5,714 research outputs found
Variability of the HeI5876 A line in early type chemically peculiar stars
Chemically peculiar stars present spectral and photometric variability with a
single period. In the oblique rotator model, the non homogeneous distribution
of elements on the stellar surface is at the origin of the observed variations.
As to helium weak stars, it has been suggested that photometric and helium line
equivalent width variations are out of phase. To understand the behaviour of
helium in CP stars, we have obtained time resolved spectra of the HeI5876 A
line for a sample of 16 chemically peculiar stars in the spectral range B3 --
A1 and belonging to different sub-groups. The HeI5876 A line is too weak to be
measured in the spectra of the stars HD 24155, HD 41269, and HD 220825. No
variation of the equivalent width of the selected He line has been revealed in
the stars HD 22920, HD 24587, HD 36589, HD 49606, and HD 209515. The equivalent
width variation of the HeI5876 A line is in phase with the photometric
variability for the stars HD 43819, HD 171247 and HD 176582. On the contrary it
is out of phase for the stars HD 28843, HD 182255 and HD 223640. No clear
relation has been found for the stars HD 26571 and HD 177003.Comment: 8 pages, 9 figures. 1998, A&AS in pres
Uniform non-stoichiometric titanium nitride thin films for improved kinetic inductance detector array
We describe the fabrication of homogeneous sub-stoichiometric titanium
nitride films for microwave kinetic inductance detector (mKID) arrays. Using a
6 inch sputtering target and a homogeneous nitrogen inlet, the variation of the
critical temperature over a 2 inch wafer was reduced to <25 %. Measurements of
a 132-pixel mKID array from these films reveal a sensitivity of 16 kHz/pW in
the 100 GHz band, comparable to the best aluminium mKIDs. We measured a noise
equivalent power of NEP = 3.6e-15 W/Hz^(1/2). Finally, we describe possible
routes to further improve the performance of these TiN mKID arrays.Comment: 7 pages, 4 figures, submitted to Journal of low temperature physics,
Proceedings of LTD-1
Interventional Ultrasound in Dermatology: A Pictorial Overview Focusing on Cutaneous Melanoma Patients
Cutaneous melanoma incidence is increasing worldwide, representing an aggressive tumor when evolving to the metastatic phase. High-resolution ultrasound (US) is playing a growing role in the assessment of newly diagnosed melanoma cases, in the locoregional staging prior to the sentinel lymph-node biopsy procedure, and in the melanoma patient follow-up. Additionally, US may guide a number of percutaneous procedures in the melanoma patients, encompassing diagnostic and therapeutic modalities. These include fine needle cytology, core biopsy, placement of presurgical guidewires, aspiration of lymphoceles and seromas, and electrochemotherapy
A new tool for food industrial plant simulation and IoT control
The general objective of this research is to create a Simulation Software allowing the Optimization and Control of an IoT system for food industry applications.
An industrial plant is today considered a complex system as it is often composed of many types of machines characterized by a strong temporal variation of the productions.
The three missing factors to accomplish what above are:
• Simulation;
• Implementation of communicating objects also called IoT (Internet of Things) systems.
• Intelligent control;
In this paper, we show the tools developed and implemented in the Simulation software used to model a
physical industrial process by mean of a user-friendly graphic interface allowing interactively defining different
plant configurations, through the selection of basic graphic elements and their appropriate connection.
The software has been developed in Unity, a cross-platform engine used to create three-dimensional, twodimensional,
virtual reality, and augmented reality, as well as simulations.
The software consists of the following main sections:
• library;
• creation and management of the process scheme;
• simulation.
The "library" section contains the elements (blocks) used in the process scheme, to be completed with functions describing their specific behaviour. These elements represent physical components and logical connectors that allow connecting the different blocks generating an oriented graph.The "creation and management of the process scheme" section is the graphical interface through which new configurations can be created. In particular, the connectors correspond to a flow of information from one block to another and contain the output variables determined by the function of the starting block. These values are used as input in the arrival block.
