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Multiplicity moments in e{sup +}e{sup {minus}} annihilation into hadrons at the Z{sup 0} resonance

Description: The authors present the ratio of cumulant to factorial moments of multiplicity distributions in hadronic events from Z{sup 0} decays. Their preliminary result show that this ratio, as a function of moment rank q, decreases sharply to a negative minimum at q {approximately} 5, followed by a sequence of quasi-oscillations. These observed features are in qualitative agreement with expectations from higher-order perturbative QCD.
Date: August 1, 1994
Creator: Zhou, J.
Partner: UNT Libraries Government Documents Department

Biomolecular Origin of The Rate-Dependent Deformation of Prismatic Enamel

Description: Penetration deformation of columnar prismatic enamel was investigated using instrumented nanoindentation testing, carried out at three constant strain rates (0.05 s{sup -1}, 0.005 s{sup -1}, and 0.0005 s{sup -1}). Enamel demonstrated better resistance to penetration deformation and greater elastic modulus values were measured at higher strain rates. The origin of the rate-dependent deformation was rationalized to be the shear deformation of nanoscale protein matrix surrounding each hydroxyapatite crystal rods. And the shear modulus of protein matrix was shown to depend on strain rate in a format: G{sub p} = 0.213 + 0.021 ln {dot {var_epsilon}}. Most biological composites compromise reinforcement mineral components and an organic matrix. They are generally partitioned into multi-level to form hierarchical structures that have supreme resistance to crack growth [1]. The molecular mechanistic origin of toughness is associated with the 'sacrificial chains' between the individual sub-domains in a protein molecule [2]. As the protein molecule is stretched, these 'sacrificial chains' break to protect its backbone and dissipate energy [3]. Such fresh insights are providing new momentum toward updating our understanding of biological materials [4]. Prismatic enamel in teeth is one such material. Prismatic microstructure is frequently observed in the surface layers of many biological materials, as exemplified in mollusk shells [5] and teeth [6]. It is a naturally optimized microstructure to bear impact loading and penetration deformation. In teeth, the columnar prismatic enamel provides mechanical and chemical protection for the relatively soft dentin layer. Its mechanical behavior and reliability are extremely important to ensure normal tooth function and human health. Since enamel generally contains up to 95% hydroxyapatite (HAP) crystals and less than 5% protein matrix, it is commonly believed to be a weak and brittle material with little resistance to fracture [7]. This study is aimed at exploring the effect of the weak amelogenin-rich protein ...
Date: July 5, 2006
Creator: Zhou, J & Hsiung, L
Partner: UNT Libraries Government Documents Department

Depth Dependence of the Mechanical Properties of Human Enamel by Nanoindentation

Description: Nanoindentation has recently emerged to be the primary method to study the mechanical behavior and reliability of human enamel. Its hardness and elastic modulus were generally reported as average values with standard deviations that were calculated from the results of multiple nanoindentation tests. In such an approach, it is assumed that the mechanical properties of human enamel are constant, independent of testing parameters, like indent depth and loading rate. However, little is known if they affect the measurements. In this study, we investigated the dependence of the hardness and elastic modulus of human enamel on the indent depth. We found that in a depth range from 100 nm to 2000 nm the elastic moduli continuously decreased from {approx} 104 GPa to {approx} 70 GPa, and the hardnesses decreased from {approx} 5.7 GPa to {approx} 3.6 GPa. We then considered human enamel as a fiber-reinforced composite, and used the celebrated rule of mixture theory to quantify the upper and lower bounds of the elastic moduli, which were shown to cover the values measured in the current study and previous studies. Accordingly, we attributed the depth dependence of the hardness and modulus to the continuous microstructure evolution induced by nanoindenter.
Date: February 17, 2006
Creator: Zhou, J & Hsiung, L L
Partner: UNT Libraries Government Documents Department

Microstructure and Mechanical Instability of Water-Quenched U-6wt% Nb Alloy Affected by Long-Term Aging

