The water-cryogen heat exchanger

Heat exchanger, using water as heat medium, converts liquid hydrogen to gaseous hydrogen at a very high rate. Possible applications include treatment of liquified natural gas in cities to bring the gas on-line quickly, conversion of liquid oxygen and liquid nitrogen for steel mills, and high volume inert purging

Derivation of the Blackbody Radiation Spectrum from a Natural Maximum-Entropy Principle Involving Casimir Energies and Zero-Point Radiation

By numerical calculation, the Planck spectrum with zero-point radiation is shown to satisfy a natural maximum-entropy principle whereas alternative choices of spectra do not. Specifically, if we consider a set of conducting-walled boxes, each with a partition placed at a different location in the box, so that across the collection of boxes the partitions are uniformly spaced across the volume, then the Planck spectrum correspond to that spectrum of random radiation (having constant energy kT per normal mode at low frequencies and zero-point energy (1/2)hw per normal mode at high frequencies) which gives maximum uniformity across the collection of boxes for the radiation energy per box. The analysis involves Casimir energies and zero-point radiation which do not usually appear in thermodynamic analyses. For simplicity, the analysis is presented for waves in one space dimension.Comment: 11 page

Control of erythroid differentiation: asynchronous expression of the anion transporter and the peripheral components of the membrane skeleton in AEV- and S13-transformed cells

Chicken erythroblasts transformed with avian erythroblastosis virus or S13 virus provide suitable model systems with which to analyze the maturation of immature erythroblasts into erythrocytes. The transformed cells are blocked in differentiation at around the colony-forming unit- erythroid stage of development but can be induced to differentiate in vitro. Analysis of the expression and assembly of components of the membrane skeleton indicates that these cells simultaneously synthesize alpha-spectrin, beta-spectrin, ankyrin, and protein 4.1 at levels that are comparable to those of mature erythroblasts. However, they do not express any detectable amounts of anion transporter. The peripheral membrane skeleton components assemble transiently and are subsequently rapidly catabolized, resulting in 20-40-fold lower steady-state levels than are found in maturing erythrocytes. Upon spontaneous or chemically induced terminal differentiation of these cells expression of the anion transporter is initiated with a concommitant increase in the steady- state levels of the peripheral membrane-skeletal components. These results suggest that during erythropoiesis, expression of the peripheral components of the membrane skeleton is initiated earlier than that of the anion transporter. Furthermore, they point a key role for the anion transporter in conferring long-term stability to the assembled erythroid membrane skeleton during terminal differentiation

Some Heuristic Semiclassical Derivations of the Planck Length, the Hawking Effect and the Unruh Effect

The formulae for Planck length, Hawking temperature and Unruh-Davies temperature are derived by using only laws of classical physics together with the Heisenberg principle. Besides, it is shown how the Hawking relation can be deduced from the Unruh relation by means of the principle of equivalence; the deep link between Hawking effect and Unruh effect is in this way clarified.Comment: LaTex file, 6 pages, no figure

“We Give Way:” 6 Narratives of the Academic Negotiation Between English and Afrikaans at The University of Stellenbosch

The negotiations between the African National Congress (ANC) and the National Party in 1992 led to the creation of South Africa’s eleven national languages including English and Afrikaans. This paper discusses the intricate relationship between these two languages at the University of Stellenbosch. This project attempts to understand how undergraduate and postgraduate students have negotiated the rise of English as a universal academic language and the maintenance of Afrikaans as Stellenbosch’s core language of instruction. The project works to determine how students view the changes to the policy and how those changes affect them, looking particularly at the effect of dual-medium instruction between English and Afrikaans. To give context to the current language debate occurring at the University of Stellenbosch, I give a brief summary of South African language policy at the tertiary level and at the University of Stellenbosch. Then after analyzing data gathered in interviews with undergraduate and postgraduate students, this paper examines the effect of bilingual instruction on the students and how they view the growing pressure on the University of Stellenbosch to Anglicize its courses. The findings of this project have determined that language policy at the University of Stellenbosch is much different from the language practices at the institution. In fact, the language practices of some undergraduate and postgraduate students actually contradict the current policies put in place by the University and the South African government. This study has shown that language practice at the University is fueled by the international demand for English speakers while competing with the deep-rooted Afrikaans tradition

Prostitution During the Pandemic: Findings Show Need for Nordic Model

The impact of COVID-19 on sexually exploited individuals provides an opportunity to advance the Nordic Model approach and create lasting change. Although subject to gender-based violence and denied safety net services, commercially sexually exploited women are seldom seen as a “vulnerable” group in the pandemic. Interviews from social service agencies in Seattle, Washington show women are experiencing more physical and sexual violence from sex buyers and women who have exited prostitution are finding their stability and security in jeopardy. Advocates can make the case to address disparities with safety net guarantees and structural change with the adoption of the Nordic Model

Multiple Raters in Survey-Based Operations Management Research: A Review and Tutorial

Research in the area of operations strategy has made significant progress during the past decade in terms of quantity of articles published, as well as the quality of these articles. Recent studies have examined the published literature base and determined that, in general, the field has progressed beyond an exploratory stage to a point where there is a core set of basic terminology and models. Concurrent with the formation and solidification of a core terminology, there is an increasing emphasis on developing and employing a set of reliable, valid, and reproducible methods for conducting research on operations strategy. We provide a review of common methods for assessing the degree of reliability and agreement of the responses provided by multiple raters within a given organization to a set of qualitative questions. In particular, we examine four methods of determining whether there is evidence of disagreement or bias between multiple raters within a single organization in a mail survey

Energy properness and Sasakian-Einstein metrics

In this paper, we show that the existence of Sasakian-Einstein metrics is closely related to the properness of corresponding energy functionals. Under the condition that admitting no nontrivial Hamiltonian holomorphic vector field, we prove that the existence of Sasakian-Einstein metric implies a Moser-Trudinger type inequality. At the end of this paper, we also obtain a Miyaoka-Yau type inequality in Sasakian geometry.Comment: 27 page