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1

Dissolution Methods Database  

Center for Drug Evaluation (CDER)

... For a drug product that does not have a dissolution test method in the United States Pharmacopeia (USP), the FDA Dissolution Methods Database ... More results from www.fda.gov/drugs/informationondrugs

2

Vibration effects of lab equipment on dissolution testing with USP paddle method.  

PubMed

Environmental vibration induced by laboratory equipment, building construction, or even by the analysts themselves is one of the more complicated factors affecting dissolution testing. It is difficult to control and/or calibrate by mechanical means or performance-based methods. In this study, dissolution apparatus vibration levels were measured in the frequency range from 10 to 270 Hz along all three axes using commercially available, single-axis accelerometers. The vibration distribution on the dissolution vessel plate was mapped, and acceleration was subsequently measured during dissolution runs involving NCDA#2 (10 mg prednisone) tablets using the paddle method. Several types of laboratory equipment were used to induce vibration during dissolution testing and vibration levels along the X-, Y-, and Z-axes of the vessel plate were measured in an attempt to establish possible correlation with dissolution results. In the frequency range studied, root mean square (RMS) acceleration values above 0.01 g, in either vertical or horizontal direction, typically affected dissolution results. PMID:19544371

Gao, Zongming; Thies, Andrea; Doub, William

2010-01-01

3

Chemometric and derivative methods as flexible spectrophotometric approaches for dissolution and assaying tests in multicomponent tablets.  

PubMed

Two derivative spectrophotometric (ratio derivative spectra and algorithm bivariate calibration) and a chemometric methods (partial least squares, PLS) are proposed for the simultaneous determination of binary mixtures in tablet analysis and dissolutions tests, without prior separation. These approaches are successfully applied to quantify trimethoprim (TMP) combined with sulfamethoxazole (SMX) or sulfamethazine (SMZ) or sulfafurazole (SFZ) using the information in the absorption spectra of appropriate solutions. Beer's law was obeyed in the concentration range of 0.98-17.5 microg/ml for TMP, 0.95-17.2 microg/ml for SMX, 1.16-17.5 microg/ml for SMZ and 0.97-17.4 microg/ml for SFZ. The first derivative (1D) bivariate algorithm method involves the use of four calibration curves: two for each compound at two different wavelengths, selected by Kaiser's method. Similarly, the first derivative ratio spectrophotometry employs the linear relationship between the ratio spectra of the analytes and the concentration range. The results were compared with those obtained by PLS multivariate calibration. The calibration models from PLS were pre-treated by orthogonal signal correction and evaluated by cross-validation using the 'SIMCA-P 9' software. Synthetic mixtures of TMP and sulfonamides were used in five different sets for the validity of the calibrations. Mean recoveries for derivative ratio, derivative bivariate and PLS methods were found to be between 99.7% and 102.0% for TMP, 99.4% and 100.2% for SMX, 99.3% and 101.0% for SMZ and 98.1% and 102.3% for SFZ. The calibrations of the three methods were successfully applied to the assaying and dissolution of placebo and commercial tablets without any prior separation. More than 85% of TMP, SMX and SMZ were dissolved within 15 min. For SFZ, only 85% of the compound was dissolved after 60 min. In this study, the three spectrophotometric methods can be satisfactorily used for the quantitative analysis and for dissolution tests of multicomponent dosage forms. PMID:15262532

Markopoulou, Catherine K; Malliou, Eleftheria T; Koundourellis, John E

2004-08-01

4

Self-modeling curve resolution method applied for the evaluation of dissolution testing data: a case study of meloxicam-mannitol binary systems.  

PubMed

This paper introduces some chemometric methods, i.e., self-modeling curve resolution (SMCR), multivariate curve resolution-alternating least squares (MCR-ALS) and parallel factor analysis (PARAFAC and PARAFAC2), which are used to evaluate in vitro dissolution testing data detected by a UV-vis spectrophotometer on meloxicam-mannitol binary systems. These systems were chosen because of their relative simplicity to apply as part of the validation process illustrating the effectiveness of the developed and applied chemometric method. The paper illustrates the failure of PARAFAC methods used before for pharmaceutical data evaluations as well, and we suggest application of the feasible band form given by SMCR as a more general procedure. Steps to improve the dissolution behavior of drugs have become among the most interesting aspects of pharmaceutical technology, and our results show that a larger particle size of meloxicam is advantageous for dissolution. Instead of the use of only one characteristic wavelength, appropriate chemometric methods can furnish more information from dissolution testing data, i.e., the individual dissolution rate profiles and the individual spectra for all the components can be obtained without resorting to any separation techniques such as HPLC. PMID:19559876

Rajkó, Róbert; Nassab, Parya Reisi; Szabó-Révész, Piroska

2009-04-09

5

Hydrodynamic, mass transfer, and dissolution effects induced by tablet location during dissolution testing.  

PubMed

Tablets undergoing dissolution in the USP Dissolution Testing Apparatus II are often found at locations on the vessel bottom that are off-center with respect to the dissolution vessel and impeller. A previously validated CFD approach and a novel experimental method were used here to examine the effect of tablet location on strain rates and dissolution rates. Dissolution tests were conducted with non-disintegrating tablets (salicylic acid) and disintegrating tablets (Prednisone) immobilized at different locations along the vessel bottom. CFD was used to predict the velocity profiles and strain rates when the tablets were placed at such locations. A CFD-based model was derived to predict the mass transfer coefficient and dissolution curves, which were then compared to the experimental results. Both non-disintegrating and disintegrating off-center tablets experimentally produced higher dissolution rates than centered tablets. The CFD-predicted strain rate distribution along the bottom was highly not uniform and the predicted strain rates correlated well with the experimental mass transfer coefficients. The proposed CFD-based model predicts mass transfer rates that correlate well with the experimental ones. The exact tablet location has a significant impact on the dissolution profile. The proposed model can satisfactorily predict the mass transfer coefficients and dissolution profiles for non-disintegrating tablets. PMID:18781589

Bai, Ge; Armenante, Piero M

2009-04-01

6

Dissolution test acceptance sampling plans  

Microsoft Academic Search

The U.S. Pharmacopeia (USP) general monograph provides a standard for dissolution compliance with the requirements as stated in the individual USP monograph for a tablet or capsule dosage form. The acceptance rules recommended by USP have important roles in the quality control process. The USP rules and their modifications are often used as an industrial lot release sampling plan, where

Yi Tsong; Thomas Hammerstrom; Karl Lin; Ting Eng Ong

1995-01-01

7

Bench Scale Saltcake Dissolution Test Report  

SciTech Connect

A potential scenario for retrieving saltcake from single shell tanks is the ''Rainbird{reg_sign} sprinkler'' method. Water is distributed evenly across the surface of the saltcake and allowed to percolate by gravity through the waste. The salt dissolves in the water, forming a saturated solution. The saturated liquid is removed by a saltwell pump situated near the bottom of the tank. By this method, there is never a large inventory of liquid in the tank that could pose a threat of leakage. There are many variables or factors that can influence the hydrodynamics of this retrieval process. They include saltcake porosity; saltwell pumping rate; salt dissolution chemistry; factors that could promote flow channeling (e.g. tank walls, dry wells, inclusions or discontinuities in the saltcake); method of water distribution; plug formation due to crystal formations or accumulation of insoluble solids. A brief literature search indicates that very little experimental data exist on these aspects of saltcake dissolution (Wiersma 1996, 1997). The tests reported here were planned (Herting, 2000) to provide preliminary data and information for planning future, scaled-up tests of the sprinkler method.

BECHTOLD, D.B.; PACQUET, E.A.

2000-12-06

8

Dissolution testing of orally disintegrating tablets.  

PubMed

For industrially manufactured pharmaceutical dosage forms, product quality tests and performance tests are required to ascertain the quality of the final product. Current compendial requirements specify a disintegration and/or a dissolution test to check the quality of oral solid dosage forms. These requirements led to a number of compendial monographs for individual products and, at times, the results obtained may not be reflective of the dosage form performance. Although a general product performance test is desirable for orally disintegrating tablets (ODTs), the complexity of the release controlling mechanisms and short time-frame of release make such tests difficult to establish. For conventional oral solid dosage forms (COSDFs), disintegration is often considered to be the prerequisite for subsequent dissolution. Hence, disintegration testing is usually insufficient to judge product performance of COSDFs. Given the very fast disintegration of ODTs, the relationship between disintegration and dissolution is worthy of closer scrutiny. This article reviews the current status of dissolution testing of ODTs to establish the product quality standards. Based on experimental results, it appears that it may be feasible to rely on the dissolution test without a need for disintegration studies for selected ODTs on the market. PMID:22686339

Kraemer, Johannes; Gajendran, Jayachandar; Guillot, Alexis; Schichtel, Julian; Tuereli, Akif

2012-04-08

9

Dissolution testing of amorphous solid dispersions.  

PubMed

The main purpose of this study was to investigate the effect of different polymers, with varying physicochemical properties and molecular weight on the stability and dissolution of co-milled amorphous solid dispersions (ASDs) of piroxicam (PRX). The stability of amorphous PRX (aPRX) in ASDs was significantly improved by the polymers. In-line Raman spectroscopy revealed that solvent mediated solid state changes occurred in biorelevant medium, however differences between ASDs were found. Thus, the dissolution behavior of ASDs of PRX and the respective polymer during conventional large volume (900ml) and a commercial small volume (20ml) dissolution testing was evaluated. The results of these studies indicated that the molecular weight of the polymer (PVP90 vs PVP25) is influencing the solubility of PRX from ASD. Interestingly the effect of molecular weight of the polymer was different than reported previously in the literature for the similar ASDs prepared by spray drying. Furthermore, the dose related bioavailability was determined by investigating the experimental saturation concentrations for different doses. These studies confirmed the findings of the dissolution studies. The differences are presumably caused by the formation of physically different diffusion layers around the ASD particles. PMID:23370435

Kogermann, K; Penkina, A; Predbannikova, K; Jeeger, K; Veski, P; Rantanen, J; Naelapää, K

2013-01-28

10

21 CFR 343.90 - Dissolution and drug release testing.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Dissolution and drug release testing. 343.90... Testing Procedures § 343.90 Dissolution and drug release testing. (a...capsules. Aspirin capsules must meet the dissolution standard for aspirin capsules as...

2009-04-01

11

21 CFR 343.90 - Dissolution and drug release testing.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Dissolution and drug release testing. 343.90... Testing Procedures § 343.90 Dissolution and drug release testing. (a...capsules. Aspirin capsules must meet the dissolution standard for aspirin capsules as...

2010-04-01

12

An inferential procedure for the probability of passing the USP dissolution test.  

PubMed

Dissolution is one of the tests that is required and specified by the United States Pharmacopeia and National Formulary (USP/NF) to ensure that the drug products meet the standards of the identity, strength, quality, purity, and stability. The sponsors also establish the in-house specifications for the mean and standard deviation of the dissolution rates to guarantee a high probability of passing the USP/NF dissolution test. However, the USP/NF dissolution test is a complicated three-stage sampling plan that involves both the sample mean dissolution rate of all units and the dissolution rate of individual units. It turns out that the true probability of passing the USP/NF dissolution is formidable to compute analytically even when the population mean and variance of dissolution rates are known. It is not clear that previously proposed methods are the estimators of the true probability for passing the USP dissolution test. Therefore, we propose to employ a parametric bootstrap method in conjunction with the Monte Carlo simulation to obtain the sampling distribution of the estimated probabilities of passing the USP/NF dissolution test and hence the confidence interval for the passing probability. In addition, a procedure is proposed to test whether the true probability of passing the USP/NF dissolution test is greater than some specified value. A numerical example illustrates the proposed method. Copyright © 2011 John Wiley & Sons, Ltd. PMID:21506255

Chiang, Chieh; Chen, Chen-Fang; Huang, Meng-Yang; Liu, Jen-Pei

2011-04-20

13

Characterization and Dissolution Kinetics Testing of Radioactive H-3 Calcine  

SciTech Connect

Characterization and dissolution kinetics testing were performed with Idaho radioactive H-3 calcine. Calcine dissolution is the key front-end unit operation for the Separations Alternative identified in the Idaho High Level Waste Draft EIS. The impact of the extent of dissolution on the feasibility of Separations must be clearly quantified.

Garn, Troy Gerry; Batcheller, Thomas Aquinas

2002-09-01

14

Long Term Dissolution Testing of Mine Waste.  

National Technical Information Service (NTIS)

This document reports the results of long term laboratory studies to examine the dissolution of abandoned mine wastes and the consequent drainage quality. The objectives of the study were to provide a description of longer term dissolution of mine wastes,...

K. Lapakko J. Wessels D. Antonson

1995-01-01

15

Dissolution of low burnup Fast Flux Test reactor fuel  

Microsoft Academic Search

The first Fast-Flux Test Facility reactor fuel (mixed (U,Pu)Oâ composition) has been used in dissolution tests for fuel reprocessing. The fuel tested here had a peak burnup of 0.22 at. %, with peak centerline temperatures of 1997°C. Linear dissolution rates of 0.99 to 1.57 mm\\/h were determined for dissolver solution and fresh acid, respectively. Insoluble residues from dissolution at 95°C

R. L. Fellows; D. O. Campbell; J. C. Mailen

1984-01-01

16

The random vibration effects on dissolution testing with USP apparatus 2.  

PubMed

Dissolution testing is of primary importance for optimization of drug formulation and quality control, but test results typically show large variability. Vibration is one of the factors that can increase variability of dissolution testing. In this study, a Distek USP Apparatus 2 was used to perform dissolution testing using disintegrating 10 mg prednisone tablets at 50 rpm in 500 mL of 37 degrees C degassed water medium. A controllable vertical random vibration was applied to the dissolution apparatus during the dissolution testing. Real-time vibration waveforms were recorded using accelerometers placed at various locations on the vessel plate and on the dissolution vessels. Preliminary results showed a strong correlation between induced vibration and dissolution results. The vibration measured on the vessel plate correlates well with that measured within nearby vessels. The observed dissolution profiles suggest that vibration affects the disintegration and dissolving processes by different mechanisms, leading to high or low results depending upon during which phase of the dissolution process the vibration occurs. This study also presents a method capable of measuring vibration in a meaningful manner and how to determine where best to measure it. PMID:18399543

Gao, Zongming; Moore, Terry W; Buhse, Lucinda F; Doub, William H

2009-01-01

17

[Evaluation of dissolution of osmotic-controlled release paliperidone tablets using the reciprocating cylinder method].  

PubMed

The dissolution profiles of paliperidone from INVEGA(®) 3-mg tablets, osmotic-controlled release tablets, were evaluated by using the reciprocating cylinder method (RC method). We used 4 different compositions of the dissolution fluids, by considering the environment of the tablet in the gastrointestinal tract. After a lag time of 2 to 4 h, paliperidone was approximately dissolved to 24 h by zero-order release. The dissolution characteristics of paliperidone were not affected by the kind of the test medium, pH, and surfactant. In addition, the dissolution of the tablets was evaluated using the paddle method in distilled water, Japanese Pharmacopeia (JP) 1st test fluid, and JP 2nd test fluid. The dissolution profiles of paliperidone obtained using the RC method and the paddle method were very similar. Further, the dispersion of the percentage of the dissolved paliperidone obtained using the RC method and the paddle method was small. PMID:23257415

Nagata, Shunji; Jin-nai, Aya; Hirai, Ken-ichi; Baba, Mikako; Higashi, Kousuke; Tanaka, Yusuke

2012-12-21

18

Vibration effects on dissolution tests with USP apparatuses 1 and 2.  

PubMed

Dissolution testing is of primary importance for drug formulation and quality control. Many sources of variability are accounted for in the apparatus' mechanical calibration process; the effect of vibration on dissolution tests is not well understood in that the test's tolerance for environmental vibration with respect to magnitude or frequency is largely unknown. In this study, USP Apparatuses 1 and 2 were used. Dissolution profiles were obtained for both disintegrating and nondisintegrating tablets. In separate experiments, a lab vacuum pump or a lab mixer, both commonly used in laboratories, was used to generate vibration during dissolution runs with vibration parameters being recorded at a location close to the dissolution vessels. Disintegrating tablets were found to be sensitive to induced vibrations with both the paddle and basket methods. Average dissolution results for nondisintegrating tablets were not sensitive to the studied vibrations; however, variability of the results increased in some cases. The dissolution profiles suggest that the vibration effects on paddle and basket method occur through different mechanisms. The importance of vibration to dissolution test results depends on the vibration source, product being tested and the apparatus type. PMID:18000813

Gao, Zongming; Moore, Terry W; Doub, William H

2008-08-01

19

Long Term Dissolution Testing of Mine Waste: Appendices.  

National Technical Information Service (NTIS)

This document contains the appendices for the long term laboratory studies to examine the dissolution of abandoned mine wastes and the consequent drainage quality. Appendices include solid phase characterization, wet-dry cycle test, elevated temperature t...

K. Lapakko J. Wessels D. Antonson

1995-01-01

20

Dissolution test for low-activity waste product acceptance.  

SciTech Connect

We have measured the mean and standard deviation of the solution concentrations of B, Na, and Si attained in replicate dissolution tests conducted at temperatures of 20, 40, and 70 C, for durations of 3 and 7 days, and at glass/water mass ratios of 1:10 and 1:1. These and other tests were conducted to evaluate the adequacy of the test methods specified in privatization contracts and to develop a data base that can be used to evaluate the reliability of reported results for tests performed on the waste products. Tests were conducted with a glass that we formulated to be similar to low-activity waste products that will be produced during the remediation of Hanford tank wastes. Statistical analyses indicated that, while the mean concentrations of B, Na, and Si were affected by the values of test parameters, the standard deviation of replicate tests was not. The precision of the tests was determined primarily by uncertainties in the analysis of the test solutions. Replicate measurements of other glass properties that must be reported for Hanford low-activity waste products were measured to evaluate the possible adoption of the glass used in these tests as a standard test material for the product acceptance process.

Ebert, W. L.

1998-05-20

21

A novel off-center paddle impeller (OPI) dissolution testing system for reproducible dissolution testing of solid dosage forms.  

PubMed

Dissolution testing is routinely conducted in the pharmaceutical industry to provide in vitro drug release information for quality control purposes. The most common dissolution testing system for solid dosage forms is the United States Pharmacopeia (USP) Dissolution Testing Apparatus 2. This apparatus is very sensitive to the initial location of the tablet, which cannot be controlled because the tablet is dropped into the vessel at the beginning of the test and it may rest at random locations at the vessel's bottom. In this work, a modified Apparatus 2 in which the impeller was placed 8?mm off center in the vessel was designed and tested. This new design was termed "OPI" for "off-center paddle impeller." Dissolution tests were conducted with the OPI apparatus for nine different tablet locations using both disintegrating tablets (prednisone) and nondisintegrating tablets (salicylic acid). The dissolution profiles in the OPI apparatus were largely independent of the tablet location at the vessel's bottom, whereas those obtained in the Standard System generated statistically different profiles depending on the tablet location. The newly proposed OPI system can effectively eliminate artifacts generated by random settling of the tablet at the vessel's bottom, thus making the test more robust. PMID:22083630

Wang, Yimin; Armenante, Piero M

2011-11-14

22

Glass Dissolution: Testing and Modeling for Long-Term Behavior.  

SciTech Connect

The basic concepts of thermodynamics and kinetics are discussed in relationship to glass dissolution testing. While it seems like these subjects are too basic to be discussed in a journal article, it is often the case that we forget these concepts when planning and designing dissolution tests and interpreting the results that come from these tests. The possible connection between the composition of the dissolving glass and its long-term behavior is discussed. Results from a preliminary study suggest that the aluminum content of a glass is important to its long-term behavior. The formation of a zeolite can cause the glass dissolution rate to increase under certain conditions that can be modeled. Results indicate that complex glasses can be modeled with a glass containing as little as six components.

Strachan, Denis M. (BATTELLE (PACIFIC NW LAB))

2001-09-01

23

Dissolution of low burnup Fast Flux Test reactor fuel  

SciTech Connect

The first Fast-Flux Test Facility reactor fuel (mixed (U,Pu)O/sub 2/ composition) has been used in dissolution tests for fuel reprocessing. The fuel tested here had a peak burnup of 0.22 at. %, with peak centerline temperatures of 1997/sup 0/C. Linear dissolution rates of 0.99 to 1.57 mm/h were determined for dissolver solution and fresh acid, respectively. Insoluble residues from dissolution at 95/sup 0/C ranged from 0.18 to 0.28% of the original fuel. From 2 to 37 wt % of the residue was recoverable plutonium. Dissolution at 29/sup 0/C yielded residues of 0.56 to 0.64% of the original fuel. The major elements present in the HF leached residue included Ru, Mo, and Rh. The recovered cladding from the 95/sup 0/C dissolution contained the equivalent of 198 mg of /sup 239/Pu per 100 g of hulls, while the cladding from the 29/sup 0/c experiments contained only 0.21 mg of /sup 239/Pu per 100 g of hulls. 9 references, 5 figures.

Fellows, R.L.; Campbell, D.O.; Mailen, J.C.

1984-01-01

24

Development and validation of a dissolution test for meloxicam and pridinol mesylate from combined tablet formulation.  

PubMed

The association of meloxicam and pridinol is indicated for treating muscular contractures and low back pain. A dissolution test for the meloxicam-pridinol combined tablet formulation was developed and validated, using a suitable HPLC method for simultaneously quantitating both dissolved drugs. The optimized conditions include the use of USP apparatus 2 at a paddle rotation rate of 75 rpm and 900 ml of 50 mM phosphate buffer (pH= 7.5) as dissolution medium, at 37.0±0.5°. The test, which demonstrated to be robust against small changes in bath temperature, paddle rotation speed and pH of the dissolution medium, was applied to two different brands of tablets; the corresponding dissolution profiles were constructed and both brands showed to dissolve at least 75% of the drugs at the 45 min time point. PMID:20838523

Vignaduzzo, S E; Castellano, P M; Kaufman, T S

2010-03-01

25

Powder Dissolution Method for Estimating Rotating Disk Intrinsic Dissolution Rates of Low Solubility Drugs  

Microsoft Academic Search

Purpose  The objective was to investigate the applicability and limitations of a novel approach for measuring intrinsic dissolution\\u000a rates (IDR) of very small quantities of compounds introduced as powders to buffered solutions and comparing these results\\u000a to disk IDR obtained using the traditional Wood’s apparatus.\\u000a \\u000a \\u000a \\u000a Methods  The powder dissolution profiles of 13 model drugs were determined at 37°C in USP buffers at

Konstantin Tsinman; Alex Avdeef; Oksana Tsinman; Dmytro Voloboy

2009-01-01

26

Designing biorelevant dissolution tests for lipid formulations: Case example – Lipid suspension of RZ-50  

Microsoft Academic Search

Biorelevant dissolution test methods for lipid formulations of RZ-50, an experimental Roche compound, were developed and compared with standard compendial methods in terms of their in vivo predictability. Release of RZ-50, a poorly soluble weakly acidic drug, from lipid suspensions filled in soft gelatin capsules was studied in compendial and biorelevant media using the USP Apparatus 2 (paddle method) and

Ekarat Jantratid; Niels Janssen; Hitesh Chokshi; Kin Tang; Jennifer B. Dressman

2008-01-01

27

Change in criteria for USP dissolution performance verification tests.  

PubMed

The US Pharmacopeial Convention has been evaluating its performance verification tests (PVT) for several years. These tests help ensure the integrity of the US Pharmacopeia performance test when a dissolution procedure, as described in General Chapter Dissolution <711>, is relied upon to test a nonsolution orally administered dosage form. One result of the evaluation is a change in the PVT criterion from one based on individual tablet results to one based on the mean and variability of a set of tablets. This paper describes the new PVT and its criterion and how its acceptance limits are derived from results of a collaborative study, explains a two-stage option for the test, and presents operating characteristics. PMID:19132536

Hauck, Walter W; DeStefano, Anthony J; Brown, William E; Stippler, Erika S; Abernethy, Darrell R; Koch, William F; Williams, Roger L

2009-01-09

28

Test Objectives for the Saltcake Dissolution Retrieval Demonstration  

SciTech Connect

This document describes the objectives the Saltcake Dissolution Retrieval Demonstration. The near term strategy for single-shell tank waste retrieval activities has shifted from focusing on maximizing the number of tanks entered for retrieval (regardless of waste volume or content) to a focus on scheduling the retrieval of wastes from those single-shell tanks with a high volume of contaminants of concern. These contaminants are defined as mobile, long-lived radionuclides that have a potential of reaching the groundwater and the Columbia River. This strategy also focuses on the performance of key retrieval technology demonstrations, including the Saltcake Dissolution Retrieval Demonstration, in a variety of waste forms and tank farm locations to establish a technical basis for future work. The work scope will also focus on the performance of risk assessment, retrieval performance evaluations (RPE) and incorporating vadose zone characterization data on a tank-by-tank basis, and on updating tank farm closure/post closure work plans. The deployment of a retrieval technology other than Past-Practice Sluicing (PPS) allows determination of limits of technical capabilities, as well as, providing a solid planning basis for future SST retrievals. This saltcake dissolution technology deployment test will determine if saltcake dissolution is a viable retrieval option for SST retrieval. CH2M Hill Hanford Group (CHG) recognizes the SST retrieval mission is key to the success of the River Protection Project (RPP) and the overall completion of the Hanford Site cleanup. The objectives outlined in this document will be incorporated into and used to develop the test and evaluation plan for saltcake dissolution retrievals. The test and evaluation plan will be developed in fiscal year 2001.

DEFIGH PRICE, C.

2000-09-22

29

Interlaboratory study of the reproducibility of the single-pass flow-through test method : measuring the dissolution rate of LRM glass at 70 {sup {degree}}C and pH 10.  

SciTech Connect

An international interlaboratory study (ILS) was conducted to evaluate the precision with which single-pass flow-through (SPFT) tests can be conducted by following a method to be standardized by the American Society for Testing and Materials - International. Tests for the ILS were conducted with the low-activity reference material (LRM) glass developed previously for use as a glass test standard. Tests were conducted at 70 {+-} 2 C using a LiCl/LiOH solution as the leachant to impose an initial pH of about 10 (at 70 C). Participants were provided with LRM glass that had been crushed and sieved to isolate the -100 +200 mesh size fraction, and then washed to remove fines. Participants were asked to conduct a series of tests using different solution flow rate-to-sample mass ratios to generate a range of steady-state Si concentrations. The glass dissolution rate under each test condition was calculated using the steady-state Si concentration and solution flow rate that were measured in the test. The glass surface area was estimated from the mass of glass used in the test and the Si content of LRM glass was known. A linear relationship between the rate and the steady-state Si concentration (at Si concentrations less than 10 mg/L) was used to estimate the forward dissolution rate, which is the rate in the absence of dissolved Si. Participants were asked to sample the effluent solution at least five times after reaction times of between 3 and 14 days to measure the Si concentration and flow rate, and to verify that steady-state was achieved. Results were provided by seven participants and the data sets provided by five participants were sufficient to determine the forward rates independently.

Ebert, W. L.; Chemical Engineering

2006-02-28

30

Development of Alkaline Oxidative Dissolution Methods for Chromium (III) Compounds Present in Hanford Site Tank Sludges  

SciTech Connect

The high-level radioactive waste sludge in the underground storage tanks at the Hanford Site contains various chromium(III)solid phases. Dissolution and removal of chromium from tank waste sludges is desirable prior to high-level waste vitrification because increased volume is required to incorporate the residual chromium. Unfortunately, dissolution of chromium from the sludge to form Cr(OH){sub 4}{sup {minus}} through treatment with heated NaOH solution (also used to dissolve aluminum phases and metathesize phosphates to sodium salts) generally has been unsuccessful in tests with both simulated and genuine Hanford waste sludges. Oxidative dissolution of the Cr(III) compounds to form soluble chromate has been proposed as an alternative chromium solid phase dissolution method and results of limited prior testing have been reported.

NN Krot; VP Shilov; AM Fedoseev; NA Budantseva; MV Nikonov; AB Yusov; AYu Garnov; IA Charushnikova; VP Perminov; LN Astafurova; TS Lapitskaya; VI Makarenkov

1999-07-02

31

Guidance for Industry: Dissolution Testing of Immediate Release Solid Oral Dosage Forms.  

National Technical Information Service (NTIS)

This guidance is developed for immediate release (IR) dosage forms and is intended to provide (1) general recommendations for dissolution testing; (2) approaches for setting dissolution specifications related to the biopharmaceutic characteristics of the ...

1997-01-01

32

The dissolution efficiency for different stream liming methods  

Microsoft Academic Search

The dissolution efficiency for different stream liming methods is shown to depend upon the following parameters: Particle size distribution; Initial pH-value; Dose intensity; and Degree of wet slurrying. The particle size distribution and the degree of wet slurrying are the only free variables and when they are determined, the others are determined by the conditions at the dosing site. The

H. U. Sverdrup

1986-01-01

33

Comparison of dissolution profiles obtained from nifedipine extended release once a day products using different dissolution test apparatuses  

Microsoft Academic Search

In order to improve the predictability of dissolution testing new apparatuses have been proposed that mimic hydrodynamic and mechanical conditions in the gastrointestinal tract. In this study tested were four different nifedipine extended release (ER) formulations using the paddle apparatus and the reciprocating cylinder as pharmacopoeial test devices as well as two newly developed test apparatuses: the rotating beaker apparatus

Grzegorz Garbacz; Berit Golke; Ralph-Steven Wedemeyer; Marie Axell; Erik Söderlind; Bertil Abrahamsson; Werner Weitschies

2009-01-01

34

DISSOLUTION METHOD OF REMOVING BONDING AGENTS  

DOEpatents

A method is given for removing residual aluminumsilicon bonding agents from uranium slugs after the removal of aluminum coatings. To accomplish this the slug is immersed in an aqueous solution about 0.75 N in hydrofluoric acid and about 7 N in nitric acid.

Hyman, H.H.

1960-04-19

35

Characterization Plan and Dissolution Tests for Tank 16H Samples  

SciTech Connect

In support of the closure of Tank 16H, a sample of the solids residue on the bottom of the tank interior and three samples from the tank annulus will be sent to SRTC for analysis. The results of the analysis of the samples from the tank interior and the annulus will define the source term inventory used for fate and transport modeling. In addition, the samples from the tank annulus will be used for dissolution tests to evaluate the effectiveness of various cleaning alternatives.

Davis, P.L.; Hay, M.S.

1998-02-09

36

Dissolution study of nanocrystal powders of a poorly soluble drug by UV imaging and channel flow methods.  

PubMed

Application of drug nanocrystals provides advantageous options for the pharmaceutical formulation development of poorly soluble drugs. The objective of this study was to investigate the dissolution behavior improving effects of differently sized nanocrystals of a poorly soluble model drug, indomethacin. Nanocrystal suspensions were prepared using a top-down wet milling technique with three stabilizers: poloxamer F68, poloxamer F127 and polysorbate 80. The dissolution of the differently sized indomethacin nanocrystals were investigated using a channel flow dissolution method and by UV imaging. Unmilled bulk indomethacin and physical mixtures were used as references. According to both the dissolution methods, the dissolution properties of indomethacin were improved by the particle size reduction. UV imaging was used for the first time as a dissolution testing method for fast dissolving nanoscale material. The technique provided new information about the concentration of the dissolved drug next to the sample surface; with the smallest nanocrystals (580nm) the indomethacin concentration next to the particle surface exceeded five-fold the thermodynamic saturated indomethacin solution concentration. Thus the solubility improvement itself, not only the increased surface area for dissolution, may have an important role in the higher dissolution rates of nanocrystal formulations. Poloxamer F68 was the most optimal stabilizer in the preparation of the indomethacin nanocrystal suspensions and in the solubility and dissolution enhancement as well. PMID:23999036

Sarnes, Annika; Ostergaard, Jesper; Jensen, Sabrine Smedegaard; Aaltonen, Jaakko; Rantanen, Jukka; Hirvonen, Jouni; Peltonen, Leena

2013-08-30

37

Self-reference chemical profiling in the comprehensive dissolution test of herbal medicines.  

PubMed

The power of chemical profiling in characterizing the samples' chemical pools has greatly raised the interests of phytomedicine researchers. Unfortunately, the semi-quantitative nature of chemical profiling retards its exploration into the dissolution test of herbal medicines, which is a crucial quantitative measure to evaluate and control the in vitro releasing properties as the prerequisite for biomembrane permeation of herbal constituents. Here, a method integrating chemical profiling approach and self-reference strategy is developed for the purpose of dissolution test of herbal medicines. The chromatographic fingerprints of the self-reference samples are translated by principal component analysis (PCA) into chemical profiles that highly correlate to their nominal gross concentrations in spite of the poor quantitative performances of some individual peaks. Pareto scaling previous to PCA selectively highlights the relative loadings of peaks with good quantitative performances. An example of ginkgo biloba tablets shows that this method is efficient to judge whether the detected constituents are simultaneously released or not, determine both the gross release and the respective dissolution rates of them, and rapidly screen the slowly released ones that may have potential clinical implications. This method has potentials to enable deep insight into the molecular diffusion and dissolution of complex herbal formulations, and open a new window to comprehensively consider the bioavailable properties of herbal medicines. PMID:22748665

Wang, Anqi; Wang, Zhanguo; Yu, Wenjun; Zhong, Ting; Dai, Weiyang; Xu, Liang; Gong, Tao; Lan, Ke

2012-06-12

38

Use and Limitations of In Vitro Dissolution Testing: Topic ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... to precipitation Bile salt solubility ... lumen Formulation dispersion, dissolution and drug precipitation Formulation development ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

39

MRI studies of the hydrodynamics in a USP 4 dissolution testing cell.  

PubMed

We present a detailed study of hydrodynamics inside the flow-through dissolution apparatus when operated according to USP recommendations. The pulsatile flow inside the flow-through cell was measured quantitatively using magnetic resonance imaging (MRI) at a spatial resolution of 234 × 234 ?m(2) and slice thickness of 1 mm. We report the experimental protocols developed for in situ MRI studies and the effect that the operating conditions and tablet orientation have on the hydrodynamics inside commercial flow cells. It was found that the flow field inside the dissolution cells was, at most operating conditions, heterogeneous, rather than fully developed laminar flow, and characterised by re-circulation and backward flow. A model tablet was shown to be contacted by a wide distribution of local velocities as a function of position and orientation in the flow cell. The use of 1 mm beads acted as a distributor of the flow but did not suffice to ensure a fully developed laminar flow profile. These results emphasise the necessity to understand the influence of test conditions on dissolution behaviour in defining robust flow-through dissolution methods. PMID:20949631

Shiko, G; Gladden, L F; Sederman, A J; Connolly, P C; Butler, J M

2010-10-14

40

Measurement of Dissolved Oxygen as a Determination of Media Equilibrium During Dissolution Testing  

Microsoft Academic Search

Scientists have known for years that deaeration of aqueous dissolution media can affect the dissolution rate of solid dosage forms. Several methods have been developed to accomplish deaeration, but the industry stan- dard has been the USP method, using heat, vacuum and filtering. Alternate methods of deaeration may be considered comparable to the USP method by passing the USP Apparatus

Thomas Curley; Richard Forsyth; Susan Sun; Kyle Fliszar; Mitch Colletto; Gregory P. Martin

41

Development and application of a biorelevant dissolution method using USP apparatus 4 in early phase formulation development.  

PubMed

Dissolution testing is frequently used to determine the rate and extent at which a drug is released from a dosage form, and it plays many important roles throughout drug product development. However, the traditional dissolution approach often emphasizes its application in quality control testing and usually strives to obtain 100% drug release. As a result, dissolution methods are not necessarily biorelevant and meaningful application of traditional dissolution methods in the early phases of drug product development can be very limited. This article will describe the development of a biorelevant in vitro dissolution method using USP apparatus 4, biorelevant media, and real-time online UV analysis. Several case studies in the areas of formulation selection, lot-to-lot variability, and food effect will be presented to demonstrate the application of this method in early phase formulation development. This biorelevant dissolution method using USP apparatus 4 provides a valuable tool to predict certain aspects of the in vivo drug release. It can be used to facilitate the formulation development/selection for pharmacokinetic (PK) and clinical studies. It may also potentially be used to minimize the number of PK studies, and to aid in the design of more efficient PK and clinical studies. PMID:20701327

Fang, Jiang B; Robertson, Vivian K; Rawat, Archana; Flick, Tawnya; Tang, Zhe J; Cauchon, Nina S; McElvain, James S

2010-09-02

42

Field test of a calcite dissolution rate law: Fort's Funnel Cave, Mammoth Cave National Park  

Microsoft Academic Search

The laboratory-derived calcite dissolution rate law of Plummer et al. (1978) is the most widely used and mechanistically detailed expression currently available for predicting dissolution rates as a function of water chemistry. Such rate expressions are of great use in understanding timescales associated with limestone karst development. Little work has gone into the field testing of the rate law under

J. S. Slunder; C. G. Groves

1994-01-01

43

Solution calorimetry as an alternative approach for dissolution testing of nanosuspensions.  

PubMed

The formulation of poorly soluble drugs as nanocrystals/nanosuspensions has rapidly evolved during the past decade into a mature drug-delivery strategy. The major characteristic of these systems is the high drug dissolution rate, enabling bioavailability enhancement after oral administration. It is therefore of great importance to have access to analytical methodology that is able to accurately monitor the extreme fast dissolution process of such formulations. The aim of the present study was to evaluate solution calorimetry as a novel approach to measure the dissolution rate of nanosuspensions by recording the temperature change in the dissolution vessel during the dissolution process of the nanocrystals. The applicability was tested on different nanosuspensions made up of three model drugs: naproxen, cinnarizine and an investigational API, i.e. compound A. The dissolution process of all nanosuspensions investigated was completed within less than 1 min. During this period, sufficient data points were collected to transform temperature offset data to cumulative heat of solution pointing to the potential of this technique. However, of significant concern is the fact that this technique measures the total heat produced or consumed by all processes that occur during the dissolution, e.g. the heat of mixing when the nanosuspension comes in contact with the dissolution medium. Erroneous conclusions will result if phenomena other than dissolution are not accounted for. PMID:20887787

Kayaert, P; Li, B; Jimidar, I; Rombaut, P; Ahssini, F; Van den Mooter, G

2010-09-29

44

Dissolution of prednisone tablets in the presence of an arch-shaped fiber optic probe in a USP dissolution testing apparatus 2.  

PubMed

During dissolution testing of solid dosage forms in the United States Pharmacopoeia (USP) Apparatus 2, samples are manually withdrawn from the medium in the vessel prior to the analysis. Probes permanently inserted in the medium can automate the sampling process but can also alter the system's hydrodynamics, possibly resulting in different dissolution-testing results. In this work, dissolution tests were conducted in a USP Apparatus 2 with and without an arch-shaped fiber optic probe using prednisone tablets fixed at nine different locations on the vessel bottom. The resulting dissolution profiles were compared using statistical tools. Dissolution rates obtained with the probe were typically higher than those obtained without the probe. The magnitude of the difference between dissolution profiles depended on the tablet location: Larger differences were observed with tablets located immediately downstream of the probe. The differences in dissolution profiles were generally small enough to satisfy the US Food and Drug Administration criteria (f1 and f2 values), although a paired t-test [P(t-test)] indicated that most of the profiles were statistically different [P(t-test) <0.05]. The hydrodynamic effects generated by the arch-shaped fiber optic probe resulted in detectable differences in the dissolution profiles, which, although limited, were clearly measurable and could introduce variations in test results. PMID:23861178

Zhang, Yiran; Bredael, Gerard; Armenante, Piero M

2013-07-16

45

Measurement of micro Bubbles generated by a pressurized dissolution method  

NASA Astrophysics Data System (ADS)

Diameters of micro-bubbles are apt to range from about one mm to several-hundred mm, and therefore, it is difficult to measure a correct diameter distribution using a single measurement method. In this study, diameters of bubbles generated by a pressurized dissolution method are measured by using phase Doppler anemometry (PDA) and an image processing method, which is based on the Sobel filter and Hough transform. The diameter distribution and the Sauter mean diameter of micro bubbles are evaluated based on the diameters measured by both methods. Experiments are conducted for several mass flow rates of dissolved gas and of air bubbles entrained in the upstream of the decompression nozzle to examine effects of the entrained bubbles on bubble diameter. As a result, the following conclusions are obtained: (1) Diameter distribution of micro bubbles can be accurately measured for a wide range of diameter by using PDA and the image processing method. (2) The mean diameter of micro-bubbles generated by gasification of dissolved gas is smaller than that generated by breakup of air bubbles entrained in the upstream of the decompression nozzle. (3) The mean bubble diameter increases with the entrainment of air bubbles in the upstream of the decompression nozzle at a constant mass flow rate of dissolved gas.

Hosokawa, S.; Tanaka, K.; Tomiyama, A.; Maeda, Y.; Yamaguchi, S.; Ito, Y.

2009-02-01

46

Development of Alkaline Oxidative Dissolution Methods for Chromium (III) Compounds Present in Hanford Site Tank Sludges  

SciTech Connect

The high-level radioactive waste sludge in the underground storage tanks at the Hanford Site contains various chromium solid phases. Dissolution and removal of chromium from tank waste sludges is desirable prior to high-level waste vitrification because increased volume is required to incorporate the residual chromium. Unfortunately, dissolution of chromium from the sludge to form Cr(OH){sub 4}{sup -} through treatment with heated NaOH solution (also used to dissolve aluminum phases and metathesize phosphates to sodium salts) generally has been unsuccessful in tests with both simulated and genuine Hanford waste sludges. Oxidative dissolution of the Cr(III) compounds to form soluble chromate has been proposed as an alternative chromium solid phase dissolution method and results of limited prior testing have been reported. The present systematic tests investigated oxygen gas, hydrogen peroxide, and sodium persulfate oxidants to dissolve Cr(III) under alkaline conditions to form soluble chromate. Permanganate and ozone also were considered for testing but were thought to be of secondary interest because of the insoluble residue (MnO{sub 2} from permanganate) and complex equipment (necessary to generate ozone) implicit with use of these reagents. The oxygen and hydrogen peroxide reagents leave no condensable residue and sodium persulfate only leaves soluble sodium sulfate. Crystalline Cr(OH){sub 3}, various hydrothermally aged amorphous Cr(III) oxide hydrates, mixed Fe(III)/Cr(III) oxide hydrates, and nickel and iron Cr(III) spinels, all of which have been identified or are likely constituents in Hanford tank wastes, were prepared and characterized for the dissolution tests. The effects of reagent and hydroxide concentrations, reaction temperature, and transition metal catalysts on reaction progress were investigated for each reagent as functions of reaction time. Reaction progress was measured by monitoring chromate concentration. Oxidation of chromium compounds by dissolved oxygen was found to increase linearly with oxygen partial pressure and NaOH concentration. The rate also increased with temperature at low activation energy, 26-36 kJ/mol, reflecting the opposing influences of decreasing oxygen volubility and increasing underlying chemical reaction rate. The reaction apparently proceeds by way of dissolved Cr(III) species, is catalyzed by Ni(II), and is slower for the hydrothermally aged materials. Dissolution rates ranged from about 7 x 10{sup -5} to 2.4 x 10{sup -4} moles Cr(III)/liter-hour in 80 C, 3-M NaOH with one atmosphere pure oxygen for the various Cr(III) compounds tested. These low dissolution rates commend the use of oxygen reagent to waste tank processing where extended residence times maybe practical. Oxidative dissolution of Cr(III) compounds by hydrogen peroxide was hampered in the presence of greater than 0.5 g Fe(III)/liter and other catalysts for H{sub 2}O{sub 2} decomposition and was less effective for materials that had undergone prolonged aging at high temperatures. Leaching was optimized at low excess NaOH and high temperatures (activation energy of {approx}82 kJ/mol). To prevent excessive loss of H{sub 2}O{sub 2} to catalytic decomposition, the peroxide reagent must be added slowly and with intense stirring. Treatment of waste solids with H{sub 2}O{sub 2} may only be attractive for freshly formed Cr(III) hydroxides [formed, for example, by alkaline metathesis of Cr(III)-bearing sludges] in the absence of decomposition catalysts such as Fe(III).

Delegard, Calvin H.; Krot, N N.; Shilov, V P.; Fedoseev, A M.; Budantseva, N A.; Nikonov, M V.; Yusov, A B.; Garnov, A Y.; Charushnikova, I A.; Perminov, V P.; Astafurova, L N.; Lapitskaya, T S.; Makarenkov, V I.

