. Given that most networks are inherently dynamic, with changing topology, loads, and operational states, their robustness is also likely subject to change. However, in most analyses of network structure, it is assumed that interaction among nodes has no effect on robustness. To investigate the hypothesis that network robustness is not sensitive or elastic to the level of interaction (or flow) among network nodes, this paper explores the impacts of network disruption, namely arc deletion, over a temporal sequence of observed nodal interactions for a large Internet backbone system. In particular, a mathematical programming approach is used to identify exact bounds on robustness to arc deletion for each epoch of nodal interaction. Elasticity of the identified bounds relative to the magnitude of arc deletion is assessed. Results indicate that system robustness can be highly elastic to spatial and temporal variations in nodal interactions within complex systems. Further, the presence of this elasticity provides evidence that a failure to account for nodal interaction can confound characterizations of complex networked systems. PMID:22808060

  17. Elastic modes and their computation

    SciTech Connect

    Hedstrom, G.W.

    1995-04-01

    In this note we summarize the theory of modes in stratified elastic media, and we discuss some of the considerations necessary to achieve reliable numerical computations. We also point out the consequences of the fact that the corresponding eigenvalue problem is not selfadjoint. 14 refs.

  18. Duration of an Elastic Collision

    ERIC Educational Resources Information Center

    de Izarra, Charles

    2012-01-01

    With a pedagogical goal, this paper deals with a study of the duration of an elastic collision of an inflatable spherical ball on a planar surface suitable for undergraduate studies. First, the force generated by the deformed spherical ball is obtained under assumptions that are discussed. The study of the motion of the spherical ball colliding…

  19. [Use of elastic compression stockings].

    PubMed

    Kallestrup, Lisbeth; Søgaard, Tine; Schjødt, Inge; Grove, Erik Lerkevang

    2014-08-04

    Post-thrombotic syndrome (PTS) is caused by venous insufficiency and is a frequent complication of deep venous thrombosis. Patients with PTS have reduced quality of life and an increased risk of recurrent deep venous thrombosis. Importantly, the risk of PTS is halved by the use of elastic compression stockings. This review outlines important practical aspects related to correct clinical use of these stockings.

  20. Duration of an Elastic Collision

    ERIC Educational Resources Information Center

    de Izarra, Charles

    2012-01-01

    With a pedagogical goal, this paper deals with a study of the duration of an elastic collision of an inflatable spherical ball on a planar surface suitable for undergraduate studies. First, the force generated by the deformed spherical ball is obtained under assumptions that are discussed. The study of the motion of the spherical ball colliding…

  1. HEMP. Hydrodynamic Elastic Magneto Plastic

    SciTech Connect

    Wilkins, M.L.; Levatin, J.A.

    1985-02-01

    The HEMP code solves the conservation equations of two-dimensional elastic-plastic flow, in plane x-y coordinates or in cylindrical symmetry around the x-axis. Provisions for calculation of fixed boundaries, free surfaces, pistons, and boundary slide planes have been included, along with other special conditions.

  2. Pilot Study of Debt Elasticity

    ERIC Educational Resources Information Center

    Greiner, Keith; Girardi, Tony

    2006-01-01

    This report examines the relationship between student loan debt and the manner in which that debt is described. It focuses on three forms of description: (1) monthly payments, (2) total debt, and (3) income after graduation. The authors used the term elasticity to describe the relationship between consumers' college choices and the retention…

  3. Demand Response for Ancillary Services

    SciTech Connect

    Alkadi, Nasr E; Starke, Michael R

    2013-01-01

    Many demand response resources are technically capable of providing ancillary services. In some cases, they can provide superior response to generators, as the curtailment of load is typically much faster than ramping thermal and hydropower plants. Analysis and quantification of demand response resources providing ancillary services is necessary to understand the resources economic value and impact on the power system. Methodologies used to study grid integration of variable generation can be adapted to the study of demand response. In the present work, we describe and illustrate a methodology to construct detailed temporal and spatial representations of the demand response resource and to examine how to incorporate those resources into power system models. In addition, the paper outlines ways to evaluate barriers to implementation. We demonstrate how the combination of these three analyses can be used to translate the technical potential for demand response providing ancillary services into a realizable potential.

  4. Automated Demand Response and Commissioning

    SciTech Connect

    Piette, Mary Ann; Watson, David S.; Motegi, Naoya; Bourassa, Norman

    2005-04-01

    This paper describes the results from the second season of research to develop and evaluate the performance of new Automated Demand Response (Auto-DR) hardware and software technology in large facilities. Demand Response (DR) is a set of activities to reduce or shift electricity use to improve the electric grid reliability and manage electricity costs. Fully-Automated Demand Response does not involve human intervention, but is initiated at a home, building, or facility through receipt of an external communications signal. We refer to this as Auto-DR. The evaluation of the control and communications must be properly configured and pass through a set of test stages: Readiness, Approval, Price Client/Price Server Communication, Internet Gateway/Internet Relay Communication, Control of Equipment, and DR Shed Effectiveness. New commissioning tests are needed for such systems to improve connecting demand responsive building systems to the electric grid demand response systems.

  5. Price elasticity estimates for tobacco products in India.

    PubMed

    John, Rijo M

    2008-05-01

    The tax base of tobacco in India is heavily dependent on about 14% of tobacco users, who smoke cigarettes. Non-cigarette tobacco products accounting for 85% of the tobacco consumption contributes only 15% of the total tobacco taxes. Though taxation is an important tool to regulate consumption of tobacco, there have been no estimates of price elasticities for different tobacco products in India to date, which can guide tax policy on tobacco. This paper, for the first time in India, examines the price elasticity of demand for bidis, cigarettes and leaf tobacco at the national level using a representative cross-section of households. This study found that own-price elasticity estimates of different tobacco products in India ranged between -0.4 to -0.9, with bidis (an indigenous hand-rolled smoked tobacco preparation in India) and leaf tobacco having elasticities close to unity. Cigarettes were the least price elastic of all. With some assumptions, it is shown that the tax on bidis can be increased to Rs. 100 per 1000 sticks compared with the current Rs. 14 and the tax on an average cigarette can be increased to Rs. 3.5 per stick without any fear of losing revenue. The paper argues that the current system of taxing cigarettes in India based on the presence of filters and the length of cigarettes has no justification on health grounds, and should be abolished, if reducing tobacco consumption and the consequent disease burden is one of the objectives of tobacco taxation policy. It also argues that attempts to regulate tobacco use without effecting significant tax increases on bidis may not produce desired results.

  6. Price Elasticity Estimates for Tobacco Products in India

    PubMed Central

    John, Rijo M

    2009-01-01

    The tax base of tobacco in India is heavily dependent on about 14% of tobacco users, who smoke cigarettes. Non-cigarette tobacco products accounting for 85% of the tobacco consumption contributes only 15% of the total tobacco taxes. Though taxation is an important tool to regulate consumption of tobacco, there have been no estimates of price elasticities for different tobacco products in India to date, which can guide tax policy on tobacco. This paper, for the first time in India, examines the price elasticity of demand for bidis, cigarettes and leaf tobacco at the national level using a representative cross-section of households. This study found that own-price elasticity estimates of different tobacco products in India ranged between −0.4 to −0.9, with bidis (an indigenous hand-rolled smoked tobacco preparation in India) and leaf tobacco having elasticities close to unity. Cigarettes were the least price elastic of all. With some assumptions, it is shown that the tax on bidis can be increased to Rs. 100 per 1000 sticks compared with the current Rs. 14 and the tax on an average cigarette can be increased to Rs. 3.5 per stick without any fear of losing revenue. The paper argues that the current system of taxing cigarettes in India based on the presence of filters and the length of cigarettes has no justification on health grounds, and should be abolished, if reducing tobacco consumption and the consequent disease burden is one of the objectives of tobacco taxation policy. It also argues that attempts to regulate tobacco use without effecting significant tax increases on bidis may not produce desired results. PMID:18424474

  7. Elastic And Plastic Deformations In Butt Welds

    NASA Technical Reports Server (NTRS)

    Verderaime, V.

    1992-01-01

    Report presents study of mathematical modeling of stresses and strains, reaching beyond limits of elasticity, in bars and plates. Study oriented toward development of capability to predict stresses and resulting elastic and plastic strains in butt welds.

  8. The demand for physician services. Evidence from a natural experiment.

    PubMed

    Cockx, Bart; Brasseur, Carine

    2003-11-01

    This study exploits a natural experiment in Belgium to estimate the effect of copayment increases on the demand for physician services. It shows how a differences-in-differences (DD) estimator of the price effects can be decomposed into effects induced by the common average proportional price increase (income effects) and by the change in relative prices (substitution effects). The price elasticity of a uniform proportional price increase is relatively small (-0.13 for men and -0.03 for women). Substitution effects are large, especially for women, but imprecisely estimated. Despite the substantial price increases, the efficiency gain of the reform, if any, is modest.

  9. On the anisotropic elastic properties of hydroxyapatite.

    NASA Technical Reports Server (NTRS)

    Katz, J. L.; Ukraincik, K.

    1971-01-01

    Experimental measurements of the isotropic elastic moduli on polycrystalline specimens of hydroxyapatite and fluorapatite are compared with elastic constants measured directly from single crystals of fluorapatite in order to derive a set of pseudo single crystal elastic constants for hydroxyapatite. The stiffness coefficients thus derived are given. The anisotropic and isotropic elastic properties are then computed and compared with similar properties derived from experimental observations of the anisotropic behavior of bone.

  10. 21 CFR 880.5075 - Elastic bandage.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Elastic bandage. 880.5075 Section 880.5075 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.5075 Elastic bandage. (a) Identification. An elastic bandage is a device consisting of either a...

  11. 21 CFR 880.5075 - Elastic bandage.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Elastic bandage. 880.5075 Section 880.5075 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.5075 Elastic bandage. (a) Identification. An elastic bandage is a device consisting of either a...

  12. 21 CFR 880.5075 - Elastic bandage.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Elastic bandage. 880.5075 Section 880.5075 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.5075 Elastic bandage. (a) Identification. An elastic bandage is a device consisting of either a...

  13. Modeling the Demand for Cocaine

    DTIC Science & Technology

    1994-01-01

    the Demand for Cocaine Susan S. Everingham C. Peter Rydell Pre~redfor the Office of NatinalDrug Control Policy United States Army DRUG POLICY...Demand for Cocaine . 60 50- sm 40- squared 30- delta prevalence 20- 10- 0.2 0 0.15 0.15 󈧄 b C; 0 i Sum squared delta 0.2 prevalence 0.195 EQ 50-50 0,19...model of the demand for cocaine that was fit to 20 years of data on the current cocaine epidemic in the United States. It also describes the analysis

  14. A strain-consistent elastic plate model with surface elasticity

    NASA Astrophysics Data System (ADS)

    Ru, C. Q.

    2016-03-01

    A strain-consistent elastic plate model is formulated in which both initial surface tension and the induced residual stress are treated as finite values, and the exactly same strain expressions are consistently employed for both the surface and the bulk plate. Different than most of previous related models which follow the original Gurtin-Murdoch model and include some non-strain displacement gradient terms (which cannot be expressed in terms of the surface infinitesimal strains or the von Karman-type strains) in the surface stress-strain relations, the present model does not include any non-strain displacement gradient terms in the surface stress-strain relations. For a free elastic plate with in-plane movable edges, the present model predicts that initial surface tension exactly cancels out the induced residual compressive stress. On the other hand, if all edges are in-plane immovable, residual stress cannot develop in the plate and the initial surface tension causes a tensile net membrane force. In addition, the present model predicts that initial surface tension reduces the effective bending rigidity of the plate, while this reduction does not depend on Poisson ratio. In particular, self-buckling of a free elastic plate under tensile surface tension cannot occur unless the effective bending rigidity of plate vanishes or becomes negative.

  15. Bulk strain solitons as a tool for determination of the third order elastic moduli of composite materials

    NASA Astrophysics Data System (ADS)

    Semenova, I. V.; Belashov, A. V.; Garbuzov, F. E.; Samsonov, A. M.; Semenov, A. A.

    2017-06-01

    We demonstrate an alternative approach to determination of the third order elastic moduli of materials based on registration of nonlinear bulk strain waves in three basic structural waveguides (rod, plate and shell) and further calculation of the Murnaghan moduli from the recorded wave parameters via simple algebra. These elastic moduli are available in literature for a limited number of materials and are measured with considerable errors, that evidences a demand in novel approaches to their determination.

  16. An annual quasidifference approach to water price elasticity

    NASA Astrophysics Data System (ADS)

    Bell, David R.; Griffin, Ronald C.

    2008-08-01

    The preferred price specification for retail water demand estimation has not been fully settled by prior literature. Empirical consistency of price indices is necessary to enable testing of competing specifications. Available methods of unbiasing the price index are summarized here. Using original rate information from several hundred Texas utilities, new indices of marginal and average price change are constructed. Marginal water price change is shown to explain consumption variation better than average water price change, based on standard information criteria. Annual change in quantity consumed per month is estimated with differences in climate variables and the new quasidifference marginal price index. As expected, the annual price elasticity of demand is found to vary with daily high and low temperatures and the frequency of precipitation.

  17. Residential water demand with endogenous pricing: The Canadian Case

    NASA Astrophysics Data System (ADS)

    Reynaud, Arnaud; Renzetti, Steven; Villeneuve, Michel

    2005-11-01

    In this paper, we show that the rate structure endogeneity may result in a misspecification of the residential water demand function. We propose to solve this endogeneity problem by estimating a probabilistic model describing how water rates are chosen by local communities. This model is estimated on a sample of Canadian local communities. We first show that the pricing structure choice reflects efficiency considerations, equity concerns, and, in some cases, a strategy of price discrimination across consumers by Canadian communities. Hence estimating the residential water demand without taking into account the pricing structures' endogeneity leads to a biased estimation of price and income elasticities. We also demonstrate that the pricing structure per se plays a significant role in influencing price responsiveness of Canadian residential consumers.

  18. Is the demand for alcoholic beverages in developing countries sensitive to price? Evidence from China.

    PubMed

    Tian, Guoqiang; Liu, Feng

    2011-06-01

    Economic literature in developed countries suggests that demand for alcoholic beverages is sensitive to price, with an estimated price elasticity ranging from -0.38 for beer and -0.7 for liquor. However, few studies have been conducted in developing countries. We employ a large individual-level dataset in China to estimate the effects of price on alcohol demand. Using the data from China Health and Nutrition Survey for the years 1993, 1997, 2000, 2004 and 2006, we estimate two-part models of alcohol demand. Results show the price elasticity is virtually zero for beer and only -0.12 for liquor, which is far smaller than those derived from developed countries. Separate regressions by gender reveals the results are mainly driven by men. The central implication of this study is, while alcohol tax increases can raise government revenue, it alone is not an effective policy to reduce alcohol related problems in China.

  19. Analysis of cigarette demand in Argentina: the impact of price changes on consumption and government revenues.

    PubMed

    Rodríguez-Iglesias, Germán; Schoj, Verónica; Chaloupka, Frank; Champagne, Beatriz; González-Rozada, Martín

    2017-01-01

    To estimate cigarette demand and to simulate a tax policy targeted to reduce tobacco consumption. Demand was estimated using a vector error correction model. Simulation exercises present the impact of a tax increase on consumption and revenues. Changes in real income and the real price of cigarettes affect the demand for cigarettes in Argentina. The long term price elasticity is 0.279 (a 10% increase in real prices reduces cigarette consumption by 2.79% per quarter) and the long term income elasticity is 0.411 (a 10% increase in real income raises consumption by 4.11% per quarter). Even in a conservative scenario, simulations show that increasing the price of cigarettes by 100% using excise taxes would maximize revenues and reduce cigarette consumption. There is sufficient room to increase taxes, reducing cigarette consumption, while still increasing tax revenues.

  20. Cigarette demand is responsive to higher prices: findings from a survey of University students in Jordan.

    PubMed

    Sweis, Nadia J; Cherukupalli, Rajeev

    2016-11-01

    To estimate the price elasticity of cigarette demand for university students aged 18-24 years in Jordan. Questions from the Global Adult Tobacco Survey were adapted and administered to students from 10 public universities in Jordan in 2014. A two-part econometric model of cigarette demand was estimated. Nearly one-third of university students in Jordan smoke, purchasing 33.2 packs per month and paying 1.70 Jordanian dinars on average (US$2.40) for a pack of 20 cigarettes. The price elasticity of cigarette demand was estimated to be -1.15. Higher taxes may be particularly effective in reducing smoking among University students in Jordan. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  1. Is the Demand for Alcoholic Beverages in Developing Countries Sensitive to Price? Evidence from China

    PubMed Central

    Tian, Guoqiang; Liu, Feng

    2011-01-01

    Economic literature in developed countries suggests that demand for alcoholic beverages is sensitive to price, with an estimated price elasticity ranging from −0.38 for beer and −0.7 for liquor. However, few studies have been conducted in developing countries. We employ a large individual-level dataset in China to estimate the effects of price on alcohol demand. Using the data from China Health and Nutrition Survey for the years 1993, 1997, 2000, 2004 and 2006, we estimate two-part models of alcohol demand. Results show the price elasticity is virtually zero for beer and only −0.12 for liquor, which is far smaller than those derived from developed countries. Separate regressions by gender reveals the results are mainly driven by men. The central implication of this study is, while alcohol tax increases can raise government revenue, it alone is not an effective policy to reduce alcohol related problems in China. PMID:21776220

  2. Price impact on urban residential water demand: A dynamic panel data approach

    NASA Astrophysics Data System (ADS)

    ArbuéS, Fernando; BarberáN, Ramón; Villanúa, Inmaculada

    2004-11-01

    In this paper, we formulate and estimate a model of residential water demand with the aim of evaluating the potential of pricing policies as a mechanism for managing residential water. The proposed econometric model offers a new perspective on urban water demand analysis by combining microlevel data with a dynamic panel data estimation procedure. The empirical application suggests that residential users are more responsive to a lagged average price specification. Another result of the estimated model is that price is a moderately effective tool in reducing residential water demand within the present range of prices, with the estimated values for income elasticity and "elasticity of consumption with respect to family size" reinforcing this conclusion.

  3. Validity of a Demand Curve Measure of Nicotine Reinforcement with Adolescent Smokers

    PubMed Central

    Murphy, James G.; MacKillop, James; Tidey, Jennifer W.; Brazil, Linda A.; Colby, Suzanne M.

    2010-01-01

    High or inelastic demand for drugs is central to many laboratory and theoretical models of drug abuse, but it has not been widely measured with human substance abusers. The authors used a simulated cigarette purchase task to generate a demand curve measure of nicotine reinforcement in a sample of 138 adolescent smokers. Participants reported the number of cigarettes they would purchase and smoke in a hypothetical day across a range of prices, and their responses were well-described by a regression equation that has been used to construct demand curves in drug self-administration studies. Several demand curve measures were generated, including breakpoint, intensity, elasticity, Pmax, and Omax. Although simulated cigarette smoking was price sensitive, smoking levels were high (8+ cigarettes/day) at prices up to 50¢ per cigarette, and the majority of the sample reported that they would purchase at least 1 cigarette at prices as high as $2.50 per cigarette. Higher scores on the demand indices Omax (maximum cigarette purchase expenditure), intensity (reported smoking level when cigarettes were free), and breakpoint (the first price to completely suppress consumption), and lower elasticity (sensitivity of cigarette consumption to increases in cost), were associated with greater levels of naturalistic smoking and nicotine dependence. Greater demand intensity was associated with lower motivation to change smoking. These results provide initial support for the validity of a self-report cigarette purchase task as a measure of economic demand for nicotine with adolescent smokers. PMID:20832200

  4. Speech measures indicating workload demand.

    PubMed

    Brenner, M; Doherty, E T; Shipp, T

    1994-01-01

    Heart rate and six speech measures were evaluated using a manual tracking task under different workload demands. Following training, 17 male subjects performed three task trials: a difficult trial, with a $50 incentive for successful performance at a very demanding level; an easy trial, with a $2 incentive for successful performance at a simple level; and a baseline trial, in which there was physiological monitoring but no tracking performance. Subjects counted aloud during the trials. It was found that heart rate, speaking fundamental frequency (pitch), and vocal intensity (loudness) increased significantly with workload demands. Speaking rate showed a marginal increase, while vocal jitter and vocal shimmer did not show reliable changes. A derived speech measure, which statistically combined information from all other speech measures except shimmer, was also evaluated. It increased significantly with workload demands and was surprisingly robust in showing differences for individual subjects. It appears that speech analysis can provide practical workload information.

  5. Industrial Demand Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Industrial Demand Module. The report catalogues and describes model assumptions, computational methodology, parameter estimation techniques, and model source code.

  6. Residential Demand Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Model Documentation - Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Residential Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, and FORTRAN source code.

  7. Saving Electricity and Demand Response

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Nobuyuki

    A lot of people lost their lives in the tremendous earthquake in Tohoku region on March 11. A large capacity of electric power plants in TEPCO area was also damaged and large scale power shortage in this summer is predicted. In this situation, electricity customers are making great effort to save electricity to avoid planned outage. Customers take actions not only by their selves but also by some customers' cooperative movements. All actions taken actually are based on responses to request form the government or voluntary decision. On the other hand, demand response based on a financial stimulus is not observed as an actual behavior. Saving electricity by this demand response only discussed in the newspapers. In this commentary, the events regarding electricity-saving measure after this disaster are described and the discussions on demand response, especially a raise in power rate, are put into shapes in the context of this electricity supply-demand gap.

  8. Industrial Demand Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Industrial Demand Module. The report catalogues and describes model assumptions, computational methodology, parameter estimation techniques, and model source code.

  9. Residential Demand Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Model Documentation - Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Residential Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, and FORTRAN source code.

  10. Elastic heterogeneity in metallic glasses.

    SciTech Connect

    Dmowski, , W.; Iwashita, T.; Chuang, C.-P.; Almer, J. D; Egami, T.; X-Ray Science Division; Univ. of Tennessee; ORNL

    2010-01-01

    When a stress is applied on a metallic glass it deforms following Hook's law. Therefore it may appear obvious that a metallic glass deforms elastically. Using x-ray diffraction and anisotropic pair-density function analysis we show that only about 3/4 in volume fraction of metallic glasses deforms elastically, whereas the rest of the volume is anelastic and in the experimental time scale deform without resistance. We suggest that this anelastic portion represents residual liquidity in the glassy state. Many theories, such as the free-volume theory, assume the density of defects in the glassy state to be of the order of 1%, but this result shows that it is as much as a quarter.

  11. Linear elastic fracture mechanics primer

    NASA Technical Reports Server (NTRS)

    Wilson, Christopher D.

    1992-01-01

    This primer is intended to remove the blackbox perception of fracture mechanics computer software by structural engineers. The fundamental concepts of linear elastic fracture mechanics are presented with emphasis on the practical application of fracture mechanics to real problems. Numerous rules of thumb are provided. Recommended texts for additional reading, and a discussion of the significance of fracture mechanics in structural design are given. Griffith's criterion for crack extension, Irwin's elastic stress field near the crack tip, and the influence of small-scale plasticity are discussed. Common stress intensities factor solutions and methods for determining them are included. Fracture toughness and subcritical crack growth are discussed. The application of fracture mechanics to damage tolerance and fracture control is discussed. Several example problems and a practice set of problems are given.

  12. Vibrations of elastically restrained frames

    NASA Astrophysics Data System (ADS)

    Albarracín, Carlos Marcelo; Grossi, Ricardo Oscar

    2005-07-01

    This paper deals with the determination of eigenfrequencies of a frame which consists of a beam supported by a column and is submitted to intermediate elastic constraints. The ends of the frame are elastically restrained against rotation and translation. The individual members of the frame are assumed to be governed by the transverse and axial vibration theory of an Euler-Bernoulli beam. The boundary and eigenvalue problem which governs the dynamical behavior of the frame structure is derived using the techniques of calculus of variations. Exact values of eigenfrequencies are determined by the application of the separation of variables method. Also, results are obtained by the use of the finite element method. The natural frequencies and mode shapes are presented for a wide range of values of the restraint parameters. Several particular cases are presented and some of these have been compared with those available in the literature.

  13. Elastic modulus of viral nanotubes

    NASA Astrophysics Data System (ADS)

    Zhao, Yue; Ge, Zhibin; Fang, Jiyu

    2008-09-01

    We report an experimental and theoretical study of the radial elasticity of tobacco mosaic virus (TMV) nanotubes. An atomic force microscope tip is used to apply small radial indentations to deform TMV nanotubes. The initial elastic response of TMV nanotubes can be described by finite-element analysis in 5nm indentation depths and Hertz theory in 1.5nm indentation depths. The derived radial Young’s modulus of TMV nanotubes is 0.92±0.15GPa from finite-element analysis and 1.0±0.2GPa from the Hertz model, which are comparable with the reported axial Young’s modulus of 1.1GPa [Falvo , Biophys. J. 72, 1396 (1997)].

  14. Elastic Heterogeneity in Metallic Glasses

    NASA Astrophysics Data System (ADS)

    Dmowski, W.; Iwashita, T.; Chuang, C.-P.; Almer, J.; Egami, T.

    2010-11-01

    When a stress is applied on a metallic glass it deforms following Hook’s law. Therefore it may appear obvious that a metallic glass deforms elastically. Using x-ray diffraction and anisotropic pair-density function analysis we show that only about (3)/(4) in volume fraction of metallic glasses deforms elastically, whereas the rest of the volume is anelastic and in the experimental time scale deform without resistance. We suggest that this anelastic portion represents residual liquidity in the glassy state. Many theories, such as the free-volume theory, assume the density of defects in the glassy state to be of the order of 1%, but this result shows that it is as much as a quarter.

  15. Elastic cone for Chinese calligraphy

    NASA Astrophysics Data System (ADS)

    Cai, Fenglei; Li, Haisheng

    2014-01-01

    The brush plays an important role in creating Chinese calligraphy. We regard a single bristle of a writing brush as an elastic rod and the brush tuft absorbing ink as an elastic cone, which naturally deforms according to the force exerted on it when painting on a paper, and the brush footprint is formed by the intersection region between the deformed tuft and the paper plane. To efficiently generate brush strokes, this paper introduces interpolation and texture mapping approach between two adjacent footprints, and automatically applies bristle-splitting texture to the stroke after long-time painting. Experimental results demonstrate that our method is effective and reliable. Users can create realistic calligraphy in real time.

  16. Structure and elasticity of glaucophane

    NASA Astrophysics Data System (ADS)

    Bezacier, L.; Mookherjee, M.