Description: A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis was employed to study the microstructure and mechanical instability of a water-quenched U-6wt.% Nb (WQ-U6Nb) alloy subjected to different aging schedules including artificial aging at 200 C, 15-year natural aging at ambient temperatures, and 15-year natural aging followed by accelerative aging at 200 C. The changes in mechanical property during and after the aging processes were examined using microhardness and tensile-testing methods. During the early stages of artificial aging at 200 C, the microhardness of WQ-U6Nb alloy increased, i.e., age hardening, as a result of the development of nanoscale modulation caused by spinodal decomposition. Coarsening of the modulated structure occurred after a prolonged aging at 200 C for 16 hours, and it led to a decrease of microhardness, i.e., age softening. Phase instability was also found to occur in WQ-U6Nb alloy that was subjected to a 15-year natural aging at ambient temperatures. The formation of partially ordered domains resulting from a spinodal modulation with an atomic-scale wavelength rendered the appearance of swirl-shape antiphase domain boundaries (APBs) observed in TEM images. Although it did not cause a significant change in microhardness, 15-year natural aging has dramatically affected the aging mechanisms of the alloy isothermally aged at 200 C. Microhardness values of the NA alloy continuously increased and no age softening was found after isothermal aging at 200 C for 96 hours as a result of the phase decomposition of partially ordered domains into Nb-depleted {alpha} phase and Nb-enriched U{sub 3}Nb ordered phase in the alloy. It is concluded that the long-term natural aging changes the transformation pathway of WQ-U6Nb, and it leads to order-disorder transformation, precipitation hardening, and ductility embrittlement of WQ-U6Nb alloy.
Date: December 6, 2005
Creator: Hsiung, L & Zhou, J
Partner: UNT Libraries Government Documents Department

Transverse momentum dependent quark distributions and polarized Drell-Yan processes

Description: We study the spin-dependent quark distributions at large transverse momentum. We derive their transverse momentum behaviors in the collinear factorization approach in this region. We further calculate the angular distribution of the Drell-Yan lepton pair production with polarized beams and present the results in terms of the collinear twist-three quark-gluon correlation functions. In the intermediate transverse momentum region, we find that the two pproaches: the collinear factorization and the transverse momentum dependent factorization approaches are consistent in the description of the lepton pair angular distributions.
Date: September 11, 2009
Creator: Zhou, J.; Yuan, F. & Liang, Z.-T.
Partner: UNT Libraries Government Documents Department

Spinodal Decomposition and Order-Disorder Transformation in a Water-Quenched U-6wt%Nb Alloy

Description: A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis has been employed to study phase stability and aging mechanisms of a water-quenched U-6wt%Nb (WQU6Nb) alloy subjected to different aging schedules that include artificial aging of WQ-U6Nb at 200 C, natural aging of WQ-U6Nb at ambient temperatures for 15 to18 years, and accelerative aging of the naturally aged (NA) alloy at 200 C. During the early stages of artificial aging at 200 C, the microhardness values continuously increase as a result of the development of a fine-scale compositional modulation (wavelength: 3 nm) caused by spinodal decomposition. Coarsening of the modulated structure occurs after prolonged aging of WQ-U6Nb at 200 C for 16 hours, which leads to a decrease of microhardness. Phase instability has also been found to occur in the NA alloy, in which the formation of partially ordered phase domains resulting from an atomic-scale spinodal modulation (wavelength: 0.5 nm) renders the appearance of antiphase domain boundaries (APBs) in TEM images. Although 18-year natural aging does not cause a significant change in hardness, it affects dramatically the aging mechanism of WQ-U6Nb subjected to the accelerative aging at 200 C. The result of microhardness measurement shows that the hardness values continuously increase until after aging for 239 hours, and the total hardness increment is twice in magnitude than that in the case of the artificial aging of water-quenched alloy at 200 C. The anomalous increment of hardness for the accelerative aging of NA alloy can be attributed to the precipitation of an ordered U{sub 3}Nb phase. It is accordingly concluded that the long-term natural aging at ambient temperatures can detour the transformation pathway of WQ U-6Nb alloy; it leads to the order-disorder transformation and precipitation of ordered phase in the alloy.
Date: September 12, 2006
Creator: Hsiung, L & Zhou, J
Partner: UNT Libraries Government Documents Department

