Modeling Instructor Training Preparation in a Simulation Flight Training Program

The current research deals with planning problems related to instructors training in simulator flight training programs. It is a part of our development work in optimal training programs to support the cost effective design of instructor/operator stations(IOS). A flight simulator is a complex device which can be used to train students and instructors, whose training requirements and methodologies are quite different. This paper deals with this complex man-machine interface planning problem, presents a model for the instructors training process, and develops a methodology for determining optimal training plans.     

In vitro bioactivity evaluation of nano- and micro-crystalline anodic TiO2: HA formation,cellular affinity and organ culture

Anodization is an easily viable technique useful for producing TiO₂ coatings on titanium substrates. Nano-crystalline anodic TiO₂ structure was produced on titanium at 20 V using 1 M Na₂SO₄ and 0.5% NaF and consolidated by a further heat-treatment. Micro-crystalline anodic TiO₂ was produced on titanium by applying a galvanostatic current density of 70 A/m² in water medium. To assess the usefulness of these nano- and micro-oxides for bone implant stability, physical properties and bone in vitro bioactivity including HA formation, cellular affinity and mouse-tissue morphogenesis, were evaluated. Bioactivity of the different anodic surfaces was evaluated by treating them in a simulated body fluid (SBF) to form hydroxyapatite (HA) and the rates of HA formation were compared. Deposits of HA could be seen on the nano-oxide surface within 7 days, whereas HA was detected only after 14 days on the micro-oxide surface. In vitro cell culture tests done using mouse osteoblasts indicated that the nano-oxides showed statistically significant cell activity than the micro-oxides and the machined titanium. Branching morphogenesis test done for 72 h on these surfaces showed more branching on the micro- and nano-oxides as compared with titanium surface.     

Effect of lipid excipients on in vitro pancreatic lipase activity

PURPOSE: To study the effects of two lipid excipients, Peceol and Gelucire 44/14 on the in vitro pancreatic lipase activity. METHODS: A 50 microL reaction mixture, consisting of 45 microL (3H) triolein as the radiolabeled substrate, 2.5 microL Peceol or Gelucire 44/14 (0.05-0.5%), either alone or in combination, 2.5 microL colipase (100 microg/mL), and 2.5 microL pancreatic lipase (1 mg/mL), was incubated for 10 min at room temperature. At the end of incubation, the reaction was stopped by the addition of an extraction solvent containing chloroform, methanol, and n-heptane (12.5:14:10), and the mixture vortexed briefly. Subsequently, 250 microL of 50 mM sodium carbonate was added and the aqueous and organic phase separated by centrifugation for 5 min at 1000 g. One hundred microliters of the supernatant was transferred to a scintillation counter and then radioactivity measured after the addition of 3.6 mL of scintillation fluid. Pancreatic lipase activity was determined by measuring the amount of free fatty acid released into the incubation medium and expressed as micromol free fatty acid released/min. RESULTS: When used alone, Peceol inhibited the pancreatic lipase activity significantly in a concentration-dependent manner, with a maximum inhibition of 57% at 0.4% of the excipient [p < 0.05, one-way analysis of variance (ANOVA)]. Similarly, Gelucire 44/14 alone caused inhibition of lipase activity in a concentration-dependent manner. However, the maximum inhibition (30%) was smaller in magnitude compared with the former agent. When the two excipients were used in combination, the inhibitory effects on the enzyme activity were similar to those observed with the individual agents (p < 0.05, one-way ANOVA). However, the maximum inhibition of 30% was lower than that observed with Peceol alone. CONCLUSIONS: The results from this study suggest that these lipid excipients inhibit in vitro pancreatic lipase activity and should be taken into consideration when developing oral formulations using these agents.     