1999-07-02

47

Prediction of drug dissolution profiles from tablets using NIR diffuse reflectance spectroscopy: A rapid and nondestructive method  

Microsoft Academic Search

A comparison between dissolution profiles obtained by using a dissolution apparatus (conventional method) and the NIR diffuse reflectance spectra of a series of clonazepam-containing batches is reported. Ten different formulations with fixed amount of clonazepam and varying proportions of excipients were analyzed at seven dissolution times and three different media. The percentages of dissolution of each sample were correlated with

Matheus P. Freitas; Andréia Sabadin; Leandro M. Silva; Fábio M. Giannotti; Débora A. do Couto; Edivan Tonhi; Renato S. Medeiros; Gislaine L. Coco; Valter F. T. Russo; José A. Martins

2005-01-01

48

Oral Absorption of Poorly Water-Soluble Drugs: Computer Simulation of Fraction Absorbed in Humans from a Miniscale Dissolution Test  

Microsoft Academic Search

\\u000a Purpose  The purpose of this study was to develop a new system for computer simulation to predict fraction absorbed (Fa) of Biopharmaceutical Classification System (BCS) class II (low solubility–high permeability) drugs after oral administration\\u000a to humans, from a miniscale dissolution test.\\u000a \\u000a \\u000a \\u000a Methods  Human oral absorption of 12 lipophilic drugs was simulated theoretically by using the dissolution and permeation parameters\\u000a of the drugs.

Ryusuke Takano; Kiyohiko Sugano; Atsuko Higashida; Yoshiki Hayashi; Minoru Machida; Yoshinori Aso; Shinji Yamashita

2006-01-01

49

A review of methods used to compare dissolution profile data  

Microsoft Academic Search

In a number of recent guidance documents, the FDA has placed more emphasis on the meaningful comparison of dissolution profile data. For example, the FDA scale-up and post-approval changes–modified release (SUPAC–MR) guidance indicates that similar dissolution profiles for approved and modified formulations is acceptable justification for certain levels of change without prior FDA approval or the need to perform bioequivalence

Thomas O'Hara; Adrian Dunne; Jackie Butler; John Devane

1998-01-01

50

Improvement of the dissolution rate of nitrendipine using a new pulse combustion drying method.  

PubMed

Solid dispersions (SDs) of nitrendipine (NTD), a poorly water-soluble drug, were prepared with the Hypulcon pulse combustion dryer system, and the physicochemical properties of particles were investigated and compared with those of particles prepared with a spray dryer. The SD particles prepared with Hypulcon using Aerosil and Tween 80 as carriers showed improved properties over those prepared with a conventional spray dryer, such as smaller particle size, tighter particle size distribution, and no agglomeration. Powder X-ray diffraction and differential scanning calorimetry evaluation showed that the drug in the NTD-Aerosil SD prepared with 5% (v/v) Tween 80 solution was dispersed in an amorphous state. Fourier transformation IR spectroscopy indicated the presence of hydrogen bonds between NTD and Aerosil. Aerosil had greater ability to improve the dissolution of NTD than Sylysia and other polymers. The highest drug supersaturation concentration was maintained continuously during the dissolution test of the NTD-Aerosil SD prepared with 5% (v/v) Tween 80 solution using Hypulcon. The good hydrophilicity and dispersibility of Aerosil, solubilization of Tween 80, and actions of shock waves and ultrasonic waves might account for the amorphization of NTD and improved dissolution rate of SDs. Pulse combustion drying with low drying costs and high thermal efficiency is a promising method for the preparation of SD particles with improved properties without using organic solvent. PMID:17666831

Wang, Liang; Cui, Fu-De; Sunada, Hisakazu

2007-08-01

51

Evaluation of USP apparatus 3 for dissolution testing of immediate-release products  

Microsoft Academic Search

We sought to evaluate whether U.S. Pharmacopeia (USP) apparatus 3 can be used as an alternative to USP apparatus 2 for dissolution\\u000a testing of immediate-release (IR) dosage forms. Highly soluble drugs, metoprolol and ranitidine, and poorly soluble drugs,\\u000a acyclovir and furosemide, were chosen as model drugs. The dissolution profiles of both innovator and generic IR products were\\u000a determined using USP

Lawrence X. Yu; Jin T. Wang; Ajaz S. Hussain

2002-01-01

52

Dissolution of HTGR TRISO Beads by the Alkali Fluoride Fusion Method.  

National Technical Information Service (NTIS)

The alkali fluoride fusion method for the dissolution of HTGR TRISO fuel beads offers significant time advantage over other commonly used fusion procedures when applied to samples weighing less than three grams. The method is straightforward, utilizes sta...

S. E. Byster

1980-01-01

53

[Dissolution determination in the rotating flask model. Effect of rotation rate and fluid volume on the solubility determination of standard test tablets in the Resotest dissolution tester].  

PubMed

The influence of two important factors, the rotational speed and the fluid volume within the system, on the release characteristics of prednisone-test tablets in the rotating flask dissolution-tester (Resotest-apparatus after Koch) has been investigated. As a result, standard conditions for dissolution experiments with the rotating flask model, i.e. a mean rotation number of 30 r.p.m. and an actual fluid volume of 500 ml, are proposed. PMID:6611628

Koch, H P; Pfeifer, G

1983-05-01

54

Phase field and level set methods for modeling solute precipitation and/or dissolution  

SciTech Connect

The dynamics of solid-liquid interfaces controlled by solute precipitation and/or dissolution due to the chemical reaction at the interface were computed in two dimensions using a phase field models. Sharp-interface asymptotic analysis demonstrated that the phase field solutions should converge to the proper sharp-interface precipitation/dissolution limit. For the purpose of comparison, the numerical solution of the sharp-interface model for solute precipitation/dissolution was directly solved using a level set method. In general, the phase field results are found in good agreement with the level set results for all reaction rates and geometry configurations investigated. Present study supports the applications of both methods to more complicated and realistic reactive systems, including the nuclear waste release and mineral precipitation and dissolution

Zhijie Xu; Hai Huang; Paul Meakin

2012-01-01

55

Dissolution behavior of resist polymers studied using quartz crystal microbalance method  

NASA Astrophysics Data System (ADS)

The quartz crystal microbalance (QCM) method was used to obtain precise information about the dissolution behavior of resist polymers. The time evolutions of the resonance frequency and the impedance during the dissolution were measured using the QCM method. The data were simulated using the transmission line method on a four-layer model. Transmission line analysis showed Sauerbrey"s relation to be invalid during the formation and dissolution of the gel layer, although Sauerbrey"s relation was valid during the other development time with the constant thickness of the gel layer. The application of Sauerbrey"s relation in those transition areas brought out artificial changes of the dissolution or swelling rates. The rigidity of the gel layer was also analyzed from 102 to 107 Pa using the transmission line method. The resonance frequency changed drastically at less than 105 Pa during the formation and dissolution of the gel layer. The application of Sauerbrey"s relation in those transitional areas resulted in artificial changes of the dissolution rate from 5 nm/s to 92 nm/s and a shortening of the induction period from 5 s to 2.5 s. Transmittance analysis has shown the validity of quantitative analysis in QCM experiments.

Toriumi, Minoru

2005-05-01

56

Drug release phenomena within a hydrophobic starch acetate matrix: FTIR mapping of tablets after in vitro dissolution testing.  

PubMed

The aim of this study was to assess the utility of Fourier transform infrared mapping to study the drug release phenomena within a hydrophobic matrix tablet. Starch acetate with a degree of substitution (2.7) was used as a hydrophobic matrix former. Anhydrous caffeine and riboflavin sodium phosphate were used as water soluble model drugs. The USP (XXVIII) paddle-method was selected as an in vitro dissolution test. Mapping of the diluted tablets' cross-section was performed by attenuated total reflection mode. Fourier transform infrared mapping can distinguish drug particles from the bulk matrix and it can be considered as a valuable method for obtaining both quantitative and qualitative information on drug release processes. The physicochemical properties of the drug compound strongly contribute to its release behavior when the USP paddle in vitro dissolution test is used. Mapping of the riboflavin product revealed a more homogenous matrix distribution due to its smaller particle size. Consequently, its dissolution release profile was more uniform than caffeine which possessed a wider particle size distribution and lower solubility. Mapping showed that caffeine became localized in the lower part of the tablet unlike riboflavin. The hydrodynamic conditions during the in vitro release test might contribute to this differentiation. PMID:18085712

Pajander, Jari; Soikkeli, Anne-Marie; Korhonen, Ossi; Forbes, Robert T; Ketolainen, Jarkko

2008-08-01

57

Field test of a calcite dissolution rate law: Fort's Funnel Cave, Mammoth Cave National Park  

SciTech Connect

The laboratory-derived calcite dissolution rate law of Plummer et al. (1978) is the most widely used and mechanistically detailed expression currently available for predicting dissolution rates as a function of water chemistry. Such rate expressions are of great use in understanding timescales associated with limestone karst development. Little work has gone into the field testing of the rate law under natural conditions. This work measured dissolution rates by a crystal weight loss experiment in Buffalo Creek within Fort's funnel Cave, which lies within a pristine, forested catchment of Mammoth Cave National Park. Continuous water chemistry sampling over the same period allowed a time-integrated prediction of the dissolution based on the Plummer et al. (1978) expression. Results indicate that the rate law overpredicted dissolution by a factor of about ten. This concurs with earlier laboratory work suggesting that the law tends to overpredict rates in solutions close to equilibrium with respect to calcite, as were the waters within this part of the groundwater flow system.

Slunder, J.S. (EMPE Inc., Nashville, TN (United States)); Groves, C.G. (Western Kentucky Univ., Bowling Green, KY (United States). Center for Cave and Karst Studies)

1994-03-01

58

Validation Testing of the Nitric Acid Dissolution Step Within the K Basin Sludge Pretreatment Process  

SciTech Connect

The work described in this report involved comprehensive bench-scale testing of nitric acid (HNO{sub 3}) dissolution of actual sludge materials from the Hanford K East (KE) Basin to confirm the baseline chemical pretreatment process. In addition, process monitoring and material balance information was collected to support the development and refinement of process flow diagrams. The testing was performed by Pacific Northwest National Laboratory (PNNL)for the US Department of Energy's Office of Spent Fuel Stabilization (EM-67) and Numatec Hanford Corporation (NHC) to assist in the development of the K Basin Sludge Pretreatment Process. The baseline chemical pretreatment process for K Basin sludge is nitric acid dissolution of all particulate material passing a 1/4-in. screen. The acid-insoluble fraction (residual solids) will be stabilized (possibly by chemical leaching/rinsing and grouting), packaged, and transferred to the Hanford Environmental Restoration Disposal Facility (ERDF). The liquid fraction is to be diluted with depleted uranium for uranium criticality safety and iron nitrate for plutonium criticality safety, and neutralized with sodium hydroxide. The liquid fraction and associated precipitates are to be stored in the Hanford Tank Waste Remediation Systems (TWRS) pending vitrification. It is expected that most of the polychlorinated biphenyls (PCBs), associated with some K Basin sludges, will remain with the residual solids for ultimate disposal to ERDF. Filtration and precipitation during the neutralization step will further remove trace quantities of PCBs within the liquid fraction. The purpose of the work discussed in this report was to examine the dissolution behavior of actual KE Basin sludge materials at baseline flowsheet conditions and validate the.dissolution process step through bench-scale testing. The progress of the dissolution was evaluated by measuring the solution electrical conductivity and concentrations of key species in the dissolver solutions as a function of reaction (dissolution) time, by analyzing offgas generation rate and composition, and by analyzing intermittent and final acid-insoluble solids at the end of the dissolution. The testing was conducted in a system designed to assess parameters that can influence sludge dissolution and provide information that can be used to determine operating conditions for the actual system.

AJ Schmidt; CH Delegard; KL Silvers; PR Bredt; CD Carlson; EW Hoppe; JC Hayes; DE Rinehart; SR Gano; BM Thornton

1999-03-24

59

A description of forsterite dissolution using ab initio methods  

SciTech Connect

Molecular clusters representative of protonated, neutral, and deprotonated sites on a forsterite (Mg2SiO4) surface were employed to facilitate examination of Mg Obr bond-breaking via DFT calculations with the B3LYP/6-31+G(d,p) methodology. Hydrolysis reactions of the molecular clusters with a H2O molecule yielded barrier heights of 21, 54, and 39 kJ/mol for protonated, neutral, and deprotonated sites in the gas-phase, respectively, and the rate constants calculated using these barrier heights were 5.7x108, 2.7x104, and 2.2x106 s-1, respectively. Aqueous-phase calculations on the gas-phase structures were also performed, and the barrier heights were 33, 40, and 21 kJ/mol for the protonated, neutral, and deprotonated models. Rate constants were 4.3x106, 6.1x105, and 6.0x108 s-1. For models energy-minimized in the aqueous-phase the barrier heights were 42, 44, and 40 kJ/mol, and the rate constants were 1.4x107, 3.0x104, and 9.9x105 s-1, respectively. These differences highlight the importance of modeling structures with inclusion of solvent effects. Rates of Mg2+ release from the forsterite surface were predicted using these rate constants and models of the reactive site density and the H+ or OH surface speciation. These calculations are consistent with a more rapid rate of Mg2+ release under acidic conditions even though the activation energy barriers are equivalent within computational uncertainty. A comparison of these results to previous data shows that the predicted rates are much faster than experimentally measured dissolution rates, and this suggests that the Mg Obr bond break is a rapid process which is a component of Mg2+ release from the surface consistent with previous experimental observation of preferential Mg2+ leaching from forsterite. A dissolution mechanism involving polymerization and hydrolysis of Si Obr Si linkages is discussed that is consistent with the discrepancy between Mg2+ release rates and dissolution rates of forsterite.

Morrow, Christin [Pennsylvania State University; Kubicki, James D. [Pennsylvania State University; Mueller, Karl [Pennsylvania State University; Cole, David R [ORNL

2009-01-01

60

Effect of different preparation methods on the dissolution behaviour of amorphous indomethacin.  

PubMed

The aim of this study was to investigate whether amorphous indomethacin samples prepared using different preparative techniques and processing parameters exhibit different structural and thermodynamic characteristics and whether these differences can be correlated to their dissolution behaviour. Samples were prepared either by cooling the drug melt at different cooling rates or by cryo-milling the drug for different milling times. The resulting amorphous materials were characterised using X-ray diffraction, Raman spectroscopy and polarising light microscopy. All samples were entirely X-ray amorphous, except for the sample cryo-milled for 15 min, which exhibited residual crystallinity. The shape of the halos in the diffractograms, however, varied depending on the preparation method and processing parameters, suggesting structural variations in the near order of the molecules between the prepared amorphous forms. This finding was supported by principal component analysis of the Raman spectra, as the samples clustered in the scores plot according to processing parameters for both of the preparative methods used. When investigating the dissolution behaviour, the samples cooled at different cooling rates showed no significant differences in their dissolution profiles and dissolution rates (?0.55 ?g/ml/cm(2)). In contrast, for cryo-milled samples, dissolution rate depended on the milling time, with samples milled for 120, 180 and 240 min, showing significantly increased dissolution rates of 0.28, 0.48 and 0.59 ?g/ml/cm(2), respectively, when compared to crystalline indomethacin (?0.06 and 0.05 ?g/ml/cm(2) for ? and ?-indomethacin, respectively). The milling processes appear to continue to affect the degree of disorder in the solid material, enhancing its dissolution rate, although all samples milled for > 30 min were X-ray amorphous. Thus, choosing the right preparation technique and parameters for preparing amorphous solids is critical for producing materials with enhanced dissolution profiles. PMID:22019529

Karmwar, Pranav; Graeser, Kirsten; Gordon, Keith C; Strachan, Clare J; Rades, Thomas

2011-10-14

61

Guidance on Levetiracetam Please note that a Dissolution ...  

Center for Drug Evaluation (CDER)

Text Version... Dissolution test method and sampling times: Please note that a Dissolution Methods Database is available to the public at the OGD website at http ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

62

Cause of high variability in drug dissolution testing and its impact on setting tolerances.  

PubMed

Considering a variable mixing/stirring and flow pattern in a drug dissolution vessel as a likely source of high variability in results, experiments were conducted using USP paddle apparatus by placing (aligned to the walls) a metal strip (1.7 mm thickx6.4 mm wide) in a dissolution vessel. The metal strip forces the undisintegrated tablet to settle about 3 mm away from the centre, facilitates spread of disintegrated material and diminishes the cone formation at the bottom of the vessel. To assess the impact of this altered environment in the vessel, but still maintaining the vessel dimensions within required specifications, drug release characteristics were evaluated for products having different formulation/manufacturing attributes. Tests were conducted with calibrator tablets (USP prednisone and salicylic acid tablets and FDA proposed NCDA No. 2 prednisone tablets) and two commercially available products (250 mg amoxicillin capsules and 5 mg glibenclamide tablets). Except for the glibenclamide tablet product, all products gave significantly (P<0.01) higher dissolution results with vessels containing metal strip than without. The extent of increased dissolution with the metal strip varied from product to product i.e. USP prednisone tablet was the smallest (14.4%) and NCDA No. 2 was the largest (88.4%). Based on the results obtained from this study, it is concluded that employing the current apparatuses, in many cases products will provide lower than anticipated results which may not be reflective of the product drug release characteristics. Test-to-test variability, within or between laboratories, can also be very high depending on the settling position of the product once dropped in the vessel and/or due to slight aberration in the walls of the vessel by altering the extent of spread of disintegrated material at the bottom of the vessel. Thus, dissolution testing will require wider tolerances to be useful for comparison of batch-to-batch or interlaboratory results. PMID:11113646

Qureshi, S A; Shabnam, J

2001-01-01

63

Dissolution testing of a metallic waste form in chloride brine  

SciTech Connect

This paper is intended for publication in the peer-reviewed proceedings from the Scientific Basis for Nuclear Waste Management (at the Fall 2006 meeting of the Materials Research Society). The same material was presented in a 15-minute talk. Argonne National Laboratory has developed an electrometallurgical process for conditioning spent sodium-bonded metallic reactor fuel from the Experimental Breeder Reactor II (EBR-II). One waste stream from this process consists of a metal waste form (MWF) whose baseline composition is stainless steel alloyed with 15 wt% Zr (SS-15Zr) and whose microstructure is a eutectic intergrowth of iron solid solutions and Fe-Zr-Cr-Ni intermetallics. This paper reports scanning electron microscope (SEM) observations of corrosion products formed during static immersion tests in which coupons of surrogate MWF containing 10 wt% U (SS-15Zr-10U) were immersed in solutions with nominal pH values of 3 and 4 and 1000 ppm added chloride for 70 days at 50 °C. Although the majority of the surface areas of the coupons appear unchanged, linear areas with localized corrosion products apparently consisting of porous materials overlying corrosion-product-filled channels formed on both coupons, cross-cutting phase boundaries in the original eutectic microstructures. Many of the linear areas intersected the sample edge at notches present before the tests or followed linear flaws visible in pre-test images. Compositions of corrosion products differed significantly from the bulk composition, and the maximum observed concentration of U in corrosion products (~25 at%) slightly exceeded the highest reported values in actinide-bearing phases in uncorroded surrogate MWF samples with comparable concentrations of U (~17-19 at%).

Dawn E Janney

2006-11-01

64

Quality evaluation of generic drugs by dissolution test: changing the USP dissolution medium to distinguish between active and non-active mebendazole polymorphs  

Microsoft Academic Search

Mebendazole is practically insoluble in water and studies of its polymorphism has led to the identification and characterization of three polymorphic forms (A, B, C) displaying solubility and therapeutic differences that show that polymorph C is therapeutically favored. The objective of this study was to adjust the USP dissolution test for mebendazole so that it was able to distinguish between

Erna Swanepoel; Wilna Liebenberg; Melgardt M. de Villiers

2003-01-01

65

Prediction of food effects on the absorption of celecoxib based on biorelevant dissolution testing coupled with physiologically based pharmacokinetic modeling  

Microsoft Academic Search

Since the rate-determining step to the intestinal absorption of poorly soluble drugs is the dissolution in the gastrointestinal (GI) tract, postprandial changes in GI physiology, in addition to any specific interactions between drug and food, are expected to affect the pharmacokinetics and bioavailability of such drugs. In this study, in vitro dissolution testing using biorelevant media coupled with in silico

Yasushi Shono; Ekarat Jantratid; Niels Janssen; Filippos Kesisoglou; Yun Mao; Maria Vertzoni; Christos Reppas; Jennifer B. Dressman

2009-01-01

66

Phase field and level set methods for modeling solute precipitation and/or dissolution  

SciTech Connect

The dynamics of solid-liquid interfaces controlled by solute precipitation and/or dissolution due to the chemical reaction at the interface were computed in two dimensions using a phase field models. Sharp-interface asymptotic analysis demonstrated that the phase field solutions should converge to the proper sharp-interface precipitation/dissolution limit. For the purpose of comparison, the numerical solution of the sharp-interface model for solute precipitation/dissolution was directly solved using a level set method. In general, the phase field results are found in good agreement with the level set results for all reaction rates and geometry configurations. Present study supports the applications of both methods to more complicated and realistic reactive systems.

Xu, Zhijie; Huang, Hai; Li, Xiaoyi; Meakin, Paul

2012-01-02

67

Method for Improving Dissolution Efficiency in Gas-Absorption and Liquid Extraction Processes.  

National Technical Information Service (NTIS)

A method is described for improving dissolution efficiency in processes in which a feed fluid is introduced to a zone where it is contacted with a liquid solvent for preferentially removing a component of the feed and where part of the solvent so contacte...

B. E. Kanak M. J. Stephenson

1980-01-01

68

Method for improving dissolution efficiency in gas-absorption and liquid extraction processes  

Microsoft Academic Search

This invention is a method for improving dissolution efficiency in processes in which a feed fluid is introduced to a zone where it is contacted with a liquid solvent for preferentially removing a component of the feed and where part of the solvent so contacted undergoes transfer into the feed fluid to saturate the same. It has been found that

B. E. Kanak; M. J. Stephenson

1981-01-01

69

Method for improving dissolution efficiency in gas-absorption and liquid extraction processes. [Patent application  

Microsoft Academic Search

A method is described for improving dissolution efficiency in processes in which a feed fluid is introduced to a zone where it is contacted with a liquid solvent for preferentially removing a component of the feed and where part of the solvent so contacted undergoes transfer into the feed fluid to saturate the same. It has been found that such

B. E. Kanak; M. J. Stephenson

1980-01-01

70

A comparison of mathematical methods for the determination of in vitro dissolution constants for glass fibers.  

PubMed

Biopersistence plays a significant role in determining the potential bioactivity of respirable fibers. In vivo biopersistence in the lung is frequently assessed by in vitro fiber dissolution studies using simulated biological solutions and flow-through techniques. The dissolution rate (k) of a fiber is typically determined by elemental analysis of the flow-through solution to measure the mass of material leached from the fibers over a given time. Various methods may be used to estimate the value of k from these results. The present study compared the in vitro dissolution characteristics of seven experimental glass fiber compositions to those obtained for four recognized fiber compositions (MMVF 10-glass fiber; MMVF 11-glass fiber; MMVF 21-rockwool fiber; crocidolite fiber). Fiber dissolution was examined over a 17-wk period using a flow-through system designed to simulate the conditions encountered by fibers in the extracellular environment of the lung. Mass loss and changes in fiber diameter were determined over time and were then used to calculate k using five different methods. Although the selected methodologies did not produce identical estimations of k for each fiber, the resulting ranking of fiber solubility for each method was consistent. The seven experimental glass fibers were found to have k values intermediate between those of MMVF 11 and MMVF 21. PMID:12528045

Foy, Jeffrey W-D; Collier, Clare; Swauger, James E

2003-02-01

71

USP Responses to Comments on Stimuli Article, ''Proposed Change to Acceptance Criteria for Dissolution Performance Verification Testing  

Microsoft Academic Search

* Todd L. Cecil, William Brown, Darrell R. Abernethy, William F. Koch, Roger L. Williams, USP ABSTRACT Pharmacopeial Forum 33(3) (May-June 2007) included a Stimuli article titled ''Proposed Change to Acceptance Criteria for Dissolution Performance Verification Testing.'' This Stimuli article proposed changing the form of the acceptance criteria for the Performance Verification Test (PVT) associated with USP Dissolution h711i to

Walter W. Hauck; Todd L. Cecil; William Brown; Darrell R. Abernethy; William F. Koch; Roger L. Williams

72

Method for dissolution and stabilization of silica-rich fibers  

DOEpatents

This invention is comprised of a method for dissolving silica-rich fibers such as borosilicate fibers, fiberglass and asbestos to stabilize them for disposal. The method comprises (1) immersing the fibers in hot, five-weight-percent sodium hydroxide solution until the concentration of dissolved silica reaches equilibrium and a only a residue is left (about 48 hours), then immersing the residue in hot, five-weight-percent nitric acid until the residue dissolves (about 96 hours). After adjusting the pH of the dissolved fibers to be caustic, the solution can then be added to a waste vitrification stream for safe disposal. The method is useful in disposing contaminated HEME and HEPA filters.

Jantzen, C.M.

1992-12-31

73

A method for testing denture adhesives.  

PubMed

An in vitro test method is described simulating the in vivo fate of a denture adhesive, i.e., destruction of the adhesive, dilution, and dissolution, by measuring the bond strength for the adhesive placed between acrylic resin plates. Between each measurement, the adhesive was exposed to isotonic saline. The bond strength for two ointment denture adhesives, Super Corega and Fixodent, was measured and the results were compared with those obtained for one of them in a previous in vivo test. The test method described for denture adhesives seems useful to depict the fate of a denture adhesive in clinical use. PMID:1791561

Fløystrand, F; Koppang, R; Williams, V D; Orstavik, J

1991-10-01

74

Assessment of methods for studying the dissolution of phosphate fertilizers of differing solubility in soil  

Microsoft Academic Search

An isotopic exchange method, based on tracer kinetic theory, was used to study the dissolution (Fin) and retention (Fout) of Phosphate (P) fertilizers in the soil. This method involves labelling of the soil with carrier-free32P-phosphate ions, and monitoring changes with time of specific activity of isotopically exchangeable phosphate in the soil as extracted by plants, and of the amounts of

H. J. Di; R. Harrison; A. S. Campbell

1994-01-01

75

Improved dissolution and chemical separation methods for Lu-Hf garnet chronometry  

NASA Astrophysics Data System (ADS)

Garnet-based Lu-Hf geochronology using conventional (HF-HNO3) dissolution methods may be compromised by full or partial digestion of Hf-rich zircon inclusions. This study integrates two complimentary methods to substantially reduce zircon digestion while assuring complete digestion of garnet and sample-spike equilibration. Handpicked garnet fractions are heat treated to >1000°C in an evacuated silica glass ampoule to anneal zircon inclusions and then dissolved with 12 M HCl at 210°C and cold 28 M HF. Analyses of heat-treated garnet (and their high-temperature breakdown products orthopyroxene-spinel-quartz) from Gore Mountain, New York, demonstrate the method is capable of complete dissolution of garnet and routinely achieving sample-spike equilibration. Independent analyses of annealed and unannealed zircons dissolved by HCl - cold HF demonstrate the benefit of heat treatment prior to dissolution. Analyses of zircon-rich garnets from peletic paragneisses of Labrador, Canada, show the potential of this method by returning Lu-Hf ratios commensurate with the degree of heat treatment. Finally, a complementary chemical separation method for Lu and Hf is presented that supports analysis of garnet by MC-ICP-MS.

Connelly, J. N.

2006-04-01

76

Leaching tests on different mortars using accelerated electrochemical method  

Microsoft Academic Search

In designing radioactive waste repositories, it is necessary to predetermine the degree of concrete performance change due to leaching degradation. Leaching tests were carried out on different mortars using an electrochemical method. With this method, a potential gradient is applied across the specimen, which accelerates the dissolution of cement hydrate from mortar in contact with water. Tests were carried out

Hiroshi Saito; Akira Deguchi

2000-01-01

77

FIP\\/AAPS Joint Workshop Report: Dissolution\\/ In Vitro Release Testing of Novel\\/Special Dosage Forms  

Microsoft Academic Search

In 2003, the FIP Dissolution Working group published a position paper on dissolution\\/drug release testing for special\\/novel\\u000a dosage forms that represented the scientific opinions of many experts in the field at that time (1). The position paper has supported activities, programs, and decisions in the scientific, technical, and regulatory community.\\u000a Due to the rapid evolution of new practices and techniques

Cynthia K. Brown; Horst Dieter Friedel; Amy R. Barker; Lucinda F. Buhse; Susanne Keitel; Todd L. Cecil; Johannes Kraemer; J. Michael Morris; Christos Reppas; Mary P. Stickelmeyer; Chikako Yomota; Vinod P. Shah

2011-01-01

78

Dissolution of phosphate rocks in soils. 1. Evaluation of extraction methods for the measurement of phosphate rock dissolution  

Microsoft Academic Search

The dissolution of phosphate rock (PR) in soil was determined by measuring the amount of either the dissolved inorganic phosphate (Pi) and Ca or the residual P and Ca remaining as undissolved PR in the soil. The dissolved Pi was extracted by either 0.5M NaOH or 0.5M NaHCO3 and the dissolved Ca was extracted using either 0.5M BaCl2\\/triethanolamine (TEA) or

N. S Bolan; M. J. Hedley

1989-01-01

79

Selective chemical dissolution of sulfides: An evaluation of six methods applicable to assaying sulfide-bound nickel  

USGS Publications Warehouse

Six analytical techniques for the selective chemical dissolution of sulfides are compared with the purpose of defining the best method for accurately determining the concentration of sulfide-bound nickel. Synthesized sulfide phases of known elemental content, mixed with well-analyzed silicates, were used to determine the relative and absolute efficiency, based on Ni and Mg recovery, of the techniques. Tested leach-methods purported to dissolve sulfide from silicate phases include: brominated water, brominated water-carbon tetrachloride, nitric-hydrochloric acid, hydrogen peroxide-ammonium citrate, bromine-methanol and hydrogen peroxide-ascorbic acid. Only the hydrogen peroxide-ammonium citrate method did not prove adequate in dissolving the sulfide phases. The remaining five methods dissolved the sulfide phases, but the indicated amount of attack on the silicate portion ranged from 3% to 100%. The bromine-methanol method is recommended for assaying sulfide-Ni deposits when Ni is also present in silicate phases. ?? 1986.

Klock, P. R.; Czamanske, G. K.; Foose, M.; Pesek, J.

1986-01-01

80

Results from NNWSI [Nevada Nuclear Waste Storage Investigations] Series 2 bare fuel dissolution tests  

SciTech Connect

The dissolution and radionuclide release behavior of spent fuel in groundwater is being studied by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Two bare spent fuel specimens plus the empty cladding hulls were tested in NNWSI J-13 well water in unsealed fused silica vessels under ambient hot cell air conditions (25{degree}C) in the currently reported tests. One of the specimens was prepared from a rod irradiated in the H. B. Robinson Unit 2 reactor and the other from a rod irradiated in the Turkey Point Unit 3 reactor. Results indicate that most radionuclides of interest fall into three groups for release modeling. The first group principally includes the actinides (U, Np, Pu, Am, and Cm), all of which reached solubility-limited concentrations that were orders of magnitude below those necessary to meet the NRC 10 CFR 60.113 release limits for any realistic water flux predicted for the Yucca Mountain repository site. The second group is nuclides of soluble elements such as Cs, Tc, and I, for which release rates do not appear to be solubility-limited and may depend on the dissolution rate of fuel. In later test cycles, {sup 137}Cs, {sup 90}Sr, {sup 99}Tc, and {sup 129}I were continuously released at rates between about 5 {times} 10{sup {minus}5} and 1 {times} 10{sup {minus}4} of inventory per year. The third group is radionuclides that may be transported in the vapor phase, of which {sup 14}C is of primary concern. Detailed test results are presented and discussed. 17 refs., 15 figs., 21 tabs.

Wilson, C.N.

1990-09-01

81

Corrosion tests to determine temperature and pH dependencies of the dissolution rates of sodalite, binder glass, and ceramic waste form.  

SciTech Connect

A glass bonded-sodalite ceramic waste form (CWF) has been developed to immobilize salt wastes from electrometallurgical treatment of sodium-bonded spent nuclear fuel. The CWF is a composite of salt-loaded sodalite and a binder glass formed at high temperature (850-950 C) by hot isostatic pressing (HIP) or pressureless-consolidation (PC) processes. A waste form degradation and radionuclide release model has been developed to support qualification of the CWF for disposal in the proposed repository at Yucca Mountain. Six series of tests were conducted in conjunction with the development of that model. (1) Static tests were conducted to measure the dissolution rate of sodalite, HIP binder glass, and HIP CWF at 40, 70, and 90 C in pH range 4.8-9.8 buffer solution. The parameter values in the degradation model were calculated from the dissolution rates measured by the static tests. (2) Static tests were conducted at 70 C in noncomplexing tertiary amine pH buffers to confirm that the dissolution rate measured with traditional buffers was not affected by the complexation of metal ions. The results showed that the difference between dissolution rate determined with noncomplexing buffer and that determined with traditional buffers was negligible. (3) Static tests were conducted in five buffer solutions in the pH range 4.8-9.8 at 20 C with HIP sodalite, HIP glass, and HIP CWF. The results showed that the model adequately predicts the dissolution rate of these materials at 20 C. (4) Static tests at 20 and 70 C with CWF made by the PC process indicated that the model parameters extracted from the results of tests with HIP CWF could be applied to PC CWF. (5) The dissolution rates of a modified glass made with a composition corresponding to 80 wt% glass and 20 wt% sodalite were measured at 70 C to evaluate the sensitivity of the rate to the composition of binder glass in the CWF. The dissolution rates of the modified binder glass were indistinguishable from the rates of the binder glass. (6) The dissolution rate of a simple five-component glass (CSG) was measured at 70 C using static tests and single-pass flow-through (SPFT) tests. Rates were similar for the two methods; however, the measured rates are about 10X higher than the rates measured previously at Lawrence Livermore National Laboratory (LLNL) for a glass having the same composition using an SPFT test method. Differences are attributed to effects of the solution flow rate on the glass dissolution rate and how the specific surface area of crushed glass is estimated. This comparison indicates the need to standardize the SPFT test procedure.

Jeong, S.-Y.; Fanning, T. H.; Morss, L. R.; Ebert, W. L.

2003-02-12

82

[The investigation of nickel dissolution from nitinol under different extraction conditions in biological tests].  

PubMed

The dissolution of nickel from nitinol alloy under different extraction conditions was investigated when biological tests of nitinol medical devices were carried out. It discussed the equivalence of these extraction conditions and found the best extraction conditions. In the experiment, two brands of nitinol were chosen and extracted under different extraction conditions according to GB/T 16886-12. Plasma emission spectrometer was used to analyse the concentration of nickel in extract liquid. The results show that there is no equivalence among these extraction conditions for nitinol materials. And it is suggested that (37 +/- 1) degree C, (72 +/- 2) h could be used as normal extraction condition and (70 +/- 2) degrees C, (24 +/- 2) h as accelerated extraction condition. PMID:23777071

Wen, Xiantao; He, Xueying; Li, Jian; Tang, Juli; Huang, Yongfu

2013-03-01

83

Critical dissolution tests of oral systems based on statistically designed experiments. II. In vitro optimization of screened variables on ER-coated spheres for the establishment of an in vitro/in vivo correlation.  

PubMed

The study was designed to optimize the effects of the screened in vitro dissolution variables agitation, temperature, osmolality, and polarity on the release of the neuroleptic compound remoxipride from extended release coated spheres. The variables were varied independently by means of a fractional factorial design. The in vitro tests were performed with the Basket method (USP). The polarity and the osmolality of the medium had significant effects on the dissolution rate of remoxipride. A statistical model was calculated based on the obtained dissolution in vitro. The model was then used to predict the in vitro conditions that most closely correlated with the dissolution rate of remoxipride in vivo, after administration of the formulation to 16 volunteers. The predicted in vitro conditions were experimentally verified, and an excellent association with the in vivo behavior of the formulation was found. Validation of the optimal in vitro conditions was performed on another batch of the formulation. The dissolution profile obtained showed a significant association with the corresponding dissolution profile in vivo. The use of statistically designed experiments in the development of critical dissolution tests for the establishment of in vitro/in vivo correlations seems to be a useful working approach, and supports further application to other oral solid systems. PMID:9876576

Abuzarur-Aloul, R; Gjellan, K; Sjölund, M; Graffner, C

1998-03-01

84

Salt dissolution in oil and gas test holes in central Kansas. Part II. Salt dissolution in oil and gas test holes in the Gorham Oilfield, Russell County, central Kansas  

Microsoft Academic Search

Within the Gorham Oilfield, there are two areas of surface subsidence caused by salt dissolution in three abandoned oil wells. Since these subsidence areas seriously affect Interstate Highway 70, they were carefully surveyed and studied. The Crawford Sink with over 20 feet of surface subsidence was investigated by the State Highway Commission by drilling a test hole between the abandoned

1975-01-01

85

Preparation of stable nitrendipine nanosuspensions using the precipitation-ultrasonication method for enhancement of dissolution and oral bioavailability.  

PubMed

The aim of this study was to prepare and characterize nitrendipine nanosuspensions to enhance the dissolution rate and oral bioavailability of this drug. Nanosuspensions were prepared by the precipitation-ultrasonication method. The effects of five important process parameters, i.e. the concentration of PVA in the anti-solvent, the concentration of nitrendipine in the organic phase, the precipitation temperature, the power input and the time length of ultrasonication on the particle size of nanosuspensions were investigated systematically, and the optimal values were 0.15%, 30 mg/ml, below 3 degrees C, 400 W and 15 min, respectively. The particle size and zeta potential of nanocrystals were 209 nm (+/- 9 nm) and -13.9 mV (+/-1.9 mV), respectively. The morphology of nanocrystals was found to be flaky in shape by scanning electron microscopy (SEM) observation. The X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) analysis indicated that there was no substantial crystalline change in the nanocrystals compared with raw crystals. The in vitro dissolution rate of nitrendipine was significantly increased by reducing the particle size. The in vivo test demonstrated that the C(max) and AUC(0-->12) values of nanosuspension in rats were approximately 6.1-fold and 5.0-fold greater than that of commercial tablets, respectively. PMID:20417274

Xia, Dengning; Quan, Peng; Piao, Hongze; Piao, Hongyu; Sun, Shaoping; Yin, Yongmei; Cui, Fude

2010-04-22

86

Dissolution Kinetics of Titanate-Based Ceramic Waste Forms: Results from Single-Pass Flow Tests on Radiation Damaged Specimens  

SciTech Connect

This report is a summary report in which the data from the single-pass flow-through test on resintered 238Pu-bearing ceramics are reported. These results show that radiation damage has litte effect on the dissolution kinetics of candidate titanate ceramics for plutonium immobilization.

Icenhower, Jonathan P.; Strachan, Denis M.; Lindberg, Michael J.; Rodriguez, Elsa A.; Steele, Jackie L.

2003-05-01

87

Irregular absorption profiles observed from diclofenac extended release tablets can be predicted using a dissolution test apparatus that mimics in vivo physical stresses  

Microsoft Academic Search

The prediction of the in vivo drug release characteristics of modified release oral dosage forms by in vitro dissolution tests is a prerequisite for successful product development. A novel dissolution test apparatus that mimics the physical conditions experienced by an oral formulation during gastrointestinal transit was developed. This included the simulation of pressure forces exerted by gut wall motility, shear

Grzegorz Garbacz; Ralph-Steven Wedemeyer; Stefan Nagel; Thomas Giessmann; Hubert Mönnikes; Clive G. Wilson; Werner Siegmund; Werner Weitschies

2008-01-01

88

Development and validation of a HPLC method for dissolution and stability assay of liquid-filled cyclosporine capsule drug products.  

PubMed

To assay the dissolution samples of a drug product from several sources, a simple but broadly applicable analytical method is always desired. For the liquid-filled cyclosporine capsules, while analyzing the dissolution samples, the current compendial and literature HPLC methods have been found to be inadequate to provide satisfactory separation of the drug and the excipient peaks. Accordingly, a suitable isocratic reverse-phase HPLC method was developed for the analysis of dissolution samples of liquid-filled cyclosporine capsules. The method successfully separated the cyclosporine peak from the interfering chromatographic peaks of the excipients. The method was validated according to the ICH and FDA guidelines. Specificity, selectivity, linearity, accuracy, precision, and robustness were established over 3 days as part of method validation. Additionally, the degradation kinetics of cyclosporine in dissolution media was determined. Cyclosporine degradation followed a zero-order kinetics in the dissolution media with the respective rate constants of -3.5, -1.5, and -0.3%/h at 37°C, 25°C, and 10°C. PMID:23761263

Xu, Xiaoming; Gupta, Abhay; Faustino, Patrick; Sathe, Pradeep M; Sayeed, Vilayat A; Khan, Mansoor A

2013-06-13

89

Powdered epoxy resin test methods  

Microsoft Academic Search

The author describes several test methods which may be used to evaluate powdered epoxy resins for their potential use as integral insulation on fractional horsepower motor iron. These are the edge coverage test method, the hot plate gel time test method, the glass pellet flow test method, and the steel panel impact test method. These test methods may be of

N. Hanssen

1991-01-01

90

Theophylline granule formulation prepared by the wet granulation method: comparison of in vitro dissolution profiles and estimation of in vivo plasma concentrations  

Microsoft Academic Search

Summary  The primary and secondary objectives of this study were to develop and evaluate the predictability of in vitro-in vivo correlation\\u000a models for theophylline sustained release (SR) granules. Theophylline SR granules meeting the USP Drug Release Test criteria\\u000a were prepared using ethyl cellulose (EC) and\\/or stearyl alcohol (SA) and the wet granulation method. In vitro dissolution\\u000a studies of granule formulation were

E. KARASULUI; ?. Apaydin; ? I. Ince; I. Tu?lular

2006-01-01

91

Dissolution studies of poorly soluble drug nanosuspensions in non-sink conditions.  

PubMed

Sink conditions used in dissolution tests lead to rapid dissolution rates for nanosuspensions, causing difficulties in discriminating dissolution profiles between different formulations. Here, non-sink conditions were studied for the dissolution testing of poorly water-soluble drug nanosuspensions. A mathematical model for polydispersed particles was established to clarify dissolution mechanisms. The dissolution of nanosuspensions with either a monomodal or bimodal size distribution was simulated. In the experimental part, three different particle sizes of indomethacin nanosuspensions were prepared by the wet milling technique. The effects of the dissolution medium pH and agitation speed on dissolution rate were investigated. The dissolution profiles in sink and non-sink conditions were obtained by changing the ratio of sample amount to the saturation solubility. The results of the simulations and experiments indicated that when the sample amount was increased to the saturation solubility of drug, the slowest dissolution rate and the best discriminating dissolution profiles were obtained. Using sink conditions or too high amount of the sample will increase the dissolution rate and weaken the discrimination between dissolution profiles. Furthermore, the low solubility by choosing a proper pH of the dissolution medium was helpful in getting discriminating dissolution profiles, whereas the agitation speed appeared to have little influence on the dissolution profiles. This discriminatory method is simple to perform and can be potentially used in any nanoproduct development and quality control studies. PMID:23615772

Liu, Peng; De Wulf, Odile; Laru, Johanna; Heikkilä, Teemu; van Veen, Bert; Kiesvaara, Juha; Hirvonen, Jouni; Peltonen, Leena; Laaksonen, Timo

2013-04-25

92

Method of inhibiting gravel pack and formation sandstone dissolution during steam injection  

SciTech Connect

A method is claimed of inhibiting dissolution of the gravel pack and/or erosion of the formation standstone in a well bore subject to water or steam injection. The method includes the addition of a material to the surface of the gravel or formation which is capable of adhering to such surfaces and forming a tenacious water-repellent film. The film is monomolecular and hydrophobic. The active ingredient in the chemical treatment is commercial soybean lecithin. The material is added to the surfaces by injecting a liquid solution of the chemical down the annulus of the well during steaming and/or physically precoating the gravel pack by soaking it in a liquid solution of the chemical.

Swan, P.G.

1982-04-06

93

Cause of high variability in drug dissolution testing and its impact on setting tolerances  

Microsoft Academic Search

Considering a variable mixing\\/stirring and flow pattern in a drug dissolution vessel as a likely source of high variability in results, experiments were conducted using USP paddle apparatus by placing (aligned to the walls) a metal strip (1.7 mm thick×6.4 mm wide) in a dissolution vessel. The metal strip forces the undisintegrated tablet to settle about 3 mm away from

Saeed A Qureshi; Javad Shabnam

2001-01-01

94

Initial results from dissolution rate testing of N-Reactor spent fuel over a range of potential geologic repository aqueous conditions  

SciTech Connect

Hanford N-Reactor spent nuclear fuel (HSNF) may ultimately be placed in a geologic repository for permanent disposal. To determine whether the engineered barrier system that will be designed for emplacement of light-water-reactor (LWR) spent fuel will also suffice for HSNF, aqueous dissolution rate measurements were conducted on the HSNF. The purpose of these tests was to determine whether HSNF dissolves faster or slower than LWR spent fuel under some limited repository-relevant water chemistry conditions. The tests were conducted using a flowthrough method that allows the dissolution rate of the uranium matrix to be measured without interference by secondary precipitation reactions that would confuse interpretation of the results. Similar tests had been conducted earlier with LWR spent fuel, thereby allowing direct comparisons. Two distinct corrosion modes were observed during the course of these 12 tests. The first, Stage 1, involved no visible corrosion of the test specimen and produced no undissolved corrosion products. The second, Stage 2, resulted in both visible corrosion of the test specimen and left behind undissolved corrosion products. During Stage 1, the rate of dissolution could be readily determined because the dissolved uranium and associated fission products remained in solution where they could be quantitatively analyzed. The measured rates were much faster than has been observed for LWR spent fuel under all conditions tested to date when normalized to the exposed test specimen surface areas. Application of these results to repository conditions, however, requires some comparison of the physical conditions of the different fuels. The surface area of LWR fuel that could potentially be exposed to repository groundwater is estimated to be approximately 100 times greater than HSNF. Therefore, when compared on the basis of mass, which is more relevant to repository conditions, the HSNF and LWR spent fuel dissolve at similar rates.

