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1

Dissolution Testing  

Microsoft Academic Search

Ever since dissolution was known to have a significant effect on bioavailability and clinical performance, dissolution analysis\\u000a of pharmaceutical solids has become one of the most important tests in drug product development and manufacturing, as well\\u000a as in regulatory assessment of drug product quality. Not only can dissolution testing provide information regarding the rate\\u000a and extent of drug absorption in

Sau Lawrence Lee; Andre S. Raw; Lawrence Yu

2

Studies on dissolution tests for soft gelatin capsules. IV. Dissolution test of nifedipine soft gelatin capsule containing water soluble vehicles by the rotating dialysis cell method.  

PubMed

The dissolution of oval soft gelatin capsules containing 5 mg of nifedipine dissolved in a water soluble vehicle was evaluated by the rotating dialysis cell (RDC) method and the paddle (PD) method as described in the Japanese Pharmacopoiea (JP) XI. The dissolution pattern of nifedipine obtained by the PD method was linear, and almost 100% of the content was dissolved within 7 to 10 min. The dissolution pattern obtained by the RDC method corresponded to the absorption pattern vs. time curve obtained by th oral administration test in humans. When the RDC method was performed with the cell containing a buffered solution coupled with n-octanol as the dissolution medium, the in vitro dissolution pattern best simulated the in vivo absorption pattern. PMID:8149460

Takahashi, M; Mochizuki, M; Itoh, T; Ohta, M

1994-02-01

3

Development of a standardized dissolution test method for inhaled pharmaceutical formulations.  

PubMed

The aim of this research was to investigate a potential standardized test method to characterize the dissolution properties of formulations intended for pulmonary delivery. A commercially available dissolution tester was adapted to be used as a testing apparatus by incorporation of a membrane containing cassette. The cassette was designed to enclose previously air-classified formulations, so that they could be uniformly tested in the dissolution apparatus. The influence of particle size, amount of drug loading, and the composition of a simulated lung fluid (SLF) dissolution media on the dissolution rate were studied. Dissolution rate was significantly affected by the uniformity of drug loading, and particle size. Diffusion coefficients, estimated using the Higuchi model, showed an increase from 2.28 to 9.60x10(-7) cm(2)/h as the particle size decreased. Addition of DPPC (0.02%, w/v) to the SLF dissolution media resulted also resulted in an increase in the diffusion coefficient value. This study demonstrated that the developed method was reproducible and may be used to evaluate the dissolution properties of pharmaceutical inhalation products following their aerodynamic particle classification. PMID:19665533

Son, Yoen-Ju; McConville, Jason T

2009-12-01

4

Small Volume Dissolution Testing as a Powerful Method during Pharmaceutical Development  

PubMed Central

Standard compendia dissolution apparatus are the first choice for development of new dissolution methods. Nevertheless, limitations coming from the amount of material available, analytical sensitivity, lack of discrimination or biorelevance may warrant the use of non compendial methods. In this regard, the use of small volume dissolution methods offers strong advantages. The present study aims primarily to evaluate the dissolution performance of various drug products having different release mechanisms, using commercially available small volume USP2 dissolution equipment. The present series of tests indicate that the small volume dissolution is a useful tool for the characterization of immediate release drug product. Depending on the release mechanism, different speed factors are proposed to mimic common one liter vessel performance. In addition, by increasing the discriminating power of the dissolution method, it potentially improves know how about formulations and on typical events which are evaluated during pharmaceutical development such as ageing or scale–up. In this regard, small volume dissolution is a method of choice in case of screening for critical quality attributes of rapidly dissolving tablets, where it is often difficult to detect differences using standard working conditions.

Emmanuel, Scheubel; Marc, Lindenberg; Eric, Beyssac; Jean-Michel, Cardot

2010-01-01

5

Simulating the postprandial stomach: biorelevant test methods for the estimation of intragastric drug dissolution.  

PubMed

Intragastric drug release from solid oral dosage forms can be affected by altered physicochemical and mechanical conditions in the upper gastrointestinal (GI) tract. Food effects may lead to changes of one or more pharmacokinetic parameters and, hence, influence drug plasma levels. This can result in severe consequences such as adverse drug reactions or even therapy failure. This review highlights different examples of drug performance under fed conditions. Various reasons such as delayed gastric emptying and pH-dependent solubility of the API as well as intragastric location and movement profiles of solid dosage forms can account for changed drug dissolution. Over the past years, several biorelevant media (e.g., fed state simulated gastric fluid) have been developed with the aim to approach the physiological situation regarding parameters such as pH, buffer capacity, surface tension, and osmolality. It was shown in different in vitro experiments that all of these factors can have an impact on drug dissolution. Besides the application of complex media such as milk or nutritional drinks, the dynamic changes of the gastric content were depicted in recent studies. The capabilities, limitations, and applicability of newly established test setups for the biorelevant simulation of intragastric drug delivery behavior are discussed. Simple test devices (e.g., rotating beaker or dissolution stress test) are mainly used for the biopharmaceutical evaluation of certain problems such as the impact of pressure or shear forces. On the other hand, complex biorelevant test devices (e.g., TNO TIM-1, Dynamic Gastric Model) have recently been introduced aiming at the simulation of multiple parameters characteristic for the postprandial upper GI tract. The different test methods are reviewed with respect to the spectrum of the simulated physiological factors and the degree of complexity. PMID:23654347

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

2013-06-01

6

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

7

Multidimensional column-switching liquid chromatographic method for dissolution testing of enprostil soft elastic gelatin capsules.  

PubMed

Enprostil (methyl 7-[(1 R,2R,3R)-3-hydroxy-2-[(E)-(3R)-3-hydroxy-4- phenoxy-1-butenyl]-5-oxocyclopentyl]-4,5-heptadienoate), an E-type prostaglandin exhibiting anti-ulcer activity, is formulated as a propylene carbonate solution filled into soft elastic gelatin (SEG) capsules. Enprostil SEG capsules were maintained for timed intervals at 50 degrees C, 30 degrees C, and room temperature, and the quantity of drug released upon complete capsule dissolution was determined as a function of storage condition. The dissolution test adhered to USP XXI guidelines (paddle method) and used a multidimensional HPLC technique to provide a sensitive and selective enprostil assay. Parallel HPLC assays determined the enprostil concentration in the propylene carbonate fill that was physically expressed from initially manufactured and from aged capsules. This corrected for any enprostil loss via chemical degradation on storage. The study included six different aged samples (six replicates each), and for all six samples, the enprostil recovered from dissolved capsules averaged 104 +/- 1.4% of the enprostil physically expressed from the capsules. Similarly, the enprostil recovered from dissolved, aged capsules averaged 103 +/- 5% of the enprostil physically expressed from capsules at the initial time point. These findings exclude the possibility that interactions with the SEG capsule wall reduce drug availability during storage under normal conditions. The multidimensional HPLC technique should generally extend to analysis of other noncationic drugs formulated into soft gelatin capsules. PMID:3098958

Kenley, R A; Chaudhry, S; Visor, G C

1986-10-01

8

Dissolution Testing as a Prognostic Tool for Oral Drug Absorption: Dissolution Behavior of Glibenclamide  

Microsoft Academic Search

Purpose. The dissolution behavior of two commercially availableglibenclamide formulations was tested in various media. The aim of thestudy was to investigate whether the use of biorelevant dissolutionmedia (BDM) would be advantageous over the use of standard mediafor predicting the in vivo performance of the two formulations.Methods. The dissolution tests were performed using USP 23 apparatus2. Conventional buffers and USP media

Raimar Löbenberg; Johannes Krämer; Vinod P. Shah; Gordon L. Amidon; Jennifer B. Dressman

2000-01-01

9

Studies on dissolution tests for soft gelatin capsules by the rotating dialysis cell (RDC) method. VI. Preparation and evaluation of ibuprofen soft gelatin capsule.  

PubMed

We prepared soft gelatin capsules (SC) containing ibuprofen (IB), a widely used phenylpropionic acid-derived antiphlogistic-analgesic drug. To evaluate the SC, in vitro dissolution tests were performed both by the paddle (PD) method described in the Japanese Pharmacopoeia (JPXII) and by the rotating dialysis cell (RDC) method which we previously developed and evaluated for application. In vivo, the blood IB concentration was determined after administration to beagles. Higher bioavailability was observed after administration of the SC containing IB than after administration of the bulk IB powder. A higher correlation was observed between the in vitro dissolution behavior and in vivo results by the RDC method than by the PD method, suggesting the usefulness of the RDC method in the dissolution test of SC. PMID:7553987

Takahashi, M; Yuasa, H; Kanaya, Y; Uchiyama, M

1995-08-01

10

Multivariate chemometric approach to fiber-optic dissolution testing.  

PubMed

The use of fiber optics in in vitro dissolution testing opens up new possibilities for more powerful data evaluation since an entire UV-Vis spectrum can be collected at each measuring point. This paper illustrates a multivariate chemometric approach to the solution of problems of interfering absorbance of excipients in in vitro dissolution testing. Two different chemometric approaches are tested: multivariate calibration using partial least squares (PLS) regression and curve resolution using multivariate curve resolution alternating least squares (MCR-ALS), generalized rank annihilation (GRAM), and parallel factor analysis (PARAFAC). Multivariate calibration (PLS) can, following the construction of a calibration model from a calibration sample set, give selective and accurate determinations of the active ingredient in dissolution testing despite the presence of interfering absorbance from excipients. Curve resolution (MCR-ALS, GRAM, or PARAFAC) can be applied to dissolution testing data in order to determine the dissolution rate profiles and spectra for the interfering excipients as well as for the active ingredient without any precalibration. The concept of the application of these chemometric methods to fiber-optic dissolution testing data is exemplified by analysis of glibenclamide tablets enclosed in hard gelatin capsules. The results show that, despite highly overlapping spectra and unresolved raw data, it is possible with PLS to obtain an accurate dissolution rate profile of glibenclamide. Applying curve resolution makes it possible to obtain accurate estimates of both dissolution rate profiles and spectra of both the gelatin capsule and the glibenclamide. The application of multivariate chemometric methods to fiber-optic dissolution testing brings a fresh scope for a deeper understanding of in vitro dissolution testing, solving the problem of interfering absorbance of excipients and making it possible to obtain dissolution rate profiles and spectra of these. Obtaining dissolution rate profiles of multiple active pharmaceutical ingredients in tablets consisting of several active compounds is another possibility. PMID:16841932

Wiberg, Kent H; Hultin, Ulla-Karin

2006-07-15

11

Dissolution test acceptance sampling plans.  

PubMed

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 a lot is accepted when the tablets or capsules sampled are accepted as proof of compliance with the requirement. In this paper, the operating characteristics of the USP acceptance rules are reviewed and compared to a selected modification. The operating characteristics curves show that the USP acceptance rules are sensitive to the true mean dissolution and do not reject a lot or batch that has a large percentage of tablets that dissolve with less than the dissolution specification. PMID:7581426

Tsong, Y; Hammerstrom, T; Lin, K; Ong, T E

1995-07-01

12

Hydrodynamic flows around tablets in different pharmacopeial dissolution tests.  

PubMed

We investigated the hydrodynamic flows around tablets during several pharmacopeial dissolution tests: the rotating basket (RB), paddle (PD), flow-through cell (FT), and disintegration (DI) tests. The determination of hydrodynamic flow was based on the dissolution rate of United States Pharmacopeial salicylic acid nondisintegrating calibrators, and showed that, compared with the PD and RB methods, the FT method produced a lower hydrodynamic flow value whereas the DI method produced a higher value. The hydrodynamic flows during the PD and RB tests appeared to be similar at the same rotational speed, although the flow patterns around the tablet differed; with the RB method, homogeneous dissolution occurred from all surfaces of the tablet, while with the PD method, dissolution from the lower surface was slower. The use of a sinker seemed to enhance dissolution from the lower surface. Such differences in hydrodynamic flow could explain the apparently different dissolution behaviors of disintegrating prednisone and nondisintegrating acetaminophen tablets when assessed by the PD and RB methods. These differences in hydrodynamic flow between in vitro tests should be considered when choosing dissolution tests for studying in vitro/in vivo relationships and for quality control purposes. PMID:12149957

Morihara, M; Aoyagi, N; Kaniwa, N; Katori, N; Kojim, S

2002-07-01

13

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

14

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

15

Dissolution testing for generic drugs: an FDA perspective.  

PubMed

In vitro dissolution testing is an important tool used for development and approval of generic dosage forms. The objective of this article is to summarize how dissolution testing is used for the approval of safe and effective generic drug products in the United States (US). Dissolution testing is routinely used for stability and quality control purposes for both oral and non-oral dosage forms. The dissolution method should be developed using an appropriate validated method depending on the dosage form. There are several ways in which dissolution testing plays a pivotal role in regulatory decision-making. It may be used to waive in vivo bioequivalence (BE) study requirements, as BE documentation for Scale Up and Post Approval Changes (SUPAC), and to predict the potential for a modified-release (MR) drug product to dose-dump if co-administered with alcoholic beverages. Thus, in vitro dissolution testing plays a major role in FDA's efforts to reduce the regulatory burden and unnecessary human studies in generic drug development without sacrificing the quality of the drug products. PMID:21479700

Anand, Om; Yu, Lawrence X; Conner, Dale P; Davit, Barbara M

2011-09-01

16

In situ dissolution testing using potentiometric sensors.  

PubMed

Potentiometric sensors can be used to determine the amount of API dissolved in the dissolution medium in function of time by measuring directly in the dissolution vessel of a Paddle (USP type 2) and Basket (USP type 1) apparatus. The prototype potentiometric sensor instrumentation showed very promising results for a selection of APIs with different physico-chemical properties. The applicability, benefits and limitations of the prototype were explored. The applicability of the measurement technique strongly depends on the log(P) of the API. Here, it is shown that measurements can easily be performed for APIs with a log(P)>4. Electrode performance however decreases with decreasing logP of the APIs due to decreased drug selectivity in comparison to the excipients and ionic strength of the applied dissolution medium. The potentiometric sensors are shown to be insensitive towards undissolved particles and air bubbles as opposed to UV spectrometric measurement where these can lead to severe light scattering. For the tested APIs, the obtained dissolution profiles are very reproducible and show a low variation compared to the measurements using manual sampling and UV or HPLC analysis. The measurements demonstrate that potentiometric sensors are a very promising technology that can become a standard for in situ dissolution measurements. PMID:18539443

Peeters, Karl; De Maesschalck, Roy; Bohets, Hugo; Vanhoutte, Koen; Nagels, Luc

2008-08-01

17

Commentary: Towards Physico-Relevant Dissolution Testing: The Importance of Solid-State Analysis in Dissolution  

Microsoft Academic Search

Polymorphism and other solid-state phenomena can have effects on many physicochemical properties of pharmaceuticals. In this commentary, some aspects of solid-state pharmaceutics that are important to dissolution testing are highlighted. Examples of how solid-state analysis can be used to aid interpretation of dissolution results are also reviewed. We suggest the term physico-relevant dissolution testing to describe the combination of dissolution

Jaakko Aaltonen; Thomas Rades

18

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

19

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

20

Dissolution testing of soft shell capsules-acetaminophen and nifedipine.  

PubMed

The problem of pelliculation of soft gelatin capsules on aging has been studied. Pelliculation frequently differs in soft shell capsules from hard shell capsules because of the larger mass of gelatin in the softshell dosage form. Two batches of nifedipine soft shell capsules are described. One batch failed in vivo testing and the other batch did not, after storage at 25 degrees C, yet both batches failed dissolution testing by the USP apparatus II method. The USP dissolution apparatus III-method, however, distinguished correctly between the batches. The study reported here was carried out with acetaminophen and was set up to establish whether the USP apparatus III testing method would be more suitable, and if so, what the most desirable dissolution medium should be. To create controlled pelliculation, samples were made with 0, 20, and 80 ppm of formaldehyde. The resulting capsules were subjected to ambient and accelerated storage and dissolution testing was carried out. It was found that the USP apparatus III method best reflected distinction between acceptable and substandard capsules. PMID:9294822

Bottom, C B; Clark, M; Carstensen, J T

1997-09-01

21

Effects of vessel geometric irregularity on dissolution test results.  

PubMed

Dissolution testing of pharmaceutical products is an important technique used extensively for both product development and quality control, but there are many variables that can affect dissolution results. In this study, the effect of the inner shape of standard 1-L dissolution vessels on drug dissolution results was investigated. The geometric dimensions and irregularities of commercially available vessels (obtained from four different manufacturers) were examined using a three-dimensional video-based measuring machine (VMM). The same analyst, dissolution test assembly, and experimental conditions were used for dissolution testing involving 10 mg of prednisone tablets (NCDA #2) with dissolution apparatus 2 (paddle). Mechanical calibration of the dissolution apparatus was performed prior to dissolution testing with each set of vessels. Geometric characteristics varied within and among the sets of vessels, but the overall averages and standard deviations of dissolution results (six vessels) showed no statistical significant differences among the vessel sets. However, some dissolution differences were noted when comparing individual vessels. With these types of comparisons, the vessel concentricity, sphericity, and radius of sphere were found to possibly influence the amount of prednisone dissolved, but flatness of vessel flange, cylindricity, and circularity showed no effect on dissolution results. The study shows that VMM is a technique that could be used to qualify dissolution vessels. PMID:20803604

Gao, Zongming; Ahadi, Shafiq; Moore, Terry W; Doub, William H; Westenberger, B J; Buhse, Lucinda F

2011-03-01

22

Transfer of drug dissolution testing by statistical approaches: Case study  

PubMed Central

The analytical transfer is a complete process that consists in transferring an analytical procedure from a sending laboratory to a receiving laboratory. After having experimentally demonstrated that also masters the procedure in order to avoid problems in the future. Method of transfers is now commonplace during the life cycle of analytical method in the pharmaceutical industry. No official guideline exists for a transfer methodology in pharmaceutical analysis and the regulatory word of transfer is more ambiguous than for validation. Therefore, in this study, Gauge repeatability and reproducibility (R&R) studies associated with other multivariate statistics appropriates were successfully applied for the transfer of the dissolution test of diclofenac sodium as a case study from a sending laboratory A (accredited laboratory) to a receiving laboratory B. The HPLC method for the determination of the percent release of diclofenac sodium in solid pharmaceutical forms (one is the discovered product and another generic) was validated using accuracy profile (total error) in the sender laboratory A. The results showed that the receiver laboratory B masters the test dissolution process, using the same HPLC analytical procedure developed in laboratory A. In conclusion, if the sender used the total error to validate its analytical method, dissolution test can be successfully transferred without mastering the analytical method validation by receiving laboratory B and the pharmaceutical analysis method state should be maintained to ensure the same reliable results in the receiving laboratory.

AL-Kamarany, Mohammed Amood; EL Karbane, Miloud; Ridouan, Khadija; Alanazi, Fars K.; Hubert, Philippe; Cherrah, Yahia; Bouklouze, Abdelaziz

2011-01-01

23

Transfer of drug dissolution testing by statistical approaches: Case study.  

PubMed

The analytical transfer is a complete process that consists in transferring an analytical procedure from a sending laboratory to a receiving laboratory. After having experimentally demonstrated that also masters the procedure in order to avoid problems in the future. Method of transfers is now commonplace during the life cycle of analytical method in the pharmaceutical industry. No official guideline exists for a transfer methodology in pharmaceutical analysis and the regulatory word of transfer is more ambiguous than for validation. Therefore, in this study, Gauge repeatability and reproducibility (R&R) studies associated with other multivariate statistics appropriates were successfully applied for the transfer of the dissolution test of diclofenac sodium as a case study from a sending laboratory A (accredited laboratory) to a receiving laboratory B. The HPLC method for the determination of the percent release of diclofenac sodium in solid pharmaceutical forms (one is the discovered product and another generic) was validated using accuracy profile (total error) in the sender laboratory A. The results showed that the receiver laboratory B masters the test dissolution process, using the same HPLC analytical procedure developed in laboratory A. In conclusion, if the sender used the total error to validate its analytical method, dissolution test can be successfully transferred without mastering the analytical method validation by receiving laboratory B and the pharmaceutical analysis method state should be maintained to ensure the same reliable results in the receiving laboratory. PMID:24109204

Al-Kamarany, Mohammed Amood; El Karbane, Miloud; Ridouan, Khadija; Alanazi, Fars K; Hubert, Philippe; Cherrah, Yahia; Bouklouze, Abdelaziz

2012-01-01

24

ACID DISSOLUTION METHOD FOR THE ANALYSIS OF PLUTONIUM IN SOIL: EVALUATION OF AN INTERLABORATORY COLLABORATIVE TEST AND COMPARISON WITH RESULTS OF A FUSION METHOD TEST  

EPA Science Inventory

The data from an interlaboratory collaborative test are presented. A statistical analysis of the data is also presented. From that analysis, statements are made of the combined within-laboratory precision, the systematic error between laboratories, the total error between laborat...

25

Calibration—The USP Dissolution Apparatus Suitability Test  

Microsoft Academic Search

This report summarizes some trends observed in drug dissolution testing, based upon the United States Pharmacopeia (USP) dissolution Apparatus Suitability Test results and the preliminary data obtained from an international collaborative study to assess the pharmaceutical quality of furosemide products in different countries. Based on the USP calibrator data submitted by the participants, representing four lots each of nondisintegrating (Salicylic

Saeed A. Qureshi

1996-01-01

26

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

27

Online monitoring of dissolution tests using dedicated potentiometric sensors in biorelevant media  

Microsoft Academic Search

The performance of the Ion-Selective Electrode (ISE) for in vitro dissolution testing using biorelevant media was evaluated in this study. In vitro dissolution was carried out using USP apparatus 2 (paddle method) with classical and with updated biorelevant media to simulate the pre- and postprandial states. The ISE was used as an analytical stand-alone system and in combination with a

Daniel Juenemann; Hugo Bohets; Mahir Ozdemir; Roy de Maesschalck; Koen Vanhoutte; Karl Peeters; Luc Nagels; Jennifer B. Dressman

2011-01-01

28

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

29

Pilot-scale tests of HEME and HEPA dissolution process  

SciTech Connect

A series of pilot-scale demonstration tests for the dissolution of High Efficiency Mist Eliminators (HEME`s) and High Efficiency Particulate Airfilters (HEPA) were performed on a 1/5th linear scale. These fiberglass filters are to be used in the Defense Waste Processing Facility (DWPF) to decontaminate the effluents from the off-gases generated during the feed preparation process and vitrification. When removed, these filters will be dissolved in the Decontamination Waste Treatment Tank (DWTT) using 5 wt% NaOH solution. The contaminated fiberglass is converted to an aqueous stream which will be transferred to the waste tanks. The filter metal structure will be rinsed with process water before its disposal as low-level solid waste. The pilot-scale study reported here successfully demonstrated a simple one step process using 5 wt% NaOH solution. The proposed process requires the installation of a new water spray ring with 30 nozzles. In addition to the reduced waste generated, the total process time is reduced to 48 hours only (66% saving in time). The pilot-scale tests clearly demonstrated that the dissolution process of HEMEs has two stages - chemical digestion of the filter and mechanical erosion of the digested filter. The digestion is achieved by a boiling 5 wt% caustic solutions, whereas the mechanical break down of the digested filter is successfully achieved by spraying process water on the digested filter. An alternate method of breaking down the digested filter by increased air sparging of the solution was found to be marginally successful are best. The pilot-scale tests also demonstrated that the products of dissolution are easily pumpable by a centrifugal pump.

Qureshi, Z.H.; Strege, D.K.

1994-06-01

30

Development and validation of dissolution test for ritonavir soft gelatin capsules based on in vivo data.  

PubMed

The purpose of the study was to develop and validate a dissolution procedure for ritonavir soft gelatin capsules (Norvir) based on in vivo data. Several conditions such as medium composition, pH, surfactant concentration and rotation speed were evaluated. The method was carried out using the same batch of Norvir used in a bioequivalence study and the in vivo data were used to select the best dissolution test conditions based on in vitro-in vivo correlation (IVIVC). The dissolution test was validated using a high-performance liquid chromatographic method (HPLC). For this formulation, the best dissolution conditions were achieved using paddle, 900ml of medium containing water with 0.7% (w/v) of sodium lauryl sulfate at a rotation speed of 25rpm. Under these conditions a significant linear relationship between fraction of ritonavir absorbed and dissolved was obtained (R(2)=0.993) and a level A IVIVC was established. In the HPLC method a relative standard deviation for intra-day precision was <1.6% and for inter-day precision was <1.4%. Accuracy was from 98.5% to 101.6% over the concentration range required for the dissolution test (4.0-124.0microg/ml). Both the HPLC method and the dissolution test are validated and could be used to evaluate the dissolution profile of ritonavir soft gelatin capsules. PMID:17343999

Rossi, Rochele C; Dias, Carolina L; Donato, Eliane M; Martins, Laura A; Bergold, Ana M; Fröehlich, Pedro E

2007-06-29

31

Studies of variability in dissolution testing with USP apparatus 2.  

PubMed

In this study, gauge repeatability and reproducibility (gauge R&R) was used to analyze variability for USP apparatus 2 dissolution measurement systems. Experiments were designed to assess the variability due to apparatus, operator, and sample tablet. Since dissolution testing is a destructive test, a nested model was used for data analysis. Additionally, perturbation tests with both disintegrating and nondisintegrating tablets were performed to study the variability due to sample position within the dissolution vessel. For the gauge R&R study, two well-trained chemists used two mechanically calibrated USP apparatus 2 units. Six tests were performed by each operator on each apparatus. Evaluation of dissolution test results at 30 min using an internal DPA calibrator tablet NCDA#2 (10 mg prednisone) indicates that the main contribution to the total variance, approximately 70%, is due to the sample tablets, approximately 25% is from the apparatus and approximately 5% is due to the operators. There is no significant difference between operators and apparatuses as shown by the gauge R&R studies. In addition, dissolution results can be strongly affected by the position of the tablet within the vessel. Similarity (f1) and dissimilarity (f2) factors were calculated to statistically evaluate differences between perturbed and normal dissolution tests. PMID:17252609

Gao, Zongming; Moore, Terry W; Smith, Anjanette P; Doub, William H; Westenberger, Benjamin J

2007-07-01

32

In vitro dissolution testing of drug-eluting stents.  

PubMed

Drug-eluting stents (DES) have revolutionized the treatment of coronary artery blockage by tremendously reducing the rate of in-stent restenosis and the necessity of repeat revascularization compared to bare-metal stents. They are also gaining increasing importance in other medical fields such as the treatment of certain localized tumors and in glaucoma therapy. DES generally contain most potent drugs, e.g. immunosuppressants or cytostatics, which are supposed to be released in a well controlled manner over time spans which are chosen according to disease progression. Typically, this means that fairly small amounts of drug are released over long periods of time. Therefore, quantification of in vivo plasma levels is often not feasible. Due to this limitation and the fact that tissue levels cannot be determined in humans, in vitro dissolution testing is one of the most powerful tools to gain insight into the release behaviour of DES. This article focuses on the methods for in vitro dissolution testing of DES which are available up to date and highlights the specific characteristics of drug release from stents arising from the composition and the in vivo localization of the dosage form. PMID:23092259

Seidlitz, Anne; Nagel, Stefan; Semmling, Beatrice; Sternberg, Katrin; Kroemer, Heyo K; Weitschies, Werner

2013-01-01

33

Development and Validation of New Discriminative Dissolution Method for Carvedilol Tablets  

PubMed Central

The objective of the present study was to develop and validate a discriminative dissolution method for evaluation of carvedilol tablets. Different conditions such as type of dissolution medium, volume of dissolution medium and rotation speed of paddle were evaluated. The best in vitro dissolution profile was obtained using Apparatus II (paddle), 50 rpm, 900 ml of pH 6.8 phosphate buffer as dissolution medium. The drug release was evaluated by high-performance liquid chromatographic method. The dissolution method was validated according to current ICH and FDA guidelines using parameters such as the specificity, accuracy, precision and stability were evaluated and obtained results were within the acceptable range. The comparison of the obtained dissolution profiles of three different products were investigated using ANOVA-based, model-dependent and model-independent methods, results showed that there is significant difference between the products. The dissolution test developed and validated was adequate for its higher discriminative capacity in differentiating the release characteristics of the products tested and could be applied for development and quality control of carvedilol tablets.

Raju, V.; Murthy, K. V. R.

2011-01-01

34

Validation of analytical methods involved in dissolution assays: acceptance limits and decision methodologies.  

PubMed

Dissolution tests are key elements to ensure continuing product quality and performance. The ultimate goal of these tests is to assure consistent product quality within a defined set of specification criteria. Validation of an analytical method aimed at assessing the dissolution profile of products or at verifying pharmacopoeias compliance should demonstrate that this analytical method is able to correctly declare two dissolution profiles as similar or drug products as compliant with respect to their specifications. It is essential to ensure that these analytical methods are fit for their purpose. Method validation is aimed at providing this guarantee. However, even in the ICHQ2 guideline there is no information explaining how to decide whether the method under validation is valid for its final purpose or not. Are the entire validation criterion needed to ensure that a Quality Control (QC) analytical method for dissolution test is valid? What acceptance limits should be set on these criteria? How to decide about method's validity? These are the questions that this work aims at answering. Focus is made to comply with the current implementation of the Quality by Design (QbD) principles in the pharmaceutical industry in order to allow to correctly defining the Analytical Target Profile (ATP) of analytical methods involved in dissolution tests. Analytical method validation is then the natural demonstration that the developed methods are fit for their intended purpose and is not any more the inconsiderate checklist validation approach still generally performed to complete the filing required to obtain product marketing authorization. PMID:23084050

Rozet, E; Ziemons, E; Marini, R D; Boulanger, B; Hubert, Ph

2012-11-01

35

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

36

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

PubMed

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 and the dissolution stress test apparatus. Investigated were Adalat OROS in strengths of 30 and 60 mg, and two hydrophilic matrix formulations: 60 mg nifedipine Coral and Nifedipin Sandoz 40 mg retard. The results demonstrate that the dissolution characteristic of the ER tablets is strongly dependent on the applied test conditions. The dosage form related food effects for Coral 60 mg tablets that were previously observed in human bioequivalence studies could be predicted with the two non-compendial dissolution test devices. The dissolution of Sandoz 40 mg tablets was very sensitive to all applied test conditions. The stable drug delivery characteristics of Adalat OROS observed in numerous in vivo studies was also observed in all of the dissolution tests. In conclusion, the present study shows that besides pH dependency the aspect of the mechanical robustness may be an essential factor affecting the dissolution characteristic of hydrogel matrix formulations. PMID:19591927

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

2009-09-10

37

An optical method for continuous monitoring of the dissolution rate of pharmaceutical powders.  

PubMed

Monitoring systems providing fast and reliable, even on-line data, from a distinct process stage or final product are needed in drug development, from the early stages of drug discovery until the drug product manufacturing procedures. This includes also processes involving solid particles, such as drug dissolution. However, the existing in vitro drug dissolution test methods suffer limitations, such as long sampling times of 30-60s and thus the inability to be adapted to continuous monitoring, time consuming sample preparation and consumption of large amounts of reagents. In this study, an optical method for monitoring the dissolution rate of pharmaceutical powders was evaluated with model drugs having different dissolution rates. The measuring system consisted of a laser source, light detector, oscilloscope, magnetic stirrer and sample vessel. The intensity of laser light transmitted through the dissolution medium was recorded and displayed by the oscilloscope. Dissolution curves were produced by fitting the raw data with mathematical functions. The optical method was found to be resource-saving, reliable and capable of detecting differences in even rapid dissolution rates of drug compounds. This technique might have targets of application in real-time monitoring of processes in many different sectors, including the pharmaceutical industry. PMID:20116958

Laitinen, Riikka; Lahtinen, Jani; Silfsten, Pertti; Vartiainen, Erik; Jarho, Pekka; Ketolainen, Jarkko

2010-06-01

38

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

39

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

40

Biorelevant in vitro dissolution testing of products containing micronized or nanosized fenofibrate with a view to predicting plasma profiles  

Microsoft Academic Search

The ability of in vitro biorelevant dissolution tests to predict the in vivo performance of nanosized fenofibrate (Lipidil 145 ONE®) and microsized fenofibrate (Lipidil – Ter®) was evaluated in this study. In vitro dissolution was carried out using USP apparatus 2 (paddle method) with updated biorelevant media to simulate the pre- and postprandial states. Membrane filters with different pore sizes

Daniel Juenemann; Ekarat Jantratid; Christian Wagner; Christos Reppas; Maria Vertzoni; Jennifer B. Dressman

2011-01-01

41

Engineering tools for understanding the hydrodynamics of dissolution tests.  

PubMed

In this article, three well-established engineering tools are used to examine hydrodynamics in dissolution testing apparatuses. The application of these tools would provide detailed information about the flow, shear, and homogeneity in dissolution tests. Particle image velocimetry successfully measures two-dimensional cross-sections of the velocity field in an experimental device under both laminar and turbulent conditions. The velocity field is also calculated with computational fluid dynamics (CFD), which can rapidly provide data that is difficult or impossible to obtain experimentally. The occurrence of segregated regions within a USP Apparatus II under mild agitation conditions is revealed by CFD simulations and confirmed by laser-induced fluorescence experiments. The results clearly demonstrate that under current operation settings, the USP Apparatus II operates in a regime where the flow is in incipient turbulence, which is a highly time-dependent condition that might explain possible inconsistencies in dissolution results. It is further demonstrated that proposed changes advocating lower speeds or smaller vessels displace the system toward laminar flow conditions characterized by segregation, compromising the robustness of the test and making it vulnerable to variability with respect to sample location. PMID:12648020

Kukura, Joseph; Arratia, Paulo E; Szalai, Edit S; Muzzio, Fernando J

2003-02-01

42

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

43

What is a Suitable Dissolution Method for Drug Nanoparticles?  

Microsoft Academic Search

Purpose  Many existing and new drugs fail to be fully utilized because of their limited bioavailability due to poor solubility in aqueous\\u000a media. Given the emerging importance of using nanoparticles as a promising way to enhance the dissolution rate of these drugs,\\u000a a method must be developed to adequately reflect the rate-change due to size reduction. At present, there is little

Desmond Heng; David J. Cutler; Hak-Kim Chan; Jimmy Yun; Judy A. Raper

2008-01-01

44

Dynamic Dissolution Testing To Establish In Vitro \\/ In Vivo Correlations for Montelukast Sodium, a Poorly Soluble Drug  

Microsoft Academic Search

Purpose  The objectives of the study was to develop a dissolution test method that can be used to predict the oral absorption of montelukast\\u000a sodium, and to establish an in vitro\\/in vivo correlation (IVIVC) using computer simulations.\\u000a \\u000a \\u000a \\u000a Methods  Drug solubility was measured in different media. The dissolution behaviour of montelukast sodium 10 mg film coated tablets\\u000a was studied using the flow-through cell dissolution

Arthur Okumu; Marie DiMaso; Raimar Löbenberg

2008-01-01

45

Designing biorelevant dissolution tests for lipid formulations: case example--lipid suspension of RZ-50.  

PubMed

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 the USP Apparatus 3 (Bio-Dis method). Pharmacokinetic data were obtained in dogs after oral administration of a single 2.5mg dose of RZ-50 soft gelatin capsules in the postprandial state. Level A IVIVC analysis and curve comparison of fraction drug dissolved vs. absorbed using the Weibull distribution were used to evaluate the in vitro methods in terms of their ability to fit the in vivo plasma profiles. Very low drug release was observed with the paddle method owing to poor dispersibility of the lipids in the dissolution media, whereas the Bio-Dis method hydrodynamics facilitated release of the drug by emulsifying the formulation in the medium. The best IVIVC was obtained using a dissolution medium representing fed gastric conditions in combination with the Bio-Dis method. Curve comparisons of the fraction drug absorbed and the fraction drug dissolved profiles based on Weibull distribution fits yielded similar results. The Bio-Dis/biorelevant in vitro method appears to be suitable for this type of lipid formulation. PMID:18226882

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

2008-06-01

46

[The dissolution test in biorelevant media as a prognostic tool for modeling of drug behavior in vivo].  

