WorldWideScience

Sample records for bituminous aggregates

  1. Identification of aggregates for Tennessee bituminous surface courses

    Sauter, Heather Jean

    Tennessee road construction is a major venue for federal and state spending. Tax dollars each year go to the maintenance and construction of roads. One aspect of highway construction that affects the public is the safety of its state roads. There are many factors that affect the safety of a given road. One factor that was focused on in this research was the polish resistance capabilities of aggregates. Several pre-evaluation methods have been used in the laboratory to predict what will happen in a field situation. A new pre-evaluation method was invented that utilized AASHTO T 304 procedure upscaled to accommodate surface bituminous aggregates. This new method, called the Tennessee Terminal Textural Condition Method (T3CM), was approved by Tennessee Department of Transportation to be used as a pre-evaluation method on bituminous surface courses. It was proven to be operator insensitive, repeatable, and an accurate indication of particle shape and texture. Further research was needed to correlate pre-evaluation methods to the current field method, ASTM E 274-85 Locked Wheel Skid Trailer. In this research, twenty-five in-place bituminous projects and eight source evaluations were investigated. The information gathered would further validate the T3CM and find the pre-evaluation method that best predicted the field method. In addition, new sources of aggregates for bituminous surface courses were revealed. The results of this research have shown T3CM to be highly repeatable with an overall coefficient of variation of 0.26% for an eight sample repeatability test. It was the best correlated pre-evaluation method with the locked wheel skid trailer method giving an R2 value of 0.3946 and a Pearson coefficient of 0.710. Being able to predict field performance of aggregates prior to construction is a powerful tool capable of saving time, money, labor, and possibly lives.

  2. Study on Plastic Coated Overburnt Brick Aggregate as an Alternative Material for Bituminous Road Construction

    Dipankar Sarkar

    2016-01-01

    Full Text Available There are different places in India where natural stone aggregates are not available for constructional work. Plastic coated OBBA can solve the problem of shortage of stone aggregate to some extent. The engineers are always encouraged to use locally available materials. The present investigation is carried out to evaluate the plastic coated OBBA as an alternative material for bituminous road construction. Shredded waste plastics are mixed with OBBA in different percentages as 0.38, 0.42, 0.46, 0.50, 0.54, and 0.60 of the weight of brick aggregates. Marshall Method of mix design is carried out to find the optimum bitumen content of such bituminous concrete mix prepared by plastic coated OBBA. Bulk density, Marshall Stability, flow, Marshall Quotient, ITS, TSR, stripping, fatigue life, and deformations have been determined accordingly. Marshall Stability value of 0.54 percent of plastic mix is comparatively higher than the other mixes except 0.60 percent of plastic mix. Test results are within the prescribed limit for 0.54 percent of plastic mix. There is a significant reduction in rutting characteristics of the same plastic mix. The fatigue life of the mix is also significantly higher. Thus plastic coated OBBA is found suitable in construction of bituminous concrete road.

  3. Mechanical properties of hot bituminous mixes manufactured with recycled aggregate of Silestone® waste

    Rubio, M. C.

    2011-03-01

    Full Text Available This article presents the results of a research project which analyzes the viability of incorporating waste material from decorative quartz solid surfacing in the manufacture of hot bituminous mixes. For this purpose, various bituminous mixes were manufactured with waste aggregate in different percentage. A set of tests were carried out that permitted the characterization of the mechanical behavior of these mixes. The results of these tests were similar to the results obtained when conventional mixes made from virgin quarry aggregate were tested. The results for moisture sensitivity as well as for wheel track rutting on mixes showed the optimal performance of this waste material even under very demanding traffic conditions. Laboratory studies showed that the use of this waste material in the manufacture of bituminous mixes is technically viable and can provide high-quality recycled aggregates at a very low cost, which can be used in the pavement of road.

    Este artículo muestra los resultados de un proyecto de investigación que tiene por objeto analizar la viabilidad de incorporación de residuos procedentes de piedra decorativa en la fabricación de mezclas bituminosas en caliente. Para ello se fabricaron mezclas con áridos reciclados de residuos procedentes de piedra decorativa en distintos porcentajes, realizando un conjunto de ensayos que posibilitaron caracterizar el comportamiento mecánico de dichas mezclas. Los resultados obtenidos fueron similares a los de las mezclas convencionales fabricadas con áridos vírgenes procedentes de cantera. Los valores de resistencia conservada ante la acción del agua y deformación en pista, pusieron de manifiesto la aptitud del residuo incluso ante las condiciones de tráfico más exigentes. Los trabajos realizados en el laboratorio indican que la utilización del residuo en la fabricación de mezclas bituminosas es técnicamente viable, pudiendo obtenerse áridos reciclados de gran calidad y

  4. Waste to Wealth; The Utilization of Scrap Tyre as Aggregate in Bituminous Mixes for Road Construction

    Oba, A. L.,

    2015-11-01

    Full Text Available The problem associated with solid waste management is on the increase both in the industries, urban cities and in the rural areas. In the United States of America, Asia and Europe, there are over hundreds of waste to wealth combustion plants from where solid wastes are incinerated. In Nigeria, amidst the increasing importation of vehicle tyre such plants are scarcely in existence to enhance generation of revenue from waste through the extraction of raw material for the production of light weight aggregates, printing ink, paints, shoe polish, dry cell and battery heads. This research paper seeks to utilize vehicle scrap tyre (VST as aggregates in asphaltic mixture by adopting the dry process to evaluate the effect of rubber-bitumen interaction on asphaltic concrete properties; laboratory investigation using 4.75mm, 2.36mm and 0.600mm chunk tyre particle size modified asphalt mixture containing 2%, 4%, 6%, 8% and 10% scrap tyre and 0% tyre content as control mixture. The mixtures were subjected to Marshall Tests where the stability, flow, percentage air void, unit weight, void mineral aggregate, height of specimen and specific gravity were determined. The results obtained shows that as tyre percentage increase the stability, unit weight and specific gravity value decreases. On the other hand, as the tyre content increases, the flow and height of specimen increases while as the tyre content increases the percentage air void and VMA increased for 4.75mm Tyre Particle Size (TPS and 2.36mm TPS while for 0.600mm TPS, reverse is the case. In summary and in comparism with standard specification for road construction material, the Marshall tests conducted on the tyre modified specimens remained intact and by interpretation; material possessing such property indicates good impact resistance when use as surface course in flexible pavement. Conclusively, the use of 10% 4.75mm, 4% 2.36mm or 4% 0.600mm TPS by weight of aggregate in asphaltic concrete is

  5. A preliminary investigation into the physical and chemical properties of biomass ashes used as aggregate fillers for bituminous mixtures.

    Melotti, Roberto; Santagata, Ezio; Bassani, Marco; Salvo, Milena; Rizzo, Stefano

    2013-09-01

    Fly and bottom ashes are the main by-products arising from the combustion of solid biomass. Since the production of energy from this source is increasing, the processing and disposal of the resulting ashes has become an environmental and economic issue. Such ashes are of interest as a construction material because they are composed of very fine particles similar to fillers normally employed in bituminous and cementitious mixtures. This research investigates the potential use of ash from biomass as filler in bituminous mixtures. The morphological, physical and chemical characteristics of 21 different ashes and two traditional fillers (calcium carbonate and "recovered" plant filler) were evaluated and discussed. Leaching tests, performed in order to quantify the release of pollutants, revealed that five ashes do not comply with the Italian environmental re-use limits. Experimental results show a wide range of values for almost all the investigated properties and a low correlation with biomass type in terms of origin and chemical composition. Furthermore, sieving and milling processes were found to improve the properties of the raw material in terms of grading and sample porosity. The effectiveness of these treatments and the low content of organic matter and harmful fines suggest that most of the biomass ashes investigated may be regarded as potential replacements for natural filler in bituminous mixtures. PMID:23790672

  6. Bituminization plant Jaslovske Bohunice

    In this leaflet the principle of the bituminization plant for radioactive concentrate (the intermediate liquid radioactive waste generated during the NPP A1, V-1, V-2 operations) solidification used in the Bohunice Radwaste Treatment Centre (BSC RAO) is presented

  7. Cold bituminous mixes

    Delak, Boštjan

    2012-01-01

    Asphalt mix (short also asphalt) can be obtained from nature (natural asphalt) or produced technically (artificial asphalt), i. e. as a mix of bituminous binder, stone grain, and other additives that improve the asphalt properties. The beginnings of the use of asphalt can be traced from 6,000 to 4,000 BC since people back then knew some materials that contained bitumen as a binder. A more frequent use of the natural asphalt, however, starts around 3,000 BC. Different peoples used it primar...

  8. Effect of Cement on Properties of Over-Burnt Brick Bituminous Concrete Mixes

    Sarkar, Dipankar; Pal, Manish

    2016-06-01

    The present investigation is carried out to propose the use of cement coated over burnt brick aggregate in the preparation of bituminous concrete mix. The effect of cement on various mechanical properties such as Marshall stability, flow, Marshall quotient (stability to flow ratio), indirect tensile strength, stripping, rutting and fatigue life of bituminous concrete overlay has been evaluated. In this study, different cement percentages such as 2, 3, 4 and 5 % by weight of aggregate have been mixed with Over Burnt Brick Aggregate (OBBA). The laboratory results indicate that bituminous concrete prepared by 4 % cement coated OBBA gives the highest Marshall stability. The bituminous concrete mix with 4 % cement shows considerable improvement in various mechanical properties of the mix compared to the plain OBBA concrete mix.

  9. Skid resistance of bituminous surfaces in Ohio

    Colony, D. C.

    1984-03-01

    Statistical studies of skid number (SN) on the state highway system in Ohio reveal apparently systematic variations in distributions of SN among the twelve districts in the state. These variations appear to be significantly related to traffic and to geological characteristics of a given district. Regression calculations using traffic index, a function of ADT and age of the pavement surface in months, show a high correlation with SN, although standard errors of estimate were too large to make the equations useful for predicting SN from traffic variables. Similar results were obtained by elating SN to physiographic features in the state. Pavement surface type (bituminous or pcc) and coarse aggregate type (limestone, gravel or slag) are significantly related to SN.

  10. Leachability of bituminized radioactive waste. Literature survey

    Bituminized radioactive waste that will be returned from COGEMA, France is planned to be disposed of in deep geologic repository in Japan. Data on leachability of radionuclides from bituminized waste are required for the performance assessment of the disposal. We made a literature survey on bitumen and bituminized radioactive waste, placing emphasis on leach tests and leach data in terms of geologic disposal. This survey revealed that reliable leach data on transuranium elements and data obtained under reducing conditions that is characteristic to deep underground are lacking. (author). 64 refs

  11. Bituminous reference document: synthesis of knowledge on the long time behavior of bituminous packages

    This document is a synthesis of the knowledge acquired at the CEA on the behavior of bituminous packages. In this framework, the CEA studied bituminous packages in generic conditions of a package lifetime. The main factors, the evolution mechanisms and influential parameters have been determined and quantitative s simulation have been developed. After a description of the main initial bituminous packages characterizations, the evolutions in saturated and un-saturated environment are exposed. (A.L.B.)

  12. 30 CFR 716.4 - Special bituminous coal mines.

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Special bituminous coal mines. 716.4 Section... INTERIOR INITIAL PROGRAM REGULATIONS SPECIAL PERFORMANCE STANDARDS § 716.4 Special bituminous coal mines. (a) Definition. Special bituminous coal surface mines as used in this section means those...

  13. The microstructure of petroleum vacuum residue films for bituminous concrete: a microscopy approach.

    Sourty, E D; Tamminga, A Y; Michels, M A J; Vellinga, W-P; Meijer, H E H

    2011-02-01

    Selected carbon-rich refinery residues ('binders') mixed with mineral particles can form composite materials ('bituminous concrete') with bulk mechanical properties comparable to those of cement concrete. The microstructural mechanism underlying the remarkable composite properties has been related to the appearance of a rigid percolating network consisting of asphaltenes and mineral particles [Wilbrink M. et al. (2005) Rigidity percolation in dispersions with a structured visco-elastic matrix. Phys. Rev. E71, 031402]. In this paper, we explore the microstructure of thin binder films of varying thickness with a number of microscopic characterization techniques, and attempt to relate the observed microstructure to the distinctive mechanical behaviour. Two binders, only one of which has been proven to be suitable for bituminous concrete were investigated, and their microstructure compared. Both binders show the formation of asphaltene aggregates. The binder suitable for bituminous concrete is distinguished by the fact that the asphaltenes show a stronger tendency towards such aggregation, due to a higher concentration and less stabilization in the maltene phase. They also show a clear affinity to other species (such as waxes) and may act as nucleation sites for crystals and aggregates of those species. PMID:21118207

  14. 8th RILEM International Symposium on Testing and Characterization of Sustainable and Innovative Bituminous Materials

    Partl, Manfred

    2016-01-01

    This work presents the results of RILEM TC 237-SIB (Testing and characterization of sustainable innovative bituminous materials and systems). The papers have been selected for publication after a rigorous peer review process and will be an invaluable source to outline and clarify the main directions of present and future research and standardization for bituminous materials and pavements. The following topics are covered: - Characterization of binder-aggregate interaction - Innovative testing of bituminous binders, additives and modifiers - Durability and aging of asphalt pavements - Mixture design and compaction analysis - Environmentally sustainable materials and technologies - Advances in laboratory characterization of bituminous materials - Modeling of road materials and pavement performance prediction - Field measurement and in-situ characterization - Innovative materials for reinforcement and interlayer systems - Cracking and damage characterization of asphalt pavements - Rec...

  15. Evaluating Self Healing Capability of Bituminous Mastics

    Qiu, J.; Ven, M. van de; Wu, S.; Yu, J.; Molenaar, A.

    2012-01-01

    The self-healing capability of bituminous materials has been known for many years. Researches were mostly focused on the self healing behaviour during load repetitions. The tests are either time consuming and/or complex. In this paper, a simple self healing test procedure is presented combining the fracture-healing-re-fracture test (FHR) with morphological observations. A fast displacement speed loading was applied first to produce a flat open crack with a crack width of 100–200 μm. Then the ...

  16. A process for the bituminization of radioactive wastes

    A process is described for the incorporation of sodium nitrate solutions in bitumen, with a view to the bituminization of radioactive wastes. This process has involved the development of a chemical process and its technological application. A double jacket reactor equipped with an anchor-type stirrer has been built. Sodium nitrate (NaNO3) solutions with sodium hydroxide (NaOH) are fed into the reactor simultaneously with a bitumen emulsion while heated oil is circulated through the double jacket. After all the water has evaporated, the mixture is ''simmered'' at 170/180 deg C for up to 5 hours in order to get a homogeneous product which will be suitable for final storage. The product contains small salt crystals (10/50 μm) and has high viscosity (200/2000 poise at 160 deg C and 12 rpm), so that the possibility of sedimentation is eliminated. In comparative experiments with molten bitumen, large salt aggregates, inhomogeneously distributed, make the product unsuitable. It has been found that NaOH is responsible for the polimerization of the bitumen, which raises its viscosity. The degree of polimerization depends on the NaOH concentration and ''simmering'' time and temperature. NaOH is added to NaNO3 in order to raise the mixture's viscosity and thereby prevent sedimentation

  17. Crumb Rubber in cold recycled bituminous mixes

    Dondi, Giulio; Tataranni, Piergiorgio; Pettinari, Matteo;

    2014-01-01

    . Cold recycling is, among the recycling techniques, certainly the most studied and developed: it allows the recovering of bituminous material from an existing pavement without the addition of heat, whilst ensuring the creation of high quality bound base layers. A wide range of materials have been tested...... together with Reclaimed Asphalt Pavement (RAP) and, consequently, there is a large number of variables that can be considered in the mix-design process of new eco-friendly Cold Recycled Mixes. In particular, the present research involves the use of Crumb Rubber within a mixture containing 100% Reclaimed...... Asphalt Pavement, cold recycled with bitumen emulsion and cement. Two different Crumb Rubbers were adopted: one from the ambient production method, and one produced with the cryogenic process. The goal of this research project was to analyze and evaluate the different physical and mechanical...

  18. Radon concentration measurements in bituminous coal mines

    Radon measurements were carried out in Kozlu, Karadon and Uezuelmez underground coal mines of Zonguldak bituminous coal basin in Turkey. Passive-time integrating method, which is the most widely used technique for the measurement of radon concentration in air, was applied by using nuclear etched track detectors (CR-39) in the study area. The radon concentration measurements were performed on a total of 42 points in those three mines. The annual exposure, the annual effective dose and lifetime fatality risk, which are the important parameters for the health of workers, were estimated based on chronic occupational exposure to the radon gas, which is calculated using UNCEAR-2000 and ICRP-65 models. The radon concentrations at several coal production faces are higher than the action level of 1000 Bq m-3. It is suggested that the ventilation rates should be rearranged to reduce the radon concentration. (authors)

  19. Recycling of polyethylene terephthalate (PET plastic bottle wastes in bituminous asphaltic concrete

    Adebayo Olatunbosun Sojobi

    2016-12-01

    Full Text Available This research sheds light on the concept of eco-friendly road construction which comprises eco-design, eco-extraction, eco-manufacturing, eco-construction, eco-rehabilitation, eco-maintenance, eco-demolition, and socioeconomic empowerment. It also revealed the challenges being faced in its adoption and the benefits derivable from its application. Furthermore, the effects of recycling PET plastic bottle wastes produced in North Central Nigeria in bituminous asphaltic concrete (BAC used in flexible pavement construction were also evaluated. The mix design consists of 60/70 penetration-grade asphaltic concrete (5%, 68% coarse aggregate, 6% fine aggregate, and 21% filler using the dry process at 170°C. The optimum bitumen content (OBC for conventional BAC was obtained as 4% by weight of total aggregates and filler. Polymer-coated aggregate (PCA-modified BAC seems preferable because it has the potential to utilize more plastic wastes with a higher optimum plastic content (OPC of 16.7% by weight of total aggregates and filler compared to that of 9% by weight of OBC achieved by PMB-BAC. For both PMB- and PCA-modified BAC, an increase in air void, void in mineral aggregate, and Marshall stability were observed. Eco-friendly road construction which recycles PET wastes should be encouraged by government considering its potential environmental and economic benefits.

  20. Development of non-standard equipment of bituminization line

    A brief description is presented of some components of the bituminization line developed at the Research Institute of Chemical Installations in Brno. The film rotor evaporator has an evaporation area of 2 m2. The mixing tank is the main technological assembly for processing loose materials, i.e., sorbents and fly ash which it mixes with melted bitumen. The screw conveyor with a three-way valve is designed for batching the dried radioactive sorbent and fly ash into mixing tanks. Attention is also devoted to certain systems of measurement and control of the bituminization line, namely to measurement of the level of the bituminization product, the flow rate of bituminization emulsion and the water-sorbent mixture and to the diagnostics of failure and accident conditions of the film rotor evaporator. (Z.M.)

  1. Bituminous and asphaltic membranes for radioactive waste repositories on land

    The aim of the study has been to identify, within generic designs for waste facilities, areas where bituminous materials might be incorporated as a barrier. The report is presented in three sections: Part I - The properties of bitumen are described, with particular reference to the long-term behaviour of the material. The durability of bitumen is discussed, including aspects such as ageing, microbial degradation, chemical resistance and radiation resistance. Part II -The use of bituminous materials in hydraulic engineering is outlined. Much of this section of the report concentrates on the use of bituminous materials in embankment dams and reservoir construction. A review of material technology and construction techniques is presented and a detailed assessment made of the performance of the materials in service. Part III - Generic trench type radioactive waste repository designs incorporating bituminous materials are presented. Material and construction specifications for the designs are detailed, and a performance assessment presented. (author)

  2. Long-term properties of bituminized waste products

    This study is a survey of the factors of importance for long term behaviour of bituminized ion exchange resins. Phenomena occurring in bituminized waste products affected by the treatment, storage and disposal are identified. Test methods have been developed for characterizing product properties, which are important for the long-term behaviour. The long-term properties of bituminized ion-exchange resins are studied in a repository environment with access of water equilibrated with concrete. In these circumstances the most important properties are ralated to the interactions of bituminized waste with the surrounding barriers. The most important phenomena are water uptake due to rehydration of the resins and subsequent swelling of the product. (author)

  3. Long-term properties of bituminized waste products

    This study is a survey of the factors of importance for the long term behaviour of bituminized ion exchange resins. Phenomena occurring in bituminized waste products affected by the treatment, storage and disposal are identified. Test methods have been developed for characterizing product properties, which are important for the long-term behaviour. The long-term properties of bituminized ion-exchange resins are studied in a repository environment with access of water equilibrated with concrete. In these circumstances the most important properties are related to the interactions of bituminized waste with the surrounding barriers. The most important phenomena are water uptake due to rehydration of the resins and subsequent swelling of the product

  4. Effects of bituminous layer as backfill material on mechanical behavior in tunnel model

    Moriyoshi, Akihiro; Takano, Shin-ei; Urata, Hiroyuki; Suzuki, Tetsuya; Yoshida, Takaki

    2001-01-01

    This paper describes the effects of bituminous material as a backfill material on mechanical behavior in model tunnel in laboratory. It is known that load spreading and relaxation of bituminous material are good properties. Then if we use bituminous material as a backfill material of tunnel, the tunnel will have waterproof, good load spreading property. We used new bituminous material (Aquaphalt) which can solidify in water. We conducted relaxation test in tension for new bituminous mat...

  5. The bituminous sands : a Canadian mirage?

    Rousse, D.R. [Quebec Univ., Chicoutimi, PQ (Canada). Dept. des Sciences Appliquees; Nasr, G.J. [Lebanese Univ., Roumieh (Lebanon). Faculty of Engineering; Turcotte, S.F. [Quebec Univ., Montreal, PQ (Canada). Centre d' Etudes Internationales et Mondialisation; Salah, N.B. [Ecole Superieure des Sciences et Techniques De Tunis, Tunis (Tunisia). LMMP

    2009-07-01

    This paper examined the controversy about the potential role of a significant increase in Canadian oil sands production in order to bridge the upcoming gap between the world's increasing energy demand and the total recoverable oil supply. The paper presented the actual potential of different scenarios and considered the prediction cost forecasts. A brief overview of environmental impacts and the real return on investments were also provided. Environmental impacts that were considered included land degradation; water contamination; ecosystem damage; and air pollution. Nuclear energy was also presented as a possible solution. The paper demonstrated that even in a very optimistic scenario, Canada's oil sands accelerated production has a negligible effect on the aforementioned gap, has a considerable impact on environment that has yet to be accounted for. Energy ratios that were presented included energy return on energy investment; energy available on energy used; and energy payback. It was concluded that enhanced recovery techniques are clearly needed for future sustainable exploitation of these bituminous sands. 32 refs., 1 fig.

  6. Bituminization of low- and intermediate-level radioactive concentrates

    The results and experiences are summed up from the research and development of the technology of bituminization of low- and intermediate-level radioactive concentrates generated in the operation of nuclear power plants with WWER-440 reactors. The experiments took place on a pilot plant bituminization line with various model solutions at an evaporator capacity of 70, 100 and 140 litres per hour. The composition of the solutions changed in dependence on the knowledge of the composition of actual concentrates in the V-1 nuclear power plant at Jaslovske Bohunice. The following factors were studied in the concentrate: the effect of its pH, its borate content and content of metal carbonates, the content of organic acid salts, the content of detergents, etc., on the process of bituminization. Physico-chemical conditions are described under which the operation of the evaporator was fail-safe and filling of the bituminization product with salts homogeneous. A low water content of up to 1% was achieved. The properties of the bituminization product were negatively affected by a high level of heavy metal oxides, surfactants, oxalates and citrates. In order to improve the properties of the product it will be necessary to replace bitumen emulsion Silembit-60 used as reinforcement matrix, by a different type of bitumen. (Z.M.)

  7. Measurement of heat generation from simulated bituminized product

    The fire and explosion incident occurred at Bituminization Demonstration Facility of PNC Tokai Works on March 11, 1997. In order to ascertain the cause of incident, the investigation has been pushed forward. For the investigation, we prepared simulated bituminized product of measurement of heat generation in low temperature region less than 200degC. We used calvet Calorimeter MS80 for the heat generation measurement. Result of measurement, we were able to catch the feeble heat generation from bituminized product. The maximum calorific value that was able to detect it in isothermal measurement was approximately 1 mW/g in 160degC. It was approximately 2 mW/g in 200degC. And, as the another measurement, the measurement condition went heat rate by 0.01degC/minute, the highest temperature 190degC. As a result, the maximum generation of heat value that was able to detect it was approximately 0.5 mW/g. I changed simulated bituminized products and measured these. A difference of condition is salt particle size, salt content rate (45%, 60%), addition of the simulated precipitate. But there was not a difference in the generation of heat characteristic detected. (author)

  8. Unexpectedly high uptake of palladium by bituminous coals

    Lakatos, J. [Research Lab. for Mining Chemistry, Hungarian Academy of Sciences, Miskolc-Egyetemvaros (Hungary); Brown, S.D.; Snape, C.E. [Univ. of Strathclyde, Dept. of Pure and Applied Chemistry, Glasgow (United Kingdom)

    1997-12-31

    The uptake of palladium as a conversion catalyst onto coals of different rank was investigated. Palladium fixation occurs by a different mode to that for alkaline earth and first row transition metals. Therefore, the dispersion of relatively high concentration of palladium by an ion sorption process is even possible for bituminous coals. (orig.)

  9. Performance of PAHs emission from bituminous coal combustion

    严建华; 尤孝方; 李晓东; 倪明江; 尹雪峰; 岑可法

    2004-01-01

    Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion.

  10. Amenability of Muzret bituminous coal to oil agglomeration

    Sahinoglu, E.; Uslu, T. [Karadeniz Technical University, Department of Mining Engineering, 61080 Trabzon (Turkey)

    2008-12-15

    Laboratory scale agglomeration tests were undertaken to investigate the amenability of Muzret (Yusufeli-Artvin) bituminous coal to oil agglomeration. Kerosene was extensively used as oil in the tests. In addition, fuel oil, diesel oil, and hazelnut oil were also used in order to determine the effect of oil type. The effects of the parameters including coal content, kerosene content, agglomeration time, coal particle size, pH, oil type, and agitation rate, on the combustible matter recovery, ash reduction and pyritic sulphur reduction, were investigated. It was found that Muzret bituminous coal could be readily cleaned by oil agglomeration with substantial reductions in ash and pyritic sulphur content. Maximum combustible matter recovery, ash reduction and pyritic sulphur reduction were achieved to be 85.54%, 59.98%, and 85.17%, respectively. (author)

  11. Wetting of bituminized ion-exchangers under simulated repository conditions

    According to the present plans the spent nuclear fuel from four Finnish nuclear power units will be transferred after interim storage to the final disposal site where it will be encapsulated and disposed of in a final repository constructed into the bedrock at a depth of 500 meters. Low and medium level waste generated at nuclear power plants will be finally disposed of in caverns constructed in the bedrock at the power plant site. The safety of the final disposal is based on a multibarrier concept and the degree of safety is estimated by using predictive models. The properties of the waste form are taken into account in the design of the repository construction. Bitumen has been chosen as an immobilisation agent for the wet wastes at Olkiluoto Power Plant, where two BWR units, TVO 1 and TVO 2, have separate bituminization facilities designed by Asea-Atom. Properties of bituminized spent ion-exchange resins from Olkiluoto power plant have been studied by VTT Chemical Technology since the late 70's. These studies have concentrated mainly on determining the long-term behaviour of the bituminization product under the repository conditions. Current interest lies on wetted product as a diffusion barrier. For this purpose a microscopic method for the visualisation of the structure of the wetted product has been developed. The equilibration of the samples in simulated concrete groundwater is currently going on at a temperature of 5-8 deg. C. Preliminary results are presented in this paper. Diffusion experiments have been planned for the further characterising of the wetted product as a release barrier for radionuclides including modelling. (author)

  12. Sorption of aqueous phosphorus onto bituminous and lignitous coal ashes

    Aiming at the development of a phosphorus removal technology for waste water, phosphate (PO43-) retention behavior of bituminous and lignitous coal ashes was investigated using a batch reactor. Ash samples, including fresh and weathered fly and bottom ashes, were studied for their sorption isotherms and reversibility. Fly ashes had a much higher phosphate retention capacity (4000-30,000 mg P/kg) than bottom ashes (15-600 mg P/kg). Lignitous coal ashes were more capable of retaining phosphate than bituminous coal ashes. The retention process was largely irreversible, and the irreversibility increased with the increase in the retention capacity. Weathering enlarged the retention capacity of the bituminous bottom ash, but substantially lowered that of the fly ash, likely due to the difference in the weather-induced changes between the fly and bottom ashes. Sorption isotherms of fly ashes were found to be adequately represented by the Langmuir model while those of bottom ashes fitted better to the Freundlich model. Concentrations of Ca2+ and PO43- in the aqueous phase were measured at the end of sorption and desorption experiments, and were compared with solubilities of three calcium phosphate minerals. The aqueous solutions were saturated or super-saturated with respect to tricalcium phosphate (Ca3(PO4)2) and hydroxyapatite (Ca5(PO4)3OH), and slightly under-saturated with respect to amorphous calcium phosphate. It is concluded that precipitation of calcium phosphate is the predominant mechanism for phosphate retention by coal ash under the conditions studied. There is a strong and positive correlation between alkalinity and phosphate sorption capacity. Consequently, acid neutralization capacity (ANC) can be used as an indicator of phosphate sorption capacity of coal ashes

  13. Sorption of aqueous phosphorus onto bituminous and lignitous coal ashes

    Yan Jinying; Kirk, Donald W. [Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5 (Canada); Jia, Charles Q. [Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5 (Canada)], E-mail: cqjia@chem-eng.toronto.edu; Liu Xinan [College of Chemical Engineering, Chongqing University, Chongqing (China)

    2007-09-05

    Aiming at the development of a phosphorus removal technology for waste water, phosphate (PO{sub 4}{sup 3-}) retention behavior of bituminous and lignitous coal ashes was investigated using a batch reactor. Ash samples, including fresh and weathered fly and bottom ashes, were studied for their sorption isotherms and reversibility. Fly ashes had a much higher phosphate retention capacity (4000-30,000 mg P/kg) than bottom ashes (15-600 mg P/kg). Lignitous coal ashes were more capable of retaining phosphate than bituminous coal ashes. The retention process was largely irreversible, and the irreversibility increased with the increase in the retention capacity. Weathering enlarged the retention capacity of the bituminous bottom ash, but substantially lowered that of the fly ash, likely due to the difference in the weather-induced changes between the fly and bottom ashes. Sorption isotherms of fly ashes were found to be adequately represented by the Langmuir model while those of bottom ashes fitted better to the Freundlich model. Concentrations of Ca{sup 2+} and PO{sub 4}{sup 3-} in the aqueous phase were measured at the end of sorption and desorption experiments, and were compared with solubilities of three calcium phosphate minerals. The aqueous solutions were saturated or super-saturated with respect to tricalcium phosphate (Ca{sub 3}(PO{sub 4}){sub 2}) and hydroxyapatite (Ca{sub 5}(PO{sub 4}){sub 3}OH), and slightly under-saturated with respect to amorphous calcium phosphate. It is concluded that precipitation of calcium phosphate is the predominant mechanism for phosphate retention by coal ash under the conditions studied. There is a strong and positive correlation between alkalinity and phosphate sorption capacity. Consequently, acid neutralization capacity (ANC) can be used as an indicator of phosphate sorption capacity of coal ashes.

  14. Low-level radioactive wastes bituminization - ion exchange resins

    The present work describes the research and development of low level radioactive waste treatment by bituminization process in Nuclear Technology Development Centre (CDTN). Low level radioactive solid waste was simulated by mixed ion exchange resin. Cation exchange and anion resin were loaded with lithium and boric acid respectively and were incorporated in bitumen of suitable rheological properties. The simulated solid wastes incorporated in bitumen were 30 to 46 weight %. The rheological properties of waste product bitumen-mixed resin have been reported. The waste product with bitumen V-65 showed best physical and rheological properties and grave lowest leaching rates of boron and lithium. (author)

  15. Retardation of the spontaneous ignition of bituminous coal

    Dong, X.; Drysdale, D. [University of Edinburgh, Edinburgh (United Kingdom). Department of Civil Engineering and Building Science

    1995-12-31

    The effect of five retardants on a bituminous coal has been investigated in a temperature-controlled oven. The activation energy of oxidation in the coal inhibited by one of the retardants increases by up to 20kJ/mol, in comparison to that of the coal wetted with water. The factors affecting inhibition are considered. A kinetic interpretation of the retardation mechanism is proposed, and the possibility of using the most effective retarder in practice is discussed. 12 refs., 1 fig., 2 tabs.

  16. JUDGMENT AGGREGATION AND PREFERENCE AGGREGATION

    Joanna Ochremiak

    2011-01-01

    In the paper we present an introduction to the theory of judgment aggregation and discuss its relation to the theory of preference aggregation. We compare the formal model of judgment aggregation, based on logic, with the formal model of preference aggregation. Finally, we present a theorem in judgmentaggregation which is an exact analogue of Arrow's theorem for strict preferences.

  17. Waste to Wealth; The Utilization of Scrap Tyre as Aggregate in Bituminous Mixes for Road Construction

    Oba, A. L.,; Onungwe, I.,

    2015-01-01

    The problem associated with solid waste management is on the increase both in the industries, urban cities and in the rural areas. In the United States of America, Asia and Europe, there are over hundreds of waste to wealth combustion plants from where solid wastes are incinerated. In Nigeria, amidst the increasing importation of vehicle tyre such plants are scarcely in existence to enhance generation of revenue from waste through the extraction of raw material for the production ...

  18. DURABILITY OF ASPHALT CONCRETE MIXTURES USING DOLOMITE AGGREGATES

    Imad Al-Shalout

    2015-12-01

    Full Text Available This study deals with the durability of asphalt concrete, including the effects of different gradations, compaction temperatures and immersion time on the durability potential of mixtures. The specific objectives of this study are: to investigate the effect of compaction temperature on the mechanical properties of asphalt concrete mixtures; investigate the effect of bitumen content and different aggregate gradations on the durability potential of bituminous mixtures.

  19. Behaviour of bituminized ion-exchangers under repository conditions

    This is a final report containing all the research activities and results from the period 13 July 1997-28 February 2001. The purpose of the research was to study the ageing behaviour of bituminized ion-exchanger product under simulated repository conditions. The chosen temperature in this study was 5-8 deg. C and the equilibration solution used was artificial concrete water to simulate the conditions in the final disposal. The aim was to study the properties of wetted product as a release barrier for such important waste nuclides as Sr-90 and Cs-137, which are normal constituents of the bituminized ion-exchangers. All the nine exchanged waters were analysed by ion chromatography (IC) including the follow-up of the water absorption of the samples. All the samples, which were picked up for microscopic examination, have also been analysed. A saturation-elution test was performed with one diffusion sample using tritium (H-3) as a tracer. The results have been presented and further modelling will be performed later. Further two diffusion samples were tested using H-3, Na-22 and Cl-36 as radioactive tracers. The equilibration solution was artificial concrete ground water spiked with H-3 and Na-22 and in the other case with H-3 and Cl-36. Tritium was an internal reference when comparing the results of the equilibration behaviour of Na-22 and Cl-36. From the radioactive input cells samples were taken as a function of time to monitor the equilibration process. Elution of the samples and modelling of the results will be performed later. Na-22 and Cl-36 were chosen to demonstrate the behaviour of a simple anion and cation. Diffusion tests with important waste nuclides Sr-90 and Cs-137 have been scheduled to years 2001-2002. The aim of the performed research project was to study the barrier properties of the bituminized product. The measured parameters and modelling of the results will reflect the behaviour of the wetted product as a part of the multibarrier system providing

  20. Environmental problems caused by bituminous schist and possible solutions

    Schist, as a disposal of mine, has harmful effects on environment. however, several manners can be utilized to prevent the environmental destruction as well as an economical benefit is gained. In this study, environmental problems caused by bituminous schist and other disposals have been investigated on a specific lignite coal mine where schist is disposed as waste material. Pollution and damage on land and in water sources around the coal district and the villages have been observed, recorded and several solutions to environmental problems have been proposed. Discussed proposals will not only solve the environmental pollution problem but also provide waste management facility. Industrial structure of the district enables such a disposal to be used as an economical raw material. Besides, general effects of the coal mine and the power plant nearby have been discussed from environmental point of view, too. 7 refs

  1. Study of thermal reactivity during bituminization of radioactive waste

    This work deals with the study of chemical reactions and phases transitions which can occur between magnesium nitrate, sodium nitrate, cobalt sulphur product, and nickel potassium ferrocyanide, when they are heated together during bituminization process of nuclear waste. The applied methodology associates a few techniques: temperature, enthalpy, and kinetics of reaction are determined by calorimetry, reaction products are characterised by chemical analyses, mass spectrometry and XRD analysis. Three fields of temperature and energy are observed in function of composition (one compound or a mixture of compounds). The study of reactions between NaNO3 and cobalt sulphur product shows that the presence of water has got an effect on reaction temperature. The study of Mg(NO3)2, 6 H2O and CoS shows an overlapping of different signals, and that the reaction rate is very slow (a few hours). (author)

  2. Rational Aggregation

    Bruce Chapman

    2002-01-01

    In two recent papers, Christian List and Philip Pettit have argued that there is a problem in the aggregation of reasoned judgements that is akin to the aggregation of the preference problem in social choice theory.1 Indeed, List and Pettit prove a new general impossibility theorem for the aggregation of judgements, and provide a propositional interpretation of the social choice problem that suggests it is a special case of their impossibility result.2 Specifically, they show that no judgemen...

  3. Weighted aggregation

    Feiveson, A. H. (Principal Investigator)

    1979-01-01

    The use of a weighted aggregation technique to improve the precision of the overall LACIE estimate is considered. The manner in which a weighted aggregation technique is implemented given a set of weights is described. The problem of variance estimation is discussed and the question of how to obtain the weights in an operational environment is addressed.

  4. State of the art report on bituminized waste forms of radioactive wastes

    In this report, research and development results on the bituminization of radioactive wastes are closely reviewed, especially those regarding waste treatment technologies, waste solidifying procedures and the characteristics of asphalt and solidified forms. A new concept of the bituminization method is suggested in this report which can improve the characteristics of solidified forms. Stable solid forms with high leach resistance, high thermal resistance and good compression strength were produced by the suggested bituminization method, in which spent polyethylene from agricultural farms was added. This report can help further research and development of improved bituminized forms of radioactive wastes that will maintain long term stabilities in disposal sites. (author). 59 refs., 19 tabs., 18 figs

  5. State of the art report on bituminized waste forms of radioactive wastes

    Kim, Tae Kook; Shon, Jong Sik; Kim, Kil Jeong; Lee, Kang Moo; Jung, In Ha

    1998-03-01

    In this report, research and development results on the bituminization of radioactive wastes are closely reviewed, especially those regarding waste treatment technologies, waste solidifying procedures and the characteristics of asphalt and solidified forms. A new concept of the bituminization method is suggested in this report which can improve the characteristics of solidified forms. Stable solid forms with high leach resistance, high thermal resistance and good compression strength were produced by the suggested bituminization method, in which spent polyethylene from agricultural farms was added. This report can help further research and development of improved bituminized forms of radioactive wastes that will maintain long term stabilities in disposal sites. (author). 59 refs., 19 tabs., 18 figs

  6. Synthesis document on the long time behavior of packages: operational document ''bituminous'' 2204

    This document is realized in the framework of the law of 1991 on the radioactive wastes management. The 2004 synthesis document on long time behavior of bituminous sludges packages is constituted by two documents, the reference document and the operational document. This paper presents the operational model describing the water alteration of the packages and the associated radioelements release, as the gas term source and the swelling associated to the self-irradiation and the bituminous radiolysis. (A.L.B.)

  7. Polygenic formation model of the planet's bituminous belts

    Dmitrievsky, A. N.; Balanyuk, I. E.

    2011-05-01

    In recent years, much attention has been paid to nontraditional hydrocarbon sources. Today the portion of nontraditional gas in the world extraction is 15% or 450 billion cubic meters, which hat makes up the volume of total gas exports from Russia. As is known, the easy-prospecting oil has been already found. The innovative technologies in geophysics, drilling, and excavation and the increased extraction coefficient expect further development and industrial compliance with these requirements. Based on calculations, the world oil reserves are now one trillion of stock tank barrels and one trillion barrels have been already extracted. The evergrowing demand for energy gives rise to the necessity of searching for and extracting more oil resources, and both these aspects are unique problems. The search for profitable petroleum deposits has become more and more difficult even in the leading companies. The increment of the world resources is a key vital question; therefore, the elaboration of criteria for the discovery of nontraditional deposits take on special significance in the economic respect. The authors are working out a conception that will be a guideline for future finding of the richest oil deposits in active geodynamic zones. For the first time, we suggest the polygenic formation model of the planet's bituminous belts.

  8. The hydrogasification of lignite and sub-bituminous coals

    Bhatt, B.; Fallon, P. T.; Steinberg, M.

    1981-02-01

    A North Dakota lignite and a New Mexico sub-bituminous coal have been hydrogenated at up to 900°C and 2500 psi hydrogen pressure. Yields of gaseous hydrocarbons and aromatic liquids have been studied as a function of temperature, pressure, residence time, feed rates and H2/coal ratio. Coal feed rates in excess of 10 lb/hr have been achieved in the 1 in. I. D.×8 ft reactor and methane concentration as high as 55% have been observed. A four-step reaction model was developed for the production and decomposition of the hydrocarbon products. A single object function formulated from the weighted errors for the four dependent process, variables, CH4, C2H6, BTX, and oil yields, was minimized using a program containing three independent iterative techniques. The results of the nonlinear regression analysis for lignite show that a first-order chemical reaction model with respect to C conversion satisfactorily describes the dilute phase hydrogenation. The activation energy for the initial products formation was estimated to be 42,700 cal/gmole and the power of hydrogen partial pressure was found to be +0.14. The overall correlation coefficient was 0.83. The mechanism, the rate expressions, and the design curves developed can be used for scale-up and reactor design.

  9. Gasification of high ash, high ash fusion temperature bituminous coals

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  10. Fuel properties of bituminous coal and pyrolytic oil mixture

    Hamdan, Hazlin; Sharuddin, Munawar Zaman; Daud, Ahmad Rafizan Mohamad; Syed-Hassan, Syed Shatir A.

    2014-10-01

    Investigation on the thermal decomposition kinetics of coal-biooil slurry (CBS) fuel prepared at different ratios (100:0,70:30,60:40,0:100) was conducted using a Thermogravimetric Analyzer (TGA). The materials consisted of Clermont bituminous coal (Australia) and bio-oil (also known as pyrolytic oil) from the source of Empty Fruit Bunch (EFB) that was thermally converted by means of pyrolysis. Thermal decomposition of CBS fuel was performed in an inert atmosphere (50mL/min nitrogen) under non-isothermal conditions from room temperature to 1000°C at heating rate of 10°C/min. The apparent activation energy (Ea.) and pre-exponential factor (A) were calculated from the experimental results by using an Arrhenius-type kinetic model which first-order decomposition reaction was assumed. All kinetic parameters were tabulated based on the TG data obtained from the experiment. It was found that, the CBS fuel has higher reactivity than Clermont coal fuel during pyrolysis process, as the addition of pyrolytic oil will reduce the Ea values of the fuel. The thermal profiles of the mixtures showed potential trends that followed the characteristics of an ideal slurry fuel where high degradation rate is desirable. Among the mixture, the optimum fuel was found at the ratio of 60:40 of pyrolytic oil/coal mixtures with highest degradation rate. These findings may contribute to the development of a slurry fuel to be used in the vast existing conventional power plants.

  11. Identification of admixture for pelletization and strength enhancement of sintered coal pond ash aggregate through statistically designed experiments

    Highlights: • Sintered aggregate using pond ash from lignite and bituminous coal source. • Identification of admixtures and its dosage through design of experiments. • Clay, bentonite and kaolinite as binders enhance the strength of aggregate. • Use of calcium hydroxide with clay binder enhanced pelletization efficiency. • Use of borax with clay binders enhanced the strength of aggregate. - Abstract: Statistically designed experiments using Response Surface Methodology have been undertaken to identify the parameters influencing manufacturing process and properties of aggregate using coal pond ash (generated from bituminous and lignite coal sources). Based on the preliminary studies, Ca(OH)2 and borax have been identified as pelletization and strength enhancing admixture respectively. Pelletization efficiency of bituminous and lignite pond ash increased with an increase in binder and Ca(OH)2 dosage to 20–98% and 50–98% respectively, with proportionate quantity of water. Sintering has been used as a hardening method with temperature range of 900 °C and 1100 °C for a duration range of 45–120 min. Phase composition and sintered microstructure of aggregate has been reported using X-ray diffraction and scanning electron microscopy respectively. The ten percent fines value of aggregate with clay binder was 5.5 tonne as against a value of 4.5 tonne with aggregate with bentonite binder. Among the binders studied, bentonite resulted in high volume utilization of pond ash, i.e. up to 88%

  12. Bituminous reference document: synthesis of knowledge on the long time behavior of bituminous packages; Dossier de reference bitume: synthese des connaissances sur le comportement a long terme des colis bitumes

    Sercombe, J.; Adenot, F.; Vistoli, P.P.; Parraud, S.; Riglet-Martial, C.; Gwinner, B.; Felines, I.; Tiffreau, C.; Libert, M

    2004-07-01

    This document is a synthesis of the knowledge acquired at the CEA on the behavior of bituminous packages. In this framework, the CEA studied bituminous packages in generic conditions of a package lifetime. The main factors, the evolution mechanisms and influential parameters have been determined and quantitative s simulation have been developed. After a description of the main initial bituminous packages characterizations, the evolutions in saturated and un-saturated environment are exposed. (A.L.B.)

  13. Surface Properties of Photo-Oxidized Bituminous Coals: Final report

    NONE

    1998-09-01

    Natural weathering has a detrimental effect on the hydrophobic nature of coal, which in turn can influence clean-coal recovery during flotation. Few techniques are available that can establish the quality of coal surfaces and that have a short analysis time to provide input for process control. Luminescence emissions which can be quantified with an optical microscope and photometer system, are measurably influenced by degree of weathering as well as by mild storage deterioration. In addition, it has been shown that when vitrinite is irradiated with a relatively high intensity flux of violet- or ultraviolet- light in the presence of air, photo-oxidation of the surface occurs. The combination of measuring the change in luminescence emission intensity with degree of surface oxidation provided the impetus for the current investigation. The principal aim of this research was to determine whether clear correlations could be established among surface oxygen functionality, hydrophobicity induced by photo-oxidation, and measurements of luminescence intensity and alteration. If successful, the project would result in quantitative luminescence techniques based on optical microscopy that would provide a measure of the changes in surface properties as a function of oxidation and relate them to coal cleanability. Two analytical techniques were designed to achieve these goals. Polished surfaces of vitrain bands or a narrow size fraction of powdered vitrain concentrates were photo-oxidized using violet or ultraviolet light fluxes and then changes in surface properties and chemistry were measured using a variety of near-surface analytical techniques. Results from this investigation demonstrate that quantitative luminescence intensity measurements can be performed on fracture surfaces of bituminous rank coals (vitrains) and that the data obtained do reveal significant variations depending upon the level of surface oxidation. Photo-oxidation induced by violet or ultraviolet light

  14. Aggregate productivity and aggregate technology

    Susanto Basu; John G. Fernald

    1997-01-01

    Aggregate productivity and aggregate technology are meaningful but distinct concepts. We show that a slightly-modified Solow productivity residual measures changes in economic welfare, even when productivity and technology differ because of distortions such as imperfect competition. We then present a general accounting framework that identifies several new non-technological gaps between productivity and technology, gaps reflecting imperfections and frictions in output and factor markets. Empi...

  15. Effects of salt content on leaching properties of synthetic bituminized wastes

    The leaching properties of soluble components (Na+, NO3−, and NO2−) in synthetic bituminized wastes with various characteristics, such as salt content, salt composition, and bitumen matrix, were quantitatively evaluated by means of an aqueous leaching test. Micropores were formed in the bituminized waste by the leaching of soluble salts. The penetrability of bitumen and the salt content affected the size and the shape of the micropores observed by scanning electron microscopy. The linear relationship between leaching fraction of the soluble components and square root of leaching time was observed, and the diffusion coefficient of the soluble component was determined by Fick's law. The diffusion coefficients of ionic species of interest were similar to each other. Moreover, the diffusion coefficient agreed among bituminized wastes with the same salt content, even if salt composition and bitumen matrix were different. The diffusion coefficient of the component was proportional to the salt content in the synthetic bituminized wastes. It was found that the salt content in the bituminized waste was one of the key factors to determine the diffusion coefficient. (author)

  16. Global market trade policy analysis for petroleum oils and oils obtained from bituminous minerals, crude

    Bagheri, F.

    2012-01-01

    Full Text Available This article is based on surveying the custom tariffs imposed on the world export market of Petroleum Oils and Oils Obtained from Bituminous Minerals, Crude. We obtained the data according to the most updated available data provided online by UNCTAD and World Bank. The results indicate that none of the 142 countries in the world market of this product have imposed non-tariff trade barriers on the import of Petroleum Oils and Oils Obtained from Bituminous Minerals, Crude. The developed countries and the countries with transition economies are the main world import partners. European Union, United States, China, Japan, South Korea, Canada, Singapore, Taiwan, Thailand, South Africa, Australia, Turkey, Brazil, Sweden and Belarus are the examples and have imposed low custom tariffs on Petroleum Oils and Oils Obtained from Bituminous Minerals, Crude.

  17. Safety assessment for the bituminization facility of the medium-level waste

    The safety assessment for the home-made bituminization facility of the medium-level waste during hot test is made. The average external dose equivalent per month is 0.136 x 10-2 Sv. The radioactive substance released into the environment is much lower than the permissible limit. The danger of burning and exploding of the bituminized product is avoided because the operation temperature is controlled strictly below 170 C degree. The report also briefly describes the structural characteristic of the facility, the main process and radiation protection and safety measures

  18. Project and design of apparatus and equipment of pilot plant experimental bituminization line PS 44 EBO

    The modifications are described made in the design of major components of the pilot plant experimental bituminization line involving: the mixing equipment, the film rotor evaporator, the calciner, and various transport mechanisms for handling drums and containers. The difficulty and complexity of the problem which Kralovopolska strojirna Brno, the end supplier of the bituminization line, will have to tackle is evident mainly from the case of bridge cranes, which feed the line, and the full-portal gantry crane which handles the containers and drums at regional sites of radioactive waste disposal. (Z.M.)

  19. Installation in the A-1 plant of an experimental bituminization line by VUCHZ

    Following the termination of the experimental operation of the bituminization line at the Research Institute for Chemical Installations in Brno, the line was dismantled and transferred to the nucler power plant in Jaslovske Bohunice. The installation of the line, the layout of the assemblies are described and the results of tests with non-radioactive simulated wastes and actual radioactive wastes briefly described. An amount of 3.2 m3 of actual radioactive wastes from the V-1 nuclear power plant was processed in the tests. The results confirmed the suitability of bituminization for processing liquid radioactive wastes from WWER nuclear power plants. (Z.M.)

