WorldWideScience

Sample records for buses by size

  1. Physical characterization of fine particulate matter inside the public transit buses fueled by biodiesel in Toledo, Ohio

    International Nuclear Information System (INIS)

    This study presents the physical characteristics of fine particulate matter (PM) collected inside the urban-public transit buses in Toledo, OH. These buses run on 20% biodiesel blended with ultra-low sulfur diesel (ULSD) (B20). For risk analysis, it is crucial to know the modality of the size distribution and the shape factor of PM collected inside the bus. The number-size distribution, microstructure, and aspect ratio of fine PM filter samples collected in the urban-public transit buses were measured for three years (2007-2009), using an environmental scanning electron microscope (ESEM) coupled with energy dispersive X-ray spectrometry (EDX). Only the reproducible results from repeated experiments on ESEM and size distribution obtained by the GRIMM dust monitor were used in this study. The size distribution was found bi-modal in the winter and fall months and was primarily uni-modal during spring and summer. The aspect ratio for different filter samples collected inside the bus range from 2.4 to 3.6 in average value, with standard deviation ranging from 0.9 to 7.4. The square-shaped and oblong-shaped particles represent the single inhalable particle's morphology characteristics in the air of the Toledo transit buses.

  2. COMPARISON OF CLEAN DIESEL BUSES TO CNG BUSES

    Energy Technology Data Exchange (ETDEWEB)

    Lowell, D.; Parsley, W.; Bush,C; Zupo, D.

    2003-08-24

    Using previously published data on regulated and unregulated emissions, this paper will compare the environmental performance of current generation transit buses operated on compressed natural gas (CNG) to current generation transit buses operated on ultra low sulfur diesel fuel (ULSD) and incorporating diesel particulate filters (DPF). Unregulated emissions evaluated include toxic compounds associated with adverse health effects (carbonyl, PAH, NPAH, benzene) as well as PM particle count and size distribution. For all regulated and unregulated emissions, both technologies are shown to be comparable. DPF equipped diesel buses and CNG buses have virtually identical levels of PM mass emissions and particle number emissions. DPF-equipped diesel buses have lower HC and CO emissions and lower emissions of toxic substances such as benzene, carbonyls and PAHs than CNG buses. CNG buses have lower NOx emissions than DPF-equipped buses, though CNG bus NOx emissions are shown to be much more variable. In addition, this paper will compare the capital and operating costs of CNG and DPF-equipped buses. The cost comparison is primarily based on the experience of MTA New York City Transit in operating CNG buses since 1995 and DPF-equipped buses fueled with ULSD since 2001. Published data on the experience of other large transit agencies in operating CNG buses is used to validate the NYCT experience. The incremental cost (compared to ''baseline'' diesel) of operating a typical 200-bus depot is shown to be six times higher for CNG buses than for ''clean diesel'' buses. The contributors to this increased cost for CNG buses are almost equally split between increased capital costs for purchase of buses and installation of fueling infrastructure, and increased operating costs for purchase of fuel, bus maintenance, and fuel station maintenance.

  3. Particle and gaseous emissions from individual diesel and CNG buses

    Science.gov (United States)

    Hallquist, Å. M.; Jerksjö, M.; Fallgren, H.; Westerlund, J.; Sjödin, Å.

    2013-05-01

    In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III-V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN) were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel-1. In the accelerating mode, size-resolved emission factors (EFs) showed unimodal number size distributions with peak diameters of 70-90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)-1 and for the CNG buses 41 ± 26 g (kg

  4. Particle and gaseous emissions from individual diesel and CNG buses

    Directory of Open Access Journals (Sweden)

    Å. M. Hallquist

    2013-05-01

    Full Text Available In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz. The gaseous constituents (CO, HC and NO were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.. Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III–V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs with different after-treatment, including selective catalytic reduction (SCR, exhaust gas recirculation (EGR and with and without diesel particulate filter (DPF. The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel−1. In the accelerating mode, size-resolved emission factors (EFs showed unimodal number size distributions with peak diameters of 70–90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel−1 and for the CNG buses 41

  5. SIMPLIFIED METHOD FOR CALCULATING CLOSING IN OF SWITCH-GEAR FLEXIBLE BUSES AT SHORT CIRCUIT BY IMPULSE OF ELECTRODYNAMIC FORCES

    Directory of Open Access Journals (Sweden)

    I. I. Sergey

    2005-01-01

    Full Text Available The paper contains description of a simplified method for calculating closing-in of switch-gear flexible buses at short circuit. The developed method is based on integral and energy principles of  mechanics. In order to increase accuracy of the calculation corrections factors are introduced in an explicit formula for calculation of maximum horizontal deviations. These factors have been obtained with the help of a computer program that realized numerical method for calculating closing-in of wires by flexible thread levels.Diagrams are constructed with the purpose to find ymax and criteria of electro-dynamic resistance of flexible buses (permissible impulse of electro-dynamic forces and current of electro-dynamic resistance is determined.

  6. Fuel consumption reduction in urban buses by using power split transmissions

    International Nuclear Information System (INIS)

    Highlights: • Fuel consumption is highly influenced by transmission layout and control. • Continuous Variable Transmission allows control of the working point of the engine. • Hydromechanical CVT was numerically tested and compared with usual mechanical solutions. • CVT solution proved to reduce fuel consumption, improving the I.C.E. mean efficiency. • Results obtained from standard emission test cycles: New York and Manhattan Buses. - Abstract: The reduction of fuel consumption of urban vehicles is one of the challenges of the society today. Many promising technologies such as hybrid electric vehicles and fuel cells are the focus of a lot of research and investments, but high costs prevent their development on a large scale, especially in heavy duty vehicles. Simpler solutions, such as continuously variable transmissions, are then interesting alternatives: they preserve some of the advantages of hybrid solutions significantly reducing the overall cost of the system. Since these technologies allow the decoupling of the engine’s velocity from that of the wheels, optimised management of the engine becomes feasible, leading to lower fuel consumption than that of traditional solutions. This work compares the hydromechanical transmission with a traditional power shift in an application where efficiency and comfort are required: a city bus. The performance of a vehicle with a dual stage hydromechanical transmission has been investigated by means of a model implemented in the AMESim environment. A second model of a vehicle with a power shift transmission has been taken as reference solution. During the simulation of two standard test cycles, the first vehicle showed the lower fuel consumption, due to its better engine management, and to the operation of the torque converter during starts, which lowers the efficiency of the reference vehicle

  7. Non-CFC air conditioning for transit buses

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, A.A.; Parent, Y.O.; Bharathan, D.

    1992-11-01

    In the United Sates, more than 80% of transit city buses are air conditioned. Vapor compression refrigeration systems are standard for air conditioning buses and account for up to 25% of fuel consumption in the cooling season. Vapor compression devices use chlorofluorocarbons (CFCs), chemicals that contributes to Earths`s ozone depletion and to global warming. Currently, evaporative cooling is an economical alternative to CFC vapor compression refrigeration for air conditioning buses. It does not use CFCs but is restricted in use to arid climates. This limitation can be eliminated by dehumidifying the supply air using desiccants. We studied desiccant systems for cooling transit buses and found that the use of a desiccant-assisted evaporative cooling system is feasible and can deliver the required cooling. The weight and the size of the desiccant system though larger than vapor compression systems, can be easily accommodated within a bus. Fuel consumption for naming desiccant systems was about 70% less than CFC refrigeration system, resulting in payback periods of less than 2.5 years under most circumstances. This preliminary study indicated that desiccant systems combined with evaporative cooling is a CFC-free option to vapor compression refrigeration for air conditioning of transit buses. The concept is ready to be tested in a fun prototype scale in a commercial bus.

  8. Non-CFC air conditioning for transit buses

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, A.A.; Parent, Y.O.; Bharathan, D.

    1992-11-01

    In the United Sates, more than 80% of transit city buses are air conditioned. Vapor compression refrigeration systems are standard for air conditioning buses and account for up to 25% of fuel consumption in the cooling season. Vapor compression devices use chlorofluorocarbons (CFCs), chemicals that contributes to Earths's ozone depletion and to global warming. Currently, evaporative cooling is an economical alternative to CFC vapor compression refrigeration for air conditioning buses. It does not use CFCs but is restricted in use to arid climates. This limitation can be eliminated by dehumidifying the supply air using desiccants. We studied desiccant systems for cooling transit buses and found that the use of a desiccant-assisted evaporative cooling system is feasible and can deliver the required cooling. The weight and the size of the desiccant system though larger than vapor compression systems, can be easily accommodated within a bus. Fuel consumption for naming desiccant systems was about 70% less than CFC refrigeration system, resulting in payback periods of less than 2.5 years under most circumstances. This preliminary study indicated that desiccant systems combined with evaporative cooling is a CFC-free option to vapor compression refrigeration for air conditioning of transit buses. The concept is ready to be tested in a fun prototype scale in a commercial bus.

  9. Efficiency improvement of transport service by trolley buses based on the levels of their power demand

    Directory of Open Access Journals (Sweden)

    V. V. Aulin

    2014-12-01

    Full Text Available Purpose. Use efficiency improvement of trolley buses in passenger traffic based on power levels of electric energy input and terms adjustment of their maintenance. Methodology. In order to achieve this goal conformance of electric energy input by trolleybus to the transported amount of passengers taking into account characteristics of the route is offered to establish. The major indicators of the trolleybus operation are: speed of a race on lines, number of tractive motor firing, voltage and amperage in the network that were taken with accountants from a dashboard. Research results were tabulated and recorded with DVR. Along with the study of power consumption of electric energy input by a trolleybus passenger count was carried out too. Findings. The directly proportional dependence between the level of energy consumption by a trolleybus and the number of passengers for constant performance route was determined. Originality. As the criteria for evaluating the effectiveness of the trolleybus operation on the route is proposed to use the ratio between electricity consumption and number of passengers for these characteristics of the route. This is confirmed experimentally. The obtained formulas give the possibility to balance the force work and consequently the volume of energy consumption during the trolleybus movement on the rise and the descent. Practical value. The proposed criterion can be used to adjust the terms of maintenance on the individual program, that means individual maintenance (IM. Type of work performed at the IM should be determined on the basis of diagnostic data of the vehicle (V. The principles of IM were formulated: 1 the primary task is planned and preventative strategy to identify and eliminate troubleshooting and technical actions; 2 operational control of the vehicle (V technical condition on the basis of prediction of its state using the proposed criteria, that takes into account the dependence of power consumption to

  10. Was Busing the Problem?

    Science.gov (United States)

    Watras, Joseph

    2006-01-01

    On 15 April 2002, the Dayton Board of Education, the Ohio State Department of Education, and the NAACP reached an agreement ending busing for racial balance in the city schools. Participants agreed that the era for litigated desegregation was over because busing had failed to raise academic achievement of African American children and court…

  11. On-road, in-use gaseous emission measurements by remote sensing of school buses equipped with diesel oxidation catalysts and diesel particulate filters.

    Science.gov (United States)

    Burgard, Daniel A; Provinsal, Melissa N

    2009-12-01

    A remote sensing device was used to obtain on-road and in-use gaseous emission measurements from three fleets of schools buses at two locations in Washington State. This paper reports each fleet's carbon monoxide (CO), hydrocarbon (HC), nitric oxide (NO), and nitrogen dioxide (NO2) mean data. The fleets represent current emission retrofit technologies, such as diesel particulate filters and diesel oxidation catalysts, and a control fleet. This study shows that CO and HC emissions decrease with the use of either retrofit technology when compared with control buses of the same initial emission standards. The CO and HC emission reductions are consistent with published U.S. Environmental Protection Agency verified values. The total oxides of nitrogen (NOx), NO, and the NO2/NOx ratio all increase with each retrofit technology when compared with control buses. As was expected, the diesel particulate filters emitted significantly higher levels of NO2 than the control fleet because of the intentional conversion of NO to NO2 by these systems. Most prior research suggests that NOx emissions are unaffected by the retrofits; however, these previous studies have not included measurements from retrofit devices on-road and after nearly 5 yr of use. Two 2006 model-year buses were also measured. These vehicles did not have retrofit devices but were built to more stringent new engine standards. Reductions in HCs and NOx were observed for these 2006 vehicles in comparison to other non-retrofit earlier model-year vehicles. PMID:20066912

  12. Particle and gaseous emissions from individual diesel and CNG buses

    Directory of Open Access Journals (Sweden)

    Å. M. Hallquist

    2012-10-01

    Full Text Available In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz and CO2 with non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz. The gaseous constituents (CO, HC and NO were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.. Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA 3.1. The buses studied were diesel-fuelled Euro II–V and CNG-fuelled Enhanced Environmental Friendly Vehicles (EEVs with different after-treatment, including selective catalytic reduction (SCR, exhaust gas recirculation (EGR and with and without diesel particulate filter (DPF. The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN were EFPN, DPF = 8.0 ± 3.1 × 1014, EFPN, no DPF =2.8 ± 1.6 × 1015 and EFPN, CNG = 7.8 ± 5.7 × 1015 (kg fuel−1. In the accelerating mode size-resolved EFs showed unimodal number size distributions with peak diameters of 70–90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm.

    Emission

  13. Project Startup: Evaluating the Performance of Electric Buses

    Energy Technology Data Exchange (ETDEWEB)

    2016-04-01

    The National Renewable Energy Laboratory (NREL) is evaluating the in-service performance of fast-charge battery electric buses compared to compressed natural gas (CNG) buses operated by Foothill Transit in West Covina, California. Launched in 2015 in collaboration with the California Air Resources Board, this study aims to improve understanding of the overall use and effectiveness of fast-charge electric buses and associated charging infrastructure in transit operation.

  14. Interior noise profile of buses in Curitiba

    Science.gov (United States)

    Zannin, Paulo H. T.; Giovanini, Clifton R.; Diniz, Fabiano B.; Ferreira, Jose C.

    2002-11-01

    Evaluating the noise levels to which the bus drivers of Curitiba are exposed to during their working days is the main scope of this study. The city is served by an internationally known public transportation system featuring 1902 buses, which attend 1.9 million people per day. Two measurements have been taken inside each one of the 60 buses surveyed, one close to the driver and another one at the back of the bus. The results have showed that the dose levels the drivers are exposed to were below 50% in 92% out of the buses, but the normalized exposure levels were over 65 dB(A) in all cases. This level is considered as the threshold of comfort according to the Brazilian legislation on occupancy health NR-17--Ergonomics. The surveyed buses have been divided into three categories, according to their characteristics: feeder, rapid, and bi-articulated. A total of 20 buses within each category have been surveyed. Among the different categories, it has been found that the feeders have presented the highest noise levels. (To be presented in Portuguese.)

  15. SIMPLIFIED METHOD FOR CALCULATING CLOSING IN OF SWITCH-GEAR FLEXIBLE BUSES AT SHORT CIRCUIT BY IMPULSE OF ELECTRODYNAMIC FORCES

    OpenAIRE

    I. I. Sergey; E. G. Ponomarenko; W. M. Sammur; P. I. Klimkovich

    2005-01-01

    The paper contains description of a simplified method for calculating closing-in of switch-gear flexible buses at short circuit. The developed method is based on integral and energy principles of  mechanics. In order to increase accuracy of the calculation corrections factors are introduced in an explicit formula for calculation of maximum horizontal deviations. These factors have been obtained with the help of a computer program that realized numerical method for calculating closing-in of wi...

  16. Bacterial Quality of Drinking Water in Bushehr Intercity Buses in 2010

    Directory of Open Access Journals (Sweden)

    Dariush Ranjbar Vakilabadi

    2012-12-01

    Full Text Available Background and Objective: Road transportation and specifically bus travel accounts for the bulk of travel. Contaminated drinking water consumption is one of the issues that threaten health, and always there is pollution possibility in drinking water in buses. This study evaluated the microbial quality of consumed drinking water in buses and also compared it with available standards. Materials and Methods: This study is a cross-sectional study. By considering similar studies, 95% confidence interval and based on the samples size formula for tradition of proportion, 80 buses from 122 buses that entered Bushehr Passenger Depot from other cities or exited it were randomly selected. Over a three-month period, samples were taken from drinking water in these buses. Temperature, pH, residual chlorine, total coliform (TC, and fecal coliform (E. coli in each sample were measured in accordance with the standard method. Statistical analysis of the data was carried out with SPSS Version 16, and the t-test was performed for statistical difference. Results: The results showed that residual chlorine in 97.5% was zero and pH values of the samples were in the range of 6.8-8.7. TC and E. coli numbers in 12.5% and 8.8% of the samples were higher than those of standards, respectively. Conclusion: Use of ice, washing time of the drinking water tank (daily or weekly, and method of usage and storage of drinking water (with 20-liter tanks had significant effects on the bacterial loads of the drinking water in the tanks (p value <0.05. Some factors such as tank material, driver's education and age, type and model of the bus, filling time of the tank (daily or weekly, the method of filling and emptying the tank (complete clearing out of the tank or otherwise, and distance had no significant effect on the quality of the drinking water in the buses.

  17. The New Energy Buses in China

    DEFF Research Database (Denmark)

    Wang, Jingyu; Liu, Yingqi; Kokko, Ari

    2013-01-01

    With the advent of “low carbon” economy, new energy vehicles are increasingly favored by the Chinese government and manufacturers. New energy buses have become an important channel for the promotion of new energy utilizations. Based on the summary of policies, this paper conducts a thorough resea...

  18. Fine particle concentrations in buses and taxis in Florence, Italy

    Science.gov (United States)

    Fondelli, M. Cristina; Chellini, Elisabetta; Yli-Tuomi, Tarja; Cenni, Isabella; Gasparrini, Antonio; Nava, Silvia; Garcia-Orellana, Isabel; Lupi, Andrea; Grechi, Daniele; Mallone, Sandra; Jantunen, Matti

    On October 2004, a sampling survey was carried out in Florence to estimate urban fine particle exposure concentrations inside commuting vehicles during workdays characterized by heavy traffic. Portable samplers were positioned inside four regularly scheduled diesel-powered buses and four taxis during eight weekdays. Each sampler consisted of a 2.5 μm size pre-separator cyclone, a direct-reading data logging photometer (pDR-1200), and a 4 L min -1 filter sampler for the determination of PM 2.5 mass concentration. Based on reflectance analysis measurements, a PM 2.5 Black Smoke Index was determined for each filter, and the elemental composition of the PM 2.5 was analyzed by Particle Induced X-ray Emission (PIXE). PM 2.5 mass concentrations inside the vehicles correlated well with the urban ambient air PM 2.5 concentrations measured at the fixed-site monitoring stations. The PM 2.5 excess above the urban ambient level was on average 32 μg m -3 (range: 22-52 μg m -3) and 20 μg m -3 (range: 11-29 μg m -3) in buses and taxis, respectively. The PM 2.5-bound sulfur concentration was also higher in the buses than in the taxis. Based on daily Time-Microenvironment-Activity-Diary (TMAD) data, the Florentines spend on average 9.7% of their day in traffic, and the corresponding average exposure is approximately 12% of their daily PM 2.5 personal exposure. The obtained data could be used to plan interventions to minimize the PM 2.5 citizen exposures in commuting.

  19. Impact of Reconfigurable Function on Meshes with Row/Column Buses

    Directory of Open Access Journals (Sweden)

    Susumu Matsumae

    2011-01-01

    Full Text Available This paper studies the difference in computational power between the mesh-connected parallel computers equipped with dynamically reconfigurable bus systems and those with static ones. The mesh with separable buses (MSB is the mesh-connected computer with dynamically reconfigurable row/column buses. The broadcasting buses of the MSB can be dynamically sectioned into smaller bus segments by program control. We examine the impact of reconfigurable capability on the computational power of the MSB model, and investigate how computing power of the MSB decreases when we deprive the MSB of its reconfigurability. We show that any single step of the MSB of size n×n can be simulated in O(log n time by the MSB without its reconfigurable function, which means that the MSB of size n×n can work withO(log n step slowdown even if its dynamic reconfigurable function is disabled.

  20. Environmental benefits of natural gas for buses

    International Nuclear Information System (INIS)

    This paper presents a life cycle assessment comparing diesel buses with buses fueled by natural gas. The data for the emission of pollutants are based on the MEET Project of the European Commission (EC), supplemented by data measured for diesel and gas buses in Paris. The benefits of the gas fueled bus are then quantified using the damage cost estimates of the ExternE Project of the EC. A diesel bus with emissions equal to Standard EURO2 of the EC is compared with the same bus equipped with a natural gas engine, for use in Paris and in Toulouse. The damage cost of a diesel bus is significant, in the range of 0.4-1.3 euro/km. Natural gas allows an appreciable reduction of the emissions, lowering the damage cost by a factor of about 2.5 (Toulouse) to 5.5 (Paris). An approximate rule is provided for transferring the results to other cities. A sensitivity analysis is carried out to evaluate the effect of the evolution of the emissions standard towards EURO3, 4 and 5, as well as the effect of uncertainties. Finally a comparison is presented between a EURO2 diesel bus with particle filter, and a gas fueled bus with the MPI engine of IVECO, a more advanced and cleaner technology. With this engine the damage costs of the gas fueled bus are about 3-5 times lower than those of the diesel with particle filter, even though the latter has already very low emissions.(author)

  1. An Analysis of Challenges Faced by Students Learning in Virtual and Open Distance Learning System: A Case of Bindura University of Science Education (BUSE)

    Science.gov (United States)

    Dodo, Obediah; Makwerere, David; Parwada, Matavire; Parwada, Cosmas

    2013-01-01

    After realizing that the traditional modes of tuition in Zimbabwe's andragogy had either gone obsolete or over-crowded, BUSE ventured into a "virtualised" model of open and distance learning as a way of out-doing other competing universities. However, as the programme was rolled out, there came a myriad of challenges affecting the…

  2. BAE/Orion Hybrid Electric Buses at New York City Transit: A Generational Comparison (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Barnitt, R.

    2008-03-01

    Paper describes the evaluation of hybrid-electric transit buses purchased by New York City Transit (NYCT) in an order group of 200 (Gen II) and compares their performance to those of similar hybrid-electric transit buses purchased by NYCT in an order group of 125 (Gen I).

  3. The economic and environmental feasibility of biogas buses in Liege

    OpenAIRE

    Mostert, Martine; Limbourg, Sabine

    2013-01-01

    Everyday, many students at the University of Liège have to drive to the Sart-Tilman village to attend their courses. These journeys are responsible for the emission of harmful particles which have negative impacts on climate and human health. This paper analyzes the economic and environmental feasibility of using biogas buses for public transport in Liège. The idea of implementing biogas buses is based on the proposed recycling of organic waste by the company INTRADEL, which manages and treat...

  4. Air quality in inter-city buses : final report

    International Nuclear Information System (INIS)

    Various studies have suggested that air quality inside automobiles and school buses may be poorer than ambient or nearby air quality, and that concentrations of vehicle-related pollutants in city buses may be sufficiently elevated to pose concerns for vehicle occupants and operators. This paper presented the results of preliminary investigation of levels of some pollutants in inter-city buses to determine whether a fuller investigation is warranted. Another objective of the investigation was to develop methods for assessing air quality within road vehicles. Students carried monitoring equipment on 28 inter-city trips made by Greyhound Canada buses during July and August 2004. The equipment recorded average levels of carbon monoxide (CO) and nitrogen dioxide (NO2), as well as concentrations of particulate matter. Bus routes were selected that allowed for an average of 10 hours of total sampling time in a day. Data was recorded on pumps, run times and routes taken. Results indicated that levels of CO in the buses were much lower than the national standard of acceptable levels for CO. Levels of NO2 were on average lower, but 5 of the 19 recorded values exceeded acceptable levels. Average particulate levels recorded in the buses were considered acceptable, although some of the recorded levels were higher than desirable. It was concluded that further work on in-vehicle levels of NO2 and particulate matter could be warranted. Although several procedural and equipment problems were encountered, the methods used in the investigation appeared to be valid, and were thought to be suitable for further work on in-vehicle concentrations of pollutants. 21 refs

  5. Air quality in inter-city buses : final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-06-29

    Various studies have suggested that air quality inside automobiles and school buses may be poorer than ambient or nearby air quality, and that concentrations of vehicle-related pollutants in city buses may be sufficiently elevated to pose concerns for vehicle occupants and operators. This paper presented the results of preliminary investigation of levels of some pollutants in inter-city buses to determine whether a fuller investigation is warranted. Another objective of the investigation was to develop methods for assessing air quality within road vehicles. Students carried monitoring equipment on 28 inter-city trips made by Greyhound Canada buses during July and August 2004. The equipment recorded average levels of carbon monoxide (CO) and nitrogen dioxide (NO{sub 2}), as well as concentrations of particulate matter. Bus routes were selected that allowed for an average of 10 hours of total sampling time in a day. Data was recorded on pumps, run times and routes taken. Results indicated that levels of CO in the buses were much lower than the national standard of acceptable levels for CO. Levels of NO{sub 2} were on average lower, but 5 of the 19 recorded values exceeded acceptable levels. Average particulate levels recorded in the buses were considered acceptable, although some of the recorded levels were higher than desirable. It was concluded that further work on in-vehicle levels of NO{sub 2} and particulate matter could be warranted. Although several procedural and equipment problems were encountered, the methods used in the investigation appeared to be valid, and were thought to be suitable for further work on in-vehicle concentrations of pollutants. 21 refs.

  6. Real-world emissions and fuel consumption of diesel buses and trucks in Macao: From on-road measurement to policy implications

    Science.gov (United States)

    Wu, Xiaomeng; Zhang, Shaojun; Wu, Ye; Li, Zhenhua; Zhou, Yu; Fu, Lixin; Hao, Jiming

    2015-11-01

    A total of 13 diesel buses and 12 diesel trucks in Macao were tested using portable emission measurement systems (PEMS) including a SEMTECH-DS for gaseous emissions and a SEMTECH-PPMD for PM2.5. The average emission rates of gaseous pollutants and CO2 are developed with the operating mode defined by the instantaneous vehicle specific power (VSP) and vehicle speed. Both distance-based and fuel mass-based emission factors for gaseous pollutants (e.g., CO, THC and NOX) are further estimated under typical driving conditions. The average distance-based NOX emission of heavy-duty buses (HDBs) is higher than 13 g km-1. Considering the unfavorable conditions for selective reductions catalyst (SCR) systems, such as low-speed driving conditions, more effective technology options (e.g., dedicated natural gas buses and electric buses) should be considered by policy makers in Macao. We identified strong effects of the vehicle size, engine displacement and driving conditions on real-world CO2 emission factors and fuel consumption for diesel vehicles. Therefore, detailed profiles regarding vehicle specifications can reduce the uncertainty in their fleet-average on-road fuel consumption. In addition, strong correlations between relative emission factors and driving conditions indicated by the average speed of generated micro-trips are identified based on a micro-trip method. For example, distance-based emission factors of HDBs will increase by 39% for CO, 29% for THC, 43% for NOX and 26% for CO2 when the average speed decreases from 30 km h-1 to 20 km h-1. The mitigation of on-road emissions from diesel buses and trucks by improving traffic conditions through effective traffic and economic management measures is therefore required. This study demonstrates the important role of PEMS in understanding vehicle emissions and mitigation strategies from science to policy perspectives.

  7. Quantitative characterization of the reliability of simplex buses and stars to compare their benefits in fieldbuses

    International Nuclear Information System (INIS)

    Fieldbuses targeted to highly dependable distributed embedded systems are shifting from bus to star topologies. Surprisingly, despite the efforts into this direction, engineers lack of analyses that quantitatively characterize the system reliability achievable by buses and stars. Thus, to guide engineers in developing adequate bus and star fieldbuses, this work models, quantifies and compares the system reliability provided by simplex buses and stars for the case of the Controller Area Network (CAN). It clarifies how relevant dependability-related aspects affect reliability, refuting some intuitive ideas, and revealing some previously unknown bus and star benefits. - Highlights: • SANs models that quantify the reliability of simplex buses/stars in fieldbuses. • Models cover system relevant dependability-related features abstracted in the literature. • Results refute intuitive ideas about buses and stars and show some unexpected effects. • Models and results can guide the design of reliable simplex bus/stars fieldbuses

  8. Physical and Chemical Characterization of Real-World Particle Number and Mass Emissions from City Buses in Finland.

    Science.gov (United States)

    Pirjola, Liisa; Dittrich, Aleš; Niemi, Jarkko V; Saarikoski, Sanna; Timonen, Hilkka; Kuuluvainen, Heino; Järvinen, Anssi; Kousa, Anu; Rönkkö, Topi; Hillamo, Risto

    2016-01-01

    Exhaust emissions of 23 individual city buses at Euro III, Euro IV and EEV (Enhanced Environmentally Friendly Vehicle) emission levels were measured by the chasing method under real-world conditions at a depot area and on the normal route of bus line 24 in Helsinki. The buses represented different technologies from the viewpoint of engines, exhaust after-treatment systems (ATS) and fuels. Some of the EEV buses were fueled by diesel, diesel-electric, ethanol (RED95) and compressed natural gas (CNG). At the depot area the emission factors were in the range of 0.3-21 × 10(14) # (kg fuel)(-1), 6-40 g (kg fuel)(-1), 0.004-0.88 g (kg fuel)(-1), 0.004-0.56 g (kg fuel)(-1), 0.01-1.2 g (kg fuel)(-1), for particle number (EFN), nitrogen oxides (EFNOx), black carbon (EFBC), organics (EFOrg), and particle mass (EFPM1), respectively. The highest particulate emissions were observed from the Euro III and Euro IV buses and the lowest from the ethanol and CNG-fueled buses, which emitted BC only during acceleration. The organics emitted from the CNG-fueled buses were clearly less oxidized compared to the other bus types. The bus line experiments showed that lowest emissions were obtained from the ethanol-fueled buses whereas large variation existed between individual buses of the same type indicating that the operating conditions by drivers had large effect on the emissions. PMID:26682775

  9. On-road pollutant emission and fuel consumption characteristics of buses in Beijing

    Institute of Scientific and Technical Information of China (English)

    Aijuan Wang; Yunshan Ge; Jianwei Tan; Mingliang Fu; Asad Naeem Shah; Yan Ding; Hong Zhao; Bin Liang

    2011-01-01

    On-road emission and fuel consumption (FC) levels for Euro Ⅲ and Ⅳ buses fueled on diesel and compressed natural gas (CNG)were compared, and emission and FC characteristics of buses were analyzed based on approximately 28,700 groups of instantaneous data obtained in Beijing using a portable emissions measurement system (PEMS). The experimental results revealed that NOx and PM emissions from CNG buses were decreased by 72.0% and 82.3% respectively, compared with Euro Ⅳ diesel buses. Similarly,these emissions were reduced by 75.2% and 96.3% respectively, compared with Euro Ⅲ diesel buses. In addition, CO2, CO, HC,NOx, PM emissions and FC of Euro Ⅳ diesel buses were reduced by 26.4%, 75.2%, 73.6%, 11.4%, 79.1%, and 26.0%, respectively,relative to Euro Ⅲ diesel buses. The CO2, CO, HC, NOx, PM emissions and FC factors all decreased with bus speed increased, while increased as bus acceleration increased. At the same time, the emission/FC rates as well as the emission/FC factors exhibited a strong positive correlation with the vehicle specific power (VSP). They all were the lowest when VSP < 0, and then rapidly increased as VSP increased. Furthermore, both the emission/FC rates and emission/FC factors were the highest at accelerations, higher at cruise speeds,and the lowest at decelerations for non-idling buses. These results can provide a base reference to further estimate bus emission and FC inventories in Beijing.

  10. The Aerodynamics of Heavy Vehicles III : Trucks, Buses and Trains

    CERN Document Server

    Orellano, Alexander

    2016-01-01

    This volume contains papers presented at the International conference “The Aerodynamics of Heavy Vehicles III: Trucks, Buses and Trains” held in Potsdam, Germany, September 12-17, 2010 by Engineering Conferences International (ECI). Leading scientists and engineers from industry, universities and research laboratories, including truck and high-speed train manufacturers and operators were brought together to discuss computer simulation and experimental techniques to be applied for the design of more efficient trucks, buses and high-speed trains in the future.   This conference was the third in the series after Monterey-Pacific Groove in 2002 and Lake Tahoe in 2007.  The presentations address different aspects of train aerodynamics (cross wind effects, underbody flow, tunnel aerodynamics and aeroacoustics, experimental techniques), truck aerodynamics (drag reduction, flow control, experimental and computational techniques) as well as computational fluid dynamics and bluff body, wake and jet flows.

  11. Simulations of the Fuel Economy and Emissions of Hybrid Transit Buses over Planned Local Routes

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming [ORNL; LaClair, Tim J [ORNL; Daw, C Stuart [ORNL; Smith, David E [ORNL; Franzese, Oscar [ORNL

    2014-01-01

    We present simulated fuel economy and emissions city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but trends in the tailpipe (post-aftertreatment) emissions involve more complex interactions that significantly depend on motor size and drive cycle details.

  12. Clean School Bus USA: Tomorrow's Buses for Today's Children

    Science.gov (United States)

    US Environmental Protection Agency, 2010

    2010-01-01

    The U.S. Environmental Protection Agency (EPA) is ensuring that all new buses meet tighter standards developed to reduce diesel emissions and improve safety. Today's new buses are cleaner--60 times cleaner than buses built before 1990--and feature additional emergency exits, improved mirror systems, and pedestrian safety devices. But replacing…

  13. Reducing costs by reducing size

    International Nuclear Information System (INIS)

    The present paper discusses briefly the many factors, including capital cost, which have to be taken into account in determining whether a series of power stations based on a small nuclear plant can be competitive with a series based on traditional large unit sizes giving the guaranteed level of supply. The 320 MWe UK/US Safe Integral Reactor is described as a good example of how the factors discussed can be beneficially incorporated into a design using proven technology. Finally it goes on to illustrate how the overall costs of a generating system can indeed by reduced by use of the 320 MWe Safe Integral Reactor rather than conventional units of around 1200 MWe. (author). 9 figs

  14. Unit Monitors Manchester-Format Data Buses

    Science.gov (United States)

    Amador, Jose J.

    1994-01-01

    Circuit card converts data signals into convenient hexadecimal form for troubleshooting. Bus-monitoring unit converts data signals from Manchester II format used on data bus into hexadecimal format. Monitoring circuit causes hexadecimal words to display on video terminal, where test engineer compares them with hexadecimal records for troubleshooting. Circuit monitors one bus or two buses simultaneously.

  15. Prediction of Conducted Emissions in Satellite Power Buses

    OpenAIRE

    Giordano Spadacini; Flavia Grassi; Diego Bellan; Pignari, Sergio A.; Filippo Marliani

    2015-01-01

    This work reports a modeling methodology for the prediction of conducted emissions (CE) in a wide frequency range (up to 100 MHz), which are generated by dc/dc converters and propagate along the power buses of satellites. In particular, the dc/dc converter seen as a source of CE is represented by a behavioral model, whose parameters can be identified by two unit-level experimental procedures performed in controlled test setups. A simplified multiconductor transmission-line (MTL) model is deve...

  16. Busing: Ground Zero in School Desegregation. A Literature Review With Policy Recommendations.

    Science.gov (United States)

    Hunterton, C. Stanley; And Others

    The contents of this document are organized in six sections. Section one, "Overview," discusses the parameters of the busing controversy. It indicates that the basic issue in the busing debate is racial desegregation in our nation's schools. Section two, "Busing in Perspective," examines the history, scope, and cost of busing; the law and busing;…

  17. Trolley buses in Milan. Zero emission rides through the city; Trolleybusse in Mailand. Voellig emissionsfrei durch die Stadt

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Martin; Boehm, Martin [Vossloh Kiepe GmbH, Duesseldorf (Germany)

    2011-06-15

    Since June 2009, 30 new hybrid trolley buses made by the Van Hool and Vossloh Kiepe consortium have been in service in Milan. Test rides in the Milan city network proved that much energy can be saved by using the energy-storing high-performance supercapacitors. The convincing vehicle concept, featuring a serial arrangement of the driving components, has recently made the city order 15 more trolley buses for Milan and another nine for Parma. (orig.)

  18. Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, K.; Eudy, L.

    2007-03-01

    This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.

  19. COORDINATION OF THE WORK OF BUSES IN CITY ROUTES

    Directory of Open Access Journals (Sweden)

    Fuad DASHDAMIROV

    2013-12-01

    Full Text Available The paper studied the work of bus routes passing through a street. Optimality criterion was chosen for the development of appropriate models of effective work of buses on the land. The paper proposes a new model costing time passengers at bus stops. A method of technique was developed to coordinate the buses running on the combined section of route.

  20. Optimum Network Reconfiguration and DGs Sizing With Allocation Simultaneously by Using Particle Swarm Optimization (PSO)

    OpenAIRE

    M. N. M. Nasir; N. M. Shahrin; M. F. Sulaima; Mohd Hafiz Jali; M. F. Baharom

    2014-01-01

    This paper presents three stages of methodology. The first stage is to identify the switching operation for radial network configuration while observe the power losses and the voltage profile without Distributed Generation (DG). The second stage is based on previous paper which is feeder reconfiguration for loss reduction with DGs. The last stage is sizing and allocation DGs at buses with low voltage profile resulted from the first stage to improve the power losses and voltage profile also co...

  1. Detection of maximum loadability limits and weak buses using Chaotic PSO considering security constraints

    International Nuclear Information System (INIS)

    Highlights: → The unique cost function is derived considering practical Security Constraints. → New innovative formulae of PSO parameters are developed for better performance. → The inclusion and implementation of chaos in PSO technique is original and unique. → Weak buses are identified where FACTS devices can be implemented. → The CPSO technique gives the best performance for all the IEEE standard test systems. - Abstract: In the current research chaotic search is used with the optimization technique for solving non-linear complicated power system problems because Chaos can overcome the local optima problem of optimization technique. Power system problem, more specifically voltage stability, is one of the practical examples of non-linear, complex, convex problems. Smart grid, restructured energy system and socio-economic development fetch various uncertain events in power systems and the level of uncertainty increases to a great extent day by day. In this context, analysis of voltage stability is essential. The efficient method to assess the voltage stability is maximum loadability limit (MLL). MLL problem is formulated as a maximization problem considering practical security constraints (SCs). Detection of weak buses is also important for the analysis of power system stability. Both MLL and weak buses are identified by PSO methods and FACTS devices can be applied to the detected weak buses for the improvement of stability. Three particle swarm optimization (PSO) techniques namely General PSO (GPSO), Adaptive PSO (APSO) and Chaotic PSO (CPSO) are presented for the comparative study with obtaining MLL and weak buses under different SCs. In APSO method, PSO-parameters are made adaptive with the problem and chaos is incorporated in CPSO method to obtain reliable convergence and better performances. All three methods are applied on standard IEEE 14 bus, 30 bus, 57 bus and 118 bus test systems to show their comparative computing effectiveness and

  2. [Energy Conservation and Emissions Reduction Benefits Analysis for Battery Electric Buses Based on Travel Services].

    Science.gov (United States)

    Lin, Xiao-dan; Tian, Liang; Lü, Bin; Yang, Jian-xin

    2015-09-01

    Battery Electric Bus (BEB) has become one of prior options of urban buses for its "zero emission" during the driving stage. However, the environmental performance of electric buses is affected by multi-factors from the point of whole life cycle. In practice, carrying capacity of BEB and power generation structures can both implement evident effects on the energy consumption and pollutants emission of BEB. Therefore, take the above factors into consideration, in this article, Life Cycle Assessment is employed to evaluate the energy conservation and emissions reduction benefits of BEB. Results indicate that, travel service is more reasonable as the functional unit, rather than mileage, since the carrying capacity of BEB is 15% lower than the diesel buses. Moreover, compared with diesel buses, the energy conservation and emissions reduction benefits of battery electric buses are all different due to different regional power structures. Specifically, the energy benefits are 7. 84%, 11. 91%, 26. 90%, 11. 15%, 19. 55% and 20. 31% respectively in Huabei, Huadong, Huazhong, Dongbei, Xibei and Nanfang power structure. From the point of comprehensive emissions reduction benefits, there is no benefit in Huabei power structure, as it depends heavily on coal. But in other areas, the comprehensive emissions reduction benefits of BEB are separately 3. 46%, 26. 81%, 1. 17%, 13. 74% and 17. 48% in Huadong, Huazhong, Dongbei, Xibei and Nanfang. Therefore, it suggests that, enlargement of carrying capacity should be taken as the most prior technology innovation direction for BEB, and the grids power structure should be taken into consideration when the development of BEB is in planning. PMID:26717718

  3. Particle size characterization by ultrasonic attenuation spectra

    Institute of Scientific and Technical Information of China (English)

    Mingxu Su; Minghua Xue; Xiaoshu Cai; Zhitao Shang; Feng Xu

    2008-01-01

    This paper contributes to extracting information from signals of broadband ultrasonic attenuation spectrum for effective utilization in particle size characterization. The single particle scattering model and the coupled-phase model are formulated simultaneously, the relationship between particle size distribution and ultrasonic spectrum is established, and a convergence criterion for calculation is quantified. Demonsa'ation inversion by the optimum regularization factor method is carded out to yield typical numerical results for discussion. With the experimental set-up developed by the Institute of Particle and Two-Phase Flow Measurement (IPTFM) at the University of Shanghai for Science and Technology, sand sediment particle size is measured by attenuation spectrum and analyzed using the above inversion algorithm and theoretical models. To validate the proposed ultrasonic spectrum particle sizing method, results are compared with those obtained by microscopy.

  4. Quality assurance program guidelines for application to and use by manufacturers of rail/guideway vehicles, buses, automatic train control systems, and their major subsystems

    Science.gov (United States)

    Witkin, S. A.

    1976-01-01

    Guidelines are presented for a quality assurance system to be implemented by the manufacturer in support of designing, developing, fabricating, assembling, inspecting, testing, handling, and delivery of equipment being procured for use in public urban mass transit systems. The guidelines apply to this equipment when being procured for: (1) use in revenue service; (2) demonstration of systems that will be revenue producing or used by the public; (3) use as a prototype for follow-on operational/revenue producing equipment procurements; and (4) qualification tests.

  5. Conceptual Design of the TPF-O SC Buses

    Science.gov (United States)

    Purves, Lloyd R.

    2007-01-01

    The Terrestrial Planet Finder - Occulter (TPF-O) mission has two Spacecraft (SC) buses, one for a space telescope and the other for a formation-flying occulter. SC buses typically supply the utilities (support structures, propulsion, attitude control, power, communications, etc) required by the payloads. Unique requirements for the occulter SC bus are to provide the large delta V required for the slewing maneuvers of the occulter, and comunications for formation flying. The TPF-O telescope SC bus shares some key features of the one for the Hubble Space Telescope (HST): both support space telescopes designed to observe in the visible to near infrared range of wavelengths with comparable primary mirror apertures (2.4 m for HST, 2.4 - 4.0 m for TPF-O). However, TPF-O is expected to have a Wide Field Camera (WFC) with a Field of View (FOV) much larger than that of HST. Ths WFC is also expected to provide fine guidance. TPF-O is designed to operate in an orbit around the Sun-Earth Lagrange 2 (SEL2) point. The longer communications range to SEL2 and the large science FOV require higher performance communications than HST. Maintaining a SEL2 orbit requires TPF-O, unlike HST, to have a propulsion system. The velocity required for reachng SEL2 and the limited capabilities of affordable launch vehicles require both TPF-O elements to have compact, low-mass designs. Finally, it is possible that TPF-O may utilize a modular design derived fiom that of HST to allow servicing in the SEL2 orbit.

  6. Optimum Network Reconfiguration and DGs Sizing With Allocation Simultaneously by Using Particle Swarm Optimization (PSO

    Directory of Open Access Journals (Sweden)

    M. N. M. Nasir

    2014-05-01

    Full Text Available This paper presents three stages of methodology. The first stage is to identify the switching operation for radial network configuration while observe the power losses and the voltage profile without Distributed Generation (DG. The second stage is based on previous paper which is feeder reconfiguration for loss reduction with DGs. The last stage is sizing and allocation DGs at buses with low voltage profile resulted from the first stage to improve the power losses and voltage profile also comparing the result with the second stage. The objective of this method proposed is to show that allocation of DGs simultaneously based on low voltage profile can improve network power losses and improvement of voltage profile. The result shows that improvement on network power losses is 54.92% from Distribution Network Reconfiguration (DNR method. All three stages were tested on standards IEEE 33 bus system by using Particle Swarm Optimization (PSO technique in MATLAB software. This method proved that improvement of power losses and voltage profile by switching and DGs allocation method.

  7. Comparative study of the work load between one-man buses and two-man buses.

    Directory of Open Access Journals (Sweden)

    Ueno,Mitsuo

    1985-06-01

    Full Text Available The differences in physiological and safety conditions of one-man buses and two-man buses were examined from the view point of occupational fatigue. This survey consisted of a work load study which included a time study, study of subsidiary behavior, auditory task, memory test, Galvanic Skin Response (GSR and physiological function tests and a self-administered questionnaire which involved items concerning safety and subjective fatigue complaints. The visual and postural restrictions in the one-man bus were greater than in the two-man bus. The mental capacity of the one-man bus drivers was found to be less. Greater mental fatigue and stress were observed in the one-man bus. More subjective fatigue complaints were observed in the one-man bus. More cases of near accidents were observed in the one-man bus. From these results it was concluded that the one-man bus caused bus drivers a greater mental and physical work load.

  8. Evolved star water maser cloud size determined by star size

    CERN Document Server

    Richards, A M S; Gray, M D; Lekht, E E; Mendoza-Torres, J E; Murakawa, K; Rudnitskij, G; Yates, J A

    2012-01-01

    Cool, evolved stars undergo copious mass loss but the details of how the matter is returned to the ISM are still under debate. We investigated the structure and evolution of the wind at 5 to 50 stellar radii from Asymptotic Giant Branch and Red Supergiant stars. 22-GHz water masers around seven evolved stars were imaged using MERLIN, at sub-AU resolution. Each source was observed at between 2 and 7 epochs (several stellar periods). We compared our results with long-term Pushchino single dish monitoring. The 22-GHz emission is located in ~spherical, thick, unevenly filled shells. The outflow velocity doubles between the inner and outer shell limits. Water maser clumps could be matched at successive epochs separated by <2 years for AGB stars, or at least 5 years for RSG. This is much shorter than the decades taken for the wind to cross the maser shell, and comparison with spectral monitoring shows that some features fade and reappear. In 5 sources, most of the matched features brighten or dim in concert from...

  9. Performance of optimised SCR retrofit buses under urban driving and controlled conditions

    Science.gov (United States)

    Carslaw, David C.; Priestman, Max; Williams, Martin L.; Stewart, Gregor B.; Beevers, Sean D.

    2015-03-01

    This work presents the first comprehensive real-world emissions results from urban buses retrofitted with an optimised low-NO2 selective catalytic reduction (SCR) system. The SCRT system combines a CRT (Continuously Regenerating Trap) to reduce particle emissions and SCR to reduce NOx emissions. The optimised low-NO2 SCRT was designed to work under urban conditions where the vehicle exhaust gas temperature is often too low for many SCR systems to work efficiently. The system was extensively tested through on-road and test track measurements using a vehicle emission remote sensing instrument capable of measuring both nitric oxide (NO) and nitrogen dioxide (NO2). Over 700 on-road measurements of the SCRT system were made in London. Compared with identical buses operating under the same conditions fitted with a CRT, NO2 emissions were reduced by 61% and total NOx by 45%. Under test track conditions reductions in NOx of 77% were observed. The test track results do reveal however that compared with an original Euro III bus without a CRT, the SCRT retrofit bus emissions of NO2 are 50% higher. Engine-out and tailpipe measurements of several important engine parameters under test track conditions showed the important effect of SCR inlet temperature on NOx conversion efficiency. Overall, we conclude that retrofitting urban buses to use low-NO2 SCRT systems is an effective method for delivering NOx and NO2 emissions reduction.

  10. Prediction of Conducted Emissions in Satellite Power Buses

    Directory of Open Access Journals (Sweden)

    Giordano Spadacini

    2015-01-01

    Full Text Available This work reports a modeling methodology for the prediction of conducted emissions (CE in a wide frequency range (up to 100 MHz, which are generated by dc/dc converters and propagate along the power buses of satellites. In particular, the dc/dc converter seen as a source of CE is represented by a behavioral model, whose parameters can be identified by two unit-level experimental procedures performed in controlled test setups. A simplified multiconductor transmission-line (MTL model is developed to account for the propagation of CE in shielded bundles of twisted-wire pairs used as power cables. The whole power system is represented by the interconnection of the circuit models of dc/dc converters, cables, and Power Conditioning and Distribution Unit (PCDU. By solving the obtained network, frequency spectra of CE can be predicted. Experimental results are reported to substantiate the accuracy of the proposed unit-level dc/dc converter model and the MTL model of cables. Finally, a system-level test setup composed of three dc/dc converters connected to a PCDU is considered, and predicted CE are compared versus experimental measurements.

  11. An alternative fuel for urban buses-biodiesel blends

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, L.G.; Weber, J.A.; Russell, M.D. [Univ. of Missouri, Columbia, MO (United States)] [and others

    1995-11-01

    Qualitative and quantitative biodiesel fueling performance and operational data have been collected from urban mass transit buses at Bi-State Development Agency in St. Louis Missouri. A total of 10 vehicles were selected for fueling; 5-6V92 TA Detroit Diesel engines have been fueled with a 20/80 biodiesel/diesel fuel blend and 5-6V92 TA Detroit Diesel control vehicles have been fueled on petroleum based low sulfur diesel fuel (LSD). The real-world impact of a biodiesel blend on maintenance, reliability, cost, fuel economy and safety compared to LSD will be presented. In addition, engine exhaust emissions data collected by the University of West Virginia Department of Energy (DOE) sponsored mobile emissions laboratory will be presented. Operational data from Bi-State Development Agency is collected by the University of Missouri and quality control procedures are performed prior to placing the data in the Alternative Fuels Data Center (AFDC). The AFDC is maintained by the National Renewable Energy Laboratory in Golden, Colorado. This effort, which enables transit operators to review a real-world comparison of biodiesel and LSD, has been funded by the National Biodiesel Board with funds provided by the United Soybean Board with national checkoff dollars and the National Renewable Energy Laboratory.

  12. From prototype to product. The development of low emission natural gas- and biogas buses

    Energy Technology Data Exchange (ETDEWEB)

    Ekelund, M. [Strateco Development AB, Haninge (Sweden)

    1998-01-01

    The objective of this report is to show the development of natural gas and bio gas buses and trucks since the termination of the `Co-Nordic GasBus Project`, to which KFB was a major contributor and one of the initiators. Sweden have some 325 heavy duty methane vehicles of which almost 100 are bio gas operated. Scania and Volvo have produced, or have orders for, 500 gas buses to 6 different countries since 1990. The Project objectives were obtained and the significantly reduced emission levels aimed for, were shown. The international bus manufacturing industry followed, and have since shown the same low levels of emissions from gas bus engines. Sweden has taken the lead in the use of bio gas, by operating nearly 100 buses and trucks. Bio gas is still an underestimated fuel when it comes to supply, as it can provide fuel for 50% of the domestic use of diesel oil. Future development need to include control systems for more stable emissions, lower weight cylinders, less costly compressors, cleaning equipment and storage cylinders as well as more fuel efficient engines that can reduce mainly the discharge of CO2, NOx and CH4 further. Societal costs, regardless of who pays, for methane operated buses is still somewhat higher compared with best use of diesel + CRT technology. As commercialization develops, it is expected that the price of the vehicle will be reduced and emissions improved. It is therefore expected that the stake holders costs will be lower then that of diesel technology in the future

  13. Reliability Evaluation Of The City Transport Buses Under Actual Conditions

    Directory of Open Access Journals (Sweden)

    Rymarz Joanna

    2015-12-01

    Full Text Available The purpose of this paper was to present a reliability comparison of two types of city transport buses. Case study on the example of the well-known brands of city buses: Solaris Urbino 12 and Mercedes-Benz 628 Conecto L used at Municipal Transport Company in Lublin was presented in details. A reliability index for the most failure parts and complex systems for the period of time failures was determined. The analysis covered damages of the following systems: engine, electrical system, pneumatic system, brake system, driving system, central heating and air-conditioning and doors. Reliability was analyzed based on Weibull model. It has been demonstrated, that during the operation significant reliability differences occur between the buses produced nowadays.

  14. Diesel vs. compressed natural gas for school buses: a cost-effectiveness evaluation of alternative fuels

    International Nuclear Information System (INIS)

    Reducing emissions from school buses is a priority for both state and federal regulators. Two popular alternative technologies to conventional diesel (CD) are emission controlled diesel (ECD), defined here to be diesel buses equipped with continuously regenerating particle filters, and engines fueled by compressed natural gas (CNG). This paper uses a previously published model to quantify the impact of particulate matter (PM), oxides of nitrogen (NOx), and sulfur dioxide (SO2) emissions on population exposure to ozone and to primary and secondary PM, and to quantify the resulting health damages, expressed in terms of lost quality adjusted life years (QALYs). Resource costs include damages from greenhouse gas-induced climate change, vehicle procurement, infrastructure development, and operations. I find that ECD and CNG produce very similar reductions in health damages compared to CD, although CNG has a modest edge because it may have lower NOx emissions. However, ECD is far more cost effective ($400,000-900,000 cost per QALY saved) than CNG (around $4 million per QALY saved). The results are uncertain because the model used makes a series of simplifying assumptions and because emissions data and cost data for school buses are very limited

  15. CNG/diesel buses for Texas school districts

    International Nuclear Information System (INIS)

    At the present time, the preponderance of trucks, buses and other heavy duty vehicles are powered by diesel engines. The reasons for the change from gasoline to diesel engines are all basically economic, due to the longer life and lower operating costs of diesel engines, as compared to gasoline engines. This provides a compelling reason to continue to use these engines, even if powered by fuel other than diesel. A major strategy within the industry has been the various attempts to adapt diesel engines to alternative fuels. These conversions have been largely to either methanol or natural gas, with propane joining the race just recently. This strategy takes advantage of the remaining life of existing vehicles by converting engines rather than purchasing a new engine (and/or vehicle) designed for and dedicated to an alternate fuel. Although diesel engines have been converted to run on natural gas, there are substantial challenges that must be met. The following describes some of the technical approaches being used for diesel engine conversions

  16. Assessing Children's Exposure to Ultrafine Particles and Other Air Pollutants in School Buses and at Schools

    OpenAIRE

    Zhang, Qunfang

    2012-01-01

    Increasing evidence has demonstrated toxic effects of ultrafine particles (UFPs, diameter < 100 nm). Children are particularly at risk due to their immature respiratory systems and greater breathing rates per body weight. This study aims to assess children's exposure to UFPs and other air pollutants in school buses and at schools. 24 school buses were employed to represent commonly used school buses in the United States. UFPs and other air pollutants in and around school buses were measured w...

  17. Intermediate transport in Southeast Asia. [Carts, cycles, mini-buses

    Energy Technology Data Exchange (ETDEWEB)

    Meier, A.K.

    1977-06-01

    Traffic flows through the streets of Southeast Asian countries even though they are used for almost all aspects of human and animal existence. The carts, bicycles, tricycles, and motorcycles, motorized three-wheelers, mini-buses are the so-called intermediate-transport vehicles. It is upon this group of vehicles that a culture--constrained by its own unique economic, environmental, and technological factors--exerts its influence most directly toward the solution of the transport problem. Transportation fills more service roles in Southeast Asian cities than in Western cities. Communication facilities such as telephones and postal services are notoriously unreliable. The personal encounter is all important in social and business interactions in Southeast Asia. Each of the transport modes is examined in view of design and use in a number of specific cultural settings for the countries in Southeast Asia. Present use of intermediate transport in developed countries is discussed briefly, and its further development predicted--pointing out the health and conservation advantages. (MCW)

  18. Cost Effectiveness Analysis of Quasi-In-Motion Wireless Power Transfer for Plug-In Hybrid Electric Transit Buses from Fleet Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lijuan; Gonder, Jeff; Brooker, Aaron; Meintz, Andrew; Konan, Arnaud; Markel, Tony

    2016-05-16

    This study evaluated the costs and benefits associated with the use of stationary-wireless-power-transfer-enabled plug-in hybrid electric buses and determined the cost effectiveness relative to conventional buses and hybrid electric buses. A factorial design was performed over a number of different battery sizes, charging power levels, and f bus stop charging stations. The net present costs were calculated for each vehicle design and provided the basis for design evaluation. In all cases, given the assumed economic conditions, the conventional bus achieved the lowest net present cost while the optimal plug-in hybrid electric bus scenario beat out the hybrid electric comparison scenario. The parameter sensitivity was also investigated under favorable and unfavorable market penetration assumptions.

  19. Active screening of magnetic field near power stations generator buses

    Directory of Open Access Journals (Sweden)

    B.I. Kuznetsov

    2013-12-01

    Full Text Available An experimental study technique for a prototyping system of active screening of power-frequency magnetic field distortions near power station generator buses via controllable magnetic field sources is presented. Results of experimental research on a proto-typing active screening system with different control algorithms are given.

  20. Children's Awareness of Watergate, Busing, Energy, Inflation, and the Bicentennial

    Science.gov (United States)

    Duffey, Robert V.; Weaver, V. Phillips

    1977-01-01

    A research study assessed the awareness of a group of fourth through sixth graders about current events, including busing, energy, inflation, and the Bicentennial. Awareness was found to differ significantly according to location of school and grade in school. Causes for the differences may include life style, curricular emphases, and teacher…

  1. Conceptualization of relative size by honeybees

    Directory of Open Access Journals (Sweden)

    Aurore eAvargues-Weber

    2014-03-01

    Full Text Available The ability to process visual information using relational rules allows for decisions independent of the specific physical attributes of individual stimuli. Until recently, the manipulation of relational concepts was considered as a prerogative of large mammalian brains. Here we show that individual free flying honeybees can learn to use size relationship rules to choose either the larger or smaller stimulus as the correct solution in a given context, and subsequently apply the learnt rule to novel colors and shapes providing that there is sufficient input to the long wavelength (green photoreceptor channel. Our results add a novel, size-based conceptual rule to the set of relational concepts that honeybees have been shown to master and underline the value of bees as an animal model for studying the emergence of conceptualization abilities.

  2. Transmission Loss Allocation Based on Buses Injected Currents

    Directory of Open Access Journals (Sweden)

    R.Aazami

    2011-09-01

    Full Text Available In this paper, a new method is proposed to allocate transmission loss in pool-based electricity markets. This method is based on using the impedance matrix of the network and the admittance equivalent circuit seen from the network buses. After performing load flow equations, the losses of each bus are calculated using the impedance matrix of the network and the reduced admittance matrix and the injected currents from each bus. These losses are properly and fairly shared between network buses for fair loss allocation in proportion to the percent of penetration the currents of each bus. Furthermore, using partial derivatives of the active power losses with respect to the bus currents’ coefficients, a sensitivity analysis has been done for proving the fairness of the proposed method. In addition to its simplicity, the suggested method assigns the losses properly and fairly between the buses. Finally, this method has been tested on a benchmark IEEE 14-bus network, and the results are compared with other existing methods.

  3. Operational integrity using field buses; Integridade operacional utilizando barramentos de campo

    Energy Technology Data Exchange (ETDEWEB)

    Hennig, Carlos Henrique [Coester Automacao S.A., Sao Leopoldo, RS (Brazil)

    2004-07-01

    The device information is collected using standardized Filed Buses with high data transmission capacity, which allows the analysis of his operational status in real time. The quantity of information generated by the devices for the maintenance area is increasing and this data quantity transferred through the field bus should not interfere in the network performance to the point of degrade his control function. In this way, is presented a technique that can be used in different protocols, which allow sending of maintenance data using a small band of the communication channel. Operational integrity can be achieved using predictive maintenance techniques based on the collected data. (author)

  4. Analysis of the cost of hydrogen infrastructure for buses in London

    Science.gov (United States)

    Shayegan, S.; Hart, D.; Pearson, P.; Joffe, D.

    The use of hydrogen (H 2) as transport fuel is often said to suffer from the 'chicken and egg' problem: vehicles that depend on H 2 cannot go on the roads due to the lack of an adequate infrastructure, and the almost non-existent fleet of H 2 vehicles on the roads makes it economically unsound to build a H 2 infrastructure. Although both hydrogen vehicles (fuel cell and internal combustion engine) and the related infrastructure have been (and are being) developed and some are commercially available, cost is seen as a major barrier. With today's technologies, H 2 only becomes competitive with petrol and diesel when produced at large quantities, suitable for supplying e.g. thousands of H 2 buses. The question is, how might this point be reached, and are there least cost infrastructural pathways to reach it. This paper tries to address the latter question, using the early development of a H 2 infrastructure for buses in London as a case study. The paper presents some of the analyses and results from a Ph.D. project (in progress) being undertaken at Imperial College London, funded by EPSRC (Grant GR/R50790/01). The results presented here illustrate that cost of hydrogen production and delivery vary mainly with levels of hydrogen demand and delivery distances, as well as other logistic criteria; least cost production-delivery pathways have been identified for various hydrogen demand scenarios and refuelling station set-ups. Another important conclusion is that the pattern of converting a group of refuelling stations to hydrogen (e.g. a group of refuelling stations for buses in London) has a significant effect on the unit cost of hydrogen.

  5. To Evaluate Zero Emission Propulsion and Support Technology for Transit Buses

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Chandler; Leslie Eudy

    2006-11-01

    This report provides evaluation results for prototype fuel cell transit buses operating at Santa Clara Valley Transportation Authority (VTA) in San Jose, California, in partnership with the San Mateo County Transit District in San Carlos, California. VTA has been operating three fuel cell transit buses in extra revenue service since February 28, 2005. This report provides descriptions of the equipment used, early experiences, and evaluation results from the operation of the buses and the supporting hydrogen infrastructure from March 2005 through July 2006.

  6. Tailoring Porosity of Colloidal Boehmite Sol by Controlling Crystallite Size

    Energy Technology Data Exchange (ETDEWEB)

    Park, Myung Chul; Lee, Sung Reol; Kim, Hark; Park, In; Choy, Jin Ho [Ewha Womans University, Seoul (Korea, Republic of)

    2012-06-15

    Boehmite sols have been prepared by crystallization of amorphous aluminum hydroxide gel obtained by hydrolysis and peptization of aluminum using acetic acid. The size of the boehmite crystallites could be controlled by Al molar concentration in amorphous gel by means of controlling grain growth at nucleation stage. The size of boehmite increases as a function of Al molar concentration. With increasing boehmite crystallite size, the d{sub (020)} spacing and the specific surface area decreases, whereas the pore volume increases along with pore size. Especially, the pore size of the boehmite sol particles is comparable to the crystallite size along the b axis, suggesting that the fibril thickness along the b axis among the crystallite dimensions of the boehmite contributes to the pore size. Therefore, the physical properties of boehmite sols can be determined by the crystallite size controlled as a function of initial Al concentration

  7. A vehicle-specific power approach to speed- and facility-specific emissions estimates for diesel transit buses.

    Science.gov (United States)

    Zhai, Haibo; Frey, H Christopher; Rouphail, Nagui M

    2008-11-01

    Emissions during a trip often depend on transient vehicle dynamics that influence the instantaneous engine load. Vehicle specific power (VSP) is a proxy variable for engine load that has been shown to be highly correlated with emissions. This study estimates roadway link average emission rates for diesel-fueled transit buses based on link mean speeds, using newly defined VSP modes from data gathered by a portable emissions monitoring system. Speed profiles were categorized by facility type and mean travel speed, and stratified into discrete VSP modes. VSP modal average emission rates and the time spent in the corresponding VSP modes were then used to make aggregate estimates of total and average emission rates for a road link. The average emission rates were sensitive to link mean speed, but not to facility type. A recommendation is made regarding the implementation of link average emission rates in conjunction with transportation models for the purpose of estimating regional emissions for diesel transit buses. PMID:19031891

  8. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2015

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, Leslie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Post, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gikakis, Christina [Federal Transit Administration, Washington, DC (United States)

    2015-12-11

    This report, published annually, summarizes the progress of fuel cell electric bus (FCEB) development in the United States and discusses the achievements and challenges of introducing fuel cell propulsion in transit. Various stakeholders, including FCEB developers, transit agencies, and system integrators, have expressed the value of this annual status report, which provides a summary of results from evaluations performed by the National Renewable Energy Laboratory. The annual status report tracks the progress of the FCEB industry toward meeting technical targets, documents the lessons learned, and discusses the path forward for commercial viability of fuel cell technology for transit buses. The 2015 summary results primarily focus on the most recent year for each demonstration, from August 2014 through July 2015. The results for these buses account for more than 1,045,000 miles traveled and 83,000 hours of fuel cell power system operation. The primary results presented in the report are from two demonstrations of fuel-cell-dominant bus designs: the Zero Emission Bay Area Demonstration Group led by Alameda-Contra Costa Transit District (AC Transit) in California and the American Fuel Cell Bus Project at SunLine Transit Agency in California.

