The Effect of VikaneTm on the Stability of Cellulosic and Ligneous Materials -- Measurement of Deterioration by Chemical and Physical Methods

1990 ◽  
Vol 185 ◽  
Author(s):  
Helen D. Burgess ◽  
Nancy E. Binnie
Keyword(s):  
Hydrolytic Degradation ◽  
Degree Of Polymerization ◽  
Accelerated Ageing ◽  
Total Acid ◽  
Long Term Stability ◽  
Before And After ◽  
Pulp Fibres ◽  
General Scientific ◽  
The Stability

AbstractVikaneTM (sulphuryl fluoride) is a commercial fumigant[1] which is used for the control of pests in museum collections. This paper summarizes the results obtained through an investigation of the effect of VikaneTM on twenty-five paper and textile samples. Samples chosen were representative of artifacts present in North American collections (cotton, linen, jute, and wood pulp fibres, from 1622 to present).The effect of the fumigation treatment has been evaluated by chemical and physical analyses: (1) Acidity -- surface pH, cold extracted pH, total acid (iodometric titration), (2) Oxidative and Hydrolytic Degradation - viscometric average degree of polymerization, carbonyl content (hydrazone derivatization), (3) and Fumigant Residues (specific ion electrode). Analysis of unfumigated and fumigated samples was carried out before and after accelerated ageing (70°C and 50% relative humidity) in order to estimate the long term stability of fumigated samples.The data obtained show that commercial grade VikaneTM degrades cellulosic and ligneous fibres. A second set of experiments on two fibre types using a new experimental grade of VikaneTM gave significantly less degradation. The presentation of this work will concentrate upon a general scientific interpretation of results.It is anticipated that the conclusions will be applicable to a broad range of artifacts.

Suitability of Flash Media for the Long-Term Storage of Information

2019 ◽  
Vol 40 (2) ◽  
pp. 97-122
Author(s):  
Joe Iraci
Keyword(s):  
High Capacity ◽  
Accelerated Ageing ◽  
Flash Storage ◽  
Long Term Stability ◽  
Long Term Storage ◽  
Storage Media ◽  
The Stability ◽  
To Receive ◽  
Term Storage

Abstract Flash storage media such as memory cards and USB flash drives are now commonly used to transfer and store information. However, little is known about the long-term stability of this type of media and this is a concern for archives and other institutions as they begin to receive content stored on these devices. In this study, the stabilities of a variety of different flash media were examined. The evaluation was performed by using accelerated ageing at 85 °C and 85 % relative humidity (RH) and 125 °C for ageing intervals up to 2000 hours. Measurements were also performed on samples previously subjected to accelerated ageing and then naturally aged for five years to verify the results from the accelerated ageing experiments. Overall, the stability of flash media was very good. For many of the samples, no read errors were encountered after accelerated or natural ageing. However, for several of the high capacity flash card samples and USB flash drives, significant decreases in read speed were noted. This can be problematic because it will eventually lead to read errors. It was established that for the USB samples this instability was likely attributed to the use of the less stable TLC (triple-level cell) memory chip.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

scholarly journals Limitations and Challenges in the Stability of Cysteamine Eye Drop Compounded Formulations

2021 ◽  
Vol 15 (1) ◽  
pp. 2
Author(s):  
Cristina Martín-Sabroso ◽  
Mario Alonso-González ◽  
Ana Fernández-Carballido ◽  
Juan Aparicio-Blanco ◽  
Damián Córdoba-Díaz ◽  
...  
Keyword(s):  
Shelf Life ◽  
Stability Study ◽  
Eye Drops ◽  
Microbiological Analysis ◽  
Nitrogen Gas ◽  
Long Term Stability ◽  
Main Degradation Product ◽  
The Stability ◽  
Unstable Molecule

Accumulation of cystine crystals in the cornea of patients suffering from cystinosis is considered pathognomonic and can lead to severe ocular complications. Cysteamine eye drop compounded formulations, commonly prepared by hospital pharmacy services, are meant to diminish the build-up of corneal cystine crystals. The objective of this work was to analyze whether the shelf life proposed for six formulations prepared following different protocols used in hospital pharmacies is adequate to guarantee the quality and efficacy of cysteamine eye drops. The long-term and in-use stabilities of these preparations were studied using different parameters: content of cysteamine and its main degradation product cystamine; appearance, color and odor; pH and viscosity; and microbiological analysis. The results obtained show that degradation of cysteamine was between 20% and 50% after one month of storage in the long-term stability study and between 35% and 60% in the in-use study. These data confirm that cysteamine is a very unstable molecule in aqueous solution, the presence of oxygen being the main degradation factor. Saturation with nitrogen gas of the solutions offers a means of reducing cysteamine degradation. Overall, all the formulae studied presented high instability at the end of their shelf life, suggesting that their clinical efficacy might be dramatically compromised.

