The Rebound Effect: A Simulation Model of Telecommuting

OpenAIRE

Reitan, Fredrik Aadne

2014-01-01

This thesis aims to highlight the relationship between telecommuting and the rebound effect with respect to greenhouse gas emissions. This was done by gathering and analyzing the latest research from various fields that could provide information about telecommuting and the rebound effect. By surveying these fields, an informative and well-documented framework for modeling telecommuting and the rebound effect was made possible. The simulation model simulated the adoption of telecommuting in Lo...

Rebounding of a shaped-charge jet

Science.gov (United States)

Proskuryakov, E. V.; Sorokin, M. V.; Fomin, V. M.

2007-09-01

The phenomenon of rebounding of a shaped-charge jet from the armour surface with small angles between the jet axis and the target surface is considered. Rebounding angles as a function of jet velocity are obtained in experiments for a copper shaped-charge jet. An engineering calculation technique is developed. The results calculated with the use of this technique are in reasonable agreement with experimental data.

Estimating the direct rebound effect for on-road freight transportation

International Nuclear Information System (INIS)

Winebrake, James J.; Green, Erin H.; Comer, Bryan; Corbett, James J.; Froman, Sarah

2012-01-01

Energy and environmental concerns have spawned new policies aimed at reducing emissions and fuel consumption of heavy-duty vehicles (HDVs) worldwide. While such policies intend to reduce HDV energy consumption and emissions, energy savings that reduce transportation costs may lead to increased demand for HDV transportation services. Increased HDV transportation, in turn, can result in increased energy use and emissions—i.e., a direct “rebound effect.” This paper provides a critical review of the literature related to the HDV rebound effect. Results of this review demonstrate that the lack of focused studies in this area combined with the variability and heterogeneity of the trucking sector limit general understanding of the HDV rebound effect. Currently, the studies that do exist often create biased or erroneous rebound effect estimates by inappropriately relying on freight elasticities or applying metrics that omit important elements of fuel consumption. Research following a more transparent and coherent approach can improve estimates of the rebound effect from policy measures to improve HDV energy efficiency. - Highlights: ► Provides a critical review of HDV rebound effect literature. ► Demonstrates limitations of HDV rebound effect estimates. ► Provides framework for considering more complete HDV rebound effect.

Rethinking economy-wide rebound measures: An unbiased proposal

International Nuclear Information System (INIS)

Guerra, Ana-Isabel; Sancho, Ferran

2010-01-01

In spite of having been first introduced in the last half of the ninetieth century, the debate about the possible rebound effects from energy efficiency improvements is still an open question in the economic literature. This paper contributes to the existing research on this issue proposing an unbiased measure for economy-wide rebound effects. The novelty of this economy-wide rebound measure stems from the fact that not only actual energy savings but also potential energy savings are quantified under general equilibrium conditions. Our findings indicate that the use of engineering savings instead of general equilibrium potential savings downward biases economy-wide rebound effects and upward-biases backfire effects. The discrepancies between the traditional indicator and our proposed measure are analysed in the context of the Spanish economy.

Exchange rate rebounds after foreign exchange market interventions

Science.gov (United States)

Hoshikawa, Takeshi

2017-03-01

This study examined the rebounds in the exchange rate after foreign exchange intervention. When intervention is strongly effective, the exchange rate rebounds at next day. The effect of intervention is reduced slightly by the rebound after the intervention. The exchange rate might have been 67.12-77.47 yen to a US dollar without yen-selling/dollar-purchasing intervention of 74,691,100 million yen implemented by the Japanese government since 1991, in comparison to the actual exchange rate was 103.19 yen to the US dollar at the end of March 2014.

The rebound effect for heavy industry: Empirical evidence from China

International Nuclear Information System (INIS)

Lin, Boqiang; Li, Jianglong

2014-01-01

Energy efficiency improvement will reduce the effective price of energy services, and hence at least partially mitigate original expected energy conservation. Therefore, the magnitude of rebound effect is important for the design and timing of an effective energy conservation policy. Under the framework of translog cost share equations, we estimates the direct rebound effect for heavy industry in China for the first time by conducting an empirical research on the relationship between the direct rebound effect and the ease with which energy services can substitute for other inputs. Additionally, asymmetric price responses are specified in the model for the rebound effect estimation. Empirical results in our paper indicate that the rebound effect for heavy industry in China is about 74.3%. This reveals that energy efficiency improvement can save energy to a certain degree since the rebound effect is less than 100% (“back-fire”), but most of the expected reduction in heavy industry energy consumption is mitigated. These findings prove that energy pricing reforms and energy taxes should be further implemented to achieve effective energy conservation in China’s 12th Five Years Plan. - Highlights: • Heavy industry is energy intensive and accounts for over 60% of China’s energy consumption. • Direct rebound effect for heavy industry in China is estimated for the first time. • Asymmetric price responses are specified in the model for the direct rebound effect estimation. • Finding the existence of direct rebound effect in China’s heavy industry with a magnitude of 74.3%. • Proving that energy pricing reforms and energy taxes should be further implemented

How to deal with the rebound effect? A policy-oriented approach

International Nuclear Information System (INIS)

Font Vivanco, David; Kemp, René; Voet, Ester van der

2016-01-01

Policy makers and environmental agencies have echoed concerns brought forward by academics about the need to address the rebound effect for achieving absolute energy and environmental decoupling. However, such concerns have generally not been translated into tangible policy action. The reasons behind this inaction are not fully understood, and much remains unknown about the status of the rebound effect issue on the policy agenda and policy pathways available. Such knowledge gaps may hamper the development of effective policies to address this issue. In this paper, we examine the extent to and ways in which the rebound effect is considered in policy documents and analyse thirteen specific policy pathways for rebound mitigation. The effectiveness of the pathways is scrutinised and conclusions are offered to mitigate rebound effects. The main policy conclusions of the paper are that an appropriate policy design and policy mix are key to avoiding undesired outcomes, such as the creation of additional rebound effects and environmental trade-offs. From the discussion, economy-wide cap-and-trade systems as well as energy and carbon taxes, when designed appropriately, emerge as the most effective policies in setting a ceiling for emissions and addressing energy use across the economy. - Highlights: •Policy inaction on the rebound effect issue is investigated for the case of Europe. •Rebound mitigation strategies and policy pathways are proposed and analysed. •Policy inaction is partly explained by the unsuccessful push from academics. •The importance of policy design and policy mix for rebound mitigation is revealed. •Economic instruments stand out in terms of rebound mitigation potential.

The macroeconomic rebound effect and the world economy

Energy Technology Data Exchange (ETDEWEB)

Barker, T.; Dagoumas, A. [Cambridge Centre for Climate Change Mitigation Research (4CMR), Department of Land Economy, University of Cambridge, 19 Silver Street, Cambridge, CB3 9PE (United Kingdom); Rubin, J. [School of Economics, University of Maine, 5782 Winslow Hall, Orono, ME 04469-5782 (United States)

2009-11-15

This paper examines the macroeconomic rebound effect for the global economy arising from energy-efficiency policies. Such policies are expected to be a leading component of climate policy portfolios being proposed and adopted in order to achieve climate stabilisation targets for 2020, 2030 and 2050, such as the G8 50% reduction target by 2050. We apply the global 'New Economics' or Post Keynesian model E3MG, developing the version reported in IPCC AR4 WG3. The rebound effect refers to the idea that some or all of the expected reductions in energy consumption as a result of energy-efficiency improvements are offset by an increasing demand for energy services, arising from reductions in the effective price of energy services resulting from those improvements. As policies to stimulate energy-efficiency improvements are a key part of climate-change policies, the likely magnitude of any rebound effect is of great importance to assessing the effectiveness of those policies. The literature distinguishes three types of rebound effect from energy-efficiency improvements: direct, indirect and economy-wide. The macroeconomic rebound effect, which is the focus of this paper, is the combination of the indirect and economy-wide effects. Estimates of the effects of no-regrets efficiency policies are reported by the International Energy Agency in World Energy Outlook, 2006, and synthesised in the IPCC AR4 WG3 report. We analyse policies for the transport, residential and services buildings and industrial sectors of the economy for the post-2012 period, 2013-2030. The estimated direct rebound effect, implicit in the IEA WEO/IPCC AR4 estimates, is treated as exogenous, based on estimates from the literature, globally about 10%. The total rebound effect, however, is 31% by 2020 rising to 52% by 2030. The total effect includes the direct effect and the effects of (1) the lower cost of energy on energy demand in the three broad sectors as well as of (2) the extra consumers

The macroeconomic rebound effect and the world economy

International Nuclear Information System (INIS)

Barker, T.; Dagoumas, A.; Rubin, J.

2009-01-01

This paper examines the macroeconomic rebound effect for the global economy arising from energy-efficiency policies. Such policies are expected to be a leading component of climate policy portfolios being proposed and adopted in order to achieve climate stabilisation targets for 2020, 2030 and 2050, such as the G8 50% reduction target by 2050. We apply the global 'New Economics' or Post Keynesian model E3MG, developing the version reported in IPCC AR4 WG3. The rebound effect refers to the idea that some or all of the expected reductions in energy consumption as a result of energy-efficiency improvements are offset by an increasing demand for energy services, arising from reductions in the effective price of energy services resulting from those improvements. As policies to stimulate energy-efficiency improvements are a key part of climate-change policies, the likely magnitude of any rebound effect is of great importance to assessing the effectiveness of those policies. The literature distinguishes three types of rebound effect from energy-efficiency improvements: direct, indirect and economy-wide. The macroeconomic rebound effect, which is the focus of this paper, is the combination of the indirect and economy-wide effects. Estimates of the effects of no-regrets efficiency policies are reported by the International Energy Agency in World Energy Outlook, 2006, and synthesised in the IPCC AR4 WG3 report. We analyse policies for the transport, residential and services buildings and industrial sectors of the economy for the post-2012 period, 2013-2030. The estimated direct rebound effect, implicit in the IEA WEO/IPCC AR4 estimates, is treated as exogenous, based on estimates from the literature, globally about 10%. The total rebound effect, however, is 31% by 2020 rising to 52% by 2030. The total effect includes the direct effect and the effects of (1) the lower cost of energy on energy demand in the three broad sectors as well as of (2) the extra consumers' expenditure

The macro-economic rebound effect and the UK economy

International Nuclear Information System (INIS)

Barker, Terry; Ekins, Paul; Foxon, Tim

2007-01-01

This paper examines the macroeconomic rebound effect for the UK economy arising from energy efficiency policies 2000-2010 using the macroeconomic model, MDM-E3. The literature distinguishes between three types of rebound effect: direct, indirect and economy-wide. The macroeconomic rebound effect considered here is the combination of the indirect and economy-wide effects. Policies for the domestic, business, commercial and public, and transport sectors of the economy are analysed for 2000-2010. Overall, the policies lead to a saving of about 8% of the energy, which would otherwise have been used and a reduction in CO 2 emissions of 10% (or 14 mtC) by 2010. There are also favourable macroeconomic effects: lower inflation and higher growth. We find that the macroeconomic rebound effect arising from UK energy efficiency policies for the period 2000-2010 is around 11% by 2010, averaged across sectors of the economy. When this is added to the (assumed) direct rebound effect of around 15%, this gives a total rebound effect of around 26% arising from these policies. Thus, the findings of the study support the argument that energy efficiency improvements for both consumers and producers, stimulated by policy incentives, will lead to significant reductions in energy demand and hence in greenhouse gas emissions

Assessing the rebound effect using a natural experiment setting: Evidence from the private transportation sector in Israel

International Nuclear Information System (INIS)

Steren, Aviv; Rubin, Ofir D.; Rosenzweig, Stav

2016-01-01

Subsidizing energy-efficient technologies is considered by energy and environmental organizations to be one of the most effective policies for decreasing energy consumption. In the transportation sector such policies are becoming ever more popular, and have been implemented in a considerable number of countries in recent years. Because these policies promote energy-efficient cars with lower usage costs, they may rebound and increase the distances traveled by households that have switched to energy-efficient cars. From an econometric perspective, a subsidization policy can be used as a valid instrument to identify the households’ choice of energy efficiency levels of the cars they own. This identification, in turn, can be utilized to account for endogeneity in the estimation of a rebound effect. The present study uses a natural experiment setting of such a policy implemented in Israel in 2009. The empirical results indicate a fairly large average rebound effect of 40%. The results also indicate that while the policy indeed encouraged the purchase of energy-efficient cars, households that bought a new or used car during the surveyed period did not generate a rebound effect of a different magnitude compared with other households that did not. We discuss the implications of our findings. - Highlights: •Subsidizing energy-efficient cars has become a popular policy in many countries. •We are unaware of studies identifying rebound via cars’ subsidization policy. •We explored a rebound in light of such a policy in Israel. •Household expenditure survey data, fuel prices and car characteristics were employed. •We found an average rebound effect of 40%.

The life cycle rebound effect of air-conditioner consumption in China

International Nuclear Information System (INIS)

Liu, Jingru; Sun, Xin; Lu, Bin; Zhang, Yunkun; Sun, Rui

2016-01-01

Highlights: • Develop a life cycle rebound effect model. • Assess the life cycle rebound effect of Chinese room air conditioners. • Conduct a questionnaire to assess the consumption behavior of Chinese room air conditioners. • Rebound effect should be considered by energy policy makers. - Abstract: Governments worldwide are attempting to reduce energy consumption and environmental pollution by confronting environmental problems and adopting more energy-efficient products. However, because of the rebound effect, energy-saving targets cannot always be fully achieved, and sometimes greater energy consumption is generated. Research on the rebound effect from the perspective of industrial ecology considers not only direct energy consumption but also its life cycle negative impacts on the environment with China’s rapid economic development and simultaneously improving quality of life, the ownership of room air conditioners (RACs) has increased more than three hundred times, and air conditioners’ energy consumption has increased one thousand times over the last twenty years. The Air Conditioner Energy Efficiency Standard is one of the most important measures in China for reducing the amount of energy consumed by RACs. This paper introduces a life cycle based method to estimate the rebound effect of Chinese RACs consumption. This model provides a product’s life-cycle view to assess the rebound effect, considering the contribution of both producer and consumer. Based on the established life cycle rebound effect model, we compared urban household RAC consumption behaviour before and after the launch of the Air Conditioner Energy Efficiency Standard. A rebound effect in RAC consumption was found that there was a longer daily usage period in the household as air conditioner efficiency levels improved. The life cycle rebound effect of household air-conditioner consumption was calculated to be 67%. The main conclusion obtained from this study is that policies and

Measuring energy rebound effect in the Chinese economy: An economic accounting approach

International Nuclear Information System (INIS)

Lin, Boqiang; Du, Kerui

2015-01-01

Estimating the magnitude of China's economy-wide rebound effect has attracted much attention in recent years. Most existing studies measure the rebound effect through the additional energy consumption from technological progress. However, in general technological progress is not equivalent to energy efficiency improvement. Consequently, their estimation may be misleading. To overcome the limitation, this paper develops an alternative approach for estimating energy rebound effect. Based on the proposed approach, China's economy-wide energy rebound effect is revisited. The empirical result shows that during the period 1981–2011 the rebound effects in China are between 30% and 40%, with an average value of 34.3%. - Highlights: • This paper develops an alternative approach for estimating energy rebound effect. • The proposed approach is based on the multilevel–hierarchical (M–H) IDA model. • The energy rebound effects in China are estimated between 30% and 40%

The rebound effect, gender and social justice: A case study in Germany

International Nuclear Information System (INIS)

Galvin, Ray

2015-01-01

Energy efficiency increases are essential in reducing energy consumption and CO 2 emissions. Policy is therefore rightly concerned about rebound effects, which cause energy and CO 2 emission reductions to be less than anticipated. A policy dilemma is emerging in that less economically privileged groups tend to show the highest rebound effects. Some studies suggest policymakers may therefore be reluctant to support energy efficiency upgrades among such groups. This paper argues this is based on a misunderstanding of the conceptual structure of the rebound effect. Firstly, a mathematical analysis confirms that the rebound effect is merely a comparison of proportions, not a measure of absolute levels of energy consumption, which are the real cause of increased CO 2 emissions. Secondly, an empirical study of commute distances in North-Rhine-Westphalia, Germany’s largest state, reveals that female commuters show considerably higher rebound effects than male commuters, both in time and cross-sectional analyses. However, male commuters consume the most energy and produce the most CO 2 emissions, by every measure. This resonates with recent studies showing the same disjunction between rebound effects and absolute consumption, in home heating among poorer and wealthier households. Policy needs to focus on absolute consumption levels and be cautious in interpreting rebound effects. - Highlights: • Economically disadvantaged groups often show the highest rebound effects. • But they usually have the lowest absolute levels of energy consumption. • A study of female vs male commuting distance rebound effects confirms this. • This is consistent with the mathematical structure the rebound effect concept. • Policymakers need to problematize high consumption, not high rebound effects.

International spillover and rebound effects from increased energy efficiency in Germany

International Nuclear Information System (INIS)

Koesler, Simon; Swales, Kim; Turner, Karen

2016-01-01

The pollution/energy leakage literature raises the concern that policies implemented in one country, such as a carbon tax or tight energy restrictions, might simply result in the reallocation of energy use to other countries. This paper addresses these concerns in the context of policies to increase energy efficiency, rather than direct action to reduce energy use. Using a global CGE simulation model, we extend the analyses of ‘economy-wide’ rebound from the national focus of previous studies to incorporate international spill-over effects from trade in goods and services. Our focus is to investigate whether these effects have the potential to increase or reduce the overall (global) rebound of local energy efficiency improvements. In the case we consider, increased energy efficiency in German production generates changes in comparative advantage that produce negative leakage effects, thereby actually rendering global rebound less than national rebound. - Highlights: • Offers first CGE analysis of full global spill-over effects of energy efficiency • Derives rebound definitions at sector, all industry, economy-wide and global levels • Extends understanding of how rebound extends from industry to global economy levels • Shows that changes in comparative advantage may constrain global rebound effects

The determinants of fuel use in the trucking industry - volume, fleet characteristics and the rebound effect

DEFF Research Database (Denmark)

de Borger, Bruno; Mulalic, Ismir

2012-01-01

This paper studies the determinants of fuel use in the trucking industry in Denmark, using aggregate time series data for the period 1980–2007. The model captures the main linkages between the demand for freight transport, the characteristics of the vehicle fleet, and the demand for fuel. Results...... of this effect is approximately 10% in the short run and 17% in the long run, so that a 1% improvement in fuel efficiency reduces fuel use by 0.90% (short-run) to 0.83% (long-run). Second, we find that higher fuel prices raise the average capacity of trucks, and they induce firm sto invest in newer, typically...... more fuel efficient, trucks. Third, these adjustments and the rebound effect jointly imply that the effect of higher fuel prices on fuel use in the trucking industry is fairly small; estimated price elasticities are _0:13 and _0:22 in the short run and in the long run, respectively. The empirical...

Exploring energy rebound effects

NARCIS (Netherlands)

Heijs, W.J.M.; Adrians, R.

2011-01-01

In the debate on sustainable energy use, one important aspect tends to be systematically overlooked. Sustainability may be increased by developing technological innovations and measures to promote energy conservation, but so-called rebound effects constitute a potential and largely underestimated

Numerical study of droplet impact and rebound on superhydrophobic surface

Science.gov (United States)

Cai, Xuan; Wu, Yanchen; Woerner, Martin; Frohnapfel, Bettina

2017-11-01

Droplet impact and rebound on superhydrophobic surface is an important process in many applications; among them are developing self-cleaning or anti-icing materials and limiting liquid film formation of Diesel Exhaust Fluid (DEF) in exhaust gas pipe. In the latter field, rebound of DEF droplet from wall is desired as an effective mean for avoiding or reducing unwanted solid deposition. Our goal is to numerically study influence of surface wettability on DEF droplet impact and rebound behavior. A phase-field method is chosen, which was implemented in OpenFOAM by us and validated for wetting-related interfacial flow problems. In the present contribution we first numerically reproduce relevant experimental studies in literature, to validate the code for droplet impact and rebound problem. There we study droplet-surface contact time, maximum/instantaneous spreading factor and droplet shape evolution. Our numerical results show good agreement with experimental data. Next we investigate for DEF droplets the effects of diameter, impact velocity and surface wettability on rebound behavior and jumping height. Based on Weber number and equilibrium contact angle, two regimes are identified. We show that surface wettability is a deciding factor for achieving rebound event. This work is supported by Foundation ``Friedrich-und-Elisabeth Boysen Stiftung fuer Forschung und Innovation'' (BOY-127-TP1).

Re-spending rebound: A macro-level assessment for OECD countries and emerging economies

International Nuclear Information System (INIS)

Antal, Miklós; Bergh, Jeroen C.J.M. van den

2014-01-01

It is well-known that energy conservation can lead to rebound effects that partly offset the original energy savings. One particular rebound mechanism is re-spending of money savings associated with energy savings on energy intensive goods or services. We calculate the average magnitude of this “re-spending rebound” for different fuels and countries, and for both energy and carbon (CO 2 ) emissions. We find that emerging economies, neglected in past studies, typically have larger rebounds than OECD countries. Since such economies play an increasingly important role in the global economy the re-spending rebound is a growing concern. The re-spending effect is generally larger for gasoline than for natural gas and electricity. Paradoxically, stronger financial incentives to conserve energy tend to increase the rebound. This suggests that with climate regulation and peak oil the re-spending rebound may become more important. We discuss the policy implications of our findings. - highlights: • Energy and carbon rebound due to re-spending of money savings is analyzed. • The average magnitude of this rebound is calculated for several countries. • Emerging economies typically have substantially larger rebounds than OECD countries. • The effect is generally stronger for gasoline than for natural gas and electricity. • Policy conclusions are drawn

An empirical study of direct rebound effect for passenger transport in urban China

International Nuclear Information System (INIS)

Wang, H.; Zhou, P.; Zhou, D.Q.

2012-01-01

Transport sector accounts for about 8% of total energy consumption in China and this share will likely increase in the visible future. Improving energy efficiency has been considered as a major way for reducing transport energy use, whereas its effectiveness might be affected by the rebound effect. This paper estimates the direct rebound effect for passenger transport in urban China by using the linear approximation of the Almost Ideal Demand System model and simulation analysis. Our empirical results reveal the existence of direct rebound effect for passenger transport in urban China. A majority of the expected reduction in transport energy consumption from efficiency improvement could be offset due to the existence of rebound effect. We have further investigated the relationship between the magnitude of direct rebound effect and households' expenditure. It was found that the direct rebound effect for passenger transport tends to decline with the increase of per capita household consumption expenditure. - Highlights: ► The magnitude of direct rebound effect for urban passenger transport in China is 96%. ► The rebound effect in China could be larger than that in developed countries. ► The rebound effect in China declined with the increase of per capita expenditure.

A Comparative Analysis of the Rebound Hammer and Ultrasonic ...

African Journals Online (AJOL)

This work presents a study on the comparison between some non-destructive testing tech-niques (Rebound Hammer and Ultrasonic Pulse Velocity). Tests were performed to com-pare the accuracy between the rebound hammer and the ultrasonic pulse velocity methodin estimating the strength of concrete. Eighty samples ...

The energy-economy-environment interaction and the rebound-effect

NARCIS (Netherlands)

Musters, A.P.A.

1995-01-01

This study examines the Energy-Economy-Environment (3-E) interaction ingeneral and the rebound-effect in particular. The rebound-effect can be defined as that part of the initially expected energy savings, resulting from energy efficiency improvements, that is lost because of the 3-E interaction. To

The direct and indirect CO_2 rebound effect for private cars in China

International Nuclear Information System (INIS)

Zhang, Yue-Jun; Liu, Zhao; Qin, Chang-Xiong; Tan, Tai-De

2017-01-01

The quantity of China's private cars has increased dramatically in the past decade, which has become one of the key sources of carbon emission and air pollution in the cities of China. In theory, to improve energy efficiency can reduce carbon emission significantly, but the result may be affected by the rebound effect. This paper utilizes a two-stage Almost Ideal Demand System (AIDS) model to estimate the total CO_2 rebound effect for China's private cars during 2001–2012 at the provincial level, then uses a panel data model to analyze its impact factors. The results suggest that, first of all, the CO_2 emissions of private cars have the super conservation effect, partial rebound effect and backfire effect among provinces in China. And the direct CO_2 rebound effect plays a dominant role in the total CO_2 rebound effect in most provinces. Second, the total CO_2 rebound effect of private cars among China's provinces presents an overall convergence trend over time. Finally, the household expenditure and the population density have a negative and positive influence on the total CO_2 rebound effect for China's private cars, respectively. - Highlights: • Private cars have become the key source of carbon emission in China. • This paper employs a two-stage Almost Ideal Demand System (AIDS) model • The direct and indirect CO_2 rebound effects for China's private cars are estimated. • The direct CO_2 rebound effect plays a dominant role in the total CO_2 rebound effect in most provinces. • The total CO_2 rebound effect among China's provinces has a convergence over time.

Drop rebound after impact: the role of the receding contact angle.

Science.gov (United States)

Antonini, C; Villa, F; Bernagozzi, I; Amirfazli, A; Marengo, M

2013-12-31

Data from the literature suggest that the rebound of a drop from a surface can be achieved when the wettability is low, i.e., when contact angles, measured at the triple line (solid-liquid-air), are high. However, no clear criterion exists to predict when a drop will rebound from a surface and which is the key wetting parameter to govern drop rebound (e.g., the "equilibrium" contact angle, θeq, the advancing and the receding contact angles, θA and θR, respectively, the contact angle hysteresis, Δθ, or any combination of these parameters). To clarify the conditions for drop rebound, we conducted experimental tests on different dry solid surfaces with variable wettability, from hydrophobic to superhydrophobic surfaces, with advancing contact angles 108° contact angles 89° contact angle is the key wetting parameter that influences drop rebound, along with surface hydrophobicity: for the investigated impact conditions (drop diameter 2.4 contact angles higher than 100°. Also, the drop rebound time decreased by increasing the receding contact angle. It was also shown that in general care must be taken when using statically defined wetting parameters (such as advancing and receding contact angles) to predict the dynamic behavior of a liquid on a solid surface because the dynamics of the phenomenon may affect surface wetting close to the impact point (e.g., as a result of the transition from the Cassie-Baxter to Wenzel state in the case of the so-called superhydrophobic surfaces) and thus affect the drop rebound.

Missing carbon reductions? Exploring rebound and backfire effects in UK households

International Nuclear Information System (INIS)

Druckman, Angela; Chitnis, Mona; Sorrell, Steve; Jackson, Tim

2011-01-01

Households are expected to play a pivotal role in reducing the UK's greenhouse gas (GHG) emissions, and the UK Government is encouraging specific household actions to help meet its targets. However, due to the rebound effect, only a portion of the GHG emission reductions estimated by simple engineering calculations are generally achieved in practice. For example, replacing short car journeys by walking or cycling reduces consumption of motor fuels. But this frees up money that may be spent on, for example, purchasing extra clothes or flying on vacation. Alternatively, the money may be put into savings. Since all of these options lead to GHG emissions, total GHG savings may be less than anticipated. Indeed, in some instances, emissions may increase-a phenomenon known as 'backfire'. We estimate that the rebound effect for a combination of three abatement actions by UK households is approximately 34%. Targeting re-spending on goods and services with a low GHG intensity reduces this to a minimum of around 12%, while re-spending on goods and services with a high GHG intensity leads to backfire. Our study highlights the importance of shifting consumption to lower GHG intensive categories and investing in low carbon investments. - Highlights: → Policy-makers should be mindful of the rebound effect when developing strategies. → Due to rebound, only around two thirds of expected GHG reductions may be achieved. → Re-use of avoided expenditure is critical; in extreme case backfire may occur. → Higher savings reduce rebound: 'green' investments minimise rebound. → Theoretically negative rebound is possible through 'green' technology investment.

Turning lights into flights: Estimating direct and indirect rebound effects for UK households

International Nuclear Information System (INIS)

Chitnis, Mona; Sorrell, Steve; Druckman, Angela; Firth, Steven K.; Jackson, Tim

2013-01-01

Energy efficiency improvements by households lead to rebound effects that offset the potential energy and emissions savings. Direct rebound effects result from increased demand for cheaper energy services, while indirect rebound effects result from increased demand for other goods and services that also require energy to provide. Research to date has focused upon the former, but both are important for climate change. This study estimates the combined direct and indirect rebound effects from seven measures that improve the energy efficiency of UK dwellings. The methodology is based upon estimates of the income elasticity and greenhouse gas (GHG) intensity of 16 categories of household goods and services, and allows for the embodied emissions of the energy efficiency measures themselves, as well as the capital cost of the measures. Rebound effects are measured in GHG terms and relate to the adoption of these measures by an average UK household. The study finds that the rebound effects from these measures are typically in the range 5–15% and arise mostly from indirect effects. This is largely because expenditure on gas and electricity is more GHG-intensive than expenditure on other goods and services. However, the anticipated shift towards a low carbon electricity system in the UK may lead to much larger rebound effects. - Highlights: ► We estimate the direct and indirect rebound effects from energy efficiency improvements by UK households. ► We allow for the capital cost of the improvement, together with the emissions embodied in the relevant equipment. ► We find rebound effects to be relatively modest, in the range 5–15%. ► The anticipated shift towards a low carbon electricity system will lead to larger rebound effects

The energy rebound effects across China’s industrial sectors: An output distance function approach

International Nuclear Information System (INIS)

Li, Ke; Zhang, Ning; Liu, Yanchu

2016-01-01

Highlights: • Output distance function for the energy rebound effect is developed. • The aggregate energy rebound effect of China is 88.42%. • Investment-driven economic growth is not conducive to energy-saving. - Abstract: Improving energy efficiency sustainability is a target of the Chinese government. However, the effectiveness of energy conservation policy is affected by the energy rebound effect under which energy efficiency improvement reduces the effective price of energy services, thereby completely or partially offsetting the energy saved by efficiency improvement. Based on the output distance function, this paper develops an improved estimation model of the energy rebound effect, which is logically consistent with the quantities of energy savings and energy rebounds induced by technological progress. Results show that the aggregate energy rebound effect of 36 industrial sectors in China over 1998–2011 is 88.42%, which implies that most of the expected energy savings are mitigated. Investment-driven economic growth is not conducive to energy-saving and results in a strong energy rebound effect in the following year. The equipment and high-end manufacturing sectors have low levels of rebound effect, indicating that increasing the proportion of such firms in the total manufacturing sector can improve the performance of energy conservation. The high level and heterogeneity in rebound effects strongly suggest that varies strategies are necessary for energy conservation among China’s industrial sectors.

How organizational and global factors condition the effects of energy efficiency on CO_2 emission rebounds among the world's power plants

International Nuclear Information System (INIS)

Grant, Don; Jorgenson, Andrew K.; Longhofer, Wesley

2016-01-01

The United Nations Intergovernmental Panel on Climate Change (IPCC), the International Energy Agency (IEA), and several nations suggest that energy efficiency is an effective strategy for reducing energy consumption and associated greenhouse gas emissions. Skeptics contend that because efficiency lowers the price of energy and energy services, it may actually increase demand for them, causing total emissions to rise. While both sides of this debate have researched the magnitude of these so-called rebound effects among end-use consumers, researchers have paid less attention to the conditions under which direct rebounds cause CO_2 emissions to rise among industrial producers. In particular, researchers have yet to explore how organizational and global factors might condition the effects of efficiency on emissions among power plants, the world's most concentrated sources of anthropogenic greenhouse gases. Here we use a unique dataset containing nearly every fossil-fuel power plant in the world to determine whether the impact of efficiency on emissions varies by plants' age, size, and location in global economic and normative systems. Findings reveal that each of these factors has a significant interaction with efficiency and thus shapes environmentally destructive rebound effects. - Highlights: •Skeptics charge that energy efficiency may actually cause CO_2 emissions to rise. •Few have examined whether such rebound effects occur among power plants. •Little also known about whether plants' organizational and global characteristics condition rebounds. •Conduct first analysis of rebound effects among the world's power plants. •Rebounds found to depend on plants' age, size, and location in international economic and normative systems.

Factor substitution and rebound effect in China’s food industry

International Nuclear Information System (INIS)

Lin, Boqiang; Xie, Xuan

2015-01-01

Highlights: • The basic information of China’s food industry is introduced in detail. • Inter-factor substitution relationship in China’s food industry is analyzed. • Direct rebound effect in the industry is measured. • Several relevant policy suggestions about energy conservation are provided. - Abstract: Energy efficiency improvement can reduce the energy consumption of an industry, and thus promote energy conservation. However, the reduction of effective energy prices caused by energy efficiency improvement will lower energy costs for enterprises, making them substitute energy for other input factors. Therefore, energy conservation brought about by efficiency improvement will be partly offset. This offset is called the energy rebound effect of an industry. This paper estimates the system of cost share equations in China’s food industry, analyzes the substitution relationship between each input factor, and calculates the direct rebound effect. The results show that: there exist substitution relationships between energy and other input factors, among which the substitution elasticity between energy and labor is the biggest, and the substitution of energy for capital dominates that of capital for energy. The direct rebound effect is approximately 34.39%, which means that about 34.39% of energy conservation caused by energy efficiency enhancement in the industry has been offset by the rebound effect. The paper proposes some policy suggestions on energy conservation according to the results of substitution relationship among input factors and the rebound effect of the industry. The policy suggestions include reducing the capital and labor costs of the food industry by decreasing financing costs of small businesses, optimizing personnel management, and rationalizing the energy pricing mechanism to form a reasonable energy price.

Estimating direct and indirect rebound effects by supply-driven input-output model: A case study of Taiwan's industry

International Nuclear Information System (INIS)

Wu, Kuei-Yen; Wu, Jung-Hua; Huang, Yun-Hsun; Fu, Szu-Chi; Chen, Chia-Yon

2016-01-01

Most existing literature focuses on the direct rebound effect on the demand side for consumers. This study analyses direct and indirect rebound effects in Taiwan's industry from the perspective of producers. However, most studies on the producers' viewpoint may overlook inter-industry linkages. This study applies a supply-driven input-output model to quantify the magnitude of rebound effects by explicitly considering inter-industry linkages. Empirical results showed that total rebound effects for most Taiwan's sectors were less than 10% in 2011. A comparison among the sectors yields that sectors with lower energy efficiency had higher direct rebound effects, while sectors with higher forward linkages generated higher indirect rebound effects. Taking the Mining sector (S3) as an example, which is an upstream supplier and has high forward linkages; it showed high indirect rebound effects that are derived from the accumulation of additional energy consumption by its downstream producers. The findings also showed that in almost all sectors, indirect rebound effects were higher than direct rebound effects. In other words, if indirect rebound effects are neglected, the total rebound effects will be underestimated. Hence, the energy-saving potential may be overestimated. - Highlights: • This study quantifies rebound effects by a supply-driven input-output model. • For most Taiwan's sectors, total rebound magnitudes were less than 10% in 2011. • Direct rebound effects and energy efficiency were inverse correlation. • Indirect rebound effects and industrial forward linkages were positive correlation. • Indirect rebound effects were generally higher than direct rebound effects.

Heterogeneity in rebound effects: Estimated results and impact of China’s fossil-fuel subsidies

International Nuclear Information System (INIS)

Li, Ke; Lin, Boqiang

2015-01-01

Highlights: • Rebound effects for China’s sectors are estimated. • The input–output model is a suitable model to analysis energy rebound effects across sectors. • The impacts of fossil-fuel subsidies on rebound effects are evaluated. • Technological progress has varies impactions on energy conservation, thereby rebound effects. - Abstract: Improving energy efficiency through technological advancement has become a primary measure to achieve energy conservation targets in China. However, the existence of energy rebound effects may completely or partially offset energy savings associated with technological advancement. From sectors perspective, technological advancement is not a necessary condition for energy conservation for a given sector because of varied rates of technological advancement and dependence among sectors. Adopting the input–output model, this article presents a detailed analysis of energy rebound effects in China’s economy at the aggregate and sectoral level over 2006–2010. The results show that the aggregate sectors’ rebound effect is about 11.31%, which is larger than without considering the interaction among sectors (11.25%); and strongly suggests that technological advancement has varied impacts on energy conservation and rebound effects. Thus various strategies of technological advancement and incorporated mitigation measures are necessary for energy conservation across sectors. Furthermore, the current study confirms that China’s total value of fossil-fuel subsidies reached 160.23 billion US$ (constant 2005 price) in 2006–2010; and after removal of subsidies, the energy use is expected to save 411.35 million toe and the rebound effects for aggregate sectors become 10.64%. Finally, some relevant policy issues are discussed in depth

Modification of General Research Corporation (GRC) Dynatup 8200 Drop Tower Rebounding Brake System

Science.gov (United States)

2016-08-01

Rebounding Brake System by David Gray, Robert Kaste, and Bradley Lawrence Approved for public release; distribution is...Research Laboratory Modification of General Research Corporation (GRC) Dynatup 8200 Drop Tower Rebounding Brake System by David Gray and...Research Corporation (GRC) Dynatup 8200 Drop Tower Rebounding Brake System 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

Rebound effect in Chinese household energy efficiency and solution for mitigating it

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Jinlong; Long, Enshen [College of Architecture and Environment, Sichuan University, Chengdu 610065 (China); Hokao, Kazunori [Department of Civil Engineering, Saga University, Saga, 840-8502 (Japan)

2010-12-15

The current efforts and technologies on energy efficiency seem unable to hold back the increasing momentum of the household energy consumption per unit of China, which has been on the increase since 2000. Usually, this phenomenon is simply attributed to the demand for more comfortable household lifestyle due to the current rapid economic development of China. However, the latent cause - rebound effect has long been ignored in the household energy efficiency of China, while it has been analyzed deeply and recognized widely all over the world. This article studies the rebound effect in the household energy efficiency of China and its related negative influence on the energy demand. A high rebound effect of at least 30% in the household energy efficiency of China is presumed by reference to the rebound effects of other countries. Finally, five feasible ways are summarized to mitigate the rebound effect and their values are analyzed respectively: (1) develop renewable energy resources, (2) increase energy prices, (3) improve energy efficiency, (4) build rational energy prices system, and (5) improve consumer behavior. (author)

Rebound effect in Chinese household energy efficiency and solution for mitigating it

International Nuclear Information System (INIS)

Ouyang, Jinlong; Long, Enshen; Hokao, Kazunori

2010-01-01

The current efforts and technologies on energy efficiency seem unable to hold back the increasing momentum of the household energy consumption per unit of China, which has been on the increase since 2000. Usually, this phenomenon is simply attributed to the demand for more comfortable household lifestyle due to the current rapid economic development of China. However, the latent cause-rebound effect has long been ignored in the household energy efficiency of China, while it has been analyzed deeply and recognized widely all over the world. This article studies the rebound effect in the household energy efficiency of China and its related negative influence on the energy demand. A high rebound effect of at least 30% in the household energy efficiency of China is presumed by reference to the rebound effects of other countries. Finally, five feasible ways are summarized to mitigate the rebound effect and their values are analyzed respectively: (1) develop renewable energy resources, (2) increase energy prices, (3) improve energy efficiency, (4) build rational energy prices system, and (5) improve consumer behavior.

Rebound effects from speed and acceleration in electric and internal combustion engine cars: An empirical and conceptual investigation

International Nuclear Information System (INIS)

Galvin, Ray

2016-01-01

Highlights: • Vehicle rebound effects have been investigated for distance but not speed. • We investigate speed rebounds for an e- and an ICE-car in controlled lab tests. • We develop a mathematical model to include these with distance rebound effects. • The e-car shows 20% speed rebound comparing 1975 and modern driving styles. • The ICE-car shows speed rebound due to lock-in from auto gear ratios. - Abstract: Rebound effect studies of road vehicle travel focus mostly on increases in distance traveled after increases in energy efficiency. Average journeying speed also increases with energy efficiency, but rebound studies avoid quantifying speed-related rebound effects. This may underestimate rebound effects by around 60%. This study offers a first attempt to show how increases in speed and acceleration contribute to rebound effects, and how these can be quantified. Its empirical data is dynamometer test results for a plug-in electric car and an internal combustion engine (ICE) pick-up van with automatic transmission, each on the WLTP and NEDC drive cycles, representing driving styles from today and 1975 respectively. Rebound effects are estimated by comparing the WLTP and NEDC results, using typical 1975 energy efficiencies for the NEDC. The electric car shows a 20.5% speed rebound effect, and a mathematical development sets out how speed rebound effects can be included in traditional rebound effect analyses. Results for the ICE-vehicle do not allow a direct rebound effect estimate due to wasteful engine revving on the NEDC and wrong gear ratios for sedate travel. However, this can be seen as a form of ‘transformational’ rebound effect, where vehicle design locks drivers into fast driving styles.

Delay-induced rebounds in CO2 emissions and critical time-scales to meet global warming targets

Science.gov (United States)

Manoli, Gabriele; Katul, Gabriel G.; Marani, Marco

2016-12-01

While climate science debates are focused on the attainment of peak anthropogenic CO2 emissions and policy tools to reduce peak temperatures, the human-energy-climate system can hold "rebound" surprises beyond this peak. Following the second industrial revolution, global per capita CO2 emissions (cc) experienced a punctuated growth of about 100% every 60 years, mainly attributable to technological development and its global spread. A model of the human-energy-climate system capable of reproducing past punctuated dynamics shows that rebounds in global CO2 emissions emerge due to delays intrinsic to the diffusion of innovations. Such intrinsic delays in the adoption and spread of low-carbon emitting technologies, together with projected population growth, upset the warming target set by the Paris Agreement. To avoid rebounds and their negative climate effects, model calculations show that the diffusion of climate-friendly technologies must occur with lags one-order of magnitude shorter (i.e., ˜6 years) than the characteristic timescale of past punctuated growth in cc. Radically new strategies to globally implement the technological advances at unprecedented rates are needed if the current emission goals are to be achieved.

Rebound Attack on the Full LANE Compression Function

DEFF Research Database (Denmark)

Matusiewicz, Krystian; Naya-Plasencia, Maria; Nikolic, Ivica

2009-01-01

In this work, we apply the rebound attack to the AES based SHA-3 candidate Lane. The hash function Lane uses a permutation based compression function, consisting of a linear message expansion and 6 parallel lanes. In the rebound attack on Lane, we apply several new techniques to construct...... a collision for the full compression function of Lane-256 and Lane-512. Using a relatively sparse truncated differential path, we are able to solve for a valid message expansion and colliding lanes independently. Additionally, we are able to apply the inbound phase more than once by exploiting the degrees...

The Rebound Attack: Cryptanalysis of Reduced Whirlpool and Grøstl

DEFF Research Database (Denmark)

Mendel, Florian; Rechberger, Christian; Schläffer, Martin

2009-01-01

of an inbound phase with a match-in-the-middle part to exploit the available degrees of freedom, and a subsequent probabilistic outbound phase. Especially on AES based hash functions, the rebound attack leads to new attacks for a surprisingly high number of rounds. We use the rebound attack to construct...

Characterisation of rebound depolarisation in mice deep dorsal horn neurons in vitro.

Science.gov (United States)

Rivera-Arconada, Ivan; Lopez-Garcia, Jose A

2015-09-01

Spinal dorsal horn neurons constitute the first relay for pain processing and participate in the processing of other sensory, motor and autonomic information. At the cellular level, intrinsic excitability is a factor contributing to network function. In turn, excitability is set by the array of ionic conductance expressed by neurons. Here, we set out to characterise rebound depolarisation following hyperpolarisation, a feature frequently described in dorsal horn neurons but never addressed in depth. To this end, an in vitro preparation of the spinal cord from mice pups was used combined with whole-cell recordings in current and voltage clamp modes. Results show the expression of H- and/or T-type currents in a significant proportion of dorsal horn neurons. The expression of these currents determines the presence of rebound behaviour at the end of hyperpolarising pulses. T-type calcium currents were associated to high-amplitude rebounds usually involving high-frequency action potential firing. H-currents were associated to low-amplitude rebounds less prone to elicit firing or firing at lower frequencies. For a large proportion of neurons expressing both currents, the H-current constitutes a mechanism to ensure a faster response after hyperpolarisations, adjusting the latency of the rebound firing. We conclude that rebound depolarisation and firing are intrinsic factors to many dorsal horn neurons that may constitute a mechanism to integrate somatosensory information in the spinal cord, allowing for a rapid switch from inhibited-to-excited states.

Living up to expectations: Estimating direct and indirect rebound effects for UK households

International Nuclear Information System (INIS)

Chitnis, Mona; Sorrell, Steve

2015-01-01

This study estimates the combined direct and indirect rebound effects from various types of energy efficiency improvement by UK households. In contrast to most studies of this topic, we base our estimates on cross-price elasticities and therefore capture both the income and substitution effects of energy efficiency improvements. Our approach involves estimating a household demand model to obtain price and expenditure elasticities of different goods and services, utilising a multiregional input–output model to estimate the GHG emission intensities of those goods and services, combining the two to estimate direct and indirect rebound effects, and decomposing those effects to reveal the relative contribution of different mechanisms and commodities. We estimate that the total rebound effects are 41% for measures that improve the efficiency of domestic gas use, 48% for electricity use and 78% for vehicle fuel use. The primary source of this rebound is increased consumption of the cheaper energy service (i.e. direct rebound) and this is primarily driven by substitution effects. Our results suggest that the neglect of substitution effects may have led prior research to underestimate the total rebound effect. However, we provide a number of caveats to this conclusion, as well as indicating priorities for future research.

Modelling the rebound effect with network theory: An insight into the European freight transport sector

International Nuclear Information System (INIS)

Ruzzenenti, Franco; Basosi, Riccardo

2017-01-01

This paper presents a two pronged approach to the study of the rebound effect, with the aim of assessing the magnitude of the effect in the European freight transport sector and proposing a new modelling framework based on network theory. The (direct) rebound effect is assessed with: 1) an econometric regression; 2) a model based on network theory and statistical mechanics. According to the econometric model the European road freight transport sector undergone a negative rebound between of −74% between 1998 and 2007 and −146% between 1998 and 2011. The network analysis delivers an estimation of network rebound ranging between −29.37% and −7.25. Overall, these results indicate that energy efficiency in Europe, between 1998 and 2011, succeed in reducing the energy consumptions amid an increasing demand for transports. Results on rebound estimation depend on the decision of using GDP as an exogenous variable, an assumption that leaves questions open about the causality chain between growth and transports. Furthermore, the network analysis highlights a structural change –a migration of production factors offshore, that might partially explain this negative effect. In this view, rebound effect analysis on a local or regional scale is becoming more and more uncertain in a globally interconnected economic context. - Highlights: • An evaluation of direct rebound effect in the freight transports with an econometric model is performed. • A new concept of rebound effect based on network theory is presented and implemented. • A comparative analysis of the two different approaches is developed. • Both models indicate that the there was a negative rebound effect in European freight transports. • Network theory proved to be a promising approach to energy systems and rebound effect modelling.

Does the Circular Economy Grow the Pie? The Case of Rebound Effects From Smartphone Reuse

Directory of Open Access Journals (Sweden)

Tamar Makov

2018-05-01

Full Text Available The environmental benefits of the circular economy (CE are often taken for granted. There are, however, reasons to believe that rebound effects may counteract such benefits by increasing overall consumption or “growing the pie.” In this study, we focus on two main rebound mechanisms: (1 imperfect substitution between “re-circulated” (recycled, reused, etc. and new products and (2 re-spending due to economic savings. We use the case study of smartphone reuse in the US to quantify, for the first time, rebound effects from reuse. Using a combination of life cycle assessment, sales statistics, consumer surveying, consumer demand modeling, and environmentally-extended input-output analysis, we quantify the magnitude of this rebound effect for life-cycle greenhouse gas emissions. We find a rebound effect of 29% on average, with a range of 27–46% for specific smartphone models. Moreover, when exploring how rebound might play out in other regions and under different consumer behavior patterns, we find that rebound effects could be higher than 100% (backfire effect. In other words, we estimate that about one third, and potentially the entirety, of emission savings resulting from smartphone reuse could be lost due to the rebound effect. Our results thus suggest that there are grounds to challenge the premise that CE strategies, and reuse in particular, always reduce environmental burdens.

Could the beta rebound in the EEG be suitable to realize a "brain switch"?

Science.gov (United States)

Pfurtscheller, G; Solis-Escalante, T

2009-01-01

Performing foot motor imagery is accompanied by a peri-imagery ERD and a post-imagery beta ERS (beta rebound). Our aim was to study whether the post-imagery beta rebound is a suitable feature for a simple "brain switch". Such a brain switch is a specifically designed brain-computer interface (BCI) with the aim to detect only one predefined brain state (e.g. EEG pattern) in ongoing brain activity. One EEG (Laplacian) recorded at the vertex during cue-based brisk foot motor imagery was analysed in 5 healthy subjects. The peri-imagery ERD and the post-imagery beta rebound (ERS) were analysed in detail between 6 and 40Hz and classified with two support vector machines. The ERD was detected in ongoing EEG (simulation of asynchronous BCI) with a true positive rate (TPR) of 28.4%+/-13.5 and the beta rebound with a TPR of 59.2%+/-20.3. In single runs with 30 cues each, the TPR for beta rebound detection was 78.6%+/-12.8. The false positive rate was always kept below 10%. The findings suggest that the beta rebound at Cz during foot motor imagery is a relatively stable and reproducible phenomenon detectable in single EEG trials. Our results indicate that the beta rebound is a suitable feature to realize a "brain switch" with one single EEG (Laplacian) channel only.

Validation Testing of a Peridynamic Impact Damage Model Using NASA's Micro-Particle Gun

Science.gov (United States)

Baber, Forrest E.; Zelinski, Brian J.; Guven, Ibrahim; Gray, Perry

2017-01-01

Through a collaborative effort between the Virginia Commonwealth University and Raytheon, a peridynamic model for sand impact damage has been developed1-3. Model development has focused on simulating impacts of sand particles on ZnS traveling at velocities consistent with aircraft take-off and landing speeds. The model reproduces common features of impact damage including pit and radial cracks, and, under some conditions, lateral cracks. This study focuses on a preliminary validation exercise in which simulation results from the peridynamic model are compared to a limited experimental data set generated by NASA's recently developed micro-particle gun (MPG). The MPG facility measures the dimensions and incoming and rebound velocities of the impact particles. It also links each particle to a specific impact site and its associated damage. In this validation exercise parameters of the peridynamic model are adjusted to fit the experimentally observed pit diameter, average length of radial cracks and rebound velocities for 4 impacts of 300 µm glass beads on ZnS. Results indicate that a reasonable fit of these impact characteristics can be obtained by suitable adjustment of the peridynamic input parameters, demonstrating that the MPG can be used effectively as a validation tool for impact modeling and that the peridynamic sand impact model described herein possesses not only a qualitative but also a quantitative ability to simulate sand impact events.

What if consumers decided to all ‘go green’? Environmental rebound effects from consumption decisions

International Nuclear Information System (INIS)

Murray, Cameron K.

2013-01-01

Shifting consumer preferences towards ‘green’ consumption is promoted by many governments and environmental groups. Rebound effects, which reduce the effectiveness of such actions, are estimated for cost-saving ‘green’ consumption choices using Australian data. Cases examined are: reduced vehicle use, reduced electricity use, changing to smaller passenger vehicles, and utilising fluorescent lighting. It is found that if rebound effects are ignored when evaluating ‘green’ consumption, environmental benefits will be overstated by around 20% for reduced vehicle use, and 7% for reduced electricity use. Rebound effects are higher, and environmental benefits lower, when more efficient vehicles or lighting are utilised rather than simple conservation actions of forgoing use. In addition, lower income households have higher rebound effects, suggesting that environmental policy directed at changing consumer behaviour is most effective when targeted at high income households. An inherent trade-off between economic and environmental benefits of ‘green’ consumption choices is demonstrated. The size of the rebound effect, and the observed variation with household income, is attributed to Life-Cycle Analysis (LCA) methodologies associated with the calculation of embodied GHG emissions of consumption goods. These results should be therefore be interpreted as the minimum rebound effect to include in policy evaluation. - Highlights: ► Rebound effects are estimated for cost-saving ‘green’ consumption choices. ► Household demand model utilised with LCA embodied GHG emissions data. ► Rebound effects are 4–24% for electricity and motor fuel conservation. ► Rebound effect declines with household income, increases with more cost savings. ► Conservation choices better than replacing household capital

The impacts of removing energy subsidies on economy-wide rebound effects in China: An input-output analysis

International Nuclear Information System (INIS)

Li, Ke; Jiang, Zhujun

2016-01-01

Facing with the increasing contradiction of economic growth, energy scarcity and environmental deterioration, energy conservation and emissions abatement have been ambitious targets for the Chinese government. Improving energy efficiency through technological advancement is a primary measure to achieve these targets. However, the existence of energy rebound effects may completely or partially offset energy savings associated with technological advancement. This paper adopted a modified input-output model to estimate the economy-wide energy rebound effects across China's economic sectors with the consideration of energy subsidies. The empirical results show that the aggregate rebound effect of China is about 1.9% in 2007–2010, thus technological advancement significantly restrains energy consumption increasing. Removing energy subsidies will cause the aggregate rebound effect declines to 1.53%. Specifically, removing subsidies for coal and nature gas can reduce the rebound effects signifcantly, while removing the subsidies for oil products has a small impact on rebound effect. The existence of rebound effects implies that technological advancement should be cooperated with energy price reform so as to achieve the energy saving target. In addition, the government should consider the diversity of economic sectors and energy types when design the reform schedule. - Highlights: • Rebound effects with the consideration of energy subsidies are estimated in China. • When considering the interactions among sectors, the aggregate rebound effect become small. • Removing subsidies will reduce energy consumption, thereby declining the rebound effects. • Removing subsidies for different energy types has varies effects on rebound effect.

Rebound Syndrome in Patients With Multiple Sclerosis After Cessation of Fingolimod Treatment.

Science.gov (United States)

Hatcher, Stacy Ellen; Waubant, Emmanuelle; Nourbakhsh, Bardia; Crabtree-Hartman, Elizabeth; Graves, Jennifer S

2016-07-01

The appropriate sequencing of agents with strong immune system effects has become increasingly important. Transitions require careful balance between safety and protection against relapse. The cases presented herein highlight that rebound events after ceasing fingolimod treatment may happen even with short washout periods (4 weeks) and may perpetuate despite steroid treatment or the immediate use of fast-acting immune therapies, such as rituximab. To describe rebound syndrome in patients with multiple sclerosis (MS) after cessation of fingolimod treatment. Clinical and demographic data were extracted from electronic medical records from the University of California, San Francisco, Multiple Sclerosis Center from January 2014 to December 2015. Magnetic resonance images were reviewed by MS neurologists (J.S.G., E.W., B.N., and E.C.H.). Rebound syndrome was defined as new severe neurological symptoms after ceasing fingolimod treatment, with the development of multiple new or enhancing lesions exceeding baseline activity. We reviewed the PubMed database from January 2010 to December 2015 for similar cases of severe disease reactivation after ceasing fingolimod treatment using search terms fingolimod and either rebound or reactivation. Participants were included if they stopped receiving fingolimod between January 2014 and December 2015. Five patients were identified who experienced rebound after ceasing fingolimod treatment. Each patient received treatment with oral fingolimod for various durations. Occurrence of rebound after ceasing fingolimod treatment. The mean (SD) age of the 5 female patients presented in this case series was 35.2 (6.4) years. Of the 46 patients that stopped fingolimod treatment within the 2-year period, 5 (10.9%) experienced severe relapse 4 to 16 weeks after ceasing fingolimod treatment. Despite varying prior severity of relapsing-remitting course, all participants experienced unexpectedly severe clinical relapses accompanied by drastic

Glacial rebound and crustal stress in Finland

International Nuclear Information System (INIS)

Lambeck, K.; Purcell, A.

2003-11-01

The last ice age of Fennoscandinavia continues to have geological repercussions across Finland despite the last ice having retreated almost 10,000 years ago: land uplift, shoreline retreat, and the stress state of the crust continues to evolve. This report focusses on the glacial rebound signals for Finland and the Gulf of Bothnia and explores the consequences of the ongoing deformation. The rebound signals include the geological evidence as well as instrumental observations: the tide gauge and lake-level measurements of the past century, the changes in geodetic levels recorded in the repeat levelling surveys of the region and the direct measurement of crustal deformation (radial and horizontal) using high-precision space-geodesy measurements. These signals provide constraints on the Earth's rheology, its elasticity and viscosity, and the glacial history of the region. Once observationally constrained, the rebound models are used to predict both the ongoing evolution of shorelines and the changing state of stress within the crust. This report covers: (i) A review of glacial rebound modelling for Scandinavia (Sections 2 and 3). (ii) Review of observational evidence relating to sea-level change and crustal rebound (Section 4). (iii) New earth and ice-sheet model results from the inversion of the geological evidence for sea-level change, including models of shoreline evolution (Sections 5 and 6). (iv) Earth-model results from the inversion of the geodetic evidence for sea-level change (Section 7). (v) Development of crustal stress models for past and present stress states (Section 8). (vi) Conclusions and recommendations (Section 9). Specific conclusions reached pertain to: (i) Thickness of ice cover over Scandinavia since the Last Glacial Maximum, particularly for the Lateglacial period. (ii) Sea-level change and shoreline evolution for the Baltic area since the time the region became ice-free for the last time. (iii) The predicted rates of present-day crustal

Rebound effect of improved energy efficiency for different energy types: A general equilibrium analysis for China

International Nuclear Information System (INIS)

Lu, Yingying; Liu, Yu; Zhou, Meifang

2017-01-01

This paper explores the rebound effect of different energy types in China based on a static computable general equilibrium model. A one-off 5% energy efficiency improvement is imposed on five different types of energy, respectively, in all the 135 production sectors in China. The rebound effect is measured both on the production level and on the economy-wide level for each type of energy. The results show that improving energy efficiency of using electricity has the largest positive impact on GDP among the five energy types. Inter-fuel substitutability does not affect the macroeconomic results significantly, but long-run impact is usually greater than the short-run impact. For the exports-oriented sectors, those that are capital-intensive get big negative shock in the short run while those that are labour-intensive get hurt in the long run. There is no “backfire” effect; however, improving efficiency of using electricity can cause negative rebound, which implies that improving the energy efficiency of using electricity might be a good policy choice under China's current energy structure. In general, macro-level rebound is larger than production-level rebound. Primary energy goods show larger rebound effect than secondary energy goods. In addition, the paper points out that the policy makers in China should look at the rebound effect in the long term rather than in the short term. The energy efficiency policy would be a good and effective policy choice for energy conservation in China when it still has small inter-fuel substitution. - Highlights: • Primary energy goods show larger rebound effect than secondary energy goods. • Improving efficiency of using electricity can cause negative rebound. • The energy efficiency policy would be an effective policy choice for China. • Policy-makers should consider the rebound effect in the longer term.

Reform of refined oil product pricing mechanism and energy rebound effect for passenger transportation in China

International Nuclear Information System (INIS)

Lin, Boqiang; Liu, Xia

2013-01-01

Improving energy efficiency is the primary method adopted by the Chinese government in an effort to achieve energy conservation target in the transport sector. However, the offsetting effect of energy rebound would greatly reduce its real energy-saving potentials. We set up a Linear Approximation of the Almost Ideal Demand System Model (LA-AIDS model) to estimate the rebound effect for passenger transportation in China. Real energy conservation effect of improving energy efficiency can also be obtained in the process. The result shows that the rebound effect is approximately 107.2%. This figure signifies the existence of ‘backfire effect’, indicating that efficiency improvement in practice does not always lead to energy-saving. We conclude that one important factor leading to the rebound effect, is the refined oil pricing mechanism. China's refined oil pricing mechanism has been subjected to criticism in recent years. The results of simulation analysis show that the rebound could be reduced to approximately 90.7% if the refined oil pricing mechanism is reformed. In this regard, we suggest further reforms in the current refined oil pricing mechanism. - Highlights: ► We set up the LA-AIDS model to estimate traffic service demand for urban residents. ► The size of the rebound effect for passenger transportation in China is evaluated. ► The rebound effect for passenger transportation in China is 107.2%. ► Reform of oil pricing could reduced the rebound to 90.7%. ► Reform of oil pricing might be an effective method for mitigating rebound effect

Rebound Effects in the Context of Developing Country Efficiency

Energy Technology Data Exchange (ETDEWEB)

de la Rue du Can, Stephane [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McNeil, Michael A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Leventis, Greg [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-08-30

Energy efficiency-related “rebound effects” usually refer to the tendency of most consumers to increase their use of energy services in response to efficiency measures that have reduced their energy costs. This phenomenon is one reason why energy efficiency policies often result in lower energy savings than engineering-based estimates predict. Rebound effects have been the subject of intense debate in the field of energy efficiency policy for many years.1 In the past, the focus of this debate has been on the perceived loss of the expected energy savings and related benefits resulting from the rebound effects. However, more recently, there has been a growing recognition that policymakers need to consider the health, economic and other non-energy benefits that often result from the increase in energy services represented by user “rebound effects”. This is especially true in developing countries where basic energy service demands—such as lighting, heating, cooling, and refrigeration of food—are often not being met. As economic conditions improve and household incomes increase, demand for increased energy services (such as space conditioning and appliances) tends to rise rapidly. Improving energy efficiency reduces the amount of energy needed to produce one unit of energy service output (for example an hour of cooling at 21°C delivered for X vs Y kWh). Greater efficiency therefore often enables more rapid increased in energy services (and sometimes access), expanding the amount of services that can be provided by a fixed amount (or cost) of energy.