Spinodal Ordering and Precipitation in U-6 wt% Nb

Description: A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis was employed to study the microstructure and mechanical instability of a water-quenched U-6wt.% Nb (WQU6Nb) alloy subjected to different aging schedules including artificial aging at 200 C, 15-year natural aging at ambient temperatures, and 15-year natural aging followed by accelerative aging at 200 C. The changes in mechanical property during and after the aging processes were examined using microhardness and tensile-testing methods. During the early stages of artificial aging at 200 C, the microhardness of WQ-U6Nb alloy increased, i.e., age hardening, as a result of the development of nanoscale modulation caused by spinodal decomposition. Coarsening of the modulated structure occurred after a prolonged aging at 200 C for 16 hours, and it led to a decrease of microhardness, i.e., age softening. Phase instability was also found to occur in WQ-U6Nb alloy that was subjected to a 15-year natural aging at ambient temperatures. The formation of partially ordered domains resulting from a spinodal modulation with an atomic-scale wavelength rendered the appearance of swirl-shape antiphase domain boundaries (APBs) observed in TEM images. Although it did not cause a significant change in microhardness, 15-year natural aging has dramatically affected the aging mechanisms of the alloy isothermally aged at 200 C. Microhardness values of the NA alloy continuously increased after isothermal aging at 200 C for 96 hours as a result of the phase decomposition of partially ordered domains into Nb-depleted {alpha} phase and Nb-enriched U{sub 3}Nb ordered phase in the alloy. It is concluded that the long-term natural aging changes the transformation pathway of WQ-U6Nb, and it leads to order-disorder transformation and precipitation hardening of WQ-U6Nb alloy.
Date: December 19, 2005
Creator: Hsiung, L & Zhou, J
Partner: UNT Libraries Government Documents Department

Long-Term Phase Instability in A Water-Quenched Uranium Alloy

Description: The U-6 wt.% Nb (U6Nb) alloy in water-quenched (WQ) state has been in service for a number of years. Its long-term reliability is affected by the changes of the alloy microstructure and mechanical properties during service. In this communication, the water quenched U-6 wt.% Nb (WQ-U6Nb) alloy in service for 15 years at ambient temperatures was studied using an analytical TEM analysis. We found that the long-term natural aging resulted in a disorder-order phase transformation, leading to the formation of anti-phase boundaries (APBs). The newly-found ordered phase was then identified by proposing two phase transform schemes, which were also discussed with regards to the potential subsequence of the microstructural evolution for the alloy in further service. The initial study also provides convincing evidence for the disorder-order transformation, which has been predicted by numerous studies to be a transient thermodynamic event before spinodal decomposition. This suggests that the long-term naturally aged WQ-U6Nb is a good model alloy to study thermodynamic and kinetic phenomena requiring chronic processes.
Date: August 11, 2005
Creator: Hsiung, L L & Zhou, J
Partner: UNT Libraries Government Documents Department

Long-Term Phase Instability in Water-Quenched U-6Nb

Description: A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis was employed to study the microstructure and mechanical instability of a water-quenched U-6wt.% Nb (WQ-U6Nb) alloy subjected to different aging schedules including artificial aging at 200 C, 15-year natural aging at ambient temperatures, and 15-year natural aging followed by accelerative aging at 200 C. The changes in mechanical property during and after the aging processes were examined using microhardness and tensile-testing methods. During the early stages of artificial aging at 200 C, the microhardness of WQ-U6Nb alloy increased, i.e., age hardening, as a result of the development of nanoscale modulation caused by spinodal decomposition. Coarsening of the modulated structure occurred after a prolonged aging at 200 C for 16 hours, and it led to a decrease of microhardness, i.e., age softening. Phase instability was also found to occur in WQ-U6Nb alloy that was subjected to a 15-year natural aging at ambient temperatures. The formation of partially ordered domains resulting from a spinodal modulation with an atomic-scale wavelength rendered the appearance of swirl-shape antiphase domain boundaries (APBs) observed in TEM images. Although it did not cause a significant change in microhardness, 15-year natural aging has dramatically affected the aging mechanisms of the alloy isothermally aged at 200 C. Microhardness values of the NA alloy continuously increased after isothermal aging at 200 C for 96 hours as a result of the phase decomposition of partially ordered domains into Nb-depleted {alpha} phase and Nb-enriched U{sub 3}Nb ordered phase in the alloy. It is concluded that the long-term natural aging changes the transformation sequence of WQ-U6Nb, and it leads to order-disorder transformation, precipitation hardening, and ductility embrittlement of WQ-U6Nb alloy.
Date: January 16, 2006
Creator: Hsiung, L L & Zhou, J
Partner: UNT Libraries Government Documents Department

