These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Mathematical methods for quantification and comparison of dissolution testing data.  

PubMed

In recent years, drug release/dissolution from solid dosage forms has been the subject of intense and profitable scientific developments. Whenever a new solid dosage form is developed or produced, it is necessary to ensure that drug dissolution occurs in an appropriate manner. The pharmaceutical industry and the registration authorities do focus, nowadays, on drug dissolution studies. The quantitative analysis of the values obtained in dissolution/release tests is easier when mathematical formulas that express the dissolution results as a function of some of the dosage forms characteristics are used. This work discusses the analysis of data obtained for dissolution profiles under different media pH conditions using mathematical methods of analysis described by Moore and Flanner. These authors have described difference factor (f1) and similarity factor (f2), which can be used to characterise drug dissolution/release profiles. In this work we have used these formulas for evaluation of dissolution profiles of the conventional tablets in different pH of dissolution medium (range of physiological variations). PMID:16212566

Vrani?, Edina; Mehmedagi?, Aida; Hadzovi?, Sabira

2002-12-01

2

Dissolution testing of acetylsalicylic acid by a channel flow method—correlation to USP basket and intrinsic dissolution methods  

Microsoft Academic Search

A new modification of the channel flow dissolution method is introduced together with the theoretical basis to extract the solubility and mass transfer parameters from the dissolution experiments. Correlation of drug dissolution profiles in the channel flow apparatus was evaluated with respect to USP basket and intrinsic dissolution methods at pH 1.2 or 6.8. Acetylsalicylic acid (ASA) was studied as

Leena Peltonen; Peter Liljeroth; Tiina Heikkilä; Kyösti Kontturi; Jouni Hirvonen

2003-01-01

3

An alternative method to the evaluation of similarity factor in dissolution testing.  

PubMed

This paper addresses an alternative method to the evaluation of similarity factor f(2) as a criterion for assessment of similarity between two in-vitro dissolution profiles as proposed in the SUPAC-IR Guidance (1995). Diltiazem hydrochloride Sustained-Release (SR) tablets were tested and the following independent-model dissolution parameters were used: t10% dissolution time, t25% dissolution time, t50% dissolution time, mean dissolution time (MDT), dissolution efficiency (DE) at t(120), and at t(360). To compare the dissolution profiles, several release models were tested such as Higuchi, zero order, first order, Baker-Lonsdale, Hixson-Crowell, Weibull and Korsmeyer-Peppas. The similarities between two in-vitro dissolution profiles were assessed by pair-wise independent-model procedures such as difference factor (f1), similarity factor (f2) and Rescigno index (xi1 and xi2). The in vitro release kinetics of diltiazem hydrochloride sustained release tablets were evaluated using USP apparatus 2. PMID:11376969

Costa, P

2001-06-01

4

Development and validation of a dissolution test method for vitamin A in dietary supplement tablets.  

PubMed

A dissolution test method and an analytical procedure by HPLC were developed and validated for evaluation of the dissolution behavior of dietary supplements tablets containing vitamin A in the forms of retinyl acetate or retinyl palmitate. Seven different commercially available products containing retinyl acetate or retinyl palmitate were selected for this study. A dissolution medium containing 1% (w/v) Octoxynol 9 (Triton X-100) and 1% (w/v) (+)-sodium alpha-ascorbate in 0.05 M phosphate buffer, pH 6.8, was found suitable to ensure sink conditions and chemical stability for both retinyl acetate and retinyl palmitate. Two rotation speeds, 50 and 75 rpm, were evaluated with USP Apparatus 2 and 900 ml dissolution medium. Dissolution profiles were generated over 120 min. Dissolution samples were analyzed with a reversed-phase HPLC method with UV detection at 325 nm. Each product was also assayed for vitamin A content according to USP 32-NF 27. The results from 45 min to the last time point of the dissolution tests performed at 75 rpm were consistent with the Assay results. The dissolution test described here could be proposed as a pharmacopeial standard to assess the performance of tablet formulations containing vitamin A as retinyl esters. PMID:20427140

Davydova, Natalia; Stippler, Erika; Jin, Ping; Giancaspro, Gabriel

2010-11-01

5

Saltcake Dissolution Simulant Tests  

SciTech Connect

Small-scale (15 to 50 mL) dissolution equilibrium tests were performed on surrogate waste representing typical saltcake at the Savannah River and Hanford Sites. The primary objectives of this study were to gain a better understanding of the solid-liquid equilibrium of simulated-waste saltcakes and chemistry of the dissolved salt solutions. These tests were performed in preparation for similar dissolution tests with actual-waste saltcakes. Two types of tests (single-wash and multiple-wash) were performed at two temperatures (25 degrees Celsius and 50 degrees Celsius) for each saltcake simulant. The compositions of the supernatant fluids are provided for both types of dissolution tests, and profiles of the elution of each salt component are provided for the multiple-wash tests. The conclusions from these tests follow: (1) For both salt waste surrogates, dissolution of the soluble components was achieved at less than a 2:1 mass ratio of inhibited water to saltcake during multiple-wash tests., (2) Dissolution of the Hanford S-112 simulant resulted in a relatively large weight percentage of residual insoluble material (4.2 wt. percent), which was identified as a mixture of Al(OH)3 phases (bayerite and gibbsite)., and (3) The profiles for the relative elution of anions from saltcake during dissolution exhibit distinctions that are dependent upon the dissolution temperature and the initial saltcake composition.

Martino, C.J.

2003-02-18

6

Reciprocating dialysis tube method: Periodic tapping improved in vitro release\\/dissolution testing of suppositories  

Microsoft Academic Search

The reciprocating dialysis tube (RDT) method can be used for in vitro release\\/dissolution testing of suppositories and has been reported to show good in vitro and in vivo correlation. However, for suppositories with viscous excipients, the result remains variable and generally under-predicts in vivo absorption. The purpose of this study was to assess whether periodic tapping of the closure of

Soichi Itoh; Naomi Teraoka; Toshio Matsuda; Kousuke Okamoto; Tatsuya Takagi; Charles Oo; H. Danny Kao

2006-01-01

7

Standard practice for measurement of the glass dissolution rate using the single-pass flow-through test method  

E-print Network

1.1 This practice describes a single-pass flow-through (SPFT) test method that can be used to measure the dissolution rate of a homogeneous silicate glass, including nuclear waste glasses, in various test solutions at temperatures less than 100°C. Tests may be conducted under conditions in which the effects from dissolved species on the dissolution rate are minimized to measure the forward dissolution rate at specific values of temperature and pH, or to measure the dependence of the dissolution rate on the concentrations of various solute species. 1.2 Tests are conducted by pumping solutions in either a continuous or pulsed flow mode through a reaction cell that contains the test specimen. Tests must be conducted at several solution flow rates to evaluate the effect of the flow rate on the glass dissolution rate. 1.3 This practice excludes static test methods in which flow is simulated by manually removing solution from the reaction cell and replacing it with fresh solution. 1.4 Tests may be conducted wit...

American Society for Testing and Materials. Philadelphia

2010-01-01

8

Development of dissolution tests for oral extended-release products  

Microsoft Academic Search

Dissolution testing is well established in pharmaceutical compendia as a means of assessing finished product quality. Oral extended-release products present unique challenges in the development of dissolution test methods for their characterization. Although the current focus in the field has been on the use of dissolution testing in the later stages of product development for the purpose of establishing in

Ellen D Jorgensen; Dileep Bhagwat

1998-01-01

9

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

10

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

11

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

12

A multivariate test for similarity of two dissolution profiles.  

PubMed

A multivariate test of size a for assessing the similarity of two dissolution profiles is proposed. The inferential procedure is developed by using the approach for the common mean problem in a multivariate setup due to Halperin (1961). The performance of the proposed method is compared with Intersection Union Test as well as f2 criterion recommended by the FDA through a simulation study. All the methods are illustrated with real examples. PMID:15796294

Saranadasa, H; Krishnamoorthy, K

2005-01-01

13

21 CFR 343.90 - Dissolution and drug release testing.  

Code of Federal Regulations, 2011 CFR

...343.90 Dissolution and drug release testing. (a) [Reserved] (b) Aspirin capsules. Aspirin capsules must meet the dissolution standard for aspirin capsules as contained in the United States Pharmacopeia (USP) 23 at page...

2011-04-01

14

21 CFR 343.90 - Dissolution and drug release testing.  

...343.90 Dissolution and drug release testing. (a) [Reserved] (b) Aspirin capsules. Aspirin capsules must meet the dissolution standard for aspirin capsules as contained in the United States Pharmacopeia (USP) 23 at page...

2014-04-01

15

21 CFR 343.90 - Dissolution and drug release testing.  

Code of Federal Regulations, 2012 CFR

...343.90 Dissolution and drug release testing. (a) [Reserved] (b) Aspirin capsules. Aspirin capsules must meet the dissolution standard for aspirin capsules as contained in the United States Pharmacopeia (USP) 23 at page...

2012-04-01

16

21 CFR 343.90 - Dissolution and drug release testing.  

Code of Federal Regulations, 2010 CFR

...343.90 Dissolution and drug release testing. (a) [Reserved] (b) Aspirin capsules. Aspirin capsules must meet the dissolution standard for aspirin capsules as contained in the United States Pharmacopeia (USP) 23 at page...

2010-04-01

17

21 CFR 343.90 - Dissolution and drug release testing.  

Code of Federal Regulations, 2013 CFR

...343.90 Dissolution and drug release testing. (a) [Reserved] (b) Aspirin capsules. Aspirin capsules must meet the dissolution standard for aspirin capsules as contained in the United States Pharmacopeia (USP) 23 at page...

2013-04-01

18

Automated Dissolution for Enteric-Coated Aspirin Tablets: A Case Study for Method Transfer to a RoboDis II.  

PubMed

Dissolution method transfer is a complicated yet common process in the pharmaceutical industry. With increased pharmaceutical product manufacturing and dissolution acceptance requirements, dissolution testing has become one of the most labor-intensive quality control testing methods. There is an increased trend for automation in dissolution testing, particularly for large pharmaceutical companies to reduce variability and increase personnel efficiency. There is no official guideline for dissolution testing method transfer from a manual, semi-automated, to automated dissolution tester. In this study, a manual multipoint dissolution testing procedure for an enteric-coated aspirin tablet was transferred effectively and reproducibly to a fully automated dissolution testing device, RoboDis II. Enteric-coated aspirin samples were used as a model formulation to assess the feasibility and accuracy of media pH change during continuous automated dissolution testing. Several RoboDis II parameters were evaluated to ensure the integrity and equivalency of dissolution method transfer from a manual dissolution tester. This current study provides a systematic outline for the transfer of the manual dissolution testing protocol to an automated dissolution tester. This study further supports that automated dissolution testers compliant with regulatory requirements and similar to manual dissolution testers facilitate method transfer. PMID:24464812

Ibrahim, Sarah A; Martini, Luigi

2014-01-24

19

Characterization and Dissolution Kinetics Testing of Radioactive H-3 Calcine  

SciTech Connect

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

Garn, Troy Gerry; Batcheller, Thomas Aquinas

2002-09-01

20

Dissolution Testing for Generic Drugs: An FDA Perspective  

Microsoft Academic Search

In vitro dissolution testing is an important tool used for development and approval of generic dosage forms. The objective of this\\u000a article is to summarize how dissolution testing is used for the approval of safe and effective generic drug products in the\\u000a United States (US). Dissolution testing is routinely used for stability and quality control purposes for both oral and

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

21

Glass dissolution: testing and modeling for long-term behavior  

Microsoft Academic Search

The basic concepts of thermodynamics and kinetics are discussed in relationship to glass dissolution testing. While it seems like these subjects are too basic to be discussed in a journal article, it is often the case that we forget these concepts when planning and designing dissolution tests and interpreting the results that come from these tests. The possible connection between

Denis M. Strachan; Denis M

2001-01-01

22

Prediction of in vivo drug release behavior of controlled-release multiple-unit dosage forms in dogs using a flow-through type dissolution test method.  

PubMed

A newly designed flow-through type dissolution test method (FT method) was applied to predict in vivo drug release behaviors in dogs of controlled-release multiple unit dosage forms. The in vivo drug release behaviors were directly observed by measuring the residual amount of drugs in preparations recovered from the gastrointestinal (GI) tract after oral administration. Theophylline (TP), acetaminophen (AA), and phenylpropanolamine hydrochloride (PPA), which have different solubility, were used as model drugs. In vivo drug release behaviors in the gastrointestinal (GI) tract of dogs were similar to the results of the Wagner-Nelson method. In vivo release behaviors of TP and AA, until 2h after administration, were well correlated to in vitro behaviors obtained by the paddle method at 100 rpm. However, the in vivo release rates of TP and AA were gradually decreased because of a lack of fluid in the lower region of the GI tract, their poor solubility, the difference of the release rates, and so on. Non-sink conditions, which would reflect TP and AA release in the lower region of the GI tract, were obtained by the FT method at a cell volume of 0.5 ml and a flow rate of 0.37 ml/h (TP), 0.48 ml/h (AA), respectively. The in vitro release profiles obtained by the FT method combining sink and non-sink conditions were similar to their in vivo profiles. On the other hand, in the case of PPA, the in vivo release profiles were considerably similar to the in vitro ones obtained by both the paddle method and the FT method. In conclusion, the FT method combining sink and non-sink conditions will give a good in vitro/in vivo correlation regarding release behavior for controlled-release multiple unit dosage forms. PMID:12753751

Ikegami, Kengo; Tagawa, Kozo; Kobayashi, Masao; Osawa, Takashi

2003-06-01

23

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...

24

In situ dissolution testing using potentiometric sensors  

Microsoft Academic Search

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

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

2008-01-01

25

Optimization of dissolution test precision for a ketoprofen oral extended-release product  

Microsoft Academic Search

An example of application of experimental design methodologies to the set up of dissolution test conditions for a new ketoprofen oral extended-release dosage form is presented. The aim of the work was to find the best experimental conditions, using a USP apparatus 2 (paddle), for maximizing the method precision as degree of repeatability. The considered factors mainly influencing the dissolution

S Furlanetto; F Maestrelli; S Orlandini; S Pinzauti; P Mura

2003-01-01

26

IntersectionUnion Tests in Dissolution Profile Testing Jorge H. SierraCavazos  

E-print Network

Intersection­Union Tests in Dissolution Profile Testing Jorge H. Sierra­Cavazos Departamento de­union test, dissolution profile testing, normal population, t distribution, power, sample size. 1 against time in an in vitro experiment. A comparison of dissolution profiles between a test drug

27

Comparison of in vitro dissolution profiles by ANOVA-based, model-dependent and -independent methods.  

PubMed

In this study, the aim was to apply different comparison methods to dissolution profiles of immediate release commercial film-coated tablets of naproxen sodium in order to (1) evaluate each method in terms of easy application and usefulness and (2) identify the advantages and disadvantages of each method. Dissolution testing was conducted using the USP monograph of naproxen sodium. The applied methods for the comparison of in vitro dissolution profiles are ANOVA-based methods, model-dependent methods, and model-independent methods including difference factor, f(1), and similarity factor, f(2). All the methods appear to be applicable and useful in comparing dissolution profiles. The results show that ANOVA-based methods and model-dependent methods are more discriminative than the f-factors. f-Factors seem to be easier to apply and interpret; only one value is obtained to describe the closeness of the two dissolution profiles. However, a last point for dissolution had to be determined, since the values of the f-factors depend on this point. The application and evaluation of model-dependent methods are more complicated; these methods present an acceptable model approach to the true relationship between percent dissolved and time variables, including statistical assumptions which could be checked. Dissolution profiles can be tested for differences in both level and shape by ANOVA-based methods and these methods provide detailed information about dissolution data which can be useful also in formulation development to match release to a reference product. PMID:11084246

Yuksel, N; Kanik, A E; Baykara, T

2000-11-19

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

The automation of dissolution testing of solid oral dosage forms.  

PubMed

Dissolution testing of solid oral dosage forms plays a very important part both in the development of new products and in quality control. A fully automated system for dissolution testing known as AUTO DISS is presented and its components are described. On-line determination of active ingredient concentration is possible with the aid of an integrated automatic sampler in combination with various measuring instruments (UV-vis spectrometry, liquid chromatography and flow injection analysis). The suitability of the system is demonstrated by determination of the dissolution of brotizolam from tablets by FIA and of bepafant from capsules by diode-array spectroscopy. PMID:1298375

Lamparter, E; Lunkenheimer, C H

1992-01-01

30

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

31

A Quality by Design approach to investigate tablet dissolution shift upon accelerated stability by multivariate methods.  

PubMed

This paper presents the use of experimental design, optimization and multivariate techniques to investigate root-cause of tablet dissolution shift (slow-down) upon stability and develop control strategies for a drug product during formulation and process development. The effectiveness and usefulness of these methodologies were demonstrated through two application examples. In both applications, dissolution slow-down was observed during a 4-week accelerated stability test under 51°C/75%RH storage condition. In Application I, an experimental design was carried out to evaluate the interactions and effects of the design factors on critical quality attribute (CQA) of dissolution upon stability. The design space was studied by design of experiment (DOE) and multivariate analysis to ensure desired dissolution profile and minimal dissolution shift upon stability. Multivariate techniques, such as multi-way principal component analysis (MPCA) of the entire dissolution profiles upon stability, were performed to reveal batch relationships and to evaluate the impact of design factors on dissolution. In Application II, an experiment was conducted to study the impact of varying tablet breaking force on dissolution upon stability utilizing MPCA. It was demonstrated that the use of multivariate methods, defined as Quality by Design (QbD) principles and tools in ICH-Q8 guidance, provides an effective means to achieve a greater understanding of tablet dissolution upon stability. PMID:21168490

Huang, Jun; Goolcharran, Chimanlall; Ghosh, Krishnendu

2011-05-01

32

New Dissolution Method for Mesalamine Tablets and Capsules  

Microsoft Academic Search

Dissolution methods are different for extended-release mesalamine capsules (pH 7.5 only) and delayed-release tablets (pH 1.4, 6.0, and 7.2). Mesalamine is used for the treatment of ulcerative colitis. The USP methods have several drawbacks in that they do not mimic gastrointestinal tract environments; tablets are removed from vessels to change dissolution medium; and neither method has been adopted to compare

Monica C. Chuong; J. Mark Christensen; James W. Ayres

33

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

34

A new principal component analysis-based approach for testing "similarity" of drug dissolution profiles.  

PubMed

A new approach for testing batch "similarity" through comparison of drug dissolution profiles, based on principal component analysis with the establishment of a confidence region (PCA-CR), is presented. The dissolution curves corresponding to three brands each of Furosemide and Acetaminophen tablets, taken as model drugs, were prepared by dissolution measurements at multiple pre-specified time points. Reference and test data were simultaneously subjected to PCA and pairwise comparisons between the dissolution characteristics of lots of the same and different brands were carried out. The comparisons involved plotting the weighed scores of the first two principal components of reference and test lots, while decision about "similarity" was made by checking for inclusion of more than 80% of the tablets of the test lot in the 95% confidence ellipse of the reference samples. Two published datasets were also analyzed in the same fashion and all the results were compared with information provided by the difference (f1) and similarity (f2) factor tests. Unlike the f2 criterion, the proposed method reflects variability within the individual dissolution curves, being also highly sensitive to profile (shape and size) variations. Comparison between the area enclosed by the confidence ellipses of the weighed scores plot and the region obtained from the bootstrap-calculated acceptable values of the corresponding f2 tests suggested that PCA-CR represents, in general, a more discriminating standard. PMID:18394869

Maggio, Rubén M; Castellano, Patricia M; Kaufman, Teodoro S

2008-05-10

35

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

SciTech Connect

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

Ebert, W. L.; Chemical Engineering

2006-02-28

36

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

37

Combined approach of FTIR imaging and conventional dissolution tests applied to drug release  

Microsoft Academic Search

A new method is developed to study drug release using a combination of FTIR imaging and conventional dissolution tests. FTIR imaging in attenuated total reflection (ATR) mode allows simultaneous measurements of the distribution of different components in the tablet, e.g., drug, polymer and water as a function of time. These imaging measurements were carried out in a combined compaction and

Jaap van der Weerd; Sergei G Kazarian

2004-01-01

38

Clinical relevance of dissolution testing in quality by design.  

PubMed

Quality by design (QbD) has recently been introduced in pharmaceutical product development in a regulatory context and the process of implementing such concepts in the drug approval process is presently on-going. This has the potential to allow for a more flexible regulatory approach based on understanding and optimisation of how design of a product and its manufacturing process may affect product quality. Thus, adding restrictions to manufacturing beyond what can be motivated by clinical quality brings no benefits but only additional costs. This leads to a challenge for biopharmaceutical scientists to link clinical product performance to critical manufacturing attributes. In vitro dissolution testing is clearly a key tool for this purpose and the present bioequivalence guidelines and biopharmaceutical classification system (BCS) provides a platform for regulatory applications of in vitro dissolution as a marker for consistency in clinical outcomes. However, the application of these concepts might need to be further developed in the context of QbD to take advantage of the higher level of understanding that is implied and displayed in regulatory documentation utilising QbD concepts. Aspects that should be considered include identification of rate limiting steps in the absorption process that can be linked to pharmacokinetic variables and used for prediction of bioavailability variables, in vivo relevance of in vitro dissolution test conditions and performance/interpretation of specific bioavailability studies on critical formulation/process variables. This article will give some examples and suggestions how clinical relevance of dissolution testing can be achieved in the context of QbD derived from a specific case study for a BCS II compound. PMID:18686045

Dickinson, Paul A; Lee, Wang Wang; Stott, Paul W; Townsend, Andy I; Smart, John P; Ghahramani, Parviz; Hammett, Tracey; Billett, Linda; Behn, Sheena; Gibb, Ryan C; Abrahamsson, Bertil

2008-06-01

39

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

Microsoft Academic Search

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

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

2009-01-01

40

Review and critical analysis of available in vitro dissolution tests.  

PubMed

The procedures recommended in Publications 30 and 66 by ICRP for calculating radiation doses from inhaled or ingested radionuclides include classification of material on the basis of different parameters, among which transportability plays a major role, The allocation of transportable Classes or absorption Types should, whenever possible, be based on animal or human data. However, when such in vivo data are unavailable, it becomes appropriate to consider the use of other approaches, among which in vitro dissolution techniques are reasonable alternatives. This paper reviews and critically analyzes in vitro dissolution techniques that have been described historically and recommends methods shown to be useful in estimating the in vivo solubility of radioactive particles. PMID:10568542

Ansoborlo, E; Hengé-Napoli, M H; Chazel, V; Gibert, R; Guilmette, R A

1999-12-01

41

Evaluation of floating and sticking extended release delivery systems: an unconventional dissolution test  

Microsoft Academic Search

The extent to which hydrophilic matrix tablets with a propensity to stick to the dissolution apparatus and\\/or float are susceptible to variations in hydrodynamic conditions during dissolution testing was investigated. Furthermore the usefulness of simple alternatives to the current compendial tests is examined. Swellable hydrocolloid (guar) matrix tablets containing verapamil HCl were evaluated using USP dissolution apparatus I and II.

Thomas Dürig; Reza Fassihi

2000-01-01

42

Dissolution Testing as a Prognostic Tool for Oral Drug Absorption: Immediate Release Dosage Forms  

Microsoft Academic Search

Dissolution tests are used for many purposes in the pharmaceutical industry: in the development of new products, for quality control and, to assist with the determination of bioequivalence. Recent regulatory developments such as the Biopharmaceutics Classification Scheme have highlighted the importance of dissolution in the regulation of post-approval changes and introduced the possibility of substituting dissolution tests for clinical studies

Jennifer B. Dressman; Gordon L. Amidon; Christos Reppas; Vinod P. Shah

1998-01-01

43

Enzymes in the dissolution testing of gelatin capsules.  

PubMed

Gelatin capsules are a widely used dosage form both for pharmaceutical drug products as well as dietary supplements. Gelatin in the presence of certain compounds, mainly aldehydes, or in high humidity and high temperature conditions can cross-link. Cross-linking involves covalent bonding of the amine group of a lysine side chain of one gelatin molecule to a similar amine group on another molecule. The covalent bonding is, for practical purposes, irreversible. Cross-linking results in the formation of a pellicle on the internal or external surface of the gelatin capsule shell that prevents the capsule fill from being released. In vitro dissolution testing of cross-linked gelatin capsules can result in slower release of the drug or no release at all. The data obtained by the Gelatin Capsule Working Group, created in the early 90s to investigate noncompliance of gelatin capsules, was used to establish the type and amounts of enzymes that can be added to the dissolution medium in the case of test failure to the presence of cross-linking in the gelatin. The two-tier dissolution testing was included in the US Pharmacopeia and it recommends the addition of pepsin (pH below 6.8) or pancreatin (pH above 6.8) to the medium depending on its pH. Pepsin shows good protease activity up to pH 4 and pancreatin above pH 6 leaving a gap where neither one has good activity. Possible proteolytic enzymes that could be used for the pH range 4-6.8 could be papain or bromelain. PMID:24942315

Marques, Margareth R C

2014-12-01

44

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

PubMed

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

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

2013-11-20

45

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

PubMed

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

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

2012-11-01

46

Combined study of biphasic and zero-order release formulations with dissolution tests and ATR-FTIR spectroscopic imaging.  

PubMed

In this study of multi-layer tablets, the dissolution of biphasic and zero-order release formulations has been studied primarily using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic imaging as well as UV-Vis detection of dissolved drug in the effluent stream and USP dissolution testing. Bilayer tablets, containing the excipients microcrystalline cellulose (MCC) and glucose, were used for biphasic release with nicotinamide and buflomedil as model drugs. ATR-FTIR spectroscopic imaging showed the changing component distributions during dissolution. Further experiments studied monolithic and barrier-layered tablets containing hydroxypropyl methylcellulose, MCC and buflomedil dissolving in a USP I apparatus. These data were compared with UV-Vis dissolution profiles obtained online with the ATR flow-through cell. ATR-FTIR imaging data of the biphasic formulations demonstrated that the drug release was affected by excipient ratios and effects such as interference between tablet sections. Tablets placed in the ATR-FTIR flow-through cell exhibited zero-order UV-Vis dissolution profile data at high flow rates, similar to barrier-layered formulations studied using the USP I apparatus. ATR-FTIR spectroscopic imaging provided information regarding the dissolution mechanisms in multi-layer tablets which could assist formulation development. The ability to relate data from USP dissolution tests with that from the ATR-FTIR flow-through cell could help spectroscopic imaging complement dissolution methods used in the industry. PMID:24801351

Wray, Patrick; Li, Jing; Li, Ling Qiao; Kazarian, Sergei G

2014-07-01

47

Standard test method for determination of impurities in plutonium: acid dissolution, ion exchange matrix separation, and inductively coupled plasma-atomic emission spectroscopic (ICP/AES) analysis  

E-print Network

1.1 This specification covers blended uranium trioxide (UO3), U3O8, or mixtures of the two, powders that are intended for conversion into a sinterable uranium dioxide (UO2) powder by means of a direct reduction process. The UO2 powder product of the reduction process must meet the requirements of Specification C 753 and be suitable for subsequent UO2 pellet fabrication by pressing and sintering methods. This specification applies to uranium oxides with a 235U enrichment less than 5 %. 1.2 This specification includes chemical, physical, and test method requirements for uranium oxide powders as they relate to the suitability of the powder for storage, transportation, and direct reduction to UO2 powder. This specification is applicable to uranium oxide powders for such use from any source. 1.3 The scope of this specification does not comprehensively cover all provisions for preventing criticality accidents, for health and safety, or for shipping. Observance of this specification does not relieve the user of th...

