Evaluating Butterfly Orbits in the Earth-Moon Corridor for SSA, Lunar Surface Surveillance, and Cislunar Disposal

The increased space activity in the region of cislunar space has created a high demand to identify, track, and monitor Resident Space Objects (RSOs) and provide cislunar disposal routes for RSOs. This research investigates the practicality of various satellite maneuvers between orbits chosen from the butterfly and dragonfly orbit families. Several simulated trajectories are compared to show the feasibility of performing a maneuver in cislunar and lunar space between the L1 and L2 Lagrange points. Additionally, lunar surface space situational awareness (SSA) capabilities of northern and southern butterfly (BN/BS) orbits were evaluated and compared to provide the most favorable dynamic model for space-based lunar surveillance. This research also investigates the practicality of various trajectories for decommissioned satellites chosen from unstable manifolds in the BS orbit family. Gravitational effects from the Earth, Moon, and Sun are incorporated into several simulated trajectories in order to best evaluate their feasibility for cislunar disposal. Results of this research show that butterfly orbits can be highly effective for observing RSOs in or near a dragonfly orbit, with all scenarios providing at least 90% visibility year-round. Further analysis concludes that the butterfly orbit family is unfavorable for a primarily lunar surveillance mission. Additionally, various manifold-based trajectories originating from a butterfly orbit were found to be optimal for cislunar disposal, particularly for decommissioning satellites

First responder safety in the event of a dirty bomb detonation in urban environment

The malevolent dispersion of radioactive material, with the aim of contaminating people and the environment, is considered a credible terroristic threat. This article analyzes a hypothetical Dirty Bomb detonation in an urban area, estimating the radiological consequences to the involved population and to first responders. The dispersion of radioactive material is simulated using the HOTSPOT code, considering the explosion of devices containing (alternatively) 60Co, 137Cs, 192Ir, 238Pu or 241Am sources, frequently used in medical or industrial settings. Each source is evaluated separately. The resulting ground deposition is used to calculate the effective dose received by first responders in two different scenarios. Based on the dispersed radionuclide, the influence of the use of personal protective respirators is analyzed. Confirming previous published results, this article illustrates that the radioactive material is diluted by the detonation, resulting in relatively low doses to the general public. However, the emergency workers' stay time in the most contaminated area must be carefully planned, in order to limit the received dose. Due to the general fear of radiation, extensive psychological effects are expected in the public, irrespective of the evaluated radiation dose

Bringing Particle Scale Properties into Descriptions of Powder Behavior through the Enhanced Centrifuge Method

Inconsistent powder behavior introduces problems such as agglomeration, poor flowability, dust hazards, and segregation that decrease efficiency in powder processing environments. Understanding how a powder interacts with a surface at the particle scale provides insight into how to accommodate individual particle properties and avoid process deficiencies. This project uses an enhanced centrifuge technique to evaluate the adhesion between a stainless-steel surface and a powder comprised of fluorescent particles. Particles are deposited onto stainless steel plates which are rotated in a centrifuge. The adhesion properties are monitored by tracking the rotational speed at which particles of a known size are removed from the steel. To model the adhesion, a simulator was produced in MATLAB to map an ideal model to the experimental observations. In reality, the particles and steel are rough, and the particles are nonuniform in shape. The ideal case assumes the particles are smooth spheres and the steel is smooth. A modified van der Waals force model describes the observed forces. Within this model, a Hamaker constant, which usually describes only the effect of composition on the van der Waals force, is tuned to also describe the effects of the non-uniformity of the particles. This creates a distribution of ‘effective Hamaker constants’ that describes particle scale effects on the adhesion between the bulk powder and the stainless steel. This approach will allow industry to account for the effects of surface roughness, particle shape, and particle size when designing powder processing operations

Operational indications and self-assessment checklist for internal audits in cyclotron facilities – an Italian experience

In this work the authors intend to provide useful operational indications to approach, with the best practice, the design of a cyclotron facility for the production of PET radioisotopes. Special attention is devoted to organizational and safety aspects. In order to prompt toward a systematic application of the proposed indications, the article presents them in form of a specific self-assessment checklist, consisting in a list of items which address the design process in all the different phases. This checklist represents a useful toolbox both in the design stage and subsequently for the development of internal audits

The turn of the valve: representing with material models

Many scientific models are representations. Building on Goodman and Elgin’s notion of representation-as we analyse what this claim involves by providing a general definition of what makes something a scientific model, and formulating a novel account of how they represent. We call the result the DEKI account of representation, which offers a complex kind of representation involving an interplay of, denotation, exemplification, keying up of properties, and imputation. Throughout we focus on material models, and we illustrate our claims with the Phillips-Newlyn machine. In the conclusion we suggest that, mutatis mutandis, the DEKI account can be carried over to other kinds of models, notably fictional and mathematical models

