Similitude requirements for hypersonic, rarefied, nonequilibrium flow

Similitude requirements for hypersonic, rarefied flow with nonequilibrium chemistry and vibration are presented. The full Navier-Stokes equations with catalytic or noncatalytic walls and with or without slip conditions are nondimensionalized. The heat transfer coefficient is written in terms of fourteen dimensionless parameters and reduced to four by making the binary scaling assumption. Duplication of blunt and sharp nose heat transfer requires the use of air over a geometrically similar model with the same free stream velocity, wall temperature and product of free stream density and characteristic length. Estimates of this heat transfer coefficient are also presented

Analysis and specification tools in relation to the APSE

Ada and the Ada Programming Support Environment (APSE) specifically address the phases of the system/software life cycle which follow after the user's problem was translated into system and software development specifications. The waterfall model of the life cycle identifies the analysis and requirements definition phases as preceeding program design and coding. Since Ada is a programming language and the APSE is a programming support environment, they are primarily targeted to support program (code) development, tecting, and maintenance. The use of Ada based or Ada related specification languages (SLs) and program design languages (PDLs) can extend the use of Ada back into the software design phases of the life cycle. Recall that the standardization of the APSE as a programming support environment is only now happening after many years of evolutionary experience with diverse sets of programming support tools. Restricting consideration to one, or even a few chosen specification and design tools, could be a real mistake for an organization or a major project such as the Space Station, which will need to deal with an increasingly complex level of system problems. To require that everything be Ada-like, be implemented in Ada, run directly under the APSE, and fit into a rigid waterfall model of the life cycle would turn a promising support environment into a straight jacket for progress

Slip conditions with wall catalysis and radiation for multicomponent, nonequilibrium gas flow

The slip conditions for a multicomponent mixture with diffusion, wall-catalyzed atom recombination and thermal radiation are derived, and simplified expressions for engineering applications are presented. The gas mixture may be in chemical nonequilibrium with finite-rate catalytic recombination occurring on the wall. These boundary conditions, which are used for rarefied flow regime flow field calculations, are shown to be necessary for accurate predictions of skin friction and heat transfer coefficients in the rarefied portion of the space shuttle trajectory

A numerical solution of the Navier-Stokes equations for chemically nonequilibrium, merged stagnation shock layers on spheres and two-dimensional cylinders in air

Results of solving the Navier-Stokes equations for chemically nonequilibrium, merged stagnation shock layers on spheres and two-dimensional cylinders are presented. The effects of wall catalysis and slip are also examined. The thin shock layer assumption is not made, and the thick viscous shock is allowed to develop within the computational domain. The results show good comparison with existing data. Due to the more pronounced merging of shock layer and boundary layer for the sphere, the heating rates for spheres become higher than those for cylinders as the altitude is increased

Protective coatings for composite tubes in space applications

Protective coatings for graphite/epoxy (Gr/Ep) tubular structures for a Manned Space Station truss structure were evaluated. The success of the composite tube truss structure depends on its stability to long-term exposure to the Low Earth Orbit (LEO) environment with particular emphasis placed on atomic oxygen. Concepts for protectively coating Gr/Ep tubes include use of inorganic coated metal foils and electroplating. These coatings were applied to Gr/Ep tubes and then subjected to simulated LEO environmnet to evaluate survivability of coatings and coated tubes. Evaluation included: atomic oxygen resistance, changes in optical properties and adhesion, abrasion resistancem surface preparation required, coating uniformity, and formation of microcracks in the Gr/Ep tubes caused by thermal cycling. Program results demonstrated that both phosphoric and chromic acid anodized Al foil provided excellent adhesion to Gr/Ep tubes and exhibited stable optical properties when subjected to simulated LEO environment. The SiO2/Al coatings speuttered onto Al foils also resulted in an excellent protective coating. Electroplated Ni exhibited unaccepatble adhesion loss to Gr/Ep tubes during atomic oxygen exposure

Drive mechanism for production of simulated human breath

Simulated breath drive mechanism was developed as subsystem to breathing metabolic simulator. Mechanism reproduces complete range of human breath rate, breath depth, and breath waveform, as well as independently controlled functional residual capacity. Mechanism was found capable of simulating various individual human breathing characteristics without any changes of parts