  20. 纤维沥青混合料的拌和成型工艺研究%Research on Mixing and Shaping Technology of Fiber Bituminous Mixture

    程英伟; 何晓鸣

    2012-01-01

    利用正交试验对剑麻纤维沥青混凝土混合料的拌和成型工艺进行研究.在固定配合比的前题下,以拌和方案、沥青加热温度、集料加热温度和成型温度为试验因素,模拟路面施工的各种拌和成型情况设计了L9正交表分别进行马歇尔试验.运用极差分析法对试验结果进行分析,确定了纤维沥青混合料拌和成型的优选方案为“同步法拌和+沥青加热温度为175℃+集料加热温度为206℃+成型温度为165℃”.最后分析了几种试验因素对试验指标的影响机理.%In this paper, mixing and shaping technology of bituminous concrete mixture with sisal fiber is researched by orthogonal experiment. Under a fixed mix proportion, mixing solutions, asphalt heating temperature, aggregate heating temperature and shaping temperature are selected as test factors. The variety of mixing and shaping in pavement construction is simulated by designing a L9 orthogonal table for Marshall tests. Range Analysis Method is used to analyze test results, and then the optimal scheme of mixing and shaping for fiber bituminous concrete mixture is determined. The optimal scheme is "synchronization method of mixing+asphalt heating temperature of 175℃+aggregate heating temperature of 206℃ + shaping temperature of 165℃”. Last, the influence mechanism of test factors on test indicators is analyzed.

  1. Use of waste plastic in construction of bituminous road

    Abhijeet Jirge

    2012-05-01

    Full Text Available Bottles, containers and packing strips etc. is increasing day by day. As a result amount of waste plastic also increases. This leads to various environmental problems. Many of the wastes produced today will remain in the environment for many years leading to various environmental concerns. Therefore it is necessary to utilize thewastes effectively with technical development in each field. Many by-products are being produced using the plastic wastes. Our present work is helping to take care of these aspects. Plastic waste, consisting of carry bags, cups and other utilized plastic can be used as a coating over aggregate and this coated stone can be used for roadconstruction. The mix polymer coated aggregate and tyre modified bitumen have shown higher strength. Use of this mix for road construction helps to use plastics waste. Once the plastic waste is separated from municipal solid waste, the organic matter can be converted into manure and used. Our paper will discuss in detail theprocess and its successful applications.

  2. Noise Reduction Properties of an Experimental Bituminous Slurry with Crumb Rubber Incorporated by the Dry Process

    Moisés Bueno

    2014-08-01

    Full Text Available Nowadays, cold technology for asphalt pavement in the field of road construction is considered as an alternative solution to conventional procedures from both an economic and environmental point of view. Among these techniques, bituminous slurry surfacing is obtaining an important role due to the properties of the obtained wearing course. The functional performance of this type of surfaces is directly related to its rough texture. Nevertheless, this parameter has a significant influence on the tire/road noise generation. To reduce this undesirable effect on the sound performance, new designs of elastic bituminous slurries have been developed. Within the FENIX project, this work presents the acoustical characterization of an experimental bituminous slurry with crumb rubber from wasted automobile tires incorporated by the dry process. The obtained results show that, under controlled operational parameters, the close proximity sound levels associated to the experimental slurry are considerably lower than those emitted by a conventional slurry wearing course. However, after one year of supporting traffic loads and different weather conditions, the evaluated bituminous slurry, although it conserves the original noise reduction properties in relation to the conventional one, noticeably increases the generated sound emission. Therefore, it is required to continue improving the design of experimental surfaces in order to enhance its long-term performance.

  3. Development and operation experience from pilot-plant for bituminization of liquid radioactive wastes (UBD-200)

    The results are given for investigations of liquid radioactive wastes bituminization on the pilot-plant of continious operation. The bituminization process is divided into two stages. On the first stage salts with definite moisture content are obtained. On the second stage, wet salts are mixed with melted bitumen. In this process the salts are finally dryed and bitumen compound produced is transported towards the discharge assembly. Design of the dryer and mixer is described and their technical parameters are given. Salt-bitumen compound is discharged in moulding bogies with volume of 0.5 m3. After hardening, salt-bitumen compound blocks are removed for burial. Average composition of liquid radioactive wastes coming for solidification is given. Dependences of the salt-bitumen compound characteristics on the parameters of the technological process of bituminization are given as well as the results of analysis of filling of compound by salts at the block height of 0.3 m. It is shown that division of the bituminization process into two stages do not affect on the chemical stability of compound. (I.T.)

  4. Towards an Accurate Stress Dependant Time & Frequency Domain VE Response Model for Bituminous Binders

    Woldekidan, M.F.; Huurman, M.; Pronk, A.C.

    2010-01-01

    Linear viscoelastic properties of bituminous binders for short loading times are analyzed using dynamic mechanical analysis methods. Dynamic Shear Rheometer (DSR) test with parallel plate (PP) configuration is widely used for this purpose. Due to the complex stress distribution over the cross-sectio

  5. Bituminization system of low level liquid waste in Genkai Nuclear Power Plant

    The bituminization system for low level radioactive liquid wastes has such advantages as its volume reduction is 6 to 10 times higher than the cementing systems, and the exuding ratio of radioactive nuclides from bituminized body into sea water is smaller, because the solids containing radioactive nuclides are solidified into oily bitumen which is very water repellent. Therefore, Genkai No.2 reactor plant has adopted the batch bituminization system, the main equipment of which being a drum mixer. This equipment has the capacity of treating 35 m3 of drain from the machines (boron 21,000 ppm) yearly, mainly composed of boric acid, and 85 m3 of floor drain/laundry drain yearly (solids 1.1 wt.%). This paper describes the outline of the system, the improvement of the installation, operating method, operation control, and the results of cold and hot operations. At the beginning of the trial operation, the concentrated laundry drain from No.1 reactor during the regular inspection was bituminized, and the concentrated sodium borate solution from No.2 reactor was treated since July, 1980. These results show the good volume reduction, condensate-processing capability, mixer controllability and mixer decontamination efficiency. (Wakatsuki, Y.)

  6. Effect of bituminous coal properties on carbon dioxide and methane high pressure sorption

    Weishauptová, Zuzana; Přibyl, Oldřich; Sýkorová, Ivana; Machovič, Vladimír

    2015-01-01

    Roč. 139, JAN 1 (2015), s. 115-124. ISSN 0016-2361 Institutional support: RVO:67985891 Keywords : bituminous coal * sorption capacity * maceral composition * Upper Silesian Coal Basin Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.520, year: 2014

  7. Testing of the possibility for the use of BEWAG-coal cinder in bituminous supporting layers of asphalt fastening

    Ueckert, H.W.

    1981-01-01

    In order to develop further use of coal cinder granulate the suitability of that granulate has been tested for use as an additional material for bituminous supporting layers. Results: (1) The granulate can be used for asphalt supporting layers Type B according TVT 72. (2) The granulation scope 0/5 mm is recommended. (3) The granular share of the mineral mixture can amount up to 30% of weight. (4) Standard-Bitumen B 65 can be used as bituminous binders. (5) The optimum consistence of the bituminous materials has to be found according of an aptitude test.

  8. Aggregation of Scale Efficiency

    Valentin Zelenyuk

    2012-01-01

    In this article we extend the aggregation theory in efficiency and productivity analysis by deriving solutions to the problem of aggregation of individual scale efficiency measures, primal and dual, into aggregate primal and dual scale efficiency measures of a group. The new aggregation result is coherent with aggregation framework and solutions for the other related efficiency measures that already exist in the literature.

  9. Transformism in Alberta: The Environmental Political Economy of the Bituminous Sands

    Katz-Rosene, Ryan

    This thesis attempts to help establish environmental political economy as a viable academic field while providing an example of work in the discipline. It offers an analysis of societal processes resulting in the co-optation and/or neutralization of critical environmentalist ideas. Using Alberta's bituminous sands as a case study, and a Gramsci-influenced eco-Marxist theory as a foundation, the thesis argues that the term 'environmental transformism' (inspired by the Gramscian term trasformismo) is helpful in describing and framing such processes. Accordingly, the ensuing chapters provide an analysis of why environmental transformism is happening in Alberta, and demonstrate how this mechanism works at protecting the status quo from threatening ideologies, thereby consolidating neoliberal capitalism. A concluding argument discusses the inherent dangers posed to society by the transformism of certain environmental subjectivities. The thesis begins by introducing the contentious social and environmental issues surrounding the development of the bituminous sands.

  10. Radiation-chemical transformation of synthetic oil from oil-bituminous rock

    Full text : Like as test subject was used synthetic oil from oil-bituminous rocks of Balakhany deposit. The regularities of synthetic oils radiation-chemical transformations were studied. Laboratory researches were carried out in an interval of absorbed dose 43-216 kGr and dose rate 0.5 Gr/s. Concentration, radiation-chemical yields of the received gases in the various absorbed doses were established. Results of researches allow to estimate possibility use of oil products received from synthetic oil for isolation of radioactive sources from environment. The purpose of the given work is research of radiation stability of synthetic oil from bituminous rock. Results of such researches will allow to estimate possibility of production different purpose oil products from synthetic oil in a radiation-chemical way and also use of these materials for isolation of radioactive sources from environment

  11. Long-term behavior of bituminized waste: modelling of auto-irradiation and leaching

    During interim storage, the main evolution factor of the bituminized wastes is radiolysis under auto-irradiation, while in deep disposal conditions, after radioactive decrease, site resaturation with water, and container corrosion, the main factor of evolution is leaching by water. This paper presents two models, designed to describe respectively radiolytic gas evacuation, and bituminized waste alteration under leaching. The first model is based on the integration of simple descriptions of gas production by radiolysis, gas diffusive transport, bubble nucleation and ripening, and bubble transport under buoyancy and viscosity. The second model is based on simple descriptions of water adsorption and solubilization at the surface, water diffusion into the matrix, water uptake by the most soluble salts, salt grain swelling and alteration of matrix waterproofing, diffusive transport of salts out of the waste. Copyright (2001) Material Research Society

  12. A Method to Estimate the Dynamic Displacement and Stress of a Multi-layered Pavement with Bituminous or Concrete Materials

    LU, ZHENG; Yao, Hailin; Zhang, JingBo

    2014-01-01

    In this research work, a method to estimate the dynamic characteristics of a multilayered pavement with bituminous or concrete materials is proposed. A mechanical model is established to investigate the dynamic displacement and stress of the multi-layered pavement structure. Both the flexible and the rigid pavements, corresponding to bituminous materials and concrete materials, respectively, are studied. The theoretical solutions of the multi-layered pavement structure are deduced considering...

  13. Is Atomic Force Microscopy suited as Tool for fast Screening of Bituminous Materials? An Inter-laboratory Comparison Study

    Nahar, S.N.; Dillingh, B.; Erkens, S.M.J.G.; Schmets, A. J. M.; Fischer, H.R.; Scarpas, A.; Schitter, G.

    2013-01-01

    Bituminous binders are known to have microstructures at typical length scales of micrometers. This microstructure can be probed with Atomic Force Microscopy (AFM). Now that worldwide several research groups are reporting AFM results on bitumen, it is becoming important to improve the understanding of the reproducibility and objectivity of the technique for studying bituminous samples. When reproducibility and stability are proven, AFM can be a tool for asphalt professionals to rapidly screen ...

  14. Modelling the quasi-static behaviour of bituminous material using a cohesive zone model

    Tabakovic, Amir; Karac, Aleksandar; Ivankovic, Alojz; Gibney, Amanda; McNally, Ciaran; Gilchrist, M. D.

    2010-01-01

    This paper investigates the applicability of a cohesive zone model for simulating the performance of bituminous material subjected to quasistatic loading. The Dugdale traction law was implemented within a finite volume code in order to simulate the binder course mortar material response when subjected to indirect tensile loading. A uniaxial tensile test and a threepoint bend test were employed to determine initial stress-strain curves at different test rates and the cohesive zone parameters (...

  15. Influence of properties of bituminous binders on the strength of formed coke

    Sharma, Ashok K.; Das, Bani P.; Tripathi, Prem S.M. [Central Fuel Research Institute, P.O. FRI-828108, Dhanbad (India)

    2002-03-20

    The role of different chemical characteristics (coking value, quinoline insolubles, elemental composition, {beta}-resin, toluene solubles) of various coal tar- and petroleum-based bituminous binders, such as heavy fraction of HTC tar, processed LTC tar, pitch and asphalt as also the mixed binder in controlling the strength of formed coke made from char prepared from non-coking Chirimiri coal and coke breeze (prepared after carbonising Jharia coal), respectively, has been studied in some detail. The objective was to investigate as to whether and how the properties of these bituminous binders govern the strength of formed coke. It is found that these properties of the binders do play significantly important role in controlling the strength of formed coke both during curing and carbonisation. These parameters of the binders are found to be closely related with their atomic C/H ratios. Notwithstanding the varying composition of the binders of different origin, be they coal tar or petroleum based, the atomic C/H ratio seems to be the most important characteristics of the bituminous binders, upon which the strength of formed coke depends predominantly. This also holds true when mixed binders were used. The results show that at a C/H ratio of about 1, the strength of the briquettes either on curing or on carbonising remains almost similar and that strong cured briquettes can be produced by using a bituminous binder with a C/H ratio less than 1, whilst for obtaining strong carbonised briquettes, binders with C/H ratio greater than 1 are preferable.

  16. Slagging behavior of upgraded brown coal and bituminous coal in 145 MW practical coal combustion boiler

    Akiyama, Katsuya; Pak, Haeyang; Takubo, Yoji [Kobe Steel, Ltd, Kobe (Japan). Mechanical Engineering Research Lab.; Tada, Toshiya [Kobe Steel, Ltd, Takasago (Japan). Coal and Energy Technology Dept.; Ueki, Yasuaki [Nagoya Univ. (Japan). Energy Science Div.; Yoshiie, Ryo; Naruse, Ichiro [Nagoya Univ. (Japan). Dept. of Mechanical Science and Engineering

    2013-07-01

    The purpose of this study is to quantitatively evaluate behaviors of ash deposition during combustion of Upgraded Brown Coal (UBC) and bituminous coal in a 145 MW practical coal combustion boiler. A blended coal consisting 20 wt% of the UBC and 80 wt% of the bituminous coal was burned for the combustion tests. Before the actual ash deposition tests, the molten slag fractions of ash calculated by chemical equilibrium calculations under the combustion condition was adopted as one of the indices to estimate the tendency of ash deposition. The calculation results showed that the molten slag fraction for UBC ash reached approximately 90% at 1,523 K. However, that for the blended coal ash became about 50%. These calculation results mean that blending the UBC with a bituminous coal played a role in decreasing the molten slag fraction. Next, the ash deposition tests were conducted, using a practical pulverized coal combustion boiler. A water-cooled stainless-steel tube was inserted in locations at 1,523 K in the boiler to measure the amount of ash deposits. The results showed that the mass of deposited ash for the blended coal increased and shape of the deposited ash particles on the tube became large and spherical. This is because the molten slag fraction in ash for the blended coal at 1,523 K increased and the surface of deposited ash became sticky. However, the mass of the deposited ash for the blended coal did not greatly increase and no slagging problems occurred for 8 days of boiler operation under the present blending conditions. Therefore, appropriate blending of the UBC with a bituminous coal enables the UBC to be used with a low ash melting point without any ash deposition problems in a practical boiler.

  17. Microstructural self-healing of bituminous materials: Combined experimental and numerical study

    Pauli, A; Schmets, A. J. M.; Kasbergen, C.; Varveri, K.; Scarpas, A.

    2013-01-01

    Bituminous materials form a class of materials that possess the intrinsic ability to selfheal. This self-healing capability is evidenced by the observation that the service life of these materials ‘in the field’ exceeds the service life as predicted by standard mechanical laboratory tests. This mismatch between laboratory prediction and field service life is usually accounted for by applying a shift or healing factor. In this contribution we demonstrate a model that is based on the observatio...

  18. Continuous bench-scale slurry catalyst testing direct coal liquefaction rawhide sub-bituminous coal

    Bauman, R.F.; Coless, L.A.; Davis, S.M. [and others

    1995-12-31

    In 1992, the Department of Energy (DOE) sponsored research to demonstrate a dispersed catalyst system using a combination of molybdenum and iron precursors for direct coal liquefaction. This dispersed catalyst system was successfully demonstrated using Black Thunder sub-bituminous coal at Wilsonville, Alabama by Southern Electric International, Inc. The DOE sponsored research continues at Exxon Research and Development Laboratories (ERDL). A six month continuous bench-scale program using ERDL`s Recycle Coal Liquefaction Unit (RCLU) is planned, three months in 1994 and three months in 1995. The initial conditions in RCLU reflect experience gained from the Wilsonville facility in their Test Run 263. Rawhide sub-bituminous coal which is similar to the Black Thunder coal tested at Wilsonville was used as the feed coal. A slate of five dispersed catalysts for direct coal liquefaction of Rawhide sub-bituminous coal has been tested. Throughout the experiments, the molybdenum addition rate was held constant at 100 wppm while the iron oxide addition rate was varied from 0.25 to 1.0 weight percent (dry coal basis). This report covers the 1994 operations and accomplishments.

  19. JV Task 126 - Mercury Control Technologies for Electric Utilities Burning Bituminous Coal

    Jason Laumb; John Kay; Michael Jones; Brandon Pavlish; Nicholas Lentz; Donald McCollor; Kevin Galbreath

    2009-03-29

    The EERC developed an applied research consortium project to test cost-effective mercury (Hg) control technologies for utilities burning bituminous coals. The project goal was to test innovative Hg control technologies that have the potential to reduce Hg emissions from bituminous coal-fired power plants by {ge}90% at costs of one-half to three-quarters of current estimates for activated carbon injection (ACI). Hg control technology evaluations were performed using the EERC's combustion test facility (CTF). The CTF was fired on pulverized bituminous coals at 550,000 Btu/hr (580 MJ/hr). The CTF was configured with the following air pollution control devices (APCDs): selective catalytic reduction (SCR) unit, electrostatic precipitator (ESP), and wet flue gas desulfurization system (WFDS). The Hg control technologies investigated as part of this project included ACI (three Norit Americas, Inc., and eleven Envergex sorbents), elemental mercury (Hg{sup 0}) oxidation catalysts (i.e., the noble metals in Hitachi Zosen, Cormetech, and Hitachi SCR catalysts), sorbent enhancement additives (SEAs) (a proprietary EERC additive, trona, and limestone), and blending with a Powder River Basin (PRB) subbituminous coal. These Hg control technologies were evaluated separately, and many were also tested in combination.

  20. Fatigue and healing properties of bituminous mastics reinforced with nano-sized additives

    Santagata, Ezio; Baglieri, Orazio; Tsantilis, Lucia; Dalmazzo, Davide; Chiappinelli, Giuseppe

    2016-03-01

    The research work described in the paper focused on fatigue and healing properties of bituminous mastics reinforced with nano-sized additives. Commercially available multiwall carbon nanotubes (CNTs) and montmorillonite nanoclay (NC) were combined with a single base bitumen and a standard mineral filler to produce bituminous mastics. These blends were prepared in the laboratory by making use of a technique consisting in simple shear mixing followed by sonication. Fatigue behaviour of mastics under repeated loading was investigated by means of time sweeps performed in the strain-controlled mode at various amplitudes. Healing potential was assessed by adopting a testing protocol specifically conceived to discriminate between recovery of damage induced by fatigue loading and other artefact phenomena which may affect material response. All rheological measurements were carried out with a dynamic shear rheometer in the parallel plates geometry. Outcomes of the experimental investigation were found to be highly dependent on the nature of additive type, as a result of the key role played by interaction mechanisms that nano-particles can establish within the bituminous mastic.

  1. Consistent Trade Policy Aggregation

    Anderson, James E.

    2008-01-01

    Much empirical work requires the aggregation of policies. This paper provides methods of policy aggregation that are consistent with two common objectives of empirical work. One is to preserve real income. The other is to preserve the real volume of activity in one or more parts of the economy. Trade policy aggregation is an acute example of the aggregation problem with thousands of highly dispersed trade barriers to be aggregated. An application to India shows that the standard atheoretic me...

  2. Consistency in Aggregation

    Ludwig Auer

    2004-01-01

    In empirical economic research, individual prices are often aggregated into average prices of sub-aggregates. Then, these average prices are aggregated to produce the average price of the total aggregate. Often, such two stage procedures help to illuminate the underlying forces driving the overall result. Since price data are usually published as price changes, this two stage aggregation is typically based on some price index formula. In this paper, various screening devices are introduced wh...

  3. Information-aggregation bias

    Goodfriend, Marvin

    1991-01-01

    Aggregation in the presence of data-processing lags distorts the information content of data, violating orthogonality restrictions that hold at the individual level. Though the phenomenon is general, it is illustrated here for the life-cycle-permanent-income model. Cross-section and pooled-panel data induce information-aggregation bias akin to that in aggregate time series. Calculations show that information aggregation can seriously bias tests of the life-cycle model on aggregate time series...

  4. Time dependent viscoelastic rheological response of pure, modified and synthetic bituminous binders

    Airey, G. D.; Grenfell, J. R. A.; Apeagyei, A.; Subhy, A.; Lo Presti, D.

    2016-04-01

    Bitumen is a viscoelastic material that exhibits both elastic and viscous components of response and displays both a temperature and time dependent relationship between applied stresses and resultant strains. In addition, as bitumen is responsible for the viscoelastic behaviour of all bituminous materials, it plays a dominant role in defining many of the aspects of asphalt road performance, such as strength and stiffness, permanent deformation and cracking. Although conventional bituminous materials perform satisfactorily in most highway pavement applications, there are situations that require the modification of the binder to enhance the properties of existing asphalt material. The best known form of modification is by means of polymer modification, traditionally used to improve the temperature and time susceptibility of bitumen. Tyre rubber modification is another form using recycled crumb tyre rubber to alter the properties of conventional bitumen. In addition, alternative binders (synthetic polymeric binders as well as renewable, environmental-friendly bio-binders) have entered the bitumen market over the last few years due to concerns over the continued availability of bitumen from current crudes and refinery processes. This paper provides a detailed rheological assessment, under both temperature and time regimes, of a range of conventional, modified and alternative binders in terms of the materials dynamic (oscillatory) viscoelastic response. The rheological results show the improved viscoelastic properties of polymer- and rubber-modified binders in terms of increased complex shear modulus and elastic response, particularly at high temperatures and low frequencies. The synthetic binders were found to demonstrate complex rheological behaviour relative to that seen for conventional bituminous binders.

  5. The projects of reducing environmental pollution at the collieries belonging to Petrosani Autonomous Bituminous Coal Administration

    The economic development in the Jiu Valley, as practised in the mining and processing of bituminous coal, has had a dynamic character without taking into account, however, the harmful impact on the environment. The most severe problem of environmental pollution in the Jiu Valley is that of the pollution of the Jiu River due to the discharge of waste water from the technological processes of mining and processing coal. This paper presents some solutions for reducing this environmental pollution, especially the Jiu water pollution. 1 ref

  6. Fire and explosion incident at bituminization demonstration facility of PNC Tokai works, on march 11, 1997

    On March 11, a fire and explosion incident occurred at the Bituminization Demonstration Facility (BDF) of Tokai Reprocessing Plant in Power Reactor and Nuclear Fuel Development Corporation (PNC). Soon after the incident, PNC (now reorganized to JNC) started to investigate the facility damage, operational records around the incident, technical notes including facility design and reviews of R and D results, operators witness and to perform several analysis, tests and calculations. This paper describes outline and cause of the incident which were concluded based on the results of continuous serious investigation, analysis and calculation. (author)

  7. Investigation of activity release from bituminized intermediate-level waste forms under thermal stresses

    To determine the consequences of a fire during fabrication, intermediate storage and transport of bituminized NaNO3 waste forms, the fractions of plutonium released from the waste forms were assessed. For this purpose, laboratory tests were made with PuO2-containing specimens as well as a field test with specimens containing Eu2O3. By the evaluation of plutonium release in the laboratory and by the determination of the total sodium release and the relative Eu/Na release in the field tests the plutonium release can be deduced from full-scale specimens. The results show that for bituminized waste forms with high NaNO3 contents (approx. 36 wt%) the average plutonium release obtained in laboratory testing is 15%. In the field tests (IAEA fire test conditions) an average Eu release of 8% was found. These results justify the statement that also for waste forms in open 175 L drum inserts a maximum plutonium release of about 15% can be expected. From the time-dependence of Eu/Na release in the field tests an induction period of 15-20 minutes between the start of testing and the first Na/Eu release can be derived. The maximum differential Na/Eu release occurs after a test period of 45 to 60 minutes duration and after 90 to 105 minutes (tests K2 and K4, respectively); after that time also the highest temperatures in the products are measured. The release values were determined for products in open 175 L drum inserts which in this form are not eligible for intermediate and ultimate storage. For bituminized waste forms in concrete packages (lost concrete shieldings) a delayed increase in temperature to only 70-80 deg. C takes place (4-5 hours after extinction of the fire) if the fire lasts 45 minutes. The concrete package remains intact under test conditions. This means that activity release from bituminized waste forms packaged in this way can be ruled out in the case under consideration. (author)

  8. Bituminization of radioactive waste concentrates from reprocessing, nuclear research establishments and nuclear power plants

    This report is a summary of the major results of R and D work performed at the Karlsruhe Nuclear Research Center from 1967 until 1977 for fixing radioactive waste concentrates in bitumen and for characterizing the resulting products. Moreover, the report provides a compilation of operating experience gathered at the Karlsruhe Nuclear Research Center in bituminizing low and medium level evaporator concentrates. The report also contains the results of R and D work carried out by external institutes on behalf of the KfK. (orig.)

  9. A Method to Estimate the Dynamic Displacement and Stress of a Multi-layered Pavement with Bituminous or Concrete Materials

    Zheng LU

    2014-12-01

    Full Text Available In this research work, a method to estimate the dynamic characteristics of a multilayered pavement with bituminous or concrete materials is proposed. A mechanical model is established to investigate the dynamic displacement and stress of the multi-layered pavement structure. Both the flexible and the rigid pavements, corresponding to bituminous materials and concrete materials, respectively, are studied. The theoretical solutions of the multi-layered pavement structure are deduced considering the compatibility condition at the interface of the structural layers. By introducing FFT (Fast Fourier Transform algorithm, some numerical results are presented. Comparisons of the theoretical and experimental result implied that the proposed method is reasonable in predicting the stress and displacement of a multi-layered pavement with bituminous or concrete materials. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6071

  10. Low SO2 emission from CFB co-firing MSW and bituminous.

    Lu, Qing-Gang; Li, Zhi-Wei; Na, Yong-Jie; Ba, Shao-Lin; Sun, Yun-Kai; He, Jun

    2004-01-01

    Influence of co-firing rate on SO2 emission from co-firing municipal solid waste (MSW) and bituminous containing high amount of sulfur (1.79%) was studied in a 0.15 MWt circulating fluidized bed (CFB). The temperature selected is 1123 K, typical for MSW incineration using CFB. The particle concentration in the dilution zone of the furnace, the alkali metal concentration and sulfate concentration in the recirculating ash and fly ash, and flue gas composition were determined. The results showed that the addition of MSW leads to a significant decrease in SO2 emission. Concentration of SO2 in flue gas decreased to 0 with the co-firing rate greater than 51%. This reduction in SO2 emission is attributed both to the high particle concentration in the dilution zone of the furnace, the high content of alkali metals in the bed material, and to the comparatively high concentration of HCI in flue gas during co-firing of MSW and bituminous. PMID:15559820

  11. THE HISTORY OF EXPLORATION AND EXPLOITATION OF BITUMINOUS AND KEROGENOUS DEPOSITS IN CROATIA

    Berislav Šebečić

    1995-12-01

    Full Text Available It is assumed thal the first known sedimens of natural bitumen or asphalt in coastal Croatia were exploited as the early moddle ages. Yet authenticated written documents about Vinišće near Trogir derive from no earlier than 1628, about Vrgorac/Paklina from only 1753. By the end of the 18th century, many deposits were discovered in Dalmatia, but it was Škrip on the Island of Brač and Suhi Dolac that were important. The earliest known deposits and occurrences of kerogenous rocks, or bituminous or oil shales, are mentioned as stone or fossil coal in Sovinjak, in the upper course of the River Mirna, and in Rebići in Istria; near Sinj, Slivno not far from the River Neretva, Mirta and near Nerežišće on the Island uf Brač. All if these were well known and described in 1804, while Sovinjak was mentioned in the 16th century. In the article, some of new information derived from mining and geological research into bituminous and kerogenous sediments and deposits are provided (the paper is published in Croatian.

  12. Assessing radioactive concentrates and waste vapor condensate in solidifying radioactive wastes by bituminization

    A brief overview is presented of chemical and radiochemical methods used in the world for the analysis of the concentrate of liquid radioactive wastes from nuclear power plants destined for bituminization. Most methods are also suitable for an analysis of the condensate of waste vapors produced in bituminization. The methods of analysis of the radioactive concentrate from the V-1 nuclear power plant in Jaslovske Bohunice and of the waste vapors condensate were developed and tested in practice. Gross gamma activity was measured using a well-type Na(Tl) scintillation detector, the content of radionuclides was determined using semiconductor Ge(Li) spectrometry. The concentration of boric acid in the concentrate was determined by titration with mannite; in the condensate, using spectrophotometry with curcumine. The content of nitrates in both the concentrate and the condensate was determined spectrophotometrically using salicylic acid, the content of nitrites was determined by spectrophotometry using sulfanilic acid and α-naphthylamine. Carbonates and chlorides were determined by titration, sodium and potassium by flame photometry. The content of organic acids was measured by gravimetry of extracted methyl esters, the content of surfactants by spectrophotometry. Infrared spectrophotometry was used in determining hydrocarbons in the waste vapor condensate. The measured value range and the measurement errors are shown for each method. (A.K.)

  13. Feasibility study of producing lump fuel using oil-bituminous sands

    Moldybaev, A.B.; Ermagambetov, B.T.; Mamraeva, K.M.; Shin, R.G.; Bakirova, R.K. (Institut Organicheskogo Sinteza i Uglekhimii AN KazSSR (USSR))

    1991-04-01

    Describes production of lump fuel by briquetting and coking different mixtures of non-caking coal with coal preparation sludge and bitumen extracted from oil sands. The coal used was from the Shubarkol'sk coal deposit (USSR); the sludge was from the Saburkhanskaya preparation plant. Properties and composition of oil-bituminous sands and of bitumen to be used as binder are given. Technological details of the briquetting and coking processes are provided. Results show that briquets produced from mixtures of coal and oil-bituminous sands can only be used as a high-ash lump fuel, which cannot be further processed into semicoke. Experiments were carried out briquetting coal or coke, sludge and 6-8% bitumen extracted from the sands, varying coal or coke grain fractions and composition of the mixture. An increased briquet strength was found after using the vacuum-distilled 300-350 C bitumen fraction. Briquets from this non-caking coal with bitumen binder are regarded as ecologically clean fuel. 5 refs.

  14. Utilization of Waste Clay from Boron Production in Bituminous Geosynthetic Barrier (GBR-B) Production as Landfill Liner

    Müfide Banar; Yücel Güney; Aysun Özkan; Zerrin Günkaya; Eren Bayrakcı; Derya Ulutaş

    2016-01-01

    Bituminous geomembranes, one type of geosynthetics, include a hot bituminous mixture with mineral filler and reinforcement. In this study, boron production waste clay (CW) was used as filler to produce a geosynthetic barrier with bentonite, waste tire, and bitumen. Bentonite and waste tires were used as auxiliary fillers and bitumen as the binder. CW/bitumen, CW/bentonite/bitumen, and CW/waste tire/bitumen mixtures were prepared by using a laboratory mixer at 100°C. Hot mixtures were extruded...

  15. Platelet aggregation test

    The platelet aggregation blood test checks how well platelets , a part of blood, clump together and cause blood to clot. ... Decreased platelet aggregation may be due to: Autoimmune ... Fibrin degradation products Inherited platelet function defects ...

  16. Aggregation in manpower planning

    Wijngaard, J

    1983-01-01

    In manpower planning, as in all other kinds of planning, an important choice is the level of aggregation. The proper level of aggregation depends on the flexibility (mobility) of the personnel. This dependency is investigated in this paper. The manpower system considered is characterized by two dimensions, level and function group. Conditions are derived for aggregate long-term planning (aggregation over function group) combined with one-period disaggregation being optimal.

  17. Aggregating Reputation Feedback

    Garcin, Florent; Faltings, Boi; Jurca, Radu

    2009-01-01

    A fundamental task in reputation systems is to aggregate multiple feedback ratings into a single value that can be used to compare the reputation of different entities. Feedback is most commonly aggregated using the arithmetic mean. However, the mean is quite susceptible to outliers and biases, and thus may not be the most informative aggregate of the reports. We consider three criteria to assess the quality of an aggregator: the informativness, the robustness and the strategyproofness, and a...

  18. Protein aggregation and bioprocessing

    Cromwell, Mary E. M.; Hilario, Eric; Jacobson, Fred

    2006-01-01

    Protein aggregation is a common issue encountered during manufacture of biotherapeutics. It is possible to influence the amount of aggregate produced during the cell culture and purification process by carefully controlling the environment (eg, media components) and implementing appro-priate strategies to minimize the extent of aggregation. Steps to remove aggregates have been successfully used at a manufacturing scale. Care should be taken when developing a process to monitor the compatibili...

  19. Development prospects for Bazhenov formation bituminous claystones in the southeast of the West Siberian Plate (Tomsk Region)

    The article considers the use of time-tested bituminous shale development technologies in the southeast of the West Siberian Plate (Tomsk Region). A research target is the bituminous claystones of the Bazhenov formation. The Bazhenov formation was divided into stratigraphic units, and the sequence of forming these units within the territory under study was restored on the basis of the peculiarities of the Bazhenov formation section structure with gamma-ray logging data. The joint analysis of logs (gamma-ray logging, resistivity logging, SP logging, neutron gamma-ray logging, induction logging) and core data revealed the wide development of carbonatization processes in the lower stratigraphic units of the Bazhenov formation, whereas the upper, most bituminous units do not have the signs of carbonatization. It is a favorable factor for using the existing technologies of producing hydrocarbons from analogous sedimentary deposits. Considering the degree of lithological disconnection of an oilbearing object from adjacent reservoir formations allows making a conclusion that the application of the existing technologies for developing bituminous claystones can be implemented only in the insignificant territory of the area under study where the Bazhenov formation overlies Georgiev formation claystones being over 8 meters thick. To develop the oil and gas potential of the Bazhenov formation in other territories, there will be a need for new technologies that allow forming a fracture-cavernous matrix in a carbonate rock

  20. Examination and comparision of structure: lignite, bituminous and anthracite coal. [10 references

    Winans, R.E.; Hayatsu, R.; Scott, R.G.; Moore, L.P.; Studier, M.H.

    1976-01-01

    Coal can be described as an amorphous mixture of macromolecules each made up of a complex array of organic molecules chemically linked together. Methods for breaking up these macromolecules in order to characterize the aromatic structural types have been explored. Pyrolysis is a common method for depolymerizing coal, but under the conditions necessary for pyrolysis much structural rearrangement occurs making a comparison of the products to the initial structural groups in coal difficult if not impossible. One approach has been to use a variety of selective oxidation methods. Aqueous sodium dichromate, aqueous air oxidation with uv light, and hydrogen peroxide in acetic acid have been used. Initial results of some of these studies have been published. This work has been extended to include characterization and comparison of a lignite, bituminous coal, and anthracite. Besides the oxidation products, the monomeric organic molecules trapped within the macromolecules are examined and the results interpreted in relation to coal structure and the coalification process.

  1. Bituminization of simulated waste, spent resins, evaporator concentrates and animal ashes by extrusion process

    The results of the study of bituminization of simulated radwaste - spennt ion-exchange resins, borate evaporator/concentrates and animal ashes, are presented and discussed. Distilled and oxidizer bitumen were used. Characterization of the crude material and simulated wastes-bitumen mixtures of varying weigt composition (30, 40, 50, 60% by weight of dry waste material) was carried out. The asphaltene and parafin contents in the bitumens were also determined. Some additives and were used with an aim to improve the characteristcs of solidified wastes. For leaching studies, granular ion-exchange resins were with Cs - 134 and mixtures of resin-bitumen were prepared. The leaching studies were executed using the IAEA recommendation and the ISO method. A conventional screw-extruder, common in plastic industry, was used determine operational parameters and process difficulties. Mixtures of resin-bitumen and evaporator concentrate-bitumen obtained from differents operational conditions were characterized. (Author)

  2. Physical properties of solid fuel briquettes from bituminous coal waste and biomass

    ZARRINGHALAM-MOGHADDAM A; GHOLIPOUR-ZANJANI N; DOROSTIS; VAEZ M

    2011-01-01

    Biomass and bituminous coal fines from four different coalfields were used to produce fuel briquettes.Two physical properties of briquettes,water resistance index and compressive strength were analyzed.The influence of type and quantity of biomass on physical properties was also studied.The results reveal that depending on the mineral content of the coal,the physical properties of the briquettes differ noticeably.The comparison of briquettes with and without biomass showed that the presence of the beet pulp increased CS in all types of coal samples.Samples containing beet pulp had better physical properties than sawdust.Mezino Ⅱ coal briquettes had highest CS and WRI than the other ones.Calorific value of biomass/Mezino Ⅱ coal briquettes was lessened in comparison with raw coal,but it remained in an acceptable range.

  3. Combustion characteristics and arsenic retention during co-combustion of agricultural biomass and bituminous coal.

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui; Hu, Yunhu

    2016-08-01

    A combination of thermogravimetric analysis (TG) and laboratory-scale circulated fluidized bed combustion experiment was conducted to investigate the thermochemical, kinetic and arsenic retention behavior during co-combustion bituminous coal with typical agricultural biomass. Results shown that ignition performance and thermal reactivity of coal could be enhanced by adding biomass in suitable proportion. Arsenic was enriched in fly ash and associated with fine particles during combustion of coal/biomass blends. The emission of arsenic decreased with increasing proportion of biomass in blends. The retention of arsenic may be attributed to the interaction between arsenic and fly ash components. The positive correlation between calcium content and arsenic concentration in ash suggesting that the arsenic-calcium interaction may be regarded as the primary mechanism for arsenic retention. PMID:27136608

  4. Application of laser microprobe (LAMMA 1000) to "fingerprinting" of coal constituents in bituminous coal

    Lyons, P.C.; Hercules, D.M.; Morelli, J.J.; Sellers, G.A.; Mattern, D.; Thompson-Rizer, C. L.; Brown, F.W.; Millay, M.A.

    1987-01-01

    A laser microprobe (LAMMA-1000) microchemical analysis of vitrinites of different morphologies but similar reflectances within the same bituminous coal bed indicates distinct "fingerprint" spectra. The banded form of vitrinite contains Li, Ti, Ba, Sr, F, and Cl which were not detected in the nonbanded vitrinite. These differences may indicate a different plant source or the introduction of these elements from fluids mobilized during diagenesis. The nonbanded vitrinite (called corpocollinite), which was contained in a pyrite coal-ball seed fern permineralization of Myeloxylon, may have been protected from influx of these elements due to entrapment by pyrite during an early peat stage. An ion at M/Z 65, which is characteristic of the banded vitrinite, may indicate C5H5+ and, perhaps a difference in the chemical structure of the two vitrinites. These results demonstrate that "fingerprint" spectra can be obtained from vitrinite macerals by LAMMA and that these "fingerprints" have genetic implications. ?? 1987.

  5. Progress in developing a model for interaction of bituminized waste products with water

    The reported work is part of a study of long-term properties of bituminized waste products. The long-term goal is: - estimating the swelling and degradation of an agglomerate of ion exchange resins and bitumen when submerged in water, - estimating the consequent pressure build-up and degradation of surrounding barriers in the repository. The report describes the first steps in calculating diffusion of water into the heterogeneous medium of ion exchange resins and bitumen and the consequent swelling of the material. Different models for the effective diffusivity are applied and implemented into a new version of the code GEOPATH which then also considers the swelling due to water uptake. Two-dimensional cylindrical geometry is considered. Results from some test calculations are shown. It is concluded that swelling is an important effect which can be handled theoretically if basic data are available. (authors)

  6. Comparative study of test methods for bituminized and other low- and medium-level solidified waste materials

    Various aspects of the behaviour of bituminized or cemented simulated low- or medium-level radioactive waste in contact with water or salt solutions have been investigated. The solubility (approximately 0.5%) and the diffusion coefficient (approximately 5.10-8 cm2/sec) determining transort of water in pure bitumen have been measured for Mexphalte 40/50 at room temperature. A weighing method has been used to study water uptake and swelling of bituminized sodium nitrate, sodium sulphate or cation-exchange resin. The swelling of samples in contact with water was in some cases very pronounced. In strong salt solutions the tendency to swell is much less. The particle size of the embedded waste material is an important parameter. Thermal pre-treatment of cation-exchange resin before bituminization does not seem to improve the quality of the final product. The interaction between bituminized-exchange resin and concrete barrier materials has been studied. Microbial degradation of bitumen and bituminized waste under aerobic conditions has been investigated. It is probably of minor importance as far as leaching is concerned. A method for measuring leaching from a plane surface of cemented waste has been developed. The method avoids the problem of cracks between the sample and the container. Leaching from cemented sodium nitrate or sulphate was investigated. Absorption of CO2 from the atmosphere was found to have only minor effect on Cs- and Na-leaching but gave a pronounced decrease in Ca-leaching. The use of silica-fume as an additive to cemented sodium nitrate decreased the leach rate by a factor 4. (author)

  7. Uraniferous lignites and bituminous clays of the Serres Basin. Pt. A

    The lignites of the southern area (Christos-Vissiani-Lefkes-Perdikari) and the bituminous clay silts of the northern area (Maramena, Ano Metohi, Chrysopigi) are the main uraniferous beds in the Serres Basin. The sediments of the basin (Upper Miocene to recent) have been stratigraphically divided into three informal unities: the Lefkon, Georgios and Spilia formations. The uraniferous lignites pertaining to the Lefkon limnic-fluvial formation are developed into two discrete horizons, the upper Double Seam and the lower Main Seam. The bituminous clays are of the same age with the lignites, those of Maramena being, however, younger, equivalent to the marine and brackish Georgios formation. The continuity, thickness and dip of the strata reveal considerable regional changes resulting from the intense tectonism of the basin. Further to the surface works the upper lignites have been reached through small excavations and also about 100 boreholes totalling 10,000 m have been drilled. The composition of the organic constituents and the calorific value show a dull transitional to shiny hard lignite with ash rich in pyrite and sulphur. There have been no discrete U minerals detected, while the electron microprobe analysis showed that the uranium is uniformly disseminated into the lignite mass, mainly absorbed through its humic acids. More than 75% of the uranium is extractable, the control of its combustion conditions being, however, a major problem. The potential reserves have been up to date estimated to be of over 4,000 tons (uranium metal), this figure resulting mainly from data evaluated from the borehole γ-ray logs using the computer programmes LOGFILE and LOGPLOT developed at the Radioactive Raw Materials Dept. of the Greek AEC. (author)

  8. Kinetics and equilibrium modeling of uranium(VI) sorption by bituminous shale from aqueous solution

    Highlights: • Oil shales are sedimentary rocks containing a polymeric matter in a mineral matrix. • Sorption potential of bituminous shale (BS) for uranium recovery was investigated. • U(VI) sorption increased with decreasing pH and increasing temperature. • Kinetic data were analyzed based on single and two resistance diffusion models. • The results fit well to the McKay equation assuming film and intraparticle diffusion. - Abstract: Sorption of U(VI) onto a bituminous shale (BS) from a nuclear power plant project site in Black Sea region was investigated for potential risk assessment when it releases into the environment with contaminated ground and surface water. The sorption characteristics of the BS for U(VI) recovery were evaluated as a function of contact time, adsorbent dosage, initial concentration, pH and temperature. Kinetic results fit better with pseudo-second-order model rather than pseudo-first-order. The possibility of diffusion process was analyzed based on Weber–Morris intra-particle diffusion model. The McKay equation assuming film- and intraparticle diffusion better predicted the data than the Vermeulen approximation presuming surface diffusion. Equilibrium sorption data were modeled according to the Langmuir, Dubinin–Radushkevich (D–R) and Freundlich isotherm equations. Sorption capacity increased from 0.10 to 0.15 mmol g−1 in 298–318 K temperature range. FT-IR analysis and pH dependent sorption studies conducted in hydroxide and carbonate media revealed that U(VI) species were sorbed in uranyl and its hydroxo forms on the BS. Desorption studies showed that U(VI) leaching with Black Sea water was negligible from the loaded BS. The activation parameters (Ea, ΔH∗ and ΔG∗) estimated from diffusion coefficients indicated the presence of an energy barrier in the sorption system. However, thermodynamic functions derived from sorption equilibrium constants showed that overall sorption process was spontaneous in nature and

  9. Distribution of inorganic and organic substances in the hydrocyclone separated Slovak sub-bituminous coal

    Anton Zubrik; Slavomir Hredzak; Ludmila Turcaniova; Michal Lovas; Ingo Bergmann; Klaus Dieter Becker; Maria Lukcova; Vladimir Sepelak [Slovak Academy of Sciences, Kosice (Slovakia). Institute of Geotechnics

    2010-08-15

    A low-rank Slovak sub-bituminous coal from the Handlova deposit was physically treated by washing in a water-only cyclone with the goal to find the separation effect for inorganic (mainly Fe-bearing minerals) and organic substances (humic acids, diterpanes). A high-quality coal product with the ash content in the dry matter of 9.02% and carbon content of C{sup d} = 68.12% at a mass yield of 29.51% was obtained using the water-only cyclone processing. At first, the physically treated coal samples were detailed characterized by XRD, {sup 57}Fe Moessbauer spectroscopy, FT-IR and HR-TEM. In addition to non-crystalline organic coal components, inorganic compounds belonging to silicate minerals (kaolinite, muscovite and quartz) as well as to Fe-bearing sulphide minerals (pyrite) were identified in the sub-bituminous coal by XRD. {sup 57}Fe Moessbauer spectroscopy detected the presence of iron carbonate (siderite), iron-containing clay mineral and two sulphur-containing minerals (pyrite, jarosite) in the untreated coal. On the other hand, only one Fe-bearing mineral, (pyrite) was found in the washed coal. Effect of the physical separation is also demonstrated in FT-IR spectra, where the peak at 1040 cm{sup -1} representing the silicate component in the untreated sample is not detectable in the washed coal sample. Presence of extractive organic substances, i.e. humic acids and tetracyclic diterpane (16a(H)-phyllocladane), in the hydrocyclone products is also evidenced. It was confirmed that the isolated diterpenoic compound is attendant in the washed product with the lowest ash content and it is assimilated with the organic part of coal. Surprisingly, humic acids were found in the highest concentration in the slurry that has the highest content of ash (63.14%). 54 refs., 8 figs., 5 tabs.

  10. Inoculum density of Glomus mosseae and growth of onion plants in unsterilized bituminous coal spoil

    Khan, A.G.

    1988-01-01

    The effect of inoculum, density (number of vesicular-arbuscular mycorrhizal (VAM) propagules g/sup -1/ of inoculum) on the growth of onions (Allium cepa L.) infected by Glomus mosseae (Nicol and Gerd). Gerdemann and Trappe, Comb nov in unsterilized coal spoil containing indigenous VAM fungi, including G. mosseae, was investigated. The amount of onion roots converted to mycorrhizas by inoculant fungus, estimated by a gridline intersect method, increased with inoculum density (..gamma..0.62, P0.05) until a plateau was reached. Onion growth responses also increased significantly (P<0.05) with the amount of VAM inoculum present in the coal spoil. The initial linear relationship between inoculum propagules (MPN estimates), percent colonization of onion roots and onion shoot dry weight became quadratic as the number of infection propagules increased. VAM infection had no significant effect on root:shoot ratios. Similarly there was no significant interaction (P>0.05) between the inoculum density, VAM-colonized root mass and the onion root:shoot fresh weight ratios. The amount of the windswept bituminous coal spoil bound to VAM (presumably because of VAM external hyphae) also increased as inoculum density increased (..gamma..0.63, P<0.05). There was a stronger correlation (ga0.85, P<0.05) between the amount of spoil adhered per plant and the root fresh wt plant/sup -1/ indicating that root effects were primarily responsible for increasing spoil adherence. There were negative correlations (P<0.05) between root fresh wt plant/sup -1/ (..gamma..-0.68), inoculum density (..gamma..-0.589), percent root elngth infected (..gamma..-0.73) and the amount of spoil adhered g/sup -1/ root fresh wt. The possible exploitation of VAM in revegetation of bituminous coal spoil is discussed. 25 refs., 2 tabs.

  11. Provenance for Aggregate Queries

    Yael Amsterdamer; Daniel Deutch; Val Tannen

    2011-01-01

    We study in this paper provenance information for queries with aggregation. Provenance information was studied in the context of various query languages that do not allow for aggregation, and recent work has suggested to capture provenance by annotating the different database tuples with elements of a commutative semiring and propagating the annotations through query evaluation. We show that aggregate queries pose novel challenges rendering this approach inapplicable. Consequently, we propose...

  12. Diffusion in aggregated soil.

    Rappoldt, C.

    1992-01-01

    The structure of an aggregated soil is characterized by the distribution of the distance from an arbitrary point in the soil to the nearest macropore or crack. From this distribution an equivalent model system is derived to which a diffusion model can be more easily applied. The model system consists of spherical, or cylindrical or plane aggregates, which do not represent the individual aggregates of the soil, however. The radii of the spheres, cylinders or plane sheets represent different le...

  13. The Aggregate-Supply/Aggregate-Demand Model

    BARRO, Robert J.

    1994-01-01

    The aggregate-supply/ aggregate-demand (AS-AD) model is popular in textbooks, but has problems with logical consistency. In one interpretation, the Keynesian underpinnings of the AD curve-derived from the IS/LM model with downward price stickiness-conflict with the determination of the price level at the intersection of the AS and AD curves. In another view, the model corresponds to rational-expectations theories in which Keynesian properties are absent. In a third interpretation, the model i...

  14. An Aggregation Matrix MATLAB Function

    Caleb Stair

    2013-01-01

    This Technical Document describes the foundations for an aggregation matrix function implemented in MATLAB, including the format and structure of the required aggregation vector used as an argument to the function. The function is passed with the N-dimensional aggregation vector as an argument. The aggregation vector contains N values ranging from 1 to M, each of which is the aggregate index corresponding to the N pre-aggregation indices. The function returns an aggregation matrix with M rows...

  15. DOES CONSISTENT AGGREGATION REALLY MATTER?

    Shumway, C. Richard; Davis, George C.