    2012-12-01

    We report equation of state and elasticity of glaucophane amphibole [Na2Mg3Al2Si8O22(OH)2] up to 9 GPa, which encompasses its experimentally observed stability field. The full elastic constant tensor reveals significantly larger stiffness along (100) plane. The [100] direction is relatively softer. This anisotropy is related to the stacking of the stiffer tetrahedral units along [010] and [001] directions within the crystal structure. Glaucophane is a dominant mineral constituent of blueschist facies rock, and has significantly lower velocities compared to garnet bearing eclogites. In addition, glaucophane is anisotropic and could account for the observed low velocity layer (LVL) in the subducting slabs at depth range within the thermodynamic stability of glaucophane.

  17. Elastic sealants for surgical applications.

    PubMed

    Annabi, Nasim; Yue, Kan; Tamayol, Ali; Khademhosseini, Ali

    2015-09-01

    Sealants have emerged as promising candidates for replacing sutures and staples to prevent air and liquid leakages during and after the surgeries. Their physical properties and adhesion strength to seal the wound area without limiting the tissue movement and function are key factors in their successful implementation in clinical practice. In this contribution, the advances in the development of elastic sealants formed from synthetic and natural materials are critically reviewed and their shortcomings are pointed out. In addition, we highlight the applications in which elasticity of the sealant is critical and outline the limitations of the currently available sealants. This review will provide insights for the development of novel bioadhesives with advanced functionality for surgical applications.

  18. Computational Imaging in Demanding Conditions

    DTIC Science & Technology

    2015-11-18

    AFRL-AFOSR-VA-TR-2015-0380 Computational Imaging in Demanding Conditions Peyman Milanfar UNIVERSITY OF CALIFORNIA SANTA CRUZ Final Report 11/18/2015...Computational Imaging in Demanding Conditions 5a. CONTRACT NUMBER FA9550-11-1-0227 5b. GRANT NUMBER FA9550-11-1-0227 5c. PROGRAM ELEMENT NUMBER... WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 8

  19. Demand Response Spinning Reserve Demonstration

    SciTech Connect

    Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.

    2007-05-01

    The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

  20. Demand, Energy, and Power Factor

    DTIC Science & Technology

    1994-08-01

    plants provide to the IAC, and in particular, the effects of demand, block extenders, and power factor on plant utility costs and energy conservation...costs. Education of plant personnel about these effects is also described. Another purpose of this report is to provide a listing of types of typical...the lAC, and in particular, the effects of demand, block extenders, and power factor on plant utility costs and energy conservation costs. 5 Education

  1. A Behavioral Economic Approach to Assessing Demand for Marijuana

    PubMed Central

    Collins, R. Lorraine; Vincent, Paula C.; Yu, Jihnhee; Liu, Liu; Epstein, Leonard H.

    2014-01-01

    In the U.S., marijuana is the most commonly used illicit drug. Its prevalence is growing, particularly among young adults. Behavioral economic indices of the relative reinforcing efficacy (RRE) of substances have been used to examine the appeal of licit (e.g., alcohol) and illicit (e.g., heroin) drugs. The present study is the first to use an experimental, simulated purchasing task to examine the RRE of marijuana. Young-adult (M age = 21.64 years) recreational marijuana users (N = 59) completed a computerized marijuana purchasing task designed to generate demand curves and the related RRE indices (e.g., intensity of demand - purchases at lowest price; Omax - max. spent on marijuana; Pmax - price at which marijuana expenditure is max). Participants “purchased” high-grade marijuana across 16 escalating prices that ranged from $0/free to $160/joint. They also provided 2-weeks of real-time, ecological momentary assessment reports on their marijuana use. The purchasing task generated multiple RRE indices. Consistent with research on other substances, the demand for marijuana was inelastic at lower prices but became elastic at higher prices, suggesting that increases in the price of marijuana could lessen its use. In regression analyses, the intensity of demand, Omax and Pmax, and elasticity each accounted for significant variance in real-time marijuana use. These results provide support for the validity of a simulated marijuana purchasing task to examine its reinforcing efficacy. This study highlights the value of applying a behavioral economic framework to young-adult marijuana use and has implications for prevention, treatment, and policies to regulate marijuana use. PMID:24467370

  2. Stability of elastically supported columns

    NASA Technical Reports Server (NTRS)

    Niles, Alfred S; Viscovich, Steven J

    1942-01-01

    A criterion is developed for the stiffness required of elastic lateral supports at the ends of a compression member to provide stability. A method based on this criterion is then developed for checking the stability of a continuous beam-column. A related method is also developed for checking the stability of a member of a pin-jointed truss against rotation in the plane of the truss.

  3. Elastic Curves on the Sphere

    DTIC Science & Technology

    1992-12-16

    12 = (K,, + )- (29) K 2 (see [3]). The parameter KM represents the amplitude of the periodic curva - ture function and sm denotes the value at which K...Additamentum De curvis elasticis. Methodus Inveniendi Lineas Curvas Maximi Minimive Proprietate Gaudentes, Ser. 1., Vol. 24, Lausanne 1744. 17 [10...Mathematical Theory of Elasticity. 4th. ed., Cambridge University Press, 1927. [12] G. Nielson. Bernstein/ Bezier Curves and Splines on Spheres based upon

  4. Improved Indentation Test for Measuring Nonlinear Elasticity

    NASA Technical Reports Server (NTRS)

    Eldridge, Jeffrey I.

    2004-01-01

    A cylindrical-punch indentation technique has been developed as a means of measuring the nonlinear elastic responses of materials -- more specifically, for measuring the moduli of elasticity of materials in cases in which these moduli vary with applied loads. This technique offers no advantage for characterizing materials that exhibit purely linear elastic responses (constant moduli of elasticity, independent of applied loads). However, the technique offers a significant advantage for characterizing such important materials as plasma-sprayed thermal-barrier coatings, which, in cyclic loading, exhibit nonlinear elasticity with hysteresis related to compaction and sliding within their microstructures.

  5. Teaching nonlinear dynamics through elastic cords

    NASA Astrophysics Data System (ADS)

    Chacón, R.; Galán, C. A.; Sánchez-Bajo, F.

    2011-01-01

    We experimentally studied the restoring force of a length of stretched elastic cord. A simple analytical expression for the restoring force was found to fit all the experimental results for different elastic materials. Remarkably, this analytical expression depends upon an elastic-cord characteristic parameter which exhibits two limiting values corresponding to two nonlinear springs with different Hooke's elastic constants. Additionally, the simplest model of elastic cord dynamics is capable of exhibiting a great diversity of nonlinear phenomena, including bifurcations and chaos, thus providing a suitable alternative model system for discussing the basic essentials of nonlinear dynamics in the context of intermediate physics courses at university level.

  6. Normal stresses in elastic networks

    NASA Astrophysics Data System (ADS)

    Cioroianu, Adrian R.; Storm, Cornelis

    2013-11-01

    When loaded in simple shear deformation, polymeric materials may develop so-called normal stresses: stresses perpendicular to the direction of the applied shear. These normal stresses are intrinsically nonlinear: basic symmetry considerations dictate they may only enter at O(γ2), with γ the dimensionless shear strain. There is no fundamental restriction on their sign, and normal stresses may be positive (pushing outward) or negative (pulling inward). Most materials tend to dilate in the normal direction, but a wide variety of biopolymer networks including fibrin and actin gels have been reported to present anomalously large, negative normal stresses—a feature which has been ascribed to the intrinsic elastic nonlinearity of semiflexible fibers. In this work, we present analytical results on a model nonlinear network, which we expand to the required nonlinear order to show that due to geometric, rather than elastic, nonlinearities (negative) normal stresses generically arise in filamentous networks—even in networks composed of linear, Hookean springs. We investigate analytically and numerically how the subsequent addition of elastic nonlinearities, nonaffine deformations, and filament persistence through cross-linkers augment this basic behavior.

  7. Phase diagram of elastic spheres.

    PubMed

    Athanasopoulou, L; Ziherl, P

    2017-02-15

    Experiments show that polymeric nanoparticles often self-assemble into several non-close-packed lattices in addition to the face-centered cubic lattice. Here, we explore theoretically the possibility that the observed phase sequences may be associated with the softness of the particles, which are modeled as elastic spheres interacting upon contact. The spheres are described by two finite-deformation theories of elasticity, the modified Saint-Venant-Kirchhoff model and the neo-Hookean model. We determine the range of indentations where the repulsion between the spheres is pairwise additive and agrees with the Hertz theory. By computing the elastic energies of nine trial crystal lattices at densities far beyond the Hertzian range, we construct the phase diagram and find the face- and body-centered cubic lattices as well as the A15 lattice and the simple hexagonal lattice, with the last two being stable at large densities where the spheres are completely faceted. These results are qualitatively consistent with observations, suggesting that deformability may indeed be viewed as a generic property that determines the phase behavior in nanocolloidal suspensions.

  8. Elastic proteins: biological roles and mechanical properties.

    PubMed Central

    Gosline, John; Lillie, Margo; Carrington, Emily; Guerette, Paul; Ortlepp, Christine; Savage, Ken

    2002-01-01

    The term 'elastic protein' applies to many structural proteins with diverse functions and mechanical properties so there is room for confusion about its meaning. Elastic implies the property of elasticity, or the ability to deform reversibly without loss of energy; so elastic proteins should have high resilience. Another meaning for elastic is 'stretchy', or the ability to be deformed to large strains with little force. Thus, elastic proteins should have low stiffness. The combination of high resilience, large strains and low stiffness is characteristic of rubber-like proteins (e.g. resilin and elastin) that function in the storage of elastic-strain energy. Other elastic proteins play very different roles and have very different properties. Collagen fibres provide exceptional energy storage capacity but are not very stretchy. Mussel byssus threads and spider dragline silks are also elastic proteins because, in spite of their considerable strength and stiffness, they are remarkably stretchy. The combination of strength and extensibility, together with low resilience, gives these materials an impressive resistance to fracture (i.e. toughness), a property that allows mussels to survive crashing waves and spiders to build exquisite aerial filters. Given this range of properties and functions, it is probable that elastic proteins will provide a wealth of chemical structures and elastic mechanisms that can be exploited in novel structural materials through biotechnology. PMID:11911769

  9. Elastic fingering patterns in confined lifting flows.

    PubMed

    Fontana, João V; Miranda, José A

    2016-09-01

    The elastic fingering phenomenon occurs when two confined fluids are brought into contact, and due to a chemical reaction, the interface separating them becomes elastic. We study elastic fingering pattern formation in Newtonian fluids flowing in a lifting (time-dependent gap) Hele-Shaw cell. Using a mode-coupling approach, nonlinear effects induced by the interplay between viscous and elastic forces are investigated and the weakly nonlinear behavior of the fluid-fluid interfacial patterns is analyzed. Our results indicate that the existence of the elastic interface allows the development of unexpected morphological behaviors in such Newtonian fluid flow systems. More specifically, we show that depending on the values of the governing physical parameters, the observed elastic fingering structures are characterized by the occurrence of either finger tip splitting or side branching. The impact of the elastic interface on finger-competition events is also discussed.

  10. Household demand for insecticide-treated bednets in Tanzania and policy options for increasing uptake.

    PubMed

    Gingrich, Chris D; Hanson, Kara G; Marchant, Tanya J; Mulligan, Jo-Ann; Mponda, Hadji

    2011-03-01

    There has been considerable controversy about the most appropriate means of delivering insecticide-treated nets (ITNs) to prevent malaria. Household demand for ITNs is a key factor influencing the choice of delivery strategy, but evidence to date about price and income elasticities comes either from studies of hypothetical willingness to pay or small-scale policy experiments. This study estimates the price and income elasticities of demand for ITNs using nationally representative household survey data and actual consumer choices, in the context of a national scheme to provide vouchers for subsidized nets to pregnant women in Tanzania. Under this distribution system, the estimated price elasticity of demand for subsidized ITNs equals -0.12 and the income elasticity estimates range from zero to 0.47, depending on household socio-economic status. The model also shows a substantial decline in short-term ITN purchases for women whose household received a free ITN. These findings suggest that if the Tanzanian government continues to use a mixed public-private model to distribute ITNs, increasing the consumer subsidy alone will not dramatically improve ITN coverage. A concerted effort is required including an increase in the subsidy amount, attention to income growth for poor households, increases in women's and girls' education levels, and expansion of the retail ITN distribution network. Use of a catch-up campaign to distribute free ITNs would increase coverage but raises questions about the effect of households' long-term purchase decisions for ITNs.

  11. Effects of price and availability on abortion demand.

    PubMed

    Gohmann, S F; Ohsfeldt, R L

    1993-10-01

    This study explained the variation in US state abortion demand due to the price of services, the net of insurance cost of birth services, the ability to pay, contraceptive use, individual attitudes regarding abortion, and government policy affecting cost of benefits of terminating an unintended pregnancy or of carrying to birth. The empirical model uses pooled data from 48 states for 1982, 1984, 1985, and 1987. Prices are deflated to 1977 dollars. Another two-staged least squares model is based on cross-sectional state level data for 1985. The dependent variable is the log of abortion per 1000 pregnancies. Other variables pertain to income, education, labor force, family planning, tax, aid to families with dependent children, religion, and abortion-related measures. The results of the cross-sectional analysis are consistent with Medoff's and Garbacz's findings. The estimated coefficient of per capita income is positive with a point elasticity ranging from 0.62 to 1.0. The model with the most complete specifications has an abortion price elasticity range from -0.75 to -1.3 and is statistically significant when religion measures are excluded. The Hausman test shows the pro-choice variable significantly correlated with the error term. The net price of birth services is not statistically significant. Catholic religion and no religion are only significant when the abortion provider variable is excluded. The suggestion is that the effect of Catholicism is ambiguous. In the pooled analysis, the fixed effects model is used to control for abortion attitudes and other unobserved factors. Abortion demand includes abortion per 1000 pregnancies, the ratio of abortions to pregnancies, and the logarithm of abortions per 1000 pregnancies. Higher income is associated with a higher abortion rate and elasticities of 0.76 and 0.35 and is associated with a higher pregnancy rate. The abortion ratio is found to be elastic with respect to price, and price elasticities are sensitive to

  12. Insatiable demands: Income, energy and environmental policy in Madagascar

    SciTech Connect

    Shaw, C.L.

    1993-01-01

    The island nation of Madagascar is suffering the collision of three distinct trends: economic stagnation, a rapidly expanding population and a severely threatened natural resource base. Demands for growth, new energy reserves and environmental conservation, especially of forest resources, are creating a policy dilemma for both government officials and donors. This study seeks to bring new evidence to bear on this policy dilemma. Primary data on urban household income, family size and consumption of various energy types are used to test two main hypothesis (1) that charcoal, which constitutes the fuel of choice for a vast majority of the sample, is a normal rather than an inferior good, and (2) that demand for wood-fuels constitutes a genuine threat to the viability of the forest resource. The data indicate that income elasticities of demand for charcoal are positive over a broad range of per capita income levels, revealing that charcoal is, indeed a normal good for a large portion of the population represented by the sample. A model of forest degradation is built which establishes a clear link between wood-fuel demand and forest degradation. Together, these findings make clear that under current income patterns, and for the forseeable future, charcoal is a normal good and its consumption by urban residents constitutes a serious threat to the natural forest resource. The study concludes with a policy analysis which identifies existing market failures due to government policies and recommends changes based on tested policy prescriptions in other parts of the developing world.

  13. Oil Price Uncertainty, Transport Fuel Demand and Public Health

    PubMed Central

    He, Ling-Yun; Yang, Sheng; Chang, Dongfeng

    2017-01-01

    Based on the panel data of 306 cities in China from 2002 to 2012, this paper investigates China’s road transport fuel (i.e., gasoline and diesel) demand system by using the Almost Ideal Demand System (AIDS) and the Quadratic AIDS (QUAIDS) models. The results indicate that own-price elasticities for different vehicle categories range from −1.215 to −0.459 (by AIDS) and from −1.399 to −0.369 (by QUAIDS). Then, this study estimates the air pollution emissions (CO, NOx and PM2.5) and public health damages from the road transport sector under different oil price shocks. Compared to the base year 2012, results show that a fuel price rise of 30% can avoid 1,147,270 tonnes of pollution emissions; besides, premature deaths and economic losses decrease by 16,149 cases and 13,817.953 million RMB yuan respectively; while based on the non-linear health effect model, the premature deaths and total economic losses decrease by 15,534 and 13,291.4 million RMB yuan respectively. Our study combines the fuel demand and health evaluation models and is the first attempt to address how oil price changes influence public health through the fuel demand system in China. Given its serious air pollution emission and substantial health damages, this paper provides important insights for policy makers in terms of persistent increasing in fuel consumption and the associated health and economic losses. PMID:28257076

  14. Probabilistic seismic demand analysis using advanced ground motion intensity measures

    USGS Publications Warehouse

    Tothong, P.; Luco, N.

    2007-01-01

    One of the objectives in performance-based earthquake engineering is to quantify the seismic reliability of a structure at a site. For that purpose, probabilistic seismic demand analysis (PSDA) is used as a tool to estimate the mean annual frequency of exceeding a specified value of a structural demand parameter (e.g. interstorey drift). This paper compares and contrasts the use, in PSDA, of certain advanced scalar versus vector and conventional scalar ground motion intensity measures (IMs). One of the benefits of using a well-chosen IM is that more accurate evaluations of seismic performance are achieved without the need to perform detailed ground motion record selection for the nonlinear dynamic structural analyses involved in PSDA (e.g. record selection with respect to seismic parameters such as earthquake magnitude, source-to-site distance, and ground motion epsilon). For structural demands that are dominated by a first mode of vibration, using inelastic spectral displacement (Sdi) can be advantageous relative to the conventionally used elastic spectral acceleration (Sa) and the vector IM consisting of Sa and epsilon (??). This paper demonstrates that this is true for ordinary and for near-source pulse-like earthquake records. The latter ground motions cannot be adequately characterized by either Sa alone or the vector of Sa and ??. For structural demands with significant higher-mode contributions (under either of the two types of ground motions), even Sdi (alone) is not sufficient, so an advanced scalar IM that additionally incorporates higher modes is used.

  15. Chicago's water market: Dynamics of demand, prices and scarcity rents

    USGS Publications Warehouse

    Ipe, V.C.; Bhagwat, S.B.

    2002-01-01

    Chicago and its suburbs are experiencing an increasing demand for water from a growing population and economy and may experience water scarcity in the near future. The Chicago metropolitan area has nearly depleted its groundwater resources to a point where interstate conflicts with Wisconsin could accompany an increased reliance on those sources. Further, the withdrawals from Lake Michigan is limited by the Supreme Court decree. The growing demand and indications of possible scarcity suggest a need to reexamine the pricing policies and the dynamics of demand. The study analyses the demand for water and develops estimates of scarcity rents for water in Chicago. The price and income elasticities computed at the means are -0.002 and 0.0002 respectively. The estimated scarcity rents ranges from $0.98 to $1.17 per thousand gallons. The results indicate that the current prices do not fully account for the scarcity rents and suggest a current rate with in the range $1.53 to $1.72 per thousand gallons.

  16. Effects of Experimental Income on Demand for Potentially Real Cigarettes

    PubMed Central

    Wilson, Arlington George; Bickel, Warren K.

    2015-01-01

    Introduction: Cigarette demand, or the change in cigarette consumption as a function of price, is a measure of reinforcement that is associated with level of tobacco dependence and other clinically relevant measures, but the effects of experimentally controlled income on real-world cigarette consumption have not been examined. Methods: In this study, income available for cigarette purchases was manipulated to assess the effect on cigarette demand. Tobacco-dependent cigarette smokers (n = 15) who smoked 10–40 cigarettes per day completed a series of cigarette purchasing tasks under a variety of income conditions meant to mimic different weekly cigarette budgets: $280, approximately $127, $70, or approximately $32 per week. Prices of $0.12, $0.25, $0.50, and $1.00 per cigarette were assessed in each income condition. Participants were instructed to purchase as many cigarettes as they would like for the next week and to only consume cigarettes purchased in the context of the study. One price in 1 income condition was randomly chosen to be “real,” and the cigarettes and the excess money in the budget for that condition were given to the participant. Results: Results indicate that demand elasticity was negatively correlated with income. Demand intensity (consumption at low prices) was unrelated to income condition and remained high across incomes. Conclusions: These results indicate that the amount of income that is available for cigarette purchases has a large effect on cigarette consumption, but only at high prices. PMID:25168032

  17. Adaptive Quality of Transmission Control in Elastic Optical Network

    NASA Astrophysics Data System (ADS)

    Cai, Xinran

    Optical fiber communication is becoming increasingly important due to the burgeoning demand in the internet capacity. However, traditional wavelength division multiplexing (WDM) technique fails to address such demand because of its inefficient spectral utilization. As a result, elastic optical networking (EON) has been under extensive investigation recently. Such network allows sub-wavelength and super-wavelength channel accommodation, and mitigates the stranded bandwidth problem in the WDM network. In addition, elastic optical network is also able to dynamically allocate the spectral resources of the network based on channel conditions and impairments, and adaptively control the quality of transmission of a channel. This application requires two aspects to be investigated: an efficient optical performance monitoring scheme and networking control and management algorithms to reconfigure the network in a dynamic fashion. This thesis focuses on the two aspects discussed above about adaptive QoT control. We demonstrated a supervisory channel method for optical signal to noise ratio (OSNR) and chromatic dispersion (CD) monitoring. In addition, our proof-of-principle testbed experiments show successful impairment aware reconfiguration of the network with modulation format switching (MFS) only and MFS combined with lightpath rerouting (LR) for hundred-GHz QPSK superchannels undergoing time-varying OSNR impairment.

  18. Identifying Demand Responses to Illegal Drug Supply Interdictions.

    PubMed

    Cunningham, Scott; Finlay, Keith

    2016-10-01

    Successful supply-side interdictions into illegal drug markets are predicated on the responsiveness of drug prices to enforcement and the price elasticity of demand for addictive drugs. We present causal estimates that targeted interventions aimed at methamphetamine input markets ('precursor control') can temporarily increase retail street prices, but methamphetamine consumption is weakly responsive to higher drug prices. After the supply interventions, purity-adjusted prices increased then quickly returned to pre-treatment levels within 6-12 months, demonstrating the short-term effects of precursor control. The price elasticity of methamphetamine demand is -0.13 to -0.21 for self-admitted drug treatment admissions and between -0.24 and -0.28 for hospital inpatient admissions. We find some evidence of a positive cross-price effect for cocaine, but we do not find robust evidence that increases in methamphetamine prices increased heroin, alcohol, or marijuana drug use. This study can inform policy discussions regarding other synthesized drugs, including illicit use of pharmaceuticals. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Respiratory-related limitations in physically demanding occupations.

    PubMed

    Brown, Peter I; McConnell, Alison K

    2012-04-01

    Respiratory muscle work limits high-intensity exercise tolerance in healthy human beings. Emerging evidence suggests similar limitations exist during submaximal work in some physically demanding occupations. In an occupational setting, heavy loads are routinely carried upon the trunk in the form of body armor, backpacks, and/or compressed air cylinders by military, emergency service, and mountain rescue personnel. This personal and respiratory protective equipment impairs respiratory muscle function and increases respiratory muscle work. More specifically, thoracic load carriage induces a restrictive ventilatory limitation which increases the elastic work of breathing, rendering the respiratory muscles vulnerable to fatigue and inducing a concomitant reduction in exercise tolerance. Similarly, breathing apparatus worn by occupational personnel, including fire fighters and military and commercial divers, increases the inspiratory elastic and expiratory resistive work of breathing, precipitating significant inspiratory and expiratory muscle fatigue and a reduction in exercise tolerance. An argument is presented that the unique respiratory challenges encountered in some occupational settings require further research, since these may affect the operational effectiveness and the health and safety of personnel working in physically demanding occupations.

  20. Energy supply and demand in California

    NASA Technical Reports Server (NTRS)

    Griffith, E. D.

    1978-01-01

    The author expresses his views on future energy demand on the west coast of the United States and how that energy demand translates into demand for major fuels. He identifies the major uncertainties in determining what future demands may be. The major supply options that are available to meet projected demands and the policy implications that flow from these options are discussed.

  1. Price Elasticities for Energy Use in Buildings of the United States

    EIA Publications

    2014-01-01

    Energy demand tends to be responsive to changes in energy prices, a concept in economics known as price elasticity. Generally, an increase in a fuel price causes users to use less of that fuel or switch to a different fuel. The extent to which each of these changes takes place is of high importance to stakeholders in the energy sector and especially in energy planning. The purpose of this analysis is to determine fuel-price elasticities in stationary structures, particularly in the residential and commercial sectors.

  2. The Demand for Cigarettes as Derived from the Demand for Weight Loss: A Theoretical and Empirical Investigation.

    PubMed

    Cawley, John; Dragone, Davide; Von Hinke Kessler Scholder, Stephanie

    2016-01-01

    This paper offers an economic model of smoking and body weight and provides new empirical evidence on the extent to which the demand for cigarettes is derived from the demand for weight loss. In the model, smoking causes weight loss in addition to having direct utility benefits and direct health consequences. It predicts that some individuals smoke for weight loss and that the practice is more common among those who consider themselves overweight and those who experience greater disutility from excess weight. We test these hypotheses using nationally representative data in which adolescents are directly asked whether they smoke to control their weight. We find that, among teenagers who smoke frequently, 46% of girls and 30% of boys are smoking in part to control their weight. As predicted by the model, this practice is significantly more common among those who describe themselves as too fat and among groups that tend to experience greater disutility from obesity. We conclude by discussing the implications of these findings for tax policy; specifically, the demand for cigarettes is less price elastic among those who smoke for weight loss, all else being equal. Public health efforts to reduce smoking initiation and encourage cessation may wish to design campaigns to alter the derived nature of cigarette demand, especially among adolescent girls. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Fundamental Travel Demand Model Example

    NASA Technical Reports Server (NTRS)

    Hanssen, Joel

    2010-01-01

    Instances of transportation models are abundant and detailed "how to" instruction is available in the form of transportation software help documentation. The purpose of this paper is to look at the fundamental inputs required to build a transportation model by developing an example passenger travel demand model. The example model reduces the scale to a manageable size for the purpose of illustrating the data collection and analysis required before the first step of the model begins. This aspect of the model development would not reasonably be discussed in software help documentation (it is assumed the model developer comes prepared). Recommendations are derived from the example passenger travel demand model to suggest future work regarding the data collection and analysis required for a freight travel demand model.

