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Purpose This paper considers an option contract in a two-stage supplier-retailer supply chain (SC) when market demand is stochastic. The problem is a Stackelberg game with the supplier as a leader. This research assumes demand information sharing. The purpose of this study is to determine the optimal pricing strategy of the supplier along with the optimal order strategy of the retailer in three option contract cases. Design/methodology/approach The paper model the option contract pricing problem as a bilevel problem. The problem is then solved using bilevel programing methods. After computing, the generated outcomes are compared to a benchmark (wholesale price contract) to evaluate the contract. Findings The results reveal that only one of the contract cases can arbitrarily allocate the SC profit. In both other cases, the Stackelberg supplier manages to earn the total SC profit. Further analysis of the first contract, show that from the supplier’s perspective, the first stage forecast inaccuracy is beneficial, whereas the demand uncertainty in the second stage is detrimental. This contracting strategy guarantees both players better outcomes compared to the wholesale price contract. Originality/value To the best of the authors’ knowledge, this research is the first that links the option contract literature to the bilevel programing literature. It also the first to solve the pricing problem of the commitment option contract with demand update where the retailer exercises the option before knowing the exact demand.

The pressure–volume–temperature (PVT) relationships for trimethoxymethylsilane (MTMS, CH3(CH3O)3Si) and tetramethyl orthosilicate (TMOS, (CH3O)4Si) were measured at temperatures ranging from 303.2 to 363.2 K and pressures up to 160 MPa. Density measurements were carried out with an experimental apparatus based on the variable volume method. The standard uncertainties u(T) = 0.17 K and u(P) = 0.14 MPa, and the relative combined expanded uncertainty Ur (0.95 level of confidence) were Ur(ρ) = (0.0016 and 0.0022) for MTMS and TMOS, respectively. The obtained PVT relationships were correlated using the Tait equation and the Sanchez–Lacombe equation of state to determine the characteristic parameters.

Equations of state (EoS) can be used to estimate a wide variety of physical properties. However, there has been limited verification of the applicability of parameter sets derived from specific physical properties to correlate and estimate various other physical properties. The densities of homogeneous phase fluid mixtures of the carbon dioxide (CO2)/toluene (Tol) binary system were measured and correlated to three equations of state. The density measurements were performed using a high-pressure vibration-type density meter equipped with a circulation pump and variable-volume viewing cell, which guaranteed the homogeneity of the mixtures. The densities were measured at temperatures ranging from 313 to 353 K, pressures up to 20 MPa, and CO2 concentrations from 0 to 80 mol%. The experimental data obtained were correlated to the Tait density equation and three EoS, namely Peng–Robinson (PR), Sanchez–Lacombe (SL), and Perturbed Chain statistical associating fluid theory (PC-SAFT) EoS. Among them, SL and PC-SAFT EoS agree better with the experimental data compared to the PR EoS, presumably due to differences in the pure component parameters used in each EoS. Using parameter sets determined from the density measurements, the vapor liquid equilibrium (VLE) of the CO2/Tol mixtures was estimated. While we were unsuccessful in estimating VLE using the PR EoS, SL and PC-SAFT EoS were successfully used for the estimations. We also attempted to determine the densities from VLE correlations. It was found that SL and PC-SAFT EoS could be used to estimate the density well, whereas the PR was not predictive. From the results of the study, it is clear that for estimating density using EoS, the basic data used for determining the pure component parameters are important.

The phase behaviors of carbon dioxide (CO2)/tetramethyl orthosilicate (TMOS)/poly(methyl methacrylate) (PMMA) and CO2/TMOS/poly(styrene) (PS) ternary systems were measured. The measurements were performed using a synthetic method involving observations of the bubble point and cloud point. The phase boundaries were measured at temperatures ranging from 313.2 K to 393.2 K and CO2 weight fractions ranging from 0.01 to 0.40. At a constant TMOS:polymer weight ratio of 9:1, both systems showed similar CO2 mass fraction dependence of their phase behaviors. When the vapor-liquid (VL) and vapor-liquid-liquid (VLL) phase boundaries of the ternary systems were compared with those of the binary CO2/TMOS system using polymer-free bases, they were found to be nearly identical. On the other hand, the two systems showed completely opposite polymer mass fraction dependence of their phase behaviors at a constant CO2 ratio.

The phase behaviors of carbon dioxide (CO2)/trimethoxy(methyl)silane (MTMS) and CO2/Methylsilicate 51 (MS-51: methylsilicate tetramer) binary systems were determined. The experiments were performed using a synthetic method by observing the bubble point. The phase boundaries were determined at temperatures of 313.2 K–393.2 K and CO2 molar fractions of 0.2–0.9. The experimentally obtained bubble points of the CO2/MTMS binary system were correlated using the Peng-Robinson equation of state (PR EoS), and the molecular interaction parameters kij and lij were determined. The results of the CO2/MS-51 binary system were correlated using the PR EoS and the Sanchez-Lacombe equation of state (SL EoS). In the SL EoS, two types of mixing rules, originally proposed by Sanchez et al. which uses kij as a fitting parameter and modified by McHugh et al. which uses two fitting parameters kij and lij, were used. For this system, the experimental results were correlated better using the SL EoS than using the PR EoS, and the latter mixing rule was more suitable than the former.