    2000-01-01

    Consistent aggregation assures that behavioral properties which apply to disaggregate relationships also apply to aggregate relationships. The agricultural economics literature is reviewed which has tested for consistent aggregation or measured statistical bias and/or inferential errors due to aggregation. Tests for aggregation bias and errors of inference are conducted using indices previously tested for consistent aggregation. Failure to reject consistent aggregation in a partition did not ...

  16. DOES CONSISTENT AGGREGATION REALLY MATTER?

    Shumway, C. Richard; Davis, George C.

    2000-01-01

    Consistent aggregation assures that behavioral properties, which apply to disaggregate relationships also, apply to aggregate relationships. The agricultural economics literature is reviewed which has tested for consistent aggregation or measured statistical bias and/or inferential errors due to aggregation. Tests for aggregation bias and errors of inference are conducted using indices previously tested for consistent aggregation. Failure to reject consistent aggregation in a partition did no...

  17. The effect of petrographical composition of coals and bituminous sediments on the material and isotopic composition of dry natural gases from artificial recoalification reactions. 2

    Experimental results indicate that on the basis of the material and isotopic composition of natural gases conclusions can be drawn with regard to the character (humic or bituminous) of the parent rock. Thus, genetic relations assumed to exist between humic sediments (e.g. coal seams) and dry natural gases as well as bituminous rocks and wet natural gases are experimentally confirmed. In addition, from analyses of the materials approximate data can be derived on the degree of carbonization of coal or bituminous sediments in the main phase of gas separation. Furthermore, these analyses were used to elucidate the question whether authochthonous or allochthonous deposits are present. It could be shown that the maceral composition of coals and of the organo-petrographical inclusions in bituminous sediments determines the isotopic composition of methane in recoalification gases to a considerable degree. (author)

  18. Study on the cause of the fire and explosion incident at Bituminization Demonstration Facility of PNC Tokai Works

    On March 11, 1997, a fire and explosion incident occurred in Bituminization Demonstration Facility (BDF) at Tokai Reprocessing Plant (TRP). The cause of the incident was thoroughly investigated and after thirty meetings of 'Investigation Committee of Science and Technology Agency (STA)'. STA reported possible cause of this incident. Continually detailed investigation was discussed at 'Follow-up Committee of STA'. Based on the results of five meetings, JNC concluded that the main cause of fire was frictional heating and viscous heating in the extruder, which provided an unusually high temperature in the bituminized product at filling, since there was no chemical analysis data suggesting the generation of chemical heat. It is considered that these excessive heat generations were due to the decreased feed rate of liquid waste to the extruder. The Follow-up Committee almost agreed to this conclusion. This paper describes general information concerning the incident and details of the cause of the incident. (author)

  19. Effect of organic calcium compounds on combustion characteristics of rice husk, sewage sludge, and bituminous coal: thermogravimetric investigation.

    Zhang, Lihui; Duan, Feng; Huang, Yaji

    2015-04-01

    Experiments were conducted in a thermogravimetric analyzer to assess the enhancement of combustion characteristics of different solid fuels blended with organic calcium compounds (OCCs). Rice husk, sewage sludge, and bituminous coal, and two OCC were used in this study. Effect of different mole ratios of calcium to sulfur (Ca/S ratio) on the combustion characteristics were also investigated. Results indicated that combustion performance indexes for bituminous coal impregnated by OCC were improved, however, an inverse trend was found for sewage sludge because sewage sludge has lower ignition temperature and higher volatile matter content compared to those of OCC. For rice husk, effect of added OCC on the combustion characteristics is not obvious. Different solid fuels show different combustion characteristics with increases of Ca/S ratio. The maximum combustion performance indexes appear at Ca/S ratios of 1:1, 2:1, and 3:1 for OCC blended with Shenhua coal, rice husk, and sewage sludge, respectively. PMID:25638405

  20. The bituminization in Marcoule and la Hague plants. Description of the processes and the fire risk prevention

    Chemical precipitation is an efficient process to decontaminate liquid effluents and has been selected as early as 1966 for the liquid waste treatment of MARCOULE. The process has been designed by the French CEA and improved along the time. The first implementation in LA HAGUE was for the STE 2 facility (Station de Traitement d'Effluents no 2). A new facility, STE 3, has been commissioned in 1989 in LA HAGUE, benefiting from these previous experience and therefore contributing into a drastic reduction of liquid discharges. The sludges coming from the treatment in MARCOULE and STE 3 are bituminized into continuous extruders. The resulting waste is kept in interim storage, waiting for final disposal. The industrial production, up to now, is close to 10000 drums (55 gallons) in LA HAGUE and 60000 drums in MARCOULE. A retrieval operation of the MARCOULE drums from the present storage has been launched to send them into a recently built interim storage operating since the beginning of 2000. At the present time, in LA HAGUE, evaporation has been preferred to chemical precipitation for the treatment of liquid effluents. After concentration, the effluents go to the vitrification and the volume of resulting waste is much smaller. However, bituminization is still the preferred option for the 10000 m3 of sludges resulting from the STE 2 operations which are being stored in tanks. A complete reevaluation of the operation safety measures of bituminization has been made lately in both plants following recent incidents on other installations. The paper describes the chemical precipitation and the bituminization processes and focuses on safety measures which are implemented for prevention, detection and fight. (authors)

  1. Dye-adsorption capacity of bituminous fly ash and its pozzolanic property after used as dye-adsorbent

    Penpolcharoen, M.

    2004-01-01

    Bituminous fly ash, which is an industrial waste, was used as an adsorbent to remove dyestuff from the textile-dye wastewater. The batch kinetic and isotherm experiments of the synthetic wastewater were firstly conducted to determine the adsorption behavior and optimal conditions for adsorption. The optimal conditions were then applied to the actual textile-dye wastewater. Under the original conditions of fly ash and wastewater, the results indicated that the color could be removed up to 86.6...

  2. Charged Dust Aggregate Interactions

    Matthews, Lorin; Hyde, Truell

    2015-11-01

    A proper understanding of the behavior of dust particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the dust aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions leading to the observed interactions. This research is funded by NSF Grant 1414523.

  3. Utilization of Waste Clay from Boron Production in Bituminous Geosynthetic Barrier (GBR-B Production as Landfill Liner

    Müfide Banar

    2016-01-01

    Full Text Available Bituminous geomembranes, one type of geosynthetics, include a hot bituminous mixture with mineral filler and reinforcement. In this study, boron production waste clay (CW was used as filler to produce a geosynthetic barrier with bentonite, waste tire, and bitumen. Bentonite and waste tires were used as auxiliary fillers and bitumen as the binder. CW/bitumen, CW/bentonite/bitumen, and CW/waste tire/bitumen mixtures were prepared by using a laboratory mixer at 100°C. Hot mixtures were extruded into strips by using a lab-scale corotating twin screw extruder (L/D: 40 followed by die casting (2 mm × 100 mm. Glass fleece or nonwoven polyester was used as reinforcement material and while die casting, both sides of the reinforcement materials were covered with bituminous mixture. Thickness, mass per unit area, tensile strength, elongation at yield, and hydraulic conductivity were used to characterize the geomembranes. Among all geomembranes, nonwoven polyester covered with 30% bitumen-70% boron waste clay mixture (PK-BTM30CW70 was found to be the most promising in terms of structure and mechanical behaviour. After that, consequences of its exposure to distilled water (DW, municipal solid waste landfill leachate (L-MSW, and hazardous waste landfill leachate (L-HW were examined to use for an innovative impermeable liner on solid waste landfills.

  4. Aggregated Computational Toxicology Online Resource

    U.S. Environmental Protection Agency — Aggregated Computational Toxicology Online Resource (AcTOR) is EPA's online aggregator of all the public sources of chemical toxicity data. ACToR aggregates data...

  5. Analysis and modeling of 3D complex modulus tests on hot and warm bituminous mixtures

    Pham, Nguyen Hoang; Sauzéat, Cédric; Di Benedetto, Hervé; González-León, Juan A.; Barreto, Gilles; Nicolaï, Aurélia; Jakubowski, Marc

    2015-05-01

    This paper presents the results of laboratory testing of hot and warm bituminous mixtures containing Reclaimed Asphalt Pavement (RAP). Complex modulus measurements, using the tension-compression test on cylindrical specimens, were conducted to determine linear viscoelastic (LVE) behavior. Sinusoidal cyclic loadings, with strain amplitude of approximately 50ṡ10-6, were applied at several temperatures (from -25 to +45 °C) and frequencies (from 0.03 Hz to 10 Hz). In addition to axial stresses and strains, radial strains were also measured. The complex modulus E ∗ and complex Poisson's ratios ν ∗ were then obtained in two perpendicular directions. Measured values in these two directions do not indicate anisotropy on Poisson's ratio. The time-temperature superposition principle (TTSP) was verified with good approximation in one-dimensional (1D) and three-dimensional (3D) conditions for the same values of shift factor. Experimental results were modeled using the 2S2P1D model previously developed at the University of Lyon/ENTPE. In addition, specific analysis showed that eventual damage created during complex modulus test is very small and is equivalent to the effect of an increase of temperature of about 0.25 °C.

  6. Contribution to physico-chemical study of Timahdit bituminous schists (Morocco): Organic matters and metalloporphyrins

    The Timahdit bituminous schists have been analysed by different methods. The experimental results obtained using these methods concern the behaviour of the schists and the Kerogen facing the pyrolysis, as well as the separation of the hydrocarbons and the metalloporphyrins. For this purpose the techniques used are: 'Rock Eval' pyrolysis, thermogravimetric analysis and electron paramagnetic resonance (E.P.R.) for the raw rock and the Kerogen; infrared (I.R.), gas chromatography and E.P.R. for the extracted organic matters; E.P.R., I.R., nuclear magnetic resonance (N.M.R.), ultraviolet (U.V.) and mass spectrometry for the metalloporphyrins identification and characterization. The analysis of these schists has shown that: We can extract per solvent only 1% of organic matters, ferric oxide hasn't any effect neither on the pyrolysis nor on the organic matters extraction and that the Kerogen of these schists are relatively rich in hydrocarbonic compounds. The gas chromatography reveal the presence of alkanes with odd number of carbons and isoprenoids. All these criteria indicate an immature, little developped organic matter which having probably a marine origin but possessing a good oil potential. It has also been observed that a part of Iron, Nickel and Vanadium in the schists are incorporated into the organic matters. Nickel and Vanadium are into macrocycles which are porphyrins. A method for extracting and separating these porphyrins has been developped. 43 figs., 21 tabs., 58 refs. (author)

  7. Influence of Extrusion Conditions on the Rheological Behavior of Nuclear Bituminized Waste Products

    In France, bitumen has been used since four decades as a container material for low/intermediate activity and long lifetime radionuclides. Industrial Bituminized Waste Products (BWP) are produced by continuous extrusion of 60 wt.% bitumen and 40 wt.% salts, in which a very small fraction is radioactive. These incorporated salts are, in majority, of two types: soluble or insoluble. During storage, the organic matrix subjected to irradiation produces gases, which can give rise to BWP swelling in the container and then to a possible overflow. The extent of gas production is directly linked to the degree of dispersion of the salts into the bitumen matrix. To quantify this dispersion, the effect of extrusion operating conditions, such as feed rate and screw speed, have been studied using a laboratory scale co-rotating twin screw extruder. BWP rheological characterization shows the development of a pseudo-solid plateau at low frequency and a change in the linear viscoelastic domain when screw speed and feed rate are varied, indicating a modification of the dispersion state. Samples characterization with environmental scanning electron microscopy (ESEM) confirms in the case of insoluble and soluble salts a change in the number of agglomerates, accompanied by an improvement of the dispersion at high screw speed but less remarkable with the feed rate. A Carreau-Yasuda law with a yield stress is proposed to describe the theological behaviour of these materials. The effects of volume fraction and maximum volume fraction on viscosity are described using a Krieger-Dougherty equation. (authors)

  8. Development of a method to determine the nuclide inventory in bituminized waste packages

    Until the 1980s, bitumen was used as a conditioning agent for weak to medium radioactive liquid waste. Its use can be ascribed mainly to the properties that indicated that the matrix was optimal. However, fires broke out repeatedly during the conditioning process, so that the method is meanwhile no longer permitted in Germany. There are an estimated 100 waste packages held by the public authorities in Germany that require a supplementary declaration. In contrast to the common matrices, such as for example resins or sludges, there is still no standardized technology for taking samples and subsequently determining the radio-nuclide for bitumen. Aspects, such as the thermoplastic behaviour, make determining the nuclide inventory more difficult in bituminized waste packages. The development of a standardized technology to take samples with a subsequent determination of the radio-nuclide analysis is the objective of a project funded by the BMBF. Known, new methods, specially developed for the project, are examined on inactive bitumen samples and then transferred to active samples. At first non-destructive methods are used. The resulting information forms an important basis to work out and apply destructive strategy for sampling and analysis. Since the project is on-going, this report can only address the development of the sampling process. By developing a sampling system, it will be possible to take samples from an arbitrary selected location of the package across the entire matrix level and thus gain representative analysis material. The process is currently being optimized. (orig.)

  9. Elemental analysis of Indonesian and Australian bituminous coal used at Kapar Power Station

    An instrumental neutron activation analytical (INAA) technique is used for the determination of thirty elements in five coal samples collected from Kapar power station, imported from Indonesia and Australia. Analyses of the samples are being associated with standards. All irradiation were performed in the nuclear reactor of Malaysia Nuclear Agency (MNA). samples were counted by Hyper Pure Germanium (HPGe) detector for short period irradiations at MNA, while for the long period irradiations the samples were counted at Universiti Kebangsaan Malaysia (UKM). The concentrations of thirty elements have been determined: The major components are Cl, Ca, Mg, K, Fe, Ti, and Na with the mean concentrations in the range between 70±69 ppm-6100±1639 ppm; and the trace elements are Zr, V, Mn, Sc, Cr, Co, As, Br, Rb, Sb, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Th, U and Ta with the mean concentrations in the range between 0.1381±0.0202 - 69.0±2.8 ppm. The results have been compared to the reported data of eight coal samples from the United States and the reported data of Australian bituminous coal. (Author)

  10. Using proximate analysis to characterize airborne dust generation from bituminous coals

    Page, S.J.; Organiscak, J.A.

    2005-11-01

    Prolonged exposure to airborne respirable coal dust is responsible for coal workers pneumoconiosis (CWP), commonly called black lung. Health research studies have identified that the prevalence and severity of CWP are directly related to both the amount of dust exposure and the coal rank. The amount of airborne respirable dust (ARD) smaller than 10 micrometers generated from breakage of different coals varies widely. To investigate the cause, researchers for the National Institute for Occupational Safety and Health (NIOSH) have conducted experiments to identify the causes of airborne respirable dust liberation. Laboratory crushing experiments were conducted on a range of low to high volatile bituminous coals from eight mines. The results indicate that the proximate analysis of a coal sample can provide a very good indicator of the potential for a dust problem. For application to the coal mining, processing, and utilization industries, data from 977 US coal seams compiled by the Department of Energy (DoE) has been used to calculate this dust generation potential from an equation based on the NIOSH measured data. A simple procedure for this calculation is provided. 1 fig.

  11. Burnout behaviour of bituminous coals in air-staged combustion conditions

    Kluger, F.; Spliethoff, H.; Hein, K.R.G. [University of Stuttgart, Stuttgart (Germany). Inst. of Process Engineering and Power Plant (IVD)

    2001-07-01

    In order to determine the influence on burnout by the combustion conditions and the coal preparation, three bituminous coals sold on the world market, from three different locations in Poland, South Africa, and Australia, were studied more closely. For this purpose, the coals were ground in two different particle size ranges, which, besides the influence of the combustion conditions, such a temperature, residence time, and stoichiometry, made it possible to also investigate the impact on burnout by the coal preparation. The experiments were carried out in an electrically heated entrained-flow reactor with a thermal input of 8.5 kW. The parameters for the experiments are wall temperature (1000-1350{degree}C), air ratio (0.6-1.15) and two particle sizes (70% {lt} 75 {mu}m, 90% {lt} 75 {mu}m). The results show that in general, for increasing temperatures, the burnout quality will improve. For the Australian Illawara coal, another outcome is increased NOx emissions. Lowering the air ratio in the reduction zone leads to less NOx emission but to increased unburnt matter in ash. For the smaller particle size fraction, the analysis of the different particle sizes shows an improvement of the burnout without a change in NOx emissions. 10 refs., 10 figs., 2 tabs.

  12. Protein Colloidal Aggregation Project

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    To investigate the pathways and kinetics of protein aggregation to allow accurate predictive modeling of the process and evaluation of potential inhibitors to prevalent diseases including cataract formation, chronic traumatic encephalopathy, Alzheimer's Disease, Parkinson's Disease and others.

  13. Platelet activation and aggregation

    Jensen, Maria Sander; Larsen, O H; Christiansen, Kirsten; Fenger-Eriksen, C; Ingerslev, J; Sørensen, Benny

    2013-01-01

    This study introduces a new laboratory model of whole blood platelet aggregation stimulated by endogenously generated thrombin, and explores this aspect in haemophilia A in which impaired thrombin generation is a major hallmark. The method was established to measure platelet aggregation initiated...... by tissue factor evaluated by means of impedance aggregometry. Citrated whole blood from healthy volunteers and haemophilia A patients with the addition of inhibitors of the contact pathway and fibrin polymerization was evaluated. In healthy persons, a second wave of platelet aggregation was found to...... coincide with the thrombin burst and to be abolished by thrombin inhibitors. In this system, platelet aggregation in severe haemophilia A (n = 10) was found to be significantly decreased as compared with healthy individuals (912 ± 294 vs. 1917 ± 793 AU × min, P = 0.003), most probably due to the weak level...

  14. Recycled aggregates concrete: aggregate and mix properties

    González-Fonteboa, B.

    2005-09-01

    Full Text Available This study of structural concrete made with recycled concrete aggregate focuses on two issues: 1. The characterization of such aggregate on the Spanish market. This involved conducting standard tests to determine density, water absorption, grading, shape, flakiness and hardness. The results obtained show that, despite the considerable differences with respect to density and water absorption between these and natural aggregates, on the whole recycled aggregate is apt for use in concrete production. 2. Testing to determine the values of basic concrete properties: mix design parameters were established for structural concrete in non-aggressive environments. These parameters were used to produce conventional concrete, and then adjusted to manufacture recycled concrete aggregate (RCA concrete, in which 50% of the coarse aggregate was replaced by the recycled material. Tests were conducted to determine the physical (density of the fresh and hardened material, water absorption and mechanical (compressive strength, splitting tensile strength and modulus of elasticity properties. The results showed that, from the standpoint of its physical and mechanical properties, concrete in which RCA accounted for 50% of the coarse aggregate compared favourably to conventional concrete.

    Se aborda el estudio de hormigones estructurales fabricados con áridos reciclados procedentes de hormigón, incidiéndose en dos aspectos: 1. Caracterización de tales áridos, procedentes del mercado español. Para ello se llevan a cabo ensayos de densidad, absorción, granulometría, coeficiente de forma, índice de lajas y dureza. Los resultados obtenidos han puesto de manifiesto que, a pesar de que existen diferencias notables (sobre todo en cuanto a densidad y absorción con los áridos naturales, las características de los áridos hacen posible la fabricación de hormigones. 2. Ensayos sobre propiedades básicas de los hormigones: se establecen parámetros de dosificaci

  15. Coagulation with limited aggregations

    Bertoin, Jean

    2012-01-01

    Smoluchowski's coagulation equations can be used as elementary mathematical models for the formation of polymers. We review here some recent contributions on a variation of this model in which the number of aggregations for each atom is a priori limited. Macroscopic results in the deterministic setting can be explained at the microscopic level by considering a version of stochastic coalescence with limited aggregations, which can be related to the so-called random configuration model of random graph theory.

  16. The Aggregation Dilemma

    Ingmar Schumacher

    2014-01-01

    The results in this paper show that the level of aggregation used in a social welfare func- tion matters significantly for policy analysis. Using climate change as an example, it is shown that, under the mild and widely-accepted assumptions of asymmetric climate change impacts and declining marginal utility, an aggregation dilemma may arise that dwarfs most other policy-relevant aspects in the climate change cost-benefit analysis. Estimates based on the RICE-99 model (Nordhaus and Boyer 2000)...

  17. Glycine reduces platelet aggregation

    Schemmer, Peter; Zhong, Zhi; Galli, Uwe; Wheeler, Michael D.; Xiangli, Li; Bradford, Blair U.; Conzelmann, Lars O.; Forman, Dow; Boyer, José; Thurman, Ronald G

    2012-01-01

    It has been demonstrated that a wide variety of white blood cells and macrophages (i.e. Kupffer cells, alveolar and peritoneal macrophages and neutrophils) contain glycine-gated chloride channels. Binding of glycine on the receptor stimulates Cl− influx causing membrane hyperpolarization that prevents agonist-induced influx of calcium. Since platelet-aggregation is calcium-dependent, this study was designed to test the hypothesis that glycine would inhibit platelet aggregation. Rats were fed ...

  18. Development of refilling techniques of LA-type bituminized waste products

    In JAEA, 13,296 drums of low-radioactivity bituminized waste products (BWPs) have been stored in asphalt solidification storages. In order to effectively utilize the space of the BWP in a repository site, refilling techniques of the BWP from the drum to a box-shaped container were studied. Tentative processes, which we devised, consisted of (1) take-off of BWP from the drum, (2) separation of a post filling part from BWP and (3) refilling of BWP to a box-shaped container. Two methods for each process were selected, and work efficiencies of the methods were investigated by using a synthetic BWP. (1) Two take-off methods: one was falling down of the BWP from the drum at high temperature such as 100°C and 150°C, and the other was removing the cut drum from the BWP at low temperature. In the former case, it was found that at least 20wt% of the BWP was attached on the container. In the latter case, ca. 100wt% of the BWP was easily recovered by cutting and peeling the drum below 10°C. (2) Two separation methods: one was cutting off the post filling part by using a flat blade, and the other was crushing the post filling part by using a mechanical hammer. In the former case, the BWP could be cut in 2 h, but it was observed that some BWP was attached on the blade. In the latter case, it was found that the post filling part was easily crushed from the BWP below 0°C. (3) Two filling methods: one was filling the softened BWP by heating, and the other was pressure filling. In the both method, filling rates of the BWP were 100wt% and 98.8wt%, respectively. Volume of the BWP after the filling tests increased 6vol% and 2vol% compared to theoretical volume, respectively. (author)

  19. Study on the submicron and micron morphology and the properties of poor bituminous coal burnout

    Pei-Fang Fu; Huai-Chun Zhou; Qing-Yan Fang; Hai Yao; Jianrong Qiu; Minghou Xu [Huazhong University of Science and Technology, Wuhan (China). State Key Laboratory of Coal Combustion

    2007-05-15

    Carbon burnout and its reaction mechanism have been widely focused on in the past decades. The properties of burnout, submicron and micron morphology and the reaction mechanism of poor bituminous coal/char (PBC) in a W-shaped power plant boiler was studied and was compared with those in DTF and in TGA, which showed that the degree of PBC burnout in TGA at 1450{sup o}C was greater than or approximately equal to that in a W-shaped boiler, and that the complexity of the reactions among residual char, oxygen and SiO{sub 2} did not seem to result in mass loss in TGA, although the weight percentage of the residual char in ash decreased from 33% ad (air dry basis) at 900{sup o}C to 9% and at 1450{sup o}C. According to the distribution of pores and the properties of the char burnout, the char can be simply categorized into three classes: char burnout easy, char burnout difficult and char burnout very difficult. The differences of the reaction mechanism must be considered while predicting the burning rate and degree of char burnout in a full-scale boiler by making use of experimental results from TGA and DTF. A different char particle contains markedly different amount of carbons, but for a special char particle, the ratio of carbon to ash is generally constant, and an ash shell does not exist on the char surface. The fusion mineral matter composing of C-O-Si-Al is amorphous, not in the form of Al{sub 2}O{sub 3} and SiO{sub 2} above 1450{sup o}C.

  20. Mercury speciation and distribution in a 660-megawatt utility boiler in Taiwan firing bituminous coals.

    Hsi, Hsing-Cheng; Lee, Hsiu-Hsia; Hwang, Jyh-Feng; Chen, Wang

    2010-05-01

    Mercury speciation and distribution in a 660-MW tangential-fired utility boiler in Taiwan burning Australian and Chinese bituminous coal blends was investigated. Flue gases were simultaneously sampled at the selective catalytic reduction (SCR) inlet, the SCR outlet, the electrostatic precipitator (ESP) outlet, and the stack. Samplings of coal, lime, bottom ash/slag, fly ash, and gypsum slurry were also conducted. Results indicated that flue gases at the inlet to SCR contained a great potion of particle-bound mercury (Hg(p)), 59-92% of the total mercury. Removal of mercury was not observed for the SCR system. However, repartitioning of mercury species across the SCR occurred that significantly increased the portion of elemental mercury (Hg0) to up to 29% and oxidized mercury (Hg2+) to up to 33% in the SCR outlet gas. Overreporting of Hg(p) at the inlet of SCR may cause the observed repartitioning; the high ammonia/nitric oxide circumstance in the SCR unit was also speculated to cause the mercury desorption from ash particles and subsequent reentrance into the gas phase. ESP can remove up to 99% of Hg(p), and wet flue gas desulfurization (FGD) can remove up to 84% of Hg2+. Mercury mass balances were calculated to range between 81 and 127.4%, with an average of 95.7% wherein 56-82% was in ESP fly ash, 8.7-18.6% was retained in the FGD gypsum, and 6.2-26.1% was emitted from the stack. Data presented here suggest that mercury removal can be largely enhanced by increasing the conversion of Hg0 into Hg(p) and Hg2+. PMID:20480850

  1. Development of new non destructive methods for bituminized radioactive waste drums characterization

    Radioactive waste constitute a major issue for the nuclear industry. One of the key points is their characterization to optimize their management: treatment and packaging, orientation towards the suited disposal. This thesis proposes an evaluation method of the low-energy photon attenuation, based on the gamma-ray spectra Compton continuum. Effectively, the 241Am measurement by gamma-ray spectrometry is difficult due to the low energy of its main gamma-ray (59.5 keV). The photon attenuation strongly depends on the bituminous mix composition, which includes very absorbing elements. As the Compton continuum also depends on this absorption, it is possible to link the 59.5 keV line attenuation to the Compton level. Another technique is proposed to characterize uranium thanks to its fluorescence X-rays induced by the gamma emitters already present in the waste. The uranium present in the drums disturbs the neutron measurements and its measurement by self-induced X-ray fluorescence allows to correct this interference. Due to various causes of error, the total uncertainty is around 50 % on the activity of the radioisotope 241Am, corrected by the peak to Compton technique. The same uncertainty is announced on the uranium mass measured by self induced X-ray fluorescence. As a consequence of these promising results, the two methods were included in the industrial project of the 'Marcoule Sorting Unit'. One major advantage is that they do not imply any additional material because they use information already present in the gamma-ray spectra. (author)

  2. Sorbent Injection for Small ESP Mercury Control in Low Sulfur Eastern Bituminous Coal Flue Gas

    Carl Richardson; Katherine Dombrowski; Douglas Orr

    2006-12-31

    This project Final Report is submitted to the U.S. Department of Energy (DOE) as part of Cooperative Agreement DE-FC26-03NT41987, 'Sorbent Injection for Small ESP Mercury Control in Low Sulfur Eastern Bituminous Coal Flue Gas.' Sorbent injection technology is targeted as the primary mercury control process on plants burning low/medium sulfur bituminous coals equipped with ESP and ESP/FGD systems. About 70% of the ESPs used in the utility industry have SCAs less than 300 ft2/1000 acfm. Prior to this test program, previous sorbent injection tests had focused on large-SCA ESPs. This DOE-NETL program was designed to generate data to evaluate the performance and economic feasibility of sorbent injection for mercury control at power plants that fire bituminous coal and are configured with small-sized electrostatic precipitators and/or an ESP-flue gas desulfurization (FGD) configuration. EPRI and Southern Company were co-funders for the test program. Southern Company and Reliant Energy provided host sites for testing and technical input to the project. URS Group was the prime contractor to NETL. ADA-ES and Apogee Scientific Inc. were sub-contractors to URS and was responsible for all aspects of the sorbent injection systems design, installation and operation at the different host sites. Full-scale sorbent injection for mercury control was evaluated at three sites: Georgia Power's Plant Yates Units 1 and 2 [Georgia Power is a subsidiary of the Southern Company] and Reliant Energy's Shawville Unit 3. Georgia Power's Plant Yates Unit 1 has an existing small-SCA cold-side ESP followed by a Chiyoda CT-121 wet scrubber. Yates Unit 2 is also equipped with a small-SCA ESP and a dual flue gas conditioning system. Unit 2 has no SO2 control system. Shawville Unit 3 is equipped with two small-SCA cold-side ESPs operated in series. All ESP systems tested in this program had SCAs less than 250 ft2/1000 acfm. Short-term parametric tests were conducted on Yates

  3. Sustainable Concrete with Recycled Aggregate

    Kara, P

    2012-01-01

    Concretes produced with recycled aggregates are the subject of several papers recently published in the technical literature. Substitution of natural aggregates can be one of possibilities to take care of landfills and increase of CO2 emissions into the atmosphere in Latvia. Recycled aggregate is a valuable resource; value-added consumption of recycled aggregate, as replacement for virgin aggregate in concrete, can yield significant energy and environmental benefits. In present study recycled...

  4. Arrow's Theorem in Judgement Aggregation

    Franz Dietrich; Christian List

    2005-01-01

    In response to recent work on the aggregation of individual judgements on logically connected propositions into collective judgements, it is often asked whether judgement aggregation is a special case of Arrowian preference aggregation. We argue the opposite. After proving a general impossibility theorem, we construct an embedding of preference aggregation into judgement aggregation and prove Arrow's theorem as a corollary of our result. Although we provide a new proof of Arrow's theorem, our...

  5. Absorption Spectra of Astaxanthin Aggregates

    Olsina, Jan; Durchan, Milan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption...

  6. Aggregate Oligopoly Games with Entry

    Anderson, Simon P.; Erkal, Nisvan; Piccinin, Daniel

    2013-01-01

    We use cumulative reaction functions to compare long-run market structures in aggregative oligopoly games. We first compile an IO toolkit for aggregative games. We show strong neutrality properties across market structures. The aggregator stays the same, despite changes in the number of firms and their actions. The IIA property of demands (CES and logit) implies that consumer surplus depends on the aggregator alone, and that the Bertrand pricing game is aggregative. We link together the follo...

  7. Aggregation on heterogeneous surface

    Lu Hang-Jun; Wu Feng-Min; Fang Yun-Zhang

    2004-01-01

    Chessboard-like substrates are introduced in this paper, in order to study the diffusion-limited aggregation (DLA)and the motion of poly-atoms on heterogeneous surfaces. The effect of morphology of such substrates upon the cluster aggregation is investigated using the Monte Carlo simulation. It is found that the growth process and the cluster morphology are governed by the energetic topography of the substrates. Our simulation also indicate that the island density and the fractal dimension of the clusters depend strongly on the substrate topography and the activation energy.

  8. DEVELOPMENT OF TEST PROTOCOLS FOR THE ANALYSIS OF MAGNETO-RHEOLOGICAL PROPERTIES OF FIELD-RESPONSIVE BITUMINOUS BINDERS

    Ezio Santagata

    2014-01-01

    Full Text Available Magneto-rheological fluids are materials that exhibit a significant change in their rheological properties in the presence of a magnetic field. Because of such a field-dependent behavior, they can act as smart materials in applications in which changeable performances are desired. In road pavement engineering, the use of bitumen-based magneto-rheological fluids may open innovative scenarios related to the construction of smart pavement sections and to the investigation of damage mechanisms in binders and mixtures. The research work presented in this study explored magneto-rheological properties of several field-responsive bituminous binders obtained from two different base bitumens combined with multi-wall carbon nanotubes and powder iron. The experimental program included oscillatory shear loading tests at different temperatures, performed in the strain controlled mode by means of a dynamic shear rheometer equipped with a magneto-rheological device. The investigation was carried out with the specific goal of identifying critical issues which should be taken into account in materials preparation, testing procedures and data analysis. Undesired overheating of specimens during testing was identified and taken into account for a correct interpretation of experimental data. Thus, while the field-sensitivity of carbon nanotubes was found to be negligible as a result of the magnetic shielding action of bitumen, it was shown that powder iron can significantly affect the magneto-rheological properties of bituminous binders when employed in sufficiently high amounts. Moreover, obtained results indicated that selection of base bitumen is a key factor in designing bituminous-based smart materials. Practical implications which derive from the study are mainly relative to the fine-tuning of laboratory characterization procedures which should necessarily overcome current limitations in temperature regulation and magnetic field generation. Experimental data

  9. Assessment of 137Cs and 90Sr leachate rate from bituminous radioactive wastes in surface soil disposal

    Experimental disposal of tested bitumen units with 107 Bq/kg 137Cs and 90Sr specific activity in surface soil was conducted to evaluate environmental impact of bituminized radioactive wastes. Calculations of volume integral were carried out using computer. Due to determination of integral numerical value it was founded, that 1.6x108 Bq enter soil from the unit during 10 years. The obtained value may be used as normalizing parameter at simulation of radionuclide leaching from monolithic forms as well as for correct selection of boundary conditions in dispersion equation at simulation of radioactive contamination migration

  10. Petrographic and Vitrinite Reflectance Analyses of a Suite of High Volatile Bituminous Coal Samples from the United States and Venezuela

    Hackley, Paul C.; Kolak, Jonathan J.

    2008-01-01

    This report presents vitrinite reflectance and detailed organic composition data for nine high volatile bituminous coal samples. These samples were selected to provide a single, internally consistent set of reflectance and composition analyses to facilitate the study of linkages among coal composition, bitumen generation during thermal maturation, and geochemical characteristics of generated hydrocarbons. Understanding these linkages is important for addressing several issues, including: the role of coal as a source rock within a petroleum system, the potential for conversion of coal resources to liquid hydrocarbon fuels, and the interactions between coal and carbon dioxide during enhanced coalbed methane recovery and(or) carbon dioxide sequestration in coal beds.

  11. Aggregates, broccoli and cauliflower

    Grey, Francois; Kjems, Jørgen K.

    1989-09-01

    Naturally grown structures with fractal characters like broccoli and cauliflower are discussed and compared with DLA-type aggregates. It is suggested that the branching density can be used to characterize the growth process and an experimental method to determine this parameter is proposed.

  12. Diffusion in aggregated soil.

    Rappoldt, C.

    1992-01-01

    The structure of an aggregated soil is characterized by the distribution of the distance from an arbitrary point in the soil to the nearest macropore or crack. From this distribution an equivalent model system is derived to which a diffusion model can be more easily applied. The model system consist

  13. Behaviour of bituminized waste under gamma irradiation. Effect of STE3 decontamination process components

    Liquid wastes of light and medium activity are treated by chemical co-precipitation and sludge are mixed with bitumen. Irradiation is responsible of gas production and potential swelling of the embedded. It prevails on limitation of filling of storage containers and activity to 140 Ci. The aim of this work is the study of influence of the components of the decontamination process on the behaviour of bituminous wastes, in order to control swelling and to state radiolysis mechanisms, both for production and storage of wastes. For pure bitumen, mechanism of production of H2 and CH4 are specified. Oxygen consumption, localised on the surface of samples, leads to conversion of aromatic oils and resins to asphaltenes, by a chain reaction mechanism. CO2 et CO are reaction products of gaseous oxygen, respectively with bitumen and light hydrocarbons. The composition of bitumen is slightly modified to heavier and higher polarity products, with parallel hardening. NaNO3, Na2SO4, BaSO4, PPFNi, K2SO4, NiSO4, et diatoms DIT3R et DIC3 have strictly a dilution effect towards gas generation. CoS, above 1% embedded, strongly inhibits production of H2, CH4 and light hydrocarbons. Degradation of bitumen being reduced, a radical mechanism with both radicals H· et R· might exist. Kinetic shows that a bi-radicals mechanism (or more) is probable. In the same way, Raney's nickel induces a important decrease of production of H2, CH4 et C2, with a capacity of 7,7 ml/g. Swelling depends on dimension of sample gas production and dose rate. Solid content and particle size are not determining parameters. Low swelling is obtained for penetrability higher than 70 1/10 mm, This can be realised by addition of a solvent as TBP and by increasing temperature above 40 deg C. Rheological characterizations (oscillation and creeping mode) have not been successful to correlate swelling with a physical parameter. (author)

  14. Mechanical, sorption and transport experiments on a German high volatile bituminous coal

    Gensterblum, Y.; Krooss, B.M. [RWTH Aachen Univ. (Germany). Inst. of Geology and Geochemistry of Petroleum and Coal; Massarotto, Paul [Queensland Univ., Brisbane, St Lucia, QLD (Australia). School of Engineering

    2013-08-01

    A high volatile bituminous coal (vitrinite reflectance: 0.93%, carbon content: 83%) from the Prosper-Haniel mine, North Rhine-Westphalia has been studied using a comprehensive set of measurements and experimental procedures at RWTH Aachen University and the University of Queensland. Using the True Triaxial Stress Coal Permeameter (TTSCP) (Massarotto 2003) of the University of Queensland, permeability and gas displacement tests were performed on an 80 mm cube of the Prosper-Haniel coal. Extensive data sets were recorded to assess the effects of stress changes on gas transport and the impact of nitrogen, methane and CO{sub 2} sorption on the mechanical properties. We investigate the permeability coefficients for helium, nitrogen, methane and carbon dioxide measured on this sample as a function of net stress. As expected, permeability values decrease with increasing stress. Methane and nitrogen have nearly identical permeability coefficients throughout the entire net stress range, while permeability coefficients measured with helium are higher and those measured with CO{sub 2} significantly lower. During the permeability measurements with CO{sub 2} an anisotropic swelling of the coal cube by about 0.19% to 0.23% was observed. The volumetric effect (swelling) is 100 times slower than gas displacement. Simultaneous mechanical tests indicated a softening of the coal block upon exposure to CO{sub 2}. Thus, a decrease of Young's modulus (YM) of the coal cube during the CO{sub 2} flow test was observed as compared to the methane and nitrogen tests. High-pressure sorption isotherms with CH{sub 4} and CO{sub 2} were determined on different grain-size fractions of the Prosper-Haniel coal at 318K and different moisture contents. Methane sorption capacity decreases by 29% with increasing moisture content. Also, a decrease of sorption rate was observed with increasing moisture content. While sorption rates are generally faster for CO{sub 2} than for CH{sub 4}, the sorption

  15. Organic geochemistry of Upper Carboniferous bituminous coals and clastic sediments from the Lublin Coal Basin

    Gola, Marek R.; Karger, Michał; Gazda, Lucjan; Grafka, Oliwia

    2013-09-01

    Bituminous coals and clastic rocks from the Lublin Formation (Pennsylvanian, Westphalian B) were subjected to detailed biomarker and Rock-Eval analyses. The investigation of aliphatic and aromatic fractions and Rock-Eval Tmax suggests that the Carboniferous deposits attained relatively low levels of thermal maturity, at the end of the microbial processes/initial phase of the oil window. Somewhat higher values of maturity in the clastic sediments were caused by postdiagenetic biodegradation of organic matter. The dominance of the odd carbon-numbered n-alkanes in the range n-C25 to n-C31 , high concentrations of moretanes and a predominance of C 28 and C29 steranes are indicative of a terrigenous origin of the organic matter in the study material. This is supported by the presence of eudesmane, bisabolane, dihydro-ar-curcumene and cadalene, found mainly in the coal samples. In addition, tri- and tetracyclic diterpanes, e. g. 16β(H)-kaurane, 16β(H)-phyllocladane, 16α(H)-kaurane and norisopimarane, were identified, suggesting an admixture of conifer ancestors among the deposited higher plants. Parameters Pr/n-C17 and Rdit in the coal samples show deposition of organic matter from peat swamp environments, with the water levels varying from high (water-logged swamp) to very low (ephemeral swamp). Clastic deposits were accumulated in a flood plain environment with local small ponds/lakes. In pond/lake sediments, apart from the dominant terrigenous organic matter, research also revealed a certain quantity of algal matter, indicated, i.a., by the presence of tricyclic triterpanes C28 and C29 and elevated concentrations of steranes. The Paq parameter can prove to be a useful tool in the identification of organic matter, but the processes of organic matter biodegradation observed in clastic rocks most likely influence the value of the parameter, at the same time lowering the interpretation potential of these compounds. The value of Pr/Ph varies from 0.93 to 5.24 and from 3

  16. Rheological behaviour of polymer-modified bituminous mastics : a comparative analysis between physical and chemical modification

    Shivokhin, Maxim; García Morales, Moisés; Partal López, Pedro; Cuadri Vega, Antonio Abad; Gallegos Montes, Críspulo

    2012-01-01

    Mastic, a bitumen/filler blend which naturally forms when bitumen is mixed with aggregates is the actual product used to bind coarse mineral particles in the asphalt mixtures. As a result, the characterisation of mastics is essential to improve the understanding of the response and performance of asphalt concrete pavements. On the other hand, the lack of experimental data concerning the behaviour of mastics and, above all, polymer-modified mastics has been lately claimed. In that sense, this ...

  17. Characterization of burning and CO2 gasification of chars from mixtures of Zonguldak (Turkey) and Australian bituminous coals

    In this study, different mixtures (30 wt.% + 70 wt.% and 50 wt.% + 50 wt.%, respectively) of Zonguldak bituminous coal (Turkey) and an Australian bituminous coal are carbonized to obtain char samples. The ignition temperatures of the samples are determined by sending O2 onto the samples in a system designed for determining the ignition temperature. The gasification reactivity of the chars in a CO2 atmosphere is also measured at temperatures between 800 deg. C and 1050 deg. C. The relationship between the ignition temperature and the burning character of the same samples is investigated thermogravimetrically. The moisture, ash and volatile matter analyses are also performed. An increase in carbonization temperature leads to a decrease in the amount of volatile matter. The differences between the effects of volatile matter on the ignition temperature and the gasification reactivity of the samples with CO2 might be explained by the change in pore structure and the varying catalytic effect of mineral components in the structure. It is also seen that there is a good correlation between the thermal analysis and the complete analysis results of the samples

  18. Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

    Riaza Benito, Juan; Khatami, Reza; Levendis, Yiannis A.; Álvarez González, Lucía; Gil Matellanes, María Victoria; Pevida García, Covadonga; Rubiera González, Fernando; Pis Martínez, José Juan

    2014-01-01

    A fundamental investigation has been conducted on the combustion behavior of single particles (75–150 μm) of four coals of different ranks: anthracite, semi-anthracite, medium-volatile bituminous and high-volatile bituminous. A laboratory-scale transparent laminar-flow drop-tube furnace, electrically-heated to 1400 K, was used to burn the coals. The experiments were performed in different combustion atmospheres: air (21%O2/79%N2) and four simulated dry oxy-fuel conditions: 21%O2/79%CO2, 30%O2...

  19. Aggregation Algorithms in Heterogeneous Tables

    Titus Felix FURTUNA; Ivan, Ion; Marian DARDALA

    2006-01-01

    The heterogeneous tables are most used in the problem of aggregation. A solution for this problem is to standardize these tables of figures. In this paper, we proposed some methods of aggregation based on the hierarchical algorithms.

  20. ASSESSMENT OF RECYCLED AGGREGATE CONCRETE

    Ahmad Mujahid Ahmad Zaidi

    2009-01-01

    Used of recycled aggregate (RA) in concrete can be described in environmental protection and economical terms. The application of recycled aggregate to use in construction activities have been practice by developed European countries and also of some Asian countries. This paper reports the results of an experimental study on the mechanical properties of recycled aggregate concrete (RAC) as compared to natural aggregate concrete (NAC). The effects of size of RA on compressive strength were dis...

  1. Judgement aggregation and distributed thinking

    Spiekermann, Kai

    2010-01-01

    In recent years, judgement aggregation has emerged as an important area of social choice theory. Judgement aggregation is concerned with aggregating sets of individual judgements over logically connected propositions into a set of collective judgements. It has been shown that even seemingly weak conditions on the aggregation function make it impossible to find functions that produce rational collective judgements from all possible rational individual judgements. This implies...

  2. Aggregating governance indicators

    Kaufmann, Daniel; Kraay, Aart; Zoido-Lobaton, Pablo

    1999-01-01

    In recent years the growing interest of academics and policymakers in governance has been reflected in the proliferation of cross-country indices measuring various aspects of governance. The authors explain how a simple variant of an unobserved components model can be used to combine the information from these different sources into aggregate governance indicators. The main advantage of this method us that it allows quantification of the precision of both individual sources of governance data...

  3. Study of Recycled Concrete Aggregates

    Jitender Sharma; Sandeep Singla

    2014-01-01

    This paper describes the introduction and production of recycled concrete aggregates and its various applications in the construction industry. In this paper, properties of recycled aggregates and its comparison with the natural aggregates are also mentioned. Future recommendations about RCA are also included.

  4. Proteins aggregation and human diseases

    Hu, Chin-Kun

    2015-04-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  5. Absorption Spectra of Astaxanthin Aggregates

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  6. Petrography and geochemistry of Oligocene bituminous coal from the Jiu Valley, Petrosani basin (southern Carpathian Mountains), Romania

    Belkin, Harvey E.; Tewalt, Susan J. [U.S. Geological Survey, 956 National Center, Reston, VA 20192 (United States); Hower, James C. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); Stucker, J.D. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); University of Kentucky Department of Earth and Environmental Sciences, Lexington, KY 40506 (United States); O' Keefe, Jennifer M.K. [Morehead State University, Morehead, KY, 40351 (United States); Tatu, Calin A. [University of Medicine and Pharmacy, Department of Immunology, Clinical Laboratory No. 1, Pta. E. Murgu No. 2, RO-1900 Timisoara (Romania); Buia, Grigore [University of Petrosani, Department of Geology, University St. 20, RO-2675 Petrosani (Romania)

    2010-05-01

    Belt samples of Oligocene (Chattian) bituminous coal from 10 underground mines located in the Jiu Valley, Hunedoara County, Petrosani basin, Romania, have been examined and analyzed for proximate and ultimate analysis, major-, minor- and trace-element chemistry, organic petrography, and vitrinite reflectance. The mineral chemistry and mode of occurrence of trace elements also have been investigated using SEM and electron microprobe techniques. Twenty coal beds occur in the Jiu Valley and most of the samples are from bed no. 3, the most productive bed of the Dilja-Uricani Formation of Oligocene age. The Petrosani basin, oriented SW-NE, is 48-km long, 10-km wide at the eastern part and 2-km wide at the western part. The coal mines are distributed along the center of the valley generally following the Jiu de Vest River. Reflectance measurements indicate that the rank of the coals ranges from high-volatile B to high-volatile A bituminous. Overall, rank decreases from the southwest to the northeast. In bed no. 3, R{sub max} varies from 0.75% in the northeast to 0.93% in the southwest. Although, most Oligocene coals in Romania and adjacent countries are lignite in rank, the Jiu Valley bituminous coals have been affected by regional metamorphism and attending hydrothermal fluids related to the Alpine orogenic event. The coals are all dominated by vitrinite; resinite and funginite are important minor macerals in most of the coals. Pyrite and carbonate generally dominate the mineral assemblages with carbonate more abundant in the northwest. Siderite occurs as nodules and masses within the macerals (generally vitrinite). Dolomite and calcite occur as fracture fillings, plant-cell fillings, and in other authigenic forms. Late-stage fracture fillings are siderite, dolomite, calcite, and ankerite. In one instance, two populations of siderite ({proportional_to} 35 and {proportional_to} 45 wt.% FeO) plus ankerite fill a large fracture. Late-stage pyrite framboid alteration is Ni

  7. Dependence of carbon dioxide sorption on the petrographic composition of bituminous coals from the Czech part of the Upper Silesian Basin, Czech Republic

    Weishauptová, Zuzana; Sýkorová, Ivana

    2011-01-01

    Roč. 90, č. 1 (2011), s. 312-323. ISSN 0016-2361 R&D Projects: GA ČR GA106/08/1146; GA AV ČR IAA300460804 Institutional research plan: CEZ:AV0Z30460519 Keywords : bituminous coal * sorption capacity * maceral composition Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.248, year: 2011

  8. Effect of structural alteration on the macromolecular properties of brown and bituminous coals, quantitative relationships to the hydrogenation reactivity with tetralin

    Kuznetsov, P.N.; Kuznetsova, L.I. [Inst. of Chemistry and Chemico-Metallurgical Processes, Krasnoyarsk (Russian Federation); Bimer, J.; Salbut, P.D. [Inst. of Organic Chemistry, Warszawa (Poland); Gruber, R. [Univ. de Metz (France)

    1996-12-31

    The mobility of macromolecular network has been found to be the fundamental property of both brown and bituminous coals governing the reactivity for hydrogenation with tetralin. In Kansk-Achinsk brown coal, this was primarily affected by carboxylate cross-linking via polyvalent cations like Ca.

  9. Aggregate Demand and Supply

    Farmer, Roger E.A.

    2007-01-01

    This paper is part of a broader project that provides a microfoundation to the General Theory of J.M. Keynes. I call this project 'old Keynesian economics' to distinguish it from new-Keynesian economics, a theory that is based on the idea that to make sense of Keynes we must assume that prices are sticky. I describe a multi-good model in which I interpret the definitions of aggregate demand and supply found in the General Theory through the lens of a search theory of the labor market. I argue...

  10. Aggregation of smooth preferences

    Norman Schofield

    1998-01-01

    Suppose p is a smooth preference profile (for a society, N) belonging to a domain PN. Let be a voting rule, and (p)(x) be the set of alternatives in the space, W, which is preferred to x. The equilibrium E((p)) is the set {x∈W:(p)(x) is empty}. A sufficient condition for existence of E((p)) when p is convex is that a "dual", or generalized gradient, d(p)(x), is non-empty at all x. Under certain conditions the dual "field", d(p), admits a "social gradient field" (p). is called an "aggregator" ...

  11. Concrete = aggregate, cement, water?

    Concrete for the Temelin nuclear power plant is produced to about 70 different formulae. For quality production, homogeneous properties of aggregates, accurate proportioning devices, technological discipline and systematic inspections and tests should be assured. The results are reported of measuring compression strength after 28 days for different concrete samples. The results of such tests allow reducing the proportion of cement, which brings about considerable savings. Reduction in cement quantities can also be achieved by adding ash to the concrete mixes. Ligoplast, a plasticizer addition is used for improving workability. (M.D). 8 figs

  12. Comparative study of thermal properties of bio-coal from aromatic spent with low rank sub-bituminous coals.

    Yadav, Vineet; Baruah, B P; Khare, Puja

    2013-06-01

    In present investigation, biocoal samples were prepared from aromatic plant waste of two perennial grasses, i.e. Cymbopogon flexuosus (lemongrass) and Vetiveria zizanioides (khus) after oil extraction, root of Rosa damascene (rose), bark of Eucalyptus citriodora. These biocoals were characterized by proximate, ultimate, metal, thermogravimetric analysis (TGA), Fourier Transform Infra Red (FTIR) spectroscopy and ash analyses. Activation energies, initial temperature of devolatilization, maximum rate of weight loss (Rmax), fouling, slagging and alkali index were determined on the basis of TGA and ash analysis. These biocoals have good calorific values. There is possibility of slagging and fouling in combustion system but it is not severe. Owing to their similar fuel properties as high sulphur sub-bituminous coal, they can be good candidates for co-firing. Blending of these biocoals with high sulphur coals will serve dual purpose as (i) alternate fuel, and (ii) reduction in SO2 emission. PMID:23603187

  13. Combustion characteristics of Malaysian oil palm biomass, sub-bituminous coal and their respective blends via thermogravimetric analysis (TGA).

