Design of Recycle/Reuse Networks with Thermal Effects and Variable Sources

Recycle/reuse networks are commonly used in industrial facilities to conserve natural resources, reduce environmental impact, and improve process economics. The design of these networks is a challenging task because of the numerous possibilities of assigning stream (process sources) to units that may potentially employ them (process sinks). Additionally, several fresh streams with different qualities and costs may be used to supplement the recycle of process streams. The selection of the type and flow of these fresh resources is an important step in the design of the recycle/reuse networks. This work introduces systematic approaches to address two new categories in the design of recycle/reuse networks: (a) The incorporation of thermal effects in the network. Two new aspects are introduced: heat of mixing of process sources and temperature constraints imposed on the feed to the process sinks iv (b) Dealing with variation in process sources. Two types of source variability are addressed: flowrate and composition For networks with thermal effects, an assignment optimization formulation is developed. Depending on the functional form of the heat of mixing, the formulation may be a linear or a nonlinear program. The solution of this program provides optimum flowrates of the fresh streams as well as the segregation, mixing, and allocation of the process sources to sinks. For networks with variable sources, a computer code is developed to solve the problem. It is based on discretizing the search space and using the concept of "floating pinch" to insure solution feasibility and optimal targets. Case studies are solved to illustrate the applicability of the new approaches

Posttraumatic growth (PTG) and posttraumatic depreciation (PTD) across ten countries: Global validation of the PTG-PTD theoretical model

info:eu-repo/semantics/publishedVersio

Computational Study on the Kinetics and Mechanism of the Carbaryl + OH Reaction

Carbaryl is released into the atmosphere as a spray drift immediately following the application. In order to evaluate its fate in the atmosphere, a computational study on the kinetics of the OH radical reaction with carbaryl is presented. Different reaction paths are studied at the M05-2<i>X</i>/6-311++G­(d,p) level. A complex mechanism involving the formation of a stable reactant complex is proposed and the temperature dependence of the rate coefficients is studied in the 280–650 K temperature range. The principal degradation path is the hydroxyl radical addition to naphthalene, but hydrogen abstractions from the methyl group are identified as a secondary significant path. The rate coefficients, computed using the conventional transition state theory, reproduce quite well the scarce experimental data available

Radon Hydrides: Structure and Bonding

Quantum chemical calculations, using gradient-correct density functional at the BP86 level in conjunction with TZ2P basis sets, have been carried out for the radon hydrides HRnY (with Y = F, Cl, Br, I, CCH, CN, and NC). The bonding in HRnY is studied using different bond ruptures, establishing the role of those stabilizing (and destabilizing) factors that prevent these species to be dissociated. Although all HRnY systems studied here are bound equilibrium structures, they are metastable species with respect to the HRnY → Rn + HY decomposition channel. However, the HRnY → H + Rn + Y reaction is endothermic. So, these results indicate the possibility to identify the radon hydrides in noble-gas matrices. © the Owner Societies

The Biological Role of the ζ Subunit as Unidirectional Inhibitor of the F1FO-ATPase of Paracoccus denitrificans

The biological roles of the three natural F1FO-ATPase inhibitors, ε, ζ, and IF1, on cell physiology remain controversial. The ζ subunit is a useful model for deletion studies since it mimics mitochondrial IF1, but in the F1FO-ATPase of Paracoccus denitrificans (PdF1FO), it is a monogenic and supernumerary subunit. Here, we constructed a P. denitrificans 1222 derivative (PdΔζ) with a deleted ζ gene to determine its role in cell growth and bioenergetics. The results show that the lack of ζ in vivo strongly restricts respiratory P. denitrificans growth, and this is restored by complementation in trans with an exogenous ζ gene. Removal of ζ increased the coupled PdF1FO-ATPase activity without affecting the PdF1FO-ATP synthase turnover, and the latter was not affected at all by ζ reconstitution in vitro. Therefore, ζ works as a unidirectional pawl-ratchet inhibitor of the PdF1FO-ATPase nanomotor favoring the ATP synthase turnover to improve respiratory cell growth and bioenergetics

Comparison of the use of blood pressure telemonitoring versus standard medical care in the achievement of short-term therapeutic goals in blood pressure in patients with uncontrolled hypertension: An open-label clinical trial

Background In Mexico less than half of the treated hypertensive patients reach blood pressure (BP) targets. Most hypertensive individuals rely on the standard medical care (SMC) to achieve the BP control goals; however, the efficacy of BP telemonitoring (BPT) to achieve BP targets has been poorly studied. Aim To compare the efficacy of BPT versus SMC to achieve BP goals in patients with uncontrolled hypertension. Methods A two-arm, open-label clinical trial was conducted in patients ≥18 years with uncontrolled hypertension. The participants were randomized to 2 arms (BPT vs SMC) and followed for 12 weeks. For the statistical analysis, the chi-squared test and covariance were used. Results One hundred and seventy-eight participants were included, BPT (n = 94) and SMC (n = 84), after 12 weeks of follow up, we observed a baseline-adjusted reduction in systolic BP with both BPT (−13.5 [1.3] mmHg) and the SMC (−5.9 [1.4] mmHg; p < 0.001) but a greater decrease with BPT (p < 0.001). Likewise, we found a baseline-adjusted reduction of diastolic BP with BPT (−6.9 [0.9] mmHg) and SMC (−2.7 [0.9] mmHg) (p = 0.007) with a more significant percentage change from baseline with BPT (−6.8% [1.0] vs 2.5% [1.1]; p = 0.007). In the BPT arm, a larger proportion of patients achieved the BP target versus SMC (30.5% vs 12.8%; p = 0.005). Conclusion BPT showed a greater proportion of patients achieving office BP control goals (<140/90 mmHg), compared to standard medical care