Study of the solvent effect on miscibility between poly(vinyl chloride) and poly(methyl methacrylate) in the solution state – viscometric measurements

In this work, the solvent effect on the miscibility between poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) in ternary polymer solutions was examined by the viscometric method. In these systems, we could understand that the used solvents, tetrahydrofuran (THF) or N,N‐dimethylformamide (DMF), mainly affect the interaction between PVC and PMMA, while prompting various miscible properties. In PVC/PMMA/THF solution, THF is a near θ‐solvent and a poor solvent for PVC and PMMA, respectively. The mixing of the tighter PMMA coils and more extended PVC coils in THF may cause the sea–island heterogeneous structure below the weight fraction of PMMA in the polymer mixture w_PMMA = 0.7, resulting in immiscible PVC/PMMA mixtures. At w_PMMA ≥ 0.7, the PVC/PMMA mixtures are relatively miscible, giving homogeneous polymer solutions. It means that the miscibility between PVC and PMMA depends on the composition of polymer mixture. However, due to the similar affinity of DMF to PVC and PMMA, PVC/PMMA/DMF solutions exhibit high miscibility between PVC and PMMA at about w_PMMA = 0.5. © 2000 Society of Chemical Industry     

Bivariate tolerance design for lock wheels by considering quality loss

In the design of tolerance allocation the cost–tolerance function is usually employed to represent the objective function which is to be minimized. The traditional cost–tolerance functions in the literature are concerned with only one characteristic. In this paper we obtain a bivariate cost–tolerance function to describe the relationship between the cost and tolerances of two characteristics (i.e. the thickness and inner diameter) of a lock wheel. Then the bivariate loss function is combined with the bivariate cost–tolerance function to determine the optimal tolerances for the thickness and inner diameter of a lock wheel such that the user's potential loss/cost may be evaluated. When the quality loss is considered, the tolerances of both characteristics become tighter. By including the effect of product degradation, the present work of expected bivariate quality loss is then introduced as a quality performance measure. By assuming linear drifts on both the thickness and inner diameter of the lock wheels, the model with the present worth of quality loss leads to tighter tolerances of both characteristics. In addition, a longer planning horizon (or a longer useful life of the product) leads to tighter tolerances and a larger user's discount rate results in looser tolerances for both characteristics. Copyright © 2000 John Wiley & Sons, Ltd.     

Empagliflozin Ameliorates Free Fatty Acid Induced-Lipotoxicity in Renal Proximal Tubular Cells via the PPARγ/CD36 Pathway in Obese Mice

High serum levels of free fatty acids (FFAs) could contribute to obesity-induced nephropathy. CD36, a class B scavenger receptor, is a major receptor mediating FFA uptake in renal proximal tubular cells. Empagliflozin, a new anti-diabetic agent, is a specific inhibitor of sodium-glucose co-transporter 2 channels presented on renal proximal tubular cells and inhibits glucose reabsorption. In addition, empagliflozin has shown renoprotective effects. However, the mechanism through which empagliflozin regulates CD36 expression and attenuates FFA-induced lipotoxicity remains unclear. Herein, we aimed to elucidate the crosstalk between empagliflozin and CD36 in FFA-induced renal injury. C57BL/6 mice fed a high-fat diet (HFD) and palmitic acid-treated HK-2 renal tubular cells were used for in vivo and in vitro assessments. Empagliflozin attenuated HFD-induced body weight gain, insulin resistance, and inflammation in mice. In HFD-fed mice, CD36 was upregulated in the tubular area of the kidney, whereas empagliflozin attenuated CD36 expression. Furthermore, empagliflozin downregulated the expression of peroxisome proliferator-activated receptor (PPAR)-γ. Treatment with a PPARγ inhibitor (GW9662) did not further decrease PPARγ expression, whereas a PPARγ antagonist reversed this effect; this suggested that empagliflozin may, at least partly, decrease CD36 by modulating PPARγ. In conclusion, empagliflozin can ameliorate FFA-induced renal tubular injury via the PPARγ/CD36 pathway.     

Accounting for rain effects in building energy estimation

We demonstrate a methodology to account for rain effects on wall heat gain using the DOE-2 building energy estimation software as a reference. The methodology involves modifying the boundary conditions used for estimating heat flow through exterior wall components. Information on boundary conditions during rain is obtained from a classification of rain patterns from local weather data. The DOE-2 computer code, with the appropriate modifications, is calibrated with experimental results obtained for both dry and wet outdoor conditions. Finally, the calibrated code is used to estimate the reduction in heat gain due to rain by a porous building wall for different rain patterns. The annual heat gain reduction is also estimated for a typical tropical climate. © 1998 John Wiley & Sons, Ltd.     

Mechanical characterization of triaxially braided hybrid composites

The use of advanced composites has been expanded to the oil and gas industry. One of the newly developed technologies is in composite coiled tubing that offers the potential of exceeding the performance of metallic tubings. The high strains due to bending and the complex state of stress in these tubes necessitate the better understanding of the correlation between fiber architecture and tube performance. Braided composites can withstand high bending deformation without severe degradation of properties. In this study, braided hybrid composites are presented as an option for achieving high performance coiled tubing under tensile and flexural loads. The effects of material and fabric microstructural parameters on the mechanical behavior of braided hybrid composites are studied. The mechanical characterization of triaxially braided composites has identified the influence of the mechanical properties of the axial yarn, the axial yarn volume fraction, and the braid angle. Overall, this study provides a sound knowledge base for the design, fabrication, and characterization of triaxially braided composites for coiled tubing applications in the petroleum industry.     