  4. International Oil Supplies and Demands

    SciTech Connect

    Not Available

    1991-09-01

    The eleventh Energy Modeling Forum (EMF) working group met four times over the 1989--90 period to compare alternative perspectives on international oil supplies and demands through 2010 and to discuss how alternative supply and demand trends influence the world's dependence upon Middle Eastern oil. Proprietors of eleven economic models of the world oil market used their respective models to simulate a dozen scenarios using standardized assumptions. From its inception, the study was not designed to focus on the short-run impacts of disruptions on oil markets. Nor did the working group attempt to provide a forecast or just a single view of the likely future path for oil prices. The model results guided the group's thinking about many important longer-run market relationships and helped to identify differences of opinion about future oil supplies, demands, and dependence.

  5. International Oil Supplies and Demands

    SciTech Connect

    Not Available

    1992-04-01

    The eleventh Energy Modeling Forum (EMF) working group met four times over the 1989--1990 period to compare alternative perspectives on international oil supplies and demands through 2010 and to discuss how alternative supply and demand trends influence the world's dependence upon Middle Eastern oil. Proprietors of eleven economic models of the world oil market used their respective models to simulate a dozen scenarios using standardized assumptions. From its inception, the study was not designed to focus on the short-run impacts of disruptions on oil markets. Nor did the working group attempt to provide a forecast or just a single view of the likely future path for oil prices. The model results guided the group's thinking about many important longer-run market relationships and helped to identify differences of opinion about future oil supplies, demands, and dependence.

  6. Turkey's energy demand and supply

    SciTech Connect

    Balat, M.

    2009-07-01

    The aim of the present article is to investigate Turkey's energy demand and the contribution of domestic energy sources to energy consumption. Turkey, the 17th largest economy in the world, is an emerging country with a buoyant economy challenged by a growing demand for energy. Turkey's energy consumption has grown and will continue to grow along with its economy. Turkey's energy consumption is high, but its domestic primary energy sources are oil and natural gas reserves and their production is low. Total primary energy production met about 27% of the total primary energy demand in 2005. Oil has the biggest share in total primary energy consumption. Lignite has the biggest share in Turkey's primary energy production at 45%. Domestic production should be to be nearly doubled by 2010, mainly in coal (lignite), which, at present, accounts for almost half of the total energy production. The hydropower should also increase two-fold over the same period.

  7. Price elasticity of tobacco products among economic classes in India, 2011–2012

    PubMed Central

    Selvaraj, Sakthivel; Srivastava, Swati; Karan, Anup

    2015-01-01

    Objectives The objectives of this study are to: (1) examine the pattern of price elasticity of three major tobacco products (bidi, cigarette and leaf tobacco) by economic groups of population based on household monthly per capita consumption expenditure in India and (2) assess the effect of tax increases on tobacco consumption and revenue across expenditure groups. Setting Data from the 2011–2012 nationally representative Consumer Expenditure Survey from 101 662 Indian households were used. Participants Households which consumed any tobacco or alcohol product were retained in final models. Primary outcome measures The study draws theoretical frameworks from a model using the augmented utility function of consumer behaviour, with a two-stage two-equation system of unit values and budget shares. Primary outcome measures were price elasticity of demand for different tobacco products for three hierarchical economic groups of population and change in tax revenue due to changes in tax structure. We finally estimated price elasticity of demand for bidi, cigarette and leaf tobacco and effects of changes in their tax rates on demand for these tobacco products and tax revenue. Results Own price elasticities for bidi were highest in the poorest group (−0.4328) and lowest in the richest group (−0.0815). Cigarette own price elasticities were −0.832 in the poorest group and −0.2645 in the richest group. Leaf tobacco elasticities were highest in the poorest (−0.557) and middle (−0.4537) groups. Conclusions Poorer group elasticities were the highest, indicating that poorer consumers are more price responsive. Elasticity estimates show positive distributional effects of uniform bidi and cigarette taxation on the poorest consumers, as their consumption is affected the most due to increases in taxation. Leaf tobacco also displayed moderate elasticities in poor and middle tertiles, suggesting that tax increases may result in a trade-off between consumption decline and

  8. Price elasticity of tobacco products among economic classes in India, 2011-2012.

    PubMed

    Selvaraj, Sakthivel; Srivastava, Swati; Karan, Anup

    2015-12-09

    The objectives of this study are to: (1) examine the pattern of price elasticity of three major tobacco products (bidi, cigarette and leaf tobacco) by economic groups of population based on household monthly per capita consumption expenditure in India and (2) assess the effect of tax increases on tobacco consumption and revenue across expenditure groups. Data from the 2011-2012 nationally representative Consumer Expenditure Survey from 101,662 Indian households were used. Households which consumed any tobacco or alcohol product were retained in final models. The study draws theoretical frameworks from a model using the augmented utility function of consumer behaviour, with a two-stage two-equation system of unit values and budget shares. Primary outcome measures were price elasticity of demand for different tobacco products for three hierarchical economic groups of population and change in tax revenue due to changes in tax structure. We finally estimated price elasticity of demand for bidi, cigarette and leaf tobacco and effects of changes in their tax rates on demand for these tobacco products and tax revenue. Own price elasticities for bidi were highest in the poorest group (-0.4328) and lowest in the richest group (-0.0815). Cigarette own price elasticities were -0.832 in the poorest group and -0.2645 in the richest group. Leaf tobacco elasticities were highest in the poorest (-0.557) and middle (-0.4537) groups. Poorer group elasticities were the highest, indicating that poorer consumers are more price responsive. Elasticity estimates show positive distributional effects of uniform bidi and cigarette taxation on the poorest consumers, as their consumption is affected the most due to increases in taxation. Leaf tobacco also displayed moderate elasticities in poor and middle tertiles, suggesting that tax increases may result in a trade-off between consumption decline and revenue generation. A broad spectrum rise in tax rates across all products is critical for

  9. Euler-Lagrange Elasticity: elasticity without stress or strain

    NASA Astrophysics Data System (ADS)

    Hardy, Humphrey

    2014-03-01

    A Euler-Lagrange (E-L) approach to elasticity is proposed that produces differential equations of elasticity without the need to define stress or strain tensors. The positions of the points within the body are the independent parameters instead of strain. Force replaces stress. The advantage of this approach is that the E-L differential equations are the same for both infinitesimal and finite deformations. Material properties are expressed in terms of the energy of deformation. The energy is expressed as a function of the principal invariants of the deformation gradient tensor. This scalar invariant representation of the energy of deformation enters directly into the E-L differential equations so that there is no need to define fourth order tensor material properties. By experimentally measuring the force and displacement of materials the functional form of the energy of deformation can be determined. The E-L differential equations can be input directly into finite element, finite difference, or other numerical models. If desired, stress and stain can be calculated as dependent parameters.

  10. Variable Joint Elasticities in Running

    NASA Astrophysics Data System (ADS)

    Peter, Stephan; Grimmer, Sten; Lipfert, Susanne W.; Seyfarth, Andre

    In this paper we investigate how spring-like leg behavior in human running is represented at joint level. We assume linear torsion springs in the joints and between the knee and the ankle joint. Using experimental data of the leg dynamics we compute how the spring parameters (stiffness and rest angles) change during gait cycle. We found that during contact the joints reveal elasticity with strongly changing parameters and compare the changes of different parameters for different spring arrangements. The results may help to design and improve biologically inspired spring mechanisms with adjustable parameters.

  11. Elasticity of Poissonian fiber networks

    NASA Astrophysics Data System (ADS)

    Åström, J. A.; Mäkinen, J. P.; Alava, M. J.; Timonen, J.

    2000-05-01

    An effective-medium model is introduced for the elasticity of two-dimensional random fiber networks. These networks are commonly used as basic models of heterogeneous fibrous structures such as paper. Using the exact Poissonian statistics to describe the microscopic geometry of the network, the tensile modulus can be expressed by a single-parameter function. This parameter depends on the network density and fiber dimensions, which relate the macroscopic modulus to the relative importance of axial and bending deformations of the fibers. The model agrees well with simulation results and experimental findings. We also discuss the possible generalizations of the model.

  12. [Fiscal policy, affordability and cross effects in the demand for tobacco products: the case of Uruguay].

    PubMed

    Carbajales, Alejandro Ramos; Curti, Dardo

    2010-01-01

    Uruguay, a country with a solid tobacco control policy since 2005 shows, contrary to expectations, an insignificant decrease in total tobacco products' sales in the last five years. The hypothesis is that on one side, changes in household income and the income elasticity of the demand for cigarettes were important countervailing factors in the demand of both products. The period 2005-2009 shows a large increase of 36% in household real income in Uruguay due to fast economic recovery after the 2002 crisis. The second factor is the interchangeability of roll your own and cigarettes and the impact on the demand of each product as a reaction to tax and price changes. The tax and price of roll your own tobacco remains substantially lower than that of cigarettes. This fact, and the increased substitution of roll your own for cigarettes seems to be the main reasons for the low impact of the policy of tobacco tax and price increases. This paper then consists of a revision of a 2004 study to estimate separate demands for both main tobacco products and obtain estimates for own price, cross price and income elasticities. Then, a simulation study was performed using the elasticities found and two scenarios of increases in household income: moderate (2.5% per year) and high (5% per year) confirming that countries where income is growing fast and with a potential for substitution towards cheaper products require substantial cigarette tax and price increases for a fiscal tobacco control policy to become effective.

  13. Area Under the Curve as a Novel Metric of Behavioral Economic Demand for Alcohol

    PubMed Central

    Amlung, Michael; Yurasek, Ali; McCarty, Kayleigh N.; MacKillop, James; Murphy, James G.

    2015-01-01

    Behavioral economic purchase tasks can be readily used to assess demand for a number of addictive substances including alcohol, tobacco and illicit drugs. However, several methodological limitations associated with the techniques used to quantify demand may reduce the utility of demand measures. In the present study, we sought to introduce area under the curve (AUC), commonly used to quantify degree of delay discounting, as a novel index of demand. A sample of 207 heavy drinking college students completed a standard alcohol purchase task and provided information about typical weekly drinking patterns and alcohol-related problems. Level of alcohol demand was quantified using AUC – which reflects the entire amount of consumption across all drink prices - as well as the standard demand indices (e.g., intensity, breakpoint, Omax, Pmax, and elasticity). Results indicated that AUC was significantly correlated with each of the other demand indices (rs = .42–.92), with particularly strong associations with Omax (r = .92). In regression models, AUC and intensity were significant predictors of weekly drinking quantity and AUC uniquely predicted alcohol-related problems, even after controlling for drinking level. In a parallel set of analyses, Omax also predicted drinking quantity and alcohol problems, although Omax was not a unique predictor of the latter. These results offer initial support for using AUC as an index of alcohol demand. Additional research is necessary to further validate this approach and to examine its utility in quantifying demand for other addictive substances such as tobacco and illicit drugs. PMID:25895013

  14. Elastic properties of spherically anisotropic piezoelectric composites

    NASA Astrophysics Data System (ADS)

    Wei, En-Bo; Gu, Guo-Qing; Poon, Ying-Ming

    2010-09-01

    Effective elastic properties of spherically anisotropic piezoelectric composites, whose spherically anisotropic piezoelectric inclusions are embedded in an infinite non-piezoelectric matrix, are theoretically investigated. Analytical solutions for the elastic displacements and the electric potentials under a uniform external strain are derived exactly. Taking into account of the coupling effects of elasticity, permittivity and piezoelectricity, the formula is derived for estimating the effective elastic properties based on the average field theory in the dilute limit. An elastic response mechanism is revealed, in which the effective elastic properties increase as inclusion piezoelectric properties increase and inclusion dielectric properties decrease. Moreover, a piezoelectric response mechanism, of which the effective piezoelectric response vanishes due to the symmetry of spherically anisotropic composite, is also disclosed.

  15. Skin elastic fibers in Williams syndrome.

    PubMed

    Dridi, S M; Ghomrasseni, S; Bonnet, D; Aggoun, Y; Vabres, P; Bodemer, C; Lyonnet, S; de Prost, Y; Fraitag, S; Pellat, B; Sidi, D; Godeau, G

    1999-11-19

    The elastin gene is consistently deleted in Williams syndrome and as this protein represents the major component of the elastic fibers of the dermis, we sought to investigate skin elastic fibers in Williams syndrome as a key to unraveling extracellular matrix disorganization in this condition. Both morphometric parameters analyzed by using automated image analysis and immunofluorescence labeling with monoclonal antibodies against elastin and fibrillin 1 showed a disorganized pre-elastic (oxytalan and elaunin) and mature elastic fibers in the dermis of 10 Williams syndrome patients compared with five healthy children and one patient with isolated supravalvular aortic stenosis. Skin biopsies in Williams syndrome patients provide a simple mean to elucidate extracellular matrix anomalies. Hopefully, this method could give clues to the understanding of the elastic network anomalies in this condition and even to the consequences of these latter on elasticity and resilience of other tissues such as the arterial tree. Copyright 1999 Wiley-Liss, Inc.

  16. Evaluation of a Hybrid Elastic EVA Glove

    NASA Technical Reports Server (NTRS)

    Korona, F. Adam; Akin, David

    2002-01-01

    The hybrid elastic design is based upon an American Society for Engineering Education (ASEE) glove designed by at the Space Systems Laboratory (SSL) in 1985. This design uses an elastic restraint layer instead of convolute joints to achieve greater dexterity and mobility during EVA (extravehicular activity). Two pilot studies and a main study were conducted using the hybrid elastic glove and 4000-series EMU (extravehicular activity unit) glove. Data on dexterity performance, joint range of motion, grip strength and perceived exertion was assessed for the EMU and hybrid elastic gloves with correlations to a barehanded condition. During this study, 30 test subjects performed multiple test sessions using a hybrid elastic glove and a 4000- series shuttle glove in a 4.3psid pressure environment. Test results to date indicate that the hybrid elastic glove performance is approximately similar to the performance of the 4000-series glove.

  17. Elastic, Conductive, Polymeric Hydrogels and Sponges

    PubMed Central

    Lu, Yun; He, Weina; Cao, Tai; Guo, Haitao; Zhang, Yongyi; Li, Qingwen; Shao, Ziqiang; Cui, Yulin; Zhang, Xuetong

    2014-01-01

    As a result of inherent rigidity of the conjugated macromolecular chains resulted from the delocalized π-electron system along the polymer backbone, it has been a huge challenge to make conducting polymer hydrogels elastic by far. Herein elastic and conductive polypyrrole hydrogels with only conducting polymer as the continuous phase have been simply synthesized in the indispensable conditions of 1) mixed solvent, 2) deficient oxidant, and 3) monthly secondary growth. The elastic mechanism and oxidative polymerization mechanism on the resulting PPy hydrogels have been discussed. The resulting hydrogels show some novel properties, e.g., shape memory elasticity, fast functionalization with various guest objects, and fast removal of organic infectants from aqueous solutions, all of which cannot be observed from traditional non-elastic conducting polymer counterparts. What's more, light-weight, elastic, and conductive organic sponges with excellent stress-sensing behavior have been successfully achieved via using the resulting polypyrrole hydrogels as precursors. PMID:25052015

  18. Evaluation of a Hybrid Elastic EVA Glove

    NASA Technical Reports Server (NTRS)

    Korona, F. Adam; Akin, David

    2002-01-01

    The hybrid elastic design is based upon an American Society for Engineering Education (ASEE) glove designed by at the Space Systems Laboratory (SSL) in 1985. This design uses an elastic restraint layer instead of convolute joints to achieve greater dexterity and mobility during EVA (extravehicular activity). Two pilot studies and a main study were conducted using the hybrid elastic glove and 4000-series EMU (extravehicular activity unit) glove. Data on dexterity performance, joint range of motion, grip strength and perceived exertion was assessed for the EMU and hybrid elastic gloves with correlations to a barehanded condition. During this study, 30 test subjects performed multiple test sessions using a hybrid elastic glove and a 4000- series shuttle glove in a 4.3psid pressure environment. Test results to date indicate that the hybrid elastic glove performance is approximately similar to the performance of the 4000-series glove.

  19. Demand Controlled Ventilation and Classroom Ventilation

    SciTech Connect

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2012-05-01

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling.

  20. Commercial Demand Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Commercial Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated through the synthesis and scenario development based on these components.

  1. Projecting Electricity Demand in 2050

    SciTech Connect

    Hostick, Donna J.; Belzer, David B.; Hadley, Stanton W.; Markel, Tony; Marnay, Chris; Kintner-Meyer, Michael C. W.

    2014-07-01

    This paper describes the development of end-use electricity projections and load curves that were developed for the Renewable Electricity (RE) Futures Study (hereafter RE Futures), which explored the prospect of higher percentages (30% - 90%) of total electricity generation that could be supplied by renewable sources in the United States. As input to RE Futures, two projections of electricity demand were produced representing reasonable upper and lower bounds of electricity demand out to 2050. The electric sector models used in RE Futures required underlying load profiles, so RE Futures also produced load profile data in two formats: 8760 hourly data for the year 2050 for the GridView model, and in 2-year increments for 17 time slices as input to the Regional Energy Deployment System (ReEDS) model. The process for developing demand projections and load profiles involved three steps: discussion regarding the scenario approach and general assumptions, literature reviews to determine readily available data, and development of the demand curves and load profiles.

  2. Employer Demands from Business Graduates

    ERIC Educational Resources Information Center

    McMurray, Stephen; Dutton, Matthew; McQuaid, Ronald; Richard, Alec

    2016-01-01

    Purpose: The purpose of this paper is to report on research carried out with employers to determine demand for business and management skills in the Scottish workforce. Design/methodology/approach: The research used a questionnaire in which employers were interviewed (either telephone or face to face), completed themselves and returned by e-mail,…

  3. Faculty Demand in Higher Education

    ERIC Educational Resources Information Center

    Rosenthal, Danielle

    2007-01-01

    The objective of this study is to identify the factors that shift the demand curve for faculty at not-for-profit private institutions. It is unique in that to the author's knowledge no other study has directly addressed the question of how the positive correlation between average faculty salaries and faculty-student ratios can be reconciled with…

  4. Towards Real Information on Demand.

    ERIC Educational Resources Information Center

    Barker, Philip

    The phrase "information on demand" is often used to describe situations in which digital electronic information can be delivered to particular points of need at times and in ways that are determined by the specific requirements of individual consumers or client groups. The advent of "mobile" computing equipment now makes the…

  5. Smart Buildings and Demand Response

    NASA Astrophysics Data System (ADS)

    Kiliccote, Sila; Piette, Mary Ann; Ghatikar, Girish

    2011-11-01

    Advances in communications and control technology, the strengthening of the Internet, and the growing appreciation of the urgency to reduce demand side energy use are motivating the development of improvements in both energy efficiency and demand response (DR) systems in buildings. This paper provides a framework linking continuous energy management and continuous communications for automated demand response (Auto-DR) in various times scales. We provide a set of concepts for monitoring and controls linked to standards and procedures such as Open Automation Demand Response Communication Standards (OpenADR). Basic building energy science and control issues in this approach begin with key building components, systems, end-uses and whole building energy performance metrics. The paper presents a framework about when energy is used, levels of services by energy using systems, granularity of control, and speed of telemetry. DR, when defined as a discrete event, requires a different set of building service levels than daily operations. We provide examples of lessons from DR case studies and links to energy efficiency.

  6. Employer Demands from Business Graduates

    ERIC Educational Resources Information Center

    McMurray, Stephen; Dutton, Matthew; McQuaid, Ronald; Richard, Alec

    2016-01-01

    Purpose: The purpose of this paper is to report on research carried out with employers to determine demand for business and management skills in the Scottish workforce. Design/methodology/approach: The research used a questionnaire in which employers were interviewed (either telephone or face to face), completed themselves and returned by e-mail,…

  7. The Evolving Demand for Skills.

    ERIC Educational Resources Information Center

    Greenspan, Alan

    From a macroeconomic perspective, the evolving demand for skills in the United States has been triggered by the accelerated expansion of computer and information technology, which has, in turn, brought significant changes to the workplace. Technological advances have made some wholly manual jobs obsolete. But even for many other workers, a rapidly…

  8. Commercial Demand Module - NEMS Documentation

    EIA Publications

    2017-01-01

    Documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Commercial Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated through the synthesis and scenario development based on these components.

  9. Demand Characteristics, Moods, and Helping

    ERIC Educational Resources Information Center

    Wispe, Lauren; And Others

    1977-01-01

    Procedures used in empathy-helping studies suggest results may be due to demand characteristics. Two studies were run to investigate especially the mood induction process. One reproduced the Aderman-Berkowitz main mood effects. Another showed that after seeing a help-non-help incident, mood effects were demonstrated only when Ss knew the research…

  10. Residential electricity demand in Arkansas

    NASA Astrophysics Data System (ADS)

    Resendez, Ileana M.

    This study analyzes residential electricity demand in Arkansas. Explanatory variables utilized include real per capita income, residential electricity price, heating degree days, cooling degree days, and residential natural gas price. The results indicate that the income effect dominates the substitution effect given a real personal income increase and a decline in real electricity rates in the state of Arkansas during the period under study.

  11. Inversion of elastic impedance for unconsolidated sediments

    USGS Publications Warehouse

    Lee, Myung W.

    2006-01-01

    Elastic properties of gas-hydrate-bearing sediments are important for quantifying gas hydrate amounts as well as discriminating the gas hydrate effect on velocity from free gas or pore pressure. This paper presents an elastic inversion method for estimating elastic properties of gas-hydrate-bearing sediments from angle stacks using sequential inversion of P-wave impedance from the zero-offset stack and S-wave impedance from the far-offset stack without assuming velocity ratio.

  12. Multi-spectral photoacoustic elasticity tomography

    PubMed Central

    Liu, Yubin; Yuan, Zhen

    2016-01-01

    The goal of this work was to develop and validate a spectrally resolved photoacoustic imaging method, namely multi-spectral photoacoustic elasticity tomography (PAET) for quantifying the physiological parameters and elastic modulus of biological tissues. We theoretically and experimentally examined the PAET imaging method using simulations and in vitro experimental tests. Our simulation and in vitro experimental results indicated that the reconstructions were quantitatively accurate in terms of sizes, the physiological and elastic properties of the targets. PMID:27699101

  13. Elastic scattering with weakly bound projectiles

    SciTech Connect

    Figueira, J. M.; Abriola, D.; Arazi, A.; Capurro, O. A.; Marti, G. V.; Martinez Heinmann, D.; Pacheco, A. J.; Testoni, J. E.; Barbara, E. de; Fernandez Niello, J. O.; Padron, I.; Gomes, P. R. S.; Lubian, J.

    2007-02-12

    Possible effects of the break-up channel on the elastic scattering threshold anomaly has been investigated. We used the weakly bound 6,7Li nuclei, which is known to undergo break-up, as projectiles in order to study the elastic scattering on a 27Al target. In this contribution we present preliminary results of these experiments, which were analyzed in terms of the Optical Model and compared with other elastic scattering data using weakly bound nuclei as projectile.

  14. Hummingbird tongues are elastic micropumps

    PubMed Central

    Rico-Guevara, Alejandro; Fan, Tai-Hsi; Rubega, Margaret A.

    2015-01-01

    Pumping is a vital natural process, imitated by humans for thousands of years. We demonstrate that a hitherto undocumented mechanism of fluid transport pumps nectar onto the hummingbird tongue. Using high-speed cameras, we filmed the tongue–fluid interaction in 18 hummingbird species, from seven of the nine main hummingbird clades. During the offloading of the nectar inside the bill, hummingbirds compress their tongues upon extrusion; the compressed tongue remains flattened until it contacts the nectar. After contact with the nectar surface, the tongue reshapes filling entirely with nectar; we did not observe the formation of menisci required for the operation of capillarity during this process. We show that the tongue works as an elastic micropump; fluid at the tip is driven into the tongue's grooves by forces resulting from re-expansion of a collapsed section. This work falsifies the long-standing idea that capillarity is an important force filling hummingbird tongue grooves during nectar feeding. The expansive filling mechanism we report in this paper recruits elastic recovery properties of the groove walls to load nectar into the tongue an order of magnitude faster than capillarity could. Such fast filling allows hummingbirds to extract nectar at higher rates than predicted by capillarity-based foraging models, in agreement with their fast licking rates. PMID:26290074

  15. Electron-Hydrogen Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.

    2004-01-01

    Scattering by single-electron systems is always of interest because the wave function of the target is known exactly. Various approximations have been employed to take into account distortion produced in the target. Among them are the method of polarized orbitals and the close coupling approximation. Recently, e-H and e-He+ S-wave scattering in the elastic region has been studied using the Feshbach projection operator formalism. In this approach, the usual Hartree-Fock and exchange potentials are augmented by an optical potential and the resulting phase shifts have rigorous lower bounds. Now this method is being applied to the e-H P-wave scattering in the elastic region. The number of terms in the Hylleraas-type wave function for the 1,3 P phase shifts is 84 and the resulting phase shifts (preliminary) are given. The results have been given up to five digits because to that accuracy they are rigorous lower bounds. They are in general agreement with the variational (VAR) results of Armstead, and those obtained from the intermediate energy R-matrix method (RM) of Scholz et al., and the finite element method (FEM) of Botero and Shertzer. The later two methods do not provide any bounds on phase shifts.

  16. Pneumatic Variable Series Elastic Actuator

    PubMed Central

    Zheng, Hao; Wu, Molei; Shen, Xiangrong

    2016-01-01

    Inspired by human motor control theory, stiffness control is highly effective in manipulation and human-interactive tasks. The implementation of stiffness control in robotic systems, however, has largely been limited to closed-loop control, and suffers from multiple issues such as limited frequency range, potential instability, and lack of contribution to energy efficiency. Variable-stiffness actuator represents a better solution, but the current designs are complex, heavy, and bulky. The approach in this paper seeks to address these issues by using pneumatic actuator as a variable series elastic actuator (VSEA), leveraging the compressibility of the working fluid. In this work, a pneumatic actuator is modeled as an elastic element with controllable stiffness and equilibrium point, both of which are functions of air masses in the two chambers. As such, for the implementation of stiffness control in a robotic system, the desired stiffness/equilibrium point can be converted to the desired chamber air masses, and a predictive pressure control approach is developed to control the timing of valve switching to obtain the desired air mass while minimizing control action. Experimental results showed that the new approach in this paper requires less expensive hardware (on–off valve instead of proportional valve), causes less control action in implementation, and provides good control performance by leveraging the inherent dynamics of the actuator. PMID:27354755

  17. Pneumatic Variable Series Elastic Actuator.

    PubMed

    Zheng, Hao; Wu, Molei; Shen, Xiangrong

    2016-08-01

    Inspired by human motor control theory, stiffness control is highly effective in manipulation and human-interactive tasks. The implementation of stiffness control in robotic systems, however, has largely been limited to closed-loop control, and suffers from multiple issues such as limited frequency range, potential instability, and lack of contribution to energy efficiency. Variable-stiffness actuator represents a better solution, but the current designs are complex, heavy, and bulky. The approach in this paper seeks to address these issues by using pneumatic actuator as a variable series elastic actuator (VSEA), leveraging the compressibility of the working fluid. In this work, a pneumatic actuator is modeled as an elastic element with controllable stiffness and equilibrium point, both of which are functions of air masses in the two chambers. As such, for the implementation of stiffness control in a robotic system, the desired stiffness/equilibrium point can be converted to the desired chamber air masses, and a predictive pressure control approach is developed to control the timing of valve switching to obtain the desired air mass while minimizing control action. Experimental results showed that the new approach in this paper requires less expensive hardware (on-off valve instead of proportional valve), causes less control action in implementation, and provides good control performance by leveraging the inherent dynamics of the actuator.

