Showing papers by "Missouri University of Science and Technology published in 1996"
TL;DR: In this article, it was shown that unique defect thermodynamics and transport properties result for oxides of a few nanometers crystallite size, which are attributed to a dominant role of interfacial defect formation.
Abstract: It is shown that unique defect thermodynamics and transport properties result for oxides of a few nanometers crystallite size. Fully‐dense CeO2−x polycrystals of ∼10 nm grain size were synthesized, and their electrical properties compared with those of samples coarsened from the same material. The nanocrystals showed reduced grain boundary resistance, 104 higher electronic conductivity, and less than one‐half the heat of reduction of its coarse‐grained counterpart. These properties are attributed to a dominant role of interfacial defect formation.
354 citations
TL;DR: This survey concentrates mainly on image analysis and fault detection strategies; these also include state-of-the-art techniques.
353 citations
TL;DR: Soil MechanicsSoil mechanics in engineering practiceGeotechnical engineering applied Soil Mechanics and Foundation Engineering Volume 3, 2nd ed. as mentioned in this paper, 2.5].
Abstract: Soil MechanicsSoil Mechanics in Engineering PracticeGeotechnical Engineering Applied Soil Mechanics and Foundation Engineering Volume 3Geotechnical EngineeringSoil mechanics in engineering practice, 2nd edSoil Mechanics in Engineering PracticeUnsaturated Soil Mechanics in Engineering PracticePile Foundations in Engineering PracticeGeotechnical Engineering Applied Soil Mechanics and Foundation Engineering Volume 6Erdbaumechanik auf bodenphysikalischer grundlageSoil Mechanics in Engineering Practice [by] Karl Terzaghi [and] Ralph B. PeckGeotechnical Engineering HandbookTHE LEGAL ASPECTS OF FOUNDATION ENGINEERING PRACTICEPAPERS PRESENTED22ND ANNUAL SOIL MECHANICS AND FOUNDATION ENGINEERING CONFERENCESOIL MECHANICS AND FOUNDATIONS TECHNICAL DIVISION OF KANSAS CITY SECTION, AMERICAN SOCIETY OF CIVIL ENGINEERSDEPARTMENT OF CIVIL ENGINEERING, UNIVERSITY OF KANSAS.Geotechnical EngineeringSoil Mechanics and Foundation Engineering, 2eSoil Mechanics in Engineering PracticeSoil Mechanics in Engineering PracticeGeotechnical Engineering Applied Soil Mechanics and Foundation Engineering Volume 1Soil Mechanics in Engineering PracticeGeotechnical EngineeringSoil Mechanics FundamentalsBerechnung von Behältern nach neueren analytischen und graphischen MethodenGeotechnical Engineering Applied Soil Mechanics and Foundation Engineering Volume 4Soil Mechanics in Engineering PracticeSoil MechanicsUnsaturated Soil Mechanics in Geotechnical PracticeSoil Mechanics in Engineering PracticeUnsaturated Soil Mechanics from Theory to PracticeSoil MechanicsSoil Mechanics in Engineering PracticeAdvanced Geotechnical AnalysesNotes on Important Points in \"Soil Mechanics in Engineering Practice\" by Terzaghi and PeckSoil Mechanics in Engineering PracticeTheoretische BodenmechanikSoil MechanicsDie Bodenmechanik in der BaupraxisMunicipal Engineering PracticeSoil Mechanics Found in Engineering DesignPractical Problems in Soil Mechanics and Foundation Engineering: Physical characteristics of soils, plasticity, settlement calculations, interpretation of in-situ testsSoil Mechanics in Engineering Practice
297 citations
TL;DR: The glycopeptide antibiotic teicoplanin is shown to be a highly effective stationary phase chiral selector for the resolution of underivatized amino-acid and imino-acid enantiomers and the enantioselective separation mechanism is examined using both molecular modeling and retention data.