On the eigenvalues of a uniform cantilever beam carrying any number of spring–damper–mass systems

The eigenvalues of a uniform cantilever beam carrying any number of spring–damper–mass systems with arbitrary magnitudes and locations were determined by means of the analytical‐and‐numerical‐combined method (ANCM). First of all, each spring–damper–mass system was replaced by a massless effective spring with spring constant k_eff, which is the main point that the ANCM is available for the present problem. Next, the equation of motion for the ‘constrained’ beam (with spring–damper–mass systems attached) was derived by using the natural frequencies and normal mode shapes of the ‘unconstrained’ beam (without carrying any attachments) incorporated with the expansion theorem. Finally, the equation of motion for the ‘constrained’ beam in ‘complex form’ is separated into the real and the imaginary parts. From either part, a set of simultaneous equations were obtained. Since the simultaneous equations are in ‘real form’, the eigenvalues of the ‘constrained’ beam were determined with the conventional numerical methods. To confirm the reliability of the presented theory, all the numerical results obtained from the ANCM were compared with the corresponding ones obtained from the conventional finite element method (FEM) and good agreement was achieved. Because the order of the property matrices for the equation of motion derived by using the ANCM is much lower than that by using the conventional FEM, the storing memory and the CPU time required by the ANCM are much less than those required by the FEM. Besides, the solution of the equation of motion derived from the ANCM can always be obtained with the general personal computers, but that from the FEM can sometimes be obtained only with the computers of workstations or main frames when the total degrees of freedom exceeding a certain limit. Copyright © 1999 John Wiley & Sons, Ltd.     

GRPEL2 Knockdown Exerts Redox Regulation in Glioblastoma

Malignant brain tumors are responsible for catastrophic morbidity and mortality globally. Among them, glioblastoma multiforme (GBM) bears the worst prognosis. The GrpE-like 2 homolog (GRPEL2) plays a crucial role in regulating mitochondrial protein import and redox homeostasis. However, the role of GRPEL2 in human glioblastoma has yet to be clarified. In this study, we investigated the function of GRPEL2 in glioma. Based on bioinformatics analyses from the Cancer Gene Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA), we inferred that GRPEL2 expression positively correlates with WHO tumor grade (p < 0.001), IDH mutation status (p < 0.001), oligodendroglial differentiation (p < 0.001), and overall survival (p < 0.001) in glioma datasets. Functional validation in LN229 and GBM8401 GBM cells showed that GRPEL2 knockdown efficiently inhibited cellular proliferation. Moreover, GRPEL2 suppression induced cell cycle arrest at the sub-G1 phase. Furthermore, GRPEL2 silencing decreased intracellular reactive oxygen species (ROS) without impending mitochondria membrane potential. The cellular oxidative respiration measured with a Seahorse XFp analyzer exhibited a reduction of the oxygen consumption rate (OCR) in GBM cells by siGRPEL2, which subsequently enhanced autophagy and senescence in glioblastoma cells. Taken together, GRPEL2 is a novel redox regulator of mitochondria bioenergetics and a potential target for treating GBM in the future.     

Online gasoline blending with EPA Complex Model for predicting emissions

The empirical Complex Model developed by the US Environmental Protection Agency (EPA) is used by refiners to predict the toxic emissions of reformulated gasoline with respect to gasoline properties. The difficulty in implementing this model in the blending process stems from the implicit definition of Complex Model through a series of disjunctions assembled by the EPA in the form of spreadsheets. A major breakthrough in the refinery-based Complex Model implementation occurred in 2008 and 2010 through the use of generalized disjunctive and mixed-integer nonlinear programming (MINLP). Nevertheless, the execution time of these MINLP models remains prohibitively long to control emissions with our online gasoline blender. The first objective of this study is to present a new model that decreases the execution time of our online controller. The second objective is to consider toxic thresholds as hard constraints to be verified and search for blends that verify them. Our approach introduces a new way to write the Complex Model without any binary or integer variables. Sigmoid functions are used herein to approximate step functions until the measurement precision for each blend property is reached. By knowing this level of precision, we are able to propose an extremely good and differentiable approximation of the Complex Model. Next, a differentiable objective function is introduced to penalize emission values higher than the threshold emissions. Our optimization module has been implemented and tested with real data. The execution time never exceeded 1 s, which allows the online regulation of emissions the same way as other traditional properties of blended gasoline.     

Synthesis of Titanium Oxycarbide from Titanium Slag by Methane-Containing Gas

In this study, reaction steps of a process for synthesis of titanium oxycarbide from titanium slag were demonstrated. This process involves the reduction of titanium slag by a methane-hydrogen-argon mixture at 1473 K (1200 °C) and the leaching of the reduced products by hydrofluoric acid near room temperature to remove the main impurity (Fe₃Si). Some iron was formed by disproportionation of the main M₃O₅ phase before gaseous reduction started. Upon reduction, more iron formed first, followed by reduction of titanium dioxide to suboxides and eventually oxycarbide.     

Algorithms for the single machine total weighted completion time scheduling problem with release times and sequence-dependent setups

This paper considers the problem of scheduling n jobs on a single machine to minimize the total weighted completion time in the presence of sequence-dependent setup times and release times. To the best of our knowledge, little research has been devoted to this scheduling problem. Therefore, we developed two exact algorithms, including a constraint programming model and a branch-and-bound method for small problems. The obtained optimal solutions can be used as a benchmark for evaluating the performance of heuristics. With the complexity in mind, two heuristics, including a best index dispatch (BID) and a modified weighted shortest processing time (MWSPT) based on non-delay concepts are also proposed for large problems. The time complexities of the two proposed heuristics are O(n ⁴) and O(n ³), respectively. The computational results showed that the branch-and-bound method could solve most instances with 40 jobs under the time limit of 7,200 s. The BID heuristic is superior to the MWSPT in solution quality, although both can efficiently and effectively obtain near-optimal solutions for large instances.