    Idris, Siti Shawalliah; Rahman, Norazah Abd; Ismail, Khudzir

    2012-11-01

    The combustion characteristics of Malaysia oil palm biomass (palm kernel shell (PKS), palm mesocarp fibre (PMF) and empty fruit bunches (EFB)), sub-bituminous coal (Mukah Balingian) and coal/biomass blends via thermogravimetric analysis (TGA) were investigated. Six weight ratios of coal/biomass blends were prepared and oxidised under dynamic conditions from temperature 25 to 1100°C at four heating rates. The thermogravimetric analysis demonstrated that the EFB and PKS evolved additional peak besides drying, devolatilisation and char oxidation steps during combustion. Ignition and burn out temperatures of blends were improved in comparison to coal. No interactions were observed between the coal and biomass during combustion. The apparent activation energy during this process was evaluated using iso-conversional model free kinetics which resulted in highest activation energy during combustion of PKS followed by PMF, EFB and MB coal. Blending oil palm biomass with coal reduces the apparent activation energy value. PMID:22944493

  14. Effect of oxidation on the chemical nature and distribution of low-temperature pyrolysis products from bituminous coal

    Furimsky, E.; MacPhee, J.A.; Vancea, L.; Ciavaglia, L.A.; Nandi, B.N.

    1983-04-01

    Two bituminous coals, a high volatile Eastern Canadian and a medium volatile Western Canadian, were used to investigate the effect of oxidation on yields and chemical composition of gases, liquids and chars produced during coal pyrolysis. Pyrolysis experiments were performed at 500 C using the Fischer assay method. Mild oxidation of coals resulted in a decrease of liquid hydrocarbon yields. Further coal oxidation increased the proportion of aromatic carbon in liquid products as determined by N.M.R. and also increased the content of oxygen in liquid products. The content of oxygen in chars was markedly lower than in corresponding coals. An attempt is made to explain reactions occurring during oxidation and subsequent pyrolysis of coal on the basis of differences in chemical composition of gases, liquids and chars. (19 refs.)

  15. Effect of oxidation on the chemical nature and distribution of low-temperature pyrolysis products from bituminous coal

    Furimsky, E.; Ciavaglia, L.A.; MacPhee, J.A.; Nandi, B.N.; Vancea, L.

    1983-04-01

    Two bituminous coals, a high volatile Eastern Canadian and a medium volatile Western Canadian, were used to investigate the effect of oxidation on yields and chemical composition of gases, liquids and chars produced during coal pyrolysis. Pyrolysis experiments were performed at 500/sup 0/C using the Fischer assay method. Mild oxidation of coals resulted in a decrease of liquid hydrocarbon yields. Further coal oxidation increased the proportion of aromatic carbon in liquid products as determined by n.m.r., and also increased the content of oxygen in liquid products. The content of oxygen in chars was markedly lower than in corresponding coals. An attempt is made to explain reactions occurring during oxidation and subsequent pyrolysis of coal on the basis of differences in chemical composition of gases, liquids and chars.

  16. Taurine and platelet aggregation

    Taurine is a putative neurotransmitter or neuromodulator. The endogenous taurine concentration in human platelets, determined by amino acid analysis, is 15 μM/g. In spite of this high level, taurine is actively accumulated. Uptake is saturable, Na+ and temperature dependent, and suppressed by metabolic inhibitors, structural analogues, and several classes of centrally active substances. High, medium and low affinity transport processes have been characterized, and the platelet may represent a model system for taurine transport in the CNS. When platelets were incubated with 14C-taurine for 30 minutes, then resuspended in fresh medium and reincubated for one hour, essentially all of the taurine was retained within the cells. Taurine, at concentrations ranging from 10-1000 μM, had no effect on platelet aggregation induced by ADP or epinephrine. However, taurine may have a role in platelet aggregation since 35-39% of the taurine taken up by human platelets appears to be secreted during the release reaction induced by low concentrations of either epinephrine or ADP, respectively. This release phenomenon would imply that part of the taurine taken up is stored directly in the dense bodies of the platelet

  17. Holographic characterization of protein aggregates

    Wang, Chen; Zhong, Xiao; Ruffner, David; Stutt, Alexandra; Philips, Laura; Ward, Michael; Grier, David

    Holographic characterization directly measures the size distribution of subvisible protein aggregates in suspension and offers insights into their morphology. Based on holographic video microscopy, this analytical technique records and interprets holograms of individual aggregates in protein solutions as they flow down a microfluidic channel, without requiring labeling or other exceptional sample preparation. The hologram of an individual protein aggregate is analyzed in real time with the Lorenz-Mie theory of light scattering to measure that aggregate's size and optical properties. Detecting, counting and characterizing subvisible aggregates proceeds fast enough for time-resolved studies, and lends itself to tracking trends in protein aggregation arising from changing environmental factors. No other analytical technique provides such a wealth of particle-resolved characterization data in situ. Holographic characterization promises accelerated development of therapeutic protein formulations, improved process control during manufacturing, and streamlined quality assurance during storage and at the point of use. Mrsec and MRI program of the NSF, Spheryx Inc.

  18. Biomimetic Dye Aggregate Solar Cells

    Marek, Peter L.

    2012-01-01

    A biomimetic self-assembling dye, which forms aggregates that mimic the natural light-harvesting system of special photosynthetic active bacteria, has been investigated towards its applicability to solar cells. This fully synthetic dye, self-assembles to orderly structured nano- to micrometer sized rod-shaped aggregates, which might improve solar cells based on conventional organic dyes. In order to use the full potential of the dye aggregates, the self-assembly needed to be controlled and a ...

  19. Aggregation in Large Dynamic Panels

    Pesaran, Mohammad Hashem; Chudik, Alexander

    2011-01-01

    This paper considers the problem of aggregation in the case of large linear dynamic panels, where each micro unit is potentially related to all other micro units, and where micro innovations are allowed to be cross sectionally dependent. Following Pesaran (2003), an optimal aggregate function is derived, and the limiting behavior of the aggregation error is investigated as N (the number of cross section units) increases. Certain distributional features of micro parameters are also identi...

  20. Modifiers of mutant huntingtin aggregation

    Teuling, Eva; Bourgonje, Annika; Veenje, Sven; Thijssen, Karen; Boer, Jelle de; van der Velde, Joeri; Swertz, Morris; Nollen, Ellen

    2011-01-01

    Protein aggregation is a common hallmark of a number of age-related neurodegenerative diseases, including Alzheimer’s, Parkinson’s, and polyglutamine-expansion disorders such as Huntington’s disease, but how aggregation-prone proteins lead to pathology is not known. Using a genome-wide RNAi screen in a C. elegans-model for polyglutamine aggregation, we previously identified 186 genes that suppress aggregation. Using an RNAi screen for human orthologs of these genes, we here present 26 human g...

  1. Aggregation dynamics of rigid polyelectrolytes

    Tom, Anvy Moly; Rajesh, R.; Vemparala, Satyavani

    2016-01-01

    Similarly charged polyelectrolytes are known to attract each other and aggregate into bundles when the charge density of the polymers exceeds a critical value that depends on the valency of the counterions. The dynamics of aggregation of such rigid polyelectrolytes are studied using large scale molecular dynamics simulations. We find that the morphology of the aggregates depends on the value of the charge density of the polymers. For values close to the critical value, the shape of the aggregates is cylindrical with height equal to the length of a single polyelectrolyte chain. However, for larger values of charge, the linear extent of the aggregates increases as more and more polymers aggregate. In both the cases, we show that the number of aggregates decrease with time as power laws with exponents that are not numerically distinguishable from each other and are independent of charge density of the polymers, valency of the counterions, density, and length of the polyelectrolyte chain. We model the aggregation dynamics using the Smoluchowski coagulation equation with kernels determined from the molecular dynamics simulations and justify the numerically obtained value of the exponent. Our results suggest that once counterions condense, effective interactions between polyelectrolyte chains short-ranged and the aggregation of polyelectrolytes are diffusion-limited.

  2. Novel aspects of platelet aggregation

    Roka-Moya Y. M.

    2014-01-01

    Full Text Available The platelet aggregation is an important process, which is critical for the hemostatic plug formation and thrombosis. Recent studies have shown that the platelet aggregation is more complex and dynamic than it was previously thought. There are several mechanisms that can initiate the platelet aggregation and each of them operates under specific conditions in vivo. At the same time, the influence of certain plasma proteins on this process should be considered. This review intends to summarize the recent data concerning the adhesive molecules and their receptors, which provide the platelet aggregation under different conditions.

  3. Platelet aggregation following trauma

    Windeløv, Nis A; Sørensen, Anne M; Perner, Anders;

    2014-01-01

    We aimed to elucidate platelet function in trauma patients, as it is pivotal for hemostasis yet remains scarcely investigated in this population. We conducted a prospective observational study of platelet aggregation capacity in 213 adult trauma patients on admission to an emergency department (ED......). Inclusion criteria were trauma team activation and arterial cannula insertion on arrival. Blood samples were analyzed by multiple electrode aggregometry initiated by thrombin receptor agonist peptide 6 (TRAP) or collagen using a Multiplate device. Blood was sampled median 65 min after injury; median injury...... severity score (ISS) was 17; 14 (7%) patients received 10 or more units of red blood cells in the ED (massive transfusion); 24 (11%) patients died within 28 days of trauma: 17 due to cerebral injuries, four due to exsanguination, and three from other causes. No significant association was found between...

  4. Fractal Aggregation Under Rotation

    WUFeng-Min; WULi-Li; LUHang-Jun; LIQiao-Wen; YEGao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω; thefractal dimension decreases with increasing ω;, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  5. Fractal Aggregation Under Rotation

    WU Feng-Min; WU Li-Li; LU Hang-Jun; LI Qiao-Wen; YE Gao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω the fractal dimension decreases with increasing ω, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  6. Research on Judgment Aggregation Based on Logic

    Li Dai; Jihua Zhang

    2014-01-01

    Preference aggregation and judgment aggregation are two basic research models of group decision making. And preference aggregation has been deeply studied in social choice theory. However, researches of social choice theory gradually focus on judgment aggregation which appears recently. Judgment aggregation focuses on how to aggregate many consistent logical formulas into one, from the perspective of logic. We try to start with judgment aggregation model based on logic and then explore differ...

  7. Computational micromechanical analysis of the representative volume element of bituminous composite materials

    Ozer, Hasan; Ghauch, Ziad G.; Dhasmana, Heena; Al-Qadi, Imad L.

    2016-08-01

    Micromechanical computational modeling is used in this study to determine the smallest domain, or Representative Volume Element (RVE), that can be used to characterize the effective properties of composite materials such as Asphalt Concrete (AC). Computational Finite Element (FE) micromechanical modeling was coupled with digital image analysis of surface scans of AC specimens. Three mixtures with varying Nominal Maximum Aggregate Size (NMAS) of 4.75 mm, 12.5 mm, and 25 mm, were prepared for digital image analysis and computational micromechanical modeling. The effects of window size and phase modulus mismatch on the apparent viscoelastic response of the composite were numerically examined. A good agreement was observed in the RVE size predictions based on micromechanical computational modeling and image analysis. Micromechanical results indicated that a degradation in the matrix stiffness increases the corresponding RVE size. Statistical homogeneity was observed for window sizes equal to two to three times the NMAS. A model was presented for relating the degree of statistical homogeneity associated with each window size for materials with varying inclusion dimensions.

  8. Topics in Probabilistic Judgment Aggregation

    Wang, Guanchun

    2011-01-01

    This dissertation is a compilation of several studies that are united by their relevance to probabilistic judgment aggregation. In the face of complex and uncertain events, panels of judges are frequently consulted to provide probabilistic forecasts, and aggregation of such estimates in groups often yield better results than could have been made…

  9. J-aggregates, v.2

    Kobayashi, Takayoshi

    2012-01-01

    This work deals with J-aggregates, which have a long history of research. The volume covers electronic states, linear and nonlinear optical properties. Various properties and processes of J-aggregates, such as super-radiance, excitons, photon echo, geometrical structure, electron transfer and femtosecond spectroscopy, are discussed.

  10. Molecular aggregation of humic substances

    Wershaw, R. L.

    1999-01-01

    Humic substances (HS) form molecular aggregates in solution and on mineral surfaces. Elucidation of the mechanism of formation of these aggregates is important for an understanding of the interactions of HS in soils arid natural waters. The HS are formed mainly by enzymatic depolymerization and oxidation of plant biopolymers. These reactions transform the aromatic and lipid plant components into amphiphilic molecules, that is, molecules that consist of separate hydrophobic (nonpolar) and hydrophilic (polar) parts. The nonpolar parts of the molecules are composed of relatively unaltered segments of plant polymers and the polar parts of carboxylic acid groups. These amphiphiles form membrane-like aggregates on mineral surfaces and micelle-like aggregates in solution. The exterior surfaces of these aggregates are hydrophilic, and the interiors constitute separate hydrophobic liquid-like phases.

  11. Immunogenicity of Therapeutic Protein Aggregates.

    Moussa, Ehab M; Panchal, Jainik P; Moorthy, Balakrishnan S; Blum, Janice S; Joubert, Marisa K; Narhi, Linda O; Topp, Elizabeth M

    2016-02-01

    Therapeutic proteins have a propensity for aggregation during manufacturing, shipping, and storage. The presence of aggregates in protein drug products can induce adverse immune responses in patients that may affect safety and efficacy, and so it is of concern to both manufacturers and regulatory agencies. In this vein, there is a lack of understanding of the physicochemical determinants of immunological responses and a lack of standardized analytical methods to survey the molecular properties of aggregates associated with immune activation. In this review, we provide an overview of the basic immune mechanisms in the context of interactions with protein aggregates. We then critically examine the literature with emphasis on the underlying immune mechanisms as they relate to aggregate properties. Finally, we highlight the gaps in our current understanding of this issue and offer recommendations for future research. PMID:26869409

  12. DRAG ON SUBMICRON NANOPARTICLE AGGREGATES

    F.; Einar; Kruis

    2005-01-01

    A new procedure was developed for estimating the effective collision diameter of an aggregate composed of primary particles of any size. The coagulation coefficient of two oppositely charged particles was measured experimentally and compared with classic Fuchs theory, including a new method to account for particle non-sphericity. A second set of experiments were performed on well-defined nanoparticle aggregates at different stages of sintering, i.e. from the aggregate to the fully sintered stage. Here, electrical mobility was used to characterize the particle drag. The aggregates are being built from two different size-fractionated nanoparticle aerosols, the non-aggregated particles are discarded by an electrofilter and then they are passed through a furnace at concentrations low enough not to induce coagulation.

  13. Mechanics of fire ant aggregations

    Tennenbaum, Michael; Liu, Zhongyang; Hu, David; Fernandez-Nieves, Alberto

    2016-01-01

    Fire ants link their bodies to form aggregations; these can adopt a variety of structures, they can drip and spread, or withstand applied loads. Here, by using oscillatory rheology, we show that fire ant aggregations are viscoelastic. We find that, at the lowest ant densities probed and in the linear regime, the elastic and viscous moduli are essentially identical over the spanned frequency range, which highlights the absence of a dominant mode of structural relaxation. As ant density increases, the elastic modulus rises, which we interpret by alluding to ant crowding and subsequent jamming. When deformed beyond the linear regime, the aggregation flows, exhibiting shear-thinning behaviour with a stress load that is comparable to the maximum load the aggregation can withstand before individual ants are torn apart. Our findings illustrate the rich, collective mechanical behaviour that can arise in aggregations of active, interacting building blocks.

  14. Erythrocyte aggregation in flowing blood

    This paper addresses the issue of whether nonionic contrast media (CM) promote thrombosis by the formation of large, irregular red blood cell aggregates with videomicroscopy and a flow chamber, red blood cell aggregates adjacent to an endothelial cell monolayer were imaged at 17 sec-1 in dilute suspensions (hematocrit, --8) at 370C in plasma with 20% CM by non-red blood cell volume. All aggregates were rouleaux (<100 μm) readily dispersed at higher shear rates. Aggregate length in eight experiments was increased 11% by ioxaglate (320 mg of iodine per milliliter), decreased 58% by diatrizoate (370 mg of iodine per milliliter) but reduced similarly (16%) by iohexol (350 mg of iodine per milliliter) and saline. Iohexol did not enhance platelet aggregation on injured monolayers

  15. RankAggreg, an R package for weighted rank aggregation

    Datta Susmita

    2009-02-01

    Full Text Available Abstract Background Researchers in the field of bioinformatics often face a challenge of combining several ordered lists in a proper and efficient manner. Rank aggregation techniques offer a general and flexible framework that allows one to objectively perform the necessary aggregation. With the rapid growth of high-throughput genomic and proteomic studies, the potential utility of rank aggregation in the context of meta-analysis becomes even more apparent. One of the major strengths of rank-based aggregation is the ability to combine lists coming from different sources and platforms, for example different microarray chips, which may or may not be directly comparable otherwise. Results The RankAggreg package provides two methods for combining the ordered lists: the Cross-Entropy method and the Genetic Algorithm. Two examples of rank aggregation using the package are given in the manuscript: one in the context of clustering based on gene expression, and the other one in the context of meta-analysis of prostate cancer microarray experiments. Conclusion The two examples described in the manuscript clearly show the utility of the RankAggreg package in the current bioinformatics context where ordered lists are routinely produced as a result of modern high-throughput technologies.

  16. Perspectives on Preference Aggregation.

    Regenwetter, Michel

    2009-07-01

    For centuries, the mathematical aggregation of preferences by groups, organizations, or society itself has received keen interdisciplinary attention. Extensive theoretical work in economics and political science throughout the second half of the 20th century has highlighted the idea that competing notions of rational social choice intrinsically contradict each other. This has led some researchers to consider coherent democratic decision making to be a mathematical impossibility. Recent empirical work in psychology qualifies that view. This nontechnical review sketches a quantitative research paradigm for the behavioral investigation of mathematical social choice rules on real ballots, experimental choices, or attitudinal survey data. The article poses a series of open questions. Some classical work sometimes makes assumptions about voter preferences that are descriptively invalid. Do such technical assumptions lead the theory astray? How can empirical work inform the formulation of meaningful theoretical primitives? Classical "impossibility results" leverage the fact that certain desirable mathematical properties logically cannot hold in all conceivable electorates. Do these properties nonetheless hold true in empirical distributions of preferences? Will future behavioral analyses continue to contradict the expectations of established theory? Under what conditions do competing consensus methods yield identical outcomes and why do they do so? PMID:26158988

  17. Bituminous solidification, disposal, transport and burial of spent ion-exchange resins. Part of a coordinated programme on treatment of spent ion exchange resins

    The project dealing with the incorporation of spent ion-exchange resins into bitumen was performed within the Agency coordinated research programme on treatment of spent ion-exchange resins. Physical and chemical properties of commercial ion-exchange resins, bitumens and bituminized resins were studied. It was shown that bitumen with low oil content and with a softening point of 60-70 deg. C are applicable for the incorporation of resins. The final waste form is allowed to contain maximum 50% resin. The comprehensive study of the biological resistance of B-30 bitumen was performed. That showed that any bacteriological attack can be regarded as generally insignificant. A continuously operating technology was realized on a semi-plant scale. The best operating conditions of this technology were determined. On the basis of the experience gained from the experiments a design of the bituminization plant of 50m3 dry resin/year treatment capacity was proposed

  18. Advances in Interlaboratory Testing and Evaluation of Bituminous Materials State-of-the-Art Report of the RILEM Technical Committee 206-ATB

    Bahia, Hussain; Canestrari, Francesco; Roche, Chantal; Benedetto, Hervé; Piber, Herald; Sybilski, Dariusz

    2013-01-01

    This STAR on asphalt materials presents the achievements of RILEM TC 206 ATB, acquired over many years of interlaboratory tests and international knowledge exchange. It covers experimental aspects of bituminous binder fatigue testing; the background on compaction methods and imaging techniques for characterizing asphalt mixtures including validation of a new imaging software; it focuses on experimental questions and analysis tools regarding mechanical wheel tracking tests, comparing results from different labs and using finite element techniques. Furthermore, long-term rutting prediction and evaluation for an Austrian road are discussed, followed by an extensive analysis and test program on interlayer bond testing of three different test sections which were specifically constructed for this purpose. Finally, the key issue of manufacturing reclaimed hot mix asphalt in the laboratory is studied and recommendations for laboratory ageing of bituminous mixtures are given.

  19. Dust is the dominant source of "heavy metals" to peat moss (Sphagnum fuscum) in the bogs of the Athabasca Bituminous Sands region of northern Alberta.

    Shotyk, William; Bicalho, Beatriz; Cuss, Chad W; Duke, M John M; Noernberg, Tommy; Pelletier, Rick; Steinnes, Eiliv; Zaccone, Claudio

    2016-01-01

    Sphagnum fuscum was collected from twenty-five ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca Bituminous Sands (ABS) in northern Alberta (AB) in order to assess the extent of atmospheric contamination by trace elements. As a control, this moss species was also collected at a bog near Utikuma (UTK) in an undeveloped part of AB and 264km SW of the ABS region. For comparison, this moss was also collected in central AB, in the vicinity of the City of Edmonton which is approximately 500km to the south of the ABS region, from the Wagner Wetland which is 22km W of the City, from Seba Beach (ca. 90km W) and from Elk Island National Park (ca. 45km E). All of the moss samples were digested and trace elements concentrations determined using ICP-SMS at a commercial laboratory, with selected samples also analyzed using instrumental neutron activation analysis at the University of Alberta. The mosses from the ABS region yielded lower concentrations of Ag, As, Bi, Cd, Cu, Pb, Sb, Tl, and Zn compared to the moss from the Edmonton area. Concentrations of Ni and Mo in the mosses were comparable in these two regions, but V was more abundant in the ABS samples. Compared with the surface vegetation of eight peat cores collected in recent years from British Columbia, Ontario, Quebec and New Brunswick, the mean concentrations of Ag, As, Bi, Cd, Cu, Mo, Ni, Pb, Sb, Tl and Zn in the mosses from the ABS region are generally much lower. In fact, the concentrations of these trace elements in the samples from the ABS region are comparable to the corresponding values in forest moss from remote regions of central and northern Norway. Lithophile element concentrations (Ba, Be, Ga, Ge, Li, Sc, Th, Ti, Zr) explain most of the variation in trace metal concentrations in the moss samples. The mean concentrations of Th and Zr are greatest in the moss samples from the ABS region, reflecting dust inputs to the bogs from open pit mines, aggregate

  20. Effect of transesterification degree and post-treatment on the in-service performance of NCO-functionalized vegetable oil bituminous products

    Cuadri Vega, Antonio Abad; García Morales, Moisés; Navarro Domínguez, Francisco Javier; Partal López, Pedro

    2014-01-01

    The bitumen modification through polyurethane prepolymers presents significant benefits for the manufacture of bituminous products for the paving industry. In this sense, this work explores the use, as bitumen modifier, of a novel reactive prepolymer synthesized by reaction of 4,4´,diphenylmethane diisocyanate (MDI) and a vegetable oil-based polyol, castor oil (CO), previously transesterified with pentaerythritol. On the one hand, thermal analysis on transesterified CO revealed a highly stabl...

  1. Evaluation of bituminized waste reactivity; Maitrise de la reactivite thermique lors de l'elaboration d'un conditionnement de dechets radioactifs par le bitume

    Camaro, S.; Moulinier, D. [CEA Saclay, Dept. d' Entreposage et de Stockage des Dechets (DCC/DESD/SEP), 91 - Gif-sur-Yvette (France)

    2000-07-01

    The bituminization process has been used for conditioning low and medium level (LML) radioactive waste, particularly to immobilize coprecipitation slurries and evaporation concentrates generated by effluent treatment. The process consists in mixing bitumen matrix with inactive soluble and slightly soluble salts added to insolubilize the radionuclides or resulting from the neutralization of acid effluents. This operation is performed at a sufficient temperature - depending on waste composition and bitumen grade to ensure the flow of the resulting mixture into metal containers. Exothermicity due to salts/salts or salts/bitumen reactions depending on the type of waste can be induced during or after the mixing step. This could produce an additional heat emission that the drum must be able to release to avoid a potentially incidental pattern with ignition risk, explaining why the CEA has been involved in evaluating the thermal reactivity of bituminized waste and its repercussions on the bituminization process. Given the difficulty of discriminating each exothermal reaction, the characterization of a global reactivity appears as a further precautionary measure, in addition to the definition of a working safety margin. The CEA has accordingly developed studies on this aspect. The article discusses the experimental methodology developed for the determination of the global reactivity. (authors)

  2. Anonymous aggregator election and data aggregation in wireless sensor networks

    Tamás Holczer; Levente Buttyán

    2011-01-01

    In mission critical cyber-physical systems, dependability is an important requirement at all layers of the system architecture. In this paper, we propose protocols that increase the dependability of wireless sensor networks, which are potentially useful building blocks in cyber-physical systems. More specifically, we propose two private aggregator node election protocols, a private data aggregation protocol, and a corresponding private query protocol for sensor networks that allow for secure ...

  3. Co-combustion of bituminous coal and biomass fuel blends: Thermochemical characterization, potential utilization and environmental advantage.

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui

    2016-10-01

    The thermochemical characteristics and gaseous trace pollutant behaviors during co-combustion medium-to-low ash bituminous coal with typical biomass residues (corn stalk and sawdust) were investigated. Lowering of ignition index, burnout temperature and activation energy in the major combustion stage are observed in the coal/biomass blends. The blending proportion of 20% and 30% are regarded as the optimum blends for corn stalk and sawdust, respectively, in according the limitations of heating value, activation energy, flame stability and base/acid ratio. The reductions of gaseous As, Cd, Cu, Pb, Zn and polycyclic aromatic hydrocarbon (PAHs) were 4.5%, 7.8%, 6.3%, 9.8%, 9.4% and 17.4%, respectively, when co-combustion coal with 20% corn stalk. The elevated capture of trace elements were found in coal/corn stalk blend, while the coal/sawdust blend has the better PAHs control potential. The reduction mechanisms of gaseous trace pollutants were attributed to the fuel property, ash composition and relative residence time during combustion. PMID:27393832

  4. Utilising neural networks and closed form solutions to determine static creep behaviour and optimal polypropylene amount in bituminous mixtures

    Serkan Tapkın

    2012-12-01

    Full Text Available The testing procedure in order to determine the precise mechanical testing results in Marshall design is very time consuming. Also, the physical properties of the asphalt samples are obtained by further calculations. Therefore if the researchers can obtain the stability and flow values of a standard mixture with the help of mechanical testing, the rest of the calculations will just be mathematical manipulations. Determination of mechanical testing parameters such as strain accumulation, creep stiffness, stability, flow and Marshall Quotient of dense bituminous mixtures by utilising artificial neural networks is important in the sense that, cumbersome testing procedures can be avoided with the help of the closed form solutions provided in this study. Marshall specimens, prepared by utilising polypropylene fibers, were tested by universal testing machine carrying out static creep tests to investigate the rutting potential of these mixtures. On the very well trained data basis, artificial neural network analyses were carried out to propose five separate models for mechanical testing properties. The explicit formulation of these five main mechanical testing properties by closed form solutions are presented for further use for researches.

  5. Dye-adsorption capacity of bituminous fly ash and its pozzolanic property after used as dye-adsorbent

    Penpolcharoen, M.

    2004-02-01

    Full Text Available Bituminous fly ash, which is an industrial waste, was used as an adsorbent to remove dyestuff from the textile-dye wastewater. The batch kinetic and isotherm experiments of the synthetic wastewater were firstly conducted to determine the adsorption behavior and optimal conditions for adsorption. The optimal conditions were then applied to the actual textile-dye wastewater. Under the original conditions of fly ash and wastewater, the results indicated that the color could be removed up to 86.65% by 12 g of the fly ash /L of the wastewater within 30 min. Its adsorption was described by the Freundlich isotherm. The dye-adsorbed fly ash was further studied on its pozzolanic property in terms of compressive strength by using it as a partial substitute to Portland cement type I to produce mortar. The result revealed that the highest compressive strength was of the sample containing 10% by weight of the dye-adsorbed fly ash in replacement of cement. It possessed 215 kg/cm2 at 28 days, which is 92.67% of the sample containing 10% by weight of the original fly ash in replacement of cement, or 83.33 of the cement mortar. For the environmental concern, leachabilities of lead (Pb, chromium (Cr, copper (Cu and zinc (Zn from all mortars were also carried out. No leaching of the heavy metals from any samples could be detected. Hence, the dye-adsorbed fly ash can be used as an environmental friendly construction material.

  6. Nuclear method for determination of asphalt content corrected for moisture in bituminous mixture. Final report, March 1988-February 1989

    This report presents results of research on the development of a method for determination of asphalt content corrected for moisture using the nuclear-gauge method. The researchers selected an approach that involved rapid drying of the asphalt concrete samples in a microwave oven prior to the determination of asphalt content using a Troxler Model 3241-C nuclear asphalt-content gauge. As a reference, asphalt contents were also measured using quantitative extraction. In general, good agreement was found between asphalt contents measured by the Troxler Model 3241-C nuclear gauge and asphalt contents measured by quantitative extraction. In extended sampling for Plant 1, no significant increase in nuclear gauge error was seen over a 10-day sampling period, which indicates that daily calibration of the nuclear gauge is probably unnecessary to maintain satisfactory performance. The field demonstration of the procedure of drying the bituminous mixture in a microwave oven and then determining its asphalt content by the nuclear method indicated asphalt-content results were obtained approximately 1 hour faster than results obtained by quantitative extraction

  7. JV Task-123 Determination of Trace Element Concentrations at an Eastern Bituminous Coal Plant Employing an SCR and Wet FGD

    Dennis Laudal

    2008-05-01

    The Energy & Environmental Research Center (EERC), in partnership with Babcock & Wilcox (B&W) and with funding from U.S. Department of Energy (DOE), conducting tests to prove that a high level of mercury control (>90%) can be achieved at a power plant burning a high-sulfur eastern bituminous coal. With funding from the Electric Power Research Institute (EPRI), DOE, and Center for Air Toxic Metals{reg_sign} (CATM{reg_sign}) Affiliates Program, the EERC completed an additional sampling project to provide data as to the behavior of a number of trace elements across the various pollution control devices, with a special emphasis on the wet flue gas desulfurization (FGD) system. Results showed that the concentrations of almost all the elements of interest leaving the stack were very low, and a high percentage of the trace elements were captured in the electrostatic precipitator (ESP) (for most, >80%). Although, with a few exceptions, the overall mass balances were generally quite good, the mass balances across the wet FGD were more variable. This is most likely a result of some of the concentrations being very low and also the uncertainties in determining flows within a wet FGD.

  8. Applied Technological Direction of Power Plant Ash and Slag Waste Management when Kuznetsk Bituminous Coal is Burned

    Lihach Snejana A.

    2016-01-01

    Full Text Available Currently a lot of power plants have a problem with storage of coal combustion solid by-products (ash and slag. Holding capacity of existing power plants available ash dumps were enlarged and modernized repeatedly. Many plants have two or even three of them. Today new ash dump construction is economically inconvenient due to need to assign new plots of land and their inconveniently big distance from a plant, which increase ash and slag transportation expenses. The goal of our research work is to find promising directions for ash and slag waste mass utilization based on Kuznetsk bituminous coals experimental data on ultimate composition and properties. The experimental research of ash, slag and their mixture samples from ash dumps brought us to conclusion that the most promising direction for these materials application in large quantities is construction industry including road construction. Be-sides, we lined up some other directions for ash, slag, and ash and slag mixture possible application. These directions might not provide mass utilization but they are promising from a point of view of the researched waste properties.

  9. Arrow’s theorem in judgment aggregation

    Dietrich, Franz; List, Christian

    2005-01-01

    In response to recent work on the aggregation of individual judgments on logically connected propositions into collective judgments, it is often asked whether judgment aggregation is a special case of Arrowian preference aggregation. We argue for the converse claim. After proving two impossibility theorems on judgment aggregation (using “systematicity” and “independence” conditions, respectively), we construct an embedding of preference aggregation into judgment aggregation and prove Arrow’s ...

  10. Aggregated Computational Toxicology Resource (ACTOR)

    U.S. Environmental Protection Agency — The Aggregated Computational Toxicology Resource (ACTOR) is a database on environmental chemicals that is searchable by chemical name and other identifiers, and by...

  11. Isolation and Aggregation in Economics

    Schlicht, Ekkehart

    1985-01-01

    In explaining economic phenomena, economic analysis concentrates on selected influences and fixes the host of other factors under a ceteris paribus clause. This view, which goes back to Alfred Marshall (1842-1924), is developed in the first part of the book. Aggregation is viewed as a particular application of ceteris paribus analysis - isolation from "structural effects". This leads to an approach, called "closed aggregation", which was introduced by Kenneth May and is also implicit in Keyne...

  12. Judgment aggregation with consistency alone

    Dietrich, Franz; List, Christian

    2007-01-01

    All existing impossibility theorems on judgment aggregation require individ- ual and collective judgment sets to be consistent and complete (in some recent results with completeness relaxed to deductive closure), arguably a demand- ing rationality requirement. They do not carry over to aggregation functions mapping pro…les of (merely) consistent individual judgment sets to (merely) consistent collective ones. We prove that, whenever the agenda of propositions under consideration exhibits mild...

  13. Judgment aggregation without full rationality

    Dietrich, Franz; List, Christian

    2007-01-01

    Several recent results on the aggregation of judgments over logically connected propositions show that, under certain conditions, dictatorships are the only independent (i.e., propositionwise) aggregation rules generating fully rational (i.e., complete and consistent) collective judgments. A frequently mentioned route to avoid dictatorships is to allow incomplete collective judgments. We show that this route does not lead very far: we obtain (strong) oligarchies rather than dictatorships if i...

  14. Familial aggregation of cluster headache

    Cruz, S; Lemos, C; Monteiro, JM

    2013-01-01

    Several studies suggest a strong familial aggregation for cluster headache (CH), but so far none of them have included subjects with probable cluster headache (PCH) in accordance with the International Classification of Headache Disorders. OBJECTIVE: To identify cases of probable cluster headache and to assess the familial aggregation of cluster headache by including these subjects. METHOD: Thirty-six patients attending a headache consultation and diagnosed with trigeminal autonom...

  15. Familial aggregation of cluster headache

    Simao Cruz; Carolina Lemos; Jose Maria Pereira Monteiro

    2013-01-01

    Several studies suggest a strong familial aggregation for cluster headache (CH), but so far none of them have included subjects with probable cluster headache (PCH) in accordance with the International Classification of Headache Disorders. Objective To identify cases of probable cluster headache and to assess the familial aggregation of cluster headache by including these subjects. Method Thirty-six patients attending a headache consultation and diagnosed with trigeminal autonomic headache...

  16. Glycation precedes lens crystallin aggregation

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [3H]NaBH4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

  17. Kinetic model for erythrocyte aggregation.

    Bertoluzzo, S M; Bollini, A; Rasia, M; Raynal, A

    1999-01-01

    It is well known that light transmission through blood is the most widely utilized method for the study of erythrocyte aggregation. The curves obtained had been considered empirically as exponential functions. In consequence, the process becomes characterized by an only parameter that varies with all the process factors without discrimination. In the present paper a mathematical model for RBC aggregation process is deduced in accordance with von Smoluchowski's theory about the kinetics of colloidal particles agglomeration. The equation fitted the experimental pattern of the RBC suspension optical transmittance closely and contained two parameters that estimate the most important characteristics of the aggregation process separately, i.e., (1) average size of rouleaux at equilibrium and (2) aggregation rate. The evaluation of the method was assessed by some factors affecting erythrocyte aggregation, such as temperature, plasma dilutions, Dextran 500, Dextran 70 and PVP 360, at different media concentrations, cellular membrane alteration by the alkylating agent TCEA, and decrease of medium osmolarity. Results were interpreted considering the process characteristics estimated by the parameters, and there were also compared with similar studies carried out by other authors with other methods. This analysis allowed us to conclude that the equation proposed is reliable and useful to study erythrocyte aggregation. PMID:10660481

  18. QUERY PLANNING FOR CONTINUOUS AGGREGATION QUERIES USING DATA AGGREGATORS

    A. SATEESH, D. ANIL, M. KIRANKUMAR

    2013-08-01

    Full Text Available Continuous aggregation queries are used to monitor the changes in data with time varying for online decision making. For continuous queries low cost and scalable techniques used a network of aggregators. Individual node cannot by itself determine its inclusion in the query result for this a different algorithmic challenges from aggregate and selection queries are presented. At specific coherencies each data item can serve for a set of data aggregators. Technique involves disseminating query into sub query and sub queries are executed on the chosen data aggregators. We build a query cost model which can be used to estimate the number of refresh messages which is required to satisfy the client specified incoherency bound. Performance results shows that by our method the query can be executed using less than one third the messages required for existing schemes. Our adaptive strategy employs distributed decisions made by the distributed servers independently based on localized statistics collected by each server at runtime. When comparatively static environment, propose two motionless tree construction algorithms relying on apriori system statistics. These static trees can also be used as early trees in a dynamic environment and apply our schemes to both single- and multi object distribution. Our extensive performance study illustrate that the adaptive mechanisms.

  19. Effect of asphaltene and resin oils on the viscosity of bituminous petroleum materials to be used as asphalt primers

    Bencomo, M. R.

    2006-03-01

    Full Text Available The bituminous crude from the Machete, Venezuela, area, which has such a fluid consistency that it falls outside the normal scope of the A5TM D-5 (1 penetration test exceeding the 3D-mm ceiling specified in that standard and can be used as an asphalt primer: Like other asphalt products, these materials are -chemically speaking- a mix of numerous naphthenic, paraffinic and aromatic hydrocarbons and heterocyclic compounds containing sulphur, nitrogen, oxygen and so on. They have a dense and a malthene oil phase which, along with the natural hydrocarbons additives used in these products acts as a volatile fluidizer. The former is described as a mix of asphaltenes: complex high molecular weight substances that are insoluble in paraffinic hydrocarbons and soluble in aromatic compounds such as benzene. The malthene oil phase, in turn, consists in a mix of resins and hydrocarbons and together the two constitute a colloidal system. The experiments discussed in the present paper were conducted to determine the effect of the proportion of asphaltenes and resin oils on the viscosity of such bituminous crude emulsions/ with a view to their use as primers. These experiments were run in a Parr batch reactor in a nitrogen atmosphere using n-heptane as a solvent. The resins were separated after the asphaltenes precipitated from the samples and subsequently from the malthene fraction obtained. The results showed that the asphaltenes account for the structural characteristics and consistency of the medium and the resin oils for its cohesive properties/,the malthene oils act as solvents.Los crudos extrapesados procedentes del área Machete (Venezuela son materiales de consistencia blanda o fluida, por lo que se salen del campo en el que normalmente se aplica el ensayo de penetración a productos asfálticos según el método ASTM D-5 (1, cuyo límite máximo es 30 mm, y pueden ser utilizados como pinturas asfálticas de imprimación. Al igual que otros productos

  20. Fractal Aggregates in Tennis Ball Systems

    Sabin, J.; Bandin, M.; Prieto, G.; Sarmiento, F.

    2009-01-01

    We present a new practical exercise to explain the mechanisms of aggregation of some colloids which are otherwise not easy to understand. We have used tennis balls to simulate, in a visual way, the aggregation of colloids under reaction-limited colloid aggregation (RLCA) and diffusion-limited colloid aggregation (DLCA) regimes. We have used the…

  1. Functional group and individual maceral chemistry of high volatile bituminous coals from southern Indiana: Controls on coking

    Walker, R.; Mastalerz, Maria

    2004-01-01

    The individual maceral chemistries of two Pennsylvanian, high volatile bituminous coals, the Danville Coal Member (Dugger Formation, R o=0.55%) and the Lower Block Coal Member (Brazil Formation, R o=0.56%) of Indiana, were investigated using electron microprobe and Fourier Transform Infrared Spectrometry (FTIR) techniques, with the purpose of understanding differences in their coking behavior. Microprobe results reveal that carbon contents are highest in inertinite and sporinite, followed by desmocollinite and telocollinite. Oxygen and organic nitrogen are most abundant in telocollinite and desmocollinite; sporinite and inertinite contain lesser amounts of these two elements. Organic sulfur contents are highest in sporinite, lowest in inertinite, and intermediate in desmocollinite and telocollinite. Vitrinites within the Danville and Lower Block coals are very similar in elemental composition, while Lower Block inertinites and sporinites have higher carbon, lower oxygen, and sulfur contents which, when combined with the inertinite-and sporinite-rich composition of the Lower Block seam, strongly influences its whole coal chemistry. Fourier transform infrared spectrometry revealed greater aromatic hydrogen in the Lower Block coal, along with higher CH2/CH3 ratios, which suggest that liptinites contribute considerable amounts of long-chain, unbranched aliphatics to the overall kerogen composition of the Lower Block coal. Long-chain, unbranched aliphatics crack at higher temperatures, producing tar and oily byproducts during coking; these may help increase Lower Block plasticity. Electron microprobe and FTIR results indicate that individual maceral chemistries, combined with the maceral composition of the seam, are the primary control of better coking properties of the Lower Block coal. ?? 2003 Elsevier B.V. All rights reserved.

  2. Processes related to the water uptake by EUROBITUM bituminized radioactive waste: Theoretical considerations and first experimental results

    According to the present Belgian radioactive waste management program, EUROBITUM bituminized radioactive waste will be disposed of in a geologically stable underground clay formation. The Boom Clay is studied as a potential host formation because of its low diffusion and high retention properties towards radionuclides. The presence of the radioactive waste should not disturb these properties. Due to the presence of hygroscopic salts (25 to 30 weight% NaNO3), EUROBITUM will take up pore water which will result in a swelling and possibly in a very high swelling pressure. First scoping calculations suggest that the swelling pressure exerted to Boom Clay should remain below 7 to 8 MPa to avoid the formation of fractures. If the bitumen in EUROBITUM behaved like a perfect semi-permeable membrane and if no swelling were allowed after the dissolution of NaNO3 into a saturated solution of 10.8 M, osmotic pressures of ∼50 MPa could be attained. To better understand the interaction between the swelling EUROBITUM and the host formation, coupled hydro-chemical-mechanical constitutive laws for EUROBITUM have to be developed. To this purpose, water uptake tests under constant volume ('confined') and constant stress ('semi-confined') conditions are being performed. After ∼2 years of hydration of small inactive EUROBITUM samples in constant volume conditions, the swelling pressure has raised to ∼12 MPa. The volume of samples that can swell against counter pressures of 2.2, 3.3, or 4.4 MPa (constant stress tests) increased with ∼5 to 11 volume%, independently of the applied counter pressure. Approximately 10 weight% of the initial NaNO3 content has been leached. (authors)

  3. Radioactivity concentrations and dose assessment for bitumen and soil samples around a bituminous deposit in Ondo State, Nigeria

    Bitumen samples and soil samples around a bituminous deposit in Ondo State, Nigeria, were analysed for 40K, 226Ra and 232Th employing gamma-ray spectrometry. The activity concentrations of 40K, 226Ra and 232Th in soil varied from (45.2 ± 5.3) to (484.2 ± 25.9), BDL (below detectable limit) to (27.7 ± 2.1) and (22.8 ± 2.7) to (62.4 ± 6.8) Bq.kg-1, respectively. The corresponding mean values were (240.2 ± 133.5), (13.3 ± 8.0) and (40.0 ± 10.2) Bq.kg-1, respectively. The mean activity concentrations of the radionuclides in the bitumen were (58.4 ± 36.4), (16.1 ± 13.3) and (32.5 ± 13.1) Bq.kg-1, respectively, for 40K, 226Ra and 232Th. The mean absorbed dose and effective dose for the soil samples were (41.5 ± 8.9) nGy.h-1 and (50.7 ± 10.9) μSv.y-1, respectively, while those of the bitumen samples were (29.5 ± 15.6) nGy.h-1 and (36.1 ± 19.1) μSv.y-1, respectively. For radiological hazard assessment, the radium equivalent activity and the external hazard index were determined. The values of the radium equivalent activity and external hazard index obtained for the soil and bitumen samples were lower than the recommended limit. (authors)

  4. An exact approach for aggregated formulations

    Gamst, Mette; Spoorendonk, Simon; Røpke, Stefan

    Aggregating formulations is a powerful approach for problems to take on tractable forms. Aggregation may lead to loss of information, i.e. the aggregated formulation may be an approximation of the original problem. In branch-and-bound context, aggregation can also complicate branching, e.g. when...... optimality cannot be guaranteed by branching on aggregated variables. We present a generic exact solution method to remedy the drawbacks of aggregation. It combines the original and aggregated formulations and applies Benders' decomposition. We apply the method to the Split Delivery Vehicle Routing Problem....

  5. Destructive Strength Properties of Recycled Coarse Aggregate

    Chetna M Vyas,; Darshana R Bhatt,

    2013-01-01

    Due to a critical shortage of natural aggregate, the availability of demolished concrete for use as recycled coarse aggregate (RCA) is increasing. Use of waste concrete as RCA conserves natural aggregate, reduces the impact on landfills, save energy and can provide cost benefit. Recycled aggregates are the materials for the future. The application of recycled aggregate has been started in many Asian & Western countries for construction projects. Research Paper reports the basic strength prope...

  6. Erythrocyte aggregation: Basic aspects and clinical importance

    Başkurt, Oğuz K.; Meiselman, Herbert J.

    2013-01-01

    Red blood cells (RBC) aggregate to form two- and three-dimensional structures when suspended in aqueous solutions containing large plasma proteins or polymers; this aggregation is reversible and shear dependent (i.e., dispersed at high shear and reformed at low or stasis). The extent of aggregation is the main determinant of low shear blood viscosity, thus predicting an inverse relationship between aggregation and in vivo blood flow. However, the effects of aggregation on hemodynamic mechanis...

  7. Individual income, incomplete information, and aggregate consumption

    Pischke, J.

    1991-01-01

    In this paper I study a model of life-cycle consumption in which individuals react optimally to their own income process but ignore economy wide information. Since individual income is less persistent than aggregate income consumers will react too little to aggregate income variation. Aggregate consumption will be excessively smooth. Since aggregate information is slowly incorporated into consumption, aggregate consumption will be autocorrelated and correlated with lagged income. The second p...

  8. Turbulent breakage of ductile aggregates

    Marchioli, Cristian

    2015-01-01

    In this paper we study breakage rate statistics of small colloidal aggregates in non-homogeneous anisotropic turbulence. We use pseudo-spectral direct numerical simulation of turbulent channel flow and Lagrangian tracking to follow the motion of the aggregates, modelled as sub-Kolmogorov massless particles. We focus specifically on the effects produced by ductile rupture: This rupture is initially activated when fluctuating hydrodynamic stresses exceed a critical value, $\\sigma>\\sigma_{cr}$, and is brought to completion when the energy absorbed by the aggregate meets the critical breakage value. We show that ductile rupture breakage rates are significantly reduced with respect to the case of instantaneous brittle rupture (i.e. breakage occurs as soon as $\\sigma>\\sigma_{cr}$). These discrepancies are due to the different energy values at play as well as to the statistical features of energy distribution in the anisotropic turbulence case examined.

  9. Equilibrium structure of ferrofluid aggregates

    We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a competition between various energy terms, which can be approximated analytically within a continuum model. We also study the effect of external parameters such as magnetic field on the relative stability of these structures. Our results may give insight into experimental data obtained during solidification of ferrofluid aggregates at temperatures where thermal fluctuations become negligible in comparison to inter-particle interactions. These data may also help to experimentally control the aggregation of magnetic particles.

  10. Molecular Aggregation in Disodium Cromoglycate

    Singh, Gautam; Agra-Kooijman, D.; Collings, P. J.; Kumar, Satyendra

    2012-02-01

    Details of molecular aggregation in the mesophases of the anti-asthmatic drug disodium cromoglycate (DSCG) have been studied using x-ray synchrotron scattering. The results show two reflections, one at wide angles corresponding to π-π stacking (3.32 å) of molecules, and the other at small angles which is perpendicular to the direction of molecular stacking and corresponds to the distance between the molecular aggregates. The latter varies from 35 - 41 å in the nematic (N) phase and 27 -- 32 å in the columnar (M) phase. The temperature evolution of the stack height, positional order correlations in the lateral direction, and orientation order parameter were determined in the N, M, and biphasic regions. The structure of the N and M phases and the nature of the molecular aggregation, together with their dependence on temperature and concentration, will be presented.

  11. Photostimulated Aggregation of Metal Aerosols

    Karpov, Sergei V

    2010-01-01

    The effect of optical radiation on the rate of aggregation of nanoscopic particles is studied in metal aerosols. It has been shown that under light exposure, polydisperse metal aerosols can aggregate up to two orders faster due to the size dependent photoelectron effect from nanoparticles. Different size nanoparticles undergo mutual heteropolar charging when exchanging photoelectrons through the interparticle medium to result in an increased rate of aggregation. It is shown that long-range electrostatic attractive forces drive the particles into closer distances where the short-range Van-der-Waals forces become dominating. Attention is drawn to the fact that this effect may occur in various types of dispersed systems as well as in natural heteroaerosols.

  12. Quantum Diffusion-Limited Aggregation

    Johnson, David B

    2011-01-01

    Though classical random walks have been studied for many years, research concerning their quantum analogues, quantum random walks, has only come about recently. Numerous simulations of both types of walks have been run and analyzed, and are generally well-understood. Research pertaining to one of the more important properties of classical random walks, namely, their ability to build fractal structures in diffusion-limited aggregation, has been particularly noteworthy. However, only now has research begun in this area in regards to quantum random motion. The study of random walks and the structures they build has various applications in materials science. Since all processes are quantum in nature, it is important to consider the quantum variant of diffusion-limited aggregation. Recognizing that Schr\\"odinger equation and a classical random walk are both diffusion equations, it is possible to connect and compare them. Using similar parameters for both equations, we ran various simulations aggregating particles....

  13. Balancing energy flexibilities through aggregation

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2014-01-01

    in both energy production and consumption, is the key to solving these problems. Flexibilities can be expressed as flex-offers, which due to their high number need to be aggregated to reduce the complexity of energy scheduling. In this paper, we discuss balance aggregation techniques that already......One of the main goals of recent developments in the Smart Grid area is to increase the use of renewable energy sources. These sources are characterized by energy fluctuations that might lead to energy imbalances and congestions in the electricity grid. Exploiting inherent flexibilities, which exist...... during aggregation aim at balancing flexibilities in production and consumption to reduce the probability of congestions and reduce the complexity of scheduling. We present results of our extensive experiments....