279 citations
TL;DR: A dual neural network architecture for the solution of aircraft control problems is presented and results show that this network architecture yields optimal control over the entire range of training, so that the neural network can function as an autopilot.
Abstract: A dual neural network architecture for the solution of aircraft control problems is presented. The neural network structure, consisting of an action network and a critic network, is used to approximately solve the dynamic programming equations associated with optimal control with a high degree of accuracy. Numerical results from applying this methodology to optimally control the longitudinal dynamics of an aircraft are presented. The novelty in this synthesis of the optimal controller network is that it needs no external training inputs; it needs no a priori knowledge of the form of control. Numerical experiments with neural-network-based control as well as other pointwise optimal control techniques are presented. These results show that this network architecture yields optimal control over the entire range of training. In other words, the neural network can function as an autopilot. A scalar problem is also used in this study for easier illustration of the solution development.
267 citations
TL;DR: The relationship between the various expressions that can be used to calculate binding constants with CE is shown and the advantages, limitations and proper use of the various approaches are discussed.
247 citations
TL;DR: Ristocetin A appears to have the greatest applicability for CE enantioseparations and the empirically useful "principle of complementary separations", in which a partial resolution with one chiral selector can be brought to baseline with one of the others.
Abstract: The structurally related glycopeptide antibiotics vancomycin, ristocetin A, and teicoplanin can all be used as chiral selectors in capillary electrophoresis (CE). Both experimental and modeling studies were done to elucidate their similarities and differences. There are identifiable morphological differences in the aglycon macrocyclic portions of these three compounds. In addition, there are other structural distinctions that can affect their CE enantioselectivity, migration times, and efficiency. Teicoplanin is the most distinct of the three and is the only one that is surface active. Its aggregational properties appear to affect its enantioselectivity among other things. The similar but not identical structures of the three glycopeptides produce similar but not identical enantioselectivities. This leads to the empirically useful “principle of complementary separations”, in which a partial resolution with one chiral selector can be brought to baseline with one of the others. Overall, ristocetin A appears...
214 citations
TL;DR: A thrust force controller was developed to minimize the delamination while drilling a graphite-epoxy laminate and experimental results verifying the validity of this control approach as well as the robustness of the design are presented.
Abstract: Delamination is a well-recognized problem associated with drilling fiber-reinforced composite materials (FRCMs). The most noted problems occur as the drill enters and exits the FRCM. Since drilling is often a final operation during assembly, any defects introduced in parts through the drilling process that result in the part being rejected represent an expensive loss. Studies based on linear-elastic fracture mechanics theory have proposed critical cutting and thrust forces in the various drilling regions that can be used as a guide in preventing crack growth or delamination. Using these critical force curves as a guide, a thrust force controller was developed to minimize the delamination while drilling a graphite-epoxy laminate. A neural network control scheme was implemented which required a neural network identifier to model the drilling dynamics and a neural network controller to learn the relationship between feed rate and the desired thrust force. Experimental results verifying the validity of this control approach as well as the robustness of the design are presented. Visual measurements of the delamination zones were used to quantify the benefits of the thrust force controlled drilling process versus the conventional constant feed rate drilling process.
211 citations
Journal Article•
TL;DR: In this paper, the structural differences between vancomycin, ristocetin A, and teicoplanin were investigated as chiral selectors in capillary electrophoresis (CE).
Abstract: The structurally related glycopeptide antibiotics vancomycin, ristocetin A, and teicoplanin can all be used as chiral selectors in capillary electrophoresis (CE). Both experimental and modeling studies were done to elucidate their similarities and differences. There are identifiable morphological differences in the aglycon macrocyclic portions of these three compounds. In addition, there are other structural distinctions that can affect their CE enantioselectivity, migration times, and efficiency. Teicoplanin is the most distinct of the three and is the only one that is surface active. Its aggregational properties appear to affect its enantioselectivity among other things. The similar but not identical structures of the three glycopeptides produce similar but not identical enantioselectivities. This leads to the empirically useful “principle of complementary separations”, in which a partial resolution with one chiral selector can be brought to baseline with one of the others. Overall, ristocetin A appears...
