Fluid thrust control system

A pure fluid thrust control system is described for a pump-fed, regeneratively cooled liquid propellant rocket engine. A proportional fluid amplifier and a bistable fluid amplifier control overshoot in the starting of the engine and take it to a predetermined thrust. An ejector type pump is provided in the line between the liquid hydrogen rocket nozzle heat exchanger and the turbine driving the fuel pump to aid in bringing the fluid at this point back into the regular system when it is not bypassed. The thrust control system is intended to function in environments too severe for mechanical controls

A primer on cointegration with an application to money and income

Money theory ; Income ; Cointegration

Lattice Gauge Actions for Fixed Topology

We test a set of lattice gauge actions for QCD that suppress small plaquette values and in this way also suppress transitions between topological sectors. This is well suited for simulations in the epsilon-regime and it is expected to help in numerical simulations with dynamical quarks.Comment: 3 pages. Talk presented at Quark Confinement and the Hadron Spectrum VI, Villasimius, Sardinia, Italy, September 21-25, 2004. References adde

A Robust AFPTAS for Online Bin Packing with Polynomial Migration

In this paper we develop general LP and ILP techniques to find an approximate solution with improved objective value close to an existing solution. The task of improving an approximate solution is closely related to a classical theorem of Cook et al. in the sensitivity analysis for LPs and ILPs. This result is often applied in designing robust algorithms for online problems. We apply our new techniques to the online bin packing problem, where it is allowed to reassign a certain number of items, measured by the migration factor. The migration factor is defined by the total size of reassigned items divided by the size of the arriving item. We obtain a robust asymptotic fully polynomial time approximation scheme (AFPTAS) for the online bin packing problem with migration factor bounded by a polynomial in $\frac{1}{\epsilon}$. This answers an open question stated by Epstein and Levin in the affirmative. As a byproduct we prove an approximate variant of the sensitivity theorem by Cook at el. for linear programs

Anomalous temperature evolution of the internal magnetic field distribution in the charge-ordered triangular antiferromagnet AgNiO2

Zero-field muon-spin relaxation measurements of the frustrated triangular quantum magnet AgNiO2 are consistent with a model of charge disproportionation that has been advanced to explain the structural and magnetic properties of this compound. Below an ordering temperature of T_N=19.9(2) K we observe six distinct muon precession frequencies, due to the magnetic order, which can be accounted for with a model describing the probable muon sites. The precession frequencies show an unusual temperature evolution which is suggestive of the separate evolution of two opposing magnetic sublattices.Comment: 4 pages, 3 figure

Bounds for the adiabatic approximation with applications to quantum computation

We present straightforward proofs of estimates used in the adiabatic approximation. The gap dependence is analyzed explicitly. We apply the result to interpolating Hamiltonians of interest in quantum computing.Comment: 15 pages, one figure. Two comments added in Secs. 2 and

Die rol van taalvaardigheid in die verband tussen matrieken universiteitsprestasie van swart eerstejaarstudente

This article highlights some of the factors that play a role in the academic success of black first year students who receive non mother-tongue education in English. Students in the Faculties of Economic and Management Sciences, Natural and Agricultural Sciences, as well as the Humanities/Law at the University of the Free State were involved in the study. It was evident that both matric performance and language ability have predictive value. It was also found that the predictive value of these variables differed between the various faculties (which implies that students’ field of study should be taken into account when decisions regarding access with success is made).Key words: language proficiency, matric performance, academic achievement, non mother-tongue education, black first year students.Hierdie artikel werp lig op sommige faktore wat ’n rol speel in die akademiese prestasie van swart eerstejaarstudente wat nie-moedertaalonderrig in Engels ontvang. Studente in die Fakulteite Ekonomiese en Bestuurswetenskappe, Natuur- en Landbouwetenskappe, asook Geesteswetenskappe/Regte aan die Universiteit van die Vrystaat is by die studie betrek. Dit het geblyk dat beide matriekprestasie en taalvaardigheid voorspellingswaarde het. Verder is ook bevind dat die voorspellingswaarde van hierdie veranderlikes verskil tussen verskillende fakulteite (wat impliseer dat studente se studieveld in ag geneem moet word wanneer besluite rakende toelating met sukses geneem word).Sleutelwoorde: taalvaardigheid; matriekprestasie; akademiese prestasie; niemoedertaalonderrig, swart eerstejaarstudente.The article is in Afrikaans

Comparison between overlap and twisted mass fermions towards the chiral limit

We compare overlap fermions, which are chirally invariant, and Wilson twisted mass fermions in the approach to the chiral limit. Our quenched simulations reveal that with both formulations of lattice fermions pion masses of O(250 MeV) can be reached in practical simulations. Our comparison is done at a fixed lattice spacing a=0.123 fm. Several quantities are measured, such as hadron masses and pseudoscalar decay constants.Comment: Lattice2004(chiral

Interventions for improving health literacy in people with chronic kidney disease

This is the protocol for a review and there is no abstract. The objectives are as follows: This review aims to look at the benefits and harms of interventions for improving health literacy in patients with CKD