A Simple Generic Model for Estimating Saturated Vapor Pressure

Arguably, the most important of the basic thermodynamic properties of fluids, vapor pressure has been the focus of investigation for over a century. The two main drawbacks of the models currently used for its correlation are that they either exhibit large deviations near critical temperature and triple point or that they have a large number of compound-specific adjusted parameters and hence the inconvenient necessity of having at hand large tabulations of hundreds of model parameters. In this study, by employing the up and coming procedure of genetic programming, a new model, which to a large extent remedies these shortcomings, is proposed. Essentially, having only two compound-specific adjusted parameters and also using two readily available substance parameters of molecular weight and normal boiling point ensure a high level of convenience, yet precision and applicability over a large portion of the vapor–liquid coexistence curve. Concisely, a sizable database comprised of 58,272 data points was gathered for 243 organic and inorganic compounds and elements belonging to a diverse set of chemical families; these were then used in both developing and validating the proposed model and reporting generic and compound/element-specific adjusted parameters. Average absolute relative deviations (AARDs) of 1.47% (for a subset of 40,852 data points) and 1.82% (for a subset of 17,420 data points) for the general model and a slightly modified model applicable to hydrogen-bonded alcohols and phenols, respectively, are a testament to the reliability of the new proposed model.     

Conventional vs. Temperature-Gradient Transient Liquid Phase Bonding of Stainless Steel 304 Using a Multi-component (Fe–Ni–Mo–B) Filler Metal

Metallurgical and Materials Transactions A - The application of the multi-component Fe-based filler metals (FMs) for transient liquid phase (TLP) bonding of AISI 304 austenitic stainless steel has...     

More comprehensive 3D modeling of clay‐like material drying

Drying process plays an important role in the manufacturing of many products such as ceramic, kitchenware and building materials, some of which have complex three‐dimensional (3D) geometry. To deal with many restrictions found in literatures, a 3D numerical approach was used to describe the drying process of a porous Clay‐like material. The problem investigated involves highly coupled equations considering heat, mass, and mechanical aspects. The model is validated through the comparison of experimental measurements with simulation result. Simulation results show that increasing the initial moisture content and reducing the initial temperature have the same privilege and without significant increase in drying time, it reduces slightly the amount of maximum stress but delays the occurrence time of maximum stress. The nonuniform heat expansion induced stresses are very small in comparison to nonuniform moisture shrinkage induced stresses and can be neglected in drying simulation. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1469–1478, 2018     

A revised sales rebate contract with effort‐dependent demand: a channel coordination approach

In this paper, simultaneous coordination of order quantity and sales effort (SE) decisions in a supplier/retailer system with stochastic effort‐dependent demand is investigated. The main aim of the proposed model is to attain an optimal balance that results in a Pareto‐efficient solution for both channel members. A revised sales rebate (RSR) contract is developed to achieve channel coordination. In addition to the usual incentive approach of sales rebate schemes, a punitive approach is designed for the new proposed contract as a stockout penalty. Furthermore, some numerical experiments are examined to analyze the performance of the presented model under three decision‐making scenarios (i.e., decentralized, centralized, and RSR). Additionally, some in‐depth sensitivity analyses are conducted to examine the behavior of the supply chain performance under alteration of different parameters. The results show that the proposed RSR contract leads to channel coordination, while both channel members experience a Pareto improving situation. Moreover, it is proved that the RSR contract has significant potential on neutralizing adverse impacts of demand fluctuations on channel performance indicators.     

A representation of extra-special 2-group, entanglement, and Berry phase of two qubits in Yang-Baxter system

In this paper we show another representations of extra-special 2-groups. Based on this new representation, we infer a ${\mathbb{M}}$ matrix which obeys the extra-special 2-groups algebra relations. We also derive a unitary ${\breve{R}(\theta,\varphi)}$ matrix from the ${\mathbb{M}}$ using the Yang-Baxterization process. A Hamiltonian for the two qubits is constructed from the unitary ${\breve{R}(\theta,\varphi)}$ matrix. In this way, we study the Berry phase and entanglement of the two-qubit system. The results also establish relations between topological and holonomic quantum computation.     

