Kinetics of coal liquefaction during heating-up and isothermal stages

Energy Technology Data Exchange (ETDEWEB)

Xian Li; Haoquan Hu; Shengwei Zhu; Shuxun Hu; Bo Wu; Meng Meng [Dalian University of Technology, Dalian (China). Institute of Coal Chemical Engineering

2008-04-15

Direct liquefaction of Shenhua bituminous coal was carried out in a 500 ml autoclave with iron catalyst and coal liquefaction cycle-oil as solvent at initial hydrogen of 8.0 MPa, residence time of 0-90 min. To investigate the liquefaction kinetics, a model for heating-up and isothermal stages was developed to estimate the rate constants of both stages. In the model, the coal was divided into three parts, easy reactive part, hard reactive part and unreactive part, and four kinetic constants were used to describe the reaction mechanism. The results showed that the model is valid for both heating-up and isothermal stages of liquefaction perfectly. The rate-controlled process for coal liquefaction is the reaction of preasphaltene plus asphaltene (PAA) to oil plus gas (O + G). The upper-limiting conversion of isothermal stage was estimated by the kinetic calculation. 21 refs., 4 figs., 4 tabs.

Isochronal and isothermal crystallization kinetics of amorphous Fe-based alloys

Energy Technology Data Exchange (ETDEWEB)

Zhang, J.T. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Wang, W.M., E-mail: weiminw@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Ma, H.J.; Li, G.H.; Li, R.; Zhang, Z.H. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

2010-06-10

Using the differential scanning calorimetry (DSC), the isochronal and isothermal crystallization kinetics of amorphous Fe{sub 61}Co{sub 9-x}Zr{sub 8}Mo{sub 5}W{sub x}B{sub 17} (x = 0 and 2) ribbons was investigated by the Kissinger equation and by the Kolmogorov-Johnson-Mehl-Avrami and Ranganathan-Heimendahl equations, respectively. The results show that tungsten can improve the activation energy E{sub 1}{sup K} for the first crystallization in the isochronal annealing process and activation energy E{sub n} for the nucleation in the isothermal annealing process, which can be ascribed to the dissolution of tungsten in the amorphous phase. Meanwhile, tungsten can decrease the activation energy E{sub 2}{sup K} for the second crystallization in the isochronal annealing process and growth activation energy E{sub g} in the isothermal annealing process, which is possibly associated with the formation of W-rich compound after the early nucleation process.

Study on the isothermal forging process of MB26 magnesium alloy adaptor

Directory of Open Access Journals (Sweden)

Xu Wenchen

2015-01-01

Full Text Available The isothermal forging process is an effective method to manufacture complex-shaped components of hard-to-work materials, such as magnesium alloys. This study investigates the isothermal forging process of an MB26 magnesium alloy adaptor with three branches. The results show that two-step forging process is appropriate to form the adaptor forging, which not only improves the filling quality but also reduces the forging load compared with one-step forging process. Moreover, the flow line is distributed along the contour of the complex-shaped adaptor forging.

Phase field modeling of dendritic coarsening during isothermal

Directory of Open Access Journals (Sweden)

Zhang Yutuo

2011-08-01

Full Text Available Dendritic coarsening in Al-2mol%Si alloy during isothermal solidification at 880K was investigated by phase field modeling. Three coarsening mechanisms operate in the alloy: (a melting of small dendrite arms; (b coalescence of dendrites near the tips leading to the entrapment of liquid droplets; (c smoothing of dendrites. Dendrite melting is found to be dominant in the stage of dendritic growth, whereas coalescence of dendrites and smoothing of dendrites are dominant during isothermal holding. The simulated results provide a better understanding of dendrite coarsening during isothermal solidification.

Sorption Isotherm of Southern Yellow Pine—High Density Polyethylene Composites

Directory of Open Access Journals (Sweden)

Feihong Liu

2015-01-01

Full Text Available Temperature and relative humidity (RH are two major external factors, which affect equilibrium moisture content (EMC of wood-plastic composites (WPCs. In this study, the effect of different durability treatments on sorption and desorption isotherms of southern yellow pine (SYP-high density polyethylene (HDPE composites was investigated. All samples were equilibriumed at 20 °C and various RHs including 16%, 33%, 45%, 66%, 75%, 85%, 93%, and100%. EMCs obtained from desorption and absorption for different WPC samples were compared with Nelson’s sorption isotherm model predictions using the same temperature and humidity conditions. The results indicated that the amount of moisture absorbed increased with the increases in RH at 20 °C. All samples showed sorption hysteresis at a fixed RH. Small difference between EMC data of WPC samples containing different amount of ultraviolet (UV stabilizers were observed. Similar results were observed among the samples containing different amount of zinc borate (ZB. The experimental data of EMCs at various RHs fit to the Nelson’s sorption isotherm model well. The Nelson’s model can be used to predicate EMCs of WPCs under different RH environmental conditions.

Improved Isotherm Data for Adsorption of Methane on Activated Carbons

KAUST Repository

Loh, Wai Soong

2010-08-12

This article presents the adsorption isotherms of methane onto two different types of activated carbons, namely, Maxsorb III and ACF (A-20) at temperatures from (5 to 75) °C and pressures up to 2.5 MPa. The volumetric technique has been employed to measure the adsorption isotherms. The experimental results presented herein demonstrate the improved accuracy of the uptake values compared with previous measurement techniques for similar adsorbate-adsorbent combinations. The results are analyzed with various adsorption isotherm models. The heat of adsorption, which is concentration and temperature dependent, has been calculated from the measured isotherm data. Henry\\'s law coefficients for these adsorbent-methane pairs are also evaluated at various temperatures. © 2010 American Chemical Society.

Simulation and scaling for natural convection flow in a cavity with isothermal boundaries

International Nuclear Information System (INIS)

Jiracheewanun, S.; Armfield, S.W.; McBain, G.D.; Behnia, M.

2005-01-01

A numerical study of the transient two-dimensional natural convection flow within a differentially heated square cavity with iso-flux side walls and adiabatic top and bottom boundaries is presented. The governing equations are discretized using a non-staggered mesh and solved using a non-iterative fractional-step pressure correction method which provides second-order accuracy in both time and space. Results are obtained with the iso-flux boundary condition for Ra = 5.8 x 10 9 and Pr = 7.5. The results show that the transient flow features obtained for the iso-flux cavity are similar to the flow features for the isothermal case. However, the fully developed flow features of the iso-flux cavity are very different from the isothermal case. The scalings for the fully developed iso-flux boundary condition flow have been found to be different to those of the isothermal boundary condition flow. (authors)

Isothermal Martensite Formation

DEFF Research Database (Denmark)

Villa, Matteo

Isothermal (i.e. time dependent) martensite formation in steel was first observed in the 40ies of the XXth century and is still treated as an anomaly in the description of martensite formation which is considered as a-thermal (i.e. independent of time). Recently, the clarification of the mechanism...... of lattice strains provided fundamental information on the state of stress in the material and clarified the role of the strain energy on martensite formation. Electron backscatter diffraction revealed that the microstructure of the material and the morphology of martensite were independent on the cooling...... leading to isothermal kinetics acquired new practical relevance because of the identification of isothermal martensite formation as the most likely process responsible for enhanced performances of sub-zero Celsius treated high carbon steel products. In the present work, different iron based alloys...

Financial Statement Audit Report of Isothermal Community College.

Science.gov (United States)

Campbell, Ralph

This report presents the results of the Isothermal Community College financial statement audit for the fiscal year ending on June 30, 1998. Isothermal Community College is a component of the State of North Carolina, thus the authority to audit is granted by Article 5A of G.S. 147. The accounts and operations of the institution were subject to…

Kinetic and isotherm studies of Cu(II) biosorption onto valonia tannin resin

Energy Technology Data Exchange (ETDEWEB)

Sengil, I. Ayhan [Department of Environmental Engineering, Engineering Faculty, Sakarya University, 54100 Sakarya (Turkey)], E-mail: asengil@sakarya.edu.tr; Ozacar, Mahmut [Department of Chemistry, Science and Arts Faculty, Sakarya University, 54100 Sakarya (Turkey); Tuerkmenler, Harun [Institute of Sciences and Technology, Sakarya University, 54040 Sakarya (Turkey)

2009-03-15

The biosorption of Cu(II) from aqueous solutions by valonia tannin resin was investigated as a function of particle size, initial pH, contact time and initial metal ion concentration. The aim of this study was to understand the mechanisms that govern copper removal and find a suitable equilibrium isotherm and kinetic model for the copper removal in a batch reactor. The experimental isotherm data were analysed using the Langmuir, Freundlich and Temkin equations. The equilibrium data fit well in the Langmuir isotherm. The experimental data were analysed using four sorption kinetic models - the pseudo-first- and second-order equations, the Elovich and the intraparticle diffusion model equation - to determine the best fit equation for the biosorption of copper ions onto valonia tannin resin. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process, whereas the Elovich equation also fits the experimental data well.

Determination of the kinetic parameters of Be O using isothermal decay method

Energy Technology Data Exchange (ETDEWEB)

Azorin N, J.; Torijano C, E. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Azorin V, C.; Rivera M, T., E-mail: azorin@xanum.uam.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

2015-10-15

Full text: Most of the existing methods for obtaining the frequency factors make use of the trap depth (activation energy) making some assumptions about the order of the kinetics. This causes inconsistencies in the reported values of trapping parameters due that the values of the activation energy obtained by different methods differ appreciably among them. Then, it is necessary to use a method independent of the trap depth making use of the isothermal luminescence decay method. The trapping parameters associated with the prominent glow peak of Be O (280 degrees C) are reported using isothermal luminescence decay method. As a check, the trap parameters are also calculated by glow curve shape (Chen s) method after isolating the prominent glow peak by thermal cleaning technique. Our results show a very good agreement between the trapping parameters calculated by the two methods. Isothermal luminescence decay method was used for determining the trapping parameters of Be O. Results obtained applying this method are in good agreement with those obtained using other methods, except in the value of the frequency factor. (Author)

Adsorption isotherms of pear at several temperatures

OpenAIRE

Mitrevski Vangelče; Lutovska Monika; Mijakovski Vladimir; Pavkov Ivan S.; Babić Mirko M.; Radojčin Milivoje T.

2015-01-01

The moisture adsorption isotherms of pear were determined at 15ºC, 30ºC and 45ºC using the standard static gravimetric method over a range of water activity from 0.112 to 0.920. The experimental data were fitted with isotherm equations recommended in ASAE Standard D245.5. In order to find which equation gives the best results, large number of numerical experiments were performed. After that, several statistical criteria proposed in scientific literature for...

(AJST) ADSORPTION ISOTHERME DE L'ACIDE ACÉTIQUE PAR ...

African Journals Online (AJOL)

opiyo

ont été étudiées à partir des isothermes d'adsorption de l'acide acétique à 30° et ... has resulted in the determination of the two types of adsorption isotherms : the Freundlich and .... zinc 60 % pendant 6 heures n'améliore pas suffisamment le.

Suitability of adsorption isotherms for predicting the retention capacity of active slag filters removing phosphorus from wastewater.

Science.gov (United States)

Pratt, C; Shilton, A

2009-01-01

Active slag filters are an emerging technology for removing phosphorus (P) from wastewater. A number of researchers have suggested that adsorption isotherms are a useful tool for predicting P retention capacity. However, to date the appropriateness of using isotherms for slag filter design remains unverified due to the absence of benchmark data from a full-scale, field filter operated to exhaustion. This investigation compared the isotherm-predicted P retention capacity of a melter slag with the P adsorption capacity determined from a full-scale, melter slag filter which had reached exhaustion after five years of successfully removing P from waste stabilization pond effluent. Results from the standard laboratory batch test showed that P adsorption correlated more strongly with the Freundlich Isotherm (R(2)=0.97, Pretention capacity of 0.014 gP/kg slag; markedly lower than the 1.23 gP/kg slag adsorbed by the field filter. Clearly, the result generated by the isotherm bears no resemblance to actual field capacity. Scanning electron microscopy analysis revealed porous, reactive secondary minerals on the slag granule surfaces from the field filter which were likely created by weathering. This slow weathering effect, which generates substantial new adsorption sites, is not accounted for by adsorption isotherms rendering them ineffective in slag filter design.

Room temperature isotherms for Mo and Ni

International Nuclear Information System (INIS)

Masse, J.L.

1986-11-01

Isotherms at room temperature for Mo and Ni are proposed. They are of three types: BIRCH, KEANE and BORN-MIE. The adjustable constants appearing in these isotherms have been determined from experimental quantities at zero pressure. An evaluation of the limit of (δB T /δP) T as P #-> # ∞, where B T is the isothermal bulk modulus, has been also used. These three isotherms obtained for Mo and Ni are compared with isotherms derived from shock-wave data according to the PRIETO's model. There is a good agreement between these and these derived from shock-wave data. The three isotherms proposed for Mo and Ni can be considered as valid until pressures of several B To , where B To is the bulk modulus B T at P = o [fr

Isothermal and non-isothermal cure of a tri-functional epoxy resin (TGAP): a stochastic TMDSC study

OpenAIRE

Hutchinson, John M.; Shiravand, Fatemeh; Calventus Solé, Yolanda; Fraga Rivas, Iria

2012-01-01

The isothermal cure of a highly reactive tri-functional epoxy resin, tri-glycidyl para-amino phenol (TGAP), with diamino diphenyl sulphone (DDS), at two different cure temperatures Tc has been studied by both conventional differential scanning calorimetry (DSC) and by a stochastic temperature modulated DSC technique, TOPEM. From a series of isothermal cure experiments for increasing cure times, the glass transition temperature Tg as a function of isothermal cure time is determined by co...

DuPont IsoTherming clean fuel technology

Energy Technology Data Exchange (ETDEWEB)

Levinski, E. [E.I. DuPont Co., Wilmington, DE (United States)

2009-07-01

This poster described a hydroprocessing technology that DuPont has acquired from Process Dynamics, Inc. The IsoTherming clean fuel technology significantly reduces sulphur in motor fuels. The technology provides petroleum refiners the solution for meeting ultra low sulphur diesel requirements, at much lower costs than conventional technologies. IsoTherming hydroprocessing operates in a kinetically limited mode, with no mass transfer limitation. Hydrogen is delivered to the reactor in the liquid phase as soluble hydrogen, allowing for much higher space velocities than conventional hydrotreating reactors. Treated diesel is recycled back to the inlet of the reactor, generating less heat and more hydrogen into the reactor. The process results in a more isothermal reactor operation that allows for better yields, fewer light ends and greater catalyst life. The technology reduces coking, because the process provides enough hydrogen in the solution when cracking reactions take place. As a result, the process yields longer catalyst life. Other advantages for refiners include lower total investment; reduced equipment delivery lead times; reduced maintenance and operating costs; and configuration flexibility. tabs., figs.

The oxidation kinetics of zircaloy - 4 under isothermal conditions

International Nuclear Information System (INIS)

Santos, A.M.M. dos; Cardoso, P.E.

1982-01-01

The oxidation kinetics of zircaloy-4 tubes was studied by means of isothermal tests in the temperature interval 500 0 C to 900 0 C. Dry oxygen and water steam, were used as oxidant agents. The results show that the oxidation kinetics law exhibits a behaviour from cubic to parabolic in the range of the time and temperatures of the experiment. Dry oxygen shows a stronger oxidation effect than water steam. A special mechanical test to study the embrittlement effect in the small samples of zircaloy tubes was used. (Author) [pt

Total Correlation Function Integrals and Isothermal Compressibilities from Molecular Simulations

DEFF Research Database (Denmark)

Wedberg, Rasmus; Peters, Günther H.j.; Abildskov, Jens

2008-01-01

Generation of thermodynamic data, here compressed liquid density and isothermal compressibility data, using molecular dynamics simulations is investigated. Five normal alkane systems are simulated at three different state points. We compare two main approaches to isothermal compressibilities: (1...... in approximately the same amount of time. This suggests that computation of total correlation function integrals is a route to isothermal compressibility, as accurate and fast as well-established benchmark techniques. A crucial step is the integration of the radial distribution function. To obtain sensible results...

Evaluation of theoretical and empirical water vapor sorption isotherm models for soils

Science.gov (United States)

Arthur, Emmanuel; Tuller, Markus; Moldrup, Per; de Jonge, Lis W.

2016-01-01

The mathematical characterization of water vapor sorption isotherms of soils is crucial for modeling processes such as volatilization of pesticides and diffusive and convective water vapor transport. Although numerous physically based and empirical models were previously proposed to describe sorption isotherms of building materials, food, and other industrial products, knowledge about the applicability of these functions for soils is noticeably lacking. We present an evaluation of nine models for characterizing adsorption/desorption isotherms for a water activity range from 0.03 to 0.93 based on measured data of 207 soils with widely varying textures, organic carbon contents, and clay mineralogy. In addition, the potential applicability of the models for prediction of sorption isotherms from known clay content was investigated. While in general, all investigated models described measured adsorption and desorption isotherms reasonably well, distinct differences were observed between physical and empirical models and due to the different degrees of freedom of the model equations. There were also considerable differences in model performance for adsorption and desorption data. While regression analysis relating model parameters and clay content and subsequent model application for prediction of measured isotherms showed promise for the majority of investigated soils, for soils with distinct kaolinitic and smectitic clay mineralogy predicted isotherms did not closely match the measurements.

Desorption isotherms of heavy (AZOBE, EBONY) and light heavyweight tropical woods (IROKO, SAPELLI) of Cameroon

Science.gov (United States)

Nsouandélé, J. L.; Tamba, J. G.; Bonoma, B.

2018-04-01

This work is centered on the study of the desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods, which contribute in the determination of drying and storage of tropical plank woods. Desorption isotherms of tropical woods were experimentally determined under different temperatures in this study using the gravimetric method. The determination of Henderson's model isotherms parameters of desorption were obtained for temperatures of 20 °C, 30 °C, 40 °C, and 50 °C. The mean relative deviation between theoretical and experimental moisture contents was calculated and fitted well with the desorption models of tropical woods. We noticed that Henderson models fitted much better with experimental ones for 95% of relative humidity. The sigmoid shapes of results are satisfactory. Hysteresis phenomenon was observed for desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods. Results showed the difference between the stability and use of heavy and heavyweight tropical wood. These results help in the estimation of water content at equilibrium of tropical woods in relative humidity from experimented ones. Hygroscopic equilibrium humidity of heavy tropical woods varied between 0% and 50% while those of heavyweight varied between 0% and 25%. Therefore, these woods can be used in an opened environment; woodwork and decoration.

High Nitrogen Austenitic Stainless Steel Precipitation During Isothermal Annealing

OpenAIRE

Maria Domankova; Katarína Bártová; Ivan Slatkovský; Peter Pinke

2016-01-01

The time-temperature-precipitation in high-nitrogen austenitic stainless steel was investigated using light optical microscopy, transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The isothermal precipitation kinetics curves and the corresponding precipitation activation energy were obtained. The diffusion activation energy of M2N precipitation is 129 kJ/mol. The results show that critical temperature for M2N precipitation is about 825°C with ...

Production of valuable pyrolytic oils from mixed Municipal Solid Waste (MSW in Indonesia using non-isothermal and isothermal experimental

Directory of Open Access Journals (Sweden)

Indra Mamad Gandidi

2017-09-01

Full Text Available Municipal solid waste (MSW, disposed of at open dumping sites, poses health risks, contaminates surface water, and releases greenhouse gasses such as methane. However, pyrolysis offers the opportunity to convert MSW into Bio-Oil (BO for clean energy resource. In this paper, an MSW sample consisting of plastic, paper and cardboard, rubber and textiles, and vegetable waste is pyrolysed on a laboratory scale in a fixed-bed vacuum reactor. In the non-isothermal process, the sample was fed into the reactor and then heated. In the isothermal process, the reactor is first heated and then the sample is added. The non-isothermal process created greater BO in both quality and quantity. The BO had a larger amount of gasoline species than diesel-48 fuel, with at 33.44%the BO produced by isothermal pyrolysis and 36.42% in non-isothermal pyrolysis. However the product of isothermal pyrolysis had a higher acid content that reduced its heating value.

Adsorption of 4-chlorophenol from aqueous solutions by xad-4 resin: Isotherm, kinetic, and thermodynamic analysis

International Nuclear Information System (INIS)

Bilgili, M. Sinan

2006-01-01

Removal of 4-chlorophenol (4-CP) from synthetic aqueous solutions through adsorption on Amberlite XAD-4 resin, a non-ionic macroreticular resins, under batch equilibrium experimental conditions at 298, 308 and 318 K was investigated. It is necessary to propose a suitable model to a better understanding on the mechanism of 4-CP adsorption. For this purpose, Langmiur, Freundlich, Toth, and Redlich-Peterson (RP) isotherm models were compared. The two and three parameters in the adopted adsorption isotherm models were determined by the help of MATLAB package program. It was determined that best fitted adsorption isotherm models were obtained to be in the order: Redlich-Peterson > Langmuir > Toth > Freundlich isotherms. The pseudo-second-order kinetic model provided the best correlation to the experimental results. Results of the intra-particle diffusion model show that the pore diffusion is not the only rate limiting step. The lower correlation of the data to the Bangham's equation also represents that the diffusion of the adsorbate into pores of the sorbent is not the only rate-controlling step. The thermodynamic constants of adsorption phenomena; ΔG o , ΔH o , and ΔS o were found as -4.17 (at 298 K) kJ/mol, -42.01 kJ/mol, and -0.127 kJ/(mol K), respectively. The results showed that adsorption of 4-CP on Amberlite XAD-4, a nonionic polymeric resin was exothermic and spontaneous

A Model of the Effect of the Microbial Biomass on the Isotherm of the Fermenting Solids in Solid-State Fermentation

Directory of Open Access Journals (Sweden)

Barbara Celuppi Marques

2006-01-01

Full Text Available We compare isotherms for soybeans and soybeans fermented with Rhizopus oryzae, showing that in solid-state fermentation the biomass affects the isotherm of the fermenting solids. Equations are developed to calculate, for a given overall water content of the fermenting solids, the water contents of the biomass and residual substrate, as well as the water activity. A case study, undertaken using a mathematical model of a well-mixed bioreactor, shows that if water additions are made on the basis of the assumption that fermenting solids have the same isotherm as the substrate itself, poor growth can result since the added water does not maintain the water activity at levels favorable for growth. We conclude that the effect of the microbial biomass on the isotherm of the fermenting solids must be taken into account in mathematical models of solid-state fermentation bioreactors.

Non-isothermal Crystallization, Thermal Stability, and Mechanical Performance of Poly(L-lactic acid/Barium Phenylphosphonate Systems

Directory of Open Access Journals (Sweden)

Cai Yan-Hua

2017-11-01

Full Text Available The introduction of a nucleating agent in semi-crystalline polymers is a frequently utilized way to improve the crystallization performance, and the use of a nucleating agent has a very great effect on the performance of the polymer in other areas including thermal stability and mechanical properties. In this investigation, barium phenylphosphonate (BaP was prepared as a crystallization accelerator for Poly(L-lactic acid (PLLA, and the non-isothermal crystallization behavior, thermal stability, and mechanical properties of PLLA modified by BaP were investigated using differential scanning calorimetry (DSC, X-ray diffraction (XRD, thermogravimetric analysis (TGA, and electronic tensile testing. Non-isothermal crystallization analysis showed that the BaP could significantly accelerate the crystallization of PLLA, and the non-isothermal crystallization peak shifted to a higher temperature with increasing concentration of BaP, however, the corresponding crystallization peak became wider. XRD results after non-isothermal crystallization confirmed the non-isothermal crystallization DSC results. Additionally, the addition of BaP did not change the crystal form of PLLA. A comparative study on thermal stability indicated that BaP decreased the onset decomposition temperature of PLLA, resulting from the formation of more tiny and imperfect crystals. Whereas the influence of BaP on the thermal decomposition profile of PLLA was negligible. In terms of mechanical properties, the tensile strength and elastic modulus of PLLA/BaP increased compared to the virgin PLLA, unfortunately, the elongation at break decreased.

Detection of genetically modified organisms (GMOs using isothermal amplification of target DNA sequences

Directory of Open Access Journals (Sweden)

La Mura Maurizio

2009-02-01

Full Text Available Abstract Background The most common method of GMO detection is based upon the amplification of GMO-specific DNA amplicons using the polymerase chain reaction (PCR. Here we have applied the loop-mediated isothermal amplification (LAMP method to amplify GMO-related DNA sequences, 'internal' commonly-used motifs for controlling transgene expression and event-specific (plant-transgene junctions. Results We have tested the specificity and sensitivity of the technique for use in GMO studies. Results show that detection of 0.01% GMO in equivalent background DNA was possible and dilutions of template suggest that detection from single copies of the template may be possible using LAMP. Conclusion This work shows that GMO detection can be carried out using LAMP for routine screening as well as for specific events detection. Moreover, the sensitivity and ability to amplify targets, even with a high background of DNA, here demonstrated, highlights the advantages of this isothermal amplification when applied for GMO detection.

Limitations of sorption isotherms on modeling groundwater contaminant transport

International Nuclear Information System (INIS)

Silva, Eduardo Figueira da

2007-01-01

Design and safety assessment of radioactive waste repositories, as well as remediation of radionuclide contaminated groundwater require the development of models capable of accurately predicting trace element fate and transport. Adsorption of trace radionuclides onto soils and groundwater is an important mechanism controlling near- and far- field transport. Although surface complexation models (SCMs) can better describe the adsorption mechanisms of most radionuclides onto mineral surfaces by directly accounting for variability of system properties and mineral surface properties, isotherms are still used to model contaminant transport in groundwater, despite the much higher system dependence. The present work investigates differences between transport model results based on these two approaches for adsorption modeling. A finite element transport model is used for the isotherm model, whereas the computer program PHREEQC is used for the SCM approach. Both models are calibrated for a batch experiment, and one-dimensional transport is simulated using the calibrated parameters. At the lower injected concentrations there are large discrepancies between SCM and isotherm transport predictions, with the SCM presenting much longer tails on the breakthrough curves. Isotherms may also provide non-conservative results for time to breakthrough and for maximum concentration in a contamination plume. Isotherm models are shown not to be robust enough to predict transport behavior of some trace elements, thus discouraging their use. The results also illustrate the promise of the SCM modeling approach in safety assessment and environmental remediation applications, also suggesting that independent batch sorption measurements can be used, within the framework of the SCM, to produce a more versatile and realistic groundwater transport model for radionuclides which is capable of accounting more accurately for temporal and spatial variations in geochemical conditions. (author)

Analysis of isothermal sintering of zinc-titanate doped with MgO

Directory of Open Access Journals (Sweden)

Obradović N.

2007-01-01

Full Text Available The aim of this work was analysis of isothermal sintering of zinc titanate ceramics doped with MgO obtained by mechanical activation. Mixtures of ZnO, TiO2 and MgO (0, 1.25 and 2.5% were mechanically activated 15 minutes in a planetary ball mill. The powders obtained were pressed under different pressures and the results were fitted with a phenomenological compacting equation. Isothermal sintering was performed in air for 120 minutes at four different temperatures. Structural characterization of ZnO-TiO2-MgO system after milling was performed at room temperature using XRPD measurements. DTA measurements showed different activation energies for pure and doped ZnO-TiO2 systems. Thus addition of MgO stabilizes the crystal structure of zinc titanate.

[Application of classical isothermal adsorption models in heavy metal ions/ diatomite system and related problems].

Science.gov (United States)

Zhu, Jian; Wu, Qing-Ding; Wang, Ping; Li, Ke-Lin; Lei, Ming-Jing; Zhang, Wei-Li

2013-11-01

In order to fully understand adsorption nature of Cu2+, Zn2+, Pb2+, Cd2+, Mn2+, Fe3+ onto natural diatomite, and to find problems of classical isothermal adsorption models' application in liquid/solid system, a series of isothermal adsorption tests were conducted. As results indicate, the most suitable isotherm models for describing adsorption of Pb2+, Cd2+, Cu2+, Zn2+, Mn2+, Fe3+ onto natural diatomite are Tenkin, Tenkin, Langmuir, Tenkin, Freundlich and Freundlich, respectively, the adsorption of each ion onto natural diatomite is mainly a physical process, and the adsorption reaction is favorable. It also can be found that, when using classical isothermal adsorption models to fit the experimental data in liquid/solid system, the equilibrium adsorption amount q(e) is not a single function of ion equilibrium concentration c(e), while is a function of two variables, namely c(e) and the adsorbent concentration W0, q(e) only depends on c(e)/W(0). Results also show that the classical isothermal adsorption models have a significant adsorbent effect, and their parameter values are unstable, the simulation values of parameter differ greatly from the measured values, which is unhelpful for practical use. The tests prove that four-adsorption-components model can be used for describing adsorption behavior of single ion in nature diatomite-liquid system, its parameters k and q(m) have constant values, which is favorable for practical quantitative calculation in a given system.

Isothermal martensitic transformation as an internal-stress-increasing process

International Nuclear Information System (INIS)

Liu, Y.; Xie, Z.L.; Haenninen, H.; Humbeeck, J. van; Pietikaeinen, J.

1995-01-01

Based on the results that the magnitude of the stabilization of retained austenite increases with increasing the amount of martensite transformed, it has been assumed that the martensitic transformation is accompanied with an increase in internal resisting stress which subsequently results in the stabilization of retained austenite. By simplifying this internal resisting stress to be a type of hydrostatic compressive stress acting on retained austenite due to surrounding martensite plates, a thermodynamical analysis for an isothermal martensitic transformation under applied hydrostatic pressure has been performed. The calculated results, to some extent, show a good agreement with the experimental data. (orig.)

Nonequilibrium steady state of biochemical cycle kinetics under non-isothermal conditions

Science.gov (United States)

Jin, Xiao; Ge, Hao

2018-04-01

The nonequilibrium steady state of isothermal biochemical cycle kinetics has been extensively studied, but that under non-isothermal conditions has been much less extensively investigated. When the heat exchange between subsystems is slow, the isothermal assumption of the whole system breaks down, as is true for many types of living organisms. Here, starting with a four-state model of molecular transporter across the cell membrane, we generalize the nonequilibrium steady-state theory of isothermal biochemical cycle kinetics to the circumstances with non-uniform temperatures of subsystems in terms of general master equation models. We obtain a new thermodynamic relationship between the chemical reaction rates and thermodynamic potentials in non-isothermal circumstances, based on the overdamped dynamics along the continuous reaction coordinate. We show that the entropy production can vary up to 3% in real cells, even when the temperature difference across the cell membrane is only approximately 1 K. We then decompose the total thermodynamic driving force into its thermal and chemical components and predict that the net flux of molecules transported by the molecular transporter can potentially go against the temperature gradient in the absence of a chemical driving force. Furthermore, we demonstrate that the simple application of the isothermal transition-state rate formula for each chemical reaction in terms of only the reactant’ temperature is not thermodynamically consistent. Therefore, we mathematically derive several revised reaction rate formulas that are not only consistent with the new thermodynamic relationship but also approximate the exact reaction rate better than Kramers’ rate formula under isothermal conditions.

WATER ADSORPTION AND DESORPTION ISOTHERMS ON MILK POWDER: II. WHOLE MILK

Directory of Open Access Journals (Sweden)

Edgar M. Soteras

2014-03-01

Full Text Available The aim of this research was the determination of adsorption and desorption isotherms of cow whole milk powder. The experiments have been carried out at 15, 25 and 40 ºC, in ranges of moisture and water activity characteristic of normal conditions in which the processes of drying, packaging and storage are developed. By studying the influence of the temperature on the experimental plots, the isosteric adsorption heat was determined. Experimental data were correlated to the referential model of Guggenheim, Anderson and Boer (GAB. For both, adsorption and desorption, a good model fit was observed. The isotherms showed very similar shapes between them and, by comparing adsorption and desorption isotherms, the phenomenon of hysteresis was confirmed.

Multi-model attribution of upper-ocean temperature changes using an isothermal approach

Science.gov (United States)

Weller, Evan; Min, Seung-Ki; Palmer, Matthew D.; Lee, Donghyun; Yim, Bo Young; Yeh, Sang-Wook

2016-06-01

Both air-sea heat exchanges and changes in ocean advection have contributed to observed upper-ocean warming most evident in the late-twentieth century. However, it is predominantly via changes in air-sea heat fluxes that human-induced climate forcings, such as increasing greenhouse gases, and other natural factors such as volcanic aerosols, have influenced global ocean heat content. The present study builds on previous work using two different indicators of upper-ocean temperature changes for the detection of both anthropogenic and natural external climate forcings. Using simulations from phase 5 of the Coupled Model Intercomparison Project, we compare mean temperatures above a fixed isotherm with the more widely adopted approach of using a fixed depth. We present the first multi-model ensemble detection and attribution analysis using the fixed isotherm approach to robustly detect both anthropogenic and natural external influences on upper-ocean temperatures. Although contributions from multidecadal natural variability cannot be fully removed, both the large multi-model ensemble size and properties of the isotherm analysis reduce internal variability of the ocean, resulting in better observation-model comparison of temperature changes since the 1950s. We further show that the high temporal resolution afforded by the isotherm analysis is required to detect natural external influences such as volcanic cooling events in the upper-ocean because the radiative effect of volcanic forcings is short-lived.

A study of the water vapor sorption isotherms of hardened cement pastes: Possible pore structure changes at low relative humidity and the impact of temperature on isotherms

DEFF Research Database (Denmark)

Wu, Min; Johannesson, Björn; Geiker, Mette Rica

2014-01-01

cement paste samples and a model material MCM-41. The pronounced impact of temperature on desorption isotherms of cement based materials as reported in literature was not found in this investigation. The results suggest that the differences between the sorption isotherms measured at different...

Microstructural Evolution and the Precipitation Behavior in X90 Linepipe Steel During Isothermal Processing

Science.gov (United States)

Tian, Y.; Wang, H. T.; Wang, Z. D.; Misra, R. D. K.; Wang, G. D.

2018-03-01

Thermomechanical controlled processing of 560-MPa (X90) linepipe steel was simulated in the laboratory using a thermomechanical simulator to study the microstructural evolution and precipitation behavior during isothermal holding. The results indicated that martensite was obtained when the steels were isothermally held for 5 s at 700 °C. Subsequently, granular bainite and acicular ferrite transformation occurred with increased holding time. Different amount of polygonal ferrite formed after isothermally holding for 600-3600 s. Pearlite nucleated after isothermally holding for 3600 s. Precipitation occurred after isothermal holding for 5 s and continuous precipitation occurred at grain boundaries after isothermally holding for 600 s. After isothermally holding for 3600 s, large Nb/Ti carbide precipitated. The presence of MX-type precipitates was confirmed by diffraction pattern. The interphase precipitation (IP) occurred between 5 and 30 s. Maximum hardness was obtained after isothermally holding for 600 s when IP occurred and rapidly decreased to a low value, mainly because polygonal ferrite dominated the microstructure after isothermally holding for 3600 s.

High Nitrogen Austenitic Stainless Steel Precipitation During Isothermal Annealing

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Maria Domankova

2016-07-01

Full Text Available The time-temperature-precipitation in high-nitrogen austenitic stainless steel was investigated using light optical microscopy, transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The isothermal precipitation kinetics curves and the corresponding precipitation activation energy were obtained. The diffusion activation energy of M2N precipitation is 129 kJ/mol. The results show that critical temperature for M2N precipitation is about 825°C with the corresponding incubation period 2.5 min.

Proton and Copper Binding to Humic Acids Analyzed by XAFS Spectroscopy and Isothermal Titration Calorimetry

NARCIS (Netherlands)

Xu, Jinling; Koopal, Luuk K.; Fang, Linchuan; Xiong, Juan; Tan, Wenfeng

2018-01-01

Proton and copper (Cu) binding to soil and lignite-based humic acid (HA) was investigated by combining X-ray absorption fine structure (XAFS) spectroscopy, isothermal titration calorimetry (ITC), and nonideal-competitive-adsorption (NICA) modeling. NICA model calculations and XAFS results showed

Parametric Study of an Air Charged Franchot Engine with Novel Hot and Cold Isothermalizers

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Jafar M. Daoud

2017-12-01

Full Text Available The Stirling engine is an external combustion engine that uses heat exchangers to enhance the addition and removal of energy. This makes the engine power-dense but expensive, less efficient and complicated. In this contribution, the Stirling engine based on the Franchot engine has novel cylindrical fins working as isothermalizers to improve heat transfer without the complications of heat exchangers. Enhancing the power density by isothermalizing work spaces is compared to the bare cylinder optimized by varying the phase angle. The theoretical analysis shows that both the adiabatic and isothermal fins increase the power and efficiency, achieving the Curzon and Ahlborn efficiency at the maximum power point. In comparison to the phase angle method, the finned engine resulted in much lower gas mass flow rate, which leads to a reduction in the regenerator pumping and enthalpy losses. Thus, the Stirling engine has the potential to be simple, cheap, efficient and power-dense, and thus can be used effectively for different applications.

THERMODYNAMICS AND ADSORPTION ISOTHERMS FOR THE ...

African Journals Online (AJOL)

BAFFA

data were tested using Freundlich and Langmuir adsorption isotherms. The values of the numeric constants ... Keywords: Adsorbate, Adsorbent, Adsorption isotherms, Maize cob, Thermodynamics. INTRODUCTION. Maize (Zea mays) ... several times with water, air – dried and ground to. 850μm particle size and finally kept ...

Isothermal martensite formation at sub-zero temperatures

DEFF Research Database (Denmark)

Stojko, Allan; Hansen, Mikkel Fougt; Slycke, Jan

2010-01-01

austenitized and quenched in oil and thereafter investigated with vibrating sample agnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the subzero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5...... with a continuation of the martensitic transformation. On prolonged isothermal holding a volume reduction was observed for AISI 52100, but not for AISI 1070. A mechanism is proposed that explains the occurrence of isothermal martensite formation....

Isothermal calorimetry on enzymatic biodiesel production

DEFF Research Database (Denmark)

Fjerbæk, Lene

2008-01-01

information about effects taking place when using lipases immobilized on an inert carrier for transesterification of a triglyceride and an alcohol as for biodiesel production. The biodiesel is produced by rapeseed oil and methanol as well as ethanol and a commercial biocatalyst Novozym 435 from Novozymes...... containing a Candida Antarctica B lipase immobilized on an acrylic resin. The reaction investigated is characterized by immiscible liquids (oil, methanol, glycerol and biodiesel) and enzymes imm. on an inert carrier during reaction, which allows several effects to take place that during normal reaction...... conditions can not be elucidated. These effects have been observed with isothermal calorimetry bringing forth new information about the reaction of enzymes catalyzing transesterification. Enzymatic biodiesel production has until now not been investigated with isothermal microcalorimetry, but the results...

Determination of Differential Enthalpy and Isotherm by Adsorption Calorimetry

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V. Garcia-Cuello

2008-01-01

Full Text Available An adsorption microcalorimeter for the simultaneous determination of the differential heat of adsorption and the adsorption isotherm for gas-solid systems are designed, built, and tested. For this purpose, a Calvet heat-conducting microcalorimeter is developed and is connected to a gas volumetric unit built in stainless steel to record adsorption isotherms. The microcalorimeter is electrically calibrated to establish its sensitivity and reproducibility, obtaining K=154.34±0.23 WV−1. The adsorption microcalorimeter is used to obtain adsorption isotherms and the corresponding differential heats for the adsorption of CO2 on a reference solid, such as a NaZSM-5 type zeolite. Results for the behavior of this system are compared with those obtained with commercial equipment and with other studies in the literature.

Microstructure Evolution and the Resulted Influence on Localized Corrosion in Al-Zn-Mg-Cu Alloy during Non-Isothermal Ageing

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Jun-Zhou Chen

2018-05-01

Full Text Available A non-isothermal ageing process was proposed for an Al-Zn-Mg-Cu alloy aiming to accommodate the slow heating/cooling procedure during the ageing of large components. The evolution of microstructure and microchemistry was analyzed by using transmission electron microscopy, high-angle annular dark field imaging, and energy dispersive spectrometry. The age-hardening of the alloy was examined to evaluate the strengthening behavior during the non-isothermal process. The corrosion behavior was investigated via observing the specimens immersed in EXCO solution (solution for Exfoliation Corrosion Susceptibility test in 2xxx and 7xxx series aluminum alloys, referring ASTM G34-01. Secondary precipitation was observed during the cooling stage, leading to increased precipitate number density. The distribution of grain boundary precipitates transits from discontinuous to continuous at the cooling stage, due to the secondary precipitation’s linking-up effect. The solutes’ enrichment on grain boundary precipitates and the depletion in precipitate-free zones develops during the heating procedure, but remains invariable during the cooling procedure. The corrosion in NIA (Non-isothermal Ageing treated specimens initiates from pitting and then transits to intergranular corrosion and exfoliation corrosion. The transition from pitting to intergranular corrosion is very slow for specimens heated to 190 °C, but accelerates slightly as the cooling procedure proceeds. The transition to exfoliation corrosion is observed to be quite slow in all specimens in non-isothermal aged to over-aged condition, suggesting a corrosion resistance comparable to that of RRA condition.

Microstructure Evolution and the Resulted Influence on Localized Corrosion in Al-Zn-Mg-Cu Alloy during Non-Isothermal Ageing.

Science.gov (United States)

Chen, Jun-Zhou; Li, Guo-Ai; Cai, Xin; Jiang, Jian-Tang; Shao, Wen-Zhu; Yang, Li; Zhen, Liang

2018-05-03

A non-isothermal ageing process was proposed for an Al-Zn-Mg-Cu alloy aiming to accommodate the slow heating/cooling procedure during the ageing of large components. The evolution of microstructure and microchemistry was analyzed by using transmission electron microscopy, high-angle annular dark field imaging, and energy dispersive spectrometry. The age-hardening of the alloy was examined to evaluate the strengthening behavior during the non-isothermal process. The corrosion behavior was investigated via observing the specimens immersed in EXCO solution (solution for Exfoliation Corrosion Susceptibility test in 2xxx and 7xxx series aluminum alloys, referring ASTM G34-01). Secondary precipitation was observed during the cooling stage, leading to increased precipitate number density. The distribution of grain boundary precipitates transits from discontinuous to continuous at the cooling stage, due to the secondary precipitation’s linking-up effect. The solutes’ enrichment on grain boundary precipitates and the depletion in precipitate-free zones develops during the heating procedure, but remains invariable during the cooling procedure. The corrosion in NIA (Non-isothermal Ageing) treated specimens initiates from pitting and then transits to intergranular corrosion and exfoliation corrosion. The transition from pitting to intergranular corrosion is very slow for specimens heated to 190 °C, but accelerates slightly as the cooling procedure proceeds. The transition to exfoliation corrosion is observed to be quite slow in all specimens in non-isothermal aged to over-aged condition, suggesting a corrosion resistance comparable to that of RRA condition.

Desorption isotherms of cementitious materials: study of an accelerated protocol and estimation of RVE

International Nuclear Information System (INIS)

Wu, Qier

2014-01-01

In the framework of French radioactive waste management and storage, the durability evaluation and prediction of concrete structures requires the knowledge of desorption isotherm of concrete. The aim of the present study is to develop an accelerated experimental method to obtain desorption isotherm of cementitious materials more quickly and to estimate the Representative Volume Element (RVE) size related to the desorption isotherm of concrete. In order to ensure that experimental results can be statistically considered representative, a great amount of sliced samples of cementitious materials with three different thicknesses (1 mm, 2 mm and 3 mm) have been de-saturated. The effect of slice thickness and the saturation condition on the mass variation kinetics and the desorption isotherms is analyzed. The influence of the aggregate distribution on the water content and the water saturation degree is also analyzed. A method based on statistical analysis of water content and water saturation degree is proposed to estimate the RVE for water desorption experiment of concrete. The evolution of shrinkage with relative humidity is also followed for each material during the water desorption experiment. A protocol of cycle of rapid desaturation-re-saturation is applied and shows the existence of hysteresis between desorption and adsorption. (author)

Study on isothermal precision forging process of rare earth intensifying magnesium alloy

International Nuclear Information System (INIS)

Shan, Debin; Xu, Wenchen; Han, Xiuzhu; Huang, Xiaolei

2012-01-01

A three dimensional rigid-plastic finite element model is established to simulate the isothermal precision forging process of the magnesium alloy bracket based on DEFORM 3D in order to analyze the material flow rule and determine the forging process scheme. Some problems such as underfilling and too large forging pressure are predicted and resolved through optimizing the shapes of the billet successfully. Compared to the initial microstructure, the isothermal-forged microstructure of the alloy refines obviously and amounts of secondary phases precipitate on the matrix during isothermal forging process. In subsequent ageing process, large quantities of secondary phases precipitate from α-Mg matrix with increasing ageing time. The optimal comprehensive mechanical properties of the alloy have been obtained after aged at 473 K, 63 h with the ultimate tensile strength, tensile yield strength and elongation 380 MPa, 243 MPa and 4.07% respectively, which shows good potential for application of isothermal forging process of rare earth intensifying magnesium alloy.

Kinetics Modeling and Isotherms for Adsorption of Phosphate from Aqueous Solution by Modified Clinoptilolit

Directory of Open Access Journals (Sweden)

Mohammad Malakootian

2012-01-01

Full Text Available The Phosphorous discharge into the surface water led to excessive growth of algae and eutrophication in lakes and rivers. Therefore the phosphorus removal is important due to negative effect on water resources. The aim of this study was to investigat the modification of clinoptilolite and application of modified clinoptilolite for phosphorous adsorption from aqueous solution and isotherms and kinetics modeling. Hexadecyl Trimethyl Ammonium bromide (HDTMA-Br, Hexadecyl trimethyl Ammonium Chloride (HDTMA-Cl, Sodium Decyl Sulphate (SDS and Cetrimide-C were used for modification of clinoptilolite. Experiments were conducted using jar apparatus and batch system. The effect of pH, adsorbent doses, contact time, phosphate initial concentration and particle size were studied surveyed on phosphate adsorption by modified clinoptilolite. The most common isotherms and the kinetics adsorption equations were used for determination of adsorption rate and dynamic reaction. The results showed that maximum phosphate adsorption was obtained in the pH of 7 and contact time 90min. Also it was found with the increasing of phosphate initial concentration, phosphate removal efficiency decreased significantly. Langmuir No 2 showed a good correlation compared to other isotherms (R2=0.997. Maximum adsorption capacity was obtained in 20g/L adsorbent dose (22.73mg/g. Also Interaparticle diffusion kinetics well fits with experimental data (R2=0.999 with constant rate of 3.84mg/g min0.5. The result showed that modified clinoptilolite can be used successfully as low cost and effective absorbent for phosphate removal.

Non-isothermal Moisture Transport Through Insulation Materials

DEFF Research Database (Denmark)

Peuhkuri, Ruut Hannele; Rode, Carsten; Hansen, Kurt Kielsgaard

2008-01-01

An experimental investigation was conducted in order to draw some conclusions on the magnitude of moisture transport due to temperature gradient on a range of porous light-weight building materials. A special constructed non-isothermal set-up allowed the creation of a temperature gradient of 10K...... and given humidity gradient over the sample. The resulting moisture ux as well as the hygrothermal states around and within the material were monitored. The hypothesis of relative humidity being a driving force for non-isothermal moisture transport already in the hygroscopic range could not be confirmed....... On the contrary, indications exist that the temperature gradient itself is driving the moisture from the warm side towards the cold side. An attempt to identify and quantify the single contributions of the different transport forms involved is also presented. The diferent results gave, however, diverging...

Miniaturized isothermal nucleic acid amplification, a review.

Science.gov (United States)

Asiello, Peter J; Baeumner, Antje J

2011-04-21

Micro-Total Analysis Systems (µTAS) for use in on-site rapid detection of DNA or RNA are increasingly being developed. Here, amplification of the target sequence is key to increasing sensitivity, enabling single-cell and few-copy nucleic acid detection. The several advantages to miniaturizing amplification reactions and coupling them with sample preparation and detection on the same chip are well known and include fewer manual steps, preventing contamination, and significantly reducing the volume of expensive reagents. To-date, the majority of miniaturized systems for nucleic acid analysis have used the polymerase chain reaction (PCR) for amplification and those systems are covered in previous reviews. This review provides a thorough overview of miniaturized analysis systems using alternatives to PCR, specifically isothermal amplification reactions. With no need for thermal cycling, isothermal microsystems can be designed to be simple and low-energy consuming and therefore may outperform PCR in portable, battery-operated detection systems in the future. The main isothermal methods as miniaturized systems reviewed here include nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP), helicase-dependent amplification (HDA), rolling circle amplification (RCA), and strand displacement amplification (SDA). Also, important design criteria for the miniaturized devices are discussed. Finally, the potential of miniaturization of some new isothermal methods such as the exponential amplification reaction (EXPAR), isothermal and chimeric primer-initiated amplification of nucleic acids (ICANs), signal-mediated amplification of RNA technology (SMART) and others is presented.

Nitrate sorption on activated carbon modified with CaCl2: Equilibrium, isotherms and kinetics

Directory of Open Access Journals (Sweden)

Zanella Odivan

2015-01-01

Full Text Available In this study, nitrate (NO3- removal from aqueous solutions was investigated using granular activated carbon (GAC modified with CaCl2. Batch sorption studies were performed as a function of sorbent dose, initial nitrate concentration and pH. Sorption was maximized between pH 3 and 9. Studies on the effect of pH showed that the ion exchange mechanism might be involved in the sorption process. The percentage of nitrate removed increased with increasing sorbent concentration, and the ideal sorbent dose was found to be 20 g•L-1. Four isotherm models-Langmuir, Freundlich, Redlich-Peterson and Sips-were used to fit the experimental data. The Redlich-Peterson isotherm model explained the sorption process well and showed the best coefficient of determination (0.9979 and Chi-square test statistic (0.0079. Using the Sips isotherm model, the sorption capacity (qe was found to be 1.93 mg nitrate per g of sorbent. Kinetic experiments indicated that sorption was a fast process, reaching equilibrium within 120 min. The nitrate sorption kinetic data were successfully fitted to a pseudo-second-order kinetic model. The overall results demonstrated potential applications of modified GAC for nitrate removal from aqueous solutions.

Detection of genetically modified organisms (GMOs) using isothermal amplification of target DNA sequences.

Science.gov (United States)

Lee, David; La Mura, Maurizio; Allnutt, Theo R; Powell, Wayne

2009-02-02

The most common method of GMO detection is based upon the amplification of GMO-specific DNA amplicons using the polymerase chain reaction (PCR). Here we have applied the loop-mediated isothermal amplification (LAMP) method to amplify GMO-related DNA sequences, 'internal' commonly-used motifs for controlling transgene expression and event-specific (plant-transgene) junctions. We have tested the specificity and sensitivity of the technique for use in GMO studies. Results show that detection of 0.01% GMO in equivalent background DNA was possible and dilutions of template suggest that detection from single copies of the template may be possible using LAMP. This work shows that GMO detection can be carried out using LAMP for routine screening as well as for specific events detection. Moreover, the sensitivity and ability to amplify targets, even with a high background of DNA, here demonstrated, highlights the advantages of this isothermal amplification when applied for GMO detection.

Thermal-mechanical and isothermal fatigue of IN 792 CC

International Nuclear Information System (INIS)

Beck, T.; Pitz, G.; Lang, K.-H.; Loehe, D.

1997-01-01

The cyclic deformation and lifetime behaviour of the cast Ni-base superalloy IN 792 CC was investigated both under thermal-mechanical fatigue (TMF) and isothermal fatigue (IF) conditions. During TMF the phase relations between temperature and mechanical strain were in-phase and out-of-phase, respectively. For both phase relations a similar cyclic deformation behaviour is observed. In all cases out-of-phase TMF causes tensile mean stresses, whereas in-phase TMF leads to compressive mean stresses. At T max below 800 C out-of-phase cycling results in smaller lifetimes than in-phase loading. In spite of the rather high compressive mean stresses developing at T max above 800 C, at these temperatures in-phase loading causes shorter lifetimes than out-of-phase TMF. This effect is due to the different damage mechanisms caused by in-phase and out-of-phase loadings: at higher T max considerable intergranular damage caused by in-phase loading reduces the lifetime below the respective values measured during out-of-phase TMF, after which no intergranular damage could be detected. A comparison of the TMF data with the cyclic deformation and lifetime behaviour under IF conditions shows that the material's reactions under TMF cannot be assessed satisfactorily by the results obtained from isothermal fatigue tests. (orig.)

Diagnostic Devices for Isothermal Nucleic Acid Amplification

Directory of Open Access Journals (Sweden)

Chia-Chen Chang

2012-06-01

Full Text Available Since the development of the polymerase chain reaction (PCR technique, genomic information has been retrievable from lesser amounts of DNA than previously possible. PCR-based amplifications require high-precision instruments to perform temperature cycling reactions; further, they are cumbersome for routine clinical use. However, the use of isothermal approaches can eliminate many complications associated with thermocycling. The application of diagnostic devices for isothermal DNA amplification has recently been studied extensively. In this paper, we describe the basic concepts of several isothermal amplification approaches and review recent progress in diagnostic device development.

Diagnostic devices for isothermal nucleic acid amplification.

Science.gov (United States)

Chang, Chia-Chen; Chen, Chien-Cheng; Wei, Shih-Chung; Lu, Hui-Hsin; Liang, Yang-Hung; Lin, Chii-Wann

2012-01-01

Since the development of the polymerase chain reaction (PCR) technique, genomic information has been retrievable from lesser amounts of DNA than previously possible. PCR-based amplifications require high-precision instruments to perform temperature cycling reactions; further, they are cumbersome for routine clinical use. However, the use of isothermal approaches can eliminate many complications associated with thermocycling. The application of diagnostic devices for isothermal DNA amplification has recently been studied extensively. In this paper, we describe the basic concepts of several isothermal amplification approaches and review recent progress in diagnostic device development.

Isothermal amplification detection of nucleic acids by a double-nicked beacon.

Science.gov (United States)

Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping

2016-03-01

Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use. Copyright © 2015 Elsevier Inc. All rights reserved.

Wall modeling for the simulation of highly non-isothermal unsteady flows; Modelisation de paroi pour la simulation d'ecoulements instationnaires non-isothermes

Energy Technology Data Exchange (ETDEWEB)

Devesa, A

2006-12-15

Nuclear industry flows are most of the time characterized by their high Reynolds number, density variations (at low Mach numbers) and a highly unsteady behaviour (low to moderate frequencies). High Reynolds numbers are un-affordable by direct simulation (DNS), and simulations must either be performed by solving averaged equations (RANS), or by solving only the large eddies (LES), both using a wall model. A first investigation of this thesis dealt with the derivation and test of two variable density wall models: an algebraic law (CWM) and a zonal approach dedicated to LES (TBLE-{rho}). These models were validated in quasi-isothermal cases, before being used in academic and industrial non-isothermal flows with satisfactory results. Then, a numerical experiment of pulsed passive scalars was performed by DNS, were two forcing conditions were considered: oscillations are imposed in the outer flow; oscillations come from the wall. Several frequencies and amplitudes of oscillations were taken into account in order to gain insights in unsteady effects in the boundary layer, and to create a database for validating wall models in such context. The temporal behaviour of two wall models (algebraic and zonal wall models) were studied and showed that a zonal model produced better results when used in the simulation of unsteady flows. (author)

Isotherms clustering in cosmic microwave background

International Nuclear Information System (INIS)

Bershadskii, A.

2006-01-01

Isotherms clustering in cosmic microwave background (CMB) has been studied using the 3-year WMAP data on cosmic microwave background radiation. It is shown that the isotherms clustering could be produced by the baryon-photon fluid turbulence in the last scattering surface. The Taylor-microscale Reynolds number of the turbulence is estimated directly from the CMB data as Re λ ∼10 2

Langmuir and Freundlich Isotherm Adsorption Equations for Chromium (VI) Waste Adsorption by Zeolite

International Nuclear Information System (INIS)

Murni Handayani; Eko Sulistiyono

2009-01-01

The research of chromium (VI) waste adsorption by zeolite has done. Wastes which are produced by Industries, both radioactive waste and heavy metal waste need done more processing so that they are not endanger environment and human health. Zeolite has very well-ordered crystal form with cavity each other to way entirely so that cause surface wide of zeolite become very big and very good as adsorbents. This research intends to know appropriate isotherm adsorption method to determine maximum capacity of zeolite to chromium (VI) waste. The equations which used in adsorption process are Langmuir and Freundlich isotherm Adsorption equations. The instrument was used in adsorption process by using Atomic Adsorption Spectroscopy (AAS). The experiment result showed that the biggest mass of chromium (VI) metal ion which was absorb by zeolite in 20 ppm concentration was 7.71 mg/gram zeolite. Adsorption process of Chromium (VI) waste by zeolite followed Langmuir and Freundlich isotherm equations with R 2 >0,9 . Appropriate equation to determine maximum adsorption capacity of zeolite for chromium (VI) waste adsorption is Langmuir equation. The maximum adsorption capacity of zeolite is 52.25 mg/gram. (author)

Real-time electrochemical monitoring of isothermal helicase-dependent amplification of nucleic acids.

Science.gov (United States)

Kivlehan, Francine; Mavré, François; Talini, Luc; Limoges, Benoît; Marchal, Damien

2011-09-21

We described an electrochemical method to monitor in real-time the isothermal helicase-dependent amplification of nucleic acids. The principle of detection is simple and well-adapted to the development of portable, easy-to-use and inexpensive nucleic acids detection technologies. It consists of monitoring a decrease in the electrochemical current response of a reporter DNA intercalating redox probe during the isothermal DNA amplification. The method offers the possibility to quantitatively analyze target nucleic acids in less than one hour at a single constant temperature, and to perform at the end of the isothermal amplification a DNA melt curve analysis for differentiating between specific and non-specific amplifications. To illustrate the potentialities of this approach for the development of a simple, robust and low-cost instrument with high throughput capability, the method was validated with an electrochemical system capable of monitoring up to 48 real-time isothermal HDA reactions simultaneously in a disposable microplate consisting of 48-electrochemical microwells. Results obtained with this approach are comparable to that obtained with a well-established but more sophisticated and expensive fluorescence-based method. This makes for a promising alternative detection method not only for real-time isothermal helicase-dependent amplification of nucleic acid, but also for other isothermal DNA amplification strategies.

Bithermal and isothermal experimental test design and resulting influence on the pore formation during high-temperature-induced fatigue of the alloy 800 H

International Nuclear Information System (INIS)

Hurta, S.

1991-01-01

For investigating the damaging mechanism, bithermal TMF tests have been carried out with the alloy 800H, applying fast pressure half-cycles at low temperature (e.g. 300 C) and slow tensile phases at high temperature (e.g. 700 C). The experimental data thus obtained have been compared with the results of isothermal tests performed at 700 C. Most of the experiments have been performed stress-controlled and with a constant range of plastic strain. Under this regime, deformation is induced in the case of asymmetric test design within the tensile load phase, at various constant tensile stresses each, wheras in the compressive load phase, the stress is constantly increased for compressive stress-governed testing. The results obtained from both test types show that the type of compressive load phase is the factor governing the efficiency of pore formation. (orig.) [de

Interpretation of Quasi-Isothermal Thermogravimetric Weight Curves

DEFF Research Database (Denmark)

Sørensen, Ole Toft

1979-01-01

Quasi-isothermal analysis (QIA) is a very useful technique. Compared to conventional non-isothermal thermogravimetry, close-lying reactions can easily be separated by use of this method and kinetic data can be obtained for each intermediate reaction in a single run. This paper discusses the shape...

Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster

International Nuclear Information System (INIS)

Zhang, Zun; Tang, Haibin; Kong, Mengdi; Zhang, Zhe; Ren, Junxue

2015-01-01

Published electron temperature profiles of the beam plasma from ion thrusters reveal many divergences both in magnitude and radial variation. In order to know exactly the radial distributions of electron temperature and understand the beam plasma characteristics, we applied five different experimental approaches to measure the spatial profiles of electron temperature and compared the agreement and disagreement of the electron temperature profiles obtained from these techniques. Experimental results show that the triple Langmuir probe and adiabatic poly-tropic law methods could provide more accurate space-resolved electron temperature of the beam plasma than other techniques. Radial electron temperature profiles indicate that the electrons in the beam plasma are non-isothermal, which is supported by a radial decrease (∼2 eV) of electron temperature as the plume plasma expands outward. Therefore, the adiabatic “poly-tropic law” is more appropriate than the isothermal “barometric law” to be used in electron temperature calculations. Moreover, the calculation results show that the electron temperature profiles derived from the “poly-tropic law” are in better agreement with the experimental data when the specific heat ratio (γ) lies in the range of 1.2-1.4 instead of 5/3

Adsorption Isotherms of CH 4 on Activated Carbon from Indonesian Low Grade Coal

KAUST Repository

Martin, Awaludin

2011-03-10

This article presents an experimental approach for the determination of the adsorption isotherms of methane on activated carbon that is essential for methane storage purposes. The experiments incorporated a constant-volume- variable-pressure (CVVP) apparatus, and two types of activated carbon have been investigated, namely, activated carbon derived from the low rank coal of the East of Kalimantan, Indonesia, and a Carbotech activated carbon. The isotherm results which cover temperatures from (300 to 318) K and pressures up to 3.5 MPa are analyzed using the Langmuir, Tóth, and Dubinin-Astakhov (D-A) isotherm models. The heat of adsorption for the single component methane-activated carbon system, which is concentration- and temperature-dependent, is determined from the measured isotherm data. © 2011 American Chemical Society.

Thermodynamic profiling of Peptide membrane interactions by isothermal titration calorimetry: a search for pores and micelles

DEFF Research Database (Denmark)

Henriksen, Jonas Rosager; Andresen, Thomas Lars

2011-01-01

in mixed peptide-lipid micelles. We have investigated the mode of action of the antimicrobial peptide mastoparan-X using isothermal titration calorimetry (ITC) and cryo-transmission electron microscopy (cryo-TEM). The results show that mastoparan-X induces a range of structural transitions of POPC/POPG (3...