Energy productivity improvements and the rebound effect: An overview of the state of knowledge

International Nuclear Information System (INIS)

Dimitropoulos, John

2007-01-01

The 'rebound effect' from more efficient use of energy has been well investigated, with plenty of evidence suggesting that the 'direct' rebound effect is relatively small for most energy services-typically less than 30%. However, the same conclusion may not apply to 'indirect' and 'economy-wide' rebound effects. Here, several authors suggest that improved energy efficiency may increase energy consumption in the medium to long term, a view that undermines the rationale for energy efficiency as an instrument of climate-related energy policy and has been ardently debated. One of the main reasons behind the debate is the lack of a rigorous theoretical framework that can describe the mechanisms and consequences of the rebound effect at the macro-economic level. Proponents of the rebound effect point to 'suggestive' evidence from a variety of areas including economic history, econometric measurements of productivity and macro-economic modelling. This evidence base is relatively small, highly technical, lacks transparency, rests upon contested theoretical assumptions and is inconclusive. This paper provides an accessible summary of the state of knowledge on this issue and shows how separate areas of research can provide relevant insights: namely neoclassical models of economic growth, computable general equilibrium (CGE) modelling and alternative models for policy evaluation. The paper provides a synopsis of how each approach may be used to explain, model and estimate the macro-economic rebound effect, criticisms that have been suggested against each, and explanations for diversity in quantitative estimates. Conclusions suggest that the importance of the macro-economic rebound effect should not be underestimated

Estimating the rebound effect in US manufacturing energy consumption

International Nuclear Information System (INIS)

Bentzen, Jan

2004-01-01

The energy price shocks of the 1970s are usually assumed to have increased the search for new energy saving technologies where eventual gains in energy efficiencies will reduce the real per unit price of energy services and hence, the consumption of energy will rise and partially offset the initial reduction in the usage of energy sources. This is the 'rebound effect', which is estimated for the US manufacturing sector using time series data applying the dynamic OLS method (DOLS). When allowing for asymmetric price effects the rebound effect is found to be approximately 24% for the US manufacturing sector

Using latent variable approach to estimate China's economy-wide energy rebound effect over 1954–2010

International Nuclear Information System (INIS)

Shao, Shuai; Huang, Tao; Yang, Lili

2014-01-01

The energy rebound effect has been a significant issue in China, which is undergoing economic transition, since it reflects the effectiveness of energy-saving policy relying on improved energy efficiency. Based on the IPAT equation and Brookes' explanation of the rebound effect, this paper develops an alternative estimation model of the rebound effect. By using the estimation model and latent variable approach, which is achieved through a time-varying coefficient state space model, we estimate China's economy-wide energy rebound effect over 1954–2010. The results show that the rebound effect evidently exists in China as a result of the annual average of 39.73% over 1954–2010. Before and after the implementation of China's reform and opening-up policy in 1978, the rebound effects are 47.24% and 37.32%, with a strong fluctuation and a circuitously downward trend, respectively, indicating that a stable political environment and the development of market economy system facilitate the effectiveness of energy-saving policy. Although the energy-saving effect of improving energy efficiency has been partly realised, there remains a large energy-saving potential in China. - Highlights: • We present an improved estimation methodology of economy-wide energy rebound effect. • We use the latent variable approach to estimate China's economy-wide rebound effect. • The rebound exists in China and varies before and after reform and opening-up. • After 1978, the average rebound is 37.32% with a circuitously downward trend. • Traditional Solow remainder method underestimates the rebound in most cases

The Microeconomic Theory of the Rebound Effect and Its Welfare Implications

OpenAIRE

Nathan W. Chan; Kenneth Gillingham

2015-01-01

Economists have long noted that improving energy efficiency could lead to a rebound effect, reducing or possibly even eliminating the energy savings from the efficiency improvement. This paper develops a generalized model to highlight features of the theory of the microeconomic rebound effect that are particularly relevant to empirical economists. We demonstrate when common elasticity identities used for empirical estimation are biased and how gross complement and substitute relationships gov...

Energy efficiency and rebound effects - Development, extent and containment; Energie-Effizienz und Reboundeffekte: Entstehung, Ausmass, Eindaemmung - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Haan, P. de

2009-07-15

In this final report published for the Swiss Federal Office of Energy (SFOE), the Institute for Environmental Decisions at the Swiss Federal Institute of Technology ETH in Zuerich examines so-called rebound effects. New, energy-efficient products that, in terms of energy-consumption, are cheaper to operate can lead to increased demand - the so-called rebound effect. The article deals with direct and indirect rebound effects and their origins as seen from the economical, socio-psychological and regulatory points of view. The results of empirical research on their magnitude are discussed and examples are quoted. Possible mental rebound effects are discussed, as are possible ways to inhibit such rebound effects.

Biological therapies (immunomodulatory drugs), worsening of psoriasis and rebound effect: new evidence of similitude.

Science.gov (United States)

Teixeira, Marcus Zulian

2016-11-01

Employing the secondary action or adaptative reaction of the organism as therapeutic response, homeopathy uses the treatment by similitude (similia similibus curentur) administering to sick individuals the medicines that caused similar symptoms in healthy individuals. Such homeostatic or paradoxical reaction of the organism is scientifically explained through the rebound effect of drugs, which cause worsening of symptoms after withdrawal of several palliative treatments. Despite promoting an improvement in psoriasis at the beginning of the treatment, modern biological therapies provoke worsening of the psoriasis (rebound psoriasis) after discontinuation of drugs. Exploratory qualitative review of the literature on the occurrence of the rebound effect with the use of immunomodulatory drugs [T-cell modulating agents and tumor necrosis factor (TNF) inhibitors drugs] in the treatment of psoriasis. Several researches indicate the rebound effect as the mechanism of worsening of psoriasis with the use of efalizumab causing the suspension of its marketing authorization in 2009, in view of some severe cases. Other studies also have demonstrated the occurrence of rebound psoriasis with the use of alefacept, etanercept and infliximab. As well as studied in other classes of drugs, the rebound effect of biologic agents supports the principle of similitude (primary action of the drugs followed by secondary action and opposite of the organism). Copyright © 2016 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Warfarin Poisoning with Delayed Rebound Toxicity.

Science.gov (United States)

Berling, Ingrid; Mostafa, Ahmed; Grice, Jeffrey E; Roberts, Michael S; Isbister, Geoffrey K

2017-02-01

Intentional poisoning with warfarin is not the same as over-anticoagulation, for which guidelines exist. The coagulopathy resulting from a warfarin overdose is reversed with vitamin K 1 , the dose and timing of which is often guided by experience with the management of over-anticoagulation with warfarin therapy, rather than acute overdose. We report a case of a 50-year-old man who ingested an unknown amount of his warfarin, venlafaxine, and paracetamol. He presented with an international normalized ratio (INR) of 2.5, which steadily increased over 24 h to 7, despite receiving an initial 1 mg of vitamin K 1 . He was then treated with 5 mg vitamin K 1 , and once the INR returned to 4.5, 40 h post ingestion, he was discharged home. He was also treated with a full course of acetylcysteine for the paracetamol overdose. The following day his INR rebounded to 8.5 and he suffered a spontaneous epistaxis requiring readmission; he was treated with low titrated doses of vitamin K 1 . The warfarin concentration was 74.6 μg/mL 26 h post ingestion and decreased to 3.7 μg/mL over 72 h. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Our case highlights the risk of a rebound elevated INR even 3 days after acute warfarin overdose despite treatment with vitamin K 1 . Understanding the pharmacokinetics of vitamin K 1 in comparison with warfarin, repeat INR testing, and continued treatment with oral vitamin K 1 may help avoid complications of rebound coagulopathy in warfarin overdose. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Atmospheric signals produced by cavity rebound

International Nuclear Information System (INIS)

Jones, E.M.; App, F.N.; Whitaker, R.W.

1993-01-01

An analysis of the atmospheric acoustic signals produced by a class of low-yield tests conducted just below the base of the alluvial cover in Yucca Flat of the Nevada Test Site (NTS), has revealed a clear manifestation of an elastic, cavity rebound signal. We use modeling as the basis for understanding the observed phenomena

Technological progress and sustainable development. What about the rebound effect?

International Nuclear Information System (INIS)

Binswanger, M.

2001-01-01

Sustainability concepts that rest on the idea of resource- or energy-efficiency improvements due to technological progress tend to overestimate the potential saving effects because they frequently ignore the behavioral responses evoked by technological improvements. Efficiency improvements also affect the demand for resources and energy, and often an increase in efficiency by 1% will cause a reduction in resource use that is far below 1% or, sometimes, it can even cause an increase in resource use. This phenomenon is commonly labeled the rebound effect, which is well-known among energy economists, but never attracted much attention in ecological economics. The paper starts with the traditional neoclassical analysis of the rebound effect in a partial equilibrium framework that concentrates on the demand of one particular energy service such as mobility or room temperature. It also provides an overview of some of the main empirical studies based on this model that mostly confirm the existence of the rebound effect, but are controversial about its actual importance. However, we have to go beyond the neoclassical single-service model in order to take care of the variety of possible feedback affecting energy use. The paper presents two important expansions of the single-service model in order to show the potential relevance of the rebound effect to ecological economics. First, it is shown that in a multi-services model it proves to be difficult to make general statements about the relevance of the rebound effect. In this case, the overall effect of an increase in energy efficiency on total energy use depends on the on the assumptions about the substitutability between the services considered and the direction of the income effect. Second, the paper also tries to take care of the fact that changes in resource use or energy use are frequently just 'side-effects' of other forms of technological progress. Especially technological change of a time-saving nature can have a

Evidence of direct and indirect rebound effect in households in EU-27 countries

International Nuclear Information System (INIS)

Freire-González, Jaume

2017-01-01

This research estimates the direct and indirect rebound effect of energy efficiency in households for the EU-27 countries (the first twenty-seven Member States of the European Union). A hybrid methodology that combines econometric estimates, environmental extended input-output analysis and re-spending models has been developed. Although most of the economies present values below 100%, there are seven countries situated above this critical threshold. By weighting individual estimates by GDP, an average value for the overall EU-27 economy has been found between 73.62% and 81.16%. These results suggest that the energy policy at the European level should be rethought if efficiency measures pursue reducing energy consumption and tackling climate change. - Highlights: • Empirical evidence of direct and indirect rebound effect is provided for EU-27. • Most economies have a rebound effect below the threshold of 100% (20 of them). • Additional energy efficiency measures are needed even with low direct rebounds.

Evaluating the direct and indirect rebound effects in household energy consumption behavior: A case study of Beijing

International Nuclear Information System (INIS)

Yu, Biying; Zhang, Junyi; Fujiwara, Akimasa

2013-01-01

This paper examines whether increases in energy efficiency of major household items cause additional short-run utilization of these end uses and other end uses for households in Beijing. An integrated model is first developed by combining a Logit model and a resource allocation model, where the former represents the choice of end-use ownership and the latter describes the end-use usage. The rebound effects are finally obtained from calculating the own- and cross-elasticities based on the prediction. The empirical results show that for refrigerators, electric fans, gas showers, TVs, and PCs, no evident rebound occurs; while for air conditioners, clothes washers, microwave ovens, and cars, either a direct rebound effect or an indirect rebound effect exists significantly. The respective average upper bound of direct rebound effects for them are 60.76%, 106.81%, 100.79%, and 33.61%, suggesting a possibility of backfire for the clothes washers and microwave ovens, while the respective upper bound of total rebound effects are 88.95%, 100.36%, 626.58%, and 31.61%. Furthermore, increasing the efficiency of air conditioners and cars can definitely reduce the total household energy consumption during the use phase. - Highlights: ► Evaluate the direct and indirect rebound effects for household energy consumption. ► Provide an evidence for rebound effect for the developing countries. ► Build an integrated model jointly representing end-use ownership and usage behavior. ► Significant rebound effects are found only for ACs, microwave ovens, washers and cars. ► Applicable policies for reducing residents' energy consumption in Beijing are given

The effectiveness of energy efficiency improvement in a developing country: Rebound effect of residential electricity use in South Korea

International Nuclear Information System (INIS)

Jin, Sang-Hyeon

2007-01-01

The government of South Korea considers an energy efficiency improvement policy an effective economic measure for climate change like many other governments. But it is unaware of any 'rebound effect', the unexpected result of energy efficiency improvement. So the rebound effect of residential electricity use in South Korea was estimated using two different scales in this paper. At the macro level, the rebound effect was estimated indirectly by using price elasticity, and at the micro level, the rebound effect of individual home appliances was estimated directly by using a non-linear relationship between energy efficiency and energy use. At the macro level, the long- and short-term results of rebound effect were estimated at 30% and 38%, respectively. Also at the micro level, the rebound effect of air conditioners was 57-70%; while refrigerators showed only a composite of rebound and income effects. Finally, there was no backfire effect, and efficiency improvement brought energy reduction. In conclusion, these suggest that rebound effect is an important factor that the government of South Korea must consider when planning its energy efficiency improvement policy. (author)

The rebound effect on road freight transport: Empirical evidence from Portugal

International Nuclear Information System (INIS)

Matos, Fernando J.F.; Silva, Francisco J.F.

2011-01-01

Because a large proportion of total operating costs for transportation companies goes towards energy, a reduction in energy operating costs, brought about by an increase in fleet fuel efficiency, or an increase in operational efficiency, results in a change in the relative cost of road freight transportation. This fact could result in an increase in the demand for such services. If this is true, the result would be an increase in total fuel consumption. Consequently, that part of the energy savings obtained through the increased energy efficiency would be lost. The existence of a 'Rebound Effect' is especially important in the road freight transportation sector and is crucial for the definition of a national energy policy. In this study, data from the road freight transportation sector in Portugal for the years of 1987 through 2006 was analyzed. It was determined that an increase in energy efficiency did not cause a backfire, but did cause a total direct rebound effect of 24.1%. In addition, fleet operators were more inclined to adopt operational efficiencies than technological fuel efficiencies as a means of increasing the total operational efficiency. - Research highlights: → We estimate a direct rebound effect for road freight transportation in Portugal. → The functional form chosen was a log-log model and the estimation method used was the two stage least squares model. → Increasing energy efficiency by 1% results in a reduction of 0.759% in energy consumption (a direct rebound effect of about 24.1%). → Estimates of reduced fuel consumption without considering the direct rebound effect may be overestimated by about 0.87 million liters of diesel per year for each percentage point increase in energy efficiency.

Revisiting Rebound Effects from Material Resource Use. Indications for Germany Considering Social Heterogeneity

Directory of Open Access Journals (Sweden)

Johannes Buhl

2014-02-01

Full Text Available In contrast to the original investigation by William Stanley Jevons, compensations of energy savings due to improved energy efficiency are mostly analyzed by providing energy consumption or greenhouse gas emissions. In support of a sustainable resource management, this paper analyzes so-called rebound effects based on resource use. Material flows and associated expenditures by households allow for calculating resource intensities and marginal propensities to consume. Marginal propensities to consume are estimated from data of the German Socio-Economic Panel (SOEP in order to account for indirect rebound effects for food, housing and mobility. Resource intensities are estimated in terms of total material requirements per household final consumption expenditures along the Classification of Individual Consumption according to Purpose (COICOP. Eventually, rebound effects are indicated on the basis of published saving scenarios in resource and energy demand for Germany. In sum, compensations due to rebound effects are lowest for food while the highest compensations are induced for mobility. This is foremost the result of a relatively high resource intensity of food and a relatively low resource intensity in mobility. Findings are provided by giving various propensity scenarios in order to cope with income differences in Germany. The author concludes that policies on resource conservation need to reconsider rebound effects under the aspect of social heterogeneity.

Brain prolactin is involved in stress-induced REM sleep rebound.

Science.gov (United States)

Machado, Ricardo Borges; Rocha, Murilo Ramos; Suchecki, Deborah

2017-03-01

REM sleep rebound is a common behavioural response to some stressors and represents an adaptive coping strategy. Animals submitted to multiple, intermittent, footshock stress (FS) sessions during 96h of REM sleep deprivation (REMSD) display increased REM sleep rebound (when compared to the only REMSD ones, without FS), which is correlated to high plasma prolactin levels. To investigate whether brain prolactin plays a role in stress-induced REM sleep rebound two experiments were carried out. In experiment 1, rats were either not sleep-deprived (NSD) or submitted to 96h of REMSD associated or not to FS and brains were evaluated for PRL immunoreactivity (PRL-ir) and determination of PRL concentrations in the lateral hypothalamus and dorsal raphe nucleus. In experiment 2, rats were implanted with cannulas in the dorsal raphe nucleus for prolactin infusion and were sleep-recorded. REMSD associated with FS increased PRL-ir and content in the lateral hypothalamus and all manipulations increased prolactin content in the dorsal raphe nucleus compared to the NSD group. Prolactin infusion in the dorsal raphe nucleus increased the time and length of REM sleep episodes 3h after the infusion until the end of the light phase of the day cycle. Based on these results we concluded that brain prolactin is a major mediator of stress-induced REMS. The effect of PRL infusion in the dorsal raphe nucleus is discussed in light of the existence of a bidirectional relationship between this hormone and serotonin as regulators of stress-induced REM sleep rebound. Copyright © 2016 Elsevier Inc. All rights reserved.

Measuring the Rebound Effect with Micro Data

DEFF Research Database (Denmark)

de Borger, Bruno; Mulalic, Ismir; Rouwendal, Jan

2015-01-01

the ‘conventional’ formulation in which only fuel cost per kilometre matters. Second, the selection equation confirms that higher fuel prices induce households to switch car. Third, the results suggest the presence of a rebound effect that is on the lower end of the estimates available in the literature...

Interactive football training based on rebounders with hit position sensing and audio/light feedback

DEFF Research Database (Denmark)

Jensen, Mads Møller; Grønbæk, Kaj; Rasmussen, Majken Kirkegård

A Danish football club has established a (24/7/365) football training facility, where the authors developed an interactive training installation (http://vimeo.com/28446312). The training installation consist of a 12*12 m square with 4 M­Station Pro rebounders equipped with sensors that enable hit...... position sensing. The rebounders are equipped with loudspeakers and lights being used to call for the ball. Here we discuss one game “Pass ­and ­Turn”, which is meant to train speed in controlling a returned ball, reaction to a call for the ball and turning to hit rebounders to the left, right, behind...

Energy rebound and economic growth: A review of the main issues and research needs

International Nuclear Information System (INIS)

Madlener, R.; Alcott, B.

2009-01-01

Contrary to conventional wisdom, more efficient use of energy may actually through rebound effects lead to greater instead of less total consumption of energy-or at least to no diminution of energy consumption. If so, energy efficiency strategies may serve goals of raising economic growth and affluence, but as an environmental or energy policy strategy could backfire, leading to more resource use in absolute terms rather than less. This, in turn, could in the long run hamper economic growth, for instance if resource scarcity crowds out technical change. The hypothesis that rebound is greater than unity ('backfire') predicts the observed real-world correlation between rising energy consumption and rising efficiency of energy services, however difficult it may be to define a precise holistic metric for the latter. The opposing hypothesis, i.e. that rebound is less than unity and that energy efficiency increases therefore result in less energy consumption than before, requires on the other hand strong forces that do account for the empirically observed economic growth. This paper summarises some of the discussions around the rebound effect, puts it into perspective to economic growth, and provides some insights at the end that can guide future empirical research on the rebound topic

Rebound hyperbilirubinaemia in neonates admitted to Mofid ...

African Journals Online (AJOL)

term neonates without a positive Coombs test were included, and only 1 patient was readmitted with rebound hyperbilirubinaemia. (this was thought to be due to breastmilk jaundice). Our ndings are therefore similar to those of Del Vecchio et al.,[8] who reported that 1 in 48 newborns required readmission for phototherapy.

Measuring impact rebound with photography

International Nuclear Information System (INIS)

Sumali, Hartono

2010-01-01

To study the rebound of a sphere colliding against a flat wall, a test setup was developed where the sphere is suspended with strings as a pendulum, elevated, and gravity-released to impact the wall. The motion of the sphere was recorded with a highspeed camera and traced with an image-processing program. From the speed of the sphere before and after each collision, the coefficient of restitution was computed, and shown to be a function of impact speed as predicted analytically.

The measurement of intraocular pressure over positive soft contact lenses by rebound tonometry

Directory of Open Access Journals (Sweden)

Fabrizio Zeri

2016-07-01

Conclusions: Rebound tonometry over positive hydrogel CLs leads to a certain degree of IOP underestimation. This result did not change for the two positive lenses used in the experiment, despite their large difference in power and therefore in lens thickness. Optometrists should bear this in mind when measuring IOP with the rebound tonometer over plus power contact lenses.

MD Simulation on Collision Behavior Between Nano-Scale TiO₂ Particles During Vacuum Cold Spraying.

Science.gov (United States)

Yao, Hai-Long; Yang, Guan-Jun; Li, Chang-Jiu

2018-04-01

Particle collision behavior influences significantly inter-nano particle bonding formation during the nano-ceramic coating deposition by vacuum cold spraying (or aerosol deposition method). In order to illuminate the collision behavior between nano-scale ceramic particles, molecular dynamic simulation was applied to explore impact process between nano-scale TiO2 particles through controlling impact velocities. Results show that the recoil efficiency of the nano-scale TiO2 particle is decreased with the increase of the impact velocity. Nano-scale TiO2 particle exhibits localized plastic deformation during collision at low velocities, while it is intensively deformed by collision at high velocities. This intensive deformation promotes the nano-particle adhesion rather than rebounding off. A relationship between the adhesion energy and the rebound energy is established for the bonding formation of the nano-scale TiO2 particle. The adhesion energy required to the bonding formation between nano-scale ceramic particles can be produced by high velocity collision.

Postoperative rebound of antiblood type antibodies and antibody-mediated rejection after ABO-incompatible living-related kidney transplantation.

Science.gov (United States)

Ishida, Hideki; Kondo, Tsunenori; Shimizu, Tomokazu; Nozaki, Taiji; Tanabe, Kazunari

2015-03-01

The purpose of this study is to examine whether postoperative antiblood type antibody rebound is attributed to kidney allograft rejection in ABO blood type-incompatible (ABO-I) living-related kidney transplantation (KTx). A total of 191 ABO-I recipients who received ABO-I living-related KTx between 2001 and 2013 were divided into two groups: Group 1 consisted of low rebound [(≦1:32), N = 170] and Group 2 consisted of high rebound [(≧1:64), N = 21], according to the levels of the rebounded antiblood type antibodies within 1 year after transplantation. No prophylactic treatment for rejection was administered for elevated antiblood type antibodies, regardless of the levels of the rebounded antibodies. Within 1 year after transplantation, T-cell-mediated rejection was observed in 13 of 170 recipients (13/170, 8%) in Group 1 and in 2 of 21 recipients (2/21, 10%) in Group 2 (Groups 1 vs. 2, P = 0.432). Antibody-mediated rejection was observed in 15 of 170 recipients (15/170, 9%) and 2 of 21 recipients (2/21, 10%) in Groups 1 and 2, respectively (P = 0.898). In this study, we found no correlation between the postoperative antiblood type antibody rebound and the incidence of acute rejection. We concluded that no treatment is necessary for rebounded antiblood type antibodies. © 2014 Steunstichting ESOT.

The measurement of intraocular pressure over positive soft contact lenses by rebound tonometry.

Science.gov (United States)

Zeri, Fabrizio; De Cusatis, Mario; Lupelli, Luigi; Swann, Peter Graham

2016-01-01

To investigate if the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over disposable hydrogel (etafilcon A) contact lenses (CL) is affected by the positive power of the CLs. The experimental group comprised 26 subjects, (8 male, 18 female). IOP measurements were undertaken on the subjects' right eyes in random order using a Rebound Tonometer (ICare). The CLs had powers of +2.00D and +6.00D. Measurements were taken over each contact lens and also before and after the CLs had been worn. The IOP measure obtained with both CLs was significantly lower compared to the value without CLs (t test; p<0.001) but no significant difference was found between the two powers of CLs. Rebound tonometry over positive hydrogel CLs leads to a certain degree of IOP underestimation. This result did not change for the two positive lenses used in the experiment, despite their large difference in power and therefore in lens thickness. Optometrists should bear this in mind when measuring IOP with the rebound tonometer over plus power contact lenses. Copyright © 2016 The Authors. Published by Elsevier Espana.. All rights reserved.

Ankle brace attenuates the medial-lateral ground reaction force during basketball rebound jump

Directory of Open Access Journals (Sweden)

Alex Castro

Full Text Available ABSTRACT Introduction: The jump landing is the leading cause for ankle injuries in basketball. It has been shown that the use of ankle brace is effective to prevent these injuries by increasing the mechanical stability of the ankle at the initial contact of the foot with the ground. Objective: To investigate the effects of ankle brace on the ground reaction force (GRF during the simulation of a basketball rebound jump. Method: Eleven young male basketball players randomly carried out a simulated basketball rebound jump under two conditions, with and without ankle brace (lace-up. Dynamic parameters of vertical GRF (take-off and landing vertical peaks, time to take-off and landing vertical peaks, take-off impulse peak, impulse at 50 milliseconds of landing, and jump height and medial-lateral (take-off and landing medial-lateral peaks, and time to reach medial-lateral peaks at take-off and landing were recorded by force platform during rebound jumps in each tested condition. The comparisons between the tested conditions were performed by paired t test (P0.05. Conclusion: The use of ankle brace during basketball rebound jumps attenuates the magnitude of medial-lateral GRF on the landing phase, without changing the vertical GRF. This finding indicates that the use of brace increases the medial-lateral mechanical protection by decreasing the shear force exerted on the athlete’s body without change the application of propulsive forces in the take-off and the impact absorption quality in the landing during the basketball rebound jump.

ostglacial rebound from VLBI Geodesy: On Establishing Vertical Reference

Science.gov (United States)

Argus, Donald .

1996-01-01

I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan, 1995] and predictions from postglacial rebound predictions [Peltier, 1995].

Do Methodological Choices in Environmental Modeling Bias Rebound Effects? A Case Study on Electric Cars.

Science.gov (United States)

Font Vivanco, David; Tukker, Arnold; Kemp, René

2016-10-18

Improvements in resource efficiency often underperform because of rebound effects. Calculations of the size of rebound effects are subject to various types of bias, among which methodological choices have received particular attention. Modellers have primarily focused on choices related to changes in demand, however, choices related to modeling the environmental burdens from such changes have received less attention. In this study, we analyze choices in the environmental assessment methods (life cycle assessment (LCA) and hybrid LCA) and environmental input-output databases (E3IOT, Exiobase and WIOD) used as a source of bias. The analysis is done for a case study on battery electric and hydrogen cars in Europe. The results describe moderate rebound effects for both technologies in the short term. Additionally, long-run scenarios are calculated by simulating the total cost of ownership, which describe notable rebound effect sizes-from 26 to 59% and from 18 to 28%, respectively, depending on the methodological choices-with favorable economic conditions. Relevant sources of bias are found to be related to incomplete background systems, technology assumptions and sectorial aggregation. These findings highlight the importance of the method setup and of sensitivity analyses of choices related to environmental modeling in rebound effect assessments.

Putting the brakes on prejudice rebound effects: An ironic effect of disparagement humor.

Science.gov (United States)

Ford, Thomas E; Teeter, Sabrina R; Richardson, Kyle; Woodzicka, Julie A

2017-01-01

When people high in prejudice censor prejudice in one setting, they can experience a prejudice rebound effect-subsequently responding with more prejudice than otherwise. Disparagement humor fosters the release rather than suppression of prejudice. Thus, two experiments tested the hypothesis that exposure to disparagement humor attenuates rebound effects. Participants suppressed prejudice by writing fewer anti-gay thoughts about same-sex adoption (Experiment 1) or by reporting greater support for same-sex civil rights (Experiment 2) when expecting to share their responses with others (non-prejudice norm condition) but not if others first exchanged anti-gay jokes (prejudice norm condition). High-prejudice participants then exhibited prejudice rebound in the non-prejudice norm condition only. They rated a gay man more stereotypically (Experiment 1) and allocated greater budget cuts to a gay student organization (Experiment 2) in the non-prejudice norm condition.

Become Involved with Someone Who Is on the Rebound?: How Fast Should You Run?

Science.gov (United States)

Knox, David; Zusman, Marty E.

2009-01-01

Analysis of survey data from 1002 undergraduates at a large southeastern university revealed differences between the 535 or 53.4% who had become involved (while on the rebound from a previous love relationship) in a new relationship compared to 316 or 31.5% who had not become involved in a new relationship while on the rebound. A profile of the…

The remarkable environmental rebound effect of electric cars: a microeconomic approach.

Science.gov (United States)

Font Vivanco, David; Freire-González, Jaume; Kemp, René; van der Voet, Ester

2014-10-21

This article presents a stepwise, refined, and practical analytical framework to model the microeconomic environmental rebound effect (ERE) stemming from cost differences of electric cars in terms of changes in multiple life cycle environmental indicators. The analytical framework is based on marginal consumption analysis and hybrid life cycle assessment (LCA). The article makes a novel contribution through a reinterpretation of the traditional rebound effect and methodological refinements. It also provides novel empirical results about the ERE for plug-in hybrid electric (PHE), full-battery electric (FBE), and hydrogen fuel cell (HFC) cars for Europe. The ERE is found to have a remarkable impact on product-level environmental scores. For the PHE car, the ERE causes a marginal increase in demand and environmental pressures due to a small decrease in the cost of using this technology. For FBE and HFC cars, the high capital costs cause a noteworthy decrease in environmental pressures for some indicators (negative rebound effect). The results corroborate the concern over the high influence of cost differences for environmental assessment, and they prompt sustainable consumption policies to consider markets and prices as tools rather than as an immutable background.

Direct energy rebound effect for road passenger transport in China: A dynamic panel quantile regression approach

International Nuclear Information System (INIS)

Zhang, Yue-Jun; Peng, Hua-Rong; Liu, Zhao; Tan, Weiping

2015-01-01

The transport sector appears a main energy consumer in China and plays a significant role in energy conservation. Improving energy efficiency proves an effective way to reduce energy consumption in transport sector, whereas its effectiveness may be affected by the rebound effect. This paper proposes a dynamic panel quantile regression model to estimate the direct energy rebound effect for road passenger transport in the whole country, eastern, central and western China, respectively, based on the data of 30 provinces from 2003 to 2012. The empirical results reveal that, first of all, the direct rebound effect does exist for road passenger transport and on the whole country, the short-term and long-term direct rebound effects are 25.53% and 26.56% on average, respectively. Second, the direct rebound effect for road passenger transport in central and eastern China tends to decrease, increase and then decrease again, whereas that in western China decreases and then increases, with the increasing passenger kilometers. Finally, when implementing energy efficiency policy in road passenger transport sector, the effectiveness of energy conservation in western China proves much better than that in central China overall, while the effectiveness in central China is relatively better than that in eastern China. - Highlights: • The direct rebound effect (RE) for road passenger transport in China is estimated. • The direct RE in the whole country, eastern, central, and western China is analyzed. • The short and long-term direct REs are 25.53% and 26.56% within the sample period. • Western China has better energy-saving performance than central and eastern China.

Intraocular pressure measurement over soft contact lens by rebound tonometer: a comparative study.

Science.gov (United States)

Nacaroglu, Senay Asik; Un, Emine Seker; Ersoz, Mehmet Giray; Tasci, Yelda

2015-01-01

To evaluate the intraocular pressure (IOP) measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry (GAT). Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens (RTCL, RT respectively) and by GAT, as well as their central corneal thickness (CCT) by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman analysis. Mean IOP values measured by RTCL, RT and GAT were 15.68±3.7, 14.50±3.4 and 14.16±2.8 (Pcontact lens by rebound tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population.

Deep foundation rebound instrumentation at the Grand Gulf Nuclear Power Station

International Nuclear Information System (INIS)

Blendy, M.M.; Boisen, B.P.

1978-01-01

Removing an extensive amount of overburden can initiate adjustments in the foundation mass. Rebound adjustments induced by this removal include, in addition to elastic response, elements of visco-elastic and plastic response which have to be taken into account when the foundation is loaded by subsequent construction. The accurate measurement of foundation response can be important in the design and construction of deep foundations and can be essential in the construction of very deep foundations. In 1974, a large foundation excavation was undertaken for the two unit Grand Gulf Nuclear Station. Overburden removal ranged in depth from 65 feet in the turbine area to 110 feet in the containment area. Very long, rod-type Multiple Position Borehole Extensometers measured the rebound. The design of the extensometers, and the dimensions of the installed instruments, are discussed. Graphs are included which show the adjustments measured by each extensometer during the deepening of the excavation. The measured rebound for each transducer package of each extensometer is summarized. The data are compared to predicted values based on a mathematical model developed using laboratory test results and empirical methods. The resulting information forms part of the permanent record of construction for the nuclear power station

Design phase identification of high pile rebound soils : final report

Science.gov (United States)

2010-12-15

An engineering problem has occurred when installing displacement piles in certain soils. During driving, piles are rebounding excessively during each hammer blow, causing delay and as a result may not achieve the required design capacities. Piles dri...

Rotational Rebound Attacks on Reduced Skein

DEFF Research Database (Denmark)

Khovratovich, Dmitry; Nikolić, Ivica; Rechberger, Christian

2014-01-01

ciphers, including the new standard SHA-3 (Keccak). The rebound attack is a start-from-the-middle approach for finding differential paths and conforming pairs in byte-oriented designs like Substitution-Permutation networks and AES. We apply our new compositional attack to the reduced version of the hash...... number of rounds. We also use neutral bits and message modification methods from the practice of collision search in MD5 and SHA-1 hash functions. These methods push the rotational property through more rounds than previous analysis suggested, and eventually establish a distinguishing property...

Sound Rhythms Are Encoded by Postinhibitory Rebound Spiking in the Superior Paraolivary Nucleus

Science.gov (United States)

Felix, Richard A.; Fridberger, Anders; Leijon, Sara; Berrebi, Albert S.; Magnusson, Anna K.

2013-01-01

The superior paraolivary nucleus (SPON) is a prominent structure in the auditory brainstem. In contrast to the principal superior olivary nuclei with identified roles in processing binaural sound localization cues, the role of the SPON in hearing is not well understood. A combined in vitro and in vivo approach was used to investigate the cellular properties of SPON neurons in the mouse. Patch-clamp recordings in brain slices revealed that brief and well timed postinhibitory rebound spiking, generated by the interaction of two subthreshold-activated ion currents, is a hallmark of SPON neurons. The Ih current determines the timing of the rebound, whereas the T-type Ca2+ current boosts the rebound to spike threshold. This precisely timed rebound spiking provides a physiological explanation for the sensitivity of SPON neurons to sinusoidally amplitude-modulated (SAM) tones in vivo, where peaks in the sound envelope drive inhibitory inputs and SPON neurons fire action potentials during the waveform troughs. Consistent with this notion, SPON neurons display intrinsic tuning to frequency-modulated sinusoidal currents (1–15Hz) in vitro and discharge with strong synchrony to SAMs with modulation frequencies between 1 and 20 Hz in vivo. The results of this study suggest that the SPON is particularly well suited to encode rhythmic sound patterns. Such temporal periodicity information is likely important for detection of communication cues, such as the acoustic envelopes of animal vocalizations and speech signals. PMID:21880918

The Rebound Attack and Subspace Distinguishers: Application to Whirlpool

DEFF Research Database (Denmark)

Lamberger, Mario; Mendel, Florian; Schläffer, Martin

2015-01-01

We introduce the rebound attack as a variant of differential cryptanalysis on hash functions and apply it to the hash function Whirlpool, standardized by ISO/IEC. We give attacks on reduced variants of the 10-round Whirlpool hash function and compression function. Our results are collisions for 5...

Calculations of environmental benefits from using geothermal energy must include the rebound effect

DEFF Research Database (Denmark)

Atlason, Reynir Smari; Unnthorsson, Runar

2017-01-01

and energy production patterns are simulated using data from countries with similar environmental conditions but do not use geothermal or hydropower to the same extent as Iceland. Because of the rapid shift towards renewable energy and exclusion of external energy provision, the country is considered......When considering the environmental benefits from converting to renewable energy sources, the rebound effect is often omitted. In this study, the aim is to investigate greenhouse gas emission reduction inclusive of the rebound effect. We use Iceland as a case study where alternative consumption...

Rate on the rebound of films, strategic design and results

International Nuclear Information System (INIS)

Guibelalde, E.; Fernandez, J.M.; Ramirez, R.; Canevaro, R.; Vano, E.

1998-01-01

The present work pretends to identify the diagnostic tests of greatest rate on the rebound and to analyze their causes comparing them with the reference values obtained in the University Hospital 'San Carlos' study in 1993. Equally is looking for contributing with criterions and strategies for the implantation of a responsible system of information caption. The control of the rate on rebound of radiographic plates is fundamental for the quality control programs feedback. The results emitted by this study confirm the utility to the advantage of this type of global indicators for the quality control programs and contribute reducing collective doses, since the improvement of medical diagnostic and diminishing the operation costs of the inputs utilized. It is emphasized the importance what had to introduce at the personnel which participate in the system to obtain fitted results. (Author)

The rebound effect of resource efficiency; Het reboundeffect bij resource efficiency

Energy Technology Data Exchange (ETDEWEB)

Oosterhuis, F.; Bouma, J. [Instituut voor Milieuvraagstukken IVM, Vrije Universiteit, Amsterdam (Netherlands); Hanemaaijer, A. [Planbureau voor de Leefomgeving PBL, Den Haag (Netherlands)

2013-12-15

As a result of efficient use of natural resources production and use of goods and services can be made cheaper, which increases demand. However, that might partially offset savings in energy and other natural resources. This so-called 'rebound effect' can not be ignored. It is therefore worthwhile to keep that in formulating 'resource efficiency' policy [Dutch] Door efficienter om te gaan met natuurlijke hulpbronnen kunnen de productie en het gebruik van goederen en diensten goedkoper worden, waardoor de vraag ernaar toeneemt. Dat kan de besparingen op energie en andere natuurlijke hulpbronnen deels weer teniet doen. Dit 'rebound-effect' is niet verwaarloosbaar. Het is zinvol om hier bij beleid gericht op 'resource efficiency' rekening mee te houden.

Evaluation of monkey intraocular pressure by rebound tonometer

Science.gov (United States)

Yu, Wenhan; Cao, Guiqun; Qiu, Jinghua; Ma, Jia; Li, Ni; Yu, Man; Yan, Naihong; Chen, Lei; Pang, Iok-Hou

2009-01-01

Purpose To evaluate the usefulness of the TonoVet™ rebound tonometer in measuring intraocular pressure (IOP) of monkeys. Methods The accuracy of the TonoVet™ rebound tonometer was determined in cannulated eyes of anesthetized rhesus monkeys where IOP was controlled by adjusting the height of a connected perfusate reservoir. To assess the applicability of the equipment through in vivo studies, the diurnal fluctuation of IOP and effects of IOP-lowering compounds were evaluated in monkeys. Results IOP readings generated by the TonoVet™ tonometer correlated very well with the actual pressure in the cannulated monkey eye. The linear correlation had a slope of 0.922±0.014 (mean±SEM, n=4), a y-intercept of 3.04±0.61, and a correlation coefficient of r2=0.97. Using this method, diurnal IOP fluctuation of the rhesus monkey was demonstrated. The tonometer was also able to detect IOP changes induced by pharmacologically active compounds. A single topical ocular instillation (15 μg) of the rho kinase inhibitor, H1152, produced a 5–6 mmHg reduction (pmonkey eye. PMID:19898690

Free fall characteristics of particle clusters in a vertical pipe

International Nuclear Information System (INIS)

Nakashima, K; Johno, Y; Shigematsu, T

2009-01-01

When powder forms a weak interaction particle cluster in a gas-solid flow, the rate of fall of the cluster exceeds the terminal velocity of the individual particles (Slack, 1963; Marzocchella et al., 1991). However, the relationship between the unsteady characteristics of the free-fall of the particle cluster and the geometric condition of the experiment is not clear. We performed a simple experiment in which powder of a certain mass falls in a vertical pipe. When the powder falls in the vertical pipe, the distribution length of the powder expands, and the particle volume fraction is dense in the lower part, and is thin in the upper part. The fall velocity of the lower edge of the powder cluster and the flow rate of air generated by the powder fall were measured. We obtained the following results. The relative velocity of free-fall of the particle cluster has no relation to the individual particle diameters. The characteristic of a particle cluster exists unless the cluster has very high void fraction.

Test plan for the FY 1997 rebound study at the carbon tetrachloride soil vapor extraction site

International Nuclear Information System (INIS)

Rohay, V.J.; Tranbarger, R.K.

1996-11-01

This test plan describes the strategy and field measurements designed to evaluate the potential rebound of carbon tetrachloride vapor concentrations following cessation of soil vapor extraction (SVE) operations at the 200-ZP-2 Operable Unit in the 200 West Area of the Hanford Site. Soil vapor extraction was initiated in February 1992 as the preferred remedial alternative of the Carbon Tetrachloride Expedited Response Action for removal of carbon tetrachloride from the unsaturated zone beneath the primary carbon tetrachloride disposal sites. The magnitude, extent, and rate of rebound in carbon tetrachloride vapor concentrations will help determine the availability of additional carbon tetrachloride for removal using SVE. At the conclusion of the field measurements, a report will be completed to evaluate the results of the rebound study

A new approach to measuring the rebound effect associated to energy efficiency improvements: An application to the US residential energy demand

International Nuclear Information System (INIS)

Orea, Luis; Llorca, Manuel; Filippini, Massimo

2015-01-01

This paper brings attention to the fact that the energy demand frontier model introduced by Filippini and Hunt (2011, 2012) is closely connected to the measurement of the so-called rebound effect associated with improvements in energy efficiency. In particular, we show that their model implicitly imposes a zero rebound effect, which contradicts most of the available empirical evidence on this issue. We relax this restrictive assumption through the modelling of a rebound-effect function that mitigates or intensifies the effect of an efficiency improvement on energy consumption. We illustrate our model with an empirical application that aims to estimate a US frontier residential aggregate energy demand function using panel data for 48 states over the period 1995 to 2011. Average values of the rebound effect in the range of 56–80% are found. Therefore, policymakers should be aware that most of the expected energy reduction from efficiency improvements may not be achieved. - Highlights: • A new approach to measuring rebound effects in energy consumption is presented. • We illustrate our proposal with an application to US residential energy demand. • Relatively large rebound effects in the range of 56–80% are found. • Energy-inefficient states tend to exhibit low rebound effects. • We identify states where energy-saving policies should be more effective

Negative rebound and disinvestment effects in response to an improvement in energy efficiency in the UK economy

International Nuclear Information System (INIS)

Turner, Karen

2009-01-01

This paper uses a computable general equilibrium (CGE) framework to investigate the conditions under which rebound effects may occur in response to increases in energy efficiency in the UK national economy. Previous work for the UK has suggested that rebound effects will occur even where key elasticities of substitution in production are set close to zero. The research reported in this paper involves carrying out a systematic sensitivity analysis, where relative price sensitivity is gradually introduced into the system, focusing specifically on elasticities of substitution in production and trade parameters, in order to determine conditions under which rebound effects become a likely outcome. The main result is that, while there is positive pressure for rebound effects even where (direct and indirect) demands for energy are very price inelastic, this may be partially or wholly offset by negative income, competitiveness and disinvestment effects, which also occur in response to falling energy prices. The occurrence of disinvestment effects is of particular interest. These occur where falling energy prices reduce profitability in domestic energy supply sectors, leading to a contraction in capital stock in these sectors, which may in turn lead to rebound effects that are smaller in the long run than in the short run, a result that runs contrary to the predictions of previous theoretical work in this area.

Negative rebound and disinvestment effects in response to an improvement in energy efficiency in the UK economy

Energy Technology Data Exchange (ETDEWEB)

Turner, Karen [Department of Economics, University of Strathclyde, Sir William Duncan Building, 130 Rottenrow, Glasgow G4 0GE (United Kingdom)

2009-09-15

This paper uses a computable general equilibrium (CGE) framework to investigate the conditions under which rebound effects may occur in response to increases in energy efficiency in the UK national economy. Previous work for the UK has suggested that rebound effects will occur even where key elasticities of substitution in production are set close to zero. The research reported in this paper involves carrying out a systematic sensitivity analysis, where relative price sensitivity is gradually introduced into the system, focusing specifically on elasticities of substitution in production and trade parameters, in order to determine conditions under which rebound effects become a likely outcome. The main result is that, while there is positive pressure for rebound effects even where (direct and indirect) demands for energy are very price inelastic, this may be partially or wholly offset by negative income, competitiveness and disinvestment effects, which also occur in response to falling energy prices. The occurrence of disinvestment effects is of particular interest. These occur where falling energy prices reduce profitability in domestic energy supply sectors, leading to a contraction in capital stock in these sectors, which may in turn lead to rebound effects that are smaller in the long run than in the short run, a result that runs contrary to the predictions of previous theoretical work in this area. (author)

Pilot Evaluation Study of the Life Skills Program REBOUND

Directory of Open Access Journals (Sweden)

Henrik Jungaberle

2015-11-01

Full Text Available The main aim of the study is pilot evaluation of the life skills program REBOUND in a school context focusing on substance use, risk perception, and knowledge about psychoactive substances ( n IG + CG = 723 students in five schools and 46 classes, Mage = 14.8, range 14-18 for the total sample and in the subgroups gender, age, and school type. Main goal of the study is collecting evidence for program optimization. A controlled study was carried out with repeated measurement before and after the intervention (4-6 months. Multilevel analyses, ANCOVA, and logistic regression analyses were applied to measure the effects. Overall, significantly lower incidence rates of drunkenness (odds ratio [OR] = .55; p = .033, improved knowledge about psychoactive substances (p = .006, lower personal (p = .013 and general tobacco risk perception among users (p = .002, and lower general tobacco (p = .018 and cannabis (p = .000 risk perception in non-users were found in the total intervention group. In subgroups, significantly lower rates for the incidence of drunkenness can be shown for males (p = .008 and for younger participants (p = .004. Students at academic high school (German Gymnasium showed a decrease in 30-day prevalence for alcohol (p = .017 and cannabis (p = .014, and they improved in their knowledge about psychoactive substances (p = .000. In vocational high school classes (German Realschule, there was an increase in the relative alcohol risk perception of the students (p = .019. REBOUND contributes to a controlled use of alcohol and increases knowledge about psychoactive substances. REBOUND has various effects on the examined subgroups age, gender, and school type: Males, younger students, and students in academic high school benefitted more from the course regarding consumption-related criteria. We suggest a program optimization specific to school form and age, inclusion of a tobacco intervention, and the use of more gender-segregated interventions.

A quantile regression analysis of the rebound effect: Evidence from the 2009 National Household Transportation Survey in the United States

International Nuclear Information System (INIS)

Su Qing

2012-01-01

This paper applies quantile regression method to measure the rebound effect and differentiate it with respect to demand for mobility using the 2009 National Household Transportation Survey (NHTS). The quantile regression results indicate that the rebound effect varies with the distribution of vehicle miles traveled (VMT), ranging between 0.11 and 0.19. Road network density and population density also play an important role in determining travel demand. Regression results indicate that travelers living in areas with higher road network density travel more miles although this positive impact consistently declines along the VMT distribution. Travelers living in areas with population density of at most 3000 persons per square miles travel more miles than those living in higher density areas. The quantile regression results also indicate that the impact of income is positive but declines consistently along the VMT distribution. - Highlights: ► This paper examines the magnitude of rebound effect using the 2009 National Household Transportation Survey data. ► Quantile regression method is applied to capture the variation of the rebound effect given the heterogeneous travelers. ► The regression results indicate that the rebound effect varies with VMT distribution. ► The estimated rebound effect fluctuates between 0.11 and 0.19.

Postglacial Rebound from VLBI Geodesy: On Establishing Vertical Reference

Science.gov (United States)

Argus, Donald F.

1996-01-01

Difficulty in establishing a reference frame fixed to the earth's interior complicates the measurement of the vertical (radial) motions of the surface. I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan] and predictions from postglacial rebound predictions [Peltier]. The optimal translation of the geocenter is 1.7mm/year toward 36degN, 111degE when determined from the motions of 10 VLBI sites. This translation gives a better fit of observations to predictions than does the VLBI reference frame used by Ma and Ryan, but the improvement is statistically insignificant. The root mean square of differences decreases 20% to 0.73 mm/yr and the correlation coefficient increases from 0.76 to 0.87. Postglacial rebound is evident in the uplift of points in Sweden and Ontario that were beneath the ancient ice sheets of Fennoscandia and Canada, and in the subsidence of points in the northeastern U.S., Germany, and Alaska that were around the periphery of the ancient ice sheets.

Autologous Stem Cell Transplantation Disrupts Adaptive Immune Responses during Rebound Simian/Human Immunodeficiency Virus Viremia.

Science.gov (United States)

Reeves, Daniel B; Peterson, Christopher W; Kiem, Hans-Peter; Schiffer, Joshua T

2017-07-01

Primary HIV-1 infection induces a virus-specific adaptive/cytolytic immune response that impacts the plasma viral load set point and the rate of progression to AIDS. Combination antiretroviral therapy (cART) suppresses plasma viremia to undetectable levels that rebound upon cART treatment interruption. Following cART withdrawal, the memory component of the virus-specific adaptive immune response may improve viral control compared to primary infection. Here, using primary infection and treatment interruption data from macaques infected with simian/human immunodeficiency virus (SHIV), we observe a lower peak viral load but an unchanged viral set point during viral rebound. The addition of an autologous stem cell transplant before cART withdrawal alters viral dynamics: we found a higher rebound set point but similar peak viral loads compared to the primary infection. Mathematical modeling of the data that accounts for fundamental immune parameters achieves excellent fit to heterogeneous viral loads. Analysis of model output suggests that the rapid memory immune response following treatment interruption does not ultimately lead to better viral containment. Transplantation decreases the durability of the adaptive immune response following cART withdrawal and viral rebound. Our model's results highlight the impact of the endogenous adaptive immune response during primary SHIV infection. Moreover, because we capture adaptive immune memory and the impact of transplantation, this model will provide insight into further studies of cure strategies inspired by the Berlin patient. IMPORTANCE HIV patients who interrupt combination antiretroviral therapy (cART) eventually experience viral rebound, the return of viral loads to pretreatment levels. However, the "Berlin patient" remained free of HIV rebound over a decade after stopping cART. His cure is attributed to leukemia treatment that included an HIV-resistant stem cell transplant. Inspired by this case, we studied the impact

Real-Time Predictions of Reservoir Size and Rebound Time during Antiretroviral Therapy Interruption Trials for HIV.

Directory of Open Access Journals (Sweden)

Alison L Hill

2016-04-01

Full Text Available Monitoring the efficacy of novel reservoir-reducing treatments for HIV is challenging. The limited ability to sample and quantify latent infection means that supervised antiretroviral therapy (ART interruption studies are generally required. Here we introduce a set of mathematical and statistical modeling tools to aid in the design and interpretation of ART-interruption trials. We show how the likely size of the remaining reservoir can be updated in real-time as patients continue off treatment, by combining the output of laboratory assays with insights from models of reservoir dynamics and rebound. We design an optimal schedule for viral load sampling during interruption, whereby the frequency of follow-up can be decreased as patients continue off ART without rebound. While this scheme can minimize costs when the chance of rebound between visits is low, we find that the reservoir will be almost completely reseeded before rebound is detected unless sampling occurs at least every two weeks and the most sensitive viral load assays are used. We use simulated data to predict the clinical trial size needed to estimate treatment effects in the face of highly variable patient outcomes and imperfect reservoir assays. Our findings suggest that large numbers of patients-between 40 and 150-will be necessary to reliably estimate the reservoir-reducing potential of a new therapy and to compare this across interventions. As an example, we apply these methods to the two "Boston patients", recipients of allogeneic hematopoietic stem cell transplants who experienced large reductions in latent infection and underwent ART-interruption. We argue that the timing of viral rebound was not particularly surprising given the information available before treatment cessation. Additionally, we show how other clinical data can be used to estimate the relative contribution that remaining HIV+ cells in the recipient versus newly infected cells from the donor made to the

Improved non-invasive method for aerosol particle charge measurement employing in-line digital holography

Science.gov (United States)

Tripathi, Anjan Kumar

Electrically charged particles are found in a wide range of applications ranging from electrostatic powder coating, mineral processing, and powder handling to rain-producing cloud formation in atmospheric turbulent flows. In turbulent flows, particle dynamics is influenced by the electric force due to particle charge generation. Quantifying particle charges in such systems will help in better predicting and controlling particle clustering, relative motion, collision, and growth. However, there is a lack of noninvasive techniques to measure particle charges. Recently, a non-invasive method for particle charge measurement using in-line Digital Holographic Particle Tracking Velocimetry (DHPTV) technique was developed in our lab, where charged particles to be measured were introduced to a uniform electric field, and their movement towards the oppositely charged electrode was deemed proportional to the amount of charge on the particles (Fan Yang, 2014 [1]). However, inherent speckle noise associated with reconstructed images was not adequately removed and therefore particle tracking data was contaminated. Furthermore, particle charge calculation based on particle deflection velocity neglected the particle drag force and rebound effect of the highly charged particles from the electrodes. We improved upon the existing particle charge measurement method by: 1) hologram post processing, 2) taking drag force into account in charge calculation, 3) considering rebound effect. The improved method was first fine-tuned through a calibration experiment. The complete method was then applied to two different experiments, namely conduction charging and enclosed fan-driven turbulence chamber, to measure particle charges. In all three experiments conducted, the particle charge was found to obey non-central t-location scale family of distribution. It was also noted that the charge distribution was insensitive to the change in voltage applied between the electrodes. The range of voltage

The Particle Number Emission Characteristics of the Diesel Engine with a Catalytic Diesel Particle Filter

Directory of Open Access Journals (Sweden)

Li Jia Qiang

2016-01-01

Full Text Available Due to their adverse health effects and their abundance in urban areas, diesel exhaust ultrafine particles caused by the aftertreatment devices have been of great concern in the past years. An experiment of particles number emissions was carried out on a high-pressure, common rail diesel engine with catalytic diesel particle filter (CDPF to investigate the impact of CDPF on the number emission characteristics of particles. The results indicated that the conversion rates of CDPF is over 97%. The size distributions of particles are bimodal lognormal distributions downstream CDPF at 1400 r/min and 2300 r/min. CDPF has a lower conversion rates on the nucleation mode particles. The geometric number mean diameters of particles downstream CDPF is smaller than that upstream CDPF.

How does speed affect the rebound effect in car travel? Conceptual issues explored in case study of 900 Formula 1 Grand Prix speed trials

International Nuclear Information System (INIS)

Galvin, Ray

2017-01-01

The “rebound effect” occurs when reductions in energy consumption following energy efficiency increases are lower than engineering estimates. In cars this happens when drivers increase their distance travelled or average speed, as a behavioural response to cheaper travel. Rebound effects due to increased distance travelled have been extensively studied, but only one existing study attempts to quantify rebound effects due to increased average speed. This paper builds on that study, using a much larger empirical base and offering more generalised and more widely applicable mathematical modelling. It uses data from 30 Formula 1 Grand Prix time trial sessions of 10 vehicles doing 3 trials each, in 2014 and 2015. The heavily regulated Formula 1 regime, with its precisely measured data, provides a highly controlled framework for developing mathematics of average speed rebounds. The study thereby shows how speed and distance rebounds can be coherently combined in road vehicle travel to produce total rebound figures. It then shows how even small increases in average speed can nullify all the energy savings that are expected from energy efficiency increases. It also raises critical questions on the adequacy of proposed new road vehicle fuel efficiency testing procedures. - Highlights: • Rebound effects in car travel have been well studied for distance but not speed. • But speed rebound effects reduce fuel savings from energy efficiency upgrades. • A mathematical model is developed for dealing with average speed rebounds. • This model is tested with precise data from 900 Formula 1 Grand Prix time trials. • It is shown how speed and distance rebounds can be combined in everyday car travel.

Avoiding Rebound through a Steady-State Economy

DEFF Research Database (Denmark)

Nørgaard, Jørgen

2008-01-01

The debate on the rebound effect as presented in most chapters in this book is based upon experience from the past more than visions of the future. The analyses are dominated by conventional economic theory, which implicitly assumes insatiable demand for energy services. Material consumption...... social and cultural traditions may provide prerequisites for such a society, including public attitudes towards low birth rates, equity, consumption and work. Although this chapter presents a Nordic perspective, the options and trends described are relevant worldwide. It is assumed that absolute...

Modifying the rebound: It depends! Explaining mobility behavior on the basis of the German socio-economic panel

International Nuclear Information System (INIS)

Matiaske, Wenzel; Menges, Roland; Spiess, Martin

2012-01-01

We address the empirical question of the extent to which higher fuel efficiency of cars affects additional travel and the way this behavioral aspect is modified by additional variables. The data set used to estimate a theoretical model of the rebound effect covers two panel waves, 1998 and 2003, taken from the German Socio-Economic Panel (SOEP). To take full advantage of the information in the data available, and to avoid problems due to possible selection effects, we estimated an unbalanced two-wave random effects panel model. Our results suggest that in line with the rebound hypothesis, car efficiency has a negative effect on the kilometers driven. That is, the lower the fuel consumption, the greater the distance driven. However, contrasting recent empirical literature about the rebound effect in the transportation sector, this seems to be true only for cars with a consumption of more than roughly 8 l per 100 km. In addition, we find a positive diesel effect, which implies that owning a diesel engine car is positively correlated with the distance driven. Both effects can be interpreted as support for the rebound hypothesis, although not in a simple linear way. Moreover, it can be shown that some “soft” variables such as certain attitudes towards the environment tend to amplify this non-linear rebound effect. - Research Highlights: ► We address the empirical question of the extent to which higher fuel efficiency of cars affects additional travel. ► The data set covers two panel waves, 1998 and 2003, taken from the German Socio-Economic Panel (SOEP). We estimate an unbalanced two-wave random effects panel model. ► Contrasting recent empirical literature, this seems to be true only for cars with a consumption of more than roughly 8 l per 100 km.► In addition, we find a positive diesel effect: Owning a diesel engine car has a positive effect on the distance driven. Both effects support the rebound hypothesis, although not in a simple linear way.► It can

Rebound Deformity After Growth Modulation in Patients With Coronal Plane Angular Deformities About the Knee: Who Gets It and How Much?

Science.gov (United States)

Leveille, Lise A; Razi, Ozan; Johnston, Charles E

2017-05-18

With observed success and increased popularity of growth modulation techniques, there has been a trend toward use in progressively younger patients. Younger age at growth modulation increases the likelihood of complete deformity correction and need for implant removal before skeletal maturity introducing the risk of rebound deformity. The purpose of this study was to quantify magnitude and identify risk factors for rebound deformity after growth modulation. We performed a retrospective review of all patients undergoing growth modulation with a tension band plate for coronal plane deformity about the knee with subsequent implant removal. Exclusion criteria included completion epiphysiodesis or osteotomy at implant removal, ongoing growth modulation, and modulation, before implant removal, and at final follow-up. In total, 67 limbs in 45 patients met the inclusion criteria. Mean age at growth modulation was 9.8 years (range, 3.4 to 15.4 y) and mean age at implant removal was 11.4 years (range, 5.3 to 16.4 y). Mean change in HKA after implant removal was 6.9 degrees (range, 0 to 23 degrees). In total, 52% of patients had >5 degrees rebound and 30% had >10 degrees rebound in HKA after implant removal. Females below 10 years and males below 12 years at time of growth modulation had greater mean change in HKA after implant removal compared with older patients (8.4 vs. 4.7 degrees, P=0.012). Patients with initial deformity >20 degrees had an increased frequency of rebound >10 degrees compared with patients with less severe initial deformity (78% vs. 22%, P=0.002). Rebound deformity after growth modulation is common. Growth modulation at a young age and large initial deformity increases risk of rebound. However, rebound does not occur in all at risk patients, therefore, we recommend against routine overcorrection. Level IV-retrospective study.