Gray, W.J.; Einziger, R.E.

1998-04-01

95

Development of a Rapid, Economical and Safe Method, for the Dissolution of Particulate Beryllium, for Atomic Absorption Spectrophotometry  

Microsoft Academic Search

Current methods, for the dissolution of particulate beryllium, on static, surface smear or personal air sampler (PAS) filter papers, have, as drawbacks, high acid emissions, the risk of acid burns to staff, the possibility of perchloric acid induced explosions and a high labour requirement, because they rely on digestion of samples by concentrated strong acids.An alternative method is presented, which

T. J. Miller

1991-01-01

96

Biorelevant Dissolution Testing to Predict the Plasma Profile of Lipophilic Drugs After Oral Administration  

Microsoft Academic Search

Purpose. To quantitatively compare in vitro dissolution data in biorelevant and compendial media, to investigate whether in vitro differences are reflected in the simulated plasma profile and to specify under which circumstances prediction of the plasma profile of orally administered lipophilic drugs can be achieved.

Eleftheria Nicolaides; Moira Symillides; Jennifer B. Dressman; Christos Reppas

2001-01-01

97

Simulating the postprandial stomach: physiological considerations for dissolution and release testing.  

PubMed

Food effects on drug release and absorption from solid oral dosage forms are a common biopharmaceutical problem. The fed state is characterized by different motility and secretory activity of the complete gastrointestinal (GI) tract compared to fasting conditions. Due to long gastric transit times, the postprandial stomach plays an essential role for drug release and the appearance of food effects. Therefore, a concise comprehension of the relationship between food intake and its effect on drug release from solid oral dosage forms is essential to understand their dissolution behavior under fed conditions. This review describes important aspects of stomach physiology occurring after meal ingestion with particular reference to the FDA standard breakfast. A brief overview of oral and gastric food processing and their potential influence on drug release is given. The key factors affecting the intragastric dissolution of solid oral dosage forms and their regional distribution in the stomach are discussed. Additionally, the effects of food properties on gastric emptying kinetics are presented. Mechanical aspects such as intragastric pressures and hydrodynamics caused by gastric peristalsis are defined. The initial state and the dynamic changes of the gastric content during digestion are characterized since the different physicochemical aspects such as pH value, buffer capacity, rheological properties or surface tension may be essential for the in vivo dissolution profiles of oral dosage forms. Possible effects of the discrete interplay of the physiological factors on the in vivo drug delivery behavior of solid oral dosage forms are discussed. PMID:23506381

Koziolek, Mirko; Garbacz, Grzegorz; Neumann, Marco; Weitschies, Werner

2013-04-01

98

Development and validation of spectrophotometric method for simultaneous estimation of paracetamol and lornoxicam in different dissolution media  

PubMed Central

Background: Paracetamol and lornoxicam in combined tablet dosage form are available in the market. This combination is used to treat inflammatory diseases of the joints, osteoarthritis and sciatica. Spectrophotometric and high performance liquid chromatography (HPLC) methods have been reported for their simultaneous estimation in tablet dosage form in specific solvent. This paper presents simple, accurate and reproducible spectrophotometric method for simultaneous determination of paracetamol and lornoxicam in tablet dosage form in different dissolution media. The reported method is helpful in determination of paracetamol and lornoxicam during dissolution study. Materials and Methods: Simple, sensitive, accurate and economical spectrophotometric method based on an absorption correction equation was developed for the estimation of paracetamol and lornoxicam simultaneously in tablet dosage form in different dissolution media at different pH. Results: Paracetamol showed absorption maxima at 243 nm in 0.1N HCland phosphate buffer pH 6.8, while lornoxicam showed absorption maxima at 374 nm in 0.1N HCland phosphate buffer pH 6.8. The linearity was obtained in the concentration range of 4-12 ?g/ml for paracetamol and 4-16 ?g/ ml for lornoxicam. Discussion: The concentrations of the drugs were determined by an absorption correction equation method. The results of analysis have been validated statistically by recovery studies.

Patel, Dasharath M.; Sardhara, Bhavesh M.; Thumbadiya, Diglesh H.; Patel, Chhagan N.

2012-01-01

99

A method for testing denture adhesives.  

PubMed

An in vitro test is described that simulates the in vivo fate of a denture adhesive, namely destruction, dilution, and dissolution of the adhesive, by repeated measurement of tensile bond strength for the adhesive in isotonic saline over time. The bond strengths were measured under two different settings of the testing machine. The main compositions of three denture adhesive pastes, Fittydent, Fixodent, and Super Poli-Grip and one powder adhesive, Super Wernet's, were determined by infrared spectroscopy. The tensile bond strengths of these adhesives and those of pure tragacanth gum were subjected to a three-way analysis of variance. The Fittydent and Super Poli-Grip adhesives exhibited the best results over time. The most appropriate of the described methods for testing denture adhesives seem useful; however, when seen in relation to the results of a published clinical study where the patients were asked to evaluate the retention and the duration of some of these adhesives, there are indications that the clinical validity of the method might be improved if paste adhesives are tested at temperatures above 35 degrees C. PMID:7658401

Koppang, R; Berg, E; Dahm, S; Real, C; Fløystrand, F

1995-05-01

100

Development and application of a validated HPLC method for the analysis of dissolution samples of levothyroxine sodium drug products.  

PubMed

A rapid, selective, and sensitive gradient HPLC method was developed for the analysis of dissolution samples of levothyroxine sodium tablets. Current USP methodology for levothyroxine (L-T(4)) was not adequate to resolve co-elutants from a variety of levothyroxine drug product formulations. The USP method for analyzing dissolution samples of the drug product has shown significant intra- and inter-day variability. The sources of method variability include chromatographic interferences introduced by the dissolution media and the formulation excipients. In the present work, chromatographic separation of levothyroxine was achieved on an Agilent 1100 Series HPLC with a Waters Nova-pak column (250 mm × 3.9 mm) using a 0.01 M phosphate buffer (pH 3.0)-methanol (55:45, v/v) in a gradient elution mobile phase at a flow rate of 1.0 mL/min and detection UV wavelength of 225 nm. The injection volume was 800 ?L and the column temperature was maintained at 28°C. The method was validated according to USP Category I requirements. The validation characteristics included accuracy, precision, specificity, linearity, and analytical range. The standard curve was found to have a linear relationship (r(2)>0.99) over the analytical range of 0.08-0.8 ?g/mL. Accuracy ranged from 90 to 110% for low quality control (QC) standards and 95 to 105% for medium and high QC standards. Precision was <2% at all QC levels. The method was found to be accurate, precise, selective, and linear for L-T(4) over the analytical range. The HPLC method was successfully applied to the analysis of dissolution samples of marketed levothyroxine sodium tablets. PMID:20947276

Collier, J W; Shah, R B; Bryant, A R; Habib, M J; Khan, M A; Faustino, P J

2010-10-13

101

New Accelerated Corrosion Test Methods.  

National Technical Information Service (NTIS)

A project which established accelerated corrosion test methods for conventional Al and new AlLi alloys and surface protection schemes is described. New accelerated testing methods will allow the selection of material and protection schemes with increased ...

U. Koch T. Hack

1991-01-01

102

Validation and application of a new reversed phase HPLC method for in vitro dissolution studies of rabeprazole sodium in delayed-release tablets.  

PubMed

The purpose of this study was to develop and validate a new reversed phase high performance liquid chromatographic (RP-HPLC) method to quantify in vitro dissolution assay of rabeprazole sodium in pharmaceutical tablet dosage form. Method development was performed on C 18, 100 × 4.6?mm ID, and 10? ? m particle size column, and injection volume was 20? ? L using a diode array detector (DAD) to monitor the detection at 280?nm. The mobile phase consisted of buffer: acetonitrile at a ratio of 60?:?40 (v/v), and the flow rate was maintained at 1.0?mL/min. The method was validated in terms of suitability, linearity, specificity, accuracy, precision, stability, and sensitivity. Linearity was observed over the range of concentration 0.05-12.0? ? g/mL, and the correlation coefficient was found excellent >0.999. The method was specific with respect to rabeprazole sodium, and the peak purity was found 99.99%. The method was precise and had relative standard deviations (RSD) less than 2%. Accuracy was found in the range of 99.9 to 101.9%. The method was robust in different variable conditions and reproducible. This proposed fast, reliable, cost-effective method can be used as quality control tool for the estimation of rabeprazole sodium in routine dissolution test analysis. PMID:24062966

Nawaz, Md Saddam

2013-08-22

103

Validation and Application of a New Reversed Phase HPLC Method for In Vitro Dissolution Studies of Rabeprazole Sodium in Delayed-Release Tablets  

PubMed Central

The purpose of this study was to develop and validate a new reversed phase high performance liquid chromatographic (RP-HPLC) method to quantify in vitro dissolution assay of rabeprazole sodium in pharmaceutical tablet dosage form. Method development was performed on C 18, 100 × 4.6?mm ID, and 10??m particle size column, and injection volume was 20??L using a diode array detector (DAD) to monitor the detection at 280?nm. The mobile phase consisted of buffer: acetonitrile at a ratio of 60?:?40 (v/v), and the flow rate was maintained at 1.0?mL/min. The method was validated in terms of suitability, linearity, specificity, accuracy, precision, stability, and sensitivity. Linearity was observed over the range of concentration 0.05–12.0??g/mL, and the correlation coefficient was found excellent >0.999. The method was specific with respect to rabeprazole sodium, and the peak purity was found 99.99%. The method was precise and had relative standard deviations (RSD) less than 2%. Accuracy was found in the range of 99.9 to 101.9%. The method was robust in different variable conditions and reproducible. This proposed fast, reliable, cost-effective method can be used as quality control tool for the estimation of rabeprazole sodium in routine dissolution test analysis.

Nawaz, Md. Saddam

2013-01-01

104

Dissolution of cellulose in ionic liquids as a way to obtain test materials for metal-ion detection.  

PubMed

Cellulose films containing entrapped analytical reagents suitable for metal-ion detection are produced by joint dissolution of cellulose and the reagents in ionic liquids then precipitation with water. The conditions of preparation of these test materials have been optimized and their properties have been studied. The film obtained by use of the ionic liquid 1-butyl-3-methylimidazolium chloride and 1-(2-pyridylazo)-2-naphthol has been used for colorimetric determination of divalent zinc, manganese, and nickel with detection limits at the 10(-6) mol L-1 level. PMID:17242885

Egorov, Vladimir M; Smirnova, Svetlana V; Formanovsky, Andrey A; Pletnev, Igor V; Zolotov, Yury A

2007-01-23

105

Comparison of Tracking Test Methods  

Microsoft Academic Search

A selection of epoxy specimens has been subjected to a number of different tests for track resistance. The degree of agreement between testing agencies using the same method, and between the different test methods is described. Generally speaking, those methods, which impose alternate wet-dry cycles, or otherwise simulate the \\

Mo Kurtz

1971-01-01

106

METHOD FOR TESTING COATINGS  

DOEpatents

A method is described for detecting pin hole imperfections in coatings on uranium-metal objects. Such coated objects are contacted with a heated atmosphere of gaseous hydrogen and imperfections present in the coatings will allow the uranlum to react with the hydrogen to form uranium hydride. Since uranium hydride is less dense than uranium metal it will swell, causing enlargement of the coating defeot and rendering it visible.

Johns, I.B.; Newton, A.S.

1958-09-01

107

Test methods: anabolics  

Microsoft Academic Search

In the International Olympic Committee (IOC) accredited laboratories, specific methods have been developed to detect anabolic steroids in athletes' urine. The technique of choice to achieve this is gas-chromatography coupled with mass spectrometry (GC-MS). In order to improve the efficiency of anti-doping programmes, the laboratories have defined new analytical strategies. The final sensitivity of the analytical procedure can be improved

Martial Saugy; Christine Cardis; Neil Robinson; Carine Schweizer

2000-01-01

108

Fabrication of quercetin nanoparticles by anti-solvent precipitation method for enhanced dissolution  

Microsoft Academic Search

The aim of this study was to enhance the dissolution rate of a poorly water-soluble drug quercetin by fabricating its nanoparticles with anti-solvent precipitation using the syringe pump and to investigate the effect of drug concentration, solvent to anti-solvent (S\\/AS) ratio, stirring speed and flow rate on the particle size. Characterization of the original quercetin powder and nanoparticles made by

Mitali Kakran; Nanda Gopal Sahoo; Lin Li; Zaher Judeh

109

Development and validation of a method for simultaneous estimation of ofloxacin and ornidazole in different dissolution media  

PubMed Central

Introduction: Ofloxacin and ornidazole in a combined tablet dosage form is available in the market. This combination has gained increasing acceptance in diarrhea caused due to bacterial and protozoal infections. Ofloxacin and ornidazole are also combined in the capsule dosage form to modify its release pattern in different studies. Spectrophotometric and HPTLC methods have been reported for their simultaneous estimation in the tablet dosage form in specific solvents. This paper presents a simple, accurate, and reproducible spectrophotometric method for simultaneous estimation of ofloxacin and ornidazole in the tablet dosage form in different dissolution media. The reported method is helpful in determination of ofloxacin and ornidazole during a dissolution study. Materials and Methods: A simple, sensitive, accurate, and economical spectrophotometric method based on the simultaneous equation was developed for the estimation of ornidazole and ofloxacin simultaneously in the tablet or capsule dosage form in different dissolution media at different pH values. Results: Ofloxacin showed absorption maxima at 294 nm in 0.1 N HCl and at 287 nm in phosphate buffer pH 6.8 and phosphate buffer pH 7.4 while ornidazole showed absorption maxima at 277 nm in 0.1 N HCl and at 319 nm in two buffers, respectively. The linearity was obtained in the concentration range of 1–8 ?g/ ml for ofloxacin and 4–26 ?g/ml for ornidazole. Discussion: The concentrations of the drugs were determined by the simultaneous equation method. The results of analysis have been validated statistically and by recovery studies.

Patel, Dasharath M.; Soneji, Jignesh A.; Patel, Parth B.; Patel, Chhagan N.

2012-01-01

110

Column leach study III: Effects of sampling location, sampling methods, and chemical abatement treatments on the dissolution of metals in gold-copper mine tailings  

Microsoft Academic Search

Metal dissolution from tailings collected at a gold-copper mine mill site was examined by researchers from the U.S. Bureau\\u000a of Mines using column leaching procedures and on-site field monitoring wells. The 3-year laboratory study reviewed effects\\u000a of column waste depths, dry cycles, waste sampling locations, and metal dissolution abatement techniques. Results of the laboratory\\u000a testing indicated that the concentrations of

Richard D. Doepker

1994-01-01

111

Gallstone dissolution.  

PubMed

Many methods are available for gallstone dissolution, including oral bile salts; cholesterol solvents such as mono-octanoin or methyl tert-butyl either; and calcium or pigment solvents such as EDTA and polysorbate. Which of these approaches will be appropriate for an individual patient depends on the type of stones; whether they are in the gallbladder or the bile ducts; whether access to the biliary tree is available; the patient's age and general medical condition; and the availability of necessary expertise. In the US, both chenodeoxycholate and ursodeoxycholate are now available. Ursodeoxycholate is more expensive but appears to produce fewer side effects and may be more efficacious. These agents are most effective in thin women with small floating, radiolucent cholesterol stones in a functioning gallbladder. Only about half of the small subset of patients will experience partial or complete dissolution of stones within a year. Stone recurrence and the potential toxicity of long-term therapy are problems with this approach. Therefore, for most patients, cholecystectomy, either in the traditional fashion or using a laparoscopic approach (see article later in this issue by Gadacz et al), is the most cost-effective and perhaps the safest option. Intragallbladder instillation of methyl tert-butyl ether probably will be applicable only to a small subset of patients, and treatment is likely to be followed by a high recurrence rate. In patients with retained common duct cholesterol stones and access to the biliary tree, mono-octanoin therapy is advantageous in that it can be initiated as soon as cholangiography demonstrates no extravasation. In properly selected patients, a 90% success rate with this technique can be expected within 7 days. PMID:2247812

Talamini, M A; Gadacz, T R

1990-12-01

112

Dissolution kinetics of nanocrystals.  

PubMed

A simple series of test-tube experiments is all it takes to quantify a largely neglected nano-effect responsible for a dramatic increase-by orders of magnitude-in the surface-area-normalized rate of dissolution of nanocrystals. Though the observed variation in this specific rate as a function of size is unprecedented, the effect may be rationalized in terms of the classic atomistic theory of crystal growth and dissolution. PMID:23649865

Petrik, Marek; Harbrecht, Bernd

2013-05-03

113

Fabrication of fenofibrate nanocrystals by probe sonication method for enhancement of dissolution rate and oral bioavailability.  

PubMed

Fenofibrate (FBT) is lipophillic drug used in hypercholesterolemia and hypertriglyceridemia having logP 5.375, low solubility (practically insoluble in water) and low oral bioavailability (36%). The purpose of work was to develop FBT nanocrystals for the enhancement of solubility and oral bioavailability. Fenofibrate nanosuspension was prepared using probe sonicator and transformed into dry powder using freeze drying and characterized by DSC, FTIR, XRPD, SEM, particle size, polydispersity index (PDI), zeta potential, solubility, in vitro dissolution, in vivo bioavailability and stability studies. Formulation FNS3 and pure drug exhibited the in vitro dissolution about 73.89% and 8.53% in 1% sodium lauryl sulfate (SLS) media, respectively. When the particle size reduced from 80,000±923nm to 460±20nm, saturation solubility was significantly increased. The saturation solubility of formulation FNS3 in 0.5% and 1% of SLS media found to be 67.51±1.5?g/mL and 107±1.9?g/mL, respectively. While, the saturation solubility of pure drug in 0.5% and 1% of SLS was found to be 6.02±1.51?g/ml and 23.54±1.54?g/ml, respectively. The pharmacokinetic study of optimized nanocrystals (FNS3) conducted in New Zealand white rabbits showed 4.73-fold increase in relative bioavailability than that of pure drug. Long term stability studies showed that there was no significant change in the mean particle size and PDI at 5°C±3°C after 180 days. This enhanced dissolution and bioavailability of fenofibrate nanocrystals could be the promising approach for oral delivery. PMID:23602990

Ige, Pradum Pundlikrao; Baria, Rohan K; Gattani, Surendra G

2013-03-23

114

Regulatory status on the role of in vitro dissolution testing in quality control and biopharmaceutics in Europe.  

PubMed

An overview is provided regarding the different use of in vitro dissolution and particular related regulatory aspects. The overview attempts to clarify the regulatory requirements in all contexts in which in vitro dissolution data are employed. The different areas comprise the development of new and generic products as well as bioequivalence between different formulations. In vitro dissolution is no longer one issue among others in terms of specifications and batch release only, but is aimed to be a relevant tool for describing biopharmaceutic product characteristics for different purposes in the regulatory environment. Accordingly, the extent of the experiments will depend on the purpose of the in vitro dissolution data. PMID:23585295

Limberg, Jobst; Potthast, Henrike

2013-06-04

115

Enhancement of the dissolution rate and bioavailability of fenofibrate by a melt-adsorption method using supercritical carbon dioxide  

PubMed Central

Background: The aim of this study was to enhance the bioavailability of fenofibrate, a poorly water-soluble drug, using a melt-adsorption method with supercritical CO2. Methods: Fenofibrate was loaded onto Neusilin® UFL2 at different weight ratios of fenofibrate to Neusilin UFL2 by melt-adsorption using supercritical CO2. For comparison, fenofibrate-loaded Neusilin UFL2 was prepared by solvent evaporation and hot melt-adsorption methods. The fenofibrate formulations prepared were characterized by differential scanning calorimetry, powder x-ray diffractometry, specific surface area, pore size distribution, scanning electron microscopy, and energy-dispersive x-ray spectrometry. In vitro dissolution and in vivo bioavailability were also investigated. Results: Fenofibrate was distributed into the pores of Neusilin UFL2 and showed reduced crystal formation following adsorption. Supercritical CO2 facilitated the introduction of fenofibrate into the pores of Neusilin UFL2. Compared with raw fenofibrate, fenofibrate from the prepared powders showed a significantly increased dissolution rate and better bioavailability. In particular, the area under the drug concentration-time curve and maximal serum concentration of the powders prepared using supercritical CO2 were 4.62-fold and 4.52-fold greater than the corresponding values for raw fenofibrate. Conclusion: The results of this study highlight the usefulness of the melt-adsorption method using supercritical CO2 for improving the bioavailability of fenofibrate.

Cha, Kwang-Ho; Cho, Kyung-Jin; Kim, Min-Soo; Kim, Jeong-Soo; Park, Hee Jun; Park, Junsung; Cho, Wonkyung; Park, Jeong-Sook; Hwang, Sung-Joo

2012-01-01

116

SB5 WITH THE ESTIMATED IMPACT OF LOW TEMPERATURE ALUMINUM DISSOLUTION: PRELIMINARY FRITS FOR MELT RATE TESTING  

SciTech Connect

Composition projections for Sludge Batch 5 (SB5) were developed to evaluate possible impacts of the Al-dissolution process on the availability of viable frit compositions for vitrification at the DWPF. The study included two projected SB5 compositions that bound potential outcomes (or degrees of effectiveness) of the Al-dissolution process, as well as a nominal SB5 composition projection based on the results of the recent Al-dissolution demonstration at SRNL. A Nominal Stage assessment was used to evaluate the two SB5 projections combined with an array of 19,305 frit compositions over a range of waste loading (WL) values against the DWPF process control models. The Nominal Stage results allowed for the down-selection of a small number of frits that provided reasonable projected operating windows (typically 25 to 40 wt %) and permitted some compositional flexibility (i.e., the ability to further tailor the frit to improve melt rate). Variation Stage assessments were then performed using the down-selected frits and the two SB5 composition projections with variation applied to each sludge component. The Variation Stage results showed that the operating windows were somewhat reduced in width, as expected when sludge variation is applied. Three of the down-selected frits continued to perform well for both SB5 projections through the Variation Stage, providing WL windows of approximately 26 to 35 wt %. The maximum WLs were limited by a processing constraint, TL, rather than a waste form affecting constraint (e.g., nepheline crystallization) in the Variation Stage assessments. Subsequent Nominal Stage assessments were performed with an updated SB5 projection based on the results of the Al-dissolution demonstration performed in the SRNL Shielded Cells facility (representing 40% removal of Al). The three frits identified in the earlier paper studies continued to perform well with this updated projection. The available operating windows were slightly wider, although maximum WL was limited by both the TL and nepheline constraints for all three frits. Changes in the projected SB5 composition are anticipated before processing begins at the DWPF, which will likely require additional paper study assessments as well as experimental frit development studies. This study identifies several frits which provide insight into potential operating windows for SB5 vitrification in DWPF. However, until experimental studies can be performed to gain information on melt rate and other parameters needed to optimize frit selection, no final frit recommendation can be made. Information regarding melt rate cannot be inferred from the paper study results. Experimental studies to evaluate this critical factor in DWPF processing must be performed to support frit optimization for any projected sludge composition. Five frit compositions were identified for melt rate testing at SRNL with simulated SB5 Case F SRAT product. The results of these tests will be used to evaluate the impact of the frit components--particularly B{sub 2}O{sub 3} and Na{sub 2}O--that are expected to influence melt rate for SB5-like sludges. The results of the melt rate testing will be documented in a separate report and will be used to help guide the frit recommendation process as the final SB5 composition becomes clearer.

Fox, K; Tommy Edwards, T

2008-03-11

117

Cellulose in lithium chloride\\/ N, N-dimethylacetamide, optimisation of a dissolution method using paper substrates and stability of the solutions  

Microsoft Academic Search

Activation and dissolution in lithium chloride\\/N,N-dimethylacetamide (LiCl\\/DMAc) of cellulose from paper substrates are studied. The importance of the multiple parameters involved such as salt concentration, sample source and preparation is shown in a literature review. The experiments are carried out in order to perfect the method of activation and dissolution of paper containing different kinds of additives, typically found in

Anne-Laurence Dupont

2003-01-01

118

Cosolvent Evaporation Method for Enhancement of Solubility and Dissolution Rate of Poorly Aqueous Soluble Drug Simvastatin: In vitro – In vivo Evaluation  

Microsoft Academic Search

A number of synthesized chemical molecules suffer from low aqueous solubility problems. Enhancement of aqueous solubility,\\u000a dissolution rate, and bioavailability of drug is a very challenging task in drug development. In the present study, solubility\\u000a and dissolution of poorly aqueous soluble drug simvastatin (SIM) was enhanced using hydrophilic, low viscosity grade polymer\\u000a hydroxypropyl methylcellulose (HPMC K3LV). The co-solvent evaporation method

Priyanka Pandya; Surendra Gattani; Pankaj Jain; Lokesh Khirwal; Sanjay Surana

2008-01-01

119

Experimental Methods for Subjective Testing.  

National Technical Information Service (NTIS)

Subjective tests have been an important source of information concerning the response of the ear to sound stimuli for at least sixty years, the methods used differing as widely as the results obtained. The report reviews subjective test work to date, with...

D. W. Birden

1990-01-01

120

The USP Performance Verification Test, Part I: USP Lot P Prednisone Tablets—Quality Attributes and Experimental Variables Contributing to Dissolution Variance  

Microsoft Academic Search

Purpose  Beyond instrumental qualification, proficiency testing is not usually a prerequisite for many analytical procedures, given\\u000a reliance on a manufacturer’s assay validation coupled with regulatory review and inspection. Given the special features of\\u000a the dissolution procedure, proficiency testing was put in place initially by pharmaceutical manufacturers and carried on by\\u000a USP. Proficiency testing is designed to help ensure that execution of

Gang Deng; Alyssa J. Ashley; William E. Brown; Joseph W. Eaton; Walter W. Hauck; Loice C. Kikwai; Mark R. Liddell; Ronald G. Manning; Jimmy M. Munoz; Pallavi Nithyanandan; Maria J. Glasgow; Erika Stippler; Samir Z. Wahab; Roger L. Williams

2008-01-01

121

Salt Dissolution in Oil and Gas Test Holes in Central Kansas. Part II. Salt Dissolution in Oil and Gas Test Holes in the Gorham Oilfield, Russell County, Central Kansas.  

National Technical Information Service (NTIS)

Within the Gorham Oilfield, there are two areas of surface subsidence caused by salt dissolution in three abandoned oil wells. Since these subsidence areas seriously affect Interstate Highway 70, they were carefully surveyed and studied. The Crawford Sink...

R. F. Walters

1975-01-01

122

Thermal well-test method  

DOEpatents

A well-test method involving injection of hot (or cold) water into a groundwater aquifer, or injecting cold water into a geothermal reservoir. By making temperature measurements at various depths in one or more observation wells, certain properties of the aquifer are determined. These properties, not obtainable from conventional well test procedures, include the permeability anisotropy, and layering in the aquifer, and in-situ thermal properties. The temperature measurements at various depths are obtained from thermistors mounted in the observation wells.

Tsang, Chin-Fu (Albany, CA); Doughty, Christine A. (Berkeley, CA)

1985-01-01

123

Methods for testing transport models  

SciTech Connect

Substantial progress has been made over the past year on six aspects of the work supported by this grant. As a result, we have in hand for the first time a fairly complete set of transport models and improved statistical methods for testing them against large databases. We also have initial results of such tests. These results indicate that careful application of presently available transport theories can reasonably well produce a remarkably wide variety of tokamak data.

Singer, C.; Cox, D.

1991-11-14

124

[Inappropriate test methods in allergy].  

PubMed

Inappropriate test methods are increasingly utilized to diagnose allergy. They fall into two categories: I. Tests with obscure theoretical basis, missing validity and lacking reproducibility, such as bioresonance, electroacupuncture, applied kinesiology and the ALCAT-test. These methods lack both the technical and clinical validation needed to justify their use. II. Tests with real data, but misleading interpretation: Detection of IgG or IgG4-antibodies or lymphocyte proliferation tests to foods do not allow to separate healthy from diseased subjects, neither in case of food intolerance, allergy or other diagnoses. The absence of diagnostic specificity induces many false positive findings in healthy subjects. As a result unjustified diets might limit quality of life and lead to malnutrition. Proliferation of lymphocytes in response to foods can show elevated rates in patients with allergies. These values do not allow individual diagnosis of hypersensitivity due to their broad variation. Successful internet marketing, infiltration of academic programs and superficial reporting by the media promote the popularity of unqualified diagnostic tests; also in allergy. Therefore, critical observation and quick analysis of and clear comments to unqualified methods by the scientific medical societies are more important than ever. PMID:20963379

Kleine-Tebbe, J; Herold, D A

2010-11-01

125

Velocity profiles and shear strain rate variability in the USP Dissolution Testing Apparatus 2 at different impeller agitation speeds.  

PubMed

The fluid velocity profiles at different locations inside a standard USP Dissolution Testing Apparatus 2 were experimentally obtained via Laser Doppler Velocimetry (LDV) at three impeller agitations speeds, namely 50rpm, 75rpm and 100rpm. The experimental results were compared with the predictions obtained with Computational Fluid Dynamics (CFD) where the ?-? model with low Reynolds number correction was used to account for turbulence effects. In general, good agreement was found between the experimental LDV velocity measurements and the CFD simulation predictions. The non-dimensional tangential, axial and radial velocity profiles (scaled with the impeller tip speed) and the flow pattern were found to be nearly independent of the agitation speed in most regions of the vessel, implying that increasing the agitation speed generally produced a corresponding increase in the local values of the velocity. However, the velocity profiles and flow pattern in the inner core region just below the impeller, where the dissolving tablet is usually located, were found to be much less sensitive to agitation speed. In this region, the axial and radial velocities were especially low and were not significantly affected by agitation increases. This inner core region at the center of the vessel bottom persisted irrespective of agitation intensity. The CFD predictions also indicated that increasing the agitation speed resulted in a higher shear strain rate distribution along the vessel bottom, although the strain rate was always very low at the center of the vessel bottom, even when the agitation speed was increased. PMID:20883758

Bai, Ge; Wang, Yimin; Armenante, Piero M

2010-09-29

126

The dissolution of cellulose in NaOH-based aqueous system by two-step process  

Microsoft Academic Search

A new dissolution method, a two-step process, for cellulose in NaOH\\/urea aqueous system was investigated with 13C NMR, wide X-ray diffraction (WXRD), and solubility test. The two steps were as follows: (1) formation and swelling of a\\u000a cellulose–NaOH complex and (2) dissolution of the cellulose–NaOH complex in aqueous urea solution. The dissolution mechanism\\u000a could be described as strong interaction between

Haisong Qi; Quanling Yang; Lina Zhang; Tim Liebert; Thomas Heinze

2011-01-01

127

Thermal well-test method  

DOEpatents

A well-test method involving injection of hot (or cold) water into a groundwater aquifer, or injecting cold water into a geothermal reservoir is disclosed. By making temperature measurements at various depths in one or more observation wells, certain properties of the aquifer are determined. These properties, not obtainable from conventional well test procedures, include the permeability anisotropy, and layering in the aquifer, and in-situ thermal properties. The temperature measurements at various depths are obtained from thermistors mounted in the observation wells.

Tsang, C.F.; Doughty, C.A.

1984-02-24

128

Dissolution behavior of FFTF fuel  

Microsoft Academic Search

These tests, using FFTF fuel, show that fuel fragmentation and dislodgement from the cladding occurs rather early in the dissolution. The large surface areas of the fuel fragments will lead to rapid dissolution, certainly more rapid than would be expected if the fuel remained within the cladding and dissolved from the open ends, as is sometimes assumed.

D. O. Campbell; J. C. Mailen; R. L. Fellows

1984-01-01

129

Dissolution profiles in column dissolution.  

PubMed

A self-consistent model for open-ended column dissolution is presented. It is shown that when the concentration of the efflux stream from the column is plotted versus time, then the profile is fairly level at first and then drops rapidly, in the form of an inverse sigmoid profile. The model assumes that the particles are isometric and that they adhere to a Levich type particulate dissolution, and it is based on plug flow with a given residence time. Consistency is shown between the plug flow parameter (Q2) and experimental data. Good correlation is found between predicted and experimental profiles. PMID:3772748

Carstensen, J T; Yonezawa, Y

1986-08-01

130

HEPA filter dissolution process  

DOEpatents

This invention is comprised of a process for dissolution of spent high efficiency particulate air (HEPA) filters and then combining the complexed filter solution with other radioactive wastes prior to calcining the mixed and blended waste feed. The process is an alternate to a prior method of acid leaching the spent filters which is an inefficient method of treating spent HEPA filters for disposal.

Brewer, K.N.; Murphy, J.A.

1992-12-31

131

Method For Testing Properties Of Corrosive Lubricants  

DOEpatents

A method of testing corrosive lubricating media using a wear testing apparatus without a mechanical seal. The wear testing apparatus and methods are effective for testing volatile corrosive lubricating media under pressure and at high temperatures.

Ohi, James (Denver, CO); De La Cruz, Jose L. (San Antonio, TX); Lacey, Paul I. (Wexford, IE)

2006-01-03

132

Spectrophotometric simultaneous determination of Tenofovir disoproxil fumarate and Emtricitabine in combined tablet dosage form by ratio derivative, first order derivative and absorbance corrected methods and its application to dissolution study.  

PubMed

Three simple, economical, precise, and accurate methods are described for the simultaneous determination of Tenofovir disoproxil fumarate (TE) and Emtricitabine (EM) in combined tablet dosage form. The first method is ratio derivative spectra, second is first-order derivative spectrophotometry and third is absorption corrected method. The amplitudes at 271.07 and 302.17 nm in the ratio derivative method, 224.38 and 306.88 nm in the first order derivative method were selected to determine Tenofovir disoproxil fumarate (TE) and Emtricitabine (EM), respectively, in combined formulation. Beer's law is obeyed in the concentration range of 3-21 ?g/ml for TE and 2-14 ?g/ml for EM for first two methods and range for third method was 6-30 ?g/ml of TE and 4-20 ?g/ml of EM. The percent assay for commercial formulation was found to be in the range 98.91%-101.72% for both the analytes by the proposed three methods. Absorption corrected method was successfully applied to carry out dissolution study of commercial tablet formulation by using USP II dissolution test apparatus. The methods were validated with respect to linearity, precision, and accuracy. Recoveries by proposed methods were found in the range of 99.06 %-101.34 % for both the analytes. PMID:23781430

Choudhari, Vishnu P; Ingale, Snehal; Gite, Sacchidanand R; Tajane, Dipali D; Modak, Vikram G; Ambekar, Archana

2011-01-01

133

Methods for Equating Mental Tests.  

National Technical Information Service (NTIS)

The technology for test equating has arisen from the need to make new tests comparable to old ones. The equating of military tests has two objectives: (a) to make scores on different tests forms and on different composites of test forms comparable, and at...

K. A. Gialluca L. I. Crichton C. D. Vale

1984-01-01

134

SELECTIVE SEPARATION OF URANIUM FROM THORIUM, PROTACTINIUM AND FISSION PRODUCTS BY PEROXIDE DISSOLUTION METHOD  

DOEpatents

A method is described for separating U/sup 233/ from thorium and fission products. The separation is effected by forming a thorium-nitric acid solution of about 3 pH, adding hydrogen peroxide to precipitate uranium and thorium peroxide, treating the peroxides with sodium hydroxide to selectively precipitate the uranium peroxide, and reacting the separated solution with nitric acid to re- precipitate the uranium peroxide.

Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

1959-08-18

135

K Basin Sludge Conditioning Process Testing Fate of PCBs During K Basin Sludge Dissolution in Nitric Acid and with Hydrogen Peroxide Addition  

SciTech Connect

The work described in this report is part of the studies being performed to address the fate of polychlorinated biphenyls (PCBs) in K Basin sludge before the sludge can be transferred to the Tank Waste Remediation System (TWRS) double shell tanks. One set of tests examined the effect of hydrogen peroxide on the disposition of PCBs in a simulated K Basin dissolver solution containing 0.5 M nitric acid/1 M Fe(NO{sub 3}){sub 3}. A second series of tests examined the disposition of PCBs in a much stronger ({approx}10 M) nitric acid solution, similar to that likely to be encountered in the dissolution of the sludge.

GM Mong; AJ Schmidt; EW Hoppe; KH Pool; KL Silvers; BM Thornton

1999-01-04

136

Formulation Development and Dissolution Rate Enhancement of Efavirenz by Solid Dispersion Systems  

PubMed Central

The aim of this study was to enhance the dissolution rate of efavirenz using solid dispersion systems (binary and ternary). A comparison between solvent and fusion method was also investigated. Solid dispersions of efavirenz were prepared using polyethylene glycol 8000, polyvinylpyrrolidone K30 alone and combination of both. Tween 80 was incorporated to obtain a ternary solid dispersion system. Dissolution tests were conducted and evaluated on the basis of cumulative percentage drug release and dissolution efficiency. Physicochemical characterizations of the solid dispersions were carried out using differential scanning calorimetric, powder X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Dissolution was remarkably improved in both systems compared to pure efavirenz (P<0.05). An optimum ratio was identified at a drug:polymer of 1:10. Incorporation of Tween 80 to 1:10 formulations formed using solvent method showed further improvement in the dissolution rate. Physicochemical characterization results suggested that efavirenz existed in the amorphous form in all the solid dispersion systems providing evidence of improvement in dissolution. No statistically significant difference (P>0.05) in dissolution was observed between the two methods. Binary and ternary solid dispersion systems both have showed a significant improvement in the dissolution rate of efavirenz. Formulations with only polyvinylpyrrolidone K30 showed best dissolution profile and 1:10 was identified as an optimum drug-polymer weight ratio.

Koh, P. T.; Chuah, J. N.; Talekar, Meghna; Gorajana, A.; Garg, S.

2013-01-01

137

Studies on the dissolution of glucose in ionic liquids and extraction using the antisolvent method.  

PubMed

Biomass, the fibrous material derived from plant cell walls, is a potentially clean and renewable nonfood feedstock for liquid fuel and chemical production in future biorefineries. The capability of ionic liquids to act as selective solvents and catalysts for biomass processing has already been proven. Thus, they are considered as an alternative to conventional solvents. Nevertheless, phase equilibria with biomass derived compounds is still lacking in the literature. To overcome the lack of experimental data on phase equilibria of biomass carbohydrates in ionic liquids, the solubility of d-glucose in four ionic liquids was measured within a temperature range from 283 to 373 K. Solubility data were successfully correlated with local composition thermodynamic models such as NRTL and UNIQUAC. In this work, the possibility of extracting glucose from these ionic liquids using the antisolvent method has been also evaluated. The parameters affecting the extraction process are the ionic liquid type, ethanol/ionic liquid ratio, temperature, water content, and time. Results indicate that ethanol can be successfully used as an antisolvent to separate glucose from ionic liquids. PMID:23398175

Hassan, El-Sayed R E; Mutelet, Fabrice; Pontvianne, Steve; Moïse, Jean-Charles

2013-02-22

138

Percutaneous dissolution of gallstones.  

PubMed

Contact dissolution with MTBE is an effective and safe method to treat symptomatic patients with cholesterol gallstones. Personnel, time, and safety factors have limited widespread use of the procedure. With current competing methods to treat gallstones, it is likely that MTBE use will be reserved for those patients who elect percutaneous therapy due to fear of surgery or anesthesia and in those elderly patients who are compromised by underlying medical conditions. PMID:1925663

vanSonnenberg, E; D'Agostino, H B; Hofmann, A F; Sanchez, R B; Goodacre, B B; Esch, O; Casola, G

1991-07-01

139

Solubility and dissolution improvement of Rofecoxib using solid dispersion technique.  

PubMed

Rofecoxib (RXB) is a potent and selective cyclo-oxygenase-2 (COX-2) inhibitor, highly effective in the treatment of various pains, inflammatory condition, post-operative pain, rheumatoid arthritis, other musculo-skeletal and joint disorders. Although they are completely absorbed upon oral administration, the peak plasma concentration is reached 2-3 hours after oral ingestion. The reason for delay being slow rate of absorption due to poor aqueous solubility. An attempt has been made to enhance solubility and dissolution of rofecoxib by solid dispersion(SD) technique using various hydrophilic excipients like PEG 4000, PEG 6000, PVP at different ratios by melting method and solvent evaporation method. The prepared SD of RXB were characterized to various physico-chemical properties and in vitro drug dissolution studies in 0.1N HCl with 0.25% SLS (pH 1.1) media for a period of 90 min using USP XXIII electro lab 8 basket tab dissolution test apparatus using paddle. The result of study indicated that there was no drug-polymer interaction found. The drug dissolution was found to enhance percent in PEG 4000, PEG 6000 and PVP, after 90 mins of dissolution study 79.02%, 88.02%, 98.57% respectively. On comparison of various polymers used at varied concentrations PVP at 75:25 ratio by fusion method was found to be best suitable for the enhancement of dissolution and solubility of RXB. PMID:18930854

Rahamathulla, Mohamed; Hv, Gangadharappa; Rathod, Neelkant

2008-10-01

140

The Development of USP Dissolution and Drug Release Standards  

Microsoft Academic Search

Dissolution tests have been in use in the pharmaceutical industry for over 20 years, and they are official in The United States Pharmacopeia since the early 1960s. The dissolution test, reviewed primarily as a quality control tool, replaced the use of disintegration tests which had been official in The United States Pharmacopeia since 1950. Refinements in the dissolution test equipment

Jordan L. Cohen; Barbara B. Hubert; Lewis J. Leeson; Christopher T. Rhodes; Joseph R. Robinson; Theodore J. Roseman; Eli Shefter

1990-01-01

141

Precision of Selected Concrete Test Methods.  

National Technical Information Service (NTIS)

Precision statements for the following portland cement concrete test methods are presented: compressive strength, flexural strength, unit weight, air content, and ball penetration. Testing programs and analytical methods are described in detail. Wherever ...

P. E. Benson C. R. Sundquist

1976-01-01

142

Test Methods for Environment-Assisted Cracking.  

National Technical Information Service (NTIS)

The test methods for assessing environment-assisted cracking of metals in aqueous solution are described. The advantages and disadvantages are examined and the interrelationship between results from different test methods is discussed. The source of diffe...

A. Turnbull

1992-01-01

143

Advanced methods for cascade testing  

NASA Astrophysics Data System (ADS)

Considerable advances have been achieved over the last decennia in the field of cascade testing, but they were generally not reported in sufficient detail. As an example, details of transonic/supersonic cascade testing procedures were scarcely documented in literature. Many other aspects evolved considerably, originally from the progress of experimental techniques as well as from the interaction with computer data. New methodologies based on advanced instrumentation gained sufficient validation. Consequently, the Propulsion and Energetics Panel decided to initiate an AGARDograph on this subject in 1988. Since then, several authors prepared chapters for the AGARDograph, coordinated by the editor. The following chapters are included: Modeling Turbomachinery Flow Conditions, Linear Cascades, Annular Cascades, Aspects of Hot Cascades, Transient Cascade Testing, Unsteady Flow in Cascades, and 3-D Laser Anemometry in Annular Cascades.

Hirsch, Charles

1993-08-01

144

METHOD OF TESTING FOR LEAKS  

DOEpatents

A method is described for detecting minute holes In fuel element jackets. The method comprises submerging the jacketed body in an atmosphere of a radioactive gas under pressure, the radioactive emanations from said gas being sufficientiy penetratIng to penetrate the jacket of the jacketed body. After the jacketed body is removed from the radtoactive gas atmosphere, it is exannined for the presence of emanations from radioactive gas which entered the jacketed body through the minute holes. In this manner, the detectton of radioactive emanations is a positive indication that the fuel element is not perfectly sealed.

Creutz, E.C.; McAdams, Wm.A.; Foss, M.H.

1958-07-22

145

Selective dissolution of magnetic iron oxides in the acid-ammonium oxalate/ferrous iron extraction method-I. Synthetic samples  

NASA Astrophysics Data System (ADS)

In soil magnetism, the magnetic parameters alone are not always sufficient to distinguish the lithogenic from the pedogenic magnetic fractions. Sequential extraction techniques have therefore been incorporated into magnetic studies to constrain the environmental interpretation. Here we report on the dissolution behaviour of magnetite and maghemite in the acid-ammonium oxalate method to see whether the method is suitable for specific dissolution of magnetic minerals from soils and sediments. To prevent changes in the extraction mechanism during the experiments (see Appendix A), we used an adapted version of the acid-ammonium oxalate (AAO) method, in which Fe2+ is added to the extraction solution prior to the experiment [the AAO-Fe(II) method]. The procedure was divided into several 30min extraction steps to check the dissolution progress. Synthetic samples containing a quartz matrix with 0.1wt per cent of iron oxides were extracted with the AAO-Fe(II) method. The iron oxides consisted of either magnetite or maghemite with grain sizes of <0.5µm (fine grained or SD/PSD) and <5µm (coarse grained or MD/PSD), or a 1:1 mixture of both minerals. Because only magnetite and maghemite were studied, the changes in magnetic characteristics could be monitored after each extraction step by analysis of the bulk susceptibility and hysteresis parameters measured at room temperature. The AAO-Fe(II) method preferentially dissolved the smaller iron oxides from the samples. For samples containing iron oxides with coarse grain size there is a preference for dissolving maghemite rather than magnetite. Extractions of the samples containing mixtures of two different grain sizes or with different mineralogy show that the method preferentially dissolves the smaller grains before attacking the coarse grains in the sample.

van Oorschot, Ingeborg H. M.; Dekkers, Mark J.