Low-Temperature Aging Kinetics of a 15-Year Old Water-Quenched U-6wt.% Nb Alloy

Description: It is well known that U-6wt.% Nb (U-14at.% Nb) alloy has a microstructure containing martensitic phases supersaturated with Nb that can be obtained by rapid quenching the alloy from {gamma} (bcc)-field solid solution to room temperature. The high cooling rate forces the {gamma}-phase solid solution to transform to variants of the low-temperature {alpha} (orthorhombic) phase in which Nb is forced to retain in the supersaturated solid solution. However, the crystal lattice of supersaturated solution formed by rapid quenching is in unstable conditions and is severely distorted since the solubility of Nb in the {alpha} phase at room temperature is nearly zero under an equilibrium condition. Two variant phases, a monoclinic distortion of {alpha} phase that is designated as {alpha}{double_prime} martensite and a tetragonal distortion of {gamma} phase that is designated as {gamma}{sup o} phase, can form in the as-quenched alloy, as shown in Fig. 1. We have learned from our previous TEM studies on the low-temperature aging of a water-quenched U6Nb (WQ-U6Nb) alloy that there are two possible transformation pathways for phase decomposition of the alloy supersaturated with 14 at.% of Nb upon aging at temperatures below 200 C, i.e., (1) supersaturated solid solution {alpha}{double_prime} {yields} spinodal decomposition {yields} {alpha}{sub 1} (Nb-lean) + {alpha}{sub 2} (Nb-rich) at 200 C and (2) supersaturated solid solution {alpha}{double_prime} {yields} spinodal ordering {yields}{alpha}{double_prime}{sub po} (partially ordered phase) {yields} phase decomposition and precipitation {yields} {alpha} (U) + {alpha}{sub o} (U{sub 3}Nb) at ambient temperatures [1]. The mechanisms for the spinodal transformation occurred at 200 C and the spinodal ordering occurred at ambient temperatures are quite similar; both are caused by the composition modulation of Nb except that the wavelength ({lambda} {approx} 3 nm) of modulation for spinodal decomposition is larger than that ({lambda} {approx} 0.5 nm) of modulation for the spinodal ordering, as illustrated in ...
Date: October 30, 2007
Creator: Hsiung, L & Zhou, J
Partner: UNT Libraries Government Documents Department

Siting Evaluation for Biomass-Ethanol Production in Hawaii

Description: This report examines four Hawaiian islands, Oahu, Hawaii, Maui, and Kauai, to identify three best combinations of potential sites and crops for producing dedicated supplies of biomass for conversion to ethanol. Key technical and economic factors considered in the siting evaluation include land availability (zoning and use), land suitability (agronomic conditions), potential quantities and costs of producing biomass feedstocks, infrastructure (including water and power supplies), transportation, and potential bioresidues to supplement dedicated energy crops.
Date: October 15, 2000
Creator: Kinoshita, C.M. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Slang characterization and removal using pulse detonation technology during coal gasification

Description: Boiler slagging and fouling as a result of inorganic impurities in combustion gases being deposited on heat transfer tubes have caused severe problems in coal-fired power plant operation. These problems are fuel, system design, and operating condition dependent. Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. The detonation wave technique based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. These detonation waves have been demonstrated experimentally to have exceptionally high shearing capability important to the task of removing slag and fouling deposits. The experimental results show that the single shot detonation wave is capable of removing the entire slag (types of slag deposited on economizer) even at a distance of 8 in. from the exit of a detonation engine tube. Wave strength and slag orientation also have different effects on the chipping off of the slag. This paper discusses about the results obtained in effectively removing the economizer slag.
Date: March 25, 1997
Creator: Huque, Z.; Mei, D.; Biney, P.O. & Zhou, J.
Partner: UNT Libraries Government Documents Department

