Resource Type

Degree Department

8,984 Matching Results

Results open in a new window/tab.

101-SY Hydrogen Safety Project chemical analysis support: Window ``C`` total organic carbon analysis (open access)

101-SY Hydrogen Safety Project chemical analysis support: Window ``C`` total organic carbon analysis

Core samples taken from Hanford double-shell waste tank 101-SY during Window ``C`` (after the May 1991 gas release event) were analyzed for total organic carbon by the staff of the Analytical Chemistry Laboratory at Pacific Northwest Laboratory. The procedure uses the oxidation/extraction method of hot acid persulfate oxidation. Evolved CO{sub 2} is measured by a UIC Coulometric Carbon Analyzer coulometry detector. Samples are acidified with heated sulfuric acid to drive off all inorganic carbonate carbon as CO{sub 2}. Excess potassium persulfate oxidant, along with a silver catalyst, is then added to the heated sulfuric acid solution. All organic carbon is oxidized to CO{sub 2}, swept away by the carrier gas to the Coulometrics Analyzer, and the results calculated and displayed directly as {mu}g carbon titrated.
Date: January 1, 1992
Creator: Gillespie, B. M.; Stromatt, R. W.; Baldwin, D. L. & Hoopes, F. V.
System: The UNT Digital Library
101-SY Hydrogen Safety Project chemical analysis support: Window C'' total organic carbon analysis (open access)

101-SY Hydrogen Safety Project chemical analysis support: Window C'' total organic carbon analysis

Core samples taken from Hanford double-shell waste tank 101-SY during Window C'' (after the May 1991 gas release event) were analyzed for total organic carbon by the staff of the Analytical Chemistry Laboratory at Pacific Northwest Laboratory. The procedure uses the oxidation/extraction method of hot acid persulfate oxidation. Evolved CO{sub 2} is measured by a UIC Coulometric Carbon Analyzer coulometry detector. Samples are acidified with heated sulfuric acid to drive off all inorganic carbonate carbon as CO{sub 2}. Excess potassium persulfate oxidant, along with a silver catalyst, is then added to the heated sulfuric acid solution. All organic carbon is oxidized to CO{sub 2}, swept away by the carrier gas to the Coulometrics Analyzer, and the results calculated and displayed directly as {mu}g carbon titrated.
Date: January 1, 1992
Creator: Gillespie, B. M.; Stromatt, R. W.; Baldwin, D. L. & Hoopes, F. V.
System: The UNT Digital Library
500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NO[sub x]) emissions from coal-fired boilers (open access)

500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NO[sub x]) emissions from coal-fired boilers

The project provides a stepwise retrofit of an advanced overfire air (AOFA) system followed by low NO[sub x] burners (LNB). During each test phase of the project, diagnostic, performance, long-term, and verification testing will be performed. These tests are used to quantify the NO[sub x] reductions of each technology and evaluate the effects of those reductions on other combustion parameters such as particulatecharacteristics and boiler efficiency. Baseline, AOFA, and LNB without AOFA test segments have been completed. Analysis of the 94 days of LNB long-term data collected show the full-load NO[sub x] emission levels to be approximately 0.65 lb/MBtu. Flyash LOI values for the LNB configuration are approximately 8 percent at full-load. Corresponding values for the AOFA configuration are 0.94 lb/MBtu and approximately 10 percent. Abbreviated diagnostic tests for the LNB+AOFA configuration indicate that at 500 MWe, NO[sub x] emissions are approximately 0.55 lb/MBtu with corresponding flyash LOI values of approximately 11 percent. For comparison, the long-term full-load, baseline NO[sub x] emission level was approximately 1.24 lb/MBtu at 5.2 percent LOI. Comprehensive testing of the LNB+AOFA configuration will be performed when the stackparticulate emissions issue is resolved. Testing of a process optimization package on Plant Hammond Unit 4 was performed …
Date: January 1, 1992
Creator: unknown
System: The UNT Digital Library
1992 Columbia River Salmon Flow Measures Options Analysis/EIS. (open access)