Numerical Simulation on Deformation Features and Filling Efficiency of Channel Goaf Foundation

2013 ◽  
Vol 353-356 ◽  
pp. 3707-3712
Author(s):  
Zhi Dong Zhou ◽  
Hong Bo Zhang ◽  
Xiu Guang Song ◽  
Hong Ya Yue
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Comprehensive Analysis ◽  
Obvious Effect ◽  
Before And After ◽  
Check Gate ◽  
Deformation Features ◽  
Natural Foundation ◽  
The Stability

For analyzing and evaluating the deformation features of channel goaf foundation and its effect on superstructure, according to the foundation reinforcement engineering of Ji-Liang Channel Check Gate, the comparative analysis on the differential settlement between the unfavorable foundation and natural foundation was performed by numerical simulation with FLAC3D. The computer results showed that the present foundation had obvious effect on the stability and security of the superstructure, so the engineering treatment are needed. Based on technical-economic comprehensive analysis among three treatment methods for strengthening the channel golf foundation with different kinds of filling, the reasonable method is put forward in this paper. By comparing mechanical characteristic of flashboard in channel goaf before and after strengthening, we confirmed the foundation stability of channel goaf and the security of the ground building which can satisfy the long term usage requirements.

LONG-TERM STABILITY ANALYSIS OF ACOUSTIC ABSORBING BOUNDARY CONDITIONS

2013 ◽  
Vol 23 (11) ◽  
pp. 2129-2154 ◽  
Author(s):  
HÉLÈNE BARUCQ ◽  
JULIEN DIAZ ◽  
VÉRONIQUE DUPRAT
Keyword(s):  
Stability Analysis ◽  
Boundary Conditions ◽  
Absorbing Boundary Conditions ◽  
Computational Domain ◽  
Acoustic Wave Equation ◽  
Absorbing Boundary ◽  
Term Stability ◽  
Long Term Stability ◽  
The Stability

This work deals with the stability analysis of a one-parameter family of Absorbing Boundary Conditions (ABC) that have been derived for the acoustic wave equation. We tackle the problem of long-term stability of the wave field both at the continuous and the numerical levels. We first define a function of energy and show that it is decreasing in time. Its discrete form is also decreasing under a Courant–Friedrichs–Lewy (CFL) condition that does not depend on the ABC. Moreover, the decay rate of the continuous energy can be determined: it is exponential if the computational domain is star-shaped and this property can be illustrated numerically.

A Review of Preparation and Tribological Applications of Pickering Emulsion

2021 ◽  
pp. 1-27
Author(s):  
Yichen Bao ◽  
Kai Liu ◽  
Quan Zheng ◽  
Lulu Yao ◽  
Yufu Xu
Keyword(s):  
Pickering Emulsion ◽  
Solid Particles ◽  
Preparation Methods ◽  
Factors Affecting ◽  
Long Term Stability ◽  
New Strategy ◽  
New Type ◽  
The Stability ◽  
Near Future

Abstract Pickering emulsion is a new type of stable emulsion made by ultra-fine solid particles instead of traditional surfactants as stabilizers, which has received widespread attention in recent years. The preparation methods of stator-rotor homogenization, high-pressure homogenization, and ultrasonic emulsification were compared with others in this work. The main factors affecting the stability of Pickering emulsion are the surface humidity of the solid particles, the polarity of the oil phase, and the oil-water ratio. These factors could affect the nature of the solid particles, the preparation process of Pickering emulsion and the external environment. Consequently, the long-term stability of Pickering emulsion is still a challenge. The tribological investigations of Pickering emulsion were summarized, and the multifunctional Pickering emulsion shows superior prospects for tribological applications. Moreover, the latest development of Pickering emulsion offers a new strategy for smart lubrication in the near future.

Stability of a Piezoresistive Ceramic Pressure Sensor Made With LTCC Technology

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000371-000376 ◽  
Author(s):  
Marina Santo Zarnik ◽  
Darko Belavic
Keyword(s):  
Pressure Sensor ◽  
Fatigue Testing ◽  
Low Pressure ◽  
Fatigue Tests ◽  
Point Of View ◽  
Long Term Stability ◽  
Pressure Cycling ◽  
Key Characteristics ◽  
The Stability

This paper discusses the stability of a piezoresistive, LTCC-based, pressure sensor that was designed for measurements in a low-pressure range below 100 mbar. The intrinsic stability of the sensor's offset was evaluated at a constant ambient temperature and different conditions regarding the atmospheric humidity. The sensors were also subjected to functional fatigue tests, which included a full-scale and an overload pressure cycling. The results of the fatigue testing revealed the vulnerability of the sensor's structure from the point of view of the long-term stability and the life-cycle. Nevertheless, the stability of the key characteristics of the prototype sensors was found to be satisfactory for accurate measurements in the low-pressure ranges.