The Impact of Aging and Estrogen Therapy on Synaptic Mitochondrial Bioenergetics in an Alzheimer\u27s Mouse Model

Mitochondrial dysfunction, such as reductions in ATP production via oxidative phosphorylation, is a recognized pathological symptom of neurodegenerative diseases including Alzheimer\u27s disease (AD). One of the known risk factors for the development of AD is the inheritance of a specific genotype of a lipid transporting protein known as apolipoprotein E (apoE). How apoE contributes to the development and progression of AD is poorly understood. The purpose of this study was to determine if a relationship exists between mitochondrial dysfunction and genetic predisposition to AD via apoE. Mitochondrial bioenergetics and enzymatic activity were investigated in an AD mouse model (apoE KO) and in wild-type (WT) mice. Since AD develops with age, mitochondrial function was studied in both young (4-6 months old) and old (12-22 months old) mice. Additionally, estrogen therapy was utilized as a possible therapeutic to prevent mitochondrial dysfunction. We isolated mitochondria located in nerve cell terminals (synaptosomes) using Percoll gradient centrifugation from WT (C57BL/6J) and apoE KO (Apoetn1Unc) mice. Mitochondria were isolated from the following three treatment groups: mice possessing ovaries injected with vehicle control solution (Sham), ovariectomized mice with vehicle control injection (OVX), and ovariectomized mice with 50 ng/g injection of 17β-estradiol (OVX + E2). Mitochondrial function was evaluated based on oxygen consumption of permeabilized and non-permeabilized synaptosomes and was measured using the OROBOROS Oxygraph-2k at 37°C. Succinate dehydrogenase (SDH) and citrate synthase (CS) activity was also assayed to help elucidate the bioenergetic profile of the isolated synaptosomes. Our results revealed no significant differences in oxygen consumption from intact and permeabilized synaptosomes between Sham and OVX young WT and apoE KO mice. Additionally, no significant differences were detected in SDH and CS activity between young WT and apoE KO mice. However, estrogen treatment dramatically increased oxygen consumption and enzymatic activity in apoE KO for all respiration parameters, whereas, a minimal effect was observed in WT mice. No significant differences in oxygen consumption from permeabilized and intact synaptosomes were detected between young and old OVX and OVX + E2 treated mice, but old Sham mice had significantly higher oxygen consumption rates compared to young Sham mice for most all permeabilized parameters in both WT and apoE KO mice. Estrogen treatment had no effect on mitochondrial respiration in old mice, but estrogen treated old apoE KO mice had significantly higher SDH activity compared to its Sham. Increases in respiration and enzymatic activity prompted investigation of mitochondrial quantity via Western blot. We used the voltage dependent-anion-channel (VDAC) as a mitochondrial quantity marker. The results revealed that estrogen treatment increased mitochondrial quantity in estrogen treated young apoE KO and old Sham mice. We speculate that increases in mitochondrial quantity in young apoE KO mice and old Sham mice were due to estrogen and reactive oxygen species (ROS) induced mitochondrial biogenesis, respectively. Our data suggests that predisposition of AD via apoE inheritance is not an underlying source of mitochondrial abnormalities; however, the effectiveness of estrogen as a neuro-therapeutic may be dependent upon an individual\u27s apoE genotype, as well as, their age

A Thermodynamic Analysis of a Primary Waste Stabilization Pond

Traditional design practice for waste stabilization ponds is based upon the premise that sufficient photosynthetic oxygen must be produced within the pond to satisfy oxygen requirements of the incoming waste flow. Thus, because algae production is proportional to pond surface area, surface organic loading rate is a principal design criterion (hydraulic detention time is the other) . That a possible adverse energy trade exists in the sequence of coupled reactions (aerobic waste degradation-photosynthesis) has been largely ignored. This work is focused on quantitatively articulating this energy trade, in terms of algae produced vis a vis waste degraded. This is done by: (1) defining the chemical reactions involved-both stoichiometrically and thermodynamically (the latter in terms of equilibrium conditions), (2) measuring terms in a daily mass balance model of an operating primary pond, and (3) evaluating the algae production potential for the pond studied, based upon available solar insolation. These results define respectively, (1) the calculated absolute lower limit of daily algae synthesis necessary for production of the stoichiometric oxygen to satisfy the daily influent BOD requirement, (2) a measured daily synthesis rate of algae to compare with the daily influent TOC (total organic carbon), under conditions of maximum sunshine in the annual cycle, and (3) the calculated absolute upper limit of daily algae synthesis, through the annual cycle, if all usable solar energy were utilized. Results, for a daily waste inflow of 415 kg Toe, showed: (1) 167 kg per day of algae TOC must be synthesized to provide the stoichiometric oxygen for 415 kg TOC waste, as glucose, (2) measured algae synthesis rate, in early July, was +12,600 kg TOC per day, and (3) algae production potential in early July was 44,000 kg algae TOC per day. The effluent flux was 110 kg TOC per day

