Requirements Engineering f��r Product Service Systems

In recent years, manufacturing companies and service providers have moved towards offering customer-specific problem solutions. These integrated bundles usually consist of hardware, software, and service components and are called product service systems (PSS) or hybrid products. Since the success of the resulting solution depends on the understanding of all requirements, requirements engineering (RE) has become a key factor. The article analyzes the state of the art of RE for PSS based on an extensive literature review in the domains of product-, software-, and service engineering. For this, criteria are derived from the characteristics of PSS and from the task area of RE in the life cycle of PSS. Based on these criteria we analyze the most established RE approaches for their suitability for PSS. An important finding is that integrated/interdisciplinary approaches for RE are missing. Moreover, the maturity of RE approaches in the three domains varies significantly. All analyzed approaches heavily rely on concepts and solution characteristics of their own domain so that a transfer to other domains is hardly possible. This literature review lays the foundation for successful RE for PSS and especially for future research aiming at combining and integrating RE approaches and models of product-, software-, and service engineering. Such requirement models could connect concepts of single domains and enable an integrated and seamless RE for PSS.     

G Protein-Coupled Receptors Regulated by Membrane Potential

G protein-coupled receptors (GPCRs) are involved in a vast majority of signal transduction processes. Although they span the cell membrane, they have not been considered to be regulated by the membrane potential. Numerous studies over the last two decades have demonstrated that several GPCRs, including muscarinic, adrenergic, dopaminergic, and glutamatergic receptors, are voltage regulated. Following these observations, an effort was made to elucidate the molecular basis for this regulatory effect. In this review, we will describe the advances in understanding the voltage dependence of GPCRs, the suggested molecular mechanisms that underlie this phenomenon, and the possible physiological roles that it may play.     

Increasing the rated capacity of power units installed at Russian nuclear power stations equipped with VVER-1000 reactors

Safe operation of the Balakovo nuclear power station’s Unit 2 built around a VVER-1000 reactor at a thermal power output of 3120 MW with meeting of the safety criteria and compliance with the requirements of existing regulatory documents is substantiated. Results from measurements of process parameters at a power output equal to 104% of its nominal value are presented.     

Application of the system of automated monitoring of the residual service life for the solution of the problems of operation of nuclear power plants with water-cooled water-moderated reactors

We generalize the software implementation experience for a SAKOR-M system of automated monitoring of the residual service life operating as a component of the systems of diagnostics of residual service life. The SAKOR-320 system introduced at the second power-generating block of the Rostovskaya nuclear power plant additionally includes the surface resistance thermometers, solves the inverse problem, takes into account the actual displacements of steam generators, computes the degree of fatigue growth of the defects, and evaluates the ultimate states according to the criteria of leak prior to failure.     

Use of methods of solving inverse problems of heat conduction to establish the coefficient of heat transfer in jet cooling

The problem of determining the coefficient of heat transfer is analyzed as an inverse problem for the heat-conduction equation. The results of a calculation of the coefficient of heat transfer on the basis of experimental data on the jet cooling of metal plates are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 5, pp. 903–909, May, 1978.     

Development of a root feeding system based on a fiber ion-exchange substrate for space plant growth chamber "Vitacycle"

Selecting a plant root nutrient delivery system is one of the key aspects of designing root modules for space plant growth chambers. This article examines a number of the nutrient delivery systems and shows the most suitable technique for providing nutrients to roots in microgravity, which to date are ion-exchange artificial soils. In addition, this article characterizes the ion composition and hydrophysical parameters of a new Russian artificial ion charged fiber substrate, BIONA-V3. The BIONA-V3 substrate is comprised of ion-exchange resin fibers. The experimental data concerning the effects of anionic and cationic components on plant biomass is presented. Preliminary experiments with BIONA-V3 showed that 1 kg of dry BIONA-V3 produces up to 2.4 kg (fresh mass) of cabbage leaf or 180 g of dry plant mass per 1 dm3 of the substrate. Therefore, the root zone volume can be as small as 120 cm3 per plant. Further optimizing the nutrient composition of the resin fibers can increase space plant growth chamber productivity.