  18. Hummingbird tongues are elastic micropumps.

    PubMed

    Rico-Guevara, Alejandro; Fan, Tai-Hsi; Rubega, Margaret A

    2015-08-22

    Pumping is a vital natural process, imitated by humans for thousands of years. We demonstrate that a hitherto undocumented mechanism of fluid transport pumps nectar onto the hummingbird tongue. Using high-speed cameras, we filmed the tongue-fluid interaction in 18 hummingbird species, from seven of the nine main hummingbird clades. During the offloading of the nectar inside the bill, hummingbirds compress their tongues upon extrusion; the compressed tongue remains flattened until it contacts the nectar. After contact with the nectar surface, the tongue reshapes filling entirely with nectar; we did not observe the formation of menisci required for the operation of capillarity during this process. We show that the tongue works as an elastic micropump; fluid at the tip is driven into the tongue's grooves by forces resulting from re-expansion of a collapsed section. This work falsifies the long-standing idea that capillarity is an important force filling hummingbird tongue grooves during nectar feeding. The expansive filling mechanism we report in this paper recruits elastic recovery properties of the groove walls to load nectar into the tongue an order of magnitude faster than capillarity could. Such fast filling allows hummingbirds to extract nectar at higher rates than predicted by capillarity-based foraging models, in agreement with their fast licking rates. © 2015 The Author(s).

  19. Eulerian formulation of elastic rods

    NASA Astrophysics Data System (ADS)

    Huynen, Alexandre; Detournay, Emmanuel; Denoël, Vincent

    2016-06-01

    In numerous biological, medical and engineering applications, elastic rods are constrained to deform inside or around tube-like surfaces. To solve efficiently this class of problems, the equations governing the deflection of elastic rods are reformulated within the Eulerian framework of this generic tubular constraint defined as a perfectly stiff normal ringed surface. This reformulation hinges on describing the rod-deformed configuration by means of its relative position with respect to a reference curve, defined as the axis or spine curve of the constraint, and on restating the rod local equilibrium in terms of the curvilinear coordinate parametrizing this curve. Associated with a segmentation strategy, which partitions the global problem into a sequence of rod segments either in continuous contact with the constraint or free of contact (except for their extremities), this re-parametrization not only trivializes the detection of new contacts but also transforms these free boundary problems into classic two-points boundary-value problems and suppresses the isoperimetric constraints resulting from the imposition of the rod position at the extremities of each rod segment.

  20. Microscopic theory of rubber elasticity.

    PubMed

    Oyerokun, Folusho T; Schweizer, Kenneth S

    2004-05-15

    A microscopic integral equation theory of elasticity in polymer liquids and networks is developed which addresses the nonclassical problem of the consequences of interchain repulsive interactions and packing correlations on mechanical response. The theory predicts strain induced softening, and a nonclassical intermolecular contribution to the linear modulus. The latter is of the same magnitude as the classical single chain entropy contribution at low polymer concentrations, but becomes much more important in the melt state, and dominant as the isotropic-nematic liquid crystal phase transition is approached. Comparison of the calculated stress-strain curve and induced nematic order parameter with computer simulations show good agreement. A nearly quadratic dependence of the linear elastic modulus on segmental concentration is found, as well as a novel fractional power law dependence on degree of polymerization. Quantitative comparison of the theory with experiments on polydimethylsiloxane networks are presented and good agreement is found. However, a nonzero modulus in the long chain limit is not predicted since quenched chemical crosslinks and trapped entanglements are not explicitly taken into account. The theory is generalizable to treat the structure, thermodynamics and mechanical response of nematic elastomers.

  1. Electron-Hydrogen Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.

    2004-01-01

    Scattering by single-electron systems is always of interest because the wave function of the target is known exactly. Various approximations have been employed to take into account distortion produced in the target. Among them are the method of polarized orbitals and the close coupling approximation. Recently, e-H and e-He+ S-wave scattering in the elastic region has been studied using the Feshbach projection operator formalism. In this approach, the usual Hartree-Fock and exchange potentials are augmented by an optical potential and the resulting phase shifts have rigorous lower bounds. Now this method is being applied to the e-H P-wave scattering in the elastic region. The number of terms in the Hylleraas-type wave function for the 1,3 P phase shifts is 84 and the resulting phase shifts (preliminary) are given. The results have been given up to five digits because to that accuracy they are rigorous lower bounds. They are in general agreement with the variational (VAR) results of Armstead, and those obtained from the intermediate energy R-matrix method (RM) of Scholz et al., and the finite element method (FEM) of Botero and Shertzer. The later two methods do not provide any bounds on phase shifts.

  2. On implicit constitutive relations in elastic ferroelectrics

    NASA Astrophysics Data System (ADS)

    Arvanitakis, Antonios

    2017-10-01

    A considerable effort is being made to foster the use of implicit constitutive relations in mechanics of the continuous medium. From this point of view, the class of elastic bodies extends to a much larger category than the classical Cauchy and Green elastic bodies. In this work, a subclass of the recently proposed classes of electro-elastic bodies is taken into consideration to propose models for elastic ferroelectrics. These models, even though they are not based on thermodynamical arguments, seem capable enough to provide the hysteretic behavior of ferroelectric materials.

  3. Elastic moduli of pyrope rich garnets

    NASA Astrophysics Data System (ADS)

    Pandey, B. K.; Pandey, A. K.; Singh, C. K.

    2013-06-01

    The elastic properties of minerals depend on its composition, crystal structure, temperature and level of defects. The elastic parameters are important for the interpretation of the structure and composition of the garnet rich family. In present work we have calculated the elastic moduli such as isothermal bulk modulus, Young's modulus and Shear modulus over a wide range of temperature from 300 K to 1000 K by using Birch EOS and Poirrier Tarantola equation of state. The obtained results are compared with the experimental results obtained by measuring the elastic moduli of single crystal. The calculated results show that the logarithmic isothermal EOS does not cooperate well with experimental results.

  4. Nonlinear interaction of plane elastic waves

    SciTech Connect

    Korneev, V.A.; Nihei, K.T.; Myer, L.R.

    1998-06-01

    The paper presents basic first order results of nonlinear elastic theory by Murnaghan for elastic wave propagation in isotropic solids. The authors especially address the problem of resonant scattering of two collimated beams and present analytical solutions for amplitudes of all possible types of resonant interactions for elastic plane waves. For estimation of nonlinear scattered waves they use measured elastic parameters for sandstone. The most profound nonlinear effect is expected for interactions of two SH waves generating compressional P wave at sum frequency. Estimations show that nonlinear phenomena is likely to be observed in seismic data. Basic equations of nonlinear five-constant theory by Murnaghan are also presented.

  5. Faraday wave lattice as an elastic metamaterial.

    PubMed

    Domino, L; Tarpin, M; Patinet, S; Eddi, A

    2016-05-01

    Metamaterials enable the emergence of novel physical properties due to the existence of an underlying subwavelength structure. Here, we use the Faraday instability to shape the fluid-air interface with a regular pattern. This pattern undergoes an oscillating secondary instability and exhibits spontaneous vibrations that are analogous to transverse elastic waves. By locally forcing these waves, we fully characterize their dispersion relation and show that a Faraday pattern presents an effective shear elasticity. We propose a physical mechanism combining surface tension with the Faraday structured interface that quantitatively predicts the elastic wave phase speed, revealing that the liquid interface behaves as an elastic metamaterial.

  6. Rubber Elasticity in Highly Crosslinked Polyesters.

    DTIC Science & Technology

    Esters, *Polymers, *Elastic properties, Rubber, Propylene glycol , Maleic acid, Anhydrides, Phthalic acids, Mechanical properties, Molecular structure, Crosslinking(Chemistry), Polymerization, Styrenes, Temperature, Transition temperature, Molecular weight

  7. The alchemy of demand response: turning demand into supply

    SciTech Connect

    Rochlin, Cliff

    2009-11-15

    Paying customers to refrain from purchasing products they want seems to run counter to the normal operation of markets. Demand response should be interpreted not as a supply-side resource but as a secondary market that attempts to correct the misallocation of electricity among electric users caused by regulated average rate tariffs. In a world with costless metering, the DR solution results in inefficiency as measured by deadweight losses. (author)

  8. Addressing Energy Demand through Demand Response. International Experiences and Practices

    SciTech Connect

    Shen, Bo; Ghatikar, Girish; Ni, Chun Chun; Dudley, Junqiao; Martin, Phil; Wikler, Greg

    2012-06-01

    Demand response (DR) is a load management tool which provides a cost-effective alternative to traditional supply-side solutions to address the growing demand during times of peak electrical load. According to the US Department of Energy (DOE), demand response reflects “changes in electric usage by end-use customers from their normal consumption patterns in response to changes in the price of electricity over time, or to incentive payments designed to induce lower electricity use at times of high wholesale market prices or when system reliability is jeopardized.” 1 The California Energy Commission (CEC) defines DR as “a reduction in customers’ electricity consumption over a given time interval relative to what would otherwise occur in response to a price signal, other financial incentives, or a reliability signal.” 2 This latter definition is perhaps most reflective of how DR is understood and implemented today in countries such as the US, Canada, and Australia where DR is primarily a dispatchable resource responding to signals from utilities, grid operators, and/or load aggregators (or DR providers).

  9. An economic analysis of "demand" for food in baboons.

    PubMed

    Foltin, R W

    1991-11-01

    Responding of 6 adult male baboons (Papio c. anubis) was maintained under a fixed-ratio schedule of food reinforcement during daily 22-hr experimental sessions. Completion of the ratio requirement resulted in the delivery of a single 1-g food pellet; supplemental feeding was limited to a daily fruit ration. Ratio values were increased on Mondays, Wednesdays, and Fridays according to the following schedule: 2, 4, 8, 16, 32, 64, 96, 128. Responding under each ratio value was examined four times. Under the Fixed-Ratio 2 conditions, food intake ranged between 300 and 600 g. Ratios were increased for each baboon until food intake decreased to about 100 g (20% to 30% of Fixed-Ratio 2 intake). Increasing the response cost increased total time responding and total daily responding in all baboons, but this increase in responding was not sufficient to maintain stable food intake. Baboons responded between 90 and 180 min per day. The highest running response rates were observed under the Fixed-Ratio 2 and Fixed-Ratio 4 schedules. Running rate was similar across the larger ratio values (greater than Fixed-Ratio 8) but was lower than that observed under the Fixed-Ratio 2 and Fixed-Ratio 4 schedules. Similar results were observed the four times that each fixed-ratio value was tested. Intake as a function of cost was analyzed by fitting data to the nonlinear equation proposed by Hursh, Raslear, Shurtleff, Bauman, and Simmons (1988) for "demand" functions. Demand for food was inelastic over most of the ratio values until food intake decreased to 15% to 55% of baseline. The results indicate that demand functions are appropriate for the study of food intake in baboons, but also caution that intake at the cost when demand shifts from inelastic to elastic and its relationship to maximal intake should also be included in analyses of demand for a commodity.

  10. Heroin and saccharin demand and preference in rats.

    PubMed

    Schwartz, Lindsay P; Kim, Jung S; Silberberg, Alan; Kearns, David N

    2017-09-01

    Several recent studies have investigated the choice between heroin and a non-drug alternative reinforcer in rats. A common finding in these studies is that there are large individual differences in preference, with some rats preferring heroin and some preferring the non-drug alternative. The primary goal of the present study was to determine whether individual differences in how heroin or saccharin is valued, based on demand analysis, predicts choice. Rats lever-pressed for heroin infusions and saccharin reinforcers on fixed-ratio schedules. The essential value of each reinforcer was obtained from resulting demand curves. Rats were then trained on a mutually exclusive choice procedure where pressing one lever resulted in heroin and pressing another resulted in saccharin. After seven sessions of increased access to heroin or saccharin, rats were reexposed to the demand and choice procedures. Demand for heroin was more elastic than demand for saccharin (i.e., heroin had lower essential value than saccharin). When allowed to choose, most rats preferred saccharin. The essential value of heroin, but not saccharin, predicted preference. The essential value of both heroin and saccharin increased following a week of increased access to heroin, but similar saccharin exposure had no effect on essential value. Preference was unchanged after increased access to either reinforcer. Heroin-preferring rats differed from saccharin-preferring rats in how they valued heroin, but not saccharin. To the extent that choice models addiction-related behavior, these results suggest that overvaluation of opioids specifically, rather than undervaluation of non-drug alternatives, could identify susceptible individuals. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Testing simulation and structural models with applications to energy demand

    NASA Astrophysics Data System (ADS)

    Wolff, Hendrik

    2007-12-01

    This dissertation deals with energy demand and consists of two parts. Part one proposes a unified econometric framework for modeling energy demand and examples illustrate the benefits of the technique by estimating the elasticity of substitution between energy and capital. Part two assesses the energy conservation policy of Daylight Saving Time and empirically tests the performance of electricity simulation. In particular, the chapter "Imposing Monotonicity and Curvature on Flexible Functional Forms" proposes an estimator for inference using structural models derived from economic theory. This is motivated by the fact that in many areas of economic analysis theory restricts the shape as well as other characteristics of functions used to represent economic constructs. Specific contributions are (a) to increase the computational speed and tractability of imposing regularity conditions, (b) to provide regularity preserving point estimates, (c) to avoid biases existent in previous applications, and (d) to illustrate the benefits of our approach via numerical simulation results. The chapter "Can We Close the Gap between the Empirical Model and Economic Theory" discusses the more fundamental question of whether the imposition of a particular theory to a dataset is justified. I propose a hypothesis test to examine whether the estimated empirical model is consistent with the assumed economic theory. Although the proposed methodology could be applied to a wide set of economic models, this is particularly relevant for estimating policy parameters that affect energy markets. This is demonstrated by estimating the Slutsky matrix and the elasticity of substitution between energy and capital, which are crucial parameters used in computable general equilibrium models analyzing energy demand and the impacts of environmental regulations. Using the Berndt and Wood dataset, I find that capital and energy are complements and that the data are significantly consistent with duality

  12. Alcohol price elasticities in control and license states in the United States, 1982-99.

    PubMed

    Trolldal, Björn; Ponicki, William

    2005-08-01

    The demand for alcohol has been demonstrated repeatedly to be sensitive to price changes. However, estimated price elasticities vary by study region and over time. One explanation for these variations might be that different countries or parts of countries have had different alcohol control systems. The hypothesis addressed in this study was that a regulated market leads to higher transaction costs associated with purchasing alcohol, which in turn increases the full price of the beverages (the nominal cash price plus transaction costs). As a result, the cash price of alcohol represents a smaller part of the full price in a highly regulated market. Assuming that customers respond primarily to changes in full price, the demand for alcohol should be less sensitive to changes in cash price where regulation is stricter. This study examined whether variations in price elasticities were a function of the different regulatory systems in control and license states in the United States during the period 1982-99. Time-series cross-sectional analyses (in 50 states over 18 years) were conducted. Elasticities were estimated using a multiplicative model based upon first-differences of time-series within states. Disposable income and other socio-demographic variables were used as control variables. All data were obtained from archival sources. The demand for spirits and beer were significantly more sensitive to price changes in license states than in control states. The estimated price elasticity for wine sales was also somewhat larger in license states, but not significantly so. The lower price elasticities for spirits and beer in the control states support the hypothesis that customers respond primarily to changes in the full price of alcohol.

  13. Advertising increases demand for vasectomy.

    PubMed

    Mehta, M; Mckenzie, M

    1996-01-01

    The recent evaluation of a 2-year no-scalpel vasectomy (NSV) training program providing on-site, hands-on training for physicians working in 43 publicly funded health centers in 17 states found that demand for vasectomy in low-income and minority communities in the US increased following the implementation of innovative advertising strategies. The program also provided sites with surgical instruments, training materials, a press kit, and some help with public information activities. Participating clinics used a range of formal and informal advertising strategies, including radio and printed advertisements, to inform potential clients about vasectomy services. Many interested clients presented to clinics to undergo vasectomy once they had been made aware of the service and its availability. Several providers even stated that advertising caused the demand for vasectomy to exceed their capacity to provide services. The provision of low- or no-cost procedures helped to attract new clients.

  14. Diffusion nearby elastic cell membranes

    NASA Astrophysics Data System (ADS)

    Daddi-Moussa-Ider, Abdallah; Guckenberger, Achim; Gekle, Stephan

    2016-11-01

    The physical approach of a small particle to the cell membrane represents the crucial step before active internalization and is governed by Brownian diffusion. Using a fully analytical theory, we show that the stretching and bending of cell membranes induces a long-lived subdiffusive behavior on the nearby particle. Such behavior is qualitatively different from the normal diffusion in a bulk fluid or near a hard-wall. the scaling exponent of the mean-square displacement can go as low as 0.87 in the perpendicular and 0.92 in the parallel direction. Moreover, we investigate the hydrodynamic interaction between two particles finding that the steady motion of two particles towards an elastic membrane possessing only shearing resistance leads to attractive interaction in contrast to the hard-wall case where the interaction is known to be repulsive. Our analytical predictions are compared with boundary-integral simulations where an excellent agreement is obtained.

  15. High elastic modulus polymer electrolytes

    DOEpatents

    Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel

    2013-10-22

    A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics.

  16. Elastic Suppression of Viscous Fingering

    NASA Astrophysics Data System (ADS)

    Peng, Gunnar; Lister, John

    2016-11-01

    Consider peeling an elastic tape or beam away from a rigid base to which it is stuck by a film of viscous liquid. The peeling motion requires air to invade the viscous liquid and is thus susceptible to the Saffman-Taylor fingering instability. We analyse the fundamental travelling-wave solution and show that the advancing air-liquid interface remains linearly stable at higher capillary numbers than in a standard Hele-Shaw cell. A short-wavelength expansion yields an analytical expression for the growth rate which is valid for all unstable modes throughout the parameter space, allowing us to identify and quantify four distinct physical mechanisms that each help suppress the instability. Applying our method to the experiments by Pihler-Puzovic et al. (2012) reveals that the radial geometry and time-variation stabilize the system further.

  17. Elasticity of polymeric nanocolloidal particles

    NASA Astrophysics Data System (ADS)

    Riest, Jonas; Athanasopoulou, Labrini; Egorov, Sergei A.; Likos, Christos N.; Ziherl, Primož

    2015-11-01

    Softness is an essential mechanical feature of macromolecular particles such as polymer-grafted nanocolloids, polyelectrolyte networks, cross-linked microgels as well as block copolymer and dendrimer micelles. Elasticity of individual particles directly controls their swelling, wetting, and adsorption behaviour, their aggregation and self-assembly as well as structural and rheological properties of suspensions. Here we use numerical simulations and self-consistent field theory to study the deformation behaviour of a single spherical polymer brush upon diametral compression. We observe a universal response, which is rationalised using scaling arguments and interpreted in terms of two coarse-grained models. At small and intermediate compressions the deformation can be accurately reproduced by modelling the brush as a liquid drop, whereas at large compressions the brush behaves as a soft ball. Applicable far beyond the pairwise-additive small-strain regime, the models may be used to describe microelasticity of nanocolloids in severe confinement including dense disordered and crystalline phases.

  18. Occupational Demand in Minnesota for 1973.

    ERIC Educational Resources Information Center

    Copa, George H.; Irvin, Donald E., Jr.

    Effective planning of vocational education programs requires information about both the educational demand of individuals and the manpower demands of business and industry. Two characteristics of the manpower demand in Minnesota which are defined and estimated in this report are occupational demand, the total number of employment positions in a…

  19. 12 CFR 561.16 - Demand accounts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Demand accounts. 561.16 Section 561.16 Banks... AFFECTING ALL SAVINGS ASSOCIATIONS § 561.16 Demand accounts. The term demand accounts means non-interest-bearing demand deposits that are subject to check or to withdrawal or transfer on negotiable or...

  20. Physical Demands Study - Focus Groups

    DTIC Science & Technology

    2015-10-26

    should be selected and trained for a MOS only after careful consideration of their physical ability to perform the critical tasks of the job...However, the U.S. Army does not currently select Soldiers for a MOS based on their physical capabilities. This is problematic because training recruits...each Combat Arms MOS in both training and deployed environments. Purpose 2: To ensure that the minimum standards for each physically demanding task

  1. Disruptive innovation: the demand side.

    PubMed

    Havighurst, Clark C

    2008-01-01

    The notion of disruptive innovation provides a welcome framework for considering the prospects for low-cost alternatives in American medicine. Such innovations as have been seen, however, are largely the result of demand by patients paying their own bills because they have high-deductible coverage or are uninsured. Many other cost-saving innovations are discouraged by financing systems that are themselves largely immune to competition from disruptive innovators.

  2. Reversible simulations of elastic collisions

    SciTech Connect

    Perumalla, Kalyan S.; Protopopescu, Vladimir A.

    2013-05-01

    Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multi-particle, collisions. We develop a new algorithm that recovers the pre-collision state from the post-collision state of the system, across a series of consecutive collisions, \\textit{with essentially no memory overhead}. The challenge in achieving reversibility for an n-particle collision (where, in general, n<< N) arises from the presence of nd-d-1 degrees of freedom (arbitrary angles) during each collision, as well as from the complex geometrical constraints placed on the colliding particles. To reverse the collisions in a traditional simulation setting, all of the particular realizations of these degrees of freedom (angles) during the forward simulation must be tracked. This requires memory proportional to the number of collisions, which grows very fast with N and d, thereby severely limiting the \\textit{de facto} applicability of the scheme. This limitation is addressed here by first performing a pseudo-randomization of angles, which ensures determinism in the reverse path for any values of n and d. To address the more difficult problem of geometrical and dynamic constraints, a new approach is developed which correctly samples the constrained phase space. Upon combining the pseudo-randomization with correct phase space sampling, perfect reversibility of collisions is achieved, as illustrated for n<=3, d=2, and n=2, d=3. This result enables, for the first time, reversible simulations of elastic collisions with essentially zero memory accumulation. In principle, the approach presented here could be generalized to larger values of n, which would be of definite interest for molecular dynamics simulations at high densities.

  3. Demand for radiotherapy in Spain.

    PubMed

    Rodríguez, A; Borrás, J M; López-Torrecilla, J; Algara, M; Palacios-Eito, A; Gómez-Caamaño, A; Olay, L; Lara, P C

    2017-02-01

    Assessing the demand for radiotherapy in Spain based on existing evidence to estimate the human resources and equipment needed so that every person in Spain has access to high-quality radiotherapy when they need it. We used data from the European Cancer Observatory on the estimated incidence of cancer in Spain in 2012, along with the evidence-based indications for radiotherapy developed by the Australian CCORE project, to obtain an optimal radiotherapy utilisation proportion (OUP) for each tumour. About 50.5 % of new cancers in Spain require radiotherapy at least once over the course of the disease. Additional demand for these services comes from reradiation therapy and non-melanoma skin cancer. Approximately, 25-30 % of cancer patients with an indication for radiotherapy do not receive it due to factors that include access, patient preference, familiarity with the treatment among physicians, and especially resource shortages, all of which contribute to its underutilisation. Radiotherapy is underused in Spain. The increasing incidence of cancer expected over the next decade and the greater frequency of reradiations necessitate the incorporation of radiotherapy demand into need-based calculations for cancer services planning.

  4. Energy demand and population change.

    PubMed

    Allen, E L; Edmonds, J A

    1981-09-01

    During the post World War 2 years energy consumption has grown 136% while population grew about 51%; per capita consumption of energy expanded, therefore, about 60%. For a given population size, demographic changes mean an increase in energy needs; for instance the larger the group of retirement age people, the smaller their energy needs than are those for a younger group. Estimates indicate that by the year 2000 the energy impact will be toward higher per capita consumption with 60% of the population in the 19-61 age group of workers. Rising female labor force participation will increase the working group even more; it has also been found that income and energy grow at a proportional rate. The authors predict that gasoline consumption within the US will continue to rise with availability considering the larger number of female drivers and higher per capita incomes. The flow of illegal aliens (750,000/year) will have a major impact on income and will use greater amounts of energy than can be expected. A demographic change which will lower energy demands will be the slowdown of the rate of household formation caused by the falling number of young adults. The response of energy demand to price changes is small and slow but incomes play a larger role as does the number of personal automobiles and social changes affecting household formation. Households, commercial space, transportation, and industry are part of every demand analysis and population projections play a major role in determining these factors.

  5. Automation of energy demand forecasting

    NASA Astrophysics Data System (ADS)

    Siddique, Sanzad

    Automation of energy demand forecasting saves time and effort by searching automatically for an appropriate model in a candidate model space without manual intervention. This thesis introduces a search-based approach that improves the performance of the model searching process for econometrics models. Further improvements in the accuracy of the energy demand forecasting are achieved by integrating nonlinear transformations within the models. This thesis introduces machine learning techniques that are capable of modeling such nonlinearity. Algorithms for learning domain knowledge from time series data using the machine learning methods are also presented. The novel search based approach and the machine learning models are tested with synthetic data as well as with natural gas and electricity demand signals. Experimental results show that the model searching technique is capable of finding an appropriate forecasting model. Further experimental results demonstrate an improved forecasting accuracy achieved by using the novel machine learning techniques introduced in this thesis. This thesis presents an analysis of how the machine learning techniques learn domain knowledge. The learned domain knowledge is used to improve the forecast accuracy.

  6. A Methodology for Estimating Large-Customer Demand Response MarketPotential

    SciTech Connect

    Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers,Peter

    2007-08-01

    Demand response (DR) is increasingly recognized as an essential ingredient to well-functioning electricity markets. DR market potential studies can answer questions about the amount of DR available in a given area and from which market segments. Several recent DR market potential studies have been conducted, most adapting techniques used to estimate energy-efficiency (EE) potential. In this scoping study, we: reviewed and categorized seven recent DR market potential studies; recommended a methodology for estimating DR market potential for large, non-residential utility customers that uses price elasticities to account for behavior and prices; compiled participation rates and elasticity values from six DR options offered to large customers in recent years, and demonstrated our recommended methodology with large customer market potential scenarios at an illustrative Northeastern utility. We observe that EE and DR have several important differences that argue for an elasticity approach for large-customer DR options that rely on customer-initiated response to prices, rather than the engineering approaches typical of EE potential studies. Base-case estimates suggest that offering DR options to large, non-residential customers results in 1-3% reductions in their class peak demand in response to prices or incentive payments of $500/MWh. Participation rates (i.e., enrollment in voluntary DR programs or acceptance of default hourly pricing) have the greatest influence on DR impacts of all factors studied, yet are the least well understood. Elasticity refinements to reflect the impact of enabling technologies and response at high prices provide more accurate market potential estimates, particularly when arc elasticities (rather than substitution elasticities) are estimated.