E2EACK: an end-to-end acknowledgment-based scheme against collusion black hole and slander attacks in MANETs

Mobile ad hoc networks (MANETs) rely on the benevolence of nodes within the network to forward packets from a source node to a destination node. This network construction allows for the forwarding nodes, whether they are selfish or malicious, to drop packets hindering end-to-end communication. In this paper, a new scheme is proposed against collusion black hole and slander attacks in MANETs, named E2EACK. A novel method is used to detect collusion attacks due to collusive malicious nodes which cooperate in the route discovery, but refuse to forward data packets and do not disclose the misbehavior of each other. Contrary to existing methods that detect only collusion black hole attacks, the E2EACK also detects slander attacks and framing attacks. Moreover, the E2EACK uses ACKnowledgment packet to detect malicious nodes on the path and Message Authentication Code (MAC) to authenticate the sender of each data packet. Analytical and simulation results show that the proposed scheme considerably decreases the routing overhead and increases the packet delivery ratio compared to the existing methods.     

Study of the corrosion behavior of zinc and Zn–Co alloy electrodeposits obtained from alkaline bath using direct current

The corrosion behavior of Zn and Zn–Co alloy electrodeposits that were obtained from weakly alkaline glycine solutions has been studied. SEM, EDS and XRD were used to study surface morphology, chemical composition and phase structure of the coatings. Corrosion behavior of Zn and Zn–Co alloy coatings was studied by using potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. The results showed that increasing current density during deposition, increases cobalt content of the coating. It was also shown that increasing current density, up to 15 mA cm⁻², decreases the grain size and further increase in current density increases the grain size of the deposit. It was also noticed that corrosion resistance of deposits was highly influenced by the composition and morphology of the coatings. Zn–Co deposit containing 0.89 wt.% Co showed the highest corrosion resistance due to its single phase structure and its finer morphology.     

Evaluation on Properties of CaO-BaO-B2O3-Al2O3-SiO2 Glass-Ceramic Sealants for Intermediate Temperature Solid Oxide Fuel Cells

To develop suitable sealants for intermediate temperature solid oxide fuel cells (IT-SOFC), glasseceramics based on the CaO-BaO-B2O3-Al2O3-SiO2 system were studied. Coefficient of thermal expansion (CTE), glass transition temperature (Tg) and dilatometric softening point temperature (Td) of specimens were determined by means of dilatometer analysis and crystallization temperature was measured by differential thermal analysis (DTA). Also, crystallization behavior during prolonged heat-treatment and microstructure properties were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Electrical properties were measured at different temperatures, and the results showed a high resistance (>10 4Ω) at the SOFC operation temperature (600-800℃). Moreover, mechanical properties of heat-treated specimens (1, 10, 30, 50 h) were measured. Microstructure investigation revealed a well-adhered bonding between the sealant glasseceramic electrolyte and glass.     

Brine clarity maintenance in salinity-gradient solar ponds

Brine transparency is an important part of the maintenance of a salinity-gradient solar pond as it affects the amount of solar radiation reaching the storage zone and hence has an influence on the thermal performance. There is a wide range of factors that can hinder the transmission of light in a solar pond. Algal and microbial growths are the most common problems encountered in working solar ponds and control of their densities is essential to maintain transparency. Two different chemical treatment methods for algae growth prevention are described in this paper: chlorine and a novel chemical product – copper ethylamine complex. The latter method has never been implemented previously in a working pond. This paper discusses the theory of the algae control methods used and presents the experimental results of the chemical treatments. The results showed that Cupricide is more effective than chlorine and is therefore the recommended chemical for algae control in solar ponds; it improves the water transparency especially in the upper convective zone and lower convective zone with all measurement values less than 1 NTU. Chlorine was found to be more corrosive than Cupricide due to the acidic effect it has on the pH. The preliminary cost analysis showed that granular chlorine is the cheapest chemical. A more detailed financial analysis is nevertheless required to refine these costs.