200 citations
TL;DR: Results suggest that lead-induced oxidative stress in vivo can be mitigated by pharmacologic interventions, which encompass both chelating as well as thiol-mediated antioxidant functions.
172 citations
TL;DR: Experimental and theoretical research and development studies are preposed and presented in important areas of the freeze drying process, and the practical importance of the synergistic integration of advanced theoretical models and experiments is indicated as mentioned in this paper.
Abstract: Experimental and theoretical research and development studies are preposed and presented in important areas of the freeze drying process. The practical importance of the synergistic integration of advanced theoretical models and experiments is indicated, and the potential contributions of the proposed
TL;DR: In this article, a differential thermal analysis (DTA) method has been developed that identifies and distinguishes surface and internal (volume) crystallization in glasses, which is fast, convenient and requires only a small quantity of sample, ∼500 mg, to identify the dominant crystallization, surface versus internal, in the glass.
Abstract: A differential thermal analysis (DTA) method has been developed that identifies and distinguishes surface and internal (volume) crystallization in glasses. This method is fast, convenient, and requires only a small quantity of sample, ∼500 mg, to identify the dominant crystallization, surface versus internal, in the glass. In this method, either the maximum height of the DTA crystallization peak, (δT”)p, or the ratio T2p/(ΔT)p, where Tp is the temperature at (δT)p and (ΔT)p the peak half width, is plotted as a function of particle size. The composition of the glasses that have been investigated in the present work include (in mol%) 33.3BaO 66.7SiO2 (BS2), 20Na2O-80TeO2 (NT4), 22.2PbOll.lNb2O5 66.7TeO2 (PNT), 66.7PbO10.0Bi2O3-23.3Ga2O3 (PBG), and xLi2O(100 - x)SiO2 (lithium silicate, x = 33.3, 35, 37, and 40 mol%). Both (δT)p and T2p/(ΔT)p decrease with increasing particle size when surface crystallization is the dominant mechanism and increase when internal crystallization becomes predominant. The surface and internal crystallization have been identified by crystallizing the glasses at temperatures, as determined by DTA, and then examining the microstructure by scanning electron microscopy. The temperature at the crystallization peak maximum, Tp, shows no dependence on the crystallization mechanism (surface versus internal) and increases with increasing particle size for all the preceding glasses.
TL;DR: In this article, a powder of yttrium aluminum garnet (YAG) with the stoichiometric composition 3Y2O3·5AI2O 3 was prepared by a solgel technique and dried by supercritical extraction with CO2.
Abstract: Gels of yttrium aluminum garnet (YAG) with the stoichiometric composition 3Y2O3·5AI2O3, were prepared by a sol-gel technique and dried by supercritical extraction with CO2. Powders were produced by lightly grinding the dried gels. Crystallization of the powder occurred at ≈900°C and within the limits of detection, the X-ray diffraction pattern of the crystallized material was identical to that of the stoichiometric composition. Powder compacts with a green density of ≈0.50 of the theoretical were sintered to nearly full density in O2 during constant heating rate sintering at 5 °C min−1 to 1600 °C. This is better than the density obtained with powders from a similar gel dried conventionally (by evaporation of the liquid) and considerably better than that obtained with powders prepared by solid state reaction. The room temperature flexural strength and fracture toughness of the material fabricated from the supercritically dried gels were 190 MPa and 2.2 MPa.m1/2, respectively. These strength and fracture toughness values are higher than those reported in other studies for YAG produced by the sintering route.
TL;DR: A trisorganotin-substituted Keggin tungstosilicate heteropolyanions have been synthesized and characterized by elemental analysis, infrared and Mossbauer spectroscopy, multinuclear NMR, and X-ray crystallography as mentioned in this paper.