Numerical study of inflow conditions on a turbulent isothermal or heated plane jet; Etude numerique des conditions d'emission sur un ecoulement de type jet plan turbulent isotherme ou chauffe

Energy Technology Data Exchange (ETDEWEB)

Mhiri, H.; Habli, S.; El Golli, S. [Ecole Nationale d' Ingenieurs de Monastir (Tunisia); Le Palec, G.; Bournot, Ph. [Institut de Mecanique de Marseille (France)

1999-11-01

We intend to solve equations governing turbulent plane-vertical isotherm and non isotherm jets by taking into account inflow conditions at the exit of the nozzle. The analysis is focused on the influence of these conditions on this type of flow. Two cases are considered (uniform and parabolic velocity and temperature profiles). A finite difference scheme is developed to solve the governing equations. This numeric model allows us to show that the region of fully developed regime begins much nearer the nozzle for the turbulent case than for the laminar flow case. Indeed, the turbulence increases the mixing between the incoming gas from the nozzle and the ambient fluid, and consequently the size of the potential core zone decreases. The results are compared to other works introducing mathematical variables based on the energy conservation for the case of the mixed convection and the momentum conservation for the forced convection, which allows the validation of our results. (authors)

Analysis of nitrogen and carbon tetrachloride adsorption isotherms and pore size distribution for siliceous MCM-41 synthesized from rice husk silica

Directory of Open Access Journals (Sweden)

Siriluk Chiarakorn

2004-02-01

Full Text Available RH-MCM-41 particles were synthesized using sodium silicate prepared from rice husk as a silica source and hexadecyltrimethylammonium bromide (CTAB as a surfactant. The molar compositions were 1.0SiO2: 1.1NaOH: 0.13CTAB: 0.12H2O. This material was used for adsorption isotherm studies of carbon tetrachloride (CT at 25 oC using a magnetically coupled microbalance, and compared with adsorption isotherms using nitrogen at 77 K. The CT isotherms were classified as reversible Type V isotherms, and the nitrogen adsorption isotherm was Type IVc. Capillary condensation was found in a very narrow pressure range, indicating the presence of nearly uniform pores in the RH-MCM-41 particles, which agrees very well with TEM results. The surface area estimated by using the BET method was (800 ± 8 m2 g-1. Pore size distributions (PSD of nitrogen and CT adsorption isotherms for a series of MCM-41 were calculated by using method recommended by Naono and Hakuman (1997. The pore size distributions from the nitrogen isotherm using the BJH and Naono methods showed quite narrow pore diameter distributions, centered around 27 and 29 Å, respectively. Similarly, the peak pore diameters calculated from CT isotherms using the BJH and Naono methods were 24 and 28 Å. It was found that the PSDs analyzed by the BJH method were underestimated compared to that from Naono method.

The kinetic of mass loss of grades A and B of melted TNT by isothermal and non-isothermal gravimetric methods

Directory of Open Access Journals (Sweden)

Hamid Reza Pouretedal

2018-04-01

Full Text Available The kinetic and activation energy of mass loss of two grades of melted TNT explosive, grade A and grade B, with freezing points of 80.57 and 78.15 °C, respectively, were studied by isothermal and non-isothermal gravimetric methods. In isothermal method, the mass loss of samples in containers of glass and aluminum was followed in temperatures of 80, 90 and 100 °C. The kinetic of the mass loss of the samples in the aluminum container was higher than the kinetic of it in the glass container that can be related to the effects of heat transfer and catalytic of aluminum metal. Also, the presence of impurities in grade B was due to increasing of kinetic of mass loss of it versus grade A. The non-isothermal curves were obtained in range of 30–330 °C at heating rates of 10, 15 and 20 °C⋅min−1. The TG/DTG data were used for determination of activation energy (Ea of mass loss of TNT samples upon degradation by using Ozawa, Kissinger, Ozawa-Flynn-Wall (OFW and Kissinger-Akahira-Sunose (KAS methods as model free methods. The activation energies of grades of A and B of TNT was obtained 99–120 and 66–70 kJ mol−1, respectively. The lower values of activation energy of the degradation reaction of grade B confirm the effect of impurities in the kinetics of mass loss of this grade. Keywords: TNT, Isothermal, Non-isothermal, Kinetic, Mass loss

Studies of Dye Sensitisation Kinetics and Sorption Isotherms of Direct Red 23 on Titania

Directory of Open Access Journals (Sweden)

Peter J. Holliman

2008-01-01

Full Text Available Sorption kinetics and isotherms have been measured for a commercial dye (Direct Red 23 on different samples of powdered Titania, and the data were analysed to better understand the dye sensitization process for dye sensitised solar cells (DSSCs. For the sorption kinetics, the data show rapid initial sorption (<1 hour followed by slower rate of increasing uptake between 1 and 24 hours. While higher initial concentrations of dye correspond to higher sorption overall, less dye is absorbed from higher initial dye concentrations when considered as percentage uptake. The correlation between the sorption data and model isotherms has been considered with time. The Langmuir model shows better correlations compared to the Freundlich isotherm. The dye uptake data has also been correlated with Titania characterization data (X-ray diffraction, scanning electron microscopy, BET and zero point charge analysis. Kinetic data show significantly better fits to second-order models compared to first order. This suggests that chemisorption is taking place and that the interaction between the dye sorbate and the Titania sorbent involves electron sharing to form an ester bond.

Isothermal calorimeter for reactor radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Radak, B; Markovic, V [Institute of Nuclear Sciences Boris Kidric, Odeljenje za radijacionu hemiju, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

An isothermal calorimeter with thermistors for measuring absorbed dose rates from 10{sup 4}-5-6.10{sup 5} rad/h in reactor experimental holes has been designed. A kinetics method for determining the equilibrium temperature difference has been developed, and its application in isothermal calorimetry proved. The expected accuracy in measurements within {+-} 2-5% has been proved by measurements carried out in the reactor. Some data obtained by measurements in the reactor RA are presented (author)

PENGARUH ISOTERM SORPSI AIR TERHADAP STABILITAS BERAS UBI [Effect of Moisture Sorption Isotherm to Stability of “Sweet Potato Rice”

Directory of Open Access Journals (Sweden)

Sri Widowati1*

2010-12-01

Full Text Available “Sweet Potato Rice” stability as a dry food product was determined by water activity (aw and equilibrium moisture content (Me. This relationship is known as moisture sorption isotherm. This research were aimed 1 to study moisture sorption isotherm of “Sweet Potato Rice” from sweet potato flour (Cangkuang variety and native/heat moisture treatment (HMT starch which was stored at the range of aw:0.06 - 0.96 and 28oC; 2 to determine an appropriate model for describing product moisture sorption isotherm and 3 to predict “Sweet Potato Rice” shelf of life. Experimental design used was a random complete design with two factor, namely: 1 sweet potato starch: native and HMT, and 2 packaging material: polyethylene (PE and polypropylene (PP.The result showed that the moisture sorption isotherm profiles were sigmoid. Smith equation was the best model which described moisture sorption isotherm with R2= 0,991-0,993 for adsorption and R2= 0,964-0,971 for desorption. Shelf life test showed that “Sweet Potato Rice” from Cangkuang flour and modified starch had longer shelf life (5.67 months when packed in PP bag and 2.3 months when packed in PE bag; while shelf life artificial sweet potato made from Cangkuang flour and native starch was 4.24 months when packed in PP bag and 1.72 months when packed in PE bag.

Detection of foot-and-mouth disease virus rna by reverse transcription loop-mediated isothermal amplification

Directory of Open Access Journals (Sweden)

Chen Hao-tai

2011-11-01

Full Text Available Abstract A reverse transcription loop-mediated isothermal amplification (RT-LAMP assay was developed for foot-and-mouth disease virus (FMDV RNA. The amplification was able to finish in 45 min under isothermal condition at 64°C by employing a set of four primers targeting FMDV 2B. The assay showed higher sensitivity than RT-PCR. No cross reactivity was observed from other RNA viruses including classical swine fever virus, swine vesicular disease, porcine reproductive and respiratory syndrome virus, Japanese encephalitis virus. Furthermore, the assay correctly detected 84 FMDV positive samples but not 65 FMDV negative specimens. The result indicated the potential usefulness of the technique as a simple and rapid procedure for the detection of FMDV infection.

Non-isothermal crystallization kinetics and characterization of biodegradable poly(butylene succinate-co-neopentyl glycol succinate) copolyesters.

Science.gov (United States)

Xie, Wen-Jie; Zhou, Xiao-Ming

2015-01-01

Both biodegradable aliphatic neat poly(butylene succinate) (PBS) and poly(butylene succinate-co-neopentyl glycol succinate) (P(BS-co-NPGS)) copolyesters with different 1,4-butanediol/neopentyl glycol ratios were synthesized through a two-step process of transesterification and polycondensation using stannous chloride and 4-Methylbenzenesulfonic acid as the co-catalysts. The structure, non-isothermal crystallization behavior, crystalline morphology and crystal structure of neat PBS and P(BS-co-NPGS) copolyesters were characterized by (1)H NMR, differential scanning calorimetry (DSC), polarized optical microscope (POM) and wide angle X-ray diffraction (WAXD), respectively. The Avrami equation modified by Jeziorny and Mo's method was employed to describe the non-isothermal crystallization kinetics of the neat PBS and its copolyesters. The modified Avrami equation could adequately describe the primary stage of non-isothermal crystallization kinetics of the neat PBS and its copolyesters. Mo's method provided a fairly satisfactory description of the non-isothermal crystallization of neat PBS and its copolyesters. Interestingly, the values of 1/t1/2, Zc and F(T) obtained by the modified Avrami equation and Mo's method analysis indicated that the crystallization rate increased first and then decreased with an increase of NPGS content compared that of neat PBS, whereas the crystallization mechanism almost kept unchanged. The results of tensile testing showed that the ductility of PBS was largely improved by incorporating NPGS units. The elongation at break increased remarkably with increasing NPGS content. In particular, the sample with 20% NPGS content showed around 548% elongation at break. Copyright © 2014 Elsevier B.V. All rights reserved.

Fragmentation in rotating isothermal protostellar clouds

International Nuclear Information System (INIS)

Bodenheimer, P.; Black, D.C.

1980-01-01

In this paper we report briefly the results of an extensive set of 3-D hydrodynamic calculations that have been performed during the past two and one-half years to investigate the susceptibility of rotating clouds to gravitational fragmentation. Because of the immensity of parameter space and the expense of computations, we have chosen to restrict this investigation to strictly isothermal collapse sequences. (orig./WL)

Use of phase change materials during compressed air expansion for isothermal CAES plants

Science.gov (United States)

Castellani, B.; Presciutti, A.; Morini, E.; Filipponi, M.; Nicolini, A.; Rossi, F.

2017-11-01

Compressed air energy storage (CAES) plants are designed to store compressed air into a vessel or in an underground cavern and to expand it in an expansion turbine when energy demand is high. An innovative CAES configuration recently proposed is the isothermal process. Several methods to implement isothermal CAES configuration are under investigation. In this framework, the present paper deals with the experimental testing of phase change materials (PCM) during compressed air expansion phase. The experimental investigation was carried out by means of an apparatus constituted by a compression section, a steel pressure vessel, to which an expansion valve is connected. The initial internal absolute pressure was equal to 5 bar to avoid moisture condensation and the experimental tests were carried out with two paraffin-based PCM amounts (0.05 kg and 0.1 kg). Results show that the temperature change during air expansion decreases with increasing the PCM amount inside the vessel. With the use of PCM during expansions an increase of the expansion work occurs. The increase is included in the range from 9.3% to 18.2%. In every test there is an approach to the isothermal values, which represent the maximum theoretical value of the obtainable expansion work.

Ice formation in PEM fuel cells operated isothermally at sub-freezing temperatures

Energy Technology Data Exchange (ETDEWEB)

Mukundan, Rangachary [Los Alamos National Laboratory; Luhan, Roger W [Los Alamos National Laboratory; Davey, John R [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Hussey, Daniel S [NIST; Jacobson, David L [NIST; Arif, Muhammad [NIST

2009-01-01

The effect of MEA and GDL structure and composition on the performance of single-PEM fuel cells operated isothermally at subfreezing temperatures is presented. The cell performance and durability are not only dependent on the MEA/GDL materials used but also on their interfaces. When a cell is operated isothermally at sub-freezing temperatures in constant current mode, the water formation due to the current density initially hydrates the membrane/ionomer and then forms ice in the catalyst layer/GDL. An increase in high frequency resistance was also observed in certain MEAs where there is a possibility of ice formation between the catalyst layer and GDL leading to a loss in contact area. The total water/ice holding capacity for any MEA was lower at lower temperatures and higher current densities. The durability of MEAs subjected to multiple isothermal starts was better for LANL prepared MEAs as compared to commercial MEAs, and cloth GDLs when compared to paper GDLs. The ice formation was monitored using high-resolution neutron radiography and was found to be concentrated near the cathode catalyst layer. However, there was significant ice formation in the GDLs especially at the higher temperature ({approx} -10 C) and lower current density (0.02 A/cm{sup 2}) operations. These results are consistent with the longer-term durability observations that show more severe degradation at the lower temperatures.

Isotherm, kinetic, and thermodynamic study of ciprofloxacin sorption on sediments.

Science.gov (United States)

Mutavdžić Pavlović, Dragana; Ćurković, Lidija; Grčić, Ivana; Šimić, Iva; Župan, Josip

2017-04-01

In this study, equilibrium isotherms, kinetics and thermodynamics of ciprofloxacin on seven sediments in a batch sorption process were examined. The effects of contact time, initial ciprofloxacin concentration, temperature and ionic strength on the sorption process were studied. The K d parameter from linear sorption model was determined by linear regression analysis, while the Freundlich and Dubinin-Radushkevich (D-R) sorption models were applied to describe the equilibrium isotherms by linear and nonlinear methods. The estimated K d values varied from 171 to 37,347 mL/g. The obtained values of E (free energy estimated from D-R isotherm model) were between 3.51 and 8.64 kJ/mol, which indicated a physical nature of ciprofloxacin sorption on studied sediments. According to obtained n values as measure of intensity of sorption estimate from Freundlich isotherm model (from 0.69 to 1.442), ciprofloxacin sorption on sediments can be categorized from poor to moderately difficult sorption characteristics. Kinetics data were best fitted by the pseudo-second-order model (R 2  > 0.999). Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were calculated to estimate the nature of ciprofloxacin sorption. Results suggested that sorption on sediments was a spontaneous exothermic process.

Adsorption isotherms and kinetics for dibenzothiophene on activated

Indian Academy of Sciences (India)

Adsorption isotherms were obtained and desulphurization kinetics were carried out on solutions of dibenzothiophene (DBT) and thiophene in a model fuel. The efficiencies of DBT and thiophene removal were reported. The adsorption isotherms fitted the Langmuir and Freundlich models. The highest adsorption capacity for ...

Removal Rate of Organic Matter Using Natural Cellulose via Adsorption Isotherm and Kinetic Studies.

Science.gov (United States)

Din, Mohd Fadhil Md; Ponraj, Mohanadoss; Low, Wen-Pei; Fulazzaky, Mohamad Ali; Iwao, Kenzo; Songip, Ahmad Rahman; Chelliapan, Shreeshivadasan; Ismail, Zulhilmi; Jamal, Mohamad Hidayat

2016-02-01

In this study, the removal of natural organic matter (NOM) using coconut fiber (CF) and palm oil fiber (POF) was investigated. Preliminary analysis was performed using a jar test for the selection of optimal medium before the fabricated column model experiment. The equilibrium studies on isotherms and kinetic models for NOM adsorption were analyzed using linearized correlation coefficient. Results showed that the equilibrium data were fitted to Langmuir isotherm model for both CF and POF. The most suitable adsorption model was the pseudo-first-order kinetic model for POF and pseudo-second-order kinetic model for CF. The adsorption capacities achieved by the CF and POF were 15.67 and 30.8 mg/g respectively. Based on this investigation, it can be concluded that the POF is the most suitable material for the removal of NOM in semi polluted river water.

Isothermal and non-isothermal infiltration and deuterium transport: a case study in a soil column from a headwater catchment

Czech Academy of Sciences Publication Activity Database

Sobotková, M.; Sněhota, M.; Budínová, E.; Tesař, Miroslav

2017-01-01

Roč. 65, č. 3 (2017), s. 234-243 ISSN 0042-790X Grant - others:GA ČR(CZ) GA14-03691S Institutional support: RVO:67985874 Keywords : isothermal infiltration * non-isothermal infiltration * column leaching * breakthrough curve * deuterium * viscosity * capillary trapping * entrapped air * permeability Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 1.654, year: 2016

Understand rotating isothermal collapses yet

International Nuclear Information System (INIS)

Tohline, J.E.

1985-01-01

A scalar virial equation is used to describe the dynamic properties of equilibrium gas clouds, taking into account the relative effects of surface pressure, rotation, self gravity and internal isothermal pressure. Details concerning the internal structure of the clouds are ignored in order to obtain a globalized analytical expression. The obtained solution to the equation is found to agree with the surface-pressure-dominated model of Stahler (1983), and the rotation-dominated model of Hayashi, Narita, and Miyama (1982). On the basis of the analytical expression of virial equilibrium in the clouds, some of the limiting properties of isothermal clouds are described, and a realistic starting model for cloud collapse is proposed. 18 references

Determination of the kinetic parameters of BeO using isothermal decay method

International Nuclear Information System (INIS)

Nieto, Juan Azorin; Vega, Claudia Azorin; Montalvo, Teodoro Rivera; Cabrera, Eugenio Torijano

2016-01-01

Most of the existing methods for obtaining the frequency factors make use of the trap depth (activation energy) making some assumptions about the order of the kinetics. This causes inconsistencies in the reported values of trapping parameters due that the values of the activation energy obtained by different methods differ appreciably among them. Then, it is necessary to use a method independent of the trap depth making use of the isothermal luminescence decay (ILD) method. The trapping parameters associated with the prominent glow peak of BeO (280 °C) are reported using ILD method. As a check, the trap parameters are also calculated by glow curve shape (Chen's) method after isolating the prominent glow peak by thermal cleaning technique. Our results show a very good agreement between the trapping parameters calculated by the two methods. ILD method was used for determining the trapping parameters of BeO. Results obtained applying this method are in good agreement with those obtained using other methods, except in the value of the frequency factor. - Highlights: • Kinetic parameters of BeO were determined. • Isothermal decay method was used. • Frecuency factor not agree with those obtained by other methods.

Joining of superalloy Inconel 600 by diffusion induced isothermal solidification of a liquated insert metal

International Nuclear Information System (INIS)

Egbewande, A.T.; Chukwukaeme, C.; Ojo, O.A.

2008-01-01

The effect of process variables on the microstructure of transient liquid phase bonded IN 600 using a commercial filler alloy was studied. Microstructural examination of bonded specimens showed that isothermal solidification of the liquated insert occurred during holding at the joining temperatures. In cases where the holding time was insufficient for complete isothermal solidification, the residual liquid transformed on cooling into a centerline eutectic product. The width of the eutectic decreased with increased holding time and an increase in initial gap width resulted in thicker eutectic width in specimens bonded at the same temperature and for equivalent holding times. In addition to the centerline eutectic microconstituent, precipitation of boron-rich particles was observed within the base metal region adjacent to the substrate-joint interface. Formation of these particles appeared to have influenced the rate of solidification of the liquated interlayer during bonding. In contrast to the conventional expectation of an increase in the rate of isothermal solidification with an increase in temperature, a decrease in the rate was observed with an increase in temperatures above 1160 deg. C. This could be related to a decrease in solubility of boron in nickel above the Ni-B eutectic temperature

Wall modeling for the simulation of highly non-isothermal unsteady flows

International Nuclear Information System (INIS)

Devesa, A.

2006-12-01

Nuclear industry flows are most of the time characterized by their high Reynolds number, density variations (at low Mach numbers) and a highly unsteady behaviour (low to moderate frequencies). High Reynolds numbers are un-affordable by direct simulation (DNS), and simulations must either be performed by solving averaged equations (RANS), or by solving only the large eddies (LES), both using a wall model. A first investigation of this thesis dealt with the derivation and test of two variable density wall models: an algebraic law (CWM) and a zonal approach dedicated to LES (TBLE-ρ). These models were validated in quasi-isothermal cases, before being used in academic and industrial non-isothermal flows with satisfactory results. Then, a numerical experiment of pulsed passive scalars was performed by DNS, were two forcing conditions were considered: oscillations are imposed in the outer flow; oscillations come from the wall. Several frequencies and amplitudes of oscillations were taken into account in order to gain insights in unsteady effects in the boundary layer, and to create a database for validating wall models in such context. The temporal behaviour of two wall models (algebraic and zonal wall models) were studied and showed that a zonal model produced better results when used in the simulation of unsteady flows. (author)

Nonlinear chemical sorption isotherms in the assessment of nuclear fuel waste disposal

International Nuclear Information System (INIS)

Walker, J.R.; LeNeveu, D.M.

1987-01-01

Radionuclides emplaced in an underground disposal vault can possibly migrate from the vault, and through the geosphere, to enter Man's environment. Chemical sorption is a primary mechanism for retarding this migration. The effects of nonlinear chemical sorption isotherms on radionuclide transport are discussed. A method is given by which nonlinear isotherms can be approximated by the linear sorption isotherm used in the vault submodel. The relevance of nonlinear isotherms to transport in the geosphere is discussed, and it is shown that the linear isotherm model is conservative for deep geologic disposal. 22 refs

Isothermal martensite formation at sub-zero temperatures

DEFF Research Database (Denmark)

Stojko, Allan; Hansen, Mikkel Fougt; Slycke, Jan

2012-01-01

, quenched in oil, and thereafter investigated with vibrating sample magnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the sub-zero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5 K...... with a continuation of the martensitic transformation. On prolonged isothermal holding, a volume reduction was observed for AISI 52100, but not for AISI 1070. Copyright © 2011 by ASTM International....

Water-Column Stratification Observed along an AUV-Tracked Isotherm

Science.gov (United States)

Zhang, Y.; Messié, M.; Ryan, J. P.; Kieft, B.; Stanway, M. J.; Hobson, B.; O'Reilly, T. C.; Raanan, B. Y.; Smith, J. M.; Chavez, F.

2016-02-01

Studies of marine physical, chemical and microbiological processes benefit from observing in a Lagrangian frame of reference, i.e. drifting with ambient water. Because these processes can be organized relative to specific density or temperature ranges, maintaining observing platforms within targeted environmental ranges is an important observing strategy. We have developed a novel method to enable a Tethys-class long-range autonomous underwater vehicle (AUV) (which has a propeller and a buoyancy engine) to track a target isotherm in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. In the June 2015 CANON (Controlled, Agile, and Novel Observing Network) Experiment in Monterey Bay, California, AUV Makai tracked a target isotherm for 13 hours to study the coastal upwelling system. The tracked isotherm started from 33 m depth, shoaled to 10 m, and then deepened to 29 m. The thickness of the tracked isotherm layer (within 0.3°C error from the target temperature) increased over this duration, reflecting weakened stratification around the isotherm. During Makai's isotherm tracking, another long-range AUV, Daphne, acoustically tracked Makai on a circular yo-yo trajectory, measuring water-column profiles in Makai's vicinity. A wave glider also acoustically tracked Makai, providing sea surface measurements on the track. The presented method is a new approach for studying water-column stratification, but requires careful analysis of the temporal and spatial variations mingled in the vehicles' measurements. We will present a synthesis of the water column's stratification in relation to the upwelling conditions, based on the in situ measurements by the mobile platforms, as well as remote sensing and mooring data.

Binding Isotherms and Time Courses Readily from Magnetic Resonance.

Science.gov (United States)

Xu, Jia; Van Doren, Steven R

2016-08-16

Evidence is presented that binding isotherms, simple or biphasic, can be extracted directly from noninterpreted, complex 2D NMR spectra using principal component analysis (PCA) to reveal the largest trend(s) across the series. This approach renders peak picking unnecessary for tracking population changes. In 1:1 binding, the first principal component captures the binding isotherm from NMR-detected titrations in fast, slow, and even intermediate and mixed exchange regimes, as illustrated for phospholigand associations with proteins. Although the sigmoidal shifts and line broadening of intermediate exchange distorts binding isotherms constructed conventionally, applying PCA directly to these spectra along with Pareto scaling overcomes the distortion. Applying PCA to time-domain NMR data also yields binding isotherms from titrations in fast or slow exchange. The algorithm readily extracts from magnetic resonance imaging movie time courses such as breathing and heart rate in chest imaging. Similarly, two-step binding processes detected by NMR are easily captured by principal components 1 and 2. PCA obviates the customary focus on specific peaks or regions of images. Applying it directly to a series of complex data will easily delineate binding isotherms, equilibrium shifts, and time courses of reactions or fluctuations.

Numerical studies of pulsating buoyant plume in isothermal and non isothermal situations

International Nuclear Information System (INIS)

Sharma, Pavan K.; Singh, R.K.; Mohanty, Ananya; Das, D.

2014-01-01

A computational study has been carried out for predicting the behaviour of buoyant plume in isothermal and non isothermal configuration. General simulation objectives of any buoyant flow simulation are macroscopic in nature and deals with the grass data in respect of buoyancy induced scalar transport. However, the accuracy of predicting such macroscopic parameters is a strong function of several other microscopic parameters which govern the overall macroscopic behaviour. Some of the microscopic parameters for analysis could be buoyancy induced stable/unstable flows, relative plume behaviour, baroclinic velocity distribution etc. Only the CFD based flow modelling approach is capable of calculating several of these aspects. LES based modelling scores over the conventional RANS based computational modelling. The primary objective of the present study was to model buoyant plume simulation of different types in order to explore the details regarding plume and flow structure, instabilities and puffing behaviour. One of the influencing parameters on the overall plume behaviour is the buoyancy resolution index i.e. fineness of chosen grid in relation to the buoyancy intensity and other hydrodynamic parameters. The grid sensitivity studies have been carried out to find out the optimum value grid size by way of buoyant pool fire simulations. Comparative simulation has also been made for a square and round pool fire and it was found that for engineering simulations equivalent area square pool modeling is sufficient. Using the optimum value of grid size and square pool shape simulations have been carried out for different value of fire intensity. The flame puffing frequency as calculated by the reported correlation was compared against the computationally observed puffing frequency and the agreement was generally found to be excellent. Besides these results the comparisons of predicted peak flames temperatures data for various case studies with the available experimental data

Isotherm, kinetic and thermodynamics study of humic acid removal process from aquatic environment by chitosan nano particle

Directory of Open Access Journals (Sweden)

Maryam Ghafoori

2016-09-01

Full Text Available Background and Aim: Humic substances include natural organic polyelectrolyte materials that formed most of the dissolved organic carbon in aquatic environments. Reaction between humic substances and chlorine leading to formation of disinfection byproducts (DBPs those are toxic, carcinogenic and mutagenic. The aim of this study was investigation of isotherms, kinetics and thermodynamics of humic acid removal process by nano chitosan from aquatic environment. Materials and Methods: This practical research was an experimental study that performed in a batch system. The effect of various parameters such as pH, humic acid concentration, contact time, adsorbent dosage, isotherms, thermodynamics and Kinetics of humic acid adsorption process were investigated. Humic acid concentration measured using spectrophotometer at wave length of 254 nm. Results: The results of this research showed that maximum adsorption capacity of nanochitosan that fall out in concentration of 50 mg/l and contact time of 90 minutes was 52.34 mg/g. Also, the maximum adsorption was observed in pH = 4 and adsorbent dosage 0.02 g. Laboratory data show that adsorption of humic acid by nanochitosan follow the Langmuir isotherm model. According to result of thermodynamic study, entropy changes (ΔS was equal to 2.24 J/mol°k, enthalpy changes (ΔH was equal to 870 kJ/mol and Gibbs free energy (ΔG was negative that represent the adsorption process is spontaneous and endothermic. The kinetics of adsorption has a good compliant with pseudo second order model. Conclusion: Regarding to results of this study, nano chitosan can be suggested as a good adsorbent for the removal of humic acids from aqueous solutions.

ISOTHERMAL AIR INGRESS VALIDATION EXPERIMENTS AT IDAHO NATIONAL LABORATORY: DESCRIPTION AND SUMMARY OF DATA

International Nuclear Information System (INIS)

Oh, Chang H.; Kim, Eung S.

2010-01-01

Idaho National Laboratory performed air ingress experiments as part of validating computational fluid dynamics code (CFD). An isothermal stratified flow experiment was designed and set to understand stratified flow phenomena in the very high temperature gas cooled reactor (VHTR) and to provide experimental data for validating computer codes. The isothermal experiment focused on three flow characteristics unique in the VHTR air-ingress accident: stratified flow in the horizontal pipe, stratified flow expansion at the pipe and vessel junction, and stratified flow around supporting structures. Brine and sucrose were used as heavy fluids and water was used as light fluids. The density ratios were changed between 0.87 and 0.98. This experiment clearly showed that a stratified flow between heavy and light fluids is generated even for very small density differences. The code was validated by conducting blind CFD simulations and comparing the results to the experimental data. A grid sensitivity study was also performed based on the Richardson extrapolation and the grid convergence index method for modeling confidence. As a result, the calculated current speed showed very good agreement with the experimental data, indicating that the current CFD methods are suitable for predicting density gradient stratified flow phenomena in the air-ingress accident.

High Pressure Adsorption Isotherm of CO2 on Activated Carbon using Volumetric Method

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Awaludin Martin

2011-05-01

Full Text Available Adsorption system is ones of the most effective methods for CO2 separating with other substances that produced from the burning of fossil fuels. In the design for that application, beside of characteristics of porous material (adsorbent data, CO2 adsorption data on the adsorbent (kinetic and thermodynamic are also needed. The aim of this research is resulting isothermal adsorption data at pressures up to 3.5 MPa by indirect methods (volumetric method at isothermal temperature of 300, 308, 318 and 338 K. Adsorbent that used in this research is activated carbon made from East of Kalimantan coals by physical activation method (CO2 which is the surface area of activated carbon is 668 m2/g and pore volume is 0.47 mL/g. Carbon dioxide (CO2 that used in this research is high purity carbon dioxide with a purity of 99.9%. Data from the experiment results then correlated using the Langmuir and Toth equations model. The results showed that the maximum adsorption capacity is 0.314 kg/kg at 300 K and 3384.69 kPa. The results of regression of experiment data using Langmuir and Toth models were 3.4% and 1.7%.

Precipitation and impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel during isothermal aging

International Nuclear Information System (INIS)

Han, Jian; Li, Huijun; Barbaro, Frank; Jiang, Laizhu; Zhu, Zhixiong; Xu, Haigang; Ma, Li

2014-01-01

The effect of isothermal aging on precipitation behaviour and Charpy impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel was investigated by means of Thermo-Calc prediction, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Charpy impact toughness testing. The results show that, niobium, vanadium carbides and nitrides, Fe 2 Nb (Laves phase) and Cr 23 C 6 formed after 2 h aging at 800 °C, and the equilibrium solvus temperature of Fe 2 Nb phase increases to above 750 °C, higher than the calculated temperature (730 °C) using Thermo-Calc. After isothermal aging at 750–950 °C, 2 h aging resulted in a decrease in toughness due to the formation of precipitation, especially (Nb,V)(C,N) and Fe 2 Nb. When isothermally aged at 800 °C for up to 24 h, the coarsening rate of Fe 2 Nb particle is much higher than that of (Nb,V)(C,N), and the impact toughness of the steel is dependent on quantity and sizes of (Nb,V)(C,N) and Fe 2 Nb particles

Precipitation and impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel during isothermal aging

Energy Technology Data Exchange (ETDEWEB)

Han, Jian, E-mail: jh595@uowmail.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Li, Huijun [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Barbaro, Frank [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); CBMM Technology Suisse, 14, Rue du Rhone, Geneve 1204 (Switzerland); Jiang, Laizhu [Baoshan Iron and Steel Co., Ltd., Shanghai 200431 (China); Zhu, Zhixiong [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Xu, Haigang; Ma, Li [Baoshan Iron and Steel Co., Ltd., Shanghai 200431 (China)

2014-08-26

The effect of isothermal aging on precipitation behaviour and Charpy impact toughness of Nb–V stabilised 18Cr–2Mo ferritic stainless steel was investigated by means of Thermo-Calc prediction, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Charpy impact toughness testing. The results show that, niobium, vanadium carbides and nitrides, Fe{sub 2}Nb (Laves phase) and Cr{sub 23}C{sub 6} formed after 2 h aging at 800 °C, and the equilibrium solvus temperature of Fe{sub 2}Nb phase increases to above 750 °C, higher than the calculated temperature (730 °C) using Thermo-Calc. After isothermal aging at 750–950 °C, 2 h aging resulted in a decrease in toughness due to the formation of precipitation, especially (Nb,V)(C,N) and Fe{sub 2}Nb. When isothermally aged at 800 °C for up to 24 h, the coarsening rate of Fe{sub 2}Nb particle is much higher than that of (Nb,V)(C,N), and the impact toughness of the steel is dependent on quantity and sizes of (Nb,V)(C,N) and Fe{sub 2}Nb particles.

An Isothermal Steam Expander for an Industrial Steam Supplying System

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Chen-Kuang Lin

2015-01-01

Full Text Available Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator is replaced by a steam expander. With this steam expander, the pressure will be transformed into mechanical energy and extracted during the expansion process. A new type of isothermal steam expander for an industrial steam supplying system will be presented in the paper. The isothermal steam expander will improve the energy efficiency of a traditional steam expander by replacing the isentropic process with an isothermal expansion process. With this, steam condensation will decrease, energy will increase, and steam quality will be improved. Moreover, the mathematical model of the isothermal steam expander will be established by using the Schmidt theory, the same principle used to analyze Stirling engines. Consequently, by verifying the correctness of the theoretical model for the isothermal steam expander using experimental data, a prototype of 100 c.c. isothermal steam expander is constructed.

Rapid Newcastle Disease Virus Detection Based on Loop-Mediated Isothermal Amplification and Optomagnetic Readout

DEFF Research Database (Denmark)

Tian, Bo; Ma, Jing; Zardán Gómez de la Torre, Teresa

2016-01-01

Rapid and sensitive diagnostic methods based on isothermal amplification are ideal substitutes for PCR in out-of-lab settings. However, there are bottlenecks in terms of establishing low-cost and user-friendly readout methods for isothermal amplification schemes. Combining the high amplification...... efficiency of loop-mediated isothermal amplification (LAMP) with an optomagnetic nanoparticle-based readout system, we demonstrate ultrasensitive and rapid detection of Newcastle disease virus RNA. Biotinylated amplicons of LAMP and reverse transcription LAMP (RT-LAMP) bind to streptavidin-coated magnetic...... nanoparticles (MNPs) resulting in a dramatical increase in the hydrodynamic size of the MNPs. This increase was measured by an optomagnetic readout system and provided quantitative information on the amount of LAMP target sequence. Our assay resulted in a limit of detection of 10 aM of target sequence...

The software package for solving problems of mathematical modeling of isothermal curing process

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S. G. Tikhomirov

2016-01-01

Full Text Available Summary. On the basis of the general laws of sulfur vulcanization diene rubbers the principles of the effective cross-linking using a multi-component agents was discussed. It is noted that the description of the mechanism of action of the complex cross-linking systems are complicated by the diversity of interactions of components and the influence of each of them on the curing kinetics, leading to a variety technological complications of real technology and affects on the quality and technical and economic indicators of the production of rubber goods. Based on the known theoretical approaches the system analysis of isothermal curing process was performed. It included the integration of different techniques and methods into a single set of. During the analysis of the kinetics of vulcanization it was found that the formation of the spatial grid parameters vulcanizates depend on many factors, to assess which requires special mathematical and algorithmic support. As a result of the stratification of the object were identified the following major subsystems. A software package for solving direct and inverse kinetic problems isothermal curing process was developed. Information support “Isothermal vulcanization” is a set of applications of mathematical modeling of isothermal curing. It is intended for direct and inverse kinetic problems. When solving the problem of clarifying the general scheme of chemical transformations used universal mechanism including secondary chemical reactions. Functional minimization algorithm with constraints on the unknown parameters was used for solving the inverse kinetic problem. Shows a flowchart of the program. An example of solving the inverse kinetic problem with the program was introduced. Dataware was implemented in the programming language C ++. Universal dependence to determine the initial concentration of the curing agent was applied . It allowing the use of a model with different properties of multicomponent

Crystallization kinetics of the Cu50Zr50 metallic glass under isothermal conditions

International Nuclear Information System (INIS)

Gao, Qian; Jian, Zengyun; Xu, Junfeng; Zhu, Man; Chang, Fange; Han, Amin

2016-01-01

Amorphous structure of the melt-spun Cu 50 Zr 50 amorphous alloy ribbons were confirmed by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM). Isothermal crystallization kinetics of these alloy ribbons were investigated using differential scanning calorimetry (DSC). Besides, Arrhenius and Johnson-Mehl-Avrami (JMA) equations were utilized to obtain the isothermal crystallization kinetic parameters. As shown in the results, the local activation energy E α decreases by a large margin at the crystallized volume fraction α<0.1, which proves that crystallization process is increasingly easy. In addition, the local activation energy E α is basically constant at 0.1<α<0.9. Therefore, it turns out that the unchanged barrier is overcome in the crystallization process. Finally, E α rapidly decreases at 0.9<α<1, implying that crystallization becomes easier and easier to proceed. Nucleation activation energy E nucleation is greater than growth activation energy E growth , so nucleation is harder than growth in isothermal process. In terms of the local Avrami exponent n(α), it ranges 1.1–7.4, revealing that isothermal crystallization mechanism is interface-controlled one- two- or three-dimensional growth with different nucleation rates. - Graphical abstract: The local Avrami exponent n(α), it ranges 1.1–7.4, revealing that isothermal crystallization mechanism is interface-controlled one- two- or three-dimensional growth with different nucleation rates. - Highlights: • Isothermal crystallization kinetics of Cu 50 Zr 50 metallic glass was investigated. • The relationship between the local activation energy E α and the crystallized volume fraction α were determined. • The nucleation activation energy E nucleation and grain growth activation energy E growth were obtained. • The local Avrami exponent n(α) was calculated in isothermal model.

New Theoretical Expressions for the Five Adsorption Type Isotherms ...

African Journals Online (AJOL)

New Theoretical Expressions for the Five Adsorption Type Isotherms Classified by Bet Basing on Statistical Physics Treatment. ... that we have proposed, basing on statistical physics treatment, are rather powerful to better understand and interpret the various five physical adsorption Type isotherms at a microscopic level.

Wafer level hermetic packaging based on Cu-Sn isothermal solidification technology

International Nuclear Information System (INIS)

Cao Yuhan; Luo Le

2009-01-01

A novel wafer level bonding method based on Cu-Sn isothermal solidification technology is established. A multi-layer sealing ring and the bonding processing are designed, and the amount of solder and the bonding parameters are optimized based on both theoretical and experimental results. Verification shows that oxidation of the solder layer, voids and the scalloped-edge appearance of the Cu 6 Sn 5 phase are successfully avoided. An average shear strength of 19.5 MPa and an excellent leak rate of around 1.9 x 10 -9 atm cc/s are possible, meeting the demands of MIL-STD-883E. (semiconductor technology)

Non-isothermal cure and exfoliation of tri-functional epoxy-clay nanocomposites

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F. Shiravand

2015-08-01

Full Text Available The non-isothermal cure kinetics of polymer silicate layered nanocomposites based on a tri-functional epoxy resin has been investigated by differential scanning calorimetry. From an analysis of the kinetics as a function of the clay content, it can be concluded that the non-isothermal cure reaction can be considered to consist of four different processes: the reaction of epoxy groups with the diamine curing agent; an intra-gallery homopolymerisation reaction which occurs concurrently with the epoxy-amine reaction; and two extra-gallery homopolymerisation reactions, catalysed by the onium ion of the organically modified clay and by the tertiary amines resulting from the epoxy-amine reaction. The final nanostructure displays a similar quality of exfoliation as that observed for the isothermal cure of the same nanocomposite system. This implies that the intra-gallery reaction, which is responsible for the exfoliation, is not significantly inhibited by the extra-gallery epoxy-amine cross-linking reaction.

Investigation of Acorn fruit Ash Efficiency in Cadmium Removal from Aqueous Solutions: Adsorption Isotherm and Kinetic Studies

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Salman Zarei

2014-12-01

Full Text Available Background: Heavy metals are known as significant pollutants because of toxicity and nonbiodegradable characteristics. Cadmium is one of the heavy metals that have carcinogen potential. So, this study carried out in order to investigate the acorn fruit ash efficiency in cadmium removal from aqueous solutions. Methods: This study was done in the batch laboratory conditions. In this study, the effect of different parameters including pH, contact time, adsorbent dose, and initial cadmium concentration were evaluated. The Langmuir, Freundlich and Temkin isotherm models were used for analysis of the equilibrium isotherm. Adsorption kinetics of cadmium by different models were also investigated. The measurement of residual cadmium in the samples was determined by atomic absorption spectrophotometry at 228.8 nm. The SPSS-16 software was used for analysis of data. Results: According to the results, the maximum adsorption capacity of cadmium was 9.29 mg/g at pH=7 and 8 g/L adsorbent dose. The removal efficiency was increased with increasing contact time and decreased with increasing of cadmium initial concentration. Investigation of achieving data showed that the adsorption process followed better by Freundlich isotherm and the pseudo-second order kinetic. Conclusions: According to the results of this study, it could be concluded that the acorn fruit ash had high ability in cadmium adsorption and could be used as a cheap adsorbent in the removal of cadmium.

Isothermal annealing of silicon implanted with 50 keV 10B ions

International Nuclear Information System (INIS)

Weidner, B.; Zaschke, G.

1974-01-01

Isothermal annealing characteristics of silicon implanted with boron were measured and compared with calculated results. Implantation was performed with 50 keV 10 B ions in the dose range of 7.5 x 10 12 cm -2 to 2.0 x 10 15 cm -2 . Annealing temperatures ranged from 700 to 900 0 C. Maximum annealing time was 10 4 minutes. Annealing time strongly increases with increasing dose and decreasing temperature. Assuming that there is only one activation energy the isothermal annealing curves of constant dose and different temperatures were combined to a reduced annealing curve and the reduced isothermal annealing curve calculated. Starting from first order kinetics, considering the doping profile of boron in silicon and assuming a depth-dependent decay constant the experimentally determined annealing curves could be easily described over the total dose and time range

ISOTHERMAL AND THERMOMECHANICAL FATIGUE OF A NICKEL-BASE SUPERALLOY

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Carlos Carvalho Engler-Pinto Júnior

2014-06-01

Full Text Available Thermal gradients arising during transient regimes of start-up and shutdown operations produce a complex thermal and mechanical fatigue loading which limits the life of turbine blades and other engine components operating at high temperatures. More accurate and reliable assessment under non-isothermal fatigue becomes therefore mandatory. This paper investigates the nickel base superalloy CM 247LC-DS under isothermal low cycle fatigue (LCF and thermomechanical fatigue (TMF. Test temperatures range from 600°C to 1,000°C. The behavior of the alloy is strongly affected by the temperature variation, especially in the 800°C-1,000°C range. The Ramberg-Osgood equation fits very well the observed isothermal behavior for the whole temperature range. The simplified non-isothermal stress-strain model based on linear plasticity proposed to represent the thermo-mechanical fatigue behavior was able to reproduce the observed behavior for both in-phase and out-of-phase TMF cycling.

Experimental study of natural convection heat transfer from an isothermal combined geometry (downward cone- cylinder)

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, A. [Yazd Univ., Yazd (Iran, Islamic Republic of). Dept. of Mechanical Engineering; Goharkhah, M.; Ashjaee, M. [Tehran Univ., Tehran (Iran, Islamic Republic of). Dept. of Mechanical Engineering

2009-07-01

Laminar free convection heat transfer from an isothermal combined geometry which consists of a downward cone attached to a vertical cylinder was studied. In particular, a Mach-Zehnder interferometer was used to determine the change in local and average heat transfer coefficients on the surface of an isothermal combined geometry for different vertex angles. The effect of the vertex angle on heat transfer was also investigated by keeping the height of the cylinder and slant length of the cone constant for all objects. The experimental data showed that the local heat transfer coefficient on the conical part increased in the vicinity of the cylinder and cone intersection. The distance between the point of minimum heat transfer coefficient on the cone and vertex of the cone decreased as the vertex angle increased. The maximum average Nusselt number for a constant Rayleigh number was obtained for the geometry with the smallest vertex angle. For all objects, the average Nusselt number increased with an increase in the Rayleigh number. An experiment was carried out on a vertical isothermal cylinder of circular cross section in order to validate the experimental approach. An analytical solution was found to be in good agreement with experimental results. 31 refs., 9 figs.

Effects of isothermal heat treatment on nanostructured bainite morphology and microstructures in laser cladded coatings

International Nuclear Information System (INIS)

Guo, Yanbing; Feng, Kai; Lu, Fenggui; Zhang, Ke; Li, Zhuguo; Hosseini, Seyed Reza Elmi; Wang, Min

2015-01-01

Highlights: • Nanobainitic coatings under 200, 250 and 300 °C heat treatments are fabricated. • The size of bainite sheaves increased with the isothermal temperature increasing. • Textured and chaotic distributions are observed in 200 and 300 °C microstructures. • The evolution model of nanobainite morphology is established and analyzed. • The bainitic ferrite of 200 °C heat treatment has a true thickness of 45 nm. - Abstract: Laser cladding and subsequent isothermal heat treatments have been used to fabricate nanostructured bainitic coatings. XRD has been used to determine the kinetics of bainitic transformation process. OM, SEM and TEM have been used to characterize the morphology and microstructures at different stages of transformation. The results showed that at the initial stage of bainitic transformation, the bainite sheaves are short and thin at a relatively low transformation temperature. The fully transformed bainitic microstructure obtained at a relatively high temperature present a textured morphology. The chaotic growth orientations of the sheaves and the island like of the retained austenite have been observed at the low transformation temperature. A simple model has been established to describe the microstructures and the bainite sheaves growth evolutions during the isothermal holding at the different transformed temperatures. The morphology and distribution of the bainite in the coatings were analyzed by using the nucleation and growth rate of bainitic transformation theories, which is consisted with the experiment results.

Effects of isothermal heat treatment on nanostructured bainite morphology and microstructures in laser cladded coatings

Energy Technology Data Exchange (ETDEWEB)

Guo, Yanbing [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Feng, Kai; Lu, Fenggui; Zhang, Ke [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composite, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Hosseini, Seyed Reza Elmi [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Min [Shanghai Key Lab of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composite, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2015-12-01

Highlights: • Nanobainitic coatings under 200, 250 and 300 °C heat treatments are fabricated. • The size of bainite sheaves increased with the isothermal temperature increasing. • Textured and chaotic distributions are observed in 200 and 300 °C microstructures. • The evolution model of nanobainite morphology is established and analyzed. • The bainitic ferrite of 200 °C heat treatment has a true thickness of 45 nm. - Abstract: Laser cladding and subsequent isothermal heat treatments have been used to fabricate nanostructured bainitic coatings. XRD has been used to determine the kinetics of bainitic transformation process. OM, SEM and TEM have been used to characterize the morphology and microstructures at different stages of transformation. The results showed that at the initial stage of bainitic transformation, the bainite sheaves are short and thin at a relatively low transformation temperature. The fully transformed bainitic microstructure obtained at a relatively high temperature present a textured morphology. The chaotic growth orientations of the sheaves and the island like of the retained austenite have been observed at the low transformation temperature. A simple model has been established to describe the microstructures and the bainite sheaves growth evolutions during the isothermal holding at the different transformed temperatures. The morphology and distribution of the bainite in the coatings were analyzed by using the nucleation and growth rate of bainitic transformation theories, which is consisted with the experiment results.

Absorption of calcium ions on oxidized graphene sheets and study its dynamic behavior by kinetic and isothermal models

Directory of Open Access Journals (Sweden)

Mahmoud Fathy

2016-07-01

Full Text Available Abstract Sorption of calcium ion from the hard underground water using novel oxidized graphene (GO sheets was studied in this paper. Physicochemical properties and microstructure of graphene sheets were investigated using Raman spectrometer, thermogravimetry analyzer, transmission electron microscope, scanning electron microscope. The kinetics adsorption of calcium on graphene oxide sheets was examined using Lagergren first and second orders. The results show that the Lagergren second-order was the best-fit model that suggests the conception process of calcium ion adsorption on the Go sheets. For isothermal studies, the Langmuir and Freundlich isotherm models were used at temperatures ranging between 283 and 313 K. Thermodynamic parameters resolved at 283, 298 and 313 K indicating that the GO adsorption was exothermic spontaneous process. Finally, the graphene sheets show high partiality toward calcium particles and it will be useful in softening and treatment of hard water.

Measurement and analysis of adsorption isotherms of CO_2 on activated carbon

International Nuclear Information System (INIS)

Singh, Vinod Kumar; Anil Kumar, E.

2016-01-01

In the present work CO_2 adsorption isotherms of a commercially available activated carbon, Norit Darco type obtained from lignite granular material, were measured. Adsorption isotherms were measured at different temperatures 298 K, 308 K, 318 K and 338 K and over a pressure range of 0–45 bar using Sievert's type experimental setup. Experimental data of CO_2 adsorption isotherms were modelled using Langmuir and Dubinin–Astakhov (D–A) isotherm models. Based on coefficient of correlation and normalized standard deviation it was found that D–A isotherm model was well suited with the experimental data of CO_2 adsorption isotherms. The important thermodynamic properties viz., limiting heat of adsorption at zero coverage, entropy, Gibbs free energy and isosteric heat of adsorption as a function of surface coverage were evaluated using van't Hoff and Clausius–Clapeyron equations. These thermodynamic properties were indicating that CO_2 uptake by activated carbon is a physisorption phenomenon. The adsorption isotherms data and the thermodynamic parameters estimated in the present study are useful for designing of an adsorption based gas storage systems.

Magnetic vinylphenyl boronic acid microparticles for Cr(VI) adsorption: Kinetic, isotherm and thermodynamic studies

International Nuclear Information System (INIS)

Kara, Ali; Demirbel, Emel; Tekin, Nalan; Osman, Bilgen; Beşirli, Necati

2015-01-01

Highlights: • Cr(VI) can oxidize biological molecules and be one of the most harmful substance. • Magnetic seperation techniques are used on different applications in many fields. • Magnetic systems can be used for rapid and selective removal as a magnetic processor. • We investigate properties of both new material and other magnetic adsorbents reported in the literatures on the adsorption of Cr(VI) ions. • No researchments were reported on adsorption of Cr(VI) with magnetic vinylphenyl boronic acid microparticles. - Abstract: Magnetic vinylphenyl boronic acid microparticles, poly(ethylene glycol dimethacrylate(EG)–vinylphenyl boronic acid(VPBA)) [m-poly(EG–VPBA)], produced by suspension polymerization and characterized, was found to be an efficient solid polymer for Cr(VI) adsorption. The m-poly(EG–VPBA) microparticles were prepared by copolymerizing of ethylene glycol dimethylacrylate (EG) with 4-vinyl phenyl boronic acid (VPBA). The m-poly(EG–VPBA) microparticles were characterized by N 2 adsorption/desorption isotherms, electron spin resonance (ESR), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), elemental analysis, scanning electron microscope (SEM) and swelling studies. The m-poly(EG–VPBA) microparticles were used at adsorbent/Cr(VI) ion ratios. The influence of pH, Cr(VI) initial concentration, temperature of the removal process was investigated. The maximum removal of Cr(VI) was observed at pH 2. Langmuir isotherm and Dubinin–Radushkvich isotherm were found to better fit the experiment data rather than Fruendlich isotherm. The kinetics of the adsorption process of Cr(VI) on the m-poly(EG–VPBA) microparticles were investigated using the pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models, results showed that the pseudo-second order equation model provided the best correlation with the experimental results. The thermodynamic

Experiences of fitting isotherms to data from batch sorption experiments for radionuclides on tuffs

International Nuclear Information System (INIS)

Polzer, W.L.; Fuentes, H.R.

1989-11-01

Laboratory experiments have been performed on the sorption of radionuclides on tuff as site characterization information for the Yucca Mountain Project. This paper presents general observations on the results of curve-fitting of sorption data by isotherm equations and the effects of experimental variables on their regressional analysis. Observations are specific to the effectiveness and problems associated with fitting isotherms, the calculation and value of isotherm parameters, and the significance of experimental variables such as replication, particle size, mode of sorption, and mineralogy. These observations are important in the design of laboratory experiments to ensure that collected data are adequate for effectively characterizing sorption of radionuclides on tuffs or other materials. 13 refs., 2 figs., 4 tabs

Isothermal approach to predict the removal efficiency of β-carotene adsorption from CPO using activated carbon produced from tea waste

Science.gov (United States)

Harahap, S. A. A.; Nazar, A.; Yunita, M.; Pasaribu, RA; Panjaitan, F.; Yanuar, F.; Misran, E.

2018-02-01

Adsorption of β-carotene in crude palm oil (CPO) was studied using activated carbon produced from tea waste (ACTW) an adsorbent. Isothermal studies were carried out at 60 °C with the ratio of activated carbon to CPO were 1:3, 1:4, 1:5, and 1:6, respectively. The ACTW showed excellent performance as the percentage of adsorption of β-carotene from CPO was > 99%. The best percentage removal (R) was achieved at ACTW to CPO ratio equal to 1:3, which was 99.61%. The appropriate isotherm model for this study was Freundlich isotherm model. The combination of Freundlich isotherm equation and mass balance equation showed a good agreement when validated to the experimental data. The equation subsequently executed to predict the removal efficiency under given sets of operating conditions. At a targetted R, CPO volume can be estimated for a certain initial concentration β-carotene in CPO C0 and mass of ACTW adsorbent M used.

Mathematical Modeling of Moisture Sorption Isotherms and Determination of Isosteric Heats of Sorption of Ziziphus Leaves

Directory of Open Access Journals (Sweden)

Amel Saad

2014-01-01

Full Text Available Desorption and adsorption equilibrium moisture isotherms of Ziziphus spina-christi leaves were determined using the gravimetric-static method at 30, 40, and 50°C for water activity (aw ranging from 0.057 to 0.898. At a given aw, the results show that the moisture content decreases with increasing temperature. A hysteresis effect was observed. The experimental data of sorption were fitted by eight models (GAB, BET, Henderson-Thompson, modified-Chung Pfost, Halsey, Oswin, Peleg, and Adam and Shove. After evaluating the models according to several criteria, the Peleg and Oswin models were found to be the most suitable for describing the sorption curves. The net isosteric heats of desorption and adsorption of Ziziphus spina-christi leaves were calculated by applying the Clausius-Clapeyron equation to the sorption isotherms and an expression for predicting these thermodynamic properties was given.

Isotopically exchangeable phosphorus as a correction value to adsorption isotherms

International Nuclear Information System (INIS)

Lopez, S.C.; Barbaro, N.O.; Rojas de Tramontini, S.L.; Martini, O.

1984-01-01

Adsorption isotherms in evaluation and characterization of soils are studied. The quantity of phosphorus present at first in soil, evaluated by radioisotopic techniques and used in correction of Langmuir and Freundlich isotherms, is discussed. (M.A.C.) [pt

Detection of the 35S promoter in transgenic maize via various isothermal amplification techniques: a practical approach.

Science.gov (United States)

Zahradnik, Celine; Kolm, Claudia; Martzy, Roland; Mach, Robert L; Krska, Rudolf; Farnleitner, Andreas H; Brunner, Kurt

2014-11-01

In 2003 the European Commission introduced a 0.9% threshold for food and feed products containing genetically modified organism (GMO)-derived components. For commodities containing GMO contents higher than this threshold, labelling is mandatory. To provide a DNA-based rapid and simple detection method suitable for high-throughput screening of GMOs, several isothermal amplification approaches for the 35S promoter were tested: strand displacement amplification, nicking-enzyme amplification reaction, rolling circle amplification, loop-mediated isothermal amplification (LAMP) and helicase-dependent amplification (HDA). The assays developed were tested for specificity in order to distinguish between samples containing genetically modified (GM) maize and non-GM maize. For those assays capable of this discrimination, tests were performed to determine the lower limit of detection. A false-negative rate was determined to rule out whether GMO-positive samples were incorrectly classified as GMO-negative. A robustness test was performed to show reliable detection independent from the instrument used for amplification. The analysis of three GM maize lines showed that only LAMP and HDA were able to differentiate between the GMOs MON810, NK603, and Bt11 and non-GM maize. Furthermore, with the HDA assay it was possible to realize a detection limit as low as 0.5%. A false-negative rate of only 5% for 1% GM maize for all three maize lines shows that HDA has the potential to be used as an alternative strategy for the detection of transgenic maize. All results obtained with the LAMP and HDA assays were compared with the results obtained with a previously reported real-time PCR assay for the 35S promoter in transgenic maize. This study presents two new screening assays for detection of the 35S promoter in transgenic maize by applying the isothermal amplification approaches HDA and LAMP.

Modeling of adsorption isotherms of phenol and chlorophenols onto granular activated carbon. Part I. Two-parameter models and equations allowing determination of thermodynamic parameters.

Science.gov (United States)

Hamdaoui, Oualid; Naffrechoux, Emmanuel

2007-08-17

The adsorption equilibrium isotherms of five phenolic compounds from aqueous solutions onto granular activated carbon (GAC) were studied and modeled. Phenol (Ph), 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP), and 2,4,6-trichlorophenol (TCP) were chosen for the adsorption tests. To predict the adsorption isotherms and to determine the characteristic parameters for process design, seven isotherm models: Langmuir (five linear forms), Freundlich, Elovich, Temkin, Fowler-Guggenheim, Kiselev, and Hill-de Boer models were applied to experimental data. The results reveal that the adsorption isotherm models fitted the data in the order: Fowler-Guggenheim>Hill-de Boer>Temkin>Freundlich>Kiselev>Langmuir isotherms. Adsorption isotherms modeling shows that the interaction of phenolic compounds with activated carbon surface is localized monolayer adsorption, that is adsorbed molecules are adsorbed at definite, localized sites. Each site can accommodate only one molecule. The interaction among adsorbed molecules is repulsive and there is no association between them, adsorption is carried out on energetically different sites and is an exothermic process. Uptake of phenols increases in the order Ph<2-CP<4-CP

Helicase Dependent Isothermal Amplification of DNA and RNA using Self-Avoiding Molecular Recognition Systems

Science.gov (United States)

Yang, Zunyi; McLendon, Chris; Hutter, Daniel; Bradley, Kevin M.; Hoshika, Shuichi; Frye, Carole; Benner, Steven A.

2015-01-01

Assays that target DNA or RNA (xNA) are highly sensitive, as small amounts of xNA can be amplified by PCR. Unfortunately, PCR is inconvenient in low resource environments, requiring equipment and power that may not be available in these environments. However, isothermal procedures that avoid thermal cycling are often confounded by primer dimers, off-target priming, and other artifacts. Here, we show how a “self avoiding molecular recognition system” (SAMRS) eliminates these artifacts to give clean amplicons in a helicase-dependent isothermal amplification (SAMRS-HDA). We also show that incorporating SAMRS into the 3′-ends of primers facilitates the design and screening of primers for HDA assays. Finally, we show that SAMRS-HDA can be twofold multiplexed, something difficult to achieve with HDA using standard primers. This shows that SAMRS-HDA is a more versatile approach than standard HDA with a broader applicability for xNA-targeted diagnostics and research. PMID:25953623

The Stellar IMF from Isothermal MHD Turbulence

Science.gov (United States)

Haugbølle, Troels; Padoan, Paolo; Nordlund, Åke

2018-02-01

We address the turbulent fragmentation scenario for the origin of the stellar initial mass function (IMF), using a large set of numerical simulations of randomly driven supersonic MHD turbulence. The turbulent fragmentation model successfully predicts the main features of the observed stellar IMF assuming an isothermal equation of state without any stellar feedback. As a test of the model, we focus on the case of a magnetized isothermal gas, neglecting stellar feedback, while pursuing a large dynamic range in both space and timescales covering the full spectrum of stellar masses from brown dwarfs to massive stars. Our simulations represent a generic 4 pc region within a typical Galactic molecular cloud, with a mass of 3000 M ⊙ and an rms velocity 10 times the isothermal sound speed and 5 times the average Alfvén velocity, in agreement with observations. We achieve a maximum resolution of 50 au and a maximum duration of star formation of 4.0 Myr, forming up to a thousand sink particles whose mass distribution closely matches the observed stellar IMF. A large set of medium-size simulations is used to test the sink particle algorithm, while larger simulations are used to test the numerical convergence of the IMF and the dependence of the IMF turnover on physical parameters predicted by the turbulent fragmentation model. We find a clear trend toward numerical convergence and strong support for the model predictions, including the initial time evolution of the IMF. We conclude that the physics of isothermal MHD turbulence is sufficient to explain the origin of the IMF.

Analysis of form deviation in non-isothermal glass molding

Science.gov (United States)

Kreilkamp, H.; Grunwald, T.; Dambon, O.; Klocke, F.

2018-02-01

Especially in the market of sensors, LED lighting and medical technologies, there is a growing demand for precise yet low-cost glass optics. This demand poses a major challenge for glass manufacturers who are confronted with the challenge arising from the trend towards ever-higher levels of precision combined with immense pressure on market prices. Since current manufacturing technologies especially grinding and polishing as well as Precision Glass Molding (PGM) are not able to achieve the desired production costs, glass manufacturers are looking for alternative technologies. Non-isothermal Glass Molding (NGM) has been shown to have a big potential for low-cost mass manufacturing of complex glass optics. However, the biggest drawback of this technology at the moment is the limited accuracy of the manufactured glass optics. This research is addressing the specific challenges of non-isothermal glass molding with respect to form deviation of molded glass optics. Based on empirical models, the influencing factors on form deviation in particular form accuracy, waviness and surface roughness will be discussed. A comparison with traditional isothermal glass molding processes (PGM) will point out the specific challenges of non-isothermal process conditions. Furthermore, the underlying physical principle leading to the formation of form deviations will be analyzed in detail with the help of numerical simulation. In this way, this research contributes to a better understanding of form deviations in non-isothermal glass molding and is an important step towards new applications demanding precise yet low-cost glass optics.

Isothermal crystallization and melting behavior of polypropylene/layered double hydroxide nanocomposites

International Nuclear Information System (INIS)

Lonkar, Sunil P.; Singh, R.P.

2009-01-01

The effect of layered double hydroxide (LDH) nanolayers on the crystallization behavior of polypropylene (PP) was studied based on the preparation of nanocomposites by a melt intercalation method. The isothermal crystallization kinetics and subsequent melting behavior of PP/LDH hybrids were studied with differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). Studies revealed that the LDH promoted heterogeneous nucleation, accelerating the crystallization of PP. The Avrami equation successfully describes the isothermal crystallization kinetics of PP/LDH hybrids and signifies heterogeneous nucleation in crystal growth of PP. The varying values of Avrami exponent (n) and half crystallization time (t 1/2 ) of PP and PP/LDH hybrids describes overall crystallization behavior. The crystallite size (D hkl ) and distribution of different crystallites in PP varied in presence of LDH. A significant increase in melting temperature is observed for PP/LDH hybrids. The POM showed that smaller and less perfect crystals were formed in nanocomposites because of molecular interaction between PP chains and LDH. The value of fold surface free energy (σ e ) of PP chains decreased with increasing LDH content. Finally, the overall results signify that LDH at nanometer level acted as nucleating agent and accelerate the overall crystallization process of PP.

Humidity scanning quartz crystal microbalance with dissipation monitoring setup for determination of sorption-desorption isotherms and rheological changes

Energy Technology Data Exchange (ETDEWEB)

Björklund, Sebastian, E-mail: sebastianbjorklund@gmail.com; Kocherbitov, Vitaly [Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden); Biofilms—Research Center for Biointerfaces, Malmö University, Malmö (Sweden)

2015-05-15

A new method to determine water sorption-desorption isotherms with high resolution in the complete range of water activities (relative humidities) is presented. The method is based on quartz crystal microbalance with dissipation monitoring (QCM-D). The QCM-D is equipped with a humidity module in which the sample film is kept in air with controlled humidity. The experimental setup allows for continuous scanning of the relative humidity from either dry to humid conditions or vice versa. The amount of water sorbed or desorbed from the sample is determined from the resonance frequencies of the coated quartz sensor, via analysis of the overtone dependence. In addition, the method allows for characterization of hydration induced changes of the rheological properties from the dissipation data, which is closely connected to the viscoelasticity of the film. The accuracy of the humidity scanning setup is confirmed in control experiments. Sorption-desorption isotherms of pig gastric mucin and lysozyme, obtained by the new method, show good agreement with previous results. Finally, we show that the deposition technique used to coat the quartz sensor influences the QCM-D data and how this issue can be used to obtain further information on the effect of hydration. In particular, we demonstrate that spin-coating represents an attractive alternative to obtain sorption-desorption isotherms, while drop-coating provides additional information on changes of the rheological properties during hydration.