  9. Itinerant vending of medicines inside buses in Nigeria: vending strategies, dominant themes and medicine-related information provided

    OpenAIRE

    Yusuff KB; Wassi Sanni A

    2011-01-01

    Objective To determine vending strategies and marketing themes employed by itinerant bus vendors, and assess the accuracy and completeness of information provided on medicines being sold in an urban setting in Nigeria. Methods Cross-sectional study and content analysis of itinerant vending of medicines inside buses recorded with a mobile telephone on purposively selected routes in a mega city with an estimated 18 million residents in southwestern Nigeria over a 2-month period. Two coders inde...

  10. Development of a driving cycle for intra-city buses in Chennai, India

    Science.gov (United States)

    Nesamani, K. S.; Subramanian, K. P.

    2011-10-01

    In India the emissions rate and fuel consumption of intra-city buses are estimated using the European driving cycles, which don't represent Indian driving conditions and in-use operation of vehicles. This leads to underestimation or overestimation of emissions and fuel consumption. In this context, this paper offers some insight into the driving characteristics of intra-city buses using a Global Positioning System. The study has revealed that irrespective of road type and time of travel, a higher percentage of time is spent in idle mode. This is primarily due to alighting and boarding of passengers at regular intervals and fixed delays caused by traffic lights. More than 90 percent of trips have an average speed of less than 30 km h -1. This study has also developed an intra-city bus driving cycle for Chennai and compared it with some well-known international driving cycles. It has revealed that Chennai has unique driving characteristics and, therefore, it may not be appropriate to adopt a driving cycle of another country or city.

  11. Towards colloidal size control by precipitation

    OpenAIRE

    Lebouille, J.G.J.L.

    2014-01-01

    Many active ingredients like drugs, preservatives and vitamins are hydrophobic. In most applications for food and pharma, however, they need to be functional in aqueous environments. In order to facilitate their usage in aqueous environments one needs a way to enable the dispersion of hydrophobic compounds into submicron particles in water in a controlled manner. We investigated the stabilization by surfactants and encapsulation into micelles of hydrophobic compounds using the nanoprecipitati...

  12. Buses and Boards Making the right choice

    CERN Document Server

    Gipper, Jerry

    2009-01-01

    From motherboard to backplane to blade based computer systems, the choices are numerous. This paper will cover the markets and trends within those markets that influence decisions made by board suppliers. Discussion will focus on the various form factors, the development and evolution of industry standards, and the consortia that support and develop these standards, including VITA, PICMG, and others. This paper will conclude with suggestions for choosing the right form factor for your application.

  13. The uses of biodiesel in buses

    International Nuclear Information System (INIS)

    In November 2001 in Naukseni, Valmiera district the biodiesel - methyl ester of rapeseed oil (RME) - plant first in Latvia and in all Baltic States began to work. The production capacity of the plant is 2500 t of biodiesel per year. In the summer and autumn period of the last year the first experiment using 100% RME on one city bus line was carried out. The bus Ikarus-280 in total turned 30700 km consuming 11 tons or 12600 litres of biodiesel. The fuel consumption with biodiesel was 0.9 kg/h (14.2%) or 3.01/100 km higher as with fossil diesel fuel. The engine power and the driving speed on the line were practically unchanged in spite that the heat capacity of biodiesel is lower than of ordinary diesel fuel (according 37.1 l and 42.1 MJ/kg). Using biodiesel the toxicity of the exhaust gases dropped down very essentially. It was controlled regularly by measuring the absorption coefficient and smokiness. At the end of second month of the experiment the absorption coefficient was 2.09 m-1 and 47.8%. This shows that by the influence of biodiesel the compression chambers of the engine clean from burnt parts and the combustion process most completely thanks to the oxygen content in the biodiesel (authors)

  14. Estimativa dos poluentes emitidos pelos ônibus e microônibus de Campo Grande/MS, empregando como combustível diesel, biodiesel ou gás natural Estimation of the atmospheric pollutants emitted in Campo Grande/MS, by buses and minibuses which employ diesel, biodiesel or natural gas as fuels

    Directory of Open Access Journals (Sweden)

    Glauco Rodrigo Kozerski

    2006-06-01

    Full Text Available É apresentada uma estimativa do total de poluentes emitidos mensalmente por ônibus e microônibus em Campo Grande (MS, empregando-se diesel, biodiesel ou gás natural como combustíveis. O método "bottom-up" foi utilizado para os cálculos das emissões gasosas. Os estudos realizados permitem inferir que a substituição do diesel pelo biodiesel resultaria em diminuição das emissões de poluentes, geração de novos postos de empregos a partir de atividades agrícolas e industriais, e a diminuição na importação de petróleo, já que o Brasil importa petróleo, basicamente, para suprir a demanda de diesel.The present work deals with the estimation of the atmospheric pollutants emitted monthly in Campo Grande/MS by buses and minibuses, which employ diesel, biodiesel or natural gas as fuels. For the gaseous emissions calculations was used a "bottom-up" technique. The results obtained show that the substitution of diesel by biodiesel would diminish the emissions of pollutants, create novel job opportunities from agricultural and industrial activities, and reduce the Brazilian petroleum imports, which are basically used for meeting the demands in diesel.

  15. Bay Area Transit Agencies Propel Fuel Cell Buses Toward Commercialization (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2010-07-01

    This fact sheet describes the Zero Emission Bay Area (ZEBA) demonstration of the next generation of fuel cells buses. Several transit agencies in the San Francisco Bay Area are participating in demonstrating the largest single fleet of fuel cell buses in the United States.

  16. The Bus Stops Here: The Case for Biodiesel in School Buses.

    Science.gov (United States)

    Rao, Steven T.

    2002-01-01

    Suggests that diesel exhaust from most of the nation's school buses may be hazardous to children's health. Documents studies on the nature and potential magnitude of the risk to children and proposes replacing petroleum diesel with biodiesel as the fuel for school buses. Presents the merits and practicality of switching to biodiesel as a healthier…

  17. Using Task Clarification, Goal Setting, and Feedback to Decrease Table Busing Times in a Franchise Pizza Restaurant

    Science.gov (United States)

    Amigo, Seth; Smith, Andrew; Ludwig, Timothy

    2008-01-01

    The current study investigated the effects of task-clarification, and manager verbal and graphic feedback on employee busing times at a pizza restaurant. Using an ABC design, task-clarification was provided in a memo, which described the process, priority, and goal time of busing. The busing time decreased slightly, from an average of 315 seconds…

  18. Size Controlled Synthesis of Starch Nanoparticles by a Microemulsion Method

    Directory of Open Access Journals (Sweden)

    Suk Fun Chin

    2014-01-01

    Full Text Available Controllable particles sizes of starch nanoparticles were synthesized via a precipitation in water-in-oil microemulsion approach. Microemulsion method offers the advantages of ultralow interfacial tension, large interfacial area, and being thermodynamically stable and affords monodispersed nanoparticles. The synthesis parameters such as stirring rates, ratios of oil/cosurfactant, oil phases, cosurfactants, and ratios of water/oil were found to affect the mean particle size of starch nanoparticles. Starch nanoparticles with mean particles sizes of 109 nm were synthesized by direct nanoprecipitation method, whereas by using precipitation in microemulsion approach, starch nanoparticles with smaller mean particles sizes of 83 nm were obtained.

  19. Size-selected copper oxide nanoparticles synthesized by laser ablation

    International Nuclear Information System (INIS)

    Size-tuned copper oxide nanoparticles with sizes of 9, 12, and 15 nm were fabricated by laser ablation and on-line size selection using a differential mobility analyzer at a gas pressure of 666 Pa. The dependence of the particle properties on the in situ annealing temperatures and selection sizes was investigated. The crystalline phases of the nanoparticles fabricated at temperatures below 973 K were assigned to monoclinic cupric oxide (CuO) which converted into cubic cuprous oxide (Cu2O) when the annealing temperature was above 1,173 K. This indicates that the crystalline phases can be easily controlled by changing the annealing temperature. TEM images confirmed that well-crystallized and well-dispersed CuO and Cu2O nanoparticles with narrow size distributions were obtained using this method. This fabrication process is useful and promising for the future investigation of the intrinsic size-dependent properties of CuO and Cu2O.

  20. A case study of real-world tailpipe emissions for school buses using a 20% biodiesel blend.

    Science.gov (United States)

    Mazzoleni, Claudio; Kuhns, Hampden D; Moosmüller, Hans; Witt, Jay; Nussbaum, Nicholas J; Oliver Chang, M-C; Parthasarathy, Gayathri; Nathagoundenpalayam, Suresh Kumar K; Nikolich, George; Watson, John G

    2007-10-15

    Numerous laboratory studies report carbon monoxide, hydrocarbon, and particulate matter emission reductions with a slight nitrogen oxides emission increase from engines operating with biodiesel and biodiesel blends as compared to using petroleum diesel. We conducted a field study on a fleet of school buses to evaluate the effects of biodiesel use on gaseous and particulate matter fuel-based emission factors under real-world conditions. The field experiment was carried out in two phases during winter 2004. In January (phase I), emissions from approximately 200 school buses operating on petroleum diesel were measured. Immediately after the end of the first phase measurement period, the buses were switched to a 20% biodiesel blend. Emission factors were measured again in March 2004 (phase II) and compared with the January emission factors. To measure gaseous emission factors we used a commercial gaseous remote sensor. Particulate matter emission factors were determined with a combination of the gaseous remote sensor, a Lidar (light detection and ranging), and transmissometer system developed at the Desert Research Institute of Reno, NV, U.S.A. Particulate matter emissions from school buses significantly increased (up to a factor of 1.8) after the switch from petroleum diesel to a 20% biodiesel blend. The fuel used during this campaign was provided by a local distributor and was independently analyzed at the end of the on-road experiment. The analysis found high concentrations of free glycerin and reduced flash points in the B 100 parent fuel. Both measures indicate improper separation and processing of the biodiesel product during production. The biodiesel fuels used in the school buses were not in compliance with the U.S.A. ASTM D6751 biodiesel standard that was finalized in December of 2001. The U.S.A. National Biodiesel Board has formed a voluntary National Biodiesel Accreditation Program for producers and marketers of biodiesel to ensure product quality and

  1. Txatarra: vivienda transitoria con buses de transporte público

    Directory of Open Access Journals (Sweden)

    Juan Pablo Arenas Vargas

    2011-07-01

    Full Text Available El presente análisis del proyecto Casa Linda parte de una exploración conceptual en torno a un hábitat sostenible, mediante la generación de un tipo de vivienda transitoria que reutiliza buses de transporte público destinados a ser reducidos a chatarra. La necesidad de replantear la labor de configurar espacios con materiales y formas predeterminados llevó a los autores a comprender cómo resultan insuficientes los medios tradicionales de construcción, en los que se acostumbra emplear materias primas en presentaciones estandarizadas y con acabados predefinidos que se adaptan a los requerimientos y necesidades del proyecto. Enfrentar el proyecto a partir del reciclaje de materiales y objetos (chatarra, de diversas dimensiones y en variadas condiciones, generó un proceso cuya característica principal es la imposibilidad de anticipar con exactitud los procesos constructivos y los acabados finales.

  2. Resistojet control and power for high frequency ac buses

    Science.gov (United States)

    Gruber, Robert P.

    1987-01-01

    Resistojets are operational on many geosynchronous communication satellites which all use dc power buses. Multipropellant resistojets were selected for the Initial Operating Capability (IOC) Space Station which will supply 208 V, 20 kHz power. This paper discusses resistojet heater temperature controllers and passive power regulation methods for ac power systems. A simple passive power regulation method suitable for use with regulated sinusoidal or square wave power was designed and tested using the Space Station multipropellant resistojet. The breadboard delivered 20 kHz power to the resistojet heater. Cold start surge current limiting, a power efficiency of 95 percent, and power regulation of better than 2 percent were demonstrated with a two component, 500 W breadboard power controller having a mass of 0.6 kg.

  3. Cell size checkpoint control by the retinoblastoma tumor suppressor pathway.

    Directory of Open Access Journals (Sweden)

    Su-Chiung Fang

    2006-10-01

    Full Text Available Size control is essential for all proliferating cells, and is thought to be regulated by checkpoints that couple cell size to cell cycle progression. The aberrant cell-size phenotypes caused by mutations in the retinoblastoma (RB tumor suppressor pathway are consistent with a role in size checkpoint control, but indirect effects on size caused by altered cell cycle kinetics are difficult to rule out. The multiple fission cell cycle of the unicellular alga Chlamydomonas reinhardtii uncouples growth from division, allowing direct assessment of the relationship between size phenotypes and checkpoint function. Mutations in the C. reinhardtii RB homolog encoded by MAT3 cause supernumerous cell divisions and small cells, suggesting a role for MAT3 in size control. We identified suppressors of an mat3 null allele that had recessive mutations in DP1 or dominant mutations in E2F1, loci encoding homologs of a heterodimeric transcription factor that is targeted by RB-related proteins. Significantly, we determined that the dp1 and e2f1 phenotypes were caused by defects in size checkpoint control and were not due to a lengthened cell cycle. Despite their cell division defects, mat3, dp1, and e2f1 mutants showed almost no changes in periodic transcription of genes induced during S phase and mitosis, many of which are conserved targets of the RB pathway. Conversely, we found that regulation of cell size was unaffected when S phase and mitotic transcription were inhibited. Our data provide direct evidence that the RB pathway mediates cell size checkpoint control and suggest that such control is not directly coupled to the magnitude of periodic cell cycle transcription.

  4. Fast Charging Battery Buses for the Electrification of Urban Public Transport—A Feasibility Study Focusing on Charging Infrastructure and Energy Storage Requirements

    Directory of Open Access Journals (Sweden)

    Matthias Rogge

    2015-05-01

    Full Text Available The electrification of public transport bus networks can be carried out utilizing different technological solutions, like trolley, battery or fuel cell buses. The purpose of this paper is to analyze how and to what extent existing bus networks can be electrified with fast charging battery buses. The so called opportunity chargers use mainly the regular dwell time at the stops to charge their batteries. This results in a strong linkage between the vehicle scheduling and the infrastructure planning. The analysis is based on real-world data of the bus network in Muenster, a mid-sized city in Germany. The outcomes underline the necessity to focus on entire vehicle schedules instead on individual trips. The tradeoff between required battery capacity and charging power is explained in detail. Furthermore, the impact on the electricity grid is discussed based on the load profiles of a selected charging station and a combined load profile of the entire network.

  5. Selective follicular targeting by modification of the particle sizes.

    Science.gov (United States)

    Patzelt, Alexa; Richter, Heike; Knorr, Fanny; Schäfer, Ulrich; Lehr, Claus-Michael; Dähne, Lars; Sterry, Wolfram; Lademann, Juergen

    2011-02-28

    Hair follicles represent interesting target sites for topically applied substances such as topical vaccinations or agents used in the field of regenerative medicine. In recent years, it could be shown that particles penetrate very effectively into the hair follicles. In the present study, the influence of particle size on the follicular penetration depths was examined. The penetration depths of two different types of particles sized 122 to 1000 nm were determined in vitro on porcine skin. The results revealed that the particles of medium size (643 and 646 nm, respectively) penetrated deeper into the porcine hair follicles than smaller or larger particles. It was concluded that by varying the particle size, different sites within the porcine hair follicle can be targeted selectively. For the human terminal hair follicle, the situation can be expected to be similar due to a similar size ratio of the hair follicles. PMID:21087645

  6. Mining the Shirt Sizes for Indian Men by Clustered Classification

    Directory of Open Access Journals (Sweden)

    Kumaravel Appavoo

    2012-06-01

    Full Text Available In garment production engineering, sizing system plays an important role for manufacturing of clothing. The standards for defining the size label are a critical issue. Locating the right garment size for a customer depends on the label as an interface. In this research work intend to approach that it could be used for developing sizing systems by data mining techniques applied to Indian anthropometric dataset. We propose a new approach of two-stage data mining procedure for labelling the shirt types exclusively for Indian men. In the first stage , clustering technique applied on the original dataset, to categorise the size labels. Then these clusters are used for supervised learning in the second stage for classification. A sizing system classifies a specific population into homogeneous subgroups based on some key body dimensions. The space with these dimensions gives raise to complexity for finding uniform standards. This enables us to have an interface as a communication tool among manufacturers, retailers and consumers. This sizing system is developed for the men’s age ranges between 25 and 66 years. Main attribute happens to be the chest size as clearly visible in the data set. We have obtained classifications for men’s shirt attributes based on clustering techniques.

  7. Humans are not fooled by size illusions in attractiveness judgements.

    Science.gov (United States)

    Bateson, Melissa; Tovée, Martin J; George, Hannah R; Gouws, Anton; Cornelissen, Piers L

    2014-03-01

    Could signallers use size contrast illusions to dishonestly exaggerate their attractiveness to potential mates? Using composite photographs of women from three body mass index (BMI) categories designed to simulate small groups, we show that target women of medium size are judged as thinner when surrounded by larger women than when surrounded by thinner women. However, attractiveness judgements of the same target women were unaffected by this illusory change in BMI, despite small true differences in the BMIs of the target women themselves producing strong effects on attractiveness. Thus, in the context of mate choice decisions, the honesty of female body size as a signal of mate quality appears to have been maintained by the evolution of assessment strategies that are immune to size contrast illusions. Our results suggest that receiver psychology is more flexible than previously assumed, and that illusions are unlikely to drive the evolution of exploitative neighbour choice in human sexual displays. PMID:24719551

  8. Humans are not fooled by size illusions in attractiveness judgements☆

    Science.gov (United States)

    Bateson, Melissa; Tovée, Martin J.; George, Hannah R.; Gouws, Anton; Cornelissen, Piers L.

    2014-01-01

    Could signallers use size contrast illusions to dishonestly exaggerate their attractiveness to potential mates? Using composite photographs of women from three body mass index (BMI) categories designed to simulate small groups, we show that target women of medium size are judged as thinner when surrounded by larger women than when surrounded by thinner women. However, attractiveness judgements of the same target women were unaffected by this illusory change in BMI, despite small true differences in the BMIs of the target women themselves producing strong effects on attractiveness. Thus, in the context of mate choice decisions, the honesty of female body size as a signal of mate quality appears to have been maintained by the evolution of assessment strategies that are immune to size contrast illusions. Our results suggest that receiver psychology is more flexible than previously assumed, and that illusions are unlikely to drive the evolution of exploitative neighbour choice in human sexual displays. PMID:24719551

  9. Nanometer sized structures grown by pulsed laser deposition

    KAUST Repository

    ElZein, Basma

    2015-10-01

    Nanometer sized materials can be produced by exposing a target to a laser source to remove material from the target and deposit the removed material onto a surface of a substrate to grow a thin film in a vacuum chamber

  10. Mosquito Consumption by Insectivorous Bats: Does Size Matter?

    OpenAIRE

    Gonsalves, Leroy; Bicknell, Brian; Law, Brad; Webb, Cameron; Monamy, Vaughan

    2013-01-01

    Insectivorous bats have often been touted as biological control for mosquito populations. However, mosquitoes generally represent only a small proportion of bat diet. Given the small size of mosquitoes, restrictions imposed on prey detectability by low frequency echolocation, and variable field metabolic rates (FMR), mosquitoes may not be available to or profitable for all bats. This study investigated whether consumption of mosquitoes was influenced by bat size, which is negatively correlate...

  11. Sizing of IGSCCs by crack-tip diffraction technique

    International Nuclear Information System (INIS)

    The Electric Power Research Institute, through its Non-Destructive Evaluation Center, conducted a round-robin sizing exercise to test the accuracy of the size estimates of inter-granular stress corrosion cracks (IGSCCs) made by inspectors using manual ultrasonic techniques. The results show the following: the number of teams doing an adequate job is much lower than anticipated; the range of performance from best to worst is very large; the advanced techniques provide verification that the crack-tip diffraction sizing approach is the most viable method; the influence of the ultrasonic measurement uncertainty to the flaw evaluation results must be assessed on case-by-case basis; and corrective actions are needed. The recommended corrective actions are: develop and implement a training program for people who size IGSCC; implement a qualification program that requires all people who perform sizing operations to demonstrate their capability prior to making field measurements; and accelerate completion, evaluation, and deployment of advanced systems. The present program is the result of the accelerated development of the crack-tip diffraction sizing technique. The immediate objectives of this program were: 1) to develop computerized techniques that result in being able to make reliable and reproducible estimates of crack depth using the crack-tip diffraction technique, and 2) to prepare an off-line service capability for sizing IGSCCs for the utilities

  12. Model catalysis by size-selected cluster deposition

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Scott [Univ. of Utah, Salt Lake City, UT (United States)

    2015-11-20

    This report summarizes the accomplishments during the last four years of the subject grant. Results are presented for experiments in which size-selected model catalysts were studied under surface science and aqueous electrochemical conditions. Strong effects of cluster size were found, and by correlating the size effects with size-dependent physical properties of the samples measured by surface science methods, it was possible to deduce mechanistic insights, such as the factors that control the rate-limiting step in the reactions. Results are presented for CO oxidation, CO binding energetics and geometries, and electronic effects under surface science conditions, and for the electrochemical oxygen reduction reaction, ethanol oxidation reaction, and for oxidation of carbon by water.

  13. Performance study about biodiesel impact on buses engines using dynamometer tests and fleet consumption data

    International Nuclear Information System (INIS)

    Highlights: ► Driving cycle affects the fuel impacts on engine emissions and performance. ► Incorporation of biodiesel can improve efficiency for some engine regimes. ► Biodiesel oxygen content probably increases combustion efficiency in engine. ► The consumption of the fleet agrees with the dynamometer results. ► NOx emissions are very sensitive to engine operating conditions. - Abstract: The problem of reducing harmful emissions, mainly particulate matter (PM) and nitrogen oxides (NOxs) originated in compression ignition combustion engines, and also the mandatory intention of lowering the CO2 impacts of road transportation define the need to improve our knowledge on biodiesel use in engines. A 6 in line cylinders Volvo engine was submitted to a 100 min cycle with 27 stabilized steps for seven different fuel blends from pure fossil diesel (B0) to pure biodiesel (B100), considering also B10, B15, B20, B30, B50 fuel blends. The cycle imposed tries to simulate a normal use of a bus in an urban and extra-urban circuit, considering different engine rotation and loads applied. An analysis on consumption data obtained of a fleet was made. The fleet had near 200 buses, used different fuel blends, and operated in the north of Portugal. Results reveal that the cycle imposed reflects very well the tendency of consumption, allowing to confirm the methodology and also to check influences on consumption, mainly associated with possibilities to decrease CO2 emissions by using some biodiesel blends on buses. This allows increasing the quality of data in vehicle real use and tightening the uncertainties on the actual effects of using biodiesel.

  14. Report on FS survey for project of introduction of highly energy-efficient trolley buses into the Mexico Metropolitan Area in FY 1997; 1997 nendo chosa hokokusho (Mexico city eno sho energy gata trolley bus donyu project FS chosa)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Traffic jam and air pollution by automobiles are currently getting severe in the Mexico Metropolitan Area. Trolley buses were introduced for improving the environment more than ten years ago. Vehicles become too old for use, and their energy efficiency is low. In this project, 200 highly energy-efficient trolley buses are introduced to replace old inefficient trolley buses, which results in the improved traffic convenience in the City and enhanced energy efficiency. The new energy-efficient trolley buses are made of energy-efficient control VVVF inverters produced and exported by MELCO (Mitsubishi Electric Corporation), energy-efficient motors by MELMEX (Mitsubishi Electric Corporation, Mexico), and bodies by MASA which is a major manufacturer of bus bodies. The objective of this research is to analyze the background of introduction of new energy-efficient trolley buses and the effects of the present project. The results of analysis are going to be utilized for future promotion of the Joint Implementation and Clean Development Mechanism. 30 refs., 30 figs., 24 tabs.

  15. Particle size and velocity measurement in flames by laser anemometer

    Science.gov (United States)

    Chigier, N. A.; Ungut, A.; Yule, A. J.

    1979-01-01

    Simultaneous droplet size and velocity measurements by a particle counting Laser Doppler Anemometer (LDA) in kerosene fuel sprays under burning and non-burning conditions are presented. Particle sizes are derived from pulse height analysis of the mean LDA signals and velocities are simultaneously determined by measuring Doppler shift frequencies. The measurements show that droplet velocity is a function of droplet diameter for burning and non-burning conditions, and spatially averaged size distributions are derived from velocity data. A comparison of results obtained under burning and non-burning conditions show changes in size distribution due to preferential vaporization of small droplets, acceleration due to thermal expansion of gases, and corresponding changes in droplet momentum.

  16. Repeated Habitat Disturbances by Fire Decrease Local Effective Population Size.

    Science.gov (United States)

    Schrey, Aaron W; Ragsdale, Alexandria K; McCoy, Earl D; Mushinsky, Henry R

    2016-07-01

    Effective population size is a fundamental parameter in population genetics, and factors that alter effective population size will shape the genetic characteristics of populations. Habitat disturbance may have a large effect on genetic characteristics of populations by influencing immigration and gene flow, particularly in fragmented habitats. We used the Florida Sand Skink (Plestiodon reynoldsi) to investigate the effect of fire-based habitat disturbances on the effective population size in the highly threatened, severely fragmented, and fire dependent Florida scrub habitat. We screened 7 microsatellite loci in 604 individuals collected from 12 locations at Archbold Biological Station. Archbold Biological Station has an active fire management plan and detailed records of fires dating to 1967. Our objective was to determine how the timing, number, and intervals between fires affect effective population size, focusing on multiple fires in the same location. Effective population size was higher in areas that had not been burned for more than 10 years and decreased with number of fires and shorter time between fires. A similar pattern was observed in abundance: increasing abundance with time-since-fire and decreasing abundance with number of fires. The ratio of effective population size to census size was higher at sites with more recent fires and tended to decrease with time-since-last-fire. These results suggest that habitat disturbances, such as fire, may have a large effect in the genetic characteristics of local populations and that Florida Sand Skinks are well adapted to the natural fire dynamics required to maintain Florida scrub. PMID:26976940

  17. Termites assess wood size by using vibration signals

    OpenAIRE

    Evans, Theodore A.; Lai, Joseph C. S.; Toledano, Emilie; McDowall, Lee; Rakotonarivo, Sandrine; Lenz, Michael

    2005-01-01

    International audience Contrary to the common perception that termites are indiscrimi-nant eaters, termites choose their food carefully; however, the methods by which they choose food are not well understood. Using choice experiments and recordings of termites feeding on wooden blocks of different sizes, we show that worker drywood termites (Cryptotermes domesticus) use the resonant frequency of a block of wood to assess its size. Drywood termites showed differences in their response to vi...

  18. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2009

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.; Gikakis, C.

    2009-10-01

    This report documents progress in meeting the technological challenges of fuel cell propulsion for transportation based on current fuel cell transit bus demonstrations and plans for more fuel cell transit buses and hydrogen infrastructure.

  19. Egg size matching by an intraspecific brood parasite

    Science.gov (United States)

    Lemons, Patrick R.; Sedinger, James S.

    2011-01-01

    Avian brood parasitism provides an ideal system with which to understand animal recognition and its affect on fitness. This phenomenon of laying eggs in the nests of other individuals has classically been framed from the perspective of interspecific brood parasitism and host recognition of parasitic eggs. Few examples exist of strategies adopted by intraspecific brood parasites to maximize success of parasitic eggs. Intraspecific brood parasitism within precocial birds can be a risky strategy in that hatch synchrony is essential to reproductive success. Given that egg size is positively correlated with incubation time, parasitic birds would benefit by recognizing and selecting hosts with a similar egg size. Intraspecific brood parasitism is an alternative reproductive strategy in black brant (Branta bernicla nigricans), a colonial nesting goose with precocial young. Based on a randomization test, parasitic eggs in this study differed less in size from eggs in their host's nests than did random eggs placed in random nests. Parasitic eggs were remarkably similar in size to hosts’ eggs, differing by parasitic brant match the egg size of hosts in our study supports our hypothesis that brant match egg size of hosts, thereby maximizing hatching success of their parasitic eggs.

  20. Ecosystem size matters: the dimensionality of intralacustrine diversification in Icelandic stickleback is predicted by lake size.

    Science.gov (United States)

    Lucek, Kay; Kristjánsson, Bjarni K; Skúlason, Skúli; Seehausen, Ole

    2016-08-01

    Cases of evolutionary diversification can be characterized along a continuum from weak to strong genetic and phenotypic differentiation. Several factors may facilitate or constrain the differentiation process. Comparative analyses of replicates of the same taxon at different stages of differentiation can be useful to identify these factors. We estimated the number of distinct phenotypic groups in three-spine stickleback populations from nine lakes in Iceland and in one marine population. Using the inferred number of phenotypic groups in each lake, genetic divergence from the marine population, and physical lake and landscape variables, we tested whether ecosystem size, approximated by lake size and depth, or isolation from the ancestral marine gene pool predicts the occurrence and the extent of phenotypic and genetic diversification within lakes. We find intralacustrine phenotypic diversification to be the rule rather than the exception, occurring in all but the youngest lake population and being manifest in ecologically important phenotypic traits. Neutral genetic data further indicate nonrandom mating in four of nine studied lakes, and restricted gene flow between sympatric phenotypic groups in two. Although neither the phenotypic variation nor the number of intralacustrine phenotypic groups was associated with any of our environmental variables, the number of phenotypic traits that were differentiated was significantly positively related to lake size, and evidence for restricted gene flow between sympatric phenotypic groups was only found in the largest lakes where trait specific phenotypic differentiation was highest. PMID:27551381

  1. Sample size in qualitative interview studies: guided by information power

    DEFF Research Database (Denmark)

    Malterud, Kirsti; Siersma, Volkert Dirk; Guassora, Ann Dorrit Kristiane

    2016-01-01

    Sample sizes must be ascertained in qualitative studies like in quantitative studies but not by the same means. The prevailing concept for sample size in qualitative studies is “saturation.” Saturation is closely tied to a specific methodology, and the term is inconsistently applied. We propose the...... concept “information power” to guide adequate sample size for qualitative studies. Information power indicates that the more information the sample holds, relevant for the actual study, the lower amount of participants is needed. We suggest that the size of a sample with sufficient information power...... depends on (a) the aim of the study, (b) sample specificity, (c) use of established theory, (d) quality of dialogue, and (e) analysis strategy. We present a model where these elements of information and their relevant dimensions are related to information power. Application of this model in the planning...

  2. In-use fuel economy of hybrid-electric school buses in Iowa.

    Science.gov (United States)

    Hallmark, Shauna; Sperry, Bob; Mudgal, Abhisek

    2011-05-01

    Although it is much safer and more fuel-efficient to transport children to school in buses than in private vehicles, school buses in the United States still consume 822 million gal of diesel fuel annually, and school transportation costs can account for a significant portion of resource-constrained school district budgets. Additionally, children in diesel-powered school buses may be exposed to higher levels of particulates and other pollutants than children in cars. One solution to emission and fuel concerns is use of hybrid-electric school buses, which have the potential to reduce emissions and overall lifecycle costs compared with conventional diesel buses. Hybrid-electric technologies are available in the passenger vehicle market as well as the transit bus market and have a track record indicating fuel economy and emissions benefits. This paper summarizes the results of an in-use fuel economy evaluation for two plug-in hybrid school buses deployed in two different school districts in Iowa. Each school district selected a control bus with a route similar to that of the hybrid bus. Odometer readings, fuel consumption, and maintenance needs were recorded for each bus. The buses were deployed in 2008 and data were collected through May 2010. Fuel consumption was calculated for each school district. In Nevada, IA, the overall average fuel economy was 8.23 mpg for the hybrid and 6.35 mpg for the control bus. In Sigourney, IA, the overall average fuel economy was 8.94 mpg for the hybrid and 6.42 mpg for the control bus. The fuel consumption data were compared for the hybrid and control buses using a Wilcoxon signed rank test. Results indicate that fuel economy for the Nevada hybrid bus was 29.6% better than for the Nevada control bus, and fuel economy for the Sigourney hybrid bus was 39.2% higher than for the Sigourney control bus. Both differences were statistically significant. PMID:21608490

  3. Cool Science: K-12 Climate Change Art Displayed on Buses

    Science.gov (United States)

    Chen, R. F.; Lustick, D. S.; Lohmeier, J.; Thompson, S. R.

    2015-12-01

    Cool science is an art contest where K12 students create placards (7" x 22") to educate the public about climate change. Students are prompted to create their artwork in response to questions such as: What is the evidence for climate change? How does climate change impact your local community? What can you do to reduce the impacts of climate change? In each of three years, 500-600 student entrees have been submitted from more than 12 school districts across Massachusetts. A panel of judges including scientists, artists, rapid transit representatives, and educators chooses elementary, middle, and high school winners. Winners (6), runners-up (6), and honorable mentions (12) and their families and teachers are invited to an annual Cool Science Award Ceremony to be recognized and view winning artwork. All winning artwork is posted on the Cool Science website. The winning artwork (2 per grade band) is converted into placards (11" x 28") and posters (2.5' x 12') that are placed on the inside (placards) and outside (posters) of buses. Posters are displayed for one month. So far, Cool Science was implemented in Lowell, MA where over 5000 public viewers see the posters daily on the sides of Lowell Rapid Transit Authority (LRTA) buses, making approximately 1,000,000 impressions per year. Cool Science acts to increase climate literacy in children as well as the public, and as such promotes intergenerational learning. Using art in conjunction with science learning about climate change appears to be effective at engaging not just traditionally high achieving science students, but also those interested in the creative arts. Hearing winners' stories about how they created their artwork and what this contest meant to them supports the idea that Cool Science attracts a wide diversity of students. Parents discuss climate change with their children. Multiple press releases announcing the winners further promotes the awareness of climate change throughout school districts and their

  4. Kinetics of crystallite size evolution by ball milling

    Directory of Open Access Journals (Sweden)

    Zdujić Miodrag V.

    2002-01-01

    Full Text Available One of the distinguishing features of mechanochemical treatment is crystallite size reduction. The crystallite size of the powder subjected to milling decreases to some minimal value characteristic for the given material. Two processes occur concurrently during milling: reduction of the crystallite size and grain growth, whereby the steady-state crystallite size is attained when the rates of these processes are in equilibrium. This study deals with the kinetics of crystallite size evolution by milling. Published experimental data were analyzed using three kinetic models: dr / dt=-k1r2 + k2r-1; dr / dt=-k1r3 + k2r and dr / dt=-nktn-1(r - rs, where r and rs are the crystallite radius and steady-state crystallite radius respectively, t time, k1 and k2 the rate constants of crystallite reduction and grain growth, respectively, k the rate constant and n the Avrami exponent. The applied kinetic relations describe the crystallite size dependence on milling time in a satisfactory manner.

  5. Evaluation of retrofit crankcase ventilation controls and diesel oxidation catalysts for reducing air pollution in school buses

    Science.gov (United States)

    Trenbath, Kim; Hannigan, Michael P.; Milford, Jana B.

    2009-12-01

    This study evaluates the effect of retrofit closed crankcase ventilation filters (CCFs) and diesel oxidation catalysts (DOCs) on the in-cabin air quality in transit-style diesel school buses. In-cabin pollution levels were measured on three buses from the Pueblo, CO District 70 fleet. Monitoring was conducted while buses were driven along their regular routes, with each bus tested three times before and three times after installation of control devices. Ultrafine number concentrations in the school bus cabins were 33-41% lower, on average, after the control devices were installed. Mean mass concentrations of particulate matter less than 2.5 μm in diameter (PM2.5) were 56% lower, organic carbon (OC) 41% lower, elemental carbon (EC) 85% lower, and formaldehyde 32% lower after control devices were installed. While carbon monoxide concentrations were low in all tests, mean concentrations were higher after control devices were installed than in pre-retrofit tests. Reductions in number, OC, and formaldehyde concentrations were statistically significant, but reductions in PM2.5 mass were not. Even with control devices installed, during some runs PM2.5 and OC concentrations in the bus cabins were elevated compared to ambient concentrations observed in the area. OC concentrations inside the bus cabins ranged from 22 to 58 μg m -3 before and 13 to 33 μg m -3 after control devices were installed. OC concentrations were correlated with particle-bound organic tracers for lubricating oil emissions (hopanes) and diesel fuel and tailpipe emissions (polycyclic aromatic hydrocarbons (PAH) and aliphatic hydrocarbons). Mean concentrations of hopanes, PAH, and aliphatic hydrocarbons were lower by 37, 50, and 43%, respectively, after the control devices were installed, suggesting that both CCFs and DOCs were effective at reducing in-cabin OC concentrations.

  6. Synthesis of size-controlled Bi particles by electrochemical deposition

    Indian Academy of Sciences (India)

    C N Tharamani; H C Thejaswini; S Sampath

    2008-06-01

    Small sized bismuth particles are prepared by an electrochemical method using a triple voltage pulse technique. The bath composition and electrochemical parameters are optimized to yield monodisperse particles. The particles have been characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, UV-visible spectroscopy and X-ray diffraction technique. The particles, as deposited, are highly crystalline in nature and the particle size and shape get tuned depending on the conditions of deposition.

  7. Distortions of glacial landform sizes by manual mapping

    Science.gov (United States)

    Hillier, John K.; Smith, Mike J.

    2016-04-01

    Mapped topographic features are important for understanding processes that sculpt the Earth's surface. Subjective manual techniques are commonly used for mapping, yet how effective they are in quantitative terms is poorly constrained. Here 12,121 outlines drawn by 25 interpreters searching for a total of 21,625 drumlins in 5 synthetic DEMs are interpreted in terms of how the manual mapping process distorts the height (H), width (W) and length (L) of the reported features. Bias in the size-frequency distributions is caused by the sub-set of the forms 'found', even assuming perfect extraction of sizes, and is governed by H driving detectability. Bias is then compounded in sizes that are extracted using the mapped outlines but, remarkably, the size-frequency distribution is not altered further when mappers' incorrect guesses (i.e. outline corresponds to no input synthetic drumlin) are then included; it seems possible that, once mappers have their 'eye in' based on the most clearly defined features, they are very effective at identifying similar morphologies. Of the metrics available to quantify the size of a population, maximum size and λ, the exponent of its tail, are the most robust to these distortions. The drumlins in the study area resemble UK drumlins, permitting extrapolation of the conclusions. These are the first results to give such granular insights into the impacts of the various stages in manually mapping glacial landforms, permitted by the development of the synthetic DEMs. Arguments will always exist about how realistic any synthetic is, but this work demonstrates another use of synthetic DEMs that may be applied more widely in geomorphology.

  8. Credit rationing by loan size: a synthesized model

    OpenAIRE

    Kjenstad, Einar; Su, Xunhua

    2012-01-01

    We construct a unified framework to study credit rationing by the loan size. Due to default risk, the loan offer curve is positive-sloping. At the equilibrium interest rate, increasing the loan size reduces the average cost of the loan, so the borrower always demands a larger loan than that the lender can offer even in a perfect credit market. We show that any agency cost may shift the loan offer curve upwards, enlarging the excess demand further. If agency costs are sufficiently high, the bo...

  9. FRACTIONATION OF PULP AND PAPER PARTICLES SELECTIVELY BY SIZE

    Directory of Open Access Journals (Sweden)

    Ossi Tapio Laitinen

    2011-02-01

    Full Text Available A study was made of the classification of pulp, paper, and peat particles by size with a device called a tube flow fractionator. An accurate and simple experimental model was formulated in order to estimate the time required for fractionation, yielding an excellent correlation between the observed and predicted fractionation times. The results showed that the fractionation time of a certain size of pulp, paper, and peat particles in the tube flow device can be accurately estimated from the length, width, and thickness of the particle. The results can be used to facilitate the selection of specific fractions of pulp and paper samples.

  10. On the maximum grain size entrained by photoevaporative winds

    CERN Document Server

    Hutchison, Mark A; Maddison, Sarah T

    2016-01-01

    We model the behaviour of dust grains entrained by photoevaporation-driven winds from protoplanetary discs assuming a non-rotating, plane-parallel disc. We obtain an analytic expression for the maximum entrainable grain size in extreme-UV radiation-driven winds, which we demonstrate to be proportional to the mass loss rate of the disc. When compared with our hydrodynamic simulations, the model reproduces almost all of the wind properties for the gas and dust. In typical turbulent discs, the entrained grain sizes in the wind are smaller than the theoretical maximum everywhere but the inner disc due to dust settling.

  11. Size of the top jet drop produced by bubble bursting

    CERN Document Server

    Ghabache, Elisabeth

    2016-01-01

    As a bubble bursts at a liquid-air interface, a tiny liquid jet rises and can release the so-called \\textit{jet drops}. In this paper, the size of the top jet drop produced by a bubble bursting is investigated experimentally. We determine, and discuss, the first scaling law enabling the determination of the top jet drop size as a function of the corresponding mother bubble radius and the liquid properties (viscosity, surface tension, density), along with its regime of existence. Furthermore, in the aim of decoupling experimentally the effects of bubble collapse and jet dynamics on the drop detachment, we propose a new scaling providing the top drop size only as a function of the jet velocity and liquid parameters. In particular, this allows us to untangle the intricate roles of viscosity, gravity and surface tension in the \\textit{end-pinching} of the bubble bursting jet.

  12. Mosquito consumption by insectivorous bats: does size matter?

    Science.gov (United States)

    Gonsalves, Leroy; Bicknell, Brian; Law, Brad; Webb, Cameron; Monamy, Vaughan

    2013-01-01

    Insectivorous bats have often been touted as biological control for mosquito populations. However, mosquitoes generally represent only a small proportion of bat diet. Given the small size of mosquitoes, restrictions imposed on prey detectability by low frequency echolocation, and variable field metabolic rates (FMR), mosquitoes may not be available to or profitable for all bats. This study investigated whether consumption of mosquitoes was influenced by bat size, which is negatively correlated with echolocation frequency but positively correlated with bat FMR. To assess this, we investigated diets of five eastern Australian bat species (Vespadelus vulturnus Thomas, V. pumilus Gray, Miniopterus australis Tomes, Nyctophilus gouldi Tomes and Chalinolobus gouldii Gray) ranging in size from 4-14 g in coastal forest, using molecular analysis of fecal DNA. Abundances of potential mosquito and non-mosquito prey were concurrently measured to provide data on relative prey abundance. Aedes vigilax was locally the most abundant mosquito species, while Lepidoptera the most abundant insect order. A diverse range of prey was detected in bat feces, although members of Lepidoptera dominated, reflecting relative abundance at trap sites. Consumption of mosquitoes was restricted to V. vulturnus and V. pumilus, two smaller sized bats (4 and 4.5 g). Although mosquitoes were not commonly detected in feces of V. pumilus, they were present in feces of 55 % of V. vulturnus individuals. To meet nightly FMR requirements, Vespadelus spp. would need to consume ~600-660 mosquitoes on a mosquito-only diet, or ~160-180 similar sized moths on a moth-only diet. Lower relative profitability of mosquitoes may provide an explanation for the low level of mosquito consumption among these bats and the absence of mosquitoes in feces of larger bats. Smaller sized bats, especially V. vulturnus, are likely to be those most sensitive to reductions in mosquito abundance and should be monitored during mosquito

  13. Size separation of DNA molecules by pulsed electric field dielectrophoresis

    International Nuclear Information System (INIS)

    In this paper we propose an electrode design and a switching pattern of the applied DC electrode potentials for a microfluidic device to be used in size separation of DNA molecules. Estimates on the separation resolution, which are based on numerical solutions of a Newton-type equation on time-averaged quantities, are presented for an input batch sample of DNA fragments with sizes up to 220 base pairs (bp). The active area of the device (which can be microfabricated by standard photolitographic techniques) is a channel 6 μm wide, 8 μm deep and 150 μm in length, flanked by 23 plane parallel integrated electrodes, individually addressed with low DC voltages, up to ± 25 V. In the active area a time-dependent non-uniform electric field, or a travelling dielectrophoretic wave (TDW) is being produced. In order to enhance the separation resolution, the polarization DC potentials are switched with a relatively high frequency (∼ 10-7 s), which is chosen accordingly with the buffer conductivity and dielectric constants of the fluid and particles. Since the external field is of DC type, we put forward an explanatory model of the dielectric response of the DNA to the time-dependent applied field. We then numerically investigate the size-dependent response of the DNA in a low conductivity buffer (∼0.01 Ω-1 m-1) under the influence of the electric field, which is calculated by means of the method of moments. The results of the computer modelling indicate the existence of a threshold value for the size of the successfully transported molecules, which can be adjusted by varying the velocity of the dielectrophoretic wave produced by the system. The estimated error in selecting a chosen group of molecules with sizes above a specified value is about 5 bp, while the processing times are of the order of hundred of seconds

  14. Cost Effectiveness Analysis of Quasi-Static Wireless Power Transfer for Plug-In Hybrid Electric Transit Buses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lijuan; Gonder, Jeff; Burton, Evan; Brooker, Aaron; Meintz, Andrew; Konan, Arnaud

    2015-10-19

    This study evaluates the costs and benefits associated with the use of a stationary-wireless- power-transfer-enabled plug-in hybrid electric bus and determines the cost effectiveness relative to a conventional bus and a hybrid electric bus. A sensitivity sweep was performed over many different battery sizes, charging power levels, and number/location of bus stop charging stations. The net present cost was calculated for each vehicle design and provided the basis for design evaluation. In all cases, given the assumed economic conditions, the conventional bus achieved the lowest net present cost while the optimal plug-in hybrid electric bus scenario beat out the hybrid electric comparison scenario. The study also performed parameter sensitivity analysis under favorable and high unfavorable market penetration assumptions. The analysis identifies fuel saving opportunities with plug-in hybrid electric bus scenarios at cumulative net present costs not too dissimilar from those for conventional buses.

  15. IFA and PIFA Size Reduction by Using a Stub Loading

    Directory of Open Access Journals (Sweden)

    Jose Alfredo Tirado-Mendez

    2013-01-01

    Full Text Available A proposed technique for size reduction of a conventional inverted-F antenna (IFA and a planar inverted-F antenna (PIFA by employing a reactive load generated by a short-circuited stub is presented. The reduction factor of both antennas is around 30%, and the main parameters of the devices are preserved, including a fractional bandwidth of 4% and a gain of −2 dB. Both antennas operate around 1.5 GHz.

  16. IFA and PIFA Size Reduction by Using a Stub Loading

    OpenAIRE

    Jose Alfredo Tirado-Mendez; Rene Acevo-Herrera; Ruben Flores-Leal; Roberto Linares-Miranda; Hildeberto Jardon-Aguilar

    2013-01-01

    A proposed technique for size reduction of a conventional inverted-F antenna (IFA) and a planar inverted-F antenna (PIFA) by employing a reactive load generated by a short-circuited stub is presented. The reduction factor of both antennas is around 30%, and the main parameters of the devices are preserved, including a fractional bandwidth of 4% and a gain of −2 dB. Both antennas operate around 1.5 GHz.

  17. Evaluation of Alternative Field Buses for Lighting ControlApplications

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Ed; Rubinstein, Francis

    2005-03-21

    The Subcontract Statement of Work consists of two major tasks. This report is the Final Report in fulfillment of the contract deliverable for Task 1. The purpose of Task 1 was to evaluate existing and emerging protocols and standards for interfacing sensors and controllers for communicating with integrated lighting control systems in commercial buildings. The detailed task description follows: Task 1. Evaluate alternative sensor/field buses. The objective of this task is to evaluate existing and emerging standards for interfacing sensors and controllers for communicating with integrated lighting control systems in commercial buildings. The protocols to be evaluated will include at least: (1) 1-Wire Net, (2) DALI, (3) MODBUS (or appropriate substitute such as EIB) and (4) ZigBee. The evaluation will include a comparative matrix for comparing the technical performance features of the different alternative systems. The performance features to be considered include: (1) directionality and network speed, (2) error control, (3) latency times, (4) allowable cable voltage drop, (5) topology, and (6) polarization. Specifically, Subcontractor will: (1) Analyze the proposed network architecture and identify potential problems that may require further research and specification. (2) Help identify and specify additional software and hardware components that may be required for the communications network to operate properly. (3) Identify areas of the architecture that can benefit from existing standards and technology and enumerate those standards and technologies. (4) Identify existing companies that may have relevant technology that can be applied to this research. (5) Help determine if new standards or technologies need to be developed.

  18. Human vocal attractiveness as signaled by body size projection.

    Directory of Open Access Journals (Sweden)

    Yi Xu

    Full Text Available Voice, as a secondary sexual characteristic, is known to affect the perceived attractiveness of human individuals. But the underlying mechanism of vocal attractiveness has remained unclear. Here, we presented human listeners with acoustically altered natural sentences and fully synthetic sentences with systematically manipulated pitch, formants and voice quality based on a principle of body size projection reported for animal calls and emotional human vocal expressions. The results show that male listeners preferred a female voice that signals a small body size, with relatively high pitch, wide formant dispersion and breathy voice, while female listeners preferred a male voice that signals a large body size with low pitch and narrow formant dispersion. Interestingly, however, male vocal attractiveness was also enhanced by breathiness, which presumably softened the aggressiveness associated with a large body size. These results, together with the additional finding that the same vocal dimensions also affect emotion judgment, indicate that humans still employ a vocal interaction strategy used in animal calls despite the development of complex language.

  19. Particle size and packing characterization by diffuse light transmission

    Institute of Scientific and Technical Information of China (English)

    Henrik Ehlers; Jyrki Hein(a)m(a)ki; Jouko Yliruusi

    2012-01-01

    Particle size,packing density and blend composition of glass ballotini,microcrystalline cellulose pellets and theophylline granules were studied by diffuse light transmission.Diffuse visible light was directed to the sample and the intensity of the light transmitted to the opposite side of the sample was measured through a diffusing lens using a phototransistor.Light transmission was found to decrease with decreasing particle size and with increasing packing density.There was a correlation,though somewhat irregular,between light transmission and particle size for glass ballotini and microcrystalline cellulose pellets,and a strong near-linear correlation between light transmission and particle size for theophylline granules.The effect of packing density on light transmission was significant.Differentiating the composition of binary blends of microcrystalline cellulose pellets and glass ballotini and blends of theophylline granules was found possible on the basis of light transmission.The method proposed showed potential as a rapid,simple and inexpensive analytical tool for basic process diagnostics.

  20. Modeling size effects on fracture toughness by dislocation dynamics

    International Nuclear Information System (INIS)

    The effects of grain size and of crack-tip blunting radius on the fracture toughness of tungsten polycrystals are studied by using a combined dislocation dynamics/cohesive zone model (CZM). Two-dimensional dislocation dynamics are employed to analyze crack-tip plasticity and crack propagation is characterized by a CZM. The geometry of the crack and the corresponding boundary conditions are described by means of a boundary element method with dislocation dipoles as fundamental solution. Grain boundaries are introduced as obstacles for dislocation motion. Numerical experiments reveal that the fracture toughness decreases with grain size, because grain boundaries confine the plastic zone. This effect is particularly pronounced at small loading rates, where the unconfined plastic zone is large. Our results also show that fracture toughness scales with the tip radius as the stress concentration at the crack tip is reduced and the plastic zone is enlarged.

  1. Modeling size effects on fracture toughness by dislocation dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, X.H. [Interdisciplinary Centre for Advanced Materials Simulation, Ruhr-University Bochum, Stiepeler Str. 129 (UHW), 44801 Bochum (Germany); Hartmaier, A., E-mail: Alexander.Hartmaier@ruhr-uni-bochum.de [Interdisciplinary Centre for Advanced Materials Simulation, Ruhr-University Bochum, Stiepeler Str. 129 (UHW), 44801 Bochum (Germany)

    2010-01-15

    The effects of grain size and of crack-tip blunting radius on the fracture toughness of tungsten polycrystals are studied by using a combined dislocation dynamics/cohesive zone model (CZM). Two-dimensional dislocation dynamics are employed to analyze crack-tip plasticity and crack propagation is characterized by a CZM. The geometry of the crack and the corresponding boundary conditions are described by means of a boundary element method with dislocation dipoles as fundamental solution. Grain boundaries are introduced as obstacles for dislocation motion. Numerical experiments reveal that the fracture toughness decreases with grain size, because grain boundaries confine the plastic zone. This effect is particularly pronounced at small loading rates, where the unconfined plastic zone is large. Our results also show that fracture toughness scales with the tip radius as the stress concentration at the crack tip is reduced and the plastic zone is enlarged.

  2. Measurement of DNA size by fluorescence-fluctuation spectroscopy

    International Nuclear Information System (INIS)

    This report covers research on measuring the size of very large DNA molecules by fluorescence-fluctuation spectroscopy. The primary reason was to measure the formation of DNA double-strand breaks in mammalian cells by agents such as ionizing radiation, and to measure the repair of these breaks. Fluorescence-fluctuation spectroscopy was employed because it is known to be able to measure the size of DNA of molecular weight greater than 109 (Weissman, et al., 1976). Most of this report is devoted to the techniques of fluorescent fluctuation spectroscopy. Using the procedures described here, it is likely that measurements could be made of DNA of molecular weight 1010, which would be formed in mammalian cells given 1000 rads of x-rays

  3. The Size of Software Projects Developed by Mexican Companies

    OpenAIRE

    Aguilar, Jorge; Sanchez, Moises; Fernandez-y-Fernandez, Carlos; Rocha, Everth; Martinez, David; Figueroa, Jose

    2014-01-01

    Currently, most software projects around the world are small rather than large. Despite this, there are more methodologies, tools, frameworks, processes, and so on, for developing and managing large software projects than for small ones. Small software projects are important because they generate considerable resources. For example: apps (small mobile applications) generate around $25 billion dollars of revenue. This paper shows our findings regarding the size of the projects built by Mexican...

  4. Load demand profile for a large charging station of a fleet of all-electric plug-in buses

    Directory of Open Access Journals (Sweden)

    Mario A. Rios

    2014-08-01

    Full Text Available This study proposes a general procedure to compute the load demand profile from a parking lot where a fleet of buses with electric propulsion mechanisms are charged. Such procedure is divided in three different stages, the first one models the daily energy utilisation of the batteries based on Monte Carlo simulations and route characteristics. The second one models the process in the charging station based on discrete event simulation of queues of buses served by a lot of available chargers. The third step computes the final demand profile in the parking lot because of the charging process based on the power consumption of batteries’ chargers and the utilisation of the available charges. The proposed procedure allows the computation of the number of required batteries’ chargers to be installed in a charging station placed at a parking lot in order to satisfy and ensure the operation of the fleet, the computation of the power demand profile and the peak load and the computation of the general characteristics of electrical infrastructure to supply the power to the station.

  5. The effects of urban driving conditions on the operating characteristics of conventional and hybrid electric city buses

    International Nuclear Information System (INIS)

    Highlights: • Operating characteristics of conventional and hybrid electric buses were examined. • Recovery of braking energy offers an excellent opportunity to improve fuel economy. • Speed and altitude profiles of routes have dramatic impacts on the energy recovery. • Capacity of the auxiliary power source has a dramatic impact on the energy recovery. • Round-trip efficiency of the regenerative braking system was calculated to be 27%. - Abstract: The basic operating characteristics of a conventional bus (CB) and a hybrid electric bus (HEB) were examined under urban driving conditions. To perform this examination, real-time operating data from the buses were collected on the Campus-Return route of the Sakarya Municipality. The main characteristics examined were the traction, braking, engine, engine generator unit (EGU), motor/generator (M/G), and ultracapacitor (Ucap) energies and efficiencies of the buses. The route elevation profile and the frequency of stop-and-go operations of the buses were found to have dramatic impacts on the braking and traction energies of the buses. The declining profile of the Campus-Return route provided an excellent opportunity for energy recovery by the regenerative braking system of the HEB. However, owing to the limits on the capacities and efficiencies of the hybrid drive train components and the Ucap, the bus braking energies were not recovered completely. Braking energies as high as 2.2 kW h per micro-trip were observed, but less than 1 kW h of braking energy per micro-trip was converted to electricity by the M/G; the rest of the braking energy was wasted in frictional braking. The maximum energy recovered and stored in the Ucap per micro-trip was 0.5 kW h, but the amount of energy recovered and stored per micro-trip was typically less than 0.2 kW h for the entire route. The cumulative braking energy recovered and stored in the Ucap for the Campus-Return route was 52% of the available brake energy, which was 13.02 kW h

  6. Fuel Cell Buses in U.S. Transit Fleets: Current Status 2010

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.; Gigakis, C.

    2010-11-01

    This status report, fourth in a series of annual status reports from the U.S. Department of Energy's National Renewable Energy Laboratory, summarizes progress and accomplishments from demonstrations of fuel cell transit buses in the United States. This year's assessment report provides the results from the fifth year of operation of five Van Hool, ISE, and UTC Power fuel cell buses operating at AC Transit, SunLine, and CTTRANSIT. The achievements and challenges of this bus design, implementation, and operating are presented, with a focus on the next steps for implementing larger numbers and new and different designs of fuel cell buses. The major positive result from nearly five years of operation is the dramatic increase in reliability experienced for the fuel cell power system.

  7. Fish egg size: a characteristic determined by parental care

    Directory of Open Access Journals (Sweden)

    Rosana RM Mazzoni

    2015-12-01

    Full Text Available The existence of a trade-off between relative batch fecundity and egg size has been widely documented (e.g. Brown & Shine 2009. Studies on the evolution of parental care and its relationship with fish egg size were stimulated by the work of Shine (1978, who proposed several possible hypotheses, including one that predicted that the onset of parental care preceded the increase in egg size. This hypothesis has since been challenged by Nussbaum & Schultz (1989 and more recently by Summers et al. (2006, who proposed an alternative hypothesis in which the evolution of large eggs was said to precede the evolution of parental care and not the reverse. Here, we examined 313 species of bony fish, including 152 species with parental care (PC and 161 species without parental care (NPC, and found evidence that fully supports the hypothesis of Shine (1978. Additionally, we explain how strengthening this hypothesis could impact the development of phylogenies. We also make suggestions for future studies on gene regulatory mechanisms that could explain the evolution of parental care and egg size in bony fish within a more modern context of developmental ecology. Our analysis uses data describing the mean size of ripe eggs and the occurrence of parental care in 313 species of bony fish belonging to 53 families in 11 orders. Data for 22 of the 313 species were collected by us from the Tocantins River. Data for the remaining species were obtained from the literature: 6 species from the Paraná River (Suzuki et al. 2000, 149 species from large African lakes and some pelagic marine species (Duponchelle et al. 2008, 74 marine species (Pauly & Pullin 1988, and 65 species from the Tocantins River (Neuberger 2010. Of these 313 total species, 161 (51.4% are PC species and 152 (48.6% are NPC species. We analyzed a minimum of eight mature females from each of the 16 species we collected, and for each female, we measured 10 mature oocytes and derived the mean diameter of

  8. One portion size of foods frequently consumed by Korean adults

    OpenAIRE

    Choi, Mi-Kyeong; Hyun, Wha-Jin; Lee, Sim-Yeol; Park, Hong-Ju; Kim, Se-Na; Song, Kyung-Hee

    2010-01-01

    This study aimed to define a one portion size of food items frequently consumed for convenient use by Koreans in food selection, diet planning, and nutritional evaluation. We analyzed using the original data on 5,436 persons (60.87%) aged 20 ~ 64 years among 8,930 persons to whom NHANES 2005 and selected food items consumed by the intake frequency of 30 or higher among the 500 most frequently consumed food items. A total of 374 varieties of food items of regular use were selected. And the por...

  9. Exposures due to emissions from ethanol and diesel fuelled buses in Stockholm

    Energy Technology Data Exchange (ETDEWEB)

    Otson, R. [Health Canada, Ottawa, ON (Canada); Westerholm, R. [Stockholm Univ. (Sweden). Dept. of Analytical Chemistry; Fellin, P.; Davis, C. [BOVAR Environmental, Toronto, ON (Canada)

    1997-12-01

    Personal exposure and ambient concentrations of 105 chemical species were determined during September in Stockholm, a northern urban area. This unique study provided personal exposure data equivalent to 8 person-days each on diesel and ethanol buses, and 12 person-days on streets in the urban area. If used judiciously, these data, and the ambient data, are useful for risk assessment, as well as for validation of dispersion models. The concentrations for many species were relatively low, when compared to results from other studies of outdoor concentrations in urban areas. This was probably due to the meteorological conditions during the study which favoured low concentrations. Personal exposures were generally higher than ambient concentrations, probably because of the proximity of subjects to sources of contaminants. As expected, alcohol compounds were found at greater levels in ethanol fueled buses and at bus stops on routes with predominantly ethanol fueled buses. No trends were evident for exposures of VOCs or PAC on diesel and ethanol buses. Exposures to particles at the bus stops were lower than exposures on buses, possibly due to the low traffic volumes at the bus stops, and the proximity of subjects on buses to other traffic. Upon factor analysis of the data, five factors explained the majority of the variance in the results, and showed associations between selected species and a few other parameters. These associations should be useful to design more efficient studies in the future. The chemical element mass balance results with measured profiles yielded uncertain results, but with literature profiles, the diesel and ethanol bus emissions accounted for a small fraction, i.e. < 5%, of the exposures 26 refs, 6 figs, 3 tabs

  10. Optimal Memoryless Encoding for Low Power Off-Chip Data Buses

    CERN Document Server

    Chee, Yeow Meng; Ling, Alan C H

    2007-01-01

    Off-chip buses account for a significant portion of the total system power consumed in embedded systems. Bus encoding schemes have been proposed to minimize power dissipation, but none has been demonstrated to be optimal with respect to any measure. In this paper, we give the first provably optimal and explicit (polynomial-time constructible) families of memoryless codes for minimizing bit transitions in off-chip buses. Our results imply that having access to a clock does not make a memoryless encoding scheme that minimizes bit transitions more powerful.

  11. Estimation of grain size and size inhomogeneity in ultrafine-grained aluminium processed by ECAP method

    Czech Academy of Sciences Publication Activity Database

    Ilucová, Lucia; Král, P.; Svoboda, M.; Saxl, Ivan; Sklenička, V.

    Roskilde : Riso National Laboratory, 2004, s. 363-368. [Riso International Symposium on Materials Science/25./. Roskilde (DK), 06.09.2004-10.09.2004] R&D Projects: GA ČR GA201/01/1195 Institutional research plan: CEZ:AV0Z1019905 Keywords : grain size * anisotropy * ECAP Subject RIV: BB - Applied Statistics, Operational Research

  12. Weighting by Inverse Variance or by Sample Size in Random-Effects Meta-Analysis

    Science.gov (United States)

    Marin-Martinez, Fulgencio; Sanchez-Meca, Julio

    2010-01-01

    Most of the statistical procedures in meta-analysis are based on the estimation of average effect sizes from a set of primary studies. The optimal weight for averaging a set of independent effect sizes is the inverse variance of each effect size, but in practice these weights have to be estimated, being affected by sampling error. When assuming a…

  13. Influence of malfunctions of the maintenance activities on the urban buses fuel consumption

    Science.gov (United States)

    George, Crişan; Nicolae, Filip

    2014-06-01

    Optimization of activities with the aim to provide quality service in conditions of high profitability, is one of the main objectives chased by managers in transportation companies. As a consequence, directing the attention towards monitoring of maintenance activities of vehicles fleet, can achieve desired results. Two of the most important issues related to the maintenance activity, is the increase of reliability and reduction of fuel consumption of the vehicles fleet. Aforementioned actions represents a way forward for raising the quality and profitability of services offered. In this paper, the main ways of monitoring the fuel consumption, in order to reduce it and increase the reliability of transportation vehicles fleet, are presented. For the evaluation of the maintenance system and the degree of influence of malfunctions recorded on the fuel consumption, using the Pareto -ABC method, following case study on a fleet of buses for urban public transport has been conducted. Results obtained highlights the deficiencies of the maintenance process carried out and constitutes a solid base for the reorganization of the maintenance activity, involving preventive maintenance activities, in order to contribute decisively to the results targeted by the management of transport companies.

  14. Fabrication of a uniformly sized fenofibrate microemulsion by membrane emulsification.

    Science.gov (United States)

    Pradhan, Roshan; Lee, Dong Won; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2013-01-01

    Fenofibrate-loaded microemulsions composed of Labrafil M 1944 CS, Capryol PGMC and fenofibrate as the dispersed phase and Labrasol in demineralised water as the continuous phase were prepared by utilising a Shirasu-porous-glass (SPG) membrane emulsification technique. The process parameters were optimised by adjusting the feed pressure (15-45 kPa), agitator speed (250-800 rpm) and temperature of the continuous phase (25-45°C). As a result, narrowly distributed microemulsions were obtained via SPG membrane emulsification at an agitator speed of 250 rpm, a feed pressure of 30 kPa and a continuous phase temperature of 25°C. Furthermore, TEM images clearly showed that the microemulsion prepared by SPG membrane emulsification had a uniform, spherical morphology with a narrow size distribution. Our results indicated that the SPG membrane emulsification technique is highly efficient for the preparation of narrowly distributed microemulsions with relatively smaller particle sizes compared with the common stirring method. PMID:22657749

  15. Atomic size effects studied by transport in single silicide nanowires

    Science.gov (United States)

    Miccoli, I.; Edler, F.; Pfnür, H.; Appelfeller, S.; Dähne, M.; Holtgrewe, K.; Sanna, S.; Schmidt, W. G.; Tegenkamp, C.