An X-ray Study of Shock-Recovered Tantalum Single Crystals

Description: In this paper, we report shock-induced new grains and residual lattice tension in tantalum single crystals. The single crystals with orientations in [001], [011], [111], and [123] directions are shocked at {approx}55 GPa in gas gun under almost identical conditions. New grains in the shocked crystals are revealed by x-ray scanning analysis. Rather than lattice compression that is frequently probed by in situ x-ray diffraction technique, we find significant residual lattice tension in the recovered tantalum crystals. Such residual lattice tension is attributed to the dislocation cells and their deformation. The dislocation cells are accordingly estimated to be greater than 100 nm from broadening of x-ray diffraction peak.
Date: August 2, 2007
Creator: Zhou, J; Hsiung, L L; Chau, R & Saw, C K
Partner: UNT Libraries Government Documents Department

Substrate Creep on The Fatigue Life of A Model Dental Multilayer Structure

Description: In this paper, we investigated the effects of substrate creep on the fatigue behavior of a model dental multilayer structure, in which a top glass layer was bonded to a polycarbonate substrate through a dental adhesive. The top glass layers were ground using 120 grit or 600 grit sand papers before bonding to create different sub-surface crack sizes and morphologies. The multilayer structures were tested under cyclic Hertzian contact loading to study crack growth and obtain fatigue life curves. The experiment results showed that the fatigue lives of the multilayer structures were impaired by increasing crack sizes in the sub-surfaces. They were also significantly reduced by the substrate creep when tested at relatively low load levels i.e. P{sub m} < 60 N (Pm is the maximum magnitude of cyclic load). But at relatively high load levels i.e. P{sub m} > 65 N, slow crack growth (SCG) was the major failure mechanisms. A modeling study was then carried out to explore the possible failure mechanisms over a range of load levels. It is found that fatigue life at relatively low load levels can be better estimated by considering the substrate creep effect (SCE).
Date: October 9, 2006
Creator: Zhou, J; Huang, M; Niu, X & soboyejo, W
Partner: UNT Libraries Government Documents Department

Final Report Construction of Whole Genome Microarrays, and Expression Analysis of Desulfovibrio vulgaris cells in Metal-Reducing Conditions

Description: We continue to utilize the oligonucleotide microarrays that were constructed through funding with this project to characterize growth responses of Desulfovibrio vulgaris relevant to metal-reducing conditions. To effectively immobilize heavy metals and radionuclides via sulfate-reduction, it is important to understand the cellular responses to adverse factors observed at contaminated subsurface environments (e.g., nutrients, pH, contaminants, growth requirements and products). One of the major goals of the project is to construct whole-genome microarrays for Desulfovibrio vulgaris. First, in order to experimentally establish the criteria for designing gene-specific oligonucleotide probes, an oligonucleotide array was constructed that contained perfect match (PM) and mismatch (MM) probes (50mers and 70mers) based upon 4 genes. The effects of probe-target identity, continuous stretch, mismatch position, and hybridization free energy on specificity were examined. Little hybridization was observed at a probe-target identity of <85% for both 50mer and 70mer probes. 33 to 48% of the PM signal intensities were detected at a probe-target identity of 94% for 50mer oligonucleotides, and 43 to 55% for 70mer probes at a probe-target identity of 96%. When the effects of sequence identity and continuous stretch were considered independently, a stretch probe (>15 bases) contributed an additional 9% of the PM signal intensity compared to a non-stretch probe (< 15 bases) at the same identity level. Cross-hybridization increased as the length of continuous stretch increased. A 35-base stretch for 50mer probes or a 50-base stretch for 70mer probes had approximately 55% of the PM signal. Mismatches should be as close to the middle position of an oligonucleotide probe as possible to minimize cross-hybridization. Little cross-hybridization was observed for probes with a minimal binding free energy greater than -30 kcal/mol for 50mer probes or -40 kcal/mol for 70mer probes. Based on the experimental results, a set of criteria were suggested for the design of ...
Date: May 15, 2008
Creator: Fields, M.W.; Wall, J.D.; Keasling, J. & Zhou, J.
Partner: UNT Libraries Government Documents Department

