40 research outputs found
Radio astronomy Explorer-B in-flight mission control system development effort
A description is given of the development for the Mission Analysis Evaluation and Space Trajectory Operations (MAESTRO) program to be used for the in-flight decision making process during the translunar and lunar orbit adjustment phases of the flight of the Radio Astronomy Explorer-B. THe program serves two functions: performance and evaluation of preflight mission analysis, and in-flight support for the midcourse and lunar insertion command decisions that must be made by the flight director. The topics discussed include: analysis of program and midcourse guidance capabilities; methods for on-line control; printed displays of the MAESTRO program; and in-flight operational logistics and testing
Modification and commissioning of a static high pressure apparatus and phase equilibria measurements for fluorinated hydrocarbons.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.Modifications were undertaken to a static high pressure vapour-liquid equilibrium (VLE)
apparatus described by Naidoo [2004]. The alterations were made to improve the sample
analysis technique. These modifications included the incorporation of the ROLSITM sampling
device into the equilibrium cell, a re-design of the air bath which improved the temperature
profile and further alterations described in the text.
The equipment has an operating temperature range of 278.15 K to 473.15 K and pressure range
of absolute vacuum to 150 bars. The apparatus consisted of an agitated cell in an air-bath. The
uncertainties in the temperature and pressure measurements were ±0.02 K and ±4 kPa
respectively. A Shimadzu Gas Chromatograph, Model 2010 was used for sample analysis.
An initial test of the apparatus was carried out to measure the pure component vapour pressure
data for propane and ethane in the temperature range of 279.24 – 360.18K and the results
concurred with literature data (absolute relative deviation <0.153%)
The experimental procedure used in this study was developed from the technique used by
Ramjugernath [2000], with some minor changes implemented only to achieve some
requirements for problems encountered during the project.
Isothermal binary measurements for the hexafluoroethane (R116) + propane system were used
as test system to investigate the accuracy and reliability of the equipment. Three binary
isotherms were measured at 291.22 K, 296.23 K and 308.21 K. The measured data compared
well with literature data.
Particular attention was placed on the fluorinated hydrocarbons. Specific properties of
fluorinated hydrocarbons give them many applications in industry, such as solvents,
refrigerants, propellants, anaesthetics, etc. Hence, a phase equilibria study of a fluorinated
hydrocarbons system was carried out in this project.
The commissioning of the equipment was successfully undertaken and the equipment was
found to be efficient and reliable. As a consequence measurements were made on the
hexafluoropropylene oxide (HFPO) + ethane system. No data has been previously published in
literature for this system. Measurements were undertaken at five different temperatures, 283.15 K, 290.15 K, 298.15 K, 308.15 K and 318.15 K. The isotherms were chosen in order to have
measurements below and above the critical temperature of ethane, in order to see the transition
at the critical temperature.
The experimental data were modelled via the direct (phi-phi) method. The Peng-Robinson
equation of state was applied, including the Mathias-Copeman alpha correlation with the Wong-
Sandler mixing rules incorporating the NRTL activity coefficient model. Good agreement was
found between the correlated and the measured data
Middle Miocene carbon cycle dynamics : a multi-proxy approach
Coupled inorganic-organic carbon isotopes spanning the Monterey Excursion (16.9-13.5 Ma) suggest changes in the carbon system consistent with the Monterey Hypothesis. Thermal stratification of the oceans is inferred to have increased during the middle Miocene climate transition.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Programmer's manual for the Mission Analysis Evaluation and Space Trajectory Operations program (MAESTRO)
The Mission Analysis Evaluation and Space Trajectory Operations program known as MAESTRO is described. MAESTRO is an all FORTRAN, block style, computer program designed to perform various mission control tasks. This manual is a guide to MAESTRO, providing individuals the capability of modifying the program to suit their needs. Descriptions are presented of each of the subroutines descriptions consist of input/output description, theory, subroutine description, and a flow chart where applicable. The programmer's manual also contains a detailed description of the common blocks, a subroutine cross reference map, and a general description of the program structure
Gerenciamento de serviços de telecomunicações com CORBA e JAVA /
Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico
Third Workshop and Tutorial on Practical Use of Coloured Petri Nets and the CPN Tools, Aarhus, Denmark, August 29-31, 2001
This booklet contains the proceedings of the Third Workshop on Practical Use of Coloured Petri Nets and the CPN Tools, August 29-31, 2001. The workshop is organised by the CPN group at Department of Computer Science, University of Aarhus, Denmark. The papers are also available in electronic form via the web pages: http://www.daimi.au.dk/CPnets/workshop01
Design criteria and concepts for fibrous composite structures Annual report
Design criteria and concepts for fibrous composite materials and composite structures, and failure mechanism
The separation of hexafluoropropylene and hexafluoropropylene oxide using toluene and a novel solvent.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2008.ABSTRACT
PELCHEM, the chemical division of NECSA, produces the fluorocarbon hexafluoropropylene (HFP) onsite.