Abstract: Eight tris(organotin)-substituted Keggin tungstosilicate heteropolyanions have been synthesized and characterized by elemental analysis, infrared and Mossbauer spectroscopy, multinuclear NMR, and X-ray crystallography. The new anions contain alpha- or beta-SiW(9)O(34)(10)(-) moieties and are of two structural types, [(RSn)(3)(SiW(9)O(37))](7)(-) (R, isomer: Ph, alpha-, 1; n-Bu, alpha-, 2; Ph, beta-, 3; n-Bu, beta-, 4) and [(RSnOH)(3)(SiW(9)O(34))(2)](14)(-) (Ph, alpha-, 5; n-Bu, alpha-, 6; Ph, beta-, 7; n-Bu, beta-, 8). Crystals of Cs(4)H(3)[(PhSn)(3)(SiW(9)O(37))].8H(2)O (anion 3) are monoclinic, space group C2/c, with lattice constants a = 48.91(2) A, b = 12.111(3) A, c = 20.334(9) A, beta = 102.30 degrees, and Z = 8. The anion has nominal C(3)(v)() symmetry and has a structure with three corner-shared WO(6) octahedra of the beta-Keggin anion replaced by three PhSnO(5) groups. Crystals of Cs(9)H(5)[(BuSnOH)(3)(SiW(9)O(34))(2)].36H(2)O (anion 6) are tetragonal, space group Pf2(1)m, with lattice constants a = b = 29.005(4) A, c = 13.412(4) A, and Z = 4. The anion has the anticipated D(3)(h)() symmetry and contains three BuSnOH groups sandwiched between A,alpha-SiW(9)O(34)(10)(-) anions.
TL;DR: In this article, a mathematical model based on a layerwise theory is developed for laminated composite beams with piezoelectric actuators, and a finite element model is developed.
TL;DR: In this article, cerium(IV) oxide films were deposited electrochemically on 430 stainless steel and (100)-oriented highly doped degenerate p-type single-crystal silicon in aqueous solution by the electrogeneration of base method.
TL;DR: In this article, a differential thermal analysis (DTA) method was developed that identifies and distinguishes surface and internal (bulk) crystallization that occurs during the crystallization of a glass.
TL;DR: Teicoplanin is the third in a series of macrocyclic glycopeptide antibiotics that has been evaluated as a chiral selector in capillary electrophoresis (CE) and exhibited some features that were not noted with the other glycopeptic antibiotics.
TL;DR: In this paper, the friction and wear characteristics of control and hybrid composites containing milled E-glass or steel were determined at various counterface speeds and temperatures using a Chase friction tester.
TL;DR: In this paper, a prestrained shape memory alloy (SMA) was used to reduce the deformation and stresses in cross-ply composite plates subjected to low velocity impact.
Abstract: The paper presents an approach to the problem of optimum design of composite plates subjected to low velocity impact. The deflections and stresses are reduced by employing prestrained shape memory alloy (SMA) fibers which are in the martensitic phase when embedded within the plate. At an elevated temperature, the SMA fibers transform into the austenitic phase and tend to contract. However, due to a constraint, the contraction is either completely prevented or reduced resulting in significant tensile recovery stresses. This tension reduces deformations and stresses in the plate subjected to low-velocity impact. The solution in the paper addresses an impact of cross-ply plates with SMA fibers embedded within the layers oriented in both directions. An approach to optimization considered in the paper involves variations of the volume fractions of SMA fibers in each direction subject to a constraint on the total volume of the shape memory alloy. It is shown that an application of SMA fibers can significantly reduce deflections and stresses. A further benefit can be achieved by an optimization of a distribution of volume fractions of SMA fibers between the layers.
TL;DR: In this paper, the authors examined both cognitive and affective outcomes associated with knowledge map processing and found that the positive impact of knowledge maps goes beyond objective cognitive outcomes to include subjective ratings of concentration and motivation as well.
TL;DR: In this article, the sintering of ultrafine γ-Al2O3 powder (particle size ∼10-20 nm) prepared by an inert gas condensation technique was investigated in air at a constant heating rate of 10°C/min.