  7. Celestial mechanics of elastic bodies II

    NASA Astrophysics Data System (ADS)

    Beig, Robert; Schmidt, Bernd G.

    2017-04-01

    We construct time independent configurations describing a small elastic body moving in a circular orbit in the Schwarzschild spacetime. These configurations are relativistic versions of Newtonian solutions constructed by us previously. In the process we simplify and sharpen previous results of ours concerning elastic bodies in rigid rotation.

  8. Study of Nonlinear Oscillations of Elastic Membrane

    DTIC Science & Technology

    2006-09-26

    Nonlinear Elastic Membrane Oscillations by Eigenfunction Expansion, WSEAS Transactions of Systems, 3 (4) (2004), 1430-1435. 2.V. Varlamov, Convolution...proceedings 1. A. Balogh and V. Varlamov, Analysis of Nonlinear Elastic Membrane Oscillations by Eigenfunction Expansion, 6th WSEAS International...Eigenfunction Expansion, 6th WSEAS International Conference on Algorithms, Scientific Computing, Modelling and Simulation, Cancun, Mexico, May 12--15

  9. Molecular pathology of the elastic fibers.

    PubMed

    Christiano, A M; Uitto, J

    1994-11-01

    Elastic fibers form a network that contributes to the elasticity and resilience of tissues such as the skin. Histopathologic and ultrastructural abnormalities in the elastic fibers have been observed in several diseases of the skin and other tissues. Recent cloning of several genes involved in elastic fiber architecture has lead to the approach of the study of elastic fiber genodermatoses through molecular analysis. However, in genodermatoses, such as pseudoxanthoma elasticum, many of the genes encoding elastic fiber components have been excluded by genetic linkage analysis. In recent years, mutations in several of the genes encoding elastic fiber proteins have been demonstrated in other diseases. These include mutations in the fibrillin 1 gene in the Marfan syndrome, and genetic linkage of congenital contractural arachnodactyly to fibrillin 2, and, most recently, demonstration of abnormalities in the Menkes syndrome gene in X-linked cutis laxa. The first disorders to involve mutations in the elastin gene itself are, surprisingly, cardiovascular and neurobehavioral disorders, such as supravalvular aortic stenosis and Williams syndrome. These findings suggest that additional, as yet undiscovered, components of the elastic fiber network in the skin may hold the key to unraveling the molecular basis of the elastin-related genodermatoses.

  10. Simulation and control problems in elastic robots

    NASA Technical Reports Server (NTRS)

    Tadikonda, S. S. K.; Baruh, H.

    1989-01-01

    Computational issues associated with modeling and control of robots with revolute joints and elastic arms are considered. A manipulator with one arm and pinned at one end is considered to investigate various aspects of the modeling procedure and the model, and the effect of coupling between the rigid-body and the elastic motions. The rigid-body motion of a manipulator arm is described by means of a reference frame attached to the shadow beam, and the linear elastic operator denoting flexibility is defined with respect to this reference frame. The small elastic motion assumption coupled with the method of assumed modes is used to model the elasticity in the arm. It is shown that only terms up to quadratic in these model amplitudes need to be retained. An important aspect of the coupling between the rigid-body and the elastic motion is the centrifugal stiffening effect. This effect stiffens the elastic structure, as to be expected on physical grounds, gives rise to a time-varying inertia term for the rigid-body motion, and, in general, results in an effective inertia term smaller than the rigid-body inertia term. Simulation results are presented for an elastic beam pinned at one end and free at the other, and rotating in a horizontal plane, and control issues such as the order of the model, number of sensors, and modal extraction are examined within this context.

  11. 7 CFR 29.6013 - Elasticity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Elasticity. 29.6013 Section 29.6013 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6013 Elasticity. The flexible, springy nature of the tobacco leaf...

  12. Ultrasonic System Measures Elastic Properties Of Composites

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Mal, Ajit K.

    1993-01-01

    Measurements with leaky Lamb waves yield data on properties and defects of panels. System nondestructively measures elastic properties of, and defects in, panel of laminated fiber/matrix material. Ultrasonic transducers operating in pitch/catch mode excite and detect leaky Lamb waves in specimen. Elastic properties of specimen and defects within it characterized from dispersion curves of Lamb waves.

  13. An improved scheduled traffic model utilizing bandwidth splitting in elastic optical networks

    NASA Astrophysics Data System (ADS)

    Vyas, Upama; Prakash, Shashi

    2016-07-01

    The surge of traffic in today's networks gave birth to elastic optical networking paradigm. In this paper, first we propose to use the scheduled traffic model (STM) in elastic optical networks (EONs) to ensure guaranteed availability of resources to demands which enter into the network with a predetermined start and end times. In optical networks, such demands are referred to as scheduled lightpath demands (SLDs). To increase the amount of bandwidth accepted in network, next we introduce a time aware routing and spectrum assignment (TA-RSA) approach. We observed that provisioning of bulky SLDs has become more challenging in EONs due to enforcement of RSA constraints. To address this challenge, we improve the proposed STM and designed three heuristics for its implementation in EONs. In this work, we collectively refer to these heuristics as bandwidth segmented RSA (BSRSA). The improved STM (iSTM) allows splitting of SLDs in bandwidth dimension by utilizing the knowledge of attributes viz. demand holding time, overlapping in time and bandwidth requested by SLDs. Our numerical results show that BSRSA consistently outperformed over TA-RSA under all distinctive experimental cases that we considered and achieved fairness in serving heterogeneous bandwidth SLDs. The impact of splitting on the number and capacity of transponders at nodes is also gauged. It is observed that ingenious splitting of demands increases the number of resources (on links and nodes) used, and their utilization, leading to an increase in bandwidth accepted in the network.

  14. An analysis of long and medium-haul air passenger demand, volume 1

    NASA Technical Reports Server (NTRS)

    Eriksen, S. E.

    1978-01-01

    A basic model was developed which is a two equation pair econometric system in which air passenger demand and airline level-of-service are the endogenous variables. The model aims to identify the relationship between each of these two variables and its determining factors, and to identify the interaction of demand and level-of-service with each other. The selected variable for the measure of air passenger traffic activity in a given pair market is defined as the number of passengers in a given time that originate in one region and fly to the other region for purposes other than to make a connection to a third region. For medium and long haul markets, the model seems to perform better for larger markets. This is due to a specification problem regarding the route structure variable. In larger markets, a greater percentage of nonlocal passengers are accounted for by this variable. Comparing the estimated fare elasticities of long and medium haul markets, it appears that air transportation demand is more price elastic in longer haul markets. Long haul markets demand will saturate with a fewer number of departures than will demand in medium haul markets.

  15. The Effect of Temperature on the Electricity Demand: An Empirical Investigation

    NASA Astrophysics Data System (ADS)

    Kim, H.; Kim, I. G.; Park, K. J.; Yoo, S. H.

    2015-12-01

    This paper attempts to estimate the electricity demand function in Korea with quarterly data of average temperature, GDP and electricity price over the period 2005-2013. We apply lagged dependent variable model and ordinary least square method as a robust approach to estimating the parameters of the electricity demand function. The results show that short-run price and income elasticities of the electricity demand are estimated to be -0.569 and 0.631 respectively. They are statistically significant at the 1% level. Moreover, long-run income and price elasticities are estimated to be 1.589 and -1.433 respectively. Both of results reveal that the demand for electricity demand is about 15.2℃. It is shown that power of explanation and goodness-of-fit statistics are improved in the use of the lagged dependent variable model rather than conventional model. Acknowledgements: This research was carried out as a part of "Development and application of technology for weather forecast" supported by the 2015 National Institute of Meteorological Research (NIMR) in the Korea Meteorological Administration.

  16. Supplier-induced demand: re-examining identification and misspecification in cross-sectional analysis.

    PubMed

    Peacock, Stuart J; Richardson, Jeffrey R J

    2007-09-01

    This paper re-examines criticisms of cross-sectional methods used to test for supplier-induced demand (SID) and re-evaluates the empirical evidence using data from Australian medical services. Cross-sectional studies of SID have been criticised on two grounds. First, and most important, the inclusion of the doctor supply in the demand equation leads to an identification problem. This criticism is shown to be invalid, as the doctor supply variable is stochastic and depends upon a variety of other variables including the desirability of the location. Second, cross-sectional studies of SID fail diagnostic tests and produce artefactual findings due to model misspecification. Contrary to this, the re-evaluation of cross-sectional Australian data indicate that demand equations that do not include the doctor supply are misspecified. Empirical evidence from the re-evaluation of Australian medical services data supports the notion of SID. Demand and supply equations are well specified and have very good explanatory power. The demand equation is identified and the desirability of a location is an important predictor of the doctor supply. Results show an average price elasticity of demand of 0.22 and an average elasticity of demand with respect to the doctor supply of 0.46, with the impact of SID becoming stronger as the doctor supply rises. The conclusion we draw from this paper is that two of the main criticisms of the empirical evidence supporting the SID hypothesis have been inappropriately levelled at the methods used. More importantly, SID provides a satisfactory, and robust, explanation of the empirical data on the demand for medical services in Australia.

  17. Breakdown of elasticity in amorphous solids

    NASA Astrophysics Data System (ADS)

    Biroli, Giulio; Urbani, Pierfrancesco

    2016-12-01

    What characterizes a solid is the way that it responds to external stresses. Ordered solids, such as crystals, exhibit an elastic regime followed by a plastic regime, both understood microscopically in terms of lattice distortion and dislocations. For amorphous solids the situation is instead less clear, and the microscopic understanding of the response to deformation and stress is a very active research topic. Several studies have revealed that even in the elastic regime the response is very jerky at low temperature, resembling very much the response of disordered magnetic materials. Here we show that in a very large class of amorphous solids this behaviour emerges upon decreasing temperature, as a phase transition, where standard elastic behaviour breaks down. At the transition all nonlinear elastic moduli diverge and standard elasticity theory no longer holds. Below the transition, the response to deformation becomes history- and time-dependent.

  18. Active Elasticity of Gels with Contractile Cells

    NASA Astrophysics Data System (ADS)

    Zemel, A.; Bischofs, I. B.; Safran, S. A.

    2006-09-01

    Cells play an active role in the maintenance of mechanical homeostasis within tissues and their response to elastic forces is important for tissue engineering. We predict the collective response of an ensemble of contractile cells in a three-dimensional elastic medium to externally applied strain fields. Motivated by experiment, we model the cells as polarizable force dipoles that change their orientation in response to the local elastic strain. The analogy between the mechanical response of these systems and the dielectric response of polar molecules is used to calculate the elastic response function. We use this analogy to evaluate the average cell orientation, the mean polarization stress, and the effective elastic constants of the material, as a function of the cell concentration and matrix properties.

  19. Traveling Lamb wave in elastic metamaterial layer

    NASA Astrophysics Data System (ADS)

    Shu, Haisheng; Xu, Lihuan; Shi, Xiaona; Zhao, Lei; Zhu, Jie

    2016-10-01

    The propagation of traveling Lamb wave in single layer of elastic metamaterial is investigated in this paper. We first categorized the traveling Lamb wave modes inside an elastic metamaterial layer according to different combinations (positive or negative) of effective medium parameters. Then the impacts of the frequency dependence of effective parameters on dispersion characteristics of traveling Lamb wave were studied. Distinct differences could be observed when comparing the traveling Lamb wave along an elastic metamaterial layer with one inside the traditional elastic layer. We further examined in detail the traveling Lamb wave mode supported in elastic metamaterial layer, when the effective P and S wave velocities were simultaneously imaginary. It was found that the effective modulus ratio is the key factor for the existence of special traveling wave mode, and the main results were verified by FEM simulations from two levels: the level of effective medium and the level of microstructure unit cell.

  20. Piezoresistive Sensor with High Elasticity Based on 3D Hybrid Network of Sponge@CNTs@Ag NPs.

    PubMed

    Zhang, Hui; Liu, Nishuang; Shi, Yuling; Liu, Weijie; Yue, Yang; Wang, Siliang; Ma, Yanan; Wen, Li; Li, Luying; Long, Fei; Zou, Zhengguang; Gao, Yihua

    2016-08-31

    Pressure sensors with high elasticity are in great demand for the realization of intelligent sensing, but there is a need to develope a simple, inexpensive, and scalable method for the manufacture of the sensors. Here, we reported an efficient, simple, facile, and repeatable "dipping and coating" process to manufacture a piezoresistive sensor with high elasticity, based on homogeneous 3D hybrid network of carbon nanotubes@silver nanoparticles (CNTs@Ag NPs) anchored on a skeleton sponge. Highly elastic, sensitive, and wearable sensors are obtained using the porous structure of sponge and the synergy effect of CNTs/Ag NPs. Our sensor was also tested for over 2000 compression-release cycles, exhibiting excellent elasticity and cycling stability. Sensors with high performance and a simple fabrication process are promising devices for commercial production in various electronic devices, for example, sport performance monitoring and man-machine interfaces.

  1. Assessing economic and demographic factors that influence United States dairy demand.

    PubMed

    Davis, C G; Yen, S T; Dong, D; Blayney, D P

    2011-07-01

    Low-fat dairy products are key components of a healthy diet for all Americans. As the USDA increases its focus on nutrition and healthy eating, it is important to understand the underlying demands for dairy products, both the healthy and the less healthy ones. The consumption of fluid milk products has decreased over the last decade, whereas milk used for manufactured dairy products such as cheese, ice cream, yogurt, and butter, and for use as an ingredient in other food products, has risen. The objective of this study is to determine the effects of changes in demographic variables, retail prices, and total dairy expenditure on at-home consumption of dairy products, using purchase data from Nielsen 2007 Homescan (ACNielsen, New York, NY) data. To derive the demand elasticities for 16 products, a censored Almost Ideal Demand System model is used. Results reveal that demographic variables do have effects on the purchase of the 16 products, and own-price elasticities are 1 or greater for all 16 products for both uncompensated and compensated elasticities except 4: ice cream, refrigerated yogurt, processed cheese, and margarine. A substitution relationship exists among all fluid milk categories, natural and processed cheese, low-fat ice cream, and refrigerated yogurt, butter, and margarine.

  2. Analysis for Elasticity of Rainfall - Discharge - Pollutant Loads considering Climate Change in Nakdong River Basin

    NASA Astrophysics Data System (ADS)

    Shon, T.; Kim, M.; Jang, Y.; Yi, J.; Shin, H.

    2012-12-01

    Climate change has been settled as pending issues to consider water resources and environment all over the world. However, scientific and quantitative assessment methods of climate change have never been standardized. When South Korea headed toward water deficiency nation, the study is not only required analysis of atmospheric or hydrologic factors, but also demanded analysis of correlation with water quality environment factors to gain management policies about climate change. Therefore, this study explored appropriate monthly rainfall-discharge elasticity in chosen 41 unit watersheds in Nakdong river which is one of the most important basin in Korea and applied monitored discharge data in 2004 to 2008 with monthly rainfall that estimated area rainfall . And each unit watershed drew elasticity between discharge and loads such as BOD, COD, SS, TN, and TP. Elasticity of monthly rainfall and discharge has estimated similarly value between total average and upstream, midstream and downstream average. And Elasticity of discharge and loads has estimated high value of all factors. Especially elasticity of discharge and SS loads is the highest value of all factors. Afterwards, this study will be continued to try different factors considerations in the near future and expected deepen research to overcome and improve limitation in this study.

  3. Static test induced loads verification beyond elastic limit

    NASA Technical Reports Server (NTRS)

    Verderaime, V.; Harrington, F.

    1996-01-01

    Increasing demands for reliable and least-cost high-performance aerostructures are pressing design analyses, materials, and manufacturing processes to new and narrowly experienced performance and verification technologies. This study assessed the adequacy of current experimental verification of the traditional binding ultimate safety factor which covers rare events in which no statistical design data exist. Because large high-performance structures are inherently very flexible, boundary rotations and deflections under externally applied loads approaching fracture may distort their transmission and unknowingly accept submarginal structures or prematurely fracturing reliable ones. A technique was developed, using measured strains from back-to-back surface mounted gauges, to analyze, define, and monitor induced moments and plane forces through progressive material changes from total-elastic to total-inelastic zones within the structural element cross section. Deviations from specified test loads are identified by the consecutively changing ratios of moment-to-axial load.

  4. Static test induced loads verification beyond elastic limit

    NASA Technical Reports Server (NTRS)

    Verderaime, V.; Harrington, F.

    1996-01-01

    Increasing demands for reliable and least-cost high performance aerostructures are pressing design analyses, materials, and manufacturing processes to new and narrowly experienced performance and verification technologies. This study assessed the adequacy of current experimental verification of the traditional binding ultimate safety factor which covers rare events in which no statistical design data exist. Because large, high-performance structures are inherently very flexible, boundary rotations and deflections under externally applied loads approaching fracture may distort their transmission and unknowingly accept submarginal structures or prematurely fracturing reliable ones. A technique was developed, using measured strains from back-to-back surface mounted gauges, to analyze, define, and monitor induced moments and plane forces through progressive material changes from total-elastic to total inelastic zones within the structural element cross section. Deviations from specified test loads are identified by the consecutively changing ratios of moment-to-axial load.

  5. Evaluation of Demand Prediction Techniques

    DTIC Science & Technology

    1987-03-01

    Road Bethesda, Maryland 20817 5886 JiZ A q C64 ACKNOWLEDGMENTS Robert Arnberg of LMI deserves credit for assembling many files cf D041 data for...the best techniques of those we studied. • Use of a Poisson or constant variance-to-mean ratio (VMR) leads to poor allocation of resources. Treating...the program element is not in the D041 record or is zero for some quarters with positive demand, or has apparent errors that lead to a less stable

  6. Unifying the criteria of elastic stability of solids.

    PubMed

    Wang, Hao; Li, Mo

    2012-06-20

    The elastic stability criterion formulated by Born is based on the convexity requirement of the equilibrium free energy F of a stress-free crystal under small strain fluctuation, that demands the elastic constant tensor C to be positive definite, |C| > 0. For a crystal subject to an external stress, Hill specifies that for the crystal to be stable, the difference between its internal energy change δE and the work done to the system δW must be positive, i.e. δE - δW > 0. Polanyi, Frenkel, and Orowan proposed a different stability criterion based on stress increment for a loaded system, τ(ε + Δε) - τ(ε) > 0 until the limit is reached at dτ/dε = 0. Although known empirically, the formal connection between the different criteria has not been established rigorously. Using finite deformation theory, we show quite simply that the different formulations of the stability criteria originate from the same necessary condition for the convexity of the free energy of the system subject to external loading, f = F - W. However, in practice caution must be taken in implementation of the different criteria; they may lead to quite different results, especially when stability bifurcation occurs.

  7. Displacement decomposition ACO based preconditioning of FEM elasticity systems

    NASA Astrophysics Data System (ADS)

    Sviercoski, R. F.; Margenov, S.

    2013-10-01

    Computational simulations of multiscale deformable porous media are routinely encountered as a part of research and development activities in a number of engineering, environmental and biomedical fields. The efficiency of multilevel iterative solution of such problems is a challenging topic on numerical methods for large-scale scientific computing, this is because predicting the mechanical behavior of such systems with hierarchical structures with multiple scales is very computationally demanding. Our main interest application concerns medium that has complex hierarchical morphology in the sense that features ranges from nanometer to millimeter scales. The goal of this work is to propose a computationally efficient numerical tool that can be used to perform everyday predictive simulations as an integral part of osteoporosis treatment, for example. To achieve that, highly heterogeneous media are considered that resembles trabecular bone tissues. The related fine-scale linear elasticity problem is of high contrast and high frequency. The finite element method (FEM) is applied for discretization of the related linear elasticity problem, using separable displacement decomposition. The new feature in this work is that at coarser levels, a block diagonal preconditioner is applied that incorporates an analytical effective tensor into the simulation, avoiding costly numerical solutions of local problems that are inherent in methods for multiscale problems. The robustness of the new proposed algorithm is measured by comparing the number of V-cycles necessary to resolve the considered multiscale problems with other well known techniques.

  8. Application of numerical methods to elasticity imaging.

    PubMed

    Castaneda, Benjamin; Ormachea, Juvenal; Rodríguez, Paul; Parker, Kevin J

    2013-03-01

    Elasticity imaging can be understood as the intersection of the study of biomechanical properties, imaging sciences, and physics. It was mainly motivated by the fact that pathological tissue presents an increased stiffness when compared to surrounding normal tissue. In the last two decades, research on elasticity imaging has been an international and interdisciplinary pursuit aiming to map the viscoelastic properties of tissue in order to provide clinically useful information. As a result, several modalities of elasticity imaging, mostly based on ultrasound but also on magnetic resonance imaging and optical coherence tomography, have been proposed and applied to a number of clinical applications: cancer diagnosis (prostate, breast, liver), hepatic cirrhosis, renal disease, thyroiditis, arterial plaque evaluation, wall stiffness in arteries, evaluation of thrombosis in veins, and many others. In this context, numerical methods are applied to solve forward and inverse problems implicit in the algorithms in order to estimate viscoelastic linear and nonlinear parameters, especially for quantitative elasticity imaging modalities. In this work, an introduction to elasticity imaging modalities is presented. The working principle of qualitative modalities (sonoelasticity, strain elastography, acoustic radiation force impulse) and quantitative modalities (Crawling Waves Sonoelastography, Spatially Modulated Ultrasound Radiation Force (SMURF), Supersonic Imaging) will be explained. Subsequently, the areas in which numerical methods can be applied to elasticity imaging are highlighted and discussed. Finally, we present a detailed example of applying total variation and AM-FM techniques to the estimation of elasticity.

  9. Elastic metamaterial beam with remotely tunable stiffness

    SciTech Connect

    Qian, Wei; Yu, Zhengyue; Wang, Xiaole; Lai, Yun; Yellen, Benjamin B.

    2016-02-07

    We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ∼30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

  10. Estimation of In vivo Cancellous Bone Elasticity

    NASA Astrophysics Data System (ADS)

    Otani, Takahiko; Mano, Isao; Tsujimoto, Toshiyuki; Yamamoto, Tadahito; Teshima, Ryota; Naka, Hiroshi

    2009-07-01

    The effect of decreasing bone density (a symptom of osteoporosis) is greater for cancellous bone than for dense cortical bone, because cancellous bone is metabolically more active. Therefore, the bone density or bone mineral density of cancellous bone is generally used to estimate the onset of osteoporosis. Elasticity or elastic constant is a fundamental mechanical parameter and is directly related to the mechanical strength of bone. Accordingly, elasticity is a preferable parameter for assessing fracture risk. A novel ultrasonic bone densitometer LD-100 has been developed to determine the mass density and elasticity of cancellous bone with a spatial resolution comparable to that of peripheral quantitative computed tomography. Bone density and bone elasticity are evaluated using ultrasonic parameters based on fast and slow waves in cancellous bone by modeling the ultrasonic wave propagation path. Elasticity is deduced from the measured bone density and the propagation speed of the fast wave. Thus, the elasticity of cancellous bone is approximately expressed by a cubic equation of bone density.

  11. Coupled elasticity in soft solid foams

    NASA Astrophysics Data System (ADS)

    Gorlier, F.; Khidas, Y.; Pitois, O.

    2017-09-01

    Elasticity of soft materials can be greatly influenced by the presence of air bubbles. Such a capillary effect is expected for a wide range of materials, from polymer gels to concentrated emulsions and colloidal suspensions. Whereas experimental results and theory exist for describing the elasto-capillary behavior of bubbly materials (i.e. with moderate gas volume fractions), foamy systems still require a dedicated study in order to increase our understanding of elasticity in aerated materials over the full range of gas volume fractions. Here we elaborate well-controlled foams with concentrated emulsion and we measure their shear elastic modulus as a function of gas fraction, bubble size and elastic modulus of the emulsion. Such complex foams possess the elastic features of both the bubble assembly and the interstitial matrix. Moreover, their elastic modulus is shown to be governed by two parameters, namely the gas volume fraction and the elasto-capillary number, defined as the ratio of the emulsion modulus with the bubble capillary pressure. We connect our results for foams with existing data for bubbly systems and we provide a general view for the effect of gas bubbles in soft elastic media. Finally, we suggest that our results could be useful for estimating the shear modulus of aqueous foams and emulsions with multimodal size distributions.

  12. Elastic metamaterial beam with remotely tunable stiffness

    NASA Astrophysics Data System (ADS)

    Qian, Wei; Yu, Zhengyue; Wang, Xiaole; Lai, Yun; Yellen, Benjamin B.

    2016-02-01

    We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ˜30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

  13. Intramuscular pressures beneath elastic and inelastic leggings

    NASA Technical Reports Server (NTRS)

    Murthy, G.; Ballard, R. E.; Breit, G. A.; Watenpaugh, D. E.; Hargens, A. R.

    1994-01-01

    Leg compression devices have been used extensively by patients to combat chronic venous insufficiency and by astronauts to counteract orthostatic intolerance following spaceflight. However, the effects of elastic and inelastic leggings on the calf muscle pump have not been compared. The purpose of this study was to compare in normal subjects the effects of elastic and inelastic compression on leg intramuscular pressure (IMP), an objective index of calf muscle pump function. IMP in soleus and tibialis anterior muscles was measured with transducer-tipped catheters. Surface compression between each legging and the skin was recorded with an air bladder. Subjects were studied under three conditions: (1) control (no legging), (2) elastic legging, and (3) inelastic legging. Pressure data were recorded for each condition during recumbency, sitting, standing, walking, and running. Elastic leggings applied significantly greater surface compression during recumbency (20 +/- 1 mm Hg, mean +/- SE) than inelastic leggings (13 +/- 2 mm Hg). During recumbency, elastic leggings produced significantly higher soleus IMP of 25 +/- 1 mm Hg and tibialis anterior IMP of 28 +/- 1 mm Hg compared to 17 +/- 1 mm Hg and 20 +/- 2 mm Hg, respectively, generated by inelastic leggings and 8 +/- 1 mm Hg and 11 +/- 1 mm Hg, respectively, without leggings. During sitting, walking, and running, however, peak IMPs generated in the muscular compartments by elastic and inelastic leggings were similar. Our results suggest that elastic leg compression applied over a long period in the recumbent posture may impede microcirculation and jeopardize tissue viability.(ABSTRACT TRUNCATED AT 250 WORDS).