Microstructural developments in Mg-Ti-PSZ systems

The microstructure of titania-added Mg-partially-stabilized zirconia (PSZ) is dramatically influenced by thermal treatments. Effects of various sintering, heat-treatment and thermal shock cycling parameters on the microstructure of the Mg-Ti-PSZ system are described. Conditions favourable for the growth of needle-like Ti-rich reinforcements in highly thermalshock-resistant Mg-Ti-PSZ ceramics are identified. TiO₂ seems to play a catalytic role in the formation of Zr-rich networks during high-temperature (1700°C) sintering of the Mg-Ti-PSZ system, quite similar to those found in Mg-PSZ, heat-treated above 1300 °C.     

Multi-grid domain decomposition approach for solution of Navier–Stokes equations in primitive variable form

A new multi-grid (two-grid) pseudospectral element method has been carried out for solution of incompressible flow in terms of primitive variable formulation. The main objective of the proposed method is to apply the multi-grid technique solving the incompressible flow problems associated with three commonly encountered multi-grid environments. In domain decomposition terminology, it includes (I) partially overlapped subdomains, each of which has same types of grids; (II) partially overlapped subdomains, each of which has different types of grids; (III) local adaptive subdomains fully overlapped with the original computational domain (composite grids). The approach for flow problems, complex geometry or not, is to first divide the computational domain into a number of subdomains with the inter-overlapping area (partially or fully overlapped). In categories I and II, the fine-grid or coarse-grid subdomains can be defined by their representation, while in category III the fine-grid or coarse-grid subdomains are defined as usual. Next, implement the Schwarz Alternating Procedure (SAP) to exchange the data among subdomains, where the coarse-grid correction is used to remove the high frequency error that occurs when the data interpolation from the fine-grid subdomain to the coarse-grid subdomain is conducted. The strategy behind the coarse-grid correction is to adopt the operator of the divergence of velocity field, which intrinsically links the pressure equation, into this process. The solution of each subdomain can be efficiently solved by the direct (or iterative) eigenfunction expansion technique or preconditioned method with the least storage requirement, i.e. O(N²) in 2-D. Numerical results of (i) driven cavity flow (Re = 100,400) with Cartesian grids (category I) in each subdomain, (ii) driven cavity flow (Re = 3200) with local adaptive grids (category III) in each subdomain, and (iii) flow over a cylinder (Re = 250) with ‘O’ grids in one subdomain and Cartesian grids in another (category II) will be presented in the paper to account for the versatility of the proposed multi-grid method.     

Self-assembled tungsten oxide nanowires by electron beam assisted rapid thermal annealing

We report on the fabrication of WO₃ nanowires on Si (100) substrate using nickel catalyzed electron beam assisted rapid thermal annealing process. A 7 nm thick W layer deposited on the nickel coated substrate was annealed under high vacuum using electron beam (3 keV) for 30, 60 and 90 s. The nickel activates the growth of tungsten nanowires with a high aspect ratio and subsequently is oxidized due to the high refractory nature of tungsten under exposure to oxygen gas. The resulting changes in surface morphology, oxidization state and elemental composition of WO₃ nanowires were investigated systematically. The oxidization of metallic tungsten nanowire was found to depend on the annealing time.     

Determination of preservative and antimicrobial compounds in fish from Manila Bay, Philippines using ultra high performance liquid chromatography tandem mass spectrometry, and assessment of human dietary exposure

Ultra high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of four paraben preservatives (methyl, ethyl, propyl and butyl) and two antimicrobial agents (triclosan and triclocarban) belonging to personal care products (PCPs) in 20 species of fish from Manila Bay (Philippines) was performed. Detection of PCPs with greater frequency indicates the ubiquitous contamination of Manila Bay. Concentrations of total paraben were one order of magnitude higher than the antimicrobials in almost all fish, except in Stolephorus indicus and Leiognathus equulus. A positive correlation was observed between parabens concentration and fish length (r = 0.31-0.49; p<0.05 to <0.001) and fish weight (r = 0.28-0.49; p<0.05 to <0.001), but not for the antimicrobials. The estimated dietary exposure values of the four parabens in the Philippines through fish is four orders of magnitude lower than the acceptable daily intake (ADI) of 10mg/kg/day, but the values of antimicrobials are just half of the ADI of TCS. To our knowledge, this is the first report of PCPs contamination in fish from Philippines.     