    2016-03-01

    Ultrathin metallic silicide nanowires with extremely high aspect ratios can be easily grown, e.g., by deposition of rare earth elements on semiconducting surfaces. These wires play a pivotal role in fundamental research and open intriguing perspectives for CMOS applications. However, the electronic properties of these one-dimensional systems are extremely sensitive to atomic-sized defects, which easily alter the transport characteristics. In this study, we characterized comprehensively TbSi2 wires grown on Si(100) and correlated details of the atomic structure with their electrical resistivities. Scanning tunneling microscopy (STM) as well as all transport experiments were performed in situ using a four-tip STM system. The measurements are complemented by local spectroscopy and density functional theory revealing that the silicide wires are electronically decoupled from the Si template. On the basis of a quasiclassical transport model, the size effect found for the resistivity is quantitatively explained in terms of bulk and surface transport channels considering details of atomic-scale roughness. Regarding future applications the full wealth of these robust nanostructures will emerge only if wires with truly atomically sharp interfaces can be reliably grown.

  16. Crystallite size determination by x-ray diffraction

    International Nuclear Information System (INIS)

    Full text: Particle sizing problem arises in many fields of science, technology and material production. Methods based on X-ray diffraction lines broadening cover size interval of 10-100 nm and are well documented. Larger crystallites demonstrate no line broadening and require alternative methods for size determination. When crystallites are relatively large (10-500 mkm) and a small volume of the sample is irradiated the diffraction pattern exhibits discrete spots instead of continuous diffraction lines. We base our approach on the linear correlation between average crystallite's size and diffraction spots dimensions which is valid for crystallite size above 5 mkm. Thus the aim of this work is to extract the crystallite size distribution function from the analysis of the spot size distribution

  17. Measurement of nugget size of spot weld by digital shearography

    Science.gov (United States)

    Yang, Lianxiang; Samala, Praveen R.; Liu, Sheng; Long, Kah Wah; Lee, Yung-Li

    2005-08-01

    Resistance spot welding is now widely used in the fabrication of sheet metals, mainly due to the cost and time considerations. Friction stir spot welding is getting more and more acceptance in the automotive industries. Such spot welds are found in nearly all products where sheet metal is joined. Obviously the quality of the spot weld has a direct impact on the quality of the product. The most important quality target of spot welds is the size of the weld nuggets. If the weld nuggets are improperly or incompletely formed, or the area surrounding the nugget is smaller than required, the structural integrity of the entire part may be uncertain. Furthermore these inconsistencies are usually internal and are seldom visible to optical inspection. This study is focused on the quality analysis of the spot welds by using "Digital Shearography". The paper mainly focuses on developing a novel, whole field technique for non-destructive inspecting the size of spot-welds, both for the resistance spot weld and the friction stir spot weld.

  18. Stereotactic radiation therapy by medium fraction size for lung tumor

    International Nuclear Information System (INIS)

    Stereotactic radiation therapy by medium fraction size (SRTm) was applied for lung tumor, we investigated to effectiveness and CT image change by treatment. Thirteen patients with lung tumor were treated with SRTm between September, 2003 and June, 2004. Nine cases were consisted as primary lung cancer, and 4 as metastatic lung cancers. Total 13 lesions were treated in 13 cases. Tumor diameter ranged from 1 cm to 4 cm, and the median was 2 cm. Body Fix was applied for patient's immobilization. The treatment planning was performed with CT simulator, X-ray simulator, and ECLIPSE. Fraction dose was escalated from 4 Gy to 7 Gy, of which contents were as follows 4 Gy/f x 10 f (one) 4 Gy/fx 12 f (one), 4 Gy/fx 15 f (one), 5 Gy/fx 10 f (3) 5 Gy/f x 12 f (3), 6 Gy x 10 f (3), and 7 Gy/f x 10 f (one). Total dose by LQ model were estimated as 56-119 in BEDacute (α/β=10), and 120-315 in BEDlate (α/β=3). V20 ranged from 2.52-10.24% (average 5.84). In the initial response, 8 lesions were achieved as CR, 2 as PR and 3 as SD. Among 13 lesions, no lesion had re-growth. Radiation-induced pulmonary complications greater than National Cancer Institute (NCI)-CTC criteria Grade 2 was noted one only. In change of CT image, slight increase in opacity was noted 3 cases within 3 month after treatment. Pachy consolidation was noted 10 cases between 3 month and 12 month after treatment. Stereotactic radiation therapy by medium fraction size for lung tumor was considered as effective and safety. (author)

  19. Determination of lesion size by ultrasound during radiofrequency catheter ablation.

    Science.gov (United States)

    Awad, S; Eick, O

    2003-01-01

    The catheter tip temperature that is used to control the radiofrequency generator output poorly correlates to lesion size. We, therefore, evaluated lesions created in vitro using a B-mode ultrasound imaging device as a potential means to assess lesion generation during RF applications non-invasively. Porcine ventricular tissue was immersed in saline solution at 37 degrees C. The catheter was fixed in a holder and positioned in a parallel orientation to the tissue with an array transducer (7.5 MHz) app. 3 cm above the tissue. Lesions were produced either in a temperature controlled mode with a 4-mm tip catheter with different target temperatures (50, 60, 70 and 80 degrees C, 80 W maximum output) or in a power controlled mode (25, 50 and 75 W, 20 ml/min irrigation flow) using an irrigated tip catheter. Different contact forces (0.5 N, 1.0 N) were tested, and RF was delivered for 60 s. A total of 138 lesions was produced. Out of these, 128 could be identified on the ultrasound image. The lesion depth and volume was on average 4.1 +/- 1.6 mm and 52 +/- 53 mm3 as determined by ultrasound and 3.9 +/- 1.7 mm and 52 +/- 55 mm3 as measured thereafter, respectively. A linear correlation between the lesion size determined by ultrasound and that measured thereafter was demonstrated with a correlation coefficient of r = 0.87 for lesion depth and r = 0.93 for lesion volume. We conclude that lesions can be assessed by B-mode ultrasound imaging. PMID:12910859

  20. Smart Procurement of Naturally Generated Energy (SPONGE) for Plug-in Hybrid Electric Buses

    OpenAIRE

    Naoum-Sawaya, Joe; Crisostomi, Emanuele; Liu, Mingming; Gu, Yingqi; Shorten, Robert

    2016-01-01

    We discuss a recently introduced ECO-driving concept known as SPONGE in the context of Plug-in Hybrid Electric Buses (PHEB)'s.Examples are given to illustrate the benefits of this approach to ECO-driving. Finally, distributed algorithms to realise SPONGE are discussed, paying attention to the privacy implications of the underlying optimisation problems.

  1. Transportation of Wheelchair Seated Students in School Buses: A Review of State Policy

    Science.gov (United States)

    Moore, Britta; Fuhrman, Susan; Karg, Patricia

    2010-01-01

    This study quantitatively reviews publicly available state policies as they relate to the transportation of wheelchair-seated students in school buses. Inclusion of best practices in specially equipped school bus and driver training policies was assessed. Key points of interest within state policies were identified based on site visits, common…

  2. Carbon Dioxide Concentrations and Temperatures within Tour Buses under Real-Time Traffic Conditions.

    Directory of Open Access Journals (Sweden)

    Chun-Fu Chiu

    Full Text Available This study monitored the carbon dioxide (CO2 concentrations and temperatures of three 43-seat tour buses with high-passenger capacities in a course of a three-day, two-night school excursion. Results showed that both driver zones and passenger zones of the tour buses achieved maximum CO2 concentrations of more than 3000 ppm, and maximum daily average concentrations of 2510.6 and 2646.9 ppm, respectively. The findings confirmed that the CO2 concentrations detected in the tour buses exceeded the indoor air quality standard of Taiwan Environmental Protection Administration (8 hr-CO2: 1000 ppm and the air quality guideline of Hong Kong Environmental Protection Department (1 hr-CO2: 2500 ppm for Level 1 for buses. Observations also showed that high-capacity tour bus cabins with air conditioning system operating in recirculation mode are severely lacking in air exchange rate, which may negatively impact transportation safety. Moreover, the passenger zones were able to maintain a temperature of between 20 and 25°C during travel, which effectively suppresses the dispersion of volatile organic compounds. Finally, the authors suggest that in the journey, increasing the ventilation frequency of tour bus cabin, which is very beneficial to maintain the travel safety and enhance the quality of travel.

  3. An introduction on the demonstration performance of fuel cell buses (FCB) in Beijing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Since the 1990’s, hydrogen has found broad use in the traffic segment. Compared with conventional ones, hydrogen fuelled vehicles, a new generation of clean vehicles, produce no pollutants, with higher energy efficiency. In today’s world where the pollution is tougher, the "Zero Pollution" fuel cell buses display a

  4. BIODIESEL AS A SUSTAINABLE ALTERNATIVE TO PETROLEUM DIESEL IN SCHOOL BUSES

    Science.gov (United States)

    Diesel exhaust is potentially harmful to human health and is a significant air pollutant due to its composition of harmful chemical substances and impact on climate. One of the many current uses of diesel fuel in rural environments is in school buses; however, few studies hav...

  5. Lignin profiling in extracted xylans by size-exclusion chromatography.

    Science.gov (United States)

    Hutterer, Christian; Schild, Gabriele; Kliba, Gerhard; Potthast, Antje

    2016-10-20

    Utilization of the polymeric parts of lignocellulose is expected to gain increasing importance in future biorefinery scenarios. In that respect, a particular focus is placed on hemicelluloses from different wood species gained from an industrially feasible upgrading step in the production of dissolving pulps from paper pulps. During alkaline post-extractions for hemicellulose removal, residual lignins are extracted as well. They are either covalently linked to the extracted hardwood xylans or simply co-dissolved in the alkaline lye. In order to better describe the lignin in xylan containing lyes, a method for lignin profiling was set up by hyphenating size-exclusion chromatography of xylans with UV detection which facilitates visualization of the residual lignin distribution. Simultaneous lignin quantification was achieved with lignin standards prepared from Kraft cooking liquors. The setup presented may serve as advanced characterization for novel xylan products. PMID:27474629

  6. Functional size analysis of bioactive materials by radiation inactivation

    International Nuclear Information System (INIS)

    When the research on various proteins including enzymes is carried out, first molecular weight is measured. The physical chemical methods used for measuring molecular weight cannot measure it in the state of actually acting in living bodies. Radiation inactivation method is the unique method which can measure the molecular weight of the active substances in living bodies. Paying attention to this point, recently it is attempted to measure the activity unit of enzymes, receptors and others, and to apply to the elucidation of their functions. In this report, the concept of the method of measuring molecular size based on radiation inactivation, the detailed experimental method and the points to which attention must be paid are described. Also its application to the elucidation of living body functions according to the example of the studies by the author is reported. The concept of the measurement of molecular weight by radiation inactivation is based on target theory. The preparation of samples, the effect of oxygen, radiation sources, dosimetry, irradiation temperature, internal standard process and so on are reported. The trend of the research is shown. (K.I.)

  7. Restrictions to protein folding determined by the protein size.

    Science.gov (United States)

    Finkelstein, Alexei V; Bogatyreva, Natalya S; Garbuzynskiy, Sergiy O

    2013-06-27

    Experimentally measured rates of spontaneous folding of single-domain globular proteins range from microseconds to hours: the difference (11 orders of magnitude!) is akin to the difference between the life span of a mosquito and the age of the Universe. We show that physical theory with biological constraints outlines the possible range of folding rates for single-domain globular proteins of various size and stability, and that the experimentally measured folding rates fall within this narrow "golden triangle" built without any adjustable parameters, filling it almost completely. This "golden triangle" also successfully predicts the maximal allowed size of the "foldable" protein domains, as well as the maximal size of protein domains that fold under solely thermodynamic (rather than kinetic) control. In conclusion, we give a phenomenological formula for dependence of the folding rate on the size, shape and stability of the protein fold. PMID:23684724

  8. Size Controlled Synthesis of Starch Nanoparticles by a Microemulsion Method

    OpenAIRE

    2014-01-01

    Controllable particles sizes of starch nanoparticles were synthesized via a precipitation in water-in-oil microemulsion approach. Microemulsion method offers the advantages of ultralow interfacial tension, large interfacial area, and being thermodynamically stable and affords monodispersed nanoparticles. The synthesis parameters such as stirring rates, ratios of oil/cosurfactant, oil phases, cosurfactants, and ratios of water/oil were found to affect the mean particle size of starch nanoparti...

  9. Size determination of Streptococcus mutans 10499 by laser light scattering.

    OpenAIRE

    Ryan, V; Hart, T R; Schiller, R

    1980-01-01

    We have performed three different optical experiments to determine the mean size of the bacterial strain Streptococcus mutans 10449, a microorganism with dimensions comparable to the wavelength of the light used in our experiments. The three optical measurements give size values which are consistent with one another and favorably comparable to the consistency we found in identical measurements on a test system of polystyrene spheres of dimensions similar to the bacteria. Homodyne time correla...

  10. Effects of impurities on particle sizing by acoustic attenuation spectroscopy

    OpenAIRE

    Inam, Muhammad Asif; Frances, Christine

    2010-01-01

    It is important to have correct information regarding particle size in order to interpret, control, and optimize many industrial processes. Prior to the recent advent of acoustic attenuation spectroscopy, it was difficult to study particle size distribution online and under real process conditions in processes involving concentrated dispersions (suspensions or emulsions). The technique still needs improvement because it is less known how and under which conditions to employ the technique when...

  11. Synthesis of nano sized solid catalysts assisted by microwaves irradiation

    International Nuclear Information System (INIS)

    Full text: In our preceding works the correlation between physico-chemical surface properties and the catalytic results obtained have been clearly evidenced. Some of these properties are strongly connected with the size of the particles constituting the catalyst. In particular the nano particle role on the catalytic behaviour has been evidenced. The fundamental parameters for the preparation of nano particles are: a) the control of the nucleation rate and the growth rate b) the homogeneous nucleation. This control is particularly difficult when using conventional preparation method. The use of microwave allows a better control of such processes in order to obtain a rapid nucleation followed by a controllable growth. The results obtained were particularly interesting since they evidenced a) a homogeneous and fast nucleation, b) a successive slow growth of the particle controllable by means of microwaves which can stop the heating of the reaction medium instantaneously and c) a successive nucleation prevented by the low supersaturation of the remaining value. The preparation of a nano sized catalyst demands a sequence of unit operations that are connected with each other as the parameter optimisation at the basis of each stage of the preparation determines the properties of the final catalyst. In this work microwaves have been employed at all stages of the catalyst preparation and at every stage there evidence of beneficial effects from the Microwave heating compared to conventional methods. For instance ZrO2 exhibits interesting catalytic actions for some organic industrial reactions. These reactions have been found to be sensitive to structure, acidity, surface area and porosity. Zirconium precursors preparation involved several methods, among them the precipitation in basic or acid medium. The first method involve the precipitation of zirconium hydroxide starting from ZrOCl2. Samples were prepared by dissolving ZrOCl2 hi distilled water under continuous stirring

  12. Electronic structure and size of TiO sub 2 nanoparticles of controlled size prepared by aerosol methods

    CERN Document Server

    Soriano, L; Sanchez-Agudo, M; Sanz, J M; Ahonen, P P; Kauppinen, E I; Palomares, F J; Bressler, P R

    2002-01-01

    A complete characterization of nanostructures has to deal both with electronic structure and dimensions. Here we present the characterization of TiO sub 2 nanoparticles of controlled size prepared by aerosol methods. The electronic structure of these nanoparticles was probed by x-ray absorption spectroscopy (XAS), the particle size by atomic force microscopy (AFM). XAS spectra show that the particles crystallize in the anatase phase upon heating at 500 sup o C, whereas further annealing at 700 sup o C give crystallites of 70 % anatase and 30 % rutile phases. Raising the temperature to 900 sup o C results in a complete transformation of the particles to rutile. AFM images reveal that the mean size of the anatase particles formed upon heating at 500 sup o C is 30 nm, whereas for the rutile particles formed upon annealing at 900 sup o C 90 nm were found. The results obtained by these techniques agree with XRD data. (author)

  13. Etude expérimentale de l'atomisation des sprays agricoles : buse à turbulence et buse anti-dérive

    OpenAIRE

    Vallet, A.

    2010-01-01

    / En comparaison à la pollution des eaux, la pollution de l'air par les pesticides est encore une préoccupation émergente. Or, une grande partie des pesticides contamine l'air, notamment lors de leur application. La quantité et la façon dont les pesticides arrivent dans l'air sont fortement dépendantes de la taille et de la vitesse des gouttes en sortie de buse. En effet, bien que les plus petites gouttes soient indispensables à une bonne couverture du végétal ciblé, il est clair que celles-c...

  14. MONODISPERSE MICRON-SIZED POLYACRYLAMIDE PARTICLES SYNTHESIZED BY DISPERSION POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Xin Hou; Bo Gao; Zhe-guo Zhang; Kang-de Yao

    2007-01-01

    Monodisperse micron-sized polyacrylamide (PAM) particles with a regular shape have been successfully prepared through dispersion polymerization of the monomer using a rotary reactor. FTIR and NMR spectroscopic results demonstrated the formation of PAM. POM and TEM observations revealed that PAM particles had a regular shape and good dispersity. A thick layer of surfactant (PVP) still existed on PAM particles after multiple centrifugation and ultrasonic re-dispersion in ethanol, which indicates a strong interaction between PVP and PAM. The effects of various polymerization factors on the average size of PAM particles have also been studied.

  15. Preliminary study on field buses for the control system of the high voltage of the ATLAS hadronic calorimeter

    International Nuclear Information System (INIS)

    We present here after a preliminary study on field buses for the control system of the high voltage of the photomultipliers of the TILECAL calorimeter. After some generalities, different commercial buses are reviewed (CAN, ARCET, WorldFIP, Profibus and LonWorks). The Profibus and LonWorks solution are more extensively studies as a possible solution for the high voltage system of the TILE hadronic calorimeter. (authors)

  16. Development and demonstration of use of methane/hydrogen blends as fuel in existing methane-driven buses; Utveckling och demonstration av anvaendning av metan/vaetgasblandningar som braensle i befintliga metangasdrivna bussar

    Energy Technology Data Exchange (ETDEWEB)

    Joensson, Owe

    2006-10-15

    Two natural gas buses in Malmoe have in a project been converted to run on mixtures of hydrogen and natural gas. The buses have been in operation from September 2003 to December 2005 and have during the whole extent of the project been in commercial operation with passengers. One bus has been refuelled with a mixture containing 8% hydrogen and another with 25% hydrogen. One of the buses has during limited periods been refuelled with natural gas in order to establish differences in fuel consumption between the different fuels. A number of different supporting activities have been performed in conjunction to the project: Tests at the Lund Univ. with hydrogen addition to natural gas in a one cylinder test engine and in a 6 cylinder natural gas engine. Safety analysis for handling of hydrogen/natural gas blends. Hydrogen compatibility study of material and components in bus fuel system. Test of leak detection systems for hydrogen and hydrogen/natural gas blends. Development of safety routines for operation and maintenance staff. Emission measurement during road operation with mobile equipment. Follow up of filling station for hydrogen/natural gas blends. The results from the projects are: The buses did not need to be modified in any way in order to run on mixtures with up to 8 vol-% hydrogen. The buses could, in less than 4 h, be modified to run on mixtures with 25 vol-% hydrogen. The conversion was accomplished by changing one computer chip in the engine control system, thus altering the air/fuel ratio and adjusting the ignition angle. The fuel consumption of the buses was reduced by 20-30% by hydrogen addition. The largest relative influence was achieved with 8% hydrogen addition. The reduced fuel consumption in combination with reduced carbon content in the fuel resulted in a total reduction in CO{sub 2}-emission by approximately 35% using 8% hydrogen (by volume). Addition of hydrogen to natural gas has thus proved to be a more efficient way of reducing CO{sub 2

  17. New concept for the ground connection in Scania’s trucks and buses

    OpenAIRE

    LLORENTE, ANDRÉS

    2014-01-01

    Regarding the ground electrical connection in trucks and buses, the requirements of earthing in heavy-duty vehicles were gathered and evaluated. The most important problems in the state-of-the-art grounding devices are corrosion, electrical resistance and uncertainty in the mounting process, altogether with depreciation over time. The goal is to come up with new concepts that can give a more reliable and better ground connection into the frame with faster, easier and safer manufacturing opera...

  18. Long Beach Transit: Two-Year Evaluation of Gasoline-Electric Hybrid Transit Buses

    Energy Technology Data Exchange (ETDEWEB)

    Lammert, M.

    2008-06-01

    This report focuses on a gasoline-electric hybrid transit bus propulsion system. The propulsion system is an alternative to standard diesel buses and allows for reductions in emissions (usually focused on reductions of particulate matter and oxides of nitrogen) and petroleum use. Gasoline propulsion is an alternative to diesel fuel and hybrid propulsion allows for increased fuel economy, which ultimately results in reduced petroleum use.

  19. Comparison of Life Cycle energy consumption and GHG emissions of natural gas, biodiesel and diesel buses of the Madrid transportation system

    International Nuclear Information System (INIS)

    This paper presents a comparative study on the use of three after-treatment technologies: i) EGR + DPF, ii) SCR + Urea and iii) 3-way catalyst when implemented in urban buses, to determinate the energy requirements, greenhouse gas emissions (GHG), direct Land Use Change (dLUC), abiotic depletion of fossil energy by means of a Life Cycle Assessment (LCA). The process of production, conditioning and transporting of the fuels used by the buses (diesel, biodiesel (B100), a blended biodiesel at 20% (B20) and natural gas) were also analyzed (Well-to-Tank analysis) along with the environmental impact due to its combustion in the bus (Tank-to-Wheel analysis). The environmental impact of the manufacturing, maintenance and recycling process of the urban buses and exhaust after-treatment systems has also been evaluated. Main results shows that Life Cycle of SCR + Urea technology reduces environmental impact to a greater extent than its global Life Cycle increases it when gasoil is used resulting in a final balance more efficient than the other options, the same behavior is observed with the use of B20 and B100 but only when 0%dLUC is assumed since if the percentage of dLUC increases the effectiveness of the SCR + Urea technology in the reduction of environmental impact tend to decrease. -- Highlights: ► We examine the environmental impact caused by the Life Cycle of each technology, fossil fuel, biofuel and vehicle. ► Biodiesel environmental impact depends largely on land transformed for grow crops. ► Using SCR + Urea technology and gasoil as a fuel in the bus further reduces the environmental impact.

  20. Molecular weight analysis by size exclusion chromatography with multiple detection

    Czech Academy of Sciences Publication Activity Database

    Netopilík, Miloš

    Bangalore : Central Power Research Institute, 2007, s. 1-6. [International Conference on Polymeric Materials in Power Engineering. Bangalore (IN), 04.10.2007-06.10.2007] R&D Projects: GA AV ČR IAA400500703; GA ČR GA203/07/0659 Institutional research plan: CEZ:AV0Z40500505 Keywords : size exclusion chromatography * viscometric detection * number- average molecular weight Subject RIV: CF - Physical ; Theoretical Chemistry

  1. Analysis of cipher text size produced by various Encryption Algorithms

    Directory of Open Access Journals (Sweden)

    MANI ARORA

    2011-07-01

    Full Text Available In the digital world, it is the need of the hour to secure the data communication from unauthorized access. Over the time a number of techniques and algorithms have came into operation for its security. This research paper is done qualitatively to emphasize the need for securing the data as well as the fast transmission of the encryptedtext. It concerns the analysis of selected symmetric cipher block encryption algorithms from cipher text size point of view.

  2. Thermal conductivity of graphene mediated by strain and size

    OpenAIRE

    Kuang, Youdi; Lindsay, Lucas; Shi, Sanqiang; Wang, Xinjiang; Guo, Ruiqiang; Huang, Baoling

    2015-01-01

    Based on first-principles calculations and full iterative solution of the linearized Boltzmann-Peierls transport equation for phonons within three-phonon scattering framework, we characterize the lattice thermal conductivities $\\kappa$ of strained and unstrained graphene. We find $\\kappa$ converges to 5450 W/m-K for infinite unstrained graphene, while $\\kappa$ diverges for strained graphene with increasing system size at room temperature. The different $\\kappa$ behaviors for these systems are...

  3. Simple and cost-effective fabrication of size-tunable zinc oxide architectures by multiple size reduction technique

    Directory of Open Access Journals (Sweden)

    Hyeong-Ho Park, Xin Zhang, Seon-Yong Hwang, Sang Hyun Jung, Semin Kang, Hyun-Beom Shin, Ho Kwan Kang, Hyung-Ho Park, Ross H Hill and Chul Ki Ko

    2012-01-01

    Full Text Available We present a simple size reduction technique for fabricating 400 nm zinc oxide (ZnO architectures using a silicon master containing only microscale architectures. In this approach, the overall fabrication, from the master to the molds and the final ZnO architectures, features cost-effective UV photolithography, instead of electron beam lithography or deep-UV photolithography. A photosensitive Zn-containing sol–gel precursor was used to imprint architectures by direct UV-assisted nanoimprint lithography (UV-NIL. The resulting Zn-containing architectures were then converted to ZnO architectures with reduced feature sizes by thermal annealing at 400 °C for 1 h. The imprinted and annealed ZnO architectures were also used as new masters for the size reduction technique. ZnO pillars of 400 nm diameter were obtained from a silicon master with pillars of 1000 nm diameter by simply repeating the size reduction technique. The photosensitivity and contrast of the Zn-containing precursor were measured as 6.5 J cm−2 and 16.5, respectively. Interesting complex ZnO patterns, with both microscale pillars and nanoscale holes, were demonstrated by the combination of dose-controlled UV exposure and a two-step UV-NIL.

  4. Standard guide for planar flaw height sizing by ultrasonics

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This guide provides tutorial information and a description of the principles and ultrasonic examination techniques for measuring the height of planar flaws which are open to the surface. The practices and technology described in this standard guide are intended as a reference to be used when selecting a specific ultrasonic flaw sizing technique as well as establishing a means for instrument standardization. 1.2 This standard guide does not provide or suggest accuracy or tolerances of the techniques described. Parameters such as search units, examination surface conditions, material composition, etc. can all have a bearing on the accuracy of results. It is recommended that users assess accuracy and tolerances applicable for each application. 1.3 This document does not purport to provide instruction to measure flaw length. 1.4 This standard guide does not provide, suggest, or specify acceptance standards. After flaw-sizing evaluation has been made, the results should be applied to an appropriate code or...

  5. Poeciliid male mate preference is influenced by female size but not by fecundity

    Directory of Open Access Journals (Sweden)

    Luis R. Arriaga

    2013-08-01

    Full Text Available While female mate preference is very well studied, male preference has only recently begun to receive significant attention. Its existence is found in numerous taxa, but empirical research has mostly been limited to a descriptive level and does not fully address the factors influencing its evolution. We attempted to address this issue using preference functions by comparing the strength of male preference for females of different sizes in nine populations of four poeciliid species. Due to environmental constraints (water toxicity and surface versus cave habitat, females from these populations vary in the degree to which their size is correlated to their fecundity. Hence, they vary in how their size signals their quality as mates. Since female size is strongly correlated with fecundity in this subfamily, males were sequentially presented with conspecific females of three different size categories and the strength of their preference for each was measured. Males preferred larger females in all populations, as predicted. However, the degree to which males preferred each size category, as measured by association time, was not correlated with its fecundity. In addition, cave males discriminated against smaller females more than surface males. Assuming that male preference is correlated with female fitness, these results suggest that factors other than fecundity have a strong influence on female fitness in these species.

  6. Towards sustainable urban transportation: Test, demonstration and development of fuel cell and hybrid-electric buses

    International Nuclear Information System (INIS)

    Several aspects make today's transport system non-sustainable: - Production, transport and combustion of fossil fuels lead to global and local environmental problems. - Oil dependency in the transport sector may lead to economical and political instability. - Air pollution, noise, congestion and land-use may jeopardise public health and quality of life, especially in urban areas. In a sustainable urban transport system most trips are made with public transport because high convenience and comfort makes travelling with public transport attractive. In terms of emissions, including noise, the vehicles are environmentally sustainable, locally as well as globally. Vehicles are energy-efficient and the primary energy stems from renewable sources. Costs are reasonable for all involved, from passengers, bus operators and transport authorities to vehicle manufacturers. The system is thus commercially viable on its own merits. This thesis presents the results from three projects involving different concept buses, all with different powertrains. The first two projects included technical evaluations, including tests, of two different fuel cell buses. The third project focussed on development of a series hybrid-bus with internal combustion engine intended for production around 2010. The research on the fuel cell buses included evaluations of the energy efficiency improvement potential using energy mapping and vehicle simulations. Attitudes to hydrogen fuel cell buses among passengers, bus drivers and bus operators were investigated. Safety aspects of hydrogen as a vehicle fuel were analysed and the use of hydrogen compared to electrical energy storage were also investigated. One main conclusion is that a city bus should be considered as one energy system, because auxiliaries contribute largely to the energy use. Focussing only on the powertrain is not sufficient. The importance of mitigating losses far down an energy conversion chain is emphasised. The Scania hybrid fuel cell

  7. Does Size Matter? The Underlying Intrinsic Size Distribution of Radio Sources and Implications for Unification by Orientation

    CERN Document Server

    DiPompeo, Michael A; Myers, Adam D; Boroson, Todd A

    2013-01-01

    Unification by orientation is a ubiquitous concept in the study of active galactic nuclei. A gold standard of the orientation paradigm is the hypothesis that radio galaxies and radio-loud quasars are intrinsically the same, but are observed over different ranges of viewing angles. Historically, strong support for this model was provided by the projected sizes of radio structure in luminous radio galaxies, which were found to be significantly larger than those of quasars, as predicted due to simple geometric projection. Recently, this test of the simplest prediction of orientation-based models has been revisited with larger samples that cover wider ranges of fundamental properties---and no clear difference in projected sizes of radio structure is found. Cast solely in terms of viewing angle effects, these results provide convincing evidence that unification of these objects solely through orientation fails. However, it is possible that conflicting results regarding the role orientation plays in our view of rad...

  8. Onset of size independent cationic exchange in nano-sized CoFe2O4 induced by electronic excitation

    International Nuclear Information System (INIS)

    Highlights: • Electronic excitation induced crystalline order in CoFe2O4. • No change of metallic valence state under dense electronic excitation. • Size independent control of cations in CoFe2O4. - Abstract: Present work investigates electronic excitation induced cationic exchange phenomena in nano-sized cobalt ferrites using Mössabaur and X-ray absorption spectroscopies. The electronic excitations were produced by irradiation of 100 MeV O+7 at different fluences ranging from 1 × 1011 to 1 × 1014 ions/cm2. Cubic spinel phase of cobalt ferrite remains preserved after irradiation. However, attributes of crystalline disorder were observed in irradiated materials. Crystallite size remain almost same for pristine and irradiated materials. X-ray absorption fine structure measurements show the preservation of valence state and spin state of metal ions under intense electronic excitation. These measurements also envisage bond breaking process induced by the electronic excitation. Mössbauer spectroscopic measurements also corroborate with the fine structure measurements that the valence state of Fe remains same after irradiation. Paramagnetic doublet which presents in the Mössabaur spectrum of pristine material disappears after irradiation, showing the evolution of irradiation induced magnetic ordering. Fe3+ ion increases with irradiation at octahedral site of spinel lattice. Magnetization of the material slightly increases after irradiation at the fluence of 5 × 1013 and 1 × 1014 ions/cm2

  9. Determination of Size Distribution of Nano-particles by Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Yan XUE; Hai Ying YANG; Yong Tan YANG

    2005-01-01

    A new method was developed for the determination of the size distribution of nano-particles by capillary zone electrophoresis (CZE). Scattering effect of nanoparticles was studied. This method for the determination of size distribution was statistical.

  10. Preparation of Nano-Sized TiO2 Particles by Microemulsion Method

    Institute of Scientific and Technical Information of China (English)

    Shaohua Zhang; Bing Xie; Fengyi Li; Peng Xu

    2006-01-01

    Nano-sized titania powders have been prepared by hydrolysis of tetrabutyl titanate in the droplet of water/OP-7/pentanol/cyclohexane microemulsion system. The effects of ingredient change on the water drop size and particle size were investigated. The prepared TiO2 was in the form of anatase after annealing. TiO2 was characterized by TG-TGA,FTIR, XRD to measure the transformation temperature, surface adsorption and average size.

  11. Numerical simulation of grain-size effects on creep crack growth by means of grain elements

    International Nuclear Information System (INIS)

    The effect of grain size on creep crack growth is investigated by means of a numerical technique in which the actual crack growth process is simulated in a discrete manner by grain elements and grain boundary elements. The grain elements account for the creep deformation of individual grains, while grain boundary cavitation and sliding are accounted for by grain boundary elements between the grains. This grain-element technique allows for an independent study of multiple grain size effects: a (direct) size effect related to the specimen size/grain size ratio or an (indirect) effect related to the effect of grain size on nucleation rate and creep resistance. Preliminary numerical results are presented concerning the direct effect of grain size, which predict that the crack growth rate and brittleness increase with grain size. (orig.)

  12. Determination of Size Distributions in Nanocrystalline Powders by TEM, XRD and SAXS

    DEFF Research Database (Denmark)

    Jensen, Henrik; Pedersen, Jørgen Houe; Jørgensen, Jens Erik;

    2006-01-01

    Crystallite size distributions and particle size distributions were determined by TEM, XRD, and SAXS for three commercially available TiO2 samples and one homemade. The theoretical Guinier Model was fitted to the experimental data and compared to analytical expressions. Modeling of the XRD spectra...... the size distribution obtained from the XRD experiments; however, a good agreement was obtained between the two techniques. Electron microscopy, SEM and TEM, confirmed the primary particle sizes, the size distributions, and the shapes obtained by XRD and SAXS. The SSEC78 powder and the commercially...... showed a difference between the analytical size dependent expressions and the theoretical Guinier Model. Primay particle size distributions were extracted from SAXS measurements by the hard sphere model including the interparticle interference factor. The size distributions from SAXS were smaller than...

  13. At what extent the benefits of introducing alternative light-duty vehicles offset those of increasing the buses average occupancy?

    International Nuclear Information System (INIS)

    Highlights: • Characterization of fuel consumption, emissions and daily distance, of road fleet by probability distribution functions. • The co-benefit of congestion level decrease due to mode-shifting from LDV to bus is explored. • A potential decrease in NOx + PM of 23% is foreseen, by 50% LDV replacement or mode-shifting (bus occupancy 40–80%). • A decrease of CO2 is foreseen as being 20%, by 50% LDV replacement or mode-shifting (bus occupancy 30–60%). • Electricity mix relaying on renewables will increase the window were the energy and CO2 benefits match to 35%. - Abstract: This paper quantifies the energy and emissions benefits of introducing electric drive vehicles (pure electric, plug-in hybrid and fuel cell) on a conventional light-duty fleet (LDV) versus promoting the intensification of the public transportation use by means of mode-shifting and increased average bus occupancy. The impact is assessed in terms of energy, local pollutants, HC, CO, NOx, PM, and global emissions of CO2. The specific fleet of Portugal is used as case study. This fleet has roughly 6 million LDV (30% diesel, 70% gasoline) and 15,000 buses, with a mobility indicator of 106 thousand million passengerxkm (pkm). Probability density functions for energy consumption and emissions are derived for conventional, electric drive vehicles, and buses, avoiding considering one representative vehicle of each. Scenarios of 30–50% conventional fleet replacement is compared against scenarios of bus occupancy increase from 20% to 80%. The increased bus occupancy is made by mode-shifting from conventional LDV vehicles keeping the mobility pkm and bus supply. The co-benefit of congestion level decrease due to mode-shifting is explored. The effect of different electricity mixes is also analyzed. The methodology used allowed obtaining likelihood functions for energy consumption and emissions for each scenario and offset areas where the benefits match. The use of the methodology for

  14. Otero County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  15. Santa Fe County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  16. Quay County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  17. Bernalillo County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  18. Dona Ana County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  19. Chaves County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  20. Curry County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  1. San Miguel County Blocks, Average Household Size by Tenure (2010)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The once-a-decade decennial census was conducted in April 2010 by the U.S. Census Bureau. This count of every resident in the United States was mandated by Article...

  2. Direct and Indirect Evidence of Size-Selective Grazing on Pelagic Bacteria by Freshwater Nanoflagellates

    OpenAIRE

    Šimek, Karel; Chrzanowski, Thomas H.

    1992-01-01

    Size-selective grazing of three heterotrophic nanoflagellates (with cell sizes of 21, 44, and 66 μm3) isolated from Lake Arlington, Texas was examined by using a natural mixture of fluorescence labelled lake bacteria. Sizes of ingested bacteria in food vacuoles were directly measured. Larger bacterial cells were ingested at a frequency much higher than that at which they occurred in the assemblage, indicating preferential flagellate grazing on the larger size classes within the lake bacteriop...

  3. Grain and Oilseed Shipment Sizes and Distance Hauled by Rail

    OpenAIRE

    Prater, Marvin; Sparger, Adam

    2013-01-01

    Grain and railroads have an interdependent relationship. Grain is one of the most important commodities for railroads. It is the primary agricultural commodity moved by rail, comprising 7.9 percent by tons of all commodities, 94 percent by tons of all farm commodities, and 8.4 percent of total rail revenue in 2009. In turn, railroads represent a vital component of the grain network, hauling 33 percent of all grain transported in the United States in 2007. As domestic and export markets have e...

  4. The Fuel Economy of Hybrid Buses: The Role of Ancillaries in Real Urban Driving

    OpenAIRE

    Francesco Bottiglione; Tommaso Contursi; Angelo Gentile; Giacomo Mantriota

    2014-01-01

    In the present context of the global economic crisis and environmental emergency, transport science is asked to find innovative solutions to turn traditional vehicles into fuel-saving and eco-friendly devices. In the last few years, hybrid vehicles have been shown to have potential benefits in this sense. In this paper, the fuel economy of series hybrid-electric and hybrid-mechanical buses is simulated in two real driving situations: cold and hot weather driving in the city of Taranto, in Sou...

  5. Laser Mode-Dependent Size of Plasma Zones Induced by Femtosecond Laser Pulses in Fused Silica

    Institute of Scientific and Technical Information of China (English)

    TANG Shan-Chun; JIANG Hong-Bing; LIU Yi; GONG Qi-Huang

    2008-01-01

    We carry out the numerical simulations of #emtosecond laser propagation with TEM00 mode, TEM10 mode and a beam combining both the modes in fused silica. It is found that the transverse size of plasma zones induced by laser pulses with the TEM10 mode is smaller than that induced by the TEMoo mode, while the longitudinal size is almost the same, and the saturated plasma density is higher. The transverse size, the longitudinal size and the ratio of the longitudinal to transverse size, for the beam combining both the modes, all could be reduced at the same time in comparison with the TEMoo mode under the same focusing conditions.

  6. Multidimensional profiling of plasma lipoproteins by size exclusion chromatography followed by reverse-phase protein arrays

    OpenAIRE

    Dernick, Gregor; Obermüller, Stefan; Mangold, Cyrill; Magg, Christine; Matile, Hugues; Gutmann, Oliver; von der Mark, Elisabeth; Handschin, Corinne; Maugeais, Cyrille; Niesor, Eric J.

    2011-01-01

    The composition of lipoproteins and the association of proteins with various particles are of much interest in the context of cardiovascular disease. Here, we describe a technique for the multidimensional analysis of lipoproteins and their associated apolipoproteins. Plasma is separated by size exclusion chromatography (SEC), and fractions are analyzed by reverse-phase arrays. SEC fractions are spotted on nitrocellulose slides and incubated with different antibodies against individual apolipo...

  7. Effect of DOM Size on Organic Micropollutant Adsorption by GAC.

    Science.gov (United States)

    Kennedy, Anthony M; Summers, R Scott

    2015-06-01

    Granular activated carbon (GAC) adsorption of the micropollutants 2-methylisoborneol (MIB) and warfarin (WFN) at ng/L levels was investigated in five waters with isolated natural dissolved organic matter (DOM) held at a constant dissolved organic carbon concentration. Each water was evaluated for competitive adsorption effects based on the pretreatment of ultrafiltration, coagulation, and additional background micropollutants. Using the breakthrough with unfractionated DOM as a baseline, on average, the water with lower molecular weight (MW) DOM decreased MIB and WFN adsorption capacity by 59%, whereas the water with higher MW DOM increased MIB and WFN adsorption capacity by 64%. All waters showed similar decreasing MIB and WFN adsorption capacity with increasing empty bed contact time (EBCT), with more dramatic effects seen for the more strongly adsorbing WFN. On average, MIB and WFN adsorption kinetics were two times slower in the water with higher MW DOM compared to the water with lower MW DOM, as described by the intraparticle pore diffusion tortuosity. Increased adsorption competition from 27 micropollutants other than MIB and WFN at environmentally relevant concentrations had little to no effect on MIB and WFN breakthrough behavior. Any competitive effect from background micropollutants became indiscernible at longer EBCTs. PMID:25955134

  8. An analysis and reduction of disruptive behavior on school buses.

    Science.gov (United States)

    Greene, B F; Bailey, J S; Barber, F

    1981-01-01

    Thousands of children are injured or killed each year in school bus accidents. A significant number of these tragic incidents is precipitated by disruptive child behavior that distracts the drivers from their difficult task. Two experiments were conducted which addressed this problem. For both experiments an automated sound recording device (referred to as a Noise Guard) selectively responsive to frequencies above 500 Hz (i.e., unresponsive to bus drone) recorded both the duration and frequency of noise outbursts above a tolerable threshold. Additionally, an observer made in situ measurements of other disruptions including roughhousing and getting-out-of-seat. In the first experiment, following baseline measurements of these behaviors, middle-school students received feedback for noise outbursts. That is, when "Noise Guard" was activated, it in turn operated one of several lights on a panel visible to all passengers. Each day students were allowed to listen to high-appeal taped music while riding the bus and to participate in a raffle for prizes, provided the number of outbursts on the preceding day remained below a specified criterion indicated on the light panel. This intervention resulted in drastic reductions of noise outbursts with a concomitant reduction in other disruptive behaviors. Comparable results were obtained in the second experiment which eliminated the raffle from the intervention. PMID:7287600

  9. Determination of key dimensions for a glove sizing system by analyzing the relationships between hand dimensions.

    Science.gov (United States)

    Kwon, Ochae; Jung, Kihyo; You, Heecheon; Kim, Hee-Eun

    2009-07-01

    The present study identified key dimensions for the development of a glove sizing system by analyzing the relationships between hand dimensions and demonstrated the construction process of glove sizing systems based on the selected key dimensions. Three hand dimensions (HL: hand length; HC: hand circumference; HB: hand breadth) were selected as the candidates of glove key dimensions by surveying the literature and industry practices of glove sizing systems. Of the key dimension candidates, HL and HC were selected by examining the results of correlation and multiple regression analyses on the 1988 US Army hand anthropometric data. A cross-tabulation of HL and HC with an interval length of 1.3 cm was constructed for each gender and the corresponding lengths and circumferences of cells covering more than 2% of the population were used to provide glove sizing parameters. It was identified that the glove sizing system for males is different from that for females and has more size categories. PMID:18799156

  10. Intriguing structures and magic sizes of heavy noble metal nanoclusters around size 55 governed by relativistic effect and covalent bonding

    International Nuclear Information System (INIS)

    Nanoclusters usually display exotic physical and chemical properties due to their intriguing geometric structures in contrast to their bulk counterparts. By means of first-principles calculations within density functional theory, we find that heavy noble metal PtN nanoclusters around the size N = 55 begin to prefer an open configuration, rather than previously reported close-packed icosahedron or core-shell structures. Particularly, for PtN, the widely supposed icosahedronal magic cluster is changed to a three-atomic-layered structure with D6h symmetry, which can be well addressed by our recently established generalized Wulff construction principle (GWCP). However, the magic number of PtN clusters around 55 is shifted to a new odd number of 57. The high symmetric three-layered Pt57 motif is mainly stabilized by the enhanced covalent bonding contributed by both spin-orbital coupling effect and the open d orbital (5d96s1) of Pt, which result in a delicate balance between the enhanced Pt–Pt covalent bonding of the interlayers and negligible d dangling bonds on the cluster edges. These findings about PtN clusters are also applicable to IrN clusters, but qualitatively different from their earlier neighboring element Os and their later neighboring element Au. The magic numbers for Os and Au are even, being 56 and 58, respectively. The findings of the new odd magic number 57 are the important supplementary of the recently established GWCP

  11. The effect of body size on prey choice by Rivulus luelingi Seegers 1984 (Aplocheiloidei: Rivulidae).

    Science.gov (United States)

    Santos Filho, P de S

    1997-11-01

    The effect of body size of Rivulus luelingi (10-15, 20-25, 30-35, 40-45, 46-50 mm length classes) on predation of three size class combinations of Culex sp larvae (small-medium, small-large, medium-large) was studied in the laboratory by means of analyses of preference, specific overlap, and actual number of prey eaten. The smallest experimental R. luelingi size class (10-15 mm) was gape limited. Experimental diets were affected by prey choice and morphological constraint. Preference for the smaller prey, in each prey type combination, was negatively correlated with predator body size, and the converse was true for the larger prey. Preference for any prey size depended on the available prey distribution. There was a correlation between the number of each prey size eaten and predator size in each prey size combination, except for the small prey in the small-medium combination. Specific overlap analysis revealed asymmetries in diet overlap. Feeding success increased non-linearly with R. luelingi body length for two prey size distributions; longer individuals had a disproportionally high feeding success. Preference analysis was more accurate than either specific overlap or actual number of prey eaten. The three kinds of analysis resulted in blocks of contiguous size classes with similar resource utilization, which were considered to have a high chance of interacting competitively. PMID:9440355

  12. Size speed bias or size arrival effect-How judgments of vehicles' approach speed and time to arrival are influenced by the vehicles' size.

    Science.gov (United States)

    Petzoldt, Tibor

    2016-10-01

    Crashes at railway level crossings are a key problem for railway operations. It has been suggested that a potential explanation for such crashes might lie in a so-called size speed bias, which describes the phenomenon that observers underestimate the speed of larger objects, such as aircraft or trains. While there is some evidence that this size speed bias indeed exists, it is somewhat at odds with another well researched phenomenon, the size arrival effect. When asked to judge the time it takes an approaching object to arrive at a predefined position (time to arrival, TTA), observers tend to provide lower estimates for larger objects. In that case, road users' crossing decisions when confronted with larger vehicles should be rather conservative, which has been confirmed in multiple studies on gap acceptance. The aim of the experiment reported in this paper was to clarify the relationship between size speed bias and size arrival effect. Employing a relative judgment task, both speed and TTA estimates were assessed for virtual depictions of a train and a truck, using a car as a reference to compare against. The results confirmed the size speed bias for the speed judgments, with both train and truck being perceived as travelling slower than the car. A comparable bias was also present in the TTA estimates for the truck. In contrast, no size arrival effect could be found for the train or the truck, neither in the speed nor the TTA judgments. This finding is inconsistent with the fact that crossing behaviour when confronted with larger vehicles appears to be consistently more conservative. This discrepancy might be interpreted as an indication that factors other than perceived speed or TTA play an important role for the differences in gap acceptance between different types of vehicles. PMID:27428866

  13. A facile synthesis of Tenanoparticles with binary size distribution by green chemistry

    Science.gov (United States)

    He, Weidong; Krejci, Alex; Lin, Junhao; Osmulski, Max E.; Dickerson, James H.

    2011-04-01

    Our work reports a facile route to colloidal Tenanocrystals with binary uniform size distributions at room temperature. The binary-sized Tenanocrystals were well separated into two size regimes and assembled into films by electrophoretic deposition. The research provides a new platform for nanomaterials to be efficiently synthesized and manipulated.Our work reports a facile route to colloidal Tenanocrystals with binary uniform size distributions at room temperature. The binary-sized Tenanocrystals were well separated into two size regimes and assembled into films by electrophoretic deposition. The research provides a new platform for nanomaterials to be efficiently synthesized and manipulated. Electronic supplementary information (ESI) available: Synthetic procedures, FTIR analysis, ED pattern, AFM image, and EPD current curve. See DOI: 10.1039/c1nr10025d

  14. Effect of pore size on gas resistance of nanofiber membrane by the bubble electrospinning

    Directory of Open Access Journals (Sweden)

    Shen Jing

    2015-01-01

    Full Text Available This paper explores the influence of pore size on gas resistance by comparing micron non-woven and nanofiber membrane. The result shows that membrane with a higher filtration and lower gas resistance can be received by controlling the pore size of nanofiber membrane.

  15. The characteristics of changes in construction companies to become insolvent by size following macroeconomic fluctuations

    OpenAIRE

    Taein Kwon; Sanghyo Lee; Jaejun Kim

    2013-01-01

    In the present study, individual groups of construction companies were first classified according to size, and then the processes of changes needed for them to become insolvent were examined utilizing KMV models. Another objective of the present study was to analyze the relationship between macroeconomic fluctuations and the changes needed for construction companies to become insolvent (based on their size). In the present study, construction companies were classified by size, and the relatio...

  16. Genotype by environment interaction for litter size in pigs as quantified by reaction norms analysis

    DEFF Research Database (Denmark)

    Knap, P W; Su, G

    2008-01-01

    A Bayesian procedure was used to estimate linear reaction norms (i.e. individual G × E plots) on 297 518 litter size records of 121 104 sows, daughters of 2040 sires, recorded on 144 farms in North and Latin America, Europe, Asia and Australia. The method allowed for simultaneous estimation of all...... one to seven litter records, and 0.75 for sires. Hence, including reaction norms in genetic evaluation would increase the reliability of the EBV of young selection candidates without own performance or progeny data by considerably more than 100 × (1/0.75-1) = 33%. Reaction norm slope estimates turn...

  17. Is the public willing to pay for hydrogen buses? A comparative study of preferences in four cities

    Energy Technology Data Exchange (ETDEWEB)

    O' Garra, Tanya [Centre for Environmental Policy, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom)]. E-mail: tanya.ogarra@imperial.ac.uk; Mourato, Susana [Centre for Environmental Policy, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom); Garrity, Lisa [Institute for Sustainability and Technology Policy, Murdoch University, Murdoch 6150, WA (Australia); Schmidt, Patrick [Ludwig-Boelkow-Systemtechnik GmbH, Daimlerstrasse 15, D 85521 Ottobrunn (Germany); Beerenwinkel, Anne [University of Wuppertal, Fachbereich G-Bildungswissenschaften, Lehrstuhl fuer Lehr-, Lern- und Unterrichtsforschung, Gaussstr. 20, 42097 Wuppertal (Germany); Altmann, Matthias [Ludwig-Boelkow-Systemtechnik GmbH, Daimlerstrasse 15, D 85521 Ottobrunn (Germany); Hart, David [Centre for Environmental Policy, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom); Graesel, Cornelia [University of Wuppertal, Fachbereich G-Bildungswissenschaften, Lehrstuhl fuer Lehr-, Lern- und Unterrichtsforschung, Gaussstr. 20, 42097 Wuppertal (Germany); Whitehouse, Simon [Institute for Sustainability and Technology Policy, Murdoch University, Murdoch 6150, WA (Australia)

    2007-07-15

    This paper presents results from the international AcceptH2 study (http://www.accepth2.com) of acceptability and preferences for hydrogen fuel cell (FC) buses. Using the contingent valuation method, this paper compares public willingness to pay (WTP) for the air pollution reductions associated with a scenario of large-scale introduction of hydrogen (H{sub 2}) FC buses in four cities: Berlin, London, Luxembourg and Perth. Results indicate that bus users in all cities have a positive WTP for H{sub 2} buses, and that values (adjusted to the cost of living in each city) are very similar across geographical locations (ranging from WTP an extra Euro 0.29 to Euro 0.35 per single bus fare). Non-bus users were also interviewed in London and Perth, in order to capture values for the whole populations in these cities. Combined results for bus users and non-bus users confirm that overall residents in these cities are willing to pay extra (in taxes) to support the large-scale introduction of H{sub 2}-buses.

  18. Is the public willing to pay for hydrogen buses? A comparative study of preferences in four cities

    Energy Technology Data Exchange (ETDEWEB)

    O' Garra, Tanya; Mourato, Susana; Hart, David [Centre for Environmental Policy, Imperial College London, South Kensington Campus, London SW7 2BP (United Kingdom); Garrity, Lisa; Whitehouse, Simon [Institute for Sustainability and Technology Policy, Murdoch University, Murdoch 6150, WA (Australia); Schmidt, Patrick; Altmann, Matthias [Ludwig-Boelkow-Systemtechnik GmbH, Daimlerstrasse 15, D 85521 Ottobrunn (Germany); Beerenwinkel, Anne; Graesel, Cornelia [University of Wuppertal, Fachbereich G - Bildungswissenschaften, Lehrstuhl fuer Lehr-, Lern- und Unterrichtsforschung,Gaussstr. 20, 42097 Wuppertal (Germany)

    2007-07-15

    This paper presents results from the international AcceptH2 study (http://www.accepth2.com) of acceptability and preferences for hydrogen fuel cell (FC) buses. Using the contingent valuation method, this paper compares public willingness to pay (WTP) for the air pollution reductions associated with a scenario of large-scale introduction of hydrogen (H{sub 2}) FC buses in four cities: Berlin, London, Luxembourg and Perth. Results indicate that bus users in all cities have a positive WTP for H{sub 2} buses, and that values (adjusted to the cost of living in each city) are very similar across geographical locations (ranging from WTP an extra EUR0.29 to EUR0.35 per single bus fare). Non-bus users were also interviewed in London and Perth, in order to capture values for the whole populations in these cities. Combined results for bus users and non-bus users confirm that overall residents in these cities are willing to pay extra (in taxes) to support the large-scale introduction of H{sub 2}-buses. (author)

  19. Is the public willing to pay for hydrogen buses? A comparative study of preferences in four cities

    International Nuclear Information System (INIS)

    This paper presents results from the international AcceptH2 study (http://www.accepth2.com) of acceptability and preferences for hydrogen fuel cell (FC) buses. Using the contingent valuation method, this paper compares public willingness to pay (WTP) for the air pollution reductions associated with a scenario of large-scale introduction of hydrogen (H2) FC buses in four cities: Berlin, London, Luxembourg and Perth. Results indicate that bus users in all cities have a positive WTP for H2 buses, and that values (adjusted to the cost of living in each city) are very similar across geographical locations (ranging from WTP an extra Euro 0.29 to Euro 0.35 per single bus fare). Non-bus users were also interviewed in London and Perth, in order to capture values for the whole populations in these cities. Combined results for bus users and non-bus users confirm that overall residents in these cities are willing to pay extra (in taxes) to support the large-scale introduction of H2-buses

  20. MEASURING OF X-RAY SOURCE SIZE BY USING COMPOUND REFRACTIVE X-RAY LENS

    Directory of Open Access Journals (Sweden)

    Yu. V. Dudchik

    2015-04-01

    Full Text Available Compound refractive lens was used for measuring size of 2-3 beamline Standford synchrotron radiation source and a size of microfocus X-ray tube. X-ray beam from the source was focused by the lens and parameters of the beam at image plane were measured. Scanning diaphragm and X-ray CCD-camera were used for measuring X-ray beam. It was found that the vertical size of synchrotron source is equal to 0,6 mm and the size of the X-ray tube focal spot is equal to 60 micrometers. 

  1. Machining with micro-size single crystalline diamond tools fabricated by a focused ion beam

    International Nuclear Information System (INIS)

    A study was carried out to understand the physics of micro-scale mechanical machining (henceforth referred to as 'micro-machining') with a micro-size tool using a five-axis ultra-precision machine. A micro-size single crystalline diamond (SCD) tool with sharp cutting edges fabricated by a focused ion beam (FIB) was employed to orthogonal-machine four materials (three polycrystalline metals with various grain sizes and one amorphous metal plating material). Since the wealth of knowledge of macro-machining cannot be successfully used in micro-machining, this study contributes to the understanding of the physics of mechanical machining with micro-size tools

  2. Size-controllable synthesis of bare gold nanoparticles by femtosecond laser fragmentation in water

    International Nuclear Information System (INIS)

    We report a size-controllable synthesis of stable aqueous solutions of ultrapure low-size-dispersed Au nanoparticles by methods of femtosecond laser fragmentation from preliminary formed colloids. Such approach makes possible the tuning of mean nanoparticle size between a few nm and several tens of nm under the size dispersion lower than 70% by varying the fluence of pumping radiation during the fragmentation procedure. The efficient size control is explained by 3D geometry of laser fragmentation by femtosecond laser-induced white light super-continuum and plasma-related phenomena. Despite the absence of any protective ligands, the nanoparticle solutions demonstrate exceptional stability due to electric repulsion effect associated with strong negative charging of formed nanoparticles. Stable aqueous solutions of bare gold nanoparticles present a unique object with a variety of potential applications in catalysis, surface-enhanced Raman spectroscopy, photovoltaics, biosensing and biomedicine. (paper)

  3. Production of various sizes and some properties of beryllium pebbles by the rotating electrode method

    Energy Technology Data Exchange (ETDEWEB)

    Iwadachi, T.; Sakamoto, N.; Nishida, K. [NGK Insulators Ltd., Nagoya (Japan); Kawamura, H.

    1998-01-01

    The particle size distribution of beryllium pebbles produced by the rotating electrode method was investigated. Particle size depends on some physical properties and process parameters, which can practicaly be controlled by varying electrode angular velocities. The average particle sizes produced were expressed by the hyperbolic function with electrode angular velocity. Particles within the range of 0.3 and 2.0 mm in diameter are readily produced by the rotating electrode method while those of 0.2 mm in diameter are also fabricable. Sphericity and surface roughness were good in each size of pebble. Grain sizes of the pebbles are 17 {mu} m in 0.25 mm diameter pebbles and 260 {mu} m in 1.8 mm diameter pebbles. (author)

  4. Intriguing structures and magic sizes of heavy noble metal nanoclusters around size 55 governed by relativistic effect and covalent bonding

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, X. J.; Xue, X. L.; Jia, Yu [International Laboratory for Quantum Functional Materials of Henan and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Guo, Z. X. [International Laboratory for Quantum Functional Materials of Henan and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Department of Chemistry and London Centre for Nanotechnology, University College London, London WC1H (United Kingdom); Li, S. F., E-mail: sflizzu@zzu.edu.cn [International Laboratory for Quantum Functional Materials of Henan and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Zhenyu, E-mail: zhangzy@ustc.edu.cn [ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Gao, Y. F., E-mail: ygao7@utk.edu [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-11-07

    Nanoclusters usually display exotic physical and chemical properties due to their intriguing geometric structures in contrast to their bulk counterparts. By means of first-principles calculations within density functional theory, we find that heavy noble metal Pt{sub N} nanoclusters around the size N = 55 begin to prefer an open configuration, rather than previously reported close-packed icosahedron or core-shell structures. Particularly, for Pt{sub N}, the widely supposed icosahedronal magic cluster is changed to a three-atomic-layered structure with D{sub 6h} symmetry, which can be well addressed by our recently established generalized Wulff construction principle (GWCP). However, the magic number of Pt{sub N} clusters around 55 is shifted to a new odd number of 57. The high symmetric three-layered Pt{sub 57} motif is mainly stabilized by the enhanced covalent bonding contributed by both spin-orbital coupling effect and the open d orbital (5d{sup 9}6s{sup 1}) of Pt, which result in a delicate balance between the enhanced Pt–Pt covalent bonding of the interlayers and negligible d dangling bonds on the cluster edges. These findings about Pt{sub N} clusters are also applicable to Ir{sub N} clusters, but qualitatively different from their earlier neighboring element Os and their later neighboring element Au. The magic numbers for Os and Au are even, being 56 and 58, respectively. The findings of the new odd magic number 57 are the important supplementary of the recently established GWCP.

  5. Brain size regulations by cbp haploinsufficiency evaluated by in-vivo MRI based volumetry

    Science.gov (United States)

    Ateca-Cabarga, Juan C.; Cosa, Alejandro; Pallarés, Vicente; López-Atalaya, José P.; Barco, Ángel; Canals, Santiago; Moratal, David

    2015-11-01

    The Rubinstein-Taybi Syndrome (RSTS) is a congenital disease that affects brain development causing severe cognitive deficits. In most cases the disease is associated with dominant mutations in the gene encoding the CREB binding protein (CBP). In this work, we present the first quantitative analysis of brain abnormalities in a mouse model of RSTS using magnetic resonance imaging (MRI) and two novel self-developed automated algorithms for image volumetric analysis. Our results quantitatively confirm key syndromic features observed in RSTS patients, such as reductions in brain size (-16.31%, p < 0.05), white matter volume (-16.00%, p < 0.05), and corpus callosum (-12.40%, p < 0.05). Furthermore, they provide new insight into the developmental origin of the disease. By comparing brain tissues in a region by region basis between cbp+/- and cbp+/+ littermates, we found that cbp haploinsufficiency is specifically associated with significant reductions in prosencephalic tissue, such us in the olfactory bulb and neocortex, whereas regions evolved from the embryonic rhombencephalon were spared. Despite the large volume reductions, the proportion between gray-, white-matter and cerebrospinal fluid were conserved, suggesting a role of CBP in brain size regulation. The commonalities with holoprosencephaly and arhinencephaly conditions suggest the inclusion of RSTS in the family of neuronal migration disorders.

  6. Spray adjuvant effects on droplet size spectra measured by three laser-based systems

    Science.gov (United States)

    Spray droplet size has long been recognized as the most important variable that aerial applicators can influence to mitigate spray drift from the application site. There are several different technologies that are used by researchers to measure droplet size from spray nozzles. The objective of thes...

  7. Nano-sized Y2O3:Eu phosphor particles prepared by spray pyrolysis

    International Nuclear Information System (INIS)

    Y2O3:Eu phosphor particles with nano-sized and non-aggregation characteristics were prepared by spray pyrolysis using spraying solution containing polymeric precursors and Li2CO3 flux material. The post-treated phosphor particles with fine size and high brightness were ball milled to reduce the aggregation degree of the nano-sized Y2O3:Eu phosphor particles. The mean particle size, morphology, and brightness of Y2O3:Eu phosphor particles were strongly affected by contents of the additives and post-treatment temperature. The Y2O3:Eu phosphor particles prepared from the solution containing 0.3 M citric acid, 0.3 M ethylene glycol and 5 wt.% Li2CO3 had fine size and good morphology after post-treatment. The Y2O3:Eu phosphor particles post-treated at 1000 deg. C for 3 h had the mean size of 300 nm. Nano-sized Y2O3:Eu phosphor particles prepared by spray pyrolysis had similar photoluminescence intensity to the micron-sized Y2O3:Eu commercial product prepared by solid state reaction method. The Y2O3:Eu phosphor particles had aggregation-free and regular morphology characteristics even after 30 min ball milling process

  8. Determination of crystallite size and strain by X-ray powder

    International Nuclear Information System (INIS)

    The main methods to determine crystallite size and strain from X-ray powder diffraction data are presented, illustrated by measurements on Co3O4 nanoparticles. Through comparison with the size distribution determined from scanning electron microscopy, the reliability and applicability of these methods are analyzed. (authors)

  9. Self-similar drop-size distributions produced by breakup in chaotic flows

    International Nuclear Information System (INIS)

    Deformation and breakup of immiscible fluids in deterministic chaotic flows is governed by self-similar distributions of stretching histories and stretching rates and produces populations of droplets of widely distributed sizes. Scaling reveals that distributions of drop sizes collapse into two self-similar families; each family exhibits a different shape, presumably due to changes in the breakup mechanism

  10. Preparation and particle size characterization of Cu nanopartides prepared by anodic arc plasma

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Copper nanoparticles were successfully prepared in large scale by means of anodic arc discharging plasma method in inert atmosphere. The particle size, specific surface area, crystal structure, and morphology of the samples were characterized by X-ray diffraction (XRD), BET equation, transmission electron microscopy (TEM), and the corresponding selected area electron diffraction (SAED). The experimental results indicate that the crystal structure of the samples is fcc structure the same as that of the bulk materials. The specific surface area is 11 m2/g, the particle size distribution is 30 to 90nm, and the average particle size is about 67 nm obtained from TEM and confirmed from XRD and BET results. The nanoparticles with uniform size, high purity, narrow size distribution and spherical shape can be prepared by this convenient and effective method.