2001-06-01

146

Pore-scale simulation of coupled reactive transport and dissolution in fractures and porous media using the level set interface tracking method  

SciTech Connect

A level set simulation methodology developed for modeling coupled reactive transport and structure evolution has been applied to dissolution in fracture apertures and porous media. The coupled processes such as fluid flow, reactant transport and dissolution at the solid-liquid interfaces are handled simultaneously. The reaction-induced evolution of solid-liquid interfaces is captured using the level set method, with the advantage of representing the interface with sub-grid scale resolution. The coupled processes are simulated for several geometric models of fractures and porous media under various flow conditions and reaction rates. Quantitative relationships between permeability and porosity are obtained from some of the simulation results and compared with analytical constitutive relations (i.e., the conventional cubic law and the Carman-Kozeny law) based on simplified pore space geometries and reaction induced geometric evolutions. The drastic deviation of the simulation results from these analytical theories is explained by the development of large local concentration gradients of reactants within fracture apertures and individual pores observed in the simulation results and consequently the complex geometric evolution patterns of fracture apertures and pores due to mineral dissolution. The simulation results support the argument that traditional constitutive relations based on simplified geometries and conditions have limited applicability in predicting field scale reactive transport and that incorporation of micro-scale physics is necessary.

Hai Huang; Xiaoyi Li

2011-01-01

147

Small-crack test methods  

Microsoft Academic Search

This book contains chapters on fracture mechanics parameters for small fatigue cracks, monitoring small-crack growth by the replication method, measurement of small cracks by photomicroscopy (experiments and analysis), and experimental mechanics of microcracks. Other topics discussed are the real-time measurement of small-crack-opening behavior using an interferometric strain\\/displacement gage; direct current electrical potential measurement of the growth of small cracks; an

James M. Larsen; John E. Allison

1992-01-01

148

Possible Precision of Statistical Insulation Test Methods  

Microsoft Academic Search

The report deals with insulation test methods where voltages of constant shape but different amplitudes are applied to a test object to determine the voltage which corresponds to a certain probability of flashover. A hypothetical test method is considered which gives the minimum statistical error in the determination of that voltage for any given number of voltage applications. It is

N. Hylten-Cavallius; F. A. Chagas

1983-01-01

149

Electrochemical Polishing of Thread Fastener Test Specimens of Nickel-Chromium Iron Alloys.  

National Technical Information Service (NTIS)

An electrochemical polishing device and method for selective anodic dissolution of the surface of the test specimens comprised, for example, of nickel-chromium-iron alloys are presented. This provides for uniform dissolution at the localized sites to remo...

A. R. Kephart

1990-01-01

150

Electrochemical polishing of thread fastener test specimens of nickel-chromium iron alloys.  

National Technical Information Service (NTIS)

An electrochemical polishing device and method for selective anodic dissolution of the surface of the test specimens comprised, for example, of nickel-chromium-iron alloys, which provides for uniform dissolution at the localized sites to remove metal thro...

A. R. Kephart

1990-01-01

151

DDSolver: An Add-In Program for Modeling and Comparison of Drug Dissolution Profiles  

PubMed Central

In recent years, several mathematical models have been developed for analysis of drug dissolution data, and many different mathematical approaches have been proposed to assess the similarity between two drug dissolution profiles. However, until now, no computer program has been reported for simplifying the calculations involved in the modeling and comparison of dissolution profiles. The purposes of this article are: (1) to describe the development of a software program, called DDSolver, for facilitating the assessment of similarity between drug dissolution data; (2) to establish a model library for fitting dissolution data using a nonlinear optimization method; and (3) to provide a brief review of available approaches for comparing drug dissolution profiles. DDSolver is a freely available program which is capable of performing most existing techniques for comparing drug release data, including exploratory data analysis, univariate ANOVA, ratio test procedures, the difference factor f1, the similarity factor f2, the Rescigno indices, the 90% confidence interval (CI) of difference method, the multivariate statistical distance method, the model-dependent method, the bootstrap f2 method, and Chow and Ki’s time series method. Sample runs of the program demonstrated that the results were satisfactory, and DDSolver could be served as a useful tool for dissolution data analysis. Electronic supplementary material The online version of this article (doi:10.1208/s12248-010-9185-1) contains supplementary material, which is available to authorized users.

Zhang, Yong; Huo, Meirong; Zou, Aifeng; Li, Weize; Yao, Chengli; Xie, Shaofei

2010-01-01

152

Interferometric test method for testing convex aspheric mirror surfaces  

NASA Astrophysics Data System (ADS)

An interferometric null Test Method is described for testing convex aspheric surfaces, such as found in secondary mirrors of Cassegrain telescopes or variations thereof such as Mersenne and Ritchey-Chrétien. A family of test designs is described covering a wide range of mirror diameters, radii of curvature, and aspheric shapes as described by conic constants and/or polynomials. The Test Method has been used successfully for testing the convex hyperboloid surface of the 244-mm diameter secondary mirror of the NASA 3-meter IRTF telescope. The Test Method is currently being used to test the 120-mm diameter, convex paraboloid secondary mirrors of the Magdalena Ridge Observatory Interferometer (MROI). Test designs exist on paper for both Keck secondary mirrors (0.53-m and 1.4-m diameter), the HST secondary (0.3-meter diameter), and secondary mirrors of some of the extremely large telescopes of the future, such as the TMT secondary (3.2-m diameter). In typical test embodiments, the simplicity of the Test enables rapid implementation at a fraction of the cost of comparable Hindle-Sphere or Hindle-Simpson tests.

McKechnie, T. Stewart

2010-07-01

153

Dissolution rates of DWPF glasses from long-term PCT.  

National Technical Information Service (NTIS)

We have characterized the corrosion behavior of several Defense Waste Processing Facility (DWPF) reference waste glasses by conducting static dissolution tests with crushed glasses. Glass dissolution rates were calculated from measured B concentrations in...

W. L. Ebert S. W. Tam

1996-01-01

154

A Proposed Framework of Test Administration Methods  

ERIC Educational Resources Information Center

|The widespread application of personal computers to educational and psychological testing has substantially increased the number of test administration methodologies available to testing programs. Many of these mediums are referred to by their acronyms, such as CAT, CBT, CCT, and LOFT. The similarities between the acronyms and the methods

Thompson, Nathan A.

2008-01-01

155

Test method evaluation experiments and data  

Microsoft Academic Search

Abstract Understanding,the effectiveness of their production ,tests isa,critical task for IC suppliers. Numerous ,trends suggesting that conventionally applied test methods ,must change to meet future needs will make,the task even more critical ? and difficult ? in the future. This paper presents characterization and ,diagnostic data and ideas aimed ,at helping IC suppliers understand test effectiveness.

Phil Nigh; Anne E. Gattiker

2000-01-01

156

Test Method of Pneumatic Cylinder's life  

Microsoft Academic Search

Pneumatic cylinder is an important element in pneumatic fluid power systems, and its performance determines the system's performance. Efficient and economical production requires highly reliable machines and equipment, so its reliability must be grasped. However, there were no evaluating standard and test methods in ISO standard. The paper presents a method about the reliability test circuit of pneumatic cylinders, which

Ma Jungong; ONEYAMA Naotake

2007-01-01

157

Absorbing Software Testing into the Scrum Method  

NASA Astrophysics Data System (ADS)

In this paper we study, how to absorb software testing into the Scrum method. We conducted the research as an action research during the years 2007-2008 with three iterations. The result showed that testing can and even should be absorbed to the Scrum method. The testing team was merged into the Scrum teams. The teams can now deliver better working software in a shorter time, because testing keeps track of the progress of the development. Also the team spirit is higher, because the Scrum team members are committed to the same goal. The biggest change from test manager’s point of view was the organized Product Owner Team. Test manager don’t have testing team anymore, and in the future all the testing tasks have to be assigned through the Product Backlog.

Tuomikoski, Janne; Tervonen, Ilkka

158

Diffusive crystal dissolution  

Microsoft Academic Search

Crystal dissolution may include three component processes: interface reaction, diffusion and complications due to convection. We report here a theoretical and experimental study of crystal dissolution in silicate melt without convection. A reaction-diffusion equation is developed and numerically solved. The results show that during non-convective crystal dissolution in silicate melt, the interface melt composition reaches a constant or stationary “saturation”

Youxue Zhang; David Walker; Charles E. Lesher

1989-01-01

159

Modeling diffusive dissolution in silicate melts  

NASA Astrophysics Data System (ADS)

Here empirical models for calculating self-diffusion coefficients and diffusion matrices are combined with MELTS, a thermodynamic model for silicate minerals and melts, to estimate diffusive dissolution rates, interface melt compositions and melt diffusivities. Simulations of olivine dissolution experiments in basalt show that the overall model is capable of accurately reproducing diffusive dissolution rates, and the resulting diffusion profiles, over a range of pressures and temperatures. However, the overall model is less successful at reproducing olivine dissolution in andesite, diopside dissolution in either basalt or andesite, or anorthite dissolution in picrite. Yet, even for these systems the predicted dissolution rates are generally within about a factor of two of the measured ones. Comparisons between simulations and experiments suggest that errors in the self-diffusion and thermodynamic models are responsible for the differences, and show that dissolution experiments could be a powerful way of testing and calibrating these and similar models. The overall model will also be a useful tool for designing future experiments, and for identifying the parameters that control diffusive dissolution (and crystallization) in silicate melts under a wide range of conditions.

Alexander, Conel M. O.'D.

160

The biogenic content of process streams from mechanical-biological treatment plants producing solid recovered fuel. Do the manual sorting and selective dissolution determination methods correlate?  

PubMed

The carbon emissions trading market has created a need for standard methods for the determination of biogenic content (chi(B)) in solid recovered fuels (SRF). We compare the manual sorting (MSM) and selective dissolution methods (SDM), as amended by recent research, for a range of process streams from a mechanical-biological treatment (MBT) plant. The two methods provide statistically different biogenic content values, as expressed on a dry mass basis, uncorrected for ash content. However, they correlate well (r(2)>0.9) and the relative difference between them was <5% for chi(B) between 21% (w)/w(d) and 72% (w)/w(d) (uncorrected for ash content). This range includes the average SRF biogenic content of ca. 68% (w)/w(d). Methodological improvements are discussed in light of recent studies. The repeatability of the SDM is characterised by relative standard deviations on triplicates of <2.5% for the studied population. PMID:20116991

Séverin, Mélanie; Velis, Costas A; Longhurst, Phil J; Pollard, Simon J T

2010-02-08

161

Rapid Method of Microbial Susceptibility Testing  

PubMed Central

A rapid method of microbial susceptibility testing is described. Bacterial growth is measured by determining the incorporation of 14C-tryptophan into cellular protein in the presence of antimicrobial drugs.

McClatchy, J. Kenneth

1970-01-01

162

In Silico Toxicology - Non-Testing Methods  

PubMed Central

In silico toxicology in its broadest sense means “anything that we can do with a computer in toxicology.” Many different types of in silico methods have been developed to characterize and predict toxic outcomes in humans and environment. The term non-testing methods denote grouping approaches, structure–activity relationship, and expert systems. These methods are already used for regulatory purposes and it is anticipated that their role will be much more prominent in the near future. This Perspective will delineate the basic principles of non-testing methods and evaluate their role in current and future risk assessment of chemical compounds.

Raunio, Hannu

2011-01-01

163

Test methods for environment-assisted cracking  

NASA Astrophysics Data System (ADS)

The test methods for assessing environment assisted cracking of metals in aqueous solution are described. The advantages and disadvantages are examined and the interrelationship between results from different test methods is discussed. The source of differences in susceptibility to cracking occasionally observed from the varied mechanical test methods arises often from the variation between environmental parameters in the different test conditions and the lack of adequate specification, monitoring, and control of environmental variables. Time is also a significant factor when comparing results from short term tests with long exposure tests. In addition to these factors, the intrinsic difference in the important mechanical variables, such as strain rate, associated with the various mechanical tests methods can change the apparent sensitivity of the material to stress corrosion cracking. The increasing economic pressure for more accelerated testing is in conflict with the characteristic time dependence of corrosion processes. Unreliable results may be inevitable in some cases but improved understanding of mechanisms and the development of mechanistically based models of environment assisted cracking which incorporate the key mechanical, material, and environmental variables can provide the framework for a more realistic interpretation of short term data.

Turnbull, A.

1992-03-01

164

A novel method for dissolution and stabilization of non-mulberry silk gland protein fibroin using anionic surfactant sodium dodecyl sulfate.  

PubMed

The importance of silk protein has increased because of its potential use as a natural biopolymer for tissue engineering and biomedical applications. In this report we show a novel and ecofriendly method for dissolution of gland silk protein fibroin. Non-mulberry silk fibroin from mature fifth instar larvae of Antheraea mylitta was found to be optimally soluble in 1% (w/v) anionic surfactant sodium dodecyl sulfate (SDS). Regenerated fibroin showed distinct bands of approximately 395 and 197 kDa on electrophoresis in non-reducing and reducing conditions, respectively. Enhanced fibroin dissolution via internalization of hydrophobic amino groups inside a hydrophilic amino acid core in the form of micelles was observed. Prolonged storage stability without gelation of SDS-extracted fibroin was seen. Atomic force microscopy showed micellar aggregation with mean micellar aggregation size of 8 nm. Circular dichroism spectroscopy revealed predominantly helical conformation due to surfactant addition with internal protein conformational changes as revealed by fluorescence spectroscopic studies. PMID:17969177

Mandal, Biman B; Kundu, S C

2008-04-15

165

[Butanol extraction combined with dilute hydrochloric acid dissolution-atomic fluorescence spectrometric method for indirect determination of molybdenum in Chinese herbal medicine].  

PubMed

A method for indirectly determining the molybdenum in Chinese herbal medicine by butanol extraction and dilute hydrochloric acid dissolution was established for atomic fluorescence spectrometry. The molybdoarsenate heteropoly acid, formed in the presence of As(V) and ammonium molybdate in 0.3 mol x L(-1) sulphuric acid medium, was separated and enriched in the organic solvent, then the evaporation of organic reagent was implemented and the left residue was dissolved in dilute hydrochloric acid in which the arsenic content was determined on behalf of molybdenum. In the optimum experimental conditions, molybdenum content in 0-15 microg x L(-1) range depicts a good linear relationship, the detection limit and relative standard deviation of 0.44 microg x L(-1) and 1.1% were obtained, respectively. Spiked Chinese herbal medicine samples were determined with the proposed method, and recoveries of 95.6%-101.3% were achieved. PMID:23427555

Lu, Jian-Ping; Geng, Guo-Xing; Tang, Yan-Kui; Lu, Zhi-Yong

2012-12-01

166

ASTM Validates Air Pollution Test Methods  

ERIC Educational Resources Information Center

|The American Society for Testing and Materials (ASTM) has validated six basic methods for measuring pollutants in ambient air as the first part of its Project Threshold. Aim of the project is to establish nationwide consistency in measuring pollutants; determining precision, accuracy and reproducibility of 35 standard measuring methods. (BL)|

Chemical and Engineering News, 1973

1973-01-01

167

Direct contact dissolution therapy.  

PubMed

Direct contact dissolution using MTBE is a safe, effective treatment for many patients with cholesterol gallstones when performed by clinicians experienced with this technique. This may be the treatment of choice for many patients at high risk for general anaesthesia or surgery. Cholecystostomy using local anaesthesia with subsequent stone extraction is an alternative requiring prolonged catheter drainage, and is associated with some risk and discomfort (Hawkyard et al, 1990). Most experts concur that laparoscopic cholecystectomy cannot be performed safely and comfortably without general anaesthesia under most circumstances. A second small population of patients are inordinately apprehensive about general anaesthesia or surgical removal of their gallbladder and refuse standard therapy in spite of recurrent biliary symptoms. Although direct contact dissolution is generally well tolerated, it may require several days of paramedical attention with medical supervision. This procedure will be most efficiently, effectively and comfortably performed by an experienced team and is, therefore, probably best provided by referral centres with physicians sufficiently interested in the treatment of biliary tract stone disease to develop expertise with this method. PMID:1486211

Thistle, J L

1992-11-01

168

Dissolution rates of DWPF glasses from long-term PCT  

SciTech Connect

We have characterized the corrosion behavior of several Defense Waste Processing Facility (DWPF) reference waste glasses by conducting static dissolution tests with crushed glasses. Glass dissolution rates were calculated from measured B concentrations in tests conducted for up to five years. The dissolution rates of all glasses increased significantly after certain alteration phases precipitated. Calculation of the dissolution rates was complicated by the decrease in the available surface area as the glass dissolves. We took the loss of surface area into account by modeling the particles to be spheres, then extracting from the short-term test results the dissolution rate corresponding to a linear decrease in the radius of spherical particles. The measured extent of dissolution in tests conducted for longer times was less than predicted with this linear dissolution model. This indicates that advanced stages of corrosion are affected by another process besides dissolution, which we believe to be associated with a decrease in the precipitation rate of the alteration phases. These results show that the dissolution rate measured soon after the formation of certain alteration phases provides an upper limit for the long-term dissolution rate, and can be used to determine a bounding value for the source term for radionuclide release from waste glasses. The long-term dissolution rates measured in tests at 20,000 per m at 90 {degrees}C in tuff groundwater at pH values near 12 for the Environmental Assessment glass and glasses made with SRL 131 and SRL 202 frits, respectively.

Ebert, W.L.; Tam, S.W.

1996-12-31

169

A Test Generation Method Using a Compacted Test Table and a Test Generation Method Using a Compacted Test Plan Table for RTL Data Path Circuits  

Microsoft Academic Search

This paper proposes a test generation method using a compacted test table and a test generation method using a compacted test plan table for RTL data path circuits with DFT where hierarchical test generations are applicable. Moreover, a heuristic algorithm for a compacted test plan table generation is proposed. The proposed methods could shorten test lengths for some RTL data

Toshinori Hosokawa; Hiroshi Date; Michiaki Muraoka

2002-01-01

170

Chalcopyrite dissolution rate laws  

Microsoft Academic Search

Meta-analysis of 173 rate measurements from 21 publications was used to develop rate laws for chalcopyrite dissolution under environmentally relevant conditions. Multiple linear regression analysis of 28 data for nonoxidative chalcopyrite dissolution in the presence of O2 and Cl? produced the following rate law:r=10-1.52e-28200\\/RT[H+]1.68Here, r is the rate of chalcopyrite dissolution in units of molm?2s?1 where the surface area is

Bryn E. Kimball; J. Donald Rimstidt; Susan L. Brantley

2010-01-01

171

Factorial interlaboratory tests for microbiological measurement methods  

Microsoft Academic Search

\\u000a Abstract  This paper presents a validation approach for microbiological methods based on a combination of interlaboratory tests and\\u000a factorial experiments. It requires not more than 4 participants but is achieving comparable statistical confidence as in method\\u000a validation studies with 8–12 participants, if properly designed. The approach is illustrated by a comprehensive validation\\u000a of the Arxula adeninivorans yeast estrogen screen (A-YES) assay

Steffen Uhlig; Petra Gowik

2010-01-01

172

On the factors affecting the dissolution of copper in molten lead-free solders and development of a method to assess the soldering parameters  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the various factors that influence the dissolution of copper in molten solder, paying particular attention to important parameters: temperature, solder composition and flow rate. Design\\/methodology\\/approach – To determine the dissolution rate of copper in lead-free solders, a simple and automated technique is developed. This methodology provides repeatable measurements that allow

D. Di Maio; C. P. Hunt

2009-01-01

173

In vitro Dissolution Studies on Solid Dispersions of Mefenamic Acid.  

PubMed

Solid dispersions of mefanamic acid with a water-soluble polymer polyvinyl pyrrolidine and a super disintegrant, primojel were prepared by common solvent and solvent evaporation methods employing methanol as the solvent. The dissolution rate and dissolution efficiency of the prepared solid dispersions were evaluated in comparison to the corresponding pure drug. Solid dispersions of mefenamic acid showed a marked enhancement in dissolution rate and dissolution efficiency. At 1:4 ratio of mefenamic acid-primojel a 2.61 fold increase in the dissolution rate of mefenamic acid was observed with solid dispersion. The solid dispersions in combined carriers gave much higher rates of dissolution than super disintegrants alone. Mefanamic acid-primojel-polyvinyl pyrrolidine (1:3.2:0.8) solid dispersion gave a 4.11 fold increase in the dissolution rate of mefenamic acid. Super disintegrants alone or in combination with polyvinyl pyrrolidine could be used to enhance the dissolution rate of mefenamic acid. PMID:22303074

Rao, K R S Sambasiva; Nagabhushanam, M V; Chowdary, K P R

2011-03-01

174

IMPROVED TEST METHODS FOR ELECTRONIC AIR CLEANERS  

EPA Science Inventory

The objective of this project was to develop a fractional filtration efficiency test protocol for residential electrostatic precipitators (ESPs) that avoids the limitations of the ASHRAE 52.2 method. Specifically, the objectives were to a) determine the change in efficiency that ...

175

Diverter system test tool and method  

Microsoft Academic Search

A method is described for testing a diverter system on an offshore drilling rig of a type having a marine riser assembly extending to a subsea well, the diverter system having a packer element and at least one port located below the packer element for the passage of drilling fluid flowing upward from the marine riser assembly during drilling. The

R. R. Jr. Funderburg; M. E. Kattner; L. J. Milberger; L. D. Slaughter

1989-01-01

176

Test Simulation using Finite Element Method  

Microsoft Academic Search

The dynamic responses of the standard Charpy impact machine are experimentally studied using the relevant data acquisition system, for the purpose of obtaining the impact response. For this reason, the numerical analysis by means of the finite element method has been used for experiment findings. Modelling of the charpy test was performed in order to obtain strain in the striker

M. B. Ali; S. Abdullah; M. Z. Nuawi; A. K. Ariffin

2011-01-01

177

Test of the Polarized Orbital Method: H-.  

National Technical Information Service (NTIS)

The polarized-orbital method and many of the common variations and approximations of this approach are tested in a computation of the binding energy of the negative hydrogen ion H(-). It is found that if a trial wave function for H(-) is constructed from ...

R. S. Oberoi J. Callaway

1969-01-01

178

Method for non-destructive testing  

DOEpatents

Non-destructive testing method may include providing a source material that emits positrons in response to bombardment of the source material with photons. The source material is exposed to photons. The source material is positioned adjacent the specimen, the specimen being exposed to at least some of the positrons emitted by the source material. Annihilation gamma rays emitted by the specimen are detected.

Akers, Douglas W. (Idaho Falls, ID)

2011-08-30

179

Equated Pooled Booklet Method in DIF Testing  

ERIC Educational Resources Information Center

|Differential item functioning (DIF) analysis is an important step in the data analysis of large-scale testing programs. Nowadays, many such programs endorse matrix sampling designs to reduce the load on examinees, such as the balanced incomplete block (BIB) design. These designs pose challenges to the traditional DIF analysis methods. For…

Cheng, Ying; Chen, Peihua; Qian, Jiahe; Chang, Hua-Hua

2013-01-01

180

Testing alleged mediumship: methods and results.  

PubMed

Mediums claim to be able to communicate with the deceased. Such claims attract a considerable amount of public interest and, if valid, have important implications for many areas of psychology. For over 100 years, researchers have tested alleged mediums. This work has obtained mixed results and provoked a considerable amount of methodological debate. This paper reviews the key issues in this debate, describes how the authors devised a method of testing that aimed to prevent the many problems that have hindered past research, and how they then used this method to test several professional mediums. The results of this work did not support the existence of genuine mediumistic ability. Competing interpretations of these results are discussed, along with ways in which the methodology presented in the paper could be used to assess conceptually similar, but non-paranormal, claims made in clinical, occupational and forensic contexts. PMID:15969829

O'keeffe, Ciarán; Wiseman, Richard

2005-05-01

181

Nonequilibrium thermodynamical model for spent fuel dissolution rate  

SciTech Connect

A non-equilibrium thermodynamic model is developed for the dissolution response of uranium oxide spent fuels waste forms. The objective is to derive function forms for the dissolution rate that are consistent with quasi-static, irreversible thermodynamic processes. These function forms contain thermodynamic chemical potentials of both the solid (spent fuels) and the solution (water chemistries) along with a set of coefficients and parameters that can be evaluated by numerical regression of dissolution test data. Currently, detailed knowledge is not available for the atomic (mechanistic) steps and the sequence of chemical/electro-chemical reaction steps to describe the dissolution process over the range of spent fuel inventory, potential water chemistries, and temperatures. The existing approach is obtaining an experimental data base of dissolution rates for a subset of spent fuels over a range of controlled, aggressive water chemistries and temperatures. With a numerical regression algorithm, these data are used to evaluate empirical parameters in a rate law. The function form of this rate law is a product polynomial of the bulk water chemistry concentrations and temperature. In its present form, this function form does not have an explicit thermodynamic dependence on the uranium oxide waste form. In addition, the use of bulk concentrations in the function form for the regression analysis of the dissolution data would not explicitly account for a dependence from possible surface to bulk concentration differences due to surface adsorption and dipole layers. The following thermodynamic model uses analysis methods and physical concepts taken primarily from classical mechanics, colloidal foundations, thermodynamics, electro-chemistry, and geochemistry.

Stout, R.B.

1995-11-01

182

Preferential dissolution phenomena of nuclear waste materials  

SciTech Connect

Preferential dissolution of polyphase nuclear waste materials in short term leach tests can exaggerate radionuclide release rates when extrapolated to the lifetime of the waste form. Possible preferential leach phenomena are associated with the presence of cracks, intergranular phases and readily soluble phases. The rate of dissolution and the microstructural connectivity of the most soluble phase determine the period over which perferential dissolution is observable. The connectivity of phases is amenable to control during processing by altering the starting green density of the precursor powders.

Clarke, D.R.; Flintoff, J.F.

1983-01-01

183

Test Simulation using Finite Element Method  

NASA Astrophysics Data System (ADS)

The dynamic responses of the standard Charpy impact machine are experimentally studied using the relevant data acquisition system, for the purpose of obtaining the impact response. For this reason, the numerical analysis by means of the finite element method has been used for experiment findings. Modelling of the charpy test was performed in order to obtain strain in the striker during the test. Two types of standard charpy specimens fabricated from different materials, i.e. aluminium 6061 and low carbon steel 1050, were used for the impact simulation testing. The related parameters on between different materials, energy absorbed, strain signal, power spectrum density (PSD) and the relationship between those parameters was finally correlated and discussed.

Ali, M. B.; Abdullah, S.; Nuawi, M. Z.; Ariffin, A. K.

2011-02-01

184

In situ dissolution analysis of EUV resists  

NASA Astrophysics Data System (ADS)

Resist dissolution plays an important role in the optimization of resist materials and processes for next-generation lithographic technologies. In this paper, an in situ analysis of EUV resist dissolution is performed utilizing high-speed atomic force microscopy (HS-AFM). Here, the physical changes in EUV resist films are observed in real-time before, during and after the dissolution process. This concept of observing the actual pattern formation of resists during dissolution brings about new ideas in the understanding of the mechanisms that govern the patterning process. Based on this method, resist film swelling of an acryl-based polymer resist during dissolution was found to be controlled by bounding the PAG-anion to the polymer structure. Moreover, a comparison of analysis results between the HS-AFM and the quartz crystal microbalance is also discussed. A similar trend in the amount of resist swelling was obtained for both methods. However, a large difference between these results was observed. Lastly, recent improvements in the system have allowed the in situ characterization of rinse process after dissolution. Initial results have shown that during the standard rinse process with de-ionized water, there is an occurrence of line size narrowing and afterwards, swelling. These results show the potential of HS-AFM in analyzing not only the dissolution characteristics but also the behavior of resists during the rinse process.

Itani, Toshiro; Santillan, Julius Joseph

2011-03-01

185

Influence of dehydration temperature on water vapor adsorption, dissolution behavior and surface property of ampicillin.  

PubMed

Several specimens of anhydrous ampicillin were prepared by heating the ampicillin trihydrate at 100, 120, 140 and 160 degrees C. The effects of dehydration temperature on water vapor adsorption, dissolution behavior and surface property were investigated. The water vapor adsorption of anhydrous ampicillin was studied at 89% relative humidity, 40 degrees C and the water vapor adsorption rate was found to decrease with increase of dehydration temperature. Dissolution profiles of the various anhydrous specimens were investigated in 96% ethanol at 35 degrees C by the static disk method. The anhydrous form prepared at higher dehydration temperature exhibited faster dissolution rate. Solid phase transformation from the anhydrous form to the trihydrate form occurred during the dissolution test. The rate of phase transformation during the dissolution test decreased with increasing dehydration temperature. Topographic difference of the anhydrous forms prepared at 100 and 160 degrees C was not observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM); however, difference of the microstructural properties was apparently observed by the AFM phase image. Surface free energy study revealed that when ampicillin was dehydrated at high temperature, the sample surface became more hydrophobic resulting in less interaction force with water and slow water sorption rate. From the results, we concluded that the polarity of sample surface induced by dehydration of ampicillin would affect the phase transformation and dissolution behavior. PMID:15620864

Moribe, Kunikazu; Wongmekiat, Arpansiree; Hyakutake, Yuki; Tozuka, Yuichi; Oguchi, Toshio; Yamamoto, Keiji

2004-11-30

186

Continuous plutonium dissolution apparatus  

DOEpatents

This invention is concerned with continuous dissolution of metals such as plutonium. A high normality acid mixture is fed into a boiler vessel, vaporized, and subsequently condensed as a low normality acid mixture. The mixture is then conveyed to a dissolution vessel and contacted with the plutonium metal to dissolve the plutonium in the dissolution vessel, reacting therewith forming plutonium nitrate. The reaction products are then conveyed to the mixing vessel and maintained soluble by the high normality acid, with separation and removal of the desired constituent. (Official Gazette)

Meyer, F.G.; Tesitor, C.N.

1974-02-26

187

Oxygen isotopes in an oolitic ironstone and the determination of goethite ?18O values by selective dissolution of impurities: The 5M NaOH method  

NASA Astrophysics Data System (ADS)

Treatment of iron (III) oxides with hot 5 M NaOH solution can selectively dissolve silicate impurities (KAMPF and SCHWERTMANN, 1982). In the current work 5M NaOH solutions enriched in 18O (+670%.) were employed to determine if this method could be used to purify goethites for ?18O analysis. These experiments suggest that the structural stoichiometric oxygen in well-crystallized goethites does not exchange with hot 5 M NaOH solution. Therefore, this selective dissolution method appears to be isotopically viable. 18O-“normal” 5 M NaOH treatments were applied to goethite-dominated ooids of the Upper Ordovician Neda Fm. ironstone. While not completely removed by successive NaOH treatments, the impurities were incrementally dissolved in constant elemental proportions (within analytical error). Consequently, the ?18O value of the endmember goethite could be determined by material balance calculations. This goethite ?18O value is ?1.0%. for all analyzed samples of Neda Fm. ooids, including those from occurrences about 200 km apart. The spatial uniformity of the oolitic goethite ?18O values suggests uniform conditions of goethite formation. The conditions might have been those of a low latitude continental weathering environment.

Yapp, Crayton J.

1991-09-01

188

Oxygen isotopes in an oolitic ironstone and the determination of goethite. delta. sup 18 O values by selective dissolution of impurities: The 5 M NaOH method  

SciTech Connect

Treatment of iron (III) oxides with hot 5 M NaOH solution can selectively dissolve silicate impurities (Kampf and Schwertmann, 1982). In the current work 5M NaOH solutions enriched in {sup 18}O (+670 {per thousand}) were employed to determine if this method could be used to purify goethites for {delta}{sup 18}O analysis. These experiments suggest that the structural stoichiometric oxygen in well-crystallized goethites does not exchange with hot 5 M NaOH solution. Therefore, this selective dissolution method appears to be isotopically viable. {sup 18}O- normal' 5 M NaOH treatments were applied to goethite-dominated ooids of the Upper Ordovician Neda Fm. ironstone. While not completely removed by successive NaOH treatments, the impurities were incrementally dissolved in constant elemental proportions (within analytical error). Consequently, the {delta}{sup 18}O value of the endmember goethite could be determined by material balance calculations. This goethite {delta}{sup 18} value is {minus}1.0{per thousand} for all analyzed samples of Neda Fm. ooids, including those from occurrences about 200 km apart. The spatial uniformity of the oolitic goethite {delta}{sup 18}O values suggest uniform conditions of goethite formation. The conditions might have been those of a low latitude continental weathering environment.

Yapp, C.J. (Univ. of New Mexico, Albuquerque (United States))

1991-09-01

189

The semismooth Newton method for the solution of reactive transport problems including mineral precipitation-dissolution reactions  

Microsoft Academic Search

The semismooth Newton method was introduced in a paper by Qi and Sun (Math. Program. 58:353–367, 1993) and the subsequent work by Qi (Math. Oper. Res. 18:227–244, 1993). This method became the basis of many solvers for certain classes of nonlinear systems of equations defined by a nonsmooth\\u000a mapping. Here we consider a particular system of equations that arises from

Hannes Buchholzer; Christian Kanzow; Peter Knabner; Serge Kräutle

2011-01-01

190

Dissolution of two-phase microsystems: Gas and liquid microparticle dissolution and dehydration of biomaterials  

NASA Astrophysics Data System (ADS)

A main focus of this research is to develop techniques to study the dissolution process of two-phase microsystems on a single microparticle basis. This dissertation introduces a systematic approach to investigate the formation of microparticles to fulfill the need for rational design of microspheres for a range of applications. This novel method is based on the micropipet manipulation technique and can essentially test any system, where the continuous phase is a liquid and the dispersed phase is practically any phase, a gas (foam), a liquid (emulsion), or a solid (suspension). It is possible to study single microparticle volumes in the picoliter to nanoliter scale, which is on the same size-scale as particles created in bulk suspensions, microsphere processes, and applications. The ability to create, isolate, observe, and manipulate individual gas, liquid or solid microparticles in a well-defined and controlled liquid environment was found to be ideal to study gas microbubbles and microparticles, liquid microdroplets, and the dehydration of dissolved solutes. Subsequently, one can directly measure the dissolution rate and, when a solute is present, calculate its concentration during the dissolution process. Microbubble or microdroplet dissolution in a second phase is driven by two independent factors, a concentration gradient (undersaturation of the dispersed phase in the continuous phase) and a pressure gradient (due to the Laplace-overpressure inside the microparticle created by the surface tension). Experimentally, each of these driving forces can be independently tested. Both the gas microparticle and pure liquid microdroplet dissolution can be predicted by a simple theory based on the diffusion coefficient and solubility limit of the dispersed phase in the continuous phase. The dehydration of a salt ion solution microdroplet results in the nucleation and growth of a crystal, while the dehydration of proteins leads to glassification of the protein. The water remaining in the glassified protein microsphere is on the order of a water monolayer surrounding each protein molecule. Both observation and measurement of dehydration within a single microdroplet is the basis to understanding microparticle formation for use in drug delivery systems and biomolecule preservation.

Duncan, Phillip Brent

191

A polyexponential deconvolution method. Evaluation of the “gastrointestinal bioavailability” and mean in vivo dissolution time of some ibuprofen dosage forms  

Microsoft Academic Search

A new deconvolution algorithm (DCON) suitable for pharmacokinetic applications is presented. It requires that both the impulse and input responses, typically systemic drug levels, be well described by polyexponential equations. DCON has a wider range of applications than an earlier method (DECONV) from which it is derived. A FORTRAN program is provided, making implementation of the technique a simple matter.

William R. Gillespie; Peter Veng-Pedersen

1985-01-01

192

16 CFR 1500.40 - Method of testing toxic substances.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Method of testing toxic substances. 1500.40 Section 1500.40...REGULATIONS § 1500.40 Method of testing toxic substances. The method of testing the toxic substances referred to in §...

2013-01-01

193

Standardization of Formal Methods in Conformance Testing of Communication Protocols  

Microsoft Academic Search

This paper presents the work developed by the joint ISO\\/ITU-T working group on “Formal Methods in Conformance Testing” (FMCT) in order to obtain a future standard. It concerns several areas of conformance testing: terminology, testing concepts, test architecture, specification languages for tests and test generation methods. The influence of FMCT on testing methodology is also analysed and future trends in

Ana R. Cavalli; Jean Philippe Favreau; Marc Phalippou

1996-01-01

194

Classical Nucleation Theory Explains Mineral Growth and Dissolution Within a Mechanistic and Quantitative Framework  

NASA Astrophysics Data System (ADS)

The dissolution and precipitation of silicate minerals exert strong controls on the spatio-temporal evolution of geothermal and faulted subsurface systems. Geochemical principles dictate that these processes must be dependent upon thermodynamic driving force (extent of fluid undersaturation or supersaturation), however this dependence is not well understood. A complete physical picture that explains widely observed variations in dissolution behavior is lacking and some data show ongoing inconsistencies that cannot be explained by the largely-empirical kinetic `laws'. Here we show that the dissolution of silica and silicate minerals can be understood across broad conditions through the same nucleation rate theory that was originally developed for crystal growth. This theory should, in principle, also apply to dissolution but, before now, has never been tested. Methods: Kinetic measurements were conducted at 200°C using quartz sand (Destin, FL) using established flow-through reactor methods for measuring H4SiO4 production rate at steady state. Undersaturated solutions were prepared with and without reagent grade NaCl or CaCl2·2H2O and additions of silicic acid. All solutions had circumneutral pH and calculated pHT,200 = 5.7. Parallel experiments exposed natural (100) surfaces of a euhedral quartz crystal to four experimental conditions that, according to theory, should give distinct dissolution mechanisms. Durations of each treatment were determined from measured rates to calculate reaction time necessary to give equal silica production at 200°C. Thus, etching times ranged from 28 days to four hours. Resulting nanoscale structures were examined under a drop of water using atomic force microscopy. Findings: By generalizing nucleation theory across the potential energy continuum of growth to include dissolution, we present a quantitative and mechanistic model that explains how quartz dissolution processes change with increasing undersaturation from simple step edge retreat, to dislocation and defect-driven pit nucleation. We further show that the origin of the so-called salt effect that was recognized almost 100 years ago arises from increases in surface energy to activate dissolution by two-dimensional nucleation of vacancy islands, to greatly increase site density. This process has not been heretofore recognized as possible for oxide or silicate minerals. Nucleation rate theory also describes the dependence of dissolution kinetics on undersaturation and supersaturation for the dominant aluminosilicates, kaolinite and K-feldspar. In doing so, it resolves discrepancies between data sets reported for kaolinite at 80° and 200°C by revealing the existence of a temperature-activated transition in the dissolution and growth processes. Nucleation theory may be the missing link to unifying mineral growth and dissolution into a mechanistic and quantitative framework across the continuum of driving force.

Dove, P. M.; Han, N.; de Yoreo, J. J.

2005-12-01

195

Comparison of spray freeze drying and the solvent evaporation method for preparing solid dispersions of baicalein with Pluronic F68 to improve dissolution and oral bioavailability.  

PubMed

The objective of this study was to prepare solid dispersions consisting of baicalein and a carrier with a low glass transition/melting point (Pluronic F68) by spray freeze drying (SFD). We compared these powders to those produced from the conventional solvent evaporation method. In the SFD process, a feeding solution was atomized above the surface of liquid nitrogen following lyophilization, which resulted in instantaneously frozen microparticles. However, solid dispersions prepared by the solvent evaporation method formed a sticky layer on the glass flask with crystalline baicalein separated out from the carrier. The powder samples were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), surface area measurement, differential scanning calorimetry, and Fourier transform infrared spectrometry. SEM and PXRD results suggested that the majority of baicalein in the SFD-processed solid dispersion was in the amorphous state, which has a higher specific surface area than pure baicalein. However, the majority of baicalein was recrystallized in the solid dispersion at the same composition prepared by the solvent evaporation method, which showed a similar dissolution rate to the physical mixture. SFD product was physically and chemically stable after being stored at 40 °C with low humidity for 6 months. After enzyme hydrolysis, baicalein in the SFD product displayed a significantly shorter T (max) and higher C (max) than pure baicalein after oral dosing. The relative bioavailability of the SFD product versus pure baicalein determined by comparing the AUC(0-12) was 233%, which demonstrated the significantly improved oral bioavailability of baicalein produced by the SFD technique. PMID:21181514

He, Xiuqiong; Pei, Lixia; Tong, Henry H Y; Zheng, Ying

2010-12-23

196

EXPERIMENTAL DETERMINATION OF UO2(cr) DISSOLUTION KINETICS: EFFECTS OF SOLUTION SATURATION STATE and pH  

SciTech Connect

To evaluate the release of uranium from natural ore deposits, spent nuclear fuel repositories, and REDOX permeable reactive barriers, knowledge of the fundamental reaction kinetics associated with the dissolution of uranium dioxide is necessary. Dissolution of crystalline uranium (IV) dioxide under environmental conditions has been studied for four decades but a cardinal gap in the published literature is the effect of pH and solution saturation state on UO2(cr) dissolution. To resolve these inconsistencies, UO2 dissolution experiments have been conducted under oxic conditions using the single-pass flow-through system. Experiments were conducted as a function of total dissolved carbonate ([CO3-2]T) from 0.001 to 0.1 M; pH from 7.5 to 11.1; ratio of flow-through rate (q) to specific surface area (S), constant ionic strength (I) = 0.1 M, and temperatures (T) from 23 to 60 C utilizing both powder and monolithic specimens. The results show that UO2 dissolution varies as a function of the ratio q/S and temperature. At values of log10 q/S > -7.0, UO2 dissolution becomes invariant with respect to q/S, which can be interpreted as evidence for dissolution at the forward rate of reaction. The data collected in these experiments show the rate of UO2 dissolution increased by an order of magnitude with a 30? increase in temperature. The results also show the overall dissolution rate will increase with an increase in pH and decrease as the dissolved uranium concentration approaches saturation with respect to secondary reaction products. Thus, as the value of the reaction quotient, Q, approaches equilibrium, K, (with respect to a potential secondary phase) the dissolution rate decreases. This decrease in dissolution rate was also observed when comparing measured UO2 dissolution rates from static tests where r = 1.7 ?0.14 ? 10-8 mol m 2 s-1 to the rate for flow-through reactors where r = 3.1 ?1.2 ? 10-7 mol m-2 s-1. Thus, using traditional static test methods can result in an underestimation of the true forward rate of UO2(cr) dissolution. These results illustrate the release of uranium from UO2 in the natural environment will be controlled by pH, solution saturation state, and the concentration of dissolved carbonate.

Pierce, Eric M.; Icenhower, Jonathan P.; Serne, R JEFFREY.; Catalano, Jeffrey G.

2005-09-01

197

Experimental determination of UO2(cr) dissolution kinetics: Effects of solution saturation state and pH  

NASA Astrophysics Data System (ADS)

To evaluate the release of uranium from natural ore deposits, spent nuclear fuel repositories, and REDOX permeable reactive barriers (PRB), knowledge of the fundamental reaction kinetics associated with the dissolution of uranium dioxide is necessary. Dissolution of crystalline uranium (IV) dioxide under environmental conditions has been studied for four decades but a cardinal gap in the published literature is the effect of pH and solution saturation state on UO2(cr) dissolution. To resolve inconsistencies, UO2 dissolution experiments have been conducted under oxic conditions using the single-pass flow-through system. Experiments were conducted as a function of total dissolved carbonate ([CO3-3]) from 0.001 to 0.1 M; pH from 7.5 to 11.1; ratio of flow-through rate (q) to specific surface area (S), constant ionic strength (I) = 0.1 M, and temperatures (T) from 23 to 60 °C utilizing both powder and monolithic specimens. The results show that UO2 dissolution varies as a function of the ratio q/S and temperature. At values of log10 q/S > -7.0, UO2 dissolution becomes invariant with respect to q/S, which can be interpreted as evidence for dissolution at the forward rate of reaction. The data collected in these experiments show the rate of UO2 dissolution increased by an order of magnitude with a 30 °C increase in temperature. The results also show the overall dissolution rate increases with an increase in pH and decreases as the dissolved uranium concentration approaches saturation with respect to secondary reaction products. Thus, as the value of the reaction quotient, Q, approaches equilibrium, K, (with respect to a potential secondary phase) the dissolution rate decreases. This decrease in dissolution rate (r) was also observed when comparing measured UO2 dissolution rates from static tests where r = 1.7 ± 0.14 × 10-8 mol m-2 s-1 to the rate for flow-through reactors where r = 3.1 ± 1.2 × 10-7 mol m-2 s-1. Thus, using traditional static test methods can result in an underestimation of the true forward rate of UO2(cr) dissolution. These results illustrate the importance of pH, solution saturation state, and the concentration of dissolved carbonate on the release of uranium from UO2 in the natural environment.

