Statistical Estimation of Subgrade Reaction Coefficient For Horizontally Loaded Piles
International Nuclear Information System (INIS)
Honjo, Yusuke; Zaika, Yulvi; Pokharel, Gyaneswor
2002-01-01
Appropriate horizontal subgrade reaction (k h ) is required to evaluate stress and displacement in horizontal loading pile. In order to obtain more accurate prediction of pile behavior, statistical analysis is employed. Based on 21 data set gathered on horizontal loading piles, inverse analysis and regression analysis are carried out. The main value and uncertainty are obtained by inverse analysis, could be employed in the regression analysis. The relationship between the lateral resistant constant (k c ) and SPT N value takes into account in correlated and uncorrelated condition. The results are compared with Port and Harbor Technical Research Institute (JPHA, 1999) and Japan Highway Bridge Specification IV (JRA, 1996). The computed values are found to be very close to the JPHA line and within the range of JRA lines in diameter 0.5 m and 2 m
Modulus of Subgrade Reaction and Deflection
Directory of Open Access Journals (Sweden)
Austin Potts
2009-01-01
Full Text Available Differential equations govern the bending and deflection of roads under a concentrated load. Identifying critical parameters, such as the maximum deflection and maximum bending moments of a street supported by an elastic subgrade, is key to designing safe and reliable roadways. This project solves the underlying differential equation in pavement deflection and tests various parameters to highlight the importance in selecting proper foundation materials.
Directory of Open Access Journals (Sweden)
Ray Richard Paul
2015-09-01
Full Text Available Geotechnical and structural engineers are faced with a difficult task when their designs interact with each other. For complex projects, this is more the norm than the exception. In order to help bridge that gap, a method for modeling the behavior of a foundation using a simple elasto-plastic subgrade reaction was developed. The method uses an optimization technique to position 4-6 springs along a pile foundation to produce similar load deflection characteristics that were modeled by more sophisticated geotechnical finite element software. The methodology uses an Excel spreadsheet for accepting user input and delivering an optimized subgrade spring stiffness, yield, and position along the pile. In this way, the behavior developed from the geotechnical software can be transferred to the structural analysis software. The optimization is achieved through the solver add-in within Excel. Additionally, a beam on a nonlinear elastic foundation model is used to compute deflections of the optimized subgrade reaction configuration.
Winkler's single-parameter subgrade model from the perspective of ...
African Journals Online (AJOL)
... tensor are taken into consideration, whereas the shear stresses are intentionally dropped with the purpose of providing a useful perspective, with which Winkler's model and its associated coefficient of subgrade reaction can be viewed. The formulation takes into account the variation of the elasticity modulus with depth.
SIMULATION OF SUBGRADE EMBANKMENT ON WEAK BASE
Directory of Open Access Journals (Sweden)
V. D. Petrenko
2015-08-01
Full Text Available Purpose. This article provides: the question of the sustainability of the subgrade on a weak base is considered in the paper. It is proposed to use the method of jet grouting. Investigation of the possibility of a weak base has an effect on the overall deformation of the subgrade; the identification and optimization of the parameters of subgrade based on studies using numerical simulation. Methodology. The theoretical studies of the stress-strain state of the base and subgrade embankment by modeling in the software package LIRA have been conducted to achieve this goal. Findings. After making the necessary calculations perform building fields of a subsidence, borders cramped thickness, bed’s coefficients of Pasternak and Winkler. The diagrams construction of vertical stress performs at any point of load application. Also, using the software system may perform peer review subsidence, rolls railroad tracks in natural and consolidated basis. Originality. For weak soils is the most appropriate nonlinear model of the base with the existing areas of both elastic and limit equilibrium, mixed problem of the theory of elasticity and plasticity. Practical value. By increasing the load on the weak base as a result of the second track construction, adds embankment or increasing axial load when changing the rolling stock process of sedimentation and consolidation may continue again. Therefore, one of the feasible and promising options for the design and reconstruction of embankments on weak bases is to strengthen the bases with the help of jet grouting. With the expansion of the railway infrastructure, increasing speed and weight of the rolling stock is necessary to ensure the stability of the subgrade on weak bases. LIRA software package allows you to perform all the necessary calculations for the selection of a proper way of strengthening weak bases.
Performance evaluation of subgrade stabilization with recycled materials.
2016-02-29
Due to rising costs of good quality acceptable materials for remove/replace options and traditional : subgrade stabilization materials, MDOT is in need to identify potential recycled materials to treat : unacceptable subgrade soils. Use of recycled m...
Improvement of strength characteristics of lateritic sub-grade soil ...
African Journals Online (AJOL)
Journal of Applied Sciences and Environmental Management ... Abstract. This paper presents the results of investigation of the behavior of pavement subgrade soil stabilized with shredded polyethylene waste. ... Keywords: Lateritic soil, High density polyethylene (HDPE) waste, Pavement thickness, Sub-grade soil ...
Long-Term benefits of stabilizing soil subgrades.
2002-06-01
The main intent of this study was an attempt to address questions concerning bearing strengths, longevity, durability, structural credit, economics, and performance of pavements resting on soil subgrades mixed with chemical admixtures. In-depth field...
Comparative analysis of calculation models of railway subgrade
Directory of Open Access Journals (Sweden)
I.O. Sviatko
2013-08-01
Full Text Available Purpose. In transport engineering structures design, the primary task is to determine the parameters of foundation soil and nuances of its work under loads. It is very important to determine the parameters of shear resistance and the parameters, determining the development of deep deformations in foundation soils, while calculating the soil subgrade - upper track structure interaction. Search for generalized numerical modeling methods of embankment foundation soil work that include not only the analysis of the foundation stress state but also of its deformed one. Methodology. The analysis of existing modern and classical methods of numerical simulation of soil samples under static load was made. Findings. According to traditional methods of analysis of ground masses work, limitation and the qualitative estimation of subgrade deformations is possible only indirectly, through the estimation of stress and comparison of received values with the boundary ones. Originality. A new computational model was proposed in which it will be applied not only classical approach analysis of the soil subgrade stress state, but deformed state will be also taken into account. Practical value. The analysis showed that for accurate analysis of ground masses work it is necessary to develop a generalized methodology for analyzing of the rolling stock - railway subgrade interaction, which will use not only the classical approach of analyzing the soil subgrade stress state, but also take into account its deformed one.
The Influence of Particle Charge on Heterogeneous Reaction Rate Coefficients
Aikin, A. C.; Pesnell, W. D.
2000-01-01
The effects of particle charge on heterogeneous reaction rates are presented. Many atmospheric particles, whether liquid or solid are charged. This surface charge causes a redistribution of charge within a liquid particle and as a consequence a perturbation in the gaseous uptake coefficient. The amount of perturbation is proportional to the external potential and the square of the ratio of debye length in the liquid to the particle radius. Previous modeling has shown how surface charge affects the uptake coefficient of charged aerosols. This effect is now included in the heterogeneous reaction rate of an aerosol ensemble. Extension of this analysis to ice particles will be discussed and examples presented.
Evaluation of Subgrade Soils using California Bearing Ratio (Cbr) in ...
African Journals Online (AJOL)
The two options that are fit for the upgrade are the over – excavation and stabilization options. The over - excavation method of enhancement of the performance of the subgrade materials that have been studied will require the excavation of the sub- grade soil to the depth of 0.7m and the subsequent replacement with ...
Improvement of poor subgrade soils using cement kiln dust
Directory of Open Access Journals (Sweden)
Ahmed Mancy Mosa
2017-12-01
Full Text Available Construction of pavements layers on subgrade with excellent to good properties reduces the thickness of the layers and consequently reduces the initial and maintenance cost of highways and vice versa. However, construction of pavements on poor subgrade is unavoidable due to several constrains. Improvement of subgrade properties using traditional additives such as lime and Portland cement adds supplementary costs. Therefore, using by-products in this domain involves technical, economic, and environmental advantages. Cement kiln dust (CKD is generated in huge quantities as a by-product material in Portland cement plants. Therefore, it can be considered as an excellent alternative in this domain. In Iraq, Portland cement plants generate about 350000 tons of CKD annually which is available for free. Therefore, Iraq can be adopted as a case study. This paper covers using CKD to improve the properties of poor subgrade soils based on series of California Bearing Ration (CBR tests on sets of untreated samples and samples treated with different doses of CKD in combination with different curing periods to investigate their effects on soil properties. The results exhibited that adding 20% of CKD with curing for 14 days increases the CBR value from 3.4% for untreated soil to 48% for treated soil; it, also, decreases the swelling ratio. To determine the effects of using this dose under the mentioned curing period on the designed thicknesses of pavements layers, a case study was adopted. The case study results exhibited that treatment of the subgrade soil by 20% of CKD with curing for 14 days reduces the cost of the pavements by $25.875 per square meter.
Design and performance of subgrade biogeochemical reactors.
Gamlin, Jeff; Downey, Doug; Shearer, Brad; Favara, Paul
2017-12-15
Subgrade biogeochemical reactors (SBGRs), also commonly referred to as in situ bioreactors, are a unique technology for treatment of contaminant source areas and groundwater plume hot spots. SBGRs have most commonly been configured for enhanced reductive dechlorination (ERD) applications for chlorinated solvent treatment. However, they have also been designed for other contaminant classes using alternative treatment media. The SBGR technology typically consists of removal of contaminated soil via excavation or large-diameter augers, and backfill of the soil void with gravel and treatment amendments tailored to the target contaminant(s). In most cases SBGRs include installation of infiltration piping and a low-flow pumping system (typically solar-powered) to recirculate contaminated groundwater through the SBGR for treatment. SBGRs have been constructed in multiple configurations, including designs capable of meeting limited access restrictions at heavily industrialized sites, and at sites with restrictions on surface disturbance due to sensitive species or habitat issues. Typical performance results for ERD applications include 85 to 90 percent total molar reduction of chlorinated volatile organic compounds (CVOCs) near the SBGR and rapid clean-up of adjacent dissolved contaminant source areas. Based on a review of the literature and CH2M's field-scale results from over a dozen SBGRs with a least one year of performance data, important site-specific design considerations include: 1) hydraulic residence time should be long enough for sufficient treatment but not too long to create depressed pH and stagnant conditions (e.g., typically between 10 and 60 days), 2) reactor material should balance appropriate organic mulch as optimal bacterial growth media along with other organic additives that provide bioavailable organic carbon, 3) a variety of native bacteria are important to the treatment process, and 4) biologically mediated generation of iron sulfides along with
Rate coefficients for hydrogen abstraction reaction of pinonaldehyde
Indian Academy of Sciences (India)
The H abstraction reaction from the –CHO group was found to be the most dominant reaction channelamong all the possible reaction pathways and its corresponding rate coefficient at 300 K is kEckart's unsymmetrical= 3.86 ×10-10 cm3 molecule-1 s-1. Whereas the channel with immediate lower activation energy is the ...
ESTIMATION OF SUBGRADE STRENGTHENING INFLUENCE USING SOILCEMENT ELEMENTS
Directory of Open Access Journals (Sweden)
V. D. Petrenko
2016-08-01
Full Text Available Purpose. The aim of this work is to identify dependencies and options to strengthen the roadbed and a weak base by grouting piles. Analysis of software package SCAD to assess the effect of the selected option of strengthening the construction of spatial subgrade models. Methodology. In this paper the method of calculation of the soil mass in the software package SCAD is considered, which is a universal accounting system of finite-element analysis of structures and is focused on solving problems of designing buildings and structures rather complex structure. The finite element method is among the most modern and effective methods for the calculation of structures for various purposes. In the simulation, we get a complete picture of the stress-strain state of the study area, as well as the value of the limit load, rainfall, and so on. The spatial model based on the finite element volume, to better address the real characteristics of the soil mass, meets all the geometric characteristics of size and natural subgrade and the top structure the path that has been adopted in Ukraine. Findings. It was found that the most effective option to strengthen the roadbed, when applying grouting piles at the base of the subgrade and body, is to strengthen the five piles. At the same time there is even strengthen the soil mass at the level of 25 … 30% of the entire depth. However, even with the strengthening of the only two piles at the base of the effect of the strengthening of 14.1%. Established equation is linear and describes the decrease in strain. Taking into account the results of the research can be concluded that the consolidation is proportional to the depth with any number of piles. The dependence of the strain on the number of piles adheres to a polynomial function. Strengthening the bases of the subgrade and body depth also occurs in proportion with any number of piles. Originality. Design scheme generation algorithm for the calculation of the
Directory of Open Access Journals (Sweden)
Liu Jie
2013-01-01
Full Text Available Groundwater is a main natural factor impacting the subgrade structure, and it plays a significant role in the stability of the subgrade. In this paper, the analytical solution of the subgrade moisture variations considering groundwater fluctuations is derived based on Richards’ equation. Laboratory subgrade model is built, and three working cases are performed in the model to study the capillary action of groundwater at different water tables. Two types of antidrainage materials are employed in the subgrade model, and their anti-drainage effects are discussed. Moreover, numerical calculation is conducted on the basis of subgrade model, and the calculate results are compared with the experimental measurements. The study results are shown. The agreement between the numerical and the experimental results is good. Capillary action is obvious when the groundwater table is rising. As the groundwater table is falling, the moisture decreases in the position of the subgrade near the water table and has no variations in the subgrade where far above the table. The anti-drainage effect of the sand cushion is associated with its thickness and material properties. New waterproofing and drainage material can prevent groundwater entering the subgrade effectively, and its anti-drainage effect is good.
2009-06-01
A comprehensive laboratory study was undertaken to determine engineering properties of cementitiously stabilized common subgrade soils in Oklahoma for the design of roadway pavements in accordance with the AASHTO 2002 Mechanistic-Empirical Pavement D...
Field Verification of Undercut Criteria and Alternatives for Subgrade Stabilization-Coastal Plain
2012-06-01
The North Carolina Department of Transportation (NCDOT) is progressing toward developing quantitative and systematic : criteria that address the implementation of undercutting as a subgrade stabilization measure. As part of this effort, a : laborator...
Pavement Subgrade Performance Study
DEFF Research Database (Denmark)
Zhang, Wei; Ullidtz, Per; Macdonald, Robin
1998-01-01
The report describes the second test in the Danish Road Testing Machine (RTM) under the International Pavement Subgrade Performance Study. Pavement response was measured in different layers, and compared to different theroretical values. Performance in terms of plastic strains, rutting...
Evaluation of Carbonation Effects on Cement-Solidified Contaminated Soil Used in Road Subgrade
Directory of Open Access Journals (Sweden)
Yundong Zhou
2018-01-01
Full Text Available Cement solidification/stabilization is widely used towards contaminated soil since it has a low price and significant improvement for the structural capacity of soil. To increase the usage of the solidified matrix, cement-solidified contaminated soil was used as road subgrade material. In this study, carbonation effect that reflected the durability on strength characteristics of cement-solidified contaminated soil and the settlement of pavement were evaluated through experimental and numerical analysis, respectively. According to results, compressive strengths of specimens with 1% Pb(II under carbonation and standard curing range from 0.44 MPa to 1.17 MPa and 0.14 MPa to 2.67 MPa, respectively. The relatively low strengths were attributed to immobilization of heavy metal, which consumed part of SiO2, Al2O3, and CaO components in the cement or kaolin and reduced the hydration and pozzolanic reaction materials. This phenomenon further decreased the strength of solidified soils. The carbonation depth of 1% Cu(II or Zn(II contaminated soils was 18 mm, which significantly increased with the increase of curing time and contamination concentration. Furthermore, the finite element calculation results showed that surface settlements decreased with the increase of modulus of subgrade and the distance away from the center. At the center, the pavement settlement was proportional to the level of traffic load.
Instability improvement of the subgrade soils by lime addition at Borg El-Arab, Alexandria, Egypt
El Shinawi, A.
2017-06-01
Subgrade soils can affect the stability of any construction elsewhere, instability problems were found at Borg El-Arab, Alexandria, Egypt. This paper investigates geoengineering properties of lime treated subgrade soils at Borg El-Arab. Basic laboratory tests, such as water content, wet and dry density, grain size, specific gravity and Atterberg limits, were performed for twenty-five samples. Moisture-density (compaction); California Bearing Ratio (CBR) and Unconfined Compression Strength (UCS) were conducted on treated and natural soils. The measured geotechnical parameters of the treated soil shows that 6% lime is good enough to stabilize the subgrade soils. It was found that by adding lime, samples shifted to coarser side, Atterberg limits values of the treated soil samples decreased and this will improve the soil to be more stable. On the other hand, Subgrade soils improved as a result of the bonding fine particles, cemented together to form larger size and reduce the plastiCity index which increase soils strength. The environmental scanning electron microscope (ESEM) is point to the presence of innovative aggregated cement materials which reduce the porosity and increase the strength as a long-term curing. Consequently, the mixture of soil with the lime has acceptable mechanical characteristics where, it composed of a high strength base or sub-base materials and this mixture considered as subgrade soil for stabilizations and mitigation the instability problems that found at Borg Al-Arab, Egypt.
Effect of Cement Replacement with Carbide Waste on the Strength of Stabilized Clay Subgrade
Directory of Open Access Journals (Sweden)
Muntohar A.S.
2016-03-01
Full Text Available Cement is commonly used for soil stabilization and many other ground improvement techniques. Cement is believed to be very good to improve the compressive and split-tensile strength of clay subgrades. In some application cement could be partly or fully replaced with carbide waste. This research is to study the effectiveness of the cement replacement and to find the maximum carbide waste content to be allowed for a clay subgrade. The quantities of cement replaced with the carbide waste were 30, 50, 70, 90, and 100% by its mass. The results show that replacing the cement with carbide waste decreased both the compressive and split tensile strength. Replacing cement content with carbide waste reduced its ability for stabilization. The carbide waste content should be less than 70% of the cement to provide a sufficient stabilizing effect on a clay subgrade.
The rate coefficients of unimolecular reactions in the systems with power-law distributions
Yin, Cangtao; Guo, Ran; Du, Jiulin
2014-08-01
The rate coefficient formulae of unimolecular reactions are generalized to the systems with the power-law distributions based on nonextensive statistics, and the power-law rate coefficients are derived in the high and low pressure limits, respectively. The numerical analyses are made of the rate coefficients as functions of the ν-parameter, the threshold energy, the temperature and the number of degrees of freedom. We show that the new rate coefficients depend strongly on the ν-parameter different from one (thus from a Boltzmann-Gibbs distribution). Two unimolecular reactions, CH3CO→CH3+CO and CH3NC→CH3CN, are taken as application examples to calculate their power-law rate coefficients, which obtained with the ν-parameters slightly different from one can be exactly in agreement with all the experimental studies on these two reactions in the given temperature ranges.
Mechanical behavior of embankments overlying on loose subgrade stabilized by deep mixed columns
Directory of Open Access Journals (Sweden)
Morteza Esmaeili
2016-10-01
Full Text Available Deep mixed column (DMC is known as one of the effective methods for stabilizing the natural earth beneath road or railway embankments to control stability and settlements under traffic loads. The load distribution mechanism of embankment overlying on loose subgrades stabilized with DMCs considerably depends on the columns' mechanical and geometrical specifications. The present study uses the laboratory investigation to understand the behavior of embankments lying on loose sandy subgrade in three different conditions: (1 subgrade without reinforcement, (2 subgrade reinforced with DMCs in a triangular pattern and horizontal plan, and (3 subgrade reinforced with DMCs in a square pattern and horizontal plan. For this purpose, by adopting the scale factor of 1:10, a reference embankment with 20 cm height, 250 cm length, and 93% maximum dry density achieved in standard Proctor compaction test was constructed over a 70 cm thick loose sandy bed with the relative density of 50% in a loading chamber, and its load-displacement behavior was evaluated until the failure occurred. In the next two tests, DMCs (with 10 cm diameter, 40 cm length, and 25 cm center-to-center spacing were placed in groups in two different patterns (square and triangular in the same sandy bed beneath the embankment and, consequently, the embankments were constructed over the reinforced subgrades and gradually loaded until the failure happened. In all the three tests, the load-displacement behaviors of the embankment and the selected DMCs were instrumented for monitoring purpose. The obtained results implied 64% increase in failure load and 40% decrease in embankment crest settlement when using the square pattern of DMCs compared with those of the reference embankment, while these values were 63% and 12%, respectively, for DMCs in triangular pattern. This confirmed generally better performance of DMCs with a triangular pattern.
Rate Coefficient Measurements of the Reaction CH3 + O2 = CH3O + O
Hwang, S. M.; Ryu, Si-Ok; DeWitt, K. J.; Rabinowitz, M. J.
1999-01-01
Rate coefficients for the reaction CH3 + O2 = CH3O + O were measured behind reflected shock waves in a series of lean CH4-O2-Ar mixtures using hydroxyl and methyl radical diagnostics. The rate coefficients are well represented by an Arrhenius expression given as k = (1.60(sup +0.67, sub -0.47 ) x 10(exp 13) e(-15813 +/- 587 K/T)/cubic cm.mol.s. This expression, which is valid in the temperature range 1575-1822 K, supports the downward trend in the rate coefficients that has been reported in recent determinations. All measurements to date, including the present study, have been to some extent affected by secondary reactions. The complications due to secondary reactions, choice of thermochemical data, and shock-boundary layer interactions that affect the determination of the rate coefficients are examined.
Rate Coefficient Measurements of the Reaction CH3+O2+CH3O+O
Hwang, S. M.; Ryu, Si-Ok; DeWitt, K. J.; Rabinowitz, M. J.
1999-01-01
Rate coefficients for the reaction CH3 + O2 = CH3O + O were measured behind reflected shock waves in a series of lean CH4-O2-Ar mixtures using hydroxyl and methyl radical diagnostics. The rate coefficients are well represented by an Arrhenius expression given as k = (1.60(sup +0.67, -0.47)) X 10(exp 13) exp(- 15813 +/- 587 K/T)cc/mol s. This expression, which is valid in the temperature range 1575-1822 K, supports the downward trend in the rate coefficients that has been reported in recent determinations. All measurements to date, including the present study, have been to some extent affected by secondary reactions. The complications due to secondary reactions, choice of thermochemical data, and shock-boundary layer interactions that affect the determination of the rate coefficients are examined.
Development of a fiber optic pavement subgrade strain measurement system
Miller, Craig Emerson
2000-11-01
This dissertation describes the development of a fiber optic sensing system to measure strains within the soil subgrade of highway pavements resulting from traffic loads. The motivation to develop such a device include improvements to: (1)all phases of pavement design, (2)theoretical models used to predict pavement performance, and (3)pavement rehabilitation. The design of the sensing system encompasses selecting an appropriate transducer design as well as the development of optimal optical and demodulation systems. The first is spring based, which attempts to match its spring stiffness to that of the soil-data indicate it is not an optimal transducer design. The second transducer implements anchoring plates attached to two telescoping tubes which allows the soil to be compacted to a desired density between the plates to dictate the transducer's behavior. Both transducers include an extrinsic Fabry- Perot cavity to impose the soil strains onto a phase change of the optical signal propagating through the cavity. The optical system includes a low coherence source and allows phase modulation via path length stretching by adding a second interferometer in series with the transducer, resulting in a path matched differential interferometer. A digitally implemented synthetic heterodyne demodulator based on a four step phase stepping algorithm is used to obtain unambiguous soil strain information from the displacement of the Fabry-Perot cavity. The demodulator is calibrated and characterized by illuminating the transducer with a second long coherence source of different wavelength. The transducer using anchoring plates is embedded within cylindrical soil specimens of varying soil types and soil moisture contents. Loads are applied to the specimen and resulting strains are measured using the embedded fiber optic gage and LVDTs attached to the surface of the specimen. This experimental verification is substantiated using a finite element analysis to predict any differences
Temperature-Dependent Rate Coefficients for the Reaction of CH2OO with Hydrogen Sulfide.
Smith, Mica C; Chao, Wen; Kumar, Manoj; Francisco, Joseph S; Takahashi, Kaito; Lin, Jim Jr-Min
2017-02-09
The reaction of the simplest Criegee intermediate CH 2 OO with hydrogen sulfide was measured with transient UV absorption spectroscopy in a temperature-controlled flow reactor, and bimolecular rate coefficients were obtained from 278 to 318 K and from 100 to 500 Torr. The average rate coefficient at 298 K and 100 Torr was (1.7 ± 0.2) × 10 -13 cm 3 s -1 . The reaction was found to be independent of pressure and exhibited a weak negative temperature dependence. Ab initio quantum chemistry calculations of the temperature-dependent reaction rate coefficient at the QCISD(T)/CBS level are in reasonable agreement with the experiment. The reaction of CH 2 OO with H 2 S is 2-3 orders of magnitude faster than the reaction with H 2 O monomer. Though rates of CH 2 OO scavenging by water vapor under atmospheric conditions are primarily controlled by the reaction with water dimer, the H 2 S loss pathway will be dominated by the reaction with monomer. The agreement between experiment and theory for the CH 2 OO + H 2 S reaction lends credence to theoretical descriptions of other Criegee intermediate reactions that cannot easily be probed experimentally.
van Noorden, C. J.; Jonges, G. N.
1992-01-01
Molar extinction coefficients of precipitated lead sulfide (PbS) and polymerized diaminobenzidine (polyDAB) have been determined at wavelengths of 450 nm and 480 nm, respectively, for quantitative histochemical analysis of phosphatase reactions. These values are essential for the conversion of
2002-06-01
The objective of this study was to investigate the effect of moisture content and dry unit weight on the resilient characteristics of subgrade soil predicted by the cone penetration test. An experimental program was conducted in which cone penetratio...
International Nuclear Information System (INIS)
Haggerty, R.; Schroth, M.H.; Istok, J.D.
1998-01-01
The single-well, ''''push-pull'''' test method is useful for obtaining information on a wide variety of aquifer physical, chemical, and microbiological characteristics. A push-pull test consists of the pulse-type injection of a prepared test solution into a single monitoring well followed by the extraction of the test solution/ground water mixture from the same well. The test solution contains a conservative tracer and one or more reactants selected to investigate a particular process. During the extraction phase, the concentrations of tracer, reactants, and possible reaction products are measured to obtain breakthrough curves for all solutes. This paper presents a simplified method of data analysis that can be used to estimate a first-order reaction rate coefficient from these breakthrough curves. Rate coefficients are obtained by fitting a regression line to a plot of normalized concentrations versus elapsed time, requiring no knowledge of aquifer porosity, dispersivity, or hydraulic conductivity. A semi-analytical solution to the advective-dispersion equation is derived and used in a sensitivity analysis to evaluate the ability of the simplified method to estimate reaction rate coefficients in simulated push-pull tests in a homogeneous, confined aquifer with a fully-penetrating injection/extraction well and varying porosity, dispersivity, test duration, and reaction rate. A numerical flow and transport code (SUTRA) is used to evaluate the ability of the simplified method to estimate reaction rate coefficients in simulated push-pull tests in a heterogeneous, unconfined aquifer with a partially penetrating well. In all cases the simplified method provides accurate estimates of reaction rate coefficients; estimation errors ranged from 0.1 to 8.9% with most errors less than 5%
Directory of Open Access Journals (Sweden)
Shim S.M.
2012-01-01
Full Text Available The performance of the CO2 absorber column using mono-ethanolamine (MEA solution as chemical solvent are predicted by a One-Dimensional (1-D rate based model in the present study. 1-D Mass and heat balance equations of vapor and liquid phase are coupled with interfacial mass transfer model and vapor-liquid equilibrium model. The two-film theory is used to estimate the mass transfer between the vapor and liquid film. Chemical reactions in MEA-CO2-H2O system are considered to predict the equilibrium pressure of CO2 in the MEA solution. The mathematical and reaction kinetics models used in this work are calculated by using in-house code. The numerical results are validated in the comparison of simulation results with experimental and simulation data given in the literature. The performance of CO2 absorber column is evaluated by the 1-D rate based model using various reaction rate coefficients suggested by various researchers. When the rate of liquid to gas mass flow rate is about 8.3, 6.6, 4.5 and 3.1, the error of CO2 loading and the CO2 removal efficiency using the reaction rate coefficients of Aboudheir et al. is within about 4.9 % and 5.2 %, respectively. Therefore, the reaction rate coefficient suggested by Aboudheir et al. among the various reaction rate coefficients used in this study is appropriate to predict the performance of CO2 absorber column using MEA solution. [Acknowledgement. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF, funded by the Ministry of Education, Science and Technology (2011-0017220].
CSIR Research Space (South Africa)
Theyse, HL
2002-02-01
Full Text Available procedure commonly used in South Africa, namely the South African Mechanistic-Empirical Design Method (SAMDM). This was achieved through the development of a new design approach and permanent deformation model for the pavement subgrade. The new distress...
Microscopic calculation of friction coefficients for use in heavy-ion reaction
International Nuclear Information System (INIS)
Iwamoto, A.; Harada, K.; Yoshida, S.
1981-01-01
A microscopic calculation has been done for the friction coefficient for use in the deep-inelastic collision of heavy nuclei. We adopted the formalism of the linear response theory as a basis and used the adiabatic base of the two-center shell model. Several reaction channels with the total mass numbers of 236 and 260 systems were investigated. The friction coefficients for the radial and deforming motions including the coupling term were calculated as a function of the distance between two nuclei and deformation of the two nuclei for each channel. The general feature of the friction coefficient, its strength and form factor, was clarified in this model and comparison with the results of other models were done. It was found that our model gives a physically plausible value for the friction coefficient as a whole. (orig.)
International Nuclear Information System (INIS)
Janev, R.K.; Kato, T.; Wang, J.G.
2001-05-01
The available experimental and theoretical cross section data on charge exchange processes in collisions of protons with hydrocarbon molecules have been collected and critically assessed. Using well established scaling relationships for the charge exchange cross sections at low and high collision energies, as well as the known rate coefficients for these reactions in the thermal energy region, a complete cross section database is constructed for proton-C x H y charge exchange reactions from thermal energies up to several hundreds keV for all C x H y molecules with x=1, 2, 3 and 1 ≤ y ≤ 2x + 2. Rate coefficients for these charge exchange reactions have also been calculated in the temperature range from 0.1 eV to 20 keV. (author)
Energy Technology Data Exchange (ETDEWEB)
Janev, R.K.; Kato, T. [National Inst. for Fusion Science, Toki, Gifu (Japan); Wang, J.G. [Department of Physics and Astronomy, University of Georgia, Athens (United States)
2001-05-01
The available experimental and theoretical cross section data on charge exchange processes in collisions of protons with hydrocarbon molecules have been collected and critically assessed. Using well established scaling relationships for the charge exchange cross sections at low and high collision energies, as well as the known rate coefficients for these reactions in the thermal energy region, a complete cross section database is constructed for proton-C{sub x}H{sub y} charge exchange reactions from thermal energies up to several hundreds keV for all C{sub x}H{sub y} molecules with x=1, 2, 3 and 1 {<=} y {<=} 2x + 2. Rate coefficients for these charge exchange reactions have also been calculated in the temperature range from 0.1 eV to 20 keV. (author)
Directory of Open Access Journals (Sweden)
Hugo A. Rondón-Quintana
2013-11-01
Full Text Available The mainly factors studied to predict fatigue life of hot mix asphalt-HMA in flexible pavements are the loading effect, type of test, compaction methods, design parameters of HMA (e.g., particle size and size distribution curve, fine content, type of bitumen and the variables associated with the environment (mainly moisture, temperature, aging. This study evaluated through a computer simulation, the influence of the granular layers and subgrade on the fatigue life of asphalt layers in flexible pavement structures. Mechanics parameters of granular layers of subgrade, base and subbase were obtained using the mathematical equations currently used for this purpose in the world. The emphasis of the study was the city of Bogotá, where the average annual temperature is 14°C and soils predominantly clay, generally experience CBR magnitudes between 1% and 4%. General conclusion: stiffness of the granular layers and subgrade significantly affect the fatigue resistance of HMA mixtures. Likewise, the use of different equations reported in reference literature in order to characterize granular layers may vary the fatigue life between 4.6 and 48.5 times, varying the thickness of the pavement layers in the design.
Chemical stabilization of subgrade soil for the strategic expeditionary landing field
Conaway, M. H.
1983-06-01
The Strategic Expeditionary Landing Field (SELF) is a military expeditionary-type airfield with an aluminum matted surface that is designed for sustained tactical and cargo airlift operations in an amphibious objective area. Because of the operational traffic parameters such as loads of the various types of aircraft, tire pressures and volume of traffic, a base layer must be constructed over subgrade soil support conditions which may be only marginal. The base layer could be constructed with conventional soil construction techniques (compaction) and yield the required strength. It would be difficult, however, to maintain this strength for the required one-year service life under many climatic conditions due to the degrading effects of water on the support capacity of many soils. Chemical soil stabilization with lime, portland cement and asphalt stabilizing agents could be used to treat the soil. These additives, when properly mixed with certain types of soils, initiate reactions which will increase soil support strength and enhance durability (resistance to the degrading effects of water). Technically, this procedure is quite viable but logistically, it may not be feasible.
International Nuclear Information System (INIS)
Povar, I.G.
1995-01-01
Equations describing the relation between temperature coefficient of ∂lnα/∂T complexing degree and the sum of changes in the enthalpy of complex formation of the composition M m L n δH mn multiplied by the weight coefficients k mm , are presented. A method to determine changes in the enthalpy of certain ΔH mm reactions from ∂lnα/∂T derivatives has been suggested. The best approximating equation from lnα/(T) dependence has been found. Errors of thus determined δH mm values are estimated and the results of calculation experiment for the system In 3+ -F - are provided. 10 refs., 2 figs., 3 tabs
PLUTONIUM FINISHING PLANT (PFP) SUB-GRADE EE/CA EVALUATION OF ALTERNATIVES: A NEW MODEL
International Nuclear Information System (INIS)
HOPKINS, A.M.
2007-01-01
An engineering evaluation/cost analysis (EE/CA) was performed at the Hanford Site's Plutonium Finishing Plant (PFP). The purpose of the EVCA was to identify the sub-grade items to be evaluated; determine the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) hazardous substances through process history and available data; evaluate these hazards; and as necessary, identify the available alternatives to reduce the risk associated with the contaminants. The sub-grade EWCA considered four alternatives for an interim removal action: (1) No Action; (2) Surveillance and Maintenance (S and M); (3) Stabilize and Leave in Place (Stabilization); and (4) Remove, Treat and Dispose (RTD). Each alternative was evaluated against the CERCLA criteria for effectiveness, implementability, and cost
Experimental Study on the Utilization of Fine Steel Slag on Stabilizing High Plastic Subgrade Soil
Hussien Aldeeky; Omar Al Hattamleh
2017-01-01
The three major steel manufacturing factories in Jordan dump their byproduct, steel slag, randomly in open areas, which causes many environmental hazardous problems. This study intended to explore the effectiveness of using fine steel slag aggregate (FSSA) in improving the geotechnical properties of high plastic subgrade soil. First soil and fine steel slag mechanical and engineering properties were evaluating. Then 0%, 5%, 10%, 15%, 20%, and 25% dry weight of soil of fine steel slag (FSSA) w...
Evaluation of AM2 2 1 Lay Pattern Over a 25 CBR Subgrade
2018-04-30
Geotechnical and Structures Laboratory U.S. Army Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS 39180-6199 Final...which no subgrade maintenance is required during expeditionary operations. Recent investigations showed that the 2-1 configuration significantly... maintenance requirements for F-15E and C-17 operations. DISCLAIMER: The contents of this report are not to be used for advertising, publication
The estimation of parameter compaction values for pavement subgrade stabilized with lime
Lubis, A. S.; Muis, Z. A.; Simbolon, C. A.
2018-02-01
The type of soil material, field control, maintenance and availability of funds are several factors that must be considered in compaction of the pavement subgrade. In determining the compaction parameters in laboratory desperately requires considerable materials, time and funds, and reliable laboratory operators. If the result of soil classification values can be used to estimate the compaction parameters of a subgrade material, so it would save time, energy, materials and cost on the execution of this work. This is also a clarification (cross check) of the work that has been done by technicians in the laboratory. The study aims to estimate the compaction parameter values ie. maximum dry unit weight (γdmax) and optimum water content (Wopt) of the soil subgrade that stabilized with lime. The tests that conducted in the laboratory of soil mechanics were to determine the index properties (Fines and Liquid Limit/LL) and Standard Compaction Test. Soil samples that have Plasticity Index (PI) > 10% were made with additional 3% lime for 30 samples. By using the Goswami equation, the compaction parameter values can be estimated by equation γd max # = -0,1686 Log G + 1,8434 and Wopt # = 2,9178 log G + 17,086. From the validation calculation, there was a significant positive correlation between the compaction parameter values laboratory and the compaction parameter values estimated, with a 95% confidence interval as a strong relationship.
Energy Technology Data Exchange (ETDEWEB)
Clayton, R.K.; Clayton, B.J.
1978-01-01
Reaction centers have been purified from chromatophores of Rhodopseudomonas viridis by treatment with lauryl dimethyl amine oxide followed by hydroxyapatite chromatography and precipitation with ammonium sulfate. The absorption spectrum at low temperature shows bands at 531 and 543 nm, assigned to two molecules of bacteriopheophytin b. The 600 nm band of bacteriochlorophyll b is resolved at low temperature into components at 601 and 606.5 nm. At room temperature the light-induced difference spectrum shows a negative band centered at 615 nm, where the absorption spectrum shows only a week shoulder adjacent to the 600 nm band. The fluorescence spectrum shows a band at 1000 nm and no fluorescence corresponding to the 830 nm absorption band. Two molecules of cytochrome 558 and three of cytochrome 552 accompany each reaction center. The differential extinction coefficient (reduced minus oxidized) of cytochrome 558 nm was estimated as 20 +- 2 mM/sup -1/.cm/sup -1/ through a coupled reaction with equine cytochrome c. The extinction coefficient of reaction centers at 960 nm was determined to be 123 +- 25 mM/sup -1/.cm/sup -1/ by measuring the light-induced bleaching of P-960 and the coupled oxidation of cytochrome 558. The corresponding extinction coefficient at 830 nm is 300 +- 65 mM/sup -1/.cm/sup -1/. The absorbance ratio ..cap alpha../sub 280nm/..cap alpha../sub 830nm/ in our preparations was 2.1, and there was 190 kg protein per mol of reaction centers. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed three major components of apparent molecular weights 31,000, 37,000, and 41,000.
Lime Kiln Dust for Treated Subgrades : Final Report
2017-11-01
Chemical and cementitious materials are often used to modify and stabilize the subgrade soils that serve as foundations for pavements. Improvement of the subgrade provides a better working platform for construction of the layers above and improves th...
Lime Kiln Dust for Treated Subgrades : Technical Summary
2017-11-01
Chemical and cementitious materials are often used to modify and stabilize the subgrade soils that serve as foundations for pavements. Improvement of the subgrade provides a better working platform for construction of the layers above and improves th...
Rate coefficients for the reactions of ions with polar molecules at interstellar temperatures
International Nuclear Information System (INIS)
Adams, N.G.; Smith, D.; Clary, D.C.
1985-01-01
A theory has been developed recently which predicts that the rate coefficients, k, for the reactions of ions with polar molecules at low temperatures will be much greater than the canonical value of 10 -9 cm 3 s -1 . The new theory indicates that k is greatest for low-lying rotational sates and increases rapidly with decreasing temperature. We refer to recent laboratory measurements which validate the theory, present calculated values of k for the reactions of H + 3 ions with several polar molecules, and discuss their significance to interstellar chemistry. For the reactions of ions with molecules having large dipole moments, we recommend that k values as large as 10 -7 cm 3 s -1 should be used in ion-chemical models of low-temperature interstellar clouds
Reaction rate calculations via transmission coefficients
International Nuclear Information System (INIS)
Feit, M.D.; Alder, B.J.
1985-01-01
The transmission coefficient of a wavepacket traversing a potential barrier can be determined by steady state calculations carried out in imaginary time instead of by real time dynamical calculations. The general argument is verified for the Eckart barrier potential by a comparison of transmission coefficients calculated from real and imaginary time solutions of the Schroedinger equation. The correspondence demonstrated here allows a formulation for the reaction rate that avoids difficulties due to both rare events and explicitly time dependent calculations. 5 refs., 2 figs
Kustova, E. V.; Savelev, A. S.; Kunova, O. V.
2018-05-01
Theoretical models for the vibrational state-resolved Zeldovich reaction are assessed by comparison with the results of quasi-classical trajectory (QCT) calculations. An error in the model of Aliat is corrected; the model is generalized taking into account NO vibrational states. The proposed model is fairly simple and can be easily implemented to the software for non-equilibrium flow modeling. It provides a good agreement with the QCT rate coefficients in the whole range of temperatures and reagent/product vibrational states. The developed models are tested in simulations of vibrational and chemical relaxation of air mixture behind a shock wave. The importance of accounting for excitated NO vibrational states and accurate prediction of Zeldovich reactions rates is shown.
Rate coefficient for the reaction N + NO
Fox, J. L.
1994-01-01
Evidence has been advanced that the rate coefficient for the reaction N + NO right arrow N2 + O has a small positive temperature dependence at the high temperatures (900 to 1500 K) that prevail in the terrestrial middle and upper thermosphere by Siskind and Rusch (1992), and at the low temperatures (100 to 200 K) of the Martian lower thermosphere by Fox (1993). Assuming that the rate coefficient recommended by the Jet Propulsion Laboratory evaluation (DeMore et al., 1992) is accurate at 300 K, we derive here the low temperature value of the activation energy for this reaction and thus the rate coefficient that best fits the Viking 1 measured NO densities. We find that the fit is acceptable for a rate coefficient of about 1.3 x 10(exp -10)(T/300)(exp 0.5)exp(-400/T) and better for a value of about 2.5 x 10(exp -10)(T/300)(exp 0.5)exp(-600/T)cu cm/s.
Ilori, Abidemi Olujide
2016-01-01
This study concerned a stretch of 17 km of a 94-km highway alignment in Southeastern Nigeria that has a high incidence of pavement failure arising from subgrade failure. The subgrade of this section of the roadway is composed of Ekenkpon shale, New Netim marl, and Nkporo shale. Under the Unified Soil Classification System, the shales classify as OH (organic clay) and the marl classifies as MH (inorganic silt). Under the American Association of State and Transportation Officials (AASHTO) M 145 soil classification, all these soils classify as A-7-5 soil. Using the AASHTO M 145 group index, none of these soils was considered suitable as subgrade in its native form. Therefore, cement was investigated as a stabilizing agent. Testing demonstrated that 7, 3 and 12 % by weight were the optimum cement contents to reinforce the Ekenkpon shale, New Netim marl, and Nkporo shale, respectively.
Ground reaction force analysed with correlation coefficient matrix in group of stroke patients.
Szczerbik, Ewa; Krawczyk, Maciej; Syczewska, Małgorzata
2014-01-01
Stroke is the third cause of death in contemporary society and causes many disorders. Clinical scales, ground reaction force (GRF) and objective gait analysis are used for assessment of patient's rehabilitation progress during treatment. The goal of this paper is to assess whether signal correlation coefficient matrix applied to GRF can be used for evaluation of the status of post-stroke patients. A group of patients underwent clinical assessment and instrumented gait analysis simultaneously three times. The difference between components of patient's GRF (vertical, fore/aft, med/lat) and normal ones (reference GRF of healthy subjects) was calculated as correlation coefficient. Patients were divided into two groups ("worse" and "better") based on the clinical functional scale tests done at the beginning of rehabilitation process. The results obtained by these two groups were compared using statistical analysis. An increase of median value of correlation coefficient is observed in all components of GRF, but only in non-paretic leg. Analysis of GRF signal can be helpful in assessment of post-stroke patients during rehabilitation. Improvement in stroke patients was observed in non-paretic leg of the "worse" group. GRF analysis should not be the only tool for objective validation of patient's improvement, but could be used as additional source of information.
International Nuclear Information System (INIS)
Imre, K.; Odian, G.
1979-01-01
The effect of diffusion on radiation-initiated graft polymerization has been studied with emphasis on the single- and two-penetrant cases. When the physical properties of the penetrants are similar, the two-penetrant problems can be reduced to the single-penetrant problem by redefining the characteristic parameters of the system. The diffusion-free graft polymerization rate is assumed to be proportional to the upsilon power of the monomer concentration respectively, and, in which the proportionality constant a = k/sub p/R/sub i//sup w//k/sub t//sup z/, where k/sub p/ and k/sub t/ are the propagation and termination rate constants, respectively, and R/sub i/ is the initiation rate. The values of upsilon, w, and z depend on the particular reaction system. The results of earlier work were generalized by allowing a non-Fickian diffusion rate which predicts an essentially exponential dependence on the monomer concentration of the diffusion coefficient, D = D 0 [exp(deltaC/M)], where M is the saturation concentration. A reaction system is characterized by the three dimensionless parameters, upsilon, delta, and A = (L/2)[aM/sup (upsilon--1)//D 0 ]/sup 1/2/, where L is the polymer film thickness. Graft polymerization tends to become diffusion controlled as A increases. Larger values of delta and ν cause a reaction system to behave closer to the diffusion-free regime. Transition from diffusion-free to diffusion-controlled reaction involves changes in the dependence of the reaction rate on film thickness, initiation rate, and monomer concentration. Although the diffusion-free rate is w order in initiation rate, upsilon order in monomer, and independent of film thickness, the diffusion-controlled rate is w/2 order in initiator rate and inverse first-order in film thickness. Dependence of the diffusion-controlled rate on monomer is dependent in a complex manner on the diffusional characteristics of the reaction system. 11 figures, 4 tables
International Nuclear Information System (INIS)
Khan, A.H.
2016-01-01
Highways are amongst the most costly resources contributing directly to the growth of any Country's economy. Subgrade soils as component of highways deteriorate normally from numerous factors resulting into flushing or excessive settlements of embankment involving huge maintenance costs. In this research, an attempt has been made to evaluate suitable technique for stabilization of commonly available subgrade soils of Pakistan based on cost effectiveness and ease in construction. The soils identified as A-3(0) by American Association of State Highway and Transportation Officials (AASHTO) criteria has been stabilized with conventional additives i.e. cement and bitumen in this research. The optimum content of each additive for stabilization based on their relative effectiveness was used. Trials were also made to economize the cost of stabilization from both conventional additives by controlled replacing of them with waste polythene and polyester fibers. The construction methodology for stabilization using waste fibers was also proposed. Cement was observed to be the most effective stabilizer with respect to strength and durability for A-3(0) soils. Bitumen was found effective but uneconomical for A-3(0) soils. Waste polythene and polyester wastes (organic materials) have potential to economize the cost of stabilization with cement and bitumen for A-3(0) soils. However, long term degradation of these organic materials in soil stabilized mixtures needs further exploration. (author)
Directory of Open Access Journals (Sweden)
Xueying Zhao
2017-11-01
Full Text Available It is a consensus that salt heaving and frost heaving are urgent and typical distress in the sulfate saline soil area. To further investigate the microscopic performance of pavement structure in this special area, Jinan-Dongying Freeway in Shandong Province is selected as a case study engineering and the mechanic responses under salt heaving, frost heaving and traffic loads were analyzed through the finite element (FE Program (ANSYS. In this paper, the process of salt heaving and frost heaving was divided into 3 stages and FE models were established based on fluid–structure interaction (FSI model. It is shown that under both effects of salt heaving and frost heaving, the tensile stress of asphalt surface course could be up to 96.75% of its tensile strength, which means its tensile strength was seriously inadequate; however, traffic loads could help to dramatically counteract effects of salt heaving and frost heaving, which could decrease 40–80% of the tensile stress in asphalt surface course. It is also shown that in Jinan-Dongying Freeway effects of salt heaving had slightly larger effects on pavement compared with that of frost heaving, probably because salt heaving occurred from the top to the bottom of subgrade. However, as a whole, in sulfate saline soil area, compared with general area, crack resistance of asphalt courses and foundation treatment should always be strengthened. Keywords: Sulfate saline soil subgrade, Asphalt pavement, Pavement mechanic, FEM, FSI, Cracks and bulging
Resilient modulus characteristics of soil subgrade with geopolymer additive in peat
Zain, Nasuhi; Hadiwardoyo, Sigit Pranowo; Rahayu, Wiwik
2017-06-01
Resilient modulus characteristics of peat soil are generally very low with high potential of deformation and low bearing capacity. The efforts to improve the peat subgrade resilient modulus characteristics is required, one among them is by adding the geopolymer additive. Geopolymer was made as an alternative to replace portland cement binder in the concrete mix in order to promote environmentally friendly, low shrinkage value, low creep value, and fire resistant material. The use of geopolymer to improve the mechanical properties of peat as a road construction subgrade, hence it becomes important to identify the effect of geopolymer addition on the resilient modulus characteristics of peat soil. This study investigated the addition of 0% - 20% geopolymer content on peat soil derived from Ogan Komering Ilir, South Sumatera Province. Resilient modulus measurement was performed by using cyclic triaxial test to determine the resilience modulus model as a function of deviator stresses and radial stresses. The test results showed that an increase in radial stresses did not necessarily lead to an increase in modulus resilient, and on the contrary, an increase in deviator stresses led to a decrease in modulus resilient. The addition of geopolymer in peat soil provided an insignificant effect on the increase of resilient modulus value.
Experimental Study on the Utilization of Fine Steel Slag on Stabilizing High Plastic Subgrade Soil
Directory of Open Access Journals (Sweden)
Hussien Aldeeky
2017-01-01
Full Text Available The three major steel manufacturing factories in Jordan dump their byproduct, steel slag, randomly in open areas, which causes many environmental hazardous problems. This study intended to explore the effectiveness of using fine steel slag aggregate (FSSA in improving the geotechnical properties of high plastic subgrade soil. First soil and fine steel slag mechanical and engineering properties were evaluating. Then 0%, 5%, 10%, 15%, 20%, and 25% dry weight of soil of fine steel slag (FSSA were added and mixed into the prepared soil samples. The effectiveness of the FSSA was judged by the improvement in consistency limits, compaction, free swell, unconfined compression strength, and California bearing ratio (CBR. From the test results, it is observed that 20% FSSA additives will reduce plasticity index and free swell by 26.3% and 58.3%, respectively. Furthermore, 20% FSSA additives will increase the unconfined compressive strength, maximum dry density, and CBR value by 100%, 6.9%, and 154%. By conclusion FSSA had a positive effect on the geotechnical properties of the soil and it can be used as admixture in proving geotechnical characteristics of subgrade soil, not only solving the waste disposal problem.
Shizgal, Bernie D.; Chikhaoui, Aziz
2006-06-01
The present paper considers a detailed analysis of the nonequilibrium effects for a model reactive system with the Chapman-Eskog (CE) solution of the Boltzmann equation as well as an explicit time dependent solution. The elastic cross sections employed are a hard sphere cross section and the Maxwell molecule cross section. Reactive cross sections which model reactions with and without activation energy are used. A detailed comparison is carried out with these solutions of the Boltzmann equation and the approximation introduced by Cukrowski and coworkers [J. Chem. Phys. 97 (1992) 9086; Chem. Phys. 89 (1992) 159; Physica A 188 (1992) 344; Chem. Phys. Lett. A 297 (1998) 402; Physica A 275 (2000) 134; Chem. Phys. Lett. 341 (2001) 585; Acta Phys. Polonica B 334 (2003) 3607.] based on the temperature of the reactive particles. We show that the Cukrowski approximation has limited applicability for the large class of reactive systems studied in this paper. The explicit time dependent solutions of the Boltzmann equation demonstrate that the CE approach is valid only for very slow reactions for which the corrections to the equilibrium rate coefficient are very small.