Numerical simulation on void bubble dynamics using moving particle semi-implicit method

International Nuclear Information System (INIS)

Tian Wenxi; Ishiwatari, Yuki; Ikejiri, Satoshi; Yamakawa, Masanori; Oka, Yoshiaki

2009-01-01

In present study, the collapse of void bubble in liquid has been simulated using moving particle semi-implicit (MPS) code. The liquid is described using moving particles and the bubble-liquid interface was set to be vacuum pressure boundary without interfacial heat mass transfer. The topological shape of bubble can be traced according to the motion and location of interfacial particles. The time dependent bubble diameter, interfacial velocity and bubble collapse time were obtained under wide parametric range. The comparison with Rayleigh and Zababakhin's prediction showed a good agreement which validates the applicability and accuracy on MPS method in solving present momentum problems. The potential void induced water hammer pressure pulse was also evaluated which is instructive for further material erosion study. The bubble collapse with non-condensable gas has been further simulated and the rebound phenomenon was successfully captured which is similar with vapor-filled cavitation phenomenon. The present study exhibits some fundamental characteristics of void bubble hydrodynamics and it is also expected to be instructive for further applications of MPS method to complicated bubble dynamics problems.

Development of a particle method of characteristics (PMOC) for one-dimensional shock waves

Science.gov (United States)

Hwang, Y.-H.

2018-03-01

In the present study, a particle method of characteristics is put forward to simulate the evolution of one-dimensional shock waves in barotropic gaseous, closed-conduit, open-channel, and two-phase flows. All these flow phenomena can be described with the same set of governing equations. The proposed scheme is established based on the characteristic equations and formulated by assigning the computational particles to move along the characteristic curves. Both the right- and left-running characteristics are traced and represented by their associated computational particles. It inherits the computational merits from the conventional method of characteristics (MOC) and moving particle method, but without their individual deficiencies. In addition, special particles with dual states deduced to the enforcement of the Rankine-Hugoniot relation are deliberately imposed to emulate the shock structure. Numerical tests are carried out by solving some benchmark problems, and the computational results are compared with available analytical solutions. From the derivation procedure and obtained computational results, it is concluded that the proposed PMOC will be a useful tool to replicate one-dimensional shock waves.

Observations and Modeling of the Green Ocean Amazon 2014/15: Transmission Electron Microscopy Analysis of Aerosol Particles Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Buseck, Peter [Arizona State Univ., Tempe, AZ (United States)

2016-03-01

During two Intensive Operational Periods (IOP), we collected samples at 3-hour intervals for transmission electron microscopy analysis. The resulting transmission electron microscopy images and compositions were analyzed for the samples of interest. Further analysis will be done especially for the plume of interest. We found solid spherical organic particles from rebounded samples collected with Professor Scot Martin’s group (Harvard University). Approximately 30% of the rebounded particles at 95% relative humidity were spherical organic particles. Their sources and formation process are not known, but such spherical particles could be solid and will have heterogeneous chemical reactions. We observed many organic particles that are internally mixed with inorganic elements such as potassium and nitrogen. They are either homogeneously mixed or have inorganic cores with organic aerosol coatings. Samples collected from the Manaus, Brazil, pollution plume included many nano-size soot particles mixed with organic material and sulfate. Aerosol particles from clean periods included organic aerosol particles, sulfate, sea salt, dust, and primary biogenic aerosol particles. There was more dust, primary biogenic aerosol, and tar balls in samples taken during IOP1 than those taken during IOP2. Many dust particles were found between March 2 and 3.

­­Drought, water conservation, and water demand rebound in California

Science.gov (United States)

Gonzales, P.; Ajami, N.

2017-12-01

There is growing recognition that dynamic community values, preferences, and water use behaviors are important drivers of water demand in addition to external factors such as temperature and precipitation. Water demand drivers have been extensively studied, yet they have traditionally been applied to models that assume static conditions and usually do not account for potential societal changes in response to increased scarcity awareness. For example, following a period of sustained low demand such as during a drought, communities often increase water use during a hydrologically wet period, a phenomenon known as "rebounding" water use. Yet previous experiences show the extent of this rebound is not a straightforward function of policy and efficiency improvements, but may also reflect short-term or long-lasting change in community behavior, which are not easily captured by models that assume stationarity. In this study we explore cycles of decreased water demand during drought and subsequent water use rebound observed in California in recent decades. We have developed a novel dynamic system model for water demand in three diverse but interconnected service areas in the San Francisco Bay Area, exposing local trends of changing water use behaviors and long-term impacts on water demand since 1980 to the present. In this model, we apply the concept of social memory, defined as a community's inherited knowledge about hazardous events or degraded environmental conditions from past experiences. While this concept has been applied to further conceptual understanding of socio-hydrologic systems in response to hydrological extremes, to the best of our knowledge this the first study to incorporate social memory to model the water demand rebound phenomenon and to use such a model in the examination of changing dynamics validated by historical data. In addition, we take a closer look at water demand during the recent historic drought in California from 2012-16, and relate our

A study of the rebound effect on China's current energy conservation and emissions reduction: Measures and policy choices

International Nuclear Information System (INIS)

Lin, Boqiang; Yang, Fang; Liu, Xia

2013-01-01

Energy efficiency improvement leads to a reduction in the real cost of energy services per unit, thus bringing about an increase in the demand for energy services. Therefore, the potential energy savings and emission reduction from efficiency improvements might be offset, which is known as “the rebound effect”. This study disaggregates the effect into the direct and indirect effects based on the Slutsky Equation and finds that the rebound effect of Chinese urban households is approximately 22%. It is found that the indirect effect is stronger than the direct effect. These findings prove that the initial goals of the government on energy conservation and emission reduction could not be achieved by improving energy efficiency alone, but need to be supplemented with relevant energy pricing reforms. - Highlights: • This study disaggregates the effect into the direct and indirect effects. • The rebound effect of Chinese urban households is approximately 22%. • The indirect effect is stronger than the direct effect. • Energy pricing reform is needed to mitigate the rebound effect

Comparison of intraocular pressure measurement between rebound, non-contact and Goldmann applanation tonometry in treated glaucoma patients.

Science.gov (United States)

Vincent, Stephen J; Vincent, Roslyn A; Shields, David; Lee, Graham A

2012-01-01

To compare the intraocular pressure readings obtained with the iCare rebound tonometer and the 7CR non-contact tonometer with those measured by Goldmann applanation tonometry in treated glaucoma patients. A prospective, cross-sectional study was conducted in a private tertiary glaucoma clinic. One hundred nine (54 males : 55 females) patients including only eyes under medical treatment for glaucoma. Measurement by Goldmann applanation tonometry, iCare rebound tonometry and 7CR non-contact tonometry. Intraocular pressure. There were strong correlations between the intraocular pressure measurements obtained with Goldmann and both the rebound and non-contact tonometers (Spearman r-values ≥ 0.79, P tonometer. For the rebound tonometer, the mean intraocular pressure was slightly higher compared with the Goldmann applanation tonometer in the right eyes (P = 0.02), and similar in the left eyes (P = 0.93); however, these differences did not reach statistical significance. The Goldmann correlated measurements from the non-contact tonometer were lower than the average Goldmann reading for both right (P 0.01) eyes. The corneal compensated measurements from the non-contact tonometer were significantly higher compared with the other tonometers (P ≤ 0.001). The iCare rebound tonometer and the 7CR non-contact tonometer measure intraocular pressure in fundamentally different ways to the Goldmann applanation tonometer. The resulting intraocular pressure values vary between the instruments and will need to be considered when comparing clinical versus home acquired measurements. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

Physical and chemical characteristics of interplanetary dust particles

International Nuclear Information System (INIS)

Gruen, E.

1981-01-01

For the first time, the micrometeoroid experiment on board of Helios allowed the measurement of physical and chemical characteristics of interplanetary dust particles between 0.3AU and 1AU solar distance. During the first 10 orbits of Helios 1,235 impacts of micrometeoroids have been detected. 83 particles have been registered by the ecliptic sensor and 152 by the south sensor. Most of the particles detected by the ecliptic sensor had masses 10 -13 g -10 g and impacted the sensor from the apex direction. The particles observed by the south sensor had masses 10 -15 g -9 g and impacted the sensor from all directions with a slightly enhanced flux from solar direction. The average impact speed of particles with masses 10 -13 g -10 g was 15km/s. From 1AU to.3AU, the observed paritcle flux increased by a factor 5-10. The orbits of the registered particles are highly eccentric, e approx. >= 0.6, and some are hyperbolic. The mass spectra measured upon impact allow the classification of chondritic and iron-rich particles. Approx. 20% of the particles had low densities rho 3 . On 4 particles, a positive electric charge has been observed. (orig.) [de

Plasma HIV-1 RNA viral load rebound among people who inject drugs receiving antiretroviral therapy (ART) in a Canadian setting: an ethno-epidemiological study.

Science.gov (United States)

Small, Will; Milloy, M J; McNeil, Ryan; Maher, Lisa; Kerr, Thomas

2016-01-01

People who inject drugs (PWID) living with HIV often experience sub-optimal antiretroviral therapy (ART) treatment outcomes, including HIV plasma viral load (PVL) rebound. While previous studies have identified risk factors for PVL rebound among PWID, no study has examined the perspectives of PWID who have experienced PVL rebound episodes. We conducted an ethno-epidemiological study to investigate the circumstances surrounding the emergence of rebound episodes among PWID in Vancouver, BC, Canada. Comprehensive clinical records linked to a community-based prospective observational cohort of HIV-positive drug users were used to identify PWID who had recently experienced viral rebound. In-depth qualitative interviews with 16 male and 11 female participants explored participant perspectives regarding the emergence of viral rebound. A timeline depicting each participant's HIV viral load and adherence to ART was used to elicit discussion of circumstances surrounding viral rebound. Viral rebound episodes were shaped by interplay between various individual, social, and environmental factors that disrupted routines facilitating adherence. Structural-environmental influences resulting in non-adherence included housing transitions, changes in drug use patterns and intense drug scene involvement, and inadequate care for co-morbid health conditions. Social-environmental influences on ART adherence included poor interactions between care providers and patients producing non-adherence, and understandings of HIV treatment that fostered intentional treatment discontinuation. This study describes key pathways which led to rebound episodes among PWID receiving ART and illustrates how environmental forces may increase vulnerability for non-adherence leading to treatment failure. Our findings have potential to help inform interventions and supports that address social-structural forces that foster non-adherence among PWID.

Relationship of HIV Reservoir Characteristics with Immune Status and Viral Rebound Kinetics in an HIV Therapeutic Vaccine Study

Science.gov (United States)

Li, Jonathan Z.; Heisey, Andrea; Ahmed, Hayat; Wang, Hongying; Zheng, Lu; Carrington, Mary; Wrin, Terri; Schooley, Robert T.; Lederman, Michael M.; Kuritzkes, Daniel R.

2014-01-01

Objectives To evaluate the impact of therapeutic HIV vaccination on the HIV reservoir, and assess the relationship of the viral reservoir with HIV-specific immune status and viral rebound kinetics. Design Retrospective analysis of ACTG A5197, a randomized, placebo-controlled trial of a therapeutic rAd5 HIV-1 gag vaccine. Methods Participants received vaccine/placebo at weeks 0, 4, and 26 prior to a 16-week analytic treatment interruption (ATI) at week 38. Cell-associated HIV-1 RNA and DNA (CA-RNA and CA-DNA) and HIV-1 residual viremia (RV) were quantified at weeks 0, 8, and 38. HIV-specific CD4+/CD8+ activity were assessed by an intracellular cytokine staining assay. Results At study entry, CA-RNA and CA-DNA levels were correlated inversely with the numbers of HIV-specific CD4+ interferon-γ-producing cells (CA-RNA: r = −0.23, P=0.03 and CA-DNA: r = −0.28, P<0.01, N=93). Therapeutic HIV vaccination induced HIV-specific CD4+ activity, but did not significantly affect levels of CA-RNA or CA-DNA. Vaccine recipients with undetectable RV at week 8 had higher frequencies of HIV-specific CD4+ and CD8+ interferon-γ-producing cells (undetectable versus detectable RV: 277 versus 161 CD4+ cells/106 lymphocytes, P=0.03 and 1326 versus 669 CD8+ cells/106 lymphocytes, P=0.04). Pre-ATI CA-RNA and CA-DNA were associated with post-ATI plasma HIV set point (CA-RNA: r = 0.51, P<0.01 and CA-DNA: r = 0.47, P<0.01). Conclusions Vaccine-induced T-cell responses were associated with a modest transient effect on RV, but more potent immune responses and/or combination treatment with latency-reversing agents are needed to reduce the HIV reservoir. HIV reservoir measures may act as biomarkers of post-ATI viral rebound kinetics. PMID:25254301

Social and Structural Patterns of Drought-Related Water Conservation and Rebound

Science.gov (United States)

Gonzales, Patricia; Ajami, Newsha

2017-12-01

Water use practices and conservation are the result of complex sociotechnical interactions of political, economic, hydroclimatic, and social factors. While the drivers of water demand have been extensively studied, they have traditionally been applied to models that assume stationary relationships between these various factors, and usually do not account for potential societal changes in response to increased scarcity awareness. For example, following a period of sustained low demand such as during a drought, communities often increase water use during a hydrologically wet period, a phenomenon known as "rebounding" water use. Previous experiences show the extent of this rebound is not a straightforward function of policy and efficiency improvements, but may also reflect short-term or long-lasting change in community behavior, which are not easily captured by models that assume stationarity. In this work, we develop a system dynamics model to represent water demand as a function of both structural and social factors. We apply this model to the analysis of three diverse water utilities in the San Francisco Bay Area between 1980 and 2017, identifying drought response trends and drivers over time. Our model is consistent with empirical patterns and historical context of water use in California, and provides important insights on the rebound phenomenon that can be extended to other locations. This comparative assessment indicates that policies, public outreach, and better data availability have played a key role in raising public awareness of water scarcity, especially with the raise of the internet era in recent years.

Concrete density estimation by rebound hammer method

International Nuclear Information System (INIS)

Ismail, Mohamad Pauzi bin; Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri; Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin; Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin

2016-01-01

Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite

Quantifying the direct and indirect rebound effects for consumers as a response to energy-saving technologies in the EU-27

NARCIS (Netherlands)

Hu, J.; Poliakov, E.V.

2015-01-01

We estimate the rebound effect for residential space heating at the EU-27 level, which occurs when an improvement in energy efficiency results in additional energy consumption. Three types of rebound effects are distinguished, namely the direct effect, indirect effect and the embodied energy. We

Lock-and-key mechanisms of cerebellar memory recall based on rebound currents.

Science.gov (United States)

Wetmore, Daniel Z; Mukamel, Eran A; Schnitzer, Mark J

2008-10-01

A basic question for theories of learning and memory is whether neuronal plasticity suffices to guide proper memory recall. Alternatively, information processing that is additional to readout of stored memories might occur during recall. We formulate a "lock-and-key" hypothesis regarding cerebellum-dependent motor memory in which successful learning shapes neural activity to match a temporal filter that prevents expression of stored but inappropriate motor responses. Thus, neuronal plasticity by itself is necessary but not sufficient to modify motor behavior. We explored this idea through computational studies of two cerebellar behaviors and examined whether deep cerebellar and vestibular nuclei neurons can filter signals from Purkinje cells that would otherwise drive inappropriate motor responses. In eyeblink conditioning, reflex acquisition requires the conditioned stimulus (CS) to precede the unconditioned stimulus (US) by >100 ms. In our biophysical models of cerebellar nuclei neurons this requirement arises through the phenomenon of postinhibitory rebound depolarization and matches longstanding behavioral data on conditioned reflex timing and reliability. Although CS-US intervals100 ms. This bound reflects the minimum time for deinactivation of rebound currents such as T-type Ca2+. In vestibulo-ocular reflex adaptation, hyperpolarization-activated currents in vestibular nuclei neurons may underlie analogous dependence of adaptation magnitude on the timing of visual and vestibular stimuli. Thus, the proposed lock-and-key mechanisms link channel kinetics to recall performance and yield specific predictions of how perturbations to rebound depolarization affect motor expression.

A strategy for modeling ground water rebound in abandoned deep mine systems.

Science.gov (United States)

Adams, R; Younger, P L

2001-01-01

Discharges of polluted water from abandoned mines are a major cause of degradation of water resources worldwide. Pollution arises after abandoned workings flood up to surface level, by the process termed ground water rebound. As flow in large, open mine voids is often turbulent, standard techniques for modeling ground water flow (which assume laminar flow) are inappropriate for predicting ground water rebound. More physically realistic models are therefore desirable, yet these are often expensive to apply to all but the smallest of systems. An overall strategy for ground water rebound modeling is proposed, with models of decreasing complexity applied as the temporal and spatial scales of the systems under analysis increase. For relatively modest systems (area modeling approach has been developed, in which 3-D pipe networks (representing major mine roadways, etc.) are routed through a variably saturated, 3-D porous medium (representing the country rock). For systems extending more than 100 to 3000 km2, a semidistributed model (GRAM) has been developed, which conceptualizes extensively interconnected volumes of workings as ponds, which are connected to other ponds only at discrete overflow points, such as major inter-mine roadways, through which flow can be efficiently modeled using the Prandtl-Nikuradse pipe-flow formulation. At the very largest scales, simple water-balance calculations are probably as useful as any other approach, and a variety of proprietary codes may be used for the purpose.

Effect of flow characteristics on ultrafine particle emissions from range hoods.

Science.gov (United States)

Tseng, Li-Ching; Chen, Chih-Chieh

2013-08-01

In order to understand the physical mechanisms of the production of nanometer-sized particulate generated from cooking oils, the ventilation of kitchen hoods was studied by determining the particle concentration, particle size distribution, particle dimensions, and hood's flow characteristics under several cooking scenarios. This research varied the temperature of the frying operation on one cooking operation, with three kinds of commercial cooking oils including soybean oil, olive oil, and sunflower oil. The variations of particle concentration and size distributions with the elevated cooking oil temperatures were presented. The particle concentration increases as a function of temperature. For oil temperatures ranging between 180°C and 210°C, a 5°C increase in temperature increased the number concentration of ultrafine particles by 20-50%. The maximum concentration of ultrafine particles was found to be approximately 6 × 10(6) particles per cm(3) at 260°C. Flow visualization techniques and particle distribution measurement were performed for two types of hood designs, a wall-mounted range hood and an island hood, at a suction flow rate of 15 m(3) min(-1). The flow visualization results showed that different configurations of kitchen hoods induce different aerodynamic characteristics. By comparing the results of flow visualizations and nanoparticle measurements, it was found that the areas with large-scale turbulent vortices are more prone to dispersion of ultrafine particle leakage because of the complex interaction between the shear layers and the suction movement that results from turbulent dispersion. We conclude that the evolution of ultrafine particle concentration fluctuations is strongly affected by the location of the hood, which can alter the aerodynamic features. We suggest that there is a correlation between flow characteristics and amount of contaminant leakage. This provides a comprehensive strategy to evaluate the effectiveness of kitchen hoods

Measuring the rebound effect with micro data: A first difference approach

DEFF Research Database (Denmark)

De Borger, Bruno; Mulalic, Ismir; Rouwendal, Jan

2016-01-01

the 'conventional' formulation in which only fuel cost per kilometre matters. Second, the selection equation confirms that higher fuel prices induce households to switch car. Third, the results suggest the presence of a rebound effect that is on the lower end of the estimates available in the literature...

Ash formation and deposition in coal and biomass fired combustion systems: Progress and challenges in the field of ash particle sticking and rebound behavior

DEFF Research Database (Denmark)

Kleinhans, Ulrich; Wieland, Christoph; Frandsen, Flemming J.

2018-01-01

. The impaction of solid, molten or partially molten particles on surfaces is dependent on the particle and surface characteristics. For instance, a particulate deposit might capture incoming particles or be removed due to erosion, while a molten layer will collect all impacting particles, no matter...... if they are sticky or not. The main properties affecting the particle stickiness are the viscosity and surface tension for silicate-rich ashes. On the contrary, the stickiness of salt-rich ashes – typical for herbaceous biomass and wood- or waste-based fuels – is often described using the liquid melt fraction......, their required parameters are discussed and typical particle and surface properties found in combustion systems, are summarized. Eight different sticking criteria are implemented in a computational fluid dynamics code and computations are compared against measurements from an entrained flow reactor. Uniform...

Effect of limestone particle size on bone quality characteristics of ...

African Journals Online (AJOL)

A study was conducted to determine the effect of different limestone particle sizes in layer diets on bone quality characteristics at end-of-lay hens. Calcitic limestone (360 g Ca/kg DM) that is extensively used in commercial poultry diets was obtained from a specific South African source. Limestone particles were graded as ...

In situ real-time measurement of physical characteristics of airborne bacterial particles

Science.gov (United States)

Jung, Jae Hee; Lee, Jung Eun

2013-12-01

Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis.

Reliability of Lyapunov characteristic exponents computed by the two-particle method

Science.gov (United States)

Mei, Lijie; Huang, Li

2018-03-01

For highly complex problems, such as the post-Newtonian formulation of compact binaries, the two-particle method may be a better, or even the only, choice to compute the Lyapunov characteristic exponent (LCE). This method avoids the complex calculations of variational equations compared with the variational method. However, the two-particle method sometimes provides spurious estimates to LCEs. In this paper, we first analyze the equivalence in the definition of LCE between the variational and two-particle methods for Hamiltonian systems. Then, we develop a criterion to determine the reliability of LCEs computed by the two-particle method by considering the magnitude of the initial tangent (or separation) vector ξ0 (or δ0), renormalization time interval τ, machine precision ε, and global truncation error ɛT. The reliable Lyapunov characteristic indicators estimated by the two-particle method form a V-shaped region, which is restricted by d0, ε, and ɛT. Finally, the numerical experiments with the Hénon-Heiles system, the spinning compact binaries, and the post-Newtonian circular restricted three-body problem strongly support the theoretical results.

Regional energy rebound effect: The impact of economy-wide and sector level energy efficiency improvement in Georgia, USA

International Nuclear Information System (INIS)

Yu, Xuewei; Moreno-Cruz, Juan; Crittenden, John C.

2015-01-01

Rebound effect is defined as the lost part of ceteris paribus energy savings from improvements on energy efficiency. In this paper, we investigate economy-wide energy rebound effects by developing a computable general equilibrium (CGE) model for Georgia, USA. The model adopts a highly disaggregated sector profile and highlights the substitution possibilities between different energy sources in the production structure. These two features allow us to better characterize the change in energy use in face of an efficiency shock, and to explore in detail how a sector-level shock propagates throughout the economic structure to generate aggregate impacts. We find that with economy-wide energy efficiency improvement on the production side, economy-wide rebound is moderate. Energy price levels fall very slightly, yet sectors respond to these changing prices quite differently in terms of local production and demand. Energy efficiency improvements in particular sectors (epicenters) induce quite different economy-wide impacts. In general, we expect large rebound if the epicenter sector is an energy production sector, a direct upstream/downstream sector of energy production sectors, a transportation sector or a sector with high production elasticity. Our analysis offers valuable insights for policy makers aiming to achieve energy conservation through increasing energy efficiency. - Highlights: • We developed a CGE model to investigate economy-wide energy rebound in Georgia, USA. • The CGE model has detailed treatment for different energy inputs for production. • The model has a highly disaggregated sector profile helpful for policy making. • We compared the economy-wide impact shocks in different epicenter sectors. • We analyzed why epicenters generate dramatically different economy-wide impacts.

Influence of a mini-trampoline rebound exercise program on insulin resistance, lipid profile and central obesity in individuals with type 2 diabetes.

Science.gov (United States)

Nuhu, Jibril M; Maharaj, Sonill S

2018-04-01

Exercises are important as an adjuvant for managing diabetes but due to fatigue and time constraints, individuals with diabetes may not engage in them. Jumping on a mini-trampoline referred to as rebound exercise is an aerobic activity used for exercise training benefits but only little research is available on its effects in diabetes. The purpose of this study was to determine the effect of mini-trampoline rebound exercise on insulin resistance, lipid profile and central obesity in type 2 diabetics. Sixty non-insulin dependent type 2 diabetics (median age: 39.0 years, median body mass index: 25.2 kg/m2) recruited using convenience sampling were randomized to a rebound exercise group (N.=30) or a control group (N.=30). The control group read health magazines or watched television while the rebound exercise group jumped on a mini-trampoline at moderate intensity for 30 minutes three times per week for 12 weeks. Postrebound exercise, significant improvements in insulin resistance, lipid profile and waist circumference were noted when compared to the control (Ptrampoline rebound exercise is beneficial for individuals with type 2 diabetes and can serve as a useful exercise approach in the management of cardiovascular risk in diabetes.

Rebound coefficient of collisionless gas in a rigid vessel. A model of reflection of field-reversed configuration

International Nuclear Information System (INIS)

Takaku, Yuichi; Hamada, Shigeo

1996-01-01

A system of collisionless neutral gas contained in a rigid vessel is considered as a simple model of reflection of field-reversed configuration (FRC) plasma by a magnetic mirror. The rebound coefficient of the system is calculated as a function of the incident speed of the vessel normalized by the thermal velocity of the gas before reflection. The coefficient is compared with experimental data of FIX (Osaka U.) and FRX-C/T(Los Alamos N.L.). Agreement is good for this simple model. Interesting is that the rebound coefficient takes the smallest value (∼0.365) as the incident speed tends to zero and approaches unity as it tends to infinity. This behavior is reverse to that expected for a system with collision dominated fluid instead of collisionless gas. By examining the rebound coefficient, therefore, it could be successfully inferred whether the ion mean free path in each experiment was longer or shorter than the plasma length. (author)

Ultrasonic control of ceramic membrane fouling: Effect of particle characteristics.

Science.gov (United States)

Chen, Dong; Weavers, Linda K; Walker, Harold W

2006-02-01

In this study, the effect of particle characteristics on the ultrasonic control of membrane fouling was investigated. Ultrasound at 20 kHz was applied to a cross-flow filtration system with gamma-alumina membranes in the presence of colloidal silica particles. Experimental results indicated that particle concentration affected the ability of ultrasound to control membrane fouling, with less effective control of fouling at higher particle concentrations. Measurements of sound wave intensity and images of the cavitation region indicated that particles induced additional cavitation bubbles near the ultrasonic source, which resulted in less turbulence reaching the membrane surface and subsequently less effective control of fouling. When silica particles were modified to be hydrophobic, greater inducement of cavitation bubbles near the ultrasonic source occurred for a fixed concentration, also resulting in less effective control of fouling. Particle size influenced the cleaning ability of ultrasound, with better permeate recovery observed with larger particles. Particle size did not affect sound wave intensity, suggesting that the more effective control of fouling by large particles was due to greater lift and cross-flow drag forces on larger particles compared to smaller particles.

Rebound spiking in layer II medial entorhinal cortex stellate cells: Possible mechanism of grid cell function

Science.gov (United States)

Shay, Christopher F.; Ferrante, Michele; Chapman, G. William; Hasselmo, Michael E.

2015-01-01

Rebound spiking properties of medial entorhinal cortex (mEC) stellate cells induced by inhibition may underlie their functional properties in awake behaving rats, including the temporal phase separation of distinct grid cells and differences in grid cell firing properties. We investigated rebound spiking properties using whole cell patch recording in entorhinal slices, holding cells near spiking threshold and delivering sinusoidal inputs, superimposed with realistic inhibitory synaptic inputs to test the capacity of cells to selectively respond to specific phases of inhibitory input. Stellate cells showed a specific phase range of hyperpolarizing inputs that elicited spiking, but non-stellate cells did not show phase specificity. In both cell types, the phase range of spiking output occurred between the peak and subsequent descending zero crossing of the sinusoid. The phases of inhibitory inputs that induced spikes shifted earlier as the baseline sinusoid frequency increased, while spiking output shifted to later phases. Increases in magnitude of the inhibitory inputs shifted the spiking output to earlier phases. Pharmacological blockade of h-current abolished the phase selectivity of hyperpolarizing inputs eliciting spikes. A network computational model using cells possessing similar rebound properties as found in vitro produces spatially periodic firing properties resembling grid cell firing when a simulated animal moves along a linear track. These results suggest that the ability of mEC stellate cells to fire rebound spikes in response to a specific range of phases of inhibition could support complex attractor dynamics that provide completion and separation to maintain spiking activity of specific grid cell populations. PMID:26385258

Therapeutic use of the rebound effect of modern drugs: "New homeopathic medicines"

Directory of Open Access Journals (Sweden)

Marcus Zulian Teixeira

Full Text Available Summary The homeopathic treatment is based on the principle of therapeutic similitude, employing medicines that cause certain disorders to treat similar manifestations, stimulating a reaction of the organism against its own ailments. The occurrence of this secondary reaction of the organism, opposite in nature to the primary action of the medicines, is evidenced in the study of the rebound (paradoxical effect of several classes of modern drugs. In this work, in addition to substantiate the principle of similitude before the experimental and clinical pharmacology, we suggest a proposal to employ hundreds of conventional drugs according to homeopathic method, applying the therapeutic similitude between the adverse events of medicines and the clinical manifestations of patients. Describing existing lines of research and a specific method for the therapeutic use of the rebound effect of modern drugs (http://www.newhomeopathicmedicines.com, we hope to minimize prejudices related to the homeopathy and contribute to a broadening of the healing art.

Ethnicity predicts viral rebound after travel to the tropics in HIV-infected travelers to the tropics in the Swiss HIV Cohort Study.

Science.gov (United States)

Gebreselassie, H M; Kraus, D; Fux, C A; Haubitz, S; Scherrer, A; Hatz, C; Veit, O; Stoeckle, M; Fehr, J; de Lucia, S; Cavassini, M; Bernasconi, E; Schmid, P; Furrer, H; Staehelin, C

2017-09-01

The number of HIV-infected individuals from developed countries travelling to tropical and subtropical areas has increased as a result of the clinical and survival benefits of combination antiretroviral therapy. The aim of our study was to describe the traveler population in the SHCS and to determine the frequency of viral rebound in virologically suppressed individuals after a travel episode to the tropics compared to non-travelers. Swiss HIV Cohort Study participants with at least one follow-up visit between 1 January 1989 and 28 February 2015 were eligible for inclusion in the study. The primary outcome was the occurrence of viral rebound (viral load > 200 HIV-1 RNA copies/mL) after a travel episode compared with a nontravel episode in previously suppressed individuals (≤ 200 copies/mL). All virologically suppressed patients contributed multiple travel or nontravel episodes to the analysis. Logistic regression was performed including factors associated with viral rebound. We included 16 635 patients in the study, of whom 6084 (36.5%) had ever travelled to the tropics. Travel frequency increased over time, with travellers showing better HIV parameters than nontravellers [less advanced Centers for Disease Control and Prevention (CDC) stage and higher CD4 count nadir]. Viral rebound was seen in 477 (3.9%) of 12 265 travel episodes and in 5121 (4.5%) of 114 884 nontravel episodes [unadjusted odds ratio (OR) 0.87; 95% confidence interval (CI) 0.78-0.97]. Among these 477 post-travel viral rebounds, 115 had a resistance test performed and 51 (44%) of these showed new resistance mutations. Compared with European and North American patients, the odds for viral rebound were significantly lower in Southeast Asian (OR 0.67; 95% CI 0.51-0.88) and higher in sub-Saharan African (SSA) patients (OR 1.41; 95% CI 1.22-1.62). Travel further increased the odds of viral rebound in SSA patients (OR 2.00; 95% CI 1.53-2.61). Region of origin is the main risk factor for viral rebound

Rebound policy in the Paris Agreement: instrument comparison and climate-club revenue offsets

NARCIS (Netherlands)

van den Bergh, J.C.J.M.

2017-01-01

Rebound is given scant attention in both IPCC documents and UNFCCC climate summits, where climate agreements are negotiated. This article argues that without an international climate treaty, or with a soft treaty in the form of voluntary pledges, as characterizes the recent Paris climate agreement,

Characteristics of agglomerates of sodium oxide aerosol particles: Task 7, topical report

International Nuclear Information System (INIS)

Gieseke, J.A.; Reed, L.D.; Jordan, H.; Lee, K.W.

1977-01-01

Accurate macroscopic predictions of aerosol population behavior within enclosed containments are known to depend strongly upon the microscopic characteristics of the individual aerosols. Also, coagulation rates due to mechanisms which produce relative motions between particles within the suspended aerosol are known to depend upon the cross sectional areas of the individual particles. Hence, it has been the primary concern of this study to examine experimentally the microscopic characteristics of sodium oxide aerosols produced in air. The results of these measurements can now be incorporated into the various macroscopic aerosol behavior prediction models

An Investigation of Tic Suppression and the Rebound Effect in Tourette's Disorder

Science.gov (United States)

Meidinger, Amy L.; Miltenberger, Raymond G.; Himle, Michael; Omvig, Matthew; Trainor, Casey; Crosby, Ross

2005-01-01

Many patients, parents of children with Tourettes disorder, and professionals have suggested that following a period of suppression, tics will rebound to a rate that will exceed the average rate of occurrence. At present, there are no empirical data to support or refute such an effect. This experiment utilized an A-B-A design with replication to…

Intraocular pressure measurement over soft contact lens by rebound tonometer:a comparative study

Directory of Open Access Journals (Sweden)

Senay Asik Nacaroglu

2015-06-01

Full Text Available AIM: To evaluate the intraocular pressure (IOP measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry (GAT.METHODS: Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens (RTCL, RT respectively and by GAT, as well as their central corneal thickness (CCT by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman analysis.RESULTS: Mean IOP values measured by RTCL, RT and GAT were 15.68±3.7, 14.50±3.4 and 14.16±2.8 (P<0.001, respectively. Mean IOP by RTCL was significantly higher than the measurements implemented by RT and GAT (P<0.001, while there was no difference between the measurements by GAT and RT (P=0.629. There was a good level of positive correlation between GAT and RTCL as well as RT (r=0.786 P<0.001, r=0.833 P<0.001, respectively. We have observed that CCT increase did not show any correlation with the differences of the measurements between RTCL and RT (P=0.329, RTCL and GAT (P=0.07 as well as RT and GAT (P=0.189 in linear regression model.CONCLUSION: The average of the measurements over contact lens by rebound tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population.

Optical characteristics of particles produced using electroerosion dispersion of titanium in hydrogen peroxide

Science.gov (United States)

Pyachin, S. A.; Burkov, A. A.; Makarevich, K. S.; Zaitsev, A. V.; Karpovich, N. F.; Ermakov, M. A.

2016-07-01

Titanium oxide particles are produced using electric-discharge dispersion of titanium in aqueous solution of hydrogen peroxide. Electron vacuum microscopy, X-ray diffraction, and diffuse reflection spectroscopy are used to study the morphology, composition, and optical characteristics of the erosion particles. It has been demonstrated that the particles consist of titanium and titanium oxides with different valences. The edge of the optical absorption is located in the UV spectral range. The band gap is 3.35 eV for indirect transitions and 3.87 eV for direct allowed transitions. The band gap decreases due to the relatively long heating in air at a temperature of 480-550°C, so that powder oxide compositions can be obtained, the optical characteristics of which are similar to optical characteristics of anatase. The erosion products are completely oxidized to rutile after annealing in air at a temperature of 1000°C.

Prediction of indoor concentration of 0.5-4 µm particles of outdoor origin in an uninhabited apartment

DEFF Research Database (Denmark)

Schneider, T.; Jensen, K.A.; Clausen, P.A.

2004-01-01

Indoor and outdoor particle size distributions, indoor-outdoor pressure difference, indoor air-exchange rate, and meteorological conditions were measured at an uninhabited apartment located in a busy street in Copenhagen during 1-month long fall, winter and spring campaigns. Particle penetration...... was estimated from concentration rebound measurements following HEPA filtering of the indoor air by fitting a simple deterministic model. The model included measured air exchange rates and published surface deposition loss rates. This model was then used to predict indoor particle concentration. The model...

Plasma HIV Viral Rebound following Protocol-Indicated Cessation of ART Commenced in Primary and Chronic HIV Infection

DEFF Research Database (Denmark)

Hamlyn, Elizabeth; Ewings, Fiona M; Porter, Kholoud

2012-01-01

OBJECTIVES: The magnitude of HIV viral rebound following ART cessation has consequences for clinical outcome and onward transmission. We compared plasma viral load (pVL) rebound after stopping ART initiated in primary (PHI) and chronic HIV infection (CHI). DESIGN: Two populations with protocol......VL levels, at a median of 50 (95% CI 48-51) weeks after stopping ART. Four weeks after stopping treatment, although the proportion with pVL≥400 copies/ml was similar (78% PHI versus 79% CHI), levels were 0.45 (95% CI 0.26-0.64) log(10) copies/ml lower for PHI versus CHI, and remained lower up to 48 weeks...

[Clinical evaluation of the dynamic rebound tonometer Icare].

Science.gov (United States)

Detry-Morel, M; Jamart, J; Detry, M B; Pourjavan, S; Charlier, L; Dethinne, B; Huge, L; Ledoux, A

2006-12-01

The Icare dynamic tonometer (impact or Rebound tonometry) is a new tonometer based on making a moving object collide with an eye and on monitoring the motion parameters of this object following contact. The purpose of this study was to assess intra- and interobserver variability of IOP measurements with the Icare and their correlations with Goldmann applanation tonometry (GAT) and central corneal thickness (CCT). A prospective study including three groups of patients: group 1 (50 normal subjects), group 2 (50 patients with OHT or POAG and GAT IOP>22 mmHg), and group 3 (38 glaucomatous patients with GAT IOPtonometer can be used as a screening device for ocular hypertension as long as CCT measurements can be taken.

Stable Operation and Electricity Generating Characteristics of a Single-Cylinder Free Piston Engine Linear Generator: Simulation and Experiments

Directory of Open Access Journals (Sweden)

Huihua Feng

2015-01-01

Full Text Available We present a novel design of a single-cylinder free piston engine linear generator (FPELG incorporating a linear motor as a rebound device. A systematic simulation model of this FPELG system was built containing a kinematic and dynamic model of the piston and mover, a magneto-electric model of the linear generator, a thermodynamic model of the single-cylinder engine, and a friction model between the piston ring and cylinder liner. Simulations were performed to understand the relationships between pre-set motor parameters and the running performance of the FPELG. From the simulation results, it was found that a motor rebound force with a parabolic profile had clear advantages over a force with a triangular profile, such as a higher running frequency and peak cylinder pressure, faster piston motion, etc. The rebound position and the amplitude of rebound force were also determined by simulations. The energy conversion characteristics of the generator were obtained from our FPELG test rig. The parameters of intake pressure, motor frequency, and load resistance were varied over certain ranges, and relationships among these three parameters were obtained. The electricity-generating characteristic parameters include output power and system efficiency, which can measure the quality of matching the controllable parameters. The output power can reach 25.9 W and the system efficiency can reach 13.7%. The results in terms of matching parameters and electricity-generating characteristics should be useful to future research in adapting these engines to various operating modes.

Increased energy efficiency and the rebound effect: Effects on consumption and emissions

International Nuclear Information System (INIS)

Braennlund, Runar; Ghalwash, Tarek; Nordstroem, Jonas

2007-01-01

The main objective of this paper is to examine how exogenous technological progress, in terms of an increase in energy efficiency, affects consumption choice by Swedish households and thereby emissions of carbon dioxide (CO 2 ), sulphur dioxide (SO 2 ) and nitrogen oxide (NO x ). The aim of the paper is closely related to the discussion of what is termed the 'rebound effect'. To neutralise the rebound effect, we estimate the necessary change in CO 2 tax, i.e. the CO 2 tax that keeps CO 2 emissions at their initial level. In addition, we estimate how this will affect emissions of sulphur dioxide and nitrogen oxides. The results indicate that an increase in energy efficiency of 20% will increase emissions of CO 2 by approximately 5%. To reduce the CO 2 emissions to their initial level, the CO 2 tax must be raised by 130%. This tax increase will reduce the emissions of sulphur dioxide to below their initial level, but will leave the emissions of nitrogen oxides at a higher level than initially. Thus, if marginal damages from sulphur dioxide and nitrogen dioxide are non-constant, additional policy instruments are needed

Attachment styles and personal growth following romantic breakups: the mediating roles of distress, rumination, and tendency to rebound.

Directory of Open Access Journals (Sweden)

Tara C Marshall

Full Text Available The purpose of this research was to examine the associations of attachment anxiety and avoidance with personal growth following relationship dissolution, and to test breakup distress, rumination, and tendency to rebound with new partners as mediators of these associations. Study 1 (N = 411 and Study 2 (N = 465 measured attachment style, breakup distress, and personal growth; Study 2 additionally measured ruminative reflection, brooding, and proclivity to rebound with new partners. Structural equation modelling revealed in both studies that anxiety was indirectly associated with greater personal growth through heightened breakup distress, whereas avoidance was indirectly associated with lower personal growth through inhibited breakup distress. Study 2 further showed that the positive association of breakup distress with personal growth was accounted for by enhanced reflection and brooding, and that anxious individuals' greater personal growth was also explained by their proclivity to rebound. These findings suggest that anxious individuals' hyperactivated breakup distress may act as a catalyst for personal growth by promoting the cognitive processing of breakup-related thoughts and emotions, whereas avoidant individuals' deactivated distress may inhibit personal growth by suppressing this cognitive work.

Interactive Football-Training Based on Rebounders with Hit Position Sensing and Audio-Visual Feedback

DEFF Research Database (Denmark)

Jensen, Mads Møller; Grønbæk, Kaj; Thomassen, Nikolaj

2014-01-01

. However, most of these tools are created with a single goal, either to measure or train, and are often used and tested in very controlled settings. In this paper, we present an interactive football-training platform, called Football Lab, featuring sensor- mounted rebounders as well as audio-visual...

Effect of Particle Acceleration Process on the Flare Characteristics of ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

J. Astrophys. Astr. (2002) 23, 95–99. Effect of Particle Acceleration Process on the Flare Characteristics of. Blazars. S. Bhattacharyya, S. Sahayanathan & C. L. Kaul Nuclear Research Laboratory,. Bhabha Atomic Research Centre, Mumbai 400 085, India. Abstract. Following the kinetic equation approach, we study the flare.

Retroviral rebound syndrome after treatment discontinuation in a 15 year old girl with HIV attracted through mother-to-child transmission: case report

OpenAIRE

Gisslén Magnus; Friman Vanda

2007-01-01

Abstract A case of a 15 year old girl with retroviral rebound syndrome after discontinuation of highly active antiretroviral treatment (HAART) due to side effects is presented. The patient was transmitted with HIV at birth by her mother. She had recovered from severe AIDS after HAART was initiated five years earlier. This is the first case reported in the literature of retroviral rebound syndrome in a vertically transmitted HIV-infected patient.

Geochemically structural characteristics of municipal solid waste incineration fly ash particles and mineralogical surface conversions by chelate treatment.

Science.gov (United States)

Kitamura, Hiroki; Sawada, Takaya; Shimaoka, Takayuki; Takahashi, Fumitake

2016-01-01

Leaching behaviors of heavy metals contained in municipal solid waste incineration (MSWI) fly ash have been studied well. However, micro-characteristics of MSWI fly ash particles are still uncertain and might be non-negligible to describe their leaching behaviors. Therefore, this study investigated micro-characteristics of MSWI fly ash particles, especially their structural properties and impacts of chelate treatment on surface characteristics. According to SEM observations, raw fly ash particles could be categorized into four types based on their shapes. Because chelate treatment changed the surface of fly ash particles dramatically owing to secondary mineral formations like ettringite, two more types could be categorized for chelate-treated fly ash particles. Acid extraction experiments suggest that fly ash particles, tested in this study, consist of Si-base insoluble core structure, Al/Ca/Si-base semi-soluble matrices inside the body, and KCl/NaCl-base soluble aggregates on the surface. Scanning electron microscope (SEM) observations of the same fly ash particles during twice moistening treatments showed that KCl/NaCl moved under wet condition and concentrated at different places on the particle surface. However, element mobility depended on secondary mineral formations. When insoluble mineral like gypsum was generated and covered the particle surface, it inhibited element transfer under wet condition. Surface characteristics including secondary mineral formation of MSWI fly ash particles are likely non-negligible to describe trace element leaching behaviors.

Exploration of probability distribution of velocities of saltating sand particles based on the stochastic particle-bed collisions

International Nuclear Information System (INIS)

Zheng Xiaojing; Xie Li; Zhou Youhe

2005-01-01

The wind-blown sand saltating movement is mainly categorized into two mechanical processes, that is, the interaction between the moving sand particles and the wind in the saltation layer, and the collisions of incident particles with sand bed, and the latter produces a lift-off velocity of a sand particle moving into saltation. In this Letter a methodology of phenomenological analysis is presented to get probability density (distribution) function (pdf) of the lift-off velocity of sand particles from sand bed based on the stochastic particle-bed collision. After the sand particles are dealt with by uniform circular disks and a 2D collision between an incident particle and the granular bed is employed, we get the analytical formulas of lift-off velocity of ejected and rebound particles in saltation, which are functions of some random parameters such as angle and magnitude of incident velocity of the impacting particles, impact and contact angles between the collision particles, and creeping velocity of sand particles, etc. By introducing the probability density functions (pdf's) of these parameters in communion with all possible patterns of sand bed and all possible particle-bed collisions, and using the essential arithmetic of multi-dimension random variables' pdf, the pdf's of lift-off velocities are deduced out and expressed by the pdf's of the random parameters in the collisions. The numerical results of the distributions of lift-off velocities display that they agree well with experimental ones

2011 Mound Site Groundwater Plume Rebound Exercise and Follow-Up - 13440

Energy Technology Data Exchange (ETDEWEB)

Hooten, Gwendolyn [Mound Site Manager, U.S. Department of Energy Office of Legacy Management, Harrison, Ohio (United States); Cato, Rebecca; Lupton, Greg [S.M. Stoller Company, contractor to the U.S. Department of Energy Office of Legacy Management (United States)

2013-07-01

The Mound Site facility near Miamisburg, Ohio, opened in 1948 to support early atomic weapons programs. It grew into a research, development, and production facility performing work in support of the U.S. Department of Energy (DOE) weapons and energy programs. The plant was in operation until 1995. During the course of operation, an onsite landfill was created. The landfill was located over a finger of a buried valley aquifer, which is a sole drinking water source for much of the Miami Valley. In the 1980's, volatile organic compounds (VOCs) were discovered in groundwater at the Mound site. The site was placed on the National Priorities List on November 21, 1989. DOE signed a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Federal Facility Agreement with the U.S. Environmental Protection Agency (EPA) and the Ohio Environmental Protection Agency. The agreement became effective in October 1990. The area that included the landfill was designated Operational Unit 1 (OU-1). In 1995, a Record of Decision was signed that called for the installation and operation of a pump and treatment (P and T) system in order to prevent the VOCs in OU-1 groundwater from being captured by the onsite water production wells. In addition to the P and T system, a soil vapor extraction (SVE) system was installed in 1997 to accelerate removal of VOCs from groundwater in the OU-1 area. The SVE system was successful in removing large amounts of VOCs and continued to operate until 2007, when the amount of VOCs removed became minimal. A rebound study was started in February 2003 to determine how the groundwater system and contaminants would respond to shutting down the P and T system. The rebound test was stopped in February 2004 because predetermined VOC threshold concentrations were exceeded down-gradient of the landfill. The P and T and SVE systems were restarted after the termination of the rebound test. In 2006, the remediation of the Mound site was

The effect of hydrogel and silicone hydrogel contact lenses on the measurement of intraocular pressure with rebound tonometry.

Science.gov (United States)

Zeri, Fabrizio; Calcatelli, Paolo; Donini, Bernardo; Lupelli, Luigi; Zarrilli, Luciana; Swann, Peter G

2011-12-01

To assess the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over disposable hydrogel (etafilcon A) and silicone hydrogel (senofilcon A) contact lenses (CLs) of different powers. The experimental group comprised 36 subjects (19 male, 17 female). IOP measurements were undertaken on the subject's right eyes in random order using a rebound tonometer (ICare). The CLs had powers of +2.00D, -2.00D and -6.00D. Six measurements were taken over each contact lens and also before and after the CLs had been worn. A good correlation was found between IOP measurements with and without CLs (all r≥0.80; pContact Lens Association. Published by Elsevier Ltd. All rights reserved.

Surface tension effects on the behavior of a cavity growing, collapsing, and rebounding near a rigid wall.

Science.gov (United States)

Zhang, Zhen-yu; Zhang, Hui-sheng

2004-11-01

Surface tension effects on the behavior of a pure vapor cavity or a cavity containing some noncondensible contents, which is growing, collapsing, and rebounding axisymmetrically near a rigid wall, are investigated numerically by the boundary integral method for different values of dimensionless stand-off parameter gamma, buoyancy parameter delta, and surface tension parameter beta. It is found that at the late stage of the collapse, if the resultant action of the Bjerknes force and the buoyancy force is not small, surface tension will not have significant effects on bubble behavior except that the bubble collapse time is shortened and the liquid jet becomes wider. If the resultant action of the two force is small enough, surface tension will have significant and in some cases substantial effects on bubble behavior, such as changing the direction of the liquid jet, making a new liquid jet appear, in some cases preventing the bubble from rebound before jet impact, and in other cases causing the bubble to rebound or even recollapse before jet impact. The mechanism of surface tension effects on the collapsing behavior of a cavity has been analyzed. The mechanisms of some complicated phenomena induced by surface tension effects are illustrated by analysis of the computed velocity fields and pressure contours of the liquid flow outside the bubble at different stages of the bubble evolution.

Modeling of conductive particle motion in viscous medium affected by an electric field considering particle-electrode interactions and microdischarge phenomenon

Science.gov (United States)

Eslami, Ghiyam; Esmaeilzadeh, Esmaeil; Pérez, Alberto T.

2016-10-01

Up and down motion of a spherical conductive particle in dielectric viscous fluid driven by a DC electric field between two parallel electrodes was investigated. A nonlinear differential equation, governing the particle dynamics, was derived, based on Newton's second law of mechanics, and solved numerically. All the pertaining dimensionless groups were extracted. In contrast to similar previous works, hydrodynamic interaction between the particle and the electrodes, as well as image electric forces, has been taken into account. Furthermore, the influence of the microdischarge produced between the electrodes and the approaching particle on the particle dynamics has been included in the model. The model results were compared with experimental data available in the literature, as well as with some additional experimental data obtained through the present study showing very good agreement. The results indicate that the wall hydrodynamic effect and the dielectric liquid ionic conductivity are very dominant factors determining the particle trajectory. A lower bound is derived for the charge transferred to the particle while rebounding from an electrode. It is found that the time and length scales of the post-microdischarge motion of the particle can be as small as microsecond and micrometer, respectively. The model is able to predict the so called settling/dwelling time phenomenon for the first time.

Estimating broad-brush rebound effects for household energy consumption in the EU 28 countries and Norway: some policy implications of Odyssee data

International Nuclear Information System (INIS)

Galvin, Ray

2014-01-01

Currently there is a strong policy commitment in European Union (EU) and Organisation for Economic Co-operation and Development (OECD) countries to increase the energy efficiency of residential buildings, and it is widely assumed that this will naturally and automatically reduce domestic energy consumption. However, other factors such as fuel prices, wages, attitudes and lifestyles also influence energy consumption. This paper calculates broad-brush rebound effects based on changes in energy efficiency and energy consumption in each of the 28 EU countries plus Norway, for the years 2000–2011. In doing so, it tests how well the assumption of energy efficiency leading to energy reduction stands up to scrutiny in these lands. It uses the EU’s Odyssee database for efficiency and consumption figures and a commonly employed econometric definition of the rebound effect as an energy-efficiency elasticity. Most older EU lands show rebound effects in the expected range of 0–50%. However, the range for newer EU countries is 100–550%, suggesting that energy efficiency increases are not a good predictor of energy consumption. A more in-depth look at one country, Germany, suggests these results underestimate the rebound effect significantly. This also identifies research needs for specific energy consumption determinants in each country, to find more precisely what is driving consumption levels. - Highlights: • Policymakers frequently link energy efficiency gains with energy consumption falls. • Household energy rebound effects are calculated for EU lands using Odyssee data. • Most older EU lands show results in the range of 0–50% but newer lands show 100–552%. • Energy efficiency gains are not always a reliable predictor of energy consumption. • Targeted research could explore why consumption is often so unrelated to efficiency

Fractal and Morphological Characteristics of Single Marble Particle Crushing in Uniaxial Compression Tests

Directory of Open Access Journals (Sweden)

Yidong Wang

2015-01-01

Full Text Available Crushing of rock particles is a phenomenon commonly encountered in geotechnical engineering practice. It is however difficult to study the crushing of rock particles using classical theory because the physical structure of the particles is complex and irregular. This paper aims at evaluating fractal and morphological characteristics of single rock particle. A large number of particle crushing tests are conducted on single rock particle. The force-displacement curves and the particle size distributions (PSD of crushed particles are analysed based on particle crushing tests. Particle shape plays an important role in both the micro- and macroscale responses of a granular assembly. The PSD of an assortment of rocks are analysed by fractal methods, and the fractal dimension is obtained. A theoretical formula for particle crushing strength is derived, utilising the fractal model, and a simple method is proposed for predicting the probability of particle survival based on the Weibull statistics. Based on a few physical assumptions, simple equations are derived for determining particle crushing energy. The results of applying these equations are tested against the actual experimental data and prove to be very consistent. Fractal theory is therefore applicable for analysis of particle crushing.

Universal characteristics of particle shape evolution by bed-load chipping

Science.gov (United States)

Sipos, András Árpád; Shaw, Sam; Sarti, Giovanni; Domokos, Gábor

2018-01-01

River currents, wind, and waves drive bed-load transport, in which sediment particles collide with each other and Earth’s surface. A generic consequence is impact attrition and rounding of particles as a result of chipping, often referred to in geological literature as abrasion. Recent studies have shown that the rounding of river pebbles can be modeled as diffusion of surface curvature, indicating that geometric aspects of impact attrition are insensitive to details of collisions and material properties. We present data from fluvial, aeolian, and coastal environments and laboratory experiments that suggest a common relation between circularity and mass attrition for particles transported as bed load. Theory and simulations demonstrate that universal characteristics of shape evolution arise because of three constraints: (i) Initial particles are mildly elongated fragments, (ii) particles collide with similarly-sized particles or the bed, and (iii) collision energy is small enough that chipping dominates over fragmentation but large enough that sliding friction is negligible. We show that bed-load transport selects these constraints, providing the foundation to estimate a particle’s attrition rate from its shape alone in most sedimentary environments. These findings may be used to determine the contribution of attrition to downstream fining in rivers and deserts and to infer transport conditions using only images of sediment grains. PMID:29670937

Comparability of estimating energy rebound effect should be based on uniform mechanism and benchmark: A reply to Du and Lin

International Nuclear Information System (INIS)

Li, Chengyu; Shao, Shuai; Yang, Lili; Yu, Mingliang

2016-01-01

Du and Lin (2015) argued that the estimation model of the economy-wide energy rebound effect proposed by Shao et al. (2014) should be revised and provided an alternative approach, which they considered to be more consistent with the definition of the rebound effect. However, in this comment, we do not find a valid correction or modification to our original model, because their criticism logic does not originate from the corresponding mechanism in Shao et al. (2014), and their estimation formula has a different benchmark with ours. Moreover, their data samples were also different from ours, generating the incomparable results, and there are some irrational results in the comment. Even based on different estimation formulas in the two studies and using the same estimation method and data sample, the comparison results show that the problem of the estimation formula in our previous study which they claimed does not really exist. We argue that this comment is not consistent with the principle of the rebound effect. Actually, their work can be only regarded as proposing an alternative approach for the estimate of the rebound effect. Therefore, their argument is not enough to overturn our previous study. - Highlights: • A reply to Du and Lin (2015), who questioned our previous study, is provided. • Their criticism logic does not originate from our corresponding mechanism. • Their estimation formula has a different benchmark with ours. • Different data samples in the two papers make their results incomparable. • Their argument is not enough to overturn our previous study.

Physical Principles of the Method for Determination of Geometrical Characteristics and Particle Recognition in Digital Holography

Science.gov (United States)

Dyomin, V. V.; Polovtsev, I. G.; Davydova, A. Yu.

2018-03-01

The physical principles of a method for determination of geometrical characteristics of particles and particle recognition based on the concepts of digital holography, followed by processing of the particle images reconstructed from the digital hologram, using the morphological parameter are reported. An example of application of this method for fast plankton particle recognition is given.

Heterogeneity in the response to gasoline prices: Evidence from Pennsylvania and implications for the rebound effect

International Nuclear Information System (INIS)

Gillingham, Kenneth; Jenn, Alan; Azevedo, Inês M.L.

2015-01-01

The consumer response to changing gasoline prices has long interested economists and policymakers, for it has important implications for the effects of gasoline taxation and vehicle energy efficiency policies. This study examines both the elasticity of driving with respect to changing gasoline prices and heterogeneity in this elasticity by geography, the fuel economy of the vehicle, and the age of the vehicle. We use detailed annual vehicle-level emissions inspection test data from Pennsylvania that include odometer readings, inspection zip codes, and extensive vehicle characteristics. We estimate a short-run gasoline price elasticity of driving demand of − 0.10, and find substantial heterogeneity in this responsiveness. The elasticity is largely driven by low fuel economy vehicles, as well as vehicles between 3 and 7 years old. Our findings help reconcile some of the recent literature and provide guidance on the magnitude of the direct rebound effect from light duty vehicle energy efficiency policies.

Measurement and modeling the coefficient of restitution of char particles under simulated entrained flow gasifier conditions

Science.gov (United States)

Gibson, LaTosha M.

Inefficiencies in plant operations due to carbon loss in flyash, necessitate control of ash deposition and the handling of the slag disposal. Excessive char/ash deposition in convective coolers causes reduction in the heat transfer, both in the radiative (slagging) section and in the low-temperature convective (fouling) heating section. This can lead to unplanned shutdowns and result in an increased cost of electricity generation. CFD models for entrained flow gasification have used the average bulk coal composition to simulate slagging and ash deposition with a narrow particle size distribution (PSD). However, the variations in mineral (inorganic) and macerals (organic) components in coal have led to particles with a variation in their inorganic and organic composition after grinding as governed by their Particle Size Distribution (PSD) and mineral liberation kinetics. As a result, each particle in a PSD of coal exhibits differences in its conversion, particle trajectory within the gasifier, fragmentation, swelling, and slagging probability depending on the gasifier conditions (such as the temperature, coal to oxygen ratio, and swirling capacity of the coal injector). Given the heterogeneous behavior of char particles within a gasifier, the main objective of this work was to determine boundary conditions of char particle adhering and/or rebounding from the refractory wall or a layer of previously adhered particles. In the past, viscosity models based on the influence of ash composition have been used as the method to characterize sticking. It is well documented that carbon contributes to the non-wettability of particles. Therefore, it has been hypothesized that viscosity models would not be adequate to accurately predict the adhesion behavior of char. Certain particle wall impact models have incorporated surface tension which can account the contributions of the carbon content to the adhesive properties of a char particle. These particle wall impact models also

Annealing effects on the charged particles registration characteristic of the CR-39 traces solid detector

International Nuclear Information System (INIS)

Correa, M.M.

1989-10-01

CR-39 trace solid detectors samples, previously exposed to alpha particles and fission fragments from a Cf-252 source, were submitted to a annealing treatment to study his effects on the characteristics of charged particle traces registration. (L.C.J.A.)