  11. Solving point reactor kinetic equations by time step-size adaptable numerical methods

    International Nuclear Information System (INIS)

    Based on the analysis of effects of time step-size on numerical solutions, this paper showed the necessity of step-size adaptation. Based on the relationship between error and step-size, two-step adaptation methods for solving initial value problems (IVPs) were introduced. They are Two-Step Method and Embedded Runge-Kutta Method. PRKEs were solved by implicit Euler method with step-sizes optimized by using Two-Step Method. It was observed that the control error has important influence on the step-size and the accuracy of solutions. With suitable control errors, the solutions of PRKEs computed by the above mentioned method are accurate reasonably. The accuracy and usage of MATLAB built-in ODE solvers ode23 and ode45, both of which adopt Runge-Kutta-Fehlberg method, were also studied and discussed. (authors)

  12. Assessing factors causing severe injuries in crashes of high-deck buses in long-distance driving on freeways.

    Science.gov (United States)

    Chu, Hsing-Chung

    2014-01-01

    High-deck buses that have a higher center of gravity traveling at an excessive speed have a higher likelihood of causing serious and fatal accidents when drivers lose control of the vehicle. In addition, drivers who suffer from fatigue in long-distance driving increase the likelihood of serious accident. This paper examines the effects of risk factors contributing to severe crashes associated with high-deck buses used for long-distance driving on freeways. An ordered logit and latent class models are used to examine significant factors on the severity of injuries in crashes related to high-deck buses. Driver fatigue, drivers or passengers not wearing a seat belt, reckless driving, drunk driving, crashes occurred between midnight and dawn, and crashes occurred at interchange ramps were found to significantly affect the severity of injuries in crashes involving high-deck buses. Safety policies to prevent severe injuries in crashes involving high deck buses used for long-distance runs on freeways include: (1) restricting drivers from exceeding the limit of daily driving hours and mandating sufficient rest breaks; (2) installing an automatic sleep-warning device in the vehicle; (3) drivers with obstructive sleep apnea syndrome or sleep disorders should be tested and treated before they are allowed to perform long hours of driving tasks; (4) educating the public or even amending the seatbelt legislation to require all passengers to wear a seat belt and thus reduce the chance of ejection from a high-deck bus and prevent serious injuries in a crash while traveling at a higher speed on freeways. PMID:24144498

  13. Direct and Indirect Evidence of Size-Selective Grazing on Pelagic Bacteria by Freshwater Nanoflagellates

    Science.gov (United States)

    Šimek, Karel; Chrzanowski, Thomas H.

    1992-01-01

    Size-selective grazing of three heterotrophic nanoflagellates (with cell sizes of 21, 44, and 66 μm3) isolated from Lake Arlington, Texas was examined by using a natural mixture of fluorescence labelled lake bacteria. Sizes of ingested bacteria in food vacuoles were directly measured. Larger bacterial cells were ingested at a frequency much higher than that at which they occurred in the assemblage, indicating preferential flagellate grazing on the larger size classes within the lake bacterioplankton. Water samples were collected biweekly from June through September, 1989, fractionated by filtration, and incubated for 40 h at in situ temperatures. The average bacterial size was always larger in water which was passed through 1-μm-pore-size filters (1-μm-filtered water) (which was predator free) than in 5-μm-filtered water (which contained flagellates only) or in unfiltered water (in which all bacterivores were present). The increase of bacterial-cell size in 1-μm-filtered water was caused by a shift in the size structure of the bacterioplankton population. Larger cells became more abundant in the absence of flagellate grazing. PMID:16348811

  14. The neural processing of musical instrument size information in the brain investigated by magnetoencephalography

    Science.gov (United States)

    Rupp, Andre; van Dinther, Ralph; Patterson, Roy D.

    2005-04-01

    The specific cortical representation of size was investigated by recording auditory evoked fields (AEFs) elicited by changes of instrument size and pitch. In Experiment 1, a French horn and one scaled to double the size played a three note melody around F3 or its octave, F4. Many copies of these four melodies were played in random order and the AEF was measured continuously. A similar procedure was applied to saxophone sounds in a separate run. In Experiment 2, the size and type of instrument (French horn and saxophone) were varied without changing the octave. AEFs were recorded in five subjects using magnetoencephalography and evaluated by spatio-temporal source analysis with one equivalent dipole in each hemisphere. The morphology of the source waveforms revealed that each note within the melody elicits a well-defined P1-N1-P2 AEF-complex with adaptation for the 2nd and 3rd note. At the transition of size, pitch, or both, a larger AEF-complex was evoked. However, size changes elicited a stronger N1 than pitch changes. Furthermore, this size-related N1 enhancement was larger for French horn than saxophone. The results indicate that the N1 plays an important role in the specific representation of instrument size.

  15. Brain size regulations by cbp haploinsufficiency evaluated by in-vivo MRI based volumetry

    Science.gov (United States)

    Ateca-Cabarga, Juan C.; Cosa, Alejandro; Pallarés, Vicente; López-Atalaya, José P.; Barco, Ángel; Canals, Santiago; Moratal, David

    2015-11-01

    The Rubinstein-Taybi Syndrome (RSTS) is a congenital disease that affects brain development causing severe cognitive deficits. In most cases the disease is associated with dominant mutations in the gene encoding the CREB binding protein (CBP). In this work, we present the first quantitative analysis of brain abnormalities in a mouse model of RSTS using magnetic resonance imaging (MRI) and two novel self-developed automated algorithms for image volumetric analysis. Our results quantitatively confirm key syndromic features observed in RSTS patients, such as reductions in brain size (-16.31%, p brain tissues in a region by region basis between cbp+/- and cbp+/+ littermates, we found that cbp haploinsufficiency is specifically associated with significant reductions in prosencephalic tissue, such us in the olfactory bulb and neocortex, whereas regions evolved from the embryonic rhombencephalon were spared. Despite the large volume reductions, the proportion between gray-, white-matter and cerebrospinal fluid were conserved, suggesting a role of CBP in brain size regulation. The commonalities with holoprosencephaly and arhinencephaly conditions suggest the inclusion of RSTS in the family of neuronal migration disorders.

  16. Adaptive Constant Modulus Blind Equalization with Variable Step-Size Control by Error Power

    Directory of Open Access Journals (Sweden)

    Ying Xiao

    2012-09-01

    Full Text Available A variable step-size control by error power was proposed to improve the performance of adaptive constant modulus blind equalization algorithm based on the analysis of the cost function. In the Constant Modulus Algorithm (CMA, large step-size can achieve faster convergence rate, but the steady-state residual error is big, on the contrary, small step-size can achieve higher convergence precision, but the convergence rate is slow. A triangle inequality can be set up according to the cost function of CMA and the power of error and signal can be estimated by exponential decay window, then the attenuation function can be obtained to control the step-size change. Meanwhile, the threshold is set to reset the step-size to ensure the tracking performance when the channel has burst interference. Computer simulation results prove the effectiveness of the proposed algorithm.

  17. Determination of size distribution of small DNA fragments by polyacrylamide gel electrophoresis

    International Nuclear Information System (INIS)

    Size distribution determination of DNA fragments can be normally determined by the agarose gel electrophoresis, including the normal DNA banding pattern analysis. However this method is only good for large DNA, such as the DNA of the size of kilo base pairs to mega base pairs range. DNA of size less than kilo base pairs is difficult to be quantified by the agarose gel method. Polyacrylamide gel electrophoresis however can be used to measure the quantity of DNA fragments of size less than kilo base pairs in length, down to less than ten base pairs. This method is good for determining the quantity of the smaller size DNA, single stranded polymers or even some proteins, if the known standards are available. In this report detail description of the method of preparing the polyacrylamide gel, and the experimental set up is discussed. Possible uses of this method, and the comparison with the standard sizes of DNA is also shown. This method is used to determine the distribution of the amount of the fragmented DNA after the Calf-thymus DNA has been exposed to various types of radiation and of different doses. The standards were used to determine the sizes of the fragmented Calf-thymus DNA. The higher the dose the higher is the amount of the smaller size DNA measured

  18. Determination of the particle size distribution of aerosols by means of a diffusion battery

    International Nuclear Information System (INIS)

    The different methods allowing to determine the particle size distribution of aerosols by means of diffusion batteries are described. To that purpose, a new method for the processing of experimental data (percentages of particles trapped by the battery vs flow rate) was developed on the basis of calculation principles which are described and assessed. This method was first tested by numerical simulation from a priori particle size distributions and then verified experimentally using a fine uranine aerosol whose particle size distribution as determined by our method was compared with the distribution previously obtained by electron microscopy. The method can be applied to the determination of particle size distribution spectra of fine aerosols produced by 'radiolysis' of atmospheric gaseous impurities. Two other applications concern the detection threshold of the condensation nuclei counter and the 'critical' radii of 'radiolysis' particles

  19. Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering.

    Science.gov (United States)

    Makan, Ashwell C; Spallek, Markus J; du Toit, Madeleine; Klein, Thorsten; Pasch, Harald

    2016-04-15

    Field flow fractionation (FFF) is an advanced fractionation technique for the analyses of very sensitive particles. In this study, different FFF techniques were used for the fractionation and analysis of polymer emulsions/latexes. As model systems, a pure acrylic emulsion and emulsions containing titanium dioxide were prepared and analyzed. An acrylic emulsion polymerization was conducted, continuously sampled from the reactor and subsequently analyzed to determine the particle size, radius of gyration in specific, of the latex particles throughout the polymerization reaction. Asymmetrical flow field-flow fractionation (AF4) and sedimentation field-flow fractionation (SdFFF), coupled to a multidetector system, multi-angle laser light scattering (MALLS), ultraviolet (UV) and refractive index (RI), respectively, were used to investigate the evolution of particle sizes and particle size distributions (PSDs) as the polymerization progressed. The obtained particle sizes were compared against batch-mode dynamic light scattering (DLS). Results indicated differences between AF4 and DLS results due to DLS taking hydration layers into account, whereas both AF4 and SdFFF were coupled to MALLS detection, hence not taking the hydration layer into account for size determination. SdFFF has additional separation capabilities with a much higher resolution compared to AF4. The calculated radii values were 5nm larger for SdFFF measurements for each analyzed sample against the corresponding AF4 values. Additionally a low particle size shoulder was observed for SdFFF indicating bimodality in the reactor very early during the polymerization reaction. Furthermore, different emulsions were mixed with inorganic species used as additives in cosmetics and coatings such as TiO2. These complex mixtures of species were analyzed to investigate the retention and particle interaction behavior under different AF4 experimental conditions, such as the mobile phase. The AF4 system was coupled online

  20. Improvement of Biohydrogen Production under Increased the Reactor Size by C. acetobutylicum NCIMB 13357

    Directory of Open Access Journals (Sweden)

    Hisham S. Alshiyab

    2009-01-01

    Full Text Available Problem statement: One of the main factors influenced the bacterial productivity and total yield of hydrogen is the partial pressure of produced gas. A novel solution to enhance the bacterial productivity was through reduction of gas pressure. Approach: Increasing the reactor size showed to enhance the bacterial production of hydrogen. Results: The technique of increasing reactor size resulted to enhance the hydrogen yield (YP/S from 269 mL g-1 glucose utilized to maximum yield of 448 mL g-1 glucose utilized by using 125 mL and 2 L reactor size respectively. The hydrogen productivity was also enhanced from 71 mL-1 h-1 to maximum of 91 mL L-1 h-1 was obtained by using 125 mL and 1 L reactor size respectively. Biomass concentration was enhanced from 1.03 g L-1 to maximum of 1.68 g L-1 by using 125 mL and 2 L reactor size were used respectively, hydrogen yield per biomass (YP/X of 267 mL g-1 L-1, biomass per substrate utilized (YX/S of 0.336 and produced hydrogen in gram per gram of glucose utilized (YH2/s of 0.04 when 2 L reactor size was employed. Conclusion: By using bigger reactor size, the effect of gaseous products in fermentation medium was reduced and enhanced both bacterial productivity and biomass concentration.

  1. Characterization of energy barrier and particle size distribution of lyophilized ferrofluids by magnetic relaxation measurements

    International Nuclear Information System (INIS)

    The magnetic properties of a ferrofluid are strongly influenced by its particle size distribution. We analyzed a ferrofluid with an unknown particle size distribution as well as fractionated samples of the original material. The ferrofluid in our investigations consists of a mixture of maghemite and magnetite. We investigated these different samples using temperature-dependent magnetorelaxometry method. The evaluation of the Neel relaxation signal allows us a direct determination of the energy barrier distribution, which is one of the most important parameters of such systems of magnetic nanoparticles. The calculated particle volumes were compared with particle sizes determined by transmission electron microscopy

  2. Characterization of energy barrier and particle size distribution of lyophilized ferrofluids by magnetic relaxation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Schmidl, Frank [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany)]. E-mail: Frank.Schmidl@uni-jena.de; Weber, Peter [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); Koettig, Torsten [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); Buettner, Markus [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); Prass, Stefan [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); Becker, Christoph [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); Mans, Michael [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); Heinrich, Jochen [Innovent Technologieentwicklung, Pruessingstrasse 27B, D-07743 Jena (Germany); Roeder, Michael [Innovent Technologieentwicklung, Pruessingstrasse 27B, D-07743 Jena (Germany); Wagner, Kerstin [Innovent Technologieentwicklung, Pruessingstrasse 27B, D-07743 Jena (Germany); Berkov, Dimitr V. [Innovent Technologieentwicklung, Pruessingstrasse 27B, D-07743 Jena (Germany); Goernert, Peter [Innovent Technologieentwicklung, Pruessingstrasse 27B, D-07743 Jena (Germany); Gloeckl, Gunnar [Institute of Pharmacy, Ernst-Moritz-Arndt-University, D-17487 Greifswald (Germany); Weitschies, Werner [Institute of Pharmacy, Ernst-Moritz-Arndt-University, D-17487 Greifswald (Germany); Seidel, Paul [Institut of Solid State Physics, Friedrich-Schiller-University Jena, D-07743 Jena (Germany)

    2007-04-15

    The magnetic properties of a ferrofluid are strongly influenced by its particle size distribution. We analyzed a ferrofluid with an unknown particle size distribution as well as fractionated samples of the original material. The ferrofluid in our investigations consists of a mixture of maghemite and magnetite. We investigated these different samples using temperature-dependent magnetorelaxometry method. The evaluation of the Neel relaxation signal allows us a direct determination of the energy barrier distribution, which is one of the most important parameters of such systems of magnetic nanoparticles. The calculated particle volumes were compared with particle sizes determined by transmission electron microscopy.

  3. Size and shape controllable preparation of graphene sponge by freezing, lyophilizing and reducing in container

    Institute of Scientific and Technical Information of China (English)

    ZHAO LianQin; YU BaoWei; ZHANG XiaoLiang; WU RuiHan; LIU XiaoYang; LIAO Rong; YANG ShengTao

    2016-01-01

    Graphene sponge (GS) is a porous 3D structure of graphene.Although hydrothermal reduction,chemical vapor deposition,solution reduction and high temperature annealing could be used for the preparation of GS,the size and shape cannot be well controlled.Herein,we reported a facile method to prepare GS under mild condition in a size and shape controllable way.Graphene oxide was lyophilized to form the spongy structure and reduced by steamy hydrazine hydrate to produce GS.The size and shape of GS prepared were nearly identical to that of the container.The reduction degree of GS could be regulated by the reduction temperature and time.

  4. Regulation of aggregate size and pattern by adenosine and caffeine in cellular slime molds

    Directory of Open Access Journals (Sweden)

    Jaiswal Pundrik

    2012-01-01

    Full Text Available Abstract Background Multicellularity in cellular slime molds is achieved by aggregation of several hundreds to thousands of cells. In the model slime mold Dictyostelium discoideum, adenosine is known to increase the aggregate size and its antagonist caffeine reduces the aggregate size. However, it is not clear if the actions of adenosine and caffeine are evolutionarily conserved among other slime molds known to use structurally unrelated chemoattractants. We have examined how the known factors affecting aggregate size are modulated by adenosine and caffeine. Result Adenosine and caffeine induced the formation of large and small aggregates respectively, in evolutionarily distinct slime molds known to use diverse chemoattractants for their aggregation. Due to its genetic tractability, we chose D. discoideum to further investigate the factors affecting aggregate size. The changes in aggregate size are caused by the effect of the compounds on several parameters such as cell number and size, cell-cell adhesion, cAMP signal relay and cell counting mechanisms. While some of the effects of these two compounds are opposite to each other, interestingly, both compounds increase the intracellular glucose level and strengthen cell-cell adhesion. These compounds also inhibit the synthesis of cAMP phosphodiesterase (PdsA, weakening the relay of extracellular cAMP signal. Adenosine as well as caffeine rescue mutants impaired in stream formation (pde4- and pdiA- and colony size (smlA- and ctnA- and restore their parental aggregate size. Conclusion Adenosine increased the cell division timings thereby making large number of cells available for aggregation and also it marginally increased the cell size contributing to large aggregate size. Reduced cell division rates and decreased cell size in the presence of caffeine makes the aggregates smaller than controls. Both the compounds altered the speed of the chemotactic amoebae causing a variation in aggregate size

  5. Formation and characterization of varied size germanium nanocrystals by electron microscopy, Raman spectroscopy, and photoluminescence

    DEFF Research Database (Denmark)

    Ou, Haiyan; Ou, Yiyu; Liu, Chuan;

    2011-01-01

    matrix were formed by complementary metal-oxide-semiconductor compatible technology, e.g. plasma enhanced chemical vapour deposition and annealing. Different sizes of the Ge nanocrystals were prepared and analyzed by transmission electron microscopy with respect to their size, distribution and...... power. It was clarified that two strong emission peaks at 3.19 eV and 4.40 eV are from the interface between Ge nanocrystals and SiO2 matrix....

  6. Size control of monodisperse nonporous silica particles by seed particle growth

    Institute of Scientific and Technical Information of China (English)

    Beibei Zhao; Caihua Tian; Yan Zhang; Tao Tang; Fengyun Wang

    2011-01-01

    Monodisperse nonporous silica particles were prepared by sol-precipitation via seed particle growth method, and the particle size, which varied from 1.0 to 4.7 μm, was strictly controlled in our experiment.The formation of secondary particles, which resulted in a multimodal distribution of particle size, was suppressed by changing tetraethoxysilane (TEOS) concentration and reaction temperature. Furthermore,the effect of adding small amounts of electrolyte to the hydrolysis mixture was examined.

  7. Nano-sized ceria particles prepared by spray pyrolysis using polymeric precursor solution

    International Nuclear Information System (INIS)

    Nano-sized ceria particles were prepared from the aqueous solution containing the polymeric precursors by ultrasonic spray pyrolysis at the severe preparation conditions such as high flow rate of carrier gas and short residence time. The key idea to produce nanoparticles was to prepare hollow ceria particles which are easily turned to aggregates of nano-sized primary particles during the post-thermal treatment and thereafter disintegrate such aggregates to nano-sized particles by a simple ball milling process. It was found that using the polymeric precursor strongly influences the crystallization characteristics and morphological changes of the as-prepared particles during the post-thermal treatment. The as-prepared particles prepared from the polymeric precursor solution had non-spherical shape and fractured structure with a thin shell, whereas the as-prepared and calcined ceria particles obtained from the aqueous solution had spherical shape and hollow morphology with a thick shell. Also, nano-sized ceria particles prepared from the polymeric precursor solution had less aggregated structure than those prepared from the aqueous solution. For the ceria particles prepared from the polymeric precursor solution, the degree of aggregation between the primary particles was reduced as increasing the calcination temperature. As a result, aggregation-free nano-sized ceria particles were obtained above 1200 deg. C without a milling process. The mean size of the primary particles increased from several tens nanometer to submicrometer size as the calcination temperature changed from 800 to 1300 deg. C

  8. The Nano-Sized In2O3 Powder Synthesis by Sol-Gel Method

    Institute of Scientific and Technical Information of China (English)

    潘庆谊; 程知萱; 等

    2002-01-01

    Wiwh InCl3·4H2O being used as raw materials,the precursor of nano-sized In2O3 powder was prepared by hydrolysis,peptization and gelation of InCl3·4H2O.After calcination,nano-sized In2O3 powder was obtained.The powder was characterized by thermogravimetric and differential thermal analysis(TG-DTA).X-ray diffractometry(XRD)and transmission electron microscopy(TEM),respectively,Calculation revealed that the mean crystablline size increased with increasing the calcination temperature,but crystal lattice distortion rate decreased with the increasing in the average crystalline size.This indicated that the smaller the particle size,the bigger the crystal lattice distortion,the worse the crystal growing.The activation energies for growth of nano-sized In2O3 were calculated to be 4.75kJ·mol-1 at the calcination temperature up tp 500℃ and 66.40kJ· mol-1 at the calcination temperature over 600℃.TEM photos revealed that the addition of the chemical additive(OP-10)greatly influenced the morphology and size of In2O3 particles.

  9. Size dependence of yield strength simulated by a dislocation-density function dynamics approach

    Science.gov (United States)

    Leung, P. S. S.; Leung, H. S.; Cheng, B.; Ngan, A. H. W.

    2015-04-01

    The size dependence of the strength of nano- and micron-sized crystals is studied using a new simulation approach in which the dynamics of the density functions of dislocations are modeled. Since any quantity of dislocations can be represented by a density, this approach can handle large systems containing large quantities of dislocations, which may handicap discrete dislocation dynamics schemes due to the excessive computation time involved. For this reason, pillar sizes spanning a large range, from the sub-micron to micron regimes, can be simulated. The simulation results reveal the power-law relationship between strength and specimen size up to a certain size, beyond which the strength varies much more slowly with size. For specimens smaller than ∼4000b, their strength is found to be controlled by the dislocation depletion condition, in which the total dislocation density remains almost constant throughout the loading process. In specimens larger than ∼4000b, the initial dislocation distribution is of critical importance since the presence of dislocation entanglements is found to obstruct deformation in the neighboring regions within a distance of ∼2000b. This length scale suggests that the effects of dense dislocation clusters are greater in intermediate-sized specimens (e.g. 4000b and 8000b) than in larger specimens (e.g. 16 000b), according to the weakest-link concept.

  10. Particle sizing in dense two-phase droplet systems by ultrasonic attenuation and velocity spectra

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Size and size distribution of particles in particulate two-phase flow play an important role in a wide variety of industrial areas,while their measurement still remains a hard task till now.Ultrasonic wave as a mechanical vibration contains plenty of information about medium when it passes through.Thus the size distribution could be extracted from the measured ultrasonic attenuation and velocity spectra by means of well established models and data processing techniques.This paper contributes to the extraction of information of droplet size of a two-phase fat emulsion simultaneously from signals of broad-band ultrasonic attenuation and velocity spectra.According to the formulated single particle scattering model,the relationship between particle size distribution and ultrasonic spectrum is estab-lished.The sensitivities of ultrasonic spectra to the variation of particle size are illustrated.Distin-guishing features for attenuation and velocity spectra are summarized.Demonstration calculations of inversion by optimum regularization factor method are carried out to yield the typical numerical results for discussion.Based on the proposed inversion algorithm and theoretical model,a fat emulsion sam-ple with a volume fraction up to 20% is measured and analyzed.To validate the proposed ultrasonic spectrum particle sizing method,the results are compared to those obtained from optical measure-ment.

  11. Particle sizing in dense two-phase droplet systems by ultrasonic attenuation and velocity spectra

    Institute of Scientific and Technical Information of China (English)

    SU MingXu; CAI XiaoShu; XUE MingHua; DONG LiLi; XU Feng

    2009-01-01

    Size and size distribution of particles in particulate two-phase flow play an important role in a wide va-riety of industrial areas, while their measurement still remains a hard task till now. Ultrasonic wave as a mechanical vibration contains plenty of information about medium when it passes through. Thus the size distribution could be extracted from the measured ultrasonic attenuation and velocity spectra by means of well established models and data processing techniques. This paper contributes to the ex-traction of information of droplet size of a two-phase fat emulsion simultaneously from signals of broad-band ultrasonic attenuation and velocity spectra. According to the formulated single particle scattering model, the relationship between particle size distribution and ultrasonic spectrum is estab-lished. The sensitivilles of ultrasonic spectra to the variation of particle size are illustrated. Distin-guishing features for attenuation and velocity spectra are summarized. Demonstration calculations of inversion by optimum regularization factor method are carried out to yield the typical numerical results for discussion. Based on the proposed inversion algorithm and theoretical model, a fat emulsion sam-ple with a volume fraction up to 20% is measured and analyzed. To validate the proposed ultrasonic spectrum particle sizing method, the results are compared to those obtained from optical measure-ment.

  12. Effect of particle size on microstructure and mechanical properties of composites produced by ARB process

    International Nuclear Information System (INIS)

    Research highlights: → Microstructure of MMC with larger particles becomes completely uniform, sooner. → When the number of cycles increased, tensile strength for both samples improved. → Up to the seventh cycle, tensile strength of MMC with larger particles was bigger. → First, the tensile elongation of MMCs was decreased, and then it was improved. - Abstract: In the present work, Al/10 vol.% SiC metal matrix composite (MMC) was manufactured by accumulative roll bonding (ARB) process. The silicon carbide particles with two various particle sizes of 40 and 2 μm were used. Effect of particle size on microstructure (by scanning electron microscopy) and mechanical properties (tensile strength and elongation) at various ARB cycles was investigated. It was found that the microstructural evolution in MMC with 40 μm particle size was more salient compared to the MMCs with 2 μm particle size. Also, the composite strip with 40 μm particle size became uniform with high bonding quality and without any porosity sooner than the strip of 2 μm particle size. Moreover, when the number of cycles was increased, the tensile strength for both samples was improved. The tensile strength of the composite strip with 40 μm particle size was more than the composite strip with 2 μm up to the seventh cycle. By increasing the number of cycles after the seventh cycle, the value of tensile strength of MMC with 40 μm particle size became saturated and then decreased, and its tensile strength became less than that of the composite with 2 μm particle size for the ninth and eleventh cycles. Up to the seventh cycle, when the number of ARB cycles was increased, the elongation of composite strips was decreased, but after the ninth cycle, the tensile elongation for both samples was improved.

  13. Effect of particle size on microstructure and mechanical properties of composites produced by ARB process

    Energy Technology Data Exchange (ETDEWEB)

    Jamaati, Roohollah, E-mail: r.jamaatikenari@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Amirkhanlou, Sajjad; Toroghinejad, Mohammad Reza; Niroumand, Behzad [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-02-25

    Research highlights: {yields} Microstructure of MMC with larger particles becomes completely uniform, sooner. {yields} When the number of cycles increased, tensile strength for both samples improved. {yields} Up to the seventh cycle, tensile strength of MMC with larger particles was bigger. {yields} First, the tensile elongation of MMCs was decreased, and then it was improved. - Abstract: In the present work, Al/10 vol.% SiC metal matrix composite (MMC) was manufactured by accumulative roll bonding (ARB) process. The silicon carbide particles with two various particle sizes of 40 and 2 {mu}m were used. Effect of particle size on microstructure (by scanning electron microscopy) and mechanical properties (tensile strength and elongation) at various ARB cycles was investigated. It was found that the microstructural evolution in MMC with 40 {mu}m particle size was more salient compared to the MMCs with 2 {mu}m particle size. Also, the composite strip with 40 {mu}m particle size became uniform with high bonding quality and without any porosity sooner than the strip of 2 {mu}m particle size. Moreover, when the number of cycles was increased, the tensile strength for both samples was improved. The tensile strength of the composite strip with 40 {mu}m particle size was more than the composite strip with 2 {mu}m up to the seventh cycle. By increasing the number of cycles after the seventh cycle, the value of tensile strength of MMC with 40 {mu}m particle size became saturated and then decreased, and its tensile strength became less than that of the composite with 2 {mu}m particle size for the ninth and eleventh cycles. Up to the seventh cycle, when the number of ARB cycles was increased, the elongation of composite strips was decreased, but after the ninth cycle, the tensile elongation for both samples was improved.

  14. Vertical Beam Size Measurement by Streak Camera under Colliding and Single Beam Conditions in KEKB

    CERN Document Server

    Ikeda, Hitomi; Fukuma, Hitoshi; Funakoshi, Yoshihiro; Hiramatsu, Shigenori; Mitsuhashi, Toshiyuki; Ohmi, Kazuhito; Uehara, Sadaharu

    2005-01-01

    Beam behavior of KEKB was studied by measurement of the beam size using a streak camera. Effect of the electron-cloud and the parasitic collision on the vertical beam size was examined in beam collision. We intentionally injected a test bunch of positrons after 2 rf buckets of a bunch to enhance the electron cloud effect and changed electron beam conditions to see the beam-beam effect. The beam size was also measured with a single positron beam and compared with that during collision. The result of the measurement is reported in this paper.

  15. Size-selective separation of DNA fragments by using lysine-functionalized silica particles

    Science.gov (United States)

    Liu, Lingling; Guo, Zilong; Huang, Zhenzhen; Zhuang, Jiaqi; Yang, Wensheng

    2016-02-01

    In this work, a facile and efficient approach has been demonstrated for size-selective separation of DNA fragments by using lysine-functionalized silica particles. At a given pH, the environmental ionic strength can be utilized to alter the electrostatic interactions of lysine-functionalized silica particles with DNA fragments and in turn the DNA fragments on the silica particle surfaces, which exhibits a clear dependence on the DNA fragment sizes. By carefully adjusting the environmental pH and salt concentration, therefore, the use of the lysine-functionalized silica particles allows effective separation of binary and ternary DNA mixtures, for example, two different DNA fragments with sizes of 101 and 1073 bp, 101 and 745 bp, 101 and 408 bp, respectively, and three different DNA fragments with sizes of 101, 408 and 1073 bp.

  16. Preparation of uniform-sized agarose beads by microporous membrane emulsification technique.

    Science.gov (United States)

    Zhou, Qing-Zhu; Wang, Lian-Yan; Ma, Guang-Hui; Su, Zhi-Guo

    2007-07-01

    Uniform-sized agarose beads were prepared by membrane emulsification technique in this study. Agarose was dissolved in boiling water (containing 0.9% sodium chloride) and used as water phase. A mixture of liquid paraffin and petroleum ether containing 4 wt% of hexaglycerin penta ester (PO-500) emulsifier was used as oil phase. At 55 degrees C, the water phase permeated through uniform pores of microporous membrane into the oil phase by a pressure of nitrogen gas to form uniform W/O emulsion. Then the emulsion was cooled down to room temperature under gentle agitation to form gel beads. The effect of oil phase, emulsifier, especially temperature on the uniformity of the beads were investigated and interpreted from interfacial tension between water phase and oil phase. Under optimized condition, the coefficient variation (C.V.) showing the size distribution of the beads was under 15%. This was the first report to prepare uniform agarose beads by membrane emulsification, and to investigate the effect of temperature on the size distribution of the droplets and beads. The beads with different size can be prepared by using membranes with different pore size, and the result showed that there was a linear relationship between the average diameter of beads and pore size of the membranes; beads with diameter from 15 to 60 microm were able to obtain in this study. PMID:17362974

  17. SCFSAP controls organ size by targeting PPD proteins for degradation in Arabidopsis thaliana

    Science.gov (United States)

    Wang, Zhibiao; Li, Na; Jiang, Shan; Gonzalez, Nathalie; Huang, Xiahe; Wang, Yingchun; Inzé, Dirk; Li, Yunhai

    2016-01-01

    Control of organ size by cell proliferation and growth is a fundamental process, but the mechanisms that determine the final size of organs are largely elusive in plants. We have previously revealed that the ubiquitin receptor DA1 regulates organ size by repressing cell proliferation in Arabidopsis. Here we report that a mutant allele of STERILE APETALA (SAP) suppresses the da1-1 mutant phenotype. We show that SAP is an F-box protein that forms part of a SKP1/Cullin/F-box E3 ubiquitin ligase complex and controls organ size by promoting the proliferation of meristemoid cells. Genetic analyses suggest that SAP may act in the same pathway with PEAPOD1 and PEAPOD2, which are negative regulators of meristemoid proliferation, to control organ size, but does so independently of DA1. Further results reveal that SAP physically associates with PEAPOD1 and PEAPOD2, and targets them for degradation. These findings define a molecular mechanism by which SAP and PEAPOD control organ size. PMID:27048938

  18. Aero particles characterization emitted by mobile sources

    International Nuclear Information System (INIS)

    In our country, the mobile sources that conform most of the emissions at the atmosphere, are concentrated on the urban areas. For the present work, samples coming from the escapes of terrestrial transport were obtained, such as: passenger buses, load transport and particular vehicles of the Metropolitan area of the Toluca valley. The material was analyzed by means of scanning electron microscopy of low vacuum and X-ray diffraction. The objective was to characterize the emitted particles by mobile sources, morphological and chemically to know the structure, size and elements that compose them. (Author)

  19. Single particle optical sizing; aggregation of polystyrene latices by salt and polymer.

    OpenAIRE

    Pelssers, E.G.M.

    1988-01-01

    The subject of this thesis is the development of a Single Particle Optical Sizer (SPOS) which is capable of measuring in detail discrete particle size distributions in the colloidal size range. With this instrument we studied the aggregation of latices induced by polymer and salt, and found evidence for non-equilibrium flocculation.Chapter 2 is an inventory of the existing methods of measuring aggregation. A comparison is made with our SPOS instrument. The techniques are classified into three...

  20. Plasmonic nanoparticle films for solar cell applications fabricated by size-selective aerosol deposition

    OpenAIRE

    Pfeiffer, T.V.; Ortiz Gonzalez, J.; Santbergen, R.; Tan, H.; Schmidt-Ott, A.; Zeman, M.; Smets, A.H.M.

    2014-01-01

    A soft deposition method for incorporating surface plasmon resonant metal nanoparticles within photovoltaic devices was studied. This self-assembly method provides excellent control over both nanoparticle size and surface coverage. Films of spherical Ag nanoparticles with diameter of ∼100 nm were fabricated by depositing size-selected aerosols on various substrates using electrophoresis. This novel deposition method opens the route to embed plasmonic nanoparticles in the intermediate reflecto...

  1. Regulation of aggregate size and pattern by adenosine and caffeine in cellular slime molds

    OpenAIRE

    Jaiswal Pundrik; Soldati Thierry; Thewes Sascha; Baskar Ramamurthy

    2012-01-01

    Abstract Background Multicellularity in cellular slime molds is achieved by aggregation of several hundreds to thousands of cells. In the model slime mold Dictyostelium discoideum, adenosine is known to increase the aggregate size and its antagonist caffeine reduces the aggregate size. However, it is not clear if the actions of adenosine and caffeine are evolutionarily conserved among other slime molds known to use structurally unrelated chemoattractants. We have examined how the known factor...

  2. Evaluation of crystallite size distribution by a capillary spinner-scan method in synchrotron powder diffractometry

    International Nuclear Information System (INIS)

    A method to evaluate the effects of particle statistics in capillary-specimen transmission mode x-ray diffraction measurements has been developed. Average crystallite size of about several μm and dispersion of crystallite size distribution have been evaluated by statistical analysis of spinner-scan diffraction intensity data. The method can be applied to polycrystalline materials and also multi-phase mixtures.

  3. Influence of Size Effects on Uptake of Impurity Atoms by Aerosol Nanoparticles Growing in Vapor Condensation

    OpenAIRE

    Levdansky, V.V.

    2014-01-01

    It is known that impurity atoms (molecules) in the main substance can affect its physicochemical properties. Semiconductor doping is paramount in micro- and nanoelectronics. In some cases nanoparticle doping is needed. Nanoparticle doping in the general case depends on the size of nanoparticles. Below we consider theoretically size effects in the uptake of impurity (dopant) atoms by the aerosol nanoparticle that grows in the supersaturated vapor.

  4. A PSO-DP Based Method to Determination of the Optimal Number, Location, and Size of FACTS Devices in Power Systems

    Directory of Open Access Journals (Sweden)

    SHOJAEIAN, S.

    2014-02-01

    Full Text Available The presence of reactive component of current in transmission lines causes adverse impact on the network, including power losses, reduction of line capacity, and voltage drop. These adverse impacts can be reduced by using the first or second generation of FACTS devices. In this paper, these adverse impacts can be reduced optimally by using one of the modern optimization techniques, i.e., particle swarm optimization algorithm (PSO algorithm. By using this algorithm, the optimal size of the static VAr compensator (FACTS devices in a 30 bus IEEE test system is determined. At first, the load flow equations of the 30 bus IEEE test system is defined in the MATLAB software by means of dynamic programming method, and the number of SVCs will be determined by using the system sensitivity function (power losses and the sum of buses voltage drop square; then, the optimal sizes of the FACTS devices is obtained by means of PSO algorithm.

  5. Metal uptake by corn grown on media treated with particle-size fractionated biosolids

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Weiping [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States)], E-mail: chenweip@yahoo.com.cn; Chang, Andrew C.; Wu, Laosheng [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States); Zhang, Yongsong [School of Environmental and Natural Resources Sciences, Zhejiang University, Hangzhou, Zhejiang, 31009 (China)

    2008-03-15

    Particle-size of biosolids may affect plant uptake of heavy metals when the biosolids are land applied. In this study, corn (Zea mays L.) was grown on sand media treated with biosolids to study how particle-size of biosolids affected the plant uptake of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Two biosolids, the Nu-Earth biosolids and the Los Angeles biosolids, of dissimilar surface morphology were utilized. The former exhibited a porous and spongy structure and had considerably greater specific surface area than that of the latter, which was granular and blocky. The specific surface area of the Los Angeles biosolids was inversely proportional to its particle-size, while that of Nu-Earth biosolids did not change significantly with particle-size. For each biosolid, the metal concentrations were not affected by particle sizes. The biomass yields of plants grown on the treated media increased as the biosolid particle-size decreased, indicating that plant uptake of nutrients from biosolids was dependent on interactions at the root-biosolids interface. The effect of particle-size on a metal's availability to plants was element-specific. The uptake rate of Cd, Zn, Cu, and Ni was correlated with the surface area of the particles, i.e., smaller particles having higher specific area provided greater root-biosolids contact and resulted in enhanced uptake of Cd and Zn and slightly less increased uptake of Cu and Ni. The particle morphology of biosolids had limited influence on the plant tissue concentrations of Cr and Pb. For both types of biosolids, total metal uptake increased as biosolid particle-size decreased. Our research indicates that biosolid particle-size distribution plays a deciding role in plant uptake of heavy metals when they are land applied.

  6. Habitat selection by breeding waterbirds at ponds with size-structured fish populations

    Science.gov (United States)

    Kloskowski, Janusz; Nieoczym, Marek; Polak, Marcin; Pitucha, Piotr

    2010-07-01

    Fish may significantly affect habitat use by birds, either as their prey or as competitors. Fish communities are often distinctly size-structured, but the consequences for waterbird assemblages remain poorly understood. We examined the effects of size structure of common carp ( Cyprinus carpio) cohorts together with other biotic and abiotic pond characteristics on the distribution of breeding waterbirds in a seminatural system of monocultured ponds, where three fish age classes were separately stocked. Fish age corresponded to a distinct fish size gradient. Fish age and total biomass, macroinvertebrate and amphibian abundance, and emergent vegetation best explained the differences in bird density between ponds. Abundance of animal prey other than fish (aquatic macroinvertebrates and larval amphibians) decreased with increasing carp age in the ponds. Densities of ducks and smaller grebes were strongly negatively associated with fish age/size gradient. The largest of the grebes, the piscivorous great crested grebe ( Podiceps cristatus), was the only species that preferred ponds with medium-sized fish and was positively associated with total fish biomass. Habitat selection by bitterns and most rallids was instead strongly influenced by the relative amount of emergent vegetation cover in the ponds. Our results show that fish size structure may be an important cue for breeding habitat choice and a factor affording an opportunity for niche diversification in avian communities.

  7. Synthesis and characterization of nano-sized MgB2 powder by spray pyrolysis method

    International Nuclear Information System (INIS)

    The nano-sized MgB2 powder was prepared by spray pyrolysis method in order to improve its flux pinning properties by increasing the number of grain boundaries. MgB2 powder was synthesized using spray pyrolysis technique followed by a post-annealing process without excessive magnesium addition. The feed solution was prepared by dissolving the correct amounts of Boric acid and Magnesium acetate tetrahydrate into distillated water and ethanol solution and the overall concentration were fixed at 0.1 mol/L. During the decomposition, 96% Ar-4% H2 was used as carrier gas. The collected powders were characterized by X-ray diffraction, scanning electron microscopy, particle size analyzer, and physical property measurement system. The particles prepared by spray pyrolysis showed spherical morphology and uniform distribution with the average size of 1 μm. The onset of superconducting Tc for synthesized MgB2 powder was around 38 K

  8. Fast Charging Battery Buses for the Electrification of Urban Public Transport : A Feasibility Study Focusing on Charging Infrastructure and Energy Storage Requirements

    OpenAIRE

    Matthias Rogge; Sebastian Wollny; Dirk Uwe Sauer

    2015-01-01

    The electrification of public transport bus networks can be carried out utilizing different technological solutions, like trolley, battery or fuel cell buses. The purpose of this paper is to analyze how and to what extent existing bus networks can be electrified with fast charging battery buses. The so called opportunity chargers use mainly the regular dwell time at the stops to charge their batteries. This results in a strong linkage between the vehicle scheduling and the infrastructure plan...

  9. Reduction of effective terahertz focal spot size by means of nested concentric parabolic reflectors

    Directory of Open Access Journals (Sweden)

    V. A. Neumann

    2015-09-01

    Full Text Available An ongoing limitation of terahertz spectroscopy is that the technique is generally limited to the study of relatively large samples of order 4 mm across due to the generally large size of the focal beam spot. We present a nested concentric parabolic reflector design which can reduce the terahertz focal spot size. This parabolic reflector design takes advantage of the feature that reflected rays experience a relative time delay which is the same for all paths. The increase in effective optical path for reflected light is equivalent to the aperture diameter itself. We have shown that the light throughput of an aperture of 2 mm can be increased by a factor 15 as compared to a regular aperture of the same size at low frequencies. This technique can potentially be used to reduce the focal spot size in terahertz spectroscopy and enable the study of smaller samples.

  10. Reduction of effective terahertz focal spot size by means of nested concentric parabolic reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, V. A., E-mail: v.a.neumann@student.utwente.nl [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland, 21218 (United States); Faculty of Science & Technology, University of Twente, 7500 AE Enschede (Netherlands); Laurita, N. J.; Pan, LiDong; Armitage, N. P., E-mail: npa@pha.jhu.edu [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland, 21218 (United States)

    2015-09-15

    An ongoing limitation of terahertz spectroscopy is that the technique is generally limited to the study of relatively large samples of order 4 mm across due to the generally large size of the focal beam spot. We present a nested concentric parabolic reflector design which can reduce the terahertz focal spot size. This parabolic reflector design takes advantage of the feature that reflected rays experience a relative time delay which is the same for all paths. The increase in effective optical path for reflected light is equivalent to the aperture diameter itself. We have shown that the light throughput of an aperture of 2 mm can be increased by a factor 15 as compared to a regular aperture of the same size at low frequencies. This technique can potentially be used to reduce the focal spot size in terahertz spectroscopy and enable the study of smaller samples.

  11. Reduction of effective terahertz focal spot size by means of nested concentric parabolic reflectors

    International Nuclear Information System (INIS)

    An ongoing limitation of terahertz spectroscopy is that the technique is generally limited to the study of relatively large samples of order 4 mm across due to the generally large size of the focal beam spot. We present a nested concentric parabolic reflector design which can reduce the terahertz focal spot size. This parabolic reflector design takes advantage of the feature that reflected rays experience a relative time delay which is the same for all paths. The increase in effective optical path for reflected light is equivalent to the aperture diameter itself. We have shown that the light throughput of an aperture of 2 mm can be increased by a factor 15 as compared to a regular aperture of the same size at low frequencies. This technique can potentially be used to reduce the focal spot size in terahertz spectroscopy and enable the study of smaller samples

  12. Modeling size controlled nanoparticle precipitation with the co-solvency method by spinodal decomposition.

    Science.gov (United States)

    Keßler, Simon; Schmid, Friederike; Drese, Klaus

    2016-09-14

    The co-solvency method is a method for the size controlled preparation of nanoparticles like polymersomes, where a poor co-solvent is mixed into a homogeneous copolymer solution to trigger precipitation of the polymer. The size of the resulting particles is determined by the rate of co-solvent addition. We use the Cahn-Hilliard equation with a Flory-Huggins free energy model to describe the precipitation of a polymer under changing solvent quality by applying a time dependent Flory-Huggins interaction parameter. The analysis focuses on the characteristic size R of polymer aggregates that form during the initial spinodal decomposition stage, and especially on how R depends on the rate s of solvent quality change. Both numerical results and a perturbation analysis predict a power law dependence R∼s(-⅙), which is in agreement with power laws for the final particle sizes that have been reported from experiments and molecular dynamics simulations. Hence, our model results suggest that the nanoparticle size in size-controlled precipitation is essentially determined during the spinodal decomposition stage. PMID:27502026

  13. Narrowly size-distributed cobalt salt containing poly(2-hydroxyethyl methacrylate) particles by inverse miniemulsion.

    Science.gov (United States)

    Cao, Zhihai; Wang, Zhuo; Herrmann, Christine; Ziener, Ulrich; Landfester, Katharina

    2010-05-18

    Cobalt-containing hybrid particles have been prepared through the encapsulation of cobalt tetrafluoroborate hexahydrate (CoTFB) via inverse miniemulsion polymerization of 2-hydroxyethyl methacrylate (HEMA). We systematically varied the amount and type of cosolvent (water, methanol, ethanol, ethylene glycol), apolar continuous phase (cyclohexane, isooctane, isopar M, hexadecane), amount of cobalt salt, and molecular weight of the polymeric surfactant. The influence of those parameters on the particle size, size distribution, and particle morphology were investigated. Narrowly size-distributed hybrid particles with good colloidal stability could be obtained in a wide range of cobalt content between 5.7 and 22.6 wt % salt relative to the monomer. The addition of a cosolvent such as water not only promotes the loading of metal salt but also has a positive influence on narrowing the particle size distribution. We assume that generally narrowly size-distributed particles can be obtained for a large variety of combinations of polar/apolar phase by adjusting the balance between osmotic and Laplace pressure via the solubility of the metal salt in the continuous phase and lowering the interfacial tension by adjusting the hydrophilic-lipophilic balance (HLB) value of the surfactant. The results show a significant advantage of the inverse miniemulsion over the direct system with respect to the variability and total amount of metal salt without losing the narrow particle size distribution and colloidal stability. PMID:20112941

  14. Body ownership affects visual perception of object size by rescaling the visual representation of external space.

    Science.gov (United States)

    van der Hoort, Björn; Ehrsson, H Henrik

    2014-07-01

    Size perception is most often explained by a combination of cues derived from the visual system. However, this traditional cue approach neglects the role of the observer's body beyond mere visual comparison. In a previous study, we used a full-body illusion to show that objects appear larger and farther away when participants experience a small artificial body as their own and that objects appear smaller and closer when they assume ownership of a large artificial body ("Barbie-doll illusion"; van der Hoort, Guterstam, & Ehrsson, PLoS ONE, 6(5), e20195, 2011). The first aim of the present study was to test the hypothesis that this own-body-size effect is distinct from the role of the seen body as a direct familiar-size cue. To this end, we developed a novel setup that allowed for occlusion of the artificial body during the presentation of test objects. Our results demonstrate that the feeling of ownership of an artificial body can alter the perceived sizes of objects without the need for a visible body. Second, we demonstrate that fixation shifts do not contribute to the own-body-size effect. Third, we show that the effect exists in both peri-personal space and distant extra-personal space. Finally, through a meta-analysis, we demonstrate that the own-body-size effect is independent of and adds to the classical visual familiar-size cue effect. Our results suggest that, by changing body size, the entire spatial layout rescales and new objects are now perceived according to this rescaling, without the need to see the body. PMID:24806404

  15. Estimation by radiation inactivation of the size of functional units governing Sendai and influenza virus fusion

    International Nuclear Information System (INIS)

    The target sizes associated with fusion and hemolysis carried out by Sendai virus envelope glycoproteins were determined by radiation inactivation analysis. The target size for influenza virus mediated fusion with erythrocyte ghosts at pH 5.0 was also determined for comparison. Sendai-mediated fusion with erythrocyte ghosts at pH 7.0 was likewise inactivated exponentially with increasing radiation dose, yielding a target size of 60 +/- 6 kDa, a value consistent with the molecular weight of a single F-protein molecule. The inactivation curve for Sendai-mediated fusion with cardiolipin liposomes at pH 7.0, however, was more complex. Assuming a multiple target-single hit model, the target consisted of 2-3 units of ca. 60 kDa each. A similar target was seen if the liposome contained 10% gangliosides or if the reaction was measured at pH 5.0, suggesting that fusion occurred by the same mechanism at high and low pH. A target size of 261 +/- 48 kDa was found for Sendai-induced hemolysis, in contrast with influenza, which had a more complex target size for this activity. Sendai virus fusion thus occurs by different mechanisms depending upon the nature of the target membrane, since it is mediated by different functional units. Hemolysis is mediated by a functional unit different from that associated with erythrocyte ghost fusion or with cardiolipin liposome fusion

  16. Size-controllable fabrication of Cu nanoparticles on carbon nanotubes by simple heating

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chun; Wu, Shujing; Zheng, He; Cao, Fan; Sheng, Huaping; Zhao, Dongshan; Wang, Jianbo

    2015-01-15

    Highlights: • Cu nanoparticles were synthesized on the surface of carbon nanotubes by heating. • The particle size could be tuned by controlling the temperature and duration. • The possible nucleation and growth mechanisms of nanoparticles were discussed. - Abstract: In this paper, employing simple heating inside the transmission electron microscope, we demonstrated the decoration of carbon nanotubes (CNTs) by Cu nanoparticles (NPs). More significantly, the particle sizes could be effectively controlled by simply controlling the temperature and duration. It is believed that the nucleation and growth of NPs results from the deposition of generated Cu vapor as well as the surface diffusion of Cu on the CNTs at elevated temperature.

  17. Size-controllable fabrication of Cu nanoparticles on carbon nanotubes by simple heating

    International Nuclear Information System (INIS)

    Highlights: • Cu nanoparticles were synthesized on the surface of carbon nanotubes by heating. • The particle size could be tuned by controlling the temperature and duration. • The possible nucleation and growth mechanisms of nanoparticles were discussed. - Abstract: In this paper, employing simple heating inside the transmission electron microscope, we demonstrated the decoration of carbon nanotubes (CNTs) by Cu nanoparticles (NPs). More significantly, the particle sizes could be effectively controlled by simply controlling the temperature and duration. It is believed that the nucleation and growth of NPs results from the deposition of generated Cu vapor as well as the surface diffusion of Cu on the CNTs at elevated temperature

  18. Urban transportation system optimum: The effect of accounting for the interaction of buses and cars

    Directory of Open Access Journals (Sweden)

    Cristian Angelo Guevara

    2011-01-01

    Full Text Available En este trabajo se usa un método iterativo para calcular tarifas Pigouvianascuando las vías son compartidas por autos y buses. Se comparan escenarios en los cuales: 1 la tarifa es calculada considerando sólo la externalidad sobre otros vehículos; 2 la tarifa considera además la externalidad sobre los pasajeros de los vehículos; 3 no se aplican tarifas; y 4 no se aplican tarifas, pero algunas pistas son reservadas para el uso exclusivo de buses. El método es aplicado primero a un modelo idealizado que considera homogenidad de la demanda y cierto grado de heterogenidad en la oferta. Luego el método es aplicado en un experimento con datos reales basado en un modelo simultáneo de cuatro etapas calibrado para la ciudad de Santiago, Chile. Todos los experimentos muestran que cuando se considera la externalidad sobre los pasajeros de los vehículos, las tarifas Pigouvianas crecen sustancialmente en las vías de uso mixto, lo cual se traduce en un menor flujo de automóviles en dichas vías. Por otro lado, las simulaciones con el modelo idealizado muestran que el efecto de la reservación de pistas depende fuertemente del diseño considerado. Respecto de la tarificación Pigouviana, el experimento con datos reales muestra, sorprendentemente, que dicha política resultaría ser inferior a un escenario en el cual no se aplican tarifas. Este resultado podría atribuirse a: 1 que el modelo con datos reales representa una situación de equilibrio general y en cambio las tarifas Pigouvianas se calculan usando un enfoque de equilibrio parcial; 2 limitaciones de modelación en el experimento con datos reales; o 3 una manifestación del contraejemplo de Coase para los impuestos Pigouvianos. El artículo termina discutiendo el impacto de estos resultados en el análisis de políticas de transporte urbano.

  19. From Forced Busing to Free Choice in Public Schools: Quasi-Experimental Evidence of Individual and General Effects

    OpenAIRE

    Victor Lavy

    2006-01-01

    In 1994 the city of Tel Aviv replaced its existing school integration program based on inter-district busing, with a new program that allowed students to choose freely between schools in and out of district. This paper explores the impact of this program on high school outcomes while distinguishing the effect of choice on individual students from general equilibrium effects on affected districts. The identification is based on a regression discontinuity design that yields comparison groups dr...

  20. Measurement of eye size illusion caused by eyeliner, mascara, and eye shadow.

    Science.gov (United States)

    Matsushita, Soyogu; Morikawa, Kazunori; Yamanami, Haruna

    2015-01-01

    Do eyeliner, mascara, and eye shadow actually make the eyes appear larger than they really are? If so, by what percentage? To answer these questions, we used psychophysical experiments. Experiment 1 manipulated the degree of eyeliner (four levels) and mascara (five levels), and measured perceived eye size using a psychophysical procedure called the staircase method. The results showed that both eyeliner and mascara make the eyes appear larger than they really are by up to 6% (13% in area), but their effects are not additive. Eyeliner increased perceived eye size only in the absence of mascara. In the presence of mascara, however, eyeliner has no additional effect. Experiment 2 measured perceived eye size with or without eye shadow and demonstrated that eye shadow increases perceived eye size by about 5% (10% in area). These findings indicate that one mechanism by which makeup and cosmetics alter facial appearances involves inducing visual illusions. In addition, it is suggested that the eye size illusion caused by eyeliner, mascara, and eye shadow uses the same mechanism as that of the Delboeuf illusion, a geometric illusion of assimilation. PMID:26454904

  1. Synthesis of magnetite submicrospheres with tunable size and superparamagnetism by a facile polyol process

    International Nuclear Information System (INIS)

    Magnetite submicrospheres with an average size range of 90–490 nm were obtained by a facile polyol process. The effects of reaction conditions on the morphology and static magnetism of magnetite submicrospheres were studied when the reaction time, the concentration of component, and the types of the solvent or surfactant changed. The average size of primary crystals was controlled by changing the concentration of surfactant thus the superparamagnetism was obtained, meanwhile the average size of secondary clusters was tuned by changing the concentration of ferrous precursor FeCl3·6H2O. The ratio of ethylene glycol and diethylene glycol, the concentration of NaAC, and the reaction time all exhibited novel effects on the morphology of magnetite submicrospheres facilitating our understanding about the synthesis mechanism. The synthesized magnetite submicrospheres were successfully used for photonic crystal. - Highlights: ► Color tunable colloidal crystals were fabricated by a facile polyol process. ► The size of magnetite primary crystals was decreased using high [PAA]. ► Meanwhile the size of magnetite submicrospheres was tuned by changing [FeCl3·6H2O]. ► EG/DEG, [NaAC], and the reaction time all exhibited novel effects

  2. Improved soil particle-size analysis by gamma-ray attenuation

    International Nuclear Information System (INIS)

    The size distribution of particles is useful for physical characterization of soil. This study was conducted to determine whether a new method of soil particle-size analysis by gamma-ray attenuation could be further improved by changing the depth and time of measurement of the suspended particle concentration during sedimentation. In addition to the advantage of nondestructive, undisturbed measurement by gamma-ray attenuation, as compared with conventional pipette or hydrometer methods, the modifications here suggested and employed do substantially decrease the total time for analysis, and will also facilitate total automation and generalize the method for other sedimentation studies. Experimental results are presented for three different Brazilian soil materials, and illustrate the nature of the fine detail provided in the cumulative particle-size distribution as given by measurements obtained during the relatively short time period of 28 min

  3. Chemical composition shape form and size of suspended solids in the atmosphere carried by rain water

    International Nuclear Information System (INIS)

    The interest of this work is to know about shape form, size and chemical composition of the suspended solids in the atmosphere of Toluca city and which are carried by the rains. The harvest of the samples was carried out during january to november 1999. The separation of the particulate matter from the rain water was realized through centrifugation. The solids were analysed by Scanning Electron Microscopy to know the shape form and size and the chemical composition was determined by X-ray dispersive energy in general form and of some particles individually analysed. The p H was measured to the solutions and the quantification of some dissolved ions by the Icp technique was realized. The results of the solids showed C, O, Na, Mg, Al, Si, S, P, K, Ca, Ti and Fe. Moreover they present sizes which varying from a ten of nanometers until some tens of microns. (Author)

  4. Determination of the size of a radiation source by the method of calculation of diffraction patterns

    Science.gov (United States)

    Tilikin, I. N.; Shelkovenko, T. A.; Pikuz, S. A.; Hammer, D. A.

    2013-07-01

    In traditional X-ray radiography, which has been used for various purposes since the discovery of X-ray radiation, the shadow image of an object under study is constructed based on the difference in the absorption of the X-ray radiation by different parts of the object. The main method that ensures a high spatial resolution is the method of point projection X-ray radiography, i.e., radiography from a point and bright radiation source. For projection radiography, the small size of the source is the most important characteristic of the source, which mainly determines the spatial resolution of the method. In this work, as a point source of soft X-ray radiation for radiography with a high spatial and temporal resolution, radiation from a hot spot of X-pinches is used. The size of the radiation source in different setups and configurations can be different. For four different high-current generators, we have calculated the sizes of sources of soft X-ray radiation from X-ray patterns of corresponding objects using Fresnel-Kirchhoff integrals. Our calculations show that the size of the source is in the range 0.7-2.8 μm. The method of the determination of the size of a radiation source from calculations of Fresnel-Kirchhoff integrals makes it possible to determine the size with an accuracy that exceeds the diffraction limit, which frequently restricts the resolution of standard methods.

  5. Overview about the environmental analysis within the project CUTE : Clean urban transport for Europe using fuel cell driven buses

    International Nuclear Information System (INIS)

    Established to demonstrate the readiness of the fuel cell technology as an almost emission-free and low-noise transport system in public transportation, the Clean Urban Transport for Europe (CUTE) represents the first large scale fleet application of fuel cell driven vehicles. The firm IKP is responsible for the evaluation of new technology concerning fuel cell driven buses in its entirety and over its complete life cycle, to ensure that the goals of environmentally friendly and resource saving of transportation are achieved. A comparison with conventional alternatives, such as diesel driven buses, and compressed natural gas buses was performed. Life cycle assessment in accordance with Deutsches Institut fur Normung e.V. (DIN) International Standardization Organization (ISO) 14040 series was used for the ecological, technical and economic analysis. The potential of the new fuel cell technology in the reduction of air polluting emissions such as sulphur dioxide and summer smog causing nitrogen oxides in highly populated inner city areas was investigated, along with the quantification of the abatement of carbon dioxide at European level and contribution to Kyoto commitments. 7 refs., 8 figs

  6. Effect of weed patch size on seed removal by harvester ants

    Directory of Open Access Journals (Sweden)

    Westermann, Paula R.

    2014-02-01

    Full Text Available In dryland cereals in North-eastern Spain, the harvester ant, Messor barbarus L., is responsible for removal of a large proportion of the newly produced weed seeds (40-100%. The probability that seeds will be found by the ants may be influenced by weed patch size. To investigate this source of variability, 30 seed patches were created in each of three, 50 × 50 m, blocks in a cereal field after harvest, by sequentially seeding (10, 16 and 17 August 2010 with 2000 seeds m-2 of Avena sativa L.. Patch size varied from 0.25 to 9 m2. Twenty four hours after seeding, the remaining seeds were collected and seed removal rates estimated. Average seed removal rate was lowest in the smallest (78-94% and highest in the largest patches (99-100%. Differences were mainly caused by the fact that some of the smaller patches (9.7% were not found. However, when patches were found, they were exploited at equal rates (98-100%. As predicted, the probability of finding a patch increased slightly, but significantly, with increasing patch size. When a patch was found, it was almost always fully exploited, resulting in very high seed removal rates, irrespective of patch size. These results indicate that the size of the seed patch is only a minor source of variation influencing this form of biological control of weeds.

  7. Impact of temperature on zinc oxide particle size by using sol-gel process

    International Nuclear Information System (INIS)

    Zinc oxide (ZnO) nanoparticles were prepared and synthesized via sol-gel method, by using citric acid as a precursor. The impact of annealing on the particle size was investigated. Based on the results from the Thermogravimetric Analysis (TGA), three different annealing temperature which is 500, 600 and 700 °C were chosen followed by the characterization of the ZnO nanoparticle by using Powder X-Ray Diffraction (PXRD), Transmission Electron Microscopy (TEM) and Field Emission Scanning Electron Microscopy (FESEM). Results showed that the crystallite size estimated from PXRD increased with the annealing temperature which was hexagonal structure for ZnO. TEM further revealed the same tendency which the Zn NPs size also increased with the annealing temperature

  8. Impact of temperature on zinc oxide particle size by using sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Keanchuan, E-mail: lee.kc@petronas.com.my; Ching, Dennis Ling Chuan, E-mail: dennis.ling@petronas.com.my [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia); Saipolbahri, Zulhilmi Akmal bin, E-mail: zulhilmiakmal@gmail.com [Geoscience and Petroleum Engineering Department, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia); Guan, Beh Hoe, E-mail: beh.hoeguan@petronas.com.my, E-mail: hassan.soleimani@petronas.com.my; Soleimani, Hassan, E-mail: beh.hoeguan@petronas.com.my, E-mail: hassan.soleimani@petronas.com.my

    2014-10-24

    Zinc oxide (ZnO) nanoparticles were prepared and synthesized via sol-gel method, by using citric acid as a precursor. The impact of annealing on the particle size was investigated. Based on the results from the Thermogravimetric Analysis (TGA), three different annealing temperature which is 500, 600 and 700 °C were chosen followed by the characterization of the ZnO nanoparticle by using Powder X-Ray Diffraction (PXRD), Transmission Electron Microscopy (TEM) and Field Emission Scanning Electron Microscopy (FESEM). Results showed that the crystallite size estimated from PXRD increased with the annealing temperature which was hexagonal structure for ZnO. TEM further revealed the same tendency which the Zn NPs size also increased with the annealing temperature.

  9. Determining proportions of lunar crater populations by fitting crater size distribution

    CERN Document Server

    Wang, Nan

    2016-01-01

    We determine the proportions of two mixed crater populations distinguishable by size distributions on the Moon. A "multiple power-law" model is built to formulate crater size distribution $N(D) \\propto D^{-\\alpha}$ whose slope $\\alpha$ varies with crater diameter $D$. Fitted size distribution of lunar highland craters characterized by $\\alpha = 1.17 \\pm 0.04$, $1.88 \\pm 0.07$, $3.17 \\pm 0.10$ and $1.40 \\pm 0.15$ for consecutive $D$ intervals divided by 49, 120 and 251 km and that of lunar Class 1 craters with a single slope $\\alpha = 1.96 \\pm 0.14$, are taken as Population 1 and 2 crater size distribution respectively, whose sum is then fitted to the size distribution of global lunar craters with $D$ between 10 and 100 km. Estimated crater densities of Population 1 and 2 are $44 \\times 10^{-5}$ and $5 \\times 10^{-5}$ km$^{-2}$ respectively, leading to the proportion of the latter $10 \\%$. The results underlines the need for considering the Population 1 craters and the relevant impactors, the primordial main-b...

  10. Regulation of Caenorhabditis elegans body size and male tail development by the novel gene lon-8

    Directory of Open Access Journals (Sweden)

    Korswagen Hendrik C

    2007-03-01

    Full Text Available Abstract Background In C. elegans and other nematode species, body size is determined by the composition of the extracellular cuticle as well as by the nuclear DNA content of the underlying hypodermis. Mutants that are defective in these processes can exhibit either a short or a long body size phenotype. Several mutations that give a long body size (Lon phenotype have been characterized and found to be regulated by the DBL-1/TGF-β pathway, that controls post-embryonic growth and male tail development. Results Here we characterize a novel gene affecting body size. lon-8 encodes a secreted product of the hypodermis that is highly conserved in Rhabditid nematodes. lon-8 regulates larval elongation as well as male tail development. In both processes, lon-8 appears to function independently of the Sma/Mab pathway. Rather, lon-8 genetically interacts with dpy-11 and dpy-18, which encode cuticle collagen modifying enzymes. Conclusion The novel gene lon-8 encodes a secreted product of the hypodermis that controls body size and male ray morphology in C. elegans. lon-8 genetically interacts with enzymes that affect the composition of the cuticle.

  11. Fatigue-related crashes involving express buses in Malaysia: will the proposed policy of banning the early-hour operation reduce fatigue-related crashes and benefit overall road safety?

