Developing Cross Section Sets for Fluorocarbon Etchants

Successful modeling of plasmas used in materials processing depends on knowledge of a variety of collision cross sections and reaction rates, both within the plasma and at the surface. Electron-molecule collision cross sections are especially important, affecting both electron transport and the generation of reactive fragments by dissociation and ionization. Because the supply of cross section data is small and measurements are difficult, computational approaches may make a valuable contribution, provided they can cope with the significant challenges posed. In particular, a computational method must deal with the full complexity of low-energy electron-molecule interactions, must treat polyatomic molecules, and must be capable of computing cross sections for electronic excitation. These requirements imply that the method will be numerically intensive and thus must exploit high-performance computers to be practical. We have developed an ab initio computational method, the Schwinger multichannel (SMC) method, that possesses the characteristics just described, and we have applied it to compute cross sections for a variety of molecules, with particular emphasis on fluorocarbon and hydrofluorocarbon etchants used in the semiconductor industry. A key aspect of this work has been an awareness that cross section sets, validated when possible against swarm data, are more useful than individual cross sections. To develop such sets, cross section calculations must be integrated within a focused collaborative effort. Here we describe electron cross section calculations carried out within the context of such a focused effort, with emphasis on fluorinated hydrocarbons including CHF3 (trifluoromethane), c-C_(4)F_(8) (octafluorocyclobutane), and C_(2)F_(4) (tetrafluoroethene)

Substantial Shifts in Supreme Court Health Law Jurisprudence

President Trump’s nomination of jurist Brett Kavanaugh to the U.S. Supreme Court presents significant, potential changes on health law and policy issues. If confirmed by the U.S. Senate, Kavanaugh’s approaches as a federal appellate court judge and scholar could literally shift the Court’s balance on consequential health policies. Judge Kavanaugh has disavowed broad discretion for federal agency authorities, cast significant doubts on the constitutionality of the Affordable Care Act, and narrowly interpreted reproductive rights (most notably abortion services). He has supported gun rights pursuant to the Second Amendment beyond U.S. Supreme Court recent interpretations. His varying positions related to consumer protections, environmental regulation, and antidiscrimination protections lend further to major concerns on the maintenance of settled positions of the Court on these and other critical health issues

Scaling Up Climate Action to Achieve the Sustainable Development Goals

In 2015, UNDP released its first infographic report that presented the breadth and depth of our support on climate change over the past two decades. That report emphasized successes and noted the opportunities that climate action presents for countries as they transition their economies towards zero-carbon and climate-resilient sustainable development.This year, as countries begin to take concrete action to deliver on their national climate goals, we are pleased to release an updated report of UNDP's climate change work. New, in this report, is a special focus on the linkages between climate change and sustainable development. Specifically, the report highlights the importance of climate action in delivering on the SDGs and provides examples of UNDP's on-going work on the ground towards this end. The report also presents UNDP's commitment to scale up climate change action in order to deliver on the ambitious agenda that countries agreed to in 2015." – Magdy Martinez-Solima

Modeling and Testing of an R-23/R-134a Mixed Refrigerant System for Low Temperature Refrigeration

Low temperature refrigeration storage equipment in the biotechnology industry typically uses cascade refrigeration to achieve evaporating temperatures of -80 °C (-112 °F) or below. Current systems utilize multiple compressors leading to high energy consumption. Equipment operating costs contribute significantly to the total operating costs of biotechnology companies and therefore motivate the development of more efficient alternatives for low temperature refrigeration. This paper describes a single compressor R-23/R-134a mixed refrigerant cycle that has been designed to extract a load of 0.256 kW (873.5 Btu/hr) from a conditioned space at -80 °C (-112 °F). The designed system compresses a mixture of the gaseous refrigerants to a high pressure and then condenses the R-134a in a water-cooled separator while the R-23 remains in vapor phase. The stream of liquid R-134a is expanded to the suction pressure and is used to condense the R-23 that remains in vapor phase, operating much like an inter-stage heat exchanger in a cascade cycle. The condensed stream of R-23 then expands to the suction pressure and enters a low-temperature evaporator, where it absorbs energy from the load. A model of the cycle is developed based upon first and second law principles of thermodynamics and used to refine the design of a mixed refrigerant test apparatus. Theoretical analysis of the prototype system predicts that it will reach an evaporating temperature of -78.6 °C (-109.5 °F) when it operates with a mixture of 33.4% R-23 and 66.6% R-134a by mass. In experiments conducted using the same condensing temperature and mixture composition the mixed refrigerant apparatus reached an evaporating temperature of -75.0 °C (-103 °F), corresponding closely to the predicted temperature of -78.6 °C (-109.5 °F). To reach the desired evaporating temperature of -80 °C (-112 °F) the refrigerant mixture must be altered to increase the amount of R-23