Properties of cyclodextrins. V. Inclusion isotherm and kinetics of inclusion of benzoic acid and m-chlorobenzoic acid on b-E 25 cyclodextrin-epichlorohydrin resin

NARCIS (Netherlands)

Wiedenhof, N.; Trieling, R.G.

1971-01-01

The previous paper showed that b-E 25 resins have an affinity for aromatic compds., e.g. BZOH and m-ClC6H4CO2H; mainly the undissocd. acids are involved. The isothermal inclusion of undissocd. BZOH is described by a Langmuir isotherm, but that of m-ClC6H4CO2H follows a Freundlich isotherm. The

ISOTHERMAL AIR INGRESS VALIDATION EXPERIMENTS

Energy Technology Data Exchange (ETDEWEB)

Chang H Oh; Eung S Kim

2011-09-01

Idaho National Laboratory carried out air ingress experiments as part of validating computational fluid dynamics (CFD) calculations. An isothermal test loop was designed and set to understand the stratified-flow phenomenon, which is important as the initial air flow into the lower plenum of the very high temperature gas cooled reactor (VHTR) when a large break loss-of-coolant accident occurs. The unique flow characteristics were focused on the VHTR air-ingress accident, in particular, the flow visualization of the stratified flow in the inlet pipe to the vessel lower plenum of the General Atomic’s Gas Turbine-Modular Helium Reactor (GT-MHR). Brine and sucrose were used as heavy fluids, and water was used to represent a light fluid, which mimics a counter current flow due to the density difference between the stimulant fluids. The density ratios were changed between 0.87 and 0.98. This experiment clearly showed that a stratified flow between simulant fluids was established even for very small density differences. The CFD calculations were compared with experimental data. A grid sensitivity study on CFD models was also performed using the Richardson extrapolation and the grid convergence index method for the numerical accuracy of CFD calculations . As a result, the calculated current speed showed very good agreement with the experimental data, indicating that the current CFD methods are suitable for predicting density gradient stratified flow phenomena in the air-ingress accident.

Mathematical modelling of non-isothermal venturi scrubbers

Energy Technology Data Exchange (ETDEWEB)

Rahimi, A. [Isfahan Univ., Isfahan (Iran, Islamic Republic of). Dept. of Chemical Engineering; Taheri, M.; Fathikakajahi, J. [Shiraz Univ., Shiraz (Iran, Islamic Republic of). Dept. of Chemical Engineering

2005-06-01

Venturi scrubbers collect gaseous pollutants and particulate matter from industrial exhaust. This air pollution control device is highly efficient, easy to maintain and has a low initial cost. However, the high pressure drop through the device results in a high running cost. The main mechanism for collecting particulates is the inertial impaction of the particles on the droplets, which occurs due to high velocity between the gas stream and droplets. Droplet acceleration and irreversible drag-force which results from this high relative velocity are responsible for the high pressure drop in this type of scrubber. While several attempts have been made to mathematically model particulate removal in Venturi scrubbers, most models do not consider simultaneous heat and mass transfer. This factor is important because most Venturi scrubbers operate under non-isothermal conditions where the inlet gas is humidified in order to cool it before entering the scrubber. For that reason, the authors developed a more realistic model to determine the effects of heat and mass transfer on the particulate removal efficiency of a non-isothermal Venturi type scrubber. The model considers the effect of droplet size distribution and liquid film flow on the walls. It consists of differential equations for energy, momentum and material exchange. Model results were compared with data from experimental studies and industrial facilities. It was concluded that the removal efficiency of the scrubber is influenced by the inlet humidity temperature of the inlet gas. 26 refs., 1 tab., 10 figs.

THREE-DIMENSIONAL DISK-PLANET TORQUES IN A LOCALLY ISOTHERMAL DISK

International Nuclear Information System (INIS)

D'Angelo, Gennaro; Lubow, Stephen H.

2010-01-01

We determine an expression for the Type I planet migration torque involving a locally isothermal disk, with moderate turbulent viscosity (5 x 10 -4 ∼< α ∼< 0.05), based on three-dimensional nonlinear hydrodynamical simulations. The radial gradients (in a dimensionless logarithmic form) of density and temperature are assumed to be constant near the planet. We find that the torque is roughly equally sensitive to the surface density and temperature radial gradients. Both gradients contribute to inward migration when they are negative. Our results indicate that two-dimensional calculations with a smoothed planet potential, used to account for the effects of the third dimension, do not accurately determine the effects of density and temperature gradients on the three-dimensional torque. The results suggest that substantially slowing or stopping planet migration by means of changes in disk opacity or shadowing is difficult and appears unlikely for a disk that is locally isothermal. The scalings of the torque and torque density with planet mass and gas sound speed follow the expectations of linear theory. We also determine an improved formula for the torque density distribution that can be used in one-dimensional long-term evolution studies of planets embedded in locally isothermal disks. This formula can be also applied in the presence of mildly varying radial gradients and of planets that open gaps. We illustrate its use in the case of migrating super-Earths and determine some conditions sufficient for survival.

Tip-enhanced fluorescence with radially polarized illumination for monitoring loop-mediated isothermal amplification on Hepatitis C virus cDNA

Science.gov (United States)

Wei, Shih-Chung; Chuang, Tsung-Liang; Wang, Da-Shin; Lu, Hui-Hsin; Gu, Frank X.; Sung, Kung-Bin; Lin, Chii-Wann

2015-02-01

A tip nanobiosensor for monitoring DNA replication was presented. The effects of excitation power and polarization on tip-enhanced fluorescence (TEF) were assessed with the tip immersed in fluorescein isothiocyanate solution first. The photon count rose on average fivefold with radially polarized illumination at 50 mW. We then used polymerase-functionalized tips for monitoring loop-mediated isothermal amplification on Hepatitis C virus cDNA. The amplicon-SYBR Green I complex was detected and compared to real-time loop-mediated isothermal amplification. The signals of the reaction using 4 and 0.004 ng/μl templates were detected 10 and 30 min earlier, respectively. The results showed the potential of TEF in developing a nanobiosensor for real-time DNA amplification.

Non-isothermal curing kinetics and physical properties of MMT-reinforced unsaturated polyester (UP) resins

Energy Technology Data Exchange (ETDEWEB)

Vargas, María A., E-mail: angelesvh@yahoo.com [Tecnológico de Estudios Superiores de Ecatepec, Av. Tecnológico S/N, Valle de Anáhuac, 55210 Ecatepec de Morelos (Mexico); Vázquez, H. [Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Física, Av. San Rafael Atlixco 186, col. Vicentina, Mexico, D.F. 09340 (Mexico); Guthausen, G. [KIT, Pro2NMR at MVM and IBG, Karlsruhe (Germany)

2015-07-10

Highlights: • Non-isothermal DSC analysis results have shown that the addition of MMT to a UP resin produces a delay in the cure reaction. • The shape of experimental heat-flow DSC curves showed two exothermic peaks for all the samples at different heating rates. • The overall kinetic analysis was performed by isoconversional methods. • It was found that the dependence of the activation energy (E{sub a}) on degree of reaction (α) is complex. - Abstract: Cure behavior of unsaturated polyester (UP)/montmorillonite (MMT)/methyl ethyl ketone peroxide (MEKP)/cobalt octoate intercalated nanocomposites with various MMT loadings was investigated by dynamic differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). UP/MMT nanocomposites were prepared by sequential mixing. Non-isothermal DSC curves were obtained by applying heating rates ranging from 5 to 20 °C/min. They presented two exothermic peaks, which should correspond to two independent cure reactions. The effective activation energy E{sub a}, was determined by applying both the Kissinger’s and Starink’s methods. The results showed slightly higher activation energy for nanocomposites, except for UP/10-MMT. It was found that the dependence of E{sub a} on α is complex. All the systems in this study fitted Sesták–Berggren (SB) model in overall reaction controlled kinetics and the corresponding model parameters, n, m, A were obtained, but it was insufficient in depicting the complex reaction kinetics. Transmission electron microscopy data support the formation of a partially delaminated nanocomposite material. UP and nanocomposites showed similar behavior on thermal stability.

Isotherms and thermodynamics by linear and non-linear regression analysis for the sorption of methylene blue onto activated carbon: Comparison of various error functions

International Nuclear Information System (INIS)

Kumar, K. Vasanth; Porkodi, K.; Rocha, F.

2008-01-01

A comparison of linear and non-linear regression method in selecting the optimum isotherm was made to the experimental equilibrium data of methylene blue sorption by activated carbon. The r 2 was used to select the best fit linear theoretical isotherm. In the case of non-linear regression method, six error functions, namely coefficient of determination (r 2 ), hybrid fractional error function (HYBRID), Marquardt's percent standard deviation (MPSD), average relative error (ARE), sum of the errors squared (ERRSQ) and sum of the absolute errors (EABS) were used to predict the parameters involved in the two and three parameter isotherms and also to predict the optimum isotherm. For two parameter isotherm, MPSD was found to be the best error function in minimizing the error distribution between the experimental equilibrium data and predicted isotherms. In the case of three parameter isotherm, r 2 was found to be the best error function to minimize the error distribution structure between experimental equilibrium data and theoretical isotherms. The present study showed that the size of the error function alone is not a deciding factor to choose the optimum isotherm. In addition to the size of error function, the theory behind the predicted isotherm should be verified with the help of experimental data while selecting the optimum isotherm. A coefficient of non-determination, K 2 was explained and was found to be very useful in identifying the best error function while selecting the optimum isotherm

Adsorption isotherm special study. Final report

International Nuclear Information System (INIS)

1993-05-01

The study was designed to identify methods to determine adsorption applicable to Uranium Mill Tailings Remedial Action (UMTRA) Project sites, and to determine how changes in aquifer conditions affect metal adsorption, resulting retardation factors, and estimated contaminant migration rates. EPA and ASTM procedures were used to estimate sediment sorption of U, As, and Mo under varying groundwater geochemical conditions. Aquifer matrix materials from three distinct locations at the DOE UMTRA Project site in Rifle, CO, were used as the adsorbents under different pH conditions; these conditions stimulated geochemical environments under the tailings, near the tailings, and downgradient from the tailings. Grain size, total surface area, bulk and clay mineralogy, and petrography of the sediments were characterized. U and Mo yielded linear isotherms, while As had nonlinear ones. U and Mo were adsorbed strongly on sediments acidified to levels similar to tailings leachate. Changes in pH had much less effect on As adsorption. Mo was adsorbed very little at pH 7-7.3, U was weakly sorbed, and As was moderately sorbed. Velocities were estimated for metal transport at different pHs. Results show that the aquifer materials must be characterized to estimate metal transport velocities in aquifers and to develop groundwater restoration strategies for the UMTRA project

Non-isothermal crystallization kinetics and characterization of biodegradable poly(butylene succinate-co-neopentyl glycol succinate) copolyesters

International Nuclear Information System (INIS)

Xie, Wen-Jie; Zhou, Xiao-Ming

2015-01-01

Both biodegradable aliphatic neat poly(butylene succinate) (PBS) and poly(butylene succinate-co-neopentyl glycol succinate) (P(BS-co-NPGS)) copolyesters with different 1,4-butanediol/neopentyl glycol ratios were synthesized through a two-step process of transesterification and polycondensation using stannous chloride and 4-Methylbenzenesulfonic acid as the co-catalysts. The structure, non-isothermal crystallization behavior, crystalline morphology and crystal structure of neat PBS and P(BS-co-NPGS) copolyesters were characterized by 1 H NMR, differential scanning calorimetry (DSC), polarized optical microscope (POM) and wide angle X-ray diffraction (WAXD), respectively. The Avrami equation modified by Jeziorny and Mo's method was employed to describe the non-isothermal crystallization kinetics of the neat PBS and its copolyesters. The modified Avrami equation could adequately describe the primary stage of non-isothermal crystallization kinetics of the neat PBS and its copolyesters. Mo's method provided a fairly satisfactory description of the non-isothermal crystallization of neat PBS and its copolyesters. Interestingly, the values of 1/t 1/2 , Z c and F(T) obtained by the modified Avrami equation and Mo's method analysis indicated that the crystallization rate increased first and then decreased with an increase of NPGS content compared that of neat PBS, whereas the crystallization mechanism almost kept unchanged. The results of tensile testing showed that the ductility of PBS was largely improved by incorporating NPGS units. The elongation at break increased remarkably with increasing NPGS content. In particular, the sample with 20% NPGS content showed around 548% elongation at break. - Highlights: • The incorporation of NPGS units reduced the spherulite size of BS unit. • The existence of NPGS units did not change the crystal structure of BS unit. • The NPGS units incorporated in PBS could significantly improve the ductility of PBS. • The

Assessment of precipitates of isothermal aged austenitic stainless steel using measurement techniques of ultrasonic attenuation

International Nuclear Information System (INIS)

Kim, Hun Hee; Kim, Hak Joon; Song, Sung Jin; Lim, Byeong Soo; Kim, Kyung Cho

2014-01-01

AISI 316L stainless steel is widely used as a structural material of high temperature thermoelectric power plants, since austenitic stainless steel has excellent mechanical properties. However, creep damage is generated in these components, which are operated under a high temperature and high pressure environment. Several researches have been done on how microstructural changes of precipitates affect to the macroscopic mechanical properties. And they investigate the relation between ultrasonic parameters and metallurgical results. But, these studies are limited by experiment results only. In this paper, attenuations of ultrasonic with isothermal damaged AISI 316L stainless steel were measured. Also, simulation of ultrasonic attenuation with variation of area fraction and size of precipitates were performed. And, from the measured attenuations, metallographic data and simulation results, we investigate the relations between the ultrasonic attenuations and the material properties which is area fraction of precipitates for the isothermal damaged austenitic stainless steel specimens. And, we studied parametric study for investigation of the relation between ultrasonic parameters and metallurgical results of the isothermal damaged AISI 316L stainless steel specimens using numerical methods.

Lunar ash flows - Isothermal approximation.

Science.gov (United States)

Pai, S. I.; Hsieh, T.; O'Keefe, J. A.

1972-01-01

Suggestion of the ash flow mechanism as one of the major processes required to account for some features of lunar soil. First the observational background and the gardening hypothesis are reviewed, and the shortcomings of the gardening hypothesis are shown. Then a general description of the lunar ash flow is given, and a simple mathematical model of the isothermal lunar ash flow is worked out with numerical examples to show the differences between the lunar and the terrestrial ash flow. The important parameters of the ash flow process are isolated and analyzed. It appears that the lunar surface layer in the maria is not a residual mantle rock (regolith) but a series of ash flows due, at least in part, to great meteorite impacts. The possibility of a volcanic contribution is not excluded. Some further analytic research on lunar ash flows is recommended.

Adsorption of an anionic dye on a novel low-cost mesoporous adsorbent: kinetic, thermodynamic and isotherm studies

Science.gov (United States)

Msaad, Asmaa; Belbahloul, Mounir; Zouhri, Abdeljalil

2018-05-01

Our activated carbon was prepared successfully using phosphoric acid as an activated agent. The activated carbon was characterized by Scanning Electron Micrograph (SEM), Brunauer-Emmett- Teller (BET), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The aim of our study is to evaluate the adsorption capacity of Methyl Orange (MO) on Ziziphus lotus activated carbon. Adsorption isotherms were studied according to Langmuir and Freundlich Model, and adsorption kinetics according to pseudo-first and second-order. Results show that the maximum adsorption was reached in the first 10min at ambient temperature with a yield of 96.31%. The Langmuir isotherm shows a correlation coefficient of 99.4 % higher than Freundlich model and the adsorption kinetic model follow a pseudo-second-order with a maximum adsorption capacity of 769.23 mg/g. FTIR and X-Ray spectroscopy indicate that our activated carbon has an amorphous structure with the presence of functional groups, where BET analysis revealed a high surface area of 553 mg/g, which facilitate the adsorption process

Adsorption of cationic surfactants on silica surface: 1. Adsorption isotherms and surface charge

NARCIS (Netherlands)

Goloub, T.P.; Koopal, L.K.; Sidorova, M.P.

2004-01-01

Adsorption isotherms of cationic surfactant, dodecylpyridinium chloride, on an Aerosil OX50 and isotherms of surface charge against the background of 0.001- and 0.1-M KCl solutions at pH 7 and 9 were measured and analyzed. Different forms of adsorption isotherms of surfactants at low and high

Fuel concentration in isothermal Diesel sprays through structured planar laser imaging measurements

Energy Technology Data Exchange (ETDEWEB)

Payri, R.; Gimeno, J.; Marti, P. [CMT Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Manin, J., E-mail: jmanin@sandia.gov [Sandia National Laboratories, 7011 East Ave., 94551 Livermore, CA (United States)

2012-04-15

Highlights: Black-Right-Pointing-Pointer Structured illumination has been implemented to quantify mixing in isothermal sprays. Black-Right-Pointing-Pointer Comparison to a gas-jet model conducted to Schmidt number below the unity (Sc = 0.8). Black-Right-Pointing-Pointer Results showed incomplete momentum transfer due to velocity slip between droplets and ambient. Black-Right-Pointing-Pointer Higher injection pressures enhance momentum transfer and lead to better global mixing. - Abstract: The mixing of isothermal liquid sprays in engine-like conditions has been investigated by applying the structured planar laser imaging technique to remove multiple light scattering. The intensity of the illumination plane has been recovered by removing multiply scattered light and mapping the spray three-dimensionally via discrete tomography. Based on the extinction of light within the illumination plane, the number density has been extracted. Coupled with 2-D maps of droplet diameters obtained through LIF/Mie ratio, the number density allowed to calculate the fuel concentration in the sprays. The mixture fraction of DI Diesel sprays injected into an inert environment held at room temperature has been evaluated and compared to a 2-D model based on gas-jet theory. The experimental results showed good agreement with the predictions when a Gaussian radial distribution is assumed and the Schmidt number is correctly tuned. Differences in the radial distribution has been observed and related to incomplete momentum transfer between the liquid spray and the surrounding gases. For different testing conditions, while the influence of ambient density on mixing was expected, the effect of injection pressure has been found to provide additional information concerning the global mixing of liquid sprays.

Non-isothermal crystallization kinetics of As{sub 30}Te{sub 60}Ga{sub 10} glass

Energy Technology Data Exchange (ETDEWEB)

Mohamed, Mansour; Abd-Elnaiem, Alaa M.; Abdel-Rahim, M.A.; Hafiz, M.M. [Assiut University, Physics Department, Faculty of Science, Assiut (Egypt); Hassan, R.M. [Assiut University, Physics Department, Faculty of Science, Assiut (Egypt); Aden University, Physics Department, Faculty of Education-Zingiber, Aden (Yemen)

2017-08-15

The crystallization study under non-isothermal conditions of As{sub 30}Te{sub 60}Ga{sub 10} glass was investigated. The studied composition was synthesized by melt-quenching technique and characterized by different techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The XRD analysis revealed that the as-prepared and annealed bulk glass of As{sub 30}Te{sub 60}Ga{sub 10} exhibit the amorphous, and polycrystalline nature, respectively. The DSC results showed that the heating rate affects the characteristic temperatures, for instance, the glass transition, onset, and peak crystallization temperatures. Furthermore, some thermal analysis methods such as the Kissinger and Matusita et al., approximations were employed to determine the crystallization parameters: for example Avrami exponent and the activation energies for glass transition and crystallization process. In addition, we have compared the experimental DSC data with the calculated ones based on the Johnson-Mehl-Avrami (JMA) and Sestak-Berggren SB(M,N) models. The results indicated that the SB(M,N) model is more suitable for describing the non-isothermal crystallization kinetics of the investigated composition. (orig.)

300 K Isothermal Equations of State of DADNE, DNAN, and LX-17

Science.gov (United States)

Zaug, Joseph; Stavrou, Elissaios; Grivickas, Paulius; Pagoria, Phil; Hansen, Donald; Gagliardi, Franco; Sain, John; Bastea, Sorin

2017-06-01

Using a direct optical-based measurement approach, we report 10 GPa scale, 300 K isothermal equations of state (EOS) of single crystal 1,1-Diamino-2,2-dinitroethylene (DADNE, FOX-7), single crystal 2,4, Dintrosoanisole (DNAN) and a polymer blended explosive (PBX) composite LX-17 (92.5% triamino trinitro benzene (TATB), and 7.5% KEL-F 800). Results from quasi-statically compressed LX-17 represent the first-ever isothermal EOS measurements of a PBX. Recently, we published a paper outlining the utility of using in-house optical microscopy and interferometry (OMI) diagnostics to directly measure pressure dependent sample volumes of single crystals TATB and alpha-NTO compressed within diamond-anvil cell sample chambers. (Our TATB OMI results agree remarkably well with two independent powder x-ray diffraction EOS studies.) In addition, here we report single crystal pressure dependent indices of refraction from DADNE that clearly signal the onset of electronic and/or molecular (structural) transitions that are otherwise indistinguishable in 300 K plotted pressure-volume EOS isotherms. EOS model parameters are reported from weighted and unweighted fits to the OMI experimental data. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

Sorption isotherms: A review on physical bases, modeling and measurement

Energy Technology Data Exchange (ETDEWEB)

Limousin, G. [Atomic Energy Commission, Tracers Technology Laboratory, 38054 Grenoble Cedex (France) and Laboratoire d' etude des Transferts en Hydrologie et Environnement (CNRS-INPG-IRD-UJF), BP 53, 38041 Grenoble Cedex (France)]. E-mail: guillaumelimousin@yahoo.fr; Gaudet, J.-P. [Laboratoire d' etude des Transferts en Hydrologie et Environnement (CNRS-INPG-IRD-UJF), BP 53, 38041 Grenoble Cedex (France); Charlet, L. [Laboratoire de Geophysique Interne et Techtonophysique - CNRS-IRD-LCPC-UJF-Universite de Savoie, BP 53, 38041 Grenoble Cedex (France); Szenknect, S. [Atomic Energy Commission, Tracers Technology Laboratory, 38054 Grenoble Cedex (France); Barthes, V. [Atomic Energy Commission, Tracers Technology Laboratory, 38054 Grenoble Cedex (France); Krimissa, M. [Electricite de France, Division Recherche et Developpement, Laboratoire National d' Hydraulique et d' Environnement - P78, 6 quai Watier, 78401 Chatou (France)

2007-02-15

The retention (or release) of a liquid compound on a solid controls the mobility of many substances in the environment and has been quantified in terms of the 'sorption isotherm'. This paper does not review the different sorption mechanisms. It presents the physical bases underlying the definition of a sorption isotherm, different empirical or mechanistic models, and details several experimental methods to acquire a sorption isotherm. For appropriate measurements and interpretations of isotherm data, this review emphasizes 4 main points: (i) the adsorption (or desorption) isotherm does not provide automatically any information about the reactions involved in the sorption phenomenon. So, mechanistic interpretations must be carefully verified. (ii) Among studies, the range of reaction times is extremely wide and this can lead to misinterpretations regarding the irreversibility of the reaction: a pseudo-hysteresis of the release compared with the retention is often observed. The comparison between the mean characteristic time of the reaction and the mean residence time of the mobile phase in the natural system allows knowing if the studied retention/release phenomenon should be considered as an instantaneous reversible, almost irreversible phenomenon, or if reaction kinetics must be taken into account. (iii) When the concentration of the retained substance is low enough, the composition of the bulk solution remains constant and a single-species isotherm is often sufficient, although it remains strongly dependent on the background medium. At higher concentrations, sorption may be driven by the competition between several species that affect the composition of the bulk solution. (iv) The measurement method has a great influence. Particularly, the background ionic medium, the solid/solution ratio and the use of flow-through or closed reactor are of major importance. The chosen method should balance easy-to-use features and representativity of the studied

Isothermality of the gas in the Coma cluster

International Nuclear Information System (INIS)

Hughes, J.P.; Yamashita, K.; Okumura, Y.; Tsunemi, H.; Matsuoka, M.

1988-01-01

The high-quality X-ray spectrum of the Coma cluster observed by the Japanese satelite Tenma in conjunction with imaging data from the Einstein Observatory was used to explore the temperature distribution of the cluster gas. It is found that pure polytropic models are inadequate to describe this temperature distribution. Instead, a hybrid model is proposed consisting of a central isothermal region surrounded by a polytropic distribution. It is shown that as much as 75 percent of the global emission may come from the isothermal component. 30 references

Negative Saturation Approach for Non-Isothermal Compositional Two-Phase Flow Simulations

NARCIS (Netherlands)

Salimi, H.; Wolf, K.H.; Bruining, J.

2011-01-01

This article deals with developing a solution approach, called the non-isothermal negative saturation (NegSat) solution approach. The NegSat solution approach solves efficiently any non-isothermal compositional flow problem that involves phase disappearance, phase appearance, and phase transition.

Sorption of Pb2+ from Aqueous Solution unto Modified Rice Husk: Isotherms Studies

Directory of Open Access Journals (Sweden)

A. O. Dada

2013-01-01

Full Text Available Investigation of the sorption potential of rice husk, an agricultural waste, as an adsorbent was carried out. The rice husk was modified with orthophosphoric acid and was used for adsorption of lead (II ions (Pb2+ from aqueous solution. Physicochemical properties of the modified rice husk were determined. Equilibrium sorption data were confirmed with Langmuir, Freundlich and Temkin adsorption isotherms. On the basis of adsorption isotherm graphs, R2 values were determined to be 0.995, 0.916, and 0.797 for Langmuir, Temkin, and Freundlich isotherms, respectively, indicating that the data fitted well into the adsorption isotherms, but Langmuir isotherm is a better model. The maximum monolayer coverage from Langmuir studies, Qmax=138.89 mg/g, Langmuir isotherm constant, KL=0.699 L/mg, and the separation factor, RL=1.41×10−2 at 100 mg/L of lead(II ions indicating that the sorption process, was favourable. The suitability of modified rice husk as an adsorbent for the removal of lead ions from aqueous solution and its potential for pollution control is established.

Experimental study of a laboratory concrete material representative of containment buildings: desorption isotherms and permeability determination

International Nuclear Information System (INIS)

Semete, P.; Fevrier, B.; Delorme, J.; Sanahuja, J.; Desgree, P.; Le Pape, Y.

2015-01-01

The isotherm sorption curve is a first order parameter for the calculations of concrete drying and/or creep using Finite Element Analysis. An experimental campaign was undertaken by EDF MMC in order to characterize the first desorption isotherm at room temperature of a laboratory material representative of concrete containment buildings. Long term drying tests were carried out on cement paste and on three samples geometries on concrete (with radial and axial one-dimensional drying on thin disks and multi-dimensional drying on Representative Elementary Volumes). The measurements results (porosity, densities and mass loss curves) are provided and the isotherms obtained for the four different configurations are compared. Several analyses of the results are proposed including the assessment of a criterion for the determination of the moisture content final balance (estimation of the asymptotic mass loss) and the back-analysis of equivalent permeability. (authors)

Influence of isothermal thermomechanical treatment on structure and properties of structural steels

International Nuclear Information System (INIS)

Smirnov, M.A.; Kaletin, A.Yu.; Schastlivthev, V.M.; Kaletina, Yu.V.

1997-01-01

A study is made into the structure and mechanical properties of steel 35KhGSA and 37KhN3A after isothermal hardening resulting in bainitic structure formation as well as after low-temperature thermomechanical treatment (LTTMT) combining the plastic deformation at the temperature of bainitic transformation and subsequent isothermal hardening. It is shown that LTTMT permits and essential enhancement of strength properties in steel 35KhGSA, high plasticity and impact strength being reserved. This is associated with bainitic structure refinement. In steel 37KhN3A the process of carbide formation takes place along with bainitic transformation, and LTTMT results in lesser strengthening. LTTMT is fount to not practically affect the tendency of structural steels to bainitic brittleness. This treatment promotes some shift of brittleness manifestation to lower temperatures

Isothermal and isochronal annealing experiments on irradiated commercial power VDMOSFETs

International Nuclear Information System (INIS)

Jaksic, A.B.; Pejovic, M.M.; Ristic, G.S.

1999-01-01

The paper presents results of isothermal and isochronal annealing experiments on several types of gamma-ray irradiated commercial N- and P-channel power VDMOSFETs. Transistors were characterized for their threshold voltage shift and densities of radiation-induced oxide-trap charge and interface traps. The results show that the temperature enhances interface trap formation and oxide-trap charge decay rates, but also contributes to the passivation of interface traps. The study demonstrates that formation and passivation of interface traps are simultaneous processes. At certain conditions (lower temperature and/or positive bias) interface-trap formation dominates. Oppositely, at other conditions (higher temperature and/or negative bias) passivation is predominant. However at some conditions there is a complex interplay between formation and passivation of interface traps, resulting in interface traps increase followed by decrease at later annealing times. No model for interface trap post-irradiation behavior can explain this effect better than the recently proposed H-W model

Relation between Tolman length and isothermal compressibility for simple liquids

International Nuclear Information System (INIS)

Wang Xiao-Song; Zhu Ru-Zeng

2013-01-01

The Tolman length δ 0 of a liquid with a plane surface has attracted increasing theoretical attention in recent years, but the expression of Tolman length in terms of observable quantities is still not very clear. In 2001, Bartell gave a simple expression of Tolman length δ 0 in terms of isothermal compressibility. However, this expression predicts that Tolman length is always negative, which is contrary to the results of molecular dynamics simulations (MDS) for simple liquids. In this paper, this contradiction is analyzed and the reason for the discrepancy in the sign is found. In addition, we introduce a new expression of Tolman length in terms of isothermal compressibility for simple fluids not near the critical points under some weak restrictions. The Tolman length of simple liquids calculated by using this formula is consistent with that obtained using MDS regarding the sign

Lattice Boltzmann method for weakly ionized isothermal plasmas

International Nuclear Information System (INIS)

Li Huayu; Ki, Hyungson

2007-01-01

In this paper, a lattice Boltzmann method (LBM) for weakly ionized isothermal plasmas is presented by introducing a rescaling scheme for the Boltzmann transport equation. Without using this rescaling, we found that the nondimensional relaxation time used in the LBM is too large and the LBM does not produce physically realistic results. The developed model was applied to the electrostatic wave problem and the diffusion process of singly ionized helium plasmas with a 1-3% degree of ionization under an electric field. The obtained results agree well with theoretical values

Desorption isotherms, drying characteristics and qualities of glace tropical fruits undergoing forced convection solar drying

Energy Technology Data Exchange (ETDEWEB)

Jamradloedluk, Jindaporn; Wiriyaumpaiwong, Songchai [Mahasarakham Univ. Khamriang, Kantarawichai, Mahasarakham (Thailand)

2008-07-01

Solar energy, a form of sustainable energy, has a great potential for a wide variety of applications because it is abundant and accessible, especially for countries located in the tropical region. Drying process is one of the prominent techniques for utilization of solar energy. This research work proposes a forced convection solar drying of osmotically pretreated fruits viz. mango, guava, and pineapple. The fruit cubes with a dimension of 1cm x 1cm x 1cm were immersed in 35% w./w. sucrose solution prior to the drying process. Drying kinetics, color and hardness of the final products obtained from solar drying were investigated and compared with those obtained from open air-sun drying. Desorption isotherms of the osmosed fruits were also examined and five mathematical models were used to fit the desorption curves. Experimental results revealed that solar drying provided higher drying rate than natural sun drying. Color of glace fruit processed by solar drying was more intense, indicated by lower value of lightness and higher value of yellowness, than that processed by sun drying. Hardness of the products dehydrated by both drying methods, however, was not significantly different (p>0.05). Validation of the mathematical models developed showed that the GAB model was most effective for describing desorption isotherms of osmotically pretreated mango and pineapple whereas Peleg's model was most effective for describing desorption isotherms of osmotically pretreated guava. (orig.)

Tunneling in cosmology and isothermal inflation

International Nuclear Information System (INIS)

Brout, R.; Spindel, P.

1991-01-01

The wave function for the universe, as proposed by Hartle and Hawking, experiences tunneling for small values of the radius of the universe. This induces thermal effects and so a hot big bang. We first give a detailed analysis of the observer accelerating in Minkowski space in terms of the tunneling of his wave function beyond his turning point. Applied to cosmology one finds a temperature at the big bang equal to the Gibbons-Hawking value. The residual thermal effects which result in an isothermal inflationary expansion give rise to a renormalized self-consistently determined Hubble constant (and hence Gibbons-Hawking temperature) through the trace anomaly. A thermodynamic interpretation is given. These results militate against phase transitions as a motor for inflation. (orig.)

Evolution of the Cerro Prieto geothermal system as interpreted from vitrinite reflectance under isothermal conditions

Energy Technology Data Exchange (ETDEWEB)

Barker, C.E. (US Geological Survey, Denver, CO); Pawlewicz, M.J.; Bostick, N.H.; Elders, W.A.

1981-01-01

Temperature estimates from reflectance data in the Cerro Prieto system correlate with modern temperature logs and temperature estimates from fluid inclusion and oxygen isotope geothermometry indicating that the temperature in the central portion of the Cerro Prieto System is now at its historical maximum. Isoreflectance lines formed by contouring vitrinite reflectance data for a given isothermal surface define an imaginary surface that indicates an apparent duration of heating in the system. The 250/sup 0/C isothermal surface has a complex dome-like form suggesting a localized heat source that has caused shallow heating in the central portion of this system. Isoreflectance lines relative to this 250/sup 0/C isothermal surface define a zone of low reflectance roughly corresponding to the crest of the isothermal surface. Comparison of these two surfaces suggest that the shallow heating in the central portion of Cerro Prieto is young relative to the heating (to 250/sup 0/C) on the system margins. Laboratory and theoretical models of hydrothermal convection cells suggest that the form of the observed 250/sup 0/C isothermal surface and the reflectance surface derived relative to it results from the convective rise of thermal fluids under the influence of a regional hydrodynamic gradient that induces a shift of the hydrothermal heating effects to the southwest.

Helicase-Dependent Isothermal Amplification of DNA and RNA by Using Self-Avoiding Molecular Recognition Systems.

Science.gov (United States)

Yang, Zunyi; McLendon, Chris; Hutter, Daniel; Bradley, Kevin M; Hoshika, Shuichi; Frye, Carole B; Benner, Steven A

2015-06-15

Assays that detect DNA or RNA (xNA) are highly sensitive, as small amounts of xNA can be amplified by PCR. Unfortunately, PCR is inconvenient in low-resource environments, and requires equipment and power that might not be available in these environments. Isothermal procedures, which avoid thermal cycling, are often confounded by primer dimers, off-target priming, and other artifacts. Here, we show how a "self avoiding molecular recognition system" (SAMRS) eliminates these artifacts and gives clean amplicons in a helicase-dependent isothermal amplification (SAMRS-HDA). We also show that incorporating SAMRS into the 3'-ends of primers facilitates the design and screening of primers for HDA assays. Finally, we show that SAMRS-HDA can be twofold multiplexed, difficult to achieve with HDA using standard primers. Thus, SAMRS-HDA is a more versatile approach than standard HDA, with a broader applicability for xNA-targeted diagnostics and research. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water adsorption isotherms and thermodynamic properties of cassava bagasse

International Nuclear Information System (INIS)

Polachini, Tiago Carregari; Betiol, Lilian Fachin Leonardo; Lopes-Filho, José Francisco; Telis-Romero, Javier

2016-01-01

Highlights: • Adsorption isotherms and composition of cassava bagasse were determined. • GAB equation was the best-fitted model to sorption data of type II isotherm. • Isosteric heat of sorption was calculated in a range of equilibrium moisture content. • Differential enthalpy and entropy confirmed the isokinetic compensation theory. • Water adsorption by cassava bagasse is considered an enthalpy driven process. - Abstract: Losses of food industry are generally wet products that must be dried to posterior use and storage. In order to optimize drying processes, the study of isotherms and thermodynamic properties become essential to understand the water sorption mechanisms of cassava bagasse. For this, cassava bagasse was chemically analyzed and had its adsorption isotherms determined in the range of 293.15–353.15 K through the static gravimetric method. The models of GAB, Halsey, Henderson, Oswin and Peleg were fitted, and best adjustments were found for GAB model with R"2 > 0.998 and no pattern distribution of residual plots. Isosteric heat of adsorption and thermodynamic parameters could be determined as a function of moisture content. Compensation theory was confirmed, with linear relationship between enthalpy and entropy and higher values of isokinetic temperature (T_B = 395.62 K) than harmonic temperature. Water adsorption was considered driven by enthalpy, clarifying the mechanisms of water vapor sorption in cassava bagasse.

Calculation of recovery plasticity in multistage hot forging under isothermal conditions.

Science.gov (United States)

Zhbankov, Iaroslav G; Perig, Alexander V; Aliieva, Leila I

2016-01-01

A widely used method for hot forming steels and alloys, especially heavy forging, is the process of multistage forging with pauses between stages. The well-known effect which accompanies multistage hot forging is metal plasticity recovery in comparison with monotonic deformation. A method which takes into consideration the recovery of plasticity in pauses between hot deformations of a billet under isothermal conditions is proposed. This method allows the prediction of billet forming limits as a function of deformation during the forging stage and the duration of the pause between the stages. This method takes into account the duration of pauses between deformations and the magnitude of subdivided deformations. A hot isothermal upsetting process with pauses was calculated by the proposed method. Results of the calculations have been confirmed with experimental data.

Isothermal Gravitational Segregation: Algorithms and Specifications

DEFF Research Database (Denmark)

Halldórsson, Snorri; Stenby, Erling Halfdan

2000-01-01

New algorithms for calculating the isothermal equilibrium state of reservoir fluids under the influence of gravity are presented. Two types of specifications are considered: the specification of pressure and composition at a reference depth; and the specification of the total overall content of t...

Gas adsorption on commercial magnesium stearate: Effects of degassing conditions on nitrogen BET surface area and isotherm characteristics.

Science.gov (United States)

Lapham, Darren P; Lapham, Julie L

2017-09-15

Commercial grades of magnesium stearate have been analysed by nitrogen adsorption having been pre-treated at temperatures between 30°C and 110°C and in the as-received state. Characteristics of nitrogen adsorption/desorption isotherms are assessed through the linearity of low relative pressure isotherm data and the BET transform plot together with the extent of isotherm hysteresis. Comparison is made between thermal gravimetric analysis and mass loss on drying. Features of gas adsorption isotherms considered atypical are identified and possible causes presented. It is shown that atypical isotherm features and issues of applying BET theory to the calculation of S BET are linked to the presence of hydrated water and that these depend on the hydration state: being more pronounced for the di-hydrate than the mono-hydrate. Dehydration reduces the extent of atypical features. S BET of a mono-hydrate sample is 5.6m 2 g -1 and 3.2m 2 g -1 at 40°C and 100°C degassing respectively but 23.9m 2 g 1 and 5.9m 2 g -1 for di-hydrate containing samples under comparable degassing. Di-hydrated samples also show S BET >15m 2 g 1 , BET C-values adsorption data. Copyright © 2017 Elsevier B.V. All rights reserved.

Water adsorption isotherms of carboxymethyl cellulose, guar, locust bean, tragacanth and xanthan gums.

Science.gov (United States)

Torres, María D; Moreira, Ramón; Chenlo, Francisco; Vázquez, María J

2012-06-20

Water adsorption isotherms of carboxymethyl cellulose (CMC), guar gum (GG), locust bean gum (LBG), tragacanth gum (TG) and xanthan gum (XG) were determined at different temperatures (20, 35, 50, and 65°C) using a gravimetric method. Several saturated salt solutions were selected to obtain different water activities in the range from 0.09 to 0.91. Water adsorption isotherms of tested hydrocolloids were classified like type II isotherms. In all cases, equilibrium moisture content decreased with increasing temperature at each water activity value. Three-parameter Guggenheim-Anderson-de Boer (GAB) model was employed to fit the experimental data in the water activity range and statistical analysis indicated that this model gave satisfactory results. CMC and GG were the most and the least hygroscopic gums, respectively. Sorption heats decreased with increasing moisture content. Monolayer moisture content evaluated with GAB model was consistent with equilibrium conditions of maximum stability calculated from thermodynamic analysis of net integral entropy. Values of equilibrium relative humidity at 20°C are proposed to storage adequately the tested gums. Copyright © 2012 Elsevier Ltd. All rights reserved.

Desorption isotherms and mathematical modeling of thin layer drying kinetics of tomato

Science.gov (United States)

Belghith, Amira; Azzouz, Soufien; ElCafsi, Afif

2016-03-01

In recent years, there is an increased demand on the international market of dried fruits and vegetables with significant added value. Due to its important production, consumption and nutrient intake, drying of tomato has become a subject of extended and varied research works. The present work is focused on the drying behavior of thin-layer tomato and its mathematical modeling in order to optimize the drying processes. The moisture desorption isotherms of raw tomato were determined at four temperature levels namely 45, 50, 60 and 65 °C using the static gravimetric method. The experimental data obtained were modeled by five equations and the (GAB) model was found to be the best-describing these isotherms. The drying kinetics were experimentally investigated at 45, 55 and 65 °C and performed at air velocities of 0.5 and 2 m/s. In order to investigate the effect of the exchange surface on drying time, samples were dried into two different shapes: tomato halves and tomato quarters. The impact of various drying parameters was also studied (temperature, air velocity and air humidity). The drying curves showed only the preheating period and the falling drying rate period. In this study, attention was paid to the modeling of experimental thin-layer drying kinetics. The experimental results were fitted with four different models.

Characterization of bainitic/martensitic structures formed in isothermal treatments below the M

NARCIS (Netherlands)

Navarro Lopez, A.; Hidalgo Garcia, J.; Sietsma, J.; Santofimia Navarro, M.J.

2017-01-01

Advanced Multiphase High Strength Steels are generally obtained by applying isothermal treatments around the martensite start temperature (M_s). Previous investigations have shown that bainitic ferrite can form from austenite in isothermal treatments below M_s, where its

Isothermal multiple displacement amplification: a methodical approach enhancing molecular routine diagnostics of microcarcinomas and small biopsies

Directory of Open Access Journals (Sweden)

Mairinger FD

2014-08-01

Full Text Available Fabian D Mairinger,1 Robert FH Walter,2 Claudia Vollbrecht,3 Thomas Hager,1 Karl Worm,1 Saskia Ting,1 Jeremias Wohlschläger,1 Paul Zarogoulidis,4 Konstantinos Zarogoulidis,4 Kurt W Schmid1 1Institute of Pathology, 2Ruhrlandklinik, West German Lung Center, University Hospital Essen, Essen, 3Institute of Pathology, University Hospital Cologne, Cologne, Germany; 4Pulmonary Department, Oncology Unit, G Papanikolaou General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece Background and methods: Isothermal multiple displacement amplification (IMDA can be a powerful tool in molecular routine diagnostics for homogeneous and sequence-independent whole-genome amplification of notably small tumor samples, eg, microcarcinomas and biopsies containing a small amount of tumor. Currently, this method is not well established in pathology laboratories. We designed a study to confirm the feasibility and convenience of this method for routine diagnostics with formalin-fixed, paraffin-embedded samples prepared by laser-capture microdissection. Results: A total of 250 µg DNA (concentration 5 µg/µL was generated by amplification over a period of 8 hours with a material input of approximately 25 cells, approximately equivalent to 175 pg of genomic DNA. In the generated DNA, a representation of all chromosomes could be shown and the presence of elected genes relevant for diagnosis in clinical samples could be proven. Mutational analysis of clinical samples could be performed without any difficulty and showed concordance with earlier diagnostic findings. Conclusion: We established the feasibility and convenience of IMDA for routine diagnostics. We also showed that small amounts of DNA, which were not analyzable with current molecular methods, could be sufficient for a wide field of applications in molecular routine diagnostics when they are preamplified with IMDA. Keywords: isothermal multiple displacement amplification, isothermal, whole

Moisture sorption isotherms and thermodynamic properties of bovine leather

Science.gov (United States)

Fakhfakh, Rihab; Mihoubi, Daoued; Kechaou, Nabil

2018-04-01

This study was aimed at the determination of bovine leather moisture sorption characteristics using a static gravimetric method at 30, 40, 50, 60 and 70 °C. The curves exhibit type II behaviour according to the BET classification. The sorption isotherms fitting by seven equations shows that GAB model is able to reproduce the equilibrium moisture content evolution with water activity for moisture range varying from 0.02 to 0.83 kg/kg d.b (0.9898 thermodynamic properties such as isosteric heat of sorption, sorption entropy, spreading pressure, net integral enthalpy and entropy. Net isosteric heat of sorption and differential entropy were evaluated through direct use of moisture isotherms by applying the Clausius-Clapeyron equation and used to investigate the enthalpy-entropy compensation theory. Both sorption enthalpy and entropy for desorption increase to a maximum with increasing moisture content, and then decrease sharply with rising moisture content. Adsorption enthalpy decreases with increasing moisture content. Whereas, adsorption entropy increases smoothly with increasing moisture content to a maximum of 6.29 J/K.mol. Spreading pressure increases with rising water activity. The net integral enthalpy seemed to decrease and then increase to become asymptotic. The net integral entropy decreased with moisture content increase.

Effect of aspect ratio on natural convective heat transfer adjacent to a vertival isothermal cylinder immersed in pure water

International Nuclear Information System (INIS)

Riu, Kap Jong; Eum, Yong Kyoon; Park, Sung Soon

1990-01-01

A numerical analysis is performed about the effect of aspect ratio on heat transfer adjacent to a vertical-isothermal cylinder of 0 deg C in pure water. The numerical results for the effect of aspect ratio are presented for ambient water temperature from 1.0 deg C to 15.0 deg C. They include velocity profiles, temperature profiles and mean Nusselt number for the entire flow field. The mean Nusselt numbers of vertival-isothermal cylinder are compared with that of vertival-isothermal plate in increasing aspect ratio of cylinder. Furthermore, the mean Nusselt numbers of unsteady region in the range of 0.084< R<0.328 are obtained by curve-fitting. The natural convection caused by phase change was investigated by experiments when the vertical ice cylinder was immersed in the pure water of which the tempetature range is from 2.0 to 10.0 deg C. Each figure shows a time-exposure photograph of flow occuring at the respective ambient water temperature conditions. As the ambient water temperature is increased from 2.0 to 10.0 deg C, the regimes of upward steady state flows, steady state dual flows and downward steady state flows are observed. Also, the variations of shapes of melting ice cylinder are investigated.(Author)

Thermodynamics of Surfactants, Block Copolymers and Their Mixtures in Water: The Role of the Isothermal Calorimetry

Science.gov (United States)

De Lisi, Rosario; Milioto, Stefania; Muratore, Nicola

2009-01-01

The thermodynamics of conventional surfactants, block copolymers and their mixtures in water was described to the light of the enthalpy function. The two methodologies, i.e. the van’t Hoff approach and the isothermal calorimetry, used to determine the enthalpy of micellization of pure surfactants and block copolymers were described. The van’t Hoff method was critically discussed. The aqueous copolymer+surfactant mixtures were analyzed by means of the isothermal titration calorimetry and the enthalpy of transfer of the copolymer from the water to the aqueous surfactant solutions. Thermodynamic models were presented to show the procedure to extract straightforward molecular insights from the bulk properties. PMID:19742173

Method to Predict Tempering of Steels Under Non-isothermal Conditions

Science.gov (United States)

Poirier, D. R.; Kohli, A.

2017-05-01

A common way of representing the tempering responses of steels is with a "tempering parameter" that includes the effect of temperature and time on hardness after hardening. Such functions, usually in graphical form, are available for many steels and have been applied for isothermal tempering. In this article, we demonstrate that the method can be extended to non-isothermal conditions. Controlled heating experiments were done on three grades in order to verify the method.

A hygroscopic method to measure the adsorption isotherm of porous construction materials

NARCIS (Netherlands)

Taher, A.; Zanden, van der A.J.J.; Brouwers, H.J.H.; Stephan, D.; Daake, von H.; Markl, V.; Land, G.

2013-01-01

A sorption isotherm is the relationship between the moisture content in a material and the relative humidity of the surrounding atmosphere in an equilibrium situation. Most often, the sorption isotherm is measured with a gravitational method. This work presents a method to measure the adsorption

Evaluation of theoretical and empirical water vapor sorption isotherm models for soils

DEFF Research Database (Denmark)

Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

2016-01-01

sorption isotherms of building materials, food, and other industrial products, knowledge about the 24 applicability of these functions for soils is noticeably lacking. We present validation of nine models for characterizing adsorption/desorption isotherms for a water activity range from 0.03 to 0...

[Colorimetric detection of HPV6 and HPV16 by loop mediated isothermal amplification].

Science.gov (United States)

Lu, Chun-bin; Luo, Le; Yang, Meng-jie; Nie, Kai; Wang, Miao; Ma, Xue-Jun

2011-01-01

A simple, rapid and sensitive colorimetric loop mediated isothermal amplification (LAMP) method was established to detect HPV6 and HPV 16 respectively. The method employed a set of four specially designed primers that recognized six distinct sequences of HPV6-E6 or HPV16-E7 for amplification of nucleic acid under isothermal conditions at 63 degrees C for one hour. The amplification process of LAMP was monitored by the addition of HNB (hydroxy naphthol blue) dye prior to amplification. A positive reaction was indicated by a color change from violet to sky blue and confirmed by real-time turbidimeter and agarose electrophoresis. Thirteen cervical swab samples having single infection with 13 different HPV genotypes were examined to evaluate the specificity. A serial dilution of a cloned plasmid containing HPV-E6 or HPV-E7 gene was examined to evaluate the sensitivity. The results showed that no cross-reaction with other HPV genotypes was observed. The colorimetric LAMP assay could achieve a sensitivity of 1000 copies, 10-20 times lower than that of real-time PCR. The assay was further evaluated with 62 clinical specimens and consistent results were obtained compared with the detection using Kai Pu HPV Genotyping Kit. We concluded that this colorimetric LAMP assay had potential usefulness for the rapid screening of the HPV6 or HPV16 infection in the laboratories and hospitals of provincial and municipal region in China.

Kinetics of the isothermal decomposition of zirconium hydride: terminal solid solubility for precipitation and dissolution

Science.gov (United States)

Denisov, E. A.; Kompaniets, T. N.; Voyt, A. P.

2018-05-01

The hydrogen permeation technique in the surface-limited regime (SLR) was first used to study the isothermal decomposition of zirconium hydride. It is shown that under isothermal conditions, the hydrogen terminal solid solubility in the α-phase for hydride precipitation (TSSp) and dissolution (TSSd) differ only by 6%, in contrast to the 20-30% indicated in the available literature. It is demonstrated that even the minimum heating/cooling rate (1 C/min) used in the traditional methods of studying TSSp and TSSd is too high to exclude the effect of kinetics on the results obtained.

Isothermal α″ formation in β metastable titanium alloys

International Nuclear Information System (INIS)

Aeby-Gautier, E.; Settefrati, A.; Bruneseaux, F.; Appolaire, B.; Denand, B.; Dehmas, M.; Geandier, G.; Boulet, P.

2013-01-01

Highlights: ► Isothermal kinetics of orthorhombic α″ formation is characterized by HEXRD. ► Cell parameters of parent and product phases are obtained. ► Partitioning of solutes during the transformation and the ageing is discussed. -- Abstract: Thanks to time resolved high energy X-ray diffraction, isothermal decomposition of β metastable phase was studied, directly after solution treatment in the β temperature range, for temperatures ranging from 300 to 450 °C for two beta metastable alloys (Ti 17 and Ti 5553). The formation of an orthorhombic α″ phase is clearly identified at the beginning of the transformation whatever the alloy studied. If transformation occurs at the higher temperature an evolution of α″ is observed toward the hexagonal α phase. The phase amounts and the mean cell parameters of each phase were quantified by the Rietveld refinement method. The obtained cell parameters evolutions and the orthorhombicity of α″ are discussed. Moreover, the orthorhombicity of α″ compared to that obtained for stress induced martensite may indicate a slight partitioning of solutes in isothermal α″

Isothermal α″ formation in β metastable titanium alloys

Energy Technology Data Exchange (ETDEWEB)

Aeby-Gautier, E., E-mail: Elisabeth.Gautier@mines.inpl-nancy.fr [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Settefrati, A. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Airbus Operations, Materials and Processes, Toulouse (France); Bruneseaux, F. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Appolaire, B. [Laboratoire d’Etudes des Microstructures ONERA – CNRS Chatillon (France); Denand, B.; Dehmas, M.; Geandier, G.; Boulet, P. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France)

2013-11-15

Highlights: ► Isothermal kinetics of orthorhombic α″ formation is characterized by HEXRD. ► Cell parameters of parent and product phases are obtained. ► Partitioning of solutes during the transformation and the ageing is discussed. -- Abstract: Thanks to time resolved high energy X-ray diffraction, isothermal decomposition of β metastable phase was studied, directly after solution treatment in the β temperature range, for temperatures ranging from 300 to 450 °C for two beta metastable alloys (Ti 17 and Ti 5553). The formation of an orthorhombic α″ phase is clearly identified at the beginning of the transformation whatever the alloy studied. If transformation occurs at the higher temperature an evolution of α″ is observed toward the hexagonal α phase. The phase amounts and the mean cell parameters of each phase were quantified by the Rietveld refinement method. The obtained cell parameters evolutions and the orthorhombicity of α″ are discussed. Moreover, the orthorhombicity of α″ compared to that obtained for stress induced martensite may indicate a slight partitioning of solutes in isothermal α″.

Adsorption Isotherms of CH 4 on Activated Carbon from Indonesian Low Grade Coal

KAUST Repository

Martin, Awaludin; Loh, Wai Soong; Rahman, Kazi Afzalur; Thu, Kyaw; Surayawan, Bambang; Alhamid, M. Idrus; Nasruddin,; Ng, Kim Choon

2011-01-01

) apparatus, and two types of activated carbon have been investigated, namely, activated carbon derived from the low rank coal of the East of Kalimantan, Indonesia, and a Carbotech activated carbon. The isotherm results which cover temperatures from (300

Calibrated expressions for welding and their application to isotherm width in a thick plate

Directory of Open Access Journals (Sweden)

Gentry Wood

2014-09-01

Full Text Available The present paper introduces a possible solution to the limitations of modern trial and error solutions to welding procedure development. The difficulties of finding generalized solutions to Rosenthal´s equation are discussed and the Minimal Representation and Calibration approach is introduced as a promising procedure for developing these solutions. Dominant factors are identified, with effects from secondary phenomena being taken into account by correction factors. These correction factors are then calibrated and presented in a form that can be easily computed, and therefore be amendable to industry. The approach is then demonstrated by determining the isotherm width from Rosenthal´s thick plate solution. Comparison of the calibrated scaling equations to Rosenthal´s exact solution showed a maximum error of less than 0.8% for any isotherm.

Isothermal pumping analysis for high-altitude tethered balloons.

Science.gov (United States)

Kuo, Kirsty A; Hunt, Hugh E M

2015-06-01

High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe.

Determination of field-based sorption isotherms for Cd, Cu, Pb and Zn in Dutch soils

NARCIS (Netherlands)

Otte JG; Grinsven JJM van; Peijnenburg WJGM; Tiktak A; LBG; ECO

1999-01-01

Sorption isotherms for metals in soil obtained in the laboratory generally underpredict the observed metal content in the solid phase in the field. Isotherms based on in-situ data are therefore required. The aim of this study is to obtain field-based sorption isotherms for Cd, Cu, Pb and Zn as input

Equilibrium isotherms, kinetics, and thermodynamics studies for congo red adsorption using calcium alginate beads impregnated with nano-goethite.

Science.gov (United States)

Munagapati, Venkata Subbaiah; Kim, Dong-Su

2017-07-01

The present study is concerned with the batch adsorption of congo red (CR) from an aqueous solution using calcium alginate beads impregnated with nano-goethite (CABI nano-goethite) as an adsorbent. The optimum conditions for CR removal were determined by studying operational variables viz. pH, adsorbent dose, contact time, initial dye ion concentration and temperature. The CABI nano-goethite was characterized by Fourier transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis. The CR sorption data onto CABI nano-goethite were described using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The results show that the best fit was achieved with the Langmuir isotherm model. The maximum adsorption capacity (181.1mg/g) of CR was occurred at pH 3.0. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Desorption experiments were carried out to explore the feasibility of regenerating the adsorbent and the adsorbed CR from CABI nano-goethite. The best desorbing agent was 0.1M NaOH with an efficiency of 94% recovery. The thermodynamic parameters ΔG°, ΔH°, and ΔS° for the CR adsorption were determined by using adsorption capacities at five different temperatures (293, 303, 313, 323 and 303K). Results show that the adsorption process was endothermic and favoured at high temperature. Copyright © 2017 Elsevier Inc. All rights reserved.

Adsorption of surfactants on sand surface in enhanced oil recovery: Isotherms, kinetics and thermodynamic studies

Energy Technology Data Exchange (ETDEWEB)

Bera, Achinta; Kumar, T.; Ojha, Keka; Mandal, Ajay, E-mail: mandal_ajay@hotmail.com

2013-11-01

Adsorption of surfactants onto reservoir rock surface may result in the loss and reduction of their concentrations in surfactant flooding, which may render them less efficient or ineffective in practical applications of enhanced oil recovery (EOR) techniques. Surfactant flooding for EOR received attraction due to its ability to increase the displacement efficiency by lowering the interfacial tension between oil and water and mobilizing the residual oil. This article highlights the adsorption of surfactants onto sand surface with variation of different influencing factors. It has been experimentally found that adsorption of cationic surfactant on sand surface is more and less for anionic surfactant, while non-ionic surfactant shows intermediate behaviour. X-ray diffraction (XRD) study of clean sand particles has been made to determine the main component present in the sand particles. The interaction between sand particles and surfactant has been studied by Fourier Transform Infrared (FTIR) Spectroscopy of the sand particles before and after aging with surfactant. Salinity plays an important role in adsorption of anionic surfactant. Batch experiments were also performed to understand the effects of pH and adsorbent dose on the sorption efficiency. The sand particles exhibited high adsorption efficiency at low pH for anionic and nonionic surfactants. But opposite trend was found for cationic surfactant. Adsorption data were analyzed by fitting with Langmuir, Freundlich, Redlich-Peterson, and Sips isotherm models. Results show that the Langmuir isotherm and pseudo-second order kinetics models suit the equilibrium and kinetics of adsorption on sand surface. Thermodynamics feasibility of the adsorption process was also studied to verify the spontaneity of the process.

Integrated nozzle - flapper valve with piezoelectric actuator and isothermal chamber: a feedback linearization multi control device

Energy Technology Data Exchange (ETDEWEB)

Kamali, Mohammadreza; Jazayeri, Seyed Ali [K. N.Toosi University of Technology, Tehran (Iran, Islamic Republic of); Najafi, Farid [University of Guilan, Rasht (Iran, Islamic Republic of); Kawashima, Kenji [Tokyo Medical and Dental University, Tokyo (Japan); Kagawa, Toshiharu [Tokyo Institute of Technology, Tokyo (Japan)

2016-05-15

This paper introduces a new nozzle-flapper valve with isothermal chamber using piezoelectric actuator. It controls the pressure and flow rate simply, effectively and separately. The proposed valve uses isothermal chamber presenting practical isothermal condition due to its large heat transfer interfaces filled by metal wool. The valve uses stacked type piezoelectric actuator with unique advantages. By using this valve, a simple method has been fulfilled to control flow rate or pressure of ideal gases in a pneumatic actuators. Experimental results demonstrated applications of the proposed valve to control either pressure or flow rate in pneumatic circuits. This valve can be also used in the pilot stage valve to actuate the main stage of a much bigger pneumatic valve. Designated structure contains only one pressure sensor installed on the isothermal control chamber, capable of controlling both pressure and flow rate. The desired output mass flow rate of the valve is controlled by the pressure changes during positioning of piezoelectric actuator at proper position. The proposed valve can control steady and unsteady oscillatory flow rate and pressure effectively, using nonlinear control method such as feedback linearization approach. Its effectiveness is demonstrated and validated through simulation and experiments.

Non-isothermal irradiation creep of nickel alloys Inconel 706 and PE-16

International Nuclear Information System (INIS)

Gilbert, E.R.; Chin, B.A.

1984-06-01

The results of in-reactor step temperature change experiments conducted on two nickel alloys, PE-16 and Inconel 706, were evaluated to determine the creep behavior under nonisothermal conditions. The effect of the temperature changes was found to be significantly different for the two alloys. Following a step temperature change, the creep rate of PE-16 adjusted to the rate found in isothermal tests at the new temperature. In contrast for Inconel 706, a reduction in temperature from 540 to 425 0 C produced a 300% increase in creep above that measured at 540 0 C in isothermal tests. The response of in-reactor creep in Inconel 706 to temperature changes was attributed to the dissolution of the gamma double-prime phase and subsequent loss of precipitation-strengthening at temperatures below 500 C

Precipitation and mechanical properties of Nb-modified ferritic stainless steel during isothermal aging

International Nuclear Information System (INIS)

Yan Haitao; Bi Hongyun; Li Xin; Xu Zhou

2009-01-01

The influence of isothermal aging on precipitation behavior and mechanical properties of Nb-modified ferritic stainless steel was investigated using Thermo-calc software, scanning electron microscopy and transmission electron microscopy. It was observed that TiN, NbC and Fe 2 Nb formed in the investigated steel and the experimental results agreed well with the results calculated by Thermo-calc software. During isothermal aging at 800 deg. C, the coarsening rate of Fe 2 Nb is greater than that of NbC, and the calculated average sizes of NbC and Fe 2 Nb of the aged specimen agreed with the experimental results. In addition, the tensile strength and micro-hardness of the ferritic stainless steel increased with increased aging time from 24 h to 48 h. But aging at 800 deg. C for 96 h caused the coarsening of the precipitation, which led to a decrease of tensile strength and micro-hardness

Thermodynamic investigations of protein's behaviour with ionic liquids in aqueous medium studied by isothermal titration calorimetry.

Science.gov (United States)

Bharmoria, Pankaj; Kumar, Arvind

2016-05-01

While a number of reports appear on ionic liquids-proteins interactions, their thermodynamic behaviour using suitable technique like isothermal titration calorimetry is not systematically presented. Isothermal titration calorimetry (ITC) is a key technique which can directly measure the thermodynamic contribution of IL binding to protein, particularly the enthalpy, heat capacities and binding stoichiometry. Ionic liquids (ILs), owing to their unique and tunable physicochemical properties have been the central area of scientific research besides graphene in the last decade, and growing unabated. Their encounter with proteins in the biological system is inevitable considering their environmental discharge though most of them are recyclable for a number of cycles. In this article we will cover the thermodynamics of proteins upon interaction with ILs as osmolyte and surfactant. The up to date literature survey of IL-protein interactions using isothermal titration calorimetry will be discussed and parallel comparison with the results obtained for such studies with other techniques will be highlighted to demonstrate the accuracy of ITC technique. Net stability of proteins can be obtained from the difference in the free energy (ΔG) of the native (folded) and denatured (unfolded) state using the Gibbs-Helmholtz equation (ΔG=ΔH-TΔS). Isothermal titration calorimetry can directly measure the heat changes upon IL-protein interactions. Calculation of other thermodynamic parameters such as entropy, binding constant and free energy depends upon the proper fitting of the binding isotherms using various fitting models. Copyright © 2015 Elsevier B.V. All rights reserved.