American Society for Testing and Materials. Philadelphia

2003-01-01

48

Evaluation and comparison of dissolution data derived from different modified release dosage forms: an alternative method.  

PubMed

Dissolution testing is an essential requirement for the development, establishment of in vitro dissolution and in vivo performance (IVIVR), registration and quality control of solid oral dosage forms. The objective of the present study was to investigate the effect of delivery system positioning in accordance with the USP 23-recommended dissolution methods and the proposed modification on drug release from controlled release systems having different operating release mechanisms, namely, swellable floatable, swellable sticking and osmotic pump. The delivery systems were evaluated by placing each dosage form either in the dissolution vessel in accordance with the USP 23 methods or over/below a designed ring/mesh device for achieving full surface exposure to the dissolution medium for sticking or floatable systems respectively. Results indicate that the overall release profiles from the sticking and floatable systems of theophylline are sensitive to their positioning in the dissolution vessel (P<0.05). Furthermore, release of diltiazem hydrochloride from the sticking system also demonstrated sensitivity (P<0.05). In contrast, the floatable dosage form of this latter drug with the application of a helical wire sinker, or when it was placed below the ring/mesh assembly, or by allowing the dosage form to float, did not show sensitivity (P>0.05) for the overall release behavior. This was attributed to the greater solubility of diltiazem hydrochloride (50% solubility in water at 25 degreesC) in comparison to theophylline which is a sparingly soluble drug (0.85% solubility in water at 25 degreesC). Drug release from the osmotic pump appeared to be identical under the given experimental conditions (P>0.05). Statistical analysis of data was performed by comparing the t50%, t70%, t90%; mean dissolution times (MDT50%, MDT70%, MDT90%); the "difference factor, f1" and "similarity factor, f2". It is concluded that the results derived from the application of the "similarity factor, f2" are superior to the individual time points (e.g. tx%) and MDTx% values in differentiating between overall release patterns or the border line release profile differences. It also became apparent that in the case of the swellable sticking systems full surface exposure to the dissolution medium results in greater release rate. For the osmotic pump the required osmotic pressure threshold necessary for constant rate drug delivery appears to have reached independent of the hydrodynamic conditions. A successful and more accurate evaluation of dissolution data can be derived when full surface exposure is considered and this can be accomplished by dissolution method modification with the aid of the designed ring/mesh assembly. PMID:9795013

Pillay, V; Fassihi, R

1998-10-30

49

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

50

Development and validation of a discriminative dissolution test for betamethasone sodium phosphate and betamethasone dipropionate intramuscular injectable suspension.  

PubMed

The intramuscular administration of the injectable suspension betamethasone sodium phosphate (BSP) and betamethasone dipropionate (BD) has immediate therapeutic activity due to solubilized BSP and prolonged activity resulting from the slow release of BD micro-crystals. The purpose of this study was to develop and validate a dissolution method for BD in intramuscular injectable suspensions with detection by high-performance liquid chromatography (HPLC) method. Five commercial products presented a distribution of particle sizes, ranging between 7.43 and 40.25 ?m as measured by laser diffraction. It was also found that particle sizes differed between batches of the same product. The different products were tested using the paddle apparatus, with stirring speeds of 25 and 50 rpm in 300 mL of phosphate buffer; simulated body fluid, muscle fluid, and synovial fluid were used as biorelevant dissolution media at 37±0.5°C. It was verified that not only does average particle size affect the dissolution rate, but also the mode and the polydispersity index of the particles. Discriminatory power was obtained using the in vitro dissolution method with 0.1 M sodium phosphate buffer pH 7.4 containing 0.1% sodium lauryl sulfate and a stirring speed of 50 rpm. The HPLC-method is linear, precise, selective, and accurate for the quantification of BSP and BD in dissolution profile testing. This dissolution method can be utilized as a method to control the quality of these injectable suspensions. PMID:23371786

Simon, Alice; de Almeida Borges, Vinícius Raphael; Cabral, Lucio Mendes; de Sousa, Valéria Pereira

2013-03-01

51

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

52

In-situ measurement of solid phase transformations during dissolution testing  

E-print Network

In-situ Measurement of Solid Phase Transformations During Dissolution Testing Jaakko Aaltonen 1, 2 , Leena Peltonen 1 , Jouni Hirvonen 1 , Clare Strachan 2 , Jukka Rantanen 2, 3 1 Division of Pharmaceutical Technology, University of Helsinki... dissolution rate (IDR) measurements in order to achieve real-time molecular level information of solid phase behavior of APIs during dissolution testing. KEY FINDINGS The solid phase behavior cannot always be reliably derived from the IDR curve. However...

Aaltonen, J.; Strachan, C. J.; Peltonen, L.; Hirvonen, J.; Rantanen, J.

2006-10-25

53

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

Microsoft Academic Search

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

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

54

Three-Stage Sequential Statistical Dissolution Testing Rules  

Microsoft Academic Search

The U.S. Pharmacopoeia (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 USP monograph sets performance limit on dissolution in terms of a specific percentage Q that the drug product is required to be dissolved at a specified time. Japan Pharmacopoeia provides

Yi Tsong; Meiyu Shen; Vinod P. Shah

2004-01-01

55

Studies on dissolution testing of the nifedipine gastrointestinal therapeutic system. I. Description of a two-phase in vitro dissolution test  

Microsoft Academic Search

The nifedipine gastrointestinal therapeutic system (GITS) incorporates a push–pull osmotic pump to release–in zero-order fashion–a finely-divided suspension of nifedipine, which must then undergo dissolution in the GI tract before the drug can be absorbed. Classical, differential (ALZA) and flow-through type dissolution methods adequately characterize the in vitro nifedipine suspension release rate from the nifedipine GITS: however, these methods fail to

John S Grundy; Keith E Anderson; James A Rogers; Robert T Foster

1997-01-01

56

Flow-injection system for automated dissolution testing of isoniazid tablets with chemiluminescence detection  

Microsoft Academic Search

A simple and sensitive flow-injection chemiluminescence (CL) system for automated dissolution testing is described and evaluated for monitoring of dissolution profiles of isoniazid tablets. The undissolved suspended particles in the dissolved solution were eliminated via on-line filter. The novel CL system of KIO4-isoniazid was also investigated. The sampling frequency of the system was 120 h?1. The dissolution profiles of isoniazid

Baoxin Li; Zhujun Zhang; Wei Liu

2001-01-01

57

Typical variability and evaluation of sources of variability in drug dissolution testing  

Microsoft Academic Search

To investigate variability in dissolution testing an international collaborative study was performed by 29 laboratories. Glibenclamide (glyburide) tablets were used in the investigation in which multipoint dissolution profiles were established using USP paddle apparatus. In contrast to a previous report, the variability of the glibenclamide dissolution data was significantly lower. Total variances (s2) were found to range from 18.34–44.18, Between

Martin Siewert; Ludwig Weinandy; David Whiteman; Catherine Judkins

2002-01-01

58

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

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

Discrepancy among dissolution rates of commercial tables as a function of the dissolution method. Part 7: Aspirin.  

PubMed

The dissolution rate of fifteen batches of commercial aspirin tablets manufactured by five leading pharmaceutical companies was determined by closed and open dissolution systems. The most consistent results were those obtained by the USP method. Inter-batch as well as inter-brand variations were found to be more evidently detected and evaluated by adopting the USP and beaker methods, respectively. The bioavailability of these products was assessed in human subjects according to a cross-over design system. The following pharmacokinetic parameters for the drug were computed, viz., maximum excretion rate, elimination rate constant, half-life time, area under excretion rate versus time curve and total amount of drug excreted during 24 h following administration of a single oral dose. Based on the values of the correlation coefficient of the in vitro results obtained by different methods with the in vivo results, the beaker method appears to correlate best with the area under excretion rate versus time curve and total amount of drug excreted. Thus, determination of the dissolution rate of aspirin tablets by the beaker method can be considered as a reliable tool for predicting the in vivo performance of the preparation. PMID:9122273

Ammar, H A; el-Nahhas, S A; Emara, L H; Ghorab, M M; Salama, H A

1997-02-01

61

In Situ Fiber-Optic-Based Spectrophotometric Measurement for USP Dissolution Tests  

Microsoft Academic Search

A fiber-optic (FO) probe-based dissolution test system has been developed for the USP dissolution and extended-release tests for solid dosage forms. The system uses dip-type UV transflectance fiber-optic probes coupled to separate miniature photodiode array (PDA) spectrophotometers to measure the amount of drug released in real time and is applicable to the analysis of both immediate- and controlled-release formulations. The

Kevin Bynum; Kurt Roinestad; Abe Kassis; John Pocreva

62

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

63

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

64

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

Microsoft Academic Search

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

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

2002-01-01

65

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

E-print Network

dissolution of the tests. We attribute the absence of selective dissolution to the banded distribution of Mg. sacculifer supports these observations. Simple modelling of G. sacculifer test dissolution indicates in bulk test Mg/Ca composition has been documented with progressive test dissolution in deep-sea sediment

66

Studies on dissolution testing of the nifedipine gastrointestinal therapeutic system. II. Improved in vitro-in vivo correlation using a two-phase dissolution test  

Microsoft Academic Search

The nifedipine gastrointestinal therapeutic system (GITS) produces relatively linear fractional absorption-time plots between 6 and 24 h and about 70% of the available dose is absorbed within 24 h in human beings. However, conventional single-phase in vitro dissolution tests with the GITS demonstrate pseudo zero-order release of nifedipine suspension between about 2 to 20 h and ?90% of the labeled

John S Grundy; Keith E Anderson; James A Rogers; Robert T Foster

1997-01-01

67

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

PubMed

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

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

2008-08-01

68

Dissolution enhancement of gliclazide using in situ micronization by solvent change method  

Microsoft Academic Search

Gliclazide (GL) is a second-generation sulphonylurea, widely used for the treatment of non-insulin dependent diabetes mellitus. The low water-solubility of GL leads to a low dissolution rate and variable bioavailability. The aim of this study was to enhance the dissolution rate of GL by the preparation of micron-sized particles using a solvent change method. The in situ micronization process was

J. Varshosaz; R. Talari; S. A. Mostafavi; A. Nokhodchi

2008-01-01

69

Recent results from NNWSI [Nevada Nuclear Waste Storage Investigations] spent fuel leaching\\/dissolution tests  

Microsoft Academic Search

The Nevada Nuclear Waste Storage Investigations (NNWSI) Project is studying dissolution and radionuclide release behavior of spent nuclear fuel in Nevada Test Site groundwater. Results from two-year extended testing of pressurized water reactor (PWR) spent fuel at 25°C in unsealed silica vessels are discussed. These results are compared to initial results from testing in sealed stainless steel vessels at 25°C

1987-01-01

70

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

71

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

PubMed

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

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

2012-02-01

72

Dissolution testing of a metallic waste form in chloride brine  

SciTech Connect

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

Dawn E Janney

2006-11-01

73

Statistical method for evaluation of dissolution stability in the formulation development of solid dosage forms: tablets of amonafide.  

PubMed

A statistical method for the evaluation of the dissolution stability results and for selecting the most stable formulation within a solid dosage form development is discussed. Three types of tablets of an antineoplastic drug, amonafide, stored at a relative humidities (RH), 45% and 75%, were used. The drug release from tablets was tested before and after storage. The experimental data were statistically fitted to empirical model equations. Furthermore, the best mathematical fit was the statistical comparison of the residuals. From the selected model equation, time-dependent dissolution (Q45 and DE45) and dissolved quantity-dependent parameters (t70, t100 and MDT) were calculated. A useful parameter to present and evaluate the results obtained in comparative stability studies was defined: the Modification Factor (MF). It allowed the selection of the most stable formulation in the easiest and fastest way: the most stable formulation should present the smallest modification of the studied characteristics, in other words, the smallest MF value. In this way, tablets II (manufactured by wet granulation and with Emcompress as main excipient) showed the greater dissolution stability of the three types of tablets studied. Amonafide tablets must be packaged in impermeable containers, since the environmental relative humidity strongly modifies their dissolution characteristics. PMID:15296092

Gil-Alegre, M E; Bernabeu, J A; Camacho, M A; Torres-Suarez, A I

2004-07-01

74

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

Microsoft Academic Search

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

Erna Swanepoel; Wilna Liebenberg; Melgardt M. de Villiers

2003-01-01

75

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

76

Development and Characterization of Solid Dispersion for Dissolution Improvement of Furosemide by Cogrinding Method  

PubMed Central

Purpose: The purpose of this study was to prepare and characterize solid dispersion formulation of furosemide to enhance dissolution rate. Methods: Solid dispersions with different drug: carrier ratios were prepared by cogrinding method using crospovidone and microcrystalline cellulose as carrier. The physical state and interactions between the drug and carrier were characterized by Fourier transform infrared spectroscopic (FT-IR) and X ray diffraction (XRD). Results: Solid dispersions (especially with drug: Carrier ratio of 1:2) showed a higher dissolution rate than their respective physical mixture and pure furosemide. Dissolution rate in pH 5.8 was also higher than pH 1.2. The XRD analysis showed that crystalline form was changed to the amorphous state in the solid dispersions. FT-IR analysis did not show any physicochemical interactions in the solid dispersion formulations. Release kinetic of formulations were fitted best to the Weibull and Wagner log probability (linear kinetic) as well as suggested 2 and Gompertz (non-linear kinetic) models. Conclusion: The dissolution properties of furosemide were improved with the use of hydrophilic carriers in solid dispersions due to change in the crystalline form of the drug and more intimate contact between drug and carriers which was dependent on the type and ratio of carrier as well as dissolution medium pH. PMID:25436197

Siahi-Shadbad, Mohammad Reza; Ghanbarzadeh, Saeed; Barzegar-Jalali, Mohammad; Valizadeh, Hadi; Taherpoor, Alireza; Mohammadi, Ghobad; Barzegar-Jalali, Azim; Adibkia, Khosro

2014-01-01

77

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

Microsoft Academic Search

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

Jonas Johansson; Michael Cauchi; Mats Sundgren

2002-01-01

78

Method for dissolution and stabilization of silica-rich fibers  

DOEpatents

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, Carol M. (Aiken, SC)

1997-01-01

79

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

PubMed

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

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

2003-02-01

80

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

81

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

Microsoft Academic Search

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

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

82

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

83

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

84

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

NASA Astrophysics Data System (ADS)

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

Connelly, J. N.

2006-04-01

85

A numerical simulation method for dissolution in porous and fractured media  

NASA Astrophysics Data System (ADS)

We describe an algorithm for simulating reactive flows in porous media, in which the pore space is mapped explicitly. Chemical reactions at the solid-fluid boundaries lead to dissolution (or precipitation), which makes it necessary to track the movement of the solid-fluid interface during the course of the simulation. We have developed a robust algorithm for constructing a piecewise continuous ( C1) surface, which enables a rapid remapping of the surface to the grid lines. The key components of the physics are the Navier-Stokes equations for fluid flow in the pore space, the convection-diffusion equation to describe the transport of chemical species, and rate equations to model the chemical kinetics at the solid surfaces. A lattice-Boltzmann model was used to simulate fluid flow in the pore space, with linear interpolation at the solid boundaries. A finite-difference scheme for the concentration field was developed, taking derivatives along the direction of the local fluid velocity. When the flow is not aligned with the grid this leads to much more accurate convective fluxes and surface concentrations than a standard Cartesian template. A robust algorithm for the surface reaction rates has been implemented, avoiding instabilities when the surface is close to a grid point. We report numerical tests of different aspects of the algorithm and assess the overall convergence of the method.

Yu, D.; Ladd, A. J. C.

2010-09-01

86

The thermodynamics and kinetics of uranophane dissolution in bicarbonate test solutions  

Microsoft Academic Search

The thermodynamic and kinetic properties of a synthetic uranophane (Ca(H3O)2(UO2)2(SiO4)2 · 3H2O) have been determined from dissolution experiments in test solutions of different bicarbonate concentrations at 25°C. The experiments were performed using batch and continuously stirred tank flow-through reactors. From the experimental data obtained with the batch reactor the solubility constant for the reaction: Ca(H3O)2(UO2)2(SiO4)2 · 3H2O + 6H3O+ ?

Isabel Pérez; Ignasi Casas; Maria Mart??n; Jordi Bruno

2000-01-01

87

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

88

Comparative Impact of Stirring and Shearing in Drug Dissolution Testing with USP Paddle and Crescent-Shaped Spindles  

Microsoft Academic Search

A new crescent-shaped spindle has been proposed to address artefacts found with the USP Paddle spindle. Because of improved stirring and mixing environment within dissolution vessels resulting in improved product-medium interactions, the crescent-shaped spindle provides a more appropriate dissolution test. Diltiazem immediate- (IR) and extended-release (ER) tablets and capsules were used as model drug products to demonstrate that the appropriate

Saeed A. Qureshi

89

Missing molluscs: Field testing taphonomic loss in the Mesozoic through early large-scale aragonite dissolution  

NASA Astrophysics Data System (ADS)

As a field test for Cherns and Wright's previously published hypothesis based on Paleozoic faunas—that the paucity of certain molluscan groups in the fossil record may be largely a taphonomic, not ecologic, effect—a typical Mesozoic molluscan-dominated fauna is compared with its early-silicified (lagerstätten) equivalent from a similar depositional setting. A Lower Jurassic offshore carbonate ramp facies in South Wales comprises alternating thin limestones and organic-rich shales; the former are largely diagenetic and carry marine isotopic signatures. Their typical fauna is mainly well preserved, calcitic and bimineralic (calcite + aragonite), epifaunal and semiinfaunal bivalves. Evidence of aragonitic shells is normally restricted to molds, common in inner ramp settings in high-energy skeletal grainstones, but mostly poorly preserved and restricted to deep-burrowing bivalves in offshore deposits. However, locally, early silicification in offshore facies has preserved much more diverse faunas with abundant, formerly aragonitic, molluscs, including many more infaunal burrowers. It appears that major aragonite dissolution normally distorted both apparent diversity (65% decrease in bivalve diversity) and the trophic structure of the offshore facies, providing aragonite that probably sourced the diagenetic carbonates. We suggest that aragonitic shells were selectively dissolved in the upper sediment column in lower-energy settings, where high organic contents favored microbial decay and acidity; such early dissolution was absent from the higher-energy facies that originally had low organic contents. Taphonomic loss through early skeletal aragonite dissolution was an equally important process in Mesozoic offshore shelf environments, and although still leaving depleted molluscan-dominated faunas, resulted in a massive distortion of diversity.

Wright, Paul; Cherns, Lesley; Hodges, Peter

2003-03-01

90

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

91

Extraction and dissolution of starch from rice and sorghum grains for accurate structural analysis  

Microsoft Academic Search

A complete dissolution without degradation and that removes non-starch components is important for accurate characterisation of starch molecular structure. Current milling and dissolution methods have limitations including incomplete dissolution and molecular degradation. An improved multi-step extraction\\/dissolution method was devised and tested, involving cryo-grinding, protease pre-treatment, dissolution in dimethyl sulfoxide solution containing 0.5% (w\\/w) LiBr (DMSO\\/LiBr) at 80°C, centrifugation, ethanol precipitation,

Z. A. Syahariza; Enpeng Li; Jovin Hasjim

2010-01-01

92

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

93

Predicting the gastrointestinal behaviour of modified-release products: Utility of a novel dynamic dissolution test apparatus involving the use of bicarbonate buffers.  

PubMed

The establishment of physiologically relevant in vitro-in vivo correlations (IV-IVCs) is key for any biorelevant dissolution test. Historically, bicarbonate buffers have produced better correlations than compendial phosphate buffered media, though such tests are usually performed at a constant pH experiment, overlooking the notion that the pH of the luminal fluids is variable and fluctuating. In this work, we have devised a dynamic dissolution test method employing a physiological bicarbonate buffer under pH conditions of the proximal gut in order to assess the dissolution behaviour of various enteric polymer-coated (gastro-resistant) prednisolone tablets. The pH of the media is modulated and controlled by an Auto pH System™ which exploits the physiological equilibria between [H2CO3] and [HCO3(-)], to match it to the aboral change in pH with transit of the dosage form through the proximal small intestine (from pH 5.6 up to 6.8). The lag time values for an accelerated release and standard EUDRAGIT(®) L30D-55 coated formulation (25min and 60min, respectively) were close to the previously reported initial tablet disintegration time data obtained in-vivo by ?-scintigraphy (28min and 66min, respectively). Dissolution of alternative delayed release coated products was also better discriminated in the dynamic buffer system. These data confirm the dynamic dissolution system provides a robust and reliable platform to predict the in vivo fate of oral products in a laboratory setting. PMID:25195730

Merchant, Hamid A; Goyanes, Alvaro; Parashar, Narendra; Basit, Abdul W

2014-11-20

94

Electrostatic test methods compared  

Microsoft Academic Search

This paper demonstrates that electrostatic materials can be evaluated and ranked from highest to lowest in triboelectric generating capacity, and that the ranking is a function of the material, and not a function of the rubbing material. The test methods used were: (1) the NASA triboelectric tester; (2) the modified Shirley Method 18 test; and (3) the JCI ad-hoc tribocharging

R. Gompf; P. Holdstock; J. Chubb

1999-01-01

95

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

96

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

97

Clinopyroxene dissolution in basaltic melt Yang Chen *, Youxue Zhang  

E-print Network

dissolution. The models for clinopyroxene and olivine dissolution are tested against literature experimentsClinopyroxene dissolution in basaltic melt Yang Chen *, Youxue Zhang Department of Geological diffusive and convective clinopyroxene dissolution in silicate melts, diffusive clinopyroxene dissolution

Zhang, Youxue

98

Modern Methods of Testing  

NASA Technical Reports Server (NTRS)

After a brief survey of the commonly used single-value test methods, the importance of the determination of the incipient knock for the octane number is discussed and improvements suggested for the knock testing in the CFR engine. The DVL supercharge test method with its superiority of direct determination of fuel knock in each single cylinder of an airplane engine without involving structural changes, is described and the advantages of a multiple-value method enumerated. A diagrammatic presentation of the knock characteristics is presented.

Seeber, F

1939-01-01

99

Choice of rotation speed (rpm) for bio-relevant drug dissolution testing using a crescent-shaped spindle  

Microsoft Academic Search

Recently a new crescent-shaped spindle has been proposed to address the issues related to poor hydrodynamics of the USP paddle apparatus and its associated artifacts of high variability and lack of bio-relevant results. For improved comparison of drug dissolution characterization, it is highly desirable to conduct testing using common experimental conditions such as spindle rotation speed. A study was conducted

Saeed A. Qureshi

2004-01-01

100

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

101

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

PubMed

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

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

2013-09-01

102

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

Microsoft Academic Search

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

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

2008-01-01

103

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

104

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

105

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

106

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

SciTech Connect

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

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

1998-04-01

107

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

108

Evaluation of paracetamol suppositories by a pharmacopoeial dissolution test--comments on methodology.  

PubMed

Ph.Eur. and BP have introduced a dissolution apparatus for suppositories. Suitability of the apparatus for quality control of paracetamol suppositories was evaluated and the effect of experimental conditions on dissolution profiles was studied. Paracetamol suppositories containing 80-500 mg of the drug, on fatty base, were obtained from four manufacturers (A, B, C, D). The diffusion cell was modified by incorporation of an in-built thermoprobe and large difference (up to 1.7 degrees C) between temperature in the water-bath and in the dissolution chamber was observed. This effect was avoided by increasing the length of tubing immersed in the thermostat at the inlet of the cell. The most reproducible results were observed for A and C suppositories, however from suppository C the total dose of paracetamol was released after 3.5-4.5 h while the release from suppository A was slow with only 40-87% of the total dose liberated during 6 h. Suppositories B did not melt at 37 degrees C and less than 5% of the drug was released. Fast release was observed after melting when the temperature was elevated to 39.5 degrees C. The results demonstrate clearly that essentially complete melting of a suppository in the dissolution chamber is required for an appropriate dissolution of paracetamol in vitro. Disintegration time, softening time, drop point and particle size of the suspended drug were measured and the relevance of these parameters for dissolution behaviour of the preparations was discussed. PMID:11522493

Janicki, S; Sznitowska, M; Zebrowska, W; Gabiga, H; Kupiec, M

2001-09-01

109

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

110

Continuous wavelet and derivative transforms for the simultaneous quantitative analysis and dissolution test of levodopa–benserazide tablets  

Microsoft Academic Search

Simultaneous analyses and dissolution tests of levodopa–benserazide tablets were carried out by continuous wavelet transform (CWT) and classic derivative spectrophotometry (DS) without using any chemical separation step. The developed two spectrophotometric resolutions are based on the transformation of the original UV spectra. The original absorption spectra of levodopa and benserazide in the concentration range of 1–80?g\\/mL and 5–240?g\\/mL in USP

Erdal Dinç; Süha Kaya; Tanver Doganay; Dumitru Baleanu

2007-01-01

111

Predicting in vivo absorption behavior of oral modified release dosage forms containing pH-dependent poorly soluble drugs using a novel pH-adjusted biphasic in vitro dissolution test  

Microsoft Academic Search

The focus of in vitro dissolution testing during early development of modified release (MR) formulations is to provide predictive estimates of drug release in respect to in vivo performance of a drug product. However, there are enormous challenges in MR drug development to establish proper dissolution conditions for a predictive test.To overcome limitations of dissolution testing at constant pH, a

Ulrich Heigoldt; Florian Sommer; Rolf Daniels; Karl-Gerhard Wagner

2010-01-01

112

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

113

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

114

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

Microsoft Academic Search

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)â⁻ through treatment with heated NaOH

Calvin H. Delegard; V. P. Shilov; A. M. Fedoseev; NA Budantseva; M V. Nikonov; AYu Garnov; IA Charushnikova; LN Astafurova; T S. Lapitskaya; V I. Makarenkov

1999-01-01

115

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

116

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. PMID:24062966

Nawaz, Md. Saddam

2013-01-01

117

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

118

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

119

Modulation of particle size and molecular interactions by sonoprecipitation method for enhancing dissolution rate of poorly water-soluble drug.  

PubMed

Aim of present work was to originally elucidate the roles of ultrasonication method for modulating the size and molecular interactions in controlling release of poorly water-soluble drug. Curcumin was chosen as a model drug. Three types of polymers were investigated as carriers for preparation of polymeric nanoparticles under various ultrasonication conditions and polymer-drug ratios. Changes in drug crystallinity, particle size, and molecular interactions which would be factors enhancing drug dissolution rate were evaluated. Amorphous form of curcumin, size reduction of nanoparticles and interaction between drug and polymer in formulations were attributed to improved drug dissolution rate. Particle size was strongly affected by polymer type, polymer-drug ratio and ultrasonication conditions. Interestingly, control of those factors caused differences in molecular interactions of the hydroxyl groups and then, highly affected particle size of the nanoparticles. It was obvious that there was a reciprocal influence between the drug-polymer interactions and particle size of the nanoparticles. This relation could be modulated by polymers and ultrasonication processes for enhancing drug dissolution rate. PMID:25500098

Tran, Thao Truong-Dinh; Tran, Kiet Anh; Tran, Phuong Ha-Lien

2015-05-01

120

Novel Biodegradable Polylactide\\/poly(ethylene glycol) Micelles Prepared by Direct Dissolution Method for Controlled Delivery of Anticancer Drugs  

Microsoft Academic Search

Purpose  The aim of this study is to develop novel polylactide\\/poly(ethylene glycol) (PLA\\/PEG) micelles as carrier of hydrophobic drug\\u000a (paclitaxel) by direct dissolution method without using any organic solvents. The in vitro and in vivo release properties were studied in comparison with micelles prepared by dialysis.\\u000a \\u000a \\u000a \\u000a Methods  Drug encapsulation efficiency (EE) and loading content (LC) of the micelles were evaluated by high-performance

Liu Yang; Xiaohan Wu; Feng Liu; Yourong Duan; Suming Li

2009-01-01

121

Physical and dissolution characterization of cilostazol solid dispersions prepared by hot melt granulation (HMG) and thermal adhesion granulation (TAG) methods.  