Experimental assessment of R134a and its lower GWP alternative R513A

Lower GWP refrigerants are essential to mitigate the impact of refrigeration systems on climate change. HFO/HFC mixtures are currently considered to replace HFCs in refrigeration and air conditioning systems. The aim of this paper is to present the main operating and performance differences between R513A (GWP of 573) and R134a (GWP of 1300), the most used refrigerants for medium evaporation temperature refrigeration systems and mobile air conditioners. To perform the experimental comparison, 36 tests are carried out with each refrigerant at evaporating temperatures between −15 and 12.5°C and condensing temperatures between 25 and 35°C. The conclusion of the experimental comparison is that R513A can substitute R134a with only a thermostatic expansion valve adjustment, achieving better performance and higher cooling capacity. The discharge temperature of R513A is always lower than that of R134a.The authors thankfully acknowledge the Ministry of Education, Culture and Sports, Spain for supporting this work through “Becas y Contratos de Formación de Profesorado Universitario del Programa Nacional de Formación de Recursos Humanos de Investigación del ejercicio 2012 (Grant number FPU12/02841)” and “Ayudas complementarias para beneficiarios de ayudas (FPU): Estancias Breves. Convocatoria 2015 (Grant number EST15/00154)”. This research is also done within the Effsys Expand P08 project that is funded by the Swedish Refrigeration Cooperation Foundation, KYS and Swedish Energy Agency with the support of Bosch Thermoteknik AB, Danfoss Värmepumpar AB, Nibe AB, Nowab, Svensk Energi & Kylanalys AB and Svenska Kyltekniska Föreningen

Innovation and diffusion of clean/green technology: Can patent commons help?

This paper explores the characteristics of 238 patents on 94 “inventions” contributed by major multinational innovators to the “Eco-Patent Commons”, which provides royalty-free access to third parties to patented climate change related innovations. By comparing the pledged patents to other patents in the same technologies or held by the same multinationals, we investigate the motives of the contributing firms as well as the potential for such commons to encourage innovation and diffusion of climate change related technologies. This study, therefore, indirectly provides evidence on the role of patents in the development and diffusion of green technologies. More generally, the paper sheds light on the performance of hybrid forms of knowledge management that combine open innovation and patenting.patent commons, green technology, eco-aptents, diffusion, climate change

The right way to reform the EU emissions trading system: Alternatives to the market stability reserve

In the light of persistently low prices for allowances, there is much debate about reforming the EU emissions trading system. Based on a proposal of the European Commission, the EU plans to introduce the so called Market Stability Reserve in 2019: a mechanism that regulates the amount of allowances within the market by temporarily taking some of the allowances into a reserve. The Commission thereby aims at reducing the surplus and securing a higher market price for allowances. An alternative reform proposal is the introduction of a minimum price. This RWI position puts forward a third alternative: retaining the emissions trading system in its original form and reducing the surplus by a one-time adjustment. In 2014, 900 million allowances from the years 2014 to 2016 were back-loaded to be auctioned in the years 2019 and 2020. Instead, these allowances should be deleted. Furthermore, if necessary, the amount of allowances could be constantly decreased by reducing the cap more strongly than planned. Compared with the other reform options, retaining the emissions trading system in its original form has two major advantages: first, politically driven interventions are minimized and, second, free market prices exhibit a stabilizing effect for fluctuations caused by the business cycle

Changing trends and emissions of hydrochlorofluorocarbons (HCFCs) and their hydrofluorocarbon (HFCs) replacements

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