1992 Columbia River Salmon Flow Measures Options Analysis/EIS.

This Options Analysis/Environmental Impact Statement (OA/EIS) identifies, presents effects of, and evaluates the potential options for changing instream flow levels in efforts to increase salmon populations in the lower Columbia and Snake rivers. The potential actions would be implemented during 1992 to benefit juvenile and adult salmon during migration through eight run-of-river reservoirs. The Corps of Engineers (Corps) prepared this document in cooperation with the Bonneville Power Administration and the Bureau of Reclamation. The US Fish and Wildlife Service (FSWS) is a participating agency. The text and appendices of the document describe the characteristics of 10 Federal projects and one private water development project in the Columbia River drainage basin. Present and potential operation of these projects and their effects on the salmon that spawn and rear in the Columbia and Snake River System are presented. The life history, status, and response of Pacific salmon to current environmental conditions are described.
Date: January 1, 1992
Creator: unknown
System: The UNT Digital Library
1992 Columbia River Salmon Flow Measures Options Analysis/EIS : Appendices. (open access)

1992 Columbia River Salmon Flow Measures Options Analysis/EIS : Appendices.

This Options Analysis/Environmental Impact Statement (OA/EIS) identifies, presents effects of, and evaluates the potential options for changing instream flow levels in efforts to increase salmon populations in the lower Columbia and Snake rivers. The potential actions would be implemented during 1992 to benefit juvenile and adult salmon during migration through eight run-of-river reservoirs. The Corps of Engineers (Corps) prepared this document in cooperation with the Bonneville Power Administration and the Bureau of Reclamation. The US Fish and Wildlife Service (FWS) is a participating agency. The text and appendices of the document describe the characteristics of 10 Federal projects and one private water development project in the Columbia River drainage basin. Present and potential operation of these projects and their effects on the salmon that spawn and rear in the Columbia and Snake River System are presented. The life history, status, and response of Pacific salmon to current environmental conditions are described. The document concludes with an evaluation of the potential effects that could result from implementing proposed actions. The conclusions are based on evaluation of existing data, utilization of numerical models, and application of logical inference. This volume contains the appendices.
Date: January 1, 1992
Creator: unknown
System: The UNT Digital Library
1992 Fact Sheet, North Texas Institute for Educators on the Visual Arts (open access)

1992 Fact Sheet, North Texas Institute for Educators on the Visual Arts

Photocopy of a document that lists out the districts served by NTIEVA and breaks down the institutions, teachers, and students served. The document also lists the members involved in the project and the goals that they have for the program.
Date: 1992
Creator: North Texas Institute for Educators on the Visual Arts
System: The UNT Digital Library
Accelerator research studies (open access)

Accelerator research studies

The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.
Date: January 1, 1992
Creator: unknown
System: The UNT Digital Library
The ACPMAPS system: A detailed overview (open access)

The ACPMAPS system: A detailed overview

This paper describes the ACPMAPS computing system -- its purpose, its hardware architecture, how the system is used, and relevant programming paradigms and concepts. Features of the hardware and software will be discussed in some detail, both quantitative and qualitative. This should give some perspective as to the suitability of the ACPMAPS system for various classes of applications, and as to where this system stands in the spectrum of today's supercomputers. The ACPMAPS project at Fermilab was initiated in 1987 as a collaborations between the Advanced Computer Program (now the Computer R D department) and the lattice gauge physicists in the Theory department. ACPMAPS is an acronym for Advanced Computer Program Multiple Array Processor System -- this acronym is no longer accurate, but the name has stuck. Although research physics computations were done on ACPMAPS as early as 1989, the full-scale system was commissioned as a reliable physics tool in early 1991. The original ACPMAPS was a 5 Gflop (peak) system. An upgrade by a factor of ten in computer power and memory size, but substituting a new CPU board, will occur during early 1991 -- this is referred to as the new ACPMAPS Upgrade or 50 GF ACPMAPS. The …
Date: January 1, 1992
Creator: Fischler, M.
System: The UNT Digital Library
ADIFOR Exception Handling (open access)