The "simulation" section allows simulating of previously designed configurations
A real case study of a full-scale anaerobic digestion plant powered by olive by-products
The anaerobic digestion plant studied in this paper is one of the first full-scale plants using olive oil by-products. This is a two-stage plant with a power of 100 kWe. Two tests were performed: the first on olive pulp and pitted pomace and the second on biomass consisting of 10% crushed cereal. In both cycles, the retention time was 40 days. The production of biogas was between 51 and 52 m3/h, with limited fluctuations. The specific production values of biogas indicate that a volume of biogas greater than 1 m3/kg was produced in both tests. The produced biogas had a methane percentage of about 60% and the specific production (over total volatile solids, TVS) of methane was of the order of 0.70 m3methane/kgTVS. FOS/Alk (ratio between volatile organic acids and alkalinity) was always lower than 1 and tended to decrease in the second digester, indicating a stable meth-anogenic phase and the proper working of the methanogenic bacteria in the second reactor. The concentration of incoming biomass TPC (total polyphenols content) can vary significantly, due to the seasonality of production or inadequate storage conditions, but all measured values of TPC, between 1840 and 3040 mg gallic acid kg−1, are considered toxic both for acidogenic and methano-genic bacteria. By contrast, during the process the polyphenols decreased to the minimum value at the end of the acidogenic phase, biogas production did not stop, and the methane percentage was high
New modelling approach for the energy and steam consumption evaluation in a fresh pasta industry
The agri-food industry has a fundamental role in the Italian and European economy and is characterized by the need to reduce energy costs and emissions. Therefore, it is essential for food companies to give due consideration to the energy efficiency of the processes, to reduce production costs, without sacrificing the quality of primary production and maintaining adequate levels of competitiveness on the market. In this study, a theoretical and experimental mass and energy balance of the production process of fresh pasta was made, also considering the energy contributions of a cogeneration plant recently built in the company subject of the experimental study. The final aim was to determine scientific values of specific energy consumption for this type of production by mean a new modelling approach. The mass and energy balances were carried out for the production line of fresh semolina pasta, as well as for the cogeneration plant; monitoring the flows of raw materials and steam that characterize the production process. The results of this study can be generalized to all production processes of the same type and, in the specific case, constitute a decisive logical step for the definition of the energy recovery solutions to be adopted in the company studied, in relation to their economic-production needs
Night-time shift work and related stress responses: A study on security guards
Work-related stress can induce a break in homeostasis by placing demands on the body that are met by the activation of two different systems, the hypothalamic\u2013pituitary\u2013adrenal axis and the sympathetic nervous system. Night-shift work alters the body\u2019s exposure to the natural light\u2013 dark schedule and disrupts circadian (daily) rhythms. The greatest effect of night-shift work is the disruption of circadian rhythms. The impact that these disruptions may have on the pathogenesis of many diseases, including cancer, is unknown. This study aims to discover the relationship among three different job activities of security guards and their stress-related responses by evaluating salivary cortisol levels and blood pressure. Methods: Ninety security guards, including night-time workers and night-time and daily-shift workers, were recruited for this study. Each security guard provided two saliva samples before and after three scheduled time points: (i) at 22:00, (ii) at 06:30, and (iii) at 14:00. Results: The results of the study showed a significant alteration in cortisol levels. Night-time shift cortisol levels significantly increased before and after the work shifts. A physiological prevalence of the vagal tone on the cardiocirculatory activity was found during night-shift work. Conclusions: This study indicates that cortisol levels and blood pressure are sensitive markers of biological responses to severe work stress. Shift-change consequences may occur at the end of the night shift when there is a significant increase in the cortisol level and a significant variation in cardiovascular parameters
Determinants associated with obesity and physical activity in the public and private schools of the city of palermo
Introduction: Obesity is a medical condition associated with premature death and it is a risk factor for many chronic diseases. In this context, performing a regular physical activity promotes a healthy lifestyle, with significant health benefits. The aim of the study was to investigate behaviors that increase the risk of obesity and the determinants that encourage physical activity among adolescents. Materials and methods: The HBSC (Health Behavior in School-aged Children) questionnaire was administered to students in Palermo's private and public schools. For the sampling of public schools the protocol of the HBSC Surveillance System was followed; for the private ones it was opportunistic. Results: Private school students are more likely to exercise more than 3 days per week (OR 1.58) and are more likely to exercise more than 2 times a week (OR 2.08). Obese students in private schools in Palermo are more likely to perform physical activity for less than 3 days a week (OR 3.52) and a higher risk of not having breakfast (OR 10.11) and a snack between main meals (OR 3.82) every day. For all the schools examined, it emerged that obese subjects are more likely not to consume fruit (OR 3.13), to stay more than 6 hours a day in front of PCs and video games (OR 3.24) and more than 2 hours a day in front of TV (OR 3.79). Male students are more likely to perform physical activity for more than 3 days per week (OR 1.48) and intense physical activity at least 2 times per week (OR 1.76) Conclusions: It is necessary to intervene early with training on school and family in order to promote correct and responsible food choices and increase the level of physical activity among students. Therefore prevention interventions must be an integral part of coherent strategies based on tests of agreed effectiveness in order to minimize the risk linked to the development of diseases
Experimental trials and dynamical simulation of the potential biogas production in a frozen food industry
Food industry determines the production of huge quantities of by-products, solid and waste. Identifying an ecological and economically viable solution for the management and disposal of horticultural wastes helps reducing the environmental impact of this kind of industries. In this paper a biogas production potential was obtained during one year of hourly data observation in a frozen food industry through dynamical simulation. This provides useful data for the correct management of an anaerobic digestion plant using the horticultural wastes coming from the production lines.The experimental analysis was carried out in an Italian cooperative firm, that process and market canned foods and frozen foods. Material flows were analysed especially considering the production of wastes. From the quantitative point of view, the hourly, daily, monthly, and annual flows of the single by-products of the studied processing cycle were determined. A dynamical simulation tool was developed to determine an optimized waste management procedure for biogas production. Design criteria was obtained for a biomass treatment to recover the organic substance for biogas production
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