Rate Coefficients of the Reaction of OH with Allene and Propyne at High Temperatures
Es-sebbar, Et-touhami
2016-09-28
Allene (H2C═C═CH2; a-C3H4) and propyne (CH3C≡CH; p-C3H4) are important species in various chemical environments. In combustion processes, the reactions of hydroxyl radicals with a-C3H4 and p-C3H4 are critical in the overall fuel oxidation system. In this work, rate coefficients of OH radicals with allene (OH + H2C═C═CH2 → products) and propyne (OH + CH3C≡CH → products) were measured behind reflected shock waves over the temperature range of 843–1352 K and pressures near 1.5 atm. Hydroxyl radicals were generated by rapid thermal decomposition of tert-butyl hydroperoxide ((CH3)3–CO–OH), and monitored by narrow line width laser absorption of the well-characterized R1(5) electronic transition of the OH A–X (0,0) electronic system near 306.7 nm. Results show that allene reacts faster with OH radicals than propyne over the temperature range of this study. Measured rate coefficients can be expressed in Arrhenius form as follows: kallene+OH(T) = 8.51(±0.03) × 10–22T3.05 exp(2215(±3)/T), T = 843–1352 K; kpropyne+OH(T) = 1.30(±0.07) × 10–21T3.01 exp(1140(±6)/T), T = 846–1335 K.
International Nuclear Information System (INIS)
Stiller, W.
1985-01-01
A classical collision theory is used to describe thermal bimolecular rate coefficeints for reaction between positive and negative ions and polar molecules in a carrier gas. Special attention is paid to ion-molecule reaction in which proton transfer occurs. These reactions play an important role in terrestrial plasma devices, in ionosphere, in planetary atmospheres and in interstellar matter. The equilibrium rate coefficients of the reactions are calculated based on a microscopic reactive cross section derived from a long distance polar molecule-ion potential. The results are compared with experimental values of afterglow measurements. (D.Gy.)
Torr, D. G.; Torr, M. R.
1980-01-01
Atmosphere Explorer-C satellite measurements are used to determine rate coefficients (RCs) for the following reactions: O(+)(D-2) + N2 yields N2(+) + O (reaction 1), O(+)(D-2) + N2 yields O(+)(S-4) + N2 (reaction 2), and O(+)(D-2) + N2 yields NO(+) + N (reaction 3). Results show the RC for reaction 1 to be 1 (plus 1 or minus 0.5) x 10 to the -10th cu cm per sec, for reaction 2 to be 3 (plus 1 or minus 2) x 10 to the -11th cu cm per sec, and 3 to be less than 5.5 x 10 to the -11th cu cm per sec. It is also found that the reaction of O(+)(D-2) with N2 does not constitute a detectable source of NO(+) ions in the thermosphere.
Determination of the reaction rate coefficient of sulphide mine tailings deposited under water.
Awoh, Akué Sylvette; Mbonimpa, Mamert; Bussière, Bruno
2013-10-15
The efficiency of a water cover to limit dissolved oxygen (DO) availability to underlying acid-generating mine tailings can be assessed by calculating the DO flux at the tailings-water interface. Fick's equations, which are generally used to calculate this flux, require knowing the effective DO diffusion coefficient (Dw) and the reaction (consumption) rate coefficient (Kr) of the tailings, or the DO concentration profile. Whereas Dw can be accurately estimated, few studies have measured the parameter Kr for submerged sulphide tailings. The objective of this study was to determine Kr for underwater sulphide tailings in a laboratory experiment. Samples of sulphide mine tailings (an approximately 6 cm layer) were placed in a cell under a water cover (approximately 2 cm) maintained at constant DO concentration. Two tailings were studied: TA1 with high sulphide content (83% pyrite) and TA2 with low sulphide content (2.8% pyrite). DO concentration was measured with a microelectrode at various depths above and below the tailings-water interface at 1 mm intervals. Results indicate that steady-state condition was rapidly attained. As expected, a diffusive boundary layer (DBL) was observed in all cases. An iterative back-calculation process using the numerical code POLLUTEv6 and taking the DBL into account provided the Kr values used to match calculated and experimental concentration profiles. Kr obtained for tailings TA1 and TA2 was about 80 d(-1) and 6.5 d(-1), respectively. For comparison purposes, Kr obtained from cell tests on tailings TA1 was lower than Kr calculated from the sulphate production rate obtained from shake-flask tests. Steady-state DO flux at the water-tailings interface was then calculated with POLLUTEv6 using tailings characteristics Dw and Kr. For the tested conditions, DO flux ranged from 608 to 758 mg O2/m(2)/d for tailings TA1 and from 177 to 221 mg O2/m(2)/d for tailings TA2. The impact of placing a protective layer of inert material over
2012-03-01
This research study aims at evaluating the performance of base and subgrade soil in flexible pavements under repeated loading test conditions. For this purpose, an indoor cyclic plate load testing equipment was developed and used to conduct a series ...
Determination of the side-reaction coefficient of desferrioxamine B in trace-metal-free seawater
Directory of Open Access Journals (Sweden)
Johan Schijf
2016-07-01
Full Text Available Electrochemical techniques like adsorptive cathodic stripping voltammetry with competitive ligand equilibration (ACSV-CLE can determine total concentrations of marine organic ligands and their conditional binding constants for specific metals, but cannot identify them. Individual organic ligands, isolated from microbial cultures or biosynthesized through genomics, can be structurally characterized via NMR and tandem MS analysis, but this is tedious and time-consuming. A complementary approach is to compare known properties of natural ligands, particularly their conditional binding constants, with those of model organic ligands, measured under suitable conditions. Such comparisons cannot be meaningfully interpreted unless the side-reaction coefficient (SRC of the model ligand in seawater is thoroughly evaluated.We conducted series of potentiometric titrations, in non-coordinating medium at seawater ionic strength (0.7 M NaClO4 over a range of metal:ligand molar ratios, to study complexation of the siderophore desferrioxamine B (DFOB with Mg and Ca, for which it has the highest affinity among the major seasalt cations. From similar titrations of acetohydroxamic acid in the absence and presence of methanesulfonate (mesylate, it was determined that Mg and Ca binding to this common DFOB counter-ion is not strong enough to interfere with the DFOB titrations. Stability constants were measured for all DFOB complexes with Mg and Ca including, for the first time, the bidentate complexes. No evidence was found for Mg and Ca coordination with the DFOB terminal amine. From the improved DFOB speciation, we calculated five SRCs for each of the five (deprotonated forms of DFOB in trace-metal-free seawater, yet we also present a more convenient definition of a single SRC that allows adjustment of all DFOB stability constants to seawater conditions, no matter which of these forms is selected as the 'component' (reference species. An example of Cd speciation in
Ng, Maggie; Mok, Daniel K W; Lee, Edmond P F; Dyke, John M
2017-09-07
A theoretical study, involving the calculation of reaction enthalpies, activation energies, mechanisms, and rate coefficients, was made of the reaction of hydroxyl radicals with methyl nitrate, an important process for methyl nitrate removal in the earth's atmosphere. Four reaction channels were considered: formation of H 2 O + CH 2 ONO 2 , CH 3 OOH + NO 2 , CH 3 OH + NO 3 , and CH 3 O + HNO 3 . For all channels, geometry optimization and frequency calculations were performed at the M06-2X/6-31+G** level, while relative energies were improved at the UCCSD(T*)-F12/CBS level. The major channel is found to be the H abstraction channel, to give the products H 2 O + CH 2 ONO 2 . The reaction enthalpy (ΔH 298 K RX ) of this channel is computed as -17.90 kcal mol -1 . Although the other reaction channels are also exothermic, their reaction barriers are high (>24 kcal mol -1 ), and therefore these reactions do not contribute to the overall rate coefficient in the temperature range considered (200-400 K). Pathways via three transition states were identified for the H abstraction channel. Rate coefficients were calculated for these pathways at various levels of variational transition state theory including tunneling. The results obtained are used to distinguish between two sets of experimental rate coefficients, measured in the temperature range of 200-400 K, one of which is approximately an order of magnitude greater than the other. This comparison, as well as the temperature dependence of the computed rate coefficients, shows that the lower experimental values are favored. The implications of the results to atmospheric chemistry are discussed.
Nie, Yihua; Tang, Saiqian; Xu, Yang; Mao, Kunli
2018-04-01
In order to obtain mechanical response distribution of herringbone frame structure for highway subgrade slopes protection and select the best structure type, 3D numerical models of three types herringbone frame structure were established and analyzed in finite element software ANSYS. Indoor physical model of soil slope protected by herringbone frame structure was built and mechanical response of the frame structure was measured by loading tests. Numerical results indicate slope foot is the stress most disadvantageous location. Comparative analysis shows that structure composed of mortar rubble base layer and precast concrete blocks paving layer is the best one for resisting deformation and structure with cement mortar base layer and precast concrete blocks paving layer is the best one for being of low stress.
Effect of drains on the seepage of contaminants from subgrade tailings disposal areas
International Nuclear Information System (INIS)
Witten, A.J.; Pin, F.G.; Sharp, R.D.
1984-01-01
A numerical simulation study is performed to investigate the influence of ponded water and a bottom drain on the pathways for contaminant migration from a subgrade uranium mill tailings disposal pit. A numerical model is applied to a generic disposal pit constructed with a bottom clay liner and steep unlined sidewalls. The migration of a two-contaminant system is modeled assuming that neither contaminant decays and only one contaminant is retarded. Two dominant pathways are identified; one associated with lateral sidewall leakage and the other associated with transport through the bottom clay liner. It is found that the drain serves to reduce migration through the sidewall which, in turn, prevents the retarded contaminant from reaching the aquifer. The ponded water provides increased head which causes an accelerated vertical movement of moisture through the clay liner. 2 references, 8 figures
The effect of drains on the seepage of contaminants from subgrade tailings disposal areas
International Nuclear Information System (INIS)
Witten, A.J.; Pin, F.G.; Sharp, R.D.
1984-01-01
A numerical simulation study is performed to investigate the influence of ponded water and a bottom drain on the pathways for contaminant migration from a subgrade uranium mill tailings disposal pit. A numerical model is applied to a generic disposal pit constructed with a bottom clay liner and steep unlined sidewalls. The migration of a two-contaminant system is modeled assuming that neither contaminant decays and only one contaminant is retarded. Two dominant pathways are indentified; one associated with lateral sidewall leakage and the other associated with transport through the bottom clay liner. It is found that the drain serves to reduce migration through the sidewall which, in turn, prevents the retarded contaminant from reaching the aquifer. The ponded water provides increased head which causes an accelarated vertical movement of moisture through the clay liner
Subgrade stabilization alternatives to lime and cement.
2010-04-15
This project involved four distinct research activities, (1) the influence of temperature on lime-stabilized soils, (2) the influence of temperature on cement-stabilized soils (3) temperature modeling of stabilized subgrade and (4) use of calcium chl...
2008-07-01
Often subgrade soils exhibit properties, particularly strength and/or volume change properties that limit their performance as a support element for pavements. : Typical problems include shrink-swell, settlement, collapse, erosion or simply insuffici...
2009-01-01
Soils often undergo cyclic wetting/drying, but there is very limited research on unsaturated : soils subjected to variations in moisture content. More specifically, field moisture variation : over time in highway unbound bases and subgrade soils is a...
Litniewski, Marek; Gorecki, Jerzy
2011-06-28
We have performed intensive computer simulations of the irreversible annihilation reaction: A + A → C + C and of the trapping reaction: A + B → C + B for a variety of three-dimensional fluids composed of identical spherical particles. We have found a significant difference in the asymptotic behavior of the rate coefficients for these reactions. Both the rate coefficients converge to the same value with time t going to infinity but the convergence rate is different: the O(t(-1/2)) term for the annihilation reaction is higher than the corresponding term for the trapping reaction. The simulation results suggest that ratio of the terms is a universal quantity with the value equal to 2 or slightly above. A model for the annihilation reaction based on the superposition approximation predicts the difference in the O(t(-1/2)) terms, but overestimates the value for the annihilation reaction by about 30%. We have also performed simulations for the dimerization process: A + A → E, where E stands for a dimer. The dimerization decreases the reaction rate due to the decrease in the diffusion constant for A. The effect is successfully predicted by a simple model.
DEFF Research Database (Denmark)
Jeong, Cheol-Ho
2011-01-01
resistivity and the absorber thickness on the difference between the two surface reaction models are examined and discussed. For a porous absorber backed by a rigid surface, the local reaction models give errors of less than 10% if the thickness exceeds 120 mm for a flow resistivity of 5000 Nm-4s. As the flow...... incidence acoustical characteristics of typical building elements made of porous materials assuming extended and local reaction. For each surface reaction, five well-established wave propagation models, the Delany-Bazley, Miki, Beranek, Allard-Champoux, and Biot model, are employed. Effects of the flow...... resistivity doubles, a decrease in the required thickness by 25 mm is observed to achieve the same amount of error. For an absorber backed by an air gap, the thickness ratio between the material and air cavity is important. If the absorber thickness is approximately 40% of the cavity depth, the local reaction...
International Nuclear Information System (INIS)
HOPKINS, A.M.; KLOS, D.B.
2007-01-01
In 2002, the Richland Operations Office (RL) of the US Department of Energy (DOE), the US Environmental Protection Agency (EPA), and the Washington State Department of Ecology (Ecology) developed milestones for transitioning the Plutonium Finishing Plant (PFP) facility to a clean slab-on-grade configuration. These milestones required developing an engineering evaluation/cost analysis (EF/CA) for the facility's sub-grade structures and installations as part of a series of evaluations intended to provide for the transition of the facility to a clean slab-on-grade configuration. In addition to supporting decisions for interim actions, the analyses of sub-grade structures and installations performed through this EE/CA will contribute to the remedial investigation feasibility study(ies) and subsequently to the final records of decision for the relevant operable units responsible for site closure in the 200 West Area of the Hanford Site
Barbosa, Thaís da Silva; Peirone, Silvina; Barrera, Javier A; Abrate, Juan P A; Lane, Silvia I; Arbilla, Graciela; Bauerfeldt, Glauco Favilla
2015-04-14
The kinetics of the cis-3-hexene + OH reaction were investigated by an experimental relative rate method and at the density functional theory level. The experimental set-up consisted of a 200 L Teflon bag, operated at atmospheric pressure and 298 K. OH radicals were produced by the photolysis of H2O2 at 254 nm. Relative rate coefficients were determined by comparing the decays of the cis-3-hexene and reference compounds (cyclohexene, 2-buten-1-ol and allyl ether). The mean second-order rate coefficient value found was (6.27 ± 0.66) × 10(-11) cm(3) molecule(-1) s(-1), the uncertainty being estimated by propagation of errors. Theoretical calculations for the addition reaction of OH to cis-3-hexene have also been performed, at the BHandHLYP/aug-cc-pVDZ level, in order to investigate the reaction mechanism, to clarify the experimental observations and to model the reaction kinetics. Different conformations of the reactants, pre-barrier complexes and saddle points were considered in our calculations. The individual rate coefficients, calculated for each conformer of the reactant, at 298 K, using a microcanonical variational transition state method, are 4.19 × 10(-11) and 1.23 × 10(-10) cm(3) molecule(-1) s(-1). The global rate coefficient was estimated from the Boltzmann distribution of the conformers to be 8.10 × 10(-11) cm(3) molecule(-1) s(-1), which is in agreement with the experimental value. Rate coefficients calculated over the temperature range from 200-500 K are also given. Our results suggest that the complex mechanism, explicitly considering different conformations for the stationary points, must be taken into account for a proper description of the reaction kinetics.
Proof Rolling of Foundation Soil and Prepared Subgrade During Construction
2017-07-04
The primary objective of this project is to develop multiple simulation testbeds and transportation models to evaluate the impacts of Connected Vehicle Dynamic Mobility Applications (DMA) and Active Transportation and Demand Management (ATDM) strateg...
potentials of cement kiln dust in sub-grade improvement
African Journals Online (AJOL)
2013-03-01
Mar 1, 2013 ... alternative uses of waste materials in different geotech- nical application including .... tained in bags and stored in air tight containers. The. CKD was ... Figure 5: Variation of plastic limit with cement kiln dust. Figure 6: Variation ...
Special Provisions for Intelligent Compaction of Stabilized Soil Subgrades
2017-12-30
Slowing the deterioration of highway infrastructure, reducing carbon emissions, conserving resources, repurposing industrial waste-this Exploratory Advanced Research (EAR) Program project is pursuing multiple benefits through a unique experimental ap...
International Nuclear Information System (INIS)
Herbst, E.; Leung, C.M.; Rensselaer Polytechnic Institute, Troy, NY)
1986-01-01
Pseudo-time-dependent models of the gas phase chemistry of dense interstellar clouds have been run with large rate coefficients for reactions between ions and polar neutral species, as advocated by Adams, Smith, and Clary. The higher rate coefficients normally lead to a reduction in both the peak and steady state abundances of polar neutrals, which can be as large as an order of magnitude but is more often smaller. Other differences between the results of these models and previous results are also discussed. 38 references
DEFF Research Database (Denmark)
Jeong, Cheol-Ho
2011-01-01
resistivity and the absorber thickness on the difference between the two surface reaction models are examined and discussed. For a porous absorber backed by a rigid surface, the assumption of local reaction always underestimates the random incidence absorption coefficient and the local reaction models give...... incidence acoustical characteristics of typical building elements made of porous materials assuming extended and local reaction. For each surface reaction, five well-established wave propagation models, the Delany-Bazley, Miki, Beranek, Allard-Champoux, and Biot model, are employed. Effects of the flow...... errors of less than 10% if the thickness exceeds 120 mm for a flow resistivity of 5000 Nm-4s. As the flow resistivity doubles, a decrease in the required thickness by 25 mm is observed to achieve the same amount of error. For an absorber backed by an air gap, the thickness ratio between the material...
Directory of Open Access Journals (Sweden)
Lingshi An
2018-01-01
Full Text Available This paper presents the dynamic compressive stress response of pavement-subgrade induced by moving heavy-duty trucks. In order to study the distribution characteristic of dynamic pressure of pavement-subgrade in more detail, truck loadings, truck speeds, and dynamic pressure distributions at different depths were monitored under twenty-five working conditions on the section of Qiqihar-Nenjiang Highway in Heilongjiang Province, China. The effects of truck loading, truck speed, and depth on dynamic compressive stress response can be concluded as follows: (1 increasing truck loading will increase the dynamic pressure amplitude of subgrade-pavement and dominant frequencies are close to the characteristic frequencies caused by heavy-duty trucks at the speed of 70 km/h; (2 as truck speed increases, the dynamic pressure amplitudes of measuring points have an increasing tendency; the dynamic pressure spectrums are also significantly influenced by truck speed: the higher the truck speed, the wider the spectrum and the higher the dominant frequencies; (3 as depth increases, the dynamic pressure amplitudes of measuring points decrease rapidly. The influence of the front axle decreases gradually until disappearing and the compressive stress superposition phenomenon caused by rear double axles can be found with increasing depth.
Gas-phase rate coefficients of the reaction of ozone with four sesquiterpenes at 295 ± 2 K.
Richters, Stefanie; Herrmann, Hartmut; Berndt, Torsten
2015-05-07
The rate coefficients of the reaction of ozone with the four atmospherically relevant sesquiterpenes β-caryophyllene, α-humulene, α-cedrene and isolongifolene were investigated at 295 ± 2 K and atmospheric pressure by at least two independent experimental investigations for each reaction. Relative rate experiments were carried out in a flow tube using two different experimental approaches with GC-MS detection (RR 1) and PTR-MS analysis (RR 2) as the analytical techniques. Absolute rate coefficients were determined in a stopped-flow experiment following the ozone depletion by means of UV spectroscopy. The average rate coefficients from the combined investigations representing the mean values of the different experimental methods are (unit: cm(3) molecule(-1) s(-1)): k(O3+β-caryophyllene) = (1.1 ± 0.3) × 10(-14) (methods: RR 1, RR 2, absolute), k(O3+α-humulene) = (1.2 ± 0.3) × 10(-14) (RR 1, RR 2), k(O3+α-cedrene) = (1.7 ± 0.5) × 10(-16) (RR 2, absolute) and k(O3+isolongifolene) = (1.1 ± 0.5) × 10(-17) (RR 2, absolute). The high ozonolysis rate coefficients for β-caryophyllene and α-humulene agree well with the results by Shu and Atkinson (Int. J. Chem. Kinet., 1994, 26) and lead to short atmospheric lifetimes of about two minutes with respect to the ozone reaction. The relatively small rate coefficients for α-cedrene and isolongifolene differ from the available literature values by a factor of about 2.5-6. Possible reasons for the deviations are discussed. Finally, calibrated sesquiterpene FT-IR spectra were recorded for the first time.
International Nuclear Information System (INIS)
Chang, T.; Torr, D.G.; Richards, P.G.; Solomon, S.C.
1993-01-01
O + ( 2 P) is an important species for studies of the ionosphere and thermosphere: its emission at 7320 angstrom can be used as a diagnostic of the thermospheric atomic oxygen density. Unfortunately, there are no laboratory measurements of the O and N 2 reaction rates which are needed to determine the major sinks of O + ( 2 P). The reaction rates that are generally used were determined from aeronomic data by Rusch et al. but there is evidence that several important inputs that they used should be changed. The authors have recalculated the O and N 2 reaction rates for O + ( 2 P) using recent improvements in the solar EUV flux, cross sections, and photoelectron fluxes. For the standard solar EUV flux, the new N 2 reaction rate of 3.4 ± 1.5 x 10 -10 cm 3 s -1 is close to the value obtained by Rusch et al., but the new O reaction rate of 4.0 ± 1.9 x 10 -10 cm 3 s -1 is about 8 times larger. These new reaction rates are derived using neutral densities, electron density, and solar EUV fluxes measured by Atmosphere Explorer C in 1974 during solar minimum. The new theoretical emission rates are in good agreement with the data for the two orbits studied by Rusch et al. and they are in reasonable agreement with data from five additional orbits that are used in this study. The authors have also examined the effect of uncertainties in the solar EUV flux on the derived reaction rates and found that 15% uncertainties in the solar flux could cause additional uncertainties of up to a factor of 1.5 in the O quenching rate. 19 refs., 4 figs., 8 tabs
Chang, T.; Torr, D. G.; Richards, P. G.; Solomon, S. C.
1993-01-01
O(+)(2P) is an important species for studies of the ionosphere and thermosphere: its emission at 7320 A can be used as a diagnostic of the thermospheric atomic oxygen density. Unfortunately, there are no laboratory measurements of the O and N2 reaction rates which are needed to determine the major sinks of (O+)(2p). We have recalculated the O and N2 reaction rates for O(+) (2P) using recent improvements in the solar EUV flux, cross sections, and photoelectron fluxes. For the standard solar EUV flux, the new N2 reaction rate of 3.4 +/- 1.5 x 10 exp -10 cu cm/s is close to the value obtained by Rusch et al. (1977), but the new O reaction rate of 4.0 +/- 1.9 x 10 exp -10 cu cm/sec is about 8 times larger. These new reaction rates are derived using neutral densities, electron density, and solar EUV fluxes measured by Atmosphere Explorer C in 1974 during solar minimum. The new theoretical emission rates are in good agreement with the data for the two orbits studied by Rusch et al.
Rate Coefficient Measurements and Theoretical Analysis of the OH + ( E) CF3CH=CHCF3 Reaction.
Baasandorj, Munkhbayar; Marshall, Paul; Waterland, Robert L; Ravishankara, Akkihebbal R; Burkholder, James B
2018-04-25
Rate coefficients, k, for the gas-phase reaction of the OH radical with (E) CF3CH=CHCF3 ((E)-1,1,14,4,4-hexafluoro-2-butene, HFO-1336mzz(E)) were measured over a range of temperature (211-374 K) and bath gas pressure (20-300 Torr; He, N2) using a pulsed laser photolysis-laser induced fluorescence (PLP-LIF) technique. k1(T) was independent of pressure over this range of conditions with k1(296 K) = (1.31 ± 0.15) × 10 13 cm3 molecule 1 s 1 and k1(T) = (6.94 ± 0.80) × 10 13 exp[ (496 ± 10)/T] cm3 molecule 1 s 1, where the uncertainties are 2 and the pre-exponential term includes estimated systematic error. Rate coefficients for the OD reaction were also determined over a range of temperature (262-374 K) at 100 Torr (He). The OD rate coefficients were ~15% greater than the OH values and showed similar temperature dependent behavior with k2(T) = (7.52 ± 0.44) × 10 13 exp[ (476 ± 20)/T] and k2(296 K) = (1.53 ± 0.15) × 10 13 cm3 molecule 1 s 1. The rate coefficients for reaction 1 were also measured using a relative rate technique between 296 and 375 K with k1(296 K) measured to be (1.22 ± 0.1) × 10 13 cm3 molecule 1 s 1 in agreement with the PLP-LIF results. In addition, the 296 K rate coefficient for the O3 + (E) CF3CH=CHCF3 reaction was determined to be reaction and the significant decrease in OH reactivity compared to the (Z) CF3CH=CHCF3 stereoisomer reaction. The estimated atmospheric lifetime of (E) CF3CH=CHCF3, due to loss by reaction with OH, is estimated to be ~90 days, while the actual lifetime will depend on the location and season of its emission. Infrared absorption spectra of (E) CF3CH=CHCF3 were measured and used to estimate the 100-year time horizon global warming potentials (GWP) of 32 (atmospherically well-mixed) and 14 (lifetime-adjusted).
Determination of the rate coefficient for the N2/+/ + O reaction in the ionosphere
Torr, D. G.; Torr, M. R.; Orsini, N.; Hanson, W. B.; Hoffman, J. H.; Walker, J. C. G.
1977-01-01
Using approximately 400 simultaneous measurements of ion and neutral densities and temperatures, and the spectrum of the solar flux measured by the Atmosphere Explorer C satellite, we have determined the rate constant k1 for the reaction between N2(+) and O in the ionosphere for ion temperatures between 600 and 700 K. We find that k1 = 1.1 x 10 to the minus 10th power cu cm per sec, with a standard deviation of + or - 15%. If we use the temperature dependence for this reaction determined in the laboratory then at 300 K we find excellent agreement with the recommended laboratory value.
Melanoidins extinction coefficient in the glucose/glycine Maillard reaction
Martins, S.I.F.S.; Boekel, van M.A.J.S.
2003-01-01
Melanoidins (brown, nitrogenous polymers and co-polymers) are the final products of the Maillard reaction. The glucose/glycine melanoidins extinction coefficient was determined using C-14-labelled glucose at three different reaction conditions. The absorbance was measured at different wavelengths
International Nuclear Information System (INIS)
Bekstein, A; De Urquijo, J; Rodríguez-Luna, J C; Juárez, A M; Ducasse, O
2012-01-01
We present in this paper the interpretation and analysis of transient pulses from a pulsed Townsend experiment by solving the continuity equations of the charged carriers (electrons and ions) involved in the avalanche. The set of second order partial differential equations is solved by SIMAV, a simulator designed specifically for the pulsed Townsend avalanche. Complex situations involving processes such as electron detachment, ion-molecule reactions, Penning ionization and secondary electron emission from ion impact at the cathode, virtually impossible to solve analytically, are discussed here to illustrate the capability of the simulator to help explain the various reaction processes involved in the avalanche, and also to derive some of the transport and reaction coefficients.
Ballesteros, Bernabé; Ceacero-Vega, Antonio A; Jiménez, Elena; Albaladejo, José
2015-04-01
As the result of biogenic and anthropogenic activities, large quantities of chemical compounds are emitted into the troposphere. Alkanes, in general, and cycloalkanes are an important chemical class of hydrocarbons found in diesel, jet and gasoline, vehicle exhaust emissions, and ambient air in urban areas. In general, the primary atmospheric fate of organic compounds in the gas phase is the reaction with hydroxyl radicals (OH). The oxidation by Cl atoms has gained importance in the study of atmospheric reactions because they may exert some influence in the boundary layer, particularly in marine and coastal environments, and in the Arctic troposphere. The aim of this paper is to study of the atmospheric reactivity of methylcylohexanes with Cl atoms and OH radicals under atmospheric conditions (in air at room temperature and pressure). Relative kinetic techniques have been used to determine the rate coefficients for the reaction of Cl atoms and OH radicals with methylcyclohexane, cis-1,4-dimethylcyclohexane, trans-1,4-dimethylcyclohexane, and 1,3,5-trimethylcyclohexane at 298 ± 2 K and 720 ± 5 Torr of air by Fourier transform infrared) spectroscopy and gas chromatography-mass spectrometry (GC-MS) in two atmospheric simulation chambers. The products formed in the reaction under atmospheric conditions were investigated using a 200-L Teflon bag and employing the technique of solid-phase microextraction coupled to a GC-MS. The rate coefficients obtained for the reaction of Cl atoms with the studied compounds are the following ones (in units of 10(-10) cm(3) molecule(-1) s(-1)): (3.11 ± 0.16), (2.89 ± 0.16), (2.89 ± 0.26), and (2.61 ± 0.42), respectively. For the reactions with OH radicals the determined rate coefficients are (in units of 10(-11) cm(3) molecule(-1) s(-1)): (1.18 ± 0.12), (1.49 ± 0.16), (1.41 ± 0.15), and (1.77 ± 0.23), respectively. The reported error is twice the standard deviation. A detailed
Baasandorj, Munkhbayar; Ravishankara, A R; Burkholder, James B
2011-09-29
Rate coefficients, k, for the gas-phase reaction of the OH radical with (Z)-CF(3)CH═CHCF(3) (cis-1,1,1,4,4,4-hexafluoro-2-butene) were measured under pseudo-first-order conditions in OH using pulsed laser photolysis (PLP) to produce OH and laser-induced fluorescence (LIF) to detect it. Rate coefficients were measured over a range of temperatures (212-374 K) and bath gas pressures (20-200 Torr; He, N(2)) and found to be independent of pressure over this range of conditions. The rate coefficient has a non-Arrhenius behavior that is well-described by the expression k(1)(T) = (5.73 ± 0.60) × 10(-19) × T(2) × exp[(678 ± 10)/T] cm(3) molecule(-1) s(-1) where k(1)(296 K) was measured to be (4.91 ± 0.50) × 10(-13) cm(3) molecule(-1) s(-1) and the uncertainties are at the 2σ level and include estimated systematic errors. Rate coefficients for the analogous OD radical reaction were determined over a range of temperatures (262-374 K) at 100 Torr (He) to be k(2)(T) = (4.81 ± 0.20) × 10(-19) × T(2) × exp[(776 ± 15)/T], with k(2)(296 K) = (5.73 ± 0.50) × 10(-13) cm(3) molecule(-1) s(-1). OH radical rate coefficients were also measured at 296, 345, and 375 K using a relative rate technique and found to be in good agreement with the PLP-LIF results. A room-temperature rate coefficient for the O(3) + (Z)-CF(3)CH═CHCF(3) reaction was measured using an absolute method with O(3) in excess to be reaction was estimated to be ~20 days. Infrared absorption spectra of (Z)-CF(3)CH═CHCF(3) measured in this work were used to determine a (Z)-CF(3)CH═CHCF(3) global warming potential (GWP) of ~9 for the 100 year time horizon. A comparison of the OH reactivity of (Z)-CF(3)CH═CHCF(3) with other unsaturated fluorinated compounds is presented.
Stabilization treatment of soft subgrade soil by sewage sludge ash and cement.
Chen, Li; Lin, Deng-Fong
2009-02-15
In this study, incinerated sewage sludge ash (ISSA) is mixed with cement in a fixed ratio of 4:1 for use as a stabilizer to improve the strength of soft, cohesive, subgrade soil. Five different ratios (in wt%: 0%, 2%, 4%, 8%, and 16%) of ISSA/cement admixture are mixed with cohesive soil to make soil samples. In order to understand the influences of admixtures on the soil properties, tests of the pH value, Atterberg limits, compaction, California bearing ratio (CBR), unconfined compressive strength, and triaxial compression were performed on those samples. The study shows that the unconfined compressive strength of specimens with the ISSA/cement addition was improved to approximately 3-7 times better than that of the untreated soil; furthermore, the swelling behavior was also effectively reduced as much as 10-60% for those samples. In some samples, the ISSA/cement additive improved the CBR values by up to 30 times that of untreated soil. This suggests that ISSA/cement has many potential applications in the field of geotechnical engineering.
Characterization of cementitiously stabilized subgrades for mechanistic-empirical pavement design
Solanki, Pranshoo
Pavements are vulnerable to subgrade layer performance because it acts as a foundation. Due to increase in the truck traffic, pavement engineers are challenged to build more strong and long-lasting pavements. To increase the load-bearing capacity of pavements, subgrade layer is often stabilized with cementitious additives. Thus, an overall characterization of stabilized subgrade layer is important for enhanced short- and long-term pavement performance. In this study, the effect of type and amount of additive on the short-term performance in terms of material properties recommended by the new Mechanistic-Empirical Pavement Design Guide (MEPDG) is examined. A total of four soils commonly encountered as subgrades in Oklahoma are utilized. Results show that the changes in the Mr, ME and UCS values stabilized specimens depend on the soil type and properties of additives. The long-term performance (or durability) of stabilized soil specimens is investigated by conducting freeze-thaw (F-T) cycling, vacuum saturation and tube suction tests on 7-day cured P-, K- and C-soil specimens stabilized with 6% lime, 10% CFA and 10% CKD. This study is motivated by the fact that during the service life of pavement stabilized layers are subjected to F-T cycles and moisture variations. It is found that that UCS value of all the stabilized specimens decreased with increase in the number of F-T cycles. A strong correlation was observed between UCS values retained after vacuum saturation and F-T cycles indicating that vacuum saturation could be used as a time-efficient and inexpensive method for evaluating durability of stabilized soils. In this study, short- and long-term observations from stabilization of sulfate bearing soil with locally available low (CFA), moderate (CKD) and high (lime) calcium-based stabilizers are determined to evaluate and compare the effect of additive type on the phenomenon of sulfate-induced heave. The impact of different factors on the development of the
Institute of Scientific and Technical Information of China (English)
王宁
2017-01-01
介绍了填石路基的施工技术与质量控制要点,并以某公路工程为例,从基底施工、路基清理、边坡码砌、摊铺填料、路基平整等方面,阐述了填石路基的施工技术,提高了路基的性能.%The paper introduces the construction technique and quality control points for the stone filled subgrade,take a road project as an example,expounds the construction technique of the filling stone roadbed from the subgrade construction,subgrade cleaning,slope stone stocking,pavement and filling,and subgrade smoothness,so as to improve the performance of the subgrade.
Soil stabilization with recycled materials improves subgrade performance : research spotlight.
2016-02-29
The use of recycled materials for subgrade stabilization can provide the support needed for construction vehicle loading and more typical long-term traffic loading. This is a particular need in Michigan due to the prevalence of weak subgrade soils. U...
International Nuclear Information System (INIS)
Schwartz, S.E.
1988-10-01
Although it has been recognized for some time that the rate of reactive uptake of gases in cloudwater can depend on the value of the mass-accommodation coefficient (α) describing interfacial mass transport (MT), definitive evaluation of such rates is only now becoming possible with the availability of measurements of α for gases of atmospheric interest at air-water interfaces. Examination of MT limitation to the rate of in-cloud aqueous-phase oxidation of SO 2 by O 3 and H 2 O 2 shows that despite the low value of α/sub O3/ (5 /times/ 10/sup /minus/4/), interfacial MT of this species is not limiting under essentially all conditions of interest; the high values of α for SO 2 (≥ 0.2) and H 2 O 2 (≥ 0.08) indicate no interfacial MT limitation for these species also. Although gas- and aqueous-phase MT can be limiting under certain extremes of conditions, treating the system as under chemical kinetic control is generally an excellent approximation. Interfacial MT limitation also is found not to hinder the rate of H 2 O 2 formation by aqueous-phase disproportionation of HO 2 . Finally, the rapid uptake of N 2 O 5 by cloud droplets implies that the yield of aqueous HNO 3 from in-cloud gas-phase oxidation of NO 2 by O 3 can be substantial even under daytime conditions. This report consists of copies of viewgraphs prepared for this presentation
International Nuclear Information System (INIS)
Ferreri, J. C.; Carmen, A. del
1998-01-01
A numerical study of the dynamics of pattern evolution in reaction-diffusion systems is performed, although limited to one spatial dimension. The diffusion coefficients are nonlinear, based on powers of the scalar variables. The system keeps the dynamics of previous studies in the literature, but the presence of nonlinear diffusion generates a field of strong nonlinear interactions due to the presence of receding travelling waves. This field is limited by the plane of symmetry of the space domain and the last born outgoing travelling wave. These effects are discussed. (author). 10 refs., 7 figs
Determination of the Rate Coefficients of the SO2 plus O plus M yields SO3 plus M Reaction
Hwang, S. M.; Cooke, J. A.; De Witt, K. J.; Rabinowitz, M. J.
2010-01-01
Rate coefficients of the title reaction R(sub 31) (SO2 +O+M yields SO3 +M) and R(sub 56) (SO2 + HO2 yields SO3 +OH), important in the conversion of S(IV) to S(VI),were obtained at T =970-1150 K and rho (sub ave) = 16.2 micro mol/cubic cm behind reflected shock waves by a perturbation method. Shock-heated H2/ O2/Ar mixtures were perturbed by adding small amounts of SO2 (1%, 2%, and 3%) and the OH temporal profiles were then measured using laser absorption spectroscopy. Reaction rate coefficients were elucidated by matching the characteristic reaction times acquired from the individual experimental absorption profiles via simultaneous optimization of k(sub 31) and k(sub 56) values in the reaction modeling (for satisfactory matches to the observed characteristic times, it was necessary to take into account R(sub 56)). In the experimental conditions of this study, R(sub 31) is in the low-pressure limit. The rate coefficient expressions fitted using the combined data of this study and the previous experimental results are k(sub 31,0)/[Ar] = 2.9 10(exp 35) T(exp ?6.0) exp(?4780 K/T ) + 6.1 10(exp 24) T(exp ?3.0) exp(?1980 K/T ) cm(sup 6) mol(exp ?2)/ s at T = 300-2500 K; k(sub 56) = 1.36 10(exp 11) exp(?3420 K/T ) cm(exp 3)/mol/s at T = 970-1150 K. Computer simulations of typical aircraft engine environments, using the reaction mechanism with the above k(sub 31,0) and k(sub 56) expressions, gave the maximum S(IV) to S(VI) conversion yield of ca. 3.5% and 2.5% for the constant density and constant pressure flow condition, respectively. Moreover, maximum conversions occur at rather higher temperatures (?1200 K) than that where the maximum k(sub 31,0) value is located (approximately 800 K). This is because the conversion yield is dependent upon not only the k(sup 31,0) and k(sup 56) values (production flux) but also the availability of H, O, and HO2 in the system (consumption flux).
Radhakrishnan, G.; Anjan Kumar, M.; Raju, G. V. R. Prasada
2017-12-01
Expansive soils are known to be problematic due to their nature and behavior. These soils show volume changes due to changes in moisture content, which cause distortions to structures constructed on them. Relentless efforts are being made all over the world to find solution to the problems of expansive soils. In the case of flexible pavements, unless the subgrade is appropriately treated during the construction stage, the maintenance cost will increase substantially due to deterioration. There are many methods of stabilising expansive subgrade soils. Chemical stabilisation is one such technique employed in improving the engineering properties of the expansive soil. Investigations on chemical stabilization of expansive soils revealed that conventionally used lime could be replaced by the chloride compound chemicals because of their ready dissolvability in water, ease of mixing with soil and supply of sufficient cations for ready cation exchange. The main objective of this work is to study the effectiveness of three chloride compound chemicals, ammonium chloride (NH4Cl), magnesium chloride (MgCl2) and aluminum chloride (AlCl3) on the geotechnical properties of an expansive soil. The chemicals content up to 2% were added to the soil and its effect on the index limits, swell pressure, compaction characteristics as well as California bearing ratio are studied. It was observed that aluminum chloride chemical content has a significantly higher influence than the other two chemicals and it could be recognized as an effective chemical stabilizer.
Transmission Coefficients for Chemical Reactions with Multiple States: Role of Quantum Decoherence
Czech Academy of Sciences Publication Activity Database
de la Lande, A.; Řezáč, Jan; Lévy, B.; Sanders, B. C.; Salahub, D. R.
2011-01-01
Roč. 133, č. 11 (2011), s. 3883-3894 ISSN 0002-7863 Institutional research plan: CEZ:AV0Z40550506 Keywords : decoherence * transition state theory * nonadiabatic reactions Subject RIV: CC - Organic Chemistry Impact factor: 9.907, year: 2011
Shaw, Jacob T.; Lidster, Richard T.; Cryer, Danny R.; Ramirez, Noelia; Whiting, Fiona C.; Boustead, Graham A.; Whalley, Lisa K.; Ingham, Trevor; Rickard, Andrew R.; Dunmore, Rachel E.; Heard, Dwayne E.; Lewis, Ally C.; Carpenter, Lucy J.; Hamilton, Jacqui F.; Dillon, Terry J.
2018-03-01
Gas-phase rate coefficients are fundamental to understanding atmospheric chemistry, yet experimental data are not available for the oxidation reactions of many of the thousands of volatile organic compounds (VOCs) observed in the troposphere. Here, a new experimental method is reported for the simultaneous study of reactions between multiple different VOCs and OH, the most important daytime atmospheric radical oxidant. This technique is based upon established relative rate concepts but has the advantage of a much higher throughput of target VOCs. By evaluating multiple VOCs in each experiment, and through measurement of the depletion in each VOC after reaction with OH, the OH + VOC reaction rate coefficients can be derived. Results from experiments conducted under controlled laboratory conditions were in good agreement with the available literature for the reaction of 19 VOCs, prepared in synthetic gas mixtures, with OH. This approach was used to determine a rate coefficient for the reaction of OH with 2,3-dimethylpent-1-ene for the first time; k = 5.7 (±0.3) × 10-11 cm3 molecule-1 s-1. In addition, a further seven VOCs had only two, or fewer, individual OH rate coefficient measurements available in the literature. The results from this work were in good agreement with those measurements. A similar dataset, at an elevated temperature of 323 (±10) K, was used to determine new OH rate coefficients for 12 aromatic, 5 alkane, 5 alkene and 3 monoterpene VOC + OH reactions. In OH relative reactivity experiments that used ambient air at the University of York, a large number of different VOCs were observed, of which 23 were positively identified. Due to difficulties with detection limits and fully resolving peaks, only 19 OH rate coefficients were derived from these ambient air samples, including 10 reactions for which data were previously unavailable at the elevated reaction temperature of T = 323 (±10) K.
Rate Coefficients for the Reactions of BF with O and O2.
1981-12-21
2 indicate that indi- vidual molecular orbitals of BF are quite asymmetric so that the small overall dipole moment could be misleading. Nevertheless...radiation effects on materials, lu- brication and surface phenomena, thersionic " emision . photosensitive materials and detectors, atomic frequency standards
Mieczkowski, P.; Budziński, B.
2018-05-01
When well performed, pavement renewal or alteration shall ensure the desired properties of the road during the assumed period of operation. Presence of water in the subgrade can be one of the main factors affecting the structural capacity of pavement and can result in cracking of the bituminous layers, even after a very short period of trafficking. Reconstruction of one of regional roads in Poland has been chosen to serve as an example of inappropriate approach to the problem of the presence of water in the road structure. The project included construction of new layers of pavement and increasing the design life of the whole pavement structure to 4.06 million ESAL of 100 kN (as per the Standard Catalogue of Typical Flexible and Semi-rigid Road Pavement Structures, issue of 1997). After a relatively short period of trafficking (3-5 years) localised alligator cracking appeared on the surface along with structural deformations. The pavement condition assessment including FWD tests was carried out to reveal excessive deflections (over 500 μm) which classify the road for renewal. The analysis of data showed that the main cause of distress was softening of the subgrade caused by an ingress of precipitation water under the pavement layers through the roadway and shoulder edges. The deficiencies of the performed reconstruction occurred both in the roadway (including small step-outs in the cement-treated layer) and partly in the shoulders where the existing soil was in places replaced with impervious material, with the existing (cohesive) material left in place on a major part of the overall length.
Saponification reaction system: a detailed mass transfer coefficient determination.
Pečar, Darja; Goršek, Andreja
2015-01-01
The saponification of an aromatic ester with an aqueous sodium hydroxide was studied within a heterogeneous reaction medium in order to determine the overall kinetics of the selected system. The extended thermo-kinetic model was developed compared to the previously used simple one. The reaction rate within a heterogeneous liquid-liquid system incorporates a chemical kinetics term as well as mass transfer between both phases. Chemical rate constant was obtained from experiments within a homogeneous medium, whilst the mass-transfer coefficient was determined separately. The measured thermal profiles were then the bases for determining the overall reaction-rate. This study presents the development of an extended kinetic model for considering mass transfer regarding the saponification of ethyl benzoate with sodium hydroxide within a heterogeneous reaction medium. The time-dependences are presented for the mass transfer coefficient and the interfacial areas at different heterogeneous stages and temperatures. The results indicated an important role of reliable kinetic model, as significant difference in k(L)a product was obtained with extended and simple approach.
Drying shrinkage problems in high PI subgrade soils.
2014-01-01
The main objective of this study was to investigate the longitudinal cracking in pavements due to drying : shrinkage of high PI subgrade soils. The study involved laboartory soil testing and modeling. The : shrinkage cracks usually occur within the v...
Onel, L; Blitz, M A; Seakins, P W
2012-04-05
Monoethanol amine (H2NCH2CH2OH, MEA) has been proposed for large-scale use in carbon capture and storage. We present the first absolute, temperature-dependent determination of the rate coefficient for the reaction of OH with MEA using laser flash photolysis for OH generation, monitoring OH removal by laser-induced fluorescence. The room-temperature rate coefficient is determined to be (7.61 ± 0.76) × 10(-11) cm(3) molecule(-1) s(-1), and the rate coefficient decreases by about 40% by 510 K. The temperature dependence of the rate coefficient is given by k1= (7.73 ± 0.24) × 10(-11)(T/295)(-(0.79±0.11)) cm(3) molecule(-1) s(-1). The high rate coefficient shows that gas-phase processing in the atmosphere will be competitive with uptake onto aerosols.
Directory of Open Access Journals (Sweden)
J. T. Shaw
2018-03-01
Full Text Available Gas-phase rate coefficients are fundamental to understanding atmospheric chemistry, yet experimental data are not available for the oxidation reactions of many of the thousands of volatile organic compounds (VOCs observed in the troposphere. Here, a new experimental method is reported for the simultaneous study of reactions between multiple different VOCs and OH, the most important daytime atmospheric radical oxidant. This technique is based upon established relative rate concepts but has the advantage of a much higher throughput of target VOCs. By evaluating multiple VOCs in each experiment, and through measurement of the depletion in each VOC after reaction with OH, the OH + VOC reaction rate coefficients can be derived. Results from experiments conducted under controlled laboratory conditions were in good agreement with the available literature for the reaction of 19 VOCs, prepared in synthetic gas mixtures, with OH. This approach was used to determine a rate coefficient for the reaction of OH with 2,3-dimethylpent-1-ene for the first time; k = 5.7 (±0.3 × 10−11 cm3 molecule−1 s−1. In addition, a further seven VOCs had only two, or fewer, individual OH rate coefficient measurements available in the literature. The results from this work were in good agreement with those measurements. A similar dataset, at an elevated temperature of 323 (±10 K, was used to determine new OH rate coefficients for 12 aromatic, 5 alkane, 5 alkene and 3 monoterpene VOC + OH reactions. In OH relative reactivity experiments that used ambient air at the University of York, a large number of different VOCs were observed, of which 23 were positively identified. Due to difficulties with detection limits and fully resolving peaks, only 19 OH rate coefficients were derived from these ambient air samples, including 10 reactions for which data were previously unavailable at the elevated reaction temperature of T = 323 (±10 K.
Endres, Eric S; Lakhmanskaya, Olga; Hauser, Daniel; Huber, Stefan E; Best, Thorsten; Kumar, Sunil S; Probst, Michael; Wester, Roland
2014-08-21
In the interstellar medium (ISM) ion–molecule reactions play a key role in forming complex molecules. Since 2006, after the radioastronomical discovery of the first of by now six interstellar anions, interest has grown in understanding the formation and destruction pathways of negative ions in the ISM. Experiments have focused on reactions and photodetachment of the identified negatively charged ions. Hints were found that the reactions of CnH(–) with H2 may proceed with a low (rate [Eichelberger, B.; et al. Astrophys. J. 2007, 667, 1283]. Because of the high abundance of molecular hydrogen in the ISM, a precise knowledge of the reaction rate is needed for a better understanding of the low-temperature chemistry in the ISM. A suitable tool to analyze rare reactions is the 22-pole radiofrequency ion trap. Here, we report on reaction rates for Cn(–) and CnH(–) (n = 2, 4, 6) with buffer gas temperatures of H2 at 12 and 300 K. Our experiments show the absence of these reactions with an upper limit to the rate coefficients between 4 × 10(–16) and 5 × 10(–15) cm(3) s(–1), except for the case of C2(–), which does react with a finite rate with H2 at low temperatures. For the cases of C2H(–) and C4H(–), the experimental results were confirmed with quantum chemical calculations. In addition, the possible influence of a residual reactivity on the abundance of C4H(–) and C6H(–) in the ISM were estimated on the basis of a gas-phase chemical model based on the KIDA database. We found that the simulated ion abundances are already unaffected if reaction rate coefficients with H2 were below 10(–14) cm(3) s(–1).
Hoobler, Ray J.; Leone, Stephen R.
1997-01-01
Rate coefficients for the reactions of C2H + HCN yields products and C2H + CH3CN yields products have been measured over the temperature range 262-360 K. These experiments represent an ongoing effort to accurately measure reaction rate coefficients of the ethynyl radical, C2H, relevant to planetary atmospheres such as those of Jupiter and Saturn and its satellite Titan. Laser photolysis of C2H2 is used to produce C2H, and transient infrared laser absorption is employed to measure the decay of C2H to obtain the subsequent reaction rates in a transverse flow cell. Rate constants for the reaction C2H + HCN yields products are found to increase significantly with increasing temperature and are measured to be (3.9-6.2) x 10(exp 13) cm(exp 3) molecules(exp -1) s(exp -1) over the temperature range of 297-360 K. The rate constants for the reaction C2H + CH3CN yields products are also found to increase substantially with increasing temperature and are measured to be (1.0-2.1) x 10(exp -12) cm(exp 3) molecules(exp -1) s(exp -1) over the temperature range of 262-360 K. For the reaction C2H + HCN yields products, ab initio calculations of transition state structures are used to infer that the major products form via an addition/elimination pathway. The measured rate constants for the reaction of C2H + HCN yields products are significantly smaller than values currently employed in photochemical models of Titan, which will affect the HC3N distribution.