PubMed

The review deals with the modern tool for modeling of drug behavior in vivo, - the dissolution test in biorelevant media, imitating gastrointestinal fluids. The formulations and preparation methods of fasted state simulation intestinal fluid, FaSSIF and fed state simulation intestinal fluid, FeSSIF, are defined. In addition, the dissolution characteristics of APIs from different BCS classes in biorelevant media are described. Possible applications of biorelevant media in regulatory practice and science are also shown. PMID:22629598

Ramenskaia, G V; Shokhin, I E; Savchenko, A Iu; Volkova, E A

2011-01-01

47

Gauge repeatability and reproducibility for accessing variability during dissolution testing: A technical note  

Microsoft Academic Search

Conclusions  In this study, the gauge R&R method was used to analyze sources of variability for the paddle apparatus (USP apparatus 2).\\u000a An initial evaluation of gauge R&R dissolution testing results using the amount dissolved at 30 minutes for a 10-mg prednisone\\u000a tablet showed no instrument or operator contributions to variability but did highlight some vessel differences within an instrument.\\u000a Based

Zongming Gao; Terry Moore; Anjanette P. Smith; William Doub; Benjamin Westenberger; Lucinda Buhse

2007-01-01

48

Screening method to identify preclinical liquid and semi-solid formulations for low solubility compounds: miniaturization and automation of solvent casting and dissolution testing.  

PubMed

We have developed an efficient screening method to identify liquid and semisolid formulations for low-solubility compounds. The method is most suitable for identifying dosing vehicles for compounds in lead optimization, where compound supply is limited and long-term stability is not a requirement. Dilute compound and excipient stock solutions are prepared in organic solvent and then dispensed and mixed in 96-well plates. The solvent is removed in a vacuum centrifuge evaporator, leaving neat formulation (e.g., 10-40 microg compound, 0.4 mg excipient) at the bottom of each well. After an aging step, an aqueous dilution medium is added and the plates are incubated (agitation by orbital shaking). The diluted formulations are then filtered and analyzed by ultraviolet (UV) absorbance or high-performance liquid chromatography (HPLC). To illustrate the method, two compounds (aqueous solubility method to screening compound/surfactant/oil formulations is also presented. PMID:17094139

Mansky, Paul; Dai, Wei-Guo; Li, Shu; Pollock-Dove, Crystal; Daehne, Klaus; Dong, Liang; Eichenbaum, Gary

2007-06-01

49

K Basin Sludge Conditioning Testing: Nitric Acid Dissolution Testing of K East Canister Sludge  

Microsoft Academic Search

This report describes tests performed by Pacific Northwest National Laboratory (PNNL) for Numatec Hanford Corporation (NHC) as part of the overall activities for the development of the K Basin Sludge Treatment System. These tests were conducted to examine the dissolution behavior of a K East Basin canister sludge composite in nitric acid at the following concentrations: 2 M, 4 M,

C. D. Carlson; C. H. Delegard; Burgeson; P. R. Bredt; K. L. Silvers

1999-01-01

50

K Basin Sludge Conditioning Testing: Nitric Acid Dissolution Testing of K East Canister Sludge  

SciTech Connect

This report describes tests performed by Pacific Northwest National Laboratory (PNNL) for Numatec Hanford Corporation (NHC) as part of the overall activities for the development of the K Basin Sludge Treatment System. These tests were conducted to examine the dissolution behavior of a K East Basin canister sludge composite in nitric acid at the following concentrations: 2 M, 4 M, 6 M, 7.8 M and 10 M and temperatures of 25 C and boiling. Assuming that the sludge was 100% uranium metal, a 4X stoichiometric excess of nitric acid was used for all testing, except that conducted at 4 M. In the 4 M nitric acid dissolution test, 50% excess nitric acid was used resulting in a dissolver solution with a significantly higher solids loading. The boiling tests were conducted for 11 hr, the 25 C dissolution tests were conducted from 24 hr to 2 weeks. For the 25 C dissolution testing, the weight percent residual solids was determined, however, chemical and radiochemical analyses were not performed.

Carlson, C.D.; Delegard, C.H.; Burgeson, I.E.: Schmidt, A.J.; Bredt, P.R.; Silvers, K.L.

1999-04-01

51

Development of Discriminating Method for Dissolution of Aceclofenac Marketed Formulations  

Microsoft Academic Search

The development of a meaningful dissolution procedure for drug products with limited water solubility has been a challenge to the pharmaceutical industry. Aceclofenac (BCS Class II drug) is a nonsteroidal anti-inflammatory drug. There is no official dissolution medium available in the literature. In the present study, parameters such as solubility, medium pH, surfactant type, dissolution behavior of formulations, influence of

Tejal Soni; Chirag Nagda; Tejal Gandhi; N. P. Chotai

52

Dating of black gel pen ink using the dissolution-diffusion method.  

PubMed

In many criminal and civil cases in China, the most commonly questioned documents are those written with gel pen ink. An important task for forensic document examiners is to identify whether two or more ink entries in one or more documents were written with the same ink type. The identification of the age of gel ink entries made poses an important and difficult problem for forensic document examiners. In this paper, a dissolution-diffusion method was successfully employed to estimate the relative age of gel ink entries by comparing dissolution-diffusion rates. Using extensive tests, the mixed solution of dimethyl formamide (DMF) and anhydrous ethanol proved to be a suitable solvent and was used to dissolve the dye of gel ink strokes made at different times. As preliminary findings of this study, calibration curves were created to indicate the relationship between the average dissolution-diffusion rate of soluble gel ink components and the age of gel ink entries stored under natural aging conditions. It was also determined that brands of gel inks, types of paper and thickness of gel ink strokes had varying impacts on estimating the dates of gel ink strokes. Experimental results showed that dissolution-diffusion method was applicable for determining the relative age of gel ink entries under certain conditions. PMID:24378312

Li, Biao

2014-01-01

53

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

2010-10-01

54

21 CFR 343.90 - Dissolution and drug release testing.  

Code of Federal Regulations, 2013 CFR

...USP 23 at page 134. (e) Aspirin, alumina, and magnesia tablets. Aspirin in combination with alumina and magnesia in a tablet dosage form must...the dissolution standard for aspirin, alumina, and magnesia tablets as contained...

2013-04-01

55

Development of a two-step tier-2 dissolution method for blinded overencapsulated erlotinib tablets using UV fiber optic detection.  

PubMed

Measuring dissolution of a comparator drug overencapsulated in a hard gelatin shell is necessary when determining performance of the native and blinded formulations. However, the gelatin in the shell may form cross-links upon storage at stressed conditions, resulting in slow dissolution of the encapsulated drug. The aim of this study was to develop a dissolution approach for a hard-gelatin overencapsulated formulation of a comparator drug, erlotinib, which can overcome cross linking of the capsule shell. In this case, following the USP two-tier dissolution test by simply adding an enzyme did not dissolve the cross-linked capsules because the medium used in the method for erlotinib described in the FDA Dissolution Database contains sodium dodecyl sulfate that inhibits the activity of the enzyme. Changing the method by using different surfactants was not considered acceptable because it is preferable to closely follow the compendial method for the comparator. A two-step tier-2 method was developed as a solution, without significant change to the compendial method conditions. It uses 0.1N HCl + pepsin as the initial medium to help capsule break-up. SDS is added at 15 min after the testing starts to ensure dissolution of the drug. This may be a useful general approach for dealing with cross-linking in over-encapsulated comparators. A UV fiber optic spectrophotometer was used for in situ, real-time detection of the dissolution profile during method development studies. The fast sampling rate available with this type of detection was important in elucidating the events occurring during dissolution and determining the optimal time of the SDS addition. PMID:21620602

Lu, Xujin; Xiao, Baiming; Lo, Lili; Bolgar, Mark S; Lloyd, David K

2011-08-25

56

Typical variability in drug dissolution testing: study with USP and FDA calibrator tablets and a marketed drug (glibenclamide) product  

Microsoft Academic Search

To evaluate variability in drug dissolution testing 28 laboratories analyzed USP calibrators, US FDA prednisone tablets and a marketed glibenclamide tablet product. The experiments were conducted using paddle and basket methods at 50 (calibrators) and 75 (glibenclamide) rpm. The media employed were deaerated by equilibrating at 37°C for 24 h and by the USP recommended method. The 95% CI values

Saeed A Qureshi; Iain J McGilveray

1999-01-01

57

A new method for alkaline dissolution of uranium metal foil  

Microsoft Academic Search

In order to develop a production process of 99Mo by fission of low-enriched uranium, the first purification step, which consists of dissolution of a uranium metal foil target, was studied. It was found that alkaline NaClO gave good results, reaching the dissolution of up to 300 m of uranium foil. The different conditions for the dissolution were studied and the

A. V. Mondino; M. V. Wilkinson; A. C. Manzini

2001-01-01

58

Discriminatory dissolution method for quality control measurements of carbamazepine immediate release tablets based on in vitro--in vivo investigations.  

PubMed

The purpose of this study was to identify a discriminatory dissolution method able to predict the in vivo performance of tablet formulations designed for carbamazepine (CBZ). After evaluation of dissolution medium and rotation speed using a 2? central composite design and investigation of the in vivo release behaviors in beagle dogs, the dissolution method of CBZ 100?mg tablets was validated using a USP apparatus II, at a rotation speed of 75?rpm, and 900?ml deaerated water with 0.5% sodium lauryl sulfate (w/v) as the dissolution medium. Dissolution profiles were evaluated by the Weibull parameters and the modified fit factor, ƒ^(1,area). The in vitro-in vivo relationship of CBZ tablets was examined. Compared with the results from the USP and Chinese Pharmacopoeia monograph, the proposed system provides a superior discriminatory method. Since the dissolution method in pharmacopoeia for CBZ tablets is unable to distinguish between a good and a bad product, the method presented here can be used for the quality control testing of CBZ tablets. PMID:21988132

Xu, Caihong; Zou, Meijuan; Wang, Yiping; Liu, Yi; Yan, Jing; Wu, Yi; Cheng, Gang

2012-06-01

59

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

60

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

National Technical Information Service (NTIS)

The work described in this report involved comprehensive bench-scale testing of nitric acid (HNOs) dissolution of actual sludge materials from the Hanford K East (KE) Basin to confirm the baseline chemical pretreatment process. In addition, process monito...

A. J. Schmidt C. H. Delegard K. L. Silvers C. D. Carlson

1999-01-01

61

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

62

Development and Validation of a Discriminating In Vitro Dissolution Method for a Poorly Soluble Drug, Olmesartan Medoxomil: Comparison Between Commercial Tablets  

PubMed Central

A dissolution test for tablets containing 40 mg of olmesartan medoxomil (OLM) was developed and validated using both LC-UV and UV methods. After evaluation of the sink condition, dissolution medium, and stability of the drug, the method was validated using USP apparatus 2, 50 rpm rotation speed, and 900 ml of deaerated H2O + 0.5% sodium lauryl sulfate (w/v) at pH?6.8 (adjusted with 18% phosphoric acid) as the dissolution medium. The model-independent method using difference factor (f1) and similarity factor (f2), model-dependent method, and dissolution efficiency were employed to compare dissolution profiles. The kinetic parameters of drug release were also investigated. The obtained results provided adequate dissolution profiles. The developed dissolution test was validated according to international guidelines. Since there is no monograph for this drug in tablets, the dissolution method presented here can be used as a quality control test for OLM in this dosage form, especially in a batch to batch evaluation.

Rossi, Rochele Cassanta; Dias, Carolina Lupi; Bergold, Ana Maria; Froehlich, Pedro Eduardo

2010-01-01

63

Development of Dissolution Tests for the Quality Control of Complementary\\/Alternate and Traditional Medicines: Application to African Potato Products  

Microsoft Academic Search

PURPOSE. Unlike orthodox medicines, specific guidelines for dissolution testing of complementary\\/alternate (CAMs) and traditional medicines (TMs) have not been developed nor is dissolution testing a requirement for the quality control of such products. In this report, the dissolution of African Potato (AP) products, an African traditional medicine (ATM) which has been ingested by man for a diversity of ailments, has

Vipin Devi Prasad Nair; Isadore Kanfer

2008-01-01

64

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

65

Silymarin-solid dispersions: characterization and influence of preparation methods on dissolution.  

PubMed

The influence of preparation methodology of silymarin solid dispersions using a hydrophilic polymer on the dissolution performance of silymarin was investigated. Silymarin solid dispersions were prepared using HPMC E 15LV by kneading, spray drying and co-precipitation methods and characterized by FTIR, DSC, XRPD and SEM. Dissolution profiles were compared by statistical and model independent methods. The FTIR and DSC studies revealed weak hydrogen bond formation between the drug and polymer, while XRPD and SEM confirmed the amorphous nature of the drug in co-precipitated solid dispersion. Enhanced dissolution compared to pure drug was found in the following order: co-precipitation > spray drying > kneading methodology (p < 0.05). All preparation methods enhanced silymarin dissolution from solid dispersions of different characteristics. The co-precipitation method proved to be best and provided a stable amorphous solid dispersion with 2.5 improved dissolution compared to the pure drug. PMID:21169135

Sonali, Dalwadi; Tejal, Soni; Vaishali, Thakkar; Tejal, Gandhi

2010-12-01

66

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

67

Permutation Test (PT) and Tolerated Difference Test (TDT): two new, robust and powerful nonparametric tests for statistical comparison of dissolution profiles.  

PubMed

The most popular way of comparing oral solid forms of drug formulations from different batches or manufacturers is through dissolution profile comparison. Usually, a similarity factor known as (f2) is employed; However, the level of confidence associated with this method is uncertain and its statistical power is low. In addition, f2 lacks the flexibility needed to perform in special scenarios. In this study two new statistical tests based on nonparametrical Permutation Test theory are described, the Permutation Test (PT), which is very restrictive to confer similarity, and the Tolerated Difference Test (TDT), which has flexible restrictedness to confer similarity, are described and compared to f2. The statistical power and robustness of the tests were analyzed by simulation using the Higuchi, Korsmayer, Peppas and Weibull dissolution models. Several batches of oral solid forms were simulated while varying the velocity of dissolution (from 30 min to 300 min to dissolve 85% of the total content) and the variability within each batch (CV 2-30%). For levels of variability below 10% the new tests exhibited better statistical power than f2 and equal or better robustness than f2. TDT can also be modified to distinguish different levels of similarity and can be employed to obtain customized comparisons for specific drugs. In conclusion, two new methods, more versatile and with a stronger statistical basis than f2, are described and proposed as viable alternatives to that method. Additionally, an optimized time sampling strategy and an experimental design-driven strategy for performing dissolution profile comparisons are described. PMID:23194886

Gómez-Mantilla, José-David; Casabó, Vicente Germán; Schaefer, Ulrich F; Lehr, Claus-Michael

2013-01-30

68

EVALUATION OF ARG-1 SAMPLES PREPARED BY CESIUM CARBONATE DISSOLUTION DURING THE ISOLOK SME ACCEPTABILITY TESTING  

SciTech Connect

Evaluation of Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) recently completed the evaluation of one of these opportunities - the possibility of using an Isolok sampling valve as an alternative to the Hydragard valve for taking DWPF process samples at the Slurry Mix Evaporator (SME). The use of an Isolok for SME sampling has the potential to improve operability, reduce maintenance time, and decrease CPC cycle time. The SME acceptability testing for the Isolok was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 and was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNLRP-2011-00145. RW-0333P QA requirements applied to the task, and the results from the investigation were documented in SRNL-STI-2011-00693. Measurement of the chemical composition of study samples was a critical component of the SME acceptability testing of the Isolok. A sampling and analytical plan supported the investigation with the analytical plan directing that the study samples be prepared by a cesium carbonate (Cs{sub 2}CO{sub 3}) fusion dissolution method and analyzed by Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES). The use of the cesium carbonate preparation method for the Isolok testing provided an opportunity for an additional assessment of this dissolution method, which is being investigated as a potential replacement for the two methods (i.e., sodium peroxide fusion and mixed acid dissolution) that have been used at the DWPF for the analysis of SME samples. Earlier testing of the Cs{sub 2}CO{sub 3} method yielded promising results which led to a TTR from Savannah River Remediation, LLC (SRR) to SRNL for additional support and an associated TTQAP to direct the SRNL efforts. A technical report resulting from this work was issued that recommended that the mixed acid method be replaced by the Cs{sub 2}CO{sub 3} method for the measurement of magnesium (Mg), sodium (Na), and zirconium (Zr) with additional testing of the method by DWPF Laboratory being needed before further implementation of the Cs{sub 2}CO{sub 3} method at that laboratory. While the SME acceptability testing of the Isolok does not address any of the open issues remaining after the publication of the recommendation for the replacement of the mixed acid method by the Cs{sub 2}CO{sub 3} method (since those issues are to be addressed by the DWPF Laboratory), the Cs{sub 2}CO{sub 3} testing associated with the Isolok testing does provide additional insight into the performance of the method as conducted by SRNL. The performance is to be investigated by looking to the composition measurement data generated by the samples of a standard glass, the Analytical Reference Glass - 1 (ARG-1), that were prepared by the Cs{sub 2}CO{sub 3} method and included in the SME acceptability testing of the Isolok. The measurements of these samples were presented as part of the study results, but no statistical analysis of these measurements was conducted as part of those results. It is the purpose of this report to provide that analysis, which was supported using JMP Version 7.0.2.

Edwards, T.; Hera, K.; Coleman, C.

2011-12-05

69

Online monitoring of dissolution tests using dedicated potentiometric sensors in biorelevant media.  

PubMed

The performance of the Ion-Selective Electrode (ISE) for in vitro dissolution testing using biorelevant media was evaluated in this study. In vitro dissolution was carried out using USP apparatus 2 (paddle method) with classical and with updated biorelevant media to simulate the pre- and postprandial states. The ISE was used as an analytical stand-alone system and in combination with a single-point HPLC-UV measurement. A modified method enabling the use of the ISE for very poorly soluble substances is also proposed. In terms of f(2)-factor, the results acquired using the ISE for the drug diphenhydramine-HCl were found to be very similar to the results obtained by manual sampling followed by HPLC-UV analysis. In Fed State Simulated Gastric Fluid (FeSSGF), a medium containing 50% milk, the ISE is more practical since the need to separate proteins from the analyte prior to HPLC-UV analysis is eliminated. Further work will be needed to establish ISE methodology for Fed State Simulated Intestinal Fluid (FeSSIF) media. In summary, the ISE has promise as an analytical tool for research and development applications. PMID:21168489

Juenemann, Daniel; Bohets, Hugo; Ozdemir, Mahir; de Maesschalck, Roy; Vanhoutte, Koen; Peeters, Karl; Nagels, Luc; Dressman, Jennifer B

2011-05-01

70

A simple method for dissolution of tantalum pentoxide.  

PubMed

A simple and reproducible procedure has been developed for the dissolution of tantalum pentoxide. The oxide is fused with potassium nitrate and potassium carbonate in the ratio of 2:5:5. The cooled melt is dissolved in concentrated sulphuric acid. If a tartaric acid solution is desired the sulphuric acid is evaporated and the residue dissolved in 20% tartaric acid solution. PMID:18962247

Qureshi, M; Rathore, H S; Thakur, J S

1978-04-01

71

A liquid chromatography method for quantifying caffeine dissolution from pharmaceutical formulations into colloidal, fat-rich media.  

PubMed

A simple and rapid high-performance liquid-chromatography method is presented that permits quantification of caffeine in colloidal fat emulsions proposed as new 'biorelevant' dissolution media (Intralipid and various milks). Using a mobile phase of 0.1 M sodium acetate (pH 4.0) and acetonitrile (89.5:10.5, v/v) at 1 ml min(-1), the drug and internal standard (7-beta-hydroxyethyltheophylline) were eluted within 8 min. Caffeine extraction was undertaken by protein precipitation in ice-cold 12% (w/v) trichloroacetic acid and centrifugation at 10,000 rpm for 15 min. This simple extraction method generated caffeine recovery values (corrected for % fat content) of 75.4+/-1.4-100.6+/-5.5%. The limit of detection was within the range 0.25-0.4 microg ml(-1) and linearity was demonstrated in each medium up to 125 microg ml(-1). Precision was <11.5% RSD and intra- and inter-day accuracy was 93.4-109.3%. The validated method was applied to in vitro USP dissolution tests in milk which compared the kinetics of caffeine release from (i) extended release matrices containing hydroxypropyl methylcellulose (HPMC) and (ii) an immediate release commercial analgesic tablet. Good reproducibility was obtained in both extended and immediate release dissolution tests. The method provides high-throughput quantification of this common drug in fat emulsions used as biorelevant dissolution media. PMID:20483672

Williams, Hywel D; Barrett, David A; Ward, Robert; Hardy, Ian J; Melia, Colin D

2010-07-01

72

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

Microsoft Academic Search

The work described in this report involved comprehensive bench-scale testing of nitric acid (HNO) 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

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

1999-01-01

73

Reactive tracer tests to predict dense nonaqueous phase liquid dissolution dynamics in laboratory flow chambers.  

PubMed

Reactive tracer tests were conducted to evaluate the relationship between contaminant mass reduction, Rm, and flux reduction, Rj, in laboratory experiments with porous media contaminated with a dense nonaqueous phase liquid (DNAPL). The reduction in groundwater contaminant flux resulting from partial mass removal was obtained from continuous and pulsed cosolvent and surfactant flushing dissolution tests in laboratory flow chambers packed with heterogeneous porous media. Using the streamtubes concept a Lagrangian analytical solution was applied to study the contaminant dissolution. The analytical solution was independently parametrized using nonreactive and reactive tracertests and the predicted dissolution was compared to the observed data. Analytical solution parameters related to aquifer hydrodynamic heterogeneities were determined from a nonreactive tracer, while those related to DNAPL spatial distribution heterogeneity were obtained from a reactive tracer. Reactive travel time variance, derived from this combination of tracers, was used to predict the relationship between Rm and Rj. Predictions based on the tracer tests closely matched measured dissolution data, suggesting that tracers can be used to characterize the DNAPL spatial distribution heterogeneity controlling the dissolution behavior. Experimental results demonstrated that increased reactive travel time variance led to greater flux reduction for a given partial mass removal. PMID:18754382

Chen, X; Jawitz, J W

2008-07-15

74

Facts, fallacies and future of dissolution testing of polysaccharide based colon-specific drug delivery.  

PubMed

Colonic diseases like ulcerative colitis, Crohn's disease, and colon cancer are on rise due to variations in the dietary and lifestyle habits. Increase in prevalence of such diseases has augmented the interest of researchers in colon targeted drug delivery systems. Polysaccharide coating has emerged as one of the most successful approaches in this direction. Evaluation of such systems, however, demands an efficient dissolution method in terms of convenience, economy, relevance and reproducibility. It is problematic to mimic the dynamic and ecologically diverse features of the colon. A number of dissolution approaches were tried which include incorporation of polysaccharide-degrading enzymes, rat caecal contents, human faecal slurries, and multi-stage culture systems. Till date, pursuit for cost-effective and animal-sparing colon-specific bio-relevant dissolution media has been a foremost challenge facing pharmaceutical scientists over many decades. This article reviews various dissolution methods adopted to mimic the in vivo performance of dosage forms that are used for colon targeting. It also highlights limitations of the available methods and conditions that should be taken into account while designing a bio-relevant dissolution method for such systems. PMID:24440665

Kotla, Niranjan Goud; Gulati, Monica; Singh, Sachin Kumar; Shivapooja, Ashwini

2014-03-28

75

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

76

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

77

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

78

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

79

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

National Technical Information Service (NTIS)

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 ...

A. J. Schmidt C. H. Delegard K. L. Silvers P. R. Bredt C. D. Carlson E. W. Hoppe J. C. Hayes D. E. Rinehart S. R. Gano B. M. Thornton

1999-01-01

80

Study of the deposition process of eggshell pigments using an improved dissolution method.  

PubMed

An improved dissolution method called layer-by-layer dissolution was adopted to study the process of eggshell deposition, which is opposite to the process of eggshell dissolution. In the present study, blue and brown eggshells from 2 Chinese indigenous chicken breeds, Dongxing and Shouguang, respectively, were analyzed with layer-by-layer dissolution. The results showed that the deposition velocity of the eggshell pigments in the top (first) eggshell layer was the highest compared with other layers, which were biliverdin and protoporphyrin in blue eggshell or primarily protoporphyrin in brown eggshell. It was also revealed that the deposition processes of biliverdin and protoporphyrin were synchronous in the blue eggshell of the Dongxiang chicken in the present study. PMID:17878455

Wang, X-T; Deng, X-M; Zhao, C-J; Li, J-Y; Xu, G-Y; Lian, L-S; Wu, C-X

2007-10-01

81

Physicochemical Properties and Dissolution Studies of Dexamethasone Acetate-?-Cyclodextrin Inclusion Complexes Produced by Different Methods  

PubMed Central

Inclusion complexes between dexamethasone acetate (DMA), a poorly water soluble drug, and ?-cyclodextrin (?CD) were obtained to improve the solubility and dissolution rate of this drug. Phase-solubility profile indicated that the solubility of DMA was significantly increased in the presence of ?CD (33-fold) and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Solid complexes prepared by different methods (kneading, coevaporation, freeze drying) and physical mixture were characterized by differential scanning calorimetry, thermogravimetry, infrared absorption and optical microscopy. Preparation methods influenced the physicochemical properties of the products. The dissolution profiles of solid complexes were determined and compared with those DMA alone and their physical mixture, in three different mediums: simulated gastric fluid (pH 1.2), simulated intestinal fluid (pH 7.4) and distilled water. The dissolution studies showed that in all mediums DMA presented an incomplete dissolution even in four hours. In contrast, the complexes formed presented a higher dissolution rate in simulated gastric fluid (SGF pH 1.2), which indicate that these have different ionization characteristics. According to the results, the freeze–dried and kneaded products exhibited higher dissolution rates than the drug alone, in all the mediums.

Doile, Mayara M.; Fortunato, Keila A.; Schmucker, Iara C.; Schucko, Sacha K.; Silva, Marcos A.S.

2008-01-01

82

Turbine blade testing methods  

NASA Technical Reports Server (NTRS)

Testing procedures which could be used to model test turbine blades are developed. The methods studied were methods which used and extended current modal testing procedures. An acoustical impacting testing method was perfected for testing small turbine blades.

1984-01-01

83

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

84

Development and Validation of a Discriminative Dissolution Test for Nimesulide Suspensions  

Microsoft Academic Search

The dissolution test for oral dosage forms has recently widened to a variety of special dosage forms such as suspensions.\\u000a For class II drugs, such as nimesulide (NMS), this study is very important because formulation problems may compromise drug\\u000a bioavailability. In the present work, tests with four brands of commercially available NMS (RA, TS, TB, and TC) have been\\u000a performed

Laís Bastos da Fonseca; Márcio Labastie; Valéria Pereira de Sousa; Nadia Maria Volpato

2009-01-01

85

Hydrodynamics-induced variability in the USP apparatus II dissolution test.  

PubMed

The USP tablet dissolution test is an analytical tool used for the verification of drug release processes and formulation selection within the pharmaceutical industry. Given the strong impact of this test, it is surprising that operating conditions and testing devices have been selected empirically. In fact, the flow phenomena in the USP test have received little attention in the past. An examination of the hydrodynamics in the USP apparatus II shows that the device is highly vulnerable to mixing problems that can affect testing performance and consistency. Experimental and computational techniques reveal that the flow field within the device is not uniform, and dissolution results can vary dramatically with the position of the tablet within the vessel. Specifically, computations predict sharp variations in the shear along the bottom of the vessel where the tablet is most likely to settle. Experiments in which the tablet location was carefully controlled reveal that the variation of shear within the testing device can affect the measured dissolution rate. PMID:15725550

Baxter, Jennifer L; Kukura, Joseph; Muzzio, Fernando J

2005-03-23

86

Hydroxyapatite, fluor-hydroxyapatite and fluorapatite produced via the sol-gel method: dissolution behaviour and biological properties after crystallisation.  

PubMed

Hydroxyapatite (HA), fluor-hydroxyapatite (FHA) with varying levels of fluoride ion substitution and fluorapatite (FA) were synthesised by the sol-gel method as possible implant coating or bone-grafting materials. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride were incorporated for the preparation of the FHA and FA sol-gels. After heating and powdering the sol-gels, dissolution behaviour was assessed using ion chromatography to measure Ca(2+) and PO4 (3-) ion release. Biological behaviour was assessed using cellular proliferation with human osteosarcoma cells and alamarBlue™ assay. Statistical analysis was performed with a two way analysis of variance and post hoc testing with a Bonferroni correction. Increasing fluoride substitution into an apatite structure decreased the dissolution rate. Increasing the firing temperature of the HA, FHA and FA sol-gels up to 1,000 °C decreased the dissolution rate. There was significantly higher cellular proliferation on highly substituted FHA and FA than on HA or Titanium. The properties of an implant coating or bone grafting material can be tailored to meet specific requirements by altering the amount of fluoride that is incorporated into the original apatite structure. The dissolution behaviour can further be altered by the temperature at which the sol-gel is fired. PMID:24052344

Tredwin, Christopher J; Young, Anne M; Abou Neel, Ensanya A; Georgiou, George; Knowles, Jonathan C

2014-01-01

87

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

88

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

89

In Vitro Dissolution Methods for Hydrophilic and Hydrophobic Porous Silicon Microparticles  

PubMed Central

Porous silicon (PSi) is an innovative inorganic material that has been recently developed for various drug delivery systems. For example, hydrophilic and hydrophobic PSi microparticles have been utilized to improve the dissolution rate of poorly soluble drugs and to sustain peptide delivery. Previously, the well-plate method has been demonstrated to be a suitable in vitro dissolution method for hydrophilic PSi particles but it was not applicable to poorly wetting hydrophobic thermally hydrocarbonized PSi (THCPSi) particles. In this work, three different in vitro dissolution techniques, namely centrifuge, USP Apparatus 1 (basket) and well-plate methods were compared by using hydrophilic thermally carbonized PSi (TCPSi) microparticles loaded with poorly soluble ibuprofen or freely soluble antipyrine. All the methods showed a fast and complete or nearly complete release of both model compounds from the TCPSi microparticles indicating that all methods described in vitro dissolution equally. Based on these results, the centrifuge method was chosen to study the release of a peptide (ghrelin antagonist) from the THCPSi microparticles since it requires small sample amounts and achieves good particle suspendability. Sustained peptide release from the THCPSi microparticles was observed, which is in agreement with an earlier in vivo study. In conclusion, the centrifuge method was demonstrated to be a suitable tool for the evaluation of drug release from hydrophobic THCPSi particles, and the sustained peptide release from THCPSi microparticles was detected.

Monkare, Juha; Riikonen, Joakim; Rauma, Elina; Salonen, Jarno; Lehto, Vesa-Pekka; Jarvinen, Kristiina

2011-01-01

90

Production and dissolution of nuclear explosive melt glasses at underground test sites in the Pacific Region  

SciTech Connect

From 1975 to 1996 the French detonated 140 underground nuclear explosions beneath the atolls of Mururoa and Fangataufa in the South Pacific; from 1965 to 1971 the United States detonated three high yield nuclear tests beneath Amchitka Island in the Aleutian chain. Approximately 800 metric tons of basalt is melted per kiloton of nuclear yield; almost lo7 metric tons of basalt were melted in these tests. Long-lived and toxic radionuclides are partitioned into the melt glass at the time of explosion and are released by dissolution with seawater under saturated conditions. A glass dissolution model predicts that nuclear melt glasses at these sites will dissolve in lo6 to lo7 yea

Bourcier, W.L.; Smith, D.K.

1998-11-06

91

Multiple fiber-optic dual-beam UV/Vis system with application to dissolution testing.  

PubMed

A system for fiber-optic probing in dissolution testing of solid pharmaceutical formulations has been constructed. The system is based on an imaging spectrometer and a charged coupled device (CCD) detector and includes 12 fiber-optic probes with a novel dual-path design. UV light was produced by a small arc deuterium lamp illuminating an optical fiber bundle. Twelve fiber-optic dipping probes were constructed with a reflection geometry. A 5 mm diameter lens was used to achieve a parallel light beam. The light passed back and forth through the flow-through cuvette defined by a sapphire window and a coated aluminium mirror. The mirror was cut in half and each segment was tilted and set at different distances from the window to obtain two separate paths with different lengths. Two receiver fibers were used for each probe to collect the transmitted light. The 24 receiver fibers from the 12 probes were bunched to a linear bundle and fed to an imaging spectrometer and the corresponding spectra were detected with a 512 x 512 pixel cooled CCD detector. The sampling interval was typically a few seconds for all probes. A software package was developed for data recording and on-line analysis. The program includes tools for multi-component analysis. The system was tested for different tablet formulations. Prednisone 50 mg tablets, normally used for control tests of dissolution baths, were followed for 3 h. Secondly, an extended release low dosage tablet was followed for 7 h resulting in a linear dissolution profile. Finally, a combination tablet containing two active drugs was tested for 60 min profiles. In the latter case, separate dissolution curves for the two active components were obtained. Future work will mainly focus on further development of the multi-component capability of the system. PMID:12062647

Johansson, Jonas; Cauchi, Michael; Sundgren, Mats

2002-07-01

92

Biorelevant in vitro dissolution testing of products containing micronized or nanosized fenofibrate with a view to predicting plasma profiles.  

PubMed

The ability of in vitro biorelevant dissolution tests to predict the in vivo performance of nanosized fenofibrate (Lipidil 145 ONE®) and microsized fenofibrate (Lipidil - Ter®) was evaluated in this study. In vitro dissolution was carried out using USP apparatus 2 (paddle method) with updated biorelevant media to simulate the pre- and postprandial states. Membrane filters with different pore sizes were evaluated for their ability to hold back undissolved, nanosized drug particles. It was shown that filters with pore sizes of 0.1 ?m and 0.02 ?m were able to separate molecularly dissolved drug from colloidal and undissolved particles. In vitro results obtained with a suitable filter were used to generate simulated plasma profiles in combination with two different models using STELLA® software: (a) under the assumption of no permeability restrictions to absorption and (b) under the assumption of a permeability restriction. The simulated plasma profiles were compared to in vivo data for the nanosized and the microsized formulation in the fasted and fed states. The first model approach resulted in good correlation for the microsized fenofibrate formulation, but the plasma profile of the formulation containing nanosized fenofibrate was overpredicted in the fasted state. The second model successfully correlated with in vivo data for both formulations, regardless of prandial state. Comparison of simulations with the two models indicates that in the fasted state, absorption of fenofibrate from the nanosized formulation is at least partly permeability-limited, while for the microsized formulation the dissolution of fenofibrate appears to be rate-determining. PMID:21074611

Juenemann, Daniel; Jantratid, Ekarat; Wagner, Christian; Reppas, Christos; Vertzoni, Maria; Dressman, Jennifer B

2011-02-01

93

Simulating Tablet Dissolution in Complex Hydrodynamic Environment with Lattice-Boltzmann Method  

NASA Astrophysics Data System (ADS)

Using the Lattice-Boltzmann method, we developed a 3D mesoscopic model to study the drug-dissolution process in a complex hydrodynamic environment involving spatially varying velocity and shear forces. The results showed turbulent flow in region above tablet, which was also obtained by visualization experiments. The dissolution profiles obtained by incorporating detailed kinetics showed good agreement with case studies from literature. The influence of the paddle speed and the size of the system were studied, and a multicomponent approach was also incorporated. Our results show how that the hydrodynamic environment would affect the dissolution process by changing the local concentration of components near the tablet and by the particle erosion under high fluid velocity. The code was also successfully parallelized so that the simulation of comparatively large system is now possible.