Innovative isothermal oil-free co-rotating scroll compressor–expander for energy storage with first expander tests

International Nuclear Information System (INIS)

Iglesias, A.; Favrat, D.

2014-01-01

Highlights: • Doing a new concept of small scale compressed air energy storage. • Presenting a new working process of scroll machinery. • Updating a thermodynamic model of scroll compressor that take into account water injection. • Updating a mathematical model of volumetric loses that take into account sealing effect of liquid water. • Encouraging results to investigate more deeply this new concept. - Abstract: The development of an efficient isothermal turbine and compressor is essential for the realization of a small-scale compressed air energy storage (CAES). This article presents the theoretical development of an oil-free co-rotating scroll air compressor and turbine working with water injection to make the operations of expansion and compression as isothermal as possible. First experimental results in expander mode are shown. The theoretical performance is predicted with the help of a mathematical model using the equations of energy and mass conservation and the equation of state. This model takes into account the effects of water injection and volumetric losses. The experimental prototype is an oil-free scroll air compressor with the distinctive feature of having two mobile involutes working in synchronized co-rotation one relative to another. The prime-mover is an electric motor driving the two scrolls with two synchronizing belts. Water injection in the housing intends to provide a quasi-isothermal compression. The same device is used as an isothermal expander by supplying high-pressure air with water when it rotates backwards in expander mode, the electric motor acting then as a generator. Expected improvements to a standard scroll compressor and expander are a better volumetric efficiency and a greater power density due to a higher rotational speed of the scrolls, thanks to their symmetrical masses. The isothermal processes increase also the overall performance

Typical parameters of the plasma chemical similarity in non-isothermal reactive plasmas

International Nuclear Information System (INIS)

Gundermann, S.; Jacobs, H.; Miethke, F.; Rutsher, A.; Wagner, H.E.

1996-01-01

The substance of physical similarity principles is contained in parameters which govern the comparison of different realizations of a model device. Because similarity parameters for non-isothermal plasma chemical reactors are unknown to a great extent, an analysis of relevant equations is given together with some experimental results. Modelling of the reactor and experimental results for the ozone synthesis are presented

Summary report on the evaluation of a 1977--1985 edited sorption data base for isotherm modeling

International Nuclear Information System (INIS)

Polzer, W.L.; Beckman, R.J.; Fuentes, H.R.; Yong, C.; Chan, P.; Rao, M.G.

1993-01-01

Sorption data bases collected by Los Alamos National Laboratory (LANL) from 1977 to 1985 for the Yucca Mountain Project.(YMP) have been inventoried and fitted with isotherm expressions. Effects of variables (e.g., particle size) on the isotherm were also evaluated. The sorption data are from laboratory batch measurements which were not designed specifically for isotherm modeling. However a limited number of data sets permitted such modeling. The analysis of those isotherm data can aid in the design of future sorption experiments and can provide expressions to be used in radionuclide transport modeling. Over 1200 experimental observations were inventoried for their adequacy to be modeled b isotherms and to evaluate the effects of variables on isotherms. About 15% of the observations provided suitable data sets for modeling. The data sets were obtained under conditions that include ambient temperature and two atmospheres, air and CO 2

Exponential isothermal amplification of nucleic acids and amplified assays for proteins, cells, and enzyme activities.

Science.gov (United States)

Reid, Michael S; Le, X Chris; Zhang, Hongquan

2018-04-27

Isothermal exponential amplification techniques, such as strand-displacement amplification (SDA), rolling circle amplification (RCA), loop-mediated isothermal amplification (LAMP), nucleic acid sequence-based amplification (NASBA), helicase-dependent amplification (HDA), and recombinase polymerase amplification (RPA), have great potential for on-site, point-of-care, and in-situ assay applications. These amplification techniques eliminate the need for temperature cycling required for polymerase chain reaction (PCR) while achieving comparable amplification yield. We highlight here recent advances in exponential amplification reaction (EXPAR) for the detection of nucleic acids, proteins, enzyme activities, cells, and metal ions. We discuss design strategies, enzyme reactions, detection techniques, and key features. Incorporation of fluorescence, colorimetric, chemiluminescence, Raman, and electrochemical approaches enables highly sensitive detection of a variety of targets. Remaining issues, such as undesirable background amplification resulting from non-specific template interactions, must be addressed to further improve isothermal and exponential amplification techniques. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

β → α isothermal transformation in pure and weakly alloyed uranium

International Nuclear Information System (INIS)

Aubert, H.; Lelong, C.

1966-01-01

The TTT diagrams describing the β → α isothermal transformation have been made by isothermal dilatometry for pure uranium and 21 alloys based on chromium, silicon, molybdenum, iron, aluminium, zirconium. The thermal cycle preceding the isothermal step influences the decomposition kinetics at temperature corresponding to the eutectoid and martensitic mechanisms, but not in the range where the bainitic transformation occurs. The stability of the β phase decreases with the chromium, molybdenum and silicon concentration: it is affected differently for each of the three transformation mechanisms. The ternary additions, even at very low concentration have a considerable effect on the stability. When the concentration decreases the martensitic mechanism is active at progressively higher temperature, diminishing to the point of disappearance the temperature range where the transformation is considered as being of the bainitic mode. (author) [fr

Isothermal temperature reactivity coefficient measurement in TRIGA reactor

International Nuclear Information System (INIS)

Zagar, T.; Ravnik, M.; Trkov, A.

2002-01-01

Direct measurement of an isothermal temperature reactivity coefficient at room temperatures in TRIGA Mark II research reactor at Jozef Stefan Institute in Ljubljana is presented. Temperature reactivity coefficient was measured in the temperature range between 15 o C and 25 o C. All reactivity measurements were performed at almost zero reactor power to reduce or completely eliminate nuclear heating. Slow and steady temperature decrease was controlled using the reactor tank cooling system. In this way the temperatures of fuel, of moderator and of coolant were kept in equilibrium throughout the measurements. It was found out that TRIGA reactor core loaded with standard fuel elements with stainless steel cladding has small positive isothermal temperature reactivity coefficient in this temperature range.(author)

THERMODYNAMICS AND ADSORPTION ISOTHERMS FOR THE ...

African Journals Online (AJOL)

BAFFA

The use of maize (Zea mays) cob for the biosorption of Cr(VI), Ni(II) and Cd(II) is ... Variations in the concentration of the different adsorbates during the adsorption process .... Langmuir isotherm is the dimensionless separation .... The use of Sago waste for the sorption of lead and copper. Water S. Afr., 24 (3), p251-256.

Extraction liquide-liquide des sels minéraux. Approximation analytique des isothermes de partage. Application au calcul sur ordinateur d'une installation Liquid-Liquid Extraction of Mineral Salts. Analytical Approximation of Partition Isotherms. Application to the Computer Designing of an Installation

Directory of Open Access Journals (Sweden)

Chaid M. T.

2006-11-01

Full Text Available Cet article comporte deux parties -dans la première on a calculé les isothermes de partage en partant des considérations thermodynamiques basées sur les travaux de Guggenheim. Les résultats ne sont bons que dans le cas des solutions idéales. On a donc simulé les isothermes par des fonctions analytiques. Celles-ci permettent de représenter convenablement tous les faisceaux d'isothermes quelles que soient l'acidité de la solution aqueuse et les concentrations dans les deux phases; - la deuxième partie est réservée au calcul d'une installation complète d'extraction avec colonne de récupération; le calcul, mené sur ordinateur, utilise les fonctions analytiques précédentes et permet d'obtenir les débits et les concentrations à chaque plateau. This article contains two parts: - the first part discusses the calculating of partition isotherms using thermodynamic considerations based on research by Guggenheim. The results are good only in the case of ideal solutions. Therefore, isotherms were simulated by ànalyticfunctionswhich are suitable for representing all isotherm bundles no matter what the acidity of the aqueous solution and the concentrations in both phases moy be. - the second part 'deals' with designing a complete extraction installation with a recovery column. Computerized designing makes use of the preceding analytic functions and enables flowrates and concentrations ta be determined at each plate.

Simultaneous removal of potent cyanotoxins from water using magnetophoretic nanoparticle of polypyrrole: adsorption kinetic and isotherm study.

Science.gov (United States)

Hena, S; Rozi, R; Tabassum, S; Huda, A

2016-08-01

Cyanotoxins, microcystins and cylindrospermopsin, are potent toxins produced by cyanobacteria in potable water supplies. This study investigated the removal of cyanotoxins from aqueous media by magnetophoretic nanoparticle of polypyrrole adsorbent. The adsorption process was pH dependent with maximum adsorption occurring at pH 7 for microcystin-LA, LR, and YR and at pH 9 for microcystin-RR and cylindrospermopsin (CYN). Kinetic studies and adsorption isotherms reflected better fit for pseudo-second-order rate and Langmuir isotherm model, respectively. Thermodynamic calculations showed that the cyanotoxin adsorption process is endothermic and spontaneous in nature. The regenerated adsorbent can be successfully reused without appreciable loss of its original capacity.

Effect of Morphological Differences on the Cold Formability of an Isothermally Heat-Treated Advanced High-Strength Steel

Science.gov (United States)

Weißensteiner, Irmgard; Suppan, Clemens; Hebesberger, Thomas; Winkelhofer, Florian; Clemens, Helmut; Maier-Kiener, Verena

2018-04-01

Steel sheets of Fe-0.2C-2Mn-0.2Si-0.03Ti-0.003B (m%) for the automotive industry were isothermally heat-treated, comprising austenitizing and subsequent isothermal annealing at temperatures between 300°C and 500°C. As a consequence, microstructures ranging from granular bainite over lower bainite to auto-tempered and untempered martensite were obtained. In tensile, hole expansion and bending tests, the performances in different forming conditions were compared and the changes of microstructure and texture were studied by complementary electron backscatter diffraction (EBSD) analyses. Samples with granular bainitic microstructures exhibited high total elongations but lower hole expansion ratios; in subsequent EBSD and texture analyses, evidence for inhomogeneous deformation was found. In contrast, the lath-like bainitic/martensitic microstructure showed higher strength and lower elongation to fracture. This results in a reduced bendability, but also in a high tolerance against damage induced by the shearing of edges, and, thus, allows homogeneous deformation to higher strains in the hole expansion test.

Large eddy simulations of isothermal confined swirling flow in an industrial gas-turbine

International Nuclear Information System (INIS)

Bulat, G.; Jones, W.P.; Navarro-Martinez, S.

2015-01-01

Highlights: • We conduct a large eddy simulation of an industrial gas turbine. • The results are compared with measurements obtained under isothermal conditions. • The method reproduces the observed precessing vortex and central vortex cores. • The profiles of mean and rms velocities are found to be captured to a good accuracy. - Abstract: The paper describes the results of a computational study of the strongly swirling isothermal flow in the combustion chamber of an industrial gas turbine. The flow field characteristics are computed using large eddy simulation in conjunction with a dynamic version of the Smagorinsky model for the sub-grid-scale stresses. Grid refinement studies demonstrate that the results are essentially grid independent. The LES results are compared with an extensive set of measurements and the agreement with these is overall good. The method is shown to be capable of reproducing the observed precessing vortex and central vortex cores and the profiles of mean and rms velocities are found to be captured to a good accuracy. The overall flow structure is shown to be virtually independent of Reynolds number

RAND-Based Formulations for Isothermal Multiphase Flash

DEFF Research Database (Denmark)

Paterson, Duncan; Michelsen, Michael L.; Stenby, Erling H.

2018-01-01

Two algorithms are proposed for isothermal multiphase flash. These are referred to as modified RAND and vol-RAND. The former uses the chemical potentials and molar-phase amounts as the iteration variables, while the latter uses chemical potentials and phase volumes to cosolve a pressure...

Water Adsorption Isotherms on Fly Ash from Several Sources.

Science.gov (United States)

Navea, Juan G; Richmond, Emily; Stortini, Talia; Greenspan, Jillian

2017-10-03

In this study, horizontal attenuated total reflection (HATR) Fourier-transform infrared (FT-IR) spectroscopy was combined with quartz crystal microbalance (QCM) gravimetry to investigate the adsorption isotherms of water on fly ash, a byproduct of coal combustion in power plants. Because of composition variability with the source region, water uptake was studied at room temperature as a function of relative humidity (RH) on fly ash from several regions: United States, India, The Netherlands, and Germany. The FT-IR spectra show water features growth as a function of RH, with water absorbing on the particle surface in both an ordered (ice-like) and a disordered (liquid-like) structure. The QCM data was modeled using the Brunauer, Emmett, and Teller (BET) adsorption isotherm model. The BET model was found to describe the data well over the entire range of RH, showing that water uptake on fly ash takes place mostly on the surface of the particle, even for poorly combusted samples. In addition, the source region and power-plant efficiency play important roles in the water uptake and ice nucleation (IN) ability of fly ash. The difference in the observed water uptake and IN behavior between the four samples and mullite (3Al 2 O 3 ·2SiO 2 ), the aluminosilicate main component of fly ash, is attributed to differences in composition and the density of OH binding sites on the surface of each sample. A discussion is presented on the RH required to reach monolayer coverage on each sample as well as a comparison between surface sites of fly ash samples and enthalpies of adsorption of water between the samples and mullite.

A Universal Isotherm Model to Capture Adsorption Uptake and Energy Distribution of Porous Heterogeneous Surface

KAUST Repository

Ng, Kim Choon; Burhan, Muhammad; Shahzad, Muhammad Wakil; Ismail, Azahar Bin

2017-01-01

The adsorbate-adsorbent thermodynamics are complex as it is influenced by the pore size distributions, surface heterogeneity and site energy distribution, as well as the adsorbate properties. Together, these parameters defined the adsorbate uptake forming the state diagrams, known as the adsorption isotherms, when the sorption site energy on the pore surfaces are favorable. The available adsorption models for describing the vapor uptake or isotherms, hitherto, are individually defined to correlate to a certain type of isotherm patterns. There is yet a universal approach in developing these isotherm models. In this paper, we demonstrate that the characteristics of all sorption isotherm types can be succinctly unified by a revised Langmuir model when merged with the concepts of Homotattic Patch Approximation (HPA) and the availability of multiple sets of site energy accompanied by their respective fractional probability factors. The total uptake (q/q*) at assorted pressure ratios (P/P s ) are inextricably traced to the manner the site energies are spread, either naturally or engineered by scientists, over and across the heterogeneous surfaces. An insight to the porous heterogeneous surface characteristics, in terms of adsorption site availability has been presented, describing the unique behavior of each isotherm type.

A Universal Isotherm Model to Capture Adsorption Uptake and Energy Distribution of Porous Heterogeneous Surface

KAUST Repository

Ng, Kim Choon

2017-08-31

The adsorbate-adsorbent thermodynamics are complex as it is influenced by the pore size distributions, surface heterogeneity and site energy distribution, as well as the adsorbate properties. Together, these parameters defined the adsorbate uptake forming the state diagrams, known as the adsorption isotherms, when the sorption site energy on the pore surfaces are favorable. The available adsorption models for describing the vapor uptake or isotherms, hitherto, are individually defined to correlate to a certain type of isotherm patterns. There is yet a universal approach in developing these isotherm models. In this paper, we demonstrate that the characteristics of all sorption isotherm types can be succinctly unified by a revised Langmuir model when merged with the concepts of Homotattic Patch Approximation (HPA) and the availability of multiple sets of site energy accompanied by their respective fractional probability factors. The total uptake (q/q*) at assorted pressure ratios (P/P s ) are inextricably traced to the manner the site energies are spread, either naturally or engineered by scientists, over and across the heterogeneous surfaces. An insight to the porous heterogeneous surface characteristics, in terms of adsorption site availability has been presented, describing the unique behavior of each isotherm type.

Rapid identification and differentiation of Fasciola hepatica and Fasciola gigantica by a loop-mediated isothermal amplification (LAMP) assay.

Science.gov (United States)

Ai, L; Li, C; Elsheikha, H M; Hong, S J; Chen, J X; Chen, S H; Li, X; Cai, X Q; Chen, M X; Zhu, X Q

2010-12-15

The present study developed and validated a species-specific loop-mediated isothermal amplification (LAMP) assay for the rapid detection and discrimination of Fasciola hepatica and Fasciola gigantica. The LAMP assay is inexpensive, easy to perform and shows rapid reaction, wherein the amplification can be obtained in 45 min under isothermal conditions of 61 °C or 62 °C by employing a set of four species-specific primer mixtures and results can be checked through naked-eye visualization. The optimal assay conditions with no cross-reaction with other closely related trematodes (Clonorchis sinensis, Opisthorchis viverrini, Orientobilharzia turkestanicum and Schistosoma japonicum) as well as within the two Fasciola species were established. The assay was validated by examining F. gigantica DNA in the intermediate host snails and in faecal samples. The results indicated that the LAMP assay is approximately 10(4) times more sensitive than the conventional specific PCR assays. These findings indicate that this Fasciola species-specific LAMP assay may have a potential clinical application for detection and differentiation of Fasciola species, especially in endemic countries. Copyright © 2010 Elsevier B.V. All rights reserved.

TRANSFORMATION ISOTHERME D'UN ACIER A HAUTE RESISTANCE 40 CDV 13

Directory of Open Access Journals (Sweden)

A BOUTEFNOUCHET

2001-06-01

Full Text Available L'étude dilatométrique du comportement de l'austénite en condition isotherme d'un acier ternaire, à haute résistance mécanique de nuance 40 CDV 13, nous a permis de tracer son diagramme TTT. L'austénitisation a été réalisée pendant 10 minutes à  qg = 950°C (utilisée dans  l'industrie. Les températures de maintien sont comprises entre Ac1 = 810°C et Ms  = 310°C. Dans ce diagramme TTT, on distingue deux domaines de transformation isotherme de l'austénite. Le domaine I (625°C £  qiso < Ac1 = 810°C dans lequel l'austénite se transforme en ferrite et en perlite, et le domaine II (325°C  £  qiso £ 475°C où l'austénite se transforme en bainite ou en ferrite probainitique. Ces transformations sont précédées pour toutes les températures de maintien isotherme d'une précipitation de carbures. En outre, ces deux domaines de transformation de l'austénite sont séparés par une large zone de stabilité de l'austénite comprise entre 500°C et 600°C. L'analyse approfondie des courbes dilatométriques enregistrées durant le maintien isotherme et le refroidissement final jusqu'à l'ambiante, nous a permis de déterminer qualitativement et quantitativement les phase mises en jeu par ces transformations isothermes de l'austénite.

Adsorptive removal of malachite green from aqueous solutions by almond gum: Kinetic study and equilibrium isotherms.

Science.gov (United States)

Bouaziz, Fatma; Koubaa, Mohamed; Kallel, Fatma; Ghorbel, Rhoudha Ellouz; Chaabouni, Semia Ellouz

2017-12-01

This work aimed at investigating the potential of almond gum as low cost adsorbent for the removal of the cationic dye; malachite green from aqueous solutions. Almond gum was first analyzed by scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR), and then the adsorption behavior was studied in batch system. The effects of the adsorption parameters (adsorbent dose, pH, contact time, particle size, initial dye concentration, temperature and agitation) on the dye removal have been studied. Adsorption equilibrium and isotherms were evaluated depending on temperature using the isotherms of Freundlich, Langmuir, and Tempkin. The obtained result showed that both Langmuir and Freundlich models were adapted to study the dye sorption. The maximum adsorption capacities were equal to 172.41mg/g, 181.81mg/g, and 196.07mg/g at 303.16K, 313.16K, and 323.16K, respectively. The kinetics of sorption were following the pseudo-second order model. The thermodynamic changes in enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) indicated that the adsorption of malachite green at the surface of almond gum is endothermic and occurs spontaneously. Desorption experiments were conducted to regenerate almond gum, showing great desorption capacity when using HCl at pH 2. Copyright © 2017 Elsevier B.V. All rights reserved.

Grain refinement of AZ91D alloy by intensive melt shearing and its persistence after remelting and isothermal holding

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Zuo Yubo

2013-01-01

Full Text Available Intensive melt shearing has a significant grain refining effect on some light alloys. However, the persistence of the grain refining effect during isothermal holding and remelting is still unclear, although it is very important for the practical application. In this study, intensive melt shearing was achieved in a twin-screw mechanism to investigate its grain refining effect on AZ91D magnesium alloy. The refinement mechanism was discussed and the persistence of grain refinement after remelting and isothermal holding was also studied. A Zeiss imaging system with polarized light was used for quantitative measurement of grain size. The results show that the intensive melt shearing has a significant grain refining effect on AZ91D magnesium alloy. With the application of intensive melt shearing, the grain size of AZ91D magnesium alloy can be reduced from 530 μm (for a typical as-cast microstructure to 170 μm, which is about 70% size reduction. The grain refinement achieved by the intensive melt shearing can be partially kept after isothermal holding and remelting. It is believed that the refinement effect was mainly due to the finer and well dispersed oxide particles formed by high intensive shearing. The smaller size of oxide particles and their slow motion velocity in the sheared melt could make important contributions to the remained grain refinement.

Isothermal Titration Calorimetry and Fluorescence Spectroscopy Study Of Asphaltene Self-Association In Toluene And Interaction With A Model Resin

DEFF Research Database (Denmark)

Garcia, Daniel Merino; Andersen, Simon Ivar

2002-01-01

This article collects the work performed by Isothermal Titration Caloritnetry (ITC) in the study of the self-association of asphaltenes in toluene solutions. Calorimetric experiments show that asphaltenes, start self-associating at very low concentrations and that the existence of a Critical...... with the results of the titration of three model molecules: nonylphenol, which associates by means of hydrogen bond formation, and coronene and pyrene, which associates by stacking. The results obtained leave open the question about the model-stacking molecules, as it was not possible to elucidate whether they do...

Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

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E. E. Louvaris

2017-10-01

Full Text Available A method is developed following the work of Grieshop et al. (2009 for the determination of the organic aerosol (OA volatility distribution combining thermodenuder (TD and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a scanning mobility particle sizer (SMPS. In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60–75 % of the cooking OA (COA at concentrations around 500 µg m−3 consisted of low-volatility organic compounds (LVOCs, 20–30 % of semivolatile organic compounds (SVOCs, and around 10 % of intermediate-volatility organic compounds (IVOCs. The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol−1 and the effective accommodation coefficient was 0.06–0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

Science.gov (United States)

Louvaris, Evangelos E.; Karnezi, Eleni; Kostenidou, Evangelia; Kaltsonoudis, Christos; Pandis, Spyros N.

2017-10-01

A method is developed following the work of Grieshop et al. (2009) for the determination of the organic aerosol (OA) volatility distribution combining thermodenuder (TD) and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA) produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a scanning mobility particle sizer (SMPS). In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60-75 % of the cooking OA (COA) at concentrations around 500 µg m-3 consisted of low-volatility organic compounds (LVOCs), 20-30 % of semivolatile organic compounds (SVOCs), and around 10 % of intermediate-volatility organic compounds (IVOCs). The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol-1 and the effective accommodation coefficient was 0.06-0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

Quasi-equilibria and plasma chemical similarity in non-isothermal reactive plasmas

International Nuclear Information System (INIS)

Miethke, F.; Rutscher, A.; Wagner, H.E.

2000-01-01

With regard to the output of stable products the mode of operation of non-isothermal plasma chemical reactors shows physical and chemical well defined states, which represent limiting cases and may be interpreted as quasi-equilibrium states. The occurrence and the characteristics of these states, meanwhile more than once observed and described, are demonstrated by an instructive model reaction. Within the frame of the so-called Macroscopic Kinetics a central parameter is dominating the reactor operation. This result may be generalized and is linked up to the application of similarity principles for the reactor operation. After the general formulation of such principles, starting from the balance equations of particles and energy, a dimensionless similarity parameter is formulated, characterizing the composition of the effluent gas of the reactor. The applicability of this parameter is demonstrated by experimental examples. (Authors)

Non-isothermal effects on SO2 absorption by water droplets. I - Model development. II - Results and discussion

Science.gov (United States)

Reda, M.; Carmichael, G. R.

1982-01-01

An analytic model of SO2 absorption in a falling water droplet is developed and a simulation of SO2 washout is performed. Nonisothermic effects on drop growth, droplet physical parameters, reaction rates, and multicomponent diffusion are treated in the model. The gas-liquid interface is assumed to be at equilibrium, and interfacial resistance is negligible. Raindrops are simulated as falling from a 2 km height through an atmospheric region containing SO2. The droplets decrease in size from evaporation and cooling, and their slightly basic pH aids SO2 absorption. The simulation indicates higher SO2 absorption at higher altitudes, and desorption may occur at ground level. Isothermal effects are concluded to be significant, and quantification of effects will depend on further modelling.

Ammonium removal from aqueous solutions by clinoptilolite: determination of isotherm and thermodynamic parameters and comparison of kinetics by the double exponential model and conventional kinetic models.

Science.gov (United States)

Tosun, Ismail

2012-03-01

The adsorption isotherm, the adsorption kinetics, and the thermodynamic parameters of ammonium removal from aqueous solution by using clinoptilolite in aqueous solution was investigated in this study. Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R)) and four three-parameter (Redlich-Peterson (R-P), Sips, Toth and Khan) isotherm models. D-R and R-P isotherms were the models that best fitted to experimental data over the other two- and three-parameter models applied. The adsorption energy (E) from the D-R isotherm was found to be approximately 7 kJ/mol for the ammonium-clinoptilolite system, thereby indicating that ammonium is adsorbed on clinoptilolite by physisorption. Kinetic parameters were determined by analyzing the nth-order kinetic model, the modified second-order model and the double exponential model, and each model resulted in a coefficient of determination (R(2)) of above 0.989 with an average relative error lower than 5%. A Double Exponential Model (DEM) showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) of ammonium-clinoptilolite system were estimated by using the thermodynamic equilibrium coefficients.

Ammonium Removal from Aqueous Solutions by Clinoptilolite: Determination of Isotherm and Thermodynamic Parameters and Comparison of Kinetics by the Double Exponential Model and Conventional Kinetic Models

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İsmail Tosun

2012-03-01

Full Text Available The adsorption isotherm, the adsorption kinetics, and the thermodynamic parameters of ammonium removal from aqueous solution by using clinoptilolite in aqueous solution was investigated in this study. Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R and four three-parameter (Redlich-Peterson (R-P, Sips, Toth and Khan isotherm models. D-R and R-P isotherms were the models that best fitted to experimental data over the other two- and three-parameter models applied. The adsorption energy (E from the D-R isotherm was found to be approximately 7 kJ/mol for the ammonium-clinoptilolite system, thereby indicating that ammonium is adsorbed on clinoptilolite by physisorption. Kinetic parameters were determined by analyzing the nth-order kinetic model, the modified second-order model and the double exponential model, and each model resulted in a coefficient of determination (R2 of above 0.989 with an average relative error lower than 5%. A Double Exponential Model (DEM showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°, enthalpy (∆H° and entropy (∆S° of ammonium-clinoptilolite system were estimated by using the thermodynamic equilibrium coefficients.

Sequence crystallization during isotherm evaporation of southern ...

African Journals Online (AJOL)

Southern Algerian's natural brine sampled from chott Baghdad may be a source of mineral salts with a high economic value. These salts are recoverable by simple solar evaporation. Indeed, during isothermal solar evaporation, it is possible to recover mineral salts and to determine the precipitation sequences of different ...

Kinetic and isotherm modeling of Cd (II) adsorption by L-cysteine functionalized multi-walled carbon nanotubes as adsorbent.

Science.gov (United States)

Taghavi, Mahmoud; Zazouli, Mohammad Ali; Yousefi, Zabihollah; Akbari-adergani, Behrouz

2015-11-01

In this study, multi-walled carbon nanotubes were functionalized by L-cysteine to show the kinetic and isotherm modeling of Cd (II) ions onto L-cysteine functionalized multi-walled carbon nanotubes. The adsorption behavior of Cd (II) ion was studied by varying parameters including dose of L-MWCNTs, contact time, and cadmium concentration. Equilibrium adsorption isotherms and kinetics were also investigated based on Cd (II) adsorption tests. The results showed that an increase in contact time and adsorbent dosage resulted in increase of the adsorption rate. The optimum condition of the Cd (II) removal process was found at pH=7.0, 15 mg/L L-MWCNTs dosage, 6 mg/L cadmium concentration, and contact time of 60 min. The removal percent was equal to 89.56 at optimum condition. Langmuir and Freundlich models were employed to analyze the experimental data. The data showed well fitting with the Langmuir model (R2=0.994) with q max of 43.47 mg/g. Analyzing the kinetic data by the pseudo-first-order and pseudo-second-order equations revealed that the adsorption of cadmium using L-MWSNTs following the pseudo-second-order kinetic model with correlation coefficients (R2) equals to 0.998, 0.992, and 0.998 for 3, 6, and 9 mg/L Cd (II) concentrations, respectively. The experimental data fitted very well with the pseudo-second-order. Overall, treatment of polluted solution to Cd (II) by adsorption process using L-MWCNT can be considered as an effective technology.

Natural convection in a horizontal channel provided with heat generating blocks: Discussion of the isothermal blocks validity

International Nuclear Information System (INIS)

Mouhtadi, D.; Amahmid, A.; Hasnaoui, M.; Bennacer, R.

2012-01-01

Highlights: ► We examine the validity of isothermal model for blocks with internal heat generation. ► Criteria based on comparison of total and local quantities are adopted. ► Thermal conductivity and Biot number required for the validity of the isothermal model are dependent on the Rayleigh number. ► The validity conditions are also affected by the multiplicity of solutions. - Abstract: This work presents a numerical study of air natural convection in a horizontal channel provided with heating blocks periodically distributed on its lower adiabatic surface. The blocks are submitted to a uniform heat generation and the channel upper surface is maintained at a cold constant temperature. The main objective of this study is to examine the validity of the model with isothermal blocks for the system under consideration. Then the calculations are performed using two different models. In the first (denoted Model 1 or M1) the calculations are performed by imposing a uniform volumetric heat generation inside the blocks. In the second model (denoted Model 2 or M2), the blocks are maintained isothermal at the average blocks surface temperature deduced from the Model 1. The controlling parameters of the present problem are the thermal conductivity ratio of the solid block and the fluid (0.1 ⩽ k* = k s /k a ⩽ 200) and the Rayleigh number (10 4 ⩽ Ra ⩽ 10 7 ). The validity of the isothermal model is examined for various Ra by using criteria based on local and mean heat transfer characteristics. It is found that some solutions of the isothermal model do not reproduce correctly the results of the first model even for very large conductivity ratios. The Biot number below which the Model 2 is valid depends strongly on the Rayleigh number and the type of solution.

Isotherms of Capillary Condensation Influenced by Formation of Adsorption Films.

Science.gov (United States)

Churaev; Starke; Adolphs

2000-01-15

Isotherms of capillary condensation are often used to determine the vapor sorption capacity of porous adsorbents as well as the pore size distribution by radii. In this paper, for calculating the volume of capillary condensate and of adsorption films in a porous body, an approach based on the theory of surface forces is used. Adsorption isotherms and disjoining pressure isotherms of wetting films are presented here in an exponential form discussed earlier. The calculations were made for straight cylindrical capillaries of different radii and slit pores of different width. The mechanisms of capillary condensation differ in cylindrical and slit pores. In cylindrical pores capillary condensation occurs due to capillary instability of curved wetting films on a capillary surface, when film thickness grows. In the case of slit pores, coalescence of wetting films formed on opposite slit surfaces proceeds under the action of attractive dispersion forces. Partial volumes of liquid in the state of both capillary condensate and adsorbed films are calculated dependent on the relative vapor pressure in a surrounding media. Copyright 2000 Academic Press.

Adsorption of selected emerging contaminants onto PAC and GAC: Equilibrium isotherms, kinetics, and effect of the water matrix.

Science.gov (United States)

Real, Francisco J; Benitez, F Javier; Acero, Juan L; Casas, Francisco

2017-07-03

The removal of three emerging contaminants (ECs) (amitriptyline hydrochloride (AH), methyl salicylate (MS) and 2-phenoxyethanol (PE)) dissolved in several water matrices by means of their adsorption onto powdered activated carbon (PAC) and granular activated carbon (GAC) has been investigated. When dissolved in ultrapure water, adsorption of the ECs followed the trend of AH > MS > PE, with a positive effect of the adsorbent dose. According to the analysis of the adsorption isotherms and adsorption kinetics, PAC showed strongly higher adsorption efficiency in both capacity and velocity of the adsorption, in agreement with its higher mesoporosity. Equilibrium isotherm data were fitted by Langmuir and Freundlich models. Pseudo-second order kinetics modeled very successfully the adsorption process. Finally, the effect of the presence of dissolved organic matter (DOM) in the water matrices (ultrapure water, surface water and two effluents from wastewater treatment plants) on the adsorption of the selected ECs onto PAC was established, as well as its performance on the removal of water quality parameters. Results show a negative effect of the DOM content on the adsorption efficiency. Over 50% of organic matter was removed with high PAC doses, revealing that adsorption onto PAC is an effective technology to remove both micro-pollutants and DOM from water matrices.

Sorption of Lead (Pb from Aqueous Solutions by Sepiolite and Bentonite Modified with Chitosan Biopolymers: Isotherms and Kinetics

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Hamid Reza Rafiei

2016-07-01

Full Text Available In this study, sepiolite and bentonite clay minerals were modified with a natural chitosan biopolymer and the modified-clays were characterized using XRF, XRD, FTIR, SEM, and TOC analyses. The isothermal and kinetic parameters of lead (Pb sorption by both the minerals and the modified-minerals were determined in a batch mode under various conditions such as different contact times and initial concentrations of Pb. It was found that the Freundlich model described well the isotherm experimental data of Pb sorption by the sorbents. Modification with chitosan, however, decreased the Pb adsorption capacity of sepiolite from 83 to 27 mg g-1 and that of bentonite from 56 to 29 mg g-1. Kinetic results showed that more than 24 hours was required for Pb sorption by the natural clays to reach equilibrium, while the equilibrium time reduced to 16 and 4 hours for Pb sorption on chitosan-sepiolite and chitosan–bentonite, respectively. The pseudo-second-order model well described the time-dependent Pb sorption data by sepiolite, chitosan-sepiolite, and chitosan-bentonite, suggesting that chemical sorption is the rate-limiting step of Pb adsorption mechanism. The Pb sorption data by bentonite showed the best fit with Elovich model.

Removal of metal ions from water using nanohydrogel tragacanth gum-g-polyamidoxime: isotherm and kinetic study.

Science.gov (United States)

Masoumi, Arameh; Ghaemy, Mousa

2014-08-08

A new biosorbent was prepared by grafting polyacrylonitrile onto iranian tragacanth gum (ITG), a naturally and abundantly available polysaccharide, and subsequent amidoximation in the presence of hydroxylamine hydrochloride. This nanohydrogel with amidoxime functional groups [C(NH2)NOH], named polyamidoxime-g-tragacanth (ITG-g-PAO), was characterized and used for the removal of metal ions from aqueous solution. The effect of pH, agitation time, concentration of adsorbate and amount of adsorbent on the extent of adsorption was investigated. The experimental data were analyzed by four isotherms and kinetics equations, and the results were fitted well with the Temkin isotherm and pseudo-second-order model. The maximum adsorption capacities (Qm) of ITG-g-PAO as obtained from Langmuir adsorption isotherm were found to be 100.0, 76.92, 71.42 and 66.67 (mgg(-1)) for the adsorption of metal ions in order of Co(II)>Zn(II)>Cr(III)>Cd(II). The experimental results demonstrate that the above selective order of adsorption capacity is due to formation of stable chelating ring between the bidentate amidoxime ligand and metal ion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prediction of water vapour sorption isotherms and microstructure of hardened Portland cement pastes

International Nuclear Information System (INIS)

Burgh, James M. de; Foster, Stephen J.; Valipour, Hamid R.

2016-01-01

Water vapour sorption isotherms of cementitious materials reflect the multi-scale physical microstructure through its interaction with moisture. Our ability to understand and predict adsorption and desorption behaviour is essential in the application of modern performance-based approaches to durability analysis, along with many other areas of hygro-mechanical and hygro-chemo-mechanical behaviour. In this paper, a new physically based model for predicting water vapour sorption isotherms of arbitrary hardened Portland cement pastes is presented. Established thermodynamic principles, applied to a microstructure model that develops with hydration, provide a rational basis for predictions. Closed-form differentiable equations, along with a rational consideration of hysteresis and scanning phenomena, makes the model suitable for use in numerical moisture simulations. The microstructure model is reconciled with recently published 1 H NMR and mercury intrusion porosimetry results.

Isothermal curing of polymer layered silicate nanocomposites based upon epoxy resin by means of anionic homopolymerisation

International Nuclear Information System (INIS)

Román, Frida; Calventus, Yolanda; Colomer, Pere; Hutchinson, John M.

2013-01-01

Highlights: • The nanocomposite with low content of clay displayed improved thermal properties. • The vitrification was observed in the isothermal curing. • Dielectric relaxations outside and inside of the clay galleries were detected. - Abstract: The use of an initiator, 4-(dimethylamino) pyridine (DMAP), to promote an anionic homopolymerisation reaction for the isothermal cure of polymer layered silicate (PLS) nanocomposites based on an epoxy resin, as well as the effect of the nanoclay content, have been studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dielectric relaxation spectroscopy (DRS) and transmission electron microscopy (TEM). The vitrification phenomenon was observed during the isothermal cure process, and it was found that the nanocomposite with a low clay content (2 wt%), denoted EDM2, shows improved thermal properties with respect to the unreinforced resin (denoted ED), while the nanocomposite with a higher clay content (5 wt%), denoted EDM5, displayed inferior properties. The cure kinetics were analysed by different methods, and it was observed that the activation energy and kinetic parameters of EDM2 were lower compared to the other two systems. Examination of the nanostructure of the cured EDM2 nanocomposite showed partial exfoliation, while the EDM5 system retains an intercalated nanostructure. In the DRS studies of the curing process of the EDM2 system, two dielectric relaxations were detected, which are associated with the molecular mobility in the curing reaction which takes place both outside and inside the clay galleries

Biosorption of the Copper and Cadmium Ions - a Study through Adsorption Isotherms Analysis

Directory of Open Access Journals (Sweden)

Marcia T. Veit

2007-10-01

Full Text Available In this work, the biosorption process of copper-cadmium ions binary mixture by using marine algae Sargassum filipendula was investigated. A set of experiments was performed to obtain equilibrium data for the given batch operational conditions - T=30°C, pH=5. The interpretation of equilibrium data was based on the binary adsorption isotherms models in the Langmuir and Freundlich forms. To evaluate the models parameters, nonlinear identification procedure was used based on the Least Square statistical method and SIMPLEX local optimizer. An analysis of the obtained results showed that the marine algae biomass has higher affinity to copper ions than to cadmium ones. The biomass maximum adsorption capacity for the binary system was about 1.16 meq/g.

The impact of non-isothermal soil moisture transport on evaporation fluxes in a maize cropland

Science.gov (United States)

Shao, Wei; Coenders-Gerrits, Miriam; Judge, Jasmeet; Zeng, Yijian; Su, Ye

2018-06-01

The process of evaporation interacts with the soil, which has various comprehensive mechanisms. Multiphase flow models solve air, vapour, water, and heat transport equations to simulate non-isothermal soil moisture transport of both liquid water and vapor flow, but are only applied in non-vegetated soils. For (sparsely) vegetated soils often energy balance models are used, however these lack the detailed information on non-isothermal soil moisture transport. In this study we coupled a multiphase flow model with a two-layer energy balance model to study the impact of non-isothermal soil moisture transport on evaporation fluxes (i.e., interception, transpiration, and soil evaporation) for vegetated soils. The proposed model was implemented at an experimental agricultural site in Florida, US, covering an entire maize-growing season (67 days). As the crops grew, transpiration and interception became gradually dominated, while the fraction of soil evaporation dropped from 100% to less than 20%. The mechanisms of soil evaporation vary depending on the soil moisture content. After precipitation the soil moisture content increased, exfiltration of the liquid water flow could transport sufficient water to sustain evaporation from soil, and the soil vapor transport was not significant. However, after a sufficient dry-down period, the soil moisture content significantly reduced, and the soil vapour flow significantly contributed to the upward moisture transport in topmost soil. A sensitivity analysis found that the simulations of moisture content and temperature at the soil surface varied substantially when including the advective (i.e., advection and mechanical dispersion) vapour transport in simulation, including the mechanism of advective vapour transport decreased soil evaporation rate under wet condition, while vice versa under dry condition. The results showed that the formulation of advective soil vapor transport in a soil-vegetation-atmosphere transfer continuum can

Moisture sorption isotherms of dehydrated whey proteins

Directory of Open Access Journals (Sweden)

Suzana Rimac Brnčić

2010-03-01

Full Text Available Moisture sorption isotherms describe the relation between the moisture content of the dry material (food and relative humidity of the surrounding environment. The data obtained are important in modelling of drying process conditions, packaging and shelf-life stability of food that will provide maximum retaining of aroma, colour and texture as well as nutritive and biological value. The objective of this research was to establish the equilibrium moisture content and water activity, as well as monolayer value of two commercial powdered whey protein isolates before and after tribomechanical micronisation and enzymatic hydrolysis, respectively. At the same time it was necessary to evaluate the best moisture sorption isotherm equation to fit the experimental data. The equilibrium moisture contents in investigated samples were determined using standard gravimetric method at 20 °C. The range of water activities was 0.11 to 0.75. The monolayer moisture content was estimated from sorption data using Brunauer-Emmett-Teller (BET and Guggenheim-Anderson-de Boer (GAB models. The results have shown that tribomechanically treated whey protein isolates as well as protein hydrolizates had lower monolayer moisture content values as well as higher corresponding water activity. Therefore, in spite of the fact that they have lower moisture content, they can be storage at higher relative humidity compared to untreated samples. BET model gave better fit to experimental sorption data for a water activity range from 0.11-0.54, while GAB model gave the closest fit for a water activity to 0.75.

Computation of two-dimensional isothermal flow in shell-and-tube heat exchangers

International Nuclear Information System (INIS)

Carlucci, L.N.; Galpin, P.F.; Brown, J.D.; Frisina, V.

1983-07-01

A computational procedure is outlined whereby two-dimensional isothermal shell-side flow distributions can be calculated for tube bundles having arbitrary boundaries and flow blocking devices, such as sealing strips, defined in arbitrary locations. The procedure is described in some detail and several computed results are presented to illustrate the robustness and generality of the method

Construction of isotherms in solvent extraction of copper

Directory of Open Access Journals (Sweden)

Cvetkovski Vladimir B.

2009-01-01

Full Text Available The aim of this work is construction of equilibrium isotherms in solvent extraction. Technological parameters have been predicted for treatment of mine water by solvent extraction and electrowining. Two stages of extractions and one stage of stripping have been predicted for copper recovery by analyzing the equilibrium isotherms. The process was performed on mine water with 2,5 g/dm3 Cu2+, 3 g/dm Fe2+, pH 1,8, using 9 vol% LIX 984N in kerosene (organic solvent, with 95 and 98% stages efficiencies, respectively. This course produced an advanced electrolyte solution, suitable for electrowining and cathodic copper recovery, containing 51 g/dm3 Cu2+ and 160g/dm3 H2SO4 from a 30 g/dm3 Cu and 190 g/dm3 H2SO4.

Removal of 2,4-dichlorophenol using cyclodextrin-ionic liquid polymer as a macroporous material: Characterization, adsorption isotherm, kinetic study, thermodynamics

Energy Technology Data Exchange (ETDEWEB)

Raoov, Muggundha [University of Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Advanced Medical and Dental Institute, University of Science Malaysia, No. 1–8 (Lot 8), Persiaran Seksyen 4/1, Bandar Putra Bertam, Kepala Batas, Pulau Pinang 13200 (Malaysia); Mohamad, Sharifah, E-mail: sharifahm@um.edu.my [University of Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Abas, Mohd Radzi [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

2013-12-15

Highlights: • βCD-BIMOTs-TDI exhibits macropore size (77.66 nm) with 1.254 m{sup 2} g{sup −1} surface area. • Freundlich isotherm and pseudo-second order kinetics fit well the adsorption process. • Removal was optimum at pH 6 with 83% and reached equilibrium at 80 mg L{sup −1}. • Entropy (ΔS°) and heat of adsorption (ΔH°) estimated as −55.99 J/K mol and −18.10 J/mol. • Inclusion complex and π–π interaction were found to be dominant at pH 6. -- Abstract: Cyclodextrin-ionic liquid polymer (βCD-BIMOTs-TDI) was firstly synthesized using functionalized β-Cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs) and was further polymerized using toluene diisocyanate (TDI) linker to form insoluble βCD-BIMOTs-TDI. SEM characterization result shows that βCD-BIMOTs-TDI exhibits macropore size while the BET result shows low surface area (1.254 m{sup 2} g{sup −1}). The unique properties of the ILs allow us to produce materials with different morphologies. The adsorption isotherm and kinetics of 2,4-dichlorophenol (2,4-DCP) onto βCD-BIMOTs-TDI is studied. Freundlich isotherm and pseudo-second order kinetics are found to be the best to represent the data for 2,4-DCP adsorption on the βCD-BIMOTs-TDI. The presence of macropores decreases the mass transfer resistance and increases the adsorption process by reducing the diffusion distance. The change in entropy (ΔS°) and heat of adsorption (ΔH°) for 2,4-DCP on βCD-BIMOTs-TDI were estimated as −55.99 J/Kmol and −18.10 J/mol, respectively. The negative value of Gibbs free energy (ΔG°) indicates that the adsorption process is thermodynamically feasible, spontaneous and chemically controlled. Finally, the interactions between the cavity of βCD-BIMOTs and 2,4-DCP are investigated and the results shows that the inclusion of the complex formation and π–π interaction are the main processes involved in the adsorption process.

Isothermal Titration Calorimetry in the Student Laboratory

Science.gov (United States)

Wadso, Lars; Li, Yujing; Li, Xi

2011-01-01

Isothermal titration calorimetry (ITC) is the measurement of the heat produced by the stepwise addition of one substance to another. It is a common experimental technique, for example, in pharmaceutical science, to measure equilibrium constants and reaction enthalpies. We describe a stirring device and an injection pump that can be used with a…

arXiv Isothermal compressibility of hadronic matter formed in relativistic nuclear collisions

CERN Document Server

Mukherjee, Maitreyee; Chatterjee, Arghya; Chatterjee, Sandeep; Adhya, Souvik Priyam; Thakur, Sanchari; Nayak, Tapan K.

We present the first estimates of isothermal compressibility (\\kT) of hadronic matter formed in relativistic nuclear collisions (\\sNN=7.7~GeV to 2.76~TeV) using experimentally observed quantities. \\kT~is related to the fluctuation in particle multiplicity, temperature and volume of the system formed in the collisions. Multiplicity fluctuations are obtained from the event-by-event distributions of charged particle multiplicities in narrow centrality bins. The dynamical components of the fluctuations are extracted by removing the contributions to the fluctuations from the number of participating nucleons. From the available experimental data, a constant value of \\kT~has been observed as a function of collision energy. The results are compared with calculations from UrQMD, AMPT and EPOS event generators, and estimations of \\kT~are made for Pb-Pb collisions at the CERN Large Hadron Collider. A hadron resonance gas (HRG) model has been used to calculate \\kT~as a function of collision energy. Our results show a dec...

Microfluidic method for rapid turbidimetric detection of the DNA of Mycobacterium tuberculosis using loop-mediated isothermal amplification in capillary tubes

International Nuclear Information System (INIS)

Rafati, Adele; Gill, Pooria

2015-01-01

We describe a microfluidic method for rapid isothermal turbidimetric detection of the DNA of Mycobacterium tuberculosis. Loop-mediated isothermal amplification is accomplished in capillary tubes for amplifying DNA in less than 15 min, and sensitivity and specificity were compared to conventional loop-mediated isothermal amplification (LAMP). The method can detect as little as 1 pg mL −1 DNA in a sample. Results obtained with clinical specimens indicated 90 % sensitivity and 95 % specificity for microfluidic LAMP in comparison to culture methods. No interference occurred due to the presence of nonspecific DNAs. The findings demonstrate the power of the new microfluidic LAMP test for rapid molecular detection of microorganisms even when using bare eyes. (author)

MODELING OF ISOTHERMAL PRECIPITATION KINETICS IN HSLA STEELS AND ITS APPLICATION

Institute of Scientific and Technical Information of China (English)

X.M. Zhao; D. Wu; L.Z. Zhang; Z.Y. Liu

2004-01-01

Microalloying elements in high-strength low-alloy steels, such as Nb, Ti and V, precipitate during hot-rolling processes. On the basis of classical theory of nucleation and growth, quantitative modeling of isothermal precipitation was developed, which was tested by the stress relaxation method, the calculated precipitation-time-temperature curve is in good agreements with the measured results, then the model was applied to predict the precipitation behavior during continuous cooling.

Determination of adsorption isotherms of chlorinated hydrocarbons on halloysite adsorbent by inverse gas chromatography.

Science.gov (United States)

Czech, K; Słomkiewicz, P M

2013-05-03

Inverse gas chromatographic methods of isotherm determination peak maximum (PM) and peak division (PD) were compared. These methods were applied to determine adsorption isotherms of dichloroethylene, trichloroethylene and tetrachloroethylene on acid-activated halloysite and adsorption enthalpy. Copyright © 2013 Elsevier B.V. All rights reserved.

Sorption of alkylphenols on Ebro River sediments: Comparing isotherms with field observations in river water and sediments

International Nuclear Information System (INIS)

Navarro, Alicia; Endo, Satoshi; Gocht, Tilman; Barth, Johannes A.C.; Lacorte, Silvia; Barcelo, Damia; Grathwohl, Peter

2009-01-01

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f OC ) ranging from 0.0035 to 0.082 g OC g -1 . All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations. - Laboratory sorption of nonylphenol compared to field concentrations showed good agreements

Sorption of alkylphenols on Ebro River sediments: Comparing isotherms with field observations in river water and sediments

Energy Technology Data Exchange (ETDEWEB)

Navarro, Alicia [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain)], E-mail: anoqam@iiqab.csic.es; Endo, Satoshi; Gocht, Tilman [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Barth, Johannes A.C. [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Lehrstuhl fuer Angewandte Geologie, GeoZentrum Nordbayern, Universitaet Erlangen-Nuernberg, Schlossgarten 5, 91054 Erlangen (Germany); Lacorte, Silvia [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Barcelo, Damia [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Institut Catala de Recerca de l' Aigua (ICRA), Parc Cientific i Tecnologic de la Universitat de Girona, Pic de Peguera, 15, 17003 Girona (Spain); Grathwohl, Peter [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany)

2009-02-15

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f{sub OC}) ranging from 0.0035 to 0.082 g{sub OC} g{sup -1}. All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations. - Laboratory sorption of nonylphenol compared to field concentrations showed good agreements.

Direct measurement of the lethal isotherm for radiofrequency ablation of myocardial tissue.

Science.gov (United States)

Wood, Mark; Goldberg, Scott; Lau, Melissa; Goel, Aneesh; Alexander, Daniel; Han, Frederick; Feinstein, Shawn

2011-06-01

The lethal isotherm for radiofrequency catheter ablation of cardiac myocardium is widely accepted to be 50°C, but this has not been directly measured. The purpose of this study was to directly measure the tissue temperature at the edge of radiofrequency lesions in real time using infrared thermal imaging. Fifteen radiofrequency lesions of 6 to 240 seconds in duration were applied to the left ventricular surface of isolated perfused pig hearts. At the end of radiofrequency delivery, a thermal image of the tissue surface was acquired with an infrared camera. The lesion was then stained and an optical image of the lesion was obtained. The thermal and optical images were electronically merged to allow determination of the tissue temperature at the edge of the lesion at the end of radiofrequency delivery. By adjusting the temperature overlay display to conform with the edge of the radiofrequency lesion, the lethal isotherm was measured to be 60.6°C (interquartile ranges, 59.7° to 62.4°C; range, 58.1° to 64.2°C). The areas encompassed by the lesion border in the optical image and the lethal isotherm in the thermal image were statistically similar and highly correlated (Spearman ρ=0.99, Pradiofrequency delivery or to lesion size (both P>0.64). The areas circumscribed by 50°C isotherms were significantly larger than the areas of the lesions on optical imaging (P=0.002). By direct measurement, the lethal isotherm for cardiac myocardium is near 61°C for radiofrequency energy deliveries radiofrequency ablation is important to clinical practice as well as mathematical modeling of radiofrequency lesions.

Isothermal, kinetic and thermodynamic studies on basic dye sorption ...

African Journals Online (AJOL)

Isothermal, kinetic and thermodynamic studies on basic dye sorption onto tartaric acid esterified wheat straw. ... African Journal of Biotechnology ... esterified wheat straw (EWS), was originally prepared by solid phase thermochemistry method.

Spectral and directional radiation characteristics of thin-film coated isothermal semitransparent plates

Energy Technology Data Exchange (ETDEWEB)

Taylor, R P; Viskanta, R

1975-01-01

An analysis is presented for predicting the effective spectral directional radiation characteristics of an isothermal, semitransparent sheet surrounded on both sides by massive dielectrics. The sheet can be coated with an optically thin film and used as selective cover plates for solar collectors. Directional and polarization effects and the spectral transmittance and reflectance are considered. Sample results for candidate materials are presented.

Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C

Directory of Open Access Journals (Sweden)

Jitka Langová

2012-01-01

Full Text Available Moisture sorption isotherms (MSI’s of skimmed milk powder in the temperature range of 5–20 °C were determined using manometric method. MSI’s, which show the water content versus water activity (Aw at a constant temperature, are used to describe relationships between water content and equilibrium state relative vapour pressure (RVP. The equilibrium moisture content (EMC of skimmed milk powder samples is growing with an increase of Aw at a constant temperature both for water adsorption and desorption. Isotherms were found to be type II of Brunauer-Emmett-Teller classification. It is the type most common for foods. The shape of created isotherms was sigmoid. Structural modifications of crystals were observed during adsorption in the microscope, too. Critical value of EMC of tested samples corresponding to the Aw equal to 0.6 for adsorption was 6.50% MC (w.b. at temperature 5 °C, 9.15% MC (w.b. at temperature 10 °C, and 7.71% MC (w.b. at temperature 20 °C. These values determine optimal conditions for storage from the point of view microorganisms grow, Aw<0.6.

Isotopic composition of precipitations in Brazil: isothermic models and the influence of evapotranspiration in the Amazonic Basin

International Nuclear Information System (INIS)

Dall'Olio, Attilio.

1976-11-01

The simplest theoretical models of the isotopic fractionation of water during equilibrium isothermical processes are analized in detail. The theoretical results are applied to the interpretation of the stable isotope concentrations in the precipitations of 11 Brazilian cities that belong to the international network of IAEA/WMO. The analysis shows that the experimental data are fairly consistent with such equilibrium models; no non-equilibrium processes need to be assumed. The study of the stable isotope content of precipitations in the Amazonic Basin suggests some modifications to the models in order that the evapotranspiration contribution to the vapour balance be taken into account [pt

Analysis of a self-propelling sheet with heat transfer through non-isothermal fluid in an inclined human cervical canal.

Science.gov (United States)

Walait, Ahsan; Siddiqui, A M; Rana, M A

2018-02-13

The present theoretical analysis deals with biomechanics of the self-propulsion of a swimming sheet with heat transfer through non-isothermal fluid filling an inclined human cervical canal. Partial differential equations arising from the mathematical modeling of the proposed model are solved analytically. Flow variables like pressure gradient, propulsive velocity, fluid velocity, time mean flow rate, fluid temperature, and heat-transfer coefficients are analyzed for the pertinent parameters. Striking features of the pumping characteristics are explored. Propulsive velocity of the swimming sheet becomes faster for lower Froude number, higher Reynolds number, and for a vertical channel. Temperature and peak value of the heat-transfer coefficients below the swimming sheet showed an increase by the increment of Brinkmann number, inclination, pressure difference over wavelength, and Reynolds number whereas these quantities decrease with increasing Froude number. Aforesaid parameters have shown opposite effects on the peak value of the heat-transfer coefficients below and above the swimming sheet. Relevance of the current results to the spermatozoa transport with heat transfer through non-isothermal cervical mucus filling an inclined human cervical canal is also explored.

Local galactic kinematics: an isothermal model

International Nuclear Information System (INIS)

Nunez, J.

1983-01-01

The kinematical parameters of galactic rotation in the solar neighborhood and the corrections to the precession have been calculated. For this purpose, an isothermal model for the solar neighborhood has been used together with the high order momenta of the local stellar velocity distribution and the Ogorodnikov-Milne model. Both have been calculated using some samples of the ''512 Distant FK4/FK4 Sup. Stars'' of Fricke (1977) and of Gliese's Gatalogue. (author)

Effects of magnetic field and hydrostatic pressure on the isothermal martensitic transformation in an Fe-25.0Ni-4.0Cr alloy

International Nuclear Information System (INIS)

Kakeshita, T.; Saburi, T.; Shimizu, K.

1995-01-01

Effects of magnetic fields and hydrostatic pressures on the isothermal martensitic transformation, whose nose temperature is about 140K, in an Fe-25.0Ni-4.0Cr alloy (mass%) has been examined by applying magnetic fields up to 30MA/m and hydrostatic pressures up to 1.5GPa. The obtained results are the following: The martensitic transformation is induced instantaneously (less than 20μsec.) under pulsed magnetic fields higher than a critical field over a wide temperature range between 4.2 and 200K. The critical magnetic field increases with increasing temperature, and the relation between critical magnetic field and temperature is in good agreement with the one calculated by the equation previously derived by the authors. The T T T diagram under static magnetic field shows a lower nose temperature and a shorter incubation time than that under no external magnetic field, while the T T T diagram under hydrostatic pressure shows a higher nose temperature and a longer incubation time than that under no external hydrostatic pressure. These results are well explained by the new phenomenological theory, which gives a unified explanation on the isothermal and athermal kinetics of martensitic transformations previously constructed by the authors. (orig.)

Kink Waves in Non-isothermal Stratified Solar Waveguides: Effect of the External Magnetic Field

Energy Technology Data Exchange (ETDEWEB)

Lopin, I. [Ussuriisk Astrophysical Observatory, Russian Academy of Sciences (Russian Federation); Nagorny, I., E-mail: lopin78@mail.ru [Institute of Automation and Control Processes FEB RAS, Vladivostok (Russian Federation)

2017-10-01

We study the effect of an external magnetic field on the properties of kink waves, propagating along a thin non-isothermal stratified and diverging magnetic flux tube. A wave equation, governing the propagation of kink waves under the adopted model is derived. It is shown that the vertical gradient of temperature introduces a spatially local cut-off frequency ω {sub c}. The vertical distribution of the cut-off frequency is calculated for the reference VAL-C model of the solar atmosphere and for different values of a ratio of external to internal magnetic fields. The results show that the cut-off frequency is negative below the temperature minimum due to the negative temperature gradient. In the chromosphere the cut-off frequency at a given height is smaller for a stronger external magnetic field. For the appropriate range of a ratio B{sub e} / B{sub i}  ≈ 0–0.8, the cutoff lies in the range ω{sub c}  ≈ 0.003–0.010 s{sup −1} (periods 600 < P{sub c} < 2000 s). The estimate of the cut-off frequency in the transition region is provided as well. In the propagating wave regime, the effective wave energy flux in the non-isothermal diverging flux tubes is the same as in the straight and homogeneous cylindrical waveguides. The obtained wave equation in the limit β  = 0 is used to study the kink oscillations of non-isothermal coronal loops. It is found that the gradient of temperature along the coronal loops reduces the frequency ratio of the first overtone to the fundamental mode, i.e., ω{sub 2}/ ω{sub 1} < 2. This reduction grows for a larger ratio of temperature at the loop top to the temperature at the footpoints. Moreover, the effect of reduction is most pronounced for the steeper temperature profiles.

Development of loop-mediated isothermal amplification method for ...

African Journals Online (AJOL)

A novel assay method to detect the highly virulent Porcine reproductive and respiratory syndrome virus (PRRSV) termed reverse transcriptase loop-mediated isothermal amplification (RT-LAMP), was reported by using hydroxynaphthol blue (HNB) as the LAMP product colorimetric judgment. By the set of special primers, ...

Loop-mediated isothermal amplification (LAMP) shield for Arduino DNA detection.

Science.gov (United States)

Velders, Aldrik H; Schoen, Cor; Saggiomo, Vittorio

2018-02-01

Loop-mediated isothermal amplification (LAMP) of DNA is gaining relevance as a method to detect nucleic acids, as it is easier, faster, and more powerful than conventional Polymerase Chain Reaction. However, LAMP is still mostly used in laboratory settings, because of the lack of a cheap and easy, one-button device that can perform LAMP experiments. Here we show how to build and program an Arduino shield for a LAMP and detection of DNA. The here described Arduino Shield is cheap, easy to assemble, to program and use, it is battery operated and the detection of DNA is done by naked-eye so that it can be used in field.

Adsorption kinetics, isotherm, and thermodynamics studies of acetyl-11-keto-β-boswellic acids (AKBA) from Boswellia serrata extract using macroporous resin.

Science.gov (United States)

Niphadkar, Sonali S; Rathod, Virendra K

2017-09-14

An acetyl-11-keto-β-boswellic acid (AKBA) is potent anti-inflammatory agent found in Boswellia serrata oleogum resin. Adsorption characteristics of AKBA from B. serrata were studied using macroporous adsorbent resin to understand separation and adsorption mechanism of targeted molecules. Different macroporous resins were screened for adsorption and desorption of AKBA and Indion 830 was screened as it showed higher adsorption capacity. The kinetic equations were studied and results showed that the adsorption of AKBA on Indion 830 was well fitted to the pseudo first-order kinetic model. The influence of two parameters such as temperature (298, 303, and 308 K) and pH (5-8) on the adsorption process was also studied. The experimental data was further investigated using Langmuir, Freundlich, and Temkin isotherm models. It was observed that Langmuir isotherm model was found to be the best fit for AKBA adsorption by Indion 830 and highest adsorption capacity (50.34 mg/g) was obtained at temperature of 303 K. The values of thermodynamic parameters such as the change of Gibbs free energy (ΔG*), entropy (ΔS*), and enthalpy (ΔH*), indicated that the process of adsorption was spontaneous, favourable, and exothermic.

Adsorption isotherme de l'acide acétique par des charbons d'origine ...

African Journals Online (AJOL)

The adsorption properties of six samples of carbons of which two are obtained from AYOUS (Triplochiton Scléroxylon), two from AKOM (Terminalia Superba) and two obtained commercially were studied from their adsorption isotherms of acetic acid at 30° and 45°C. This study has resulted in the determination of the two ...

