Suchergebnisse

AbstractAn algorithm is derived for allocating finite resources in discrete amounts to a number of activities subject to a set of nonlinear constraints. The algorithm differs from those previously described in that the amount of the resource consumed for an additional unit of any one activity need not be constant. The algorithm is then applied to the problem of allocating a spares budget when repair of failed subsystems is allowed and the cost of unit subsystems is a function of the number to be spared. Two models are presented: one with an unrestricted repair facility, exponential failure distributions, and general repair distributions; and another with more limited repair and exponential failure and repair distributions.

IN THIS ARTICLE, A NUMBER OF CONSERVATIVE LEADERS GIVE MID-TERM GRADES TO PRESIDENT GEORGE BUSH AND SEVERAL TOP OFFICIALS AND CABINET MEMBERS, INCLUDING CHIEF OF STAFF SUNUNU AND VICE PRESIDENT QUAYLE.

THE AUTHORS ENDEAVOR TO DEFINE U.S. INTERESTS IN THE STATES THAT FORMERLY MADE UP YUGOSLAVIA AND TO SPECIFY WHAT U.S. POLICY SHOULD BE TOWARD THE NEW BALKAN STATES.

Open Access Article. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. ; Emitted from the oceans, iodine-bearing molecules are ubiquitous in the atmosphere and a source of new atmospheric aerosol particles of potentially global significance. However, its inclusion in atmospheric models is hindered by a lack of understanding of the first steps of the photochemical gas-to-particle conversion mechanism. Our laboratory results show that under a high humidity and low HOx regime, the recently proposed nucleating molecule (iodic acid, HOIO2) does not form rapidly enough, and gas-to-particle conversion proceeds by clustering of iodine oxides (IxOy), albeit at slower rates than under dryer conditions. Moreover, we show experimentally that gas-phase HOIO2 is not necessary for the formation of HOIO2-containing particles. These insights help to explain new particle formation in the relatively dry polar regions and, more generally, provide for the first time a thermochemically feasible molecular mechanism from ocean iodine emissions to atmospheric particles that is currently missing in model calculations of aerosol radiative forcing. © 2020, The Author(s). ; This study has received funding from the European Research Council Executive Agency under the European Union's Horizon 2020 Research and Innovation programme (Project "ERC-2016-COG 726349 CLIMAHAL"). J.C.G.M. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), the Ramon y Cajal Program (RYC-2016-19570) and the National I + D + i Program (RTI2018-095330-B-100). We thank the Holland Computing Center of the University of Nebraska—Lincoln for providing computing resources. ; Peer reviewed