Raksit, Arpon; Sun, Ning; Pozin, Vadim; Gersappe, Dilip

2012-02-01

94

principle method based dissolution minerals kinds food materials closed system microwave digestion method measurement sodium potassium calcium magnesium iron zinc phosphorus concentrations ICP-OS.  

EPA Pesticide Factsheets

Did you mean: principle method based dissolution minerals kinds food materials closed system microwave digestion method measurement sodium potassium calcium magnesium iron zinc phosphorus concentrations ICP-OS. ?

95

Method for dissolution and stabilization of silica-rich fibers  

DOEpatents

A method is described 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. 1 fig.

Jantzen, C.M.

1997-11-11

96

Method for dissolution and stabilization of silica-rich fibers  

SciTech Connect

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

97

Analysis of nifedipine absorption from soft gelatin capsules using PBPK modeling and biorelevant dissolution testing.  

PubMed

Delayed absorption of nifedipine when administered as a 20 mg immediate release soft gelatin capsule to fasted volunteers has been reported. Physiologically based pharmacokinetic (PBPK) modeling and in vitro dissolution data were used to explore our hypothesis that at high doses of nifedipine it precipitates in the stomach. Plasma concentration-time profiles following different doses of nifedipine were simulated using commercial PBPK software and compared to in vivo data. In vitro dissolution tests were performed with Adalat 10 mg capsules in different volumes of fasted state simulated gastric fluid (FaSSGF). The discrepancy in plasma concentration-time profiles between the different nifedipine doses could be well simulated, assuming protracted dissolution for the 20 mg dose. Nifedipine release from one Adalat 10 capsule in 250 or 500 mL FaSSGF was completed within 15 min whereas when release from two capsules, corresponding to 20 mg nifedipine, was studied in 250 mL FaSSGF, a maximum of about 75% drug dissolved was observed after 15 min followed by a decline in the % dissolved to a final value of approximately 40%. Based on the in silico and in vitro results it can be concluded that the observed prolongation in nifedipine absorption following the 20 mg dose was likely caused by nifedipine precipitation in human stomach. PMID:20014280

Thelen, Kirstin; Jantratid, Ekarat; Dressman, Jennifer B; Lippert, Jörg; Willmann, Stefan

2010-06-01

98

Results from Nevada Nuclear Waste Storage Investigations (NNWSI) Series 3 spent fuel dissolution tests  

SciTech Connect

The dissolution and radionuclide release behavior of spent fuel in groundwater is being studied by the Yucca Mountain Project (YMP), formerly the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. Specimens prepared from pressurized water reactor fuel rod segments were tested in sealed stainless steel vessels in Nevada Test Site J-13 well water at 85{degree}C and 25{degree}C. The test matrix included three specimens of bare-fuel particles plus cladding hulls, two fuel rod segments with artificially defected cladding and water-tight end fittings, and an undefected fuel rod section with watertight end fittings. Periodic solution samples were taken during test cycles with the sample volumes replenished with fresh J-13 water. Test cycles were periodically terminated and the specimens restarted in fresh J-13 water. The specimens were run for three cycles for a total test duration of 15 months. 22 refs., 32 figs., 26 tabs.

Wilson, C.N.

1990-06-01

99

CO2CRC's Otway Residual Saturation and Dissolution Test: Using Reactive Ester Tracers to Determine Residual CO2 Saturation  

NASA Astrophysics Data System (ADS)

Residual trapping, that is CO2 held in the rock pore space due to capillarity, is an important storage mechanism in geo-sequestration of over the short to medium term (up to 1000 years). As such residual CO2 saturation is a critical reservoir parameter for assessing the storage capacity and security of carbon capture and storage (CCS). As a component of the CO2CRC's Residual Gas Saturation and Dissolution Test at the CO2CRC Otway Project site in Victoria (Australia), we have recently tested a suite of reactive esters (triacetin, tripropionin and propylene glycol diacetate) in a single well chemical tracer test to determine residual CO2 saturation. The goal of this project was to assess and validate a suite of possible tests that could be implemented to determine residual CO2 saturation. For this test, the chemical tracers were injected with a saturated CO2/water mixture into the formation (that is already at residual CO2 saturation) where they were allowed to 'soak' for approximately 10 days allowing for the partial hydrolysis of the esters to their corresponding carboxylic acids and alcohols. Water containing the tracers was then produced from the well resulting in over 600 tracer samples over a period of 12 hours. A selection of these samples were analysed for tracer content and to establish tracer breakthrough curves. To understand the behaviour of these chemical tracers in the downhole environment containing residually trapped supercritical CO2 and formation water, it is necessary to determine the supercritical CO2/water partition coefficients. We have previously determined these in the laboratory (Myers et al., 2012) and they are used here to model the tracer behaviour and provide an estimate of the residual CO2 saturation. Two different computational simulators were used to analyse the tracer breakthrough profiles. The first is based on simple chromatographic retardation and has been used extensively in single well chemical tracer tests to determine residual oil saturation and the second is based on TOUGH2. The estimates of residual saturation given by these models were similar giving a very low residual CO2 saturation value. We suspect that this low value might be due to CO2 being inadvertently dissolved in the near wellbore region prior to this test. This possible dissolution of CO2 may be attributed to the complexity of the multi-test sequence (including other tracer tests prior to this particular test) used in the overall program at of the Residual Gas Saturation and Dissolution Test. References Myers, M., Stalker, L., Ross, A., Dyt, C., Ho, K.-B., 2012. Method for the determination of residual carbon dioxide saturation using reactive ester tracers. Applied Geochemistry 27, 2148-2156.

Myers, M.; Stalker, L.; LaForce, T.; Pejcic, B.; Dyt, C.; Ho, K.; Ennis-King, J.

2013-12-01

100

Asymmetric flow field-flow fractionation (AF4) for the quantification of nanoparticle release from tablets during dissolution testing.  

PubMed

Nanoparticles composed of poly(DL-lactide-co-glycolide) (PLGA) represent promising colloidal drug carriers for improved drug targeting. Although most research activities are focused on intravenous application of these carriers the peroral administration is described to improve bioavailability of poorly soluble drugs. Based on these insights the manuscript describes a model tablet formulation for PLGA-nanoparticles and especially its analytical characterisation with regard to a nanosized drug carrier. Besides physico-chemical tablet characterisation according to pharmacopoeias the main goal of the study was the development of a suitable analytical method for the quantification of nanoparticle release from tablets. An analytical flow field-flow fractionation (AF4) method was established and validated which enables determination of nanoparticle content in solid dosage forms as well as quantification of particle release during dissolution testing. For particle detection a multi-angle light scattering (MALS) detector was coupled to the AF4-system. After dissolution testing, the presence of unaltered PLGA-nanoparticles was successfully proved by dynamic light scattering and scanning electron microscopy. PMID:24296046

Engel, A; Plöger, M; Mulac, D; Langer, K

2014-01-30

101

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

102

Development and validation of dissolution test for lopinavir, a poorly water-soluble drug, in soft gel capsules, based on in vivo data.  

PubMed

The objective of the present study was to develop and validate a dissolution test for lopinavir soft gel capsules (Kaletra), using a simulated absorption profile based on in vivo data. Different conditions such as surfactant concentration, apparatus and rotation speed were evaluated. In vivo release profiles were obtained from the literature. The fraction (and percentage) of dose absorbed (FA) was calculated by using Wagner-Nelson method. The best in vitro dissolution profile was obtained using Apparatus 2 (paddle) at 25 rpm, 1000 ml of medium with 2.3% of sodium lauryl sulfate and pH 6.0. Under these conditions a level-A in vitro-in vivo correlation (IVIVC) was obtained (r = 0.997). The in vitro dissolution samples were analyzed using a HPLC method and the validation was performed according to USP protocol. The method showed accuracy, precision, linearity and specificity within the acceptable range. Both the HPLC method and the in vitro dissolution method were validated and could be used to evaluate the release profile of lopinavir soft gel capsules. PMID:18403160

Donato, Eliane Maria; Martins, Laura Alegria; Fröehlich, Pedro Eduardo; Bergold, Ana Maria

2008-07-15

103

K Basin Sludge Conditioning Testing Nitric Acid Dissolution Testing of K East Area Sludge Composite, Small- and Large-Scale Testing  

SciTech Connect

This report describes work performed by Pacific Northwest National Laboratory (PNNL) for Numatec Hanford Corporation (NHC) to support the development of the K Basin Sludge Treatment System. For this work, testing was performed to examine the dissolution behavior of a K East Basin floor and Weasel Pit sludge composite, referred to as K East area sludge composite, in nitric acid at the following concentrations: 2 M, 4 M, 6 M and 7.8 M. With the exception of one high solids loading test the nitric acid was added at 4X the stoichiometric requirement (assuming 100% of the sludge was uranium metal). The dissolution tests were conducted at boiling temperatures for 24 hours. Most of the tests were conducted with {approximately}2.5 g of sludge (dry basis). The high solids loading test was conducted with {approximately}7 g of sludge. A large-scale dissolution test was conducted with 26.5 g of sludge and 620 mL of 6 M nitric acid. The objectives of this test were to (1) generate a sufficient quantity of acid-insoluble residual solids for use in leaching studies, and (2) examine the dissolution behavior of the sludge composite at a larger scale.

Carlson, C.D.; Delegard, C.H.; Burgeson, I.E.; Schmidt, A.J.; Silvers, K.L.

1999-04-02

104

Investigation of Methods to Control Niobium Wall Dissolution in Internal Tin Tube Nb3Sn Superconductors  

NASA Astrophysics Data System (ADS)

Nb3Sn superconductors fabricated by the ITT (Internal Tin Tube) method are subject to niobium wall dissolution during reaction heat treatment thereby negatively impacting Jc. This can be controlled to some extent by reducing the initial Sn/Cu ratio in the filament core. However, this approach often results in insufficient tin for complete reaction of the filament. An aluminum barrier has been explored as a means to prevent niobium dissolution during multiple stage heat treatments. The barrier is impervious to tin diffusion at the lower homogenizing temperatures thus preserving the niobium wall, but dissolves at the higher reaction temperature thereby permitting A15 formation. Barrier performance, Nb3Sn microstructure, and composition are discussed and the superconducting properties are presented.

Renaud, C. V.; Nachtrab, W. T.; Wong, T.

2010-04-01

105

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

DOEpatents

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 such transfer significantly impairs dissolution efficiency. In accordance with the invention, an amount of the above-mentioned solvent is added to the feed fluid being introduced to the contact zone, the solvent being added in an amount sufficient to effect reduction or elimination of the above-mentioned transfer. Preferably, the solvent is added to the feed fluid in an amount saturating or supersaturating the feed fluid under the conditions prevailing in the contact zone.

Kanak, Brant E. (Knoxville, TN) [Knoxville, TN; Stephenson, Michael J. (Oak Ridge, TN) [Oak Ridge, TN

1981-01-01

106

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

DOEpatents

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 transfer significantly impairs dissolution efficiency. In accordance with the invention, an amount of the above-mentioned solvent is added to the feed fluid being introduced to the contact zone, the solvent being added in an amount sufficient to effect reduction or elimination of the above-mentioned transfer. Preferably, the solvent is added to the feed fluid in an amount saturating or supersaturating the feed fluid under the conditions prevailing in the contact zone.

Kanak, B.E.; Stephenson, M.J.

1980-01-11

107

In vitro release of ketoprofen suppositories using the USP basket and the flow-through cell dissolution methods.  

PubMed

In order to study the release characteristics of ketoprofen suppositories under the hydrodynamic environment generated by USP Apparatus 1 and 4, the dissolution profiles of the Mexican reference product (100 mg) were determined. Phosphate buffer pH 8 and 1% sodium lauryl sulfate (SLS) aqueous solutions were proved as dissolution mediums. Baskets were rotated at 100 rpm with USP Apparatus 1 and different flow rates from 16-32 mL/min with USP Apparatus 4 were used. Drug samples were taken and quantified during 60 min by UV analysis at 260 nm. Mean dissolution time (MDT) and dissolution efficiency (DE) were calculated by model-independent methods. Data were also fitted to several kinetic models. Poor dissolution was found in both dissolution mediums when USP basket method was used (< 10% dissolved) while better results were obtained with USP Apparatus 4 when 1% SLS at 24 mL/min was used (43.6% dissolved, MDT of 25.5 min and DE of 25.0%). Kinetics showed a great variability when the USP Apparatus 1 was used, and Gompertz fitted well for data of 1% SLS at 24 mL/min (R(2)(adjusted) > 0.99). The results suggest the need to establish an adequate dissolution method to evaluate the release kinetics of ketoprofen from suppositories. PMID:24811800

Medina, José Raúl; Padilla, Adrián Roberto; Hurtado, Marcela; Cortés, Alma Rosa; Domínguez-Ramírez, Adriana Miriam

2014-05-01

108

K Basin Sludge Conditioning Testing Nitric Acid Dissolution Testing of K East Area Sludge Composite, Small and Large-Scale Testing  

Microsoft Academic Search

This report describes work performed by Pacific Northwest National Laboratory (PNNL) for Numatec Hanford Corporation (NHC) to support the development of the K Basin Sludge Treatment System. For this work, testing was performed to examine the dissolution behavior of a K East Basin floor and Weasel Pit sludge composite, referred to as K East area sludge composite, in nitric acid

C. D. Carlson; C. H. Delegard; I. E. Burgeson; A. J. Schmidt; K. L. Silvers

1999-01-01

109

Designing a dynamic dissolution method: a review of instrumental options and corresponding physiology of stomach and small intestine.  

PubMed

Development of new pharmaceutical compounds and dosage forms often requires in vitro dissolution testing with the closest similarity to the human gastrointestinal (GI) tract. To create such conditions, one needs a suitable dissolution apparatus and the appropriate data on the human GI physiology. This review discusses technological approaches applicable in biorelevant dissolutions as well as the physiology of stomach and small intestine in both fasted and fed state, that is, volumes of contents, transit times for water/food and various solid oral dosage forms, pH, osmolality, surface tension, buffer capacity, and concentrations of bile salts, phospholipids, enzymes, and Ca(2+) ions. The information is aimed to provide clear suggestions on how these conditions should be set in a dynamic biorelevant dissolution test. PMID:23494815

Culen, Martin; Rezacova, Anna; Jampilek, Josef; Dohnal, Jiri

2013-09-01

110

Development and validation of a dissolution test for a once-a-day combination tablet of immediate-release cetirizine dihydrochloride and extended-release pseudoephedrine hydrochloride.  

PubMed

A dissolution test for a once daily combination tablet containing 10 mg of cetirizine dihydrochloride (cetirizine HCl) for immediate release and 240 mg of pseudoephedrine hydrochloride (pseudoephedrine HCl) for extended release was developed and validated according to current ICH and FDA guidelines. The cetirizine HCl is contained within an outer layer of the tablet while a semipermeable membrane of cellulose acetate and polyethylene glycol controls the rate at which pseudoephedrine HCl is released from the tablet core. The dissolution method, which uses USP apparatus 2 with paddles rotating at 50 rpm, 1000 ml of deaerated water as the dissolution medium, and reversed-phased HPLC for quantitation, was demonstrated to be robust, discriminating, and transferable. These test conditions were selected after it was demonstrated that the cetirizine HCl portion of the tablet rapidly dissolved in aqueous media over the physiologically relevant pH range of 1.1-7.5, and that the extended-release profile of pseudoephedrine HCl was independent of dissolution conditions (i.e., apparatus, pH, and agitation). PMID:15975755

Likar, Michael D; Mansour, Hany L; Harwood, Jeffrey W

2005-09-15

111

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

PubMed

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 physiologically based pharmacokinetic (PBPK) modeling was applied to the prediction of food effects on the absorption of a poorly soluble drug, celecoxib, from 200mg capsules. A PBPK model was developed based on STELLA software using dissolution kinetics, solubility, standard GI parameters and post-absorptive disposition parameters. Solubility, dissolution profiles and initial dissolution rate from celecoxib 200mg capsules were measured in biorelevant and compendial media. Standard GI parameters (gastric emptying rate and fluid volume) were varied according to the dosing conditions. Disposition parameters were estimated by fitting compartmental models to the oral PK data, since intravenous data are not available for celecoxib. Predictions of food effects and average plasma profiles were evaluated using the AUC and C(max) and the difference factor (f(1)). An approximately 7-fold difference in the maximum percentage dissolved was observed in in vitro dissolution tests designed to represent the fed and fasted states. By contrast, the food effect estimated by simulating the plasma profiles with the PBPK model predicted only a slight delay in the peak plasma level ( approximately 1h), and modest increases in the C(max) and AUC of approximately 1.9-fold and 1.3-fold in the fed state, respectively. The PBPK approach, combining in silico simulation coupled with biorelevant dissolution test results, thus corresponds much better to the food effect observed for celecoxib in vivo. Additionally, point estimates of AUC and C(max) as well as f(1) calculations demonstrated clear advantages of using results in biorelevant rather than compendial media in the PBPK model. PMID:19465123

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

2009-09-01

112

Fluid dynamics test method  

NASA Technical Reports Server (NTRS)

Test method and apparatus determine fluid effective mass and damping in frequency range where effective mass may be considered as total mass less sum of slosh masses. Apparatus is designed so test tank and its mounting yoke are supported from structural test wall by series of flexures.

Gayman, W. H.

1974-01-01

113

Dissolution and particle size characterization of radioactive contaminants in Hanford facilities: Criteria for methods of measurement  

SciTech Connect

The purpose of this document is to discuss experimental methods that can be applied to evaluate the rate at which an actinide material is likely to dissolve in biological fluids. Criteria are recommended for the design and conduct of meaningful experimental procedures to sample a representative size fraction of the source material, to measure the rate of radionuclide dissolution, and to apply the results to assign the material to an appropriate ICRP Publication-30 lung retention class (or mixture of classes). 26 refs., 3 figs., 3 tabs.

Briant, J.K.; James, A.C.

1990-08-01

114

Test Plan for Series 3 NNWSI Spent Fuel Leaching/Dissolution Tests.  

National Technical Information Service (NTIS)

The Series 3 tests will differ from the Series 2 tests in that the Series 3 tests will be run at 85 sup 0 C (J-13 water) in sealed 304 stainless steel (SS) test vessels. The current NNWSI reference spent fuel container material is 304L SS. The candidate N...

C. N. Wilson

1986-01-01

115

TRANSPORT OF REACTING SOLUTES SUBJECT TO A MOVING DISSOLUTION BOUNDARY: NUMERICAL METHODS AND SOLUTIONS.  

USGS Publications Warehouse

In this paper we consider examples of chemistry-affected transport processes in porous media. A moving boundary problem which arises during transport with precipitation-dissolution reactions is solved by three different numerical methods. Two of these methods (one explicit and one implicit) are based on an integral formulation of mass balance and lead to an approximation of a weak solution. These methods are compared to a front-tracking scheme. Although the two approaches are conceptually different, the numerical solutions showed good agreement. As the ratio of dispersion to convection decreases, the methods based on the integral formulation become computationally more efficient. Specific reactions were modeled to examine the dependence of the system on the physical and chemical parameters.

Willis, Catherine; Rubin, Jacob

1987-01-01

116

The influence of amorphization methods on the apparent solubility and dissolution rate of tadalafil.  

PubMed

This study for the first time investigates the solubility and dissolution rate of amorphous tadalafil (Td) - a poorly water soluble chemical compound which is commonly used for treating the erectile dysfunction. To convert the crystalline form of Td drug to its amorphous counterpart we have employed most of the commercially available amorphization techniques i.e. vitrification, cryogenic grinding, ball milling, spray drying, freeze drying and antisolvent precipitation. Among the mentioned methods only quenched cooling of the molten sample was found to be an inappropriate method of Td amorphization. This is due to the thermal decomposition of Td above 200°C, as proved by the thermogravimetric analysis (TGA). Disordered character of all examined samples was confirmed using differential scanning calorimetry (DSC) and X-ray powder diffraction (PXRD). In the case of most amorphous powders, the largest 3-fold increase of apparent solubility was observed after 5min, indicating their fast recrystallization in water. On the other hand, the partially amorphous precipitate of Td and hypromellose enhanced the solubility of Td approximately 14 times, as compared with a crystalline substance, which remained constant for half an hour. Finally, disk intrinsic dissolution rate (DIDR) of amorphous forms of Td was also examined. PMID:24907679

Wlodarski, K; Sawicki, W; Paluch, K J; Tajber, L; Grembecka, M; Hawelek, L; Wojnarowska, Z; Grzybowska, K; Talik, E; Paluch, M

2014-10-01

117

Calorimetric determination of dissolution enthalpy with a novel flow-through method.  

PubMed

A new calorimetric flow-through system for determining the enthalpies of dissolution with small amount of solids (<1mg) was developed. The system was designed to be used as an add-on cell with a 4 ml twin heat conduction calorimeter 2277 TAM but the principle is adoptable also for other heat conduction calorimeters. The system was tested with two salts (NaCl, KCl), sucrose and different polymorphic forms of theophylline at 25 degrees C and 40 degrees C by using water as the solvent. The system gave more accurate and precise results at 25 degrees C. The precision was not affected by the extent of the dissolution enthalpy. The accuracy was dependent on the calibration utilized but even the normal electrical calibration gave acceptable values. The results obtained at 40 degrees C were also acceptable but not as good as at 25 degrees C due to heat leaks. The effect of heat leaks can be minimized by heating the inflowing solvent outside the calorimeter prior to entering the flow-through cell. PMID:20674217

Lehto, Vesa-Pekka; Tenho, Mikko; Hämäläinen, Olli-Pekka; Salonen, Jarno

2010-12-01

118

Development of a bio-relevant dissolution test device simulating mechanical aspects present in the fed stomach.  

PubMed

A novel bio-relevant in vitro dissolution device was designed to mimic intragastric conditions after food intake paying particular consideration to mechanical aspects: the Fed Stomach Model (FSM). The FSM represents a fully computer-controlled dynamic flow-through system, in which dosage forms are hosted in so-called gastric vessels. Dosage form movement profiles as well as pressures can be simulated in a physiologically relevant manner. This proof-of-concept study aimed at the investigation of the effects of individual parameters and complex test programs on the drug delivery behavior of diclofenac sodium bilayer extended release tablets. Magnetic marker monitoring experiments demonstrated the applicability of the FSM to simulate intragastric movement velocities of solid oral dosage forms equivalent to in vivo data. Dissolution experiments revealed the relevance of all simulated parameters (i.e. pressure, dosage form movement and pump rate). Moreover, three different test scenarios with test programs specific for fundus, antrum and gastric emptying considered the variability of intragastric transit of solid oral dosage forms after food intake and were confirmed to be reasonable. Dissolution rates were low under conditions specific for fundus owing to low shear stresses. In contrast, higher amounts of the drug were released under high stress conditions simulating antral transit and gastric emptying. Concluding, the FSM can be a valuable tool for bio-relevant dissolution testing due to its potential of precise and reproducible simulation of mechanical parameters characteristic for the fed stomach. PMID:24051217

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

2014-06-16

119

Ignitability test method. II  

NASA Technical Reports Server (NTRS)

To determine functional performance of initiating devices, the NASA's Langley Research Center's novel ignitability research on percussion primers has been expanded in 1989 to include measurements of function time, the evaluation of six primer lots (five types), and the determination of the effects of the military cold-temperature requirement of -65 F and primer output closure disks. This test method, a major improvement over the prior primer output test methods, fully met all objectives, while showing a significant amount of ignition variability.

Bement, Laurence J.; Schimmel, Morry L.

1990-01-01

120

Ignitability test method  

NASA Technical Reports Server (NTRS)

To overcome serious weaknesses in determining the performance of initiating devices, a novel 'ignitability test method', representing actual design interfaces and ignition materials, has been developed. Ignition device output consists of heat, light, gas an burning particles. Past research methods have evaluated these parameters individually. This paper describes the development and demonstration of an ignitability test method combining all these parameters, and the quantitative assessment of the ignition performance of two widely used percussion primers, the M42C1-PA101 and the M42C2-793. The ignition materials used for this evaluation were several powder, granule and pellet sizes of black powder and boron-potassium nitrate. This test method should be useful for performance evaluation of all initiator types, quality assurance, evaluation of ignition interfaces, and service life studies of initiators and ignition materials.

Bement, Laurence J.; Schimmel, Morry L.

1989-01-01

121

Size distributions of micro-bubbles generated by a pressurized dissolution method  

NASA Astrophysics Data System (ADS)

Size of micro-bubbles is widely distributed in the range of one to several hundreds micrometers and depends on generation methods, flow conditions and elapsed times after the bubble generation. Although a size distribution of micro-bubbles should be taken into account to improve accuracy in numerical simulations of flows with micro-bubbles, a variety of the size distribution makes it difficult to introduce the size distribution in the simulations. On the other hand, several models such as the Rosin-Rammler equation and the Nukiyama-Tanazawa equation have been proposed to represent the size distribution of particles or droplets. Applicability of these models to the size distribution of micro-bubbles has not been examined yet. In this study, we therefore measure size distribution of micro-bubbles generated by a pressurized dissolution method by using a phase Doppler anemometry (PDA), and investigate the applicability of the available models to the size distributions of micro-bubbles. Experimental apparatus consists of a pressurized tank in which air is dissolved in liquid under high pressure condition, a decompression nozzle in which micro-bubbles are generated due to pressure reduction, a rectangular duct and an upper tank. Experiments are conducted for several liquid volumetric fluxes in the decompression nozzle. Measurements are carried out at the downstream region of the decompression nozzle and in the upper tank. The experimental results indicate that (1) the Nukiyama-Tanasawa equation well represents the size distribution of micro-bubbles generated by the pressurized dissolution method, whereas the Rosin-Rammler equation fails in the representation, (2) the bubble size distribution of micro-bubbles can be evaluated by using the Nukiyama-Tanasawa equation without individual bubble diameters, when mean bubble diameter and skewness of the bubble distribution are given, and (3) an evaluation method of visibility based on the bubble size distribution and bubble number density is proposed, and the evaluated visibility agrees well with the visibility measured in the upper tank.

Taya, C.; Maeda, Y.; Hosokawa, S.; Tomiyama, A.; Ito, Y.

2012-03-01

122

Rail shear test method  

NASA Technical Reports Server (NTRS)

The results of both an experimental test program and a finite element analysis of selected graphite/polyimide rail shear test specimens are discussed. The two dimensional finite element analysis includes both mechanical and thermal loading (differential expansion) of the specimens and their elastic rails. Parameters in this analysis of unidirectional and symmetric, balanced angle-ply laminates include ply layup angles, the effect of flexible rails, the method of load introduction to the specimen and the effect of uniform heating of the specimen and rails. Two types of tensile rail shear fixtures were investigated experimentally: a uniform thickness, bolted-rail shear fixture loaded diagonally across the specimen test section; and a tapered thickness, bonded-rail shear fixture loaded axially along the center-line of the specimen test section. Test results include room-temperature and 589K strain data taken from the center of the specimen test section during loading.

Garcia, R.; Mcwithey, R. R.

1979-01-01

123

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

124

In Vitro Dissolution Tests of Plutonium and Americium Containing Contamination Originating From ZPPR Fuel Plates  

SciTech Connect

Assessing the extent of internal dose is of concern whenever workers are exposed to airborne radionuclides or other contaminants. Internal dose determinations depend upon a reasonable estimate of the expected biological half-life of the contaminants in the respiratory tract. One issue with refractory elements is determining the dissolution rate of the element. Actinides such as plutonium (Pu) and Americium (Am) tend to be very refractory and can have biological half-lives of tens of years. In the event of an exposure, the dissolution rates of the radionuclides of interest needs to be assessed in order to assign the proper internal dose estimates. During the November 2011 incident at the Idaho National Laboratory (INL) involving a ZPPR fuel plate, air filters in a constant air monitor (CAM) and a giraffe filter apparatus captured airborne particulate matter. These filters were used in dissolution rate experiments to determine the apparent dissolution half-life of Pu and Am in simulated biological fluids. This report describes these experiments and the results. The dissolution rates were found to follow a three term exponential decay equation. Differences were noted depending upon the nature of the biological fluid simulant. Overall, greater than 95% of the Pu and 93% of the Am were in a very slow dissolving component with dissolution half-lives of over 10 years.

William F. Bauer; Brian K. Schuetz; Gary M. Huestis; Thomas B. Lints; Brian K. Harris; R. Duane Ball; Gracy Elias

2012-09-01

125

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

126

Dissolution testing and potentiometric determination of famciclovir in pure, dosage forms and biological fluids.  

PubMed

The performance characteristics of two new plastic membrane ion selective electrodes (ISEs) used for the determination of famciclovir (Fcv) based on the ion associate of Fcv with phosphotungstic acid (PTA) or phosphomolybdic acid (PMA) are described. Different experimental conditions as type of plasticizer to be incorporated in the membrane, life span, effect of soaking, pH, temperature, and interferences were studied. Both electrodes showed similar performance under these conditions, exhibiting Nernstian slopes of S (Fcv-PTA)=58.60±0.84 mV/decade and S (Fcv-PMA)=58.77±0.68 mV/decade within a usable concentration range of 10??-10?² [Fcv/M] at 298/K. Famciclovir was assayed potentiometrically in its pure solution, pharmaceutical preparations and biological fluids (urine and plasma) using proposed electrodes under batch and flow injection analysis (FIA) conditions with a recovery % ranging between 96.76% and 102.83% having RSD of 0.66%-1.81%. The electrodes were also successfully applied in the determination of the dissolution profile of Fcv tablets and the results came in agreement with the validated results of the HPLC method obtained from the quality control unit of the company producing the tablets. PMID:23017353

Rezk, Mohamed S; El Nashar, Rasha M

2013-02-01

127

The Use of Experimental Design Principles in Dissolution Method Development: Development of a Discriminating Dissolution Method for Sprycel Film-Coated Tablets  

Microsoft Academic Search

Sprycel® (dasatinib) film-coated tablet is a new medicinal product that was recently launched for the treatment of chronic\\u000a myelogenous leukemia. Due to the early success of dasatinib in phase I clinical trials, development activities were accelerated\\u000a significantly to enable wide distribution of this drug to patients. As a BCS class II compound, dissolution was considered\\u000a a critical quality attribute of

William P. Fish; Joel Young; Pankaj Shah; Zhihui Gao

2009-01-01

128

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

129

Solvent-based dissolution method to sample gas-phase volatile organic compounds for compound-specific isotope analysis.  

PubMed

An investigation was carried out to develop a simple and efficient method to collect vapour samples for compound specific isotope analysis (CSIA) by bubbling vapours through an organic solvent (methanol or ethanol). The compounds tested were benzene and trichloroethylene (TCE). The dissolution efficiency was tested for different air volume injections, using flow rates ranging from 25ml/min to 150ml/min and injection periods varying between 10 and 40min. Based on the results, complete mass recovery for benzene and TCE in both solvents was observed for the flow rates of 25 and 50ml/min. However, small mass loss was observed at increased flow rate. At 150ml/min, recovery was on average 80±17% for benzene and 84±10% for TCE, respectively in methanol and ethanol. The ?(13)C data measured for benzene and TCE dissolved in both solvents were reproducible and were stable independently of the volume of air injected (up to 6L) or the flow rate used. The stability of ?(13)C values hence underlines no isotopic fractionation due to compound-solvent interaction or mass loss. The development of a novel and simple field sampling technique undertaken in this study will facilitate the application of CSIA to diverse gas-phase volatile organic compound studies, such as atmospheric emissions, soil gas or vapour intrusion. PMID:24360256

Bouchard, Daniel; Hunkeler, Daniel

2014-01-17

130

FIELD TESTING OF ROCK HARDNESS AND ITS RELATIONSHIP TO LIMESTONE DISSOLUTION IN GUILIN, SOUTHERN CHINA  

Microsoft Academic Search

This research investigates the relationship between rock hardness and limestone dissolution. Bedrocks at Guilin in subtropical southern China are mainlY Devonian and Carboniferous limestone and dolostone. The overburden Triassic and Cretaceous mudstones and sandstones occur sporadically as a result of extensive weathering and dissection. Major surface landforms in Guilin are steep-sided karst towers. A type N Schmidt Hammer I·vas used

Tao Tang

131

Bio-relevant dissolution testing of hard capsules prepared from different shell materials using the dynamic open flow through test apparatus.  

PubMed

Current compendial dissolution and disintegrating testing is unable to mimic physiological conditions affecting gastric drug release from immediate release dosage forms. In order to obtain more realistic data, a novel test setup was developed that we term a 'dynamic open flow through test apparatus'. It is based on the previously described dissolution stress test device and attempts to simulate the intra-gastric dissolution conditions pertinent to immediate release dosage forms administered under fasting conditions with respect to flow rates, intra-gastric temperature profiles and gastric motility. The concept of the dynamic open flow through test apparatus has been tested using five different types of hard capsules: conventional hard gelatin capsules (HGC), three hypromellose based capsules (Vcaps, Vcaps Plus and DRcaps) and pullulan based capsules (Plantcaps). These were of different sizes but all contained 100mg caffeine in each formulation, adjusted to avoid buoyancy by addition of excipient. When the capsules were stressed in the apparatus under the dynamic flow conditions applying mild pressure simulating gastric motility, release from release from Vcaps Plus, Vcaps and Plantcaps capsules was very well comparable to HGC. Capsules are usually swallowed with cold water and the temperature dependency of release from gelatin was noted as a significant factor, since heat exchange in the stomach is slow. PMID:24021609

Garbacz, Grzegorz; Cadé, Dominique; Benameur, Hassan; Weitschies, Werner

2014-06-16

132

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

2013-05-01

133

Sound method of testing  

SciTech Connect

Acoustic emission devices, which have been available for more than 20 years, have become widely used and applied only during the last 5 years because of system refinements. Acoustic emission (AE) systems can now locate cracks and fractures as small as one-thousandth of a millimeter in pressurized vessels and steam valves, or any plastic or metal material that is subject to stress or pressure. The same systems can also hear fracture emissions from geologic masses. Because AE systems are relatively inexpensive and provide information quickly, they often appear in conjunction with other nondestructive testing methods such as radiography, ultrasonics, thermography, optical holography, eddy curent, and computer tomography. The future points to AE devices that may detect structural defects on offshore oil rigs, and in oil and gas pipelines. (SC)

Not Available

1983-09-01

134

Time evolution of diameter of micro-bubbles generated by a pressurized dissolution method  

NASA Astrophysics Data System (ADS)

Size distributions of micro-bubbles and concentrations of dissolved oxygen in water in a square duct downstream of the decompression nozzle were measured to investigate the time evolution of bubble diameter and the mass transfer of dissolved gas between bubbles and water after bubble generation in a pressurized dissolution method. A numerical simulation based on the Rayleigh-Plesset equation was also carried out to predict time evolutions of bubble diameter and concentration of dissolves gas. The validity of the prediction was discussed through the comparison between the predictions and the experiments. As a result, the following conclusions were obtained: (1) When cavitation does not occur in the decompression nozzle, few micro-bubbles are generated at the nozzle and the mass transfer rate between bubbles and water in the downstream region of the nozzle is low due to a low interface area concentration. The mass transfer due to bubble nucleation is negligibly small in the downstream region of the decompression nozzle in spite of the supersaturated concentration of the dissolved gas. (2) When cavitation occurs in the nozzle, a lot of micro-bubbles are generated at the nozzle and therefore, the mass transfer rate between the phases becomes high. Hence, the bubble diameter and the void fraction increase and the concentration of dissolved gas in water decreases with the time elapsed after the bubble generation. (3) The proposed numerical method can reasonably predict time evolution of bubble size distributions, void fractions and concentrations of dissolved gas, provided that a reliable initial condition is available. Since the numerical simulation assumes that no bubble nucleation occurs in the downstream region of the nozzle, the agreement between the prediction and the experiments proves low influence of the bubble nucleation on the mass transfer between the phases.