Isothermal thermogravimetric data acquisition analysis system

Science.gov (United States)

Cooper, Kenneth, Jr.

1991-01-01

The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

A numerical study of non-isothermal turbulent coaxial jets

Energy Technology Data Exchange (ETDEWEB)

Kriaa, Wassim; Abderrazak, Kamel; Mhiri, Hatem [Ecole Nationale d' Ingenieurs de Monastir, Laboratoire de Mecanique des Fluides et Thermique, Monastir (Tunisia); Palec, Georges le; Bournot, Philippe [Institut de Mecanique de Marseille, Marseille (France)

2008-07-15

In this work, we propose to study non isothermal air-air coaxial jets with two different approaches: parabolic and elliptic approaches. The standard k-{epsilon} model and the RSM model were applied in this study. The numerical resolution of the equations governing this flow type was carried out for: the parabolic approach, by a ''home-made'' CFD code based on a finite difference method, and the elliptic approach by an industrial code (FLUENT) based on a finite volume method. In forced convection mode (Fr={infinity}), the two turbulence models are valid for the prediction of the mean flow. But for turbulent sizes, k-{epsilon} model gives results closer to those achieved in experiments compared to RSM Model. Concerning the limit of validity of the parabolic and elliptic approaches, we showed that for velocities ratio r lower than 1, the results of the two approaches were satisfactory. On the other hand, for r>1, the difference between the results became increasingly significant. In mixed convection mode (Fr{approx_equal}20), the results obtained by the two turbulence models for the mean axial velocity were very different even in the plume region. For the temperature and the turbulent sizes the two models give satisfactory results which agree well with the correlations suggested by the experimenters for X{>=}20. Thus, the second order model with {sigma}{sub t}=0.85 is more effective for a coaxial jet study in a mixed convection mode. (orig.)

The 480 deg. C and 405 deg. C isothermal sections of the phase diagram of Fe-Zn-Si ternary system

Energy Technology Data Exchange (ETDEWEB)

Wang Jianhua [Institute of Materials Research, School of Mechanical Engineering, Xiangtan University, Hunan 411105 (China)]. E-mail: super_wang111@hotmail.com; Su Xuping [Institute of Materials Research, School of Mechanical Engineering, Xiangtan University, Hunan 411105 (China); Yin Fucheng [Institute of Materials Research, School of Mechanical Engineering, Xiangtan University, Hunan 411105 (China); Li Zhi [Institute of Materials Research, School of Mechanical Engineering, Xiangtan University, Hunan 411105 (China); Zhao Manxiu [Institute of Materials Research, School of Mechanical Engineering, Xiangtan University, Hunan 411105 (China)

2005-08-16

The 480 deg. C and 405 deg. C isothermal sections of the Fe-Zn-Si ternary phase diagram have been determined experimentally using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray diffractometry. The research of the work has concentrated on the Zn-rich corner, which is relevant to general galvanizing. The present studies have confirmed the existence of equilibrium state between the liquid, the {zeta} phase and the FeSi phase at the 480 deg. C isothermal section. There exist some changes in the phase relationships compared with the isothermal section at 450 deg. C. Experimental results indicate that Si solubility in all four Zn-Fe compounds is also limited at 480 deg. C and 405 deg. C.

Effect of prolonged isothermal heat treatment on the mechanical behavior of advanced NANOBAIN steel

Science.gov (United States)

Avishan, Behzad

2017-09-01

The microstructural evolution and consequent changes in strength and ductility of advanced NANOBAIN steel during prolonged isothermal heat-treatment stages were investigated. The microstructure and mechanical properties of nanostructured bainite were not expected to be influenced by extending the heat-treatment time beyond the optimum value because of the autotempering phenomenon and high tempering resistance. However, experimental results indicated that the microstructure was thermodynamically unstable and that prolonged austempering resulted in carbon depletion from high-carbon retained austenite and carbide precipitations. Therefore, austenite became thermally less stable and partially transformed into martensite during cooling to room temperature. Prolonged austempering did not lead to the typical tempering sequence of bainite, and the sizes of the microstructural constituents were independent of the extended heat-treatment times. This independence, in turn, resulted in almost constant ultimate tensile strength values. However, microstructural variations enhanced the yield strength and the hardness of the material at extended isothermal heat-treatment stages. Finally, although microstructural changes decreased the total elongation and impact toughness, considerable combinations of mechanical properties could still be achieved.

Monitoring of an RNA Multistep Folding Pathway by Isothermal Titration Calorimetry

OpenAIRE

Reymond, Cédric; Bisaillon, Martin; Perreault, Jean-Pierre

2009-01-01

Isothermal titration calorimetry was used to monitor the energetic landscape of a catalytic RNA, specifically that of the hepatitis delta virus ribozyme. Using mutants that isolated various tertiary interactions, the thermodynamic parameters of several ribozyme-substrate intermediates were determined. The results shed light on the impact of several tertiary interactions on the global structure of the ribozyme. In addition, the data indicate that the formation of the P1.1 pseudoknot is the lim...

Densities, isobaric thermal expansion coefficients and isothermal compressibilities of linear alkylbenzene

International Nuclear Information System (INIS)

Zhou, X; Zhang, Z Y; Zhang, Q M; Liu, Q; Ding, Y Y; Zhou, L; Cao, J

2015-01-01

We report the measurements of the densities of linear alkylbenzene at three temperatures over 4 to 23 °C with pressures up to 10 MPa. The measurements have been analysed to yield the isobaric thermal expansion coefficients and, so far for the first time, isothermal compressibilities of linear alkylbenzene. Relevance of results for current generation (i.e., Daya Bay) and next generation (i.e. JUNO) large liquid scintillator neutrino detectors are discussed. (paper)

Non-isothermal spreading of liquid drops on horizontal plates

International Nuclear Information System (INIS)

Ehrhard, P.; Davis, S.H.

1990-05-01

A viscous-liquid drop spreads on a smooth horizontal surface, which is uniformly heated or cooled. Lubrication theory is used to study thin drops subject to capillary, thermocapillary and gravity forces, and a variety of contact-angle-versus-speed conditions. It is found for isothermal drops that gravity is very important at large times and determines the power law for unlimited spreading. Predictions compare well with the experimental data on isothermal spreading for both two-dimensional and axisymmetric configurations. It is found that heating (cooling) retards (augments) the spreading process. When the advancing contact angle is zero, heating will cause the drop to spread only finitely far. For positive advancing contact angles, sufficient cooling will cause unlimited spreading. Thus, the heat transfer serves as a sentitive control on the spreading. (orig.) [de

Isothermal Amplification for MicroRNA Detection: From the Test Tube to the Cell.

Science.gov (United States)

Deng, Ruijie; Zhang, Kaixiang; Li, Jinghong

2017-04-18

groups are seeking methods based on isothermal amplification for detecting miRNA with high specificity (single-nucleotide resolution) and sensitivity (detection limit reaching femtomolar or even attomolar level). These methods have recently been demonstrated to quantify miRNA in clinical samples (tissues, serum, and plasma). Remarkably, attributed to the mild reaction conditions, isothermal amplification can be performed inside cells, which has recently enabled miRNA detection in single cells. The localized in situ amplification even enables imaging of miRNA at the single-molecule level. The single-cell miRNA profiling data clearly shows that genetically identical cells exhibit significant cell-to-cell variation in miRNA expression. The leap of miRNA detection achievements will significantly contribute to its full clinical adoption and translation and give us new insights into miRNA cellular functions and disease associations.

Molar volume and adsorption isotherm dependence of capillary forces in nanoasperity contacts.

Science.gov (United States)

Asay, David B; Kim, Seong H

2007-11-20

The magnitude of the capillary force at any given temperature and adsorbate partial pressure depends primarily on four factors: the surface tension of the adsorbate, its liquid molar volume, its isothermal behavior, and the contact geometry. At large contacting radii, the adsorbate surface tension and the contact geometry are dominating. This is the case of surface force apparatus measurements and atomic force microscopy (AFM) experiments with micrometer-size spheres. However, as the size of contacting asperities decreases to the nanoscale as in AFM experiments with sharp tips, the molar volume and isotherm of the adsorbate become very important to capillary formation as well as capillary adhesion. This effect is experimentally and theoretically explored with simple alcohol molecules (ethanol, 1-butanol, and 1-pentanol) which have comparable surface tensions but differing liquid molar volumes. Adsorption isotherms for these alcohols on silicon oxide are also reported.

Isothermal Titration Calorimetry Can Provide Critical Thinking Opportunities

Science.gov (United States)

Moore, Dale E.; Goode, David R.; Seney, Caryn S.; Boatwright, Jennifer M.

2016-01-01

College chemistry faculties might not have considered including isothermal titration calorimetry (ITC) in their majors' curriculum because experimental data from this instrumental method are often analyzed via automation (software). However, the software-based data analysis can be replaced with a spreadsheet-based analysis that is readily…

Development and application of a loop-mediated isothermal ...

African Journals Online (AJOL)

Haemophilus parasuis is the causative agent of Glässer's disease that has received much attention recently, due to the increasing economic losses this disease inflicts upon the pig industry worldwide. In this study, loop-mediated isothermal amplification method (LAMP) methodology was designed for diagnosing H.

Molar volume, thermal expansivity and isothermal compressibility of trans-decahydronaphthalene up to 200MPa and 446K

Institute of Scientific and Technical Information of China (English)

Zhu Hu-Gang; Liu Zhi-Hua; Tian Yi-Ling; Xue Yuan; Yin Liang

2005-01-01

The molar volume isotherms of trans-decahydronaphthalene (C10H18) between 293 and 446 K and at pressures from 10 to 200 MPa have been determined. A modified Tait equation of state is used to fit each experimental molar volume isotherm with a maximum average deviation of 0.029%. The thermal expansivity (cubic expansion coefficient) α and isothermal compressibility κ were determined by fitting the slopes of the isobaric curves and isotherms, respectively.The coefficients in the equation Vm = C1 + C2T + C3T2 - C4p - C5pT have been fitted with an average deviation of 1.03%.

Isothermal, kinetic and thermodynamic studies on basic dye sorption ...

African Journals Online (AJOL)

PRECIOUS

2009-12-15

Dec 15, 2009 ... The isothermal data correlated with the Langmuir model better than the. Freundlich model. ... there were two intra-particle diffusion steps in the dye sorption processes. .... rated monolayer of sorbate molecule on the sorbent.

Isothermal equilibrium pressures of Y-Th alloy-H2 system

International Nuclear Information System (INIS)

Tanase, M.; Fisher, P.W.

1985-01-01

Isothermal equilibrium pressures of the Y 4 Th (3:2 by weight) alloy-H 2 system were measured as a function of atomic composition [H]/[Y + Th] in the temperature range 580-1160 K. The isotherms have two plateaux in the pressure range 10 -2 -10 3 Pa. The first plateau region is attributed to the formation of YH 2 , and the equilibrium pressure P in pascals was found to be log P = 12.36 - 11300/T where T is in kelvins. The second plateau is attributed to the formation of ThH 2 , and the equilibrium pressure was found to be log P = 10.66 - 6891/T. In low atomic composition region the system obeys Sieverts' law. (Auth.)

Kinetic Analysis of Isothermal Decomposition Process of Sodium Bicarbonate Using the Weibull Probability Function—Estimation of Density Distribution Functions of the Apparent Activation Energies

Science.gov (United States)

Janković, Bojan

2009-10-01

The decomposition process of sodium bicarbonate (NaHCO3) has been studied by thermogravimetry in isothermal conditions at four different operating temperatures (380 K, 400 K, 420 K, and 440 K). It was found that the experimental integral and differential conversion curves at the different operating temperatures can be successfully described by the isothermal Weibull distribution function with a unique value of the shape parameter ( β = 1.07). It was also established that the Weibull distribution parameters ( β and η) show independent behavior on the operating temperature. Using the integral and differential (Friedman) isoconversional methods, in the conversion (α) range of 0.20 ≤ α ≤ 0.80, the apparent activation energy ( E a ) value was approximately constant ( E a, int = 95.2 kJmol-1 and E a, diff = 96.6 kJmol-1, respectively). The values of E a calculated by both isoconversional methods are in good agreement with the value of E a evaluated from the Arrhenius equation (94.3 kJmol-1), which was expressed through the scale distribution parameter ( η). The Málek isothermal procedure was used for estimation of the kinetic model for the investigated decomposition process. It was found that the two-parameter Šesták-Berggren (SB) autocatalytic model best describes the NaHCO3 decomposition process with the conversion function f(α) = α0.18(1-α)1.19. It was also concluded that the calculated density distribution functions of the apparent activation energies ( ddfE a ’s) are not dependent on the operating temperature, which exhibit the highly symmetrical behavior (shape factor = 1.00). The obtained isothermal decomposition results were compared with corresponding results of the nonisothermal decomposition process of NaHCO3.

Model-fitting approach to kinetic analysis of non-isothermal oxidation of molybdenite

International Nuclear Information System (INIS)

Ebrahimi Kahrizsangi, R.; Abbasi, M. H.; Saidi, A.

2007-01-01

The kinetics of molybdenite oxidation was studied by non-isothermal TGA-DTA with heating rate 5 d eg C .min -1 . The model-fitting kinetic approach applied to TGA data. The Coats-Redfern method used of model fitting. The popular model-fitting gives excellent fit non-isothermal data in chemically controlled regime. The apparent activation energy was determined to be about 34.2 kcalmol -1 With pre-exponential factor about 10 8 sec -1 for extent of reaction less than 0.5

Adsorption of phosphate from municipal effluents using cryptocrystalline magnesite: complementing laboratory results with geochemical modelling

CSIR Research Space (South Africa)

Masindi, Vhahangwele

2015-11-01

Full Text Available chemisorption. Adsorption isotherms fitted well to Langmuir adsorption isotherm than Freundlich adsorption isotherms, demonstrating monolayer adsorption. PHREEQC geochemical model showed Mg(sub3)(PO(sub4))(sub2) and MgHPO(sub4):3H(sub2)O as the phosphatebearing...

Metallographic Study of the Isothermal Transformation of Beta Phase in Zircaloy-2

Energy Technology Data Exchange (ETDEWEB)

Oestberg, G

1960-06-15

Observations of the structure of commercial zircaloy-2 have been made in the microscope showing that the high temperature beta phase is transformed isothermally at lower temperatures into alpha plus secondary precipitate. The alpha occurs mainly as Widmanstaetten plates developed by a shear mechanism. The secondary precipitate is formed from the beta - alpha structure at the phase boundary between these phases. This precipitation of particles of secondary phase occurs on account of a eutectoid reaction, alpha also being formed. A time-temperature transformation diagram has been constructed from the observations.

Interfacial Reaction and IMC Growth of an Ultrasonically Soldered Cu/SAC305/Cu Structure during Isothermal Aging

Directory of Open Access Journals (Sweden)

Yulong Li

2018-01-01

Full Text Available In order to accelerate the growth of interfacial intermetallic compound (IMC layers in a soldering structure, Cu/SAC305/Cu was first ultrasonically spot soldered and then subjected to isothermal aging. Relatively short vibration times, i.e., 400 ms and 800 ms, were used for the ultrasonic soldering. The isothermal aging was conducted at 150 °C for 0, 120, 240, and 360 h. The evolution of microstructure, the IMC layer growth mechanism during aging, and the shear strength of the joints after aging were systemically investigated. Results showed the following. (i Formation of intermetallic compounds was accelerated by ultrasonic cavitation and streaming effects, the thickness of the interfacial Cu6Sn5 layer increased with aging time, and a thin Cu3Sn layer was identified after aging for 360 h. (ii The growth of the interfacial IMC layer of the ultrasonically soldered Cu/SAC305/Cu joints followed a linear function of the square root of the aging time, revealing a diffusion-controlled mechanism. (iii The tensile shear strength of the joint decreased to a small extent with increasing aging time, owing to the combined effects of IMC grain coarsening and the increase of the interfacial IMC. (iv Finally, although the fracture surfaces and failure locations of the joint soldered with 400 ms and 800 ms vibration times show similar characteristics, they are influenced by the aging time.

Removal of reactive blue 19 dyes from textile wastewater by pomegranate seed powder: Isotherm and kinetic studies

Directory of Open Access Journals (Sweden)

Mahboobeh Dehvari

2016-01-01

Full Text Available Aims: The aim of this study was the evaluation of adsorption kinetics and equilibrium of reactive blue 19 dyes from textile synthetic wastewater by pomegranate seed powder. Materials and Methods: This study is an experimental research, which was performed in laboratory scale. In this study, the parameters such as adsorbent dose, pH and retention time, initial concentration of dye and agitation rate have been investigated. After washing and boiling of pomegranate seeds for 2 h, they dried, milled and finally pulverized by standard ASTM sieves (40-100 mesh. Maximum adsorption wave length (λmax by spectrophotometer ultra violet/visible (model SP-3000 Plus 592 nm was determined. The Langmuir, Freundlich and Temkin isotherm models and the pseudo-first-order and pseudo-second-order kinetic models were analyzed. Results: According to results, the removal efficiency with adsorbent dose, retention time and agitation rate has a direct relation. Maximum adsorption occurred in the first 60 min. The removal efficiency with initial concentration of dye and pH of solution has indirect relation. The Freundlich isotherm fits the experimental data better than the other isotherms. It was recognized that the adsorption followed by pseudo-second-order model (R2 > 0.99. Conclusion: Based on the results, pomegranate seeds as a new natural sorbent can be used in removal of dye and other environmental pollutants with desirable absorption capacity.

Wave propagation in a non-isothermal atmosphere and the solar five-minute oscillations. [Acoustic waves

Energy Technology Data Exchange (ETDEWEB)

Chiuderi, C; Giovanardi, C [Florence Univ. (Italy). Istituto di Astronomia

1979-11-01

This paper presents a detailed discussion of the properties of linear, periodic acoustic waves that propagate vertically in a non-isothermal atmosphere. In order to retain the basic feature of the solar atmosphere we have chosen a temperature profile presenting a minimum. An analytical solution of the problem is possible if T/..mu.., ..mu.. being the mean molecular weight, varies parabolically with height. The purpose of this study is to point out the qualitative differences existing between the case treated here and the customary analysis based on a locally isothermal treatment. The computed velocity amplitude and the temperature-perturbation as functions of the wave period exhibit a sharp peak in the region between 180 and 300 s, thus showing the possibility of interpreting the five-minute oscillations as a resonant phenomenon. The propagating or stationary nature of the waves is investigated by a study of the phase of the proposed analytical solution.

GMO detection using a bioluminescent real time reporter (BART of loop mediated isothermal amplification (LAMP suitable for field use

Directory of Open Access Journals (Sweden)

Kiddle Guy

2012-04-01

Full Text Available Abstract Background There is an increasing need for quantitative technologies suitable for molecular detection in a variety of settings for applications including food traceability and monitoring of genetically modified (GM crops and their products through the food processing chain. Conventional molecular diagnostics utilising real-time polymerase chain reaction (RT-PCR and fluorescence-based determination of amplification require temperature cycling and relatively complex optics. In contrast, isothermal amplification coupled to a bioluminescent output produced in real-time (BART occurs at a constant temperature and only requires a simple light detection and integration device. Results Loop mediated isothermal amplification (LAMP shows robustness to sample-derived inhibitors. Here we show the applicability of coupled LAMP and BART reactions (LAMP-BART for determination of genetically modified (GM maize target DNA at low levels of contamination (0.1-5.0% GM using certified reference material, and compare this to RT-PCR. Results show that conventional DNA extraction methods developed for PCR may not be optimal for LAMP-BART quantification. Additionally, we demonstrate that LAMP is more tolerant to plant sample-derived inhibitors, and show this can be exploited to develop rapid extraction techniques suitable for simple field-based qualitative tests for GM status determination. We also assess the effect of total DNA assay load on LAMP-BART quantitation. Conclusions LAMP-BART is an effective and sensitive technique for GM detection with significant potential for quantification even at low levels of contamination and in samples derived from crops such as maize with a large genome size. The resilience of LAMP-BART to acidic polysaccharides makes it well suited to rapid sample preparation techniques and hence to both high throughput laboratory settings and to portable GM detection applications. The impact of the plant sample matrix and genome loading

Pre-eruptive magmatic processes re-timed using a non-isothermal approach to magma chamber dynamics.

Science.gov (United States)

Petrone, Chiara Maria; Bugatti, Giuseppe; Braschi, Eleonora; Tommasini, Simone

2016-10-05

Constraining the timescales of pre-eruptive magmatic processes in active volcanic systems is paramount to understand magma chamber dynamics and the triggers for volcanic eruptions. Temporal information of magmatic processes is locked within the chemical zoning profiles of crystals but can be accessed by means of elemental diffusion chronometry. Mineral compositional zoning testifies to the occurrence of substantial temperature differences within magma chambers, which often bias the estimated timescales in the case of multi-stage zoned minerals. Here we propose a new Non-Isothermal Diffusion Incremental Step model to take into account the non-isothermal nature of pre-eruptive processes, deconstructing the main core-rim diffusion profiles of multi-zoned crystals into different isothermal steps. The Non-Isothermal Diffusion Incremental Step model represents a significant improvement in the reconstruction of crystal lifetime histories. Unravelling stepwise timescales at contrasting temperatures provides a novel approach to constraining pre-eruptive magmatic processes and greatly increases our understanding of magma chamber dynamics.

Resistivity behavior in isothermal annealing of Pd-H(D) alloys around 50 K

International Nuclear Information System (INIS)

Yamakawa, Kohji; Maeta, Hiroshi

2004-01-01

The behavior of electrical resistivity during hydrogen (deuterium) ordering is investigated for Pd-H(D) alloys of various hydrogen concentrations around 50 K. The disordered hydrogen (deuterium) atoms are introduced by quenching from 100 K into liquid helium immediately before isothermal annealings. The disordered atoms order by migration of the atoms during the heating-up of the specimens. On the isothermal curves of the resistivity in the high temperature range, the resistivity increases at first and then adopts a constant value dependent on the annealing temperature. On the other hand, the resistivity increases and then decreases during isothermal annealing in the low temperature range, nevertheless the ordering is progressing. The annealing time, at which the resistivity maximum appears, and the resistivity value of the maximum increase with decreasing annealing temperature. Furthermore, the decreasing resistivity after the maximum saturates to a value dependent on each annealing temperature. Therefore, it becomes clear that an equilibrium amount of ordering depends on the temperature and the resistivity increases in the early stage of hydrogen (deuterium) ordering and decreases in the later stage. The resistivity maximum in the isothermal annealing curve is caused by the nucleation and growth of ordered domains of hydrogen (deuterium) atoms

Thermodynamic analysis of water vapor sorption isotherms and mechanical properties of selected paper-based food packaging materials.

Science.gov (United States)

Rhim, Jong-Whan; Lee, Jun Ho

2009-01-01

Adsorption isotherms of 3 selected paper-based packaging materials, that is, vegetable parchment (VP) paper, Kraft paper, and solid-bleached-sulfate (SBS) paperboard, were determined at 3 different temperatures (25, 40, and 50 degrees C). The GAB isotherm model was found to fit adequately for describing experimental adsorption isotherm data for the paper samples. The monolayer moisture content of the paper samples decreased with increase in temperature, which is in the range of 0.0345 to 0.0246, 0.0301 to 0.0238, and 0.0318 to 0.0243 g water/g solid for the MG paper, the Kraft paper, and the SBS paperboard, respectively. The net isosteric heats of sorption (q(st)) for the paper samples decreased exponentially with increase in moisture content after reaching the maximum values of 18.51, 27.39, and 26.80 kJ/mol for the VP paper, the Kraft paper, and the SBS paperboard, respectively, at low-moisture content. The differential enthalpy and entropy of 3 paper samples showed compensation phenomenon with the isokinetic temperature of 399.7 K indicating that water vapor had been adsorbed onto the paper samples with the same mechanism. Depending on the paper material, tensile strength of paper samples was affected by moisture content.

Integration and global analysis of isothermal titration calorimetry data for studying macromolecular interactions.

Science.gov (United States)

Brautigam, Chad A; Zhao, Huaying; Vargas, Carolyn; Keller, Sandro; Schuck, Peter

2016-05-01

Isothermal titration calorimetry (ITC) is a powerful and widely used method to measure the energetics of macromolecular interactions by recording a thermogram of differential heating power during a titration. However, traditional ITC analysis is limited by stochastic thermogram noise and by the limited information content of a single titration experiment. Here we present a protocol for bias-free thermogram integration based on automated shape analysis of the injection peaks, followed by combination of isotherms from different calorimetric titration experiments into a global analysis, statistical analysis of binding parameters and graphical presentation of the results. This is performed using the integrated public-domain software packages NITPIC, SEDPHAT and GUSSI. The recently developed low-noise thermogram integration approach and global analysis allow for more precise parameter estimates and more reliable quantification of multisite and multicomponent cooperative and competitive interactions. Titration experiments typically take 1-2.5 h each, and global analysis usually takes 10-20 min.

Review of low-temperature vapour power cycle engines with quasi-isothermal expansion

OpenAIRE

Igobo, Opubo N.; Davies, Philip A.

2014-01-01

External combustion heat cycle engines convert thermal energy into useful work. Thermal energy resources include solar, geothermal, bioenergy, and waste heat. To harness these and maximize work output, there has been a renaissance of interest in the investigation of vapour power cycles for quasi-isothermal (near constant temperature) instead of adiabatic expansion. Quasi-isothermal expansion has the advantage of bringing the cycle efficiency closer to the ideal Carnot efficiency, but it requi...

Loop-mediated isothermal amplification for rapid and convenient detection of Mycoplasma hyopneumoniae.

Science.gov (United States)

Li, Jiahe; Minion, F Chris; Petersen, Andrew C; Jiang, Fei; Yang, Sheng; Guo, Panpan; Li, Jinxiang; Wu, Wenxue

2013-04-01

Loop-mediated isothermal amplification (LAMP), a novel method of gene amplification, was employed in this study for detecting Mycoplasma hyopneumoniae in the respiratory tract or lungs of swine. The pathogen can be detected in LAMP reactions containing as few as 10 fg purified target DNA (10 copies of M. hyopneumoniae genome) within 30 min, which was comparable to real-time PCR. After 30-min reaction at 63 °C, the addition of a certain amount of dye (SYBR Green I and hydroxyl naphthol blue at a proper ratio) into the LAMP reaction system makes the results easily determined as positive or negative by visual inspection. In addition, the LAMP was able to distinguish between M. hyopneumoniae and other closely-related mycoplasma strains, indicating a high degree of specificity. The LAMP assay was more simple and cheap, since the reaction could be completed under isothermal conditions and less laboratorial infrastructure are required. And, it was proven reliable for M. hyopneumoniae diagnosis of nasal swab and lung samples from the field.

Maps of Fe-Al phases formation kinetics parameters during isothermal sintering

Energy Technology Data Exchange (ETDEWEB)

Pochec, Ewelina, E-mail: epochec@wat.edu.pl [Department of Advanced Materials and Technology, Military University of Technology (Poland); Jozwiak, Stanislaw; Karczewski, Krzysztof; Bojar, Zbigniew [Department of Advanced Materials and Technology, Military University of Technology (Poland)

2012-10-10

Highlights: Black-Right-Pointing-Pointer The sintering temperature and compaction pressure have a strong influence on the sinters structure. Black-Right-Pointing-Pointer The measurements confirmed the presence of the high-aluminium phases from Fe-Al equilibrium system in tested sinters. Black-Right-Pointing-Pointer The kinetics of Fe-Al phase formation can be described by Johnson-Mehl-Avrami modelling. - Abstract: The influence of technological parameters (compaction pressure and sintering temperature) on Fe-Al phase formation was investigated. The kinetics of phase transformation preceding and during an SHS reaction was studied in isothermal conditions by DSC using the JMA (Johnson-Mehl-Avrami) model. This model allowed us to determine basic kinetic parameters, including the Avrami exponent, which characterises the rate and manner of particular phase nucleation. The activation energy (E{sub a}) of particular phase formation was determined by the Kissinger method. XRD analysis and SEM observations of sintered material showed that not only Fe{sub 2}Al{sub 5} phase and low-aluminium solid solution in iron but also aluminium-rich FeAl{sub 2} and FeAl{sub 3} phases are formed during the sintering of an FeAl50 elementary powder mixture in isothermal conditions with an SHS reaction. The above conclusions were confirmed by iron-based solid solution lattice parameter studies and microhardness measurements.

Decreasing Ni, Cu, Cd, and Zn heavy metal magnetite-bentonite nanocomposites and adsorption isotherm study

Science.gov (United States)

Eskandari, M.; Zakeri Khatir, M.; Khodadadi Darban, A.; Meshkini, M.

2018-04-01

This present study was conducted to investigate the effect of magnetite-bentonite nanocomposite on heavy metal removal from an effluent. For this purpose, magnetite-bentonite nanocomposite was prepared through the chemical method and characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, followed by studying the effect of produced nanocomposite on the removal of Ni2+, Cu2+, Cd2+, and Zn2+ heavy metal ions. The results showed that adsorption capacity of magnetite-bentonite nanocomposites for the studied ions is in the order of Zn2+ > Cd2+ > Cu2+ > Ni2+. Adsorption isotherms were drawn for Ni2+, Cu2+, Cd2+, and Zn2+ cations and found that cations adsorption on nanocomposite fit into Langmuir model.

The Cr–Fe–Nb ternary system: Experimental isothermal sections at 700 °C, 1050 °C and 1350 °C

Energy Technology Data Exchange (ETDEWEB)

Jacob, Aurélie, E-mail: a.jacob@fz-juelich.de [Forschungszentrum Juelich, IEK-2, 52425 Juelich (Germany); Schmetterer, Clemens [Forschungszentrum Juelich, IEK-2, 52425 Juelich (Germany); Fraunhofer-UMSICHT, 92237 Sulzbach-Rosenberg (Germany); Grüner, Daniel; Wessel, Egbert [Forschungszentrum Juelich, IEK-2, 52425 Juelich (Germany); Hallstedt, Bengt [Institute for Materials Applications in Mechanical Engineering, RWTH Aachen University, Augustinerbach 4, 52062 Aachen (Germany); Singheiser, Lorenz [Forschungszentrum Juelich, IEK-2, 52425 Juelich (Germany)

2015-11-05

The Cr–Fe–Nb system is an important constituent system in the development of Laves-phase reinforced steels. It contains two Laves-phase polytypes, i.e. C14–Fe{sub 2}Nb and C15–Cr{sub 2}Nb. While the first forms a substantial ternary solid solution with Cr, the latter only shows a limited solubility for Fe. The phase equilibria in the Cr–Fe–Nb system are shown in three isothermal sections at 700, 1050 and 1350 °C. Scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX), X-ray diffraction (XRD) and electron back scatter diffraction (EBSD) were used to determine the phase equilibria from which the isothermal sections were constructed. - Highlights: • Determination of Phase Equilibria in the Cr–Fe–Nb system at 700, 1050 and 1350 °C. • Isothermal sections at 700, 1050 and 1350 °C were established. • Homogeneity range of Laves phases were determined. • Solubility of Fe and Cr and lattice parameter evolution in the ternary phases were determined.

Estimating Uranium Partition Coefficients from Laboratory Adsorption Isotherms

International Nuclear Information System (INIS)

Hull, L.C.; Grossman, C.; Fjeld, R.A.; Coates, J.T.; Elzerman, A.W.

2002-01-01

An estimated 330 metric tons of uranium have been buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of uranium transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of uranium fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms have been measured in the laboratory and fit with a Freundlich isotherm. The Freundlich n parameter was statistically identical for 14 sediment samples. The Freundlich Kf for seven samples, where material properties have been measured, is correlated to sediment surface area. Based on these empirical observations, a model has been derived for adsorption of uranium on INEEL sedimentary materials using surface complexation theory. The model was then used to predict the range of adsorption conditions to be expected at the SDA. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth

Characterization of rain heights due to 0° isotherm in tropical and subtropical climates: implication on rain-induced attenuation prediction

Science.gov (United States)

Ojo, J. S.; Owolawi, P. A.

2018-01-01

In this paper, the dynamics of the structure of the rain profile as related to the zero-degree isotherm height and the implications for attenuation prediction along the Earth-space propagation links at locations in Nigeria, a tropical region, and South Africa, a subtropical region, are presented. Five-year (January 2010-December 2014) precipitation data on board the Tropical Rainfall Measuring Mission (TRMM) satellite have been analyzed over some selected locations in the two regions. The influences of the zero-degree isotherm height on some observed weather parameters are also discussed. The result on the influence of air temperature on rain height h r shows a significant increase in the tropical environment as compared with those in the subtropics. However, when h r results are compared with those obtained using rain height as recommended by the International Telecommunication Union (ITU), there is a significant difference at the 0.01% unavailability of the signal in a year particularly at higher frequencies. Further comparison with the slant path attenuation at 0.01% unavailability of the signal in a year shows a slight deviation (between 1.04 and 2.13 dB) in rain height than those acquired using the measured rain height in the tropical locations. Nevertheless, the result is slightly less than those obtained using the measured rain height in the subtropical locations with the differences in dB between - 0.49 and - 1.18. The overall results will be useful for estimating the link budgeting for digital radio satellite broadcasting. It will also be applicable for radar propagation systems at higher-frequency bands in Nigeria and South Africa.

Determination and modeling of desorption isotherms of Maria biscuits from different brands

OpenAIRE

Pereira, DFC; Correia, PMR; Guiné, Raquel

2012-01-01

Biscuits (sweet, strongly sweet, semi-sweet biscuits, crackers, wafers) are characterized by a low moisture content in the final product and high levels of fat and sugar [1]. Dehydrated foods, such as biscuits, are very sensitive to gain moisture from the surrounding atmosphere, resulting in a consequent deterioration. When, at constant temperature, the product's moisture increases from the atmosphere, is obtained the adsorption isotherm and when it loses moisture is obtained the desorption i...

Depth to the bottom of magnetic layer in South America and its relationship to Curie isotherm, Moho depth and seismicity behavior

Directory of Open Access Journals (Sweden)

Javier Idárraga-García

2018-01-01

After comparing our results with the Moho depths reported by other authors, we have found that the Curie isotherm is deeper than Moho in most of the South American Platform (northward to ∼20°S, which is located in the stable cratonic area at the east of the Andes. This is evidence that the lithospheric mantle here is magnetic and contributes to the long wavelength magnetic signal. Also, our results support the hypothesis that the Curie isotherm may be acting as a boundary above which most of the crustal seismicity is concentrated. Below this boundary the occurrence of seismic events decreases dramatically.

Multiple stable isotope fronts during non-isothermal fluid flow

Science.gov (United States)

Fekete, Szandra; Weis, Philipp; Scott, Samuel; Driesner, Thomas

2018-02-01

develop in kinetically limited systems, which propagates with the advection speed of the incoming fluid and is, therefore, traveling fastest. The results show that oxygen isotope signatures at thermal fronts recorded in rocks and veins that experienced isotope exchange with fluids can easily be misinterpreted, namely if bulk analytical techniques are applied. However, stable isotope microanalysis on precipitated minerals may - if later isotope exchange is kinetically limited - provide a valuable archive of the transient thermal and hydrological evolution of a system.

Influence of pre-treatments on the desorption isotherm ...

African Journals Online (AJOL)

Influence of pre-treatments on the desorption isotherm characteristics of plaintain. P-N T Johnson. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/gjs.v39i1.15851 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

Loop-mediated isothermal amplification (LAMP) based detection of ...

African Journals Online (AJOL)

SAM

2014-05-07

May 7, 2014 ... 2 months for growing in a culture. Therefore, to control .... The LAMP reaction is carried out in a 25 µL reaction mixture containing ..... J. Fish Dis. 32(6):491-497. Goto M, Honda E, Ogura A, Nomoto A, Hanaki K (2009). Colorimetric detection of loop-mediated isothermal amplification reaction by using hydroxy ...

Isothermal Stability and Selected Mechanical Properties of Zr48Cu36Al8Ag8 Bulk Metallic Glass

Directory of Open Access Journals (Sweden)

Błyskun P.

2017-09-01

Full Text Available The aim of this work was to investigate the influence of isothermal annealing on the amorphous structure stability of the Zr48Cu36Al8Ag8 alloy. A series of continuous heating examinations was performed on the differential scanning calorimeter in order to determine the temperature limits for isothermal annealing series where the time to crystallization was measured. The obtained results were calculated and a time-temperature-transformation diagram was created and discussed. Static compression test as well as microhardness measurements of the as-quenched samples gave a mechanical properties results supplement. The measured properties (σc = 1800 MPa and 614 HV0.05 are comparable to the literature results for this alloy. Fractographic observations with the scanning electron microscope were also performed in order to prove some plasticity observed during the strength tests.

Application of a new method for data analysis of isothermal titration calorimetry in the interaction between human serum albumin and Ni{sup 2+}[Serum albumin; Nickel; Isothermal titration calorimetry; Calorimetric method

Energy Technology Data Exchange (ETDEWEB)

Saboury, Ali Akbar. E-mail: saboury@chamran.ut.ac.ir

2003-12-01

The interaction of human serum albumin (HAS) with divalent nickel ion was studied by isothermal titration calorimetry (ITC) in 30 mM Tris buffer, pH 7.0. There is a set of eight identical and independent binding sites for nickel ions on the protein at the temperature of 300 K. A new calorimetric data analysis allows the determination of the complete set of thermodynamic parameters. The binding isotherm for nickel-HSA interaction is easily obtained by carrying out two different ITC experiments. In the first experiment, the enthalpy of binding for one mole of nickel ion to one mole of binding site on HSA ({delta}H=-36.5 kJ) is obtained, and is used in a second experiment to determine the binding isotherm and to find the number of binding sites (g=8) and the equilibrium constant (K=0.57 {mu}M{sup -1})

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds

Energy Technology Data Exchange (ETDEWEB)

Ramos-Ramirez, Esthela, E-mail: ramosre@quijote.ugto.mx [Centro de Investigaciones en Quimica Inorganica de la Universidad de Guanajuato, Noria Alta s/n, Col. Noria Alta, C.P. 36050, Guanajuato, Gto. (Mexico); Gutierrez Ortega, Norma L.; Conteras Soto, Cesar A. [Centro de Investigaciones en Quimica Inorganica de la Universidad de Guanajuato, Noria Alta s/n, Col. Noria Alta, C.P. 36050, Guanajuato, Gto. (Mexico); Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, km 36.5, La Marquesa, Coyoacan Mexico, C.P. 52750 (Mexico); Olguin Gutierrez, Maria T. [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, km 36.5, La Marquesa, Coyoacan Mexico, C.P. 52750 (Mexico)

2009-12-30

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio = 2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N{sub 2} adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds

International Nuclear Information System (INIS)

Ramos-Ramirez, Esthela; Gutierrez Ortega, Norma L.; Conteras Soto, Cesar A.; Olguin Gutierrez, Maria T.

2009-01-01

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio = 2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N 2 adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds.

Science.gov (United States)

Ramos-Ramírez, Esthela; Ortega, Norma L Gutiérrez; Soto, Cesar A Contreras; Gutiérrez, Maria T Olguín

2009-12-30

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio=2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N(2) adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

Isothermal deformation of gamma titanium aluminide

International Nuclear Information System (INIS)

Srinivasan, R.; Singh, J.P.; Tuval, E.; Weiss, I.

1996-01-01

Gamma titanium aluminide has received considerable attention in recent years from the automotive industry as a potential material for making rotating and reciprocating components to produce a quieter and more efficient engine. The objectives of this study were to identify processing routes for the manufacture of automobile valves from gamma titanium aluminide. The issues considered were microstructure and composition of the material, and processing parameters such as deformation rates, temperatures, and total deformation. This paper examines isothermal deformation of gamma titanium aluminide in order to develop a processing window for this type of material

Adsorptive Removal of Reactive Black 5 from Wastewater Using Bentonite Clay: Isotherms, Kinetics and Thermodynamics

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Muhammad Tahir Amin

2015-11-01

Full Text Available The studies of the kinetics and isotherms adsorption of the Reactive Black 5 (RB5 onto bentonite clay were explored in a batch study in a laboratory. The maximum RB5 adsorption conditions of bentonite clay were optimized such as shaking speed (100 rpm, temperature (323 K, pH (10, contact time (40 min, initial dye concentration (170 mg·L−1, and particle size (177 µm. The adsorbent surface was characterized using Fourier Transform Infrared Spectroscopy spectroscopy. The mechanisms and characteristic parameters of the adsorption process were analyzed using two parameter isotherm models which revealed the following order (based on the coefficient of determination: Harkin-Jura (0.9989 > Freundlich (0.9986 and Halsey (0.9986 > Langmuir (0.9915 > Temkin (0.9818 > Dubinin–Radushkevich (0.9678. This result suggests the heterogeneous nature of bentonite clay. Moreover, the adsorption process was chemisorption in nature because it follows the pseudo-second order reaction model with R2 value of 0.9998, 0.9933 and 0.9891 at 25, 75 and 100 mg·L−1 RB5 dye in the solution, respectively. Moreover, based on the values of standard enthalpy, Gibbs free energy change, and entropy, bentonite clay showed dual nature of exothermic and endothermic, spontaneous and non-spontaneous as well as increased and decreased randomness at solid–liquid interface at 303–313 K and 313–323 K temperature, respectively.

Tuberculosis Biomarker Extraction and Isothermal Amplification in an Integrated Diagnostic Device.

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Amy Creecy

Full Text Available In this study, we integrated magnetic bead-based sample preparation and isothermal loop mediated amplification (LAMP of TB in a single tube. Surrogate sputum samples produced by the Program for Appropriate Technology in Health containing inactivated TB bacteria were used to test the diagnostic. In order to test the sample preparation method, samples were lysed, and DNA was manually extracted and eluted into water in the tube. In a thermal cycler, LAMP amplified TB DNA from 103 TB cells/mL of sputum at 53.5 ± 3.3 minutes, 104 cells/mL at 46.3 ± 2.2 minutes, and 105 cells/mL at 41.6 ± 1.9 minutes. Negative control samples did not amplify. Next, sample preparation was combined with in-tubing isothermal LAMP amplification by replacing the water elution chamber with a LAMP reaction chamber. In this intermediate configuration, LAMP amplified 103 cells/mL at 74 ± 10 minutes, 104 cells/mL at 60 ± 9 minutes, and 105 TB cells/mL of sputum at 54 ± 9 minutes. Two of three negative controls did not amplify; one amplified at 100 minutes. In the semi-automated system, DNA was eluted directly into an isothermal reaction solution containing the faster OptiGene DNA polymerase. The low surrogate sputum concentration, 103 TB cells/mL, amplified at 52.8 ± 3.3 minutes, 104 cells/mL at 45.4 ± 11.3 minutes, and 105 cells/mL at 31.8 ± 2.9 minutes. TB negative samples amplified at 66.4 ± 7.4 minutes. This study demonstrated the feasibility of a single tube design for integrating sample preparation and isothermal amplification, which with further development could be useful for point-of-care applications, particularly in a low-resource setting.

Isothermal Time-Temperature-Precipitation Diagram for an Aluminum Alloy 6005A by In Situ DSC Experiments

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Benjamin Milkereit

2014-03-01

Full Text Available Time-temperature-precipitation (TTP diagrams deliver important material data, such as temperature and time ranges critical for precipitation during the quenching step of the age hardening procedure. Although the quenching step is continuous, isothermal TTP diagrams are often applied. Together with a so-called Quench Factor Analysis, they can be used to describe very different cooling paths. Typically, these diagrams are constructed based on mechanical properties or microstructures after an interrupted quenching, i.e., ex situ analyses. In recent years, an in situ calorimetric method to record continuous cooling precipitation diagrams of aluminum alloys has been developed to the application level by our group. This method has now been transferred to isothermal experiments, in which the whole heat treatment cycle was performed in a differential scanning calorimeter. The Al-Mg-Si-wrought alloy 6005A was investigated. Solution annealing at 540 °C and overcritical quenching to several temperatures between 450 °C and 250 °C were followed by isothermal soaking. Based on the heat flow curves during isothermal soaking, TTP diagrams were determined. An appropriate evaluation method has been developed. It was found that three different precipitation reactions in characteristic temperature intervals exist. Some of the low temperature reactions are not accessible in continuous cooling experiments and require isothermal studies.

Moisture sorption isotherms of dehydrated whey proteins

OpenAIRE

Suzana Rimac Brnčić; Vesna Lelas; Zoran Herceg; Marija Badanjak

2010-01-01

Moisture sorption isotherms describe the relation between the moisture content of the dry material (food) and relative humidity of the surrounding environment. The data obtained are important in modelling of drying process conditions, packaging and shelf-life stability of food that will provide maximum retaining of aroma, colour and texture as well as nutritive and biological value. The objective of this research was to establish the equilibrium moisture content and water activity, as well as...

Gas-phase formaldehyde adsorption isotherm studies on activated carbon: correlations of adsorption capacity to surface functional group density.

Science.gov (United States)

Carter, Ellison M; Katz, Lynn E; Speitel, Gerald E; Ramirez, David

2011-08-01

Formaldehyde (HCHO) adsorption isotherms were developed for the first time on three activated carbons representing one activated carbon fiber (ACF) cloth, one all-purpose granular activated carbon (GAC), and one GAC commercially promoted for gas-phase HCHO removal. The three activated carbons were evaluated for HCHO removal in the low-ppm(v) range and for water vapor adsorption from relative pressures of 0.1-0.9 at 26 °C where, according to the IUPAC isotherm classification system, the adsorption isotherms observed exhibited Type V behavior. A Type V adsorption isotherm model recently proposed by Qi and LeVan (Q-L) was selected to model the observed adsorption behavior because it reduces to a finite, nonzero limit at low partial pressures and it describes the entire range of adsorption considered in this study. The Q-L model was applied to a polar organic adsorbate to fit HCHO adsorption isotherms for the three activated carbons. The physical and chemical characteristics of the activated carbon surfaces were characterized using nitrogen adsorption isotherms, X-ray photoelectron spectroscopy (XPS), and Boehm titrations. At low concentrations, HCHO adsorption capacity was most strongly related to the density of basic surface functional groups (SFGs), while water vapor adsorption was most strongly influenced by the density of acidic SFGs.

Isothermal reaction calorimetry as a tool for kinetic analysis

International Nuclear Information System (INIS)

Zogg, Andreas; Stoessel, Francis; Fischer, Ulrich; Hungerbuehler, Konrad

2004-01-01

Reaction calorimetry has found widespread application for thermal and kinetic analysis of chemical reactions in the context of thermal process safety as well as process development. This paper reviews the most important reaction calorimetric principles (heat-flow, heat-balance, power-compensation, and Peltier principle) and their applications in commercial or scientific devices. The discussion focuses on the different dynamic behavior of the main calorimetric principles during an isothermal reaction measurement. Examples of available reaction calorimeters are further compared considering their detection limit, time constant as well as temperature range. In a second part, different evaluation methods for the isothermally measured calorimetric data are reviewed and discussed. The methods will be compared, focusing especially on the fact that reaction calorimetric data always contains additional informations not directly related to the actual chemical reaction such as heat of mixing, heat of phase-transfer/change processes or simple measurement errors. Depending on the evaluation method applied such disturbances have a significant influence on the calculated reaction enthalpies or rate constants

Adsorption of hazardous cationic dye onto the combustion derived SrTiO3 nanoparticles: Kinetic and isotherm studies

Directory of Open Access Journals (Sweden)

N.P. Bhagya

2016-03-01

Full Text Available In this article we report on solution combustion method to synthesize SrTiO3 nanoparticles (ST-NPs and the removal of malachite green (MG azo dye from the aqueous solution. The synthesized ST-NPs were calcined at 600 °C for 2 h. Powder X-ray diffraction (PXRD, field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, and Brunauer–Emmett–Teller (BET were used to characterize the product. Adsorption experiments were performed with cationic malachite green (MG dye. ∼98% dye was adsorbed onto the ST-NPs at pH 10 for 30 min of the contact time. The optimum adsorbent dose was found to be 0.015 g/L of the dye. To study the adsorption kinetics Langmuir Hinshelwood model was used and the first order kinetic best describes the MG adsorption onto the ST-NPs. The adsorption isotherms data of MG onto ST-NPs obtained were analyzed by Langmuir and Freundlich isotherm models and the results describe the best representation of the Langmuir isotherm model.

The adsorption characteristics and porous structure of bentonite adsorbents as determined from the adsorption isotherms of benzene vapor

Directory of Open Access Journals (Sweden)

LEPA STOJANOVSKA

2004-02-01

Full Text Available The adsorption of benzene vapor on natural and acid activated bentonites was treated by the theory of volume filling of micropores. The micropore volume and characteristic values of the free energy of adsorption were determined from the adsorption isotherms. The Dubinin–Radushkevish–Stoeckli and Dubinin–Astakhov equations were used for this purpose. The results showed that natural bentonite has a more homogeneous micropore structure than the acid activated ones. The characteristic values of the free energy of adsorption for the natural bentonite were higher than those of the acid activated bentonite. This is due to differences in its structure and the pore size.

Isothermal-isobaric Nose-Hoover method application: correlation length and disclinations per particle

International Nuclear Information System (INIS)

Morales, J.J.; Nuevo, J.M.; Rull, L.F.

1987-01-01

The new isothermic-isobaric MD(T,p,N) method of Nose and Hoover is applied in Molecular Dynamics simulations to both liquid and solid near the phase transition. We tested for an appropriate value of the isobaric friction coefficient before calculating the correlation length in the liquid and the disclinations per particle in solid on a big system of 2304 particles. The results are compared with those obtained by traditional MD simulation (E,V,N). (author)

Morphology and crystallographic orientation relationship in isothermally transformed Fe–N austenite

International Nuclear Information System (INIS)

Jiao, Dongling; Luo, Chengping; Liu, Jiangwen; Zhang, Guoqing

2014-01-01

The 225 °C isothermal transformation of a high-nitrogen austenite with Fe–2.71 wt.% N was investigated by means of electron microscopy. It was found that the transformation products were composed of ultrafine α-Fe and γ′-Fe 4 N plus retained austenite γ, which were in two types of morphologies, namely, (i) with the retained austenite patches dispersed among the (α-Fe + γ′-Fe 4 N) packets and (ii) with the ultrafine α-Fe and γ/γ′-Fe 4 N laths interwoven with each other within a single bainitic packet. A cube–cube orientation relationship between the γ (austenite) and γ′-Fe 4 N, and a near Greninger–Troiano (G–T) one between the γ (austenite) and the bainitic α-ferrite were detected. The morphology, orientation relationship and high hardness (> 1000 HV) of the transformation products indicated that the isothermal transformation of the high nitrogen austenite was analogous to a bainitic one. - Highlights: • Isothermal transformation products consisted of nano-sized α-Fe + γ′ + γ (retained). • The hardness of transformation product exceeded 1000 HV. • The α-Fe and γ/γ′-Fe 4 N kept a near G-T OR in the grain interior

Dust ion acoustic solitary structures in the presence of isothermal positrons

Energy Technology Data Exchange (ETDEWEB)

Paul, A. [Jadavpur University, Department of Mathematics (India); Das, A. [B. N. S. U. P. School (India); Bandyopadhyay, A., E-mail: abandyopadhyay1965@gmail.com [Jadavpur University, Department of Mathematics (India)

2017-02-15

The Sagdeev potential technique has been employed to study the dust ion acoustic solitary waves and double layers in an unmagnetized collisionless dusty plasma consisting of negatively charged static dust grains, adiabatic warm ions, isothermally distributed electrons, and positrons. A computational scheme has been developed to draw the qualitatively different compositional parameter spaces or existence domains showing the nature of existence of different solitary structures with respect to any parameter of the present plasma system. The present system supports both positive and negative potential double layers. The negative potential double layer always restricts the occurrence of negative potential solitary waves, i.e., any sequence of negative potential solitary waves having monotonically increasing amplitude converges to a negative potential double layer. However, there exists a parameter regime for which the positive potential double layer is unable to restrict the occurrence of positive potential solitary waves. As a result, in this region of the parameter space, there exist solitary waves after the formation of positive potential double layer, i.e., positive potential supersolitons have been observed.

Instabilities of isothermal liquid films

International Nuclear Information System (INIS)

Solesio, J.N.

1977-04-01

The integral forms of the mass and linear momentum balances are given for a two-phase flow system with surface tension and without material surface properties. The instantaneous local laws for each phase and the jump conditions for the interface are derived from these balance laws. Then, these laws are systematically simplified by means of dimensional analysis for an isothermal liquid film flowing down a plane. The stability studies of films are critically reviewed. The different methods are divided into two groups: the first one deals with the global approach, the second one with the perturbation theory. This group includes a new technique based upon the method of quadrature by differentiation. Finally, the different methods are compared [fr

Isobaric expansion coefficient and isothermal compressibility for a finite-size ideal Fermi gas system

International Nuclear Information System (INIS)

Su, Guozhen; Chen, Liwei; Chen, Jincan

2014-01-01

Due to quantum size effects (QSEs), the isobaric thermal expansion coefficient and isothermal compressibility well defined for macroscopic systems are invalid for finite-size systems. The two parameters are redefined and calculated for a finite-size ideal Fermi gas confined in a rectangular container. It is found that the isobaric thermal expansion coefficient and isothermal compressibility are generally anisotropic, i.e., they are generally different in different directions. Moreover, it is found the thermal expansion coefficient may be negative in some directions under the condition that the pressures in all directions are kept constant. - Highlights: • Isobaric thermal expansion coefficient and isothermal compressibility are redefined. • The two parameters are calculated for a finite-size ideal Fermi gas. • The two parameters are generally anisotropic for a finite-size system. • Isobaric thermal expansion coefficient may be negative in some directions

Multiple strategies to improve sensitivity, speed and robustness of isothermal nucleic acid amplification for rapid pathogen detection

Directory of Open Access Journals (Sweden)

Lemieux Bertrand

2011-05-01

Full Text Available Abstract Background In the past decades the rapid growth of molecular diagnostics (based on either traditional PCR or isothermal amplification technologies meet the demand for fast and accurate testing. Although isothermal amplification technologies have the advantages of low cost requirements for instruments, the further improvement on sensitivity, speed and robustness is a prerequisite for the applications in rapid pathogen detection, especially at point-of-care diagnostics. Here, we describe and explore several strategies to improve one of the isothermal technologies, helicase-dependent amplification (HDA. Results Multiple strategies were approached to improve the overall performance of the isothermal amplification: the restriction endonuclease-mediated DNA helicase homing, macromolecular crowding agents, and the optimization of reaction enzyme mix. The effect of combing all strategies was compared with that of the individual strategy. With all of above methods, we are able to detect 50 copies of Neisseria gonorrhoeae DNA in just 20 minutes of amplification using a nearly instrument-free detection platform (BESt™ cassette. Conclusions The strategies addressed in this proof-of-concept study are independent of expensive equipments, and are not limited to particular primers, targets or detection format. However, they make a large difference in assay performance. Some of them can be adjusted and applied to other formats of nucleic acid amplification. Furthermore, the strategies to improve the in vitro assays by maximally simulating the nature conditions may be useful in the general field of developing molecular assays. A new fast molecular assay for Neisseria gonorrhoeae has also been developed which has great potential to be used at point-of-care diagnostics.

Extended forward sensitivity analysis of one-dimensional isothermal flow

International Nuclear Information System (INIS)

Johnson, M.; Zhao, H.

2013-01-01

Sensitivity analysis and uncertainty quantification is an important part of nuclear safety analysis. In this work, forward sensitivity analysis is used to compute solution sensitivities on 1-D fluid flow equations typical of those found in system level codes. Time step sensitivity analysis is included as a method for determining the accumulated error from time discretization. The ability to quantify numerical error arising from the time discretization is a unique and important feature of this method. By knowing the relative sensitivity of time step with other physical parameters, the simulation is allowed to run at optimized time steps without affecting the confidence of the physical parameter sensitivity results. The time step forward sensitivity analysis method can also replace the traditional time step convergence studies that are a key part of code verification with much less computational cost. One well-defined benchmark problem with manufactured solutions is utilized to verify the method; another test isothermal flow problem is used to demonstrate the extended forward sensitivity analysis process. Through these sample problems, the paper shows the feasibility and potential of using the forward sensitivity analysis method to quantify uncertainty in input parameters and time step size for a 1-D system-level thermal-hydraulic safety code. (authors)

Proximity hybridization-mediated isothermal exponential amplification for ultrasensitive electrochemical protein detection

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Yu Y

2017-08-01

Full Text Available Yanyan Yu, Gaoxing Su, Hongyan Zhu, Qing Zhu, Yong Chen, Bohui Xu, Yuqin Li, Wei Zhang School of Pharmacy, Nantong University, Nantong, People’s Republic of China Abstract: In this study, we fabricated a novel electrochemical biosensing platform on the basis of target-triggered proximity hybridization-mediated isothermal exponential amplification reaction (EXPAR for ultrasensitive protein analysis. Through rational design, the aptamers for protein recognition were integrated within two DNA probes. Via proximity hybridization principle, the affinity protein-binding event was converted into DNA assembly process. The recognition of protein by aptamers can trigger the strand displacement through the increase of the local concentrations of the involved probes. As a consequence, the output DNA was displaced, which can hybridize with the duplex probes immobilized on the electrode surface subsequently, leading to the initiation of the EXPAR as well as the cleavage of duplex probes. Each cleavage will release the gold nanoparticles (AuNPs binding sequence. With the modification of G-quadruplex sequence, electrochemical signals were yielded by the AuNPs through oxidizing 3,3',5,5'-tetramethylbenzidine in the presence of H2O2. The study we proposed exhibited high sensitivity toward platelet-derived growth factor BB (PDGF-BB with the detection limit of 52 fM. And, this method also showed great selectivity among the PDGF isoforms and performed well in spiked human serum samples. Keywords: electrochemical biosensor, proximity hybridization, PDGF-BB, isothermal exponential amplification, G-quadruplex 

THE CORONAL LOOP INVENTORY PROJECT: EXPANDED ANALYSIS AND RESULTS

Energy Technology Data Exchange (ETDEWEB)

Schmelz, J. T. [USRA, 7178 Columbia Gateway Drive, Columbia, MD 21046 (United States); Christian, G. M.; Chastain, R. A., E-mail: jschmelz@usra.edu [Physics Department, University of Memphis, Memphis, TN 38152 (United States)

2016-11-10

We have expanded upon earlier work that investigates the relative importance of coronal loops with isothermal versus multithermal cross-field temperature distributions. These results are important for determining if loops have substructure in the form of unresolved magnetic strands. We have increased the number of loops targeted for temperature analysis from 19 to 207 with the addition of 188 new loops from multiple regions. We selected all loop segments visible in the 171 Å images of the Atmospheric Imaging Assembly (AIA) that had a clean background. Eighty-six of the new loops were rejected because they could not be reliably separated from the background in other AIA filters. Sixty-one loops required multithermal models to reproduce the observations. Twenty-eight loops were effectively isothermal, that is, the plasma emission to which AIA is sensitive could not be distinguished from isothermal emission, within uncertainties. Ten loops were isothermal. Also, part of our inventory was one small flaring loop, one very cool loop whose temperature distribution could not be constrained by the AIA data, and one loop with inconclusive results. Our survey can confirm an unexpected result from the pilot study: we found no isothermal loop segments where we could properly use the 171-to-193 ratio method, which would be similar to the analysis done for many loops observed with TRACE and EIT. We recommend caution to observers who assume the loop plasma is isothermal, and hope that these results will influence the direction of coronal heating models and the effort modelers spend on various heating scenarios.

The adsorption of benzene from the gas phase on H-mordenite 1. A new model isotherm for adsorption on zeolites

Energy Technology Data Exchange (ETDEWEB)

Drachsel, W; Becker, K A

1977-10-01

This model was derived from considerations of the heterogeneous energy distribution of zeolite surfaces. A homogeneity parameter (m) was introduced. The isotherms approach a constant value at high pressure, and at low pressure they approach the Freundlich isotherm for m < 1 and the Henry isotherm at m > 1. Graphs and 19 references.

Comparison of reynolds averaged navier stokes based simulation and large eddy simulation for one isothermal swirling flow

DEFF Research Database (Denmark)

Yang, Yang; Kær, Søren Knudsen

2012-01-01

The flow structure of one isothermal swirling case in the Sydney swirl flame database was studied using two numerical methods. Results from the Reynolds-averaged Navier-Stokes (RANS) approach and large eddy simulation (LES) were compared with experimental measurements. The simulations were applied...

Thermistor based, low velocity isothermal, air flow sensor

International Nuclear Information System (INIS)

Cabrita, Admésio A C M; Mendes, Ricardo; Quintela, Divo A

2016-01-01

The semiconductor thermistor technology is applied as a flow sensor to measure low isothermal air velocities (<2 ms −1 ). The sensor is subjected to heating and cooling cycles controlled by a multifunctional timer. In the heating stage, the alternating current of a main AC power supply source guarantees a uniform thermistor temperature distribution. The conditioning circuit assures an adequate increase of the sensors temperature and avoids the thermal disturbance of the flow. The power supply interruption reduces the consumption from the source and extends the sensors life time. In the cooling stage, the resistance variation of the flow sensor is recorded by the measuring chain. The resistive sensor parameters proposed vary significantly and feature a high sensitivity to the flow velocity. With the aid of a computer, the data transfer, storage and analysis provides a great advantage over the traditional local anemometer readings. The data acquisition chain has a good repeatability and low standard uncertainties. The proposed method measures isothermal air mean velocities from 0.1 ms −1 to 2 ms −1 with a standard uncertainty error less than 4%. (paper)

Isothermal vapour–liquid equilibrium of binary systems containing polyoxyethylene dodecanoate and alcohols

International Nuclear Information System (INIS)

Khoiroh, Ianatul; Lee, Ming-Jer

2013-01-01

Highlights: ► An autoclave apparatus was used to measure binary vapor-liquid equilibrium data. ► The studied systems are polyoxyethylene dodecanoate with 2-butanol, tert-butanol, and 1-pentanol. ► The saturated pressure data were fitted accurately to the Antoine equation. ► The UNIQUAC, the NRTL, and the Flory–Huggins models correlated well the phase equilibrium data. ► The solvent activities have been calculated. - Abstract: Isothermal vapour–liquid equilibrium (VLE) data have been measured with a static method for three binary systems of polyoxyethylene dodecanoate {(POEDDA) + butan-2-ol} at T = (333.4 to 424.5) K, (POEDDA + tert-butanol) at (321.1 to 401.5) K, and (POEDDA + pentan-1-ol) at (340.2 to 419.4) K. Four feed compositions were studied over the concentration range of 0.099 to 0.432 of POEDDA mole fractions. The experimental results were fitted to the Antoine equation to regress the Antoine constants. These VLE data were further treated by using the Barker method to obtain the best fit of binary interaction parameters from the UNIQUAC, the NRTL, and the Flory–Huggins models. The results showed good agreement between the experimental and calculated values. The Flory–Huggins model yielded the best result with an overall average absolute relative deviation (AARD) of 2.1%. The solvent activities were also calculated and showed agree well with the calculated values from those three activity coefficient models.

A design method to isothermalize the core of high-temperature gas-cooled reactors

International Nuclear Information System (INIS)

Takano, M.; Sawa, K.