Werfelli, Ghofran; Halvick, Philippe; Honvault, Pascal; Kerkeni, Boutheïna; Stoecklin, Thierry
2015-09-21
The observed abundances of the methylidyne cation, CH(+), in diffuse molecular clouds can be two orders of magnitude higher than the prediction of the standard gas-phase models which, in turn, predict rather well the abundances of neutral CH. It is therefore necessary to investigate all the possible formation and destruction processes of CH(+) in the interstellar medium with the most abundant species H, H2, and e(-). In this work, we address the destruction process of CH(+) by hydrogen abstraction. We report a new calculation of the low temperature rate coefficients for the abstraction reaction, using accurate time-independent quantum scattering and a new high-level ab initio global potential energy surface including a realistic model of the long-range interaction between the reactants H and CH(+). The calculated thermal rate coefficient is in good agreement with the experimental data in the range 50 K-800 K. However, at lower temperatures, the experimental rate coefficient takes exceedingly small values which are not reproduced by the calculated rate coefficient. Instead, the latter rate coefficient is close to the one given by the Langevin capture model, as expected for a reaction involving an ion and a neutral species. Several recent theoretical works have reported a seemingly good agreement with the experiment below 50 K, but an analysis of these works show that they are based on potential energy surfaces with incorrect long-range behavior. The experimental results were explained by a loss of reactivity of the lowest rotational states of the reactant; however, the quantum scattering calculations show the opposite, namely, a reactivity enhancement with rotational excitation.
Pavement Subgrade Performance Study in the Danish Road Testing Machine
DEFF Research Database (Denmark)
Ullidtz, Per; Ertman Larsen, Hans Jørgen
1997-01-01
Most existing pavement subgrade criteria are based on the AASHO Road Test, where only one material was tested and for only one climatic condition. To study the validity of these criteria and to refine the criteria a co-operative research program entitled the "International Pavement Subgrade...... Performance Study" was sponsored by the FHWA with American, Finnish and Danish partners. This paper describes the first test series which was carried out in the Danish Road Testing Machine (RTM).The first step in this program is a full scale test on an instrumented pavement in the Danish Road Testing Machine....... Pressure gauges and strain cells were installed in the upper part of the subgrade, for measuring stresses and strains in all three directions. During and after construction FWD testing was carried out to evaluate the elastic parameters of the materials. These parameters were then used with the theory...
Ng, Maggie; Mok, Daniel K W; Lee, Edmond P F; Dyke, John M
2013-03-15
The minimum energy path (MEP) of the reaction, CF(3)CHFCF(3) + H → transition state (TS) → CF(3)CFCF(3) + H(2), has been computed at different ab initio levels and with density functional theory (DFT) using different functionals. The computed B3LYP/6-31++G**, BH&HLYP/cc-pVDZ, BMK/6-31++G**, M05/6-31+G**, M05-2X/6-31+G**, UMP2/6-31++G**, PUMP2/6-31++G**//UMP2/6-31++G**, RCCSD(T)/aug-cc-pVDZ//UMP2/6-31++G**, RCCSD(T)/aug-cc-pVTZ(spd,sp)//UMP2//6-31++G**, RCCSD(T)/CBS//M05/6-31+G**, and RCCSD(T)/CBS//UMP2/6-31++G** MEPs, and associated gradients and Hessians, were used in reaction rate coefficient calculations based on the transition state theory (TST). Reaction rate coefficients were computed between 300 and 1500 K at various levels of TST, which include conventional TST, canonical variational TST (CVT) and improved CVT (ICVT), and with different tunneling corrections, namely, Wigner, zero-curvature, and small-curvature (SCT). The computed rate coefficients obtained at different ab initio, DFT and TST levels are compared with experimental values available in the 1000-1200 K temperature range. Based on the rate coefficients computed at the ICVT/SCT level, the highest TST level used in this study, the BH&HLYP functional performs best among all the functionals used, while the RCCSD(T)/CBS//MP2/6-31++G** level is the best among all the ab initio levels used. Comparing computed reaction rate coefficients obtained at different levels of theory shows that, the computed barrier height has the strongest effect on the computed reaction rate coefficients as expected. Variational effects on the computed rate coefficients are found to be negligibly small. Although tunneling effects are relatively small at high temperatures (~1500 K), SCT corrections are significant at low temperatures (~300 K), and both barrier heights and the magnitudes of the imaginary frequencies affect SCT corrections. Copyright © 2012 Wiley Periodicals, Inc.
Ng, Maggie; Mok, Daniel K W; Lee, Edmond P F; Dyke, John M
2015-03-21
The reaction between atomic chlorine (Cl) and methyl nitrate (CH3ONO2) is significant in the atmosphere, as Cl is a key oxidant, especially in the marine boundary layer, and alkyl nitrates are important nitrogen-containing organic compounds, which are temporary reservoirs of the reactive nitrogen oxides NO, NO2 and NO3 (NOx). Four reaction channels HCl + CH2ONO2, CH3OCl + NO2, CH3Cl + NO3 and CH3O + ClNO2 were considered. The major channel is found to be the H abstraction channel, to give the products HCl + CH2ONO2. For all channels, geometry optimization and frequency calculations were carried out at the M06-2X/6-31+G** level, while relative electronic energies were improved to the UCCSD(T*)-F12/CBS level. The reaction barrier (ΔE(‡)0K) and reaction enthalpy (ΔH(RX)298K) of the H abstraction channel were computed to be 0.61 and -2.30 kcal mol(-1), respectively, at the UCCSD(T*)-F12/CBS//M06-2X/6-31+G** level. Reaction barriers (ΔE(‡)0K) for the other channels are more positive and these pathways do not contribute to the overall reaction rate coefficient in the temperature range considered (200-400 K). Rate coefficients were calculated for the H-abstraction channel at various levels of variational transition state theory (VTST) including tunnelling. Recommended ICVT/SCT rate coefficients in the temperature range 200-400 K are presented for the first time for this reaction. The values obtained in the 200-300 K region are particularly important as they will be valuable for atmospheric modelling calculations involving reactions with methyl nitrate. The implications of the results to atmospheric chemistry are discussed. Also, the enthalpies of formation, ΔHf,298K, of CH3ONO2 and CH2ONO2 were computed to be -29.7 and 19.3 kcal mol(-1), respectively, at the UCCSD(T*)-F12/CBS level.
Transport Coefficients of Fluids
Eu, Byung Chan
2006-01-01
Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.
Directory of Open Access Journals (Sweden)
Móczár Balázs
2016-06-01
Full Text Available Design and modelling of raft foundations and selecting the value of coefficient of vertical subgrade reaction are still actively discussed topics in geotechnical and structural engineering. In everyday practice, soil–structure interaction is mostly taken into account by using the theory of ‘beam on elastic foundation’, in which the soil is substituted by a certain set of coefficients of subgrade reaction. In this study, finite element analysis of a building was performed using a geotechnical software (Plaxis 3D, which is capable of modelling the subsoil as a continuum, and a structural software (Axis VM, which uses the concept of ‘beam on elastic foundation’. The evaluation of the results and recommendations for everyday engineering practice are introduced in this paper.
Angular distribution coefficients for γ-ray polarization produced in polarized capture reactions
International Nuclear Information System (INIS)
Wulf, E.A.; Guillemette, J.; Weller, H.R.; Seyler, R.G.
1999-01-01
The previous publications have dealt with the angular momentum formalism of both linear and circularly polarized photons in (γ, x) reactions on both polarized and unpolarized targets, and the inverse (capture) reactions initiated by polarized beams. In the present work, utilizing the general formalism of Welton, the authors deal with the linear polarization of the γ-rays which are produced in capture reactions on unpolarized targets, including the possibility of having incident polarized spin 1/2 projectiles. These capture reactions are denoted by a(rvec x, rvec L)c, where rvec x is the incident polarized spin 1/2 projectile and rvec L represents the outgoing polarized γ-ray. They present here the formalism in a convenient form, display a sample table of coefficients, and illustrate its use by means of several examples. A FORTRAN code will be made available for generating similar coefficients for other reactions
Attenuation coefficients of soils
International Nuclear Information System (INIS)
Martini, E.; Naziry, M.J.
1989-01-01
As a prerequisite to the interpretation of gamma-spectrometric in situ measurements of activity concentrations of soil radionuclides the attenuation of 60 to 1332 keV gamma radiation by soil samples varying in water content and density has been investigated. A useful empirical equation could be set up to describe the dependence of the mass attenuation coefficient upon photon energy for soil with a mean water content of 10%, with the results comparing well with data in the literature. The mean density of soil in the GDR was estimated at 1.6 g/cm 3 . This value was used to derive the linear attenuation coefficients, their range of variation being 10%. 7 figs., 5 tabs. (author)
Honvault, P; Scribano, Y
2013-10-03
The dynamics of the D(+) + H2 → HD + H(+) reaction on a recent ab initio potential energy surface (Velilla, L.; Lepetit, B.; Aguado, A.; Beswick, J. A.; Paniagua, M. J. Chem. Phys. 2008, 129, 084307) has been investigated by means of a time-independent quantum mechanical approach. Cross-sections and rate coefficients are calculated, respectively, for collision energies below 0.1 eV and temperatures up to 100 K for astrophysical application. An excellent accord is found for collision energy above 5 meV, while a disagreement between theory and experiment is observed below this energy. We show that the rate coefficients reveal a slightly temperature-dependent behavior in the upper part of the temperature range considered here. This is in agreement with the experimental data above 80 K, which give a temperature independent value. However, a significant decrease is found at temperatures below 20 K. This decrease can be related to quantum effects and the decay back to the reactant channel, which are not considered by simple statistical approaches, such as the Langevin model. Our results have been fitted to appropriate analytical expressions in order to be used in astrochemical and cosmological models.
Pemanfaatan Limbah Pabrik Tekstil (Sludge) Sebagai Penstabil Tanah Lempung untuk Subgrade Jalan
Subarkah, Subarkah
2009-01-01
Soil subgrade has an important role in supporting road pavement construction, especially in establishment of the pavement structure. Swelling characteristic and bearing capacity of the clay soil as a subgrade should be carefully considered in the design to fit the specification. In fact, poor soil such as clay, in some cases, should be replaced by another soil from remote location, or by stabilization of this origin soils to overcome the weakness. In other hand, textile industry has a d...
Evaluation of the effects of enzyme-based liquid chemical stabilizers on subgrade soils
CSIR Research Space (South Africa)
Mgangira, Martin B
2009-07-01
Full Text Available The purpose of this study was to asses the strength of enzyme treated soil material. Thus the aim of the paper is to present laboratory results on the effects of two enzyme-based liquid chemicals as soil stabilizers. Soil samples were prepared...
Effect of geotextile and cement on the performance of sabkha subgrade
Energy Technology Data Exchange (ETDEWEB)
Aiban, S.A.; Al-Ahmadi, H.M.; Siddique, Z.U.; Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Asi, I.M. [Department of Civil Engineering, Hashemite University, Zarqa 13115 (Jordan)
2006-06-15
Many construction and post-construction problems have been reported in the literature when sabkha soils have been used without an understanding of their abnormal behavior, especially their inferior loading capability in their natural conditions. The strength of these soils can be further significantly decreased if the sabkha is soaked. The main objective of this study was to upgrade the load-carrying capacity of pavements constructed on sabkha soils using geotextiles, and to assess the effect of geotextile grade, base thickness, loading type (static and dynamic) and moisture condition (as-molded and soaked) on the performance of soil-fabric-aggregate (SFA) systems. In addition, the sabkha soil was treated with different dosages (5%, 7%, and 10%) of Portland cement and the performance of cement-stabilized sabkha was compared to that of the SFA system under different testing conditions. The ANOVA results indicated that the use of geotextile has a beneficial effect on sabkha soils, especially under wet conditions. Although the improvement in the load-carrying capacity of sabkha samples with high dosages of cement showed better results than the inclusion of geotextile, an economic analysis showed that the use of geotextiles would be superior. Moreover, mechanistic analysis was used to develop a prediction model for the percentage increase in the modulus of resilience. (author)
stabilisation of niger delta fat clay with blend of binders for subgrade
African Journals Online (AJOL)
HOD
Construction of roads on fine-grained soils without any form of stabilisation is a major ... and Portland Cement (PC) to improve its plasticity, California Bearing Ratio (CBR), and swell. .... sand, DCA, lateralite, and cement in stabilising a fat clay.
Directory of Open Access Journals (Sweden)
Jean BERTHIER
2015-08-01
Full Text Available Colorimetric detection of glucose in sample liquids such as human plasma is made by using enzymatic reactions. Either glucose oxidase (GOX or glucose dehydrogenase (GDH can be used to convert glucose. In the multi reactional scheme, the first enzymatic reaction is determinant. We focused here on the study of the enzyme GDH together with the enzymatic cofactor NAD (nicotinamide adenine dinucleotide. This reaction falls in the category of ternary enzymatic reactions. Such reactions depend on four parameters. A method to determine these four parameters is presented in this work, based on a comparison between a series of experiments and the theory. The best values of the parameters are indicated.
Use of soil-steel slag-class-C fly ash mixtures in subgrade applications.
2012-12-07
In Indiana, large quantities of recyclable : materials - such as steel slag, blast furnace : slag and fly ash - are generated each year as : by-products of various industries. Instead of : disposing these by-products into landfills, : we can recycle ...
International Nuclear Information System (INIS)
Smith, A.; Ward, A.; Geldenhuis, S.
1986-01-01
Over the past fifteen years, prodigious efforts and significant advances have been made in methods of prediction of the migration rate of dissolved species in aqueous systems. Despite such work, there remain formidable obstacles in prediction of solute transport in the unsaturated zone over the long time periods necessarily related to the radionuclide bearing wastes. The objective of this paper is to consider the methods, issues and problems with the use of predictive solute transport models for radionuclide migration from nuclear waste disposal in arid environments, if and when engineering containment of the waste fails. Having considered the ability for long term solute prediction for a number of geological environments, the advantages of a disposal environment in which the solute transport process is diffusion controlled will be described
2011-07-01
Additions of byproduct chemicals, such as fly ash or cement kiln dust, have been shown to increase the unconfined compression strength (UCS) of soils. To be considered effective, the soil must exhibit a strength increase of at least 50 psi. Many curr...
Xueying Zhao; Aiqin Shen; Yinchuang Guo; Peng Li; Zhenhua Lv
2017-01-01
It is a consensus that salt heaving and frost heaving are urgent and typical distress in the sulfate saline soil area. To further investigate the microscopic performance of pavement structure in this special area, Jinan-Dongying Freeway in Shandong Province is selected as a case study engineering and the mechanic responses under salt heaving, frost heaving and traffic loads were analyzed through the finite element (FE) Program (ANSYS). In this paper, the process of salt heaving and frost heav...
CSIR Research Space (South Africa)
Anochie-Boateng, Joseph
2010-06-01
Full Text Available properties including friction angle and cohesion for strength properties and shear modulus of the soil at three moisture states. Mohr-Coulomb failure models were developed together with shear modulus correlations for the soil sample. These models can be used...
Burkholder, J. B.; Bernard, F.; Papadimitriou, V. C.
2016-12-01
The atmospheric chemistry of organosiloxanes has recently been implicated in the formation of new particles as well as regional and indoor air quality. Methylsiloxanes with Sitextiles, health care and household products and in industrial applications as solvents and lubricants. They are released into the atmosphere during manufacturing, use, and disposal and have been observed in the atmosphere in ppb levels in certain locations. However, the fundamental chemical properties of this class of compounds, particularly their reactivity with the OH radical, are presently not fully characterized. In this work, the temperature dependence of the rate coefficients for the OH radical reaction with the simplest linear (L2 and L3) and cyclic (D3 and D4) siloxanes were measured: OH + (CH3)3SiOSi(CH3)3 = Products L2OH + [(CH3)3SiO]2Si(CH3)2 = Products L3OH + [-Si(CH3)2O-]3 = Products D3OH + [-Si(CH3)2O-]4 = Products D4OH rate coefficients were measured under pseudo-first conditions in OH over the temperature range 240-370 K using a pulsed laser photolysis-laser induced fluorescence (PLP-LIF) technique and at 296 K using a relative rate method. The present results are compared with available literature data where possible and discrepancies are discussed. The results from this work will be discussed in terms of the atmospheric lifetimes of these methylsiloxanes and the reactivity trends for this class of compound.
Bernard, François; Papanastasiou, Dimitrios K; Papadimitriou, Vassileios C; Burkholder, James B
2018-04-19
Permethylsiloxanes are emitted into the atmosphere during production and use as personal care products, lubricants, and cleaning agents. The predominate atmospheric loss process for permethylsiloxanes is expected to be via gas-phase reaction with the OH radical. In this study, rate coefficients, k(T), for the OH radical gas-phase reaction with the two simplest linear and cyclic permethylsiloxanes were measured using a pulsed laser photolysis-laser induced fluorescence technique over the temperature range of 240-370 K and a relative rate method at 294 K: hexamethyldisiloxane ((CH 3 ) 3 SiOSi(CH 3 ) 3 , L 2 ), k 1 ; octamethyltrisiloxane ([(CH 3 ) 3 SiO] 2 Si(CH 3 ) 2 , L 3 ), k 2 ; hexamethylcyclotrisiloxane ([-Si(CH 3 ) 2 O-] 3 , D 3 ), k 3 ; and octamethylcyclotetrasiloxane ([-Si(CH 3 ) 2 O-] 4 , D 4 ), k 4 . The obtained k(294 K) values and temperature-dependence expressions for the 240-370 K temperature range are (cm 3 molecule -1 s -1 , 2σ absolute uncertainties): k 1 (294 K) = (1.28 ± 0.08) × 10 -12 , k 1 ( T) = (1.87 ± 0.18) × 10 -11 exp(-(791 ± 27)/ T); k 2 (294 K) = (1.72 ± 0.10) × 10 -12 , k 2 ( T) = 1.96 × 10 -13 (T/298) 4.34 exp(657/ T); k 3 (294 K) = (0.82 ± 0.05) × 10 -12 , k 3 ( T) = (1.29 ± 0.19) × 10 -11 exp(-(805 ± 43)/ T); and k 4 (294 K) = (1.12 ± 0.10) × 10 -12 , k 4 ( T) = (1.80 ± 0.26) × 10 -11 exp(-(816 ± 43)/ T). The cyclic molecules were found to be less reactive than the analogous linear molecule with the same number of -CH 3 groups, while the linear and cyclic permethylsiloxane reactivity both increase with the increasing number of CH 3 - groups. The present results are compared with previous rate coefficient determinations where available. The permethylsiloxanes included in this study are atmospherically short-lived compounds with estimated atmospheric lifetimes of 11, 8, 17, and 13 days, respectively.
Rate Coefficients for the OH + (CHO)2 (Glyoxal) Reaction Between 240 and 400 K
Feierabend, K. J.; Talukdar, R. K.; Zhu, L.; Ravishankara, A. R.; Burkholder, J. B.
2006-12-01
Glyoxal (CHO)2, the simplest dialdehyde, is an end product formed in the atmospheric oxidation of biogenic hydrocarbons, for example, isoprene. As such, glyoxal plays a role in regional air quality and ozone production in certain locations. Glyoxal is lost in the atmosphere via UV photolysis and reaction with OH. However, the currently available rate coefficient data for the OH + glyoxal reaction is limited to a single room- temperature measurement made using the relative rate method. A determination of the rate coefficient temperature dependence is therefore needed for a more complete interpretation of the atmospheric processing of glyoxal. This study reports the rate coefficient for the OH + (CHO)2 reaction measured under pseudo- first-order conditions in OH ([(CHO)2] > 1000 [OH]0). OH radicals were produced using 248 nm pulsed laser photolysis of H2O2 or HNO3 and detected by pulsed laser induced fluorescence. The concentration of glyoxal in the reactor was determined using three independent techniques; gas flow rates as well as in situ UV and IR absorption. The total pressure in the reactor was varied from 40 to 300 Torr (He), and the rate coefficient was found to be independent of pressure over the temperature range studied. The rate coefficient exhibits a negative temperature dependence between 240 and 400 K consistent with the dependence previously observed for many other aldehydes. Our room-temperature rate coefficient is smaller than the relative rate value that is currently recommended for use in atmospheric model calculations. Our measured rate coefficients are discussed with respect to those for other aldehydes. The atmospheric implications of our work will also be discussed.
Westeneng, Arnaud C; Rothova, Aniki; de Boer, Joke H; de Groot-Mijnes, Jolanda D F
2007-11-01
To establish the causes of uveitis in immunocompromised patients and to determine the contribution of polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) analysis of aqueous humor in patients with an infectious etiology. Retrospective case series of 56 consecutive immunocompromised patients with uveitis. All patients underwent full ophthalmologic examination and laboratory blood analysis for uveitis. Aqueous humor analyses were performed using PCR and GWC for cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and Toxoplasma gondii. Of 56 immunocompromised patients, 43 (77%), all posterior and panuveitis, had intraocular infections. Twenty-one (49%) had CMV, three (7%) had VZV, 11 (26%) had T. gondii, six (14%) had Treponema pallidum, and one (2%) each had Aspergillus and Candida. In AIDS patients, CMV was the most common cause. A strong correlation between AIDS and ocular syphilis was also observed (P = .007). In nonAIDS immunocompromised patients, T. gondii was most frequently detected. Twenty-seven patients were examined by both PCR and GWC; five (18.5%) were positive by both assays, 15 (55.5%) were positive by PCR alone and seven (26%) by GWC alone. Viral infections were detected by PCR in 16 of 17 (94%) cases; T. gondii in four of 10 (40%) patients. Using GWC, a viral infection was diagnosed in three of 17 (18%) and T. gondii in nine of 10 (90%) cases. In immunocompromised patients, PCR is superior in diagnosing viral infections. Analysis of intraocular antibody production played a decisive role in the diagnosis of ocular toxoplasmosis.
Geogrid reinforced road subgrade influence on the pavement evenness
Šiukščius, A.; Vorobjovas, V.; Vaitkus, A.
2018-05-01
As a result of increasing geogrid reinforcement applications in the road subgrade, there are number of projects where geogrid reinforcement is used to control road pavement evenness when there are small layers of peat or mud deeper under road construction. For this task geogrid reinforcement application is not documented but widely used in Lithuania for over a decade. This paper evaluates the long term influence of the geogrid reinforced soil influence on the road surface evenness, when the organic soils stratify in the deeper layers of the subgrade. The geological conditions of the investigated sections are reviewed. The experiment methodology and test results are described, which leads to the conclusions and insights how the pavement evenness depend on the geological conditions and its enhancement. The question is raised about the need for including this geogrid application to the normative documentation. Explanation of the problems that are encountered and the need for further research is given.
Pavement system with rubber tire chips in subgrade
Energy Technology Data Exchange (ETDEWEB)
Ashtakala, B.; Hoque, A.K.M.M. [Concordia Univ., Montreal, PQ (Canada). Dept. of Civil Engineering
1995-12-31
A pavement design method was developed in which shredded rubber tire chips mixed with sand were used as a material for pavement subgrade. Rubber tire chips are highly compressible and produce both elastic and plastic deformations under the application of loads. Sand was added to fill the void between the tire chips and make the mixture a strong material. The design method considered the vertical compressive strain produced by the design life traffic load 18k (80 KN) repetitions. The equivalent thicknesses of the layers above the subgrade corresponding to this vertical compressive strain were determined using contour charts. From this equivalent thickness, the thicknesses for asphalt pavement, base, and sub-base were determined by Odemark`s method. 3 refs., 1 tab., 3 figs.
A kinetic model for chemical reactions without barriers: transport coefficients and eigenmodes
International Nuclear Information System (INIS)
Alves, Giselle M; Kremer, Gilberto M; Marques, Wilson Jr; Soares, Ana Jacinta
2011-01-01
The kinetic model of the Boltzmann equation proposed in the work of Kremer and Soares 2009 for a binary mixture undergoing chemical reactions of symmetric type which occur without activation energy is revisited here, with the aim of investigating in detail the transport properties of the reactive mixture and the influence of the reaction process on the transport coefficients. Accordingly, the non-equilibrium solutions of the Boltzmann equations are determined through an expansion in Sonine polynomials up to the first order, using the Chapman–Enskog method, in a chemical regime for which the reaction process is close to its final equilibrium state. The non-equilibrium deviations are explicitly calculated for what concerns the thermal–diffusion ratio and coefficients of shear viscosity, diffusion and thermal conductivity. The theoretical and formal analysis developed in the present paper is complemented with some numerical simulations performed for different concentrations of reactants and products of the reaction as well as for both exothermic and endothermic chemical processes. The results reveal that chemical reactions without energy barrier can induce an appreciable influence on the transport properties of the mixture. Oppositely to the case of reactions with activation energy, the coefficients of shear viscosity and thermal conductivity become larger than those of an inert mixture when the reactions are exothermic. An application of the non-barrier model and its detailed transport picture are included in this paper, in order to investigate the dynamics of the local perturbations on the constituent number densities, and velocity and temperature of the whole mixture, induced by spontaneous internal fluctuations. It is shown that for the longitudinal disturbances there exist two hydrodynamic sound modes, one purely diffusive hydrodynamic mode and one kinetic mode
A kinetic model for chemical reactions without barriers: transport coefficients and eigenmodes
Alves, Giselle M.; Kremer, Gilberto M.; Marques, Wilson, Jr.; Jacinta Soares, Ana
2011-03-01
The kinetic model of the Boltzmann equation proposed in the work of Kremer and Soares 2009 for a binary mixture undergoing chemical reactions of symmetric type which occur without activation energy is revisited here, with the aim of investigating in detail the transport properties of the reactive mixture and the influence of the reaction process on the transport coefficients. Accordingly, the non-equilibrium solutions of the Boltzmann equations are determined through an expansion in Sonine polynomials up to the first order, using the Chapman-Enskog method, in a chemical regime for which the reaction process is close to its final equilibrium state. The non-equilibrium deviations are explicitly calculated for what concerns the thermal-diffusion ratio and coefficients of shear viscosity, diffusion and thermal conductivity. The theoretical and formal analysis developed in the present paper is complemented with some numerical simulations performed for different concentrations of reactants and products of the reaction as well as for both exothermic and endothermic chemical processes. The results reveal that chemical reactions without energy barrier can induce an appreciable influence on the transport properties of the mixture. Oppositely to the case of reactions with activation energy, the coefficients of shear viscosity and thermal conductivity become larger than those of an inert mixture when the reactions are exothermic. An application of the non-barrier model and its detailed transport picture are included in this paper, in order to investigate the dynamics of the local perturbations on the constituent number densities, and velocity and temperature of the whole mixture, induced by spontaneous internal fluctuations. It is shown that for the longitudinal disturbances there exist two hydrodynamic sound modes, one purely diffusive hydrodynamic mode and one kinetic mode.
Homayoon, Zahra; Jambrina, Pablo G.; Aoiz, F. Javier; Bowman, Joel M.
2012-07-01
In a previous paper [P. G. Jambrina et al., J. Chem. Phys. 135, 034310 (2011), 10.1063/1.3611400] various calculations of the rate coefficient for the Mu + H2 → MuH + H reaction were presented and compared to experiment. The widely used standard quasiclassical trajectory (QCT) method was shown to overestimate the rate coefficients by several orders of magnitude over the temperature range 200-1000 K. This was attributed to a major failure of that method to describe the correct threshold for the reaction owing to the large difference in zero-point energies (ZPE) of the reactant H2 and product MuH (˜0.32 eV). In this Communication we show that by performing standard QCT calculations for the reverse reaction and then applying detailed balance, the resulting rate coefficient is in very good agreement with the other computational results that respect the ZPE, (as well as with the experiment) but which are more demanding computationally.
Shang, L.; Chou, I-Ming; Lu, W.; Burruss, Robert; Zhang, Y.
2009-01-01
Diffusion coefficients (D) of hydrogen in fused silica capillaries (FSC) were determined between 296 and 523 K by Raman spectroscopy using CO2 as an internal standard. FSC capsules (3.25 × 10−4 m OD, 9.9 × 10−5 m ID, and ∼0.01 m long) containing CO2 and H2were prepared and the initial relative concentrations of hydrogen in these capsules were derived from the Raman peak-height ratios between H2 (near 587 cm−1) and CO2 (near 1387 cm−1). The sample capsules were then heated at a fixed temperature (T) at one atmosphere to let H2 diffuse out of the capsule, and the changes of hydrogen concentration were monitored by Raman spectroscopy after quench. This process was repeated using different heating durations at 296 (room T), 323, 375, 430, 473, and 523 K; the same sample capsule was used repeatedly at each temperature. The values of D (in m2 s−1) in FSC were obtained by fitting the observed changes of hydrogen concentration in the FSC capsule to an equation based on Fick’s law. Our D values are in good agreement with the more recent of the two previously reported experimental data sets, and both can be represented by:lnD=-(16.471±0.035)-44589±139RT(R2=0.99991)">lnD=-(16.471±0.035)-44589±139RT(R2=0.99991)where R is the gas constant (8.3145 J/mol K), T in Kelvin, and errors at 1σ level. The slope corresponds to an activation energy of 44.59 ± 0.14 kJ/mol.The D in FSC determined at 296 K is about an order of magnitude higher than that in platinum at 723 K, indicating that FSC is a suitable membrane for hydrogen at temperature between 673 K and room temperature, and has a great potential for studying redox reactions at these temperatures, especially for systems containing organic material and/or sulphur.
Hintz, Paul A.; Ervin, Kent M.
1994-04-01
Reactions of Ni-n(n=3-10), Pd-n(n=3-8), and Pt-n(n=3-7) with CO are studied in a flow tube reactor. Bimolecular rate coefficients are measured for the association reaction of CO adsorbing on the cluster surface. The rate coefficients range from about 10% of the collision rate for the trimer anions to near the collision rate for clusters larger than four atoms. The maximum number of CO molecules that bind to each cluster is determined. Whereas the saturation limits for nickel are typical for an 18 electron transition metal, the limits for platinum are lower, reflecting the electron deficient structures observed in condensed phase chemistry. The CO saturated palladium clusters represent the first examples of saturated binary palladium carbonyl compounds. Comparisons are made to similar studies on metal cation and neutral clusters and also to surface scattering studies of nickel group metals.
Estimating Reaction Rate Coefficients Within a Travel-Time Modeling Framework
Energy Technology Data Exchange (ETDEWEB)
Gong, R [Georgia Institute of Technology; Lu, C [Georgia Institute of Technology; Luo, Jian [Georgia Institute of Technology; Wu, Wei-min [Stanford University; Cheng, H. [Stanford University; Criddle, Craig [Stanford University; Kitanidis, Peter K. [Stanford University; Gu, Baohua [ORNL; Watson, David B [ORNL; Jardine, Philip M [ORNL; Brooks, Scott C [ORNL
2011-03-01
A generalized, efficient, and practical approach based on the travel-time modeling framework is developed to estimate in situ reaction rate coefficients for groundwater remediation in heterogeneous aquifers. The required information for this approach can be obtained by conducting tracer tests with injection of a mixture of conservative and reactive tracers and measurements of both breakthrough curves (BTCs). The conservative BTC is used to infer the travel-time distribution from the injection point to the observation point. For advection-dominant reactive transport with well-mixed reactive species and a constant travel-time distribution, the reactive BTC is obtained by integrating the solutions to advective-reactive transport over the entire travel-time distribution, and then is used in optimization to determine the in situ reaction rate coefficients. By directly working on the conservative and reactive BTCs, this approach avoids costly aquifer characterization and improves the estimation for transport in heterogeneous aquifers which may not be sufficiently described by traditional mechanistic transport models with constant transport parameters. Simplified schemes are proposed for reactive transport with zero-, first-, nth-order, and Michaelis-Menten reactions. The proposed approach is validated by a reactive transport case in a two-dimensional synthetic heterogeneous aquifer and a field-scale bioremediation experiment conducted at Oak Ridge, Tennessee. The field application indicates that ethanol degradation for U(VI)-bioremediation is better approximated by zero-order reaction kinetics than first-order reaction kinetics.
Directory of Open Access Journals (Sweden)
Wen-hui Zhang
2015-01-01
Full Text Available The feasibility of using water glass and aluminum sulfate to treat high liquid limit soil subgrade diseases is studied through laboratory experiments, and the following results were observed. After improving the high liquid limit clay with water glass and aluminum sulfate, the liquid limit decreases, the plastic limit increases, and the plasticity index decreases. Compared with untreated soil, the clay content of the improved soil decreases, while the silt and coarse contents increase. The absolute and relative expansion rates of the improved soil are both lower than those of the untreated soil. With the same number of dry and wet cycles, the decreased degrees of cohesion and internal friction angle of the improved soil are, respectively, one-half and one-third of those of the untreated soil. After three dry and wet cycles, the California bearing ratio (CBR of the untreated soil does not meet the requirements of specifications. However, after being cured for seven days and being subjected to three dry and wet cycles, the CBR of the improved soil, with 4% water glass solution and 0.4% aluminum sulfate, meets the requirements of specifications.
Measuring of heat transfer coefficient
DEFF Research Database (Denmark)
Henningsen, Poul; Lindegren, Maria
Subtask 3.4 Measuring of heat transfer coefficient Subtask 3.4.1 Design and setting up of tests to measure heat transfer coefficient Objective: Complementary testing methods together with the relevant experimental equipment are to be designed by the two partners involved in order to measure...... the heat transfer coefficient for a wide range of interface conditions in hot and warm forging processes. Subtask 3.4.2 Measurement of heat transfer coefficient The objective of subtask 3.4.2 is to determine heat transfer values for different interface conditions reflecting those typically operating in hot...
Coefficient estimates of negative powers and inverse coefficients for ...
Indian Academy of Sciences (India)
and the inequality is sharp for the inverse of the Koebe function k(z) = z/(1 − z)2. An alternative approach to the inverse coefficient problem for functions in the class S has been investigated by Schaeffer and Spencer [27] and FitzGerald [6]. Although, the inverse coefficient problem for the class S has been completely solved ...
Srinivasulu, G; Bunkan, A J C; Amedro, D; Crowley, J N
2018-01-31
The rate coefficient (k 1 ) for the reaction of OH radicals with perfluoro ethyl vinyl ether (PEVE, C 2 F 5 OCF[double bond, length as m-dash]CF 2 ) has been measured as a function of temperature (T = 207-300 K) using the technique of pulsed laser photolysis with detection of OH by laser-induced fluorescence (PLP-LIF) at pressures of 50 or 100 Torr N 2 bath gas. In addition, the rate coefficient was measured at 298 K and in one atmosphere of air by the relative-rate technique with loss of PEVE and reference reactant monitored in situ by IR absorption spectroscopy. The rate coefficient has a negative temperature dependence which can be parameterized as: k 1 (T) = 6.0 × 10 -13 exp[(480 ± 38/T)] cm 3 molecule -1 s -1 and a room temperature value of k 1 (298 K) = (3.0 ± 0.3) × 10 -12 cm 3 molecule -1 s -1 . Highly accurate rate coefficients from the PLP-LIF experiments were achieved by optical on-line measurements of PEVE and by performing the measurements at two different apparatuses. The large rate coefficient and the temperature dependence indicate that the reaction proceeds via OH addition to the C[double bond, length as m-dash]C double bond, the high pressure limit already being reached at 50 Torr N 2 . Based on the rate coefficient and average OH levels, the atmospheric lifetime of PEVE was estimated to be a few days.
Energy Technology Data Exchange (ETDEWEB)
Yamamoto, K [Soken Chemical and Engineering Co. Ltd., Saitama (Japan); Nishi, K; Kaminoyama, M; Kamiwano, M [Yokohama National University, Yokohama (Japan). Faculty of Engineering
1996-09-10
In radical additional solution polymerization, the viscosity increases with reaction progress. It is important to evaluate beforehand the cooling capacity of the reactor, which worsens with the process. In this study, a stirred batch reactor with both a paddle and a helical screw impeller were studied, and measurements were made for the dynamic changes of the film heat transfer coefficient of the cooling coil with progress of the polymer reaction. We found the change could be evaluated by the calculating heat balance of the generated heat, the viscous dissipation energy and the sensible heat change under conditions of monomer conversion and changing viscosity. 11 refs., 7 figs.
WINKLER'S SINGLE-PARAMETER SUBGRADE MODEL FROM ...
African Journals Online (AJOL)
Preferred Customer
Page 1 ... corresponding single-parameter Winkler model presented in this work. Keywords: Heterogeneous subgrade, Reissner's simplified continuum, Shear interaction, Simplified continuum, Winkler ... model in practical applications and its long time familiarity among practical engineers, its usage has endured to this date ...
Probabilistic optimization of safety coefficients
International Nuclear Information System (INIS)
Marques, M.; Devictor, N.; Magistris, F. de
1999-01-01
This article describes a reliability-based method for the optimization of safety coefficients defined and used in design codes. The purpose of the optimization is to determine the partial safety coefficients which minimize an objective function for sets of components and loading situations covered by a design rule. This objective function is a sum of distances between the reliability of the components designed using the safety coefficients and a target reliability. The advantage of this method is shown on the examples of the reactor vessel, a vapour pipe and the safety injection circuit. (authors)
Jambrina, P. G.; Lara, Manuel; Menéndez, M.; Launay, J.-M.; Aoiz, F. J.
2012-10-01
Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S(1D) + H2 → SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories (SQCT). The calculations have been carried out on the widely used potential energy surface (PES) by Ho et al. [J. Chem. Phys. 116, 4124 (2002), 10.1063/1.1431280] as well as on the recent PES developed by Song et al. [J. Phys. Chem. A 113, 9213 (2009), 10.1021/jp903790h]. The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S(1D).
Energy Technology Data Exchange (ETDEWEB)
Ryu, Si Ok [School of Chemical Engineering, Yeungnam University, Gyeongsan (Korea, Republic of); Shin, Kuan Soo [Dept. of Chemistry, Soongsil University, Seoul (Korea, Republic of); Hwang, Soon Muk [Science Applications International Corp oration, 3000 Aerospace Park way, Brook Park, Ohio (United States)
2017-02-15
Rate coefficients of the title reactions, R1 (CH{sub 4} + O{sub 2} → HO{sub 2}+CH{sub 3}) and R{sub 2} (HCO+O{sub 2} → HO{sub 2} + CO) were obtained over T = 1610 ⁓ 1810 K and T = 200 ⁓ 1760 K, respectively, and at ρ = 7.1 μmol/cm{sup 3}. A lean CH{sub 4}/O{sub 2}/Ar mixture (0.1% CH{sub 4}, ϕ = 0.02) was heated behind reflected shock waves and the temporal OH absorption profiles were measured using a laser absorption spectroscopy. Reaction rate coefficients were elucidated by matching the experimental profiles via optimization of k1 and k2 values in the reaction simulation. The rate coefficient expressions derived are k{sub 1} = 1.46 × 10{sup 14} exp (−26 210 K/T) cm{sup 3}/mol/s, T = 1610 ⁓ 1810 K and k{sub 2} = 1.9 × 10{sup 12} T{sup 0.1{sup 6}} exp (−245 K/T) cm{sup 3}/mol/s, T = 200 ⁓ 1760 K.
Fuel Temperature Coefficient of Reactivity
Energy Technology Data Exchange (ETDEWEB)
Loewe, W.E.
2001-07-31
A method for measuring the fuel temperature coefficient of reactivity in a heterogeneous nuclear reactor is presented. The method, which is used during normal operation, requires that calibrated control rods be oscillated in a special way at a high reactor power level. The value of the fuel temperature coefficient of reactivity is found from the measured flux responses to these oscillations. Application of the method in a Savannah River reactor charged with natural uranium is discussed.
International Nuclear Information System (INIS)
Cristea, G.
1975-01-01
The neutron problems are discussed of the thermonuclear reactor controlled by the rate of the fission reactions. The results obtained by rolling the DTF-4 program in a spherical geometry in the case of an ''external source'' problem permit to draw conclusions concerning the problems of the neutronics system of this thermonuclear reactor type. A relation is deduced for estimating the coefficient of back-reflection of the neutrons within the thermonuclear plasma and the focussion system is discussed of the neutronics of this reactor type
Properties of Traffic Risk Coefficient
Tang, Tie-Qiao; Huang, Hai-Jun; Shang, Hua-Yan; Xue, Yu
2009-10-01
We use the model with the consideration of the traffic interruption probability (Physica A 387(2008)6845) to study the relationship between the traffic risk coefficient and the traffic interruption probability. The analytical and numerical results show that the traffic interruption probability will reduce the traffic risk coefficient and that the reduction is related to the density, which shows that this model can improve traffic security.
Copeland, G; Lee, E P F; Williams, R G; Archibald, A T; Shallcross, D E; Dyke, J M
2014-01-01
In this work, the photolysis rate coefficient of CH3SCH2Cl (MClDMS) in the lower atmosphere has been determined and has been used in a marine boundary layer (MBL) box model to determine the enhancement of SO2 production arising from the reaction DMS + Cl2. Absorption cross sections measured in the 28000-34000 cm(-1) region have been used to determine photolysis rate coefficients of MClDMS in the troposphere at 10 solar zenith angles (SZAs). These have been used to determine the lifetimes of MClDMS in the troposphere. At 0° SZA, a photolysis lifetime of 3-4 h has been obtained. The results show that the photolysis lifetime of MClDMS is significantly smaller than the lifetimes with respect to reaction with OH (≈ 4.6 days) and with Cl atoms (≈ 1.2 days). It has also been shown, using experimentally derived dissociation energies with supporting quantum-chemical calculations, that the dominant photodissocation route of MClDMS is dissociation of the C-S bond to give CH3S and CH2Cl. MBL box modeling calculations show that buildup of MClDMS at night from the Cl2 + DMS reaction leads to enhanced SO2 production during the day. The extra SO2 arises from photolysis of MClDMS to give CH3S and CH2Cl, followed by subsequent oxidation of CH3S.
Analysis of internal conversion coefficients
International Nuclear Information System (INIS)
Coursol, N.; Gorozhankin, V.M.; Yakushev, E.A.; Briancon, C.; Vylov, Ts.
2000-01-01
An extensive database has been assembled that contains the three most widely used sets of calculated internal conversion coefficients (ICC): [Hager R.S., Seltzer E.C., 1968. Internal conversion tables. K-, L-, M-shell Conversion coefficients for Z=30 to Z=103, Nucl. Data Tables A4, 1-237; Band I.M., Trzhaskovskaya M.B., 1978. Tables of gamma-ray internal conversion coefficients for the K-, L- and M-shells, 10≤Z≤104, Special Report of Leningrad Nuclear Physics Institute; Roesel F., Fries H.M., Alder K., Pauli H.C., 1978. Internal conversion coefficients for all atomic shells, At. Data Nucl. Data Tables 21, 91-289] and also includes new Dirac-Fock calculations [Band I.M. and Trzhaskovskaya M.B., 1993. Internal conversion coefficients for low-energy nuclear transitions, At. Data Nucl. Data Tables 55, 43-61]. This database is linked to a computer program to plot ICCs and their combinations (sums and ratios) as a function of Z and energy, as well as relative deviations of ICC or their combinations for any pair of tabulated data. Examples of these analyses are presented for the K-shell and total ICCs of the gamma-ray standards [Hansen H.H., 1985. Evaluation of K-shell and total internal conversion coefficients for some selected nuclear transitions, Eur. Appl. Res. Rept. Nucl. Sci. Tech. 11.6 (4) 777-816] and for the K-shell and total ICCs of high multipolarity transitions (total, K-, L-, M-shells of E3 and M3 and K-shell of M4). Experimental data sets are also compared with the theoretical values of these specific calculations
Global Controllability of Chemical Reactions
Drexler, Dániel András; Tóth, János
2015-01-01
Controllability of chemical reactions is an important problem in chemical engineering science. In control theory, analysis of the controllability of linear systems is well-founded, however the dynamics of chemical reactions is usually nonlinear. Global controllability properties of chemical reactions are analyzed here based on the Lie-algebra of the vector fields associated to elementary reactions. A chemical reaction is controllable almost everywhere if all the reaction rate coefficients can...
Integer Solutions of Binomial Coefficients
Gilbertson, Nicholas J.
2016-01-01
A good formula is like a good story, rich in description, powerful in communication, and eye-opening to readers. The formula presented in this article for determining the coefficients of the binomial expansion of (x + y)n is one such "good read." The beauty of this formula is in its simplicity--both describing a quantitative situation…
Papadimitriou, Vassileios C; Lazarou, Yannis G; Talukdar, Ranajit K; Burkholder, James B
2011-01-20
Rate coefficients, k, for the gas-phase reactions of Cl atoms and NO(3) radicals with 2,3,3,3-tetrafluoropropene, CF(3)CF═CH(2) (HFO-1234yf), and 1,2,3,3,3-pentafluoropropene, (Z)-CF(3)CF═CHF (HFO-1225ye), are reported. Cl-atom rate coefficients were measured in the fall-off region as a function of temperature (220-380 K) and pressure (50-630 Torr; N(2), O(2), and synthetic air) using a relative rate method. The measured rate coefficients are well represented by the fall-off parameters k(0)(T) = 6.5 × 10(-28) (T/300)(-6.9) cm(6) molecule(-2) s(-1) and k(∞)(T) = 7.7 × 10(-11) (T/300)(-0.65) cm(3) molecule(-1) s(-1) for CF(3)CF═CH(2) and k(0)(T) = 3 × 10(-27) (T/300)(-6.5) cm(6) molecule(-2) s(-1) and k(∞)(T) = 4.15 × 10(-11) (T/300)(-0.5) cm(3) molecule(-1) s(-1) for (Z)-CF(3)C═CHF with F(c) = 0.6. Reaction product yields were measured in the presence of O(2) to be (98 ± 7)% for CF(3)C(O)F and (61 ± 4)% for HC(O)Cl in the CF(3)CF═CH(2) reaction and (108 ± 8)% for CF(3)C(O)F and (112 ± 8)% for HC(O)F in the (Z)-CF(3)CF═CHF reaction, where the quoted uncertainties are 2σ (95% confidence level) and include estimated systematic errors. NO(3) reaction rate coefficients were determined using absolute and relative rate methods. Absolute measurements yielded upper limits for both reactions between 233 and 353 K, while the relative rate measurements yielded k(3)(295 K) = (2.6 ± 0.25) × 10(-17) cm(3) molecule(-1) s(-1) and k(4)(295 K) = (4.2 ± 0.5) × 10(-18) cm(3) molecule(-1) s(-1) for CF(3)CF═CH(2) and (Z)-CF(3)CF═CHF, respectively. The Cl-atom reaction with CF(3)CF═CH(2) and (Z)-CF(3)CF═CHF leads to decreases in their atmospheric lifetimes and global warming potentials and formation of a chlorine-containing product, HC(O)Cl, for CF(3)CF═CH(2). The NO(3) reaction has been shown to have a negligible impact on the atmospheric lifetimes of CF(3)CF═CH(2) and (Z)-CF(3)CF═CHF. The energetics for the reaction of Cl, NO(3), and OH with CF
Directory of Open Access Journals (Sweden)
Betha Ika Wilistien
2017-03-01
Full Text Available The objective of this research is to determine the influential proportion of sweet potato Subgrade frozen usage as the substitution material toward the production of an extract product snack by using corn grits and rice. The parameters examined were organoleptic characteristic and proper analysis of financial. The organoleptic analysis comprises taste, crispiness, appearance, color, and aroma. The chemical analysis includes sucrose, water, and essence, as well as protein content. The result of this research shows that organoleptic testing toward the taste of an extract product snack by using Beni azzuma sweet potato subgrade indicates that the combination treatments give a positive influence toward organoleptic characteristics of the product. An extract product of snack product from Beni azzuma sweet potato Subgrade as the substitution material with 95% rice formula and 5% Beni azzuma sweet potato Subgrade is chosen as the best product for having the highest weight or quality, 0.970. Proper analysis from the snack processing is shown by NPV score, Rp. 2.,016,418,748 (bigger than zero, the IRR score is 50.00% (bigger than deposit interest, 12.56%. The investment expense needed for constructing the unit of an extract product snack processing with Beni azzuma sweet potato Subgrade as the substitution material is Rp. 330,978,230. The investment will be back after 3 years 5 months, and every year the project can give the profit of 50% from the investment expense.
Extinction Coefficient of Gold Nanostars
de Puig, Helena; Tam, Justina O.; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly
2015-01-01
Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 108 to 26.8 × 108 M−1cm−1. Measured values correl...
Study of transport coefficients of nanodiamond nanofluids
Pryazhnikov, M. I.; Minakov, A. V.; Guzei, D. V.
2017-09-01
Experimental data on the thermal conductivity coefficient and viscosity coefficient of nanodiamond nanofluids are presented. Distilled water and ethylene glycol were used as the base fluid. Dependences of transport coefficients on concentration are obtained. It was shown that the thermal conductivity coefficient increases with increasing nanodiamonds concentration. It was shown that base fluids properties and nanodiamonds concentration affect on the rheology of nanofluids.
Form of multicomponent Fickian diffusion coefficients matrix
International Nuclear Information System (INIS)
Wambui Mutoru, J.; Firoozabadi, Abbas
2011-01-01
Highlights: → Irreversible thermodynamics establishes form of multicomponent diffusion coefficients. → Phenomenological coefficients and thermodynamic factors affect sign of diffusion coefficients. → Negative diagonal elements of diffusion coefficients matrix can occur in non-ideal mixtures. → Eigenvalues of the matrix of Fickian diffusion coefficients may not be all real. - Abstract: The form of multicomponent Fickian diffusion coefficients matrix in thermodynamically stable mixtures is established based on the form of phenomenological coefficients and thermodynamic factors. While phenomenological coefficients form a symmetric positive definite matrix, the determinant of thermodynamic factors matrix is positive. As a result, the Fickian diffusion coefficients matrix has a positive determinant, but its elements - including diagonal elements - can be negative. Comprehensive survey of reported diffusion coefficients data for ternary and quaternary mixtures, confirms that invariably the determinant of the Fickian diffusion coefficients matrix is positive.
Evaluation of Rock Joint Coefficients
Audy, Ondřej; Ficker, Tomáš
2017-10-01
A computer method for evaluation of rock joint coefficients is described and several applications are presented. The method is based on two absolute numerical indicators that are formed by means of the Fourier replicas of rock joint profiles. The first indicator quantifies the vertical depth of profiles and the second indicator classifies wavy character of profiles. The absolute indicators have replaced the formerly used relative indicators that showed some artificial behavior in some cases. This contribution is focused on practical computations testing the functionality of the newly introduced indicators.
Czech Academy of Sciences Publication Activity Database
McCleskey, M.; Mukhamedzhanov, A. M.; Trache, L.; Tribble, R. E.; Banu, A.; Eremenko, V.; Goldberg, V. Z.; Lui, Y. W.; McCleskey, E.; Roeder, B. T.; Spiridon, A.; Carstoiu, F.; Burjan, Václav; Hons, Zdeněk; Thompson, I. J.
2014-01-01
Roč. 89, č. 4 (2014), 044605 ISSN 0556-2813 R&D Projects: GA MŠk(CZ) LH11001 Institutional support: RVO:61389005 Keywords : capture reactions * cross-section * asymptotic normalization coefficient Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.733, year: 2014
International Nuclear Information System (INIS)
Tone, Tatsuzo
1978-07-01
Described are the reactivity coefficient of D-T fusion reaction, slowing-down processes of deuterons injected with high energy and 3.52 MeV alpha particles generated in D-T reaction, and the power balance in a Tokamak reactor plasma. Most of the results were obtained in the first preliminary design of JAERI Experimental Fusion Reactor (JXFR) driven with stationary neutral beam injection. A manual of numerical computation program ''BALTOK'' developed for the calculations is given in the appendix. (auth.)
