Mars Surface Mobility Leading to Sustainable Exploration

A Mars rocket-propelled hopper concept was evaluated for feasibility through analysis and experiments. The approach set forth in this paper is to combine the use of in-situ resources in a new Mars mobility concept that will greatly enhance the science return while providing the first opportunity towards reducing the risk of incorporating ISRU into the critical path for the highly coveted, but currently unaffordable, sample return mission. Experimental tests were performed on a high-pressure, self-throttling gaseous oxygen/methane propulsion system to simulate a two-burn-with-coast hop profile. Analysis of the trajectory, production plant requirements, and vehicle mass indicates that a small hopper vehicle could hop 2 km every 30 days with an initial mass of less than 60 kg. A larger vehicle can hop 15 km every 30 to 60 days with an initial mass of 300 to 430 kg

Mars ISRU for Production of Mission Critical Consumables - Options, Recent Studies, and Current State of the Art

In 1978, a ground breaking paper titled, "Feasibility of Rocket Propellant Production on Mars" by Ash, Dowler, and Varsi discussed how ascent propellants could be manufactured on the Mars surface from carbon dioxide collected from the atmosphere to reduce launch mass. Since then, the concept of making mission critical consumables such as propellants, fuel cell reactants, and life support consumables from local resources, commonly known as In-Situ Resource Utilization (ISRU), for robotic and human missions to Mars has been studied many times. In the late 1990's, NASA initiated a series of Mars Human Design Reference Missions (DRMs), the first of which was released in 1997. These studies primarily focused on evaluating the impact of making propellants on Mars for crew ascent to Mars orbit, but creating large caches of life support consumables (water & oxygen) as a backup for regenerative life support systems for long-duration surface stays (>500 days) was also considered in Mars DRM 3.0. Until science data from the Mars Odyssey orbiter and subsequent robotic missions revealed that water may be widely accessable across the surface of Mars, prior Mars ISRU studies were limited to processing Mars atmospheric resources (carbon dioxide, nitrogen, argon, oxygen, and water vapor). In December 2007, NASA completed the Mars Human Design Reference Architecture (DRA) 5.0 study which considered water on Mars as a potential resource for the first time in a human mission architecture. While knowledge of both water resources on Mars and the hardware required to excavate and extract the water were very preliminary, the study concluded that a significant reduction in mass and significant enhancements to the mission architecture were possible if Mars water resources were utilized. Two subsequent Mars ISRU studies aimed at reexamining ISRU technologies, processing options, and advancements in the state-of-the-art since 2007 and to better understand the volume and packaging associated with Mars ISRU systems further substantiated the preliminary results from the Mars DRA 5.0 study. This paper will provide an overview of Mars ISRU consumable production options, the analyses, results, and conclusions from the Mars DRA 5.0 (2007), Mars Collaborative (2013), and Mars ISRU Payload for the Supersonic Retro Propulsion (2014) mission studies, and the current state-of-the-art of Mars ISRU technologies and systems. The paper will also briefly discuss the mission architectural implications associated with Mars resource and ISRU processing options

Advanced Manifolds for Improved Solid Oxide Electrolyzer Performance

An investigation was conducted to see if additive manufacturing could be used to fabricate more efficient manifold designs for improved flow, reduced stresses, and decreased number of joints to be sealed for a solid oxide electrolyzer used to convert carbon dioxide to oxygen. Computational flow and mechanical modeling were conducted on a NASA Glenn Research Center patented cell and stack design with the potential to achieve a 3-4 times mass reduction. Various manifold designs were modeled, and two were downselected to be fabricated and tested. Some benefit was seen in a baffled manifold design, which directed incoming flow more effectively into the flow channels, compared to the original design, where the flow spent more time within the manifold itself. Flow measurements indicated some non-uniformity of flow across the channels at higher flow rates, which were not predicted by the model. Some possible explanations for the differences are discussed

