Cure rate, factors

Microwave Fast curing rates (factor of 10) over forced convection heating. Reduced stress from CTE mismatched materials Cure schedules require optimization of many parameters. Specialized equipment... 

The choice of coagulant for breaking of the emulsion at the start of the finishing process is dependent on many factors. Salts such as calcium chloride, aluminum sulfate, and sodium chloride are often used. Frequentiy, pH and temperature must be controlled to ensure efficient coagulation. The objectives are to leave no uncoagulated latex, to produce a cmmb that can easily be dewatered, to avoid fines that could be lost, and to control the residual materials left in the product so that damage to properties is kept at a minimum. For example, if a significant amount of a hydrophilic emulsifier residue is left in the polymer, water resistance of final product suffers, and if the residue left is acidic in nature, it usually contributes to slow cure rate. 

Compound processibiUty is a key factor in the optimiza tion of new polychloroprene types. As a result, commercial compounds can be mixed, shaped, and cured by virtually all the methods used in the mbber industry. A typical polychloroprene compound includes a variety of additives designed to improve compound rheology, cure rate, and vulcanizate properties. 

The Effect of Crosslinker Concentration on the Rate of Polymerization. Ethylene glycol dimethacrylate is used most frequently as the crosslinker for HEMA formulations useful in contact lens manufacturing. To demonstrate the effect of crosslinker concentration on the curing rate, formulations derived from HEMA/Glycerine/BME at 85/15/0.17, while varying EGDMA (from 0.34 to 0.68), the peak times were about the same (3.73 and 3.61 minutes respectively). This is reasonable due to the similarity in molecular structure of the crosslinker and the monomer, and the low amount of crosslinker used. The possible presence of other crosslinker, such as the dimerization product of HEMA, is even less a factor to be considered in polymerization kinetics, due to low concentration (normally much less than 0.1 %, in-house information). 

This pediatric cancer stands as an example of how cooperative group studies (NWTS and SIOP) have been able to integrate both chemotherapy and radiation into standard therapy while minimizing side-effects and dramatically improving cure rates as seen in the improvement of the 5-yr relative survival rates from 74% in 1974-1976 to 93% in 1989-1996 (60). The fifth NWTS trial began in 1995 and is expected to continue until 2003 (see Table 5) (60). This study will search for biological prognostic factors and examine the rates of cancer and birth defects in children born to survivors of Wilms tumor. 

If the phase separation proceeds much faster than the cure rate, then the morphology is controlled by the phase separation rate rather than by the cure rate. The diffusivity of the thermoplastic in the thermoset becomes the most important factor. The increase of the diffusivity with increasing cine temperature causes the increase in the particle size. 

Even with all other factors accounted for, it remains very difficult to conclusively attribute lower-than-expected cure rates to the worms. The only sure way to do this is to collect eggs from patients not responding to therapy and use the resultant miracidia to infect snails. The cercariae emerging from those snails can then be used to generate murine infections, and if these murine infections are significantly more difficult than control infections to cure with praziquantel, there is some indication that the worms contributed to the lack of cure. But, this is a rather long and arduous process. 

Ongoing epidemiological and laboratory studies continue to elucidate a number of factors that can contribute to lower-than-expected cure rates for praziquantel. As these factors become more clearly and precisely understood, variability in the field results with the drug will be less ambiguous and significant drug failures may be identified more readily. 

The prepolymer as received from the manufacturer has a simple chain that has been terminated with an isocyanate. The isocyanate ends with this magical NCO group. The NCO is the reactive part of it. The higher the percentage of NCO in the prepolymer, the harder the material will be. An 80 Shore A will have an NCO of approximately 3.1 to 3.2%, whereas a 75 Shore D will have an NCO content of about 11.2%. To obtain the chain extension, one must add an appropriate amount of an amine or diol curative. For every curative, there is a different amount that must be added. The manufacturers of the prepolymers and curatives will give the appropriate factors for mixing the polyurethane. The prepolymer must be heated before use. This is to reduce the viscosity of the material as well as to obtain the correct cure rate and complete cure time. 