Abstract: The sintering of ultrafine γ-Al2O3 powder (particle size ∼10–20 nm) prepared by an inert gas condensation technique was investigated in air at a constant heating rate of 10°C/min. Qualitatively, the kinetics followed those of transition aluminas prepared by other methods. Measurable shrinkage commenced at ∼ 1000°C and showed a region of rapid sintering between ∼1125° and 1175°C followed by a transition to a much reduced sintering rate at higher temperatures. Starting from an initial density of ∼0.60 relative to the theoretical value, the powder compact reached a relative density of 0.82 after sintering to 1350°C. Compared to compacts prepared from the as-received powder, dispersion of the powder in water prior to compaction produced a drastic change in the microstructural evolution and a significant reduction in the densification rate during sintering. The incorporation of a step involving the rapid heating of the loose powder to ∼1300°C prior to compaction (which resulted in the transformation to α-Al2O3) provided a method for significantly increasing the density during sintering.
TL;DR: In this paper, the influence of preannealing treatments on the polymorphic crystallization of lithium disilicate glasses is examined and the first systematic investigations of particle size effects on the non-isothermal transformation behavior are presented and discussed.
Abstract: The influence of preannealing treatments on the polymorphic crystallization of lithium disilicate glasses is examined. As expected, glasses heated at different rates through the temperature range where there is significant nucleation develop widely different numbers of nuclei. This can dramatically influence the stability and transformation characteristics of the annealed glass. Non-isothermal differential scanning calorimetry (DSC) and differential thermal analysis (DTA) measurements are demonstrated to be useful to probe the nucleation behavior. The first systematic investigations of particle size effects on the non-isothermal transformation behavior are presented and discussed. Based on DTA and microscopy experiments, we show that small particles of lithium disilicate glasses crystallize primarily by surface crystallization. The relative importance of surface versus volume crystallization is examined by varying particle size, by introducing nucleating agents and by exposing glasses to atmospheres of different water content. These data are analyzed quantitatively using a numerical model developed in a second paper following in this volume.
01 May 1996
TL;DR: An analytic framework is developed for the specification and analysis of imprecise requirements using fuzzy logic and this formal foundation facilitates the inference of relationships between requirements for detecting implicit conflicts, to assess the relative priorities of requirements for resolving conflicts, and to assessment the effect of a requirement change.
Abstract: There are at least three challenges with requirements analysis. First, it needs to bridge informal requirements, which are often vague and imprecise, to formal specification methods. Second, requirements often conflict with each other. Third, existing formal requirement specification methodologies are limited in supporting trade-off analysis between conflicting requirements and identifying the impact of a requirement change to the rest of the system. In this paper, an analytic framework is developed for the specification and analysis of imprecise requirements. In this framework, the elasticity of imprecise requirements is captured using fuzzy logic and the relationships between requirements are formally classified into four categories: conflicting, cooperative, mutually exclusive and irrelevant. This formal foundation facilitates the inference of relationships between requirements for detecting implicit conflicts, to assess the relative priorities of requirements for resolving conflicts, and to assess the effect of a requirement change.
TL;DR: An amine moiety that provides one of the more important enantioselective interactions was identified and was illustrated using a color-coded, space-filling model of the X-ray crystal structure of the copper-vancomycin complex.
01 Jan 1996
TL;DR: In this paper, a qualitative spectral analysis for a class of second order difference equations is given, and the analysis of equations in this class is the observation that real-valued solutions exhibit a type of stable asymptotic behavior for certain real values of the spectral parameter.
TL;DR: The results suggest that NAC can confer protection against lead-induced oxidative stress to CHO cells, possibly through the enhancement of the cell’s own antioxidant defense mechanisms.
TL;DR: It is found that the number and position of glycyl moieties affect the retentions and enantioselectivities of FMOC derivatized glycyl containing peptides.