Extinction Coefficient of Gold Nanostars.
de Puig, Helena; Tam, Justina O; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly
2015-07-30
Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 10 8 to 26.8 × 10 8 M -1 cm -1 . Measured values correlate with those obtained from theoretical models of the NStars using the discrete dipole approximation (DDA), which we use to simulate the extinction spectra of the nanostars. Finally, because NStars are typically used in biological applications, we conjugate DNA and antibodies to the NStars and calculate the footprint of the bound biomolecules.
1989-05-01
size, gradation, reactivity , plasticity index, pH concentration, degree of drainage, ratio of calcium to magnesium ions, ratio of silica to...many were proprietary. The best of stabilizers include Quaternary amines, AM-9 chemical grout, phosphoric acid, lignin and cellulose derivatives, sodium...strong or weak alkalies . It is soluble in aromatic and chlorinated hydrocarbons, a strong negative factor to be considered in its candidacy as a
Dateo, Christopher E.; Walch, Stephen P.
2002-01-01
As part of NASA Ames Research Center's Integrated Process Team on Device/Process Modeling and Nanotechnology our goal is to create/contribute to a gas-phase chemical database for use in modeling microelectronics devices. In particular, we use ab initio methods to determine chemical reaction pathways and to evaluate reaction rate coefficients. Our initial studies concern reactions involved in the dichlorosilane-hydrogen (SiCl2H2--H2) and trichlorosilane-hydrogen (SiCl2H-H2) systems. Reactant, saddle point (transition state), and product geometries and their vibrational harmonic frequencies are determined using the complete-active-space self-consistent-field (CASSCF) electronic structure method with the correlation consistent polarized valence double-zeta basis set (cc-pVDZ). Reaction pathways are constructed by following the imaginary frequency mode of the saddle point to both the reactant and product. Accurate energetics are determined using the singles and doubles coupled-cluster method that includes a perturbational estimate of the effects of connected triple excitations (CCSD(T)) extrapolated to the complete basis set limit. Using the data from the electronic structure calculations, reaction rate coefficients are obtained using conventional and variational transition state and RRKM theories.
Energy Technology Data Exchange (ETDEWEB)
Clajus, M.; Albert, J.; Bruno, M.; Egun, P.M.; Glockle, W.; Glombik, A.; Gruebler, W.; Hautle, P.; Kretschmer, W.; Rauscher, A.; Schmelzbach, P.A.; Slaus, I.; Weidmann, R.; Witala, H. [Inst. fuer Mittelenergiephys., Eidgenoessische Tech. Hochschule, Zurich (Switzerland)
1995-10-01
The polarization transfer coefficients K{sub x}{sup x}', K{sub y}{sup y}' and K{sub z}{sup x}' in the reaction {sup 2}H(p,p){sup 2}H have been measured at an incident proton energy of 22.5 MeV. The results are compared to predictions from Faddeev calculations using various nucleon-nucleon potential models. The overall agreement is rather good. The comparison in more detail shows a pronounced sensitivity of the results, especially for K{sub y}{sup y}', to the {sup 3}S{sub 1}-{sup 3}D{sub 1} and {sup 1}P{sub 1} NN force components. As in nucleon-nucleon scattering, however, these two parameters are correlated, thus hampering definite conclusions. (author)
Factorization of Transport Coefficients in Macroporous Media
DEFF Research Database (Denmark)
Shapiro, Alexander; Stenby, Erling Halfdan
2000-01-01
We prove the fundamental theorem about factorization of the phenomenological coefficients for transport in macroporous media. By factorization we mean the representation of the transport coefficients as products of geometric parameters of the porous medium and the parameters characteristic...
Mauzerall, David; Hou, Jian-Min; Boichenko, Vladimir A
2002-01-01
Photoacoustics (PA) allows the determination of enthalpy and volume changes of photoreactions in photosynthetic reaction centers on the 0.1-10 mus time scale. These include the bacterial centers from Rb. sphaeroides, PS I and PS II centers from Synechocystis and in whole cells. In vitro and in vivo PA data on PS I and PS II revealed that both the volume change (-26 A(3)) and reaction enthalpy (-0.4 eV) in PS I are the same as those in the bacterial centers. However the volume change in PS II is small and the enthalpy far larger, -1 eV. Assigning the volume changes to electrostriction allows a coherent explanation of these observations. One can explain the large volume decrease in the bacterial centers with an effective dielectric coefficient of approximately 4. This is a unique approach to this parameter so important in estimation of protein energetics. The value of the volume contraction for PS I can only be explained if the acceptor is the super- cluster (Fe(4)S(4))(Cys(4)) with charge change from -1 to -2. The small volume change in PS II is explained by sub-mus electron transfer from Y(Z) anion to P(680) cation, in which charge is only moved from the Y(Z) anion to the Q(A) with no charge separation or with rapid proton transfer from oxidized Y(Z) to a polar region and thus very little change in electrostriction. At more acid pH equally rapid proton transfer from a neighboring histidine to a polar region may be caused by the electric field of the P(680) cation.
Apparatus for measurement of coefficient of friction
Slifka, A. J.; Siegwarth, J. D.; Sparks, L. L.; Chaudhuri, Dilip K.
1990-01-01
An apparatus designed to measure the coefficient of friction in certain controlled atmospheres is described. The coefficient of friction observed during high-load tests was nearly constant, with an average value of 0.56. This value is in general agreement with that found in the literature and also with the initial friction coefficient value of 0.67 measured during self-mated friction of 440C steel in an oxygen environment.
Determination of absolute internal conversion coefficients using the SAGE spectrometer
Energy Technology Data Exchange (ETDEWEB)
Sorri, J., E-mail: juha.m.t.sorri@jyu.fi [University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla (Finland); Greenlees, P.T.; Papadakis, P.; Konki, J. [University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla (Finland); Cox, D.M. [University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla (Finland); Department of Physics, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Auranen, K.; Partanen, J.; Sandzelius, M.; Pakarinen, J.; Rahkila, P.; Uusitalo, J. [University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla (Finland); Herzberg, R.-D. [Department of Physics, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Smallcombe, J.; Davies, P.J.; Barton, C.J.; Jenkins, D.G. [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)
2016-03-11
A non-reference based method to determine internal conversion coefficients using the SAGE spectrometer is carried out for transitions in the nuclei of {sup 154}Sm, {sup 152}Sm and {sup 166}Yb. The Normalised-Peak-to-Gamma method is in general an efficient tool to extract internal conversion coefficients. However, in many cases the required well-known reference transitions are not available. The data analysis steps required to determine absolute internal conversion coefficients with the SAGE spectrometer are presented. In addition, several background suppression methods are introduced and an example of how ancillary detectors can be used to select specific reaction products is given. The results obtained for ground-state band E2 transitions show that the absolute internal conversion coefficients can be extracted using the methods described with a reasonable accuracy. In some cases of less intense transitions only an upper limit for the internal conversion coefficient could be given.
Determination of absolute internal conversion coefficients using the SAGE spectrometer
International Nuclear Information System (INIS)
Sorri, J.; Greenlees, P.T.; Papadakis, P.; Konki, J.; Cox, D.M.; Auranen, K.; Partanen, J.; Sandzelius, M.; Pakarinen, J.; Rahkila, P.; Uusitalo, J.; Herzberg, R.-D.; Smallcombe, J.; Davies, P.J.; Barton, C.J.; Jenkins, D.G.
2016-01-01
A non-reference based method to determine internal conversion coefficients using the SAGE spectrometer is carried out for transitions in the nuclei of "1"5"4Sm, "1"5"2Sm and "1"6"6Yb. The Normalised-Peak-to-Gamma method is in general an efficient tool to extract internal conversion coefficients. However, in many cases the required well-known reference transitions are not available. The data analysis steps required to determine absolute internal conversion coefficients with the SAGE spectrometer are presented. In addition, several background suppression methods are introduced and an example of how ancillary detectors can be used to select specific reaction products is given. The results obtained for ground-state band E2 transitions show that the absolute internal conversion coefficients can be extracted using the methods described with a reasonable accuracy. In some cases of less intense transitions only an upper limit for the internal conversion coefficient could be given.
Determination of the diffusion coefficient of hydrogen ion in hydrogels.
Schuszter, Gábor; Gehér-Herczegh, Tünde; Szűcs, Árpád; Tóth, Ágota; Horváth, Dezső
2017-05-17
The role of diffusion in chemical pattern formation has been widely studied due to the great diversity of patterns emerging in reaction-diffusion systems, particularly in H + -autocatalytic reactions where hydrogels are applied to avoid convection. A custom-made conductometric cell is designed to measure the effective diffusion coefficient of a pair of strong electrolytes containing sodium ions or hydrogen ions with a common anion. This together with the individual diffusion coefficient for sodium ions, obtained from PFGSE-NMR spectroscopy, allows the determination of the diffusion coefficient of hydrogen ions in hydrogels. Numerical calculations are also performed to study the behavior of a diffusion-migration model describing ionic diffusion in our system. The method we present for one particular case may be extended for various hydrogels and diffusing ions (such as hydroxide) which are relevant e.g. for the development of pH-regulated self-healing mechanisms and hydrogels used for drug delivery.
New definition of the cell diffusion coefficient
International Nuclear Information System (INIS)
Koehler, P.
1975-01-01
As was shown in a recent work by Gelbard, the usually applied Benoist definition of the cell diffusion coefficient gives two different values if two different definitions of the cell are made. A new definition is proposed that preserves the neutron balance for the homogenized lattice and that is independent of the cell definition. The resulting diffusion coefficient is identical with the main term of Benoist's diffusion coefficient
Energy Technology Data Exchange (ETDEWEB)
Lagana, Antonio; Faginas Lago, Noelia; Rampino, Sergio [Dipartimento di Chimica, Universita di Perugia, 06123 Perugia (Italy); Huarte-Larranaga, FermIn [Computer Simulation and Modeling Lab (CoSMoLab), Parc CientIfic de Barcelona, 08028 Barcelona (Spain); GarcIa, Ernesto [Departamento de Quimica Fisica, Universidad del PaIs Vasco, 01006 Vitoria (Spain)], E-mail: lagana05@gmail.com, E-mail: fhuarte@pcb.ub.es, E-mail: e.garcia@ehu.es
2008-10-15
Zero total angular momentum exact quantum calculations of the probabilities of the N+N{sub 2} reaction have been performed on the L3 potential energy surface having a bent transition state. This has allowed us to work out J-shifting estimates of the thermal rate coefficient based on the calculation of either detailed (state-to-state) or cumulative (multiconfiguration) probabilities. The results obtained are used to compare the numerical outcomes and the concurrent computational machineries of both quantum and semiclassical approaches as well as to exploit the potentialities of the J-shifting model. The implications of moving the barrier to reaction from the previously proposed collinear geometry of the LEPS to the bent one of L3 are also investigated by comparing the related detailed reactive probabilities.
A paradox: The thermal rate coefficient for the H+DCl → HCl+D exchange reaction
International Nuclear Information System (INIS)
Thompson, D.L.; Suzukawa, H.H. Jr.; Raff, L.M.
1975-01-01
Previously reported photolysis experiments indicate that the frequency factors associated with the hydrogen-exchange reactions H+DCl → HCl+D and D+HCl → DCl+H are on the order of 10 10 cm 3 /molcenter-dotsec. A series of unadjusted, quasiclassical trajectory calculations were been carried out to compute the thermal rate coefficients and activation parameters for a series of 13 thermal processes of the type A+BC → AB+C, where A=H, D, or Cl and BC=H 2 , D 2 , HCl, DCl, or Cl 2 . In addition, hot-atom yield ratios have been computed from the IRP equation for the reactions D*+DCl → D 2 +Cl, D*+Cl 2 → DCl + Cl as a function of the initial D* laboratory energy. The computations yield (1) hot-atom DCl/D 2 yield ratios within a factor of 2 of the experimental values; (2) thermal activation energies in satisfactory agreement with experiment for all processes investigated; and (3) frequency factors in reasonable accord with experiment for all the reactions except the hydrogen exchange reactions
Diffusion coefficients of paracetamol in aqueous solutions
International Nuclear Information System (INIS)
Ribeiro, Ana C.F.; Barros, Marisa C.F.; Veríssimo, Luís M.P.; Santos, Cecilia I.A.V.; Cabral, Ana M.T.D.P.V.; Gaspar, Gualter D.; Esteso, Miguel A.
2012-01-01
Highlights: ► Mutual diffusion coefficients of paracetamol in aqueous dilute solutions. ► Influence of the thermodynamic factors on the variation of their mutual diffusion coefficients. ► Estimation of the mutual limiting diffusion coefficients of the molecular, D m 0 , and ionized forms, D ± 0 , of this drug. - Abstract: Binary mutual diffusion coefficients measured by the Taylor dispersion method, for aqueous solutions of paracetamol (PA) at concentrations from (0.001 to 0.050) mol·dm −3 at T = 298.15 K, are reported. From the Nernst–Hartley equation and our experimental results, the limiting diffusion coefficient of this drug and its thermodynamic factors are estimated, thereby contributing in this way to a better understanding of the structure of such systems and of their thermodynamic behaviour in aqueous solution at different concentrations.
Determination of the surface drag coefficient
DEFF Research Database (Denmark)
Mahrt, L.; Vickers, D.; Sun, J.L.
2001-01-01
This study examines the dependence of the surface drag coefficient on stability, wind speed, mesoscale modulation of the turbulent flux and method of calculation of the drag coefficient. Data sets over grassland, sparse grass, heather and two forest sites are analyzed. For significantly unstable...... conditions, the drag coefficient does not depend systematically on z/L but decreases with wind speed for fixed intervals of z/L, where L is the Obukhov length. Even though the drag coefficient for weak wind conditions is sensitive to the exact method of calculation and choice of averaging time, the decrease...... of the drag coefficient with wind speed occurs for all of the calculation methods. A classification of flux calculation methods is constructed, which unifies the most common previous approaches. The roughness length corresponding to the usual Monin-Obukhov stability functions decreases with increasing wind...
Meta-Analysis of Coefficient Alpha
Rodriguez, Michael C.; Maeda, Yukiko
2006-01-01
The meta-analysis of coefficient alpha across many studies is becoming more common in psychology by a methodology labeled reliability generalization. Existing reliability generalization studies have not used the sampling distribution of coefficient alpha for precision weighting and other common meta-analytic procedures. A framework is provided for…
Estimation of the simple correlation coefficient.
Shieh, Gwowen
2010-11-01
This article investigates some unfamiliar properties of the Pearson product-moment correlation coefficient for the estimation of simple correlation coefficient. Although Pearson's r is biased, except for limited situations, and the minimum variance unbiased estimator has been proposed in the literature, researchers routinely employ the sample correlation coefficient in their practical applications, because of its simplicity and popularity. In order to support such practice, this study examines the mean squared errors of r and several prominent formulas. The results reveal specific situations in which the sample correlation coefficient performs better than the unbiased and nearly unbiased estimators, facilitating recommendation of r as an effect size index for the strength of linear association between two variables. In addition, related issues of estimating the squared simple correlation coefficient are also considered.
Implications of NGA for NEHRP site coefficients
Borcherdt, Roger D.
2012-01-01
Three proposals are provided to update tables 11.4-1 and 11.4-2 of Minimum Design Loads for Buildings and Other Structures (7-10), by the American Society of Civil Engineers (2010) (ASCE/SEI 7-10), with site coefficients implied directly by NGA (Next Generation Attenuation) ground motion prediction equations (GMPEs). Proposals include a recommendation to use straight-line interpolation to infer site coefficients at intermediate values of ̅vs (average shear velocity). Site coefficients are recommended to ensure consistency with ASCE/SEI 7-10 MCER (Maximum Considered Earthquake) seismic-design maps and simplified site-specific design spectra procedures requiring site classes with associated tabulated site coefficients and a reference site class with unity site coefficients. Recommended site coefficients are confirmed by independent observations of average site amplification coefficients inferred with respect to an average ground condition consistent with that used for the MCER maps. The NGA coefficients recommended for consideration are implied directly by the NGA GMPEs and do not require introduction of additional models.
Li, Jun; Guo, Hua
2018-03-15
Thermal rate coefficients for the title reaction and its various isotopologues are computed using a tunneling-corrected transition-state theory on a global potential energy surface recently developed by fitting a large number of high-level ab initio points. The calculated rate coefficients are found to agree well with the measured ones in a wide temperature range, validating the accuracy of the potential energy surface. Strong non-Arrhenius effects are found at low temperatures. In addition, the calculations reproduced the primary and secondary kinetic isotope effects. These results confirm the strong influence of tunneling to this heavy-light-heavy hydrogen abstraction reaction.
Energy Technology Data Exchange (ETDEWEB)
Takebe, Shinichi; Abe, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
2001-03-01
The distribution coefficient is very important parameter for environmental impact assessment on the disposal of radioactive waste arising from research institutes. The literature survey in the country was mainly carried out for the purpose of selecting the reasonable distribution coefficient value on the utilization of this value in the safety evaluation. This report was arranged much informations on the distribution coefficient for inputting to the database for each literature, and was summarized as a literature information data on the distribution coefficient. (author)
Analysis of flow coefficient in chair manufacture
Ivković Dragoljub; Živković Slaven
2005-01-01
The delivery on time is not possible without the good-quality planning of deadlines, i.e. planning of the manufacturing process duration. The study of flow coefficient enables the realistic forecasting of the manufacturing process duration. This paper points to the significance of the study of flow coefficient on scientific basis so as to determine the terms of the end of the manufacture of chairs made of sawn timber. Chairs are the products of complex construction, often almost completely ma...
Experimental techniques of conversion coefficient measurements
International Nuclear Information System (INIS)
Hamilton, J.H.
1975-01-01
Discusses briefly the history of conversion electron spectra measurements, and the interpretation of the collected data. Then provides a comprehensive review of techniques presently available to measure the conversion coefficients. (Auth.)
Form coefficient of helical toroidal solenoids
International Nuclear Information System (INIS)
Amelin, V.Z.; Kunchenko, V.B.
1982-01-01
For toroidal solenoids with continuous spiral coil, winded according to the laws of equiinclined and simple cylindrical spirals with homogeneous, linearly increasing to the coil periphery and ''Bitter'' distribution of current density, the analytical expressions for the dependence between capacity consumed and generated magnetic field, expressions for coefficients of form similar to Fabry coefficient for cylindrical solenoids are obtained and dependence of the form coefficient and relative volume of solenoid conductor on the number of revolutions of screw line per one circumvention over the large torus radius is also investigated. Analytical expressions of form coefficients and graphical material permit to select the optimum geometry as to capacity consumed both for spiral (including ''force-free'') and conventional toroidal solenoids of magnetic systems in thermonulear installations
Diffusion Coefficients of Several Aqueous Alkanolamine Solutions
Snijder, Erwin D.; Riele, Marcel J.M. te; Versteeg, Geert F.; Swaaij, W.P.M. van
1993-01-01
The Taylor dispersion technique was applied for the determination of diffusion coefficients of various systems. Experiments with the system KCl in water showed that the experimental setup provides accurate data. For the alkanolamines monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine
Heat transfer coefficient of cryotop during freezing.
Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J
2013-01-01
Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K).
Definition of global dispersion coefficients
International Nuclear Information System (INIS)
Naff, R.L.
1983-10-01
For estimation of a global longitudinal dispersivity at the Gorleben site, data available primarily consist of suites of geophysical logs from wells penetrating the Quaternary aquifer. A length scale for the principle aquifer at Gorleben is to be found. Samples are to be taken separately to estimate the variance in hydraulic conductivity (Taylor Analysis, Fickian dispersion process). (DG)
Investigation of photon attenuation coefficients for marble
International Nuclear Information System (INIS)
Basyigit, C; Akkurt, I; Kilincarslan, S; Akkurt, A
2005-01-01
The total linear attenuation coefficients μ (cm -1 ) have been obtained using the XCOM program at photon energies of 1 keV to 1 GeV for six different natural marbles produced in different places in Turkey. The individual contribution of photon interaction processes to the total linear attenuation coefficients for marble has been investigated. The calculated results were also compared with the measurements. The results obtained for marble were also compared with concrete. (note)
Reactions of stabilized Criegee Intermediates
Vereecken, Luc; Harder, Hartwig; Novelli, Anna
2014-05-01
Carbonyl oxides (Criegee intermediates) were proposed as key intermediates in the gas phase ozonolysis of alkenes in 1975 by Rudolf Criegee. Despite the importance of ozonolysis in atmospheric chemistry, direct observation of these intermediates remained elusive, with only indirect experimental evidence for their role in the oxidation of hydrocarbons, e.g. through scavenging experiments. Direct experimental observation of stabilized CI has only been achieved since 2008. Since then, a concerted effort using experimental and theoretical means is in motion to characterize the chemistry and kinetics of these reactive intermediates. We present the results of theoretical investigations of the chemistry of Criegee intermediates with a series of coreactants which may be of importance in the atmosphere, in experimental setups, or both. This includes the CI+CI cross-reaction, which proceeds with a rate coefficient near the collision limit and can be important in experimental conditions. The CI + alkene reactions show strong dependence of the rate coefficient depending on the coreactants, but is generally found to be rather slow. The CI + ozone reaction is sufficiently fast to occur both in experiment and the free troposphere, and acts as a sink for CI. The reaction of CI with hydroperoxides, ROOH, is complex, and leads both to the formation of oligomers, as to the formation of reactive etheroxides, with a moderately fast rate coefficient. The importance of these reactions is placed in the context of the reaction conditions in different atmospheric environments ranging from unpolluted to highly polluted.
International Nuclear Information System (INIS)
Raynal, J.
1976-01-01
Closed formulae and recurrence relations for the transformation of a two-body harmonic oscillator wave function to the hyperspherical formalism are given. With them Moshinsky or Smirnov coefficients are obtained from the transformation coefficients of hyperspheric harmonics. For these coefficients the diagonalization method of Talman and Lande reduces to simple recurrence relations which can be used directly to compute them. New closed formulae for these coefficients are also derived: they are needed to compute the two simplest coefficients which determine the sign for the recurrence relation. (Auth.)
Directory of Open Access Journals (Sweden)
Jorge I. Villa
2017-01-01
Full Text Available By using the solid state reaction method samples of Ca1-xLaxMnO3 (0 ≤ x ≥ 0.15 were prepared. Their transport properties were studied by electrical resistivity rho(T and Seebeck coefficient S(T measurements as a function of temperature and lanthanum content, in the temperature range between 100 and 290K. The structural and morphological properties were studied by X-ray diffraction analysis (XRD and scanning electron microscopy (SEM, respectively. The Seebeck coefficient is negative throughout the studied temperature range indicating a conduction given by negative charge carriers, its magnitude decreases with the lanthanum content from |-261| mV/K to |-120| mV/K. The electrical resistivity shows a semiconducting behavior, it was interpreted in terms of small polaron hopping model. Thermoelectric properties of the obtained compounds were studied by the thermoelectric power factor PF, which reaches maximum values around 2mW/K2cm, these values become this kind of ceramics promising thermoelectric compound, to be used in technological applications.
Formulas for activity coefficients of individual ions
Ritsema, C.J.; Bloemer, F.
1986-01-01
For chemical calculations with gaseous equilibria and for non-ionic reactions in solution one can calculate in terms of concentrations to a fairly good approximation. However, in dealing with ionic reactions, with certain aspects of kinetics in solution, and with elcetromotive force studies,
Experimental determination of fission gas adsorption coefficients
International Nuclear Information System (INIS)
Lovell, R.; Underhill, D.W.
1979-01-01
Large charcoal beds have been used for a number of years for the holdup and decay of radioactive isotopes of krypton and xenon. Reliable design of these beds depends on an accurate knowledge of the adsorption coefficient of krypton and xenon on the adsorbents used in these beds. It is somewhat surprising that there is no standard procedure of determining the adsorption coefficient for krypton and xenon. Fundamental information needed to establish a standardized reproducible test procedure is given emphasizing the breakthrough curves commonly used to analyze dynamic adsorption data can lead to serious systematic errors and the fact that the adsorption coefficient, if calculated from the arithmetic holding time, is independent of geometric factors such as the shape of the adsorption bed and the irregular shape of the adsorbent
Curvature of Indoor Sensor Network: Clustering Coefficient
Directory of Open Access Journals (Sweden)
2009-03-01
Full Text Available We investigate the geometric properties of the communication graph in realistic low-power wireless networks. In particular, we explore the concept of the curvature of a wireless network via the clustering coefficient. Clustering coefficient analysis is a computationally simplified, semilocal approach, which nevertheless captures such a large-scale feature as congestion in the underlying network. The clustering coefficient concept is applied to three cases of indoor sensor networks, under varying thresholds on the link packet reception rate (PRR. A transition from positive curvature (“meshed” network to negative curvature (“core concentric” network is observed by increasing the threshold. Even though this paper deals with network curvature per se, we nevertheless expand on the underlying congestion motivation, propose several new concepts (network inertia and centroid, and finally we argue that greedy routing on a virtual positively curved network achieves load balancing on the physical network.
Discharge Coefficient of Rectangular Short-Crested Weir with Varying Slope Coefficients
Directory of Open Access Journals (Sweden)
Yuejun Chen
2018-02-01
Full Text Available Rectangular short-crested weirs are widely used for simple structure and high discharge capacity. As one of the most important and influential factors of discharge capacity, side slope can improve the hydraulic characteristics of weirs at special conditions. In order to systemically study the effects of upstream and downstream slope coefficients S1 and S2 on overflow discharge coefficient in a rectangular short-crested weir the Volume of Fluid (VOF method and the Renormalization Group (RNG κ-ε turbulence model are used. In this study, the slope coefficient ranges from V to 3H:1V and each model corresponds to five total energy heads of H0 ranging from 8.0 to 24.0 cm. Comparisons of discharge coefficients and free surface profiles between simulated and laboratory results display a good agreement. The simulated results show that the difference of discharge coefficients will decrease with upstream slopes and increase with downstream slopes as H0 increases. For a given H0, the discharge coefficient has a convex parabolic relation with S1 and a piecewise linearity relation with S2. The maximum discharge coefficient is always obtained at S2 = 0.8. There exists a difference between upstream and downstream slope coefficients in the influence range of free surface curvatures. Furthermore, a proposed discharge coefficient equation by nonlinear regression is a function of upstream and downstream slope coefficients.
Transfer of risk coefficients across populations
International Nuclear Information System (INIS)
Rasmussen, L.R.
1992-01-01
The variation of lifetime risk projections for a Canadian population caused by the uncertainty in the choice of method for transferring excess relative risk coefficients between populations is assessed. Site-specific projections, varied by factors up to 3.5 when excess risk coefficients of the BEIR V relative risk models were transferred to the Canadian population using an additive and multiplicative method. When the risk from all cancers are combined, differences between transfer methods were no longer significant. The Canadian projections were consistent with the ICRP-60 nominal fatal cancer risk estimates. (author)
Dependence of sputtering coefficient on ion dose
International Nuclear Information System (INIS)
Colligon, J.S.; Patel, M.H.
1977-01-01
The sputtering coefficient of polycrystalline gold bombarded by 10-40 keV Ar + ions had been measured as a function of total ion dose and shown to exhibit oscillations in magnitude between 30 and 100%. Possible experimental errors which would give rise to such an oscillation have been considered, but it is apparent that these factors are unable to explain the measurements. It is proposed that a change in the Sublimation Energy associated with either bulk damage or formation of surface topographical features arising during ion bombardment may be responsible for the observed variations in sputtering coefficient. (author)
A Simple Measure of Price Adjustment Coefficients.
Damodaran, Aswath
1993-01-01
One measure of market efficiency is the speed with which prices adjust to new information. The author develops a simple approach to estimating these price adjustment coefficients by using the information in return processes. This approach is used to estimate t he price adjustment coefficients for firms listed on the NYSE and the A MEX as well as for over-the-counter stocks. The author finds evidence of a lagged adjustment to new information in shorter return intervals for firms in all market ...
Modelling of power-reactivity coefficient measurement
International Nuclear Information System (INIS)
Strmensky, C.; Petenyi, V.; Jagrik, J.; Minarcin, M.; Hascik, R.; Toth, L.
2005-01-01
Report describes results of modeling of power-reactivity coefficient analysis on power-level. In paper we calculate values of discrepancies arisen during transient process. These discrepancies can be arisen as result of experiment evaluation and can be caused by disregard of 3D effects on neutron distribution. The results are critically discussed (Authors)
The Evolution of Pearson's Correlation Coefficient
Kader, Gary D.; Franklin, Christine A.
2008-01-01
This article describes an activity for developing the notion of association between two quantitative variables. By exploring a collection of scatter plots, the authors propose a nonstandard "intuitive" measure of association; and by examining properties of this measure, they develop the more standard measure, Pearson's Correlation Coefficient. The…
Regularity of the Interband Light Absorption Coefficient
Indian Academy of Sciences (India)
In this paper we consider the interband light absorption coefficient (ILAC), in a symmetric form, in the case of random operators on the -dimensional lattice. We show that the symmetrized version of ILAC is either continuous or has a component which has the same modulus of continuity as the density of states.
Automatic estimation of pressure-dependent rate coefficients.
Allen, Joshua W; Goldsmith, C Franklin; Green, William H
2012-01-21
A general framework is presented for accurately and efficiently estimating the phenomenological pressure-dependent rate coefficients for reaction networks of arbitrary size and complexity using only high-pressure-limit information. Two aspects of this framework are discussed in detail. First, two methods of estimating the density of states of the species in the network are presented, including a new method based on characteristic functional group frequencies. Second, three methods of simplifying the full master equation model of the network to a single set of phenomenological rates are discussed, including a new method based on the reservoir state and pseudo-steady state approximations. Both sets of methods are evaluated in the context of the chemically-activated reaction of acetyl with oxygen. All three simplifications of the master equation are usually accurate, but each fails in certain situations, which are discussed. The new methods usually provide good accuracy at a computational cost appropriate for automated reaction mechanism generation.
Absorption coefficients of silicon: A theoretical treatment
Tsai, Chin-Yi
2018-05-01
A theoretical model with explicit formulas for calculating the optical absorption and gain coefficients of silicon is presented. It incorporates direct and indirect interband transitions and considers the effects of occupied/unoccupied carrier states. The indirect interband transition is calculated from the second-order time-independent perturbation theory of quantum mechanics by incorporating all eight possible routes of absorption or emission of photons and phonons. Absorption coefficients of silicon are calculated from these formulas. The agreements and discrepancies among the calculated results, the Rajkanan-Singh-Shewchun (RSS) formula, and Green's data are investigated and discussed. For example, the RSS formula tends to overestimate the contributions of indirect transitions for cases with high photon energy. The results show that the state occupied/unoccupied effect is almost negligible for silicon absorption coefficients up to the onset of the optical gain condition where the energy separation of Quasi-Femi levels between electrons and holes is larger than the band-gap energy. The usefulness of using the physics-based formulas, rather than semi-empirical fitting ones, for absorption coefficients in theoretical studies of photovoltaic devices is also discussed.
The coefficient of friction, particularly of ice
International Nuclear Information System (INIS)
Mills, Allan
2008-01-01
The static and dynamic coefficients of friction are defined, and values from 0.3 to 0.6 are quoted for common materials. These drop to about 0.15 when oil is added as a lubricant. Water ice at temperatures not far below 0 °C is remarkable for low coefficients of around 0.05 for static friction and 0.04–0.02 for dynamic friction, but these figures increase as the temperature diminishes. Reasons for the slipperiness of ice are summarized, but they are still not entirely clear. One hypothesis suggests that it is related to the transient formation of a lubricating film of liquid water produced by frictional heating. If this is the case, some composition melting a little above ambient temperatures might provide a skating rink that did not require expensive refrigeration. Various compositions have been tested, but an entirely satisfactory material has yet to be found
Bayesian Meta-Analysis of Coefficient Alpha
Brannick, Michael T.; Zhang, Nanhua
2013-01-01
The current paper describes and illustrates a Bayesian approach to the meta-analysis of coefficient alpha. Alpha is the most commonly used estimate of the reliability or consistency (freedom from measurement error) for educational and psychological measures. The conventional approach to meta-analysis uses inverse variance weights to combine…
Probability based calibration of pressure coefficients
DEFF Research Database (Denmark)
Hansen, Svend Ole; Pedersen, Marie Louise; Sørensen, John Dalsgaard
2015-01-01
Normally, a consistent basis for calculating partial factors focuses on a homogeneous reliability index neither depending on which material the structure is constructed of nor the ratio between the permanent and variable actions acting on the structure. Furthermore, the reliability index should n...... the characteristic shape coefficients are based on mean values as specified in background documents to the Eurocodes. Importance of hidden safeties judging the reliability is discussed for wind actions on low-rise structures....... not depend on the type of variable action. A probability based calibration of pressure coefficients have been carried out using pressure measurements on the standard CAARC building modelled on scale of 1:383. The extreme pressures measured on the CAARC building model in the wind tunnel have been fitted.......3, the Eurocode partial factor of 1.5 for variable actions agrees well with the inherent uncertainties of wind actions when the pressure coefficients are determined using wind tunnel test results. The increased bias and uncertainty when pressure coefficients mainly are based on structural codes lead to a larger...
Computation of Clebsch-Gordan and Gaunt coefficients using binomial coefficients
International Nuclear Information System (INIS)
Guseinov, I.I.; Oezmen, A.; Atav, Ue
1995-01-01
Using binomial coefficients the Clebsch-Gordan and Gaunt coefficients were calculated for extremely large quantum numbers. The main advantage of this approach is directly calculating these coefficients, instead of using recursion relations. Accuracy of the results is quite high for quantum numbers l 1 , and l 2 up to 100. Despite direct calculation, the CPU times are found comparable with those given in the related literature. 11 refs., 1 fig., 2 tabs
Problems on Divisibility of Binomial Coefficients
Osler, Thomas J.; Smoak, James
2004-01-01
Twelve unusual problems involving divisibility of the binomial coefficients are represented in this article. The problems are listed in "The Problems" section. All twelve problems have short solutions which are listed in "The Solutions" section. These problems could be assigned to students in any course in which the binomial theorem and Pascal's…
Xing, X.; Yuan, Z.; Chen, L. F.; Yu, X. Y.; Xiao, L.
2018-04-01
The stability control is one of the major technical difficulties in the field of highway subgrade construction engineering. Building deformation model is a crucial step for InSAR time series deformation monitoring. Most of the InSAR deformation models for deformation monitoring are pure empirical mathematical models, without considering the physical mechanism of the monitored object. In this study, we take rheology into consideration, inducing rheological parameters into traditional InSAR deformation models. To assess the feasibility and accuracy for our new model, both simulation and real deformation data over Lungui highway (a typical highway built on soft clay subgrade in Guangdong province, China) are investigated with TerraSAR-X satellite imagery. In order to solve the unknows of the non-linear rheological model, three algorithms: Gauss-Newton (GN), Levenberg-Marquarat (LM), and Genetic Algorithm (GA), are utilized and compared to estimate the unknown parameters. Considering both the calculation efficiency and accuracy, GA is chosen as the final choice for the new model in our case study. Preliminary real data experiment is conducted with use of 17 TerraSAR-X Stripmap images (with a 3-m resolution). With the new deformation model and GA aforementioned, the unknown rheological parameters over all the high coherence points are obtained and the LOS deformation (the low-pass component) sequences are generated.
Analysis of flow coefficient in chair manufacture
Directory of Open Access Journals (Sweden)
Ivković Dragoljub
2005-01-01
Full Text Available The delivery on time is not possible without the good-quality planning of deadlines, i.e. planning of the manufacturing process duration. The study of flow coefficient enables the realistic forecasting of the manufacturing process duration. This paper points to the significance of the study of flow coefficient on scientific basis so as to determine the terms of the end of the manufacture of chairs made of sawn timber. Chairs are the products of complex construction, often almost completely made of sawn timber as the basic material. They belong to the group of export products, so it is especially significant to analyze the duration of the production cycle, and the type and the degree of stoppages in this type of production. Parallel method of production is applied in chair manufacture. The study shows that the value of flow coefficient is close to one or higher, in most cases. The results indicate that the percentage of interoperational stoppage is unjustifiably high, so it is proposed how to decrease the percentage of stoppages in the manufacturing process.
Activity coefficient of aqueous sodium bicarbonate
Energy Technology Data Exchange (ETDEWEB)
Pitzer, Kenneth S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Peiper, J. Christopher [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
1980-09-01
The determination of the activity coefficient and related properties of sodium bicarbonate presents special problems because of the appreciable vapor pressure of CO_{2} above such solutions. With the development of reliable equations for the thermodynamic properties of mixed electrolytes, it is possible to determine the parameters for NaHCO_{3} from cell measurements or NaCl-NaHCO_{3} mixtures. Literature data are analyzed to illustrate the method and provide interim values, hoever it is noted that further measurements over a wider range of concentrations would yield more definitive results. Lastly, an estimate is also given for the activity coefficient of KHCO_{3}.
Relations between coefficients of fractional parentage
International Nuclear Information System (INIS)
Zamick, L.
2007-01-01
For each of the (9/2) (11/2), and (13/2) single j shells we have only one state with J=j v=3 for a five particle system. For four identical particles there can be more than one state of seniority four. We note some 'ratio' relations for the coefficients of fractional parentage for the four and five identical particle systems, which are found in the works of de Shalit and Talmi [Nuclear Shell Theory (Academic Press, New York, 1963)] and Talmi [Simple Models of Complex Nuclei (Harwood Academic, Reading, UK, 1993)] to be useful for explaining the vanishing of a five particle coefficients of fractional parentage (cfp). These relations are used to show that there is a special (g 9/2 ) 4 I=4 v=4 wave function that cannot be admixed with an I=4 v=2 wave function, even with seniority violating interactions
DEFF Research Database (Denmark)
Jeong, Cheol-Ho; Chang, Ji-ho
2015-01-01
largely depending on the test room. Several conversion methods for porous absorbers from the Sabine absorption coefficient to the random incidence absorption coefficient were suggested by considering the finite size of a test specimen and non-uniformly incident energy onto the specimen, which turned out...... resistivity optimization outperforms the surface impedance optimization in terms of the reproducibility....
Heat transfer coefficients during quenching of steels
Energy Technology Data Exchange (ETDEWEB)
Hasan, H.S.; Jalil, J.M. [University of Technology, Department of Electromechanical Engineering, Baghdad (Iraq); Peet, M.J.; Bhadeshia, H.K.D.H. [University of Cambridge, Department of Materials Science and Metallurgy, Cambridge (United Kingdom)
2011-03-15
Heat transfer coefficients for quenching in water have been measured as a function of temperature using steel probes for a variety of iron alloys. The coefficients were derived from measured cooling curves combined with calculated heat-capacities. The resulting data were then used to calculate cooling curves using the finite volume method for a large steel sample and these curves have been demonstrated to be consistent with measured values for the large sample. Furthermore, by combining the estimated cooling curves with time-temperature-transformation (TTT) diagrams it has been possible to predict the variation of hardness as a function of distance via the quench factor analysis. The work should prove useful in the heat treatment of the steels studied, some of which are in the development stage. (orig.)
Activity coefficients of solutes in binary solvents
International Nuclear Information System (INIS)
Gokcen, N.A.
1982-01-01
The activity coefficients in dilute ternary systems are discussed in detail by using the Margules equations. Analyses of some relevant data at high temperatures show that the sparingly dissolved solutes in binary solvents follow complex behavior even when the binary solvents are very nearly ideal. It is shown that the activity data on the solute or the binary system cannot permit computation of the remaining activities except for the regular solutions. It is also shown that a fourth-order equation is usually adequate in expressing the activity coefficient of a solute in binary solvents at high temperatures. When the activity data for a binary solvent are difficult to obtain in a certain range of composition, the activity data for a sparingly dissolved solute can be used to supplement determination of the binary activities
Correlation and prediction of gaseous diffusion coefficients.
Marrero, T. R.; Mason, E. A.
1973-01-01
A new correlation method for binary gaseous diffusion coefficients from very low temperatures to 10,000 K is proposed based on an extended principle of corresponding states, and having greater range and accuracy than previous correlations. There are two correlation parameters that are related to other physical quantities and that are predictable in the absence of diffusion measurements. Quantum effects and composition dependence are included, but high-pressure effects are not. The results are directly applicable to multicomponent mixtures.
The solubility and diffusion coefficient of helium in uranium dioxide
International Nuclear Information System (INIS)
Nakajima, Kunihisa; Serizawa, Hiroyuki; Shirasu, Noriko; Haga, Yoshinori; Arai, Yasuo
2011-01-01
Highlights: ► The solubility and diffusivity of He in single-crystal UO 2 were determined. ► The determined He solubility lay within the scatter of the available data. ► The determined He diffusivity was in good agreement with recent experimental data. ► The He behavior was analyzed in terms of a simple interstitial diffusion mechanism. ► The experimental diffusivity was much lower than that analyzed theoretically. - Abstract: The solubility and diffusion coefficient of helium in the single-crystal UO 2 samples were determined by a Knudsen-effusion mass-spectrometric method. The measured helium solubilities were found to lie within the scatter of the available data, but to be much lower than those for the polycrystalline samples. The diffusion analysis was conducted based on a hypothetical equivalent sphere model and the simple Fick’s law. The helium diffusion coefficient was determined by using the pre-exponential factor and activation energy as the fitting parameters for the measured and calculated fractional releases of helium. The optimized diffusion coefficients were in good agreement with those obtained by a nuclear reaction method reported in the past. It was also found that the pre-exponential factors of the determined diffusion coefficients were much lower than those analyzed in terms of a simple interstitial diffusion mechanism.
Solubility and diffusion coefficient of oxygen in silicon
International Nuclear Information System (INIS)
Itoh, Yoshiko; Nozaki, Tadashi
1985-01-01
The solubility and diffusion coefficient of oxygen in silicon between 1000 0 C and 1375 0 C were examined by charged particle activation analysis with the 16 O( 3 He,p) 18 F reaction, in which oxygen was activated with an equal probability over the depth of up to 250μm by a specially devised apparatus. Silicon wafers of known histories were heated in oxygen or argon for 12 to 473 hours, and the resultant oxygen depth profiles were determined by the activation, subsequent stepwise etching and 18 F activity measurement. The solubility thus obtained is given as 9.3 x 10 21 exp[-27.6kcal mol -1 /RT] at.cm -3 ; the diffusion coefficient has been found to be approximated as 3.2 exp[-67.1kcal mol -1 /RT] cm 2 s -1 over 1150 0 C, under which the apparent activation energy seems to decrease with decrease of temperature. (author)
Zhang, Juping; Yang, Chan; Jin, Zhen; Li, Jia
2018-07-14
In this paper, the correlation coefficients between nodes in states are used as dynamic variables, and we construct SIR epidemic dynamic models with correlation coefficients by using the pair approximation method in static networks and dynamic networks, respectively. Considering the clustering coefficient of the network, we analytically investigate the existence and the local asymptotic stability of each equilibrium of these models and derive threshold values for the prevalence of diseases. Additionally, we obtain two equivalent epidemic thresholds in dynamic networks, which are compared with the results of the mean field equations. Copyright © 2018 Elsevier Ltd. All rights reserved.
Quenching of Einstein-coefficients by photons
International Nuclear Information System (INIS)
Aumayr, F.; Skinner, C.H.; Suckewer, S.; Princeton Univ., NJ; Lee, W.
1991-02-01
Experimental evidence is presented for the change of Einstein's A-coefficients for spontaneous transitions from the upper laser level of an argon ion laser discharge due to the presence of the high-intensity laser flux. To demonstrate that this quenching effect cannot be attributed to a reduction in self-absorption of the strong spontaneous emission line, absorption and line profile measurements have been performed. Computer modelling of the reduction of self absorption due to Rabi splitting also indicated that this effect is too small to explain the observed quenching of spontaneous line emissions. 13 refs., 11 figs
Quenching of Einstein-coefficients by photons
International Nuclear Information System (INIS)
Aumayr, F.; Lee, W.; Skinner, C.H.; Suckewer, S.
1991-03-01
Experimental evidence is presented for the change of Einstein's A- coefficients for spontaneous transitions from the upper laser level of argon ion laser discharge due to the presence of the high- intensity laser flux. To demonstrate that this quenching effect cannot be attributed to a reduction in self-absorption of the strong spontaneous emission line, absorption and line profile measurements have been performed. Computer modelling of the reduction of self absorption due to Rabi splitting also indicated that this effect is too small to explain the observed quenching of spontaneous line emissions. 13 refs., 11 figs
Determination of coefficient matrices for ARMA model
International Nuclear Information System (INIS)
Tran Dinh Tri.
1990-10-01
A new recursive algorithm for determining coefficient matrices of ARMA model from measured data is presented. The Yule-Walker equations for the case of ARMA model are derived from the ARMA innovation equation. The recursive algorithm is based on choosing appropriate form of the operator functions and suitable representation of the (n+1)-th order operator functions according to ones with the lower order. Two cases, when the order of the AR part is equal to one of the MA part, and the optimal case, were considered. (author) 5 refs
Coefficient of performance of Stirling refrigerators
E Mungan, Carl
2017-09-01
Stirling coolers transfer heat in or out of the working fluid during all four stages of their operation, and their coefficient of performance depends on whether the non-isothermal heat exchanges are performed reversibly or irreversibly. Both of these possibilities can in principle be arranged. Notably, if the working fluid is an ideal gas, the input of energy in the form of heat during one isochoric step is equal in magnitude to the output during the other isochoric step in the cycle. The theoretical performance of the fridge can then attain the reversible Carnot limit if a regenerator is used, which is a high heat capacity material through which the gas flows. Various Stirling refrigerator configurations are analysed in this article at a level of presentation suitable for an introductory undergraduate thermodynamics course.
Accurate Determination of Tunneling-Affected Rate Coefficients: Theory Assessing Experiment.
Zuo, Junxiang; Xie, Changjian; Guo, Hua; Xie, Daiqian
2017-07-20
The thermal rate coefficients of a prototypical bimolecular reaction are determined on an accurate ab initio potential energy surface (PES) using ring polymer molecular dynamics (RPMD). It is shown that quantum effects such as tunneling and zero-point energy (ZPE) are of critical importance for the HCl + OH reaction at low temperatures, while the heavier deuterium substitution renders tunneling less facile in the DCl + OH reaction. The calculated RPMD rate coefficients are in excellent agreement with experimental data for the HCl + OH reaction in the entire temperature range of 200-1000 K, confirming the accuracy of the PES. On the other hand, the RPMD rate coefficients for the DCl + OH reaction agree with some, but not all, experimental values. The self-consistency of the theoretical results thus allows a quality assessment of the experimental data.
Transport coefficients of a dissociating gas
International Nuclear Information System (INIS)
Lebed', I.V.
1987-01-01
The calculation of the transport coefficients of a dissociating gas involves fundamental difficulties which arise when the internal degrees of freedom of the molecules are taken strictly into account. In practical calculations extensive use is made of the approximation in the context of which the dependence of a diffusion velocity of the molecule on its internal state is totally neglected. In this case the expressions for the stress tensor and the diffusion velocities coincide with the corresponding expressions for a mixture of structureless particles; in the expression for the heat flux the diffusion transport of internal energy is taken only approximately into account. Here, analytic expressions for the diffusion velocities, heat flux and stress tensor are obtained without introducing simplifying assumptions. The calculation method is based on an approximate method of calculating the transport coefficients of a multicomponent mixture of structureless particles. The relations obtained are analyzed and compared with the existing results; their accuracy is estimated. A closed system of equations of gas dynamics is presented for a number of cases of practical importance
Sets of Fourier coefficients using numerical quadrature
International Nuclear Information System (INIS)
Lyness, J. N.
2001-01-01
One approach to the calculation of Fourier trigonometric coefficients f(r) of a given function f(x) is to apply the trapezoidal quadrature rule to the integral representation f(r)=(line i ntegral)(sub 0)(sup 1) f(x)e(sup -2(pi)irx)dx. Some of the difficulties in this approach are discussed. A possible way of overcoming many of these is by means of a subtraction function. Thus, one sets f(x)= h(sub p-1)(x)+ g(sub p)(x), where h(sub -1)(x) is an algebraic polynomial of degree p-1, specified in such a way that the Fourier series of g(sub p)(x) converges more rapidly than that of f(x). To obtain the Fourier coefficients of f(x), one uses an analytic expression for those of h(sub p-1)(x) and numerical quadrature to approximately those of g(sub p)(x)
Graphical comparison of calculated internal conversion coefficients
International Nuclear Information System (INIS)
Ewbank, W.B.
1980-11-01
Calculated values of the coefficients of internal conversion of gamma rays in the K shell and L 1 , L 2 , L 3 subshells from published tabulations by Band and Trzhaskovskaya and by Roesel et al. at Data Nucl. Data Tables, 21, 92-514(1978) are compared with values obtained by computer interpolation among tabulated values of Hager and Seltzer Nucl. Data, A4, 1-235(1968). In some cases, agreement among the three calculations is remarkably good, and differences are generally less than 5%. In a few cases, there are differences as large as 20 to 50%, corresponding to the threshold effect described by Roesel et al. The Z-dependent resonance minimum described by Roesel et al. is also observed in the comparison of E1-E4 conversion in the L 1 subshell. In several cases (notably M1-M4 conversion in the K shell and L 1 subshell), the Band and Roesel calculations show dramatically different dependence on gamma energy and atomic number. For Z = 100, the Band calculation for E4 conversion in the L 3 subshell shows irregular behavior at energies below the K-shell binding energy. A few high-quality measurements of internal conversion coefficients (+-5%) would help greatly to establish a basis for choice among the theoretical calculations. 32 figures
Comparison of field-measured radon diffusion coefficients with laboratory-measured coefficients
International Nuclear Information System (INIS)
Lepel, E.A.; Silker, W.B.; Thomas, V.W.; Kalkwarf, D.R.
1983-04-01
Experiments were conducted to compare radon diffusion coefficients determined for 0.1-m depths of soils by a steady-state method in the laboratory and diffusion coefficients evaluated from radon fluxes through several-fold greater depths of the same soils covering uranium-mill tailings. The coefficients referred to diffusion in the total pore volume of the soils and are equivalent to values for the quantity, D/P, in the Generic Environmental Impact Statement on Uranium Milling prepared by the US Nuclear Regulatory Commission. Two soils were tested: a well-graded sand and an inorganic clay of low plasticity. For the flux evaluations, radon was collected by adsorption on charcoal following passive diffusion from the soil surface and also from air recirculating through an aluminum tent over the soil surface. An analysis of variance in the flux evaluations showed no significant difference between these two collection methods. Radon diffusion coefficients evaluated from field data were statistically indistinguishable, at the 95% confidence level, from those measured in the laboratory; however, the low precision of the field data prevented a sensitive validation of the laboratory measurements. From the field data, the coefficients were calculated to be 0.03 +- 0.03 cm 2 /s for the sand cover and 0.0036 +- 0.0004 cm 2 /s for the clay cover. The low precision in the coefficients evaluated from field data was attributed to high variation in radon flux with time and surface location at the field site
Forecast Correlation Coefficient Matrix of Stock Returns in Portfolio Analysis
Zhao, Feng
2013-01-01
In Modern Portfolio Theory, the correlation coefficients decide the risk of a set of stocks in the portfolio. So, to understand the correlation coefficients between returns of stocks, is a challenge but is very important for the portfolio management. Usually, the stocks with small correlation coefficients or even negative correlation coefficients are preferred. One can calculate the correlation coefficients of stock returns based on the historical stock data. However, in order to control the ...