The Impact of Aging and Estrogen Therapy on Synaptic Mitochondrial Bioenergetics in an Alzheimer\u27s Mouse Model

Mitochondrial dysfunction, such as reductions in ATP production via oxidative phosphorylation, is a recognized pathological symptom of neurodegenerative diseases including Alzheimer\u27s disease (AD). One of the known risk factors for the development of AD is the inheritance of a specific genotype of a lipid transporting protein known as apolipoprotein E (apoE). How apoE contributes to the development and progression of AD is poorly understood. The purpose of this study was to determine if a relationship exists between mitochondrial dysfunction and genetic predisposition to AD via apoE. Mitochondrial bioenergetics and enzymatic activity were investigated in an AD mouse model (apoE KO) and in wild-type (WT) mice. Since AD develops with age, mitochondrial function was studied in both young (4-6 months old) and old (12-22 months old) mice. Additionally, estrogen therapy was utilized as a possible therapeutic to prevent mitochondrial dysfunction. We isolated mitochondria located in nerve cell terminals (synaptosomes) using Percoll gradient centrifugation from WT (C57BL/6J) and apoE KO (Apoetn1Unc) mice. Mitochondria were isolated from the following three treatment groups: mice possessing ovaries injected with vehicle control solution (Sham), ovariectomized mice with vehicle control injection (OVX), and ovariectomized mice with 50 ng/g injection of 17β-estradiol (OVX + E2). Mitochondrial function was evaluated based on oxygen consumption of permeabilized and non-permeabilized synaptosomes and was measured using the OROBOROS Oxygraph-2k at 37°C. Succinate dehydrogenase (SDH) and citrate synthase (CS) activity was also assayed to help elucidate the bioenergetic profile of the isolated synaptosomes. Our results revealed no significant differences in oxygen consumption from intact and permeabilized synaptosomes between Sham and OVX young WT and apoE KO mice. Additionally, no significant differences were detected in SDH and CS activity between young WT and apoE KO mice. However, estrogen treatment dramatically increased oxygen consumption and enzymatic activity in apoE KO for all respiration parameters, whereas, a minimal effect was observed in WT mice. No significant differences in oxygen consumption from permeabilized and intact synaptosomes were detected between young and old OVX and OVX + E2 treated mice, but old Sham mice had significantly higher oxygen consumption rates compared to young Sham mice for most all permeabilized parameters in both WT and apoE KO mice. Estrogen treatment had no effect on mitochondrial respiration in old mice, but estrogen treated old apoE KO mice had significantly higher SDH activity compared to its Sham. Increases in respiration and enzymatic activity prompted investigation of mitochondrial quantity via Western blot. We used the voltage dependent-anion-channel (VDAC) as a mitochondrial quantity marker. The results revealed that estrogen treatment increased mitochondrial quantity in estrogen treated young apoE KO and old Sham mice. We speculate that increases in mitochondrial quantity in young apoE KO mice and old Sham mice were due to estrogen and reactive oxygen species (ROS) induced mitochondrial biogenesis, respectively. Our data suggests that predisposition of AD via apoE inheritance is not an underlying source of mitochondrial abnormalities; however, the effectiveness of estrogen as a neuro-therapeutic may be dependent upon an individual\u27s apoE genotype, as well as, their age

Simulated breath waveform control

Subsystem was developed which provides twelve waveform controls to breath drive mechanism. Twelve position, magnetically actuated rotary switch is connected to one end of crankshaft drive, such that it makes one complete revolution for each simulated breath. Connections with common wired point are included in modifications made to standard motor speed controller