Ishii, Kazuya; Fujimoto, Shudai; Hosokawa, Shigeo; Tomiyama, Akio; Ito, Yoshihiro; Maeda, Yasunari

2014-04-01

135

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

2011-02-20

136

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

2013-01-01

137

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

138

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

PubMed

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 forces generated during propagation, and loss of water contact when the dosage form is located in an intestinal air pocket. The new apparatus was evaluated using a diclofenac extended release (ER) tablet. The in vitro dissolution profiles were compared between the novel test apparatus and a conventional dissolution apparatus (USP II). These data were compared with the profiles of plasma concentration versus time that were obtained after the administration of an ER tablet to 24 healthy volunteers under fasting conditions. Multiple peaks were observed in individual plasma concentration-time profiles after the intake of the reference ER tablet. Standard dissolution testing showed typical characteristics of an almost continuous release for this formulation; however, dissolution testing with the novel apparatus suggested that the diclofenac release from the ER tablets would be extremely variable and dependent on the applied stress. The data suggest that the observed multiple peaks of plasma concentration after dosing of the ER diclofenac tablets are most probably caused by sensitivity to physical stress events during gastrointestinal transit. PMID:18582568

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

2008-10-01

139

PILOT SCALE STUDIES ON DISSOLUTION PROCESSES FOR NUCLEAR FUELS. II. ALUMINUM, MAGNESIUM, STAINLESS STEEL DECANNING, AND NON-IRRADIATED URANIUM METAL DISSOLUTION TESTS IN A PILOT RECIRCULATION DISSOLVER  

Microsoft Academic Search

A detailed description of a half scale pilot dissolver is given. The results of four series of runs including aluminium, magnesium and stainless steel decladding and dissolution of non-irradiated uranium metal are summarized and discussed. The reaction rates measured in the pilot dissolver and those obtained in laboratory equipment were in agreement. Means for instantaneous measurement of the reaction rate

A. Hasler; J. Centeno; Y. Marchant; R. Van Eylen

1967-01-01

140

Novel Application of MRI Technique Combined with Flow-Through Cell Dissolution Apparatus as Supportive Discriminatory Test for Evaluation of Controlled Release Formulations  

PubMed Central

Dissolution studies cannot distinguish phenomena occurring inside the dosage forms when studying formulation with similar dissolution profiles—such formulations can behave differently when considering their physical changes. The application of flow-through dissolution apparatus integrated with magnetic resonance imaging (MRI) system for discriminative evaluation of controlled release dosage forms with similar dissolution profiles was presented. Hydrodynamically balanced systems (HBS) containing l-dopa and various grades hydroxypropyl methylcelluloses were prepared. The dissolution studies of l-dopa were performed at high field (4.7 T) MR system with MR-compatible flow-through cell. MRI was done with 0.14?×?0.14?×?1-mm spatial resolution and temporal resolution of 10 min to record changes of HBS parameters during dissolution in 0.1 M HCl. Structural and geometrical changes were evaluated using the following parameters: total area of HBS cross-section, its Feret’s diameter, perimeter and circularity, area of hydrogel layer, and “dry core” area. While the dissolution profiles of l-dopa were similar, the image analysis revealed differences in the structural and geometrical changes of the HBS. The mechanism of drug release from polymeric matrices is a result of synergy of several different phenomena occurring during dissolution and may differ between formulations, yet giving similar dissolution profiles. A multivariate analysis was performed to create a model taking into account dissolution data, data from MRI, information about chemical structure, and polymer viscosity. It provided a single model for all the formulations which was confirmed to be competent. The presented method has merit as a potential Process Analytical Technology tool.

Kulinowski, Piotr; Mendyk, Aleksander; Mlynarczyk, Anna; Jachowicz, Renata

2010-01-01

141

A liquid chromatography method for quantifying caffeine dissolution from pharmaceutical formulations into colloidal, fat-rich media  

Microsoft Academic Search

A simple and rapid high-performance liquid-chromatography method is presented that permits quantification of caffeine in colloidal fat emulsions proposed as new ‘biorelevant’ dissolution media (Intralipid™ and various milks). Using a mobile phase of 0.1M sodium acetate (pH 4.0) and acetonitrile (89.5:10.5, v\\/v) at 1mlmin?1, the drug and internal standard (7-?-hydroxyethyltheophylline) were eluted within 8min. Caffeine extraction was undertaken by protein

Hywel D. Williams; David A. Barrett; Robert Ward; Ian J. Hardy; Colin D. Melia

2010-01-01

142

Re-Examining the Dissolution of Spent Fuel: A Comparison of Different Methods for Calculating Rates.  

National Technical Information Service (NTIS)

Dissolution rates for spent fuel have typically been reported in terms of a rate normalized to the surface area of the specimen. Recent evidence has shown that neither the geometric surface area nor that measured with BET accurately predicts the effective...

B. D. Hanson R. B. Stout

2004-01-01

143

Application of biorelevant dissolution tests to the prediction of in vivo performance of diclofenac sodium from an oral modified-release pellet dosage form  

Microsoft Academic Search

In vitro biorelevant dissolution tests enabling the prediction of in vivo performance of an oral modified-release (MR) dosage form were developed in this study. In vitro dissolution of MR diclofenac sodium pellets containing 100mg active ingredient was evaluated under simulated pre- and postprandial conditions using USP Apparatus 3 (reciprocating cylinder, Bio-Dis) and 4 (flow-through cell) and results compared with compendial

Ekarat Jantratid; Vincenzo De Maio; Emanuela Ronda; Valentina Mattavelli; Maria Vertzoni; Jennifer B. Dressman

2009-01-01

144

In Vitro Aqueous Fluid-Capacity-Limited Dissolution Testing of Respirable Aerosol Drug Particles Generated from Inhaler Products  

Microsoft Academic Search

Purpose  To develop a unique in vitro aqueous fluid-capacity-limited dissolution system for the kinetic assessment of respirable aerosol drug particles from inhaler\\u000a products.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Aerosol particles of 5 inhaled corticosteroids (ICSs) from 7 inhaler products were collected in the aerodynamic 2.1–3.3 or\\u000a 4.7–5.8 ?m on the filter membranes using the Andersen cascade impactor. Each filter membrane was then placed onto the donor\\u000a compartment

Deepika Arora; Kumar A. Shah; Matthew S. Halquist; Masahiro Sakagami

2010-01-01

145

Effects of seafloor and laboratory dissolution on the Mg/Ca composition of Globigerinoides sacculifer and Orbulina universa tests — A laser ablation ICPMS microanalysis perspective  

NASA Astrophysics Data System (ADS)

Partial or selective dissolution of planktonic foraminiferal tests on the seafloor has been shown to alter original test Mg/Ca compositions and thus may limit the accuracy of Mg/Ca-based thermometry for reconstructions of past sea surface temperatures. We have employed laser ablation ICPMS to determine the extent of dissolution-caused changes in Mg/Ca distribution across individual chamber walls of the planktonic foraminifera Globigerinoides sacculifer and Orbulina universa. G. sacculifer samples collected from a core-top depth transect in the NE Indian Ocean and laboratory dissolution experiments show little if any evidence of preferential removal of Mg-rich calcite layers by progressive dissolution of the tests. We attribute the absence of selective dissolution to the banded distribution of Mg across the chamber walls of these foraminiferal species and to the minimal presence of calcite crusts with relatively low-Mg composition on the outer surfaces of tests. Mg/Ca microanalyses of G. sacculifer from core-top samples further indicate that for samples collected above the calcite lysocline the effect of postdepositional dissolution on Mg/Ca sample mean values is minimal and within the uncertainty of Mg/Ca thermometry (i.e. ± 0.4 mmol/mol; ± 0.8 °C at ˜ 28 °C). Comparison with previously published results for G. sacculifer supports these observations. Simple modelling of G. sacculifer test dissolution indicates that selective removal of calcite with high-Mg/Ca values from within the final chamber of G. sacculifer test appears insufficient to cause the ˜ 10% decrease in Mg/Ca values observed above calcite lysocline. These changes in test composition might be related to development/removal as a function of ?[CO 32-] of a thin diagenetic surface coating which has a relatively high-Mg/Ca composition (i.e. 20-25 mmol/mol).

Sadekov, Aleksey Yu.; Eggins, Stephen M.; Klinkhammer, Gary P.; Rosenthal, Yair

2010-04-01

146

Comparative dissolution studies of rectal formulations using the Basket, the Paddle and the Flow-Through methods. I. Paracetamol in suppositories and soft gelatin capsules of both hydrophilic and lipophilic types.  

PubMed

The applicabilities of the Paddle, the Basket and the Flow-Through methods have been investigated for seven different rectal compositions of hydrophilic and lipophilic type. The formulations were studied with respect to in vitro dissolution rate and behaviour in the different techniques. It was found that the composition has a considerable influence on the behaviour of the dosage form and this must be taken into account when judging the applicabilities of the three dissolution tests. The Paddle, the Basket and the Flow-Through methods are considered to be equivalent methods for the dissolving suppositories tested. The Flow-Through method is applicable for all the seven compositions tested; however, a low flow rate (8 ml/min) is necessary to use for soft gelatin capsules when both the coefficient of variation and the behaviour of the dosages within the techniques is taken into consideration. PMID:2624705

Gjellan, K; Graffner, C

1989-01-01

147

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

148

Simultaneous UV imaging and raman spectroscopy for the measurement of solvent-mediated phase transformations during dissolution testing.  

PubMed

The current work reports the simultaneous use of UV imaging and Raman spectroscopy for detailed characterization of drug dissolution behavior including solid-state phase transformations during dissolution. The dissolution of drug substances from compacts of sodium naproxen in 0.1 HCl as well as theophylline anhydrate and monohydrate in water was studied utilizing a flow-through setup. The decreases in dissolution rates with time observed by UV imaging were associated with concomitant solid form changes detected by Raman spectroscopy. Sodium naproxen and theophylline anhydrate were observed to convert to the more stable forms (naproxen, and theophylline monohydrate) within approximately 5 min. Interestingly, the new approach revealed that three intermediate forms are involved in the dissolution process prior to the appearance of the neutral naproxen during dissolution in an acidic medium. The combination of UV imaging and Raman spectroscopy offers a detailed characterization of drug dissolution behavior in a time-effective and sample-sparing manner. PMID:24496995

Østergaard, Jesper; Wu, Jian X; Naelapää, Kaisa; Boetker, Johan P; Jensen, Henrik; Rantanen, Jukka

2014-04-01

149

Summary of results from the Series 2 and Series 3 NNWSI [Nevada Nuclear Waste Storage Investigations] bare fuel dissolution tests  

SciTech Connect

The Nevada Nuclear Waste Storage Investigations (NNWSI) Project is studying dissolution and radionuclide release behavior of spent nuclear fuel in Nevada Test Site groundwater. Specimens were tested for multiple cycles in J-13 well water. The Series 2 tests were run in unsealed silica vessels under ambient hot cell air (25{sup 0}C) for five cycles for a total of 34 months. The Series 3 tests were run in sealed stainless steel vessels at 25{sup 0}C and 85{sup 0}C for three cycles for a total of 15 months. Selected summary results from Series 2 and Series 3 tests with bare fuel specimens are reported. Uranium concentrations in later test cycles ranged from 1 to 2 {mu}g/ml in the Series 2 Tests versus about 0.1 to 0.4 {mu}g/ml in Series 3 with the lowest concentrations occurring in the 85{sup 0}C tests. Preferential release of fission products Cs, I, Sr and Tc, and activation product C-14, was indicated relative to the actinides. Tc-99 and Cs-137 activities measured in solution after Cycle 1 increased linearly with time, with the rate of increase greater at 85{sup 0}C than at 25{sup 0}C. 8 refs., 8 figs., 3 tabs.

Wilson, C.N.

1987-11-01

150

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

2013-08-01

151

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

152

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

2013-07-01

153

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

154

Index to EPA Test Methods.  

National Technical Information Service (NTIS)

To respond to frequent requests for agency test methods, Region 1 Library staff developed this methods index as a tool to help locate copies of them. Confirming that there was no one volume containing all agency methods and no comprehensive list of them, ...

P. Nelson

2003-01-01

155

Development and validation of a dissolution test for a once-a-day combination tablet of immediate-release cetirizine dihydrochloride and extended-release pseudoephedrine hydrochloride  

Microsoft Academic Search

A dissolution test for a once daily combination tablet containing 10mg of cetirizine dihydrochloride (cetirizine HCl) for immediate release and 240mg of pseudoephedrine hydrochloride (pseudoephedrine HCl) for extended release was developed and validated according to current ICH and FDA guidelines. The cetirizine HCl is contained within an outer layer of the tablet while a semipermeable membrane of cellulose acetate and

Michael D. Likar; Hany L. Mansour; Jeffrey W. Harwood

2005-01-01

156

Test methods for textile composites  

NASA Technical Reports Server (NTRS)

Various test methods commonly used for measuring properties of tape laminate composites were evaluated to determine their suitability for the testing of textile composites. Three different types of textile composites were utilized in this investigation: two-dimensional (2-D) triaxial braids, stitched uniweave fabric, and three-dimensional (3-D) interlock woven fabric. Four 2-D braid architectures, five stitched laminates, and six 3-D woven architectures were tested. All preforms used AS4 fibers and were resin-transfer-molded with Shell RSL-1895 epoxy resin. Ten categories of material properties were investigated: tension, open-hole tension, compression, open-hole compression, in-plane shear, filled-hole tension, bolt bearing, interlaminar tension, interlaminar shear, and interlaminar fracture toughness. Different test methods and specimen sizes were considered for each category of test. Strength and stiffness properties obtained with each of these methods are documented in this report for all the material systems mentioned above.

Minguet, Pierre J.; Fedro, Mark J.; Gunther, Christian K.

1994-01-01

157

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?  

Microsoft Academic Search

The carbon emissions trading market has created a need for standard methods for the determination of biogenic content (?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

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

2010-01-01

158

Predicting the oral pharmacokinetic profiles of multiple-unit (pellet) dosage forms using a modeling and simulation approach coupled with biorelevant dissolution testing: Case example diclofenac sodium.  

PubMed

The objective of this research was to characterize the dissolution profile of a poorly soluble drug, diclofenac, from a commercially available multiple-unit enteric coated dosage form, Diclo-Puren® capsules, and to develop a predictive model for its oral pharmacokinetic profile. The paddle method was used to obtain the dissolution profiles of this dosage form in biorelevant media, with the exposure to simulated gastric conditions being varied in order to simulate the gastric emptying behavior of pellets. A modified Noyes-Whitney theory was subsequently fitted to the dissolution data. A physiologically-based pharmacokinetic (PBPK) model for multiple-unit dosage forms was designed using STELLA® software and coupled with the biorelevant dissolution profiles in order to simulate the plasma concentration profiles of diclofenac from Diclo-Puren® capsule in both the fasted and fed state in humans. Gastric emptying kinetics relevant to multiple-units pellets were incorporated into the PBPK model by setting up a virtual patient population to account for physiological variations in emptying kinetics. Using in vitro biorelevant dissolution coupled with in silico PBPK modeling and simulation it was possible to predict the plasma profile of this multiple-unit formulation of diclofenac after oral administration in both the fasted and fed state. This approach might be useful to predict variability in the plasma profiles for other drugs housed in multiple-unit dosage forms. PMID:24462791

Kambayashi, Atsushi; Blume, Henning; Dressman, Jennifer B

2014-07-01

159

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

Microsoft Academic Search

SUMMARY 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

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

2001-01-01

160

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

Microsoft Academic Search

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

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

2001-01-01

161

HEPA filter dissolution process  

DOEpatents

A process is described 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. 4 figures.

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

1994-02-22

162

Special test methods for batteries  

NASA Technical Reports Server (NTRS)

Various methods are described for measuring heat generation in primary and secondary batteries as well as the specific heat of batteries and cell thermal conductance. Problems associated with determining heat generation in large batteries are examined. Special attention is given to monitoring temperature gradients in nickel cadmium cells, the use of auxiliary electrodes for conducting tests on battery charge control, evaluating the linear sweep of current from charge to discharge, and determining zero current voltage. The fast transient behavior of batteries in the microsecond range, and the electrical conductance of nickel sinters in the thickness direction are also considered. Mechanical problems experienced in the vibration of Ni-Cd batteries and tests to simulate cyclic fatigue of the steel table connecting the plates to the comb are considered. Methods of defining the distribution of forces when cells are compressed during battery packaging are also explored.

Gross, S.

1984-01-01

163

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 Central

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.

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

2011-01-01

164

A novel method of non-violent dissolution of sodium metal in a concentrated aqueous solution of Epsom salt  

Microsoft Academic Search

A new technique of non-violent and fast dissolution of sodium metal in a concentrated aqueous solution of Epsom salt (MgSO4.7H2O) at room temperature (RT) has been developed. The dissolution process is mildly exothermic but could be carried out even in a glass beaker in air under swift stirring condition. The reaction products consist of mixed salts of MgSO4 and Na2SO4

A. R. Lakshmanan; M. V. R. Prasad; D. Ponraju; H. Krishnan

2004-01-01

165

Measurement of pseudoephedrine hydrochloride dissolution using chloride-ion electrode.  

PubMed

Experiments were performed to determine the suitability of using a chloride-ion electrode for the measurement of pseudoephedrine hydrochloride dissolution from commercially available compressed tablets. Dissolution experiments were carried out in 500 ml of distilled water using the USP paddle method at 100 rpm. Both chloride ion and pseudoephedrine (UV spectrophotometry) were measured at six different sampling times. Percent dissolved versus time values were linearized on a log-normal probability basis. The slopes of individual lines obtained from the chloride and pseudoephedrine measurements were compared using a Student t test and did not differ significantly (t = 0.415, df = 5, p greater than 0.05). In addition to providing an efficient, inexpensive, and simple method for measuring pseudoephedrine hydrochloride dissolution rates, the chloride-ion electrode could be used in the measurement of dissolution rates for a wide variety of drugs available as hydrochloride salts. PMID:7299681

Chen, S T; Thompson, R C; Poust, R I

1981-11-01

166

Tested method to minimize plutonium assay discrepancies between laboratories  

SciTech Connect

Plutonium assay differences are frequently observed between laboratories exchanging plutonium dioxide powders. These differences are commonly the result of chemical changes and/or nonhomogeneities in sampled materials. The irregularities are often caused by moisture absorption during sampling, packaging, shipment, and storage of the materials. A method is proposed which eliminates the effects of chemical change in samples, particularly moisture absorption, and minimizes sampling error. A nondestructive thermal watts/gram test on every preweighed sampled and total dissolution of these samples for chemical assay are the primary features which make this method effective. Because this method minimizes the error related to exchange material, it is possible to design an interlaboratory exchange program which demonstrates the assay capabiliies of the participants. In an experiment performed to demonstrate the effectiveness of this method, three PuO/sub 2/ batches of varying isotopic composition were synthesized at Mound to be used in the exchange tess. Powder sample aliquots from each batch were weighed directly into their vials under controlled atmospheric conditions. Calorimetric heat measurements were made on each vial to test homogeneity and verify sample weight. Six vials of each batch were chemically assayed at Mound and six at NBL (New Brunswick Laboratory). Both laboratories chose controlled-potential coulometry as the chemical assay technique because of its demonstrated precision and accuracy. Total dissolution of preweighed exchange samples eliminated the need for laborious and usually futile heating to return the material to its original condition. The mean chemical assay values obtained by Mound and NBL agree to within 0.01% for each of the compositions tested. Testing of both chemical assay and calorimetric data revealed no sampling error throughout the experiment.

Seiler, R.J.; Goss, R.L.; Rodenburg, W.W.; Rogers, D.R.

1982-01-29

167

Design of a two-well field test to determine in-situ residual and dissolution trapping of CO2 in a deep saline aquifer  

NASA Astrophysics Data System (ADS)

CO2 trapping as immobile residual phase and by dissolution to brine are critical processes for CO2 storage security and reservoir capacity in many geological settings in consideration for geological CO2 storage. While laboratory and numerical modelling studies have provided valuable information on the topic, further field testing is critical to improve understanding of how the CO2 trapping will take place in-situ and to assess the relative importance of the different trapping mechanisms at field sites for geological storage. Given the challenge to measure fluid flow and trapping processes in kilometre-deep reservoirs with few boreholes and limited knowledge of the spatial distribution of geological parameters, the design of field tests that can accurately quantify the CO2 trapping is also challenging. Using modelling applied to the EU MUSTANG project's field testing site at Heletz, Israel, this study investigates how a two-well dipole test configuration can be used to study migration and trapping of CO2 in-situ under influence of geological heterogeneity between two boreholes. A two-well dipole test sequence for quantifying both residual and dissolution trapping of CO2 in situ is presented. The test uses a relatively small amount of injected CO2 which is monitored by a combination of hydraulic, thermal and tracer measurement techniques. Hydraulic and thermal tests are shown to be sensitive to CO2 saturation and residual trapping. Furthermore we present a novel tracer technique, employing a non-water-soluble tracer in the CO2 phase, which is used to quantify the effective in-situ dissolution rate. Our modelling results show that the combination of these measurements in the two-well dipole configuration together with a mass balance of injected and abstracted fluids constitute an effective tool for characterization of in-situ trapping of geologically stored CO2 at the field scale.

Fagerlund, F.; Niemi, A.; Bensabat, J.; Shtivelman, V.

2012-04-01

168

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

169

49 CFR 383.133 - Test methods.  

Code of Federal Regulations, 2013 CFR

...Transportation 5 2013-10-01 2013-10-01 false Test methods. 383.133 Section 383.133 Transportation...DRIVER'S LICENSE STANDARDS; REQUIREMENTS AND PENALTIES Tests § 383.133 Test methods. (a) All tests must be...

2013-10-01

170

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

Microsoft Academic Search

In soil magnetism, the magnetic parameters alone are not always sufficient to distinguish\\u000athe lithogenic from the pedogenic magnetic fractions. Sequential extraction techniques\\u000ahave therefore been incorporated into magnetic studies to constrain the environmental\\u000ainterpretation. Here we report on the dissolution behaviour of magnetite and maghemite\\u000ain the acid-ammonium oxalate method to see whether the method is suitable for specific

I. H. M. van Oorschot; M. J. Dekkers

2000-01-01

171

Evaluation of Dissolution Media Containing a Novel Synthetic Surfactant by In Vitro Testing of BCS Class II Drugs  

Microsoft Academic Search

The objective of this study was to employ a tailor-made, surface-active agent (phosphonobile acid) in the design of dissolution media that more closely reflect various luminal fluid physicochemical parameters such as buffer capacity, osmolarity, surface tension, and pH. The proposed media are simple to prepare and use, and thus can be explored for routine application. Three BCS II drugs, glimepiride,

Hitesh Jogia; Tushar Mehta; Madhabhai Patel

172

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

173

Influence of the Efavirenz Micronization on Tableting and Dissolution  

PubMed Central

The purpose of this study was to propose an analytical procedure that provides the effects of particle size and surface area on dissolution of efavirenz. Five different batches obtained by different micronization processes and with different particle size distribution and surface area were studied. The preformulation studies and dissolution curves were used to confirm the particle size distribution effect on drug solubility. No polymorphic variety or amorphization was observed in the tested batches and the particle size distribution was determined as directly responsible for the improvement of drug dissolution. The influence of the preparation process on the tablets derived from efavirenz was observed in the final dissolution result in which agglomeration, usually seen in non-lipophilic micronized material, was avoided through the use of an appropriate wet granulation method. For these reasons, micronization may represent one viable alternative for the formulation of brick dust drugs.

Pinto, Eduardo Costa; do Carmo, Flavia Almada; da Silva Honorio, Thiago; da Silva Ascencao Barros, Rita de Cassia; Castro, Helena Carla Rangel; Rodrigues, Carlos Rangel; Esteves, Valeria Sant'Anna Dantas; Rocha, Helvecio Vinicius Antunes; de Sousa, Valeria Pereira; Cabral, Lucio Mendes

2012-01-01

174

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

175

Telemetry Test Methods. Final Report.  

National Technical Information Service (NTIS)

A flexible test system is studied and proposed to provide an extensive evaluation and testing capability for telemetry products. A distributed computer controlled, modular unit test system using Computer Automated Measurement and Control (CAMAC) standard ...

J. L. Bowers D. L. Bullard T. R. Schelp

1978-01-01

176

30 CFR 27.31 - Testing methods.  

Code of Federal Regulations, 2013 CFR

...DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS METHANE-MONITORING SYSTEMS Test Requirements § 27.31 Testing methods. A methane-monitoring system shall be tested by MSHA to determine its functional...

2013-07-01

177

Dissolution of aerosol iron in the surface waters of the North Pacific and North Atlantic oceans as determined by a semicontinuous flow-through reactor method  

Microsoft Academic Search

Aerosol iron dissolution in oceanic waters is determined with a semicontinuous batch-leaching method. In this procedure, aerosol samples that were collected from the marine boundary layer were leached in an all-Teflon flow-through reaction chamber by multiple aliquots of ?40 mL 0.4 ?m filtered oceanic surface water collected using ultraclean techniques. Each aliquot of seawater is permitted to leach the aerosol

Jingfeng Wu; Robert Rember; Cathy Cahill

2007-01-01

178

Methods of Expressing Test Scores.  

ERIC Educational Resources Information Center

The simplicity of standard score systems, percentile equivalents, and their relation to the ideal normal distribution are discussed and illustrated. Standard scores are z-scores, the T-scores, College Entrance Examination Board scores, and Army General Classification Test scores. A derivative of the general standard score system is the stanine…

Seashore, Harold G.

1955-01-01

179

Multipoint dissolution specification and acceptance sampling rule based on profile modeling and principal component analysis  

Microsoft Academic Search

In dissolution testing multiple dissolution measurements at specific time points are needed in quality control when the compliance of the product requires controlled dissolution throughout the time course. The dissolution specification based on general multivariate confidence region was proposed by Chen and Tsong (8). This paper presents two alternative procedures when the dissolution profile consists of important measurements at more

Yi Tsong; Thomas Hammerstrom; James J. Chen

1997-01-01

180

Dissolution of metallic uranium and its alloys  

Microsoft Academic Search

This review focuses on dissolution\\/reaction systems capable of treating uranium metal waste to remove its pyrophoric properties.\\u000a The primary emphasis is the review of literature describing analytical and production-scale dissolution methods applied to\\u000a either uranium metal or uranium alloys. A brief summary of uranium's corrosion behavior is included since the corrosion resistance\\u000a of metals and alloys affects their dissolution behavior.

C. A. Laue; D. Gates-Anderson; T. E. Fitch

2004-01-01

181

Dissolution processes: Stuffed structures  

NASA Astrophysics Data System (ADS)

Understanding oxide dissolution processes on the molecular scale remains a challenge. A study on nanoscale oxides suggests a mechanism for dissolution that proceeds through the formation of oxygen-stuffed metastable structures.

Fenter, Paul

2012-03-01

182

How Test Organizations Adopt New Testing Practices and Methods?  

Microsoft Academic Search

Software testing process is an activity, in which the software is verified to comply with the requirements and validated to operate as intended. As software development adopts new development methods, this means also that the test processes need to be changed. In this qualitative study, we observe ten software organizations to understand how organizations develop their test processes and how

Jussi Kasurinen; Ossi Taipale; Kari Smolander

2011-01-01

183

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

184

Methods of Testing for Sleeplessness  

PubMed Central

Normal nonrandom fluctuations in daily human perfomance have been documented for years. Published research reports have shown patterns of workers' errors in reading gas meters, operators' delays in answering calls, drivers' drowsiness, sleepy locomotive engineers' automatic breaking, vehicle crashes, deaths resulting from disease, brief periods of sleep, and sleep latency in structured naps. The authors summarized these data sets and fitted them with a two-peak-per-day cosine curve derived from the population growth function used in chaos theory. Median parameters extracted from the curve fits predicted a sharp peak of sleepiness at 2:30 AM and a secondary peak at 2:30 PM. The shape of the curve was modified by a nonlinear sleep-deprivation factor. The model appeared to be biological rather than behavioral or social because it applied well to disease-related deaths. The authors also review measurement of sleepiness through electroencephalographic monitoring, self-reports, pupillography, and the Multiple Sleep Latency and the Maintenance of Wakefulness Tests.

Mitler, Merrill M.; Miller, James C.

2008-01-01

185

Dissolution of USP prednisone calibrator tablets  

Microsoft Academic Search

We investigate the effect of stirring conditions on the dissolution of United States Pharmacopoeial Convention (USP) prednisone calibrator tablets. The experiments are performed in an automated USP-II dissolution test apparatus. For this study we use a special paddle-propeller, which can be changed from an ordinary paddle to either a pulling or pushing propeller by changing the angle of the paddle

M Röst; P.-O Quist

2003-01-01

186

The WST method, a fracture mechanics test method for FRC  

Microsoft Academic Search

The applicability of the wedge-splitting test method (WST), for determining fracture properties of fibre-reinforced concrete,\\u000a is discussed. Experimental results, using the WST method, are compared with results from uniaxial tension tests (UTT) and\\u000a three-point bending tests (3PBT) for five different FRC compositions. Furthermore, for the WST method, two different specimen\\u000a sizes have been investigated. Results from this investigation demonstrate the

I. Löfgren; H. Stang; J. F. Olesen

2008-01-01

187

Brokenhearts: Dissolution of Romantic Relationships.  

ERIC Educational Resources Information Center

Results of an investigation examining the dissolution of romantic relationships are analyzed. Men and women (N=105) who had ended romantic relationships were surveyed in structured individual interviews. Commonalities and differences in respondents' perceptions of the experience were examined. Specific tests were made of a corollary to Waller's…

Meeker, F. B.; La Fong, Carl

188

PE Metrics: Background, Testing Theory, and Methods  

ERIC Educational Resources Information Center

New testing theories, concepts, and psychometric methods (e.g., item response theory, test equating, and item bank) developed during the past several decades have many advantages over previous theories and methods. In spite of their introduction to the field, they have not been fully accepted by physical educators. Further, the manner in which…

Zhu, Weimo; Rink, Judy; Placek, Judith H.; Graber, Kim C.; Fox, Connie; Fisette, Jennifer L.; Dyson, Ben; Park, Youngsik; Avery, Marybell; Franck, Marian; Raynes, De

2011-01-01

189

Methods for scaling icing test conditions  

NASA Technical Reports Server (NTRS)

This report presents the results of tests at NASA Lewis to evaluate several methods to establish suitable alternative test conditions when the test facility limits the model size or operating conditions. The first method was proposed by Olsen. It can be applied when full-size models are tested and all the desired test conditions except liquid-water content can be obtained in the facility. The other two methods discussed are: a modification of the French scaling law and the AEDC scaling method. Icing tests were made with cylinders at both reference and scaled conditions representing mixed and glaze ice in the NASA Lewis Icing Research Tunnel. Reference and scale ice shapes were compared to evaluate each method. The Olsen method was tested with liquid-water content varying from 1.3 to .8 g/m(exp3). Over this range, ice shapes produced using the Olsen method were unchanged. The modified French and AEDC methods produced scaled ice shapes which approximated the reference shapes when model size was reduced to half the reference size for the glaze-ice cases tested.

Anderson, David N.

1995-01-01

190

Transport Test Problems for Hybrid Methods Development  

Microsoft Academic Search

This report presents 9 test problems to guide testing and development of hybrid calculations for the ADVANTG code at ORNL. These test cases can be used for comparing different types of radiation transport calculations, as well as for guiding the development of variance reduction methods. Cases are drawn primarily from existing or previous calculations with a preference for cases which

Mark W. Shaver; Erin A. Miller; Richard S. Wittman; Benjamin S. McDonald

2011-01-01

191

Methods of Testing Thermal Insulation and Associated Test Apparatus  

NASA Technical Reports Server (NTRS)

The system and method for testing thermal insulation uses a cryostatic insulation tester having a vacuum chamber and a cold mass including a test chamber and upper and lower guard chambers adjacent thereto. The thermal insulation is positioned within the vacuum chamber and adjacent the cold mass. Cryogenic liquid is supplied to the test chamber, upper guard and lower guard to create a first gas layer in an upper portion of the lower guard chamber and a second gas layer in an upper portion of the test chamber. Temperature are sensed within the vacuum chamber to test the thermal insulation.

2004-01-01

192

Integrating drug permeability with dissolution profile to develop IVIVC.  

PubMed

In this review article, three different approaches to predict in vivo oral absorption based on the in vitro data of drug permeability, solubility and dissolution were introduced. At the drug discovery stage, the absorption potential of each candidate is most important to select better compounds for further development. The concept of maximum absorbable dose is applied widely, not only to evaluate the absorption potential but also to elucidate the rate-limiting process of oral absorption that helps us to understand the cause of poor absorption. To integrate the permeability of the drug with its dissolution profile, two different approaches, in vitro dissolution/permeation system (D/P system) and in silico model and simulation method, are proposed. In the D/P system, by mimicking the in vivo process of drug absorption, the permeated amount of drugs, that is the total output of dissolution and permeation processes, are correlated with the fraction absorbed in human (F(a)). This system is powerful for evaluating the improved absorption by various formulations and the effect of food intake. On the other hand, in the model and simulation approach, an intrinsic dissolution parameter of drug particle, z, was extracted from the small scale in vitro test and the process of intestinal absorption was re-constructed in silico by incorporating the physiological parameters in human. The effective use of these approaches for the development of oral drug products is discussed through various case studies. PMID:22581486

Takano, Ryusuke; Kataoka, Makoto; Yamashita, Shinji

2012-10-01

193

Dissolution of molybdenum-silicon (-boron) alloys using a mixture of sulfuric, nitric and hydrofluoric acids and a sequential correction method for ICP-AES analysis.  

PubMed

For the major component analysis of Mo-Si (-B) alloys by ICP-AES, an appropriate dissolution method is necessary. The general procedure using a HNO3-HF mixture cannot be applied for Mo-Si (-B) alloys due to Si volatilization followed by violent reaction and due to MoO2 precipitation in the preparation of a Mo standard solution from metallic Mo. Good results were obtained with a mixture of 10 mL H2SO4, 1 mL HNO3, 2 mL HF and 12 mL H2O for Mo-Si (-B) alloys. The samples were completely dissolved at room temperature without any losses. A sequential correction method is also suggested to correct several errors in ICP-AES analysis such as fluctuation in the emission intensities, spectral interferences, non-spectral interferences and blank values. PMID:11225363

Danzaki, Y; Wagatsuma, K; Syoji, T; Yoshimi, K

2001-01-01

194

Pharmaceutical compositions with improved dissolution  

US Patent & Trademark Office Database

The invention relates to methods of screening mixtures containing a pharmaceutical compound and an excipient to identify properties of the pharmaceutical compound/excipient combination that retard solid-state nucleation. The invention further relates to increasing the solubility, dissolution and bioavailability of a drug with low solubility in gastric fluids conditions by combining the drug with a precipitation retardant and an optional enhancer.