Energy Technology Data Exchange (ETDEWEB)
McCleskey, M; Mukhamedzhanov, A M; Trache, L; Tribble, R E; Banu, A; Eremenko, V; Goldberg, V Z; Lui, Y W; McCleskey, E; Roeder, B T; Spiridon, A; Carstoiu, F; Burjan, V; Hons, Z; Thompson, I J
2014-04-17
The ^{14}C + n <--> ^{15}C system has been used as a test case in the evaluation of a new method to determine spectroscopic factors that uses the asymptotic normalization coefficient (ANC). The method proved to be unsuccessful for this case. As part of this experimental program, the ANCs for the ^{15}C ground state and first excited state were determined using a heavy-ion neutron transfer reaction as well as the inverse kinematics (d,p) reaction, measured at the Texas A&M Cyclotron Institute. The ANCs were used to evaluate the astrophysical direct neutron capture rate on ^{14}C, which was then compared with the most recent direct measurement and found to be in good agreement. A study of the ^{15}C SF via its mirror nucleus ^{15}F and a new insight into deuteron stripping theory are also presented.
Kinetic studies of elementary chemical reactions
Energy Technology Data Exchange (ETDEWEB)
Durant, J.L. Jr. [Sandia National Laboratories, Livermore, CA (United States)
1993-12-01
This program concerning kinetic studies of elementary chemical reactions is presently focussed on understanding reactions of NH{sub x} species. To reach this goal, the author is pursuing experimental studies of reaction rate coefficients and product branching fractions as well as using electronic structure calculations to calculate transition state properties and reaction rate calculations to relate these properties to predicted kinetic behavior. The synergy existing between the experimental and theoretical studies allow one to gain a deeper insight into more complex elementary reactions.
International Nuclear Information System (INIS)
Mukhamedzhanov, A. M.; Gagliardi, C. A.; Goldberg, V. Z.; Plunkett, A.; Trache, L.; Tribble, R. E.; Bem, P.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Novak, J.; Piskor, S.; Simeckova, E.; Vesely, F.; Vincour, J.; La Cognata, M.; Pizzone, R. G.; Romano, S.; Spitaleri, C.
2008-01-01
The 15 N(p,γ) 16 O reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong J π =1 - resonances at E R =312 and 962 keV and direct capture to the ground state. Asymptotic normalization coefficients (ANCs) for the ground and seven excited states in 16 O were extracted from the comparison of experimental differential cross sections for the 15 N( 3 He,d) 16 O reaction with distorted-wave Born approximation calculations. Using these ANCs and proton and α resonance widths determined from an R-matrix fit to the data from the 15 N(p,α) 12 C reaction, we carried out an R-matrix calculation to obtain the astrophysical factor for the 15 N(p,γ) 16 O reaction. The results indicate that the direct capture contribution was previously overestimated. We find the astrophysical factor to be S(0)=36.0±6.0 keV b, which is about a factor of 2 lower than the presently accepted value. We conclude that for every 2200±300 cycles of the main CN cycle one CN catalyst is lost due to this reaction
Prediction of friction coefficients for gases
Taylor, M. F.
1969-01-01
Empirical relations are used for correlating laminar and turbulent friction coefficients for gases, with large variations in the physical properties, flowing through smooth tubes. These relations have been used to correlate friction coefficients for hydrogen, helium, nitrogen, carbon dioxide and air.
Thermal linear expansion coefficient of structural graphites
International Nuclear Information System (INIS)
Virgil'ev, Yu.S.
1995-01-01
The data now available on radiation induced changes of linear thermal expansion coefficients (CTE) for native structural carbon materials (SCM) irradiated with high fluences are summarized. For different types of native and foreign SCM dose dependences of CTE changes in the temperature range of 300...1600 K and at fluences up to (2...3)x10 22 n/cm 2 (E>0.18 meV) are compared. On the base of this comparison factors defined the CTE changes under neutron irradiation are revealed and the explanation of observed phenomena is offered. Large number of the factors revealed does not allowed to calculate CTE radiation induced changes. 39 refs.; 16 figs.; 5 tabs
Nuclear data for the calculation of thermal reactor reactivity coefficients
International Nuclear Information System (INIS)
1989-01-01
On its 15th meeting in Vienna, 16-20 June 1986, the International Nuclear Data Committee (INDC) considered it important to review the accuracy with which changes in thermal reactor reactivity resulting from changes in temperature and coolant density can be predicted. It was noted that reactor physicists in several countries had to adjust the thermal neutron cross-section data base in order to reproduce measured reactivity coefficients. Consequently, it appeared to be essential to examine the consistency of the integral and differential cross-section data and to make all the information available which has a bearing on reactivity coefficient prediction. Following the recommendation of the INDC, the Nuclear Data Section of the International Atomic Energy Agency, therefore, convened the Advisory Group Meeting on Nuclear Data for the Calculation of Thermal Reaction Reactivity Coefficients, in Vienna, Austria, 7-10 Dec. 1987. The Conclusions and Recommendations of the meeting together with the papers presented, are submitted in the present document. A separate abstract was prepared for each of these 12 papers. Refs, figs and tabs
An Investigation of the Sampling Distribution of the Congruence Coefficient.
Broadbooks, Wendy J.; Elmore, Patricia B.
This study developed and investigated an empirical sampling distribution of the congruence coefficient. The effects of sample size, number of variables, and population value of the congruence coefficient on the sampling distribution of the congruence coefficient were examined. Sample data were generated on the basis of the common factor model and…
Coefficient of Friction of Human Corneal Tissue.
Wilson, Tawnya; Aeschlimann, Rudolf; Tosatti, Samuele; Toubouti, Youssef; Kakkassery, Joseph; Osborn Lorenz, Katherine
2015-09-01
A novel property evaluation methodology was used to determine the elusive value for the human corneal coefficient of friction (CoF). Using a microtribometer on 28 fresh human donor corneas with intact epithelia, the CoF was determined in 4 test solutions (≥5 corneas/solution): tear-mimicking solution (TMS) in borate-buffered saline (TMS-PS), TMS in phosphate-buffered saline (TMS-PBS), TMS with HEPES-buffered saline (TMS-HEPES), and tear-like fluid in PBS (TLF-PBS). Mean (SD) CoF values ranged from 0.006 to 0.015 and were 0.013 (0.010) in TMS-PS, 0.006 (0.003) in TMS-PBS, 0.014 (0.005) in TMS-HEPES, and 0.015 (0.009) in TLF-PBS. Statistically significant differences were shown for TMS-PBS versus TLF (P = 0.0424) and TMS-PBS versus TMS-HEPES (P = 0.0179), but not for TMS-PBS versus TMS-PS (P = 0.2389). Successful measurement of the fresh human corneal tissue CoF was demonstrated, with values differing in the evaluated buffer solutions, within this limited sample size.
Expansive soil stabilization with coir waste and lime for flexible pavement subgrade
Narendra Goud, G.; Hyma, A.; Shiva Chandra, V.; Sandhya Rani, R.
2018-03-01
Expansive soil properties can be improved by various methods to make it suitable for construction of flexible pavement. The coir pith is the by-product (bio-waste) generated from coir industry during extraction of coir fiber from coconut husk. Openly disposed coir pith can make the surrounding areas unhygienic. This bio-waste can be one of the potential materials to stabilize the expansive soils. In the present study coir pith and lime are used as stabilizers. Different combinations of coir pith contents (1%, 2% and 3%) and lime contents (2%, 3% and 4%)are used to study the behavior of expansive soil. Unconfined compressive strength (UCS) of unstabilized and stabilized soils was determined. Optimum content of coir pith and lime are determined based on UCS of the soil. California bearing ratio of soil determined at optimum contents of coir pith and lime. Flexible pavement layer compositions for two levels of traffic using stabilized soil subgrade.
Molar extinction coefficients of some fatty acids
DEFF Research Database (Denmark)
Sandhu, G.K.; Singh, K.; Lark, B.S.
2002-01-01
) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement......The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2...
Resilient modulus for unbound granular materials and subgrade soils in Egypt
Directory of Open Access Journals (Sweden)
Mousa Rabah
2017-01-01
Full Text Available Mechanistic Empirical (ME pavement design methods started to gain attention especially the last couple of years in Egypt and the Middle East. One of the challenges facing the spread of these methods in Egypt is lack of advanced properties of local soil and asphalt, which are needed as input data in ME design. Resilient modulus (Mr for example is an important engineering property that expresses the elastic behavior of soil/unbound granular materials (UGMs under cyclic traffic loading for ME design. In order to overcome the scarcity of the resilient modulus data for soil/UGMs in Egypt, a comprehensive laboratory testing program was conducted to measure resilient modulus of typical UGMs and subgrade soils typically used in pavement construction in Egypt. The factors that affect the resilient modulus of soil/UGMs were reviewed, studied and discussed. Finally, the prediction accuracy of the most well-known Mr Prediction models for the locally investigated materials was investigated.
Rate Coefficient for the (4)Heμ + CH4 Reaction at 500 K: Comparison between Theory and Experiment.
Arseneau, Donald J; Fleming, Donald G; Li, Yongle; Li, Jun; Suleimanov, Yury V; Guo, Hua
2016-03-03
The rate constant for the H atom abstraction reaction from methane by the muonic helium atom, Heμ + CH4 → HeμH + CH3, is reported at 500 K and compared with theory, providing an important test of both the potential energy surface (PES) and reaction rate theory for the prototypical polyatomic CH5 reaction system. The theory used to characterize this reaction includes both variational transition-state (CVT/μOMT) theory (VTST) and ring polymer molecular dynamics (RPMD) calculations on a recently developed PES, which are compared as well with earlier calculations on different PESs for the H, D, and Mu + CH4 reactions, the latter, in particular, providing for a variation in atomic mass by a factor of 36. Though rigorous quantum calculations have been carried out for the H + CH4 reaction, these have not yet been extended to the isotopologues of this reaction (in contrast to H3), so it is important to provide tests of less rigorous theories in comparison with kinetic isotope effects measured by experiment. In this regard, the agreement between the VTST and RPMD calculations and experiment for the rate constant of the Heμ + CH4 reaction at 500 K is excellent, within 10% in both cases, which overlaps with experimental error.
2009-10-01
This report documents the results of a study that was conducted to characterize the behavior of geogrid reinforced base : course materials. The research was conducted through an experimental testing and numerical modeling programs. The : experimental...
Instrumentation and analysis of frost heave mitigation on WY-70, Encampment, WY.
2014-05-01
This project investigated a novel procedure to reduce or prevent subgrade freezing non-destructively by injecting a two-part polymer foam at : the top of the subgrade. Controlled injection of Uretek Star, expanding structural polymer foam, created a ...
International Nuclear Information System (INIS)
Pin, F.G.; Witten, A.J.; Sharp, R.D.; Long, E.C. Jr.
1983-08-01
A computer code (MIGRAT) is developed to quantify the migration of moisture and multiple decaying and retarded contaminants in the unsaturated zone. MIGRAT was specifically conceived to assess the impacts of open mine to allow its use in many problems related to shallow, subsurface waste disposal. The model is applied to a generic uranium-mill-tailings pit constructed with a clay-lined bottom and steep unlined sidewalls. The contaminant decays and only one contaminant is retarded. This study shows the anticipated result that moisture and contamination migrate slowly through the bottom clay liner and that, in this migration, concentrations of the retarded contaminant significantly lag the unretarded contaminant. More importantly, this study reveals that the major pathway from the pit to the groundwater is through the sidewall. The time scales for this pathway are much shorter than those associated with the clay liner, and retardation has little effect on the rate of contaminant migration
Pawlak, Mariusz; Ben-Asher, Anael; Moiseyev, Nimrod
2018-01-09
We present a simple expression and its derivation for reaction rate coefficients for cold anisotropic collision experiments based on adiabatic variational theory and time-independent non-Hermitian scattering theory. We demonstrate that only the eigenenergies of the resulting one-dimensional Schrödinger equation for different complex adiabats are required. The expression is applied to calculate the Penning ionization rate coefficients of an excited metastable helium atom with molecular hydrogen in an energy range spanning from hundreds of kelvins down to the millikelvin regime. Except for trivial quantities like the masses of the nuclei and the bond length of the diatomic molecule participating in the collision, one needs as input data only the complex potential energy surface (CPES). In calculations, we used recently obtained ab initio CPES by D. Bhattacharya et al. ( J. Chem. Theory Comput. 2017 , 13 , 1682 - 1690 ) without fitting parameters. The results show good accord with current measurements ( Nat. Phys. 2017 , 13 , 35 - 38 ).
Automatic estimation of pressure-dependent rate coefficients
Allen, Joshua W.; Goldsmith, C. Franklin; Green, William H.
2012-01-01
A general framework is presented for accurately and efficiently estimating the phenomenological pressure-dependent rate coefficients for reaction networks of arbitrary size and complexity using only high-pressure-limit information. Two aspects of this framework are discussed in detail. First, two methods of estimating the density of states of the species in the network are presented, including a new method based on characteristic functional group frequencies. Second, three methods of simplifying the full master equation model of the network to a single set of phenomenological rates are discussed, including a new method based on the reservoir state and pseudo-steady state approximations. Both sets of methods are evaluated in the context of the chemically-activated reaction of acetyl with oxygen. All three simplifications of the master equation are usually accurate, but each fails in certain situations, which are discussed. The new methods usually provide good accuracy at a computational cost appropriate for automated reaction mechanism generation. This journal is © the Owner Societies.
Axially symmetric reconstruction of plasma emission and absorption coefficients
International Nuclear Information System (INIS)
Yang Lixin; Jia Hui; Yang Jiankun; Li Xiujian; Chen Shaorong; Liu Xishun
2013-01-01
A layered structure imaging model is developed in order to reconstruct emission coefficients and absorption coefficients simultaneously, in laser fusion core plasma diagnostics. A novel axially symmetric reconstruction method that utilizes the LM (Levenberg-Marquardt) nonlinear least squares minimization algorithm is proposed based on the layered structure. Numerical simulation results demonstrate that the proposed method is sufficiently accurate to reconstruct emission coefficients and absorption coefficients, and when the standard deviation of noise is 0.01, the errors of emission coefficients and absorption coefficients are 0.17, 0.22, respectively. Furthermore, this method could perform much better on reconstruction effect compared with traditional inverse Abel transform algorithms. (authors)
Thermodynamically based constraints for rate coefficients of large biochemical networks.
Vlad, Marcel O; Ross, John
2009-01-01
Wegscheider cyclicity conditions are relationships among the rate coefficients of a complex reaction network, which ensure the compatibility of kinetic equations with the conditions for thermodynamic equilibrium. The detailed balance at equilibrium, that is the equilibration of forward and backward rates for each elementary reaction, leads to compatibility between the conditions of kinetic and thermodynamic equilibrium. Therefore, Wegscheider cyclicity conditions can be derived by eliminating the equilibrium concentrations from the conditions of detailed balance. We develop matrix algebra tools needed to carry out this elimination, reexamine an old derivation of the general form of Wegscheider cyclicity condition, and develop new derivations which lead to more compact and easier-to-use formulas. We derive scaling laws for the nonequilibrium rates of a complex reaction network, which include Wegscheider conditions as a particular case. The scaling laws for the rates are used for clarifying the kinetic and thermodynamic meaning of Wegscheider cyclicity conditions. Finally, we discuss different ways of using Wegscheider cyclicity conditions for kinetic computations in systems biology.
Duong, Minh V; Nguyen, Hieu T; Mai, Tam V-T; Huynh, Lam K
2018-01-03
Master equation/Rice-Ramsperger-Kassel-Marcus (ME/RRKM) has shown to be a powerful framework for modeling kinetic and dynamic behaviors of a complex gas-phase chemical system on a complicated multiple-species and multiple-channel potential energy surface (PES) for a wide range of temperatures and pressures. Derived from the ME time-resolved species profiles, the macroscopic or phenomenological rate coefficients are essential for many reaction engineering applications including those in combustion and atmospheric chemistry. Therefore, in this study, a least-squares-based approach named Global Minimum Profile Error (GMPE) was proposed and implemented in the MultiSpecies-MultiChannel (MSMC) code (Int. J. Chem. Kinet., 2015, 47, 564) to extract macroscopic rate coefficients for such a complicated system. The capability and limitations of the new approach were discussed in several well-defined test cases.
2012-03-01
The inadequacy of many existing roads due to rapid growth in traffic volume provides a motivation for exploring alternatives to : existing methods of constructing and rehabilitating roads. The use of geosynthetics to stabilize and reinforce paved and...
Townsend coefficients of gases in avalanche counters
International Nuclear Information System (INIS)
Brunner, G.
1978-01-01
Though much work has been done by many authors in the last few years in the development and application of avalanche counters for ion radiation, it is based upon values of the Townsend coefficients as the essential gas parameter, which were determined many years ago for much lower reduced field strengths F/p than prevail in such counters. Therefore absolute determinations of α in vapours of methyl alcohol, cyclohexane, acetone, and n-heptene were performed under original conditions of avalanche counters. The values obtained do not differ by more than 30%-50% from the former values indeed, extrapolated over F/p for the first three mentioned substances, but the amounts of A and B in the usual representation α/p=A exp(-B(F/p)) are much greater for the stronger reduced fields. This is of importance for such counter properties as the dependence of pulse heights on pressure, voltage, electrode distance etc., which are governed by other combinations of A and B than α/p itself. A comparison of results for different ionic radiations shows a marked influence of the primary ionization density along the particle tracks which is hard to explain. (Auth.)
2008-01-01
The Midwest States Accelerated Pavement Testing Pooled Fund Program, financed by the highway departments : of Missouri, Iowa, Kansas and Nebraska, has supported an accelerated pavement testing (APT) project to compare : the performance of stabilized ...
The Attenuation of Correlation Coefficients: A Statistical Literacy Issue
Trafimow, David
2016-01-01
Much of the science reported in the media depends on correlation coefficients. But the size of correlation coefficients depends, in part, on the reliability with which the correlated variables are measured. Understanding this is a statistical literacy issue.
Asymmetrical slip propensity: required coefficient of friction.
Seo, Jung-suk; Kim, Sukwon
2013-07-31
Most studies in performing slips and falls research reported their results after the ipsilateral leg of subjects (either right foot or left foot) was guided to contact the contaminated floor surface although many studies indicated concerns for asymmetries of legs in kinematic or kinetic variables. Thus, the present study evaluated if dominant leg's slip tendency would be different from non-dominant leg's slip tendency by comparing the Required Coefficient of Friction (RCOF) of the two lower limbs. Forty seven health adults participated in the present study. RCOF was measured when left or right foot of subjects contacted the force platforms respectively. Paired t-test was performed to test if RCOF and heel velocity (HCV) of dominant legs was different from that of non-dominant legs. It was suggested that the asymmetry in RCOFs and HCV between the two lower limbs existed. The RCOFs of non-dominant legs were higher than that of dominant legs. The results indicated that asymmetry in slip propensity, RCOF, was existed in lower extremity. The results from the study suggested that it would be benefit to include a variable, such as asymmetry, in slips and falls research.
Effect of chemical reaction on unsteady MHD free convective two ...
African Journals Online (AJOL)
The effect of flow parameters on the coefficient of skin friction, Nusselt number and Sherwood number are also tabulated and discussed appropriately. It was observed that the increase in chemical reaction coefficient/parameter suppresses both velocity and concentration profiles. Keywords: Chemical Reaction, MHD, ...
Assessment of satellite derived diffuse attenuation coefficients ...
Optical data collected in coastal waters off South Florida and in the Caribbean Sea between January 2009 and December 2010 were used to evaluate products derived with three bio-optical inversion algorithms applied to MOIDS/Aqua, MODIS/Terra, and SeaWiFS satellite observations. The products included the diffuse attenuation coefficient at 490 nm (Kd_490) and for the visible range (Kd_PAR), and euphotic depth (Zeu, corresponding to 1% of the surface incident photosynthetically available radiation or PAR). Above-water hyperspectral reflectance data collected over optically shallow waters of the Florida Keys between June 1997 and August 2011 were used to help understand algorithm performance over optically shallow waters. The in situ data covered a variety of water types in South Florida and the Caribbean Sea, ranging from deep clear waters, turbid coastal waters, and optically shallow waters (Kd_490 range of ~0.03 – 1.29m-1). An algorithm based on Inherent Optical Properties (IOPs) showed the best performance (RMSD turbidity or shallow bottom contamination. Similar results were obtained when only in situ data were used to evaluate algorithm performance. The excellent agreement between satellite-derived remote sensing reflectance (Rrs) and in situ Rrs suggested that
On the Occurrence of Standardized Regression Coefficients Greater than One.
Deegan, John, Jr.
1978-01-01
It is demonstrated here that standardized regression coefficients greater than one can legitimately occur. Furthermore, the relationship between the occurrence of such coefficients and the extent of multicollinearity present among the set of predictor variables in an equation is examined. Comments on the interpretation of these coefficients are…
Determination of beta attenuation coefficients by means of timing method
International Nuclear Information System (INIS)
Ermis, E.E.; Celiktas, C.
2012-01-01
Highlights: ► Beta attenuation coefficients of absorber materials were found in this study. ► For this process, a new method (timing method) was suggested. ► The obtained beta attenuation coefficients were compatible with the results from the traditional one. ► The timing method can be used to determine beta attenuation coefficient. - Abstract: Using a counting system with plastic scintillation detector, beta linear and mass attenuation coefficients were determined for bakelite, Al, Fe and plexiglass absorbers by means of timing method. To show the accuracy and reliability of the obtained results through this method, the coefficients were also found via conventional energy method. Obtained beta attenuation coefficients from both methods were compared with each other and the literature values. Beta attenuation coefficients obtained through timing method were found to be compatible with the values obtained from conventional energy method and the literature.
Noncanonical Reactions of Flavoenzymes
Directory of Open Access Journals (Sweden)
Pablo Sobrado
2012-11-01
Full Text Available Enzymes containing flavin cofactors are predominantly involved in redox reactions in numerous cellular processes where the protein environment modulates the chemical reactivity of the flavin to either transfer one or two electrons. Some flavoenzymes catalyze reactions with no net redox change. In these reactions, the protein environment modulates the reactivity of the flavin to perform novel chemistries. Recent mechanistic and structural data supporting novel flavin functionalities in reactions catalyzed by chorismate synthase, type II isopentenyl diphosphate isomerase, UDP-galactopyranose mutase, and alkyl-dihydroxyacetonephosphate synthase are presented in this review. In these enzymes, the flavin plays either a direct role in acid/base reactions or as a nucleophile or electrophile. In addition, the flavin cofactor is proposed to function as a “molecular scaffold” in the formation of UDP-galactofuranose and alkyl-dihydroxyacetonephosphate by forming a covalent adduct with reaction intermediates.
Scheibler, Robin; Hurley, Paul
2012-03-01
We present a novel, accurate and fast algorithm to obtain Fourier series coefficients from an IC layer whose description consists of rectilinear polygons on a plane, and how to implement it using off-the-shelf hardware components. Based on properties of Fourier calculus, we derive a relationship between the Discrete Fourier Transforms of the sampled mask transmission function and its continuous Fourier series coefficients. The relationship leads to a straightforward algorithm for computing the continuous Fourier series coefficients where one samples the mask transmission function, compute its discrete Fourier transform and applies a frequency-dependent multiplicative factor. The algorithm is guaranteed to yield the exact continuous Fourier series coefficients for any sampling representing the mask function exactly. Computationally, this leads to significant saving by allowing to choose the maximal such pixel size and reducing the fast Fourier transform size by as much, without compromising accuracy. In addition, the continuous Fourier series is free from aliasing and follows closely the physical model of Fourier optics. We show that in some cases this can make a significant difference, especially in modern very low pitch technology nodes.
Transport coefficients of strongly interacting matter
International Nuclear Information System (INIS)
Heckmann, Klaus
2011-01-01
In this thesis, we investigate the dissipative transport phenomena of strongly interacting matter. The special interest is in the shear viscosity and its value divided by entropy density. The performed calculations are based on effective models for Quantum Chromodynamics, mostly focused on the 2-flavor Nambu-Jona-Lasinio model. This allows us to study the hadronic sector as well as the quark sector within one single model. We expand the models up to next-to-leading order in inverse numbers of colors. We present different possibilities of calculating linear transport coefficients and give an overview over qualitative properties as well as over recent ideas concerning ideal fluids. As present methods are not able to calculate the quark two-point function in Minkowski space-time in the self-consistent approximation scheme of the Nambu-Jona-Lasinio model, a new method for this purpose is developed. This self-energy parametrization method is applied to the expansion scheme, yielding the quark spectral function with meson back-coupling effects. The usage of this spectral function in the transport calculation is only one result of this work. We also test the application of different transport approaches in the NJL model, and find an interesting behavior of the shear viscosity at the critical end point of the phase diagram. We also use the NJL model to calculate the viscosity of a pion gas in the dilute regime. After an analysis of other models for pions and their interaction, we find that the NJL-result leads to an important modification of transport properties in comparison with the calculations which purely rely on pion properties in the vacuum. (orig.)
Coefficient of restitution of model repaired car body parts
D. Hadryś; M. Miros
2008-01-01
Purpose: The qualification of influence of model repaired car body parts on the value of coefficient of restitution and evaluation of impact energy absorption of model repaired car body parts.Design/methodology/approach: Investigation of plastic strain and coefficient of restitution of new and repaired model car body parts with using impact test machine for different impact energy.Findings: The results of investigations show that the value of coefficient of restitution changes with speed (ene...
A review of reaction rates in high temperature air
Park, Chul
1989-01-01
The existing experimental data on the rate coefficients for the chemical reactions in nonequilibrium high temperature air are reviewed and collated, and a selected set of such values is recommended for use in hypersonic flow calculations. For the reactions of neutral species, the recommended values are chosen from the experimental data that existed mostly prior to 1970, and are slightly different from those used previously. For the reactions involving ions, the recommended rate coefficients are newly chosen from the experimental data obtained more recently. The reacting environment is assumed to lack thermal equilibrium, and the rate coefficients are expressed as a function of the controlling temperature, incorporating the recent multitemperature reaction concept.
Radionuclides distribution coefficient of soil to soil-solution
International Nuclear Information System (INIS)
1990-06-01
The present book addresses various issues related with the coefficient of radionuclides distribution between soil and soil solution. It consists of six sections and two appendices. The second section, following an introductory one, describes the definition of the coefficient and a procedures of its calculation. The third section deals with the application of the distribution coefficient to the prediction of movements of radionuclides through soil. Various methods for measuring the coefficient are described in the fourth section. The next section discusses a variety of factors (physical and chemical) that can affect the distribution coefficient. Measurements of the coefficient for different types of oils are listed in the sixth section. An appendix is attached to the book to show various models that can be helpful in applying the coefficient of distribution of radionuclides moving from soil into agricultural plants. (N.K.)
Compilation report of VHTRC temperature coefficient benchmark calculations
Energy Technology Data Exchange (ETDEWEB)
Yasuda, Hideshi; Yamane, Tsuyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1995-11-01
A calculational benchmark problem has been proposed by JAERI to an IAEA Coordinated Research Program, `Verification of Safety Related Neutronic Calculation for Low-enriched Gas-cooled Reactors` to investigate the accuracy of calculation results obtained by using codes of the participating countries. This benchmark is made on the basis of assembly heating experiments at a pin-in block type critical assembly, VHTRC. Requested calculation items are the cell parameters, effective multiplication factor, temperature coefficient of reactivity, reaction rates, fission rate distribution, etc. Seven institutions from five countries have joined the benchmark works. Calculation results are summarized in this report with some remarks by the authors. Each institute analyzed the problem by applying the calculation code system which was prepared for the HTGR development of individual country. The values of the most important parameter, k{sub eff}, by all institutes showed good agreement with each other and with the experimental ones within 1%. The temperature coefficient agreed within 13%. The values of several cell parameters calculated by several institutes did not agree with the other`s ones. It will be necessary to check the calculation conditions again for getting better agreement. (J.P.N.).
Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation
Directory of Open Access Journals (Sweden)
Osamu Kuwano
2012-01-01
Full Text Available Electrokinetic phenomena are believed to be the most likely origin of electromagnetic signals preceding or accompanying earthquakes. The intensity of the source current due to the electrokinetic phenomena is determined by the fluid flux and the electrokinetic coupling coefficient called streaming current coefficient; therefore, how the coefficient changes before rupture is essential. Here, we show how the electrokinetic coefficients change during the rock deformation experiment up to failure. The streaming current coefficient did not increase before failure, but continued to decrease up to failure, which is explained in terms of the elastic closure of capillary. On the other hand, the streaming potential coefficient, which is the product of the streaming current coefficient and bulk resistivity of the rock, increased at the onset of dilatancy. It may be due to change in bulk resistivity. Our result indicates that the zeta potential of the newly created surface does not change so much from that of the preexisting fluid rock interface.
An experimental approach of decoupling Seebeck coefficient and electrical resistivity
Muhammed Sabeer N., A.; Paulson, Anju; Pradyumnan, P. P.
2018-04-01
The Thermoelectrics (TE) has drawn increased attention among renewable energy technologies. The performance of a thermoelectric material is quantified by a dimensionless thermoelectric figure of merit, ZT=S2σT/κ, where S and σ vary inversely each other. Thus, improvement in ZT is not an easy task. So, researchers have been trying different parameter variations during thin film processing to improve TE properties. In this work, tin nitride (Sn3N4) thin films were deposited on glass substrates by reactive RF magnetron sputtering and investigated its thermoelectric response. To decouple the covariance nature of Seebeck coefficient and electrical resistivity for the enhancement of power factor (S2σ), the nitrogen gas pressure during sputtering was reduced. Reduction in nitrogen gas pressure reduced both sputtering pressure and amount of nitrogen available for reaction during sputtering. This experimental approach of combined effect introduced preferred orientation and stoichiometric variations simultaneously in the sputtered Sn3N4 thin films. The scattering mechanism associated with these variations enhanced TE properties by independently drive the Seebeck coefficient and electrical resistivity parameters.
Static pressure and temperature coefficients of working standard microphones
DEFF Research Database (Denmark)
Barrera Figueroa, Salvador; Cutanda Henriquez, Vicente; Torras Rosell, Antoni
2016-01-01
be a significant contribution to the uncertainty of the measurement. Determining the environmental coefficients of individual specimens of measurement microphones can be a straightforward though time-consuming procedure provided the appropriate facilities are available. An alternative is to determine them using...... coefficients. For this purpose, the environmental coefficients of some commercially available microphones have been determined experimentally, and whenever possible, compared with the coefficients determined numerically using the Boundary Element Method....... for these coefficients which are used for calibration purposes. Working standard microphones are not exempt of these influences. However, manufacturers usually provide a low frequency value of the environmental coefficient. While in some applications the influence of this coefficient may be negligible, in others it may...
Reaction kinetics of polybutylene terephthalate polycondensation reaction
Darda, P. J.; Hogendoorn, J. A.; Versteeg, G. F.; Souren, F.
2005-01-01
The kinetics of the forward polycondensation reaction of polybutylene terephthalate (PBT) has been investigated using thermogravimetric analysis (TGA). PBT - prepolymer with an initial degree of polymerization of 5.5 was used as starting material. The PBT prepolymer was prepared from dimethyl
Cunningham, Kevin
2007-01-01
This article presents an assignment in which students are to research and report on a chemical reaction whose increased or decreased rate is of practical importance. Specifically, students are asked to represent the reaction they have chosen with an acceptable chemical equation, identify a factor that influences its rate and explain how and why it…
Classification of coefficients of variation in experiments with commercial layers
Directory of Open Access Journals (Sweden)
DE Faria Filho
2010-12-01
Full Text Available This study aimed at determining a specific classification of coefficients of variation in experiments with commercial layers. Coefficients of variation were collected from papers published in Brazilian journals between 2000 and 2009 for performance, internal egg quality, and eggshell quality parameters. The coefficients of variation of each parameter were classified as low, intermediate, high, and very high according to the ratio between the median and the pseudo-sigma. It was concluded that the parameters used in experiments with commercial layers have a specific classification of coefficients of variation, and that this must be considered to evaluate experimental accuracy.
Calculation of transport coefficients in an axisymmetric plasma
International Nuclear Information System (INIS)
Shumaker, D.E.
1976-01-01
A method of calculating the transport coefficient in an axisymmetric toroidal plasma is presented. This method is useful in calculating the transport coefficients in a Tokamak plasma confinement device. The particle density and temperature are shown to be a constant on a magnetic flux surface. Transport equations are given for the total particle flux and total energy flux crossing a closed toroidal surface. Also transport equations are given for the toroidal magnetic flux. A computer code was written to calculate the transport coefficients for a three species plasma, electrons and two species of ions. This is useful for calculating the transport coefficients of a plasma which contains impurities. It was found that the particle and energy transport coefficients are increased by a large amount, and the transport coefficients for the toroidal magnetic field are reduced by a small amount. For example, a deuterium plasma with 1.3 percent oxygen, one of the particle transport coefficients is increased by a factor of about four. The transport coefficients for the toroidal magnetic flux are reduced by about 20 percent. The increase in the particle transport coefficient is due to the collisional scattering of the deuterons by the heavy oxygen ions which is larger than the deuteron electron scattering, the normal process for particle transport in a two species plasma. The reduction in the toroidal magnetic flux transport coefficients are left unexplained
Díaz-de-Mera, Yolanda; Aranda, Alfonso; Bravo, Iván; Rodríguez, Diana; Rodríguez, Ana; Moreno, Elena
2008-10-01
The adverse environmental impacts of chlorinated hydrocarbons on the Earth's ozone layer have focused attention on the effort to replace these compounds by nonchlorinated substitutes with environmental acceptability. Hydrofluoroethers (HFEs) and fluorinated alcohols are currently being introduced in many applications for this purpose. Nevertheless, the presence of a great number of C-F bonds drives to atmospheric long-lived compounds with infrared absorption features. Thus, it is necessary to improve our knowledge about lifetimes and global warming potentials (GWP) for these compounds in order to get a complete evaluation of their environmental impact. Tropospheric degradation is expected to be initiated mainly by OH reactions in the gas phase. Nevertheless, Cl atoms reaction may also be important since rate constants are generally larger than those of OH. In the present work, we report the results obtained in the study of the reactions of Cl radicals with HFE-7000 (CF(3)CF(2)CF(2)OCH(3)) (1) and its isomer CF(3)CF(2)CF(2)CH(2)OH (2). Kinetic rate coefficients with Cl atoms have been measured using the discharge flow tube-mass spectrometric technique at 1 Torr of total pressure. The reactions of these chlorofluorocarbons (CFCs) substitutes have been studied under pseudo-first-order kinetic conditions in excess of the fluorinated compounds over Cl atoms. The temperature ranges were 266-333 and 298-353 K for reactions of HFE-7000 and CF(3)CF(2)CF(2)CH(2)OH, respectively. The measured room temperature rate constants were k(Cl+CF(3)CF(2)CF(2)OCH(3)) = (1.24 +/- 0.28) x 10(-13) cm(3) molecule(-1) s(-1)and k(Cl+CF(3)CF(2)CF(2)CH(2)OH) = (8.35 +/- 1.63) x 10(-13) cm(3) molecule(-1) s(-1) (errors are 2sigma + 10% to cover systematic errors). The Arrhenius expression for reaction 1 was k (1)(266-333 K) = (6.1 +/- 3.8) x 10(-13)exp[-(445 +/- 186)/T] cm(3) molecule(-1) s(-1) and k (2)(298-353 K) = (1.9 +/- 0.7) x 10(-12)exp[-(244 +/- 125)/T] cm(3) molecule(-1) s(-1) (errors
On some properties of SU(3 fusion coefficients
Directory of Open Access Journals (Sweden)
Robert Coquereaux
2016-11-01
Full Text Available Three aspects of the SU(3 fusion coefficients are revisited: the generating polynomials of fusion coefficients are written explicitly; some curious identities generalizing the classical Freudenthal–de Vries formula are derived; and the properties of the fusion coefficients under conjugation of one of the factors, previously analyzed in the classical case, are extended to the affine algebra suˆ(3 at finite level.
International Nuclear Information System (INIS)
Igamov, S.B.; Yarmukhamedov, R.
2007-01-01
A modified two-body potential approach is proposed for determination of both the asymptotic normalization coefficient (ANC) (or the respective nuclear vertex constant (NVC)) for the A+a->B (for the virtual decay B->A+a) from an analysis of the experimental S-factor for the peripheral direct capture a+A->B+γ reaction and the astrophysical S-factor, S(E), at low experimentally inaccessible energy regions. The approach proposed involves two additional conditions which verify the peripheral character of the considered reaction and expresses S(E) in terms of the ANC. The connection between NVC (ANC) and the effective range parameters for Aa-scattering is derived. To test this approach we reanalyse the precise experimental astrophysical S-factors for t+α->Li7+γ reaction at energies E= Li7(g.s.), α+t->Li7(0.478 MeV) and of S(E) at E=<50 keV. These ANC values have been used for getting information about the ''indirect'' measured values of the effective range parameters and the p-wave phase shift for αt-scattering in the energy range of 100-bar E-bar 180 keV
Micro- and macroscale coefficients of friction of cementitious materials
International Nuclear Information System (INIS)
Lomboy, Gilson; Sundararajan, Sriram; Wang, Kejin
2013-01-01
Millions of metric tons of cementitious materials are produced, transported and used in construction each year. The ease or difficulty of handling cementitious materials is greatly influenced by the material friction properties. In the present study, the coefficients of friction of cementitious materials were measured at the microscale and macroscale. The materials tested were commercially-available Portland cement, Class C fly ash, and ground granulated blast furnace slag. At the microscale, the coefficient of friction was determined from the interaction forces between cementitious particles using an Atomic Force Microscope. At the macroscale, the coefficient of friction was determined from stresses on bulk cementitious materials under direct shear. The study indicated that the microscale coefficient of friction ranged from 0.020 to 0.059, and the macroscale coefficient of friction ranged from 0.56 to 0.75. The fly ash studied had the highest microscale coefficient of friction and the lowest macroscale coefficient of friction. -- Highlights: •Microscale (interparticle) coefficient of friction (COF) was determined with AFM. •Macroscale (bulk) COF was measured under direct shear. •Fly ash had the highest microscale COF and the lowest macroscale COF. •Portland cement against GGBFS had the lowest microscale COF. •Portland cement against Portland cement had the highest macroscale COF
Diffusion coefficient of three-dimensional Yukawa liquids
International Nuclear Information System (INIS)
Dzhumagulova, K. N.; Ramazanov, T. S.; Masheeva, R. U.
2013-01-01
The purpose of this work is an investigation of the diffusion coefficient of the dust component in complex plasma. The computer simulation of the Yukawa liquids was made on the basis of the Langevin equation, which takes into account the influence of buffer plasma on the dust particles dynamics. The Green–Kubo relation was used to calculate the diffusion coefficient. Calculations of the diffusion coefficient for a wide range of the system parameters were performed. Using obtained numerical data, we constructed the interpolation formula for the diffusion coefficient. We also show that the interpolation formula correctly describes experimental data obtained under microgravity conditions
Coefficients of viscosity for heavy impurity element in tokamak
Energy Technology Data Exchange (ETDEWEB)
El-Sharif, R N; Bekhit, A M [Plasma Physics dept., NRC, Atomic energy Authority, Cairo, (Egypt)
1997-12-31
The transport of heavy impurity element in to tokamak was studied theoretically. The viscosity coefficients of chromium impurities has been calculated in 13 and 21 moment approximation, in the limit of strong fields where is the gyrofrequency of species it was found that the off diagonal coefficient approximately tends to zero. This means that the friction force in the off-diagonal direction is very small, for the perpendicular viscosity coefficient the two approximation coincide to each other. 3 figs.
An Investigation of the Sampling Distributions of Equating Coefficients.
Baker, Frank B.
1996-01-01
Using the characteristic curve method for dichotomously scored test items, the sampling distributions of equating coefficients were examined. Simulations indicate that for the equating conditions studied, the sampling distributions of the equating coefficients appear to have acceptable characteristics, suggesting confidence in the values obtained…
Analytical scheme calculations of angular momentum coupling and recoupling coefficients
Deveikis, A.; Kuznecovas, A.
2007-03-01
We investigate the Scheme programming language opportunities to analytically calculate the Clebsch-Gordan coefficients, Wigner 6j and 9j symbols, and general recoupling coefficients that are used in the quantum theory of angular momentum. The considered coefficients are calculated by a direct evaluation of the sum formulas. The calculation results for large values of quantum angular momenta were compared with analogous calculations with FORTRAN and Java programming languages.
Analytical scheme calculations of angular momentum coupling and recoupling coefficients
International Nuclear Information System (INIS)
Deveikis, A.; Kuznecovas, A.
2007-01-01
We investigate the Scheme programming language opportunities to analytically calculate the Clebsch-Gordan coefficients, Wigner 6j and 9j symbols, and general recoupling coefficients that are used in the quantum theory of angular momentum. The considered coefficients are calculated by a direct evaluation of the sum formulas. The calculation results for large values of quantum angular momenta were compared with analogous calculations with FORTRAN and Java programming languages
On the Connection Coefficients of the Chebyshev-Boubaker Polynomials
Directory of Open Access Journals (Sweden)
Paul Barry
2013-01-01
Full Text Available The Chebyshev-Boubaker polynomials are the orthogonal polynomials whose coefficient arrays are defined by ordinary Riordan arrays. Examples include the Chebyshev polynomials of the second kind and the Boubaker polynomials. We study the connection coefficients of this class of orthogonal polynomials, indicating how Riordan array techniques can lead to closed-form expressions for these connection coefficients as well as recurrence relations that define them.
Calculation of transport coefficients in an axisymmetric plasma
International Nuclear Information System (INIS)
Shumaker, D.E.
1977-01-01
A method of calculating the transport coefficient in an axisymmetric toroidal plasma is presented. This method is useful in calculating the transport coefficients in a Tokamak plasma confinement device. The particle density and temperature are shown to be a constant on a magnetic flux surface. Transport equations are given for the total particle flux and total energy flux crossing a closed toroidal surface. Also transport equations are given for the toroidal magnetic flux. A computer code was written to calculate the transport coefficients for a three species plasma, electrons and two species of ions. This is useful for calculating the transport coefficients of a plasma which contains impurities. It was found that the particle and energy transport coefficients are increased by a large amount, and the transport coefficients for the toroidal magnetic field are reduced by a small amount
Theoretical investigation of the extinction coefficient of magnetic fluid
Energy Technology Data Exchange (ETDEWEB)
Fang Xiaopeng; Xuan Yimin, E-mail: ymxuan@mail.njust.edu.cn; Li Qiang [Nanjing University of Science and Technology, School of Energy and Power Engineering (China)
2013-05-15
A new theoretical approach for calculating the extinction coefficient of magnetic fluid is proposed, which is based on molecular dynamics (MD) simulation and T-matrix method. By means of this approach, the influence of particle diameter, particle volume fraction, and external magnetic filed on the extinction coefficient of magnetic fluid is investigated. The results show that the extinction coefficient of the magnetic fluid linearly increases with increase in the particle volume fraction. For a given particle volume fraction, the extinction coefficient increases with increase in the particle diameter which varies from 5 to 20 nm. When a uniform external magnetic filed is applied to the magnetic fluid, the extinction coefficient of the magnetic fluid presents an anisotropic feature. These results agree well with the reported experimental results. The proposed approach is applicable to investigating the optical properties of magnetic fluids.
Clebsch-Gordan and Racah coefficients of SUpq(2)
International Nuclear Information System (INIS)
Kachurik, I.I.
1993-01-01
Explicit expressions for the Clebsch-Gordan coefficients and for the Racah coefficients of the two-parametric quantum algebra SU pq (2) are derived. They are given as finite sums and as terminating basic hypergeometric functions 3 φ 2 and 4 φ 3 . It is indicated how other expressions for these coefficients can be derived with the help of basic hypergeometric functions. (author). 11 refs
Wavelet Correlation Coefficient of 'strongly correlated' financial time series
Razdan, Ashok
2003-01-01
In this paper we use wavelet concepts to show that correlation coefficient between two financial data's is not constant but varies with scale from high correlation value to strongly anti-correlation value This studies is important because correlation coefficient is used to quantify degree of independence between two variables. In econophysics correlation coefficient forms important input to evolve hierarchial tree and minimum spanning tree of financial data.
Kinetic theory of the interdiffusion coefficient in dense plasmas
International Nuclear Information System (INIS)
Boercker, D.B.
1986-08-01
Naive applications of Spitzer's theory to very dense plasmas can lead to negative diffusion coefficients. The interdiffusion coefficients in Binary Ionic Mixtures (two species of point ions in a uniform neutralizing background) have been calculated recently using molecular dynamics techniques. These calculations can provide useful benchmarks for theoretical evaluations of the diffusion coefficient in dense plasma mixtures. This paper gives a brief description of a kinetic theoretic approximation to the diffusion coefficient which generalizes Spitzer to high density and is in excellent agreement with the computer simulations. 15 refs., 1 fig., 2 tabs
Calculation of effective absorption coefficient for aerosols of internal mixture
International Nuclear Information System (INIS)
Xu Bo; Huang Yinbo; Fan Chengyu; Qiao Chunhong
2012-01-01
The effective absorption coefficient with time of strong absorbing aerosol made of carbon dusts and water of internal mixture is analyzed, and the influence of different wavelengths and radius ratios on it is discussed. The shorter the wavelength is, the larger the effective absorption coefficient is , and more quickly it increases during 1-100 μs, and the largest increase if 132.65% during 1-100 μs. Different ratios between inner and outer radius have large influence on the effective absorption coefficient. The larger the ratio is, the larger the effective absorption coefficient is, and more quickly it increases during 1-100 μs. The increase of the effective absorption coefficient during 1-100 μs is larger than that during 100-1000 μs, and the largest increase is 138.66% during 1-100 μs. (authors)
Structural relaxation and thermal conductivity coefficient of liquids
International Nuclear Information System (INIS)
Abdurasulov, A.
1992-01-01
Present article is devoted to structural relaxation and thermal conductivity coefficient of liquids. The thermoelastic properties of liquids were studied taking into account the contribution of translational and structural relaxation. The results of determination of dynamic coefficient of thermal conductivity of liquids taking into account the contribution of translational and structural relaxation are presented.
Taylor coefficients and coefficient multipliers of Hardy and Bergman-type spaces
Jevtić, Miroljub; Arsenović, Miloš
2016-01-01
This book provides a systematic overview of the theory of Taylor coefficients of functions in some classical spaces of analytic functions and especially of the coefficient multipliers between spaces of Hardy type. Offering a comprehensive reference guide to the subject, it is the first of its kind in this area. After several introductory chapters covering the basic material, a large variety of results obtained over the past 80 years, including the most recent ones, are treated in detail. Several chapters end with discussions of practical applications and related topics that graduate students and experts in other subjects may find useful for their own purposes. Thus, a further aim of the book is to communicate to non-specialists some concrete facts that may be of value in their own work. The book can also be used as a textbook or a supplementary reference for an advanced graduate course. It is primarily intended for specialists in complex and functional analysis, graduate students, and experts in other related...
International Nuclear Information System (INIS)
Linjun, Xie; Guohong, Xue; Ming, Zhang
2016-01-01
Graphical abstract: HDS stress coefficient test apparatus. - Highlights: • This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. • The mathematical relation between the load and the strain is obtained about the HDS, and the mathematical model of the stress coefficient and the friction coefficient is established. So, a set of test apparatuses for obtaining the stress coefficient is designed according to the model scaling criterion and the friction coefficient of the K1000 HDS is calculated to be 0.336 through the obtained stress coefficient. • The relation curve between the theoretical load and the friction coefficient is obtained through analysis and indicates that the change of the friction coefficient f would influence the pretightening load under the condition of designed stress. The necessary pretightening load in the design process is calculated to be 5469 kN according to the obtained friction coefficient. Therefore, the friction coefficient and the pretightening load under the design conditions can provide accurate pretightening data for the analysis and design of the reactor HDS according to the operations. - Abstract: This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. By carrying out tests and researches through a stress testing technique, P–σ curves in loading and unloading processes of the HDS are obtained and the stress coefficient k f of the HDS is obtained. So, the
Energy Technology Data Exchange (ETDEWEB)
Linjun, Xie, E-mail: linjunx@zjut.edu.cn [College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Guohong, Xue; Ming, Zhang [Shanghai Nuclear Engineering Research & Design Institute, Shanghai 200233 (China)
2016-08-01
Graphical abstract: HDS stress coefficient test apparatus. - Highlights: • This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. • The mathematical relation between the load and the strain is obtained about the HDS, and the mathematical model of the stress coefficient and the friction coefficient is established. So, a set of test apparatuses for obtaining the stress coefficient is designed according to the model scaling criterion and the friction coefficient of the K1000 HDS is calculated to be 0.336 through the obtained stress coefficient. • The relation curve between the theoretical load and the friction coefficient is obtained through analysis and indicates that the change of the friction coefficient f would influence the pretightening load under the condition of designed stress. The necessary pretightening load in the design process is calculated to be 5469 kN according to the obtained friction coefficient. Therefore, the friction coefficient and the pretightening load under the design conditions can provide accurate pretightening data for the analysis and design of the reactor HDS according to the operations. - Abstract: This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. By carrying out tests and researches through a stress testing technique, P–σ curves in loading and unloading processes of the HDS are obtained and the stress coefficient k{sub f} of the HDS is obtained. So, the
Diffusion coefficients gases, dissolved in fluid of NPPs circulation contours
International Nuclear Information System (INIS)
Piontkovskij, A.I.
2000-01-01
In article is brought analysis of diverse gases diffusion coefficients computation methods, dissolved in liquid. On the basis of this analysis and treatment of being equalizations for concrete gases and certain parameters offers universal diffusion coefficients determination dependence for diverse gases in wide range of parameters, circulation contours typical for work NPP
Design of wind turbine airfoils based on maximum power coefficient
DEFF Research Database (Denmark)
Cheng, Jiangtao; Chen, Jin; Cheng, Jiangtao
2010-01-01
Based on the blade element momentum (BEM) theory, the power coefficient of a wind turbine can be expressed in function of local tip speed ratio and lift-drag ratio. By taking the power coefficient in a predefined range of angle of attack as the final design objective and combining with an airfoil...
Testing the Difference of Correlated Agreement Coefficients for Statistical Significance
Gwet, Kilem L.
2016-01-01
This article addresses the problem of testing the difference between two correlated agreement coefficients for statistical significance. A number of authors have proposed methods for testing the difference between two correlated kappa coefficients, which require either the use of resampling methods or the use of advanced statistical modeling…
Coefficients of tracer transfer through membranes. Pt. 7
Energy Technology Data Exchange (ETDEWEB)
Dorabialska, A; Hawlicka, E; Plonka, A [Politechnika Lodzka (Poland)
1974-01-01
The doubled value of the tracer transfer coefficient in the self-diffusion process is equal to the sum of tracer transfer coefficients in the diffusion and interfusion processes. The fundamental phenomenological relation can be deduced for the coefficients of tracer transfer between two phases of electrolyte solutions spearated by a virtual boundary. Indeed, the doubled value of the tracer mobility in the self-diffusion experiment (no concentration gradient of the traced substance) is equal to the sum of the tracer mobilities in the diffusion (tracer movement along with the concentration gradient of the traced substance) and interfusion experiments (tracer movement against the concentration gradient of the traced substance). Thus the doubled value of the tracer transfer coefficient in the self-diffusion process should be equal to the sum of tracer transfer coefficients in the diffusion and interfusion processes. The experimental verification of that fundamental relation is presented.