Characteristics of airflow and particle deposition in COPD current smokers

Science.gov (United States)

Zou, Chunrui; Choi, Jiwoong; Haghighi, Babak; Choi, Sanghun; Hoffman, Eric A.; Lin, Ching-Long

2017-11-01

A recent imaging-based cluster analysis of computed tomography (CT) lung images in a chronic obstructive pulmonary disease (COPD) cohort identified four clusters, viz. disease sub-populations. Cluster 1 had relatively normal airway structures; Cluster 2 had wall thickening; Cluster 3 exhibited decreased wall thickness and luminal narrowing; Cluster 4 had a significant decrease of luminal diameter and a significant reduction of lung deformation, thus having relatively low pulmonary functions. To better understand the characteristics of airflow and particle deposition in these clusters, we performed computational fluid and particle dynamics analyses on representative cluster patients and healthy controls using CT-based airway models and subject-specific 3D-1D coupled boundary conditions. The results show that particle deposition in central airways of cluster 4 patients was noticeably increased especially with increasing particle size despite reduced vital capacity as compared to other clusters and healthy controls. This may be attributable in part to significant airway constriction in cluster 4. This study demonstrates the potential application of cluster-guided CFD analysis in disease populations. NIH Grants U01HL114494 and S10-RR022421, and FDA Grant U01FD005837.

Economic and environmental gains of China's fossil energy subsidies reform: A rebound effect case study with EIMO model

International Nuclear Information System (INIS)

Hong, Li; Liang, Dong; Di, Wang

2013-01-01

Energy consumption and efficiency emerged as the hottest topic in the context of China's sustainable development. Energy subsidies and “rebound effect” were closely related to this topic while few combinative studies on them with a focus on China. This paper employed a co-thinking approach, focusing on how the energy subsidies reform could mitigate the rebound effect in China, and how to achieve an “economic and environmental gains” that reduced pecuniary spending, improved the distorted energy market and reduced energy consumption simultaneously. Firstly, with price-gap approach we calculated the total energy subsidies scale of China in 2007, which amounted to582.0 billion CNY; then we detected and identified rebound effect of China energy consumption with the features. Furthermore, based on China 2007 monetary input–output table and energy flow analysis, we compiled a hybrid physical energy input and monetary output model (EIMO) to simulate the mitigation effect of subsidies reform. Results showed that removing energy subsidies would decrease ultimate demand of different economy sectors and reduce the accumulatively physical consumption of coal, oil, natural gas and electricity by 17.74, 13.47, 3.64 and 15.82 million tce, respectively. Finally we discussed relevant policy issues on China's energy subsidies reform in depth. - Highlights: ► Analyze the economic and environmental gains of fossil energy subsidies reform in China. ► Energy input and monetary output model was applied for analysis. ► Subsidies reform would help to reduce the rebound effect. ► The benefits of money saving, energy saving and CO 2 mitigation were achieved

Particle characteristics and reduction behavior of synthetic magnetite

International Nuclear Information System (INIS)

Ramadan, Wegdan; Zaki, Mohamed I.; Fouad, Nasr E.; Mekhemer, Gamal A.H.

2014-01-01

Two samples (S1 and S2) of magnetite were synthesized, using two different methods, and characterized by means of X-ray powder diffractometry, infrared and Mössbauer spectroscopy, N 2 sorptiometry and electron microscopy. Particles of sample-S1 were found to be loosely agglomerated, micro-sized spheroids (200–350 nm) composed almost solely of highly aggregated (fused) crystallites (size averaged at 35 nm) of cubic-Fe 3 O 4 . In contrast, particles of sample-S2 were strongly agglomerated, nano-sized spheroids (25–30 nm) composed of slightly aggregated crystallites (size averaged at 11 nm) of cubic-Fe 3 O 4 and noncrystalline domains made-up of FeO(OH) species. Temperature-programed reduction (TPR) profiles obtained for the two samples were similar in monitoring two peaks at >450 °C assignable to a two-step reduction of Fe 3 O 4 (→FeO→Fe), but different in monitoring a peak at 3 O 4 ) contained in sample-S2. However, curve fitting analysis of the TPR profiles and molecular stoichiometry calculations based on amounts of hydrogen consumed revealed that the two-step reduction of Fe 3 O 4 is not straightforward. That is by resolving two consecutive pathways for each step and, hence, nonstoichiometric intermediate products whose composition was found to be critically controlled by the composition of the reducing gas atmosphere (5 or 80% H 2 /N 2 ) and characteristics of the starting sample particles (chemical and phase composition, and, but to lesser extents, the agglomeration and average size). - Highlights: • Nano or micro, pure Fe 3 O 4 particles are H 2 -reduced in two steps (→FeO→Fe) at >450 °C. • FeO(OH)-impure particles exhibit a third reduction step (FeO(OH)→Fe 3 O 4 ) at 3 O 4 reduction steps resolves two consecutive pathways. • Moreover, various nonstoichiometric reduction intermediate products are genesized

Deposition characteristics of copper particles on roughened substrates through kinetic spraying

International Nuclear Information System (INIS)

Kumar, S.; Bae, Gyuyeol; Lee, Changhee

2009-01-01

In this paper, a systematic study of copper particle deposition behavior on polished and roughened surfaces (aluminum and copper) in kinetic spray process has been performed. The particle deformation behavior was simulated through finite element analysis (FEA) software ABAQUS explicit 6.7-2. The particle-substrate contact time, contact temperature and contact area upon impact have been estimated for smooth and three different roughened substrate cases. Copper powders were deposited on smooth and grit-blasted copper and aluminium substrates and characterized through scanning electron microscopy and Romulus bond strength analyzer. The results indicate that the deformation and the resultant bonding were higher for the roughened substrates than that of smooth. The characteristic factors for bonding are reported and discussed. Thus the substrate roughness appears to be beneficial for the initial deposition efficiency of the kinetic spray process.

Characteristics of eugenol loaded chitosan-tripolyphosphate particles as affected by initial content of eugenol and their in-vitro release characteristic

Science.gov (United States)

Cahyono, B.; A’yun, Qurrotu; Suzery, M.; Hadiyanto

2018-04-01

The aim of this research was to determine encapsulation efficiency, loading capacity and controlled release of eugenol loaded chitosan-tpp products which prepared by coaservation method. The characteristic of eugenol-loaded chitosan showed that %EE and % LC increased by increasing the initial eugenol content. The optimum of %EE (72.63%) and %LC (43.96%) were obtained at the ratio of chitosan to eugenol of 1:1.5. The FTIR spectrum showed the characteristic peaks of eugenol appearing on spectrum of eugenol encapsulated and blue-shift in the hydroxyl band from 3425.58 cm-1 in chitosan-tpp to 3417.86 cm-1 and 3394.72 cm-1 in eugenol loaded chitosan-tpp indicating that eugenol was successfully encapsulated. The surface morphologies of freeze-dried particles with the optimum %EE showed that more surface roughness and porosity than plain particles. Furthermore, the in vitro release of particles with minimum and optimum %EE were also investigated in acid (Simulated Gastric Fluid) and base (Simulated Intestinal Fluid) medium at ambient temperature.

Force and Motion Characteristics of Contamination Particles near the High Voltage End of UHVDC Insulator

Directory of Open Access Journals (Sweden)

Lei Lan

2017-07-01

Full Text Available It is important to reveal the relations of physical factors to deposition of contaminants on insulator. In this paper, the simulation model of high voltage end of insulator was established to study the force and motion characteristics of particles affected by electric force and airflow drag force near the ultra-high voltage direct current (UHVDC insulator. By finite element method, the electric field was set specially to be similar to the one near practical insulator, the steady fluid field was simulated. The electric force and air drag force were loaded on the uniformly charged particles. The characteristics of the two forces on particles, the relationship between quantity of electric charge on particles and probability of particles contacting the insulator were analyzed. It was found that, near the sheds, airflow drag force on particles is significantly greater than electric force with less electric charge. As the charge multiplies, electric force increases linearly, airflow drag force grows more slowly. There is a trend that the magnitude of electric force and drag force is going to similar. Meanwhile, the probability of particles contacting the insulator is increased too. However, at a certain level of charge which has different value with different airflow velocity, the contact probability has extremum here. After exceeding the value, as the charge increasing, the contact probability decreases gradually.

Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

DEFF Research Database (Denmark)

Lieke, Kirsten Inga; Rosenørn, Thomas; Pedersen, Jannik

2013-01-01

microscopy (TEM) grids on two stages. Micro- and nanostructural characteristics of sin-gle particles were studied by TEM. Image analysis was carried out on overview and high-resolution images, revealing influence of the exhaust gas treatment (scrubber) on the particle morphology and mixing state. Soot......This work provides insight into the morphology and mixing state of submicron particles in diesel exhaust from a ship engine with an exhaust gas recirculation scrubber. Particles from this low-speed ship engine on test bed were collected using a microiner-tial impactor with transmission electron...

Effects of species-specific leaf characteristics and reduced water availability on fine particle capture efficiency of trees

International Nuclear Information System (INIS)

Räsänen, Janne V.; Holopainen, Toini; Joutsensaari, Jorma; Ndam, Collins; Pasanen, Pertti; Rinnan, Åsmund; Kivimäenpää, Minna

2013-01-01

Trees can improve air quality by capturing particles in their foliage. We determined the particle capture efficiencies of coniferous Pinus sylvestris and three broadleaved species: Betula pendula, Betula pubescens and Tilia vulgaris in a wind tunnel using NaCl particles. The importance of leaf surface structure, physiology and moderate soil drought on the particle capture efficiencies of the trees were determined. The results confirm earlier findings of more efficient particle capture by conifers compared to broadleaved plants. The particle capture efficiency of P. sylvestris (0.21%) was significantly higher than those of B. pubescens, T. vulgaris and B. pendula (0.083%, 0.047%, 0.043%, respectively). The small leaf size of P. sylvestris was the major characteristic that increased particle capture. Among the broadleaved species, low leaf wettability, low stomatal density and leaf hairiness increased particle capture. Moderate soil drought tended to increase particle capture efficiency of P. sylvestris. -- Highlights: • Coniferous Scots pine was the most efficient particle collector. • Decreasing single leaf size increases particle deposition of the total leaf area. • Hairiness of the leaf increases particle deposition. -- Trees can improve air quality by removing PM 2.5 pollutants carried on the wind at a velocity of 3 m s −1 , the efficiency of which depends on species leaf characteristics and physical factors

Can Satellite Geodesy Disentangle Holocene Rebound and Present-Day Glacier Balance Signatures?

Science.gov (United States)

Irvins, E.; James, T.; Yoder, C.

1995-01-01

The secular drift of the precession of the ascending node of the LAGOES -1 satellite is apparently linked to the Earth s paleoclimate through the slow viscous response of the mantle to ice sheet/ocean mass transfer during the last great continental deglaciation . The secular node acceleration is particularly sensitive to the longest wavelengths of the paleo -surface loading that have been memorized by the mantle glacio -isostatic flow. Tide gauge records for the last 130 years show a post-glacial rebound-corrected sea-level rise of 2.4 n 0.9 mm yr-1.

A Simple extension of Dematerialization Theory: Incorporation of Technical Progress and the Rebound Effect

OpenAIRE

Magee, Christopher L.; Devezas, Tessaleno C.

2016-01-01

Dematerialization is the reduction in the quantity of materials needed to produce something useful over time. Dematerialization fundamentally derives from ongoing increases in technical performance but it can be counteracted by demand rebound - increases in usage because of increased value (or decreased cost) that also results from increasing technical performance. A major question then is to what extent technological performance improvement can offset and is offsetting continuously increasin...

Genetically-barcoded SIV facilitates enumeration of rebound variants and estimation of reactivation rates in nonhuman primates following interruption of suppressive antiretroviral therapy.

Directory of Open Access Journals (Sweden)

Christine M Fennessey

2017-05-01

Full Text Available HIV and SIV infection dynamics are commonly investigated by measuring plasma viral loads. However, this total viral load value represents the sum of many individual infection events, which are difficult to independently track using conventional sequencing approaches. To overcome this challenge, we generated a genetically tagged virus stock (SIVmac239M with a 34-base genetic barcode inserted between the vpx and vpr accessory genes of the infectious molecular clone SIVmac239. Next-generation sequencing of the virus stock identified at least 9,336 individual barcodes, or clonotypes, with an average genetic distance of 7 bases between any two barcodes. In vitro infection of rhesus CD4+ T cells and in vivo infection of rhesus macaques revealed levels of viral replication of SIVmac239M comparable to parental SIVmac239. After intravenous inoculation of 2.2x105 infectious units of SIVmac239M, an average of 1,247 barcodes were identified during acute infection in 26 infected rhesus macaques. Of the barcodes identified in the stock, at least 85.6% actively replicated in at least one animal, and on average each barcode was found in 5 monkeys. Four infected animals were treated with combination antiretroviral therapy (cART for 82 days starting on day 6 post-infection (study 1. Plasma viremia was reduced from >106 to <15 vRNA copies/mL by the time treatment was interrupted. Virus rapidly rebounded following treatment interruption and between 87 and 136 distinct clonotypes were detected in plasma at peak rebound viremia. This study confirmed that SIVmac239M viremia could be successfully curtailed with cART, and that upon cART discontinuation, rebounding viral variants could be identified and quantified. An additional 6 animals infected with SIVmac239M were treated with cART beginning on day 4 post-infection for 305, 374, or 482 days (study 2. Upon treatment interruption, between 4 and 8 distinct viral clonotypes were detected in each animal at peak rebound

Effect of carbonyl iron particles composition on the physical characteristics of MR grease

Energy Technology Data Exchange (ETDEWEB)

Mohamad, Norzilawati, E-mail: mnorzilawati@gmail.com; Mazlan, Saiful Amri, E-mail: amri.kl@utm.my [Vehicle System Engineering, Malaysia – Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra (Jalan Semarak), Kuala Lumpur, 54000 (Malaysia); Ubaidillah, E-mail: ubaidillah@uns.ac.id [Vehicle System Engineering, Malaysia – Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra (Jalan Semarak), Kuala Lumpur, 54000 (Malaysia); Mechanical Engineering Department, Faculty of Engineering, Universitas Sebelas Maret, Jl. Ir. Sutami 36A, Kentingan, Surakarta, 57126, Central Java, Surakarta (Indonesia)

2016-03-29

Magnetorheological (MR) grease is an extension of the study of magnetorheological materials. The MR grease can help to reduce the particles sedimentation problem occurred in the MR fluids. Within this study, an effort has been taken to investigate the effect of different weight compositions of carbonyl iron particles on the physical and chemical characteristics of the MR grease under off-state condition (no magnetic field). The MR grease is prepared by mixing carbonyl iron particles having a size range of 1 to 10 µm with commercial NPC Highrex HD-3 grease. Characterizations of MR grease are investigated using Vibrating Sample Magnetometer (VSM), Environmental Scanning Electron Microscopy (ESEM), Differential Scanning Calorimeter (DSC) and rheometer. The dependency of carbonyl iron particles weight towards the magnetic properties of MR grease and other characterizations are investigated.

Assessment of intraocular pressure in chinchillas of different age groups using rebound tonometry

Directory of Open Access Journals (Sweden)

Flor Diana Yokoay Claros Chacaltana

2016-01-01

Full Text Available ABSTRACT: The aim of this research was to measure the intraocular pressure (IOP of normal chinchilla eyes using the rebound tonometer. A further aim was to assess whether there were differences in the values of intraocular pressure in relation to animals age, gender and time of day. Thirty-six chinchillas were divided into three groups of 12 chinchillas each, by age: Group I (2-6-month-old, Group II (20 and 34 months and Group III (37 and 135 months. Ophthalmic examination was performed previously by Schirmer tear test, slit lamp biomicroscopy, indirect ophthalmoscopy and fluorescein test in all chinchillas. Three measurements of intraocular pressure were assessed on the same day (7, 12 and 19h. Tonometry was performed on both eyes using the rebound tonometer after calibration in "p" mode. Statistical analysis was performed with SigmaPlot for Windows. The mean IOP for groups I, II and III were 2.47±0.581mmHg, 2.47±0.581mmHg and 2.51±0.531mmHg, respectively. No significant differences were reported between age and IOP and no significant differences were reported between the time of day and IOP. The IOP in chinchillas did not differ significantly between genders or ages of the animals, and did not change with time of day.

Particle swarm optimization using multi-information characteristics of all personal-best information.

Science.gov (United States)

Huang, Song; Tian, Na; Wang, Yan; Ji, Zhicheng

2016-01-01

Convergence stagnation is the chief difficulty to solve hard optimization problems for most particle swarm optimization variants. To address this issue, a novel particle swarm optimization using multi-information characteristics of all personal-best information is developed in our research. In the modified algorithm, two positions are defined by personal-best positions and an improved cognition term with three positions of all personal-best information is used in velocity update equation to enhance the search capability. This strategy could make particles fly to a better direction by discovering useful information from all the personal-best positions. The validity of the proposed algorithm is assessed on twenty benchmark problems including unimodal, multimodal, rotated and shifted functions, and the results are compared with that obtained by some published variants of particle swarm optimization in the literature. Computational results demonstrate that the proposed algorithm finds several global optimum and high-quality solutions in most case with a fast convergence speed.

Surfactant effect on functionalized carbon nanotube coated snowman-like particles and their electro-responsive characteristics

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ke; Liu, Ying Dan [Department of Polymer Science and Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Choi, Hyoung Jin, E-mail: hjchoi@inha.ac.kr [Department of Polymer Science and Engineering, Inha University, Incheon 402-751 (Korea, Republic of)

2012-10-15

The core–shell structured snowman-like (SL) microparticles coated by functionalized multi-walled carbon nanotube (MWNT) were prepared in the presence of different surfactants including cationic surfactant-cetyl trimethylammonium bromide (CTAB) and anionic surfactant-sodium lauryl sulfate (SDS). The effect of surfactants on adsorption onto SL particles was characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and conductivity. The cationic surfactant is found to be more effective than anionic surfactant for helping nanotube adsorbed onto microparticle due to the presence of electrostatic interaction between the functionalized MWNT and the surfactant. Furthermore, the MWNT/SL particles dispersed in silicone oil exhibited a typical fibril structure of the electrorheological characteristics under an applied electric field observed by an optical microscope (OM), in which the state of nanotubes wrapped on the particles strongly affects their electro-responsive characteristics.

Surfactant effect on functionalized carbon nanotube coated snowman-like particles and their electro-responsive characteristics

International Nuclear Information System (INIS)

Zhang, Ke; Liu, Ying Dan; Choi, Hyoung Jin

2012-01-01

The core–shell structured snowman-like (SL) microparticles coated by functionalized multi-walled carbon nanotube (MWNT) were prepared in the presence of different surfactants including cationic surfactant-cetyl trimethylammonium bromide (CTAB) and anionic surfactant-sodium lauryl sulfate (SDS). The effect of surfactants on adsorption onto SL particles was characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and conductivity. The cationic surfactant is found to be more effective than anionic surfactant for helping nanotube adsorbed onto microparticle due to the presence of electrostatic interaction between the functionalized MWNT and the surfactant. Furthermore, the MWNT/SL particles dispersed in silicone oil exhibited a typical fibril structure of the electrorheological characteristics under an applied electric field observed by an optical microscope (OM), in which the state of nanotubes wrapped on the particles strongly affects their electro-responsive characteristics.

Visual Observation of Bubble Departure Characteristics in the Nano-particle Coated Heating Surface

International Nuclear Information System (INIS)

Han, Won Soek; Yoo, Shin; Lee, Jae Young

2010-01-01

Although the great enhancement of the thermal conductivity of the nanofluids, the fluid mixed with small amount of the nano meter sized particles, has been known, many experimental data of the boiling heat transfer reported degraded heat transfer rate than the fresh fluid. However, the great enhancement of the critical heat flux in nanofluids has been reported by many investigators. Due to the opaque scattering of the nano particles in nano fluids, direct observation of the bubble dynamics in the boiling process has not been made. However, it has been known that the boiling heat transfer characteristics of the heater coated by the nano particles in the fresh water are almost similar to that in the nano fluid. Recently, consensus has been made in the understanding of the CHF enhancement of nanofluids or nano-particle coated heater as the surface phenomena. Therefore, in the present paper, we do experimental study to observe the bubble departure in the pool boiling process with the nano-particle coated heater

Particle characteristics and reduction behavior of synthetic magnetite

Energy Technology Data Exchange (ETDEWEB)

Ramadan, Wegdan [Physics Department, Faculty of Science, Alexandria University, Alexandria 21511 (Egypt); Zaki, Mohamed I., E-mail: mizaki@link.net [Chemistry Department, Faculty of Science, Minia University, El-Minia 61519 (Egypt); Fouad, Nasr E.; Mekhemer, Gamal A.H. [Chemistry Department, Faculty of Science, Minia University, El-Minia 61519 (Egypt)

2014-04-15

Two samples (S1 and S2) of magnetite were synthesized, using two different methods, and characterized by means of X-ray powder diffractometry, infrared and Mössbauer spectroscopy, N{sub 2} sorptiometry and electron microscopy. Particles of sample-S1 were found to be loosely agglomerated, micro-sized spheroids (200–350 nm) composed almost solely of highly aggregated (fused) crystallites (size averaged at 35 nm) of cubic-Fe{sub 3}O{sub 4}. In contrast, particles of sample-S2 were strongly agglomerated, nano-sized spheroids (25–30 nm) composed of slightly aggregated crystallites (size averaged at 11 nm) of cubic-Fe{sub 3}O{sub 4} and noncrystalline domains made-up of FeO(OH) species. Temperature-programed reduction (TPR) profiles obtained for the two samples were similar in monitoring two peaks at >450 °C assignable to a two-step reduction of Fe{sub 3}O{sub 4} (→FeO→Fe), but different in monitoring a peak at<450 °C only for the reduction of FeO(OH) (→Fe{sub 3}O{sub 4}) contained in sample-S2. However, curve fitting analysis of the TPR profiles and molecular stoichiometry calculations based on amounts of hydrogen consumed revealed that the two-step reduction of Fe{sub 3}O{sub 4} is not straightforward. That is by resolving two consecutive pathways for each step and, hence, nonstoichiometric intermediate products whose composition was found to be critically controlled by the composition of the reducing gas atmosphere (5 or 80% H{sub 2}/N{sub 2}) and characteristics of the starting sample particles (chemical and phase composition, and, but to lesser extents, the agglomeration and average size). - Highlights: • Nano or micro, pure Fe{sub 3}O{sub 4} particles are H{sub 2}-reduced in two steps (→FeO→Fe) at >450 °C. • FeO(OH)-impure particles exhibit a third reduction step (FeO(OH)→Fe{sub 3}O{sub 4}) at <450 °C. • FeO disproportion and related autocatalytic effects complicate the reduction course. • Consequently, each of the Fe{sub 3}O{sub 4

Experimental Analysis of Damping and Tribological Characteristics of Nano-CuO Particle Mixed Lubricant in Ball Bearings

Science.gov (United States)

Prakash, E.; Sivakumar, K.

2015-12-01

Experimental analysis of damping capacity and tribological characteristics of nano CuO added Servosystem 68 lubricant is attempted. CuO nano particles were synthesized by aqueous precipitation method and characterized. Prior to dispersion into lubricant, CuO nano particles were coated with 0.2 wt.% surfactant (Span-80) to stabilize the nano fluid. Tribological characteristics of particle added lubricant were tested in ASTM D 4172 four ball wear tester. Scanning electron microscopy test results of worn surfaces of nano CuO particle added lubricant were smoother than base lubricant. The particle added lubricant was applied in a new ball bearing and three defected ball bearings. When particle added lubricant was used, the ball defected bearing's vibration amplitude was reduced by 21.94% whereas it was 16.46% for new bearing and was ≤ 11% for other defected bearings. The formation of protection film of CuO over ball surface and regime of full film lubrication near the ball zone were observed to be reason for improved damping of vibrations.

[Particle emission characteristics of diesel bus fueled with bio-diesel].

Science.gov (United States)

Lou, Di-Ming; Chen, Feng; Hu, Zhi-Yuan; Tan, Pi-Qiang; Hu, Wei

2013-10-01

With the use of the Engine Exhaust Particle Sizer (EEPS), a study on the characteristics of particle emissions was carried out on a China-IV diesel bus fueled with blends of 5% , 10% , 20% , 50% bio-diesel transformed from restaurant waste oil and China-IV diesel (marked separately by BD5, BD10, BD20, BD50), pure bio-diesel (BD100) and pure diesel (BD0). The results indicated that particulate number (PN) and mass (PM) emissions of bio-diesel blends increased with the increase in bus speed and acceleration; with increasing bio-diesel content, particulate emissions displayed a relevant declining trend. In different speed ranges, the size distribution of particulate number emissions (PNSD) was bimodal; in different acceleration ranges, PNSD showed a gradual transition from bimodal shape to unimodal when bus operation was switched from decelerating to accelerating status. Bio-diesel blends with higher mixture ratios showed significant reduction in PN emissions for accumulated modes, and the particulate number emission peaks moved towards smaller sizes; but little change was obtained in PN emissions for nuclei modes; reduction also occurred in particle geometric diameter (Dg).

Adsorption-Desorption Characteristics of Plutonium and Americium with Sediment Particles in the Estuarine Environment

International Nuclear Information System (INIS)

Murray, C.N.; Fukai, R.

1976-01-01

The particle formation of plutonium and americium, their adsorption onto fresh water sediments and the desorption from the sediments in sea water were studied in the Laboratory under simulated river-estuary conditions, using γ-emitting plutonium-237 and americium-241. The results of the experiments show that the particle formation of plutonium depends on its valence states, on pH and on the salinity of the medium. For river water at pH4, some 25%, 20% and 30% of the added 237 Pu was in particulate form, larger than 0.45pm, for Pu (III), Pu (IV) and Pu (VI), respectively, while 65%, 90% and 50% of the respective valence states was associated with particles at pH 8. In sea water the general pattern remains similar, although Pu (VI) is more soluble in sea water owing to higher ligand concentrations for carbonate and bicarbonate complexes. The pH-dependency of particle formation of Am (III) is more steep than that of plutonium and seems to be influenced by colloidal substances occurring in the experimental media. The adsorption-desorption characteristics of plutonium and americium with the sediment in river water as well as sea water reflect the characteristics of their particle formation, being dependent upon such properties as valence states, the pH and salinity of the medium. A sewage effluent added to the media has small but measurable effects on the adsorption-desorption processes of plutonium. (author)

Experimental study of the form of "hot" steel particles on the ignition characteristics of liquid fuels

Science.gov (United States)

Zakharevich, Arkadiy V.

2015-01-01

The results of an experimental study of laws governing the ignition of liquid propellants (kerosene, diesel fuel and petroleum residue) by the single spherical steel particle heated to high temperatures are presented. Is carried out the comparison of the ignition delay times of the investigated flammable substances by the particles in the sphere and disk forms. It is established that the particle shape does not exert a substantial influence on the ignition process characteristics.

DNA adsorption characteristics of hollow spherule allophane nano-particles

International Nuclear Information System (INIS)

Matsuura, Yoko; Iyoda, Fumitoshi; Arakawa, Shuichi; John, Baiju; Okamoto, Masami; Hayashi, Hidetomo

2013-01-01

To understand the propensity of natural allophane to adsorb the DNA molecules, the adsorption characteristics were assessed against natural allophane (AK70), using single-stranded DNA (ss-DNA) and adenosine 5′-monophosphate (5′-AMP) as a reference molecule. The adsorption capacity of ss-DNA on AK70 exhibited one order of magnitude lower value as compared with that of 5′-AMP. The adsorption capacity of ss-DNA decreased with increasing pH due to the interaction generated between phosphate groups of ss-DNA and functional Al–OH groups on the wall perforations through deprotonating, associated with higher energy barrier for the adsorption of ss-DNA. The adsorption morphologies consisting of the individual ss-DNA with mono-layer coverage of the clustered allophane particle were observed successfully through transmission electron microscopy analysis. - Highlights: • The interaction between phosphate groups of ss-DNA and Al–OH groups • Higher energy barrier for the adsorption of ss-DNA • The individual ss-DNA with mono-layer coverage of the allophane clustered particle

A method for separating Antarctic postglacial rebound and ice mass balance using future ICESat Geoscience Laser Altimeter System, Gravity Recovery and Climate Experiment, and GPS satellite data

OpenAIRE

Velicogna, Isabella; Wahr, John

2002-01-01

Measurements of ice elevation from the Geoscience Laser Altimeter System (GLAS) aboard the Ice, Cloud, and Land Elevation Satellite can be combined with time-variable geoid measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite mission to learn about ongoing changes in polar ice mass and viscoelastic rebound of the lithosphere under the ice sheet. We estimate the accuracy in recovering the spatially varying ice mass trend and postglacial rebound signals for Antarctica...

Ultrafine particle emission characteristics of diesel engine by on-board and test bench measurement.

Science.gov (United States)

Huang, Cheng; Lou, Diming; Hu, Zhiyuan; Tan, Piqiang; Yao, Di; Hu, Wei; Li, Peng; Ren, Jin; Chen, Changhong

2012-01-01

This study investigated the emission characteristics of ultrafine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engine to be in the range of (0.56-8.35) x 10(8) cm(-3). The on-board measurement results illustrated that the ultrafine particles were strongly correlated with changes in real-world driving cycles. The particle number concentration was down to 2.0 x 10(6) cm(-3) and 2.7 x 10(7) cm(-3) under decelerating and idling operations and as high as 5.0 x 10(8) cm(-3) under accelerating operation. It was also indicated that the particle number measured by the two methods increased with the growth of engine load at each engine speed in both cases. The particle number presented a "U" shaped distribution with changing speed at high engine load conditions, which implies that the particle number will reach its lowest level at medium engine speeds. The particle sizes of both measurements showed single mode distributions. The peak of particle size was located at about 50-80 nm in the accumulation mode particle range. Nucleation mode particles will significantly increase at low engine load operations like idling and decelerating caused by the high concentration of unburned organic compounds.

Hygroscopic influence on the semisolid-to-liquid transition of secondary organic materials.

Science.gov (United States)

Bateman, Adam P; Bertram, Allan K; Martin, Scot T

2015-05-14

The effect of relative humidity (RH) on the rebound of particles composed of isoprene, α-pinene, and toluene secondary organic materials (SOMs) was studied. A three-arm impaction apparatus was used to study rebound from 5 to 95% RH at 298 K. Calibration experiments using sucrose particles of variable but known viscosities showed that the transition from rebounding to adhering particles occurred for a change in viscosity from 100 to 1 Pa s, corresponding to a transition from semisolid to liquid material. The experimentally determined rebound fractions of the studied SOMs were compared with results from a model of the rebound processes of hard particles, taking into account the particle kinetic energy, van der Waals forces, and RH-dependent capillary forces. For low RH values, the hard-particle model explained the diameter-dependent rebound behavior for all studied SOMs. For elevated RH, however, the experimental observations deviated from the model predictions. On the basis of the calibration experiments using sucrose particles as well as a comparison between the observations and the predictions of the hard-particle model, the interpretation is made that a semisolid-to-liquid transition occurred at elevated RH. Material softening, increased adhesion, or a combination of the two implied the action of additional modes of energy relaxation that were not included in the hard-particle model. The RH threshold for the semisolid-to-liquid phase transition was 40% RH for isoprene SOM, 70% for toluene SOM, and 70% for α-pinene SOM. A correlation between the rebound fraction and the hygroscopic growth factor G was demonstrated, implying that absorbed water volume was a dominant governing factor of the semisolid-to-liquid transition for the studied classes of SOM. Simple heuristic rules based on G of 1.15 for the semisolid-to-liquid phase transition could be used for prognostication of the SOM phase in modeling applications at 298 K. With respect to atmospheric processes, the

Rebound and disinvestment effects in refined oil consumption and supply resulting from an increase in energy efficiency in the Scottish commercial transport sector

International Nuclear Information System (INIS)

Anson, Sam; Turner, Karen

2009-01-01

In this paper, we use an energy-economy-environment computable general equilibrium (CGE) model of the Scottish economy to examine the impacts of an exogenous increase in energy augmenting technological progress in the domestic commercial Transport sector on the supply and use of energy. We focus our analysis on Scottish refined oil, as the main type of energy input used in commercial transport activity. We find that a 5% increase in energy efficiency in the commercial Transport sector leads to rebound effects in the use of oil-based energy commodities in all time periods, in the target sector and at the economy-wide level. However, our results also suggest that such an efficiency improvement may cause a contraction in capacity in the Scottish refined oil supply sector. This 'disinvestment effect' acts as a constraint on the size of rebound effects. However, the magnitude of rebound effects and presence of the disinvestment effect in the simulations conducted here are sensitive to the specification of key elasticities of substitution in the nested production function for the target sector, particularly the substitutability of energy for non-energy intermediate inputs to production.

Rebound and disinvestment effects in refined oil consumption and supply resulting from an increase in energy efficiency in the Scottish commercial transport sector

Energy Technology Data Exchange (ETDEWEB)

Anson, Sam [Transport Analytical Services, Scottish Government, Victoria Quay, Edinburgh, EH6 6QQ (United Kingdom); Turner, Karen [Department of Economics, University of Strathclyde, Sir William Duncan Building, 130 Rottenrow, Glasgow G4 0GE (United Kingdom)

2009-09-15

In this paper, we use an energy-economy-environment computable general equilibrium (CGE) model of the Scottish economy to examine the impacts of an exogenous increase in energy augmenting technological progress in the domestic commercial Transport sector on the supply and use of energy. We focus our analysis on Scottish refined oil, as the main type of energy input used in commercial transport activity. We find that a 5% increase in energy efficiency in the commercial Transport sector leads to rebound effects in the use of oil-based energy commodities in all time periods, in the target sector and at the economy-wide level. However, our results also suggest that such an efficiency improvement may cause a contraction in capacity in the Scottish refined oil supply sector. This 'disinvestment effect' acts as a constraint on the size of rebound effects. However, the magnitude of rebound effects and presence of the disinvestment effect in the simulations conducted here are sensitive to the specification of key elasticities of substitution in the nested production function for the target sector, particularly the substitutability of energy for non-energy intermediate inputs to production. (author)

Characteristics of activated carbon remove sulfur particles against smog.

Science.gov (United States)

Ge, Shengbo; Liu, Zhenling; Furuta, Yuzo; Peng, Wanxi

2017-09-01

Sulfur particles, which could cause diseases, were the main powder of smog. And activated carbon had the very adsorption characteristics. Therefore, five sulfur particles were adsorbed by activated carbon and were analyzed by FT-IR. The optimal adsorption time were 120 min of Na 2 SO 3 , 120 min of Na 2 S 2 O 8 , 120 min of Na 2 SO 4 , 120 min of Fe 2 (SO 4 ) 3 and 120 min of S. FT-IR spectra showed that activated carbon had the eight characteristic absorption of S-S stretch, H 2 O stretch, O-H stretch, -C-H stretch, conjugated C 000000000000 000000000000 000000000000 111111111111 000000000000 111111111111 000000000000 000000000000 000000000000 O stretch or CC stretch, CH 2 bend, C-O stretch and acetylenic C-H bend vibrations at 3850 cm -1 , 3740 cm -1 , 3430 cm -1 , 2920 cm -1 , 1630 cm -1 , 1390 cm -1 , 1110 cm -1 and 600 cm -1 , respectively. For Na 2 SO 3 , the peaks at 2920 cm -1 , 1630 cm -1 , 1390 cm -1 and 1110 cm -1 achieved the maximum at 20 min. For Na 2 S 2 O 8 , the peaks at 3850 cm -1 , 3740 cm -1 and 2920 cm -1 achieved the maximum at 60 min. The peaks at 1390 cm -1 , 1110 cm -1 and 600 cm -1 achieved the maximum at 40 min. For Na 2 SO 4 , the peaks at 3430 cm -1 , 2920 cm -1 , 1630 cm -1 , 1390 cm -1 , 1110 cm -1 and 600 cm -1 achieved the maximum at 60 min. For Fe 2 (SO 4 ) 3 , the peaks at 1390 cm -1 , 1110 cm -1 and 600 cm -1 achieved the maximum at 20 min. For S, the peaks at 1630 cm -1 , 1390 cm -1 and 600 cm -1 achieved the maximum at 120 min. It provided that activated carbon could remove sulfur particles from smog air to restrain many anaphylactic diseases.

Elutriation characteristics of fine particles from bubbling fluidized bed incineration for sludge cake treatment.

Science.gov (United States)

Chang, Yu-Min; Chou, Chih-Mei; Su, Kuo-Tung; Hung, Chao-Yang; Wu, Chao-Hsiung

2005-01-01

In this study, measurements of elutriation rate were carried out in a bench scale bubbling fluidized bed incinerator, which was used to combust sludge cake. The particle size distribution and ignition loss were analyzed to study the elutriation characteristics of bubbling fluidized bed incineration. Drawn from the experimental data, the elutriation rate constant K(i)* for fine particles were obtained and correlated with parameters. It was found that most of the solid particles (about 95%) elutriated came from the fluidized medium (inorganic matters), but few came from unburned carbon particles or soot (about 5%). Finally, this paper lists a comparison of K(i)* between this study and the published prediction equations derived or studied in non-incineration modes of fluidized bed. A new and modified correlation is proposed here to estimate the elutriation rate of fine particles emitted from a bubbling fluidized bed incinerator. Primary operation variables (superficial gas velocity and incineration temperature) affecting the elutriation rate are also discussed in the paper.

Characteristic lesions in mouse retina irradiated with accelerated iron particles

International Nuclear Information System (INIS)

Malachowski, M.J.; Philpott, D.E.; Corbett, R.L.; Tobias, C.A.

1981-01-01

A program is underway to determine the radiation hazards of HZE particles using the Bevalac, a heavy-ion accelerator at LBL. Our earlier work with helium, carbon, neon, and argon particles, and exposure to rats to HZE particles in space flight demonstrated some deleterious biological effects. TEM studies have shown that some visual cells were missing and dislocated; these were termed channel lesions. Recently obtained is evidence that a single iron HZE particle may affect a series of cells. Mice were irradiated with 0.1, 0.3, 1, 10, or 25 rad of 590 MeV/amu initial kinetic energy iron particles in groups of 10 animals per dose point. Irradiated and control animals were sacrificed at intervals from one week to two years postirradiation. The eye samples were dehydrated, critical points dried with freon, fractured, and Au-Pd coated for SEM, or plastic embedded, sectioned, and stained for TEM. Additionally, dry fractured samples viewed with the SEM were embedded in plastic, sectioned, and stained for the TEM. Characteristic tunnel shaped lesions were observed with the SEM. Stereo pairs showed tunnels of various lengths up to 100 μm. Light microscopy of serially cut sections from the same material had vacuoles (V) extending the same length. TEM of the same specimen and specimens prepared only for TEM exhibited large vacuoles, greater than or equal to 2 μm, in the inner segment (IS) and outer segment (OS) layers. Severe membrane disruption was found bordering the vacuoles and gross nuclear degeneration (ND) and loose tissue (LT) were seen in the outer nuclear layer (ONL). The number of lesions increased with increasing dose. Microscopy of the control retina failed to demonstrate similar lesions

Hydrophobic and optical characteristics of graphene and graphene oxide films transferred onto functionalized silica particles deposited glass surface

Science.gov (United States)

Yilbas, B. S.; Ibrahim, A.; Ali, H.; Khaled, M.; Laoui, T.

2018-06-01

Hydrophobic and optical transmittance characteristics of the functionalized silica particles on the glass surface prior and after transfer of graphene and graphene oxide films on the surface are examined. Nano-size silica particles are synthesized and functionalized via chemical grafting and deposited onto a glass surface. Graphene film, grown on copper substrate, was transferred onto the functionalized silica particles surface through direct fishing method. Graphene oxide layer was deposited onto the functionalized silica particles surface via spin coating technique. Morphological, hydrophobic, and optical characteristics of the functionalized silica particles deposited surface prior and after graphene and graphene oxide films transfer are examined using the analytical tools. It is found that the functionalized silica particles are agglomerated at the surface forming packed structures with few micro/nano size pores. This arrangement gives rise to water droplet contact angle and contact angle hysteresis in the order of 163° and 2°, respectively, and remains almost uniform over the entire surface. Transferring graphene and depositing graphene oxide films over the functionalized silica particles surface lowers the water droplet contact angle slightly (157-160°) and increases the contact angle hysteresis (4°). The addition of the graphene and graphene oxide films onto the surface of the deposited functionalized silica particles improves the optical transmittance.

Rate on the rebound of films, strategic design and results; Tasa de rechazo de peliculas, diseno de estrategias y resultados

Energy Technology Data Exchange (ETDEWEB)

Guibelalde, E.; Fernandez, J.M.; Ramirez, R.; Canevaro, R.; Vano, E. [Catedra de Fisica Medica. Departamento de Radiologia. Universidad Complutense. Madrid (Spain)

1998-12-31

The present work pretends to identify the diagnostic tests of greatest rate on the rebound and to analyze their causes comparing them with the reference values obtained in the University Hospital `San Carlos` study in 1993. Equally is looking for contributing with criterions and strategies for the implantation of a responsible system of information caption. The control of the rate on rebound of radiographic plates is fundamental for the quality control programs feedback. The results emitted by this study confirm the utility to the advantage of this type of global indicators for the quality control programs and contribute reducing collective doses, since the improvement of medical diagnostic and diminishing the operation costs of the inputs utilized. It is emphasized the importance what had to introduce at the personnel which participate in the system to obtain fitted results. (Author)

Characteristics of individual particles in Beijing before, during and after the 2014 APEC meeting

Science.gov (United States)

Xu, Zhongjun; Shan, Wei; Qi, Tao; Gao, Jian

2018-05-01

To understand the characteristics of individual aerosol particles as well as the effects of emission control measures on the air quality in Beijing before, during and after the 2014 APEC meeting, aerosol samples collected in Beijing from Oct. 8 to Nov. 24 were investigated by a scanning electron microscopy (SEM) coupled with an energy-dispersive X-ray (EDX). Individual particles were classified into fly ash, ammonium sulfate, carbonaceous particle, tar ball, soot aggregates, Fe/Ti oxide, Ca/Mg carbonate, calcium sulfate and aluminosilicates/quartz. The results showed that PM0.5-1.0 was predominant in aerosol particles while PM2.5-10 was the fewest in aerosol particles. Soot aggregates and carbonaceous particles mainly located in the size range of 0.5-2.5 μm and mineral particles were dominant in the size range of 2.5-10 μm. The tough emission control measures taken by the local government greatly improved the air quality. Reducing vehicles on the roads substantially decreased the amount of soot aggregates, and restricting coal combustion decreased the amount of tar ball during the APEC meeting. The concentrations of carbonaceous and mineral particles abated probably owing to the control on VOCs emission, and water spray and demolition layoff, respectively, during the APEC meeting.

Harvard Bounce Apparatus GoAmazon 2014/15 Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Bateman, Adam [Harvard Univ., Cambridge, MA (United States); Martin, Scott T. [Harvard Univ., Cambridge, MA (United States)

2016-05-01

The effect of relative humidity (RH) on the physical state of particulate matter during the GoAmazon 2014/15 campaign was investigated through the use of particle rebound (or lack thereof) during impaction. The physics governing particle rebound have been previously modeled and can be attributed to the surface and material properties. The physical state of secondary organic material is regulated by several factors, including the local RH, the recent RH history in the case of hysteresis, and chemical composition. Across the range of atmospheric RH, hygroscopic water uptake can occur and transitions from higher to lower viscosity phases are possible. By varying the particulate matter water content and observing particle rebound as a function of RH, the phase state of the organic material under investigation can be determined. Custom-made impactors were employed to study the effects of RH (up to 95%) on the particle physical state. Results inferred from the particle rebound measurements indicate that, under ambient conditions (RH >80%), particulate matter in Amazonia can be considered in a liquid phase state. However, during certain time periods, a fraction (10 to 30%) of particulate matter is found to rebound during the highest RH conditions, which indicates the presence of hydrophobic particles. The source of the hydrophobic particulates appears to be anthropogenic, from either biomass burning or the Manaus plume.

Osteonecrosis of the Jaw and Rebound Hypercalcemia in Young People Treated With Denosumab for Giant Cell Tumor of Bone.

Science.gov (United States)

Uday, Suma; Gaston, Czar Louie; Rogers, Luke; Parry, Michael; Joffe, Johnathan; Pearson, John; Sutton, David; Grimer, Robert; Högler, Wolfgang

2018-02-01

Denosumab, an inhibitor of receptor activator of nuclear factor κ-B ligand, is an approved treatment of giant cell tumor of bone (GCTB) in adults and "skeletally mature" adolescents. Safety concerns include oversuppression of bone remodelling, with risk of osteonecrosis of the jaw (ONJ) and atypical femur fractures during treatment in adults and rebound hypercalcemia after treatment cessation in children. To date, ONJ has never been reported in children or adolescents. To describe serious adverse effects during and following high-dose denosumab therapy in GCTB patients. Two adolescents (14 and 15 years) and a young adult (40 years) received fixed-dose denosumab for GCTB for 1.3 to 4 years (cumulative dose, 47 to 98 mg/kg), which was stopped because of development of ONJ in one adolescent and bilateral femoral cortical stress reactions in the young adult. All three patients developed rebound hypercalcemia with acute kidney injury 5.5 to 7 months after denosumab cessation. The ONJ necessitated surgical debridement. Rebound hypercalcemia (serum calcium, 3.1 to 4.3 mmol/L) was unresponsive to hyperhydration alone, requiring repeated doses of calcitonin or intravenous bisphosphonate treatment. Hypercalcemia recurred in two patients within 4 weeks, with normal serum calcium profiles thereafter. All patients were naive to chemotherapy, radiotherapy, bisphosphonates, and corticosteroids and were metastases free, confirming the causative role of denosumab in these complications. These suppression-release effects of high-dose denosumab on bone remodeling raise questions about safety of fixed dosing and treatment duration. In young people, weight-adjusted dosing and safety monitoring during and after antiresorptive therapy is required. Copyright © 2017 Endocrine Society

Experimental study of the form of “hot” steel particles on the ignition characteristics of liquid fuels

Directory of Open Access Journals (Sweden)

Zakharevich Arkadiy V.

2015-01-01

Full Text Available The results of an experimental study of laws governing the ignition of liquid propellants (kerosene, diesel fuel and petroleum residue by the single spherical steel particle heated to high temperatures are presented. Is carried out the comparison of the ignition delay times of the investigated flammable substances by the particles in the sphere and disk forms. It is established that the particle shape does not exert a substantial influence on the ignition process characteristics.

Platelet rebound effect of alcohol withdrawal and wine drinking in rats. Relation to tannins and lipid peroxidation.

Science.gov (United States)

Ruf, J C; Berger, J L; Renaud, S

1995-01-01

We investigated in rats fed a purified diet for 2 and 4 months whether wine drinking was associated with the rebound effect on thrombin-induced platelet aggregation observed after alcohol withdrawal. With 6% ethanol drinking or its equivalent in red or white wine, platelet aggregation was reduced similarly by 70% when the animals drank the alcoholic beverages up to the venipuncture. Depriving the rats of alcoholic beverages for 18 hours was associated with an increase in the platelet response of 124% in those receiving 6% ethanol, of 46% with white wine but a decrease of 59% in those with red wine. The protective effect of red wine on platelets could be reproduced by tannins (procyanidins) extracted from grape seeds or red wine and added to 6% ethanol, but not by glycerol or wine without alcohol. That was related to inhibition of the alcohol-induced lipid peroxidation as shown by the lowering of conjugated dienes, lipid peroxides, and the increase in vitamin E in plasma. Owing to tannins, the platelets of rats drinking red wine did not exhibit the rebound effect observed hours after alcohol drinking, eventually associated with sudden death and stroke in humans.

Characteristics of SME biodiesel-fueled diesel particle emissions and the kinetics of oxidation.

Science.gov (United States)

Jung, Heejung; Kittelson, David B; Zachariah, Michael R

2006-08-15

Biodiesel is one of the most promising alternative diesel fuels. As diesel emission regulations have become more stringent, the diesel particulate filter (DPF) has become an essential part of the aftertreatment system. Knowledge of kinetics of exhaust particle oxidation for alternative diesel fuels is useful in estimating the change in regeneration behavior of a DPF with such fuels. This study examines the characteristics of diesel particulate emissions as well as kinetics of particle oxidation using a 1996 John Deere T04045TF250 off-highway engine and 100% soy methyl ester (SME) biodiesel (B100) as fuel. Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%. Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3times greater frequency factor and approximately 6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825 degrees C. The faster oxidation kinetics should facilitate regeneration when used with a DPF.

Characteristic Studies of Micron Zinc Particle Hydrolysis in a Fixed Bed Reactor

Directory of Open Access Journals (Sweden)

Lv Ming

2015-09-01

Full Text Available Zinc fuel is considered as a kind of promising energy sources for marine propeller. As one of the key steps for zinc marine energy power system, zinc hydrolysis process had been studied experimentally in a fixed bed reactor. In this study, we focus on the characteristics of micron zinc particle hydrolysis. The experimental results suggested that the steam inner diffusion is the controlling step of accumulative zinc particles hydrolysis reaction at a relative lower temperature and a relative higher water partial pressure. In other conditions, the chemical reaction kinetics was the controlling step. And two kinds of chemical reaction kinetics appeared in experiments: the surface reaction and the gas-gas reaction. The latter one occurs usually for larger zinc particles and high reaction temperature. Temperature seems to be one of the most important parameters for the dividing of different reaction mechanisms. Several parameters of the hydrolysis process including heating rate, water partial pressure, the particle size and temperature were also studied in this paper. Results show that the initial reaction temperature of zinc hydrolysis in fixed bed is about 410°C. And the initial reaction temperature increases as the heating rate increases and as the water partial pressure decreases. The total hydrogen yield increases as the heating rate decreases, as the water partial pressure increases, as the zinc particle size decreases, and as the reaction temperature increases. A hydrogen yield of more than 81.5% was obtained in the fixed bed experiments.

Magnetic characteristics of ultrafine Fe particles reduced from uniform iron oxide particles

Science.gov (United States)

Bridger, K.; Watts, J.; Tadros, M.; Xiao, Gang; Liou, S. H.; Chien, C. L.

1987-04-01

Uniform, cubic 0.05-μm iron oxide particles were formed by forced hydrolysis of ferric perchlorate. These particles were reduced to α-Fe by heating in hydrogen at temperatures between 300 and 500 °C. The effect of reduction temperature and various prereduction treatments on the microstructure of the iron particles will be discussed. Complete reduction to α-Fe was established by 57Fe Mössbauer spectroscopy and x-ray diffraction. Magnetic measurements on epoxy and polyurethane films containing these particles with various mass fractions gave coercivities as high as 1000 Oe. The relationship between the magnetic measurements and the microstructure will be discussed. Na2SiO3 is found to be the best coating material for the process of reducing iron oxide particles to iron.

Predicting the Agglomeration of Cohesive Particles in a Gas-Solid Flow and its Effect on the Solids Flow

Science.gov (United States)

Kellogg, Kevin; Liu, Peiyuan; Lamarche, Casey; Hrenya, Christine

2017-11-01

In flows of cohesive particles, agglomerates will readily form and break. These agglomerates are expected to complicate how particles interact with the surrounding fluid in multiphase flows, and consequently how the solids flow. In this work, a dilute flow of particles driven by gas against gravity is studied. A continuum framework, composed of a population balance to predict the formation of agglomerates, and kinetic-theory-based balances, is used to predict the flow of particles. The closures utilized for the birth and death rates due to aggregation and breakage in the population balance take into account how the impact velocity (the granular temperature) affects the outcome of a collision as aggregation, rebound, or breakage. The agglomerate size distribution and solids velocity predicted by the continuum framework are compared to discrete element method (DEM) simulations, as well to experimental results of particles being entrained from the riser of a fluidized bed. Dow Corning Corporation.

Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

International Nuclear Information System (INIS)

Poellaenen, R.

2002-05-01

In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has been higher

Characteristics of 'hot particles' from the Chernobyl radioactive fallout and some comments on the relevant radiological risk

International Nuclear Information System (INIS)

Jaracz, P.; Mirowski, S.; Piasecki, E.; Wilhelmi, Z.

2004-01-01

Paper reviews some radiative characteristics of 'hot particles' (HP) - a particulate fraction of the Chernobyl fallout. The work is based mostly on results of HP investigations of the Warsaw group. A classification of hot particles in their γ activity contents as well as some suggestions about possible mechanisms of their formation are provided. A comparison between activities of the Chernobyl hot particles and the ones from nuclear weapon tests of the early 60-ties is made. Some comments on health detriment caused by HPs are included. (author)

Charged particle emission effects on the characteristics of glow discharges with oscillating electrons

CERN Document Server

Nikulin, S P

2001-01-01

One discusses the effect of selection of charged particles on conditions to maintain and the characteristics of a glow discharge with oscillating electrons. It is shown that there is a pressure dependent optimal level of ion selection when the energy efficiency of ion source reaches its maximum value. It is determined that departure of fast ionizing electrons affects negatively the discharge maintenance wile emission of slow plasma electrons may promote maintenance of a discharge high current shape. It is shown that high efficient electron emission without violation of a discharge stability may take place in a magnetic field due to different nature of spatial distributions of fast and slow particles in discharges with electron oscillation

Energy requirements of consumption: Urban form, climatic and socio-economic factors, rebounds and their policy implications

International Nuclear Information System (INIS)

Wiedenhofer, Dominik; Lenzen, Manfred; Steinberger, Julia K.

2013-01-01

Household consumption requires energy to be used at all stages of the economic process, thereby directly and indirectly leading to environmental impacts across the entire production chain. The levels, structure and determinants of energy requirements of household consumption therefore constitute an important avenue of research. Incorporating the full upstream requirements into the analysis helps to avoid simplistic conclusions which would actually only imply shifts between consumption categories without taking the economy wide effects into account. This paper presents the investigation of the direct and indirect primary energy requirements of Australian households, contrasting urban, suburban and rural consumption patterns as well as inter- and intra-regional levels of inequality in energy requirements. Furthermore the spatial and socio-economic drivers of energy consumption for different categories of energy requirements are identified and quantified. Conclusions regarding the relationships between energy requirements, household characteristics, urban form and urbanization processes are drawn and the respective policy implications are explored. - Highlights: • We statistically analyze the energy requirements of consumption in Australia. • Contrasting urban/suburban/rural consumption patterns and spatial inequality. • Energy requirements are influenced by urban form, income and demographics. • Urban households require less direct energy, but their total consumption is higher. • Significant rebound effects can be expected when direct energy use is decreased

Influence of the RF electrode cleanliness on plasma characteristics and dust-particle generation in methane dusty plasmas

Science.gov (United States)

Géraud-Grenier, I.; Desdions, W.; Faubert, F.; Mikikian, M.; Massereau-Guilbaud, V.

2018-01-01

The methane decomposition in a planar RF discharge (13.56 MHz) leads both to a dust-particle generation in the plasma bulk and to a coating growth on the electrodes. Growing dust-particles fall onto the grounded electrode when they are too heavy. Thus, at the end of the experiment, the grounded electrode is covered by a coating and by fallen dust-particles. During the dust-particle growth, the negative DC self-bias voltage (VDC) increases because fewer electrons reach the RF electrode, leading to a more resistive plasma and to changes in the plasma chemical composition. In this paper, the cleanliness influence of the RF electrode on the dust-particle growth, on the plasma characteristics and composition is investigated. A cleanliness electrode is an electrode without coating and dust-particles on its surface at the beginning of the experiment.

Microwave characteristics of low density flaky magnetic particles

International Nuclear Information System (INIS)

Wenqiang, Zhang; Deyuan, Zhang; Jun, Cai

2013-01-01

Diatomite coated with thin Fe films were obtained by the Chemical Vapor Deposition process. The resultant Fe-coated flaky diatomite particles had low densities (2.7–4.0 g/cm 3 ) and high saturation magnetization (93–157 emu/g). Annealing treatment led to grain growth and an increased saturation magnetization. The high frequency properties of the composites consisting of Fe-coated flaky diatomite particles and wax were investigated. The permittivity and permeability increased with increasing flaky magnetic particles content in the composite and increasing the Fe weight percentage of the particles. The reflection loss of the composite was found dependent on the absorber material thickness, wax:flaky magnetic particles ratios, the Fe content, as well as the annealing treatment. At a thickness of 1 mm, the composite records a minimum reflection loss of −18 dB at 6 GHz. - Highlights: ► We synthesize the flaky magnetic particles with the diatomite as template. ► The flaky magnetic particles coating layers are constituted by α-Fe. ► The flaky magnetic particles have good static magnetic properties. ► The flaky magnetic particles are a kind light weight high performance microwave absorber

Microwave characteristics of low density flaky magnetic particles

Energy Technology Data Exchange (ETDEWEB)

Wenqiang, Zhang, E-mail: zwqzwqzwqzwq@126.com [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China); College of Engineering, China Agricultural University, Beijing 100083 (China); Deyuan, Zhang [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China); Jun, Cai, E-mail: jun_cai@buaa.edu.cn [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China)

2013-04-15

Diatomite coated with thin Fe films were obtained by the Chemical Vapor Deposition process. The resultant Fe-coated flaky diatomite particles had low densities (2.7–4.0 g/cm{sup 3}) and high saturation magnetization (93–157 emu/g). Annealing treatment led to grain growth and an increased saturation magnetization. The high frequency properties of the composites consisting of Fe-coated flaky diatomite particles and wax were investigated. The permittivity and permeability increased with increasing flaky magnetic particles content in the composite and increasing the Fe weight percentage of the particles. The reflection loss of the composite was found dependent on the absorber material thickness, wax:flaky magnetic particles ratios, the Fe content, as well as the annealing treatment. At a thickness of 1 mm, the composite records a minimum reflection loss of −18 dB at 6 GHz. - Highlights: ► We synthesize the flaky magnetic particles with the diatomite as template. ► The flaky magnetic particles coating layers are constituted by α-Fe. ► The flaky magnetic particles have good static magnetic properties. ► The flaky magnetic particles are a kind light weight high performance microwave absorber.

Visualizing test on the pass-through and collision characteristics of coarse particles in a double blade pump

Directory of Open Access Journals (Sweden)

Minggao Tan

2018-01-01

Full Text Available As the key equipment in deep ocean mining, the slurry pump suffers from wear and blocking problems. In this paper, high-speed photography technique is applied to track the movement rule of single particle of the coarse particle solid–liquid two-phase flow in a double blade slurry pump. The influences of particle diameter and particle density on the pass-through and collision characteristics of particles are analyzed as well. The results show that the average of the passing pump time first decreases and then increases when the particle diameter increases. The average of the passing pump time decreases by 22.7%, when the particle density increases from 1.09 g/cm3 to 1.75 g/cm3. Besides, the particle density has great influence on the location where the particle hits the tongue. Most particles of 1.09 g/cm3 hit the tongue on the left side, while collision location of particles of 1.75 g/cm3 is mainly on the top and at the right side of the tongue. The research can provide a basis for the optimization design of slurry pump in deep ocean mining system.

Renewable energy rebound effect?: Estimating the impact of state renewable energy financial incentives on residential electricity consumption

Science.gov (United States)

Stephenson, Beth A.

Climate change is a well-documented phenomenon. If left unchecked greenhouse gas emissions will continue global surface warming, likely leading to severe and irreversible impacts. Generating renewable energy has become an increasingly salient topic in energy policy as it may mitigate the impact of climate change. State renewable energy financial incentives have been in place since the mid-1970s in some states and over 40 states have adopted one or more incentives at some point since then. Using multivariate linear and fixed effects regression for the years 2002 through 2012, I estimate the relationship between state renewable energy financial incentives and residential electricity consumption, along with the associated policy implications. My hypothesis is that a renewable energy rebound effect is present; therefore, states with renewable energy financial incentives have a higher rate of residential electricity consumption. I find a renewable energy rebound effect is present in varying degrees for each model, but the results do not definitively indicate how particular incentives influence consumer behavior. States should use caution when adopting and keeping renewable energy financial incentives as this may increase consumption in the short-term. The long-term impact is unclear, making it worthwhile for policymakers to continue studying the potential for renewable energy financial incentives to alter consumer behavior.