1987-01-01

A practical design method is developed to isothermalize the core of block-type high-temperature gas-cooled reactors (HTGRs). Isothermalization plays an important role in increasing the design margin on fuel temperature. In this method, the fuel enrichment and the size and boron content of the burnable poison rod are determined over the core blockwise so that the axially exponential and radially flat power distribution are kept from the beginning to the end of core life. The method enables conventional HTGRs to raise the outlet gas temperature without increasing the maximum fuel temperature

Monolayer and multilayer adsorption isotherm models for sorption from aqueous media

Energy Technology Data Exchange (ETDEWEB)

Saadi, Reyhaneh; Saadi, Zahra; Fazaeli, Reza; Fard, Narges Elmi [Islamic Azad University, Tehran (Iran, Islamic Republic of)

2015-05-15

Industrial wastewater polluted with various contaminants, including heavy metals, dyes, etc., endangers human health and the environment. Various separation techniques have been developed for the removal of pollutants from aqueous solutions. Adsorption process has drawn considerable attention due to its simplicity of design, high removal efficiency, even at dilute concentration, and economical aspect. We reviewed the most common two, three, four, and five parameter adsorption isotherm models corresponding to monolayer and multilayer adsorption on the basis of parameters that can be used for exploring novel adsorbents. Thermodynamic assumptions of the models give information about the surface properties, capacity of the adsorbent and adsorption mechanism. Seven error functions were investigated to evaluate the fitness quality of isotherm models with the experimental equilibrium data.

Development of Loop-Mediated Isothermal Amplification Assay for Detection of Entamoeba histolytica▿

Science.gov (United States)

Liang, Shih-Yu; Chan, Yun-Hsien; Hsia, Kan-Tai; Lee, Jing-Lun; Kuo, Ming-Chu; Hwa, Kuo-Yuan; Chan, Chi-Wen; Chiang, Ting-Yi; Chen, Jung-Sheng; Wu, Fang-Tzy; Ji, Dar-Der

2009-01-01

A novel one-step, closed-tube, loop-mediated isothermal amplification (LAMP) assay for detecting Entamoeba histolytica, one of the leading causes of morbidity in developing countries, was developed. The sensitivity of the LAMP assay is 1 parasite per reaction. A total of 130 clinical samples were analyzed, and the results compared with those of conventional nested PCR to validate the practicability of this assay. No DNA was amplified from other diarrheal pathogens, such as other Entamoeba species, bacteria, and viruses. These results indicate that LAMP is a rapid, simple, and valuable diagnostic tool for epidemiological studies of amebiasis. PMID:19321720

Isothermal calorimetry of enzymatic biodiesel reaction

DEFF Research Database (Denmark)

Fjerbæk Søtoft, Lene; Westh, Peter; Christensen, Knud Villy

2010-01-01

  Isothermal calorimetry ITC has been used to investigate enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by the immobilized lipase Novozym 435 at 40°C. The ITC-experiments clearly demonstrate the possibilities of investigating complex...... and composition change in the system, the heat of reaction at 40°C for the two systems has been determined to -9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and - 9.3 ± 0.7 kJ/mole when rapeseed oil and ethanol is used....

Estimation of the isothermal compressibility from event-by-event multiplicity fluctuation studies

Directory of Open Access Journals (Sweden)

Mukherjee Maitreyee

2018-01-01

Full Text Available The first estimation of the isothermal compressibility (kT of matter is presented for a wide range of collision energies from √sNN = 7.7 GeV to 2.76 TeV. kT is estimated with the help of event-byevent charged particle multiplicity fluctuations from experiment. Dynamical fluctuations are extracted by removing the statistical fluctuations obtained from the participant model. kT is also estimated from event generators AMPT, UrQMD, EPOS and a hadron resonance gas model. The values of isothermal compressibility are estimated for the Large Hadron Collider (LHC energies with the help of the event generators.

Detection of Puccinia kuehnii Causing Sugarcane Orange Rust with a Loop-Mediated Isothermal Amplification-Based Assay.

Science.gov (United States)

Chandra, Amaresh; Keizerweerd, Amber T; Grisham, Michael P

2016-03-01

Puccinia kuehnii is a fungal pathogen that causes orange rust in sugarcane, which is now prevalent in many countries. At the early stage of disease, it is almost indistinguishable from brown rust, which is caused by Puccinia melanocephala. Although several PCR assays are available to detect these diseases, the loop-mediated isothermal amplification (LAMP)-based assay has been reported to be more economical and easier to perform. Under isothermal conditions, DNA is amplified with high specificity and rapidity. Moreover, visual judgment of color change without further post-amplification processing makes the method convenient. The present study was undertaken to detect P. kuehnii genomic DNA using four primers corresponding to a unique DNA sequence of P. kuehnii. The LAMP assay was found to be optimal when 8 mM MgSO4 was used and the reaction was incubated at 63 °C for 90 min. Positive samples showed a color change from orange to green upon SYBR Green I dye addition. Specificity of the LAMP test was checked with DNA of P. melanocephala, which showed no reaction. Sensitivity of the LAMP method was observed to be the same as real-time PCR at 0.1 ng, thus providing a rapid and more affordable option for early disease detection.

Thermal analysis of near-isothermal compressed gas energy storage system

International Nuclear Information System (INIS)

Odukomaiya, Adewale; Abu-Heiba, Ahmad; Gluesenkamp, Kyle R.; Abdelaziz, Omar; Jackson, Roderick K.; Daniel, Claus; Graham, Samuel; Momen, Ayyoub M.

2016-01-01

Highlights: • A novel, high-efficiency, scalable, near-isothermal, energy storage system is introduced. • A comprehensive analytical physics-based model for the system is presented. • Efficiency improvement is achieved via heat transfer enhancement and use of waste heat. • Energy storage roundtrip efficiency (RTE) of 82% and energy density of 3.59 MJ/m"3 is shown. - Abstract: Due to the increasing generation capacity of intermittent renewable electricity sources and an electrical grid ill-equipped to handle the mismatch between electricity generation and use, the need for advanced energy storage technologies will continue to grow. Currently, pumped-storage hydroelectricity and compressed air energy storage are used for grid-scale energy storage, and batteries are used at smaller scales. However, prospects for expansion of these technologies suffer from geographic limitations (pumped-storage hydroelectricity and compressed air energy storage), low roundtrip efficiency (compressed air energy storage), and high cost (batteries). Furthermore, pumped-storage hydroelectricity and compressed air energy storage are challenging to scale-down, while batteries are challenging to scale-up. In 2015, a novel compressed gas energy storage prototype system was developed at Oak Ridge National Laboratory. In this paper, a near-isothermal modification to the system is proposed. In common with compressed air energy storage, the novel storage technology described in this paper is based on air compression/expansion. However, several novel features lead to near-isothermal processes, higher efficiency, greater system scalability, and the ability to site a system anywhere. The enabling features are utilization of hydraulic machines for expansion/compression, above-ground pressure vessels as the storage medium, spray cooling/heating, and waste-heat utilization. The base configuration of the novel storage system was introduced in a previous paper. This paper describes the results

A two-phase flow and non-isothermal agglomerate model for a proton exchange membrane (PEM) fuel cell

International Nuclear Information System (INIS)

Xing, Lei; Liu, Xiaoteng; Alaje, Taiwo; Kumar, Ravi; Mamlouk, Mohamed; Scott, Keith

2014-01-01

A two dimensional, across the channel, steady-state model for a proton exchange membrane fuel cell (PEMFC) is presented in which the non-isothermal model for temperature distribution, the two-phase flow model for liquid water transport and the agglomerate model for oxygen reduction reaction are fully coupled. This model is used to investigate thermal transport within the membrane electrode assembly (MEA) associated with the combinational water phase-transfer and transport mechanisms. Effective temperature distribution strategies are established aim to enhance the cell performance. Agglomerate assumption is adopted in which the ionomer and liquid water in turn cover the agglomerate to form the ionomer and liquid water films. Ionomer swelling is associated with the non-uniform distribution of the water content. The modelling results show that heat accumulates within the cathode catalyst layer under the channel. Higher operating temperature improves the cell performance by increasing the kinetics, reducing the liquid water saturation on the cathode and increasing the water carrying capacity of the anode gas. Applying higher temperature on the anode and enlarging the width ratio of the channel/rib could improve the cell performance. Higher cathode temperature decreases the oxygen mole fraction, resulting in an insufficient oxygen supply and a limitation of the cell performance. - Highlights: • The two-phase flow and non-isothermal model couple with the agglomerate model. • Oxygen diffusivity and solubility in Nafion ® relate to water content and temperature. • Higher anode operating temperature improves the fuel cell performance. • Insufficient oxygen supply limits cell performance at higher current densities

Engineered, Spatially Varying Isothermal Holds: Enabling Combinatorial Studies of Temperature Effects, as Applied to Metastable Titanium Alloy β-21S

International Nuclear Information System (INIS)

Martin, Brian; Colorado School of Mines, Golden, CO; Samimi, Peyman; Colorado School of Mines, Golden, CO; Collins, Peter

2017-01-01

A novel method to systematically vary temperature and thus study the resulting microstructure of a material is presented. This new method has the potential to be used in a combinatorial fashion, allowing the rapid study of thermal holds on microstructures to be conducted. This is demonstrated on a beta titanium alloy, where the thermal history has a strong effect on microstructure. It is informed by simulation and executed using the resistive heating capabilities of a Gleeble 3800 thermomechanical simulator. Spatially varying isothermal holds of 4 h were affected, where the temperature range of the multiple isothermal holds varied by ~175 °C.

Improved Isotherm Data for Adsorption of Methane on Activated Carbons

KAUST Repository

Loh, Wai Soong; Rahman, Kazi Afzalur; Chakraborty, Anutosh; Saha, Bidyut Baran; Choo, Yoo Sang; Khoo, Boo Cheong; Ng, Kim Choon

2010-01-01

This article presents the adsorption isotherms of methane onto two different types of activated carbons, namely, Maxsorb III and ACF (A-20) at temperatures from (5 to 75) °C and pressures up to 2.5 MPa. The volumetric technique has been employed

Moisture sorption isotherms and glass transition temperature of elecampe (Inula helenium L.) and burdock (Arctium lappa L.) roots at 25°C.

Science.gov (United States)

Cervenka, L; Kubínová, J; Juszczak, L; Witczak, M

2012-02-01

Sorption isotherms of elecampe (Inula helenium L.) and burdock (Arctium lappa L.) root samples were obtained at 25 °C. Elecampe exhibited hysteresis loop in the range of 0.35-0.90 a(w) , whereas burdock roots showed significant differences between adsorption and desorption isotherms from 0.65 to 0.80 a(w) . Blahovec-Yanniotis was considered to give the best fit over the whole range of a(w) tested. Various parameters describing the properties of sorbed water derived from GAB, Henderson and Blahovec-Yanniotis models have been discussed. Differential scanning calorimetric method was used to measure the glass transition temperature (T (g)) of root samples in relation to water activity. The safe moisture content was determined in 12.01 and 14.96 g/100 g d. b. for burdock and elecampe root samples at 25 °C, respectively. Combining the T (g) line with sorption isotherm in one plot, it was found that the glass transition temperature concept overestimated the temperature stability for both root samples.

Prediction of Pure Component Adsorption Equilibria Using an Adsorption Isotherm Equation Based on Vacancy Solution Theory

DEFF Research Database (Denmark)

Marcussen, Lis; Aasberg-Petersen, K.; Krøll, Annette Elisabeth

2000-01-01

An adsorption isotherm equation for nonideal pure component adsorption based on vacancy solution theory and the Non-Random-Two-Liquid (NRTL) equation is found to be useful for predicting pure component adsorption equilibria at a variety of conditions. The isotherm equation is evaluated successfully...... adsorption systems, spreading pressure and isosteric heat of adsorption are also calculated....

Non-isothermal effects on multi-phase flow in porous medium

DEFF Research Database (Denmark)

Singh, Ashok; Wang, W; Park, C. H.

2010-01-01

In this paper a ppT -formulation for non-isothermal multi-phase flow is given including diffusion and latent heat effects. Temperature and pressure dependencies of governing parameters are considered, in particular surface tension variation on phase interfaces along with temperature changes. A we...

Isotherm Studies of Equilibrium Sorption of Cu2+ and Cd2+ from Aqueous Solutions by Modified and Unmodified Breadfruit Seed Hull

Directory of Open Access Journals (Sweden)

Christopher Uchechukwu Sonde

2015-09-01

Full Text Available The ability of an economically cheap adsorbent material of natural origin, African breadfruit seed hull, was assessed for Cu(II and Cd(II ions’ adsorption from aqueous solutions. The effects of adsorbent dose, particle size and initial metal ion concentrations were investigated in a batch adsorption process. The experimental data were analyzed using five two-parameter isotherm equations (i.e., Langmuir, Freundlich, Temkin, Harkins-Jura and Halsey isotherm models. Freundlich and Halsey models provided the best description for the adsorption data while the other three models gave fairly good interpretation to the experimental adsorption data. The maximum adsorption capacity corresponding to saturation of sites (qmax, obtained from the Langmuir plots, were 7.76 and 8.06 mg g-1 for Cu(II and Cd(II onto the unmodified breadfruit seed hull (UBSH and 12.67 and 13.97 mg g-1, respectively for Cu(II and Cd(II adsorption onto the modified breadfruit seed hull (MBSH. The experimental results showed that there was an enhancement in the removal of the metal ions by the mercaptoacetic acid-modified breadfruit seed hull. DOI: http://dx.doi.org/10.17807/orbital.v7i3.625 

Kinetics and adsorption isotherm of lactic acid from fermentation broth onto activated charcoal

Directory of Open Access Journals (Sweden)

Seankham Soraya

2017-01-01

Full Text Available Activated charcoal was applied for the recovery of lactic acid in undissociated form from fermentation broth. Lactic acid was obtained from the fermentation of Lactobacillus casei TISTR 1340 using acid hydrolyzed Jerusalem artichoke as a carbon source. The equilibrium adsorption isotherm and kinetics for the lactic acid separation were investigated. The experimental data for lactic acid adsorption from fermentation broth were best described by the Freundlich isotherm and the pseudo-second order kinetics with R2 values of 0.99. The initial adsorption rate was 41.32 mg/g⋅min at the initial lactic acid concentration of 40 g/L.

New closed tube loop mediated isothermal amplification assay for prevention of product cross-contamination.

Science.gov (United States)

Karthik, K; Rathore, Rajesh; Thomas, Prasad; Arun, T R; Viswas, K N; Dhama, Kuldeep; Agarwal, R K

2014-01-01

Loop mediated isothermal amplification (LAMP) assay, a promising diagnostic test, has been developed for detection of different pathogens of human as well as animals. Various positive points support its use as a field level test but the major problem is product cross contamination leading to false positive results. Different methods were adopted by various researchers to control this false positive amplification due to cross contamination but all have their own advantages and disadvantages. A new closed tube LAMP assay based on agar dye capsule was developed in the present study and this technique has some advantages over the other closed tube technique.•Agar at the concentration of 1.5% was used to sandwich SYBR green dye I with the aid of intradermal syringe. This agar dye capsule was placed over the LAMP reaction mixture before it was amplified.•To eliminate the hazardous nature of Ultra Violet (UV) light during result visualization of LAMP products, the present study demonstrates the use of Light Emitting Diode (LED) lights for result visualization.•LAMP was carried out for Brucella species detection using this modified techniques yielding good results without any cross contamination and LED showed similar fluorescence compared to UV.

Microstructure and magnetic behavior of Cu–Co–Si ternary alloy synthesized by mechanical alloying and isothermal annealing

Energy Technology Data Exchange (ETDEWEB)

Chabri, Sumit, E-mail: sumitchabri2006@gmail.com [Department of Metallurgy & Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Bera, S. [Department of Metallurgical & Materials Engineering, National Institute of Technology, Durgapur 713209 (India); Mondal, B.N. [Department of Central Scientific Services, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Basumallick, A.; Chattopadhyay, P.P. [Department of Metallurgy & Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India)

2017-03-15

Microstructure and magnetic behavior of nanocrystalline 50Cu–40Co–10Si (at%) alloy prepared by mechanical alloying and subsequent isothermal annealing in the temperature range of 450–650 °C have been studied. Phase evolution during mechanical alloying and isothermal annealing is characterized by X-ray diffraction (XRD), differential thermal analyzer (DTA), high resolution transmission electron microscopy (HRTEM) and magnetic measurement. Addition of Si has been found to facilitate the metastable alloying of Co in Cu resulting into the formation of single phase solid solution having average grain size of 9 nm after ball milling for 50 h duration. Annealing of the ball milled alloy improves the magnetic properties significantly and best combination of magnetic properties has been obtained after annealing at 550 °C for 1 h duration.

A capillary-based multiplexed isothermal nucleic acid-based test for sexually transmitted diseases in patients.

Science.gov (United States)

Xu, Gaolian; Zhao, Hang; Cooper, Jonathan M; Reboud, Julien

2016-10-06

We demonstrate a multiplexed loop mediated isothermal amplification (LAMP) assay for infectious disease diagnostics, where the analytical process flow of target pathogens genomic DNA is performed manually by moving magnetic beads through a series of plugs in a capillary. Heat is provided by a water bath and the results are read by the naked eye, enabling applications in low resource settings.

Kinetic and Isotherm Modelling of the Adsorption of Phenolic Compounds from Olive Mill Wastewater onto Activated Carbon

Directory of Open Access Journals (Sweden)

Alessandro A. Casazza

2015-01-01

Full Text Available The adsorption of phenolic compounds from olive oil wastewater by commercial activated carbon was studied as a function of adsorbent quantity and temperature. The sorption kinetics and the equilibrium isotherms were evaluated. Under optimum conditions (8 g of activated carbon per 100 mL, the maximum sorption capacity of activated carbon expressed as mg of caff eic acid equivalent per g of activated carbon was 35.8 at 10 °C, 35.4 at 25 °C and 36.1 at 40 °C. The pseudo-second-order model was considered as the most suitable for kinetic results, and Langmuir isotherm was chosen to bett er describe the sorption system. The results confi rmed the effi ciency of activated carbon to remove almost all phenolic compound fractions from olive mill effl uent. The preliminary results obtained will be used in future studies. The carbohydrate fraction of this upgraded residue could be employed to produce bioethanol, and adsorbed phenolic compounds can be recovered and used in different industries.

The Application of Simulation Method in Isothermal Elastic Natural Gas Pipeline

Science.gov (United States)

Xing, Chunlei; Guan, Shiming; Zhao, Yue; Cao, Jinggang; Chu, Yanji

2018-02-01

This Elastic pipeline mathematic model is of crucial importance in natural gas pipeline simulation because of its compliance with the practical industrial cases. The numerical model of elastic pipeline will bring non-linear complexity to the discretized equations. Hence the Newton-Raphson method cannot achieve fast convergence in this kind of problems. Therefore A new Newton Based method with Powell-Wolfe Condition to simulate the Isothermal elastic pipeline flow is presented. The results obtained by the new method aregiven based on the defined boundary conditions. It is shown that the method converges in all cases and reduces significant computational cost.

Synthesis and kinetics of non-isothermal degradation of acetylene terminated silazane

Institute of Scientific and Technical Information of China (English)

Wei Jian Han; Li Ye; Ji Dong Hu; Tong Zhao

2011-01-01

Novel acetylene terminated silazane compounds, with three types of substituent, were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene (3-APA). Thermal property of the compounds is studied by thermogravimetry analysis (TGA). It shows that the acetylene terminated silazane has high temperature resistance. The char yield at 1000℃ is 77.6, 81.9 and 68.7 wt% for methyl, vinyl, and phenyl substituted silazane, respectively. The pyrolysis kinetics of the silazane is investigated by non-isothermal thermogravimetric measurement. The pyrolysis undergoes three stages, which is resolved by PEAKFIT. The kinetic parameters are calculated by the Kissinger method. The role of functionalities on the thermal resistance is discussed. The vinyl-silazane exhibits higher thermal stability because of higher cross-linking density.

The effects of non-isothermal deformation on martensitic transformation in 22MnB5 steel

International Nuclear Information System (INIS)

Naderi, M.; Saeed-Akbari, A.; Bleck, W.

2008-01-01

In the present paper, the effects of process parameters on phase transformations during non-isothermal deformations are described and discussed. Non-isothermal high temperature compressive deformations were conducted on 22MnB5 boron steel by using deformation dilatometry. Cylindrical samples were uniaxially deformed at different strain rates ranging from 0.05 to 1.0 s -1 to a maximum compressive strain of 50%. Qualitative and quantitative investigations were carried out using surface hardness mapping data as well as dilatation curves. It was observed that a higher initial deformation temperatures resulted in a higher martensite fraction of the microstructure, while a variation in the martensite start temperature was negligible. Another conclusion was that by applying larger amounts of strain as well as higher force levels, not only the martensite start temperature, but also the amount of martensite was reduced. Moreover, it was concluded that using surface hardness mapping technique and dilatometry experiments were very reliable methods to quantify and qualify the coexisting phases

The effects of non-isothermal deformation on martensitic transformation in 22MnB5 steel

Energy Technology Data Exchange (ETDEWEB)

Naderi, M. [Department of Materials Science and Engineering, Faculty of Engineering, Arak University, Shariati Street, Arak (Iran, Islamic Republic of)], E-mail: malek.naderi@iehk.rwth-aachen.de; Saeed-Akbari, A.; Bleck, W. [Department of Ferrous Metallurgy, RWTH Aachen University, Aachen (Germany)

2008-07-25

In the present paper, the effects of process parameters on phase transformations during non-isothermal deformations are described and discussed. Non-isothermal high temperature compressive deformations were conducted on 22MnB5 boron steel by using deformation dilatometry. Cylindrical samples were uniaxially deformed at different strain rates ranging from 0.05 to 1.0 s{sup -1} to a maximum compressive strain of 50%. Qualitative and quantitative investigations were carried out using surface hardness mapping data as well as dilatation curves. It was observed that a higher initial deformation temperatures resulted in a higher martensite fraction of the microstructure, while a variation in the martensite start temperature was negligible. Another conclusion was that by applying larger amounts of strain as well as higher force levels, not only the martensite start temperature, but also the amount of martensite was reduced. Moreover, it was concluded that using surface hardness mapping technique and dilatometry experiments were very reliable methods to quantify and qualify the coexisting phases.

Demonstration of Isothermal Compressed Air Energy Storage to Support Renewable Energy Production

Energy Technology Data Exchange (ETDEWEB)

Bollinger, Benjamin [Sustainx, Incorporated, Seabrook, NH (United States)

2015-01-02

This project develops and demonstrates a megawatt (MW)-scale Energy Storage System that employs compressed air as the storage medium. An isothermal compressed air energy storage (ICAES^TM) system rated for 1 MW or more will be demonstrated in a full-scale prototype unit. Breakthrough cost-effectiveness will be achieved through the use of proprietary methods for isothermal gas cycling and staged gas expansion implemented using industrially mature, readily-available components.The ICAES approach uses an electrically driven mechanical system to raise air to high pressure for storage in low-cost pressure vessels, pipeline, or lined-rock cavern (LRC). This air is later expanded through the same mechanical system to drive the electric motor as a generator. The approach incorporates two key efficiency-enhancing innovations: (1) isothermal (constant temperature) gas cycling, which is achieved by mixing liquid with air (via spray or foam) to exchange heat with air undergoing compression or expansion; and (2) a novel, staged gas-expansion scheme that allows the drivetrain to operate at constant power while still allowing the stored gas to work over its entire pressure range. The ICAES system will be scalable, non-toxic, and cost-effective, making it suitable for firming renewables and for other grid applications.

Loop-mediated isothermal amplification (LAMP) shield for Arduino DNA detection

NARCIS (Netherlands)

Velders, Aldrik H.; Schoen, Cor; Saggiomo, Vittorio

2018-01-01

Objective: Loop-mediated isothermal amplification (LAMP) of DNA is gaining relevance as a method to detect nucleic acids, as it is easier, faster, and more powerful than conventional Polymerase Chain Reaction. However, LAMP is still mostly used in laboratory settings, because of the lack of a cheap

Isothermal dehydration of thin films of water and sugar solutions

Energy Technology Data Exchange (ETDEWEB)

Heyd, R. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Rampino, A. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Bellich, B.; Elisei, E. [Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Cesàro, A. [Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Elettra Sincrotrone Trieste, Area Science Park, I-34149 Trieste (Italy); Saboungi, M.-L. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC), Sorbonne Univ-UPMC, Univ Paris 06, UMR CNRS 7590, Museum National d’Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, F-75005 Paris (France)

2014-03-28

The process of quasi-isothermal dehydration of thin films of pure water and aqueous sugar solutions is investigated with a dual experimental and theoretical approach. A nanoporous paper disk with a homogeneous internal structure was used as a substrate. This experimental set-up makes it possible to gather thermodynamic data under well-defined conditions, develop a numerical model, and extract needed information about the dehydration process, in particular the water activity. It is found that the temperature evolution of the pure water film is not strictly isothermal during the drying process, possibly due to the influence of water diffusion through the cellulose web of the substrate. The role of sugar is clearly detectable and its influence on the dehydration process can be identified. At the end of the drying process, trehalose molecules slow down the diffusion of water molecules through the substrate in a more pronounced way than do the glucose molecules.

Multivariate curve resolution using a combination of mid-infrared and near-infrared spectra for the analysis of isothermal epoxy curing reaction

Science.gov (United States)

Yamasaki, Hideki; Morita, Shigeaki

2018-05-01

Multivariate curve resolution (MCR) was applied to a hetero-spectrally combined dataset consisting of mid-infrared (MIR) and near-infrared (NIR) spectra collected during the isothermal curing reaction of an epoxy resin. An epoxy monomer, bisphenol A diglycidyl ether (BADGE), and a hardening agent, 4,4‧-diaminodiphenyl methane (DDM), were used for the reaction. The fundamental modes of the Nsbnd H and Osbnd H stretches were highly overlapped in the MIR region, while their first overtones could be independently identified in the NIR region. The concentration profiles obtained by MCR using the hetero-spectral combination showed good agreement with the results of calculations based on the Beer-Lambert law and the mass balance. The band assignments and absorption sites estimated by the analysis also showed good agreement with the results using two-dimensional (2D) hetero-correlation spectroscopy.

On the effect of optical and isothermal treatments on luminescence signals from feldspars

International Nuclear Information System (INIS)

Pagonis, Vasilis; Polymeris, George; Kitis, George

2015-01-01

During luminescence dosimetry and luminescence dating applications it is often necessary to precondition the geological samples by applying a thermal or optical treatment before measuring the luminescence signal. In luminescence applications using apatites or feldspars, measurement of continuous-wave infrared or optically stimulated signals (CW-IRSL and CW-OSL) are customarily preceded by either an isothermal heating of the samples at a fixed temperature for a short time interval, or alternatively by optically bleaching the samples using light from LEDs with the appropriate wavelength. This paper presents new analytical equations which can be used to describe these commonly employed double experimental procedures. The equations are based on a recently published model which assumes that tunneling processes are taking place in random distributions of donor–acceptor pairs. The concentration of charge carriers during the CW-IRSL or CW-OSL experiment is expressed in terms of the parameters of the preceding thermal or optical bleaching procedure, and depends also on the distribution of distances between electron and hole pairs. The analytical equations in this paper are compared with experimental data from a feldspar sample which undergoes an isothermal procedure followed by measurement of the CW-IRSL signal. Additional comparisons with experiment are provided using a feldspar sample which undergoes an infrared bleaching process, followed by measurement of the CW-OSL signal. These results and conditions under which the equations can be used are discussed within the framework of the model. - Highlights: • CW-IRSL and CW-OSL measurements are preceded by heating or optical bleaching. • New analytical equations are derived to describe these double experimental procedures. • Equations are compared with data from a feldspar sample following isothermal procedure. • Equations are compared with data from a feldspar sample following optical bleaching.

Molecular simulation of excess isotherm and excess enthalpy change in gas-phase adsorption.

Science.gov (United States)

Do, D D; Do, H D; Nicholson, D

2009-01-29

We present a new approach to calculating excess isotherm and differential enthalpy of adsorption on surfaces or in confined spaces by the Monte Carlo molecular simulation method. The approach is very general and, most importantly, is unambiguous in its application to any configuration of solid structure (crystalline, graphite layer or disordered porous glass), to any type of fluid (simple or complex molecule), and to any operating conditions (subcritical or supercritical). The behavior of the adsorbed phase is studied using the partial molar energy of the simulation box. However, to characterize adsorption for comparison with experimental data, the isotherm is best described by the excess amount, and the enthalpy of adsorption is defined as the change in the total enthalpy of the simulation box with the change in the excess amount, keeping the total number (gas + adsorbed phases) constant. The excess quantities (capacity and energy) require a choice of a reference gaseous phase, which is defined as the adsorptive gas phase occupying the accessible volume and having a density equal to the bulk gas density. The accessible volume is defined as the mean volume space accessible to the center of mass of the adsorbate under consideration. With this choice, the excess isotherm passes through a maximum but always remains positive. This is in stark contrast to the literature where helium void volume is used (which is always greater than the accessible volume) and the resulting excess can be negative. Our definition of enthalpy change is equivalent to the difference between the partial molar enthalpy of the gas phase and the partial molar enthalpy of the adsorbed phase. There is no need to assume ideal gas or negligible molar volume of the adsorbed phase as is traditionally done in the literature. We illustrate this new approach with adsorption of argon, nitrogen, and carbon dioxide under subcritical and supercritical conditions.

Genotyping three SNPs affecting warfarin drug response by isothermal real-time HDA assays.

Science.gov (United States)

Li, Ying; Jortani, Saeed A; Ramey-Hartung, Bronwyn; Hudson, Elizabeth; Lemieux, Bertrand; Kong, Huimin

2011-01-14

The response to the anticoagulant drug warfarin is greatly affected by genetic polymorphisms in the VKORC1 and CYP2C9 genes. Genotyping these polymorphisms has been shown to be important in reducing the time of the trial and error process for finding the maintenance dose of warfarin thus reducing the risk of adverse effects of the drug. We developed a real-time isothermal DNA amplification system for genotyping three single nucleotide polymorphisms (SNPs) that influence warfarin response. For each SNP, real-time isothermal Helicase Dependent Amplification (HDA) reactions were performed to amplify a DNA fragment containing the SNP. Amplicons were detected by fluorescently labeled allele specific probes during real-time HDA amplification. Fifty clinical samples were analyzed by the HDA-based method, generating a total of 150 results. Of these, 148 were consistent between the HDA-based assays and a reference method. The two samples with unresolved HDA-based test results were repeated and found to be consistent with the reference method. The HDA-based assays demonstrated a clinically acceptable performance for genotyping the VKORC1 -1639G>A SNP and two SNPs (430C>T and 1075A>C) for the CYP2C9 enzyme (CYP2C9*2 and CYP2C9*3), all of which are relevant in warfarin pharmacogenentics. Copyright © 2010 Elsevier B.V. All rights reserved.

Isothermal and isochronal annealing methodology to study post-irradiation temperature activated phenomena

International Nuclear Information System (INIS)

Chabrerie, C.; Autran, J.L.; Paillet, P.; Flament, O.; Leray, J.L.; Boudenot, J.C.

1997-01-01

In this work, the evolution of the oxide trapped charge has been modeled, to predict post-irradiation behavior for arbitrary anneal conditions (i.e., arbitrary temperature-time profiles). Using experimental data obtained from a single isochronal anneal, the method consists of calculating the evolution of the energy distribution of the oxide trapped charge, in the framework of a thermally activated charge detrapping model. This methodology is illustrated in this paper by the prediction of experimental isothermal data from isochronal measurements. The implications of these results to hardness assurance test methods are discussed

Detection of Enterovirus 71 gene from clinical specimens by reverse-transcription loop-mediated isothermal amplification

OpenAIRE

D Wang; X Wang; Y Geng; C An

2014-01-01

Purpose : The objective of this study was to develop a sensitive, specific and rapid approach to diagnose hand foot and mouth disease (HFMD) for an early treatment by using loop-mediated isothermal amplification (LAMP) technique. Materials and Methods : A reverse-transcription loop-mediated isothermal amplification (RT-LAMP) for detecting EV71 virus was developed, the specificity and sensitivity of RT-LAMP was tested, and the clinical specimens was assayed by the RT-LAMP comparing with conven...

Isothermal Amplification and Lateral-Flow Assay for Detecting Crown-Gall-Causing Agrobacterium spp.

Science.gov (United States)

Fuller, Skylar L; Savory, Elizabeth A; Weisberg, Alexandra J; Buser, Jessica Z; Gordon, Michael I; Putnam, Melodie L; Chang, Jeff H

2017-09-01

Agrobacterium is a genus of soilborne gram-negative bacteria. Members carrying oncogenic plasmids can cause crown gall disease, which has significant economic costs, especially for the orchard and nursery industries. Early and rapid detection of pathogenic Agrobacterium spp. is key to the management of crown gall disease. To this end, we designed oligonucleotide primers and probes to target virD2 for use in a molecular diagnostic tool that relies on isothermal amplification and lateral-flow-based detection. The oligonucleotide tools were tested in the assay and evaluated for detection limit and specificity in detecting alleles of virD2. One set of primers that successfully amplified virD2 when used with an isothermal recombinase was selected. Both tested probes had detection limits in picogram amounts of DNA. Probe 1 could detect all tested pathogenic isolates that represented most of the diversity of virD2. Finally, the coupling of lateral-flow detection to the use of these oligonucleotide primers in isothermal amplification helped to reduce the onerousness of the process, and alleviated reliance on specialized tools necessary for molecular diagnostics. The assay is an advancement for the rapid molecular detection of pathogenic Agrobacterium spp.

Dynamics of gas bubble growth in oil-refrigerant mixtures under isothermal decompression

Energy Technology Data Exchange (ETDEWEB)

Dias, Joao Paulo; Barbosa Junior, Jader R.; Prata, Alvaro T. [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. of Mechanical Engineering], Emails: jpdias@polo.ufsc.br, jrb@polo.ufsc.br, prata@polo.ufsc.br

2010-07-01

This paper proposes a numerical model to predict the growth of gaseous refrigerant bubbles in oil-refrigerant mixtures with high contents of oil subjected to isothermal decompression. The model considers an Elementary Cell (EC) in which a spherical bubble is surrounded by a concentric and spherical liquid layer containing a limited amount of dissolved liquid refrigerant. The pressure reduction in the EC generates a concentration gradient at the bubble interface and the refrigerant is transported to the bubble by molecular diffusion. After a sufficiently long period of time, the concentration gradient in the liquid layer and the bubble internal pressure reach equilibrium and the bubble stops growing, having attained its stable radius. The equations of momentum and chemical species conservation for the liquid layer, and the mass balance at the bubble interface are solved via a coupled finite difference procedure to determine the bubble internal pressure, the refrigerant radial concentration distribution and the bubble growth rate. Numerical results obtained for a mixture of ISO VG10 ester oil and refrigerant HFC-134a showed that bubble growth dynamics depends on model parameters like the initial bubble radius, initial refrigerant concentration in the liquid layer, decompression rate and EC temperature. Despite its simplicity, the model showed to be a potential tool to predict bubble growth and foaming which may result from important phenomena occurring inside refrigeration compressors such as lubrication of sliding parts and refrigerant degassing from the oil stored in oil sump during compressor start-up. (author)

Loop-mediated isothermal amplification for detection of Staphylococcus aureus in dairy cow suffering from mastitis.

Science.gov (United States)

Tie, Zhang; Chunguang, Wang; Xiaoyuan, Wei; Xinghua, Zhao; Xiuhui, Zhong

2012-01-01

To develop a rapid detection method of Staphylococcus aureus using loop-mediated isothermal amplification (LAMP), four specific primers were designed according to six distinct sequences of the nuc gene. In addition, the specificity and sensitivity of LAMP were verified and compared with those of PCR. Results showed that the LAMP reaction was completed within 45 min at 62.5°C, and ladder bands were appeared in LAMP products analyzed by gel electrophoresis. After adding 1x SYBR Green l, the positive reaction tube showed green color and the negative reaction tube remained orange, indicating that the LAMP has high specificity. The minimal detectable concentration of LAMP was 1 × 10² CFU/mL and that of PCR was 1 × 10⁴ CFU/mL, indicating that the LAMP was 100 times more sensitive than the PCR. The LAMP method for detection of Staphylococcus aureus has many advantages, such as simple operation, high sensitivity, high specificity, and rapid analysis. Therefore, this method is more suitable for the rapid on-site detection of Staphylococcus aureus.

3D imaging using X-Ray tomography and SEM combined FIB to study non isothermal creep damage of (111) oriented samples of γ / γ ′ nickel base single crystal superalloy MC2

KAUST Repository

Jouiad, Mustapha

2012-01-01

An unprecedented investigation consisting of the association of X-Ray tomography and Scanning Electron Microscopy combined with Focus Ion Beam (SEM-FIB) is conducted to perform a 3D reconstruction imaging. These techniques are applied to study the non-isothermal creep behavior of close (111) oriented samples of MC2 nickel base superalloys single crystal. The issue here is to develop a strategy to come out with the 3D rafting of γ\\' particles and its interaction whether with dislocation structures or/and with the preexisting voids. This characterization is uncommonly performed away from the conventional studied orientation [001] in order to feed the viscoplastic modeling leading to its improvement by taking into account the crystal anisotropy. The creep tests were performed at two different conditions: classical isothermal tests at 1050°C under 140 MPa and a non isothermal creep test consisting of one overheating at 1200°C and 30 seconds dwell time during the isothermal creep life. The X-Ray tomography shows a great deformation heterogeneity that is pronounced for the non-isothermal tested samples. This deformation localization seems to be linked to the preexisting voids. Nevertheless, for both tested samples, the voids coalescence is the precursor of the observed damage leading to failure. SEM-FIB investigation by means of slice and view technique gives 3D views of the rafted γ\\' particles and shows that γ corridors evolution seems to be the main creep rate controlling parameter. © 2012 Trans Tech Publications, Switzerland.

Pressure-area isotherm of a lipid monolayer from molecular dynamics simulations

NARCIS (Netherlands)

Baoukina, Svetlana; Monticelli, Luca; Marrink, Siewert J.; Tieleman, D. Peter

2007-01-01

We calculated the pressure-area isotherm of a dipalmitoyl-phosphatidylcholine (DPPC) lipid monolayer from molecular dynamics simulations using a coarse-grained molecular model. We characterized the monolayer structure, geometry, and phases directly from the simulations and compared the calculated

Nonequilibrium Contribution to the Rate of Reaction. III. Isothermal Multicomponent Systems

Science.gov (United States)

Shizgal, B.; Karplus, M.

1970-10-01

The nonequilibrium contribution to the reaction rate of an isothermal multicomponent system is obtained by solution of the appropriate Chapman-Enskog equation; the system is composed of reactive species in contact with a heat bath of inert atoms M.

The development of modulated, quasi-isothermal and ultraslow thermal methods as a means of characterizing the α to γ indomethacin polymorphic transformation.

Science.gov (United States)

Qi, Sheng; Craig, Duncan Q M

2012-05-07

While polymorphism remains a key issue within the pharmaceutical and related industries, the understanding of the transformation process itself remains relatively poorly understood. In this study we use a combination of conventional and modulated temperature differential scanning calorimetry (MTDSC), quasi-isothermal MTDSC (Qi-MTDSC) and ultraslow heating rate MTDSC as a novel means of investigating the temperature-induced α to γ transformation in indomethacin, using hot stage microscopy and variable temperature attenuated total reflectance FTIR spectroscopy as supportive techniques. In particular, we utilize the ability of MTDSC to measure subtle heat capacity changes through the transformation, we examine the use of Lissajous analysis of the modulated heating signal itself (both scanning and quasi-isothermal) and finally we investigate the use of ultraslow heating rates (down to 0.04 °C/min) so as to facilitate examination of the melt-crystallization process at a scanning rate whereby kinetic hindrance becomes negligible. Indomethacin was prepared in the metastable α and stable γ forms using standard approaches. Samples were studied using conventional DSC, Qi-MTDSC (involving holding and modulating the sample at a series of incremental temperature steps) and ultraslow MTDSC. All studies were conducted using a Q-1000 MTDSC using crimped pans, following standard calibration procedures. Conventional DSC at 10 °C/min showed the expected single melting responses for the α and γ forms, while MTDSC at slower rates indicated the presence of a melt-crystallization process. Quasi-isothermal studies allowed the heat capacity to be estimated as a function of time, while the associated Lissajous analysis demonstrated distortion of the elliptical response as a result of the kinetic events involved. Ultraslow heating resulted in superimposition of the melting and crystallization processes, resulting in a discrete thermal event that was enthalpically equivalent to the

New closed tube loop mediated isothermal amplification assay for prevention of product cross-contamination

OpenAIRE

Karthik, K.; Rathore, Rajesh; Thomas, Prasad; Arun, T.R.; Viswas, K.N.; Dhama, Kuldeep; Agarwal, R.K.

2014-01-01

Loop mediated isothermal amplification (LAMP) assay, a promising diagnostic test, has been developed for detection of different pathogens of human as well as animals. Various positive points support its use as a field level test but the major problem is product cross contamination leading to false positive results. Different methods were adopted by various researchers to control this false positive amplification due to cross contamination but all have their own advantages and disadvantages. A...

Thermal fatigue appears to be more damaging than uniaxial isothermal fatigue for the austentic stainless steels, and application of multiaxial fatigue criteria

Energy Technology Data Exchange (ETDEWEB)

Fissolo, Antoine; Gourdin, Cedric [DM2S/SEMT/LISN, Gif sur Yvette (France); Vincent, Ludovic [DMN/SRMA/LCD, Gif sur Yvette (France)

2009-07-01

For nuclear reactor components, uniaxial isothermal fatigue curves are used to estimate the crack initiation under thermal fatigue. However, such approach would be not sufficient in some cases where cracking was observed. To investigate differences between uniaxial and thermal fatigue damage, tests have been carried out at CEA using the thermal fatigue devices SPLASH and FAT3D: a bi-dimensional (2-D) loading status is obtained in SPLASH, whereas a tri-dimensional (3-D) loading status is obtained in FAT3D. All the analysed tests clearly show that crack initiation in thermal fatigue is faster than in uniaxial isothermal fatigue conditions: for identical levels of strain, the number of cycles required to achieve crack initiation is significantly lower. The enhanced damaging effect probably results from a pure mechanical origin: a nearly perfect biaxial state corresponds to an increased hydrostatic stress. Consequently, multiaxial fatigue criteria must be applied. The Zamrik's strain criterion and the energy criterion proposed by Ecole Polytechnique provide the best estimations. In that framework, the proposed new method coupling both RCC-MR strain estimations and Zamrik's criterion appears to be more promising for the designer. (orig.)

Thermal fatigue appears to be more damaging than uniaxial isothermal fatigue for the austentic stainless steels, and application of multiaxial fatigue criteria

International Nuclear Information System (INIS)

Fissolo, Antoine; Gourdin, Cedric; Vincent, Ludovic

2009-01-01

For nuclear reactor components, uniaxial isothermal fatigue curves are used to estimate the crack initiation under thermal fatigue. However, such approach would be not sufficient in some cases where cracking was observed. To investigate differences between uniaxial and thermal fatigue damage, tests have been carried out at CEA using the thermal fatigue devices SPLASH and FAT3D: a bi-dimensional (2-D) loading status is obtained in SPLASH, whereas a tri-dimensional (3-D) loading status is obtained in FAT3D. All the analysed tests clearly show that crack initiation in thermal fatigue is faster than in uniaxial isothermal fatigue conditions: for identical levels of strain, the number of cycles required to achieve crack initiation is significantly lower. The enhanced damaging effect probably results from a pure mechanical origin: a nearly perfect biaxial state corresponds to an increased hydrostatic stress. Consequently, multiaxial fatigue criteria must be applied. The Zamrik's strain criterion and the energy criterion proposed by Ecole Polytechnique provide the best estimations. In that framework, the proposed new method coupling both RCC-MR strain estimations and Zamrik's criterion appears to be more promising for the designer. (orig.)

Moisture ingress into electronics enclosures under isothermal conditions

International Nuclear Information System (INIS)

Staliulionis, Ž.; Jabbari, M.; Hattel, J. H.

2016-01-01

The number of electronics used in outdoor environment is constantly growing. The humidity causes about 19 % of all electronics failures and, especially, moisture increases these problems due to the ongoing process of miniaturization and lower power consumption of electronic components. Moisture loads are still not understood well by design engineers, therefore this field has become one of the bottlenecks in the electronics system design. The objective of this paper is to model moisture ingress into an electronics enclosure under isothermal conditions. The moisture diffusion model is based on a 1D quasi-steady state (QSS) approximation for Fick’s second law. This QSS approach is also described with an electrical analogy which gives a fast tool in modelling of the moisture response. The same QSS method is applied to ambient water vapour variations. The obtained results are compared to an analytical solution and very good agreement is found.

Survival of encapsulated Lactobacillus plantarum during isothermal heating and bread baking

NARCIS (Netherlands)

Zhang, L.; Chen, Xiao Dong; Boom, R.M.; Schutyser, M.A.I.

2018-01-01

The effect of encapsulation on the survival of Lactobacillus plantarum during isothermal heating and bread baking was investigated. Four encapsulating materials were evaluated, i.e., reconstituted skim milk (RSM), gum arabic (GA), maltodextrin (MD) and inulin. Freeze dried bacteria survived better

A general approach for defining the macroscopic free energy density of saturated porous media at finite strains under non-isothermal conditions

International Nuclear Information System (INIS)

Gajo, A.

2011-01-01

A general approach is proposed for defining the macroscopic free energy density function (and its complement, the free enthalpy) of a saturated porous medium submitted to finite deformations under non-isothermal conditions, in the case of compressible fluid and solid constituents. Reference is made to an elementary volume treated as an 'open system', moving with the solid skeleton. The proposed free energy depends on the generalised strains (namely an appropriate measure of the strain of the solid skeleton and the variation in fluid mass content) and the absolute temperatures of the solid and fluid phases (which are assumed to differ from each other for the sake of generality). This macroscopic energy proves to be a potential for the generalised stresses (namely the associated measure of the total stress and the free enthalpy of the pore fluid per unit mass) and the entropies of the solid and fluid phases. In contrast with mixture theories, the resulting free energy is not the simple sum of the free energies of the single constituents. Two simplified cases are examined in detail, i.e. the semi-linear theory (originally proposed for isothermal conditions and extended here to non-isothermal problems) and the linear theory. The proposed approach paves the way to the consistent non-isothermal-hyper-elastic-plastic modelling of saturated porous media with a compressible fluid and solid constituents. (authors)

RELAP5 progress summary: simulation of semiscale isothermal blowdown (Test S-01-4A)

International Nuclear Information System (INIS)

Kuo, H.H.; Wagner, R.J.; Carlson, K.E.; Kiser, D.M.; Trapp, J.A.; Ransom, V.H.

1978-07-01

The RELAP5/MOD''O'' LOCA analysis code has been applied to Simulation of the Semiscale Isothermal Blowdown Test (S-01-4A) from initiation to 60 seconds. Subcooled ECC injection was simulated from 23 seconds until accumulator emptying. The calculated results are in very good agreement with the experimental data. This is the first full system application of the RELAP5 code and only the pressurizer surge line resistance was modified to achieve the results reported. An analysis of the code execution time using a time-step statistical edit is included

Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot

Directory of Open Access Journals (Sweden)

R. Prasad

2011-01-01

Full Text Available To comply with the stringent emission regulations on soot, diesel vehicles manufacturers more and more commonly use diesel particulate filters (DPF. These systems need to be regenerated periodically by burning soot that has been accumulated during the loading of the DPF. Design of the DPF requires rate of soot oxidation. This paper describes the kinetics of catalytic oxidation of diesel soot with air under isothermal conditions. Kinetics data were collected in a specially designed mini-semi-batch reactor. Under the high air flow rate assuming pseudo first order reaction the activation energy of soot oxidation was found to be, Ea = 160 kJ/ mol. ©2010 BCREC UNDIP. All rights reserved(Received: 14th June 2010, Revised: 18th July 2010, Accepted: 9th August 2010[How to Cite: R. Prasad, V.R. Bella. (2010. Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot. Bulletin of Chemical Reaction Engineering and Catalysis, 5(2: 95-101. doi:10.9767/bcrec.5.2.796.95-101][DOI:http://dx.doi.org/10.9767/bcrec.5.2.796.95-101 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/796]Cited by in: ACS 1 |

Adsorption of a cationic dye (Yellow Basic 28 ontothe calcined mussel shells: Kinetics, Isotherm and Thermodynamic Parameters

Directory of Open Access Journals (Sweden)

Imane EL Ouahabi

2015-11-01

Full Text Available The aim of this study is to valorise the mussel shells and evaluate the adsorption capacity of calcined mussel shells for the cationic dyes.  The adsorbent was characterized by DRX, FTIR, BET and SEM, respectively. The adsorption of Yellow Basic28 on calcined mussel shells was investigated using the parameters such as concentrations (10-50mg/L, pH (3-10, ionic strength (0-2 mol / L and temperature (288 - 318 °C.  The adsorption rate data were analysed according to the first and second-order kinetic models.  The adsorption kinetics was found to be best represented by the pseudo-second-order kinetic model.  The experimental isotherm data were analyzed using Langmuir, Freundlich, Temkin, Elovich and Dubinin–Radushkevich isotherm equations on the dye-adsorbent system. The experimental data yielded excellent fits with Freundlich isotherm equation (R² = 0.966. It was indicative of the heterogeneity of the adsorption sites on the CMS particles.  Various thermodynamic parameters such as enthalpy of adsorption ΔH°, free energy change ΔG°and entropy ΔS° were estimated.  The positive value of ΔH°(30.321 kJ/mol and negative values of ΔG° (from -5.392 to -2.873 kJ/mol show the process is endothermic and spontaneous.  The negative value of entropy ΔS° (-87.172 J/mol K suggest the decreased randomness at the solid-liquid interface during the adsorption of dyes onto calcined mussel shells.

Microstructure, Texture Evolution and Mechanical Properties of VT3-1 Titanium Alloy Processed by Multi-Pass Drawing and Subsequent Isothermal Annealing

Directory of Open Access Journals (Sweden)

Xiaofei Lei

2017-04-01

Full Text Available Microstructure, texture evolution, and mechanical properties of Ti–6Al–1.5Cr–2.5Mo–0.5Fe–0.3Si (VT3-1 titanium alloy processed by multi-pass drawing and subsequent isothermal annealing were systematically investigated. A fiber-like microstructure is formed after warm drawing at 760 °C with 60% area reduction. After isothermal annealing, the samples deformed to different amounts of area reduction show a similar volume fraction (80% of α phase, while the sample deformed to 60% exhibits a homogeneous microstructure with a larger grain size (5.8 μm. The major texture component of α phase developed during warm drawing is centered at a position of {φ1 = 10°, φ = 65°, φ2 = 0°}. The textures for annealed samples are almost along the orientation of original deformation textures and show significant increases in orientation density and volume fraction compared with their deformed states. In addition, for the drawn samples, the ultimate tensile strength increases but the ductility decreases with increasing drawing deformation. A negative slope of yield strength of annealed samples versus grain size (d−1/2 is found due to the difference between texture softening for as-rolled + annealed state and texture hardening for drawn + annealed state. The mechanical properties of annealed samples are found to be strongly dependent on grain size and texture, resulting in the balance of the strength and ductility.

A new apparatus for the determination of adsorption isotherms and adsorption enthalpies on microporous and meso-porous media

International Nuclear Information System (INIS)

Mouahid, A.

2010-01-01

A specific thermostated experimental device comprising a differential heat flow calorimeter coupled with a home built manometric system has been built for the simultaneous determination of adsorption isotherms and adsorption enthalpies. The differential heat flow calorimeter is a Tian Calvet Setaram C80 model which measures the heat flux of a gas and can be operated isothermally, the manometric system is a stainless steel homemade apparatus. This coupled apparatus allows measurements for pressure up to 2.5 MPa and temperature up to 423.15 K. On the one hand, the apparatus and the experimental procedures are described. On the second hand the reliability and reproducibility were established by measuring adsorption isotherms on a benchmark (Filtrasorb F400) at 318.15 K. The gravimetric method has been used at higher pressure at various temperatures. These devices allowed us to study the adsorption of supercritical fluid (nitrogen N 2 , methane CH 4 , carbon dioxide CO 2 ) in activated carbons and microporous or meso-porous silica. The adsorption of methane on a rock of type (TGR) was also studied. These experimental results are used for the study of the interactions fluid / solid that must be taken into account in molecular simulations or DFT theory. (author)

Direct detection of Mycobacterium avium in environmental water and scale samples by loop-mediated isothermal amplification.

Science.gov (United States)

Nishiuchi, Yukiko; Tamaru, Aki; Suzuki, Yasuhiko; Kitada, Seigo; Maekura, Ryoji; Tateishi, Yoshitaka; Niki, Mamiko; Ogura, Hisashi; Matsumoto, Sohkichi

2014-06-01

We previously demonstrated the colonization of Mycobacterium avium complex in bathrooms by the conventional culture method. In the present study, we aimed to directly detect M. avium organisms in the environment using loop-mediated isothermal amplification (LAMP), and to demonstrate the efficacy of LAMP by comparing the results with those obtained by culture. Our data showed that LAMP analysis has detection limits of 100 fg DNA/reaction for M. avium. Using an FTA(®) elute card, DNA templates were extracted from environmental samples from bathrooms in the residences of 29 patients with pulmonary M. avium disease. Of the 162 environmental samples examined, 143 (88%) showed identical results by both methods; 20 (12%) and 123 (76%) samples were positive and negative, respectively, for M. avium. Of the remaining 19 samples (12%), seven (5%) and 12 (7%) samples were positive by the LAMP and culture methods, respectively. All samples that contained over 20 colony forming units/primary isolation plate, as measured by the culture method, were also positive by the LAMP method. Our data demonstrate that the combination of the FTA elute card and LAMP can facilitate prompt detection of M. avium in the environment.

Evaluation of four novel isothermal amplification assays towards simple and rapid genotyping of chloroquine resistant Plasmodium falciparum.

Science.gov (United States)

Chahar, Madhvi; Anvikar, Anup; Dixit, Rajnikant; Valecha, Neena

2018-07-01

Loop mediated isothermal amplification (LAMP) assay is sensitive, prompt, high throughput and field deployable technique for nucleic acid amplification under isothermal conditions. In this study, we have developed and optimized four different visualization methods of loop-mediated isothermal amplification (LAMP) assay to detect Pfcrt K76T mutants of P. falciparum and compared their important features for one-pot in-field applications. Even though all the four tested LAMP methods could successfully detect K76T mutants of P. falciparum, however considering the time, safety, sensitivity, cost and simplicity, the malachite green and HNB based methods were found more efficient. Among four different visual dyes uses to detect LAMP products accurately, hydroxynaphthol blue and malachite green could produce long stable color change and brightness in a close tube-based approach to prevent cross-contamination risk. Our results indicated that the LAMP offers an interesting novel and convenient best method for the rapid, sensitive, cost-effective, and fairly user friendly tool for detection of K76T mutants of P. falciparum and therefore presents an alternative to PCR-based assays. Based on our comparative analysis, better field based LAMP visualization method can be chosen easily for the monitoring of other important drug targets (Kelch13 propeller region). Copyright © 2018 Elsevier Inc. All rights reserved.

Vitrification and Devitrification of Rigid Amorphous Fraction of PET during Quasi-isothermal Cooling and Heating

Science.gov (United States)

Cebe, Peggy; Chen, Huipeng

2009-03-01

Poly(ethylene terephthalate), PET, was studied by quasi-isothermal (QI) Temperature Modulated Differential Scanning Calorimetry (TMDSC). For the first time, both the temperature dependent crystalline fraction and rigid amorphous fraction (RAF) were quantitatively analyzed during QI cooling and reheating. Specific reversing heat capacity measurements show that most RAF vitrifies step by step during QI cooling after completion of crystallization. Upon subsequent QI reheating, the RAF devitrifies also step by step and only a small RAF of 0.04 remains at 470K, while melting starts above 473K. To obtain the exact temperature of the start of melting, heat capacity measurements were made using subsequent standard DSC heating, after QI cooling. By combining this method with the QI results, the temperature dependent phase fractions were obtained during standard DSC heating. We conclude that RAF completely devitrifies before the temperature reaches the crystal melting endotherm under the conditions used in this work.

ANALYTICAL SOLUTIONS OF SINGULAR ISOTHERMAL QUADRUPOLE LENS

International Nuclear Information System (INIS)

Chu Zhe; Lin, W. P.; Yang Xiaofeng

2013-01-01

Using an analytical method, we study the singular isothermal quadrupole (SIQ) lens system, which is the simplest lens model that can produce four images. In this case, the radial mass distribution is in accord with the profile of the singular isothermal sphere lens, and the tangential distribution is given by adding a quadrupole on the monopole component. The basic properties of the SIQ lens have been studied in this Letter, including the deflection potential, deflection angle, magnification, critical curve, caustic, pseudo-caustic, and transition locus. Analytical solutions of the image positions and magnifications for the source on axes are derived. We find that naked cusps will appear when the relative intensity k of quadrupole to monopole is larger than 0.6. According to the magnification invariant theory of the SIQ lens, the sum of the signed magnifications of the four images should be equal to unity, as found by Dalal. However, if a source lies in the naked cusp, the summed magnification of the left three images is smaller than the invariant 1. With this simple lens system, we study the situations where a point source infinitely approaches a cusp or a fold. The sum of the magnifications of the cusp image triplet is usually not equal to 0, and it is usually positive for major cusps while negative for minor cusps. Similarly, the sum of magnifications of the fold image pair is usually not equal to 0 either. Nevertheless, the cusp and fold relations are still equal to 0 in that the sum values are divided by infinite absolute magnifications by definition.

Solution of weakly compressible isothermal flow in landfill gas collection networks

Science.gov (United States)

Nec, Y.; Huculak, G.

2017-12-01

Pipe networks collecting gas in sanitary landfills operate under the regime of a weakly compressible isothermal flow of ideal gas. The effect of compressibility has been traditionally neglected in this application in favour of simplicity, thereby creating a conceptual incongruity between the flow equations and thermodynamic equation of state. Here the flow is solved by generalisation of the classic Darcy-Weisbach equation for an incompressible steady flow in a pipe to an ordinary differential equation, permitting continuous variation of density, viscosity and related fluid parameters, as well as head loss or gain due to gravity, in isothermal flow. The differential equation is solved analytically in the case of ideal gas for a single edge in the network. Thereafter the solution is used in an algorithm developed to construct the flow equations automatically for a network characterised by an incidence matrix, and determine pressure distribution, flow rates and all associated parameters therein.

Isothermal recovery rates in shape memory polyurethanes

International Nuclear Information System (INIS)

Azra, Charly; Plummer, Christopher J G; Månson, Jan-Anders E

2011-01-01

This work compares the time dependence of isothermal shape recovery in thermoset and thermoplastic shape memory polyurethanes (SMPUs) with comparable glass transition temperatures. In each case, tensile tests have been used to quantify the influence of various thermo-mechanical programming parameters (deformation temperature, recovery temperature, and stress and storage times following the deformation step) on strain recovery under zero load (free recovery) and stress recovery under fixed strain (constrained recovery). It is shown that the duration of the recovery event may be tuned over several decades of time with an appropriate choice of programming parameters, but that there is a trade-off between the rate of shape recovery and the recoverable stress level. The results are discussed in terms of the thermal characteristics of the SMPUs in the corresponding temperature range as characterized by modulated differential scanning calorimetry and dynamic mechanical analysis, with the emphasis on the role of the effective width of the glass transition temperature and the stability of the network that gives rise to the shape memory effect. (fast track communication)

Isothermal oxidation behavior of ternary Zr-Nb-Y alloys at high temperature

Energy Technology Data Exchange (ETDEWEB)

Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia); Soepriyanto, Syoni; Basuki, Eddy Agus [Metallurgy Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wiryolukito, Slameto [Materials Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24

The effect of yttrium content on isothermal oxidation behavior of Zr-2,5%Nb-0,5%Y, Zr-2,5%Nb-1%Y Zr-2,5%Nb-1,5%Y alloy at high temperature has been studied. High temperature oxidation carried out at tube furnace in air at 600,700 and 800°C for 1 hour. Optical microscope is used for microstructure characterization of the alloy. Oxidized and un oxidized specimen was characterized by x-ray diffraction. In this study, kinetic oxidation of Zr-2,5%Nb with different Y content at high temperature has also been studied. Characterization by optical microscope showed that microstructure of Zr-Nb-Y alloys relatively unchanged and showed equiaxed microstructure. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO2 while unoxidised alloy showed two phase α and β phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate.

Loop mediated isothermal amplification: An innovative gene amplification technique for animal diseases

Directory of Open Access Journals (Sweden)

Pravas Ranjan Sahoo

2016-05-01

Full Text Available India being a developing country mainly depends on livestock sector for its economy. However, nowadays, there is emergence and reemergence of more transboundary animal diseases. The existing diagnostic techniques are not so quick and with less specificity. To reduce the economy loss, there should be a development of rapid, reliable, robust diagnostic technique, which can work with high degree of sensitivity and specificity. Loop mediated isothermal amplification assay is a rapid gene amplification technique that amplifies nucleic acid under an isothermal condition with a set of designed primers spanning eight distinct sequences of the target. This assay can be used as an emerging powerful, innovative gene amplification diagnostic tool against various pathogens of livestock diseases. This review is to highlight the basic concept and methodology of this assay in livestock disease.

Loop mediated isothermal amplification: An innovative gene amplification technique for animal diseases.

Science.gov (United States)

Sahoo, Pravas Ranjan; Sethy, Kamadev; Mohapatra, Swagat; Panda, Debasis

2016-05-01

India being a developing country mainly depends on livestock sector for its economy. However, nowadays, there is emergence and reemergence of more transboundary animal diseases. The existing diagnostic techniques are not so quick and with less specificity. To reduce the economy loss, there should be a development of rapid, reliable, robust diagnostic technique, which can work with high degree of sensitivity and specificity. Loop mediated isothermal amplification assay is a rapid gene amplification technique that amplifies nucleic acid under an isothermal condition with a set of designed primers spanning eight distinct sequences of the target. This assay can be used as an emerging powerful, innovative gene amplification diagnostic tool against various pathogens of livestock diseases. This review is to highlight the basic concept and methodology of this assay in livestock disease.

Partial-Isothermally-Treated Low Alloy Ultrahigh Strength Steel with Martensitic/Bainitic Microstructure

Science.gov (United States)

Luo, Quanshun; Kitchen, Matthew; Patel, Vinay; Filleul, Martin; Owens, Dave

We introduce a new strengthening heat treatment of a Ni-Cr-Mo-V alloyed spring steel by partial isothermal salt-bath and subsequent air-cooling and tempering. Detailed isothermal treatments were made at temperatures below or above the Ms point (230°C). The salt bath time was controlled between 10 and 80 minutes. Through the new treatment, the candidate steel developed ultrahigh tensile strength 2,100 MPa, yield strength 1,800 MPa, elongation 8-10 %, hardness 580-710 HV, and V-notch Charpy toughness 10-12 J. Optical and electron microscopic observations and X-ray diffraction revealed multi-phase microstructures of bainitic/martensitic ferrites, fine carbide precipitates and retained austenite. Carbon partitioning during the bainitic/martensitic transformation was investigated for its remarkable influence on the strengthening mechanism.