Differences in lipoprotein lipid concentration and composition modify the plasma distribution of cyclosporine

PURPOSE: The purpose of this study was to define the relationship between lipoprotein (LP) lipid concentration and composition and the distribution of cyclosporine (CSA) in human plasma. METHODS: 3H-CSA LP distribution was determined in normolipidemic human plasma that had been separated into different LP and lipoprotein-deficient plasma (LPDP) fractions by either affinity chromatography coupled with ultracentrifugation, density gradient ultracentrifugation or fast protein liquid chromatography. 3H-CSA LP distribution (at a concentration of 1000 ng/ml) was also determined in patient plasma samples with defined dyslipidemias. Furthermore, 3H-CSA LP distribution was determined in patient plasma samples of varying LP lipid concentrations. Following incubation, the plasma samples were separated into their LP and LPDP fractions by sequential phosphotungistic acid precipitation in the dyslipidemia studies and by density gradient ultracentrifugation in the specific lipid profile studies and assayed for CSA by radioactivity. Total plasma and lipoprotein cholesterol (TC), triglyceride (TG) and protein (TP) concentrations in each sample were determined by enzymatic assays. RESULTS: When the LP distribution of CSA was determined using three different LP separation techniques, the percent of CSA recovered in the LP-rich fraction was greater than 90% and the LP binding profiles were similar with most of the drug bound to plasma high-density (HDL) and low-density (LDL) lipoproteins. When 3H-CSA was incubated in dyslipidemic human plasma or specific patient plasma of varying LP lipid concentrations the following relationships were observed. As the very low-density (VLDL) and LDL cholesterol and triglyceride concentrations increased, the percent of CSA recovered within the VLDL and LDL fractions increased. The percent of CSA recovered within the HDL fraction significantly decreased as HDL triglyceride concentrations increased. The percent of CSA recovered in the LPDP fraction remained constant except in hypercholesterolemic/hypertriglyceridemic plasma where the percent of CSA recovered decreased. Furthermore, increases in VLDL and HDL TG/TC ratio resulted in a greater percentage of CSA recovered in VLDL but less in HDL. CONCLUSIONS: These findings suggest that changes in the total and plasma LP lipid concentration and composition influence the LP binding of CSA and may explain differences in the pharmacological activity and toxicity of CSA when administered to patients with different lipid profiles.     

Effect of sintering zirconia with calcia in very low partial pressure of oxygen

Samples of zirconia containing 0, 8 and 15 mol % calcia were sintered in very low partial pressure of oxygen ( 10^–6 Pa) and the resulting phases, lattice parameters and electrical conductivity studied. The cubic phase was found to be partially stabilized in the calcia-free samples while complete stabilization occurred in the samples containing 8 and 15 mol calcia. The lattice parameter of the cubic phase showed dependence on the calcia content and the concentration of vacancies at the anion sites. The concentration of these vacancies in the calcia-containing samples is estimated to be 21 % and is limited by the appearance of metallic zirconium located in isolated pockets. Electrical conductivity measurements also indicated that the metallic phase was not continually connected. A peak and a minimum in the conductivity-temperature plot are believed to be due to the removal of excess oxygen vacancies introduced during sintering.     

Characteristics of a typical lifting symmetric supercritical airfoil

The theoretical aerodynamic characteristics of a typical lifting symmetric supercritical airfoil demonstrating its superiority over thenaca 0012 airfoil from which it was derived are presented in this paper. Further, limited experimental results confirming the theoretical inference are also presented. Invited Lecture given at the 3rd Asian Congress on Fluid Mechanics, held in Tokyo during 1–5 September, 1986