Characteristics of Fine Particles in an Urban Atmosphere—Relationships with Meteorological Parameters and Trace Gases

Science.gov (United States)

Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

2016-01-01

Atmospheric fine particles (diameter industrial emissions. To reveal the characteristics of fine particles in an industrial city of a developing country, two-year measurements of particle number size distribution (15.1 nm–661 nm), meteorological parameters, and trace gases were made in the city of Wuhan located in central China from June 2012 to May 2014. The annual average particle number concentrations in the nucleation mode (15.1 nm–30 nm), Aitken mode (30 nm–100 nm), and accumulation mode (100 nm–661 nm) reached 4923 cm−3, 12193 cm−3 and 4801 cm−3, respectively. Based on Pearson coefficients between particle number concentrations and meteorological parameters, precipitation and temperature both had significantly negative relationships with particle number concentrations, whereas atmospheric pressure was positively correlated with the particle number concentrations. The diurnal variation of number concentration in nucleation mode particles correlated closely with photochemical processes in all four seasons. At the same time, distinct growth of particles from nucleation mode to Aitken mode was only found in spring, summer, and autumn. The two peaks of Aitken mode and accumulation mode particles in morning and evening corresponded obviously to traffic exhaust emissions peaks. A phenomenon of “repeated, short-lived” nucleation events have been created to explain the durability of high particle concentrations, which was instigated by exogenous pollutants, during winter in a case analysis of Wuhan. Measurements of hourly trace gases and segmental meteorological factors were applied as proxies for complex chemical reactions and dense industrial activities. The results of this study offer reasonable estimations of particle impacts and provide references for emissions control strategies in industrial cities of developing countries. PMID:27517948

Characteristics of particle beam acceleration on KUMS tandem electrostatic accelerator 5SDH-2

OpenAIRE

谷池, 晃; 古山, 雄一; 北村, 晃

2006-01-01

The KUMS tandem electrostatic accelerator, 5SDH-2, was installed in 1996. Ten years have passed since it installed and we obtain some data for accelerator operations. We report the particle beam characteristics such as relation between beam species and switcher magnet current, and dependence of ion charge fraction on stripper gas thickness. We also try to generate nitrogen ion beams, and low energy ion beams.

Adiposity rebound and the development of metabolic syndrome.

Science.gov (United States)

Koyama, Satomi; Ichikawa, Go; Kojima, Megumi; Shimura, Naoto; Sairenchi, Toshimi; Arisaka, Osamu

2014-01-01

The age of adiposity rebound (AR) is defined as the time at which BMI starts to rise after infancy and is thought to be a marker of later obesity. To determine whether this age is related to future occurrence of metabolic syndrome, we investigated the relationship of the timing of AR with metabolic consequences at 12 years of age. A total of 271 children (147 boys and 124 girls) born in 1995 and 1996 were enrolled in the study. Serial measurements of BMI were conducted at the ages of 4 and 8 months and 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 years, based on which age of AR was calculated. Plasma lipids and blood pressure were measured at 12 years of age. An earlier AR (high-density lipoprotein cholesterol in boys and elevated apolipoprotein B in girls at 12 years of age. The earlier AR was also related to elevated blood pressure in boys. This longitudinal population-based study indicates that children who exhibit AR at a younger age are predisposed to future development of metabolic syndrome. Therefore, monitoring of AR may be an effective method for the early identification of children at risk for metabolic syndrome.

Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

Energy Technology Data Exchange (ETDEWEB)

Poellaenen, R

2002-05-01

In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has

Dynamics of particle loading in deep-bed filter. Transport, deposition and reentrainment

Directory of Open Access Journals (Sweden)

Przekop Rafał

2016-09-01

Full Text Available Deep bed filtration is an effective method of submicron and micron particle removal from the fluid stream. There is an extensive body of literature regarding particle deposition in filters, often using the classical continuum approach. However, the approach is not convenient for studying the influence of particle deposition on filter performance (filtration efficiency, pressure drop when non-steady state boundary conditions have to be introduced. For the purposes of this work the lattice-Boltzmann model describes fluid dynamics, while the solid particle motion is modeled by the Brownian dynamics. For aggregates the effect of their structure on displacement is taken into account. The possibility of particles rebound from the surface of collector or reentrainment of deposits to fluid stream is calculated by energy balanced oscillatory model derived from adhesion theory. The results show the evolution of filtration efficiency and pressure drop of filters with different internal structure described by the size of pores. The size of resuspended aggregates and volume distribution of deposits in filter were also analyzed. The model enables prediction of dynamic filter behavior. It can be a very useful tool for designing filter structures which optimize maximum lifetime with the acceptable values of filtration efficiency and pressure drop.

Seasonal variations in physical characteristics of aerosol particles at the King Sejong Station, Antarctic Peninsula

Science.gov (United States)

Kim, Jaeseok; Yoon, Young Jun; Gim, Yeontae; Kang, Hyo Jin; Choi, Jin Hee; Park, Ki-Tae; Lee, Bang Yong

2017-11-01

Seasonal variability in the physical characteristics of aerosol particles sampled from the King Sejong Station in the Antarctic Peninsula was investigated over the period between March 2009 and February 2015. Clear seasonal cycles for the total particle concentration (CN) were observed. The mean monthly concentration of particles larger than 2.5 nm (CN2.5) was highest during the austral summer, with an average value of 1080.39 ± 595.05 cm-3, and lowest during the austral winter, with a mean value of 197.26 ± 71.71 cm-3. The seasonal patterns in the concentrations of cloud condensation nuclei (CCN) and CN coincide, with both concentrations being at a minimum in winter and maximum in summer. The measured CCN spectra were approximated by fitting a power-law function relating the number of CCN for a given supersaturation (SS) to each SS value, with fitting coefficients C and kT. The values for C varied from 6.35 to 837.24 cm-3, with a mean of 171.48 ± 62.00 cm-3. The values for kT ranged from 0.07 to 2.19, with a mean of 0.41 ± 0.10. In particular, the kT values during the austral summer were higher than those during the winter, indicating that aerosol particles are more sensitive to SS changes during summer. Furthermore, the annual mean hygroscopicity parameter, κ, was estimated as 0.15 ± 0.05, for a SS of 0.4 %. The effects of the origin and pathway travelled by the air mass on the physical characteristics of the aerosol particles were also determined. The modal diameter of aerosol particles originating in the South Pacific Ocean showed a seasonal variation varying from 0.023 µm in winter to 0.034 µm in summer for the Aitken mode, and from 0.086 µm in winter to 0.109 µm in summer for the accumulation mode.

Counterintuitive publicity and the rebound effect A publicidade contra-intuitiva e o efeito ricochete

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Francisco Leite

2008-11-01

Full Text Available Counterintuitive publicity and the rebound effect — This paper shares with the reader some conceptual ideas of counterintuitive advertising, observing its possible effects on the reevaluation and deconstruction of beliefs and social stereotypes in the cognitive make-up of the viewer. The ironic rebound effect is singled out among the probable reflexes, according to the theory propounded by Daniel M. Wegner. This theory is applied taking as an example Fiat's commercial "The Driver", which was part of an advertising campaign in Brazil called "Review your concepts" to introduce its new Palio 2002 car model. The authors are currently engaged in a laboratory experiment to measure the above described theory in a consistent manner. O propósito deste artigo é compartilhar com o leitor algumas noções conceituais de publicidade contra-intuitiva e observar seus possíveis efeitos na reavaliação, desconstrução de crenças e estereótipos sociais, na estrutura cognitiva do indivíduo receptor. Destaca-se entre os reflexos provavelmente gerados o irônico efeito ricochete, segundo a teoria desenvolvida por Daniel M. Wegner. A aplicação para se discutir o cruzamento da narrativa contra-intuitiva e o efeito ricochete será, neste primeiro momento, pela exemplificação do filme Motorista, peça integrante da campanha publicitária da Fiat do Brasil "Reveja seus conceitos", para o lançamento do automóvel Palio 2002. Um experimento laboratorial está sendo desenvolvido pelos autores para se mensurar de maneira consistente a apresentação teórico-conceitual exposta.

A 14-day regimen of esomeprazole 20 mg/day for frequent heartburn: durability of effects, symptomatic rebound, and treatment satisfaction.

Science.gov (United States)

Peura, David; Le Moigne, Anne; Pollack, Charles; Nagy, Peter; Lind, Tore

2016-08-01

Esomeprazole 20 mg once daily has been shown to be effective for treating frequent heartburn over 14 days in subjects who are likely to self-treat with over-the-counter medications. These analyses were conducted to assess durability of effects and symptomatic rebound after cessation of treatment, treatment satisfaction, and rescue antacid use with esomeprazole 20 mg once daily for 14 days. Adults with frequent heartburn (≥ two days/week in the past four weeks) were randomly assigned to 14 days of double-blind treatment with esomeprazole 20 mg or placebo in two identical multicenter studies. All subjects entered a 1-week single-blind placebo follow-up period after treatment. The results of the primary efficacy endpoints were reported previously. The percentage of heartburn-free days during the 1-week follow-up, use of rescue antacids, and treatment satisfaction, measured with the Global Assessment Questions instrument, are described. The percentage of heartburn-free days was maintained during the 1-week follow-up period; the proportion was 43% among esomeprazole subjects in these studies, suggesting no evidence of symptomatic rebound. Rescue antacid use generally decreased compared with the run-in period in the 14-day treatment and 1-week follow-up periods. Significantly more subjects taking esomeprazole were "very satisfied" or "satisfied" with treatment versus placebo (Study 1: 78% vs. 63%, respectively, P = 0.0038; Study 2: 81% vs. 60%, respectively, P = 0.0002). Subjects who are likely to self-treat their frequent heartburn with over-the-counter medications reported satisfaction with esomeprazole 20 mg. Esomeprazole's treatment effect was maintained for ≥ one week after treatment ended, with no sign of symptomatic rebound. These trials were registered at ClinicalTrials.gov: NCT01370525; NCT01370538.

High temporal resolution in situ measurement of the effective particle size characteristics of fluvial suspended sediment.

Science.gov (United States)

Williams, N D; Walling, D E; Leeks, G J L

2007-03-01

This paper reports the use of a LISST-100 device to monitor the effective particle size characteristics of suspended sediment in situ, and at a quasi-continuous temporal resolution. The study site was located on the River Exe at Thorverton, Devon, UK. This device has not previously been utilized in studies of fluvial suspended sediment at the storm event scale, and existing studies of suspended sediment dynamics have not involved such a high temporal resolution for extended periods. An evaluation of the field performance of the instrument is presented, with respect to innovative data collection and analysis techniques. It was found that trends in the effective particle size distribution (EPSD) and degree of flocculation of suspended sediment at the study site were highly complex, and showed significant short-term variability that has not previously been documented in the fluvial environment. The collection of detailed records of EPSD facilitated interpretation of the dynamic evolution of the size characteristics of suspended sediment, in relation to its likely source and delivery and flocculation mechanisms. The influence of measurement frequency is considered in terms of its implications for future studies of the particle size of fluvial suspended sediment employing in situ data acquisition.

Chemical characteristics of fine particles emitted from different gas cooking methods

Science.gov (United States)

See, Siao Wei; Balasubramanian, Rajasekhar

Gas cooking is an important indoor source of fine particles (PM 2.5). The chemical characteristics of PM 2.5 emitted from different cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying were investigated in a domestic kitchen. Controlled experiments were conducted to measure the mass concentration of PM 2.5 and its chemical constituents (elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), metals and ions) arising from these five cooking methods. To investigate the difference in particle properties of different cooking emissions, the amount and type of food, and the heat setting on the gas stove were kept constant during the entire course of the experiments. Results showed that deep-frying gave rise to the largest amount of PM 2.5 and most chemical components, followed by pan-frying, stir-frying, boiling, and steaming. Oil-based cooking methods released more organic pollutants (OC, PAHs, and organic ions) and metals, while water-based cooking methods accounted for more water-soluble (WS) ions. Their source profiles are also presented and discussed.

Multiple side effects of Efalizumab in a Saudi female with chronic persistent psoriasis followed by severe rebound after Efalizumab discontinuation

International Nuclear Information System (INIS)

Bukhari, Iqubal A.

2007-01-01

We are reporting a case of 23-years-old Saudi female with persistent chronic plaque psoriasis who was given subcutaneous Efalizumab 0.8mg/kg/week for 14 weeks. During that period the patient developed multiple adverse reactions followed by severe rebound. The case is presented to highlight the importance of managing patients on Efalizumab carefully and closely. (author)

Alpha-particle response characteristics of CR-39

International Nuclear Information System (INIS)

Abou El-Khier, A.A.; Gaber, M.; El-Khatib, A.M.; Fawzy, M.A.

1987-01-01

The form of the response curve of the polycarbonate CR-39 for α-particles at relatively low energies has been established. The investigation included measurements of both bulk- and track-etch rates. The latter was measured as a function of α-particle energies. (author)

Mechanical and Tribological Characteristics of TIG Hardfaced Dispersive Layer by Reinforced with Particles Extruded Aluminium

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R. Dimitrova

2017-05-01

Full Text Available The article presents the results of the implemented technology for generation of hardfaced dispersive layers obtained by additive material containing reinforcing phase of non-metal particles. The wear resistant coatings are deposited on pure aluminium metal matrix by shielded gas metal-arc welding applying tungsten inert gas (TIG with extruded aluminium wire reinforced by particles as additive material. Wire filler is produced by extrusion of a pack containing metalized and plated by flux micro/nano SiC particles. The metalized particles implanting in the metal matrix and its dispersive hardfacing are realized by solid-state welding under conditions of hot plastic deformation. Tribological characteristics are studied of the hardfaced layers of dispersive reinforced material on pure aluminium metal matrix with and without flux. Hardness profiles of the hardfaced layers are determined by nanoindentation. The surface layers are studied by means of Scanning Electron Microscopy (SEM and Energy Dispersive X-ray (EDX analysis. Increase by 15-31 % of the wear resistance of the hardfaced layers and 30-40 % of their hardness was found, which is due to the implanted in the layer reinforcing phase of metalized micro/nano SiC particles.

The effects of particle size and origin of calcium carbonate on performance and ossification characteristics in broiler chicks.

Science.gov (United States)

Guinotte, F; Nys, Y; de Monredon, F

1991-09-01

The following physico-chemical characteristics of various calcium sources, differing in origin and particle size were determined: mineral composition, sieve and image analysis, apparent solubility (AS), surface area (SA), porous volume, specific gravity, and compressibility (C). The AS, SA, and C values were related more to the calcium particle size than to its origin and were higher in ground calcium sources. Calcium retention of seashells treated with phosphoric acid, oyster shells, and limestone using two particle sizes, ground or particulate, was assayed in 98 broiler chicks. Particulate marble was also tested in this experiment. Calcium retention expressed as a percentage of calcium ingestion was decreased when coarse particles of calcium were supplied in lieu of pulverized sources (40 versus 49%). An experiment with a 3 x 3 x 3 factorial arrangement of treatments were tested using 576 broiler chicks. Treatments included three calcium sources (phosphorus-treated shell, oyster shell, and marble), three particle sizes [ground (less than .15 mm), medium (.6 to 1.18 mm) and coarse (greater than 1.18 mm)] and three levels of calcium (.5,.7, and .9%) with ground limestone as a reference. Performance, tibial morphometry, breaking strength variables, and ash content were measured at 4 wk of age. Weight gain and feed conversion were ameliorated with ground particles of calcium. Cortical thickness, length of the tibia, stiffness, stress, and tibia ash were diminished when coarse particles of calcium were incorporated in the diets. Conversely, the origin of the calcium source hardly affected these criteria. Additionally, the incorporation of phosphorus-treated shells was assayed in 112 broiler chicks. Coarse particles decreased calcium retention. Consequently, ultimate stress, the modulus of elasticity, and stress were impaired. It is concluded that differences in utilization of calcium carbonate sources by the broiler chick is primarily a result of particle size rather

SIMPL: A Simplified Model-Based Program for the Analysis and Visualization of Groundwater Rebound in Abandoned Mines to Prevent Contamination of Water and Soils by Acid Mine Drainage

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Sung-Min Kim

2018-05-01

Full Text Available Cessation of dewatering following underground mine closure typically results in groundwater rebound, because mine voids and surrounding strata undergo flooding up to the levels of the decant points, such as shafts and drifts. SIMPL (Simplified groundwater program In Mine workings using the Pipe equation and Lumped parameter model, a simplified lumped parameter model-based program for predicting groundwater levels in abandoned mines, is presented herein. The program comprises a simulation engine module, 3D visualization module, and graphical user interface, which aids data processing, analysis, and visualization of results. The 3D viewer facilitates effective visualization of the predicted groundwater level rebound phenomenon together with a topographic map, mine drift, goaf, and geological properties from borehole data. SIMPL is applied to data from the Dongwon coal mine and Dalsung copper mine in Korea, with strong similarities in simulated and observed results. By considering mine workings and interpond connections, SIMPL can thus be used to effectively analyze and visualize groundwater rebound. In addition, the predictions by SIMPL can be utilized to prevent the surrounding environment (water and soil from being polluted by acid mine drainage.

Physicochemical characteristics and occupational exposure to coarse, fine and ultrafine particles during building refurbishment activities

Energy Technology Data Exchange (ETDEWEB)

Azarmi, Farhad; Kumar, Prashant, E-mail: p.kumar@surrey.ac.uk, E-mail: prashant.kumar@cantab.net; Mulheron, Mike [University of Surrey, Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences (United Kingdom); Colaux, Julien L.; Jeynes, Chris [University of Surrey, Faculty of Engineering and Physical Sciences, Ion Beam Centre (United Kingdom); Adhami, Siavash; Watts, John F. [University of Surrey, The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences (United Kingdom)

2015-08-15

Understanding of the emissions of coarse (PM{sub 10} ≤10 μm), fine (PM{sub 2.5} ≤2.5 μm) and ultrafine particles (UFP <100 nm) from refurbishment activities and their dispersion into the nearby environment is of primary importance for developing efficient risk assessment and management strategies in the construction and demolition industry. This study investigates the release, occupational exposure and physicochemical properties of particulate matter, including UFPs, from over 20 different refurbishment activities occurring at an operational building site. Particles were measured in the 5–10,000-nm-size range using a fast response differential mobility spectrometer and a GRIMM particle spectrometer for 55 h over 8 days. The UFPs were found to account for >90 % of the total particle number concentrations and <10 % of the total mass concentrations released during the recorded activities. The highest UFP concentrations were 4860, 740, 650 and 500 times above the background value during wall-chasing, drilling, cementing and general demolition activities, respectively. Scanning electron microscopy, X-ray photoelectron spectroscopy and ion beam analysis were used to identify physicochemical characteristics of particles and attribute them to probable sources considering the size and the nature of the particles. The results confirm that refurbishment activities produce significant levels (both number and mass) of airborne particles, indicating a need to develop appropriate regulations for the control of occupational exposure of operatives undertaking building refurbishment.

Visual analysis and Schmidt rebound hammer test of Taj-ul-Masajid

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A. Hussain

2017-09-01

Full Text Available Taj-ul-Masajid, literally, the crown among mosques is an embodiment of genius structural engineering located in the heart of Madhya Pradesh, Bhopal. A unique combination of the Mughal Architecture in complete stone masonry and modern day RCC work, it is a liaison between the past and the present of structural engineering. A wonder in its own right, the structure is often neglected by technicians and conservationalists alike, a satire on their ingenuity. Now, in a severely dilapidated condition, the structure is in pressing need of structural rehabilitation. The authors intend to perform in-situ Non-Destructive Testing & Evaluation (NDT&E of this structure and thereby suggest steps to better its present condition. As a first step, they’ve performed the visual analysis and Schmidt Rebound Hammer Test on the concrete portion of the structure which has been presented herein. The authors have also suggested a new approach for the verification of results obtained.

The particle size characteristics of fluvial suspended sediment in the Humber and Tweed catchments, UK

Science.gov (United States)

Walling; Owens; Waterfall; Leeks; Wass

2000-05-05

This paper presents information on the absolute (chemically-dispersed) particle size characteristics of the suspended sediment transported by rivers in the Humber and Tweed basins during the period 1994-1998. For most of the rivers, > 95% of the suspended sediment load at the time of sampling was 63 microm (i.e. sand-sized material). The sediment transported in the two basins were similar. There were, however, noticeable spatial variations in the particle size composition of suspended sediment within the study basins, which reflected the particle size of the sediment sources and their spatial variation, and the selectivity of the sediment mobilization and delivery processes. When particle size parameters were plotted against discharge, there were no significant relationships, although there was some evidence of trends varying between sites. The lack of significant relationships with discharge reflects the fact that sediment particle size is largely supply-controlled, rather than a function of flow and hydraulics. When particle size variations were examined during individual storm events, there was evidence of a pulse of coarse sediment on the rising limb of the hydrograph. This may reflect the remobilization of coarse channel bed sediment as flow velocity and shear stress increase. Finer sediment was transported subsequently during the hydrograph peak and on the falling limb. The findings reported have important implications for understanding and modelling suspended sediment, and associated contaminant, dynamics in river basins.

Application of space geodetic techniques for the determination of intraplate deformations and movements in relation with the postglacial rebound of Fennoscandia

Energy Technology Data Exchange (ETDEWEB)

Scherneck, H G; Johansson, J M; Elgered, G [Chalmers Univ. of Technology, Goeteborg (Sweden). Onsala Space Observatory

1996-04-01

This report introduces into space geodetic measurements of relative positions over distances ranging from tens to thousands of kilometers. Such measurements can routinely be carried out with repeatabilities on the order of a few millimeters. The techniques presented are Very Long Baseline Interferometry (VLBI), employing observations of radio-astronomical objects in the distant universe, and ranging measurements to satellites of the GPS, the Global Positioning System. These techniques have helped to trace plate tectonic motions. More recently, deformations within continents have been detected. We present the SWEPOS system of permanently operating GPS stations as one of the major geoscience investments starting in 1993. BIFROST (Baseline Interference for Fennoscandian Rebound Observations, Sea level, and Tectonics) is a project within SWEPOS with main purpose to detect crustal movements in Fennoscandia. First results are presented, indicating movements which generally support the notion of a dominating displacement pattern due to the postglacial rebound of Fennoscandia. However deviations exist. densification is indicated in those areas which are notable for an increased seismicity. 148 refs.

Application of space geodetic techniques for the determination of intraplate deformations and movements in relation with the postglacial rebound of Fennoscandia

International Nuclear Information System (INIS)

Scherneck, H.G.; Johansson, J.M.; Elgered, G.

1996-04-01

This report introduces into space geodetic measurements of relative positions over distances ranging from tens to thousands of kilometers. Such measurements can routinely be carried out with repeatabilities on the order of a few millimeters. The techniques presented are Very Long Baseline Interferometry (VLBI), employing observations of radio-astronomical objects in the distant universe, and ranging measurements to satellites of the GPS, the Global Positioning System. These techniques have helped to trace plate tectonic motions. More recently, deformations within continents have been detected. We present the SWEPOS system of permanently operating GPS stations as one of the major geoscience investments starting in 1993. BIFROST (Baseline Interference for Fennoscandian Rebound Observations, Sea level, and Tectonics) is a project within SWEPOS with main purpose to detect crustal movements in Fennoscandia. First results are presented, indicating movements which generally support the notion of a dominating displacement pattern due to the postglacial rebound of Fennoscandia. However deviations exist. densification is indicated in those areas which are notable for an increased seismicity. 148 refs

Seasonal variations in physical characteristics of aerosol particles at the King Sejong Station, Antarctic Peninsula

Directory of Open Access Journals (Sweden)

J. Kim

2017-11-01

Full Text Available Seasonal variability in the physical characteristics of aerosol particles sampled from the King Sejong Station in the Antarctic Peninsula was investigated over the period between March 2009 and February 2015. Clear seasonal cycles for the total particle concentration (CN were observed. The mean monthly concentration of particles larger than 2.5 nm (CN2.5 was highest during the austral summer, with an average value of 1080.39 ± 595.05 cm−3, and lowest during the austral winter, with a mean value of 197.26 ± 71.71 cm−3. The seasonal patterns in the concentrations of cloud condensation nuclei (CCN and CN coincide, with both concentrations being at a minimum in winter and maximum in summer. The measured CCN spectra were approximated by fitting a power-law function relating the number of CCN for a given supersaturation (SS to each SS value, with fitting coefficients C and kT. The values for C varied from 6.35 to 837.24 cm−3, with a mean of 171.48 ± 62.00 cm−3. The values for kT ranged from 0.07 to 2.19, with a mean of 0.41 ± 0.10. In particular, the kT values during the austral summer were higher than those during the winter, indicating that aerosol particles are more sensitive to SS changes during summer. Furthermore, the annual mean hygroscopicity parameter, κ, was estimated as 0.15 ± 0.05, for a SS of 0.4 %. The effects of the origin and pathway travelled by the air mass on the physical characteristics of the aerosol particles were also determined. The modal diameter of aerosol particles originating in the South Pacific Ocean showed a seasonal variation varying from 0.023 µm in winter to 0.034 µm in summer for the Aitken mode, and from 0.086 µm in winter to 0.109 µm in summer for the accumulation mode.

Experimental Study on Characteristics of Oil Particle Distribution in Water-Gelled Crude Oil Two-Phase Flow System

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Liu Xiaoyan

2014-06-01

Full Text Available The conventional gathering and transportation mode of heating the produced fluid of oil wells with hot water or steam may result in excessive energy consumption. In order to perform the unheated transportation, the idea of hydraulic suspension transport of the gelled crude oil is proposed based on the actual production of Daqing Oilfield, and the experimental system is established to test characteristics of oil particle distribution which have an important effect on the hydraulic suspension transportation. In the experiment, the image of gelled crude oil particle distribution was obtained in a horizontal pipe with inner diameter of 0.053 m, and then the law of particle distribution was investigated by the theoretical model. The results showed that the gelled crude oil hydraulic suspension transport could be achieved without any chemical reagent when the gelled crude oil was transformed into particles and dispersedly suspended in water. The results also showed that the gelled oil particles of 0–4 mm in size accounted for 92% or more of all particles, and the percentage of gelled crude oil particles of a size of 4 mm gradually increased with the increasing mixed flow rate.

Influence of the type of electrolyte on the morphological and crystallographic characteristics of lead powder particles

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Nikolić Nebojša D.

2013-01-01

Full Text Available Lead electrodeposition processes from the basic (nitrate and complex (acetate electrolytes were mutually compared by the scanning electron microscopic and the X-ray diffraction analysis of the produced powder particles. The shape of dendritic particles strongly depended on the type of electrolyte. The dendrites composed of stalk and weakly developed primary branches (the primary type were predominantly formed from the basic electrolyte. The ramified dendrites composed of stalk and of both primary and secondary branches (the secondary type were mainly formed from the complex electrolyte. In the both type of powder particles Pb crystallites were predominantly oriented in the (111 plane. Formation of powder particles of the different shape with the strong (111 preferred orientation was discussed and explained by the consideration of the general characteristics of the growth of a crystal in the electrocrystallization processes. [Projekat Ministarstva nauke Republike Srbije, br. 172046: Electrochemical synthesis and characterization of nanostructured functional materials for application in new technologies

Mechanical particle coating using polymethacrylate nanoparticle agglomerates for the preparation of controlled release fine particles: The relationship between coating performance and the characteristics of various polymethacrylates.

Science.gov (United States)

Kondo, Keita; Kato, Shinsuke; Niwa, Toshiyuki

2017-10-30

We aimed to understand the factors controlling mechanical particle coating using polymethacrylate. The relationship between coating performance and the characteristics of polymethacrylate powders was investigated. First, theophylline crystals were treated using a mechanical powder processor to obtain theophylline spheres (grindability of the agglomerates were attributed to differences in particle structure, resulting from consolidation between colloidal particles. High-grindability agglomerates exhibited higher pulverization as their glass transition temperature (T g ) increased and the further pulverization promoted coating. We therefore conclude that the minimization of polymethacrylate powder by pulverization is an important factor in mechanical particle coating using polymethacrylate with low deformability. Meanwhile, when product temperature during coating approaches T g of polymer, polymethacrylate was soften to show high coating performance by plastic deformation. The effective coating by this mechanism may be accomplished by adjusting the temperature in the processor to the T g . Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of mixing on the rheology and particle characteristics of tungsten-based powder injection molding feedstock

International Nuclear Information System (INIS)

Suri, Pavan; Atre, Sundar V.; German, Randall M.; Souza, Jupiter P. de

2003-01-01

This study investigates the effect of mixing technique and particle characteristics on the rheology and agglomerate dispersion of tungsten-based powder injection molding (PIM) feedstock. Experiments were conducted with as-received (agglomerated) and rod-milled (deagglomerated) tungsten powder mixed in a paraffin wax-polypropylene binder. Increase in the mixing shear rate decreased the agglomerate size of the agglomerated tungsten powder, decreased the viscosity, and improved the flow stability of the feedstock, interpreted as increased homogeneity of the feedstock. Higher solids volume fraction, lower mixing torques, and improved homogeneity were observed with deagglomerated tungsten powder, emphasizing the importance of particle characteristics and mixing procedures in the PIM process. Hydrodynamic stress due to mixing and the cohesive strength of the tungsten agglomerate were calculated to understand the mechanism of deagglomeration and quantify the effect of mixing. It was concluded that deagglomeration occurs due to a combination of rupture and erosion with the local hydrodynamic stresses exceeding the cohesive strength of the agglomerate

Investigation on Mechanical Properties and Reaction Characteristics of Al-PTFE Composites with Different Al Particle Size

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Jia-xiang Wu

2018-01-01

Full Text Available Al-PTFE (aluminum-polytetrafluoroethylene serves as one among the most promising reactive materials (RMs. In this work, six types of Al-PTFE composites with different Al particle sizes (i.e., 50 nm, 1∼2 μm, 6∼7 μm, 12∼14 μm, 22∼24 μm, and 32∼34 μm were prepared, and quasistatic compression and drop weight tests were conducted to characterize the mechanical properties and reaction characteristics of Al-PTFE composites. The reaction phenomenon and stress-strain curves were recorded by a high-speed camera and universal testing machine. The microstructure of selected specimens was anatomized through adopting a scanning electron microscope (SEM to correlate the mesoscale structural characteristics to their macroproperties. As the results indicated, in the case of quasistatic compression, the strength of the composites was decreased (the yield strength falling from 22.7 MPa to 13.6 MPa and the hardening modulus declining from 33.3 MPa to 25 MPa with the increase of the Al particle size. The toughness rose firstly and subsequently decreased and peaked as 116.42 MJ/m3 at 6∼7 μm. The reaction phenomenon occurred only in composites with the Al particle size less than 10 μm. In drop weight tests, six types of specimens were overall reacted. As the Al particle size rose, the ignition energy of the composites enhanced and the composites turned out to be more insensitive to reaction. In a lower strain rate range (10−2·s−1∼102·s−1, Al-PTFE specimens take on different mechanical properties and reaction characteristics in the case of different strain rates. The formation of circumferential open cracks is deemed as a prerequisite for Al-PTFE specimens to go through a reaction.

Determination of in-situ strength on selected bridge element concrete girder and slab of Nagtahan bridge using rebound hammer test

International Nuclear Information System (INIS)

Uy, Bernadette Betsy B.; Banaga, Renato T.

2013-01-01

This study examined the extent of the damage due to fire on the affected areas of the bridge structure. The need to assess the damage of the Nagtahan Bridge is very useful to provide appropriate measures in the repair or in the reinforcement of the bridge, hence will ensure its strength and integrity. The study included two (2) spans of the bridge deck/slab with specific locations of the bridge that were subjected for testing. The Rebound Hammer was used as a preliminary test in evaluating the bridge condition. Its capability is to assess the in-place uniformity of concrete, to delineate regions in a structure of poor quality or deteriorated concrete, and to estimate the in-place strength; and ultimately, for relative comparison between the different structures of the bridge. With the use of the NDT Rebound Hammer Test, the researchers were able to determine whether or not the in-situ strength of the bridge's concrete has been weakened due to fire. The DPW-Standard Specification is the government acceptable manual, containing the acceptance criteria, used as the basis for standard construction procedures in the department.(author)

Seasonal characteristics of water exchange in Beibu Gulf based on a particle tracking model

Science.gov (United States)

Wang, L.; Pan, W.; Yan, X.

2016-12-01

A lagrangian particle tracking model coupled with a three-dimensional Marine Environmental Committee Ocean Model (MEC) is used to study the transport and seasonal characteristics of water exchange in Beibu Gulf. The hydrodynamic model (MEC), which is forced with the daily surface and lateral boundary fluxes, as well as tidal harmonics and monthly climatological river discharges, is applied to simulate the flow field in the gulf during 2014. Using these results, particle tracking method which includes tidal advection and random walk in the horizontal is used to determine the residence times of sub regions within the gulf in response of winter and summer wind forcing. The result shows water exchange processes in the gulf have a similar tendency with seasonal circulation structure. During the sourthwestly prevailing wind in summer, water particles are traped within the gulf that considerably increases the residence time of each sub region. On the contrary, the presence of strong northeastly prevailing wind in winter drives particles to move cyclonicly leading to shorter residence times and rather active water exchanges among sub regions. Similarly, particle tracking is applied to investigate the water transport in Beibu Gulf. As Qiongzhou Strait and the wide opening in the south of the gulf are two significant channels connecting with the open ocean, continuous particle releases are simulated to quantify the influence range and the pathways of these sources water flowing into Beibu Gulf. The results show that water particles originated from Qiongzhou Strait are moving westward due to the year-round strong westward flow transportation. Influencing range in the north of the Beibu Gulf is enlarged by winter northeastly wind, however, it is blocked to the Leizhou Peninsula coastal region by summer westly wind. In the south opening, water particles are transported northward into the gulf along Hainan Island and flushed from Vietnam coastal region to the ocean rapidly by

Postglacial Rebound and Current Ice Loss Estimates from Space Geodesy: The New ICE-6G (VM5a) Global Model

Science.gov (United States)

Peltier, W. R.; Argus, D.; Drummond, R.; Moore, A. W.

2012-12-01

We compare, on a global basis, estimates of site velocity against predictions of the newly constructed postglacial rebound model ICE-6G (VM5a). This model is fit to observations of North American postglacial rebound thereby demonstrating that the ice sheet at last glacial maximum must have been, relative to ICE-5G,thinner in southern Manitoba, thinner near Yellowknife (northwest Territories), thicker in eastern and southern Quebec, and thicker along the British Columbia-Alberta border. The GPS based estimates of site velocity that we employ are more accurate than were previously available because they are based on GPS estimates of position as a function of time determined by incorporating satellite phase center variations [Desai et al. 2011]. These GPS estimates are constraining postglacial rebound in North America and Europe more tightly than ever before. In particular, given the high density of GPS sites in North America, and the fact that the velocity of the mass center (CM) of Earth is also more tightly constrained, the new model much more strongly constrains both the lateral extent of the proglacial forebulge and the rate at which this peripheral bulge (that was emplaced peripheral to the late Pleistocence Laurentia ice sheet) is presently collapsing. This fact proves to be important to the more accurate inference of the current rate of ice loss from both Greenland and Alaska based upon the time dependent gravity observations being provided by the GRACE satellite system. In West Antarctica we have also been able to significantly revise the previously prevalent ICE-5G deglaciation history so as to enable its predictions to be optimally consistent with GPS site velocities determined by connecting campaign WAGN measurements to those provided by observations from the permanent ANET sites. Ellsworth Land (south of the Antarctic peninsula), is observed to be rising at 6 ±3 mm/yr according to our latest analyses; the Ellsworth mountains themselves are observed to be

In-Situ Characteristics of Particle Emissions from Biomass Combustion

International Nuclear Information System (INIS)

Pagels, Joakum; Wierzbicka, Aneta; Bohgard, Mats; Strand, Michael; Lillieblad, Lena; Sanati, Mehri; Swietlicki, Erik

2005-01-01

In this work we used a Scanning Mobility Particle Sizer and an Electrical Low-pressure Impactor to: a) Derive information of the particle morphology through air-borne analysis and b) Identify time and size variations of particle phase components from incomplete combustion and ash-components. The results presented here covers measurements in two moving grate boilers (12 MW operating on moist forest residue and 1.5 MW operating on wood pellets). We have previously shown that PM1 estimated from Electrical Low-Pressure Impactor (ELPI)-measurements consisted of a rather constant background with peaks correlating with CO and OGC peaks. In the 1.5 MW boiler EC contributed to 34% of PM1, while in the 12 MW boiler EC was below 0.5%. Figure 2 shows time variations in the 1.5 MW boiler as the current in three stages of the ELPI-impactor. Note that time-variations increase strongly with particle size. The fraction of the gravimetric mass detected as water-soluble ions (IC) decreased from ∼ 70% for dae= 78 and 133 nm to ∼ 25% for 322 and 510 nm particles and increased to around 50% for particles larger than 1 μm. In the 12 MW boiler time variations were as low as for 128 nm particles and IC recovery was high for all studied particle sizes. Based on these data we conclude that PM consisting of ash-components are formed with small time variations mainly in mobility-sizes below 250 nm, while Elemental Carbon is emitted at high concentrations during peaks on the time-scale 10-30 s, mainly in particle sizes larger than 150 nm. However, the detailed mixing status of these two particle types/materials is still not known

Transient characteristics of thermal energy storage in an enclosure packed with MEPCM particles

International Nuclear Information System (INIS)

Siao, Yong-Hao; Yan, Wei-Mon; Lai, Chi-Ming

2015-01-01

The heat transfer characteristics of phase change materials have been of continuing interest of research due to various potential technical applications, such as the latent-heat thermal energy storage, thermal protection, as well as active/passive electronic cooling. In this work, the transient characteristics of thermal energy storage in a partitioned enclosure filled with microencapsulated phase change material (MEPCM) particles were investigated experimentally and numerically. To examine the different melting temperature effects, two different MEPCM particles are tested. The core phase change materials of the MEPCM are n-octadecane with melting temperature about T M  = 28 °C and 37 °C. The enclosure is partitioned and is differentially heated by the two horizontal isothermal surfaces, while the other vertical surfaces are considered thermally insulated. The studies have been undertaken for five sets of the hot and cold wall temperatures imposed across the enclosure. The consequents show that the numerical results are in agreement with the measured data. At the initial transient, the net energy storage in enclosure, Q net , increases with the time Fo. Finally, the Q net approaches quickly the steady state for the case with a higher temperature difference of T h  − T c . Additionally, higher dimensionless accumulated energy through the hot wall Q h and cold wall Q c is found for a case with higher hot wall temperature T h

The role of the power/efficiency misconception in the rebound effect's size debate: Does efficiency actually lead to a power enhancement?

International Nuclear Information System (INIS)

Ruzzenenti, F.; Basosi, R.

2008-01-01

This paper addresses the question of whether the rebound effect's size is bigger or smaller than one. After a brief review of the related economic literature, a thermodynamic perspective tackles this topic by demonstrating that the dispute over the size of the rebound effect relies on a misconception of the thermodynamic nature of energy efficiency. The dichotomy, in fact, concerns the relationship between efficiency and power output rather than the scale of the economic side effects generated by energy efficiency mutations. Early intuitions of the dichotomy efficiency/power belong to the pioneering works of Stanley Jevons, in the field of economics, and Alfred Lotka in that of biology. Their findings are here approached using the basis of finite-time thermodynamics with a simple amendment, the addition of the time variable to the Carnot machinery. The model shows how a process of power maximization always leads to a sub-optimal efficiency level and additionally, that any efficiency improvement, in the context of low energy costs, will shift the power output of the machine instead of reducing energy consumption. A case study taken from the transport system is presented to elucidate this argument

Rebound effects with long-acting amphetamine or methylphenidate stimulant medication preparations among adolescent male drivers with attention-deficit/hyperactivity disorder.

Science.gov (United States)

Cox, Daniel J; Moore, Melissa; Burket, Roger; Merkel, R Lawrence; Mikami, Amori Yee; Kovatchev, Boris

2008-02-01

This study investigated whether OROS methylphenidate (OROS MPH, Concerta) or extended-release mixed amphetamine salts (se-AMPH ER, Adderall XR) were associated with worsening of driving performance, or drug rebound, relative to placebo 16-17 hours post-ingestion. Nineteen male adolescent drivers aged 17-19 with attention-deficit/hyperactivity disorder (ADHD) were compared on a virtual reality driving simulator and an on-road drive after taking 72 mg of OROS MPH, 30 mg of se-AMPH ER, or placebo. Medication was taken at 08:00 in a randomized, double-blind, placebo-controlled, crossover study. Participants drove a simulator at 17:00, 20:00, 23:00, and 01:00, and drove their own cars over a 16-mile road course at 24:00. The main outcome measures were composite scores of driving performance. Neither OROS MPH nor se-AMPH ER was associated with significant worsening of simulator performance relative to placebo 17 hours post-ingestion in group comparisons. However, inattentive on-road driving errors were significantly more common on se-AMPH ER relative to placebo at midnight (p = 0.04), suggesting possible rebound. During both late simulator and on-road testing, driving performance variance was approximately 300% greater during the se-AMPH ER compared to the OROS MPH condition.

Changes in ground reaction force during a rebound-jump task after hip strength training for single-sided ankle dorsiflexion restriction.

Science.gov (United States)

Kondo, Hitoshi; Someya, Fujiko

2016-01-01

[Purpose] Lateral ankle sprains are common injuries suffered while playing sports, and abnormal forward- and inward-directed ground reaction force occurs during a jumping task. However, the influence of hip muscle strength training on jumping performance after ankle injuries has not been fully examined. This study thus examined changes in ground reaction force during a rebound-jump task after training to strengthen hip muscles. [Subjects and Methods] Ten of 30 female high school basketball players were assigned as subjects who showed a difference of 7 or more degrees in dorsiflexion ranges between the bilateral ankles. The subjects underwent 12 weeks of training to strengthen hip abductors and external rotators. Comparisons between before and after training were made regarding ground reaction force components, hip and knee joint angles, percentage of maximum voluntary contraction in leg muscles, and muscle strength of hip muscles during the rebound-jump task. [Results] After training, the subjects showed increased strength of external rotator muscles, increased percentage of maximum voluntary contraction in the gluteus medius muscle, decreased inward ground reaction force, and increased flexion angles of the hip and knee joints. [Conclusion] This study suggests that training to strengthen hip muscles may ameliorate the inward ground reaction force in athletes with ankle dorsiflexion restriction.

Influence of the shape of soaring particle based on coal-water slurry containing petrochemicals on ignition characteristics

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Valiullin Timur R.

2017-01-01

Full Text Available This paper examines the laws of stable ignition of organic coal-water slurry containing petrochemicals (CWSP. The CWSP is based on the filter cake of coal and scavenge oil. The experiments are performed for individual CWSP particles soaring in a special set-up. The temperature and velocity of an oxidizer flow are varied between 500-1200 K, and 0.5-3 m/s. The dimensions (longitudinal and transverse of particles range are from 0.5 mm to 5 mm. The study indicates how the shape of a fuel particle (sphere, ellipsoid, and polyhedron influences its ignition characteristics (delay time, minimum temperature, modes, stages. Based on the experimental results, the paper explains why the surface configuration of particles influences the conditions of heat transfer with an oxidizer. The results obtained for soaring particles are compared with the results for fixed CWSP particles having different surface configurations (sphere, ellipsoid, and polyhedron. In general, the study may contribute to the expansion of the fuel resource base. The experimental data may be used for the development of the technologies of burning CWSP prepared by recycling traditional fuels. As a result of this study, several recommendations for the practical application of research results are made.

Accuracy of the new ICare rebound tonometer vs. other portable tonometers in healthy eyes.

Science.gov (United States)

García-Resúa, Carlos; González-Meijome, José M; Gilino, Jorge; Yebra-Pimentel, Eva

2006-02-01

The ICare (Tiolat Oy, Helsinki, Finland) is a new portable tonometer that measures intraocular pressure (IOP) with a new rebound method, in which a very light probe is used to make momentary contact with the cornea in slow motion. The purpose of this study is to assess the accuracy of the ICare IOP measurements by comparing them against other portable tonometers: Perkins applanation tonometer and Tono-Pen XL digital tonometer (Medtronic Solan, Jacksonville, FL). Sixty-five young subjects were assessed with each of the tonometers. ICare tonometry was performed first, followed by Perkins applanation tonometry and Tono-Pen XL in a random order. Regression analysis was used to evaluate the relationship between the Perkins tonometer and the remaining tonometers used in this study. Tonometers were also compared by plotting the difference between the methods against the mean. The hypothesis of zero bias was examined by a paired t test and the 95% limits of agreement (LoA) were calculated. ICare and Tono-Pen XL significantly overestimate IOP when compared with Perkins applanation tonometry. The mean of the difference between Perkins and ICare and Perkins and Tono-Pen XL was (mean +/- standard deviation) -3.35 +/- 2.28 mm Hg and -2.78 +/- 2.53 mm Hg, respectively. The 95% LoA between Perkins tonometry and ICare tonometry were between -7.81 and +1.12 and between Perkins tonometry and Tono-Pen XL tonometry between -7.74 and +2.18. Compared with Perkins tonometry, the ICare tonometer allows clinicians to estimate IOP with a portable, rapid, and noninvasive method with similar reliability to that offered by Tono-Pen XL. Clinicians should be aware of the systematic overestimation of IOP with the ICare. Further research is needed to evaluate the performance of rebound tonometry in populations with higher IOP and assess the reliability of this technique in the early detection and follow up of glaucomatous patients.

Effect of non-Newtonian characteristics of blood on magnetic particle capture in occluded blood vessel

Science.gov (United States)

Bose, Sayan; Banerjee, Moloy

2015-01-01

Magnetic nanoparticles drug carriers continue to attract considerable interest for drug targeting in the treatment of cancer and other pathological conditions. Magnetic carrier particles with surface-bound drug molecules are injected into the vascular system upstream from the desired target site, and are captured at the target site via a local applied magnetic field. Herein, a numerical investigation of steady magnetic drug targeting (MDT) using functionalized magnetic micro-spheres in partly occluded blood vessel having a 90° bent is presented considering the effects of non-Newtonian characteristics of blood. An Eulerian-Lagrangian technique is adopted to resolve the hemodynamic flow and the motion of the magnetic particles in the flow using ANSYS FLUENT. An implantable infinitely long cylindrical current carrying conductor is used to create the requisite magnetic field. Targeted transport of the magnetic particles in a partly occluded vessel differs distinctly from the same in a regular unblocked vessel. Parametric investigation is conducted and the influence of the insert configuration and its position from the central plane of the artery (zoffset), particle size (dp) and its magnetic property (χ) and the magnitude of current (I) on the "capture efficiency" (CE) is reported. Analysis shows that there exists an optimum regime of operating parameters for which deposition of the drug carrying magnetic particles in a target zone on the partly occluded vessel wall can be maximized. The results provide useful design bases for in vitro set up for the investigation of MDT in stenosed blood vessels.

Radiological dispersal device outdoor simulation test: Cesium chloride particle characteristics

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Don, E-mail: lee.sangdon@epa.gov [U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Snyder, Emily G.; Willis, Robert [U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Fischer, Robert; Gates-Anderson, Dianne; Sutton, Mark [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Viani, Brian [Simbol Mining Corp., Pleasanton, CA 94566 (United States); Drake, John [U.S. Environmental Protection Agency, Cincinnati, OH 45268 (United States); MacKinney, John [U.S. Department of Homeland Security, Washington, DC 20528 (United States)

2010-04-15

Particles were generated from the detonation of simulated radiological dispersal devices (RDDs) using non-radioactive CsCl powder and explosive C4. The physical and chemical properties of the resulting particles were characterized. Two RDD simulation tests were conducted at Lawrence Livermore National Laboratory: one of the simulated RDDs was positioned 1 m above a steel plate and the other was partially buried in soil. Particles were collected with filters at a distance of 150 m from the origin of the RDD device, and particle mass concentrations were monitored to identify the particle plume intensity using real time particle samplers. Particles collected on filters were analyzed via computer-controlled scanning electron microscopy coupled with energy dispersive X-ray spectrometry (CCSEM/EDX) to determine their size distribution, morphology, and chemical constituents. This analysis showed that particles generated by the detonation of explosives can be associated with other materials (e.g., soil) that are in close proximity to the RDD device and that the morphology and chemical makeup of the particles change depending on the interactions of the RDD device with the surrounding materials.

Radiological dispersal device outdoor simulation test: Cesium chloride particle characteristics

International Nuclear Information System (INIS)

Lee, Sang Don; Snyder, Emily G.; Willis, Robert; Fischer, Robert; Gates-Anderson, Dianne; Sutton, Mark; Viani, Brian; Drake, John; MacKinney, John

2010-01-01

Particles were generated from the detonation of simulated radiological dispersal devices (RDDs) using non-radioactive CsCl powder and explosive C4. The physical and chemical properties of the resulting particles were characterized. Two RDD simulation tests were conducted at Lawrence Livermore National Laboratory: one of the simulated RDDs was positioned 1 m above a steel plate and the other was partially buried in soil. Particles were collected with filters at a distance of 150 m from the origin of the RDD device, and particle mass concentrations were monitored to identify the particle plume intensity using real time particle samplers. Particles collected on filters were analyzed via computer-controlled scanning electron microscopy coupled with energy dispersive X-ray spectrometry (CCSEM/EDX) to determine their size distribution, morphology, and chemical constituents. This analysis showed that particles generated by the detonation of explosives can be associated with other materials (e.g., soil) that are in close proximity to the RDD device and that the morphology and chemical makeup of the particles change depending on the interactions of the RDD device with the surrounding materials.

Evaluation of rebound tonometry in non-human primates.

Science.gov (United States)

Elsmo, Elizabeth J; Kiland, Julie A; Kaufman, Paul L; McLellan, Gillian J

2011-04-01

To determine the accuracy and reproducibility of intraocular pressure (IOP) measurements obtained with the TonoVet® rebound tonometer in cynomolgus macaques and to determine the effects of corneal thickness on measurements obtained by the TonoVet®. The anterior chambers of both eyes of anesthetized monkeys were cannulated with branched 23-G needles; one branch was connected to a vertically adjustable reservoir and the other to a pressure transducer. IOP was increased by 5 mmHg increments and then decreased by 10 mmHg decrements. IOP was measured using the TonoVet® at each increment and decrement by 2 independent observers and at every other increment and every decrement by a single observer using 'minified' Goldmann applanation tonometry. Central corneal thickness was measured with a PachPen(TM) ultrasonic pachymeter. TonoVet® readings correlated well with manometric IOP (slope = 0.972, r(2) coefficient = 0.955). No significant differences were observed when comparing eyes or operators; however there was a non-significant trend for TonoVet® readings taken in right eyes to be closer to manometric IOP than those taken in left eyes. The TonoVet® had a non-significant tendency to underestimate manometric IOP. TonoVet® readings obtained during the decremental phase of the experiment were significantly closer (p tonometer is a reliable and accurate tool for the measurement of IOP in cynomolgus macaques. This tonometer has several advantages, including portability, ease of use, and brief contact with the corneal surface making topical anesthetics unnecessary. Copyright © 2011 Elsevier Ltd. All rights reserved.

High-LET dose-response characteristics by track structure theory of heavy charged particles

International Nuclear Information System (INIS)

Hansen, J.W.; Olsen, K.J.

1981-09-01

The track structure theory developed by Katz and co-workers ascribes the effect of high-LET radiation to the highly inhomogeneous dose distribution due to low energy Δ-rays ejected from the particle track. The theory predicts the effectiveness of high-LET radiation by using the ion parameters zsub(eff') effective charge of the ion, and β = v/c, the relative ion velocity, together with the characteristic dose D 37 derived from low-LET dose-response characteristic of the detector and the approximate size asub(0) of the sensitive element of the detector. 60 Co gamma-irradiation is used as a reference low-LET radiation, while high-LET radiation ranging from 16 MeV protons to 4 MeV/amu 16 0-ions covering an initial LET range of 30-5500 MeVcm 2 /g is obtained from a tandem Van de Graaff accelerator. A thin film (5mg/cm 2 ) radiochromic dye cyanide plastic dosemeter was used as detector with the characteristic dose of 16.8 Mrad and a sensitive element size of 10 -7 cm. Theoretical and experimental effectiveness, RBE, agreed within 10 to 25% depending on LET. (author)

Inclusive characteristics of the nuclear target fragmentation products induced by relativistic particles

International Nuclear Information System (INIS)

Bogatin, V.I.; Ganza, E.A.; Lozhkin, O.V.; Murin, Yu.A.; Oplavin, V.S.; Perfilov, N.A.; Yakovlev, Yu.P.

1981-01-01

An experimental investigation of inclusive characteristics of nuclei-target fragmentation is conducted for further development and test of physical value of the earlier suggested nuclear fragmentation model based on the connection of the fragmentation with fluctuations of the quasiparticle density in the two-component quantum liquid, an experimental investigation of the inclusive characteristics of the nuclei-target fragmentation is carried out. The processes of sup(3, 4, 6, 8)He and sup(6, 7, 8, 9, 11)Li fragment formation during the interaction of relativistic protons (Esub(p)=6.7 GeV) and deutrons (Esub(d)=3.1 GeV) with 112 Sn and 124 Sn isotopes are studied by the method of semiconductive ΔE-E detectors. Differential energy spectra of fragments and isotopic ratio of cross sections of their formation as well as data on the dependence of isotopic ratios of fragmentation cross sections on the energy of incident particles and on the fragment energy are obtained. Presented is a phenomenological model of fragmentation within the frames of which the obtained experimental data are analyzed [ru

Rebound macular edema following oral acetazolamide therapy for juvenile X-linked retinoschisis in an Italian family

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Galantuomo MS

2016-11-01

this abnormality. Of note, after acetazolamide interruption, a rebound effect on cystoid macular edema reduced the beneficial effects of the initial therapy for RS1 from p.Arg197Cys mutation. Indeed, a minimal rebound effect on cystoid macular edema, and an improvement in visual acuity, was observed in patient 1 during the six months of treatment. Conversely, in patient 2, an initial improvement in cystoid macular edema was not associated with visual acuity changes, followed by a marked rebound effect. Conclusion: This study showed that the sequential use of acetazolamide tablets and dorzolamide eye drops should be considered and studied further as a possible treatment for macular edema and visual impairment in patients with RS1 from a hemizygous p.Arg197Cys mutation. Keywords: juvenile X-linked retinoschisis, oral acetazolamide, topical dorzolamide, cystoid macular edema, macular schisis, foveal zone thickness

Gas hydrate dissociation off Svalbard induced by isostatic rebound rather than global warming.

Science.gov (United States)

Wallmann, Klaus; Riedel, M; Hong, W L; Patton, H; Hubbard, A; Pape, T; Hsu, C W; Schmidt, C; Johnson, J E; Torres, M E; Andreassen, K; Berndt, C; Bohrmann, G

2018-01-08

Methane seepage from the upper continental slopes of Western Svalbard has previously been attributed to gas hydrate dissociation induced by anthropogenic warming of ambient bottom waters. Here we show that sediment cores drilled off Prins Karls Foreland contain freshwater from dissociating hydrates. However, our modeling indicates that the observed pore water freshening began around 8 ka BP when the rate of isostatic uplift outpaced eustatic sea-level rise. The resultant local shallowing and lowering of hydrostatic pressure forced gas hydrate dissociation and dissolved chloride depletions consistent with our geochemical analysis. Hence, we propose that hydrate dissociation was triggered by postglacial isostatic rebound rather than anthropogenic warming. Furthermore, we show that methane fluxes from dissociating hydrates were considerably smaller than present methane seepage rates implying that gas hydrates were not a major source of methane to the oceans, but rather acted as a dynamic seal, regulating methane release from deep geological reservoirs.

Agreement among Goldmann applanation tonometer, iCare, and Icare PRO rebound tonometers; non-contact tonometer; and Tonopen XL in healthy elderly subjects.

Science.gov (United States)

Kato, Yoshitake; Nakakura, Shunsuke; Matsuo, Naoko; Yoshitomi, Kayo; Handa, Marina; Tabuchi, Hitoshi; Kiuchi, Yoshiaki

2018-04-01

To evaluate the inter-device agreement among the Goldmann applanation tonometer (GAT), iCare and Icare PRO rebound tonometers, non-contact tonometer (NCT), and Tonopen XL tonometer. Sixty healthy elderly subjects were enrolled. The intraocular pressure (IOP) in each subject's right eye was measured thrice using each of the five tonometers. Intra-device agreement was evaluated by calculating intraclass correlation coefficients (ICCs). Inter-device agreement was evaluated by ICC and Bland-Altman analyses. ICCs for intra-device agreement for each tonometer were >0.8. IOP as measured by iCare (mean ± SD, 11.6 ± 2.5 mmHg) was significantly lower (p tonometers (all ICCs tonometers ranged from 14.94 to 16.47 mmHg. Among the other tonometers, however, the widths of 95% limits of agreement ranged from 7.91 to 9.24 mmHg. There was good inter-device agreement among GAT, rebound tonometers, and NCT. Tonopen XL shows the worst agreement with the other tonometers; therefore, we should pay attention to its' respective IOP. Japan Clinical Trials Register; number: UMIN000011544.

Impact of meteorological conditions on airborne fine particle composition and secondary pollutant characteristics in urban area during winter-time

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Klaus Schäfer

2016-06-01

Full Text Available The assessment of airborne fine particle composition and secondary pollutant characteristics in the case of Augsburg, Germany, during winter (31 January–12 March 2010 is studied on the basis of aerosol mass spectrometry (3 non-refractory components and organic matter, 3 positive matrix factorizations (PMF factors, particle size distributions (PSD, 5 size modes, 5 PMF factors, further air pollutant mass concentrations (7 gases and VOC, black carbon, PM10, PM2.5 and meteorological measurements, including mixing layer height (MLH, with one-hourly temporal resolution. Data were subjectively assigned to 10 temporal phases which are characterised by different meteorological influences and air pollutant concentrations. In each phase hierarchical clustering analysis with the Ward method was applied to the correlations of air pollutants, PM components, PM source contributions and PSD modes and correlations of these data with all meteorological parameters. This analysis resulted in different degrees of sensitivities of these air pollutant data to single meteorological parameters. It is generally found that wind speed (negatively, MLH (negatively, relative humidity (positively and wind direction influence primary pollutant and accumulation mode particle (size range 100–500 nm concentrations. Temperature (negatively, absolute humidity (negatively and also relative humidity (positively are relevant for secondary compounds of PM and particle (PM2.5, PM10 mass concentrations. NO, nucleation and Aitken mode particle and the fresh traffic aerosol concentrations are only weakly dependent on meteorological parameters and thus are driven by emissions. These daily variation data analyses provide new, detailed meteorological influences on air pollutant data with the focus on fine particle composition and secondary pollutant characteristics and can explain major parts of certain PM component and gaseous pollutant exposure.

Effect of Pressurized Metered Dose Inhaler Spray Characteristics and Particle Size Distribution on Drug Delivery Efficiency.

Science.gov (United States)

Yousefi, Morteza; Inthavong, Kiao; Tu, Jiyuan

2017-10-01

A key issue in pulmonary drug delivery is improvement of the delivery device for effective and targeted treatment. Pressurized metered dose inhalers (pMDIs) are the most popular aerosol therapy device for treating lung diseases. This article studies the effect of spray characteristics: injection velocity, spray cone angle, particle size distribution (PSD), and its mass median aerodynamic diameter (MMAD) on drug delivery. An idealized oral airway geometry, extending from mouth to the main bronchus, was connected to a pMDI device. Inhalation flow rates of 15, 30, and 60 L/min were used and drug particle tracking was a one-way coupled Lagrangian model. The results showed that most particles deposited in the pharynx, where the airway has a reduced cross-sectional area. Particle deposition generally decreased with initial spray velocity and with increased spray cone angle for 30 and 60 L/min flow rates. However, for 15 L/min flow rate, the deposition increased slightly with an increase in the spray velocity and cone angle. The effect of spray cone angle was more significant than the initial spray velocity on particle deposition. When the MMAD of a PSD was reduced, the deposition efficiency also reduces, suggesting greater rates of particle entry into the lung. The deposition rate showed negligible change when the MMAD was more than 8 μm. Spray injection angle and velocity change the drug delivery efficacy; however, the efficiency shows more sensitivity to the injection angle. The 30 L/min airflow rate delivers spray particles to the lung more efficiently than 15 and 60 L/min airflow rate, and reducing MMAD can help increase drug delivery to the lung.