PubMed

A growing number of poorly water-soluble drug have been discovered, but the poor bioavailability is a critical problem. In this study, physical properties and dissolution profiles of cilostazol solid dispersions prepared by hydrophilic/lipophilic excipients (Kollidon(®) VA64, tocopheryl polyethylene glycol succinate (TPGS), vitamine E) with hot-melt and thermal adhesion granulation (TAG) method to adsorb Fujicalin(®) and Microcel(®) were characterized. Results demonstrate the angle of repose in formulations with Fujicalin(®) was improved than those with Microcel(®), but the difference disappeared when more TPGS or vitamin E was added. Compared the formulation made by hot-melt and TAG method, both improved flowability. The hardness decreased with the increased amount of TPGS and vitamin E. The formulations with Microcel(®) had lower hardness than those with Fujicalin(®), because Microcel(®) has weaker adsorption ability and cannot afford much TPGS and vitamin E, leading to lower hardness. Furthermore, the solubility was almost three-fold higher than that of Pletaal(®) (7.68 ± 0.20 ?g/mL) in compositions containing TPGS and vitamin E made by hot-melt or TAG method, in which a controlled drug release pattern was demonstrated. There is no significant difference on dissolution profile between hot-melt and TAG method. However, the procedure of TAG is easier, indicating its potential pharmaceutical use. PMID:25089508

Chen, Ying-Chen; Ho, Hsiu-O; Chiou, Jiun-Da; Sheu, Ming-Thau

2014-10-01

122

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. PMID:23118538

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

123

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

124

[Test method for 6 phthalates in polyvinyl chloride].  

PubMed

A test method for 6 phthalates, bis(2-ethylhexyl)phthalate, dibutyl phthalate, benzyl butyl phthalate, diisononyl phthalate, diisodecyl phthalate and di-n-octyl phthalate, in polyvinyl chloride (PVC) was developed. GC/MS was used in the SIM mode for the separation and detection of phthalates. For preparation of the test solution, the extraction method with acetone-hexane mixture (3 : 7) and the dissolution method with tetrahydrofuran and ethanol were compared and it was confirmed that each method gave good recoveries. Dilution of the test solution was effective to reduce the influence of PVC. In a collaborative study with nine laboratories, the intra-laboratory variations showed good repeatability, but the measurements at some laboratories deviated widely. It appears that this method is unsuitable for the judgment of acceptability, but it may be suitable for the determination of phthalate content in PVC products. PMID:22200751

Abe, Yutaka; Mutsuga, Motoh; Hirahara, Yoshichika; Kawamura, Yoko

2011-01-01

125

Developing Discriminatory Drug Dissolution Tests and Profiles: Some Thoughts for Consideration on the Concept and Its Interpretation  

Microsoft Academic Search

Drug dissolution profiles are increasingly used to evaluate drug release characteristics of pharmaceutical products. Discrimi- natory dissolution profiles are highly desirable for differentiating between products having differences in pharmaceutical attributes (formulation and\\/or manufacturing processes differences) that may reflect corresponding differences in vivo. Commonly in the literature,differences in the profiles based only on pharmaceutical attributes have also been described as discriminatory.

Saeed A. Qureshi

126

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

127

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

128

Coherent anti-Stokes Raman Scattering (CARS) Microscopy Visualizes Pharmaceutical Tablets During Dissolution  

PubMed Central

Traditional pharmaceutical dissolution tests determine the amount of drug dissolved over time by measuring drug content in the dissolution medium. This method provides little direct information about what is happening on the surface of the dissolving tablet. As the tablet surface composition and structure can change during dissolution, it is essential to monitor it during dissolution testing. In this work coherent anti-Stokes Raman scattering microscopy is used to image the surface of tablets during dissolution while UV absorption spectroscopy is simultaneously providing inline analysis of dissolved drug concentration for tablets containing a 50% mixture of theophylline anhydrate and ethyl cellulose. The measurements showed that in situ CARS microscopy is capable of imaging selectively theophylline in the presence of ethyl cellulose. Additionally, the theophylline anhydrate converted to theophylline monohydrate during dissolution, with needle-shaped crystals growing on the tablet surface during dissolution. The conversion of theophylline anhydrate to monohydrate, combined with reduced exposure of the drug to the flowing dissolution medium resulted in decreased dissolution rates. Our results show that in situ CARS microscopy combined with inline UV absorption spectroscopy is capable of monitoring pharmaceutical tablet dissolution and correlating surface changes with changes in dissolution rate. PMID:25045833

Fussell, Andrew L.; Kleinebudde, Peter; Herek, Jennifer; Strachan, Clare J.; Offerhaus, Herman L.

2014-01-01

129

Coherent anti-Stokes Raman scattering (CARS) microscopy visualizes pharmaceutical tablets during dissolution.  

PubMed

Traditional pharmaceutical dissolution tests determine the amount of drug dissolved over time by measuring drug content in the dissolution medium. This method provides little direct information about what is happening on the surface of the dissolving tablet. As the tablet surface composition and structure can change during dissolution, it is essential to monitor it during dissolution testing. In this work coherent anti-Stokes Raman scattering microscopy is used to image the surface of tablets during dissolution while UV absorption spectroscopy is simultaneously providing inline analysis of dissolved drug concentration for tablets containing a 50% mixture of theophylline anhydrate and ethyl cellulose. The measurements showed that in situ CARS microscopy is capable of imaging selectively theophylline in the presence of ethyl cellulose. Additionally, the theophylline anhydrate converted to theophylline monohydrate during dissolution, with needle-shaped crystals growing on the tablet surface during dissolution. The conversion of theophylline anhydrate to monohydrate, combined with reduced exposure of the drug to the flowing dissolution medium resulted in decreased dissolution rates. Our results show that in situ CARS microscopy combined with inline UV absorption spectroscopy is capable of monitoring pharmaceutical tablet dissolution and correlating surface changes with changes in dissolution rate. PMID:25045833

Fussell, Andrew L; Kleinebudde, Peter; Herek, Jennifer; Strachan, Clare J; Offerhaus, Herman L

2014-01-01

130

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

131

Predicting in vivo absorption behavior of oral modified release dosage forms containing pH-dependent poorly soluble drugs using a novel pH-adjusted biphasic in vitro dissolution test.  

PubMed

The focus of in vitro dissolution testing during early development of modified release (MR) formulations is to provide predictive estimates of drug release in respect to in vivo performance of a drug product. However, there are enormous challenges in MR drug development to establish proper dissolution conditions for a predictive test. To overcome limitations of dissolution testing at constant pH, a modified USP apparatus 2 was developed, combining biphasic dissolution with a pH-gradient in the aqueous dissolution medium. Quasi sink conditions in the aqueous phase were introduced by the removal of dissolved active via distribution to an organic phase. Results from in vitro drug-release studies and in vivo absorption studies of four MR formulations made by different technologies comprising the pH-dependent poorly soluble drugs, dipyridamole and the investigational drug BIMT 17, indicated that dissolution testing using the biphasic approach enabled an improved forecast of the in vivo behavior and bioavailability of modified release formulations compared to conventional dissolution testing at pH 1, pH 5.5, or pH 6.8. It can be concluded that the novel pH-adjusted dissolution test might be a useful tool in early drug development to develop, select, and optimize MR prototypes of Biopharmaceutical Classification System (BCS) II compounds. PMID:20472059

Heigoldt, Ulrich; Sommer, Florian; Daniels, Rolf; Wagner, Karl-Gerhard

2010-09-01

132

Hepa filter dissolution process  

DOEpatents

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

Brewer, Ken N. (Arco, ID); Murphy, James A. (Idaho Falls, ID)

1994-01-01

133

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

134

Evaluation of in vitro dissolution profile comparison methods of sustained release tramadol hydrochloride liquisolid compact formulations with marketed sustained release tablets.  

PubMed

The aim of the present work was to prepare and evaluate sustained release liquisolid compact formulations of tramadol hydrochloride. The dissolution profile of the prepared compacts was also compared to that of a marketed preparation. Liquisolid sustained release formulations were prepared by using HPMC K4M as a sustained release agent. Precompression studies of characteristics such as flow properties were also carried out. Liquisolid compacts were evaluated by hardness, friability, and in vitro dissolution studies. Comparison of dissolution profiles was carried out by using a modelindependent, model-dependent, and statistical approach. The prepared liquisolid compacts are new dosage forms with better sustained release behavior compared to a marketed sustained formulation. The dissolution profile followed the Peppas model as "best fit" model. Two-way ANOVA results revealed a significant difference in dissolution profiles. This systematic approach to producing a formulation was found to help with analyzing the sustained release of tramadol hydrochloride. The use and evaluation of model-dependent methods is more complicated. These methods provide an acceptable model approach that indicates the true relationship between percent drug release and time variables, including statistical assumptions. PMID:22491149

Karmarkar, A B; Gonjari, I D; Hosmani, A H; Dhabale, P N

2010-02-01

135

Thermal well-test method  

DOEpatents

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

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

1985-01-01

136

Thermal well-test method  

DOEpatents

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

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

1984-02-24

137

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

138

Development and validation of a stability-indicating LC method for the determination of venlafaxine in extended-release capsules and dissolution kinetic studies.  

PubMed

A stability-indicating reversed-phase high-performance liquid chromatography method is developed and validated for the determination of venlafaxine hydrochloride (VEN) in extended-release capsules containing spherical beads and for dissolution studies. The method is carried out on a Luna C(18) column (250 mm x 4.6 mm) maintained at 35 degrees C. The mobile phase is composed of ammonium-acetate buffer 32 mM, adjusted to pH 6.8 with phosphoric acid-acetonitrile-methanol (62:30:8, v/v/v), run at a flow rate of 1.0 mL/min, and detection at 226 nm. Validation parameters such as the specificity, linearity, precision, accuracy, and robustness are evaluated, giving results within the acceptable range. In order to evaluate the best dissolution condition, the dissolution profiles are performed under different conditions, such as media (HCl, water, phosphate buffer), apparatus (I and II), and dissolution rates (50, 75, and 100 rpm). The kinetics release mechanism is evaluated by fitting different models, such as the zero order rate, first order, and Higuchi. Moreover, the proposed method is successfully applied for the assay of VEN in extended-release capsules. PMID:19835686

Bernardi, Larissa S; Oliveira, Paulo R; Murakami, Fábio S; Borgmann, Silvia H M; Arend, Marcela Z; Cardoso, Simone G

2009-10-01

139

In vitro dissolution and physicochemical characterizations of novel PVP-based solid dispersions containing valsartan prepared by a freeze-drying method.  

PubMed

Valsartan (VAL) shows poor oral bioavailability mainly as a result of its low water solubility at low pH. This study is designed to investigate the dissolution properties and physicochemical characteristics of novel PVP-based solid dispersions (SDs) containing VAL. The SDs were prepared with polyvinylpyrrolidone (PVP-K30) as a hydrophilic polymer, sodium hydroxide (NaOH) as an alkalizer, and poloxamer 188 (F68) as a surfactant, without using any organic solvents by a freeze-drying method. The dissolution study was carried out and the physicochemical properties of SDs were also characterized by using differential scanning calorimetry (DSC), fourier transform-infrared (FT-IR) spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The dissolution rates of SDs were significantly improved at pH1.2 and pH6.8 compared to that of pure drug. The results of physicochemical properties suggested that some interactions between VAL and carriers had occurred in the molecular level and the drug presented in the SDs was amorphous. It was concluded that the novel PVP-based SDs has been successfully prepared by a freeze-drying method, resulting in significant dissolution improvement of VAL. PMID:25362604

Xu, Wei-Juan; Liu, Yan; Shi, Li-Li; Cui, Jing-Hao; Cao, Qing-Ri

2014-11-01

140

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. PMID:24082345

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

2013-01-01

141

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. PMID:24300301

Pinto, Eduardo Costa; do Carmo, Flávia Almada; da Silva Honório, Thiago; da Silva Ascenção Barros, Rita de Cássia; Castro, Helena Carla Rangel; Rodrigues, Carlos Rangel; Esteves, Valéria Sant'Anna Dantas; Rocha, Helvécio Vinícius Antunes; de Sousa, Valeria Pereira; Cabral, Lucio Mendes

2012-01-01

142

30 CFR 27.31 - Testing methods.  

Code of Federal Regulations, 2011 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...

2011-07-01

143

30 CFR 27.31 - Testing methods.  

Code of Federal Regulations, 2010 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...

2010-07-01

144

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

145

30 CFR 27.31 - Testing methods.  

...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...

2014-07-01

146

30 CFR 27.31 - Testing methods.  

Code of Federal Regulations, 2012 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...

2012-07-01

147

The Development of USP Dissolution and Drug Release Standards  

Microsoft Academic Search

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

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

1990-01-01

148

Error response test system and method using test mask variable  

NASA Technical Reports Server (NTRS)

An error response test system and method with increased functionality and improved performance is provided. The error response test system provides the ability to inject errors into the application under test to test the error response of the application under test in an automated and efficient manner. The error response system injects errors into the application through a test mask variable. The test mask variable is added to the application under test. During normal operation, the test mask variable is set to allow the application under test to operate normally. During testing, the error response test system can change the test mask variable to introduce an error into the application under test. The error response system can then monitor the application under test to determine whether the application has the correct response to the error.

Gender, Thomas K. (Inventor)

2006-01-01

149

Loading control method for structural seismic test  

NASA Astrophysics Data System (ADS)

In this paper, three loading control methods of structural seismic test along with software developments and applications are introduced: (1) quasi-static test method and control software TUST; (2) multi-dimensional quasi-static test method and control software TUMT; (3) pseudodynamic test method and control software TUT, 2D and substructuring techniques. The alpha-method and PC- Newmark method were employed in TUT. All of the three tests loading control software that is based on the platform of Windows NT and Visual C++ have been put into practice in structural laboratory of Tsinghua University.

Qiu, FaWei; Pan, Peng; Li, Wenfeng; Song, Yiyan; Du, Wenbo

2002-05-01

150

Insulator Icing Test Methods and Procedure  

Microsoft Academic Search

This is a position paper prepared by the IEEE Task Force on Insulator Icing Test Methods. Test methods for evaluating flashover voltage of ceramic and nonceramic insulators under ice, snow, and cold-fog conditions are recommended. The paper describes the procedure to be followed at various stages of an evaluation test including preparation of the test object, insulator precontamination, ice, snow,

M. Farzaneh; T. Baker; K. Brown; W. A. Chisholm; C. de Tourreil; J. F. Drapeau; S. Fikke; J. M. George; E. Gnandt; T. Grisham; I. Gutman; R. Hartings; R. Kremer; G. Powell; L. Rolfseng; T. Rosek; D. L. Ruff; D. Shaffner; V. Skienicka; R. Sundararajan; J. Yu

2002-01-01

151

In vitro release testing of matrices based on starch-methyl methacrylate copolymers: effect of tablet crushing force, dissolution medium pH and stirring rate.  

PubMed

Direct-compressed matrix tablets were obtained from a variety of potato starch-methyl methacrylate copolymers(1) as sustained-release agents, using anhydrous theophylline as a model drug. The aim of this work was to investigate the influence of the copolymer type, the tablet crushing force and dissolution variables such as the pH of the dissolution medium and the agitation intensity on the in vitro drug release behaviour of such matrices. Commercial sustained-release theophylline products (Theo-Dur(®) 100mg, Theolair(®) 175 mg) were used as standards. Test formulations were compacted into tablets at three different crushing force ranges (70-80, 90-100 and 110-120 N) to examine the effect of this factor on the porous network and drug release kinetics. In vitro release experiments were conducted in a pH-changing medium (1.2-7.5) with basket rotation speeds in the range 25-100 r.p.m. to simulate the physiological conditions of the gastrointestinal tract. The release rate of theophylline was practically not affected by pH in the case of Theo-Dur(®) and HSMMA matrices. In contrast, Theolair(®) and CSMMA tablets demonstrated a biphasic drug release pattern, which appeared to be sensitive to the pH of the dissolution medium. An increase in the crushing force of the copolymer matrices was accompanied by a reduction of the matrix porosity, although the porous network depends markedly on the type of copolymer, having a strong influence on the drug release kinetics. Mathematical modelling of release data shows a Fickian diffusion or anomalous transport mechanism. Based on the similarity factor f2, FD-HSMMA, OD-CSMMA and FD-CSMMA at 90-100 N were selected for agitation studies. In general, all formulations showed an agitation speed-dependent release, with Theo-Dur(®) and FD-CSMMA matrices being the less susceptible to this factor. PMID:24333902

Ferrero, C; Jiménez-Castellanos, M R

2014-01-30

152

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

SciTech Connect

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

Hai Huang; Xiaoyi Li

2011-01-01

153

Applying Formal Methods to Software Testing  

Microsoft Academic Search

This thesis examines applying formal methods to software testing. Software testingis a critical phase of the software life-cycle which can be very effective if performedrigorously. Formal specifications offer the bases for rigorous testing practices. Notsurprisingly, the most immediate use of formal specifications in software testing isas sources of black-box test suites. However, formal specifications have more usesin software testing than

Philip Alan Stocks

1993-01-01

154

Screening methods for caloric testing.  

PubMed

In order to evaluate the screening capacity and the reliability of monothermal caloric stimulation, the caloric results obtained in 272 patients have been reviewed. The results of a complete bithermal 4-test-set are compared with the results of the hot and cold stimulation considered separately. The supposition that a complete 4-test set is necessary only if the monothermal reaction shows significant asymmetry, is tested by determining how far this would lead to a correct evaluation compared with the final results obtained by the bithermal testing. The study shows that hot as well as cold monothermal screening would result in too many false positive as well as false negative findings. A test procedure consisting of an alternating bithermal stimulation is proposed as a technique for shortening the examination time. This technique has proven to be reliable and it is also more comfortable for the patient. PMID:3496992

Norré, M E

1987-06-01

155

A new approach for measuring dissolution rates of silicate minerals by using silicon isotopes  

NASA Astrophysics Data System (ADS)

The two major problems in measuring dissolution rates under close-to-natural conditions in laboratory experiments are: (1) our inability to measure small differences in concentration between solutions with relatively high concentrations and (2) the inherent problem that the change in solution concentration is affected by both the dissolution of the primary mineral and the precipitation of secondary minerals. The present manuscript proposes and tests a novel method, "the isotope ratio method", for measuring slow dissolution rates of silicate minerals by measuring the change in the ratios between stable isotopes of silicon of a spiked solution. Based on mass balance calculations, two equations that describe the dissolution rate of a silicate mineral in a batch reactor and in a flow-through reactor at steady-state are developed. The precipitation rate of the secondary mineral may be calculated by subtracting the release rate of Si that was calculated using isotope dilution from the rate that was calculated using the proposed isotope ratio method. Numerical simulations of flow-through and batch experiments demonstrate that the "isotope ratio method" is significantly more precise than conventional methods. The analytical uncertainty for the determination of dissolution rates was found to be low for the entire range of reported field-based dissolution rates. The calculation showed that even relatively large isotopic fractionations (up to ? values of 20‰), introduce insignificant uncertainties. Preliminary flow-through experiments support the above conclusion that dissolution rate may be obtained accurately and with small uncertainty using the proposed "isotope ratio method".

Gruber, Chen; Harpaz, Liat; Zhu, Chen; Bullen, Tom D.; Ganor, Jiwchar

2013-03-01

156

[Dissolution behaviors of tablet and capsule covered with oblate or agar jelly for taking medicine easily].  

PubMed

Drugs are sometimes covered with oblate or agar jelly. It is said that the medicinal effect of drugs covered with oblate is slow, but no studies have reported results confirming this. Therefore, we examined the dissolution behavior when the drug was covered with oblate or agar jelly. Three types of commercially available formulations of benzodiazepine were used: medazepam sugarcoated tablets, prazepam uncoated tablets, and clorazepate dipotassium capsules. Dissolution tests were performed using solutions of pH 1.2 and 5.6 to simulate normal gastric juice and gastric anacidity, respectively. Drugs covered with oblate were tested by the paddle method, and those covered with agar jelly were tested using the rotating basket method. Dissolution of clorazepate capsules not covered with oblate increased by approximately 10% when the pH was adjusted from 1.2 to 5.6, while those of medazepam and prazepam tablets decreased by approximately 40-60%. In contrast, the dissolution decreased significantly at both pH values for each drug covered with oblate. Dissolution further decreased when the amount of oblate was doubled. No detectable dissolution of medazepam tablets or of clorazepate capsules occurred when the drug was covered with agar jelly. Dissolution of prazepam tablets covered with agar jelly was only about 10% at the end of the test. These results indicate that dissolution is slowed and prolonged when a drug is covered with oblate or agar jelly, permitting sustained release of the drug. But, it is necessary to improve a suitable method for the dissolution. PMID:21212625

Hayase, Nobumasa; Iwayama, Kuninori; Ohtaki, Ko-Ichi; Yamashita, Yasunori; Awaya, Toshio; Matsubara, Kazuo

2011-01-01

157

Nanotechnology versus other techniques in improving drug dissolution.  

PubMed

Many newly discovered drug molecules have low aqueous solubility, which results in low bioavailability. One way to improve their dissolution is to formulate them as nanoparticles, which have high specific surface areas, consequently increasing the dissolution rate and solubility. Nanoparticles can be produced via top-down or bottom-up methods. Top-down techniques such as wet milling and high pressure homogenisation involve reducing large particles to nano-sizes. Some pharmaceutical products made by these processes have been marketed. Bottom-up methods such as precipitation and controlled droplet evaporation form nanoparticles from molecules in solution. To minimise aggregation upon drying and promote redispersion of the nanoparticles upon reconstitution or administration, hydrophilic matrix formers are added to the formulation. However, the nanoparticles will eventually agglomerate together after dispersing in the liquid and hinders dissolution. Currently there is no pharmacopoeial method specified for nanoparticles. Amongst the current dissolution apparatus available for powders, the flow-through cell has been shown to be the most suitable. Regulatory and pharmacopoeial standards should be established in the future to standardise the dissolution testing of nanoparticles. More nanoparticle formulations of new hydrophobic drugs are expected to be developed in the future with the advancement of nanotechnology. However, the agglomeration problem is inherent and difficult to overcome. Thus the benefit of dissolution enhancement often cannot be fully realised. On the other hand, chemical strategies such as modifying the parent drug molecule to form a more soluble salt form, prodrug, or cyclodextrin complexation are well established and have been shown to be effective in enhancing dissolution. Thus the value of nanoformulations needs to be interpreted in the light of their limitations. Chemical approaches should also be considered in new product development. PMID:23651399

Kwok, Philip Chi Lip; Chan, Hak-Kim

2014-01-01

158

Tribological test methods and apparatus  

Microsoft Academic Search

Tribology is the term that has been applied since 1966 to the science of friction, wear, lubrication, and the interaction of contacting surfaces when they are displaced relative to each other. Tribology characteristically employs a broad circle of experimental methods. This circle is expanding continuously, and the methods are being improved. Even the prescientific period of development of engineering thought

I. A. Buyanovskii

1994-01-01

159

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

160

Application of phospholipid complex technique to improve the dissolution and pharmacokinetic of probucol by solvent-evaporation and co-grinding methods.  

PubMed

To enhance the aqueous solubility and thus oral bioavailability of a poorly water-soluble drug, probucol (PB), probucol-phospholipid complex (PB-PC) was formulated by solvent-evaporation or co-grinding methods. The complexes were characterized by differential scanning calorimetry (DSC), infrared spectroscopy (IR), powder X-ray diffraction (PXRD), solubility, oil-water partition coefficient and in vitro dissolution. The DSC, IR and PXRD data confirmed the formation of phospholipid complex. Furthermore, the results indicated hydrogen bond formation between PB and PC molecules play an important role in the formation of PB-PC without the formation of a new compound. The water solubility of PB in the complexes was improved from 0.005 to 17.76 or 1.65 ?g/mL (by solvent-evaporation or co-grinding methods respectively). As a result of it, the improved dissolution was shown in the prepared complexes. The PB-PC complexes by both solvent-evaporation and co-grinding methods exhibited higher peak plasma concentration (16,625.7 or 5343.3 vs. 2628.4 ng mL(-1)), increased AUC0-48 h (145,863.2 or 77,477.0 vs. 34,435.9 ng mL(-1)h) when compared with the commercial product, suggesting improved bioavailability of the drug. The study therefore suggests that the phospholipid complexes have possibilities in enhancing the therapeutic efficacy of PB which may be due to its improved aqueous solubility, dissolution behavior and thus bioavailability. PMID:25108049

Guo, Bei; Liu, Hongzhuo; Li, Yun; Zhao, Juanhang; Yang, Dan; Wang, Xianglin; Zhang, Tianhong

2014-10-20

161

Modeling and comparison of dissolution profiles.  

PubMed

Over recent years, drug release/dissolution from solid pharmaceutical dosage forms has been the subject of intense and profitable scientific developments. Whenever a new solid dosage form is developed or produced, it is necessary to ensure that drug dissolution occurs in an appropriate manner. The pharmaceutical industry and the registration authorities do focus, nowadays, on drug dissolution studies. The quantitative analysis of the values obtained in dissolution/release tests is easier when mathematical formulas that express the dissolution results as a function of some of the dosage forms characteristics are used. In some cases, these mathematic models are derived from the theoretical analysis of the occurring process. In most of the cases the theoretical concept does not exist and some empirical equations have proved to be more appropriate. Drug dissolution from solid dosage forms has been described by kinetic models in which the dissolved amount of drug (Q) is a function of the test time, t or Q=f(t). Some analytical definitions of the Q(t) function are commonly used, such as zero order, first order, Hixson-Crowell, Weibull, Higuchi, Baker-Lonsdale, Korsmeyer-Peppas and Hopfenberg models. Other release parameters, such as dissolution time (tx%), assay time (tx min), dissolution efficacy (ED), difference factor (f1), similarity factor (f2) and Rescigno index (xi1 and xi2) can be used to characterize drug dissolution/release profiles. PMID:11297896

Costa, P; Sousa Lobo, J M

2001-05-01

162

Bacterial mutagenicity assays: test methods.  

PubMed

The most widely used assays for detecting chemically induced gene mutations are those employing bacteria. The plate incorporation assay using various Salmonella typhimurium LT2 and E. coli WP2 strains is a short-term bacterial reverse mutation assay specifically designed to detect a wide range of chemical substances capable of causing DNA damage leading to gene mutations. The test is used worldwide as an initial screen to determine the mutagenic potential of new chemicals and drugs.The test uses several strains of S. typhimurium which carry different mutations in various genes of the histidine operon, and E. coli which carry the same AT base pair at the critical mutation site within the trpE gene. These mutations act as hot spots for mutagens that cause DNA damage via different mechanisms. When these auxotrophic bacterial strains are grown on a minimal media agar plates containing a trace of the required amino-acid (histidine or tryptophan), only those bacteria that revert to amino-acid independence (His(+) or Tryp(+)) will grow to form visible colonies. The number of spontaneously induced revertant colonies per plate is relatively constant. However, when a mutagen is added to the plate, the number of revertant colonies per plate is increased, usually in a dose-related manner.This chapter provides detailed procedures for performing the test in the presence and absence of a metabolic activation system (S9-mix), including advice on specific assay variations and any technical problems. PMID:22147566

Gatehouse, David

2012-01-01

163

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

164

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

165

Preparation, Physicochemical Characterization and In-vitro Dissolution Studies of Diosmin-cyclodextrin Inclusion Complexes  

PubMed Central

Diosmin, a vascular-protecting agent, is practically insoluble in water, and its oral absorption is limited by its extremely low dissolution rate. In this study, ?-cyclodextrin (?CD) and 2-hydroxypropyl-?-cyclodextrin (HP?CD) were obtained to improve the solubility and dissolution rate of diosmin. Phase solubility studies of diosmin with ?CD and HP?CD in distilled water were conducted to characterize the complexes in liquid state. The solid-state characterization of the complexes prepared with different methods was performed by fourier transform-infra red spectroscopy (FTIR), optical microscopy analyses, and differential scanning calorimetry (DSC). Dissolution studies were carried out in distilled water using US pharmacopeia dissolution rate testing equipment. The complexation of diosmin with ?CD and HP?CD both indicated an AL type of phase-solubility diagrams, and the apparent stability constants (Kc) was found to be 222.13 and 200.08 M?1, respectively. The Kc values indicated the ?CD and HP?CD showed the similar equal complexation ability with diosmin, HP?CD provided higher solubility for diosmin due to its higher water solubility. The dissolution studies suggest that the inclusion complexes provide higher dissolution rate compared with the physical mixtures and the drug alone. Furthermore, the inclusion complex prepared by freeze drying method presented higher dissolution rate than kneading method.