The pressure-volume-temperature (PVT) relationships of pure diisononyl phthalate (DINP) were measured at temperatures of 303.15–363.15 K and pressures up to 160 MPa by a variable-volume method. Using a synthetic method that involved observing the bubble point, the phase behavior of the CO2/DINP binary system was also measured. The phase boundaries were determined at temperatures of 313.15–393.15 K and CO2 molar fractions of 0.3–0.9. The characteristic parameters of DINP were obtained by correlating the measured PVT data using the Sanchez-Lacombe equation of state (SL EoS), and the bubble points of the system were correlated using the SL EoS with the determined characteristic parameters. The interaction parameter exhibited temperature dependence, and the introduction of the temperature dependence improved the correlation.

In this study, we introduced an artificial neural network (ANN), which can represent objects that are difficult to formulate, rather than the integrated model of the group contribution method (GCM), because the integrated model in the existing GCM is no longer able to manage enormous diversification of substances. Hence, a model to estimate the pure component parameters m, σ, and e of the perturbed chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) was developed. We optimized the structure of the ANN by changing the number of neurons and layers in the hidden layer. In this study, the optimized ANN structure was two hidden layers and 40 neurons. The results confirm that the model can determine the pure component parameters of PC-SAFT EoS, which can estimate the liquid density, saturated vapor pressure, and critical properties. In terms of the critical properties, the estimated results were almost as good or better than those obtained using the GCMs, which are specified for the critical properties. We were able to calculate properties for substances whose parameters were not reported in the literature by using this ANN. The results would be useful for chemical process design, for example, to be incorporated into process simulators.

Alkyl groups of tetraalkoxysilane have different chain lengths, which results in different reactivity of the sol–gel reaction. Hence, it is essential to understand the phase behavior for designing chemical processes using the sol–gel reaction. The phase behavior of CO2/tetrapropyl orthosilicate (TPOS) and CO2/tetrabutyl orthosilicate (TBOS) binary systems was measured. The experiments were performed using a synthetic method combined with a laser displacement measurement wherein the movement of the piston inside the high-pressure vessel was measured. The phase boundaries were determined at 313–373 K and CO2 molar fractions of 0.1–0.9. No significant difference was observed in the phase behavior of tetraalkoxysilanes, which have alkyl groups of different chain lengths. The experimentally obtained vapor–liquid equilibria of the two binary systems were correlated by the Sanchez–Lacombe equation of state using the original mixing rule reported by Sanchez et al. The results showed that molecular interaction parameter kij exhibits a clear temperature dependence.

The phase behavior of a carbon dioxide (CO2)/toluene (Tol)/polystyrene (PS) ternary system was measured. The measurements were performed using a synthetic method combined with a reflected light intensity measurement. The bubble points were determined by visual observation, and the cloud points were determined from the change in the reflected light intensity. The phase boundaries were measured at temperatures ranging from 313.2 K to 373.2 K and CO2 weight fractions ranging from 0.10 to 0.41. The homogeneous phase area decreased when the molecular weight of PS and/or the ratio of PS to Tol increased. It was found that the phase behavior of ternary systems, especially the liquid-liquid phase separation behavior, was altered by a change in the mutual solubility between the three components.

This Special Issue includes a selection of papers originally presented and discussed at the Twentieth International Working Seminar on Pro- duction and Operations Management, Innsbruck, February 19–23, 2018, and subsequently extended and improved. Production and Operations Management was established in the1970s as an academic discipline focusing on scientific topics treating the interface between engineering, management, and economics with a special emphasis on financial consequences of decisions in the produc- tion domain. The subject is interdisciplinary in nature and it therefore contains a wide range of topics. The Working Seminar included sessions such as supply chain management, innovation management, general production and operations management, productivity and performance analysis, service management, risk management in production, in- ventory control, scheduling, forecasting, simulation applications, green and reverse logistics, manufacturing strategy, production planning and control, investment and financial planning.

The density of homogeneous phase fluid mixtures for various carbon dioxide (CO2)/organic solvent systems was measured in homogeneous phase. Solvents included cyclohexane (C6H12), methylcyclohexane (C6H11CH3), and ethylbenzene (C6H5C2H5). Density measurements were performed using a high-pressure vibration type density meter equipped with a circulation pump and variable volume viewing cell which guarantee the homogeneity of mixtures. The density was measured at temperatures ranging from 313 K to 353 K and pressures up to 20 MPa, and the CO2 composition varied from (0 to 80) mol%. The obtained experimental data were correlated according to a density equation. The resulting correlation agrees well with the experimental data.

