Spacecraft ram glow and surface temperature

Space shuttle glow intensity measurements show large differences when the data from different missions are compared. In particular, on the 41-G mission the space shuttle ram glow was observed to display an unusually low intensity. Subsequent investigation of this measurement and earlier measurements suggest that there was a significant difference in temperature of the glow producing ram surfaces. The highly insulating properties coupled with the high emissivity of the shuttle tile results in surfaces that cool quickly when exposed to deep space on the night side of the orbit. The increased glow intensity is consistent with the hypothesis that the glow is emitted from excited NO2. The excited NO2 is likely formed through three body recombination (OI + NO + M = NO2*) where ramming of OI interacts with weakly surface bound NO. The NO is formed from atmospheric OI and NI which is scavenged by the spacecraft moving through the atmosphere. It is postulated that the colder surfaces retain a thicker layer of NO thereby increasing the probability of the reaction. It has been found from the glow intensity/temperature data that the bond energy of the surface bound precursor, leading to the chemical recombination producing the glow, is approximately 0.14 eV. A thermal analysis of material samples of STS-8 was made and the postulated temperature change of individual material samples prior to the time of glow measurements above respective samples are consistent with the thermal effect on glow found for the orbiter surface

SETTING STANDARDS FOR SUSTAINABLE TOURISM, AS A SOURCES OF ENTREPRENEURSHIP

Abstract. Tourism is no doubt one of the largest industries and sources of entrepreneurship in the world.Behind fuels, chemicals and automotive parts, it is fourth in the amount of export income it generates.Over the recent decades, a plethora of tourism certification programs have sprung up worldwide in an effort to recognize tourism businesses who truly work to reduce negative impacts by using sustainable practices. This worldwide proliferation of tourism certification programs, however, has led to consumer confusion, lack of brand recognition and widely varying standards. Here the best practice standards for tourism certification programs is used as laid out in the Mohonk Agreement, and the recently released Global Sustainable Tourism Criteria, envisioned to serve as the common set of baseline criteria by which to accredit certification programs, to evaluate four state-level tourism certification programs as case studies in the world. This paper also conjecture what the future may look like for these programs. At the end some notes have been proposed for more researches in the way of tourism standardization

Open-Ended Modeling Group Projects in Introductory Statics and Dynamics Courses

Traditionally, the types of problems that students see in their introductory statics and dynamics courses are well-structured textbook problems with a single solution [1]. These types of questions are often seen by students as being somewhat at-odds with the more “realistic” challenges that they may face in their design or lab courses. Additionally, in the pandemic-necessitated paradigm of emergency online instruction, methods of assessment beyond traditional exams have become more emphasized, both as a way of keeping students engaged by giving the material relevance and of ensuring that the work that they present is their own when so many solutions are available online

A Rationale for Coastal Wetland Restoration through Spoil Bank Management in Louisiana, USA

The rationale and outline of an implementation plan for restoring coastal wetlands in Louisiana is presented. The rationale for the plan is based on reversing the consequences of documented cause-and-effect relationships between wetland loss and hydrologic change. The main feature is to modify the extensive interlocking network of dredged spoil deposits, or spoil banks, by reestablishing a more natural water flow at moderate flow velocity (/sec). Guidelines for site selection from thousands of potential sites are proposed. Examples of suitable sites are given for intermediate marshes. These sites exhibit rapid deterioration following partial or complete hydrologic impoundment, implying a strong hydrologic, rather than sedimentological, cause of wetland deterioration. We used an exploratory hydrologic model to guide determination of the amount of spoil bank to be removed. The results from an economic model indicated a very effective cost-benefit ratio. Both models and practical experience with other types of restoration plans, in Louisiana and elsewhere, exhibit an economy of scale, wherein larger projects are more cost effective than smaller projects. However, in contrast to these other projects, spoil bank management may be 100 to 1000 times more cost effective and useful in wetland tractssites