Pierce, E. M.; Icenhower, J. P.; Serne, R. J.; Catalano, J. G.

2005-10-01

198

Role of Surfactant and pH in Dissolution of Curcumin.  

PubMed

Curcumin is a phytoconstituent with wide range of biological activity. It is poorly soluble in water. In the present study a new dissolution medium was developed, as there is no validated dissolution method available in the literature. The composition of the dissolution medium was selected on the basis of solubility data at 37 degrees . Solubility data revealed that addition of surfactant may be suitable as a dissolution medium. The suitability of dissolution medium (0.5% sodium lauryl sulphate in water) relative to the other dissolution medium was evaluated. The selected dissolution media was used for the evaluation of curcumin tablets. PMID:20336212

Rahman, S M H; Telny, T C; Ravi, T K; Kuppusamy, S

2009-03-01

199

An Accelerated Method for Soldering Testing  

SciTech Connect

An accelerated method for testing die soldering has been developed. High intensity ultrasonic vibrations have been applied to simulate the die casting conditions such as high pressure and high molten metal velocity on the pin. The soldering tendency of steels and coated pins has been examined. The results suggest that in the low carbon steel/Al system, the onset of soldering is 60 times faster with ultrasonic vibration than that without ultrasonic vibration. In the H13/A380 system, the onset of soldering reaction is accelerated to between 30-60 times. Coatings significantly reduce the soldering tendency. For purposes of this study, several commercial coatings from Balzers demonstrated the potential for increasing the service life of core pins between 15 and 180 times.

Han, Qingyou [ORNL; Xu, Hanbing [University of Tennessee, Knoxville (UTK); Ried, Paul [Ried, Engineering; Olson, Paul [Balzers, Inc.

2007-01-01

200

Measurement of Tampon Absorbency; Test Method Evaluation.  

National Technical Information Service (NTIS)

The 'Syngyna' test, developed by the tampon industry to measure tampon absorbency has been evaluated in the FDA Center for Medical Device Analysis. In addition, two other tests were evaluated which were slight modifications of the 'Syngyna' test but which...

D. E. Marlowe R. M. Weigle R. S. Stauffenberg

1981-01-01

201

Crystal growth of calcite from calcium bicarbonate solutions at constant PCO2 and 25??C: a test of a calcite dissolution model  

USGS Publications Warehouse

A highly reproducible seeded growth technique was used to study calcite crystallization from calcium bicarbonate solutions at 25??C and fixed carbon dioxide partial pressures between 0.03 and 0.3 atm. The results are not consistent with empirical crystallization models that have successfully described calcite growth at low PCO2 (< 10-3 atm). Good agreement was found between observed crystallization rates and those calculated from the calcite dissolution rate law and mechanism proposed by Plummer et al. (1978). ?? 1981.

Reddy, M. M.; Plummer, L. N.; Busenberg, E.

1981-01-01

202

Dissolution Study of Active Pharmaceutical Ingredients Using the Flow Through Apparatus Usp 4  

Microsoft Academic Search

The flow through system has been employed for many years in the testing of different dosage forms such as tablets and capsules. The flow through cell is the method of choice for extended release and poorly soluble products. Thanks to the specific powder cell it is possible to characterize a drug substance with respect to its rate of dissolution. The

E. Beyssac; J. Lavigne

203

Effect of particle size on solubility, dissolution rate, and oral bioavailability: evaluation using coenzyme Q10 as naked nanocrystals  

PubMed Central

In this paper work, four naked nanocrystals (size range 80–700 nm) were prepared without any surfactant or polymer using the solvent/nonsolvent method. The effects of particle size on their solubility, dissolution, and oral bioavailability were investigated. Solubility and dissolution testing were performed in three types of dissolution medium, and the studies demonstrated that the equilibrium solubilities of coenzyme Q10 nanocrystals and bulk drugs were not affected by the dissolution media but the kinetic solubilities were. Kinetic solubility curves and changes in particle size distribution were determined and well explained by the proposed solubilization model for the nanocrystals and bulk drugs. The particle size effect on dissolution was clearly influenced by the diffusion coefficients of the various dissolution media, and the dissolution velocity of coenzyme Q10 increased as particle size decreased. The bioavailability of coenzyme Q10 after oral administration in beagle dogs was improved by reducing the particle size. For 700 nm nanocrystals, the AUC0–48 was 4.4-fold greater than that for the coarse suspensions, but a further decrease in particle size from 700 nm to 120 nm did not contribute to improvement in bioavailability until the particle size was reduced to 80 nm, when bioavailability was increased by 7.3-fold.

Sun, Jiao; Wang, Fan; Sui, Yue; She, Zhennan; Zhai, Wenjun; Wang, Chunling; Deng, Yihui

2012-01-01

204

Diverter system test tool and method  

SciTech Connect

A method is described for testing a diverter system on an offshore drilling rig of a type having a marine riser assembly extending to a subsea well, the diverter system having a packer element and at least one port located below the packer element for the passage of drilling fluid flowing upward from the marine riser assembly during drilling. The method consists of connecting a tubular member to the upper end of a packer having an elastomeric expansive seal element; placing the packer in an upper portion of the marine riser assembly below the diverter system and expanding the seal element against the interior of the upper portion; closing the packer element of the diverter system around the tubular member; and finally applying fluid pressure in the space between the packer element of the diverter system and the seal element of the packer to determine if any leakage in the diverter system exists. The patent also describes an offshore drilling rig linked to a subsea well by a marine riser assembly extending upward from the subsea well.

Funderburg, R.R. Jr.; Kattner, M.E.; Milberger, L.J.; Slaughter, L.D.

1989-04-04

205

40 CFR 63.365 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...description of the device; test results collected...and shall approve appropriate test methods and procedures. ...than a gas chromatograph or a flame ionization analyzer, shall...and will specify appropriate test methods and procedures....

2013-07-01

206

TEST METHOD EVALUATIONS AND EMISSIONS TESTING FOR RATING WOOD STOVES  

EPA Science Inventory

The report gives results of a comparison of three sampling methods for wood burning stoves: the EPA Modified Method 5 (MM5), the Oregon Method 7 (OM7), and the ASTM proposed Method P180. It also addresses the effect that emission format (grams per hour, grams per kilogram wood bu...

207

Testing and Training Methods for Skill Qualification Testing (SQT).  

National Technical Information Service (NTIS)

This report presents a classification system for tasks and items in the SQT Written Component (WC) to help one decide whether that is the best means of testing. Ways of eliminating extraneous reading in WC are discussed. A new form of testing is described...

E. E. Miller

1982-01-01

208

Development and Validation of a Test Method for Formaldehyde Emissions.  

National Technical Information Service (NTIS)

The document details the field validation of a test method for the sampling and analysis of formaldehyde emissions from stationary sources. Three potential source methods were evaluated. Field testing of the methods were conducted at two different sites. ...

E. D. Estes W. F. Gutknecht D. L. Hardison G. B. Howe R. K. M. Jayanty

1990-01-01

209

40 CFR Appendix Ix to Part 268 - Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B)  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B...IX Appendix IX to Part 268âExtraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method...

2013-07-01

210

77 FR 1129 - Revisions to Test Methods and Testing Regulations  

Federal Register 2010, 2011, 2012, 2013

...requirements for performance tests for stationary RICE...CO (a) Using ASTM D6522- stationary RICE. emissions. at the inlet and and O2...percent O2, dry basis. 2. 4SRB stationary RICE........ a. Reduce i....

2012-01-09

211

Current methods of testing for human papillomavirus  

Microsoft Academic Search

Human papillomavirus DNA testing is gaining wider acceptance, yet the majority of testing is still undertaken in the research setting using protocols that are unsuitable for clinical diagnostic laboratories. Large-scale clinical human papillomavirus DNA testing is likely to be introduced as an adjunct to cervical cytology, so the cytology laboratory is an appropriate place for it to be undertaken. This

Philip Davies; Janet Kornegay; Thomas Iftner

2001-01-01

212

Intracellular particle dissolution in alveolar macrophages.  

PubMed Central

Aerosol particles deposited in the lungs that are not readily soluble in the epithelial lining fluid will be phagocytized by alveolar macrophages (AM). Inside the phagolysosomal vacuole, the constituents of the plasma allow dissolution of a variety of compounds at a higher rate than dissolution in extracellular lung fluids. Chelator concentration and a pH value of about 5 were found to control intracellular particle dissolution (IPD). Hence, IPD is the initial step of translocation of dissolved material to blood, which is an important lung clearance mechanism for particles retained long term. IPD rates of uniform test particles determined in human, baboon, and canine AM cultures were similar to initial translocation rates determined in lung clearance studies of the same species after inhalation of the same test particles. IPD rate in cultured AM proved to be a sensitive functional parameter of AM, which was used to identify changes in the clearance mechanism of translocation during different exposure conditions.

Kreyling, W G

1992-01-01

213

Dissolution rate enhancement of piroxicam by ordered mixing.  

PubMed

Micronized piroxicam was mixed with lactose, mannitol, sorbitol, maltitol and sodium chloride to produce ordered mixture in a glass vial by manual hand shaking method. The effect of excipients, surfactant, superdisintegrant, drug concentration and carrier particle size on dissolution rate was investigated. Dissolution rate studies of the prepared ordered mixtures revealed that all water soluble excipients increased the dissolution rate of piroxicam when compared to the dissolution rate of piroxicam or its suspension. Ordered mixture formulation PLF4, consisting of lactose as water soluble excipient, SSG (8% w/s) and SLS (1% w/w), released piroxcam at a very fast rate so much so that about 90% of the composition had passed into solution within 2 min. The order of the dissolution rate enhancement for ordered mixtures of various water soluble excipients was: lactose > mannitol > maltitol > sorbitol > sodium chloride. Carrier granules of size 355-710 µm were most effective in increasing the dissolution rate of drug from ordered mixtures. Decreasing the carrier particle size reduced drug dissolution from ordered mixtures. The dissolution rate of ordered mixtures consisting of 1-5% w/w piroxicam was superior to dissolution rate of piroxicam suspension. The dissolution data fitting and the resulting regression parameters indicated Hixson Crowell, cube root law, as the best fit to drug release data of ordered mixtures. PMID:22713937

Saharan, Vikas Anand; Choudhury, Pratim Kumar

2012-07-01

214

Dissolution rate of magnesium hydrate for wet flue gas desulfurization  

Microsoft Academic Search

Dissolution rate of magnesium hydrate for wet flue gas desulfurization was measured by a pH-stat method. It was found that the dissolution rate of magnesium hydrate was controlled by mass transfer. As can be seen from the experimental results, the dissolution rate of magnesium hydrate increases with increasing reaction temperature and stirring speed. Lower pH value is favorable to the

Rui-tang Guo; Wei-guo Pan; Xiao-bo Zhang; Hong-jian Xu; Jian-xing Ren

2011-01-01

215

Calcination/dissolution residue treatment  

SciTech Connect

Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination.

Knight, R.C.; Creed, R.F. [Westinghouse Hanford Co., Richland, WA (United States); Patello, G.K.; Hollenberg, G.W.; Buehler, M.F.; O`Rourke, S.M. [Pacific Northwest Lab., Richland, WA (United States); Visnapuu, A. [Bureau of Mines, Rolla, MO (United States); McLaughlin, D.F. [Westinghouse Science and Technology Center, Pittsburgh, PA (United States)

1994-09-01

216

Dissolution studies with pilot plant and actual INTEC calcines  

SciTech Connect

The dissolution of Idaho Nuclear Technology and Engineering Center (INTEC) pilot plant calcines was examined to determine solubility of calcine matrix components in acidic media. Two representatives pilot plant calcine types were studied: Zirconia calcine and Zirconia/Sodium calcine. Dissolution of these calcines was evaluated using lower initial concentrations of nitric acid than used in previous tests to decrease the [H+] concentration in the final solutions. Lower [H+] concentrations contribute to more favorable TRUEX/SREX solvent extraction flowsheet performance. Dissolution and analytical results were also obtained for radioactive calcines produced using high sodium feeds blended with non-radioactive Al(NO{sub 3}){sub 3} solutions to dilute the sodium concentration and prevent bed agglomeration during the calcination process. Dissolution tests indicated {gt}95 wt.% of the initial calcine mass can be dissolved using the baseline dissolution procedure, with the exception that higher initial nitric acid concentrations are required. The higher initial acid concentration is required for stoichiometric dissolution of the oxides, primarily aluminum oxide. Statistically designed experiments using pilot plant calcine were performed to determine the effect of mixing rate on dissolution efficiency. Mixing rate was determined to provide minimal effects on wt.% dissolution. The acid/calcine ratio and temperature were the predominate variables affecting the wt.% dissolution, a result consistent with previous studies using other similar types of pilot plant calcines.

Herbst, R.S.; Garn, T.G.

1999-04-01

217

Dissolution Studies With Pilot Plant and Actual INTEC Calcines  

SciTech Connect

The dissolution of Idaho Nuclear Technology and Engineering Center (INTEC) pilot plant calcines was examined to determine solubility of calcine matrix components in acidic media. Two representatives pilot plant calcine types were studied: Zirconia calcine and Zirconia/ Sodium calcine. Dissolution of these calcines was evaluated using lower initial concentrations of nitric acid than used in previous tests to decrease the [H+] concentration in the final solutions. Lower [H+] concentrations contribute to more favorable TRUEX/SREX solvent extraction flowsheet performance. Dissolution and analytical results were also obtained for radioactive calcines produced using high sodium feeds blended with non-radioactive A1(NO3)3 solutions to dilute the sodium concentration and prevent bed agglomeration during the calcination process. Dissolution tests indicated >95 wt. % of the initial calcine mass can be dissolved using the baseline dissolution procedure, with the exception that higher initial nitric acid concentrations are required. The higher initial acid concentration is required for stoichiometric dissolution of the oxides, primarily aluminum oxide. Statistically designed experiments using pilot plant calcine were performed to determine the effect of mixing rate on dissolution efficiency. Mixing rate was determined to provide minimal effects on wt. % dissolution. The acid/calcine ratio and temperature were the predominate variables affecting the wt. % dissolution, a result consistent with previous studies using other similar types of pilot plant calcines.

Herbst, Ronald Scott; Garn, Troy Gerry

1999-04-01

218

Comparison of threshold galling results from two testing methods  

Microsoft Academic Search

In this investigation, threshold galling tests were performed on several types of stainless steel using area contact and line contact testing procedures. The area contact test method employed was the ASTM standard G98, button-on-block test. In this test method, the end of a cylindrical button is placed in contact with a flat block at a desired contact pressure. The button

Scott R Hummel; Benjamin Partlow

2004-01-01

219

Electrochemical Dissolution of Pentlandite Minerals,  

National Technical Information Service (NTIS)

The dissolution behavior of pentlandite-type minerals was studied by using synthetic iron-nickel and cobalt pentlandites. From conventional direct current experiments, it was found that temperature and oxidation potential affect dissolution behavior. The ...

J. Aromaa

1988-01-01

220

Plutonium oxide dissolution  

SciTech Connect

Several processing options for dissolving plutonium oxide (PuO[sub 2]) from high-fired materials have been studied. The scoping studies performed on these options were focused on PuO[sub 2] typically generated by burning plutonium metal and PuO[sub 2] produced during incineration of alpha contaminated waste. At least two processing options remain applicable for dissolving high-fired PuO[sub 2] in canyon dissolvers. The options involve solid solution formation of PuO[sub 2] With uranium oxide (UO[sub 2]) and alloying incinerator ash with aluminum. An oxidative dissolution process involving nitric acid solutions containing a strong oxidizing agent, such as cerium (IV), was neither proven nor rejected. This uncertainty was due to difficulty in regenerating cerium (IV) ions during dissolution. However, recent work on silver-catalyzed dissolution of PuO[sub 2] with persulfate has demonstrated that persulfate ions regenerate silver (II). Use of persulfate to regenerate cerium (IV) or bismuth (V) ions during dissolution of PuO[sub 2] materials may warrant further study.

Gray, J.H.

1992-09-30

221

Improved dissolution and anti-inflammatory effect of ibuprofen by solid dispersion.  

PubMed

The purpose of this study was to improve the dissolution rate and anti-inflammatory effect of ibuprofen by a solid dispersion (SD) method. Initial screening was developed based on drug solubility in carriers in the liquid state to select a suitable water-soluble carrier system for the preparation of SDs. The dissolution of ibuprofen in urea was higher than in PEG4000 or mannitol. Thus, urea was selected as the carrier for the preparation of SDs. SDs were characterized in terms of dissolution, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. Solid dispersion-based (SDBT) and conventional (CT) tablets were prepared by the wet granulation method. The anti-inflammatory effect of SDBT was evaluated using the mouse ear edema test with xylene. In vitro release results indicated that the ibuprofen dissolution rate was improved by the SD. SD characterization results suggested that ibuprofen partly precipitates in crystalline and amorphous forms after SD preparation and that ibuprofen and urea do not interact. SDBT displayed more significant anti-inflammatory effects than CT. The dissolution rate and anti-inflammatory effect of ibuprofen were significantly enhanced by the ibuprofen-urea SD. PMID:22573218

Chen, Liyuan; Dang, Qifeng; Liu, Chengsheng; Chen, Jun; Song, Lei; Chen, Xiguang

2012-05-09

222

The effect of additives on lime dissolution rates. Final report  

Microsoft Academic Search

Based on the previous years` studies concerning the efficiency of SOâ removal by spray dryers with high sulfur coal flue gas, the work for year five included investigations of lime dissolution rates at different slaking conditions and with the effect of additives. The prominent additives that have significant effects on lime dissolution rates were tested with the mini pilot spray

Khang

1996-01-01

223

Dissolution-induced preferential flow in a limestone fracture  

Microsoft Academic Search

Flow in a rock fracture is surprisingly sensitive to the evolution of flow paths that develop as a result of dissolution. Net dissolution may either increase or decrease permeability uniformly within the fracture, or may form a preferential flow path through which most of the injected fluid flows, depending on the prevailing ambient mechanical and chemical conditions. A flow-through test

Jishan Liu; Amir Polak; Derek Elsworth; Avrami Grader

2005-01-01

224

Evaluation of the test method activated sludge, respiration inhibition test proposed by the OECD  

SciTech Connect

The test method of activated sludge, respiration inhibition test proposed by the OECD was critically carried out and compared with other test methods. Investigation of test conditions showed that the moderate deviation from the test conditions defined by the OECD Test Guidelines did not have much effect on the result, and some modifications were proposed to improve the method. This method had a poor detection limit compared with the LC50 test with Oryzias latipes and EC50 of the growth inhibition test with Tetrahymena pyriformis. The susceptivity of the method was particularly poor for the chemicals which were highly toxic in the other two tests.

Yoshioka, Y.; Nagase, H.; Ose, Y.; Sato, T.

1986-12-01

225

Towards a universal dissolution medium for carbamazepine.  

PubMed

The aim of this study was to develop a dissolution medium for assessment of various carbamazepine (CBZ) formulations with different strengths. The design of a system inhibiting transformation of the anhydrous CBZ (CBZ A) to the dihydrate form (CBZ D), with minimum surface-active properties and suitable sink was investigated. The effect of pH, different concentrations of sodium lauryl sulphate (SLS), polyvinylpyrrolidone (PVP), and methyl cellulose (MC) on dissolution rate, solubility, dissolution solubility, and polymorphic transformation of CBZ was assessed. Solution-mediated transformation of CBZ A into CBZ D was monitored using optical microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. Results showed that different strengths (100, 200, 400 mg) of the same CBZ tablet formulation exhibited different dissolution patterns, in 1% SLS (USP system). Such differences were reduced in 0.5% SLS solution which provided sufficient sink for up to 200 mg CBZ. It was also shown that solubility of CBZ A could not be detected in the media under study (water, SGF, SIF, and SLS solutions) due to its rapid transformation into CBZ D. The use of 3% PVP solution protected CBZ A from conversion for 75 min, while 0.01% MC completely inhibited the transformation up to 24 h. Therefore, a medium consisting of 0.5% SLS and 0.01% MC was selected. The medium provided: a) protection against transformation of CBZ A to CBZ D, b) increased solubility of CBZ A (204 mg % compared to 128 mg % of CBZ D in 0.5% SLS), c) suitable sink for up to 400 mg CBZ and d) overlapping dissolution profiles of various strengths of the same CBZ formulation. The suggested system may be a step in the way of solving CBZ dissolution problems that forced the USP to specify two similar dissolution tests with two different limits for conventional 200 mg CBZ tablets. PMID:16908426

El-Massik, M A; Abdallah, O Y; Galal, S; Daabis, N A

2006-08-01

226

Use of partial dissolution techniques in geochemical exploration  

USGS Publications Warehouse

Application of partial dissolution techniques to geochemical exploration has advanced from an early empirical approach to an approach based on sound geochemical principles. This advance assures a prominent future position for the use of these techniques in geochemical exploration for concealed mineral deposits. Partial dissolution techniques are classified as single dissolution or sequential multiple dissolution depending on the number of steps taken in the procedure, or as "nonselective" extraction and as "selective" extraction in terms of the relative specificity of the extraction. The choice of dissolution techniques for use in geochemical exploration is dictated by the geology of the area, the type and degree of weathering, and the expected chemical forms of the ore and of the pathfinding elements. Case histories have illustrated many instances where partial dissolution techniques exhibit advantages over conventional methods of chemical analysis used in geochemical exploration. ?? 1984.

Chao, T. T.

1984-01-01

227

Experimental Study of Acoustically Enhanced Multicomponent DNAPL Ganglia Dissolution  

NASA Astrophysics Data System (ADS)

The impact of acoustic pressure waves on multicomponent nonaqueous phase liquid (NAPL) ganglia dissolution in water-saturated columns packed with glass beads was investigated. Laboratory data from dissolution experiments with two and three component NAPL mixtures suggested that acoustic waves significantly enhance ganglia dissolution due to the imposed oscillatory interstitial water velocity. The dissolution enhancement was shown to be directly proportional to the acoustic wave frequency. Furthermore, it was demonstrated that the greatest dissolution enhancement in the presence of acoustic waves is associated with the component of the NAPL mixture having the smallest equilibrium aqueous solubility. Finally, square shaped acoustic waves were shown to lead to greater NAPL dissolution enhancement compared to sinusoidal and triangular acoustic waves. The results of this study suggested that aquifer remediation using acoustic waves is a promising method particularly for aquifers contaminated with NAPLs containing components with very low equilibrium aqueous solubilities.

Vogler, E. T.; Chrysikopoulos, C. V.

2004-12-01

228

Decomposition methods for scheduling semiconductor testing facilities  

Microsoft Academic Search

We present decomposition procedures for scheduling semiconductor testing facilities. These facilities are characterized by the presence of different types of work centers, some of which have sequence-dependent setup times and some parallel identical machines. We exploit the structure of the routings in semiconductor testing to develop tailored decomposition procedures that decompose the shop into a number of work centers that

Irfan M. Ovacik; Reha Uzsoy

1996-01-01

229

A Method of Evaluating Shorthand Dictation Tests.  

ERIC Educational Resources Information Center

In order to determine whether students transcribe the same number of words regardless of the speed of the dictation, dictation tests were administered to students enrolled in beginning Gregg shorthand at the secondary level. Test batteries were administered at three different times throughout the first semester of shorthand instruction. The…

Gallion, Leona M.; Kavan, C. Bruce

230

Multicomponent Analysis of Liquids by Test Methods  

Microsoft Academic Search

Test strips were proposed for the simultaneous determination of the sum of heavy metals, iron(III), copper, zinc, total alkalinity, hardness, chlorides, sulfates, nitrates, nitrites, and fluorides, and composite test strips were proposed for the determination of copper, iron(III), and cobalt. Determination is based on the dependence of the length of colored zones of indicator papers sealed in a polymer film

V. G. Amelin

2002-01-01

231

MI-98-8: Tetracycline Test Method  

Center for Food Safety and Applied Nutrition (CFSAN)

... for Veterinary Medicine has completed the evaluation of the data submitted to support the modification of the Charm II Tetracycline Drug Test ... More results from www.fda.gov/food/guidanceregulation/guidancedocumentsregulatoryinformation

232

PERFORMANCE TESTING OF METHOD 1312-QA SUPPORT FOR RCRA TESTING  

EPA Science Inventory

The question of how to access the risks associated with ground water contamination from soils containing toxic substances is a critical issue for the Agency. A major limitation of using Method 1310 and 1311 for this purpose is the fact that the sanitary landfill codisposal scenar...

233

Economical test methods for developmental neurobehavioral toxicity.  

PubMed Central

The assessment of behavioral changes produced by prenatal or early postnatal exposure to potentially noxious agents requires both the designing of ad hoc tests and the adaptation of tests for adult animals to the characteristics of successive developmental stages. The experience in designing tests is still more limited than in the adaptation of tests, but several tests have already proven their usefulness; some examples are the suckling test, the homing test, and evaluations of dam-pup and pup-pup interactions. Functional observational batteries can exploit the development at specified postnatal ages of several reflexes and responses that are absent at birth in altricial rodent species with a short pregnancy such as the rat and the mouse. In neonates, the assessment of early treatment effects can rely not only on deviations from normal responding but also on changes in the time of appearance of otherwise normal response patterns. The same applies to other end points such as responses to pain and various types of spontaneous motor/exploratory activities, including reactivity to a variety of drug challenges that can provide information on the regulatory systems whose development may be affected by early treatments. In particular, the analysis of ontogenetic dissociations (i.e., differential early treatment effects depending jointly on developmental stage at the time of exposure, age of testing, and response end point) can be of considerable value in the study of treatments' mechanisms of action. Overall, it appears that behavioral teratological assessments can be effectively used both proactively, i.e., in risk assessment prior to any human exposure, and reactively. In the latter case, these assessments could have special value in the face of agents suspected to produce borderline changes in developing humans, whose innocuousness or noxiousness can be difficult to establish in the absence of hard evidence of teratogenicity.

Bignami, G

1996-01-01

234

Colour Testing of Nitrocellulose Propellants by a Spectrophotometric Method.  

National Technical Information Service (NTIS)

The colour test is a test for chemical stability that can be applied to many of the nitrocellulose propellants stabilized with ethyl centralite. A spectrophotometric method has been developed for carrying out this test and for the preparation and checking...

R. M. Kempson

1983-01-01

235

Developing Test Methods to Measure the Potency of Toxoid ...  

Center for Biologics Evaluation and Research (CBER)

... use of similar manufacturing and testing techniques for ... design and use of effective test methods that ... of botulinum toxoid antigens tested, those most ... More results from www.fda.gov/biologicsbloodvaccines/scienceresearch/biologicsresearchareas

236

Dissolution of human brown pigment biliary stones.  

PubMed

The chemical dissolution of human brown pigment stones was studied using various monophasic multicomponent solvents. Among the nine solutions tested for stone powder dissolution capacity, the two most active were retained for further analysis. The solvent containing 26 mM ethylenediaminetetraacetate, 40 mM sodium deoxycholate, 10 mM monoolein and 30% dimethylsulfoxide was efficient for calcium and bilirubin solubilization. The other solvent containing dimethylsulfoxide/methyl tert-butyl ether (70:30) had a high capacity for dissolution of cholesterol and bilirubin. From in vitro stone dissolution experiments, we found that alternating treatment every 2 h with these two mixtures was more effective than using these solvents separately. Within 24 h, 90% of cholesterol, 80% of bilirubin, and 70% of calcium were dissolved. In vivo, we studied the dissolution of human stones surgically implanted in the gallbladder of 6 rabbits. Alternating perfusions with the solvents selected led to complete disappearance of stones within 16 h in 5 out of 6 cases. The residual histological toxicity in the gallbladder wall, 15 days after perfusion, was low and blood parameters did not differ from the normal values. PMID:2514227

Dai, K Y; Montet, J C; Zhao, X M; Amic, J; Montet, A M

1989-11-01

237

Delayed release tablet dissolution related to coating thickness by terahertz pulsed image mapping.  

PubMed

Delayed release dosage forms such as Asacol employ coatings that are engineered to breakdown and release the drug topically at the nominal pH of the lower intestinal tract. Asacol tablets were found to dissolve in an erratic fashion when they are dissolved in buffers below pH 7 which can occur naturally. In this study Terahertz pulsed imaging (TPI) was used to accurately map the coating thickness of a group of Asacol tablets that were subsequently dissolved using the USP method at pH 6.8. The mean dissolution times were found to correlate with the average coating thickness measured over all surfaces. Thickness values for a single randomly selected face did not correlate well with the dissolution results. The speed and ease of TPI mapping may make it an attractive replacement for wet dissolution testing both in product development and eventually for process analysis. PMID:17722005

Spencer, John A; Gao, Zongming; Moore, Terry; Buhse, Lucinda F; Taday, Philip F; Newnham, David A; Shen, Yaochun; Portieri, Alessia; Husain, Ajaz

2008-04-01

238

40 CFR 60.466 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Test methods and procedures. 60.466 Section 60.466 Protection of Environment ENVIRONMENTAL PROTECTION...of Performance for Metal Coil Surface Coating § 60.466 Test methods and procedures. (a) The...

2013-07-01

239

40 CFR 60.133 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...SOURCES--] [Subpart M - Standards of Performance for Secondary Brass and Bronze] [Sec. 60.133 - Test methods and procedures...STATIONARY SOURCES-- Standards of Performance for Secondary Brass and Bronze Sec. 60.133 Test methods and...

2009-07-01

240

40 CFR 60.583 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...Subpart Fff - Standards of Performance for Flexible Vinyl and Urethane] [Sec. 60.583 - Test methods and procedures.] 40...SOURCES-- Standards of Performance for Flexible Vinyl and Urethane Sec. 60.583 Test methods and procedures. (a)...

2009-07-01

241

Investigation of the Potential of the Dissolution Dynamic Nuclear Polarization Method for General Sensitivity Enhancement in Small-Molecule NMR Spectroscopy  

Microsoft Academic Search

.  We report results of applying a commercial implementation of the dissolution dynamic nuclear polarization (DNP) methodology\\u000a developed by K. G. Golman et al. to a range of molecular species in the mass range of 100–400 Da. The molecules are typical\\u000a of those that might be encountered in natural product chemistry or pharmaceutical analysis. Using an experimental protocol\\u000a previously reported, in

I. J. Day; J. C. Mitchell; M. J. Snowden; A. L. Davis

2008-01-01

242

Comparative dissolution performance of internationally available piroxicam products.  

PubMed

Piroxicam is a widely used nonsteroidal antiinflammatory drug available worldwide under various trade names by several manufacturers. Only one brand of piroxicam (Feldene) is currently marketed in the U.S., and the United States Pharmacopeial Convention established an official dissolution requirement for piroxicam in 1985. The purpose of this study was to evaluate and compare the dissolution performance of several internationally available piroxicam products using the United States Pharmacopeia (USP) dissolution test for piroxicam capsules. Of 25 brands of piroxicam capsules evaluated, 72 percent of the brands failed to meet the USP requirement, several by a wide margin. Although there is no specific USP dissolution test for tablets, the test for capsules was applied to five different brands of piroxicam tablets, and 80 percent of the tablet brands tested failed to meet the USP requirement. Although comparative bioavailability studies would be required to establish any definitive relationship between dissolution test performance and bioavailability, the failure of most of these products to meet the USP requirement for dissolution indicates formulation differences that could result in altered bioavailability. The substantial differences in dissolution performance observed among the piroxicam oral dosage forms tested have implications concerning the equivalency and standards of multisource products available on the international market, and should be taken into account by health care providers worldwide. PMID:3349918

Barone, J A; Lordi, N G; Byerly, W G; Colaizzi, J L

1988-01-01

243

Basic Concepts in Modern Methods of Test Equating.  

ERIC Educational Resources Information Center

This paper summarizes some of the basic concepts in test equating. Various types of equating methods, as well as data collection designs, are outlined, with attempts to provide insight into preferred methods and techniques. Test equating describes a group of methods that enable test constructors and users to compare scores from two different forms…

Woldbeck, Tanya

244

The EFI test method for accelerated growth of water trees  

Microsoft Academic Search

The philosophy behind the development of Rogowski-type test objects and the aging and test procedures used in the Norwegian Electric Power Research Institute (EFI) test method are presented. Some of the results obtained during almost eight years of the use of this method are briefly reviewed. The great advantage of the method is that a model of a cable insulation

H. Faremo; E. Ildstad

1990-01-01

245

A method of mechanical testing of thin-sheet materials  

NASA Astrophysics Data System (ADS)

A method for the mechanical testing of thin-sheet materials is proposed which employs the principle of kinematic pure bending. The theory of the method is examined, and two simple implementations are described along with the testing procedure. The accuracy of the method is evaluated using test results obtained for 0.15-mm-thick sheets of EP578 alloy.

Kalachev, I. B.; Drobyshev, B. A.

246

FORCE-VIBRATION TESTING OF BUILDINGS USING THE LINEAR SHAKER SEISMIC SIMULATION (LSSS) TESTING METHOD  

Microsoft Academic Search

SUMMARY This paper describes the development and numerical verification of a test method to realistically simulate the seismic structural response of full-scale buildings. The result is a new field testing procedure referred to as the linear shaker seismic simulation (LSSS) testing method. This test method uses a linear shaker system in which a mass mounted on the structure is commanded

Eunjong YU; Daniel H. WHANG; Ravi VENUGOPAL; Jonathan P. STEWART

247

Forced vibration testing of buildings using the linear shaker seismic simulation (LSSS) testing method  

Microsoft Academic Search

SUMMARY This paper describes the development and numerical verication of a test method to realistically simulate the seismic structural response of full-scale buildings. The result is a neweld testing procedure referred to as the linear shaker seismic simulation (LSSS) testing method. This test method uses a linear shaker system in which a mass mounted on the structure is commanded a

Eunjong Yu; Daniel H. Whang; Joel P. Conte; Jonathan P. Stewart; John W. Wallace

2005-01-01

248

The method to test Linux software performance  

Microsoft Academic Search

As more and more extensive application of Linux, a lot of Linux software produced for a variety of applications. With more and more applications running on Linux system, for example openoffice, firefox, virtualbox, GCC, etc. the software performance testing based on Linux kernel is becoming important on Linux platform. The kernel of operating system has a great impact on system

Li Yuanyuan; Xiao Peng; Deng Wu

2010-01-01

249

Multiple Testing with Modified Bonferroni Methods.  

ERIC Educational Resources Information Center

|This paper discusses the issue of multiple testing and overall Type I error rates in contexts other than multiple comparisons of means. It demonstrates, using a 5 x 5 correlation matrix, the application of 5 recently developed modified Bonferroni procedures developed by the following authors: (1) Y. Hochberg (1988); (2) B. S. Holland and M. D.…

Li, Jianmin; And Others

250

Direct exposure methods for testing native atmospheres  

Microsoft Academic Search

In vitro studies of adverse cellular effects induced by inhalable substances face a number of problems due to the difficulties in exposing cultured cells of the respiratory tract directly to test atmospheres composed of complex gases and particulate compounds. This paper discusses the characteristics of in vitro work and summarizes the use of different in vitro technologies to determine the

Michaela Aufderheide

2005-01-01

251

Studies on PEM fuel cell noble metal catalyst dissolution  

Microsoft Academic Search

A combination of electrochemical, spectroscopic and gravimetric methods was carried out on Proton Exchange Membrane (PEM) fuel cell electrodes with the focus on platinum and ruthenium catalysts dissolution, and the membrane degradation. In cyclic voltammetry (CV) experiments, the noble metals were found to dissolve in 1M sulfuric acid solution and the dissolution increased exponentially with the upper potential limit (UPL)

Shuang Ma Andersen; Laila Grahl-Madsen; Eivind M. Skou

2011-01-01

252

Analytical review of drug dissolution and release kinetic models  

Microsoft Academic Search

Objectives: Kinetic study of drug dissolution and release is of importance from different points of view including quality control, comparison, bioavailability of drug dosage forms and delivery systems. Thus, in the present work different kinetic models available in many scientific sources are reviewed analytically. Methods: Several equations and laws of dissolution and release were gathered from many sources. The models

253

Static Coefficient Test Method and Apparatus.  

National Technical Information Service (NTIS)

A method and apparatus is described for determining the static coefficient of friction between contacting surfaces of a plurality of bodies. A flexible filament fixedly connected to one of the bodies is alternately and cyclically tensioned and relaxed in ...

C. L. Haehner J. L. Tarpley

1975-01-01

254

In vitro\\/in vivo correlations of dissolution data of carbamazepine immediate release tablets with pharmacokinetic data obtained in healthy volunteers  

Microsoft Academic Search

The aim of the study was to select a dissolution test method for carbamazepine (CBZ) immediate release tablets, giving the best in vitro\\/in vivo correlations (IVIVC) and to determine the potential of this method as an estimate for bioequivalence testing. Four 200 mg CBZ products which are sold on the Dutch market, covering the innovator and three generic products, were

O. A. Lake; M. Olling; D. M. Barends

1999-01-01

255

Handbook of test methods for evaluating chemical deicers  

SciTech Connect

The handbook contains a structured selection of specific test methods for complete characterization of deicing chemicals. Sixty-two specific test methods are defined for the evaluation of chemical deicers in eight principal property performance areas: (1) physicochemical characteristics; (2) deicing performance; (3) compatibility with bare and coated metals; (4) compatibility with metals in concrete; (5) compatibility with concrete and nonmetals; (6) engineering parameters; (7) ecological effects; and (8) health and safety aspects. The 62 specific chemical deicer test methods are composed of 12 primary and 50 supplementary test methods. The primary test methods, which were developed for conducting the more important evaluations, are identified in the report.

Chappelow, C.C.; McElroy, A.D.; Blackburn, R.R.; Darwin, D.; de Noyelles, F.G.

1992-11-01

256

The effects of test preparation methods employed by medical students on standardized admission tests  

Microsoft Academic Search

Purpose of the study. The primary focus of this study was to identify effective test preparation methods and components used by medical students to enhance their test score performance on the Medical College Admission Test (MCAT). Standardized tests such as the Scholastic Assessment Test (SAT) and American College Test (ACT) for college entrance and the MCAT for admission to most

Edna E Jackson-Gray

2000-01-01

257

Current Status of In Vitro Test Methods for Identifying Ocular Corrosives and Severe Irritants: Hen's Egg Test-Chorioallantoic Membrane Test Method. Background Review Document.  

National Technical Information Service (NTIS)

This Background Review Document (BRD) reviews available data and information regarding the validation status of the Hens Egg Test Chorioallantoic Membrane (HET-CAM) test method for identifying ocular corrosives and severe irritants. The test method was re...

2006-01-01

258

Sea Urchin ('Strongylocentrotus purpuratus') Fertilization Test Method.  

National Technical Information Service (NTIS)

The method measures the toxicity of effluents and receiving water to the gametes of a sea urchin, Strongylocentrotus purpuratus, during a 1 h sperm exposure and a subsequent 20 min exposure period following the addition of eggs for measuring the fertilizi...

G. A. Chapman

1993-01-01

259

SEA URCHIN (STRONGYLOCENTROTUS PURPURATUS) FERTILIZATION TEST METHOD  

EPA Science Inventory

This method measures the toxicity of effluents and receiving water to the gametes of a sea urchin, Strongylocentrotus purpuratus, during a 1 h sperm exposure and a subsequent 20 min exposure period following the addition of eggs for measuring the fertilizing capacity of the sperm...

260

Method and apparatus for container leakage testing  

DOEpatents

An apparatus for use in one-hundred percent leak testing of food containers used in conjunction with a tracer gas. The apparatus includes a shell with entrance and exit air locks to create a controlled atmosphere through which a series of containers is conveyed by a conveyor belt. The pressure in the shell is kept lower than the pressure in the containers and the atmosphere is made to flow with the containers so that a tracer gas placed in the packages before sealing them will leak more readily, but the leaked tracer gas will remain associated with the leaking package as it moves through the shell. The leaks are detected with a sniffer probe in fluid communication with a gas chromatograph. The gas chromatograph issues a signal when it detects a leak to an ejector that will eject the leaking container from the conveyor. The system is timed so that the series of containers can move continuously into and out of the shell, past the probe and the ejector, without stopping, yet each package is tested for leaks and removed if leaking.

Kronberg, James W. (Aiken, SC)

1995-01-01

261

Method and apparatus for container leakage testing  

SciTech Connect

This invention is an apparatus for use in 100% leak testing of food containers used in conjunction with a tracer gas. It includes a shell with entrance and exit air locks to create a controlled atmosphere through which a series of containers is conveyed by a conveyor belt. Pressure in the shell is kept lower than that in the containers and the atmosphere is made to flow with the containers so that a tracer gas placed in the packages before sealing them will leak more readily, but the leaked tracer gas will remain associated with the leaking package as it moves through the shell. The leaks are detected with a sniffer probe in fluid communication with a gas chromatograph (GC). The GC issues a signal when it detects a leak to an ejector that eject the leaking container from the conveyor. The system is timed so that the series of containers can move continuously into and out of the shell, past the probe and the ejector, without stopping, yet each package is tested for leaks and removed if leaking.

Kronberg, J.W.

1993-10-18

262

Method and apparatus for container leakage testing  

SciTech Connect

An apparatus is described for use in one-hundred percent leak testing of food containers used in conjunction with a tracer gas. The apparatus includes a shell with entrance and exit air locks to create a controlled atmosphere through which a series of containers is conveyed by a conveyor belt. The pressure in the shell is kept lower than the pressure in the containers and the atmosphere is made to flow with the containers so that a tracer gas placed in the packages before sealing them will leak more readily, but the leaked tracer gas will remain associated with the leaking package as it moves through the shell. The leaks are detected with a sniffer probe in fluid communication with a gas chromatograph. The gas chromatograph issues a signal when it detects a leak to an ejector that will eject the leaking container from the conveyor. The system is timed so that the series of containers can move continuously into and out of the shell, past the probe and the ejector, without stopping, yet each package is tested for leaks and removed if leaking. 3 figs.

Kronberg, J.W.

1995-02-14

263

Evaluations of Parallelism Testing Methods Using ROC Analysis  

Microsoft Academic Search

Parallelism is often a prerequisite in relative potency determination using bioassays. It involves testing the similarity between a pair of dose–response curves of reference standard and the test sample. Parallelism testing methods currently in use include p-value-based significance tests and interval-based equivalence tests. Recently the conceptual and empirical properties of these tests have been assessed and compared by researchers. However,

Harry Yang; Lanju Zhang

2012-01-01

264

Non-destructive testing method and apparatus  

DOEpatents

Non-destructive testing apparatus may comprise a photon source and a source material that emits positrons in response to bombardment of the source material with photons. The source material is positionable adjacent the photon source and a specimen so that when the source material is positioned adjacent the photon source it is exposed to photons produced thereby. When the source material is positioned adjacent the specimen, the specimen is exposed to at least some of the positrons emitted by the source material. A detector system positioned adjacent the specimen detects annihilation gamma rays emitted by the specimen. Another embodiment comprises a neutron source and a source material that emits positrons in response to neutron bombardment.

Akers, Douglas W. (Idaho Falls, ID)

2011-10-04

265

LATEST METHODS OF NON-DESTRUCTIVE TESTING OF RAILWAY VEHICLES  

Microsoft Academic Search

Non-destructive methods are making a fast progress due to extensive scientific treatment and practical applications of new testing techniques. The application of individual techniques requires of their users good knowledge of the relevant theory and a lot of experience. The experience is the main guideline in choosing the right testing technique. The paper focuses on the ultrasonic testing methods developed

V. Jemec; J. Grum

266

Quantitative Constrained Imaging of Dissolution and Precipitation in a Natural Fracture  

NASA Astrophysics Data System (ADS)

Flow-through tests are completed on a natural fracture in novaculite at temperatures of 200C, 800C, 1200C, and 1500C. Measurements of fluid and dissolved mass fluxes, and concurrent X-ray CT imaging are used to constrain the progress of dissolution and its effect on transport properties. An increase in sample temperature results in a transient closure of the fracture to an equilibrium "set", that evolves over approximately 25 h. Successive temperature increases develop sequential closure, the incremental closure decreasing in magnitude with an increase in temperature. The initial differential pressure drop across the fracture increases by two orders of magnitude through the 900 h duration of the test, representing a reduction in hydraulic aperture from 50 to 10 microns. Net dissolution prevails throughout the test. Observed changes in permeability are consistent with the dissolution of contacting stressed asperities; measured solid mass balances match hydraulically measured changes in aperture for a nominal contact area of 15%. Visual identification of dissolution is at the 37 micron resolution of the imaging method, but conforms to the hydraulic and mass balance observations.

Elsworth, D.; Polak, A.; Grader, A. S.; Yasuhara, H.; Halleck, P. M.; Brantley, S. L.