Living organisms are divided into three domains, Bacteria, Eukarya, and Archaea. Comparative studies in the three domains have provided useful information to understand the evolution of the DNA replication machinery. DNA polymerase is the central enzyme of DNA replication. The presence of multiple family B DNA polymerases is unique in Crenarchaeota, as compared with other archaeal phyla, which have a single enzyme each for family B (PolB) and family D (PolD). We analyzed PolB1 and PolB3 in the hyperthermophilic crenarchaeon, Aeropyrum pernix, and found that they are larger proteins than those predicted from the coding regions in our previous study and from public database annotations. The recombinant larger PolBs exhibited the same DNA polymerase activities as previously reported. However, the larger PolB3 showed remarkably higher thermostability, which made this enzyme applicable to PCR. In addition, the high tolerance to salt and heparin suggests that PolB3 will be useful for amplification from the samples with contaminants, and therefore it has a great potential for diagnostic use in the medical and environmental field.

Thermodynamic stability boundaries of the mixed hydrate composed of methane and fluorocyclopentane, chlorocyclopentane, or bromocyclopentane were investigated in a temperature range of (274.17 to 306.19) K and pressures up to 9.93 MPa under the four-phase (hydrate, aqueous, monohalogenated cyclopentane-rich liquid, and gas phases) equilibrium conditions. Also, the crystal structure of the methane + chlorocyclopentane hydrate was determined by means of powder X-ray diffractometry. The each boundary is laid at a pressure lower and a temperature higher than that of the simple methane hydrate. Especially, the methane + fluorocyclopentane hydrate system has the lowest equilibrium pressure among three mixed hydrate systems investigated in the present study. The powder X-ray diffraction patterns reveal that a guest species larger than chrolocyclopentane and smaller than bromocyclopentane is at the border between structure-II and structure-H hydrate formers.

DNA polymerases synthesize new DNA strands according to the template DNA, using deoxynucleotide triphosphates during DNA replication and repair, and are essential to maintain genome integrity in DNA metabolism. In addition, these enzymes are widely used for genetic engineering techniques, including dideoxy-sequencing, PCR, DNA labeling, mutagenesis, and other in vitro experiments. Thermostable DNA polymerases are especially useful for PCR and cycle-sequencing. We propose a powerful strategy using environmental DNA as a genetic resource to investigate the structure-function relationships of the family B DNA polymerases. The region corresponding to the active center of the DNA polymerizing reaction in the structural gene of P. furiosus DNA polymerase I (PolBI) was substituted by PCR fragments amplified from DNAs within soil samples from various locations in Japan. The chimeric pol genes were constructed within the PolBI expression plasmid. The chimeric enzymes thus produced revealed DNA polymerase activities with different properties.

With the national policy reforming, how to decide the power purchasing policy under the uncertain fuel cost becomes the important question for the power grid enterprises in the Chinese electric power supply chain. Usually, the stochastic programming models have often been used for the solution. A new robust optimization model was built and the numerical experiment results were compared with the results from the stochastic programming model. The results show that the robust optimization model is more flexible than the stochastic programming model in the worst situation. Comparing with the result from the stochastic programming, with the small uncertainty range the robust optimization's objective function may have higher value. The solution based on the application of both the robust model and the stochastic model was suggested in response to the required robustness and uncertainty level.

Rexeed was developed by Asahi Kasei Medical using wave-shaped hollow fibers, a full baffle, and a short taper housing to improve dialysate flow. The present study is clarifies improvement in dialysate flow with Rexeed-15 compared with that of a conventional dialyzer. Dialysate flow was evaluated by the pulse-response method. Dialysate pressure and tracer concentration were measured at a blood-side flow rate (QBeta) of 200 ml/min, a dialysate-side flow rate (QD) of 500 ml/min, and a net filtration rate (QF) of 0 ml/min using needles placed in the test dialyzer. Dialyzer performance was evaluated by measuring urea and vitamin B12 clearance at QB = 200 and 400 ml/min, QD = 300-800 ml/min, and QF = 0 ml/min. In the conventional dialyzer, dialysate channeling was observed. In contrast, Rexeed-15 had a uniform dialysate flow. Urea and vitamin B12 clearance with Rexeed-15 was slightly sensitive to QD. The overall mass transfer coefficient for urea with Rexeed-15 was more than 50% higher than that of the conventional dialyzer, indicating the possibility of reduced dialysate usage with Rexeed. Rexeed has a highly optimal dialysate flow, due to the wave-shaped hollow fibers and the new housing, and gives increased clearance for lower-molecular-weight substances.

The family A DNA polymerases from thermophilic bacteria are useful for PCR. The DNA polymerase from Thermus aquaticus (Taq polymerase) was the original enzyme used when practical PCR was developed, and it has remained the standard enzyme for PCR to date. Knowledge gained from structure-function relationship studies of Taq polymerase is applicable to create PCR enzymes with enhanced performance. We collected the deduced amino acid sequences of the regions from motif A to motif C in the family A DNA polymerases from metagenomic sequence data, obtained by sequencing DNAs from microorganisms isolated from various hot spring areas in Japan. The corresponding regions of the polA gene for Taq polymerase were substituted with the metagenomic DNA gene fragments, and various chimeric DNA polymerases were prepared. Based on the properties of these chimeric enzymes and their sequences, we found an insertion sequence that affects the primer extension ability of the family A DNA polymerases. The insertion sequence is located in the finger subdomain, and it may enhance the affinity of the enzyme to DNA. Mutant Taq polymerases with the corresponding 9 amino acid insertion displayed enhanced PCR performance.

2017