2013-01-29

195

Method and apparatus for testing microfilaments  

DOEpatents

A method and apparatus are disclosed for testing tensile strength of microfilaments. Fibers as small as 0.001 inch in diameter and 0.04 inches in length have been tested, although the method and apparatus of the invention are capable of testing fibers of smaller diameter and length. The invention utilizes a method wherein one or both ends of a microfilament is gripped using resin which is softened sufficiently to accept an end of the microfilament and then allowed to harden. The invention also employs the use of a translation stage capable of controlled three-dimensional movement suited to facilitating gripping of the microfilament.

Schleitweiler, Patrick M. (Dayton, OH); Merten, Jr., Charles W. (West Carrollton, OH)

1995-08-01

196

Method and apparatus for testing microfilaments  

DOEpatents

A method and apparatus are disclosed for testing tensile strength of microfilaments. Fibers as small as 0.001 inch in diameter and 0.04 inches in length have been tested, although the method and apparatus of the invention are capable of testing fibers of smaller diameter and length. The invention utilizes a method wherein one or both ends of a microfilament is gripped using resin which is softened sufficiently to accept an end of the microfilament and then allowed to harden. The invention also employs the use of a translation stage capable of controlled three-dimensional movement suited to facilitating gripping of the microfilament. 2 figs.

Schleitweiler, P.M.; Merten, C.W. Jr.

1995-08-01

197

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

National Technical Information Service (NTIS)

In this report, we summarize the results of our single-pass flow-through (SPFT) tests on titanate ceramics at Pacific Northwest National Laboratory. These titanate ceramics are candidate disposal forms for excess weapons plutonium that is obligated by tre...

J. P. Icenhower D. M. Strachan M. M. Lindberg E. A. Rodriguez J. L. Steele

2003-01-01

198

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

199

30 CFR 36.41 - Testing methods.  

Code of Federal Regulations, 2013 CFR

... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT...Requirements § 36.41 Testing methods. Mobile diesel-powered transportation...

2013-07-01

200

Dental Highspeed Handpieces: A Test Method.  

National Technical Information Service (NTIS)

This study included the development of a test method for the evaluation of the performance characteristics of dental highspeed handpieces. The areas that were evaluated were power, noise, vibration, chuck concentricity, chuck retention, air consumption, c...

C. D. Foster J. M. Powell J. M. Young T. D. Stockman

1984-01-01

201

Elastomeric Bridge Bearings: Recommended Test Methods.  

National Technical Information Service (NTIS)

This report contains the findings of a study undertaken to develop performance-related specifications for elastomeric bridge bearings. The report includes recommended specifications and three new test methods for evaluating essential properties of elastom...

J. Yura A. Kumar A. Yakut C. Topkaya

2001-01-01

202

A Method for Choosing Meaningful Test Areas.  

National Technical Information Service (NTIS)

This paper deals with the problem of choosing meaningful test areas for environmental studies. It examines the concept of areal differentiation. It utilizes the unit area method of classifying phenomena and applies this concept to the separate categories ...

T. M. Griffiths

1964-01-01

203

[Simulation of bioequivalence study on the base of dissolution curves].  

PubMed

A computer method based on the in vitro dissolution of drug preparations has been elaborated for the estimation of bioequivalence. The method generates a "dissolutaion surface" from the parameters of time (X-axis), from pH (Y-axis) and from the dissolved amount (A) in % of the drug. This dissolution surface allows the determination of the general dissolution curve of the test and reference preparations. By supposing that the absorption rate constant is known from the literature, the change of the amount of dissolved drug as the function of time can be determined. On the base of this function the maximum amount of the dissolved drug in the gastrointestinal tract and the AUC can be calculated. and the test/reference ratio can be determined. In the case of linear pharmacokinetics these ratios are identical to the ratios of parameters that can be calculated in the circulation. By generating parameters between the allowed biological limits the dissolved drug-time curves of "volunteers" in the necessary number are created with the randomly generated "residence times" and their confidence intervals can be determined, i.e., on the base of dissolution curves bioequivalence can be estimated. PMID:22870777

Grezál, Gyula; Vereczkey, László

2012-01-01

204

Determination of cadmium bioaccessibility in herbal medicines and safety assessment by in vitro dissolution and ICP-AES  

Microsoft Academic Search

A method was developed for in vitro dissolution and ICP-AES based determination of cadmium (Cd) for evaluating its bioaccessibility\\u000a in herbal medicines to investigate the utility of this test for toxicological assessments. The bioaccessible Cd content of\\u000a five commonly consumed and Cd-accumulating herbal medicines was determined by in vitro dissolution test with a biorelevant\\u000a medium simulating gastric conditions. Cd levels

Dong-Hyug Yang; Young-Joo Lee

2009-01-01

205

Cathodic Delamination Accelerated Life Test Method.  

National Technical Information Service (NTIS)

A method for conducting an accelerated life test of a polymer coated metallic sample includes placing the sample below the water surface in a test tank containing water and an oxygen containing gas. Cathodic polarization of the metallic portion of the sam...

T. S. Ramotowski

2007-01-01

206

A method for testing small shipmodels  

Microsoft Academic Search

In a small tank there are possibilities for testing only small models (length of 1-2 m). They are engaged to measure the resis- tance of the ship, but self propulsion tests cannot be performed because the dimensions of the propeller are too small. This pa- per proposes a method for determining the mutual influence of ship body and propeller without

Zoltán Benedek

2008-01-01

207

YUCCA Mountain Project - Argonne National Laboratory, Annual Progress Report, FY 1997 for activity WP 1221 unsaturated drip condition testing of spent fuel and unsaturated dissolution tests of glass.  

SciTech Connect

This document reports on the work done by the Nuclear Waste Management Section of the Chemical Technology Division of Argonne National Laboratory in the period of October 1996 through September 1997. Studies have been performed to evaluate the behavior of nuclear waste glass and spent fuel samples under the unsaturated conditions (low-volume water contact) that are likely to exist in the Yucca Mountain environment being considered as a potential site for a high-level waste repository. Tests with actinide-doped waste glasses, in progress for over 11 years, indicate that the transuranic element release is dominated by colloids that continuously form and span from the glass surface. The nature of the colloids that form in the glass and spent fuel testing programs is being investigated by dynamic light scattering to determine the size distribution, by autoradiography to determine the chemistry, and by zeta potential to measure the electrical properties of the colloids. Tests with UO{sub 2} have been ongoing for 12 years. They show that the oxidation of UO{sub 2} occurs rapidly, and the resulting paragenetic sequence of secondary phases forming on the sample surface is similar to that observed for uranium found in natural oxidizing environments. The reaction of spent fuel samples in conditions similar to those used with UO{sub 2} have been in progress for over six years, and the results suggest that spent fuel forms many of the same alteration products as UO{sub 2}. With spent fuel, the bulk of the reaction occurs via a through-grain reaction process, although grain boundary attack is sufficient to have reacted all of the grain boundary regions in the samples. New test methods are under development to evaluate the behavior of spent fuel samples with intact cladding: the rate at which alteration and radionuclide release occurs when water penetrates fuel sections and whether the reaction causes the cladding to split. Alteration phases have been formed on fine grains of UO{sub 2} in contact with small volumes of water within a several month period when the radiolysis product H{sub 2}O{sub 2} is added to the groundwater solution. The test setup has been mocked up for operation with spent fuel in the hot-cell.

Bates, J. K.; Buck, E. C.; Emery, J. W.; Finch, R. J.; Finn, P. A.; Fortner, J.; Hoh, J. C.; Mertz, C.; Neimark, L. A.; Wolf, S. F.; Wronkiewicz, D. J.

1998-09-18

208

Evolution of a physiological pH 6.8 bicarbonate buffer system: Application to the dissolution testing of enteric coated products  

Microsoft Academic Search

The use of compendial pH6.8 phosphate buffer to assess dissolution of enteric coated products gives rise to poor in vitro–in vivo correlations because of the inadequacy of the buffer to resemble small intestinal fluids. A more representative and physiological medium, pH6.8 bicarbonate buffer, was developed to evaluate the dissolution behaviour of enteric coatings. The bicarbonate system was evolved from pH7.4

Fang Liu; Hamid A. Merchant; Rucha P. Kulkarni; Maram Alkademi; Abdul W. Basit

2011-01-01

209

Alternative Test Methods for Electronic Parts  

NASA Technical Reports Server (NTRS)

It is common practice within NASA to test electronic parts at the manufacturing lot level to demonstrate, statistically, that parts from the lot tested will not fail in service using generic application conditions. The test methods and the generic application conditions used have been developed over the years through cooperation between NASA, DoD, and industry in order to establish a common set of standard practices. These common practices, found in MIL-STD-883, MIL-STD-750, military part specifications, EEE-INST-002, and other guidelines are preferred because they are considered to be effective and repeatable and their results are usually straightforward to interpret. These practices can sometimes be unavailable to some NASA projects due to special application conditions that must be addressed, such as schedule constraints, cost constraints, logistical constraints, or advances in the technology that make the historical standards an inappropriate choice for establishing part performance and reliability. Alternate methods have begun to emerge and to be used by NASA programs to test parts individually or as part of a system, especially when standard lot tests cannot be applied. Four alternate screening methods will be discussed in this paper: Highly accelerated life test (HALT), forward voltage drop tests for evaluating wire-bond integrity, burn-in options during or after highly accelerated stress test (HAST), and board-level qualification.

Plante, Jeannette

2004-01-01

210

Incongruent dissolution and surface area of kaolinite  

SciTech Connect

The surface of kaolinite is modeled as a combination of Al and Si surface sites in order to understand its aqueous dissolution behavior. The pH dependence of the initial nonstoichiometric dissolution of kaolinite at 25 C can be related to the pH dependence of protonation and deprotonation of the surface Si and Al sites. The analysis indicates Al dissolution rates are greater than Si at pH < 4 with Si dissolution rate greater than Al at 4 < pH < 11 and initial stoichiometric dissolution at pH > 11. An analysis of the surface site density of kaolinite from surface potentiometric titration data is presented. This indicates that the surface area of kaolinite and possibly other clay minerals available for forming surface complexes and sites for cation detachment is significantly larger than that measured by standard gas adsorption methods. It is believed that H[sup +] and OH[sup [minus

Xie, Z.; Walther, J.V. (Northwestern Univ., Evanston, IL (United States))

1992-09-01

211

Boehmite Actual Waste Dissolutions Studies  

SciTech Connect

The U.S. Department of Energy plans to vitrify approximately 60,000 metric tons of high-level waste (HLW) sludge from underground storage tanks at the Hanford Nuclear Reservation. To reduce the volume of HLW requiring treatment, a goal has been set to remove a significant quantity of the aluminum, which comprises nearly 70 percent of the sludge. Aluminum is found in the form of gibbsite, sodium aluminate and boehmite. Gibbsite and sodium aluminate can be easily dissolved by washing the waste stream with caustic. Boehmite, which comprises nearly half of the total aluminum, is more resistant to caustic dissolution and requires higher treatment temperatures and hydroxide concentrations. Samples were taken from four Hanford tanks and homogenized in order to give a sample that is representative of REDOX (Reduction Oxidation process for Pu recovery) sludge solids. Bench scale testing was performed on the homogenized waste to study the dissolution of boehmite. Dissolution was studied at three different hydroxide concentrations, with each concentration being run at three different temperatures. Samples were taken periodically over the 170 hour runs in order to determine leaching kinetics. Results of the dissolution studies and implications for the proposed processing of these wastes will be discussed.

Snow, Lanee A.; Lumetta, Gregg J.; Fiskum, Sandra K.; Peterson, Reid A.

2008-07-15

212

Formal methods for test case generation  

NASA Technical Reports Server (NTRS)

The invention relates to the use of model checkers to generate efficient test sets for hardware and software systems. The method provides for extending existing tests to reach new coverage targets; searching *to* some or all of the uncovered targets in parallel; searching in parallel *from* some or all of the states reached in previous tests; and slicing the model relative to the current set of coverage targets. The invention provides efficient test case generation and test set formation. Deep regions of the state space can be reached within allotted time and memory. The approach has been applied to use of the model checkers of SRI's SAL system and to model-based designs developed in Stateflow. Stateflow models achieving complete state and transition coverage in a single test case are reported.

Rushby, John (Inventor); De Moura, Leonardo Mendonga (Inventor); Hamon, Gregoire (Inventor)

2011-01-01

213

Development and validation of dissolution study of sustained release dextromethorphan hydrobromide tablets.  

PubMed

This study describes the development and validation of dissolution tests for sustained release Dextromethorphan hydrobromide tablets using an HPLC method. Chromatographic separation was achieved on a C18 column utilizing 0.5% triethylamine (pH 7.5) and acetonitrile in the ratio of 50:50. The detection wavelength was 280 nm. The method was validated and response was found to be linear in the drug concentration range of 10-80 microg mL(-1). The suitable conditions were clearly decided after testing sink conditions, dissolution medium and agitation intensity. The most excellent dissolution conditions tested, for the Dextromethorphan hydrobromide was applied to appraise the dissolution profiles. The method was validated and response was found to be linear in the drug concentration range of 10-80 microg mL(-1). The method was established to have sufficient intermediate precision as similar separation was achieved on another instrument handled by different operators. Mean Recovery was 101.82%. Intra precisions for three different concentrations were 1.23, 1.10 0.72 and 1.57, 1.69, 0.95 and inter run precisions were % RSD 0.83, 1.36 and 1.57%, respectively. The method was successfully applied for dissolution study of the developed Dextromethorphan hydrobromide tablets. PMID:24897800

Rajan, Sekar; Colaco, Socorrina; Ramesh, N; Meyyanathan, Subramania Nainar; Elango, K

2014-02-01

214

Standard Test Methods for Textile Composites  

NASA Technical Reports Server (NTRS)

Standard testing methods for composite laminates reinforced with continuous networks of braided, woven, or stitched fibers have been evaluated. The microstructure of these textile' composite materials differs significantly from that of tape laminates. Consequently, specimen dimensions and loading methods developed for tape type composites may not be applicable to textile composites. To this end, a series of evaluations were made comparing testing practices currently used in the composite industry. Information was gathered from a variety of sources and analyzed to establish a series of recommended test methods for textile composites. The current practices established for laminated composite materials by ASTM and the MIL-HDBK-17 Committee were considered. This document provides recommended test methods for determining both in-plane and out-of-plane properties. Specifically, test methods are suggested for: unnotched tension and compression; open and filled hole tension; open hole compression; bolt bearing; and interlaminar tension. A detailed description of the material architectures evaluated is also provided, as is a recommended instrumentation practice.

Masters, John E.; Portanova, Marc A.

1996-01-01

215

Synthesis and characterization of [BMIM]bromide using microwave-assisted organic synthesis method and its application for dissolution of palm empty fruit bunch  

NASA Astrophysics Data System (ADS)

The decrease of cellulose crystallinity index of palm empty fruit bunch is crucial for the next application of cellulose as raw material for various biofuel and its derivatives. The aim of this research is to decrease the cellulose crystallinity index of palm empty fruit bunch using 1-butyl-3-methylimidazoliumbromide or [BMIM] bromide which has been synthesized using Microwave-Assisted Organic Synthesis (MAOS) method. Conventional reaction method has also been carried out to synthesize [BMIM]bromide for comparison as well. The characterization of synthesized product using FTIR, 1H-NMR, 13C-NMR and LC-MS showed that these reactions have been carried out successfully. The results showed that MAOS method is up to 90% faster in producing [BMIM]bromide compare to the conventional method. The application of [BMIM]bromide for dissolution of palm empty fruit bunch showed that cellulose and lignin could be extracted using stirring process for 20 hours. The decrease of cellulose crystallinity index and its morphology changes were identified using FTIR and Scanning Electron Microscope.

Arianie, Lucy; Wahyuningrum, Deana; Nurrachman, Zeily; Natalia, Dessy

2014-03-01

216

Development of test methods for textile composites  

NASA Technical Reports Server (NTRS)

NASA's Advanced Composite Technology (ACT) Program was initiated in 1990 with the purpose of developing less costly composite aircraft structures. A number of innovative materials and processes were evaluated as a part of this effort. Chief among them are composite materials reinforced with textile preforms. These new forms of composite materials bring with them potential testing problems. Methods currently in practice were developed over the years for composite materials made from prepreg tape or simple 2-D woven fabrics. A wide variety of 2-D and 3-D braided, woven, stitched, and knit preforms were suggested for application in the ACT program. The applicability of existing test methods to the wide range of emerging materials bears investigation. The overriding concern is that the values measured are accurate representations of the true material response. The ultimate objective of this work is to establish a set of test methods to evaluate the textile composites developed for the ACT Program.

Masters, John E.; Ifju, Peter G.; Fedro, Mark J.

1993-01-01

217

The dilemma of disappearing diatoms: Incorporating diatom dissolution data into palaeoenvironmental modelling and reconstruction  

NASA Astrophysics Data System (ADS)

Taphonomic issues pose fundamental challenges for Quaternary scientists to recover environmental signals from biological proxies and make accurate inferences of past environments. The problem of microfossil preservation, specifically diatom dissolution, remains an important, but often overlooked, source of error in both qualitative and quantitative reconstructions of key variables from fossil samples, especially those using relative abundance data. A first step to tackling this complex issue is establishing an objective method of assessing preservation (here, diatom dissolution) that can be applied by different analysts and incorporated into routine counting strategies. Here, we establish a methodology for assessment of diatom dissolution under standard light microscopy (LM) illustrated with morphological criteria for a range of major diatom valve shapes. Dissolution data can be applied to numerical models (transfer functions) from contemporary samples, and to fossil material to aid interpretation of stratigraphic profiles and taphonomic pathways of individual taxa. Using a surface sediment diatom-salinity training set from the Northern Great Plains (NGP) as an example, we explore a variety of approaches to include dissolution data in salinity inference models indirectly and directly. Results show that dissolution data can improve models, with apparent dissolution-adjusted error (RMSE) up to 15% lower than their unadjusted counterparts. Internal validation suggests improvements are more modest, with bootstrapped prediction errors (RMSEP) up to 10% lower. When tested on a short core from Devils Lake, North Dakota, which has a historical record of salinity, dissolution-adjusted models infer higher values compared to unadjusted models during peak salinity of the 1930s-1940s Dust Bowl but nonetheless significantly underestimate peak values. Site-specific factors at Devils Lake associated with effects of lake level change on taphonomy (preservation and re-working, implied by dissolution data) may override model improvements incorporating dissolution. Dissolution-adjusted salinity models are also applied to a 150-year sediment record from Spiritwood Lake, North Dakota, which suggests that this lake has a damped and lagged response to major regional climate forcing of salinity during the Dust Bowl. At this site, dissolution data also suggest different taphonomic behaviour of taxa related to their seasonal patterns of growth and sedimentation. Thus, dissolution data can improve models, and aid interpretation of sedimentary profiles as records of limnological, ecological and environmental change, filtered by taphonomy.

Ryves, David B.; Battarbee, Richard W.; Fritz, Sherilyn C.

2009-01-01

218

Modeling dissolution in aluminum alloys  

NASA Astrophysics Data System (ADS)

Aluminum and its alloys are used in many aspects of modern life, from soda cans and household foil to the automobiles and aircraft in which we travel. Aluminum alloy systems are characterized by good workability that enables these alloys to be economically rolled, extruded, or forged into useful shapes. Mechanical properties such as strength are altered significantly with cold working, annealing, precipitation-hardening, and/or heat-treatments. Heat-treatable aluminum alloys contain one or more soluble constituents such as copper, lithium, magnesium, silicon and zinc that individually, or with other elements, can form phases that strengthen the alloy. Microstructure development is highly dependent on all of the processing steps the alloy experiences. Ultimately, the macroscopic properties of the alloy depend strongly on the microstructure. Therefore, a quantitative understanding of the microstructural changes that occur during thermal and mechanical processing is fundamental to predicting alloy properties. In particular, the microstructure becomes more homogeneous and secondary phases are dissolved during thermal treatments. Robust physical models for the kinetics of particle dissolution are necessary to predict the most efficient thermal treatment. A general dissolution model for multi-component alloys has been developed using the front-tracking method to study the dissolution of precipitates in an aluminum alloy matrix. This technique is applicable to any alloy system, provided thermodynamic and diffusion data are available. Treatment of the precipitate interface is explored using two techniques: the immersed-boundary method and a new technique, termed here the "sharp-interface" method. The sharp-interface technique is based on a variation of the ghost fluid method and eliminates the need for corrective source terms in the characteristic equations. In addition, the sharp-interface method is shown to predict the dissolution behavior of precipitates in aluminum alloys when compared with published experimental results. The influence of inter-particle spacing is examined and shown to have a significant effect on dissolution kinetics. Finally, the impact of multiple particles of various sizes interacting in an aluminum matrix is investigated. It is shown that smaller particles dissolve faster, as expected, but influence the dissolution of larger particles through soft-impingement, even after the smaller particles have disappeared.

Durbin, Tracie Lee

219

Nondestructive test method accurately sorts mixed bolts  

NASA Technical Reports Server (NTRS)

Neutron activation analysis method sorts copper plated steel bolts from nickel plated steel bolts. Copper and nickel plated steel bolt specimens of the same configuration are irradiated with thermal neutrons in a test reactor for a short time. After thermal neutron irradiation, the bolts are analyzed using scintillation energy readout equipment.

Dezeih, C. J.

1966-01-01

220

Properties and Test Methods for Energy Peat.  

National Technical Information Service (NTIS)

The aim of the project SVEFIN TORV is to provide a collected picture of the properties of Swedish and Finnish industrial peat. Methods are available to test and analyze industrial peat for the variables which characterize its commercial value as fuel (cal...

G. Blomqvist D. Fredriksson R. Thun

1984-01-01

221

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 ...

222

Method for non-destructive testing  

SciTech Connect

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

223

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 example,…

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

2013-01-01

224

Dissolution properties of different designed and formulated salbutamol tablet dosage forms.  

PubMed

Pharmaceutical availability or in vitro availability is one of the aspects of drug bioavailability. Dissolution can be described best as a tool that can provide valuable information about the availability of a drug product. Dissolution test was performed on three different designed and formulated of salbutamol tablet formulations marketed in Turkey. The test methods were the paddle method and the rotating basket method described in United States Pharmacopeia. All studied formulations showed a good agreement with pharmacopeial requirements. In particular all studied commercial tablet formulations showed a quite fast release of the antiasthmatic drug. Other type of table formulations showed slow release. In order to evaluate the dissolution rates five different kinetics have been examined and the best fitting kinetics was found to be RRSBW kinetic. PMID:11126615

Ozkan, Y; Sava?er, A; Ozalp, Y; I?imer, A

2000-01-01

225

Real-time dissolution behavior of furosemide in biorelevant media as determined by UV imaging.  

PubMed

The potential of UV imaging as a new small scale flow-through dissolution testing platform and its ability to incorporate biorelevant media was tested. Furosemide was utilized as a model poorly soluble drug, and dissolution media simulating conditions in the small intestine (5/1.25?mM and 40/10?mM bile salt/phospholipid, pH 6.5) together with corresponding blank buffer were employed. Dissolution rates as a function of flow rate (0.2-1.0?mL/min) were determined directly from UV images, and by analysis of collected effluent using UV spectrophotometry. A good agreement in dissolution rates was observed, however repeatability of data based on measurement of collected effluent was superior to that obtained by UV imaging in the utilized prototypic flow cell. Both methods indicated that biorelevant media did not markedly increase the dissolution rate of furosemide as compared to buffer. Qualitatively, UV images indicated that uncontrolled swelling/precipitation of furosemide on the compact surface was occurring in some samples. In situ Raman spectroscopy together with X-ray diffraction analysis confirmed that the observations were not due to a solid form transformation of furosemide. The presented results highlight the complementary features of the utilized techniques and, in particular, the detailed information related to dissolution behavior which can be achieved by UV imaging. PMID:23136844

Gordon, Sarah; Naelapää, Kaisa; Rantanen, Jukka; Selen, Arzu; Müllertz, Anette; Østergaard, Jesper

2013-01-01

226

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

227

Orthogonal array design as a chemometric method for the optimization of analytical procedures. Part 5. Three-level design and its application in microwave dissolution of biological samples.  

PubMed

The theory and methodology of a three-level orthogonal array design as a chemometric method for the optimization of analytical procedures were developed. In the theoretical section, firstly, the matrix of a three-level orthogonal array design is described and orthogonality is proved by a quadratic regression model. Next, the assignment of experiments in a three-level orthogonal array design and the use of the triangular table associated with the corresponding orthogonal array matrix are illustrated, followed by the data analysis strategy, in which significance of the different factor effects is quantitatively evaluated by the analysis of variance (ANOVA) technique and the percentage contribution method. Then, a quadratic regression equation representing the response surface is established to estimate each factor that has a significant influence. Finally, on the basis of the quadratic regression equation established, the derivative algorithm is used to find the optimum value for each variable considered. In the application section, microwave dissolution for the determination of selenium in biological samples by hydride generation atomic absorption spectrometry is employed, as a practical example, to demonstrate the application of the proposed three-level orthogonal array design in analytical chemistry. PMID:7771675

Lan, W G; Wong, M K; Chen, N; Sin, Y M

1995-04-01

228

[Process monitoring of dissolution of valsartan and hydrochlorothiazide tablets by fiber-chemical sensor assisted by mathematical separation model of linear equations].  

PubMed

A method for on-line monitoring the dissolution of Valsartan and hydrochlorothiazide tablets assisted by mathematical separation model of linear equations was established. UV spectrums of valsartan and hydrochlorothiazide were overlapping completely at the maximum absorption wavelength respectively. According to the Beer-Lambert principle of absorbance additivity, the absorptivity of Valsartan and hydrochlorothiazide was determined at the maximum absorption wavelength, and the dissolubility of Valsartan and hydrochlorothiazide tablets was detected by fiber-optic dissolution test (FODT) assisted by the mathematical separation model of linear equations and compared with the HPLC method. Results show that two ingredients were real-time determined simultaneously in given medium. There was no significant difference for FODT compared with HPLC (p > 0.05). Due to the dissolution behavior consistency, the preparation process of different batches was stable and with good uniformity. The dissolution curves of valsartan were faster and higher than hydrochlorothiazide. The dissolutions at 30 min of Valsartan and hydrochlorothiazide were concordant with US Pharmacopoeia. It was concluded that fiber-optic dissolution test system assisted by the mathematical separation model of linear equations that can detect the dissolubility of Valsartan and hydrochlorothiazide simultaneously, and get dissolution profiles and overall data, which can directly reflect the dissolution speed at each time. It can provide the basis for establishing standards of the drug. Compared to HPLC method with one-point data, there are obvious advantages to evaluate and analyze quality of sampling drug by FODT. PMID:25007628

Ding, Hai-Yan; Li, Gai-Ru; Yu, Ying-Ge; Guo, Wei; Zhi, Ling; Li, Xin-Xia

2014-04-01

229

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

230

Precipitation and Dissolution Potentials  

Microsoft Academic Search

Precipitation and dissolution potentials for KCl, NaCl, BaCl2, and NH4Cl have been measured with a Lindemann electrometer both in air as well as in nitrogen. The values in the latter case are lower. The electrode on which precipitation and dissolution takes place is found to be negative. The available evidence shows that static potential is developed. In order to assess

R. P. Rastogi; R. D. Shukla

1970-01-01

231

Methods and instruments for materials testing  

NASA Technical Reports Server (NTRS)

Methods and instruments for characterizing a material, such as the properties of bone in a living human subject, using a test probe constructed for insertion into the material and a reference probe aligned with the test probe in a housing. The housing is hand held or placed so that the reference probe contacts the surface of the material under pressure applied either by hand or by the weight of the housing. The test probe is inserted into the material to indent the material while maintaining the reference probe substantially under the hand pressure or weight of the housing allowing evaluation of a property of the material related to indentation of the material by the probe. Force can be generated by a voice coil in a magnet structure to the end of which the test probe is connected and supported in the magnet structure by a flexure, opposing flexures, a linear translation stage, or a linear bearing. Optionally, a measurement unit containing the test probe and reference probe is connected to a base unit with a wireless connection, allowing in the field material testing.

Hansma, Paul (Inventor); Drake, Barney (Inventor); Rehn, Douglas (Inventor); Adams, Jonathan (Inventor); Lulejian, Jason (Inventor)

2011-01-01

232

Calcite saturation, foraminiferal test mass, and Mg/Ca-based temperatures dissolution corrected using XDX—A 150 ka record from the western Indian Ocean  

NASA Astrophysics Data System (ADS)

record of deep-sea calcite saturation >(?>[CO 32->]>), derived from X-ray computed tomography-based foraminifer dissolution index, XDX, was constructed for the past 150 ka for a core from the deep (4157 m) tropical western Indian Ocean. G. sacculifer and N. dutertrei recorded a similar dissolution history, consistent with the process of calcite compensation. Peaks in calcite saturation (˜15 µmol/kg higher than the present-day value) occurred during deglaciations and early in MIS 3. Dissolution maxima coincided with transitions to colder stages. The mass record of G. sacculifer better indicated preservation than did that of N. dutertrei or G. ruber. Dissolution-corrected Mg/Ca-derived SST records, like other SST records from marginal Indian Ocean sites, showed coolest temperatures of the last 150 ka in early MIS 3, when mixed layer temperatures were ˜4°C lower than present SST. Temperatures recorded by N. dutertrei showed the thermocline to be ˜4°C colder in MIS 3 compared to the Holocene (8 ka B.P.).

Johnstone, Heather J. H.; Kiefer, Thorsten; Elderfield, Henry; Schulz, Michael

2014-03-01

233

The effect of calcination temperature on the microstructure and photocatalytic activity of TiO2-based composite nanotubes prepared by an in situ template dissolution method  

NASA Astrophysics Data System (ADS)

TiO2-based composite nanotubes, based on an in situ template dissolution method, were one-step fabricated in a mixed aqueous solution of ammonium hexafluorotitanate and boric acid using ZnO nanorods as templates, and then the samples were calcined at different temperatures. The photocatalytic activity of the samples was evaluated by photocatalytic decoloration of Methyl Orange (MO) aqueous solution at ambient temperature under UV light. The results showed that the prepared sample possessed nanoscale tubular morphology with a wall thickness of ca. 30-50 nm, inner diameters of ca. 50-150 nm and lengths of ca. 400-2000 nm. The calcined samples exhibited excellent stabilization of the anatase phase in a wide temperature range of 300-800 °C. The un-calcined and calcined samples possessed hierarchically macro-mesoporous structures. The sample calcined at 600 °C exhibited the highest photocatalytic activity, corresponding to the maximal formation rate of \\z.rad OH on the photocatalyst. This is attributed to the improvement of anatase TiO2 crystallization, the formation of multi-phase structures including anatase, cubic Zn2TiO4, hexagonal ZnTiO3 and cubic ZnTiO3, and the presence of hierarchically macro-mesoporous structures.

Fan, Jiajie; Zhao, Li; Yu, Jiaguo; Liu, Gang

2012-09-01

234

Testing Photometric Methods in the Euclid Testbed  

NASA Astrophysics Data System (ADS)

The Euclid satellite will investigate the distance-redshift relationship and the evolution of cosmic structures by measuring shapes and redshifts of galaxies and clusters of galaxies. The various Euclid experiments require very accurate object photometry in order to achieve its science goals. Building upon our experience in the Dark Energy Survey data management, we have developed the Euclid Testbed which allows one to compare different methods for various data processing steps such as object detection and object photometry. Our first target is testing photometric methods that are based on measurements taken on the ensemble of single images and not on co-added images. In this contribution we present and discuss the structure of the Euclid Testbed. We introduce our own single image photometry software FitPhot, and give a detailed comparison of its accuracy with other photometric methods/software.

Kümmel, M.; Mohr, J.; Desai, S.; Henderson, R.; Koppenhoefer, J.; Paech, K.; Wetzstein, M.

2014-05-01

235

Testing methods and techniques: A compilation  

NASA Technical Reports Server (NTRS)

Mechanical testing techniques, electrical and electronics testing techniques, thermal testing techniques, and optical testing techniques are the subject of the compilation which provides technical information and illustrations of advanced testing devices. Patent information is included where applicable.

1974-01-01

236

Veriflow Campylobacter. Performance tested method 101201.  

PubMed

Veriflow Campylobacter is a molecular based assay for the presumptive and qualitative detection of the most common occurring foodborne Campylobacter species: C. jejuni and C. coli. The assay utilizes a PCR detection method coupled with a rapid, visual, flow-based assay that develops in 3 min post PCR amplification and requires only 24 h of non-specialized enrichment for maximum sensitivity. The Veriflow Campylobacter system eliminates the need for microaerobic chambers, gel electrophoresis or fluorophore based detection of target amplification, and does not require complex data analysis. This Performance Tested Method validation study demonstrated the ability of the Veriflow method to detect naturally occurring Campylobacterfrom chicken carcass rinsates. In the reference comparison study, Chi-square and probability of detection analyses of two unpaired studies indicated that there was no significant difference between the Veriflow Campylobacter method and the U.S. Department of Agriculture (USDA)/Food Safety and Inspection Service (FSIS) reference method. There was no indication of false positive or false negative detection in the reference comparison study, and all 50 C. jejuni and C. coli strains were detected, while 35 nonspecific organisms were undetected in the exclusivity/ inclusivity study. The study results show that Veriflow Campylobacter is a sensitive, selective and robust assay for the detection of C. jejuni and C. coli in chicken carcass rinsates. PMID:25051630

Joelsson, Adam C; Brown, Ashley S; Puri, Amrita; Keough, Martin P; Pascal, Benjamin J; Gaudioso, Zara E

2014-01-01

237

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

238

Evolution of a physiological pH 6.8 bicarbonate buffer system: application to the dissolution testing of enteric coated products.  

PubMed

The use of compendial pH 6.8 phosphate buffer to assess dissolution of enteric coated products gives rise to poor in vitro-in vivo correlations because of the inadequacy of the buffer to resemble small intestinal fluids. A more representative and physiological medium, pH 6.8 bicarbonate buffer, was developed to evaluate the dissolution behaviour of enteric coatings. The bicarbonate system was evolved from pH7.4 Hanks balanced salt solution to produce a pH 6.8 bicarbonate buffer (modified Hanks buffer, mHanks), which resembles the ionic composition and buffer capacity of intestinal milieu. Prednisolone tablets were coated with a range of enteric polymers: hypromellose phthalate (HP-50 and HP-55), cellulose acetate phthalate (CAP), hypromellose acetate succinate (HPMCAS-LF and HPMCAS-MF), methacrylic acid copolymers (EUDRAGIT® L100-55, EUDRAGIT® L30D-55 and EUDRAGIT® L100) and polyvinyl acetate phthalate (PVAP). Dissolution of coated tablets was carried out using USP-II apparatus in 0.1M HCl for 2h followed by pH 6.8 phosphate buffer or pH 6.8 mHanks bicarbonate buffer. In pH 6.8 phosphate buffer, the various enteric polymer coated products displayed rapid and comparable dissolution profiles. In pH 6.8 mHanks buffer, drug release was delayed and marked differences were observed between the various coated tablets, which is comparable to the delayed disintegration times reported in the literature for enteric coated products in the human small intestine. In summary, the use of pH 6.8 physiological bicarbonate buffer (mHanks) provides more realistic and discriminative in vitro release assessment of enteric coated formulations compared to compendial phosphate buffer. PMID:21255647

Liu, Fang; Merchant, Hamid A; Kulkarni, Rucha P; Alkademi, Maram; Basit, Abdul W

2011-05-01

239

Seismic methods for verifying nuclear test bans  

NASA Astrophysics Data System (ADS)

Seismological research of the past 25 years related to verification of a Threshold Test Ban Treaty (TIBT) indicates that a treaty banning nuclear weapons tests in all environments, including underground explosions, can be monitored with high reliablility down to explosions of very small size (about one kiloton). There would be high probability of successful identification of explosions of that size even if elaborate measures were taken to evade detection. Seismology provides the principal means of detecting, locating and identifying underground explosions and of determining their yields. We discuss a number of methods for identifying detected seismic events as being either explosions or earthquakes including the event's location, depth and spectral character. The seismic waves generated by these two types of sources differ in a number of fundamental ways that can be utilized for identification or discrimination. All of the long-standing issues related to a comprehensive treaty were resolved in principle (and in may cases in detail) in negotiations between the U.S., the U.S.S.R. and Britian from 1977 to 1980. Those negotiations have not resumed since 1980. Inadequate seismic means of verifying a CTBT, Soviet cheating on the 150-kt limit of the Treshold Test Ban Treaty of 1976, and the need to develop and test new nuclear weapons were cited in 1982 by the U.S. government as reasons for not continuing negotiations for a CTBT. The first two reservations, which depend heavily on seismological information, are not supported scientifically. A CTBT could help to put a lid on the seemingly endless testing of new generations of nuclear weapons by both superpowers.

