A Practical Tool for Evaluating Refrigeration Systems Using R-134a

Evaluation of HFO-1234yf as a Potential Replacement for R-134a in Refrigeration Applications

In response to concerns about the contribution of fluorocarbon refrigerants to global climate change, a new, more environmentally sustainable, refrigerant molecule has been developed and is being evaluated. This new molecule is the hydrofluoroolefin 2,3,3,3,-tetrafluoroprop-1-ene, or HFO-1234yf. The molecule has been shown to be stable inside refrigeration equipment, but to quickly decompose if...

A practical algorithm for [r, s, t]-coloring of graph

Coloring graphs is one of important and frequently used topics in diverse sciences. In the majority of the articles, it is intended to find a proper bound for vertex coloring, edge coloring or total coloring in the graph. Although it is important to find a proper algorithm for graph coloring, it is hard and time-consuming too. In this paper, a new algorithm for vertex coloring, edge coloring an...

Emission of Refrigerant R-134a from Mobile Air-Conditioning Systems

A Thermodynamic Property Model for the R-134a/245fa Mixture

A thermodynamic property model explicit in the Helmholtz energy is presented for the R-134a/245fa mixtures. A multi-fluid approximation based on pure-fluid Helmholtz energy equations of state forms the basis of the property model. The Helmholtz energy of the mixture is expressed as the sum of the ideal gas contribution, the compressibility contribution (real fluid contribution), and the contrib...

MACOM - A Tool for Evaluating Communication Systems

MACOM (Markovian Analysis of Communication Systems) is a software tool for the model based performance evaluation of (parts of) communication systems. Models are speciied by graphical interactive means, model solution is performed by using numerical techniques for Markovian models. Compared to purely analytic approaches, this approach allows for a considerably enhanced model world. Concepts cov...