  14. Hysteresis and nonlinear elasticity in rocks

    SciTech Connect

    McCall, K.R.; Guyer, R.A.

    1993-12-01

    The purpose of this paper is to describe a theory of the propagation of elastic waves in hysteretic nonlinear elastic materials, e.g., rock. In the next section, we introduce the Priesach-Mayergoyz (P-M) model [6,7] of hysteretic systems and adapt it to describe the hysteretic mesoscopic elastic units (HMEU) determining the elastic properties of a rock. We combine the P-M model with effective medium theory (EMT) [8] to find the elastic response of a rock that has experienced a specified pressure history. Next, we consider elastic wave propagation in a hysteretic nonlinear elastic system governed by a history dependent equation of state. We consider one-dimensional propagation of compressional waves. The equation of motion for the longitudinal displacement field contains the same hysteretic nonlinear interactions that characterize the equation of state. We solve the equation of motion using the Green function technique developed by McCall [9]. This solution lets us identify the qualitative features in harmonic generation that are signatures of nonlinearity and hysteresis.

  15. Effects of experimental income on demand for potentially real cigarettes.

    PubMed

    Koffarnus, Mikhail N; Wilson, Arlington George; Bickel, Warren K

    2015-03-01

    Cigarette demand, or the change in cigarette consumption as a function of price, is a measure of reinforcement that is associated with level of tobacco dependence and other clinically relevant measures, but the effects of experimentally controlled income on real-world cigarette consumption have not been examined. In this study, income available for cigarette purchases was manipulated to assess the effect on cigarette demand. Tobacco-dependent cigarette smokers (n = 15) who smoked 10-40 cigarettes per day completed a series of cigarette purchasing tasks under a variety of income conditions meant to mimic different weekly cigarette budgets: $280, approximately $127, $70, or approximately $32 per week. Prices of $0.12, $0.25, $0.50, and $1.00 per cigarette were assessed in each income condition. Participants were instructed to purchase as many cigarettes as they would like for the next week and to only consume cigarettes purchased in the context of the study. One price in 1 income condition was randomly chosen to be "real," and the cigarettes and the excess money in the budget for that condition were given to the participant. Results indicate that demand elasticity was negatively correlated with income. Demand intensity (consumption at low prices) was unrelated to income condition and remained high across incomes. These results indicate that the amount of income that is available for cigarette purchases has a large effect on cigarette consumption, but only at high prices. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Latent factor structure of a behavioral economic marijuana demand curve.

    PubMed

    Aston, Elizabeth R; Farris, Samantha G; MacKillop, James; Metrik, Jane

    2017-08-01

    Drug demand, or relative value, can be assessed via analysis of behavioral economic purchase task performance. Five demand indices are typically obtained from drug purchase tasks. The goal of this research was to determine whether metrics of marijuana reinforcement from a marijuana purchase task (MPT) exhibit a latent factor structure that efficiently characterizes marijuana demand. Participants were regular marijuana users (n = 99; 37.4% female, 71.5% marijuana use days [5 days/week], 15.2% cannabis dependent) who completed study assessments, including the MPT, during a baseline session. Principal component analysis was used to examine the latent structure underlying MPT indices. Concurrent validity was assessed via examination of relationships between latent factors and marijuana use, past quit attempts, and marijuana expectancies. A two-factor solution was confirmed as the best fitting structure, accounting for 88.5% of the overall variance. Factor 1 (65.8% variance) reflected "Persistence," indicating sensitivity to escalating marijuana price, which comprised four MPT indices (elasticity, O max, P max, and breakpoint). Factor 2 (22.7% variance) reflected "Amplitude," indicating the amount consumed at unrestricted price (intensity). Persistence factor scores were associated with fewer past marijuana quit attempts and lower expectancies of negative use outcomes. Amplitude factor scores were associated with more frequent use, dependence symptoms, craving severity, and positive marijuana outcome expectancies. Consistent with research on alcohol and cigarette purchase tasks, the MPT can be characterized with a latent two-factor structure. Thus, demand for marijuana appears to encompass distinct dimensions of price sensitivity and volumetric consumption, with differential relations to other aspects of marijuana motivation.

  17. Role of elasticity in stagnant lid convection

    NASA Astrophysics Data System (ADS)

    Patocka, Vojtech; Tackley, Paul; Cadek, Ondrej

    2016-04-01

    A present limitation of global thermo-chemical convection models is that they assume a purely viscous or visco-plastic flow law for solid rock, i.e. elasticity is ignored. This may not be a good assumption in the cold, outer boundary layer known as the lithosphere, where elastic deformation may be important. Elasticity in the lithosphere plays at least two roles: It changes surface topography, which changes the relationship between topography and gravity, and it alters the stress distribution in the lithosphere, which may affect dynamical behaviour such as the formation of plate boundaries and other tectonics features. In the present work we study these effects in the context of stagnant lid convection. We use StagYY (Tackley, 2008) enhanced to include elasticity through adding advected elastic stresses to the momentum equation and replacing viscosity by the "effective" one (the method described in e.g. Moresi et al., 2002). First, a test example with a cylinder rising below the lithosphere (Crameri et al., 2012) is considered in various geometries and the effect of elasticity on the resulting topography and geoid is evaluated. Both free-slip and free-surface upper boundary condition is considered. Second, comparison of stagnant lid convection models with and without elasticity is performed. It is shown that global characteristics of the convection do not change when a realistic value of shear modulus is employed and that the stress pattern in the lithosphere is very similar. The most important effect is that stresses build up gradually when elasticity is considered and thus the stress picture is more stable in the time domain in the elastic than in the viscous case. Viscoelastic lithosphere thus filters internal dynamics more effectively than a purely viscous one, responding only to features which stay stable for times comparable to its relaxation time. This effect is clearly recognizable only when free-surface upper boundary condition is considered. The role of

  18. Structural basis of spectrin elasticity

    SciTech Connect

    Shen, B.W.; Stevens, F.J.; Luthi, U.; Goldin, S.B.

    1991-10-17

    A new model of human erythrocyte {alpha}-spectrin is proposed. The secondary structure of human erythrocyte {alpha}-spectrin and its folding into a condensed structure that can convert reversibly in situ, into an elongated configuration is predicted from its deduced protein sequence. Results from conformational and amphipathicity analyses suggest that {alpha}-spectrin consists mainly of short amphipathicity helices interconnected by flexible turns and/or coils. The distribution of charges and amphipathicity of the helices can facilitate their folding into stable domains of 4 and 3 helices surrounding a hydrophobic core. The association between adjacent four- and three-helix domains further organize them into recurring seven-helix motifs that might constitute the basic structural units of the extended {alpha}-spectrin. The elongated spectrin molecule packs, in a sinusoidal fashion, through interactions between neighboring motifs into a compact structure. We suggest that the reversible extension and contraction of this sigmoidally packed structure is the molecular basis of the mechanism by which spectrin contributes to the elasticity of the red cell membrane.

  19. Elastic/Inelastic Measurement Project

    SciTech Connect

    Yates, Steven; Hicks, Sally; Vanhoy, Jeffrey; McEllistrem, Marcus

    2016-03-01

    The work scope involves the measurement of neutron scattering from natural sodium (23Na) and two isotopes of iron, 56Fe and 54Fe. Angular distributions, i.e., differential cross sections, of the scattered neutrons will be measured for 5 to 10 incident neutron energies per year. The work of the first year concentrates on 23Na, while the enriched iron samples are procured. Differential neutron scattering cross sections provide information to guide nuclear reaction model calculations in the low-­energy (few MeV) fast-­neutron region. This region lies just above the isolated resonance region, which in general is well studied; however, model calculations are difficult in this region because overlapping resonance structure is evident and direct nuclear reactions are becoming important. The standard optical model treatment exhibits good predictive ability for the wide-­region average cross sections but cannot treat the overlapping resonance features. In addition, models that do predict the direct reaction component must be guided by measurements to describe correctly the strength of the direct component, e.g., β2 must be known to describe the direct component of the scattering to the first excited state. Measurements of the elastic scattering differential cross sections guide the optical model calculations, while inelastic differential cross sections provide the crucial information for correctly describing the direct component. Activities occurring during the performance period are described.

  20. Demand Response Valuation Frameworks Paper

    SciTech Connect

    Heffner, Grayson

    2009-02-01

    While there is general agreement that demand response (DR) is a valued component in a utility resource plan, there is a lack of consensus regarding how to value DR. Establishing the value of DR is a prerequisite to determining how much and what types of DR should be implemented, to which customers DR should be targeted, and a key determinant that drives the development of economically viable DR consumer technology. Most approaches for quantifying the value of DR focus on changes in utility system revenue requirements based on resource plans with and without DR. This ''utility centric'' approach does not assign any value to DR impacts that lower energy and capacity prices, improve reliability, lower system and network operating costs, produce better air quality, and provide improved customer choice and control. Proper valuation of these benefits requires a different basis for monetization. The review concludes that no single methodology today adequately captures the wide range of benefits and value potentially attributed to DR. To provide a more comprehensive valuation approach, current methods such as the Standard Practice Method (SPM) will most likely have to be supplemented with one or more alternative benefit-valuation approaches. This report provides an updated perspective on the DR valuation framework. It includes an introduction and four chapters that address the key elements of demand response valuation, a comprehensive literature review, and specific research recommendations.

  1. Capillary stretching of elastic fibers

    NASA Astrophysics Data System (ADS)

    Protiere, Suzie; Stone, Howard A.; Duprat, Camille

    2014-11-01

    Fibrous media consisting of constrained flexible fibers can be found in many engineered systems (membranes in filters, woven textile, matted paper). When such materials interact with a liquid, the presence of liquid/air interfaces induces capillary forces that deform the fibers. To model this interaction we study the behaviour of a finite volume of liquid deposited on two parallel flexible fibers clamped at both ends. A tension along the fibers is imposed and may be varied. We show that the system undergoes various morphological changes as the interfiber distance, the elasticity and the tension of the fibers are varied. For a certain range of parameters, the liquid spreads along the fibers and pulls them together, leading to the ``zipping'' of the fibers. This capillary adhesion can then be enhanced or reduced by changing the tension within the fibers. We will show that balancing stretching and capillary forces allows the prediction of this transition as well as the conditions for which detachment of the fibers occurs. These results may be used to prevent the clogging of fibrous membranes or to optimize the capture of liquids.

  2. Elasticity and Binding of Adenovirus

    NASA Astrophysics Data System (ADS)

    Matthews, Garrett; Negishi, Atsuko; Seeger, Adam; McCarty, Doug; Taylor, Russell; Samulshi, Jude; Superfine, Richard

    1999-11-01

    Adenovirus was the first human virus found to cause the transformation of cells and is one of the more common vectors being used for the development of gene therapy. As such, much is known about the viral structure and genome; however, the events of the early infection cycle, such as binding of the virus to the cell membrane and the release of genetic material from the capsid, for this and other nonenveloped viruses, are not fully understood. With the atomic force microscope (AFM) we are able to image the virus in both air and liquids, allowing us to change the surrounding environment, varying such physiologically relevant parameters as osmolality or pH. We additionally have the ability to do manipulations on single virus particles in these environments using the nanoManipulator. The nanoManipulator is an advanced interface for AFM that allows real time three dimensional rendering of the topographical data, allows the sample surface to be non-destructively felt using a hand held stylus that responds to the information being sensed at the tip, and allows controlled modification of the surface. Using this tool we have translated single virions over various surfaces, allowing us to measure the adhesion between the capsid and these surfaces. Additionally, we are able to place the tip directly atop individual viruses and measure their elasticity under a compressive load being supplied by that tip. We can explore how this property changes as a function of the properties of the surrounding liquid.

  3. Elasticity of polymeric nanocolloidal particles

    PubMed Central

    Riest, Jonas; Athanasopoulou, Labrini; Egorov, Sergei A.; Likos, Christos N.; Ziherl, Primož

    2015-01-01

    Softness is an essential mechanical feature of macromolecular particles such as polymer-grafted nanocolloids, polyelectrolyte networks, cross-linked microgels as well as block copolymer and dendrimer micelles. Elasticity of individual particles directly controls their swelling, wetting, and adsorption behaviour, their aggregation and self-assembly as well as structural and rheological properties of suspensions. Here we use numerical simulations and self-consistent field theory to study the deformation behaviour of a single spherical polymer brush upon diametral compression. We observe a universal response, which is rationalised using scaling arguments and interpreted in terms of two coarse-grained models. At small and intermediate compressions the deformation can be accurately reproduced by modelling the brush as a liquid drop, whereas at large compressions the brush behaves as a soft ball. Applicable far beyond the pairwise-additive small-strain regime, the models may be used to describe microelasticity of nanocolloids in severe confinement including dense disordered and crystalline phases. PMID:26522242

  4. Demand Side Bidding. Final Report

    SciTech Connect

    Spahn, Andrew

    2003-12-31

    This document sets forth the final report for a financial assistance award for the National Association of Regulatory Utility Commissioners (NARUC) to enhance coordination between the building operators and power system operators in terms of demand-side responses to Location Based Marginal Pricing (LBMP). Potential benefits of this project include improved power system reliability, enhanced environmental quality, mitigation of high locational prices within congested areas, and the reduction of market barriers for demand-side market participants. NARUC, led by its Committee on Energy Resources and the Environment (ERE), actively works to promote the development and use of energy efficiency and clean distributive energy policies within the framework of a dynamic regulatory environment. Electric industry restructuring, energy shortages in California, and energy market transformation intensifies the need for reliable information and strategies regarding electric reliability policy and practice. NARUC promotes clean distributive generation and increased energy efficiency in the context of the energy sector restructuring process. NARUC, through ERE's Subcommittee on Energy Efficiency, strives to improve energy efficiency by creating working markets. Market transformation seeks opportunities where small amounts of investment can create sustainable markets for more efficient products, services, and design practices.

  5. Highly elastic conductive polymeric MEMS

    PubMed Central

    Ruhhammer, J; Zens, M; Goldschmidtboeing, F; Seifert, A; Woias, P

    2015-01-01

    Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations. PMID:27877753

  6. Highly elastic conductive polymeric MEMS

    NASA Astrophysics Data System (ADS)

    Ruhhammer, J.; Zens, M.; Goldschmidtboeing, F.; Seifert, A.; Woias, P.

    2015-02-01

    Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations.

  7. Failure of classical elasticity in auxetic foams

    NASA Astrophysics Data System (ADS)

    Roh, J. H.; Giller, C. B.; Mott, P. H.; Roland, C. M.

    2013-04-01

    Poisson's ratio, ν, was measured for four materials, a rubbery polymer, a conventional soft foam, and two auxetic foams. We find that for the first two materials, having ν ≥ 0.2, the experimental determinations of Poisson's ratio are in good agreement with values calculated from the shear and tensile moduli using the equations of classical elasticity. However, for the two auxetic materials (ν < 0), the equations of classical elasticity give values significantly different from the measured ν. We offer an interpretation of these results based on a recently published analysis of the bounds on Poisson's ratio for classical elasticity to be applicable.

  8. Deterministic Folding in Stiff Elastic Membranes

    NASA Astrophysics Data System (ADS)

    Tallinen, T.; Åström, J. A.; Timonen, J.

    2008-09-01

    Crumpled membranes have been found to be characterized by complex patterns of spatially seemingly random facets separated by narrow ridges of high elastic energy. We demonstrate by numerical simulations that compression of stiff elastic membranes with small randomness in their initial configurations leads to either random ridge configurations (high entropy) or nearly deterministic folds (low elastic energy). For folding with symmetric ridge configurations to appear in part of the crumpling processes, the crumpling rate must be slow enough. Folding stops when the thickness of the folded structure becomes important, and crumpling continues thereafter as a random process.

  9. Marangoni elasticity of flowing soap films

    NASA Astrophysics Data System (ADS)

    Kim, Ildoo; Mandre, Shreyas

    2017-08-01

    We measure the Marangoni elasticity of a flowing soap film to be 22 mN/m irrespective of its width, thickness, flow speed, or the bulk soap concentration. We perform this measurement by generating an oblique shock in the soap film and measuring the shock angle, flow speed, and thickness. We postulate that the elasticity is constant because the film surface is crowded with soap molecules. Our method allows nondestructive measurement of flowing soap film elasticity and the value 22 mN/m is likely applicable to other similarly constructed flowing soap films.

  10. Polycrystalline gamma plutonium's elastic moduli versus temperature

    SciTech Connect

    Migliori, Albert; Betts, J; Trugman, A; Mielke, C H; Mitchell, J N; Ramos, M; Stroe, I

    2009-01-01

    Resonant ultrasound spectroscopy was used to measure the elastic properties of pure polycrystalline {sup 239}Pu in the {gamma} phase. Shear and longitudinal elastic moduli were measured simultaneously and the bulk modulus was computed from them. A smooth, linear, and large decrease of all elastic moduli with increasing temperature was observed. They calculated the Poisson ratio and found that it increases from 0.242 at 519 K to 0.252 at 571 K. These measurements on extremely well characterized pure Pu are in agreement with other reported results where overlap occurs.

  11. Elastic properties of polycrystalline dense matter

    NASA Astrophysics Data System (ADS)

    Kobyakov, D.; Pethick, C. J.

    2015-04-01

    Elastic properties of the solid regions of neutron star crusts and white dwarfs play an important role in theories of stellar oscillations. Matter in compact stars is presumably polycrystalline and, since the elastic properties of single crystals of such matter are very anisotropic, it is necessary to relate elastic properties of the polycrystal to those of a single crystal. We calculate the effective shear modulus of polycrystalline matter with randomly oriented crystallites using a self-consistent theory that has been very successful in applications to terrestrial materials and show that previous calculations overestimate the shear modulus by approximately 28 per cent.

  12. Full Elasticity Tensor from Thermal Diffuse Scattering

    NASA Astrophysics Data System (ADS)

    Wehinger, Björn; Mirone, Alessandro; Krisch, Michael; Bosak, Alexeï

    2017-01-01

    We present a method for the precise determination of the full elasticity tensor from a single crystal diffraction experiment using monochromatic x rays. For the two benchmark systems calcite and magnesium oxide, we show that the measurement of thermal diffuse scattering in the proximity of Bragg reflections provides accurate values of the complete set of elastic constants. This approach allows for a reliable and model-free determination of the elastic properties and can be performed together with crystal structure investigation in the same experiment.

  13. Elastic unbalance of composite rim flywheels

    SciTech Connect

    Portnov, G.G.; Barinov, I.N.; Kulakov, V.L.

    1995-01-01

    Elastic unbalance of a composite flywheel is considered to be caused by different strain character of the rotating rim due to the distributed material density homogeneity or the corrective mass balancing it in the static state. An analysis has been carried out on the effect of elasticity of the rim flywheel on the linear elastic unbalance and its magnitude for an actual composite flywheel has been calculated. A procedure has been developed for the elimination of unbalance using two corrective masses. The problem of angular unbalance of a rim flywheel has also been considered. The finite element method has been used for computation.

  14. Quantum-elastic bump on a surface

    NASA Astrophysics Data System (ADS)

    Atanasov, Victor; Dandoloff, Rossen

    2017-01-01

    We use an exact solution of the elastic membrane shape equation, representing the curvature, which will serve as a quantum potential in the quantum mechanical two dimensional Schrödinger equation for a (quasi-) particle on the surface of the membrane. Surface curvature in the quasi one-dimensional case is related to an unexpected static formation: on one hand the elastic energy has a maximum where surface curvature has a maximum and on the other hand the concentration of the expectation value to find the (quasi-) particle is again where the elastic energy is concentrated, namely where surface curvature has a maximum. This represents a particular form of a conformon.

  15. The effects of next-day class characteristics on alcohol demand in college students.

    PubMed

    Berman, Hanna L; Martinetti, Margaret P

    2017-06-01

    Behavioral economic principles have been useful for addressing strategies to reduce alcohol consumption among college students. For example, academic variables (such as class schedule or academic rigor) have been found to affect alcohol demand assessed with a hypothetical alcohol purchase task (APT). The present studies used the APT to address the effects of 2 academic variables: next-day course level (no class, introductory level or upper level) and class size (no class, 30-student or 12-student). In each of 2 experiments, undergraduate participants read a description of a drinking context (either a no-class control version or 1 of the academic constraint conditions) and were asked to indicate how many drinks they would purchase at a variety of prices. Hursh and Silberberg's (2008) exponential demand equation was used to determine intensity and elasticity of demand, and Hursh and Roma's (2015) essential value (EV) parameter was calculated to assess essential value. In both experiments, a next-day class reduced alcohol demand, and alcohol consumption decreased as drink price increased. The presence of a smaller next-day class reduced alcohol demand compared with a larger next-day class; however, course level did not differentially affect alcohol demand. These results suggest that smaller next-day classes may reduce alcohol demand among college students and also provide initial evidence for the reliability of EV across studies. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. Prospects for European labour demand.

    PubMed

    Lindley, R M

    1988-07-01

    The impact of economic and technological trends upon the level and structure of labor demand is examined, exploring the methods used to model the labor market and making special reference to demography and technology. Evidence on recent and prospective changes in labor demand is reviewed for France, Germany, Italy, the Netherlands, and the UK. The models used to explore future employment scenarios usually fail to incorporate the linkages required to fully analyze the various demographic-economic interactions. Further, this is not generally viewed as a limitation, given the time frame of most employment projections and their preoccupation with changes in the structure of labor demand. Medium-term multisectoral models tend to pay more attention to both demographic and technical change, but the treatment of both aspects is limited. The projections provide a framework for considering how both socioeconomic behavior and policy might change to achieve different outcomes. The greater a model's behavioral content, as expressed in its relationships between different variables, the greater the insight obtainable from simulation exercises. The 1st half of the 1970s was characterized by a reduction in German employment, representing the severest of European reactions to the oil crisis. The 2nd half of the decade recorded rapid growth in Italy and the Netherlands. The 1980s started with marked declines in Germany and the UK. Overall, the net gains of the 1970s were lost in the recession following the 2nd oil crisis. In none of the 5 countries studied does any realistic prospect emerge of achieving full employment before 2000. The most optimistic outcome is that unemployment will decline only slowly, it at all. The growth of both new forms and areas of employment will not compensate sufficiently for the loss of jobs elsewhere and the growth of labor supply. The industrial sector will continue to experience change in favor of the service sector but at a slower rate than during

  17. Cut Electric Bills by Controlling Demand

    ERIC Educational Resources Information Center

    Grumman, David L.

    1974-01-01

    Electric bills can be reduced by lowering electric consumption and by controlling demand -- the amount of electricity used at a certain point in time. Gives tips to help reduce electric demand at peak power periods. (Author/DN)

  18. 7 CFR 981.21 - Trade demand.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.21 Trade demand. Trade demand means the quantity of almonds...

  19. 7 CFR 981.21 - Trade demand.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.21 Trade demand. Trade demand means the quantity of almonds...

  20. 7 CFR 981.21 - Trade demand.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.21 Trade demand. Trade demand means the quantity of almonds...

  1. 7 CFR 981.21 - Trade demand.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.21 Trade demand. Trade demand means the quantity of almonds...

  2. 7 CFR 981.21 - Trade demand.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.21 Trade demand. Trade demand means the quantity of almonds...

  3. Mechanics of finite cracks in dissimilar anisotropic elastic media considering interfacial elasticity

    DOE PAGES

    Juan, Pierre -Alexandre; Dingreville, Remi

    2016-10-31

    Interfacial crack fields and singularities in bimaterial interfaces (i.e., grain boundaries or dissimilar materials interfaces) are considered through a general formulation for two-dimensional (2-D) anisotropic elasticity while accounting for the interfacial structure by means of an interfacial elasticity paradigm. The interfacial elasticity formulation introduces boundary conditions that are effectively equivalent to those for a weakly bounded interface. This formalism considers the 2-D crack-tip elastic fields using complex variable techniques. While the consideration of the interfacial elasticity does not affect the order of the singularity, it modifies the oscillatory effects associated with problems involving interface cracks. Constructive or destructive “interferences” aremore » directly affected by the interface structure and its elastic response. Furthermore, this general formulation provides an insight on the physical significance and the obvious coupling between the interface structure and the associated mechanical fields in the vicinity of the crack tip.« less

  4. Mechanics of finite cracks in dissimilar anisotropic elastic media considering interfacial elasticity

    NASA Astrophysics Data System (ADS)

    Juan, Pierre-Alexandre; Dingreville, Rémi

    2017-02-01

    Interfacial crack fields and singularities in bimaterial interfaces (i.e., grain boundaries or dissimilar materials interfaces) are considered through a general formulation for two-dimensional (2-D) anisotropic elasticity while accounting for the interfacial structure by means of an interfacial elasticity paradigm. The interfacial elasticity formulation introduces boundary conditions that are effectively equivalent to those for a weakly bounded interface. This formalism considers the 2-D crack-tip elastic fields using complex variable techniques. While the consideration of the interfacial elasticity does not affect the order of the singularity, it modifies the oscillatory effects associated with problems involving interface cracks. Constructive or destructive "interferences" are directly affected by the interface structure and its elastic response. This general formulation provides an insight on the physical significance and the obvious coupling between the interface structure and the associated mechanical fields in the vicinity of the crack tip.

  5. Mechanics of finite cracks in dissimilar anisotropic elastic media considering interfacial elasticity

    SciTech Connect

    Juan, Pierre -Alexandre; Dingreville, Remi

    2016-10-31

    Interfacial crack fields and singularities in bimaterial interfaces (i.e., grain boundaries or dissimilar materials interfaces) are considered through a general formulation for two-dimensional (2-D) anisotropic elasticity while accounting for the interfacial structure by means of an interfacial elasticity paradigm. The interfacial elasticity formulation introduces boundary conditions that are effectively equivalent to those for a weakly bounded interface. This formalism considers the 2-D crack-tip elastic fields using complex variable techniques. While the consideration of the interfacial elasticity does not affect the order of the singularity, it modifies the oscillatory effects associated with problems involving interface cracks. Constructive or destructive “interferences” are directly affected by the interface structure and its elastic response. Furthermore, this general formulation provides an insight on the physical significance and the obvious coupling between the interface structure and the associated mechanical fields in the vicinity of the crack tip.

  6. Dislocation core radii near elastic stability limits

    NASA Astrophysics Data System (ADS)

    Sawyer, C. A.; Morris, J. W., Jr.; Chrzan, D. C.