Permeability dependence of streaming potential coefficient in porous media
Thanh, L.D.; Sprik, R.
2015-01-01
In theory, the streaming potential coefficient depends not only on the zeta potential but also on the permeability of the rocks that partially determines the surface conductivity of the rocks. However, in practice, it is hard to show the permeability dependence of streaming potential coefficients
Graphical Solution of the Monic Quadratic Equation with Complex Coefficients
Laine, A. D.
2015-01-01
There are many geometrical approaches to the solution of the quadratic equation with real coefficients. In this article it is shown that the monic quadratic equation with complex coefficients can also be solved graphically, by the intersection of two hyperbolas; one hyperbola being derived from the real part of the quadratic equation and one from…
CHEMICAL REACTIONS ON ADSORBING SURFACE: KINETIC LEVEL OF DESCRIPTION
Directory of Open Access Journals (Sweden)
P.P.Kostrobii
2003-01-01
Full Text Available Based on the effective Hubbard model we suggest a statistical description of reaction-diffusion processes for bimolecular chemical reactions of gas particles adsorbed on the metallic surface. The system of transport equations for description of particles diffusion as well as reactions is obtained. We carry out the analysis of the contributions of all physical processes to the formation of diffusion coefficients and chemical reactions constants.
Approximation of the Frame Coefficients using Finite Dimensional Methods
DEFF Research Database (Denmark)
Christensen, Ole; Casazza, P.
1997-01-01
_i \\}_{i=1}^{n}$ of the frame and theorthogonal projection $P_n$ onto its span. For $f \\in \\h ,P_nf$ has a representation as a linear combination of $f_i , i=1,2,..n,$and the corresponding coefficients can be calculated using finite dimensionalmethods. We find conditions implying that those coefficients...
Confidence bounds for normal and lognormal distribution coefficients of variation
Steve Verrill
2003-01-01
This paper compares the so-called exact approach for obtaining confidence intervals on normal distribution coefficients of variation to approximate methods. Approximate approaches were found to perform less well than the exact approach for large coefficients of variation and small sample sizes. Web-based computer programs are described for calculating confidence...
Stochastic Modelling of the Diffusion Coefficient for Concrete
DEFF Research Database (Denmark)
Thoft-Christensen, Palle
In the paper, a new stochastic modelling of the diffusion coefficient D is presented. The modelling is based on physical understanding of the diffusion process and on some recent experimental results. The diffusion coefficients D is strongly dependent on the w/c ratio and the temperature....
Explicit solutions of two nonlinear dispersive equations with variable coefficients
International Nuclear Information System (INIS)
Lai Shaoyong; Lv Xiumei; Wu Yonghong
2008-01-01
A mathematical technique based on an auxiliary equation and the symbolic computation system Matlab is developed to construct the exact solutions for a generalized Camassa-Holm equation and a nonlinear dispersive equation with variable coefficients. It is shown that the variable coefficients of the derivative terms in the equations cause the qualitative change in the physical structures of the solutions
Minimum wall pressure coefficient of orifice plate energy dissipater
Directory of Open Access Journals (Sweden)
Wan-zheng Ai
2015-01-01
Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.
Multilayer Network Analysis of Nuclear Reactions
Zhu, Liang; Ma, Yu-Gang; Chen, Qu; Han, Ding-Ding
2016-08-01
The nuclear reaction network is usually studied via precise calculation of differential equation sets, and much research interest has been focused on the characteristics of nuclides, such as half-life and size limit. In this paper, however, we adopt the methods from both multilayer and reaction networks, and obtain a distinctive view by mapping all the nuclear reactions in JINA REACLIB database into a directed network with 4 layers: neutron, proton, 4He and the remainder. The layer names correspond to reaction types decided by the currency particles consumed. This combined approach reveals that, in the remainder layer, the β-stability has high correlation with node degree difference and overlapping coefficient. Moreover, when reaction rates are considered as node strength, we find that, at lower temperatures, nuclide half-life scales reciprocally with its out-strength. The connection between physical properties and topological characteristics may help to explore the boundary of the nuclide chart.
Riesz frames and approximation of the frame coefficients
DEFF Research Database (Denmark)
Casazza, P.; Christensen, Ole
1998-01-01
A frame is a fmaily {f i } i=1 ∞ of elements in a Hilbert space with the property that every element in can be written as a (infinite) linear combination of the frame elements. Frame theory describes how one can choose the corresponding coefficients, which are called frame coefficients. From...... the mathematical point of view this is gratifying, but for applications it is a problem that the calculation requires inversion of an operator on . The projection method is introduced in order to avoid this problem. The basic idea is to consider finite subfamilies {f i } i=1 n of the frame and the orthogonal...... projection Pn onto its span. For has a representation as a linear combination of fi, i=1,2,..., n and the corresponding coefficients can be calculated using finite dimensional methods. We find conditions implying that those coefficients converge to the correct frame coefficients as n→∞, in which case we have...
Activity coefficients of electrons and holes in semiconductors
International Nuclear Information System (INIS)
Orazem, M.E.; Newman, J.
1984-01-01
Dilute-solution transport equations with constant activity coefficients are commonly used to model semiconductors. These equations are consistent with a Boltzmann distribution and are invalid in regions where the species concentration is close to the respective site concentration. A more rigorous treatment of transport in a semiconductor requires activity coefficients which are functions of concentration. Expressions are presented for activity coefficients of electrons and holes in semiconductors for which conduction- and valence-band energy levels are given by the respective bandedge energy levels. These activity coefficients are functions of concentration and are thermodynamically consistent. The use of activity coefficients in macroscopic transport relationships allows a description of electron transport in a manner consistent with the Fermi-Dirac distribution
Visualising the Roots of Quadratic Equations with Complex Coefficients
Bardell, Nicholas S.
2014-01-01
This paper is a natural extension of the root visualisation techniques first presented by Bardell (2012) for quadratic equations with real coefficients. Consideration is now given to the familiar quadratic equation "y = ax[superscript 2] + bx + c" in which the coefficients "a," "b," "c" are generally…
The κ-Generalizations of Stirling Approximation and Multinominal Coefficients
Directory of Open Access Journals (Sweden)
Tatsuaki Wada
2013-11-01
Full Text Available Stirling approximation of the factorials and multinominal coefficients are generalized based on the κ-generalized functions introduced by Kaniadakis. We have related the κ-generalized multinominal coefficients to the κ-entropy by introducing a new κ-product operation, which exists only when κ ≠ 0.
Modeling of Reaction Calorimeter
Farzad, Reza
2014-01-01
The purpose of this project was to model the reaction calorimeter in order to calculate the heat of absorption which is the most important parameter in this work. Reaction calorimeter is an apparatus which is used in measuring the heat of absorption of CO2 as well as the total pressure in vapor phase based on vapor-liquid equilibrium state. Mixture of monoethanolamine (MEA) and water was used as a solvent to absorb the CO2.Project was divided in to three parts in order to make the programming...
Chemical kinetics of gas reactions
Kondrat'Ev, V N
2013-01-01
Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema
Influence of effective stress coefficient on mechanical failure of chalk
DEFF Research Database (Denmark)
Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Hjuler, M.L.
2012-01-01
The Effective stress coefficient is a measure of how chalk grains are connected with each other. The stiffness of chalk may decrease if the amount of contact cements between the grains decreases, which may lead to an increase of the effective stress coefficient. We performed CO2 injection in chal...... precise failure strength of chalk during changed stress state and under the influence of chemically reactive fluids during production of hydrocarbon and geological storage CO2....
International Nuclear Information System (INIS)
Al-Abdullah, T.; Carstoiu, F.; Chen, X.; Clark, H. L.; Fu, C.; Gagliardi, C. A.; Lui, Y.-W.; Mukhamedzhanov, A.; Tabacaru, G.; Tokimoto, Y.; Trache, L.; Tribble, R. E.
2010-01-01
The production of 22 Na in ONe novae can be influenced by the 22 Mg(p,γ) 23 Al reaction. To investigate this reaction rate at stellar energies, we have determined the asymptotic normalization coefficient (ANC) for 22 Mg+p→ 23 Al through measurements of the ANCs in the mirror nuclear system 22 Ne+n→ 23 Ne. The peripheral neutron-transfer reactions 13 C( 12 C, 13 C) 12 C and 13 C( 22 Ne, 23 Ne) 12 C were studied. The identical entrance and exit channels of the first reaction make it possible to extract independently the ground-state ANC in 13 C. Our experiment gives C p 1/2 2 ( 13 C)=2.24±0.11 fm -1 , which agrees with the value obtained from several previous measurements. The weighted average for all the obtained C p 1/2 2 is 2.31±0.08 fm -1 . This value is adopted to be used in obtaining the ANCs in 23 Ne. The differential cross sections for the reaction 13 C( 22 Ne, 23 Ne) 12 C leading to the J π =5/2 + and 1/2 + states in 23 Ne have been measured at 12 MeV/u. Optical model parameters for use in the DWBA calculations were obtained from measurements of the elastic scatterings 22 Ne+ 13 C and 22 Ne+ 12 C. The extracted ANC for the ground state in 23 Ne, C d 5/2 2 =0.86±0.08±0.12 fm -1 , is converted to its corresponding value in 23 Al using mirror symmetry to give C d 5/2 2 ( 23 Al)=(4.63±0.77)x10 3 fm -1 . The astrophysical S factor S(0) for the 22 Mg(p,γ) reaction was determined to be 0.96±0.11 keV b. The consequences for nuclear astrophysics are discussed.
Effect of applied mechanical stress on absorption coefficient of compounds
Energy Technology Data Exchange (ETDEWEB)
Gupta, Manoj Kumar, E-mail: mkgupta.sliet@gmail.com [Department of Applied Sciences, Bhai Gurdas Institute of Engineering and Technology, Sangrur (India); Singh, Gurinderjeet; Dhaliwal, A. S.; Kahlon, K. S. [Department of Physics, Sant Longowal Institute of Engineering & Technology Deemed University, Longowal (Sangrur) India-148106 (India)
2015-08-28
The absorption coefficient of given materials is the parameter required for the basic information. The measurement of absorption coefficient of compounds Al{sub 2}O{sub 3}, CaCO{sub 3}, ZnO{sub 2}, SmO{sub 2} and PbO has been taken at different incident photon energies 26, 59.54, 112, 1173, 1332keV. The studies involve the measurements of absorption coefficient of the self supporting samples prepared under different mechanical stress. This mechanical stress is render in terms of pressure up to 0-6 ton by using hydraulic press. Measurements shows that absorption coefficient of a material is directly proportional to applied mechanical stress on it up to some extent then become independent. Experimentally measured results are in fairly good agreement with in theoretical values obtained from WinXCOM.
On separation of exchange term from the coefficient of the ...
Indian Academy of Sciences (India)
Magnetoelectroelastics; exchange coefficient; magnetoelectric effect; piezoelectric effect; piezomagnetic effect. PACS Nos 51.40.+p; 72.55.+s. Magnetoelectroelastics, also known as piezoelectromagnetic smart materials, actually possess magnetoelectric, piezomagnetic, and piezoelectric effects. In this class of mag-.
Hijikata, Hayato; Kozawa, Takahiro; Tagawa, Seiichi; Takei, Satoshi
2009-06-01
A bottom extreme-ultraviolet-sensitive coating (BESC) for evaluation of the absorption coefficients of ultrathin films such as extreme ultraviolet (EUV) resists was developed. This coating consists of a polymer, crosslinker, acid generator, and acid-responsive chromic dye and is formed by a conventional spin-coating method. By heating the film after spin-coating, a crosslinking reaction is induced and the coating becomes insoluble. A typical resist solution can be spin-coated on a substrate covered with the coating film. The evaluation of the linear absorption coefficients of polymer films was demonstrated by measuring the EUV absorption of BESC substrates on which various polymers were spin-coated.
Determination of rolling resistance coefficient based on normal tyre stiffness
Rykov, S. P.; Tarasuyk, V. N.; Koval, V. S.; Ovchinnikova, N. I.; Fedotov, A. I.; Fedotov, K. V.
2018-03-01
The purpose of the article is to develop analytical dependence of wheel rolling resistance coefficient based on the mathematical description of normal tyre stiffness. The article uses the methods of non-holonomic mechanics and plane section methods. The article shows that the abscissa of gravity center of tyre stiffness expansion by the length of the contact area is the shift of normal road response. It can be used for determining rolling resistance coefficient. When determining rolling resistance coefficient using ellipsis and power function equations, one can reduce labor costs for testing and increase assessment accuracy.
Questionnaire on the measurement condition of distribution coefficient
International Nuclear Information System (INIS)
Takebe, Shinichi; Kimura, Hideo; Matsuzuru, Hideo
2001-05-01
The distribution coefficient is used for various transport models to evaluate the migration behavior of radionuclides in the environment and is very important parameter in environmental impact assessment of nuclear facility. The questionnaire was carried out for the purpose of utilizing for the proposal of the standard measuring method of distribution coefficient. This report is summarized the result of questionnairing on the sampling methods and storage condition, the pretreatment methods, the analysis items in the physical/chemical characteristics of the sample, and the distribution coefficient measuring method and the measurement conditions in the research institutes within country. (author)
The static pressure and temperature coefficients of laboratory standard microphones
DEFF Research Database (Denmark)
Rasmussen, Knud
1999-01-01
, for a given type of microphone, can be described by a single function when the coefficients are normalized by their low-frequency value and the frequency is normalized with respect to the individual resonance frequency of the microphone. The theoretical results are supported by experimentally determined...... on an extended lumped parameter representation of the mechanical and acoustic elements of the microphone. The extension involves the frequency dependency of the dynamic diaphragm mass and stiffness as well as a first-order approximation of resonances in the back cavity. It was found that each coefficient...... coefficients for about twenty samples of microphone types B&K 4160 and B&K 4180....
Overview of models allowing calculation of activity coefficients
Energy Technology Data Exchange (ETDEWEB)
Jaussaud, C.; Sorel, C
2004-07-01
Activity coefficients must be estimated to accurately quantify the extraction equilibrium involved in spent fuel reprocessing. For these calculations, binary data are required for each electrolyte over a concentration range sometimes exceeding the maximum solubility. The activity coefficients must be extrapolated to model the behavior of binary supersaturated aqueous solution. According to the bibliography, the most suitable models are based on the local composition concept. (authors)
Static pressure and temperature coefficients of laboratory standard microphones
DEFF Research Database (Denmark)
Rasmussen, Knud
1996-01-01
of the microphone. The static pressure and temperature coefficients were determined experimentally for about twenty samples of type BK 4160 and BK 4180 microphones. The results agree almost perfectly with the predictions for BK 4160, while some modifications of the lumped parameter values are called for to make......-order approximation of resonances in the back cavity. It was found that each of the coefficients, for a given type of microphone, can be expressed by a single function when the coefficients are normalized by their low-frequency value and the frequency axis normalized by the individual resonance frequency...
Reaction schemes of immunoanalysis
International Nuclear Information System (INIS)
Delaage, M.; Barbet, J.
1991-01-01
The authors apply a general theory for multiple equilibria to the reaction schemes of immunoanalysis, competition and sandwich. This approach allows the manufacturer to optimize the system and provide the user with interpolation functions for the standard curve and its first derivative as well, thus giving access to variance [fr
Measurement of chemical diffusion coefficients in liquid binary alloys
International Nuclear Information System (INIS)
Keita, M.; Steinemann, S.; Kuenzi, H.U.
1976-01-01
New measurements of the chemical diffusion coefficient in liquid binary alloys are presented. The wellknown geometry of the 'capillary-reservoir' is used and the concentration is obtained from a resistivity measurement. The method allows to follow continuously the diffusion process in the liquid state. A precision of at least 10% in the diffusion coefficient is obtained with a reproductibility better than 5%. The systems Hg-In, Al-Sn, Al-Si have been studied. Diffusion coefficients are obtained as a function of temperature, concentration, and geometrical factors related to the capillary (diameter, relative orientation of density gradient and gravity). (orig.) [de
Robust Stabilization of Nonlinear Systems with Uncertain Varying Control Coefficient
Directory of Open Access Journals (Sweden)
Zaiyue Yang
2014-01-01
Full Text Available This paper investigates the stabilization problem for a class of nonlinear systems, whose control coefficient is uncertain and varies continuously in value and sign. The study emphasizes the development of a robust control that consists of a modified Nussbaum function to tackle the uncertain varying control coefficient. By such a method, the finite-time escape phenomenon has been prevented when the control coefficient is crossing zero and varying its sign. The proposed control guarantees the asymptotic stabilization of the system and boundedness of all closed-loop signals. The control performance is illustrated by a numerical simulation.
Measuring device for the temperature coefficient of reactor moderators
International Nuclear Information System (INIS)
Nakano, Yuzo.
1987-01-01
Purpose: To rapidly determine by automatic calculation the temperature coefficient for moderators which has been determined so far by a log of manual processings. Constitution: Each of signals from a control rod position indicator, a reactor reactivity, instrument and moderator temperature meter are inputted, and each of the signals and designed valued for the doppler temperature coefficients are stored. Recurling calculation is conducted based on the reactivity and the moderator temperature at an interval where the temperature changes of the moderators are equalized at an identical control rod position, to determine isothermic coefficient. Then, the temperature coefficient for moderator are calculated from the isothermic coefficient and the doppler temperature coefficient. The relationship between the reactivity and the moderator temperature is plotted on a X-Y recorder. The stored signals and the calculated temperature coefficient for moderators are sequentially displayed and the results are printed out when the measurement is completed. According to the present device, since the real time processing is conducted, the processing time can be shortened remarkably. Accordingly, it is possible to save the man power for the test of the nuclear reactor and improve the reactor operation performance. (Kamimura, M.)
Papadimitriou, Vassileios C; Karafas, Emmanuel S; Gierczak, Tomasz; Burkholder, James B
2015-07-16
The gas-phase CH3CO + O2 reaction is known to proceed via a chemical activation mechanism leading to the formation of OH and CH3C(O)OO radicals via bimolecular and termolecular reactive channels, respectively. In this work, rate coefficients, k, for the CH3CO + O2 reaction were measured over a range of temperature (241-373 K) and pressure (0.009-600 Torr) with He and N2 as the bath gas and used to characterize the bi- and ter-molecular reaction channels. Three independent experimental methods (pulsed laser photolysis-laser-induced fluorescence (PLP-LIF), pulsed laser photolysis-cavity ring-down spectroscopy (PLP-CRDS), and a very low-pressure reactor (VLPR)) were used to characterize k(T,M). PLP-LIF was the primary method used to measure k(T,M) in the high-pressure regime under pseudo-first-order conditions. CH3CO was produced by PLP, and LIF was used to monitor the OH radical bimolecular channel reaction product. CRDS, a complementary high-pressure method, measured k(295 K,M) over the pressure range 25-600 Torr (He) by monitoring the temporal CH3CO radical absorption following its production via PLP in the presence of excess O2. The VLPR technique was used in a relative rate mode to measure k(296 K,M) in the low-pressure regime (9-32 mTorr) with CH3CO + Cl2 used as the reference reaction. A kinetic mechanism analysis of the combined kinetic data set yielded a zero pressure limit rate coefficient, kint(T), of (6.4 ± 4) × 10(-14) exp((820 ± 150)/T) cm(3) molecule(-1) s(-1) (with kint(296 K) measured to be (9.94 ± 1.3) × 10(-13) cm(3) molecule(-1) s(-1)), k0(T) = (7.39 ± 0.3) × 10(-30) (T/300)(-2.2±0.3) cm(6) molecule(-2) s(-1), and k∞(T) = (4.88 ± 0.05) × 10(-12) (T/300)(-0.85±0.07) cm(3) molecule(-1) s(-1) with Fc = 0.8 and M = N2. A He/N2 collision efficiency ratio of 0.60 ± 0.05 was determined. The phenomenological kinetic results were used to define the pressure and temperature dependence of the OH radical yield in the CH3CO + O2 reaction. The
Non-linear Bayesian update of PCE coefficients
Litvinenko, Alexander
2014-01-06
Given: a physical system modeled by a PDE or ODE with uncertain coefficient q(?), a measurement operator Y (u(q), q), where u(q, ?) uncertain solution. Aim: to identify q(?). The mapping from parameters to observations is usually not invertible, hence this inverse identification problem is generally ill-posed. To identify q(!) we derived non-linear Bayesian update from the variational problem associated with conditional expectation. To reduce cost of the Bayesian update we offer a unctional approximation, e.g. polynomial chaos expansion (PCE). New: We apply Bayesian update to the PCE coefficients of the random coefficient q(?) (not to the probability density function of q).
Non-linear Bayesian update of PCE coefficients
Litvinenko, Alexander; Matthies, Hermann G.; Pojonk, Oliver; Rosic, Bojana V.; Zander, Elmar
2014-01-01
Given: a physical system modeled by a PDE or ODE with uncertain coefficient q(?), a measurement operator Y (u(q), q), where u(q, ?) uncertain solution. Aim: to identify q(?). The mapping from parameters to observations is usually not invertible, hence this inverse identification problem is generally ill-posed. To identify q(!) we derived non-linear Bayesian update from the variational problem associated with conditional expectation. To reduce cost of the Bayesian update we offer a unctional approximation, e.g. polynomial chaos expansion (PCE). New: We apply Bayesian update to the PCE coefficients of the random coefficient q(?) (not to the probability density function of q).
DEFF Research Database (Denmark)
Villadsen, John
2015-01-01
his chapter predicts the specific rates of reaction by means of a mathematical expression, the kinetics of the reaction. This expression can be derived through a mechanistic interpretation of an enzymatically catalyzed reaction, but it is essentially of empirical nature for cell reactions. The mo...
Seal assembly for materials with different coefficients of thermal expansion
Minford, Eric [Laurys Station, PA
2009-09-01
Seal assembly comprising (a) two or more seal elements, each element having having a coefficient of thermal expansion; and (b) a clamping element having a first segment, a second segment, and a connecting segment between and attached to the first and second segments, wherein the two or more seal elements are disposed between the first and second segments of the clamping element. The connecting segment has a central portion extending between the first segment of the clamping element and the second segment of the clamping element, and the connecting segment is made of a material having a coefficient of thermal expansion. The coefficient of thermal expansion of the material of the connecting segment is intermediate the largest and smallest of the coefficients of thermal expansion of the materials of the two or more seal elements.
Photooxidative reactions of psoralens
International Nuclear Information System (INIS)
Potapenko, A.Ya.; Sukhorukov, V.L.
1984-01-01
The mechanism and biological significance of photooxidative reactions of psoralens are reviewed. Skin-photosensitizing activities of bifunctional and monofunctional psoralens are compared. Antioxidants tocopherols and butilated hydroxytoluene inhibit photochemical reactions of psoralens responsible for induction of erythema. The same antioxidants do not inhibit PUVA-therapy of psriasis. Though psoralens can generate singlet oxygen under UVA-irradiation (315 - 400 nm), nevertheless singlet oxygen does not play significant role in 8-methoxypsoralen (8-MOP) sensitized photooxidation of tocopherol or dihydroxyphenylalanine (DOPA). SH-compounds enhance the rate of 8-MOP sensitized photooxidation of DOPA by a factor of four, simultaneously the rate of oxidation of SH-groups is enhanced many fold in the presence of DOPA. Under UVA-irradiation in organic solvents psoralens are photooxidized. Dimeric photooxidized psoralens are easily destructed in water medium, their destruction induce oxidation of unsaturated lipids and DOPA. (author)
Pearson's correlation coefficient in the theory of networks: A comment
Ahmed, Zafar; Kumar, Sachin
2018-01-01
In statistics, the Pearson correlation coefficient $r_{x,y}$ determines the degree of linear correlation between two variables and it is known that $-1 \\le r_{x,y} \\le 1$. In the theory of networks, a curious expression proposed in [PRL {\\bf 89} 208701 (2002)] for degree-degree correlation coefficient $r_{j_i,k_i}, i\\in [1,M]$ has been in use. We realize that the suggested form is the conventional Pearson's coefficient for $\\{(j_i,k_i), (k_i,j_i)\\}$ for $2M$ data points and hence it is rightl...
Raman spectroscopic study of reaction dynamics
MacPhail, R. A.
1990-12-01
The Raman spectra of reacting molecules in liquids can yield information about various aspects of the reaction dynamics. The author discusses the analysis of Raman spectra for three prototypical unimolecular reactions, the rotational isomerization of n-butane and 1,2-difluoroethane, and the barrierless exchange of axial and equatorial hydrogens in cyclopentane via pseudorotation. In the first two cases the spectra are sensitive to torsional oscillations of the gauche conformer, and yield estimates of the torsional solvent friction. In the case of cyclopentane, the spectra can be used to discriminate between different stochastic models of the pseudorotation dynamics, and to determine the relevant friction coefficients.
Use of appropriate absorption coefficients in gamma-ray dosimetry
International Nuclear Information System (INIS)
Gopinath, D.V.; Natarajan, A.; Subbaiah, K.V.
1985-01-01
The current use of the different types of absorption coefficients in the computation of γ-ray energy deposition rates and air dose is critically analyzed. Transport calculations are presented to bring out the errors associated with the use of different absorption coefficients. It is observed that except for source energies in the range of 0.3 to 3.0 MeV the consistent use of the absorption coefficient, μ/sub a/ results in an underestimate of the air dose everywhere and of energy deposition at regions away from source. The underestimate becomes more significant with increased atomic number (Z) of the medium. Based on the computations and analysis it is concluded that the absorption coefficients μ/sub a/ and μ/sub k/ are of very limited use in practical γ-ray dosimetry
Determination of BEACON Coupling Coefficients using data from Xenon transient
International Nuclear Information System (INIS)
Bozic, M.; Kurincic, B.
2007-01-01
NEK uses BEACO TM code (BEACO TM - Westinghouse Best Estimate Analyzer for Core Operating Nuclear) for core monitoring, analysis and core behaviour prediction. Coupling Coefficients determine relationship between core response and excore instrumentation. Measured power distribution using incore moveable detectors during Xenon transient with sufficient power axial offset change is the most important data for further analysis. Classic methodology and BEACO TM Conservative methodology using established Coupling Coefficients are compared on NPP Krsko case. BEACON TM Conservative methodology with predefined Coupling Coefficients is used as a surveillance tool for verification of relationship between core and excore instrumentation during power operation. (author)
Coefficient of electrical transport vacuum arc for metals and alloys
International Nuclear Information System (INIS)
Markov, G.V.; Ehjzner, B.A.
1998-01-01
In this article the authors propose formulas for estimation coefficient of electrical transport vacuum arc for metals and alloys. They also represent results of analysis principal physical processes which take place in cathode spot vacuum arc
Determination of optical absorption coefficient with focusing photoacoustic imaging.
Li, Zhifang; Li, Hui; Zeng, Zhiping; Xie, Wenming; Chen, Wei R
2012-06-01
Absorption coefficient of biological tissue is an important factor for photothermal therapy and photoacoustic imaging. However, its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique to quantify the target optical absorption coefficient. It utilizes the ratio of the amplitude of the peak signal from the top boundary of the target to that from the bottom boundary based on wavelet transform. This method is self-calibrating. Factors, such as absolute optical fluence, ultrasound parameters, and Grüneisen parameter, can be canceled by dividing the amplitudes of the two peaks. To demonstrate this method, we quantified the optical absorption coefficient of a target with various concentrations of an absorbing dye. This method is particularly useful to provide accurate absorption coefficient for predicting the outcomes of photothermal interaction for cancer treatment with absorption enhancement.
Solution of heat equation with variable coefficient using derive
CSIR Research Space (South Africa)
Lebelo, RS
2008-09-01
Full Text Available In this paper, the method of approximating solutions of partial differential equations with variable coefficients is studied. This is done by considering heat flow through a one-dimensional model with variable cross-sections. Two cases...
Technique for Determining Lock Coefficient of Differential "Quif"
Directory of Open Access Journals (Sweden)
A. B. Fominyh
2015-01-01
Full Text Available Increasing the traction qualities of cars on the black ice and snow-covered roads is a relevant task. There are two ways to solve this task, i.e. optimize distribution of the power stream between the driving wheels of the car; introduce a differential (differentials of the increased friction in transmission.Now, an installation of the increased friction differential in transmission is the most widespread measure to increase traction properties of cars. The differential of design "Quif" is one of such differentials. To estimate the efficiency degree of using such a differential is possible either experimentally or theoretically. In case of theoretically determined usefulness of this differential design, as an estimate indicator of the differential installation in transmission a coefficient of lock is accepted.The article considers an algorithm and a technique to calculate a lock coefficient of the differential design "Quif" allowing us to define numeric values of the lock coefficient of such differential at designing stage. It also considers how the lock coefficient depends on the gearing angle and tilt angle of the gear wheel teeth of differential. The given estimating algorithm of designated parameter of differential has more logical and compact structure with regard to the known ones. The lock coefficient values calculated by the offered technique differ from the experimental data by no more than 12%. Taking into account abovementioned, the presented technique for calculating lock coefficient of differential "Quif" is advisable for practical application.
Corsetti, James A; Green, William E; Ellis, Jonathan D; Schmidt, Greg R; Moore, Duncan T
2016-10-10
Characterizing the thermal properties of optical materials is necessary for understanding how to design an optical system for changing environmental conditions. A method is presented for simultaneously measuring both the linear coefficient of thermal expansion and the temperature-dependent refractive index coefficient of a sample interferometrically in air. Both the design and fabrication of the interferometer is presented as well as a discussion of the results of measuring both a steel and a CaF2 sample.
Relativistic phenomenological equations and transformation laws of relative coefficients
Directory of Open Access Journals (Sweden)
Patrizia Rogolino
2017-06-01
Full Text Available The aim of this paper is to derive the phenomenological equations in the context of special relativistic non-equilibrium thermodynamics with internal variables. In particular, after introducing some results developed in our previous paper, by means of classical non-equilibrium thermodynamic procedure and under suitable assumptions on the entropy density production, the phenomenological equations and transformation laws of phenomenological coefficients are derived. Finally, some symmetries of aforementioned coefficients are obtained.
Determination of ion diffusion coefficients by the electromigration method
International Nuclear Information System (INIS)
Bonchev, G.D.; Milanov, M.V.; Bozhikov, G.A.; Ivanov, P.I.; Priemyshev, A.N.; Maslov, O.D.; Dmitriev, S.N.
2003-01-01
An electrophoretic method for measuring ion diffusion coefficients in aqueous solutions is developed. The value of the diffusion coefficient can be determined from the linear relationship between the square standard deviation of the electrophoretic zone and the time from the start of the diffusion process. Using the device for horizontal zone electrophoresis in a free electrolyte, a series of diffusion experiments are performed with no-carrier-added radionuclides in microconcentrations (10 -9 - 10 -10 M). Diffusion coefficients of 111 In(III), 175 Hf(IV) and 237 Pu(VI) ions at 25 0 C are determined in nitric acid media. Simultaneous determination of the diffusion coefficient and electrophoretic mobility allows one to calculate the effective charge of the investigated ions in accordance with the Nernst-Einstein law
Energy Technology Data Exchange (ETDEWEB)
NONE
1997-01-01
It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.
Apparent Coefficient of Friction of Wheat on Denim.
Schwab, Charles V
2017-07-31
Calculation of the extraction force for a grain entrapment victim requires a coefficient of friction between the grain and the surface of the victim. Because denim is a common fabric for the work clothes that cover entrapment victims, the coefficient of friction between grain and denim becomes necessary. The purpose of this research was to calculate the apparent coefficient of friction of wheat on denim fabric using a proven procedure. The expectation is to improve the current understanding of conditions that influence extraction forces for victims buried in wheat. The apparent coefficient of friction of wheat on denim fabric was calculated to be 0.167 with a standard deviation of ±0.013. The wheat had a moisture content of 10.7% (w.b.) and bulk density of 778.5 kg m-3. The apparent coefficient of friction of wheat on denim was not significantly affected by pull speeds of 0.004, 0.008, and 0.021 mm s-1 nor normal grain pressures of 3.2, 4.8, 6.3, 7.9, and 11.1 kPa. This is a beginning of understanding the conditions that influence the extraction forces for grain entrapment victims. Copyright© by the American Society of Agricultural Engineers.
Diffusion coefficients of tracers in glassy polymer systems prepared by gamma radiolysis
International Nuclear Information System (INIS)
Tonge, M.P.; Gilbert, R.G.
1996-01-01
Diffusion-controlled reactions are common in free radical polymerisation reactions, especially in glassy polymer matrices. Such reactions commonly have an important influence on the polymerisation process and final polymer properties. For example, the dominant growth-stopping event (bimolecular termination) is generally diffusion-controlled. In glassy polymer systems, where molecular mobility is very low, the chain growth mechanism (propagation) may become diffusion-controlled. At present, the mechanism for propagation in glassy polymers is poorly understood, but it is expected by the Smoluchowski expression applied to propagation to depend strongly on the diffusion coefficient of monomer. The objective of this study is to measure reliable diffusion coefficients of small tracer molecules in glassy polymers, and compare these with propagation rate coefficients in similar systems, by the prediction above. Samples were initially prepared in a sealed sampled cell containing monomer, inert diluent, and tracer dye. After irradiation for several days, complete conversion of monomer to polymer can be obtained. The diffusion coefficients for two tracer dyes have been measured as a function of weight fraction polymer glassy poly(methyl methacrylate) samples
Prediction of longitudinal dispersion coefficient using multivariate ...
Indian Academy of Sciences (India)
rivers to continuously monitor river water quality. Unfortunately ... tigators have attempted to implement mathematical methods for ... used in some fields of water resource management ...... Bauwens W 2014 Integrated water quality modelling of.
Path coefficient analysis of zinc dynamics in varying soil environment
International Nuclear Information System (INIS)
Rattan, R.K.; Phung, C.V.; Singhal, S.K.; Deb, D.L.; Singh, A.K.
1994-01-01
Influence of soil properties on labile zinc, as measured by diethylene-triamine pentaacetic acid (DTPA) and zinc-65, and self-diffusion coefficients of zinc was assessed on 22 surface soil samples varying widely in their characteristics following linear regression and path coefficient analysis techniques. DTPA extractable zinc could be predicted from organic carbon status and pH of the soil with a highly significant coefficient of determination (R 2 =0.84 ** ). Ninety seven per cent variation in isotopically exchangeable zinc was explained by pH, clay content and cation exchange capacity (CEC) of soil. The self-diffusion coefficients (DaZn and DpZn) and buffer power of zinc exhibited exponential relationship with soil properties, pH being the most dominant one. Soil properties like organic matter, clay content etc. exhibited indirect effects on zinc diffusion rates via pH only. (author). 13 refs., 6 tabs
Friction coefficients of PTFE bearing liner
Daniels, C. M.
1979-01-01
Data discusses frictional characteristics of PTFE (polytetrafluoroethylene) under temperature extremes and in vacuum environment. Tests were also run on reduced scale hardware to determine effects of vacuum. Data is used as reference by designers of aircraft-control system rod-end bearings and for bearings used in polar regions.
Regularity of the interband light absorption coefficient
Indian Academy of Sciences (India)
Proc. Indian Acad. Sci. (Math. Sci.) Vol. 120, No. 3, June 2010, pp. 351–362. ... 1. Introduction. In the theory of disordered systems, one of the quantities that is ... integrated density of states, whose continuity properties and its behaviour near ...
Modelling of tandem cell temperature coefficients
Energy Technology Data Exchange (ETDEWEB)
Friedman, D.J. [National Renewable Energy Lab., Golden, CO (United States)
1996-05-01
This paper discusses the temperature dependence of the basic solar-cell operating parameters for a GaInP/GaAs series-connected two-terminal tandem cell. The effects of series resistance and of different incident solar spectra are also discussed.
Characterization of the effective electrostriction coefficients in ferroelectric thin films
Kholkin, A. L.; Akdogan, E. K.; Safari, A.; Chauvy, P.-F.; Setter, N.
2001-06-01
Electromechanical properties of a number of ferroelectric films including PbZrxTi1-xO3(PZT), 0.9PbMg1/3Nb2/3O3-0.1PbTiO3(PMN-PT), and SrBi2Ta2O9(SBT) are investigated using laser interferometry combined with conventional dielectric measurements. Effective electrostriction coefficients of the films, Qeff, are determined using a linearized electrostriction equation that couples longitudinal piezoelectric coefficient, d33, with the polarization and dielectric constant. It is shown that, in PZT films, electrostriction coefficients slightly increase with applied electric field, reflecting the weak contribution of non-180° domains to piezoelectric properties. In contrast, in PMN-PT and SBT films electrostriction coefficients are field independent, indicating the intrinsic nature of the piezoelectric response. The experimental values of Qeff are significantly smaller than those of corresponding bulk materials due to substrate clamping and possible size effects. Electrostriction coefficients of PZT layers are shown to depend strongly on the composition and preferred orientation of the grains. In particular, Qeff of (100) textured rhombohedral films (x=0.7) is significantly greater than that of (111) layers. Thus large anisotropy of the electrostrictive coefficients is responsible for recently observed large piezoelectric coefficients of (100) textured PZT films. Effective electrostriction coefficients obtained by laser interferometry allow evaluation of the electromechanical properties of ferroelectric films based solely on the dielectric parameters and thus are very useful in the design and fabrication of microsensors and microactuators.
Realistic absorption coefficient of ultrathin films
International Nuclear Information System (INIS)
Cesaria, M; Caricato, A P; Martino, M
2012-01-01
Both a theoretical algorithm and an experimental procedure are discussed of a new route to determine the absorption/scattering properties of thin films deposited on transparent substrates. Notably, the non-measurable contribution of the film–substrate interface is inherently accounted for. While the experimental procedure exploits only measurable spectra combined according to a very simple algorithm, the theoretical derivation does not require numerical handling of the acquired spectra or any assumption on the film homogeneity and substrate thickness. The film absorption response is estimated by subtracting the measured absorption spectrum of the bare substrate from that of the film on the substrate structure but in a non-straightforward way. In fact, an assumption about the absorption profile of the overall structure is introduced and a corrective factor accounting for the relative film-to-substrate thickness. The method is tested on films of a well known material (ITO) as a function of the film structural quality and influence of the film–substrate interface, both deliberately changed by thickness tuning and doping. Results are found fully consistent with information obtained by standard optical analysis and band gap values reported in the literature. Additionally, comparison with a conventional method demonstrates that our route is generally more accurate even if particularly suited for very thin films. (paper)
Realistic absorption coefficient of ultrathin films
Cesaria, M.; Caricato, A. P.; Martino, M.
2012-10-01
Both a theoretical algorithm and an experimental procedure are discussed of a new route to determine the absorption/scattering properties of thin films deposited on transparent substrates. Notably, the non-measurable contribution of the film-substrate interface is inherently accounted for. While the experimental procedure exploits only measurable spectra combined according to a very simple algorithm, the theoretical derivation does not require numerical handling of the acquired spectra or any assumption on the film homogeneity and substrate thickness. The film absorption response is estimated by subtracting the measured absorption spectrum of the bare substrate from that of the film on the substrate structure but in a non-straightforward way. In fact, an assumption about the absorption profile of the overall structure is introduced and a corrective factor accounting for the relative film-to-substrate thickness. The method is tested on films of a well known material (ITO) as a function of the film structural quality and influence of the film-substrate interface, both deliberately changed by thickness tuning and doping. Results are found fully consistent with information obtained by standard optical analysis and band gap values reported in the literature. Additionally, comparison with a conventional method demonstrates that our route is generally more accurate even if particularly suited for very thin films.
Evaluation of volume compressibility coefficient variations incement ...
African Journals Online (AJOL)
In this study, 2,4,6,8 and 10% of cement at treatment times of 7,14 and 28 days were used to stabilize the bentonite clay. All samples prepared by wet and dry method hadthe same moisture contents in the mentioned levels equal to the liquid limit moisture of the original soil. The studied soil falls in the group CH with the ...
Clustering coefficient and community structure of bipartite networks
Zhang, Peng; Wang, Jinliang; Li, Xiaojia; Li, Menghui; Di, Zengru; Fan, Ying
2008-12-01
Many real-world networks display natural bipartite structure, where the basic cycle is a square. In this paper, with the similar consideration of standard clustering coefficient in binary networks, a definition of the clustering coefficient for bipartite networks based on the fraction of squares is proposed. In order to detect community structures in bipartite networks, two different edge clustering coefficients LC4 and LC3 of bipartite networks are defined, which are based on squares and triples respectively. With the algorithm of cutting the edge with the least clustering coefficient, communities in artificial and real world networks are identified. The results reveal that investigating bipartite networks based on the original structure can show the detailed properties that is helpful to get deep understanding about the networks.
Breakdown coefficients and scaling properties of rain fields
Directory of Open Access Journals (Sweden)
D. Harris
1998-01-01
Full Text Available The theory of scale similarity and breakdown coefficients is applied here to intermittent rainfall data consisting of time series and spatial rain fields. The probability distributions (pdf of the logarithm of the breakdown coefficients are the principal descriptor used. Rain fields are distinguished as being either multiscaling or multiaffine depending on whether the pdfs of breakdown coefficients are scale similar or scale dependent, respectively. Parameter estimation techniques are developed which are applicable to both multiscaling and multiaffine fields. The scale parameter (width, σ, of the pdfs of the log-breakdown coefficients is a measure of the intermittency of a field. For multiaffine fields, this scale parameter is found to increase with scale in a power-law fashion consistent with a bounded-cascade picture of rainfall modelling. The resulting power-law exponent, H, is indicative of the smoothness of the field. Some details of breakdown coefficient analysis are addressed and a theoretical link between this analysis and moment scaling analysis is also presented. Breakdown coefficient properties of cascades are also investigated in the context of parameter estimation for modelling purposes.
measurements of distribution coefficients and lipophilicity values
African Journals Online (AJOL)
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octanol and water, followed by measuring the distribution of the solute in ... Instrumentation and apparatus: HPLC-UV-DAD and HPLC–ESI-MS experiments .... process in the determination of KD and log P values for the HFSLM extracts. ..... Perrin, D.D.; Dempsey, B. Buffers for pH and Metal Ion Control, Chapman and Hall:.
Coefficients of productivity for Yellowstone's grizzly bear habitat
Mattson, David John; Barber, Kim; Maw, Ralene; Renkin, Roy
2004-01-01
This report describes methods for calculating coefficients used to depict habitat productivity for grizzly bears in the Yellowstone ecosystem. Calculations based on these coefficients are used in the Yellowstone Grizzly Bear Cumulative Effects Model to map the distribution of habitat productivity and account for the impacts of human facilities. The coefficients of habitat productivity incorporate detailed information that was collected over a 20-year period (1977-96) on the foraging behavior of Yellowstone's bears and include records of what bears were feeding on, when and where they fed, the extent of that feeding activity, and relative measures of the quantity consumed. The coefficients also incorporate information, collected primarily from 1986 to 1992, on the nutrient content of foods that were consumed, their digestibility, characteristic bite sizes, and the energy required to extract and handle each food. Coefficients were calculated for different time periods and different habitat types, specific to different parts of the Yellowstone ecosystem. Stratifications included four seasons of bear activity (spring, estrus, early hyperphagia, late hyperphagia), years when ungulate carrion and whitebark pine seed crops were abundant versus not, areas adjacent to (bear activity in each region, habitat type, and time period were incorporated into calculations, controlling for the effects of proximity to human facilities. The coefficients described in this report and associated estimates of grizzly bear habitat productivity are unique among many efforts to model the conditions of bear habitat because calculations include information on energetics derived from the observed behavior of radio-marked bears.
Non intrusive measurement of the convective heat transfer coefficient
Energy Technology Data Exchange (ETDEWEB)
Rebay, M.; Mebarki, G.; Padet, J. [Reims Univ., Reims (France). Faculty of Science, GRESPI Thermomechanical Lab; Arfaoui, A. [Reims Univ., Reims (France). Faculty of Science, GRESPI Thermomechanical Lab; Tunis Univ., Tunis (Tunisia). Faculty of Science, EL MANAR, LETTM; Maad, B.R. [Tunis Univ., Tunis (Tunisia). Faculty of Science, EL MANAR, LETTM
2010-07-01
The efficiency of cooling methods in thermal systems such as radiators and heat exchangers must be improved in order to enhance performance. The evaluation of the heat transfer coefficients between a solid and a fluid is necessary for the control and the dimensioning of thermal systems. In this study, the pulsed photothermal method was used to measure the convective heat transfer coefficient on a solid-fluid interface, notably between an air flow and a heated slab mounted on a PVC flat plate. This configuration simulated the electronic air-cooling inside enclosures and racks. The influence of the deflector's inclination angle on the enhancement of heat transfer was investigated using 2 newly developed identification models. The first model was based on a constant heat transfer coefficient during the pulsed experiment, while the second, improved model was based on a variable heat transfer coefficient. The heat transfer coefficient was deduced from the evolution of the transient temperature induced by a sudden deposit of a luminous energy on the front face of the slab. Temperature evolutions were derived by infrared thermography, a camera for cartography and a detector for precise measurement in specific locations. The results show the improvement of measurement accuracies when using a model that considers the temporal evolution of the convective heat transfer coefficient. The deflection of air flow on the upper surface of the heated slab demonstrated better cooling of the slab by the deflection of air flow. 11 refs., 1 tab., 8 figs.
Transport coefficients of black MQGP -branes
Dhuria, Mansi; Misra, Aalok
2015-01-01
The Strominger-Yau-Zaslow (SYZ) mirror, in the `delocalised limit' of Becker et al. (Nucl Phys B 702:207, 2004), of -branes, fractional -branes and flavour -branes wrapping a non-compact four-cycle in the presence of a black hole (BH) resulting in a non-Kähler resolved warped deformed conifold (NKRWDC) in Mia et al. (Nucl Phys B 839:187, 2010), was carried out in Dhuria and Misra (JHEP 1311:001, 2013) and resulted in black -branes. There are two parts in our paper. In the first we show that in the `MQGP' limit discussed in Dhuria and Misra (JHEP 1311:001, 2013) a finite (and hence expected to be more relevant to QGP), finite and very large , and very small , we have the following. (i) The uplift, if valid globally (like Dasgupta et al., Nucl Phys B 755:21, 2006) for fractional branes in conifolds), asymptotically goes to -branes wrapping a two-cycle (homologously a (large) integer sum of two-spheres) in . (ii) Assuming the deformation parameter to be larger than the resolution parameter, by estimating the five structure torsion () classes we verify that in the large- limit, implying the NKRWDC reduces to a warped Kähler deformed conifold. (iii) The local of Dhuria and Misra (JHEP 1311:001, 2013) in the large- limit satisfies the same conditions as the maximal -invariant special Lagrangian three-cycle of of Ionel and Min-OO (J Math 52(3), 2008), partly justifying use of SYZ-mirror symmetry in the `delocalised limit' of Becker et al. (Nucl Phys B 702:207, 2004) in Dhuria and Misra (JHEP 1311:001, 2013). In the second part of the paper, by either integrating out the angular coordinates of the non-compact four-cycle which a -brane wraps around, using the Ouyang embedding, in the DBI action of a -brane evaluated at infinite radial boundary, or by dimensionally reducing the 11-dimensional EH action to five () dimensions and at the infinite radial boundary, we then calculate in particular the (part of the 'MQGP') limit, a variety of gauge and metric
Experimental determination of contraction coefficient and velocity ...
Indian Academy of Sciences (India)
Jailakshmi Menon
2018-04-16
Apr 16, 2018 ... Radial gates are widely used to control the flow in irrigation channels and spillways. Radial gates ... upstream water depth for a vertical sluice gate assuming hydrostatic ... energy loss on the discharge characteristics of vertical.
Comparing coefficients of nested nonlinear probability models
DEFF Research Database (Denmark)
Kohler, Ulrich; Karlson, Kristian Bernt; Holm, Anders
2011-01-01
In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general decomposi......In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general...... decomposition method that is unaffected by the rescaling or attenuation bias that arise in cross-model comparisons in nonlinear models. It recovers the degree to which a control variable, Z, mediates or explains the relationship between X and a latent outcome variable, Y*, underlying the nonlinear probability...
Measurement of conversion coefficients in 208Tl
International Nuclear Information System (INIS)
Wendling, F.
1976-06-01
A electron spectrometer composed by a Li drifted Si detector and a uniform magnetic field was constructed. The magnetic field is used to focus the electrons on the detector and to filter the other radiations. After the construction the instrument was calibrated in absolute eficience and was used together with a Ge(Li) spectrometer also calibrated, in the measurement of internal conversion coeficients of the 433 and 453 keV transitions in 208 Tl [pt
The assessment of voce coefficient for WWR-c reactor
International Nuclear Information System (INIS)
Kochnov, O.Yu.; Rybkin, N.I.
2006-01-01
The air cavity effect in WWR-ts reactor core on the total reactivity is analyzed. The experimental data of void coefficient depending on the air cavity position inside the reactor core are obtained [ru
Analytical computation of reflection and transmission coefficients for love waves
International Nuclear Information System (INIS)
Romanelli, F.; Vaccari, F.
1995-09-01
The computation of the transmission and reflection coefficients is an important step in the construction, if modal summation technique is used, of synthetic seismograms for 2-D or 3-D media. These coupling coefficients for Love waves at a vertical discontinuity are computed analytically. Numerical test for realistic structures show how the energy carried by an incoming mode is redistributed on the various modes existing on both sides of the vertical interface. (author). 15 refs, 8 figs
Solutions of the spin coefficient equations with nongeodesic eigenrays
International Nuclear Information System (INIS)
Kota, J.; Lukacs, B.; Perjes, Z.
1982-01-01
Among the many significant results obtained by spin coefficient techniques in general relativity, the exact integrals of gravitational equations have enjoyed particular attention. These integration procedures were first carried out with respect to a congruence of null geodesic curves. The authors show that spin coefficient equations can sometimes be exactly solved when the selected null congruence is nongeodesic. They derive metrics with this property and, among them, a new solution of the coupled Einstein-Maxwell equations. (Auth.)
Czech Academy of Sciences Publication Activity Database
Mukhamedzhanov, A. M.; Azhari, A.; Burjan, Václav; Gagliardi, C. A.; Kroha, Václav; Sattarov, A.; Tang, X.; Trache, L.; Tribble, R. E.
2003-01-01
Roč. 725, č. 725 (2003), s. 279-294 ISSN 0375-9474 R&D Projects: GA ČR GA202/01/0709; GA MŠk ME 385 Institutional research plan: CEZ:AV0Z1048901 Keywords : radiative capture reaction * asymptotic normalization coefficient Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.761, year: 2003
Czech Academy of Sciences Publication Activity Database
Mukhamedzhanov, A. M.; Azhari, A.; Burjan, Václav; Gagliardi, C. A.; Kroha, Václav; Sattarov, A.; Tang, X.; Trache, L.; Tribble, R. E.
2003-01-01
Roč. 725, č. 22 (2003), s. 279-294 ISSN 0375-9474 R&D Projects: GA ČR GA202/01/0709; GA MŠk ME 385 Institutional research plan: CEZ:AV0Z1048901 Keywords : radiative capture reaction * asymptotic normalization coefficient Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.761, year: 2003
Effect of Variable Manning Coefficients on Tsunami Inundation
Barberopoulou, A.; Rees, D.