ADIFOR Exception Handling

Automatic differentiation uses recurrence relations based on the rules of calculus. Consequently, the results are guaranteed to be correct only in the relevant mathematical assumptions are satisfied at least in a neighborhood of the current argument. Computer programs may violate these conditions by branching or by calling intrinsic functions such as abs, max, sqrt, and asin at point where their derivative is undefined or infinite. The resulting dependence between the program's input and output variables may still be differentiable, because branch vales fit together smoothly or nondifferentiabilities cancel each other out. We have two objectives. First, we would like to assure the user that the function being evaluated is indeed locally differentiable because all intrinsics are evaluated at smooth arguments and none of the branching tests are critical. Second, the derivative program should run even when the assumptions of the chain rule are not strictly satisfied. In this case, the numerical results represent at least generalized derivations under reasonable (but usually unverifiable) regularity assumptions. To achieve these two goals, we must take into account the effects of finite-precision arithmetic. This paper addresses the detection and handling of exceptions. It is an exception in the ADIFOR-generated code to evaluate a function …
Date: January 1, 1992
Creator: Bischof, C.; Corliss, G. & Griewank, A.
System: The UNT Digital Library
ADIFOR Exception Handling. ADIFOR Working Note No. 3 (open access)

ADIFOR Exception Handling. ADIFOR Working Note No. 3

Automatic differentiation uses recurrence relations based on the rules of calculus. Consequently, the results are guaranteed to be correct only in the relevant mathematical assumptions are satisfied at least in a neighborhood of the current argument. Computer programs may violate these conditions by branching or by calling intrinsic functions such as abs, max, sqrt, and asin at point where their derivative is undefined or infinite. The resulting dependence between the program`s input and output variables may still be differentiable, because branch vales fit together smoothly or nondifferentiabilities cancel each other out. We have two objectives. First, we would like to assure the user that the function being evaluated is indeed locally differentiable because all intrinsics are evaluated at smooth arguments and none of the branching tests are critical. Second, the derivative program should run even when the assumptions of the chain rule are not strictly satisfied. In this case, the numerical results represent at least generalized derivations under reasonable (but usually unverifiable) regularity assumptions. To achieve these two goals, we must take into account the effects of finite-precision arithmetic. This paper addresses the detection and handling of exceptions. It is an exception in the ADIFOR-generated code to evaluate a function …
Date: January 1, 1992
Creator: Bischof, C.; Corliss, G. & Griewank, A.
System: The UNT Digital Library
ADIFOR Working Note #2: Using ADIFOR to Compute Dense and Sparse Jacobians (open access)

ADIFOR Working Note #2: Using ADIFOR to Compute Dense and Sparse Jacobians

ADIFOR is a source translator that, given a collection of Fortran subroutines for the computation of a ``function,`` produces Fortran code for the computation of the derivatives of this function. More specifically, ADIFOR produces code to compute the matrix-matrix product JS, where J is the Jacobian of the ``function`` with respect to the user-defined independent variables, and S is the composition of the derivative objects corresponding to the independent variables. This interface is flexible; by setting S = x, one can compute the matrix-vector product Jx, or by setting S = I, one can compute the whole Jacobian J. Other initializations of S allow one to exploit a known sparsity structure of J. This paper illustrates the proper initialization of ADIFOR-generated derivative codes and the exploitation of a known structure of J.
Date: January 1, 1992
Creator: Bischof, C. & Hovland, P.
System: The UNT Digital Library
Adsorption of aniline and toluidines on montmorillonite: Implications for the disposal of shale oil production wastes (open access)

Adsorption of aniline and toluidines on montmorillonite: Implications for the disposal of shale oil production wastes

Bentonite clay liners are commonly employed to mitigate the movement of contaminants from waste disposal sites. Solid and liquid waste materials that arise from the production of shale oil contain a vast array of organic compounds. Common among these compounds are the aromatic amines. in order to assess the ability of clay liner material to restrict organic compound mobility, the adsorption of aniline and o-, m-, and p-toluidine on Ca{sup 2+} - and K{sup +}-saturated Wyoming bentonite was investigated. Adsorption experiments were performed under conditions of varied pH, ionic strength, and dominate electrolyte cation and anion. organic adsorption on Ca{sup 2+} - and K{sup +}-saturated montmorillonite is pH dependent. For any given organic compound, maximum adsorption increases with decreasing ionic strength. organic compound adsorption is inhibited in the presence of sulfate and is greater in the Ca{sup 2+} systems than in the K{sup +} systems at any given ionic strength. High salt content and K{sup +} collapse the bentonite layers and limit access to and compete for adsorption sites. The K{sup +} ion is also more difficult to displace than Ca{sup 2+} from interlayer positions. Fourier transform infrared spectroscopic data show that the aniline compounds are adsorbed on bentonite through …
Date: January 1, 1992
Creator: Essington, M. E.; Bowen, J. M.; Wills, R. A. & Hart, B. K.
System: The UNT Digital Library
Adsorption of aniline and toluidines on montmorillonite: Implications for the disposal of shale oil production wastes (open access)

