Advances in Ground Transmitters for the NASA Deep Space Network

The Deep Space Network (DSN), managed by the Jet Propulsion Laboratory for NASA, is equipped with multiple microwave transmitters ranging in average radiated power from 200 W to 400 kW. The transmitters are used for routine or emergency communication with spacecraft, for navigation, and for radio science tasks. The latest advances in transmitter engineering were implemented in a new generation of 20-kW dual-band transmitters developed for the DSN 34-m beam waveguide antennas. Innovations include additional X-band communication capability for near Earth missions, new c, automated calibration, improved and expanded computerized monitoring and diagnostics, reduced cabling, and improved maintainability. The innovations were very beneficial for the DSN ldquooverloadrdquo during the Mars 2003/2004 missions and will benefit other missions throughout the next decade. This paper describes the current design of the new transmitters and possible future developments.     

Scheduling flow lines with buffers by ant colony digraph

This work starts from modeling the scheduling of n jobs on m machines/stages as flowshop with buffers in manufacturing. A mixed-integer linear programing model is presented, showing that buffers of size n ? 2 allow permuting sequences of jobs between stages. This model is addressed in the literature as non-permutation flowshop scheduling (NPFS) and is described in this article by a disjunctive graph (digraph) with the purpose of designing specialized heuristic and metaheuristics algorithms for the NPFS problem. Ant colony optimization (ACO) with the biologically inspired mechanisms of learned desirability and pheromone rule is shown to produce natively eligible schedules, as opposed to most metaheuristics approaches, which improve permutation solutions found by other heuristics. The proposed ACO has been critically compared and assessed by computation experiments over existing native approaches. Most makespan upper bounds of the established benchmark problems from Taillard (1993) and Demirkol, Mehta, and Uzsoy (1998) with up to 500 jobs on 20 machines have been improved by the proposed ACO.     

Potential of diffuse scatterer interferometry for monitoring CO2 storage sites in European contexts (land cover types)

This article proposes to test the feasibility of long-term surface deformation monitoring based on synthetic aperture radar (SAR) interferometry on carbon dioxide (CO₂) storage sites with land cover representative of potential European injection sites (agricultural or forests with minimum built-up land cover). Because no operational injection site is currently active in Europe, a SAR data set (based on EnviSAT–ASAR spaceborne data) is simulated by combining SAR scenes acquired over a potential future European injection site with deformation measurements from SAR analysis carried out on the In-Salah (Algeria) CO₂ injection demonstrator site. The study shows that under such conditions, both persistent scatterer interferometry (PSI) and diffuse scatterer (DS) interferometry appear insufficient to provide a sufficiently dense measurement network to characterize surface deformation correctly. Alternative solutions, to be investigated in further studies, include the use of data archives with shorter acquisition time spans (e.g. Sentinel-1 data when available) or installation of corner reflectors. The cost of the latter mixed space/ground solution must be evaluated with respect to conventional ground-based measurement methods in the proposed context.     

ON THERMOPIEZOELECTRICITY FOR POROUS MATERIALS

This article is concerned with some basic theorems in the theory of thermopiezoelectric materials with voids. We establish uniqueness and reciprocity relations both for quasi-static and dynamic theory. A minimum principle of Reiss and Haug type is presented in the context of the quasi-static theory.     

Results of a 3D seismic survey at the Travale (Italy) test site

In the last 15 years geothermal exploration in Tuscany, Italy, has addressed deep reservoirs (depth ≥ 3000 m), hosted within complex geological systems, such as metamorphic formations and/or intrusive bodies. Reservoir productivity is linked to fractured and permeable zones that are rather confined and not uniformly distributed. In this context, the seismic methods represent one of the most reliable geophysical techniques for locating potential drilling targets. A 3D seismic survey has been acquired at the Travale test site, and its results have been used to develop a geological and structural model of the site, and to identify and characterize fractured zones inside the deep geothermal reservoir. A correlation between a high-amplitude reflector (H marker) and fractured contact-metamorphic rocks has been highlighted. More than 70% of the total geothermal fluid production at the Travale area comes from this seismic marker.     