Application of isothermal calorimetry and uv spectroscopy for stability monitoring of pentaerythritol tetranitrate

International Nuclear Information System (INIS)

Dosser, L.R.; Pickard, J.M.

1992-01-01

Thermal stabilities for a series of pentaerythritol-tetranitrate (PETN) samples with variable surf ace areas were monitored by isothermal calorimetry and UV spectroscopy over the temperature range of 363 to 408 K. Isothermal induction times measured with constant volume calorimetry under an air atmosphere and No evolution rates monitored by UV absorbance at 213 nm under vacuum correlated with the PETN surface area at temperatures equal to or exceeding 383 K. Rate data measured at 383 K are in accord with predictions based on detailed kinetic modeling. Below 383 K, NO evolution data suggested that additional geometric factors may be significant in controlling PETN stability. Mechanisms for influencing surface area upon the rate-determining step are addressed

Experimental Adsorption Isotherm of Methane onto Activated Carbon at Sub- and Supercritical Temperatures

KAUST Repository

Rahman, Kazi Afzalur

2010-11-11

This paper presents the experimentally measured adsorption isotherm data for methane onto the pitch-based activated carbon type Maxsorb III for temperatures ranging from (120 to 220) K and pressures up to 1.4 MPa. These data are useful to study adsorbed natural gas (ANG) storage systems when the low temperature natural gas regasified from the liquid phase is considered to charge in the storage chamber. Adsorption parameters were evaluated from the isotherm data using the Tóth and Dubinin-Astakhov models. The isosteric heat of adsorption, which is concentration- and temperature-dependent, is extracted from the data. The Henry\\'s law coefficients for the methane/Maxsorb III pairs are evaluated at various temperatures. © 2010 American Chemical Society.

Relativistic sonic geometry for isothermal accretion in the Kerr metric

Science.gov (United States)

Arif Shaikh, Md

2018-03-01

We linearly perturb advective isothermal transonic accretion onto rotating astrophysical black holes to study the emergence of the relativistic acoustic spacetime and to investigate how the salient features of this spacetime is influenced by the spin angular momentum of the black hole. We have perturbed three different quantities—the velocity potential, the mass accretion rate and the relativistic Bernoulli’s constant to show that the acoustic metric obtained for these three cases are the same up to a conformal factor. By constructing the required causal structures, it has been demonstrated that the acoustic black holes are formed at the transonic points of the flow and the acoustic white holes are formed at the shock location. The corresponding acoustic surface gravity has been computed in terms of the relevant accretion variables and the background metric elements. We have performed a linear stability analysis of the background stationary flow.

Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry

Science.gov (United States)

Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic proc...

Molecular relaxation behavior and isothermal crystallization above glass transition temperature of amorphous hesperetin.

Science.gov (United States)

Shete, Ganesh; Khomane, Kailas S; Bansal, Arvind Kumar

2014-01-01

The purpose of this paper was to investigate the relaxation behavior of amorphous hesperetin (HRN), using dielectric spectroscopy, and assessment of its crystallization kinetics above glass transition temperature (Tg ). Amorphous HRN exhibited both local (β-) and global (α-) relaxations. β-Relaxation was observed below Tg , whereas α-relaxation prominently emerged above Tg . β-Relaxation was found to be of Johari-Goldstein type and was correlated with α-process by coupling model. Secondly, isothermal crystallization experiments were performed at 363 K (Tg + 16.5 K), 373 K (Tg + 26.5 K), and 383 K (Tg + 36.5 K). The kinetics of crystallization, obtained from the normalized dielectric strength, was modeled using the Avrami model. Havriliak-Negami (HN) shape parameters, αHN and αHN .βHN , were analyzed during the course of crystallization to understand the dynamics of amorphous phase during the emergence of crystallites. HN shape parameters indicated that long range (α-like) were motions affected to a greater extent than short range (β-like) motions during isothermal crystallization studies at all temperature conditions. The variable behavior of α-like motions at different isothermal crystallization temperatures was attributed to evolving crystallites with time and increase in electrical conductivity with temperature. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Effect of bainitic isothermal transformation plus Q&P process on the microstructure and mechanical properties of 0.2C bainitic steel

Energy Technology Data Exchange (ETDEWEB)

Huang, Yuyin; Li, Qiangguo; Huang, Xuefei; Huang, Weigang, E-mail: huangwg56@163.com

2016-12-15

A novel bainitic isothermal transformation plus quenching and partitioning (B-QP) process was developed for a 0.2C-1.5Si-1.8Mn bainitic steel. The microstructure and mechanical properties of the steel treated by different heat treatment process were investigated. The results show that the B{sub 3}-QP (the subscript ‘3’ indicates the isothermal holding of 3 min for the bainitic transformation) samples exhibit a multiphase microstructure containing carbide-free bainite, martensite, film-like retained austenite. The microstructure is much finer than that of the Q&T samples with full martensite and the B{sub 30}-QP samples with a bainite microstructure. Although the Q&T sample has the highest tensile strength (1455 MPa), the ductility and the product of strength and elongation (PSE) are lower. In contrast, the B{sub 3}-QP and B{sub 30}-QP samples exhibit better ductility and higher PSE values of 26.3 GPa% and 28.2 GPa%, respectively. Furthermore, the B{sub 3}-QP sample exhibits maximum impact toughness value of 121 Jcm{sup −2}, which is about 20% and 55% higher than those of Q&T sample (101 J cm{sup −2}) and B{sub 30}-QP sample (78 J cm{sup −2}) respectively.

Determination of drying kinetics and sorption isotherm of black pepper (Piper Nigrum)

Science.gov (United States)

De Vera, Flordeliza C.; Atienza, Vanessa Bernadette B.; Capili, Jomicah B.; Sauli, Zaliman

2017-11-01

In the present study of food products, determination of the drying characteristics of black pepper using an oven is not yet completely established. This study aimed to determine the drying kinetics and sorption isotherm of black pepper using a convective oven at 30°C, 40°C and 50°C. The data gathered in this study were used to fit in selected mathematical models for drying kinetics and sorption isotherm. Among these models, the Midilli model (MR=0.5338exp(0.7273t-0.0551)+-0.0005t for 30°C, MR=0.5814exp(0.6293t-0.0764)+ -0.0008t for 40°C and MR=0.3187exp(1.1777t-0.0466)+ -0.0011t for 50°C) was the best fit to explain the moisture transfer in black pepper, while the GAB Model (m/0.1302=((0.1906)(0.7811)aw)/(1-(0.7811)aw)[1-(0.7811)aw+(0.1906)(0.7811)aw])) was for the equilibrium moisture content and water activity relationship. After evaluating the data, the drying characteristics of black pepper at 40°C yielded better results than 30°C and 50°C. XLSTAT and ANOVA Add-in of Microsoft Excel was the software used to compute for the necessary values in the assessment of the mathematical models for this study.

Single-experiment displacement assay for quantifying high-affinity binding by isothermal titration calorimetry.

Science.gov (United States)

Krainer, Georg; Keller, Sandro

2015-04-01

Isothermal titration calorimetry (ITC) is the gold standard for dissecting the thermodynamics of a biomolecular binding process within a single experiment. However, reliable determination of the dissociation constant (KD) from a single titration is typically limited to the range 100 μM>KD>1 nM. Interactions characterized by a lower KD can be assessed indirectly by so-called competition or displacement assays, provided that a suitable competitive ligand is available whose KD falls within the directly accessible window. However, this protocol is limited by the fact that it necessitates at least two titrations to characterize one high-affinity inhibitor, resulting in considerable consumption of both sample material and time. Here, we introduce a fast and efficient ITC displacement assay that allows for the simultaneous characterization of both a high-affinity ligand and a moderate-affinity ligand competing for the same binding site on a receptor within a single experiment. The protocol is based on a titration of the high-affinity ligand into a solution containing the moderate-affinity ligand bound to the receptor present in excess. The resulting biphasic binding isotherm enables accurate and precise determination of KD values and binding enthalpies (ΔH) of both ligands. We discuss the theoretical background underlying the approach, demonstrate its practical application to metal ion chelation, explore its potential and limitations with the aid of simulations and statistical analyses, and elaborate on potential applications to protein-inhibitor interactions. Copyright © 2014 Elsevier Inc. All rights reserved.

Sorption isotherms for oat flakes (Avena sativa L.

Directory of Open Access Journals (Sweden)

José Edgar Zapata M.

2014-04-01

Full Text Available Moisture sorption isotherms of oat flakes were determined at temperatures of 5, 25 and 37°C, using a gravimetric technique in an a w range of between 0.107 and 0.855. These curves were modeled using six equations commonly applied in food. The quality of the fit was assessed with the regression coefficient (r² and the mean relative percentage error (MRPE. The best fit were obtained with the Caurie model with r² of 0.996, 0.901 and 0.870, and MRPE of 7.190, 17.878 and 16.206, at 5, 25 and 37°C, respectively. The equilibrium moisture presented a dependence on temperature in the studied a w range, as did the security moisture (X S. These results suggest that the recommended storage conditions of oat flakes include: a relative air humidity of 50% between 5 and 25°C and of 38% up to 37°C.

One-step isothermal detection of multiple KRAS mutations by forming SNP specific hairpins on a gold nanoshell.

Science.gov (United States)

Chung, Chan Ho; Kim, Joong Hyun

2018-04-24

We developed a one-step isothermal method for typing multiple KRAS mutations using a designed set of primers to form a hairpin on a gold nanoshell upon being ligated by a SNP specific DNA ligase after binding of targets. As a result, we could detect as low as 20 attomoles of KRAS mutations within 1 h.

Isotherms of ion exchange on titanates of alkaline metals

International Nuclear Information System (INIS)

Fillina, L.P.; Belinskaya, F.A.

1986-01-01

Present article is devoted to isotherms of ion exchange on titanates of alkaline metals. Therefore, finely dispersed hydrated titanates of alkaline metals (lithium, sodium, potassium) with ion exchange properties are obtained by means of alkaline hydrolysis of titanium chloride at high ph rates. Sorption of cations from salts solution of Li 2 SO 4 , NaNO 3 , Ca(NO 3 ) 2 , AgNO 3 by titanates is studied.

Isobaric-isothermal Monte Carlo simulations from first principles: Application to liquid water at ambient conditions

Energy Technology Data Exchange (ETDEWEB)

McGrath, M; Siepmann, J I; Kuo, I W; Mundy, C J; VandeVondele, J; Hutter, J; Mohamed, F; Krack, M

2004-12-02

A series of first principles Monte Carlo simulations in the isobaric-isothermal ensemble were carried out for liquid water at ambient conditions (T = 298 K and p = 1 atm). The Becke-Lee-Yang-Parr (BLYP) exchange and correlation energy functionals and norm-conserving Goedecker-Teter-Hutter (GTH) pseudopotentials were employed with the CP2K simulation package to examine systems consisting of 64 water molecules. The fluctuations in the system volume encountered in simulations in the isobaric-isothermal ensemble requires a reconsideration of the suitability of the typical charge density cutoff and the regular grid generation method previously used for the computation of the electrostatic energy in first principles simulations in the microcanonical or canonical ensembles. In particular, it is noted that a much higher cutoff is needed and that the most computationally efficient method of creating grids can result in poor simulations. Analysis of the simulation trajectories using a very large charge density cutoff at 1200 Ry and four different grid generation methods point to a substantially underestimated liquid density of about 0.85 g/cm{sup 3} resulting in a somewhat understructured liquid (with a value of about 2.7 for the height of the first peak in the oxygen/oxygen radial distribution function) for BLYP-GTH water at ambient conditions.

Modelling of the isothermal replication of surface microstructures in polymer melts

DEFF Research Database (Denmark)

Rasmussen, Henrik Koblitz; Eriksson, Torbjörn Gerhard

2005-01-01

boundary condition. This allows an investigation of the effect of the rheological properties of the polymer melt on the ability of the material to fill small structures in a mould surface. Series of isothermal compression moulding experiments were performed with a polycarbonate (PC) and a polystyrene (PS...

Investigation of kinetics and absorption isotherm models for hydroponic phytoremediation of waters contaminated with sulfate.

Science.gov (United States)

Saber, Ali; Tafazzoli, Milad; Mortazavian, Soroosh; James, David E

2018-02-01

Two common wetland plants, Pampas Grass (Cortaderia selloana) and Lucky Bamboo (Dracaena sanderiana), were used in hydroponic cultivation systems for the treatment of simulated high-sulfate wastewaters. Plants in initial experiments at pH 7.0 removed sulfate more efficiently compared to the same experimental conditions at pH 6.0. Results at sulfate concentrations of 50, 200, 300, 600, 900, 1200, 1500 and 3000 mg/L during three consecutive 7-day treatment periods with 1-day rest intervals, showed decreasing trends of both removal efficiencies and uptake rates with increasing sulfate concentrations from the first to the second to the third 7-day treatment periods. Removed sulfate masses per unit dry plant mass, calculated after 23 days, showed highest removal capacity at 600 mg/L sulfate for both plants. A Langmuir-type isotherm best described sulfate uptake capacity of both plants. Kinetic studies showed that compared to pseudo first-order kinetics, pseudo-second order kinetic models slightly better described sulfate uptake rates by both plants. The Elovich kinetic model showed faster rates of attaining equilibrium at low sulfate concentrations for both plants. The dimensionless Elovich model showed that about 80% of sulfate uptake occurred during the first four days' contact time. Application of three 4-day contact times with 2-day rest intervals at high sulfate concentrations resulted in slightly higher uptakes compared to three 7-day contact times with 1-day rest intervals, indicating that pilot-plant scale treatment systems could be sized with shorter contact times and longer rest-intervals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solution of weakly compressible isothermal flow in landfill gas collection networks

Energy Technology Data Exchange (ETDEWEB)

Nec, Y [Thompson Rivers University, Kamloops, British Columbia (Canada); Huculak, G, E-mail: cranberryana@gmail.com, E-mail: greg@gnhconsulting.ca [GNH Consulting, Delta, British Columbia (Canada)

2017-12-15

Pipe networks collecting gas in sanitary landfills operate under the regime of a weakly compressible isothermal flow of ideal gas. The effect of compressibility has been traditionally neglected in this application in favour of simplicity, thereby creating a conceptual incongruity between the flow equations and thermodynamic equation of state. Here the flow is solved by generalisation of the classic Darcy–Weisbach equation for an incompressible steady flow in a pipe to an ordinary differential equation, permitting continuous variation of density, viscosity and related fluid parameters, as well as head loss or gain due to gravity, in isothermal flow. The differential equation is solved analytically in the case of ideal gas for a single edge in the network. Thereafter the solution is used in an algorithm developed to construct the flow equations automatically for a network characterised by an incidence matrix, and determine pressure distribution, flow rates and all associated parameters therein. (paper)

Solution of weakly compressible isothermal flow in landfill gas collection networks

International Nuclear Information System (INIS)

Nec, Y; Huculak, G

2017-01-01

Pipe networks collecting gas in sanitary landfills operate under the regime of a weakly compressible isothermal flow of ideal gas. The effect of compressibility has been traditionally neglected in this application in favour of simplicity, thereby creating a conceptual incongruity between the flow equations and thermodynamic equation of state. Here the flow is solved by generalisation of the classic Darcy–Weisbach equation for an incompressible steady flow in a pipe to an ordinary differential equation, permitting continuous variation of density, viscosity and related fluid parameters, as well as head loss or gain due to gravity, in isothermal flow. The differential equation is solved analytically in the case of ideal gas for a single edge in the network. Thereafter the solution is used in an algorithm developed to construct the flow equations automatically for a network characterised by an incidence matrix, and determine pressure distribution, flow rates and all associated parameters therein. (paper)

Detection of feline Coronavirus in effusions of cats with and without feline infectious peritonitis using loop-mediated isothermal amplification.

Science.gov (United States)

Günther, Sonja; Felten, Sandra; Wess, Gerhard; Hartmann, Katrin; Weber, Karin

2018-06-01

Feline infectious peritonitis (FIP) is a fatal disease in cats worldwide. The aim of this study was to test two commercially available reaction mixtures in a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay to detect feline Coronavirus (FCoV) in body cavity effusions of cats with and without FIP, in order to minimize the time from sampling to obtaining results. RNA was extracted from body cavity effusion samples of 71 cats, including 34 samples from cats with a definitive diagnosis of FIP, and 37 samples of control cats with similar clinical signs but other confirmed diseases. Two reaction mixtures (Isothermal Mastermix, OptiGene Ltd.and PCRun™ Molecular Detection Mix, Biogal) were tested using the same primers, which were designed to bind to a conserved region of the FCoV membrane protein gene. Both assays were conducted under isothermal conditions (61 °C-62 °C). Using the Isothermal Mastermix of OptiGene Ltd., amplification times ranged from 4 and 39 min with a sensitivity of 35.3% and a specificity of 94.6% for the reported sample group. Using the PCRun™ Molecular Detection Mix of Biogal, amplification times ranged from 18 to 77 min with a sensitivity of 58.8% and a specificity of 97.3%. Although the RT-LAMP assay is less sensitive than real time reverse transcription PCR (RT-PCR), it can be performed without the need of expensive equipment and with less hands-on time. Further modifications of primers might lead to a suitable in-house test and accelerate the diagnosis of FIP. Copyright © 2018 Elsevier B.V. All rights reserved.

Non-isothermal compositional gas flow during carbon dioxide storage and enhanced gas recovery

DEFF Research Database (Denmark)

Singh, Ashok; Böettcher, N.; Wang, W.

2011-01-01

In this work we present the conceptual modeling and the numerical scheme for carbon dioxide storage into nearly depleted gas reservoirs for enhanced gas recovery reasons. For this we develop non-isothermal compositional gas flow model. We used a combined monolithic / staggered coupling scheme...... to solve mass balance equation for the gaseous mixture with heat and fractional mass transport equations. Temperature change resulting from fluid expansion and viscous heat dissipation is included in heat transport in addition to advection and conduction. We have used a modified version of the Peng...

Moisture ingress into electronics enclosures under isothermal conditions

DEFF Research Database (Denmark)

Staliulionis, Zygimantas; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

2016-01-01

loads are still not understood well by design engineers, therefore this field has become one of the bottlenecks in the electronics system design. The objective of this paper is to model moisture ingress into an electronics enclosure under isothermal conditions. The moisture diffusion model is based......The number of electronics used in outdoor environment is constantly growing. The humidity causes about 19 % of all electronics failures and, especially, moisture increases these problems due to the ongoing process of miniaturization and lower power consumption of electronic components. Moisture...

Adsorption Isotherms of Phenol and 4-Chlorophenol on Petroleum Asphaltenes Adsorption du phénol et du 4-chlorophénol sur les asphaltènes pétroliers

Directory of Open Access Journals (Sweden)

Jaoui M.

2006-11-01

Full Text Available The adsorption isotherms for phenol and 4-chlorophenol from water onto asphaltenes flocculated in bulk and asphaltenes deposited on silica were established by frontal analysis chromatography at 293, 298, 303, and 308 K. The adsorption was more important with asphaltenes flocculated in bulk and corresponded to a Freundlich isotherm mechanism. The high adsorbed amount of phenols suggests possible migration of phenols through the loose asphaltene structure. Isotherms observed with the silica coated by asphaltenes showed that adsorption occurs in two stages corresponding probably to two different organizations of solute molecules at the surface. Les isothermes d'adsorption du phénol et du 4-chlorophénol en solution dans l'eau sur des asphaltènes floculés en masse et sur des asphaltènes déposés sur de la silice ont été déterminés par analyse chromatographique frontale à 293, 298, 303 et 308 K. L'adsorption sur des asphaltènes floculés en masse était la plus importante avec des isothermes correspondant à un mécanisme de Freundlich. La quantité élevée de phénols adsorbés suggère une migration possible des molécules du phénol à travers la structure peu compacte des asphaltènes. Les isothermes observés dans le cas de silice tapissée d'asphaltènes ont montré que l'adsorption se produit en deux étapes correspondant probablement à deux organisations différentes des molécules de soluté à la surface.

Construction and optimization of an efficient breathing-based isothermal emulsion amplification method

Energy Technology Data Exchange (ETDEWEB)

Shen, Yanting, E-mail: shenyanting798@126.com [Research Center for Learning Science, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); State Key Laboratory of Bioelectronics, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); Tian, Fei, E-mail: 642807827@qq.com [Research Center for Learning Science, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); Tu, Jing, E-mail: jtu@seu.edu.cn [State Key Laboratory of Bioelectronics, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); Li, Rui, E-mail: lirui901113@163.com [Research Center for Learning Science, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); Chen, Zhenzhu, E-mail: zzchen_seu@163.com [Research Center for Learning Science, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); Bai, Yunfei, E-mail: whitecf@seu.edu.cn [State Key Laboratory of Bioelectronics, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); Ge, Qinyu, E-mail: geqinyu@seu.edu.cn [State Key Laboratory of Bioelectronics, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China); Lu, Zuhong, E-mail: zhlu@seu.edu.cn [State Key Laboratory of Bioelectronics, Southeast University, Sipailou Road no. 2, Nanjing, Jiangsu Province 210096 (China)

2017-06-22

The reaction temperature is one of the main factors that affect the stability of emulsion PCR (emPCR). Focusing on this point, we applied the “DNA breathing” mechanism in BEAMing (Bead, Emulsion, Amplification, and Magnetic) and proposed a more stable emulsion amplification method. Compared to the conventional emPCR, this method provided excellent results. Firstly, more stable emulsion system resulted in higher percentage of single-molecular amplifications (73.17%). Secondly, an ordinary temperature-controlling device was enough. Our outcome showed that the reaction temperature of this method was not strict so that the ordinary temperature-controlling device was enough for it (the heat block sets vs. the PCR instrument: 13.140 ± 0.110 vs. 13.008 ± 0.039, P = 0.120). Thirdly, the single-biotinylated emP{sub 1} coated streptavidin beads were stable enough to be used for this method (the control temperature vs. the reaction temperature: 2967.91 ± 409.045 vs. 3026.22 ± 442.129, P = 0.334), which could replace the double-biotinylated emP{sub 1} coated beads and was benefit for saving cost. In conclusion, the method presented here with stable emulsion system, simplified temperature-controlling device, and decreased investment would be a highly streamlined and inexpensive option for future single-molecular amplification based researches. - Highlights: • A breathing-based isothermal emulsion amplification (BIEA) method was developed. • BIEA showed excellent properties compared with conventional amplification method. • Terminal breathing of DNA duplex was firstly used in emulsion amplification.

Effect of Prior Athermal Martensite on the Isothermal Transformation Kinetics Below M s in a Low-C High-Si Steel

NARCIS (Netherlands)

Navarro-Lopez, A.; Sietsma, J.; Santofimia, M.J.

2015-01-01

Thermomechanical processing of Advanced Multiphase High Strength Steels often includes isothermal treatments around the martensite start temperature (M s). It has been reported that the presence of martensite formed prior to these isothermal treatments accelerates the kinetics of the subsequent

Experimental aspects of buoyancy correction in measuring reliable highpressure excess adsorption isotherms using the gravimetric method.

Science.gov (United States)

Nguyen, Huong Giang T; Horn, Jarod C; Thommes, Matthias; van Zee, Roger D; Espinal, Laura

2017-12-01

Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO 2 and supercritical N 2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

Panus tigrinus as a potential biomass source for Reactive Blue decolorization: Isotherm and kinetic study

Directory of Open Access Journals (Sweden)

Monawar Munjid Mustafa

2017-03-01

Conclusion: The biosorption process provided vital information on the process parameters required to obtain the optimum level of dye removal. The isotherm study indicated the homogeneous distribution of active sites on the biomass surface, and the kinetic study suggested that chemisorption is the rate-limiting step that controlled the biosorption process. According to the obtained results, P. tigrinus biomass can be used effectively to decolorize textile dyes and tackle the pollution problems in the environment.

Loop-Mediated Isothermal Amplification Targeting Actin DNA of Trichomonas vaginalis.

Science.gov (United States)

Goo, Youn-Kyoung; Shin, Won-Sik; Yang, Hye-Won; Joo, So-Young; Song, Su-Min; Ryu, Jae-Sook; Kong, Hyun-Hee; Lee, Won-Ki; Chung, Dong-Il; Hong, Yeonchul

2016-06-01

Trichomoniasis caused by Trichomonas vaginalis is a common sexually transmitted disease. Its association with several health problems, including preterm birth, pelvic inflammatory disease, cervical cancer, and transmission of human immunodeficiency virus, emphasizes the importance of improved access to early and accurate detection of T. vaginalis. In this study, a rapid and efficient loop-mediated isothermal amplification-based method for the detection of T. vaginalis was developed and validated, using vaginal swab specimens from subjects suspected to have trichomoniasis. The LAMP assay targeting the actin gene was highly sensitive with detection limits of 1 trichomonad and 1 pg of T. vaginalis DNA per reaction, and specifically amplified the target gene only from T. vaginalis. Validation of this assay showed that it had the highest sensitivity and better agreement with PCR (used as the gold standard) compared to microscopy and multiplex PCR. This study showed that the LAMP assay, targeting the actin gene, could be used to diagnose early infections of T. vaginalis. Thus, we have provided an alternative molecular diagnostic tool and a point-of-care test that may help to prevent trichomoniasis transmission and associated complications.

Comparing the Caputo, Caputo-Fabrizio and Atangana-Baleanu derivative with fractional order: Fractional cubic isothermal auto-catalytic chemical system

Science.gov (United States)

Saad, K. M.

2018-03-01

In this work we extend the standard model for a cubic isothermal auto-catalytic chemical system (CIACS) to a new model of a fractional cubic isothermal auto-catalytic chemical system (FCIACS) based on Caputo (C), Caputo-Fabrizio (CF) and Atangana-Baleanu in the Liouville-Caputo sense (ABC) fractional time derivatives, respectively. We present approximate solutions for these extended models using the q -homotopy analysis transform method ( q -HATM). We solve the FCIACS with the C derivative and compare our results with those obtained using the CF and ABC derivatives. The ranges of convergence of the solutions are found and the optimal values of h , the auxiliary parameter, are derived. Finally, these solutions are compared with numerical solutions of the various models obtained using finite differences and excellent agreement is found.

Critical isothermal temperature and optimum mechanical behaviour of high Si-containing bainitic steels

International Nuclear Information System (INIS)

Misra, A.; Sharma, S.; Sangal, S.; Upadhyaya, A.; Mondal, K.

2012-01-01

The redistribution of carbon during partitioning between retained austenite and bainitic ferrite decides the stability of the retained austenite. The martensitic start temperature (M S ) based on the carbon enriched retained austenite is observed to be the deciding factor for the volume fraction of the constituent phases obtained on isothermal bainitic transformation. The volume fraction of the phases is also calculated on the basis of metastable equi-free energy (T 0 ) curve. A good agreement is found between experimentally and theoretically calculated fractions of the phases. The isothermal holding temperature and time, the fraction of phases based on initial carbon content of the steel and M S temperatures have a close relation with the optimum mechanical properties of bainitic steels.

Critical isothermal temperature and optimum mechanical behaviour of high Si-containing bainitic steels

Energy Technology Data Exchange (ETDEWEB)

Misra, A.; Sharma, S.; Sangal, S.; Upadhyaya, A. [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Mondal, K., E-mail: kallol@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India)

2012-12-15

The redistribution of carbon during partitioning between retained austenite and bainitic ferrite decides the stability of the retained austenite. The martensitic start temperature (M{sub S}) based on the carbon enriched retained austenite is observed to be the deciding factor for the volume fraction of the constituent phases obtained on isothermal bainitic transformation. The volume fraction of the phases is also calculated on the basis of metastable equi-free energy (T{sub 0}) curve. A good agreement is found between experimentally and theoretically calculated fractions of the phases. The isothermal holding temperature and time, the fraction of phases based on initial carbon content of the steel and M{sub S} temperatures have a close relation with the optimum mechanical properties of bainitic steels.

A Sweet Spot for Molecular Diagnostics: Coupling Isothermal Amplification and Strand Exchange Circuits to Glucometers

Science.gov (United States)

Du, Yan; Hughes, Randall A.; Bhadra, Sanchita; Jiang, Yu Sherry; Ellington, Andrew D.; Li, Bingling

2015-06-01

Strand exchange nucleic acid circuitry can be used to transduce isothermal nucleic acid amplification products into signals that can be readable on an off-the-shelf glucometer. Loop-mediated isothermal amplification (LAMP) is limited by the accumulation of non-specific products, but nucleic acid circuitry can be used to probe and distinguish specific amplicons. By combining this high temperature isothermal amplification method with a thermostable invertase, we can directly transduce Middle-East respiratory syndrome coronavirus and Zaire Ebolavirus templates into glucose signals, with a sensitivity as low as 20-100 copies/μl, equating to atto-molar (or low zepto-mole). Virus from cell lysates and synthetic templates could be readily amplified and detected even in sputum or saliva. An OR gate that coordinately triggered on viral amplicons further guaranteed fail-safe virus detection. The method describes has potential for accelerating point-of-care applications, in that biological samples could be applied to a transducer that would then directly interface with an off-the-shelf, approved medical device.

Energy transfer in compressible magnetohydrodynamic turbulence for isothermal self-gravitating fluids

Science.gov (United States)

Banerjee, Supratik; Kritsuk, Alexei G.

2018-02-01

Three-dimensional, compressible, magnetohydrodynamic turbulence of an isothermal, self-gravitating fluid is analyzed using two-point statistics in the asymptotic limit of large Reynolds numbers (both kinetic and magnetic). Following an alternative formulation proposed by Banerjee and Galtier [Phys. Rev. E 93, 033120 (2016), 10.1103/PhysRevE.93.033120; J. Phys. A: Math. Theor. 50, 015501 (2017), 10.1088/1751-8113/50/1/015501], an exact relation has been derived for the total energy transfer. This approach results in a simpler relation expressed entirely in terms of mixed second-order structure functions. The kinetic, thermodynamic, magnetic, and gravitational contributions to the energy transfer rate can be easily separated in the present form. By construction, the new formalism includes such additional effects as global rotation, the Hall term in the induction equation, etc. The analysis shows that solid-body rotation cannot alter the energy flux rate of compressible turbulence. However, the contribution of a uniform background magnetic field to the flux is shown to be nontrivial unlike in the incompressible case. Finally, the compressible, turbulent energy flux rate does not vanish completely due to simple alignments, which leads to a zero turbulent energy flux rate in the incompressible case.

Precipitation model in microalloyed steels both isothermal and continuous cooling conditions

International Nuclear Information System (INIS)

Medina, S. F.; Quispe, A.; Gomez, M.

2015-01-01

Niobium and vanadium precipitates (nitrides and carbides) can inhibit the static recrystallization of austenite but this does not happen for Ti, which form nitrides at high temperatures. RPTT diagrams show the interaction between recrystallization and precipitation allowing study the strain induced precipitation kinetics and precipitate coarsening. Based on Dutta and Sellars expression for the start of strain-induced precipitation in microalloyed steels, a new model has been constructed which takes into account the influence of variables such as microalloying element percentages, strain, temperature, strain rate and grain size. Recrystallization- Precipitation-Time-Temperature (RPTT) diagrams have been plotted thanks to a new experimental study carried out by means of hot torsion tests on approximately twenty microalloyed steels with different Nb, V and Ti contents. Mathematical analysis of the results recommends the modification of some parameters such as the supersaturation ratio (ks) and constant B, which is no longer a constant but a function of ks. The expressions are now more consistent and predict the Precipitation-Time-Temperature (PTT) curves with remarkable accuracy. The model for strain-induced precipitation kinetics is completed by means of Avramis equation. Finally, the model constructed in isothermal testing conditions, it has been converted to continuous cooling conditions in order to apply it in hot rolling. (Author)

Gun Shows and Gun Violence: Fatally Flawed Study Yields Misleading Results

Science.gov (United States)

Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A.

2010-01-01

A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas” outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors’ prior research. The study should not be used as evidence in formulating gun policy. PMID:20724672

Development of a novel loop-mediated isothermal amplification (LAMP) assay for the detection of Salmonella ser. Enteritidis from egg products

Science.gov (United States)

Salmonella ser. Enteritidis is a major public health concern worldwide. Loop-mediated isothermal amplification (LAMP) is a novel simple, easy-to-operate detection technology that amplifies DNA with high speed, efficiency, and specificity under isothermal conditions. The objective of this study was t...

Equilibrium isotherm and kinetic studies for the simultaneous removal of phenol and cyanide by use of S. odorifera (MTCC 5700) immobilized on coconut shell activated carbon

Science.gov (United States)

Singh, Neetu; Balomajumder, Chandrajit

2017-10-01

In this study, simultaneous removal of phenol and cyanide by a microorganism S. odorifera (MTCC 5700) immobilized onto coconut shell activated carbon surface (CSAC) was studied in batch reactor from mono and binary component aqueous solution. Activated carbon was derived from coconut shell by chemical activation method. Ferric chloride (Fecl3), used as surface modification agents was applied to biomass. Optimum biosorption conditions were obtained as a function of biosorbent dosage, pH, temperature, contact time and initial phenol and cyanide concentration. To define the equilibrium isotherms, experimental data were analyzed by five mono component isotherm and six binary component isotherm models. The higher uptake capacity of phenol and cyanide onto CSAC biosorbent surface was 450.02 and 2.58 mg/g, respectively. Nonlinear regression analysis was used for determining the best fit model on the basis of error functions and also for calculating the parameters involved in kinetic and isotherm models. The kinetic study results revealed that Fractal-like mixed first second order model and Brouser-Weron-Sototlongo models for phenol and cyanide were capable to offer accurate explanation of biosorption kinetic. According to the experimental data results, CSAC with immobilization of bacterium S. odorifera (MTCC 5700) seems to be an alternative and effective biosorbent for the elimination of phenol and cyanide from binary component aqueous solution.

A novel approach for evaluating the performance of real time quantitative loop-mediated isothermal amplification-based methods.

Science.gov (United States)

Nixon, Gavin J; Svenstrup, Helle F; Donald, Carol E; Carder, Caroline; Stephenson, Judith M; Morris-Jones, Stephen; Huggett, Jim F; Foy, Carole A

2014-12-01

Molecular diagnostic measurements are currently underpinned by the polymerase chain reaction (PCR). There are also a number of alternative nucleic acid amplification technologies, which unlike PCR, work at a single temperature. These 'isothermal' methods, reportedly offer potential advantages over PCR such as simplicity, speed and resistance to inhibitors and could also be used for quantitative molecular analysis. However there are currently limited mechanisms to evaluate their quantitative performance, which would assist assay development and study comparisons. This study uses a sexually transmitted infection diagnostic model in combination with an adapted metric termed isothermal doubling time (IDT), akin to PCR efficiency, to compare quantitative PCR and quantitative loop-mediated isothermal amplification (qLAMP) assays, and to quantify the impact of matrix interference. The performance metric described here facilitates the comparison of qLAMP assays that could assist assay development and validation activities.

Loop-Mediated Isothermal Amplification Using a Lab-on-a-Disc Device with Thin-film Phase Change Material.

Science.gov (United States)

Ko, Junguk; Yoo, Jae-Chern

2018-03-05

The design and fabrication of temperature measurement systems that facilitate successful realization of DNA amplification using a lab-on-a-disc (LOD) device are a highly challenging task. The major challenge lies in the fact that such a system must be directly attached to a heating chamber in a way that enables the accurate measurement of temperature of the chamber while allowing the LOD to rotate. This paper presents a temperature control system for implementing isothermal amplification of DNA samples using an LOD device. The proposed system utilizes a thin-film phase change material and non-contact heating system to remotely measure the actual temperature of the chamber and, if required, rapidly heat it to the desired temperature. The results of the experiments performed in this study demonstrate that the proposed system provides an automated platform for molecular amplification and exhibits an operational performance comparable to that of traditional microcentrifuge tube-based isothermal amplification systems.

Freundlich and Langmuir adsorption isotherms and kinetics for the removal of Tartrazine from aqueous solutions using hen feathers

International Nuclear Information System (INIS)

Mittal, Alok; Kurup, Lisha; Mittal, Jyoti

2007-01-01

Tartrazine, a yellow menace, is widely being used in cosmetics, foodstuffs, medicines and textile. It is carcinogenic and also catalyzes allergic problems. In the present work the ability to remove Tartrazine from aqueous solutions has been studied using waste material-hen feathers, as adsorbent. Effects of pH, concentration of the dye, temperature and adsorbent dosage have been studied. Equilibrium isotherms for the adsorption of the dye were measured experimentally. Results were analyzed by the Freundlich and Langmuir equation at different temperatures and determined the characteristic parameters for each adsorption isotherm. The adsorption process has been found endothermic in nature and thermodynamic parameters, Gibb's free energy (ΔG o ), change in enthalpy (ΔH o ) and change in entropy (ΔS o ) have been calculated. The paper also includes results on the kinetic measurements of adsorption of the dye on hen feathers at different temperatures. By rate expression and treatment of data it has been established that the adsorption of Tartrazine over hen feathers follows a first-order kinetics and a film diffusion mechanism operates at all the temperatures

Freundlich and Langmuir adsorption isotherms and kinetics for the removal of Tartrazine from aqueous solutions using hen feathers.

Science.gov (United States)

Mittal, Alok; Kurup, Lisha; Mittal, Jyoti

2007-07-19

Tartrazine, a yellow menace, is widely being used in cosmetics, foodstuffs, medicines and textile. It is carcinogenic and also catalyzes allergic problems. In the present work the ability to remove Tartrazine from aqueous solutions has been studied using waste material-hen feathers, as adsorbent. Effects of pH, concentration of the dye, temperature and adsorbent dosage have been studied. Equilibrium isotherms for the adsorption of the dye were measured experimentally. Results were analyzed by the Freundlich and Langmuir equation at different temperatures and determined the characteristic parameters for each adsorption isotherm. The adsorption process has been found endothermic in nature and thermodynamic parameters, Gibb's free energy (DeltaG degrees), change in enthalpy (DeltaH degrees) and change in entropy (DeltaS degrees) have been calculated. The paper also includes results on the kinetic measurements of adsorption of the dye on hen feathers at different temperatures. By rate expression and treatment of data it has been established that the adsorption of Tartrazine over hen feathers follows a first-order kinetics and a film diffusion mechanism operates at all the temperatures.

Isothermal sinusoidal analysis of balanced compound Vuilleumier heat pumps

International Nuclear Information System (INIS)

Finkelstein, T.

1992-01-01

This paper reports on Vuilleumier heat pumps with balanced compounding which have been under investigation for about fifteen years but have not yet reached the stage of commercial utilization. Previously published analytical treatment based upon isothermal treatment of the variable-volume spaces resulted in closed form solution of considerable complexity of the coupled differential equations but applied only to free piston machines. In contrast, the procedure presented here is based on previously demonstrated sinusoidal excursions of the reciprocators. It is of the same order of accuracy, but much more simple and usable. It was found that there is only negligible difference between the results of the present and the previous approach. Additionally, the treatment presented here is applicable to kinematic machines, as well as to free piston machines. For the latter design, an equation for the natural frequency is also derived. Ideal proportions and practical expressions for the energy streams are derived. Gas forces are plotted versus displacement and it is shown that they are equivalent to a linear spring, which is of importance for the concept of a free-piston design

Diagnosis of brugian filariasis by loop-mediated isothermal amplification.

Directory of Open Access Journals (Sweden)

Catherine B Poole

Full Text Available In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis.

Non-isothermal modelling of the all-vanadium redox flow battery

International Nuclear Information System (INIS)

Al-Fetlawi, H.; Shah, A.A.; Walsh, F.C.

2009-01-01

An non-isothermal model for the all-vanadium redox flow battery (RFB) is presented. The two-dimensional model is based on a comprehensive description of mass, charge, energy and momentum transport and conservation, and is combined with a global kinetic model for reactions involving vanadium species. Heat is generated as a result of activation losses, electrochemical reaction and ohmic resistance. Numerical simulations demonstrate the effects of changes in the operating temperature on performance. It is shown that variations in the electrolyte flow rate and the magnitude of the applied current substantially alter the charge/discharge characteristics, the temperature rise and the distribution of temperature. The influence of heat losses on the charge/discharge behaviour and temperature distribution is investigated. Conditions for localised heating and membrane degradation are discussed.

Use of isothermal titration calorimetry to study the interaction of short-chain alcohols with lipid membranes

DEFF Research Database (Denmark)

Trandum, Christa; Westh-Andersen, Peter; Jørgensen, Kent

1999-01-01

of short-chain alcohols on Lipid bilayers. isothermal titration calorimetry (ITC) has been used to determine the energy involved in the association of the alcohols with lipid bilayers. Pure unilamellar DMPC liposomes and DMPC liposomes incorporated with different amounts of cholesterol, sphingomyelin...... dependent on the lipid bilayer composition. In the presence of high concentrations of cholesterol, the binding enthalpy of ethanol is decreased, whereas the presence of ceramides enhances the enthalpic response of the lipid bilayer to ethanol. Isothermal titration calorimetry offers a new methodology...

A study of sorption mechanism onto cement hydrates by isotherm measurements

International Nuclear Information System (INIS)

Sugiyama, Daisuke; Fujita, Tomonari

2003-01-01

In the concept for TRU waste disposal in Japan, cement is a potential waste packaging and backfilling material and is expected to provide chemical containment. In particular, the sorption of radionuclides onto cement material, which controls the aqueous concentrations of elements in the porewater, is a very important parameter when considering the release of radionuclides from the near field of a repository. Many safety assessment calculations currently assume radionuclide retardation as linear sorption equilibrium and describe it with a distribution ratio (R d value). In this study, the sorption mechanism is discussed by measuring the sorption isotherm of caesium, strontium and thorium onto Ordinary Portland Cement (OPC) and Calcium Silicate Hydrate (C-S-H gel), to justify and support this assumption. In addition, the effect of competitive sorption between thorium and uranium and other groundwater ions is studied by examining sorption using a range of sodium chloride concentrations to simulate different groundwater ionic strengths. Based on the experimental results, we have showed that: Caesium and strontium sorb by substitution for Ca in C-S-H phases and the presence of some calcium sites with different ion-exchange log K values is suggested; Thorium would be fixed in a surface co-precipitation to form a solubility-limiting phase. The results of sorption experiments are reasonably well modelled by the ion-exchange model for caesium and strontium and the surface co-precipitation model for thorium, respectively. (author)

Visual Detection of Potato leafroll virus by One-step Reverse Transcription Loop-Mediated Isothermal Amplification of DNA with Hydroxynaphthol Blue Dye

NARCIS (Netherlands)

Ahmadi, S.; Almasi, A.M.; Fatehi, F.; Struik, P.C.; Moradi, A.

2013-01-01

Loop-mediated isothermal amplification (LAMP) assay is a novel technique for amplifying DNA under constant temperature, with high specificity, sensitivity, rapidity and efficiency. We applied reverse transcription loop-mediated isothermal amplification (RT-LAMP) to visually detect Potato leafroll

Application of a molecular beacon based real-time isothermal amplification (MBRTIA) technology for simultaneous detection of Bacillus cereus and Staphylococcus aureus.

Science.gov (United States)

Mandappa, I M; Joglekar, Prasanna; Manonmani, H K

2015-07-01

A multiplex real-time isothermal amplification assay was developed using molecular beacons for the detection of Bacillus cereus and Staphylococcus aureus by targeting four important virulence genes. A correlation between targeting highly accessible DNA sequences and isothermal amplification based molecular beacon efficiency and sensitivity was demonstrated using phi(Φ)29 DNA polymerase at a constant isothermal temperature of 30 °C. It was very selective and consistently detected down to 10(1) copies of DNA. The specificity and sensitivity of this assay, when tested with pure culture were high, surpassing those of currently used PCR assays for the detection of these organisms. The molecular beacon based real-time isothermal amplification (MBRTIA) assay could be carried out entirely in 96 well plates or well strips, enabling a rapid and high-throughput detection of food borne pathogens.

Acquisition of sorption isotherms for modified woods by the use of dynamic vapour sorption instrumentation. Principles and Practice

DEFF Research Database (Denmark)

Engelund, Emil Tang; Klamer, Morten; Venås, Thomas Mark

2010-01-01

The complex wood-water relationship has been the topic of numerous studies. Sorption isotherms – in particular – have been derived for hundreds of wood species, their sap- and heartwood sections as well as for decayed, engineered and modified wood materials. However, the traditional methods...... for obtaining sorption isotherms are very time consuming. With new dynamic vapour sorption (DVS) instrumentation, the acquisition of data for constructing sorption isotherms is suddenly dramatically lowered. Where the traditional methods often required months, data can now be obtained in a matter of days...... depending on the number of data points required. The fast data acquisition makes DVS a useful tool in studying the sorption properties of wood, and especially in studying the effect of different modification treatments on these properties. This study includes an investigation of the sorption properties...

Transient non-isothermal model of a polymer electrolyte fuel cell

Energy Technology Data Exchange (ETDEWEB)

Shah, A.A. [Queen' s-RMC Fuel Cell Research Centre, 945 Princess Street, Kingston, Ont. K7L 5L9 (Canada); Kim, G.-S.; Harvey, D. [Ballard Power Systems, 4343 North Fraser Way, Burnaby, BC V5J 5J9 (Canada); Sui, P.C. [Institute for Integrated Energy Systems, University of Victoria, Victoria, BC V8W 3P6 (Canada)

2007-01-01

In this paper we present a one-dimensional transient model for the membrane electrode assembly of a polymer-electrolyte fuel cell. In earlier work we established a framework to describe the water balance in a steady-state, non-isothermal cathode model that explicitly included an agglomerate catalyst layer component. This paper extends that work in several directions, explicitly incorporating components of the anode, including a micro-porous layer, and accounting for electronic potential variations, gas convection and time dependance. The inclusion of temperature effects, which are vital to the correct description of condensation and evaporation, is new to transient modelling. Several examples of the modelling results are given in the form of potentiostatic sweeps and compared to experimental results. Excellent qualitative agreement is demonstrated, particularly in regard to the phenomenon of hysteresis, a manifestation of the sensitive response of the system to the presence of water. Results pertaining to pore size, contact angle and the presence of a micro-porous layer are presented and future work is discussed. (author)

Isothermal phase equilibria for the (HFC-32 + HFC-134a) mixed-gas hydrate system

International Nuclear Information System (INIS)

Miyauchi, Hiroshi; Yasuda, Kenjiro; Matsumoto, Yuuki; Hashimoto, Shunsuke; Sugahara, Takeshi; Ohgaki, Kazunari

2012-01-01

Highlights: ► Structural phase transition results in the heterogeneous azeotropic-like behaviour. ► HFC-134a molecules, in spite of an s-II former, occupy the large cages of s-I. ► Negative azeotropic-like behaviour becomes more remarkable at higher temperatures. - Abstract: Isothermal phase equilibria (pressure-composition relations in hydrate, gas, and aqueous phases) in the {difluoromethane (HFC-32) + 1,1,1,2-tetrafluoroethane (HFC-134a)} mixed-gas hydrate system were measured at the temperatures 274.15 K, 279.15 K, and 283.15 K. The heterogeneous azeotropic-like behaviour derived from the structural phase transition of (HFC-32 + HFC-134a) mixed-gas hydrates appears over the whole temperature range of the present study. In addition to the heterogeneous azeotropic-like behaviour, the isothermal phase equilibrium curves of the (HFC-32 + HFC-134a) mixed-gas hydrate system exhibit the negative homogeneous azeotropic-like behaviour at temperatures 279.15 K and 283.15 K. The negative azeotropic-like behaviour, which becomes more remarkable at higher temperatures, results in the lower equilibrium pressure of (HFC-32 + HFC-134a) mixed-gas hydrates than those of both simple HFC-32 and HFC-134a hydrates. Although the HFC-134a molecule forms the simple structure-II hydrate at the temperatures, the present findings reveal that HFC-134a molecules occupy a part of the large cages of the structure-I mixed-gas hydrate.

Phosphate sorption by three potential filter materials as assessed by isothermal titration calorimetry.

Science.gov (United States)

Lyngsie, Gry; Penn, Chad J; Hansen, Hans C B; Borggaard, Ole K

2014-10-01

Phosphorus eutrophication of lakes and streams, coming from drained farmlands, is a serious problem in areas with intensive agriculture. Installation of phosphate (P) sorbing filters at drain outlets may be a solution. The aim of this study was to improve the understanding of reactions involved in P sorption by three commercial P sorbing materials, i.e. Ca/Mg oxide-based Filtralite-P, Fe oxide-based CFH-12 and Limestone in two particle sizes (2-1 mm and 1-0.5 mm), by means of isothermal titration calorimetry (ITC), sorption isotherms, sequential extractions and SEM-EDS. The results indicate that P retention by CFH is due to surface complexation by rapid formation of strong Fe-P bonds. In contrast, retention of P by Filtralite-P and Limestone strongly depends on pH and time and is interpreted due to formation of calcium phosphate precipitate(s). Consequently, CFH can unambiguously be recommended as P retention filter material in drain outlets, whereas the use of Filtralite-P and Limestone has certain (serious) limitations. Thus, Filtralite-P has high capacity to retain P but only at alkaline pH (pH ≥ 10) and P retention by Limestone requires long-time contact and a high ratio between sorbent and sorbate. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid and Sensitive Isothermal Detection of Nucleic-acid Sequence by Multiple Cross Displacement Amplification.

Science.gov (United States)

Wang, Yi; Wang, Yan; Ma, Ai-Jing; Li, Dong-Xun; Luo, Li-Juan; Liu, Dong-Xin; Jin, Dong; Liu, Kai; Ye, Chang-Yun

2015-07-08

We have devised a novel amplification strategy based on isothermal strand-displacement polymerization reaction, which was termed multiple cross displacement amplification (MCDA). The approach employed a set of ten specially designed primers spanning ten distinct regions of target sequence and was preceded at a constant temperature (61-65 °C). At the assay temperature, the double-stranded DNAs were at dynamic reaction environment of primer-template hybrid, thus the high concentration of primers annealed to the template strands without a denaturing step to initiate the synthesis. For the subsequent isothermal amplification step, a series of primer binding and extension events yielded several single-stranded DNAs and single-stranded single stem-loop DNA structures. Then, these DNA products enabled the strand-displacement reaction to enter into the exponential amplification. Three mainstream methods, including colorimetric indicators, agarose gel electrophoresis and real-time turbidity, were selected for monitoring the MCDA reaction. Moreover, the practical application of the MCDA assay was successfully evaluated by detecting the target pathogen nucleic acid in pork samples, which offered advantages on quick results, modest equipment requirements, easiness in operation, and high specificity and sensitivity. Here we expounded the basic MCDA mechanism and also provided details on an alternative (Single-MCDA assay, S-MCDA) to MCDA technique.

Endpoint visual detection of three genetically modified rice events by loop-mediated isothermal amplification.

Science.gov (United States)

Chen, Xiaoyun; Wang, Xiaofu; Jin, Nuo; Zhou, Yu; Huang, Sainan; Miao, Qingmei; Zhu, Qing; Xu, Junfeng

2012-11-07

Genetically modified (GM) rice KMD1, TT51-1, and KF6 are three of the most well known transgenic Bt rice lines in China. A rapid and sensitive molecular assay for risk assessment of GM rice is needed. Polymerase chain reaction (PCR), currently the most common method for detecting genetically modified organisms, requires temperature cycling and relatively complex procedures. Here we developed a visual and rapid loop-mediated isothermal amplification (LAMP) method to amplify three GM rice event-specific junction sequences. Target DNA was amplified and visualized by two indicators (SYBR green or hydroxy naphthol blue [HNB]) within 60 min at an isothermal temperature of 63 °C. Different kinds of plants were selected to ensure the specificity of detection and the results of the non-target samples were negative, indicating that the primer sets for the three GM rice varieties had good levels of specificity. The sensitivity of LAMP, with detection limits at low concentration levels (0.01%−0.005% GM), was 10- to 100-fold greater than that of conventional PCR. Additionally, the LAMP assay coupled with an indicator (SYBR green or HNB) facilitated analysis. These findings revealed that the rapid detection method was suitable as a simple field-based test to determine the status of GM crops.

Endpoint Visual Detection of Three Genetically Modified Rice Events by Loop-Mediated Isothermal Amplification

Directory of Open Access Journals (Sweden)

Qing Zhu

2012-11-01

Full Text Available Genetically modified (GM rice KMD1, TT51-1, and KF6 are three of the most well known transgenic Bt rice lines in China. A rapid and sensitive molecular assay for risk assessment of GM rice is needed. Polymerase chain reaction (PCR, currently the most common method for detecting genetically modified organisms, requires temperature cycling and relatively complex procedures. Here we developed a visual and rapid loop-mediated isothermal amplification (LAMP method to amplify three GM rice event-specific junction sequences. Target DNA was amplified and visualized by two indicators (SYBR green or hydroxy naphthol blue [HNB] within 60 min at an isothermal temperature of 63 °C. Different kinds of plants were selected to ensure the specificity of detection and the results of the non-target samples were negative, indicating that the primer sets for the three GM rice varieties had good levels of specificity. The sensitivity of LAMP, with detection limits at low concentration levels (0.01%–0.005% GM, was 10- to 100-fold greater than that of conventional PCR. Additionally, the LAMP assay coupled with an indicator (SYBR green or HNB facilitated analysis. These findings revealed that the rapid detection method was suitable as a simple field-based test to determine the status of GM crops.

Functional entropy variables: A new methodology for deriving thermodynamically consistent algorithms for complex fluids, with particular reference to the isothermal Navier–Stokes–Korteweg equations

Energy Technology Data Exchange (ETDEWEB)

Liu, Ju, E-mail: jliu@ices.utexas.edu [Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th Street, 1 University Station C0200, Austin, TX 78712 (United States); Gomez, Hector [Department of Mathematical Methods, University of A Coruña, Campus de Elviña, s/n, 15192 A Coruña (Spain); Evans, John A.; Hughes, Thomas J.R. [Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th Street, 1 University Station C0200, Austin, TX 78712 (United States); Landis, Chad M. [Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, 210 East 24th Street, 1 University Station C0600, Austin, TX 78712 (United States)

2013-09-01

We propose a new methodology for the numerical solution of the isothermal Navier–Stokes–Korteweg equations. Our methodology is based on a semi-discrete Galerkin method invoking functional entropy variables, a generalization of classical entropy variables, and a new time integration scheme. We show that the resulting fully discrete scheme is unconditionally stable-in-energy, second-order time-accurate, and mass-conservative. We utilize isogeometric analysis for spatial discretization and verify the aforementioned properties by adopting the method of manufactured solutions and comparing coarse mesh solutions with overkill solutions. Various problems are simulated to show the capability of the method. Our methodology provides a means of constructing unconditionally stable numerical schemes for nonlinear non-convex hyperbolic systems of conservation laws.

Experimental aspects of buoyancy correction in measuring reliable high-pressure excess adsorption isotherms using the gravimetric method

Science.gov (United States)

Nguyen, Huong Giang T.; Horn, Jarod C.; Thommes, Matthias; van Zee, Roger D.; Espinal, Laura

2017-12-01

Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO2 and supercritical N2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

Development of a reverse transcriptase loop-mediated isothermal amplification (LAMP) assay for the sensitive detection of Leishmania parasites in clinical samples

NARCIS (Netherlands)

Adams, Emily R.; Schoone, Gerard J.; Ageed, Al Farazdag; El Safi, Sayda; Schallig, Henk D. F. H.

2010-01-01

Here we describe a generic, reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) assay, for the identification of Leishmania species from clinical samples. LAMP is an isothermal reaction recently developed as a point-of-care diagnostic tool. Primers were designed in the conserved

The 600 °C and 450 °C isothermal sections of the Zn–Fe–B system

Energy Technology Data Exchange (ETDEWEB)

Yin, Fucheng, E-mail: fuchengyin@xtu.edu.cn; Ruan, Xinglong; Zhao, Manxiu; Liu, Yongxiong; Li, Zhi

2013-07-15

Highlights: •The 600°C and 450°C isothermal sections of the Zn-Fe-B system are determined. •The solubility of Zn in Fe{sub 2}B and FeB at 600°C is 1.8 at.% and 2.5 at.%, respectively. •The solubility of Zn in Fe{sub 2}B and FeB at 450°C is 1.7 at.% and 2.1 at.%, respectively. •All Fe-Zn compounds can be in equilibrium with Fe{sub 2}B at 450°C. •Both FeB and Fe{sub 2}B are in equilibrium with the liquid phase at 600°C. -- Abstract: The isothermal sections of Zn–Fe–B ternary system at 600 °C and 450 °C have been determined experimentally using scanning electron microscopy, electron probe microanalysis and X-ray diffraction. Five three-phase regions exist in the isothermal section at 600 °C, seven three-phase regions exist at 450 °C. The experimental results indicate that B is almost insoluble in Fe–Zn compounds and α-Fe. The solubility of Zn in Fe{sub 2}B and FeB at 600 °C is 1.8 at.% and 2.5 at.%, respectively, and that at 450 °C is 1.7 at.% and 2.1 at.%, respectively. All Fe–Zn compounds can be in equilibrium with Fe{sub 2}B, the equilibrium between FeB and ζ prohibits the coexistence of Fe{sub 2}B and liquid at 450 °C. Both FeB and Fe{sub 2}B are in equilibrium with the liquid phase at 600 °C.

Volatilisation of ruthenium in vitrification. Isothermal calcination studies of 'Magnox' and thermal oxide simulates

International Nuclear Information System (INIS)

Cains, P.W.; Hay, D.A.

1982-12-01

Ru volatilities have been measured for the static, isothermal calcination of ''Magnox'' and Thermal Oxide HAL's (Highly Active Liquors) at temperatures up to 600 0 C. Model solutions containing Ru, HNO 3 , and nitrates of important individual cations have also been investigated. Experimental design was primarily based on the requirements of rotary calcination process development. The results have been interpreted in terms of a reaction model involving competition between the simple degradation of Ru(NO) complexes to RuO 2 and oxidative decomposition to volatile species (e.g. RuO 4 ). (author)

On the membrane approximation in isothermal film casting

Science.gov (United States)

Hagen, Thomas

2014-08-01

In this work, a one-dimensional model for isothermal film casting is studied. Film casting is an important engineering process to manufacture thin films and sheets from a highly viscous polymer melt. The model equations account for variations in film width and film thickness, and arise from thinness and kinematic assumptions for the free liquid film. The first aspect of our study is a rigorous discussion of the existence and uniqueness of stationary solutions. This objective is approached via the argument principle, exploiting the homotopy invariance of a family of analytic functions. As our second objective, we analyze the linearization of the governing equations about stationary solutions. It is shown that solutions for the associated boundary-initial value problem are given by a strongly continuous semigroup of bounded linear operators. To reach this result, we cast the relevant Cauchy problem in a more accessible form. These transformed equations allow us insight into the regularity of the semigroup, thus yielding the validity of the spectral mapping theorem for the semigroup and the spectrally determined growth property.

Kinetics, isothermal and thermodynamics studies of electrocoagulation removal of basic dye rhodamine B from aqueous solution using steel electrodes

Science.gov (United States)

Adeogun, Abideen Idowu; Balakrishnan, Ramesh Babu

2017-07-01

Electrocoagulation was used for the removal of basic dye rhodamine B from aqueous solution, and the process was carried out in a batch electrochemical cell with steel electrodes in monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process, were investigated. Equilibrium was attained after 10 min at 30 °C. Pseudo-first-order, pseudo-second-order, Elovich and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic adsorption process; pseudo-first-order and Avrami models best fitted the data. Experimental data were analysed using six model equations: Langmuir, Freudlinch, Redlich-Peterson, Temkin, Dubinin-Radushkevich and Sips isotherms and it was found that the data fitted well with Sips isotherm model. The study showed that the process depends on current density, temperature, pH and initial dye concentration. The calculated thermodynamics parameters (Δ G°, Δ H° and Δ S°) indicated that the process is spontaneous and endothermic in nature.

Pyrolysis kinetics investigation of Malaysian based biomass with non-isothermal thermogravimetric analysis (TGA)

International Nuclear Information System (INIS)

Seyed Shahabeddin Nehzati; Dayang Radiah Awang Biak; Wan Azlina Wan Abdul Karim Ghani; Mohd Amran Mohd Salleh

2010-01-01

Full text: Biomass is currently being used as a sustainable energy source. Otherwise the scarceness of fossil fuel sources and the demand for environmental responsibility force the industries to use biomass as an alternate source of energy. Pyrolysis is the first step of biomass conversion and well understanding of this process can develop the biomass conversion such as gasification, liquefaction, carbonization and combustion .TGA studies of Malaysian based biomass have been carried out. TGA studies provide important insight on the thermochemical behavior of specific solid waste. The results of non-isothermal thermogravimetric analysis of palm kernel shell, coconut shell and bagasse, carried out at heating rates of 10 degree Celsius/ min, 20 degree Celsius/ min and 50 degree Celsius/ min, to ramp the temperature from 30 to 1000 were analysed. The TGA studies were carried out in an inert atmosphere of nitrogen. Arrhenius parameters were estimated by 3 different models namely Kissinger model, three-pseudo component and DEAM model the estimated values and the models were compared. The results show that the three-pseudo component model has a good agreement with the experimental results, indicating that ligno celluloses components in the mixture behave in the same way as they do separately. Also it is seen that the decomposition process shifts to higher temperatures at higher heating rates as a result of the competing effects of heat and mass transfer to the material. (Author)

A new approach to non-isothermal models for nematic liquid crystals

Czech Academy of Sciences Publication Activity Database

Feireisl, Eduard; Frémond, M.; Rocca, E.; Schimperna, G.

2012-01-01

Roč. 205, č. 2 (2012), s. 651-672 ISSN 0003-9527 R&D Projects: GA ČR GA201/09/0917 Institutional research plan: CEZ:AV0Z10190503 Keywords : liquid crystals * non-isothermal model * flows Subject RIV: BA - General Mathematics Impact factor: 2.292, year: 2012 http://www.springerlink.com/content/cl205h73077jr810/

Multiphase Model of Semisolid Slurry Generation and Isothermal Holding During Cooling Slope Rheoprocessing of A356 Al Alloy

Science.gov (United States)

Das, Prosenjit; Samanta, Sudip K.; Mondal, Biswanath; Dutta, Pradip

2018-04-01

In the present paper, we present an experimentally validated 3D multiphase and multiscale solidification model to understand the transport processes involved during slurry generation with a cooling slope. In this process, superheated liquid alloy is poured at the top of the cooling slope and allowed to flow along the slope under the influence of gravity. As the melt flows down the slope, it progressively loses its superheat, starts solidifying at the melt/slope interface with formation of solid crystals, and eventually exits the slope as semisolid slurry. In the present simulation, the three phases considered are the parent melt as the primary phase, and the solid grains and air as secondary phases. The air phase forms a definable air/liquid melt interface as the free surface. After exiting the slope, the slurry fills an isothermal holding bath maintained at the slope exit temperature, which promotes further globularization of microstructure. The outcomes of the present model include prediction of volume fractions of the three different phases considered, grain evolution, grain growth, size, sphericity and distribution of solid grains, temperature field, velocity field, macrosegregation and microsegregation. In addition, the model is found to be capable of making predictions of morphological evolution of primary grains at the onset of isothermal coarsening. The results obtained from the present simulations are validated by performing quantitative image analysis of micrographs of the rapidly oil-quenched semisolid slurry samples, collected from strategic locations along the slope and from the isothermal slurry holding bath.