Preliminary evaluations of the environmental impact for the production of 99Mo by fusion neutrons

ENEA is developing an accelerator-driven 14 MeV neutron source exploiting the deuterium–tritium fusion reaction to produce 99Mo medical radioisotope as an alternative production route not based on fission reactors. It is expected that, during normal operation, a number of radionuclides, generated by means of neutron irradiation on the raw material (natural Molybdenum), will be produced and managed. The present manuscript, as foreseen by national law, discusses a hypothetical scenario to test the environmental screening models, in turn evaluating the mechanisms and parameters which affect and control the path of liquid effluents potentially released during normal operation of the facility. The aim is to estimate the amount of radioactivity to be operated and the fraction potentially discharged in this hypothetical scenario, so as to ensure that the radioactive material can be managed without any risk for the population and the environment, according to national regulations and thoroughly fulfilling the international guidelines

Native cattle breeds of Southern Italy: karyological profile

Italian typical products of animal origin are strictly linked to native breeds. Their protection requires control of their reproductive and productive abilities. Hence the need for karyological studies to identify subjects with chromosome abnormalities linked to hypofertility or sterility. We report the results of karyological analyses carried out from January 2008 to December 2008 on 145 cattle of native breeds (Agerolese, Cinisara, Modicana and Podolica) reared in Southern Italy so as to evaluate and characterize the presence of chromosome abnormalities in subjects with normal phenotypes. Besides the 128 karyologically normal subjects (2n=60, XY and 2n=60, XX), 17 were carriers of rob (1;29) and one male was a carrier of cellular chimerism 2n=60, XX/XY. According to our data there is a high frequency of rob (1;29) in Cinisara and Podolica breeds while in Agerolese there was only one case of rob (1;29) and none in Modicana

Subclinical atherosclerosis in patients with psoriatic arthritis: a case-control study. Preliminary data

Objective: The aim of this study was to evaluate the prevalence of subclinical atherosclerosis in patients with psoriatic arthritis (PsA), correlated with some traditional risk factors of atherosclerosis and with PsA-related disease factors. Methods: Forty-one patients and 41 healthy subjects were evaluated for intima-media thickness (IMT) and flow-mediated dilation (FMD), using carotid duplex scanning. IMT values were expressed like IMT mean (cumulative mean of all the IMT mean) and M-MAX (cumulative mean of all the higher IMT). Subclinical atherosclerosis markers were correlated with age, body mass index (BMI) and blood pressure in both groups, with duration of arthritis, duration of psoriasis, tender and swollen joints, BASDAI (Bath Ankylosing Spondylitis Disease Activity Index), BASFI (Bath Ankylosing Spondylitis Functional Index), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in patients. Results: IMT mean and M-MAX were both higher in PsA patients compared with controls (0.7±0.15 vs 0.62±0.09 mm; p<0.01 and 0.86±0.21 vs. 0.74±0.13 mm; p<0.01 respectively). FMD was smaller in patients than in controls (5.9±2 vs 7.5±2.8%; p<0.01). Univariate analysis showed a correlation between IMT mean and SBP (r=0.217; p=0.05) and a correlation between M-MAX and age (r=0.392; p<0.001), BMI (r=0.252; p<0.05), SBP (r=0.446; p<0.001) in both groups. In PsA patients M-MAX resulted correlated with ESR (r=0.338; p<0.05) and BASDAI (r=0.322; p<0.05). Conclusions: PsA patients exhibited endothelial dysfunctions which is an early marker of subclinical atherosclerosis, as well as an higher IMT. An interesting correlation between M-MAX and PsA activity index (ESR and BASDAI) was found

Thermal neutron detection by means of Timepix3

Thermal neutron detection plays a crucial role in numerous scientific and technical applications such as nuclear reactor physics, particle accelerators, radiotherapy,materials analysis and space exploration. There are several challenges associated with the accurate identification and quantification of thermal neutrons. The present work proposes a detailed characterization of a Timepix3 (TPX3) detector equipped with a Lithium Fluoride (6LiF) converter in order to study its response to thermal neutrons that are identified through the 6Li(n,α)3H reaction. The TPX3-based test system has been installed at the HOTNES facility in ENEA and the analysis highlighted its excellent performance showing high effectiveness in the identification of neutrons through morphological analysis of tracks produced by alpha and triton particles, after accurate discrimination from the gamma background. With the use of Monte Carlo simulations, it has been demonstrated that the main contribution is due to tritons and its signal can be used effectively in the identification of thermal neutrons obtaining an efficiency of 0.9 % for 25 meV neutrons. This allows the TPX3 to have important applications as an environmental monitor for thermal neutrons. This monitoring system can be simply realized and is easy to manage because of its compact size and its digital acquisition that allows a real-time analysis