1,388 research outputs found
English Language Learners and Standardized Tests
A surge in limited English proficiency (LEP) enrollment became a nationwide phenomenon between 1995 and 2005, as virtually all regions of the country experienced a rapid growth in immigrant population. In Buffalo, the increase in ELL students stemmed largely from the active resettlement of refugees from around the world in Buffalo. In 2004-2005, Buffalo had 2,539 LEP students who collectively spoke 46 different languages. In 2009-2010, that enrollment number shot up to 3,481 students, who spoke 67 languages. In Buffalo, as in many locales, the rise in ELL learners has coincided with a dramatic increase in high stakes standardized testing; unfair testing policies being employed have often failed to reflect the realities of English language learning
Modified McLeod gage records automatically
Modified Mc Leod gage records pressure measurements automatically. The measurements can be programmed in advance by means of an automatic timer
Automatic recording McLeod gauge Patent
Automatic recording McLeod gage with three electrodes and solenoid valve connectio
An investigation of near critical and super- critical burning of fuel droplets Annual report, 1 Sep. 1967 - 1 Sep. 1968
Near critical and supercritical burning of fuel droplet
Priorities for Microgravity Combustion Research and Goals for Workshop Discussions
Several concerns motivate fundamental research: combustion-generated pollutants are re-emerging as a major problem, new combustion technologies are needed for effective energy utilization, municipal and hazardous waste incineration are needed to replace landfills and storage, new combustion technologies are needed for advanced aircraft and spacecraft propulsion systems, and current understanding of fires and explosion hazards is limited - particularly for space-craft environments. Thus, it is of interest to determine how experimentation using microgravity facilities can advance research relevant to these problems
An investigation of air solubility in Jet A fuel at high pressures
Problems concerned with the supercritical injection concept are discussed. Supercritical injection involves dissolving air into a fuel prior to injection. A similar effect is obtained by preheating the fuel so that a portion of the fuel flashes when its pressure is reduced. Flashing improves atomization properties and the presence of air in the primary zone of a spray flame reduces the formation of pollutants. The investigation is divided into three phases: (1) measure the solubility and density properties of fuel/gas mixtures, including Jet A/air, at pressures and correlate these results using theory; (2) investigate the atomization properties of flashing liquids, including fuel/dissolved gas systems. Determine and correlate the effect of inlet properties and injector geometry on mass flow rates, Sauter mean diameter and spray angles; (3) examine the combustion properties of flashing injection in an open burner flame, considering flame shape and soot production
Space Station Freedom combustion research
Extended operations in microgravity, on board spacecraft like Space Station Freedom, provide both unusual opportunities and unusual challenges for combustion science. On the one hand, eliminating the intrusion of buoyancy provides a valuable new perspective for fundamental studies of combustion phenomena. On the other hand, however, the absence of buoyancy creates new hazards of fires and explosions that must be understood to assure safe manned space activities. These considerations - and the relevance of combustion science to problems of pollutants, energy utilization, waste incineration, power and propulsion systems, and fire and explosion hazards, among others - provide strong motivation for microgravity combustion research. The intrusion of buoyancy is a greater impediment to fundamental combustion studies than to most other areas of science. Combustion intrinsically heats gases with the resulting buoyant motion at normal gravity either preventing or vastly complicating measurements. Perversely, this limitation is most evident for fundamental laboratory experiments; few practical combustion phenomena are significantly affected by buoyancy. Thus, we have never observed the most fundamental combustion phenomena - laminar premixed and diffusion flames, heterogeneous flames of particles and surfaces, low-speed turbulent flames, etc. - without substantial buoyant disturbances. This precludes rational merging of theory, where buoyancy is of little interest, and experiments, that always are contaminated by buoyancy, which is the traditional path for developing most areas of science. The current microgravity combustion program seeks to rectify this deficiency using both ground-based and space-based facilities, with experiments involving space-based facilities including: laminar premixed flames, soot processes in laminar jet diffusion flames, structure of laminar and turbulent jet diffusion flames, solid surface combustion, one-dimensional smoldering, ignition and flame spread of liquids, drop combustion, and quenching of panicle-air flames. Unfortunately, the same features that make microgravity attractive for fundamental combustion experiments, introduce new fire and explosion hazards that have no counterpart on earth. For example, microgravity can cause broader flammability limits, novel regimes of flame spread, enhanced effects of flame radiation, slower fire detector response, and enhanced combustion upon injecting fire extinguishing agents, among others. On the other hand, spacecraft provide an opportunity to use 'fire-safe' atmospheres due to their controlled environment. Investigation of these problems is just beginning, with specific fire safety experiments supplementing the space based fundamental experiments listed earlier; thus, much remains to be done to develop an adequate technology base for fire and explosion safety considerations for spacecraft
A WATER QUALITY STRATEGY FOR THE MISSISSIPPI RIVER BASIN AND THE GULF OF MEXICO
Nutrient pollution, now the leading cause of water quality impairment in the United States, has had significant impact on the nation's waterways. Excessive nutrient pollution has been linked to habitat loss, fish kills, blooms of toxic algae, and hypoxia (oxygen depleted water). The hypoxic 'dead zone' in the Gulf of Mexico is one of the most striking illustrations of what can happen when too many nutrients from inland watersheds reach coastal areas. Despite the efforts of municipal building programs, industrial wastewater requirements and agricultural programs designed to reduce sediment loads in waterways, water quality and nutrient pollution continues to be a problem. We undertook a policy analysis to assess how the agricultural community could better reduce its contribution to the 'dead zone' and also evaluate the synergistic impacts of these policies on other environmental concerns like climate change. Using a sectoral model of U.S. agriculture, we compared policies including untargeted conservation subsidies, nutrient trading, Conservation Reserve Program extension, agricultural sales of carbon and greenhouse gas credits and fertilizer reduction. This economic and environmental analysis is watershed based, primarily focusing on nitrogen in the Mississippi River basin, allowing us to assess the distribution of nitrogen reduction in streams, environmental co-benefits and impact on agricultural cash flows within the Mississippi River basin from various options. The model incorporates natural resource accounts and alternative production practices, making it possible to get a more a complete picture of the costs and co-benefits of nutrient reduction. These elements also help to identify those policy options that minimize the costs to the farmers and maximize benefits to society.Resource /Energy Economics and Policy,
Investigation of critical burning of fuel droplets
The steady combustion characteristics of droplets were considered in combustion chamber environments at various pressures, flow conditions, and ambient oxidizer concentrations for a number of hydrocarbon fuels. Using data obtained earlier, predicted gasification rates were within + or - 30% of measurements when the correction for convection was based upon average properties between the liquid surface and the flame around the droplet. Analysis was also completed for the open loop response of monopropellant droplets, based upon earlier strand combustion results. At the limit of large droplets, where the effect of flame curvature is small, the results suggest sufficient response to provide a viable mechanism for combustion instability in the frequency and droplet size range appropriate to practical combustors. Calculations are still in progress for a broader range of droplet sizes, including conditions where active combustion effects are small
Investigation of critical burning of fuel droplets
Steady and unsteady combustion of liquid fuel droplets under rocket engine conditions was analyzed. Emphasis was placed on combustion at elevated pressures and temperatures. The results and their technical application to the design of liquid fueled rocket engines and the determination of combustion instability characteristics of these engines were summarized
- …