Cryogenic thermal control technology summaries

A summarization and categorization is presented of the pertinent literature associated with cryogenic thermal control technology having potential application to in-orbit fluid transfer systems and/or associated space storage. Initially, a literature search was conducted to obtain pertinent documents for review. Reports determined to be of primary significance were summarized in detail. Each summary, where applicable, consists of; (1) report identification, (2) objective(s) of the work, (3) description of pertinent work performed, (4)major results, and (5) comments of the reviewer (GD/C). Specific areas covered are; (1) multilayer insulation of storage tanks with and without vacuum jacketing, (2) other insulation such as foams, shadow shields, microspheres, honeycomb, vent cooling and composites, (3) vacuum jacketed and composite fluid lines, and (4) low conductive tank supports and insulation penetrations. Reports which were reviewed and not summarized, along with reasons for not summarizing, are also listed

Thermal Performance of a Customized Multilayer Insulation (MLI). Design and Fabrication of Test Facility Hardware

The design, fabrication, and assembly of hardware for testing the performance of a customized multilayer insulation are discussed. System components described include the thermal payload simulator, the modified cryoshroud, and a tank back pressure control device designed to maintain a constant liquid boiling point during the thermal evaluation of the multilayer insulation. The thermal payload simulator will provide a constant temperature surface in the range of 20.5 to 417K (37 to 750R) for the insulated tank to view. The cryoshroud was modified to establish a low temperature black body cavity while limiting liquid hydrogen usage to a minimum feasible rate

Thermal performance of a customized multilayer insulation (MLI)

The thermal performance of a LH2 tank on a shroudless vehicle was investigated. The 1.52 m (60 in) tank was insulated with 2 MLI blankets consisting of 18 double aluminized Mylar radiation shields and 19 silk net spacers. The temperature of outer space was simulated by using a cryoshroud which was maintained at near liquid hydrogen temperature. The heating effects of a payload were simulated by utilizing a thermal payload simulator (TPS) viewing the tank. The test program consisted of three major test categories: (1) null testing, (2) thermal performance testing of the tank installed MLI system, and (3) thermal testing of a customized MLI configuration. TPS surface temperatures during the null test were maintained at near hydrogen temperature and during test categories 2 and 3 at 289 K (520R). The heat flow rate through the tank installed MLI at a tank/TPS spacing of 0.457 m was 1.204 watts with no MLI on the TPS and 0.059 watts through the customized MLI with three blankets on the TPS. Reducing the tank/TPS spacing from 0.457 m to 0.152 m the heat flow through the customized MLI increased by 10 percent

Factors that Affect Willingness to Borrow Student Loans among Community College Students

Research suggests that student loan borrowing has increased at the community college level. This trend is worrisome to many, as research is inconclusive regarding whether loans are positively correlated with achieving a college degree. Many also contend that choosing not to borrow a student loan due to loan aversion can negatively impact a student’s chance of reaping the financial benefits of a college degree. This study surveyed three community colleges in the Midwest to better understand how acculturation, time perspective, and financial literacy impact community college students’ willingness to borrow student loans. Except for financial literacy, none of the variables differed significantly across people of African American, Latino, Caucasian, and Asian ancestry. Furthermore, none of the variables correlated significantly with willingness to borrow student loans. Out of the more malleable traits, such as financial literacy, acculturation, and time perspective, only the “present-fatalistic” time domain and financial literacy scores were significantly correlated. These results suggest that community college students are similar to each other in regard to their acculturation, orientation to time, and financial literacy. Furthermore, differences in community college students’ decisions to borrow student loans are more likely due to unique characteristics rather than due to time perspective, acculturation, or financial literacy

Basic Metals. XIV. Synthesis and Crystal Structure of C5_5H5_5(PMe3_3)CoS5_5 : A New Metallapentathia Heterocycle