    2013-04-01

    Recent studies of transition metal alloys with compositions that place them near their limits of elastic stability [e.g., near the body-centered-cubic (BCC) to hexagonal-close-packed (HCP) transition] suggest interesting behavior for the dislocation cores. Specifically, the dislocation core size is predicted to diverge as the stability limit is approached. Here a simple analysis rooted in elasticity theory and the computation of ideal strength is used to analyze this divergence. This analysis indicates that dislocation core radii should diverge as the elastic limits of stability are approached in the BCC, HCP, and face-centered-cubic (FCC) structures. Moreover, external stresses and dislocation-induced stresses also increase the core radii. Density functional theory based total-energy calculations are combined with anisotropic elasticity theory to compute numerical estimates of dislocation core radii.

  7. Measuring Moduli Of Elasticity At High Temperatures

    NASA Technical Reports Server (NTRS)

    Wolfenden, Alan

    1993-01-01

    Shorter, squatter specimens and higher frequencies used in ultrasonic measurement technique. Improved version of piezo-electric ultrasonic composite oscillator technique used to measure moduli of elasticity of solid materials at high temperatures.

  8. Aligner for Elastic Collisions of Dropped Balls.

    ERIC Educational Resources Information Center

    Mellen, Walter Roy

    1995-01-01

    Discusses an aligner that permits dropping a stack of any number of balls of different sizes, elasticities, hardnesses, or types to observe the rebound of the top ball. Experimental results allow a reasonable comparison with theory. (MVL)

  9. Dynamic response of visco-elastic plates

    NASA Astrophysics Data System (ADS)

    Kadıoǧlu, Fethi; Tekin, Gülçin

    2016-12-01

    In this study, a comprehensive analysis about the dynamic response characteristics of visco-elastic plates is given. To construct the functional in the Laplace-Carson domain for the analysis of visco-elastic plates based on the Kirchhoff hypothesis, functional analysis method is employed. By using this new energy functional in the Laplace-Carson domain, moment values that are important for engineers can be obtained directly with excellent accuracy and element equations can be written explicitly. Three-element model is considered for modelling the visco-elastic material behavior. The solutions obtained in the Laplace-Carson domain by utilizing mixed finite element formulation are transformed to the time domain using the Durbin's inverse Laplace transform technique. The proposed mixed finite element formulation is shown to be simple to implement and gives satisfactory results for dynamic response of visco-elastic plates.

  10. Elastic spheres can walk on water

    PubMed Central

    Belden, Jesse; Hurd, Randy C.; Jandron, Michael A.; Bower, Allan F.; Truscott, Tadd T.

    2016-01-01

    Incited by public fascination and engineering application, water-skipping of rigid stones and spheres has received considerable study. While these objects can be coaxed to ricochet, elastic spheres demonstrate superior water-skipping ability, but little is known about the effect of large material compliance on water impact physics. Here we show that upon water impact, very compliant spheres naturally assume a disk-like geometry and dynamic orientation that are favourable for water-skipping. Experiments and numerical modelling reveal that the initial spherical shape evolves as elastic waves propagate through the material. We find that the skipping dynamics are governed by the wave propagation speed and by the ratio of material shear modulus to hydrodynamic pressure. With these insights, we explain why softer spheres skip more easily than stiffer ones. Our results advance understanding of fluid-elastic body interaction during water impact, which could benefit inflatable craft modelling and, more playfully, design of elastic aquatic toys. PMID:26842860

  11. Statistical properties of a folded elastic rod

    NASA Astrophysics Data System (ADS)

    Bayart, Elsa; Deboeuf, Stéphanie; Boué, Laurent; Corson, Francis; Boudaoud, Arezki; Adda-Bedia, Mokhtar

    2010-03-01

    A large variety of elastic structures naturally seem to be confined into environments too small to accommodate them; the geometry of folded structures span a wide range of length-scales. The elastic properties of these confined systems are further constrained by self-avoidance as well as by the dimensionality of both structures and container. To mimic crumpled paper, we devised an experimental setup to study the packing of a dimensional elastic object in 2D geometries: an elastic rod is folded at the center of a circular Hele-Shaw cell by a centripetal force. The initial configuration of the rod and the acceleration of the rotating disk allow to span different final folded configurations while the final rotation speed controls the packing intensity. Using image analysis we measure geometrical and mechanical properties of the folded configurations, focusing on length, curvature and energy distributions.

  12. Energy demand and population changes

    SciTech Connect

    Allen, E.L.; Edmonds, J.A.

    1980-12-01

    Since World War II, US energy demand has grown more rapidly than population, so that per capita consumption of energy was about 60% higher in 1978 than in 1947. Population growth and the expansion of per capita real incomes have led to a greater use of energy. The aging of the US population is expected to increase per capita energy consumption, despite the increase in the proportion of persons over 65, who consume less energy than employed persons. The sharp decline in the population under 18 has led to an expansion in the relative proportion of population in the prime-labor-force age groups. Employed persons are heavy users of energy. The growth of the work force and GNP is largely attributable to the growing participation of females. Another important consequence of female employment is the growth in ownership of personal automobiles. A third factor pushing up labor-force growth is the steady influx of illegal aliens.

  13. Soft lithography: masters on demand.

    PubMed

    Abdelgawad, Mohamed; Watson, Michael W L; Young, Edmond W K; Mudrik, Jared M; Ungrin, Mark D; Wheeler, Aaron R

    2008-08-01

    We report an ultra-rapid prototyping technique for forming microchannel networks for lab-on-a-chip applications, called masters on-demand. Channels are produced by replica molding on masters formed by laser printing on flexible copper printed circuit board (PCB) substrates. Masters of various designs and dimensions can be individually or mass produced in less than 10 minutes. Using this technique, we have fabricated channels as narrow as 100 microm with heights ranging between 9 microm and 70 microm. Multi-depth channel fabrication is also reported, using a two-step printing process. The functionality of devices formed in this manner is verified by performing in-channel electrophoretic separations and culture and analysis of primary mammalian cells.

  14. Video on demand internal trial

    NASA Astrophysics Data System (ADS)

    Sell, Chris

    1993-02-01

    This NYNEX internal trial was designed to test a variety of technical concepts pertaining to a true video on demand system. A three building complex was selected for the trial using coaxial and fiber optic transport systems. The trial period was approximately six weeks long with a total of eighteen movies available twenty four hours a day. A fully automated system was designed at the NYNEX Science and Technology Laboratory that incorporated video equipment and laser disk players. This system is controlled by a pair of Sun Microsystems workstations communicating via a local area network. Valuable knowledge was gained in the area of jukebox design, control systems, and menuing. Fiber optic delivery systems were investigated along with coaxial systems. The user base for this trial consisted of NYNEX employees instead of residential customers. Although the user base was not ideal, we gained insight into how people interact with a fully automated system.

  15. Positional demands of professional rugby.

    PubMed

    Lindsay, Angus; Draper, Nick; Lewis, John; Gieseg, Steven P; Gill, Nicholas

    2015-01-01

    Rugby union is a physically intense intermittent sport coupled with high force collisions. Each position within a team has specific requirements which are typically based on speed, size and skill. The aim of this study was to investigate the contemporary demands of each position and whether they can explain changes in psychophysiological stress. Urine and saliva samples were collected before and after five selected Super 15 rugby games from 37 players. Total neopterin (NP), cortisol and immunoglobulin A were analysed by SCX-high performance liquid chromatography and enzyme linked immunosorbent assay. Global positioning system software provided distance data, while live video analysis provided impact data. All contemporary demands were analysed as events per minute of game time. Forwards were involved in more total impacts, tackles and rucks compared to backs (p < 0.001), while backs were involved in more ball carries and covered more total distance and distance at high speed per minute of game time (p < 0.01). Loose forwards, inside and outside backs covered significantly more distance at high speed (p < 0.01), while there was a negligible difference with number of impacts between the forward positions. There was also minimal difference between positions in the percentage change in NP, cortisol and sIgA. The results indicate distance covered and number of impacts per minute of game time is position-dependent whereas changes in psychophysiological stress are independent. This information can be used to adapt training and recovery interventions to better prepare each position based on the physical requirements of the game.

  16. Microstrain-level measurement of third-order elastic constants applying dynamic acousto-elastic testing

    NASA Astrophysics Data System (ADS)

    Renaud, Guillaume; Talmant, Maryline; Marrelec, Guillaume

    2016-10-01

    The nonlinear elasticity of solids at the microstrain level has been recently studied by applying dynamic acousto-elastic testing. It is the analog of conventional quasi-static acousto-elastic experiments but the strain-dependence (or stress-dependence) of ultrasonic wave-speed is measured with an applied strain ranging from 10-7 to 10-5 and produced by a stationary elastic wave. In conventional quasi-static acousto-elastic experiments, the strain is applied in a quasi-static manner; it exceeds 10-4 and can reach 10-2. In this work, we apply dynamic acousto-elastic testing to measure the third-order elastic constants of two isotropic materials: polymethyl methacrylate and dry Berea sandstone. The peak amplitude of the dynamic applied strain is 8 × 10-6. The method is shown to be particularly suitable for materials exhibiting large elastic nonlinearity like sandstones, since the measurement is performed in the domain of validity of the third-order hyperelastic model. In contrast, conventional quasi-static acousto-elastic experiments in such materials are often performed outside the domain of validity of the third-order hyperelastic model and the stress-dependence of the ultrasonic wave-speed must be extrapolated at zero stress, leading to approximate values of the third-order elastic constants. The uncertainty of the evaluation of the third-order elastic constants is assessed by repeating multiple times the measurements and with Monte-Carlo simulations. The obtained values of the Murnaghan third-order elastic constants are l = -73 GPa ± 9%, m = -34 GPa ± 9%, and n = -61 GPa ± 10% for polymethyl methacrylate, and l = -17 000 GPa ± 20%, m = -11 000 GPa ± 10%, and n = -30 000 GPa ± 20% for dry Berea sandstone.

  17. Positron interactions with water–total elastic, total inelastic, and elastic differential cross section measurements

    SciTech Connect

    Tattersall, Wade; Chiari, Luca; Machacek, J. R.; Anderson, Emma; Sullivan, James P.; White, Ron D.; Brunger, M. J.; Buckman, Stephen J.; Garcia, Gustavo; Blanco, Francisco

    2014-01-28

    Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.

  18. 7 CFR 987.11 - Trade demand.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Trade demand. 987.11 Section 987.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... RIVERSIDE COUNTY, CALIFORNIA Order Regulating Handling Definitions § 987.11 Trade demand. Trade demand...

  19. 7 CFR 987.11 - Trade demand.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Trade demand. 987.11 Section 987.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... RIVERSIDE COUNTY, CALIFORNIA Order Regulating Handling Definitions § 987.11 Trade demand. Trade demand...

  20. The Aggregate Demand Curve: A Reply.

    ERIC Educational Resources Information Center

    Hansen, Richard B.; And Others

    1987-01-01

    Responds to claims about the instructional value of the downward-sloping aggregate demand curve in teaching principles of macroeconomics. Examines the effects of interest-rates and the role of money on demand curves. Concludes by arguing against the use of downward-sloping aggregate demand curves in textbooks. (RKM)

  1. 7 CFR 3560.709 - Demand letter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Demand letter. 3560.709 Section 3560.709 Agriculture... DIRECT MULTI-FAMILY HOUSING LOANS AND GRANTS Unauthorized Assistance § 3560.709 Demand letter. (a) If a... repayment schedule, the Agency will send the borrower a demand letter specifying: (1) The amount of...

  2. 31 CFR 29.511 - Demand letters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Demand letters. 29.511 Section 29.511... Overpayments § 29.511 Demand letters. Except as provided in § 29.516(e), before starting collection action to recover an overpayment, the Benefits Administrator must send a demand letter that informs the debtor in...

  3. Elastic properties of FeSi

    SciTech Connect

    Petrova, A. E.; Krasnorussky, V. N.; Stishov, S. M.

    2010-09-15

    Measurements of the sound velocities in a single crystal of FeSi were performed in the temperature range 4-300 K. Elastic constants C{sub 11} and C{sub 44} deviate from a quasiharmonic behavior at high temperature; on the other hand, elastic constants C{sub 12} increases anomalously in the entire temperature range, indicating a change in the electron structure of this material.

  4. A NONLINEAR MESOSCOPIC ELASTIC CLASS OF MATERIALS

    SciTech Connect

    P. JOHNSON; R. GUYER; L. OSTROVSKY

    1999-09-01

    It is becoming clear that the elastic properties of rock are shared by numerous other materials (sand, soil, some ceramics, concrete, etc.). These materials have one or more of the following properties in common strong nonlinearity, hysteresis in stress-strain relation, slow dynamics and discrete memory. Primarily, it is the material's compliance, the mesoscopic linkages between the rigid components, that give these materials their unusual elastic properties.

  5. Ultrasonic Measurement Of Elastic Constants Of Composites

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Mal, Ajit K.

    1994-01-01

    Ultrasonic testing system yields data on elastic constants of matrix/fiber laminated composite material. Related to one described in "Ultrasonic System Measures Elastic Properties of Composites" (NPO-18729). Tests performed nondestructive, and involve access by ultrasonic probes to only one side of material specimen. In comparison with other available ultrasonic testing systems, this system relatively inexpensive, and based on testing technique that is simpler and rapidly yields more-accurate results.

  6. Positron-inert gas differential elastic scattering

    NASA Technical Reports Server (NTRS)

    Kauppila, W. E.; Smith, Steven J.; Kwan, C. K.; Stein, T. S.

    1990-01-01

    Measurements are being made in a crossed beam experiment of the relative elastic differential cross section (DCS) for 5 to 300 eV positrons scattering from inert gas atoms (He, Ne, Ar, Kr, and Xe) in the angular range from 30 to 134 deg. Results obtained at energies around the positronium (Ps) formation threshold provide evidence that Ps formation and possibly other inelastic channels have an effect on the elastic scattering channel.

  7. Dynamics of multibody systems with elastic parts

    NASA Astrophysics Data System (ADS)

    Bremer, H.

    It is necessary in many cases to consider the elasticities of multibody systems, for example in the calculations involving light and fast industrial robots. For such cases, the differential equation system of the equations of motion take into account the large, rigid body motions and the relatively superposed elastic deformations, which are small in comparison. Starting from a one-beam system, a recursive procedure for multibody systems is presented for determining the equations of motion.

  8. Pitfalls of femoral titanium elastic nailing.

    PubMed

    Salonen, A; Lahdes-Vasama, T; Mattila, V M; Välipakka, J; Pajulo, O

    2015-06-01

    Despite several potential complications of elastic intramedullary nailing, it is currently the treatment of choice for femoral diaphyseal fractures in school-aged children. This study aimed to critically evaluate the complications of titanium elastic nailing in pediatric femoral shaft fractures. This study evaluated patients with a diaphyseal femoral fracture treated with titanium elastic nailing (TEN) in Tampere University Hospital in Finland. The study group included 32 children with a mean age of 9 years during a 5-year period, from 1 January 2003 to 31 December 2007. Data were collected from medical records and x-rays. Mean follow-up time was 42 months. Of 32 patients, 9 (28%) reported a postoperative complication. Complications were associated with nail prominence in five (16%) patients and instability in four (12%) patients. In patients with nail prominence, the titanium elastic nailing-nail ends were unbent and 10-35 mm outside the cortex of the distal femur. The nail prominence caused pain and delayed knee mobilization until the nail was removed after a mean time of 4 months. In patients with fracture instability, the mean titanium elastic nailing-nail/medullary canal diameter ratio was 46% and periosteal callus formation was 5.4 mm at the first control. In those with stable fractures, the values were 66% and 9.2 mm, respectively. Based on this study, two types of pitfalls in a small volume center were found. Titanium elastic nail ends were left unbent and too long. We recommend palpating the nail ends to exclude nail prominence and to verify free movement of the knee after nail cutting and bending. Fracture instability was caused by inserting titanium elastic nailing-nails that were too narrow. To avoid this complication, careful preoperative planning to select the proper-size titanium elastic nailing-nails and intraoperative testing of fracture stability under continuous fluoroscopy after the operation is advised. © The Finnish Surgical Society 2014.

  9. Elastic form factors at higher CEBAF energies

    SciTech Connect

    Petratos, G.G.

    1994-04-01

    The prospects for elastic scattering from few body systems with higher beam energies at CEBAF is presented. The deuteron and{sup 3}He elastic structure functions A(Q{sup 2}) can be measured at sufficiently high momentum transfers to study the transition between the conventional meson-nucleon and the constituent quark-gluon descriptions. Possible improvements in the proton magnetic form factor data are also presented.

  10. Elastic energy of protein-DNA chimeras

    NASA Astrophysics Data System (ADS)

    Tseng, Chiao-Yu; Wang, Andrew; Zocchi, Giovanni; Rolih, Biljana; Levine, Alex J.

    2009-12-01

    We present experimental measurements of the equilibrium elastic energy of protein-DNA chimeras, for two different sets of attachment points of the DNA “molecular spring” on the surface of the protein. Combining these with measurements of the enzyme’s activity under stress and a mechanical model of the system, we determine how the elastic energy is partitioned between the DNA and the protein. The analysis shows that the protein is mechanically stiffer than the DNA spring.

  11. U.S. Demand for Tobacco Products in a System Framework.

    PubMed

    Zheng, Yuqing; Zhen, Chen; Dench, Daniel; Nonnemaker, James M

    2016-07-11

    This study estimated a system of demand for cigarettes, little cigars/cigarillos, large cigars, e-cigarettes, smokeless tobacco, and loose smoking tobacco using market-level scanner data for convenience stores. We found that the unconditional own-price elasticities for the six categories are -1.188, -1.428, -1.501, -2.054, -0.532, and -1.678, respectively. Several price substitute (e.g., cigarettes and e-cigarettes) and complement (e.g., cigarettes and smokeless tobacco) relationships were identified. Magazine and television advertising increased demand for e-cigarettes, and magazine advertising increased demand for smokeless tobacco and had spillover effects on demand for other tobacco products. We also reported the elasticities by U.S. census regions and market size. These results may have important policy implications, especially viewed in the context of the rise of electronic cigarettes and the potential for harm reduction if combustible tobacco users switch to non-combustible tobacco products. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Income Elasticity Literature Review | Science Inventory | US ...

    EPA Pesticide Factsheets

    Following advice from the SAB Council, when estimating the economic value of reductions in air pollution-related mortality and morbidity risk, EPA accounts for the effect of personal income on the willingness to pay to reduce the risk of adverse health outcomes. These income growth adjustment factors are calculated using a combination of income elasticity estimates and income growth projections, both of which have remained essentially unchanged since 1999. These income elasticity estimates vary according to the severity of illness. EPA recently received advice from the SAB regarding the range of income elasticities to apply as well as the research standards to use when selecting income elasticity estimates. Following this advice, EPA consulted with a contractor to update its income elasticity and income growth projections, and generate new income growth adjustment factors. The SAB would evaluate the income elasticity estimates identified in the EPA-provided literature review, determining the extent to which these estimates are appropriate to use in human health benefits assessments.

  13. Linear Lumbar Localized Lysis of Elastic Fibers

    PubMed Central

    Tschen, Jaime A.

    2013-01-01

    Background: The absence or loss of elastic fibers in the skin is referred to as dermal elastolysis. Purpose: This paper describes a woman with a distinctive clinical presentation of mid-dermal elastolysis characterized morphologically by multiple horizontal raised bands on the lower back. Methods: A 20-year-old Filipino woman presented with multiple asymptomatic, flesh-colored, raised, firm, linear, cord-like bands on the lumbar area of her back. There were neither similar lesions elsewhere nor a family member with this condition. Results: Microscopic examination of the raised band showed nearly complete absence of elastic fibers in the mid dermis. In contrast, a biopsy of symmetrically located normal-appearing skin showed a uniform distribution of elastic fibers throughout the dermis. Linear lumbar localized elastolysis is a descriptive designation that accurately reflects a correlation of the clinical and pathological changes of this condition. Conclusion: The clinical differential of raised horizontal cord-like bands on the lower back (without a family history of an inherited elastic fiber disorder, a prior history of trauma, or a significant change in weight or exercise habit) includes linear focal elastosis and linear lumbar localized elastolysis. Microscopic evaluation of a Verhoeff-van Gieson stained lesion specimen (which may be accompanied by a biopsy of normal-appearing skin for comparison) will readily differentiate these conditions. The former is usually characterized by increased elastic fibers, whereas the latter, as in this patient, shows a paucity or absence of elastic fibers in the mid dermis. PMID:23882313

  14. Elastic actuator for precise force control

    DOEpatents

    Pratt, G.A.; Williamson, M.M.

    1997-07-22

    The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section. 30 figs.

  15. Elastic actuator for precise force control

    DOEpatents

    Pratt, Gill A.; Williamson, Matthew M.

    1997-07-22

    The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section.

  16. Elastic modulus of cetacean auditory ossicles.

    PubMed

    Tubelli, Andrew A; Zosuls, Aleks; Ketten, Darlene R; Mountain, David C

    2014-05-01

    In order to model the hearing capabilities of marine mammals (cetaceans), it is necessary to understand the mechanical properties, such as elastic modulus, of the middle ear bones in these species. Biologically realistic models can be used to investigate the biomechanics of hearing in cetaceans, much of which is currently unknown. In the present study, the elastic moduli of the auditory ossicles (malleus, incus, and stapes) of eight species of cetacean, two baleen whales (mysticete) and six toothed whales (odontocete), were measured using nanoindentation. The two groups of mysticete ossicles overall had lower average elastic moduli (35.2 ± 13.3 GPa and 31.6 ± 6.5 GPa) than the groups of odontocete ossicles (53.3 ± 7.2 GPa to 62.3 ± 4.7 GPa). Interior bone generally had a higher modulus than cortical bone by up to 36%. The effects of freezing and formalin-fixation on elastic modulus were also investigated, although samples were few and no clear trend could be discerned. The high elastic modulus of the ossicles and the differences in the elastic moduli between mysticetes and odontocetes are likely specializations in the bone for underwater hearing. Copyright © 2014 Wiley Periodicals, Inc.

  17. Digital instability of a confined elastic meniscus.

    PubMed

    Biggins, John S; Saintyves, Baudouin; Wei, Zhiyan; Bouchaud, Elisabeth; Mahadevan, L

    2013-07-30

    Thin soft elastic layers serving as joints between relatively rigid bodies may function as sealants, thermal, electrical, or mechanical insulators, bearings, or adhesives. When such a joint is stressed, even though perfect adhesion is maintained, the exposed free meniscus in the thin elastic layer becomes unstable, leading to the formation of spatially periodic digits of air that invade the elastic layer, reminiscent of viscous fingering in a thin fluid layer. However, the elastic instability is reversible and rate-independent, disappearing when the joint is unstressed. We use theory, experiments, and numerical simulations to show that the transition to the digital state is sudden (first-order), the wavelength and amplitude of the fingers are proportional to the thickness of the elastic layer, and the required separation to trigger the instability is inversely proportional to the in-plane dimension of the layer. Our study reveals the energetic origin of this instability and has implications for the strength of polymeric adhesives; it also suggests a method for patterning thin films reversibly with any arrangement of localized fingers in a digital elastic memory, which we confirm experimentally.

  18. Color Preferences of Patients Receiving Elastic Ligatures

    PubMed Central

    Elekdag-Turk, Selma; Ozkalayci, Nurhat; Isci, Devrim; Turk, Tamer

    2010-01-01

    Objectives: To determine the color preferences for elastic ligatures among patients receiving fixed-appliance orthodontic therapy. Methods: Five hundred patients with metal brackets (336 female patients and 164 male patients) were included, and their color preferences for elastic ligatures were recorded using a color scale. Chi-square analysis was performed to evaluate the color preferences and to determine the influence of age and gender on color preferences (P<.05). Results: Two hundred and seventy-six patients (55.2%) preferred strikingly colorful elastic ligatures, while 224 patients (44.8%) preferred less noticeable elastic ligatures. No significant difference was observed between the color preferences of female and male patients (P>.05). However, significant differences were observed between the color preferences of adolescents and older patients (P<.001). Conclusions: Female patients preferred red–purple-colored tones, while male patients preferred blue–black-colored tones. Adolescents preferred colorful elastic ligatures, while older patients preferred ligatures with less-noticeable colors. A stock of 10–12 colorful and less-noticeable elastic ligatures seems to be adequate to ensure patient satisfaction. PMID:20396449

  19. Income Elasticity Literature Review | Science Inventory | US ...

    EPA Pesticide Factsheets

    Following advice from the SAB Council, when estimating the economic value of reductions in air pollution-related mortality and morbidity risk, EPA accounts for the effect of personal income on the willingness to pay to reduce the risk of adverse health outcomes. These income growth adjustment factors are calculated using a combination of income elasticity estimates and income growth projections, both of which have remained essentially unchanged since 1999. These income elasticity estimates vary according to the severity of illness. EPA recently received advice from the SAB regarding the range of income elasticities to apply as well as the research standards to use when selecting income elasticity estimates. Following this advice, EPA consulted with a contractor to update its income elasticity and income growth projections, and generate new income growth adjustment factors. The SAB would evaluate the income elasticity estimates identified in the EPA-provided literature review, determining the extent to which these estimates are appropriate to use in human health benefits assessments.