Effects of cocaine, methamphetamine and modafinil challenge on sleep rebound after paradoxical sleep deprivation in rats

Directory of Open Access Journals (Sweden)

R.C.S Martins

2008-01-01

Full Text Available Sleep loss is both common and critically relevant to our society and might lead to the abuse of psychostimulants such as amphetamines, cocaine and modafinil. Since psychoactive substance abuse often occurs within a scenario of sleep deficit, the purpose of this investigation was to compare the sleep patterns of rats challenged with cocaine (7 mg/kg, ip, methamphetamine (7 mg/kg, ip, or modafinil (100 mg/kg, ip subsequent to paradoxical sleep deprivation (PSD for 96 h. Our results show that, immediately after 96 h of PSD, rats (10 per group that were injected with a psychostimulant presented lower percentages of paradoxical sleep compared to those injected with saline (P < 0.01. Regarding slow wave sleep (SWS, rats injected with psychostimulants after PSD presented a late rebound (on the second night subsequent to the injection in the percentage of this phase of sleep when compared to PSD rats injected with saline (P < 0.05. In addition, the current study has produced evidence of the characteristic effect of each drug on sleep architecture. Home cage control rats injected with modafinil and methamphetamine showed a reduction in SWS compared with the saline group. Methamphetamine affected sleep patterns most, since it significantly reduced paradoxical sleep, SWS and sleep efficiency before and after PSD compared to control (P < 0.05. Cocaine was the psychostimulant causing the least changes in sleep pattern in relation to those observed after saline injection. Therefore, our results suggest that abuse of these psychostimulants in a PSD paradigm aggravates their impact on sleep patterns.

Rebound Effect or Induced Demand? Analyzing the Compound Dual Effects on VMT in the U.S.

Directory of Open Access Journals (Sweden)

Jihye Byun

2017-02-01

Full Text Available This research explored the dual influence of fuel efficiency and roadway capacity on vehicle distance traveled. The empirical study was conducted by applying a generalized least square (GLS analysis to the U.S. state-level panel data of fuel efficiency, roadway lane-miles, and vehicle miles traveled (VMT for over three decades (1980–2010. The analysis confirmed the co-existence of rebound effect and induced demand on driving distances over the decades—improved fuel efficiency and expanded roadway capacity caused additional vehicle distance traveled, partially offsetting the benefits of the measures taken. Furthermore, the results showed that the magnitude of each effect would be unjustifiably overestimated if this dual influence was not taken into consideration.

Effects of Injection Timing on Fluid Flow Characteristics of Partially Premixed Combustion Based on High-Speed Particle Image Velocimetry

KAUST Repository

Izadi Najafabadi, Mohammad; Tanov, Slavey; Wang, Hua; Somers, Bart; Johansson, Bengt; Dam, Nico

2017-01-01

behavior. The scope of the present study is to investigate the fluid flow characteristics of PPC at different injection timings. To this end, high-speed Particle Image Velocimetry (PIV) is implemented in a light-duty optical engine to measure fluid flow

Characteristics of flux variations of energetic particles associated with storm sudden commencement at synchronous orbit

International Nuclear Information System (INIS)

Tomomura, Kiyoshi; Kato, Yoshio; Sakurai, Tohru

1982-01-01

Characteristics of flux variations of energetic particles associated with Storm Sudden Commencement (SSC) are examined on the basis of the particle's data observed by solid state detecter onboard the synchronous satellite, GMS ''Himawari'', during the period from Febuary 1978 to August 1979. The energy of the particles are covered from 1.2 to 4.0 MeV for proton and greater than 2 MeV for electron, respectively. The flux variations for protons generally increase in association with SSC. However, for electrons, they show the increase except 7 events (the decrease event) among 40 events studied. It is evident that the values of the flux attained immediately after SSC (J) clearly depend on those just before SSC(J 0 ). They follow a Power law (J proportional J 0 sup( n)). The variation of the proton flux ( + ΔJ + = + J - J 0+ ) increases with the value of the flux just before SSC. In both increase and decrease events for electrons, the variation of the flux tends to increase until the flux just before SSC attains the value of 10 4 , then to decrease as its value exceeds 10 4 . (author)

Universal shape characteristics for the mesoscopic star-shaped polymer via dissipative particle dynamics simulations

Science.gov (United States)

Kalyuzhnyi, O.; Ilnytskyi, J. M.; Holovatch, Yu; von Ferber, C.

2018-05-01

In this paper we study the shape characteristics of star-like polymers in various solvent quality using a mesoscopic level of modeling. The dissipative particle dynamics simulations are performed for the homogeneous and four different heterogeneous star polymers with the same molecular weight. We analyse the gyration radius and asphericity at the poor, good and θ-solvent regimes. Detailed explanation based on interplay between enthalpic and entropic contributions to the free energy and analyses on of the asphericity of individual branches are provided to explain the increase of the apsphericity in θ-solvent regime.

Characteristics of the groups of charged particles in bar pp,pp and K-p interactions at 32 GeV/c

International Nuclear Information System (INIS)

Bogolubsky, M.Yu.; Levitsky, M.S.; Maksimov, V.V.

1995-01-01

In the clan model, a method is developed for determining the following characteristics of the groups of charged particles: group multiplicity in an interval, particle multiplicity in a group, and width distribution of groups. Distribution densities are obtained for particles originating from clans produced at a given rapidity point with given width in bar pp, K - p, and pp interactions at 32 GeV/c. It is shown that the differences in the rate of growth of factorial moments in bar pp and K - p interactions are due to a difference in the relative contributions of small-width clans. 12 refs., 13 figs., 2 tabs

Experimental Study on Effects of Particle Shape and Operating Conditions on Combustion Characteristics of Single Biomass Particles

DEFF Research Database (Denmark)

Momeni, M.; Yin, Chungen; Kær, Søren Knudsen

2013-01-01

An experimental study is performed to investigate the ignition, devolatilization, and burnout of single biomass particles of various shapes and sizes under process conditions that are similar to those in an industrial combustor. A chargecoupled device (CCD) camera is used to record the whole...... combustion process. For the particles with similar volume (mass), cylindrical particles are found to lose mass faster than spherical particles and the burnout time is shortened by increasing the particle aspect ratio (surface area). The conversion times of cylindrical particles with almost the same surface...... area/volume ratio are very close to each other. The ignition, devolatilization, and burnout times of cylindrical particles are also affected by the oxidizer temperature and oxygen concentration, in which the oxygen concentration is found to have a more pronounced effect on the conversion times at lower...

Colloids exposed to random potential energy landscapes: From particle number density to particle-potential and particle-particle interactions

International Nuclear Information System (INIS)

Bewerunge, Jörg; Capellmann, Ronja F.; Platten, Florian; Egelhaaf, Stefan U.; Sengupta, Ankush; Sengupta, Surajit

2016-01-01

Colloidal particles were exposed to a random potential energy landscape that has been created optically via a speckle pattern. The mean particle density as well as the potential roughness, i.e., the disorder strength, were varied. The local probability density of the particles as well as its main characteristics were determined. For the first time, the disorder-averaged pair density correlation function g (1) (r) and an analogue of the Edwards-Anderson order parameter g (2) (r), which quantifies the correlation of the mean local density among disorder realisations, were measured experimentally and shown to be consistent with replica liquid state theory results.

The role of the power/efficiency misconception in the rebound effect's size debate: Does efficiency actually lead to a power enhancement?

Energy Technology Data Exchange (ETDEWEB)

Ruzzenenti, F. [Center for Complex System Investigations, University of Siena (Italy); Basosi, R. [Center for Complex System Investigations, University of Siena (Italy); Department of Chemistry, University of Siena (Italy)

2008-09-15

This paper addresses the question of whether the rebound effect's size is bigger or smaller than one. After a brief review of the related economic literature, a thermodynamic perspective tackles this topic by demonstrating that the dispute over the size of the rebound effect relies on a misconception of the thermodynamic nature of energy efficiency. The dichotomy, in fact, concerns the relationship between efficiency and power output rather than the scale of the economic side effects generated by energy efficiency mutations. Early intuitions of the dichotomy efficiency/power belong to the pioneering works of Stanley Jevons, in the field of economics, and Alfred Lotka in that of biology. Their findings are here approached using the basis of finite-time thermodynamics with a simple amendment, the addition of the time variable to the Carnot machinery. The model shows how a process of power maximization always leads to a sub-optimal efficiency level and additionally, that any efficiency improvement, in the context of low energy costs, will shift the power output of the machine instead of reducing energy consumption. A case study taken from the transport system is presented to elucidate this argument. (author)

Four-dimensional jets of hadrons: universal characteristics of multiple production of particles

International Nuclear Information System (INIS)

Baldin, A.M.; Batyunya, B.V.; Gramenitskii, I.M.; Grishin, V.G.; Didenko, L.A.; Kuznetsov, A.A.; Metreveli, Z.V.

1986-01-01

In a new relativistically invariant approach, data on multiple production of particles are analyzed in pp, p-barp, π - p, π - C, pC, and pTa interactions in the momentum range from 6 to 205 GeV/c. Distributions of hadrons (π - , K 0 /sub S/, Λ) in the square of the 4-velocity (b/sub k/) relative to the jet axis are obtained. It is shown that at a momentum p/sub lab/ ≥22 GeV/c these distributions do not depend on energy and are identical for hadronization of quarks and of multiquark systems. The observed universal properties of 4-dimensional jets of hadrons apparently are fundamental characteristics of interactions of color charges with the vacuum

The transmission characteristics of indoor particles under different ventilation conditions

Directory of Open Access Journals (Sweden)

Lv Yang

2017-01-01

Full Text Available In modern society, ventilation is an important method for removing indoor particles. This study applies the parameter of attenuation index to analyze the effect of the removal of indoor particles in the two typical ventilation strategies called ceiling exhaust and slit exhaust strategy. Experiment was conducted in a chamber and riboflavin particles were used as the indoor particles source, instantaneous microbial detection (IMD used to measure the particulate concentration. Conclusions can be found that air exchange rate is an important factor affecting the indoor particle concentration distribution. In the process of indoor free settling(air exchange rate is 0 h-1, the deposition rate were 0.086 h-1, 0.122 h-1, 0.173 h-1 for the particles of 0.5–1.0 μm, 1.0–3.0μm and 3.0–5.0 μm. When the air exchange rate increased to 2.5 h-1, the differences in the attenuation index is significant. There was also a significant linear relationship between air exchange rate and attenuation index. Furthermore, the effect of the slit exhaust strategy on the removal of coarse particles is more remarkable as the increasing air exchange rate.

Adsorption-desorption characteristics of plutonium and americium with sediment particles in the estuarine environment: studies using plutonium-237 and americium-241

International Nuclear Information System (INIS)

Murray, C.N.; Fukai, R.

1975-01-01

The particle formation of plutonium and americium, their adsorption onto fresh water sediments and the desorption from the sediments in sea water were studied in the Laboratory under simulated river-estuary conditions, using γ-emitting plutonium-237 and americium-241. The results of the experiments show that the particle formation of plutonium depends on its valence states, on pH and on the salinity of the medium. For river water at pH4, some 25%, 20% and 30% of the added 237 Pu was in particulate form, larger than 0.45 μm, for Pu (III), Pu (IV) and Pu (VI), respectively, while 65%, 90% and 50% of the respective valence states was associated with particles at pH 8. In sea water the general pattern remains similar, although Pu (VI) is more soluble in sea water owing to higher ligand concentrations for carbonate and bicarbonate complexes. The pH-dependency of particle formation of Am (III) is more steep than that of plutonium and seems to be influenced by colloidal substances occurring in the experimental media. The adsorption-desorption characteristics of plutonium and americium with the sediment in river water as well as sea water reflect the characteristics of their particle formation, being dependent upon such properties as valence states, the pH and salinity of the medium. A sewage effluent added to the media has small but measurable effects on the adsorption-desorption processes of plutonium. (author)

Investigating the settling dynamics of cohesive silt particles with particle-resolving simulations

Science.gov (United States)

Sun, Rui; Xiao, Heng; Sun, Honglei

2018-01-01

The settling of cohesive sediment is ubiquitous in aquatic environments, and the study of the settling process is important for both engineering and environmental reasons. In the settling process, the silt particles show behaviors that are different from non-cohesive particles due to the influence of inter-particle cohesive force. For instance, the flocs formed in the settling process of cohesive silt can loosen the packing, and thus the structural densities of cohesive silt beds are much smaller than that of non-cohesive sand beds. While there is a consensus that cohesive behaviors depend on the characteristics of sediment particles (e.g., Bond number, particle size distribution), little is known about the exact influence of these characteristics on the cohesive behaviors. In addition, since the cohesive behaviors of the silt are caused by the inter-particle cohesive forces, the motions of and the contacts among silt particles should be resolved to study these cohesive behaviors in the settling process. However, studies of the cohesive behaviors of silt particles in the settling process based on particle-resolving approach are still lacking. In the present work, three-dimensional settling process is investigated numerically by using CFD-DEM (Computational Fluid Dynamics-Discrete Element Method). The inter-particle collision force, the van der Waals force, and the fluid-particle interaction forces are considered. The numerical model is used to simulate the hindered settling process of silt based on the experimental setup in the literature. The results obtained in the simulations, including the structural densities of the beds, the characteristic lines, and the particle terminal velocity, are in good agreement with the experimental observations in the literature. To the authors' knowledge, this is the first time that the influences of non-dimensional Bond number and particle polydispersity on the structural densities of silt beds have been investigated separately

Frequent hepatitis B virus rebound among HIV-hepatitis B virus-coinfected patients following antiretroviral therapy interruption

DEFF Research Database (Denmark)

Dore, Gregory J; Soriano, Vicente; Rockstroh, Jürgen

2010-01-01

.0002), nondetectable HBV DNA at baseline (P = 0.007), and black race (P = 0.03). Time to ART reinitiation was shorter (7.5, 15.6, and 17.8 months; P hepatitis C virus-positive and non-HBV/hepatitis...... C virus participants in the drug conservation arm. No hepatic decompensation events occurred among HBV-positive participants in either arm. CONCLUSION: HBV DNA rebound following ART interruption is common and may be associated with accelerated immune deficiency in HIV-HBV-coinfected patients.......BACKGROUND: The impact of antiretroviral therapy (ART) interruption in HIV-hepatitis B virus (HBV)-coinfected patients was examined in the Strategic Management of AntiRetroviral Therapy (SMART) study. METHODS: Plasma HBV DNA was measured in all hepatitis B surface antigen-positive (HBV...

Prediction of the Soil Water Characteristic from Soil Particle Volume Fractions

DEFF Research Database (Denmark)

Naveed, Muhammad; Møldrup, Per; Tuller, Markus

2012-01-01

Modelling water distribution and flow in partially saturated soils requires knowledge of the soil-water characteristic (SWC). However, measurement of the SWC is challenging and time-consuming, and in some cases not feasible. This study introduces two predictive models (Xw-model and Xw......*-model) for the SWC, derived from readily available soil properties such as texture and bulk density. A total of 46 soils from different horizons at 15 locations across Denmark were used for models evaluation. The Xw-model predicts the volumetric water content as a function of volumetric fines content (organic matter...... (organic matter, clay, silt, fine and coarse sand), variably included in the model depending on the pF value. The volumetric content of a particular soil particle size fraction was included in the model if it was assumed to contribute to the pore size fraction still occupied with water at the given p...

Particle therapy

Energy Technology Data Exchange (ETDEWEB)

Raju, M.R.

1993-09-01

Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.

Particle therapy

International Nuclear Information System (INIS)

Raju, M.R.

1993-01-01

Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics

Diagnostic accuracy of the iCare rebound tonometer compared to the Perkins applanation tonometer in assessing intraocular pressure in rural patients.

Science.gov (United States)

Li, Yifan; Carpenter, Christopher R; Nicholson, Kathryn; Milne, William Ken

2015-12-01

Vision health is recognized as a critical unmet need in North America. The ocular morbidity associated with glaucoma results from increased intraocular pressure (IOP) and early detection is crucial for the management of glaucoma. Our objective was to find a diagnostically accurate screening tool for intraocular hypertension that can be used in rural communities. We sought to validate the diagnostic accuracy of the iCare rebound tonometer against the gold standard Perkins applanation tonometer (PAT) in measuring IOP. Patients from two rural communities in Ontario, Canada visiting their optometrists for routine appointments had their IOP measured by a non-contact tonometer (NCT), an iCare rebound tonometer, and a Perkins applanation tonometer (PAT). Values of sensitivity, specificity, and likelihood ratios for a positive and negative result were calculated for the iCare and the NCT. Complete data was collected from 209 patients. Overall, the iCare tonometer had high levels of validity, as compared to the gold standard PAT. The iCare tonometer displayed excellent sensitivity of 98.3% (90-99%, 95% CI) and excellent negative likelihood ratio of 0.024 (0.0088-0.066, 95% CI) which is useful for ruling out intraocular hypertension. The iCare tonometer is a reasonably valid tool for detecting elevated IOP. Its ease of use, simplicity, and accessibility makes it a good screening tool to improve eye health in rural areas.

Effect of Rebound Exercises and Circuit Training on Complications Associated with Type 2 Diabetes: Protocol for a Randomized Controlled Trial.

Science.gov (United States)

Kaka, Bashir; Maharaj, Sonill Sooknunan

2018-05-07

The incidence of type 2 diabetes mellitus, a chronic lifestyle disease, and its complications are on the rise. Exercise has been documented as being effective in the management of musculoskeletal pain, depression, and reduction of hyperglycemia in diabetic patients. However, there is no consensus regarding the types of exercise that reduce musculoskeletal pain and depression and improve quality of life as well as respiratory function among individuals with type 2 diabetes. The objective of this study is to determine the effects of rebound and circuit training on musculoskeletal pain, blood glucose level, cholesterol level, quality of life, depression, and respiratory parameters in patients with type 2 diabetes mellitus. A total of 70 participants are expected to be recruited in this single blind randomized controlled trial. Computer-generated random numbers will be used to randomize the participants into 3 groups, namely, the rebound exercise group, the circuit exercise group, and the control group. Measurements will be taken at baseline and at the end of the 8 weeks of the study. Participants' musculoskeletal pain will be assessed using the visual analog scale, quality of life will be assessed using the SF 12 Health Survey Questionnaire, depression using the Beck Depression Inventory, respiratory parameters using the spirometer, and biochemical parameters such as glucose level and cholesterol level using the glucometer. Data will be analyzed using descriptive statistics and inferential statistics of multivariate analysis of variance between the groups and paired t test within the group. Alpha will be set at .05. The results of this study will identify the effectiveness of rebound exercise and circuit training, compared with the control, in the management of type 2 diabetes mellitus and on quality of life, musculoskeletal pain, depression, glycemic control, cholesterol level, as well as improvement in respiratory function. Though different additional strategies

Recycling and particle confinement characteristics in TFR 600

International Nuclear Information System (INIS)

1980-07-01

Recycling rates and gross particle confinement time have been determined in TFR 600 by measuring the time evolution of plasma density and the flow rate of the injected neutral gas. Several conditioning methods of walls and chamber components are briefly described and the main results obtained with ohmic, neutral injection and R.F. heatings are summarized. For different types of experiments with pure plasmas, a global model can be used to describe the general recycling behavior of hydrogen isotopes and to obtain the recycling coefficient during a discharge. The effective particle life time and the total number of trapped particles in the inner wall are also directly obtained for each discharge. More than 50% of the injected gas is trapped during a discharge and released from the wall between two successive discharges. This low retention rate is indicative of the behavior of clean surfaces. The boundary plasma density and temperature are measured with Langmuir probes to determine the gross particle confinement time and the recycling rate of the walls. Hsub(α) measurements indicate a low ionization rate in the shadow of the limiter. The plasma edge temperature 14 cm -3 . In spite of the high recycling rate of deuterium atoms on the wall, low injection of light impurities are observed due to the poor oxygen and carbon contents of the surface. The radiation power is less than 30% of the total input power with 460 kW of injected R.F. power into the torus

A ‘Carbon Saving Multiplier’ as an alternative to rebound in considering reduced energy supply chain requirements from energy efficiency?

International Nuclear Information System (INIS)

Turner, Karen; Katris, Antonios

2017-01-01

A growing area of research into rebound effects from increased energy efficiency involves application of demand-driven input-output models to consider indirect energy consumption effects associated with re-spending decisions by households with reduced energy spending requirements. However, there is often a lack of clarity in applied studies as to how indirect effects involving energy use and/or carbon emissions in supply chains of both energy and non-energy goods and services have been calculated. We propose that more transparency for policymakers may be introduced by replacing consideration of what are often referred to as ‘indirect rebound’ effects with a simple Carbon Saving Multiplier metric. We illustrate using results from a demand-driven input-output model that tracks supply chain activity at national and/or global level. We argue that this captures and conveys the same information on quantity adjustments in energy used in supply chain activity but does so in a manner that is more positive, transparent, understandable and useful for a policy audience. This is achieved by focusing (here via carbon emissions) on the net benefits of changes in different types of energy use at both household and supply chain levels when energy efficiency improves in households. - Highlights: • Considers energy supply adjustments when household energy efficiency improves. • Focuses on energy supply chain impacts that may offset direct rebound effects. • Carbon Saving Multiplier proposed as a useful indicator of net energy use benefits.

Centralizing and decentralizing the system for unifying measurements on ionizing-radiation characteristics (medium-energy photon and charged-particle radiometry and spectrometry)

International Nuclear Information System (INIS)

Bregadze, Yu.I.; Stepanov, E.K.

1993-01-01

Ionizing-radiation applications have gradually defined the physical quantities needed to describe radiation sources, radiation as such, and interactions with matter. The optimum unit system has not yet been defined, since new regularities appear during research on the interactions of radiation with matter, and new relationships are being discovered between the radiation characteristics and the observed effects. There are 13 state primary standards in the measurement of ionizing radiation. Several of the standards reproduce the same unit but for different forms of radiation, while special standards reproduce units under special conditions. The present article discusses the various approaches to centralizing and decentralizing systems of supporting unified measurements for various ionizing-radiation characteristics. The three basic physical quantities used to characterize radioactive sources -- radionuclide activity, external particle emission, and particle energy -- are addressed separately. 10 refs

On the interpolation of light-scattering responses from irregularly shaped particles

Science.gov (United States)

Videen, Gorden; Zubko, Evgenij; Arnold, Jessica A.; MacCall, Benjamin; Weinberger, Alycia J.; Shkuratov, Yuriy; Muñoz, Olga

2018-05-01

Common particle characteristics needed for many applications may include size, eccentricity, porosity and refractive index. Determining such characteristics from scattered light is a primary goal of remote sensing. For other applications, like differentiating a hazardous particle from the natural background, information about higher fidelity particle characteristics may be required, including specific shape or chemical composition. While a complete characterization of a particle system from its scattered light through the inversion process remains unachievable, great strides have been made in providing information in the form of constraints on particle characteristics. Recent advances have been made in quantifying the characteristics of polydispersions of irregularly shaped particles by making comparisons of the light-scattering signals from model simulant particles. We show that when the refractive index is changed, the light-scattering characteristics from polydispersions of such particles behave monotonically over relatively large parameter ranges compared with those of monodisperse distributions of particles having regular shapes, like spheres, spheroids, etc. This allows for their properties to be interpolated, which results in a significant reduction of the computational load when performing inversions.

[A comparison of rebound tonometry (ICare) with TonoPenXL and Goldmann applanation tonometry].

Science.gov (United States)

Schreiber, W; Vorwerk, C K; Langenbucher, A; Behrens-Baumann, W; Viestenz, A

2007-04-01

Goldmann applanation tonometry and dynamic contour tonometry (PASCAL) are two well established slit lamp mounted tonometric methods. Intraocular pressure measurement in bedridden patients and children is often only possible using hand held tonometers (TonoPenXL, Perkins tonometer, Draeger tonometer). This study was performed to evaluate the hand held ICare tonometer, which is based on the rebound method. A total of 102 eyes were examined by two highly experienced ophthalmologists for: 1) ophthalmological status, 2) central corneal power (Zeiss IOL-Master), 3) central corneal thickness (Tomey ultrasound pachymetry, five successive measurements, SDr=0.592-0.642; p<0.001). There was a great intra-individual variability of up to 17 mmHg between the GAT, TonoPenXL and ICare methods. The ICare tonometer is easy to handle and high reliability. The data are comparable with those from the Goldmann tonometer. A tonography effect of 0.6 mmHg in the successive measurement series was found.

Microphysical characteristics of squall-line stratiform precipitation and transition zones inferred using an ice particle property-evolving model

Science.gov (United States)

Jensen, A. A.; Harrington, J. Y.; Morrison, H.

2017-12-01

A quasi-idealized 3D squall line (based on a June 2007 Oklahoma case) is simulated using a novel bulk microphysics scheme called the Ice-Spheroids Habit Model with Aspect-ratio Evolution (ISHMAEL). In ISHMAEL, the evolution of ice particle properties, such as mass, shape, maximum diameter, density, and fall speed, are tracked as these properties evolve from vapor growth, sublimation, riming, and melting. Thus, ice properties evolve from various microphysical processes without needing separate unrimed and rimed ice categories. Simulation results show that ISHMAEL produces both a squall-line transition zone and an enhanced stratiform precipitation region. The ice particle properties produced in this simulation are analyzed and compared to observations to determine the characteristics of ice that lead to the development of these squall-line features. It is shown that rimed particles advected rearward from the convective region produce the enhanced stratiform precipitation region. The development of the transition zone results from hydrometer sorting: the evolution of ice particle properties in the convective region produces specific fall speeds that favor significant ice advecting rearward of the transition zone before reaching the melting level, causing a local minimum in precipitation rate and reflectivity there. Microphysical sensitivity studies, for example turning rime splintering off, that lead to changes in ice particle properties reveal that the fall speed of ice particles largely determines both the location of the enhanced stratiform precipitation region and whether or not a transition zone forms.

Will the Steam Coal Price Rebound under the New Economy Normalcy in China?

Directory of Open Access Journals (Sweden)

Xiaopeng Guo

2016-09-01

Full Text Available The steam coal price in China has been continuously decreasing since the second half of 2012. Constant low price of coal will accelerate the development of thermal power, cause more serious air pollution problems, and bring adverse influence to China’s energy reformation in the future. Therefore, analyzing the factors underlying the phenomenon of the decreasing steam coal price is significant. In this study, we first qualitatively analyze five main factors, namely, economy, supply, demand, substitutes, and port stocks. On the basis of the relationships among these five factors, we obtain the causality diagram and the system flow diagram of coal price for further quantitative research. Then, we conduct an empirical analysis using the system dynamics (SD method and determine the simulated price from 2012 to 2017. Finally, we discuss the running results and come to the conclusion that the steam coal price will continue to decrease under the combined actions of the five main factors and it will not rebound in the near future.

Particle creation by peak electric field

Energy Technology Data Exchange (ETDEWEB)

Adorno, T.C. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); Gavrilov, S.P. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); Herzen State Pedagogical University of Russia, Department of General and Experimental Physics, St. Petersburg (Russian Federation); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); P. N. Lebedev Physical Institute, Moscow (Russian Federation); University of Sao Paulo, Institute of Physics, CP 66318, Sao Paulo, SP (Brazil)

2016-08-15

The particle creation by the so-called peak electric field is considered. The latter field is a combination of two exponential parts, one exponentially increasing and another exponentially decreasing. We find exact solutions of the Dirac equation with the field under consideration with appropriate asymptotic conditions and calculate all the characteristics of particle creation effect, in particular, differential mean numbers of created particle, total number of created particles, and the probability for a vacuum to remain a vacuum. Characteristic asymptotic regimes are discussed in detail and a comparison with the pure asymptotically decaying field is considered. (orig.)

Acceleration Characteristics of a Rock Slide Using the Particle Image Velocimetry Technique

Directory of Open Access Journals (Sweden)

Guoqing Chen

2016-01-01

Full Text Available The Particle Image Velocimetry (PIV technique with high precision and spatial resolution is a suitable sensor for flow field experiments. In this paper, the PIV technology was used to monitor the development of a displacement field, velocity field and acceleration field of a rock slide. It was found that the peak acceleration of the sliding surface appeared earlier than the peak acceleration of the sliding body. The characteristics of the rock slide including the short failure time, high velocities, and large accelerations indicate that the sliding forces and energy release rate of the slope are high. The deformation field showed that the sliding body was sliding outwards along the sliding surface while the sliding bed moved in an opposite direction. Moving upwards at the top of the sliding bed can be one of the warning signs for rock slide failure.

Characterization of Mechanical Properties of Marble sludge/natural rubber composites

International Nuclear Information System (INIS)

Bhatti, K.P.

2012-01-01

This study aims to investigate the possible utilization of Marble Sludge (MS) in Natural Rubber (NR) composites, which would reduce both the environmental pollution and product cost. Marble waste in the form of sludge is taken from Mangopir Marble industrial area Karachi. The sludge was dried, grinded and passed through desire sieves (20, 37 and 75 micro m) and incorporated in the formulation of NR composites. The physical characteristics of dry MS were carried out in order to identify all components by instrumental techniques. Different micro sized particles of MS (20, 37 and 75 micro-m) were added with different loading (10, 30, 50, 70 and 90 phr). Mechanical properties of MS filled NR composites were studied. It was found that tensile strength and tear strength increased with increasing the MS till 70 phr. Further addition of MS in the composites decreased both strengths. Elongation at break and rebound resilience decreased with increasing MS loading, while modulus, (100%, 200% and 300% elongation), hardness, compression set and abrasion loss increased with increase loading of MS. All mechanical properties of smaller micro size MS particle (20 micro-m) filled NR composites have higher values then 37 and 75 micro-m size particle. The results of mechanical properties after aging show that the tensile strength, modulus, elongation at break and rebound resilience values decreased while hardness, compression set and abrasion loss values increased. (author)

Effects of supplementation level and particle size of alfalfa hay on growth characteristics and rumen development in dairy calves

NARCIS (Netherlands)

Mirzaei, M.; Khorvash, M.; Ghorbani, G.R.; Kazemi-Bonchenari, M.; Riasi, A.; Nabipour, A.; Borne, van den J.J.G.C.

2015-01-01

The aim of this study was to assess the effects of particle size (PS) of alfalfa hay on growth characteristics and rumen development in dairy calves at two levels of alfalfa supplementation. Fifty newborn dairy calves (42.7 ± 2.2 kg BW) were used in a 2 × 2 factorial arrangement with the factors

Lunar Regolith Particle Shape Analysis

Science.gov (United States)

Kiekhaefer, Rebecca; Hardy, Sandra; Rickman, Douglas; Edmunson, Jennifer

2013-01-01

Future engineering of structures and equipment on the lunar surface requires significant understanding of particle characteristics of the lunar regolith. Nearly all sediment characteristics are influenced by particle shape; therefore a method of quantifying particle shape is useful both in lunar and terrestrial applications. We have created a method to quantify particle shape, specifically for lunar regolith, using image processing. Photomicrographs of thin sections of lunar core material were obtained under reflected light. Three photomicrographs were analyzed using ImageJ and MATLAB. From the image analysis measurements for area, perimeter, Feret diameter, orthogonal Feret diameter, Heywood factor, aspect ratio, sieve diameter, and sieve number were recorded. Probability distribution functions were created from the measurements of Heywood factor and aspect ratio.

Potential Selection Effects when Estimating Associations Between the Infancy Peak or Adiposity Rebound and Later Body Mass Index in Children

DEFF Research Database (Denmark)

Börnhorst, Claudia; Siani, Alfonso; Tornaritis, Michalis

2017-01-01

Introduction:This study aims to evaluate a potential selection effect caused by exclusion of children with non-identifiable infancy peak (IP) and adiposity rebound (AR) when estimating associations between age and BMI at IP and AR and later weight status. Subjects and methods: In 4 744 children.......98). In the total study group, BMI values in infancy and childhood were positively associated with later BMI z-scores where associations increased with age. Associations between BMI velocities and later BMI z-scores were largest at ages 5 and 6. Results differed for children with non-identifiable IP and AR...

Growth mechanism, distribution characteristics and reinforcing behavior of (Ti, Nb)C particle in laser cladded Fe-based composite coating

International Nuclear Information System (INIS)

Li, Qingtang; Lei, Yongping; Fu, Hanguang

2014-01-01

Highlights: • Reinforced (Ti, Nb)Cp can be synthesized in the molten pool during laser cladding. • Formation mechanism of (Ti, Nb)Cp are impacted by Ti/Nb atomic ratio. • Appropriate Ti element can improve the precipitation of carbide particle. • Excess Ti weakens this effect above-mentioned. • The wear resistance of the coating was improved when Ti/Nb = 1. - Abstract: Over the past decade, researchers have demonstrated much interest in laser cladded metal matrix composite coatings for its good wear resistance, corrosion resistance, and high temperature properties. In this paper, in-situ (Ti, Nb)C particle reinforced Fe-based composite coatings were produced by laser cladding. The effects of Ti/Nb(atomic ratio) in the cladding powder on the formation mechanism and distribution characteristics of multiple particle were investigated. The results showed that when Ti/Nb > 1, Ti had a stronger ability to bond with C compared with Nb. (Ti, Nb)C multiple particles with TiC core formed in the molten pool. With the decrease of Ti/Nb, core-shell structure disappeared, the structure of particle got close to that of NbC gradually. It is found that the amount, area ratio and distribution of the reinforced particle in the coating containing Ti and Nb elements were improved, compared with these in the coating containing equal Nb element. When Ti/Nb = 1, the effects above-mentioned is most prominent, and the wear resistance of the coating is promoted obviously

Growth mechanism, distribution characteristics and reinforcing behavior of (Ti, Nb)C particle in laser cladded Fe-based composite coating

Energy Technology Data Exchange (ETDEWEB)

Li, Qingtang, E-mail: liqingtang123@126.com; Lei, Yongping, E-mail: yplei@bjut.edu.cn; Fu, Hanguang

2014-10-15

Highlights: • Reinforced (Ti, Nb)Cp can be synthesized in the molten pool during laser cladding. • Formation mechanism of (Ti, Nb)Cp are impacted by Ti/Nb atomic ratio. • Appropriate Ti element can improve the precipitation of carbide particle. • Excess Ti weakens this effect above-mentioned. • The wear resistance of the coating was improved when Ti/Nb = 1. - Abstract: Over the past decade, researchers have demonstrated much interest in laser cladded metal matrix composite coatings for its good wear resistance, corrosion resistance, and high temperature properties. In this paper, in-situ (Ti, Nb)C particle reinforced Fe-based composite coatings were produced by laser cladding. The effects of Ti/Nb(atomic ratio) in the cladding powder on the formation mechanism and distribution characteristics of multiple particle were investigated. The results showed that when Ti/Nb > 1, Ti had a stronger ability to bond with C compared with Nb. (Ti, Nb)C multiple particles with TiC core formed in the molten pool. With the decrease of Ti/Nb, core-shell structure disappeared, the structure of particle got close to that of NbC gradually. It is found that the amount, area ratio and distribution of the reinforced particle in the coating containing Ti and Nb elements were improved, compared with these in the coating containing equal Nb element. When Ti/Nb = 1, the effects above-mentioned is most prominent, and the wear resistance of the coating is promoted obviously.

Hydrodynamic characteristics of a two-phase gas-liquid flow upward through a fixed bed of spherical particles

Directory of Open Access Journals (Sweden)

VELIZAR D. STANKOVIC

2001-01-01

Full Text Available The influence of an electrochemically generated gas phase on the hydrodynamic characteristics of a three-phase system has been examined. The two-phase fluid, (gas-liquid, in which the liquid phase is the continuous one, flows through a packed bed with glass spheres. The influence of the liquid velocity was examined, as well as the gas velocity and particle diameter on the pressure drop through the fixed bed. It was found that with increasing liquid velocity (wl = 0.0162–0.03 m/s, the relative pressure drop decreases through the fixed bed. With increasing current density, the pressure drop increases, since greater gas quantities stay behind in the fixed bed. Besides, it was found that with decreasing diameter of the glass particles, the relative pressure drop also decreases. The relationship betweeen the experimentally obtained friction factor and the Reynolds number was established.

Wear Characteristics of Hybrid Composites Based on Za27 Alloy Reinforced With Silicon Carbide and Graphite Particles

Directory of Open Access Journals (Sweden)

S. Mitrović

2014-06-01

Full Text Available The paper presents the wear characteristics of a hybrid composite based on zinc-aluminium ZA27 alloy, reinforced with silicon-carbide and graphite particles. The tested sample contains 5 vol.% of SiC and 3 vol.% Gr particles. Compocasting technique has been used to prepare the samples. The experiments were performed on a “block-on-disc” tribometer under conditions of dry sliding. The wear volumes of the alloy and the composite were determined by varying the normal loads and sliding speeds. The paper contains the procedure for preparation of sample composites and microstructure of the composite material and the base ZA27 alloy. The wear surface of the composite material was examined using the scanning electronic microscope (SEM and energy dispersive spectrometry (EDS. Conclusions were obtained based on the observed impact of the sliding speed, normal load and sliding distance on tribological behaviour of the observed composite.

Fouling deposition characteristic by variation of coal particle size and deposition temperature in DTF (Drop Tube Furnace)

Energy Technology Data Exchange (ETDEWEB)

Namkung, Hueon; Jeon, Youngshin; Kim, Hyungtaek [Ajou Univ., Suwon (Korea, Republic of). Div. of Energy Systems Research; Xu, Li-hua [IAE, Suwon (Korea, Republic of). Plant Engineering Center

2013-07-01

One of the major operation obstacles in gasification process is ash deposition phenomenon. In this investigation, experiment was carried out to examine coal fouling characteristics using a laminar DTF (Drop Tube Furnace) with variation of operating condition such as different coal size, and probe surface temperature. Four different samples of pulverized coal were injected into DTF under various conditions. The ash particles are deposited on probe by impacting and agglomerating action. Fouling grains are made of eutectic compound, which is made by reacting with acid minerals and alkali minerals, in EPMA (Electron Probe Micro-Analysis). And agglomeration area of fouling at top layer is wide more than it of middle and bottom layer. The major mineral factors of fouling phenomenon are Fe, Ca, and Mg. The deposition quantity of fouling increases with increasing particle size, high alkali mineral (Fe, Ca, and Mg) contents, and ash deposition temperature.

Early adiposity rebound: causes and consequences for obesity in children and adults.

Science.gov (United States)

Rolland-Cachera, M F; Deheeger, M; Maillot, M; Bellisle, F

2006-12-01

Childhood obesity is an important public health problem, with a rapidly increasing frequency worldwide. Identification of critical periods for the development of childhood and adolescent obesity could be very useful for targeting prevention measures. Weight status in early childhood is a poor predictor of adult adiposity status, and most obese adults were not obese as children. We first proposed to use the body mass index (BMI) charts to monitor individual BMI development. The adiposity rebound (AR) corresponds to the second rise in BMI curve that occurs between ages 5 and 7 years. It is not as direct a measure as BMI at any age, but because it involves the examination of several points during growth, and because it is identified at a time when adiposity level clearly change directions, this method provides information that can help us understand individual changes and the development of health risks. An early AR is associated with an increased risk of overweight. It is inversely associated with bone age, and reflects accelerated growth. The early AR recorded in most obese subjects and the striking difference in the mean age at AR between obese subjects (3 years) and non-obese subjects (6 years) suggest that factors have operated very early in life. The typical pattern associated with an early AR is a low BMI followed by increased BMI level after the rebound. This pattern is recorded in children of recent generations as compared to those of previous generations. This is owing to the trend of a steeper increase of height as compared to weight in the first years of life. This typical BMI pattern (low, followed by high body fatness level) is associated with metabolic diseases such as diabetes and coronary heart diseases. Low body fatness before the AR suggests that an energy deficit had occurred at an early stage of growth. It can be attributable to the high-protein, low-fat diet fed to infants at a time of high energy needs, the former triggering height velocity and

Particle sizing experiments with the laser Doppler velocimeter: Final report

Energy Technology Data Exchange (ETDEWEB)

Giel, T.V. Jr.; Son, J.Y.

1988-06-01

Measurement techniques for in-situ simultaneous measurements of particle size distributions and particle velocities using the dual beam laser Doppler velocimeter (LV) were analytically and experimentally investigated. This investigation examined the different signal characteristics of the LV for determination of particle size and particle velocity, simultaneously. The different size related signal components were evaluated not only singularly but also as simultaneous measurements to determine which characteristic, or combination of characteristics, provided the best measure of particle size. The evaluation concentrated on the 0.5 to 5 ..mu..m particle size range, in which the LV light scattering characteristics are complex often non-monotonic functions of the particle size as well as functions of index of refraction, the laser light wavelength, laser intensity and polarization, and the location and response characteristics of the detector. Different components of the LV signal were considered, but analysis concentrated on Doppler phase, visibility and scatter-intensity because they show the greatest promise. These signals characteristics were initially defined analytically for numerous optical configurations over the 0.5 to 5 ..mu..m diameter range with 0.1 ..mu..m segmentation, for refractive index values from 1.0 to 3.0 with absorptive (imaginary) components varied form 0 to 1.0. Collector orientation and effective f/No., as well as fringe spacing, beam polarization and wavelength, were varied in this analytical evaluation. 18 refs., 42 figs., 5 tabs.

Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

Science.gov (United States)

Alanen, Jenni; Simonen, Pauli; Saarikoski, Sanna; Timonen, Hilkka; Kangasniemi, Oskari; Saukko, Erkka; Hillamo, Risto; Lehtoranta, Kati; Murtonen, Timo; Vesala, Hannu; Keskinen, Jorma; Rönkkö, Topi

2017-07-01

measured to have the highest evaporation temperature, and nitrate had the lowest. The evaporation temperature of ammonium depended on the fractions of nitrate and sulfate in the particles. The average volatility of the total aged particles was measured to be lower than that of primary particles, indicating better stability of the aged natural gas engine-emitted aerosol in the atmosphere. According to the results of this study, the exhaust of a natural gas engine equipped with a catalyst forms secondary aerosol when the atmospheric ages in a PAM chamber are several days long. The secondary aerosol matter has different physical characteristics from those of primary particulate emissions.

Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

Directory of Open Access Journals (Sweden)

J. Alanen

2017-07-01

source and system temperatures. Sulfate was measured to have the highest evaporation temperature, and nitrate had the lowest. The evaporation temperature of ammonium depended on the fractions of nitrate and sulfate in the particles. The average volatility of the total aged particles was measured to be lower than that of primary particles, indicating better stability of the aged natural gas engine-emitted aerosol in the atmosphere. According to the results of this study, the exhaust of a natural gas engine equipped with a catalyst forms secondary aerosol when the atmospheric ages in a PAM chamber are several days long. The secondary aerosol matter has different physical characteristics from those of primary particulate emissions.

Characteristic fly-ash particles from oil-shale combustion found in lake sediments

International Nuclear Information System (INIS)

Alliksaar, T.; Hoerstedt, P.; Renberg, I.

1998-01-01

Fly-ash particles accumulate in sediments and can be used to assess spatial distribution and temporal trends of atmospheric deposition of pollutants derived from high temperature combustion of fossil fuels. Previous work has concerned fly-ash derived from oil and coal. Oil-shale is the main fossil fuel used in Estonia and a major source of atmospheric pollution in the Baltic states. To assess if oil-shale power plants produce specific fly-ash particles scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to compare fly-ash particles from oil-shale combustion with particles from oil and coal combustion. Two types were analysed, large black (10-30μm) and small glassy (< 5 μm) spheroidal particles. Although article morphology to some extent is indicative of the fuel burnt, morphological characters are not sufficient to differentiate between particles of different origin. However, the results indicate that with EDX analysis the fly-ash from oil-shale can be distinguished form oil and coal derived particles in environmental samples. Concentrations of large black and small glassy spheroidal fly-ash particles in a sediment core from an Estonian lake showed similar trends to oil-shale combustion statistics from Estonian power plants. 27 refs., 6 figs., 2 tabs

Measurement of flow characteristics of solid particles mixed with gas in pipelines

Energy Technology Data Exchange (ETDEWEB)

Siberev, S P; Nazarov, S I; Soldatkin, G I

1983-01-01

A mathematical model of the interaction of solid particles in a gas stream flowing through a pipeline comprises equations for the energy and material balances in the system and for force and energy interactions between the solid particles and transducers located within the pipeline. Soviet researchers confirmed that the average value of stress recorded by a transducer is proportional to the average kinetic energy of the particles; for a constant particle speed, the stress is proportional to the mass flow of the particles. The analysis and flow transducer measurements are valuable in measuring and controlling flowline sand and soil in natural gas transport from gas wells and undergound storage facilities.

Physical characterization of diesel exhaust nucleation mode particles

Energy Technology Data Exchange (ETDEWEB)

Lahde, T.

2013-11-01

An increasing concern of the adverse health effects of aerosol particles is forcing the combustion engine industry to develop engines with lower particle emissions. The industry has put most of their efforts into soot control and has achieved a significant reduction in diesel exhaust particle mass. Nevertheless, it is not clear that the large particles, dominating the mass, cause the harmfulness of the exhaust particles in the biological interaction. Nowadays, the harmful potential of diesel exhaust particles often connects with the particle surface area, and the view has turned to particle number below 100 nm size range. Unfortunately, the achieved low exhaust particle mass does not necessarily imply a low particle number. This text focuses on the physical characteristics of diesel exhaust nucleation model particles. The volatility characteristics and the electrical charge state of the particles are studied first. Second, the relation between the nonvolatile nucleation mode emissions and the soot, the nitrogen oxide (NO{sub x}) emissions and the engine parameters are covered. The nucleation mode particles had distinctively different physical characteristics with different after-treatment systems. The nucleation mode was volatile and electrically neutral with a diesel particle filter after-treatment system. Without an after-treatment system or with an after-treatment system with low particle removal efficiency, the nucleation mode was partly nonvolatile and included an electrical charge. The difference suggests different formation routes for the nucleation particles with different after-treatment systems. The existence of the nonvolatile nucleation mode particles also affected the soot mode charge state. The soot charge state was positively biased when the nonvolatile nucleation mode was detected but slightly negatively biased when the nonvolatile nucleation mode was absent. The nonvolatile nucleation mode was always negatively biased. This electrical charge

A FDTD solution of scattering of laser beam with orbital angular momentum by dielectric particles: Far-field characteristics

Science.gov (United States)

Sun, Wenbo; Hu, Yongxiang; Weimer, Carl; Ayers, Kirk; Baize, Rosemary R.; Lee, Tsengdar

2017-02-01

Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre-Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam's interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of 15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles.

Physicochemical characteristics of aerosol particles generated during the milling of beryllium silicate ores: implications for risk assessment.

Science.gov (United States)

Stefaniak, Aleksandr B; Chipera, Steve J; Day, Gregory A; Sabey, Phil; Dickerson, Robert M; Sbarra, Deborah C; Duling, Mathew G; Lawrence, Robert B; Stanton, Marcia L; Scripsick, Ronald C

2008-01-01

Inhalation of beryllium dusts generated during milling of ores and cutting of beryl-containing gemstones is associated with development of beryllium sensitization and low prevalence of chronic beryllium disease (CBD). Inhalation of beryllium aerosols generated during primary beryllium production and machining of the metal, alloys, and ceramics are associated with sensitization and high rates of CBD, despite similar airborne beryllium mass concentrations among these industries. Understanding the physicochemical properties of exposure aerosols may help to understand the differential immunopathologic mechanisms of sensitization and CBD and lead to more biologically relevant exposure standards. Properties of aerosols generated during the industrial milling of bertrandite and beryl ores were evaluated. Airborne beryllium mass concentrations among work areas ranged from 0.001 microg/m(3) (beryl ore grinding) to 2.1 microg/m(3) (beryl ore crushing). Respirable mass fractions of airborne beryllium-containing particles were 80% in high-energy input areas (beryl melting, beryl grinding). Particle specific surface area decreased with processing from feedstock ores to drumming final product beryllium hydroxide. Among work areas, beryllium was identified in three crystalline forms: beryl, poorly crystalline beryllium oxide, and beryllium hydroxide. In comparison to aerosols generated by high-CBD risk primary production processes, aerosol particles encountered during milling had similar mass concentrations, generally lower number concentrations and surface area, and contained no identifiable highly crystalline beryllium oxide. One possible explanation for the apparent low prevalence of CBD among workers exposed to beryllium mineral dusts may be that characteristics of the exposure material do not contribute to the development of lung burdens sufficient for progression from sensitization to CBD. In comparison to high-CBD risk exposures where the chemical nature of aerosol

Particle correlations at ALICE

Energy Technology Data Exchange (ETDEWEB)

Erazmus, B.; Lednicky, R.; Lyuboshitz, V.; Martin, L.; Mikhailov, K.; Pluta, J.; Sinyukov, Yu.; Stavinsky, A.; Werner, K

1998-12-31

The ability of the ALICE detector for determination of the space-time characteristics of particle production in heavy-ion collisions at LHC from measurements of the correlation functions of identical and non-identical particles at small relative velocities is discussed. The possibility to use the correlations of non-identical particles for a direct determination of the delays in emission of various particle species at time scales as small as 10{sup -23} s is demonstrated. The influence of the multi-boson effects on pion multiplicities, single-pion spectra and two-pion correlation functions is discussed. (author) 63 refs.

Trajectory traces of charged particles in the magnetosphere

International Nuclear Information System (INIS)

Ejiri, M.

1978-01-01

The characteristic enhancements of ring current particles with energies of about 1--1000keV, associated with magnetospheric substorms, were observed by Explorer 45 (S 3 -A) around the plasmapause in the afternoon to midnight region and showed the characteristic structure called a 'noise' in the proton spectrograms. This paper examines the time developing characteristics of newly injected particles in the magnetosphere under a recently proposed convection electric field and a dipole magnetic field. Approximate equations of a bounce period, a second adiabatic invariant, and a bounce-averaged azimuthal velocity are given with an error of less than about 10 -3 for all pitch angles. The complete set of flow patterns of 90 0 pitch angles is also described by means of inflection lines through whicch radial and/or azimuthal drifts change their directions and where particle velocities show their local minima, i.e., the flow becomes sluggish. These particle tracings in the magnetosphere, from which time dependent particle fronts can be constructed, give the basic concept and mechanics to explain the complex and dynamical properties of the magnetic storm time particle enhancements

A FDTD solution of scattering of laser beam with orbital angular momentum by dielectric particles: Far-field characteristics

International Nuclear Information System (INIS)

Sun, Wenbo; Hu, Yongxiang; Weimer, Carl; Ayers, Kirk; Baize, Rosemary R.; Lee, Tsengdar

2017-01-01

Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre–Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam's interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of ~15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles. - Highlights: • Scattering of orbital angular momentum (OAM) laser beam by dielectric

Blocking Indolamine-2,3-Dioxygenase Rebound Immune Suppression Boosts Antitumor Effects of Radio-Immunotherapy in Murine Models and Spontaneous Canine Malignancies.

Science.gov (United States)

Monjazeb, Arta M; Kent, Michael S; Grossenbacher, Steven K; Mall, Christine; Zamora, Anthony E; Mirsoian, Annie; Chen, Mingyi; Kol, Amir; Shiao, Stephen L; Reddy, Abhinav; Perks, Julian R; T N Culp, William; Sparger, Ellen E; Canter, Robert J; Sckisel, Gail D; Murphy, William J

2016-09-01

Previous studies demonstrate that intratumoral CpG immunotherapy in combination with radiotherapy acts as an in-situ vaccine inducing antitumor immune responses capable of eradicating systemic disease. Unfortunately, most patients fail to respond. We hypothesized that immunotherapy can paradoxically upregulate immunosuppressive pathways, a phenomenon we term "rebound immune suppression," limiting clinical responses. We further hypothesized that the immunosuppressive enzyme indolamine-2,3-dioxygenase (IDO) is a mechanism of rebound immune suppression and that IDO blockade would improve immunotherapy efficacy. We examined the efficacy and immunologic effects of a novel triple therapy consisting of local radiotherapy, intratumoral CpG, and systemic IDO blockade in murine models and a pilot canine clinical trial. In murine models, we observed marked increase in intratumoral IDO expression after treatment with radiotherapy, CpG, or other immunotherapies. The addition of IDO blockade to radiotherapy + CpG decreased IDO activity, reduced tumor growth, and reduced immunosuppressive factors, such as regulatory T cells in the tumor microenvironment. This triple combination induced systemic antitumor effects, decreasing metastases, and improving survival in a CD8(+) T-cell-dependent manner. We evaluated this novel triple therapy in a canine clinical trial, because spontaneous canine malignancies closely reflect human cancer. Mirroring our mouse studies, the therapy was well tolerated, reduced intratumoral immunosuppression, and induced robust systemic antitumor effects. These results suggest that IDO maintains immune suppression in the tumor after therapy, and IDO blockade promotes a local antitumor immune response with systemic consequences. The efficacy and limited toxicity of this strategy are attractive for clinical translation. Clin Cancer Res; 22(17); 4328-40. ©2016 AACR. ©2016 American Association for Cancer Research.

Scattering by ensembles of small particles

International Nuclear Information System (INIS)

Gustafson, B. Aa. S.

1980-11-01

With the advent of high altitude rockets and of space probes, evidence has accumulated that several particle types coexiste in the interplanetary medium. It also became apparent that the zodiacal light is not produced by particles with previously known scattering characteristics. However, the scattering is here shown to be consistent with the hypothesis that presolar interstellar grains accumulate into comets which through fragmentation provide a major component of the interplanetary dust complex. Cometary debris - zodiscal light particles - are therefore modeled as conglomerates of elongated core-mantle particles. Light scattering characteristics of the conglomerates are investigated using a micro-wave analogue method. Approximate theoretical methods for prediction and interpretation of the electro-magnetic scattering patterns are developed and are found to compare favorably with the experimental results and with observations of the zodiacal light. The model is also found to be consistent with comet- and impactdata. Dynamical considerations predicts a small particle component rapidly receding from the Sun, an identification with the B-meteoroids is tentatively suggested. (author)

The delusion of decoupling, and policy options for mitigating the rebound effect and the environmental impact

DEFF Research Database (Denmark)

Nørgaard, Jørgen

reduce, or at least limit, ‘P’ and ‘A’, including their rebound growth from the ‘T’ decrease. The paper suggest this to be achievable in affluent countries, by letting ‘P’ decline through low birth rates, and encouraging ‘A’ to decline in exchange for lowering labor input to the economy, partly......When analyzing environmental problems, it is useful to apply the following simple equation for the environmental impact ‘I’, (here representing energy consumption): I = P·A·T, With ‘P’ representing population, ‘A’ affluence per capita, and ‘T’ resource intensity, i.e. energy per affluence unit ‘A......’. All three factors are through the equation coupled to ‘I’, and in general we should avoid using the misleading terminology of decoupling environmental impact (energy consumption) from the economy, represented by ‘P·A’. So far essentially all policies towards lowering ‘I’ has been devoted towards...

The determinants of fuel use in the trucking industry – volume, size and the rebound effect

DEFF Research Database (Denmark)

Mulalic, Ismir

2011-01-01

We analyse the determinants of trucking firm fuel use. We develop a simple model to show that trucking firm fuel use depends, in addition to the fuel price and the traffic volume, also on the output of the trucking firm’s production process (the movement of cargo) measured in tonkilometres...... these elasticities using a simultaneous-equation model based on aggregate time-series data for Denmark for 1980-2007. Our best estimates of the short run and the long run rebound effects for road freight transportation are 19% and 28%, respectively. We also find that an increase in the fuel price surprisingly has...... a small but significant negative effect on the fuel efficiency (measured here as vehicle kilometres travelled (VKT) per litre of consumed fuel), i.e. a 1% increase in the fuel price decreases the fuel efficiency by 0.13% in the long run. However, less distance has to be driven for the same payload. An 1...

Spheronization process particle kinematics determined by discrete element simulations and particle image velocimentry measurements.

Science.gov (United States)

Koester, Martin; García, R Edwin; Thommes, Markus

2014-12-30

Spheronization is an important pharmaceutical manufacturing technique to produce spherical agglomerates of 0.5-2mm diameter. These pellets have a narrow size distribution and a spherical shape. During the spheronization process, the extruded cylindrical strands break in short cylinders and evolve from a cylindrical to a spherical state by deformation and attrition/agglomeration mechanisms. Using the discrete element method, an integrated modeling-experimental framework is presented, that captures the particle motion during the spheronization process. Simulations were directly compared and validated against particle image velocimetry (PIV) experiments with monodisperse spherical and dry γ-Al2O3 particles. demonstrate a characteristic torus like flow pattern, with particle velocities about three times slower than the rotation speed of the friction plate. Five characteristic zones controlling the spheronization process are identified: Zone I, where particles undergo shear forces that favors attrition and contributes material to the agglomeration process; Zone II, where the static wall contributes to the mass exchange between particles; Zone III, where gravitational forces combined with particle motion induce particles to collide with the moving plate and re-enter Zone I; Zone IV, where a subpopulation of particles are ejected into the air when in contact with the friction plate structure; and Zone V where the low poloidal velocity favors a stagnant particle population and is entirely controlled by the batch size. These new insights in to the particle motion are leading to deeper process understanding, e.g., the effect of load and rotation speed to the pellet formation kinetics. This could be beneficial for the optimization of a manufacturing process as well as for the development of new formulations. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in cyclone heat exchanger

International Nuclear Information System (INIS)

Mothilal, T.; Pitchandi, K.

2015-01-01

Present work elaborates the effect of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in a cyclone heat exchanger. The RNG k-ε turbulence model was adopted for modeling high turbulence flow and Discrete phase model (DPM) to track solid particles in a cyclone heat exchanger by ANSYS FLUENT software. The effect of inlet air velocity (5 to 25 m/s) and inlet solid particle feed rate of (0.2 to 2.5 g/s) at different particle diameter (300 to 500 μm) on holdup mass and heat transfer rate in cyclone heat exchanger was studied at air inlet temperature of 473 K. Results show that holdup mass and heat transfer rate increase with increase in inlet air velocity and inlet solid particle feed rate. Influence of solid particle feed rate on holdup mass has more significance. Experimental setup was built for high efficiency cyclone. Good agreement was found between experimental and simulation pressure drop. Empirical correlation was derived for dimensionless holdup mass and Nusselt number based on CFD data by regression technique. Correlation predicts dimensional holdup mass with +5% to -8% errors of experimental data and Nusselt number with +9% to -3%

Influence of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in cyclone heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Mothilal, T. [T. J. S. Engineering College, Gummidipoond (India); Pitchandi, K. [Sri Venkateswara College of Engineering, Sriperumbudur (India)

2015-10-15

Present work elaborates the effect of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in a cyclone heat exchanger. The RNG k-ε turbulence model was adopted for modeling high turbulence flow and Discrete phase model (DPM) to track solid particles in a cyclone heat exchanger by ANSYS FLUENT software. The effect of inlet air velocity (5 to 25 m/s) and inlet solid particle feed rate of (0.2 to 2.5 g/s) at different particle diameter (300 to 500 μm) on holdup mass and heat transfer rate in cyclone heat exchanger was studied at air inlet temperature of 473 K. Results show that holdup mass and heat transfer rate increase with increase in inlet air velocity and inlet solid particle feed rate. Influence of solid particle feed rate on holdup mass has more significance. Experimental setup was built for high efficiency cyclone. Good agreement was found between experimental and simulation pressure drop. Empirical correlation was derived for dimensionless holdup mass and Nusselt number based on CFD data by regression technique. Correlation predicts dimensional holdup mass with +5% to -8% errors of experimental data and Nusselt number with +9% to -3%.

14C-labeled diesel exhaust particles: chemical characteristics and bioavailability studies

International Nuclear Information System (INIS)

Sun, J.D.; Wolff, R.K.; Dutcher, J.S.; Brooks, A.L.

1981-01-01

Little is known about the deposition, retention and biological fate of the organic compounds associated with diesel exhaust particles. In the studies reported here, a one-cylinder diesel engine was operated on diesel fuel spiked with 14 C-benzene, 14 C-hexadecane or 14 C-dotriacontane to generate 14 C-labeled diesel exhaust. Approximately 1% of the exhaust radioactivity was associated with the particulate phase of diesel exhaust. Chemical fractionation of the particle extract showed the 14 C to be present in each of the various chemical class fractions collected. Serum removed approx. 60% of the dichloromethane extractable radioactivity from these diesel particles while saline removed only approx. 6%. This suggested that the organic compounds may be removed from diesel particles in vivo. Future inhalation exposures of rodents to 14 C-labeled diesel exhausts are planned to gain additional information on the health risk of human exposure to diesel exhaust

Method of determining the characteristics of circulatory systems using tracer particles, making the particles and radioactive particles for use in the method

International Nuclear Information System (INIS)

Pratt, F.P.; Gagnon, D.L.