The use of microarrays in microbial ecology

Description: Microarrays have proven to be a useful and high-throughput method to provide targeted DNA sequence information for up to many thousands of specific genetic regions in a single test. A microarray consists of multiple DNA oligonucleotide probes that, under high stringency conditions, hybridize only to specific complementary nucleic acid sequences (targets). A fluorescent signal indicates the presence and, in many cases, the abundance of genetic regions of interest. In this chapter we will look at how microarrays are used in microbial ecology, especially with the recent increase in microbial community DNA sequence data. Of particular interest to microbial ecologists, phylogenetic microarrays are used for the analysis of phylotypes in a community and functional gene arrays are used for the analysis of functional genes, and, by inference, phylotypes in environmental samples. A phylogenetic microarray that has been developed by the Andersen laboratory, the PhyloChip, will be discussed as an example of a microarray that targets the known diversity within the 16S rRNA gene to determine microbial community composition. Using multiple, confirmatory probes to increase the confidence of detection and a mismatch probe for every perfect match probe to minimize the effect of cross-hybridization by non-target regions, the PhyloChip is able to simultaneously identify any of thousands of taxa present in an environmental sample. The PhyloChip is shown to reveal greater diversity within a community than rRNA gene sequencing due to the placement of the entire gene product on the microarray compared with the analysis of up to thousands of individual molecules by traditional sequencing methods. A functional gene array that has been developed by the Zhou laboratory, the GeoChip, will be discussed as an example of a microarray that dynamically identifies functional activities of multiple members within a community. The recent version of GeoChip contains more than 24,000 50mer oligonucleotide probes ...
Date: September 15, 2009
Creator: Andersen, G.L.; He, Z.; DeSantis, T.Z.; Brodie, E.L. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Initial Failure Analysis of Ceramic Filters

Description: Effective high temperature ceramic filters are indispensable in the advanced, coal based power systems (IGCC and PFBC). To meet the environmental particulate emission requirements and improve thermal efficiency, ceramic filters are utilized to cleanup the hot gas particulate to protect downstream heat exchanger and gas turbine components from fouling and corrosion. The mechanical integrity of ceramic filters and an efficient dust cake removal system are the key issues for hot gas cleanup systems. The filters must survive combined stresses due to mechanical, thermal, chemical and steam attack throughout normal operations (cold back pulse cleaning jets), unexpected excessive ash accumulation, and the start up and shut down conditions. To evaluate the design and performance of ceramic filters, different long term filter testing programs were conducted. To fulfill this purpose, two Advanced Particle Filter (APF) systems were complete at Tidd PFBC Demonstration Plant in Brilliant, Ohio in late 1990 as part of the Department of Energy`s (DOE) Clean Coal Technology Program. However, many filter failures 1649 were reported prior to its desired life time. In Tidd APF vessel, 28 filters failed one time, The objectives of this program were to provide an understanding of the factors pertinent to the failures of ceramic filters by characterizing filter properties and the dust cake removal mechanism, Researches were emphasized on understanding of changes of filter properties and back pulse cleaning mechanism to resolve the issues relating to filter permeability variations, ash bridging and micro-thermal cracks induced during cold back pulse cleaning. To perform failure analysis of ceramic filters, thermal numerical simulation, material laboratory analysis on filter materials and dust cake, and measurements on filter properties and back pulse intensity along filter axis within a bench scale filter chamber were conducted.
Date: December 31, 1996
Creator: Huque, Z.; Mei, D. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Characterization and failure analysis of ceramic filters utilized for emission control during coal gasification. Topical report, October 1, 1995--September 30, 1996

Description: Ceramic filters for pollutant emission control from coal gasification have been evaluated. The following were investigated: permeability, cleaning, back pulse pressure distribution measurement within candle filter without dust cake, and optimization on back pulse system design.
Date: December 31, 1998
Creator: Huque, Ziaul, Mei, D. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Characterization and failure analysis of ceramic filters utilized for emission control during coal gasification. Quarterly report, July 1--September 30, 1997