In 2005 PELCHEM initiated research into the wet oxidation of HFP to produce the higher value
fluorocarbon hexafluoropropylene oxide (HFPO). Although successful in the conversion of HFP to HFPO,
the product stream contained both the product and the unreacted HFP. As a result, PELCHEM contracted
the Thermodynamics Research Unit at the University of KwaZulu-Natal to investigate the separation of
HFP and HFPO.
A solvent selection procedure was used to identifY potential solvents and an initial list of two hundred and
seven candidate solvents compiled. Utilising the UNIFAC group contribution method, the initial list was
narrowed down to thirty solvents using the criterion of selectivity at infinite dilution. Through the
comparison of specific solvent properties such as recoverability, safety, environmental factors and
economic considerations, a final list of ten solvents was generated. The list of ten solvents was proposed to
PELCHEM who identified four solvents for further studies. The work involving the two solvents, toluene
and hexafluoroethane (RI 16), is presented in this dissertation. The solvent toluene has been previously
used by the du Pont company for the separation of HFP and HFPO, while R116 is a novel solvent for this
application. The solvent selection procedure was performed in collaboration with a member of the
Thermodynamics Research Unit, and the work on the remaining two solvents is presented in the
dissertation of (Nelson 2008).
Experimental binary high pressure vapour liquid equilibrium data were measured for the HFP + toluene,
HFPO + toluene, R116 + HFP, and R116 + HFPO systems at two temperatures: 273.15 and 3 13.15 K. Pure
component vapour pressure data for HFPO in the temperature range of 271.90 to 318.20 K were also
measured. The HPVLE measurements were performed at the Thermodynamics Energy and Phase
Equilibria laboratories at Ecoles des Mines de Paris using two experimental techniques and equipment. The
binary systems involving toluene were measured on a static synthetic Pressure Volume Temperature
apparatus equipped with a variable volume cell. The binary systems involving RI16 were measured on a
static analytic apparatus equipped with a Rapid On-line Sampler Injector. None of the systems measured
for this project have been reported in the literature. The four binary systems and the pure component
vapour pressure measurements thus constitute new data sets.
All experimental data were modelled via the direct method using the computer software Thermopack.
Three model combinations were used to represent the data: the Peng-Robinson equation of state with the
Wong-Sandler mixing rules, the Peng-Robinson equation of state with the Modified-Huron-Vidal first
order mixing rules, and the Soave-Redlich-Kwong equation of state with the Wong-Sandler mixing rules.
The Mathias-Copeman alpha function was used in conjunction with the equation of state models, and the NRTL activity coefficient model was incorporated into the mixing rules. Due to time constraints,
experimental data for the binary system HFP + HFPO were not measured. Data for this system was
predicted at two temperatures, 273.15 and 313.15 K, via the PSRK-UNIFAC method. The critical line for
the supercritical systems R116 + HFP and R116 + HFPO were calculated in Thermopack.
PELCHEM required a commercial grade HFPO product stream of purity greater than 99 % (mole), and a
purified HFP product stream of purity greater than 95 % for the recycle and conversion of HFP into HFPO.
Using the regressed experimental high pressure vapour liquid equilibrium data, two preliminary separation
processes were designed in Aspen Plus to achieve these objectives. The first scheme involved toluene and
utilised the process of extractive distillation with toluene introduced as a liquid solvent. The toluene bonded
to the HFP and was removed as a bottoms product which allowed a purified HFPO stream to be recovered
as a distillate. The second scheme involved RI16 and utilised the process of gas stripping, with a liquid
mixture of HFP and HFPO contacted with a gaseous stream of R116. The R116 removed the HFP from the
liquid mixture, resulting in a purified HFPO stream. The toluene process resulted in an overall HFPO
product recovery of 98.46 % and HFPO product purity of99.88 % (mole). The RI16 process resulted in an
overall HFPO product recovery of96.57 % and HFPO product purity of99.71 %. For the component HFP,
the toluene process resulted in an overall HFP product recovery of 99.42 % and product purity of96.41 %.
The RI16 process resulted in an overall product recovery of99.36 % and product purity of93.45 %.
From a comparison of the preliminary design of the separation processes on the basis of patent issues,
performance, and other miscellaneous factors, it was concluded that the RI16 process compared favourably
to the process involving the solvent toluene. The preliminary process designs were presented to PELCHEM
in 2007, and pending further experimental work PELCHEM plans to patent the RI16 separation process
Annual report of the town of Harrisville, for the year ending December 31, 2006.
This is an annual report containing vital statistics for a town/city in the state of New Hampshire