Since epoxy formulations are generally good thermal insulators, the exotherm will depend on the mass of the system. A high rate of exotherm is needed with some epoxy adhesive systems to achieve practical curing rates. However, excessively high exothermic temperatures can result in bubble formation, thermal degradation, and even a potentially hazardous situation. Control of the exotherm is, therefore, a very important factor in formulating epoxy adhesives. 

Cure Rate as Measured by Strength Development of Prototype Joints. Cure rate is an important factor when the expense of jigs and fixturing equipment is high or fast production rates are critical. It is also used as a quality control test to determine if the curing mechanism within the adhesive has changed from lot to lot or if it may have been spoiled by storage, moisture contamination, etc. 

The aim of any clinical trial is to have small Type 1 and n errors and consequently sufficient power to detect a difference between treatments, if it exists. Of the four factors that determine sample size, the power and significance level are chosen to suit the level of risk felt to be appropriate the magnitude of the effect can be estimated from previous experience with drugs of the same or similar action the variabiUty of the measurements is often known from published experiments on the primary endpoint, with or without drug. These data will, however, not be available for novel substances in a new class and frequently the sample size in the early phase of development is chosen on a more arbitrary basis. As an example, a trial that would detect, at the 5% level of statistical significance, a treatment that raised a cure rate from 75% to 85% would require 500 patients for 80% power. 

Supervised treatment of P. vivax malaria with chloroquine (600 mg on day 1, 450 mg on days 2 and 3) and primaquine (15 mg/day for 14 days) has been studied in 50 patients in a non-endemic area of Brazil in a prospective open trial (3). G6PD status was not checked. The relapse-free cure rate at 6 months was 86%. There were no important adverse events. Risk factors for relapse included lower doses of primaquine. In patients over 60 kg in weight, the dose of primaquine can fall short of recommendations (0.25-0.3 mg/kg/day), and this can contribute to the risk of relapse. 

Multigene studies have shown that interleukin (IL)-1 3 genetic polymorphism, although not an independent factor in treatment outcome, influences the impact of the CYP2C19 genotype on the cure rate of 1-week triple therapy for H. pylori infections. ... 

The approach to therapy is to remove or improve any predisposing factors if they can be identified. A pharmacologic agent should have limited local and systemic side effects, a high cure rate, and easy administration. Additionally, it would be advantageous to use a therapy that is able to resolve symptoms within 24 hours, that has broad antimycotic activity (to cover increasing rates on non-albicans Candida), that prevents recurrence, and that can be used over a shortened period of time such as 1 to 3 days. 

In summary, the results show that a small variation in the nature (i.e., polarity and functionality) of the diamine or the epoxidized triglyceride oil leads to a big difference in thermoset morphology in terms of particle-size distribution (Table V) and phase inversion (Table VI). In addition to the nature of the diamines and the oils, other factors, such as their reactivity, are expected to influence the phase-separation process. Although we do not have data, a small difference in the cure rates of the DDM formulations at 75 °C and the DDS formulations at 150 °C might affect both the particle-size distribution and phase inversion. 

An experiment was done keeping the ligand constant and varying the base metal. This was to evaluate whether the metal has an influencing factor on the overall cure rate. The catalysts used were cupric, manganic and ferric acetylacetonates. The concentration of catalyst varied from 1.50% to 8.00% by weight and were added alone and in combinations of two. The experiment consisted of viscosity measurements over time using a Brookfield Viscometer. 

Conversion from the [PS7+] to the [psi ] state is known as curing. While this phenomenon occurs spontaneously at a low frequency (Cox, 1965), both chemical and biological factors that increase curing rates have been identified. New information is emerging on the molecular mechanisms by which these treatments act, and these studies provide new insights into the prion replication process in vivo. 

The statements made above apply regardless of the crosslinking system used. When the crosslinker is changed, the skin formation time and the tack free time may change but the effect on the deep section cure rate is minimal, since the rate of water permeation through the cured skin is generally the rate-controlling factor in the cure of one-component RTV silicone sealants. 

Variation of the components of a coating formulation can produce improvements in the performance of the coating. Recent technology for the photoinitiator component has emerged which gives higher effective radical yields and faster rates of cure.( ) Many factors must be considered in the choice of reactive diluents used in a UV-curable coating formulation.(2-4) Each diluent has a... 

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