  20. The Demand for Cigarettes in Tanzania and Implications for Tobacco Taxation Policy

    PubMed Central

    Kidane, Asmerom; Mduma, John; Naho, Alexis; Ngeh, Ernest Tingum; Hu, Teh-wei

    2016-01-01

    The study attempts to estimate the demand for cigarettes in Tanzania and presents simulation results on the effect of the cigarette excise tax on smoking participation, government revenue, and related topics. After briefly summarizing the magnitude and spread of cigarette consumption in the country, the paper reviews some empirical estimates from African and other countries. The 2008 Tanzanian household budget survey was used to estimate the demand for cigarettes in Tanzania. The descriptive statistics suggest that the smoking prevalence for Tanzania is 15.35 percent with low variability across expenditure (income) groups. Smoking intensity and per capita consumption were estimated at 7.08 cigarettes and 1.33 cigarettes, respectively, a relatively low value. A two-part demand equation model was used to estimate various elasticities. For the overall equation, the price elasticities of smoking participation, smoking intensity, and total elasticity were estimated at −0.879, −0.853, and −1.732, respectively. Compared to similar results in other developing countries, the estimates appear quite high. When estimated by expenditure (income) groups, the magnitude of the elasticity appears higher among high expenditure groups than among low expenditure groups. Two simulation exercises were undertaken. First, the effect of different excise rates on smoking participation rate, cigarette consumption, tax revenue, and related responses was estimated and highlighted. Second, the same exercise was undertaken to determine the effect of a given increase in the cigarette excise tax on various expenditure groups. The overall results suggest that an increase in the excise tax on cigarettes in Tanzania would reduce cigarette consumption and increase government tax revenue. PMID:27358905

  1. The Demand for Cigarettes in Tanzania and Implications for Tobacco Taxation Policy.

    PubMed

    Kidane, Asmerom; Mduma, John; Naho, Alexis; Ngeh, Ernest Tingum; Hu, Teh-Wei

    2015-10-01

    The study attempts to estimate the demand for cigarettes in Tanzania and presents simulation results on the effect of the cigarette excise tax on smoking participation, government revenue, and related topics. After briefly summarizing the magnitude and spread of cigarette consumption in the country, the paper reviews some empirical estimates from African and other countries. The 2008 Tanzanian household budget survey was used to estimate the demand for cigarettes in Tanzania. The descriptive statistics suggest that the smoking prevalence for Tanzania is 15.35 percent with low variability across expenditure (income) groups. Smoking intensity and per capita consumption were estimated at 7.08 cigarettes and 1.33 cigarettes, respectively, a relatively low value. A two-part demand equation model was used to estimate various elasticities. For the overall equation, the price elasticities of smoking participation, smoking intensity, and total elasticity were estimated at -0.879, -0.853, and -1.732, respectively. Compared to similar results in other developing countries, the estimates appear quite high. When estimated by expenditure (income) groups, the magnitude of the elasticity appears higher among high expenditure groups than among low expenditure groups. Two simulation exercises were undertaken. First, the effect of different excise rates on smoking participation rate, cigarette consumption, tax revenue, and related responses was estimated and highlighted. Second, the same exercise was undertaken to determine the effect of a given increase in the cigarette excise tax on various expenditure groups. The overall results suggest that an increase in the excise tax on cigarettes in Tanzania would reduce cigarette consumption and increase government tax revenue.

  2. Role of Higher-Order Elastic Moduli in Large Elastic Finite Deformation

    NASA Astrophysics Data System (ADS)

    Suzuki, Tetsuro; Osuka, Ken'ichi

    1993-05-01

    It is proposed here that the change in free energy of crystals associated with large elastic finite deformation can be estimated using higher-order elastic moduli up to a limited order. Numerical estimation of the change in free energy is performed for two examples of finite elastic deformation, with use of the data for higher-order elastic moduli of β-brass obtained by Swartz. One example is Bain deformation, which converts a bcc lattice into an fcc lattice or vice versa. The other is shear deformation along the (100) atomic plane.

  3. Far-field subwavelength imaging for ultrasonic elastic waves in a plate using an elastic hyperlens

    NASA Astrophysics Data System (ADS)

    Lee, Hyung Jin; Kim, Hoe Woong; Kim, Yoon Young

    2011-06-01

    Subwavelength imaging was experimentally performed for ultrasonic elastic waves by using an angularly stratified plat, an elastic plate hyperlens. It consists of alternating layers of aluminum and air, exhibiting a large contrast in elastic stiffness. A specially configured experimental setup is used to locate two sources within half the wavelength at 100 kHz. To explain the observed phenomenon, the homogenization of the elasticity coefficients of the stratified structure is employed. Because of the strong cylindrical anisotropy, an equifrequency contour becomes nearly flat along the angular wave vector so that evanescent waves involved with high angular resolution are converted to propagating waves.

  4. EDITORIAL: Photonic materials on demand Photonic materials on demand

    NASA Astrophysics Data System (ADS)

    Zheludev, Nikolay; Padilla, Willie J.; Brener, Igal

    2012-11-01

    As David Payne famously said, 'we never have a photonic material that we want...'. This has changed with the proliferation of nanotechnology. Metamaterials—artificial media structured on a sub-wavelength scale—offer a radical paradigm for the engineering of optical properties. Some remarkable advances have been possible with metamaterials. These include, for instance, negative-index media that refract light in the opposite direction from that of conventional materials, chiral materials that rotate the polarization state of light hundreds of thousands of times more strongly than natural optical crystals, and structured thin films with remarkably strong dispersion that can slow light in much the same way as resonant atomic systems with electromagnetically induced transparency. The research agenda is now shifting towards achieving tunable and switchable functionalities with metamaterials [1] where the goal is, paraphrasing Dave Payne, 'to have on demand the photonic material that we want'. The papers in this Journal of Optics special issue explore and review the different approaches to both switching and tuning of metamaterial properties through exploiting effects such as phase conjugation, intense photo-excitation and photoconductivity, the use of electro-optical effects in conductive oxides, the exploitation global quantum coherency and resonantly coupled classical resonator and quantum structures, hybridization with gain media and the manipulation with shapes and constitution of the complex metamolecules and metamaterial reliefs by design, or using MEMS actuation. References [1] Zheludev N I and Kivshar Y 2012 From metamaterials to metadevices Nature Mater.11 917

  5. Essays on economic development, energy demand, and the environment

    NASA Astrophysics Data System (ADS)

    Medlock, Kenneth Barry, III

    2000-10-01

    The rapid expansion of industry at the outset of economic development and the subsequent growth of the transportation and residential and commercial sectors dictate both the rate at which energy demand increases and the composition of primary fuel sources used to meet secondary requirements. Each of these factors each has an impact on the pollution problems that nations may face. Growth in consumer wealth, however, appears to eventually lead to a shift in priorities. In particular, the importance of the environment begins to take precedent over the acquisition of goods. Accordingly, cleaner energy alternatives are sought out. The approach taken here is to determine the energy profile of an average nation, and apply those results to a model of economic growth. Dematerialization of production and saturation of consumer bundles results in declining rates of growth of energy demand in broadly defined end-use sectors. The effects of technological change in fossil fuel efficiency, fossil fuel recovery, and 'backstop' energy resources on economic growth and the emissions of carbon dioxide are then analyzed. A central planner is assumed to optimize the consumption of goods and services subject to capital and resource constraints. Slight perturbations in the parameters are used to determine their local elasticities with respect to different endogenous variables, and give an indication of the effects of changes in the various assumptions.

  6. Demand for private health insurance in Chinese urban areas.

    PubMed

    Ying, Xiao-Hua; Hu, Teh-Wei; Ren, Jane; Chen, Wen; Xu, Ke; Huang, Jin-Hui

    2007-10-01

    Between 1993 and 2003, the proportion of urban residents without health insurance rose from 27 to 50%. The probability of outpatient visits in the previous 2 weeks dropped from 19.9 to 11.8% in urban areas between 1993 and 2003, and from 16.0 to 13.9% in rural areas. To improve risk-pooling and risk-sharing, private health insurance should play an important role in China's health insurance system. This paper estimates the demand for private health insurance in urban areas using contingent valuation methods. Individuals were asked about their willingness-to-pay (WTP) for major catastrophic disease insurance (MCDI), inpatient expenses insurance (IEI), and outpatient expenses insurance (OEI). The study was based on a household survey conducted in four small cities in China in 2004 and included 2671 respondents. More people would like to buy IEI and MCDI (48.5 and 43.0%, respectively) than OEI (24.5%). In addition, individuals would pay a higher premium for MCDI and IEI than for OEI. The price elasticities of demand for MCDI, IEI, and OEI were -0.27, -0.34, and -0.42, respectively. The determinants of enrollment in the three private health insurance programs were similar with employment status, age, education, and income.

  7. Demand for waste as fuel in the swedish district heating sector: a production function approach.

    PubMed

    Furtenback, Orjan

    2009-01-01

    This paper evaluates inter-fuel substitution in the Swedish district heating industry by analyzing almost all the district heating plants in Sweden in the period 1989-2003, specifically those plants incinerating waste. A multi-output plant-specific production function is estimated using panel data methods. A procedure for weighting the elasticities of factor demand to produce a single matrix for the whole industry is introduced. The price of waste is assumed to increase in response to the energy and CO2 tax on waste-to-energy incineration that was introduced in Sweden on 1 July 2006. Analysis of the plants involved in waste incineration indicates that an increase in the net price of waste by 10% is likely to reduce the demand for waste by 4.2%, and increase the demand for bio-fuels, fossil fuels, other fuels and electricity by 5.5%, 6.0%, 6.0% and 6.0%, respectively.

  8. Demand for private health insurance: how important is the quality gap?

    PubMed

    Costa, Joan; García, Jaume

    2003-07-01

    Perceived quality of private and public health care, income and insurance premium are among the determinants of demand for private health insurance (PHI). In the context of a model in which individuals are expected utility maximizers, the non purchasing choice can result in consuming either public health care or private health care with full cost paid out-of-pocket. This paper empirically analyses the effect of the determinants of the demand for PHI on the probability of purchasing PHI by estimating a pseudo-structural model to deal with missing data and endogeneity issues. Our findings support the hypothesis that the demand for PHI is indeed driven by the quality gap between private and public health care. As expected, PHI is a normal good and a rise in the insurance premium reduces the probability of purchasing PHI albeit displaying price elasticities smaller than one in absolute value for different groups of individuals. Copyright 2002 John Wiley & Sons, Ltd.

  9. Transversely Isotropic Elasticity Imaging of Cancellous Bone

    PubMed Central

    Shore, Spencer W.; Barbone, Paul E.; Oberai, Assad A.; Morgan, Elise F.

    2012-01-01

    To measure spatial variations in mechanical properties of biological materials, prior studies have typically performed mechanical tests on excised specimens of tissue. Less invasive measurements, however, are preferable in many applications, such as patient-specific modeling, disease diagnosis, and tracking of age- or damage-related degradation of mechanical properties. Elasticity imaging (elastography) is a nondestructive imaging method in which the distribution of elastic properties throughout a specimen can be reconstructed from measured strain or displacement fields. To date, most work in elasticity imaging has concerned incompressible, isotropic materials. This study presents an extension of elasticity imaging to three-dimensional, compressible, transversely isotropic materials. The formulation and solution of an inverse problem for an anisotropic tissue subjected to a combination of quasi-static loads is described, and an optimization and regularization strategy that indirectly obtains the solution to the inverse problem is presented. Several applications of transversely isotropic elasticity imaging to cancellous bone from the human vertebra are then considered. The feasibility of using isotropic elasticity imaging to obtain meaningful reconstructions of the distribution of material properties for vertebral cancellous bone from experiment is established. However, using simulation, it is shown that an isotropic reconstruction is not appropriate for anisotropic materials. It is further shown that the transversely isotropic method identifies a solution that predicts the measured displacements, reveals regions of low stiffness, and recovers all five elastic parameters with approximately 10% error. The recovery of a given elastic parameter is found to require the presence of its corresponding strain (e.g., a deformation that generates ε12 is necessary to reconstruct C1212), and the application of regularization is shown to improve accuracy. Finally, the effects

  10. Transversely isotropic elasticity imaging of cancellous bone.

    PubMed

    Shore, Spencer W; Barbone, Paul E; Oberai, Assad A; Morgan, Elise F

    2011-06-01

    To measure spatial variations in mechanical properties of biological materials, prior studies have typically performed mechanical tests on excised specimens of tissue. Less invasive measurements, however, are preferable in many applications, such as patient-specific modeling, disease diagnosis, and tracking of age- or damage-related degradation of mechanical properties. Elasticity imaging (elastography) is a nondestructive imaging method in which the distribution of elastic properties throughout a specimen can be reconstructed from measured strain or displacement fields. To date, most work in elasticity imaging has concerned incompressible, isotropic materials. This study presents an extension of elasticity imaging to three-dimensional, compressible, transversely isotropic materials. The formulation and solution of an inverse problem for an anisotropic tissue subjected to a combination of quasi-static loads is described, and an optimization and regularization strategy that indirectly obtains the solution to the inverse problem is presented. Several applications of transversely isotropic elasticity imaging to cancellous bone from the human vertebra are then considered. The feasibility of using isotropic elasticity imaging to obtain meaningful reconstructions of the distribution of material properties for vertebral cancellous bone from experiment is established. However, using simulation, it is shown that an isotropic reconstruction is not appropriate for anisotropic materials. It is further shown that the transversely isotropic method identifies a solution that predicts the measured displacements, reveals regions of low stiffness, and recovers all five elastic parameters with approximately 10% error. The recovery of a given elastic parameter is found to require the presence of its corresponding strain (e.g., a deformation that generates ɛ₁₂ is necessary to reconstruct C₁₂₁₂), and the application of regularization is shown to improve accuracy. Finally

  11. Demands of immigration among Chinese immigrant nurses.

    PubMed

    Ma, Amy X; Griffin, Mary T Quinn; Capitulo, Katie L; Fitzpatrick, Joyce J

    2010-10-01

    The purpose of this study was to identify the demands of immigration among Chinese nurses that have immigrated to the USA. The relationship between the demands of immigration and length of stay in the USA was investigated also. A descriptive correlational study design was used. A convenience sample of 128 nurses was recruited. A self-administered survey was conducted using the demands of immigration scale developed by Aroian, along with a demographic questionnaire. The results showed Chinese immigrant nurses have high demands of immigration. There were significant negative relationships between the demands of immigration and length of stay in the USA. Immigration demands decreased as length of stay increased but remained high even for those who had been in the USA for > 5 years. This information is vital to health-care agencies designing and implementing adaptation programmes targeting these demands to facilitate Chinese nurses' adaptation process.

  12. Elastic Properties of Sedimentary Rocks

    NASA Astrophysics Data System (ADS)

    Melendez Martinez, Jaime

    Sedimentary rocks are an important research topic since such rocks are associated to sources of ground water as well as oil, gas, and mineral reservoirs. In this work, elastic and physical properties of a variety of sedimentary samples that include glacial sediments, carbonates, shales, one evaporite, and one argillite from a variety of locations are investigated. Assuming vertical transverse isotropy, ultrasonic compressional- and shear-waves (at 1 MHz central frequency) were measured as a function of confining pressure on all samples with the exception of glacial samples which were tested assuming isotropy. Tensile strength tests (Brazilian test) were also carried out on selected glacial samples and, in addition, static-train measurements were conducted on shales and argillite samples. Lithological and textural features of samples were obtained through thin section techniques, scanning electron microscopy images and micro-tomography images. X-ray diffraction and X-Ray fluorescence provided the mineralogical oxides content information. Porosity, density, and pore structure were studied by using a mercury intrusion porosimeter and a helium pycnometer. The wide range of porosities of the studied samples (ranging from a minimum of 1% for shales to a maximum 45% for some glacial sediments) influence the measured velocities since high porosity sample shows an noticeable velocity increment as confining pressure increases as a consequence of closure of microcracks and pores, unlike low porosity samples where increment is quasi-lineal. Implementation of Gassmann's relation to ultrasonic velocities obtained from glacial samples has negligible impact on them when assuming water saturated samples, which suggests that state of saturation it is no so important in defining such velocities and instead they are mainly frame-controlled. On the other hand, velocities measured on carbonate and evaporite samples show that samples are at best weak anisotropic, thus the intrinsic

  13. Factor demand in Swedish manufacturing industry with special reference to the demand for energy. Instantaneous adjustment models; some results

    NASA Astrophysics Data System (ADS)

    Sjoeholm, K. R.

    1981-02-01

    The dual approach to the theory of production is used to estimate factor demand functions of the Swedish manufacturing industry. Two approximations of the cost function, the translog and the generalized Leontief models, are used. The price elasticities of the factor demand do not seem to depend on the choice of model. This is at least true as to the sign pattern and as to the inputs capital, labor, total energy and other materials. Total energy is separated into solid fuels, gasoline, fuel oil, electricity and a residual. Fuel oil and electricity are found to be substitutes by both models. Capital and energy are shown to be substitutes. This implies that Swedish industry will save more energy if the capital cost can be reduced. Both models are, in the best versions, able to detect an inappropriate variable. The assumption of perfect competition on the product market, is shown to be inadequate by both models. When this assumption is relaxed, the normal substitution pattern among the inputs is resumed.

  14. Comparing exponential and exponentiated models of drug demand in cocaine users.

    PubMed

    Strickland, Justin C; Lile, Joshua A; Rush, Craig R; Stoops, William W

    2016-12-01

    Drug purchase tasks provide rapid and efficient measurement of drug demand. Zero values (i.e., prices with zero consumption) present a quantitative challenge when using exponential demand models that exponentiated models may resolve. We aimed to replicate and advance the utility of using an exponentiated model by demonstrating construct validity (i.e., association with real-world drug use) and generalizability across drug commodities. Participants (N = 40 cocaine-using adults) completed Cocaine, Alcohol, and Cigarette Purchase Tasks evaluating hypothetical consumption across changes in price. Exponentiated and exponential models were fit to these data using different treatments of zero consumption values, including retaining zeros or replacing them with 0.1, 0.01, or 0.001. Excellent model fits were observed with the exponentiated model. Means and precision fluctuated with different replacement values when using the exponential model but were consistent for the exponentiated model. The exponentiated model provided the strongest correlation between derived demand intensity (Q0) and self-reported free consumption in all instances (Cocaine r = .88; Alcohol r = .97; Cigarette r = .91). Cocaine demand elasticity was positively correlated with alcohol and cigarette elasticity. Exponentiated parameters were associated with real-world drug use (e.g., weekly cocaine use) whereas these correlations were less consistent for exponential parameters. Our findings show that selection of zero replacement values affects demand parameters and their association with drug-use outcomes when using the exponential model but not the exponentiated model. This work supports the adoption of the exponentiated demand model by replicating improved fit and consistency and demonstrating construct validity and generalizability. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  15. A Stated Preference Investigation into the Chinese Demand for Farmed vs. Wild Bear Bile

    PubMed Central

    Dutton, Adam J.; Hepburn, Cameron; Macdonald, David W.

    2011-01-01

    Farming of animals and plants has recently been considered not merely as a more efficient and plentiful supply of their products but also as a means of protecting wild populations from that trade. Amongst these nascent farming products might be listed bear bile. Bear bile has been exploited by traditional Chinese medicinalists for millennia. Since the 1980s consumers have had the options of: illegal wild gall bladders, bile extracted from caged live bears or the acid synthesised chemically. Despite these alternatives bears continue to be harvested from the wild. In this paper we use stated preference techniques using a random sample of the Chinese population to estimate demand functions for wild bear bile with and without competition from farmed bear bile. We find a willingness to pay considerably more for wild bear bile than farmed. Wild bear bile has low own price elasticity and cross price elasticity with farmed bear bile. The ability of farmed bear bile to reduce demand for wild bear bile is at best limited and, at prevailing prices, may be close to zero or have the opposite effect. The demand functions estimated suggest that the own price elasticity of wild bear bile is lower when competing with farmed bear bile than when it is the only option available. This means that the incumbent product may actually sell more items at a higher price when competing than when alone in the market. This finding may be of broader interest to behavioural economists as we argue that one explanation may be that as product choice increases price has less impact on decision making. For the wildlife farming debate this indicates that at some prices the introduction of farmed competition might increase the demand for the wild product. PMID:21799733

  16. The impact of price and tobacco control policies on the demand for electronic nicotine delivery systems

    PubMed Central

    Huang, Jidong; Tauras, John; Chaloupka, Frank J

    2014-01-01

    Background While much is known about the demand for conventional cigarettes, little is known about the determinants of demand for electronic nicotine delivery systems (ENDS or e-cigarettes). The goal of this study is to estimate the own and cross-price elasticity of demand for e-cigarettes and to examine the impact of cigarette prices and smoke-free policies on e-cigarette sales. Methods Quarterly e-cigarette prices and sales and conventional cigarette prices from 2009 to 2012 were constructed from commercial retail store scanner data from 52 US markets, for food, drug and mass stores, and from 25 markets, for convenience stores. Fixed-effects models were used to estimate the own and cross-price elasticity of demand for e-cigarettes and associations between e-cigarette sales and cigarette prices and smoke-free policies. Results Estimated own price elasticities for disposable e-cigarettes centred around −1.2, while those for reusable e-cigarettes were approximately −1.9. Disposable e-cigarette sales were higher in markets where reusable e-cigarette prices were higher and where less of the population was covered by a comprehensive smoke-free policy. There were no consistent and statistically significant relationships between cigarette prices and e-cigarette sales. Conclusions E-cigarette sales are very responsive to own price changes. Disposable e-cigarettes appear to be substitutes for reusable e-cigarettes. Policies increasing e-cigarette retail prices, such as limiting rebates, discounts and coupons and imposing a tax on e-cigarettes, could potentially lead to significant reductions in e-cigarette sales. Differential tax policies based on product type could lead to substitution between different types of e-cigarettes. PMID:24935898

  17. The impact of price and tobacco control policies on the demand for electronic nicotine delivery systems.

    PubMed

    Huang, Jidong; Tauras, John; Chaloupka, Frank J

    2014-07-01

    While much is known about the demand for conventional cigarettes, little is known about the determinants of demand for electronic nicotine delivery systems (ENDS or e-cigarettes). The goal of this study is to estimate the own and cross-price elasticity of demand for e-cigarettes and to examine the impact of cigarette prices and smoke-free policies on e-cigarette sales. Quarterly e-cigarette prices and sales and conventional cigarette prices from 2009 to 2012 were constructed from commercial retail store scanner data from 52 U.S. markets, for food, drug and mass stores, and from 25 markets, for convenience stores. Fixed-effects models were used to estimate the own and cross-price elasticity of demand for e-cigarettes and associations between e-cigarette sales and cigarette prices and smoke-free policies. Estimated own price elasticities for disposable e-cigarettes centred around -1.2, while those for reusable e-cigarettes were approximately -1.9. Disposable e-cigarette sales were higher in markets where reusable e-cigarette prices were higher and where less of the population was covered by a comprehensive smoke-free policy. There were no consistent and statistically significant relationships between cigarette prices and e-cigarette sales. E-cigarette sales are very responsive to own price changes. Disposable e-cigarettes appear to be substitutes for reusable e-cigarettes. Policies increasing e-cigarette retail prices, such as limiting rebates, discounts and coupons and imposing a tax on e-cigarettes, could potentially lead to significant reductions in e-cigarette sales. Differential tax policies based on product type could lead to substitution between different types of e-cigarettes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. A stated preference investigation into the Chinese demand for farmed vs. wild bear bile.

    PubMed

    Dutton, Adam J; Hepburn, Cameron; Macdonald, David W

    2011-01-01

    Farming of animals and plants has recently been considered not merely as a more efficient and plentiful supply of their products but also as a means of protecting wild populations from that trade. Amongst these nascent farming products might be listed bear bile. Bear bile has been exploited by traditional Chinese medicinalists for millennia. Since the 1980s consumers have had the options of: illegal wild gall bladders, bile extracted from caged live bears or the acid synthesised chemically. Despite these alternatives bears continue to be harvested from the wild. In this paper we use stated preference techniques using a random sample of the Chinese population to estimate demand functions for wild bear bile with and without competition from farmed bear bile. We find a willingness to pay considerably more for wild bear bile than farmed. Wild bear bile has low own price elasticity and cross price elasticity with farmed bear bile. The ability of farmed bear bile to reduce demand for wild bear bile is at best limited and, at prevailing prices, may be close to zero or have the opposite effect. The demand functions estimated suggest that the own price elasticity of wild bear bile is lower when competing with farmed bear bile than when it is the only option available. This means that the incumbent product may actually sell more items at a higher price when competing than when alone in the market. This finding may be of broader interest to behavioural economists as we argue that one explanation may be that as product choice increases price has less impact on decision making. For the wildlife farming debate this indicates that at some prices the introduction of farmed competition might increase the demand for the wild product.

  19. On Dynamic Nonlinear Elasticity and Small Strain

    NASA Astrophysics Data System (ADS)

    Johnson, P. A.; Sutin, A.; Guyer, R. A.; Tencate, J. A.

    2002-12-01

    We are addressing the question of whether or not there is a threshold strain behavior where anomalous nonlinear fast dynamics (ANFD) commences in rock and other similar solids, or if the elastic nonlinearity persists to the smallest measurable values. In qualitative measures of many rock types and other materials that behave in the same manner, we have not observed a threshold; however the only careful, small strain level study conducted under controlled conditions that we are aware of is that of TenCate et al. in Berea sandstone (Phys. Rev. Lett. 85, 1020-1024 (2000)). This work indicates that in Berea sandstone, the elastic nonlinearity persists to the minimum measured strains of at least 10-8. Recently, we have begun controlled experiments in other materials that exhibit ANFD in order to see whether or not they behave as Berea sandstone does. We are employing Young's mode resonance to study resonance peak shift and amplitude variations as a function of drive level and detected strain level. In this type of experiment, the time average amplitude is recorded as the sample is driven by a continuous wave source from below to above the fundamental mode resonance. The drive level is increased, and the measurement is repeated progressively over larger and larger drive levels. Experiments are conducted at ambient pressure. Pure alumina ceramic is a material that is highly, elastically-nonlinear and nonporous, and therefore the significant influence of relative humidity on elastic nonlinear response that rock suffers is avoided. Temperature is carefully monitored. Measurements on pure alumina ceramic show that, like Berea sandstone, there is no threshold of elastic nonlinearity within our measurement capability. We are now studying other solids that exhibit ANFD including rock and mixed phase metal. These results indicate that elastic nonlinearity influences all elastic measurments on these solids including modulus and Q at ambient conditions. There appears to be no

  20. BATMAN: MOS Spectroscopy on Demand

    NASA Astrophysics Data System (ADS)

    Molinari, E.; Zamkotsian, F.; Moschetti, M.; Spano, P.; Boschin, W.; Cosentino, R.; Ghedina, A.; González, M.; Pérez, H.; Lanzoni, P.; Ramarijaona, H.; Riva, M.; Zerbi, F.; Nicastro, L.; Valenziano, L.; Di Marcantonio, P.; Coretti, I.; Cirami, R.

    2016-10-01

    Multi-Object Spectrographs (MOS) are the major instruments for studying primary galaxies and remote and faint objects. Current object selection systems are limited and/or difficult to implement in next generation MOS for space and ground-based telescopes. A promising solution is the use of MOEMS devices such as micromirror arrays, which allow the remote control of the multi-slit configuration in real time. TNG is hosting a novelty project for real-time, on-demand MOS masks based on MOEMS programmable slits. We are developing a 2048×1080 Digital-Micromirror-Device-based (DMD) MOS instrument to be mounted on the Galileo telescope, called BATMAN. It is a two-arm instrument designed for providing in parallel imaging and spectroscopic capabilities. With a field of view of 6.8×3.6 arcmin and a plate scale of 0.2 arcsec per micromirror, this astronomical setup can be used to investigate the formation and evolution of galaxies. The wavelength range is in the visible and the spectral resolution is R=560 for a 1 arcsec object, and the two arms will have 2k × 4k CCD detectors. ROBIN, a BATMAN demonstrator, has been designed, realized and integrated. We plan to have BATMAN first light by mid-2016.