A high voltage, low current power source for long term space applications

Experimental design of high voltage low current power source for unmanned, long term space missio

Structure determination of a brownmillerite Ca2Co2O5 thin film by Precession Electron Diffraction

Calcium cobaltite thin films with a ratio Ca/Co=1 were grown on (101)-NdGaO3 substrate by the pulsed laser deposition technique. The structure of the deposited metastable phase is solved using a precession electron diffraction 3D dataset recorded from a cross-sectional sample. It is shown that an ordered oxygen-deficient Ca2Co2O5+d perovskite of the brownmillerite-type with lattice parameters a= 0.546nm, b=1.488nm and c=0.546nm (SG: Ibm2) has been stabilized using the substrate induced strain. The structure and microstructure of this metastable cobaltite is further discussed and compared to related bulk materials based on our transmission electron microscopy investigationsComment: 13 pages, 10 figures, 2 tables, accepted in Phys. Rev.

Unmasking Uncle Sam: A Legal Test for Defining and Identifying State Media

In December 2018, the Chair of the House Foreign Affairs Committee published a report detailing how the U.S. Agency for Global Media, the central federal state media agency, illegally targeted social media ads at Americans at least 860 times from 2016 to 2018. The U.S. Agency for Global Media and other U.S. state media agencies have enormous resources, and if left unchecked, could unduly influence public opinion, threaten the free and independent press, and subvert democratic accountability. To address this growing concern, this Article proposes a new, comprehensive legal test for defining and identifying state media that incorporates existing approaches for analyzing government publications employed by the federal government and independent media platforms

Site systems engineering: Systems engineering management plan

The Site Systems Engineering Management Plan (SEMP) is the Westinghouse Hanford Company (WHC) implementation document for the Hanford Site Systems Engineering Policy, (RLPD 430.1) and Systems Engineering Criteria Document and Implementing Directive, (RLID 430.1). These documents define the US Department of Energy (DOE), Richland Operations Office (RL) processes and products to be used at Hanford to implement the systems engineering process at the site level. This SEMP describes the products being provided by the site systems engineering activity in fiscal year (FY) 1996 and the associated schedule. It also includes the procedural approach being taken by the site level systems engineering activity in the development of these products and the intended uses for the products in the integrated planning process in response to the DOE policy and implementing directives. The scope of the systems engineering process is to define a set of activities and products to be used at the site level during FY 1996 or until the successful Project Hanford Management Contractor (PHMC) is onsite as a result of contract award from Request For Proposal DE-RP06-96RL13200. Following installation of the new contractor, a long-term set of systems engineering procedures and products will be defined for management of the Hanford Project. The extent to which each project applies the systems engineering process and the specific tools used are determined by the project`s management

The evolution of a successful systems engineering organization at Hanford

As the systems engineering activities at the US Department of Energy`s Hanford reservation have matured, they have been placed in many positions within the management structure. Some of these have been more successful than others. This paper describes the organizational evolution of systems engineering over the last few years to its current successful configuration. Background The US Department of Energy (DOE) owns the 640 square mile Hanford reservation located in southeast Washington State (Figure 1). The Site has been operated for DOE by a team of contractors, who read like a Who`s Who in American Industry. Throughout its history from its founding in 1943 until 1991, Hanford`s primary mission was to produce special nuclear material for the nuclear weapons program. This mission resulted in significant quantities of radioactive and mixed waste that is stored on the site in a variety of forms. In addition much of the surface area, subsurface soil, and groundwater are contaminated to various degrees. The Reservation is located on the banks of the Columbia River, and the avoidance of contaminating the waterway that services the Pacific Northwest is a national concern. In 1991, the mission of the Hanford Site was changed from production to environmental cleanup. To support the development and execution of this mission, DOE directed that systems engineering principles be employed as key feature of the management approach. This paper describes the evolution of organizational configuration supporting systems engineering from a small ancillary activity to one which is now providing the technical basis for the integrated planning and execution of the cleanup mission. It also describes the work remaining to consolidate the existing systems-based processes into a fully integrated management structure

On Uniquely Closable and Uniquely Typable Skeletons of Lambda Terms

Uniquely closable skeletons of lambda terms are Motzkin-trees that predetermine the unique closed lambda term that can be obtained by labeling their leaves with de Bruijn indices. Likewise, uniquely typable skeletons of closed lambda terms predetermine the unique simply-typed lambda term that can be obtained by labeling their leaves with de Bruijn indices. We derive, through a sequence of logic program transformations, efficient code for their combinatorial generation and study their statistical properties. As a result, we obtain context-free grammars describing closable and uniquely closable skeletons of lambda terms, opening the door for their in-depth study with tools from analytic combinatorics. Our empirical study of the more difficult case of (uniquely) typable terms reveals some interesting open problems about their density and asymptotic behavior. As a connection between the two classes of terms, we also show that uniquely typable closed lambda term skeletons of size $3n+1$ are in a bijection with binary trees of size $n$.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/\mu m. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteriorating is not independent on particles' stopping power, thus illustrating that the radiation hardness of plastic scintillators can be strongly weakened under high excitation density in heavy ion environments.Comment: 5 figures, accepted in Nucl. Instrum. Methods

Stakeholder involvement in redefining Hanford`s Double-Shell Tank waste disposal program

Hanford`s Double-Shell Tank (DST) waste disposal program was redefined following serious challenges to the viability of the previous strategy due to increased regulatory requirements and operating expectations. Redefinition of the DST waste disposal program involved a far-reaching set of decisions and actions. A formal stakeholder involvement process was used to bring the concerns of outside groups into the definition and evaluation of alternative tank waste disposal strategies, broadening the participation and ownership of the revised program