Ultrasmall volume molecular isothermal amplification in microfluidic chip with advanced surface processing

International Nuclear Information System (INIS)

Huang Guoliang; Yang Xiaoyong; Ma Li; Yang Xu

2011-01-01

In this paper, we developed a metal micro-fluidic chip with advanced surface processing for ultra-small volume molecular isothermal amplification. This method takes advantages of the nucleic acid amplification with good stability and consistency, high sensitivity about 31 genomic DNA copies and bacteria specific gene identification. Based on the advanced surface processing, the bioreaction assays of nucleic acid amplification was dropped about 392nl in volume. A high numerical aperture confocal optical detection system was advanced to sensitively monitor the DNA amplification with low noise and high power collecting fluorescence near to the optical diffraction limit. A speedy nucleic acid isothermal amplification was performed in the ultra-small volume microfluidic chip, where the time at the inflexions of second derivative to DNA exponential amplified curves was brought forward and the sensitivity was improved about 65 folds to that of in current 25μl Ep-tube amplified reaction, which indicates a promising clinic molecular diagnostics in the droplet amplification.

Accuracy of loop-mediated isothermal amplification for diagnosis of human leptospirosis in Thailand.

Science.gov (United States)

Sonthayanon, Piengchan; Chierakul, Wirongrong; Wuthiekanun, Vanaporn; Thaipadungpanit, Janjira; Kalambaheti, Thareerat; Boonsilp, Siriphan; Amornchai, Premjit; Smythe, Lee D; Limmathurotsakul, Direk; Day, Nicholas P; Peacock, Sharon J

2011-04-01

There is a lack of diagnostic tests for leptospirosis in technology-restricted settings. We developed loop-mediated isothermal amplification (LAMP) specific for the 16S ribosomal RNA gene (rrs) of pathogenic and intermediate group Leptospira species. The lower limit of detection was 10 genomic equivalents/reaction, and analytical specificity was high; we observed positive reactions for pathogenic/intermediate groups and negative reactions for non-pathogenic Leptospira species and other bacterial species. We evaluated this assay in Thailand by using a case-control study of 133 patients with laboratory-proven leptospirosis and 133 patients with other febrile illnesses. Using admission blood, we found that the rrs LAMP showed positive results in 58 of 133 cases (diagnostic sensitivity = 43.6, 95% confidence interval [CI] = 35.0-52.5) and in 22 of 133 controls (diagnostic specificity = 83.5, 95% CI = 76.0-89.3). Sensitivity was high for 39 patients who were culture positive for Leptospira spp. (84.6, 95% CI = 69.5-94.1). The rrs LAMP can provide an admission diagnosis in approximately half of patients with leptospirosis, but its clinical utility is reduced by a lower specificity.

A study by non-isothermal thermal methods of spruce wood bark materialss after their application for dye removal

Directory of Open Access Journals (Sweden)

VIORICA DULMAN

2005-11-01

Full Text Available This paper deals with a study of some materials obtained from spruce bark (Picea abies, Romania, after retention of some dyes frequently used in dyeing processes in the textile industry and waste water treatment. These materials obtained by dye retention exhibit a particular thermal behavior which is different from that of the blank sample (spruce bark. The characteristic temperatures, weight losses, the residue remaining after thermo-oxidative degradation, as well as the activation energies of the significant thermo-destruction stages, estimated from non-isothermal thermogravimetric data, together with the thermal quantities calculated from DTAdata support the conclusion presented in a previous study on dye retention from aqueous solution. The obtained results made evident that, under optimal retention conditions, spruce bark shows the highest retention capacity for the Basic Blue dye, followed by Direct Brown 95 and Direct Brown 2.

Determination of effective moisture diffusivity and drying kinetics for poplar sawdust by thermogravimetric analysis under isothermal condition.

Science.gov (United States)

Chen, Dengyu; Zheng, Yan; Zhu, Xifeng

2012-03-01

The current study presents a thermogravimetric method to determine the effective moisture diffusivity and drying kinetics of biomass. Drying experiments on poplar sawdust were performed at four temperatures (60, 70, 80, and 90°C) by a thermogravimetric analyzer (TGA). The major assumption in experimentally determining effective diffusivity by Fick's diffusion equation is that drying is mass transfer limited and temperature remains isothermal during drying. The results indicated that TGA could well achieve these determining conditions. The drying process of sawdust mostly took place in the falling rate period. Midilli-Kucuk model showed the best fit for all experimental data. The effective diffusivity values changed from 9.38 × 10(-10)m(2)/s to 1.38 × 10(-9)m(2)/s within the given temperature range, and the activation energy was calculated to be 12.3 kJ/mol. Copyright © 2011 Elsevier Ltd. All rights reserved.

Computational multiple steady states for enzymatic esterification of ethanol and oleic acid in an isothermal CSTR.

Science.gov (United States)

Ho, Pang-Yen; Chuang, Guo-Syong; Chao, An-Chong; Li, Hsing-Ya

2005-05-01

The capacity of complex biochemical reaction networks (consisting of 11 coupled non-linear ordinary differential equations) to show multiple steady states, was investigated. The system involved esterification of ethanol and oleic acid by lipase in an isothermal continuous stirred tank reactor (CSTR). The Deficiency One Algorithm and the Subnetwork Analysis were applied to determine the steady state multiplicity. A set of rate constants and two corresponding steady states are computed. The phenomena of bistability, hysteresis and bifurcation are discussed. Moreover, the capacity of steady state multiplicity is extended to the family of the studied reaction networks.

Effect of isothermal aging on the microstructure and properties of as-cast Mg-Gd-Y-Zr alloy

Energy Technology Data Exchange (ETDEWEB)

Liang Shuquan [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Guan Dikai, E-mail: gdk199@126.com [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Tan Xiaoping; Chen Liang; Tang Yan [School of Material Science and Engineering, Central South University, Changsha 410083 (China)

2011-01-25

Research highlights: {yields} The improvement of the hardness of the peak-aged alloys at 200 deg. C, 225 deg. C and 250 deg. C is mainly ascribed to the presence of the {beta}' phase. {yields} The alloy peak-aged at 200 deg. C displays the highest hardness owing to the existence of a great many {beta}' precipitates with a quite small size and uniform distribution in the matrix. {yields} The corrosion rates of the peak-aged samples increase as the isothermal aging temperature rise. The {beta}' precipitates are larger and appear to be more active as galvanic cathodes for the alloy peak-aged at the higher aging temperatures. {yields} Therefore, in our paper, optimal mechanical properties and good corrosion resistance in 5% NaCl solutions are obtained simultaneously when the alloy is aged at 200 deg. C for 120 h. - Abstract: The microstructure of Mg-7Gd-3Y-0.4Zr (wt.%) alloy during isothermal aging at 200 deg. C, 225 deg. C and 250 deg. C was investigated using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction. The mechanical properties of the peak-aged materials were evaluated by using Vickers hardness values, and their corrosion resistance was studied by using immersion tests, salt spray tests and electrochemical measurements in 5% NaCl solutions (wt.%). The results show that owing to the existence of a great many {beta}' precipitates with a quite small size and uniform distribution in the matrix, optimal mechanical properties and good corrosion resistance in 5% NaCl solutions are obtained when the alloy is aged at 200 deg. C for 120 h. The potentiodynamic polarization curves show that the corrosion current densities of the cathodic hydrogen evolution on the alloy peak-aged at 200 deg. C is lower than those for specimens of the alloy aged at 225 deg. C and 250 deg. C, which agrees fairly well with the microstructures of the alloys.

Experimental study of water desorption isotherms and thin-layer convective drying kinetics of bay laurel leaves

Science.gov (United States)

Ghnimi, Thouraya; Hassini, Lamine; Bagane, Mohamed

2016-12-01

The aim of this work is to determine the desorption isotherms and the drying kinetics of bay laurel leaves ( Laurus Nobilis L.). The desorption isotherms were performed at three temperature levels: 50, 60 and 70 °C and at water activity ranging from 0.057 to 0.88 using the statistic gravimetric method. Five sorption models were used to fit desorption experimental isotherm data. It was found that Kuhn model offers the best fitting of experimental moisture isotherms in the mentioned investigated ranges of temperature and water activity. The Net isosteric heat of water desorption was evaluated using The Clausius-Clapeyron equation and was then best correlated to equilibrium moisture content by the empirical Tsami's equation. Thin layer convective drying curves of bay laurel leaves were obtained for temperatures of 45, 50, 60 and 70 °C, relative humidity of 5, 15, 30 and 45 % and air velocities of 1, 1.5 and 2 m/s. A non linear regression procedure of Levenberg-Marquardt was used to fit drying curves with five semi empirical mathematical models available in the literature, The R2 and χ2 were used to evaluate the goodness of fit of models to data. Based on the experimental drying curves the drying characteristic curve (DCC) has been established and fitted with a third degree polynomial function. It was found that the Midilli Kucuk model was the best semi-empirical model describing thin layer drying kinetics of bay laurel leaves. The bay laurel leaves effective moisture diffusivity and activation energy were also identified.

Error analysis for 1-1/2-loop semiscale system isothermal test data

International Nuclear Information System (INIS)

Feldman, E.M.; Naff, S.A.

1975-05-01

An error analysis was performed on the measurements made during the isothermal portion of the Semiscale Blowdown and Emergency Core Cooling (ECC) Project. A brief description of the measurement techniques employed, identification of potential sources of errors, and quantification of the errors associated with data is presented. (U.S.)

Convective heat transport of high-pressure flows inside active, thick walled-tubes with isothermal outer surfaces: usage of Nusselt correlation equations for an inactive, thin walled-tube

Energy Technology Data Exchange (ETDEWEB)

Campo, Antonio [Idaho State Univ., Nuclear Engineering Dept., Pocatello, ID (United States); Sanchez, Alejo [Universidad de los Andes, Depto. de Ingenieria Mecanica, Merida (Venezuela)

1998-03-01

A semi-analytical analysis was conducted for the prediction of the mean bulk- and interface temperatures of gaseous and liquid fluids moving laminarly at high pressures inside thick-walled metallic tubes. The outer surfaces of the tubes are isothermal. The central goal of this article is to critically examine the thermal response of this kind of in-tube flows utilizing two versions of the 1-D lumped model: one is differential-numerical while the other is differential-algebraic. For the former, the local Nusselt number characterizing an inactive, isothermal tube was taken from correlation equations reported in the heat transfer literature. For the latter, a streamwise-mean Nusselt number associated with an active, isothermal tube was taken from standard correlation equations that appear in text-books on basic heat transfer. For the two different versions of the 1-D lumped model tested, the computed results consistently demonstrate that the differential-algebraic, provides accurate estimates of both the mean bulk- and the interface temperatures when compared with those temperature results computed with formal 2-D differential models. (author)

Predicting heavy metals' adsorption edges and adsorption isotherms on MnO2 with the parameters determined from Langmuir kinetics.

Science.gov (United States)

Hu, Qinghai; Xiao, Zhongjin; Xiong, Xinmei; Zhou, Gongming; Guan, Xiaohong

2015-01-01

Although surface complexation models have been widely used to describe the adsorption of heavy metals, few studies have verified the feasibility of modeling the adsorption kinetics, edge, and isotherm data with one pH-independent parameter. A close inspection of the derivation process of Langmuir isotherm revealed that the equilibrium constant derived from the Langmuir kinetic model, KS-kinetic, is theoretically equivalent to the adsorption constant in Langmuir isotherm, KS-Langmuir. The modified Langmuir kinetic model (MLK model) and modified Langmuir isotherm model (MLI model) incorporating pH factor were developed. The MLK model was employed to simulate the adsorption kinetics of Cu(II), Co(II), Cd(II), Zn(II) and Ni(II) on MnO2 at pH3.2 or 3.3 to get the values of KS-kinetic. The adsorption edges of heavy metals could be modeled with the modified metal partitioning model (MMP model), and the values of KS-Langmuir were obtained. The values of KS-kinetic and KS-Langmuir are very close to each other, validating that the constants obtained by these two methods are basically the same. The MMP model with KS-kinetic constants could predict the adsorption edges of heavy metals on MnO2 very well at different adsorbent/adsorbate concentrations. Moreover, the adsorption isotherms of heavy metals on MnO2 at various pH levels could be predicted reasonably well by the MLI model with the KS-kinetic constants. Copyright © 2014. Published by Elsevier B.V.

Asymptotic solution of the non-isothermal Cahn-Hilliard system

International Nuclear Information System (INIS)

Omel'yanov, G.A.

1995-05-01

The non-isothermal Cahn-Hillard questions with a small parameter in the n-dimensional case (n = 2.3) are considered. The small parameter is proportional both to the relaxation time and to the linear scale of transition zone, so the large time process is examined. The asymptotic solution describing the free interface dynamics is constructed. As the small parameter tends to zero, the limiting solution satisfies the modified Stefan problem with corrected Gibbs-Thomson law. The justification of the asymptotic solution is proved. (author). 26 refs

TAO/TRITON, RAMA, and PIRATA Buoys, Daily, 1977-present, 20C Isotherm Depth

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has daily 20C Isotherm Depth data (the depth at which the ocean temperature is 20C) from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/...

Experimental Adsorption Isotherm of Methane onto Activated Carbon at Sub- and Supercritical Temperatures

KAUST Repository

Rahman, Kazi Afzalur; Loh, Wai Soong; Yanagi, Hideharu; Chakraborty, Anutosh; Saha, Bidyut Baran; Chun, Won Gee; Ng, Kim Choon

2010-01-01

This paper presents the experimentally measured adsorption isotherm data for methane onto the pitch-based activated carbon type Maxsorb III for temperatures ranging from (120 to 220) K and pressures up to 1.4 MPa. These data are useful to study

Specific detection of Pectobacterium carotovorum by loop-mediated isothermal amplification.

Science.gov (United States)

Yasuhara-Bell, Jarred; Marrero, Glorimar; De Silva, Asoka; Alvarez, Anne M

2016-12-01

Potatoes are an important agroeconomic crop worldwide and maceration diseases caused by pectolytic bacterial pathogens result in significant pre- and post-harvest losses. Pectobacterium carotovorum shares a common host range with other Pectobacterium spp. and other members of the Enterobacteriaceae, such as Dickeya spp. As these pathogens cannot be clearly differentiated on the basis of the symptoms they cause, improved methods of identification are critical for the determination of sources of contamination. Current standardized methods for the differentiation of pectolytic species are time consuming and require trained personnel, as they rely on traditional bacteriological practices that do not always produce conclusive results. In this growing world market, there is a need for rapid diagnostic tests that can differentiate between pectolytic pathogens, as well as separate them from non-pectolytic enteric bacteria associated with soft rots of potato. An assay has been designed previously to detect the temperate pathogen Pectobacterium atrosepticum, but there is currently no recognized rapid assay for the detection of the tropical/subtropical counterpart, Pectobacterium carotovorum. This report describes the development of a loop-mediated isothermal amplification (LAMP) assay that detects P. carotovorum with high specificity. The assay was evaluated using all known species of Pectobacterium and only showed positive reactions for P. carotovorum. This assay was also tested against 15 non-target genera of plant-associated bacteria and did not produce any false positives. The LAMP assay described here can be used as a rapid test for the differentiation of P. carotovorum from other pectolytic pathogens, and its gene target can be the basis for the development of other molecular-based detection assays. © 2016 BSPP and John Wiley & Sons Ltd.

Freundlich and Langmuir adsorption isotherms and kinetics for the removal of Tartrazine from aqueous solutions using hen feathers

Energy Technology Data Exchange (ETDEWEB)

Mittal, Alok [Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal, 462 007 MP (India)]. E-mail: aljymittal@yahoo.co.in; Kurup, Lisha [Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal, 462 007 MP (India); Mittal, Jyoti [Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal, 462 007 MP (India)

2007-07-19

Tartrazine, a yellow menace, is widely being used in cosmetics, foodstuffs, medicines and textile. It is carcinogenic and also catalyzes allergic problems. In the present work the ability to remove Tartrazine from aqueous solutions has been studied using waste material-hen feathers, as adsorbent. Effects of pH, concentration of the dye, temperature and adsorbent dosage have been studied. Equilibrium isotherms for the adsorption of the dye were measured experimentally. Results were analyzed by the Freundlich and Langmuir equation at different temperatures and determined the characteristic parameters for each adsorption isotherm. The adsorption process has been found endothermic in nature and thermodynamic parameters, Gibb's free energy ({delta}G{sup o}), change in enthalpy ({delta}H{sup o}) and change in entropy ({delta}S{sup o}) have been calculated. The paper also includes results on the kinetic measurements of adsorption of the dye on hen feathers at different temperatures. By rate expression and treatment of data it has been established that the adsorption of Tartrazine over hen feathers follows a first-order kinetics and a film diffusion mechanism operates at all the temperatures.

Biosorption of Cd(II) and Zn(II) by nostoc commune: isotherm and kinetics studies

Energy Technology Data Exchange (ETDEWEB)

Morsy, Fatthy M. [Faculty of Science, Botany Department, Assiut University, Assiut (Egypt); Hassan, Sedky H.A. [Department of Biological Environment, Kangwon National University, Kangwon-do (Korea, Republic of); Koutb, Mostafa [Faculty of Science, Botany Department, Assiut University, Assiut (Egypt); Umm Al-Qura University, Faculty of Applied Science, Biology Department, Mecca (Saudi Arabia)

2011-07-15

In this study, Nostoc commune (cyanobacterium) was used as an inexpensive and efficient biosorbent for Cd(II) and Zn(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Zn(II) biosorption such as pH 2.0-7.0, initial metal concentration 0.0-300 mg/L and contact time 0-120 min were studied. Optimum pH for removal of Cd(II) and Zn(II) was 6.0, while the contact time was 30 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by infrared (IR) technique. IR analysis of bacterial biomass revealed the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for biosorption of Cd(II) and Zn (II). The maximum biosorption capacities for Cd(II) and Zn(II) biosorption by N. commune calculated from Langmuir biosorption isotherm were 126.32 and 115.41 mg/g, respectively. The biosorption isotherm for two biosorbents fitted well with Freundlich isotherm than Langmuir model with correlation coefficient (r{sup 2} < 0.99). The biosorption kinetic data were fitted well with the pseudo-second-order kinetic model. Thus, this study indicated that the N. commune is an efficient biosorbent for the removal of Cd(II) and Zn(II) from aqueous solutions. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Thermo-kinetic prediction of metastable and stable phase precipitation in Al–Zn–Mg series aluminium alloys during non-isothermal DSC analysis

International Nuclear Information System (INIS)

Lang, Peter; Wojcik, Tomasz; Povoden-Karadeniz, Erwin; Falahati, Ahmad; Kozeschnik, Ernst

2014-01-01

Highlights: • Comparison of laboratory Al–Zn–Mg alloy to industrial Al 7xxx series. • Heat flow evolution during non-isothermal DSC analysis is calculated. • TEM investigations of laboratory Al–Zn–Mg alloy at three pronounced temperatures. • Simulation and modelling of precipitation sequence. • Calculation and prediction of heat flow curves of Al 7xxx series. - Abstract: The technological properties of heat treatable Al–Zn–Mg alloys originate in the morphology and distribution of metastable particles. Starting from the solution-annealed condition, this paper describes the precipitate evolution during non-isothermal temperature changes, namely continuous heating differential scanning calorimetry (DSC) analysis. The distribution and the morphology of the metastable and stable precipitates and the heat flow accompanying the precipitation process is investigated experimentally and calculated by numerical thermo-kinetic simulations. The computer simulation results of the sizes and distributions are confirmed by transmission electron microscopy (TEM). The theoretical background and the results of the investigations are discussed

Thermo-kinetic prediction of metastable and stable phase precipitation in Al–Zn–Mg series aluminium alloys during non-isothermal DSC analysis

Energy Technology Data Exchange (ETDEWEB)

Lang, Peter, E-mail: pl404@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS (United Kingdom); Wojcik, Tomasz [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Povoden-Karadeniz, Erwin [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Christian Doppler Laboratory “Early Stages of Precipitation”, Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Falahati, Ahmad [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Kozeschnik, Ernst [Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria); Christian Doppler Laboratory “Early Stages of Precipitation”, Institute of Materials Science and Technology, Vienna University of Technology, Favoritenstraße 9-11, Vienna 1040 (Austria)

2014-10-01

Highlights: • Comparison of laboratory Al–Zn–Mg alloy to industrial Al 7xxx series. • Heat flow evolution during non-isothermal DSC analysis is calculated. • TEM investigations of laboratory Al–Zn–Mg alloy at three pronounced temperatures. • Simulation and modelling of precipitation sequence. • Calculation and prediction of heat flow curves of Al 7xxx series. - Abstract: The technological properties of heat treatable Al–Zn–Mg alloys originate in the morphology and distribution of metastable particles. Starting from the solution-annealed condition, this paper describes the precipitate evolution during non-isothermal temperature changes, namely continuous heating differential scanning calorimetry (DSC) analysis. The distribution and the morphology of the metastable and stable precipitates and the heat flow accompanying the precipitation process is investigated experimentally and calculated by numerical thermo-kinetic simulations. The computer simulation results of the sizes and distributions are confirmed by transmission electron microscopy (TEM). The theoretical background and the results of the investigations are discussed.

Determination of storage conditions for new biscuits using their sorption isotherms

OpenAIRE

G. Diukareva; A. Pak; A. Gasanova

2015-01-01

Introduction For the formation of biscuits quality natural carrier of iodine and sweetener from stevia leaves were used. Desorption of moisture is the dominant process, which will determine the guaranteed shelf life of biscuits. The conditions for the developed biscuits storage was determined by investigating of sorption isotherms and kinetics of reaching the equilibrium moisture content. Materials and Methods. The objects of stud...

Isothermal amplification of environmental DNA (eDNA for direct field-based monitoring and laboratory confirmation of Dreissena sp.

Directory of Open Access Journals (Sweden)

Maggie R Williams

Full Text Available Loop-mediated isothermal amplification (LAMP of aquatic invasive species environmental DNA (AIS eDNA was used for rapid, sensitive, and specific detection of Dreissena sp. relevant to the Great Lakes (USA basin. The method was validated for two uses including i direct amplification of eDNA using a hand filtration system and ii confirmation of the results after DNA extraction using a conventional thermal cycler run at isothermal temperatures. Direct amplification eliminated the need for DNA extraction and purification and allowed detection of target invasive species in grab or concentrated surface water samples, containing both free DNA as well as larger cells and particulates, such as veligers, eggs, or seeds. The direct amplification method validation was conducted using Dreissena polymorpha and Dreissena bugensis and uses up to 1 L grab water samples for high target abundance (e.g., greater than 10 veligers (larval mussels per L for Dreissena sp. or 20 L samples concentrated through 35 μm nylon screens for low target abundance, at less than 10 veligers per liter water. Surface water concentrate samples were collected over a period of three years, mostly from inland lakes in Michigan with the help of a network of volunteers. Field samples collected from 318 surface water locations included i filtered concentrate for direct amplification validation and ii 1 L grab water sample for eDNA extraction and confirmation. Though the extraction-based protocol was more sensitive (resulting in more positive detections than direct amplification, direct amplification could be used for rapid screening, allowing for quicker action times. For samples collected between May and August, results of eDNA direct amplification were consistent with known presence/absence of selected invasive species. A cross-platform smartphone application was also developed to disseminate the analyzed results to volunteers. Field tests of the direct amplification protocol using a

Numerical study of free convection in an enclosure with two vertical isothermal walls

International Nuclear Information System (INIS)

Barletta, A.; Rossi di Schio, E.; Zanchini, E.; Nobile, E.; Pinto, F.

2005-01-01

In this paper, natural convection is studied in a 2D-cavity with two vertical isothermal walls, kept at different temperatures, and two adiabatic walls which are either straight (rectangular cavity) or elliptic (modified rectangular cavity). The local mass, momentum and energy balance equations are written in a dimensionless form and solved numerically, by means of two different software packages based on Galerkin finite element methods. With reference to a Prandtl number of 0.71, two rectangular cavities are studied: a square one and a cavity with height double than width. Then, for each value of the ratio between height and width, two cavities with elliptic boundaries are investigated. The numerical solution shows that the elliptic boundaries enhance the mean Nusselt number and the dimensionless mean kinetic energy of the fluid. (authors)

Liouvillian integrability of gravitating static isothermal fluid spheres

International Nuclear Information System (INIS)

Iacono, Roberto; Llibre, Jaume

2014-01-01

We examine the integrability properties of the Einstein field equations for static, spherically symmetric fluid spheres, complemented with an isothermal equation of state, ρ = np. In this case, Einstein's equations can be reduced to a nonlinear, autonomous second order ordinary differential equation (ODE) for m/R (m is the mass inside the radius R) that has been solved analytically only for n = −1 and n = −3, yielding the cosmological solutions by De Sitter and Einstein, respectively, and for n = −5, case for which the solution can be derived from the De Sitter's one using a symmetry of Einstein's equations. The solutions for these three cases are of Liouvillian type, since they can be expressed in terms of elementary functions. Here, we address the question of whether Liouvillian solutions can be obtained for other values of n. To do so, we transform the second order equation into an equivalent autonomous Lotka–Volterra quadratic polynomial differential system in R 2 , and characterize the Liouvillian integrability of this system using Darboux theory. We find that the Lotka–Volterra system possesses Liouvillian first integrals for n = −1, −3, −5, which descend from the existence of invariant algebraic curves of degree one, and for n = −6, a new solvable case, associated to an invariant algebraic curve of higher degree (second). For any other value of n, eventual first integrals of the Lotka–Volterra system, and consequently of the second order ODE for the mass function must be non-Liouvillian. This makes the existence of other solutions of the isothermal fluid sphere problem with a Liouvillian metric quite unlikely

Liouvillian integrability of gravitating static isothermal fluid spheres

Energy Technology Data Exchange (ETDEWEB)

Iacono, Roberto, E-mail: roberto.iacono@enea.it [ENEA-C. R. Casaccia, Via Anguillarese 301, 00123 Roma (Italy); Llibre, Jaume, E-mail: jllibre@mat.uab.cat [Departament de Matemàtiques, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain)

2014-10-01

We examine the integrability properties of the Einstein field equations for static, spherically symmetric fluid spheres, complemented with an isothermal equation of state, ρ = np. In this case, Einstein's equations can be reduced to a nonlinear, autonomous second order ordinary differential equation (ODE) for m/R (m is the mass inside the radius R) that has been solved analytically only for n = -1 and n = -3, yielding the cosmological solutions by De Sitter and Einstein, respectively, and for n = -5, case for which the solution can be derived from the De Sitter's one using a symmetry of Einstein's equations. The solutions for these three cases are of Liouvillian type, since they can be expressed in terms of elementary functions. Here, we address the question of whether Liouvillian solutions can be obtained for other values of n. To do so, we transform the second order equation into an equivalent autonomous Lotka–Volterra quadratic polynomial differential system in R² and characterize the Liouvillian integrability of this system using Darboux theory. We find that the Lotka–Volterra system possesses Liouvillian first integrals for n = -1, -3, -5, which descend from the existence of invariant algebraic curves of degree one, and for n = -6, a new solvable case, associated to an invariant algebraic curve of higher degree (second). For any other value of n, eventual first integrals of the Lotka–Volterra system, and consequently of the second order ODE for the mass function must be non-Liouvillian. This makes the existence of other solutions of the isothermal fluid sphere problem with a Liouvillian metric quite unlikely.

Non-isothermal precipitation behaviors of Al-Mg-Si-Cu alloys with different Zn contents

International Nuclear Information System (INIS)

Guo, M.X.; Zhang, Y.; Zhang, X.K.; Zhang, J.S.; Zhuang, L.Z.

2016-01-01

The non-isothermal precipitation behaviors of Al–Mg–Si–Cu alloys with different Zn contents were investigated by differential scanning calorimetry (DSC) analysis, hardness measurement and high resolution transmission electron microscope characterization. The results show that Zn addition has a significant effect on the GP zone dissolution and precipitation of Al-Mg-Si-Cu alloys. And their activation energies change with the changes of Zn content and aging conditions. Precipitation kinetics can be improved by adding 0.5 wt% or 3.0 wt%Zn, while be suppressed after adding 1.5 wt%Zn. The Mg-Si precipitates (GP zones and β″) are still the main precipitates in the Al-Mg-Si-Cu alloys after heated up to 250 °C, and no Mg-Zn precipitates are observed in the Zn-added alloy due to the occurrence of Mg-Zn precipitates reversion. The measured age-hardening responses of the alloys are corresponding to the predicted results by the established precipitation kinetic equations. Additionally, a double-hump phenomenon of hardness appears in the artificial aging of pre-aged alloy with 3.0 wt% Zn addition, which resulted from the formation of pre-β″ and β″ precipitates. Finally, the precipitation mechanism of Al-Mg-Si-Cu alloys with different Zn contents was proposed based on the microstructure evolution and interaction forces between Mg, Si and Zn atoms.

A sample holder for the study of isothermal heat of hydration of cement

DEFF Research Database (Denmark)

Hansen, Per Freiesleben; Jensen, Ole Mejlhede

1998-01-01

Different techniques for measuring heat of hydration of cement are discussed, and a sample holder designed specially for measuring isothermal heat of hydration is described. A particular characteristic of the sample holder is the vacuum mixing technique which ensures a momentary and homogeneous...

Isothermal microcalorimetry for antifungal susceptibility testing of Mucorales, Fusarium spp., and Scedosporium spp.

NARCIS (Netherlands)

Furustrand Tafin, U.; Meis, J.F.G.M.; Trampuz, A.

2012-01-01

We evaluated isothermal microcalorimetry for real-time susceptibility testing of non-Aspergillus molds. MIC and minimal effective concentration (MEC) values of Mucorales (n = 4), Fusarium spp. (n = 4), and Scedosporium spp. (n = 4) were determined by microbroth dilution according to the Clinical

Modeling of isothermal bubbly flow with interfacial area transport equation and bubble number density approach

Energy Technology Data Exchange (ETDEWEB)

Sari, Salih [Hacettepe University, Department of Nuclear Engineering, Beytepe, 06800 Ankara (Turkey); Erguen, Sule [Hacettepe University, Department of Nuclear Engineering, Beytepe, 06800 Ankara (Turkey); Barik, Muhammet; Kocar, Cemil; Soekmen, Cemal Niyazi [Hacettepe University, Department of Nuclear Engineering, Beytepe, 06800 Ankara (Turkey)

2009-03-15

In this study, isothermal turbulent bubbly flow is mechanistically modeled. For the modeling, Fluent version 6.3.26 is used as the computational fluid dynamics solver. First, the mechanistic models that simulate the interphase momentum transfer between the gas (bubbles) and liquid (continuous) phases are investigated, and proper models for the known flow conditions are selected. Second, an interfacial area transport equation (IATE) solution is added to Fluent's solution scheme in order to model the interphase momentum transfer mechanisms. In addition to solving IATE, bubble number density (BND) approach is also added to Fluent and this approach is also used in the simulations. Different source/sink models derived for the IATE and BND models are also investigated. The simulations of experiments based on the available data in literature are performed by using IATE and BND models in two and three-dimensions. The results show that the simulations performed by using IATE and BND models agree with each other and with the experimental data. The simulations performed in three-dimensions give better agreement with the experimental data.

Modeling of isothermal bubbly flow with interfacial area transport equation and bubble number density approach

International Nuclear Information System (INIS)

Sari, Salih; Erguen, Sule; Barik, Muhammet; Kocar, Cemil; Soekmen, Cemal Niyazi

2009-01-01

In this study, isothermal turbulent bubbly flow is mechanistically modeled. For the modeling, Fluent version 6.3.26 is used as the computational fluid dynamics solver. First, the mechanistic models that simulate the interphase momentum transfer between the gas (bubbles) and liquid (continuous) phases are investigated, and proper models for the known flow conditions are selected. Second, an interfacial area transport equation (IATE) solution is added to Fluent's solution scheme in order to model the interphase momentum transfer mechanisms. In addition to solving IATE, bubble number density (BND) approach is also added to Fluent and this approach is also used in the simulations. Different source/sink models derived for the IATE and BND models are also investigated. The simulations of experiments based on the available data in literature are performed by using IATE and BND models in two and three-dimensions. The results show that the simulations performed by using IATE and BND models agree with each other and with the experimental data. The simulations performed in three-dimensions give better agreement with the experimental data

A self-consistent model of an isothermal tokamak

Science.gov (United States)

McNamara, Steven; Lilley, Matthew

2014-10-01

Continued progress in liquid lithium coating technologies have made the development of a beam driven tokamak with minimal edge recycling a feasibly possibility. Such devices are characterised by improved confinement due to their inherent stability and the suppression of thermal conduction. Particle and energy confinement become intrinsically linked and the plasma thermal energy content is governed by the injected beam. A self-consistent model of a purely beam fuelled isothermal tokamak is presented, including calculations of the density profile, bulk species temperature ratios and the fusion output. Stability considerations constrain the operating parameters and regions of stable operation are identified and their suitability to potential reactor applications discussed.

Dispersive kinetic model for the non-isothermal reduction of nickel oxide by hydrogen

International Nuclear Information System (INIS)

Adnadevic, Borivoj; Jankovic, Bojan

2008-01-01

The kinetics of the non-isothermal reduction process of powder nickel oxide samples using hydrogen was investigated by temperature-programmed experiments at the different constant heating rates. The new procedure for the determination of density distribution function of activation energies (ddfE a ), evaluated from the experimentally obtained non-isothermal conversion curves, was developed. The analytical relationships between the corresponding thermo-kinetic parameters for the investigated reduction process were established. From the influence of heating rate on the basic characteristics of ddfE a 's, it was concluded that the evaluated ddfE a 's are completely independent of the heating rate (v h ). It was found that the value of activation energy at the peak of the distribution curve (E a,max ), at all considered heating rates, is in good agreement with the value of E a,0 (96.6 kJ mol -1 ) calculated from the isoconversional dependence of activation energy, in the conversion range of 0.20≤α≤0.60. From the appearances of the true compensation effect, it was concluded that the factor that produces the changes of kinetic parameter values is a conversion fraction (α). Using the model prediction, the experimentally obtained conversion curves are completely described by the evaluated distribution curves (g(E a ) vhj ) at all considered heating rates. It was concluded that the assumption about the distribution of potential energies of oxygen vacancies presented in NiO samples leads to the distribution of activation energies, which determine the kinetics of non-isothermal reduction processes

Using Adsorption Isotherm Studies to Determine Crosslinked Polymeric Adsorbent Performance in Heavy Metals Removal from Water

Directory of Open Access Journals (Sweden)

Nasrin Sheikh

2015-01-01

Full Text Available Polymeric adsorbents are useful tools for removing heavy metals from aqueous solutions. Adsorption models are efficient tools for accurate prediction and evaluation of the practical adsorption process in real situation. In this study, the two isotherms of Langmuir and Dubinin-Radushkevich models were employed to investigate the absorption performance of chitosan, PVA, and chitosan/PVA blend (with a weight ratio of 1:1 in the removal of Mn (II and Ni (II from aqueous solutions. The PVA adsorbent was crosslinked by both chemical and radiation methods while the others were crosslinked only chemically due to Chitosan’s lack of resistance to radiation. The results showed that the Langmuir model fitted the experimental data better than the Dubinin-Radushkevich one for both metals. The maximum adsorption capacity (qmax of the Langmuir model showed that the PVA/Chitosan adsorbent had the best adsorption compared to other adsorbents, with 52.63 mg/g for Ni and 30.30 mg/g for Mn (evidently more Ni was absorbed than Mn. Also, maximum adsorption by the chemically crosslinked PVA was 38.46 mg/g for Ni and 19.23 mg/g for Mn, which exhibits a higher level than adsorption by the radiation crosslinked PVA The results indicate that absorption capacity depends on the type of adsorbed metal, absorbent structure, and the crosslinking method employed.

GMO detection in food and feed through screening by visual loop-mediated isothermal amplification assays.

Science.gov (United States)

Wang, Cong; Li, Rong; Quan, Sheng; Shen, Ping; Zhang, Dabing; Shi, Jianxin; Yang, Litao

2015-06-01

Isothermal DNA/RNA amplification techniques are the primary methodology for developing on-spot rapid nucleic acid amplification assays, and the loop-mediated isothermal amplification (LAMP) technique has been developed and applied in the detection of foodborne pathogens, plant/animal viruses, and genetically modified (GM) food/feed contents. In this study, one set of LAMP assays targeting on eight frequently used universal elements, marker genes, and exogenous target genes, such as CaMV35S promoter, FMV35S promoter, NOS, bar, cry1Ac, CP4 epsps, pat, and NptII, were developed for visual screening of GM contents in plant-derived food samples with high efficiency and accuracy. For these eight LAMP assays, their specificity was evaluated by testing commercial GM plant events and their limits of detection were also determined, which are 10 haploid genome equivalents (HGE) for FMV35S promoter, cry1Ac, and pat assays, as well as five HGE for CaMV35S promoter, bar, NOS terminator, CP4 epsps, and NptII assays. The screening applicability of these LAMP assays was further validated successfully using practical canola, soybean, and maize samples. The results suggested that the established visual LAMP assays are applicable and cost-effective for GM screening in plant-derived food samples.

Kinetics of isothermal annealing of hypochlorite in γ-irradiated potassium chlorate

International Nuclear Information System (INIS)

Arnikar, H.J.; Patil, S.F.; Patil, B.T.

1977-01-01

The kinetics of isothermal annealing of hypochlorite formed in the gamma radiolysis of potassium chlorate crystals have been studied at different temperatures in the range of 100-160 deg C. The hypochlorite is found to anneal by a combination of first and second order processes, the former being fast, virtually reaching completion within a few hours. It is then followed by a slow second order process. (authors)

Isotherm and kinetic studies on adsorption of oil sands process-affected water organic compounds using granular activated carbon.

Science.gov (United States)

Islam, Md Shahinoor; McPhedran, Kerry N; Messele, Selamawit A; Liu, Yang; Gamal El-Din, Mohamed

2018-07-01

The production of oil from oil sands in northern Alberta has led to the generation of large volumes of oil sands process-affected water (OSPW) that was reported to be toxic to aquatic and other living organisms. The toxicity of OSPW has been attributed to the complex nature of OSPW matrix including the inorganic and organic compounds primarily naphthenic acids (NAs: C n H 2n+Z O x ). In the present study, granular activated carbon (GAC) adsorption was investigated for its potential use to treat raw and ozonated OSPW. The results indicated that NA species removal increased with carbon number (n) for a fixed Z number; however, the NA species removal decreased with Z number for a fixed carbon number. The maximum adsorption capacities obtained from Langmuir adsorption isotherm based on acid-extractable fraction (AEF) and NAs were 98.5 mg and 60.9 mg AEF/g GAC and 60 mg and 37 mg NA/g GAC for raw and ozonated OSPW, respectively. It was found that the Freundlich isotherm model best fits the AEF and NA equilibrium data (r 2  ≥ 0.88). The adsorption kinetics showed that the pseudo-second order and intraparticle diffusion models were both appropriate in modeling the adsorption kinetics of AEF and NAs to GAC (r 2  ≥ 0.97). Although pore diffusion was the rate limiting step, film diffusion was still significant for assessing the rate of diffusion of NAs. This study could be helpful to model, design and optimize the adsorption treatment technologies of OSPW and to assess the performance of other adsorbents. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fifth-order amplitude equation for traveling waves in isothermal double diffusive convection

International Nuclear Information System (INIS)

Mendoza, S.; Becerril, R.

2009-01-01

Third-order amplitude equations for isothermal double diffusive convection are known to hold the tricritical condition all along the oscillatory branch, predicting that stable traveling waves exist Only at the onset of the instability. In order to properly describe stable traveling waves, we perform a fifth-order calculation and present explicitly the corresponding amplitude equation.

Determination of storage conditions for new biscuits using their sorption isotherms

Directory of Open Access Journals (Sweden)

G. Diukareva

2015-05-01

Full Text Available Introduction For the formation of biscuits quality natural carrier of iodine and sweetener from stevia leaves were used. Desorption of moisture is the dominant process, which will determine the guaranteed shelf life of biscuits. The conditions for the developed biscuits storage was determined by investigating of sorption isotherms and kinetics of reaching the equilibrium moisture content. Materials and Methods. The objects of study arenewly developed biscuits: "Health" (rich in iodine and with the replacement of 50 % sugar by stevioside, "Light" (with the replacement of 75% of sugar by stevioside and enriched with wheat bran, "Fortified" (containselamine, which is a natural source of iodine. Control – the biscuit prepared according to traditional recipes. Tenzometric method was used to study the sorption equilibrium moisture content. Differential function of pore radius distribution was determined using sorption isotherms and then have been subjected to approximation. Results. New biscuits samples are in the area of polymolecular and monomolecular sorption in the range of the relative air humidity (RAH from 10 to 75 ... 80%. The control sample has less distinct plot of monomolecular sorption (10 to 20% and short- moisture range wich is corresponding with polymolecularsorption (from 20 to 65 ... 70%. There is a moisture absorbtion ofmicrocapillary and swelling of samples when RAHincreases to 75 ... 80% for all the samples. The ratio of average pore radius tothe most likely of the test samples are differentthat wasshown by the investigation of differential function of pore distribution. So this ratio for biscuit "Health" is 5.73, for biscuit "Light" − 2.98,forbiscuit "Fortified"− 4.91 and for the control − 3.88. Conclusions. There’s the sense to store developed biscuits in a cardboard packaging with polymeric covering, if RAH is not more than 75%, and vapor-proof if RAH is above that.

Adsorption of Cd (II) on Modified Granular Activated Carbons: Isotherm and Column Study.

Science.gov (United States)

Rodríguez-Estupiñán, Paola; Erto, Alessandro; Giraldo, Liliana; Moreno-Piraján, Juan Carlos

2017-12-20

In this work, equilibrium and dynamic adsorption tests of cadmium Cd (II) on activated carbons derived from different oxidation treatments (with either HNO₃, H₂O₂, or NaOCl, corresponding to GACoxN, GACoxP, and GACoxCl samples) are presented. The oxidation treatments determined an increase in the surface functional groups (mainly the acidic ones) and a decrease in the pH PZC (except for the GACoxCl sample). A slight alteration of the textural parameters was also observed, which was more significant for the GACoxCl sample, in terms of a decrease of both Brunauer-Emmett-Teller ( BET ) surface area and micropore volume. Adsorption isotherms were determined for all the adsorbents and a significant increase in the adsorption performances of the oxidized samples with respect to the parent material was observed. The performances ranking was GACoxCl > GACoxP > GACoxN > GAC, likely due to the chemical surface properties of the adsorbents. Dynamic tests in a fixed bed column were carried out in terms of breakthrough curves at constant Cd inlet concentration and flow rate. GACoxCl and GACoxN showed a significantly higher value of the breakpoint time, likely due to the higher adsorption capacity. Finally, the dynamic tests were analyzed in light of a kinetic model. In the adopted experimental conditions, the results showed that mass transfer is controlled by internal pore diffusion, in which surface diffusion plays a major role.

Adsorption of Cd (II on Modified Granular Activated Carbons: Isotherm and Column Study

Directory of Open Access Journals (Sweden)

Paola Rodríguez-Estupiñán

2017-12-01

Full Text Available In this work, equilibrium and dynamic adsorption tests of cadmium Cd (II on activated carbons derived from different oxidation treatments (with either HNO3, H2O2, or NaOCl, corresponding to GACoxN, GACoxP, and GACoxCl samples are presented. The oxidation treatments determined an increase in the surface functional groups (mainly the acidic ones and a decrease in the pHPZC (except for the GACoxCl sample. A slight alteration of the textural parameters was also observed, which was more significant for the GACoxCl sample, in terms of a decrease of both Brunauer-Emmett-Teller (BET surface area and micropore volume. Adsorption isotherms were determined for all the adsorbents and a significant increase in the adsorption performances of the oxidized samples with respect to the parent material was observed. The performances ranking was GACoxCl > GACoxP > GACoxN > GAC, likely due to the chemical surface properties of the adsorbents. Dynamic tests in a fixed bed column were carried out in terms of breakthrough curves at constant Cd inlet concentration and flow rate. GACoxCl and GACoxN showed a significantly higher value of the breakpoint time, likely due to the higher adsorption capacity. Finally, the dynamic tests were analyzed in light of a kinetic model. In the adopted experimental conditions, the results showed that mass transfer is controlled by internal pore diffusion, in which surface diffusion plays a major role.

A three-dimensional numerical investigation of trapezoid baffles effect on non-isothermal reactant transport and cell net power in a PEMFC

International Nuclear Information System (INIS)

Perng, Shiang-Wuu; Wu, Horng-Wen

2015-01-01

Highlights: • We study how angle and height of trapezoid baffle affect PEMFC net power. • The jet-type, trapping, and blockage effects augment non-isothermal transport in flow channel. • Greater angles and heights of trapezoid baffles provide more reactant to the catalyst layer. • Baffles of 1.5 mm and 90° fully block flow channel to show bad heat transfer and large pressure drop. • Maximum enhancement of cell net power is 90% with baffles of 60° angle and 1.125 mm height. - Abstract: The present study performed a three-dimensional numerical simulation to observe how trapezoid baffles affect non-isothermal reactant transports and cell net power in the proton exchange membrane fuel cell (PEMFC) by the SIMPLE-C method. The geometric parameters of trapezoid baffles installed in the gas channel employed in this study include the angle and height with the same gas diffusion and catalyst layers to realize the cell net power considering the effect of liquid water formation on the fluid flow field. The cell net power is adopted to evaluate the real enhancement of cell performance due to the additional pumping power induced by the pressure loss through the PEMFC. The results illustrated that compared with traditional gas channel without baffles, the novel gas channel with trapezoid baffles, whose angle is 60° and height is 1.125 mm, enhances the cell net power best by approximately 90% among all trapezoid baffle designs

Adsorption of Pb(II) from fish sauce using carboxylated cellulose nanocrystal: Isotherm, kinetics, and thermodynamic studies.

Science.gov (United States)

Wang, Nan; Jin, Ru-Na; Omer, A M; Ouyang, Xiao-Kun

2017-09-01

In the present study, a new adsorbent based on carboxylated cellulose nanocrystal (CCN) was developed for the adsorption of Pb(II) from fish sauce. The prepared adsorbent material was characterized by zeta potential, FT-IR, XRD, and XPS tools. The changes in the morphological structure of the developed CCN surface were evidenced by SEM and TEM. The favorable adsorption conditions were selected by studying the contact time, initial concentration, temperature, and concentration of the used glutamic acid and NaCl. The results indicated that the Langmuir isotherm model agrees very well with experimental adsorption data (R 2 =0.9962) with a maximum adsorption capacity 232.56mg/g of Pb(II) at 293.2K. Additionally, data of the adsorption kinetics follow the pseudo-second-order kinetics (R 2 >0.9990). On the other hand, the thermodynamics studies show that the adsorption process is spontaneous and endothermic. Furthermore, the developed CCN could be regenerated using acid treatment with a good reusability for Pb(II) adsorption. The results clearly indicated that the synthesized CCN could be effectively applied as a new material for Pb(II) adsorption from fish sauce solutions. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of the isotherms of ion exchange with using the Mathcad program package

International Nuclear Information System (INIS)

Ochkov, V.F.; Pil'shchikov, A.P.; Solodov, A.P.; Chudova, Yu.V.

2003-01-01

The use of the Mathcad software physical and mathematical package for calculations in thermal power engineering is considered. Propagation of concentration waves in ionite filters was analyzed by the method of characteristics. Formation of the break front of concentrations appearing at different adsorption isotherms is shown [ru

A simple method of evaluating non-isothermal crystallization kinetics in multicomponent polymer systems

Czech Academy of Sciences Publication Activity Database

Kratochvíl, Jaroslav; Kelnar, Ivan

2015-01-01

Roč. 47, October (2015), s. 79-86 ISSN 0142-9418 R&D Projects: GA ČR(CZ) GA13-15255S Institutional support: RVO:61389013 Keywords : non-isothermal crystallization kinetics * cumulative curves * inflection point Subject RIV: JI - Composite Materials Impact factor: 2.350, year: 2015

Simulation on Natural Convection of a Nanofluid along an Isothermal Inclined Plate

Science.gov (United States)

Mitra, Asish

2017-08-01

A numerical algorithm is presented for studying laminar natural convection flow of a nanofluid along an isothermal inclined plate. By means of similarity transformation, the original nonlinear partial differential equations of flow are transformed to a set of nonlinear ordinary differential equations. Subsequently they are reduced to a first order system and integrated using Newton Raphson and adaptive Runge-Kutta methods. The computer codes are developed for this numerical analysis in Matlab environment. Dimensionless velocity, temperature profiles and nanoparticle concentration for various angles of inclination are illustrated graphically. The effects of Prandtl number, Brownian motion parameter and thermophoresis parameter on Nusselt number are also discussed. The results of the present simulation are then compared with previous one available in literature with good agreement.

Desorption isotherms and isosteric heat of 'cajuzinho-do-cerrado' achenes

Directory of Open Access Journals (Sweden)

Karine F. Barbosa

2016-05-01

Full Text Available ABSTRACT The objective of this study was to determine the desorption isotherms of 'cajuzinho-do-cerrado' achenes (Anacardium humile St. Hil. in various conditions of temperature and water activity, as well as to select the one that best represents the phenomenon and to determine the isosteric heat of desorption. The fruits were collected at the Emas National Park, in the municipality of Mineiros-GO, Brazil, pulped and then subjected to drying in silica gel at temperature of 25 ± 2 °C until the moisture contents of 17.6, 13.6, 11.1, 8.7 and 5.3 (d.b.%. After drying, the desorption isotherms were determined by the indirect static method. The water activity (Aw was determined at different temperatures, and the achenes were placed in a B.O.D. chamber, regulated at 10, 20, 30 and 40 °C. Data of hygroscopic equilibrium moisture content were fitted to different mathematical models through non-linear regression analysis, using the Gauss-Newton method. The Copace model was the one that best represented the hygroscopicity of 'cajuzinho-do-cerrado' achenes, while the integral isosteric heat of desorption of 'cajuzinho-do-cerrado' achenes for the moisture content range of 4.51 to 13.40 (% d.b. varied from 2,734.82 to 2,548.49 kJ kg-1.

Reliable prediction of adsorption isotherms via genetic algorithm molecular simulation.

Science.gov (United States)

LoftiKatooli, L; Shahsavand, A

2017-01-01

Conventional molecular simulation techniques such as grand canonical Monte Carlo (GCMC) strictly rely on purely random search inside the simulation box for predicting the adsorption isotherms. This blind search is usually extremely time demanding for providing a faithful approximation of the real isotherm and in some cases may lead to non-optimal solutions. A novel approach is presented in this article which does not use any of the classical steps of the standard GCMC method, such as displacement, insertation, and removal. The new approach is based on the well-known genetic algorithm to find the optimal configuration for adsorption of any adsorbate on a structured adsorbent under prevailing pressure and temperature. The proposed approach considers the molecular simulation problem as a global optimization challenge. A detailed flow chart of our so-called genetic algorithm molecular simulation (GAMS) method is presented, which is entirely different from traditions molecular simulation approaches. Three real case studies (for adsorption of CO 2 and H 2 over various zeolites) are borrowed from literature to clearly illustrate the superior performances of the proposed method over the standard GCMC technique. For the present method, the average absolute values of percentage errors are around 11% (RHO-H 2 ), 5% (CHA-CO 2 ), and 16% (BEA-CO 2 ), while they were about 70%, 15%, and 40% for the standard GCMC technique, respectively.

A NON-ISOTHERMAL THEORY FOR INTERPRETING SODIUM LINES IN TRANSMISSION SPECTRA OF EXOPLANETS

Energy Technology Data Exchange (ETDEWEB)

Heng, Kevin; Lavie, Baptiste [University of Bern, Physics Institute, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Wyttenbach, Aurélien; Ehrenreich, David; Lovis, Christophe [Observatoire de l’Université de Genève, 51 chemin des Maillettes, CH-1290 Sauverny (Switzerland); Sing, David K., E-mail: kevin.heng@csh.unibe.ch [Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)

2015-04-10

We present a theory for interpreting the sodium lines detected in transmission spectra of exoplanetary atmospheres. Previous analyses employed the isothermal approximation and dealt only with the transit radius. By recognizing the absorption depth and the transit radius as being independent observables, we develop a theory for jointly interpreting both quantities, which allows us to infer the temperatures and number densities associated with the sodium lines. We are able to treat a non-isothermal situation with a constant temperature gradient. Our novel diagnostics take the form of simple-to-use algebraic formulae and require measurements of the transit radii (and their corresponding absorption depths) at line center and in the line wing for both sodium lines. We apply our diagnostics to the HARPS data of HD 189733b, confirm the upper atmospheric heating reported by Huitson et al., derive a temperature gradient of 0.4376 ± 0.0154 K km{sup −1}, and find densities ∼1–10{sup 4} cm{sup −3}.

The 500 deg. C isothermal section of the Gd-Tb-Co ternary system

International Nuclear Information System (INIS)

Zhou, K.W.; Zhuang, Y.H.; Li, J.Q.; Zhu, Q.M.; Deng, J.Q.

2006-01-01

The isothermal section of the phase diagram of the Gd-Tb-Co ternary system at 500 deg. C was investigated by X-ray powder diffraction, differential thermal analysis and metallographic analysis techniques. In this isothermal section, there are nine single-phase regions, eight two-phase regions and none three-phase region. No ternary compound was found. The compounds Gd 2 Co 17 and Tb 2 Co 17 , Gd 2 Co 7 and Tb 2 Co 7 , GdCo 3 and TbCo 3 , GdCo 2 and TbCo 2 , Gd 4 Co 3 and Tb 4 Co 3 , Gd 12 Co 7 and Tb 12 Co 7 , Gd 3 Co and Tb 3 Co, Gd and Tb form a continuous series of solid solutions. In addition, we experimentally determined the vertical section of pseudobinary system and the Curie temperature of Gd 1-x Tb x Co 2 (x from 0 to 1) series alloys

Fruit waste adsorbent for ammonia nitrogen removal from synthetic solution: Isotherms and kinetics

Science.gov (United States)

Zahrim, AY; Lija, Y.; Ricky, L. N. S.; Azreen, I.

2016-06-01

In this study, four types of watermelon rind (WR) adsorbents; fresh WR, modified WR with sodium hydroxide (NaOH), potassium hydroxide (KOH) and sulphuric acid (H2SO4) were used as a potential low-cost adsorbent to remove NH3-N from solution. The adsorption data were fitted with the adsorption isotherm and kinetic models to predict the mechanisms and kinetic characteristics of the adsorption process. The equilibrium data agreed well with Langmuir isotherm model with highest correlation (R2=1.00). As for kinetic modelling, the adsorption process follows pseudo-second order for all four types of adsorbents which has R2 value of 1.0 and calculated adsorption capacity, Qe of 1.2148mg/g. The calculated Qe for pseudo-second order has the smallest difference with the experimental Qe and thus suggest that this adsorption process is mainly governed by chemical process involving cations sharing or exchange between WR adsorbent and NH3-N in the solution.

Feasibility of Ericsson type isothermal expansion/compression gas turbine cycle for nuclear energy use

International Nuclear Information System (INIS)

Shimizu, Akihiko

2007-01-01

A gas turbine with potential demand for the next generation nuclear energy use such as HTGR power plants, a gas cooled FBR, a gas cooled nuclear fusion reactor uses helium as working gas and with a closed cycle. Materials constituting a cycle must be set lower than allowable temperature in terms of mechanical strength and radioactivity containment performance and so expansion inlet temperature is remarkably limited. For thermal efficiency improvement, isothermal expansion/isothermal compression Ericsson type gas turbine cycle should be developed using wet surface of an expansion/compressor casing and a duct between stators without depending on an outside heat exchanger performing multistage re-heat/multistage intermediate cooling. Feasibility of an Ericsson cycle in comparison with a Brayton cycle and multi-stage compression/expansion cycle was studied and technologies to be developed were clarified. (author)

Mise au point d'un nouvel appareil de "distillation isotherme" Disterm Development of Distherm, a New Isothermal Distillation Apparatus

Directory of Open Access Journals (Sweden)

Mouton M.

2006-11-01

Full Text Available Les études analytiques de distillats pétroliers d'intervalles d'ébullition élevés doivent être réalisées sur des produits préparés dans des conditions de distillation extrêmement douces, de manière à conserver intactes toutes les espèces chimiques initialement contenues dans le pétrole brut en l'état. Pour répondre à cet objectif, le Comité de Distillation du GEC (Groupe d'Études Concertées sur l'analyse des fractions lourdes du pétrole, réunissant Compagnie Francaise de Raffinage (CFR, Société Nationale Elf Aquitaine (SNEA et Institut Français du Pétrole (IFP a mis au point un schéma de préparation spécial de ces distillats, faisant appel à des techniques de distillation continue, de type « isotherme» et « moléculaire ». Dans ce cadre, le Comité de Distillation du GEC a été amené à développer un nouvel appareillage de distillation x isotherme », permettant de réduire, sans craquage, tout pétrole brut jusqu'à une température maximale comprise entre 350 et 380 °C. On décrit dans cet article ce nouvel ensemble de distillation, ainsi que ses conditions opératoires de fonctionnement. On y donne aussi un aperçu de la précision de la méthode de distillation réalisable avec cet appareil, ainsi que de la qualité de fractionnement obtenu.Enfin, à l'aide de quelques exemples particuliers, on montre que le domaine d'application de l'appareil peut être étendu à des produits autres que des pétroles bruts. Analytical examinations of high-boiling-range petroleum distillates must be made with products prepared under extremely mild distillation conditions so as ta maintain intact all the chemical species initially present in the original crude oil.

Exact relations for energy transfer in self-gravitating isothermal turbulence.

Science.gov (United States)

Banerjee, Supratik; Kritsuk, Alexei G

2017-11-01

Self-gravitating isothermal supersonic turbulence is analyzed in the asymptotic limit of large Reynolds numbers. Based on the inviscid invariance of total energy, an exact relation is derived for homogeneous (not necessarily isotropic) turbulence. A modified definition for the two-point energy correlation functions is used to comply with the requirement of detailed energy equipartition in the acoustic limit. In contrast to the previous relations (S. Galtier and S. Banerjee, Phys. Rev. Lett. 107, 134501 (2011)PRLTAO0031-900710.1103/PhysRevLett.107.134501; S. Banerjee and S. Galtier, Phys. Rev. E 87, 013019 (2013)PLEEE81539-375510.1103/PhysRevE.87.013019), the current exact relation shows that the pressure dilatation terms play practically no role in the energy cascade. Both the flux and source terms are written in terms of two-point differences. Sources enter the relation in a form of mixed second-order structure functions. Unlike the kinetic and thermodynamic potential energies, the gravitational contribution is absent from the flux term. An estimate shows that, for the isotropic case, the correlation between density and gravitational acceleration may play an important role in modifying the energy transfer in self-gravitating turbulence. The exact relation is also written in an alternative form in terms of two-point correlation functions, which is then used to describe scale-by-scale energy budget in spectral space.

Analysis of the interactions between human serum albumin/amphiphilic penicillin in different aqueous media: an isothermal titration calorimetry and dynamic light scattering study

International Nuclear Information System (INIS)

Barbosa, Silvia; Taboada, Pablo; Mosquera, Victor

2005-01-01

The complexation process of the amphiphilic penicillins sodium cloxacillin and sodium dicloxacillin with the protein human serum albumin (HSA) in aqueous buffered solutions of pH 4.5 and 7.4 at 25 o C was investigated through isothermal titration calorimetry (ITC) and dynamic light scattering. ITC experiments were carried out in the very dilute regime and showed that although hydrophobic interactions are the leading forces for complexation, electrostatic interactions also play an important role. The possibility of the formation of hydrogen bonds is also deduced from experimental data. The thermodynamic quantities of the binding mechanism, i.e, the enthalpy, ΔHITCi, entropy, ΔSITCi, Gibbs energy, ΔGITCi, binding constant, KITCi and the number of binding sites, n i , were obtained. The binding was saturable and is characterised by Langmuir adsorption isotherms. From ITC data and following a theoretical model, the number of bound and free penicillin molecules was calculated. From Scatchard plots, KITCi and n i were obtained and compared with those from ITC data. The interaction potential between the HSA-penicillin complexes and their stability were determined at pH 7.4 from the dependence of the diffusion coefficients on protein concentration by application of the DLVO colloidal stability theory. The results indicate decreasing stability of the colloidal dispersion of the drug-protein complexes with increase in the concentration of added drug

Thermal degradation and isothermal crystalline behavior of poly(trimethylene terephthalate)

Institute of Scientific and Technical Information of China (English)

Jian Liu; Shu Guang Bian; Min Xiao; Shuan Jin Wang; Yue Zhong Meng

2009-01-01

Poly(trimethylene terephthalate)(PTT)is an excellent fiber material.Its thermal degradation and isothermal crystalline behaviors were in this study investigated using thermogravimetric analysis(TGA),thermogravimetric analysis-Fourier transform infrared spectroscopy(TGA-FTIR)analysis,differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The thermal degradation mechanism of PTT follows Mclafferty rearrangement principle.The PTT with intrinsicviscosity(IV)of 0.74 dL/g has a maximum crystallinity of about 55%at 190℃,as demonstrated by DSC and XRD measurements consistently.

Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) Using Simultaneous Detection of mecA, nuc, and femB by Loop-Mediated Isothermal Amplification (LAMP).

Science.gov (United States)

Chen, Changguo; Zhao, Qiangyuan; Guo, Jianwei; Li, Yanjun; Chen, Qiuyuan

2017-08-01

The aim of this study was to develop a rapid detection assay to identify methicillin-resistant Staphylococcus aureus by simultaneous testing for the mecA, nuc, and femB genes using the loop-mediated isothermal amplification (LAMP) method. LAMP primers were designed using online bio-software ( http://primerexplorer.jp/e/ ), and amplification reactions were performed in an isothermal temperature bath. The products were then examined using 2% agarose gel electrophoresis. MecA, nuc, and femB were confirmed by triplex TaqMan real-time PCR. For better naked-eye inspection of the reaction result, hydroxy naphthol blue (HNB) was added to the amplification system. Within 60 min, LAMP successfully amplified the genes of interest under isothermal conditions at 63 °C. The results of 2% gel electrophoresis indicated that when the Mg 2+ concentration in the reaction system was 6 μmol, the amplification of the mecA gene was relatively good, while the amplification of the nuc and femB genes was better at an Mg 2+ concentration of 8 μmol. Obvious color differences were observed by adding 1 μL (3.75 mM) of HNB into 25 μL reaction system. The LAMP assay was applied to 128 isolates cases of methicillin-resistant Staphylococcus aureus, which were separated from the daily specimens and identified by Vitek microbial identification instruments. The results were identical for both LAMP and PCR. LAMP offers an alternative detection assay for mecA, nuc, and femB and is faster than other methods.