Liquid-fuel valve with precise throttling control

Prototype liquid-fuel valve performs on-off and throttling functions in vacuum without component cold-welding or excessive leakage. Valve design enables simple and rapid disassembly and parts replacement and operates with short working stroke, providing maximum throttling sensitivity commensurate with good control

Comparison of dermal and inhalation routes of entry for organic chemicals

The quantitative comparison of the chemical concentration inside the body as the result of a dermal exposure versus an inhalation exposure is useful for assessing human health risks and deciding on an appropriate protective posture. In order to describe the relationship between dermal and inhalation routes of exposure, a variety of organic chemicals were evaluated. The types of chemicals chosen for the study were halogenated hydrocarbons, aromatic compounds, non-polar hydrocarbons and inhalation anesthetics. Both dermal and inhalation exposures were conducted in rats and the chemicals were in the form of vapors. Prior to the dermal exposure, rat fur was closely clipped and during the exposure rats were provided fresh breathing air through latex masks. Blood samples were taken during 4-hour exposures and analyzed for the chemical of interest. A physiologically based pharmacokinetic model was used to predict permeability constants (cm/hr) consistent with the observed blood concentrations of the chemical. The ratio of dermal exposure to inhalation exposure required to achieve the same internal dose of chemical was calculated for each test chemical. The calculated ratio in humans ranged from 18 for styrene to 1180 for isoflurane. This methodology can be used to estimate the dermal exposure required to reach the internal dose achieved by a specific inhalation exposure. Such extrapolation is important since allowable exposure standards are often set for inhalation exposures, but occupational exposures may be dermal

Potassium-specific ion-exchanger microelectrodes to measure K + activity in the renal distal tubule.

The recent introduction of miniature liquid ion-exchanger electrodes provides the possibility of overcoming previously encountered limitations on the measure-ment of specific ionic activities in biological fluids. Hydrogen ion and sodium ion activities have been stuccessfully determined by means of glass-membrane electrodes(l-5). However, in the presence of sodium, glass electrodes are usually inadequate for measuring potassium, divalent cation or anion activities(4). The adaptation of the liquid ion-exchanger principle for use with microelectrodes, permits measurement of K+ and Cl- activities on botlh sides of the cell mem-brane(6-8). We hlave constructed potassium-selective liquid ion-exchanger microelectrodes to measure K+ activity in rat distal tubules. Because this technique is still in a relatively early stage of development, it may be useful to review some details of the theoretical basis for the method and some of the practical considerations rele-vant to its application. Our experience has been with K+ ion-exchanger elec-trodes but the same teclhniques apply to anion-sensitive electrodes. Liquid ion exchangers are solutions in an organic solvent of a charged organic compound(9). Such ion-exchanger solutions were originally developed for indus-trial purposes; in the early 1960's they were increasingly studied as model mem-brane systems lhaving many of the properties of carrier-medicated ion permea-tion(9-11). A Ca selective macroelectrode was described by Ross(12), an

LAND TITLE TRANSFER: A REGRESSION

Land is the basic asset of society. Its ownership affords the security upon which our complex credit structure rests. Certainty as to ownership is essential to the continued peace of each landowner or farm owner. So Professor Powell grounds his study of land title registration— the Torrens system —deep in concern for the public welfare. He\u27 could have grounded it deeper. Today our accepted social goals include something more than peace. Public opinion is mobilizing behind maximum utilization for the benefit of all classes. Our governments—federal, state, and municipal—are committed to a program of reconstructing our cities and rehousing at least a third of the nation. Humanitarian sentiment, in the guise inter alia of land-purchase programs, has even begun to extend to the pitifully insecure one-half of our farm population. City planning, rural rehabilitation, metropolitan communities, and garden cities; public subsidies, government financing, graded-tax plans, zoning, and eminent domain—all these are in the headlines and in the air. It takes no prophet to foresee that fundamental reforms in land utilization are hot upon us. Yet for the achievement of such reforms without payment of undue and continued tribute to private monopolies and without fruitless bother and delay—perhaps even if they are to be achieved at all—major changes must be effected in our antiquated, pre-commerce system of land transfer. Cheap, expeditious, and secure methods must be designed, if they are not already available, to replace the present complicated and dilatory methods which, while costly to the individual and burdensome to the public, afford no adequate security of title. Streamlined need cannot long endure horse-and-buggy obstacles to the liquidity of land. It is an ancient query, but its relevance grows: why should not a lot or a farm be as easily acquired and as securely held as a ship or a share of stock or an automobile

Air Force F-16 Aircraft Engine Aerosol Emissions Under Cruise Altitude Conditions

Selected results from the June 1997 Third Subsonic Assessment Near-Field Interactions Flight (SNIF-III) Experiment are documented. The primary objectives of the SNIF-III experiment were to determine the partitioning and abundance of sulfur species and to examine the formation and growth of aerosol particles in the exhaust of F-16 aircraft as a function of atmospheric and aircraft operating conditions and fuel sulfur concentration. This information is, in turn, being used to address questions regarding the fate of aircraft fuel sulfur impurities and to evaluate the potential of their oxidation products to perturb aerosol concentrations and surface areas in the upper troposphere. SNIF-III included participation of the Vermont and New Jersey Air National Guard F-16's as source aircraft and the Wallops Flight Facility T-39 Sabreliner as the sampling platform. F-16's were chosen as a source aircraft because they are powered by the modern F-100 Series 220 engine which is projected to be representative of future commercial aircraft engine technology. The T-39 instrument suite included sensors for measuring volatile and non-volatile condensation nuclei (CN), aerosol size distributions over the range from 0.1 to 3.0 (micro)m, 3-D winds, temperature, dewpoint, carbon dioxide (CO2), sulfur dioxide (SO2), sulfuric acid (H2SO4), and nitric acid (HNO3)

The Prescribing Function in World Constitutive Process: How International Law is Made

No problem has proved more refractory to lawyers and scholars than understanding and explaining how international law is made. Domestic analogues, whose explanatory power may be inadequate even in their own contexts, have so little relevance to the complexities of international politics that those who invoke them finish either by throwing up their hands and conceding that the model is inappropriate for the taskl or by painting themselves into the palpably absurd position that there is no international law. But, of course, there are many effective international norms. To gainsay such norms because of a theory is a grotesque caricature of understanding and scholarship. As the world becomes more pervasively transnational and interdependent, an understanding of how international law is made and, even more to the point, of how to make it, becomes a matter of greatest practical urgency. In any community how law is made immensely affects the shaping and sharing of all values