A Super-Conducting Linac Driver for the HFBR

This paper reports on the feasibility study of a proton Super-Conducting Linac (SCL) as a driver gor the High-Flux Breader Reactor (HFBR) at Brookhaven National Laboratory (BNL). The Linac operates in Continuos Wave (CW) mode to produce an average 10 MW of beam power. The Linac energy is 1.0 GeV. The average proton beam intensity is 10 mA.Comment: 3 page

Efficiency optimization for Atomic Frequency Comb storage

We study the efficiency of the Atomic Frequency Comb storage protocol. We show that for a given optical depth, the preparation procedure can be optimize to significantly improve the retrieval. Our prediction is well supported by the experimental implementation of the protocol in a \TMYAG crystal. We observe a net gain in efficiency from 10% to 17% by applying the optimized preparation procedure. In the perspective of high bandwidth storage, we investigate the protocol under different magnetic fields. We analyze the effect of the Zeeman and superhyperfine interaction

The boundary between urban and natural landscape

The images of empty cities in the pandemic era surprised us, every economic activity, every type of transport has stopped making urban centers like ghost areas. The frame that shocked the world is certainly the one captured by Copernicus, a space satellite of the European Space Agency (ESA). He showed us a planet earth that returns to breathe, for the first time in decades the smog clouds have no longer enveloped the earth's surface. Despite the negative aspects related to health and sociality, there were many positive aspects that allowed us to think about how important the environment is about a naturalistic-environmental point of view as well as for psychological well-being. Many minor historic centers and naturalistic areas have welcomed smart-working workers, favoring a repopulation of ancient uninhabited villages or countryside areas disconnected by large urban centers. These are decentralized places that are marked by a boundary between urban and natural landscape, a boundary that in recent decades has proved increasingly weak and susceptible. The human evolution has shown us that migrations occurred to find food and comfortable places, hence the formation of the first villages to create places for the exchange of goods and knowledge, understood as cultural exchange. From the primordial human evolution up to contemporary history, needs have changed and cities have changed because of these. The pandemic has reminded us, however, how important are the places that contain memories. That border, so vulnerable, is the sustainable development goal for the future, human beings must invest to protect. It’stimeto ward the memory, the cultural identity and the natural capital of these places. Re-inhabiting, re-evaluating and rehabilitating these places could be the way to achieve a sustainable future. In the waste era increasing by pollution and frenetic city life, many people are trying to reconcile themselves with nature rhythm, with an ancient well-being of self-production daily food. The communities that live these places need to be included into a political-social process, they must be the subjects of planning. The past can be the way to approach the future

Polymer induced condensation of dna supercoils

Macromolecular crowding is thought to be a significant factor driving DNA condensation in prokaryotic cells. Whereas DNA in prokaryotes is supercoiled, studies on crowding-induced DNA condensation have so far focused on linear DNA. Here we compare DNA condensation by poly(ethylene oxide) for supercoiled and linearized pUC18 plasmid DNA. It is found that supercoiling has only a limited influence on the critical amount of PEO needed to condense plasmid DNA. In order to pack DNA supercoils in condensates, it seems inevitable that they must be deformed in one way or another, to facilitate dense packing of DNA. Analytical estimates and Monte Carlo simulations indicate that packing of DNA supercoils in condensates is most likely facilitated by a decrease of the superhelical diameter rather than by unwinding of the supercoil

Light-cone fluctuations and the renormalized stress tensor of a massless scalar field

We investigate the effects of light-cone fluctuations over the renormalized vacuum expectation value of the stress-energy tensor of a real massless minimally coupled scalar field defined in a ($d+1$)-dimensional flat space-time with topology ${\cal R}\times {\cal S}^d$. For modeling the influence of light-cone fluctuations over the quantum field, we consider a random Klein-Gordon equation. We study the case of centered Gaussian processes. After taking into account all the realizations of the random processes, we present the correction caused by random fluctuations. The averaged renormalized vacuum expectation value of the stress-energy associated with the scalar field is presented

A Cost-Benefit Analysis for the Implementation of Lean Logistics to Aircraft Structural Repair at the Air Force Material Command\u27s Warner Robins Air Logistics Center/Depot

This research conducts a cost-benefit analysis of the implementation of lean logistics to the repair of aircraft structural components at the Air Force Material Command\u27s (AFMC) Warner Robins Air Logistics Center (WR-ALC). A literature review identifies new business practices in the automotive industry, collectively \u27termed lean production, that were translated by the RAND Corporation into a modified Air Force logistics system-- the lean logistics model. Theoretical costs and benefits from the lean logistics model are translated into empirical costs and benefits associated with aircraft structural repair. The cost-benefit analysis results clearly demonstrate that express distribution costs for the sizable aircraft structural components significantly contribute to costs exceeding benefits for this specific depot logistics subsystem process

Beginning With Pictures

This paper shows how simple drawings were used to teach English to a beginning-level language class. It contains a syllabus outlining the material covered in a ten-week course and reproductions of the pictures with commentary on how they were drawn and used. The main objective in using this type of drawing was to help students find the meaning of language within themselves, as they created it. The effectiveness of these pictures in teaching basic English led to the included in-depth analysis of how humans perceive, the elementary state of mind and viewpoint (as seen in the works of three groups of beginning artists: prehistoric man, children and the American Primitive), how art and language express and communicate, and the affirmation of the value of considering all of these in teaching beginning-level language students

The Lense-Thirring effect in the Jovian system of the Galilean satellites and its measurability

In this paper we investigate the possibility of measuring the post-Newtonian general relativistic gravitomagnetic Lense-Thirring effect in the Jovian system of its Galilean satellites Io, Europa, Ganymede and Callisto in view of recent developments in processing and modelling their optical observations spanning a large time interval (125 years). The present day best observations have an accuracy between several kilometers to few tens of kilometers, which is just the order of magnitude of the Lense-Thirring shifts of the orbits of the Galilean satellites over almost a century. From a comparison between analytical development and numerical integration it turns out that, unfortunately, most of the secular component of the gravitomagnetic signature is removed in the process of fitting the initial conditions. Indeed, an estimation of the magnitude of the Lense-Thirring effect in the ephemerides residuals is given; the resulting residuals have a maximum magnitude of 20 meters only (over 125 years).Comment: Latex, 10 pages, 4 tables, 3 figures, 27 references. Invited paper for a Special Issue of Int. J. Mod. Phys. D on the Lense-Thirring effect, D. Grumiller edito

On the time delay in binary systems

The aim of this paper is to study the time delay on electromagnetic signals propagating across a binary stellar system. We focus on the antisymmetric gravitomagnetic contribution due to the angular momentum of one of the stars of the pair. Considering a pulsar as the source of the signals, the effect would be manifest both in the arrival times of the pulses and in the frequency shift of their Fourier spectra. We derive the appropriate formulas and we discuss the influence of different configurations on the observability of gravitomagnetic effects. We argue that the recently discovered PSR J0737-3039 binary system does not permit the detection of the effects because of the large size of the eclipsed region.Comment: 7 pages, 2 eps figures, RevTex, to appear in Physical Review