Ring particle sizes and composition derived from eclipse cooling curves and reflection spectra

The probable chemistry of the Saturn rings is reviewed. Reflectance spectra for H20 and NH3 frosts and Saturn's rings are compared, along with temperature dependence of 1.6 microns water frost feature. The reflection spectra of Galilean satellite J2 and water frost are also reviewed

Spacecraft instrumentation and observations for the spectral reflectance experiment of Martian frost Final report, 1 Oct. 1968 - 31 Mar. 1970

Instrumentation to determine spectral reflectance properties for simulated Martian frost

Navigating the Middle Grades and Preparing Students for High School Graduation

This brief presents preliminary findings from an exploratory study of New York City students' transitions into, through, and out of the middle grades. Our analysis reveals that students' attendance and achievement in their early schooling (fourth grade) predict whether students are likely to graduate from high school many years later. Further, we find that many students begin the middle grades on-track to graduate high school but fall off this trajectory before the end of eighth grade. These findings suggest that teachers and administrators should pay close attention to students whose attendance and math achievement fall during the middle grades, as these students are particularly at risk for not graduating from high school on time

Automatic control study of the icing research tunnel refrigeration system

The Icing Research Tunnel (IRT) at the NASA Lewis Research Center is a subsonic, closed-return atmospheric tunnel. The tunnel includes a heat exchanger and a refrigeration plant to achieve the desired air temperature and a spray system to generate the type of icing conditions that would be encountered by aircraft. At the present time, the tunnel air temperature is controlled by manual adjustment of freon refrigerant flow control valves. An upgrade of this facility calls for these control valves to be adjusted by an automatic controller. The digital computer simulation of the IRT refrigeration plant and the automatic controller that was used in the simulation are discussed

Comet thermal modeling

The past year was one of tremendous activity because of the appearance of Halley's Comet. Observations of the comet were collected from a number of sources and compared with the detailed predictions of the comet thermal modeling program. Spacecraft observations of key physical parameters for cometary nucleus were incorporated into the thermal model and new cases run. These results have led to a much better understanding of physical processes on the nucleus and have pointed the way for further improvements to the modeling program. A model for the large-scale structure of cometary nuclei was proposed in which comets were envisioned as loosely bound agglomerations of smaller icy planetesimals, essentially a rubble pile of primordial dirty snowballs. In addition, a study of the physical history of comets was begun, concentrating on processes during formation and in the Oort cloud which would alter the volatile and nonvolatile materials in cometary nuclei from their pristine state before formation

Rest, Does the Drive for Efficiency Really Lead to Sufficiency?

Messiah College faculty scholarship papers : submitted by faculty in partial fulfillment of the requirements for promotion to the rank of professo

Navigating the Middle Grades: Evidence from New York City

Educators have long asserted that the middle grade years (typically, grades six through eight) are a time of both great importance and vulnerability in students' K-12 schooling. Anecdotal and empirical evidence suggest that students encounter new social and emotional challenges, increased academic demands, and major developmental transitions during the middle grade years. In this study, we investigate whether and how students' achievement and attendance change between grade four and eight and identified moments during this period when students' achievement and attendance suggest that they will struggle to graduate from high school within four years

The direct synthesis of crosslinked polymeric azomethines

Char yields of synthesized crosslinked polymeric azomethine