Description: The research activities performed at PV A and M University in the third quarter of 1997 are summarized within. PV A and MU had performed mechanical and back pulse testing to characterize the performance of the filter and is using the process of elimination to perform the failure analysis for filters. The mechanical testing performed on the filters are categorized as follows: the acceleration testing; the vibration testing; the air jet impulse testing; and the impact testing. The major work completed in the third quarter, 1997 for filter back pulse cleaning testing included the following items: (1) the completion of the test system; (2) the procurement of particulate sample; (3) the development of a data acquisition system; (4) the filtration pressure field monitoring with the use of micro-fast pressure sensor assembly; (5) the design of a back pulse system; (6) completed a back pulse cleaning test plan; and (7) started performing parametric testing on particulate removal. The bulk of this report consists of a user`s manual for the automatic testing on instrumentation interfacing.
Date: December 31, 1997
Creator: Huque, Z. & Mei, D.: Zhou, J.
Partner: UNT Libraries Government Documents Department

Characterization and optimization of sorbents utilized for emission control during gasification. Quarterly report, January 1--March 31, 1997

Description: The report gives a summary of research activities and accomplishments during the current quarter. One of these is an automatic data acquisition system for automatic measurement of electrical signals and pressure sensor outputs. The bulk of this report is the user`s manual for this automatic test system. It describes the installation, programming, and operation of the test system.
Date: December 31, 1997
Creator: Huque, Z.; Mei, D. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Characterization and failure analysis of ceramic filters utilized for emission control during coal gasification. Quarterly report, July 1--September 30, 1996

Description: The research activities performed during the report period include: evaluation of filter samples as well as different type of filters; providing test data as a data base to verify gas stream flow numerical simulation of a filter test chamber; and characterization of the physical properties of ceramic candle filter gas flow properties in the newly completed test facility. The test facility sub-assemblies are described and test data are presented.
Date: December 31, 1996
Creator: Huque, Z.; Mei, D. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Slag characterization and removal using pulse detonation for coal gasification. Quarterly report, October 1--December 31, 1996

Description: This report summarizes the costs associated with ash fouling and its removal from the heat exchanger of the Sherburne Co. plant`s 800 MW unit. The lead heat exchanger in the convective pass takes the brunt of the ash accumulation. This study concluded that for the amount of money used one cleaning cycle, 33 pulse detonation units could be purchased.
Date: December 31, 1997
Creator: Huque, Z.; Mei, D.; Biney, P.O. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Slag characterization and removal using pulse detonation for coal gasification

Description: This report is a preliminary economic analysis of the Sherburne Co. plant North State Power. This analysis is made with the cooperation of Joe Brojberg (senior analysis engineer of NSP) and Steve Bension (Slag and ash specialist, President of Microbeam Technologies Incorporated (MTI) of North Dakota) and Paul Johnson of Diamond Power Speciality.
Date: June 25, 1997
Creator: Huque, Z.; Mei, D.; Biney, P.O. & Zhou, J.
Partner: UNT Libraries Government Documents Department

Characterization and optimization of sorbents utilized for emission control during coal gasification. 1997 Fourth quarter research report, October 1, 1997--December 31, 1997

Description: Advanced integrated gasification combined cycle and pressurized fluidized bed combustion power system requires both hot gas desulfurization and particulate filtration to improve system thermal efficiency and overall performance. Few metal oxides were evaluated to be the sorbent candidate for hot gas desulfurization process. The use of waste iron oxide as a disposable metal oxide sorbent will alleviate the constraints imposed on iron oxides including the degradation of sulfur capacity and its physical attrition required for a regenerable sorbent. The very low cost of waste iron oxides and the elimination of the investment associated with sorbent regeneration make it attractive to replace currently developed sorbent candidates. However, the use of waste iron oxides indicates a significant increase of dust loading for particulate filtration. The slower the reaction rate the iron oxide and coal ash mixture is, the longer residence time and higher iron oxide to coal ratio are required. One of the key issue of the use of waste iron oxides as a disposable sorbent material relies on the capability of particulate filtration efficiency. The current back pulse cleaning of the dust cake had been evaluated; and the preliminary test results indicated that the simultaneous operation of hot gas desulfurization and particulate filtration is feasible. A parametric testing will be performed on hot gas desulfurization and particulate independently first. The independent test results will help optimize the test design and evaluation of the integration of hot gas desulfurization testing and particulate filtration testing to be completed in the first two quarters 1998.
Date: December 31, 1997
Creator: Huque, Z.; Mei, D. & Zhou, J.
Partner: UNT Libraries Government Documents Department