Numerical prediction of turbulent flow and heat transfer in helically coiled pipes

Computational results were obtained for turbulent flow and heat transfer in curved pipes, representative of helically coiled heat exchangers. Following a grid refinement study, grid independent predictions from alternative turbulence models (k–?, SST k–ω and RSM–ω) were compared with DNS results and experimental pressure drop and heat transfer data. Using the SST k–ω and RSM–ω models, pressure drop results were in excellent agreement with literature data and the Ito correlation. For heat transfer, the literature is not comparably complete or accurate, but a satisfactory agreement was obtained in the range of available data. Unsatisfactory results, both for pressure drop and heat transfer, were given by the k–? model with wall functions. Following the validation study, the RSM–ω model was used to compute friction coefficients and Nusselt numbers in the range Re = 1.4·10⁴–8·10⁴, Pr = 0.7–5.6 and δ (coil curvature) = 3·10^?3–0.3. Power-law correlations were found unsuitable to fit the Re-, Pr- and δ-dependence of the Nusselt number, while the use of a properly formulated momentum-heat transfer analogy collapsed all results with high accuracy.     

Projective Architecture

Michele Sbacchi investigates the real influence of the notion of projection on architectural design before and during the age of Guarini. He takes into consideration concepts such as light and shadow, abstract line, plane, section, projective geometry and perspective. To do this he looks at the ideas of Gregorius Saint Vincent, Alberti, Guarini, Desargues and de l’Orme, among others.     

Traceability as a means to investigate supply chain sustainability: the real case of a leather shoe supply chain

In recent years, the growing attention to environmental challenges has shown that these issues are becoming of more and more interest to both research and industry. Companies are expected to ensure their products are fully traceable and more sustainable, which requires the involvement of all of the actors in the production network. According to this aim, this study proposes a structured approach that uses the traditional traceability concept as a means to identify the main information needed to assess environmental impacts along the whole supply chain (SC). The proposed approach is composed of four main steps: (i) SC modelling to identify all stakeholders and their inter-relations, (ii) data sharing to collect all relevant data, (iii) data elaboration to calculate performance at different levels of detail and (iv) result interpretation to optimise the SC. The distributed implementation of the approach at different SC steps represents a useful means to practically realise a sustainable SC management. A case study involving a leather shoe SC is used to demonstrate the effectiveness of the approach in identifying criticalities, supporting the selection of the most appropriate suppliers and correctly setting a management strategy towards the optimisation of internal and external traceability and environmental sustainability performances.     

Strong normalization property for second order linear logic

The paper contains the first complete proof of strong normalization (SN) for full second order linear logic (LL): Girard’s original proof uses a standardization theorem which is not proven. We introduce sliced pure structures (sps), a very general version of Girard’s proof-nets, and we apply to sps Gandy’s method to infer SN from weak normalization (WN). We prove a standardization theorem for sps: if WN without erasing steps holds for an sps, then it enjoys SN. A key step in our proof of standardization is a confluence theorem for sps obtained by using only a very weak form of correctness, namely acyclicity slice by slice. We conclude by showing how standardization for sps allows to prove SN of LL, using as usual Girard’s reducibility candidates.     

Two new measures of attitudes about the acceptability of teen dating aggression.

Aggression in dating relationships is associated with attitudes that justify its use. Attitudes about dating aggression are targeted by prevention efforts, contributing to a need to measure these attitudes sensitively, accurately, and multidimensionally. We describe two new measures of attitudes about aggression, each tapping different attitudinal components, and compare their psychometric properties with an existing scale. The 1st assesses attitudes about physical aggression in provocative situations. The 2nd taps attitudes about verbally aggressive, controlling, and jealous tactics against a dating partner. Data from 2,313 high school students were factor analyzed and cross-validated for each new scale. Compared with an existing measure, the scales had comparable levels of reliability and validity and improved response distributions. A 2nd-order factor analysis lends support to a multidimensional view of attitudes about dating aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)