    Science.gov (United States)

    Mohamed, Norlen; Mohd-Yusoff, Mohammad-Fadhli; Othman, Ilhamah; Zulkipli, Zarir-Hafiz; Osman, Mohd Rasid; Voon, Wong Shaw

    2012-03-01

    Fatigue-related crashes have long been the topic of discussion and study worldwide. The relationship between fatigue-related crashes and time of day is well documented. In Malaysia, the possibility of banning express buses from operating during the early-hours of the morning has emerged as an important consideration for passenger safety. This paper highlights the findings of an impact assessment study. The study was conducted to determine all possible impacts prior to the government making any decision on the proposed banning. This study is an example of a simple and inexpensive approach that may influence future policy-making process. The impact assessment comprised two major steps. The first step involved profiling existing operation scenarios, gathering information on crashes involving public express buses and stakeholders' views. The second step involved a qualitative impact assessment analysis using all information gathered during the profiling stage to describe the possible impacts. Based on the assessment, the move to ban early-hour operations could possibly result in further negative impacts on the overall road safety agenda. These negative impacts may occur if the fundamental issues, such as driving and working hours, and the need for rest and sleep facilities for drivers, are not addressed. In addition, a safer and more accessible public transportation system as an alternative for those who choose to travel at night would be required. The proposed banning of early-hour operations is also not a feasible solution for sustainability of express bus operations in Malaysia, especially for those operating long journeys. The paper concludes by highlighting the need to design a more holistic approach for preventing fatigue-related crashes involving express buses in Malaysia. PMID:22239931

  12. Multi-criteria analysis of alternative-fuel buses for public transportation

    International Nuclear Information System (INIS)

    The technological development of buses with new alternative fuels is considered in this paper. Several types of fuels are considered as alternative-fuel modes, i.e., electricity, fuel cell (hydrogen), and methanol. Electric vehicles may be considered the alternative-fuel vehicles with the lowest air pollution. Hybrid electric vehicles provide an alternate mode, at least for the period of improving the technology of electric vehicles. A hybrid electric vehicle is defined as a vehicle with the conventional internal combustion engine and an electric motor as its major sources of power. Experts from different decision-making groups performed the multiple attribute evaluation of alternative vehicles. AHP is applied to determine the relative weights of evaluation criteria. TOPSIS and VIKOR are compared and applied to determine the best compromise alternative fuel mode. The result shows that the hybrid electric bus is the most suitable substitute bus for Taiwan urban areas in the short and median term. But, if the cruising distance of the electric bus extends to an acceptable range, the pure electric bus could be the best alternative

  13. Pore Size Distribution in Chicken Eggs as Determined by Mercury Porosimetry

    Directory of Open Access Journals (Sweden)

    La Scala Jr N

    2000-01-01

    Full Text Available In this study we investigated the application of mercury porosimetry technique into the determination of porosity features in 28 week old hen eggshells. Our results have shown that the majority of the pores have sizes between 1 to 10 mu m in the eggshells studied. By applying mercury porosimetry technique we were able to describe the porosity features better, by determining a pore size distribution in the eggshells. Here, we introduce mercury porosimetry technique as a new routine technique applied into the study of eggshells.

  14. Pore size evaluation of mesoporous organosilicate films by non-destructive X-ray reflectivity methods

    International Nuclear Information System (INIS)

    200-nm-thick organosilicate films deposited by mixture of tetraethyl orthosilicate (TEOS) and methyltrimethoxysilane (MTMS) dissolving in different cetrimonium bromide (CTAB)/ethanol ratios were characterized in terms of pore size determination and its distribution. Under the toluene ambient, the pores would adsorb the gas hence elevating the whole film density. The X-ray reflectivity (XRR) equipped with mass flow control was utilized to detect the film density increasing. By fitting with Gaussian function and conversing with Kelvin's equation, the pore size was increased from 6.2 to 10.8 Å as the CTAB/ethanol ratio increasing to 0.075. It was attributed to the ethanol and CTAB enhanced the TEOS hollow droplets stability and dissolvability. As the CTAB/ethanol ratio is further increased, the pore size is reversely decreased, owing to the formation of solid microspheres. The non-destructive XRR measurement can evaluate the sub-nano pore sizes and its size distribution, which would fascinate the development and characterization of back-end of line process. (author)

  15. Preparation of Small Particle Sized ZnAl-Hydrotalcite-Like Compounds by Ultrasonic Crystallization

    Institute of Scientific and Technical Information of China (English)

    Xianmei Xie; Xiurong Ren; Jinping Li; Xiaojun Hu; Zhizhong Wang

    2006-01-01

    Ultrasonic technology has been intensively studied recently due to its special features. In this paper, an ultrasonic crystallization method was introduced for the preparation of ZnAl-Hydrotalcite-Like compounds (ZnAl-HTLcs). Samples with high crystallinity, small particle size and narrow particle size distribution were obtained and fully characterized using conventional techniques of XRD, FT-IR and TG-DTA. The results prove that both ultrasonic frequency and ultrasonic power have effects on the sizes of the product particles. By varying the ultrasonic power from 250 W to 88 W, with the ultrasonic frequency fixed at 59 kHz, the median particle size of the samples increased from 0.37μm to 0.82μm. By altering the hydrothermal treatment time from 1 h to 5 h at 110 ℃, the median particle size of ZnAl-HTLcs synthesized via ultrasonic crystallization increased from 0.88 μm to 1.11 μm.

  16. Effects of surfactants on size and structure of amylose nanoparticles prepared by precipitation

    Indian Academy of Sciences (India)

    Yan Dong; Yanjiao Chang; Qian Wang; Jin Tong; Jiang Zhou

    2016-02-01

    The present work investigated the influence of surfactants on size and structure of amylose nanoparticles (ANPs) prepared through precipitation. ANPs were fabricated using absolute ethanol containing surfactants (Tween80, Span80 and mixtures of Tween80 and Span80 with ratios of 25/75, 50/50 and 75/25, respectively) as non-solvents. The obtained ANPs were characterized using dynamic light scattering (DLS), scanning electron microscopy and X-ray diffraction. The results showed that surfactant type, concentration and hydrophilic–lipophilic balance (HLB) value had great impact on size of precipitated ANPs. The smallest ANPs with mean size of 155 nm determined by DLS were obtained by using 0.5% (in proportion of the amylose solution volume) of Tween80/Span80 mixture (HLB = 12.33). The precipitated ANPs possessed the V-type crystalline structure no matter whether using the surfactants or not.

  17. Size modulation of nanocrystalline silicon embedded in amorphous silicon oxide by Cat-CVD

    International Nuclear Information System (INIS)

    Different issues related to controlling size of nanocrystalline silicon (nc-Si) embedded in hydrogenated amorphous silicon oxide (a-SiOx:H) deposited by catalytic chemical vapor deposition (Cat-CVD) have been reported. Films were deposited using tantalum (Ta) and tungsten (W) filaments and it is observed that films deposited using tantalum filament resulted in good control on the properties. The parameters which can affect the size of nc-Si domains have been studied which include hydrogen flow rate, catalyst and substrate temperatures. The deposited samples are characterized by X-ray diffraction, HRTEM and micro-Raman spectroscopy, for determining the size of the deposited nc-Si. The crystallite formation starts for Ta-catalyst around the temperature of 1700 oC.

  18. Microstructural study and size control of iron oxide nanoparticles produced by microemulsion technique

    Science.gov (United States)

    Koutzarova, T.; Kolev, S.; Ghelev, Ch.; Paneva, D.; Nedkov, I.

    2006-05-01

    In this paper we study the possibility to control the size of iron oxide (Fe3O4) nanoparticles by the microemulsion technique. We used a water-in-oil reverse microemulsion system with n-hexadecil trimethylammonium bromide (CTAB) as a cationic surfactant, n-butanol as a co-surfactant, n-hexanol as a continuous oil phase, and aqueous phase. The magnetite nanopowders were synthesized by a single microemulsion technique in which the aqueous phase contains only metal ions (Fe2+ and Fe3+). The particle size of the powders varied in the range of 14-36 nm depending on the preparation conditions. We studied the influence of changing the water/surfactant ratio (W 0 = 5, 10, 15, 20) and the metallic ion (Fe2+ and Fe3+) concentration on the particle size distribution and crystallinity of Fe3O4.

  19. The Cambrian explosion triggered by critical turning point in genome size evolution.

    Science.gov (United States)

    Li, Dirson Jian; Zhang, Shengli

    2010-02-01

    The Cambrian explosion is a grand challenge to science today and involves multidisciplinary study. This event is generally believed as a result of genetic innovations, environmental factors and ecological interactions, even though there are many conflicts on nature and timing of metazoan origins. The crux of the matter is that an entire roadmap of the evolution is missing to discern the biological complexity transition and to evaluate the critical role of the Cambrian explosion in the overall evolutionary context. Here, we calculate the time of the Cambrian explosion by a "C-value clock"; our result quite fits the fossil records. We clarify that the intrinsic reason of genome evolution determined the Cambrian explosion. A general formula for evaluating genome size of different species has been found, by which the genome size evolution can be illustrated. The Cambrian explosion, as a major transition of biological complexity, essentially corresponds to a critical turning point in genome size evolution. PMID:20074549

  20. Modeling group size and scalar stress by logistic regression from an archaeological perspective.

    Directory of Open Access Journals (Sweden)

    Gianmarco Alberti

    Full Text Available Johnson's scalar stress theory, describing the mechanics of (and the remedies to the increase in in-group conflictuality that parallels the increase in groups' size, provides scholars with a useful theoretical framework for the understanding of different aspects of the material culture of past communities (i.e., social organization, communal food consumption, ceramic style, architecture and settlement layout. Due to its relevance in archaeology and anthropology, the article aims at proposing a predictive model of critical level of scalar stress on the basis of community size. Drawing upon Johnson's theory and on Dunbar's findings on the cognitive constrains to human group size, a model is built by means of Logistic Regression on the basis of the data on colony fissioning among the Hutterites of North America. On the grounds of the theoretical framework sketched in the first part of the article, the absence or presence of colony fissioning is considered expression of not critical vs. critical level of scalar stress for the sake of the model building. The model, which is also tested against a sample of archaeological and ethnographic cases: a confirms the existence of a significant relationship between critical scalar stress and group size, setting the issue on firmer statistical grounds; b allows calculating the intercept and slope of the logistic regression model, which can be used in any time to estimate the probability that a community experienced a critical level of scalar stress; c allows locating a critical scalar stress threshold at community size 127 (95% CI: 122-132, while the maximum probability of critical scale stress is predicted at size 158 (95% CI: 147-170. The model ultimately provides grounds to assess, for the sake of any further archaeological/anthropological interpretation, the probability that a group reached a hot spot of size development critical for its internal cohesion.

  1. Size-resolved source apportionment of ambient particles by positive matrix factorization

    Science.gov (United States)

    Han, J. S.; Moon, K. J.; Lee, S. J.; Kim, Y. J.; Ryu, S. Y.; Cliff, S. S.; Yi, S. M.

    2005-07-01

    Size- and time-resolved aerosol samples were collected using an eight-stage DRUM sampler from 29 March to 29 May in 2002 at Gosan, Jeju Island, Korea, which is one of the representative background sites in East Asia. These samples were analyzed using synchrotron X-ray fluorescence for 3-h average concentrations of 19 elements consisting of S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, Br. The size-resolved data sets were then analyzed using the positive matrix factorization (PMF) technique in order to identify possible sources and estimate their contribution to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Fifteen sources were resolved in eight size ranges (0.07-12 µm) and included Chinese aerosol, soil dust, sea salt, biomass burning, coal combustion, oil heating furnace, residual oil-fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter, and volcano emission. PMF analysis of size-resolved source contributions showed that natural sources represented by soil dust, sea salt and Chinese aerosol contributed about 79% to the predicted primary PM mass in the coarse size range (1.15-12 µm). On the other hand, anthropogenic sources such as coal combustion and biomass burning contributed about 60% in the fine size range (0.56-2.5 µm). The diesel vehicle source contributed the most in the ultra-fine size range (0.07-0.56 µm) and was responsible for about 52% of the primary PM mass.

  2. Effect of population size on genetic variation levels in Capparis spinosa (Capparaceae detected by RAPDs

    Directory of Open Access Journals (Sweden)

    Houshang Nosrati

    2012-07-01

    Full Text Available Background: The population size of plants affects on population genetic variation. Materials and Methods: We studied the impact of population size on genetic variation in populations of Capparis spinosa (caper, Capparaceae using RAPDs in East Azerbaijan (Iran. Within-population genetic diversity was estimated based on Nei`s and Shanonn`s diversity using Popgen, and genetic similarity among the populations was studied from a UPGMA dendrogram based the matrix of Nei’s distances obtained through SHAN. Difference in the level genetic variation between small-sized and large-sized populations was tested using Mann-Whitney U test, and correlation between geographical and genetic distances among populations was examined by Pearson test (SPSS, 11.3. Total genetic variation was partitioned into within and among populations based on AMOVA using Arlequin. Results: The polymorphism levels of RAPDs bands among the populations ranged from 48.8% to 81.4%, and within-population Nei’s diversity varied from 0.1667 to 0.2630. Genetic variation in small-sized populations (0.1667 to 0.1809 was significantly lower than the variations in large-sized populations (0.2158 -0.2630 (N= 7, P0.674, Pearson correlation test. Conclusions: Population size has a dramatic impact on its genetic diversity. The results revealed that fragmentation of caper population in the study region has most likely occurred recently. The low genetic diversity revealed within caper populations indicates high risk of extinction and suggests that urgent conservation action is needed to recover diversity in these populations.

  3. Overestimation of test performance by ROC analysis: Effect of small sample size

    International Nuclear Information System (INIS)

    New imaging systems are often observer-rated by ROC techniques. For practical reasons the number of different images, or sample size (SS), is kept small. Any systematic bias due to small SS would bias system evaluation. The authors set about to determine whether the area under the ROC curve (AUC) would be systematically biased by small SS. Monte Carlo techniques were used to simulate observer performance in distinguishing signal (SN) from noise (N) on a 6-point scale; P(SN) = P(N) = .5. Four sample sizes (15, 25, 50 and 100 each of SN and N), three ROC slopes (0.8, 1.0 and 1.25), and three intercepts (0.8, 1.0 and 1.25) were considered. In each of the 36 combinations of SS, slope and intercept, 2000 runs were simulated. Results showed a systematic bias: the observed AUC exceeded the expected AUC in every one of the 36 combinations for all sample sizes, with the smallest sample sizes having the largest bias. This suggests that evaluations of imaging systems using ROC curves based on small sample size systematically overestimate system performance. The effect is consistent but subtle (maximum 10% of AUC standard deviation), and is probably masked by the s.d. in most practical settings. Although there is a statistically significant effect (F = 33.34, P<0.0001) due to sample size, none was found for either the ROC curve slope or intercept. Overestimation of test performance by small SS seems to be an inherent characteristic of the ROC technique that has not previously been described

  4. Microfluidic sorting of protein nanocrystals by size for X-ray free-electron laser diffraction

    Directory of Open Access Journals (Sweden)

    Bahige G. Abdallah

    2015-07-01

    Full Text Available The advent and application of the X-ray free-electron laser (XFEL has uncovered the structures of proteins that could not previously be solved using traditional crystallography. While this new technology is powerful, optimization of the process is still needed to improve data quality and analysis efficiency. One area is sample heterogeneity, where variations in crystal size (among other factors lead to the requirement of large data sets (and thus 10–100 mg of protein for determining accurate structure factors. To decrease sample dispersity, we developed a high-throughput microfluidic sorter operating on the principle of dielectrophoresis, whereby polydisperse particles can be transported into various fluid streams for size fractionation. Using this microsorter, we isolated several milliliters of photosystem I nanocrystal fractions ranging from 200 to 600 nm in size as characterized by dynamic light scattering, nanoparticle tracking, and electron microscopy. Sorted nanocrystals were delivered in a liquid jet via the gas dynamic virtual nozzle into the path of the XFEL at the Linac Coherent Light Source. We obtained diffraction to ∼4 Å resolution, indicating that the small crystals were not damaged by the sorting process. We also observed the shape transforms of photosystem I nanocrystals, demonstrating that our device can optimize data collection for the shape transform-based phasing method. Using simulations, we show that narrow crystal size distributions can significantly improve merged data quality in serial crystallography. From this proof-of-concept work, we expect that the automated size-sorting of protein crystals will become an important step for sample production by reducing the amount of protein needed for a high quality final structure and the development of novel phasing methods that exploit inter-Bragg reflection intensities or use variations in beam intensity for radiation damage-induced phasing. This method will also

  5. UNIFICATION SCHEME OF RADIO GALAXIES AND QUASARS FALSIFIED BY THEIR OBSERVED SIZE DISTRIBUTIONS

    International Nuclear Information System (INIS)

    In the currently popular orientation-based unified scheme, a radio galaxy appears as a quasar when its principal radio-axis happens to be oriented within a certain cone opening angle around the observer's line of sight. Due to geometrical projection, the observed sizes of quasars should therefore appear smaller than those of radio galaxies. We show that this simple, unambiguous prediction of the unified scheme is not borne out by the actually observed angular sizes of radio galaxies and quasars. Except in the original 3CR sample, based on which the unified scheme was proposed, in other much larger samples no statistically significant difference is apparent in the size distributions of radio galaxies and quasars. The population of low-excitation radio galaxies with apparently no hidden quasars inside, which might explain the observed excess number of radio galaxies at low redshifts, cannot account for the absence of any foreshortening of the sizes of quasars at large redshifts. On the other hand, from infrared and X-ray studies, there is evidence of a hidden quasar within a dusty torus in many radio galaxies, at z > 0.5. It is difficult to reconcile this with the absence of foreshortening of quasar sizes at even these redshifts, and perhaps one has to allow that the major radio axis may not have anything to do with the optical axis of the torus. Otherwise, to resolve the dichotomy of radio galaxies and quasars, a scheme quite different from the present might be required.

  6. Comparison of lesion size estimated by dynamic MR imaging, mammography and histopathology in breast neoplasms

    International Nuclear Information System (INIS)

    To evaluate the accordance of size measurements of malignant breast lesions 65 women with 76 malignant lesions were preoperatively examined with triple diagnosis (mammography was performed in three views with additional views if necessary) and dynamic MR imaging using a subtraction technique with a 3D T1-weighted sequence. Maximum lesion size at histopathology was used as gold standard and compared with maximum lesion size at MRI and mammography. All measurements were made independently for each method. Histopathology verified 48 invasive, 5 in situ, and 23 mixed lesions. No significant difference was found for the pure invasive lesions (p=0.366). In the mixed lesions a slightly better result for MRI was indicated (p=0.116), although there was a great spread. Only five pure in situ lesions were assessed, too few to draw any statistical conclusions (p>0.5). An overall difference indicated a slight superiority of MRI (p=0.097). The MR imaging and mammography are both good at measuring the size of detected invasive breast malignancies. The total sizes of mixed lesions are frequently underestimated by both MRI and mammography, although the invasive parts were equally well described and measured with both methods. (orig.)

  7. Pitfalls and novel applications of particle sizing by dynamic light scattering.

    Science.gov (United States)

    Fischer, Karl; Schmidt, Manfred

    2016-08-01

    After briefly introducing the theoretical equations for DLS based particle size analysis, the need for angular dependent DLS investigations is emphasized to obtain correct particle sizes. Practical examples are given that demonstrate the possible magnitudes of errors in particle size if DLS is measured at one large scattering angle, only, as done by essentially all, most frequently utilized commercial "single angle" particle sizers. The second part is focused on a novel DLS application to sensitively trace (nano)particle interactions with concentrated blood serum or plasma that leads to the formation of large aggregates in a size regime of ≫100 nm. Most likely, such aggregates originate from protein induced bridging of nanoparticles, since it is well known that serum proteins adsorb onto the surface of essentially all nanoparticles utilized in medical applications. Thus, the protein corona around nanoparticles does not only change their biological identity but to a large extend also their size, thus possibly affecting biodistribution and in vivo circulation time. PMID:27179435

  8. Understanding of cluster size deviation by measuring the dimensions of cluster jet from conical nozzles

    Science.gov (United States)

    Chen, Guanglong; Geng, Xiaotao; Xu, Hongxia; Mi, Yiming; Zhang, Xiuli; Wang, Lili; Kim, Dong Eon

    2013-03-01

    This work aims to understand the cluster size deviation from the prediction by an existing scaling law for conical nozzles. The dimensions of cluster jet at different heights above a nozzle along the direction of gas flow are measured. This study indicates that the dimension of cluster jet is underestimated in the existing scaling law and this under-estimation leads to the over-estimation of the equivalent diameter of conical nozzle. Thus the underestimation of the dimension of cluster jet may be one of possible factors responsible for the cluster size deviation (the degree of the deviation depends on details of cluster jet).

  9. Austenite grain size control of a hot working tool steel by addition of niobium

    International Nuclear Information System (INIS)

    The substitution of vanadium by niobium for controlling the austenite grain size of a hot working tool steel was studied, using the addition of the same atomic percentage as a criterion. The austenitising temperatures ranged from 850 to 1.2000C. At low austenitising temperature, both vanadium and niobium are effective in producing small grain size. At high austenitising temperatures, niobium was more effective than vanadium. Possible causes of this difference and the occurrence of coarse niobium carbide in the niobium steel are discussed on the basis of the difference in solubility between niobium and vanadium carbides

  10. Size Effect of Lattice Thermal Conductivity Across Nanoscale Thin Films by Molecular Dynamics Simulations

    Institute of Scientific and Technical Information of China (English)

    FENG Xiao-Li; LI Zhi-Xin; GUO Zeng-Yuan

    2001-01-01

    Thermal conductivity in the normal direction of ultra-thin dielectric films is predicted by molecular dynamics calculations for argon crystal. For film thicknesses of about 2-10nm within which real measurements cannot yet be implemented, the size dependence of lattice thermal conductivity is captured and a remarkable thermal conductivity drop is found as compared with bulk experimental data. This size effect demonstrates that phonon-boundary scattering in thin films may also be very significant at high temperatures even above the Debye temperature. The influence of different potential models is examined according to the comparison between results from the Lennard-Jones potential and a soft-sphere potential.

  11. Can adult and juvenile European rabbits be differentiated by their pellet sizes?

    Science.gov (United States)

    Delibes-Mateos, Miguel; Rouco, Carlos; Villafuerte, Rafael

    2009-03-01

    Recently, a new method for differentiating juvenile and adult rabbits based on faecal pellet size was published. According to this method, pellets >6 mm diameter are inferred to be deposited by adults, while those test the accuracy of this methodology. Twelve adult rabbits were housed in individual outdoor cages and their pellets were removed every day for 10 consecutive days. Pellets were separated using a sieve according to their size and counted. Results showed that adult rabbits produce pellets >6 mm diameter in the same proportion as those 6 mm, whereas others deposit mostly pellets animals in the absence of validating studies.

  12. Improvement in accuracy of defect size measurement by automatic defect classification

    Science.gov (United States)

    Samir, Bhamidipati; Pereira, Mark; Paninjath, Sankaranarayanan; Jeon, Chan-Uk; Chung, Dong-Hoon; Yoon, Gi-Sung; Jung, Hong-Yul

    2015-10-01

    The blank mask defect review process involves detailed analysis of defects observed across a substrate's multiple preparation stages, such as cleaning and resist-coating. The detailed knowledge of these defects plays an important role in the eventual yield obtained by using the blank. Defect knowledge predominantly comprises of details such as the number of defects observed, and their accurate sizes. Mask usability assessment at the start of the preparation process, is crudely based on number of defects. Similarly, defect size gives an idea of eventual wafer defect printability. Furthermore, monitoring defect characteristics, specifically size and shape, aids in obtaining process related information such as cleaning or coating process efficiencies. Blank mask defect review process is largely manual in nature. However, the large number of defects, observed for latest technology nodes with reducing half-pitch sizes; and the associated amount of information, together make the process increasingly inefficient in terms of review time, accuracy and consistency. The usage of additional tools such as CDSEM may be required to further aid the review process resulting in increasing costs. Calibre® MDPAutoClassify™ provides an automated software alternative, in the form of a powerful analysis tool for fast, accurate, consistent and automatic classification of blank defects. Elaborate post-processing algorithms are applied on defect images generated by inspection machines, to extract and report significant defect information such as defect size, affecting defect printability and mask usability. The algorithm's capabilities are challenged by the variety and complexity of defects encountered, in terms of defect nature, size, shape and composition; and the optical phenomena occurring around the defect [1]. This paper mainly focuses on the results from the evaluation of Calibre® MDPAutoClassify™ product. The main objective of this evaluation is to assess the capability of

  13. Optimal Inspection Policy for Three-state Systems Monitored by Variable Sample Size Control Charts

    OpenAIRE

    Wu, Shaomin

    2011-01-01

    This paper presents the expected long-run cost per unit time for a system monitored by an adaptive control chart with variable sample sizes: if the control chart signals that the system is out of control, the sampling which follows will be conducted with a larger sample size. The system is supposed to have three states: in-control, out-of-control, and failed. Two levels of repair are applied to maintain the system. A minor repair will be conducted if an assignable cause is c...

  14. Direct U isotope analysis in μm-sized particles by LA-MC-ICPMS

    International Nuclear Information System (INIS)

    Full text: The knowledge of the isotopic composition of individual μm-sized hot particles is of great interest especially for strengthened nuclear safeguards in order to identify undeclared nuclear activities. We present the potential of a 'Nu Plasma HR' MC-ICPMS coupled to a New Wave 'UP 193' laser ablation (LA) system for the direct analysis of U isotope abundance ratios in individual μm-sized particles. The ability to determine 234U/238U and 235U/238U isotope ratios was successfully demonstrated in the NUSIMEP-6 interlaboratory comparison, which was organized by the IRMM (Geel, Belgium). (author)

  15. Gold Nanoparticles Size Design and Control by Poly(N,N′-diethylaminoethyl methacrylate)

    OpenAIRE

    Cortez-Lemus, Norma A.; Angel Licea-Claverie; Francisco Paraguay-Delgado; Gabriel Alonso-Nuñez

    2015-01-01

    Poly(N,N′-diethylaminoethyl methacrylate) (PDEAEM) with different molecular weights was used to stabilize gold nanoparticles (AuNPs) obtained by in situ reduction of tetrachloroauric acid using citrates under acidic conditions and in organic/alcoholic medium. The influence of the pH value on gold nanoparticle size in the presence of PDEAEM was investigated. Results show that the pH of the reacting mixture has a dramatic effect on the size, polydispersity, and morphology of the resulting AuNPs...

  16. INSTALLATION FOR LARGE SIZE STAMP HARDENING TRANINIG BY WATER-AIR MIXTURE

    Directory of Open Access Journals (Sweden)

    L. A. Glazkov

    2009-01-01

    Full Text Available The BNTU has developed a technological process for large-size stamp hardening by means of a water-air mixture.  The  basic  requirements  imposed on an hardening  installation using  a  water-air mixture are the following: provision of smooth cooling of a part in order to achieve the required  hardness and structure; possibility of machining parts of various sizes; change of modes for machining parts of various grades of steel according to any hardness rate.The peculiar features of the given installation are: a presence of microprocessor control of water-air mixture supply, possibility of simultaneous machining of a stamp set (2 parts and position change of parts to be hardened in the process of thermal treatment.Installation for large-sized stamp hardening has been manufactured and introduced at theMinskplant of special tools and machining attachments.

  17. SEE characteristics of small feature size devices by using laser backside testing

    Institute of Scientific and Technical Information of China (English)

    Feng Guoqiang; Shangguan Shipeng; Ma Yingqi; Han Jianwei

    2012-01-01

    This paper presents single event upset (SEU) and single event latch-up (SEL) characteristics of small feature size devices by laser backside testing method,which is dedicated to dealing with the increasing metal layers on the front side of integrated circuits.The influence of test data pattern on SEU threshold and cross-section is investigated.The supply current state of micro latch-up for deep sub-micron SRAM is described.The laser energy thresholds were correlated to heavy ion thresholds LET to determine an empirical relationship between laser energy threshold and heavy ion LET.This empirical relationship was used to estimate the equivalent laser LETs for devices fabricated in small feature sizes.Moreover,the SEU of a Power PC CPU fabricated with 90 nm SOI CMOS process has been tested,which indicates that the laser backside method could be used to evaluate SOI small feature size devices.

  18. Evaluation of the effective thermal conductivity of composite polymers by considering the filler size distribution law

    Institute of Scientific and Technical Information of China (English)

    Sorin HOLOTESCU; Floriana D.STOIAN

    2009-01-01

    We present an empirical model for the effective thermal conductivity(ETC)of a polymer composite that includes dependency on the filler size distribution-chosen as the Rosin-Rammler distribution.The ETC is determined based on certain hypotheses that connect the behavior of a real composite matefial A.to that of a model composite material B,filled with mono-dimensional filler.The application of these hypotheses to the Maxwell model for ETC is presented.The validation of the new model and its characteristic equation was carried out using experimental data from the reference.The comparison showed that by using the size distribution law a very good fit between the equation of the new model(the size distribution model for the ETC)and the reference experimental results is obtained,even for high volume fractions,up to about 50%.

  19. Finding Mars-Sized Planets in Inner Orbits of Other Stars by Photometry

    Science.gov (United States)

    Borucki, W.; Cullers, K.; Dunham, E.; Koch, D.; Mena-Werth, J.; Cuzzi, Jeffrey N. (Technical Monitor)

    1995-01-01

    High precision photometry from a spaceborne telescope has the potential of discovering sub-earth sized inner planets. Model calculations by Wetherill indicate that Mars-sized planets can be expected to form throughout the range of orbits from that of Mercury to Mars. While a transit of an Earth-sized planet causes a 0.084% decrease in brightness from a solar-like star, a transit of a planet as small as Mars causes a flux decrease of only 0.023%. Stellar variability will be the limiting factor for transit measurements. Recent analysis of solar variability from the SOLSTICE experiment shows that much of the variability is in the UV at planet as small as Mars should be reliably detectable. If Wetherill's models are correct in postulating that Mars-like planets are present in Mercury-like orbits, then a six year search should be able to find them.

  20. Colony Size of Phaeocystis Antarctica (Prymnesiophyceae) as Influenced by Zooplankton Grazers

    Science.gov (United States)

    The haptophyte Phaeocystis antarctica is a dominant phytoplankton species in the Ross Sea, Antarctica, and exists as solitary cells and mucilaginous colonies that differ by several orders of magnitude in size. Recent studies with P. globosa suggested that colony formation and enl...

  1. Gold Nanoparticles Size Design and Control by Poly(N,N′-diethylaminoethyl methacrylate

    Directory of Open Access Journals (Sweden)

    Norma A. Cortez-Lemus

    2015-01-01

    Full Text Available Poly(N,N′-diethylaminoethyl methacrylate (PDEAEM with different molecular weights was used to stabilize gold nanoparticles (AuNPs obtained by in situ reduction of tetrachloroauric acid using citrates under acidic conditions and in organic/alcoholic medium. The influence of the pH value on gold nanoparticle size in the presence of PDEAEM was investigated. Results show that the pH of the reacting mixture has a dramatic effect on the size, polydispersity, and morphology of the resulting AuNPs. Moreover, the size of the nanoparticles (NPs may be modified by changing the solution’s pH or by changing the solvent type. Electron microscope images showed that the sizes of AuNPs coated with PDEAEM were not sensitive to the variation of the polymer molecular weight in the range between 9000 and 29300 g/mol; however their aggregation behavior depended strongly on the polymer molecular weight as revealed by dynamic light scattering studies. AuNPs stabilized with PDEAEM (AuNP@PDEAEM are stable in water at acidic pH and in organic polar solvents.

  2. High sintering resistance of size-selected platinum cluster catalysts by suppressed ostwald ripening

    DEFF Research Database (Denmark)

    Wettergren, Kristina; Schweinberger, Florian F.; Deiana, Davide;

    2014-01-01

    different supports exhibit remarkable intrinsic sintering resistance even under reaction conditions. The observed stability is related to suppression of Ostwald ripening by elimination of its main driving force via size-selection. This study thus constitutes a general blueprint for the rational design of...

  3. Gold nanoparticle assemblies of controllable size obtained by hydroxylamine reduction at room temperature

    International Nuclear Information System (INIS)

    Colloidal nanoparticle assemblies (NPAs) were obtained in a one-step procedure, by reduction of HAuCl4 by hydroxylamine hydrochloride, at room temperature, without the use of any additional nucleating agent. By changing the order of the reactants, NPAs with mean size of ∼20 and ∼120 nm were obtained. Because of their size and irregular popcorn like shape, the larger size NPAs show absorption in the NIR spectral region. The building blocks of the resulted nanoassemblies are spherical nanoparticles with diameters of 4–8 and 10–30 nm, respectively. Moreover, by stabilizing the colloid with bovine serum albumin at different time moments after synthesis, NPAs of controlled size between 20 and 120 nm, could be obtained. The NPAs were characterized using UV–Vis spectroscopy, TEM and SEM electron microscopies. In addition, the possibility of using the here proposed NPAs as surface-enhanced Raman scattering (SERS) substrate was assessed and found to provide a higher enhancement compared to conventional citrate-reduced nanoparticles

  4. Gold nanoparticle assemblies of controllable size obtained by hydroxylamine reduction at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tódor, István Sz.; Szabó, László; Marişca, Oana T.; Chiş, Vasile; Leopold, Nicolae, E-mail: nicolae.leopold@phys.ubbcluj.ro [Babeş-Bolyai University, Faculty of Physics (Romania)

    2014-12-15

    Colloidal nanoparticle assemblies (NPAs) were obtained in a one-step procedure, by reduction of HAuCl{sub 4} by hydroxylamine hydrochloride, at room temperature, without the use of any additional nucleating agent. By changing the order of the reactants, NPAs with mean size of ∼20 and ∼120 nm were obtained. Because of their size and irregular popcorn like shape, the larger size NPAs show absorption in the NIR spectral region. The building blocks of the resulted nanoassemblies are spherical nanoparticles with diameters of 4–8 and 10–30 nm, respectively. Moreover, by stabilizing the colloid with bovine serum albumin at different time moments after synthesis, NPAs of controlled size between 20 and 120 nm, could be obtained. The NPAs were characterized using UV–Vis spectroscopy, TEM and SEM electron microscopies. In addition, the possibility of using the here proposed NPAs as surface-enhanced Raman scattering (SERS) substrate was assessed and found to provide a higher enhancement compared to conventional citrate-reduced nanoparticles.

  5. Computer Simulation of Packing of Particles with Size Distributions Produced by Fragmentation Processes

    OpenAIRE

    Martin Martin, Miguel Angel; Muñoz Ortega, Francisco Javier; Reyes Castro, Miguel E.; Taguas Coejo, Francisco Javier

    2015-01-01

    Fragmentation schemes inspired by theoretical results and conjectures of Kolmogorov are applied to produce particle size distributions of different natures, depending on fragmentation parameters. A two-dimensional computer simulation method of packing is applied to the resulting distributions and the void fraction is evaluated. The relationship between the void fraction and characteristic parameters of the fragmentation process is studied.

  6. Personnel role by implementing anti-crisis programs in small and medium-size enterprises

    Directory of Open Access Journals (Sweden)

    Pak Andrey Borisovitch

    2011-08-01

    Full Text Available To recover from crisis, small and medium-size enterprises have to develop anti-crisis plans and programs and to monitor the implementation process. The implementation efficiency is provided by the personnel which needs appraisal, motivation and development.

  7. M(H) dependence and size distribution of SPIONs measured by atomic magnetometry

    CERN Document Server

    Colombo, Simone; Grujic, Zoran D; Dolgovskiy, Vladimir; Weis, Antoine

    2016-01-01

    We demonstrate that the quasistatic recording of the magnetic excitation function M(H) of superparamagnetic iron oxide magnetic nanoparticle (SPION) suspensions by an atomic magnetometer allows a precise determination of the sample's iron mass content mFe and the particle size distribution.

  8. Effect of alkali on the size dispersity of mammalian DNA measured by filter elution

    International Nuclear Information System (INIS)

    DNA from unirradiated and irradiated cultured 9L rat brain tumor cells was held for varying times in low ionic strength solutions at pH 11.0, 12.3, or 12.9. The effect of this exposure to alkali on the DNA size distribution was determined by comparing the DNA filter elution profiles obtained experimentally with those theoretically predicted for monodispersed and random distributions. At pH 12.3 or 12.9, DNA from cells irradiated with 300 rad eluted with first-order kinetics corresponding to a random DNA was exposed to pH 12.3 for 24 h. At pH 12.3 or 12.9, DNA from unirradiated cells eluted initially with complex kinetics that later became linear (18-21 h for pH 12.3 or 13-15 h for pH 12.9), characteristic of a monodispersed DNA size distribution. The median size of the distribution decreased if the irradiated DNA size distribution. Holding either unirradiated or irradiated DNA at pH 11.0, below the critical unwinding pH, produced no effect on the elution profiles. Analysis of these filter elution data indicated that after sufficient exposure to pH 12.3 or 12.9, undamaged DNA molecules from mammalian cells elute as a single-stranded monodispersed size distribution of approx.1 x 1010 daltons. While the possibility cannot be completely eliminated that this monodispersed size represents an upper limit determined by physical forces, these results, in conjunction with those obtained using other techniques, lend credence to the existence of a nonrandom higher-order structure in mammalian chromosomal DNA

  9. Fundamental study of computed tomography (CT), 5. Measurement of size by CT

    Energy Technology Data Exchange (ETDEWEB)

    Katakura, T.; Kimura, K.; Suzuki, K.; Ito, M.; Okuaki, K. (Fukushima Medical Coll. (Japan))

    1980-08-01

    Discussion was made on errors when the size of objects were measured on CT images, comparing among various measurement methods. The measured object was an acryl pipe of 47.95 mm in external diameter and 27.65 mm in internal diameter, in which water and alchol were stuffed. CT scanning of this acryl pipe was performed at 90/sup 0/, 60/sup 0/, and 30/sup 0/ of angles between an acryl pipe and CT slice plane, and the size of this pipe was measured on CT images by three methods, (1) CT values profile, (2) recognition of multiformat images, and (3) enhancement curves of multiformat images. CT images were taken in slice thickness of 14 and 17 mm. As a result, No. 1 method was the best. When slice thickness was thin, measurement errors were small, even on CT images taken at small angles to the slice plane. When the size of the object was measured on multiformat images, it was better to take CT images at window level with intermediate CT values between two adjacent objects. In case of measurement by recognition, measurement errors became smallest when the size of object were measured on multiformat images with the smallest window width at the intermediate window level. Clinically, it was easy to use such a method that after measuring by many examiners on CT images taken with the widest window width at the most adequate possible window level, then average out the measured values.

  10. Size Characterization of Colloidal Platinum Nanoparticles by MALDI-TOF Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Navin, Jason K.; Grass, Michael E.; Somorjai, Gabor A.; Marsh, Anderson L.

    2009-08-15

    In this work, matrix assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) has been utilized to characterize colloidal platinum nanoparticles synthesized in the 1-4 nm size range. The nanoparticles were prepared via a solution-based method in which the size could be controlled by varying reaction conditions, such as the alcohol used as the reductant. Poly(vinylpyrrolidone), or PVP, (MW = 29,000 g/mol) was employed as a capping agent to stabilize the synthesized nanoparticles in solution. A model for determining the size of the metallic nanoparticle core from MALDI-TOF mass spectra has been developed and verified through correlation with particle sizes from transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements. In this model it was assumed that 1.85 nm nanoparticles are capped by one PVP chain, which was verified through experiments performed with capped and uncapped nanoparticles. Larger nanoparticles are capped by either two (2.60 and 2.94 nm) or three (3.69 nm) PVP chains. These findings clearly indicate the usefulness of MALDI-TOF MS as a technique for fully characterizing nanoscale materials in order to elucidate structure-property relationships.

  11. Replicon sizes in mammalian cells as estimated by an x-ray plus bromodeoxyuridine photolysis method

    International Nuclear Information System (INIS)

    A new method is described for estimating replicon sizes in mammalian cells. Cultures were pulse labeled with [3H]thymidine ([3H]TdR) and bromodeoxyuridine (BrDUrd) for up to 1 h. The lengths of the resulting labeled regions of DNA, L/sub obs/, were estimated by a technique wherein the change in molecular weight of nascent DNA strands, induced by 313 nm light, is measured by velocity sedimentation in alkaline sucrose gradients. If cells are exposed to 1,000 rads of x rays immediately before pulse labeling, initiation of replicon operation is blocked, although chain elongation proceeds almost normally. Under these conditions L/sub obs/ continues to increase only until operating replicons have completed their replication. This value for L/sub obs/ then remains constant as long as the block to initiation remains and represents an estimate for the average size of replicons operating in the cells before x irradiation. For human diploid fibroblasts and human HeLa cells this estimated average size is approximately 17 μM, whereas for Chinese hamster ovary cells, the average replicon size is about 42 μM

  12. Structure and properties of nano-sized Eurofer 97 steel obtained by hydrostatic extrusion

    International Nuclear Information System (INIS)

    Full text of publication follows: Properties of engineering materials strongly depend on their microstructure. This in particular applies to the size of grains and/or particles in metals, which influence such properties as hardness, flow stress, toughness and creep. Recently, a large interest has been attracted to the so called nano-materials, characterized by the size of grains/particles below 100 nm. Such nano-scaled structures can be obtained in metals by methods of severe plastic deformation, SPD. Among these methods, hydrostatic extrusion offers the potential for producing homogeneous, fully-dense bulk materials in a variety of forms. Hydrostatic extrusion permits also processing of hard-deformable metals (hydrostatic pressure inhibits crack formation) and consolidation of powders. The objective of the present work was to apply hydrostatic extrusion to Eurofer 97 steel - a fusion relevant material. Samples were hydro-statically extruded in a multi-step process with the total true strain of about 4. Microstructure observations via light and transmission electron microscopy revealed significant grain size refinement and changes in carbides size and distribution. This resulted in substantial changes in mechanical properties of the material which were evaluated by hardness measurements, tensile and impact tests. Thermal stability of these properties was also determined. The results are discussed in terms of microstructure properties relationship. Application potential of nano-Eurofer 97 is also discussed. (authors)

  13. Nanoscale size effect on surface spin canting in iron oxide nanoparticles synthesized by the microemulsion method

    International Nuclear Information System (INIS)

    Uniformly sized and crystalline iron oxide nanoparticles (IONPs) with spinel structure and mean diameters of about 3, 6 and 9 nm were synthesized in high yield using the microemulsion route at room temperature. The nanoparticles (NPs) were stabilized in situ by organic surfactant molecules which acted both as a stabilizer of the microemulsion system and as a capping layer of the NP surface. NP size control was attained by careful adjustment of the preparation conditions. The structure, morphology and NP size distribution were investigated by x-ray diffraction, transmission electron microscopy and scanning electron microscopy. A particular effort was devoted in this work to study the effect of size and capping of these NPs on their magnetic structure by in-field Mössbauer spectroscopy at 4.2 K. The mean canting angle (relative to the applied field direction) of the Fe spins was observed to increase with decreasing NP size due to the enhanced surface-to-volume ratio. Comparing bare and capped NPs of the same diameter, we verified that the spin canting was not affected by the organic capping. This implied almost identical magnetic orientations of bare and capped NPs. Simultaneously, the capping material was capable of preventing agglomeration effects which can occur in case of direct particle contact. Using a core/shell model, we showed that spin canting originated from the surface shell of the NPs. Furthermore, the Mössbauer spectral parameters provided evidence for the existence of a high fraction of Fe3O4 (magnetite) in the IONP. (paper)

  14. Charging of Individual Micron-Size Interstellar/Planetary Dust Grains by Secondary Electron Emissions

    Science.gov (United States)

    Tankosic, D.; Abbas, M. M.

    2012-01-01

    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with UV/X-ray radiation, as well as by electron/ion impact. Knowledge of physical and optical properties of individual dust grains is required for understanding of the physical and dynamical processes in space environments and the role of dust in formation of stellar and planetary systems. In this paper, we discuss experimental results on dust charging by electron impact, where low energy electrons are scattered or stick to the dust grains, thereby charging the dust grains negatively, and at sufficiently high energies the incident electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Currently, very limited experimental data are available for charging of individual micron-size dust grains, particularly by low energy electron impact. Available theoretical models based on the Sternglass equation (Sternglass, 1954) are applicable for neutral, planar, and bulk surfaces only. However, charging properties of individual micron-size dust grains are expected to be different from the values measured on bulk materials. Our recent experimental results on individual, positively charged, micron-size lunar dust grains levitated in an electrodynamic balance facility (at NASA-MSFC) indicate that the SEE by electron impact is a complex process. The electron impact may lead to charging or discharging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration (e.g. Abbas et al, 2010). Here we discuss the complex nature of SEE charging properties of individual micron-size lunar dust grains and silica microspheres.

  15. Comparison of Grain Size in Plain Carbon Hot-Rolled Sheets Manufactured by CSP and Conventional Rolling Processing%Comparison of Grain Size in Plain Carbon Hot-Rolled Sheets Manufactured by CSP and Conventional Rolling Processing

    Institute of Scientific and Technical Information of China (English)

    ZHU Xue-song; ZHU Guo-hui; MAO Wei-min

    2012-01-01

    Average grain size and grain size distribution in as hot-rolled SPHC, SPHD, and SPHE sheets manufac- tured by compact strip production (CSP) processing and traditional continuous casting and rolling (CCR) processing respectively were investigated by quantitative metallographic method. The results show that the average grain size and distribution width of grain size in sheets manufactured by CSP processing was obviously larger than that by CCR processing. It was analyzed that multi-phase transformation and high reduction ratio in CCR processing resulted in refining grain size, which would be dominant reason for controlling grain size. In plain carbon steels such as SPHC, SPHD and SPHE, the effect of fine precipitation in CSP on behavior of deformation and recrystallization of austenite during roiling, and consequent refinement of grain size seem not to be as important as the effect of reheating and roughing in CCR processing. Homogenizing in reheating and refining grain size in roughing in CCR processing would refine final grain size and also make grain size homogenized, Very coarse grain size would result in mixed grain size, large distribution width of grain size due to interaction of static and dynamic recrystallization in CSP processing

  16. Nano-sized Li4Ti5O12 anode material with excellent performance prepared by solid state reaction: The effect of precursor size and morphology

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Nano-sized Li4Ti5O12 has been prepared through solid state reaction by using axiolitic TiO2 as precursor. • The prepared nano-sized Li4Ti5O12 anode material shows excellent electrochemical performance. • The utilization of precursor with special morphology and size is one of the useful ways to prepare more active electrode materials. - Abstract: Spinel nano-sized Li4Ti5O12 anode material of secondary lithium-ion battery has been successfully prepared by solid state reaction using axiolitic TiO2 assembled by 10–20 nm nanoparticles and Li2CO3 as precursors. The synthesis condition, grain size effect and corresponding electrochemical performance of the special Li4Ti5O12 have been studied in comparison with those of the normal Li4Ti5O12 originated from commercial TiO2. We also propose the mechanism that using the nano-scaled TiO2 with special structure and unexcess Li2CO3 as precursors can synthesize pure phase nano-sized Li4Ti5O12 at 800 °C through solid state reaction. The prepared nano-sized Li4Ti5O12 anode material for Li-ion batteries shows excellent capacity performance with rate capacity of 174.2, 164.0, 157.4, 146.4 and 129.6 mA h g−1 at 0.5, 1, 2, 5 and 10 C, respectively, and capacity retention of 95.1% after 100 cycles at 1 C. In addition, the specific capacity fade for the cell with the different Li4Ti5O12 active materials resulted from the increase of internal resistance after 100 cycles is compared

  17. Formation of bimetallic nanoalloys by Au coating of size-selected Cu clusters

    International Nuclear Information System (INIS)

    Bimetallic clusters display new characteristics that could not be obtained by varying either the size of pure metallic systems or the composition of bulk bimetals alone. Coating of pre-deposited clusters by vapour deposition is a typical synthesis process of bimetallic clusters. Here, we have demonstrated that hierarchical, gold cluster-decorated copper clusters as well as both heterogeneous and homogeneous Cu–Au bimetallic clusters (4.6 to 10.7 nm) can be prepared by coating pre-deposited, size-selected Cu5000 (4.6 ± 0.2 nm) with Au evaporation at various temperatures. These bimetallic clusters were analyzed by aberration-corrected scanning transmission electron microscopy and associated electron energy loss spectroscopy. The results indicate that the growth of bimetallic clusters is controlled by a competition between nucleation and diffusion of the coating Au atoms.

  18. Atypical BCS-BEC crossover induced by quantum-size effects

    Science.gov (United States)

    Shanenko, A. A.; Croitoru, M. D.; Vagov, A. V.; Axt, V. M.; Perali, A.; Peeters, F. M.

    2012-09-01

    Quantum-size oscillations of the basic physical characteristics of a confined fermionic condensate are a well-known phenomenon. Its conventional understanding is based on the single-particle physics, whereby the oscillations follow variations in the single-particle density of states driven by the size quantization. Here we present a study of a cigar-shaped ultracold superfluid Fermi gas, which demonstrates an important many-body aspect of the quantum-size coherent effects, overlooked previously. The many-body physics is revealed here in the atypical crossover from the Bardeen-Cooper-Schrieffer (BCS) superfluid to the Bose-Einstein condensate (BEC) induced by the size quantization of the particle motion. The single-particle energy spectrum for the transverse dimensions is tightly bound, whereas for the longitudinal direction it resembles a quasi-free dispersion. This results in the formation of a series of single-particle subbands (shells) so that the aggregate fermionic condensate becomes a coherent mixture of subband condensates. Each time when the lower edge of a subband crosses the chemical potential, the BCS-BEC crossover is approached in this subband, and the aggregate condensate contains both BCS and BEC-like components.

  19. Molecular behavior of DNA in a cell-sized compartment coated by lipids

    CERN Document Server

    Hamada, T; Shimobayashi, S F; Ichikawa, M; Takagi, M

    2015-01-01

    The behavior of long DNA molecules in a cell-sized confined space was investigated. We prepared water-in-oil droplets covered by phospholipids, which mimic the inner space of a cell, following the encapsulation of DNA molecules with unfolded coil and folded globule conformations. Microscopic observation revealed that the adsorption of coiled DNA onto the membrane surface depended on the size of the vesicular space. Globular DNA showed a cell-size-dependent unfolding transition after adsorption on the membrane. Furthermore, when DNA interacted with a two-phase membrane surface, DNA selectively adsorbed on the membrane phase, such as an ordered or disordered phase, depending on its conformation. We discuss the mechanism of these trends by considering the free energy of DNA together with a polyamine in the solution. The free energy of our model was consistent with the present experimental data. The cooperative interaction of DNA and polyamines with a membrane surface leads to the size-dependent behavior of molec...

  20. Surface plasmon enhanced photoluminescence in amorphous silicon carbide films by adjusting Ag island film sizes

    International Nuclear Information System (INIS)

    Ag island films with different sizes are deposited on hydrogenated amorphous silicon carbide (α-SiC:H) films, and the influences of Ag island films on the optical properties of the α-SiC:H films are investigated. Atomic force microscope images show that Ag nanoislands are formed after Ag coating, and the size of the Ag islands increases with increasing Ag deposition time. The extinction spectra indicate that two resonance absorption peaks which correspond to out-of-plane and in-plane surface plasmon modes of the Ag island films are obtained, and the resonance peak shifts toward longer wavelength with increasing Ag island size. The photoluminescence (PL) enhancement or quenching depends on the size of Ag islands, and PL enhancement by 1.6 times on the main PL band is obtained when the sputtering time is 10 min. Analyses show that the influence of surface plasmons on the PL of α-SiC:H is determined by the competition between the scattering and absorption of Ag islands, and PL enhancement is obtained when scattering is the main interaction between the Ag islands and incident light. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. A study on size effect of carboxymethyl starch nanogel crosslinked by electron beam radiation

    Science.gov (United States)

    Binh, Doan; Pham Thi Thu Hong; Nguyen Ngoc Duy; Nguyen Thanh Duoc; Nguyen Nguyet Dieu

    2012-07-01

    The formation of carboxymethyl starch (CMS) nanogel with 50 nm less particle size was carried out through a radiation crosslinked process on the electron beam (EB) linear accelerator. Changes of intrinsic viscosities and weight averaged molecular weight in the CMS concentration, which ranged from 3 to 10 mg ml-1 in absorbed doses were investigated. There were some new peaks in the 1H NMR spectra of CMS nanogel compared with those of CMS polymer. These results were anticipated that the predominant intramolecular crosslinking of dilute CMS aqueous solution occurred while being exposed to a short intense pulse of ionizing radiation. Hydrodynamic radius (often called particle size, Rh) and distribution of particle size were measured by a dynamic light scattering technique. The radiation yield of intermolecular crosslinking of CMS solution was calculated from the expression of Gx (Charlesby, 1960; Jung-Chul, 2010). The influence of the "size effect" was demonstrated by testing culture of Lactobacillus bacteria on MRS agar culture medium containing CMS nanogel and polymer. Results showed that the number of Lactobacillus bacteria growing on nanogel containing culture medium is about 170 cfu/ml and on polymer containing culture medium is only 6 cfu/ml.

  2. Fluorescence quenching of fluoroquinolones by gold nanoparticles with different sizes and its analytical application

    Energy Technology Data Exchange (ETDEWEB)

    Amjadi, Mohammad, E-mail: amjadi@tabrizu.ac.ir; Farzampour, Leila

    2014-01-15

    The interaction of some fluoroquinolones including norfloxacin, ciprofloxacin, danofloxacin and ofloxacin with gold nanoparticles (AuNPs) of different sizes (8, 20 and 75 nm) was studied. In the studied systems, fluoroquinolones are noncovalently adsorbed onto the surface of AuNPs, which results in severe quenching of fluoroquinolones fluorescence possibly as a result of fluorescence resonance energy transfer. Stern–Volmer quenching constants were obtained and found to increase with an increase in the size of AuNPs. Moreover, the interactions between some thiols and fluoroquinolone-adsorbed AuNPs were investigated to explore the analytical applicability of the systems. It was found that upon the addition of thiols to fluoroquinolone-AuNPs systems the fluorescence of fluoroquinolones switches to “turn-on” due to the strong binding of thiols to AuNPs and removal of quinolines from NP surface. Under the optimum conditions, the fluorescence enhancement showed a linear relationship with the concentration of thiols, indicating the analytical usefulness of the system. -- Highlights: • Interaction of fluoroquinolones with AuNPs of different sizes was investigated. • The fluorescence of fluoroquinolones is efficiently quenched by AuNPs. • The fluorescence quenching efficiency increases by increasing NP size. • Fluoroquinolone-AuNPs systems can be used as sensitive turn-on sensors for thiols. • Danofloxacin-20-nm AuNPs system exhibits the highest sensitivity for thiols.

  3. Stabilization of microgrid with intermittent renewable energy sources by SMES with optimal coil size

    Energy Technology Data Exchange (ETDEWEB)

    Saejia, M., E-mail: samongkol@gmail.com [School of Electrical Engineering, Faculty of Engineering, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand); Ngamroo, I. [School of Electrical Engineering, Faculty of Engineering, King Mongkut' s Institute of Technology Ladkrabang, Bangkok 10520 (Thailand)

    2011-11-15

    A controller design of a superconducting magnetic energy storage unit is proposed. The structure of a power controller is the practical proportional-integral (PI). The PI parameters and coil size are tuned by a particle swarm optimization. The proposed method is able to effectively alleviate power fluctuations. It is well known that the superconducting coil is the vital part of a superconducting magnetic energy storage (SMES) unit. This paper deals with the power controller design of a SMES unit with an optimal coil size for stabilization of an isolated microgrid. The study microgrid consists of renewable energy sources with intermittent power outputs i.e., wind and photovoltaic. Since power generations from such renewable sources are unpredictable and variable, these result in power fluctuations in a microgrid. To stabilize power fluctuations, a SMES unit with a fast control of active and reactive power can be applied. The structure of a power controller is the practical proportional-integral (PI). Based on the minimization of the variance of power fluctuations from renewable sources as well as the initial stored energy of SMES, the optimal PI parameters and coil size are automatically and simultaneously tuned by a particle swarm optimization. Simulation studies show that the proposed SMES controller with an optimal coil size is able to effectively alleviate power fluctuations under various power patterns from intermittent renewable sources.

  4. Multimodal grain size distribution and high hardness in fine grained tungsten fabricated by spark plasma sintering

    International Nuclear Information System (INIS)

    Graphical abstract: Cross-sectional micrograph of spark plasma sintered tungsten with multimodal grain size distribution: (a) using focused ion beam (b) Bright field TEM image. Highlights: → High applied external pressure during SPS led to high density of the samples. → The consolidated samples by SPS had a multimodal size distribution. → Ultrafine grains were present within the samples sintered at low temperatures. → High Vickers hardness was obtained compared to commercial tungsten. → The consolidated samples were proved to be pure by chemical analysis. - Abstract: Preparation of fine grained, hard and ductile pure tungsten for future fusion reactor applications was tested using the bottom-up approach via powder consolidation by spark plasma sintering (SPS) at different temperature (1300-1800 deg. C) and pressure (90-266 MPa) conditions. Pure tungsten powders with an average particle size of about 1 μm were sintered to high density (about 94%) with almost no grain growth at a temperature below 1400 deg. C and an applied pressure up to 266 MPa. These samples had a multi-modal grain size distribution (resembling the size distribution of the initial powder) and a very high Vickers hardness (up to 530 kg/mm2). Above 1500 deg. C fast grain growth occurred and resulted in a drop in hardness. XRD on the surface of bulk samples showed a small amount of tungsten oxides; however, XPS and EDS indicated that these oxides were only surface contaminants and suggested a high purity for the bulk samples. The results demonstrate that SPS can lead to ultrafine and nanocrystalline tungsten if used to consolidate pure nano tungsten powders.

  5. Tailoring the size and distribution of Ag nanoparticles in silica glass by defects

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yitao, E-mail: yangyt@impcas.ac.cn [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, Chonghong; Song, Yin; Gou, Jie; Zhang, Liqing [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, Hengqing; Liu, Juan; Xian, Yongqiang [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ma, Yizhun [Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-02-15

    The composites embedded with metallic nanoparticles show large nonlinear optical susceptibility and strong surface plasmon resonance absorption, which enable potential application in opto-electronics. Ion implantation has been proven to be a powerful technique of synthesis of metallic nanoparticles due to its versatility and compatibility. However, the synthesis of nanoparticles by ion implantation inevitably leads to a broad size distribution due to Ostwald ripening process. The broad size distribution has a negative effect on improving the figure of merits for nonlinear optics. In this paper, we tried to introduce defects in silica glass to act as pre-nucleation centers to mediate the size and distribution of Ag nanoparticles. In experiment, the silica glass samples were pre-irradiated by 200 keV Ar ions to fluences of 0.8, 2.0 and 5.0 × 10{sup 16} ions/cm{sup 2}, and then 200 keV Ag ions were implanted into the pre-irradiated samples to fluence of 2.0 × 10{sup 16} ions/cm{sup 2}. UV–VIS results show that the absorbance intensity of Ag SPR peak initially increases and then decreases with pre-irradiation fluence, which implies the change in size and density of Ag nanoparticles in samples. TEM results verify that Ag nanoparticles in the sample pre-irradiated to the fluence of 0.8 × 10{sup 16} ions/cm{sup 2} grow bigger and distribute in a relatively narrow region comparing with that without pre-irradiation. With further increase of pre-irradiation fluence, the size of Ag nanoparticles shows a depth dependent distribution. A boundary can be clear seen at the depth of 110 nm, larger Ag nanoparticles disperse in region shallower than 110 nm, and smaller Ag nanoparticles disperse in the region deeper than 110 nm. The average size of Ag nanoparticles initially increases and then decreases with pre-irradiation fluence. Therefore, the introduction of defects by pre-irradiation could be an effective way to tailor the size and distribution of metallic nanoparticles in

  6. Object size effect on the contact potential difference measured by scanning Kelvin probe method

    OpenAIRE

    Polyakov, B.; Krutokhvostov, R.; Kuzmin, A.; Tamanis, E.; Muzikante, I.; Tale, I.

    2010-01-01

    Abstract Contact potential difference (CPD) was measured by macroscopic Kelvin probe instrument and scanning Kelvin probe microscope on Al, Ni and Pt on ITO substrates at ambient conditions. CPD values measured by scanning Kelvin probe microscope and macroscopic Kelvin probe are close within the error of about 10?30% for large studied objects, whereas scanning Kelvin probe microscope signal decreases, when the object size becomes smaller than 1.4 ?m. CPD and...

  7. Particle Size and Pore Structure Characterization of Silver Nanoparticles Prepared by Confined Arc Plasma

    Directory of Open Access Journals (Sweden)

    Mingru Zhou

    2009-01-01

    Full Text Available In the protecting inert gas, silver nanoparticles were successfully prepared by confined arc plasma method. The particle size, microstructure, and morphology of the particles by this process were characterized via X-ray powder diffraction (XRD, transmission electron microscopy (TEM and the corresponding selected area electron diffraction (SAED. The N2 absorption-desorption isotherms of the samples were measured by using the static volumetric absorption analyzer, the pore structure of the sample was calculated by Barrett-Joyner-Halenda (BJH academic model, and the specific surface area was calculated from Brunauer-Emmett-Teller (BET adsorption equation. The experiment results indicate that the crystal structure of the samples is face-centered cubic (FCC structure the same as the bulk materials, the particle size distribution ranging from 5 to 65 nm, with an average particle size about 26 nm obtained by TEM and confirmed by XRD and BET results. The specific surface area is 23.81 m2/g, pore volumes are 0.09 cm3/g, and average pore diameter is 18.7 nm.

  8. Polydisperse particle size characterization by ultrasonic attenuation spectroscopy in the micrometer range.

    Science.gov (United States)

    Richter, Andreas; Babick, Frank; Stintz, Michael

    2006-12-22

    The theoretical advantages of ultrasonic attenuation spectroscopy for particle size are currently not fully utilized. Especially in the region of larger particles, there is a lack of experimental confirmation of applicable models which may be used to infer particle sizes from measured attenuation spectra. With the present work, an attempt is made to supply experimental data, obtained with a commercially available ultrasonic attenuation spectrometer, and model calculations, which are based on the resonant scattering theory. It is shown that measured attenuation results for various combinations of disperse and continuous phase for both polydisperse emulsions and suspensions are reproducible by calculation. The approach is further examined for suspensions of porous particles. Here, the resonant scattering approach is combined with the Biot model for poroelasticity to obtain attenuation results with several fractions of titania aggregates, differing in particle size and pore diameter. The results indicate that the theory of resonant scattering is a valid approach if applied to particle size characterization in the large particle limit. PMID:16808945

  9. Experimental river delta size set by multiple floods and backwater hydrodynamics.

    Science.gov (United States)

    Ganti, Vamsi; Chadwick, Austin J; Hassenruck-Gudipati, Hima J; Fuller, Brian M; Lamb, Michael P

    2016-05-01

    River deltas worldwide are currently under threat of drowning and destruction by sea-level rise, subsidence, and oceanic storms, highlighting the need to quantify their growth processes. Deltas are built through construction of sediment lobes, and emerging theories suggest that the size of delta lobes scales with backwater hydrodynamics, but these ideas are difficult to test on natural deltas that evolve slowly. We show results of the first laboratory delta built through successive deposition of lobes that maintain a constant size. We show that the characteristic size of delta lobes emerges because of a preferential avulsion node-the location where the river course periodically and abruptly shifts-that remains fixed spatially relative to the prograding shoreline. The preferential avulsion node in our experiments is a consequence of multiple river floods and Froude-subcritical flows that produce persistent nonuniform flows and a peak in net channel deposition within the backwater zone of the coastal river. In contrast, experimental deltas without multiple floods produce flows with uniform velocities and delta lobes that lack a characteristic size. Results have broad applications to sustainable management of deltas and for decoding their stratigraphic record on Earth and Mars. PMID:27386534

  10. Rapid solidification behavior of nano-sized Sn droplets embedded in the Al matrix by nanocalorimetry

    International Nuclear Information System (INIS)

    Al-10Sn (wt.%) melt-spun ribbons with nano-sized Sn droplets (20–400 nm in diameter) embedded in the Al matrix and bulk Sn distributed at Al grain boundaries were prepared. Differential fast scanning calorimetry (DFSC) based on nanocalorimetry and thin film technique was successfully applied to investigate the rapid solidification behavior of the embedded nano-sized Sn droplets at cooling rates ranging from 103 to 104 K s−1. Two broad exothermic peaks were observed in the DFSC curves. They were ascribed to the solidification of nano-sized Sn droplets with various catalytic activity factors f(θ). The cooling rate dependence of undercooling of nano-sized Sn droplets has been studied experimentally. The two series of undercooling which correspond to the two exothermic peaks increase slightly with the increases of cooling rate. Furthermore, a theoretical description of the experimental DFSC curves based on classical heterogeneous nucleation theory is developed. It is performed advancing a previously developed approach by assuming a smooth dependence of the droplet mass fraction on contact angle, m(θ), with a double Gaussian distribution during the nucleation process. This modified theoretical model is believed to be relevant also for other related rapid solidification processes. (paper)

  11. Experimental river delta size set by multiple floods and backwater hydrodynamics

    Science.gov (United States)

    Ganti, Vamsi; Chadwick, Austin J.; Hassenruck-Gudipati, Hima J.; Fuller, Brian M.; Lamb, Michael P.