Sykes, Lynn R.; Evernden, Jack F.; Cifuentes, Inés

1983-10-01

240

Criteria of micellar dissolution  

SciTech Connect

Conditions of micellar dissolution to soluble surfactants are discussed. Simple and pictorial conditions for micellar dissolution are as follows: (1) the surfactant in the presence of a solvent has to be in the liquid state so that the solvent dissolves in the surfactant phase; (2) the solubility of solvent in the surfactant phase has to be infinite so that the surfactant disperses forming micelles, otherwise a 2-phase solution is obtained; (3) the saturation concentration of surfactant in the solvent has to be small so that the micelles are thermodynamically stable above the saturation concentration of molecular dispersion. These criteria are equally valid for water-soluble polymers such as proteins. 16 references.

Shinoda, K.

1981-10-29

241

Novel quantitative test method of laser range finder for range measurement: computerized instrument test method  

NASA Astrophysics Data System (ADS)

The maximum rang finding ability of laser range finder (LRF) is greatly influenced by various factors under field conditions, and these factors are changing constantly. In this paper, the advantages and shortcomings of traditional test method 'dissipated light power ratio method' through field object target are analyzed. A computerized instrument is developed, this instrument has no influence with field environment and characteristics of targets, it is simple, effective, accurate and quantitative to test comprehensive ability of range measurement which LRF system itself has. This paper introduces optimal formulas by use of computerized instrument to estimate the measuring rang of LRF, studied the theory of equations of measuring range by laser, and made a breakthrough of test method at program control of time-delay simulating space range and transmission and receiving of LRF under field conditions. This computerized test instrument has highly practical application and theoretical guiding meaning in demarcating checking and accepting of product produced by factories.

Chen, Zhibin

1996-10-01

242

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

243

An evaluation of fit factors and dissolution efficiency for the comparison of in vitro dissolution profiles.  

PubMed

Dissolution efficiency (D.E.), the area under a dissolution curve between defined time points, and the fit factors (f1 and f2) have been compared for the characterisation of dissolution profiles, using data from three batches of a product in nine different packs stored under two conditions. The factors f1 and f2 offer ease of calculation and a simple measure of similarity between pairs of dissolution profiles. This is well suited to the qualitative determination of 'similarity' as required by the FDA's SUPAC Guide. However, they do not provide information on individual batches, including their consistency. In contrast, D.E. does provide such information is well-suited to making quantitative comparisons amongst batches. Because D.E. has a simple physical meaning, it is easier to interpret D.E. data then corresponding f1 and f2 results. The confidence limits in D.E. values provide a useful measure of the variability in batch dissolution and allow the statistical significance of difference in D.E. between pairs of batches to be determined. Both of the above measures lead to the same conclusions regarding the similarity in protective power amongst the nine packs under test and to the value of added desiccant in maintaining the dissolution profile of the product when stored under high humidity conditions. It is concluded that D.E. offers a suitable alternative to the single point dissolution measurement for QC of immediate release products. PMID:9682166

Anderson, N H; Bauer, M; Boussac, N; Khan-Malek, R; Munden, P; Sardaro, M

1998-08-01

244

Acceleration of in vitro dissolution studies of sustained release dosage form of theophylline and in vitro-in vivo evaluations in terms of correlations.  

PubMed

The aim of the study was to accelerate the dissolution of the sustained release dosage forms using both elevated temperature and high rpm rates. Teokap(®) SR 200 mg pellets were tested by in vitro sustained and accelerated dissolution studies using USP XXIII rotating paddle method. Sustained dissolution studies were carried out for 12 h in phosphate buffer at 37 ± 0.5°C and 50 rpm. Accelerated dissolution studies were performed for 48 min in distilled water at 90 ± 1°C and 250 rpm. The results obtained from accelerated and sustained dissolution studies were correlated using both linear and linear kinetic correlation methods by a computer program. While r (2) and maximum error between calculated and observed drug release rates were found to be 0.9129 and 15.9%, respectively, in linear correlation method, these values were observed as 0.9938 and 3.6%, respectively, in linear kinetic correlation method. In vivo plasma concentration data were obtained from six New Zealand rabbits after administration of a single dose of Teokap(®) SR 200 mg pellet. Then, the results of in vivo study were evaluated with in vitro accelerated and sustained dissolution results by applying them to in vitro-in vivo linear correlations. As a result of these correlations, it was shown that the in vitro correlation plots were very similar to the plot which was obtained by the in vivo study (f (2) = 73.81-77.11). This study suggested a way to prevent the loss of time for routine dissolution studies of sustained release preparations for quality control procedures using in vitro accelerated dissolution tests. The storage and quarantine periods of the product in process and process controls in the manufactories could be shortened by this method. Calculation of the in vivo performance of sustained release dosage forms using the results of the accelerated dissolution studies may be counted as another advantage of the method. PMID:21739190

Ertan, Gökhan; Karasulu, Ercüment; Ozgüney, I??k; Karasulu, Ye?im; Apayd?n, Sebnem; Kantarc?, Gülten; Yurdasiper, Aysu; Ege, Mehmet Ali

2011-12-01

245

Fatigue testing a plurality of test specimens and method  

NASA Technical Reports Server (NTRS)

Described is a fatigue testing apparatus for simultaneously subjecting a plurality of material test specimens to cyclical tension loading to determine the fatigue strength of the material. The fatigue testing apparatus includes a pulling head having cylinders defined therein which carry reciprocating pistons. The reciprocation of the pistons is determined by cyclical supplies of pressurized fluid to the cylinders. Piston rods extend from the pistons through the pulling head and are attachable to one end of the test specimens, the other end of the test specimens being attachable to a fixed base, causing test specimens attached between the piston rods and the base to be subjected to cyclical tension loading. Because all the cylinders share a common pressurized fluid supply, the breaking of a test specimen does not substantially affect the pressure of the fluid supplied to the other cylinders nor the tension applied to the other test specimens.

Hodo, James D. (inventor); Moore, Dennis R. (inventor); Morris, Thomas F. (inventor); Tiller, Newton G. (inventor)

1987-01-01

246

Mergers, Annexations, Dissolutions  

ERIC Educational Resources Information Center

Consolidations come in all shapes and sizes, including mergers, annexations and dissolutions. They do not all take place under state mandate, however. A handful of districts consolidate every year in some states like Illinois that have large numbers of small districts, many of them dual districts that serve K-8 or 9-12 in the same geographic area.…

Russo, Alexander

2006-01-01

247

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

248

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

249

Multiphase dissolution flows  

Microsoft Academic Search

Analytical models have been developed to calculate steady and unsteady one-dimensional nonhomogeneous multiphase dissolution flows in variable area inclined channels. The models are based on conservation of mass and momentum of each of the phases for a liquid containing dissolved gas which tends to come out of solution in a supersaturated pressure field. The steady-state system of nonlinear initial value

1981-01-01

250

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

251

Fracture mechanics life analytical methods verification testing  

NASA Technical Reports Server (NTRS)

The objective was to evaluate NASCRAC (trademark) version 2.0, a second generation fracture analysis code, for verification and validity. NASCRAC was evaluated using a combination of comparisons to the literature, closed-form solutions, numerical analyses, and tests. Several limitations and minor errors were detected. Additionally, a number of major flaws were discovered. These major flaws were generally due to application of a specific method or theory, not due to programming logic. Results are presented for the following program capabilities: K versus a, J versus a, crack opening area, life calculation due to fatigue crack growth, tolerable crack size, proof test logic, tearing instability, creep crack growth, crack transitioning, crack retardation due to overloads, and elastic-plastic stress redistribution. It is concluded that the code is an acceptable fracture tool for K solutions of simplified geometries, for a limited number of J and crack opening area solutions, and for fatigue crack propagation with the Paris equation and constant amplitude loads when the Paris equation is applicable.

Favenesi, J. A.; Clemons, T. G.; Riddell, W. T.; Ingraffea, A. R.; Wawrzynek, P. A.

1994-01-01

252

40 CFR 63.344 - Performance test requirements and test methods.  

Code of Federal Regulations, 2013 CFR

...Method 306 or 306A testing and calculate an outlet mass emission rate. (iv...three-run average mass emission rate determined from testing using Method 306...three-run average mass emission rate determined from testing using Method...

2013-07-01

253

Method and Apparatus for Testing Electromagnetic Connectivity Drill String.  

National Technical Information Service (NTIS)

A method and apparatus for testing electromagnetic connectivity in a drill string are disclosed. The method includes transmitting a test signal down a transmission path in a drill string; receiving a reflection of the test signal; and determining from the...

D. B. Bartholomew D. R. Hall D. S. Pixton M. Pawle M. A. Soares

2004-01-01

254

Using noble gas tracers to estimate residual CO2 saturation in the field: results from the CO2CRC Otway residual saturation and dissolution test  

NASA Astrophysics Data System (ADS)

Residual CO2 saturation is a critically important parameter in CO2 storage as it can have a large impact on the available secure storage volume and post-injection CO2 migration. A suite of single-well tests to measure residual trapping was conducted at the Otway test site in Victoria, Australia during 2011. One or more of these tests could be conducted at a prospective CO2 storage site before large-scale injection. The test involved injection of 150 tonnes of pure carbon dioxide followed by 454 tonnes of CO2-saturated formation water to drive the carbon dioxide to residual saturation. This work presents a brief overview of the full test sequence, followed by the analysis and interpretation of the tests using noble gas tracers. Prior to CO2 injection krypton (Kr) and xenon (Xe) tracers were injected and back-produced to characterise the aquifer under single-phase conditions. After CO2 had been driven to residual the two tracers were injected and produced again. The noble gases act as non-partitioning aqueous-phase tracers in the undisturbed aquifer and as partitioning tracers in the presence of residual CO2. To estimate residual saturation from the tracer test data a one-dimensional radial model of the near-well region is used. In the model there are only two independent parameters: the apparent dispersivity of each tracer and the residual CO2 saturation. Independent analysis of the Kr and Xe tracer production curves gives the same estimate of residual saturation to within the accuracy of the method. Furthermore the residual from the noble gas tracer tests is consistent with other measurements in the sequence of tests.

LaForce, T.; Ennis-King, J.; Paterson, L.

2013-12-01

255

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

256

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

257

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...

258

Evaluating Testing Methods by Delivered Reliability  

Microsoft Academic Search

There are two main goals in testing software: (1) To achieve adequate quality (debug testing);the objective is to probe the software for defects so that these can be removed. (2) To assessexisting quality (operational testing); the objective is to gain confidence that the softwareis reliable. The names are arbitrary, and most testing techniques address both goals tosome degree. However, debug

Phyllis G. Frankl; Richard G. Hamlet; Bev Littlewood; Lorenzo Strigini

1998-01-01

259

Pattern formation during fracture dissolution  

Microsoft Academic Search

A number of experimental and numerical studies of dissolution in fractured and porous rocks have established that the evolving topography of the pore space depends strongly on the fluid flow and mineral dissolution rates. Remarkably, there exists a wide parameter range in which positive feedback between fluid transport and mineral dissolution leads to the spontaneous formation of pronounced channels, frequently

P. Szymczak; T. Ladd

2009-01-01

260

[Olfactory testing: diagnostic methods for investigating the sense of smell].  

PubMed

For the testing of a person's sense of smell, both subjective and objective methods are available. Subjective tests include odor identification, threshold and discrimination tests. A prerequisite for successful testing is the ability and willingness of the patient to cooperate. For testing smell in the demented, comatose or simulating patient, the measurement of chemosensory evoked potentials (CSEP) is an established method. PMID:16937875

Pfaar, O; Klimek, L

2006-08-01

261

Spousal Dissimilarity, Race, and Marital Dissolution  

ERIC Educational Resources Information Center

I test the claims that spousal differences in ideational, behavioral, and other traits contribute to elevated rates of marital dissolution among African Americans. Using data from 3 waves of the National Survey of Families and Households (N = 5,424), I find that African American spouses experience high levels of dissimilarity in traits that may…

Clarkwest, Andrew

2007-01-01

262

K Basin sludge dissolution engineering study  

Microsoft Academic Search

The purpose of this engineering study is to investigate the available technology related to dissolution of the K Basin sludge in nitric acid. The conclusion of this study along with laboratory and hot cell tests with actual sludge samples will provide the basis for beginning conceptual design of the sludge dissolver. The K Basin sludge contains uranium oxides, fragments of

Westra

1998-01-01

263

49 CFR 383.133 - Testing methods.  

Code of Federal Regulations, 2010 CFR

...possess the knowledge required under § 383.111. (g) Each basic knowledge test...test covering the areas referred to in § 383.111 for the applicable vehicle group, shall...basic knowledge test as described in § 383.111(g), shall contain a number of...

2010-10-01

264

49 CFR 383.133 - Testing methods.  

Code of Federal Regulations, 2010 CFR

...possess the knowledge required under § 383.111. (g) Each basic knowledge test...test covering the areas referred to in § 383.111 for the applicable vehicle group, shall...basic knowledge test as described in § 383.111(g), shall contain a number of...

2009-10-01

265

Sodium sulfate - Deposition and dissolution of silica  

NASA Technical Reports Server (NTRS)

The hot-corrosion process for SiO2-protected materials involves deposition of Na2SO4 and dissolution of the protective SiO2 scale. Dew points for Na2SO4 deposition are calculated as a function of pressure, sodium content, and sulfur content. Expected dissolution regimes for SiO2 are calculated as a function of Na2SO4 basicity. Controlled-condition burner-rig tests on quartz verify some of these predicted dissolution regimes. The basicity of Na2SO4 is not always a simple function of P(SO3). Electrochemical measurements of an (Na2O) show that carbon creates basic conditions in Na2SO4, which explains the extensive corrosion of SiO2-protected materials containing carbon, such as SiC.

Jacobson, Nathan S.

1989-01-01

266

A Method for Severely Constrained Item Selection in Adaptive Testing  

Microsoft Academic Search

Previous attempts at incorporating expert test construction practices into computerized adaptive testing paradigms are described. A new method is presented for incorporating a large number of con straints on adaptive item selection. The meth odology emulates the test construction practices of expert test specialists, which is a necessity if com puterized adaptive testing is to compete with con ventional tests.

Martha L. Stocking; Len Swanson

1993-01-01

267

Diagnostic methods for CW laser damage testing  

NASA Astrophysics Data System (ADS)

High performance optical coatings are an enabling technology for many applications - navigation systems, telecom, fusion, advanced measurement systems of many types as well as directed energy weapons. The results of recent testing of superior optical coatings conducted at high flux levels will be presented. The diagnostics used in this type of nondestructive testing and the analysis of the data demonstrates the evolution of test methodology. Comparison of performance data under load to the predictions of thermal and optical models shows excellent agreement. These tests serve to anchor the models and validate the performance of the materials and coatings.

Stewart, Alan F.; Shah, Rashmi S.

2004-06-01

268

Hesperidin gastroresistant microparticles by spray-drying: preparation, characterization, and dissolution profiles.  

PubMed

Gastroresistant microparticles for oral administration of hesperidin (Hd) were produced by spray-drying using cellulose acetate phthalate (CAP) as enteric polymer in different polymer/Hd weight ratio (1:1, 3:1, and 5:1), and a series of enhancers of the dissolution rate, such as sodium carboxymethylcellulose crosslinked (CMC), sodium dodecylbenzene sulfonate (SDBS), or Tween85. The raw materials and the microparticles were investigated by differential-scanning calorimetry, X-ray diffraction, infrared spectroscopy and imaged using scanning electron and fluorescence microscopy. In vitro dissolution tests were conducted using a pH-change method to investigate the influence of formulative parameters on the dissolution/release properties of the drug. CAP/Hd microparticles showed a good gastro-resistance but incomplete drug dissolution in the simulated intestinal fluid (SIF). The presence of the enhancers in the formulation produced well-formed microparticles with different size and morphology, containing the drug well coated by the polymer. All the enhancers were able to increase the dissolution rate of Hd in the simulated intestinal environment without altering CAP ability to protect Hd in the acidic fluid. The spray-drying technique and process conditions selected were effective in microencapsulating and stabilizing the flavonoid giving satisfactory encapsulation efficiency, product yield, and microparticles morphology, and a complete drug release in the intestine. PMID:19381835

Sansone, Francesca; Rossi, Alessandra; Del Gaudio, Pasquale; De Simone, Francesco; Aquino, Rita Patrizia; Lauro, Maria Rosaria

2009-01-01

269

40 CFR 63.1656 - Performance testing, test methods, and compliance demonstrations.  

Code of Federal Regulations, 2010 CFR

...runs comprising the performance test does not exceed...conducting multiple performance tests to establish...recorded during performance tests using the same test methods specified in this...control system fan motor amperes and...

2010-07-01

270

40 CFR 63.1656 - Performance testing, test methods, and compliance demonstrations.  

Code of Federal Regulations, 2010 CFR

...runs comprising the performance test does not exceed...conducting multiple performance tests to establish...recorded during performance tests using the same test methods specified in this...control system fan motor amperes and...

2009-07-01

271

Applications of microwave oven sample dissolution in analysis  

SciTech Connect

Heating in a microwave oven in the presence of acid mixtures dissolves the metals from powdered coal, fly ash, oil shales, rocks, sediments, and biological materials. The dissolution is complete within 3 min. Nearly 25 elements (Al, As, Ba, Be, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Si, Sr, Tl, V, and Zn) from the dissolved samples are determined by inductively coupled plasma emission spectrometry. The method has been tested on a variety of standard reference materials, with reproducible and accurate results.

Nadkarni, R.A.

1984-10-01

272

Handbook of Test Methods for Evaluating Chemical Deicers.  

National Technical Information Service (NTIS)

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)...

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

1992-01-01

273

Method of and Apparatus for Non-Destructively Testing Concrete.  

National Technical Information Service (NTIS)

The patent application relates generally to methods of, and apparatus for, testing concrete, and more particularly, to a method of and apparatus for non-destructively testing concrete by impacting the concrete and monitoring induced vibrational energy usi...

M. Gutierrez P. F. Enger

1978-01-01

274

Multiple level C in vitro/in vivo correlation of dissolution profiles of two L-thyroxine tablets with pharmacokinetics data obtained from patients treated for hypothyroidism.  

PubMed

In a previous study aimed to compare the bioavailability of two levothyroxine tablets, we found a good relation between their pharmacokinetics parameters and dissolution profiles, employing the USP dissolution conditions in use at that time (24th edition). Despite the formulations were considered bioequivalent, the test product presented values of AUC and concentrations at steady-state significantly lower (about 10%) than the reference ones. The purpose of the present study was to evaluate if the actual pharmacopeial conditions (with alterations introduced in the first supplement of USP 24) would also allow a good correlation between bioavailability and dissolution data. The partial AUCs were correlated with cumulative levothyroxine amount dissolved at three different times, for each dissolution condition. Employing the old method, test tablets had a slower dissolution rate than the reference ones, resulting in a quite good multiple level C in vitro/in vivo (IVIV) correlation. On the other hand, the very fast dissolution profiles obtained in the actual condition lead to a worse IVIV correlation. Present work indicates that the mild conditions proposed in the older US Pharmacopeia were better than the actual in order to discriminate dissolution profiles of levothyroxine tablets which present subtle, but significant, differences in their pattern of absorption. PMID:15066666

Volpato, Nadia Maria; Silva, Regina Lengruber; Brito, Ana Paula P; Gonçalves, José Carlos S; Vaisman, Mário; Noël, François

2004-04-01

275

On sine dwell or broadband methods for modal testing  

NASA Technical Reports Server (NTRS)

For large, complex spacecraft structural systems, the objectives of the modal test are outlined. Based on these objectives, the comparison criteria for the modal test methods, namely, the broadband excitation and the sine dwell methods are established. Using the Galileo spacecraft modal test and the Centaur G Prime upper stage vehicle modal test as examples, the relative advantages or disadvantages of each method are examined. The usefulness or shortcoming of the methods are given from a practicing engineer's view point.

Chen, Jay-Chung; Wada, Ben K.

1987-01-01

276

Comparison of sine dwell and broadband methods for modal testing  

NASA Technical Reports Server (NTRS)

The objectives of modal tests for large complex spacecraft structural systems are outlined. The comparison criteria for the modal test methods, namely, the broadband excitation and the sine dwell methods, are established. Using the Galileo spacecraft modal test and the Centaur G Prime upper stage vehicle modal test as examples, the relative advantage or disadvantage of each method is examined. The usefulness or shortcomings of the methods are given from a practical engineering viewpoint.

Chen, Jay-Chung

1989-01-01

277

A review of multishaker excitation modal testing methods  

NASA Astrophysics Data System (ADS)

Common modal tests employ either impact excitation with a modally tuned hammer or random excitation with a single shaker. While these methods of testing are usually adequate for simple structures, analysis of complex and in many cases nonlinear structures requires more sophisticated test methods. This paper provides a comprehensive overview of test methods less commonly used, but essential for characterizing the dynamic behavior of complex systems and structures made of composite materials. Among the methods discussed are stepped sine, MIMO, MIMO stepped sine, and normal-mode analysis. The paper discusses the suitability of each test method for various circumstances and offers guidance on the application of each method.

Menon, Arun; Zhao, Weijie

2005-09-01

278

DISSOLUTION OF URANIUM METAL AND ITS ALLOYS  

Microsoft Academic Search

The most useful methods for the dissolution of uranium metal and its ; alloys are reviewed, with particular emphasis on the preparation of solutions for ; analysis. The behavior of the metal and its alloys in the common acids, ethyl ; acetate solutions of bromine and hydrogen chloride, and sodium hydroxide- ; peroxide mixtures is described. Recommendations for dissolving each

R. P. Larsen

1959-01-01

279

Test methods for polymeric insulating materials for outdoor HV insulation  

Microsoft Academic Search

The paper describes an analysis of standardized and non-standardized test methods for polymeric insulating materials, either suitable or applied for, outdoor HV insulation. The analysis particularly considers the increasing use of silicone elastomers for composite insulators. In the first part, test methods covering erosion\\/tracking performance and hydrolysis phenomena are discussed. These are inclined plane test (IPT) and arc test (AT)

R. Barsch; H. Jahn; J. Lambrecht; F. Schmuck

1999-01-01

280

Subscale Test Methods for Combustion Devices  

NASA Technical Reports Server (NTRS)

Stated goals for long-life LRE s have been between 100 and 500 cycles: 1) Inherent technical difficulty of accurately defining the transient and steady state thermochemical environments and structural response (strain); 2) Limited statistical basis on failure mechanisms and effects of design and operational variability; and 3) Very high test costs and budget-driven need to protect test hardware (aversion to test-to-failure). Ambitious goals will require development of new databases: a) Advanced materials, e.g., tailored composites with virtually unlimited property variations; b) Innovative functional designs to exploit full capabilities of advanced materials; and c) Different cycles/operations. Subscale testing is one way to address technical and budget challenges: 1) Prototype subscale combustors exposed to controlled simulated conditions; 2) Complementary to conventional laboratory specimen database development; 3) Instrumented with sensors to measure thermostructural response; and 4) Coupled with analysis

Anderson, W. E.; Sisco, J. C.; Long, M. R.; Sung, I.-K.

2005-01-01

281

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

282

A Testing Method for Java ME Software  

Microsoft Academic Search

Java ME (Java micro edition) technology is being widely used in the mobile computing field. Testing of Java ME software is an important and challenging task. This paper reviews the most popular Java ME testing frameworks, i.e. JMUnit, J2MEUnit and Mobile JUnit, and addresses their defects. And then the JT Harness\\/ME Framework is discussed and studied, which is somewhat currently

Zhenglei Wang; Zhenjun Du; Rong Chen

2009-01-01

283

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

284

In vitro dissolution and in vivo bioequivalence evaluation of two brands of isosorbide 5-mononitrate sustained release tablets.  

PubMed

The purpose of the present study was to test a sustained release-tablet newly formulated with synthetic paraffin and compare its bioequivalence to that of the Imdur® Long-Acting tablet, based on the guidelines of the Korean Food and Drug Administration.Dissolution test was performed in 4 different dissolution media. A LC/MS/MS method of isosorbide 5-mononitrate in human plasma was validated. In vivo bioequivalence tests of the 2 isosorbide 5-mononitrate tablets were performed in both preprandial and postprandial states.A comparative dissolution test gave similar results for both tablets in all dissolution media tested: 40% dissolution in pH 1.2 at 2?h and 80% dissolution in pH 4.0, pH 6.8, or water at 10?h. In a bioequivalence study to compare 2 tablets, the mean total area under the curve (AUCt) and peak concentration (Cmax) in the fasted state were 8?476.0?ng?·?h/mL and 540.4?ng/mL, respectively, for the Imdur® Long Acting Tablet 60?mg, and 8?701.4?ng?·?h/mL and 564.2?ng/mL, respectively, for the test tablet. The mean AUCt and Cmax in the fed state were 8?793.5?ng?·?h/mL and 559.9?ng/mL, respectively, for the Imdur® Long-Acting tablet 60?mg, and 8?639.8?ng?·?h/mL and 617.9?ng/mL, respectively, for the test tablet. The 90% confidence intervals using log transformed data were within the acceptable range of 0.8?-?1.25.Based on these statistical analyses, we conclude that the test tablet is bioequivalent to the Imdur® Long-Acting tablet 60?mg in both the preprandial and postprandial states. PMID:23093481

Kim, Y-H; Choi, K-S; Kam, S-H; Lee, K-H; Park, J-S

2012-12-01

285

Analysis of Formation and Interfacial WC Dissolution Behavior of WC-Co/Invar Laser-TIG Welded Joints  

NASA Astrophysics Data System (ADS)

During the valve fabrication, hard metal is welded to stainless steel or invar alloy for sealing purposes because of its good heat resistance operating at 500 °C. However, WC (tungsten carbide) dissolution in weld pool softens the hard metal and decreases mechanical properties near the hard metal/weld interface. In order to analyze the WC dissolution in welded joint, joining of hard metal and invar alloy was carried out using laser-tungsten inert gas hybrid welding method. Microstructures of the weld region, chemical composition were investigated using optical microscope, scanning electron microscopy, and EDAX, respectively. Mechanical properties such as microhardness and four-point bend strength test were performed. Larger and smaller WC dissolution and WC dissolution through transition layer based on thermo-dynamics were discussed. The results thus indicate that WC dissolution led to cellular microstructure, columnar crystal, and transition layer under the effect of laser beam and tungsten arc. WC dissolution was affected by metal ions Fe+, Ni+, Co+ exchange in W-M-C system, and WC grain growth was driven by forces caused by laser beam and tungsten arc in larger WC, smaller WC, and liquid Fe, Ni systems.

Xu, P. Q.; Ren, J. W.; Zhang, P. L.; Gong, H. Y.; Yang, S. L.

2013-02-01

286

Testing statistical downscaling methods in simulated climates  

Microsoft Academic Search

The consistency of two statistical downscaling methods and two different predictors to estimate past (last millennium) and future (21st century) precipitation in the Iberian and Scandinavian Peninsulas is assessed in the surrogate climate of a coupled climate model simulation. The methods are based on canonical correlation analysis and the search for analogs, with sea level pressure (SLP) and 500 mb

M. D. Frías; E. Zorita; J. Fernández; C. Rodríguez-Puebla

2006-01-01

287

A Survey of Methods for Planning and Analyzing Accelerated Tests  

Microsoft Academic Search

This paper surveys methods for planning and analyzing accelerated life tests. Many of these methods are new and providemore informative results for less time and cost than do previous methods. These methods are of value to all who plan and analyze accelerated tests on any product or material.

Wayne Nelson

1974-01-01

288

European test methods for fuel economy oils  

Microsoft Academic Search

Europe is well aware of work by the ASTM Fuel Efficient Engine Oil Task Force to develop test procedures for the measurement of the effects of the engine oil on the fuel economy of passenger cars and light duty vehicles. These procedures are designed to cover North American requirements and are not entirely suitable for European needs. The paper explains

K. P. Bush; D. C. Roberts; T. Villis

1983-01-01

289

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

290

Testing and Development of Sorbent Research Methods.  

National Technical Information Service (NTIS)

The aim of the present investigation was to create a foundation for standardized sorbent research methods and to contribute to work on water purification with the aid of sorbent products in Finland and in the USSR.

R. Thun D. Asplund V. Korshunov L. Zhemkova

1980-01-01

291

Improved Ground Vibration Test Method. Volume I. Research Report.  

National Technical Information Service (NTIS)

Research was conducted to develop an improved method for ground vibration testing of airplanes. The resulting method, a single point excitation-frequency response analysis method, utilizes the computer, modern electronic equipment, developments in vibrati...

C. S. Doherty D. L. Brown D. W. Gimmestad R. F. Michalak R. J. Allemang

1980-01-01

292

[Determination of dissolution of liuwei dihuang concentrated pills based on multi-index components].  

PubMed

With the content of gallic acid, loganin, paeoniflorin and paeonol as the indexes, to screen out dissolution determination conditions, establish the dissolution determination method for multi-index components in Liuwei Dihuang concentrated pills, calculate and map the accumulative dissolution curve, and then compare the dissolution of products from different pharmaceutical factories through the similarity factor (f2). According to the results, the optimum dissolution determination conditions were the paddle method, with 250 mL 0.1 mol x L(-1) hydrochloric acid as the dissolution medium, and a rotation rate of 100 r x min(-1). The similarity factor values (f2) of the dissolution curves of the four main components of Liuwei Dihuang concentrated pills from different pharmaceutical factories were mostly less than 50. This demonstrated a significant difference in the dissolution of Liuwei Dihuang concentrated pills from different pharmaceutical factories, and provided scientific basis for improving the equality evaluation of Liuwei Dihuang concentrated pills. PMID:24761638

Luo, Yun; Hao, Wei-Wei; Zhang, Jing; Liang, Xin-Li; Zhao, Guo-Wei; Yang, Ming; Liao, Zheng-Gen

2014-01-01

293

Low-cycle fatigue testing methods  

NASA Technical Reports Server (NTRS)

The good design of highly stressed mechanical components requires accurate knowledge of the service behavior of materials. The main methods for solving the problems of designers are: determination of the mechanical properties of the material after cyclic stabilization; plotting of resistance to plastic deformation curves; effect of temperature on the life on low cycle fatigue; and simulation of notched parts behavior.

Lieurade, H. P.

1978-01-01

294

78 FR 68076 - Request for Information on Alternative Skin Sensitization Test Methods and Testing Strategies and...  

Federal Register 2010, 2011, 2012, 2013

...to replace the use of animals in skin sensitization testing for hazard and potency...Laboratory for Alternatives to Animal Testing (EURL ECVAM), and by...Alternative (non- animal) methods for cosmetics testing: current status and...

2013-11-13

295

40 CFR 63.344 - Performance test requirements and test methods.  

Code of Federal Regulations, 2010 CFR

...results of such testing may be used...of Chromium Emissions From Decorative...blanket type fume suppressants...Method 306 testing and calculate an outlet mass emission rate. ...average mass emission rate determined from testing using...

2009-07-01

296

40 CFR 63.344 - Performance test requirements and test methods.  

Code of Federal Regulations, 2010 CFR

...results of such testing may be used...of Chromium Emissions From Decorative...blanket type fume suppressants...Method 306 testing and calculate an outlet mass emission rate. ...average mass emission rate determined from testing using...

2010-07-01

297

Environment-sensitive fracture: Evaluation and comparison of test methods  

Microsoft Academic Search

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

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

1984-01-01

298

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

299

Efavirenz Dissolution Enhancement I: Co-Micronization  

PubMed Central

AIDS constitutes one of the most serious infectious diseases, representing a major public health priority. Efavirenz (EFV), one of the most widely used drugs for this pathology, belongs to the Class II of the Biopharmaceutics Classification System for drugs with very poor water solubility. To improve EFV’s dissolution profile, changes can be made to the physical properties of the drug that do not lead to any accompanying molecular modifications. Therefore, the study objective was to develop and characterize systems with efavirenz able to improve its dissolution, which were co-processed with sodium lauryl sulfate (SLS) and polyvinylpyrrolidone (PVP). The technique used was co-micronization. Three different drug:excipient ratios were tested for each of the two carriers. The drug dispersion dissolution results showed significant improvement for all the co-processed samples in comparison to non-processed material and corresponding physical mixtures. The dissolution profiles obtained for dispersion with co-micronized SLS samples proved superior to those of co-micronized PVP, with the proportion (1:0.25) proving the optimal mixture. The improvements may be explained by the hypothesis that formation of a hydrophilic layer on the surface of the micronized drug increases the wettability of the system formed, corroborated by characterization results indicating no loss of crystallinity and an absence of interaction at the molecular level.

da Costa, Maira Assis; Seiceira, Rafael Cardoso; Rodrigues, Carlos Rangel; Hoffmeister, Cristiane Rodrigues Drago; Cabral, Lucio Mendes; Rocha, Helvecio Vinicius Antunes

2012-01-01

300

Dissolution inhibitors for 157-nm photolithography  

NASA Astrophysics Data System (ADS)

The focus of 157 nm lithographic research is shifting from materials research to process development. Poly (2-(3,3,3-trifluoro-2-trifuoromethyl-2-hydroxypropyl) bicyclo[2.2.1]heptane-5-ene) (PNBHFA) has received a great deal of attention as a possible base resin for 157 nm lithography. The Asahi Glass RS001 polymer, which was introduced at SPIE in 2002, has also shown promise as a 157 nm base resin due to its low absorbance. Partial protection of either polymer with an acid labile protecting group is a common design for functional photoresists. We previously reported the blending of the carbon monoxide copolymers with PNBHFA copolymers to achieve the critical number of protected sites for optimum imaging performance and contrast. Our group has since studied the use of the unprotected base resin with an additive monomeric dissolution inhibitors (DIs) and a photoacid generator (PAG) to form a three component resist. Surprisingly unprotected PNBHFA was discovered to have dissolution inhibition properties that are far superior to the dissolution inhibition properties of novolac. Several DIs were prepared and tested in PNBHFA to take advantage of the resins dissolution inhibition properties. We have also recently explored the performance of a two-component resist using PAGs that also function as DIs.