Ai, Fengwei; Ma, Yingli; Wang, Jiayu; Li, Yanfeng

2014-01-01

166

Preparation, Physicochemical Characterization and I n - vitro Dissolution Studies of Diosmin-cyclodextrin Inclusion Complexes.  

PubMed

Diosmin, a vascular-protecting agent, is practically insoluble in water, and its oral absorption is limited by its extremely low dissolution rate. In this study, ?-cyclodextrin (?CD) and 2-hydroxypropyl-?-cyclodextrin (HP?CD) were obtained to improve the solubility and dissolution rate of diosmin. Phase solubility studies of diosmin with ?CD and HP?CD in distilled water were conducted to characterize the complexes in liquid state. The solid-state characterization of the complexes prepared with different methods was performed by fourier transform-infra red spectroscopy (FTIR), optical microscopy analyses, and differential scanning calorimetry (DSC). Dissolution studies were carried out in distilled water using US pharmacopeia dissolution rate testing equipment. The complexation of diosmin with ?CD and HP?CD both indicated an AL type of phase-solubility diagrams, and the apparent stability constants (Kc) was found to be 222.13 and 200.08 M(-1), respectively. The Kc values indicated the ?CD and HP?CD showed the similar equal complexation ability with diosmin, HP?CD provided higher solubility for diosmin due to its higher water solubility. The dissolution studies suggest that the inclusion complexes provide higher dissolution rate compared with the physical mixtures and the drug alone. Furthermore, the inclusion complex prepared by freeze drying method presented higher dissolution rate than kneading method. PMID:25587299

Ai, Fengwei; Ma, Yingli; Wang, Jiayu; Li, Yanfeng

2014-01-01

167

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

168

Test Method of Pneumatic Cylinder's life  

Microsoft Academic Search

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

Ma Jungong; ONEYAMA Naotake

2007-01-01

169

Evaluation of a three compartment in vitro gastrointestinal simulator dissolution apparatus to predict in vivo dissolution.  

PubMed

In vitro dissolution tests are performed for new formulations to evaluate in vivo performance, which is affected by the change of gastrointestinal (GI) physiology, in the GI tract. Thus, those environmental changes should be introduced to an in vitro dissolution test. Many studies have successfully shown the improvement of in vitro-in vivo correlations (IVIVC) by introducing those physiological changes into dissolution tests. The gastrointestinal simulator (GIS), a multicompartment in vitro dissolution apparatus, was developed to evaluate in vivo drug dissolution. A gastric-emptying rate along with transit rate are key factors to evaluate in vivo drug dissolution and, hence, drug absorption. Dissolution tests with the GIS were performed with Biopharmaceutical Classification System class I drugs at five different gastric-emptying rates in the fasted state. Computational models were used to determine in vivo gastric-emptying time for propranolol and metoprolol based on the GIS dissolution results. Those were compared with published clinical data to determine the gastric half-emptying time. In conclusion, the GIS is a practical tool to assess dissolution properties and can improve IVIVC. PMID:25251982

Takeuchi, Susumu; Tsume, Yasuhiro; Amidon, Gregory E; Amidon, Gordon L

2014-11-01

170

Absorbing Software Testing into the Scrum Method  

NASA Astrophysics Data System (ADS)

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

Tuomikoski, Janne; Tervonen, Ilkka

171

[Development and application of six-channel fiber optic sensing drug dissolution monitor].  

PubMed

The drug dissolution test is an important examination of drug testing, which plays a very important role in the drug quality assessment. Automation and proceduring monitoring of drug dissolution can be implemented by the optical fiber sensing technology. Two modes of detection of UV-Vis absorption and fluorescence quenching were established by software implementation, with xenon lamp, deuterium lamp or halogen tungsten lamp as fluorescence, UV and visible light source, branch Y type optical fiber as light path transmission medium, UV-Vis probe and fluorescence molecular probe as light response devices, and CCD as detector. Optical fiber sensing drug dissolution monitor not only solves the current problems of time-consuming, and sampling of off-line analysis, but also provides real-time information of drug dissolution process. Thus, our study may provide a better evaluation method for the drug quality control. PMID:25532369

Yao, Jun; Shen, Jing; Li, Li; Li, Xin-Xia; Chen, Jian

2014-09-01

172

Diffusion with dissolution and precipitation in a porous media  

E-print Network

. Quelques tests numériques sont ensuite montrés. KEYWORDS: diffusion, dissolution­precipitation, porousDiffusion with dissolution and precipitation in a porous media approximation by a finite volume and dissolution­ precipitation equations with non homogeneous Dirichlet boundary conditions. The approximate

Herbin, Raphaèle

173

Simulation of surface dynamics during dissolution as a function of the surface orientation: Implications for non-constant dissolution rates  

NASA Astrophysics Data System (ADS)

An important problem in geochemistry is the understanding of how changes occurring on a surface during dissolution affect the variability of measured dissolution rates. In this study a new approach to study the effect of surface dynamics on dissolution rates is tested by coupling experimental data with a numerical model that simulates the retreat of surface profiles during dissolution. We present specific results from the simulation of dissolution of fluorite surfaces. The equations that determine the retreat of a surface are based on experimentally obtained equations that relate the retreat rate of a surface to a single variable, the crystallographic orientation of the surface. Our results show that depending on the starting orientation, different types of topography are developed, similar to those observed experimentally. During the initial dissolution phase, changes of topography are rapid and associated with fast dissolution rates. The progressively slower dissolution rates are coupled with the development of surface segments with orientations that dissolve at a slower rate. Consequently, the overall retreat rate of a profile decreases during the simulation, and tends to a near-constant value. The results show a close relationship between dissolution rates, surface orientation and surface dynamics, which suggests that the dissolution rate of a specific mineral phase is not constant but varies with dissolution time and surface structure. This variability needs to be considered in the evaluation of experimentally derived dissolution rates, future dissolution experiments, and predictive kinetic models of dissolution.

Godinho, J. R. A.; Piazolo, S.; Evans, L.

2014-12-01

174

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

175

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

176

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

177

Standard practice for preparation and dissolution of plutonium materials for analysis  

E-print Network

1.1 This practice is a compilation of dissolution techniques for plutonium materials that are applicable to the test methods used for characterizing these materials. Dissolution treatments for the major plutonium materials assayed for plutonium or analyzed for other components are listed. Aliquants of the dissolved samples are dispensed on a weight basis when one of the analyses must be highly reliable, such as plutonium assay; otherwise they are dispensed on a volume basis. 1.2 The treatments, in order of presentation, are as follows: Procedure Title Section Dissolution of Plutonium Metal with Hydrochloric Acid 9.1 Dissolution of Plutonium Metal with Sulfuric Acid 9.2 Dissolution of Plutonium Oxide and Uranium-Plutonium Mixed Oxide by the Sealed-Reflux Technique 9.3 Dissolution of Plutonium Oxide and Uranium-Plutonium Mixed Oxides by Sodium Bisulfate Fusion 9.4 Dissolution of Uranium-Plutonium Mixed Oxides and Low-Fired Plutonium Oxide in Beakers 9.5 1.3 The values stated in SI units are to be re...

American Society for Testing and Materials. Philadelphia

2008-01-01

178

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

179

Dissolution enthalpies of cellulose in ionic liquids.  

PubMed

In this work, interactions between cellulose and ionic liquids were studied calorimetrically and by optical microscopy. Two novel ionic liquids (1,5-Diazabicyclo[4.3.0]non-5-enium propionate and N-methyl-1,5-diazabicyclo[4.3.0]non-5-enium dimethyl phosphate) and 1-ethyl-3-methylimidazolium acetate-water mixtures were used as solvents. Optical microscopy served in finding the extent of dissolution and identifying the dissolution pattern of the cellulose sample. Calorimetric studies identified a peak relating to dissolution of cellulose in solvent. The transition did, however, not indicate complete dissolution, but rather dissolution inside fibre or fibrils. This method was used to study differences between four cellulose samples with different pretreatment or origins. PMID:25256460

Parviainen, Helena; Parviainen, Arno; Virtanen, Tommi; Kilpeläinen, Ilkka; Ahvenainen, Patrik; Serimaa, Ritva; Grönqvist, Stina; Maloney, Thaddeus; Maunu, Sirkka Liisa

2014-11-26

180

Chlorhexidine gel associated with papain in pulp tissue dissolution  

PubMed Central

Objectives This study aimed to evaluate the capacity of 2% chlorhexidine gel associated with 8% papain gel in comparison with 5.25% sodium hypochlorite in bovine pulp tissue dissolution. Materials and Methods Ninety bovine pulps of standardized sizes were used and fragmented into 5-mm sizes. The fragments were removed from the root middle third region. They were divided into 6 experimental groups (n = 15), 1) 8% papain; 2) 2% chlorhexidine; 3) 2% chlorhexidine associated with 8% papain; 4) 0.9% saline solution; 5) 2.5% sodium hypochlorite; and 6) 5.25% sodium hypochlorite. The pulp fragments were weighed and put into immobile test tubes for dissolution for time intervals of 30, 60, 90, and 120 min. Results The 5.25% sodium hypochlorite had greater dissolution potential than the pure papain, and when associated with chlorhexidine, both promoted greater dissolution than did the saline solution and 2% chlorhexidine groups (p < 0.05). The 2.5% sodium hypochlorite promoted dissolution to a lesser extent than the groups with papain within a period of 30 min (p < 0.05), but, was comparable to the saline solution and chlorhexidine. After 120 min, the 2.5% and 5.25% sodium hypochlorite promoted dissolution of 100% of the pulp fragments, and papain, 61%, while chlorhexidine associated with papain and chlorhexidine alone dissolved only 55% and 3%, respectively. Conclusions The 8% papain in gel, both alone and in association with chlorhexidine, was able to dissolve bovine pulp tissue, but to a lesser extent than did 5.25% sodium hypochlorite. PMID:24303355

Couto De Oliveira, Gabriel; Ferraz, Caio Souza; Andrade Júnior, Carlos Vieira

2013-01-01

181

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

182

Dissolution properties and physical characterization of telmisartan-chitosan solid dispersions prepared by mechanochemical activation.  

PubMed

Solid dispersion systems of telmisartan (a poorly water-soluble antihypertension drug) with biopolymer carrier chitosan have been investigated in this study. The mechanism of solubilization of chitosan for drug has been studied. In addition, the influence of several factors was carefully examined, including the preparation methods, the drug/carrier weight ratios, and the milling time. Drug dissolution and physical characterization of different binary systems were studied by in vitro dissolution test, particle size distribution, Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffractometry, and scanning electron microscopy. The results presented that the weak basic property of chitosan appeared as the main driving force for the drug dissolution enhancement. Other effects such as decreased drug crystallinity and size played a positive contributory role. Among the preparation methods, cogrinding was the best method showing strong drug amorphization, reduced particle size, and enhanced dissolution. The drug dissolution markedly improved with increasing the amount of chitosan in solid mixtures. As a result, a significant effect of chitosan increasing telmisartan dissolution has been demonstrated, and cogrinding in a roll ball mill was the best way to prepare solid dispersions, which had high degree of uniformity in drug content and had a practical application in manufacturing. PMID:23430728

Zhong, Lin; Zhu, Xingyi; Luo, Xiaofang; Su, Weike

2013-06-01

183

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

184

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

185

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

SciTech Connect

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, {sup 1}H-NMR, {sup 13}C-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, E-mail: lucy205@yahoo.com [Department of Chemistry, Faculty of Mathematics and Natural Science, Universitas Tanjungpura, Jl. A.Yani, 73 Pontianak 78124 (Indonesia); Wahyuningrum, Deana, E-mail: deana@chem.itb.ac.id; Nurrachman, Zeily, E-mail: deana@chem.itb.ac.id; Natalia, Dessy, E-mail: deana@chem.itb.ac.id [Department of Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132 (Indonesia)

2014-03-24

186

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

2005-07-01

187

Multiple-time-point dissolution specifications for a sampling acceptance plan  

Microsoft Academic Search

In dissolution testing, multiple dissolution measurements at specific time points are used to obtain the dissolution characteristics for most extended- release and some immediate-release drug products. This paper presents a general procedure for defining specifications by a multivariate confidence region or by simultaneous confidence limits on the dissolution values of individual time points. The confidence regions and simultaneous confidence limits

James J. Chen; Yi Tsong

1997-01-01

188

The chronic toxicity of ZnO nanoparticles and ZnCl2 to Daphnia magna and the use of different methods to assess nanoparticle aggregation and dissolution.  

PubMed

In this study, the effect of ZnO nanoparticles and ZnCl2 on growth, reproduction and accumulation of zinc in Daphnia magna was determined in a 21-day chronic toxicity test. A variety of techniques were used to distinguish the free zinc ion, dissolved, nanoparticle and aggregated zinc fraction in the Daphnia test medium. The results showed similar chronic effects on growth, reproduction and accumulation for the ZnO nanoparticles (EC10, 20, 50 reproduction: 0.030, 0.049, 0.112 mg Zn/l) and the ZnCl2 (EC10, 20, 50 reproduction: 0.014, 0.027, 0.082 mg Zn/l). A large fraction of the nanoparticles rapidly dissolved after introduction in the exposure medium. Aggregation of nanoparticles was also observed but within 48 h of exposure most of these ZnO aggregates were dissolved. Based on the combined dissolution kinetics and toxicity results, it can be concluded that the toxicological effects of ZnO nanoparticles at the chronic level can be largely attributed to the dissolved fraction rather than the nanoparticles or initially formed aggregates. PMID:23837602

Adam, Nathalie; Schmitt, Claudia; Galceran, Josep; Companys, Encarna; Vakurov, Alexander; Wallace, Rachel; Knapen, Dries; Blust, Ronny

2014-11-01

189

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

190

Comparing various techniques to produce micro/nanoparticles for enhancing the dissolution of celecoxib containing PVP.  

PubMed

One of the major challenges in pharmaceutical development is the poor dissolution performance of drugs. Celecoxib (CLX) is a poorly water soluble drug with its bioavailability being limited by its poor dissolution. In this study several particle engineering methods were employed on CLX using various ratios of CLX:PVP-K30. Micro/nanoparticles of CLX:PVP were prepared by using spray drying (SD), antisolvent crystallization followed by freeze drying (CRS-FD) and spray drying (CRS-SD) techniques. The suspension obtained through antisolvent crystallization was also subjected to high pressure homogenization followed by freeze drying (HPH-FD). Particle size measurements, saturation solubility, optical and scanning electron microscopy, DSC, XRPD, FT-IR and dissolution test were performed to characterize the physicochemical and pharmaceutical properties of the samples. The results showed that spray dried samples in the presence of (50%) PVP produced spherical particles and exhibited a high dissolution rate. Interestingly in the antisolvent crystallization technique, spherical nanoparticles of drug-PVP were obtained in the range of 291-442 nm. The average particle size was dependent on the concentration of the PVP used during the crystallization process. Solid state analysis showed that these particles were completely amorphous in nature. Also interesting to note was that at concentration of 5% PVP, when the suspension of nanoparticles was subjected to the high pressure homogenization process, the crystallinity of CLX increased. Despite the partial crystallinity of particles produced, they showed excellent dissolution behavior. It can thus be concluded that the method of preparation of CLX micro/nanoparticles had a big impact on the dissolution rate when the concentration of PVP was low (e.g., 5%). At high PVP concentration (e.g., 50%) all methods used to prepare engineered CLX particles showed better dissolution with no significant differences in their dissolution efficiency. PMID:24952357

Homayouni, Alireza; Sadeghi, Fatemeh; Varshosaz, Jaleh; Garekani, Hadi Afrasiabi; Nokhodchi, Ali

2014-09-01

191

Uranium dioxide dissolution under acidic aqueous conditions  

SciTech Connect

Understanding of the long-term dissolution of waste forms in groundwater is required for the safe disposal of high level nuclear waste in a geologic repository, because waste-form radionuclides could be released by dissolution and transported in groundwater. The dissolution of the uranium dioxide (UO{sub 2}) matrix in spent nuclear fuel is considered the rate-limiting step for release of radioactive fission products. The intrinsic UO{sub 2} dissolution rate sets an upper limit on the aqueous radionuclide release rate. Unsaturated spent fuel tests have shown that pH`s of leachates have decreased to a range of 4 to 6, presumably due to air radiolysis that oxidizes nitrogen, producing nitric acid. Dissolution rates under such acidic conditions may be different than those previously reported for alkaline groundwater conditions. No dissolution rate measurements of UO{sub 2} or spent fuel have been reported for acidic conditions possibly relevant to a geologic repository. The purpose of our work has been to measure the intrinsic dissolution rates of uranium dioxide under acidic conditions that are relevant to a repository and allow for modeling. Experiments have been completed at room-temperature and 75 C, pH`s of 4 and 6, and air and oxygen saturated aqueous solutions. These are compared with earlier work on spent fuel and UO{sub 2} using alkaline solutions.

Steward, S.A.; Mones, E.T.

1995-11-20

192

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 ...

193

Method for non-destructive testing  

DOEpatents

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

Akers, Douglas W. (Idaho Falls, ID)

2011-08-30

194

Moving and Union Dissolution  

PubMed Central

This paper examines the effect of migration and residential mobility on union dissolution among married and cohabiting couples. Moving is a stressful life event, and a large, multidisciplinary literature has shown that family migration often benefits one partner (usually the man) more than the other. Even so, no study to date has examined the possible impact of within-nation geographical mobility on union dissolution. We base our longitudinal analysis on retrospective event-history data from Austria. Our results show that couples who move frequently have a significantly higher risk of union dissolution, and we suggest a variety of mechanisms that may explain this. PMID:18390300

BOYLE, PAUL J.; KULU, HILL; COOKE, THOMAS; GAYLE, VERNON; MULDER, CLARAH.

2008-01-01

195

Simultaneous production and co-mixing of microparticles of nevirapine with excipients by supercritical antisolvent method for dissolution enhancement  

Microsoft Academic Search

Microparticles of a poorly water-soluble model drug, nevirapine (NEV) were prepared by supercritical antisolvent (SAS) method and simultaneously deposited on the surface of excipients such as lactose and microcrystalline cellulose in a single step to reduce drug–drug particle aggregation. In the proposed method, termed supercritical antisolvent-drug excipient mixing (SAS-DEM), drug particles were precipitated in supercritical CO2 vessel containing excipient particles

Ganesh P. Sanganwar; Sateeshkumar Sathigari; R. Jayachandra Babu; Ram B. Gupta

2010-01-01

196

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

197

Enhanced dissolution and stability of Tanshinone IIA base by solid dispersion system with nano-hydroxyapatite  

PubMed Central

Background: Tanshinone IIA (TSIIA) exhibits a variety of cardiovascular effects; however, it has low solubility in water. The preparation of poorly soluble drugs for oral delivery is one of the greatest challenges in the field of formulation research. Among the approaches available, solid dispersion (SD) technique has proven to be one of the most commonly used these methods for improving dissolution and bioavailability of drugs, because of its relative simplicity and economy in terms of both preparation and evaluation. Objective: This study was aimed at investigating the dissolution behavior and physical stability of SDs of TSIIA by employing nano-hydroxyapatite (n-HAp). Materials and Methods: The TSIIA SDs was prepared to use a spray-drying method. First, an in vitro dissolution test was performed to assess dissolution characteristics. Next, a set of complementary techniques (differential scanning calorimetry, scanning electron microscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy) was used to monitor the physicochemical properties of the SDs. The SDs was stored at 40°C/75% relative humidity for 6 months, after which their stability was assessed. Results: TSIIA dissolution remarkably improved because of the formulation of the SDs with n-HAp particles. Comparisons with the corresponding physical mixtures revealed changes in the SDs and explained the formation of the amorphous phase. In the stability test, virtually no time-dependent decrease was observed in either in vitro drug dissolution or drug content. Conclusion: SD formulation with n-HAp may be a promising approach for enhancing the dissolution and stability of TSIIA. PMID:25210322

Jiang, Yan-rong; Zhang, Zhen-hai; Huang, Sai-yan; Lu, Yan; Ma, Tian-tian; Jia, Xiao-bin

2014-01-01

198

Characterization methods for ultrasonic test systems  

SciTech Connect

Methods for the characterization of ultrasonic transducers (search units) and instruments are presented. The instrument system is considered as three separate components consisting of a transducer, a receiver-display, and a pulser. The operation of each component is assessed independently. The methods presented were chosen because they provide the greatest amount of information about component operation and were not chosen based upon such conditions as cost, ease of operation, field implementation, etc. The results of evaluating a number of commercially available ultrasonic test instruments are presented.

Busse, L.J.; Becker, F.L.; Bowey, R.E.; Doctor, S.R.; Gribble, R.P.; Posakony, G.J.

1982-07-01

199

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

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

200

Statistical assessment of dissolution and drug release profile similarity using a model-dependent approach  

Microsoft Academic Search

A general multivariate procedure for assessing the similarity of dissolution and drug release profiles was developed. A mathematical model is fit to the data, and Hotelling's T2 test is used to calculate the joint confidence region around the vector of differences between least-squares estimates of the parameters in the model. The method of Lagrange multipliers is used to determine if

Mark R. Berry; Michael D. Likar

2007-01-01

201

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

Microsoft Academic Search

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

E. Beyssac; J. Lavigne

202

Standard test method for plutonium assay by plutonium (III) diode array spectrophotometry  

E-print Network

1.1 This test method describes the determination of total plutonium as plutonium(III) in nitrate and chloride solutions. The technique is applicable to solutions of plutonium dioxide powders and pellets (Test Methods C 697), nuclear grade mixed oxides (Test Methods C 698), plutonium metal (Test Methods C 758), and plutonium nitrate solutions (Test Methods C 759). Solid samples are dissolved using the appropriate dissolution techniques described in Practice C 1168. The use of this technique for other plutonium-bearing materials has been reported (1-5), but final determination of applicability must be made by the user. The applicable concentration range for plutonium sample solutions is 10–200 g Pu/L. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropria...

American Society for Testing and Materials. Philadelphia

2002-01-01

203

Improved method for azole antifungal susceptibility testing.  

PubMed Central

A reproducible method is described for the determination of the MICs of ketoconazole, miconazole, fluconazole, and itraconazole with sharp endpoints when employed with either yeasts or molds. A semisolid medium is used with controlled pH and standardized inoculum. The time of reading results is a critical factor in the conduct of this test. The medium is simple to prepare and has a relatively long refrigerator shelf life in a user-ready state, requiring only the addition of a freshly prepared inoculum after restoration to room temperature. Images PMID:2846651

Gordon, M A; Lapa, E W; Passero, P G

1988-01-01

204

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

PubMed

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 Q?? 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 Q?? increased as particle size decreased. The bioavailability of coenzyme Q?? after oral administration in beagle dogs was improved by reducing the particle size. For 700 nm nanocrystals, the AUC???? 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. PMID:23166438

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

2012-01-01

205

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

206

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

207

Extension of Pack Method for Compressive Tests  

NASA Technical Reports Server (NTRS)

The pack method for determining compressive stress-strain graphs described in NACA Report No. 649 has been modified to extend it's application to thinner gages and stronger materials. The principal modifications consisted in the provision of additional support against instability cementing the specimens of the pack together with fused shellac and the provision of special clamps to hold the specimens together while the test is in progress. The shellac was found to increase the buckling load of the pack without any appreciable effect on the compressive stress-strain graph of the material. The extended pack method described in this note has made possible the application of stresses in excess of 220 kips per square inch to sheet material having a thickness of only 0.02 inch.

Aitchison, C S

1940-01-01

208

Mesh deployable antenna mechanics testing method  

NASA Astrophysics Data System (ADS)

Rapid development in spatial technologies and continuous expansion of astronautics applications require stricter and stricter standards in spatial structure. Deployable space structure as a newly invented structural form is being extensively adopted because of its characteristic (i.e. deployability). Deployable mesh reflector antenna is a kind of common deployable antennas. Its reflector consists in a kind of metal mesh. Its electrical properties are highly dependent on its mechanics parameters (including surface accuracy, angle, and position). Therefore, these mechanics parameters have to be calibrated. This paper presents a mesh antenna mechanics testing method that employs both an electronic theodolite and a laser tracker. The laser tracker is firstly used to measure the shape of radial rib deployable antenna. The measurement data are then fitted to a paraboloid by means of error compensation. Accordingly, the focus and the focal axis of the paraboloid are obtained. The following step is to synchronize the coordinate systems of the electronic theodolite and the measured antenna. Finally, in a microwave anechoic chamber environment, the electromechanical axis is calibrated. Testing results verify the effectiveness of the presented method.

Jiang, Li

209

40 CFR 63.827 - Performance test methods.  

Code of Federal Regulations, 2010 CFR

...Industry § 63.827 Performance test methods. (a) An owner...conduct an initial performance test to demonstrate compliance...monthly liquid-liquid material balance. (b) Determination...operator must submit an alternative test method for determining...

2010-07-01

210

40 CFR 63.180 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...Pollutants for Equipment Leaks § 63.180 Test methods and procedures...extend the duration of the test for the time necessary...procedure may be used for leak testing the equipment...be used to pressure-test batch...

2010-07-01

211

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

212

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

213

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

214

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

215

30 CFR 36.41 - Testing methods.  

Code of Federal Regulations, 2011 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ...MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Test Requirements § 36.41 Testing...Mobile diesel-powered transportation equipment submitted for certification and...

2011-07-01

216

30 CFR 36.41 - Testing methods.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ...MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Test Requirements § 36.41 Testing...Mobile diesel-powered transportation equipment submitted for certification and...

2013-07-01

217

30 CFR 36.41 - Testing methods.  

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ...MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Test Requirements § 36.41 Testing...Mobile diesel-powered transportation equipment submitted for certification and...

2014-07-01

218

30 CFR 36.41 - Testing methods.  

Code of Federal Regulations, 2012 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ...MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Test Requirements § 36.41 Testing...Mobile diesel-powered transportation equipment submitted for certification and...

2012-07-01

219

30 CFR 36.41 - Testing methods.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ...MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Test Requirements § 36.41 Testing...Mobile diesel-powered transportation equipment submitted for certification and...

2010-07-01

220

Diffusion with dissolution and precipitation in a porous media  

E-print Network

Diffusion with dissolution and precipitation in a porous media approximation by a finite volume.Herbin@cmi.univ-mrs.fr ABSTRACT. This paper study a finite volumes scheme for nonlinear diffusion and dissolution- precipitation two species in liquid phase and one species in solid phase. Some numerical tests are shown. RÃ?SUMÃ?

Herbin, Raphaèle

221

Understanding agglomeration of indomethacin during the dissolution of micronised indomethacin mixtures through dissolution and de-agglomeration modeling approaches.  