  14. Detection of rare earth elements in Powder River Basin sub-bituminous coal ash using laser-induced breakdown spectroscopy (LIBS)

    Tran, Phuoc [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State; Mcintyre, Dustin [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State

    2015-10-01

    We reported our preliminary results on the use of laser-induced breakdown spectroscopy to analyze the rare earth elements contained in ash samples from Powder River Basin sub-bituminous coal (PRB-coal). We have identified many elements in the lanthanide series (cerium, europium, holmium, lanthanum, lutetium, praseodymium, promethium, samarium, terbium, ytterbium) and some elements in the actinide series (actinium, thorium, uranium, plutonium, berkelium, californium) in the ash samples. In addition, various metals were also seen to present in the ash samples

  15. Disposal of bituminized and other low- and medium-level wastes: Waste characterization and the retention of migrating radionuclides by steel corrosion products

    Biegalski, Kendra Mylene Foltz

    1998-09-01

    The validity of using scaling factors with the reference nuclide, sp{137}Cs, for activity determinations of sp{238}Pu, sp{239,\\ 240}Pu, and sp{241}Am in low- and medium-level bituminized and unconditioned evaporator concentrates (ECs) produced at Riso National Laboratory (RNL), Denmark was investigated. The presence of constant activity ratios between sp{137}Cs and the Pu isotopes above was predicted because a large part of this waste stream originated from research on irradiated light water reactor fuel. Activity ratios were measured in different waste samples by comparison of gamma-measurements to results from destructive analyses using alpha-spectrometry. Results were verified using activity ratios of spent low-enriched fuel from the literature. Continuation studies on the mechanisms influencing releases from bituminized low- and medium-level wastes were performed by leach tests on samples of various compositions and exposed to diverse environments. Four compositions of bituminized materials were studied including (1) bitumen with NaNOsb3 and BaSOsb4, (2) bitumen with NaNOsb3, BaSOsb4, and Nisb2Fe(CN)sb6, (3) bitumen with NaNOsb3, BaSOsb4, Nisb2Fe(CN)sb6, and K-soap, and (4) bituminized RNL ECs. Leachant solutions used included (1) filtered deionized water, (2) 0.001-N KOH, (3) 0.01-N KOH, and (4) 0.001-N Ca(OH)sb2. One trial was exposed to high-humidity air while two others had a cement disk suspended in the leachant. Some of the resulting data was used for the on-going validation of the SWL (Swelling, Water uptake, and Leaching) code created at RNL. To improve the accuracy of projected releases from radioactive waste disposal systems, the sorption characteristics of steel corrosion products were investigated with a special emphasis on competitive sorption between Sr and Na. The corrosion rate of steel exposed to various environments was studied qualitatively and, with some systems, quantitatively. Traditional and non-traditional adsorption

  16. Studies on recycled aggregates-based concrete.

    Rakshvir, Major; Barai, Sudhirkumar V

    2006-06-01

    Reduced extraction of raw materials, reduced transportation cost, improved profits, reduced environmental impact and fast-depleting reserves of conventional natural aggregates has necessitated the use of recycling, in order to be able to conserve conventional natural aggregate. In this study various physical and mechanical properties of recycled concrete aggregates were examined. Recycled concrete aggregates are different from natural aggregates and concrete made from them has specific properties. The percentages of recycled concrete aggregates were varied and it was observed that properties such as compressive strength showed a decrease of up to 10% as the percentage of recycled concrete aggregates increased. Water absorption of recycled aggregates was found to be greater than natural aggregates, and this needs to be compensated during mix design. PMID:16784165

  17. Diversity, intent, and aggregated search

    M. de Rijke

    2014-01-01

    Diversity, intent and aggregated search are three core retrieval concepts that receive significant attention. In search result diversification one typically considers the relevance of a document in light of other retrieved documents. The goal is to identify the probable "aspects" of an ambiguous que

  18. Child Labor and Aggregate Fluctuations

    Stéphane Pallage; Alice Fabre

    2010-01-01

    In this paper, we build a dynamic general equilibrium model with heterogeneous agents to measure the welfare effect of banning child labor in an economy with aggregate fluctuations and idiosyncratic shocks to employment. We then design an unemployment insurance system that generates the endogenous elimination of child labor.

  19. Progressive oxidation of pyrite in five bituminous coal samples: An As XANES and 57Fe Moessbauer spectroscopic study

    Naturally occurring pyrite commonly contains minor substituted metals and metalloids (As, Se, Hg, Cu, Ni, etc.) that can be released to the environment as a result of its weathering. Arsenic, often the most abundant minor constituent in pyrite, is a sensitive monitor of progressive pyrite oxidation in coal. To test the effect of pyrite composition and environmental parameters on the rate and extent of pyrite oxidation in coal, splits of five bituminous coal samples having differing amounts of pyrite and extents of As substitution in the pyrite, were exposed to a range of simulated weathering conditions over a period of 17 months. Samples investigated include a Springfield coal from Indiana (whole coal pyritic S = 2.13 wt.%; As in pyrite = detection limit (d.l.) to 0.06 wt.%), two Pittsburgh coal samples from West Virginia (pyritic S = 1.32-1.58 wt.%; As in pyrite = d.l. to 0.34 wt.%), and two samples from the Warrior Basin, Alabama (pyritic S = 0.26-0.27 wt.%; As in pyrite = d.l. to 2.72 wt.%). Samples were collected from active mine faces, and expected differences in the concentration of As in pyrite were confirmed by electron microprobe analysis. Experimental weathering conditions in test chambers were maintained as follows: (1) dry Ar atmosphere; (2) dry O2 atmosphere; (3) room atmosphere (relative humidity ∼20-60%); and (4) room atmosphere with samples wetted periodically with double-distilled water. Sample splits were removed after one month, nine months, and 17 months to monitor the extent of As and Fe oxidation using As X-ray absorption near-edge structure (XANES) spectroscopy and 57Fe Moessbauer spectroscopy, respectively. Arsenic XANES spectroscopy shows progressive oxidation of pyritic As to arsenate, with wetted samples showing the most rapid oxidation. 57Fe Moessbauer spectroscopy also shows a much greater proportion of Fe3+ forms (jarosite, Fe3+ sulfate, FeOOH) for samples stored under wet conditions, but much less difference among samples stored

  20. Using Information Aggregation Markets for Decision Support

    Patrick Buckley

    2012-06-01

    Full Text Available Information Aggregation Markets, often referred to as prediction markets, are markets that are designed to aggregate information from a disparate pool of human individuals to make predictions about the likely outcome of future uncertain events. This paper looks at how Information Aggregation Markets can be incorporated into the standard body of decision making theory. It examines how Information Aggregation Markets can be used as decision support systems, and provides empirical evidence from a wide variety of sources as to the effectiveness and practicality of Information Aggregation Markets. Finally, this paper details some future research questions to be addressed in the area of Information Aggregation Markets.

  1. Estimation of line efficiency by aggregation

    Koster, de, MBM René

    1987-01-01

    textabstractPresents a multi-stage flow lines with intermediate buffers approximated by two-stage lines using repeated aggregation. Characteristics of the aggregation method; Problems associated with the analysis and design of production lines.

  2. Aggregation of metallochlorophylls - Examination by spectroscopy

    Boucher, L. J.; Katz, J. J.

    1969-01-01

    Nuclear magnetic resonance measurements determine which metallochlorophylls, besides magnesium-containing chlorophylls, possess coordination aggregation properties. Infrared spectroscopy reveals that only zinc pheophytin and zinc methyl pheophorbide showed significant coordination aggregation, whereas divalent nickel and copper did not.

  3. Yeast prions: protein aggregation is not enough.

    Sherman, Michael Y

    2004-01-01

    Although many proteins -- both damaged and normal -- have a tendency to aggregate, only some are capable of dividing and propagating. What does it take to turn a protein aggregate into an infectious prion?

  4. Estimation of Line Efficiency by Aggregation

    M.B.M. de Koster (René)

    1987-01-01

    textabstractPresents a multi-stage flow lines with intermediate buffers approximated by two-stage lines using repeated aggregation. Characteristics of the aggregation method; Problems associated with the analysis and design of production lines.

  5. Elections, information aggregation, and strategic voting

    Feddersen, Timothy; Pesendorfer, Wolfgang

    1999-01-01

    A central role of elections is the aggregation of information dispersed within a population. This article surveys recent work on elections as mechanisms for aggregating information and on the incentives for voters to vote strategically in such elections.

  6. Bacterial Association with Particles: Aggregation to Dissolution

    DeSouza, M.J.B.D.

    stick to phytoplankton cells to form larger particles called marine snow that enhance the sinking flux of organic carbon. However, Smith et al. (1992) and Ploug et al. (1999) found that once the bacteria colonize the aggregate they solubilize... trophic levels of the aquatic food web (Kiorboe et al., 2002). Caron et al. (1982) thought that aggregates are important loci of microbial activity in the water column, similar to the much larger oceanic ?marine snow? aggregates. Marine snow aggregates...

  7. ASSESSMENT OF FINE RECYCLED AGGREGATES IN MORTAR

    Feys, Charles; Joseph, Miquel; Boehme, Luc; Zhang, Yunlian

    2016-01-01

    In this study, the influence of fine recycled concrete aggregates as replacement for sand in mortar and the use as cement replacement and filler is investigated. Mortar with fine recycled aggregates is examined on its mechanical and physical properties. The samples are also examined on a microscopic scale. The fine recycled concrete aggregates are made with one-year old concrete made in the laboratory. Fine recycled aggregates (FRCA) are added as a cement replacement (0 %, 10 %...

  8. Revisiting Aggregation Techniques for Data Intensive Applications

    Wen, Jian

    2013-01-01

    Aggregation has been an important operation since the early days of relational databases. Today's Big Data applications bring further challenges when processing aggregation queries, demanding robust aggregation algorithms that can process large volumes of data efficiently in a distributed, share-nothing architecture. Moreover, aggregation on each node runs under a potentially limited memory budget (especially in multiuser settings). Despite its importance, the design and evaluation of aggrega...

  9. Computers and Productivity: Are Aggregation Effects Important?

    Robert H. McGuckin; Kevin Stiroh

    2000-01-01

    This paper examines the empirical implications of aggregation bias when measuring the productive impact of computers. To isolate two specific aggregation problems relating to "aggregation in variables" and "aggregation in relations," we compare various production function estimates across a range of specifications, econometric estimators, and data levels. The results show that both sources of bias are important, especially as one moves from the sector to the economy level, and when the elasti...

  10. Internal water curing with Liapor aggregates

    Lura, Pietro

    2005-01-01

    Internal water curing is a very efficient way to counteract self-desiccation and autogenous shrinkage in high performance concrete, thereby reducing the likelihood of early-age cracking. This paper deals with early-age volume changes and moisture transport in lightweight aggregate concrete realized...... with wet lightweight aggregates. Lightweight aggregate concrete mixtures with different degree of saturation and different particle size of the lightweight aggregates were studied and compared to normal weight concrete. Autogenous deformations, selfinduced stresses in fully restrained conditions...

  11. Aggregation resistant zwitterated superparamagnetic nanoparticles

    Superparamagnetic nanoparticles (NPs) are promising for biomedical applications since they can be directed toward the organ of interest using an external magnetic field. They are also good contrast agents for magnetic resonance imaging and have potential for the treatment of malignant tumors (i.e., hyperthermia). Therefore, there is a need to produce stable, non-aggregating superparamagnetic nanomaterials that can withstand the in vivo environment. In this work, the colloidal stability of a dispersion of iron oxide NPs was enhanced by functionalizing them with a short zwitterionic siloxane shell in aqueous media. The stabilization procedure yields superparamagnetic nanomaterials, ca. 10 nm in diameter, with saturation magnetization of about 54 emu/g that resist aggregation at physiological salt concentration, temperature, and pH. The loading of the zwitterionic shell was established with diffuse reflectance infrared spectroscopy and thermal gravimetric analysis. X-ray and electron diffraction verified the starting magnetite phase, and that no change in phase occurred on surface functionalization.

  12. Aggregating and Disaggregating Flexibility Objects

    Siksnys, Laurynas; Valsomatzis, Emmanouil; Hose, Katja;

    2015-01-01

    In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts...... of such objects while preserving flexibility. Hence, this paper formally defines the concept of flexibility objects (flex-objects) and provides a novel and efficient solution for aggregating and disaggregating flex-objects. Out of the broad range of possible applications, this paper will focus on smart grid...... energy data management and discuss strategies for aggregation and disaggregation of flex-objects while retaining flexibility. This paper further extends these approaches beyond flex-objects originating from energy consumption by additionally considering flex-objects originating from energy production...

  13. Containing Internal Diffusion Limited Aggregation

    Duminil-Copin, Hugo; Yadin, Ariel; Yehudayoff, Amir

    2011-01-01

    Internal Diffusion Limited Aggregation (IDLA) is a model that describes the growth of a random aggregate of particles from the inside out. Shellef proved that IDLA processes on supercritical percolation clusters of integer-lattices fill Euclidean balls, with high probability. In this article, we complete the picture and prove a limit-shape theorem for IDLA on such percolation clusters, by providing the corresponding upper bound. The technique to prove upper bounds is new and robust: it only requires the existence of a "good" lower bound. Specifically, this way of proving upper bounds on IDLA clusters is more suitable for random environments than previous ways, since it does not harness harmonic measure estimates.

  14. Recycled aggregate concrete; an overview

    Sorato, Renan

    2016-01-01

    The aim of this Bachelor’s thesis was to investigate whether recycled materials can be incorporated into the production of concrete without compromising the compressive strength of the concrete produced. In order to shed light on the compressive strength of concrete made from recycled materials, the thesis reviewed studies in which waste materials are utilised as recycled aggregates in the composition of concrete and presented the results of this synthesis and analysis. It was found that som...

  15. Judgment aggregation functions and ultraproducts

    Herzberg, Frederik

    2011-01-01

    The relationship between propositional model theory and social decision making via premise-based procedures is explored. A one-to-one correspondence between ultrafilters on the population set and weakly universal, unanimity-respecting, systematic judgment aggregation functions is established. The proof constructs an ultraproduct of profiles, viewed as propositional structures, with respect to the ultrafilter of decisive coalitions. This representation theorem can be used to prove other proper...

  16. Underground economy and aggregate fluctuations

    Juan Carlos Conesa Roca; Carlos Díaz Moreno; José Enrique Galdón Sánchez

    2001-01-01

    This paper explores the role of underground economic activities as an explanation of differences in registered aggregate fluctuations. In order to do so, we introduce an underground economy sector in an otherwise standard Real Business Cycle model and calibrate it to the USA economy. We find that, at low frequencies, Europe fluctuates more than the USA, while its participation rate is smaller. The existence of underground activities rationalizes the negative relationship between participation...

  17. Credit contagion and aggregate losses

    Giesecke, Kay; Weber, Stefan

    2002-01-01

    Credit contagion refers to the propagation of economic distress from one firm or sovereign government to another. In this paper we model credit contagion phenomena and study the fluctuation of aggregate credit losses on large portfolios of financial positions. The joint dynamics of firms’ credit ratings is modeled by a voter process, which is well-known in the theory of interacting particle systems. We clarify the structure of the equilibrium joint rating distribution using ergodic decomposit...

  18. Aggregating Labels in Crowdsourcing Data

    Priisalu, Maria; Grey, Francois; Segal, Ben

    2015-01-01

    Project Specification Crowdsourcing is gaining popularity in academia with the launch of crowdsourcing platforms such as Crowdcrafting [Lombraña, 2015] and GeoTagX [UNOSAT, 2015]. There have been a number of proposed algorithms for the aggregation of true labels and a confusion matrix from crowdsourced labels for ordinal, nominal and binary labels. The work here consists of an implementation of the Dawid Skene [Dawid 1979] adaptation of the Expectation Maximization algorithm [D...

  19. Protein aggregates in Huntington's disease

    Arrasate, M.; Finkbeiner, S

    2011-01-01

    Huntington's disease (HD) is an incurable neurodegenerative disease characterized by abnormal motor movements, personality changes, and early death. HD is caused by a mutation in the IT-15 gene that expands abnormally the number of CAG nucleotide repeats. As a result, the translated protein huntingtin contains disease-causing expansions of glutamines (polyQ) that make it prone to misfold and aggregate. While the gene and mutations that cause HD are known, the mechanisms underlying HD pathogen...

  20. Intuitionistic fuzzy aggregation and clustering

    Xu, Zeshui

    2012-01-01

    This book offers a systematic introduction to the clustering algorithms for intuitionistic fuzzy values, the latest research results in intuitionistic fuzzy aggregation techniques, the extended results in interval-valued intuitionistic fuzzy environments, and their applications in multi-attribute decision making, such as supply chain management, military system performance evaluation, project management, venture capital, information system selection, building materials classification, and operational plan assessment, etc.

  1. Belt conveyor for recycle aggregate

    Bezrodný, Roman

    2014-01-01

    This bachelor thesis deals with the belt conveyor for the transport of recycled aggregate in an oblique direction. The aim is to find constructional solutions to the belt conveyor for the assigned transport capacity of 95 000 kg per hour, and the assigned axial distance of 49 m and different height of 12 m. The thesis contains a brief description of the belt conveyor and a description of basic constructional components. It also contains a functional calculation of the capacity and forces acco...

  2. Aggregate Uncertainty, Money and Banking

    Hongfei Sun

    2006-01-01

    This paper studies the problem of monitoring the monitor in a model of money and banking with aggregate uncertainty. It shows that when inside money is required as a means of bank loan repayment, a market of inside money is entailed at the repayment stage and generates information-revealing prices that perfectly discipline the bank. The incentive problem of a bank is costlessly overcome simply by involving inside money in repayment. Inside money distinguishes itself from outside money by its ...

  3. Economic Instability and Aggregate Investment

    Robert S. Pindyck; Solimano, Andres

    1993-01-01

    Recent literature suggests that because investment expenditures are irreversible and can be delayed, they may be highly sensitive to uncertainty. The authors briefly summarize the theory, stressing its empirical implications. Then, using cross-section and time-series data for a set of developing and industrial countries, they explore the empirical relevance of irreversibility and uncertainty to aggregate investment. They find that: (a) the volatility of the marginal profitability of capital (...

  4. Parametric characterization of aggregation functions

    Mesiar, Radko; Kolesárová, A.

    2009-01-01

    Roč. 160, č. 6 (2009), s. 816-831. ISSN 0165-0114 R&D Projects: GA ČR GA402/08/0618 Institutional research plan: CEZ:AV0Z10750506 Keywords : Aggregation function * Conjunction measure * Disjunction measure * Global/local parametric characterization * Idempotency measure Subject RIV: BA - General Mathematics Impact factor: 2.138, year: 2009 http://library.utia.cas.cz/separaty/2009/E/mesiar-parametriccharacterizationofaggregationfunctions.pdf

  5. 78 FR 68945 - Aggregation of Positions

    2013-11-15

    ... (``1979 Aggregation Policy''), 44 FR 33839, 33843 (June 13, 1979). Note, however, that consistent with the... the ownership criteria of aggregation. \\40\\ See, e.g., 53 FR 13290, 13292 (1988) (proposal). The 1988... approach best resolves those issues while maintaining a bright-line aggregation test? \\41\\ See 77 FR...

  6. Aggregation functions: an approach using copulae

    Marta Cardin; Maddalena Manzi

    2007-01-01

    In this paper we present the extension of the copula approach to aggregation functions. In fact we want to focus on a class of aggregation functions and present them in the multilinear form with marginal copulae. Moreover, we define the joint aggregation density function.

  7. 28 CFR 2.5 - Sentence aggregation.

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Sentence aggregation. 2.5 Section 2.5 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS... aggregation. When multiple sentences are aggregated by the Bureau of Prisons pursuant to 18 U.S.C. 4161...

  8. Aggregated Authentication (AMAC) Using Universal Hash Functions

    Znaidi, Wassim; Minier, Marine; Lauradoux, Cédric

    Aggregation is a very important issue to reduce the energy consumption in Wireless Sensors Networks (WSNs). There is currently a lack of cryptographic primitives for authentication of aggregated data. The theoretical background for Aggregated Message Authentication Codes (AMACs) has been proposed by Chan and Castelluccia at ISIT 08.

  9. Aggregation of erythrocytes in burn disease

    Levin, Grigory Y; Egorihina, Marpha N

    2011-01-01

    The manuscript describes experiments designed to examine factors that influence erythrocytes aggregation within the blood of burn patients. Results showed that the rate and degree of erythrocytes aggregation increased significantly in burn patients, and what is especially unfavorable for microcirculation, erythrocytes disaggregation decreased. We show that normalization of blood plasma contents completely restores erythrocytes aggregation and disaggregation of burn patients. The rate and degr...

  10. Network Provisioning Using Multimedia Aggregates

    Joan Vila-Carbó

    2008-01-01

    Full Text Available Multimedia traffic makes network provisioning a key issue. Optimal provisioning of network resources is crucial for reducing the service cost of multimedia transmission. Multimedia traffic requires not only provisioning bandwidth and buffer resources in the network but also guaranteeing a given maximum end-to-end delay. In this paper we present methods and tools for the optimal dimensioning of networks based on multimedia aggregates. The proposed method minimises the network resources reservations of traffic aggregates providing a bounded delay. The paper also introduces several methods to generate multimedia traffic aggregation using real video traces. The method is evaluated using a network topology based on the European GÉANT network. The results of these simulations allow us to discover the relationship between a required delay and the necessary bandwidth reservation (or the achievable utilisation limit. An interesting conclusion of these scenarios is that, following several recommendations, the network utilisation can reach values of around 80% or higher.

  11. Osmosis-induced water uptake by Eurobitum bituminized radioactive waste and pressure development in constant volume conditions

    Marieen, A., E-mail: amarien@sckcen.be [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Mokni, N., E-mail: Nadia.mokni@upc.edu [Department of Geotechnical Engineering and Geosciences, Universidad Politecnica de Catalunya (UPC), Calle Gran Capitan, s/n, Edificio C-1, 08034 Barcelona (Spain); Valcke, E. [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Olivella, S. [Department of Geotechnical Engineering and Geosciences, Universidad Politecnica de Catalunya (UPC), Calle Gran Capitan, s/n, Edificio C-1, 08034 Barcelona (Spain); Smets, S. [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Li, X., E-mail: xli@sckcen.be [EIG EURIDICE, Boeretang 200, 2400 Mol (Belgium)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer The water uptake by Eurobitum is studied to judge the safety of geological disposal. Black-Right-Pointing-Pointer High pressures of up to 20 MPa are measured in constant volume water uptake tests. Black-Right-Pointing-Pointer The morphology of leached Eurobitum samples is studied with {mu}CT and ESEM. Black-Right-Pointing-Pointer The observations are reproduced by an existing CHM formulation for Eurobitum. - Abstract: The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at Belgian Nuclear Research Center SCK-CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluna, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO{sub 3} leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography ({mu}CT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to

  12. Dike intrusions into bituminous coal, Illinois Basin: H, C, N, O isotopic responses to rapid and brief heating

    Schimmelmann, A.; Mastalerz, Maria; Gao, L.; Sauer, P.E.; Topalov, K.

    2009-01-01

    Unlike long-term heating in subsiding sedimentary basins, the near-instantaneous thermal maturation of sedimentary organic matter near magmatic intrusions is comparable to artificial thermal maturation in the laboratory in terms of short duration and limited extent. This study investigates chemical and H, C, N, O isotopic changes in high volatile bituminous coal near two Illinois dike contacts and compares observed patterns and trends with data from other published studies and from artificial maturation experiments. Our study pioneers in quantifying isotopically exchangeable hydrogen and measuring the D/H (i.e., 2H/1H) ratio of isotopically non-exchangeable organic hydrogen in kerogen near magmatic contacts. Thermal stress in coal caused a reduction of isotopically exchangeable hydrogen in kerogen from 5% to 6% in unaltered coal to 2-3% at contacts, mostly due to elimination of functional groups (e.g., {single bond}OH, {single bond}COOH, {single bond}NH2). In contrast to all previously published data on D/H in thermally matured organic matter, the more mature kerogen near the two dike contacts is D-depleted, which is attributed to (i) thermal elimination of D-enriched functional groups, and (ii) thermal drying of hydrologically isolated coal prior to the onset of cracking reactions, thereby precluding D-transfer from relatively D-enriched water into kerogen. Maxima in organic nitrogen concentration and in the atomic N/C ratio of kerogen at a distance of ???2.5 to ???3.5 m from the thicker dike indicate that reactive N-compounds had been pyrolytically liberated at high temperature closer to the contact, migrated through the coal seam, and recombined with coal kerogen in a zone of lower temperature. The same principle extends to organic carbon, because a strong ??13Ckerogen vs. ??15Nkerogen correlation across 5.5 m of coal adjacent to the thicker dike indicates that coal was functioning as a flow-through reactor along a dynamic thermal gradient facilitating back

  13. Osmosis-induced water uptake by Eurobitum bituminized radioactive waste and pressure development in constant volume conditions

    Mariën, A.; Mokni, N.; Valcke, E.; Olivella, S.; Smets, S.; Li, X.

    2013-01-01

    The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at the Belgian Nuclear Research Center SCK•CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluña, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO3 leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography (μCT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to values that can be (in theory) as high as 42.8 MPa, being the osmotic pressure of a saturated NaNO3 solution. After about four years of hydration in nearly constant volume water uptake tests, pressures up to 20 MPa are measured. During this hydration period only the outer layers with a thickness of 1-2 mm were hydrated (as derived from μCT and ESEM analyses), and only about 10-20% of the initial NaNO3 content was released by the samples. In the studied test

  14. Dike intrusions into bituminous coal, Illinois Basin: H, C, N, O isotopic responses to rapid and brief heating

    Schimmelmann, Arndt; Mastalerz, Maria; Gao, Ling; Sauer, Peter E.; Topalov, Katarina

    2009-10-01

    Unlike long-term heating in subsiding sedimentary basins, the near-instantaneous thermal maturation of sedimentary organic matter near magmatic intrusions is comparable to artificial thermal maturation in the laboratory in terms of short duration and limited extent. This study investigates chemical and H, C, N, O isotopic changes in high volatile bituminous coal near two Illinois dike contacts and compares observed patterns and trends with data from other published studies and from artificial maturation experiments. Our study pioneers in quantifying isotopically exchangeable hydrogen and measuring the D/H (i.e., 2H/ 1H) ratio of isotopically non-exchangeable organic hydrogen in kerogen near magmatic contacts. Thermal stress in coal caused a reduction of isotopically exchangeable hydrogen in kerogen from 5% to 6% in unaltered coal to 2-3% at contacts, mostly due to elimination of functional groups (e.g., sbnd OH, sbnd COOH, sbnd NH 2). In contrast to all previously published data on D/H in thermally matured organic matter, the more mature kerogen near the two dike contacts is D-depleted, which is attributed to (i) thermal elimination of D-enriched functional groups, and (ii) thermal drying of hydrologically isolated coal prior to the onset of cracking reactions, thereby precluding D-transfer from relatively D-enriched water into kerogen. Maxima in organic nitrogen concentration and in the atomic N/C ratio of kerogen at a distance of ˜2.5 to ˜3.5 m from the thicker dike indicate that reactive N-compounds had been pyrolytically liberated at high temperature closer to the contact, migrated through the coal seam, and recombined with coal kerogen in a zone of lower temperature. The same principle extends to organic carbon, because a strong δ13C kerogen vs. δ15N kerogen correlation across 5.5 m of coal adjacent to the thicker dike indicates that coal was functioning as a flow-through reactor along a dynamic thermal gradient facilitating back-reactions between mobile

  15. Evaluation of crushed aggregate and sand-bentonite mixtures for application to sealing of the final repository for reactor waste

    The Industrial Power Company Ltd (TVO) is planning to dispose the low- and intermediate level waste from the reactors of the Olkiluoto Nuclear Power Station into the bedrock of Olkiluoto at a depth of approximately 50-100 meters. In the TVO concept the reactor waste is disposed in silo shaped rock caverns. The bituminized waste is packed into steel drums, which are laid into a concrete silo inside the rock cavern. In this study the properties of sands, crushed aggregate and their mixtures with bentonite are reviewed. The applicability of these materials for use as a buffer on the top of the concrete silo is evaluated. This study is based on earlier experimental studies of the materials mentioned before and available literature. Gas production in the silo after disposal is estimated. General concepts of gas conductivity and gas migration in saturated soil are reviewed. The results of this study suggest that crushed aggregate and sand-bentonite mixtures are possible sealing materials for the silo in concern. But the need for further experimental study of their physical and mechanical properties and the gas migration processes through the saturated barrier is emphasized. A program for testing of these properties is presented

  16. [AGGREGATION OF METABOLICALLY DEPLETED HUMAN ERYTHROCYTES].

    Sheremet'ev, Yu A; Popovicheva, A N; Rogozin, M M; Levin, G Ya

    2016-01-01

    An aggregation of erythrocytes in autologous plasma after blood storage for 14 days at 4 °C was studied using photometry and light microscopy. The decrease of ATP content, the formation of echinocytes and spheroechinocytes, the decrease of rouleaux form of erythrocyte aggregation were observed during the storage. On the other hand the aggregates of echinocytes were formed in the stored blood. The addition of plasma from the fresh blood didn't restore the normal discocytic shape and aggregation of erythrocytes in the stored blood. The possible mechanisms of erythrocytes and echinocytes aggregation are discussed. PMID:27220249

  17. [Lysophosphatidic acid and human erythrocyte aggregation].

    Sheremet'ev, Iu A; Popovicheva, A N; Levin, G Ia

    2014-01-01

    The effects of lysophosphatidic acid on the morphology and aggregation of human erythrocytes has been studied. Morphology of erythrocytes and their aggregates were studied by light microscopy. It has been shown that lysophosphatidic acid changes the shape of red blood cells: diskocyte become echinocytes. Aggregation of red blood cells (rouleaux) was significantly reduced in autoplasma. At the same time there is a strong aggregation of echinocytes. This was accompanied by the formation of microvesicles. Adding normal plasma to echinocytes restores shape and aggregation of red blood cells consisting of "rouleaux". A possible mechanism of action of lysophosphatidic acid on erythrocytes is discussed. PMID:25509147

  18. Aggregation of Diesel Contaminated Soil for Bioremediation

    Yu Ying; Shi Xiu-hong; Li Song; Xu Jing-gang

    2014-01-01

    Diesel contaminated soil (DCS) contained a large amount of the hydrocarbons and salt which was dominated by soluble sodium chloride. Aggregation process which made the desired aggregate size distribution could speed up the degradation rate of the hydrocarbons since the aggregated DCS had better physical characteristics than the non-aggregated material. Artificial aggregation increased pores >30 µm by approximately 5% and reduced pores <1 µm by 5%, but did not change the percentage of the pores between 1 and 30 µm. The saturated hydraulic conductivity of non-aggregated DCS was 5×10-6 m• s-l, but it increased to 1×10-5 m• s-l after aggregation. The compression index of the non-aggregated DCS was 0.0186; however, the artificial aggregates with and without lime were 0.031 and 0.028, respectively. DCS could be piled 0.2 m deep without artificial aggregation; however, it could be applied 0.28 m deep when artificial aggregates were formed without limiting O2 transport.

  19. Bouncing Behavior of Microscopic Dust Aggregates

    Seizinger, Alexander

    2013-01-01

    Context: Bouncing collisions of dust aggregates within the protoplanetary may have a significant impact on the growth process of planetesimals. Yet, the conditions that result in bouncing are not very well understood. Existing simulations studying the bouncing behavior used aggregates with an artificial, very regular internal structure. Aims: Here, we study the bouncing behavior of sub-mm dust aggregates that are constructed applying different sample preparation methods. We analyze how the internal structure of the aggregate alters the collisional outcome and determine the influence of aggregate size, porosity, collision velocity, and impact parameter. Methods: We use molecular dynamics simulations where the individual aggregates are treated as spheres that are made up of several hundred thousand individual monomers. The simulations are run on GPUs. Results: Statistical bulk properties and thus bouncing behavior of sub-mm dust aggregates depend heavily on the preparation method. In particular, there is no uni...

  20. An exact approach for aggregated formulations

    Gamst, Mette; Spoorendonk, Simon

    Aggregating formulations is a powerful approach for transforming problems into taking more tractable forms. Aggregated formulations can, though, have drawbacks: some information may get lost in the aggregation and { put in a branch-and-bound context { branching may become very di_cult and even...... mathematical formulation and the aggregated formulation. The method allows usage of relaxed aggregated formulations and enables branching on both aggregated and disaggregated variables. Also, the method guarantees an LP bound at least as good as those for the disaggregated and aggregated formulations. The...... paper includes general considerations on types of problems for which the method is of particular interest. Furthermore, we prove the correctness of the procedure and consider how to include extensions such as cutting planes and advanced branching strategies....

  1. Microwave extinction characteristics of nanoparticle aggregates

    Wu, Y. P.; Cheng, J. X.; Liu, X. X.; Wang, H. X.; Zhao, F. T.; Wen, W. W.

    2016-07-01

    Structure of nanoparticle aggregates plays an important role in microwave extinction capacity. The diffusion-limited aggregation model (DLA) for fractal growth is utilized to explore the possible structures of nanoparticle aggregates by computer simulation. Based on the discrete dipole approximation (DDA) method, the microwave extinction performance by different nano-carborundum aggregates is numerically analyzed. The effects of the particle quantity, original diameter, fractal structure, as well as orientation on microwave extinction are investigated, and also the extinction characteristics of aggregates are compared with the spherical nanoparticle in the same volume. Numerical results give out that proper aggregation of nanoparticle is beneficial to microwave extinction capacity, and the microwave extinction cross section by aggregated granules is better than that of the spherical solid one in the same volume.

  2. Credit, Money, and Aggregate Demand

    Bernanke, Ben S.; Alan S. Blinder

    1988-01-01

    Standard models of aggregate demand treat money and credit asymmetrically; money is given a special status, while loans, bonds, and other debt instruments are lumped together in a "bond market" and suppressed by Walras' Law. This makes bank liabilities central to the monetary transmission mechanism, while giving no role to bank assets. We show how to modify a textbook IS-UI model so as to permit a more balanced treatment. As in Tobin (1969) and Brunner-Meltzer (1972), the key assumption is th...

  3. Strategy-proof Preference Aggregation

    Bossert, Walter; Sprumont, Yves

    2012-01-01

    An aggregation rule maps each profile of individual strict preference orderings over a set of alternatives into a social ordering over that set. We call such a rule strategyproof if misreporting one’s preference never produces a social ordering that is strictly between the original ordering and one’s own preference. After describing a few examples of manipulable rules, we study in some detail three classes of strategy-proof rules: (i) rules based on a monotonic alteration of the majority rela...

  4. Inhomogeneous diffusion-limited aggregation

    Selinger, Robin Blumberg; Nittmann, Johann; Stanley, H. E.

    1989-01-01

    It is demonstrated here that inhomogeneous diffusion-limited aggregation (DLA) model can be used to simulate viscous fingering in a medium with inhomogeneous permeability and homogeneous porosity. The medium consists of a pipe-pore square-lattice network in which all pores have equal volume and the pipes have negligible volume. It is shown that fluctuations in a DLA-based growth process may be tuned by noise reduction, and that fluctuations in the velocity of the moving interface are multiplicative in form.

  5. PERCOLATION OF RANDOM CYLINDER AGGREGATES

    Dominique Jeulin

    2011-05-01

    Full Text Available The percolation threshold ρc of Boolean models of cylinders with their axis parallel to a given direction is studied by means of simulations. An efficient method of construction of percolating connected components was developed, and is applied to one or two scales Boolean model, in order to simulate the presence of aggregates. The invariance of the percolation threshold with respect to affine transformations in the common direction of the axis of cylinders is approximately satisfied on simulations. The prediction of the model (ρc close to 0.16 is consistent with experimental measurements on plasma spray coatings, which motivated this study.

  6. Utilization Possibility of Natural Aggregate Resources in Central Town of Tokat as Concrete Aggregate

    S. I. Tutmaz

    2010-01-01

    Full Text Available In this study, aggregates of three quarries sampled from Tokat Province were tested to evaluate their suitability for concrete production. The aggregates were supplied from Yesilirmak River, and largely used in agricultural structures constructed in Tokat. Standard aggregate tests approved by Turkish Standards Institute were carried out to analyze the samples. Granulation, unit weight, specific weight, water absorption rate, resistance to frost, resistance against abrasion, ratio of fine materials, organic material contents and, mineralogical analysis of aggregates sampled from aggregate quarries were determined. Pressure resistance tests were conducted on concrete prepared by the aggregates. The results indicated that the aggregate granulation distribution of aggregate quarries evaluated was not suitable however other parameters determined were appropriate for concrete production. The resultant concrete had sufficient pressure resistance. The possible solutions to improve the improper characteristics of aggregates used in concrete were also determined and introduced with this study.

  7. Spanish Round Robin test on water sensitivity test of bituminous mixtures; Ejercicio espanol interlaboratorios sobre el ensayo de sensibilidad al gua de mezclas bituminosas

    Jimenez Saez, R.; Enrique Gabeiras, L.; Miranda Perez, L.; Valor Hernandez, F.

    2011-07-01

    The amendment of Article 542 and 543 on the hot asphalt mixtures included in the Spanish Technical specifications for Road Construction (PG-3), by Circular Order 24/2008, introduced a new series of modification to adapt Spanish regulations to European standards series EN 13108. Among the various amendments, new tests methods and design criteria are considered, as UNE-EN 12697-12 for assessing the water sensitivity on compacted specimens, which is mandatory for every kind of bituminous mixture. In this paper, firstly a comparison between the European method and the old Spanish method described in the NLT-162 is made, explaining the experimental conditions selected. The results of an interlaboratory study or Round Robin Test conducted in ten Spanish laboratories are subsequently described and analyzed, in order to allow each laboratory to assess its technical performance, and also to determine quantitatively the precision of the new method in terms of repeatability and reproducibility. (Author) 15 refs.

  8. Protein aggregates in Huntington's disease.

    Arrasate, Montserrat; Finkbeiner, Steven

    2012-11-01

    Huntington's disease (HD) is an incurable neurodegenerative disease characterized by abnormal motor movements, personality changes, and early death. HD is caused by a mutation in the IT-15 gene that expands abnormally the number of CAG nucleotide repeats. As a result, the translated protein huntingtin contains disease-causing expansions of glutamines (polyQ) that make it prone to misfold and aggregate. While the gene and mutations that cause HD are known, the mechanisms underlying HD pathogenesis are not. Here we will review the state of knowledge of HD, focusing especially on a hallmark pathological feature-intracellular aggregates of mutant Htt called inclusion bodies (IBs). We will describe the role of IBs in the disease. We speculate that IB formation could be just one component of a broader coping response triggered by misfolded Htt whose efficacy may depend on the extent to which it clears toxic forms of mutant Htt. We will describe how IB formation might be regulated and which factors could determine different coping responses in different subsets of neurons. A differential regulation of IB formation as a function of the cellular context could, eventually, explain part of the neuronal vulnerability observed in HD. PMID:22200539

  9. Mercury emissions during cofiring of sub-bituminous coal and biomass (chicken waste, wood, coffee residue, and tobacco stalk) in a laboratory-scale fluidized bed combustor

    Yan Cao; Hongcang Zhou; Junjie Fan; Houyin Zhao; Tuo Zhou; Pauline Hack; Chia-Chun Chan; Jian-Chang Liou; Wei-ping Pan [Western Kentucky University (WKU), Bowling Green, KY (USA). Institute for Combustion Science and Environmental Technology (ICSET)

    2008-12-15

    Four types of biomass (chicken waste, wood pellets, coffee residue, and tobacco stalks) were cofired at 30 wt % with a U.S. sub-bituminous coal (Powder River Basin Coal) in a laboratory-scale fluidized bed combustor. A cyclone, followed by a quartz filter, was used for fly ash removal during tests. The temperatures of the cyclone and filter were controlled at 250 and 150{sup o}C, respectively. Mercury speciation and emissions during cofiring were investigated using a semicontinuous mercury monitor, which was certified using ASTM standard Ontario Hydra Method. Test results indicated mercury emissions were strongly correlative to the gaseous chlorine concentrations, but not necessarily correlative to the chlorine contents in cofiring fuels. Mercury emissions could be reduced by 35% during firing of sub-bituminous coal using only a quartz filter. Cofiring high-chlorine fuel, such as chicken waste (Cl = 22340 wppm), could largely reduce mercury emissions by over 80%. When low-chlorine biomass, such as wood pellets (Cl = 132 wppm) and coffee residue (Cl = 134 wppm), is cofired, mercury emissions could only be reduced by about 50%. Cofiring tobacco stalks with higher chlorine content (Cl = 4237 wppm) did not significantly reduce mercury emissions. Gaseous speciated mercury in flue gas after a quartz filter indicated the occurrence of about 50% of total gaseous mercury to be the elemental mercury for cofiring chicken waste, but occurrence of above 90% of the elemental mercury for all other cases. Both the higher content of alkali metal oxides or alkali earth metal oxides in tested biomass and the occurrence of temperatures lower than 650{sup o}C in the upper part of the fluidized bed combustor seemed to be responsible for the reduction of gaseous chlorine and, consequently, limited mercury emissions reduction during cofiring. 36 refs., 3 figs. 1 tab.

  10. Asphaltene Aggregation and Fouling Behavior

    Derakhshesh, Marzie

    This thesis explored the properties of asphaltene nano-aggregates in crude oil and toluene based solutions and fouling at process furnace temperatures, and the links between these two phenomena. The link between stability of asphaltenes at ambient conditions and fouling at the conditions of a delayed coker furnace, at over 450 °C, was examined by blending crude oil with an aliphatic diluent in different ratios. The stability of the blends were measured using a S-value analyzer, then fouling rates were measured on electrically heated stainless steel 316 wires in an autoclave reactor. The less stable the blend, the greater the rate and extent of fouling. The most severe fouling occurred with the unstable asphaltenes. SEM imaging of the foulant illustrates very different textures, with the structure becoming more porous with lower stability. Under cross-polarized light, the coke shows the presence of mesophase in the foulant layer. These data suggest a correlation between the fouling rate at high temperature furnace conditions and the stability index of the crude oil. Three organic polysulfides were introduced to the crude oil to examine their effect on fouling. The polysulfides are able to reduce coking and carbon monoxide generation in steam crackers. The fouling results demonstrated that polysulfide with more sulfur content increased the amount of corrosion-fouling of the wire. Various additives, solvents, ultrasound, and heat were employed to attempt to completely disaggregate the asphaltene nano-aggregates in solution at room temperature. The primary analytical technique used to monitor the nano-aggregation state of the asphaltenes in solution was the UV-visible spectroscopy. The results indicate that stronger solvents, such as pyridine and quinoline, combined with ionic liquids yield a slight reduction in the apparent absorbance at longer wavelengths, indicative of a decrease in the nano-aggregate size although the magnitude of the decrease is not significant

  11. One-dimensional long-range diffusion-limited aggregation III -- The limit aggregate

    Amir, Gideon

    2009-01-01

    In this paper we study the structure of the limit aggregate (the union of all finite-time aggregates) of the one-dimensional long range diffusion limited aggregation process defined in [arXiv:0910.4416] . We show (under some regularity conditions) that for walks with finite third moment the limit aggregate has renewal structure and positive density, while for walks with finite variance the renewal structure no longer exists and the limit aggregate has 0 density. We define a tree structure on the aggregates and show some results on the degrees and number of ends of these random trees.

  12. chemo-Hydro-mechanical modelling of in-situ disposal of a bituminized radioactive waste in boom clay

    Document available in extended abstract form only. The current reference solution of the Belgian Agency for the Management of Radioactive Waste and Fissile Materials (ONDRAF/NIRAS) envisages underground disposal of Eurobitum Bituminized radioactive Waste (BW) in a geologically stable clay formation. In Belgium, the Boom Clay, which is a 30 to 35 million years old and ∼100 m thick marine sediment is being studied as a potential host formation because of its favorable properties to limit and delay the migration of the leached radionuclides to the biosphere over extended periods of time. The current disposal concept foresees that several drums (220 litres) of Eurobitum would be grouped in thick-walled cement-based secondary containers, which in turn would be placed in concrete-lined disposal galleries that are excavated at mid-depth in the clay layer. Only 80-90 % of the total volume of the drum is filled with Eurobitum.The remaining voids between the containers would be backfilled with a cement-based material. The interaction between the BW and the host clay formation is a very complicated chemo-hydro-mechanical process and depends not only on the hydro-mechanical behaviour of the Boom Clay itself, but also on that of the BW. In fact, the osmosis-induced uptake of water by the dehydrated hygroscopic salts embedded in the waste induces a geo-mechanical perturbation of the host formation, caused by the swelling and the increase of the pressure in and around the waste. The objectives of the Chemo-Hydro-Chemical (CHM) analysis presented in this work are (i) to get insights on the kinetics of water uptake by BW, dissolution of the embedded NaNO3 crystals, solute leaching, and maximum generated pressure under disposal conditions and (ii) to study the stress redistribution due to the recompression of the clay around a gallery caused by the swelling pressure of the bitumen and the admissible swelling pressure for Boom clay. Firstly, a CHM formulation of chemically and

  13. A vertically resolved model for phytoplankton aggregation

    Iris Kriest; Geoffrey T Evans

    2000-12-01

    This work presents models of the vertical distribution and flux of phytoplankton aggregates, including changes with time in the distribution of aggregate sizes and sinking speeds. The distribution of sizes is described by two parameters, the mass and number of aggregates, which greatly reduces the computational cost of the models. Simple experiments demonstrate the effects of aggregation on the timing and depth distribution of primary production and export. A more detailed ecological model is applied to sites in the Arabian Sea; it demonstrates that aggregation can be important for deep sedimentation even when its effect on surface concentrations is small, and it presents the difference in timing between settlement of aggregates and fecal pellets.

  14. Aggregation server for grid-integrated vehicles

    Kempton, Willett

    2015-05-26

    Methods, systems, and apparatus for aggregating electric power flow between an electric grid and electric vehicles are disclosed. An apparatus for aggregating power flow may include a memory and a processor coupled to the memory to receive electric vehicle equipment (EVE) attributes from a plurality of EVEs, aggregate EVE attributes, predict total available capacity based on the EVE attributes, and dispatch at least a portion of the total available capacity to the grid. Power flow may be aggregated by receiving EVE operational parameters from each EVE, aggregating the received EVE operational parameters, predicting total available capacity based on the aggregated EVE operational parameters, and dispatching at least a portion of the total available capacity to the grid.

  15. Influence of shear stress on erythrocyte aggregation.

    Kim, Jeong-Ho; Lee, Hoyoon; Lee, Byoung-Kwon; Shin, Sehyun

    2015-09-25

    Shear stress is known to induce platelet activation and aggregation. The red blood cell (RBC) aggregation test requires the application of shear stress for the cells to disaggregate for initialization. We tested the hypothesis that applying shear stress may activate platelets, which can influence RBC aggregation. The present study used a commercial microchip-based aggregometer (RheoSCan-AnD300) with a rotating stirrer for RBC disaggregation. Whole blood samples were exposed to different magnitudes of shear stress with various shearing times. As the rotational speed was increased up to 2800 rpm, the RBC aggregation index (AI) of the whole blood increased by up to 30% (p <  0.05), whereas that of the platelet-excluded blood samples did not show any apparent alteration. The AI also increased in proportion with the stirring time. The data suggest that high shear stress affects RBC aggregation through shear-induced platelet aggregation. PMID:26444600

  16. A dimension map for molecular aggregates.

    Jian, Cuiying; Tang, Tian; Bhattacharjee, Subir

    2015-05-01

    A pair of gyradius ratios, defined from the principal radii of gyration, are used to generate a dimension map that describes the geometry of molecular aggregates in water and in organic solvents. Molecular dynamics simulations were performed on the aggregation of representative biomolecules and polyaromatic compounds to demonstrate application of the dimension map. It was shown that molecular aggregate data on the dimension map were bounded by two boundary curves, and that the map could be separated into three regions representing three groups of structures: one-dimensional rod-like structures; two-dimensional planar structures or short-cylinder-like structures; and three-dimensional sphere-like structures. Examining the location of the aggregates on the dimension map and how the location changes with solvent type and solute material parameter provides a simple yet effective way to infer the aggregation manner and to study solubility and mechanism of aggregation. PMID:25768393

  17. Recycled aggregate concrete exposed to elevated temperature

    Arundeb Gupta; Saroj Mandal; Somnath Ghosh

    2012-01-01

    An experimental investigation has been conducted to study the mechanical as well as micro structural properties of Recycled aggregate concrete (RAC) exposed to elevated temperature. Fly ash (as replacement of cement) was added while making concrete. Recycled aggregates are mixed with natural aggregates also to prepare concrete. Cubes and cylinder test specimens were prepared and cured under water for 28 days. Test specimens were exposed to different levels of temperature (200oC, 400oC, 600oC,...

  18. Constraint Aggregation Principle in Convex Optimization

    Y.M. Ermoliev; Kryazhimskiy, A.V.; Ruszczynski, A.

    1995-01-01

    A general constraint aggregation technique is proposed for convex optimization problems. At each iteration a set of convex inequalities and linear equations is replaced by a single inequality formed as a linear combination of the original constraints. After solving the simplified subproblem, new aggregation coefficients are calculated and the iteration continues. This general aggregation principle is incorporated into a number of specific algorithms. Convergence of the new methods is pro...

  19. Linguistic Weighted Aggregation under Confidence Levels

    2015-01-01

    We develop some new linguistic aggregation operators based on confidence levels. Firstly, we introduce the confidence linguistic weighted averaging (CLWA) operator and the confidence linguistic ordered weighted averaging (CLOWA) operator. These two new linguistic aggregation operators are able to consider the confidence level of the aggregated arguments provided by the information providers. We also study some of their properties. Then, based on the generalized means, we introduce the confide...

  20. Simulations of kinetically irreversible protein aggregate structure.

    Patro, S Y; Przybycien, T M

    1994-01-01

    We have simulated the structure of kinetically irreversible protein aggregates in two-dimensional space using a lattice-based Monte-Carlo routine. Our model specifically accounts for the intermolecular interactions between hydrophobic and hydrophilic protein surfaces and a polar solvent. The simulations provide information about the aggregate density, the types of inter-monomer contacts and solvent content within the aggregates, the type and extent of solvent exposed perimeter, and the short-...

  1. Familial aggregation analysis of gene expressions

    Rao Shao-Qi; Xu Liang-De; Zhang Guang-Mei; Li Xia; Li Lin; Shen Gong-Qing; Jiang Yang; Yang Yue-Ying; Gong Bin-Sheng; Jiang Wei; Zhang Fan; Xiao Yun; Wang Qing K

    2007-01-01

    Abstract Traditional studies of familial aggregation are aimed at defining the genetic (and non-genetic) causes of a disease from physiological or clinical traits. However, there has been little attempt to use genome-wide gene expressions, the direct phenotypic measures of genes, as the traits to investigate several extended issues regarding the distributions of familially aggregated genes on chromosomes or in functions. In this study we conducted a genome-wide familial aggregation analysis b...