2002-12-01

267

Results of Ocular Dominance Testing Depend on Assessment Method  

PubMed Central

Purpose We developed a near ocular dominance test modeled after the distance hole-in-the card test, and assessed both test-retest reliability of four tests of ocular dominance and agreement between tests. Methods 46 subjects ages 18 to 78 years with visual acuity 20/40 or better in each eye were enrolled from a primary care practice. All subjects had normal eye examinations, with the exception of refractive error, and were examined in their habitual correction. Subjects were tested twice each with the distance hole-in-the-card test, new near hole- in-the-card test, near convergence test, and the Pediatric Eye Disease Investigator Group (PEDIG) fixation preference test. Test-retest reliability and agreement between tests were evaluated with the Kappa statistic. Results There was substantial to almost perfect test-retest reliability for the distance hole-in-the-card test, new near hole-in-the-card test, convergence test, and PEDIG fixation preference test (Kappa, k=0.77, 0.62, 0.84, 0.77, respectively). In contrast, the agreement between the new near hole in the card test and the other three tests – distance hole in the card, near convergence, and PEDIG fixation preference– was moderate to slight (k=0.41, 0.19, 0.11, respectively). Agreement was moderate to fair (k=0.47, 0.32) between the distance hole in the card test and the near convergence test, and between the distance-hole-in-the-card test and the PEDIG fixation preference test. Agreement was fair (k=0.27) between the near convergence test and the PEDIG fixation preference test. Conclusions Although there was excellent test-retest reliability of each ocular dominance test, there was only moderate to slight agreement between tests. Results of ocular dominance tests seem to vary depending on both the testing distance and the specific activity performed as part of the testing procedure.

Rice, Melissa L.; Leske, David A.; Smestad, Christina E.; Holmes, Jonathan M.

2008-01-01

268

Mikrogolf-Ontsluitingsmethode voor Sediment en Grond, Vergeleken met de Konventionele Reflux-Ekstraktiemethode voor de Bepaling van Metalen met Behulp van Atomaire Absorptiespektrometrie (Microwave Dissolution Method for Sediments and Soils, Compared with the Conventional Reflux-Extraction Method for the Determination of Metals by Means of Atomic Absorption Spectrometry).  

National Technical Information Service (NTIS)

A microwave dissolution method with aqua-regia for the determination of metals in sediments and soils is described. A series of elements in solution was subsequently measured by flame or furnace atomic absorption spectrometry or by ICP. Calibration of the...

J. Nieuwenhuize C. H. Poley-Vos A. H. van den Akker W. van Delft

1990-01-01

269

Prediction of dissolution profiles of acetaminophen beads using artificial neural networks.  

PubMed

Immediate release acetaminophen (APAP) beads with 40% drug loading were prepared using the extrusion-spheronization process. Eighteen batches of beads were prepared based on a full factorial design by varying process variables such as extruder type, extruder screw speed, spheronization speed, and spheronization time. An in vitro dissolution test was carried out using the USP 27 Apparatus II (paddle) method. Artificial Neural Network (ANN) models were developed based on the aforementioned process variables and dissolution data. The trained ANN models were used to predict the dissolution profiles of APAP from the beads, which were prepared with various processing conditions. For training the ANN models, process variables were used as inputs, and percent drug released from APAP beads was used as the output. The dissolution data from one out of 18 batches of APAP beads was selected as the validation data set. The dissolution data of other 17 batches were used to train the ANN models using the ANN software (AI Trilogy) with two different training strategies, namely, neural and genetic. The validation results showed that the ANN model trained with the genetic strategy had better predictability than the one trained with the neural strategy. The ANN model trained with the genetic strategy was then used to predict the drug release profiles of two new batches of APAP beads, which were prepared with process variables that were not used during the ANN model training process. However, the process variables used to prepare the two new batches of APAP beads were within the confines of the process variables used to prepare the 18 batches. The actual drug release profile of these two batches of APAP beads was similar to the ones predicted by the trained and validated ANN model, as indicated by the high f2 values. Furthermore, the ANN model trained with genetic strategy was also used to optimize process variables to achieve the desired dissolution profiles. These batches of APAP beads were then actually prepared using the process variables predicted by the trained and validated ANN model. The dissolution results showed that the actual dissolution profiles of the APAP beads prepared from the predicted process variables were similar to the desired dissolution profiles. PMID:16895844

Peng, Yingxu; Geraldrajan, Maria; Chen, Quanmin; Sun, Yichun; Johnson, James R; Shukla, Atul J

2006-01-01

270

Overview of chemical modeling of nuclear waste glass dissolution  

SciTech Connect

Glass dissolution takes place through metal leaching and hydration of the glass surface accompanied by development of alternation layers of varying crystallinity. The reaction which controls the long-term glass dissolution rate appears to be surface layer dissolution. This reaction is reversible because the buildup of dissolved species in solution slows the dissolution rate due to a decreased dissolution affinity. Glass dissolution rates are therefore highly dependent on silica concentrations in solution because silica is the major component of the alteration layer. Chemical modeling of glass dissolution using reaction path computer codes has successfully been applied to short term experimental tests and used to predict long-term repository performance. Current problems and limitations of the models include a poorly defined long-term glass dissolution mechanism, the use of model parameters determined from the same experiments that the model is used to predict, and the lack of sufficient validation of key assumptions in the modeling approach. Work is in progress that addresses these issues. 41 refs., 7 figs., 2 tabs.

Bourcier, W.L.

1991-02-01

271

Successful topical dissolution of cholesterol gallbladder stones using ethyl propionate.  

PubMed

Topical dissolution of cholesterol gallbladder stones using methyl tert-butyl ether (MTBE) is useful in symptomatic patients judged too ill for surgery. Previous studies showed that ethyl propionate (EP), a C5 ester, dissolves cholesterol gallstones rapidly in vitro, but differs from MTBE in being eliminated so rapidly by the liver that blood levels remain undetectable. Our aim was to test EP as a topical dissolution agent for cholesterol gallbladder stones. Five high-risk patients underwent topical dissolution of gallbladder stones by EP. In three patients, the solvent was instilled via a cholecystostomy tube placed previously to treat acute cholecystitis; in two patients, a percutaneous transhepatic catheter was placed in the gallbladder electively. Gallstone dissolution was assessed by chromatography, by gravimetry, and by catheter cholecystography. Total dissolution of gallstones was obtained in four patients after 6-10 hr of lavage; in the fifth patient, partial gallstone dissolution facilitated basketing of the stones. In two patients, cholesterol dissolution was measured and averaged 30 mg/min. Side effects were limited to one episode of transient hypotension and pain at the infusion site; no patient developed somnolence or nausea. Gallstone elimination was associated with relief of symptoms. EP is an acceptable alternative to MTBE for topical dissolution of cholesterol gallbladder stones in high-risk patients. The lower volatility and rapid hepatic extraction of EP suggest that it may be preferable to MTBE in this investigational procedure. PMID:9201095

Hofmann, A F; Amelsberg, A; Esch, O; Schteingart, C D; Lyche, K; Jinich, H; Vansonnenberg, E; D'Agostino, H B

1997-06-01

272

Adolescents' agreement to test for HIV when different testing methods are offered.  

PubMed

Offering rapid HIV testing improves rates of testing in adults, but little is known about whether offering adolescents a choice of testing methods increases rates of testing. The aims of the study were to determine rates of HIV testing in adolescents when different testing methods were offered and explore factors associated with agreement to be tested for HIV. Participants (n= 200, sexually experienced 13-22 year olds) were recruited from an urban adolescent clinic, completed a 99-item theory-based survey and were offered their choice of venipuncture, rapid fingerstick or rapid oral fluid HIV testing. Approximately half (49.5%) agreed to HIV testing. Male gender, parental completion of high school, intention to test for HIV if offered by clinician and higher perceived likelihood of current HIV infection were independently associated with agreement to test. Combining new strategies, such as opt-out testing, with routine testing may be needed to improve rates of adolescent HIV testing. PMID:22581869

Mullins, T K; Braverman, P K; Dorn, L D; Kollar, L M; Kahn, J A

2012-03-01

273

DEVELOPMENT AND VALIDATION OF A TEST METHOD FOR FORMALDEHYDE EMSSION  

EPA Science Inventory

This document details the field validation of a test method for the sampling and analysis of formaldehyde emissions from stationary sources. hree potential source methods were evaluated. ield testing of the methods were conducted at two different sites. t formaldehyde manufacturi...

274

Three-phase method for leak testing of hollow objects  

Microsoft Academic Search

We describe a new technology for testing hollow objects for leaks by the dynamic flow method and consider some variants. We demonstrate the advantages of the developed method in a comparative analysis of the three most widely used methods for leak testing.

A. A. Vidyaev; M. A. Fadeev; A. E. Yurchenko

1995-01-01

275

40 CFR 60.133 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Secondary Brass and Bronze Production Plants § 60.133 Test methods and procedures. (a) In conducting performance tests...

2010-07-01

276

40 CFR 60.133 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Secondary Brass and Bronze Production Plants § 60.133 Test methods and procedures. (a) In conducting performance tests...

2013-07-01

277

40 CFR 60.93 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Hot Mix Asphalt Facilities § 60.93 Test methods and procedures. (a) In conducting the performance tests required in §...

2013-07-01

278

40 CFR 60.166 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Primary Copper Smelters § 60.166 Test methods and procedures. (a) In conducting performance tests required in § 60.8,...

2013-07-01

279

40 CFR 60.374 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...SOURCES--] [Subpart Kk - Standards of Performance for Lead-Acid Battery Manufacturing] [Sec. 60.374 - Test methods...STATIONARY SOURCES-- Standards of Performance for Lead-Acid Battery Manufacturing Sec. 60.374 Test...

2009-07-01

280

Nonsink dissolution rate equations.  

PubMed

In spite of the fact that film theory is based on severe assumptionss, it is shown to be a good working model. The Niebergall-Goyan equation, the Short-Sharkey-Rhodes equation, and the Pothisiri-Carstensen equation-all based on simple film theory-are shown to hold through 80-90% of the dissolutin process for p-hydroxybenzoic acid and sodium chloride, both at values below and above the amount necessary to saturate the dissolution medium. Deviations are attributed to experimental difficulties and to improper definition of monodisperseness rather than to the assumptions made in the theory. PMID:1185531

Patel, M; Carstensen, J T

1975-10-01

281

Dissolution of pancreatic stones.  

PubMed

Chronic calcific pancreatitis (CCP) is the most clear-cut form of chronic pancreatitis. Till date, the common treatment of CCP has been directed toward discontinuation of alcohol consumption if the disease is associated closely with alcohol abuse, relief of pain, enzyme replacement, and the management of some complications like diabetes mellitus, cyst or abscess of the pancreas, malnutrition etc. In 1979, the research group for chronic pancreatitis in Japan proposed the therapeutic policy for this disease as illustrated in Fig. 1. A plausible new treatment is the dissolution of protein precipitates or calcified stones in pancreatic ducts by oral or intravenous administration of drugs. PMID:2219444

Noda, A

282

Hardness methods for testing maize kernels.  

PubMed

Maize is a highly important crop to many countries around the world, through the sale of the maize crop to domestic processors and subsequent production of maize products and also provides a staple food to subsistance farms in undeveloped countries. In many countries, there have been long-term research efforts to develop a suitable hardness method that could assist the maize industry in improving efficiency in processing as well as possibly providing a quality specification for maize growers, which could attract a premium. This paper focuses specifically on hardness and reviews a number of methodologies as well as important biochemical aspects of maize that contribute to maize hardness used internationally. Numerous foods are produced from maize, and hardness has been described as having an impact on food quality. However, the basis of hardness and measurement of hardness are very general and would apply to any use of maize from any country. From the published literature, it would appear that one of the simpler methods used to measure hardness is a grinding step followed by a sieving step, using multiple sieve sizes. This would allow the range in hardness within a sample as well as average particle size and/or coarse/fine ratio to be calculated. Any of these parameters could easily be used as reference values for the development of near-infrared (NIR) spectroscopy calibrations. The development of precise NIR calibrations will provide an excellent tool for breeders, handlers, and processors to deliver specific cultivars in the case of growers and bulk loads in the case of handlers, thereby ensuring the most efficient use of maize by domestic and international processors. This paper also considers previous research describing the biochemical aspects of maize that have been related to maize hardness. Both starch and protein affect hardness, with most research focusing on the storage proteins (zeins). Both the content and composition of the zein fractions affect hardness. Genotypes and growing environment influence the final protein and starch content and, to a lesser extent, composition. However, hardness is a highly heritable trait and, hence, when a desirable level of hardness is finally agreed upon, the breeders will quickly be able to produce material with the hardness levels required by the industry. PMID:19496585

Fox, Glen; Manley, Marena

2009-07-01

283

Dissolution Kinetics of Zirconia Calcine  

SciTech Connect

Liquid radioactive raffinates from nuclear fuel reprocessing at the Idaho National Engineering and Environmental Laboratory were solidified, or calcines, in a fluidized bed reactor at approximately 500 C to form a dry granular material. This calcine has been provisionally stored near-surface in concrete-encased stainless steel bins at the Idaho Nuclear Technology Engineering Center. Research addressing the permanent immobilization of radioactive waste has been ongoing. One option is to separate the radioactive constituents from the calcine, thereby reducing the radioactive waste volume to be ultimately stored at a national nuclear waste repository. Nitric acid dissolution of the calcine is a key front-end unit operation in the separations option. In order to design calcine dissolution equipment, quantification of dissolution reaction rate parameters is required. A pilot-plant-produced, non-radioactive calcine was utilized to study the dissolution kinetics of a zirconia-type calcine. A heterogeneous overall calcine dissolution rate expression has been developed from the dissolution kinetics experimental data. This modeling work indicates that internal diffusion is the predominate controlling mechanism during dissolution of zirconia-type calcine. A shrinking core model with an exponentially decreasing internal diffusion as dissolution progresses fits that data best. However, this simple heterogeneous reaction model is not adequate to completely describe calcine dissolution.

T. A. Batcheller

1999-06-01

284

Status and applications of echinoid (phylum echinodermata) toxicity test methods  

SciTech Connect

The use of echinoderms for toxicity testing has focused primarily on sea urchins and sand dollars (Strongylocentrotus purpuratus, Arbacia punctulata, Lytechinus pictus, and Dendraster excentricus, for example). The status and relative sensitivity of various test methods are described. The most frequently used test methods consist of short-term exposures of sea urchin sperm or embryos; these tests can be easily conducted at all times of the year by using species with complementary spawning cycles or laboratory conditioned populations of a single species. Data from reference toxicant and effluent toxicity tests are summarized. Information on the precision and sensitivity of echinoid test methods are limited and preclude rigorous comparisons with other test methods. The available data indicate that the sensitivity and precision of these methods are comparable to short-term chronic methods for other marine invertebrates and fish. Recent application of the sperm test in toxicity identification evaluations (TIEs) and studies of effluent toxicity decay and sediment toxicity illustrate the versatility of this rapid (10 to 60 min exposure) test method. Embryo tests typically use a 48 to 96 h exposure period and measure the occurrence of embryo malformations. Most recent applications of the embryo test have been for the assessment of sediment elutriate toxicity. Adult echinoderms are not frequently used to assess effluent or receiving water toxicity. Recent studies have had success in using the adult life stage of urchins and sand dollars to assess the effects of contaminated sediment on growth, behavior, and bioaccumulation.

Bay, S.; Burgess, R.; Nacci, D.

1993-01-01

285

Comparison of HEPA filter test methods in corrosive environments  

SciTech Connect

An evaluation of the three HEPA filter test methods in corrosive environments was conducted: the dioctyl phthalate (DOP) method (US Standard Method ANSI N-101.1-1972), the sodium chloride method (British Standard 3928:1969), and the soda-fluorescein or uranine method (French Standard AFNOR STD NFX 44-011). The effects of humidity, temperature and oxides of nitrogen (NO/sub x/) on each method was examined. The experimental design used in the evaluation measured and separated both the effect of each variable and any interaction between variables on the test method. Recommendations for changes in the standard methods to reduce erratic online results are presented.

Murphy, L.P.; Fernandez, S.J.; Motes, B.G.

1980-07-01

286

Solving SOC test scheduling problem using cross-entropy method  

NASA Astrophysics Data System (ADS)

With the increase of the number of IP cores integrated in SOC, the functions of SOC are becoming more complexed. Test time and test cost grow rapidly, therefore it becomes bottleneck of SOC test. Test scheduling is one of the efficient approaches to solve the forenamed question. Cross-entropy method, which is based on probability density function, has been used to solve the SOC test scheduling problem. Experimental results on ITC'02 benchmarks show that the proposed method provides better test time results compared to the Linear-Programming.

Deng, Libao; Qiao, Liyan; Peng, Xiyuan

2010-08-01

287

New methods for corrosion testing of aluminum alloys  

Microsoft Academic Search

This symposium presents papers on a modification of the EXCO test method for exfoliation corrosion susceptibility in 7XXX, 2XXX, and aluminum-lithium alloys; materials evaluation using wet-dry mixed salt-spray tests; a comparison of potentiodynamic polarization tests with wet-dry mixed salt-spray testing of Al-Mg-Si alloy; an accelerated test for determining microbiological-influenced corrosion resistance of aluminum alloys; and corrosion of aluminum in Al

V. S. Agarwala; G. M. Ugiansky

1992-01-01

288

Phase-Field Modeling of Solute Precipitation and Dissolution  

SciTech Connect

A phase-field approach to the dynamics of liquid-solid interfaces that evolve due to precipitation and/or dissolution is presented. For the purpose of illustration and comparison with other methods, phase field simulations were carried out assuming first order reaction (dissolution/precipitation) kinetics. In contrast to solidification processes controlled by a temperature field that is continuous across the solid/liquid interface (with a discontinuous temperature gradient) precipitation/dissolution is controlled by a solute concentration field that is discontinuous at the solid/liquid interface. The sharp-interface asymptotic analysis of the phase-field equations for solidification [Karma and Rappel, Phys. Rev. E57 (1998) 4342] has been modified for precipitation/dissolution processes to demonstrate that the phase-field equations converge to the proper sharp-interface limit. The mathematical model has been validated for a one-dimensional precipitation/dissolution problem by comparison with the analytical solution.

Zhijie Xu; Paul Meakin

2008-07-01

289

Reductive dissolution of arsenic-bearing ferrihydrite  

NASA Astrophysics Data System (ADS)

Ferrihydrites were prepared by coprecipitation (COP) or adsorption (ADS) of arsenate, and the products were characterized using solid-state methods. In addition, the kinetics of reductive dissolution by hydroquinone of these well-characterized materials were quantified. Characterization and magnetism results indicate that the 10 wt% As COP ferrihydrite is less crystalline and possibly has smaller crystallite size than the other ferrihydrites, which all have similar crystallinity and particle size. The results from reductive dissolution experiments show similar reaction rates, reaction mechanism, and activation energy for ferrihydrite precipitated with or without added arsenate. However, a marked decrease in reactivity was observed for 10 wt% As ADS ferrihydrite. The decrease is not attributed to differences in activation energy but rather the preferential blocking of active sites on the ferrihydrite surface. Results demonstrate that arsenic may be released by the reductive dissolution of arsenic-bearing ferrihydrite regardless of whether the arsenic is coprecipitated with or adsorbed onto the ferrihydrite. However, under these reaction conditions, release from materials with adsorbed arsenate greatly exceeds that from materials with coprecipitated arsenate. In fact, a considerable amount of arsenic was released from the 10 wt% ADS ferrihydrite before reductive dissolution was initiated. Therefore, the characterization of arsenate-bearing iron oxide materials to determine the method of arsenate incorporation into structures—perhaps by quantification of Fe-Fe coordination with EXAFS spectroscopy—may lead to improved predictions of the large-scale release of arsenic within aquifer systems under reducing conditions.

Erbs, Jasmine J.; Berquó, Thelma S.; Reinsch, Brian C.; Lowry, Gregory V.; Banerjee, Subir K.; Penn, R. Lee

2010-06-01

290

Qualind: A method for assessing the accuracy of automated tests.  

PubMed

As audiology strives for cost containment, standardization, accuracy of tests, and accountability, greater use of automated tests is likely. Highly skilled audiologists employ quality control factors that contribute to test accuracy, but they are not formally included in test protocols, resulting in a wide range of accuracy, owing to the various skill and experience levels of clinicians. A method that incorporates validated quality indicators may increase accuracy and enhance access to accurate hearing tests. This report describes a quality assessment method that can be applied to any test that (1) requires behavioral or physiologic responses, (2) is associated with factors that correlate with accuracy, and (3) has an available independent measure of the dimension being assessed, including tests of sensory sensitivity, cognitive function, aptitude, academic achievement, and personality. In this report the method is applied to AMTAS, an automated method for diagnostic pure-tone audiometry. PMID:17252960

Margolis, Robert H; Saly, George L; Le, Chap; Laurence, Jessica

2007-01-01

291

Dissolution of nickel hydroxide in ammoniacal aqueous solutions  

NASA Astrophysics Data System (ADS)

The dissolution of nickel hydroxide in ammoniacal solutions was investigated to develop a new recycling process for nickel-metal hydride batteries. The effects of temperature, total ammonia concentration, and pH of the solution were examined in the range of 30 °C to 60 °C, 3.0 to 5.0 M, and 9.0 to 10.7, respectively. All dissolution-time curves showed sigmoidal shapes, which could be approximately expressed by the Johnson-Mehl-Avrami-Yerofeev-Kolmogrov (JMAYK) equation. The hydroxide particles were pitted, and some of them were broken into fragments in the course of the dissolution. An increase in the surface area of the hydroxide particles due to the formation of pits and fragmentation seemed to be the reason for the acceleration of dissolution in the early stage. The surface area of the hydroxide was measured by the Brunauer-Emmett-Teller (BET) method, and the dissolution rate per surface area was determined. The activation energy for the dissolution was obtained as 100±10 kJ mol-1, which confirmed that the dissolution was controlled by chemical reactions at the hydroxide/liquid interface. The dissolution rate was increased by the increase in ammonia concentration, and the highest rate was observed at pH ca. 10.

Miyake, Masao; Maeda, Masafumi

2006-04-01

292

Sodium tetraphenylborate solubility and dissolution rates  

SciTech Connect

The rate of solid sodium tetraphenylborate (NaTPB) dissolution in In-Tank Precipitation salt solutions has been experimentally determined. The data indicates that the dissolution rate of solid NaTPB is a minor contributor the lag time experienced in the 1983 Salt Decontamination Demonstration Test and should not be considered as the rate determining step. Current analytical models for predicting the time to reach the composite lower flammability limit assume that the lag time is not more than 6 hours, and the data supports this assumption (i.e., dissolution by itself requires much less than 6 hours). The data suggests that another step--such as mass transport, the reaction of a benzene precursor or the mixing behavior--is the rate determining factor for benzene release to the vapor space in Tank 48H. In addition, preliminary results from this program show that the degree of agitation employed is not a significant parameter in determining the rate of NaTPB dissolution. As a result of this study, an improved equation for predicting equilibrium tetraphenylborate solubility with respect to temperature and sodium ion concentration has been determined.

Barnes, M.J.; Peterson, R.A.; Swingle, R.F.; Reeves, C.T.

1995-12-31

293

Susceptibility testing of anaerobic bacteria: myth, magic, or method?  

PubMed Central

The demand for susceptibility testing of anaerobes has increased, yet consensus as to procedure and interpretation in this area has not been achieved. While routine testing of anaerobic isolates is not needed, certain isolates in specific clinical settings should be tested. Also, laboratories may monitor their local antibiograms by doing periodic surveillance batch testing. The National Committee for Clinical Laboratory Standards has published a protocol of methods approved for susceptibility testing of anaerobic bacteria. Both agar and broth microdilution are included; however, the broth disk elution method is no longer approved by the National Committee for Clinical Laboratory Standards because of method-related interpretive errors. A number of newer methods are undergoing evaluation and seem promising. Clinicians and microbiologists reviewing susceptibility reports should be aware of sources of variability in the test results. Variables in susceptibility testing of anaerobes include the media and methods used, organisms chosen for testing, breakpoints chosen for interpretation, antibiotic, and determination of endpoint. Clustering of MICs around the breakpoint may lead to significant variability in test results. Adherence of testing laboratories to approved methods and careful descriptions of the method and the breakpoints used for interpretation would facilitate interlaboratory comparisons and allow problems of emerging resistance to be noted. A variety of resistance mechanisms occurs in anaerobic bacteria, including the production of beta-lactamase and other drug-inactivating enzymes, alteration of target proteins, and inability of the drug to penetrate the bacterial wall. Antimicrobial resistance patterns in the United States and abroad are described.

Wexler, H M

1991-01-01

294

Microscopic simulations of fracture dissolution  

NASA Astrophysics Data System (ADS)

Microscopic simulations of fracture dissolution are reported, taking account of the explicit topography of the pore space, the transport of reactants and products, and the chemical kinetics at the solid surfaces. A three-dimensional numerical model has been constructed, in which the fluid velocity field is calculated with an implicit lattice-Boltzmann method, and the transport of dissolved species is modeled by an innovative random walk algorithm that incorporates the chemical kinetics at the solid surfaces. The model contains no free parameters or semi-empirical mass-transfer coefficients. The simulated morphological changes in a complex fracture are compared with recent laboratory experiments [Detwiler et al., 2003] with the same initial topography.

Szymczak, P.; Ladd, A. J. C.

2004-12-01

295

40 CFR 60.316 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Surface Coating of Metal Furniture § 60.316 Test methods and procedures. (a) The reference methods in appendix A to this part except as provided...

2013-07-01

296

Testing of Local Damages by Surface Activation Method.  

National Technical Information Service (NTIS)

Papers on application of radioactivation methods for remote testing and investigation of the processes of surface damage due to wear and corrosion are analysed. Wide possibilities of the method of accelerated charged particle surface activation with a mul...

I. O. Konstantinov A. I. Leonov

1986-01-01

297

40 CFR 60.583 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Flexible Vinyl and Urethane Coating and Printing § 60.583 Test methods and procedures. (a) Methods in appendix A of this part, except as...

2013-07-01

298

An Improved Method for Students' Flame Tests in Qualitative Analysis  

NASA Astrophysics Data System (ADS)

A new method for flame tests to be performed by students is presented. The method involves the use of a hot wire to vaporize the sample,which is subsequently drawn into the flame via the burner air vent.

Bare, William D.; Bradley, Tom; Pulliam, Elizabeth

1998-04-01

299

An Improved Method for Students' Flame Tests in Qualitative Analysis  

Microsoft Academic Search

A new method for flame tests to be performed by students is presented. The method involves the use of a hot wire to vaporize the sample,which is subsequently drawn into the flame via the burner air vent.

William D. Bare; Tom Bradley; Elizabeth Pulliam

1998-01-01

300

Outlier Measures and Norming Methods for Computerized Adaptive Tests.  

ERIC Educational Resources Information Center

Compares four methods that map outlier statistics to a familiarity probability scale (a "P" value). Explored these methods in the context of computerized adaptive test data from a 1995 nationally administered computerized examination for professionals in the medical industry. (SLD)

Bradlow, Eric T.; Weiss, Robert E.

2001-01-01

301

40 CFR 63.786 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Standard Test Methods for Aromatics in Mineral Spirits by Gas Chromatography (incorporation by referenceâsee § 63.14). In determining...ASTM Method E260-91 or 96: Standard Practice for Gas Chromatography [incorporation by referenceâsee §...

2013-07-01

302

HIV Status Awareness, Partnership Dissolution and HIV Transmission in Generalized Epidemics  

PubMed Central

Objectives HIV status aware couples with at least one HIV positive partner are characterized by high separation and divorce rates. This phenomenon is often described as a corollary of couples HIV Testing and Counseling (HTC) that ought to be minimized. In this contribution, we demonstrate the implications of partnership dissolution in serodiscordant couples for the propagation of HIV. Methods We develop a compartmental model to study epidemic outcomes of elevated partnership dissolution rates in serodiscordant couples and parameterize it with estimates from population-based data (Rakai, Uganda). Results Via its effect on partnership dissolution, every percentage point increase in HIV status awareness reduces HIV incidence in monogamous populations by 0.27 percent for women and 0.63 percent for men. These effects are even larger when the assumption of monogamy can be relaxed, but are moderated by other behavior changes (e.g., increased condom use) in HIV status aware serodiscordant partnerships. When these behavior changes are taken into account, each percentage point increase in HIV status awareness reduces HIV incidence by 0.13 and 0.32 percent for women and men, respectively (assuming monogamy). The partnership dissolution effect exists because it decreases the fraction of serodiscordant couples in the population and prolongs the time that individuals spend outside partnerships. Conclusion Our model predicts that elevated partnership dissolution rates in HIV status aware serodiscordant couples reduce the spread of HIV. As a consequence, the full impact of couples HTC for HIV prevention is probably larger than recognized to date. Particularly high partnership dissolution rates in female positive serodiscordant couples contribute to the gender imbalance in HIV infections.

Reniers, Georges; Armbruster, Benjamin

2012-01-01

303

Saltcake Dissolution FY 2000 Status Report  

SciTech Connect

Laboratory tests were completed on the dissolution characteristics of Hanford saltcake waste from single-shell waste tanks 241-TX- 113, 241-BY-102, 241-BY-106, 241-A-101, and 241-S-102 (henceforth referred to as TX-113, BY-102, BY-106, A-101, and S-102, respectively). This work was funded by the Tanks Focus Area (EM-50) under Technical Task Plan Number RL0-8-WT-41, ''PHMC Pretreatment--Saltcake Dissolution''. The tests performed on saltcake from tank TX-113 were similar in scope to those completed in previous years on waste from tanks BY-102, BY-106, B-106, A-101, and S-102 (Herting 1998, 1999). In addition to the ''standard'' dissolution tests, new types of tests were performed this year related to feed stability and radionuclide distribution. The River Protection Project (RPP) is tasked with retrieving waste from double-shell and single-shell tanks to provide feed for vitrification. The RPP organization needs chemical and physical data to evaluate technologies for retrieving the waste. Little significant laboratory testing has been done to evaluate in-tank dissolution parameters for the various types of saltcake wastes that exist in single-shell tanks. A computer modeling program known as the Environmental Simulation Program (ESP), produced by OLI Systems, Inc of Morris Plains, New Jersey, is being used by the RPP organization to predict solubilities during dilution and retrieval of all tank waste types. Data from this task are provided to ESP users to support evaluation, refinement, and validation of the ESP model.

HERTING, D.L.

2000-09-27

304

Disintegration of highly soluble immediate release tablets: a surrogate for dissolution.  

PubMed

The purpose of the work was to investigate correlation between disintegration and dissolution for immediate release tablets containing a high solubility drug and to identify formulations where disintegration test, instead of the dissolution test, may be used as the acceptance criteria based on International Conference on Harmonization Q6A guidelines. A statistical design of experiments was used to study the effect of filler, binder, disintegrating agent, and tablet hardness on the disintegration and dissolution of verapamil hydrochloride tablets. All formulation variables, i.e., filler, binder, and disintegrating agent, were found to influence tablet dissolution and disintegration, with the filler and disintegrating agent exerting the most significant influence. Slower dissolution was observed with increasing disintegration time when either the filler or the disintegrating agent was kept constant. However, no direct corelationship was observed between the disintegration and dissolution across all formulations due to the interactions between different formulation components. Although all tablets containing sodium carboxymethyl cellulose as the disintegrating agent, disintegrated in less than 3 min, half of them failed to meet the US Pharmacopeia 30 dissolution criteria for the verapamil hydrochloride tablets highlighting the dependence of dissolution process on the formulation components other than the disintegrating agent. The results identified only one formulation as suitable for using the disintegration test, instead of the dissolution test, as drug product acceptance criteria and highlight the need for systematic studies before using the disintegration test, instead of the dissolution test as the drug acceptance criteria. PMID:19387843

Gupta, Abhay; Hunt, Robert L; Shah, Rakhi B; Sayeed, Vilayat A; Khan, Mansoor A

2009-04-23

305

40 CFR 60.154 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...to the incinerator during the test run. Sv = Total volume...to the incinerator during the test run. Qmi = Average mass flow...shall be collected in nonporous jars at the beginning of each run...intervals thereafter until the test ends, and â209 F. Method...

2013-07-01

306

49 CFR 230.45 - Method of testing.  

Code of Federal Regulations, 2011 CFR

... Steam Gauges § 230.45 Method of testing. Steam gauges shall be compared with an accurate test gauge or dead weight tester. While under test load at the MAWP of the boiler to which the gauge will be applied, the gauge shall be set to...

2011-10-01

307

49 CFR 230.45 - Method of testing.  

Code of Federal Regulations, 2010 CFR

... Steam Gauges § 230.45 Method of testing. Steam gauges shall be compared with an accurate test gauge or dead weight tester. While under test load at the MAWP of the boiler to which the gauge will be applied, the gauge shall be set to...

2010-10-01

308

49 CFR 230.45 - Method of testing.  

Code of Federal Regulations, 2010 CFR

... Steam Gauges § 230.45 Method of testing. Steam gauges shall be compared with an accurate test gauge or dead weight tester. While under test load at the MAWP of the boiler to which the gauge will be applied, the gauge shall be set to...

2009-10-01

309

49 CFR 230.45 - Method of testing.  

Code of Federal Regulations, 2012 CFR

... Steam Gauges § 230.45 Method of testing. Steam gauges shall be compared with an accurate test gauge or dead weight tester. While under test load at the MAWP of the boiler to which the gauge will be applied, the gauge shall be set to...

2012-10-01

310

A Test Characteristic Curve Linking Method for the Testlet Model  

ERIC Educational Resources Information Center

|When tests are made up of testlets, a testlet-based item response theory (IRT) model may be used to account for local dependence among items from a common testlet. This study presents a new test characteristic curve method to link calibrations based on the Bradlow, Wainer, and Wang (1999) testlet model. Procedures for calculating the test

Li, Yanmei; Bolt, Daniel M.; Fu, Jianbin

2005-01-01

311

40 CFR 60.64 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...and relative accuracy tests required in § 60.8...and procedures and the test methods in appendix...the same basis (either wet or dry), scf/hr...completing each performance test (see § 60.8) as required...CBI on a compact disk, flash drive or...

2013-07-01

312

Method and apparatus for globally-accessible automated testing  

DOEpatents

A method and apparatus for sharing integrated testing services with a plurality of autonomous remote clients is disclosed. In the disclosed method, in response to an access request message, a process controller transmits an access enabling message to the remote client. The access enabling message includes instructions performable by a remote client to generate test equipment commands. A process controller interprets and transforms these commands into automated test instrument suite commands, which are provided to laboratory modules to perform the indicated tests. Test data results are then obtained and transmitted to the remote client.

Layne, Scott P. (Los Angeles, CA); Beugelsdijk, Tony J. (Los Alamos, NM)

1998-01-01

313

A novel method for testing acoustic resonance of HID lamps  

Microsoft Academic Search

This paper presented a novel testing method for identifying acoustic resonance (AR) of HID lamps. It was successfully used in a control loop of a ballast of 250 W metal halide lamps. The line voltage feedforward (LVFF) method was adopted to ensure the testing precision. The experimental results show that the proposed scheme makes the examination of AR simple and

J. Zhou; L. Ma; Z. Qian

1999-01-01

314

The membrane resonance method of non-destructive testing  

Microsoft Academic Search

The physical basis of the membrane resonance method of non-destructive testing has been investigated both theoretically and experimentally. The method involves exciting the structure and monitoring the response at the same point, and can be used to detect the presence of delaminations or disbonds at that location. Its advantage over ultrasonic testing is that no couplant is required between the

P. Cawley; C. Theodorakopoulos

1989-01-01

315

40 CFR Table 3 of Subpart Bbbbbbb... - Test Methods  

Code of Federal Regulations, 2012 CFR

...locations a and the number of traverse points EPA test method 1 or 1A in appendix A to part 60. 2. Determining the velocity and volumetric flow rate EPA test method 2, 2A, 2C, 2D, 2F, or 2G, as appropriate, in appendix A to part 60....

2012-07-01

316

Solubility Limits on Radionuclide Dissolution.  

National Technical Information Service (NTIS)

This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Moun...

J. F. Kerrisk

1984-01-01

317

Dissolution kinetics of quicklime in various organic solvents and solutions.  

PubMed

The rate of the dissolution of quicklime was measured in different organic solvents and solutions of methanol, ethylene glycol, glycerol and sucrose. It was found that the rate of dissolution in methanol, glycerol and sucrose was dramatically reduced compared with that in deionized water. However, little difference was measured in a solution of ethylene glycol compared with aqueous solutions. The presence of chloride ions increases the rate of dissolution in all solvents and solutions, except for ethylene glycol, where a decrease was actually observed. It was also found that the presence of sulphate ions decreases the rate in all organic solvents and solutions tested. PMID:22856289

Potgieter, J H; Gregory, H

2012-06-01

318

40 CFR 60.1300 - What test methods must I use to stack test?  

Code of Federal Regulations, 2013 CFR

...Commenced After June 6, 2001 Stack Testing § 60.1300 What test methods must I use to stack test? (a) Follow table...pollutants. (b) Make sure that stack tests for all the pollutants...the average of the pollutant emission concentrations from the...

2013-07-01

319

40 CFR 62.15245 - What test methods must I use to stack test?  

Code of Federal Regulations, 2013 CFR

...or Before August 30, 1999 Stack Testing § 62.15245 What test methods must I use to stack test? (a) Follow table...pollutants. (b) Make sure that stack tests for all these pollutants...the average of the pollutant emission concentrations from the...

2013-07-01

320

Percutaneous transhepatic dissolution of gallbladder stones.  

PubMed

The method of percutaneous transhepatic dissolution with methyl tert-butyl ether (MTBE) has been used at the Zagreb Clinical Hospital Department of Medicine since 1989. From December 1989 until December 1991, 69 patients, 51 (74%) females and 18 (26%) males, with symptomatic and cholesterol gallbladder stones were hospitalised at the Department. All patients preferred percutaneous transhepatic dissolution to surgical treatment of gallbladder stones. The gallbladder was successfully punctured and the catheter placed into the gallbladder lumen in 63 (91%) patients, whereas complete dissolution was achieved in 59 (85.5%) patients. In 21 (33.9%) of these 59 patients, after completed dissolution computer-processed roentgenograms and ultrasonic scan of the gallbladder revealed residual particles of debris sized up to 2 mm. Six patients in whom puncture, i.e. the placement of the catheter into the lumen was unsuccessful, were electively operated on the following day without any complications. The mean duration of hospitalisation for 63 patients was 4.5 days. PMID:1509785

Salamon, V; Simunic, S; Radanovic, B

1992-07-01

321

A Rigorous Method for Testing Real-Time Reactive Systems  

Microsoft Academic Search

Real-time reactive systems are complex systems to design andverify. Rigorous testing of real- time reactive systems complement the more difficult and expe nsive formal verification process. This paper gives a rigorous method for black-box testing of real- time reactive systems whose design specifications are given in the Timed Reactive Object Model (TROM) formalism. This paper discusses a black-box testing method

Vangalur S. Alagar; Mao Zheng

2001-01-01

322

Test Methods in the Development of Sports Equipment  

Microsoft Academic Search

\\u000a The advancement and diversification of sports is closely linked to the enhancement, new development and increasing testing\\u000a of sports equipment, which can be implemented by using a variety of test methods and procedures. The presentation outlines\\u000a these test methods for specific examples and demonstrates the significance, possibilities and limitations of the development\\u000a of sports equipment. The focus is to show

Stephan Odenwald

323

Environment-sensitive fracture: Evaluation and comparison of test methods  

SciTech Connect

These proceedings collect papers on metal fracture mechanics. Titles include: A Fracture Mechanics Model for Iodine Stress Corrosion Crack Propagation in Zircaloy Tubing; Evaluation of SCC Test Methods for Inconel 600 in Low-temperature Aqueous Solutions; Automated Corrosion Fatigue Crack Growth Testing in Pressurized Water Environments; and use of a constant /Delta//kappa/ test method in the investigation of fatigue crack growth in 288/sup 0/C water environments.

Dean, S.W.; Pugh, E.N.; Ugiansky, G.M

1984-01-01

324

12 CFR 546.4 - Voluntary dissolution.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Voluntary dissolution. 546.4 Section 546.4 Banks...MUTUAL SAVINGS ASSOCIATIONS-MERGER, DISSOLUTION, REORGANIZATION, AND CONVERSION § 546.4 Voluntary dissolution. A Federal savings...

2010-01-01

325

12 CFR 546.4 - Voluntary dissolution.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Voluntary dissolution. 546.4 Section 546.4 Banks...MUTUAL SAVINGS ASSOCIATIONS-MERGER, DISSOLUTION, REORGANIZATION, AND CONVERSION § 546.4 Voluntary dissolution. A Federal savings...

2009-01-01

326

Experimental results of calcine dissolution studies performed during FY-94,95  

SciTech Connect

Calcine dissolution studies were performed in FY-94,95 in order to extend the knowledge of dissolution and to obtain information necessary for scale-up design and operation. Experiments reported in this document were performed with non-radioactive and actual calcines to generate qualitative data regarding: (a) calcine dissolution rates, (b) undissolved solids settling characteristics, (c) undissolved solids heel formation, and (d) chemical treatments for undissolved solids heel dissolution. The goal of this work was to achieve complete calcine dissolution, or to determine conditions that would result in the maximum calcine dissolution. Small scale laboratory experiments (test-tube dissolutions) and a bench scale dissolver set-up were used in the effort. Results from this work show the bulk of the undissolved solids to settle at a rate of >9 inches per second when the baseline dissolution parameters are used. Baseline dissolution parameters were 100 grams of calcine being dissolved in 1 L of 5 M HNO{sub 3} at > 90 C while the solution is being vigorously and constantly mixed. This work also verified that dissolution is most complete when performed with aggressive mixing. Sequential dissolutions performed with non-radioactive and actual calcine indicate that little undissolved solids heel build-up is expected, and this small heel can be further dissolved by increasing the dissolution time or by adding fresh nitric acid.

Brewer, K.N.; Olson, A.L.; Roesener, W.S.; Tonso, J.L.

1997-09-01

327

In vivo dissolution measurement with indium-111 summation peak ratios  

SciTech Connect

Dissolution of (/sup 111/In)labeled tablets was measured in vivo in a totally noninvasive manner by using a modification of the perturbed angular correlation technique known as the summation peak ratio method. This method, which requires the incorporation of only 10-12 microCi into the dosage form, provided reliable dissolution data after oral administration of (/sup 111/In)lactose tablets. These results were supported by in vitro experiments which demonstrated that the dissolution rate as measured by the summation peak ratio method was in close agreement with the dissolution rate of salicylic acid in a (/sup 111/In)salicylic acid tablet. The method has the advantages of using only one detector, thereby avoiding the need for complex coincidence counting systems, requiring less radioactivity, and being potentially applicable to a gamma camera imaging system.

Jay, M.; Woodward, M.A.; Brouwer, K.R.

1985-10-01

328

Draft Guidance on Paroxetine Please note that a Dissolution ...  

Center for Drug Evaluation (CDER)

Text Version... Please note that a Dissolution Methods Database is available to the public at the OGD website at http://www.accessdata.fda.gov/scripts/cder ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

329

Analysis of Accelerated Life Test Data - Part II: Numerical Methods and Test Planning  

Microsoft Academic Search

This is Part II of a three-part series presenting statistical methods for planning and analyzing temperature-accelerated life tests with the Arrhenius model, when all test units are run to failure. These methods are presented so they can be profitably used by individuals with a limited statistical background. In Part I, the Arrhenius model is described and graphical methods for analysis

Wayne Nelosn

1972-01-01

330

A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics  

SciTech Connect

Currently, DOE is conducting pilot CO{sub 2} injection tests to evaluate the concept of geological sequestration. One strategy that potentially enhances CO{sub 2} solubility and reduces the risk of CO{sub 2} leak back to the surface is dissolution of indigenous minerals in the geological formation and precipitation of secondary carbonate phases, which increases the brine pH and immobilizes CO{sub 2}. Clearly, the rates at which these dissolution and precipitation reactions occur directly determine the efficiency of this strategy. However, one of the fundamental problems in modern geochemistry is the persistent two to five orders of magnitude discrepancy between laboratory-measured and field derived feldspar dissolution rates. To date, there is no real guidance as to how to predict silicate reaction rates for use in quantitative models. Current models for assessment of geological carbon sequestration have generally opted to use laboratory rates, in spite of the dearth of such data for compositionally complex systems, and the persistent disconnect between lab and field applications. Therefore, a firm scientific basis for predicting silicate reaction kinetics in CO{sub 2} injected geological formations is urgently needed to assure the reliability of the geochemical models used for the assessments of carbon sequestration strategies. The funded experimental and theoretical study attempts to resolve this outstanding scientific issue by novel experimental design and theoretical interpretation to measure silicate dissolution rates and iron carbonate precipitation rates at conditions pertinent to geological carbon sequestration. In the first year of the project, we have successfully developed a sample preparation method and completed three batch feldspar dissolution experiments at 200 C and 300 bars. The changes of solution chemistry as dissolution experiments progressed were monitored with on-line sampling of the aqueous phase at the constant temperature and pressure. These data allow calculating overall apparent feldspar dissolution rates and secondary mineral precipitation rates as a function of saturation states. State-of-the-art atomic resolution transmission electron microscopy (TEM), scanning electron microscopy, and electron microprobe was used to characterize the reactants (feldspars before experiments). We experimented with different sample preparation methods for TEM study, and found excellent images and chemical resolution with reactants, which shows promise of the technology and establishes the baseline for comparison with products (feldspars after the experiments). Preliminary electron microscopic characterization shows that the reacted feldspars have etch pits and are covered with secondary sheet silicate phases. Reaction-path geochemical modeling is used to interpret the experimental results. We have established the software and database, and are making great progress. Also during the first year, our education goal of graduate student training has been achieved. A Ph. D. student at Indiana University is progressing well in the degree program and has taken geochemical modeling, SEM, and TEM courses, which will facilitate research in the second and third year. A Ph. D. student at University of Minnesota is progressing well in conducting the experiments, and is near graduation. With the success of training of graduate students and excellent experimental data in the first year, we anticipate a more fruitful year in the second year.