PubMed

The purpose of this research was to correlate the state of agglomeration determined by the modeling of dissolution and de-agglomeration profiles, using mixtures of micronised indomethacin designed to have different dissolution rates and extents of particle agglomeration in dissolution media. Dissolution profiles were determined using the USP paddle method. De-agglomeration profiles were obtained from laser diffraction particle sizing of mixtures of indomethacin in dissolution media under non-sink conditions. Data were modeled and key parameters estimated using a non-linear least squares estimation algorithm. The key parameters of initial apparent volume concentrations as dispersed and agglomerated particles, and dissolution rate constants (for dissolution modeling), and the apparent volume concentrations of dispersible and non-dispersible agglomerates and the de-agglomeration rate constant (for de-agglomeration modeling) were related to indomethacin and sodium lauryl sulphate concentrations in the lactose-povidone mixtures. Micronised sodium lauryl sulphate added to the mixture was more effective in de-agglomeration than equivalent concentrations in the dissolution media. An excellent correlation existed between the total initial apparent volume concentration of agglomerates determined by dissolution and de-agglomeration (P=0.98). The use of key parameters estimated from the modeling of dissolution and de-agglomeration profiles provides a useful tool in dosage form development of formulations of poorly water soluble drugs. PMID:15661504

Stewart, Peter J; Zhao, Feng-Ying

2005-02-01

222

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

223

Aqueous dissolution rates of uranium oxides  

SciTech Connect

An understanding of the long-term dissolution of waste forms in groundwater is required for the safe disposal of high level nuclear waste in an underground repository. The main routes by which radionuclides could be released from a geological repository are the dissolution and transport processes in groundwater flow. Because uranium dioxide is the primary constituent of spent nuclear fuel, the dissolution of its matrix in spent fuel is considered the rate-limiting step for release of radioactive fission products. The purpose of our work has been to measure the intrinsic dissolution rates of uranium oxides under a variety of well-controlled conditions that are relevant to a repository and allow for modeling. The intermediate oxide phase U{sub 3}O{sub 8}, triuranium octaoxide, is quite stable and known to be present in oxidized spent fuel. The trioxide, UO{sub 3}, has been shown to exist in drip tests on spent fuel. Here we compare the results of essentially identical dissolution experiments performed on depleted U{sub 3}O{sub 8} and dehyrated schoepite or uranium trioxide monohydrate (UO{sub 3}{center_dot}H{sub 2}O). These are compared with earlier work on spent fuel and UO{sub 2} under similar conditions.

Steward, S. A.; Mones, E. T.

1994-10-01

224

Testing methods and techniques: Environmental testing: A compilation  

NASA Technical Reports Server (NTRS)

Various devices and techniques are described for testing hardware and components in four special environments: low temperature, high temperature, high pressure, and vibration. Items ranging from an automatic calibrator for pressure transducers to a fixture for testing the susceptibility of materials to ignition by electric spark are included.

1971-01-01

225

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

226

Moving and union dissolution  

Microsoft Academic Search

This paper examines the effect of migration and residential mobility on union dissolution among married and cohabiting couples.\\u000a Moving is a stressful life event, and a large, multidisciplinary literature has shown that family migration often benefits\\u000a one partner (usually the man) more than the other. Even so, no study to date has examined the possible impact of within-nation\\u000a geographical mobility

Paul J. Boyle; Hill. Kulu; Vernon. Gayle; Clara Helena. Mulder

2008-01-01

227

Second phase dissolution  

Microsoft Academic Search

A detailed theoretical study was made of the dissolution of precipitates. The kinetic analyses of the atomic mechanisms included\\u000a the concurrent effects of diffusion, interface reaction, and curvature, and considered the more complex problems of precipitate\\u000a arrays and nondepleted matrices. The general formalism thus obtained was used to interpret the results of an experimental\\u000a investigation of the technologically important problem

Howard B. Aaron; Gerald R. Kotler

1971-01-01

228

[Study on holes testing methods of natural latex rubber condoms].  

PubMed

Designed a contrast pinhole detect testing including water leak method, electrical method and improved electrical method, and concluded that the water leak method is most suitable as the arbitration method, and recommended the national standard add the requirement on electrolytic liquid filling volume of electrical test in order to improve detection accuracy. PMID:23668044

Cao, Li; Li, Miao; Wu, Bitao; Wu, Mingjun

2013-01-01

229

40 CFR 63.827 - Performance test methods.  

Code of Federal Regulations, 2011 CFR

...the conditions of performance tests. (a) An owner or operator...conduct an initial performance test to demonstrate compliance if...monthly liquid-liquid material balance. (b) Determination...operator must submit an alternative test method for determining...

2011-07-01

230

CONTROLLED EVALUATION OF SILVER NANOPARTICLE DISSOLUTION USING ATOMIC FORCE MICROSCOPY  

EPA Science Inventory

Preliminary experiments have demonstrated that the proposed method can successfully measure dissolution rates in units of nm/d with high precision, and a strong correlation has been shown between chloride concentration and AgNP dissolution rate. Future experimentation will ...

231

DISSOLUTION OF PLUTONIUM METAL IN 8-10 M NITRIC ACID  

SciTech Connect

The H-Canyon facility will be used to dissolve Pu metal for subsequent purification and conversion to plutonium dioxide (PuO{sub 2}) using Phase II of HB-Line. To support the new mission, the development of a Pu metal dissolution flowsheet which utilizes concentrated (8-10 M) nitric acid (HNO{sub 3}) solutions containing potassium fluoride (KF) is required. Dissolution of Pu metal in concentrated HNO{sub 3} is desired to eliminate the need to adjust the solution acidity prior to purification by anion exchange. The preferred flowsheet would use 8-10 M HNO{sub 3}, 0.015-0.07 M KF, and 0.5-1.0 g/L Gd to dissolve the Pu up to 6.75 g/L. An alternate flowsheet would use 8-10 M HNO{sub 3}, 0.1-0.2 M KF, and 1-2 g/L B to dissolve the Pu. The targeted average Pu metal dissolution rate is 20 mg/min-cm{sup 2}, which is sufficient to dissolve a 'standard' 2250-g Pu metal button in 24 h. Plutonium metal dissolution rate measurements showed that if Gd is used as the nuclear poison, the optimum dissolution conditions occur in 10 M HNO{sub 3}, 0.04-0.05 M KF, and 0.5-1.0 g/L Gd at 112 to 116 C (boiling). These conditions will result in an estimated Pu metal dissolution rate of {approx}11-15 mg/min-cm{sup 2} and will result in dissolution times of 36-48 h for standard buttons. The recommended minimum and maximum KF concentrations are 0.03 M and 0.07 M, respectively. The maximum KF concentration is dictated by a potential room-temperature Pu-Gd-F precipitation issue at low Pu concentrations. The purpose of the experimental work described in this report was two-fold. Initially a series of screening experiments was performed to measure the dissolution rate of Pu metal as functions of the HNO{sub 3}, KF, and Gd or B concentrations. The objective of the screening tests was to propose optimized conditions for subsequent flowsheet demonstration tests. Based on the rate measurements, this study found that optimal dissolution conditions in solutions containing 0.5-1.0 g/L Gd occurred in 8-10 M HNO{sub 3} with 0.04-0.05 M KF at 112 to 116 C (boiling). The testing also showed that solutions containing 8-10 M HNO{sub 3}, 0.1-0.2 M KF, and 1-2 g/L B achieved acceptable dissolution rates in the same temperature range. To confirm that conditions identified by the dissolution rate measurements for solutions containing Gd or B can be used to dissolve Pu metal up to 6.75 g/L in the presence of Fe, demonstration experiments were performed using concentrations in the optimal ranges. In two of the demonstration experiments using Gd and in one experiment using B, the offgas generation during the dissolution was measured and samples were analyzed for H{sub 2}. The experimental methods used to perform the dissolution rate measurements and flowsheet demonstrations and a discussion of the results are presented.

Rudisill, T.; Pierce, R.

2012-02-21

232

Role of microbial iron reduction in the dissolution of iron hydroxysulfate minerals  

E-print Network

jarosite and schwertmannite at neutral pH by iron-reducing bacteria. Mineral dissolution was tested usingRole of microbial iron reduction in the dissolution of iron hydroxysulfate minerals Elizabeth J. P in mineral dissolution, releasing these bound contaminants. Reduction of structural sulfate in the iron

233

Regulatory perspectives on in vitro (dissolution)\\/in vivo (bioavailability) correlations  

Microsoft Academic Search

In vitro dissolution has been extensively used as a quality control tool for solid oral dosage forms. In several cases, however, it is not known whether one can predict the in vivo performance of these products from in vitro dissolution data. In an effort to minimize unnecessary human testing, investigations of in vitro\\/in vivo correlations (IVIVC) between in vitro dissolution

Venkata Ramana S Uppoor

2001-01-01

234

40 CFR 63.1161 - Performance testing and test methods.  

...the minimum recirculation water flow rate. During the emission...determine gas velocity and volumetric flow rate; (iii) Method 3, to...to determine the HCl mass flows at the inlet and outlet of a control device or the concentration...

2014-07-01

235

49 CFR 383.133 - Test methods.  

...FEDERAL MOTOR CARRIER SAFETY REGULATIONS COMMERCIAL DRIVER'S LICENSE STANDARDS; REQUIREMENTS...Skills tests must be conducted in on-street conditions or under a combination of on-street and off-street conditions. (5)...

2014-10-01

236

Polymer Testing 26 (2007) 614618 Short Communication: Test Method  

E-print Network

on mass production than on the field of compounding, which is dominated by small and medium-sized enterprises. Consequently, it lies with the latter to offer highly customized products at low prices, especially in the near infrared (NIR) frequency range [5,6]. However, each method is restricted to a small

Mittleman, Daniel

237

PERFORMANCE TESTING OF METHOD 1312-QA SUPPORT FOR RCRA TESTING  

EPA Science Inventory

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

238

[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

239

A Residual Mass Ballistic Testing Method to Compare Armor Materials or Components (Residual Mass Ballistic Testing Method)  

SciTech Connect

A statistics based ballistic test method is presented for use when comparing multiple groups of test articles of unknown relative ballistic perforation resistance. The method is intended to be more efficient than many traditional methods for research and development testing. To establish the validity of the method, it is employed in this study to compare test groups of known relative ballistic performance. Multiple groups of test articles were perforated using consistent projectiles and impact conditions. Test groups were made of rolled homogeneous armor (RHA) plates and differed in thickness. After perforation, each residual projectile was captured behind the target and its mass was measured. The residual masses measured for each test group were analyzed to provide ballistic performance rankings with associated confidence levels. When compared to traditional V50 methods, the residual mass (RM) method was found to require fewer test events and be more tolerant of variations in impact conditions.

Benjamin Langhorst; Thomas M Lillo; Henry S Chu

2014-05-01

240

Novel tests and inspection methods for textile reinforced composite tubes  

Microsoft Academic Search

Purpose: This paper describes innovative lightweight applications of fiber and textile reinforced polymers in aircraft, automotive and chemical industry. Design\\/methodology\\/approach: This paper deals with modern test methods of braided composite tube specimens as basic elements of modern composites. The tubes subjected to strength tests under superposed compressive, tensile and internal pressure loadings, and tested by the acoustic emission method for

W. Hufenbach; L. Kroll; M. Gude; A. Czulak; R. Böhm; M. Danczak

241

Automated Test Data Generation Using an Iterative Relaxation Method  

Microsoft Academic Search

An important problem that arises in path oriented testing is the generation of test data that causes a program to follow a given path. In this paper, we present a novel program execution based approach using an iterative relaxation method to address the above problem. In this method, test data generation is initiated with an arbitrarily chosen input from a

Neelam Gupta; Aditya P. Mathur; Mary Lou Soffa

1998-01-01

242

An eco-friendly strategy, using on-line monitoring and dilution coupled to a second-order chemometric method, for the construction of dissolution curves of combined pharmaceutical associations.  

PubMed

A simple, precise, economic and minimally operator-dependent method was developed under green analytical chemistry principles, for the simultaneous construction of the dissolution curves of a pharmaceutical association in short time and without employing organic solvents, allowing important savings of labor and resources. The carvedilol (CAR) and hydrochlorothiazide (HCT) combined formulation was employed as a model. The method (OD/UV-MCR) involves on-line sample dilution (OD) and UV detection of the analytes, coupled to multivariate curve resolution with alternating least squares (MCR-ALS). OD/UV-MCR proved to be robust and was successfully validated in accordance to ICH guidelines, fulfilling acceptance criteria for specificity (r(2) of spectral correlation>0.950), linearity [r>0.999 (N=25) in the ranges 1.00-31.1mg l(-1) and 0.51-15.2mg l(-1) for CAR and HCT, respectively] and precision (RSD<2%). Accuracy was assessed by point-to-point comparison between the dissolution profiles furnished by the proposed method with those provided by HPLC analysis, evidencing the usefulness of this monitoring system. In addition, OD/UV-MCR was successfully employed for the comparative analysis of three lots of commercial formulations of the CAR-HCT pharmaceutical association, belonging to a couple of different brands, employing Moore and Flanner's f2 similarity indicator. PMID:24291800

Calvo, Natalia L; Maggio, Rubén M; Kaufman, Teodoro S

2014-02-01

243

Test Methods for Plasticity and Extrusion Behaviour  

NASA Astrophysics Data System (ADS)

There is no generally acknowledged method or measuring unit to specify the extrusion behaviour of ceramic bodies. In order to obtain an adequately precise description of the extrusion behaviour, numerous specific methods do exist, which have to be chosen according to the material, for example for bodies to produce bricks and tiles or bodies for the manufacture of catalytic converters, as well as methods relating to specific application requirements, be it, for example, for the purposes of production, quality control or development of the body.

Göhlert, Katrin; Uebel, Maren

244

Tracer Test Interpretation Methods for Reservior Properties  

SciTech Connect

The purpose of this project is to develop tools that can be used to interpret tracer tests and obtain estimates of reservoir and operational parameters. These tools (mostly in the form of spreadsheet applications) can be used to optimize geothermal resource management.

Shook, George Michael

2001-08-01

245

Evaluation of SSME test data reduction methods  

NASA Astrophysics Data System (ADS)

Accurate prediction of hardware and flow characteristics within the Space Shuttle Main Engine (SSME) during transient and main-stage operation requires a significant integration of ground test data, flight experience, and computational models. The process of integrating SSME test measurements with physical model predictions is commonly referred to as data reduction. Uncertainties within both test measurements and simplified models of the SSME flow environment compound the data integration problem. The first objective of this effort was to establish an acceptability criterion for data reduction solutions. The second objective of this effort was to investigate the data reduction potential of the ROCETS (Rocket Engine Transient Simulation) simulation platform. A simplified ROCETS model of the SSME was obtained from the MSFC Performance Analysis Branch . This model was examined and tested for physical consistency. Two modules were constructed and added to the ROCETS library to independently check the mass and energy balances of selected engine subsystems including the low pressure fuel turbopump, the high pressure fuel turbopump, the low pressure oxidizer turbopump, the high pressure oxidizer turbopump, the fuel preburner, the oxidizer preburner, the main combustion chamber coolant circuit, and the nozzle coolant circuit. A sensitivity study was then conducted to determine the individual influences of forty-two hardware characteristics on fourteen high pressure region prediction variables as returned by the SSME ROCETS model.

Santi, L. Michael

1994-10-01

246

Test Oracles Using Statistical Methods Johannes Mayer, Ralph Guderlei  

E-print Network

Test Oracles Using Statistical Methods Johannes Mayer, Ralph Guderlei Abteilung Angewandte of random- ized software. The presented Statistical Oracle is a Heuristic Oracle using statistical methods, of characteristics computable from the test results are available. A Statistical Oracle using statistical methods

Pfeifer, Holger

247

DEVELOPMENT AND VALIDATION OF A TEST METHOD FOR FORMALDEHYDE EMSSION  

EPA Science Inventory

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

248

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. PMID:24300394

da Costa, Maíra Assis; Seiceira, Rafael Cardoso; Rodrigues, Carlos Rangel; Hoffmeister, Cristiane Rodrigues Drago; Cabral, Lucio Mendes; Rocha, Helvécio Vinícius Antunes

2012-01-01

249

40 CFR 60.64 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Portland Cement Plants § 60.64 Test methods and procedures. (a) In conducting the performance tests and relative accuracy...

2013-07-01

250

40 CFR 60.64 - Test methods and procedures.  

... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Portland Cement Plants § 60.64 Test methods and procedures. (a) In conducting the performance tests and relative accuracy...

2014-07-01

251

40 CFR 60.64 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Portland Cement Plants § 60.64 Test methods and procedures. (a) In conducting the performance tests required in § 60.8,...

2010-07-01

252

40 CFR 60.583 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

...Flexible Vinyl and Urethane Coating and Printing § 60.583 Test methods and procedures...minutes and shall continue until the printing operation is interrupted or until 180...each test run, the print line shall be printing continuously and operating...

2011-07-01

253

40 CFR 60.583 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Flexible Vinyl and Urethane Coating and Printing § 60.583 Test methods and procedures...minutes and shall continue until the printing operation is interrupted or until 180...each test run, the print line shall be printing continuously and operating...

2013-07-01

254

40 CFR 60.583 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...Flexible Vinyl and Urethane Coating and Printing § 60.583 Test methods and procedures...minutes and shall continue until the printing operation is interrupted or until 180...each test run, the print line shall be printing continuously and operating...

2012-07-01

255

40 CFR 60.583 - Test methods and procedures.  

...Flexible Vinyl and Urethane Coating and Printing § 60.583 Test methods and procedures...minutes and shall continue until the printing operation is interrupted or until 180...each test run, the print line shall be printing continuously and operating...

2014-07-01

256

STATUS AND APPLICATIONS OF ECHINOID (PHYLUM ECHINODERMATA) TOXICITY TEST METHODS  

EPA Science Inventory

The use of echinoderms for toxicity testing has focused primarily on sea urchins and sand dollars (Strongylocentrolus purpuratus, Arbacia punctulata, Lytechinus pictus, and Dendraster excentricus, for example). he status and relative sensitivity of various test methods are descri...

257

40 CFR 60.93 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

258

40 CFR 60.93 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

259

40 CFR 60.93 - Test methods and procedures.  

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

2014-07-01

260

40 CFR 60.93 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

261

40 CFR 60.93 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

262

40 CFR 60.485 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...Industry for which Construction, Reconstruction, or Modification Commenced After January 5, 1981, and on or Before November 7, 2006 § 60.485 Test methods and procedures. (a) In conducting the performance tests required in § 60.8, the...

2010-07-01

263

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

264

40 CFR 61.125 - Test methods and procedures.  

Code of Federal Regulations, 2011 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...

2011-07-01

265

40 CFR 61.125 - Test methods and procedures.  

...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...

2014-07-01

266

40 CFR 61.125 - Test methods and procedures.  

Code of Federal Regulations, 2010 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...

2010-07-01

267

40 CFR 61.125 - Test methods and procedures.  

Code of Federal Regulations, 2012 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...

2012-07-01

268

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

269

40 CFR 60.736 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Calciners and Dryers in Mineral Industries § 60.736 Test methods and procedures. (a) In conducting the performance tests required...

2011-07-01

270

40 CFR 60.736 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Calciners and Dryers in Mineral Industries § 60.736 Test methods and procedures. (a) In conducting the performance tests required...

2013-07-01

271

40 CFR 60.736 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Calciners and Dryers in Mineral Industries § 60.736 Test methods and procedures. (a) In conducting the performance tests required...

2012-07-01

272

40 CFR 60.736 - Test methods and procedures.  

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Calciners and Dryers in Mineral Industries § 60.736 Test methods and procedures. (a) In conducting the performance tests required...

2014-07-01

273

40 CFR 60.736 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Calciners and Dryers in Mineral Industries § 60.736 Test methods and procedures. (a) In conducting the performance tests required...

2010-07-01

274

Method and apparatus for gripping test specimens  

NASA Astrophysics Data System (ADS)

A pair of solid-teeth wedges are employed in an improved gripping system. The wedges fit inside a pair of plates having an angled cavity to accommodate them. As stress is applied to the specimen, the wedges are urged toward the specimen by the angled cavity to increase the gripping force. An alignment fixturing device is used to properly position the grips on the test specimen. This device not only axially aligns the grips but also locates them at the proper spacing.

Mackay, Rebecca A.; Nathal, Michael V.

1992-05-01

275

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

276

A Method of Partly Automated Testing of Software  

NASA Technical Reports Server (NTRS)

A method of automated testing of software has been developed that provides an alternative to the conventional mostly manual approach for software testing. The method combines (1) automated generation of test cases on the basis of systematic exploration of the input domain of the software to be tested with (2) run-time analysis in which execution traces are monitored, verified against temporal-logic specifications, and analyzed by concurrency-error-detection algorithms. In this new method, the user only needs to provide the temporal logic specifications against which the software will be tested and the abstract description of the input domain.

Lowry, Mike; Visser, Willem; Washington, Rich; Artho, Cyrille; Goldberg, Allen; Haveland, Klaus; Pasareanu, Corina; Khurshid, Sarfraz; Roflu, Grigore

2007-01-01

277

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

SciTech Connect

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

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

1993-01-01

278

SEA URCHIN (STRONGYLOCENTROTUS PURPURATUS) FERTILIZATION TEST METHOD  

EPA Science Inventory

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

279

Methods for certifying test gas mixtures  

Microsoft Academic Search

The most common colorimetric method of determining small concentrations of oxygen (from 0.001 to 1% by volume) is based on the conversion of monovalent copper ions into bivalent ions by oxidation with the oxygen contained in the analyzed gas. Bivalent copper ions form with ammonia a blue-colored compound. The intensity of coloring thus obtained is compared with the coloring of

É. M. Malkova; T. L. Radovskaya; M. P. Belozerova; Z. T. Berestneva

1963-01-01

280

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

281

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

282

Marital Dissolution and Psychiatrie Disorders  

Microsoft Academic Search

Simple and moderated associations between 12-month prevalence of marital dissolution and 12-month prevalence of mood, anxiety, and substance use disorders were evaluated. Moderators examined were demographic (gender, length of marriage, race\\/ethnicity) and distal (parental death, parental marital dissolution, parental mental illness) variables. Compared with continuously married individuals, people who divorced or separated were at elevated risk for mood, anxiety, and

Yael Chatav; Mark A. Whisman

2007-01-01

283

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

284

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

285

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

286

40 CFR 60.715 - Test methods and procedures.  

...CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Magnetic Tape Coating Facilities § 60.715 Test methods and procedures. Methods in appendix A of this part, except as...

2014-07-01

287

40 CFR 60.715 - 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 Magnetic Tape Coating Facilities § 60.715 Test methods and procedures. Methods in appendix A of this part, except as...

2013-07-01

288

40 CFR 60.715 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Magnetic Tape Coating Facilities § 60.715 Test methods and procedures. Methods in appendix A of this part, except as...

2011-07-01

289

40 CFR 60.715 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Magnetic Tape Coating Facilities § 60.715 Test methods and procedures. Methods in appendix A of this part, except as...

2012-07-01

290

Methods for The Testing of Nanopowders , Ch. de Izarra2  

E-print Network

. For instance, the analysis of tungsten carbide nanopowders has shown that it consists of the WC1-x phase. The objective of this work is an overview of existing testing methods, analysis of these methods adequacy

Paris-Sud XI, Université de

291

40 CFR 63.786 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

292

40 CFR 63.786 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

293

40 CFR 63.786 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

294

40 CFR 63.786 - Test methods and procedures.  

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

2014-07-01

295

40 CFR 63.786 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

296

Design of a dissolution system for the evaluation of the release rate characteristics of artemether and dihydroartemisinin from tablets.  

PubMed

As none of the pharmacopoeial dissolution methods are suitable to evaluate the release rate of artemether and dihydroartemisinin from tablets, a 'two-phase partition-dissolution' method, based on the one of [J. Pharm. Sci. 85 (1996) 1060] was developed. It consists of an organic solvent in the upper part and the aqueous phase, in which the dissolution test was executed. The main requirements for the selection of the solvent are: the density should be lower than 1; the analyte should dissolve in the organic part as much as required for 'sink' conditions; if possible, the cut off should be near 200 nm, which allows direct HPLC measurement at 215 nm. The most suitable solvent for artemether is isooctane in a ratio of 100/150 ml aqueous phase. Samples could be analysed without further treatment. For dihydroartemisinin, chlorobutane was selected in a ratio 150/150 ml water. In the latter method, the solvent disturbed in the HPLC analysis and therefore samples were evaporated and then reconstituted in methanol. Repeatability of the test was satisfactory and discrimination ability tests on Artenam tablet batches and self-made dihydroartemisinin tablets, respectively, showed good results, confirmed via calculation of the similarity factor f2 (value <50). Dissolution determination of Cotecxin tablets was proven not to be conform as immediate-release tablet. PMID:15072800

Gabriëls, M; Plaizier-Vercammen, J

2004-04-15

297

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

298

Eddy Current Method for Fatigue Testing  

NASA Technical Reports Server (NTRS)

Flux-focusing electromagnetic sensor using a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks and material loss in high conductivity material. A ferrous shield isolates a high-turn pick-up coil from an excitation coil. Use of the magnetic shield produces a null voltage output across the receiving coil in presence of an unflawed sample. Redistribution of the current flow in the sample caused by the presence of flaws. eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. Maximum sensor output is obtained when positioned symmetrically above the crack. By obtaining position of maximum sensor output, it is possible to track the fault and locate the area surrounding its tip. Accuracy of tip location is enhanced by two unique features of the sensor; a very high signal-to-noise ratio of the probe's output resulting in an extremely smooth signal peak across the fault, and a rapidly decaying sensor output outside a small area surrounding the crack tip enabling the search region to be clearly defined. Under low frequency operation, material thinning due to corrosion causes incomplete shielding of the pick-up coil. Low frequency output voltage of the probe is therefore a direct indicator of thickness of the test sample. Fatigue testing a conductive material is accomplished by applying load to the material, applying current to the sensor, scanning the material with the sensor, monitoring the sensor output signal, adjusting material load based on the sensor output signal of the sensor, and adjusting position of the sensor based on its output signal.

Simpson, John W. (Inventor); Fulton, James P. (Inventor); Wincheski, Russell A. (Inventor); Todhunter, Ronald G. (Inventor); Namkung, Min (Inventor); Nath, Shridhar C. (Inventor)

1997-01-01

299

Methods of testing parameterizations: Vertical ocean mixing  

NASA Technical Reports Server (NTRS)

The ocean's velocity field is characterized by an exceptional variety of scales. While the small-scale oceanic turbulence responsible for the vertical mixing in the ocean is of scales a few centimeters and smaller, the oceanic general circulation is characterized by horizontal scales of thousands of kilometers. In oceanic general circulation models that are typically run today, the vertical structure of the ocean is represented by a few tens of discrete grid points. Such models cannot explicitly model the small-scale mixing processes, and must, therefore, find ways to parameterize them in terms of the larger-scale fields. Finding a parameterization that is both reliable and plausible to use in ocean models is not a simple task. Vertical mixing in the ocean is the combined result of many complex processes, and, in fact, mixing is one of the less known and less understood aspects of the oceanic circulation. In present models of the oceanic circulation, the many complex processes responsible for vertical mixing are often parameterized in an oversimplified manner. Yet, finding an adequate parameterization of vertical ocean mixing is crucial to the successful application of ocean models to climate studies. The results of general circulation models for quantities that are of particular interest to climate studies, such as the meridional heat flux carried by the ocean, are quite sensitive to the strength of the vertical mixing. We try to examine the difficulties in choosing an appropriate vertical mixing parameterization, and the methods that are available for validating different parameterizations by comparing model results to oceanographic data. First, some of the physical processes responsible for vertically mixing the ocean are briefly mentioned, and some possible approaches to the parameterization of these processes in oceanographic general circulation models are described in the following section. We then discuss the role of the vertical mixing in the physics of the large-scale ocean circulation, and examine methods of validating mixing parameterizations using large-scale ocean models.

