Hydrogen production by flue gas through sulfur–iodine thermochemical process: Economic and energy evaluation

The use of low quality fossil fuel with high sulfur content is becoming more frequent and probably will play a very important role in the future, due to the depletion of reserves.     

An empirical study of service postponement: locating the push–pull boundary

The purpose of this paper is to determine if service firms can profitably perform postponement. We develop a general model to identify the optimal location of the push–pull boundary, or extent of postponement. While previous literature discusses the benefit of applying postponement to the service industry this is the first paper to-date that mathematically models the benefit of service postponement. This paper illustrates how service companies can balance the trade-off between increased responsiveness and increased costs. The single-stage newsvendor model is iteratively applied to each stage of the service process to determine the optimal level of postponement. Two examples demonstrate the value of postponement and the impact of changes in service characteristics are investigated. Finally, this paper provides guidance for service industry professionals on policy-level decisions and applications of postponement.     

Energy and economic assessment of an industrial plant for the hydrogen production by water-splitting through the sulfur-iodine thermochemical cycle powered by concentrated solar energy

The faster and faster global growth of energy consumption generates serious problems on its supply and about the pollution that may result. Through the use of thermochemical cycles it is possible to use renewable energy to produce hydrogen from water, with the dual purpose of having an unlimited source of energy without producing greenhouse gases.     

Redundancy in logic II: 2CNF and Horn propositional formulae

We report results about the redundancy of formulae in 2CNF form. In particular, we give a slight improvement over the trivial redundancy algorithm and give some complexity results about some problems related to finding Irredundant Equivalent Subsets (i.e.s.) of 2CNF formulae. The problems of checking whether a 2CNF formula has a unique i.e.s. and checking whether a clause in is all its i.e.s.'s are polynomial. Checking whether a 2CNF formula has an i.e.s. of a given size and checking whether a clause is in some i.e.s.'s of a 2CNF formula are polynomial or NP-complete depending on whether the formula is cyclic. Some results about Horn formulae are also reported.     

A longitudinal analysis of dysfunctional TMJ pathology: an assessment of a sample of patients undergoing nonsurgical therapy

One the different interpretation of the pathological and clinical evolution of TMJ dysfunctions, the most-common of these pathologies is the condyle-disk uncoordination. This study analyzes the evolution of the treatment on the sample of patients affected by TMJ dysfunction and examined at the maxillo-facial department of the University of Rome "La Sapienza". After the TMJ dysfunction has been diagnosed the patients were informed of the individual therapeutic program which consisted of a temporary and definitive occlusal therapy. The aim of this scientific work is to control the efficiency within this therapeutic program in relation to the uncoordination of TMJ. In order to validate this approach the study was compared with another that considered the evolution of TMJ pathology in patients examined at the first diagnostic, visit but who had not undergone any treatment.     

Analytics Capabilities and the Decision to Invest in Analytics

The increasing use of data-driven decision making and big data is leading organizations to invest in analytics software and services. However, little is known about the type of analytics capabilities within IT that are required and whether there is a common progression or development model of analytics capabilities. Also unknown is how the level of analytics capabilities and other factors influence a firm’s decision to invest in analytics. The purpose of this research is to explore the relationships between levels of distinct analytics capabilities and to understand how they and other factors influence the analytics investment decision. The findings suggest that there is a distinct progression in the development of analytics capabilities, and that firm size is associated with increased capability. The results suggest that firms more likely to invest in analytics have higher current levels of specific analytics capabilities, are larger, and are located in less-competitive industries.     

Analysis of facility protection strategies against an uncertain number of attacks: The stochastic R-interdiction median problem with fortification

We present the Stochastic R-Interdiction Median Problem with Fortification (S-RIMF). This model optimally allocates defensive resources among facilities to minimize the worst-case impact of an intentional disruption. Since the extent of terrorist attacks and malicious actions is uncertain, the problem deals with a random number of possible losses. A max-covering type formulation for the S-RIMF is developed. Since the problem size grows very rapidly with the problem inputs, we propose pre-processing techniques based on the computation of valid lower and upper bounds to expedite the solution of instances of realistic size. We also present heuristic approaches based on heuristic concentration-type rules. The heuristics are able to find an optimal solution for almost all the problem instances considered. Extensive computational testing shows that both the optimal algorithm and the heuristics are very successful at solving the problem. Finally, a discussion of the importance of recognizing the stochastic nature of the number of possible attacks is provided.     

Correlating the chemical and physical properties of a set of heavy oils from around the world

Variations in the viscosity and other physical properties of heavy oils are poorly understood. The viscosities measured for different heavy oils can vary by orders of magnitude even at the same API gravity, which is the standard metric for lighter oils. Heavy oils are viscoelastic materials, and the shear modulus and the viscosity are coupled. Understanding what controls heavy oil viscosity will provide insight into what controls heavy oil shear modulus. Therefore, using rheology, ultrasonic measurements and molecular beam mass spectroscopy (MBMS) the physical and chemical properties of seven heavy oils from around the globe are explored. The viscoelastic nature of the oils is quantified as a function of temperature. Overall, the heavy oil samples show little correlation between the viscosity or shear modulus and the API gravity, separate resin content or separate asphaltene content as measured from SARA analysis. However, the total resin plus asphaltene content collapses the viscosity and modulus values to provide empirical relations between these quantities. Also, a partial least squares regression analysis provides tight correlations for the chemical signatures from the MBMS. The rapid and quantitative nature of the MBMS make it an attractive substitute for the inconsistencies endemic to SARA analysis.     

Further relationships between several types of multiparametric sensitivity

The study of sensitivity carried out in previous work¹ is resumed and generalized, both with regard to relationships with other sensitivity expressions and with regard to the extension of the study to the 3rd-degree polynomials that appear in the transfer functions realized by active networks with nonideal operational amplifiers. A study is made of the relationships between the various sensitivity expressions with respect both to the polynomial coefficients of the transfer function and to the physical parameters of the circuit, to show the possibility of measuring some forms of sensitivity hitherto defined analytically. Lastly, emphasis is placed on the difference between the sensitivity of the transfer function in complex form and that of its modulus and phase with respect to the polynomial coefficients, and an attempt is made to relate them, with reference to other studies that have recently appeared in the technical literature^1,3.