Der Zweikernkomplex C$_5$H$_5$(PMe$_3$)Co($\mu$-CO)$_2$Mn(CO)C$_5$H$_4$Me (8) reagiert mit stöchiometrischen Mengen S$_8$ in praktisch quantitativer Ausbeute zu C$_5$H$_5$(PMe$_3$)CoS$_5$ (4). Der Koba.ltapentathia-Heterocyclus 4 ist ebenfalls aus C$_5$H$_5$(PMe$_3$)Co(h$^2$-CS$_2$) (5) und S$_8$ zugänglich. 4 kristallisiert monoklin mit den Gitterkonstanten a = 8,467(3) A, b = 12,128(4) A, c = 14,210(4) A und $\beta$ = 102,20(2)°_ Die Sesselform des sechsgliedrigen CoS$_5$-Rings entspricht derjenigen in den bekannten Verbindungen (C$_5$H$_5$)$_2$TiS$_5$ und (C$_5$H$_5$)$_2$VS$_5$ , wobei in 4 der Cyclopentadienylligand die axiale und die Trimethylphosphingruppe die ä.quatoriale Position einnehmen.The dinuclear complex C$_5$H$_5$(PMe$_3$)Co($\mu$-CO)$_2$Mn(CO)C$_5$H$_4$Me (8) reaots with stoichiometric amounts of S$_8$ to form C$_5$H$_5$(PMe$_3$)CoS$_5$ (4) in practica.lly quantitative yields. The cobalt. apentathia heterocycle 4 is a.lso obtained by the reaction of C$_5$H$_5$(PMe$_3$)Co(h$^2$-CS$_2$) (5) with S$_8$, Cry. stals of 4 are monoclinic with a = 8.467(3) A, b = 12.128(4) A, c = 14.210(4) A and $\beta$ = 102.20(2)°. The chair form of the six·membered CoS$_5$ ringcorresponds to that of the compounds (C$_5$H$_5$)$_2$TiS$_5$ and (C$_5$H$_5$)$_2$VS$_5$ In 4, the cyclopentadienyl ligand occupies the axial and the trimethylphosphine group the equatorial position

Applications of the ER-2 meteorological measurement system

The NASA ER-2 aircraft is used as a platform for high altitude atmospheric missions. The Meteorological Measurement System (MMS) was developed specifically for atmospheric research to provide accurate high resolution measurements of pressure, temperature, and the 3-D wind vector with a sampling rate of 5/s. The MMS consist of three subsystems: (1) an air motion sensing system to measure the velocity of the air with respect to the aircraft; (2) a high resolution inertial navigation system (INS) to measure the velocity of the aircraft with respect to the earth; and (3) a data acquisition system to sample, process, and record the measurement quantities. MMS data have been used extensively by ER-2 investigators in elucidating the polar ozone chemistry. Herein, applications on atmospheric dynamics are emphasized. Large scale (polar vortex, potential vorticity, model atmosphere), mesoscale (gravity waves, mountain waves) and microscale (heat fluxes) atmospheric phenomena are investigated and discussed

Unsupervised Learning of Reflexive and Action-Based Affordances to Model Adaptive Navigational Behavior

Here we introduce a cognitive model capable to model a variety of behavioral domains and apply it to a navigational task. We used place cells as sensory representation, such that the cells’ place fields divided the environment into discrete states. The robot learns knowledge of the environment by memorizing the sensory outcome of its motor actions. This is composed of a central process, learning the probability of state-to-state transitions by motor actions and a distal processing routine, learning the extent to which these state-to-state transitions are caused by sensory-driven reflex behavior (obstacle avoidance). Navigational decision making integrates central and distal learned environmental knowledge to select an action that leads to a goal state. Differentiating distal and central processing increases the behavioral accuracy of the selected actions and the ability of behavioral adaptation to a changed environment. We propose that the system can canonically be expanded to model other behaviors, using alternative definitions of states and actions. The emphasis of this paper is to test this general cognitive model on a robot in a real-world environment

The need for robust critique of arts and health research: Dance‐movement therapy, girls, and depression

We examine a highly cited randomized controlled trial on dance-movement therapy with adolescent girls with mild depression and examine its treatment in 14 evidence reviews and meta-analyses of dance research. We demonstrate substantial limitations in the trial which seriously undermine the conclusions reached regarding the effectiveness of dance movement therapy in reducing depression. We also show that the dance research reviews vary substantially in their treatment of the study. Some reviews provide a positive assessment of the study and take its findings at face value without critical commentary. Others are critical of the study, identifying significant limitations, but showing marked differences in Cochrane Risk of Bias assessments. Drawing on recent criticisms of systematic reviewing and meta-analysis, we consider how reviews can be so variable and discuss what is needed to improve the quality of primary studies, systematic reviews, and meta-analyses in the field of creative arts and health