Adsorption of aniline and toluidines on montmorillonite: Implications for the disposal of shale oil production wastes

Bentonite clay liners are commonly employed to mitigate the movement of contaminants from waste disposal sites. Solid and liquid waste materials that arise from the production of shale oil contain a vast array of organic compounds. Common among these compounds are the aromatic amines. in order to assess the ability of clay liner material to restrict organic compound mobility, the adsorption of aniline and o-, m-, and p-toluidine on Ca[sup 2+] - and K[sup +]-saturated Wyoming bentonite was investigated. Adsorption experiments were performed under conditions of varied pH, ionic strength, and dominate electrolyte cation and anion. organic adsorption on Ca[sup 2+] - and K[sup +]-saturated montmorillonite is pH dependent. For any given organic compound, maximum adsorption increases with decreasing ionic strength. organic compound adsorption is inhibited in the presence of sulfate and is greater in the Ca[sup 2+] systems than in the K[sup +] systems at any given ionic strength. High salt content and K[sup +] collapse the bentonite layers and limit access to and compete for adsorption sites. The K[sup +] ion is also more difficult to displace than Ca[sup 2+] from interlayer positions. Fourier transform infrared spectroscopic data show that the aniline compounds are adsorbed on bentonite through …
Date: January 1992
Creator: Essington, M. E.; Bowen, J. M.; Wills, R. A. & Hart, B. K.
System: The UNT Digital Library
Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama (open access)

Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama

This report presents the results of Run 260 performed at the Advanced Coal Liquefaction R D Facility in Wilsonville. The run was started on July 17, 1990 and continued until November 14, 1990, operating in the Close-Coupled Integrated Two-Stage Liquefaction mode processing Black Thunder mine subbituminous coal (Wyodak-Anderson seam from Wyoming Powder River Basin). Both thermal/catalytic and catalytic/thermal tests were performed to determine the methods for reducing solids buildup in a subbituminous coal operation, and to improve product yields. A new, smaller interstage separator was tested to reduce solids buildup by increasing the slurry space velocity in the separator. In order to obtain improved coal and resid conversions (compared to Run 258) full-volume thermal reactor and 3/4-volume catalytic reactor were used. Shell 324 catalyst, 1/16 in. cylindrical extrudate, at a replacement rate of 3 lb/ton of MF coal was used in the catalytic stage. Iron oxide was used as slurry catalyst at a rate of 2 wt % MF coal throughout the run. (TNPS was the sulfiding agent.)
Date: January 1, 1992
Creator: unknown
System: The UNT Digital Library
Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama. Run 260 with Black Thunder Mine subbituminous coal: Technical progress report (open access)

Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama. Run 260 with Black Thunder Mine subbituminous coal: Technical progress report

This report presents the results of Run 260 performed at the Advanced Coal Liquefaction R&D Facility in Wilsonville. The run was started on July 17, 1990 and continued until November 14, 1990, operating in the Close-Coupled Integrated Two-Stage Liquefaction mode processing Black Thunder mine subbituminous coal (Wyodak-Anderson seam from Wyoming Powder River Basin). Both thermal/catalytic and catalytic/thermal tests were performed to determine the methods for reducing solids buildup in a subbituminous coal operation, and to improve product yields. A new, smaller interstage separator was tested to reduce solids buildup by increasing the slurry space velocity in the separator. In order to obtain improved coal and resid conversions (compared to Run 258) full-volume thermal reactor and 3/4-volume catalytic reactor were used. Shell 324 catalyst, 1/16 in. cylindrical extrudate, at a replacement rate of 3 lb/ton of MF coal was used in the catalytic stage. Iron oxide was used as slurry catalyst at a rate of 2 wt % MF coal throughout the run. (TNPS was the sulfiding agent.)
Date: January 1, 1992
Creator: unknown
System: The UNT Digital Library
Advanced direct coal liquefaction concepts (open access)