  2. Making Sense of the Aggregator Bank

    2009-01-01

    On Tuesday, 10 February 2009, Treasury Secretary Geithner proposed the aggregator bank (“public-private investment fund”) as a key instrument to resolve the financial crisis (www.financialstability.gov). The Treasury description leaves many issues unanswered. Here we explain how an aggregator bank might operate in practice. We fill in some of the major details so as to enhance the effectiveness of the aggregator bank. In particular, the approach emphasizes transparency and value to the taxpay...

  3. A File Aggregation Scheme for FLUTE

    Neumann, Christoph; Roca, Vincent; Walsh, Rod

    2005-01-01

    This document introduces a logical and physical file aggregation scheme for File Delivery over Unidirectional Transport (FLUTE). The logical file aggregation mechanism is a generalized grouping mechanism, allowing to logically group files. The physical file aggregation scheme allows, additionally to a logical grouping, to more efficiently use Forward Error Correction (FEC) in the context of FLUTE, in particular when dealing with a large number of "small" files. Unlike a solution based on the ...

  4. Regulated protein aggregation: stress granules and neurodegeneration

    Wolozin Benjamin

    2012-01-01

    Abstract The protein aggregation that occurs in neurodegenerative diseases is classically thought to occur as an undesirable, nonfunctional byproduct of protein misfolding. This model contrasts with the biology of RNA binding proteins, many of which are linked to neurodegenerative diseases. RNA binding proteins use protein aggregation as part of a normal regulated, physiological mechanism controlling protein synthesis. The process of regulated protein aggregation is most evident in formation ...

  5. Temporal aggregation of an ESTAR process

    I Paya; Peel, D

    2005-01-01

    Nonlinear models of deviations from PPP have recently provided an important, theoretically well motivated, contribution to the PPP puzzle. Most of these studies use temporally aggregated data to empirically estimate the nonlinear models. As noted by Taylor (2001), if the true DGP is nonlinear, the temporally aggregated data could exhibit misleading properties regarding the adjustment speeds. We examine the effects of different levels of temporal aggregation on estimates of ESTAR models of rea...

  6. Aggregate expenditure ceilings and allocative flexibility

    Marc Robinson

    2012-01-01

    This article shows how to combine top-down budgeting – in the core sense of the establishment of a hard aggregate expenditure ceiling at the start of the budget preparation process – with flexibility in the allocation of the aggregate ceiling between spending ministries during budget preparation. It argues strongly against determining spending ministry shares of the aggregate expenditure ceiling without any prior opportunity for them to present formal new spending proposals. The keys to recon...

  7. Testing aggregation consistency across geography and commodities

    Liu, Qinghua; Shumway, C. Richard

    2004-01-01

    Consistent aggregation of production data across commodities and states was tested using Lewbel's generalized composite commodity theorem (GCCT). This was the first empirical GCCT test for consistent geographic aggregation and was applied to two groups of states. Consistent commodity aggregation was tested in all states for two output groups and three input groups and in one state for a larger number of groups. Using a more powerful test procedure than previously applied to production data, m...

  8. A revised model of platelet aggregation

    Kulkarni, Suhasini; Dopheide, Sacha M.; Yap, Cindy L.; Ravanat, Catherine; Freund, Monique; Mangin, Pierre; Heel, Kathryn A.; Street, Alison; Harper, Ian S.; Lanza, Francois; Jackson, Shaun P.

    2000-01-01

    In this study we have examined the mechanism of platelet aggregation under physiological flow conditions using an in vitro flow-based platelet aggregation assay and an in vivo rat thrombosis model. Our studies demonstrate an unexpected complexity to the platelet aggregation process in which platelets in flowing blood continuously tether, translocate, and/or detach from the luminal surface of a growing platelet thrombus at both arterial and venous shear rates. Studies of platelets congenitally...

  9. Diffusion Limited Aggregation: Algorithm optimization revisited

    Braga, F. L.; Ribeiro, M. S.

    2011-08-01

    The Diffusion Limited Aggregation (DLA) model developed by Witten and Sander in 1978 is useful in modeling a large class of growth phenomena with local dependence. Besides its simplicity this aggregation model has a complex behavior that can be observed at the patterns generated. We propose on this work a brief review of some important proprieties of this model and present an algorithm to simulate a DLA aggregates that simpler and efficient compared to others found in the literature.

  10. Secure Data Aggregation in Wireless Sensor Networks

    Dr. Debmalya Bhattacharya

    2014-01-01

    The Security in sensor networks has become most important aspect along with low power as the sensors are unattended so there is more possibility of attack in WSN than usual networks, data aggregation security is an important task as if some false node injects a highly odd value it will affect the whole aggregation process, The paper reviews the need of security for data aggregation and propose an architecture which can eliminate the false values injection as well as provides e...

  11. A canonical representation for aggregated Markov processes

    Larget, Bret

    1998-01-01

    A deterministic function of a Markov process is called an aggregated Markov process. We give necessary and sufficient conditions for the equivalence of continuous-time aggregated Markov processes. For both discrete- and continuous-time, we show that any aggregated Markov process which satisfies mild regularity conditions can be directly converted to a canonical representation which is unique for each class of equivalent models, and furthermore, is a minimal parameterization ...

  12. Familial aggregation and heritability of pyloric stenosis

    Krogh, Camilla; Fischer, Thea K; Skotte, Line;

    2010-01-01

    first year of life, during which 3362 children had surgery for pyloric stenosis. MAIN OUTCOME MEASURE: Familial aggregation of pyloric stenosis, evaluated by rate ratios. RESULTS: The incidence rate (per 1000 person-years) of pyloric stenosis in the first year of life was 1.8 for singletons and 3.1 for......CONTEXT: Pyloric stenosis is the most common condition requiring surgery in the first months of life. Case reports have suggested familial aggregation, but to what extent this is caused by common environment or inheritance is unknown. OBJECTIVES: To investigate familial aggregation of pyloric...... strong familial aggregation and heritability....

  13. Aggregated Dynamic Dataflow Graph Generation and Visualization

    I. Szabó

    2013-12-01

    Full Text Available Aggregated Dynamic Dataflow Graphs can assist programmers to uncover the main data paths of a given algorithm. This information can be useful when scaling a singlethreaded program into a multi-core architecture. The amount of data movements is crucial when targeting for cache incoherent and/or heterogeneous platforms. This paper presents two methods for generating function-level Aggregated Dynamic Dataflow Graphs. Instruction level trace log was used as a basis, which was generated by Microsoft Giano processor simulator platform. Top-down aggregation strategy and relational database was used to speed up the generation of different views of the aggregated dataflow and call graphs.

  14. Microbial aggregates in anaerobic wastewater treatment.

    Kosaric, N; Blaszczyk, R

    1990-01-01

    The phenomenon aggregation of anaerobic bacteria gives an opportunity to speed up the digestion rate during methanogenesis. The aggregates are mainly composed of methanogenic bacteria which convert acetate and H2/CO2 into methane. Other bacteria are also included in the aggregates but their concentration is rather small. The aggregates may also be formed during acetogenesis or even hydrolysis but such aggregates are not stable and disrupt quickly when not fed. A two stage process seems to be suitable when high concentrated solid waste must be treated. Special conditions are necessary to promote aggregate formation from methanogenic bacteria but aggregates once formed are stable without feeding even for a few years. The structure, texture and activity of bacterial aggregates depend on several parameters: (1)--temperature and pH, (2)--wastewater composition and (3)--hydrodynamic conditions within the reactor. The common influence of all these parameters is still rather unknown but some recommendations may be given. Temperature and pH should be maintained in the range which is optimal for methanogenic bacteria e.g. a temperature between 32 and 50 degrees C and a value pH between 6.5 and 7.5. Wastewaters should contain soluble wastes and the specific loading rate should be around one kgCOD(kgVSS)-1 d-1. The concentration of the elements influences aggregate composition and probably structure and texture. At high calcium concentration a change in the colour of the granules has been observed. Research is necessary to investigate the influence of other elements and organic toxicants on maintenance of the aggregates. Hydrodynamic conditions seem to influence the stability of the granules over long time periods. At low liquid stream rates, aggregates may starve and lysis within the aggregates is possible which results in hollowing of aggregates and their floating. At high liquid stream rates the aggregates may be disrupted and washed out of the reactor as a flocculent

  15. Fracture model for cemented aggregates

    Aleksander Zubelewicz

    2013-01-01

    Full Text Available A mechanisms-based fracture model applicable to a broad class of cemented aggregates and, among them, plastic-bonded explosive (PBX composites, is presented. The model is calibrated for PBX 9502 using the available experimental data under uniaxial compression and tension gathered at various strain rates and temperatures. We show that the model correctly captures inelastic stress-strain responses prior to the load peak and it predicts the post-critical macro-fracture processes, which result from the growth and coalescence of micro-cracks. In our approach, the fracture zone is embedded into elastic matrix and effectively weakens the material's strength along the plane of the dominant fracture.

  16. Collisional Aggregation Due to Turbulence

    Pumir, Alain; Wilkinson, Michael

    2016-03-01

    Collisions between particles suspended in a fluid play an important role in many physical processes. As an example, collisions of microscopic water droplets in clouds are a necessary step in the production of macroscopic raindrops. Collisions of dust grains are also conjectured to be important for planet formation in the gas surrounding young stars and to play a role in the dynamics of sand storms. In these processes, collisions are favored by fast turbulent motions. Here we review recent advances in the understanding of collisional aggregation due to turbulence. We discuss the role of fractal clustering of particles and caustic singularities of their velocities. We also discuss limitations of the Smoluchowski equation for modeling such processes. These advances lead to a semiquantitative understanding on the influence of turbulence on collision rates and point to deficiencies in the current understanding of rainfall and planet formation.

  17. Morphological classification of nanoceramic aggregates

    Crosta, Giovanni F.; Kang, Bongwoo; Ospina, Carolina; Sung, Changmo

    2005-01-01

    Aluminum silicate nanoaggregates grown at near-room temperature on an organic template under a variety of experimental conditions have been imaged by transmission electron microscopy. Images have been automatically classified by an algorithm based on "spectrum enhancement", multivariate statistics and supervised optimization. Spectrum enhancement consists of subtracting, in the log scale, a known function of wavenumber from the angle averaged power spectral density of the image. Enhanced spectra of each image, after polynomial interpolation, have been regarded as morphological descriptors and as such submitted to principal components analysis nested with a multiobjective parameter optimization algorithm. The latter has maximized pairwise discrimination between classes of materials. The role of the organic template and of a reaction parameter on aggregate morphology has been assessed at two magnification scales. Classification results have also been related to crystal structure data derived from selected area electron diffraction patterns.

  18. Collisional Aggregation due to Turbulence

    Pumir, Alain

    2015-01-01

    Collisions between particles suspended in a fluid play an important role in many physical processes. As an example, collisions of microscopic water droplets in clouds are a necessary step in the production of macroscopic raindrops. Collisions of dust grains are also conjectured to be important for planet formation in the gas surrounding young stars, and also to play a role in the dynamics of sand storms. In these processes, collisions are favoured by fast turbulent motions. Here we review recent advances in the understanding of collisional aggregation due to turbulence. We discuss the role of fractal clustering of particles, and caustic singularities of their velocities. We also discuss limitations of the Smoluchowski equation for modelling these processes. These advances lead to a semi-quantitative understanding on the influence of turbulence on collision rates, and point to deficiencies in the current understanding of rainfall and planet formation.

  19. The use of coal refuse as construction aggregates; Utilizacion de los Esteriles de Carbon como Aridos en Construccion

    NONE

    2000-07-01

    The objective of this project was to carry out a study which would allow us to determine the nature and properties of coal refuse for its possible use as construction aggregates: roadbeds concrete, bituminous meagres, etc. and to establish criteria of acceptability, placing, and quality control. Two types of refuse, considered to be representative, were chosen (one black and one red) and various trials were performed at a grinding and classifying plant for the obtention of granular materials. The results of these trials determined the most appropriate plant treatment for each type of refuse and established the margin of acceptability, criteria of acceptability, and quality control tests to be applied to the materials obtained from coal refuse for use as construction aggregates. Laboratory testing with both types of refuse mixed with binders (cement, emulsions) were carried out. At the same time, real scale tests, through the construction of concrete slabs in local roads and in trial areas, using the proportions of aggregates and cement that are customary in the area, and also by varying the cement content, substituting it for airborne ash from the thermal La Pereda power station were also performed. From the results obtained, it can be deduced that coal refuse can be used as granular material for roadbeds in different ways: stabilised as gravel-cement, in the form of gravel emulsion, as gravel slag, or by itself. As far as its use in concrete manufacture, it is limited to marginal works. With regard to its decorative use in gardening, it is being used in various town halls in Asturias and Cantabria. (Author)

  20. Colloidal aggregation in polymer blends.

    Benhamou, M; Ridouane, H; Hachem, E-K; Derouiche, A; Rahmoune, M

    2005-06-22

    We consider here a low-density assembly of colloidal particles immersed in a critical polymer mixture of two chemically incompatible polymers. We assume that, close to the critical point of the free mixture, the colloids prefer to be surrounded by one polymer (critical adsorption). As result, one is assisted to a reversible colloidal aggregation in the nonpreferred phase, due the existence of a long-range attractive Casimir force between particles. This aggregation is a phase transition driving the colloidal system from dilute to dense phases, as the usual gas-liquid transition. We are interested in a quantitative investigation of the phase diagram of the immersed colloids. We suppose that the positions of particles are disordered, and the disorder is quenched and follows a Gaussian distribution. To apprehend the problem, use is made of the standard phi(4) theory, where the field phi represents the composition fluctuation (order parameter), combined with the standard cumulant method. First, we derive the expression of the effective free energy of colloids and show that this is of Flory-Huggins type. Second, we find that the interaction parameter u between colloids is simply a linear combination of the isotherm compressibility and specific heat of the free mixture. Third, with the help of the derived effective free energy, we determine the complete shape of the phase diagram (binodal and spinodal) in the (Psi,u) plane, with Psi as the volume fraction of immersed colloids. The continuous "gas-liquid" transition occurs at some critical point K of coordinates (Psi(c) = 0.5,u(c) = 2). Finally, we emphasize that the present work is a natural extension of that, relative to simple liquid mixtures incorporating colloids. PMID:16035822

  1. Aggregate composition and stability of structural aggregates of non-calcareous rendzinas in Eastern Serbia

    Gajić Boško; Živković Miodrag

    2006-01-01

    The present study includes the results of comparative investigations of aggregate composition and water stability of structural aggregates in humus horizons of non-calcareous rendzina under native forest and pasture vegetations and the same rendzina utilized long-term as arable field. The results show that aggregate composition and water stability of structural aggregates in the cultivated non-calcareous rendzina are significantly impaired due to a long-term anthropogenization. In the cultiva...

  2. Shrinkage of concrete with replacement of aggregate with recycled concrete aggregate

    Gómez Soberón, José Manuel Vicente

    2002-01-01

    In this paper we present the experimental analysis of samples of concrete where portion of the natural aggregate were replaced with recycled aggregate originating from concrete (RCA). Experimental analysis to obtain the shrinkage properties (basic and dried) of the concrete containing recycled concrete aggregate (CRCA) was performed. The percentages of replacement of natural aggregate with RCA were 0%, 15%, 30%, 60% and 100% with test conditions of 50% RH and 20°C. The results of these ...

  3. Towards Better Understanding of Concrete Containing Recycled Concrete Aggregate

    Hisham Qasrawi; Iqbal Marie

    2013-01-01

    The effect of using recycled concrete aggregates (RCA) on the basic properties of normal concrete is studied. First, recycled aggregate properties have been determined and compared to those of normal aggregates. Except for absorption, there was not a significant difference between the two. Later, recycled aggregates were introduced in concrete mixes. In these mixes, natural coarse aggregate was partly or totally replaced by recycled aggregates. Results show that the use of recycled aggregates...

  4. Radiation pressure cross section for fluffy aggregates

    We apply the discrete dipole approximation (DDA) to estimate the radiation pressure cross section for fluffy aggregates by computing the asymmetry parameter and the cross sections for extinction and scattering. The ballistic particle-cluster aggregate and the ballistic cluster-cluster aggregate consisting of either dielectric or absorbing material are considered to represent naturally existing aggregates. We show that the asymmetry parameter perpendicular to the direction of wave propagation is maximized where the wavelength is comparable to the aggregate size, which may be characterized by the area-equivalent radius or the radius of gyration rather than the volume-equivalent radius. The asymmetry parameter for the aggregate depends on the morphology of the particle, but not on the constituent material. Therefore, the dependence of the radiation pressure cross section on the material composition arises mainly from that of the extinction and scattering cross sections, in other words, the single-scattering albedo. We find that aggregates consisting of high-albedo material show a large deviation of radiation pressure from the direction of incident radiation. When the aggregates are illuminated by blackbody radiation, the deviation of the radiation pressure increases with increasing temperature of the blackbody. Since the parallel component of the radiation pressure cross section for the aggregates is smaller than that for the volume-equivalent spheres at the size parameter close to unity, the Planck-mean radiation pressure cross section for the aggregates having radius comparable to the effective wavelength of radiation shows a lower value, compared with the volume-equivalent sphere. Consequently, the slope of the radiation pressure force per mass of the particle as a function of particle mass shows a lower maximum for the aggregates than for compact spherical particles. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  5. Aggregate size distribution of the soil loss

    Szabó, Judit Alexandra; Jakab, Gergely; Szabó, Boglárka; Józsa, Sándor; Szalai, Zoltán; Centeri, Csaba

    2016-04-01

    In agricultural areas the soil erosion and soil loss estimation is vital information in long-term planning. During the initial period of the erosion a part of the soil particles and aggregates get transportable and nutrients and organic matter could be transported due to the effect of water or wind. This preliminary phase was studied with laboratory-scale rainfall simulator. Developed surface crust and aggregate size composition of the runoff was examined in six different slope-roughness-moisture content combination of a Cambisol and a Regosol. The ratio of micro- and macro aggregates in the runoff indicate the stability of the aggregates and determine the transport capacity of the runoff. Both soil samples were taken from field where the water erosion is a potential hazard. During the experiment the whole amount of runoff and sediment was collected through sieve series to a bucket to separate the micro- and macro aggregates. In case of both samples the micro aggregates dominate in the runoff and the runoff rates are similar. Although the runoff of the Regosol - with dominant >1000μm macro aggregate content - contained almost nothing but ratio 250-1000μm sized macro aggregates. This difference occurred because the samples are resistant against drop erosion differently. In case of both sample the selectivity of the erosion and substance matrix redistribution manifested in mineral crusts in the surface where the quartz deposited in place while the lighter organic matter transported with the sediment. The detachment of the aggregates and the redistribution of the particles highly effect on the aggregate composition of the runoff which is connected with the quality of the soil loss. So while the estimation of soil loss quantity is more or less is easy, measuring aggregate size distribution which is led to nutrient and organic matter redistribution is one of a key questions to improve erosion estimation. G. Jakab was supported by the János Bolyai fellowship of the

  6. RELATIONSHIPS BETWEEN SOIL MICROBIAL BIOMASS, AGGREGATE STABILITY AND AGGREGATE ASSOCIATED-C: A MECHANISTIC APPROACH

    Patrizia Guidi

    2014-01-01

    Full Text Available For the identification of C pools involved in soil aggregation, a physically-based aggregate fractionation was proposed, and  additional pretreatments were used in the measurement of the 1-2 mm aggregate stability in order to elucidate the relevance of the role of soil microorganisms with respect to the different aggregate breakdown mechanisms. The study was carried out on three clay loam Regosols, developed on calcareous shales, known history of organic cultivation.Our results showed that the soil C pool controlling the process of stabilisation of aggregates was related to the microbial community. We identified the resistance to fast wetting as the major mechanism of aggregate stability driven by microorganims. The plausible hypothesis is that organic farming promotes fungi growth, improving water repellency of soil aggregates by fungal hydrophobic substances. By contrast, we failed in the identification of C pools controlling the formation of aggregates, probably because of the disturbance of mechanical tillage which contributes to the breakdown of soil aggregates.The physically-based aggregate fractionation proposed in this study resulted useful in the  mechanistically understanding of the role of microorganisms in soil aggregation and it might be suggested for studying the impact of management on C pools, aggregates properties and their relationships in agricultural soils.

  7. Protein aggregation and lyophilization: Protein structural descriptors as predictors of aggregation propensity

    Roughton, Brock C.; Iyer, Lavanya K.; Bertelsen, Esben; Topp, Elizabeth M.; Camarda, Kyle V.

    2013-01-01

    Lyophilization can induce aggregation in therapeutic proteins, but the relative importance of protein structure, formulation and processing conditions are poorly understood. To evaluate the contribution of protein structure to lyophilization-induced aggregation, fifteen proteins were co-lyophilized with each of five excipients. Extent of aggregation following lyophilization, measured using size-exclusion chromatography, was correlated with computational and biophysical protein structural desc...

  8. 24 CFR 50.21 - Aggregation.

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Aggregation. 50.21 Section 50.21 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development... Aggregation. Activities which are geographically related and are logical parts of a composite of...

  9. 42 CFR 411.106 - Aggregation rules.

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Aggregation rules. 411.106 Section 411.106 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM... Under Group Health Plans: General Provisions § 411.106 Aggregation rules. The following rules apply...

  10. 24 CFR 58.32 - Project aggregation.

    2010-04-01

    ... other activities and actions. (See 40 CFR 1508.25(a)). (2) Consider reasonable alternative courses of... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Project aggregation. 58.32 Section... Environmental Review Process: Documentation, Range of Activities, Project Aggregation and Classification §...

  11. 24 CFR 55.24 - Aggregation.

    2010-04-01

    ... 24 CFR part 58), individual or aggregated approvals may be issued. A single compliance review and... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Aggregation. 55.24 Section 55.24... FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain Management § 55.24...

  12. Choosing Aggregation Rules for Composite Indicators

    Munda, Giuseppe

    2012-01-01

    From a formal point of view, a composite indicator is an aggregate of all dimensions, objectives, individual indicators and variables used for its construction. This implies that what defines a composite indicator is the set of properties underlying its mathematical aggregation convention. In this article, I try to revise the theoretical debate on…

  13. Morphology and mobility of synthetic colloidal aggregates.

    Melas, Anastasios D; Isella, Lorenzo; Konstandopoulos, Athanasios G; Drossinos, Yannis

    2014-03-01

    The relationship between geometric and dynamic properties of fractal-like aggregates is studied in the continuum mass and momentum-transfer regimes. The synthetic aggregates were generated by a cluster-cluster aggregation algorithm. The analysis of their morphological features suggests that the fractal dimension is a descriptor of a cluster's large-scale structure, whereas the fractal prefactor is a local-structure indicator. For a constant fractal dimension, the prefactor becomes also an indicator of a cluster's shape anisotropy. The hydrodynamic radius of orientationally averaged aggregates was calculated via molecule-aggregate collision rates determined from the solution of a Laplace equation. An empirical expression that relates the aggregate hydrodynamic radius to its radius of gyration and the number of primary particles is proposed. The suggested expression depends only on geometrical quantities, being independent of statistical (ensemble-averaged) properties like the fractal dimension and prefactor. Hydrodynamic radius predictions for a variety of fractal-like aggregates are in very good agreement with predictions of other methods and literature values. Aggregate dynamic shape factors and DLCA individual monomer hydrodynamic shielding factors are also calculated. PMID:24407656

  14. Streaming instability of aggregating slime mold amoebae

    Levine, Herbert; Reynolds, William

    1991-05-01

    We propose a new model of aggregation in the cellular slime mold D. Discoideum. Our approach couples the excitable signaling system to amoeba chemotaxis; the resultant system of equations is tractable to analytical and numerical approaches. Using our model, we derive the existence of a streaming instability for the concentric target aggregation pattern.

  15. Teaching Aggregate Demand and Supply Models

    Wells, Graeme

    2010-01-01

    The author analyzes the inflation-targeting model that underlies recent textbook expositions of the aggregate demand-aggregate supply approach used in introductory courses in macroeconomics. He shows how numerical simulations of a model with inflation inertia can be used as a tool to help students understand adjustments in response to demand and…

  16. Teaching Aggregate Demand and Supply Models

    Wells, Graeme

    2007-01-01

    This note analyses the inflation-targeting model that underlies recent textbook expositions of the Aggregate Demand-Aggregate Supply approach used in introductory courses in macroeconomics. The paper shows how numerical simulations of a model with inflation inertia can be used as a tool to help students understand adjustments in response to demand and supply shocks of various kinds.

  17. The impossibility of unbiased judgment aggregation

    Dietrich, Franz; List, Christian

    2010-01-01

    Standard impossibility theorems on judgment aggregation over logically connected propositions either use a controversial systematicity condition or apply only to agendas of propositions with rich logical connections. Are there any serious impossibilities without these restrictions? We prove an impossibility theorem without requiring systematicity that applies to most standard agendas: Every judgment aggregation function (with rational inputs and outputs) satisfying a condition called unbiased...

  18. Protein aggregation in amyotrophic lateral sclerosis

    Blokhuis, Anna M.; Groen, Ewout J. N.; Koppers, Max; van den Berg, Leonard H.; Pasterkamp, R. Jeroen

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the aggregation of ubiquitinated proteins in affected motor neurons. Recent studies have identified several new molecular constituents of ALS-linked cellular aggregates, including FUS, TDP-43, OPTN, UBQLN2 and the tr

  19. Spontaneous intravascular platelet aggregation in angiographic studies

    The process of intravascular platelet aggregation is activated in angiographic clinical studies using 76% Verografin solution. It has been shown in experiments op rats that verografin (2 ml/kg) and iodamide (2 ml/ kg) together with the activation of intravascular platelet aggregation inhibit antiaggregation properties of the vascular wall

  20. Familial Aggregation and Childhood Blood Pressure

    Wang, Xiaoling; Xu, Xiaojing; Su, Shaoyong; Snieder, Harold

    2015-01-01

    There is growing concern about elevated blood pressure (BP) in children. The evidence for familial aggregation of childhood BP is substantial. Twin studies have shown that a large part of the familial aggregation of childhood BP is due to genes. The first part of this review provides the latest prog

  1. Oxidation, aggregation and immunogenicity of therapeutic proteins

    Torosantucci, Riccardo

    2013-01-01

    The aim of the research described in this thesis is to study the chemical mechanisms responsible for protein aggregation induced by metal catalyzed oxidation and to investigate the relationship between protein oxidation, aggregation and immunogenicity. To this end, recombinant human insulin rhIFNβ-1

  2. Dynamic Approaches to In-Network Aggregation

    Kennedy, Oliver; Demers, Al

    2008-01-01

    Collaboration between small-scale wireless devices hinges on their ability to infer properties shared across multiple nearby nodes. Wireless-enabled mobile devices in particular create a highly dynamic environment not conducive to distributed reasoning about such global properties. This paper addresses a specific instance of this problem: distributed aggregation. We present extensions to existing unstructured aggregation protocols that enable estimation of count, sum, and average aggregates in highly dynamic environments. With the modified protocols, devices with only limited connectivity can maintain estimates of the aggregate, despite \\textit{unexpected} peer departures and arrivals. Our analysis of these aggregate maintenance extensions demonstrates their effectiveness in unstructured environments despite high levels of node mobility.

  3. Aggregation of Composite Solutions: strategies, models, examples

    Levin, Mark Sh

    2011-01-01

    The paper addresses aggregation issues for composite (modular) solutions. A systemic view point is suggested for various aggregation problems. Several solution structures are considered: sets, set morphologies, trees, etc. Mainly, the aggregation approach is targeted to set morphologies. The aggregation problems are based on basic structures as substructure, superstructure, median/consensus, and extended median/consensus. In the last case, preliminary structure is built (e.g., substructure, median/consensus) and addition of solution elements is considered while taking into account profit of the additional elements and total resource constraint. Four aggregation strategies are examined: (i) extension strategy (designing a substructure of initial solutions as "system kernel" and extension of the substructure by additional elements); (ii) compression strategy (designing a superstructure of initial solutions and deletion of some its elements); (iii) combined strategy; and (iv) new design strategy to build a new s...

  4. Competitive aggregation dynamics using phase wave signals.

    Sakaguchi, Hidetsugu; Maeyama, Satomi

    2014-10-21

    Coupled equations of the phase equation and the equation of cell concentration n are proposed for competitive aggregation dynamics of slime mold in two dimensions. Phase waves are used as tactic signals of aggregation in this model. Several aggregation clusters are formed initially, and target patterns appear around the localized aggregation clusters. Owing to the competition among target patterns, the number of the localized aggregation clusters decreases, and finally one dominant localized pattern survives. If the phase equation is replaced with the complex Ginzburg-Landau equation, several spiral patterns appear, and n is localized near the center of the spiral patterns. After the competition among spiral patterns, one dominant spiral survives. PMID:24956327

  5. Ratio-Based Gradual Aggregation of Data

    Iftikhar, Nadeem

    2012-01-01

    cause data management and data storage issues. However, non-flexible and ineffective means of data aggregation not only reduce performance of database queries but also lead to erroneous reporting. This paper presents flexible and effective ratio-based methods for gradual data aggregation in databases....... Gradual data aggregation is a process that reduces data volume by converting the detailed data into multiple levels of summarized data as the data gets older. This paper also describes implementation strategies of the proposed methods based on standard database technology.......Majority of databases contain large amounts of data, gathered over long intervals of time. In most cases, the data is aggregated so that it can be used for analysis and reporting purposes. The other reason of data aggregation is to reduce data volume in order to avoid over-sized databases that may...

  6. Excited-state dynamics of astaxanthin aggregates

    Fuciman, Marcel; Durchan, Milan; Šlouf, Václav; Keşan, Gürkan; Polívka, Tomáš

    2013-05-01

    Astaxanthin forms three types of aggregates in hydrated dimethyl sulfoxide (DMSO). In DMSO/water ratio of 1:1, a red-shifted J-aggregate with maximum at 570 nm is generated, while a ratio of 1:9 produces blue-shifted H-aggregates with peaks at 386 nm (H1) and 460 nm (H2). Monomeric astaxanthin in DMSO has an S1 lifetime of 5.3 ps, but a long-lived (33 ps) S∗ signal was also identified. Aggregation changes the S1 lifetimes to 17 ps (H1), 30 ps (H2), and 14 ps (J). Triplet state of astaxanthin, most likely generated via singlet homofission, was observed in H1 and H2 aggregates.

  7. An exact approach for aggregated formulations

    Gamst, Mette; Spoorendonk, Simon

    to mathematical formulations with a different solution space than that for the original formulation, i.e., the aggregated formulation may be a relaxation of the original problem. In a branch-and-bound context, variable aggregation can also lead to a formulation where branching is not trivial, for...... of the original and aggregated formulations. Put in a branch-and-bound context, branching can be performed on the original variables to ensure optimality. We show how to apply the method on well-known optimization problems.......Aggregating formulations is a powerful trick for transforming problems into taking more tractable forms. An example is Dantzig-Wolfe decomposition, which shows superior performance across many applications especially when part of a branch-and-price algorithm. Variable aggregation, however, may lead...

  8. Compressive Strength of Concrete Using Recycled Concrete Aggregate as Complete Replacement of Natural Aggregate

    Osei, Daniel Yaw

    2013-01-01

    This paper presents a report of an experimental investigation on the effect of complete replacement of natural aggregate by recycled concrete aggregate in the production of concrete on the compressive strength of concrete. Two sets of concrete mixtures of ratios 1:3:6, 1:2:4, 1:11/2:3, 1:1:2 by mass were cast using natural aggregates and recycled aggregates concrete respectively. The 28-day compressive strengths of 1:3:6, 1:2:4, 1:11/2:3, 1:1:2 concrete using recycled concrete aggregates were...

  9. Uncovering the Mechanism of Aggregation of Human Transthyretin*

    Saelices, Lorena; Johnson, Lisa M.; Liang, Wilson Y.; Sawaya, Michael R.; Cascio, Duilio; Ruchala, Piotr; Whitelegge, Julian; Jiang, Lin; Riek, Roland; Eisenberg, David S.

    2015-01-01

    Background: Transthyretin (TTR) aggregation is associated with systemic amyloidosis. Results: Residue replacements on the F and H strands hinder TTR aggregation. Conclusion: The F and H strands are aggregation-driving segments of TTR. The binding of designed peptides inhibits protein aggregation. Significance: We point the way to new therapeutic approaches against TTR aggregation by using peptides to block amyloid segments.

  10. Pore Structure of Natural and Regenerated Soil Aggregates

    Naveed, Muhammad; de Jonge, Lis Wollesen; Arthur, Emmanuel;

    2014-01-01

    the soil type and organic matter amendment, and was vastly different from the state of natural aggregates. Aggregate porosity (> 30 Hm) was observed to be a good predictor for the mechanical properties of aggregates. In general, natural aggregates were stronger than lysimeter aggregates....

  11. Familial aggregation of bladder cancer

    Ilić Milena

    2011-01-01

    Full Text Available Background. Except for smoking and certain occupational exposures, the etiology of bladder cancer is largely unknown. Several case reports have described familial aggregation of transitional cell carcinoma of the bladder. Although the majority of patients with bladder cancer do not have family history of transitional cell carcinoma of the urinary tract, the study of familial transitional cell carcinoma may lead to the knowledge on the pathogenesis of this disease. The purpose of this study was to describe three cases of urinary bladder cancer in a single three-member family, i.e. in two generations (mother and son and a family member related by marriage (the patient’s wife. Case report. Three cases of urinary bladder cancer occurred in a three-member family within the interval of 5 years. The following common characteristics were detected in our patients: old age (over 60, working as farmers for more than 50 years, negative personal medical history on relevant health disorders, place of birth - village, place of residence - village, the same water supply, similar nutrition, positive family history on urinary bladder cancer or other malignant tumors, the first sign of illness was macroscopic hematuria in all the patients and the same pathohistological type of cancer - carcinoma papillare transitiocellulare. Conclusion. The stated common characteristics in our cases indicate, above all, the impact of exposure to external surrounding factors on the occurrence of urinary bladder cancer.

  12. The fractal aggregation of asphaltenes.

    Hoepfner, Michael P; Fávero, Cláudio Vilas Bôas; Haji-Akbari, Nasim; Fogler, H Scott

    2013-07-16

    This paper discusses time-resolved small-angle neutron scattering results that were used to investigate asphaltene structure and stability with and without a precipitant added in both crude oil and model oil. A novel approach was used to isolate the scattering from asphaltenes that are insoluble and in the process of aggregating from those that are soluble. It was found that both soluble and insoluble asphaltenes form fractal clusters in crude oil and the fractal dimension of the insoluble asphaltene clusters is higher than that of the soluble clusters. Adding heptane also increases the size of soluble asphaltene clusters without modifying the fractal dimension. Understanding the process of insoluble asphaltenes forming fractals with higher fractal dimensions will potentially reveal the microscopic asphaltene destabilization mechanism (i.e., how a precipitant modifies asphaltene-asphaltene interactions). It was concluded that because of the polydisperse nature of asphaltenes, no well-defined asphaltene phase stability envelope exists and small amounts of asphaltenes precipitated even at dilute precipitant concentrations. Asphaltenes that are stable in a crude oil-precipitant mixture are dispersed on the nanometer length scale. An asphaltene precipitation mechanism is proposed that is consistent with the experimental findings. Additionally, it was found that the heptane-insoluble asphaltene fraction is the dominant source of small-angle scattering in crude oil and the previously unobtainable asphaltene solubility at low heptane concentrations was measured. PMID:23808932

  13. Anisotropic diffusion-limited aggregation.

    Popescu, M N; Hentschel, H G E; Family, F

    2004-06-01

    Using stochastic conformal mappings, we study the effects of anisotropic perturbations on diffusion-limited aggregation (DLA) in two dimensions. The harmonic measure of the growth probability for DLA can be conformally mapped onto a constant measure on a unit circle. Here we map m preferred directions for growth to a distribution on the unit circle, which is a periodic function with m peaks in [-pi,pi) such that the angular width sigma of the peak defines the "strength" of anisotropy kappa= sigma(-1) along any of the m chosen directions. The two parameters (m,kappa) map out a parameter space of perturbations that allows a continuous transition from DLA (for small enough kappa ) to m needlelike fingers as kappa--> infinity. We show that at fixed m the effective fractal dimension of the clusters D(m,kappa) obtained from mass-radius scaling decreases with increasing kappa from D(DLA) approximately 1.71 to a value bounded from below by D(min) = 3 / 2. Scaling arguments suggest a specific form for the dependence of the fractal dimension D(m,kappa) on kappa for large kappa which compares favorably with numerical results. PMID:15244564

  14. Experimental Study on Minimum Ignition Temperature of Bituminous Coal Dust Cloud%烟煤煤尘云最低着火温度实验研究

    邓军; 屈姣; 王秋红; 谢长春

    2014-01-01

    In this PaPer,study and measurement were carried out on the minimum ignition temPerature of three kinds of bituminous coal dust clouds by using the Godbert-Greenwald heating furnace,including the non-caking coal taken from Dafusi Mine in Binxian County,the gas coal from Kouzi East Mine in Anhui Province and the lean coal from 301 working face of Tianchi Mine in Shanxi Province. It was found out from the exPerimental results that the ash content of the gas coal,non-caking coal and lean coal increased in turn,their volatile content reduced in turn,their fixed carbon content increased in turn,and the water content of the lean coal,gas coal and non-caking coal increased in turn;the minimum ignition temPerature of the three kinds of bituminous coal dust clouds decreased with the reduction of their Particle sizes;based on their minimum ignition temPeratures,it was found out that the hardest ignited coal dust was the lean coal and the easiest ignited coal dust was gas coal. This study can Provide an exPerimental basic for the safe Production in coal mines.%为了研究彬县大佛寺矿不粘煤、安徽口孜东矿气煤、山西天池矿301工作面瘦煤等3种烟煤的煤尘云最低着火温度,实验采用Godbert-Greenwald加热炉对以上3种烟煤的煤尘云最低着火温度进行了测试。研究发现气煤、不粘煤、瘦煤的灰分依次增大,挥发分依次减小,固定碳依次增大,水分随瘦煤、气煤、不粘煤依次增大;这3种烟煤煤尘云的最低着火温度都随煤尘粒径的减小而降低;根据最低着火温度,得知煤尘云被引燃的难易程度依次为瘦煤、不粘煤、气煤。此基础研究可为煤矿的安全生产提供实验依据。

  15. 浅谈如何提高Superpave沥青混合料矿料间隙率%Discussion on the improvement of Superpave precent vodis in mineral aggregate in bituminous mixtures

    卢文锋; 杨爱民

    2010-01-01

    针对Superpave沥青混合料设计中经常会遇到VMA较低以及VMA对级配变化不敏感情况,从级配、表面结构、颗粒形状三方面入手,探讨了如何提高Superpave沥青混合料矿料间隙率,以期指导实践.

  16. Thermo-mechanical behavior of bituminous mixtures at low temperatures. Links between the binder characteristics and the mix properties; Comportement thermomecanique des enrobes bitumeux a basses temperatures: relations entre les proprietes du liant et de l'enrobe

    Olard, F.

    2003-10-01

    This thesis has been realized within the framework of a partnership between the Ecole Nationale des TPE, APPIA and EUROVIA. The company Total has also been associated to this project. The study deals with the thermo-mechanical behavior of bituminous materials at low temperatures. The aim is to establish the links between the characteristics of the binder and the properties of bituminous mixes at low temperatures, and to better understand the existing low-temperature parameters and criteria for binders (or to propose new ones), related to the in-situ behavior of bituminous mixtures. A large experimental campaign has been carried out so as to fulfill this goal. After a bibliographical study on the rheology and the thermo-mechanical properties of (pure or modified) binders, putties and mixes, the experimental campaign carried out both in the small strain domain and in the large strain domain, is presented. The low temperature behavior of binders has been evaluated with three common fundamental tests: i)the complex modulus determination, ii)the Bending Beam Rheometer and iii)the tensile strength at a constant strain rate and constant temperatures. A new three point bending test on pre-notched bitumen beams has also been developed at the ENTPE. The low-temperature fracture properties of bitumens were studied at constant temperatures and cross-head speeds considering the Linear Elastic Fracture Mechanics (LEFM) assumptions. The thermo-mechanical behavior of bituminous mixtures has been studied by performing i)complex modulus tests, ii)measurements of the coefficient of thermal dilatation and contraction, iii)tensile tests at constant temperatures and strain rates, and iv)Thermal Stress Restrained Specimen Tests. Apart from the determination of some pertinent links between binder and mix properties and discriminating characteristics with regard to the thermal cracking of bituminous mixes at low temperatures, the analysis has also consisted in modeling the behavior of

  17. Local aggregation characteristics of microscale blood flows

    Kaliviotis, Efstathios; Sherwood, Joseph M.; Dusting, Jonathan; Balabani, Stavroula

    2015-11-01

    Erythrocyte aggregation (EA) is an important aspect of microvascular flows affecting blood flow and viscosity. Microscale blood flows have been studied extensively in recent years using computational and microfluidic based approaches. However, the relationship between the local structural characteristics of blood and the velocity field has not been quantified. We report simultaneous measurements of the local velocity, aggregation and haematocrit distributions of human erythrocytes flowing in a microchannel. EA was induced using Dextran and flows were imaged using brightfield microscopy. Local aggregation characteristics were investigated using statistical and edge-detection image processing techniques while velocity profiles were obtained using PIV algorithms. Aggregation intensity was found to strongly correlate with local variations in velocity in both the central and wall regions of the channel. The edge detection method showed that near the side wall large aggregates are associated with high local velocities and low local shear rates. In the central region large aggregates occurred in regions of low velocity and high erythrocyte concentration. The results demonstrate the combined effect of haematocrit and velocity distributions on local aggregation characteristics.

  18. Lightweight alumina refractory aggregate. Final report

    Swansiger, T.G.; Pearson, A.

    1996-07-16

    Objective was to develop a lightweight, high alumina refractory aggregate for use in various high performance insulating (low thermal conductivity) refractory applications (e.g., in the aluminium, glass, cement, and iron and steel industries). A new aggregate process was developed through bench and pilot-scale experiments involving extrusion of a blend of calcined and activated alumina powders and organic extrusion aids and binders. The aggregate, with a bulk density approaching 2.5 g/cc, exhibited reduced thermal conductivity and adequate fired strength compared to dense tabular aggregate. Refractory manufacturers were moderately enthusiastic over the results. Alcoa prepared an economic analysis for producing lightweight aggregate, based on a retrofit of this process into existing Alcoa production facilities. However, a new, competing lightweight aggregate material was developed by another company; this material (Plasmal{trademark})had a significantly more favorable cost base than the Alcoa/DOE material, due to cheap raw materials and fewer processing steps. In late 1995, Alcoa became a distributor of Plasmal. Alcoa estimated that {ge}75% of the market originally envisioned for the Alcoa/DOE aggregate would be taken by Plasmal. Hence, it was decided to terminate the contract without the full- scale demonstration.

  19. Study of the contribution from gamma dose rate and radon concentration in civilian housing caused by the use of construction material having processing residues from uranium containing bituminous coal in Freital, Saxony

    The past, widerspread use of residues from processing uranium containing bituminous coal in the former mining region of Freital, Saxony, for construction led to increased concentrations of natural radionuclides in the building material of civilian housing. Measurement of the local dose levels in such housing, analytical characterization of the building material, and model calculations allow for the assessment of the contribution of the material to the total radioactive exposure of residents. (orig.)

  20. Aggregation of ice crystals in cirrus

    Kajikawa, Masahiro; Heymsfield, Andrew J.

    1989-01-01

    Results are given from analysis of the aggregation of thick plate, columnar, and bullet rosette ice crystals in cirrus. Data were obtained from PMS 2D-C images, oil coated slides, and aircraft meteorological measurements. Crystal size ranged from 100 to 900 microns in temperatures from -30 to -45 C. The results indicate that the ratio of the sizes of aggregating crystals and the difference of their terminal velocities are important in aggregation. The collection efficiency was calculated for the thick plate crystals from the same data.

  1. Antiplatelet aggregation principles from Ephemerantha lonchophylla.

    Chen, C C; Huang, Y L; Teng, C M

    2000-05-01

    Bioactivity-directed separation led to the identification of four compounds, viz. denbinobin (1), 3,7-dihydroxy-2,4-dimethoxyphenanthrene (2), 3-methylgigantol (3), and erianthridin (4) from the ethanolic extract of Ephemerantha lonchophylla. Antiplatelet tests were carried out using 4 different aggregation inducers, viz. arachidonic acid (AA), thrombin, collagen and platelet activating factor (PAF). The results indicated that only compounds 2, 3, and 4 exhibited generally significant anti-aggregation activities with that against AA-induced aggregation being most effective. Estimated IC50, values in this regard for 2, 3, and 4 were 24 microM, 30 microM and 9 microM, respectively. PMID:10865460

  2. Aggregation and fibrillation of bovine serum albumin

    Holm, NK; Jespersen, SK; Thomassen, LV;

    2007-01-01

    The all-alpha helix multi-domain protein bovine serum albumin (BSA) aggregates at elevated temperatures. Here we show that these thermal aggregates have amyloid properties. They bind the fibril-specific dyes Thioflavin T and Congo Red, show elongated although somewhat worm-like morphology and...... characteristic amyloid X-ray fiber diffraction peaks. Fibrillation occurs over minutes to hours without a lag phase, is independent of seeding and shows only moderate concentration dependence, suggesting intramolecular aggregation nuclei. Nevertheless, multi-exponential increases in dye-binding signal and...

  3. Internal water curing with Liapor aggregates

    Lura, Pietro

    2005-01-01

    Internal water curing is a very efficient way to counteract self-desiccation and autogenous shrinkage in high performance concrete, thereby reducing the likelihood of early-age cracking. This paper deals with early-age volume changes and moisture transport in lightweight aggregate concrete realized......, elastic modulus and compressive strength were measured. Early-age expansion of the mixtures was greater the higher the degree of the saturation of the lightweight aggregates and the finer their particle size. The elastic properties and the earlyage expansion of the lightweight aggregate concrete were...

  4. Exciton dynamics in perturbed vibronic molecular aggregates.

    Brüning, C; Wehner, J; Hausner, J; Wenzel, M; Engel, V

    2016-07-01

    A site specific perturbation of a photo-excited molecular aggregate can lead to a localization of excitonic energy. We investigate this localization dynamics for laser-prepared excited states. Changing the parameters of the electric field significantly influences the exciton localization which offers the possibility for a selective control of this process. This is demonstrated for aggregates possessing a single vibrational degree of freedom per monomer unit. It is shown that the effects identified for the molecular dimer can be generalized to larger aggregates with a high density of vibronic states. PMID:26798840

  5. A look at construction aggregates production

    Willett, Jason Christopher

    2009-01-01

    Construction aggregates are defined as the combination of crushed stone and construction sand and gravel. Aggregates are one of the most accessible natural resources on Earth and one of the fundamental building blocks of our society. They have been used from the earliest times of our civilization for a variety of applications that have increased in number and complexity with time and technological progress. Despite the relatively low but increasing unit value of its basic products, the construction aggregates industry is a major contributor to and an indicator of the economic well-being of the nation.

  6. Aggregate Formed by a Cationic Fluorescence Probe

    TIAN, Juan; SANG, Da-Yong; JI, Guo-Zhen

    2007-01-01

    The aggregation behavior of a cationic fluorescence probe 10-(4,7,10,13,16-pentaoxa-1-azacyclooctadecyl-methyl)anthracen-9-ylmethyl dodecanoate (1) was observed and studied by a fluorescence methodology in acidic and neutral conditions. By using the Py scale, differences between simple aggregates and micelles have been discussed. The stability of simple aggregates was discussed in terms of hydrophobic interaction and electrostatic repulsion. The absence of excimer emission of the anthrancene moiety of probe 1 in neutral condition was attributed to the photoinduced electron transfer mechanism instead of photodimerization.

  7. Programming spiders, bots, and aggregators in Java

    Heaton, Jeff

    2006-01-01

    The content and services available on the web continue to be accessed mostly through direct human control. But this is changing. Increasingly, users rely on automated agents that save them time and effort by programmatically retrieving content, performing complex interactions, and aggregating data from diverse sources. Programming Spiders, Bots, and Aggregators in Java teaches you how to build and deploy a wide variety of these agents-from single-purpose bots to exploratory spiders to aggregators that present a unified view of information from multiple user accounts. You will quickly build on

  8. Fractal aggregation of DNA after thermal denaturation

    Yan Lifeng; Iwasaki, Hiroshi E-mail: iwasaki@sanken.osaka-u.ac.jp

    2004-05-01

    DNA thermal denaturation was observed by atomic force microscopy (AFM) on the surface of newly cleaved mica. It was found that at temperatures higher than the melting point, denaturation of DNA molecules took place and globular particles with size distribution were formed, and these particles could aggregate together to form fractal structures, which followed the diffusion limited aggregation (DLA) model. At 100 deg. C, degradation of DNA took place and small particles of about 20 nm in size were formed, and they also aggregated in fractal structures with a lower dimension. Evaporating speed of water affects the fractal dimension.

  9. Reusing recycled aggregates in structural concrete

    Kou, Shicong

    The utilization of recycled aggregates in concrete can minimize environmental impact and reduce the consumption of natural resources in concrete applications. The aim of this thesis is to provide a scientific basis for the possible use of recycled aggregates in structure concrete by conducting a comprehensive programme of laboratory study to gain a better understanding of the mechanical, microstructure and durability properties of concrete produced with recycled aggregates. The study also explored possible techniques to of improve the properties of recycled aggregate concrete that is produced with high percentages (≧ 50%) of recycled aggregates. These techniques included: (a) using lower water-to-cement ratios in the concrete mix design; (b) using fly ash as a cement replacement or as an additional mineral admixture in the concrete mixes, and (c) precasting recycled aggregate concrete with steam curing regimes. The characteristics of the recycled aggregates produced both from laboratory and a commercially operated pilot construction and demolition (C&D) waste recycling plant were first studied. A mix proportioning procedure was then established to produce six series of concrete mixtures using different percentages of recycled coarse aggregates with and without the use of fly ash. The water-to-cement (binder) ratios of 0.55, 0.50, 0.45 and 0.40 were used. The fresh properties (including slump and bleeding) of recycled aggregate concrete (RAC) were then quantified. The effects of fly ash on the fresh and hardened properties of RAC were then studied and compared with those RAC prepared with no fly ash addition. Furthermore, the effects of steam curing on the hardened properties of RAC were investigated. For micro-structural properties, the interfacial transition zones of the aggregates and the mortar/cement paste were analyzed by SEM and EDX-mapping. Moreover, a detailed set of results on the fracture properties for RAC were obtained. Based on the experimental

  10. Secure Data Aggregation in Wireless Sensor Networks

    Dr. Debmalya Bhattacharya

    2014-04-01

    Full Text Available The Security in sensor networks has become most important aspect along with low power as the sensors are unattended so there is more possibility of attack in WSN than usual networks, data aggregation security is an important task as if some false node injects a highly odd value it will affect the whole aggregation process, The paper reviews the need of security for data aggregation and propose an architecture which can eliminate the false values injection as well as provides end to end reliability and data freshness, the architecture is also energy optimized.