Women's dietary changes before and during pregnancy: A systematic review

Background: dietary intake before and during pregnancy has significant health outcomes for both mother and child, including a healthy gestational weight gain. To ensure effective interventions are successfully developed to improve dietary intake during pregnancy, it is important to understand what dietary changes pregnant women make without intervention. Aims: to systematically identify and review studies examining women's dietary changes before and during pregnancy and to identify characteristics of the women making these changes. Methods: a systematic search strategy was employed using three databases (Web of Science, CINAHL and PubMed) in May 2016. Search terms included those relating to preconception, pregnancy and diet. All papers were quality assessed using the Scottish Intercollegiate Guidelines Network methodology checklist for cohort studies.The search revealed 898 articles narrowed to full-text review of 23 studies. In total, 11 research articles were included in the review, describing nine different studies. The findings were narratively summarised in line with the aims of the review. Findings: the included studies showed marked heterogeneity, which impacts on the findings. However, the majority report an increase in energy intake (kcal or kJ) during pregnancy. Of the studies that reported changes through food group comparisons, a majority reported a significant increase in fruit and vegetable consumption, a decrease in egg consumption, a decrease in fried and fast food consumption and a decrease in coffee and tea consumption from before to during pregnancy. The characteristics of the women participating in these studies, suggest that age, education and pregnancy intention are associated with healthier dietary changes; however these factors were only assessed in a small number of studies. Key conclusions: the 11 included articles show varied results in dietary intake during pregnancy as compared to before. More research is needed regarding who makes these healthy changes, this includes consistency regarding measurement tools, outcomes and time points. Implications for practice: Midwives as well as intervention developers need to be aware of the dietary changes women may spontaneously engage in when becoming pregnant, so that care and interventions can build on these

Effects of an interactive CD-program on 6 months readmission rate in patients with heart failure – a randomised, controlled trial [NCT00311194]

BACKGROUND: Disease-management programmes including patient education have promoted improvement in outcome for patients with heart failure. However, there is sparse evidence concerning which component is essential for success, and very little is known regarding the validity of methods or material used for the education. METHODS: Effects of standard information to heart failure patients given prior to discharge from hospital were compared with additional education by an interactive program on all-cause readmission or death within 6 months. As a secondary endpoint, patients' general knowledge of heart failure and its treatment was tested after 2 months. RESULTS: Two hundred and thirty patients were randomised to standard information (S) or additional CD-ROM education (E). In (S) 52 % reached the endpoint vs. 49 % in (E). This difference was not significant. Of those who completed the questionnaire (37 %), patients in (E) achieved better knowledge and a marginally better outcome. CONCLUSION: The lack of effect on the readmission rate could be due to an insufficient sample size but might also indicate that in pharmacologically well-treated patients there is little room for altering the course of the condition. As there was some indication that patients who knew more about their condition might fare better, the place for intensive education and support of heart failure patients has yet to be determined

Feasibility of a controlled trial aiming to prevent excessive pregnancy-related weight gain in primary health care

<p>Abstract</p> <p>Background</p> <p>Excessive gestational weight gain and postpartum weight retention may predispose women to long-term overweight and other health problems. Intervention studies aiming at preventing excessive pregnancy-related weight gain are needed. The feasibility of implementing such a study protocol in primary health care setting was evaluated in this pilot study.</p> <p>Methods</p> <p>A non-randomized controlled trial was conducted in three intervention and three control maternity and child health clinics in primary health care in Finland. Altogether, 132 pregnant and 92 postpartum women and 23 public health nurses (PHN) participated in the study. The intervention consisted of individual counselling on physical activity and diet at five routine visits to a PHN and of an option for supervised group exercise until 37 weeks' gestation or ten months postpartum. The control clinics continued their usual care. The components of the feasibility evaluation were 1) recruitment and participation, 2) completion of data collection, 3) realization of the intervention and 4) the public health nurses' experiences.</p> <p>Results</p> <p>1) The recruitment rate was slower than expected and the recruitment period had to be prolonged from the initially planned three months to six months. The average participation rate of eligible women at study enrolment was 77% and the drop-out rate 15%. 2) In total, 99% of the data on weight, physical activity and diet and 96% of the blood samples were obtained. 3) In the intervention clinics, 98% of the counselling sessions were realized, their contents and average durations were as intended, 87% of participants regularly completed the weekly records for physical activity and diet, and the average participation percentage in the group exercise sessions was 45%. 4) The PHNs regarded the extra training as a major advantage and the high additional workload as a disadvantage of the study.</p> <p>Conclusion</p> <p>The study protocol was mostly feasible to implement, which encourages conducting large trials in comparable settings.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN21512277</p