Chen Zhu; William E. Seyfried

2005-01-01

331

Plutonium dissolution process  

DOEpatents

A two-step process for dissolving plutonium metal, which two steps can be carried out sequentially or simultaneously. Plutonium metal is exposed to a first mixture containing approximately 1.0M-1.67M sulfamic acid and 0.0025M-0.1M fluoride, the mixture having been heated to a temperature between 45.degree. C. and 70.degree. C. The mixture will dissolve a first portion of the plutonium metal but leave a portion of the plutonium in an oxide residue. Then, a mineral acid and additional fluoride are added to dissolve the residue. Alteratively, nitric acid in a concentration between approximately 0.05M and 0.067M is added to the first mixture to dissolve the residue as it is produced. Hydrogen released during the dissolution process is diluted with nitrogen.

Vest, Michael A. (Oak Park, IL); Fink, Samuel D. (Aiken, SC); Karraker, David G. (Aiken, SC); Moore, Edwin N. (Aiken, SC); Holcomb, H. Perry (North Augusta, SC)

1996-01-01

332

Plutonium dissolution process  

SciTech Connect

A two-step process is described for dissolving plutonium metal, which two steps can be carried out sequentially or simultaneously. Plutonium metal is exposed to a first mixture containing approximately 1.0M--1.67M sulfamic acid and 0.0025M--0.1M fluoride, the mixture having been heated to a temperature between 45 C and 70 C. The mixture will dissolve a first portion of the plutonium metal but leave a portion of the plutonium in an oxide residue. Then, a mineral acid and additional fluoride are added to dissolve the residue. Alteratively, nitric acid in a concentration between approximately 0.05M and 0.067M is added to the first mixture to dissolve the residue as it is produced. Hydrogen released during the dissolution process is diluted with nitrogen. 2 figs.

Vest, M.A.; Fink, S.D.; Karraker, D.G.; Moore, E.N.; Holcomb, H.P.

1996-01-09

333

Robotic dissolution station  

DOEpatents

This invention is comprised of a robotic station for dissolving active metals in acid in an automated fashion. A vessel with cap, containing the active metal is placed onto a shuttle which retracts to a point at which it is directly beneath a cap removing and retaining mechanism. After the cap is removed, a tube carrying an appropriate acid is inserted into the vessel, and the acid is introduced. The structure of the station forms an open hood which is swept of gases generated by the dissolution and the air removed to a remote location for scrubbing. After the reaction is complete, the shuttle extends and the vessel may be removed by a robot arm.

Beugelsdijk, T.J.; Hollen, R.M.; Temer, D.J.; Haggart, R.J.; Erkkila, T.H.

1991-12-31

334

All-cellulose composites by surface selective dissolution of aligned ligno-cellulosic fibres  

Microsoft Academic Search

All-cellulose composites were successfully prepared by a surface selective dissolution method of aligned ligno-cellulosic fibres using lithium chloride\\/N,N-dimethylacetamide as a solvent. The effect of the immersion time of the aligned fibres in the solvent during preparation was investigated. The structure and mechanical properties of the composites were characterized by X-ray diffraction, scanning electron microscopy, and tensile testing. Optimization of the

Nattakan Soykeabkaew; Noriko Arimoto; Takashi Nishino; Ton Peijs

2008-01-01

335

Testing prediction methods: Earthquake clustering versus the Poisson model  

USGS Publications Warehouse

Testing earthquake prediction methods requires statistical techniques that compare observed success to random chance. One technique is to produce simulated earthquake catalogs and measure the relative success of predicting real and simulated earthquakes. The accuracy of these tests depends on the validity of the statistical model used to simulate the earthquakes. This study tests the effect of clustering in the statistical earthquake model on the results. Three simulation models were used to produce significance levels for a VLF earthquake prediction method. As the degree of simulated clustering increases, the statistical significance drops. Hence, the use of a seismicity model with insufficient clustering can lead to overly optimistic results. A successful method must pass the statistical tests with a model that fully replicates the observed clustering. However, a method can be rejected based on tests with a model that contains insufficient clustering. U.S. copyright. Published in 1997 by the American Geophysical Union.

Michael, A. J.

1997-01-01

336

Light water reactor fuel reprocessing: dissolution studies of voloxidized fuel  

Microsoft Academic Search

Voloxidation is a proposed head-end process to remove tritium from irradiated LWR fuel by roasting the fuel in the presence of oxygen. The process oxidizes UOâ to a fine UâOâ powder with high surface area for dissolution. Small-scale tests with irradiated Robinson, Oconee, and Saxton reactor fuels have been made to determine the dissolution behavior of both voloxidized and nonvoloxidized

D. R. Johnson; J. A. Stone

1977-01-01

337

Successful Topical Dissolution of Cholesterol Gallbladder Stones Using Ethyl Propionate  

Microsoft Academic Search

Topical dissolution of cholesterol gallbladderstones using methyl tert-butyl ether (MTBE) is useful insymptomatic patients judged too ill for surgery.Previous studies showed that ethyl propionate (EP), a C5 ester, dissolves cholesterolgallstones rapidly in vitro, but differs from MTBE inbeing eliminated so rapidly by the liver that bloodlevels remain undetectable. Our aim was to test EP as atopical dissolution agent for cholesterol

Alan F. Hofmann; Andree Amelsberg; Oliver Esch; Claudio D. Schteingart; Kip Lyche; Horacio Jinich; Eric Vansonnenberg; Horacio B. D'Agostino

1997-01-01

338

Investigation into the dissolution and direct assay of high-fired plutonium dioxide. [Fusion-melt with potassium pyrosulfate and sodium peroxide  

Microsoft Academic Search

A fusion-melt and dissolution assay method has been developed and tested for the quantitative analysis of high-fired plutonium dioxide. The method employs fusion of the plutonium dioxide at temperatures greater than the melting point of an eutectic mixture of potassium pyrosulfate plus sodium peroxide. The resultant melt is then titrated directly by either controlled potential coulometry or a gravimetric titration,

1976-01-01

339

Test method to measure resistance towards fragmentation by studded tires  

NASA Astrophysics Data System (ADS)

In the Nordic countries most cars are equipped with studded tires during the winter. The studs increase the wear on the road surfaces and a special test method has been developed to measure the aggregates' resistance towards fragmentation by studded tires. The method has proven to correlate very well with the actual wear on the road surfaces. The Nordic countries Sweden, Norway and Finland have agreed to propose this method as a European Standard test method. One reason is to be able to set requirements on aggregates to be used in countries where studded tires are allowed. A cross-testing project regarding this Nordic abrasion test for studded tires was set up in order to determine the repeatability and the reproducibility of the methods to become European Standard.

Viman, L.

1995-01-01

340

Test report for cesium powder and pellets inner container decontamination method determination test  

SciTech Connect

This report documents the decontamination method determination testing that was performed on three cesium powder and pellets inner container test specimens The test specimens were provided by B and W Hanford Company (BVMC). The tests were conducted by the Numatec Hanford Company (NHC), in the 305 Building. Photographic evidence was also provided by NHC. The Test Plan and Test Report were provided by Waste Management Federal Services, Inc., Northwest Operations. Witnesses to testing included a test engineer, a BC project engineer, and a BC Quality Assurance (QA) representative. The Test Plan was modified with the mutual decision of the test engineer, the BWHC project engineer, and the BVMC QA representative. The results of this decision were written in red (permanent type) ink on the official copy of the test procedure, Due to the extent of the changes, a summary of the test results are provided in Section 3.0 of this Test Report. In addition, a copy of the official copy field documentation obtained during testing is included in Appendix A. The original Test Plan (HNF-2945) will be revised to indicate that extensive changes were required in the field during testing, however, the test documentation will stand as is (i.e., it will not be retyped, text shaded, etc.) due to the inclusion of the test parameters and results into this Test Report.

Kelly, D.L.

1998-08-17

341

Investigation of intrinsic dissolution behavior of different carbamazepine samples.  

PubMed

The aim of the present study was to investigate the effect of the variability of commercially available carbamazepine (CBZ) samples on the intrinsic dissolution behavior in order to recommend a strategy to maintain product quality by monitoring the variability of critical parameters of the bulk drug. Extensive physical characterization of nine anhydrous CBZ samples from three different sources and their respective dihydrates showed that the commercial anhydrous CBZ samples exhibited the same polymorphic form, but different morphology and particle size distribution which led to a variation in the kinetics of conversion from anhydrous to the dihydrate CBZ and therefore to variation in the kinetics of solubility. Disc intrinsic dissolution rate (DIDR) tests showed different intrinsic dissolution behavior of the samples, whereby the transition points of anhydrous to dihydrate conversion varied between 15 and 25 min. On the other hand, converting the anhydrous CBZ's to dihydrate eliminated the variation in intrinsic dissolution behavior. Tablets of the different CBZs and Ludipress were prepared by direct compression. The amount of CBZ dissolved after 15 min showed the same rank order as the rank order of the transition points determined by intrinsic dissolution test. Therefore, the intrinsic dissolution test with specific acceptance criteria can be a valuable and simple tool for monitoring, respectively reducing the variability of the CBZ bulk material. PMID:19900519

Sehi?, Selma; Betz, Gabriele; Hadzidedi?, Seherzada; El-Arini, Silvia Kocova; Leuenberger, Hans

2009-11-10

342

Electrochemical evaluation of dissolution characteristics of Al-based sacrificial anodes in seawater  

NASA Astrophysics Data System (ADS)

The surface dissolution characteristics of Al-based sacrificial anodes in seawater have never been expressed numerically except in words such as uniform dissolution, non-uniform dissolution, serious localized dissolution, etc. An electrochemical method was developed in our laboratory to evaluate the above mentioned characteristics quantitatively. The Al anode samples are polarized to -1000 mv (vs. Ag/AgCl reference electrode) in seawater at 25±1°C, and anodic current-time curves are recorded simultaneously. Then the coulometric density was calculated with the aid of a planimeter. By comparing the coulometric densities of these samples, the surface dissolution characteristics of anodes can be evaluated quantitatively.

Zhang, Jinglei; Guo, Gongyu; Sun, Keliang; Hou, Baorong

1988-03-01

343

Change in pore structure and composition of hardened cement paste during the process of dissolution  

SciTech Connect

An understanding about the dissolution phenomena of cement hydrates is important to assess changes in the long-term performance of radioactive waste disposal facilities. To investigate the alteration associated with dissolution, dissolution tests of ordinary Portland cement (OPC) hydrates were performed. Through observation of the samples after leaching, it was confirmed that ettringite precipitation increased as the dissolution of the portlandite and the C-S-H gel progressed. EPMA performed on cross-sections of the solid phase showed a clear difference between the altered and unaltered parts. The boundary between the two parts was termed the portlandite (CH) dissolution front. As the leaching period became longer, the CH dissolution front shifted toward the inner part of the sample. A linear relationship was derived by plotting the distance moved by the CH dissolution front against the square root of the leaching time. This indicated Ca ion movement by diffusion.

Haga, Kazuko; Shibata, Masahito; Hironaga, Michihiko; Tanaka, Satoru; Nagasaki, Shinya

2005-05-01

344

Standardization of fretting fatigue test methods and equipment  

SciTech Connect

Papers contained in this book are grouped under the topics of the fundamental aspects of fretting fatigue testing (conceptual framework and mechanics of contact), methods and equipment for fretting fatigue testing, environmental and surface conditions, and nonconventional materials and test methods. Papers are presented on the problems of fretting fatigue testing, a critical appraisal of testing methods in fretting fatigue, the determination and control of contact pressure distribution in fretting fatigue, and fretting fatigue analysis of strength improvement models with grooving or knurling on a contact surface. Other papers include a critical review of fretting fatigue investigations at the Royal Aerospace Establishment, techniques for the characterization of fretting fatigue damage, improving fretting fatigue strength at elevated temperatures by shot peening in steam turbine steel, the fretting fatigue properties of a blade steel in air and vapor environments, and fretting fatigue of carbon-fiber-reinforced epoxy laminates.

Attia, M.H.; Waterhouse, R.B.

1992-01-01

345

Recommendations for European solar collector test methods (Liquid heating collectors)  

NASA Astrophysics Data System (ADS)

Standardized testing formats, equipment, conditions, and tests defined as part of the solar flat plate collector testing program performed by the Commission of the European Communities are detailed. The work is a product of efforts at 20 laboratories, and alternative methods have been characterized for tailoring tests to particular locations and climatic conditions. The testing methods are intended for collectors using a liquid as the heat transfer medium. Procedures have been defined for examining steady state and transient performance, heat loss, thermal capacity, pressure drop, and anemometry. Instrumentation types and accuracies have been defined, and a standardized format for presentation of results has been developed. The tests are tailored for determining the durability of the flat plate systems under simulated solar radiation conditions.

Derrick, A.; Gillett, W. B.

346

Gallstone dissolution therapy with ursodiol. Patient selection.  

PubMed

Ursodeoxycholic acid (ursodiol) has been shown to be an effective oral agent for dissolution of gallstones that also has a favorable safety profile. In the selection of patients as candidates for this treatment, stone characteristics and the functional status of the gallbladder are the two most important criteria. Small, primarily cholesterol stones (radiolucent on plain film) are the most suitable for oral dissolution therapy. In addition, a functioning gallbladder (as evidenced by visualization on oral cholecystogram) is required to concentrate the ursodiol-enriched bile and effect stone dissolution. Ursodiol should not be used during pregnancy, in women likely to become pregnant, or in severe acute or chronic intrahepatic cholestasis. Acute cholestasis and common bile duct obstruction also preclude this treatment. Screening tests include basic laboratory tests of liver function, sonographic evaluation of the gallbladder and biliary tree, plain film of the abdomen, and oral cholecystogram. Since few patients meet all the selection criteria ideally, the decision to undertake treatment with ursodiol must be based on the entire clinical profile and on the patient's willingness to accept the predicted likelihood of success. PMID:2598766

Fromm, H

1989-12-01

347

Influence of some test parameters on specimen loading determination methods in instrumented Charpy impact tests  

Microsoft Academic Search

This paper is devoted to the analysis of the influence of some test parameters on impact load and specimen displacement measurements in instrumented Charpy impact tests. As impact material behaviour is a multi-parameter problem, design of experiment method is used in order to organise test campaign and to assess the most influence variables. On one side, it is shown that

P Landrein; T Lorriot; L Guillaumat

2001-01-01

348

40 CFR 60.1790 - What test methods must I use to stack test?  

Code of Federal Regulations, 2010 CFR

...methods must I use to stack test? 60.1790 ...STATIONARY SOURCES Emission Guidelines and Compliance...1999 Model Rule-Stack Testing § 60.1790... (b) Make sure that stack tests for all the pollutants...average of the pollutant emission concentrations...

2010-07-01

349

40 CFR 60.1790 - What test methods must I use to stack test?  

Code of Federal Regulations, 2013 CFR

...methods must I use to stack test? 60.1790 ...STATIONARY SOURCES Emission Guidelines and Compliance...1999 Model Rule-Stack Testing § 60.1790... (b) Make sure that stack tests for all the pollutants...average of the pollutant emission concentrations...

2013-07-01

350

Validation of Field Test Methods for Use of Tire Bales.  

National Technical Information Service (NTIS)

This implementation project validates field test methods for checking the conformity of tire bales used in transportation applications. It also provides guidelines for instrumentation of installations involving tire bales. Specific components include fiel...

B. J. Freilich C. Guzman J. G. Zornberg

2012-01-01

351

40 CFR 60.275a - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Steel Plants: Electric Arc Furnaces and Argon-Oxygen Decarburization Vessels Constructed After August 17, 1983 § 60.275a Test methods and procedures. (a)...

2013-07-01

352

40 CFR 63.750 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) National Emission Standards for Aerospace Manufacturing and Rework Facilities...applicable specification(s) for the aerospace vehicle or component being coated...application method test period for similar aerospace vehicles or components. (iii)...

2013-07-01

353

Analytical Test Method Validation Report, February 15, 2010 ...  

Center for Biologics Evaluation and Research (CBER)

... Analytical Test Method Validation Report, February 15, 2010 - Menveo. DATE: 15 February 2010. TO: Willie F. Vann, Ph.D., Chairman. ... More results from www.fda.gov/biologicsbloodvaccines/vaccines/approvedproducts

354

40 CFR 60.46 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...STATIONARY SOURCES Standards of Performance for Fossil-Fuel-Fired Steam Generators § 60.46 Test methods...pairs of samples. (c) When combinations of fossil fuels or fossil fuel and wood residue are fired, the owner or...

2013-07-01

355

Development of a Contact Permeation Test Fixture and Method.  

National Technical Information Service (NTIS)

A new fixture and method were developed to quantify the cumulative permeated mass of contaminants through personal protective equipment (PPE). Most PPE testing consists of liquid contamination of a swatch and detection by vapor collection. However, vapor ...

T. G. D'Onofrio

2013-01-01

356

FDA's Analytical Methods for Testing of Products Believed to ...  

Center for Food Safety and Applied Nutrition (CFSAN)

Description of the analytical methods the US Food and Drug Administration (FDA) uses for testing products to determine if they contain ephedrine alkaloids More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

357

40 CFR 60.474 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...STATIONARY SOURCES Standards of Performance for Asphalt Processing and Asphalt Roofing Manufacture § 60.474 Test methods...of effluent gas, dscm/hr (dscf/hr). P=asphalt roofing production rate or asphalt charging...

2013-07-01

358

8. VIEW OF RADIOGRAPHY EQUIPMENT, TEST METHODS INCLUDED RADIOGRAPHY AND ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VIEW OF RADIOGRAPHY EQUIPMENT, TEST METHODS INCLUDED RADIOGRAPHY AND BETA BACKSCATTERING. (7/13/56) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

359

40 CFR 76.15 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Section 76.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.15 Test methods and procedures. (a) The owner or...

2013-07-01

360

Introduction to Flow Visualization and Optical Testing Methods.  

National Technical Information Service (NTIS)

The classification of optical testing methods is examined, including the interaction of light with a fluid, recording the transmitted light, scattered radiation, and data recording and processing. The analysis of the visualization of surface flow includes...

W. Merzkirch

1986-01-01

361

40 CFR 60.244 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Granular Triple Superphosphate Storage Facilities § 60.244 Test methods and procedures. (a) The...

2013-07-01

362

Electrochemical polishing of thread fastener test specimens of nickel-chromium iron alloys  

DOEpatents

An electrochemical polishing device and method for selective anodic dissolution of the surface of the test specimens comprised, for example, of nickel-chromium-iron alloys, which provides for uniform dissolution at the localized sites to remove metal through the use of a coiled wire electrode (cathode) placed in the immediate proximity of the working, surface resulting in a polished and uniform grain boundary.

Kephart, A.R.

1990-01-01

363

Electrochemical polishing of thread fastener test specimens of nickel-chromium iron alloys  

DOEpatents

An electrochemical polishing device and method for selective anodic dissolution of the surface of test specimens comprised, for example, of nickel-chromium-iron alloys, which provides for uniform dissolution at the localized sites to remove metal through the use of a coiled wire electrode (cathode) placed in the immediate proximity of the working, surface resulting in a polished and uniform grain boundary.

Kephart, Alan R. (Scotia, NY)

1991-01-01

364

Electrochemical polishing of thread fastener test specimens of nickel-chromium iron alloys  

DOEpatents

An electrochemical polishing device and method for selective anodic dissolution of the surface of the test specimens comprised, for example, of nickel-chromium-iron alloys, which provides for uniform dissolution at the localized sites to remove metal through the use of a coiled wire electrode (cathode) placed in the immediate proximity of the working, surface resulting in a polished and uniform grain boundary.

Kephart, A.R.

1990-12-31

365

DISSOLUTION OF ZIRCONIUM AND ALLOYS THEREFOR  

DOEpatents

The dissolution of zirconium cladding in a water solution of ammonium fluoride and ammonium nitrate is described. The method finds particular utility in processing spent fuel elements for nuclear reactors. The zirconium cladding is first dissolved in a water solution of ammonium fluoride and ammonium nitrate; insoluble uranium and plutonium fiuorides formed by attack of the solvent on the fuel materiai of the fuel element are then separated from the solution, and the fuel materiai is dissolved in another solution.

Swanson, J.L.

1961-07-11

366

Bench testing of nebulizers: a comparison of three methods.  

PubMed

Although nebulizers can vary widely in performance, there is no uniformly accepted method for bench testing these devices. In the present study, we compared three bench methods of measuring the performance of three commercial jet nebulizers (Whisper Jet [WJ; Marquest Medical, Englewood, CO], Sidestream [SS; Marquest Medical], and Vixone [VO; Westmed, Tucson, AZ] to assess the impact of the method of testing on reported nebulizer performance. Each nebulizer was charged with 3 mL of albuterol mixed with a radiotracer (technetium [99mTc]), and the radioactivity captured on a paper filter was expressed as a percentage of the nebulizer charge (% delivered). The nebulizers were tested with and without duplication of spontaneous respiration by a piston pump (spontaneous respiration and standing cloud methods, respectively). The nebulizers were also tested using a model of mechanical ventilation (mechanical ventilation method). For all three devices, the addition of the standardized breathing pattern significantly reduced the % delivered with all three nebulizers compared with the standing cloud method. For the standing cloud method, the presence of the T-piece/mouth-piece significantly reduced the % delivered with the WJ but not with the other two devices. The mechanical ventilation method had the lowest % delivered for all three devices. The magnitude of the differences between nebulizers varied with duration of treatment. The findings of this study emphasize the importance of bench testing that duplicates intended clinical usage, because significant differences in nebulizer performance may be manifested under certain clinical conditions but not under others. PMID:10539708

O'Riordan, T G; Weinstein, M D; Mao, Y

1999-01-01

367

Comparison of HEPA filter test methods in corrosive environments  

SciTech Connect

The in-plant testing of process off-gas high efficiency particular air (HEPA) filters is an important quality control activity of the ALARA (As Low As Reasonably Achievable) policy at nuclear facilities. Imprecise and irreproducible data were recorded during DOP testing at the Atmospheric Protection System (APS) of the Idaho Chemical Processing Plant (ICPP). The tests at the APS are performed in an environment that has high humidity, high temperatures and has NO/sub x/ present. An evaluation of three HEPA filter test methods in corrosive environments was conducted: the dioctyl phthalate (DOP) method (US Standard Method ANSI N-101.1-1979) the sodium chloride method (British Standard 3928:1969), and the soda-fluorescein or uranine method (French Standard AFNOR STD NFX 44-011). The effects of high humidity, temperature, and oxides of nitrogen (NO/sub x/) on each method was examined. The effects of each variable and any interaction between variables on the test methods were examined. Recommendations for changes in the standard methods to reduce erratic on-line results are presented.

Murphy, L.P.; Fernandez, S.J.; Motes, B.G.

1980-01-01

368

Alternative methods in toxicology tests: In vitro toxicity  

Microsoft Academic Search

Toxicity testing is required for new chemicals being introduced onto the market. The use of animals in evaluating chemical safety is costly and time consuming. Furthermore, there is the ethical need to develope alternative methods to reduce the required number of animals. The newinvitro assays offer numerous advantages such as speed, reproducibility and control of test conditions, and increased sensitivity.

S. Cinelli; A. Falezza; C. Meli; P. Ciliutti; J. A. Vericat

1991-01-01

369

A method for testing association patterns of social animals  

Microsoft Academic Search

Association indices were originally developed to describe species co-occurrences, but have been used increasingly to measure associations between individuals. However, no statistical method has been published that allows one to test the extent to which the observed association index values differ from those of a randomly associating population. Here, we describe an adaptation of a test developed by Manly (1995,Ecology,76,

LARS BEJDER; DAVID FLETCHER; STEFAN BRÄGER

1998-01-01

370

Leak Test Fixture and Method for Using Same.  

National Technical Information Service (NTIS)

A method and apparatus are described which are especially useful for leak testing seams such as an end closure or joint. The test does not require an enclosed pressurized volume within the article or joint section to be leak checked. A flexible impervious...

L. S. Hawk

1976-01-01

371

A micro-film projector method for psychological tests  

Microsoft Academic Search

Adaptations of the micro-film projection method to the administration of both individual and group psychological tests are described, together with newly designed auxiliary equipment. The author cites examples of the application of this technique, which can be adapted to a variety of testing situations and which seems to be of unusual promise because of the attention value of visual projection.

L. L. Thurstone

1941-01-01

372

An Evaluation of Impact Wrench Vibration Emissions and Test Methods  

Microsoft Academic Search

In the interest of providing more effective evaluations of impact wrench vibration exposures and the development of improved methods for measuring vibration emissions produced by these tools, this study focused on three variables: acceleration measured at the tool surface, vibration exposure duration per test trial, and the amount of torque required to unseat the nuts following a test trial. For

THOMAS W. McDOWELL; R. G. Dong; X. Xu; D. E. Welcome; C. Warren

2008-01-01

373

Well temperature testing---an extension of Slider's method  

Microsoft Academic Search

A new technique has been developed for determination of the formation thermal conductivity, skin factor and contact thermal resistance for boreholes where the temperature recovery process after drilling operations is not completed. Slider suggested a technique for analysing transient pressure tests when conditions are not constant. We extend Slider's method for transient temperature well tests. It assumes that the volumetric

I. M. Kutasov; L. V. Eppelbaum

2007-01-01

374

Advanced tensile testing methods for bulk superconductors at cryogenic temperatures  

Microsoft Academic Search

Tensile tests of bulk high Tc superconductors at room temperature have been generally performed by gluing the bulk specimens to Al-alloy rods. Because of the difference in the coefficient of thermal expansion, thermal stresses were induced at cryogenic temperatures especially near the interface between the specimen and the rods. In this study, tensile testing methods with minimized effect of the

K. Kasaba; H. Teshima; T. Hokari; T. Sato; K. Katagiri; Y. Shoji; A. Murakami; H. Hirano

2006-01-01

375

Comparison of Bulk Sediment and Sediment Elutriate Toxicity Testing Methods  

Microsoft Academic Search

Numerous methods exist for assessing the potential toxicity of sediments in aquatic systems. In this study, the results from\\u000a 10-day bulk sediment toxicity test methods using Hyalella azteca and Chironomus tentans were compared to results from 96-h Pimephales promelas and Ceriodaphnia dubia renewed acute toxicity tests conducted using elutriate samples prepared from the same sediments. The goal of the study

Herman J. Haring; Mark E. Smith; James M. Lazorchak; Philip A. Crocker; Abel Euresti; Melissa C. Wratschko; Michael C. Schaub

2010-01-01

376

New methods for corrosion testing of aluminum alloys  

SciTech Connect

This symposium presents papers on a modification of the EXCO test method for exfoliation corrosion susceptibility in 7XXX, 2XXX, and aluminum-lithium alloys; materials evaluation using wet-dry mixed salt-spray tests; a comparison of potentiodynamic polarization tests with wet-dry mixed salt-spray testing of Al-Mg-Si alloy; an accelerated test for determining microbiological-influenced corrosion resistance of aluminum alloys; and corrosion of aluminum in Al alloys in nitric acid. Attention is also given to exfoliation corrosion testing of Al-Li alloys, damage-based assessment of stress corrosion performances among aluminum, and corrosion fatigue crack growth rate of Al-Li alloy sheet and its weldment. Other papers are on potentiometric and potentiostatic determination of the corrosion rate of welded 2519 aluminum alloy, time-lapse video techniques in the corrosion testing of aluminum alloys, and an examination of the influence of lithium on the repassivation rate of aluminum alloys.

Agarwala, V.S.; Ugiansky, G.M.

1992-01-01

377

Optimized absolute testing method of shift-rotation.  

PubMed

The absolute testing method of shift-rotation that combines the traditional N-position method and Zernike polynomial fitting has been commonly employed in surface metrology. It preserves the high spatial frequency of the surface deviation with the N-position method to obtain the rotationally asymmetric surface deviation, but it suffers the kN? order angular terms errors missed by the N-position method when it calculates the rotationally symmetric surface deviation with the Zernike rotationally symmetric polynomial fitting method. An optimized absolute testing method of shift-rotation is presented in this paper. It considers the missing kN? order errors when the equations of the rotationally symmetric surface deviation are solved. As a result, it is more accurate than the traditional method. Experimental absolute results of spherical surfaces are given. PMID:24085219

Song, Weihong; Wu, Fan; Hou, Xi; Wan, Yongjian

2013-10-01

378

Optical metrology of nano-scale mineral dissolutions using a phase-shift interference microscope  

NASA Astrophysics Data System (ADS)

Solid materials are greater or less soluble on the Earth's surface environment in nano-scale. Dissolution is critical issue for weathering and geo-environmental assessment. Recent advances in nanoscopy are derived from novel topographic method with scanning probe microscopes (AFM, STM, LCM). As another classical but precise method, interferometry is still useful optical tool and enables quick and easy survey of vertical surface topography by utilizing computer processing. We have newly designed a white-light phase-shift interference microscope (PSI-M) for detecting ultra-slow dissolution and precipitation to validate the endurance of artificial barrier system for radioactive waste repository (Ueda et al., 2005) and assess the geologic CO2 storage system. The measurement system is comprised of Maki-type (modified Michelson) phase-shift interferometer, white light source, computer camera, and Ti reaction cell with syringe pump. Minimum resolutions are calculated to be about 0.7 nm for surface-reflection mode and 6.6 nm for back-reflection mode. It takes only 2 s to obtain a phase-shift interferogram. After sequential image acquisitions, we can measure the rates of advance and retreat in real-time at the surface of the specimen in the view field by image-processing. As a benchmark test of surface reflection mode, we carried out a dissolution experiment on BK7 glass in pure H2O flowing at 105 um/s. Result showed 8.7E-5 nm/s of dissolution velocity, corresponding to a rate of ~3um/yr . Measurement at etch pits on calcite (10-14) in pure H2O showed an acceptable dissolution rate of 2.9E-10 mol/cm2/s (Ueda et al., 2005). Another measurement on anorthite (010) in 0.5M of NaCl-NaOH-HCl solutions at 105 um/s flow showed consistent rates of 2.4E-13 to 2.3E-11 mol/cm2/s at pH = 3-12.4 with the previous data (Blum and Stillings, 1995). These results sufficiently confirmed precision of the rate determination with PSI-M. We have further carried out the dissolution measurement on ~100x100x2 um3 smectite (Na-montmorillonite) in NaCl-NaOH solution (pH = 7-14) by back-reflection mode. The obtained rates at (001) were three-order faster (6.9E-10 to 3.6E-8 mol/m2/s) than the data previously reported (e.g., Cama et al., 2000; Yokoyama et al., 2005: ~1E-10 to 1E-12 mol/m2/s) and showed inhomogeneity. It has further been found that dissolution rate at etch-pit is three times accelerated than that at grain edge even at pH = 8. Flow-rate dependency on dissolution rates recognized in NaOH 1.0M solution but in the presence of Na2SiO3 (0.05 to 5.00 mM) suggests that the dissolution of smectite is strongly limited by Si release probably enhanced by flow. Thus, our established PSI-M system can be used to consider the mechanism concerning the dissolution and precipitation by controlling conditions of temperature, pressure, composition, and flow as present in natural system with 2D recognizing the dissolution step and pit.

Satoh, H.; Nishimura, Y.; Tsukamoto, K.; Ueda, A.; Ueta, S.; Kato, K.

2005-12-01

379

Saltcake Dissolution Workshop, FY 1999.  

National Technical Information Service (NTIS)

During the FY 1998 Saltcake Dissolution Workshop, participants identified nine tasks to be performed prior to the FY 1999 workshop. Discussions during the workshop indicated that significant progress was made in each area. The workshop focused on the stre...

E. C. Beahm

2001-01-01

380

Study on method of data standardization in interferometric testing  

NASA Astrophysics Data System (ADS)

As a rule, Interferometers are used to test the figure in the polishing phase of optical component, it could provide advance tutor suggestion for manufacturing. It is unable to get the whole wave-front interferogram usually because phase-shift Interferometry is sensitive to environment vibration, so the exactly interference data of the optical surface could not be obtained. Various spatial point on the tested optical component will be given by calculation method about arithmetic average value of equal accuracy is provied. This paper describes the testing results of optical components in size ?1200mm, it is proved the method could eliminate the vibration effectively and get the standardization data.

Chen, Wei

2010-05-01

381

Grouped Scan Slice Repetition Method for Reducing Test Data Volume and Test Application Time  

NASA Astrophysics Data System (ADS)

This paper presents a grouped scan slice encoding technique using scan slice repetition to simultaneously reduce test data volume and test application time. Using this method, many scan slices that would be incompatible with the conventional selective scan slice method can be encoded as compatible scan slices. Experiments were performed with ISCAS'89 and ITC'99 benchmark circuits, and results show the effectiveness of the proposed method.

Kim, Yongjoon; Yang, Myung-Hoon; Park, Jaeseok; Park, Eunsei; Kang, Sungho

382

Modelling Dissolution in a Temporary Network Context  

Microsoft Academic Search

The dissolution and termination of business relationships attract a growing number of studies. The dominant focus has been on the breakdown of ongoing relationships while temporary networks have been not been adequately studied within the emerging research into relationship dissolution. The two types of temporary network dissolution - abrupt dissolution due to critical events or the failure of relationship management,

OWUSU Richard; HOLMLUND-RYTKÖNEN Maria

383

Testing for trends when there are changes in methods  

SciTech Connect

Data from monitoring projects often include sampling or analytical changes that preclude trend analysis on the entire period of record. A modification of the nonparametric Kendall's test for monotonic trends, which accounts for such changes in the period of record, is described here. This approach blocks the data so that only data collected or analyzed under similar circumstances are compared. Alternatively, when appropriate data exist, data collected using the old method may be calibrated to values expected from the new method. Traditional trend tests may then be applied to resulting data sets. Results from simulations assessing both the power of the blocked test and the standard test performed on calibrated data are presented. The power of the blocked test exceeded the power of the calibration approach only when the calibration error was extremely large. Both the blocking and calibration approaches were applied to and compared for chemical data from Vermont lakes. (Copyright (c) 1993 Kluwer Academic Publishers.)

Newell, A.D.; Blick, D.J.; Hjort, R.C.

1993-01-01

384

Antimycobacterial susceptibility testing methods for natural products research  

Microsoft Academic Search

The emergence of multidrug-resistant strains of Mycobacterium tuberculosis underscores the need of continuous developments on new and efficient methods to determine the susceptibility of isolates of M. tuberculosis in the search for novel antimicrobial agents. Natural products constitute an important source of new drugs, but design and implementation of antimycobacterial susceptibility testing methods are necessary for evaluate the different extracts

Juan Gabriel Bueno Sánchez; Vladimir V. Kouznetsov

2010-01-01

385

Insulator Icing Test Methods, Selection Criteria and Mitigation Alternatives  

Microsoft Academic Search

IEEE-PES Task Forces on insulator icing have been active since 1999 in developing icing test methods and recommending insulator selection criteria. Progress towards this goal included methods for obtaining reproducible results and also modeling of important factors. This paper reports on the progress and work accomplished by the PES Task Forces, serving as input data to the joint DEIS\\/PES task

M. Farzaneh; W. A. Chisholm

2007-01-01

386

New Method For Testing Hermeticity Of Silicon Sensor Structures  

Microsoft Academic Search

SUMMARY A method for testing hermeticity of different wafer bonding processes used in silicon sensor devices is proposed. The method is based on measuring the gas concentration in a sealed silicon cavity by Fourier Transform Infrared spectroscopy (FTIR). The gas concentration and thereby the leakage into the sealed silicon cavity after external pressure exposure is measured by FTIR-absorbance. In this

Martin Nese; R. W. Bernstein; Ib-Rune Johansen; Rudie Spooren

1995-01-01

387

Comparison of Methods for Estimating and Testing Latent Variable Interactions.  

ERIC Educational Resources Information Center

|Used simulation to compare structural equation modeling methods for estimating and testing hypotheses about an interaction between continuous variables. Findings indicate that the two-stage least squares procedure exhibited more bias and lower power than the other methods. The Jaccard-Wan procedure (J. Jaccard and C. Wan, 1995) and maximum…

Moulder, Bradley C.; Algina, James

2002-01-01

388

Collector test methods: Analysis of test methods for the determination of the thermal efficiency of flat-plate collectors  

Microsoft Academic Search

Test methods were evaluated for the determination of the thermal efficiency of flat-plate solar collectors with a liquid as the transfer fluid by means of a mathematical simulation. A comparison of experimental results obtained from tests conducted by the National Bureau of Standards (NBS) and by the International Energy Agency (IEA) with the results of the theoretical analysis shows that

M. Bruck; W. Heindl; H. Koch; G. Schaffar; P. Varga

1979-01-01

389

Method to control the amount of helium during leak testing  

SciTech Connect

The purpose of this paper is to demonstrate a method for limiting the amount of helium administered during leak testing and provide a method for keeping the atmospheric helium in a location to a minimum to eliminate backstreaming into the system. This method utilizes the permeability of a balloon. The transporting of helium to the leak check area is also safer by not requiring a cylinder in the leak check location. Utilizing the many shapes of balloons and partially filling of the balloon, any configuration can deliver helium to the leak location. The balloon I filled for the test fell to the floor with the amount of helium I put into the balloon.

Frank E. Jurvic, Jr.

2002-03-29

390

Field tests of carbon monitoring methods in forestry projects  

SciTech Connect

In response to the emerging scientific consensus on the facts of global climate change, the international Joint Implementation (JI) program provided a pilot phase in which utilities and other industries could finance, among other activities, international efforts to sequester carbon dioxide, a major greenhouse gas. To make JI and its successor mechanisms workable, however, cost-effective methods are needed for monitoring progress in the reduction of greenhouse gas emissions. The papers in this volume describe field test experiences with methods for measuring carbon storage by three types of land use: natural forest, plantation forest, and agroforestry. Each test, in a slightly different land-use situation, contributes to the knowledge of carbon-monitoring methods as experienced in the field. The field tests of the agroforestry guidelines in Guatemala and the Philippines, for example, suggested adaptations in terms of plot size and method of delineating the total area for sampling.

NONE

1999-07-01

391

Ecotoxicity test methods and environmental hazard assessment for engineered nanoparticles.  

PubMed

This paper considers whether current standard ecotoxicity methods are fit for purpose for assessing the hazards of engineered nanoparticles. We conclude that the types of test species and biological endpoints used within standard environmental hazard assessment frameworks are generally appropriate. However, there are areas of considerable uncertainty associated with characterisation of nanoparticle exposure in test systems that apply to all ecotoxicity testing guidelines, except those in which dosing of nanoparticles is oral. These include the way in which the substance is dosed into, and maintained within, the test medium; measurement and characterisation of nanoparticles in the test system; better understanding and reporting of abiotic factors that influence behaviour of nanoparticles in the test medium; and agreement on how dosimetric data should be reported. PMID:18438709

Crane, Mark; Handy, Richard D; Garrod, John; Owen, Richard

2008-04-26

392

The science of USP 1 and 2 dissolution: present challenges and future relevance.  

PubMed

Since its inception, the dissolution test has come under increasing levels of scrutiny regarding its relevance, especially to the correlation of results to levels of drug in blood. The technique is discussed, limited to solid oral dosage forms, beginning with the scientific origins of the dissolution test, followed by a discussion of the roles of dissolution in product development, consistent batch manufacture (QC release), and stability testing. The ultimate role of dissolution testing, "to have the results correlated to in vivo results or in vivo in vitro correlation," is reviewed. The recent debate on mechanical calibration versus performance testing using USP calibrator tablets is presented, followed by a discussion of variability and hydrodynamics of USP Apparatus 1 and Apparatus 2. Finally, the future of dissolution testing is discussed in terms of new initiatives in the industry such as quality by design (QbD), process analytical technology (PAT), and design of experiments (DOE). PMID:19165579

Gray, Vivian; Kelly, Gregg; Xia, Min; Butler, Chris; Thomas, Saji; Mayock, Stephen

2009-01-23

393

Full-scale aircraft impact test for evaluation of impact forces: Part 1, Test plan, test method, and test results  

SciTech Connect

One of the factors considered in the design of critical concrete structures is the estimation of the global elasto-plastic structural response caused by the accidental impact of an aircraft. To estimate the response of the structure, the impact force (the force versus time relationship) must be known. Previous analytical studies have derived the forcing function using the impact velocity of the aircraft and the calculated mass and strength distribution of the aircraft. This paper describes a test conducted on April 19, 1988, at an existing rocket sled facility at Sandia National Laboratories in Albuquerque, New Mexico, USA, in which an actual F-4 Phantom aircraft was impacted at a nominal velocity of 215 m/s into an essentially rigid block of concrete. This was accomplished by supporting the F-4 on four struts that were attached to the sled track by carriage shoes to direct the path of the aircraft. Propulsion was accomplished by two stages of rockets. The concrete target was 'floated' on a set of air bearings. Data acquisition consisted of measurements of the acceleration of the fuselage and engines of the F-4, and measurements of the displacement, velocity and acceleration of the concrete target. High-speed photography recorded the impact process and also permitted the determination of the impact velocity. This paper describes the test plan, method and results, while a companion paper discusses the analyses of the results. 6 refs., 11 figs.

von Riesemann, W.A.; Parrish, R.L.; Bickel, D.C.; Heffelfinger, S.R.; Muto, K.; Sugano, T.; Tsubota, H.; Koshika, N.; Suzuki, M.; Ohrui, S.

1989-03-01

394

Impact of testing styles and testing methods on achievement in general chemistry  

NASA Astrophysics Data System (ADS)

This research conducted at a community college located in Northeast Texas studied testing style and testing methods in relation to achievement in general chemistry. Data was collected and examined from 212 participants. Of these, 143 completed both the MBTI and PEPS surveys. This provided 71 subjects designated as Sensor (S) types for the final phase of the study. The subjects were divided into two groups by performance on the PEPS. One group consisted of subjects that indicated a preference to communicate (test) using a formal/pencil-paper test format (linguistic testing style) and the other subjects indicated a preference to communicate (test) using a hands-on/movement test format (tactile testing style). All subjects were administered both a linguistic and tactile pretest prior to treatment and both a linguistic and tactile posttest after treatment. The data was analyzed using a 2 x 2 ANOVA for significant effects at the p < 0.05 level of confidence. The results indicated a significant interaction effect between the student testing style and test methods. While not conclusive, this study does indicate that the type of testing done in general chemistry may be favoring students with certain types of communication preferences (testing styles). Therefore students with many of the worker characteristics desired by the chemical industry may not be successful in general chemistry and choose a different career path.

Howell, Byron Edward

2001-12-01

395

Dissolution rates of carbonated hydroxyapatite in hydrochloric acid.  

PubMed

Osteoclasts have been shown to dissolve efficiently and effectively the mineral phase of bone by locally controlling the environment surrounding the cell. Although this mineral phase has been identified and well characterized as carbonated hydroxyapatite, there is little understanding of the factors that affect the dissolution properties of this mineral phase. Mimicking the mechanism by which osteoclasts dissolve the mineral phase of bone may provide insight into methods for the decalcification of atherosclerotic mineral deposits in the vascular system. Accordingly, a detailed characterization of the effects of various chemical and mechanical parameters on the dissolution of carbonated hydroxyapatite mineral was investigated in this study. Increases in the mineral dissolution rate (2-10 times) were associated with increases in dissolving solution [H+], osmolality, temperature, and flow rate. Mineral dissolution rate increases (5-8 times) were associated with greater surface area of the mineral and mechanical agitation of the dissolving solution. PMID:11771694

Hankermeyer, Christine R; Ohashi, Kevin L; Delaney, David C; Ross, John; Constantz, Brent R

2002-02-01

396

Calcite Dissolution in Saline Waters  

NASA Astrophysics Data System (ADS)

The specific effect of ionic strength on the reaction kinetics of calcite dissolution in intermediate to high ionic strength (0.5 < I < 6.0) solutions applicable to natural waters has been investigated using classical free-drift methods where all other parameters (mCa2+, PCO2, and T) have been held constant. Both phosphate-free solutions of potassium chloride (KCl) and sodium chloride (NaCl) as the dominant ionic strength determining salt were investigated where calcium concentrations were held constant in all solutions at approximately 0.010 molal. Reaction rates were found to vary significantly as a function of ionic strength of the reacting solution, which we suggest is due to the lowered activity of water with an increase in ionic strength which decreases the rate of cation hydration. When modeled with the general rate equation, R = k(1-Ømega)n, first-order kinetics (n=1) are sufficient to fit the experimental data. Furthermore, the rate constant (k) appears to be a function of the square root of the ionic strength of the reacting solution. These results may have potential applications to the response of the ocean to acidification by fossil fuel CO2 as well as CO2 sequestration in subsurface saline waters in calcium carbonate-hosted reservoirs.