  11. Ratio-Based Gradual Aggregation of Data

    Iftikhar, Nadeem

    2012-01-01

    Majority of databases contain large amounts of data, gathered over long intervals of time. In most cases, the data is aggregated so that it can be used for analysis and reporting purposes. The other reason of data aggregation is to reduce data volume in order to avoid over-sized databases that may....... Gradual data aggregation is a process that reduces data volume by converting the detailed data into multiple levels of summarized data as the data gets older. This paper also describes implementation strategies of the proposed methods based on standard database technology....

  12. Acid Resistance of Concrete Containing Laterite Aggregate as Partial Coarse Aggregate Replacement

    K. Muthusamy

    2014-05-01

    Full Text Available In Malaysia, issues of granite aggregate depletion in future due to increasing use in concrete industry and the availability of laterite aggregate locally has initiated studies on concrete produced using laterite aggregate as partial coarse aggregate replacement. Although, replacement of laterite aggregate up to 30% able to produce concrete with the targeted strength but durability of this concrete towards acid attack yet to be investigated. Thus, this study presents and discusses the performance of concrete consisting various percentage of laterite aggregate integrated as partial coarse aggregate replacement upon exposure to acidic environment. Mixes consisting various content of laterite aggregate as partial coarse aggregate replacement ranging from 0, 10, 20, 30, 40 and 50%, respectively were prepared in form of cubes and then subjected to water curing for 28 days before immersed in hydrochloric acid solution for 1800 h. Performance of the specimens were observed through mass loss and strength reduction. Generally, durability performance of concrete produced using up to 20% of laterite aggregate is comparable to plain concrete.

  13. Metal concentrations in aggregate interiors, exteriors, whole aggregates, and bulk of Costa Rican soils

    Wilcke, W.; Kretzschmar, S.; Bundt, M.; Zech, W.

    1999-10-01

    In many temperate soils the preferential weathering and leaching of aggregate surfaces and the nonaggregated material between aggregates depletes geogenic metals. It also shifts metals from strongly to more weakly bound metal forms. Deposited metals are sorbed preferentially on aggregate surfaces and between aggregates. The authors examined whether preferential desilication under tropical climate causes an enrichment in the aggregate exteriors in oxidic forms of metals. They also studied where deposited metals are bound in these soils. Aggregates (2--20 mm) were selected manually from the A horizons of eight Oxisols, six Andisols, two Mollisols, and two Inceptisols in Costa Rica. All samples were fractionated into interior and exterior portions and treated with a seven-step sequence to extract Al, Cd, Cu, Fe, Mn, Pb, and Zn. Total concentrations of all metals except Zn were higher in the aggregate exteriors than in the interiors. The average Cd and Pb concentrations in easily extractable fractions were significantly higher in the aggregate exteriors. There were no significant differences in metal partitioning between interiors and exteriors except for Pb, which had higher proportions in extractable forms with NH{sub 2}OH {center{underscore}dot} HCl {gt} NH{sub 4} - acetate, pH 6.0 {gt} EDTA in the exteriors. There were few significant differences in metal concentrations and partitioning between bulk soil and whole aggregates. The results may be explained by (i) preferential desilication of the aggregate exteriors and (ii) preferential sorption of deposited heavy metals mainly in easily extractable forms.

  14. The theory of judgment aggregation: an introductory review

    List, Christian

    2010-01-01

    This paper provides an introductory review of the theory of judgment aggregation. It introduces the paradoxes of majority voting that originally motivated the field, explains several key results on the impossibility of propositionwise judgment aggregation, presents a pedagogical proof of one of those results, discusses escape routes from the impossibility and relates judgment aggregation to some other salient aggregation problems, such as preference aggregation, abstract aggregation and proba...

  15. p53 Aggregates penetrate cells and induce the co-aggregation of intracellular p53.

    Karolyn J Forget

    Full Text Available Prion diseases are unique pathologies in which the infectious particles are prions, a protein aggregate. The prion protein has many particular features, such as spontaneous aggregation, conformation transmission to other native PrP proteins and transmission from an individual to another. Protein aggregation is now frequently associated to many human diseases, for example Alzheimer's disease, Parkinson's disease or type 2 diabetes. A few proteins associated to these conformational diseases are part of a new category of proteins, called prionoids: proteins that share some, but not all, of the characteristics associated with prions. The p53 protein, a transcription factor that plays a major role in cancer, has recently been suggested to be a possible prionoid. The protein has been shown to accumulate in multiple cancer cell types, and its aggregation has also been reproduced in vitro by many independent groups. These observations suggest a role for p53 aggregates in cancer development. This study aims to test the «prion-like» features of p53. Our results show in vitro aggregation of the full length and N-terminally truncated protein (p53C, and penetration of these aggregates into cells. According to our findings, the aggregates enter cells using macropinocytosis, a non-specific pathway of entry. Lastly, we also show that once internalized by the cell, p53C aggregates can co-aggregate with endogenous p53 protein. Together, these findings suggest prion-like characteristics for p53 protein, based on the fact that p53 can spontaneously aggregate, these aggregates can penetrate cells and co-aggregate with cellular p53.

  16. Aggregate structure, morphology and the effect of aggregation mechanisms on viscosity at elevated protein concentrations.

    Barnett, Gregory V; Qi, Wei; Amin, Samiul; Neil Lewis, E; Roberts, Christopher J

    2015-12-01

    Non-native aggregation is a common issue in a number of degenerative diseases and during manufacturing of protein-based therapeutics. There is a growing interest to monitor protein stability at intermediate to high protein concentrations, which are required for therapeutic dosing of subcutaneous injections. An understanding of the impact of protein structural changes and interactions on the protein aggregation mechanisms and resulting aggregate size and morphology may lead to improved strategies to reduce aggregation and solution viscosity. This report investigates non-native aggregation of a model protein, α-chymotrypsinogen, under accelerated conditions at elevated protein concentrations. Far-UV circular dichroism and Raman scattering show structural changes during aggregation. Size exclusion chromatography and laser light scattering are used to monitor the progression of aggregate growth and monomer loss. Monomer loss is concomitant with increased β-sheet structures as monomers are added to aggregates, which illustrate a transition from a native monomeric state to an aggregate state. Aggregates grow predominantly through monomer-addition, resulting in a semi-flexible polymer morphology. Analysis of aggregation growth kinetics shows that pH strongly affects the characteristic timescales for nucleation (τn) and growth (τg), while the initial protein concentration has only minor effects on τn or τg. Low-shear viscosity measurements follow a common scaling relationship between average aggregate molecular weight (Mw(agg)) and concentration (σ), which is consistent with semi-dilute polymer-solution theory. The results establish a link between aggregate growth mechanisms, which couple Mw(agg) and σ, to increases in solution viscosity even at these intermediate protein concentrations (less than 3w/v %). PMID:26284891

  17. Development of a method to determine the nuclide inventory in bituminized waste packages; Entwicklung eines Verfahrens zur Bestimmung des Nuklidinventars in bituminierten Abfallgebinden

    Mesalic, E.; Kortman, F.; Lierse von Gostomski, C. [Technische Univ. Muenchen, Garching (Germany). Zentrale Technisch-Wissenschaftliche Betriebseinheit Radiochemie Muenchen (RCM)

    2014-01-15

    Until the 1980s, bitumen was used as a conditioning agent for weak to medium radioactive liquid waste. Its use can be ascribed mainly to the properties that indicated that the matrix was optimal. However, fires broke out repeatedly during the conditioning process, so that the method is meanwhile no longer permitted in Germany. There are an estimated 100 waste packages held by the public authorities in Germany that require a supplementary declaration. In contrast to the common matrices, such as for example resins or sludges, there is still no standardized technology for taking samples and subsequently determining the radio-nuclide for bitumen. Aspects, such as the thermoplastic behaviour, make determining the nuclide inventory more difficult in bituminized waste packages. The development of a standardized technology to take samples with a subsequent determination of the radio-nuclide analysis is the objective of a project funded by the BMBF. Known, new methods, specially developed for the project, are examined on inactive bitumen samples and then transferred to active samples. At first non-destructive methods are used. The resulting information forms an important basis to work out and apply destructive strategy for sampling and analysis. Since the project is on-going, this report can only address the development of the sampling process. By developing a sampling system, it will be possible to take samples from an arbitrary selected location of the package across the entire matrix level and thus gain representative analysis material. The process is currently being optimized. (orig.)

  18. Changes in optical properties, chemistry, and micropore and mesopore characteristics of bituminous coal at the contact with dikes in the Illinois Basin

    Mastalerz, Maria; Drobniak, A.; Schimmelmann, A.

    2009-01-01

    Changes in high-volatile bituminous coal (Pennsylvanian) near contacts with two volcanic intrusions in Illinois were investigated with respect to optical properties, coal chemistry, and coal pore structure. Vitrinite reflectance (Ro) increases from 0.62% to 5.03% within a distance of 5.5??m from the larger dike, and from 0.63% to 3.71% within 3.3??m from the small dike. Elemental chemistry of the coal shows distinct reductions in hydrogen and nitrogen content close to the intrusions. No trend was observed for total sulfur content, but decreases in sulfate content towards the dikes indicate thermochemical sulfate reduction (TSR). Contact-metamorphism has a dramatic effect on coal porosity, and microporosity in particular. Around the large dike, the micropore volume, after a slight initial increase, progressively decreases from 0.0417??cm3/g in coal situated 4.7??m from the intrusive contact to 0.0126??cm3/g at the contact. Strongly decreasing mesopore and micropore volumes in the altered zone, together with frequent cleat and fracture filling by calcite, indicate deteriorating conditions for both coalbed gas sorption and gas transmissibility. ?? 2008 Elsevier B.V. All rights reserved.

  19. Adsorption of bituminous components at oil/water interfaces investigated by quartz crystal microbalance: implications to the stability of water-in-oil emulsions.

    Goual, Lamia; Horváth-Szabó, Géza; Masliyah, Jacob H; Xu, Zhenghe

    2005-08-30

    Silica-gel-coated QCM crystals oscillating in a thickness shear mode are used to measure adsorption of bituminous components in water-saturated heptol (1/1 vol ratio of a heptane/toluene mixture) at the oil/water interface. In addition to the viscoelasticity of the adsorbed film, the effects of the bulk liquid density and viscosity as well as the liquid trapped in interfacial cavities are taken into account for the calculation of adsorbed mass. Asphaltenes in heptol adsorb continuously at the oil/water interface, while resins (the surface-active species in maltenes) show adsorption saturation in the same solvent. For Athabasca bitumen in heptol, two adsorption regimes are observed depending on concentration. At low concentrations, a slow, non-steady-state, and irreversible adsorption takes place. At high concentrations, a steady-state adsorption with limited reversibility results in a quick adsorption saturation. The threshold concentration between these adsorption regimes is 1.5 wt % and 8 wt % for oil/water and oil/gold interfaces, respectively. The threshold concentration, the total adsorbed amount, and the flux of non-steady-state adsorption depend on the resin-to-asphaltene ratio. The threshold concentration is related to the earlier reported critical bitumen concentration characterizing the rigid-to-flexible transition of the interfacial film. We propose a new mechanism based on the change of the effective resin-to-asphaltene ratio with dilution to explain both the adsorption behavior and emulsion stability. PMID:16114932

  20. Control of aggregation-induced emission by DNA hybridization

    Li, Shaoguang; Langenegger, Simon Matthias; Häner, Robert

    2013-01-01

    Aggregation-induced emission (AIE) was studied by hybridization of dialkynyl-tetraphenylethylene (DATPE) modified DNA strands. Molecular aggregation and fluorescence of DATPEs are controlled by duplex formation.

  1. Salt-induced aggregation of stiff polyelectrolytes

    Molecular dynamics simulation techniques are used to study the process of aggregation of highly charged stiff polyelectrolytes due to the presence of multivalent salt. The dominant kinetic mode of aggregation is found to be the case of one end of one polyelectrolyte meeting others at right angles, and the kinetic pathway to bundle formation is found to be similar to that of flocculation dynamics of colloids as described by Smoluchowski. The aggregation process is found to favor the formation of finite bundles of 10-11 filaments at long times. Comparing the distribution of the cluster sizes with the Smoluchowski formula suggests that the energy barrier for the aggregation process is negligible. Also, the formation of long-lived metastable structures with similarities to the raft-like structures of actin filaments is observed within a range of salt concentration.

  2. Silt-clay aggregates on Mars

    Greeley, R.

    1979-01-01

    Viking observations suggest abundant silt and clay particles on Mars. It is proposed that some of these particles agglomerate to form sand size aggregates that are redeposited as sandlike features such as drifts and dunes. Although the binding for the aggregates could include salt cementation or other mechanisms, electrostatic bonding is considered to be a primary force holding the aggregates together. Various laboratory experiments conducted since the 19th century, and as reported here for simulated Martian conditions, show that both the magnitude and sign of electrical charges on windblown particles are functions of particle velocity, shape and composition, atmospheric pressure, atmospheric composition and other factors. Electrical charges have been measured for saltating particles in the wind tunnel and in the field, on the surfaces of sand dunes, and within dust clouds on earth. Similar, and perhaps even greater, charges are proposed to occur on Mars, which could form aggregates of silt and clay size particles

  3. Trade Openness and Aggregate Productive Efficiency

    Georgios E. Chortareas; Evangelia Desli; Theodore Pelagidis

    2003-01-01

    We consider whether openness is related to the aggregate technical efficiency in the OECD countries. We obtain efficiency measures using Data Envelopment Analysis and we find that our measure of openness is positively related to the technical efficiency scores.

  4. Excited-state dynamics of astaxanthin aggregates

    Fuciman, M.; Durchan, Milan; Šlouf, V.; Kesan, G.; Polívka, Tomáš

    2013-01-01

    Roč. 568, č. 1 (2013), s. 21-25. ISSN 0009-2614 Institutional support: RVO:60077344 Keywords : astaxanthin * aggregates * excited states Subject RIV: BO - Biophysics Impact factor: 1.991, year: 2013

  5. Familial aggregation and childhood blood pressure.

    Wang, Xiaoling; Xu, Xiaojing; Su, Shaoyong; Snieder, Harold

    2015-01-01

    There is growing concern about elevated blood pressure (BP) in children. The evidence for familial aggregation of childhood BP is substantial. Twin studies have shown that a large part of the familial aggregation of childhood BP is due to genes. The first part of this review provides the latest progress in gene finding for childhood BP, focusing on the combined effects of multiple loci identified from the genome-wide association studies on adult BP. We further review the evidence on the contribution of the genetic components of other family risk factors to the familial aggregation of childhood BP including obesity, birth weight, sleep quality, sodium intake, parental smoking, and socioeconomic status. At the end, we emphasize the promise of using genomic-relatedness-matrix restricted maximum likelihood (GREML) analysis, a method that uses genome-wide data from unrelated individuals, in answering a number of unsolved questions in the familial aggregation of childhood BP. PMID:25432901

  6. Modeling In-Network Aggregation in VANETs

    Dietzel, Stefan; Kargl, Frank; Heijenk, Geert; Schaub, Florian

    2011-01-01

    The multitude of applications envisioned for vehicular ad hoc networks requires efficient communication and dissemination mechanisms to prevent network congestion. In-network data aggregation promises to reduce bandwidth requirements and enable scalability in large vehicular networks. However, most

  7. Antibiotics promote aggregation within aquatic bacterial communities

    ManuelaCoci

    2014-07-01

    These results represent the first observation of co-aggregation as a successful strategy of AB resistance based on phenotype in aquatic bacterial communities, and can represent a fundamental step in the understanding of the effects of AB.

  8. Genetics Home Reference: tubular aggregate myopathy

    ... M, Laporte J. Constitutive activation of the calcium sensor STIM1 causes tubular-aggregate myopathy. Am J Hum ... personal health condition should consult with a qualified healthcare professional . About Genetics Home Reference Site Map Contact ...

  9. Content aggregation and network architectures Group 3

    CERN. Geneva; Horstmann, Wolfram

    2007-01-01

    This breakout session has a technical-organisational focus and touches upon the following topics: - aggregation: aggregation services can provide added value that goes beyond search; - architectures: networked infrastructures can mediate between service providers and data providers. The session involves major initiatives in the field: OAI-practice as experienced by important service providers and implications for a smooth, machine-based content aggregation will be addressed. The relation of distributed and aggregated content and, respectively, the relation of data-providers and service-providers will be furthered: added values enabled by novel approaches to data re-use such as ORE and infrastructural architectures for inter-repository network-operation such as those coming from the DRIVER-project will be discussed. Participants will be provided time and scope to raise issues, share their experiences and elaborate possible scenarios.

  10. Inverted aggregates of luminescent ruthenium metallosurfactants

    D. Domínguez-Gutiérrez; G. de Paoli; A. Guerrero-Martinez; G. Ginocchietti; D. Ebeling; E. Eiser; L. De Cola; C.J. Elsevier

    2008-01-01

    Metallosurfactants and their resulting aggregates combine unique spectroscopic and reactivity properties due to space confinement. We have found the requirements to obtain the first inverted micelles with luminescent metallosurfactants. The compounds possess several long linear chains that favour th

  11. EFFECT OF AGGREGATION ON VIBRIO CHOLERA INACTIVATION

    Extensive research has shown that microorganisms exhibit increased resistance due to clumping, aggregation, particle association or modification of antecedent growth conditions. uring the course of investigating a major waterborne V. Cholerae outbreak in Peru, U.S. EPA investigat...

  12. Suspensions of colloidal particles and aggregates

    Babick, Frank

    2016-01-01

    This book addresses the properties of particles in colloidal suspensions. It has a focus on particle aggregates and the dependency of their physical behaviour on morphological parameters. For this purpose, relevant theories and methodological tools are reviewed and applied to selected examples. The book is divided into four main chapters. The first of them introduces important measurement techniques for the determination of particle size and interfacial properties in colloidal suspensions. A further chapter is devoted to the physico-chemical properties of colloidal particles—highlighting the interfacial phenomena and the corresponding interactions between particles. The book’s central chapter examines the structure-property relations of colloidal aggregates. This comprises concepts to quantify size and structure of aggregates, models and numerical tools for calculating the (light) scattering and hydrodynamic properties of aggregates, and a discussion on van-der-Waals and double layer interactions between ...

  13. Fish Aggregation Sites in the Florida Keys

    National Oceanic and Atmospheric Administration, Department of Commerce — Spawning aggregations are an important event in the life-history of many coral reef fish species. During short time periods (typically during full moons), fish will...

  14. A Deliberation Procedure for Judgment Aggregation Problems

    Slavkovik, Marija; Jamroga, Wojciech

    2016-01-01

    Judgment aggregation problems are a class of collective decision-making problems represented in an abstract way, subsuming some well known collective decision-making problems such voting problems. A collective decision can be reached either by aggregation of individual decisions or by deliberation -- allowing each decision-maker to change their individual decision in response to the individual decisions the other decision-makers made in the previous step. Impossibility results exist for judgm...

  15. An Analysis of Rank Aggregation Algorithms

    Lv, Gattaca

    2014-01-01

    Rank aggregation is an essential approach for aggregating the preferences of multiple agents. One rule of particular interest is the Kemeny rule, which maximises the number of pairwise agreements between the final ranking and the existing rankings. However, Kemeny rankings are NP-hard to compute. This has resulted in the development of various algorithms. Fortunately, NP-hardness may not reflect the difficulty of solving problems that arise in practice. As a result, we aim to demonstrate that...

  16. Some Properties of concretes containing recycled aggregates

    DJERBI TEGGUER, Assia; SAILLIO, Mickael; MAIH-NHU, Johnathan; SCHMITT, Lucie; ROUGEAU, Patrick

    2015-01-01

    This paper presents the results of an experimental campaign which aimed at determining the viability of incorporating recycled aggregates from concrete, in the production of a new concrete, with acceptable performances for its use in new structures. Nine concrete mixtures with different recycled aggregates contents and with different water to binder (w/b) ratio were studied. The mean compressive strength for the reference concretes is comprised between 30 and 60 MPa. Tests were performed to m...

  17. The materials science of protein aggregation

    Cox, D L; Lashuel, H. A.; Lee, K. Y. C.; Singh, R. R. R.

    2005-01-01

    Numerous human diseases are associated with conformational change and aggregation of proteins, including Alzheimer's, Parkinson's, prion diseases (such as mad cow disease), familial amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), Huntington's, and type II (mature onset) diabetes. In many cases, it has been demonstrated that conformational change and aggregation can occur outside living cells and complex biochemical networks. Hence, approaches from materials and physical science ...

  18. Probability Aggregates in Probability Answer Set Programming

    Saad, Emad

    2013-01-01

    Probability answer set programming is a declarative programming that has been shown effective for representing and reasoning about a variety of probability reasoning tasks. However, the lack of probability aggregates, e.g. {\\em expected values}, in the language of disjunctive hybrid probability logic programs (DHPP) disallows the natural and concise representation of many interesting problems. In this paper, we extend DHPP to allow arbitrary probability aggregates. We introduce two types of p...

  19. Aggregating judgments by the majority method

    García Bermejo, Juan Carlos

    2006-01-01

    “Judgement aggregation has been receiving increasing attention over recent years. Some typical impossibility results have been proved, about majority and other similar aggregation methods. Those results depend essentially on certain logical constraints borrowed from standard two- valued deductive logic. Nevertheless, the adequacy of these constraints is doubtful. In this paper, we show that by weakening the consistency conditions in a plausible way, such impossibility theorems can be reversed...

  20. Aggregate Implications of Micro Asset Market Segmentation

    Chris Edmond; Pierre-Olivier Weill

    2011-01-01

    This paper develops a consumption-based asset pricing model to explain and quantify the aggregate implications of a frictional financial system, comprised of many financial markets partially integrated with one another. Each of our micro financial market's is inhabited by traders who are specialized in that markets type of asset. We specify exogenously the level of segmentation that ultimately determines how much idiosyncratic risk traders bear in their micro market and derive aggregate asset...

  1. HOPE aggregator infrastructure release 2.0

    Bardi, Alessia; Zoppi, Franco

    2012-01-01

    This document describes the implementation of the HOPE Aggregator Infrastructure in terms of: . Core Functionalities . Software Tools for Quality Control and Metadata Enrichment . HW & SW requirements After an introduction to the general characteristics of the HOPE implementation, the functionalities offered by this Release 2.0 are presented. Then, the characteristics of the software tools available for Aggregator Administration and Data Curation are introduced. A further section reports the ...

  2. A Visibility Graph Averaging Aggregation Operator

    Chen, Shiyu; Hu, Yong; Mahadevan, Sankaran; Deng, Yong

    2013-01-01

    The problem of aggregation is considerable importance in many disciplines. In this paper, a new type of operator called visibility graph averaging (VGA) aggregation operator is proposed. This proposed operator is based on the visibility graph which can convert a time series into a graph. The weights are obtained according to the importance of the data in the visibility graph. Finally, the VGA operator is used in the analysis of the TAIEX database to illustrate that it is practical and compare...

  3. Consistent GDP Aggregation and Purchasing Power Parity

    Dumagan, Jesus C.

    2012-01-01

    Consistent aggregation ensures that real GDP level and growth do not change as the existing GDP components are merely rearranged. Otherwise, level or growth changes are spurious. This paper proposes a framework for consistent aggregation where components are converted to "purchasing power parity" (PPP) values that "add up exactly" to the same real GDP regardless of the grouping of components. This PPP framework applies to GDP either in constant prices or in chained prices. PPP is applied to U...

  4. Rheopexy of synovial fluid and protein aggregation

    Oates, Katherine M.N; Krause, Wendy E; Jones, Ronald L; Colby, Ralph H.

    2005-01-01

    Bovine synovial fluid and albumin solutions of similar concentration are rheopectic (stress increases with time in steady shear). This unusual flow characteristic is caused by protein aggregation, and the total stress is enhanced by entanglement of this tenuous protein network with the long-chain polysaccharide sodium hyaluronate under physiological conditions. Neutron scattering measurements on albumin solutions demonstrate protein aggregation and all measurements are consistent with a weak ...

  5. Two Scale Model for Aggregation and Etching

    John, G C; John, George C.; Singh, Vijay A.

    1995-01-01

    We propose a dual scale drift-diffusion model for interfacial growth and etching processes. The two scales are: (i) a depletion layer width surrounding the aggregate and (ii) a drift length.The interplay between these two antithetical scales yields a variety of distinct morphologies reported in electrochemical deposition of metals, viscous fingering in fluids and in porous silicon formation. Further, our algorithm interpolates between existing growth models (diffusion limited aggregation, ballistic deposition and Eden) for limiting values of these variables.

  6. Familial Aggregation and Childhood Blood Pressure

    Wang, Xiaoling; Xu, Xiaojing; Su, Shaoyong; Snieder, Harold

    2015-01-01

    There is growing concern about elevated blood pressure (BP) in children. The evidence for familial aggregation of childhood BP is substantial. Twin studies have shown that a large part of the familial aggregation of childhood BP is due to genes. The first part of this review provides the latest progress in gene finding for childhood BP, focusing on the combined effects of multiple loci identified from the genome-wide association studies on adult BP. We further review the evidence on the contr...

  7. Geopolymerization of lightweight aggregate waste

    Labrincha, J. A.

    2008-09-01

    Full Text Available Geopolymerization is a viable way to process and re-use alumino-silicate industrial waste while producing highstrength, high chemical inertia materials that can effectively immobilize other industrial by-products, and even hazardous waste. In this study industrial waste from different stages of the manufacture of lightweight expanded clay aggregate was characterized for its possible transformation, via alkali activation, to geopolymers. The ultimate aim was to assess the possibility of using such geopolymers to develop thermal and acoustic insulation panels. The containment of hazardous materials is another important application for these new materials. Geopolymers were prepared for this study with different particles size distributions and activator concentrations. Their mechanical properties, composition and microstructure were characterized and a material with promising insulating properties was produced. A preliminary analysis was conducted of the salt formation observed in these geopolymers, the chief drawback to their use.La geopolimerización es una manera viable para procesar y agregar valor a los residuos industriales de alumino-silicato dando lugar a materiales con elevadas resistencias mecánmicas, alta inercia química y que permiten encapsular otros residuos, incluso peligrosos. Los residuos industriales que proceden de diversos tipos de arcillas para la fabricación de áridos ligeros se han caracterizado para la producción de geopolímeros mediante el proceso de ataque alcalino. Su incorporación en una matriz geopolimérica permite la posibilidad de desarrollo de paneles de aislamiento (térmico y acústico. Además, la inmovilización de materiales peligrosos es un logro adicional importante. Los geopolímeros se han producido con fórmulas diferentes y se han caracterizado sus propiedades mecánicas, composición y microestructura, para dar lugar a una composición interesante con propiedades aislantes. Se ha llevado a cabo

  8. Growth hormone aggregates in the rat adenohypophysis

    Farrington, M.; Hymer, W. C.

    1990-01-01

    Although it has been known for some time that GH aggregates are contained within the rat anterior pituitary gland, the role that they might play in pituitary function is unknown. The present study examines this issue using the technique of Western blotting, which permitted visualization of 11 GH variants with apparent mol wt ranging from 14-88K. Electroelution of the higher mol wt variants from gels followed by their chemical reduction with beta-mercaptoethanol increased GH immunoassayability by about 5-fold. With the blot procedure we found 1) that GH aggregates greater than 44K were associated with a 40,000 x g sedimentable fraction; 2) that GH aggregates were not present in glands from thyroidectomized rats, but were in glands from the thyroidectomized rats injected with T4; 3) that GH aggregates were uniquely associated with a heavily granulated somatotroph subpopulation isolated by density gradient centrifugation; and 4) that high mol wt GH forms were released from the dense somatotrophs in culture, since treatment of the culture medium with beta-mercaptoethanol increased GH immunoassayability by about 5-fold. Taken together, the results show that high mol wt GH aggregates are contained in secretory granules of certain somatotrophs and are also released in aggregate form from these cells in vitro.

  9. An Identity Based Aggregate Signature from Pairings

    Yike Yu

    2011-04-01

    Full Text Available An aggregate signature is a useful digital signature that supports aggregation: Given n signatures on n distinct messages from n distinct users, aggregate signature scheme is possible to aggregate all these signature into a single short signature. This single signature, along with the n original messages will convince any verifier that the n users did indeed sign the n original messages respectively (i.e., for i=1,...,n user i signed message  mi. In this paper, we propose an identity based aggregate signature scheme which requires constant pairing operations in the verification and the size of aggregate signature is independent of the number of signers. We prove that the proposed signature scheme is secure against existential forgery under adaptively chosen message and identity attack in the random oracle model assuming the intractability of the computational Diffie-Hellman problem.

  10. Dielectric modelling of erythrocyte aggregation in blood

    The dielectric spectrum of whole blood is markedly changed by aggregation of erythrocytes, the so-called rouleau formation. The dielectric behaviour has been simulated using an erythrocyte model that is a disc covered with a thin membrane and an erythrocyte aggregate model that is a pile of the discs with regular spacing ds. The effective complex permittivity of a cubic system including one of the models was calculated by a numerical technique based on the three-dimensional finite-difference method. Both the models have anisotropic dielectric properties depending on whether the rotational axis of the separate or the aggregate model is parallel (the parallel orientation) or perpendicular (the perpendicular orientation) to the direction of the applied electric field. The models both showed a single dielectric relaxation, which was different in intensity and characteristic frequency between the two orientations. For the erythrocyte aggregate model, the relaxation intensity Δε increased and the characteristic frequency fc decreased with decreasing ds in the perpendicular orientation, whereas the opposite ds-dependence was found for Δε and fc in the parallel orientation. Increasing the number of cells in the aggregate model enhanced these effects. The difference in dielectric spectrum between the separate and the aggregate models represented well the dielectric spectrum change caused by rouleau formation

  11. Particle aggregation mechanisms in ionic liquids.

    Szilagyi, Istvan; Szabo, Tamas; Desert, Anthony; Trefalt, Gregor; Oncsik, Tamas; Borkovec, Michal

    2014-05-28

    Aggregation of sub-micron and nano-sized polystyrene latex particles was studied in room temperature ionic liquids (ILs) and in their water mixtures by time-resolved light scattering. The aggregation rates were found to vary with the IL-to-water molar ratio in a systematic way. At the water side, the aggregation rate is initially small, but increases rapidly with increasing IL content, and reaches a plateau value. This behaviour resembles simple salts, and can be rationalized by the competition of double-layer and van der Waals forces as surmised by the classical theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO). At the IL side, aggregation slows down again. Two generic mechanisms could be identified to be responsible for the stabilization in ILs, namely viscous stabilization and solvation stabilization. Viscous stabilization is important in highly viscous ILs, as it originates from the slowdown of the diffusion controlled aggregation due to the hindrance of the diffusion in a viscous liquid. The solvation stabilization mechanism is system specific, but can lead to a dramatic slowdown of the aggregation rate in ILs. This mechanism is related to repulsive solvation forces that are operational in ILs due to the layering of the ILs close to the surfaces. These two stabilization mechanisms are suspected to be generic, as they both occur in different ILs, and for particles differing in surface functionalities and size. PMID:24727976

  12. Effects of tau domain-specific antibodies and intravenous immunoglobulin on tau aggregation and aggregate degradation.

    Esteves-Villanueva, Jose O; Trzeciakiewicz, Hanna; Loeffler, David A; Martić, Sanela

    2015-01-20

    Tau pathology, including neurofibrillary tangles, develops in Alzheimer's disease (AD). The aggregation and hyperphosphorylation of tau are potential therapeutic targets for AD. Administration of anti-tau antibodies reduces tau pathology in transgenic "tauopathy" mice; however, the optimal tau epitopes and conformations to target are unclear. Also unknown is whether intravenous immunoglobulin (IVIG) products, currently being evaluated in AD trials, exert effects on pathological tau. This study examined the effects of anti-tau antibodies targeting different tau epitopes and the IVIG Gammagard on tau aggregation and preformed tau aggregates. Tau aggregation was assessed by transmission electron microscopy and fluorescence spectroscopy, and the binding affinity of the anti-tau antibodies for tau was evaluated by enzyme-linked immunosorbent assays. Antibodies used were anti-tau 1-150 ("D-8"), anti-tau 259-266 ("Paired-262"), anti-tau 341-360 ("A-10"), and anti-tau 404-441 ("Tau-46"), which bind to tau's N-terminus, microtubule binding domain (MBD) repeat sequences R1 and R4, and the C-terminus, respectively. The antibodies Paired-262 and A-10, but not D-8 and Tau-46, reduced tau fibrillization and degraded preformed tau aggregates, whereas the IVIG reduced tau aggregation but did not alter preformed aggregates. The binding affinities of the antibodies for the epitope for which they were specific did not appear to be related to their effects on tau aggregation. These results confirm that antibody binding to tau's MBD repeat sequences may inhibit tau aggregation and indicate that such antibodies may also degrade preformed tau aggregates. In the presence of anti-tau antibodies, the resulting tau morphologies were antigen-dependent. The results also suggested the possibility of different pathways regulating antibody-mediated inhibition of tau aggregation and antibody-mediated degradation of preformed tau aggregates. PMID:25545358

  13. Aggregation and Aggregation Biases in Production Functions: A Panel Data Analysis of Translog Models

    Biørn, Erik; Skjerpen, Terje

    2002-01-01

    Abstract: An applied econometric study of aggregation, based on an unbalanced panel data set for manu-facturing plants is presented. Panel data are informative in examining aggregation of variables, parameters, and relationships empirically since they (i) allow estimation at both the micro and the macro level, and (ii) enable comparison of the time series properties of the exactly aggre- gated micro relationships with those obtained by performing aggregation by analogy. Numerical aggregati...

  14. Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates

    Gideon Siringi; Ali Abolmaali; Aswath, Pranesh B.

    2015-01-01

    Tire derived aggregate (TDA) has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA) and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of...

  15. Can Aggregation Across Goods be Achieved by Neglecting The Problem? Property Inheritance and Aggregation Bias

    Bertrand M. Koebel

    2002-01-01

    This article studies the problem of composite commodity in two different frameworks. In one case, aggregation across goods is analyzed for elementary goods that satisfy an optimality condition. The unrestricted case is also examined. The notion of an approximate aggregate representation is formalized and shown to be always possible. Can thereby aggregation issues simply be neglected in economic contributions? I show that the standard economic properties of initial functions are not necessaril...

  16. Influence of Aggregate Wettability with Different Lithology Aggregates on Concrete Drying Shrinkage

    Yuanchen Guo; Jueshi Qian; Xue Wang; Zhengyi Yan; Huadong Zhong

    2015-01-01

    The correlation of the wettability of different lithology aggregates and the drying shrinkage of concrete materials is studied, and some influential factors such as wettability and wetting angle are analyzed. A mercury porosimeter is used to measure the porosities of different lithology aggregates accurately, and the pore size ranges that significantly affect the drying shrinkage of different lithology aggregate concretes are confirmed. The pore distribution curve of the different coarse aggr...

  17. Aggregation of Dodecyl 1-Pyrenylmethyl Ether and Its Application in Structure-Polarity Relations of Aggregates

    SANG,Da-Yong; TIAN,Juan; JI,Guo-Zhen

    2006-01-01

    The aggregation behavior of dodecyl 1-pyrenylmethyl ether was studied in dioxane-water mixture solvents by fluorescence techniques. The labeled pyrenyl group was effective in monitoring the polarity change of its environment during aggregation processes. Based on the structural effects such as chain-length effect, self-coiling effect,and branch-group effect on the polarity of the probe environment, the structure features of aggregates were discussed and have been used to interpret the effect of the structural features on the aggregates formed by three cholesteryl esters and three long chain alkanes.

  18. A Novel Method to Quantify Soil Aggregate Stability by Measuring Aggregate Bond Energies

    Efrat, Rachel; Rawlins, Barry G.; Quinton, John N.; Watts, Chris W.; Whitmore, Andy P.

    2016-04-01

    Soil aggregate stability is a key indicator of soil quality because it controls physical, biological and chemical functions important in cultivated soils. Micro-aggregates are responsible for the long term sequestration of carbon in soil, therefore determine soils role in the carbon cycle. It is thus vital that techniques to measure aggregate stability are accurate, consistent and reliable, in order to appropriately manage and monitor soil quality, and to develop our understanding and estimates of soil as a carbon store to appropriately incorporate in carbon cycle models. Practices used to assess the stability of aggregates vary in sample preparation, operational technique and unit of results. They use proxies and lack quantification. Conflicting results are therefore drawn between projects that do not provide methodological or resultant comparability. Typical modern stability tests suspend aggregates in water and monitor fragmentation upon exposure to an un-quantified amount of ultrasonic energy, utilising a laser granulometer to measure the change in mean weight diameter. In this project a novel approach has been developed based on that of Zhu et al., (2009), to accurately quantify the stability of aggregates by specifically measuring their bond energies. The bond energies are measured operating a combination of calorimetry and a high powered ultrasonic probe, with computable output function. Temperature change during sonication is monitored by an array of probes which enables calculation of the energy spent heating the system (Ph). Our novel technique suspends aggregates in heavy liquid lithium heteropolytungstate, as opposed to water, to avoid exposing aggregates to an immeasurable disruptive energy source, due to cavitation, collisions and clay swelling. Mean weight diameter is measured by a laser granulometer to monitor aggregate breakdown after successive periods of calculated ultrasonic energy input (Pi), until complete dispersion is achieved and bond

  19. Spatial Prediction of Soil Aggregate Stability and Aggregate-Associated Organic Carbon Content at the Catchment Scale Using Geostatistical Techniques

    J.MOHAMMADI; M.H.MOTAGHIAN

    2011-01-01

    The association of organic carbon with secondary parzicles (aggregates) results in its storage and retention in soil. A study was carried out at a catchment covering about 92 km2 to predict spatial variability of soil water-stable aggregates (WSA), mean weight diameter (MWD) of aggregates and organic carbon (OC) content in macro- (> 2 mm), meso- (1-2 mm), and micro-aggregate (< 1 mm) fractions, using geostatistical methods. One hundred and eleven soil samples were c(o)llected at the 0-10 cm depth and fractionated into macro-, meso-, and micro-aggregates by wet sieving. The OC content was determined for each fraction. A greater percentage of water-stable aggregates was found for micro-aggregates, followed by meso-aggregates. Aggregate OC content was greatest in meso-aggregates (9 g kg-1), followed by micro-aggregates (7 g kg-1), while the least OC content was found in macro-aggregates (3 g kg-1). Although a significart effect (P = 0.000) of aggregate size on aggregate OC content was found, however, our findings did not support the model of aggregate hierarchy.Land use had a significant effect (P = 0.073) on aggregate OC content. The coefficients of variation (CVs) for OC contents associated with each aggregate fraction indicated macro-aggregates as the most variable (CV = 71%). Among the aggregate fractions, the micro-aggregate fraction had a lower CV value of 27%. The mean content of WSA ranged from 15% for macro-aggregates to 84% for micro-aggregates. Geostatistical analysis showed that the measured soil variables exhibited differences in their spatial patterns in both magnitude and space at each aggregate size fraction. The relative nugget variance for most aggregate-associated properties was lower than 45%. The range value for the variogram of water-stable aggregates was almost similar (about 3 km) for the three studied aggregate size classes. The range value for the variogram of aggregate-associated OC contents ranged from about 3 km for macro-aggregates

  20. Characterization, Manipulation, and Prediction of Protein Aggregation in Model Systems

    Galm, Lara

    2015-01-01

    Main influencing factors favoring protein aggregation are to be identified regarding solution conditions of the surrounding aqueous solution and regarding physicochemical properties of the model proteins themselves. Based on these experimental results, concepts are developed for manipulation of protein aggregation behavior. Finally, based on selected parameters that significantly impact protein aggregation behavior, approaches are developed to predict protein aggregation propensity.

  1. 21 CFR 864.5700 - Automated platelet aggregation system.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated platelet aggregation system. 864.5700... § 864.5700 Automated platelet aggregation system. (a) Identification. An automated platelet aggregation system is a device used to determine changes in platelet shape and platelet aggregation following...

  2. 21 CFR 1303.13 - Adjustments of aggregate production quotas.

    2010-04-01

    ... Federal Register his final order determining the aggregate production for the basic class of controlled... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Adjustments of aggregate production quotas. 1303... Aggregate Production and Procurement Quotas § 1303.13 Adjustments of aggregate production quotas. (a)...

  3. Evidence From Seven Countries on Whether Inventories Smooth Aggregate Output

    Kenneth D. West

    1988-01-01

    Casual examination of annual postwar data on inventories and aggregate output for seven developed countries -- Canada, France, West Germany, Italy, Japan, United Kingdom, United States -- suggests that in these countries the primary function of aggregate inventories is not to smooth aggregate output in the face of aggregate demand shocks. Japan is a possible exception to this generalization.

  4. Metaconcrete: Engineered aggregates for enhanced dynamic performance

    Mitchell, Stephanie J.

    This work presents the development and investigation of a new type of concrete for the attenuation of waves induced by dynamic excitation. Recent progress in the field of metamaterials science has led to a range of novel composites which display unusual properties when interacting with electromagnetic, acoustic, and elastic waves. A new structural metamaterial with enhanced properties for dynamic loading applications is presented, which is named metaconcrete. In this new composite material the standard stone and gravel aggregates of regular concrete are replaced with spherical engineered inclusions. Each metaconcrete aggregate has a layered structure, consisting of a heavy core and a thin compliant outer coating. This structure allows for resonance at or near the eigenfrequencies of the inclusions, and the aggregates can be tuned so that resonant oscillations will be activated by particular frequencies of an applied dynamic loading. The activation of resonance within the aggregates causes the overall system to exhibit negative effective mass, which leads to attenuation of the applied wave motion. To investigate the behavior of metaconcrete slabs under a variety of different loading conditions a finite element slab model containing a periodic array of aggregates is utilized. The frequency dependent nature of metaconcrete is investigated by considering the transmission of wave energy through a slab, which indicates the presence of large attenuation bands near the resonant frequencies of the aggregates. Applying a blast wave loading to both an elastic slab and a slab model that incorporates the fracture characteristics of the mortar matrix reveals that a significant portion of the supplied energy can be absorbed by aggregates which are activated by the chosen blast wave profile. The transfer of energy from the mortar matrix to the metaconcrete aggregates leads to a significant reduction in the maximum longitudinal stress, greatly improving the ability of the material

  5. Structure and aggregation in model tetramethylurea solutions

    The structure of model aqueous tetramethylurea (TMU) solutions is investigated employing large-scale (32 000, 64 000 particles) molecular dynamics simulations. Results are reported for TMU mole fractions, Xt, ranging from infinite dilution up to 0.07, and for two temperatures, 300 and 330 K. Two existing force fields for TMU-water solutions are considered. These are the GROMOS 53A6 united-atom TMU model combined with SPC/E water [TMU(GROMOS-UA)/W(SPC/E)], and the more frequently employed AMBER03 all-atom force field for TMU combined with the TIP3P water model [TMU(AMBER-AA)/W(TIP3P)]. It is shown that TMU has a tendency towards aggregation for both models considered, but the tendency is significantly stronger for the [TMU(AMBER-AA)/W(TIP3P)] force field. For this model signs of aggregation are detected at Xt = 0.005, aggregation is a well established feature of the solution at Xt = 0.02, and the aggregates increase further in size with increasing concentration. This is in agreement with at least some experimental studies, which report signals of aggregation in the low concentration regime. The TMU aggregates exhibit little structure and are simply loosely ordered, TMU-rich regions of solution. The [TMU(GROMOS-UA)/W(SPC/E)] model shows strong signs of aggregation only at higher concentrations (Xt ≳ 0.04), and the aggregates appear more loosely ordered, and less well-defined than those occurring in the [TMU(AMBER-AA)/W(TIP3P)] system. For both models, TMU aggregation increases when the temperature is increased from 300 to 330 K, consistent with an underlying entropy driven, hydrophobic interaction mechanism. At Xt = 0.07, the extra-molecular correlation length expected for microheterogeneous solutions has become comparable with the size of the simulation cell for both models considered, indicating that even the systems simulated here are sufficiently large only at low concentrations

  6. Development of new non destructive methods for bituminized radioactive waste drums characterization; Developpement de nouvelles methodes de caracterisation non destructive pour des dechets radioactifs enrobes dans du bitume

    Pin, P

    2004-10-15

    Radioactive waste constitute a major issue for the nuclear industry. One of the key points is their characterization to optimize their management: treatment and packaging, orientation towards the suited disposal. This thesis proposes an evaluation method of the low-energy photon attenuation, based on the gamma-ray spectra Compton continuum. Effectively, the {sup 241}Am measurement by gamma-ray spectrometry is difficult due to the low energy of its main gamma-ray (59.5 keV). The photon attenuation strongly depends on the bituminous mix composition, which includes very absorbing elements. As the Compton continuum also depends on this absorption, it is possible to link the 59.5 keV line attenuation to the Compton level. Another technique is proposed to characterize uranium thanks to its fluorescence X-rays induced by the gamma emitters already present in the waste. The uranium present in the drums disturbs the neutron measurements and its measurement by self-induced X-ray fluorescence allows to correct this interference. Due to various causes of error, the total uncertainty is around 50 % on the activity of the radioisotope {sup 241}Am, corrected by the peak to Compton technique. The same uncertainty is announced on the uranium mass measured by self induced X-ray fluorescence. As a consequence of these promising results, the two methods were included in the industrial project of the 'Marcoule Sorting Unit'. One major advantage is that they do not imply any additional material because they use information already present in the gamma-ray spectra. (author)

  7. Evaluation of Control Strategies to Effectively Meet 70-90% Mercury Reduction on an Eastern Bituminous Coal Cyclone Boiler with SCR

    Tom Campbell

    2008-12-31

    This is the final site report for testing conducted at Public Service of New Hampshire's (PSNH) Merrimack Unit 2 (MK2). This project was funded through the DOE/NETL Innovations for Existing Plants program. It was a Phase III project with the goal to develop mercury control technologies that can achieve 50-70% mercury capture at costs 25-50% less than baseline estimates of $50,000-$70,000/lb of mercury removed. While results from testing at Merrimack indicate that the DOE goal was partially achieved, further improvements in the process are recommended. Merrimack burned a test blend of eastern bituminous and Venezuelan coals, for a target coal sulfur content of 1.2%, in its 335-MW Unit 2. The blend ratio is approximately a 50/50 split between the two coals. Various sorbent injection tests were conducted on the flue gas stream either in front of the air preheater (APH) or in between the two in-series ESPs. Initial mercury control evaluations indicated that, without SO3 control, the sorbent concentration required to achieve 50% control would not be feasible, either economically or within constraints specific to the maximum reasonable particle loading to the ESP. Subsequently, with SO{sub 3} control via trona injection upstream of the APH, economically feasible mercury removal rates could be achieved with PAC injection, excepting balance-of-plant concerns. The results are summarized along with the impacts of the dual injection process on the air heater, ESP operation, and particulate emissions.

  8. SENSOR indicator framework, and methods for aggregation/dis-aggregation - a guideline

    Frederiksen, P.; Kristensen, P.; Briquel, V.;

    This report collects three guideline contributions to Sensor: the development and proposal of an indicator framework for sustainability impact assessment and criteria for indicator selection, an assessment of international indicator sets for identification of potential indicators for SENSOR impac...... issues, and a description of problems and methodologies for aggregation and dis-aggregation of data and indicators....

  9. Metastable Fractal Aggregates as a Result of Competition Between Diffusion-Limited Aggregation and Dissociation

    Gordienko, Yuriy G

    2015-01-01

    The cellular automaton model is used to simulate diffusion and aggregation with dissociation of point particles in 2D. A continuous phase transition is found that separates creation of compact aggregates and fractal ones. The transition is the function of pair-interaction energy ($E_b$), type of neighborhood and temperature $T$. Manifestations of the transition in real physical systems are discussed.

  10. Soil aggregation under different management systems

    Cibele Mascioli Rebello Portella

    2012-12-01

    Full Text Available Considering that the soil aggregation reflects the interaction of chemical, physical and biological soil factors, the aim of this study was evaluate alterations in aggregation, in an Oxisol under no-tillage (NT and conventional tillage (CT, since over 20 years, using as reference a native forest soil in natural state. After analysis of the soil profile (cultural profile in areas under forest management, samples were collected from the layers 0-5, 5-10, 10-20 and 20-40 cm, with six repetitions. These samples were analyzed for the aggregate stability index (ASI, mean weighted diameter (MWD, mean geometric diameter (MGD in the classes > 8, 8-4, 4-2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm, and for physical properties (soil texture, water dispersible clay (WDC, flocculation index (FI and bulk density (Bd and chemical properties (total organic carbon - COT, total nitrogen - N, exchangeable calcium - Ca2+, and pH. The results indicated that more intense soil preparation (M < NT < PC resulted in a decrease in soil stability, confirmed by all stability indicators analyzed: MWD, MGD, ASI, aggregate class distribution, WDC and FI, indicating the validity of these indicators in aggregation analyses of the studied soil.

  11. Aggregate Particles in the Plumes of Enceladus

    Gao, Peter; Zhang, Xi; Ingersoll, Andrew P

    2015-01-01

    Estimates of the total particulate mass of the plumes of Enceladus are important to constrain theories of particle formation and transport at the surface and interior of the satellite. We revisit the calculations of Ingersoll and Ewald (2011), who estimated the particulate mass of the Enceladus plumes from strongly forward scattered light in Cassini ISS images. We model the plume as a combination of spherical particles and irregular aggregates resulting from the coagulation of spherical monomers, the latter of which allows for plumes of lower particulate mass. Though a continuum of solutions are permitted by the model, the best fits to the ISS data consist either of low mass plumes composed entirely of small aggregates or high mass plumes composed of large aggregates and spheres. The high mass plumes can be divided into a population of large aggregates with total particulate mass of 116 +/- 12 X 10^3 kg, and a mixed population of spheres and aggregates consisting of a few large monomers that has a total plume...