Advanced direct coal liquefaction concepts

During the first quarter of FY 1993, the Project proceeded close to the Project Plan. The analysis of the feed material has been completed as far as possible. Some unplanned distillation was needed to correct the boiling range of the Black Thunder solvent used during the autoclave tests. Additional distillation will be required if the same solvent is to be used for the bench unit tests. A decision on this is still outstanding. The solvent to be used with Illinois No. 6 coal has not yet been defined. As a result, the procurement of the feed and the feed analysis is somewhat behind schedule. Agglomeration tests with Black Thunder coal indicates that small agglomerates can be formed. However, the ash removal is quite low (about 10%), which is not surprising in view of the low ash content of the coal. The first series of autoclave tests with Black Thunder coal was completed as planned. Also, additional runs are in progress as repeats of previous runs or at different operating conditions based on the data obtained so far. The results are promising indicating that almost complete solubilization (close to 90%) of Black Thunder coal can be achieved in a CO/H[sub 2]O …
Date: January 1, 1992
Creator: Berger, D. J.; Parker, R. J. & Simpson, P. L.
System: The UNT Digital Library
Advanced Neutron Source (ANS) Project Progress report, FY 1991 (open access)

Advanced Neutron Source (ANS) Project Progress report, FY 1991

This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I & C Research and Development; Design; and Safety.
Date: January 1, 1992
Creator: Campbell, J. H.; Selby, D. L.; Harrington, R. M. & Thompson, P. B.
System: The UNT Digital Library
Advanced Neutron Source (ANS) Project Progress report, FY 1991 (open access)

Advanced Neutron Source (ANS) Project Progress report, FY 1991

This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I C Research and Development; Design; and Safety.
Date: January 1, 1992
Creator: Campbell, J. H. (ed.) (Oak Ridge National Lab., TN (United States)); Selby, D. L.; Harrington, R. M. (Oak Ridge National Lab., TN (United States)) & Thompson, P. B. (Martin Marietta Energy Systems, Inc., (United States). Engineering Division)
System: The UNT Digital Library
Advanced NMR Approaches in the Characterization of Coal (open access)

Advanced NMR Approaches in the Characterization of Coal

A considerable effort in this project during the past few months has been focussed on the development of [sup 1]H and [sup 13]C NMR imaging techniques to yield spatially-resolved chemical shift (structure) information on coal. In order to yield the chemical shift information, a solid-state NMR imaging technique must include magic-angle spinning, so rotating gradient capabilities are indicated. A [sup 13]C MAS imaging probe and a [sup 1]H MAS imaging probe and the circuitry necessary for rotating gradients have been designed and constructed. The [sup 1]H system has already produced promising preliminary results, which are briefly described in this report.
Date: January 1, 1992
Creator: Maciel, G. E.
System: The UNT Digital Library
Advanced Nmr Approaches in the Characterization of Coal (open access)

Advanced Nmr Approaches in the Characterization of Coal

The paper submitted earlier on the use of (bicyclo[3.2.1]4pyrrolidino-N-methyl-octan-8-one triflate) ([sup 13]CO-123) as a [sup 13]C intensity standard was accepted for publication. Subsequently, [sup 13]CO-321 was used in this manner for quantitative [sup 13]C CP-MAS NMR analysis (including spin counting) of Argonne Premium coals. The cross-polarization time constants, T[sub CH], and the rotating-frame proton spin-lattice relaxation times, T[sub 1p][sup H], were determined for each major peak of each coal via a combination of variable contact-time and variable spin-lock (T[sub 1p][sup H]) experiments. Two or three components of rotating-frame [sup 1]H relaxation decay and two or three components of T[sub CH] behavior were observed for each major [sup 13]C peak of each coal. These data were used to determine the number of carbon atoms detected in each coal; these values are in the range between 77% and 87% of the amount of carbon known to be in each coal from elemental analysis data, except for Pocahontas No. 3, for which only 50% of the carbon was detected. In an attempt to use [sup 1]H CRAMPS to elucidate chemical functionality in coal, pyridine-saturated samples of the Argonne Premium coals were examined in detail in terms of their [sup 1]H CRAMPS NMR spectra. …
Date: January 1, 1992
Creator: Maciel, G. E.
System: The UNT Digital Library
Advanced NMR-based techniques for pore structure analysis of coal (open access)

