Thermoeconomic Analysis of Vapour Compression Refrigeration System With Dedicated Subcooler for High-Temperature Lift Applications

A single-stage vapour compression refrigeration system becomes inefficient and impractical when the temperature lift between the evaporator and the condenser becomes large. Under the high temerature lift, different losses in the system increase and more refrigerant vapour is formed at the end of the throttling process. The authors have attempted to analyze a vapour compression refrigeration system with dedicated subcooler for high-temperature lift applications using R134a in the main cycle and four low GWP refrigerants in the subcooler cycle. The modelling of the proposed system has been carried out in EES considering the energy, exergy and economic aspects for the simulation of the system. The predicted results show that the use of the proposed system is more beneficial from both performance and economy point of view for high temperature lift. Nearly 27% improvement in both energetic and exergetic performances are noted whereas cost is reduced by 2% when the proposed system is used instead of a typical refrigeration system. Finally, the present investigation concludes that the use of refrigerant R1234ze is much efficient than the other investigated refrigerants due to its low GWP and compressor discharge temperature, in spite of achieving better thermo-economic performances using R152a as subcooler refrigerant.

The Records Management as a Valuable Asset for Corporate Governance

The main goal of this study is to demonstrate how a management records system increase the level of organizational governance. It also shows how corporate governance interacts with record managers. With that purpose, a descriptive analysis of a qualitative, exploratory, and facetted nature is carried out based on literature and records management standards, with emphasis on the standard ISO 30301:2019 edited on records management (RM). In addition, a comparative analysis of the principles and critical factors of governance is carried out in order to compare them and systematize relations with those of the MSR. As a result, the authors seek to identify the determining critical factors and relationships, both with the most prominent elements as components of governance, and with their basic principles: openness, participation, responsibility, efficiency, and consistency. The results of the study highlight the close relationship between them and show a greater presence in the ISO 30301 standard.

Application of the Modern Stationary Workholding Systems for Increase Capacity and Quality of Non-Rigid Aircraft Parts

Review of results experimental, production tests and features of machining forging workpiece of part type «chassis beam» from aluminum alloy V93pchT3 with significant deformations during milling process on SCHUNK VERO-S AVIATION system. Increase of production capacity on 2.9 times and significant better quality, geometrical properties if compare with conventional fixation by clamps.

Planning from the Bottom Up

This chapter recounts how New York City Transit Authority rail service planners Peter Cafiero, Chuck Kirchner, Glenn Lunden, and Jon Melnick resurrected the Second Avenue subway in 1988. Even though the Transit Authority was in the early stages of its 1987–91 capital program, the planners' bosses wanted to start getting ready for the next program, which would run from 1992 to 1996. The first step would be to create a document that assessed the authority's long-term needs and identified projects that would rehabilitate the subway system, increase ridership, improve productivity, and expand system capacity. One proposal the planners wrote to address the Lexington Avenue's problems was an idea that the MTA planner Bob Olmsted had first championed in 1975—a Second Avenue subway north of 63rd Street. As the Second Avenue subway proposal moved up the Transit Authority hierarchy, the authority's president, David Gunn, agreed that the time was right to begin thinking about expanding the subway system. Before he could devote significant resources to advancing the Second Avenue subway, however, it would have to compete with other potential megaprojects under discussion at the MTA's agencies.