5,695 research outputs found
Solar thermal technology development: Estimated market size and energy cost savings. Volume 1: Executive summary
Estimated future energy cost savings associated with the development of cost-competitive solar thermal technologies (STT) are discussed. Analysis is restricted to STT in electric applications for 16 high-insolation/high-energy-price states. The fuel price scenarios and three 1990 STT system costs are considered, reflecting uncertainty over future fuel prices and STT cost projections. STT R&D is found to be unacceptably risky for private industry in the absence of federal support. Energy cost savings were projected to range from 10 billion (1990 values in 1981 dollars), dependng on the system cost and fuel price scenario. Normal R&D investment risks are accentuated because the Organization of Petroleum Exporting Countries (OPEC) cartel can artificially manipulate oil prices and undercut growth of alternative energy sources. Federal participation in STT R&D to help capture the potential benefits of developing cost-competitive STT was found to be in the national interest
New massive supergravity multiplets
We present new off-shell formulations for the massive superspin-3/2
multiplet. In the massless limit, they reduce respectively to the old minimal
(n=-1/3) and non-minimal () linearized formulations for 4D N=1
supergravity. Duality transformations, which relate the models constructed, are
derived.Comment: 18 pages, LaTeX; v2: minor changes, references adde
Time reversal and exchange symmetries of unitary gate capacities
Unitary gates are an interesting resource for quantum communication in part
because they are always invertible and are intrinsically bidirectional. This
paper explores these two symmetries: time-reversal and exchange of Alice and
Bob. We will present examples of unitary gates that exhibit dramatic
separations between forward and backward capacities (even when the back
communication is assisted by free entanglement) and between
entanglement-assisted and unassisted capacities, among many others. Along the
way, we will give a general time-reversal rule for relating the capacities of a
unitary gate and its inverse that will explain why previous attempts at finding
asymmetric capacities failed. Finally, we will see how the ability to erase
quantum information and destroy entanglement can be a valuable resource for
quantum communication.Comment: 17 pages. v2: improved bounds, clarified proofs. v3: published
version, added section explaining notatio
Method for fiberizing ceramic materials Patent
Process for fiberizing ceramic materials with high fusion temperatures and tensile strengt
D=2 N=(2,2) Semi Chiral Vector Multiplet
We describe a new 1+1 dimensional N=(2,2) vector multiplet that naturally
couples to semi chiral superfields in the sense that the gauged supercovariant
derivative algebra is only consistent with imposing covariantly semi chiral
superfield constraints. It has the advantages that its prepotentials shift by
semi chiral superfields under gauge transformations. We also see that the
multiplet relates the chiral vector multiplet with the twisted chiral vector
multiplet by reducing to either multiplet under appropriate limits without
being reducible in terms of the chiral and twisted chiral vector multiplet.
This is explained from the superspace geometrical point of view as the result
of possessing a symmetry under the discrete supercoordinate transformation that
is responsible for mirror copies of supermultiplets. We then describe how to
gauge a non linear sigma model with semi chiral superfields using the
prepotentials of the new multiplet.Comment: 15 page
Method of preparing zinc orthotitanate pigment
Zinc orthotitanate suitable for use as a pigment for spacecraft thermal control coatings is prepared by heating a slightly zinc deficient reaction mixture of precipitated oxalates of zinc and titanium. The reaction mixture can be formed by coprecipitation of zinc and titanium oxalates from chloride solution or by mixing separately precipitated oxalates. The mixture is first heated to 400 to 600 C to remove volatiles and is then rapidly heated at 900 to 1200 C. Zinc orthotitanate produced by this method exhibits the very fine particle size needed for thermal control coatings as well as stability in a space environment
Is Employer-Based Health Insurance a Barrier to Entrepreneurship?
The focus on employer-provided health insurance in the United States may restrict business creation. We address the limited research on the topic of âentrepreneurship lockâ by using recent panel data from matched Current Population Surveys. We use difference-in-difference models to estimate the interaction between having a spouse with employer-based health insurance and potential demand for health care. We find evidence of a larger negative effect of health insurance demand on the entrepreneurship probability for those without spousal coverage than for those with spousal coverage. We also take a new approach in the literature to examine the question of whether employer-based health insurance discourages entrepreneurship by exploiting the discontinuity created at age 65 through the qualification for Medicare. Using a novel procedure of identifying age in months from matched monthly CPS data, we compare the probability of business ownership among male workers in the months just before turning age 65 and in the months just after turning age 65. We find that business ownership rates increase from just under age 65 to just over age 65, whereas we find no change in business ownership rates from just before to just after for other ages 55-75. Our estimates provide some evidence that "entrepreneurship lock" exists, which raises concerns that the bundling of health insurance and employment may create an inefficient allocation of which or when workers start businesses.Self-employment, entrepreneurship, health insurance
- âŠ