1981-01-01

In the method described tracer particles consist of ion exchange resin cores labelled with suitable radioactive ions or with a nuclide excitable by X-rays, and have a non-leaching polymeric coating. The particles are introduced into the system and are detected by visual inspection, radiation detection or X-ray fluorescence techniques. The cores are labelled using conventional batch ion exchange techniques. Coated tracers are produced by contacting a monomer, preferably furfuryl alcohol, with cores bearing catalytic ions (hydroxyl or hydrogen) on the surface which catalyse the monomer to form a polymer. The tracer particles in a physiologically acceptable liquid carrier are useful in clinical and medical investigations of blood flow. They can also be used for flow measurement in chemical process control streams. (U.K.)

Effect of raw material particle-size distribution on combustion characteristics of stem wood pellets; Paaverkan av partikelfraktionsfoerdelningen paa utbraenningshastigheten hos traepellets vid nyttjande av olika soenderdelningsmetoder

Energy Technology Data Exchange (ETDEWEB)

Israelsson, Samuel; Henriksson, Gunnar; Boman, Christoffer; Oehman, Marcus

2007-01-15

The objective of the project was to determine the effect of raw material particle-size distribution on combustion characteristics of stem wood pellets. Several well defined pellet qualities were produced from raw materials (stem wood of pine and spruce) which had both different particle-size distributions and were produced with different milling equipments (hammer mill/refiner). The pellets were produced in a traditional (bench-scale) pellet mill and in a laboratory pellet mill/press. The combustion characteristics of the individual pellets were determined in a laboratory scale oven. Char yield, -shrinkage, -density and the micro pore volume of the produced char were also determined. Differences in total conversion times of approximately 5 % at experimental condition relevant for typical pellets equipment were determined for the different pellet qualities. The underlying reasons for the obtained differences in the combustion characteristics between the different pellet qualities are discussed in the report

Cavitation structures formed during the rebound of a sphere from a wetted surface

KAUST Repository

Marston, Jeremy; Wang, Yong; Ng, Waikiong; Tan, Reginald; Thoroddsen, Sigurdur T

2010-01-01

We use high-speed imaging to observe the dynamics of cavitation, caused by the impact and subsequent rebound of a sphere from a solid surface covered with a thin layer of highly viscous liquid. We note marked qualitative differences between the cavitation structures with increase in viscosity, as well as between Newtonian and non-Newtonian liquids. The patterns observed are quite unexpected and intricate, appearing in concentric ring formations around the site of impact. In all cases, we identify a distinct radius from which the primary bubbles emanate. This radius is modelled with a modified form of Hertz contact theory. Within this radius, we show that some fine cavitation structure may exist or that it may be one large cavitation bubble. For the non-Newtonian fluids, we observe foam-like structures extending radially with diminishing bubble sizes with increase in radial position. Whereas for the Newtonian fluids, the opposite trend is observed with increasing bubble size for increasing radial position. Finally, we compare our experimental observations of cavitation to the maximum tension criterion proposed by Joseph (J Fluid Mech 366:367-378, 1998) showing that this provides the lower limit for the onset of cavitation in our experiments. © 2010 Springer-Verlag.

Rebound boots change lower limb muscle activation and kinematics during different fitness exercises.

Science.gov (United States)

Rossato, Mateus; Dellagrana, Rodolfo André; Dos Santos, Juliane Cristine Lopes; Carpes, Felipe P; Gheller, Rodrigo Ghedini; da Silva, De Angelys de Ceselles Seixas; Bezerra, Ewertton de Souza; Dos Santos, João Otacílio Libardoni

2017-10-01

The purpose of this study was to evaluate electromyography and kinematic parameters of the lower limbs using rebound boots (RB) and barefoot during a gym workout. This information can be helpful to practitioners to schedule rehabilitation and training programs. Ten women (25 ± 9 years) volunteered for the study; inclusion criteria were as follows: subjects must have experienced the use of RB and the analyzed exercises for at least 6 months, and have no previous injuries in the lower limbs. Seven exercises were performed for 30 s with the RB and subsequently barefoot. Data from muscle activation of vastus lateralis (VL), biceps femoris (BF), lateral gastrocnemius (LG) and 2D kinematics were collected. The use of RB triggered postural changes, characterized by greater hip extension (in 4 of the exercises) and knee extension (in 6 of the exercises) for the landing. RB reduced activation mainly in LG (in 6 of the exercise) while no changes were observed for VL (except in exercise 1) and BF. RB change kinematics and muscle activation suggesting changes in the way the legs absorb and transmit force during jumps. LG was the main muscle affected by the use of RB. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cavitation structures formed during the rebound of a sphere from a wetted surface

KAUST Repository

Marston, Jeremy

2010-09-28

We use high-speed imaging to observe the dynamics of cavitation, caused by the impact and subsequent rebound of a sphere from a solid surface covered with a thin layer of highly viscous liquid. We note marked qualitative differences between the cavitation structures with increase in viscosity, as well as between Newtonian and non-Newtonian liquids. The patterns observed are quite unexpected and intricate, appearing in concentric ring formations around the site of impact. In all cases, we identify a distinct radius from which the primary bubbles emanate. This radius is modelled with a modified form of Hertz contact theory. Within this radius, we show that some fine cavitation structure may exist or that it may be one large cavitation bubble. For the non-Newtonian fluids, we observe foam-like structures extending radially with diminishing bubble sizes with increase in radial position. Whereas for the Newtonian fluids, the opposite trend is observed with increasing bubble size for increasing radial position. Finally, we compare our experimental observations of cavitation to the maximum tension criterion proposed by Joseph (J Fluid Mech 366:367-378, 1998) showing that this provides the lower limit for the onset of cavitation in our experiments. © 2010 Springer-Verlag.

Hydrodynamics of multi-sized particles in stable regime of a swirling bed

Energy Technology Data Exchange (ETDEWEB)

Miin, Chin Swee; Sulaiman, Shaharin Anwar; Raghavan, Vijay Raj; Heikal, Morgan Raymond; Naz, Muhammad Yasin [Universiti Teknologi PETRONAS, Perak (Malaysia)

2015-11-15

Using particle imaging velocimetry (PIV), we observed particle motion within the stable operating regime of a swirling fluidized bed with an annular blade distributor. This paper presents velocity profiles of particle flow in an effort to determine effects from blade angle, particle size and shape and bed weight on characteristics of a swirling fluidized bed. Generally, particle velocity increased with airflow rate and shallow bed height, but decreased with bed weight. A 3 .deg. increase in blade angle reduced particle velocity by approximately 18%. In addition, particle shape, size and bed weight affected various characteristics of the swirling regime. Swirling began soon after incipience in the form of a supra-linear curve, which is the characteristic of a swirling regime. The relationship between particle and gas velocities enabled us to predict heat and mass transfer rates between gas and particles.

Study on Characteristics of Constricted DC Plasma Using Particle-In-Cell Simulator

International Nuclear Information System (INIS)

Jo, Jong Gap; Park, Yeong Shin; Hwang, Yong Seok

2010-01-01

In dc glow discharge, when anode size is smaller than cathode, very small and bright plasma ball occurs in front of anode. This plasma is called constricted dc plasma and characterized by a high plasma density in positive glow, so called plasma ball, compared to the conventional dc plasma. For the reason, this plasma is utilized to ion or electron beam sources since the beam currents are enhanced by the dense anode glow. However, correlations between characteristics of the plasma (plasma density, electron temperature and space potential) and discharge conditions (anode size, discharge voltage, discharge current, pressure) have been a little investigated definitely clear in previous study because of the trouble of a diagnosis. The plasma ball which is the most essential part of the constricted plasma is too small to diagnose precisely without disturbing plasma. Therefore, we tried to analyze the constricted plasma through computer simulation with Particle-In-Cell (PIC) code. In this study, simulation result of constricted dc plasma as well as conventional dc glow discharge will be addressed and compared with each others

Clustering and cellular distribution characteristics of virus particles of Tomato spotted wilt virus and Tomato zonate spot virus in different plant hosts.

Science.gov (United States)

Zhang, Zhongkai; Zheng, Kuanyu; Dong, Jiahong; Fang, Qi; Hong, Jian; Wang, Xifeng

2016-01-19

Tomato spotted wilt virus (TSWV) and Tomato zonate spot virus (TZSV) are the two dominant species of thrip-transmitted tospoviruses, cause significant losses in crop yield in Yunnan and its neighboring provinces in China. TSWV and TZSV belong to different serogroup of tospoviruses but induce similar symptoms in the same host plant species, which makes diagnostic difficult. We used different electron microscopy preparing methods to investigate clustering and cellular distribution of TSWV and TZSV in the host plant species. Negative staining of samples infected with TSWV and TZSV revealed that particles usually clustered in the vesicles, including single particle (SP), double particles clustering (DPC), triple particles clustering (TPC). In the immunogold labeling negative staining against proteins of TZSV, the antibodies against Gn protein were stained more strongly than the N protein. Ultrathin section and high pressure freeze (HPF)-electron microscopy preparations revealed that TSWV particles were distributed in the cisternae of endoplasmic reticulum (ER), filamentous inclusions (FI) and Golgi bodies in the mesophyll cells. The TSWV particles clustered as multiple particles clustering (MPC) and distributed in globular viroplasm or cisternae of ER in the top leaf cell. TZSV particles were distributed more abundantly in the swollen membrane of ER in the mesophyll cell than those in the phloem parenchyma cells and were not observed in the top leaf cell. However, TZSV virions were mainly present as single particle in the cytoplasm, with few clustering as MPC. In this study, we identified TSWV and TZSV particles had the distinct cellular distribution patterns in the cytoplasm from different tissues and host plants. This is the first report of specific clustering characteristics of tospoviruses particles as well as the cellular distribution of TSWV particles in the FI and globular viroplasm where as TZSV particles inside the membrane of ER. These results indicated that

Channelling and electromagnetic radiation of channelling particles

International Nuclear Information System (INIS)

Kalashnikov, N.

1983-01-01

A brief description is presented of the channelling of charged particles between atoms in the crystal lattice. The specificities are discussed of the transverse motion of channelling particles as are the origin and properties of quasi-characteristic radiation of channelling particles which accompany transfers from one band of permissible energies of the transverse motion of channelling particles to the other. (B.S.)

Computational Modelling of Gas-Particle Flows with Different Particle Morphology in the Human Nasal Cavity

Directory of Open Access Journals (Sweden)

Kiao Inthavong

2009-01-01

Full Text Available This paper summarises current studies related to numerical gas-particle flows in the human nasal cavity. Of interest are the numerical modelling requirements to consider the effects of particle morphology for a variety of particle shapes and sizes such as very small particles sizes (nanoparticles, elongated shapes (asbestos fibres, rough shapes (pollen, and porous light density particles (drug particles are considered. It was shown that important physical phenomena needed to be addressed for different particle characteristics. This included the Brownian diffusion for submicron particles. Computational results for the nasal capture efficiency for nano-particles and various breathing rates in the laminar regime were found to correlate well with the ratio of particle diffusivity to the breathing rate. For micron particles, particle inertia is the most significant property and the need to use sufficient drag laws is important. Drag correlations for fibrous and rough surfaced particles were investigated to enable particle tracking. Based on the simulated results, semi-empirical correlations for particle deposition were fitted in terms of Peclet number and inertial parameter for nanoparticles and micron particles respectively.

Low fingertip temperature rebound measured by digital thermal monitoring strongly correlates with the presence and extent of coronary artery disease diagnosed by 64-slice multi-detector computed tomography.

Science.gov (United States)

Ahmadi, Naser; Nabavi, Vahid; Nuguri, Vivek; Hajsadeghi, Fereshteh; Flores, Ferdinand; Akhtar, Mohammad; Kleis, Stanley; Hecht, Harvey; Naghavi, Morteza; Budoff, Matthew

2009-10-01

Previous studies showed strong correlations between low fingertip temperature rebound measured by digital thermal monitoring (DTM) during a 5 min arm-cuff induced reactive hyperemia and both the Framingham Risk Score (FRS), and coronary artery calcification (CAC) in asymptomatic populations. This study evaluates the correlation between DTM and coronary artery disease (CAD) measured by CT angiography (CTA) in symptomatic patients. It also investigates the correlation between CTA and a new index of neurovascular reactivity measured by DTM. 129 patients, age 63 +/- 9 years, 68% male, underwent DTM, CAC and CTA. Adjusted DTM indices in the occluded arm were calculated: temperature rebound: aTR and area under the temperature curve aTMP-AUC. DTM neurovascular reactivity (NVR) index was measured based on increased fingertip temperature in the non-occluded arm. Obstructive CAD was defined as >or=50% luminal stenosis, and normal as no stenosis and CAC = 0. Baseline fingertip temperature was not different across the groups. However, all DTM indices of vascular and neurovascular reactivity significantly decreased from normal to non-obstructive to obstructive CAD [(aTR 1.77 +/- 1.18 to 1.24 +/- 1.14 to 0.94 +/- 0.92) (P = 0.009), (aTMP-AUC: 355.6 +/- 242.4 to 277.4 +/- 182.4 to 184.4 +/- 171.2) (P = 0.001), (NVR: 161.5 +/- 147.4 to 77.6 +/- 88.2 to 48.8 +/- 63.8) (P = 0.015)]. After adjusting for risk factors, the odds ratio for obstructive CAD compared to normal in the lowest versus two upper tertiles of FRS, aTR, aTMP-AUC, and NVR were 2.41 (1.02-5.93), P = 0.05, 8.67 (2.6-9.4), P = 0.001, 11.62 (5.1-28.7), P = 0.001, and 3.58 (1.09-11.69), P = 0.01, respectively. DTM indices and FRS combined resulted in a ROC curve area of 0.88 for the prediction of obstructive CAD. In patients suspected of CAD, low fingertip temperature rebound measured by DTM significantly predicted CTA-diagnosed obstructive disease.

Volatile release and particle formation characteristics of injected pulverized coal in blast furnaces

International Nuclear Information System (INIS)

Chen, Wei-Hsin; Du, Shan-Wen; Yang, Tsung-Han

2007-01-01

Volatiles release and particle formation for two kinds of pulverized coals (a high volatile bituminous coal and a low volatile bituminous coal) in a drop tube furnace are investigated to account for the reactions of pulverized coal injected in blast furnaces. Two different sizes of feed particles are considered; one is 100-200 mesh and the other is 200-325 mesh. By evaluating the R-factor, the devolatilization extent of the larger feed particles is found to be relatively poor. However, the swelling behavior of individual or two agglomerated particles is pronounced, which is conducive to gasification of the chars in blast furnaces. In contrast, for the smaller feed particles, volatiles liberated from the coal particles can be improved in a significant way as a result of the amplified R-factor. This enhancement can facilitate the performance of gas phase combustion. Nevertheless, the residual char particles are characterized by agglomeration, implying that the reaction time of the char particles will be lengthened, thereby increasing the possibility of furnace instability. Double peak distributions in char particle size are observed in some cases. This possibly results from the interaction of the plastic state and the blowing effect at the particle surface. Considering the generation of tiny aerosols composed of soot particles and tar droplets, the results indicate that their production is highly sensitive to the volatile matter and elemental oxygen contained in the coal. Comparing the reactivity of the soot to that of the unburned char, the former is always lower than the latter. Consequently, the lower is the soot formation, the better is the blast furnace stability

Energy characteristics of finest coal particles surfaces versus their upgrading using flotation

Energy Technology Data Exchange (ETDEWEB)

Jerzy Sablik

2007-07-01

The paper presents selected results of investigations on energy properties of the fine coal particles, and methodological grounds for conducting such investigations. Using the discussed relationships, values of contact angle of coal particles with various degree of coalification in the range defined by the energy nonhomogeneity of the surfaces were computed. There have been determined the values of the contact angles of coal particles with hydrophobic and hydrophilic surfaces after coating with nonpolar and polar reagents. The energy state of the surfaces of coal particles in the feeds and products of industrial flotation were determined, which enabled to evaluate this process. 22 refs., 6 figs., 4 tabs.

Comparison of Single-Particle Monte Carlo Simulation with Measured Output Characteristics of an 0.1µm n-MOSFET

Directory of Open Access Journals (Sweden)

F. M. Bufler

2002-01-01

Full Text Available A comparison between non-selfconsistent single-particle Monte Carlo (MC simulations and measurements of the output characteristics of an 0.1 µm n-MOSFET is presented. First the bulk MC model, which features a new simplified treatment of inelastic acoustic intravalley scattering, is validated by comparison with experimental literature data for mobilities and velocities. The dopant distribution of the MOSFET is obtained from a 2D process simulation, which is calibrated with SIMS and electrical measurements and fine-tuned by a comparison of the measured transfer characteristics in the subthreshold regime with a coupled Schro¨dinger drift-diffusion (DD simulation. Then the quantum effect is replaced by a shift of the work function and the DD, hydrodynamic (HD and MC models are adjusted to reproduce the measured drain current in the linear regime. The results of the three models in the non-linear regime are compared without further adjustment to the measured output characteristics. While good agreement is found for the MC model, the on-current is significantly overestimated by the HD model and underestimated by the DD model.

[Emission characteristics of fine particles from grate firing boilers].

Science.gov (United States)

Wang, Shu-Xiao; Zhao, Xiu-Juan; Li, Xing-Hua; Wei, Wei; Hao, Ji-Ming

2009-04-15

Grate firing boilers are the main type of Chinese industrial boilers, which accounts for 85% of the industrial boilers and is one of the most important emission sources of primary air pollutants in China. In this study, five boilers in three cities were selected and tested to measure the emission characteristics of PM2.5, and gaseous pollutants were applied by a compact dilution sampling system, which was developed for this field study. Results showed that particles mass size distributions for the five industrial boilers presented single peak or double peak, former peaks near 0.14 microm and the later peaks after 1.0 microm; the cyclone dust remover and wet scrubber dust remover had effective removal efficiencies not only to PM2.5, but also to PM1.0; and under the condition of same control techniques, grate firing boiler with high capacity has less PM2.5 emission than the boiler with low capacity. In the PM2.5 collected from flue gases, SO4(2-) was the most abundant ion, accounted for 20%-40% of the PM2.5; and C was the most abundant element (7.5%-31.8%), followed by S (8.4%-18.7%). Carbon balance method was applied to calculate the emission factors of these pollutants. The emission factors of PM2.5, NO, and SO2 were in the range of 0.046-0.486 g x kg(-1), 1.63-2.47 g x kg(-1), 1.35-9.95 g x kg(-1) respectively. The results are useful for the emission inventory development of industrial boilers and the source analysis of PM2.5 in atmospheric environment.

Charged particle beam monitoring by means of synchrotron radiation

International Nuclear Information System (INIS)

Panasyuk, V.S.; Anevskij, S.I.

1984-01-01

Optical methods for monitoring the number of accelerated electrons and electron energy by means of beam synchrotron radiation (SR) as well as peculiarities of SR characteristics of beams with a small radius of the orbit are considered. Optical methods for charged particle beam monitoring are shown to ensure operative and precise monitoring the number of particles and particle energy. SR sources with large axial dimensions of an electron beam have specific spectral angular and polarization characteristics. If electron angular distribution at deflection from the median plane is noticeably wider than angular distribution of SR of a certain electron, relative SR characteristics of these soUrces are calculated with high accuracy

Properties of supersymmetric particles and processes

International Nuclear Information System (INIS)

Barnett, R.M.

1986-01-01

The motivations for experimental searches for supersymmetric particles are discussed. The role of R-parity in these searches is described. The production and decay characteristics of each class of supersymmetric particles are investigated in the context of both e+e- and hadron machines. There is a detailed presentation of a sample calculation of a supersymmetric process. Emphasis is given to the signatures for detection of supersymmetric particles and processes. The current limits for supersymmetric particles are given. 125 refs., 50 figs

Termination of dobutamine infusion causes transient rebound left heart diastolic dysfunction in healthy elderly women but not in men

DEFF Research Database (Denmark)

Ahtarovski, Kiril A; Iversen, Kasper K; Lønborg, Jacob T

2013-01-01

Men and women are known to react differently to stress. Thus, stress cardiomyopathy almost solely strikes women. Stress cardiomyopathy is suggested to relate to sex differences in catecholamine reaction. Left heart function during dobutamine stress is well described, but sex-specific inotropic...... and lusitropic response to abrupt termination of dobutamine stress is not. We aimed to investigate sex differences in left ventricular (LV) and atrial (LA) function during and after dobutamine stress. We enrolled 20 healthy elderly subjects (60-70 yr, 10 females) and measured their LV and LA volumes throughout......, and conduit volumes. Sex differences were not observed at rest or during dobutamine stress. Compared with prestress values, at T15 a rebound decrease in LV peak filling rate was observed in women (-22 ± 3%, P...

Irradiation behaviors of coated fuel particles, (4)

International Nuclear Information System (INIS)

Fukuda, Kousaku; Kashimura, Satoru; Ogawa, Toru; Ikawa, Katsuichi; Iwamoto, Kazumi; Ishimoto, Kiyoshi

1981-09-01

Loose coated fuel particles prepared in confirmity to a preliminary design for the multi-purpose VHTR in fiscal 1972 - 1974 were irradiated by 73F - 12A capsule in JMTR. Main purpose for this irradiation experiment was to examine irradiation stability of the candidate TRISO coated fuel particles for the VHTR. Also the coated particles possessing low-density kernel (90%TD), highly anisotropic OLTI-PyC and ZrC coating layer were loaded with the candidate particles in this capsule. The coated particles were irradiated up to 1.5 x 10 21 n/cm 2 of fast neutron fluence (E > 0.18 MeV) and 3.2% FIMA of burnup. In the post irradiation examination it was observed that among three kinds of TRISO particles exposed to irradiation corresponding to the normal operating condition of the VHTR ones possessing poor characteristics of the coating layers did not show a good stability. The particles irradiated under abnormally high temperature condition (> 1800 0 C) revealed 6.7% of max. EOL failure fraction (95% confidence limit). Most of these particles were failed by the ameoba effect. Furthermore, among four kinds of the TRISO particles exposed to irradiation corresponding to the transient condition of the VHTR (--1500 0 C) the two showed a good stability, while the particles possessing highly anisotropic OLTI-PyC or poorly characteristic coating layers were not so good. (author)

Solar flares, coronal mass ejections and solar energetic particle event characteristics

Science.gov (United States)

Papaioannou, Athanasios; Sandberg, Ingmar; Anastasiadis, Anastasios; Kouloumvakos, Athanasios; Georgoulis, Manolis K.; Tziotziou, Kostas; Tsiropoula, Georgia; Jiggens, Piers; Hilgers, Alain

2016-12-01

A new catalogue of 314 solar energetic particle (SEP) events extending over a large time span from 1984 to 2013 has been compiled. The properties as well as the associations of these SEP events with their parent solar sources have been thoroughly examined. The properties of the events include the proton peak integral flux and the fluence for energies above 10, 30, 60 and 100 MeV. The associated solar events were parametrized by solar flare (SF) and coronal mass ejection (CME) characteristics, as well as related radio emissions. In particular, for SFs: the soft X-ray (SXR) peak flux, the SXR fluence, the heliographic location, the rise time and the duration were exploited; for CMEs the plane-of-sky velocity as well as the angular width were utilized. For radio emissions, type III, II and IV radio bursts were identified. Furthermore, we utilized element abundances of Fe and O. We found evidence that most of the SEP events in our catalogue do not conform to a simple two-class paradigm, with the 73% of them exhibiting both type III and type II radio bursts, and that a continuum of event properties is present. Although, the so-called hybrid or mixed events are found to be present in our catalogue, it was not possible to attribute each SEP event to a mixed/hybrid sub-category. Moreover, it appears that the start of the type III burst most often precedes the maximum of the SF and thus falls within the impulsive phase of the associated SF. At the same time, type III bursts take place within ≈5.22 min, on average, in advance from the time of maximum of the derivative of the SXR flux (Neupert effect). We further performed a statistical analysis and a mapping of the logarithm of the proton peak flux at E > 10 MeV, on different pairs of the parent solar source characteristics. This revealed correlations in 3-D space and demonstrated that the gradual SEP events that stem from the central part of the visible solar disk constitute a significant radiation risk. The velocity of

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

Science.gov (United States)

Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel; Amorim Holanda, Bruna; Artaxo, Paulo; Barbosa, Henrique M. J.; Borrmann, Stephan; Cecchini, Micael A.; Costa, Anja; Dollner, Maximilian; Fütterer, Daniel; Järvinen, Emma; Jurkat, Tina; Klimach, Thomas; Konemann, Tobias; Knote, Christoph; Krämer, Martina; Krisna, Trismono; Machado, Luiz A. T.; Mertes, Stephan; Minikin, Andreas; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Sauer, Daniel; Schlager, Hans; Schnaiter, Martin; Schneider, Johannes; Schulz, Christiane; Spanu, Antonio; Sperling, Vinicius B.; Voigt, Christiane; Walser, Adrian; Wang, Jian; Weinzierl, Bernadett; Wendisch, Manfred; Ziereis, Helmut

2018-01-01

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September-October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles ( 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable

Rebound - Effects on the use of energy and environment by improvements in effectiveness; Effekter av effektivisering paa energibruk og miljoe

Energy Technology Data Exchange (ETDEWEB)

Grepperud, Sverre; Rasmussen, Ingeborg

1998-07-01

The purpose of this report is to evaluate possible long run effects on use of energy and CO2-emissions from improved energy efficiency in various production sectors and for some consumption goods. The results suggest that improved energy efficiency decrease energy consumption, but the initial reduction is modified over time due to Rebound effects which arises from changes in income and prices. Wide differences in changed energy use are observed across the sectors evaluated. The report also include an analysis of possible effects from installing new environmental technology or clean up technology at firm level. The consequences of such new technologies are found to depend on the type of technology implemented, but also on the type of environmental regulation a firm is subjected to. (author)

Effect of Impact Angle on Ceramic Deposition Behavior in Composite Cold Spray: A Finite-Element Study

Science.gov (United States)

Chakrabarty, Rohan; Song, Jun

2017-10-01

During the cold spraying of particle-reinforced metal matrix composite coatings (ceramic and metal particles mixture) on metal substrates, ceramic particles may either get embedded in the substrate/deposited coating or may rebound from the substrate surface. In this study, the dependence of the ceramic rebounding phenomenon on the spray angle and its effect on substrate erosion have been analyzed using finite-element analysis. From the numerical simulations, it was found that the ceramic particle density and substrate material strength played the major roles in determining the embedding and ceramic retention behavior. Substrate material erosion also influenced the ceramic retention, and the material loss increased as the impact angles decreased from normal. In general, the results concluded that decreasing the impact angle promoted the retention possibility of ceramics in the substrate. This study provides new theoretical insights into the effect of spray angles on the ceramic retention and suggests a new route toward optimizing the spraying process to increase the ceramic retention in composite coatings cold spray.

Relationship Between Particle and Plasma Properties and Coating Characteristics of Samaria-Doped Ceria Prepared by Atmospheric Plasma Spraying for Use in Solid Oxide Fuel Cells

Science.gov (United States)

Cuglietta, Mark; Kesler, Olivera

2012-06-01

Samaria-doped ceria (SDC) has become a promising material for the fabrication of high-performance, intermediate-temperature solid oxide fuel cells (SOFCs). In this study, the in-flight characteristics, such as particle velocity and surface temperature, of spray-dried SDC agglomerates were measured and correlated to the resulting microstructures of SDC coatings fabricated using atmospheric plasma spraying, a manufacturing technique with the capability of producing full cells in minutes. Plasmas containing argon, nitrogen and hydrogen led to particle surface temperatures higher than those in plasmas containing only argon and nitrogen. A threshold temperature for the successful deposition of SDC on porous stainless steel substrates was calculated to be 2570 °C. Coating porosity was found to be linked to average particle temperature, suggesting that plasma conditions leading to lower particle temperatures may be most suitable for fabricating porous SOFC electrode layers.

Aerodynamic properties of six organo-mineral fertiliser particles

Directory of Open Access Journals (Sweden)

Marcello Biocca

2013-09-01

Full Text Available Agricultural fertilisers are generally applied by means of centrifugal disk spreaders. The machinery, the working conditions and the physical characteristics of fertilizers (including the aerodynamic characteristics of particles may affect the behaviour of particles after the discarding from the spreader. We investigated the aerodynamic properties of organo-mineral fertilisers (a class of slow release fertilisers that are less investigated since they are relatively new in the market using a vertical wind tunnel similar to an elutriator. In the same time, the morphological characteristics of individual fertilizer particles were measured by means of an image analysis procedure. In the study we compare six different fertilisers and we discuss the suitability of the employed methods. The results provide the terminal velocity – Vt – (the velocity value that overcome the gravity force of the particles of the particles, ranging from 8.60 to 9.55 m s-1, and the relationships between Vt and some physical properties (mass, shape, dimensions of the fertilizers. Moreover, the results of field distribution trials show the behaviour of the tested fertilizers during practical use. Such data can contribute to enhance the quality of application of these products in field.

Stay the Course or Seize an Opportunity? Options for Alberta’s Post-Secondary Institutions in a Period of Uncertainty About the Rebound of the Oil Economy

Directory of Open Access Journals (Sweden)

Ken Norrie

2017-09-01

Full Text Available Colleges and universities in Alberta feel the booms and busts of the oil-driven economy, too. When oil prices are high, and oil exploration and new project construction are booming, post-secondary institutions will often find themselves unable to keep up with the demand for the education and skills-training programs that employers are clamouring for, with fewer spots available for students than there are students eager to fill them. When oil prices drop, and exploration and construction dry up, the schools face the opposite problem: They have too much capacity in the kinds of programs for skills that traditionally serve those sectors directly connected to oil, or closely linked to them, where there is suddenly a glut of available labour. Making matters particularly complicated is that when oil prices fall, there is never any certainty of when they will rebound. If the lower oil prices are short lived like after 2009, colleges and universities have needed only to be patient and ride out shortterm disruptions, without the need to restructure their program offerings. However, that was not the case after 1985, where oil prices stagnated for an extended period of time. Now, some observers project that the decline in oil prices that began in 2014, with prices yet to fully recover, could last even longer, perhaps with oil becoming the “new coal” and remaining in glut indefinitely. Not knowing whether oil prices will rebound sooner, later, or never puts Alberta’s post-secondary institutions in a tricky situation. Their programs providing skilled workers to the province’s oil-based economy are longstanding and well-respected and the prospect of shrinking them or dismantling them, and shifting a school’s focus to different programming priorities, should not be taken lightly as it could be very expensive to reverse if oil prices do indeed end up rebounding. But if they do not, they will nevertheless face pressure to do so, anyway, due to the

Challenges associated with the behaviour of radioactive particles in the environment.

Science.gov (United States)

Salbu, Brit; Kashparov, Valery; Lind, Ole Christian; Garcia-Tenorio, Rafael; Johansen, Mathew P; Child, David P; Roos, Per; Sancho, Carlos

2018-06-01

A series of different nuclear sources associated with the nuclear weapon and fuel cycles have contributed to the release of radioactive particles to the environment. Following nuclear weapon tests, safety tests, conventional destruction of weapons, reactor explosions and fires, a major fraction of released refractory radionuclides such as uranium (U) and plutonium (Pu) were present as entities ranging from sub microns to fragments. Furthermore, radioactive particles and colloids have been released from reprocessing facilities and civil reactors, from radioactive waste dumped at sea, and from NORM sites. Thus, whenever refractory radionuclides are released to the environment following nuclear events, radioactive particles should be expected. Results from many years of research have shown that particle characteristics such as elemental composition depend on the source, while characteristics such as particle size distribution, structure, and oxidation state influencing ecosystem transfer depend also on the release scenarios. When radioactive particles are deposited in the environment, weathering processes occur and associated radionuclides are subsequently mobilized, changing the apparent K d . Thus, particles retained in soils or sediments are unevenly distributed, and dissolution of radionuclides from particles may be partial. For areas affected by particle contamination, the inventories can therefore be underestimated, and impact and risk assessments may suffer from unacceptable large uncertainties if radioactive particles are ignored. To integrate radioactive particles into environmental impact assessments, key challenges include the linking of particle characteristics to specific sources, to ecosystem transfer, and to uptake and retention in biological systems. To elucidate these issues, the EC-funded COMET and RATE projects and the IAEA Coordinated Research Program on particles have revisited selected contaminated sites and archive samples. This COMET position

Numerical Study of Particle Interaction in Gas-Particle and Liquid-Particle Flows: Part II Particle Response

Directory of Open Access Journals (Sweden)

K. Mohanarangam

2009-09-01

Full Text Available In this paper the numerical model, which was presented in the first paper (Mohanarangam & Tu; 2009 of this series of study, is employed to study the different particle responses under the influence of two carrier phases namely the gas and the liquid. The numerical model takes into consideration the turbulent behaviour of both the carrier and the dispersed phases, with additional equations to take into account the combined fluid particle behaviour, thereby effecting a two-way coupling. The first paper in this series showed the distinct difference in particulate response both at the mean as well as at the turbulent level for two varied carrier phases. In this paper further investigation has been carried out over a broad range of particle Stokes number to further understand their behaviour in turbulent environments. In order to carry out this prognostic study, the backward facing step geometry of Fessler and Eaton (1999 has been adopted, while the inlet conditions for the carrier as well as the particle phases correspond to that of the experiments of Founti and Klipfel (1998. It is observed that at the mean velocity level the particulate velocities increased with a subsequent increase in the Stokes number for both the GP (Gas-Particle as well as the LP (Liquid-Particle flow. It was also observed that across the Stokes number there was a steady increase in the particulate turbulence for the GP flows with successive increase in Stokes number. However, for the LP flows, the magnitude of the increase in the particulate turbulence across the increasing of Stokes number is not as characteristic as the GP flow. Across the same sections for LP flows the majority of the trend shows a decrease after which they remain more or less a constant.

The crystallization processes in the aluminum particles production technology

Directory of Open Access Journals (Sweden)

Arkhipov Vladimir

2015-01-01

Full Text Available The physical and mathematical model of the crystallization process of liquid aluminum particles in the spray-jet of the ejection-type atomizer was proposed. The results of mathematical modeling of two-phase flow in the spray-jet and the crystallization process of fluid particles are given. The influence of the particle size, of the flow rate and the stagnation temperature gas in the ranges of industrial technology implemented for the production of powders aluminum of brands ASD, on the crystallization characteristics were investigated. The approximations of the characteristics of the crystallization process depending on the size of the aluminum particles on the basis of two approaches to the mathematical description of the process of crystallization of aluminum particles were obtained. The results allow to optimize the process parameters of ejection-type atomizer to produce aluminum particles with given morphology.

PART 2: LARGE PARTICLE MODELLING Simulation of particle filtration processes in deformable media

Directory of Open Access Journals (Sweden)

Gernot Boiger

2008-06-01

Full Text Available In filtration processes it is necessary to consider both, the interaction of thefluid with the solid parts as well as the effect of particles carried in the fluidand accumulated on the solid. While part 1 of this paper deals with themodelling of fluid structure interaction effects, the accumulation of dirtparticles will be addressed in this paper. A closer look is taken on theimplementation of a spherical, LAGRANGIAN particle model suitable forsmall and large particles. As dirt accumulates in the fluid stream, it interactswith the surrounding filter fibre structure and over time causes modificationsof the filter characteristics. The calculation of particle force interactioneffects is necessary for an adequate simulation of this situation. A detailedDiscrete Phase Lagrange Model was developed to take into account thetwo-way coupling of the fluid and accumulated particles. The simulation oflarge particles and the fluid-structure interaction is realised in a single finitevolume flow solver on the basis of the OpenSource software OpenFoam.

Characteristics of Nano Particles in the Atmosphere of Gyeongju National Park Area Using a Proton Accelerator

International Nuclear Information System (INIS)

Kim, K. W.; Hur, H. J.; Choi, J. H.; Kim, H. S.

2007-04-01

The physico-chemical characteristics of the categorized aerosol with soil-related mineral species, anthropogenic-related heavy metal species, and aerosol-acidity-related element were analyzed based on the air-mass pathways. The lowest value of 0.6 ± 0.1 g m-3 was observed during the intensive fall period of 2005. The mass concentration of sulfur (S) was the highest in the intensive spring period and the lowest in the intensive summer period. The frequencies of the EM, the WC, the SC, and the NC events were 6, 17, 3, and 7, respectively. The continental air-mass-pathway categories were calculated consisting of 85% of the total 40 events whereas the marine air-mass-pathway categories were of 15%. The nanoparticles observed at the national park area of Gyeongju were estimated to be affected by soil-related elements when the air mass came from the western area of the Asian continent and to be predominantly affected by anthropogenic-related elements when air mass came from the northern area of the Asian continent through Korean peninsula. Soil-related elements were mainly observed in particles with sizes greater than 560 nm. The average mass fraction of anthropogenic-related elements was relatively much higher in the particle size range less than 320 nm

Characteristics of Nano Particles in the Atmosphere of Gyeongju National Park Area Using a Proton Accelerator

Energy Technology Data Exchange (ETDEWEB)

Kim, K. W.; Hur, H. J.; Choi, J. H.; Kim, H. S. [Gyeongju Univ., Gyeongju (Korea, Republic of)

2007-04-15

The physico-chemical characteristics of the categorized aerosol with soil-related mineral species, anthropogenic-related heavy metal species, and aerosol-acidity-related element were analyzed based on the air-mass pathways. The lowest value of 0.6 {+-} 0.1 g m-3 was observed during the intensive fall period of 2005. The mass concentration of sulfur (S) was the highest in the intensive spring period and the lowest in the intensive summer period. The frequencies of the EM, the WC, the SC, and the NC events were 6, 17, 3, and 7, respectively. The continental air-mass-pathway categories were calculated consisting of 85% of the total 40 events whereas the marine air-mass-pathway categories were of 15%. The nanoparticles observed at the national park area of Gyeongju were estimated to be affected by soil-related elements when the air mass came from the western area of the Asian continent and to be predominantly affected by anthropogenic-related elements when air mass came from the northern area of the Asian continent through Korean peninsula. Soil-related elements were mainly observed in particles with sizes greater than 560 nm. The average mass fraction of anthropogenic-related elements was relatively much higher in the particle size range less than 320 nm.

Particles and forces

International Nuclear Information System (INIS)

Peierls, R.

1981-01-01

The particles and forces of matter, found in the Universe, are discussed with especial reference to some of the laws which govern behaviour in the sub-atomic world and which determine the way forces work to give matter its various characteristics. The recent history of the search for elementary constituents of matter in this century is outlined and the replacement of the simplicity anticipated in the 1930s by the proliferation of particle states uncovered in the 1950s and 1960s which led to the quark model is examined. (U.K.)

Particle detectors

CERN Document Server

Hilke, Hans Jürgen; Joram, Christian; CERN. Geneva

1991-01-01

Lecture 5: Detector characteristics: ALEPH Experiment cut through the devices and events - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operartion and a few ideas on the future performance. Lecture 4-pt. b Following the Scintillators. Lecture 4-pt. a : Scintillators - Used for: -Timing (TOF, Trigger) - Energy Measurement (Calorimeters) - Tracking (Fibres) Basic scintillation processes- Inorganic Scintillators - Organic Scintil - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operation and a fiew ideas on future developpement session 3 - part. b Following Calorimeters lecture 3-pt. a Calorimeters - determine energy E by total absorption of charged or neutral particles - fraction of E is transformed into measurable quantities - try to acheive sig...

Online single particle analysis of ice particle residuals from mountain-top mixed-phase clouds using laboratory derived particle type assignment

Science.gov (United States)

Schmidt, Susan; Schneider, Johannes; Klimach, Thomas; Mertes, Stephan; Schenk, Ludwig Paul; Kupiszewski, Piotr; Curtius, Joachim; Borrmann, Stephan

2017-01-01

In situ single particle analysis of ice particle residuals (IPRs) and out-of-cloud aerosol particles was conducted by means of laser ablation mass spectrometry during the intensive INUIT-JFJ/CLACE campaign at the high alpine research station Jungfraujoch (3580 m a.s.l.) in January-February 2013. During the 4-week campaign more than 70 000 out-of-cloud aerosol particles and 595 IPRs were analyzed covering a particle size diameter range from 100 nm to 3 µm. The IPRs were sampled during 273 h while the station was covered by mixed-phase clouds at ambient temperatures between -27 and -6 °C. The identification of particle types is based on laboratory studies of different types of biological, mineral and anthropogenic aerosol particles. The outcome of these laboratory studies was characteristic marker peaks for each investigated particle type. These marker peaks were applied to the field data. In the sampled IPRs we identified a larger number fraction of primary aerosol particles, like soil dust (13 ± 5 %) and minerals (11 ± 5 %), in comparison to out-of-cloud aerosol particles (2.4 ± 0.4 and 0.4 ± 0.1 %, respectively). Additionally, anthropogenic aerosol particles, such as particles from industrial emissions and lead-containing particles, were found to be more abundant in the IPRs than in the out-of-cloud aerosol. In the out-of-cloud aerosol we identified a large fraction of aged particles (31 ± 5 %), including organic material and secondary inorganics, whereas this particle type was much less abundant (2.7 ± 1.3 %) in the IPRs. In a selected subset of the data where a direct comparison between out-of-cloud aerosol particles and IPRs in air masses with similar origin was possible, a pronounced enhancement of biological particles was found in the IPRs.

EFFECTS OF EFFECTS OF PARTICLE SIZE DISTRIBUTION ...

African Journals Online (AJOL)

eobe

The parameters examined were: moisture content, particle size distribution, total isture content, particle size distribution, total hydrocarbon content, soil pH, available nitrogen, available phosphorus, total heterotrophic bacteria and fungi count. The analysis of the soil characteristics throughout the remediation period showed ...

Method for calculating the characteristics of nuclear reactions with composite particle

International Nuclear Information System (INIS)

Zelenskaya, N.S.

1978-01-01

The purpose of the lectures is to attempt to give a brief review of the present status of the theory of nuclear reactions involving composite particles (heavy ions, 6 Li, 7 Li, and 9 Be ions, α-particles). In order to analyze such reactions, one should employ and ''exact'' method of distorted waves with a finite radius of interaction. Since the zero radius approximation is valid only at low momentum transfer, its rejection immediately includes all possible transferred momenta and consequently, the reaction mechanisms different from the usual cluster stripping we shall discuss a sufficiently general formalism of the distorted waves method, which does not use additional assumptions about the smaliness of the region of interaction between particles and about the possible reaction mechanisms. We shall also discuss all physical simplifications introduced in specific particular codes and the ranges of their applicability will be established. (author)

Characteristics of fine and coarse particles of natural and urban aerosols of Brazil

International Nuclear Information System (INIS)

Orsini, C.M.Q.; Tabacniks, M.H.; Artaxo Netto, P.E.; Andrade, M.F.; Kerr, A.

1986-02-01

Fine and coarse particles have been sampled from 1982 to 1985 in one natural forest seacoast site (Jureia) and five urban-industrial cities (Vitoria, Salvador, Porto Alegre, Sao Paulo, and Belo Horizonte). The time variations of concentrations in air and the relative elemental compositions of fine and coarse particle fractions, sampled by Nuclepore stacked filter units (SFU), have been determined gravimetrically and by PIXE analysis, respectively. Enrichment factors and correlation coefficients of the trace elements measured lead to unambiguous characterization of soil dust and sea salt, both major aerosol sources that emit coarse particles, and soil dust is also a significant source of fine particles. (Author) [pt

Bound and rebound states

International Nuclear Information System (INIS)

Orzalesi, C.A.

1979-01-01

In relativistic quantum theory, bound states generate forces in the crossed channel; such forces can affect the binding and self-consistent solutions should be sought for the bound-state problem. The author investigates how self-consistency can be achieved by successive approximations, in a simple scalar model and with successive relativistic eikonal approximations (EAs). Within the generalized ladder approximation, some exact properties of the resulting ''first generation'' bound states are discussed. The binding energies in this approximation are rather small even for rather large values of the primary coupling constant. The coupling of the constituent particles to the first-generation reggeon is determined by a suitable EA and a new generalized ladder amplitude is constructed with rungs given either by the primary gluons or by the first-generation reggeons. The resulting new (second-generation) bound states are found in a reggeized EA. The size of the corrections to the binding energies due to the rebinding effects is surprisingly large. The procedure is then iterated, so as to find - again in an EA - the third-generation bound states. The procedure is found to be self-consistent already at this stage: the third-generation bound states coincide with those of second generation, and no further rebinding takes place in the higher iterations of the approximation method. Features - good and bad - of the model are discussed, as well as the possible relevance of rebinding mechanisms in hadron dynamics. (author)

Characteristics of turbulent particle transport in human airways under steady and cyclic flows

International Nuclear Information System (INIS)

Jedelsky, Jan; Lizal, Frantisek; Jicha, Miroslav

2012-01-01

Highlights: ► PDA data allow to estimate PSD of particle velocity fluctuations in realistic model. ► PSD of micron-sized particles is independent of their size up to 700 Hz. ► Such particles follow air flow and turb. diffusion contributes to their deposition. ► Cyclic flow PSDs contain more TKE at high freq. than equivalent steady-flow PSDs. ► Exp. breathing phase differs from insp. phase at high frequency part of the spectra. - Abstract: Motion of monodispersed aerosol particles suspended in air flow has been studied on realistic transparent model of human airways using Phase Doppler Particle Analyser (P/DPA). Time-resolved velocity data for particles in size range 1–8 μm were processed using Fuzzy Slotting Technique to estimate the power spectral density (PSD) of velocity fluctuations. The optimum processing setup for our data was found and recommendations for future experiments to improve PSD quality were suggested. Typical PSD plots at mainstream positions of the trachea and the upper bronchi are documented and differences among (1) steady-flow regimes and equivalent cyclic breathing regimes, (2) inspiration and expiration breathing phase and (3) behaviour of particles of different sizes are described in several positions of the airway model. Systematically higher level of velocity fluctuations in the upper part of the frequency range (30–500 Hz) was found for cyclic flows in comparison with corresponding steady flows. Expiratory flows in both the steady and cyclic cases produce more high-frequency fluctuations compared to inspiratory flows. Negligible differences were found for flow of particles in the inspected size range 1–8 μm at frequencies below 500 Hz. This finding was explained by Stokes number analysis. Implied match of the air and particle flows thereby indicates turbulent diffusion as important deposition mechanism and confirms the capability to use the P/DPA data as the air flow velocity estimate.

Characteristics and settling behaviour of particles from blast furnace flue gas washing.

Science.gov (United States)

Kiventerä, Jenni; Leiviskä, Tiina; Keski-Ruismäki, Kirsi; Tanskanen, Juha

2016-05-01

A lot of particles from iron-making are removed with blast furnace off-gas and routed to the gas cleaning system. As water is used for cleaning the gas, the produced wash water contains a large amount of particles such as valuable Fe and C. However, the presence of zinc prevents recycling. In addition, the high amount of calcium results in uncontrolled scaling. Therefore, the properties of the wash water from scrubber and sludge, from the Finnish metal industry (SSAB Raahe), were evaluated in this study. Size fractionation of wash water revealed that Fe, Zn, Al, Mn, V, Cr and Cd appeared mainly in the larger fractions (>1.2 μm) and Na, Mg, Si, Ni, K, Cu and As appeared mainly in the smaller fractions (<1.2 μm) or in dissolved form. Calcium was found both in the larger fractions and dissolved (∼60 mg/L). Most of the particles in wash water were included in the 1.2-10 μm particle size and were settled effectively. However, a clear benefit was observed when using a chemical to enhance particle settling. In comparison to 2.5 h of settling without chemical, the turbidity was further decreased by about 94%, iron 85% and zinc 50%. Coagulation-flocculation experiments indicated that both low and high molecular weight cationic polymers could provide excellent purification results in terms of turbidity. Calcium should be removed by other methods. The particles in sludge were mostly in the 2-4 μm or 10-20 μm fractions. Further sludge settling resulted in high solids removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Challenges associated with the behaviour of radioactive particles in the environment

DEFF Research Database (Denmark)

Salbu, Brit; Kashparov, Valery; Lind, Ole Christian

2018-01-01

sites. Thus, whenever refractory radionuclides are released to the environment following nuclear events, radioactive particles should be expected. Results from many years of research have shown that particle characteristics such as elemental composition depend on the source, while characteristics...... on advanced techniques, with emphasis on particle weathering processes as well as on heterogeneities in biological samples to evaluate potential uptake and retention of radioactive particles.......A series of different nuclear sources associated with the nuclear weapon and fuel cycles have contributed to the release of radioactive particles to the environment. Following nuclear weapon tests, safety tests, conventional destruction of weapons, reactor explosions and fires, a major fraction...

Dynamics of colloidal particles in ice

KAUST Repository

Spannuth, Melissa

2011-01-01

We use x-ray photon correlation spectroscopy (XPCS) to probe the dynamics of colloidal particles in polycrystalline ice. During freezing, the dendritic ice morphology and rejection of particles from the ice created regions of high particle density, where some of the colloids were forced into contact and formed disordered aggregates. The particles in these high density regions underwent ballistic motion, with a characteristic velocity that increased with temperature. This ballistic motion is coupled with both stretched and compressed exponential decays of the intensity autocorrelation function. We suggest that this behavior could result from ice grain boundary migration. © 2011 American Institute of Physics.

Subsidence and Rebound in California's Central Valley: Effects of Pumping, Geology, and Precipitation

Science.gov (United States)

Farr, T. G.; Fairbanks, A.

2017-12-01

Recent rains in California caused a pause, and even a reversal in some areas, of the subsidence that has plagued the Central Valley for decades. The 3 main drivers of surface deformation in the Central Valley are: Subsurface hydro-geology, precipitation and surface water deliveries, and groundwater pumping. While the geology is relatively fixed in time, water inputs and outputs vary greatly both in time and space. And while subsurface geology and water inputs are reasonably well-known, information about groundwater pumping amounts and rates is virtually non-existent in California. We have derived regional maps of surface deformation in the region for the period 2006 - present which allow reconstruction of seasonal and long-term changes. In order to understand the spatial and temporal patterns of subsidence and rebound in the Central Valley, we have been compiling information on the geology and water inputs and have attempted to infer pumping rates using maps of fallowed fields and published pumping information derived from hydrological models. In addition, the spatial and temporal patterns of hydraulic head as measured in wells across the region allow us to infer the spatial and temporal patterns of groundwater pumping and recharge more directly. A better understanding of how different areas (overlying different stratigraphy) of the Central Valley respond to water inputs and outputs will allow a predictive capability, potentially defining sustainable pumping rates related to water inputs. * work performed under contract to NASA and the CA Dept. of Water Resources

Investigations of the sorption characteristics of radiosilver on some natural and artificial soil particles

Energy Technology Data Exchange (ETDEWEB)

Szabo, Gyula; Guczi, Judit [`FJC` National Research Institute for Radiobiology and Radiohygiene, Budapest (Hungary); Valyon, Jozef [Central Research Institute for Chemistry, Hungarian Academy of Sciences, Budapest (Hungary); Bulman, Robert A. [National Radiological Protection Board, Chilton Didcot, England (United Kingdom)

1995-09-05

The likely distribution of {sup 110m}Ag(I), a radionuclide that may be produced in nuclear power stations and which has been known to contaminate the environment, between the components of particles of soil has been investigated by measuring its uptake from solutions of sodium nitrate, sodium EDTA and sodium citrate onto particles of chernozem soil and particles formed to simulate soils. The artificial soil particles were formed from: (1) silicas coated with manganese oxide, ferric oxide and hydrated ferric oxide, (2) silicas bearing chemically bound humic and fulvic acids and (3) alumina bearing anionically associated humic acid. These investigations have established that uptake of {sup 110m}Ag(I) by the humate coatings of soil particles will predominate under a wide range of pH. In the absence of humate coatings on the soil particles the radionuclide will be bound by the Fe/Mn oxide fractions of soils.

Investigations of the sorption characteristics of radiosilver on some natural and artificial soil particles

International Nuclear Information System (INIS)

Szabo, Gyula; Guczi, Judit; Valyon, Jozef; Bulman, Robert A.

1995-01-01

The likely distribution of 110m Ag(I), a radionuclide that may be produced in nuclear power stations and which has been known to contaminate the environment, between the components of particles of soil has been investigated by measuring its uptake from solutions of sodium nitrate, sodium EDTA and sodium citrate onto particles of chernozem soil and particles formed to simulate soils. The artificial soil particles were formed from: (1) silicas coated with manganese oxide, ferric oxide and hydrated ferric oxide, (2) silicas bearing chemically bound humic and fulvic acids and (3) alumina bearing anionically associated humic acid. These investigations have established that uptake of 110m Ag(I) by the humate coatings of soil particles will predominate under a wide range of pH. In the absence of humate coatings on the soil particles the radionuclide will be bound by the Fe/Mn oxide fractions of soils

Labeling suspended aerosol particles with short-lived radionuclides for determination of particle deposition

International Nuclear Information System (INIS)

Smith, M.F.; Bryant, S.; Welch, S.; Digenis, G.A.

1984-01-01

Radiotracer techniques were developed to examine parameters that characterize pressurized aerosols designed to deliver insoluble particles suspended in the aerosol formulation. Microaggregated bovine serum albumin microspheres that were to be suspended were labeled with iodine-131 (t1/2 . 8 d). This iodination procedure (greater than 80% effective) is also applicable to iodine-123, which possesses superior characteristics for external imaging and further in vivo studies. This report shows that for pressurized aerosols containing suspended particles, each metered dose is approximately equal (not including the priming doses and the emptying doses). Increase in the delivery of the albumin particles out of the canister was best achieved by pretreating the valve assembly with a solution of 2% (w/v) bovine serum albumin in phosphate buffer. Use of a cascade impactor delineated the particle size distribution of the micropheres, with the majority of particles ranging in size from 2 to 8 microns. The data disclosed here indicate that the techniques developed with short-lived radionuclides can be used to quantitate each metered dose, characterize the particle size distribution profile of the aerosol contents, and determine the extent of deposition of the particles in the aerosol canister and all of its components

Fractals control in particle's velocity

International Nuclear Information System (INIS)

Zhang Yongping; Liu Shutang; Shen Shulan

2009-01-01

Julia set, a fractal set of the literature of nonlinear physics, has significance for the engineering applications. For example, the fractal structure characteristics of the generalized M-J set could visually reflect the change rule of particle's velocity. According to the real world requirement, the system need show various particle's velocity in some cases. Thus, the control of the nonlinear behavior, i.e., Julia set, has attracted broad attention. In this work, an auxiliary feedback control is introduced to effectively control the Julia set that visually reflects the change rule of particle's velocity. It satisfies the performance requirement of the real world problems.

Characterization of calcium carbonate sorbent particle in furnace environment

Energy Technology Data Exchange (ETDEWEB)

Lee, Kang Soo [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Jung, Jae Hee [Environment Sensor System Research Center, KIST 39-1 Hawolgok-dong, Seongbuk-gu, Seoul, 136-791 (Korea, Republic of); Keel, Sang In; Yun, Jin Han; Min, Tai Jin [Environmental Systems Research Division, KIMM 104 Sinseongno, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Kim, Sang Soo, E-mail: sskim@kaist.ac.kr [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

2012-07-01

The oxy-fuel combustion system is a promising technology to control CO{sub 2} and NO{sub X} emissions. Furthermore, sulfation reaction mechanism under CO{sub 2}-rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO{sub 3}) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO{sub 3}, which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO{sub 3} sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO{sub 2} atmosphere due to the higher CO{sub 2} partial pressure. Instead, the sintering effect was dominant in the CO{sub 2} atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain-subgrain structure model in both the air and CO{sub 2} atmospheres.

Characterization of calcium carbonate sorbent particle in furnace environment

International Nuclear Information System (INIS)

Lee, Kang Soo; Jung, Jae Hee; Keel, Sang In; Yun, Jin Han; Min, Tai Jin; Kim, Sang Soo

2012-01-01

The oxy-fuel combustion system is a promising technology to control CO 2 and NO X emissions. Furthermore, sulfation reaction mechanism under CO 2 -rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO 3 ) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO 3 , which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO 3 sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO 2 atmosphere due to the higher CO 2 partial pressure. Instead, the sintering effect was dominant in the CO 2 atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain–subgrain structure model in both the air and CO 2 atmospheres.

Optimizing parameter of particle damping based on Leidenfrost effect of particle flows

Science.gov (United States)

Lei, Xiaofei; Wu, Chengjun; Chen, Peng

2018-05-01

Particle damping (PD) has strongly nonlinearity. With sufficiently vigorous vibration conditions, it always plays excellent damping performance and the particles which are filled into cavity are on Leidenfrost state considered in particle flow theory. For investigating the interesting phenomenon, the damping effect of PD on this state is discussed by the developed numerical model which is established based on principle of gas and solid. Furtherly, the numerical model is reformed and applied to study the relationship of Leidenfrost velocity with characteristic parameters of PD such as particle density, diameter, mass packing ratio and diameter-length ratio. The results indicate that particle density and mass packing ratio can drastically improve the damping performance as opposed as particle diameter and diameter-length ratio, mass packing ratio and diameter-length ratio can low the excited intensity for Leidenfrost state. For discussing the application of the phenomenon in engineering, bound optimization by quadratic approximation (BOBYQA) method is employed to optimize mass packing ratio of PD for minimize maximum amplitude (MMA) and minimize total vibration level (MTVL). It is noted that the particle damping can drastically reduce the vibrating amplitude for MMA as Leidenfrost velocity equal to the vibrating velocity relative to maximum vibration amplitude. For MTVL, larger mass packing ratio is best option because particles at relatively wide frequency range is adjacent to Leidenfrost state.

Sub-micron particle number size distribution characteristics at two urban locations in Leicester

Science.gov (United States)

Hama, Sarkawt M. L.; Cordell, Rebecca L.; Kos, Gerard P. A.; Weijers, E. P.; Monks, Paul S.

2017-09-01

The particle number size distribution (PNSD) of atmospheric particles not only provides information about sources and atmospheric processing of particles, but also plays an important role in determining regional lung dose. Owing to the importance of PNSD in understanding particulate pollution two short-term campaigns (March-June 2014) measurements of sub-micron PNSD were conducted at two urban background locations in Leicester, UK. At the first site, Leicester Automatic Urban Rural Network (AURN), the mean number concentrations of nucleation, Aitken, accumulation modes, the total particles, equivalent black carbon (eBC) mass concentrations were 2002, 3258, 1576, 6837 # cm-3, 1.7 μg m-3, respectively, and at the second site, Brookfield (BF), were 1455, 2407, 874, 4737 # cm-3, 0.77 μg m-3, respectively. The total particle number was dominated by the nucleation and Aitken modes, with both consisting of 77%, and 81% of total number concentrations at AURN and BF sites, respectively. This behaviour could be attributed to primary emissions (traffic) of ultrafine particles and the temporal evolution of mixing layer. The size distribution at the AURN site shows bimodal distribution at 22 nm with a minor peak at 70 nm. The size distribution at BF site, however, exhibits unimodal distribution at 35 nm. This study has for the first time investigated the effect of Easter holiday on PNSD in UK. The temporal variation of PNSD demonstrated a good degree of correlation with traffic-related pollutants (NOX, and eBC at both sites). The meteorological conditions, also had an impact on the PNSD and eBC at both sites. During the measurement period, the frequency of NPF events was calculated to be 13.3%, and 22.2% at AURN and BF sites, respectively. The average value of formation and growth rates of nucleation mode particles were 1.3, and 1.17 cm-3 s-1 and 7.42, and 5.3 nm h-1 at AURN, and BF sites, respectively. It can suggested that aerosol particles in Leicester originate mainly

Spin analysis of supersymmetric particles

International Nuclear Information System (INIS)

Choi, S.Y.; Martyn, H.U.

2006-12-01

The spin of supersymmetric particles can be determined at e + e - colliders unambiguously. This is demonstrated for a characteristic set of non-colored supersymmetric particles -- smuons, selectrons, and charginos/neutralinos. The analysis is based on the threshold behavior of the excitation curves for pair production in e + e - collisions, the angular distribution in the production process and decay angular distributions. In the first step we present the observables in the helicity formalism for the supersymmetric particles. Subsequently we confront the results with corresponding analyses of Kaluza-Klein particles in theories of universal extra space dimensions which behave distinctly different from supersymmetric theories. It is shown in the third step that a set of observables can be designed which signal the spin of supersymmetric particles unambiguously without any model assumptions. Finally in the fourth step it is demonstrated that the determination of the spin of supersymmetric particles can be performed experimentally in practice at an e + e - collider. (orig.)