  12. Lanosterol reverses protein aggregation in cataracts.

    Zhao, Ling; Chen, Xiang-Jun; Zhu, Jie; Xi, Yi-Bo; Yang, Xu; Hu, Li-Dan; Ouyang, Hong; Patel, Sherrina H; Jin, Xin; Lin, Danni; Wu, Frances; Flagg, Ken; Cai, Huimin; Li, Gen; Cao, Guiqun; Lin, Ying; Chen, Daniel; Wen, Cindy; Chung, Christopher; Wang, Yandong; Qiu, Austin; Yeh, Emily; Wang, Wenqiu; Hu, Xun; Grob, Seanna; Abagyan, Ruben; Su, Zhiguang; Tjondro, Harry Christianto; Zhao, Xi-Juan; Luo, Hongrong; Hou, Rui; Perry, J Jefferson P; Gao, Weiwei; Kozak, Igor; Granet, David; Li, Yingrui; Sun, Xiaodong; Wang, Jun; Zhang, Liangfang; Liu, Yizhi; Yan, Yong-Bin; Zhang, Kang

    2015-07-30

    The human lens is comprised largely of crystallin proteins assembled into a highly ordered, interactive macro-structure essential for lens transparency and refractive index. Any disruption of intra- or inter-protein interactions will alter this delicate structure, exposing hydrophobic surfaces, with consequent protein aggregation and cataract formation. Cataracts are the most common cause of blindness worldwide, affecting tens of millions of people, and currently the only treatment is surgical removal of cataractous lenses. The precise mechanisms by which lens proteins both prevent aggregation and maintain lens transparency are largely unknown. Lanosterol is an amphipathic molecule enriched in the lens. It is synthesized by lanosterol synthase (LSS) in a key cyclization reaction of a cholesterol synthesis pathway. Here we identify two distinct homozygous LSS missense mutations (W581R and G588S) in two families with extensive congenital cataracts. Both of these mutations affect highly conserved amino acid residues and impair key catalytic functions of LSS. Engineered expression of wild-type, but not mutant, LSS prevents intracellular protein aggregation of various cataract-causing mutant crystallins. Treatment by lanosterol, but not cholesterol, significantly decreased preformed protein aggregates both in vitro and in cell-transfection experiments. We further show that lanosterol treatment could reduce cataract severity and increase transparency in dissected rabbit cataractous lenses in vitro and cataract severity in vivo in dogs. Our study identifies lanosterol as a key molecule in the prevention of lens protein aggregation and points to a novel strategy for cataract prevention and treatment. PMID:26200341

  13. Web Data Aggregation in MOLAP: Approach, Language, and Implementation

    ZHU Yan; TANG Hui-jia; MA Yong-qiang

    2007-01-01

    This paper investigates the Web data aggregation issues in multidimensional on-line analytical processing (MOLAP) and presents a rule-driven aggregation approach. The core of the approach is defining aggregate rules. To define the rules for reading warehouse data and computing aggregates, a rule definition language - array aggregation language (AAL) is developed. This language treats an array as a function from indexes to values and provides syntax and semantics based on monads. External functions can be called in aggregation rules to specify array reading, writing, and aggregating. Based on the features of AAL, array operations are unified as function operations, which can be easily expressed and automatically evaluated. To implement the aggregation approach, a processor for computing aggregates over the base cube and for materializing them in the data warehouse is built, and the component structure and working principle of the aggregation processor are introduced.

  14. Organic carbon, water repellency and soil stability to slaking at aggregate and intra-aggregate scales

    Jordán López, Antonio; García-Moreno, Jorge; Gordillo-Rivero, Ángel J.; Zavala, Lorena M.; Cerdà, Artemi; Alanís, Nancy; Jiménez-Compán, Elizabeth

    2015-04-01

    Water repellency (WR) is a property of some soils that inhibits or delays water infiltration between a few seconds and days or weeks. Inhibited or delayed infiltration contributes to ponding and increases runoff flow generation, often increasing soil erosion risk. In water-repellent soils, water infiltrates preferentially through cracks or macropores, causing irregular soil wetting patterns, the development of preferential flow paths and accelerated leaching of nutrients. Although low inputs of hydrophobic organic substances and high mineralization rates lead to low degrees of WR in cropped soils, it has been reported that conservative agricultural practices may induce soil WR. Although there are many studies at catchment, slope or plot scales very few studies have been carried out at particle or aggregate scale. Intra-aggregate heterogeneity of physical, biological and chemical properties conditions the transport of substances, microbial activity and biochemical processes, including changes in the amount, distribution and chemical properties of organic matter. Some authors have reported positive relationships between soil WR and aggregate stability, since it may delay the entry of water into aggregates, increase structural stability and contribute to reduce soil erosion risk. Organic C (OC) content, aggregate stability and WR are therefore strongly related parameters. In the case of agricultural soils, where both the type of management as crops can influence all these parameters, it is important to evaluate the interactions among them and their consequences. Studies focused on the intra-aggregate distribution of OC and WR are necessary to shed light on the soil processes at a detailed scale. It is extremely important to understand how the spatial distribution of OC in soil aggregates can protect against rapid water entry and help stabilize larger structural units or lead to preferential flow. The objectives of this research are to study [i] the OC content and the

  15. Effects of Titanium Dioxide Nanoparticle Aggregate Size on Gene Expression

    Junko Okuda-Shimazaki; Saiko Takaku; Koki Kanehira; Shuji Sonezaki; Akiyohshi Taniguchi

    2010-01-01

    Titanium dioxide (titania) nanoparticle aggregation is an important factor in understanding cytotoxicity. However, the effect of the aggregate size of nanoparticles on cells is unclear. We prepared two sizes of titania aggregate particles and investigated their biological activity by analyzing biomarker expression based on mRNA expression analysis. The aggregate particle sizes of small and large aggregated titania were 166 nm (PDI = 0.291) and 596 nm (PDI = 0.417), respectively. These two siz...

  16. Effects of Particle Shape on Mechanical Properties of Aggregates

    Benediktsson, Stefán

    2015-01-01

    Aggregates are one of the primary building material used in the world. The durability of construction aggregates will therefore depend upon the quality of aggregate mechanical properties. It is therefore important to understand how particle shape will effect mechanical properties of aggregates, measured by the Los Angeles and micro-Deval values. In order to assess the influence of particle shape on aggregate mechanical properties, the proportion of flaky and cubic particles, measured by the f...

  17. ACCOUNTING FOR AGGREGATION BIAS IN ALMOST IDEAL DEMAND SYSTEMS

    Mittelhammer, Ronald C.; Shi, Hongqi; Wahl, Thomas I.

    1996-01-01

    This study revisits the consistent aggregation (over households) property of almost ideal demand system (AIDS) models and presents a method to explicitly account for expenditure aggregation bias when estimating the aggregate AIDS model with time-series data. Ignoring aggregation bias can lead to biased and inconsistent parameter estimates and can cause aggregate demand functions to be inconsistent with the demand functions at the individual household level. Recognizing the general limited inf...

  18. Environmental Sustainability by Use of Recycled Aggregates - An Overview

    D. K. Gandhi; A. A. Gudadhe

    2014-01-01

    Optimum utilization of available natural resources is the major component to achieve the environmental sustainability. Development in urban infrastructure demands for large quantity of aggregates for construction. Infrastructural waste in the form of demolished aggregates is one of the major components of solid waste. By efficient use of these demolished aggregates in the form of recycled aggregates along with fresh aggregates can achieve a better solid waste management and al...

  19. Secure Data Aggregation Using Reliable Nodes for Wireless Sensor Networks

    M.Y. Mohamed Yacoab; V. Sundaram

    2013-01-01

    Generally, aggregation techniques in Wireless Sensor Networks (WSNs) are defenseless against various attacks. The aggregator and aggregated data has to be secured to assure integrity and confidentiality. In this study, we propose a secure data aggregation technique with reliable nodes using key predicate test protocol for sensor network. This technique specialize some nodes as Reliable nodes (R-nodes) to monitor the process of aggregation. Initially, for each node, a secret key is shared betw...

  20. Skyline-Based Aggregator Node Selection in Wireless Sensor Networks

    Aziz Nasridinov; Sun-Young Ihm; Young-Ho Park

    2013-01-01

    In order to achieve the equal usage of limited resources in the wireless sensor networks (WSNs), we must aggregate the sensor data before passing it to the base station. In WSNs, the aggregator nodes perform a data aggregation process. Careful selection of the aggregator nodes in the data aggregation process results in reducing large amounts of communication traffic in the WSNs. However, network conditions change frequently due to sharing of resources, computation load, and congestion on netw...

  1. Influence of crushed stone aggregate type on concrete consistency

    Topličić-Ćurčić Gordana; Grdić Zoran; Despotović Iva; Ristić Nenad

    2010-01-01

    The main reason for usage of crushed stone mineral aggregate is need for concrete construction building with care about environmental protection, water resources, etc. Influence of crushed stone mineral aggregate on concrete consistency is considered in this paper. River aggregate is used as a benchmark, and from crushed aggregates: limestone, andesite, diabase and basalt. The drawn conclusion is that fine crushed aggregate has an important influence on concrete consistency because it decreas...

  2. Multi-Dimensional Aggregation for Temporal Data

    Böhlen, M. H.; Gamper, J.; Jensen, Christian Søndergaard

    2006-01-01

    Business Intelligence solutions, encompassing technologies such as multi-dimensional data modeling and aggregate query processing, are being applied increasingly to non-traditional data. This paper extends multi-dimensional aggregation to apply to data with associated interval values that capture...... when the data hold. In temporal databases, intervals typically capture the states of reality that the data apply to, or capture when the data are, or were, part of the current database state. This paper proposes a new aggregation operator that addresses several challenges posed by interval data. First......, the intervals to be associated with the result tuples may not be known in advance, but depend on the actual data. Such unknown intervals are accommodated by allowing result groups that are specified only partially. Second, the operator contends with the case where an interval associated with data expresses...

  3. Influence of polysaccharides on wine protein aggregation.

    Jaeckels, Nadine; Meier, Miriam; Dietrich, Helmut; Will, Frank; Decker, Heinz; Fronk, Petra

    2016-06-01

    Polysaccharides are the major high-molecular weight components of wines. In contrast, proteins occur only in small amounts in wine, but contribute to haze formation. The detailed mechanism of aggregation of these proteins, especially in combination with other wine components, remains unclear. This study demonstrates the different aggregation behavior between a buffer and a model wine system by dynamic light scattering. Arabinogalactan-protein, for example, shows an increased aggregation in the model wine system, while in the buffer system a reducing effect is observed. Thus, we could show the importance to examine the behavior of wine additives under conditions close to reality, instead of simpler buffer systems. Additional experiments on melting points of wine proteins reveal that only some isoforms of thaumatin-like proteins and chitinases are involved in haze formation. We can confirm interactions between polysaccharides and proteins, but none of these polysaccharides is able to prevent haze in wine. PMID:26830558

  4. On Aggregating Human Capital Across Heterogeneous Cohorts

    Growiec, Jakub; Groth, Christian

    Based on a general framework for computing the aggregate human capital stock under heterogeneity across population cohorts, the paper derives aggregate human capital stocks in the whole population and in the labor force, and relates these variables to average years of schooling and average work...... experience. Under the scenarios considered here, the "macro-Mincer" (log-linear) relationship between aggregate human capital and average years of schooling is obtained only in cases which are inconsistent with heterogeneity in years of schooling and based on empirically implausible demographic survival laws....... Our numerical results indicate that the macro-Mincer equation can be a reasonable approximation of the true relationship only if returns to schooling and work experience are roughly constant across countries...

  5. Patterns of platelet aggregation in menstrual migraine.

    Allais, G; Facco, G; Ciochetto, D; De Lorenzo, C; Fiore, M; Benedetto, C

    1997-12-01

    We investigated the threshold of the platelet release reaction during the luteal phase of the cycle in 46 patients suffering from menstrual migraine (MM) and 27 healthy normal women. The distribution in both groups of the three types of aggregometric curves (types 1, 2 or 3) obtained in response to ADP 1 microM as aggregating agent was evaluated. Among MM sufferers, 19 (41%) showed a type 1 curve, while 14 (31%) had a type 2 curve and 13 (28%) showed an irreversible aggregation with a type 3 pattern. Curve distribution in controls was 18 (67%) for type 1, 8 (30%) for type 2 and 1 (3%) for type 3. A significantly (p < 0.05) different distribution of the three curve types between MM and controls was present, suggesting that a secondary wave of aggregation is more frequent in MM; the highest difference was due to the observed frequencies of type 3 curves. PMID:9496778

  6. Aggregate ranking of the world's leading universities

    Vladimir M. Moskovkin

    2015-06-01

    Full Text Available The paper presents a methodology for calculating the aggregate global university ranking (Aggregated Global University Ranking, or AGUR, which consists of an automated presentation of the comparable lists of names for different universities from particular global university rankings (using Machine Learning and Mining Data algorithms and a simple procedure of aggregating particular global university rankings (summing up the university ranking positions from different particular rankings and their subsequent ranking. The second procedure makes it possible to bring lists of universities from particular rankings, which are nonidentical by length, to one size. The paper includes a sample AGUR for six particular global university rankings as of 2013, as well as cross-correlation matrices and intersection matrices for AGUR for 2011-2013, all created by means of using the Python-based software.

  7. Aggregation of Calcium Silicate Hydrate Nanoplatelets.

    Delhorme, Maxime; Labbez, Christophe; Turesson, Martin; Lesniewska, Eric; Woodward, Cliff E; Jönsson, Bo

    2016-03-01

    We study the aggregation of calcium silicate hydrate nanoplatelets on a surface by means of Monte Carlo and molecular dynamics simulations at thermodynamic equilibrium. Calcium silicate hydrate (C-S-H) is the main component formed in cement and is responsible for the strength of the material. The hydrate is formed in early cement paste and grows to form platelets on the nanoscale, which aggregate either on dissolving cement particles or on auxiliary particles. The general result is that the experimentally observed variations in these dynamic processes generically called growth can be rationalized from interaction free energies, that is, from pure thermodynamic arguments. We further show that the surface charge density of the particles determines the aggregate structures formed by C-S-H and thus their growth modes. PMID:26859614

  8. SUMO modulation of protein aggregation and degradation

    Marco Feligioni

    2015-09-01

    Full Text Available Small ubiquitin-like modifier (SUMO conjugation and binding to target proteins regulate a wide variety of cellular pathways. The functional aspects of SUMOylation include changes in protein-protein interactions, intracellular trafficking as well as protein aggregation and degradation. SUMO has also been linked to specialized cellular pathways such as neuronal development and synaptic transmission. In addition, SUMOylation is associated with neurological diseases associated with abnormal protein accumulations. SUMOylation of the amyloid and tau proteins involved in Alzheimer's disease and other tauopathies may contribute to changes in protein solubility and proteolytic processing. Similar events have been reported for α-synuclein aggregates found in Parkinson's disease, polyglutamine disorders such as Huntington's disease as well as protein aggregates found in amyotrophic lateral sclerosis (ALS. This review provides a detailed overview of the impact SUMOylation has on the etiology and pathology of these related neurological diseases.

  9. Wind energy aggregation: A coalitional game approach

    Baeyens, E.

    2011-12-01

    In this paper we explore the extent to which a group of N wind power producers can exploit the statistical benefits of aggregation and quantity risk sharing by forming a willing coalition to pool their variable power to jointly offer their aggregate power output as single entity into a forward energy market. We prove that wind power generators will always improve their expected profit when they aggregate their generated power and use tools from coalitional game theory to design fair sharing mechanisms to allocate the payoff among the coalition participants. We show that the corresponding coalitional game is super-additive and has a nonempty core. Hence, there always exists a mechanism for profit-sharing that makes the coalition stable. However, the game is not convex and the celebrated Shapley value may not belong to the core of the game. An allocation mechanism that minimizes the worst-case dissatisfaction is proposed. © 2011 IEEE.

  10. Extraction of TNT from aggregate soil fractions.

    Williford, C W; Mark Bricka, R

    1999-04-23

    Past explosives manufacture, disposal, and training activities have contaminated soil at many military facilities, posing health and environmental risks through contact, potential detonation, and leaching into ground water. While methods have been confirmed for extraction and measuring explosives concentration in soil, no work has addressed aggregate size material (the >2 mm gravel and cobbles) that often occurs with the smaller soil fractions. This paper describes methods and results for extraction and measurement of TNT (2,4,6-trinitrotoluene) in aggregate material from 1/2 to 2-1/1 from a WWII era ammunition plant. TNT was extracted into acetonitrile by both Soxhlet and ultrasonic extraction methods. High pressure liquid chromatography analyses of extracts showed expected variation among samples. Also effective extraction and determination of TNT concentration for each aggregate size fraction was achieved. PMID:10379027

  11. Internal Aggregation Models on the Comb Lattice

    Huss, Wilfried

    2011-01-01

    The comb C is a natural spanning tree of the Euclidean lattice Z^2. We study three related cluster growth models on C: internal diffusion limited aggregation (IDLA), in which random walkers move on the vertices of C until reaching an unoccupied site where they stop; rotor-router aggregation in which particles perform deterministic walks, and stop when reaching a site previously unoccupied; and the divisible sandpile model where at each vertex there is a pile of sand, for which, at each step, the mass exceeding 1 is distributed equally among the neighbours. We describe the shape of the divisible sandpile cluster on C, which is then used to give inner bounds for IDLA and rotor-router aggregation.

  12. Aggregation kinetics and structure of cryoimmunoglobulins clusters

    De Spirito, M; Bassi, F A; Di Stasio, E; Giardina, B; Arcovito, G

    2002-01-01

    Cryoimmunoglobulins are pathological antibodies characterized by a temperature-dependent reversible insolubility. Rheumatoid factors (RF) are immunoglobulins possessing anti-immunoglobulin activity and usually consist of an IgM antibody that recognizes IgG as antigen. These proteins are present in sera of patients affected by a large variety of different pathologies, such as HCV infection, neoplastic and autoimmune diseases. Aggregation and precipitation of cryoimmunoglobulins, leading to vasculiti, are physical phenomena behind such pathologies. A deep knowledge of the physico-chemical mechanisms regulating such phenomena plays a fundamental role in biological and clinical applications. In this work, a preliminary investigation of the aggregation kinetics and of the final macro- molecular structure of the aggregates is presented. Through static light scattering techniques, the gyration radius R/sub g/ and the fractal dimension D/sub m/ of the growing clusters have been determined. However, while the initial ...

  13. Optical Properties and Aggregation of Graphene Nanoplatelets.

    Melezhyk, A V; Kotov, V A; Tkachev, A G

    2016-01-01

    In the present paper, the optical density of dispersions of randomly oriented multilayer graphene nanoplatelets (GNPs) was estimated. Calculated and experimental data were compared for aqueous GNP dispersions stabilized with various surfactants. It was shown that the sonication of an expanded graphite compound (EGC) in aqueous surfactant solutions leads to the transformation of EGC worm-like particles into weak GNP aggregates which are able to pass into solution upon dilution and agitation of the system. They may be filtered and washed out of surfactants. The concentrated GNP dispersions containing these weak aggregates can be used to synthesize different graphene-based nanostructures and obtain novel composite materials. PMID:27398570

  14. Production of prone-to-aggregate proteins.

    Lebendiker, Mario; Danieli, Tsafi

    2014-01-21

    Expression of recombinant proteins in Escherichia coli (E. coli) remains the most popular and cost-effective method for producing proteins in basic research and for pharmaceutical applications. Despite accumulating experience and methodologies developed over the years, production of recombinant proteins prone to aggregate in E. coli-based systems poses a major challenge in most research applications. The challenge of manufacturing these proteins for pharmaceutical applications is even greater. This review will discuss effective methods to reduce and even prevent the formation of aggregates in the course of recombinant protein production. We will focus on important steps along the production path, which include cloning, expression, purification, concentration, and storage. PMID:24211444

  15. Assays for alpha-synuclein aggregation

    Giehm, Lise; Lorenzen, Nikolai; Otzen, Daniel

    2011-01-01

    aggregates 1. The ability to form amyloid structures has also been exploited by living systems, where proteins forming fibrils during the normal life-cycle have functional rather than disease associated properties 2; 3; 4; 5. Thus, understanding the structural features of fibrils, as well as the processes......Over the last few decades, protein aggregation gone from being an irritating side product in the test tube to becoming a subject of great interest. This has been stimulated by the realization that a large and growing number of diseases is associated with the formation and accumulation of proteins...

  16. Implementation of a social Networks aggregation platform

    Ariño Pla, Daniel

    2009-01-01

    This project is part of an innovation project developed by Telefonica R&D. The project's goal is to develop the SociaLuna platform, which will be an aggregator of different social networks that exist in the Internet. Due to the popularity of social networks on the Internet, users commonly need to sign in into multiple sites to retrieve all their social activity. This fact leads to think of a platform to aggregate social networks, in which a user who is registered in different social networks ...

  17. 200 North Aggregate Area source AAMS report

    1993-06-01

    This report presents the results of an aggregate area management study (AAMS) for the 200 North Aggregate Area in the 200 Areas of the US Department of Energy (DOE) Hanford Site in Washington State. This scoping level study provides the basis for initiating Remedial Investigation/Feasibility Study (RI/FS) activities under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) or Resource Conservation and Recovery Act (RCRA) Facility Investigations (RFI) and Corrective Measures Studies (CMS) under RCRA. This report also integrates select RCRA treatment, storage, or disposal (TSD) closure activities with CERCLA and RCRA past practice investigations.

  18. 200 North Aggregate Area source AAMS report

    This report presents the results of an aggregate area management study (AAMS) for the 200 North Aggregate Area in the 200 Areas of the US Department of Energy (DOE) Hanford Site in Washington State. This scoping level study provides the basis for initiating Remedial Investigation/Feasibility Study (RI/FS) activities under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) or Resource Conservation and Recovery Act (RCRA) Facility Investigations (RFI) and Corrective Measures Studies (CMS) under RCRA. This report also integrates select RCRA treatment, storage, or disposal (TSD) closure activities with CERCLA and RCRA past practice investigations

  19. Effect of urea on biomimetic aggregates

    F.H. Florenzano

    1997-02-01

    Full Text Available The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic, monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied, which leads to an increase in the area per headgroup and also in the loss of counterion affinities

  20. Effect of urea on biomimetic aggregates.

    Florenzano, F H; Politi, M J

    1997-02-01

    The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers) was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic), monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied), which leads to an increase in the area per headgroup and also in the loss of counterion affinities. PMID:9239302

  1. Average Shape of Transport-Limited Aggregates

    Davidovitch, Benny; Choi, Jaehyuk; Bazant, Martin Z.

    2005-08-01

    We study the relation between stochastic and continuous transport-limited growth models. We derive a nonlinear integro-differential equation for the average shape of stochastic aggregates, whose mean-field approximation is the corresponding continuous equation. Focusing on the advection-diffusion-limited aggregation (ADLA) model, we show that the average shape of the stochastic growth is similar, but not identical, to the corresponding continuous dynamics. Similar results should apply to DLA, thus explaining the known discrepancies between average DLA shapes and viscous fingers in a channel geometry.

  2. Aggregate composition and stability of structural aggregates of non-calcareous rendzinas in Eastern Serbia

    Gajić Boško

    2006-01-01

    Full Text Available The present study includes the results of comparative investigations of aggregate composition and water stability of structural aggregates in humus horizons of non-calcareous rendzina under native forest and pasture vegetations and the same rendzina utilized long-term as arable field. The results show that aggregate composition and water stability of structural aggregates in the cultivated non-calcareous rendzina are significantly impaired due to a long-term anthropogenization. In the cultivated rendzinas the content of agronomically most valuable aggregates (0.25-10 mm significantly decreased, while the percentage of cloddy aggregates (>10 mm was increased about 1.5 to 3.5 times in comparison with the rendzina under pasture and forest vegetations. The structure coefficient of cultivated soils was lower (2.61 than in forest (4.63 and pasture (10.47 rendzinas. The cultivated non-calcareous rendzina had lower (59.12% aggregate water stability than rendzina under pasture (82.66% and forest (91.92%. Mean weight diameters of water stable agregates was higher in forest (1.44 mm and pasture (1.20 mm than in cultivated (0.65 mm rendzina.

  3. Differential survival of solitary and aggregated bacterial cells promotes aggregate formation on leaf surfaces

    Monier, J.-M.; Lindow, S. E.

    2003-01-01

    The survival of individual Pseudomonas syringae cells was determined on bean leaf surfaces maintained under humid conditions or periodically exposed to desiccation stress. Cells of P. syringae strain B728a harboring a GFP marker gene were visualized by epifluorescence microscopy, either directly in situ or after recovery from leaves, and dead cells were identified as those that were stained with propidium iodide in such populations. Under moist, conducive conditions on plants, the proportion of total live cells was always high, irrespective of their aggregated state. In contrast, the proportion of the total cells that remained alive on leaves that were periodically exposed to desiccation stress decreased through time and was only ≈15% after 5 days. However, the fraction of cells in large aggregates that were alive on such plants in both condition was much higher than more solitary cells. Immediately after inoculation, cells were randomly distributed over the leaf surface and no aggregates were observed. However, a very aggregated pattern of colonization was apparent within 7 days, and >90% of the living cells were located in aggregates of 100 cells or more. Our results strongly suggest that, although conducive conditions favor aggregate formation, such cells are much more capable of tolerating environmental stresses, and the preferential survival of cells in aggregates promotes a highly clustered spatial distribution of bacteria on leaf surfaces. PMID:14665692

  4. Influence of Aggregate Wettability with Different Lithology Aggregates on Concrete Drying Shrinkage

    Yuanchen Guo

    2015-01-01

    Full Text Available The correlation of the wettability of different lithology aggregates and the drying shrinkage of concrete materials is studied, and some influential factors such as wettability and wetting angle are analyzed. A mercury porosimeter is used to measure the porosities of different lithology aggregates accurately, and the pore size ranges that significantly affect the drying shrinkage of different lithology aggregate concretes are confirmed. The pore distribution curve of the different coarse aggregates is also measured through a statistical method, and the contact angle of different coarse aggregates and concrete is calculated according to the linear fitting relationship. Research shows that concrete strength is determined by aggregate strength. Aggregate wettability is not directly correlated with concrete strength, but wettability significantly affects concrete drying shrinkage. In all types’ pores, the greatest impacts on wettability are capillary pores and gel pores, especially for the pores of the size locating 2.5–50 nm and 50–100 nm two ranges.

  5. Single particle detection and characterization of synuclein co-aggregation

    Protein aggregation is the key event in a number of human diseases such as Alzheimer's and Parkinson's disease. We present a general method to quantify and characterize protein aggregates by dual-colour scanning for intensely fluorescent targets (SIFT). In addition to high sensitivity, this approach offers a unique opportunity to study co-aggregation processes. As the ratio of two fluorescently labelled components can be analysed for each aggregate separately in a homogeneous assay, the molecular composition of aggregates can be studied even in samples containing a mixture of different types of aggregates. Using this method, we could show that wild-type α-synuclein forms co-aggregates with a mutant variant found in familial Parkinson's disease. Moreover, we found a striking increase in aggregate formation at non-equimolar mixing ratios, which may have important therapeutic implications, as lowering the relative amount of aberrant protein may cause an increase of protein aggregation leading to adverse effects

  6. Aggregation behavior of tin in tin oxides reacted with lithium

    Tin aggregation behavior during charge/discharge of tin oxide electrodes is investigated using Li/Sn2BPO6 and Li/SnO cells. Sn aggregation is identified by the peaks in the derivative capacity vs. voltage plot. Scanning electron microscope, transmission electron microscope, and Auger electron spectroscope are used to investigate the formation and growth of Sn aggregates. Sn aggregation is more prominent when the upper cutoff voltage is higher than 1.0 V, and Sn aggregates continues to grow with cycling. The upper cutoff voltage is the most critical factor for Sn aggregation as it governs the size and growth rate of aggregates, whereas the effect of the lower cutoff voltage on Sn aggregation behavior seems relatively insignificant. Sn aggregation shows limited effect on cycling behavior of tin oxide electrode

  7. Planar aggregation and the coalescing Brownian flow

    Norris, James; Turner, Amanda

    2008-01-01

    We study a scaling limit associated to a model of planar aggregation. The model is obtained by composing certain independent random conformal maps. The evolution of harmonic measure on the boundary of the cluster is shown to converge to the coalescing Brownian flow.

  8. Colloidal Aggregate Structure under Shear by USANS

    Chatterjee, Tirtha; van Dyk, Antony K.; Ginzburg, Valeriy V.; Nakatani, Alan I.

    2015-03-01

    Paints are complex formulations of polymeric binders, inorganic pigments, dispersants, surfactants, colorants, rheology modifiers, and other additives. A commercially successful paint exhibits a desired viscosity profile over a wide shear rate range from 10-5 s-1 for settling to >104 s-1 for rolling, and spray applications. Understanding paint formulation structure is critical as it governs the paint viscosity profile. However, probing paint formulation structure under shear is a challenging task due to the formulation complexity containing structures with different hierarchical length scales and their alterations under the influence of an external flow field. In this work mesoscale structures of paint formulations under shear are investigated using Ultra Small-Angle Neutron Scattering (rheo-USANS). Contrast match conditions were utilized to independently probe the structure of latex binder particle aggregates and the TiO2 pigment particle aggregates. Rheo-USANS data revealed that the aggregates are fractal in nature and their self-similarity dimensions and correlations lengths depend on the chemistry of the binder particles, the type of rheology modifier present and the shear stress imposed upon the formulation. These results can be explained in the framework of diffusion and reaction limited transient aggregates structure evolution under simple shear.

  9. Aggregate Unemployment Decreases Individual Returns to Education

    Ammermueller, Andreas; Kuckulenz, Anja; Zwick, Thomas

    2009-01-01

    Aggregate unemployment may affect individual returns to education through qualification-specific responses in participation and wage bargaining. This paper shows that an increase in regional unemployment by 1% decreases returns to education by 0.005 percentage points. This implies that higher skilled employees are better sheltered from labour…

  10. DENDRIMER CONJUGATES FOR SELECTIVE OF PROTEIN AGGREGATES

    2004-01-01

    Dendrimer conjugates are presented, which are formed between a dendrimer and a protein solubilising substance. Such dendrimer conjugates are effective in the treatment of protein aggregate-related diseases (e.g. prion-related diseases). The protein solubilising substance and the dendrimer together...

  11. Aggregation of log-linear risks

    Embrechts, Paul; Hashorva, Enkeleijd; Mikosch, Thomas Valentin

    2014-01-01

    In this paper we work in the framework of a k-dimensional vector of log-linear risks. Under weak conditions on the marginal tails and the dependence structure of a vector of positive risks, we derive the asymptotic tail behaviour of the aggregated risk {and present} an application concerning log...

  12. Does it Matter How to Measure Aggregates?

    Beyer, Andreas; Juselius, Katarina

    Beyer, Doornik and Hendry (2000, 2001) show analytically that three out of four aggregation methods yield problematic results when exchange rate shifts induce relative-price changes between individual countries and found the least problematic method to be the variable weight method of growth rates...

  13. Generation of Small Enterprises’ Multivariate Sample Aggregates

    Bokun, N. Ch.

    2007-01-01

    The work gives methodology of small enterprises’ multivariate sample aggregates in order to provide more comprehensive statistical evaluation of small institutional units’ economic activity. The strategy is found on usage cluster analysis. The article provides results of small enterprises’ selection carried out in Minsk City.

  14. School Quality, Educational Attainment and Aggregation Bias

    Fertig, Michael; Wright, Robert E.

    2003-01-01

    Data from 31 countries participating in the Programme for International Student Assessment (PISA) is used to estimate education production functions for reading literacy.The analysis suggests that the probability of finding tatistically significant and correctly signed class size effects increases the higher the level of aggregation used to measure class size.

  15. EFFECT OF AGGREGATION ON VIBRIO CHOLERAE INACTIVATION

    Extensive research has shown that microorganisms exhibit increased resistance due to clumping, aggregation, particle association, or modification of antecedent growth conditions. During the course of investigating a major water-borne Vibrio cholerae outbreak in Peru, U.S. EPA inv...

  16. Synchronized Data Aggregation for Wireless Sensor Network

    Dnyaneshwar, Mantri; Prasad, Neeli R.; Prasad, Ramjee

    2014-01-01

    Wireless Sensor Networks (WSNs) are used for monitoring and data collection purposes. A key challenge in effective data collection is to schedule and synchronize the activities of the nodes with global clock. This paper proposes the Synchronized Data Aggregation Algorithm (SDA) using spanning tree...

  17. Immunogenicity of therapeutic proteins: Influence of aggregation

    Ratanji, Kirsty D.; Derrick, Jeremy P.; Dearman, Rebecca J; Kimber, Ian

    2013-01-01

    The elicitation of anti-drug antibodies (ADA) against biotherapeutics can have detrimental effects on drug safety, efficacy, and pharmacokinetics. The immunogenicity of biotherapeutics is, therefore, an important issue. There is evidence that protein aggregation can result in enhanced immunogenicity; however, the precise immunological and biochemical mechanisms responsible are poorly defined. In the context of biotherapeutic drug development and safety assessment, understanding the mechanisms...

  18. Ring aggregation pattern of Human Travel Trips

    Wang, Zi-Yang; Zhu, Peng; Qin, Yong; Jia, Li-Min

    2015-01-01

    Although a lot of attentions have been paid to human mobility, the relationship between travel pattern with city structure is still unclear. Here we probe into this relationship by analyzing the metro passenger trip data.There are two unprecedented findings. One, from the average view a linear law exists between the individual's travel distance with his original distance to city center. The mechanism underlying is a travel pattern we called "ring aggregation", i.e., the daily movement of city passengers is just aggregating to a ring with roughly equal distance to city center.Interestingly, for the round trips the daily travel pattern can be regarded as a switching between the home ring at outer area with the office ring at the inner area. Second, this linear law and ring aggregation pattern seems to be an exclusive characteristic of the metro system. It can not be found in short distance transportation modes, such as bicycle and taxi, neither as multiple transportation modes. This means the ring aggregation p...

  19. Studies of the aggregation of RNase Sa

    Khasa, Harshit; Kramer, Ryan; Maddux, Nathan; Hamborg, Mette; Joshi, Sangeeta B; Volkin, David B; Middaugh, C Russell

    2014-01-01

    Thirty-eight mutants of RNase Sa (ribonuclease from Streptomyces aureofaciens) were examined for their structure, thermal sensitivity, and tendency to aggregate. Although a biphasic correlation was seen between the effect of temperature on structure and the free energy of transfer changes in many...

  20. An Aß concatemer with altered aggregation propensities

    Giehm, L; Dal Degan, F; Fraser, P; Klysner, S; Otzen, Daniel E

    2010-01-01

    tetanus toxin. Even in the presence of high concentrations of denaturants or fluorinated alcohols, Con-Alz has a very high propensity to form aggregates which slowly coalesce over time with changes in secondary, tertiary and quaternary structure. Only micellar concentrations of SDS were able to inhibit...

  1. Utilitarian Aggregation of Beliefs and Tastes.

    Gilboa, Itzhak; Samet, Dov; Schmeidler, David

    2004-01-01

    Harsanyi's utilitarianism is extended here to Savage's framework. We formulate a Pareto condition that implies that both society's utility function and its probability measure are linear combinations of those of the individuals. An indiscriminate Pareto condition has been shown to contradict linear aggregation of beliefs and tastes. We argue that…

  2. Small file aggregation in a parallel computing system

    Faibish, Sorin; Bent, John M.; Tzelnic, Percy; Grider, Gary; Zhang, Jingwang

    2014-09-02

    Techniques are provided for small file aggregation in a parallel computing system. An exemplary method for storing a plurality of files generated by a plurality of processes in a parallel computing system comprises aggregating the plurality of files into a single aggregated file; and generating metadata for the single aggregated file. The metadata comprises an offset and a length of each of the plurality of files in the single aggregated file. The metadata can be used to unpack one or more of the files from the single aggregated file.

  3. Microbial activity in argillite waste storage cells for the deep geological disposal of French bituminous medium activity long lived nuclear waste: Impact on redox reaction kinetics and potential

    Albrecht, A.; Leone, L.; Charlet, L.

    2009-04-01

    Micro-organisms are ubiquitous and display remarkable capabilities to adapt and survive in the most extreme environmental conditions. It has been recognized that microorganisms can survive in nuclear waste disposal facilities if the required major (P, N, K) and trace elements, a carbon and energy source as well as water are present. The space constraint is of particular interest as it has been shown that bacteria do not prosper in compacted clay. An evaluation of the different types of French medium and high level waste, in a clay-rich host rock storage environment at a depth between 500 and 600 m, has shown that the bituminous waste is the most likely candidate to accommodate significant microbial activity. The waste consists of a mixture of bitumen (source of bio-available organic matter and H2 as a consequence of its degradation and radiolysis) and nitrates and sulphates kept in a stainless steel container. The assumption, that microbes only have an impact on reaction kinetics needs to be reassessed in the case where nitrates and sulphates are present since both are known not to react at low temperatures without bacterial catalysis. The additional impact of both oxy-anions and their reduced species on redox conditions, radionuclide speciation and mobility gives this evaluation their particular relevance. Storage architecture proposes four primary waste containers positioned into armoured cement over packs and placed with others into the waste storage cell itself composed of a cement mantle enforcing the argillite host rock, the latter being characterized by an excavation damaged zone constricted both in space and in time and a pristine part of 60 m thickness. Bacterial activity within the waste and within the pristine argillite is disregarded because of the low water activity (low mobility of critical RN, • increased retardation of mobile RN in biofilms (i.e. adsorption on microbial cell surfaces and products of possible biomineralization); complexation by

  4. Parametric and dynamic studies of an iron-based 25-kWth coal direct chemical looping unit using sub-bituminous coal

    Highlights: • Integrated, moving bed chemical looping reactor with iron-oxide based oxygen carrier. • Coal carbon conversion from 84.8% to 99.9%, thermal capacity 7.4 to 27.7 kWth, O2 demand less than 1.3%. • Dynamic temperature of moving bed reducer is established and tracked during coal injection. • CH4 and CO present at initial coal injection, eliminated after oxygen carrier activated. • Lower coal injection had higher volatiles residence time and conversion. - Abstract: The iron-based Coal-Direct Chemical Looping (CDCL) combustion process is an alternative to conventional oxy-combustion technologies, where the oxygen used for fuel conversion in the CDCL process is provided by an iron-oxide based oxygen carrier instead of an air separation unit. The iron oxide is reduced using coal in the reducer reactor, producing highly-pure CO2 in the flue gas, and the reduced iron oxide is regenerated in a separate combustor reactor using air. The CDCL process at Ohio State has been developed and demonstrated in a 25 kWth sub-pilot unit, and it is the first chemical looping demonstration unit with a circulating moving bed reactor for solid fuel conversion. To date, the CDCL sub-pilot unit at OSU has been operated for more than 680 h, with a 200-h continuous operation, providing important data on long term operability as well as parametric optimization. This paper discusses recent parametric operational experience with sub-bituminous coal as the fuel, where dynamic changes in variables were performed to observe the effects on the unit itself. Measurements included temperature, pressure, and gas concentrations from the reducer and combustor. Furthermore, effects of different variables, such as flue gas recycle ratios (enhancer gas flow rates), feed port injection, and temperature, were observed. Tests confirmed high coal conversions with high purity of CO2 achieved in the flue gas. Overall, the moving bed design of the reducer results in nearly full coal conversion

  5. Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates

    Gideon Siringi

    2015-01-01

    Full Text Available Tire derived aggregate (TDA has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of rupture (flexural strength based on ASTM C78, and bond stress based on ASTM C234. Results indicate that while replacement of coarse aggregates with TDA results in reduction in strength, it may be mitigated with addition of silica fume to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product while utilizing recycled TDA.

  6. Influence of granitic aggregates from Northeast Brazil on the alkali-aggregate reaction

    Gomes Neto, David de Paiva; Santana, Rodrigo Soares de; Barreto, Ledjane Silva, E-mail: pvgomes@uol.com.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. de Ciencias dos Materiais e Engenharia; Conceicao, Herbert; Lisboa, Vinicios Anselmo Carvalho [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. de Geologia

    2014-08-15

    The alkali-aggregate reaction (AAR) in concrete structures is a problem that has concerned engineers and researchers for decades. This reaction occurs when silicates in the aggregates react with the alkalis, forming an expanded gel that can cause cracks in the concrete and reduce its lifespan. The aim of this study was to characterize three coarse granitic aggregates employed in concrete production in northeastern Brazil, correlating petrographic analysis with the kinetics of silica dissolution and the evolution of expansions in mortar bars, assisted by SEM/EDS, XRD, and EDX. The presence of grains showing recrystallization into individual microcrystalline quartz subgrains was associated with faster dissolution of silica and greater expansion in mortar bars. Aggregates showing substantial deformation, such as stretched grains of quartz with strong undulatory extinction, experienced slower dissolution, with reaction and expansion occurring over longer periods that could not be detected using accelerated tests with mortar bars. (author)

  7. INVESTIGATIONS ON RECYCLED CONCRETE AGGREGATE AND MSAND AS AGGREGATE REPLACEMENT IN CONCRETE

    Sridhar, U; Karthick, B

    2015-01-01

    Gigantic numbers of building and destruction trashes are produced in emerging countries like India. The clearance of these trashes is serious problem because it requires huge space. The present work is to study the properties of concrete with replacement of 50% of nature sand by manufactured sand and coarse aggregates by different proportions with recycled concrete aggregates (RCA). A mix proportion for M20 grade concrete is derived with standards confirming to IS codes. RCA was p...

  8. iAggregator: Multidimensional Relevance Aggregation Based on a Fuzzy Operator

    Moulahi, Bilel; Tamine, Lynda; Ben Yahia, Sadok

    2014-01-01

    Recently, an increasing number of information retrieval studies have triggered a resurgence of interest in redefining the algorithmic estimation of relevance, which implies a shift from topical to multidimensional relevance assessment. A key underlying aspect that emerged when addressing this concept is the aggregation of the relevance assessments related to each of the considered dimensions. The most commonly adopted forms of aggregation are based on classical weighted means and linear combi...

  9. Biological framework for soil aggregation: Implications for ecological functions.

    Ghezzehei, Teamrat; Or, Dani

    2016-04-01

    Soil aggregation is heuristically understood as agglomeration of primary particles bound together by biotic and abiotic cementing agents. The organization of aggregates is believed to be hierarchical in nature; whereby primary particles bond together to form secondary particles and subsequently merge to form larger aggregates. Soil aggregates are not permanent structures, they continuously change in response to internal and external forces and other drivers, including moisture, capillary pressure, temperature, biological activity, and human disturbances. Soil aggregation processes and the resulting functionality span multiple spatial and temporal scales. The intertwined biological and physical nature of soil aggregation, and the time scales involved precluded a universally applicable and quantifiable framework for characterizing the nature and function of soil aggregation. We introduce a biophysical framework of soil aggregation that considers the various modes and factors of the genesis, maturation and degradation of soil aggregates including wetting/drying cycles, soil mechanical processes, biological activity and the nature of primary soil particles. The framework attempts to disentangle mechanical (compaction and soil fragmentation) from in-situ biophysical aggregation and provides a consistent description of aggregate size, hierarchical organization, and life time. It also enables quantitative description of biotic and abiotic functions of soil aggregates including diffusion and storage of mass and energy as well as role of aggregates as hot spots of nutrient accumulation, biodiversity, and biogeochemical cycles.

  10. Improvement of Bearing Capacity in Recycled Aggregates Suitable for Use as Unbound Road Sub-Base

    Laura Garach; Mónica López; Francisco Agrela; Javier Ordóñez; Javier Alegre; José Antonio Moya

    2015-01-01

    Recycled concrete aggregates and mixed recycled aggregates are specified as types of aggregates with lower densities, higher water absorption capacities, and lower mechanical strength than natural aggregates. In this paper, the mechanical behaviour and microstructural properties of natural aggregates, recycled concrete aggregates and mixed recycled aggregates were compared. Different specimens of unbound recycled mixtures demonstrated increased resistance properties. The formation of new ceme...

  11. On the oxidation of the dissolved organic matter in Boom clay by NaNO3 and NaNO2 from disposed Eurobitum bituminized waste

    Document available in extended abstract form only. In Belgium, Boom Clay is studied as a potential host clay formation for the final disposal of EUROBITUM bituminized waste, which consists of 60 wt% hard bitumen (Mexphalt R85/40) and 40 wt% waste. The main salts that are present in the bituminized waste are NaNO3, 20-30 wt%, and CaSO4, 4-6 wt%. After disposal of the waste in the clay, an uptake of pore water by the embedded, dehydrated and hygroscopic salts will lead to a swelling of the waste and to a release of the salts into the Boom Clay. A possible consequence of the salt release is the oxidation of the clay by nitrate and, possibly, nitrite, resulting in a lower reducing capacity of the clay towards redox sensitive radionuclides, which in turn could have an impact on the migration behaviour of these radionuclides. The extent of oxidation of authigenic Boom Clay redox sensitive components, like organic matter and pyrite is studied at the SCK.CEN. As a first step in the study of the influence of nitrate and nitrite on the redoxactive Boom Clay components, we performed batch tests with dissolved organic matter (DOM). DOM was exposed to different concentrations of nitrate and nitrite for more than one year in both biotic and abiotic conditions. This paper will discuss the results obtained by exposing DOM to nitrate and nitrite and comparing two methods for the determination of its redox capacity. NaNO3 or NaNO2, previously stored under inert atmosphere to remove all oxygen gas, was added to Boom Clay water collected from a piezometer to obtain final salt concentrations of 0.1 and 0.005 M NaNO3, or 0.05 and 0.005 M NaNO2. Sodium azide, also stored under inert atmosphere, was added (0.2 wt. %) to inhibit the microbial activity in the tests, creating abiotic conditions. All solutions were prepared in an anaerobic glove box. The nitrate and nitrite reduction by DOM was followed by analysing the concentrations of nitrate, nitrite and ammonium in the solutions and of

  12. Gut bacteria mediate aggregation in the German cockroach

    Aggregation of the German cockroach, Blattella germanica, is regulated by fecal aggregation agents (pheromones), including volatile carboxylic acids (VCAs). We hypothesized that the gut microbial community contributes to production of these semiochemicals. Chemical analysis of the fecal extract of B...

  13. Shaping the Growth Behaviour of Bacterial Aggregates in Biofilms

    Melaugh, Gavin; Kragh, Kasper Nørskov; Irie, Yasuhiko; Roberts, Aled; Bjarnsholt, Thomas; Diggle, Steve P; Gordon, Vernita; Allen, Rosalind J

    2015-01-01

    Bacterial biofilms are usually assumed to originate from individual cells deposited on a surface. However, many biofilm-forming bacteria tend to aggregate in the planktonic phase meaning it is possible that many natural and infectious biofilms originate wholly or partially from pre-formed cell aggregates. Here, we use agent-based computer simulations to investigate the role of pre-formed aggregates in biofilm development. Focusing on the role of aggregate shape, we find that the degree of spreading of an aggregate on a surface can play a key role in determining its eventual fate during biofilm development. Specifically, initially spread aggregates perform better when competition with surrounding bacterial cells is low, while initially rounded aggregates perform better when competition is high. These contrasting outcomes are governed by a trade-off between aggregate surface area and height. Our results provide new insight into biofilm formation and development, and reveal new factors that may be at play in the...

  14. 47 CFR 10.300 - Alert aggregator. [Reserved

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Alert aggregator. 10.300 Section 10.300 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM System Architecture § 10.300 Alert aggregator....

  15. Environmental Sustainability by Use of Recycled Aggregates - An Overview

    D. K. Gandhi

    2014-05-01

    Full Text Available Optimum utilization of available natural resources is the major component to achieve the environmental sustainability. Development in urban infrastructure demands for large quantity of aggregates for construction. Infrastructural waste in the form of demolished aggregates is one of the major components of solid waste. By efficient use of these demolished aggregates in the form of recycled aggregates along with fresh aggregates can achieve a better solid waste management and also cope up with the rising demands of aggregates leading to economy. Present study is an attempt to increase the awareness about economical viability and technical feasibility for the use of recycled aggregates as a construction material in concrete and to show that the use of recycled aggregates is also an efficient measure to reduce the intensity of environmental impact.

  16. Diffusion-limited aggregation on the hyperbolic plane

    Eldan, Ronen

    2015-01-01

    We consider an analogous version of the diffusion-limited aggregation model defined on the hyperbolic plane. We prove that almost surely the aggregate viewed at time infinity will have a positive density.

  17. Thermal relaxation of bituminous coal to improve donation ability of hydrogen radicals in flash pyrolysis; Sekitan kozo kanwa ni yoru suiso radical kyoyo noryoku no kojo wo mezashita netsubunkai mae shori

    Mori, T.; Isoda, T.; Kusakabe, K.; Morooka, S. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Hayashi, J. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology

    1996-10-28

    In terms of coal conversion reaction, the behavior of bituminous coal heated beyond a glass transition point was examined on the basis of pyrolyzed products, and the effect of an increase in proton mobility on promotion of coal decomposition was evaluated. In experiment, after Illinois bituminous coal specimen was heated up to a specific temperature in N2 or He gas flow at a rate of 5K/min, the specimen was directly transferred to a pyrolyzer for instantaneous pyrolysis. As the experimental result, the glass transition temperature of the Illinois coal specimen was calculated to be 589K from a differential scanning calorimetry (DSC) profile. From the pyrolysis result of the Illinois coal specimen heated up to 623K, the char yield decreased by 3kg as compared with that of the original coal, while the tar yield increased by 4kg up to 27kg per 100kg of the original coal. This tar increase was larger than that of cooled coal. These results suggested that the donation of hydrogen radicals to coal fragments is improved with an increase in proton mobility. 4 refs., 4 figs., 1 tab.

  18. Study of stabilization/solidification processes (of solid porous wastes) based on hydraulic or bituminous binders; Etude des procedes de stabilisation/solidification (des dechets solides poreux) a base de liants hydrauliques ou de liants bitumineux

    Sing-Teniere, Ch.

    1998-02-01

    The first part of this thesis presents the regulatory framework and the technical context linked with the study of stabilized/solidified wastes and with the evaluation of stabilization/solidification processes. A presentation of the two type of ultimate wastes under study (a used catalyst and an activated charcoal) and an analysis of the processes is given. The second part is devoted to the experimental characterization of both types of porous wastes. The third part deals with the processing of such wastes using an hydraulic binder. The study stresses on both on the stabilization/solidification efficiency of the process and on the conditions of its implementation. The same work is made for a process that uses a bituminous binder. Some choice criteria for the selection of the better process are deduced from the examination of the overall data collected. The waste characterization methodology is applied six times: two times for the raw wastes, two times for the same wastes processed with an hydraulic binder, and two times for the same wastes processed with a bituminous binder. (J.S.)

  19. Frost resistance of concrete with crushed brick as aggregate

    Janković Ksenija; Bojović Dragan; Nikolić Dragan; Lončar Ljiljana; Romakov Zoran

    2010-01-01

    The investigation included concrete made by using recycled brick as aggregate. Experimental work included several types of concrete made with the same cement content (385 kg/m3), and same consistency (slump about 1 cm). Recycled brick and combination of natural river aggregate and recycled brick were used as aggregates. The influence of percentage and grain size of crushed brick aggregate on concrete compressive strength, water absorption and frost resistance were observed. On the basis of th...

  20. Revisiting Aggregation for Data Intensive Applications: A Performance Study

    Wen, Jian; Borkar, Vinayak R.; Carey, Michael J.; Tsotras, Vassilis J.

    2013-01-01

    Aggregation has been an important operation since the early days of relational databases. Today's Big Data applications bring further challenges when processing aggregation queries, demanding adaptive aggregation algorithms that can process large volumes of data relative to a potentially limited memory budget (especially in multiuser settings). Despite its importance, the design and evaluation of aggregation algorithms has not received the same attention that other basic operators, such as jo...