Finneran, D. W.; Morse, J. W.

2007-12-01

397

Applying parameter-estimation methods to recovery-test and slug-test analyses.  

PubMed

Parameter-estimation methods, including an exhaustive-search method and PEST (Parameter ESTimation) software, were applied to recovery-test data and slug-test data to obtain best estimates of transmissivity (T) by minimizing the sums of residuals. Each residual represents the difference between the field-measured water-level value and the value calculated by the appropriate non-linear equation. The exhaustive-search method in both cases involves computing the sums of residuals for an array of transmissivity and storativity values selected by the user for testing. Two new Fortran programs are presented that employ the exhaustive-search method. They utilize Picking's method for analyzing recovery-test data and the analytical equation for analyzing slug-test data derived by Cooper, Bredehoeft, and Papadopulos. Picking's method involves application of the Papadopulos and Cooper's equation for drawdown in finite-diameter wells. Utilizing field data reported in the literature, the estimated transmissivity values from the exhaustive-search methods were compared to the literature values obtained by type-curve matching techniques. The exhaustive-search values corresponded closely to the curve-matching values. Estimates for T were also obtained from recovery-test and slug-test data from two sites in southeastern Pennsylvania. For these sites, the PEST program was also applied to the data to evaluate the accuracy of the exhaustive-search methods. The results from the two methods were generally in good agreement. The two new Fortran programs are practical tools for the hydrogeologist, as they require less time compared to type-curve matching and the PEST method, and they yield accurate estimates of transmissivity. PMID:19930470

Mills, Andrew C

2009-11-20

398

The split-method of ultrasonic nondestructive testing  

Microsoft Academic Search

This article describes a new method of echo-impulse ultrasonic testing based on a new “split-algorithm” for signal formation and processing. Application of a split-algorithm can significantly raise the sensitivity of testing devices (by two–three or more orders) while avoiding the loss of resolving capacity. Experimental results prove the practical importance of split-algorithms. Due to its high sensitivity, the proposed flaw

Igor V. Sokolov

2003-01-01

399

Methods for testing transport models. Second year annual report  

SciTech Connect

Substantial progress has been made over the past year on six aspects of the work supported by this grant. As a result, we have in hand for the first time a fairly complete set of transport models and improved statistical methods for testing them against large databases. We also have initial results of such tests. These results indicate that careful application of presently available transport theories can reasonably well produce a remarkably wide variety of tokamak data.

Singer, C.; Cox, D.

1991-11-14

400

Antimicrobial resistance in campylobacter: susceptibility testing methods and resistance trends.  

PubMed

Most Campylobacter infections are self-limiting but antimicrobial treatment (e.g., macrolides, fluoroquinolones) is necessary in severe or prolonged cases. Susceptibility testing continues to play a critical role in guiding therapy and epidemiological monitoring of resistance. The methods of choice for Campylobacter recommended by the Clinical and Laboratory Standards Institute (CLSI) are agar dilution and broth microdilution, while a disk diffusion method was recently standardized by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Macrolides, quinolones, and tetracyclines are among the common antimicrobials recommended for testing. Molecular determination of Campylobacter resistance via DNA sequencing or PCR-based methods has been performed. High levels of resistance to tetracycline and ciprofloxacin are frequently reported by many national surveillance programs, but resistance to erythromycin and gentamicin in Campylobacter jejuni remains low. Nonetheless, variations in susceptibility observed over time underscore the need for continued public health monitoring of Campylobacter resistance from humans, animals, and food. PMID:23827324

Ge, Beilei; Wang, Fei; Sjölund-Karlsson, Maria; McDermott, Patrick F

2013-07-01

401

Boehmite Dissolution Studies Supporting High Level Waste Pretreatment - 9383  

SciTech Connect

Boehmite is present in significant quantities in several of the Hanford waste tanks. It has been proposed that the boehmite will be dissolved through caustic leaching in the Hanford Waste Treatment Plant currently under construction. Therefore, it is important to fully understand the nature of this dissolution so that the process can be deployed. This research determined the impact of primary control parameters on the boehmite dissolution rate. The impact of aluminate ion on the dissolution kinetics was determined. In addition, other parameters that impact boehmite dissolution, such as free hydroxide concentration and reaction temperature, were also assessed and used to develop a semi-empirical model of the boehmite dissolution process. The understanding derived from this work will be used as the basis to evaluate and improve the planned performance of the Hanford Waste Treatment plant. This work is the first in a series of programs aimed at demonstrating the Waste Treatment Plant dissolution process. This work will be used to develop a simulant of the boehmite-containing Hanford waste. That simulant will then be used in laboratory- and pilot-scale testing to demonstrate the Waste Treatment Plant pretreatment process in an integrated fashion.

Peterson, Reid A.; Russell, Renee L.; Snow, Lanee A.

2009-03-01

402

Test methods for assessing the biological stability of biodegradable waste.  

PubMed

This paper presents some results of investigations for the characterization of waste excavated from closed landfills and of waste sampled during mechanical-biological pretreatment before disposal in landfill. The results reported are those obtained with the tests carried out for the assessment of the biological stability of the waste. Some of the considered tests, such as the ones for the determination of the respiration activity and the biogas production, are well known and have been applied for years; other tests, such as the ones for the determination of BOD5 and COD in leaching test eluate and of the black index, are among the tests considered by the international research community for possible utilization for the evaluation of waste biological stability. Good correlations were found for most of the results obtained, proving the reliability of the test methods used. In particular, the effectiveness of biodegradation during waste pretreatment processes can be easily monitored by measuring the respiration index and/or the BOD5 and COD in leaching test eluate; for the characterization of waste from landfills, the use of respiration index can be recommended. In both cases the COD in leaching test eluate may provide additional useful information especially in the case of low values for the respiration index. Moreover, the black index test may be considered with some limits that will be discussed, providing good results in a simple and cost effective way. PMID:17475468

Cossu, Raffaello; Raga, Roberto

2007-05-01

403

Apparatus and method for defect testing of integrated circuits  

SciTech Connect

An apparatus and method for defect and failure-mechanism testing of integrated circuits (ICs) is disclosed. The apparatus provides an operating voltage, V(DD), to an IC under test and measures a transient voltage component, V(DDT), signal that is produced in response to switching transients that occur as test vectors are provided as inputs to the IC. The amplitude or time delay of the V(DDT) signal can be used to distinguish between defective and defect-free (i.e. known good) ICs. The V(DDT) signal is measured with a transient digitizer, a digital oscilloscope, or with an IC tester that is also used to input the test vectors to the IC. The present invention has applications for IC process development, for the testing of ICs during manufacture, and for qualifying ICs for reliability.

Cole, E.I. Jr.; Soden, J.M.

2000-02-29

404

The depletion and regeneration of dissolution-active sites at the mineral-water interface  

Microsoft Academic Search

The responses of ?-Al2O3 and In2O3 dissolution rates to pH-jumps in flow-through reactors are compared to previous results for ?-Fe2O3 in order to test the following hypothesis: because the same fundamental processes of ligand exchange and detachment of metal centers govern both steady state and nonsteady state dissolution, both the steady state and nonsteady state dissolution rates of these sesquioxides

Sherry D. Samson; Lisa L. Stillings; Carrick M. Eggleston

2000-01-01

405

Dissolution of tailored ceramic nuclear waste forms  

SciTech Connect

Dissolution experiments on polyphase, high alumina tailored ceramic nuclear waste forms developed for the chemical immobilization of Savannah River Plant nuclear waste are described. Three forms of leach tests have been adopted; bulk samples conforming to the Materials Characterization Center Static Leach Test (MCC-1), a powdered sample leach test, and a leach test performed on transmission electron microscope thin foil samples. From analysis of these tests the crystalline phases that preferentially dissolve on leaching and the product phases formed are identified and related to the tailoring and processing schemes used in forming the ceramics. The thin foil sample leaching enables the role of intergranular amorphous phases as short-circuit leaching paths in polyphase ceramics to be investigated.

Clarke, D.R.; Jantzen, C.M.; Harker, A.B.

1982-01-01

406

Comparisons of Methods for Multiple Hypothesis Testing in Neuropsychological Research  

PubMed Central

Hypothesis testing with multiple outcomes requires adjustments to control Type I error inflation, which reduces power to detect significant differences. Maintaining the prechosen Type I error level is challenging when outcomes are correlated. This problem concerns many research areas, including neuropsychological research in which multiple, interrelated assessment measures are common. Standard p value adjustment methods include Bonferroni-, Sidak-, and resampling-class methods. In this report, the authors aimed to develop a multiple hypothesis testing strategy to maximize power while controlling Type I error. The authors conducted a sensitivity analysis, using a neuropsychological dataset, to offer a relative comparison of the methods and a simulation study to compare the robustness of the methods with respect to varying patterns and magnitudes of correlation between outcomes. The results lead them to recommend the Hochberg and Hommel methods (step-up modifications of the Bonferroni method) for mildly correlated outcomes and the step-down minP method (a resampling-based method) for highly correlated outcomes. The authors note caveats regarding the implementation of these methods using available software.

Blakesley, Richard E.; Mazumdar, Sati; Dew, Mary Amanda; Houck, Patricia R.; Tang, Gong; Reynolds, Charles F.; Butters, Meryl A.

2011-01-01

407

Comparison of testing methods for latent-heat-storage devices  

SciTech Connect

ASHRAE Standard 94-77, Method of Testing Thermal Storage Devices Based on Thermal Performance, was developed to allow manufacturers of thermal energy storage devices to compare their products in a meaningful way. When Standard 94-77 was used for thermal energy storage products based on latent heat storage, the Standard was found to be inadequate for comparison of these devices. Standard Project Committee SPC 94.1 was established to devise a Standard that would be adequate for comparing latent heat systems. The purpose of this report is to describe several alternatives to Standard 94-77 and discuss the advantages and disadvantages of each alternative. The discussion focuses on two proposed replacement standards and includes experimental results for each. The experimental results are from tests conducted on a PCM storage tank that uses sodium thiosulphate as the PCM and water as the heat transfer fluid. The experimental arrangement is discussed in detail. The first proposed standard, which is here called the Yu Lwin Method, is substantially based on Standard 94-77. It attempts to solve the deficiencies of the old standard by more carefully defining the parameters associated with the test. In addition, a test for degradation with cycling is proposed as part of the standard. The basis for the charge and discharge tests is a constant inlet temperature to the PCM tank. This method is discussed in detail in Section II. The second proposed standard is that recommended to Project Committee SPC 94.1, as of September, 1982. This proposed standard differs considerably from Standard 94-77 in that the theoretical storage capacity is not part of the analysis, and that constant energy input and output are respectively used in the charge and discharge tests. This method is discussed in detail in Section III. The two proposed standards are compared in Section IV. In addition, this Section discusses other proposed methods. Conclusions and recommendations are presented in Section V.

Cole, R.L.; Hull, J.R.; Lwin, Y.; Cha, Y.S.

1983-02-01

408

Testing methods for the properties of test rig used for solid rocket motors  

NASA Astrophysics Data System (ADS)

A summary on the design, property tests and application experiences of test rigs was presented in this paper. The measuring systems of static characteristic and dynamic characteristic of test rigs were also introduced with attention focused on their composition, technical requirements, operating procedure and data processing methods. Since the largest error in thrust measurement in rig firing tests of solid rocket motors mainly comes from the rig, any measures that can decrease the measurement error in this link will greatly improve the accuracy in the thrust measurement.

Hou, Xiangrong

1994-04-01

409

The new null testing method for the special optical window  

NASA Astrophysics Data System (ADS)

The high speed, high precision and wide range specifications are requirement for the modern aircraft, which the traditional hemispherical dome can't achieve now, and the novel conformal window instead can enhance the aerodynamic performance of the aircraft obviously. To reduce the aerodynamic drag and radar cross-section, the window geometry is generally aspheric in shape. As a result, the involved fabrication and testing processes are much more challenging than that of conventional optics and must be mastered before these windows and systems can be implemented at an acceptable cost and risk. Metrology is one of the critical areas required to advance the conformal window technology. But as the surface of these conformal windows is not the traditional sphere lens, the measurement method for it is infeasible with the conventional optics measurement processes. This paper we express the development of testing technology for the special conformal windows in brief, and emphatically introduces one available novel testing method- a new null testing, and here based on the theory of compensation methods, The principle of Offner's refractive null lens has been extended to test the transmission wavefront through conformal window optics and provide feedback during surface fabrication. a compensator system for the was designed for the conformal window is given which parameters are 100mm for its aperture and two parabolic surface as conformal window, the final residual wavefront error(RMS) of which is less than 1/20?(?=632.8nm).

Huang, Changchun

2009-07-01

410

Modeling of the dissolution of a pharmaceutical compound  

NASA Astrophysics Data System (ADS)

This paper analyses the phenomena encountered in the dissolution of a powder composed by drug crystals using the complementarity between the experimental and numerical approach. A macroscopic model based on the population balance equation was developed to describe dissolution experiments. The population balance equation was discretized and solved with the method of classes. The experiments were performed in a perfectly mixed vessel. Different initial masses of solid particles were introduced. The size distribution of the initial particles was measured by image analysis to take into account the particle anisotropy. For each experiment, the evolution of the concentration during the dissolution process was followed by conductimetry. The concentration measurements show an acceleration of the overall dissolution kinetics at the beginning of the dissolution process, although the undersaturation decreases. This particular behavior suggests that the aggregated powder is first disaggregated under the effect of stirring. The introduction of a fragmentation mechanism in our model has allowed a correct description of the concentration profiles. Intrinsic dissolution kinetics was found to be controlled by mass transfer.

Mangin, D.; Garcia, E.; Gerard, S.; Hoff, C.; Klein, J. P.; Veesler, S.

2006-01-01

411

Testing the infrared method on a mechanical model  

SciTech Connect

The strong-coupling infrared or eikonal approximation, introduced in quantum field theory and heavy-ion-collision analysis, is tested by comparison with the large-scale shape of the exact orbits of a classical, anharmonic oscillator. In an appendix, a joint, nonuniform time-rescaling procedure is suggested as a method for reintroducing previously suppressed high-frequency effects.

Fournier, J. (Centre National de la Recherche Scientifique, Laboratoire Cassini, Observatoire de la Cote d'Azur, B. P. 139, 06003 Nice CEDEX (France)); Fried, H.M. (Laboratoire Cassini, Observatoire de la Cote d'Azur, B. P. 139, 06003 Nice CEDEX (France))

1991-06-01

412

Comparing drop impact test method using strain gauge measurements  

Microsoft Academic Search

In this paper, strain gauges are used to measure the dynamic response during drop impact. A set of high-speed data acquisition system is used to capture the real-time strain response of critical locations. Finite Element Modelling is used to determine where to place the strain gauges. Two board level drop impact test methods, A and B, are compared by the

Y. Liu; F. J. H. G. Kessels; Willem D. van Driel; J. A. S. van Driel; F. L. Sun; G. Q. Zhang

2009-01-01

413

Simulation test method for deterioration of engine crankshaft oil seals  

Microsoft Academic Search

This paper introduces a new simulation test method by using IR analysis which is capable of evaluating the rate of deterioration of VMQ (Silicone) rubber material applied in engine crankshaft seal applications. IR analysis is used to measure the rate of change of the Si-C\\/Si-O ratio which indicates the level of deterioration of VMQ material from the hydrolysis of the

S. Nagasawa; H. Nishina; N. Arase; M. Nakada

1990-01-01

414

Transition Delay Fault Testing of Microprocessors by Spectral Method  

Microsoft Academic Search

We introduce a novel spectral method of delay test generation for microprocessors at the register-transfer level (RTL). Vectors are first generated by an available ATPG tool for transition faults on inputs and outputs of the RTL modules of the circuit. These vectors are analyzed using Hadamard matrices to obtain Walsh function components and random noise levels for each primary input.

Nitin YogiandVishwani; Vishwani D. Agrawal

2007-01-01

415

40 CFR 60.466 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

[Title 40 CFR 60.466] [Code of Federal Regulations (annual...Metal Coil Surface Coating] [Sec. 60.466 - Test methods and procedures.] 40...2009-07-01 2009-07-01 false 60.466 Sec. 60.466 PROTECTION OF...

2009-07-01

416

Nondestructive testing methods for 55-gallon, waste storage drums  

Microsoft Academic Search

The Westinghouse Hanford Company (WHC) authorized Pacific Northwest Laboratory (PNL) to conduct a feasibility study to identify promising nondestructive testing (NDT) methods for detecting general and localized (both pitting and pinhole) corrosion in the 55-gal drums that are used to store solid waste materials at the Hanford Site. This document presents results obtained during a literature survey, identifies the relevant

R. H. Ferris; B. P. Hildebrand; R. L. Hockey; D. M. Riechers; J. C. Spanner; D. R. Duncan

1993-01-01

417

40 CFR 60.534 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...of Performance for New Residential Wood Heaters § 60.534 Test methods and procedures...qualifies under the definition of wood heater in § 60.531(a). If such a determination...the overall thermal efficiency of wood heaters. (To be proposed...

2013-07-01

418

EMC Data Collection Techniques: Test methods CE and CS.  

National Technical Information Service (NTIS)

An evaluation of the present specifications for conducted interference in MIL-STD-461A and 462 is reported. The basis for setting limits is reviewed, and the test methods presently called for are applied to several types of communications and radar equipm...

F. Haber K. H. Dolls R. M. Showers R. J. Doviak C. S. Yablik

1969-01-01

419

Computer Controlled Oral Test Administration: A Method and Example.  

ERIC Educational Resources Information Center

A computer/tape recorder interface was designed, which permits automatic oral adminstration of "true-false" or "multiple-choice" type tests. This paper describes the hardware and control program software, which were developed to implement the method on a DEC PDP 11 computer. (Author/JKS)

Milligan, W. Lloyd

1978-01-01

420

40 CFR 60.74 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

... Standards of Performance for Nitric Acid Plants § 60.74 Test methods...ton (lb/ton) of 100 percent nitric acid. Cs =concentration of NOX...hr (ton/hr) or 100 percent nitric acid. K=conversion factor,...

2013-07-01

421

40 CFR 60.404 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

... Standards of Performance for Phosphate Rock Plants § 60.404 Test methods and...matter, kg/Mg (lb/ton) of phosphate rock feed. cs =concentration of particulate...dscm/hr (dscf/hr). P=phosphate rock feed rate, Mg/hr (ton/hr)....

2013-07-01

422

FIELD TEST OF A GENERIC METHOD FOR HALOGENATED HYDROCARBONS  

EPA Science Inventory

Validation of a method for a particular analyte or group of analytes means that the performance of the sampling and analytical methodology for these analytes has been established and demonstrated through field tests at the type of source category of interest: that is, the precisi...

423

Quasi-Monte Carlo methods in cash flow testing simulations  

Microsoft Academic Search

What actuaries call cash flow testing is a large-scale simulation pitting a company's current policy obligation against future earnings based on interest rates. While life contingency issues associated with contract payoff are a mainstay of the actuarial sciences, modeling the random fluctuations of US Treasury rates is less studied. Furthermore, applying standard simulation techniques, such as the Monte Carlo method,

Michael G. Hilgers

2000-01-01

424

Novel quantitative non-destructive testing method for composite structures  

Microsoft Academic Search

A novel QNDT (quantitative non-destructive testing) method is developed that is combined with a phase-shifting shearing speckle and thermograph, and, it aims at the detection of faults such as cracks, voids, delamination and weak areas. The technique is immune to ambient noise and is suitable for measuring the in situ environment. Some different depth defects that would produce deformation differing

Jin-long Chen; Yu-wen Qin; Hong-wei Ji; Xin-hua Ji

1998-01-01

425

The bubble test: an atraumatic method for canalicular laceration repair.  

PubMed

Canalicular lacerations need to be correctly identified before surgical repair. Methods to find the medial cut end are numerous. With the use of direct sight or the bubble test or both, the identification and repair of the medial cut end of the lacerated canaliculus should be achievable in the majority of cases. PMID:8652461

Loff, H J; Wobig, J L; Dailey, R A

1996-03-01

426

Comparative study of heuristic evaluation and usability testing methods  

PubMed Central

Usability methods, such as heuristic evaluation, cognitive walk-throughs and user testing, are increasingly used to evaluate and improve the design of clinical software applications. However, there is still some uncertainty as to how those methods can be used to support the development process and evaluation in the most meaningful manner. In this study, we compared the results of a heuristic evaluation with those of formal user tests in order to determine which usability problems were detected by both methods. We conducted heuristic evaluation and usability testing on four major commercial dental computer-based patient records (CPRs) which together cover 80% of the market for chairside computer systems among general dentists. Both methods yielded strong evidence that the dental CPRs have significant usability problems. An average of 50% of empirically determined usability problems were identified by the preceding heuristic evaluation. Some statements of heuristic violations were specific enough to precisely identify the actual usability problem that study participants encountered. Other violations were less specific, but still manifested themselves in usability problems and poor task outcomes. In this study, heuristic evaluation identified a significant portion of problems found during usability testing. While we make no assumptions about the generalizability of the results to other domains and software systems, heuristic evaluation may, under certain circumstances, be a useful tool to determine design problems early in the development cycle.

Thyvalikakath, Thankam Paul; Monaco, Valerie; Thambuganipalle, Himabindu; Schleyer, Titus

2009-01-01

427

Studies on sulfate attack: Mechanisms, test methods, and modeling  

Microsoft Academic Search

The objective of this research study was to investigate various issues pertaining to the mechanism, testing methods, and modeling of sulfate attack in concrete. The study was divided into the following segments: (1) effect of gypsum formation on the expansion of mortars, (2) attack by the magnesium ion, (3) sulfate attack in the presence of chloride ions---differentiating seawater and groundwater

Manu Santhanam

2001-01-01

428

16 CFR 1610.3 - Summary of test method.  

Code of Federal Regulations, 2013 CFR

...STANDARD FOR THE FLAMMABILITY OF CLOTHING TEXTILES The Standard § 1610.3 Summary...methods of testing the flammability of textiles from or intended to be used for apparel...forth the requirements for classifying textiles; and prohibits the use of single...

2013-01-01

429

40 CFR 60.335 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Standards of Performance for Stationary Gas Turbines § 60.335 Test methods and procedures...for: Lean premix stationary combustion turbines; units used in association with heat...the normal operating range of the gas turbine, including the minimum point in...

2013-07-01

430

Comparison of Testing Methods for Latent-Heat-Storage Devices.  

National Technical Information Service (NTIS)

ASHRAE Standard 94-77, Method of Testing Thermal Storage Devices Based on Thermal Performance, was developed to allow manufacturers of thermal energy storage devices to compare their products in a meaningful way. When Standard 94-77 was used for thermal e...

R. L. Cole J. R. Hull Y. Lwin Y. S. Cha

1983-01-01

431

System and Method for Field Testing a Tack Coat Layer.  

National Technical Information Service (NTIS)

Methods and systems are disclosed for evaluating an adhesive layer such as a tack coat. In one embodiment, a portable apparatus is provided to test a tack coat layer prior to applying an overlay. The portable apparatus includes a tripod configuration plac...

V. Tandon

2004-01-01

432

Nondestructive testing method of concrete using impact acoustics  

Microsoft Academic Search

A new nondestructive testing method for concrete using impact acoustics is investigated. Impact acoustics, which has a strong relation with the vibration of a concrete surface, can offer important information about the physical properties of concrete structures such as shapes, material properties and defects. In this paper, the relation between impact acoustics and vibration at the same surface of the

Y. Ito; T. Uomoto

1997-01-01

433

40 CFR 61.174 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Standard for Inorganic Arsenic Emissions From Primary Copper Smelters § 61.174 Test methods and procedures...effective date of this subpart in the case of an existing copper converter or a copper converter that has an initial startup date...

2013-07-01

434

Partitioning Methods for Detecting Misconceptions of Content and Test Items.  

ERIC Educational Resources Information Center

Two studies evaluated partitioning methods, in order to study how items are perceived by students and to determine how students organize content. Achievement test items in five content areas of educational measurement were used as stimuli to be sorted by groups of students who varied in sophistication. (Author/CTM)

Ambrosino, Robert J.; And Others

1979-01-01

435

TROPICAL COLLECTOR URCHIN, TRIPNEUSTES GRATILLA, FERTILIZATION TEST METHOD  

EPA Science Inventory

This document describes a fertilization method to estimate the chronic toxicity of effluents and receiving waters to the gametes of the tropical sea urchin (Tripneustes gratilla). This toxicity test measures the fertilizing capacity of sperm following a static, non-renewal 60-mi...

436

An automated dynamic water vapor permeation test method  

NASA Astrophysics Data System (ADS)

This report describes an automated apparatus developed to measure the transport of water vapor through materials under a variety of conditions. The apparatus is more convenient to use than the traditional test methods for textiles and clothing materials, and allows one to use a wider variety of test conditions to investigate the concentration-dependent and nonlinear transport behavior of many of the semipermeable membrane laminates which are now available. The dynamic moisture permeation cell (DMPC) has been automated to permit multiple setpoint testing under computer control, and to facilitate investigation of transient phenomena. Results generated with the DMPC are in agreement with and of comparable accuracy to those from the ISO 11092 (sweating guarded hot plate) method of measuring water vapor permeability.

Gibson, Phillip; Kendrick, Cyrus; Rivin, Donald; Charmchii, Majid; Sicuranza, Linda

1995-05-01

437

Hydrocode Simulation of Wedge Tests to Determine How the Test Method Affects the Pop Plot  

NASA Astrophysics Data System (ADS)

Most of the available shock reactivity data for explosives comes from either wedge tests or from embedded gauge data obtained from flyer plate tests. A question arises, what effect does the test method have on the Pop Plot obtained? A flyer plate test will impart a constant input pressure whereas wedge testing using a plane wave lens (PWL) system will not. To gauge this effect, explicit numerical simulations were performed for 4'' and 8'' diameter wedge tests using a PWL system and for flyer plate impact tests. For the flyer plate tests, the simulations modeled the flyer plate and explosive sample. For the PWL system, the simulations modeled the PWL, the booster explosive, the attenuator and the explosive sample. The simulations resulted in distance-time curves of the shock or detonation wave traveling into the sample. These curves, when differentiated, resulted in shock velocity versus distance and shock velocity versus time plots. Inspection of these plots for various input pressures allowed for prediction of pop plots (log of run distance versus log of time and log of run distance versus log of input pressure). Comparison of the Pop Plots indicated the effect of the test method on Pop Plot slope and intercept. Simulations were performed for both an ideal and a non-ideal explosive.

Sutherland, Gerrit

2011-06-01

438

The effect of additives on lime dissolution rates. Final report  

SciTech Connect

Based on the previous years` studies concerning the efficiency of SO{sub 2} removal by spray dryers with high sulfur coal flue gas, the work for year five included investigations of lime dissolution rates at different slaking conditions and with the effect of additives. The prominent additives that have significant effects on lime dissolution rates were tested with the mini pilot spray drying absorber to see their effects on spray drying desulfurization applications. The mechanisms of these additive effects along with the properties of hygroscopic additives have been discussed and incorporated into the spray drying desulfurization model ``SPRAYMOD-M.`` Slaking conditions are very important factors in producing high quality lime slurry in spray drying desulfurization processes. At optimal slaking conditions, the slaked lime particles are very fine (3-5{mu}m) and the slaked lime has high BET surface areas which are beneficial to the desulfurization. The slaked lime dissolution rate experiments in our study are designed to determine how much lime can dissolve in a unit time if the initial lime surface area is kept constant. The purpose of the dissolution rate study for different additives is to find those effective additives that can enhance lime dissolution rates and to investigate the mechanisms of the dissolution rate enhancement properties for these additives. The applications of these additives on spray drying desulfurization are to further verify the theory that dissolution rate is a rate limiting step in the whole spray drying desulfurization process as well as to test the feasibility of these additives on enhancing SO{sub 2} removal in spray dryers.

Khang, S.J.

1996-07-31

439

Investigating the relationship between drug distribution in solid lipid matrices and dissolution behaviour using Raman spectroscopy and mapping.  

PubMed

In this study, in situ and mapping Raman spectroscopic measurements were used to investigate the physical structure of solid lipid extrudates and relate the structure to dissolution behaviour. Theophylline anhydrate was extruded with tripalmitin, with and without the water-soluble polymer, polyethylene glycol 10000. Raman mapping of the extrudate cores revealed that drug particles of diverse size were dispersed in a continuous lipid phase with or without polyethylene glycol. At the surface, there was evidence of more mixing between the components. Previous characterisation by other methods suggested that the extrudate surface is covered predominantly by lipid, and the Raman mapping suggested that such a layer is in general less than a few micrometres thick. Nevertheless, the lipid layer dramatically reduced the drug dissolution rate. The extrudate cores were also mapped after a period of dissolution testing, and there was no evidence of a uniformly receding drug boundary in the extrudates during drug release. In situ Raman spectroscopy analysis during dissolution testing revealed that the drug distribution in the extrudate affected the formation of theophylline monohydrate. However, the drug release rate was primarily determined directly by drug distribution, with the solid-state behaviour of the drug having a smaller influence. PMID:19691104

Windbergs, Maike; Haaser, Miriam; McGoverin, Cushla M; Gordon, Keith C; Kleinebudde, Peter; Strachan, Clare J

2010-03-01

440

High Level Waste System Impacts from Acid Dissolution of Sludge  

SciTech Connect

This research evaluates the ability of OLI{copyright} equilibrium based software to forecast Savannah River Site High Level Waste system impacts from oxalic acid dissolution of Tank 1-15 sludge heels. Without further laboratory and field testing, only the use of oxalic acid can be considered plausible to support sludge heel dissolution on multiple tanks. Using OLI{copyright} and available test results, a dissolution model is constructed and validated. Material and energy balances, coupled with the model, identify potential safety concerns. Overpressurization and overheating are shown to be unlikely. Corrosion induced hydrogen could, however, overwhelm the tank ventilation. While pH adjustment can restore the minimal hydrogen generation, resultant precipitates will notably increase the sludge volume. OLI{copyright} is used to develop a flowsheet such that additional sludge vitrification canisters and other negative system impacts are minimized. Sensitivity analyses are used to assess the processability impacts from variations in the sludge/quantities of acids.

KETUSKY, EDWARD

2006-04-20

441

Solution-mediated phase transformation of salts during dissolution: investigation using haloperidol as a model drug.  

PubMed

Soluble salts can undergo solution-mediated phase transformation to a lower solubility form due to pH gradients in the gastrointestinal tract. Therefore, dissolution rate rather than solubility may be the best predictor of bioavailability for such compounds. The purpose of this project was to examine the kinetics of the conversion of a basic compound, haloperidol, and its salt forms using a flow-through dissolution apparatus and rotating disk method in neutral conditions. The effects of buffer concentration, salt form, dissolution apparatus, and hydrodynamics were examined. Raman microscopy was used to characterize solids after dissolution. Haloperidol mesylate and haloperidol chloride showed a decrease in dissolution rate with time in the dissolution media. Haloperidol mesylate and haloperidol chloride dissolution rates also decreased with increasing buffer capacity. Raman microscopy confirmed phase conversion from the salt forms to the free base form in phosphate buffer. Hydrodynamics did not affect the time course of the solution-mediated phase transformation of salt forms. Dissolution and precipitation appear to be a function of pH close to the surface of the dissolving solid. In situations where equilibrium solubility of salts cannot be assessed experimentally, dissolution experiments are useful for examining the extent and duration of the dissolution rate enhancement. PMID:21328581

Greco, Kristyn; Mcnamara, Daniel P; Bogner, Robin

2011-02-16

442

[Clinical application of testing methods on acid-fast bacteria].  

PubMed

Clinical bacteriology pertaining to acid-fast bacteria has made marked advances over the past decade, initiated by the development of a DNA probe kit for identification of acid-fast bacteria. Wide-spread use of nucleic acid amplification for rapid detection of tubercle bacillus contributed more greatly than any other factor to such advances in this field. At present, 90% of all kits used for nucleic acid amplification in the world are consumed in Japan. Unfortunately, not a few clinicians in Japan have a false idea that the smear method and nucleic acid amplification are necessary but culture is not. In any event nucleic acid amplification has exerted significant impacts on the routine works at bacteriology laboratories. Among others, collecting bacteria by pretreatment with NALC-NaOH has simplified the introduction of the collective mode smear method and liquid media. Furthermore, as clinicians have become increasingly more experienced with various methods of molecular biology, it now seems possible to apply these techniques for detection of genes encoding drug resistance and for utilization of molecular epidemiology in routine laboratory works. Meanwhile, attempts to diagnose acid-fast bacteriosis by checking blood for antibody have also been made, primarily in Japan. At present, two kits for detecting antibodies to glycolipids (LAM, TDM, etc.) are covered by national health insurance in Japan. We have an impression that in Japan clinicians do not have adequate knowledge and skill to make full use of these new testing methods clinically. We, as the chairmen of this symposium, hope that this symposium will help clinicians increase their skill related to new testing methods, eventually leading to stimulation of advances in clinical practices related to acid-fast bacteria in Japan. 1. Smear microscopy by concentration method and broth culture system: Kazunari TSUYUGUCHI (Clinical Research Center, National Hospital Organization Kinki-chuo Chest Medical Center) Smear microscopy and culture still remain the cornerstone to diagnose tuberculosis. However, the classical methods in Japan using direct microscopy and Ogawa solid media were not sufficient for clinical use. In recent years substantial advance has been made in these fields. Concentration of clinical samples by centrifugation improves the sensitivity of smear microscopy with excellent reproducibility. The Mycobacteria Growth Indicator Tube (MGIT) system using liquid media yields high sensitivity and rapidity. Using these methods, more and more tuberculosis cases would be correctly diagnosed and treated adequately based on drug susceptibility testing. 2. New technologies for anti-tuberculosis drug susceptibility testing: Satoshi MITARAI (Bacteriology Division, Reference Centre for Mycobacterium, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association) Several new technologies have been developed to obtain anti-tuberculosis drug susceptibility testing (AST) results rapidly, utilising liquid culture and molecular technologies. Mycobacterium Growth Indicator Tube (MGIT), as a popular liquid culturing and AST system, was evaluated for its accuracy and usefulness. As for isoniazid, MGIT showed 12.6% of discordant result comparing with standard method. These MGIT resistant and Ogawa susceptible strains had relatively high MICs ranging 0.13 to 2.0 microg/ml. The molecular detection of resistant gene mutation is also a useful method to estimate drug resistance rapidly. The rpoB mutation detection is reliable with high sensitivity and specificity. 3. Nucleic acid amplification and novel diagnostic methods: Shunji TAKAKURA (Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine) Sensitivities of nucleic acid amplification tests (NAATs) for the diagnosis of tuberculosis meet clinical requirement that patients with high-risk of transmission should be identified within a day. Comparison of the performance of various NAATs is difficult because of the difference in sample processing and in samples tested among methods and reports. Con

Ichiyama, Satoshi; Suzuki, Katsuhiro

2005-02-01

443

An experimental study of the kinetics of lherzolite reactive dissolution with applications to melt channel formation  

Microsoft Academic Search

The kinetics of lherzolite dissolution in an alkali basalt and a basaltic andesite was examined experimentally at 1,300°C and 1 GPa using the dissolution couple method. Dissolution of lherzolite in basaltic liquids produces either the melt-bearing dunite–harzburgite–lherzolite (DHL) sequence or the melt-bearing harzburgite–lherzolite sequence depending on whether the reacting melt is or close to olivine saturation (alkali basalt) or olivine + orthopyroxene saturation

Zachary Morgan; Yan Liang

2005-01-01

444

THE DISSOLUTION RATE OF Ca(OH)2 IN AQUEOUS SOLUTIONS  

Microsoft Academic Search

The dissolution rate of reagent grade Ca(OH)2 in aqueous solutions has been determined by means of a spinning disc method. The dissolution rate was found to be independent of disc velocity at a disc Reynold's Number above 9×l0. The dissolution rate is important for environmental applications such as flue gas desulfurization using Ca(OH)2 in wet scrubbers and spray dryer reactors,

JUN WANG; TIM C. KEENER; GUANG LI; SOON-JAI KHANG

1998-01-01

445

Dissolution rate of limestone for wet flue gas desulfurization in the presence of sulfite  

Microsoft Academic Search

Limestone dissolution rate was measured by a pH-stat method with CO2 sparging and dissolved sulfite. The dissolution rate of limestone under these conditions was found to be controlled by mass transfer and surface kinetics. As can be seen from the results, in the presence of sulfite, limestone dissolution rate increases with increasing stirring speed, reaction temperature and CO2 partial pressure.

Gao Xiang; Guo Rui-tang; Ding Hong-lei; Luo Zhong-yang; Cen Ke-fa

2009-01-01

446

The role of soil pH in the dissolution of phosphate rock fertilizers  

Microsoft Academic Search

The influence of soil pH on the dissolution of phosphate rock fertilizers was investigated in laboratory experiments with reactive North Carolina phosphate rock (PR) in a lateritic soil adjusted to several pH values. Increased soil pH resulted in decreased dissolution as estimated by the increase in exchangeable calcium (?Ca) method. The extent of PR dissolution was related to soil pH

I. A. K. Kanabo; R. J. Gilkes

1987-01-01

447

Dissolution behavior of alumina in mold fluxes for steel continuous casting  

Microsoft Academic Search

Dissolution of alumina in various mold fluxes for steel continuous casting has been investigated by employing the rotating\\u000a cylinder method. The weight loss of the rod, the dipping area and the immersed time were measured to determine dissolution\\u000a rate of Al2O3. The dissolution rate increased with temperature of molten fluxes, the rotating speed of the rod and the addition of

Anh-Hoa Bui; Hyun-Mo Ha; Youn-Bae Kang; In-Sang Chung; Hae-Geon Lee

2005-01-01

448

Dissolution behavior of zirconia-refractories during continuous casting of steel  

Microsoft Academic Search

Dissolution behavior of ZrO2-graphite refractories used in a submerged entry nozzle (SEN) during continuous casting of steel was investigated using the\\u000a rotating cylinder method. In the present work, the dissolution rate of the zirconia-graphite rod was determined by measuring\\u000a the corrosion depth of the rod after a given immersion time. It was found that the dissolution rate was slow at

Anh-Hoa Bui; Sang-Chae Park; In-Sang Chung; Hae-Geon Lee

2006-01-01

449

Intracranial endovascular balloon test occlusion: indications, methods, and predictive value.  

PubMed

Abrupt interruption of the internal carotid artery without a balloon test occlusion (BTO) carries a 26% risk of cerebral infarction. BTO is a test used to decrease this risk by evaluating the efficacy of the collateral circulation. Clinical tolerance of parent vessel occlusion can be assessed by a BTO with several variables, including the clinical examination, angiographic assessment, stump pressure, induced hypotension, perfusion scanning, transcranial Doppler ultrasonography, and neurophysiologic monitoring. This review discusses the indications, methods, predictive value, and complications of BTO. PMID:24156859

Elias, Augusto E; Chaudhary, Neeraj; Pandey, Aditya S; Gemmete, Joseph J

2013-05-30

450

CPV solar receiver ageing tests: The enhanced electroluminescence method  

NASA Astrophysics Data System (ADS)

For two years now, CEA INES is involved in the development of insulated metal substrates (IMS) for CPV receivers. In an effort for establishing the reliability of such a new design compared to state-of-the-art direct bonded copper (DBC) design, accelerated ageing test have been carried out. During these tests, several characterization tools were used including current voltage measurements, X-ray tomography and electroluminescence. A new method for the characterization of thermal inhomogeneities has been developed, the so-called Enhanced Electroluminescence (EEL) which is described in this paper.

Mabille, Loïc; Mangeant, Christophe; Baudrit, Mathieu

2013-09-01

451

Methods of and apparatus for testing the integrity of filters  

DOEpatents

A method of and apparatus for testing the integrity of individual filters or filter stages of a multistage filtering system including a diffuser permanently mounted upstream and/or downstream of the filter stage to be tested for generating pressure differentials to create sufficient turbulence for uniformly dispersing trace agent particles within the airstram upstream and downstream of such filter stage. Samples of the particel concentration are taken upstream and downstream of the filter stage for comparison to determine the extent of particle leakage past the filter stage.

Herman, R.L.

1984-01-01

452

Method of and apparatus for testing the integrity of filters  

DOEpatents

A method of and apparatus for testing the integrity of individual filters or filter stages of a multistage filtering system including a diffuser permanently mounted upstream and/or downstream of the filter stage to be tested for generating pressure differentials to create sufficient turbulence for uniformly dispersing trace agent particles within the airstream upstream and downstream of such filter stage. Samples of the particle concentration are taken upstream and downstream of the filter stage for comparison to determine the extent of particle leakage past the filter stage.

Herman, Raymond L [Richland, WA

1985-01-01

453

Method of and apparatus for testing the integrity of filters  

DOEpatents

A method of and apparatus are disclosed for testing the integrity of individual filters or filter stages of a multistage filtering system including a diffuser permanently mounted upstream and/or downstream of the filter stage to be tested for generating pressure differentials to create sufficient turbulence for uniformly dispersing trace agent particles within the airstream upstream and downstream of such filter stage. Samples of the particle concentration are taken upstream and downstream of the filter stage for comparison to determine the extent of particle leakage past the filter stage. 5 figs.

Herman, R.L.

1985-05-07

454

Laboratory simulation of salt dissolution during waste removal  

SciTech Connect

Laboratory experiments were performed to support the field demonstration of improved techniques for salt dissolution in waste tanks at the Savannah River Site. The tests were designed to investigate three density driven techniques for salt dissolution: (1) Drain-Add-Sit-Remove, (2) Modified Density Gradient, and (3) Continuous Salt Mining. Salt dissolution was observed to be a very rapid process as salt solutions with densities between 1.38-1.4 were frequently removed. Slower addition and removal rates and locating the outlet line at deeper levels below the top of the saltcake provided the best contact between the dissolution water and the saltcake. It was observed that dissolution with 1 M sodium hydroxide solution resulted in salt solutions that were within the current inhibitor requirements for the prevention of stress corrosion cracking. This result was independent of the density driven technique. However, if inhibited water (0.01 M sodium hydroxide and 0.011 M sodium nitrite) was utilized, the salt solutions were frequently outside the inhibitor requirements. Corrosion testing at conditions similar to the environments expected during waste removal was recommended.

Wiersma, B.J.; Parish, W.R.

1997-01-01

455

Systematic review of forsterite dissolution rate data  

NASA Astrophysics Data System (ADS)

This paper demonstrates a method for systematic analysis of published mineral dissolution rate data using forsterite dissolution as an example. The steps of the method are: (1) identify the data sources, (2) select the data, (3) tabulate the data, (4) analyze the data to produce a model, and (5) report the results. This method allows for a combination of critical selection of data, based on expert knowledge of theoretical expectations and experimental pitfalls, and meta-analysis of the data using statistical methods. Application of this method to all currently available forsterite dissolution rates (0 < pH < 14, and 0 < T < 150 °C) normalized to geometric surface area produced the following rate equations: For pH < 5.6 and 0° < T < 150 °C, based on 519 data logr=6.05(0.22)-0.46(0.02)pH-3683.0(63.6)1/T(R2=0.88) For pH > 5.6 and 0° < T < 150 °C, based on 125 data logr=4.07(0.38)-0.256(0.023)pH-3465(139)1/T(R2=0.92) The R2 values show that ˜10% of the variance in r is not explained by variation in 1/T and pH. Although the experimental error for rate measurements should be ± ˜30%, the observed error associated with the log r values is ˜0.5 log units (±300% relative error). The unexplained variance and the large error associated with the reported rates likely arises from the assumption that the rates are directly proportional to the mineral surface area (geometric or BET) when the rate is actually controlled by the concentration and relative reactivity of surface sites, which may be a function of duration of reaction. Related to these surface area terms are other likely sources of error that include composition and preparation of mineral starting material. Similar rate equations were produced from BET surface area normalized rates. Comparison of rate models based on geometric and BET normalized rates offers no support for choosing one normalization method over the other. However, practical considerations support the use of geometric surface area normalization. Comparison of Mg and Si release rates showed that they produced statistically indistinguishable dissolution rates because dissolution was stoichiometric in the experiments over the entire pH range even though the surface concentrations of Mg and Si are known to change with pH. Comparison of rates from experiments with added carbonate, either from CO2 partial pressures greater than atmospheric or added carbonate salts, showed that the existing data set is not sufficient to quantify any effect of dissolved carbonate species on forsterite dissolution rates.

Rimstidt, J. Donald; Brantley, Susan L.; Olsen, Amanda A.

2012-12-01

456
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