Predicting the lifetime of CPVC under increasing temperature and crosshead speed

CPVC is an increasingly popular material for plumbing pipes and other applications that require strong and temperature-resistant material. This resin is created using a chlorination process, giving it Chlorine levels that range from 63 to 69% and thus a unique set of characteristics that make it ideal for certain applications. CPVC's combination of corrosion-resistance and low installation costs make it a great substitute for copper in environments with non-ambient conditions such as higher temperatures. This makes it an economic choice for many projects that require smaller budgets. With a variety of applications, CPVC provides a great alternative requiring strong and durable material. The aim of this paper is to characterize the mechanical characteristics of chlorinated PVC (CPVC). Tensile tests were carried on the compounds at different temperatures ranging from -20 to 90°C and crosshead speeds from 5 to 500 mm/min. The results were analyzed to determine how crosshead speed and temperature affected on the mechanical characteristics of CPVC specimens. Two damage models are then developed, one model obtained through by adapting the unified theory version and the other quasi-experimental static model based on ultimate stress. These models allow us to evaluate the damage evolution of CPVC samples and to determine the safety and maintenance intervals of this material

A Numerical Study of the Damage Mechanisms for CT Tensile Specimens of P265GH Steel Material

The aim of this paper is to determine the damage mechanisms of P265GH steel, commonly used for pressure equipment. First, an experimental study using tensile and Charpy tests allowed us to determine the mechanical properties (Young modulus E = 200 GPa, elongation ε = 35%, yield se = 320 MPa, ultimate stress su = 470 MPa, and KIC = 96 MP√m). Then, numerical finite element modeling on a CT specimen using the CASTEM calculation code allowed us to determine the damage of the material when the notch depth varies. The analysis of the results shows that the numerical values of the stress concentration coefficient Kt and the stress intensity factor KI are comparable with the analytically calculated values, thus validating our numerical study. The numerical results obtained revealed that the maximum stress σmax is located in the vicinity of the notch bottom and the high probability density corresponds to a high loading level

Prediction of thermomechanical behavior of acrylonitrile butadiene styrene using a newly developed nonlinear damage-reliability model

The aim of this work was to evaluate the influence of temperature on the mechanical behavior of an amorphous polymer, namely acrylonitrile butadiene styrene (ABS), based on a series of uniaxial tensile tests on smooth specimens at different temperatures. The results demonstrate that the behavior of the polymers is strongly dependent on the temperature. Its influence on the physical characteristics during the study of polymer behaviors cannot be denied, particularly when the processes of shaping are investigated, which require significant contributions of heat and mechanical effort. For this reason, this study consists of predicting the evolution of ABS damage in two main zones. The first is the industrial zone, in which the configuration of macromolecular chains is largely immobile, and the temperature is below the glass temperature (Tg = 110°C). In this zone, a damage model based on the obtained experimental results allowed us to determine three stages of damage evolution, and then to specify the critical fraction of life, at which the material becomes unstable and defective, for the purpose of predictive maintenance. The second zone is that of thermoforming, in which the temperature is above the glass temperature, Tg. In this zone, the macromolecular chains tend to move more freely as the temperature increases. The same damage model was adopted to follow the flow process according to the fraction of life that represents the critical material parameter. This study also includes a comparison between the static (experimental) damage models and unified theory (theoretical) damage models

Predicting the lifetime of CPVC under increasing temperature and crosshead speed

CPVC is an increasingly popular material for plumbing pipes and other applications that require strong and temperature-resistant material. This resin is created using a chlorination process, giving it Chlorine levels that range from 63 to 69% and thus a unique set of characteristics that make it ideal for certain applications. CPVC's combination of corrosion-resistance and low installation costs make it a great substitute for copper in environments with non-ambient conditions such as higher temperatures. This makes it an economic choice for many projects that require smaller budgets. With a variety of applications, CPVC provides a great alternative requiring strong and durable material. The aim of this paper is to characterize the mechanical characteristics of chlorinated PVC (CPVC). Tensile tests were carried on the compounds at different temperatures ranging from -20 to 90°C and crosshead speeds from 5 to 500 mm/min. The results were analyzed to determine how crosshead speed and temperature affected on the mechanical characteristics of CPVC specimens. Two damage models are then developed, one model obtained through by adapting the unified theory version and the other quasi-experimental static model based on ultimate stress. These models allow us to evaluate the damage evolution of CPVC samples and to determine the safety and maintenance intervals of this material

Towards the clinical implementation of pharmacogenetics in bipolar disorder.

BackgroundBipolar disorder (BD) is a psychiatric illness defined by pathological alterations between the mood states of mania and depression, causing disability, imposing healthcare costs and elevating the risk of suicide. Although effective treatments for BD exist, variability in outcomes leads to a large number of treatment failures, typically followed by a trial and error process of medication switches that can take years. Pharmacogenetic testing (PGT), by tailoring drug choice to an individual, may personalize and expedite treatment so as to identify more rapidly medications well suited to individual BD patients.DiscussionA number of associations have been made in BD between medication response phenotypes and specific genetic markers. However, to date clinical adoption of PGT has been limited, often citing questions that must be answered before it can be widely utilized. These include: What are the requirements of supporting evidence? How large is a clinically relevant effect? What degree of specificity and sensitivity are required? Does a given marker influence decision making and have clinical utility? In many cases, the answers to these questions remain unknown, and ultimately, the question of whether PGT is valid and useful must be determined empirically. Towards this aim, we have reviewed the literature and selected drug-genotype associations with the strongest evidence for utility in BD.SummaryBased upon these findings, we propose a preliminary panel for use in PGT, and a method by which the results of a PGT panel can be integrated for clinical interpretation. Finally, we argue that based on the sufficiency of accumulated evidence, PGT implementation studies are now warranted. We propose and discuss the design for a randomized clinical trial to test the use of PGT in the treatment of BD