    2016-01-01

    River deltas worldwide are currently under threat of drowning and destruction by sea-level rise, subsidence, and oceanic storms, highlighting the need to quantify their growth processes. Deltas are built through construction of sediment lobes, and emerging theories suggest that the size of delta lobes scales with backwater hydrodynamics, but these ideas are difficult to test on natural deltas that evolve slowly. We show results of the first laboratory delta built through successive deposition of lobes that maintain a constant size. We show that the characteristic size of delta lobes emerges because of a preferential avulsion node—the location where the river course periodically and abruptly shifts—that remains fixed spatially relative to the prograding shoreline. The preferential avulsion node in our experiments is a consequence of multiple river floods and Froude-subcritical flows that produce persistent nonuniform flows and a peak in net channel deposition within the backwater zone of the coastal river. In contrast, experimental deltas without multiple floods produce flows with uniform velocities and delta lobes that lack a characteristic size. Results have broad applications to sustainable management of deltas and for decoding their stratigraphic record on Earth and Mars. PMID:27386534

  12. Size of bacterial ice-nucleation sites measured in situ by radiation inactivation analysis

    International Nuclear Information System (INIS)

    Four bacterial species are known to catalyze ice formation at temperatures just below 00C. To better understand the relationship between the molecular structure of bacterial ice-nucleation site(s) and the quantitative and qualitative features of the ice-nucleation-active phenotype, the authors determined by γ-radiation analysis the in situ size of ice-nucleation sites in strains of Pseudomonas syringae and Erwinia herbicola and in Escherichia coli HB101 carrying the plasmid pICE1.1. Lyophilized cells of each bacterial strain were irradiated with a flux of γ radiation from 0 to 10.2 Mrad. Differential concentrations of active ice nuclei decreased as a first-order function of radiation dose in all strains as temperature was decreased from -20C to -140C in 10C intervals. Sizes of ice nuclei were calculated from the +-radiation flux at which 37% of initial ice nuclei active within each 10C temperature interval remained. The minimum mass of a functional ice nucleus was about 150 kDa for all strains. The size of ice nuclei increased logarithmically with increasing temperature from -120CC to -20C, where the estimated nucleant mass was 19,000 kDa. The ice nucleant in these three bacterial species may represent an oligomeric structure, composed at least in part of an ice gene product that can self-associate to assume many possible sizes

  13. Molecular size of bovine lipoprotein lipase as determined by radiation inactivation

    International Nuclear Information System (INIS)

    The authors have determined the size of the functional unit of bovine lipoprotein lipase by radiation inactivation. This was done in five different situations: 1) in a buffer with high salt concentration. In this situation the enzyme is relatively soluble and stable. 2) For an enzyme-heparin complex. This may reflect the physiological state of the enzyme at the vascular endothelium, where it is believed to be bound to a heparin-like molecule. 3) In the presence of lipid substrate and 4) with lipid substrate and activator protein. Here most of the enzyme is adsorbed to the substrate droplets. 5) For an enzyme-detergent complex; another model for enzyme-lipid interaction. In all five situations the enzyme activity decayed as an exponential function of radiation dose, and the target sizes were similar. The target size did not vary with the concentration of lipase protein. The combined data for bovine lipoprotein lipase yield a functional size of 72 kDa which is close to that expected for a dimer, 77 kDa

  14. Measurement of aerosol size distribution by impaction and sedimentation An experimental study and data reduction

    International Nuclear Information System (INIS)

    This study concerns essentially solid aerosols produced by combustion and more particulary the aerosol liberated by a sodium fire taken into account in safety studies related to sodium cooled nuclear reactors. The accurate determination of the aerosol size distribution depends on the selection device use. An experimental study of the parameters affecting the solid aerosol collection efficiency was made with the Andersen Mark II cascade impactor (blow off and bounce, electrical charge of particles, wall-loss). A sedimentation chamber was built and calibrated for the range between 4 and 10 μm. The second part describes a comparative study of different data reduction methods for the impactor and a new method for setting up the aerosol size distribution with data obtained by the sedimentation chamber

  15. Finite size effects in hadron-quark phase transition by the Dyson-Schwinger method

    Science.gov (United States)

    Yasutake, N.; Chen, H.; Maruyama, T.; Tatsumi, T.

    2016-01-01

    We study the hadron-quark phase transition, taking into account the finite-size effects for neutron star matter. For the hadron phase, we adopt a realistic equation of state within the framework of the Brueckner-Hartree-Fock theory. For the quark phase, we apply the Dyson-Schwinger method. The properties of the mixed phase are clarified by considering the finite-size effects. We find that, if the surface tension is strong enough, the equation of state becomes to be close the one with the Maxwell condition, though we properly adopt the Gibbs conditions. This result is qualitatively the same with the one by the use of the simple bag model. We also find that the mass-radius relation by the EoS is consistent with the observations of massive neutron stars.

  16. Nano-meter beam size monitor by laser-Compton scattering

    International Nuclear Information System (INIS)

    A spot size measurement system at nano-meter range using Compton scattering of laser beam has been proposed for a reliable diagnostic instrument of electron beam at interaction point in e+e- linear colliders. The high energy electron beam is injected into a standing wave of laser light, and generates high energy γ-rays by Compton scattering. We measure spatial modulation of γ-ray flux by scanning the electron beam trajectory along laser axis. From the modulation depth, the transverse electron beam size is determined. A system based on this scheme using Nd:YAG-laser of 1064 nm wavelength is under construction, and will be installed in FFTB beam line in SLAC, and tested with a fine beam of 1 μm by 60 nm in transverse dimensions. (author)

  17. Notes on representing grain size distributions obtained by electron backscatter diffraction

    International Nuclear Information System (INIS)

    Grain size distributions measured by electron backscatter diffraction are commonly represented by histograms using either number or area fraction definitions. It is shown here that they should be presented in forms of density distribution functions for direct quantitative comparisons between different measurements. Here we make an interpretation of the frequently seen parabolic tales of the area distributions of bimodal grain structures and a transformation formula between the two distributions are given in this paper. - Highlights: • Grain size distributions are represented by density functions. • The parabolic tales corresponds to equal number of grains in a bin of the histogram. • A simple transformation formula is given to number and area weighed distributions. • The particularities of uniform and lognormal distributions are examined

  18. Controlling the Fluctuations of Wind Power By SMES Using Optimized Coil Size

    Directory of Open Access Journals (Sweden)

    Ankur Saini

    2014-09-01

    Full Text Available The hybrid power system that solely depends on the intermittent renewable energy sources will generate a fluctuating output power that leads to damage to the machines that operates on a stable supply. Therefore, an energy storage system Super Conducting Magnetic Energy Storage (SMES is introduced with function to reduce the output power fluctuation problems. SMES systems are efficient devices of storing large electrical energy but they are quite costly. Thus this paper suggests an Optimization method of optimizing the controller parameters, SMES current and Coil Size of the SMES thereby controls the power fluctuation. In controller PI controller is used to control Active and Reactive power of the Tie-line. Based on the minimization of variance active and reactive power fluctuation is reduced. The controller parameters, Coil Size and Initial SMES current are tuned by Particle Swarm Optimization and compared the results by Genetic Algorithm. This optimization and Controller model is realized by using MATLAB.

  19. Control of nanoparticle size, reactivity and magnetic properties during the bioproduction of magnetite by Geobacter sulfurreducens

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, J. M.; Telling, N. D.; Coker, V. S.; Pattrick, R. A. D.; Laan, G. van der; Arenholz, E.; Tuna, F.; Lloyd, J. R.

    2011-08-02

    The bioproduction of nano-scale magnetite by Fe(III)-reducing bacteria offers a potentially tunable, environmentally benign route to magnetic nanoparticle synthesis. Here, we demonstrate that it is possible to control the size of magnetite nanoparticles produced by Geobacter sulfurreducens, by adjusting the total biomass introduced at the start of the process. The particles have a narrow size distribution and can be controlled within the range of 10-50 nm. X-ray diffraction analysis indicates that controlled production of a number of different biominerals is possible via this method including goethite, magnetite and siderite, but their formation is strongly dependent upon the rate of Fe(III) reduction and total concentration and rate of Fe(II) produced by the bacteria during the reduction process. Relative cation distributions within the structure of the nanoparticles has been investigated by X-ray magnetic circular dichroism and indicates the presence of a highly reduced surface layer which is not observed when magnetite is produced through abiotic methods. The enhanced Fe(II)-rich surface, combined with small particle size, has important environmental applications such as in the reductive bioremediation of organics, radionuclides and metals. In the case of Cr(VI), as a model high-valence toxic metal, optimised biogenic magnetite is able to reduce and sequester the toxic hexavalent chromium very efficiently in the less harmful trivalent form.

  20. Body and major organ sizes of young mature microminipigs determined by computed tomography.

    Science.gov (United States)

    Takasu, Masaki; Tsuji, Eriko; Imaeda, Noriaki; Matsubara, Tatsuya; Maeda, Masami; Ito, Yusuke; Shibata, Sanae; Ando, Asako; Nishii, Naohito; Yamazoe, Kazuaki; Kitagawa, Hitoshi

    2015-01-01

    To understand the anatomical characteristics of microminipigs, one of the smallest miniature pigs, as a large animal model, we measured the body and organ sizes of four-, five-, six-, and seven-month-old microminipigs (n = 4, females) using computed tomography. In addition, the results were compared with those of young mature beagles (10 months old, two males and three females), which have been widely used as a large animal model. The microminipigs at 4-6 months of age were much smaller than the beagles. However, when the microminipigs reached seven months of age, their overall size was similar to that of the beagles. The thoracic cavity volume of the seven-month-old microminipigs was less than half that of the beagles, and the cavity was largely filled by the heart. The liver size of the seven-month-old microminipigs was approximately half of that of the beagles. Moreover, the spleen of the seven-month-old microminipigs was different in morphology, but not different in size from that of the beagles. In addition, although their volumes were the same, the kidneys of the seven-month-old microminipigs, unlike those of the beagles, were flattened in shape. Collectively, the major abdominal organs of the seven-month-old microminipigs were either the same size or smaller than those of the beagles, but the abdominal cavity volume of the seven-month-old microminipigs was larger than that of the beagles. Thus, the abdominal cavity of microminipigs is assumed to be filled with the gastrointestinal tract. The anatomical characteristics of the young mature microminipigs revealed in our study suggest that microminipigs could have great potential as a large animal model for biomedical research. PMID:25341543

  1. Molecular sizes of lichen ice nucleation sites determined by gamma radiation inactivation analysis

    International Nuclear Information System (INIS)

    It has previously been shown that some species of lichen fungi contain proteinaceous ice nuclei which are active at temperatures as warm as −2 °C. This experiment was undertaken to determine the molecular sizes of ice nuclei in the lichen fungus Rhizoplaca chrysoleuca and to compare them to bacterial ice nuclei from Pseudomonas syringae. Gamma radiation inactivation analysis was used to determine molecular weights. Radiation inactivation analysis is based on target theory, which states that the likelihood of a molecule being inactivated by gamma rays increases as its size increases. Three different sources of ice nuclei from the lichen R. chrysoleuca were tested: field-collected lichens, extract of lichen fungus, and a pure culture of the fungus R. chrysoleuca. P. syringae strain Cit7 was used as a source of bacterial ice nuclei. Samples were lyophilized, irradiated with gamma doses ranging from 0 to 10.4 Mrads, and then tested for ice nucleation activity using a droplet-freezing assay. Data for all four types of samples were in rough agreement; sizes of nucleation sites increased logarithmically with increasing temperatures of ice nucleation activity. Molecular weights of nucleation sites active between −3 and −4 °C from the bacteria and from the field-collected lichens were approximately 1.0 × 106 Da. Nuclei from the lichen fungus and in the lichen extract appeared to be slightly smaller but followed the same log-normal pattern with temperature of ice nucleation activity. The data for both the bacterial and lichen ice nuclei are in agreement with ice nucleation theory which states that the size of ice nucleation sites increases logarithmically as the temperature of nucleation increases linearly. This suggests that although some differences exist between bacterial and lichen ice nucleation sites, their molecular sizes are quite similar

  2. Evaluation of submicron sized drug particles of salbutamol sulphate by gamma scintigraphy in bronchopulmonary disorders

    International Nuclear Information System (INIS)

    Full text: Objective of the present study was to compare the lung deposition pattern of micronized and submicronized salbutamol sulphate nebulization using inhalation therapy for alveolar deposition (ITAD) concept. Materials and Methods: Salbutamol sulphate was radiolabeled with 99mTc. All the labeling experiments were done at neutral pH. To the labeled drug solution saline was added to make the final concentration 2.5 mg/ml. For the deposition of micron sized particles conventional nebulization method was used while in case of submicron particles, ITAD concept was used. In ITAD concept the final volume was made by the addition of ethanolic saline and the particles generated by compressor were passed through large spacers before inhalation by patients. Passing the particles through the large spacer will cause the segregation of particles on the basis of size and mass. Particles which are heavy and with larger diameter will settle down at the bottom of spacer while the lighter and smaller sized particles will cross the spacer and will be available for the inhalation. Result: Scintigraphy images show better lung deposition in case of ITAD concept as compared to traditional/conventional method. Images also insure that the drug gets deposited in the peripheral region by the ITAD concept. Conclusion: It has been concluded that ITAD concept is a better alternative to the conventional nebulization method for the treatment of alveolar pathologies

  3. Changes in metal nanoparticle shape and size induced by swift heavy-ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ridgway, M.C. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra (Australia)], E-mail: mark.ridgway@anu.edu.au; Kluth, P.; Giulian, R.; Sprouster, D.J.; Araujo, L.L.; Schnohr, C.S.; Llewellyn, D.J. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra (Australia); Byrne, A.P. [Department of Physics, Research School of Physics and Engineering, Australian National University, Canberra (Australia); Foran, G.J. [Australian Nuclear Science and Technology Organisation, Menai (Australia); Cookson, D.J. [Australian Synchrotron, Clayton (Australia)

    2009-03-15

    Changes in the shape and size of Co, Pt and Au nanoparticles induced by swift heavy-ion irradiation (SHII) have been characterized using a combination of transmission electron microscopy, small-angle X-ray scattering and X-ray absorption near-edge structure. Elemental nanoparticles of diameters 2-15 nm were first formed in amorphous SiO{sub 2} by ion implantation and thermal annealing and then irradiated at room temperature with 27-185 MeV Au ions as a function of fluence. Spherical nanoparticles below a minimum diameter (4-7 nm) remained spherical under SHII but progressively decreased in size as a result of dissolution into the SiO{sub 2} matrix. Spherical nanoparticles above the minimum diameter threshold were transformed to elongated rods aligned with the ion beamdirection. The nanorod width saturated at an electronic energy deposition dependent value, progressively increasing from 4-6 to 7-10 nm (at 5-18 keV/nm, respectively) while the nanorod length exhibited a broad distribution consistent with that of the unirradiated spherical nanoparticles. The threshold diameter for spherical nanoparticle elongation was comparable to the saturation value of nanorod width. We correlate this saturation value with the diameter of the molten track induced in amorphous SiO{sub 2} by SHII. In summary, changes in nanoparticle shape and size are governed to a large extent by the ion irradiation parameters.

  4. Fabrication of Pt nanowires with a diffraction-unlimited feature size by high-threshold lithography

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li, E-mail: lil@cust.edu.cn, E-mail: wangz@cust.edu.cn, E-mail: kq-peng@bnu.edu.cn; Zhang, Ziang; Yu, Miao; Song, Zhengxun; Weng, Zhankun [International Research Centre for Nano Handling and Manufacturing of China (CNM) and Joint Research Centre for Computer-Controlled Nanomanufacturing (JR3CN), Changchun University of Science and Technology, Changchun 130022 (China); Wang, Zuobin, E-mail: lil@cust.edu.cn, E-mail: wangz@cust.edu.cn, E-mail: kq-peng@bnu.edu.cn; Li, Wenjun; Wang, Dapeng; Zhao, Le [International Research Centre for Nano Handling and Manufacturing of China (CNM) and Joint Research Centre for Computer-Controlled Nanomanufacturing (JR3CN), Changchun University of Science and Technology, Changchun 130022 (China); Joint Research Centre for Computer-Controlled Nanomanufacturing (JR3CN), University of Bedfordshire, Luton LU1 3JU (United Kingdom); Peng, Kuiqing, E-mail: lil@cust.edu.cn, E-mail: wangz@cust.edu.cn, E-mail: kq-peng@bnu.edu.cn [Department of Physics and Beijing Key Laboratory of Energy Conversion and Storage Materials, Beijing Normal University, Beijing 100875 (China)

    2015-09-28

    Although the nanoscale world can already be observed at a diffraction-unlimited resolution using far-field optical microscopy, to make the step from microscopy to lithography still requires a suitable photoresist material system. In this letter, we consider the threshold to be a region with a width characterized by the extreme feature size obtained using a Gaussian beam spot. By narrowing such a region through improvement of the threshold sensitization to intensity in a high-threshold material system, the minimal feature size becomes smaller. By using platinum as the negative photoresist, we demonstrate that high-threshold lithography can be used to fabricate nanowire arrays with a scalable resolution along the axial direction of the linewidth from the micro- to the nanoscale using a nanosecond-pulsed laser source with a wavelength λ{sub 0} = 1064 nm. The minimal feature size is only several nanometers (sub λ{sub 0}/100). Compared with conventional polymer resist lithography, the advantages of high-threshold lithography are sharper pinpoints of laser intensity triggering the threshold response and also higher robustness allowing for large area exposure by a less-expensive nanosecond-pulsed laser.

  5. Speciation of metals in soil extracts by size exclusion chromatography/inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Metal ion speciation influences the mobility of metals in the environment and their bioavailability. Dissolved humic substances (HS) and low molecular weight organic acids greatly influence the speciation of metals in soil and other natural environment. This study was conducted to identify HS bound metal in citric acid extracts from soil by size exclusion chromatography/inductively coupled plasma mass spectrometry (SEC/ICP-MS). The size exclusion column, which has optimal separation range from 3000-7000, was used. Absorption was monitored at 280 nm using an UV/VIS absorption detector. The eluate from the detector was directly introduced to the ICP-MS through a nebulizer. The size exclusion chromatography could separate HS and citric acid used for extraction. This was confirmed by the results obtained using a multi-channel diode array detector. HS was evidenced by broad absorption from UV to VIS range while organic acid was by narrow UV absorption. Analysis showed that most of iron was bound to HS, while part of aluminium was bound HS. Other metals were not bound to HS and some transitional metals except manganese made complex with citric acid. Most of silicon was not bound to HS and probably existed in the form of silicic acid. (author)

  6. Fabrication of Pt nanowires with a diffraction-unlimited feature size by high-threshold lithography

    International Nuclear Information System (INIS)

    Although the nanoscale world can already be observed at a diffraction-unlimited resolution using far-field optical microscopy, to make the step from microscopy to lithography still requires a suitable photoresist material system. In this letter, we consider the threshold to be a region with a width characterized by the extreme feature size obtained using a Gaussian beam spot. By narrowing such a region through improvement of the threshold sensitization to intensity in a high-threshold material system, the minimal feature size becomes smaller. By using platinum as the negative photoresist, we demonstrate that high-threshold lithography can be used to fabricate nanowire arrays with a scalable resolution along the axial direction of the linewidth from the micro- to the nanoscale using a nanosecond-pulsed laser source with a wavelength λ0 = 1064 nm. The minimal feature size is only several nanometers (sub λ0/100). Compared with conventional polymer resist lithography, the advantages of high-threshold lithography are sharper pinpoints of laser intensity triggering the threshold response and also higher robustness allowing for large area exposure by a less-expensive nanosecond-pulsed laser

  7. A radiologic study by CT scan of pineal size in cancer patients

    International Nuclear Information System (INIS)

    Alterations in size of the pineal body and melatonin secretion have been observed in cancer patients. The present study was carried out to evaluate pineal dimension in a group of cancer patients and their relation to melatonin blood levels. The study included 70 oncologic patients. As controls, 41 patients with acute or chronic disease other than cancer entered the study. Melatonin serum levels were measured by radioimmunoassay on venous blood samples collected at 9:00 a.m. Pineal size was determined by brain CT scan, by considering the product of the two longest perpendicular diameters, multiplied by the thickness of the stratum. The volume of the pineal body was found to be enlarged in 12/70 (17%) cancer patients, and its mean value was significantly higher than that observed in controls. Melatonin levels were also significantly higher in oncologic patients than in controls. However, there was no correlation between melatonin levels and pineal size in cancer patients. Finally, cancer patients did not show a higher degree of pineal calcifications than controls. The clinical significance of pineal enlargement in cancer patients remains to be understood

  8. Predicting size effect on diffusion-limited current density of oxygen reduction by copper wire

    Institute of Scientific and Technical Information of China (English)

    LU Yonghong; XU Haibo; WANG Jia; ZHONG Lian

    2011-01-01

    The size effect of copper wire radius (0.04鈥?.82 mm) on the diffusion-limited current density of an oxygen reduction reaction in stagnant simulated seawater (naturally aerated 0.5 mol/L NaCl) is investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) and compared with the results obtained in 0.5 mol/L H2SO4. In the oxygen diffusion-limited range, size effect is found to occur independent of electrolytes, which is attributed to non-linear diffusion. Additionally, to satisfy application in a marine setting, an empirical equation correlating oxygen diffusion-limited current density to copper wire radius is proposed by fitting experimental data.

  9. Differentiation between heterotrophic and photosynthetic plankton by size fractionation, glucose uptake, ATP and chlorophyll content

    International Nuclear Information System (INIS)

    By means of a technique which included 3H-D-glucose uptake, ATP and chlorophyll analyses in different size fractions of lake water microorganisms, the bacterial and the phytoplankton biomasses were estimated from four eutrophic lakes. Short term glucose uptake experiments and chlorophyll analyses in lake water used as indicators of the bacteria and the phytoplankton present in the different size fractions, whereas ATP measurements were used to quantify their respective biomasses. The bacteria comprised between 3 and 18% of total biomass (phytoplankton + bacteria) and between 50 and 90% of the bacteria were free-living. The numbers of bacteria calculated from the bacterial ATP content were 20 to 50% higher than the numbers estimated by direct counting. (author)

  10. Judging a book by its cover: the unconscious influence of pupil size on consumer choice.

    Science.gov (United States)

    Wiseman, Richard; Watt, Caroline

    2010-01-01

    Past research suggests that men perceive women with large pupils as especially attractive. We employed an innovative methodology to examine whether this effect influences consumer decision-making. A popular psychology book was published with two slightly different front covers. Both covers contained the same photograph of a woman; however, the woman's pupils on one cover were digitally enlarged. Readers indicated whether they were male or female, and whether they possessed the cover with small or large pupils. A significantly greater percentage of men than women had chosen the cover with the large pupils. None of the participants who attempted to guess the nature of the experiment was correct, suggesting that the influence exerted by pupil size was unconscious. These findings provide further support for the notion that people's judgments are unconsciously swayed by pupil size, and demonstrate that this effect operates in a real world setting. PMID:21180363

  11. Preparation of YAG:Nd nano-sized powder by co-precipitation method

    International Nuclear Information System (INIS)

    Nd3+ doped yttrium aluminum garnet Y3Al5O12 (YAG) nano-sized powders were prepared by a co-precipitation method using hydroxypropyl cellulose (HPC) as dispersant. The formation process and structure of the as-prepared sample were investigated by means of TG-DTA, XRD, IR, and TEM. It has been found that the YAG powders were amorphous up to 700 deg. C and transformed into pure phase YAG crystallite at 900 deg. C for 2 h, because of the uniformly distribution of Al and Y elements. The size of YAG powder is about 30 nm in diameter and mono-disperse in the presence of HPC. Optical absorption and emission spectra of nano-crystallites versus Nd3+ concentration and sintering temperature were also studied

  12. Single-shot measurement of soot aggregate sizes by wide-angle light scattering (WALS)

    Science.gov (United States)

    Oltmann, H.; Reimann, J.; Will, S.

    2012-01-01

    The wide-angle light scattering (WALS) approach has been utilized for the measurement of soot aggregate sizes (radii of gyration) in flames on a single-shot basis. Key elements are a pulsed laser and an ellipsoidal mirror, which images the light scattered within a plane onto an intensified CCD camera, thus allowing for an instantaneous acquisition of a full scattering diagram with high resolution. Results for a laminar premixed flame exhibit good agreement with averaged data and demonstrate the feasibility of the method. The applicability of the technique to unsteady combustion processes is demonstrated by measuring aggregate sizes in a weakly turbulent jet-diffusion flame. In both cases light scattering results are verified by data obtained from electron microscopy analysis of sampled soot.

  13. Speciation of fission products in raw cow milk by high-performance size exclusion radiochromatography

    International Nuclear Information System (INIS)

    Speciation of fission products (90Sr, 99Tc, 137Cs and 152Eu) in raw cow milk was studied using the high-performance size exclusion radiochromatography (HP-SERC) by Biosep-SEC-SR column (Phenomenex, USA). The separation fraction were identified by a UV detector (280 nm) and a scintillation radiodetector. The mobile phase was Jennes-Koops buffer that simulated milk serum. Radiocesium was present only in non-protein fractions. The non-protein fractions complexed 17% of technetium and 57% of strontium. About 32% of strontium and 24% of europium were bound on the high molecular weight proteins (micellar casein). Low molecular weight proteins bound about 11% of strontium and 76% of europium. Non-size effects play a dominant role at HPSERC speciation of technetium, 83% of which follow the lightest fractions of milk. (author)

  14. Induced Effects on Red Imported Fire Ant (Hymenoptera: Formicidae) Forager Size Ratios by Pseudacteon spp. (Diptera: Phoridae): Implications on Bait Size Selection.

    Science.gov (United States)

    Reed, J J; Puckett, R T; Gold, R E

    2015-10-01

    Red imported fire ants, Solenopsis invicta Buren, are adversely affected by phorid flies in the genus Pseudacteon by instigating defensive behaviors in their hosts, and in turn reducing the efficiency of S. invicta foraging. Multiple Pseudacteon species have been released in Texas, and research has been focused on the establishment and spread of these introduced biological control agents. Field experiments were conducted to determine bait particle size selection of S. invicta when exposed to phorid populations. Four different particle sizes of two candidate baits were offered to foragers (one provided by a pesticide manufacturer, and a laboratory-created bait). Foragers selectively were attracted to, and removed more 1-1.4-mm particles than any other bait size. The industry-provided bait is primarily made of particles in the 1.4-2.0 mm size, larger than what was selected by the ants in this study. While there was a preference for foragers to be attracted to and rest on the industry-provided blank bait, S. invicta removed more of the laboratory-created bait from the test vials. There was an abundance of workers with head widths ranging from 0.5-0.75 mm collected from baits. This was dissimilar from a previous study wherein phorid flies were not active and in which large workers were collected in higher abundance at the site. This implies that phorid fly activity caused a shift for red imported fire ant colonies to have fewer large foragers. PMID:26314020

  15. Quantitative evaluation of size selective precipitation of Mn-doped ZnS quantum dots by size distributions calculated from UV/Vis absorbance spectra

    International Nuclear Information System (INIS)

    We demonstrate the quantitative evaluation of the sharp classification of manganese-doped zinc sulfide (ZnS:Mn) quantum dots by size selective precipitation. The particles were characterized by the direct conversion of absorbance spectra to particle size distributions (PSDs) and high-resolution transmission electron micrographs (HRTEM). Gradual addition of a poor solvent (2-propanol) to the aqueous colloid led to the flocculation of larger particles. Though the starting suspension after synthesis had an already narrow PSD between 1.5 and 3.2 nm, different particle size fractions were subsequently isolated by the careful adjustment of the good solvent/poor solvent ratio. Moreover, due to the fact that for the analysis of the classification results the size distributions were available, an in-depth understanding of the quality of the distinct classification steps could be achieved. From the PSDs of the feed, as well as the coarse and the fine fractions with their corresponding yields determined after each classification step, an optimum after the first addition of poor solvent was identified with a maximal separation sharpness κ as high as 0.75. Only by the quantitative evaluation of classification results leading to an in-depth understanding of the relevant driving forces, a future transfer of this lab scale post-processing to larger quantities will be possible.

  16. Preferential feeding by the crab Necora puber on differing sizes of the intertidal limpet Patella vulgata

    OpenAIRE

    A.C. Silva; Hawkins, S. J.; Clarke, K.R.; Boaventura, D.M.; Thompson, R C

    2010-01-01

    The crab Necora puber L. is a common predator of limpets, the major grazer on rocky shores in Northern Europe. Information on interactions between crabs and their limpet prey is limited, extending mainly to limpet defensive and predator offensive tactics, while the importance of prey size on the outcome of such interactions remains largely unknown. Here, a laboratory approach was used to test for preference in feeding habits. Predation by N. puber with cheliped height 3 to 27 mm (carapace wid...

  17. Determination of microbial genome sizes by two-dimensional denaturing gradient gel electrophoresis.

    OpenAIRE

    Poddar, S K; Maniloff, J

    1989-01-01

    In two-dimensional denaturing gradient gel electrophoresis, DNA is digested with a restriction endonuclease and the resulting DNA fragments are separated as a function of size by conventional agarose gel electrophoresis. Following this first dimension electrophoresis, the fragment distribution is placed at the top of a denaturing gradient slab gel and electrophoresis is carried out parallel to the gradient direction. This second dimension separation is a complex function of the base sequence ...

  18. Experimental river delta size set by multiple floods and backwater hydrodynamics

    OpenAIRE

    Ganti, Vamsi; Chadwick, Austin J.; Hassenruck-Gudipati, Hima J.; Fuller, Brian M.; Lamb, Michael P.

    2016-01-01

    River deltas worldwide are currently under threat of drowning and destruction by sea-level rise, subsidence, and oceanic storms, highlighting the need to quantify their growth processes. Deltas are built through construction of sediment lobes, and emerging theories suggest that the size of delta lobes scales with backwater hydrodynamics, but these ideas are difficult to test on natural deltas that evolve slowly. We show results of the first laboratory delta built through successive deposition...

  19. Maximum leaf conductance driven by CO2 effects on stomatal size and density over geologic time

    OpenAIRE

    Franks, Peter J.; Beerling, David J.

    2009-01-01

    Stomatal pores are microscopic structures on the epidermis of leaves formed by 2 specialized guard cells that control the exchange of water vapor and CO2 between plants and the atmosphere. Stomatal size (S) and density (D) determine maximum leaf diffusive (stomatal) conductance of CO2 (gcmax) to sites of assimilation. Although large variations in D observed in the fossil record have been correlated with atmospheric CO2, the crucial significance of similarly large variations in S has been over...

  20. The Changing Size Distribution of U.S. Trade Unions and Its Description by Pareto's Distribution

    OpenAIRE

    John Pencavel

    2013-01-01

    The size distribution of trade unions in the United States and changes in this distribution are documented. Because the most profound changes are taking place among very large unions, these are subject to special analysis by invoking Pareto’s distribution. This represents a new application of this distribution. Extensions to trade union wealth and to Britain are broached. The role of the public sector in these changes receives particular attention. A simple model helps account both for the lo...

  1. Analytical Approach for Loss Minimization in Distribution Systems by Optimum Placement and Sizing of Distributed Generation

    Directory of Open Access Journals (Sweden)

    Bakshi Surbhi

    2016-01-01

    Full Text Available Distributed Generation has drawn the attention of industrialists and researchers for quite a time now due to the advantages it brings loads. In addition to cost-effective and environmentally friendly, but also brings higher reliability coefficient power system. The DG unit is placed close to the load, rather than increasing the capacity of main generator. This methodology brings many benefits, but has to address some of the challenges. The main is to find the optimal location and size of DG units between them. The purpose of this paper is distributed generation by adding an additional means to reduce losses on the line. This paper attempts to optimize the technology to solve the problem of optimal location and size through the development of multi-objective particle swarm. The problem has been reduced to a mathematical optimization problem by developing a fitness function considering losses and voltage distribution line. Fitness function by using the optimal value of the size and location of this algorithm was found to be minimized. IEEE-14 bus system is being considered, in order to test the proposed algorithm and the results show improved performance in terms of accuracy and convergence rate.

  2. Determination of cosmic bodies size-velocity distribution by observation of current impacts on Mars

    Science.gov (United States)

    Nemchinov, I. V.; Perelomova, A. A.; Shuvalov, V. V.

    1993-01-01

    Collisions of cosmic bodies with terrestrial planets involve many physical processes such as deceleration and ablation during their flight through an atmosphere, the impact at a surface accompanied by cratering, melting and evaporation of surface material, generation of shock waves, etc. If body velocity is high enough then a thermal radiation is very important. All these processes on Mars proceed differently than on the other planets because of the low density of its atmosphere. In particular, this leads to the fact that smaller bodies of sizes of the order of 0.1-10 m strike the planet surface without being decelerated and perform some effects which may be detected by equipment placed on a board of artificial satellites, by a network of stations at the surface of Mars and even from the Earth. These observations can be used to determine size-velocity distribution of such bodies in the Solar System. Numerical simulation of the impacts at the surface of Mars have been carried out using two-dimensional gas dynamic code with detailed consideration of the thermal radiative transfer. This work is an extension of our previous paper. We have expanded a range of projectile sizes up to r sub 0 = 100 m. For such a large-scale body, the initial stage of the impact, involving crate ring and ejection of surface material, is very important. Thus, these effects have been taken into account.

  3. Permanent alterations in muscarinic receptors and pupil size produced by chronic atropinization in kittens

    International Nuclear Information System (INIS)

    Chronic mydriasis was induced in six kittens (four monocular, two binocular) and two adult cats (both monocular) by the daily topical application of atropine. Both the kittens and the adult cats were atropinized for a 13-week period with the treatment regimen beginning at the time of eye opening for the kittens. Pupil size measurements, obtained 1 year after the atropinization were discontinued, revealed that, although the pupils of the adult cats were normal, the pupils of the kittens' treated eyes were consistently smaller than pupils in control eyes. The status of the muscarinic receptors in the kittens' irides was investigated using 3H-QNB binding assays. In comparison with iris muscle homogenates from the control eyes, those from the treated eyes demonstrated an eightfold increase in the number of receptor binding sites. The results indicate that pupil size can be altered permanently by chronic mydriasis initiated early in the life of a kitten and that the permanent change in pupil size may result, in part, from a type of permanent supersensitivity response in the muscle following chronic blockade of muscarinic transmission by atropine

  4. The shape and size distribution of crystalline nanoparticles prepared by acid hydrolysis of native cellulose.

    Science.gov (United States)

    Elazzouzi-Hafraoui, Samira; Nishiyama, Yoshiharu; Putaux, Jean-Luc; Heux, Laurent; Dubreuil, Frédéric; Rochas, Cyrille

    2008-01-01

    The shape and size distribution of crystalline nanoparticles resulting from the sulfuric acid hydrolysis of cellulose from cotton, Avicel, and tunicate were investigated using transmission electron microscopy (TEM) and atomic force microscopy (AFM) as well as small- and wide-angle X-ray scattering (SAXS and WAXS). Images of negatively stained and cryo-TEM specimens showed that the majority of cellulose particles were flat objects constituted by elementary crystallites whose lateral adhesion was resistant against hydrolysis and sonication treatments. Moreover, tunicin whiskers were described as twisted ribbons with an estimated pitch of 2.4-3.2 microm. Length and width distributions of all samples were generally well described by log-normal functions, with the exception of tunicin, which had less lateral aggregation. AFM observation confirmed that the thickness of the nanocrystals was almost constant for a given origin and corresponded to the crystallite size measured from peak broadening in WAXS spectra. Experimental SAXS profiles were numerically simulated, combining the dimensions and size distribution functions determined by the various techniques. PMID:18052127

  5. Size-Selective Nanoparticle Assembly on Substrates by DNA Density Patterning.

    Science.gov (United States)

    Myers, Benjamin D; Lin, Qing-Yuan; Wu, Huanxin; Luijten, Erik; Mirkin, Chad A; Dravid, Vinayak P

    2016-06-28

    The vision of nanoscale self-assembly research is the programmable synthesis of macroscale structures with controlled long and short-range order that exhibit a desired set of properties and functionality. However, strategies to reliably isolate and manipulate the nanoscale building blocks based on their size, shape, or chemistry are still in their infancy. Among the promising candidates, DNA-mediated self-assembly has enabled the programmable assembly of nanoparticles into complex architectures. In particular, two-dimensional assembly on substrates has potential for the development of integrated functional devices and analytical systems. Here, we combine the high-resolution patterning capabilities afforded by electron-beam lithography with the DNA-mediated assembly process to enable direct-write grayscale DNA density patterning. This method allows modulation of the functionally active DNA surface density to control the thermodynamics of interactions between nanoparticles and the substrate. We demonstrate that size-selective directed assembly of nanoparticle films from solutions containing a bimodal distribution of particles can be realized by exploiting the cooperativity of DNA binding in this system. To support this result, we study the temperature-dependence of nanoparticle assembly, analyze the DNA damage by X-ray photoelectron spectroscopy and fluorescence microscopy, and employ molecular dynamics simulations to explore the size-selection behavior. PMID:27192324

  6. Influence of dispersion agents on particle size and concentration determined by laser-induced breakdown detection

    International Nuclear Information System (INIS)

    Laser-induced breakdown detection (LIBD) is a very promising analytical technique to determine the size and the concentration of nanoparticles (NPs) in aqueous suspensions. The measurement principle is based on the formation of individual plasma events selectively produced when a pulsed, focused laser beam hits a NP. The breakdown probability (BDP) is defined as the ratio of the number of plasma events detected to the total number of laser pulses applied. Energy curves are established by recording the BDP as a function of the laser energy which is increased in a stepwise manner. The size and the concentration of NPs in aqueous suspensions can be extracted from recorded energy curves. Although several studies have already documented the potential of the LIBD technique to detect NPs at trace concentrations in aqueous suspensions, the effect of dissolved matrix constituents (e.g. dispersion agents, which are frequently used to stabilize NPs in suspension) on the LIBD signal has not been addressed, yet. We therefore recorded energy curves of ultrahigh purity (UHP) water and NP suspensions both spiked with different dispersion agents at different concentrations. An increasing shift of the energy curves towards lower energies was observed with increasing concentrations of dispersion agents. The LIBD-derived size of the NPs was less affected by the presence of dispersion agents than the LIBD-derived particle number concentrations, which deviated by up to 300% from the expected values. The effects on the calculated concentrations were most pronounced at low (2 · 107 particles mL−1) NP concentrations and at higher NP concentrations (3 · 108 particles mL−1), the effect of the dispersion agents on the energy curves became negligible. These results show that dissolved matrix constituents substantially affect LIBD measurements, especially at low NP concentrations. - Highlights: • Dissolved constituents e.g. dispersion agents affect the LIBD signal. • Dispersion agents

  7. Size characterization by Sedimentation Field Flow Fractionation of silica particles used as food additives

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Four types of SiO2 particles were characterized by SdFFF, PCS and EM techniques. •Clusters of 10 nm nanoparticles were found in some SiO2 samples. •A method was set up to extract SiO2 particles from food matrices. •The effects of the carrier solution composition on SdFFF separations were evaluated. •Particle size distributions were obtained from SiO2 particles extracted from foodstuffs. -- Abstract: Four types of SiO2, available on the market as additives in food and personal care products, were size characterized using Sedimentation Field Flow Fractionation (SdFFF), SEM, TEM and Photon Correlation Spectroscopy (PCS). The synergic use of the different analytical techniques made it possible, for some samples, to confirm the presence of primary nanoparticles (10 nm) organized in clusters or aggregates of different dimension and, for others, to discover that the available information is incomplete, particularly that regarding the presence of small particles. A protocol to extract the silica particles from a simple food matrix was set up, enriching (0.25%, w w−1) a nearly silica-free instant barley coffee powder with a known SiO2 sample. The SdFFF technique, in conjunction with SEM observations, made it possible to identify the added SiO2 particles and verify the new particle size distribution. The SiO2 content of different powdered foodstuffs was determined by graphite furnace atomic absorption spectroscopy (GFAAS); the concentrations ranged between 0.006 and 0.35% (w w−1). The protocol to isolate the silica particles was so applied to the most SiO2-rich commercial products and the derived suspensions were separated by SdFFF; SEM and TEM observations supported the size analyses while GFAAS determinations on collected fractions permitted element identification

  8. Grain size, texture, and crystallinity in lanthanum monosulfide thin films grown by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Fairchild, S., E-mail: steven.fairchild@wpafb.af.mil [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States); Cahay, M. [School of Electronics and Computing Systems, University of Cincinnati, Cincinnati, Ohio 45221 (United States); Murray, P.T. [Research Institute, University of Dayton, Dayton, OH 45469-0170 (United States); Grazulis, L. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States); Wu, X.; Poitras, D.; Lockwood, D.J. [Institute for Microstructural Sciences, National Research Council, Ottawa, Ontario, Canada K1A OR6 (Canada)

    2012-12-01

    We report a detailed investigation of the growth of lanthanum monosulfide (LaS) thin films by pulsed laser deposition on (001) magnesium oxide (MgO) substrates in a background of H{sub 2}S for the purpose of optimizing their crystallinity, texture, and grain size. A variety of films were grown while varying the laser repetition rate, the temperature of the substrate, and the partial pressure of H{sub 2}S. The thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy, and high resolution transmission electron microscopy. Films grown at 500 Degree-Sign C with a H{sub 2}S background pressure of 3.4 Multiplication-Sign 10{sup -4} Pa and a laser repetition rate of 8 Hz produced the LaS film with the largest grains whose size averaged 293 nm. The XRD pattern of these films revealed that their orientation was predominantly (200). AFM images of the surface of these films showed large plate-like grains. This contrasts with the fine grain structure observed in LaS films grown at a lower substrate temperature and lower H{sub 2}S pressure. - Highlights: Black-Right-Pointing-Pointer LaS thin films were grown by pulsed laser deposition on MgO substrates in H{sub 2}S. Black-Right-Pointing-Pointer Deposition parameters were substrate temperature, H{sub 2}S pressure and repetition rate. Black-Right-Pointing-Pointer Film crystallinity, texture, and grain size were investigated. Black-Right-Pointing-Pointer The growth conditions for optimal texture and grain size are reported.

  9. Segregation by size difference in binary suspensions of fluid droplets in channel flow.

    Science.gov (United States)

    Makino, Masato; Sugihara-Seki, Masako

    2013-01-01

    In channel flow of multicomponent suspensions, segregation behavior of suspended components perpendicular to the flow direction is often observed, which is considered to be caused by the differential properties of the lateral migration depending on their shape, size, flexibility, and other characteristics. In the present study, we investigate the effect of size differences between suspended components on the segregation behavior, by a two-dimensional numerical simulation for binary dispersed suspensions of fluid droplets of two different sizes subjected to a plane Poiseuille channel flow. The small and large droplets are assumed to have equal surface tensions and equal viscosity ratios of internal to external fluids. The time evolutions of the lateral positions of large and small droplets relative to the channel centerline were computed by changing the area fraction of the small droplets in a mixture with a constant total area fraction. The large droplets are found to migrate closer to the channel centerline and the small droplets are found to migrate closer to the channel wall compared to the corresponding lateral positions in mono-dispersed suspensions at the same area fractions, although the mean lateral positions of the large and small droplets in mono-dispersed suspension are comparable. This segregation behavior as well as the margination of small droplets are enhanced when the size difference between large and small droplets is increased and the area fraction of large droplets is increased. These results may arise from higher tendencies for the large droplets to approach the channel centerline compared to the small droplets, which consequently expel small droplets from the central region toward the channel walls. PMID:23863280

  10. Sizes of water-soluble luminescent quantum dots measured by fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    In this paper, fluorescence correlation spectroscopy (FCS) was applied to measure the size of water-soluble quantum dots (QDs). The measurements were performed on a home-built FCS system based on the Stokes-Einstein equation. The obtained results showed that for bare CdTe QDs the sizes from FCS were larger than the ones from transmission electron microscopy (TEM). The brightness of QDs was also evaluated using FCS technique. It was found that the stability of the surface chemistry of QDs would be significantly improved by capping it with hard-core shell. Our data demonstrated that FCS is a simple, fast, and effective method for characterizing the fluorescent quantum dots, and is especially suitable for determining the fluorescent nanoparticles less than 10 nm in water solution

  11. Determination of nanoparticle size distribution together with density or molecular weight by 2D analytical ultracentrifugation

    KAUST Repository

    Carney, Randy P.

    2011-06-07

    Nanoparticles are finding many research and industrial applications, yet their characterization remains a challenge. Their cores are often polydisperse and coated by a stabilizing shell that varies in size and composition. No single technique can characterize both the size distribution and the nature of the shell. Advances in analytical ultracentrifugation allow for the extraction of the sedimentation (s) and diffusion coefficients (D). Here we report an approach to transform the s and D distributions of nanoparticles in solution into precise molecular weight (M), density (?P) and particle diameter (dp) distributions. M for mixtures of discrete nanocrystals is found within 4% of the known quantities. The accuracy and the density information we achieve on nanoparticles are unparalleled. A single experimental run is sufficient for full nanoparticle characterization, without the need for standards or other auxiliary measurements. We believe that our method is of general applicability and we discuss its limitations. 2011 Macmillan Publishers Limited. All rights reserved.

  12. Size distribution and radial density profile of synaptic vesicles by SAXS and light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Castorph, Simon; Salditt, Tim [Institute for X-ray Physics, Goettingen (Germany); Holt, Matthew; Jahn, Reinhard [Max Plank Institute for Biophysical Chemistry, Goettingen (Germany); Sztucki, Michael [European Synchrotron Radiation Facility, Grenoble (France)

    2008-07-01

    Synaptic vesicles are small membraneous organelles within the nerve terminal, encapsulating neurotransmitters by a lipid bilayer. The transport of the neurotransmitter, the fusion at the plasma membrane, and the release of the stored neurotransmitters into the synaptic cleft are since long know as essential step in nerve conduction of the chemical synapse. A detailed structural view of these molecular mechanisms is still lacking, not withstanding the enormous progress in the field during recent years. From measurements and quantitative fitting of small angle X-ray scattering curves and dynamic light scattering the averaged structural properties of synaptic vesicles can be determined. We present SAXS measurements and fits revealing the width of the size distribution function and details of the radial scattering length profile of synaptic vesicles from rat brain. Representative values for the inner and outer radius and the size polydispersity as well as the density and width of the outer protein layer are obtained.

  13. Latent image generation by soft landing of size-selected silver cluster cations

    International Nuclear Information System (INIS)

    We investigate the role of silver clusters in the photographic latent image generation. Silver cluster cations were produced in a sputtering arrangement, mass selected by a quadrupole mass filter and deposited with a well controlled kinetic energy onto photographic silver bromide crystals. The fraction of developed crystals after exposure of the samples to photographic developer was measured as a function of the size of the deposited clusters, the cluster coverage, the kinetic energy of the clusters, and the redox-potential of the developer. Development was observed after deposition of Ag4+ or larger aggregates, and, to a much lower extend, after deposition of the trimer. Silver monomers and dimers showed no photographic effect. Our data confirm that silver clusters above a critical size, which depends on the redox-potential of the developer, form the latent image in photography. (author)

  14. Structure and properties of nano-sized Eurofer 97 steel obtained by hydrostatic extrusion

    International Nuclear Information System (INIS)

    The objective of the present work was to apply hydrostatic extrusion to Eurofer 97 steel - a fusion relevant material that can be used for structural application in ITER. Samples were hydrostatically extruded in a multi-step process with a total true strain of about 4. Microstructure observations via light and transmission electron microscopy revealed significant grain size refinement from about 400 nm to 90 nm and changes in carbide size and distribution. Microstructure changes resulted in substantial improvement in mechanical properties of the material (the ultimate tensile strength and yield stress increase from 691 MPa to 1769 MPa and 582 MPa to 1641 MPa, respectively) which were evaluated by hardness measurements and tensile tests.

  15. Formation of vitamin E emulsion stabilized by octenylsuccinic starch: factors affecting particle size and oil load.

    Science.gov (United States)

    Qiu, Dan; Yang, Lei; Shi, Yong-Cheng

    2015-04-01

    Vitamin E (VE) emulsions were formed by adding VE acetate in an octenylsuccinic (OS) starch solution with distilled water and homogenizing with a microfluidizer at 20000 psi. The objective of this study was to investigate the effects of total concentration of starch and oil, ratio of oil to starch, pH value, and free OS content on emulsion properties. A method using HPLC was developed to analyze VE in emulsion, and the results were used to estimate the amount of surface VE oil. Lower total concentration of starch and oil and lower ratio of oil to starch resulted in more stable emulsions, whereas differences in the pH between 3 and 8 had little effect. Free OS content increased with greater particle size and decreased oil load. Increasing the number of passes reduced the initial particle size of the emulsion but increased free OS content. PMID:25808448

  16. Optimal receptor-cluster size determined by intrinsic and extrinsic noise

    CERN Document Server

    Aquino, Gerardo; Tollis, Sylvain; Endres, Robert G

    2011-01-01

    Biological cells sense external chemical stimuli in their environment using cell-surface receptors. To increase the sensitivity of sensing, receptors often cluster, most noticeably in bacterial chemotaxis, a paradigm for signaling and sensing in general. While amplification of weak stimuli is useful in absence of noise, its usefulness is less clear in presence of extrinsic input noise and intrinsic signaling noise. Here, exemplified on bacterial chemotaxis, we combine the allosteric Monod-Wyman- Changeux model for signal amplification by receptor complexes with calculations of noise to study their interconnectedness. Importantly, we calculate the signal-to-noise ratio, describing the balance of beneficial and detrimental effects of clustering for the cell. Interestingly, we find that there is no advantage for the cell to build receptor complexes for noisy input stimuli in absence of intrinsic signaling noise. However, with intrinsic noise, an optimal complex size arises in line with estimates of the sizes of ...

  17. Diffusion limited aggregation of particles with different sizes: Fractal dimension change by anisotropic growth

    Science.gov (United States)

    Braga, F. L.; Mattos, O. A.; Amorin, V. S.; Souza, A. B.

    2015-07-01

    Clusters formation models have been extensively studied in literature, and one of the main task of this research area is the analysis of the particle aggregation processes. Some work support that the main characteristics of this processes are strictly correlated to the cluster morphology, for example in DLA. It is expected that in the DLA clusters formation with particles containing different sizes the modification of the aggregation processes can be responsible for changes in the DLA morphology. The present article is going to analyze the formation of DLA clusters of particles with different sizes and show that the aggregates obtained by this approach generate an angle selection mechanism on dendritic growth that influences the shielding effect of the DLA edge and affect the fractal dimension of the clusters.

  18. Thermal conductivity of nanofluids and size distribution of nanoparticles by Monte Carlo simulations

    International Nuclear Information System (INIS)

    Nanofluids, a class of solid-liquid suspensions, have received an increasing attention and studied intensively because of their anomalously high thermal conductivites at low nanoparticle concentration. Based on the fractal character of nanoparticles in nanofluids, the probability model for nanoparticle's sizes and the effective thermal conductivity model are derived, in which the effect of the microconvection due to the Brownian motion of nanoparticles in the fluids is taken into account. The proposed model is expressed as a function of the thermal conductivities of the base fluid and the nanoparticles, the volume fraction, fractal dimension for particles, the size of nanoparticles, and the temperature, as well as random number. This model has the characters of both analytical and numerical solutions. The Monte Carlo simulations combined with the fractal geometry theory are performed. The predictions by the present Monte Carlo simulations are shown in good accord with the existing experimental data.

  19. Size dependent transitions induced by an electron collecting electrode near the plasma potential

    Science.gov (United States)

    Barnat, Edward; Laity, George; Hopkins, Matt; Baalrud, Scott

    2014-10-01

    As the size of a positively biased electrode increases, the nature of the interface formed between the electrode and the host plasma undergoes a transition from an electron-rich structure (electron sheath) to an intermediate structure containing both ion and electron rich regions (double layer) and ultimately forms an electron-depleted structure (ion sheath). In this study, measurements are performed to further test how the key scaling relationship relating the area of the electrode to that of the area of the vessel containing the plasma discharge impacts this transition. This was accomplished using a segmented disk electrode in which individual segments were individually biased to change the effective surface area of the anode. Measurements on bulk plasma parameters such as the collected current density, plasma potential, electron density, electron temperature and optical emission are made as both the size and the bias placed on the electrode are varied. Size dependent transitions in the voltage dependence of the plasma parameters are identified in both argon and helium discharges and are compared to the interface transitions predicted by global current balance. This work was supported by the Office of Fusion Energy Science at the U.S. Department of Energy under Contract DE-AC04-94SL85000.

  20. High Speed Size Sorting of Subcellular Organelles by Flow Field-Flow Fractionation.

    Science.gov (United States)

    Yang, Joon Seon; Lee, Ju Yong; Moon, Myeong Hee

    2015-06-16

    Separation/isolation of subcellular species, such as mitochondria, lysosomes, peroxisomes, Golgi apparatus, and others, from cells is important for gaining an understanding of the cellular functions performed by specific organelles. This study introduces a high speed, semipreparative scale, biocompatible size sorting method for the isolation of subcellular organelle species from homogenate mixtures of HEK 293T cells using flow field-flow fractionation (FlFFF). Separation of organelles was achieved using asymmetrical FlFFF (AF4) channel system at the steric/hyperlayer mode in which nuclei, lysosomes, mitochondria, and peroxisomes were separated in a decreasing order of hydrodynamic diameter without complicated preprocessing steps. Fractions in which organelles were not clearly separated were reinjected to AF4 for a finer separation using the normal mode, in which smaller sized species can be well fractionated by an increasing order of diameter. The subcellular species contained in collected AF4 fractions were examined with scanning electron microscopy to evaluate their size and morphology, Western blot analysis using organelle specific markers was used for organelle confirmation, and proteomic analysis was performed with nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS/MS). Since FlFFF operates with biocompatible buffer solutions, it offers great flexibility in handling subcellular components without relying on a high concentration sucrose solution for centrifugation or affinity- or fluorescence tag-based sorting methods. Consequently, the current study provides an alternative, competitive method for the isolation/purification of subcellular organelle species in their intact states. PMID:26005782

  1. Liposomes Size Engineering by Combination of Ethanol Injection and Supercritical Processing.

    Science.gov (United States)

    Santo, Islane Espirito; Campardelli, Roberta; Albuquerque, Elaine Cabral; Vieira De Melo, Silvio A B; Reverchon, Ernesto; Della Porta, Giovanna

    2015-11-01

    Supercritical fluid extraction using a high-pressure packed tower is proposed not only to remove the ethanol residue from liposome suspensions but also to affect their size and distribution leading the production of nanosomes. Different operating pressures, temperatures, and gas to liquid ratios were explored and ethanol was successfully extracted up to a value of 400 ppm; liposome size and distribution were also reduced by the supercritical processing preserving their integrity, as confirmed by Z-potential data and Trasmission Electron Microscopy observations. Operating at 120 bar and 38°C, nanosomes with a mean diameter of about 180 ± 40 nm and good storage stability were obtained. The supercritical processing did not interfere on drug encapsulation, and no loss of entrapped drug was observed when the water-soluble fluorescein was loaded as a model compound. Fluorescein encapsulation efficiency was 30% if pure water was used during the supercritical extraction as processing fluid; whereas an encapsulation efficiency of 90% was obtained if the liposome suspension was processed in water/fluorescein solution. The described technology is easy to scale up to an industrial production and merge in one step the solvent extraction, liposome size engineering, and an excellent drug encapsulation in a single operation unit. PMID:26211426

  2. Ratios of total suspended solids to suspended sediment concentrations by particle size

    Science.gov (United States)

    Selbig, W.R.; Bannerman, R.T.

    2011-01-01

    Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

  3. Selection of MOSFET Sizes by Fuzzy Sets Intersection in the Feasible Solutions Space

    Directory of Open Access Journals (Sweden)

    S. Polanco-Martagón

    2012-06-01

    Full Text Available A fuzzy sets intersection procedure to select the optimum sizes of analog circuits composed of metal-oxidesemiconductorfield-effect-transistors (MOSFETs, is presented. The cases of study are voltage followers (VFs and acurrent-feedback operational amplifier (CFOA, where the width (W and length (L of the MOSFETs are selected fromthe space of feasible solutions computed by swarm or evolutionary algorithms. The evaluation of three objectives,namely: gain, bandwidth and power consumption; is performed using HSPICETM with standard integrated circuit (ICtechnology of 0.35μm for the VFs and 180nm for the CFOA. Therefore, the intersection procedure among three fuzzysets representing “gain close to unity”, ”high bandwidth” and “minimum power consumption”, is presented. The mainadvantage relies on its usefulness to select feasible W/L sizes automatically but by considering deviation percentagesfrom the desired target specifications. Basically, assigning a threshold to each fuzzy set does it. As a result, theproposed approach selects the best feasible sizes solutions to guarantee and to enhance the performances of the ICsin analog signal processing applications.

  4. Layer-by-Layer Assembly Onto Gold Nanoparticles of Various Size

    Science.gov (United States)

    Kilroy, Andrew; Kessler, Sarah; Dobbins, Tabbetha

    This research focuses on the potential applications of coated gold nanoparticles in medicine. By coating gold nanoparticles in layers of polyelectrolytes, with a final layer of antibodies which targets chemicals uniquely exhibited by cancer cells, we eventually hope to selectively attach the nanoparticles to the cancer cells. The coated nanoparticles are assembled through layer-by-layer coulombic attraction due to the passive zeta potential of the particle and the charged nature of the polyelectrolytes. This poster will explore the potential usefulness of variously sized nanoparticles with various thickness of polyelectrolyte layers.

  5. Effect of weed patch size on seed removal by harvester ants

    OpenAIRE

    Westermann, Paula R.; Atanackovic, Valentina; Torra, Joel

    2014-01-01

    In dryland cereals in North-eastern Spain, the harvester ant, Messor barbarus L., is responsible for removal of a large proportion of the newly produced weed seeds (40-100%). The probability that seeds will be found by the ants may be influenced by weed patch size. To investigate this source of variability, 30 seed patches were created in each of three, 50 × 50 m, blocks in a cereal field after harvest, by sequentially seeding (10, 16 and 17 August 2010) with 2000 seeds m-2 of Avena sativa L....

  6. Improving Sunflower Halva Stability and Texture by Controlling Tahini Particle Size Distribution

    Directory of Open Access Journals (Sweden)

    Vlad Mureşan

    2015-05-01

    Full Text Available Sunflower halva is an appreciated product, but shows currently a quality below the expectations of the new generation of consumers, having a hard texture and oil exuded on the surface (low stability. The aim of this work was to assess the influence of tahini particle size on sunflower halva texture and stability. Eight different particle size sunflower tahini samples were produced at pilot plant scale, the higher the number of passes through the colloidal mill, the smaller the particle size (P1- coarsest → P8 - finest. Halva prototypes (25g / piece, including also an industrial sample (H0, were obtained at laboratory scale by mixing the nougat with tahini. The texture was evaluated on Stable micro systems TA.HD Plus texture analyzer equipped either with a cylinder probe or with a blade set. All samples were stored for 60 days at 4°C, room temperature (~25°C or 40°C. During storage, the colloidal stability of all samples was assessed by a gravimetric technique. Tahini samples P6 → P8 were not suitable for halva production while due to the low viscosities, the product was impossible to be shaped. Among obtained sunflower halva prototypes (H1 → H5 it was shown that decreasing tahini particle size decreased sunflower halva hardness and stability. For each sample, the increase of storage temperature decreased sunflower halva stability. Sunflower halva H3 was the most efficient, while was more stable and showed smaller hardness values than H0.

  7. Synthesis of aluminum oxide dispersed α-Fe with nano sized grains by simple milling

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Seung J., E-mail: sjhwang@daejin.ac.kr

    2015-07-25

    Highlights: • Nano-sized α-Fe with Al{sub 2}O{sub 3} dispersoid was produced by milling with elemental powders. • Milled powders were consolidated by Hot pressing and Hot Isostatic Pressing (HIP). • HIPed materials showed a homogeneous distribution of Al{sub 2}O{sub 3} in α-Fe nanocrystalline. • Yield strength of the HIPed materials was as high as 824 MPa. • Most of strengthening contributions are attributed to the Al{sub 2}O{sub 3} dispersoids. - Abstract: Aluminum oxide (with 4 volume% of Al{sub 2}O{sub 3}) dispersed α-Fe (BCC) with nano-sized grain was synthesized by reactive-cryogenic milling with a mixture of the elemental Fe, Al and Fe{sub 3}O{sub 4} (Magnetite) powders as a reactant. Prior to the Hot Isostatic Press (HIP) for further densification of the materials, the milled powders were hot pressed (HPed) at the elevated temperature. The microstructure of the consolidated materials was characterized by standard metallographic techniques such as TEM (Transmission Electron Microscopy), STEM–EDS (Energy Dispersive Spectroscopy), and XRD (X-ray Diffractometer). Mechanical properties of the materials were determined by compressive yield test and micro Vickers hardness test at room temperature. The grain size estimation was attempted for the materials by XRD, using the Scherrer formula and TEM pictures. The microstructure of the materials was comprised with a mixture of a homogeneous distribution of Fe and Al{sub 2}O{sub 3} nano grains. The 0.2% off-set yield strength and micro Vickers hardness of the materials were as high as 824 ± 39 MPa and 3.70 ± 0.1 GPa, respectively.

  8. Size characterization and quantification of exosomes by asymmetrical-flow field-flow fractionation.

    Science.gov (United States)

    Sitar, Simona; Kejžar, Anja; Pahovnik, David; Kogej, Ksenija; Tušek-Žnidarič, Magda; Lenassi, Metka; Žagar, Ema

    2015-09-15

    In the past few years extracellular vesicles called exosomes have gained huge interest of scientific community since they show a great potential for human diagnostic and therapeutic applications. However, an ongoing challenge is accurate size characterization and quantification of exosomes because of the lack of reliable characterization techniques. In this work, the emphasis was focused on a method development to size-separate, characterize, and quantify small amounts of exosomes by asymmetrical-flow field-flow fractionation (AF4) technique coupled to a multidetection system (UV and MALS). Batch DLS (dynamic light-scattering) and NTA (nanoparticle tracking analysis) analyses of unfractionated exosomes were also conducted to evaluate their shape and internal structure, as well as their number density. The results show significant influence of cross-flow conditions and channel thickness on fractionation quality of exosomes, whereas the focusing time has less impact. The AF4/UV-MALS and DLS results display the presence of two particles subpopulations, that is, the larger exosomes and the smaller vesicle-like particles, which coeluted in AF4 together with impurities in early eluting peak. Compared to DLS and AF4-MALS results, NTA somewhat overestimates the size and the number density for larger exosome population, but it discriminates the smaller particle population. PMID:26291637

  9. Nano sized bismuth oxy chloride by metal organic chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jagdale, Pravin, E-mail: pravin.jagdale@polito.it [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy); Castellino, Micaela [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Marrec, Françoise [Laboratory of Condensed Matter Physics, University of Picardie Jules Verne (UPJV), Amiens 80039 (France); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexicom (UNAM), Mexico D.F. 04510 (Mexico); Tagliaferro, Alberto [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy)

    2014-06-01

    Metal organic chemical vapour deposition (MOCVD) method was used to prepare thin films of bismuth based nano particles starting from bismuth salts. Nano sized bismuth oxy chloride (BiOCl) crystals were synthesized from solution containing bismuth chloride (BiCl{sub 3}) in acetone (CH{sub 3}-CO-CH{sub 3}). Self-assembly of nano sized BiOCl crystals were observed on the surface of silicon, fused silica, copper, carbon nanotubes and aluminium substrates. Various synthesis parameters and their significant impact onto the formation of self-assembled nano-crystalline BiOCl were investigated. BiOCl nano particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Micro-Raman spectroscopy. These analyses confirm that bismuth nanometer-sized crystal structures showing a single tetragonal phase were indeed bismuth oxy chloride (BiOCl) square platelets 18–250 nm thick and a few micrometres wide.

  10. Indentation Size Effects in Single Crystal Copper as Revealed by Synchrotron X-ray Microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Feng, G.; Budiman, A. S.; Nix, W. D.; Tamura, N.; Patel, J. R.

    2007-11-19

    The indentation size effect (ISE) has been observed in numerous nanoindentation studies on crystalline materials; it is found that the hardness increases dramatically with decreasing indentation size - a 'smaller is stronger' phenomenon. Some have attributed the ISE to the existence of strain gradients and the geometrically necessary dislocations (GNDs). Since the GND density is directly related to the local lattice curvature, the Scanning X-ray Microdiffraction ({mu}SXRD) technique, which can quantitatively measure relative lattice rotations through the streaking of Laue diffractions, can used to study the strain gradients. The synchrotron {mu}SXRD technique we use - which was developed at the Advanced Light Source (ALS), Berkeley Lab - allows for probing the local plastic behavior of crystals with sub-micrometer resolution. Using this technique, we studied the local plasticity for indentations of different depths in a Cu single crystal. Broadening of Laue diffractions (streaking) was observed, showing local crystal lattice rotation due to the indentation-induced plastic deformation. A quantitative analysis of the streaking allows us to estimate the average GND density in the indentation plastic zones. The size dependence of the hardness, as found by nanoindentation, will be described, and its correlation to the observed lattice rotations will be discussed.