Mycobacterium tuberculosis Rv3802c Encodes a Phospholipase/Thioesterase and Is Inhibited by the Antimycobacterial Agent Tetrahydrolipstatin

The cell wall of M. tuberculosis is central to its success as a pathogen. Mycolic acids are key components of this cell wall. The genes involved in joining the α and mero mycolates are located in a cluster, beginning with Rv3799c and extending at least until Rv3804c. The role of each enzyme encoded by these five genes is fairly well understood, except for Rv3802c. Rv3802 is one of seven putative cutinases encoded by the genome of M. tuberculosis. In phytopathogens, cutinases hydrolyze the waxy layer of plants, cutin. In a strictly mammalian pathogen, such as M. tuberculosis, it is likely that these proteins perform a different function. Of the seven, we chose to focus on Rv3802c because of its location in a mycolic acid synthesis gene cluster, its putative essentiality, its ubiquitous presence in actinomycetes, and its conservation in the minimal genome of Mycobacterium leprae. We expressed Rv3802 in Escherichia coli and purified the enzymatically active form. We probed its activities and inhibitors characterizing those relevant to its possible role in mycolic acid biosynthesis. In addition to its reported phospholipase A activity, Rv3802 has significant thioesterase activity, and it is inhibited by tetrahydrolipstatin (THL). THL is a described anti-tuberculous compound with an unknown mechanism, but it reportedly targets cell wall synthesis. Taken together, these data circumstantially support a role for Rv3802 in mycolic acid synthesis and, as the cell wall is integral to M. tuberculosis pathogenesis, identification of a novel cell wall enzyme and its inhibition has therapeutic and diagnostic implications

Design of the New Life(style) study: a randomised controlled trial to optimise maternal weight development during pregnancy. [ISRCTN85313483]

BACKGROUND: Preventing excessive weight gain during pregnancy is potentially important in the prevention of overweight and obesity among women of childbearing age. However, few intervention studies aiming at weight management during pregnancy have been performed and most of these interventions were not as successful as expected. In this paper the design of the New Life(style) study is described as well as the content of the individually tailored intervention program, which focuses on controlling weight development during pregnancy. METHODS: The effectiveness of the New Life(style) intervention program versus usual care by midwives is evaluated in a randomised controlled trial. Women who expect their first child and visit one of the participating midwifery practices are included. The intervention is standardised in a protocol and executed by trained counsellors with the women who are randomised in the intervention group. During 5 sessions – at 18, 22, 30 and 36 weeks of pregnancy and at 8 weeks postpartum – individual weight gain is discussed in relation to weight gain guidelines for pregnant women of the American Institute of Medicine. Counsellors coach the women to maintain or optimise a healthy lifestyle, in a period of drastic physical and mental changes. Data is collected at 15, 25, 35 weeks of pregnancy and at 6, 26, and 52 weeks after delivery. Primary outcome measures are body weight, BMI, and skinfold thickness. Secondary outcome measures include physical activity, nutrition and blood levels of factors that are associated with energy homeostasis. DISCUSSION: Results of the current RCT will improve the knowledge of determinants of weight gain during pregnancy, weight retention after childbirth and of the effectiveness of the intervention program that is described. Caregivers and researchers in the field of health promotion are offered more insight in specific elements of the New Life(style) intervention program

Multiphase phenomena in Diesel fuel injection systems

Fuel Injection Equipment (FIE) are an integral component of modern Internal Combustion Engines (ICE), since they play a crucial role in the fuel atomization process and in the formation of a fuel/air combustible mixture, consequently affecting efficiency and pollutant formation. Advancements and improvements of FIE systems are determined by the complexity of the physical mechanisms taking place; the spatial scales are in the order of millimetres, flow may become locally highly supersonic, leading to very small temporal scales of microseconds or less. The operation of these devices is highly unsteady, involving moving geometries such as needle valves. Additionally, extreme pressure changes imply that many assumptions of traditional fluid mechanics, such as incompressibility, are no longer valid. Furthermore, the description of the fuel properties becomes an issue, since fuel databases are scarce or limited to pure components, whereas actual fuels are commonly hydrocarbon mixtures. Last but not least, complicated phenomena such as phase change or transition from subcritical to transcritical/supercritical state of matter further pose complications in the understanding of the operation of these devices