Advanced NMR-based techniques for pore structure analysis of coal

One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We will investigate the dependence of the common NMR parameters such as chemical shifts and relaxation times of several different nuclei and compounds on the pore structure of model microporous solids, carbons, and coals. In particular, we will study the interaction between several small molecules ({sup 129}Xe, {sup 3}He, {sup 2}H{sub 2}, {sup 14}N{sub 2}, {sup 14}NH{sub 3}, {sup 15}N{sub 2}, {sup 13}CH{sub 4}, {sup 13}CO{sub 2}) and the pore surfaces in coals. These molecules have been selected for their chemical and physical properties. A special NMR probe will be constructed which will allow the concurrent measurement of NMR properties and adsorption uptake at a variety of temperatures. All samples will be subjected to a suite of conventional'' pore structure analyses. These include nitrogen adsorption at 77 K with BET analysis, C0{sub 2} and CH{sub 4} adsorption at 273 K with D-R (Dubinin-Radushkevich) analysis, helium …
Date: January 1, 1992
Creator: Smith, D. M.
System: The UNT Digital Library
Advanced NMR-based techniques for pore structure analysis of coal (open access)

Advanced NMR-based techniques for pore structure analysis of coal

One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. Conventional pore size techniques (adsorption/condensation, mercury porosimetry) are limited because of this broad pore size range, microporosity, reactive nature of coal, samples must be completely dried, and network/percolation effects. Small angle scattering is limited because it probes both open and closed pores. Although one would not expect any single technique to provide a satisfactory description of a coal's structure, it is apparent that better techniques are necessary. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We will investigate the dependence of the common NMR parameters such as chemical shifts and relaxation times of several different nuclei and compounds on the pore structure of model microporous solids, carbons, and coals. In particular, we will study the interaction between several small molecules and the pore surfaces in coals. These molecules have been selected for their chemical and physical properties. A special NMR probe will be constructed which will allow the concurrent measurement of NMR properties …
Date: January 1, 1992
Creator: Smith, Douglas M.
System: The UNT Digital Library
Advanced NMR-based techniques for pore structure analysis of coal (open access)

Advanced NMR-based techniques for pore structure analysis of coal

One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. Conventional pore size techniques (adsorption/condensation, mercury porosimetry) are limited because of this broad pore size range, microporosity, reactive nature of coal, samples must be completely dried, and network/percolation effects. Small angle scattering is limited because it probes both open and closed pores. Although one would not expect any single technique to provide a satisfactory description of a coal's structure, it is apparent that better techniques are necessary. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We now have two suites of well-characterized microporous materials including oxides (zeolites and silica gel) and activated carbons from our industrial partner, Air Products in Allentown, PA. Our current work may be divided into three areas: small-angle X-ray scattering (SAXS), adsorption, and NMR.
Date: January 1, 1992
Creator: Smith, Douglas M.
System: The UNT Digital Library
Advanced Scientific Computing Environment Team (open access)

Advanced Scientific Computing Environment Team

The mission of the ASCENT (Advanced Scientific Computing EnvironmenT) Team is continually keep pace with, evaluate, and select emerging computing technologies to define and implement prototypic scientific computing environments that maximize the ability of scientists and engineers to manage scientific data. These environments are to be implemented in a manner consistent with the site computing architecture and standards and strategic plans for scientific computing. A broad, long term, goal of the ASCENT Team is to provide a computing environment that will let scientists and engineers function at the higher level of abstraction that is their actual area of technical expertise. The scientist/engineer should be able to solve problems by interacting with conceptual representations drawn directly from the scientific and engineering domains. In this environment the scientist/engineer (i.e., the problem solver'') builds the problem model with reusable virtual objects having associated attributes and behaviors, including any real or artificial constraints. The problem solver could then test the model by perturbing it interactively and observing quantitative (archived experimental measurements; simulated or computed data) and/or qualitative (trends, approximations) responses. Such an environment would greatly aid the solution and understanding of scientific and engineering problems. This report discusses the proposed system, program, graphic tools …
Date: January 1, 1992
Creator: Church, J.P.
System: The UNT Digital Library