  11. Species and size diversity in protective services offered by coral guard-crabs

    Directory of Open Access Journals (Sweden)

    C. Seabird McKeon

    2014-09-01

    Full Text Available Coral guard-crabs in the genus Trapezia are well-documented defenders of their pocilloporid coral hosts against coral predators such as the Crown-of-Thorns seastar (Acanthaster planci complex. The objectives of this study were to examine the protective services of six species of Trapezia against corallivory, and the extent of functional diversity among these Trapezia species. Studies conducted in Mo’orea, French Polynesia showed the Trapezia—coral mutualism protected the host corals from multiple predators through functional diversity in the assemblage of crab symbionts. Species differed in their defensive efficacy, but species within similar size classes shared similar abilities. Smaller-size Trapezia species, which were previously thought to be ineffective guards, play important defensive roles against small corallivores. We also measured the benefits of this mutualism to corals in the midst of an Acanthaster outbreak that reduced the live coral cover on the fore reef to less than 4%. The mutualism may positively affect the reef coral demography and potential for recovery during adverse predation events through shelter of multiple species of small corals near the host coral. Our results show that while functional diversity is supported within the genus, some Trapezia species may be functionally equivalent within the same size class, decreasing the threat of gaps in coral protection caused by absence or replacement of any single Trapezia species.

  12. Stabilization of microgrid with intermittent renewable energy sources by SMES with optimal coil size

    Science.gov (United States)

    Saejia, M.; Ngamroo, I.

    2011-11-01

    It is well known that the superconducting coil is the vital part of a superconducting magnetic energy storage (SMES) unit. This paper deals with the power controller design of a SMES unit with an optimal coil size for stabilization of an isolated microgrid. The study microgrid consists of renewable energy sources with intermittent power outputs i.e., wind and photovoltaic. Since power generations from such renewable sources are unpredictable and variable, these result in power fluctuations in a microgrid. To stabilize power fluctuations, a SMES unit with a fast control of active and reactive power can be applied. The structure of a power controller is the practical proportional-integral (PI). Based on the minimization of the variance of power fluctuations from renewable sources as well as the initial stored energy of SMES, the optimal PI parameters and coil size are automatically and simultaneously tuned by a particle swarm optimization. Simulation studies show that the proposed SMES controller with an optimal coil size is able to effectively alleviate power fluctuations under various power patterns from intermittent renewable sources.

  13. Crack lengths calculation by the unloading compliance technique for Charpy size specimens

    International Nuclear Information System (INIS)

    The problems with the crack length determination by the unloading compliance method are well known for Charpy size specimens. The final crack lengths calculated for bent specimens do not fulfil ASTM 1820 accuracy requirements. Therefore some investigations have been performed to resolve this problem. In those studies it was considered that the measured compliance should be corrected for various factors, but satisfying results were not obtained. In the presented work the problem was attacked from the other side, the measured specimen compliance was taken as a correct value and what had to be adjusted was the calculation procedure. On the basis of experimentally obtained compliances of bent specimens and optically measured crack lengths the investigation was carried out. Finally, a calculation procedure enabling accurate crack length calculation up to 5 mm of plastic deflection was developed. Applying the new procedure, out of investigated 238 measured crack lengths, more than 80% of the values fulfilled the ASTM 1820 accuracy requirements, while presently used procedure provided only about 30% of valid results. The newly proposed procedure can be also prospectively used in modified form for specimens of a size different than Charpy size. (orig.)

  14. Entropic effects, shape, and size of mixed micelles formed by copolymers with complex architectures.

    Science.gov (United States)

    Kalogirou, Andreas; Gergidis, Leonidas N; Moultos, Othonas; Vlahos, Costas

    2015-11-01

    The entropic effects in the comicellization behavior of amphiphilic AB copolymers differing in the chain size of solvophilic A parts were studied by means of molecular dynamics simulations. In particular, mixtures of miktoarm star copolymers differing in the molecular weight of solvophilic arms were investigated. We found that the critical micelle concentration values show a positive deviation from the analytical predictions of the molecular theory of comicellization for chemically identical copolymers. This can be attributed to the effective interactions between copolymers originated from the arm size asymmetry. The effective interactions induce a very small decrease in the aggregation number of preferential micelles triggering the nonrandom mixing between the solvophilic moieties in the corona. Additionally, in order to specify how the chain architecture affects the size distribution and the shape of mixed micelles we studied star-shaped, H-shaped, and homo-linked-rings-linear mixtures. In the first case the individual constituents form micelles with preferential and wide aggregation numbers and in the latter case the individual constituents form wormlike and spherical micelles. PMID:26651715

  15. Size enlargement of radioactive and hazardous species and their separation by microfiltration and ultrafiltration membranes

    International Nuclear Information System (INIS)

    Separation and volume reduction of aqueous solutions involving membranes is evolving into an expanding and diversified field. Numerous commercially successful membranes and their applications are now available. Among different driving forces used in membrane separation, pressure-driven separation has gained wide application. Depending on the size of the dissolved species in solution to be separated, the pressure needed to achieve the desired separation varies. The microfiltration and ultrafiltration membrane systems are low-pressure processes that generally operate below 350 kPa. To exploit these membranes in applications involving the removal of dissolved contaminants from solutions, it is essential to create a suitable size for the dissolved contaminants, so that the membranes can effectively retain them while producing a filtrate stream essentially free of contaminants. Size enlargement of the dissolved contaminants can be achieved through solution conditioning with the addition of one or a combination of chemical reagents and powdered materials. Examples of typical additives include: pH chemicals, polyelectrolytes, microorganisms and powdered adsorption/ion-exchange materials. In many situations, adequate control and optimization of the system chemistry and hydraulic conditions provide high selectivity and efficiency for contaminant removal. This paper summarizes removal efficiency data for cadmium, lead, mercury, uranium, arsenic, strontium-90/85, cesium-137 and iron. These data resulted from various initiatives on membrane technology undertaken during the past five years by the Waste Processing Technology group at Chalk River Laboratories. The technology involves size enlargement of contaminants present in waste solution, and their separation using either microfiltration or ultrafiltration. The data support remedial applications involving treatment of contaminated groundwater and soils

  16. Habitat-specific size structure variations in periwinkle populations ( Littorina littorea) caused by biotic factors

    Science.gov (United States)

    Eschweiler, Nina; Molis, Markus; Buschbaum, Christian

    2009-06-01

    Shell size distribution patterns of marine gastropod populations may vary considerably across different environments. We investigated the size and density structure of genetically continuous periwinkle populations ( Littorina littorea) on an exposed rocky and a sheltered sedimentary environment on two nearby islands in the south-eastern North Sea (German Bight). On the sedimentary shore, periwinkle density (917 ± 722 individuals m-2) was about three times higher than on the rocky shore (296 ± 168 individuals m-2). Mean (9.8 ± 3.9 mm) and maximum (22 mm) shell size of L. littorea on the sedimentary shore were smaller than on the rocky shore (21.5 ± 4.2 and 32 mm, respectively), where only few small snails were found. Additionally, periwinkle shells were thicker and stronger on the rocky than on the sedimentary shore. To ascertain mechanisms responsible for differences in population structures, we examined periwinkles in both environments for growth rate, predation pressure, infection with a shell boring polychaete ( Polydora ciliata) and parasitic infestation by trematodes. A crosswise transplantation experiment revealed better growth conditions on the sedimentary than on the rocky shore. However, crab abundance and prevalence of parasites and P. ciliata in adult snails were higher on the sedimentary shore. Previous investigations showed that crabs prefer large periwinkles infested with P. ciliata. Thus, we suggest that parasites and shell boring P. ciliata in conjunction with an increased crab predation pressure are responsible for low abundances of large periwinkles on the sedimentary shore while high wave exposure may explain low densities of juvenile L. littorea on the rocky shore. We conclude that biotic factors may strongly contribute to observed differences in size structure of the L. littorea populations studied on rocky and sedimentary shores.

  17. Size of bacterial ice-nucleation sites measured in situ by radiation inactivation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Govindarajan, A.G.; Lindow, S.E.

    1988-03-01

    Four bacterial species are known to catalyze ice formation at temperatures just below 0/sup 0/C. To better understand the relationship between the molecular structure of bacterial ice-nucleation site(s) and the quantitative and qualitative features of the ice-nucleation-active phenotype, the authors determined by ..gamma..-radiation analysis the in situ size of ice-nucleation sites in strains of Pseudomonas syringae and Erwinia herbicola and in Escherichia coli HB101 carrying the plasmid pICE1.1. Lyophilized cells of each bacterial strain were irradiated with a flux of ..gamma.. radiation from 0 to 10.2 Mrad. Differential concentrations of active ice nuclei decreased as a first-order function of radiation dose in all strains as temperature was decreased from -2/sup 0/C to -14/sup 0/C in 1/sup 0/C intervals. Sizes of ice nuclei were calculated from the /sup +/-radiation flux at which 37% of initial ice nuclei active within each 1/sup 0/C temperature interval remained. The minimum mass of a functional ice nucleus was about 150 kDa for all strains. The size of ice nuclei increased logarithmically with increasing temperature from -12/sup 0/CC to -2/sup 0/C, where the estimated nucleant mass was 19,000 kDa. The ice nucleant in these three bacterial species may represent an oligomeric structure, composed at least in part of an ice gene product that can self-associate to assume many possible sizes.

  18. Improved Light Conversion Efficiency Of Dye-Sensitized Solar Cell By Dispersing Submicron-Sized Granules Into The Nano-Sized TiO2 Layer

    Directory of Open Access Journals (Sweden)

    Song S.A.

    2015-06-01

    Full Text Available In this work, TiO2 nanoparticles and submicron-sized granules were synthesized by a hydrothermal method and spray pyrolysis, respectively. Submicron-sized granules were dispersed into the nano-sized TiO2 layer to improve the light conversion efficiency. Granules showed better light scattering, but lower in terms of the dye-loading quantity and recombination resistance compared with nanoparticles. Consequently, the nano-sized TiO2 layer had higher cell efficiency than the granulized TiO2 layer. When dispersed granules into the nanoparticle layer, the light scattering was enhanced without the loss of dye-loading quantities. The dispersion of granulized TiO2 led to increase the cell efficiency up to 6.51%, which was about 5.2 % higher than that of the electrode consisting of only TiO2 nanoparticles. Finally, the optimal hydrothermal temperature and dispersing quantity of granules were found to be 200°C and 20 wt%, respectively.

  19. Indication of the radiofrequency induced lesion size by pre-ablation measurements

    DEFF Research Database (Denmark)

    Stagegaard, Niels; Petersen, Helen Høgh; Chen, Xu;

    2005-01-01

    /s), two different contact pressures (10 or 30 g) and parallel or perpendicular electrode-tissue orientation using 7F 4 mm tip catheters. Prior to ablation the impedance rise (DeltaIMP) caused by the obtained contact and the temperature rise with a 0.6 W 5 s test pulse (DeltaT) were measured. Subsequently......BACKGROUND: During radiofrequency ablation of arrhythmias tissue heating and hence lesion size depend on electrode-tissue contact and cooling of the electrode tip caused by cavitary blood flow. These factors are unique and unknown for each catheter placement in the beating heart. A tool for...

  20. Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

    KAUST Repository

    Cates, Nichole C.

    2009-12-09

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

  1. Measurement of interactions between polysaccharides and flavour compounds by exclusion size chromatography: advantages and limits.

    Science.gov (United States)

    Guichard, E; Etiévant, P

    1998-12-01

    Interactions between flavour compounds and polysaccharides have been studied by exclusion size chromatography, the Hummel and Dreyer method. Hydrogen bonding was found between 2-acetyl thiazole and dextrines of different degrees of polymerisation. The number of binding sites and the affinity constant increase by increasing the degree of polymerisation. Hydrogen bonding was also responsible for the interactions between xanthane and 1-octen-3-ol or 2-acetyl pyrazine, with 1 mole of 1-octen-3-ol bound per pentasaccharide repeating unit. Unfortunately, the number of flavour compounds, which can be studied with this method, is limited due to their low water solubility and their low UV absorption. PMID:9881364

  2. New energy-saving and environmentally friendly technologies for buses and trucks; Nieuwe energiezuinige en milieuvriendelijke technologien voor bussen en vracthtwagens

    Energy Technology Data Exchange (ETDEWEB)

    Craps, R.; De Keukeleere, D.; Lenaers, G.

    1998-09-01

    The point of departure was the statement that people find public transport buses highly polluting. A lot of attention went to the advantages and the disadvantages of buses and trucks on liquefied petroleum gas (LPG) and natural gas. These fuels don`t cause any particle emissions from the combustion process. To quantify the other environmental advantages of gas technology, the Flemish Institute for Technological Research (VITO) carried out measurements of different bus technologies. Fuel consumption, emission of nitrogen oxides, carbon monoxides and hydrocarbons of 8 buses were measured in the Brussels traffic. 3 technologies of the early nineties were taken as a reference: the Euro-1 diesel, the current Brussels public transport company natural gas bus and a LPG bus. Comparisons were made with the modern diesel bus (Euro-2) and the newest buses on natural gas and LPG. To achieve minimal emissions, the best available technology for buses on natural gas or LPG is multipoint injection, the constructors of engines for heavy-duty traffic are changing from carburetor to fuel injection. The best available gas technologies has emissions that can be 50 to 95 per cent lower than the most modern diesel bus. Users mentioned problems at the introduction of vehicles on gas, such as lower reliability and availability. The cost price continues to be a disadvantage of buses and trucks on gas. The extra consumption of fuel doesn`t necessarily imply higher costs. Often fuel suppliers and distributors offer a favourable unit price, which includes the cost for the infrastructure. The purchase price of the vehicle remains higher and the workplaces must be adjusted for maintenance and repairs of vehicles on gas. The bus or truck on diesel is very reliable and cheaper to use than a similar vehicle on gas. The environmental perspectives are much less marked. Heavy-duty traffic emits nitrogen oxides and particles. With respect to these harmful substances in particular, constructors must

  3. Effect of particle size on microstructure and strength of porous spinel ceramics prepared by pore-forming in situ technique

    Indian Academy of Sciences (India)

    Wen Yan; Nan Li; Yuanyuan Li; Guangping Liu; Bingqiang Han; Juliang Xu

    2011-08-01

    The porous spinel ceramics were prepared from magnesite and bauxite by the pore-forming in situ technique. The characterization of porous spinel ceramics was determined by X-ray diffractometer (XRD), scanning electron microscopy(SEM), mercury porosimetry measurement etc and the effects of particle size on microstructure and strength were investigated. It was found that particle size affects strongly on the microstructure and strength. With decreasing particle size, the pore size distribution occurs from multi-peak mode to bi-peak mode, and lastly to mono-peak mode; the porosity decreases but strength increases. The most apposite mode is the specimens from the grinded powder with a particle size of 6.53 m, which has a high apparent porosity (40%), a high compressive strength (75.6MPa), a small average pore size (2.53 m) and a homogeneous pore size distribution.

  4. Exact equations for soil particle-size analysis by gamma-ray attenuation

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Elimoel Abraao; Bacchi, Osny Oliveira Santos; Reichardt, Klaus [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab, de Fisica do Solo

    1999-03-01

    Soil particle-size analysis by gamma-ray attenuation was first suggested in 1992 and improved in 1997 by diminishing the measurement time and adapting it for automation. It is here demonstrated that when the mass attenuation coefficient {mu}{sub w} and the density D{sub w} are replaced by {mu}{sub s} and D{sub s} (where the subscripts w and s stand for water and solution) in the approximate equations used to estimate the concentration of suspended particles, they become exact. The demonstration is based by treating the dispersant and water solution as one single medium, instead of treating them as two media In this way, six variables are reduced to only three. Physical considerations suggest that the precision in this analysis could be improved if other types of solutions and of photon energies would be used, so that the attenuation by the particles would differ more significantly from the attenuation by the solution. (author)

  5. Urban air quality improvement by using a CNG lean burn engine for city buses

    NARCIS (Netherlands)

    Merétei, T.; Ling, J.A.N. van; Havenith, C.

    1998-01-01

    The use of compressed natural gas (CNG)-fuelled lean-burn city bus engines has a significant potential for air quality improvement in urban areas. Particularly important is the reduction of NO, as well as particulate and non regulated HC-emissions. For this reason, a CNG-fuelled, lean-burn, turbocha

  6. Performance characteristic of endoscopic ultrasound-guided fine needle aspiration is unaffected by pancreatic mass size

    Science.gov (United States)

    Ramesh, Jayapal; Kim, Hwasoon; Reddy, Kartika; Eltoum, Isam-Eldin A.

    2016-01-01

    Background and study aims: Despite a well-established tool for diagnosis of pancreatic masses, endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) studies have shown suboptimal diagnostic performance at divergent mass sizes. Since the impact of gold standard follow-up and presence of on-site evaluation on this observation is unknown, we aimed to study the performance characteristics of EUS-FNA under these strict conditions. Patients and methods: EUS-FNA results from pancreatic mass lesions performed between July 2000 and March 2013 were evaluated. All patients with histological follow-up were then stratified into four groups: Group A ( ≤ 10 mm), Group B (11 – 20 mm), Group C (21 – 40 mm), and Group D (> 40 mm). Sensitivity and diagnostic accuracy were calculated for each group and compared. Results: A total of 612 /3832 (16 %) patients with pancreatic masses who underwent EUS-FNA had histology confirmation. Of these, 81 were excluded due to unavailable lesion size, while the rest formed the study cohort. Mean age (SD) was 65.8 years (9.3) with 51.2 % female. The mean number of passes for the entire cohort was 2.9 (SD 1.9; range 1 – 12); patients in group D had a significantly higher number of passes for on-site diagnosis (P = 0.0124). There was no significant difference between the groups for sensitivity (P = 0.1134) or diagnostic accuracy (P = 0.2111). Proportional trend analysis revealed no significant correlation between size and sensitivity (P = 0.6192). The size of lesion measured by EUS was not associated with sensitivity or specificity after adjusting for age, sex, and pancreatic location. Conclusion: In the presence of rapid on-site cytopathology and when final histology is taken as the gold standard, pancreatic mass size does not affect the performance characteristics of EUS-FNA. PMID:27092323

  7. Antagonistic control of muscle cell size by AMPK and mTORC1.

    Science.gov (United States)

    Mounier, Rémi; Lantier, Louise; Leclerc, Jocelyne; Sotiropoulos, Athanassia; Foretz, Marc; Viollet, Benoit

    2011-08-15

    Nutrition and physical activity have profound effects on skeletal muscle metabolism and growth. Regulation of muscle mass depends on a thin balance between growth-promoting and growth-suppressing factors. Over the past decade, the mammalian target of rapamycin (mTOR) kinase has emerged as an essential factor for muscle growth by mediating the anabolic response to nutrients, insulin, insulin-like growth factors and resistance exercise. As opposed to the mTOR signaling pathway, the AMP-activated protein kinase (AMPK) is switched on during starvation and endurance exercise to upregulate energy-conserving processes. Recent evidence indicates that mTORC1 (mTOR Complex 1) and AMPK represent two antagonistic forces governing muscle adaption to nutrition, starvation and growth stimulation. Animal knockout models with impaired mTORC1 signaling showed decreased muscle mass correlated with increased AMPK activation. Interestingly, AMPK inhibition in p70S6K-deficient muscle cells restores cell growth and sensitivity to nutrients. Conversely, muscle cells lacking AMPK have increased mTORC1 activation with increased cell size and protein synthesis rate. We also demonstrated that the hypertrophic action of MyrAkt is enhanced in AMPK-deficient muscle, indicating that AMPK acts as a negative feedback control to restrain muscle hypertrophy. Our recent results extend this notion by showing that AMPKα1, but not AMPKα2, regulates muscle cell size through the control of mTORC1 signaling. These results reveal the diverse functions of the two catalytic isoforms of AMPK, with AMPKα1 playing a predominant role in the control of muscle cell size and AMPKα2 mediating muscle metabolic adaptation. Thus, the crosstalk between AMPK and mTORC1 signaling is a highly regulated way to control changes in muscle growth and metabolic rate imposed by external cues. PMID:21799304

  8. Size of myocardial infarction induced by ischaemia/reperfusion is unaltered in rats with metabolic syndrome.

    Science.gov (United States)

    Thim, Troels; Bentzon, Jacob F; Kristiansen, Steen B; Simonsen, Ulf; Andersen, Heidi L; Wassermann, Karsten; Falk, Erling

    2006-06-01

    Obesity is associated with metabolic syndrome and increased incidence of and mortality from myocardial infarction. The aim of the present study was to develop an animal model with metabolic syndrome and examine how that influences size of myocardial infarcts induced by occlusion and reperfusion of the left anterior descending coronary artery. Sprague-Dawley rats (n = 105) were fed either LF (low-fat) or MHF (moderately high-fat) diets for 13 weeks before coronary occlusion for 45 min, followed by reperfusion for 60 min. Compared with LF-fed and lean MHF-fed rats, obese MHF-fed rats developed metabolic disturbances similar to those seen in the metabolic syndrome, including being overweight by 24% (compared with lean MHF-fed rats), having 74% more visceral fat (compared with LF-fed rats), 15% higher blood pressure (compared with LF-fed rats), 116% higher plasma insulin (compared with lean MHF-fed rats), 10% higher fasting plasma glucose (compared with LF-fed rats), 35% higher non-fasting plasma glucose (compared with lean MHF-fed rats), 36% higher plasma leptin (compared with lean MHF-fed rats) and a tendency to lower plasma adiponectin and higher plasma non-esterified fatty acids. Infarct size was similar in the three groups of rats (36+/-14, 42+/-18 and 41+/-14% in obese MHF-fed, lean MHF-fed and LF-fed rats respectively). In conclusion, rats fed a MHF diet developed metabolic syndrome, but this did not influence myocardial infarct size. PMID:16448385

  9. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    International Nuclear Information System (INIS)

    Beam diagnostics is an essential constituent of any accelerator, so that it is named as 'organs of sense' or 'eyes of the accelerator.' Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

  10. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chuyu [Peking Univ., Beijing (China)

    2012-12-31

    Beam diagnostics is an essential constituent of any accelerator, so that it is named as "organs of sense" or "eyes of the accelerator." Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

  11. ANALYSIS OF THE FEASIBILITY OF ESTABLISHMENT OF CONCEPTS OF LOGISTICS LEAN MANUFACTURING OF SUPPLY INTERNAL FROM A ASSEMBLER’S COMPANY OF BUSES

    Directory of Open Access Journals (Sweden)

    WILLIAN GABRIEL MIRANDA

    2010-09-01

    Full Text Available This work had as study object a assembler’s company of buses that is currently is in a big expansion process with lack of new ideas. Then, it comes the opportunity to combine this work with the needs and ambitions of the company. Therefore, will be a detailed study on the logistics of internal movement, analyzing what are the tools of logistics management used in the present, evaluating how is the performance from them and where there is the possibility of improvement in the supply process, based on the concepts of lean manufacturing and/or materials management tools. It will be assess also the possible barriers in the systems, through a survey of values in the activities performed by employees, evaluating fault points in the process, searching for appropriate and logical solutions to these issues. It is known that the complexity is high, and the consistency of this study to do proposals for a possible reorganization in the distribution system and planning, presenting theoretical and logical means for the possible benefits that the company would have to achieve excellence in the system of internal movement, obtaining thus more competitive in the market, increase productivity, providing areas for production and reduced lead time (period between the start of an activity until its end of supply. For the optimization of logistics must be synergy by all employees and also senior management and a study aimed at improving the supply system. The chances of success are high with these factors reconciled.

  12. Large 2D-arrays of size-controllable silver nanoparticles prepared by hybrid deposition

    Science.gov (United States)

    Dieu Thuy Ung, Thi; Hoa Nguyen, Thi; Liem Nguyen, Quang

    2016-09-01

    Two main results are presented in this paper. (i) Silver nanoparticles (AgNPs) with uniform size-distribution and controllability in the range of 20–50 nm were synthesized by seeding and growing at ambient conditions. The single-crystal Ag nano-seeds were created by reduction of AgNO3 in presence of citrate surfactant at 70 °C. Then, importantly, the fresh AgCl precursor was used in the presence of polyvinylpyrrolidone to adjust the reaction rate with ascorbic acid to generate Ag for growing on the surface of single-crystal Ag nano-seeds. The AgNPs size could be well-controlled by varying the amount of Ag nano-seeds while keeping the AgCl precursor concentration to be constant. (ii) The large 2D-arrays with homogeneous and dense monolayers of AgNPs were prepared on ITO substrates by hybrid method, in which the key technological point is the surface functionalization of AgNPs using mixed alkanethiols (dodecanethiol:octadecanethiol = 6:1). We have used the fabricated 2D-arrays from the 50 nm AgNPs as a surface enhanced Raman scattering substrate to take the Raman scattering spectra of rhodamine B (RhB), glucose and viral pathogen (H5N1) at very low concentrations of 10‑10 M, 10‑12 M and 4 ng μl‑1, respectively.

  13. Enhancement of island size by dynamic substrate disorder in simulations of graphene growth.

    Science.gov (United States)

    Enstone, Gwilym; Brommer, Peter; Quigley, David; R Bell, Gavin

    2016-06-01

    We demonstrate a new mechanism in the early stages of sub-monolayer epitaxial island growth, using Monte Carlo simulations motivated by experimental observations on the growth of graphene on copper foil. In our model, the substrate is "dynamically rough", by which we mean (i) the interaction strength between Cu and C varies randomly from site to site, and (ii) these variable strengths themselves migrate from site to site. The dynamic roughness provides a simple representation of the near-molten state of the Cu substrate in the case of real graphene growth. Counterintuitively, the graphene island size increases when dynamic roughness is included, compared to a static and smooth substrate. We attribute this effect to destabilisation of small graphene islands by fluctuations in the substrate, allowing them to break up and join larger islands which are more stable against roughness. In the case of static roughness, when process (ii) is switched off, island growth is strongly inhibited and the scale-free behaviour of island size distributions, present in the smooth-static and rough-dynamic cases, is destroyed. The effects of the dynamic substrate roughness cannot be mimicked by parameter changes in the static cases. PMID:27199250

  14. Characterization of nano-sized SiC@Ni composite fabricated by electroless plating method.

    Science.gov (United States)

    Xu, Zhan; Chen, Yigang

    2013-02-01

    A nano-sized SiC@Ni composite was prepared by simple electroless plating method. Nickel can be reduced by Na2H2PO2 under the catalysis of Pd to despite onto the surface of SiC nanoparticles. The composite structure was characterized by means of TEM images, XRD and the components were analyzed using EDS. The coating layer on the SiC particles was several nanometers thick and mainly in a form of fine Ni crystalline grain and amorphous Ni-P alloy. By increasing the concentration of Na2H2PO2 in the plating bath, the uniformity of the coating layer can be improved obviously. Both of the magnetism and crystallinity of Ni coatings depends on the P content in the coating which can be decreased by increasing the pH values of plating solutions. The SiC@Ni particles exhibited soft magnetic characteristics. PMID:23646660

  15. Effect of alkali on the size dispersity of mammalian DNA measured by filter elution.

    OpenAIRE

    van Ankeren, S C; Wheeler, K T

    1984-01-01

    DNA from unirradiated and irradiated cultured 9L rat brain tumor cells was held for varying times in low ionic strength solutions at pH 11.0, 12.3, or 12.9. The effect of this exposure to alkali on the DNA size distribution was determined by comparing the DNA filter elution profiles obtained experimentally with those theoretically predicted for monodispersed and random distributions. At pH 12.3 or 12.9, DNA from cells irradiated with 300 rad eluted with first-order kinetics corresponding to a...

  16. Separation of complex branched polymers by size-exclusion chromatography probed with multiple detection.

    Science.gov (United States)

    Gaborieau, Marianne; Nicolas, Julien; Save, Maud; Charleux, Bernadette; Vairon, Jean-Pierre; Gilbert, Robert G; Castignolles, Patrice

    2008-05-01

    Size-exclusion chromatography (SEC) separates polymers by hydrodynamic volume (the universal calibration principle). Molecular weights can be determined using viscometry (relying on universal calibration) and light scattering (independent of universal calibration). In the case of complex branched polyacrylates with tetrahydrofuran as eluent, universal calibration is valid, although the separation in term of molecular weight is incomplete: a given elution slice contains a range of molecular weights, described in terms of a 'local polydispersity'. The local polydispersity index decreases when the number of branches per chain increases and complete separation is reached for highly branched chains. PMID:18378255

  17. Sizing of the Haemophilus influenzae Rd genome by pulsed-field agarose gel electrophoresis.

    OpenAIRE

    Lee, J J; Smith, H O

    1988-01-01

    The four restriction enzymes ApaI (5'-GGGCCC), EagI (5'-CGGCCG), NaeI (5'-GCCGGC), and SmaI (5'-CCCGGG) were found to produce distributions of DNA fragment sizes useful for mapping of the Haemophilus influenzae Rd genome by pulsed-field agarose gel electrophoresis. ApaI produced 21 fragments (range, 1.6 to 305 kilobases [kb]), EagI yielded 30 fragments (0.6 to 339 kb), NaeI produced 32 fragments (2.3 to 290 kb), and SmaI yielded 16 fragments (6.0 to 377 kb). Summation of the fragment lengths ...

  18. Preparation and Size Characterization of Silver Nanoparticles Produced by Femtosecond Laser Ablation in Water

    Institute of Scientific and Technical Information of China (English)

    BIAN Fei; ZHANG Xin-Zheng; WANG Zhen-Hua; WU Qiang; HU nao; XU Jing-Jun

    2008-01-01

    @@ Femtosecond laser ablation of silver plate placed in water is used to produce nanoparticle suspension.The method is easy to operate and the suspension is relatively stable.The optical properties and the size distribution of the suspension are studied with UV-vis absorption spectroscopy and dynamic light scattering, respectively.The shape of the nanoparticles is investigated by an atomic force microscope, which is near spherical.There are two kinds of nanoparticles, small particles with diameter about 35 nm, and large particles with diameter about 12Ohm.

  19. Interdisciplinary Construction and Implementation of a Human sized Humanoid Robot by master students

    DEFF Research Database (Denmark)

    Helbo, Jan; Svendsen, Mads Sølver

    2009-01-01

    With limited funding it seemed a very good idea to encourage master students to design and construct their own human size biped robot.  Because this task is huge and very interdisciplinary different expertises were covered by students from different departments who in turn took over results from...... former students. In the last three years three student groups from respectively Department of Mechanical Engineering and Electronic Systems have been working on the project.  The robot AAU-BOT1 is designed, manufactured, assembled, instrumented and the time for walking should be possible in the near...

  20. Synthesis of Si nanoparticles with narrow size distribution by pulsed laser ablation

    International Nuclear Information System (INIS)

    We synthesized Si nanoparticles by pulsed nanosecond-laser ablation. We applied a positive voltage bias during laser irradiation and effectively reduced size distribution. Scanning electron micrographs of samples showed the nanoparticles to be highly non-agglomerated. Si nanoparticles have the average diameter of 4-5 nm, the geometrical standard deviation of 1.35, and the density of 1.6 x 1012/cm2. A MOS device showed excellent charge trap behavior with a flat-band voltage shift over 7 V, which can be applied for memory device applications.

  1. Optimization of solid state fermentation of sugar cane by Aspergillus niger considering particles size effect

    Energy Technology Data Exchange (ETDEWEB)

    Echevarria, J.; Rodriguez, L.J.A.; Delgado, G. (Instituto Cubano de Investigaciones de los Derivados de la Cana de Azucar (ICIDCA), La Habana (Cuba)); Espinosa, M.E. (Centro Nacional de Investigaciones Cientificas, La Habana (Cuba))

    1991-01-01

    The protein enrichment of sugar cane by solid state fermentation employing Aspergillus niger was optimized in a packed bed column using a two Factor Central Composit Design {alpha} = 2, considering as independent factors the particle diameter corresponding to different times of grinding for a sample and the air flow rate. It was significative for the air flow rate (optimum 4.34 VKgM) and the particle diameter (optimum 0.136 cm). The average particle size distribution, shape factor, specific surface, volume-surface mean diameter, number of particles, real and apparent density and holloweness for the different times of grinding were determined, in order to characterize the samples. (orig.).

  2. Size of bacterial ice-nucleation sites measured in situ by radiation inactivation analysis

    OpenAIRE

    Govindarajan, Arepura G.; Lindow, Steven E.

    1988-01-01

    Four bacterial species are known to catalyze ice formation at temperatures just below 0°C. To better understand the relationship between the molecular structure of bacterial ice-nucleation site(s) and the quantitative and qualitative features of the ice-nucleation-active phenotype, we determined by γ-radiation analysis the in situ size of ice-nucleation sites in strains of Pseudomonas syringae and Erwinia herbicola and in Escherichia coli HB101 carrying the plasmid pICE1.1 (containing a 4-kil...

  3. Shape-and size-controlled Ag nanoparticles stabilized by in situ generated secondary amines

    International Nuclear Information System (INIS)

    Highlights: • Ag nanoparticles were generated from Ag amido complexes AgNiPr2 and AgN(SiMe3)2. • Ag nanoparticles were stabilized by in situ generated HNiPr2 or HN(SiMe3)2. • 1 or 5 equiv. of ethylenediamine as additional capping agent decreases the average size of the particles. • Ethylenediamine favor the formation of spherical particles. - Abstract: Silver amides such as AgNiPr2 and AgN(SiMe3)2 have been employed successfully as precursors for the yield synthesis of silver nanoparticles under mild conditions of dihydrogen gas reduction (2 atm) in organic media. Transmission electron microscopy (TEM) showed the formation of silver nanoparticles with FCC structure, variously sized from 26 to 35 nm for AgNiPr2 and from 14 to 86 nm for AgN(SiMe3)2, the synthesis could take place in absence of added stabilizers due to the in situ formation of secondary amines from the reaction of dihydrogen gas with the amide ligands of the silver precursor. Indeed, the presence of HNR2 (R = iPr2, N(SiMe3)2) on the surface of the nanoparticle was confirmed by spectroscopic means. Finally, the addition of ethylenediamine as additional capping agent allowed not only the control of the structural characteristics of the resulting Ag nanoparticles (well-dispersed with spherical shape), but that regarding the nanoparticle size as it inhibited overgrowth, limiting it to ca. 25 nm

  4. Understorey Regeneration of Lophira alata as Affected by Seed Tree Size and Growing Conditions

    Directory of Open Access Journals (Sweden)

    Bongjoh, CA.

    2005-01-01

    Full Text Available Demographic pressure and slash and burn practices are two factors which reduce the number of Lophira alata plants in its natural range where it is more represented by young plants. The hypothesis that its understorey regeneration may be affected by seed tree size and growing conditions was investigated in the tropical moist forest in southern Cameroon using mature trees of various diameter classes for a sustainable management of the species. Biomass partitioning was also examined in regenerating seedlings growing in loading bays and forest understorey. Seedling density was highest when seed tree diameter at breast height (dbh was 100 cm or more. A strong positive correlation was found between seed tree diameter dbh and crown size expressed as mean diameter of projected crown area, but crown size correlated much better with seedling density. Compared with their counterparts of the same height growing in loading bays in full sunlight but devoid of litter and topsoil, seedlings found in understorey exhibited lower root: shoot ratio, indicating that soil-derived resources were more limiting in loading bays than on undisturbed forest floor. Leaf weight per area (leaf dry weight/leaf area (LWA and leaf packing (leaf number/cm shoot height were almost 2-fold greater in loading bays than in understorey. As seedlings seldom grew taller than 50 cm in the latter environment, it may be inferred that root: shoot ratio, LWA, and leaf packing can be used to assess the sustainability of growth and development of this pioneer species at the seedling stage.

  5. Shape-and size-controlled Ag nanoparticles stabilized by in situ generated secondary amines

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Meneses, E., E-mail: esther.ramirez@ibero.mx [Departamento de Ingeniería y Ciencias Químicas, Universidad Iberoamericana, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Distrito Federal C.P. 01219 (Mexico); Montiel-Palma, V. [Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001 Col. Chamilpa, Cuernavaca, Morelos C.P. 62209 (Mexico); Domínguez-Crespo, M.A.; Izaguirre-López, M.G. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada-IPN, Unidad Altamira. Km 14.5 Carretera Tampico-Puerto Industrial, 89600 Altamira, Tamaulipas (Mexico); Palacios-Gonzalez, E. [Laboratorio de Microscopia de Ultra alta Resolución, Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas No. 152, C.P. 07730 México D.F. (Mexico); Dorantes-Rosales, H. [Departamento de Metalurgia, E.S.I.Q.I.E.-I.P.N., Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación. Gustavo A. Madero, C.P. 07738 México D.F. (Mexico)

    2015-09-15

    Highlights: • Ag nanoparticles were generated from Ag amido complexes AgN{sup i}Pr{sub 2} and AgN(SiMe{sub 3}){sub 2}. • Ag nanoparticles were stabilized by in situ generated HN{sup i}Pr{sub 2} or HN(SiMe{sub 3}){sub 2}. • 1 or 5 equiv. of ethylenediamine as additional capping agent decreases the average size of the particles. • Ethylenediamine favor the formation of spherical particles. - Abstract: Silver amides such as AgN{sup i}Pr{sub 2} and AgN(SiMe{sub 3}){sub 2} have been employed successfully as precursors for the yield synthesis of silver nanoparticles under mild conditions of dihydrogen gas reduction (2 atm) in organic media. Transmission electron microscopy (TEM) showed the formation of silver nanoparticles with FCC structure, variously sized from 26 to 35 nm for AgN{sup i}Pr{sub 2} and from 14 to 86 nm for AgN(SiMe{sub 3}){sub 2}, the synthesis could take place in absence of added stabilizers due to the in situ formation of secondary amines from the reaction of dihydrogen gas with the amide ligands of the silver precursor. Indeed, the presence of HNR{sub 2} (R = iPr{sub 2}, N(SiMe{sub 3}){sub 2}) on the surface of the nanoparticle was confirmed by spectroscopic means. Finally, the addition of ethylenediamine as additional capping agent allowed not only the control of the structural characteristics of the resulting Ag nanoparticles (well-dispersed with spherical shape), but that regarding the nanoparticle size as it inhibited overgrowth, limiting it to ca. 25 nm.

  6. Perceptions of work environment priorities : Are there any differences by company size? — An ecological study

    OpenAIRE

    Nordlöf, Hasse; Wijk, Katarina; Westergren, Karl-Erik

    2015-01-01

    BACKGROUND: Earlier studies suggest that the quality of handling occupational health and safety (OHS) activities differs between companies of different sizes. Company size is a proxy variable for other variables affecting OHS performance. OBJECTIVE: The objective of this study was to investigate if there is an association between company size and perceptions of work environment prioritizations. METHODS: Data from 106 small- and medium-sized Swedish manufacturing companies was collected. One m...

  7. Clinical study of cardiogenic cerebral embolism; A comparison of lesion size by CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, Masayuki; Mitsuma, Terunori (Aichi Medical Univ., Nagakute (Japan)); Ishikawa, Sawao; Takeda, Akio; Tanaka, Hisashi

    1993-06-01

    In order to investigate the distribution of lesion size and to determine the background factors responsible for large infarcts, we examined CT findings in 88 consecutive patients with acute cardiogenic cerebral embolism of the internal carotid arterial system. Lesion size was determined by brain CT, and expressed as the 'infarct index'. The typical CT finding was a sharply marginated lesion in the cortex corresponding to the occluded arterial territory, accompanied by mass effect. Over half of the cases showed an infarct index of 20% or less. Most cases had small lesions, with substantially fewer cases having large infarcts. The lack of large infarcts was attributable to early recanalization of the occluded artery. Several background factors were implicated in the large infarcts, including elevated hematocrit, fibrinogen, arterial blood pressure, cardiothoracic ratio (as seen in chest X-rays), and a shortening of activated partial thromboplastin time (APTT). Factors implicated in the formation of a large embolus included increased blood viscosity and coagulability (caused by dehydration), and a hypertension-induced shift of the lower limit of autoregulation to a higher level. Further study is needed to determine whether such changes arise as the cause or the effect of a cerebral embolism. (author).

  8. Fabrication of nano-sized grains by pulsed laser surface melting

    International Nuclear Information System (INIS)

    In this work, the formation and characterization of nano-sized grains on the modified surfaces of GCr15 and H13 steels have been investigated. The material was processed by pulsed laser surface melting (LSM) under different depths of de-ionized water. The microstructures and phases of the melted zones were examined by x-ray diffraction, environmental field emission scanning electron microscopy and high resolution transmission electron microscopy. The results indicate that LSM under water can successfully fabricate nano-scaled grains on the surfaces of steel, due to the rapid solidification and crystallization by heterogeneous nucleation. The elemental segregation of chromium and activated heterogeneous nucleation mechanism of austenite in liquid metal play a key role in the formation of nano-sized grains at high cooling rates. This one-step technique provides us a new way to prepare uniform nano-scaled grains, and is of great importance for further understanding the growth of nano-materials under extreme conditions.

  9. Silicon and zinc telluride nanoparticles synthesized by pulsed laser ablation: Size distributions and nanoscale structure

    Energy Technology Data Exchange (ETDEWEB)

    Lowndes, D.H.; Rouleau, C.M.; Duscher, G. [and others

    1997-08-01

    Size distributions of Si and ZnTe nanoparticles produced by low energy density ArF (193 nm) pulsed laser ablation into ambient gases were measured as a function of the gas pressure and target-substrate separation, D{sub ts}, using atomic force microscopy (AFM) and high resolution scanning electron microscopy (HRSEM). For low energy density (Ed = 1.04 J/cm{sup 2}) ablation of Si into He at pressures of 0.5, 1.5, 4 and 10 torr, large nanoparticles were most numerous at D{sub ts} = 10 mm, with smaller nanoparticles found at 20 mm and 40 mm. For each D{sub ts} value a maximum of the mean nanoparticle diameter occurred for a He pressure near 6 torr, in contrast to other recent measurements in which the size of Si nanoparticles increased monotonically with the He pressure. High resolution Z-contrast transmission electron microscopy (HRZTEM) and electron energy loss spectroscopy (EELS) revealed that ZnTe nanoparticles formed by ablation into nitrogen at E{sub d} = 0.74 J/cm{sup 2} consisted of a crystalline ZnTe core surrounded by an amorphous ZnO shell. Growth defects and surface steps were clearly visible in the ZnTe crystalline core. The dependences of the mean diameter of ZnTe nanocrystals on nitrogen pressure and D{sub ts}, were qualitatively similar to those found for Si in He.

  10. Investigation of lithium diffusion in nano-sized rutile TiO2 by impedance spectroscopy

    International Nuclear Information System (INIS)

    The kinetics of the electrochemical lithium insertion reaction in nano-sized rutile TiO2 has been investigated using ac impedance spectroscopy. The experimental data are obtained for a rutile compound synthesized via a solution technique and characterized by a morphology corresponding to spherical particles made of a large number of very thin nanorods 20 nm thick. The results are discussed as a function of the Li content x for 0 xTiO2, the temperature over the range 10-50 oC and the number of discharge-charge cycles. The significant linear decrease of the chemical diffusion coefficient DLivs. the lithium content and the high values of DLi found in the composition range 0 2 is obtained; the value of 0.35 eV being much lower than that reported from computational experiments for the micro-sized oxide. This work also demonstrates a new system takes place from the second cycle, characterized by a significant improvement of Li diffusion by a factor five and allowing high rates to be used.

  11. Hardening by ion implantation of VT1-0 alloy having different grain size

    Energy Technology Data Exchange (ETDEWEB)

    Nikonenko, Alisa, E-mail: aliska-nik@mail.ru; Kurzina, Irina, E-mail: kurzina99@mail.ru [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation); Popova, Natalya, E-mail: natalya-popova-44@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation); Nikonenko, Elena, E-mail: vilatomsk@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: kmp1980@mail.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation)

    2016-01-15

    The paper presents a transmission electron microscopy (TEM) study of the structural and phase state of commercially pure titanium implanted by aluminum ions. TEM study has been carried out for two types of grains, namely coarse (0.4 µm) and small (0.5 µm). This paper presents details of the yield stress calculations and the analysis of strength components for the both grain types in two areas of the modified layer: at a distance of 0-150 nm (surface area I) and ∼300 nm (central area II) from the irradiated surface. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress in areas I and II. Thus, near the ion-alloyed layer, the yield stress decreases with the increase of the grain size, whilst area II demonstrates its increase. Moreover, the contribution to the general hardening of the alloy made by certain hardening mechanisms differs from contributions made by each of these mechanisms in each certain case.

  12. Grain size stabilization of nanocrystalline copper at high temperatures by alloying with tantalum

    International Nuclear Information System (INIS)

    Highlights: •A mean grain size of 167 nm is retained after annealing at 97% of the melting point. •Hardness surpasses conventional pure nanocrystalline Cu by 2.5 GPa. •Extreme stability is attributed to both thermodynamic and kinetic stabilization. -- Abstract: Nanocrystalline Cu–Ta alloys belong to an emerging class of immiscible materials with potential for high-temperature applications. Differential scanning calorimetry (DSC), Vickers microhardness, transmission and scanning electron microscopy (TEM/SEM), and atomistic simulations have been applied to study the structural evolution in high-energy cryogenically alloyed nanocrystalline Cu–10 at.%Ta. The thermally induced coarsening of the as-milled microstructure was investigated and it was found that the onset of grain growth occurs at temperatures higher than that for pure nanocrystalline Cu. The total heat release associated with grain growth was 0.553 kJ/mol. Interestingly, nanocrystalline Cu–10 at.%Ta maintains a mean grain size (GS) of 167 nm after annealing at 97% of its melting point. The increased microstructural stability is attributed to a combination of thermodynamic and kinetic stabilization effects which, in turn, appear to be controlled by segregation and diffusion of Ta solute atoms along grain boundaries (GBs). The as-milled nanocrystalline Cu–10 at.%Ta exhibits Vickers microhardness values near 5 GPa surpassing the microhardness of conventional pure nanocrystalline Cu by ∼2.5 GPa

  13. Enhanced wettability performance of ultrathin ZnO nanotubes by coupling morphology and size effects

    Science.gov (United States)

    Yang, Peihua; Wang, Kun; Liang, Zhiwen; Mai, Wenjie; Wang, Cheng-Xin; Xie, Weiguang; Liu, Pengyi; Zhang, Long; Cai, Xiang; Tan, Shaozao; Song, Jinhui

    2012-08-01

    In this work, we report on the detailed characterization and mechanism analysis of the improved wettability performance of a new type of ZnO nanostructure, the ultrathin ZnO nanotube, whose growth is induced by screw-dislocation. The newly discovered enhanced wettability properties are suggested to be caused by coupling the morphology and size effects of the nanostructured surface. These ultrathin nanotubes with low density and small dimension form a wet-hair-like hierarchical morphology, which shows a further improved superhydrophobic property with an 8.6 +/- 1.6° larger contact angle than that of ZnO nanorods due to the morphology effect. In addition, owing to the large surface to volume ratio and increased effective UV-irradiated area of the ultrathin tubular structure, the ZnO nanotubes exhibit ~5 times faster superhydrophobicity to superhydrophilicity conversion speed than nanorods under 254 nm UV illumination. Furthermore, UV light with a wavelength of 254 nm exhibits ~40 times faster wettability conversion speed for nanotubes than that of 365 nm, which is suggested to be a result of the band gap shift at the nanoscale. The combined advantages of enhanced superhydrophobicity, improved sensitivity, and faster conversion speed by coupling morphology and size effects of these ZnO nanotubes should give them broad applications in self-cleaning surfaces and wettability switches.

  14. Determinants of Supply and Demand for Trade Credit by Micro, Small and Medium-Sized Enterprises

    Directory of Open Access Journals (Sweden)

    Claudinê Jordão de Carvalho

    2015-08-01

    Full Text Available This article investigates the determinant factors of supply and demand for trade credit by micro, small and medium-sized enterprises (MSMEs, using data collected in a survey of managers from 481 firms in 32 cities in the states of São Paulo and Minas Gerais (Brazil between 2008 and 2010. The multivariate relationship model proposed here is grounded in trade credit, agency and transaction costs theories. This study is based on a technique known as path analysis that uses a system of simple regressions estimated by simultaneous equations. The main results show the following: (i trade credit and short-term bank loans are supplementary (and not substitute sources of funds for MSMEs, which demonstrates that trade credit can be used by financial institutions as an indicator of the creditworthiness of the company; (ii the proportion of credit sales, the days sales outstanding measure and sales growth are positively related to the amount of trade credit demanded, which suggests that trade credit is transferred along the supply chain; and (iii the supply of trade credit is positively related to the importance that management ascribes to both internal capital and bank credit, which illustrates the strategic use of the supply of trade credit to increase sales. These results have important implications for companies' managers, financial institutions and the government agencies responsible for formulating policies that support and promote the development of small and medium-sized enterprises.

  15. Particle size control of silver nanoparticles prepared by pulsed wire discharge in liquid media

    International Nuclear Information System (INIS)

    Silver nanoparticles were prepared by pulsed wire discharge (PWD) using silver wire in deionized water at various relative energy (K) from 10 to 98, which is ratio of the charged energy of the capacitor in the electrical circuit to the vaporization energy of the wire. From energy deposition calculated by the measured voltage and current waveforms, deposited energy of the wire was increased with increasing K. From X-ray diffraction (XRD) analysis, prepared nanoparticles were phase identified as silver. From transmission electron microscopy observations, the shape of prepared silver nanoparticles were spherical and the median particle diameter (D50) and the geometric standard deviation (σg) were calculated from the particle distribution. D50 was decreased from 34 to 19 nm with increasing K. The particle size in prepared by PWD in liquid media can be controlled by K.

  16. Lysozyme refolding at high concentration by dilution and size-exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This study of renaturation by dilution and size exclusion chromatography (SEC) addition of urea to improve yield as well as the initial and final protein concentrations showed that although urea decreased the rate of lysozyme refolding, it could suppress protein aggregation to sustain the pathway of correct refolding at high protein concentration; and that there existed an optimum urea concentration in renaturation buffer. Under the above conditions, lysozyme was successfully refolded from initial concentration of up to 40 mg/mL by dilution and 100 mg/mL by SEC, with the yield of the former being more than 40% and that of the latter being 34.8%. Especially, under the condition of 30 min interval time, i.e. τ>2(tR2-tR1), the efficiency was increased by 25% and the renaturation buffer could be recycled for SEC refolding in continuous operation of downstream process.

  17. Chemical erosion by deuterium impact on carbon films doped with nanometer-sized carbide crystallites

    International Nuclear Information System (INIS)

    The erosion by 30 and 200 eV/D at temperatures between 300 and 1100 K was investigated for magnetron-sputtered films, consisting of carbon and metal (2-7 at.% W, Ti, Zr) present as nanometer-sized carbide crystallites. The total erosion yield was determined from weight-loss measurements and film thickness changes measured by RBS. The chemical erosion yield was obtained from the CD4 signal of mass spectrometry. The total erosion yield of doped films is reduced by a factor of 3-20 compared to pure C films. The CD4 production yield decreases less implying that the distribution of the chemically eroded species was changed by the dopants. Therefore, measuring only CD4 production or its spectroscopic signature could yield to misleading values and interpretations

  18. Dislocation structure and crystallite size in severely deformed copper by X-ray peak profile analysis

    International Nuclear Information System (INIS)

    Copper specimens were severely deformed by equal channel angular pressing (ECAP) up to eight passes. The microstructure was studied by X-ray diffraction peak profile analysis as a function of strain (ε). It was found that the crystallite size is reduced to a few tens of nanometers already at ε = 0.7 and it does not change significantly during further deformation. At the same time, the dislocation density increases gradually up to ε = 4. The dipole character of the dislocation structure becomes stronger with increasing strain. The thermal stability of the microstructure is examined by differential scanning calorimetry (DSC). The temperature of the DSC peak related to the recovery of the microstructure decreases with increasing strain. At the beginning of the heat release, a bimodal grain structure develops indicated by a special double-peak shape of the diffraction line profiles

  19. SCOPING STUDIES TO DEVELOP A METHOD TO DETERMINE PARTICLE SIZE IN SIMULANT SLUDGE SLURRIES BY SIEVING

    International Nuclear Information System (INIS)

    A physical separation method (i.e. sieving) was investigated to determine particle size distribution in non-radioactive sludge slurry simulants with the goal of implementation into the SRNL (Savannah River National Laboratory) shielded cells for use with radioactive sludge slurries. The investigation included obtaining the necessary experimental equipment, developing accessory equipment for use with the sieve shaker (to be able to sieve simulant slurries with aqueous solutions), sieving three different simulant slurries through a number of sieves and determining the particle size distribution gravimetrically, and developing a sufficient cleaning protocol of the sieves for re-use. The experimental protocol involved successive sieving of a NIST standard (to check the particle size retention of the sieves) and three non-radioactive slurry simulants (Batch 3 Tank 40 Test 3, Tank 40 Drum 3 and CETL Sludge Batch 2, which had been previously characterized by Microtrac analysis) through smaller and smaller sieves (150 microns x 5 microns) via use of the wet sieving system or by hand. For each of the three slurries, duplicate experiments were carried out using filtered supernate and DI water (to check the accuracy of the method versus Microtrac data) to sieve the slurry. Particle size determinations using the wet sieving system with DI water agree well with Microtrac data on a volume basis and in some cases the sieving data may be more accurate particularly if the material sieved had large particles. A correction factor had to be applied to data obtained from experiments done with supernate due to the dissolved solids which dried upon the sieves in the drying stage of the experiments. Upon subtraction of the correction factors, the experimental results were very similar to those obtained with DI water. It should be noted that approximately 250 mL of each of three simulant slurries was necessary to have enough filtered supernate available to carry out the experiments. The

  20. Size dependent disruption of tethered lipid bilayers by functionalized polystyrene nanoparticles.

    Science.gov (United States)

    Liu, Ying; Mark Worden, R

    2015-01-01

    Molecular interactions between engineered nanomaterials (ENM) and biomembranes are not well understood. This study investigated the effects of particle size and surface functional group on polystyrene nanoparticles' (PNPs) potency for biomembrane disruption. Electrochemical impedance spectroscopy was used to measure changes in the electrical resistance (Rm) of a tethered bilayer lipid membrane BLM (tBLM) composed of 1,2-dioleoyl-sn-glycero-phosphocholine (DOPC) following PNP exposure. All PNPs tested triggered a decline in the Rm that could be described using an exponential-decay model. Statistical hierarchical clustering analysis of two model parameters (exponential rate constant and fractional loss of Rm) could distinguish between the PNPs based on both size and surface functional group. For COOH modified nanoparticles, 20nm PNPs were more potent in reducing Rm than 100nm PNP. However, for amidine modified nanoparticles, 120nm PNPs were more potent in reducing Rm than 23nm PNP. The COOH modified PNPs were more potent in reducing Rm than amidine modified PNP, which tended to aggregate following exposure to a tBLM. Ultra performance liquid chromatography-mass spectroscopy analysis suggested that the aggregation may have been triggered by DOPC that was removed from the tBLM by the amidine PNP. PMID:25285435

  1. Size and structure of the Chicxulub crater revealed by horizontal gravity gradients and cenotes

    Science.gov (United States)

    Hildebrand, A. R.; Pilkington, M.; Connors, M.; Ortiz-Aleman, C.; Chavez, R. E.

    1995-08-01

    IT is now widely believed that a large impact occurred on the Earth at the end of the Cretaceous period, and that the buried Chicxulub structure in Yucatán, Mexico, is the resulting crater24. Knowledge of the size and internal structure of the Chicxulub crater is necessary for quantifying the effects of the impact on the Cretaceous environment. Although much information bearing on the crater's structure is available, diameter estimates range from 170 to 300 km (refs 1á¤-7), corresponding to an order of magnitude variation in impact energy. Here we show the diameter of the crater to be ~180 km by examining the horizontal gradient of the Bouguer gravity anomaly over the structure. This size is confirmed by the distribution of karst features in the Yucatan region (mainly water-filled sinkholes, known as cenotes). The coincidence of cenotes and peripheral gravity-gradient maxima suggests that cenote formation is closely related to the presence of slump faults near the crater rim.

  2. Effects of Crystalline Anisotropy and Indenter Size on Nanoindentation by Multiscale Simulation

    Directory of Open Access Journals (Sweden)

    Li Junwan

    2009-01-01

    Full Text Available Abstract Nanoindentation processes in single crystal Ag thin film under different crystallographic orientations and various indenter widths are simulated by the quasicontinuum method. The nanoindentation deformation processes under influences of crystalline anisotropy and indenter size are investigated about hardness, load distribution, critical load for first dislocation emission and strain energy under the indenter. The simulation results are compared with previous experimental results and Rice-Thomson (R-T dislocation model solution. It is shown that entirely different dislocation activities are presented under the effect of crystalline anisotropy during nanoindentation. The sharp load drops in the load–displacement curves are caused by the different dislocation activities. Both crystalline anisotropy and indenter size are found to have distinct effect on hardness, contact stress distribution, critical load for first dislocation emission and strain energy under the indenter. The above quantities are decreased at the indenter into Ag thin film along the crystal orientation with more favorable slip directions that easy trigger slip systems; whereas those will increase at the indenter into Ag thin film along the crystal orientation with less or without favorable slip directions that hard trigger slip systems. The results are shown to be in good agreement with experimental results and R-T dislocation model solution.

  3. Characterization of Particle Size Distributions of Powdery Building Material Aerosol Generated by Fluidization and Gravitation

    Directory of Open Access Journals (Sweden)

    Tadas Prasauskas

    2012-10-01

    Full Text Available This study aims to identify particle size distributions (PSD of aerosol of powdery building materials commonly used in construction work (cement, chalk, clay, wood sawdust, wood grinding dust, gypsum, hydrated lime, masonry grout, quartz sand, sand and structural lime by two aerosolization methods: fluidization and gravitation. Fluidization and gravitation methods represent industrial activities such as pneumotransportation and unloading. Both particle resuspension mechanisms have been modelled in laboratory conditions. The particle size distributions of resuspended particulate matter from powdery building materials were rather similar identified by both fluidization and gravitation methods, with an exception of wood sawdust and sand. The PM10 fraction ranged between 30% and 87%, PM2.5 from 7% to 28% and PM1.0 from 3% to 7% of the total mass of particulate matter. The highest PM10/PMtotal ratio was calculated for masonry grout - 0.87, and the lowest ratio for quartz sand - 0.30. The highest ratio of PM2.5/PMtotal was calculated for sand - 0.23, the lowest for quartz sand - 0.07. Substantial quantities of PM2.5 were found to be emitted implying a potential threat to human health.DOI: http://dx.doi.org/10.5755/j01.erem.61.3.1519

  4. Micron-sized particles detected in the vicinity of Jupiter by the Voyager plasma wave instruments

    Science.gov (United States)

    Tsintikidis, D.; Gurnett, D. A.; Kurth, W. S.; Granroth, L. J.

    Wideband waveform data obtained by the plasma wave instruments onboard the Voyager 1 and 2 spacecraft have been used to study micron-sized dust particles in the vicinity of Jupiter. The technique used was developed during the fly by s of Saturn, Uranus, and Neptune, and makes use of the fact that a particle striking the spacecraft at 10-20 km/s causes a voltage pulse in the plasma wave receiver. The waveform of the voltage pulse is much different than the waveform of plasma waves and provides a highly reliable method of detecting micron-sized dust particles. Although the dust impact rate observed in the vicinity of Jupiter is much lower than the rates at Saturn, Uranus, and Neptune, the particles are easily detectable. Approximately 1200 48-second frames of wideband waveform data were examined in the vicinity of Jupiter. Dust impact signatures were found in approximately 20% of these frames. The peak impact rates are about 1 impact per second, and the peak number densities are about 10-5 m-3. Most of the impacts occurred near the equatorial plane at radial distances less than about 35 RJ from Jupiter. Analysis of the detection threshold indicates that the particles have masses greater than 10-11 g, which corresponds to particles with diameters of a few micrometers or larger.

  5. Plot-size for 15N-fertilizer recovery studies by tanzania-grass

    International Nuclear Information System (INIS)

    The understanding of the N dynamics in pasture ecosystems can be improved by studies using the 15N tracer technique. However, in these experiments it must be ensured that the lateral movement of the labeled fertilizer does not interfere with the results. In this study the plot-size requirements for 15N-fertilizer recovery experiments with irrigated Panicum maximum cv. Tanzania was determined. Three grazing intensities (light, moderate and intensive grazing) in the winter, spring and summer seasons were considered. A 1 m2 plot-size, with a grass tussock in the center, was adequate, irrespective of the grazing intensity or season of the year. Increasing the distance from the area fertilized with 15N negatively affected the N derived from fertilizer (Npfm) recovered in herbage.The lowest decline in Npfm values were observed for moderate and light grazing intensities. This fact might be explained by the vigorous growth characteristics of these plants. Increasing the grazing intensity decreased the tussock mass and, the smaller the tussock mass, the greater was the dependence on fertilizer nitrogen. (author)

  6. Small size TiO{sub 2} nanoparticles prepared by laser ablation in water

    Energy Technology Data Exchange (ETDEWEB)

    Barreca, F., E-mail: process@anmresearch.it [Advanced and Nano Materials Research s.r.l., Salita Sperone 31, I-98166, Messina (Italy); Acacia, N. [Dipartimento di Fisica della Materia e Ingegneria Elettronica, Universita di Messina, Salita Sperone 31, I-98166, Messina (Italy); Barletta, E.; Spadaro, D.; Curro, G. [Advanced and Nano Materials Research s.r.l., Salita Sperone 31, I-98166, Messina (Italy); Neri, F. [Dipartimento di Fisica della Materia e Ingegneria Elettronica, Universita di Messina, Salita Sperone 31, I-98166, Messina (Italy)

    2010-08-15

    Titanium dioxide nanoparticles in distilled H{sub 2}O solvent were prepared by laser ablation. The experiments were performed irradiating a Ti target with a second harmonic (532 nm) output of a Nd:YAG laser varying the operative fluence between 1 and 10 J cm{sup -2} and for an ablation time ranging from 10 to 30 min. Electron microscopy measurements have evidenced the predominant presence of nanoparticles with diameter smaller than 10 nm together with agglomerations of 100-200 nm whose content increases with the laser fluence. At low laser fluence the particles' size distribution shows that more than 85% of the nanoparticles have a size smaller than 5 nm while at mid and high fluences the presence of 5-7 nm nanoparticles is predominant. XPS analysis has revealed the presence of different titanium suboxide phases with the prevalence of Ti-O bonds from TiO{sub 2} species. The optical bandgap values, determined by UV-vis absorption measurements, are compatible with the anatase phase.

  7. Nano-sized Particles Formed by Pulsed Discharge of Powders Sealed in Heat-shrinkable Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, S; Suematsu, H; Nakayama, T; Suzuki, T; Niihara, K, E-mail: ishihara@etigo.nagaokaut.ac.jp [Extreme Energy-Density Research Institute, Nagaoka University of Tech. 1603-1 Kamitomioka, Nagaoka 940-2188 (Japan)

    2011-03-15

    Pulsed wire discharge has been developed as a method to form nano-sized particles, wherein a large electrical current pulse is passed through a thin metal wire. Various wire materials have been used to form nano-sized particles by this method so far. However, materials which are not sufficiently ductile to form thin wires are unsuitable for this method. We have developed a new method for powders to be discharged to form nano-scale particles instead of wires. The powders were placed in heat-shrinkable tubes and sealed by heating. Short metal wires were set at both the ends of each tube for electrical connection to the electrodes of the discharge equipment. These tubes were set in a chamber whose atmosphere could be controlled. A large current pulse was then applied to the powders in the tubes. SiC particles with a cubic crystalline structure were synthesized in N{sub 2} gas from mixed powders of Si and C with a C/Si molar ratio of unity. However, mostly the Si phase remained in the particles. Then, mixed powders with a C/Si ratio of 2 were discharged. The obtained particles were mainly composed of the SiC phase, although Si and graphite phases remained mingled.

  8. Nano-sized Particles Formed by Pulsed Discharge of Powders Sealed in Heat-shrinkable Tubes

    Science.gov (United States)

    Ishihara, S.; Suematsu, H.; Nakayama, T.; Suzuki, T.; Niihara, K.

    2011-03-01

    Pulsed wire discharge has been developed as a method to form nano-sized particles, wherein a large electrical current pulse is passed through a thin metal wire. Various wire materials have been used to form nano-sized particles by this method so far. However, materials which are not sufficiently ductile to form thin wires are unsuitable for this method. We have developed a new method for powders to be discharged to form nano-scale particles instead of wires. The powders were placed in heat-shrinkable tubes and sealed by heating. Short metal wires were set at both the ends of each tube for electrical connection to the electrodes of the discharge equipment. These tubes were set in a chamber whose atmosphere could be controlled. A large current pulse was then applied to the powders in the tubes. SiC particles with a cubic crystalline structure were synthesized in N2 gas from mixed powders of Si and C with a C/Si molar ratio of unity. However, mostly the Si phase remained in the particles. Then, mixed powders with a C/Si ratio of 2 were discharged. The obtained particles were mainly composed of the SiC phase, although Si and graphite phases remained mingled.