Characteristics of Ambient Black Carbon Mass and Size-Resolved Particle Number Concentrations during Corn Straw Open-Field Burning Episode Observations at a Rural Site in Southern Taiwan.

Science.gov (United States)

Cheng, Yu-Hsiang; Yang, Li-Sing

2016-07-08

Information on the effect of open-field burning of agricultural residues on ambient black carbon (BC) mass and size-resolved particle number concentrations is scarce. In this study, to understand the effect of such open-field burning on short-term air quality, real-time variations of the BC mass and size-resolved particle number concentrations were monitored before and during a corn straw open-field burning episode at a rural site. Correlations between the BC mass and size-resolved particle number concentrations during the episode were investigated. Moreover, the particle number size distribution and absorption Ångström exponent were determined for obtaining the characteristics of aerosol emissions from the corn straw open-field burning. The results can be used to address public health concerns and as a reference for managing similar episodes of open-field burning of agricultural residues.

Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: Prescribed burns and wildfires

Science.gov (United States)

McCluskey, Christina S.

Insufficient knowledge regarding the sources and number concentrations of atmospheric ice nucleating particles (INP) leads to large uncertainties in understanding the interaction of aerosols with cloud processes, such as cloud life time and precipitation rates. This study utilizes measurements of INP from a diverse set of biomass burning events to better understand INP associated with biomass burning in the U.S. Prescribed burns in Georgia and Colorado, two Colorado wildfires and two laboratory burns were monitored for INP number concentrations. The relationship between nINP and total particle number concentrations, evident within prescribed burning plumes, was degraded within aged smoke plumes from the wildfires, limiting the utility of this relationship for comparing laboratory and field data. Larger particles, represented by n500nm, are less vulnerable to plume processing and have previously been evaluated for their relation to nINP. Our measurements indicated that for a given n500nm, nINP associated with the wildfires were nearly an order of magnitude higher than nINP found in prescribed fire emissions. Reasons for the differences between INP characteristics in these emissions were explored, including variations in combustion efficiency, fuel type, transport time and environmental conditions. Combustion efficiency and fuel type were eliminated as controlling factors by comparing samples with contrasting combustion efficiencies and fuel types. Transport time was eliminated because the expected impact would be to reduce n500nm, thus resulting in the opposite effect from the observed change. Bulk aerosol chemical composition analyses support the potential role of elevated soil dust particle concentrations during the fires, contributing to the population of INP, but the bulk analyses do not target INP composition directly. It is hypothesized that both hardwood burning and soil lofting are responsible for the elevated production of INP in the Colorado wildfires in

Measuring the rebound effect with micro data

DEFF Research Database (Denmark)

de Borger, Bruno; Mulalic, Ismir; Rouwendal, Jan

by conventional theory) but also estimate versions in which the coefficients for fuel price and fuel efficiency can differ. We use administrative register micro data over the period 2004- 2010 to estimate the demand equation. We apply fixed-effect panel-data (first-diff.) techniques. The focus is on car users...... that switch cars during the period of observation. Endogeneity of the fuel efficiency of the new car is an important concern. We deal with endogeneity of car characteristics, following Berry, Levinsohn and Pakes (1995), by instrumenting them using the characteristic of the old car relative to the average...

Population characteristics of submicrometer-sized craters on regolith particles from asteroid Itokawa

Science.gov (United States)

Matsumoto, Toru; Hasegawa, S.; Nakao, S.; Sakai, M.; Yurimoto, H.

2018-03-01

We investigated impact crater structures on regolith particles from asteroid Itokawa using scanning electron microscopy. We observed the surfaces of 51 Itokawa particles, ranging from 15 μm to 240 μm in size. Craters with average diameters ranging from 10 nm to 2.8 μm were identified on 13 Itokawa particles larger than 80 μm. We examined the abundance, spatial distribution, and morphology of approximately 900 craters on six Itokawa particles. Craters with sizes in excess of 200 nm are widely dispersed, with spatial densities from 2.6 μm2 to 4.5 μm2; a fraction of the craters was locally concentrated with a density of 0.1 μm2. The fractal dimension of the cumulative crater diameters ranges from 1.3 to 2.3. Craters of several tens of nanometers in diameter exhibit pit and surrounding rim structures. Craters of more than 100 nm in diameter commonly have melted residue at their bottom. These morphologies are similar to those of submicrometer-sized craters on lunar regolith. We estimated the impactor flux on Itokawa regolith-forming craters, assuming that the craters were accumulated during direct exposure to the space environment for 102 to 104 yr. The range of impactor flux onto Itokawa particles is estimated to be at least one order of magnitude higher than the interplanetary dust flux and comparable to the secondary impact flux on the Moon. This indicates that secondary ejecta impacts are probably the dominant cratering process in the submicrometer range on Itokawa regolith particles, as well as on the lunar surface. We demonstrate that secondary submicrometer craters can be produced anywhere in centimeter- to meter-sized depressions on Itokawa's surface through primary interplanetary dust impacts. If the surface unevenness on centimeter to meter scales is a significant factor determining the abundance of submicrometer secondary cratering, the secondary impact flux could be independent of the overall shapes or sizes of celestial bodies, and the secondary

Mean Characteristics of Conical Vortices Above Roof Eaves of Low–Rise Cubic Buildings Using Particle Image Velocimetry

Directory of Open Access Journals (Sweden)

M. Gamboa–Marrufo

2009-04-01

Full Text Available Fluctuating low pressures near the edges of flat roofs are often caused when the wind impinges on one corner of the building so that conical vortices form above the diagonal roof edges. In turbulent flow, these vortices vary in position and strength and the underlying surface pressures fluctuate accordingly. A preliminary approach to the study of the mechanism linking instantaneous roof edge pressures with the wind vortical structures involves the evaluation of mean characteristics and positions of the latter. However the flow examination has so far been severely limited by the restriction of available anemometers to single–point sampling. In this experimental study, a 200mm cube has been used to model a building with a flat square roof set at an angle of 45° to the oncoming flow direction, and a Particle Image Velocimetry system was used to capture instantaneous two–dimensional velocity vector images of entire flow cross–sections, both normal to the vortex axis and in planes parallel to that axis. The se vector maps were used to estimate the mean characteristics of the vortices and appropriate observation–plane directions to measure wind velocities in the study of the instantaneous problem.

A re-examination of symmetry/Group relationships as applied ot the elementary particles

International Nuclear Information System (INIS)

Byrd, K.; Cole R.

1993-01-01

The purpose of this investigation is to apply Group Theory to the elementary particles. Group Theory is a mathematical discipline used to predict the existence of elementary particles by physicists. Perhaps, the most famous application of Group Theory to the elementary particles was by Murray Gell-Mann in 1964. Gell-Mann used the theory to predict the existence and characteristics of the then undiscovered Omega Minus Particle. Group Theory relies heavily on symmetry relationships and expresses them in terms of geometry. Existence and the characteristics of a logical intuitable, but unobserved member of a group are given by extrapolation of the geometric relationships and characteristics of the known members of the group. In this study, the Delta, Sigma, Chi and Omega baryons are used to illustrate how physicists apply geometry and symmetrical relationships to predict new particles. The author's hypothesis is that by using the D3 crystal symmetry group and Gell-Mann's baryons, three new particles will be predicted. The results of my new symmetry predicts the Omega 2, Omega 3, and Chi 3. However, the Chi 3 does not have characteristics consistent with those of the other known group members

Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park.

Science.gov (United States)

Li, Haiyan; Shi, Anbang; Zhang, Xiaoran

2015-06-01

Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments (RDSs) of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents' and tourists' health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size (Pb>Cu>Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order: Cd>Zn≈Pb>Cu. Copyright © 2015. Published by Elsevier B.V.

Clinical results in heavy particle radiotherapy

International Nuclear Information System (INIS)

Castro, J.R.; Quivey, J.M.; Saunders, W.M.; Woodruff, K.H.; Chen, G.T.Y.; Lyman, J.T.; Pitluck, S.; Tobias, C.A.; Walton, R.E.; Peters, T.C.

1980-01-01

The chapter presents an overview of the use of heavy particles in human cancer radiotherapy. The biophysical characteristics and rationale for using heavy charged particle therapy are explored. The clinical experience with carbon, neon, argon and helium are summarized for various types of tumors including carcinomas of the uterine cervix and lung, skin melanomas and metastatic sarcomas. No obvious normal tissue complications have appeared

Health Insurance In China: After Declining In The 1990s, Coverage Rates Rebounded To Near-Universal Levels By 2011.

Science.gov (United States)

Li, Yanping; Malik, Vasanti; Hu, Frank B

2017-08-01

We analyzed trends in rates of health insurance coverage in China in the period 1991-2011 and the association of health insurance with hypertension and diabetes based on data from eight waves of the China Health and Nutrition Survey. The rate of coverage fell from 32.3 percent in 1991 to 21.9 percent in 2000, rebounding to 49.7 percent in 2006 and then rapidly climbing to 94.7 percent in 2011. Our study indicated that neither the prevalence of diabetes nor that of hypertension was significantly associated with health insurance coverage. When patients were aware of their condition or disease, those with insurance had a significantly higher likelihood of treatment for diabetes and hypertension, compared to those without insurance. We observed an association between health insurance coverage and seeking preventive care and receiving medical treatment when patients were aware of their condition or disease. Project HOPE—The People-to-People Health Foundation, Inc.

Energetic particle perspective of the magnetopause

International Nuclear Information System (INIS)

Williams, D.J.; Fritz, T.A.; Wilken, B.; Keppler, E.

1979-01-01

We present a detailed analysis of energetic (>24 keV) particle data obtained from the Isee satellites during a series of magnetopause crossings which occurred at 0000--0400 hours UT (approx.1030 hours LT) on November 20, 1977. The primary energetic particle data used are the three-dimensional distributions obtained from the Isee A satellite. Correlative magnetic field measurements are used to relate the particle behavior to magnetic field characteristics at and earthward of the magnetopause. We find that to first order the magnetopause can be regarded as a perfectly absorbing boundary for trapped >24-keV particles, that it is nearly alway in motion, and that boundary waves are often present. We find that the observed dayside magnetopause motion is consistent with a large-scale radial motion having an approx.10-min period plus superimposed boundary waves with a 90- to 150-s period. More qualitatively, we find that the data require a third and longer period (approx. 30 min) magnetopause motion upon which the above, shorter-period motions are superimposed. Consistent with the picture of absorbing boundary, we find no evidence of microturbulent processes at the magnetopause which significantly affect the directional trapped particle flux to within 9--36 km of the boundary. We therefore conclude that the radial gradient to the magnetopause observed in the directional, >24-keV, dayside, near-equatorial, magnetospherically trapped particle flux is due to internal magnetospheric processes. Just outside the magnetopause in the magnetosheath we observe a broad (approximately hemispherical) field-aligned flow of >24-keV ions away from the magnetosphere. The absolute intensity and spectral characteristics of this flow and its relation to the magnetopause and the trapped particle population indicate that it is formed by the leakage of trapped particles from the radiation belts

Potential for heavy particle radiation therapy

International Nuclear Information System (INIS)

Raju, M.R.; Phillips, T.L.

1977-03-01

Radiation therapy remains one of the major forms of cancer treatment. When x rays are used in radiotherapy, there are large variations in radiation sensitivity among tumors because of the possible differences in the presence of hypoxic but viable tumor cells, differences in reoxygenation during treatment, differences in distribution of the tumor cells in their cell cycle, and differences in repair of sublethal damage. When high-LET particles are used, depending upon the LET distribution, these differences are reduced considerably. Because of these differences between x rays and high-LET particle effects, the high-LET particles may be more effective on tumor cells for a given effect on normal cells. Heavy particles have potential application in improving radiotherapy because of improved dose localization and possible advantages of high-LET particles due to their radiobiological characteristics. Protons, because of their defined range, Bragg peak, and small effects of scattering, have good dose localization characteristics. The use of protons in radiotherapy minimizes the morbidity of radiotherapy treatment and is very effective in treating deep tumors located near vital structures. Fast neutrons have no physical advantages over 60 Co gamma rays but, because of their high-LET component, could be very effective in treating tumors that are resistant to conventional radiations. Negative pions and heavy ions combine some of the advantages of protons and fast neutrons

Dewatering behaviour of ultrafine hard coal particles

Energy Technology Data Exchange (ETDEWEB)

Fischer, D.; Alizadeh, A.; Simonis, W.

1986-03-01

With decreasing particle diameter distribution the dewatering behaviour of coal gets increasingly complicated. A correlation between final moisture and content of particles below 25..mu..m in the course of centrifuging can be verified. This behaviour of the particles below 25..mu..m can be explained by the great specific surface, on the one hand, and by the distribution of the surface charge density, on the other hand. The charge density depends on the type of coal, on the minerals content and their make-up, as well as on the characteristics of the surrounding medium. The surface charge can be measured indirectly. Varying electrophoretic mobilities of the particles are observed in dependence on the type of raw material. In the neutral pH-range, minerals have a negative surface charge, while coal has a positive one. By way of adding reagents it is possible to invert the negative charges with complicated dewatering characteristics into positive charges. A similar influence will be exerted by changing the pH-value. 6 references.

Empirically characteristic analysis of chaotic PID controlling particle swarm optimization.

Science.gov (United States)

Yan, Danping; Lu, Yongzhong; Zhou, Min; Chen, Shiping; Levy, David

2017-01-01

Since chaos systems generally have the intrinsic properties of sensitivity to initial conditions, topological mixing and density of periodic orbits, they may tactfully use the chaotic ergodic orbits to achieve the global optimum or their better approximation to given cost functions with high probability. During the past decade, they have increasingly received much attention from academic community and industry society throughout the world. To improve the performance of particle swarm optimization (PSO), we herein propose a chaotic proportional integral derivative (PID) controlling PSO algorithm by the hybridization of chaotic logistic dynamics and hierarchical inertia weight. The hierarchical inertia weight coefficients are determined in accordance with the present fitness values of the local best positions so as to adaptively expand the particles' search space. Moreover, the chaotic logistic map is not only used in the substitution of the two random parameters affecting the convergence behavior, but also used in the chaotic local search for the global best position so as to easily avoid the particles' premature behaviors via the whole search space. Thereafter, the convergent analysis of chaotic PID controlling PSO is under deep investigation. Empirical simulation results demonstrate that compared with other several chaotic PSO algorithms like chaotic PSO with the logistic map, chaotic PSO with the tent map and chaotic catfish PSO with the logistic map, chaotic PID controlling PSO exhibits much better search efficiency and quality when solving the optimization problems. Additionally, the parameter estimation of a nonlinear dynamic system also further clarifies its superiority to chaotic catfish PSO, genetic algorithm (GA) and PSO.

Empirically characteristic analysis of chaotic PID controlling particle swarm optimization.

Directory of Open Access Journals (Sweden)

Danping Yan

Full Text Available Since chaos systems generally have the intrinsic properties of sensitivity to initial conditions, topological mixing and density of periodic orbits, they may tactfully use the chaotic ergodic orbits to achieve the global optimum or their better approximation to given cost functions with high probability. During the past decade, they have increasingly received much attention from academic community and industry society throughout the world. To improve the performance of particle swarm optimization (PSO, we herein propose a chaotic proportional integral derivative (PID controlling PSO algorithm by the hybridization of chaotic logistic dynamics and hierarchical inertia weight. The hierarchical inertia weight coefficients are determined in accordance with the present fitness values of the local best positions so as to adaptively expand the particles' search space. Moreover, the chaotic logistic map is not only used in the substitution of the two random parameters affecting the convergence behavior, but also used in the chaotic local search for the global best position so as to easily avoid the particles' premature behaviors via the whole search space. Thereafter, the convergent analysis of chaotic PID controlling PSO is under deep investigation. Empirical simulation results demonstrate that compared with other several chaotic PSO algorithms like chaotic PSO with the logistic map, chaotic PSO with the tent map and chaotic catfish PSO with the logistic map, chaotic PID controlling PSO exhibits much better search efficiency and quality when solving the optimization problems. Additionally, the parameter estimation of a nonlinear dynamic system also further clarifies its superiority to chaotic catfish PSO, genetic algorithm (GA and PSO.

Physicochemical and toxicological characteristics of welding fume derived particles generated from real time welding processes.

Science.gov (United States)

Chang, Cali; Demokritou, Philip; Shafer, Martin; Christiani, David

2013-01-01

Welding fume particles have been well studied in the past; however, most studies have examined welding fumes generated from machine models rather than actual exposures. Furthermore, the link between physicochemical and toxicological properties of welding fume particles has not been well understood. This study aims to investigate the physicochemical properties of particles derived during real time welding processes generated during actual welding processes and to assess the particle size specific toxicological properties. A compact cascade impactor (Harvard CCI) was stationed within the welding booth to sample particles by size. Size fractionated particles were extracted and used for both off-line physicochemical analysis and in vitro cellular toxicological characterization. Each size fraction was analyzed for ions, elemental compositions, and mass concentration. Furthermore, real time optical particle monitors (DustTrak™, TSI Inc., Shoreview, Minn.) were used in the same welding booth to collect real time PM2.5 particle number concentration data. The sampled particles were extracted from the polyurethane foam (PUF) impaction substrates using a previously developed and validated protocol, and used in a cellular assay to assess oxidative stress. By mass, welding aerosols were found to be in coarse (PM 2.5–10), and fine (PM 0.1–2.5) size ranges. Most of the water soluble (WS) metals presented higher concentrations in the coarse size range with some exceptions such as sodium, which presented elevated concentration in the PM 0.1 size range. In vitro data showed size specific dependency, with the fine and ultrafine size ranges having the highest reactive oxygen species (ROS) activity. Additionally, this study suggests a possible correlation between welders' experience, the welding procedure and equipment used and particles generated from welding fumes. Mass concentrations and total metal and water soluble metal concentrations of welding fume particles may be

A comparative study of the ignition and burning characteristics of after burning aluminum and magnesium particles

International Nuclear Information System (INIS)

Lim, Ji Hwan; Lee, Sang Hyup; Yoon, Woong Sup

2014-01-01

Ignition and the burning of air-born single aluminum and magnesium particles are experimentally investigated. Particles of 30 to 106 μm-diameters were electrodynamically levitated, ignited, and burnt in atmospheric air. The particle combustion evolution was recorded by high-speed cinematography. Instant temperature and thermal radiation intensity were measured using two-wavelength pyrometry and photomultiplier tube methods. Ignition of the magnesium particle is prompt and substantially advances the aluminum particle by 10 ms. Burning time of the aluminum particles is extended 3 to 5 times longer than the magnesium particles. Exponents of a power-law fit of the burning rates are 1.55 and 1.24 for aluminum and magnesium particles, respectively. Flame temperature is slightly lower than the oxide melting temperature. For the aluminum, dimensionless flame diameter is inert to the initial particle size, but for the magnesium inversely proportional to the initial diameter.

A comparative study of the ignition and burning characteristics of after burning aluminum and magnesium particles

Energy Technology Data Exchange (ETDEWEB)

Lim, Ji Hwan; Lee, Sang Hyup; Yoon, Woong Sup [Yonsei University, Seoul (Korea, Republic of)

2014-10-15

Ignition and the burning of air-born single aluminum and magnesium particles are experimentally investigated. Particles of 30 to 106 μm-diameters were electrodynamically levitated, ignited, and burnt in atmospheric air. The particle combustion evolution was recorded by high-speed cinematography. Instant temperature and thermal radiation intensity were measured using two-wavelength pyrometry and photomultiplier tube methods. Ignition of the magnesium particle is prompt and substantially advances the aluminum particle by 10 ms. Burning time of the aluminum particles is extended 3 to 5 times longer than the magnesium particles. Exponents of a power-law fit of the burning rates are 1.55 and 1.24 for aluminum and magnesium particles, respectively. Flame temperature is slightly lower than the oxide melting temperature. For the aluminum, dimensionless flame diameter is inert to the initial particle size, but for the magnesium inversely proportional to the initial diameter.

Discharge time dependence of a solution plasma process for colloidal copper nanoparticle synthesis and particle characteristics

International Nuclear Information System (INIS)

Pootawang, Panuphong; Saito, Nagahiro; Lee, Sang Yul

2013-01-01

In this study, we investigate a new synthetic route, termed the solution plasma process, for the synthesis of colloidal copper nanoparticles (CuNPs) in the presence of an amide and acid capping agent. Gelatin and ascorbic acid were selected as the capping agents to protect the particles against coalescence and oxidation side reaction. Using a high voltage power supply, CuNPs were rapidly formed by 1 min after the discharge. The size and shape of the CuNPs were dependent on the discharge time and were clearly influenced by the effect of the capping agents under two characteristics of the discharge medium (pH and temperature). With a long discharge time, the CuNP size tended to decrease with the formation of anisotropic particle morphologies: spherical, cubic, hexagonal, triangular and rod-like shapes. The decrease in CuNP size as a function of discharge time could be explained by the dissolution of CuNPs in a lower pH solution. After 5 min discharge the capping agent evidently allowed the protection of the synthesized CuNPs against oxidation with the presence of anisotropic CuNP shapes. It is demonstrated that the CuNP shape could be tuned from spherical to anisotropic shapes without the undesirable oxidation by adjusting the discharge time of the solution plasma. These advantages are valuable for material engineering to design the properties of Cu-based nanoparticles for the desired applications. (paper)

Collisions of droplets on spherical particles

Science.gov (United States)

Charalampous, Georgios; Hardalupas, Yannis

2017-10-01

Head-on collisions between droplets and spherical particles are examined for water droplets in the diameter range between 170 μm and 280 μm and spherical particles in the diameter range between 500 μm and 2000 μm. The droplet velocities range between 6 m/s and 11 m/s, while the spherical particles are fixed in space. The Weber and Ohnesorge numbers and ratio of droplet to particle diameter were between 92 deposition and splashing regimes, a regime is observed in the intermediate region, where the droplet forms a stable crown, which does not breakup but propagates along the particle surface and passes around the particle. This regime is prevalent when the droplets collide on small particles. The characteristics of the collision at the onset of rim instability are also described in terms of the location of the film on the particle surface and the orientation and length of the ejected crown. Proper orthogonal decomposition identified that the first 2 modes are enough to capture the overall morphology of the crown at the splashing threshold.

Particle platforms for cancer immunotherapy

Directory of Open Access Journals (Sweden)

Serda RE

2013-04-01

Full Text Available Rita Elena Serda Department of Nanomedicine, The Methodist Hospital Research Institute, Houston, TX, USA Abstract: Elevated understanding and respect for the relevance of the immune system in cancer development and therapy has led to increased development of immunotherapeutic regimens that target existing cancer cells and provide long-term immune surveillance and protection from cancer recurrence. This review discusses using particles as immune adjuvants to create vaccines and to augment the anticancer effects of conventional chemotherapeutics. Several particle prototypes are presented, including liposomes, polymer nanoparticles, and porous silicon microparticles, the latter existing as either single- or multiparticle platforms. The benefits of using particles include immune-cell targeting, codelivery of antigens and immunomodulatory agents, and sustained release of the therapeutic payload. Nanotherapeutic-based activation of the immune system is dependent on both intrinsic particle characteristics and on the immunomodulatory cargo, which may include danger signals known as pathogen-associated molecular patterns and cytokines for effector-cell activation. Keywords: adjuvant, particle, immunotherapy, dendritic cell, cancer, vaccine

Current technology of particle physics detectors

International Nuclear Information System (INIS)

Ludlam, T.W.

1986-01-01

A brief discussion is given of the characteristics required of new accelerator facilities, leading into a discussion of the required detectors, including position sensitive detectors, particle identification, and calorimeters

Particle Entrainment in Spherical-Cap Wakes

Energy Technology Data Exchange (ETDEWEB)

Warncke, Norbert G W; Delfos, Rene; Ooms, Gijs; Westerweel, Jerry, E-mail: n.g.w.warncke@tudelft.nl [Laboratory for Aero- and Hydrodynamics, Delft University of Technology (Netherlands)

2011-12-22

In this work we study the preferential concentration of small particles in the turbulent wake behind a spherical-cap object. We present a model predicting the mean particle concentration in the near-wake as a function of the characteristic Stokes number of the problem, the turbulence level and the Froude number. We compare the model with our experimental results on this flow, measured in a vertical water tunnel.

Evaluation of rebound tonometry in red-eared slider turtles (Trachemys scripta elegans).

Science.gov (United States)

Delgado, Cherlene; Mans, Christoph; McLellan, Gillian J; Bentley, Ellison; Sladky, Kurt K; Miller, Paul E

2014-07-01

To evaluate feasibility and accuracy of intraocular pressure (IOP) measurement by rebound tonometry in adult red-eared slider turtles and determine the effects of manual and chemical restraint on IOP. Seventeen adult red-eared slider turtles. Intraocular pressure was measured with TonoLab® and TonoVet® tonometers in conscious, unrestrained turtles. To evaluate the effects of manual restraint, turtles were restrained by digital pressure on the rostral head or proximal neck. The effect of two chemical restraint protocols (dexmedetomidine, ketamine, midazolam [DKM] and dexmedetomidine, ketamine [DK] subcutaneously) on IOP was evaluated. Triplicate TonoLab® and TonoVet® readings were compared with direct manometry in three ex vivo turtle eyes. TonoLab® correlated better with manometry at IOPs < 45 mmHg than TonoVet® (linear regression slopes of 0.89 and 0.30, respectively). Mean (±SD) IOP in unrestrained conscious turtles was significantly lower (P < 0.01) with TonoLab® (10.02 ± 0.66 mmHg) than with TonoVet® (11.32 ± 1.57 mmHg). Manual neck restraint caused a significant increase in IOP (+6.31 ± 5.59 mmHg), while manual rostral head restraint did not. Both chemical restraint protocols significantly reduced IOP (DKM: −1.0 ± 0.76 mmHg; DK: −1.79 ± 1.17) compared with measurements in conscious unrestrained turtles. Chemical and manual neck restraint affected IOP. Rostral head restraint had no significant effect on IOP and is, therefore, recommended as the appropriate restraint technique in red-eared slider turtles. TonoLab® measurements estimated actual IOP more accurately, within physiologic range, than measurements obtained using the TonoVet®. © 2013 American College of Veterinary Ophthalmologists.

Exposure to ultrafine particles in relation to indoor events and dwelling characteristics

DEFF Research Database (Denmark)

Spilak, Michal; Frederiksen, Marie; Kolarik, Barbara

2014-01-01

Exposure to ultrafine particles (UFP) in homes is associated with health risks such as cardiovascular disease and/or respiratory problems. These risks are heightened by the long time that people spend indoors. Therefore reducing the particle concentration in homes leads to improved health among its....... Furthermore, the winter season was associated significantly with high UFP levels indoors. Results of our study also indicated that owning a pet, wood-type floors and floor levels close to the ground are associated with increased UFP levels....

Bubble-Induced Color Doppler Feedback for Histotripsy Tissue Fractionation.

Science.gov (United States)

Miller, Ryan M; Zhang, Xi; Maxwell, Adam D; Cain, Charles A; Xu, Zhen

2016-03-01

Histotripsy therapy produces cavitating bubble clouds to increasingly fractionate and eventually liquefy tissue using high-intensity ultrasound pulses. Following cavitation generated by each pulse, coherent motion of the cavitation residual nuclei can be detected using metrics formed from ultrasound color Doppler acquisitions. In this paper, three experiments were performed to investigate the characteristics of this motion as real-time feedback on histotripsy tissue fractionation. In the first experiment, bubble-induced color Doppler (BCD) and particle image velocimetry (PIV) analysis monitored the residual cavitation nuclei in the treatment region in an agarose tissue phantom treated with two-cycle histotripsy pulses at [Formula: see text] using a 500-kHz transducer. Both BCD and PIV results showed brief chaotic motion of the residual nuclei followed by coherent motion first moving away from the transducer and then rebounding back. Velocity measurements from both PIV and BCD agreed well, showing a monotonic increase in rebound time up to a saturation point for increased therapy dose. In a second experiment, a thin layer of red blood cells (RBC) was added to the phantom to allow quantification of the fractionation of the RBC layer to compare with BCD metrics. A strong linear correlation was observed between the fractionation level and the time to BCD peak rebound velocity over histotripsy treatment. Finally, the correlation between BCD feedback and histotripsy tissue fractionation was validated in ex vivo porcine liver evaluated histologically. BCD metrics showed strong linear correlation with fractionation progression, suggesting that BCD provides useful quantitative real-time feedback on histotripsy treatment progression.

Particle propagator of the spin Calogero–Sutherland model

International Nuclear Information System (INIS)

Nakai, Ryota; Kato, Yusuke

2014-01-01

Explicit-exact expressions for the particle propagator of the spin 1/2 Calogero–Sutherland model are derived for the system of a finite number of particles and for that in the thermodynamic limit. Derivation of the expression in the thermodynamic limit is also presented in detail. Combining this result with the hole propagator obtained in earlier studies, we calculate the spectral function of the single particle Green's function in the full range of the energy and momentum space. The resultant spectral function exhibits power-law singularity characteristic to correlated particle systems in one dimension. (paper)

MECHANISM OF PARTICLE SUSPENSION OVER A SAND WAVE

OpenAIRE

芦田, 和男; 藤田, 正治; 向井, 健

1986-01-01

The characteristics of flow vary with space over sand waves. It is important to consider thisnouniformity in the modeling of motions of suspended particles, but few methods for calculationof suspended load have been proposed by consideration of this efects. In this paper mean velocityand turbulent strength of flow are discussed experimentally over a two-dimensinal sand wave andthe motion of suspended particle are formulated using these results and authors' theory on modelof particle motion ov...

Lunar particle shadows and boundary layer experiment: plasma and energetic particles on the Apollo 15 and 16 subsatellites. Final report

International Nuclear Information System (INIS)

Anderson, K.A.; Chase, L.M.; Lin, R.P.; McCoy, J.E.; McGuire, R.E.

1974-01-01

The lunar particle shadows and boundary layer experiments aboard the Apollo 15 and 16 subsatellites and scientific reduction and analysis of the data to date are discussed with emphasis on four major topics: solar particles; interplanetary particle phenomena; lunar interactions; and topology and dynamics of the magnetosphere at lunar orbit. The studies of solar and interplanetary particles concentrated on the low energy region which was essentially unexplored, and the studies of lunar interaction pointed up the transition from single particle to plasma characteristics. The analysis concentrated on the electron angular distributions as highly sensitive indicators of localized magnetization of the lunar surface. Magnetosphere experiments provided the first electric field measurements in the distant magnetotail, as well as comprehensive low energy particle measurements at lunar distance

Friction characteristics of submicrometre-structured surfaces fabricated by particle-assisted near-field enhancement with femtosecond laser

International Nuclear Information System (INIS)

Sakai, Tetsuo; Nedyalkov, Nikolay; Obara, Minoru

2007-01-01

We present friction characteristics of sliding textured silicon surfaces at the submicrometre scale. A two-dimensional submicrometre dimple array on the Si surface is fabricated by femtosecond laser processing. Direct femtosecond laser nano-structuring of the Si (1 0 0) substrate by polystyrene particle-assisted near-field enhancement is used. In the investigated hole diameter domain from 229 to 548 nm, an increase in the friction coefficient with the decrease in the hole size is found experimentally. The fabricated submicrometre dimples act evidently as lubricant reservoirs to supply lubricants and traps to capture wear debris. The fluctuation of the friction coefficient is also increased by reducing the dimple size. The lowest friction coefficient of 1.41 x 10 -2 is achieved with the dimple array having a diameter of about 550 nm. This value is 2.6 times lower than that of non-structured substrates

Regime of aggregate structures and magneto-rheological characteristics of a magnetic rod-like particle suspension: Monte Carlo and Brownian dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Okada, Kazuya [School of Akita Prefectural University, Yurihonjo (Japan); Satoh, Akira, E-mail: asatoh@akita-pu.ac.jp [Department of Machine Intelligence and System Engineering, Akita Prefectural University, Yurihonjo (Japan)

2017-09-01

Highlights: • Monte Carlo simulations have been employed for the aggregate structures. • Brownian dynamics simulations have been employed for the magneto-rheology. • Even a weak shear flow induces a significant regime change in the aggregates. • A strong external magnetic field drastically changes the aggregates. • The dependence of the viscosity on these factors is governed in a complex manner. - Abstract: In the present study, we address a suspension composed ferromagnetic rod-like particles to elucidate a regime change in the aggregate structures and the magneto-rheological characteristics. Monte Carlo simulations have been employed for investigating the aggregate structures in thermodynamic equilibrium, and Brownian dynamics simulations for magneto-rheological features in a simple shear flow. The main results obtained here are summarized as follows. For the case of thermodynamic equilibrium, the rod-like particles aggregate to form thick chain-like clusters and the neighboring clusters incline in opposite directions. If the external magnetic field is increased, the thick chain-like clusters in the magnetic field direction grow thicker by adsorbing the neighboring clusters that incline in the opposite direction. Hence, a significant phase change in the particle aggregates is not induced by an increase in the magnetic field strength. For the case of a simple shear flow, even a weak shear flow induces a significant regime change from the thick chain-like clusters of thermodynamic equilibrium into wall-like aggregates composed of short raft-like clusters. A strong external magnetic field drastically changes these aggregates into wall-like aggregates composed of thick chain-like clusters rather than the short raft-like clusters. The internal structure of these aggregates is not strongly influenced by a shear flow, and the formation of the short raft-like clusters is maintained inside the aggregates. The main contribution to the net viscosity is the

Field dependent response of magnetorheological elastomers utilizing spherical Fe particles versus Fe nanowires

International Nuclear Information System (INIS)

Song, H J; Wereley, N M; Bell, R C; Planinsek, J L; II, J A Filer

2009-01-01

This study compares the dynamic response of nanowire-based magnetorheological elastomers (MREs), to those containing conventional spherical particles. MRE samples were fabricated by curing the iron particle laden elastomeric material in a magnetic field. Material characteristics of the MRE samples were evaluated using a material test machine that was modified to measure static and frequency dependent characteristics of these samples under different magnetic fields. The MRE samples consisted of a silicone rubber matrix containing various weight fractions of iron particles of differing morphology. Nanowires were used to enhance the interaction forces and contact area between particles. The static and dynamic properties of the MREs were evaluated under a compressive load for the various compositions and weight fractions. The stress vs. strain characteristics were measured for each sample. The equivalent damping coefficient of the MRE samples was measured and characterized under magnetic fields of differing intensities. The dynamic characteristic (dynamic stiffness) was measured under sinusoidal excitation in the frequency domain.

Experimental evidence of reduced sticking of nanoparticles on a metal grid

NARCIS (Netherlands)

Gulijk, C. van; Bal, E.A.; Schmidt-Ott, A.

2009-01-01

Filtering of NaCl, CaCl2, (NH4)2SO4 and NiSO4 aerosol particles 7–20 nm in diameter by a stainless steel grid was studied in order to find out if there is perfect sticking or partial rebound. Our experiment used particles from a spray-drying process, the majority of which were electrically neutral.

Packing Nonspherical Particles: All Shapes Are Not Created Equal

Science.gov (United States)

Torquato, Salvatore

2012-02-01

Over the past decade there has been increasing interest in the effects of particle shape on the characteristics of dense particle packings, since deviations from sphericity can lead to more realistic models of granular media, nanostructured materials, and tissue architecture. It is clear the that the broken rotational symmetry of a nonspherical particle is a crucial aspect in determining its resulting packing characteristics, but given the infinite variety of possible shapes (ellipsoids, superballs, regular and irregular polyhedra, etc.) it is desirable to formulate packing organizing principles based the particle shape. Such principles are beginning to be elucidated; see Refs. 1 and 2 and references therein. Depending upon whether the particle has central symmetry, inequivalent principle axes, and smooth or flat surfaces, we can describe the nature of its densest packing (which is typically periodic) as well as its disordered jammed states (which may or may not be isostatic). Changing the shape of a particle can dramatically alter its packing attributes. This tunability capability via particle shape could be used to tailor many-particle systems (e.g., colloids and granular media) to have designed crystal, liquid and glassy states. [4pt] [1] S. Torquato and F. H. Stillinger, ``Jammed Hard-Particle Packings: From Kepler to Bernal and Beyond," Rev. Modern Phys. 82, 2633 (2010). [0pt] [2] Y. Jiao and S. Torquato, Communication: ``A Packing of Truncated Tetrahedra That Nearly Fills All of Space and its Melting Properties," J. Chem. Phys. 135, 151101 (2011).

Three-particle forces and nuclear models

International Nuclear Information System (INIS)

Krutov, V.A.

1980-01-01

Different nuclear models accounting and unaccounting for three-particle internucleon forces (TIF) are reviewed. At present only two nuclear models use manifestly TIP: the Vautherin-Brink-Skyrme (VBS) model and the model proposed by the author of the review and called the semiphenomenological (SP) nuclear model. There is a short discussion of major drawbacks of models unaccounting for TIF: multiparticle shell model, ''superfluid model'', Harty-Fock calculations with two-particle forces, Bruckner-Hartry-Fock calculations, the relativistic self-consistent nuclear model. The VBS and SP models are discussed in detail. It is concluded, that the employment of TIF even in a very simplified form (extremely short-range) puts away a lot of problems characteristic to models limited by two-particle forces (collapse at iteratious in Hartry-Fock, simultaneous fitting of the binding energy of a nucleus and the binding energy of a nucleon, etc.) and makes it possible to obtain in a rather simple way such nuclear characteristics as nuclear binding energy, nuclear mean square root radii, nucleon density of a nucleus

Fundamental Study of Single Biomass Particle Combustion

DEFF Research Database (Denmark)

Momenikouchaksaraei, Maryam

This thesis is a comprehensive study of single biomass particle combustion. The effect of particle shape and size and operating conditions on biomass conversion characteristics were investigated experimentally and theoretically. The experimental samples were divided in two groups: particles...... well-defined conditions, and the complete combustion processes were recorded as video sequences by a CCD camera installed in the set-up. One of the project objectives is to simulate conditions reasonably close to the conditions in a power plant boiler, i.e., reasonably high temperatures (up to 1600°C...

Quantifying the motion of magnetic particles in excised tissue: Effect of particle properties and applied magnetic field

Energy Technology Data Exchange (ETDEWEB)

Kulkarni, Sandip, E-mail: sandip.d.kulkarni@gmail.com [Fischell Department of Bioengineering, University of Maryland at College Park, MD 20742 (United States); Ramaswamy, Bharath; Horton, Emily; Gangapuram, Sruthi [Fischell Department of Bioengineering, University of Maryland at College Park, MD 20742 (United States); Nacev, Alek [Weinberg Medical Physics, LLC (United States); Depireux, Didier [The Institute for Systems Research, University of Maryland at College Park, MD 20742 (United States); Otomagnetics, LLC (United States); Shimoji, Mika [Fischell Department of Bioengineering, University of Maryland at College Park, MD 20742 (United States); Otomagnetics, LLC (United States); Shapiro, Benjamin [Fischell Department of Bioengineering, University of Maryland at College Park, MD 20742 (United States); The Institute for Systems Research, University of Maryland at College Park, MD 20742 (United States); Otomagnetics, LLC (United States)

2015-11-01

This article presents a method to investigate how magnetic particle characteristics affect their motion inside tissues under the influence of an applied magnetic field. Particles are placed on top of freshly excised tissue samples, a calibrated magnetic field is applied by a magnet underneath each tissue sample, and we image and quantify particle penetration depth by quantitative metrics to assess how particle sizes, their surface coatings, and tissue resistance affect particle motion. Using this method, we tested available fluorescent particles from Chemicell of four sizes (100 nm, 300 nm, 500 nm, and 1 μm diameter) with four different coatings (starch, chitosan, lipid, and PEG/P) and quantified their motion through freshly excised rat liver, kidney, and brain tissues. In broad terms, we found that the applied magnetic field moved chitosan particles most effectively through all three tissue types (as compared to starch, lipid, and PEG/P coated particles). However, the relationship between particle properties and their resulting motion was found to be complex. Hence, it will likely require substantial further study to elucidate the nuances of transport mechanisms and to select and engineer optimal particle properties to enable the most effective transport through various tissue types under applied magnetic fields.

Experimental investigation of turbulence modulation in particle-laden coaxial jets by Phase Doppler Anemometry

Energy Technology Data Exchange (ETDEWEB)

Mergheni, M.A. [CORIA UMR 6614 CNRS, Universite et INSA de ROUEN, Avenue de l' Universite, BP 12, 76801 Saint Etienne du Rouvray, Cedex (France)]|[LESTE Ecole Nationale d' Ingenieurs de Monastir, 5019 Monastir (Tunisia); Sautet, J.C.; Godard, G. [CORIA UMR 6614 CNRS, Universite et INSA de ROUEN, Avenue de l' Universite, BP 12, 76801 Saint Etienne du Rouvray, Cedex (France); Ben Ticha, H.; Ben Nasrallah, S. [LESTE Ecole Nationale d' Ingenieurs de Monastir, 5019 Monastir (Tunisia)

2009-03-15

The effect of solid particles on the flow characteristics of axisymmetric turbulent coaxial jets for two flow conditions was studied. Simultaneous measurements of size and velocity distributions of continuous and dispersed phases in a two-phase flow are presented using a Phase Doppler Anemometry (PDA) technique. Spherical glass particles with a particle diameter range from 102 to 212 {mu}m were used in this two-phase flow, the experimental results indicate a significant influence of the solid particles and the Re on the flow characteristics. The data show that the gas phase has lower mean velocity in the near-injector region and a higher mean velocity at the developed region. Near the injector at low Reynolds number (Re = 2839) the presence of the particles dampens the gas-phase turbulence, while at higher Reynolds number (Re = 11 893) the gas-phase turbulence and the velocity fluctuation of particle-laden jets are increased. The particle velocity at higher Reynolds number (Re = 11 893) and is lower at lower Reynolds number (Re = 2839). The slip velocity between particles and gas phase existed over the flow domain was examined. More importantly, the present experiment results suggest that, consideration of the gas characteristic length scales is insufficient to predict gas-phase turbulence modulation in gas-particle flows. (author)

Identification and quantification of particle growth channels during new particle formation

Directory of Open Access Journals (Sweden)

M. R. Pennington

2013-10-01

Full Text Available Atmospheric new particle formation (NPF is a key source of ambient ultrafine particles that may contribute substantially to the global production of cloud condensation nuclei (CCN. While NPF is driven by atmospheric nucleation, its impact on CCN concentration depends strongly on atmospheric growth mechanisms since the growth rate must exceed the loss rate due to scavenging in order for the particles to reach the CCN size range. In this work, chemical composition measurements of 20 nm diameter particles during NPF in Hyytiälä, Finland, in March–April 2011 permit identification and quantitative assessment of important growth channels. In this work we show the following: (A sulfuric acid, a key species associated with atmospheric nucleation, accounts for less than half of particle mass growth during this time period; (B the sulfate content of a growing particle during NPF is quantitatively explained by condensation of gas-phase sulfuric acid molecules (i.e., sulfuric acid uptake is collision-limited; (C sulfuric acid condensation substantially impacts the chemical composition of preexisting nanoparticles before new particles have grown to a size sufficient to be measured; (D ammonium and sulfate concentrations are highly correlated, indicating that ammonia uptake is driven by sulfuric acid uptake; (E sulfate neutralization by ammonium does not reach the predicted thermodynamic end point, suggesting that a barrier exists for ammonia uptake; (F carbonaceous matter accounts for more than half of the particle mass growth, and its oxygen-to-carbon ratio (~ 0.5 is characteristic of freshly formed secondary organic aerosol; and (G differences in the overall growth rate from one formation event to another are caused by variations in the growth rates of all major chemical species, not just one individual species.

Experimental Investigation into the Combustion Characteristics on the Co-firing of Biomass with Coal as a Function of Particle Size and Blending Ratio

Energy Technology Data Exchange (ETDEWEB)

Lkhagvadorj, Sh; Kim, Sang In; Lim, Ho; Kim, Seung Mo; Jeon, Chung Hwan [Pusan National Univ., Busan (Korea, Republic of); Lee, Byoung Hwa [Doosan Heavy Industries and Construction, Ltd., Changwon (Korea, Republic of)

2016-01-15

Co-firing of biomass with coal is a promising combustion technology in a coal-fired power plant. However, it still requires verifications to apply co-firing in an actual boiler. In this study, data from the Thermogravimetric analyzer(TGA) and Drop tube furnace(DTF) were used to obtain the combustion characteristics of biomass when co-firing with coal. The combustion characteristics were verified using experimental results including reactivity from the TGA and Unburned carbon(UBC) data from the DTF. The experiment also analyzed with the variation of the biomass blending ratio and biomass particle size. It was determined that increasing the biomass blending ratio resulted in incomplete chemical reactions due to insufficient oxygen levels because of the rapid initial combustion characteristics of the biomass. Thus, the optimum blending condition of the biomass based on the results of this study was found to be 5 while oxygen enrichment reduced the increase of UBC that occurred during combustion of blended biomass and coal.

Mixing state of particles with secondary species by single particle aerosol mass spectrometer in an atmospheric pollution event

Science.gov (United States)

Xu, Lingling; Chen, Jinsheng

2016-04-01

Single particle aerosol mass spectrometer (SPAMS) was used to characterize size distribution, chemical composition, and mixing state of particles in an atmospheric pollution event during 20 Oct. - 5 Nov., 2015 in Xiamen, Southeast China. A total of 533,012 particle mass spectra were obtained and clustered into six groups, comprising of industry metal (4.5%), dust particles (2.6%), carbonaceous species (70.7%), K-Rich particles (20.7%), seasalt (0.6%) and other particles (0.9%). Carbonaceous species were further divided into EC (70.6%), OC (28.5%), and mixed ECOC (0.9%). There were 61.7%, 58.3%, 4.0%, and 14.6% of particles internally mixed with sulfate, nitrate, ammonium and C2H3O, respectively, indicating that these particles had undergone significant aging processing. Sulfate was preferentially mixed with carbonaceous particles, while nitrate tended to mix with metal-containing and dust particles. Compared to clear days, the fractions of EC-, metal- and dust particles remarkably increased, while the fraction of OC-containing particles decreased in pollution days. The mixing state of particles, excepted for OC-containing particles with secondary species was much stronger in pollution days than that in clear days, which revealed the significant influence of secondary particles in atmospheric pollution. The different activity of OC-containing particles might be related to their much smaller aerodynamic diameter. These results could improve our understanding of aerosol characteristics and could be helpful to further investigate the atmospheric process of particles.

Characterization of individual particles in gaseous media by mass spectrometry

Science.gov (United States)

Sinha, M. P.

1990-01-01

An introduction is given to a system for particle analysis by mass spectrometry (PAMS) which employs particle-beam techniques to measure mass spectra on a continuous real-time basis. The system is applied to particles of both organic and inorganic compounds, and the measurements give the chemical characteristics of particles in mixtures and indicate source apportionment. The PAMS system can be used for process control and studying heterogeneous/catalytic reactions in particles, and can be fitted to study the real-time attributes of PAMS.

Physical properties and structure of fine core-shell particles used as packing materials for chromatography Relationships between particle characteristics and column performance.

Science.gov (United States)

Gritti, Fabrice; Leonardis, Irene; Abia, Jude; Guiochon, Georges

2010-06-11

The recent development of new brands of packing materials made of fine porous-shell particles, e.g., Halo and Kinetex, has brought great improvements in potential column efficiency, demanding considerable progress in the design of chromatographic instruments. Columns packed with Halo and Kinetex particles provide minimum values of their reduced plate heights of nearly 1.5 and 1.2, respectively. These packing materials have physical properties that set them apart from conventional porous particles. The kinetic performance of 4.6mm I.D. columns packed with these two new materials is analyzed based on the results of a series of nine independent and complementary experiments: low-temperature nitrogen adsorption (LTNA), scanning electron microscopy (SEM), inverse size-exclusion chromatography (ISEC), Coulter counter particle size distributions, pycnometry, height equivalent to a theoretical plate (HETP), peak parking method (PP), total pore blocking method (TPB), and local electrochemical detection across the column exit section (LED). The results of this work establish links between the physical properties of these superficially porous particles and the excellent kinetic performance of columns packed with them. It clarifies the fundamental origin of the difference in the chromatographic performances of the Halo and the Kinetex columns. Copyright 2010 Elsevier B.V. All rights reserved.

Particles with changeable topology in nematic colloids

International Nuclear Information System (INIS)

Ravnik, Miha; Čopar, Simon; Žumer, Slobodan

2015-01-01

We show that nematic colloids can serve as a highly variable and controllable platform for studying inclusions with changeable topology and their effects on the surrounding ordering fields. We explore morphing of toroidal and knotted colloidal particles into effective spheres, distinctively changing their Euler characteristic and affecting the surrounding nematic field, including topological defect structures. With toroidal particles, the inner nematic defect eventually transitions from a wide loop to a point defect (a small loop). Trefoil particles become linked with two knotted defect loops, mutually forming a three component link, that upon tightening transform into a two-component particle-defect loop link. For more detailed topological analysis, Pontryagin-Thom surfaces are calculated and visualised, indicating an interesting cascade of defect rewirings caused by the shape morphing of the knotted particles. (paper)

Formation of light particles in nucleus-nucleus collisions

International Nuclear Information System (INIS)

Zagrebaev, V.; Penionzhkevich, Yu.

1993-01-01

The principal experimental results on the yield of the light charged particles in nucleus-nucleus collisions at the low and intermediate energies are reviewed. Inclusive spectra of light particles and their coincidences with the characteristic KX-rays, γ-rays, neutrons, projectile-like fragments, other light particles, fission fragments, and evaporation residues are analyzed. The main theoretical models used for the description of the light particle formation are briefly outlined together with their merits and shortcomings. The unsolved problems of fast light particle formation, in particular, and of nucleus-nucleus interaction dynamics, on the whole, are discussed with the outlooks of new experiments able to clear up some of these problems. (author) 144 refs., 40 figs., 2 tabs

Scattering of particles with internal degrees of freedom

International Nuclear Information System (INIS)

Slipushenko, S. V.; Tur, A. V.; Yanovsky, V. V.

2013-01-01

The scattering of particles with a small number of internal degrees of freedom is considered. Billiard formalism is used to study the scattering of two such structurally complex particles. The main scattering characteristics are found. Various types of scattering modes are revealed. In particular, a mode is detected when the velocity of motion of such particles away from each other is higher than their approach velocity before the collision. The scattering of such particles is shown to occur after a finite number of collisions. A generalized Newton law is proposed for the collision of particles with a small number of degrees of freedom, and the form of the effective coefficient of restitution is found

Numerical Study of Flow Characteristics in a Solid Particle Incinerator for Various Design Parameters of Injectors

Energy Technology Data Exchange (ETDEWEB)

Son, Jin Woo; Kim, Su Ho; Sohn, Chae Hoon [Sejong Univ., Seoul (Korea, Republic of)

2013-12-15

The flow characteristics in a solid particle incinerator are investigated numerically for high burning rate of wastes. The studied incinerator employs both a swirl flow used in the furnace of power plants and a design concept applied to a rocket combustor. As the first step, the non-reactive flow field is analyzed in the incinerator with primary and secondary injectors through which solid fuel and air are injected. The deflection angle of a primary injector, inclination angle of a secondary injector, and gap between the two types of injectors are selected as design parameters. The swirl number is adopted for evaluating the degree of swirl flow and estimated over wide ranges of three parameters. The swirl number increases with deflection angle, but it is affected little by inclination angle. Recirculation zones are formed near the injectors, and their size affects the swirl number. The swirl number decreases with the zonal size of recirculation. From the numerical results, the design points can be found with strong swirl flow.

Evolution of Particle Bed Reactor Fuel

Science.gov (United States)

Jensen, Russell R.; Evans, Robert S.; Husser, Dewayne L.; Kerr, John M.

1994-07-01

To realize the potential performance advantages inherent in a particle bed reactor (PBR) for nuclear thermal propulsion (NTP) applications, high performance particle fuel is required. This fuel must operate safely and without failure at high temperature in high pressure, flowing hydrogen propellant. The mixed mean outlet temperature of the propellant is an important characteristic of PBR performance. This temperature is also a critical parameter for fuel particle design because it dictates the required maximum fuel operating temperature. In this paper, the evolution in PBR fuel form to achieve higher operating temperatures is discussed and the potential thermal performance of the different fuel types is evaluated. It is shown that the optimum fuel type for operation under the demanding conditions in a PBR is a coated, solid carbide particle.

Visualization of acoustic particle interaction and agglomeration: Theory evaluation

International Nuclear Information System (INIS)

Hoffmann, T.L.; Koopmann, G.H.

1997-01-01

In this paper experimentally observed trajectories of particles undergoing acoustically induced interaction and agglomeration processes are compared to and validated with numerically generated trajectories based on existing agglomeration theories. Models for orthokinetic, scattering, mutual radiation pressure, and hydrodynamic particle interaction are considered in the analysis. The characteristic features of the classical orthokinetic agglomeration hypothesis, such as collision processes and agglomerations due to the relative entrainment motion, are not observed in the digital images. The measured entrainment rates of the particles are found to be consistently lower than the theoretically predicted values. Some of the experiments reveal certain characteristics which may possibly be related to mutual scattering interaction. The study's most significant discovery is the so-called tuning fork agglomeration [T. L. Hoffmann and G. H. Koopmann, J. Acoust. Soc. Am. 99, 2130 endash 2141 (1996)]. It is shown that this phenomenon contradicts the theories for mutual scattering interaction and mutual radiation pressure interaction, but agrees with the acoustic wake effect model in its intrinsic feature of attraction between particles aligned along the acoustic axis. A model by Dianov et al. [Sov. Phys. Acoust. 13 (3), 314 endash 319 (1968)] is used to describe this effect based on asymmetric flow fields around particles under Oseen flow conditions. It is concluded that this model is consistent with the general characteristics of the tuning fork agglomerations, but lacks certain refinements with respect to accurate quantification of the effect. copyright 1997 Acoustical Society of America

Research on bimodal particle extinction coefficient during Brownian coagulation and condensation for the entire particle size regime

International Nuclear Information System (INIS)

Tang Hong; Lin Jianzhong

2011-01-01

The extinction coefficient of atmospheric aerosol particles influences the earth’s radiation balance directly or indirectly, and it can be determined by the scattering and absorption characteristics of aerosol particles. The problem of estimating the change of extinction coefficient due to time evolution of bimodal particle size distribution is studied, and two improved methods for calculating the Brownian coagulation coefficient and the condensation growth rate are proposed, respectively. Through the improved method based on Otto kernel, the Brownian coagulation coefficient can be expressed simply in powers of particle volume for the entire particle size regime based on the fitted polynomials of the mean enhancement function. Meanwhile, the improved method based on Fuchs–Sutugin kernel is developed to obtain the condensation growth rate for the entire particle size regime. And then, the change of the overall extinction coefficient of bimodal distributions undergoing Brownian coagulation and condensation can be estimated comprehensively for the entire particle size regime. Simulation experiments indicate that the extinction coefficients obtained with the improved methods coincide fairly well with the true values, which provide a simple, reliable, and general method to estimate the change of extinction coefficient for the entire particle size regime during the bimodal particle dynamic processes.

Measurement of heavy particle and isotope

International Nuclear Information System (INIS)

Matsuoka, Masaru; Kohno, Takeshi; Imai, Takashi; Munakata, Kazuoki

1987-01-01

The report describes some achievements made so far in developing heavy particle and isotope measuring equipment that is planned to be mounted on the No.6 technical test satelite of the National Space Development Agency, ETS VI. Some ideas are proposed for such heavy particle and isotope measuring equipment that uses Astromag. The structure of SSD is shown which is planned to be incorporated in the sensor for the equipment. The planned charged particle detector consists of position sensitive detectors, PIN diodes and Si(Li) plates. Tests are made for the basic characteristics of such a detector. The characteristics of a PSD are also investigated. The PSD has a resolution of about 1 mm for 14 MeV He. Tests of a 0.3 mm PIN diode and 1.2 mm Si(Li) is carried out with 234 MeV-nucl Fe beams to determine their pulse height distribution. The PIN diode and Si(Li) are found to have a resolution of 6.79 and 17.6 MeV for energy loss of 158 and 710 MeV, respectively. If developed, a stripe-type Si PIN diode will serve for analysis of isotopes. A conceptual diagram of such a stripe device is proposed. The mechanism of measurement by a heavy particle and isotope detecting system incorporating Astromag is also illustrated. (Nogami, K.)

Superconducting magnets for particle large accelerators

International Nuclear Information System (INIS)

Kircher, F.

1994-01-01

The different accelerator types (linear, circular) and the advantages of using superconductivity in particle accelerator are first reviewed. Characteristics of some large superconducting accelerators (Tevatron, HERA, RHIC, LHC CERN) are presented. The design features related to accelerator magnets are reviewed: magnet reproducibility, stability, field homogeneity, etc. and the selected design characteristics are discussed: manufacturing method, winding, shielding, cryostat. CEA involvement in this domain mainly addressing quadrupoles, is presented together with the Large Hadron Collider (LHC) project at CERN. Characteristics and design of detector magnets are also described. 5 figs., 2 tabs

Digital design of multimaterial photonic particles

Science.gov (United States)

Tao, Guangming; Kaufman, Joshua J.; Shabahang, Soroush; Rezvani Naraghi, Roxana; Sukhov, Sergey V.; Joannopoulos, John D.; Fink, Yoel; Dogariu, Aristide; Abouraddy, Ayman F.

2016-01-01

Scattering of light from dielectric particles whose size is on the order of an optical wavelength underlies a plethora of visual phenomena in nature and is a foundation for optical coatings and paints. Tailoring the internal nanoscale geometry of such “photonic particles” allows tuning their optical scattering characteristics beyond those afforded by their constitutive materials—however, flexible yet scalable processing approaches to produce such particles are lacking. Here, we show that a thermally induced in-fiber fluid instability permits the “digital design” of multimaterial photonic particles: the precise allocation of high refractive-index contrast materials at independently addressable radial and azimuthal coordinates within its 3D architecture. Exploiting this unique capability in all-dielectric systems, we tune the scattering cross-section of equisized particles via radial structuring and induce polarization-sensitive scattering from spherical particles with broken internal rotational symmetry. The scalability of this fabrication strategy promises a generation of optical coatings in which sophisticated functionality is realized at the level of the individual particles. PMID:27274070

[Comparison of in vivo characteristics of polyethylene wear particles produced by a metal and a ceramic femoral component in total knee replacement].

Science.gov (United States)

Veigl, D; Vavřík, P; Pokorný, D; Slouf, M; Pavlova, E; Landor, I

2011-01-01

The aim of the study was to evaluate in vivo and compare, in terms of the quality and number of ultra high-molecular polyethylene (UHMWPE) wear particles, total knee replacements of identical construction differing only in the material used for femoral component production, i.e., CoCrMo alloy or ZrO2 ceramics. Samples of peri-prosthetic granuloma tissue were collected in two patients with total knee replacement suffering from implant migration, who were matched in relevant characteristics. The primary knee replacement in Patient 1 with a CoCrMo femoral component was done 7.2 years and in Patient 2 with a ZrO2 implant 6.8 years before this assessment. The polyethylene wear-induced granuloma was analysed by the MORF method enabling us to assess the shape and size of wear debris and the IRc method for assessment of particle concentration. In the granuloma tissue samples of Patient 1, on the average, particles were 0.30 mm in size and their relative volume was 0.19. In the Patient 2 tissue samples, the average size of particles was 0.33 mm and their relative volume was 0.26. There was no significant difference in either particle morphology or their concentration in the granuloma tissue between the two patients. One of the options of how to reduce the production of polyethylene wear particles is to improve the tribological properties of contacting surfaces in total knee replacement by substituting a cobalt-chrome femoral component with a zirconia ceramic femoral component. The previous in vitro testing carried out with a mechanical simulator under conditions approaching real weight-bearing in the human body did show a nearly three-fold decrease in the number of UHMWPE wear particles in zirconia components. The evaluation of granuloma tissue induced by the activity of a real prosthetic joint for nearly seven years, however, did not reveal any great difference in either quality or quantity of polyethylene debris between the two replacements. The difference of surface