2017-12-01
Numerical simulations are commonly used to help estimate tsunami hazard, improve evacuation plans, issue or cancel tsunami warnings, inform forecasting and hazard assessments and have therefore become an integral part of hazard mitigation among the tsunami community. Many numerical codes exist for simulating tsunamis, most of which have undergone extensive benchmarking and testing. Tsunami hazard or risk assessments employ these codes following a deterministic or probabilistic approach. Depending on the scope these studies may or may not consider uncertainty in the numerical simulations, the effects of tides, variable friction or estimate financial losses, none of which are necessarily trivial. Distributed manning coefficients, the roughness coefficients used in hydraulic modeling, are commonly used in simulating both riverine and pluvial flood events however, their use in tsunami hazard assessments is primarily part of limited scope studies and for the most part, not a standard practice. For this work, we investigate variations in manning coefficients and their effects on tsunami inundation extent, pattern and financial loss. To assign manning coefficients we use land use maps that come from the New Zealand Land Cover Database (LCDB) and more recent data from the Ministry of the Environment. More than 40 classes covering different types of land use are combined into major classes such as cropland, grassland and wetland representing common types of land use in New Zealand, each of which is assigned a unique manning coefficient. By utilizing different data sources for variable manning coefficients, we examine the impact of data sources and classification methodology on the accuracy of model outputs.
Measurement of reactivity coefficients for code validation
International Nuclear Information System (INIS)
Nuding, Matthias; Loetsch, Thomas
2005-01-01
In the year 2003 measurements in the cold reactor state have been performed at the NPP KKI 2 in order to validate the codes that are used for reactor core calculations and especially for the proof of the shutdown margin that is produced by calculations only. For full power states code verification is quite easy because the calculations can be compared with different measured values, e.g. with the activation values determined by the aeroball system. For cold reactor states, however the data base is smaller, especially for reactor cores that are quite 'inhomogeneous' and have rather high Pu-fiss-and 235 U-contents. At the same time the cold reactor state is important regarding the shutdown margin. For these reasons the measurements mentioned above have been performed in order to check the accuracy of the codes that are used by the operator and by our organization for many years. Basically, boron concentrations and control rod worths for different configurations have been measured. The results of the calculation show a very good agreement with the measured values. Therefore, it can be stated that the operator's as well as our code system is suitable for routine use, e.g. during licensing procedures (Authors)
Riesz Frames and Approximation of the Frame Coefficients
DEFF Research Database (Denmark)
Christensen, Ole
1996-01-01
A frame is a familyof elements in a Hilbert space with the propertythat every element in the Hilbert space can be written as a (infinite)linear combination of the frame elements. Frame theory describes howone can choose the corresponding coefficients, which are calledframe coefficients. From...... the mathematical point of view this isgratifying, but for applications it is a problem that the calculationrequires inversion of an operator on the Hilbert space.The projection method is introduced in order to avoid this problem.The basic idea is to consider finite subfamiliesof the frame and the orthogonal...... projection onto its span. Forfin QTR H,P_nf has a representation as a linear combinationof f_i,i=1,2,..,n, and the corresponding coefficients can be calculatedusing finite dimensional methods. We find conditions implying that thosecoefficients converge to the correct frame coefficients as n goes...
Kinetic coefficients for the biological treatment of tannery wastewater
International Nuclear Information System (INIS)
Haydar, S.
2008-01-01
Determination of kinetic coefficients for a particular wastewater is imperative for the rational design of biological treatment-facilities. The present study was undertaken with the objective of finding out kinetic coefficients for tannery wastewater. A bench-scale model of aerated lagoon, consisting of an aeration tank and final clarifier, was use to conduct the studies. The model was operated continuously for 96 days, by varying the detention times from 3 to 9 days. Influent for the aerated lagoon was settled tannery wastewater. Biochemical oxygen demand (BOD) of the influent and effluent and the mixed-liquor suspended solids (MLSS) of aeration tank were determined at various detention-times so as to generate data for kinetic coefficients. The kinetic coefficients k, Ks, Y and Ed were found to be 3.125 day/sup -1/, 488 mg/L, 0.64 and 0.035 day/sup -1/ respectively. Overall rate-constant of BOD, removal 'K' was also determined and was found to be 1.43 day/sup -1/. Kinetic coefficients were determined, at mean reactor-temperature of 30.2 degree C. These coefficients may be utilized for the design of biological-treatment facilities for tannery wastewater. (author)
Towards a nonperturbative calculation of weak Hamiltonian Wilson coefficients
Bruno, Mattia; Lehner, Christoph; Soni, Amarjit; Rbc; Ukqcd Collaborations
2018-04-01
We propose a method to compute the Wilson coefficients of the weak effective Hamiltonian to all orders in the strong coupling constant using Lattice QCD simulations. We perform our calculations adopting an unphysically light weak boson mass of around 2 GeV. We demonstrate that systematic errors for the Wilson coefficients C1 and C2 , related to the current-current four-quark operators, can be controlled and present a path towards precise determinations in subsequent works.
Limits of the memory coefficient in measuring correlated bursts
Jo, Hang-Hyun; Hiraoka, Takayuki
2018-03-01
Temporal inhomogeneities in event sequences of natural and social phenomena have been characterized in terms of interevent times and correlations between interevent times. The inhomogeneities of interevent times have been extensively studied, while the correlations between interevent times, often called correlated bursts, are far from being fully understood. For measuring the correlated bursts, two relevant approaches were suggested, i.e., memory coefficient and burst size distribution. Here a burst size denotes the number of events in a bursty train detected for a given time window. Empirical analyses have revealed that the larger memory coefficient tends to be associated with the heavier tail of the burst size distribution. In particular, empirical findings in human activities appear inconsistent, such that the memory coefficient is close to 0, while burst size distributions follow a power law. In order to comprehend these observations, by assuming the conditional independence between consecutive interevent times, we derive the analytical form of the memory coefficient as a function of parameters describing interevent time and burst size distributions. Our analytical result can explain the general tendency of the larger memory coefficient being associated with the heavier tail of burst size distribution. We also find that the apparently inconsistent observations in human activities are compatible with each other, indicating that the memory coefficient has limits to measure the correlated bursts.
International Nuclear Information System (INIS)
Sakamoto, Yoshiaki; Takebe, Shinichi; Ogawa, Hiromichi; Inagawa, Satoshi; Sasaki, Tomozou
2001-01-01
In order to study sorption behavior of U series radionuclides (Pb, Ra, Th, Ac, Pa and U) under aerated zone environment (loam-rain water system) and aquifer environment (sand-groundwater system) for safety assessment of U bearing waste, pH dependence of distribution coefficients of each element has been obtained. The pH dependence of distribution coefficients of Pb, Ra, Th, Ac and U was analyzed by model calculation based on aqueous speciation of each element and soil surface charge characteristics, which is composed of a cation exchange capacity and surface hydroxyl groups. From the model calculation, the sorption behavior of Pb, Ra, Th, Ac and U could be described by a combination of cation exchange reaction and surface-complexation model. (author)
Measurement of Dynamic Friction Coefficient on the Irregular Free Surface
International Nuclear Information System (INIS)
Yeom, S. H.; Seo, K. S.; Lee, J. H.; Lee, K. H.
2007-01-01
A spent fuel storage cask must be estimated for a structural integrity when an earthquake occurs because it freely stands on ground surface without a restriction condition. Usually the integrity estimation for a seismic load is performed by a FEM analysis, the friction coefficient for a standing surface is an important parameter in seismic analysis when a sliding happens. When a storage cask is placed on an irregular ground surface, measuring a friction coefficient of an irregular surface is very difficult because the friction coefficient is affected by the surface condition. In this research, dynamic friction coefficients on the irregular surfaces between a concrete cylinder block and a flat concrete slab are measured with two methods by one direction actuator
Investigation on Thrust and Moment Coefficients of a Centrifugal Turbomachine
Directory of Open Access Journals (Sweden)
Bo Hu
2018-04-01
Full Text Available In radial pumps and turbines, the centrifugal through-flow in both the front and the back chambers is quite common. It strongly impacts the core swirl ratio, pressure distribution, axial thrust and frictional torque. In order to investigate these relationships experimentally, a test rig was designed at the University of Duisburg-Essen and described in this paper. Based on both the experimental and numerical results, correlations are determined to predict the impacts of the centrifugal through-flow on the core swirl ratio, the thrust coefficient and the moment coefficient. Two correlations respectively are determined to associate the core swirl ratio with the local through-flow coefficient for both Batchelor type flow and Stewartson type flow. The correlations describing the thrust coefficient and the moment coefficient in a rotor-stator cavity with centripetal through-flow (Hu et al., 2017 are modified for the case of centrifugal through-flow. The Daily and Nece diagram distinguishing between different flow regimes in rotor-stator cavities is extended with a through-flow coordinate into 3D. The achieved results provide a comprehensive data base which is intended to support the calculation of axial thrust and moment coefficients during the design process of radial pumps and turbines in a more accurate manner.
Numerical study of effects of accommodation coefficients on slip phenomena
Energy Technology Data Exchange (ETDEWEB)
Choi, Young Jae; Kwon, Oh Joon [KAIST, Daejeon (Korea, Republic of)
2015-05-15
An unstructured mesh Navier-Stokes solver employing a Maxwell slip boundary condition was developed. The present flow solver was applied to the simulation of flows around an axisymmetric hollow cylinder in a Mach 10.4 free stream, known as Calspan-UB Research Center (CUBRC) Run 14 case, and the velocity slip and the temperature jump on the cylinder surface were investigated. The effect of tangential momentum and thermal accommodation coefficients used in the Maxwell condition was also investigated by adjusting their values. The results show that the reverse flow region is developed on the body surface due to the interaction between the shock and the boundary layer. Also, the shock impingement makes pressure high. The flow properties on the surface agree well with the experimental data, and the velocity slip and the temperature jump vary consistently with the local Knudsen number change. The accommodation coefficients affect the slip phenomena and the size of the flow region. The slip phenomena become larger when both tangential momentum and thermal accommodation coefficients are decreased. However, the range of the reverse flow region decreases when the momentum accommodation coefficient is decreased. The characteristics of the momentum and thermal accommodation coefficients also are overlapped when they are altered together.
Diffusion coefficients of decay products of radon and thoron
International Nuclear Information System (INIS)
Raghunath, B.; Kotrappa, P.
1979-01-01
The diffusion coefficients of the decay products of radon and thoron have relevance in the evaluation of inhalation hazards in uranium and thorium processing industries. A recently developed diffusion sampler, based on Mercer's theory of diffusional deposition between the concentric circular plates, has been used for determining the diffusion coefficients of the unattached decay products of radon and thoron (RaA, RaB, RaC and ThB). Experiments were conducted at different ventilation rates (6 and 60 changes/hr) at different relative humidities (10 and 90%) and both in air and argon atmospheres. Diffusion coefficients were found to increase with increasing ventilation rates and were found to decrease at higher relative humidities, the effect being more marked at lower ventilation rates. Both of these effects were less pronounced in argon than in air. Results are discussed in light of the known properties of these decay products. (author)
Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel
Directory of Open Access Journals (Sweden)
S. Ilaiyavel
2013-03-01
Full Text Available In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear loss and wear coefficient were evaluated through pin on disc test using a sliding velocity of 3.0 m/s under normal load of 40 N and controlled condition of temperature and humidity. Based on the results of the wear test, the Heat treated Manganese Phosphate with oil lubricant exhibited the lowest average wear coefficient and the lowest wear loss under 40 N load.
Schwenke, David W.; Jaffe, Richard L.; Chaban, Galina M.
2016-01-01
We have generated accurate global potential energy surfaces for CO+Ar and CO+O that correlate with atom-diatom pairs in their ground electronic states based on extensive ab initio electronic structure calculations and used these potentials in quasi-classical trajectory nuclear dynamics calculations to predict the thermal dissociation rate coefficients over 5000- 35000 K. Our results are not compatible with the 20-45 year old experimental results. For CO + Ar we obtain fairly good agreement with the experimental rate coefficients of Appleton et al. (1970) and Mick and Roth (1993), but our computed rate coefficients exhibit a stronger temperature dependence. For CO + O our dissociation rate coefficient is in close agreement with the value from the Park model, which is an empirical adjustment of older experimental results. However, we find the rate coefficient for CO + O is only 1.5 to 3.3 times larger than CO + Ar over the temperature range of the shock tube experiments (8000-15,000 K). The previously accepted value for this rate coefficient ratio is 15, independent of temperature. We also computed the rate coefficient for the CO + O ex- change reaction which forms C + O2. We find this reaction is much faster than previously believed and is the dominant process in the removal of CO at temperatures up to 16,000 K. As a result, the dissociation of CO is accomplished in two steps (react to form C+O2 and then O2 dissociates) that are endothermic by 6.1 and 5.1 eV, instead of one step that requires 11.2 eV to break the CO bond.
Broadband computation of the scattering coefficients of infinite arbitrary cylinders.
Blanchard, Cédric; Guizal, Brahim; Felbacq, Didier
2012-07-01
We employ a time-domain method to compute the near field on a contour enclosing infinitely long cylinders of arbitrary cross section and constitution. We therefore recover the cylindrical Hankel coefficients of the expansion of the field outside the circumscribed circle of the structure. The recovered coefficients enable the wideband analysis of complex systems, e.g., the determination of the radar cross section becomes straightforward. The prescription for constructing such a numerical tool is provided in great detail. The method is validated by computing the scattering coefficients for a homogeneous circular cylinder illuminated by a plane wave, a problem for which an analytical solution exists. Finally, some radiation properties of an optical antenna are examined by employing the proposed technique.
Energy distribution for Coefficients of Redundant Signal Representations of Music
DEFF Research Database (Denmark)
Endelt, Line Ørtoft; la Cour-Harbo, Anders
2005-01-01
different time-frequency dictionaries. We have applied these methods to music to examine their ability to express music signals in a sparse manner for a number of dictionaries and window lengths. The evaluation is based on the m-term approximation needed to represent 90 %, 95 %, 99 % and 99......In this paper we investigate how the energy is distributed in the coefficients vector of various redundant signal representations of music signals. The representations are found using Basis Pursuit, Matching Pursuit, Alternating Projections, Best Orthogonal Basis and Method of Frames, with five.......9 % of the energy in the coefficients, also the time consummation for finding the representations are considered. The distribution of energy in the coefficients of the representations found using Basis Pursuit, Matching Pursuit, Alternating Projections and Best Orthogonal Basis depends mainly on the signal...
The coefficient of friction in Parkinson's disease gait.
Kleiner, Ana; Galli, M; Franceschini, M; De Pandis, M F; Stocchi, F; Albertini, G; de Barros, Ricardo Machado Leite
This study aimed to characterize the coefficient of friction (COF) curves of patients with Parkinson's disease (PD) during barefoot gait and to evaluate the relationships between this variable and functional scales. Twenty-two subjects with PD (ON phase of levodopa) and 22 healthy subjects participated in this study. The participants walked barefoot along a pathway that went over two force plates embedded in the floor of the data collection room. The instantaneous COF was calculated as the ratio between the horizontal and vertical components of the ground reaction forces. Two-sample t-tests applied to every 1% of the support phase of the COF curve were used to compare the groups and to identify the phases in which the two groups were different. Specifically, three COF areas were computed: Area 1 (for the loading response phase), Area 2 (for the midstance phase) and Area 3 (for the terminal stance phase). Pearson's tests were applied to assess the associations between the COF curve areas and the clinical scales. The subjects with PD exhibited lower COF values during the loading response and terminal stance phases and higher COF values during the mid-stance phase compared with the control group. A strong positive correlation was observed between Area 1 and the Timed Up and Go Test (90.3%). In conclusion, the patients' COFs exhibited patterns that were different from those of the control group. Moreover, during the loading response phase, these differences were well-correlated with the Timed Up and Go Test scale data; Timed Up and Go Test data can be used to identify the risk of falls among PD patients.
Vapor Pressure and Evaporation Coefficient of Silicon Monoxide over a Mixture of Silicon and Silica
Ferguson, Frank T.; Nuth, Joseph A., III
2012-01-01
The evaporation coefficient and equilibrium vapor pressure of silicon monoxide over a mixture of silicon and vitreous silica have been studied over the temperature range (1433 to 1608) K. The evaporation coefficient for this temperature range was (0.007 plus or minus 0.002) and is approximately an order of magnitude lower than the evaporation coefficient over amorphous silicon monoxide powder and in general agreement with previous measurements of this quantity. The enthalpy of reaction at 298.15 K for this reaction was calculated via second and third law analyses as (355 plus or minus 25) kJ per mol and (363.6 plus or minus 4.1) kJ per mol respectively. In comparison with previous work with the evaporation of amorphous silicon monoxide powder as well as other experimental measurements of the vapor pressure of silicon monoxide gas over mixtures of silicon and silica, these systems all tend to give similar equilibrium vapor pressures when the evaporation coefficient is correctly taken into account. This provides further evidence that amorphous silicon monoxide is an intimate mixture of small domains of silicon and silica and not strictly a true compound.
Measurement and analysis of reactivity temperature coefficient of CEFR
International Nuclear Information System (INIS)
Chen Yiyu; Hu Yun; Yang Xiaoyan; Fan Zhendong; Zhang Qiang; Zhao Jinkun; Li Zehua
2013-01-01
The reactivity temperature coefficient of CEFR was calculated by CITATION program and compared with the results calculated by correlative programs and measured from experiments for temperature effects. It is indicated that the calculation results from CITATION agree well with measured values. The reactivity temperature coefficient of CEFR is about -4 pcm/℃. The deviation of the measured values between the temperature increasing and decreasing processes is about 11%, which satisfies the experiment acceptance criteria. The measured results can validate the calculation ones by program and can provide important reference data for the safety operation of CEFR and the analysis of the reactivity balance in the reactor refueling situation. (authors)
Directory of Open Access Journals (Sweden)
Qieni Lu
2015-08-01
Full Text Available We measure temperature dependence on Kerr coefficient and quadratic polarized optical coefficient of a paraelectric Mn:Fe:KTN crystal simultaneously in this work, based on digital holographic interferometry (DHI. And the spatial distribution of the field-induced refractive index change can also be visualized and estimated by numerically retrieving sequential phase maps of Mn:Fe:KTN crystal from recording digital holograms in different states. The refractive indices decrease with increasing temperature and quadratic polarized optical coefficient is insensitive to temperature. The experimental results suggest that the DHI method presented here is highly applicable in both visualizing the temporal and spatial behavior of the internal electric field and accurately measuring electro-optic coefficient for electrooptical media.
Ponterotto, Joseph G; Ruckdeschel, Daniel E
2007-12-01
The present article addresses issues in reliability assessment that are often neglected in psychological research such as acceptable levels of internal consistency for research purposes, factors affecting the magnitude of coefficient alpha (alpha), and considerations for interpreting alpha within the research context. A new reliability matrix anchored in classical test theory is introduced to help researchers judge adequacy of internal consistency coefficients with research measures. Guidelines and cautions in applying the matrix are provided.
Development of reflectance-based crop coefficients for corn
International Nuclear Information System (INIS)
Neale, C.M.U.; Bausch, W.C.; Heermann, D.F.
1989-01-01
Concurrent measurements of reflected canopy radiation and the basal crop coefficient (K^b) for corn were conducted throughout a season in order to develop a reflectance-based crop coefficient model. Reflectance was measured in Landsat Thematic Mapper bands TM3 (0.63 - 0.69 um) and TM4 (0.76 - 0.90 um) and used in the calculation of a vegetation index called the normalized difference (ND). A linear transformation of the ND was used as the reflectance-based crop coefficient (Kcr). The transformation equates the ND for dry bare soil and the ND at effective cover, to the basal crop coefficient for dry soil evaporation and at effective cover, respectively. Basal crop coefficient values for com were obtained from daily evapotranspiration measurements of corn and alfalfa, using hydraulic weighing lysimeters. The Richards growth curve function was fitted to both sets of data. The K^b values were determined to be within -2.6% and 4.7% of the K^^ values. The date of effective cover obtained from the K^b data was within four days of the date on which the ND curve reached its maxima according to the Richards function. A comparison of the Kcr with basal crop curves from the literature for several years of data indicated good agreement. Reflectance-based crop coefficients are sensitive to periods of slow and fast growth induced by weather conditions, resulting in a real time coefficient, independent from the traditional time base parameters based on the day of planting and effective cover
Derivation of the chemical-equilibrium rate coefficient using scattering theory
Mickens, R. E.
1977-01-01
Scattering theory is applied to derive the equilibrium rate coefficient for a general homogeneous chemical reaction involving ideal gases. The reaction rate is expressed in terms of the product of a number of normalized momentum distribution functions, the product of the number of molecules with a given internal energy state, and the spin-averaged T-matrix elements. An expression for momentum distribution at equilibrium for an arbitrary molecule is presented, and the number of molecules with a given internal-energy state is represented by an expression which includes the partition function.
Chondroitin sulfate reduces the friction coefficient of articular cartilage.
Basalo, Ines M; Chahine, Nadeen O; Kaplun, Michael; Chen, Faye H; Hung, Clark T; Ateshian, Gerard A
2007-01-01
The objective of this study was to investigate the effect of chondroitin sulfate (CS)-C on the frictional response of bovine articular cartilage. The main hypothesis is that CS decreases the friction coefficient of articular cartilage. Corollary hypotheses are that viscosity and osmotic pressure are not the mechanisms that mediate the reduction in the friction coefficient by CS. In Experiment 1, bovine articular cartilage samples (n=29) were tested in either phosphate buffered saline (PBS) or in PBS containing 100mg/ml of CS following 48h incubation in PBS or in PBS+100mg/ml CS (control specimens were not subjected to any incubation). In Experiment 2, samples (n=23) were tested in four different solutions: PBS, PBS+100mg/ml CS, and PBS+polyethylene glycol (PEG) (133 or 170mg/ml). In Experiment 3, samples (n=18) were tested in three solutions of CS (0, 10 and 100mg/ml). Frictional tests (cartilage-on-glass) were performed under constant stress (0.5MPa) for 3600s and the time-dependent friction coefficient was measured. Samples incubated or tested in a 100mg/ml CS solution exhibited a significantly lower equilibrium friction coefficient than the respective PBS control. PEG solutions delayed the rise in the friction coefficient relative to the PBS control, but did not reduce the equilibrium value. Testing in PBS+10mg/ml of CS did not cause any significant decrease in the friction coefficient. In conclusion, CS at a concentration of 100mg/ml significantly reduces the friction coefficient of bovine articular cartilage and this mechanism is neither mediated by viscosity nor osmolarity. These results suggest that direct injection of CS into the joint may provide beneficial tribological effects.
Measurement of linear attenuation coefficient of different materials
International Nuclear Information System (INIS)
Ali, M. M.
2013-07-01
In this research we study the linear attenuation coefficient from the materials concrete, brick, mixture concrete and iron. In the secondary standard dosimetry laboratory in Atomic Energy from different distance by use Cs-137 sours, chamber farmer 2675 A-600 cc-S/N 0511, and electrometer 2670 A-S/N 114. Found the value of linear attenuation coefficient of concert in the range 0.167 cm -1 , the brick in the range 0.063 -1 and mixture concrete and iron in the range 0.253cm -1 .(Author)
Temperature coefficients of reactivity in the fourth loading of ZENITH
International Nuclear Information System (INIS)
Caro Manso, R.; Freemantle, R.G.; Rogers, J.D.
1962-10-01
Measurements have been made of the temperature coefficients of reactivity associated with the core plus end reflectors and the side reflector of the fourth core loading of ZENITH, which had a carbon/U235 atomic ratio of 7788 and no other absorber. (author)
Temperature coefficients of reactivity in the fourth loading of ZENITH
Energy Technology Data Exchange (ETDEWEB)
Caro Manso, R; Freemantle, R G; Rogers, J D [Graphite Reactor Physics Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)
1962-10-15
Measurements have been made of the temperature coefficients of reactivity associated with the core plus end reflectors and the side reflector of the fourth core loading of ZENITH, which had a carbon/U235 atomic ratio of 7788 and no other absorber. (author)
International Nuclear Information System (INIS)
Castro-Palacio, Juan Carlos; Bemish, Raymond J.; Meuwly, Markus
2015-01-01
The O( 3 P) + NO( 2 Π) → O 2 (X 3 Σ g − ) + N( 4 S) reaction is among the N- and O- involving reactions that dominate the energetics of the reactive air flow around spacecraft during hypersonic atmospheric re-entry. In this regime, the temperature in the bow shock typically ranges from 1000 to 20 000 K. The forward and reverse rate coefficients for this reaction derived directly from trajectory calculations over this range of temperature are reported in this letter. Results compare well with the established equilibrium constants for the same reaction from thermodynamic quantities derived from spectroscopy in the gas phase which paves the way for large-scale in silico investigations of equilibrium rates under extreme conditions
Castro-Palacio, Juan Carlos; Bemish, Raymond J; Meuwly, Markus
2015-03-07
The O((3)P) + NO((2)Π) → O2(X(3)Σg(-)) + N((4)S) reaction is among the N- and O- involving reactions that dominate the energetics of the reactive air flow around spacecraft during hypersonic atmospheric re-entry. In this regime, the temperature in the bow shock typically ranges from 1000 to 20,000 K. The forward and reverse rate coefficients for this reaction derived directly from trajectory calculations over this range of temperature are reported in this letter. Results compare well with the established equilibrium constants for the same reaction from thermodynamic quantities derived from spectroscopy in the gas phase which paves the way for large-scale in silico investigations of equilibrium rates under extreme conditions.
Condensation coefficient of water in a weak condensation state
International Nuclear Information System (INIS)
Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo
2008-01-01
The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].
Condensation coefficient of water in a weak condensation state
Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo
2008-07-01
The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].
Transformation formulas for legendre coefficients of double-differential cross sections
International Nuclear Information System (INIS)
Shi Xiangjun; Zhang Jingshang
1989-01-01
Approximate analytical formulas have been derived for the transformation of Legendre coefficients of double-differential continuum cross sections of two-body nuclear reactions from the center-of-mass to the laboratory system. This transformation differs from that of elastic-scattering angular distribution coefficients on its accuracy which depends not only upon the target mass, but also upon outgoing energies. A fast code has been written to transform Legendre coefficients of neutron inelastic scattering cross-sections. The calculations have been carried out using a recently introduced numerical integration method for more complicated problems in which the energy spectrum is either an evaporation spectrum or a spectrum obtained from a (pre-)compound model. The results are quite satisfactory provided that the target mass or the outgoing energy is not sufficiently low
The adsorption coefficient (KOC) of chlorpyrifos in clay soil
International Nuclear Information System (INIS)
Halimah Muhamad; Nashriyah Mat; Tan Yew Ai; Ismail Sahid
2005-01-01
The purpose of this study was to determine the adsorption coefficient (KOC) of chlorpyrifos in clay soil by measuring the Freundlich adsorption coefficient (Kads(f)) and desorption coefficient (1/n value) of chlorpyrifos. It was found that the Freundlich adsorption coefficient (Kads(f)) and the linear regression (r2) of the Freundlich adsorption isotherm for chlorpyrifos in the clay soil were 52.6 L/kg and 0.5244, respectively. Adsorption equilibrium time was achieved within 24 hours for clay soil. This adsorption equilibrium time was used to determine the effect of concentration on adsorption. The adsorption coefficient (KOC) of clay soil was found to be 2783 L/kg with an initial concentration solution of 1 μg/g, soil-solution ratio (1:5) at 300 C when the equilibrium between the soil matrix and solution was 24 hours. The Kdes decreased over four repetitions of the desorption process. The chlorpyrifos residues may be strongly adsorbed onto the surface of clay. (Author)
Statistical Study of Turbulence: Spectral Functions and Correlation Coefficients
Frenkiel, Francois N.
1958-01-01
In reading the publications on turbulence of different authors, one often runs the risk of confusing the various correlation coefficients and turbulence spectra. We have made a point of defining, by appropriate concepts, the differences which exist between these functions. Besides, we introduce in the symbols a few new characteristics of turbulence. In the first chapter, we study some relations between the correlation coefficients and the different turbulence spectra. Certain relations are given by means of demonstrations which could be called intuitive rather than mathematical. In this way we demonstrate that the correlation coefficients between the simultaneous turbulent velocities at two points are identical, whether studied in Lagrange's or in Euler's systems. We then consider new spectra of turbulence, obtained by study of the simultaneous velocities along a straight line of given direction. We determine some relations between these spectra and the correlation coefficients. Examining the relation between the spectrum of the turbulence measured at a fixed point and the longitudinal-correlation curve given by G. I. Taylor, we find that this equation is exact only when the coefficient is very small.
Determination of sedimentation rates and absorption coefficient of ...
African Journals Online (AJOL)
DR. MIKE HORSFALL
particles have pores that can absorb radiation. Gamma rays have been used to study the absorption coefficients of cobalt(II) insoluble compounds (Essien and Ekpe, 1998), densities of marine sediments. (Gerland and Villinger, 1995) and soil particle-size distribution (Vaz et al., 1992). In this study, sedimentation rates of ...
Determination of the Drag Resistance Coefficients of Different Vehicles
Fahsl, Christoph; Vogt, Patrik
2018-01-01
While it has been demonstrated how air resistance could be analyzed by using mobile devices, this paper demonstrates a method of how to determine the drag resistance coefficient "c" of a commercial automobile by using the acceleration sensor of a smartphone or tablet. In an academic context, the drag resistance is often mentioned, but…
Research Note On New Limits of the Coefficient of Gravitation ...
Indian Academy of Sciences (India)
Research Note. On New Limits of the Coefficient of Gravitation Shielding. Michele Caputo. Physics Department, University La Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy. and. Department of Geology and Geophysics, Texas A&M University, College Station TX, 77843,. USA. e-mail: mcaputo@g24ux.phys.uniroma1.it.
The influence of hydrogen bonding on partition coefficients
Borges, Nádia Melo; Kenny, Peter W.; Montanari, Carlos A.; Prokopczyk, Igor M.; Ribeiro, Jean F. R.; Rocha, Josmar R.; Sartori, Geraldo Rodrigues
2017-02-01
This Perspective explores how consideration of hydrogen bonding can be used to both predict and better understand partition coefficients. It is shown how polarity of both compounds and substructures can be estimated from measured alkane/water partition coefficients. When polarity is defined in this manner, hydrogen bond donors are typically less polar than hydrogen bond acceptors. Analysis of alkane/water partition coefficients in conjunction with molecular electrostatic potential calculations suggests that aromatic chloro substituents may be less lipophilic than is generally believed and that some of the effect of chloro-substitution stems from making the aromatic π-cloud less available to hydrogen bond donors. Relationships between polarity and calculated hydrogen bond basicity are derived for aromatic nitrogen and carbonyl oxygen. Aligned hydrogen bond acceptors appear to present special challenges for prediction of alkane/water partition coefficients and this may reflect `frustration' of solvation resulting from overlapping hydration spheres. It is also shown how calculated hydrogen bond basicity can be used to model the effect of aromatic aza-substitution on octanol/water partition coefficients.
Calculation of the mass transfer coefficient for the combustion of a carbon particle
Energy Technology Data Exchange (ETDEWEB)
Scala, Fabrizio [Istituto di Ricerche sulla Combustione - CNR, P.le Tecchio 80, 80125 Napoli (Italy)
2010-01-15
In this paper we address the calculation of the mass transfer coefficient around a burning carbon particle in an atmosphere of O{sub 2}, N{sub 2}, CO{sub 2}, CO, and H{sub 2}O. The complete set of Stefan-Maxwell equations is analytically solved under the assumption of no homogeneous reaction in the boundary layer. An expression linking the oxygen concentration and the oxygen flux at the particle surface (as a function of the bulk gas composition) is derived which can be used to calculate the mass transfer coefficient. A very simple approximate explicit expression is also given for the mass transfer coefficient, that is shown to be valid in the low oxygen flux limit or when the primary combustion product is CO{sub 2}. The results are given in terms of a correction factor to the equimolar counter-diffusion mass transfer coefficient, which is typically available in the literature for specific geometries and/or fluid-dynamic conditions. The significance of the correction factor and the accuracy of the different available expressions is illustrated for several cases of practical interest. Results show that under typical combustion conditions the use of the equimolar counter-diffusion mass transfer coefficient can lead to errors up to 10%. Larger errors are possible in oxygen-enriched conditions, while the error is generally low in oxy-combustion. (author)
THE DETERMINATION OF DIFFUSION COEFFICIENT OF INVERT MATERIALS
International Nuclear Information System (INIS)
P. Heller and J. Wright
2000-01-01
The Engineered Barrier System (EBS) Testing Department is performing tests in the Department of Energy's Atlas Facility to evaluate the performance of various means for increasing the time for breakthrough of radionuclides from the waste package to the base of the invert. This includes testing various barriers in the invert as a means of increasing breakthrough time through the process of diffusion. A diffusion barrier may serve as an invert material for the emplacement drifts. The invert material may consist of crushed tuff from the repository excavation at Yucca Mountain or silica sand. The objective of this report is to determine the diffusion coefficient of the crushed tuff and silica sand invert materials specified by the EBS Testing Department. The laboratory derived information from the testing was used in the Nernst-Einstein equation (Jurinak et al. 1987, p. 626) to determine the diffusion coefficient of the invert material. This report transmits the results and describes the methodology and interpretation. The scope of this report is to determine the diffusion coefficients of the invert materials mentioned above using the centrifuge at UFA Ventures. Standard laboratory procedures, described in Section 2 of this report, were used. The diffusion coefficients are to be determined over a range of moisture contents. The report contains the diffusion coefficients calculated by the Nernst-Einstein equation (Jurinak et al. 1987, p. 626) that become a part of the Technical Database. Raw data is also included in the report, however this data does not become part of the Technical Database as per Section 3.23 of AP-SIII.3Q ''Submittal and Incorporation of Data to the Technical Data Management System''. A sieve analysis of the samples was not conducted as part of this report, but sieve analysis may be accomplished as part of other reports. Two samples of crushed tuff and two samples of silica sand were tested
Study of Temperature Coefficients for Parameters of Photovoltaic Cells
Directory of Open Access Journals (Sweden)
Daniel Tudor Cotfas
2018-01-01
Full Text Available The temperature is one of the most important factors which affect the performance of the photovoltaic cells and panels along with the irradiance. The current voltage characteristics, I-V, are measured at different temperatures from 25°C to 87°C and at different illumination levels from 400 to 1000 W/m2, because there are locations where the upper limit of the photovoltaic cells working temperature exceeds 80°C. This study reports the influence of the temperature and the irradiance on the important parameters of four commercial photovoltaic cell types: monocrystalline silicon—mSi, polycrystalline silicon—pSi, amorphous silicon—aSi, and multijunction InGaP/InGaAs/Ge (Emcore. The absolute and normalized temperature coefficients are determined and compared with their values from the related literature. The variation of the absolute temperature coefficient function of the irradiance and its significance to accurately determine the important parameters of the photovoltaic cells are also presented. The analysis is made on different types of photovoltaics cells in order to understand the effects of technology on temperature coefficients. The comparison between the open-circuit voltage and short-circuit current was also performed, calculated using the temperature coefficients, determined, and measured, in various conditions. The measurements are realized using the SolarLab system, and the photovoltaic cell parameters are determined and compared using the LabVIEW software created for SolarLab system.
Determination of corneal elasticity coefficient using the ORA database.
Avetisov, Sergei E; Novikov, Ivan A; Bubnova, Irina A; Antonov, Alexei A; Siplivyi, Vladimir I
2010-07-01
To propose a new approach for the study of corneal biomechanics using the Reichert Ocular Response Analyzer (ORA) database, which is based on changes in velocity retardation in the central cornea at the peak of flattening. The ORA applanation curve was analyzed using a mathematical technique, which allowed calculation of the elasticity coefficient (Ke), which is primarily characteristic of the elastic properties of the cornea. Elasticity coefficient values were obtained in patients with presumably different biomechanical properties of the cornea: "normal" cornea (71 eyes, normal group), keratoconus (34 eyes, keratoconus group), LASIK (36 eyes, LASIK group), and glaucoma with elevated and compensated intraocular pressure (lOP) (38 eyes, glaucoma group). The mean Ke value in the normal group was 11.05 +/- 1.6, and the corneal thickness correlation coefficient r2 was 0.48. In the keratoconus group, the mean Ke value was 4.91 +/- 1.87 and the corneal thickness correlation coefficient r2 was 0.47. In the LASIK group, Ke and r2 were 5.99 +/- 1.18 and 0.39, respectively. In the glaucoma group, the same eyes that experienced a two-fold reduction in lOP developed a statistically significant reduction in the Ke (1.06 times lower), whereas their corneal hysteresis value increased 1.25 times. The elasticity coefficient calculated using the ORA applanation curve can be used in the evaluation of corneal biomechanical properties.
Induration and Biot’s Coefficient of Palaeogene Limestone
DEFF Research Database (Denmark)
Andreassen, Katrine Alling
2017-01-01
In engineering geology and classification of rock masses for civil engineering purposes, the degree of induration for a rock serves as a useful classification parameter. Induration is a measure of how well the grains of a sedimentary rock are cemented together - from loosely cemented/soft rock...... to very competent/slightly metamorphic rock. The Biot coefficient links to the degree of cementation in the capacity of how it relates the elastic deformations with the change in pore pressure. A hypothesis is that the degree of induration could be correlated to the magnitude of the Biot coefficient....... This is tested on 11 Copenhagen Limestone specimens of varying porosity and densities obtained from one borehole with a limestone interval of 30 m. Their induration varies from H2 to H5. Elastic wave propagation measurements are used to establish the Biot coefficient and determination of the mineralogy for H5...
Studies on absorption coefficient near edge of multi elements
International Nuclear Information System (INIS)
Eisa, M.H.; Shen, H.; Yao, H.Y.; Mi, Y.; Zhou, Z.Y.; Hu, T.D.; Xie, Y.N.
2005-01-01
X-ray absorption near edge structure (XANES) was used to study the near edge mass-absorption coefficients of seven elements, such as, Ti, V, Fe, Co, Ni, Cu and Zn. It is well known that, on the near edge absorption of element, when incident X-ray a few eV change can make the absorption coefficient an order magnitude alteration. So that, there are only a few points mass-absorption coefficient at the near edge absorption and that always average value in published table. Our results showed a wide range of data, the total measured data of mass-absorption coefficient of the seven elements was about 505. The investigation confirmed that XANES is useful technique for multi-element absorption coefficient measurement. Details of experimental methods and results are given and discussed. The experimental work has been performed at Beijing Synchrotron Radiation Facility. The measured values were compared with the published data. Good agreement between experimental results and published data is obtained
Studies on absorption coefficient near edge of multi elements
Eisa, M. H.; Shen, H.; Yao, H. Y.; Mi, Y.; Zhou, Z. Y.; Hu, T. D.; Xie, Y. N.
2005-12-01
X-ray absorption near edge structure (XANES) was used to study the near edge mass-absorption coefficients of seven elements, such as, Ti, V, Fe, Co, Ni, Cu and Zn. It is well known that, on the near edge absorption of element, when incident X-ray a few eV change can make the absorption coefficient an order magnitude alteration. So that, there are only a few points mass-absorption coefficient at the near edge absorption and that always average value in published table. Our results showed a wide range of data, the total measured data of mass-absorption coefficient of the seven elements was about 505. The investigation confirmed that XANES is useful technique for multi-element absorption coefficient measurement. Details of experimental methods and results are given and discussed. The experimental work has been performed at Beijing Synchrotron Radiation Facility. The measured values were compared with the published data. Good agreement between experimental results and published data is obtained.
Clebsch-Gordan coefficients of discrete groups in subgroup bases
Chen, Gaoli
2018-04-01
We express each Clebsch-Gordan (CG) coefficient of a discrete group as a product of a CG coefficient of its subgroup and a factor, which we call an embedding factor. With an appropriate definition, such factors are fixed up to phase ambiguities. Particularly, they are invariant under basis transformations of irreducible representations of both the group and its subgroup. We then impose on the embedding factors constraints, which relate them to their counterparts under complex conjugate and therefore restrict the phases of embedding factors. In some cases, the phase ambiguities are reduced to sign ambiguities. We describe the procedure of obtaining embedding factors and then calculate CG coefficients of the group 𝒫𝒮ℒ2(7) in terms of embedding factors of its subgroups S4 and 𝒯7.
Influence of roughness parameters on coefficient of friction under ...
Indian Academy of Sciences (India)
S¯adhan¯a Vol. 33, Part 3, June 2008, pp. ... Surface texture and thus roughness parameters influence coefficient of friction during sliding. ..... tural irregularities and complexities of the natural system, fractal is widely used to explain the natural ...
Evaluation of coefficient of friction in bulk metal forming
Solhjoo, Soheil
In this study an upper bound analysis for cylindrical "Barrel Compression Test" (BCT) is developed. BCT method is a very simple method which can be utilized in order to evaluate quantitatively the coefficient of friction by means of just one cylindrical specimen in an upsetting test. The method is
Molar extinction coefficients of solutions of some organic compounds
Indian Academy of Sciences (India)
efficients of these compounds have been used to calculate effective atomic numbers and electron densities. The additivity ... Molar extinction coefficients; effective atomic numbers; electron density. PACS Nos 29.30. ... the radiation path and is linearly dependent on the concentration of the absorbing species. This is most ...
Experimental partition determination of octanol-water coefficients of ...
African Journals Online (AJOL)
An electrochemical method based on square wave voltammetry was developed for the measurement of octanol-water partition coefficient, LogP, for ten ferrocene derivatives. Measured LogP values ranged over two orders of magnitude, between 2.18 for 1- ferrocenylethanol and 4.38 for ferrocenyl-2-nitrophenyl.
Molar extinction coefficients of solutions of some organic compounds
Indian Academy of Sciences (India)
(C4H8O2), succinimide (C4H5NO2) as estimated from the measured absorbance of. 7 radiations in their ... species in the solution and ε is called the molar absorptivity or extinction coefficient. (l mol-1cm-1 or ... Integration of eq. (4) leads to.
Estimates of the Sampling Distribution of Scalability Coefficient H
Van Onna, Marieke J. H.
2004-01-01
Coefficient "H" is used as an index of scalability in nonparametric item response theory (NIRT). It indicates the degree to which a set of items rank orders examinees. Theoretical sampling distributions, however, have only been derived asymptotically and only under restrictive conditions. Bootstrap methods offer an alternative possibility to…
Distributing Correlation Coefficients of Linear Structure-Activity/Property Models
Directory of Open Access Journals (Sweden)
Sorana D. BOLBOACA
2011-12-01
Full Text Available Quantitative structure-activity/property relationships are mathematical relationships linking chemical structure and activity/property in a quantitative manner. These in silico approaches are frequently used to reduce animal testing and risk-assessment, as well as to increase time- and cost-effectiveness in characterization and identification of active compounds. The aim of our study was to investigate the pattern of correlation coefficients distribution associated to simple linear relationships linking the compounds structure with their activities. A set of the most common ordnance compounds found at naval facilities with a limited data set with a range of toxicities on aquatic ecosystem and a set of seven properties was studied. Statistically significant models were selected and investigated. The probability density function of the correlation coefficients was investigated using a series of possible continuous distribution laws. Almost 48% of the correlation coefficients proved fit Beta distribution, 40% fit Generalized Pareto distribution, and 12% fit Pert distribution.
Someswara Rao, Chinta; Viswanadha Raju, S.
2016-01-01
In this paper, we consider correlation coefficient, rank correlation coefficient and cosine similarity measures for evaluating similarity between Homo sapiens and monkeys. We used DNA chromosomes of genome wide genes to determine the correlation between the chromosomal content and evolutionary relationship. The similarity among the H. sapiens and monkeys is measured for a total of 210 chromosomes related to 10 species. The similarity measures of these different species show the relationship b...
Reaction of O+, CO+, and CH+ ions with atomic hydrogen
International Nuclear Information System (INIS)
Federer, W.; Villinger, H.; Howorka, F.; Lindinger, W.; Tosis, P.; Bassi, D.; Ferguson, E.
1984-01-01
Rate coefficients for reactions of the ions O + , CO + , and CH + with atomic hydrogen have been measured for the first time at 300 K. This provides basic data for the ion chemistry of planetary atmospheres, cometary atmospheres, and interstellar molecular clouds. The O + +H measurement supports quantal calculations of this reaction. The CO + +H reaction provides an example of partial spin nonconservation in a charge-transfer reaction occurring in a deep potential well. Reactions of the same ions with H 2 that have been measured elsewhere are also reported
Validity of the CT to attenuation coefficient map conversion methods
International Nuclear Information System (INIS)
Faghihi, R.; Ahangari Shahdehi, R.; Fazilat Moadeli, M.
2004-01-01
The most important commercialized methods of attenuation correction in SPECT are based on attenuation coefficient map from a transmission imaging method. The transmission imaging system can be the linear source of radioelement or a X-ray CT system. The image of transmission imaging system is not useful unless to replacement of the attenuation coefficient or CT number with the attenuation coefficient in SPECT energy. In this paper we essay to evaluate the validity and estimate the error of the most used method of this transformation. The final result shows that the methods which use a linear or multi-linear curve accept a error in their estimation. The value of mA is not important but the patient thickness is very important and it can introduce a error more than 10 percent in the final result
Anomalous behavior of the diffusion coefficient in thin active films
International Nuclear Information System (INIS)
Basu, Abhik; Joanny, Jean-Francois; Prost, Jacques; Jülicher, Frank
2012-01-01
Inspired by recent experiments in cell biology, we elucidate the visco-elastic properties of an active gel by studying the dynamics of a small tracer particle inside it. In a stochastic hydrodynamic approach for an active gel of finite thickness L, we calculate the mean square displacement of a particle. These particle displacements are governed by fluctuations in the velocity field. We characterize the short-time behavior when the gel is a solid as well as the limit of long times when the gel becomes a fluid and the particle shows simple diffusion. Active stresses together with local polar order give rise to velocity fluctuations that lead to characteristic behaviors of the diffusion coefficient that differ fundamentally from those found in a passive system: the diffusion coefficient can depend on system size and diverges as L approaches an instability threshold. Furthermore, the diffusion coefficient becomes independent of the particle size in this case. (paper)
International Nuclear Information System (INIS)
Hanaki, Hiroshi; Sanda, Toshio; Ohashi, Masahisa
2008-10-01
To develop nuclear design of LMFBR cores, they are important subjects of research and development to improve the accuracy in nuclear design of large LMFBR cores and to design highly efficient core more rationally. The adjusted nuclear cross-sections library has been made by being reflected the result of critical experiment of the JUPITER, etc. effectively as much as possible. And the distinct improvement of the accuracy in nuclear design of large LMFBR cores has been achieved. In the design of large LMFBR cores, however, it is important to accurately estimate not only nuclear characteristics, for example, reaction rate distribution and control rod worth but also burnup characteristics, for example, burnup reactivity loss, breeding ratio and so on. Therefore, it is thought to improve the prediction accuracy for burnup characteristics using many burnup data of 'Joyo' effectively. It is thought the best way to adjust cross sections using sensitivity coefficients of burnup characteristics to utilize burnup data of 'Joyo'. It is able to know the accuracy quantitatively for burnup characteristics of large LMFBR by analyzing the sensitivity coefficients. Therefore in this work computer codes for analyzing sensitivity coefficients of burnup characteristics had been prepared since 1992. In 1992 cross-section adjustment was done by using the data of 'Joyo' and the effect was studied. In this year the adequacy of the codes was studied with a view of applying of design of large LMFBR cores. The results are as follows: (1) The computer codes which could analyze sensitivity coefficients of burnup characteristics taking into consideration plural cycles and refueling were prepared, therefore it came of be able to adjust cross sections using burnup data and to estimate the accuracy for design of large LMFBR cores. The characteristics are not only burnup reactivity loss, breeding ratio but also number density, criticality, reactivity worth, reaction rate ratio, and reaction rate
Coupling coefficients for tensor product representations of quantum SU(2)
International Nuclear Information System (INIS)
Groenevelt, Wolter
2014-01-01
We study tensor products of infinite dimensional irreducible * -representations (not corepresentations) of the SU(2) quantum group. We obtain (generalized) eigenvectors of certain self-adjoint elements using spectral analysis of Jacobi operators associated to well-known q-hypergeometric orthogonal polynomials. We also compute coupling coefficients between different eigenvectors corresponding to the same eigenvalue. Since the continuous spectrum has multiplicity two, the corresponding coupling coefficients can be considered as 2 × 2-matrix-valued orthogonal functions. We compute explicitly the matrix elements of these functions. The coupling coefficients can be considered as q-analogs of Bessel functions. As a results we obtain several q-integral identities involving q-hypergeometric orthogonal polynomials and q-Bessel-type functions
Coupling coefficients for tensor product representations of quantum SU(2)
Groenevelt, Wolter
2014-10-01
We study tensor products of infinite dimensional irreducible *-representations (not corepresentations) of the SU(2) quantum group. We obtain (generalized) eigenvectors of certain self-adjoint elements using spectral analysis of Jacobi operators associated to well-known q-hypergeometric orthogonal polynomials. We also compute coupling coefficients between different eigenvectors corresponding to the same eigenvalue. Since the continuous spectrum has multiplicity two, the corresponding coupling coefficients can be considered as 2 × 2-matrix-valued orthogonal functions. We compute explicitly the matrix elements of these functions. The coupling coefficients can be considered as q-analogs of Bessel functions. As a results we obtain several q-integral identities involving q-hypergeometric orthogonal polynomials and q-Bessel-type functions.
Analytical prediction of fuel assembly spacer grid loss coefficient
International Nuclear Information System (INIS)
Lim, J. S.; Nam, K. I.; Park, S. K.; Kwon, J. T.; Park, W. J.
2002-01-01
The analytical prediction model of the fuel assembly spacer grid pressure loss coefficient has been studied. The pressure loss of gap between the test section wall and spacer grid was separated from the current model and the different friction drag coefficient on spacer straps from high Reynolds number region were used to low Reynolds number region. The analytical model has been verified based on the hydraulic pressure drop test results for the spacer grids of three types for 5x5, 16x16(or 17x17) arrays. The analytical model predicts the pressure loss coefficients obtained from test results within the maximum errors of 12% and 7% for 5x5 test bundle and full size bundle, respectively, at Reynolds number 500,000 of the core operating condition. This result shows that the analytical model can be used for research and design change of the nuclear fuel assembly
Nuclear Data Uncertainty Propagation to Reactivity Coefficients of a Sodium Fast Reactor
Herrero, J. J.; Ochoa, R.; Martínez, J. S.; Díez, C. J.; García-Herranz, N.; Cabellos, O.
2014-04-01
The assessment of the uncertainty levels on the design and safety parameters for the innovative European Sodium Fast Reactor (ESFR) is mandatory. Some of these relevant safety quantities are the Doppler and void reactivity coefficients, whose uncertainties are quantified. Besides, the nuclear reaction data where an improvement will certainly benefit the design accuracy are identified. This work has been performed with the SCALE 6.1 codes suite and its multigroups cross sections library based on ENDF/B-VII.0 evaluation.
Chemical evolution coefficients for the study of galactic evolution
Energy Technology Data Exchange (ETDEWEB)
Mallik, D C.V. [Indian Inst. of Astrophysics, Bangalore
1980-05-01
A new evaluation of chemical evolution coefficients has been made using recent stellar evolution and nucleosynthesis data. The role of the low and intermediate mass stars in galactic nucleosynthesis has been emphasized. A significant amount of /sup 4/He, /sup 12/C and neutron-rich species is found to be contributed by these stars. Comparison with observed abundances suggests a primary origin of /sup 14/N. The simple model of galactic evolution with the new coefficients has been used to derive the ratio of helium to heavy element enrichment in the Galaxy. The new stellar evolution data do not explain the large value of this ratio that has been determined observationally.
