Helical coaxial resonator RF filter

Helical coaxial resonator RF filte

An Investigation into the Suitability of Sulfate-Reducing Bacteria as Models for Martian Forward Contamination

The NASA Planetary Protection policy requires interplanetary space missions do not compromise the target body for a current or future scientific investigation and do not pose an unacceptable risk to Earth, including biologic materials. Robotic missions to Mars pose a risk to planetary protection in the forms of forward and reverse contamination. To reduce these risks, a firm understanding of microbial response to Mars conditions is required. Sulfate-reducing bacteria are prime candidates for potential forward contamination on Mars. Understanding the potential for forward-contamination of sulfate-reducers on Mars calls for the characterization of sulfate-reducers under Mars atmosphere, temperature, and sulfate-brines. This study investigated the response of several sulfate-reducing bacteria, including spore formers and psychrophiles. The psychrophile Desulfotalea psychrophila was found to inconsistently survive positive control lab conditions, attributed to an issue shipping pure cultures. Desulfotomaculum arcticum, a spore-forming mesophilic sulfate-reducer, and Desulfuromusa ferrireducens, an iron and sulfate-reducer, were metabolically active under positive control lab conditions with complex and minimal growth medium. A wastewater treatment sulfate-reducing bacteria (SRB) isolate was subjected to sulfate + growth-medium solutions of varied concentrations (0.44 & 0.55% wt. SO42-). The wastewater SRB displayed higher cellular light-absorbance levels at delayed rates in 0.55% sulfate solutions, suggesting a greater total culture reproduction, but with increased lag time. Additional SRB were isolated from marine sediments, subjected to a shock pressure of 8.73 GPa, and returned to ideal conditions. The sulfate-concentration patterns in the impacted SRB culture suggests a destruction of culture occurred somewhere during the preparation process. The response of SRB in this investigation to Ca and Na sulfate-brines suggests that Martian sulfate deposits offer a viable energy sink to terrestrial microorganisms, and the studied SRB are capable of replication at reduced water-activity. Further investigation (i.e. sulfate cations and concentrations, temperature, pressure, etc.) may identify Martian locations at risk to forward contamination

Process of casting heavy slips Patent

Freeze casting of metal ceramic and refractory compound powders into plastic slip

Continuing Conflict

A relatively small but growing literature in economics examines conflictive activities where agents allocate their resource endowments between wealth production and appropriation. To date, their studies have employed a one period, static game theoretic framework. We propose a methodology to extend this literature to a dynamic setting, modeling continuous conflict over renewable natural resources between two rival groups. Investigating the system’s steady states and dynamics, we find two results of general interest. First, Hirshleifer’s “paradox of power” is self-correcting. Second, if productive activities cause damage to disputed resources, the introduction of a small amount of conflictive activity enhances social welfare.Conflict, Dynamics, Paradox of Power, Renewable Resources

A SELF-REFLECTIVE INVERSE DEMAND SYSTEM

This paper introduces an inverse differential demand system that has exactly the same form as the corresponding direct version. Its application is illustrated with the case of Australian fruit, whose prices were substantially affected by Severe Tropical Cyclone Larry in 2006.

Conflict and Renewable Resources

The economic literature on conflict employs a static game theoretic frame- work developed by Jack Hirshleifer. We extend this literature by explicitly introducing conflict dynamics into the model. Our specific application is based on two stylized facts. First, conflict often arises over scarce renew- able resources, and second those resources often lack well-defined and/or enforceable property rights. Our stylized model features two rival groups, each dependent on a single contested renewable resource. Each period, the groups allocate their members between resource harvesting and resource appropriation (or conflict) in order to maximize their income. This leads to a complex non-linear dynamic interaction between conflict, the two populations, and the resource. The system's steady states are identified and comparative statics are computed. As developed, the model relates most closely to conflict over renewable resources in primitive societies. The system's global dynamics are investigated in simulations calibrated for the historical society of Easter Island. The model's implications for contemporary lesser developed societies are examined.Conflict, Dynamics, Renewable Resources

Corporate Social Responsibility and the Environment: A Theoretical Perspective

We survey the growing theoretical literature on the motives for and welfare effects of corporate greening. We show how both market and political forces are making environmental CSR profitable, and we also discuss morally-motivated or altruistic CSR. Welfare effects of CSR are subtle and situation-contingent, and there is no guarantee that CSR enhances social welfare. We identify numerous areas in which additional theoretical work is needed.corporate social responsibility, environment, self-regulation, preemption, private politics

X-29A technology demonstrator flight test program overview

An overview of the X-29A functional flight program and concept evaluation program is presented, including some of the unique and different preparations for the first flight. Included are a discussion of the many organizational responsibilities and a description of the program management structure for the test team. Also discussed are preflight ground, flight functional envelope expansion, and flight research test objectives and qualitive results to date for both a limited-envelope flight control system and an expanded-envelope system. The aircraft, including the instrumentation system and measurements, is described. In addition, a discussion is included regarding the use of major support facilities, such as ground and flight simulators, the NASA Western Aeronautical Test Range and mission control center, and the Grumman automated telemetry station. An overview of the associated real-time and postflight batch data processing software approaches is presented. The use of hardware-in-the-loop simulation for independent verification and validation and mission planning and practice is discussed. Also included is a description of the flight-readiness review, the airworthiness and flight safety review, work scheduling, technical briefings, and preflight and postflight crew briefings. The configuration control process used on the X-29A program is described, and its relationship to both simulation and aircraft operations is discussed. An X-29A schedule overview is presented with an outline of a proposed follow-on program

Environmental Inspection Proclivity and State Manufacturing Growth: The US Experience from the 1990s

In this paper we construct a ranking of states based on their proclivity to inspect facilities for environmental compliance. Our measure utilizes state-level inspections data supplied by the US Environmental Protection Agency. After developing our ranking, we use it to predict state-level growth in manufacturing establishments. In doing so, we find support for the notion that enforcement intensity adversely impacts such growth. Our results offer insight into why existing studies that examine the impact of environmental regulation on location and growth produce inconsistent results.Monitoring and Enforcement, Environmental Regulations, Business Formation Growth

Astroturf: Interest Group Lobbying and Corporate Strategy

We study three corporate nonmarket strategies designed to influence the lobbying behavior of other special interest groups: (1) astroturf, in which the firm covertly subsidizes a group with similiar views to lobby when it normally would not; (2) the bear hug, in which the firm overtly pays a group to alter its lobbying activitives; and (3) self-regulation, in which the firm voluntarily limits the potential social harm from its activities. All three strategies reduce the informativeness of lobbying, and all reduce the payoff of the public decision-maker. We show that the decision-maker would benefit by requiring the public disclosure of funds but that the availability of alternative strategies limits the impact of such a policy.