Evaluation of the effects of acetyl tributyl citrate as bio‐based plasticizer on the physical,thermal, and dynamical mechanical properties of poly(vinyl chloride)/polymethyl methacrylate blends

This article details our work in studying the plasticization of Poly(vinyl chloride) (PVC)/Polymethyl methacrylate (PMMA) blends with bio‐based acetyl tributyl citrate (ATBC) in place of conventional plasticizers such as di(2‐ethylhexyl) phthalate. PMMA was blended with PVC in various ratios from 0 to 100 wt% by melt compounding with or without the plasticizer ATBC. Both the glass transition temperatures of the blends (differential scanning calorimetry) and Tα (dynamic mechanical thermal analysis) are consistent with a miscibility of the components, and Fourier transforms infrared spectroscopy studies show that there are specific interactions in the PVC/PMMA blends favoring the miscibility. The thermal degradation of the blends was studied by thermogravimetric analysis that shows the thermal degradation of rigid and plasticized PVC/PMMA is a process composed of two‐steps and that PMMA exercises a stabilizing effect on the thermal degradation of PVC during the first step by decreasing the rate of dehydrochlorination. J. VINYL ADDIT. TECHNOL., 25:E73–E82, 2019. © 2018 Society of Plastics Engineers     

Effect of the addition of H2 and H2O on the polluting species in a counter-flow diffusion flame of biogas in flameless regime

Biogas is obtained by fermentation of biomass, it is a renewable fuel and practically CO₂ neutral, offers a significant advantage compared to other fuels for its low carbon/hydrogen ratio (1 atom of carbon and 4 hydrogen atoms). Thus, the level of CO₂ emissions from biogas is lower than that of the other fuels. Biogas is a biodegradable and renewable fuel; its benefits are conjugated especially in a flameless combustion process that significantly reduces fuel consumption and polluting emissions. In this paper, we study the effects of the dilution of a mixture of the biogas BG75 (75% CH₄ and 25% CO₂) – hydrogen by a volume of water vapor ranging from 10% to 50%. The configuration of an opposed jet flame is used with a constant strain rate of 120 s^?1. The chemical kinetics is described by the Gri3.0 mechanism. It has been found that the combustion structure is very sensitive to the various parameters.     

Thermal stability and Kinetic Study of rigid and plasticized Poly(vinyl chloride)/Poly(methylmethacrylate) blends

The thermal stability and kinetic parameters for degradation of rigid and plasticized poly(vinyl chloride)/poly (methylmethacrylate) blends have been investigated by using nonisothermal thermogravimetry in a flowing atmosphere of air. For that purpose, blends of variable composition from 0 to 100 wt% were prepared in the presence (15, 30, and 50 wt%) and in the absence of di‐(‐2‐ethyl hexyl) phthalate as plasticizer. Measurements were carried out in the temperature range of 30–550°C and at various heating rates (5, 10, 20, and 40°C/min). The kinetic parameters (E_a and A) were determined by applying the integral Kissinger method. Results indicate that these parameters and the thermal stability of the blends are dependent on the blend composition and the amount of plasticizer present. J. VINYL ADDIT. TECHNOL., 21:102–110, 2015. © 2014 Society of Plastics Engineers     

Transport phenomena effect on the performance of proton exchange membrane fuel cell (PEMFC)

The aim of this work is to present a two-dimensional transient model, of heat and mass transfer in a proton exchange membrane fuel cell (PEMFC). The model includes various conservation equations such as mass (hydrogen, oxygen, water concentration), Momentum and energy equations this model is combined with the electrochemical model.     

Development on the Natural Iteration Method in the Cluster Variation Method: Application in the First-Order Transition

We develop the natural iteration method (NIM) in the cluster variation method (CVM) using the congruence between input and output maximum cluster probabilities in the procedure of iteration. In this method, the effective chemical potential \upmu_i^* \upmu_{i}^{*} is not necessarily fixed, and one can calculate the equilibrium in a certain grand potential Ω. This property is absent in the cluster variation method using the natural iteration method or the Newton-Raphson (N-R) method. When the new method is used, the calculations of binary phase diagrams for first-order transitions are easy, and one can obtain high precision results for CVM calculations in a short period of time using ordinary micro-computers. We illustrate this development by its application in \textA1/L1 ₀ / \textL1 ₂ {\text{A1/L1}}_{ 0} / {\text{L1}}_{ 2} binary phase diagram.     

Viscoelastic properties,morphology, and thermal stability of rigid and plasticized poly(vinyl chloride)/poly(methyl methacrylate) blends

Viscoelastic properties, morphology, and thermal stability of rigid and plasticized poly(vinyl chloride)/poly (methyl methacrylate) (PVC/PMMA) blends were studied. For that purpose, blends of variable composition from 0 to 100 wt% were prepared in the presence (15, 30, and 50 wt%) and in the absence of di(2‐ethylhexyl) phthalate as plasticizer. Their miscibility was investigated by using dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). The DMTA and SEM results showed that the two polymers are miscible. Thermogravimetric studies on these blends were carried out in a flowing atmosphere of air from ambient temperature to 550°C. The results showed that the thermal degradation of rigid and plasticized PVC/PMMA in this broad range of temperature is a three‐step process and that PMMA exerted a stabilizing effect on the thermal degradation of PVC during the first step by reducing the rate of dehydrochlorination. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Controlling power output of solar chimney power plant according to demand

ABSTRACT

The solar chimney power plant (SCPP) is a simple solar thermal power plant that is capable of converting solar energy into thermal energy in the solar collector. In the second stage, the generated thermal energy is converted into kinetic energy in the chimney and ultimately into electric energy using a combination of a wind turbine and a generator. The numerical simulations were performed for the geometry of the prototype in Manzanares, Spain. Using computational ?uid dynamics (CFD) techniques; we have simulated a two-dimensional axisymmetric model of a SCPP with the RNG k-ε turbulence. In this model, the discrete ordinates (DO) radiation model was implemented to solve the radiative transfer equation, using a two-band radiation model. The main objective of this work is to explore dynamic control over plant power output. We have presented a technique to control the power output of the solar chimney power plant, in order to deliver power according to specified demand patterns. In order to present this, the reference plant model was modified to include a secondary and tertiary collector roof under the existing main collector. In terms of base load electricity generation, the inclusion of a secondary and tertiary collector roof produces good control over plant output.