Fabrication of Boron Compensated Hydrogenated Amorphous Silicon Films with Significantly Improved Stability Using Plasma Enhanced Chemical Vapor Deposition Technique

1995 ◽  
Vol 377 ◽  
Author(s):  
Mohan K. Bhan
Keyword(s):  
Chemical Vapor ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Vapor Deposition Technique ◽  
Improved Stability ◽  
Donor Acceptor ◽  
B Doping ◽  
The Stability

ABSTRACTWe have systematically investigated the effects of addition of sub-ppm levels of boron on the stability of a-Si:H films and p-i-n devices, deposited by PE-CVD technique. The films thus produced with appropriate amounts of boron, show a significant improvement in stability, when soaked under both AM 1.5 (short-term) as well as 10×sun (long-term) illumination conditions. The opto-electronic properties of the films are quite respectable It is concluded that boron compensates the native impurities by forming donor-acceptor pairs, which reduces the “fast” defects and hence the initial degradation of the films. It is also speculated that boron may also be improving the short-term stability, by reducing the recombination of light generated electrons and holes, by converting D° into D+ states. The long-term stability appears to get affected by hydrogen dilution which seems to reduce the amount of “slow” defects. As a result of B doping of i-layer, the initial conversion efficiency of the devices decreases. It is presumed that our devices may contain an enhanced level of boron impurity, than expected, making them as worse material and to degrade less.

scholarly journals Evaluation of long-term stability of mesiodistal axial inclinations of maxillary molars through panoramic radiographs in subjects treated with Pendulum appliance

2016 ◽  
Vol 21 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Caroline Andrade Rocha ◽  
Renato Rodrigues de Almeida ◽  
José Fernando Castanha Henriques ◽  
Carlos Flores-Mir ◽  
Marcio Rodrigues de Almeida
Keyword(s):  
Panoramic Radiograph ◽  
Post Treatment ◽  
Control Group ◽  
Long Term Stability ◽  
Maxillary Molars ◽  
Group Data ◽  
Maxillary Molar ◽  
Pendulum Appliance ◽  
The Stability

Objective: To evaluate the stability of mesiodistal inclination of maxillary molars produced by a pendulum appliance, five years after completion of orthodontic treatment. Angulation changes were compared to an untreated sample. Methods: The sample consisted of 20 patients (14 females and 6 males) with Class II, Division 1 malocclusion that was treated through molar distalization with a pendulum appliance followed by cervical headgear and full fixed appliances. Maxillary molar inclination was evaluated through panoramic radiograph. The mean age at pretreatment was 14.3 ± 1.6 years, whereas at immediate post-treatment it was 18.6 ± 1.8 years, and at long-term post-treatment it was 23.8 ± 2.0 years. A control group of 16 untreated individuals with untreated normocclusion ranging in age from 12 to 17 years old were used as comparison group. Data were statistically analyzed with independent t-tests and ANOVA test followed by Tukey post-hoc tests. Results: Statistically significant differences were found between T1 (94.50) and T2 (98.80) as well as between T2 and T3 (94.70) for maxillary first molars. Maxillary second molars did not show any statistically significant positional changes during the evaluated time periods T1 (107.50), T2 (109.30) and T3 (106.90). Conclusion: Although maxillary first molars underwent distal crown inclination immediately after treatment, approximately five years thereafter their roots tended to upright close to the pretreatment positions.

scholarly journals Long-Term Stability Comparison between an Original and a Generic Version of Piperacillin/Tazobactam in Dextrose 5 % Infusion Polyolefin Bags at 5 ± 3 °C after Microwave Freeze-Thaw Treatment

2018 ◽  
Vol 3 (3) ◽  
pp. 143-151
Author(s):  
Sophie Huvelle ◽  
Marie Godet ◽  
Laurence Galanti ◽  
Mélanie Closset ◽  
Benoît Bihin ◽  
...  
Keyword(s):  
Generic Version ◽  
Generic Product ◽  
Brand Name ◽  
Term Stability ◽  
Long Term Stability ◽  
Ph Values ◽  
Lower Confidence ◽  
The Stability ◽  
Aseptic Conditions

AbstractBackgroundPiperacillin-Tazobactam is frequently infused in hospitals. The use of a generic version was considered after the out of stock of the brand name Tazocin®. The stability of 4 g of Tazocin®in 120 mL of dextrose 5 % (D5) was demonstrated during 35 days at 5 °C ± 3 °C after freezing (−20 °C) and microwave thawing (FMT). The aim of the study was to investigate and compare the long-term stability of Tazocin®and a generic product in the same conditions.MethodsFive polyolefin bags of 4 g of Piperacillin/Tazobactam®Sandoz and 5 bags of 4 g of Tazocin®were prepared under aseptic conditions in 120 mL of D5 and stored 3 months at 20 °C then thawed and stored 58 days at 5 ± 3 °C.Spectrophotometric absorbance at different wavelengths, pH measurement, visual and microscopic observations were also performed.The concentrations were measured by HPLC, at 211 nm for tazobactam and 230 nm for piperacilline.ResultsNo significant change in pH values or optic densities, no crystals were detected. The lower confidence limit at 95 % of the concentration for the solutions remains superior to 90 % of the initial concentration until 58 days of storage at 5 ± 3 °C.ConclusionUnder these conditions, 4 g/120 mL of Piperacillin/Tazobactam®Sandoz or Tazocin®in D5 infusion in polyolefin bags remains stable at least for 58 days at 5 ± 3 °C after FMT

Sign in / Sign up

Export Citation Format

Share Document