Chambers, Charles R.; Kusumoto, Shiro; Lee, Guen Su; Vasudev, Alok; Walthal, Leonidas; Osborn, Brian P.; Zimmerman, Paul; Conley, Will; Willson, C. Grant

2003-06-01

301

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

302

Experimental investigation on test methods for mode II interlaminar fracture testing of carbon fiber reinforced composites  

Microsoft Academic Search

In this paper, experimental investigation on the test methods for mode II interlaminar fracture testing of carbon fiber reinforced composites are carried out. Mode II interlaminar fracture testing of unidirectional composite of carbon fiber reinforced epoxy (T800\\/#3631) are conducted using four kinds of test methods, namely end notched flexure (ENF) test, end loaded split (ELS) test, four-point bend end notched

Wen-Xue Wang; Miko Nakata; Yoshihiro Takao; Terutake Matsubara

2009-01-01

303

Testing a variational method for fluctuations  

NASA Astrophysics Data System (ADS)

A variational approach for many-body systems due to Balian and Vénéroni, which goes beyond the Harrtree-Fock mean field, has been implemented in the case of nuclear Skyrme effective interactions used in examining large amplitude collective motion. An evaluation of the numerical issues involved with the method is presented, in which it is found that the effect of model parameters is generally under control, but long-time running leads to unphysical results.

Stevenson, P. D.; Broomfield, J. M. A.

2010-01-01

304

Comparison of atomic absorption, mass and X-ray spectrometry techniques using dissolution-based and solid sampling methods for the determination of silver in polymeric samples  

NASA Astrophysics Data System (ADS)

In this work, the capabilities and limitations of solid sampling techniques - laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), wavelength dispersive X-ray fluorescence spectrometry (WD-XRFS) and solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS) - for the determination of silver in polymers have been evaluated and compared to those of acid digestion and subsequent Ag determination using pneumatic nebulization ICPMS (PN-ICPMS) or flame AAS (FAAS). In a first stage, two dissolution procedures were examined: conventional acid digestion in a Kjeldahl flask and the combination of dry ashing and microwave-assisted digestion. Accurate results for Ag could be obtained, although occasionally, problems of analyte losses and/or incomplete dissolution were observed. LA-ICPMS shows potential for direct analysis of solid materials, but calibration was found to be difficult. A polypropylene sample was used as standard. This approach provided satisfactory results for other polypropylene samples and even for other types of plastics, provided that the 13C + signal was used as internal reference, correcting for variations in ablation efficiency. However, the results for polyoxymethylene were overestimated. Similar calibration problems appeared with WD-XRFS, due to differences in absorption efficiency of X-rays. In this case, the accuracy could be improved by using a matrix correction procedure, which however required the matrix composition to be known into sufficient detail. SS-ETAAS, proved to be a fast approach that allowed accurate determination of Ag in polymers using aqueous standard solutions for calibration. Due to the high Ag content and the excellent sensitivity, the use of a 3-field mode Zeeman-effect background correction system was essential for the extension of the working range.

De Schrijver, Isabel; Aramendia, Maite; Vincze, Laszlo; Resano, Martín; Dumoulin, Ann; Vanhaecke, Frank

2007-11-01

305

Development of an oxygen impact-testing method  

NASA Technical Reports Server (NTRS)

The development of a gaseous oxygen impact test method to aid in the selection of materials for high pressure oxygen systems is discussed. The objectives of the tests and the test equipment used are described. It is concluded that the impact test procedures are adequate for present purposes, but cannot be depended upon for establishing future standards.

Jamison, H. H.

1971-01-01

306

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

307

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

308

Plutonium dissolution process  

DOEpatents

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

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

1994-01-01

309

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

310

Simple Methods for Testing the Molecular Evolutionary Clock Hypothesis  

Microsoft Academic Search

Simple statistical methods for testing the molecular evolutionary clock hypothesis are developed which can be applied to both nucleotide and amino acid sequences. These methods are based on the chi-square test and are applicable even when the pattern of substitution rates is unknown and\\/or the substitution rate varies among different sites. Furthermore, some of the methods can be applied even

Fumio Tajima

1993-01-01

311

Methods of Improving High Frequency Direct Injection Testing.  

National Technical Information Service (NTIS)

Direct injection testing is a valuable tool for identifying electromagnetic effects and critical subsystems prior to expensive, labor intensive free-field testing. However, as the frequencies of interest increase, the method becomes less reliable and the ...

J. Lehr R. Sizemore P. Barre E. Johnson

1997-01-01

312

Efficient Methods for Interoperability Testing Using Event Sequences.  

National Technical Information Service (NTIS)

Many software testing problems involve sequences of events. The methods described in this paper were motivated by testing needs of mission critical systems that may accept multiple communication or sensor inputs and generate output to several communicatio...

D. R. Kuhn J. F. Lawrence J. M. Higdon R. N. Kacker Y. Lei

2012-01-01

313

ASTM test methods for composite characterization and evaluation  

NASA Technical Reports Server (NTRS)

A discussion of the American Society for Testing and Materials is given. Under the topic of composite materials characterization and evaluation, general industry practice and test methods for textile composites are presented.

Masters, John E.

1994-01-01

314

40 CFR 61.125 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standards for Radionuclide Emissions From Elemental Phosphorus Plants § 61.125 Test methods and procedures. (a) Each owner or operator of a source required to test...

2013-07-01

315

A Test of Two Earthquake Modeling Methods  

NASA Astrophysics Data System (ADS)

A primary challenge in earthquake modeling is to decide which fundamental mechanisms are required to accurately reproduce the earthquake process, and which are less important. With this in mind, we compared two modeling methods that incorporate different levels of approximation in the earthquake process. The first model, DYNA3D, solves the full dynamic equations of motion (including the frictional interaction on the fault and wave propagation) by the finite element method, but uses a simple slip-weakening friction law. The second model rapidly simulates large earthquake sequences by applying quasi-static approximations with rate- and state- dependent friction and long-range elastic interactions. We investigated how different aspects of the model (e.g. initial stress, and rupture location) affect different features of the simulated ruptures (e.g. slip and stress drop) and to what extent the models agreed with each other on the resulting properties. We found the quasi-static model can qualitatively reproduce the general slip and stress drop patterns of earthquake rupture given by the fully dynamic model as well as produce different modes of rupture (crack-like and rupture pulses). As expected, rupture velocity and the details of the slip rate function agreed the least.

Burrill, C.; Richards-Dinger, K.; Dieterich, J.; Oglesby, D. D.

2007-12-01

316

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

317

Stability-indicating assay, dissolution, and content uniformity of sodium levothyroxine in tablets.  

PubMed

A reverse-phase high-performance liquid chromatographic (HPLC) method for determining sodium levothyroxine in tablet formulations is described. The sodium levothyroxine was extracted from tablets using a mobile phase consisting of 60% acetonitrile and 40% aqueous buffer. After centrifugation 200 microliter of the solution was chromatographed on a 10-micron C18 column. The method gave accurate results when tested against the USP method, by the standard additions method, and by the spiked-placebo method. The method can also be used to determine content uniformity and dissolution of sodium levothyroxine tablets. PMID:6644603

Richheimer, S L; Amer, T M

1983-11-01

318

Overview of Non-Volatile Testing and Screening Methods  

NASA Technical Reports Server (NTRS)

Testing methods for memories and non-volatile memories have become increasingly sophisticated as they become denser and more complex. High frequency and faster rewrite times as well as smaller feature sizes have led to many testing challenges. This paper outlines several testing issues posed by novel memories and approaches to testing for radiation and reliability effects. We discuss methods for measurements of Total Ionizing Dose (TID).

Irom, Farokh

2001-01-01

319

Applications of laser methods to automative seat modal testing  

NASA Astrophysics Data System (ADS)

Laser methods are being applied to automotive seat vibration testing methods. The ability to perform non-contact tests is very useful when test specimens are handmade prototypes which cannot be damaged. More importantly, the low input force levels required by laser vibrometers results in more linear response from seats during modal tests; low input force levels limit the effect of freeplay in the recliner and tracks. Finally, the absence of mass loading allows exploring the dynamic interaction of the cover and frame.

French, Mark; Knittel, Jud; Wyszynski, Artur

1996-08-01

320

Methods for testing steels and surfacing alloys for wear resistance  

SciTech Connect

Direct methods are argued to be advantageous for determining the wear resistance of various materials. A methodology and experimental facilities are proposed for testing steels and surfacing alloys for wear resistance, a simple versatile method for fabricating surface-hardened test specimens is described, and standard conditions for abrasive wear tests are recommended. Wear-resistance testing results for experimental and commercial steels and surfacing alloys are given.

Sorokin, G.M.; Vaskul, P.N. [I.M. Gubkin State Oil and Gas Academy, Moscow (Russian Federation)

1995-10-01

321

Olivine dissolution in basaltic melt  

NASA Astrophysics Data System (ADS)

The main purpose of this work is to understand and quantify diffusive and convective olivine dissolution in basaltic melt. Crystal dissolution and growth in a magma chamber is often accompanied by the descent or ascent of the crystal in the chamber due to gravity. The motion induces convection that enhances mass transport. Such convective dissolution and growth rates have not been quantified before. MgO diffusivity in the melt ( DMgO), MgO concentration of the interface melt ( C0) and the effective thickness of the compositional boundary layer (?) are necessary parameters to model the convective dissolution. Experiments of non-convective olivine dissolution in a basaltic melt were conducted at 1271-1480 °C and 0.47-1.42 GPa in a piston-cylinder apparatus. At specific temperature and pressure conditions, multiple experiments of different durations show that the interface melt reaches near-saturation within 2 min. Therefore, diffusion, not interface reaction, is the rate-controlling step for non-convective olivine dissolution in basaltic melt. The compositional profile length and olivine dissolution distance are proportional to the square root of experimental duration, consistent with diffusive dissolution. DMgO and C0 are obtained from the experimental results. DMgO displays Arrhenian dependence on temperature, but the pressure dependence is small and not resolved. C0 increases with increasing temperature and decreases with increasing pressure. Comparison with literature data shows that DMgO depends strongly on the initial melt composition, while C0 does not. ? is estimated from fluid dynamics. DMgO/?, which characterizes the kinetic and dynamic aspects of convective crystal dissolution, is parameterized as a function of temperature, pressure, and olivine composition. Convective olivine dissolution rate in basaltic melt can be conveniently calculated from the model results. Application to convective crystal growth and xenolith digestion is discussed.

Chen, Yang; Zhang, Youxue

2008-10-01

322

Standard test method for size of anthracite  

SciTech Connect

This method covering screen analysis of anthracite is used to determine the percentage of undersize or oversize in ny given commercial size. The values stated in inch-pound units are to be regarded as the standard. Procedure, in case th coal is wet, air-dryit before screening. Determine the undersize first. For broken, egg, and stove sizes, up-end each piece by hand on the screen, to determine whether in any position it passes through the screen. For nut, pea, buckwheat, and rice sizes, shake the screens gently with a reciprocating horizontal motion, so as to avoid breakage ofthe coal, until practically no more coal will pass through the openings. Screen the coal in such increments as will allow the pieces to be in direct contact with the screen openings after the completion of the shaking of each increment.

Not Available

1980-01-01

323

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

324

25 CFR 11.606 - Dissolution proceedings.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Dissolution proceedings. 11.606 Section...Domestic Relations § 11.606 Dissolution proceedings. (a) Either...parties to the marriage may initiate dissolution proceedings. (b)...

2011-04-01

325

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

326

Fracture mechanics life analytical methods verification testing  

NASA Technical Reports Server (NTRS)

Verification and validation of the basic information capabilities in NASCRAC has been completed. The basic information includes computation of K versus a, J versus a, and crack opening area versus a. These quantities represent building blocks which NASCRAC uses in its other computations such as fatigue crack life and tearing instability. Several methods were used to verify and validate the basic information capabilities. The simple configurations such as the compact tension specimen and a crack in a finite plate were verified and validated versus handbook solutions for simple loads. For general loads using weight functions, offline integration using standard FORTRAN routines was performed. For more complicated configurations such as corner cracks and semielliptical cracks, NASCRAC solutions were verified and validated versus published results and finite element analyses. A few minor problems were identified in the basic information capabilities of the simple configurations. In the more complicated configurations, significant differences between NASCRAC and reference solutions were observed because NASCRAC calculates its solutions as averaged values across the entire crack front whereas the reference solutions were computed for a single point.

Favenesi, J. A.; Clemmons, T. G.; Lambert, T. J.

1994-01-01

327

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

328

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

329

Test methods and design allowables for fibrous composites. Volume 2  

NASA Technical Reports Server (NTRS)

Topics discussed include extreme/hostile environment testing, establishing design allowables, and property/behavior specific testing. Papers are presented on environmental effects on the high strain rate properties of graphite/epoxy composite, the low-temperature performance of short-fiber reinforced thermoplastics, the abrasive wear behavior of unidirectional and woven graphite fiber/PEEK, test methods for determining design allowables for fiber reinforced composites, and statistical methods for calculating material allowables for MIL-HDBK-17. Attention is also given to a test method to measure the response of composite materials under reversed cyclic loads, a through-the-thickness strength specimen for composites, the use of torsion tubes to measure in-plane shear properties of filament-wound composites, the influlence of test fixture design on the Iosipescu shear test for fiber composite materials, and a method for monitoring in-plane shear modulus in fatigue testing of composites.

Chamis, Christos C. (editor)

1989-01-01

330

40 CFR 60.496 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Beverage Can Surface Coating Industry § 60.496 Test methods and procedures. (a) The reference methods in appendix A to...

2013-07-01

331

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

332

Evaluation of Four Quantitative Laboratory Fume Hood Performance Test Methods.  

National Technical Information Service (NTIS)

Four quantitative laboratory fume hood performance test methods were evaluated, including: EPA uranine dye; ASHRAE Freon; EPA SF sub 6 ; and modified EPA SF sub 6 . Each of these methods were evaluated, based on: variability and reproducibility; practical...

L. M. Woodrow

1987-01-01

333

Evaluation criteria and test methods for electrochromic windows  

SciTech Connect

Report summarizes the test methods used for evaluating electrochromic (EC) windows, and summarizes what is known about degradation of their performance, and recommends methods and procedures for advancing EC windows for buildings applications. 77 refs., 13 figs., 6 tabs.

Czanderna, A.W. (Solar Energy Research Inst., Golden, CO (USA)); Lampert, C.M. (Lawrence Berkeley Lab., CA (USA))

1990-07-01

334

Recommendations for Developing Alternative Test Methods for Developmental Neurotoxicity  

EPA Science Inventory

There is great interest in developing alternative methods for developmental neurotoxicity testing (DNT) that are cost-efficient, use fewer animals and are based on current scientific knowledge of the developing nervous system. Alternative methods will require demonstration of the...

335

Dissolution of solid antimony in molten bismuth under static conditions  

Microsoft Academic Search

The dissolution of solid antimony in molten bismuth was studied under static and isothermal conditions using the reaction\\u000a couple and immersion methods between 623 and 773 K. The dissolution of antimony under the antimony upper position, using reaction\\u000a couple method, was governed by diffusion, and the diffusion coefficient of antimony in molten bismuth was obtained as follows:D\\u000a L = 2.08

Yoshifusa Shoji; Sosuke Uchida

1981-01-01

336

All-cellulose nanocomposites by surface selective dissolution of bacterial cellulose  

Microsoft Academic Search

All-cellulose nanocomposites using bacterial cellulose (BC) as a single raw material were prepared by a surface selective\\u000a dissolution method. The effect of the immersion time of BC in the solvent (lithium chloride\\/N,N-dimethylacetamide) during preparation on the nanocomposite properties was investigated. The structure, morphology and mechanical\\u000a properties of the nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and tensile testing.

Nattakan Soykeabkaew; Chandeep Sian; Saharman Gea; Takashi Nishino; Ton Peijs

2009-01-01

337

Phase II of a Six sigma Initiative to Study DWPF SME Analytical Turnaround Times: SRNL's Evaluation of Carbonate-Based Dissolution Methods  

SciTech Connect

The Analytical Development Section (ADS) and the Statistical Consulting Section (SCS) of the Savannah River National Laboratory (SRNL) are participating in a Six Sigma initiative to improve the Defense Waste Processing Facility (DWPF) Laboratory. The Six Sigma initiative has focused on reducing the analytical turnaround time of samples from the Slurry Mix Evaporator (SME) by developing streamlined sampling and analytical methods [1]. The objective of Phase I was to evaluate the sub-sampling of a larger sample bottle and the performance of a cesium carbonate (Cs{sub 2}CO{sub 3}) digestion method. Successful implementation of the Cs{sub 2}CO{sub 3} fusion method in the DWPF would have important time savings and convenience benefits because this single digestion would replace the dual digestion scheme now used. A single digestion scheme would result in more efficient operations in both the DWPF shielded cells and the inductively coupled plasma--atomic emission spectroscopy (ICP-AES) laboratory. By taking a small aliquot of SME slurry from a large sample bottle and dissolving the vitrified SME sample with carbonate fusion methods, an analytical turnaround time reduction from 27 hours to 9 hours could be realized in the DWPF. This analytical scheme has the potential for not only dramatically reducing turnaround times, but also streamlining operations to minimize wear and tear on critical shielded cell components that are prone to fail, including the Hydragard{trademark} sampling valves and manipulators. Favorable results from the Phase I tests [2] led to the recommendation for a Phase II effort as outlined in the DWPF Technical Task Request (TTR) [3]. There were three major tasks outlined in the TTR, and SRNL issued a Task Technical and QA Plan [4] with a corresponding set of three major task activities: (1) Compare weight percent (wt%) total solids measurements of large volume samples versus peanut vial samples. (2) Evaluate Cs{sub 2}CO{sub 3} and K{sub 2}CO{sub 3} fusion methods using DWPF simulated glass (part 1) and (to the extent possible) using DWPF radioactive glass (part 2). (3) Recommend specific equipment to implement the new methods and work with SRNL's Equipment Engineering Section (EES) to ensure compatibility of the equipment with the DWPF shielded cells. The focus of this report is major task activity No.2 (parts 1 and 2). The other two major task activities are to be addressed separately. The measurements supporting task activity No.1 are being conducted at the DWPF. EES is currently designing and fabricating the DWPF cell equipment needed for the new method as part of major task activity No.3.

Edwards, Thomas

2005-09-01

338

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

339

Kinetic study of nitric dissolution of uranium oxide. Etude cinetique de la dissolution de l'oxyde d'uranium.  

National Technical Information Service (NTIS)

The kinetic study of uranium oxide dissolution efficiency was determined at the following temperatures: 20, 40, 60 and 80 C. The rate constant and activation energy could not be calculated by logarithmic and integral methods. This shows the complexity of ...

A. Mellah S. Chegrouche D. Challa-Messad D. Mebarki

1992-01-01

340

Standad test method for lead in gasoline: iodine monochloride method  

SciTech Connect

This method determines total lead in gasolines containing lead alkyls at concentrations between 0.12 and 6.0 g Pb/UK gal, 0.1 and 5.0 g Pb/US gal, and 0.026 and 1.3 g Pb/litre. A known volume of the sample is diluted with heavy distillate and shaken with aqueous iodine monochloride reagent. Any tetraalkyl lead compounds present react with the iodine monochloride and are extracted into the aqueous phase as the dialkyl lead compounds. The aqueous extract is separated from the gasoline and evaporated to low bulk to decompose free iodine monochloride. Any organic matter present is removed by oxidation with nitric acid, which also serves to convert the dialkyl lead compounds into inorganic lead compounds. The residue is dissolved in distilled water and buffered to pH 5 using sodium acetate-acetic acid buffer. The lead content of the buffered solution is determined by titration with EDTA using xylenol orange as indicator.

Not Available

1980-01-01

341

Mathematical modeling of drug dissolution.  

PubMed

The dissolution of a drug administered in the solid state is a pre-requisite for efficient subsequent transport within the human body. This is because only dissolved drug molecules/ions/atoms are able to diffuse, e.g. through living tissue. Thus, generally major barriers, including the mucosa of the gastro intestinal tract, can only be crossed after dissolution. Consequently, the process of dissolution is of fundamental importance for the bioavailability and, hence, therapeutic efficacy of various pharmaco-treatments. Poor aqueous solubility and/or very low dissolution rates potentially lead to insufficient availability at the site of action and, hence, failure of the treatment in vivo, despite a potentially ideal chemical structure of the drug to interact with its target site. Different physical phenomena are involved in the process of drug dissolution in an aqueous body fluid, namely the wetting of the particle's surface, breakdown of solid state bonds, solvation, diffusion through the liquid unstirred boundary layer surrounding the particle as well as convection in the surrounding bulk fluid. Appropriate mathematical equations can be used to quantify these mass transport steps, and more or less complex theories can be developed to describe the resulting drug dissolution kinetics. This article gives an overview on the current state of the art of modeling drug dissolution and points out the assumptions the different theories are based on. Various practical examples are given in order to illustrate the benefits of such models. This review is not restricted to mathematical theories considering drugs exhibiting poor aqueous solubility and/or low dissolution rates, but also addresses models quantifying drug release from controlled release dosage forms, in which the process of drug dissolution plays a major role. PMID:23618956

Siepmann, J; Siepmann, F

2013-08-30

342

Electric-vehicle chassis dynamometer test methods at JPL and their correlation to track tests  

SciTech Connect

Early in its electric vehicle (EV) test program, JPL recognized that EV test procedures were too vague and too loosely defined to permit much meaningful data to be obtained from the testing. Therefore, JPL adopted more stringent test procedures and chose the chassis dynamometer rather than the track as its principal test technique. Through the years, test procedures continued to evolve towards a methodology based on chassis dynamometers which would exhibit good correlation with track testing. Based on comparative dynamometer and track test results on the ETV-1 vehicle, the test methods discussed demonstrate a means by which excellent track-to-dynamometer correlation can be obtained.

Marte, J.; Bryant, J.

1983-04-01

343

Electric vehicle chassis dynamometer test methods at JPL and their correlation to track tests  

NASA Technical Reports Server (NTRS)

Early in its electric vehicle (EV) test program, JPL recognized that EV test procedures were too vague and too loosely defined to permit much meaningful data to be obtained from the testing. Therefore, JPL adopted more stringent test procedures and chose the chassis dynamometer rather than the track as its principal test technique. Through the years, test procedures continued to evolve towards a methodology based on chassis dynamometers which would exhibit good correlation with track testing. Based on comparative dynamometer and track test results on the ETV-1 vehicle, the test methods discussed in this report demonstrate a means by which excellent track-to-dynamometer correlation can be obtained.

Marte, J.; Bryant, J.

1983-01-01

344

Test method for spalling of fire exposed concrete  

Microsoft Academic Search

A new material test method is presented for determining whether or not an actual concrete may suffer from explosive spalling at a specified moisture level. The method takes into account the effect of stresses from hindered thermal expansion at the fire-exposed surface. Cylinders are used, which in many countries serve as standard specimens for testing the compressive strength. Consequently, the

K. D. Hertz; L. S. Sørensen

2005-01-01

345

PREDICTIVE TEST METHODS: PERMEATION OF POLYMERIC MEMBRANES BY ORGANIC SOLVENTS  

EPA Science Inventory

As the result of screening elastomeric materials that may be suitable for formulating chemical-protective clothing, a simple test method has been developed that allows the prediction of the permeation of an organic solvent through a polymeric membrane. The test method, based on l...

346

EPA Flow Reference Method Testing and Analysis: Findings Report. Appendices.  

National Technical Information Service (NTIS)

In the summer of 1997, the U.S. Environmental Protection Agency (EPA) conducted a series of week-long field tests at three electric utility sites to evaluate potential improvements to Method 2, EPA's test method for measuring flue gas volumetric flow in s...

1999-01-01

347

Equating Test Scores Using the Linear Method: A Primer.  

ERIC Educational Resources Information Center

This paper describes four commonly used designs in equating test scores. These designs are: (1) single-group; (2) random-group; (3) equivalent-group; and (4) anchor-test. Each design requires that its data be collected according to specific guidelines. Three of the four methods are illustrated through hypothetical examples. All four methods try to…

Tanguma, Jesus

348

Testing Aspheric Surfaces: Simple Method with a Circular Stop  

Microsoft Academic Search

As an extension of the knife-edge test, a noninterferometric method for inspecting circularly symmetric aspheres is proposed in which the test surface is illuminated by a spherical wave. When a small circular stop is placed around the curvature center of the best-fitting sphere, only rays characteristic for the deviation from a perfect sphere remain unobstructed. An image of the tested

Andrianto Handojo; Hans J. Frankena

1998-01-01

349

Nondestructive testing methods for 55-gallon, waste storage drums  

SciTech Connect

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 reference materials that were reviewed, provides a technical description of the methods that were evaluated, describes the laboratory tests that were conducted and their results, identifies the most promising candidate methods along with the rationale for these selections, and includes a work plan for recommended follow-on activities. This report contains a brief overview and technical description for each of the following NDT methods: magnetic testing techniques; eddy current testing; shearography; ultrasonic testing; radiographic computed tomography; thermography; and leak testing with acoustic detection.

Ferris, R.H.; Hildebrand, B.P.; Hockey, R.L.; Riechers, D.M.; Spanner, J.C. [Pacific Northwest Lab., Richland, WA (United States); Duncan, D.R. [Westinghouse Hanford Co., Richland, WA (United States)

1993-06-01

350

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

351

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

352

Test methods and design allowables for fibrous composites. Volume 2  

Microsoft Academic Search

Topics discussed include extreme\\/hostile environment testing, establishing design allowables, and property\\/behavior specific testing. Papers are presented on environmental effects on the high strain rate properties of graphite\\/epoxy composite, the low-temperature performance of short-fiber reinforced thermoplastics, the abrasive wear behavior of unidirectional and woven graphite fiber\\/PEEK, test methods for determining design allowables for fiber reinforced composites, and statistical methods for calculating

Chamis

1989-01-01

353

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

2010-02-15

354

Method and apparatus for leak testing of pipe  

SciTech Connect

A method is described of testing for leaks in oil field pipe at a rig floor by using a single source of pressurized test gas to actuate a testing tool positioned at a pipe test section and to pressurize the pipe test section to test for leaks. The method consists of: (a) pressurizing a test gas comprising a mixture of a detectable quantity of helium tracer gas and a carrier gas in a ration of helium tracer gas to carrier gas greater than 1:9 by volume to a pressure of at least 3000 psi to provide the single source of pressurized test gas; (b) enclosing an area around the outside of the pipe to define a chamber around the pipe test section to confine a test gas therewithin; (c) actuating the test tool by introducing the pressurized test gas having a ratio of helium tracer gas to carrier gas greater than 1:9 by volume and at a pressure of at least 3000 psi from the single source of pressurized test gas into the test tool to seal off an internal section of pipe to form a closed volume pipe test section; (d) introducing the pressurized test gas from the single source of pressurized test gas at substantially the same ratio of helium tracer gas to carrier gas greater than 1:9 by volume and at substantially the same pressure of at least about 3000 psi as sued to actuate the test tool into the pipe test section; and (d) sensing the presence of leaking helium tracer gas in the chamber around the outside of the pipe test section with a sensing means.

Miller, R.F.; Dwyer, A.L.; Miller, D.A.; Miller, D.L.

1986-07-22

355

On the ability of a Darcy-scale model to capture wormhole formation during the dissolution of a porous medium  

NASA Astrophysics Data System (ADS)

Dissolution of a porous medium creates, under certain conditions, some highly conductive channels called wormholes. The mechanism of propagation is an unstable phenomenon depending on the microscopic properties at the pore scale and is controlled by the injection rate. The aim of this work is to test the ability of a Darcy-scale model to describe the different dissolution regimes and to characterize the influence of the flow parameters on the wormhole development. The numerical approach is validated by model experiments reflecting dissolution processes occurring during acid injection in limestone. Flow and transport macroscopic equations are written under the assumption of local mass non-equilibrium. The coupled system of equations is solved numerically in two dimensions using a finite volume method. Results are discussed in terms of wormhole propagation rate and pore volume injected.

Golfier, F.; Zarcone, C.; Bazin, B.; Lenormand, R.; Lasseux, D.; Quintard, M.

2002-04-01

356

A Review of Biaxial Test Methods for Composites  

Microsoft Academic Search

This paper will give an overview of the existing biaxial test methods for composite materials from the early beginning till\\u000a the currently used methods. An evolution in both the biaxial testing capabilities and the applied inspection methods will\\u000a be shown. The use of composite materials in aerospace, aviation and automotive industry has increased rapidly in recent years,\\u000a In general, composite

A. Smits; C. Ramault; A. Makris; D. Van Hemelrijck; A. Clarke; C. Williamson; M. Gower; R. Shaw; R. Mera; E. Lamkanfi; W. Van Paepegem

357

A method for tensile testing of rolled metal specimens  

Microsoft Academic Search

A method for static mechanical tensile testing of small-section shapes using full-scale specimens is described. Mechanical properties of rolled material as determined by this method agree, although slightly overestimated, with those obtained by the standard method. A plausible explanation is that the use of full-scale (semifull-scale) specimens makes allowance for the nonuniformity of metal properties in the shapes tested. The

S. M. Zhuchkov; A. B. Steblov; Yu. M. Venslav

1995-01-01

358

The Iosipescu shear test method as used for testing polymers and composite materials  

NASA Technical Reports Server (NTRS)

This paper describes a shear test method for polymers and composite materials, based on the Iosipescu (1967) shear test which was originally developed for use with homogeneous isotropic metals. Special attention is given to the loading fixture for the test, the standard specimen design and shear stress measurements. The range of the test applications is indicated. The method is in the final stages of being accepted as an ASTM standard.

Adams, Donald F.

1990-01-01

359

On the effects of subsurface parameters on evaporite dissolution (Switzerland)  

NASA Astrophysics Data System (ADS)

Uncontrolled subsurface evaporite dissolution could lead to hazards such as land subsidence. Observed subsidences in a study area of Northwestern Switzerland were mainly due to subsurface dissolution (subrosion) of evaporites such as halite and gypsum. A set of 2D density driven flow simulations were evaluated along 1000 m long and 150 m deep 2D cross sections within the study area that is characterized by tectonic horst and graben structures. The simulations were conducted to study the effect of the different subsurface parameters that could affect the dissolution process. The heterogeneity of normal faults and its impact on the dissolution of evaporites is studied by considering several permeable faults that include non-permeable areas. The mixed finite element method (MFE) is used to solve the flow equation, coupled with the multipoint flux approximation (MPFA) and the discontinuous Galerkin method (DG) to solve the diffusion and the advection parts of the transport equation.

Zidane, Ali; Zechner, Eric; Huggenberger, Peter; Younes, Anis

2014-05-01

360

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

361

Miniaturization of powder dissolution measurement and estimation of particle size.  

PubMed

The objective was to investigate the applicability and limitations of an approach for estimating particle size from powder dissolution measurement using as little as 50 microg of sample in 1 ml of buffer solutions. The powder dissolution profiles of five sparingly-soluble drugs (hydrochlorothiazide, phenazopyridine hydrochloride, 2-naphthoic acid, indomethacin, and dipyridamole) were evaluated with a novel biexponential spherical particle equation and also the Wang-Flanagan spherical particle non-sink equation. The results were compared to particle sizing based on measured specific surface area by the Brunauer-Emmett-Teller (BET) method, and also based on Coulter counting. With the exception of hydrochlorothiazide, the model compounds indicated some agglomeration in the dissolution media. The dry-state specific surface area was larger than expected from either the Coulter method or the powder-dissolution data, especially for phenazopyridine hydrochloride. The particle radii estimated by the powder dissolution method ranged from 10 to 68 microm, with equilibrium solubilities spanning from 5 microg/ml (dipyridamole) to 911 microg/ml (hydrochlorothiazide). Powder dissolution data collected with the miniaturized apparatus can be used to determine particle size, with estimated values agreeing reasonably with those measured by the Coulter counter method. PMID:19937817

Avdeef, Alex; Tsinman, Konstantin; Tsinman, Oksana; Sun, Na; Voloboy, Dmytro

2009-11-01

362

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

363

Flight-Test Evaluation of Flutter-Prediction Methods  

NASA Technical Reports Server (NTRS)

The flight-test community routinely spends considerable time and money to determine a range of flight conditions, called a flight envelope, within which an aircraft is safe to fly. The cost of determining a flight envelope could be greatly reduced if there were a method of safely and accurately predicting the speed associated with the onset of an instability called flutter. Several methods have been developed with the goal of predicting flutter speeds to improve the efficiency of flight testing. These methods include (1) data-based methods, in which one relies entirely on information obtained from the flight tests and (2) model-based approaches, in which one relies on a combination of flight data and theoretical models. The data-driven methods include one based on extrapolation of damping trends, one that involves an envelope function, one that involves the Zimmerman-Weissenburger flutter margin, and one that involves a discrete-time auto-regressive model. An example of a model-based approach is that of the flutterometer. These methods have all been shown to be theoretically valid and have been demonstrated on simple test cases; however, until now, they have not been thoroughly evaluated in flight tests. An experimental apparatus called the Aerostructures Test Wing (ATW) was developed to test these prediction methods.

Lind, RIck; Brenner, Marty

2003-01-01

364

Investigation into physical-chemical variables affecting the manufacture and dissolution of wet-milled clarithromycin nanoparticles.  

PubMed

A critical problem associated with poor water-soluble drugs is their low and variable bioavailability, which is derived from the slow dissolution and erratic absorption. Nano-formulation has been identified as one approach to enhance the rate and extent of drug absorption for compounds that demonstrate limited water solubility. This study aimed to investigate the physico-chemical variables that affect the manufacture, dissolution and consequent bioavailability of wet-milled clarithromycin (CLA) nanoparticles, a macrolide antibiotic. CLA nanoparticles were prepared using wet milling method followed by freeze-drying. Different stabilizer systems, consisting of surfactants and polymers alone or their combinations were studied to determine the optimum conditions for producing nano-sized CLA particles. In vitro characterizations of the CLA nanoparticles were performed using dynamic light scattering, X-ray powder diffraction, differential scanning calorimetry and dissolution efficiency test. Results showed that in general the wet milling process did not modify the crystallinity of the CLA nanoparticles. The poloxamers and polyvinyl alcohol (PVA) stabilizers resulted in nanoparticles with the smallest particle size and best dissolution rates. Furthermore, poloxamers F68 and F127, and PVA stabilizers demonstrated the best performance in increasing dissolution efficacy. PMID:24093825

Shahbazi Niaz, Maliheh; Traini, Daniela; Young, Paul M; Ghadiri, Maliheh; Rohanizadeh, Ramin

2014-12-01

365

Fire test method for graphite fiber reinforced plastics  

NASA Technical Reports Server (NTRS)

A potential problem in the use of graphite fiber reinforced resin matrix composites is the dispersal of graphite fibers during accidental fires. Airborne, electrically conductive fibers originating from the burning composites could enter and cause shorting in electrical equipment located in surrounding areas. A test method for assessing the burning characteristics of graphite fiber reinforced composites and the effectiveness of the composites in retaining the graphite fibers has been developed. The method utilizes a modified Ohio State University Rate of Heat Release apparatus. The equipment and the testing procedure are described. The application of the test method to the assessment of composite materials is illustrated for two resin matrix/graphite composite systems.

Bowles, K. J.

1980-01-01

366

Anodic dissolution of magnesium in river water  

SciTech Connect

With the aim of revealing the reasons for the low efficiency of protectors based on magnesium, which is observed sometimes, a study was made of its corrosion-electrochemical behavior in a solution similar in the composition of its main components to Volga water and ground water of the European part of the USSR (mg/liter): NaHCO/sub 3/ - 300, MgSO/sub 4/ - 50, CaCl/sub 2/ - 50. A study was made of the effect of the magnitude of anodic current density on the rate of hydrogen release, and also on the change in electrode potential during anodic dissolution. Use of the galvanostatic method made it possible to compare the magnesium dissolution kinetics (according to the change in hydrogen release rate) with the corresponding shift in potential with time.

Petrova, L.M.; Krasnoyarskii, V.V.