Deficits in Beam-Walking After Neonatal Motor Cortical Lesions are not Spared by Fetal Cortical Transplants in Rats

Adult rats that sustained unilateral motor cortical lesions at birth demonstrated deficits in traversing an elevated narrow beam. These deficits, manifested by hindlimb slips off the edge of the beam, were not spared in animals that received fetal cortical transplants into the lesion cavity immediately after lesion placement

Phosphorus Concentrations Into A Subtropical Lake Strongly Influence Nitrogen Accumulation, Nitrogen Export, And Chl A Concentrations

We measured water quality monthly for 22 years in water entering, within, and exiting a 65 km(2) shallow polymictic and eutrophic freshwater lake in the northern Gulf of Mexico. Fertilizer use in the watershed is the dominate source of phosphorous (P) going into the lake and controls the lake\u27s P concentrations, but nitrogen (N) fertilizer use was not related to total nitrogen concentration in the lake. Half of the particulate P entering the lake is trapped within it and there is a net accumulation of N that appears to be from the stimulation of nitrogen fixation. The lake\u27s concentration of Chlorophyll a (mu g Chl a l(-1)) and increase in N in the lake was directly related to the concentration of P in water entering the lake. Variations in the Chl a concentration within a freshwater lake downstream are also directly related to the annual use of P fertilizer, but not to N fertilizer use. Reducing agriculture-sourced P runoff will lower (but not eliminate) both the frequency of algal blooms within Lac des Allemands and the amount of N delivered to the estuary

Electron Density and Electron Neutral Collision Frequency in the Ionosphere Using Plasma Impedance Probe Measurement

Swept Impedance Probe measurements in a sporadic E layer observed during the Sudden Atomic Layer (SAL) sounding rocket mission are analyzed to obtain absolute electron densities and electron neutral collision frequencies accurately. Three sets of upleg and downleg impedance data are selected for the analysis. Initial estimates of the plasma parameters are obtained through a least mean square fit of the measured impedance data against the analytical impedance formula ZB(f ) of Balmain (1969). These initial parameters are used as a starting point to drive a finite difference computational model of an antenna immersed in a plasma called PF-FDTD. The parameters are then tuned until a close fit is obtained between the measured impedance data and the numerical impedance data calculated by the PF-FDTD simulation. The electron densities obtained from the simulation were close to those obtained from the IRI 2001 model. The electron neutral collision frequencies obtained from the more accurate PF-FDTD simulation were up to 20% lower than the values predicted by Balmain’s formula. The obtained collision frequencies are also lower than the quiet time values predicted by Schunk and Nagy (2000) when used in conjunction with neutral densities and electron temperature from the Mass Spectrometer Incoherent Scatter Radar Extended-90 model

Interaction of intermediate energy protons with light nuclei

Interaction of intermediate energy protons with light nucle

Hurricane Signals In Salt Marsh Sediments: Inorganic Sources And Soil Volume

The inorganic content of 51 dated sediment cores from Mississippi River deltaic plain salt marsh wetlands peaks with the landfall of hurricanes. Variations in the inorganic sediment content demonstrate no temporal coherence with changes in either the Mississippi River suspended matter concentration or discharge, or with wetland losses on this coast. The inorganic matter brought to wetlands during hurricanes is sufficient to account for the accumulated inorganic sediment, and the volume averages 9% of the soil volume. A sediment deficit\u27\u27 hypothesis, which makes a causal connection between a changing inorganic supply and the dramatically high wetland losses on this coast, is therefore rejected. Our results support the hypothesis that wetlands of an undeveloped coast receive the majority of their inorganic sediments from offshore and not from overbank flooding or through crevasses. Restoration and wetland maintenance (prevention) goals should be implemented with this in mind: the coastal wetland losses of the last century along this coast appear to be a consequence of the diminished accumulation of organic matter and not from variations in inorganic sediment loading