Tziperman, Eli

1992-01-01

300

Modeling gas dissolution in deepwater oil/gas spills  

NASA Astrophysics Data System (ADS)

Gases in deepwater oil/gas spills can lose considerable amounts of the gas phase due to dissolution in water. Gas dissolution has a significant impact on the behavior of the oil/gas jet/plume because of its impact on the buoyancy. A method is presented in this paper for computing gas dissolution that covers a broad range of water depth, from shallow water where gases behave as ideal ones under low pressure to deepwater where gases behave as non-ideal ones under high pressures. The method presented also accounts for the spherical and non-spherical shapes of gas bubbles. The gas dissolution computations are validated by comparing the computed results with observed data from previously conducted laboratory experiments. The gas dissolution computation module is then integrated with a model for underwater oil/gas jets/plumes by Yapa and Zheng [J. Hydraul. Res. 35 (5) (1997) 673]. Scenario simulations are presented to show the impacts of gas dissolution on the behavior of jets/plumes. These scenarios show the impact of dissolution on the behavior of the jet/plume. The comparison of results using ideal gas conditions and non-ideal gas conditions is also shown.

Zheng, Li; Yapa, Poojitha D.

2002-01-01

301

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

302

Statistical Tests for Evaluating Earthquake Prediction Methods Kurt S. Riedel  

E-print Network

Statistical Tests for Evaluating Earthquake Prediction Methods Kurt S. Riedel Courant Institute methodology fails to forecast the earthquakes. We formulate a statistical test for this possibil­ ity cited as VAN]. The central argument is whether the VEVL method predicts better than random chance

303

40 CFR 63.694 - Testing methods and procedures.  

...2014-07-01 2014-07-01 false Testing methods and procedures. 63.694 Section 63.694...Hazardous Air Pollutants from Off-Site Waste and Recovery Operations § 63.694 Testing methods and procedures. (a) This section...

2014-07-01

304

40 CFR 63.694 - Testing methods and procedures.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Testing methods and procedures. 63.694 Section 63.694...Hazardous Air Pollutants from Off-Site Waste and Recovery Operations § 63.694 Testing methods and procedures. (a) This section...

2012-07-01

305

40 CFR 63.694 - Testing methods and procedures.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Testing methods and procedures. 63.694 Section 63.694...Hazardous Air Pollutants from Off-Site Waste and Recovery Operations § 63.694 Testing methods and procedures. (a) This section...

2011-07-01

306

40 CFR 63.694 - Testing methods and procedures.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Testing methods and procedures. 63.694 Section 63.694...Hazardous Air Pollutants from Off-Site Waste and Recovery Operations § 63.694 Testing methods and procedures. (a) This section...

2013-07-01

307

40 CFR 63.365 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

...Sterilization Facilities § 63.365 Test methods and procedures. ...weight percent of compound in the balance of the mixture MWx =molecular weight of compound in the balance gas mixture (ii) The...40 CFR part 60, appendix A, Test Methods 2, 2A, 2C,...

2011-07-01

308

40 CFR 63.365 - Test methods and procedures.  

...Sterilization Facilities § 63.365 Test methods and procedures. ...weight percent of compound in the balance of the mixture MWx = molecular weight of compound in the balance gas mixture (ii) The...40 CFR part 60, appendix A, Test Methods 2, 2A, 2C,...

2014-07-01

309

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

310

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

311

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

312

Statistical investigation of two different interlayer shear test methods  

Microsoft Academic Search

The performance of multi-layered pavement systems strongly depends on interlayer bonding. In order to evaluate this parameter,\\u000a some countries have developed their own test method. However, different devices generally provide different results due to\\u000a the test conditions. In this article, the statistical investigation of two interlayer shear test methods is shown considering\\u000a different asphalt materials and different specimen preparation techniques.

Felice A. Santagata; Gilda Ferrotti; Manfred N. Partl; Francesco Canestrari

2009-01-01

313

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

Federal Register 2010, 2011, 2012, 2013

...sensitization test methods and testing strategies. The National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative...6, 2013. John R. Bucher, Associate Director, National Toxicology Program. [FR Doc. 2013-27095 Filed 11-12-13;...

2013-11-13

314

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

Code of Federal Regulations, 2010 CFR

...40 Protection of Environment 6 2010-07-01 2010-07-01 false What test methods...Which Construction is Commenced After August 30, 1999 or for Which Modification...Reconstruction is Commenced After June 6, 2001 Stack Testing §...

2010-07-01

315

The Science of USP 1 and 2 Dissolution: Present Challenges and Future Relevance  

Microsoft Academic Search

Since its inception, the dissolution test has come under increasing levels of scrutiny regarding its relevance, especially\\u000a to the correlation of results to levels of drug in blood. The technique is discussed, limited to solid oral dosage forms,\\u000a beginning with the scientific origins of the dissolution test, followed by a discussion of the roles of dissolution in product\\u000a development, consistent

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

2009-01-01

316

Methods for testing the strength of cancellous bone and tested method effects on cortical bone in the ovariectomized rat  

E-print Network

In this study, two mechanical testing procedures were developed to test the strength of cancellous bone from the proximal tibia of the rat, the "punch method" and the "whole slice method". These were used to quantify the effect of ovariectomy on rat...

Ruhmann, Sean Phillip

2012-06-07

317

Insulator icing test methods and procedures: a position paper prepared by the IEEE task force on insulator icing test methods  

Microsoft Academic Search

Test methods for evaluating flashover voltage of ceramic and nonceramic insulators under ice, snow, and cold-fog conditions are recommended. The paper describes the procedure to be followed at various stages of an evaluation test including preparation of the test object, insulator precontamination, ice, snow, and cold-fog deposits as well as voltage applications and flashover voltage evaluation. Some relevant parameters for

M. Farzaneh; T. Baker; A. Bernstorf; K. Brown; W. A. Chisholm; C. de Tourreil; J. F. Drapeau; S. Fikke; J. M. George; E. Gnandt; T. Grisham; I. Gutman; R. Hartings; R. Kremer; G. Powell; L. Rolfseng; T. Rozek; D. L. Ruff; D. Shaffner; V. Sklenicka; R. Sundararajan; J. Yu

2003-01-01

318

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

319

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

320

Using Formal Methods To Derive Test Frames In Category-Partition Testing  

E-print Network

unsatis - able as de ned by Kemmerer Kem85 speci cations. We employ formal methods, in particular Z speci A variety of researchers have investigated the use of formal methods in test generation. Kemmerer sug

Offutt, Jeff

321

40 CFR 60.466 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...SOURCES Standards of Performance for Metal Coil Surface Coating § 60.466 Test methods...coating as applied to the surface of the metal coil. In the event of a dispute, Method...as applied to the surface of the metal coil. (c) For Method 25, the...

2010-07-01

322

Mesoporous carbon with spherical pores as a carrier for celecoxib with needle-like crystallinity: improve dissolution rate and bioavailability.  

PubMed

The purposes of this investigation are to design mesoporous carbon (MC) with spherical pore channels and incorporate CEL to it for changing its needlelike crystal form and improving its dissolution and bioavailability. A series of solid-state characterization methods, such as SEM, TEM, DSC and XRD, were employed to systematically investigate the existing status of celecoxib (CEL) within the pore channels of MC. The pore size, pore volume and surface area of samples were characterized by nitrogen physical absorption. Gastric mucosa irritation test was carried out to evaluate the safety of mesoporous carbon as a drug carrier. Dissolution tests and in vivo pharmacokinetic studies were conducted to confirm the improvement in drug dissolution kinetics and oral bioavailability. Uptake experiments were conducted to investigate the mechanism of the improved oral bioavailability. The results of solid state characterization showed that MC was prepared successfully and CEL was incorporated into the mesoporous channels of the MC. The crystallinity of CEL in MC was affected by different loading methods, which involve evaporation method and melting method. The dissolution rate of CEL from MC was found to be significantly higher than that of pure CEL, which attributed to reduced crystallinity of CEL. The gastric mucosa irritation test indicated that the MC caused no harm to the stomach and produced a protective effect on the gastric mucosa. Uptake experiments indicated that MC enhanced the amount of CEL absorbed by Caco-2 cells. Moreover, oral bioavailability of CEL loaded within the MC was approximately 1.59-fold greater than that of commercial CEL. In conclusion, MC was a safe carrier to load water insoluble drug by controlling the crystallinity or crystal form with improvement in drug dissolution kinetics and oral bioavailability. PMID:24863191

Zhu, Wenquan; Zhao, Qinfu; Sun, Changshan; Zhang, Zhiwen; Jiang, Tongying; Sun, Jin; Li, Yaping; Wang, Siling

2014-06-01

323

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

324

Dissolution behavior of commercial enteric-coated aspirin tablets.  

PubMed

Dissolution behavior was studied for four commercial batches of enteric-coated aspirin tablets from two companies. The USP XIX dissolution procedure was modified by including pretreatment in simulated gastric juice. The effects of five pretreatment times were studied. Pretreated tablets yielded higher dissolution profiles and fewer undissolved fractions than nonpretreated tablets. Among pretreatments, 15 min was adequate and 60 min produced the highest dissolution profiles. None of the pretreatments differed significantly from each other. An F test and conducted on the data indicated that Product X was significantly better than Product Y at the p=0.05 level. Batch C was ranked as the best batch irrespective of pretreatment time, followed by Batch D. Batches A and B were equal, although Batch A appeared to be better than B for the 60-min pretreatment, as indicated by the lower t80% value. PMID:512863

Embil, K; Torosian, G

1979-10-01

325

Dissolution of materials in artificial skin surface film liquids.  

PubMed

The dissolution of chemical constituents from jewelry, textiles, cosmetics, drugs, industrial chemicals, and particles in direct and prolonged contact with human skin is often assessed in vitro using artificial skin surface film liquids (SSFL). To provide meaningful results, the composition of artificial SSFL should accurately mimic human sweat and sebum, and the conditions of the in vitro test system should accurately reflect in vivo skin conditions. We summarized the reported composition of human SSFL and compared it to 45 different formulations of artificial sweat and 18 formulations of artificial sebum (studies published from 1940 to 2005). Conditions of in vitro dissolution test systems were reviewed and compared to in vivo skin conditions. The concentrations of individual constituents and pH of artificial sweat and concentrations of artificial sebum constituents are not always within ranges reported for human SSFL. Nearly all artificial SSFL lack many of the constituents in human SSFL. To develop a comprehensive model SSFL, we propose a standard SSFL, modified from the two best published sweat and sebum formulations. Little is known concerning the influence of test system conditions on dissolution, including SSFL temperature, container material composition, agitation, and physicochemical properties of the test article on dissolution. Thus, both a need and an opportunity exist for standardizing the composition of artificial SSFL and in vitro dissolution test methodologies. To standardize in vitro dissolution test systems, we recommend: maintaining artificial SSFL at a biologically relevant temperature appropriate to the human activity being modeled, carefully selecting test and sample storage containers to avoid bias in dissolution measurements, accounting for friction between a test article and skin in a biologically plausible manner, and physicochemical characterization of the test article or material to better understand mechanisms of dissolution and potential mechanisms of toxic action of dissolved material. More accurate modeling and better understanding of chemical dissolution from articles in contact with the skin will ultimately improve risk decision making, thereby protecting even the most susceptible persons from adverse health effects resulting from skin exposure. PMID:16860531

Stefaniak, Aleksandr B; Harvey, Christopher J

2006-12-01

326

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. PMID:16230632

Dove, Patricia M.; Han, Nizhou; De Yoreo, James J.

2005-01-01

327

Saltcake Dissolution FY 2002 Status Report  

SciTech Connect

Laboratory tests were completed on the dissolution characteristics of Hanford saltcake waste from single-shell waste tanks 241-B-109 and 241-SX-101 (henceforth referred to as B-109 and SX-101). 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 relevant 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. Cascade (or ''stepwise'') dissolution tests were performed on composite saltcake samples from both tanks. The purpose of these tests is to evaluate the solid/liquid phase distribution of chemicals and radionuclides during tank waste retrieval operations. Solid phase identification tests were also performed on saltcake from both tanks. Weight percent (wt%) dilution is defined in this report as 100 times the weight of diluent (water or 2 M NaOH solution) divided by the weight of undiluted saltcake composite sample. A 50% dilution, for example, would be 50 g of H{sub 2}O (or 50 g of 2 M NaOH) added to 100 g of undiluted composite sample. Volume percent (Vol%) dilution is defined as 100 times the volume of diluent divided by the calculated volume of undiluted sample. Weight percent dilutions are measured directly by weighing the undiluted sample and diluent. Volume percent dilutions are estimated from the known volume of diluent and calculated volume of undiluted sample.

HERTING, D.L.

2002-09-26

328

Standardization of fretting fatigue test methods and equipment  

SciTech Connect

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

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

1992-01-01

329

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

330

40 CFR 264.1063 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 264.1063 Test methods and procedures. (a) Each owner or operator...procedures requirements provided in this section. (b) Leak detection monitoring, as required in §§...

2010-07-01

331

40 CFR 265.1063 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1063 Test methods and procedures. (a) Each owner or operator...procedures requirements provided in this section. (b) Leak detection monitoring, as required in §§...

2010-07-01

332

40 CFR 60.204 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

... STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Wet-Process Phosphoric Acid Plants § 60.204 Test methods and procedures. (a) In conducting the...

2010-07-01

333

40 CFR 60.224 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

... STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Diammonium Phosphate Plants § 60.224 Test methods and procedures. (a) In conducting the performance...

2010-07-01

334

40 CFR 60.214 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

... STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Superphosphoric Acid Plants § 60.214 Test methods and procedures. (a) In conducting the performance...

2010-07-01

335

40 CFR 60.435 - Test methods and procedures.  

...OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Graphic Arts Industry: Publication Rotogravure Printing § 60.435 Test methods and procedures. (a) The owner or operator of any affected facility using...

2014-07-01

336

40 CFR 63.365 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...Ethylene Oxide Emissions Standards for Sterilization Facilities § 63.365 Test methods...section. (b) Efficiency at the sterilization chamber vent. The following procedures...to comply with § 63.362(c), sterilization chamber vent standard. (1)...

2010-07-01

337

40 CFR 60.474 - Test methods and procedures.  

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

2014-07-01

338

40 CFR 60.474 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

339

40 CFR 60.474 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

340

40 CFR 60.474 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

341

40 CFR 60.46 - Test methods and procedures.  

...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...

2014-07-01

342

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

343

40 CFR 60.46 - Test methods and procedures.  

Code of Federal Regulations, 2012 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...

2012-07-01

344

40 CFR 61.137 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Benzene Emissions from Coke By-Product Recovery Plants § 61.137 Test methods and procedures. (a) Each owner or operator subject to the...

2012-07-01

345

40 CFR 61.137 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Benzene Emissions from Coke By-Product Recovery Plants § 61.137 Test methods and procedures. (a) Each owner or operator subject to the...

2010-07-01

346

40 CFR 61.137 - Test methods and procedures.  

...CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Benzene Emissions from Coke By-Product Recovery Plants § 61.137 Test methods and procedures. (a) Each owner or operator subject to the...

2014-07-01

347

40 CFR 61.137 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Benzene Emissions from Coke By-Product Recovery Plants § 61.137 Test methods and procedures. (a) Each owner or operator subject to the...

2013-07-01

348

40 CFR 61.137 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

...CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Benzene Emissions from Coke By-Product Recovery Plants § 61.137 Test methods and procedures. (a) Each owner or operator subject to the...

2011-07-01

349

40 CFR 60.74 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

350

40 CFR 60.74 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

351

40 CFR 60.74 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

352

40 CFR 60.74 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

353

40 CFR 60.133 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Standards of Performance for Secondary Brass and Bronze Production Plants § 60.133 Test methods and procedures...and refining, but not during pouring of part of the production cycle. The sampling time and sample volume for...

2013-07-01

354

40 CFR 60.133 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...Standards of Performance for Secondary Brass and Bronze Production Plants § 60.133 Test methods and procedures...and refining, but not during pouring of part of the production cycle. The sampling time and sample volume for...

2010-07-01

355

40 CFR 60.133 - Test methods and procedures.  

...Standards of Performance for Secondary Brass and Bronze Production Plants § 60.133 Test methods and procedures...and refining, but not during pouring of part of the production cycle. The sampling time and sample volume for...

2014-07-01

356

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

357

40 CFR 60.133 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...Standards of Performance for Secondary Brass and Bronze Production Plants § 60.133 Test methods and procedures...and refining, but not during pouring of part of the production cycle. The sampling time and sample volume for...

2012-07-01

358

40 CFR 60.133 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

...Standards of Performance for Secondary Brass and Bronze Production Plants § 60.133 Test methods and procedures...and refining, but not during pouring of part of the production cycle. The sampling time and sample volume for...

2011-07-01

359

40 CFR 76.15 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

360

40 CFR 76.15 - Test methods and procedures.  

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

2014-07-01

361

40 CFR 76.15 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

362

40 CFR 76.15 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

363

40 CFR 76.15 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

364

40 CFR 60.224 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Diammonium Phosphate Plants § 60.224 Test methods and procedures. (a) In conducting the...

2013-07-01

365

40 CFR 60.224 - Test methods and procedures.  

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Diammonium Phosphate Plants § 60.224 Test methods and procedures. (a) In conducting the...

2014-07-01

366

40 CFR 60.204 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Wet-Process Phosphoric Acid Plants § 60.204 Test methods and procedures. (a) In conducting...

2012-07-01

367

40 CFR 60.214 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Superphosphoric Acid Plants § 60.214 Test methods and procedures. (a) In conducting the...

2013-07-01

368

40 CFR 60.244 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

369

40 CFR 60.214 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Superphosphoric Acid Plants § 60.214 Test methods and procedures. (a) In conducting the...

2012-07-01

370

40 CFR 60.204 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Phosphate Fertilizer Industry: Wet-Process Phosphoric Acid Plants § 60.204 Test methods and procedures. (a) In conducting...

2013-07-01

371

40 CFR 60.244 - Test methods and procedures.  

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

2014-07-01

372

Comparison of bulk sediment and sediment elutriate toxicity testing methods  

EPA Science Inventory

Elutriate bioassays are among numerous methods that exist for assessing the potential toxicity of sediments in aquatic systems. In this study, interlaboratory results were compared from 96-hour Ceriodaphnia dubia and Pimephales promelas static-renewal acute toxicity tests conduct...

373

40 CFR 60.285 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Kraft Pulp Mills § 60.285 Test methods and procedures...samples. (3) When determining whether a furnace is a straight kraft recovery furnace or a cross recovery furnace, TAPPI...

2010-07-01

374

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

375

Simulation test method for deterioration of engine crankshaft oil seals  

SciTech Connect

This paper introduces a new simulation test method by using IR analysis which is capable of evaluating the rate of deterioration of VMQ (Silicone) rubber material applied in engine crankshaft seal applications. IR analysis is used to measure the rate of change of the Si-C/Si-O ratio which indicates the level of deterioration of VMQ material from the hydrolysis of the siloxane bond. Applying the new analysis method, laboratory test conditions could be improved to more closely simulate field conditions.

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

1990-01-01

376

A method for testing association patterns of social animals  

Microsoft Academic Search

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

LARS BEJDER; DAVID FLETCHER; STEFAN BRÄGER

1998-01-01

377

Fire test methods for electrical and dielectric materials  

Microsoft Academic Search

Methods intended for the measurement of combustibility are briefly reviewed. The need for fire safety assessment to address parameters that extend beyond a material's tendency to burn is discussed. Emphasis is placed on recent developments in fire testing which provide a more complete characterization of a material's fire behavior and associated fire hazards. Fire test apparatus and toxicity and corrosivity

Robert Buch; Dow Corning Corp

1990-01-01

378

An alternative method of decreasing ?K FCGR testing  

Microsoft Academic Search

The conventional technique of decreasing ?K FCGR testing often presents experimental difficulties in terms of the length of crack that must be accommodated and the time required to reach low values of ?K. Addressing these issues, an alternative method of conducting such tests has been proposed. A relation according to which ?K must be decreased has been derived assuming that

S Sivaprasad; S Tarafder; M Tarafder; K. K Ray

2000-01-01

379

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

380

Comparison of two methods of fatigue testing bone cement.  

PubMed

Two different methods have been used to fatigue test four bone cements. Each method has been used previously, but the results have not been compared. The ISO 527-based method tests a minimum of 10 samples over a single stress range in tension only and uses Weibull analysis to calculate the median number of cycles to failure and the Weibull modulus. The ASTM F2118 test regime uses fewer specimens at various stress levels tested in fully reversed tension-compression, and generates a stress vs. number of cycles to failure (S-N) or Wöhler curve. Data from specimens with pores greater than 1mm across is rejected. The ISO 527-based test while quicker to perform, provides only tensile fatigue data, but the material tested includes pores, thus the cement is closer to cement in clinical application. The ASTM regime uses tension and compression loading and multiple stress levels, thus is closer to physiological loading, but excludes specimens with defects obviously greater than 1mm, so is less representative of cement in vivo. The fatigue lives between the cements were up to a factor 15 different for the single stress level tension only tests, while they were only a factor of 2 different in the fully reversed tension-compression testing. The ISO 527-based results are more sensitive to surface flaws, thus the differences found using ASTM F2118 are more indicative of differences in the fatigue lives. However, ISO 527-based tests are quicker, so are useful for initial screening. PMID:19766742

Tanner, K E; Wang, Jian-Sheng; Kjellson, Fred; Lidgren, Lars

2010-03-01

381

Gall-stone dissolution and recurrence: are we being misled?  

PubMed Central

Oral cholecystography repeated at six-months intervals is the standard method for determining reduction in size of gall stones (partial success) and complete dissolution of stones (complete success). In a comparative study of oral cholecystography and cholecystosonography six out of 14 patients with gall stones achieving complete success by oral cholecystographic criteria had stones still detectable by ultrasonography. Repeat oral cholecystography in a further 11 patients receiving post-dissolution maintenance treatment detected stones in two, whereas ultrasonography detected stones in seven. In future complete dissolution of gall stones should be reported only if both oral cholecystography and ultrasonographic studies give negative results and the progress of patients receiving post-dissolution maintenance treatment is monitored by ultrasonography rather than serial oral cholecystography. PMID:6803946

Somerville, K W; Rose, D H; Bell, G D; Ellis, W R; Knapp, D R

1982-01-01

382

Gall-stone dissolution and recurrence: are we being misled?  

PubMed

Oral cholecystography repeated at six-months intervals is the standard method for determining reduction in size of gall stones (partial success) and complete dissolution of stones (complete success). In a comparative study of oral cholecystography and cholecystosonography six out of 14 patients with gall stones achieving complete success by oral cholecystographic criteria had stones still detectable by ultrasonography. Repeat oral cholecystography in a further 11 patients receiving post-dissolution maintenance treatment detected stones in two, whereas ultrasonography detected stones in seven. In future complete dissolution of gall stones should be reported only if both oral cholecystography and ultrasonographic studies give negative results and the progress of patients receiving post-dissolution maintenance treatment is monitored by ultrasonography rather than serial oral cholecystography. PMID:6803946

Somerville, K W; Rose, D H; Bell, G D; Ellis, W R; Knapp, D R

1982-05-01

383

Dissolution Curve Comparisons through the F2 parameter, a Bayesian extension of the f2 statistic.  

PubMed

Abstract Dissolution (or in vitro release) studies constitute an important aspect of pharmaceutical drug development. One important use of such studies is for justifying a biowaiver for post-approval changes which requires establishing equivalence between the new and old product (FDA, 1997c). We propose a statistically rigorous modeling approach for this purpose based on the estimation of what we refer to as the F2 parameter, an extension of the commonly used f2 statistic. A Bayesian test procedure is proposed in relation to a set of composite hypotheses that capture the similarity requirement on the absolute mean differences between test and reference dissolution profiles. Several examples are provided to illustrate the application. Results of our simulation study comparing the performance of f2 and the proposed method show that our Bayesian approach is comparable to or in many cases superior to the f2 statistic as a decision rule. Further useful extensions of the method are also indicated such as the use of dissolution models that are continuous in time. PMID:25357203

Novick, Steven; Shen, Yan; Yang, Harry; Peterson, John; LeBlond, Dave; Altan, Stan

2014-10-30

384

Testing methods and techniques: Testing electrical and electronic devices: A compilation  

NASA Technical Reports Server (NTRS)

The methods, techniques, and devices used in testing various electrical and electronic apparatus are presented. The items described range from semiconductor package leak detectors to automatic circuit analyzer and antenna simulators for system checkout. In many cases the approaches can result in considerable cost savings and improved quality control. The testing of various electronic components, assemblies, and systems; the testing of various electrical devices; and the testing of cables and connectors are explained.

1972-01-01

385

Developing the ability to model acid-rock interactions and mineral dissolution during the RMA stimulation test performed at the Soultz-sous-Forêts EGS site, France  

NASA Astrophysics Data System (ADS)

The Soultz Enhanced Geothermal System (EGS) reservoir's response to chemical stimulation is assessed by numerical simulation of coupled thermo-hydraulic-chemical processes. To assess chemical interactions between host rocks and a mixture of HCl and HF as well as its potential effects on the Soultz EGS reservoir, new modelling efforts using the FRACHEM code have been initiated. This article presents the model calibration and results. Simulations consider realistic conditions with available data sets from the EGS system at Soultz. Results indicate that the predicted amount of fracture sealing minerals dissolved by injection of a mixture of acids Regular Mud Acid (RMA) was consistent with the estimated amount from the test performed on GPK4 well at Soultz EGS site. Consequently reservoir porosity and permeability can be enhanced especially near the injection well by acidizing treatment.

Portier, Sandrine; Vuataz, François D.

2010-07-01

386

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%. For comparison, other techniques were employed as well, including the Archimedes method, metallographic image analysis, X-ray diffraction, and acid dissolution. Observations indicated that ultrasonic testing and acid dissolution methods are more reliable than the other techniques, while ultrasonic testing is faster than the acid dissolution method.

Fang, C.K.; Fang, R.L.; Weng, W.P.; Chuang, T.H.

1999-10-01

387

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

388

Rate-Limiting Steps of Oral Absorption for Poorly Water-Soluble Drugs in Dogs; Prediction from a Miniscale Dissolution Test and a Physiologically-Based Computer Simulation  

Microsoft Academic Search

Purpose  Nonlinear oral absorption due to poor solubility often impedes drug development. The purpose of this study was to elucidate\\u000a the rate-limiting process in oral absorption of Biopharmaceutical Classification System (BCS) class II (low solubility–high\\u000a permeability) drugs in order to predict nonlinear absorption of dose caused by solubility-limited absorption.\\u000a \\u000a \\u000a \\u000a Methods  Oral absorption of danazol, griseofulvin, and aprepitant was predicted from a miniscale

Ryusuke Takano; Kentaro Furumoto; Koji Shiraki; Noriyuki Takata; Yoshiki Hayashi; Yoshinori Aso; Shinji Yamashita

2008-01-01

389

Review of Standard Test methods for Moisture in Lint Cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Almost all of the standard test methods for moisture in lint cotton utilize the oven-drying technique. The loss in weight is taken as the amount of water and is expressed as a percentage of the mass of either the moist or dried material. There is a need to review the standard methods and compare t...

390

40 CFR 60.534 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

...Standards of Performance for New Residential Wood Heaters § 60.534 Test methods and procedures...Method 28A shall be used to determine that a wood combustion unit qualifies under the definition of wood heater in § 60.531(a). If such a...