  9. Preparation of nanometer-sized black iron oxide pigment by recycling of blast furnace flue dust

    International Nuclear Information System (INIS)

    Blast furnace (BF) flue dust is one of pollutants emitted by iron and steel plants. The recycling of BF flue dust can not only reduce pollution but also bring social and environmental benefits. In this study, leaching technique was employed to the treatment of BF flue dust at first. A mixed solution of ferrous and ferric sulfate was obtained and used as raw material to prepare nanometer-sized black iron oxide pigment (Fe3O4, magnetite) with NaOH as precipitant. The optimal technological conditions including total iron ion concentration, Fe3+/Fe2+ mole ratio, precipitant concentration and reaction temperature were studied and discussed carefully. The spectral reflectance and oil absorption were used as major parameters to evaluate performance of pigment. Furthermore, Fe3O4 particles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Under optimized conditions obtained pigment has low average spectral reflectance (<4%), good oil absorption (∼23%), high black intensity, and narrow size distribution 60-70 nm.

  10. Optimization of Comminution Circuit Throughput and Product Size Distribution by Simulation and Control

    Energy Technology Data Exchange (ETDEWEB)

    S.K. Kawatra; T.C. Eisele; T. Weldum; D. Larsen; R. Mariani; J. Pletka

    2005-07-01

    The goal of this project was to improve energy efficiency of industrial crushing and grinding operations (comminution). Mathematical models of the comminution process were used to study methods for optimizing the product size distribution, so that the amount of excessively fine material produced could be minimized. The goal was to save energy by reducing the amount of material that was ground below the target size, while simultaneously reducing the quantity of materials wasted as ''slimes'' that were too fine to be useful. Extensive plant sampling and mathematical modeling of the grinding circuits was carried out to determine how to correct this problem. The approaches taken included (1) Modeling of the circuit to determine process bottlenecks that restrict flowrates in one area while forcing other parts of the circuit to overgrind the material; (2) Modeling of hydrocyclones to determine the mechanisms responsible for retaining fine, high-density particles in the circuit until they are overground, and improving existing models to accurately account for this behavior; and (3) Evaluation of the potential of advanced technologies to improve comminution efficiency and produce sharper product size distributions with less overgrinding. The mathematical models were used to simulate novel circuits for minimizing overgrinding and increasing throughput, and it is estimated that a single plant grinding 15 million tons of ore per year saves up to 82.5 million kWhr/year, or 8.6 x 10{sup 11} BTU/year. Implementation of this technology in the midwestern iron ore industry, which grinds an estimated 150 million tons of ore annually to produce over 50 million tons of iron ore concentrate, would save an estimated 1 x 10{sup 13} BTU/year.

  11. The occultation of Kappa Geminorum by Eros. [stellar occultation observed for asteroid size and shape

    Science.gov (United States)

    Oleary, B.; Marsden, B. G.; Dragon, R.; Hauser, E.; Mcgrath, M.; Backus, P.; Robkoff, H.

    1976-01-01

    The paper discusses predictions and observations of the occultation of Kappa Gem by (433) Eros on January 24, 1975. Several positive and negative observations made in western New England are described. Local circumstances for the occultation are reconstructed, and the size and shape of Eros are determined analytically as well as graphically. The calculations yield two extremes for the cross section: a circle 23 km in diameter or a somewhat irregular figure 20 km by 6 or 7 km. Arguments based on the expected albedo of the asteroid suggest that the circle should be warped into an ellipse 21 by 13 km or that the irregular figure might be one component of a dumbbell-like profile.

  12. Size-dependent antimicrobial properties of sugar-encapsulated gold nanoparticles synthesized by a green method

    Science.gov (United States)

    Badwaik, Vivek D.; Vangala, Lakshmisri M.; Pender, Dillon S.; Willis, Chad B.; Aguilar, Zoraida P.; Gonzalez, Matthew S.; Paripelly, Rammohan; Dakshinamurthy, Rajalingam

    2012-11-01

    The antimicrobial properties of dextrose-encapsulated gold nanoparticles (dGNPs) with average diameters of 25, 60, and 120 nm (± 5) and synthesized by green chemistry principles were investigated against both Gram-negative and Gram-positive bacteria. Studies were performed involving the effect of dGNPs on the growth, morphology, and ultrastructural properties of bacteria. dGNPs were found to have significant dose-dependent antibacterial activity which was also proportional to their size. Experiments revealed the dGNPs to be bacteriostatic as well as bactericidal. The dGNPs exhibited their bactericidal action by disrupting the bacterial cell membrane which leads to the leakage of cytoplasmic content. The overall outcome of this study suggests that green-synthesized dGNPs hold promise as a potent antibacterial agent against a wide range of disease-causing bacteria by preventing and controlling possible infections or diseases.

  13. Intake of silica nanoparticles by giant lipid vesicles: influence of particle size and thermodynamic membrane state

    Directory of Open Access Journals (Sweden)

    Florian G. Strobl

    2014-12-01

    Full Text Available The uptake of nanoparticles into cells often involves their engulfment by the plasma membrane and a fission of the latter. Understanding the physical mechanisms underlying these uptake processes may be achieved by the investigation of simple model systems that can be compared to theoretical models. Here, we present experiments on a massive uptake of silica nanoparticles by giant unilamellar lipid vesicles (GUVs. We find that this uptake process depends on the size of the particles as well as on the thermodynamic state of the lipid membrane. Our findings are discussed in the light of several theoretical models and indicate that these models have to be extended in order to capture the interaction between nanomaterials and biological membranes correctly.

  14. Dislocation Analysis for Large-sized Sapphire Single Crystal Grown by SAPMAC Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, large-sized sapphire (Φ230×210 mm, 27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at the cooled center). Dislocation peculiarity in large sapphire boule (0001) basal plane was investigated by chemical etching, scanning electron microscopy and X-ray topography method. The triangular dislocation etch pit measured is 7.6×101~8.0×102 cm-2, in which relative high-density dislocations were generated at both initial and final stages of crystal growth. The analysis of single-crystal X-ray topography shows that there are no apparent sub-grain boundaries; the dislocation lines are isolated and straight. Finally, the origins of low-density dislocation in sapphire crystal are discussed by numerical analysis method.

  15. 2D size, position and shape definition of defects by B-scan image analysis

    Directory of Open Access Journals (Sweden)

    Michele Scafidi

    2015-10-01

    Full Text Available The non-destructive evaluation of defects by automatic procedures is of great importance for structural components. Thanks to the developments of the non-contact ultrasonic techniques, the automation of the inspections is gaining a progressively important role. In this work, an automatic inspection technique for the evaluation of defects by the analysis of B-scan images obtained by a laser ultrasonic system is presented. The data are extracted directly from a B-scan map obtained for a panel with internal defects, and are used to build an image of the cross section of the panel. The proposed automatic procedure allows the definition of size, position and shape of defects in panels of known thickness

  16. Rapid Synthesis of Size-controlled Gold Nanoparticles by Complex Intramolecular Photoreduction

    Institute of Scientific and Technical Information of China (English)

    DONG Shou-an; YANG Sheng-chun; TANG Chun

    2007-01-01

    A rapid synthesis of size-controlled gold nanoparticles was proposed. The method is based on the sensitive intramolecular photoreduction reaction of Fe( Ⅲ )-EDTA complex in chloroacetic acid-sodium acetate buffer solution,where Fe(Ⅱ)-EDTA complex generated by photo-promotion acts as a reductant of AuCl4- ions. Gold nanoparticles formed were stabilized by EDTA ligand or other protective agents added. As a result, well-dispersed gold nanoparticles with an average diameter range of 6.7 to 50. 9 nm were obtained. According to the characterizations by the UV spectrum and TEM, the intramolecular charge transfer of the excited states of complex Fe(Ⅲ) -EDTA and the mechanism of forming gold nanoparticles were discussed in detail.

  17. Particle size effects in Fischer-Tropsch synthesis by Co catalyst supported on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Ali Nakhaei Pour; Elham Hosaini; Mohammad Izadyar; Mohammad Reza Housaindokht

    2015-01-01

    The effect of Co particle size on the Fischer-Tropsch synthesis (FTS) activity of carbon nanotube (CNT)-supported Co catalysts was investigated. Microemulsion (using water-to-surfactant molar ratios of 2 to12) and impregnation techniques were used to prepare catalysts with different Co particle sizes. Kinetic studies were performed to understand the effect of Co particle size on catalytic activity. Size-dependent kinetic parameters were developed using a thermodynamic method, to evaluate the structural sensitivity of the CNT-supported Co catalysts. The size-independent FTS reaction rate constant and size-independent adsorption parameter increased with increasing reac-tion temperature. The Polani parameter also depended on catalyst particle size, because of changes in the catalyst surface coverage.

  18. Multiple mating reveals complex patterns of assortative mating by personality and body size.

    Science.gov (United States)

    Montiglio, Pierre-Olivier; Wey, Tina W; Chang, Ann T; Fogarty, Sean; Sih, Andrew

    2016-01-01

    Understanding patterns of non-random mating is central to predicting the consequences of sexual selection. Most studies quantifying assortative mating focus on testing for correlations among partners' phenotypes in mated pairs. Few studies have distinguished between assortative mating arising from preferences for similar partners (expressed by all or a subset of the population) vs. from phenotypic segregation in the environment. Also, few studies have assessed the robustness of assortative mating against temporal changes in social conditions. We tracked multiple matings by stream water striders (Aquarius remigis) across variable social conditions to investigate mating patterns by both body size and behavioural type (personality). We documented temporal changes in partner availability and used a mixed model approach to analyse individual behaviours and changes in mating status recorded on an hourly basis. We assessed whether all or only a subset of individuals in the population expressed a tendency to mate with similar phenotypes. Our analyses took into account variation in the level of competition and in the phenotypes of available partners. Males and females exhibited significant assortative mating by body size: the largest males and females, and the smallest males and females mated together more often than random. However, individuals of intermediate size were equally likely to mate with small, intermediate or large partners. Individuals also displayed two contrasting patterns of assortative mating by personality (activity level). Individuals generally mated preferentially with partners of similar activity level. However, beyond that general trend, individuals with more extreme personalities tended to exhibit disassortative mating: the most active males mated disproportionately with less active females and the least active males tended to mate with more active females. Our analyses thus revealed multiple, distinct patterns of nonrandom mating. These mating

  19. Control of the kerf size and microstructure in Inconel 738 superalloy by femtosecond laser beam cutting

    Science.gov (United States)

    Wei, J.; Ye, Y.; Sun, Z.; Liu, L.; Zou, G.

    2016-05-01

    Femtosecond laser beam cutting is becoming widely used to meet demands for increasing accuracy in micro-machining. In this paper, the effects of processing parameters in femtosecond laser beam cutting on the kerf size and microstructure in Inconel 738 have been investigated. The defocus, pulse width and scanning speed were selected to study the controllability of the cutting process. Adjusting and matching the processing parameters was a basic enhancement method to acquire well defined kerf size and the high-quality ablation of microstructures, which has contributed to the intensity clamping effect. The morphology and chemical compositions of these microstructures on the cut surface have been characterized by a scanning electron microscopy equipped with an energy dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Additionally, the material removal mechanism and oxidation mechanism on the Inconel 738 cut surface have also been discussed on the basis of the femtosecond laser induced normal vaporization or phase explosion, and trapping effect of the dangling bonds.

  20. Study of droplet size and velocity of fuel containing CO2 spray by means of PDA

    Institute of Scientific and Technical Information of China (English)

    XIAO Jin; QIAO Xinqi; HUANG Zhen; FANG Junhua

    2004-01-01

    Injection of fuel containing CO2 has potential to reduce NOx and soot emissions in a diesel engine. This paper presents an experimental study on the spray characteristics of fuel containing CO2 as measured by phase doppler anemometry (PDA). Experiments were performed under atmospheric conditions on diesel hole-type nozzles at constant injection pressure. Effects of CO2 concentration in diesel fuel on the spray pattern, droplet size and velocity were measured. Experimental results show that fuel atomization will improve greatly when the concentration of dissolved CO2 in the fuel exceeds the critical value. The axial and radial velocity of the fuel spray containing CO2 is larger than that of conventional diesel fuel spray near the nozzle exit due to flash boiling phenomena. Downstream of the spray, the radial velocity and droplet size of fuel containing CO2 is much more uniform and smaller than that of pure diesel spray. It is attributed to the greatly enhanced liquid-gas mixing resulting from flash separation of CO2 from the liquid. New insight into the atomization of the fuel containing CO2 was obtained and a possible mechanism to explain the phenomena was proposed. The method may be developed into a new technique for controlling diesel combustion and exhaust emissions.

  1. Micron-sized structure in a thin glycerol film revealed by fluorescent probes.

    Science.gov (United States)

    Xia, Ted; Xiao, Liantuan; Orrit, Michel

    2009-12-01

    We report on micrometer-sized structures in supercooled glycerol observed by imaging fluorescent probes at the temperatures close to, but above, the glass transition temperature (190 K). Two distinct heterogeneous patterns of the fluorescence intensity were detected, depending on how fast the sample was cooled down. In a slowly cooled sample, we observed a Swiss cheese-like pattern in which many micrometer-sized dark spots were nucleated in a bright background. A quickly cooled sample resulted in a spinodal decomposition pattern where many bright island-like features on micrometer scale were dispersed in a dark matrix. Similar patterns were seen earlier in triphenyl phosphite, another molecular liquid, which shows solid-like behavior at temperatures above its glass transition. Once the heterogeneous patterns are formed in the glycerol, they can persist for days, unless the samples are heated above 260 K for more than 10 h. Such heterogeneous patterns are ascribed to differential dye distributions in the glycerol film, pointing to long-lived and micrometer-scale density fluctuations in supercooled glycerol. The observation of such heterogeneity may provide additional understanding on how supercooled glycerol behaves before it turns into a glass. PMID:19929008

  2. LUNAR DUST GRAIN CHARGING BY ELECTRON IMPACT: DEPENDENCE OF THE SURFACE POTENTIAL ON THE GRAIN SIZE

    International Nuclear Information System (INIS)

    The secondary electron emission is believed to play an important role for the dust charging at and close to the lunar surface. However, our knowledge of emission properties of the dust results from model calculations and rather rare laboratory investigations. The present paper reports laboratory measurements of the surface potential on Lunar Highlands Type regolith simulants with sizes between 0.3 and 3 μm in an electron beam with energy below 700 eV. This investigation is focused on a low-energy part, i.e., ≤100 eV. We found that the equilibrium surface potential of this simulant does not depend on the grain size in our ranges of grain dimensions and the beam energies, however, it is a function of the primary electron beam energy. The measurements are confirmed by the results of the simulation model of the secondary emission from the spherical samples. Finally, we compare our results with those obtained in laboratory experiments as well as those inferred from in situ observations.

  3. Built Environment Influences of Children's Physical Activity: Examining Differences by Neighbourhood Size and Sex.

    Science.gov (United States)

    Mitchell, Christine A; Clark, Andrew F; Gilliland, Jason A

    2016-01-01

    Neighbourhoods can facilitate or constrain moderate-to-vigorous physical activity (MVPA) among children by providing or restricting opportunities for MVPA. However, there is no consensus on how to define a child's neighbourhood. This study examines the influence of the neighbourhood built environment on objectively measured MVPA among 435 children (aged 9-14 years) in London (ON, Canada). As there is no consensus on how to delineate a child's neighbourhood, a geographic information system was used to generate measures of the neighbourhood built environment at two buffer sizes (500 m and 800 m) around each child's home. Linear regression models with robust standard errors (cluster) were used to analyze the relationship between built environment characteristics and average daily MVPA during non-school hours on weekdays. Sex-stratified models assessed sex-specific relationships. When accounting for individual and neighbourhood socio-demographic variables, park space and multi-use path space were found to influence children's MVPA. Sex-stratified models found significant associations between MVPA and park space, with the 800 m buffer best explaining boys' MVPA and the 500 m buffer best explaining girls' MVPA. Findings emphasize that, when designing built environments, programs, and policies to facilitate physical activity, it is important to consider that the size of the neighbourhood influencing a child's physical activity may differ according to sex. PMID:26784212

  4. Curvature of double-membrane organelles generated by changes in membrane size and composition.

    Directory of Open Access Journals (Sweden)

    Roland L Knorr

    Full Text Available Transient double-membrane organelles are key players in cellular processes such as autophagy, reproduction, and viral infection. These organelles are formed by the bending and closure of flat, double-membrane sheets. Proteins are believed to be important in these morphological transitions but the underlying mechanism of curvature generation is poorly understood. Here, we describe a novel mechanism for this curvature generation which depends primarily on three membrane properties: the lateral size of the double-membrane sheets, the molecular composition of their highly curved rims, and a possible asymmetry between the two flat faces of the sheets. This mechanism is evolutionary advantageous since it does not require active processes and is readily available even when resources within the cell are restricted as during starvation, which can induce autophagy and sporulation. We identify pathways for protein-assisted regulation of curvature generation, organelle size, direction of bending, and morphology. Our theory also provides a mechanism for the stabilization of large double-membrane sheet-like structures found in the endoplasmic reticulum and in the Golgi cisternae.

  5. Built Environment Influences of Children’s Physical Activity: Examining Differences by Neighbourhood Size and Sex

    Directory of Open Access Journals (Sweden)

    Christine A. Mitchell

    2016-01-01

    Full Text Available Neighbourhoods can facilitate or constrain moderate-to-vigorous physical activity (MVPA among children by providing or restricting opportunities for MVPA. However, there is no consensus on how to define a child’s neighbourhood. This study examines the influence of the neighbourhood built environment on objectively measured MVPA among 435 children (aged 9–14 years in London (ON, Canada. As there is no consensus on how to delineate a child’s neighbourhood, a geographic information system was used to generate measures of the neighbourhood built environment at two buffer sizes (500 m and 800 m around each child’s home. Linear regression models with robust standard errors (cluster were used to analyze the relationship between built environment characteristics and average daily MVPA during non-school hours on weekdays. Sex-stratified models assessed sex-specific relationships. When accounting for individual and neighbourhood socio-demographic variables, park space and multi-use path space were found to influence children’s MVPA. Sex-stratified models found significant associations between MVPA and park space, with the 800 m buffer best explaining boys’ MVPA and the 500 m buffer best explaining girls’ MVPA. Findings emphasize that, when designing built environments, programs, and policies to facilitate physical activity, it is important to consider that the size of the neighbourhood influencing a child’s physical activity may differ according to sex.

  6. How perception of ultra-high definition is modified by viewing distance and screen size

    Science.gov (United States)

    Lachat, Amélie; Gicquel, Jean-Charles; Fournier, Jérôme

    2015-01-01

    Ultra High Definition (UHD) is a new technology, which main idea is to improve user's perception of details and sensation of immersion in comparison with High Definition systems (HD). However, it is important to understand the influence of the new UHD technical parameters on user's perception. Hence, to investigate the influence of the viewing distance, screen size and scene content on perceived video quality and feelings of users, a series of subjective experiments with four different contents (3 documentaries and 1 sport content) shooted by UHD camera were performed. These contents were displayed using three different image resolutions (SD, HD, UHD) and two UHD displays (55-inch and 84-inch). Each subject had to assess content for three different viewing distances (1.5, 3, 4.5 times of the screen height corresponding to optimal viewing distances of respectively UHD, HD, and close to SD optimal distance). Finally, 72 test conditions were evaluated. For each scene, observers reported their opinion on the perceived video quality using a 5-grade subjective scale. Results have shown that viewing distance has a significant influence on perceived quality. Moreover the highest MOS was obtained at optimal viewing for UHD, with a small difference between HD an UHD. At 3H and 4.5H, there is no difference from a statistical point of view. Screen size influences the perception of quality but not in the same way for the three image resolution and three viewing distances.

  7. Sequential learning of relative size by the Neotropical ant Gigantiops destructor.

    Science.gov (United States)

    Beugnon, Guy; Macquart, David

    2016-04-01

    The question of whether insects can perform concept learning or can use the geometry of space as in mammals has been recently addressed in Hymenoptera in an extensive way. We investigate here the ability of the tropical ant Gigantiops destructor to perform sequential learning and to use size relationships during navigation. Ants were trained to solve a dichotomic six-stage linear maze relying on the apparent width of two vertical landmarks. Each individual ant first learnt to associate a given landmark width to the motor decision of turning right or left to avoid dead-ends independently of a motor routine. When confronted for the first time with a new intermediate-sized pattern, for which no supposed snapshot could have been stored, ants made directional choices indicating that bar width judgments were not absolute but rather relative to the familiar visual patterns seen in the previous chambers. This result demonstrates that ants can generalize relationship rules by interpolating the relative width of a novel stimulus according to visual information kept in spatial working memory. In conclusion, ants can perform conditional discriminations reliably not only when stimuli are simultaneous but also when they are sequential. PMID:26879665

  8. Silver-silver oxide core-shell nanoparticles by femtosecond laser ablation: core and shell sizing by extinction spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Schinca, D C; Scaffardi, L B; Videla, F A; Torchia, G A [Centro de Investigaciones Opticas (CIOp), (CONICET La Plata-CIC), Cno Centenario y 506, 1900 La Plata (Argentina); Moreno, P; Roso, L, E-mail: daniels@ciop.unlp.edu.a [Servicio Laser, Universidad de Salamanca, Plaza de la Merced s/n, 37008, Salamanca (Spain)

    2009-11-07

    The generation of small silver metal nanoparticles (Nps) by ultrashort pulsed laser ablation has been an active area of research in recent years due to their interest in several fields of applied research such as biotechnology and material research, in particular those with sizes smaller than 10 nm. In general, laser ablation tends to produce environmentally clean metal Nps compared with wet chemical methods. However, since silver may be oxidized in the presence of water or ethanol, core-shell silver-silver oxide (Ag-Ag{sub 2}O) Nps can be formed, whose size and thickness must be determined and characterized for functionalization related to future applications. This work analyses the size characteristics of core-shell Ag-Ag{sub 2}O colloid nanostructures (smaller than 10 nm) obtained by femtosecond laser ablation of solid silver targets in different liquid media (water or ethanol) through the study of their optical extinction spectra. A fit of full experimental spectrum using Mie theory allows the determination of core size and shell thickness distributions as a function of fluence. The red-shift of the plasmon peak wavelength with respect to the bare-core peak wavelength at 400 nm, produced by the oxide shell, may be easily measured even for very small thicknesses. It was found that the dominant Ag{sub 2}O effective thickness is inversely proportional to the fluence, reaching a maximum of 0.2 nm for a fluence of 60 J cm{sup -2} and a minimum of 0.04 nm for a fluence of 1000 J cm{sup -2}.

  9. Silver-silver oxide core-shell nanoparticles by femtosecond laser ablation: core and shell sizing by extinction spectroscopy

    International Nuclear Information System (INIS)

    The generation of small silver metal nanoparticles (Nps) by ultrashort pulsed laser ablation has been an active area of research in recent years due to their interest in several fields of applied research such as biotechnology and material research, in particular those with sizes smaller than 10 nm. In general, laser ablation tends to produce environmentally clean metal Nps compared with wet chemical methods. However, since silver may be oxidized in the presence of water or ethanol, core-shell silver-silver oxide (Ag-Ag2O) Nps can be formed, whose size and thickness must be determined and characterized for functionalization related to future applications. This work analyses the size characteristics of core-shell Ag-Ag2O colloid nanostructures (smaller than 10 nm) obtained by femtosecond laser ablation of solid silver targets in different liquid media (water or ethanol) through the study of their optical extinction spectra. A fit of full experimental spectrum using Mie theory allows the determination of core size and shell thickness distributions as a function of fluence. The red-shift of the plasmon peak wavelength with respect to the bare-core peak wavelength at 400 nm, produced by the oxide shell, may be easily measured even for very small thicknesses. It was found that the dominant Ag2O effective thickness is inversely proportional to the fluence, reaching a maximum of 0.2 nm for a fluence of 60 J cm-2 and a minimum of 0.04 nm for a fluence of 1000 J cm-2.

  10. Short and efficient mode-size converter designed by segmented-stepwise method.

    Science.gov (United States)

    Zou, Jinghui; Yu, Yu; Ye, Mengyuan; Liu, Lei; Deng, Shupeng; Xu, Xiaogeng; Zhang, Xinliang

    2014-11-01

    We present an efficient segmented-stepwise method to design a short and low-loss mode-size converter. A silicon-on-insulator platform-based converter with 20 μm length and 95.2% conversion efficiency is acquired by taking only 10 optimization generations using 2D-FDTD method. A 3D-FDTD simulation is performed to verify the calculated results, returning an efficiency of 92.1%. The proposed device can be used to connect a 12-μm-wide waveguide and a 0.5-μm-wide single-mode waveguide, with comparable performance of a regular scheme using 150-μm-long linear taper. For demonstration, the converter was fabricated by electron-beam-lithography and inductively-coupled-plasma etching. A conversion loss of -0.62±0.02  dB at 1550 nm was experimentally measured. PMID:25361332

  11. Configuration-shape-size optimization of space structures by material redistribution

    Science.gov (United States)

    Vandenbelt, D. N.; Crivelli, L. A.; Felippa, C. A.

    1993-01-01

    This project investigates the configuration-shape-size optimization (CSSO) of orbiting and planetary space structures. The project embodies three phases. In the first one the material-removal CSSO method introduced by Kikuchi and Bendsoe (KB) is further developed to gain understanding of finite element homogenization techniques as well as associated constrained optimization algorithms that must carry along a very large number (thousands) of design variables. In the CSSO-KB method an optimal structure is 'carved out' of a design domain initially filled with finite elements, by allowing perforations (microholes) to develop, grow and merge. The second phase involves 'materialization' of space structures from the void, thus reversing the carving process. The third phase involves analysis of these structures for construction and operational constraints, with emphasis in packaging and deployment. The present paper describes progress in selected areas of the first project phase and the start of the second one.

  12. Anisotropic crystallite size analysis of textured nanocrystalline silicon thin films probed by X-ray diffraction

    International Nuclear Information System (INIS)

    A newly developed X-ray technique is used, which is able to quantitatively combine texture, structure, anisotropic crystallite shape and film thickness analyses of nanocrystalline silicon films. The films are grown by reactive magnetron sputtering in a plasma mixture of H2 and Ar onto amorphous SiO2 and single-crystal (100)-Si substrates. Whatever the used substrate, preferred orientations are observed with texture strengths around 2-3 times a random distribution, with a tendency to achieve lower strengths for films grown on SiO2 substrates. As a global trend, anisotropic shapes and textures are correlated with longest crystallite sizes along the direction but absence of oriented crystallites. Cell parameters are systematically observed larger than the value for bulk silicon, by approximately 0.005-0.015 A

  13. Optimal sizing of plug-in fuel cell electric vehicles using models of vehicle performance and system cost

    International Nuclear Information System (INIS)

    Highlights: ► An analytical model for vehicle performance and power-train parameters. ► Quantitative relationships between vehicle performance and power-train parameters. ► Optimal sizing rules that help designing an optimal PEM fuel cell power-train. ► An on-road testing showing the performance of the proposed vehicle. -- Abstract: This paper presents an optimal sizing method for plug-in proton exchange membrane (PEM) fuel cell and lithium-ion battery (LIB) powered city buses. We propose a theoretical model describing the relationship between components’ parameters and vehicle performance. Analysis results show that within the working range of the electric motor, the maximal velocity and driving distance are influenced linearly by the parameters of the components, e.g. fuel cell efficiency, fuel cell output power, stored hydrogen mass, vehicle auxiliary power, battery capacity, and battery average resistance. Moreover, accelerating time is also linearly dependant on the abovementioned parameters, except of those of the battery. Next, we attempt to minimize fixed and operating costs by introducing an optimal sizing problem that uses as constraints the requirements on vehicle performance. By solving this problem, we attain several optimal sizing rules. Finally, we use these rules to design a plug-in PEM fuel cell city bus and present performance results obtained by on-road testing.

  14. BCS-BEC crossover-like phenomena driven by quantum-size effects in quasi-one-dimensional fermionic condensates

    OpenAIRE

    Shanenko, A. A.; Croitoru, M. D.; Vagov, A. V.; Axt, V. M.; Perali, A.; Peeters, F. M.

    2011-01-01

    Quantum confinement is known to influence fermionic condensates, resulting in quantum-size oscillations of superfluid/superconducting properties. Here we show that the impact of quantum-size effects is even more dramatic. Under realistic conditions, a significant phase-space reconfiguration induced by quantum-size effects opens a quasi-molecule channel in the fermionic pairing so that the condensed pairs exhibit features typical of a molecular state. As an illustration we consider a quasi-one...

  15. TPC2 controls pigmentation by regulating melanosome pH and size.

    Science.gov (United States)

    Ambrosio, Andrea L; Boyle, Judith A; Aradi, Al E; Christian, Keith A; Di Pietro, Santiago M

    2016-05-17

    Melanin is responsible for pigmentation of skin and hair and is synthesized in a specialized organelle, the melanosome, in melanocytes. A genome-wide association study revealed that the two pore segment channel 2 (TPCN2) gene is strongly linked to pigmentation variations. TPCN2 encodes the two-pore channel 2 (TPC2) protein, a cation channel. Nevertheless, how TPC2 regulates pigmentation remains unknown. Here, we show that TPC2 is expressed in melanocytes and localizes to the melanosome-limiting membrane and, to a lesser extent, to endolysosomal compartments by confocal fluorescence and immunogold electron microscopy. Immunomagnetic isolation of TPC2-containing organelles confirmed its coresidence with melanosomal markers. TPCN2 knockout by means of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 gene editing elicited a dramatic increase in pigment content in MNT-1 melanocytic cells. This effect was rescued by transient expression of TPC2-GFP. Consistently, siRNA-mediated knockdown of TPC2 also caused a substantial increase in melanin content in both MNT-1 cells and primary human melanocytes. Using a newly developed genetically encoded pH sensor targeted to melanosomes, we determined that the melanosome lumen in TPC2-KO MNT-1 cells and primary melanocytes subjected to TPC2 knockdown is less acidic than in control cells. Fluorescence and electron microscopy analysis revealed that TPC2-KO MNT-1 cells have significantly larger melanosomes than control cells, but the number of organelles is unchanged. TPC2 likely regulates melanosomes pH and size by mediating Ca(2+) release from the organelle, which is decreased in TPC2-KO MNT-1 cells, as determined with the Ca(2+) sensor tyrosinase-GCaMP6. Thus, our data show that TPC2 regulates pigmentation through two fundamental determinants of melanosome function: pH and size. PMID:27140606

  16. Arrays of size and distance controlled platinum nanoparticles fabricated by a colloidal method

    Science.gov (United States)

    Manzke, Achim; Vogel, Nicolas; Weiss, Clemens K.; Ziener, Ulrich; Plettl, Alfred; Landfester, Katharina; Ziemann, Paul

    2011-06-01

    Based on emulsion polymerization in the presence of a Pt complex, polystyrene (PS) particles were prepared exhibiting a well defined average diameter with narrow size-distribution. Furthermore, the colloids contain a controlled concentration of the Pt precursor complex. Optimized coating of Si substrates with such colloids leads to extended areas of hexagonally ordered close-packed PS particles. Subsequent application of plasma etching and annealing steps allows complete removal of the PS carriers and in parallel nucleation and growth of Pt nanoparticles (NPs) which are located at the original center of the PS colloids. In this way, hexagonally arranged spherical Pt NPs are obtained with controlled size and interparticle distances demonstrating variability and precision with so far unknown parameter scalability. This control is demonstrated by the fabrication of Pt NP arrays at a fixed particle distance of 185 nm while systematically varying the diameters between 8 and 15 nm. Further progress could be achieved by seeded emulsion polymerization. Here, Pt loaded PS colloids of 130 nm were used as seeds for a subsequent additional emulsion polymerization, systematically enlarging the diameter of the PS particles. Applying the plasma and annealing steps as above, in this way hexagonally ordered arrays of 9 nm Pt NPs could be obtained at distances up to 260 nm. To demonstrate their stability, such Pt particles were used as etching masks during reactive ion etching thereby transferring their hexagonal pattern into the Si substrate resulting in corresponding arrays of nanopillars.Based on emulsion polymerization in the presence of a Pt complex, polystyrene (PS) particles were prepared exhibiting a well defined average diameter with narrow size-distribution. Furthermore, the colloids contain a controlled concentration of the Pt precursor complex. Optimized coating of Si substrates with such colloids leads to extended areas of hexagonally ordered close-packed PS particles

  17. Gaseous and particulate composition of fresh and aged emissions of diesel, RME and CNG buses using Chemical Ionization Mass Spectrometry

    Science.gov (United States)

    Psichoudaki, Magda; Le Breton, Michael; Hallquist, Mattias; Watne, Ågot; Hallquist, Asa

    2016-04-01

    Urban air pollution is becoming a significant global problem, especially for large cities around the world. Traffic emissions contribute significantly to both elevated particle concentrations and to gaseous pollutants in cities. The latter also have the potential of forming more particulate mass via their photochemical oxidation in the atmosphere. The International Agency for Research on Cancer and the US EPA have characterised diesel exhausts as a likely human carcinogen that can also contribute to other health problems. In order to meet the challenges with increased transportation and enhanced greenhouse gas emissions, the European Union have decided on a 10% substitution of traditional fuels in the road transport sector by alternative fuels (e.g. biodiesel, CNG) before the year 2020. However, it is also important to study the influence of fuel switches on other primary pollutants as well as the potential to form secondary aerosol mass. This work focuses on the characterisation of the chemical composition of the gas and the condensed phase of fresh bus emissions during acceleration, in order to mimic the exhaust plume that humans would inhale under realistic conditions. In addition, photochemical aging of the exhaust emissions was achieved by employing a Potential Aerosol Mass (PAM) flow reactor, allowing the characterization of the composition of the corresponding aged emissions. The PAM reactor uses UV lamps and high concentrations of oxidants (OH radicals and O3) to oxidize the organic species present in the chamber. The oxidation that takes place within the reactor can be equivalent to up to one week of atmospheric oxidation. Preliminary tests showed that the oxidation employed in these measurements corresponded to a range from 4 to 8 days in the atmosphere. During June and July 2015, a total of 29 buses, 5 diesel, 13 CNG and 11 RME (rapeseed methyl ester), were tested in two different locations with limited influence from other types of emissions and traffic

  18. Pancreatic cancer accompanied by a moderate-sized pseudocyst with extrapancreatic growth

    International Nuclear Information System (INIS)

    Pancreatic cancer accompanied by a moderate-sized pseudocyst with extrapancreatic growth is extremely rare. Diagnosis of pancreatic cancer on preoperative imaging is difficult when the pancreatic parenchyma is compressed by a pseudocyst and becomes unclear. Despite advances in imaging techniques, accurate preoperative diagnosis of cystic lesions of the pancreas remains difficult. In this case, it was challenging to diagnose pancreatic cancer preoperatively as we could not accurately assess the pancreatic parenchyma, which had been compressed by a moderate-sized cystic lesion with extrapancreatic growth. A 63-year-old woman underwent investigations for epigastric abdominal pain. She had no history of pancreatitis. Although we suspected pancreatic ductal carcinoma with a pancreatic cyst, there was no mass lesion or low-density area suggestive of pancreatic cancer. We did not immediately suspect pancreatic cancer, as development of a moderate-sized cyst with extrapancreatic growth is extremely rare and known tumor markers were not elevated. Therefore, we initially suspected that a massive benign cyst (mucinous cyst neoplasm, serous cyst neoplasm, or intraductal papillary mucinous neoplasm) resulted in stenosis of the main pancreatic duct. We were unable to reach a definitive diagnosis prior to the operation. We had planned a pancreaticoduodenectomy to reach a definitive diagnosis. However, we could not remove the tumor because of significant invasion of the surrounding tissue (portal vein, superior mesenteric vein, etc.). The fluid content of the cyst was serous, and aspiration cytology from the pancreatic cyst was Class III (no malignancy), but the surrounding white connective tissue samples were positive for pancreatic adenocarcinoma on pathological examination during surgery. We repeated imaging (CT, MRI, endoscopic ultrasound, etc.) postoperatively, but there were neither mass lesions nor a low-density area suggestive of pancreatic cancer. In retrospect, we think

  19. The Amplification of the Critical Temperature by Quantum Size Effects In a Superlattice of Quantum Wires

    International Nuclear Information System (INIS)

    Here we report experimental evidence that the high Tc superconductivity in a cuprate perovskite occurs in a superlattice of quantum wires. The structure of the high Tc superconducting CuO2 plane in Bi2Sr2CaCu2O8+y (Bi2212) at the mesoscopic level (10-100 A) has been determined. It is decorated by a plurality of parallel superconducting stripes of width L=14± 1 A defined by the domain walls formed by stripes of width W=11+1 A characterized by a 0.17 A shorter Cu-O (apical) distance and a large tilting angle θ =12±4degree of the distorted square pyramids. We show that this particular heterostructure provides the physical mechanism raising Tc from the low temperature range Tc2 plane by a factor ∼10 is realized by 1) tuning the Fermi level near the bottom of the second ubband of the stripes, with ky=2π/L, formed by the quantum size effect and 2) by forming a superlattice of wires with domain walls of width W of the order of the superconducting coherence length ξ0. (author)

  20. Duodenal myotomy blocks reduction of meal size and prolongation of intermeal interval by cholecystokinin.

    Science.gov (United States)

    Lateef, Dalya M; Washington, Martha C; Raboin, Shannon J; Roberson, Allison E; Mansour, Mahmoud M; Williams, Carol S; Sayegh, Ayman I

    2012-02-01

    We have shown that vagotomy (VGX) attenuates the reduction of meal size (MS) produced by cholecystokinin (CCK) -8 and -33 and that celiaco-mesenteric ganglionectomy (CMGX) attenuates the prolongation of the intermeal interval (IMI) produced by CCK-33. Here, we report the following novel data. First, by determining the distribution of CCK(1) receptor messenger RNA, which mediates reduction of MS and prolongation of IMI by CCK, in seven regions of the gastrointestinal tract in the adult rat we found that the duodenum contains the highest concentration of this receptor in the gut. Second, based on the previous finding we performed a unique surgical technique known as duodenal myotomy (MYO), which severs all the nerves of the gut wall in the duodenum including vagus, splanchnic and enteric nerves. Third, we determined MS and IMI in duodenal MYO rats in responses to endogenous CCK-58 released by the non-nutrient, trypsin inhibitor, camostat and CCK-8 to test the possibility that the duodenum is the site of action for reduction of MS and prolongation of IMI. We found that, similar to the previous work reported by using CCK-8 and MS, duodenal MYO also blocked reduction of MS by camostat. Forth, duodenal MYO blocked prolongation of IMI by camostat. As such, our current results suggest that the duodenum is the gut site that communicates both feeding signals of endogenous CCK, MS and IMI, with the brain through vagal and splanchnic afferents. PMID:22047890

  1. The swelling behavior of montmorillonite as affected by the grain size by in situ X-ray diffraction experiments

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In many existing researches, the swelling behavior and impermeability of smectitic engineered barrier materials in disposal facilities of radioactive waste was investigated. In the RWMC-project, the effect of smectite content on the mechanical and hydraulic behavior of smectitic materials is investigated and modeled to introduce into THMC analysis. However, since smectite is a natural resource, physical and chemical properties are different with places of production. In order to model the swelling behavior and impermeability of smectitic materials, not only the smectite content but also layer charge and crystal size will be the primary factors. In addition, smectite types and impurity minerals contents or soluble salts affect bentonite characteristic, as well. In this research, in order to focus on the effect of grain size of smectite, the swelling behavior of smectitic materials which are the same place of production but are different grain size were investigated. The smectitic material used in this study was Kunipia-F (Kunimine Industry Co. Ltd., Japan), which is from the Tukinuno Mine, Yamagata prefecture, Japan, and is purified montmorillonite produced by hydraulic elutriation. It is considered that the montmorillonite, Kunipia-F, has large crystal size, and for example Kunipia-F is able to make a sheet when drying weak solution. The grain size was conditioned by jet mill pulverizer. The pulverizing was conducted by making each other collide with high speed. The grain size of the intact and pulverized samples was measured by using of the laser scattering particle distribution analyzer and SEM. The swelling behavior was measured by in situ X-ray diffraction using of a sample chamber which can control the temperature and humidity precisely. The result of the laser scattering analysis denoted that the pulverized sample fined down expressly. The difference of the crystal aspect ratio of the pre- and post

  2. Development of UT procedure for SCC crack depth sizing by phased array UT in Ni-based alloy weld

    International Nuclear Information System (INIS)

    The advanced phased array UT technique for SCC crack depth sizing in Ni-based alloy weld was developed. In previous study, authors proposed to the UT procedure for defect depth sizing by phased array UT in the inside inspection. The UT procedure was applied to the defect depth sizing in Ni-based alloy weld specimen with EDM notches. From these results, superior performance for defect depth sizing by phased array UT technique was shown. However, it is not clarified the performance of SCC crack depth sizing. And then, it is not established the fabrication method of Ni-based alloy weld specimen with artificial SCC crack. In this paper, the investigated results of fabrication method of Ni-based alloy weld specimen with axial SCC crack are shown. Furthermore, phased array UT technique for crack depth sizing was applied to the Ni-based alloy weld specimen with axial SCC crack. From the experimental results, good accuracy of SCC crack depth sizing by phased array UT in the inside inspection was shown. Therefore, it was clarified the effectiveness of the UT procedure for defect depth sizing in Ni-based alloy weld. Furthermore, main factors of crack depth sizing error were investigated, and then countermeasure for the decrease of those errors was also investigated. (author)

  3. Analysis of size-fractionated coal combustion aerosols by PIXE and other analytical techniques

    International Nuclear Information System (INIS)

    Particle-induced X-ray emission (PIXE) analysis, instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) were used to study the chemical composition of size-fractionated in-stack fly-ash particles emitted during coal combustion. The samples were collected before the electrostatic precipitator at a gas temperature of 120deg C during the combustion of Venezuelan coal in a 81 MW capacity circulating fluidized bed boiler. The sampling device consisted of a Berner low pressure impactor, which was operated with a cyclone precutter. The Nuclepore polycarbonate foils, which were used as collection surfaces in the low pressure impactor, were analyzed by the three techniques, and the results of common elements were critically compared. The PIXE results were systematically lower than the INAA data, and the percentage difference appeared to be stage-dependent, but virtually independent upon the element. The discrepancies are most likely due to bounce-off effects, particle reentrainment and other sampling artifacts, which may make that a fraction of the aerosol particles is deposited on the impaction foils outside the section analyzed by PIXE. However, by restoring to a 'mixed internal standard' approach, accurate PIXE data are obtained. Also in the comparison between the ICP-MS and the INAA data significant discrepancies were observed. These are most likely due to incomplete dissolution of the particulate material, and in particular of the alumino-silicate fly-ash matrix, during the acid digestion sample preparation step for ICP-MS. It is suggested that a comparison between ICP-MS data of acid digested samples and INAA can advantageously be used to provide speciation information on the various elements. Selected examples of size distributions are presented and briefly discussed. (orig.)

  4. Urban heat island by means of city clusters: a statistical assessment of size influence and seasonality

    Science.gov (United States)

    Zhou, Bin; Rybski, Diego; Kropp, Jürgen P.

    2014-05-01

    In the last decades, influence factors of the Urban Heat Island (UHI) effect have been intensively investigated and further broadened through a variety of studies around the world. Briefly, compared to non-built surroundings, built-up areas of cities differ considerably in albedo, thermal capacity, roughness, etc. which can significantly modify the surface energy budget and make downtown areas of cities hotter than their vicinities. Most previous studies were built upon a limited number of cities, and suffered from inconsistency and instability with regard to the urban-rural definition, which hinders the inter-comparison between results. To overcome this limitation in the number of considered cities, we perform a systematic study of all cities in Europe to assess the Surface Urban Heat Island (SUHI) intensity by means of land surface temperature data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. After defining cities as spatial clusters of urban land cover based on CORINE data, we determine a boundary around the urban cluster of approximately equal area to the cluster area. SUHI intensity is thus defined as the difference between the mean temperature in the cluster and that of the surroundings. We investigate the relationships of the SUHI intensity, respectively with the cluster size and with the temperature of the surroundings. Our results show that in Europe, the SUHI intensity in summer has a strong correlation with the cluster size, which can be well fitted by an empirical sigmoid model. Furthermore, we find a pronounced seasonality of the SUHI intensity for individual clusters in the form of hysteresis-like curves. Characterizing the shape by means of Fourier series approximation and consequential work of clustering, we identify apparent regional patterns which suggest a climatological basis for the heterogeneity of UHI.

  5. SSZ-13 Crystallization by Particle Attachment and Deterministic Pathways to Crystal Size Control.

    Science.gov (United States)

    Kumar, Manjesh; Luo, Helen; Román-Leshkov, Yuriy; Rimer, Jeffrey D

    2015-10-14

    Many synthetic and natural crystalline materials are either known or postulated to grow via nonclassical pathways involving the initial self-assembly of precursors that serve as putative growth units for crystallization. Elucidating the pathway(s) by which precursors attach to crystal surfaces and structurally rearrange (postattachment) to incorporate into the underlying crystalline lattice is an active and expanding area of research comprising many unanswered fundamental questions. Here, we examine the crystallization of SSZ-13, which is an aluminosilicate zeolite that possesses exceptional physicochemical properties for applications in separations and catalysis (e.g., methanol upgrading to chemicals and the environmental remediation of NO(x)). We show that SSZ-13 grows by two concerted mechanisms: nonclassical growth involving the attachment of amorphous aluminosilicate particles to crystal surfaces and classical layer-by-layer growth via the incorporation of molecules to advancing steps on the crystal surface. A facile, commercially viable method of tailoring SSZ-13 crystal size and morphology is introduced wherein growth modifiers are used to mediate precursor aggregation and attachment to crystal surfaces. We demonstrate that small quantities of polymers can be used to tune crystal size over 3 orders of magnitude (0.1-20 μm), alter crystal shape, and introduce mesoporosity. Given the ubiquitous presence of amorphous precursors in a wide variety of microporous crystals, insight of the SSZ-13 growth mechanism may prove to be broadly applicable to other materials. Moreover, the ability to selectively tailor the physical properties of SSZ-13 crystals through molecular design offers new routes to optimize their performance in a wide range of commercial applications. PMID:26376337

  6. High-throughput characterization of virus-like particles by interlaced size-exclusion chromatography.

    Science.gov (United States)

    Ladd Effio, Christopher; Oelmeier, Stefan A; Hubbuch, Jürgen

    2016-03-01

    The development and manufacturing of safe and effective vaccines relies essentially on the availability of robust and precise analytical techniques. Virus-like particles (VLPs) have emerged as an important and valuable class of vaccines for the containment of infectious diseases. VLPs are produced by recombinant protein expression followed by purification procedures to minimize the levels of process- and product-related impurities. The control of these impurities is necessary during process development and manufacturing. Especially monitoring of the VLP size distribution is important for the characterization of the final vaccine product. Currently used methods require long analysis times and tailor-made assays. In this work, we present a size-exclusion ultra-high performance liquid chromatography (SE-UHPLC) method to characterize VLPs and quantify aggregates within 3.1min per sample applying interlaced injections. Four analytical SEC columns were evaluated for the analysis of human B19 parvo-VLPs and murine polyoma-VLPs. The optimized method was successfully used for the characterization of five recombinant protein-based VLPs including human papillomavirus (HPV) VLPs, human enterovirus 71 (EV71) VLPs, and chimeric hepatitis B core antigen (HBcAg) VLPs pointing out the generic applicability of the assay. Measurements were supported by transmission electron microscopy and dynamic light scattering. It was demonstrated that the iSE-UHPLC method provides a rapid, precise and robust tool for the characterization of VLPs. Two case studies on purification tools for VLP aggregates and storage conditions of HPV VLPs highlight the relevance of the analytical method for high-throughput process development and process monitoring of virus-like particles. PMID:26845741

  7. Atypical BCS-BEC crossover induced by quantum-size effects

    OpenAIRE

    Shanenko, A. A.; Croitoru, M. D.; Vagov, A. V.; Axt, V. M.; Perali, A.; Peeters, F. M.

    2012-01-01

    Quantum-size oscillations of the basic physical characteristics of a confined fermionic condensate are a well-known phenomenon. Its conventional understanding is based on the single-particle physics, whereby the oscillations follow the size-dependent changes in the single-particle density of states. Here we present a study of a cigar-shaped ultracold superfluid Fermi gas, which demonstrates an important many-body aspect of the quantum-size effects, overlooked previously. The many-body physics...

  8. The effects upon particle size and morphology of thermoelectric nanopowders prepared by high intensity ultrasonic milling

    International Nuclear Information System (INIS)

    A high intensity ultrasound generator was used to prepare thermoelectric powders from a crystalline material source. Significant morphological change was observed, including a reduction in the size distributions of the resulting particles, the larger of which developed a smoother appearance. Data indicates that a lower size limit is obtainable which may, through variation of the experimental conditions, offer a tuneable size distribution. A system has been devised to facilitate the processing of material powders. (papers)

  9. Genome size of human oral Treponema species by pulsed-field gel electrophoresis.

    Science.gov (United States)

    Correia, F F; Plummer, A R; Paster, B J; Dewhirst, F E

    2004-04-01

    The genome sizes of seven strains of oral treponemes were determined using pulsed-field gel electrophoresis (PFGE). These strains represent members from six of the currently known cultivable oral treponeme groups. The PFGE fragments were digitally recorded and then quantitated using GIMP v 1.2, an image manipulation program. The results show that the six oral treponeme genomes are comparable in size, ranging from approximately 2.2 to 2.5 Mbp. The genome sizes of these strains are 20-25% smaller than Treponema denticola strains, which have genome sizes of approximately 2.8-3.0 Mbp. PMID:14871355

  10. SIZE REDUCTION OF ELECTROSTATIC PRECIPITATOR CHAMBER BY MODIFICATION OF GAS FLOW DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    Beata Sładkowska-Rybka

    2014-10-01

    Full Text Available Electrostatic precipitators (ESP are one of the most effective devices for particulate emission control, removing from the exhaust gases even 99,9 % of dust particles. The collection efficiency of the ESP depends on a number of factors: mechanical design and electrical operating parameters, physical and chemical properties of cleaned gas, characteristic of dust particles suspended in the gas. Among the most important factors affecting the ESP effectiveness, the velocity and the distribution of gas flow in the ESP chamber should be also indicated. Significant increase in ESP efficiency is possible thanks to the application of Skewed Gas Flow Technology (SGFT. In this paper the computer simulations results are shown. Authors investigated the possibility of ESP chamber size reduction by modification of gas flow distribution.

  11. Extraction and separation of polysaccharides from Laminaria japonica by size-exclusion chromatography.

    Science.gov (United States)

    Zhang, Heng; Row, Kyung Ho

    2015-04-01

    A large number of studies have suggested that polysaccharides, such as fucoidan and laminarin, in various seaweeds have significant biological properties. A different distribution of molecular weights is a prominent sign of many polysaccharides. Therefore, a simple, fast and reliable high-performance size-exclusion chromatography (HPSEC) method was proposed to separate fucoidan and laminarin from Laminaria japonica. After evaluating the different separation conditions for HPSEC, such as the type of mobile phase and flow rate, an acid extraction method was established and optimized by a systematic investigation of the influencing factors. Under the optimal conditions, 169.2 and 383.8 mg g(-1) of fucoidan and laminarin, respectively, were extracted. This method is suitable for the extraction and separation of polysaccharides with good reproducibility of the retention time, acceptable linearity, small relative standard deviation and low detection limits. PMID:25013027

  12. Interdisciplinary Construction and Implementation of a Human Sized Humanoid Robot by Master Students

    Science.gov (United States)

    Helbo, Jan; Svendsen, Mads Sølver

    With limited funding it seemed a very good idea to encourage Master Students to design and construct their own human sized biped robot. Because this task is huge and very interdisciplinary different areas of expertise were covered by students from different departments who in turn took over results from former students. In the last three years three student groups from Department of Mechanical Engineering and Electronic Systems have been working on the project. The robot AAU-BOT1 has been designed, manufactured, assembled, instrumented and walking should be possible in the near future. The Project Organized Problem Based Learning method implemented at Aalborg University is one of the reasons why supervisors give Master Students such a challenge.

  13. Enhancement of mechanical properties and grain size refinement of commercial purity aluminum 1050 processed by ECAP

    International Nuclear Information System (INIS)

    Equal channel angle pressing (ECAP) of commercial purity aluminum (1050) was conducted using two processing routes, namely routes BC and C. The variation of hardness and yield strength with number of pressings was documented up to eight passes. Compression tests were used to evaluate post ECAP deformation response. Electron back scattered diffraction (EBSD) was used to obtain statistical information on the microstructure developed (cell size and misorientation angle) during ECAP and after combining ECAP with simple compression. The present results showed that first ECAP pass has resulted in enhancement of mechanical properties more than three times over the annealed condition. Further ECAP processing has resulted in slight improvement. The true stress-strain curve for ECAPed specimens tested under compression showed short transient region of large strain hardening rate followed by perfectly plastic behavior and strain softening. This behavior was discussed in details based on the microstructure study

  14. Investment in different sized SMRs: Economic evaluation of stochastic scenarios by INCAS code

    International Nuclear Information System (INIS)

    Small Modular LWR concepts are being developed and proposed to investors worldwide. They capitalize on operating track record of GEN II LWR, while introducing innovative design enhancements allowed by smaller size and additional benefits from the higher degree of modularization and from deployment of multiple units on the same site. (i.e. 'Economy of Multiple' paradigm) Nevertheless Small Modular Reactors pay for a dis-economy of scale that represents a relevant penalty on a capital intensive investment. Investors in the nuclear power generation industry face a very high financial risk, due to high capital commitment and exceptionally long pay-back time. Investment risk arise from uncertainty that affects scenario conditions over such a long time horizon. Risk aversion is increased by current adverse conditions of financial markets and general economic downturn, as is the case nowadays. This work investigates both the investment profitability and risk of alternative investments in a single Large Reactor or in multiple SMR of different sizes drawing information from project's Internal Rate of Return stochastic distribution. multiple SMR deployment on a single site with total power installed, equivalent to a single LR. Uncertain scenario conditions and stochastic input assumptions are included in the analysis, representing investment uncertainty and risk. Results show that, despite the combination of much larger number of stochastic variables in SMR fleets, uncertainty of project profitability is not increased, as compared to LR: SMR have features able to smooth IRR variance and control investment risk. Despite dis-economy of scale, SMR represent a limited capital commitment and a scalable investment option that meet investors' interest, even in developed and mature markets, that are traditional marketplace for LR. (authors)

  15. Size-dependent impairment of cognition in mice caused by the injection of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu-Shiun; Hong, Meng-Yeng; Huang, G Steve [Institute of Nanotechnology, Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan (China); Hung, Yao-Ching [Section of Gynecologic Oncology, Department of Obstetrics and Gynecology, China Medical University and Hospital, 91 Hsueh Shih Road, Taichung 404, Taiwan (China); Lin, Li-Wei [School of Chinese Medicine for Post-Baccalaureate, I-Shou University, 8 Yida Road, Yanchao Township, Kaohsiung Country 82445, Taiwan (China); Liau, Ian, E-mail: gstevehuang@mail.nctu.edu.tw [Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan (China)

    2010-12-03

    We explored the size-dependent impairment of cognition in mice caused by the injection of gold nanoparticles (GNPs). GNPs of 17 and 37 nm in diameter were injected intraperitoneally into BALB/c mice at doses ranging from 0.5 to 14.6 mg kg{sup -1}. ICP-MS was performed on brain tissue collected 1, 14 and 21 days after the injection. A passive-avoidance test was performed on day 21. Monoamine levels were determined on day 21. The microscopic distribution of GNPs in the hippocampus was examined using coherent anti-Stokes Raman scattering (CARS) microscopy and transmission electron microscopy (TEM). The results indicated that 17 nm GNPs passed through the blood-brain barrier more rapidly than 37 nm GNPs. Treatment with 17 nm GNPs decreased the latency time, which was comparable to the effect of scopolamine treatment, while 37 nm GNPs showed no significant effect. Dopamine levels and serotonin levels in the brain were significantly altered by the injection of 17 and 37 nm GNPs. GNPs affected dopaminergic and serotonergic neurons. CARS microscopy indicated that 17 nm GNPs entered the Cornu Ammonis (CA) region of the hippocampus, while 37 nm GNPs were excluded from the CA region. TEM verified the presence of 17 nm GNPs in the cytoplasm of pyramidal cells. In this study, we showed that the ability of GNPs to damage cognition in mice was size-dependent and associated with the ability of the particles to invade the hippocampus. The dosage and duration of the treatment should be taken into account if GNPs are used in the future as vehicles to carry therapeutic agents into the brain.

  16. Size-dependent impairment of cognition in mice caused by the injection of gold nanoparticles

    International Nuclear Information System (INIS)

    We explored the size-dependent impairment of cognition in mice caused by the injection of gold nanoparticles (GNPs). GNPs of 17 and 37 nm in diameter were injected intraperitoneally into BALB/c mice at doses ranging from 0.5 to 14.6 mg kg-1. ICP-MS was performed on brain tissue collected 1, 14 and 21 days after the injection. A passive-avoidance test was performed on day 21. Monoamine levels were determined on day 21. The microscopic distribution of GNPs in the hippocampus was examined using coherent anti-Stokes Raman scattering (CARS) microscopy and transmission electron microscopy (TEM). The results indicated that 17 nm GNPs passed through the blood-brain barrier more rapidly than 37 nm GNPs. Treatment with 17 nm GNPs decreased the latency time, which was comparable to the effect of scopolamine treatment, while 37 nm GNPs showed no significant effect. Dopamine levels and serotonin levels in the brain were significantly altered by the injection of 17 and 37 nm GNPs. GNPs affected dopaminergic and serotonergic neurons. CARS microscopy indicated that 17 nm GNPs entered the Cornu Ammonis (CA) region of the hippocampus, while 37 nm GNPs were excluded from the CA region. TEM verified the presence of 17 nm GNPs in the cytoplasm of pyramidal cells. In this study, we showed that the ability of GNPs to damage cognition in mice was size-dependent and associated with the ability of the particles to invade the hippocampus. The dosage and duration of the treatment should be taken into account if GNPs are used in the future as vehicles to carry therapeutic agents into the brain.

  17. Onset of size independent cationic exchange in nano-sized CoFe{sub 2}O{sub 4} induced by electronic excitation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Hemaunt [Department of Physics, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand 263145 (India); Singh, Jitendra Pal, E-mail: jitendra_singh2029@rediffmail.com [Advanced Analysis Canter, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Srivastava, R.C.; Negi, P.; Agrawal, H.M. [Department of Physics, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand 263145 (India); Asokan, Kandasami [Materials Science Division, Inter University Accelerator Centre, New Delhi 110067 (India); Won, Sung Ok [Advanced Analysis Canter, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Chae, Keun Hwa, E-mail: khchae@kist.re.kr [Advanced Analysis Canter, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

    2015-10-05

    Highlights: • Electronic excitation induced crystalline order in CoFe{sub 2}O{sub 4}. • No change of metallic valence state under dense electronic excitation. • Size independent control of cations in CoFe{sub 2}O{sub 4}. - Abstract: Present work investigates electronic excitation induced cationic exchange phenomena in nano-sized cobalt ferrites using Mössabaur and X-ray absorption spectroscopies. The electronic excitations were produced by irradiation of 100 MeV O{sup +7} at different fluences ranging from 1 × 10{sup 11} to 1 × 10{sup 14} ions/cm{sup 2}. Cubic spinel phase of cobalt ferrite remains preserved after irradiation. However, attributes of crystalline disorder were observed in irradiated materials. Crystallite size remain almost same for pristine and irradiated materials. X-ray absorption fine structure measurements show the preservation of valence state and spin state of metal ions under intense electronic excitation. These measurements also envisage bond breaking process induced by the electronic excitation. Mössbauer spectroscopic measurements also corroborate with the fine structure measurements that the valence state of Fe remains same after irradiation. Paramagnetic doublet which presents in the Mössabaur spectrum of pristine material disappears after irradiation, showing the evolution of irradiation induced magnetic ordering. Fe{sup 3+} ion increases with irradiation at octahedral site of spinel lattice. Magnetization of the material slightly increases after irradiation at the fluence of 5 × 10{sup 13} and 1 × 10{sup 14} ions/cm{sup 2}.

  18. Determination of pore size distributions in capillary-channeled polymer fiber stationary phases by inverse size-exclusion chromatography and implications for fast protein separations.

    Science.gov (United States)

    Wang, Zhengxin; Marcus, R Kenneth

    2014-07-18

    Capillary-channeled polymer (C-CP) fibers have been utilized as liquid chromatography stationary phases, primarily for biomacromolecule separations on the analytical and preparative scales. The collinear packing of the eight-channeled C-CP fibers provides for very efficient flow, allowing operation at high linear velocity (u>100mm s(-1)) and low backpressure (advantage of these fluid transport properties, there must not be mass transfer limitations as would be imposed by having an appreciably porous phase, wherein solute diffusion limits the overall mass transport rates. To better understand the physical nano-/micro- structure of C-CP fibers, inverse size exclusion chromatography (iSEC) has been employed to determine the pore size distribution (PSD) within C-CP fibers. A diversity of test species (from metal ions to large proteins) was used as probes under non-retaining conditions to obtain a response curve reflecting the apparent partition coefficient (Kd) versus hydrodynamic radii (rm). A mean pore radius (rp) of 4.2nm with standard deviation (sp) of ±1.1nm was calculated by fitting the Kd versus rm data to model equations with a Gaussian pore size distribution, and a pore radius of 4.0±0.1nm was calculated based on a log-normal distribution. The derived mean pore radius is much smaller than traditional support materials, with the standard deviation showing a relatively uniform pore distribution. van Deemter plots were analyzed to provide practical confirmation of the structural implications. Large molecules (e.g., proteins) that are fully excluded from pores have no significant C-terms in the van Deemter plots whereas small molecules that can access the pore volumes display appreciable C-terms, as expected. Fitting of retention data to the Knox equation suggests that the columns operate with a characteristic particle diameter (dp) of ∼53μm. PMID:24877979

  19. Interrill erosion, runoff and sediment size distribution as affected by slope steepness and antecedent moisture content

    Directory of Open Access Journals (Sweden)

    M. B. Defersha

    2010-08-01

    Full Text Available Soil erosion is a two-phase process consisting of the detachment of individual particles and their transport by erosive agents such as flowing water. The rate at which erosion occurs depends upon the individual as well as interactive effects of different parameters responsible for soil erosion. The study discusses results of a laboratory analysis and evaluates the effect of slope steepness and antecedent moisture content on sediment yield (wash and runoff rate. Interrill sediment yield, splash detachment, runoff, and sediment size distribution were measured in laboratory erosion pans under simulated total duration of 90 min. Rainfall intensity at 120 mm/hr, 70 mm/hr, and 55 mm/hr were applied sequentially at 9, 25, and 45% slope steepness for three soils (Alemaya Black soil, Regosols, and Cambisols varied from clay to sandy clay loam in texture with wet and dry antecedent water contents. As slope steepness increased from 9 to 25% splash increased for five treatments and decreased for the remaining treatment; washed sediment increased for all treatments. As slope increased from 25 to 45% splash decreased for five treatments but increased for one treatment, and washed sediment increased for three treatments but decreased for the other three treatments. Pre-wetting decreased splash detachment for all soil treatments and rate of reduction was high for the highly aggregated soil, Alemaya Black soil and low for the less aggregated soil Regosols. Splash sediment and sediment yield was not correlated. Change in splash with increase in slope steepness was also not correlated with change in sediment yield. Change in runoff rate with increase in slope steepness was correlated (r=0.66 with change in sediment yield. For Alemaya Black soil and Regosols, splashed sediment size distribution was correlated with washed sediment size distribution. Interrill erosion models that include runoff and rainfall intensity parameters were a better fit for these data

  20. Ductility Enhancement of Molybdenum Phase by Nano-sized Oxide Dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Bruce

    2008-07-18

    The objective of this research is to understand and to remedy the impurity effects for room-temperature ductility enhancement of molybdenum (Mo) based alloys by the inclusion of nano-sized metal oxide dispersions. This research combines theoretical, computational, and experimental efforts. The results will help to formulate systematic strategies in searching for better composed Mo-based alloys with optimal mechanical properties. For this project, majority of the research effort was directed to atomistic modeling to identify the mechanisms responsible for the oxygen embrittling and ductility enhancement based on fundamental electronic structure analysis. Through first principles molecular dynamics simulations, it was found that the embrittling impurity species were attracted to the metal oxide interface, consistent with previous experiments. Further investigation on the electronic structures reveals that the presence of embrittling species degrades the quality of the metallic chemical bonds in the hosting matrix in a number of ways, the latter providing the source of ductility. For example, the spatial flexibility of the bonds is reduced, and localization of the impurity states occurs to pin the dislocation flow. Rice’s criterion has been invoked to explain the connections of electronic structure and mechanical properties. It was also found that when impurity species become attracted to the metal oxide interface, some of the detrimental effects are alleviated, thus explaining the observed ductility enhancement effects. These understandings help to develop predictive capabilities to facilitate the design and optimization of Mo and other high temperature alloys (e.g. ODS alloys) for fossil energy materials applications. Based on the theoretical and computational studies, the experimental work includes the preparation of Mo powders mixed with candidate nano-sized metal oxides, which were then vacuum hot-pressed to make the Mo alloys. Several powder mixing methods