Chemical evolution coefficients for the study of galactic evolution
International Nuclear Information System (INIS)
Mallik, D.C.V.
1980-01-01
A new evaluation of chemical evolution coefficients has been made using recent stellar evolution and nucleosynthesis data. The role of the low and intermediate mass stars in galactic nuclosynthesis has been emphasized. A significant amount of 4 He, 12 C and neutron-rich species is found to be contributed by these stars. Comparison with observed abundances suggests a primary origin of 14 N. The simple model of galactic evolution with the new coefficients has been used to derive the ratio of helium to heavy element enrichment in the Galaxy. The new stellar evolution data do not explain the large value of this ratio that has been determined observationally. (orig.)
Determination of Dimensionless Attenuation Coefficient in Shaped Resonators
Daniels, C.; Steinetz, B.; Finkbeiner, J.; Raman, G.; Li, X.
2003-01-01
The value of dimensionless attenuation coefficient is an important factor when numerically predicting high-amplitude acoustic waves in shaped resonators. Both the magnitude of the pressure waveform and the quality factor rely heavily on this dimensionless parameter. Previous authors have stated the values used, but have not completely explained their methods. This work fully describes the methodology used to determine this important parameter. Over a range of frequencies encompassing the fundamental resonance, the pressure waves were experimentally measured at each end of the shaped resonators. At the corresponding dimensionless acceleration, the numerical code modeled the acoustic waveforms generated in the resonator using various dimensionless attenuation coefficients. The dimensionless attenuation coefficient that most closely matched the pressure amplitudes and quality factors of the experimental and numerical results was determined to be the value to be used in subsequent studies.
Calibration coefficient of the SSNTD and equilibrium factor for radon
International Nuclear Information System (INIS)
Planinic, J.; Vukovic, B.
1993-01-01
Disintegration, ventilation and deposition were considered as removal processes of the radon and its short-lived daughters in air and respective concentration equations were applied. Calibration coefficient (K F ) of the solid state nuclear track detector (SSNTD) LR-115 for radon and the equilibrium factor (F) were related to track densities of the bare detector (D) and the filtered one (D o ). A useful relationship between K F , F and detector sensitivity coefficient (k) was derived. Using the calibrated value k=3.29 * 10 -3 m, the exposed detectors gave the average values of the equilibrium factor, calibration coefficient and indoor radon concentration of a single house living room in Osijek 0.46, 142.3 m -1 and 37.8 Bq m -3 , respectively. (author) 4 refs.; 1 fig
Distribution of temperature coefficient density for muons in the atmosphere
Directory of Open Access Journals (Sweden)
Kuzmenko V.S.
2017-12-01
Full Text Available To date, several dozens of new muon detectors have been built. When studying cosmic-ray intensity variations with these detectors, located deep in the atmosphere, it is necessary to calculate all characteristics, including the distribution of temperature coefficient density for muons in the atmosphere, taking into account their specific geometry. For this purpose, we calculate the density of temperature coefficients of muon intensity in the atmosphere at various zenith angles of detection at sea level and at various depths underground for different absorption ranges of primary protons and pions in the atmosphere.
Calculation of self-diffusion coefficients in iron
Directory of Open Access Journals (Sweden)
Baohua Zhang
2014-01-01
Full Text Available On the basis of available P-V-T equation of state of iron, the temperature and pressure dependence of self-diffusion coefficients in iron polymorphs (α, δ, γ and ɛ phases have been successfully reproduced in terms of the bulk elastic and expansivity data by means of a thermodynamical model that interconnects point defects parameters with bulk properties. The calculated diffusion parameters, such as self-diffusion coefficient, activation energy and activation volume over a broad temperature range (500-2500 K and pressure range (0-100 GPa, compare favorably well with experimental or theoretical ones when the uncertainties are considered.
Identification of MIMO systems with sparse transfer function coefficients
Qiu, Wanzhi; Saleem, Syed Khusro; Skafidas, Efstratios
2012-12-01
We study the problem of estimating transfer functions of multivariable (multiple-input multiple-output--MIMO) systems with sparse coefficients. We note that subspace identification methods are powerful and convenient tools in dealing with MIMO systems since they neither require nonlinear optimization nor impose any canonical form on the systems. However, subspace-based methods are inefficient for systems with sparse transfer function coefficients since they work on state space models. We propose a two-step algorithm where the first step identifies the system order using the subspace principle in a state space format, while the second step estimates coefficients of the transfer functions via L1-norm convex optimization. The proposed algorithm retains good features of subspace methods with improved noise-robustness for sparse systems.
An innovative method for determining the diffusion coefficient of product nuclide
Energy Technology Data Exchange (ETDEWEB)
Chen, Chih Lung [Dept. of Nuclear Back-end Management, Taiwan Power Company, Taipei (China); Wang, Tsing Hai [Dept. Biomedical Engineering and Environment Sciences, National Tsing Hua University, Hsinchu (China)
2017-08-15
Diffusion is a crucial mechanism that regulates the migration of radioactive nuclides. In this study, an innovative numerical method was developed to simultaneously calculate the diffusion coefficient of both parent and, afterward, series daughter nuclides in a sequentially reactive through-diffusion model. Two constructed scenarios, a serial reaction (RN{sub 1} → RN{sub 2} → RN{sub 3}) and a parallel reaction (RN{sub 1} → RN{sub 2}A + RN{sub 2}B), were proposed and calculated for verification. First, the accuracy of the proposed three-member reaction equations was validated using several default numerical experiments. Second, by applying the validated numerical experimental concentration variation data, the as-determined diffusion coefficient of the product nuclide was observed to be identical to the default data. The results demonstrate the validity of the proposed method. The significance of the proposed numerical method will be particularly powerful in determining the diffusion coefficients of systems with extremely thin specimens, long periods of diffusion time, and parent nuclides with fast decay constants.
Efficient calculation of atomic rate coefficients in dense plasmas
Aslanyan, Valentin; Tallents, Greg J.
2017-03-01
Modelling electron statistics in a cold, dense plasma by the Fermi-Dirac distribution leads to complications in the calculations of atomic rate coefficients. The Pauli exclusion principle slows down the rate of collisions as electrons must find unoccupied quantum states and adds a further computational cost. Methods to calculate these coefficients by direct numerical integration with a high degree of parallelism are presented. This degree of optimization allows the effects of degeneracy to be incorporated into a time-dependent collisional-radiative model. Example results from such a model are presented.
Determination of photon detector coefficient in neutron flux study
International Nuclear Information System (INIS)
Jedol Dayou; Azali Muhammad; Abd Aziz Mohamed; Abdul Razak Daud; Elias Saniman
1995-01-01
The efficiency of photon detector which is normally used in neutron flux measurement has been studied. The data obtain have been plotted using mathematical models in the form of reciprocal, exponential and semilog equation and subsequently efficiency coefficient of the detector has been determined. Beside that, energy quadratic equation model has also been used. It has been found that equation model selection is very important in the detector efficiency coefficient determination. In the case of energy quadratic equation, it has been found that the selection of energy set influenced the result. It can be concluded that energy quadratic equation is the best model in the neutron flux determination
Modification of Einstein A Coefficient in Dissipative Gas Medium
Cao, Chang-Qi; Cao, Hui; Qin, Ke-Cheng
1996-01-01
Spontaneous radiation in dissipative gas medium such as plasmas is investigated by Langevin equations and the modified Weisskopf-Wigner approximation. Since the refractive index of gas medium is expected to be nearly unity, we shall first neglect the medium polarization effect. We show that absorption in plasmas may in certain case modify the Einstein A coefficient significantly and cause a pit in the A coefficient-density curves for relatively low temperature plasmas and also a pit in the A coefficient-temperature curves. In the next, the effect of medium polarization is taken into account in addition. To our surprise, its effect in certain case is quite significant. The dispersive curves show different behaviors in different region of parameters.
Nitrogen ion implantation effect on friction coefficient of tool steel
International Nuclear Information System (INIS)
Velichko, N.I.; Udovenko, V.F.; Markus, A.M.; Presnyakova, G.N.; Gamulya, G.D.
1988-01-01
Effect of nitrogen molecular ion implantation into KhVSG steel on the friction coefficient in the air and vacuum is investigated. Irradiation is carried out by the N 2 + beam with energy 120 keV and flux density 5 μ/cm 2 at room temperature in vacuum 5x10 -4 Pa. The integral dose of irradiation is 10 17 particle/cm 2 . Nitrogen ion implantation is shown to provide the formation of the modified layer changing friction properties of steel. The friction coefficient can either increase or decrease depending on implantation and test conditions. 4 refs.; 2 figs
Substitution reactions of technetium complexes
International Nuclear Information System (INIS)
Omori, T.
1997-01-01
Substitution reactions of a series of technetium complexes are considered in comparison with corresponding reactions of rhenium. Rhenium and technetium complexes are rather inert in substitution reactions, the latter are characterized by greater rate constants when they proceed according to dissociative mechanism. In rare cases when k Tc /k Re id little it is assumed that the reaction proceeds according to the associative mechanism. (author)
The partition coefficients of 133Xe between blood and bone
International Nuclear Information System (INIS)
Lahtinen, T.; Karjalainen, P.; Vaeaenaenen, A.; Lahtinen, R.; Alhava, E.M.
1981-01-01
The partition coefficients of 133 Xe between blood and haematopoietic bone marrow and homogenised bone have been determined in vitro. The partition coefficient lambda 1 corresponding to haematopoietic marrow was 0.95 ml g -1 while that corresponding to homogenised bone was a function of age, lambda 2 = 3.11 + 0.049(age)(ml g -1 ). These data can be used for calculating regional blood flow in healthy human femur by means of a simple 133 Xe radionuclide method. (author)
Estimation of octanol/water partition coefficients using LSER parameters
Luehrs, Dean C.; Hickey, James P.; Godbole, Kalpana A.; Rogers, Tony N.
1998-01-01
The logarithms of octanol/water partition coefficients, logKow, were regressed against the linear solvation energy relationship (LSER) parameters for a training set of 981 diverse organic chemicals. The standard deviation for logKow was 0.49. The regression equation was then used to estimate logKow for a test of 146 chemicals which included pesticides and other diverse polyfunctional compounds. Thus the octanol/water partition coefficient may be estimated by LSER parameters without elaborate software but only moderate accuracy should be expected.
Calculation results and experimental testing of doppler feedback coefficients
International Nuclear Information System (INIS)
Yang Shunhai
1989-01-01
The Doppler feedback coefficients are calculated by the interpolation and group collapsing method from multigroup self-shielding factors and infinite dilution cross sections rather than effective resonance integrals by using resonance data base. Since many updated sets of multigroup data are in existence to be selected, the calculation process can be simplified. The heterogeneous effects are taken into account by equivalence relation. The computer code of Doppler feedback coefficients is created on computer CYBER-825 and PDP-11. The results calculated are in good agreement with the experiments
International Nuclear Information System (INIS)
Deev, V.I.; Sobolev, V.P.; Kruglov, A.B.; Pridantsev, A.I.
1984-01-01
Results of experimental investigation of heat conduction coefficient and coefficient of linear thermal expansion and thermal shrinkages of the STEF-1 textolite-glass widely used in superconducting magnetic systems as electric insulating and structural material are presented. Samples of two types have been died: sample axisa is perpendicular to a plae of fiberglass layers ad sample axis is parallel to a plane of fiberglass layers. Heat conduction coefficient was decreased almost a five times with temperature decrease from 300 up to 5K and was slightly dependent on a sample type. Temperature variation of linear dimensions in a sample of the first type occurs in twice as fast as compared to the sample of the second type
Methodology update for determination of the erosion coefficient(Z
Directory of Open Access Journals (Sweden)
Tošić Radislav
2012-01-01
Full Text Available The research and mapping the intensity of mechanical water erosion that have begun with the empirical methodology of S. Gavrilović during the mid-twentieth century last, by various intensity, until the present time. A many decades work on the research of these issues pointed to some shortcomings of the existing methodology, and thus the need for its innovation. In this sense, R. Lazarević made certain adjustments of the empirical methodology of S. Gavrilović by changing the tables for determination of the coefficients Φ, X and Y, that is, the tables for determining the mean erosion coefficient (Z. The main objective of this paper is to update the existing methodology for determining the erosion coefficient (Z with the empirical methodology of S. Gavrilović and amendments made by R. Lazarević (1985, but also with better adjustments to the information technologies and the needs of modern society. The proposed procedure, that is, the model to determine the erosion coefficient (Z in this paper is the result of ten years of scientific research and project work in mapping the intensity of mechanical water erosion and its modeling using various models of erosion in the Republic of Srpska and Serbia. By analyzing the correlation of results obtained by regression models and results obtained during the mapping of erosion on the territory of the Republic of Srpska, a high degree of correlation (R² = 0.9963 was established, which is essentially a good assessment of the proposed models.
Extracting OPE coefficient of Konishi at four loops
Energy Technology Data Exchange (ETDEWEB)
Goncalves, Vasco [ICTP South American Institute for Fundamental Research Instituto de Fisica Teorica,UNESP, Universidad Estadual Paulista, Rua Dr. Bento T. Ferraz 271, 01140-070, Sao Paulo, SP (Brazil)
2017-03-15
In this short note we compute the OPE coefficient of two 20{sup ′} operators and the Konishi operator. To this end, we use the OPE decomposition of a four point function of four 20{sup ′} operators and the method of asymptotic expansions to compute the leading term, in the OPE limit, of all integrals contributing to the four point function.
A Simple Measurement of the Sliding Friction Coefficient
Gratton, Luigi M.; Defrancesco, Silvia
2006-01-01
We present a simple computer-aided experiment for investigating Coulomb's law of sliding friction in a classroom. It provides a way of testing the possible dependence of the friction coefficient on various parameters, such as types of materials, normal force, apparent area of contact and sliding velocity.
Calculation of generalized secant integral using binomial coefficients
International Nuclear Information System (INIS)
Guseinov, I.I.; Mamedov, B.A.
2004-01-01
A single series expansion relation is derived for the generalized secant (GS) integral in terms of binomial coefficients, exponential integrals and incomplete gamma functions. The convergence of the series is tested by the concrete cases of parameters. The formulas given in this study for the evaluation of GS integral show good rate of convergence and numerical stability
Modification of van La ar activity coefficient model
International Nuclear Information System (INIS)
Vakili-Nezhaad, G. R.; Modarress, H.; Mansoori, G. A.
2001-01-01
Based on statistical and mechanical arguments, the original van La ar activity coefficient model has been improved by reasonable assumptions. This modifications has been done by replacing the van der Waals equation of state with the Redlich-K wong equation of state in the formulation of van La ar with consistent mixing rules for the energy and volume parameters of this equation of state (a mix , b mix ). Other equations of state, such as the Soave modification of the Redlich-K wong equation of state, P eng-Robinson and Mohsen-Nia, Modarress and Mansoori equations of state, have been introduced in the formulation of van La ar for the activity coefficients of the components present in the binary liquid mixtures, and their effects on the accuracy of the resultant activity coefficient models have been examined. The results of these revised models have been compared with the experimental data and it was found that the Redlich-K wong equation of state with the van der Waals mixing rules for the volume and energy parameters of this equation, is the best choice among these equations of state. In addition, it can improve the original van La ar activity coefficient model and, therefore a better agreement with the experimental data is obtained
Regression Models for Predicting Force Coefficients of Aerofoils
Directory of Open Access Journals (Sweden)
Mohammed ABDUL AKBAR
2015-09-01
Full Text Available Renewable sources of energy are attractive and advantageous in a lot of different ways. Among the renewable energy sources, wind energy is the fastest growing type. Among wind energy converters, Vertical axis wind turbines (VAWTs have received renewed interest in the past decade due to some of the advantages they possess over their horizontal axis counterparts. VAWTs have evolved into complex 3-D shapes. A key component in predicting the output of VAWTs through analytical studies is obtaining the values of lift and drag coefficients which is a function of shape of the aerofoil, ‘angle of attack’ of wind and Reynolds’s number of flow. Sandia National Laboratories have carried out extensive experiments on aerofoils for the Reynolds number in the range of those experienced by VAWTs. The volume of experimental data thus obtained is huge. The current paper discusses three Regression analysis models developed wherein lift and drag coefficients can be found out using simple formula without having to deal with the bulk of the data. Drag coefficients and Lift coefficients were being successfully estimated by regression models with R2 values as high as 0.98.
Coefficient of friction of a starved lubricated spur gear pair
International Nuclear Information System (INIS)
Liu, Huaiju; Zhu, Caichao; Sun, Zhangdong; Zhang, Yuanyuan; Song, Chaosheng
2016-01-01
The frictional power loss issue of gear pairs becomes an important concern in both industry and academia due to the requirement of the energy saving and the improvement of power density of gear drives. A thermal starved elastohydrodynamic lubrication model is developed to study the tribological performance of a spur gear pair under starved lubrication conditions. The contact pressure, the film thickness, the temperature rise, the frictional power loss, as well as the coefficient of friction are evaluated by considering the variation of the curvature radius, the sliding/rolling motion, and the load distribution of gear tooth within the meshing period. Effects of lubrication starvation condition, load and speed on the coefficient of friction are studied.
Coefficient of restitution of sports balls: A normal drop test
International Nuclear Information System (INIS)
Haron, Adli; Ismail, K A
2012-01-01
Dynamic behaviour of bodies during impact is investigated through impact experiment, the simplest being a normal drop test. Normally, a drop test impact experiment involves measurement of kinematic data; this includes measurement of incident and rebound velocity in order to calculate a coefficient of restitution (COR). A high speed video camera is employed for measuring the kinematic data where speed is calculated from displacement of the bodies. Alternatively, sensors can be employed to measure speeds, especially for a normal impact where there is no spin of the bodies. This paper compares experimental coefficients of restitution (COR) for various sports balls, namely golf, table tennis, hockey and cricket. The energy loss in term of measured COR and effects of target plate are discussed in relation to the material and construction of these sports balls.
Friction analysis of kinetic schemes : the friction coefficient
Lolkema, Juke S.
1995-01-01
Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free
Determination of Water Requirement and Crop Coefficient for ...
African Journals Online (AJOL)
Knowledge of crop evapotranspiration (ETc), the combined process of evaporation and plant transpiration, is important in agriculture for scheduling farm operations and designing and managing irrigation and drainage systems. Development of crop coefficient (Kc) can enhance crop evapotranspiration (ETc) estimates in ...
Measurement of atomic number and mass attenuation coefficient in ...
Indian Academy of Sciences (India)
literature on the measurement of mass attenuation coefficient in magnesium ferrite. The knowledge of photon ... pure) MgO and Fe2O3. The details of experimental ... and (4 4 0) planes belonging to cubic spinel structure. The XRD pattern ...
Measurement of heat transfer coefficient using termoanemometry methods
Dančová, P.; Sitek, P.; Vít, T.
2014-03-01
This work deals with a measurement of heat transfer from a heated flat plate on which a synthetic jet impacts perpendicularly. Measurement of a heat transfer coefficient (HTC) is carried out using the hot wire anemometry method with glue film probe Dantec 55M47. The paper brings also results of velocity profiles measurements and turbulence intensity calculations.
Measurement of heat transfer coefficient using termoanemometry methods
Directory of Open Access Journals (Sweden)
Dančová P.
2014-03-01
Full Text Available This work deals with a measurement of heat transfer from a heated flat plate on which a synthetic jet impacts perpendicularly. Measurement of a heat transfer coefficient (HTC is carried out using the hot wire anemometry method with glue film probe Dantec 55M47. The paper brings also results of velocity profiles measurements and turbulence intensity calculations.
Determination of the Static Friction Coefficient from Circular Motion
Molina-Bolívar, J. A.; Cabrerizo-Vílchez, M. A.
2014-01-01
This paper describes a physics laboratory exercise for determining the coefficient of static friction between two surfaces. The circular motion of a coin placed on the surface of a rotating turntable has been studied. For this purpose, the motion is recorded with a high-speed digital video camera recording at 240 frames s[superscript-1], and the…
Molar extinction coefficients of some carbohydrates in aqueous ...
Indian Academy of Sciences (India)
of plants and animals, both as structural elements and in the maintenance of functional ... In this paper we report the molar extinction coefficient ε, of carbohydrates ... as the area, which has to be hit by the photons in order to cause interaction.
ROVIBRATIONAL QUENCHING RATE COEFFICIENTS OF HD IN COLLISIONS WITH He
International Nuclear Information System (INIS)
Nolte, J. L.; Stancil, P. C.; Lee, T.-G.; Balakrishnan, N.; Forrey, R. C.
2012-01-01
Along with H 2 , HD has been found to play an important role in the cooling of the primordial gas for the formation of the first stars and galaxies. It has also been observed in a variety of cool molecular astrophysical environments. The rate of cooling by HD molecules requires knowledge of collisional rate coefficients with the primary impactors, H, He, and H 2 . To improve knowledge of the collisional properties of HD, we present rate coefficients for the He-HD collision system over a range of collision energies from 10 –5 to 5 × 10 3 cm –1 . Fully quantum mechanical scattering calculations were performed for initial HD rovibrational states of j = 0 and 1 for v = 0-17 which utilized accurate diatom rovibrational wave functions. Rate coefficients of all Δv = 0, –1, and –2 transitions are reported. Significant discrepancies with previous calculations, which adopted a small basis and harmonic HD wave functions for excited vibrational levels, were found for the highest previously considered vibrational state of v = 3. Applications of the He-HD rate coefficients in various astrophysical environments are briefly discussed.
Value of apparent diffusion coefficient (ADC) in evaluating response ...
African Journals Online (AJOL)
Objective. To determine whether the apparent diffusion coefficient (ADC) value obtained by diffusion-weighted magnetic resonance imaging (DW-MRI) can be used as a reliable detector of response of carcinoma of the cervix treated with chemoradiotherapy, compared with conventional. T2-weighted MRI. Design.
Evaluation of coefficient of friction in bulk metal forming
Solhjoo, Soheil
2014-01-01
In this study an upper bound analysis for cylindrical "Barrel Compression Test" (BCT) is developed. BCT method is a very simple method which can be utilized in order to evaluate quantitatively the coefficient of friction by means of just one cylindrical specimen in an upsetting test. The method is checked by a series of finite element method (FEM) simulations and by means of the results of FEM simulations the method is modified.
Density dependence of the diffusion coefficient of alkali metals
International Nuclear Information System (INIS)
Adebayo, G.A.; Anusionwu, B.C.; Njah, A.N.; Mathew, B.; Fabamise, O.A.T.
2004-06-01
The effect of density on transport coefficients of liquid Li, Na and K at high temperatures using the method of Molecular Dynamics simulation has been studied. Simulation of these liquid alkali metals were carried out with 800 particles in simulation boxes with periodic boundary conditions imposed. In order to test the reliability of the interatomic potential used in the calculations, experimental data on the structural properties were compared with calculated results. The calculations showed a linear relationship between the density and the diffusion coefficient in all the systems investigated except in lithium, where, due to the small size of the atom, standard molecular dynamics simulation method may not be appropriate for calculating the properties of interest. (author)
Modeling the Design Flow Coefficient of a Centrifugal Compressor Impeller
Directory of Open Access Journals (Sweden)
A. A. Drozdov
2017-01-01
Full Text Available In calculating gas-dynamic characteristics by the universal modeling method it is necessary to determine a non-incidence flow rate through the blades of an impeller because of its relationship with the magnitude of incidence losses. The flow area decreased by the blades of finite thickness and the blades load have impact on the critical streamline direction. The universal modeling method in primary designing uses for this a scheme of replacing the influence of the blade load by the vortex effect with identical circulation. Finally, calculating the inviscid flow around the blades allows selecting a value of the inlet blade angle. For impellers with small design flow coefficients, the condition of the non-incidence inlet for the primary design and for the calculation of the inviscid flow is significantly different. The calculating correctness of the non-incidence regime for the non-viscous flow was checked earlier by measurements of the flow in the impellers. The paper presents CFD calculations of twenty impellers in a tenfold range of design flow coefficients. To provide correct comparison, it takes into account the differences in the value of the loading factor calculated by the programs of inviscid quasi-three-dimensional calculation and CFD programs. Shows the identity of inlet conditions for both methods. To increase primary design accuracy, the calculation model was refined. The formula for calculating vortex-induced velocity involves an empirical coefficient. The analysis of data for 32 impellers with different blade profiling allowed working out formulas for calculating empirical coefficient, depending on the type of an impeller, the blade load and the width of the throat at an impeller inlet. The new scheme-based calculation with the empirical coefficient is accurate enough for the primary design.
Distribution coefficient of plutonium between sediment and seawater
International Nuclear Information System (INIS)
Duursma, E.K.; Parsi, P.
1974-01-01
Using plutonium 237 as a tracer, a series of experiments were conducted to determine the distribution coefficient of plutonium onto sediments both under oxic and anoxic conditions, where the plutonium was added to seawater in three different valence states: III, IV and VI
Measurements of gaseous multiplication coefficient in pure isobutane
International Nuclear Information System (INIS)
Lima, Iara Batista de
2010-01-01
In this work it is presented measurements of gaseous multiplication coefficient (α) in pure isobutane obtained with a parallel plate chamber, protected against discharges by one electrode (anode) of high resistivity glass (ρ = 2 x 10 12 Ω.cm). The method applied was the Pulsed Townsend, where the primary ionization is produced through the incidence of a nitrogen laser beam onto a metallic electrode (cathode). The electric currents measured with the chamber operating in both ionization and avalanche regimes were used to calculate the gaseous multiplication coefficient by the solution of the Townsend equation for uniform electric fields. The validation of the technique was provided by the measurements of gaseous multiplication coefficient in pure nitrogen, a widely studied gas, which has well-established data in literature. The α coefficients in isobutane were measured as a function of the reduced electric field in the range of 139Td up to 208Td. The obtained values were compared with those simulated by Imonte software (version 4.5) and the only experimental results available in the literature, recently obtained in our group. This comparison showed that the results are concordant within the experimental errors. (author)
Thermal lensing measurement from the coefficient of defocus aberration
CSIR Research Space (South Africa)
Bell, Teboho
2016-03-01
Full Text Available We measured the thermally induced lens from the coefficient of defocus aberration using a Shack-Hartmann wavefront sensor (SHWFS). As a calibration technique, we infer the focal length of standard lenses probed by a collimated Gaussian beam...
Thermally induced lensing determination from the coefficient of defocus aberration
CSIR Research Space (South Africa)
Bell, Teboho
2014-07-01
Full Text Available The effects of a temperature gradient in a laser crystal in an end-pumped configuration in a solid-state laser resonator results in thermally induced aberrations. Of particular interest we measure the thermally induced lens from the coefficient...
Coefficient Estimate Problem for a New Subclass of Biunivalent Functions
N. Magesh; T. Rosy; S. Varma
2013-01-01
We introduce a unified subclass of the function class Σ of biunivalent functions defined in the open unit disc. Furthermore, we find estimates on the coefficients |a2| and |a3| for functions in this subclass. In addition, many relevant connections with known or new results are pointed out.
Visualising the Complex Roots of Quadratic Equations with Real Coefficients
Bardell, Nicholas S.
2012-01-01
The roots of the general quadratic equation y = ax[superscript 2] + bx + c (real a, b, c) are known to occur in the following sets: (i) real and distinct; (ii) real and coincident; and (iii) a complex conjugate pair. Case (iii), which provides the focus for this investigation, can only occur when the values of the real coefficients a, b, and c are…
Study of distribution coefficients of admixtures in tellurium
International Nuclear Information System (INIS)
Kuchar, L.; Drapala, J.; Kuchar, L. jr.
1986-01-01
Limit areas of tellurium-admixture binary systems were studied and the values determined of steady-state distribution coefficients of admixtures. A second order polynomial was used to express equations of solidus and liquidus curves for Te-Se, Te-S, Te-Hg systems; the curves are graphically represented. The most effective method for preparing high-purity tellurium is zonal melting with material removal. (M.D.). 4 figs., 4 tabs., 16 refs
Quenching of Einstein A-Coefficients in plasmas and lasers
International Nuclear Information System (INIS)
Suckewer, S.; Princeton Univ., NJ
1991-03-01
The coefficient of spontaneous emission (Einstein A-coefficient) is considered to be one of the basic constants of a given transition in atom or ion. The formula for the Einstein A-coefficient was derived in the pioneering works of Weisskopf and Wigner (WW) based on Dirac's theory of light. More recently, however, it was noted in several papers that the rate of spontaneous radiative decay can deviate significantly from the WW expression in certain conditions, for example in a laser cavity. A different type of change in A- coefficients was inferred from measurements of changes in the intensity branching ratio of spectral lines in a plasma. A change of branching ratio of up to a factor of 10 was observed in CIV for 3p-3s (580.1--581.2nm) and 3p-2s (31.2-nm) transitions when the electron density changed from approximately N e ∼ 1 x 10 18 to 5 x 10 18 cm -3 . This effect was also observed in CIII and NV. An initial theoretical approach to the problem based on the integration of the Schroedinger equation with the ion Coulomb potential modified by the electron cloud within the Debye radius was unsuccessfully in predicting the experimental observations. The effect of quenching of spontaneous emission coefficients was observed also in an Ar-ion laser as a function of the intracavity power density (photon density) for lines originating from the same upper level as the lasing line. Measurements of these line profiles absorption for different lasing conditions and related discussions are also presented. 14 refs., 6 figs
Dielectronic recombination rate coefficients of initially rubidium-like tungsten
International Nuclear Information System (INIS)
Wu, Z.; Zhang, Y.; Fu, Y.; Dong, C.; Surzhykov, A.; Fritzsche, S.
2015-01-01
Dielectric recombination (DR) is a dominant electron recombination process in plasmas. Tungsten ions are expected to be prominent impurities in fusion plasmas so the knowledge of DR rate coefficient of tungsten ions is important to model fusion plasmas. Ab initio calculations of DR rate coefficients of initially rubidium-like W 37+ ions have been performed for the electron temperatures from 1 eV to 5*10 4 eV, by using the Flexible Atomic Code based on the relativistic configuration-interaction method. Special attention has been paid to the partial contributions to total DR rate coefficients as associated with the excitation of individual subshells. A detailed comparison of the calculations shows that the excitation from 4p subshell dominates total DR rate coefficients followed by the excitations from 4s and 4d subshells, while the contribution of excitations from 3l (l = s, p, d) subshells becomes important only at high temperatures. Besides, it is found that the electron excitations associated with Δn = 0, 1 dominate at low-temperature plasmas, however, the excitations associated with Δn ≥ 2 become non-negligible at high-temperature ones
The coefficient of restitution of pressurized balls: a mechanistic model
Georgallas, Alex; Landry, Gaëtan
2016-01-01
Pressurized, inflated balls used in professional sports are regulated so that their behaviour upon impact can be anticipated and allow the game to have its distinctive character. However, the dynamics governing the impacts of such balls, even on stationary hard surfaces, can be extremely complex. The energy transformations, which arise from the compression of the gas within the ball and from the shear forces associated with the deformation of the wall, are examined in this paper. We develop a simple mechanistic model of the dependence of the coefficient of restitution, e, upon both the gauge pressure, P_G, of the gas and the shear modulus, G, of the wall. The model is validated using the results from a simple series of experiments using three different sports balls. The fits to the data are extremely good for P_G > 25 kPa and consistent values are obtained for the value of G for the wall material. As far as the authors can tell, this simple, mechanistic model of the pressure dependence of the coefficient of restitution is the first in the literature. *%K Coefficient of Restitution, Dynamics, Inflated Balls, Pressure, Impact Model
Reaction mechanisms of metal complexes
Hay, R W
2000-01-01
This text provides a general background as a course module in the area of inorganic reaction mechanisms, suitable for advanced undergraduate and postgraduate study and/or research. The topic has important research applications in the metallurgical industry and is of interest in the science of biochemistry, biology, organic, inorganic and bioinorganic chemistry. In addition to coverage of substitution reactions in four-, five- and six-coordinate complexes, the book contains further chapters devoted to isomerization and racemization reactions, to the general field of redox reactions, and to the reactions of coordinated ligands. It is relevant in other fields such as organic, bioinorganic and biological chemistry, providing a bridge to organic reaction mechanisms. The book also contains a chapter on the kinetic background to the subject with many illustrative examples which should prove useful to those beginning research. Provides a general background as a course module in the area of inorganic reaction mechanis...
A comparison of two indices for the intraclass correlation coefficient.
Shieh, Gwowen
2012-12-01
In the present study, we examined the behavior of two indices for measuring the intraclass correlation in the one-way random effects model: the prevailing ICC(1) (Fisher, 1938) and the corrected eta-squared (Bliese & Halverson, 1998). These two procedures differ both in their methods of estimating the variance components that define the intraclass correlation coefficient and in their performance of bias and mean squared error in the estimation of the intraclass correlation coefficient. In contrast with the natural unbiased principle used to construct ICC(1), in the present study it was analytically shown that the corrected eta-squared estimator is identical to the maximum likelihood estimator and the pairwise estimator under equal group sizes. Moreover, the empirical results obtained from the present Monte Carlo simulation study across various group structures revealed the mutual dominance relationship between their truncated versions for negative values. The corrected eta-squared estimator performs better than the ICC(1) estimator when the underlying population intraclass correlation coefficient is small. Conversely, ICC(1) has a clear advantage over the corrected eta-squared for medium and large magnitudes of population intraclass correlation coefficient. The conceptual description and numerical investigation provide guidelines to help researchers choose between the two indices for more accurate reliability analysis in multilevel research.
Thermal Coefficient of Redox Potential of Alkali Metals
Fukuzumi, Yuya; Hinuma, Yoyo; Moritomo, Yutaka
2018-05-01
The thermal coefficient (α) of redox potential (V) is a significant physical quantity that converts the thermal energy into electric energy. In this short note, we carefully determined α of alkali metals (A = Li and Na) against electrolyte solution. The obtained α is much larger than that expected from the specific heat (CpA) of solid A and depends on electrolyte solution. These observations indicate that the solvent has significant effect on α.
Introduction and application of the multiscale coefficient of variation analysis.
Abney, Drew H; Kello, Christopher T; Balasubramaniam, Ramesh
2017-10-01
Quantifying how patterns of behavior relate across multiple levels of measurement typically requires long time series for reliable parameter estimation. We describe a novel analysis that estimates patterns of variability across multiple scales of analysis suitable for time series of short duration. The multiscale coefficient of variation (MSCV) measures the distance between local coefficient of variation estimates within particular time windows and the overall coefficient of variation across all time samples. We first describe the MSCV analysis and provide an example analytical protocol with corresponding MATLAB implementation and code. Next, we present a simulation study testing the new analysis using time series generated by ARFIMA models that span white noise, short-term and long-term correlations. The MSCV analysis was observed to be sensitive to specific parameters of ARFIMA models varying in the type of temporal structure and time series length. We then apply the MSCV analysis to short time series of speech phrases and musical themes to show commonalities in multiscale structure. The simulation and application studies provide evidence that the MSCV analysis can discriminate between time series varying in multiscale structure and length.
Non-Markovian dynamics of quantum systems: formalism, transport coefficients
International Nuclear Information System (INIS)
Kanokov, Z.; Palchikov, Yu.V.; Antonenko, N.V.; Adamian, G.G.; Kanokov, Z.; Adamian, G.G.; Scheid, W.
2004-01-01
Full text: The generalized Linbland equations with non-stationary transport coefficients are derived from the Langevin equations for the case of nonlinear non-Markovian noise [1]. The equations of motion for the collective coordinates are consistent with the generalized quantum fluctuation dissipation relations. The microscopic justification of the Linbland axiomatic approach is performed. Explicit expressions for the time-dependent transport coefficients are presented for the case of FC- and RWA-oscillators and a general linear coupling in coordinate and in momentum between the collective subsystem and heat bath. The explicit equations for the correlation functions show that the Onsanger's regression hypothesis does not hold exactly for the non-Markovian equations of motion. However, under some conditions the regression of fluctuations goes to zero in the same manner as the average values. In the low and high temperature regimes we found that the dissipation leads to long-time tails in correlation functions in the RWA-oscillator. In the case of the FC-oscillator a non-exponential power-like decay of the correlation function in coordinate is only obtained only at the low temperature limit. The calculated results depend rather weakly on the memory time in many applications. The found transient times for diffusion coefficients D pp (t), D qp (t) and D qq (t) are quite short. The value of classical diffusion coefficients in momentum underestimates the asymptotic value of quantum one D pp (t), but the asymptotic values of classical σ qq c and quantum σ qq second moments are close due to the negativity of quantum mixed diffusion coefficient D qp (t)
Variability, correlation and path coefficient analysis of seedling traits ...
African Journals Online (AJOL)
use
2011-12-12
Dec 12, 2011 ... Indirect selection is a useful means for improving yield in cotton crop. The objective of the present study was to determine the genetic variability, broad sense heritability, genetic advance and correlation among the six seedling traits and their direct and indirect effects on cotton yield by using path coefficient ...
Statistical analyses of local transport coefficients in Ohmic ASDEX discharges
International Nuclear Information System (INIS)
Simmet, E.; Stroth, U.; Wagner, F.; Fahrbach, H.U.; Herrmann, W.; Kardaun, O.J.W.F.; Mayer, H.M.
1991-01-01
Tokamak energy transport is still an unsolved problem. Many theoretical models have been developed, which try to explain the anomalous high energy-transport coefficients. Up to now these models have been applied to global plasma parameters. A comparison of transport coefficients with global confinement time is only conclusive if the transport is dominated by one process across the plasma diameter. This, however, is not the case in most Ohmic confinement regimes, where at least three different transport mechanisms play an important role. Sawtooth activity leads to an increase in energy transport in the plasma centre. In the intermediate region turbulent transport is expected. Candidates here are drift waves and resistive fluid turbulences. At the edge, ballooning modes or rippling modes could dominate the transport. For the intermediate region, one can deduce theoretical scaling laws for τ E from turbulent theories. Predicted scalings reproduce the experimentally found density dependence of τ E in the linear Ohmic confinement regime (LOC) and the saturated regime (SOC), but they do not show the correct dependence on the isotope mass. The relevance of these transport theories can only be tested in comparing them to experimental local transport coefficients. To this purpose we have performed transport calculations on more than a hundred Ohmic ASDEX discharges. By Principal Component Analysis we determine the dimensionless components which dominate the transport coefficients and we compare the results to the predictions of various theories. (author) 6 refs., 2 figs., 1 tab
Variability, correlation and path coefficient analysis of seedling traits ...
African Journals Online (AJOL)
Indirect selection is a useful means for improving yield in cotton crop. The objective of the present study was to determine the genetic variability, broad sense heritability, genetic advance and correlation among the six seedling traits and their direct and indirect effects on cotton yield by using path coefficient analysis.
Quantum elasticity of graphene: Thermal expansion coefficient and specific heat
Burmistrov, I.S.; Gornyi, I.V.; Kachorovskii, V.Y.; Katsnelson, M.I.; Mirlin, A.D.
2016-01-01
We explore thermodynamics of a quantum membrane, with a particular application to suspended graphene membrane and with a particular focus on the thermal expansion coefficient. We show that an interplay between quantum and classical anharmonicity-controlled fluctuations leads to unusual elastic
Determination of the chloride diffusion coefficient in blended cement mortars
Elfmarkova, V.; Spiesz, P.R.; Brouwers, H.J.H.
2015-01-01
The rapid chloride migration test (RCM) is a commonly used accelerated test for the determination of the chloride diffusion coefficient in concrete. Nevertheless, the initial development and further experience with the RCM test concern mainly the ordinary Portland cement system. Therefore, the
On the misinterpretation of the correlation coefficient in pharmaceutical sciences
DEFF Research Database (Denmark)
Sonnergaard, Jørn
2006-01-01
The correlation coefficient is often used and more often misused as a universal parameter expressing the quality in linear regression analysis. The popularity of this dimensionless quantity is evident as it is easy to communicate and considered to be unproblematic to comprehend. However, illustra...
Estimation of bulk transfer coefficient for latent heat flux (Ce)
Digital Repository Service at National Institute of Oceanography (India)
Sadhuram, Y.
The bulk transfer coefficient for latent heat flux (Ce) has been estimated over the Arabian Sea from the moisture budget during the pre-monsoon season of 1988. The computations have been made over two regions (A: 0-8 degrees N: 60-68 degrees E: B: 0...
Effects of variable sticking coefficients on the stability of reactive sputtering process
International Nuclear Information System (INIS)
Li Chuan; Hsieh Janghsing
2004-01-01
In reactive sputtering, the introduction of a reactive gas can lead to a hysteresis transition from metal to compounds in both the target and substrate. The hysteresis transition is characterized by a sudden change in partial pressure, sputtering rate, fraction of compound formation, etc. Therefore, stability is an important issue in the process control. In this paper, a mathematical model with variable sticking coefficients based on surface kinetics is used to study the stability of the process. The variable sticking coefficient represents different mechanisms for surface reactions from the Langmuir to precursor type. In order to facilitate the analysis, several nondimensional parameters are identified and used for formulation. Results show that an unsteady system converges to a steady state relatively fast at low inflow rates. With an eigenvalue analysis, the range of positive eigenvalues is consistent with the presence of a hysteresis loop. It is also found that when the chemical reaction on the substrate is moderate, a higher sputter yield of the compound leads to a more stable steady state at lower inflow rates. Regarding the sticking mechanism, for the type of precursors with the parameter k < 1, the compound is easier to form and saturate on the surface due to the higher default sticking coefficient and the lower operating conditions for the hysteresis transition
Measurements of the Drag Coefficient of Simulated Micrometeoroids
DeLuca, M.; Munsat, T.; Sternovsky, Z.
2017-12-01
The dust accelerator facility operated at the University of Colorado is used to simulate meteoric ablation, including measuring the ionization efficiency over a wide range of velocities (e.g., DeLuca et al., Planet. Space Sci., submitted, 2017). This presentation reports on the most recent experimental measurements of the drag coefficient that determines the particles' slowdown from their frictional interaction with the atmosphere. The measurements indicate that meteors experience considerably more slowdown than usually assumed. The simulated meteors consisted of submicron sized aluminum particles shot into an air chamber held at 200 mTorr pressure at velocities between 1 - 10 km/s using the dust accelerator and meteor ablation facility. The slowdown is calculated from precise timing measurements made using pickup tube detectors placed upstream and near the entrance to the air chamber, and an impact detector inside the air chamber at the downstream end of the chamber. Supporting modeling calculations show that the particles have little or no mass loss during their interaction with air and thus constant radius can be assumed. Preliminary results for the drag coefficient calculated from these timing measurements reveal that the aluminum particles have a drag coefficient of 1.51 ± 0.24 in air, which is higher than typically assumed in meteoric ablation models (usually 0.5 to 1), indicating that meteors may experience more air drag than previously assumed. More detailed measurements over a wider parameter range are underway.
Study of the determination method of the river dispersion coefficient
International Nuclear Information System (INIS)
Carvalho, M.A.G. de.
1982-01-01
An application of the method introduced by 'Fischer, H.B. - 1968 - Dispersion prediction in natural streams Journal of the Sanitary Engineering Division, ACSE, vol. 94 n 5A5. Proc. Paper 6169 pp 927-943.', for the calculation of the dispersion coefficient, based on Taylor's model is made. The aim is to develop a method which avoids the necessity of having an instantaneous impulse at the entrance section (1st section) of the system being measured. The dispersion coefficient is determined by curve fitting the experimental response in the 2nd secton and that obtained with the model by means of the non-linear least-squares method. The same method is applied with the residence time distribution function. The theoretical differences between these two function and their results are discussed. By adjusting the two model parameters in all these calculations, the dispersion coefficient and the mean velocity are determined, simultaneously. A comparison between the moment's method and Fischer's formulation is also done using the same experimental data. (E.G.) [pt
Conformal anomaly c-coefficients of superconformal 6d theories
Energy Technology Data Exchange (ETDEWEB)
Beccaria, Matteo [Dipartimento di Matematica e Fisica Ennio De Giorgi, Università del Salento & INFN,Via Arnesano, 73100 Lecce (Italy); Tseytlin, Arkady A. [The Blackett Laboratory, Imperial College,London SW7 2AZ (United Kingdom)
2016-01-04
We propose general relations between the conformal anomaly and the chiral (R-symmetry and gravitational) anomaly coefficients in 6d (1,0) superconformal theories. The suggested expressions for the three type B conformal anomaly c{sub i}-coefficients complement the expression for the type A anomaly a-coefficient found in http://arxiv.org/abs/1506.03807. We check them on several examples — the standard (1,0) hyper and tensor multiplets as well as some higher derivative short multiplets containing vector fields that generalize the superconformal 6d vector multiplet discussed in http://arxiv.org/abs/1506.08727. We also consider a family of higher derivative superconformal (2,0) 6d multiplets associated to 7d multiplets in the KK spectrum of 11d supergravity compactified on S{sup 4}. In particular, we prove that (2,0) 6d conformal supergravity coupled to 26 tensor multiplets is free of all chiral and conformal anomalies. We discuss some interacting (1,0) superconformal theories, predicting the c{sub i}-coefficients for the “E-string” theory on multiple M5-branes at E{sub 8} 9-brane and for the theory describing M5-branes at an orbifold singularity ℂ{sup 2}/Γ. Finally, we elaborate on holographic computation of subleading corrections to conformal anomaly coefficients coming from R{sup 2}+R{sup 3} terms in 7d effective action, revisiting, in particular, the (2,0) theory case.
Effect of hypothermic pulmonary artery flushing on capillary filtration coefficient.
Andrade, R S; Wangensteen, O D; Jo, J K; Tsai, M Y; Bolman, R M
2000-07-27
We previously demonstrated that surfactant dilution and inhibition occur immediately after pulmonary artery flushing with hypothermic modified Euro-Collins solution. Consequently, we speculated that increased capillary permeability contributed to these surfactant changes. To test this hypothesis, we evaluated the effects of hypothermic pulmonary artery flushing on the pulmonary capillary filtration coefficient (Kfc), and additionally performed a biochemical analysis of surfactant. We used a murine isolated, perfused lung model to measure the pulmonary capillary filtration coefficient and hemodynamic parameters, to determine the wet to dry weight ratio, and to evaluate surfactant by biochemical analysis of lung lavage fluid. We defined three study groups. In group I (controls), we harvested lungs without hypothermic pulmonary artery flushing, and measured Kfc immediately. In group II (in situ flush), we harvested lungs after hypothermic pulmonary artery flushing with modified Euro-Collins solution, and then measured Kfc. Experiments in groups I and II were designed to evaluate persistent changes in Kfc after pulmonary artery flushing. In group III (ex vivo flush), we flushed lungs ex vivo to evaluate transient changes in Kfc during hypothermic pulmonary artery flushing. Groups I and II did not differ significantly in capillary filtration coefficient and hemodynamics. Group II showed significant alterations on biochemical surfactant analysis and a significant increase in wet-to-dry weight ratio, when compared with group I. In group III, we observed a significant transient increase in capillary filtration coefficient during pulmonary artery flushing. Hypothermic pulmonary artery flushing transiently increases the capillary filtration coefficient, leads to an increase in the wet to dry weight ratio, and induces biochemical surfactant changes. These findings could be explained by the effects of hypothermic modified Euro-Collins solution on pulmonary capillary
Confidence bounds and hypothesis tests for normal distribution coefficients of variation
Steve Verrill; Richard A. Johnson
2007-01-01
For normally distributed populations, we obtain confidence bounds on a ratio of two coefficients of variation, provide a test for the equality of k coefficients of variation, and provide confidence bounds on a coefficient of variation shared by k populations.
International Nuclear Information System (INIS)
Furuta, Hiroshi; Yamamoto, Ichiro
1996-01-01
Diffusion coefficients in 4-component mixture D ij (4) were expressed explicitly in terms of binary diffusion coefficients and mole fractions by solving a ratio of determinants defined by Hirschfelder et al. The explicit expressions of D ij (4) were divided into two terms, a term due to the i-j pairs of attention and a term common to all the pairs out of the 4 components. The two terms of D ij (4) had extended structures similar to corresponding those of D ij (3) respectively. (author)
Effect of electrostatic field on dynamic friction coefficient of pistachio
Directory of Open Access Journals (Sweden)
M. H Aghkhani
2016-04-01
Full Text Available Introduction: Separation and grading of agricultural products from the production to supply, has notable importance. The separation can be done based on physical, electrical, magnetic, optical properties and etc. It is necessary for any development of new systems to study enough on the properties and behavior of agricultural products. Some characteristics for separation are size (length, width and thickness, hardness, shape, density, surface roughness, color, speed limit, aerodynamic properties, electrical conductivity, elasticity and coefficient of static friction point. So far, the friction properties of agricultural products used in the separating process, but the effect of electrostatic charging on static and dynamic coefficients of friction for separation had little attention. The aim of this study was to find out the interactions between electrostatic and friction properties to find a way to separate products that separation is not possible with conventional methods or not sufficiently accurate. In this paper, the separation of close and smiley pistachios by electrostatic charging was investigated. Materials and Methods: Kallehghoochi pistachio cultivar has the top rank in production in Iran. Therefore, it was used as a sample. The experimental design that used in this study, had moisture content at three levels (24.2, 14.5 and 8.1 percent, electric field intensity at three levels (zero, 4000 and 7000 V, speed of movement on the surface at three levels (1300, 2500 and 3300 mm per minute, friction surface (galvanized sheet iron, aluminum and flat rubber and pistachio type at two levels (filled splits and closed that was measured and analyzed in completely randomized factorial design. A friction measuring device (built in Ferdowsi University of Mashhad used to measure the friction force. It has a removable table that can move in two directions with adjustable speed. The test sample put into the vessel with internal dimensions of 300 × 150
Leone, Stephen R.
1995-01-01
The objectives of the research are to measure low temperature laboratory rate coefficients for key reactions relevant to the atmospheres of Titan and Saturn. These reactions are, for example, C2H + H2, CH4, C2H2, and other hydrocarbons which need to be measured at low temperatures, down to approximately 150 K. The results of this work are provided to NASA specialists who study modeling of the hydrocarbon chemistry of the outer planets. The apparatus for this work consists of a pulsed laser photolysis system and a tunable F-center probe laser to monitor the disappearance of C2H. A low temperature cell with a cryogenic circulating fluid in the outer jacket provides the gas handling system for this work. These elements have been described in detail in previous reports. Several new results are completed and the publications are just being prepared. The reaction of C2H with C2H2 has been measured with an improved apparatus down to 154 K. An Arrhenius plot indicates a clear increase in the rate coefficient at the lowest temperatures, most likely because of the long-lived (C4H3) intermediate. The capability to achieve the lowest temperatures in this work was made possible by construction of a new cell and addition of a multipass arrangement for the probe laser, as well as improvements to the laser system.
Someswara Rao, Chinta; Viswanadha Raju, S
2016-03-01
In this paper, we consider correlation coefficient, rank correlation coefficient and cosine similarity measures for evaluating similarity between Homo sapiens and monkeys. We used DNA chromosomes of genome wide genes to determine the correlation between the chromosomal content and evolutionary relationship. The similarity among the H. sapiens and monkeys is measured for a total of 210 chromosomes related to 10 species. The similarity measures of these different species show the relationship between the H. sapiens and monkey. This similarity will be helpful at theft identification, maternity identification, disease identification, etc.