2010-07-01

391

40 CFR 60.534 - Test methods and procedures.  

...Standards of Performance for New Residential Wood Heaters § 60.534 Test methods and procedures...Method 28A shall be used to determine that a wood combustion unit qualifies under the definition of wood heater in § 60.531(a). If such a...

2014-07-01

392

40 CFR 60.534 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...Standards of Performance for New Residential Wood Heaters § 60.534 Test methods and procedures...Method 28A shall be used to determine that a wood combustion unit qualifies under the definition of wood heater in § 60.531(a). If such a...

2012-07-01

393

40 CFR 60.534 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...Standards of Performance for New Residential Wood Heaters § 60.534 Test methods and procedures...Method 28A shall be used to determine that a wood combustion unit qualifies under the definition of wood heater in § 60.531(a). If such a...

2013-07-01

394

40 CFR 60.534 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

...Standards of Performance for New Residential Wood Heaters § 60.534 Test methods and procedures...Method 28A shall be used to determine that a wood combustion unit qualifies under the definition of wood heater in § 60.531(a). If such a...

2011-07-01

395

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

396

Method to control the amount of helium during leak testing  

SciTech Connect

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

Frank E. Jurvic, Jr.

2002-03-29

397

Simulation of In Vitro Dissolution Behavior Using DDDPlus™  

PubMed

Dissolution testing is a performance test for many dosage forms including tablets and capsules. The objective of this study was to evaluate if computer simulations can predict the in vitro dissolution of two model drugs for which different dissolution data were available. Published montelukast sodium and glyburide dissolution data was used for the simulations. Different pharmacopeial and biorelevant buffers, volumes, and rotations speeds were evaluated. Additionally, a pH change protocol was evaluated using these buffers. DDDPlus™ 3, Beta version (Simulation Plus, Inc.), was used to simulate the in vitro dissolution data. The simulated data were compared with the in vitro data. A regression coefficient between predicted and observed data was used to assess the simulations. The statistical analysis of Montelukast sodium showed that there was a significant correlation between the in vitro release data and the predicted data for all cases except for one buffer. For glyburide, there was also a significant correlation between the experimental data and the predicted data using single pH conditions. Using the dynamic pH protocol, a correlation was significant for one biorelevant media. The simulations showed that both in vitro drug releases were sensitive to solubility effects which confirmed their BCS class II category. Computer simulations of the in vitro release using DDDPlus™ have the potential to estimate the in vivo dissolution at an early stage in the drug development process. This might be used to choose the most appropriate dissolution condition to establish IVIVC and to develop biorelevant in vitro performance tests to capture critical product attributes for quality control procedures in quality by design environments. PMID:25409918

Almukainzi, May; Okumu, Arthur; Wei, Hai; Löbenberg, Raimar

2014-11-20

398

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

399

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

400

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

401

Dissolution of quartz in aqueous basic solution, 106-236 C - Surface kinetics of 'perfect' crystallographic faces  

NASA Technical Reports Server (NTRS)

A highly accurate method, called the negative crystal method, for determining the rate of dissolution on specific crystallographic faces of crystals was developed, in which the dissolution rates of nominally perfect crystal faces are obtained by measuring the size of individual negative crystals during a sequence of dissolution steps. The method was applied to determine the apparent activation energy and rate constants for the dissolution of quartz in 0.01 M KOH solutions at temperatures from 106 to 236 C. Also investigated were the effects of hydroxyl activity and ionic strength. The apparent activation energies for the dissolution of the prism and of the rhomb were determined.

Gratz, Andrew J.; Bird, Peter; Quiro, Glenn B.

1990-01-01

402

Bioequivalence of tacrolimus formulations with different dynamic solubility and in-vitro dissolution profiles.  

PubMed

This study was to evaluate the pharmacokinetics and bioequivalence of two tacrolimus formulations which had different in vitro drug release profiles. Dynamic solubility, in vitro dissolution profiles of the two formulations, and their influence on pharmacokinetics were examined. The male volunteers were randomly assigned to receive a single 1-mg capsule of the test or reference formulation and pharmacokinetic parameters were determined using a noncompartmental method. The two formulations released >85 % of tacrolimus in water within 30 min, which passed the criterion of evaluating the test formulation. However, the test formulation produced a faster initial release rate and plateaued in about 15 min, while the reference showed almost zero order initial release profiles. The AUC0-? values were 145.92 (reference) and 140.49 ng h/mL (test). The mean Cmax was 15.70 (reference) and 16.08 ng/mL (test) with Tmax values of 1.63 and 1.60 h, respectively. The t1/2 for the reference and test formulations was 29.12 and 27.85 h, respectively. Relative bioavailability was calculated to be 96.28 %. The point estimates for the mean ratio of the test to reference for the AUC0-t and Cmax were 0.969 and 1.026, respectively, satisfying the criterion for bioequivalence. The results suggest that the test formulation is pharmacokinetically equivalent to the reference in terms of both rate and extent of absorption. Even though the in vitro dissolution profiles of the formulations might not be equivalent, the pharmacokinetics indicated bioequivalence. Therefore, when developing poorly soluble drugs, it might be beneficial to pay attention to the dynamic solubility as well as dissolution profiles. PMID:24627339

Kwon, Minchang; Yeom, Daeil; Kim, Nam Ah; Choi, Du Hyung; Park, Junsang; Wang, Hunsik; Yoo, Sun Dong; Jeong, Seong Hoon

2015-01-01

403

[Comparison between 2 elution methods for biological testing of materials].  

PubMed

The possibility of separating the eluate and the actual biologic test for determining tissue tolerance was studied using two cements containing copper and two cements without copper. Both the materials and the two eluates obtained according to the different procedures were tested immediately. Distilled water was added to one sample of the material, and the mixture was placed in an autoclave for one hour. A second sample was leached in nutrient solution for 24 hours at 37 C. Uniform results were obtained with the copper-free material. Results with the material containing copper however varied; the results of the eluate obtained after one hour in the autoclave were different from the results obtained after 24 hours in the nutrient solution or after direct testing. The test results for the last two procedures were similar. Comparison of the two elution methods indicates that extraction in physiologic nutrient solution is better than the autoclave method using distilled water. PMID:365516

Schmalz, G

1978-12-01

404

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

405

[Weibull equation and dissolution kinetics].  

PubMed

On modelling the kinetics of dissolution, two variants of Weibull equation in a two-parameter or tree-parameter form are used, the estimations of their parameters not being quite comparable. The introductory part of the paper sums up four variants of the equation and chracterized their relationship to granulometric Rosin-Rammler-Sperling equation. The kinetics of liberation of pilocarpinium chloride from lyophilized lamellae with graded amounts of hydroxypropylmethylcellulose is expressed by the above-mentioned equations and their parameters are compared. The conclusions generally discusses the usability of equations and their correct interperetation in modelling dissolution of active ingrediens from dosage forms. PMID:15631003

Zatloukal, Z

2004-11-01

406

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

PubMed

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

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

2013-10-01

407

Further development of the losipescu shear test method  

Microsoft Academic Search

Recent activities by the present investigators to further develop the losipescu-shear-test method for use with composite materials\\u000a are summarized. Finite-element analyses used to predict the stress states in the specimen are described, with particular emphasis\\u000a on how they are influenced by the specific test-fixture configuration used. These same analytical tools were also used to\\u000a predict the influence of specimen notch

D. F. Adams; D. E. Walrath

1987-01-01

408

A Model Based Security Testing Method for Protocol Implementation  

PubMed Central

The security of protocol implementation is important and hard to be verified. Since the penetration testing is usually based on the experience of the security tester and the specific protocol specifications, a formal and automatic verification method is always required. In this paper, we propose an extended model of IOLTS to describe the legal roles and intruders of security protocol implementations, and then combine them together to generate the suitable test cases to verify the security of protocol implementation. PMID:25105163

Fu, Yu Long; Xin, Xiao Long

2014-01-01

409

A method for testing association patterns of social animals.  

PubMed

Association indices were originally developed to describe species co-occurrences, but have been used increasingly to measure associations between individuals. However, no statistical method has been published that allows one to test the extent to which the observed association index values differ from those of a randomly associating population. Here, we describe an adaptation of a test developed by Manly (1995, Ecology, 76, 1109-1115), which uses the observed association data as a basis for a computer-generated randomization. The observed pattern of association is tested against a randomly created one while retaining important features of the original data, for example group size and sighting frequency. We applied this new method to test four data sets of associations from two populations of Hector's dolphin, Cephalorhynchus hectori, using the Half-Weight Index (HWI) as an example of a measure of association. The test demonstrated that populations with similar median HWI values showed clear differences in association patterns, that is, some were associating nonrandomly whereas others were not. These results highlight the benefits of using this new testing method in order to validate the analysis of association indices. Copyright 1998 The Association for the Study of Animal Behaviour. PMID:9784222

Bejder; Fletcher; BrÄger

1998-09-01

410

Method and apparatus for testing surface characteristics of a material  

NASA Technical Reports Server (NTRS)

A method, apparatus and system for testing characteristics of a material sample is provided. The system includes an apparatus configured to house the material test sample while defining a sealed volume against a surface of the material test sample. A source of pressurized fluid is in communication with, and configured to pressurize, the sealed volume. A load applying apparatus is configured to apply a defined load to the material sample while the sealed volume is monitored for leakage of the pressurized fluid. Thus, the inducement of surface defects such as microcracking and crazing may be detected and their effects analyzed for a given material. The material test samples may include laminar structures formed of, for example, carbon cloth phenolic, glass cloth phenolic, silica cloth phenolic materials or carbon-carbon materials. In one embodiment the system may be configured to analyze the material test sample while an across-ply loading is applied thereto.

Johnson, David L. (Inventor); Kersker, Karl D. (Inventor); Richardson, David E. (Inventor); Stratton, Troy C. (Inventor)

2006-01-01

411

Truncated Product Methods for Panel Unit Root Tests*  

PubMed Central

This paper proposes two new panel unit root tests based on Zaykin et al. (2002)’s truncated product method. The first one assumes constant correlation between p-values and the second one uses sieve bootstrap to allow for general forms of cross-section dependence in the panel units. Monte Carlo simulation shows that both tests have reasonably good size and are powerful in cases of some very large p-values. The proposed tests are applied to a panel of real GDP and inflation density forecasts, resulting in evidence that professional forecasters may not update their forecast precision in an optimal Bayesian way. PMID:23869116

SHENG, XUGUANG; YANG, JINGYUN

2012-01-01

412

High Level Waste System Impacts from Acid Dissolution of Sludge  

SciTech Connect

This research evaluates the ability of OLI{copyright} equilibrium based software to forecast Savannah River Site High Level Waste system impacts from oxalic acid dissolution of Tank 1-15 sludge heels. Without further laboratory and field testing, only the use of oxalic acid can be considered plausible to support sludge heel dissolution on multiple tanks. Using OLI{copyright} and available test results, a dissolution model is constructed and validated. Material and energy balances, coupled with the model, identify potential safety concerns. Overpressurization and overheating are shown to be unlikely. Corrosion induced hydrogen could, however, overwhelm the tank ventilation. While pH adjustment can restore the minimal hydrogen generation, resultant precipitates will notably increase the sludge volume. OLI{copyright} is used to develop a flowsheet such that additional sludge vitrification canisters and other negative system impacts are minimized. Sensitivity analyses are used to assess the processability impacts from variations in the sludge/quantities of acids.

KETUSKY, EDWARD

2006-04-20

413

Synergistic Effect of Hydrotrope and Surfactant on Solubility and Dissolution of Atorvastatin Calcium: Screening Factorial Design Followed by Ratio Optimization  

PubMed Central

The present study was aimed at investigating the effect of hydrotrope and surfactant on poor solubility of atorvastatin calcium. Excipients screening followed by factorial design was performed to study effect of excipients and manufacturing methods on solubility of drug. Three independent factors (carrier, surfactant and manufacturing method) were evaluated at two levels using solubility as a dependant variable. Solid-state characterisation was performed using Fourier transform infrared spectroscopy and differential scanning calorimetry. Optimised complex were incorporated into orally disintegrating micro tablets and in vitro dissolution test was performed. Nicotinamide, Plasdone and sodium dodecyl sulphate were emerged as promising excipients from excipient screening. General regression analysis revealed only the type of carrier has significantly enhanced (P<0.05) the solubility of drug while other factors were found to be nonsignificant. Ratio optimisation trial revealed that drug to nicotinamide ratio is more critical in enhancing the solubility of drug (40 fold increases in solubility compared to pure drug) in comparison to drug-surfactant ratio; however the presence of surfactant deemed essential. Significantly higher rate and extent of dissolution was observed from solid dispersion complex and tablets compared to dissolution of pure drug (P<0.05). Study revealed hydrotrope and surfactant have synergistic effect on solubility and dissolution of atorvastatin calcium and this can be explored further.

Patel, V. F.; Sarai, J.

2014-01-01

414

Dissolution criticality in developing solid oral formulations: from inception to perception.  

PubMed

Currently, dissolution testing has become a vital tool for accessing product performance, especially in the hierarchy of solid oral dosage forms. With advances in complicated, expensive, and sophisticated analytical instruments, characterization of formulations has become easier, but simple dissolution assembly is gradually gaining momentum from industrial environs as well as regulatory agencies. As such, simple dissolution testing involves many complexities which must be properly understood to reach correct conclusions. The appropriate selection of multiple parameters (e.g., apparatus, medium, agitation, etc.) involved in dissolution testing and understanding their impact on analysis require thorough subject knowledge. In the words of regulatory provisions, in vitro dissolution testing can become a surrogate for expensive and tedious bioequivalence studies in special cases (i.e., when a biowaiver is recommended). As a consequence, reduced human testing as well as lower product development cost ultimately benefit patients and society. Therefore, the dissolution science has recently become one of the keys for success for formulation scientists, especially generic manufacturers. While designing dissolution methodologies, generic manufacturers need to follow the respective regulatory guidelines at the product development stage; concomitant data are required for the approval process. This comprehensive review is an earnest attempt to acquaint readers with the history, contemporary practices, and relevant issues regarding dissolution which may become a guiding tool for overcoming challenges and opening better prospects in product development. PMID:24099398

Patadia, Riddhish; Vora, Chintan; Mittal, Karan; Mashru, Rajashree

2013-01-01

415

NON-DESTRUCTIVE TESTING METHODS FOR GEOTHERMAL PIPING.  

SciTech Connect

Non-destructive testing is a key component of optimized plant inspection and maintenance programs. Risk based inspection, condition based maintenance and reliability centered maintenance systems all require detection, location and sizing of defects or flaws by non-destructive methods. Internal damage of geothermal piping by corrosion and erosion-corrosion is an ongoing problem requiring inspection and subsequent maintenance decisions to ensure safe and reliable performance. Conventional manual ultrasonic testing to determine remaining wall thickness has major limitations, particularly when damage is of a random and localized nature. Therefore, it is necessary to explore alternative non-destructive methods that offer potential benefits in terms of accurate quantification of size, shape and location of damage, probability of detection, ability to use on-line over long ranges, and economics. A review of non-destructive methods and their applicability to geothermal piping was performed. Based on this, ongoing research will concentrate on long range guided wave and dynamic methods.

BERNDT,M.L.

2001-03-23

416

Modification of proportion sensitivity testing method for ethionamide.  

PubMed

Standardized methodology for drug susceptibility testing of second line drugs is vital for treatment of multi/extensively drug resistant tuberculosis. Discrepancy between laboratory methods and clinical interpretation is well established for bacteriostatic drugs such as ethionamide. Optimization of the standard proportion sensitivity testing (PST) method for ethionamide was under taken in 235 Mycobacterium tuberculosis isolates from new and previously treated pulmonary tuberculosis patients. An additional higher concentration of 57 ?g/ml was evaluated against at the standard 40 ?g/ml concentration in PST method. Performance parameters and agreement between the two drug concentrations was higher indicating the efficiency of PST method at its present format at 40 ?g/ml and additional higher concentration of 57 ?g/ml as an alternative when required. PMID:23315266

Lakshmi, Rajagopalan; Ramachandran, Ranjani; Devika, K; Radhika, G; Syam Sundar, A; Rahman, Fathima; Selvakumar, N; Kumar, Vanaja

2013-06-01

417

Laboratory simulation of salt dissolution during waste removal  

SciTech Connect

Laboratory experiments were performed to support the field demonstration of improved techniques for salt dissolution in waste tanks at the Savannah River Site. The tests were designed to investigate three density driven techniques for salt dissolution: (1) Drain-Add-Sit-Remove, (2) Modified Density Gradient, and (3) Continuous Salt Mining. Salt dissolution was observed to be a very rapid process as salt solutions with densities between 1.38-1.4 were frequently removed. Slower addition and removal rates and locating the outlet line at deeper levels below the top of the saltcake provided the best contact between the dissolution water and the saltcake. It was observed that dissolution with 1 M sodium hydroxide solution resulted in salt solutions that were within the current inhibitor requirements for the prevention of stress corrosion cracking. This result was independent of the density driven technique. However, if inhibited water (0.01 M sodium hydroxide and 0.011 M sodium nitrite) was utilized, the salt solutions were frequently outside the inhibitor requirements. Corrosion testing at conditions similar to the environments expected during waste removal was recommended.

Wiersma, B.J.; Parish, W.R.

1997-01-01

418

The role of soil pH in the dissolution of phosphate rock fertilizers  

Microsoft Academic Search

The influence of soil pH on the dissolution of phosphate rock fertilizers was investigated in laboratory experiments with reactive North Carolina phosphate rock (PR) in a lateritic soil adjusted to several pH values. Increased soil pH resulted in decreased dissolution as estimated by the increase in exchangeable calcium (?Ca) method. The extent of PR dissolution was related to soil pH

I. A. K. Kanabo; R. J. Gilkes

1987-01-01

419

Inversion method to test radial structures in cylindrical plasmas  

Microsoft Academic Search

A new method was developed to investigate radial structures of cylindrically symmetrical plasmas, based on the evaluation\\u000a of the integrated intensity distribution using modified Abel inversion. The method reduces the well known error sensitivity\\u000a of measurements and the restrictions owing to analytically invertable functions are avoided. In addition to numerical tests,\\u000a experiments were carried out with optically thin lines of

K. G. Antal; J. F. Bitó; F. Halász

1987-01-01

420

Asteroid Dynamical Families: a Reliability Test for Two Identification Methods  

NASA Astrophysics Data System (ADS)

Since a couple of years the asteroid families are under the light of a renewed interest. This is due to the simultaneous improvement of the techniques of proper elements computation and of the methods of classification. Recently, two different cluster analysis methods (Zappalà et al. 1990; Bendjoya et al. 1991) have provided two very similar lists of asteroid families. This has brought a renewed confidence on the reliability of asteroid families classification. Since a new set of improved proper elements is now available (Milani & Kneževi? 1992), the idea of the present work is to test the two identification methods by means of artificially generated families in order to gain an insight into their limitations and to possibly develop improved strategies for future analyses. Different cases have been envisaged in order to study the effectiveness of the methods as a function of increasing background densities and of the spread of the families. The ability of the methods to detect peculiar features such as filaments or to separate two close families has also been tested. The number of interlopers has been determined in each case in order to evaluate their relative amount. While some improvements to the adopted procedures are suggested by the numerical tests, the results presented in the present paper are encouraging and allow us to be confident about the reliability of our previous family lists, as well as about the expected performances of the methods in future applications.

Bendjoya, P.; Cellino, A.; Froeschle, C.; Zappala, V.

1993-05-01

421

Detection of fatigue cracks by nondestructive testing methods  

NASA Technical Reports Server (NTRS)

The effectiveness was assessed of various NDT methods to detect small tight cracks by randomly introducing fatigue cracks into aluminum sheets. The study included optimizing NDT methods calibrating NDT equipment with fatigue cracked standards, and evaluating a number of cracked specimens by the optimized NDT methods. The evaluations were conducted by highly trained personnel, provided with detailed procedures, in order to minimize the effects of human variability. These personnel performed the NDT on the test specimens without knowledge of the flaw locations and reported on the flaws detected. The performance of these tests was measured by comparing the flaws detected against the flaws present. The principal NDT methods utilized were radiographic, ultrasonic, penetrant, and eddy current. Holographic interferometry, acoustic emission monitoring, and replication methods were also applied on a reduced number of specimens. Generally, the best performance was shown by eddy current, ultrasonic, penetrant and holographic tests. Etching provided no measurable improvement, while proof loading improved flaw detectability. Data are shown that quantify the performances of the NDT methods applied.

Anderson, R. T.; Delacy, T. J.; Stewart, R. C.

1973-01-01

422

Formulations for iron oxides dissolution  

DOEpatents

A mixture of a di- or polyphosphonic acid and a reductant wherein each is present in a sufficient amount to provide a synergistic effect with respect to the dissolution of metal oxides and optionally containing corrosion inhibitors and pH adjusting agents.

Horwitz, Earl P. (Argonne, IL); Chiarizia, Renato (Argonne, IL)

1992-01-01

423

Gas hydrate dissolution rates quantified with laboratory and seafloor experiments  

NASA Astrophysics Data System (ADS)

Methane hydrates are stable at high pressure, low temperature, and saturated methane concentrations. However, natural hydrates exist at the seafloor where methane concentrations are well below saturation. Under such conditions, hydrate outcrops should shrink rapidly as they dissolve into the surrounding seawater. However, some natural hydrate outcrops have been observed for years undergoing little to no visible signs of change. Further, hydrate dissolution rates vary greatly among sites where changes have been observed. In this study, we perforated a natural hydrate outcrop on the seafloor of the Gulf of Mexico and measured the expansion of the hole after 30 days. From the rate of volume loss, we calculated a dissolution rate of 15 cm y-1. This rate is nearly an order of magnitude slower than hydrate dissolution rates observed in the Northern Cascadia Margin. We hypothesized that crystal structure influences hydrate dissolution rates and that the variability observed in in situ hydrate dissolution is caused by different hydrate structures. To test this hypothesis, we measured methane hydrate (structure I) and propane hydrate (structure II) dissolution rates in a series of laboratory experiments. Hydrates were formed in a pressure vessel and maintained at pressure and temperature conditions conducive to hydrate stability. After formation, the gas source was removed. Dissolution rates were calculated by measuring the increase in the dissolved gas concentration over time. Structure I (methane) hydrate dissolved at an average rate of 5.2 ± 2.5 mM CH4 d-1. Structure II (propane) hydrate dissolved at an average rate of 0.3 ± 0.2 mM C3H8 d-1. The ratio of these dissolution rates was proportional to the ratio of methane and propane solubilities under the experimental conditions. This suggests that dissolution rates in our experiments were diffusion-controlled and not influenced by differences in the crystal structure. We propose that natural contaminants such as oils or biofilms may have slowed the dissolution rate of the hydrate we observed in the Gulf of Mexico.

Lapham, Laura L.; Wilson, Rachel M.; MacDonald, Ian R.; Chanton, Jeffrey P.

2014-01-01

424

25 CFR 11.606 - Dissolution proceedings.  

Code of Federal Regulations, 2010 CFR

... (a) Either or both parties to the marriage may initiate dissolution proceedings...petition in a proceeding for dissolution of marriage or legal separation shall allege that the marriage is irretrievably broken and shall set...

2010-04-01

425

25 CFR 11.606 - Dissolution proceedings.  

... (a) Either or both parties to the marriage may initiate dissolution proceedings...petition in a proceeding for dissolution of marriage or legal separation shall allege that the marriage is irretrievably broken and shall set...

2014-04-01

426

25 CFR 11.606 - Dissolution proceedings.  

Code of Federal Regulations, 2011 CFR

... (a) Either or both parties to the marriage may initiate dissolution proceedings...petition in a proceeding for dissolution of marriage or legal separation shall allege that the marriage is irretrievably broken and shall set...

2011-04-01

427

25 CFR 11.606 - Dissolution proceedings.  

Code of Federal Regulations, 2012 CFR

... (a) Either or both parties to the marriage may initiate dissolution proceedings...petition in a proceeding for dissolution of marriage or legal separation shall allege that the marriage is irretrievably broken and shall set...

2012-04-01

428

25 CFR 11.606 - Dissolution proceedings.  

Code of Federal Regulations, 2013 CFR

... (a) Either or both parties to the marriage may initiate dissolution proceedings...petition in a proceeding for dissolution of marriage or legal separation shall allege that the marriage is irretrievably broken and shall set...

2013-04-01

429

16 CFR 1509.6 - Component-spacing test method.  

Code of Federal Regulations, 2010 CFR

...SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR NON-FULL-SIZE BABY CRIBS § 1509.6 Component-spacing test method. The apex of the wedge (see § 1509.5(a)) shall be placed midway between two vertical components and midway between the uppermost...

2010-01-01

430

40 CFR 60.64 - Test methods and procedures  

Code of Federal Regulations, 2012 CFR

...NEW STATIONARY SOURCES Standards of Performance for Portland Cement Plants § 60.64 Test methods and procedures (a... and SO2 as the total of all hourly emissions data for a cement kiln in the preceding 30 days, divided by the total tons...

2012-07-01

431

40 CFR 60.64 - Test methods and procedures  

Code of Federal Regulations, 2011 CFR

...NEW STATIONARY SOURCES Standards of Performance for Portland Cement Plants § 60.64 Test methods and procedures (a... and SO2 as the total of all hourly emissions data for a cement kiln in the preceding 30 days, divided by the total tons...

2011-07-01

432

40 CFR 60.404 - Test methods and procedures.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

433

40 CFR 60.404 - Test methods and procedures.  

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

2014-07-01

434

40 CFR 60.404 - Test methods and procedures.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

435

40 CFR 60.404 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

436

40 CFR 60.404 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

437

TROPICAL COLLECTOR URCHIN, TRIPNEUSTES GRATILLA, FERTILIZATION TEST METHOD  

EPA Science Inventory

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

438

Heart rate-based lactate minimum test: a reproducible method  

Microsoft Academic Search

OBJECTIVE: To find the individual intensity for aerobic endurance training, the lactate minimum test (LMT) seems to be a promising method. LMTs described in the literature consist of speed or work rate-based protocols, but for training prescription in daily practice mostly heart rate is used. The aim of the present study was to investigate the reproducibility of a new heart

M. Strupler; G Mueller; C. Perret

2009-01-01

439

Reproduction of natural corrosion by accelerated laboratory testing methods  

SciTech Connect

Various laboratory corrosion tests have been developed to study the behavior of glass waste forms under conditions similar to those expected in an engineered repository. The data generated by laboratory experiments are useful for understanding corrosion mechanisms and for developing chemical models to predict the long-term behavior of glass. However, it is challenging to demonstrate that these test methods produce results that can be directly related to projecting the behavior of glass waste forms over time periods of thousands of years. One method to build confidence in the applicability of the test methods is to study the natural processes that have been taking place over very long periods in environments similar to those of the repository. In this paper, we discuss whether accelerated testing methods alter the fundamental mechanisms of glass corrosion by comparing the alteration patterns that occur in naturally altered glasses with those that occur in accelerated laboratory environments. This comparison is done by (1) describing the alteration of glasses reacted in nature over long periods of time and in accelerated laboratory environments and (2) establishing the reaction kinetics of naturally altered glass and laboratory reacted glass waste forms.

Luo, J.S.; Wronkiewicz, D.J.; Mazer, J.J.; Bates, J.K.

1996-05-01

440

16 CFR 1610.3 - Summary of test method.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

441

16 CFR 1610.3 - Summary of test method.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

442

Alternative methods for eye and skin irritation tests: an overview.  