1987-03-01

367

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

368

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

369

Mechanisms of classical crystal growth theory explain quartz and silicate dissolution behavior  

PubMed Central

The central control of mineral weathering rates on biogeochemical systems has motivated studies of dissolution for more than 50 years. A complete physical picture that explains widely observed variations in dissolution behavior is lacking, and some data show apparent serious inconsistencies that cannot be explained by the largely empirical kinetic “laws.” Here, we show that mineral dissolution can, in fact, be understood through the same mechanistic theory of nucleation developed for mineral growth. In principle, this theory should describe dissolution but has never been tested. By generalizing nucleation rate equations to include dissolution, we arrive at a model that predicts how quartz dissolution processes change with undersaturation from step retreat, to defect-driven and homogeneous etch pit formation. This finding reveals that the “salt effect,” recognized almost 100 years ago, arises from a crossover in dominant nucleation mechanism to greatly increase step density. The theory also explains the dissolution kinetics of major weathering aluminosilicates, kaolinite and K-feldspar. In doing so, it provides a sensible origin of discrepancies reported for the dependence of kaolinite dissolution and growth rates on saturation state by invoking a temperature-activated transition in the nucleation process. Although dissolution by nucleation processes was previously unknown for oxides or silicates, our mechanism-based findings are consistent with recent observations of dissolution (i.e., demineralization) in biological minerals. 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, Patricia M.; Han, Nizhou; De Yoreo, James J.

2005-01-01

370

ISO standards on test methods for water radioactivity monitoring.  

PubMed

Water is vital to humans and each of us needs at least 1.5L of safe water a day to drink. Beginning as long ago as 1958 the World Health Organization (WHO) has published guidelines to help ensure water is safe to drink. Focused from the start on monitoring radionuclides in water, and continually cooperating with WHO, the International Standardization Organization (ISO) has been publishing standards on radioactivity test methods since 1978. As reliable, comparable and 'fit for purpose' results are an essential requirement for any public health decision based on radioactivity measurements, international standards of tested and validated radionuclide test methods are an important tool for production of such measurements. This paper presents the ISO standards already published that could be used as normative references by testing laboratories in charge of radioactivity monitoring of drinking water as well as those currently under drafting and the prospect of standardized fast test methods in response to a nuclear accident. PMID:23647847

Calmet, D; Ameon, R; Bombard, A; Forte, M; Fournier, M; Herranz, M; Jerome, S; Kwakman, P; Llaurado, M; Tokonami, S

2013-11-01

371

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

372

Heated Purge and Trap Method Development and Testing. Project Summary.  

National Technical Information Service (NTIS)

The Resource Conservation and Recovery Act (RCRA), requires predisposal monitoring of about 370 organic species. A heated purge-trap-desorb (HPTD) analytical method for eight polar, water soluble, volatile organic analytes was developed and tested.

S. V. Lucas H. M. Burkholder A. Alford-Stevens

1988-01-01

373

40 CFR 60.275a - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...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) During...

2010-07-01

374

40 CFR 61.304 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...AIR POLLUTANTS National Emission Standard for Benzene Emissions From Benzene Transfer Operations § 61.304 Test methods...hours, during which at least 300,000 liters of benzene are loaded. If the throughput criterion is...

2013-07-01

375

40 CFR 60.754 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Performance for Municipal Solid Waste Landfills § 60.754 Test methods and procedures. (a)(1) The landfill owner or operator shall calculate...i), for part of the life of the landfill and the actual year-to-year...

2013-07-01

376

40 CFR 60.664 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Manufacturing Industry (SOCMI) Distillation Operations § 60.664 Test methods...control device, prior to any post-distillation dilution of the stream with air, and prior to any post-distillation introduction of halogenated...

2013-07-01

377

A Test Method for Evaluation of Metal Powders.  

National Technical Information Service (NTIS)

A speedy and economical test method for determining the potential of metal powders to achieve desired mechanical properties after consolidation is described. It consists of encapsulating metal powders in an evacuated metal tube and reducing the outside di...

N. Birla V. DePierre

1975-01-01

378

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

379

40 CFR 60.106 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...STATIONARY SOURCES Standards of Performance for Petroleum Refineries § 60.106 Test methods and procedures. (a...should be at about atmospheric pressure. If the pressure in the refinery fuel gas lines is relatively high, a flow control...

2013-07-01

380

An Alternative Method Of Specifying Shock Test Criteria  

NASA Technical Reports Server (NTRS)

Shock testing of aerospace vehicle hardware has presented many challenges over the years due to the high magnitude and short duration of the specifications. Recently, component structural failures have occurred during testing that have not manifested themselves on over 200 Space Shuttle solid rocket booster (SRB) flights (two boosters per flight). It is suspected that the method of specifying shock test criteria may be leaving important information out of the test process. The traditional test criteria specification, the shock response spectrum, can be duplicated by any number of waveforms that may not resemble the actual flight test recorded time history. One method of overcoming this limitation is described herein, which may prove useful for qualifying hardware for the upcoming Constellation Program.

Ferebee, R. C.; Clayton, J.; Alldredge, D.; Irvine, T.

2008-01-01

381

Experimental test results from an environmental protection agency test method for determination of vapor suppressant effectiveness  

Microsoft Academic Search

The results obtained from laboratory experiments conducted using Environmental Protection Agency (EPA) subpart WWWW of 40 Code of Federal Regulations (CFR) part 63 (1)-test method are discussed in this article. The original test method was developed to measure the effectiveness of wax suppressants used to reduce hazardous air pollutant (HAP) emissions from unsaturated polyester (UP)\\/vinyl ester resins. Wax additions of

Richard W. Tock; Daniel W. Ahern

2005-01-01

382

Overview of multi-input frequency domain modal testing methods with an emphasis on sine testing  

NASA Technical Reports Server (NTRS)

An overview of the current state of the art multiple-input, multiple-output modal testing technology is discussed. A very brief review of the current time domain methods is given. A detailed review of frequency and spatial domain methods is presented with an emphasis on sine testing.

Rost, Robert W.; Brown, David L.

1988-01-01

383

Let your users do the testing: a comparison of three remote asynchronous usability testing methods  

Microsoft Academic Search

Remote asynchronous usability testing is characterized by both a spatial and temporal separation of users and evaluators. This has the potential both to reduce practical problems with securing user attendance and to allow direct involvement of users in usability testing. In this paper, we report from an empirical study where we systematically compared three methods for remote asynchronous usability testing:

Anders Bruun; Peter Gull; Lene Hofmeister; Jan Stage

2009-01-01

384

Pattern formation during fracture dissolution  

NASA Astrophysics Data System (ADS)

A number of experimental and numerical studies of dissolution in fractured and porous rocks have established that the evolving topography of the pore space depends strongly on the fluid flow and mineral dissolution rates. Remarkably, there exists a wide parameter range in which positive feedback between fluid transport and mineral dissolution leads to the spontaneous formation of pronounced channels, frequently referred to as "wormholes". As dissolution proceeds the growing channels interact, competing for the available flow, and eventually the growth of the shorter ones cease. This leads to self-similar patterns of growth, with the flow becoming concentrated in fewer active channels as the dissolution proceeds. Under some conditions it is reasonable to assume that the growth of the channels is proportional to the reactant flux near the tip of each channel. Since the pressure field in the rock matrix obeys the Laplace equation, the competition between the channels may then be described in terms of a Laplacian growth model and solved using conformal mapping techniques. The figures compare the flow field around two different length channels. The upper figure was obtained from a Reynold's approximation for a parabolic channel, while the lower figure is the conformal solution, assuming a constant pressure along the channel. The Reynold's solution shows the expected enhancement of flow through the longer channel, which leads to more rapid dissolution. The conformal solution, assuming a constant pressure along the channel is remarkably similar. Combining conformal mapping with Darcy-scale simulations, we study the interaction between a large number of growing channels and the resulting dissolution patterns. Flow field around two channels, determined from a Reynold's approximation. The flow direction is along the channels. Flow field around two channels, from a conformal mapping. The flow direction is along the channels

Szymczak, P.; Ladd, T.

2009-12-01

385

A study of short test and charge retention test methods for nickel-cadmium spacecraft cells  

NASA Technical Reports Server (NTRS)

Methods for testing nickel-cadmium cells for internal shorts and charge retention were studied. Included were (a) open circuit voltage decay after a brief charge, (b) open circuit voltage recovery after shorting, and (c) open circuit voltage decay and capacity loss after a full charge. The investigation included consideration of the effects of prior history, of conditioning cells prior to testing, and of various test method variables on the results of the tests. Sensitivity of the tests was calibrated in terms of equivalent external resistance. The results were correlated. It was shown that a large number of variables may affect the results of these tests. It is concluded that the voltage decay after a brief charge and the voltage recovery methods are more sensitive than the charged stand method, and can detect an internal short equivalent to a resistance of about (10,000/C)ohms where "C' is the numerical value of the capacity of the cell in ampere hours.

Scott, W. R.

1975-01-01

386

Testing Method for Heat Resistance Under Temperature Gradient  

Microsoft Academic Search

Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established\\u000a by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance\\u000a with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature\\u000a gradient of materials and coated members of equipment exposed to

K. Takagi; A. Kawasaki; Y. Itoh; Y. Harada; F. Ono

2007-01-01

387

EPA flow reference method testing and analysis: Findings report. Appendices  

SciTech Connect

In the summer of 1997, the US Environmental Protection Agency (EPA) conducted a series of week-long field tests at three electric utility sites to evaluate potential improvements to Method 2, EPA`s test method for measuring flue gas volumetric flow in stacks. The findings from that study are presented in document EPA/430-R-99-009a (NTIS Order Number PB99-150286). This document contains 10 appendices for that report.

NONE

1999-06-01

388

Nondestructive spot test method for magnesium and magnesium alloys  

NASA Technical Reports Server (NTRS)

A method for spot test identification of magnesium and various magnesium alloys commonly used in aerospace applications is described. The spot test identification involves color codes obtained when several drops of 3 M hydrochloric acid are placed on the surface to be tested. After approximately thirty seconds, two drops of this reacted acid is transferred to each of two depressions in a spot plate for additions of other chemicals with subsequent color changes indicating magnesium or its alloy.

Wilson, M. L. (inventor)

1973-01-01

389

An Enhanced Normalization Method for Dynamic Fracture Toughness Testing  

Microsoft Academic Search

Fracture toughness testing of ductile materials can be difficult in situations where it is not possible to measure crack extension\\u000a during the test, such as under high rate loading or in aggressive environments. In these situations, an alternative method\\u000a of inferring crack extension must be used to generate the tearing resistance curve, and thereby determine ductile crack initiation.\\u000a ASTM test

S. M. Graham; D. J. Stiles

390

A Conditional Exposure Control Method for Multidimensional Adaptive Testing  

ERIC Educational Resources Information Center

In computerized adaptive testing (CAT), ensuring the security of test items is a crucial practical consideration. A common approach to reducing item theft is to define maximum item exposure rates, i.e., to limit the proportion of examinees to whom a given item can be administered. Numerous methods for controlling exposure rates have been proposed…

Finkelman, Matthew; Nering, Michael L.; Roussos, Louis A.

2009-01-01

391

In vitro methods for antifungal susceptibility testing of Trichophyton spp  

Microsoft Academic Search

In general, methods to test the susceptibility of fungi to antifungal drugs require standardized techniques, but so far there is no methodology that is widely applicable to dermatophytes. Here we introduced modifications to the protocols from documents of the National Committee for Clinical Laboratory Standards (CLSI) M38-A and the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility

Maria Elisabete da Silva Barros; Daniel de Assis Santos; Júnia Soares Hamdan

2006-01-01

392

Light-scattering methods for antibiotic sensitivity tests  

Microsoft Academic Search

The total intensity of light scattered in the angular range 30 degrees-130 degrees by a suspension of bacteria can be used as the basis of a method of antibiotic sensitivity testing. A procedure is given in which the bacteria are incubated in the presence of antibiotic, as a test, and in its absence, as a control, for 60 minutes. An

J Murray; P Evans; D W Hukins

1980-01-01

393

Methods for testing antibiotic sensitivity of anaerobic bacteria  

Microsoft Academic Search

Summary Problems are still encountered in the performance and interpretation of tests of anaerobe sensitivity to antibiotics. A review of the methods currently used was carried out in order to determine factors modifying the activity of antibiotics. The sensitivity ofEscherichia coli, Staphylococcus aureus andClostridium perfringens to various drugs was tested under different conditions (including different culture media and incubation atmospheres).

J. A. Garctikyaa-Rodriguez; J. E. Garctikyaa-Sánchez; J. Prieto-Prieto

1980-01-01

394

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

395

Development of Test Methods and Draft Standard for Cardiac Monitors.  

National Technical Information Service (NTIS)

This report contains an overview of the work done in developing various versions of a standard for cardiac monitors, heart rate meters and alarms. It includes a summary of tests performed on commercial monitors by UBTL to evaluate the test methods propose...

A. A. Schoenberg A. R. Grahn H. E. Booth

1978-01-01

396

Computational method for testing computer-generated holograms  

Microsoft Academic Search

A procedure based entirely on computer simulation is developed for testing the quality of computer-generated holographic optical elements (CGHOEs). This new testing method may be of help in optimization techniques in the future. We introduce a mathematical quantity, the correlation, to characterize the performance of the studied CGHOE. Our procedure examines how the correlation between the object and the reconstructed

Nandor Bokor; Zsolt Papp

1996-01-01

397

A digital image correlation method for fatigue test experiments  

Microsoft Academic Search

In this paper, a method based on the digital image correlation (DIC) technique is proposed to monitor the crack growth process during a cyclic fatigue test. Stroboscopic illumination is used to acquire DIC speckle pattern images while the test sample is dynamically loaded. The proposed DIC algorithm uses the fact that the load is periodic to increase the accuracy of

Steve Vanlanduit; Joris Vanherzeele; Roberto Longo; Patrick Guillaume

2009-01-01

398

An evaluation of the whole effluent toxicity test method  

SciTech Connect

Whole effluent toxicity (WET) testing has become increasingly more important to the Environmental Protection Agency (EPA) and the States in the permitting of wastewater discharges from industry and municipalities. The primary purpose of the WET test is to protect aquatic life by predicting the effect of an effluent on the receiving stream. However, there are both scientific and regulatory concerns that using WET tests to regulate industrial effluents may result in either false positives and/or false negatives. In order to realistically predict the effect of an effluent on the receiving stream, the test should be as representative as possible of the conditions in the receiving stream. Studies (Rand and Petrocelli 1985) suggested several criteria for an ideal aquatic toxicity test organism, one of which is that the organism be indigenous to, or representative of, the ecosystem receiving the effluent. The other component needed in the development of a predictive test is the use of the receiving stream water or similar synthetic water as the control and dilution water in the test method. Use of an indigenous species and receiving water in the test should help reduce the variability in the method and allow the test to predict the effect of the effluent on the receiving stream. The experience with toxicity testing at the Savannah River Site (SRS) has yielded inconclusive data because of the inconsistency and unreliability of the results. The SRS contention is that the WET method in its present form does not adequately mimic actual biological/chemical conditions of the receiving streams and is neither reasonable nor accurate. This paper discusses the rationale for such a position by SRS on toxicity testing in terms of historical permitting requirements, outfall effluent test results, standard test method evaluation, scientific review of alternate test species, and concerns over the test method expressed by other organizations. This paper presents the Savannah River Site position that the EPA test is neither reasonable nor accurate and thus cannot adequately establish the impact of NPDES outfall discharges on receiving streams.

Osteen, D.V.

1999-12-17

399

Multipoint dissolution specification and acceptance sampling rule based on profile modeling and principal component analysis.  

PubMed

In dissolution testing, multiple dissolution measurements at specific time points are needed in quality control when the compliance of the product requires controlled dissolution throughout the time course. The dissolution specification based on general multivariate confidence region was proposed by Chen and Tsong (8). This paper presents two alternative procedures when the dissolution profile consists of important measurements at more than 4 time points. In the first procedure, when the dissolution profile can be described by a physical curve through modeling, the dissolution specification is developed based on the confidence region of the parameters of the physical curve. In the second procedure, the principal components (PCS) as the linear combinations of the dissolution measurements are identified and dissolution specification is set based by the confidence intervals of the values of principal components. In both approaches the specification can be set at lower dimensions than the general multivariate confidence region approach. A single-stage acceptance rule can be used in both approaches by first projecting the dissolution values of each tablet in the new testing batch onto the determined parameters axes (through modeling in modeling approach and through projection on the selected PCS in principal component approach). Then check if the projections of the new tablet fall within the specifications. Finally, count the number of tablets that fall outside the specification limits and reject the batch if the proportion of out-of-specification tablet is high and accept the lot for release if the proportion is low. PMID:9252835

Tsong, Y; Hammerstrom, T; Chen, J J

1997-07-01

400

Coamorphous repaglinide-saccharin with enhanced dissolution.  

PubMed

Recently, coamorphous systems composed of two drugs or a drug and a small molecule excipient, gained interests due to their ability in overcoming limitations associated with solid dispersions. In this study, coamorphous form of repaglinide (REP), a BCS class II anti-diabetic drug with low aqueous solubility and high permeability was achieved with saccharin (SAC) by solution crystallization and characterized. An accurate and precise HPLC method was established for the simultaneous determination of REP and SAC. Coamorphous REP-SAC with 1:1 stoichiometry had unique thermal behavior, obvious FTIR shifts and the absence of sharp diffraction peak, suggesting the formation of a coamorphous material and interaction of REP with SAC through hydrogen bonds formed between REP's secondary amine and SAC's carbonyl group. Coamorphous REP-SAC showed great improvement in solubility and dissolution under sink conditions in various media. In addition, it was conformed in supersaturated dissolution of coamorphous REP-SAC in distilled water that the coamorphous material had remarkably longer time length for REP to be remained at a supersaturated concentration and had better metastable solubility. This coamorphous system provides a feasible way to process drugs with low solubility into substances with enhanced dissolution and stabilized amorphous state that could be conducive to greater bioavailability than the crystalline drug. PMID:23612357

Gao, Yuan; Liao, Jiao; Qi, Xuan; Zhang, Jianjun

2013-06-25

401

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

402

Method and apparatus for tensile testing of metal foil  

NASA Technical Reports Server (NTRS)

A method for obtaining accurate and reproducible results in the tensile testing of metal foils in tensile testing machines is described. Before the test specimen are placed in the machine, foil side edges are worked until they are parallel and flaw free. The specimen are also aligned between and secured to grip end members. An aligning apparatus employed in the method is comprised of an alignment box with a longitudinal bottom wall and two upright side walls, first and second removable grip end members at each end of the box, and a means for securing the grip end members within the box.

Wade, O. W. (inventor)

1976-01-01

403

The Rocketdyne multifunction tester. Part 1: Test method  

NASA Technical Reports Server (NTRS)

The Rocketdyne Multifunction Tester is a general purpose test apparatus which utilizes axial and radial magnetic bearings as shaft excitation devices. The tester is modular in design so that different seal and bearing packages can be tested on the same test stand. The tester will be used for rotordynamic coefficient extraction, as well as life and fluid/material compatibility evaluations. Use of a magnetic bearing as a shaft excitation device opens up many possibilities for shaft excitation and rotordynamic coefficient extraction. In addition to describing the basic apparatus, some of the excitation and extraction methods are described. Some of the excitation methods to be discussed include random, aperiodic, harmonic, impulse and chirp.

Murphy, Brian T.; Scharrer, Joseph K.; Sutton, Robert F.

1991-01-01

404

Summarizing Change in Test Scores: Shortcomings of Three Common Methods.  

ERIC Educational Resources Information Center

Discusses the advantages and disadvantages of three commonly used methods for summarizing change in test scores: (1) change in percentile rank; (2) scale or raw score change; and (3) percent change. In general, these methods are insensitive to the measurement scale on which scores are expressed and perform mathematical operations that are…

Russell, Michael

2000-01-01

405

An Analytical Procedure for the Equipercentile Method of Equating Tests.  

ERIC Educational Resources Information Center

Prior use of the equipercentile method of test equating was based on a graphic procedure which is tedious, subject to smoothing errors, and non-analytical. Recognition of the equipercentile method as a curve-fitting procedure for two cumulative percentage distributions leads to a proposed analytical solution to the problem through use of linear…

Lindsay, Carl A.; Prichard, Mark A.

406

A\\/D Converters Testing Based on Beat Frequency Method  

Microsoft Academic Search

In this paper we present the capability of the beat frequency method to estimate ADC dynamic performance parameters. This task has been done by means of one of the most important dynamic parameter of an ADC - the effective number of bits (ENOB). An algorithm for estimating the ENOB of an ADC tested using the beat frequency method is proposed.

Daniel Belega; D. Dallet

2005-01-01

407

A New Method of Testing High Reliability Bridgewire Explosive Initiator  

Microsoft Academic Search

Based on the defects of the traditional methods to be used in selecting the quality of the bridgewire explosive device, a non-destructive selecting technology is given by the author in this paper. After the author introduced the development and application of this product, the key parameters to its quality are shown and the testing method is introduced. It is transient

Tian Chunlei; Gao Junguo; Zhang Li

2007-01-01

408

40 CFR 60.547 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...method for determination of the flow rate of the stack gas. The...used as the test method for the concurrent determination of gas flow rate in the capture system...least 1 hour. For each run, a concurrent sample shall be taken...

2009-07-01

409

40 CFR 60.547 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...method for determination of the flow rate of the stack gas. The...used as the test method for the concurrent determination of gas flow rate in the capture system...least 1 hour. For each run, a concurrent sample shall be taken...

2010-07-01

410

Automation Test Method for Automotive Embedded Software Based on AUTOSAR  

Microsoft Academic Search

This paper discusses new approach to materialize for automation test method for automotive embedded software. The total automotive embedded software is changing frequently whenever the specification for hardware is modified. These cause to spend time and cost. To resolve these problems, AUTOSAR which consists of the standardized interfaces, structures and communication method was introduced. AUTOSAR has Client-Server mechanism in order

Huichoun Moon; Gwanghun Kim; Yeongyun Kim; Seokkyoo Shin; Kyoung Kim; Im Sanggui

2009-01-01

411

Test program set software development using the rational Booch method  

Microsoft Academic Search

This paper discusses the use of the Booch object-oriented design method to model Test Program Set (TPS) software. A brief discussion of the Booch method will be provided. A discussion on how to define and create TPS objects is included. The discussion on modeling includes the analysis and design of the TPS architecture using the TPS objects. This paper also

Robert Czeranko; Tim Barrios

1996-01-01

412

40 CFR 63.786 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) National Emission Standards for Shipbuilding and Ship Repair (Surface Coating) § 63.786 Test methods and procedures...original sample. The sensitivity is defined as ten times the noise level as specified in ASTM Method D3257-93: Standard...

2013-07-01

413

Template occluded SBA-15: An effective dissolution enhancer for poorly water-soluble drug  

NASA Astrophysics Data System (ADS)

The aim of the present work was to improve the dissolution rate of piroxicam by inclusion into template occluded SBA-15. Our strategy involves directly introducing piroxicam into as-prepared SBA-15 occluded with P123 (EO 20PO 70EO 20) by self assembling method in acetonitrile/methylene chloride mixture solution. Ultraviolet spectrometry experiment and thermogravimetric analysis-differential scanning calorimetry (TG-DSC) profiles show that the piroxicam and P123 contents in the inclusion compound are 12 wt% and 28 wt%, respectively. X-ray powder diffraction and DSC analysis reveal that the included piroxicam is arranged in amorphous form. N 2 adsorption-desorption experiment indicates that the piroxicam has been introduced to the mesopores instead of precipitating at the outside of the silica material. The inclusion compound was submitted to in vitro dissolution tests, the results show that the piroxicam dissolve from template occluded inclusion compound more rapidly, than these from the piroxicam crystalline and template removed samples in all tested conditions. Thus a facile method to improve the dissolution rate of poorly water-soluble drug was established, and this discovery opens a new avenue for the utilization of templates used for the synthesis of mesoporous materials.

Tingming, Fu; Liwei, Guo; Kang, Le; Tianyao, Wang; Jin, Lu

2010-09-01

414

NNWSI waste form test method for unsaturated disposal conditions  

SciTech Connect

A test method has been developed to measure the release of radionuclides from the waste package under simulated NNWSI repository conditions, and to provide information concerning materials interactions that may occur in the repository. Data are presented from Unsaturated testing of simulated Savannah River Laboratory 165 glass completed through 26 weeks. The relationship between these results and those from parametric and analog testing are described. The data indicate that the waste form test is capable of producing consistent, reproducible results that will be useful in evaluating the role of the waste package in the long-term performance of the repository. 6 refs., 7 figs., 5 tabs.

Bates, J.K.; Gerding, T.J.

1985-03-01

415

Methodical aspects of text testing in a driving simulator.  

PubMed

A test with 30 test persons was conducted in a driving simulator. The test was a concept exploration and comparison of existing user interaction technologies for text message handling with focus on traffic safety and experience (technology familiarity and learning effects). Focus was put on methodical aspects how to measure and how to analyze the data. Results show difficulties with the eye tracking system (calibration etc.) per se, and also include the subsequent raw data preparation. The physical setup in the car where found important for the test completion. PMID:22317503

Sundin, A; Patten, C J D; Bergmark, M; Hedberg, A; Iraeus, I-M; Pettersson, I

2012-01-01

416

Application of various bod test methods in landfill leachates.  

PubMed

This study examined the determination of BOD in landfill leachates by dilution (D-Method) and manometric methods (M-Method). The discrepancies between these methods were discussed and statistical tests were carried out. The effects of sample dilution and seeding on BOD results were examined. In comparison to the D-Method the M-Method was found to be more sensitive to increases in chloride and Total Kjeldahl Nitrogen (TKN) concentrations in leachate samples. However, in the M-Method the positive interference of nitrogenous BOD (NBOD) to carbonaceous BOD (CBOD) was more successfully prevented. The BOD rate constant k and the ultimate BOD (BODu) were estimated by non-linear regression. With the M-Method these parameters could be more reliably estimated than the D-Method. Based on these results, suggestions were made for BOD analyses in landfill leachates in future studies. PMID:11413838

Ceçen, F; Yangin, C

2001-01-01

417

Drinking water test methods in crisis-afflicted areas: comparison of methods under field conditions.  

PubMed

To simplify the testing of drinking water in crisis-afflicted areas (as in Kosovo in 2007), rapid test methods were compared with the standard test. For Escherichia coli and coliform pathogens, rapid tests were made available: Colilert(®)-18, P/A test with 4-methylumbelliferyl-?-D-glucoronid, and m-Endo Broth. Biochemical differentiation was carried out by Enterotube™ II. Enterococci were determined following the standard ISO test and by means of Enterolert™. Four hundred ninety-nine water samples were tested for E. coli and coliforms using four methods. Following the standard method, 20.8% (n=104) of the samples contained E. coli, whereas the rapid tests detected between 19.6% (m-Endo Broth, 92.0% concordance) and 20.0% (concordance: 93.6% Colilert-18 and 94.8% P/A-test) positive samples. Regarding coliforms, the percentage of concordant results ranged from 98.4% (P/A-test) to 99.0% (Colilert-18). Colilert-18 and m-Endo Broth detected even more positive samples than the standard method did. Enterococci were detected in 93 of 573 samples by the standard method, but in 92 samples by Enterolert (concordance: 99.5%). Considering the high-quality equipment and time requirements of the standard method, the use of rapid tests in crisis-afflicted areas is sufficiently reliable. PMID:21854264

Merle, Roswitha; Bleul, Ingo; Schulenburg, Jörg; Kreienbrock, Lothar; Klein, Günter

2011-11-01

418

Equipment and Methods for Cryogenic Thermal Insulation Testing  

NASA Astrophysics Data System (ADS)

The study and evaluation of cryogenic thermal insulation materials and systems is a technology focus area of the Cryogenics Testbed at NASA Kennedy Space Center. The liquid nitrogen evaporation method is used between boundary temperatures of about 300 kelvin (K) and 77 K to make accurate measurements of the heat transfer rates and apparent thermal conductivity values (k-values) through different insulation systems. The methods include thermal performance characterization over the full range of pressures from high vacuum to no vacuum. Innovations include the design and development of three types of research test cryostats. The novel cryostats include absolute k-value for cylindrical specimens, comparative k-value for cylindrical specimens, and comparative k-value for flat specimens (including compressive loading). The material specimens may be in forms such as bulk fill, flat panel, multilayer, or continuously rolled. These new test methods are shown to be complementary to other established test methods.

Fesmire, J. E.; Augustynowicz, S. D.; Heckle, K. W.; Scholtens, B. E.

2004-06-01

419

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

420

Novel method for disk run-out testing  

NASA Astrophysics Data System (ADS)

We raised a novel method to test radial run-out of optical disc. The method measures run-out by track-across signal when optical head keeps focusing on rotating disc and stops in radial direction. The track-across signal can be picked up from commercial disc drive. Then the distance of passed tracks is calibrated by linear gratings. The advantages of this method are low-cost and high accuracy.

Huang, Jun; Pei, Xiandeng; Xie, Changsheng; Liu, Benxi

1998-12-01

421

A Simple Method for Determining Specific Yield from Pumping Tests  

USGS Publications Warehouse

A simpler solution which greatly reduces the time necessary to compute the specific yield by the pumping-test method of Remson and Lang (1955) is presented. The method consists of computing the volume of dewatered material in the cone of depression and comparing it with the total volume of discharged water. The original method entails the use of a slowly converging series to compute the volume of dewatered material. The solution given herein is derived directly from Darcy's law.

Ramsahoye, L. E.; Lang, Solomon Max.

1961-01-01

422

Monooctanoin use for gallstone dissolution.  

PubMed

Monooctanoin (Capmul 8210), a digestion product of medium chain triglycerides, is a cholesterol solvent that has been used for the dissolution of retained cholesterol gallstones following cholecystectomy. Bile duct infusion of monooctanoin is associated with little toxicity, although potentially serious problems can result from absorption of the drug or tissue infiltration. Gastrointestinal side effects such as anorexia, nausea, vomiting, diarrhea, and abdominal pain have been reported most commonly. Complete gallstone dissolution has occurred in approximately 50-75 percent of patients receiving monooctanoin. Although mechanical stone removal is still considered to be the treatment of choice for retained gallstones, monooctanoin use appears promising for stone dissolution in patients in whom mechanical removal has been unsuccessful or is impossible. PMID:3902430

Abate, M A; Moore, T L

1985-10-01

423

Dissolution of Plutonium Metal Using a HAN Process  

Microsoft Academic Search

Thermal stability tests were conducted with a nitric acid (HNO3)\\/hydroxylammonium nitrate (HAN)\\/potassium fluoride (KF) solution. The solution has great potential for use in plutonium dissolution because of the small quantity of hydrogen and other offgases produced. Tests were carried out in a Reactive Systems Screening Tool (RSST). The RSST is a calorimeter equipped with temperature and pressure probes as well

2004-01-01

424

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

425

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

426

[Comparative diagnostic value of Helicobacter pylori infection testing methods].  

PubMed

In 213 patients with gastric and duodenal pathology, including received surgery, comparative estimation of results of Helicobacter pylori (Hp) infection testing with invasive and noninvasive methods, were performed. Material for invasive endoscopic biopsy test (EBT), including rapid urease test (RUT) for rapid Hp identification by determination of urease activity, smear cytology and histology was extracted on endoscopy or intraoperationally. RUT was carried out with the help of URE-HP test kit. Serological test for Hp antibodies IgG and IgA class was performed by IFA using kit ELISA. 13? urea breath test (UBT) was made by determination of 13/12CO2 in breath samples on infrared spectroscope. Based on 5 different methods of Hp infection testing Hp positivity in 172 (80,8%) and Hp negativity in 41 (19,2%) from 213 examined patients was revealed. 13?-UBT revealed the highest diagnostic value (accuracy-97,5%, sensibility-97,0%, specificity-100%) in Hp infection diagnostics. In treatment efficiency control this parameters of 13?-UBT are also much high (96,7%, 90,0% and 100% respectively). In spite of high sensitivity of serological test (100%), it had comparative low specificity (71,0%) with high probability of false positive results in treated patients (antibodies titer to Hp after eradication retains for a long time). Thought, this test may be successfully used only in primary patients and in epidemiological studies. Among three methods of EBT, Hp infection detection with RUT revealed the best results (accuracy-94,8%, sensibility-95,0%, specificity-100%). Correlation of RUT and UBT results and much higher diagnostic value of UBT, necessitate RUT with histological study of stomach body mucosa to perform in patients over 45 year, with prolonged anamnesis and dangerous symptoms of disease. In Hp positive patients correlation of index DOB‰ of breath test with results of RUT was revealed. This can serve the index DOB‰ of 13?-UBT as a marker of Hp infection rate. The (accuracy, sensibility and specificity of breath test with local made 13?-urea (98,7%, 98,5% and 100% respectively) are the same as those for BT with standard 13?-urea (96,7%, 96,2% and 100% respectively). Above mentioned, 13?-UBT advantages (noninvasiveness, simplicity, rapidity, safety) and high diagnostic value exceeding same of other applied tests, give us opportunity to offer 13?-UBT as screening method of Hp infection diagnosis and a method of choise in control of Hp infection treatment efficiency. PMID:24423677

2013-12-01

427

Standard Methods for Bolt-Bearing Testing of Textile Composites  

NASA Technical Reports Server (NTRS)

The response of three 2-D braided materials to bolt bearing loading was evaluated using data generated by Boeing Defense and Space Group in Philadelphia, PA. Three test methods, stabilized single shear, unstabilized single shear, and double shear, were compared. In general, these textile composites were found to be sensitive to bolt bearing test methods. The stabilized single shear method yielded higher strengths than the unstabilized single shear method in all cases. The double shear test method always produced the highest strengths but these results may be somewhat misleading. It is therefore recommended that standard material comparisons be made using the stabilized single shear test method. The effects of two geometric parameters, W/D and e/D, were also studied. An evaluation of the effect of the specimen width (W) to hole diameter (D) ratio concluded that bolt bearing responses were consistent with open hole tension results. A W/D ratio of 6 or greater should be maintained. The proximity of the hole to the specimen edge significantly affected strength. In all cases, strength was improved by increasing the ratio of the distance from the hole center to the specimen edge (e) to the hole diameter (D) above 2. An e/D ratio of 3 or greater is recommended.

Portanova, M. A.; Masters, J. E.

1995-01-01

428

Development of fire test methods for airplane interior materials  

NASA Technical Reports Server (NTRS)

Fire tests were conducted in a 737 airplane fuselage at NASA-JSC to characterize jet fuel fires in open steel pans (simulating post-crash fire sources and a ruptured airplane fuselage) and to characterize fires in some common combustibles (simulating in-flight fire sources). Design post-crash and in-flight fire source selections were based on these data. Large panels of airplane interior materials were exposed to closely-controlled large scale heating simulations of the two design fire sources in a Boeing fire test facility utilizing a surplused 707 fuselage section. Small samples of the same airplane materials were tested by several laboratory fire test methods. Large scale and laboratory scale data were examined for correlative factors. Published data for dangerous hazard levels in a fire environment were used as the basis for developing a method to select the most desirable material where trade-offs in heat, smoke and gaseous toxicant evolution must be considered.

Tustin, E. A.

1978-01-01

429

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

2010-01-01

430

Applicability of ultrasonic testing for the determination of volume fraction of particulates in alumina-reinforced aluminum matrix composites  

SciTech Connect

An ultrasonic testing technique was employed to determine the volume fraction of alumina particulate reinforcement in 6061 aluminum matrix composites. this study was performed on various composites with Al{sub 2}O{sub 3} nominal volume fractions of 10, 15, and 20