Manned Mars mission vehicle design requirements for aerocapture

Vehicle design requirements of a reusable system for manned Mars missions which employ aerocapturing techniques to obtain desired orbital velocities are defined. Requirements for vehicle L/D and ballistic coefficient are determined for expected aerocapture velocities. Conclusions are presented concerning g-loads environment and TPS requirements for a vehicle that aerocaptures at Mars and Earth. Although the goal of a reusable system (based on current state-of-art technologies) was not obtained, the viability of aerocapture at Mars and Earth was established

Race, Class, And Gender In Boys\u27 Education: Repositioning Intersectionality Theory

Boys\u27 identities are distinctly gendered, racialized, and classed across disparate social and cultural contexts. Related intersectional identity processes are associated with boys\u27 academic success. While intersectionality has been utilized throughout boys\u27 education scholarship, a limited, light touch approach is often enacted. As a critical logic of interpretation, intersectionality theory accounts for race, class, and gender within equity-based empirical studies. The authors contend insufficient engagement with intersectionality may lead educational research on boys\u27 social and learner identities to become static. Examining boys\u27 identities through intersectional approaches reveals more complex insights particularly related to their school engagement. Critical of the recent boy crisis literature, this article strives to compel theorists of boys\u27 education to more fully leverage the history, constructs, and epistemologies of intersectionality

Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation

Ammonia production by Klebsiella pneumoniae is not economical with present strains and improving nitrogen fixation to its theoretical limits in this organism is not sufficient to achieve economic viability. Because the value of both the hydrogen produced by this organism and the methane value of the carbon source required greatly exceed the value of the ammonia formed, ammonia (fixed nitrogen) should be considered the by-product. The production of hydrogen by KLEBSIELLA or other anaerobic nitrogen fixers should receive additional study, because the activity of nitrogenase offers a significant improvement in hydrogen production. The production of fixed nitrogen in the form of cell mass by Azotobacter is also uneconomical and the methane value of the carbon substrate exceeds the value of the nitrogen fixed. Parametric studies indicate that as efficiencies approach the theoretical limits the economics may become competitive. The use of nif-derepressed microorganisms, particularly blue-green algae, may have significant potential for in situ fertilization in the environment

On the Interface Between Operations and Human Resources Management

Operations management (OM) and human resources management (HRM) have historically been very separate fields. In practice, operations managers and human resource managers interact primarily on administrative issues regarding payroll and other matters. In academia, the two subjects are studied by separate communities of scholars publishing in disjoint sets of journals, drawing on mostly separate disciplinary foundations. Yet, operations and human resources are intimately related at a fundamental level. Operations are the context that often explains or moderates the effects of human resource activities such as pay, training, communications and staffing. Human responses to operations management systems often explain variations or anomalies that would otherwise be treated as randomness or error variance in traditional operations research models. In this paper, we probe the interface between operations and human resources by examining how human considerations affect classical OM results and how operational considerations affect classical HRM results. We then propose a unifying framework for identifying new research opportunities at the intersection of the two fields

Improvements in Health Conditions in Galveston School System From 1934-1936

Since health supervision is now recognized as a most important part of the school and community health program, we cannot well separate public health in a school system from public health in the community. There are fundamental reasons why a community should be responsible for the conservation of the health of the children in its schools. Doctor Hiscock, in his book entitled Public Health Organizations , argues thus: Children required to attend school must be protected against neglect, ignorance or indifference on the part of parents of some children who are permitted to attend school while in the communicable stages of disease. When a community makes education compulsory, it must assume responsibility for providing healthful environment for the children. It is important to educate the child in the principles of healthful living, so that he may himself have sound health and thus safeguard the community in the future. Furthermore, it is essential to find out and endeavor to have corrected physical and mental defects in the child before they affect his ability to learn and interfere with his school career . Dr. Hiscock suggests five primary purposes of school health supervision: 1. To detect and prevent the spread of communicable disease. 2. To insure sanitary conditions at the school plant. 3. To discover early and guide the child to appreciate the care for correction of physical and mental defects. 4. To promote sound physical development. 5. To educate the child in matters of community and personal hygiene and in the principles of healthy living .1 The major functions of a school health program are to carry out the purposes as outlined. They may well he divided into four groups: 1. Sanitation; 2. Medical and Nursing Service; 3. Health Education; and 4. Physical Education. Every school situation, however casual or minor it may be, is an opportunity for health education. And every adult member of the school staff has some responsibility. 1 The American Association of School Physicians. School Physicians Bulletin. Pages 3-4. Volume VI. January, 1936

A Multiwavelength Investigation of Unidentified EGRET Sources

Statistical studies indicate that the 271 point sources of high-energy gamma rays belong to two groups: a Galactic population and an isotropic extragalactic population. Many unidentified extragalactic sources are certainly blazars, and it is the intention of this work to uncover gamma-ray blazars missed by previous attempts. Until recently, searches for blazar counterparts to unidentified EGRET sources have focused on finding AGN that have 5-GHz radio flux densities S_5 near or above 1 Jy. However, the recent blazar identification of 3EG J2006-2321 (S_5 = 260 mJy) and other work suggest that careful studies of weaker flat-spectrum sources may be fruitful. In this spirit, error circles of 4 high-latitude unidentified EGRET sources have been searched for 5-GHz sources. The gamma-ray sources are 3EG J1133+0033, 3EG J1212+2304, 3EG J1222+2315, and 3EG J1227+4302. Within the error contours of each of the four sources are found 6 radio candidates; by observing the positions of the radio sources with the 0.81-m Tenagra II telescope it is determined that 14 of these 24 radio sources have optical counterparts with R < 22. Eight of these from two different EGRET sources have been observed in the B, V, and R bands in more than one epoch and the analysis of these data is ongoing. Any sources that are found to be variable will be the objects of multi-epoch polarimetry studies.Comment: 6 pages, 2 tables. To appear in Astrophysics & Space Scienc