PubMed

The evaluation of eye and skin irritation potential is essential to ensuring the safety of individuals in contact with a wide variety of substances designed for industrial, pharmaceutical or cosmetic use. The Draize rabbit eye and skin irritancy tests have been used for 60 years to attempt to predict the human ocular and dermal irritation of such products. The Draize test has been the standard for ocular and dermal safety assessments for decades. However, several aspects of the test have been criticised. These include: the subjectivity of the method; the overestimation of human responses; and the method's cruelty. The inadequacies of the Draize test have led to several laboratories over the last 20 years making efforts to develop in vitro assays to replace it. Protocols that use different types of cell cultures and other methods have been devised to study eye and skin irritation. Different commercial kits have also been developed to study eye and skin irritation, based on the action of chemicals on these tissues. This article presents a review of the main alternatives developed to replace the use of animals in the study of chemical irritation. Particular attention is paid to the reproducibility of each method. PMID:17701961

Vinardell, M P; Mitjans, M

2008-01-01

443

Research Methods Knowledge Base : The t-Test  

NSDL National Science Digital Library

This particular textbook lesson, presented by Cornell University's Research Methods Knowledge Base, addresses the independent t-test. It presents to the user how to compute the t statistic and then how to interpret the results. The site uses graphs and charts along with the text to enhance the presentation. Overall, this is a useful resource for any mathematics classroom.

Trochim, William M.

2008-12-26

444

40 CFR 75.22 - Reference test methods.  

Code of Federal Regulations, 2010 CFR

...8.1 of the method or the moisture approximation procedure...accuracy test audits of continuous moisture monitoring systems are conducted...approximating the stack gas moisture content described in section...in Flue Gas Generated from Coal-Fired Stationary...

2010-07-01

445

ENVIRONMENTAL METHODS TESTING SITE PROJECT: PROJECT MANAGEMENT PLAN  

EPA Science Inventory

The Environmental Methods Testing Site Project is being conducted by the Environmental Protection Agency with the cooperation of the state of Georgia, the state of Tennessee, Hamilton County, Tennessee, and the city of Chattanooga. The concept is to establish one well-characteriz...

446

Laboratory methods for testing the performance of acoustic rail dampers  

E-print Network

Laboratory methods for testing the performance of acoustic rail dampers M. Towarda and D. J@soton.ac.uk Proceedings of the Acoustics 2012 Nantes Conference 23-27 April 2012, Nantes, France 3739 #12;Rail dampers with distance of vibration transmitted along the rail (decay rate). These dampers, attached to the rail between

Paris-Sud XI, Université de

447

Electrostatic and Piezoelectric Testing Methods for RF MEMS Resonators  

Microsoft Academic Search

Two techniques to characterize diamond micromechanical resonator structures are described: (1) electrostatic testing, and (2) piezoelectric actuation with optical detection. It is found that, while the resonant frequency values obtained from the two techniques differ only by 3%, method (2) yield up to eight times larger estimates for the quality factor Q. After describing the techniques and discussing experimental results,

N. Sepulveda; M. Toledo-Quinones

2006-01-01

448

Improving Dementia Screening Tests with Machine Learning Methods  

E-print Network

Improving Dementia Screening Tests with Machine Learning Methods William Rodman Shankle Department improve dementia screening. DSM-IV criteria for dementia were used to categorize patients into normal their accuracy in detecting cognitive impairment and dementia, and to implement their combined use in a simple

Pazzani, Michael J.

449

Improving Dementia Screening Tests with Machine Learning Methods  

E-print Network

Improving Dementia Screening Tests with Machine Learning Methods William Rodman Shankle Department improve dementia screening. DSM­IV criteria for dementia were used to categorize patients into normal their accuracy in detecting cognitive impairment and dementia, and to implement their combined use in a simple

Pazzani, Michael J.

450

40 CFR 63.365 - Test methods and procedures.  

Code of Federal Regulations, 2013 CFR

...analysis procedures in ASTM D 3695-88, Standard Test Method for Volatile Alcohols in Water By Direct Aqueous-Injection Gas Chromatography, (incorporated by reference—see § 63.14) shall be used to determine the ethylene glycol concentration. (2)...

2013-07-01

451

40 CFR 63.365 - Test methods and procedures.  

Code of Federal Regulations, 2012 CFR

...analysis procedures in ASTM D 3695-88, Standard Test Method for Volatile Alcohols in Water By Direct Aqueous-Injection Gas Chromatography, (incorporated by reference—see § 63.14) shall be used to determine the ethylene glycol concentration. (2)...

2012-07-01

452

Dissolution of cellulose in anhydrous chloral\\/aprotic solvents  

Microsoft Academic Search

Two new approaches toward the chemical modification and rapid dissolution of cellulose pulp in aprotic solvents containing chloral are presented. In the first method, cellulose pulp is water activated and then solvent exchanged prior to the addition of chloral. In the second method, cellulose pulp is heated in refluxing solvent and then cooled to ambient temperature before the addition of

Adel El-Kafrawy; Albin F. Turbak

1982-01-01

453

Comparison of the effect of chitosan and polyvinylpyrrolidone on dissolution properties and analgesic effect of naproxen  

Microsoft Academic Search

The solubilizing and absorption enhancer properties towards naproxen of chitosan and polyvinylpyrrolidone (PVP) have been investigated. Solid binary systems prepared at various drug–polymer ratios by mixing, cogrinding or kneading, were characterized by differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy, and scanning electron microscopy, and tested for dissolution behavior. Both carriers improved drug dissolution and their performance depended on

Naima Zerrouk; Natascia Mennini; Francesca Maestrelli; Chantal Chemtob; Paola Mura

2004-01-01

454

TRANSIENT ELECTRONICS Electronics technologies that can physically disappear by dissolution in water or biofluids  

E-print Network

TRANSIENT ELECTRONICS Electronics technologies that can physically disappear by dissolution dissolution products ZnO.[25] Metals with less comprehensive data on biocompatibility are also worthy at rates of 0.02­0.06 m h-1 in SBF at room temperature (RT).[26] In vivo tests of W embolisation coils

Rogers, John A.

455

In vitro dissolution of uranium oxide by baboon alveolar macrophages.  

PubMed Central

In vitro cellular dissolution tests for insoluble forms of uranium oxide are technically difficult with conventional methodology using adherent alveolar macrophages. The limited number of cells per flask and the slow dissolution rate in a large volume of nutritive medium are obvious restricting factors. Macrophages in suspension cannot be substituted because they represent different and poorly reproducible functional subtypes with regard to activation and enzyme secretion. Preliminary results on the dissolution of uranium oxide using immobilized alveolar macrophages are promising because large numbers of highly functional macrophages can be cultured in a limited volume. Cells were obtained by bronchoalveolar lavages performed on baboons (Papio papio) and then immobilized after the phagocytosis of uranium octoxide (U3O8) particles in alginate beads linked with Ca2+. The dissolution rate expressed as percentage of initial uranium content in cells was 0.039 +/- 0.016%/day for particles with a count median geometric diameter of 3.84 microns(sigma g = 1.84). A 2-fold increase in the dissolution rate was observed when the same number of particles was immobilized without macrophages. These results, obtained in vitro, suggest that the U3O8 preparation investigated should be assigned to inhalation class Y as recommended by the International Commission on Radiological Protection. Future experiments are intended to clarify this preliminary work and to examine the dissolution characteristics of other particles such as uranium dioxide. It is recommended that the dissolution rate should be measured over an interval of 3 weeks, which is compatible with the survival time of immobilized cells in culture and may reveal transformation states occurring with aging of the particles. PMID:1396447

Poncy, J L; Metivier, H; Dhilly, M; Verry, M; Masse, R

1992-01-01

456

In vitro dissolution of uranium oxide by baboon alveolar macrophages  

SciTech Connect

In vitro cellular dissolution tests for insoluble forms of uranium oxide are technically difficult with conventional methodology using adherent alveolar macrophages. The limited number of cells per flask and the slow dissolution rate in a large volume of nutritive medium are obvious restricting factors. macrophages in suspension cannot be substituted because they represent different and poorly reproducible functional subtypes with regard to activation and enzyme secretion. Preliminary results on the dissolution of uranium oxide using immobilized alveolar macrophages are promising because large numbers of highly function macrophages can be cultured in a limited volume. Cells were obtained by bronchoalveolar lavages performed on baboons (Papio papio) and then immobilized after the phagocytosis of uranium octoxide (U[sub 3]O[sub 8]) particles in alginate beads linked with Ca[sup 2+]. The dissolution rate expressed as percentage of initial uranium content in cells was 0.039 [+-] 0.016%/day for particles with a count median geometric diameter of 3.84 [mu]m([sigma][sub g] = 1.84). A 2-fold increase in the dissolution rate was observed when the same number of particles was immobilized without macrophages. These results, obtained in vitro, suggest that the U[sub 3]O[sub g] preparation investigated should be assigned to inhalation class Y as recommended by the International Commission on Radiological Protection. Future experiments are intended to clarify this preliminary work and to examine the dissolution characteristics of other particles such as uranium dioxide. It is recommended that the dissolution rate should be measured over an interval of 3 weeks, which is compatible with the survival time of immobilized cells in culture and may reveal transformation states occurring with aging of the particles. 23 refs., 3 figs.

Poncy, J.L.; Dhilly, M.; Verry, M. (CEA/DSV/DPTE/LRT, Bruyeres le Chatel (France)); Metivier, H. (CEA/IPSN/DRSN, Fontenay aux Roses (France)); Masse, R. (CEA/DSV/DPTE, Fontenay aux Roses (France))

1992-07-01

457

Controlled evaluation of silver nanoparticle dissolution using atomic force microscopy.  

PubMed

Incorporation of silver nanoparticles (AgNPs) into an increasing number of consumer products has led to concern over the potential ecological impacts of their unintended release to the environment. Dissolution is an important environmental transformation that affects the form and concentration of AgNPs in natural waters; however, studies on AgNP dissolution kinetics are complicated by nanoparticle aggregation. Herein, nanosphere lithography (NSL) was used to fabricate uniform arrays of AgNPs immobilized on glass substrates. Nanoparticle immobilization enabled controlled evaluation of AgNP dissolution in an air-saturated phosphate buffer (pH 7.0, 25 °C) under variable NaCl concentrations in the absence of aggregation. Atomic force microscopy (AFM) was used to monitor changes in particle morphology and dissolution. Over the first day of exposure to ?10 mM NaCl, the in-plane AgNP shape changed from triangular to circular, the sidewalls steepened, the in-plane radius decreased by 5-11 nm, and the height increased by 6-12 nm. Subsequently, particle height and in-plane radius decreased at a constant rate over a 2-week period. Dissolution rates varied linearly from 0.4 to 2.2 nm/d over the 10-550 mM NaCl concentration range tested. NaCl-catalyzed dissolution of AgNPs may play an important role in AgNP fate in saline waters and biological media. This study demonstrates the utility of NSL and AFM for the direct investigation of unaggregated AgNP dissolution. PMID:22191460

Kent, Ronald D; Vikesland, Peter J

2012-07-01

458

Method and device for spin-testing of turbocharger rotor  

SciTech Connect

This patent describes a method for spin-testing a turbocharger rotor. The rotor includes a shaft portion which is fixed to an assembly of component parts which include a thrust bearing, a spacer, at least one of a sleeve portion and compressor rotor portion, and a lock nut. The improvement comprises: preparing an integral composite member consisting of at least two of the component parts; dynamically balancing the turbocharger rotor, without the shaft portion fixed to the assembly; placing the turbocharger rotor and the integral composite member in a testing device, such that the shaft portion and the assembly are fixed to each other by the lock nut, and are rotatable as a unit; and rotating the turbocharger rotor and the assembly in the testing device, to effect the spin-testing.

Kawasaki, K.

1987-09-22

459

Mode-Stirred Method Implementation for HIRF Susceptibility Testing and Results Comparison with Anechoic Method  

NASA Technical Reports Server (NTRS)

This paper describes the implementation of mode-stirred method for susceptibility testing according to the current DO-160D standard. Test results on an Engine Data Processor using the implemented procedure and the comparisons with the standard anechoic test results are presented. The comparison experimentally shows that the susceptibility thresholds found in mode-stirred method are consistently higher than anechoic. This is consistent with the recent statistical analysis finding by NIST that the current calibration procedure overstates field strength by a fixed amount. Once the test results are adjusted for this value, the comparisons with the anechoic results are excellent. The results also show that test method has excellent chamber to chamber repeatability. Several areas for improvements to the current procedure are also identified and implemented.

Nguyen, Truong X.; Ely, Jay J.; Koppen, Sandra V.

2001-01-01

460

Dissolution rate of limestone for wet flue gas desulfurization in the presence of sulfite.  

PubMed

Limestone dissolution rate was measured by a pH-stat method with CO(2) sparging and dissolved sulfite. The dissolution rate of limestone under these conditions was found to be controlled by mass transfer and surface kinetics. As can be seen from the results, in the presence of sulfite, limestone dissolution rate increases with increasing stirring speed, reaction temperature and CO(2) partial pressure. The crystallinity of limestone has a great impact on the dissolution rate: The lower the value of the crystallinity of limestone is, the higher the dissolution rate is. The presence of sulfite promotes the dissolution rate when pH value is below 5.5 but inhibits it when pH value is above 5.5. PMID:19359093

Xiang, Gao; Rui-tang, Guo; Hong-lei, Ding; Zhong-yang, Luo; Ke-fa, Cen

2009-09-15

461

Dissolution and permeation properties of naproxen from solid-state systems with chitosan.  

PubMed

The purpose of this study was to investigate the influence of different types of chitosan and of the preparation technique of the drug-polymer combination in improving the dissolution and permeation abilities of naproxen, a very poorly water-soluble anti-inflammatory drug. Drug-chitosan systems were prepared by simple physical mixing, kneading, cogrinding, or coevaporation using five types of chitosan (base and glutamate or hydrochloride salts, both at two different molecular weights). The products were tested for drug-dissolution behavior and for permeation properties through both Caco-2 cell monolayers and artificial lipophilic membranes. All combinations with chitosan base were significantly (p < .01) more effective in enhancing drug-dissolution rate than those with both its salts, probably in virtue of its higher amorphizing effect toward the drug, as observed in solid-state studies. A different rank order was found in permeation experiments in which chitosan glutamate was the most powerful partner in improving the drug-apparent permeability (p < .01), followed by the hydrochloride salt (p < .05), whereas no significant effect was obtained with chitosan base. Cogrinding was the most powerful technique in promoting both dissolution and permeation properties of the drug, thus pointing out the importance of the preparation method in obtaining efficacious drug-carrier systems. Finally, the good correspondence between permeation experiments with Caco-2 cells and those with the artificial lipophilic membrane indicated the suitability of this latter in preformulation studies for a rapid screening of the best carrier and the most efficient drug-carrier preparation method for improving the biopharmaceutical properties of drugs. PMID:18763161

Corti, Giovanna; Maestrelli, Francesca; Cirri, Marzia; Mura, Paola; Zerrouk, Naima

2008-06-01

462

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

PubMed

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. Results show that the number of faults above the lower aquifer that contains the salt layer is considered as the most important factor that affects the dissolution compared to the other investigated parameters of thickness of the zone above the halite formation, a dynamic conductivity of the lower aquifer, and varying boundary conditions in the upper aquifer. PMID:24650646

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

2014-05-01

463

[Clinical application of testing methods on acid-fast bacteria].  

PubMed

Clinical bacteriology pertaining to acid-fast bacteria has made marked advances over the past decade, initiated by the development of a DNA probe kit for identification of acid-fast bacteria. Wide-spread use of nucleic acid amplification for rapid detection of tubercle bacillus contributed more greatly than any other factor to such advances in this field. At present, 90% of all kits used for nucleic acid amplification in the world are consumed in Japan. Unfortunately, not a few clinicians in Japan have a false idea that the smear method and nucleic acid amplification are necessary but culture is not. In any event nucleic acid amplification has exerted significant impacts on the routine works at bacteriology laboratories. Among others, collecting bacteria by pretreatment with NALC-NaOH has simplified the introduction of the collective mode smear method and liquid media. Furthermore, as clinicians have become increasingly more experienced with various methods of molecular biology, it now seems possible to apply these techniques for detection of genes encoding drug resistance and for utilization of molecular epidemiology in routine laboratory works. Meanwhile, attempts to diagnose acid-fast bacteriosis by checking blood for antibody have also been made, primarily in Japan. At present, two kits for detecting antibodies to glycolipids (LAM, TDM, etc.) are covered by national health insurance in Japan. We have an impression that in Japan clinicians do not have adequate knowledge and skill to make full use of these new testing methods clinically. We, as the chairmen of this symposium, hope that this symposium will help clinicians increase their skill related to new testing methods, eventually leading to stimulation of advances in clinical practices related to acid-fast bacteria in Japan. 1. Smear microscopy by concentration method and broth culture system: Kazunari TSUYUGUCHI (Clinical Research Center, National Hospital Organization Kinki-chuo Chest Medical Center) Smear microscopy and culture still remain the cornerstone to diagnose tuberculosis. However, the classical methods in Japan using direct microscopy and Ogawa solid media were not sufficient for clinical use. In recent years substantial advance has been made in these fields. Concentration of clinical samples by centrifugation improves the sensitivity of smear microscopy with excellent reproducibility. The Mycobacteria Growth Indicator Tube (MGIT) system using liquid media yields high sensitivity and rapidity. Using these methods, more and more tuberculosis cases would be correctly diagnosed and treated adequately based on drug susceptibility testing. 2. New technologies for anti-tuberculosis drug susceptibility testing: Satoshi MITARAI (Bacteriology Division, Reference Centre for Mycobacterium, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association) Several new technologies have been developed to obtain anti-tuberculosis drug susceptibility testing (AST) results rapidly, utilising liquid culture and molecular technologies. Mycobacterium Growth Indicator Tube (MGIT), as a popular liquid culturing and AST system, was evaluated for its accuracy and usefulness. As for isoniazid, MGIT showed 12.6% of discordant result comparing with standard method. These MGIT resistant and Ogawa susceptible strains had relatively high MICs ranging 0.13 to 2.0 microg/ml. The molecular detection of resistant gene mutation is also a useful method to estimate drug resistance rapidly. The rpoB mutation detection is reliable with high sensitivity and specificity. 3. Nucleic acid amplification and novel diagnostic methods: Shunji TAKAKURA (Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine) Sensitivities of nucleic acid amplification tests (NAATs) for the diagnosis of tuberculosis meet clinical requirement that patients with high-risk of transmission should be identified within a day. Comparison of the performance of various NAATs is difficult because of the difference in sample processing and in samples tested among methods and reports. Con

Ichiyama, Satoshi; Suzuki, Katsuhiro

2005-02-01

464

Adolescent Sexuality and the Risk of Marital Dissolution  

ERIC Educational Resources Information Center

This research investigates whether first sexual intercourse during adolescence is associated with increased risk of first marriage dissolution and tests whether the results are consistent with causal or selection explanations. Drawing on a sample of 3,793 ever-married women from the 2002 National Survey of Family Growth, this study estimated…

Paik, Anthony

2011-01-01

465

Premarital Cohabitation and Marital Dissolution: An Examination of Recent Marriages  

ERIC Educational Resources Information Center

An ongoing question remains for family researchers: Why does a positive association between cohabitation and marital dissolution exist when one of the primary reasons to cohabit is to test relationship compatibility? Drawing on recently collected data from the 2006-2008 National Survey of Family Growth, the authors examined whether premarital…

Manning, Wendy D.; Cohen, Jessica A.

2012-01-01

466

Dissolution of materials in artificial skin surface film liquids  

Microsoft Academic Search

The dissolution of chemical constituents from jewelry, textiles, cosmetics, drugs, industrial chemicals, and particles in direct and prolonged contact with human skin is often assessed in vitro using artificial skin surface film liquids (SSFL). To provide meaningful results, the composition of artificial SSFL should accurately mimic human sweat and sebum, and the conditions of the in vitro test system should

Aleksandr B. Stefaniak; Christopher J. Harvey

2006-01-01

467

Method of and apparatus for testing the integrity of filters  

DOEpatents

A method of and apparatus are disclosed for testing the integrity of individual filters or filter stages of a multistage filtering system including a diffuser permanently mounted upstream and/or downstream of the filter stage to be tested for generating pressure differentials to create sufficient turbulence for uniformly dispersing trace agent particles within the airstream upstream and downstream of such filter stage. Samples of the particle concentration are taken upstream and downstream of the filter stage for comparison to determine the extent of particle leakage past the filter stage. 5 figs.

Herman, R.L.

1985-05-07

468

Value of information methods for assessing a new diagnostic test.  

PubMed

Value-of-information methods are applied to assess the evidence in support of a new diagnostic test and, where the evidence is insufficient for decision making, to determine the optimal sample size for future studies. Net benefit formulations are derived under various diagnostic and treatment scenarios. The expressions for the expected opportunity loss of adopting strategies that include the new test are given. Expressions for the expected value of information from future studies are derived. One-sample and two-sample designs, with or without known prevalence, are considered. An example is given. PMID:24403241

Chen, Maggie Hong; Willan, Andrew R

2014-05-20

469

CPV solar receiver ageing tests: The enhanced electroluminescence method  

NASA Astrophysics Data System (ADS)

For two years now, CEA INES is involved in the development of insulated metal substrates (IMS) for CPV receivers. In an effort for establishing the reliability of such a new design compared to state-of-the-art direct bonded copper (DBC) design, accelerated ageing test have been carried out. During these tests, several characterization tools were used including current voltage measurements, X-ray tomography and electroluminescence. A new method for the characterization of thermal inhomogeneities has been developed, the so-called Enhanced Electroluminescence (EEL) which is described in this paper.

Mabille, Loïc; Mangeant, Christophe; Baudrit, Mathieu

2013-09-01

470

Cartridge output testing - Methods to overcome closed-bomb shortcomings  

NASA Technical Reports Server (NTRS)

Although the closed-bomb test has achieved virtually universal acceptance for measuring the output performance of pyrotechnic cartridges, there are serious shortcomings in its ability to quantify the performance of cartridges used as energy sources for pyrotechnic-activated mechanical devices. This paper presents several examples of cartridges (including the NASA Standard Initiator NSI) that successfully met closed-bomb performance requirements, but resulted in functional failures in mechanisms. To resolve these failures, test methods were developed to demonstrate a functional margin, based on comparing energy required to accomplish the function to energy deliverable by the cartridge.

Bement, Laurence J.; Schimmel, Morry L.

1991-01-01

471

Fracture Test Methods for Plastically Responding COPV Liners  

NASA Technical Reports Server (NTRS)

An experimental procedure for evaluating the validity of using uniaxial tests to provide a conservative bound on the fatigue crack growth rate behavior small cracks in bi-axially loaded Composite Overwrapped Pressure Vessel (COPV) liners is described. The experimental procedure included the use of a laser notch to quickly generate small surface fatigue cracks with the desired size and aspect ratios. An out-of-plane constraint system was designed to allow fully reversed, fully plastic testing of thin sheet uniaxial coupons. Finally, a method was developed to determine to initiate small cracks in the liner of COPVs.

Dawicke, David S.; Lewis, Joseph C.

2009-01-01

472

Well test imaging - a new method for determination of boundaries from well test data  

SciTech Connect

A new method has been developed for analysis of well test data, which allows the direct calculation of the location of arbitrary reservoir boundaries which are detected during a well test. The method is based on elements of ray tracing and information theory, and is centered on the calculation of an instantaneous {open_quote}angle of view{close_quote} of the reservoir boundaries. In the absence of other information, the relative reservoir shape and boundary distances are retrievable in the form of a Diagnostic Image. If other reservoir information, such as 3-D seismic, is available; the full shape and orientation of arbitrary (non-straight line or circular arc) boundaries can be determined in the form of a Reservoir Image. The well test imaging method can be used to greatly enhance the information available from well tests and other geological data, and provides a method to integrate data from multiple disciplines to improve reservoir characterization. This paper covers the derivation of the analytical technique of well test imaging and shows examples of application of the technique to a number of reservoirs.

Slevinsky, B.A.

1997-08-01

473

Standard methods for open hole tension testing of textile composites  

NASA Technical Reports Server (NTRS)

Sizing effects have been investigated by comparing the open hole failure strengths of each of the four different braided architectures as a function of specimen thickness, hole diameter, and the ratio of specimen width to hole diameter. The data used to make these comparisons was primarily generated by Boeing. Direct comparisons of Boeing's results were made with experiments conducted at West Virginia University whenever possible. Indirect comparisons were made with test results for other 2-D braids and 3-D weaves tested by Boeing and Lockheed. In general, failure strength was found to decrease with increasing plate thickness, increase with decreasing hole size, and decreasing with decreasing width to diameter ratio. The interpretation of the sensitive to each of these geometrical parameters was complicated by scatter in the test data. For open hole tension testing of textile composites, the use of standard testing practices employed by industry, such as ASTM D5766 - Standard Test Method for Open Hole Tensile Strength of Polymer Matrix Composite Laminates should provide adequate results for material comparisons studies.

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

1995-01-01

474

Standard test method for measuring pH of soil for use in corrosion testing  

E-print Network

1.1 This test method covers a procedure for determining the pH of a soil in corrosion testing. The principle use of the test is to supplement soil resistivity measurements and thereby identify conditions under which the corrosion of metals in soil may be accentuated (see G 57 - 78 (1984)). 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

American Society for Testing and Materials. Philadelphia

1995-01-01

475

Dissolution Kinetics of Alumina Calcine  

SciTech Connect

Dissolution kinetics of alumina type non-radioactive calcine was investigated as part of ongoing research that addresses permanent disposal of Idaho High Level Waste (HLW). Calcine waste was produced from the processing of nuclear fuel at the Idaho Nuclear Technology and Engineering Center (INTEC). Acidic radioactive raffinates were solidified at ~500°C in a fluidized bed reactor to form the dry granular calcine material. Several Waste Management alternatives for the calcine are presented in the Idaho High Level Waste Draft EIS. The Separations Alternative addresses the processing of the calcine so that the HLW is ready for removal to a national geological repository by the year 2035. Calcine dissolution is the key front-end unit operation for the separations alternative.

Batcheller, Thomas Aquinas

2001-09-01

476

Study of Accurate High-Speed Tension Testing Method  

NASA Astrophysics Data System (ADS)

The high measurement accuracy in dynamic tension testing is required for designs and numerical simulations based on the accurate modeling of stress-strain relations at various strain-rates. The non-coaxial Hopkinson bar method (NCHBM) is one of the recently proposed methods for dynamic tension tests. In this study, the direct measurement of both stress and strain was conducted by using the strain gauges affixed on the special specimen with load cell part. The stress-strain relations obtained by this revised NCHBM were compared with those obtained by the normal NCHBM. In order to verify the experimental results, some numerical models were examined by using the FEM code LS-DYNA, in which the whole finite-element model of the apparatus and the plate-type specimen were made in detail. Furthermore, new appliances for fixing specimen were examined by experiment. The target material employed in this study is SUS316.

Umeda, Tsutomu; Mimura, Koji

477

Cost-effective test methods for Shuttle payloads  

NASA Technical Reports Server (NTRS)

Techniques are discussed for deriving constrained vibration mode shapes for Space Shuttle payloads using unconstrained or free-boundary dynamic properties. Application of the residual flexibility method requires measurement of a set of free-boundary modes plus the residual flexibility of the payload-to-orbiter interfaces. The mass-additive approach involves the measurement of unconstrained modes and frequencies of a payload with large masses attached to the interfaces. In either case, the orbiter interfaces of the test-verified payload model are analytically constrained to provide the mode shapes for the Shuttle-constrained configuration. Use of these methods or a hybrid combination of them for structures to which they are applicable allows the difficult and expense associated with development and verification of fixed-base test fixtures to be avoided.

Tinker, Michael L.

1993-01-01

478