Restoration of an active MV distribution grid with a battery ESS: A real case study

In order to improve power system operation, Battery Energy Storage Systems (BESSs) have been installed in high voltage/medium voltage stations by Distribution System Operators (DSOs) around the world. Support for restoration of MV distribution networks after a blackout or HV interruption is among the possible new functionalities of BESSs. With the aim to improve quality of service, the present paper investigates whether a BESS, installed in the HV/MV substation, can improve the restoration process indicators of a distribution grid. As a case study, an actual active distribution network of e-distribuzione, the main Italian DSO, has been explored. The existing network is located in central Italy. It supplies two municipalities of approximately 10,000 inhabitants and includes renewable generation plants. Several configurations are considered, based on: the state of the grid at blackout time; the BESS state of charge; and the involvement of Dispersed Generation (DG) in the restoration process. Three restoration plans (RPs) have been defined, involving the BESS alone, or in coordination with DG. A MATLAB®/Simulink® program has been designed to simulate the restoration process in each configuration and restoration plan. The results show that the BESS improves restoration process quality indicators in different simulated configurations, allowing the operation in controlled island mode of parts of distribution grids, during interruptions or blackout conditions. The defined restoration plans set the priority and the sequence of controlled island operations of parts of the grid to ensure a safe and better restoration. In conclusion, the results demonstrate that a BESS can be a valuable element towards an improved restoration procedure

Mense e personale addetto alle cucine: valutazione dei rischi occupazionali

The aim of the study is to evaluate the occupational risks among food service workers and cooks. During the occupational risks assessment the following risk factors must be evaluated: musculoskeletal disorders, chemical risk (cleaning kitchen work surface, dishes, utensils ecc.) biological risk (contact with foods or biological agents) cancerogenic risk (by baking smoke inhalation), and psycho-social stress. In this study the preventive measures and protective equipment to prevent health hazards for these workers have been evaluated (i.e. aspiration hood, adapted ventilation, chosen of less harmful methods of baking, ecc.). In particular the performance of rigid behavioural norms and hygienic procedures is very important for cooks and food service workers to reduce the risk of occupational infections

Phantom validation of quantitative Y-90 PET/CT based dosimetry in liver radioembolisation

Background PET/CT has recently been shown to be a viable alternative to traditional post-infusion imaging methods providing good quality images of 90Y-laden microspheres after selective internal radiation therapy (SIRT). In the present paper, first we assessed the quantitative accuracy of 90Y-PET using an anthropomorphic phantom provided with lungs, liver, spine, and a cylindrical homemade lesion located into the hepatic compartment. Then, we explored the accuracy of different computational approaches on dose calculation, including (I) direct Monte Carlo radiation transport using Raydose, (II) Kernel convolution using Philips Stratos, (III) local deposition algorithm, (IV) Monte Carlo technique (MCNP) considering a uniform activity distribution, and (V) MIRD (Medical Internal Radiation Dose) analytical approach. Finally, calculated absorbed doses were compared with those obtained performing measurements with LiF:Mg,Cu,P TLD chips in a liquid environment. Results Our results indicate that despite 90Y-PET being likely to provide high-resolution images, the 90Y low branch ratio, along with other image-degrading factors, may produce non-uniform activity maps, even in the presence of uniform activity. A systematic underestimation of the recovered activity, both for the tumor insert and for the liver background, was found. This is particularly true if no partial volume correction is applied through recovery coefficients. All dose algorithms performed well, the worst case scenario providing an agreement between absorbed dose evaluations within 20%. Average absorbed doses determined with the local deposition method are in excellent agreement with those obtained using the MIRD and the kernel-convolution dose calculation approach. Finally, absorbed dose assessed with MC codes are in good agreement with those obtained using TLD in liquid solution, thus confirming the soundness of both calculation approaches. This is especially true for Raydose, which provided an absorbed dose value within 3% of the measured dose, well within the stated uncertainties. Conclusions Patient-specific dosimetry is possible even in a scenario with low true coincidences and high random fraction, as in 90Y–PET imaging, granted that accurate absolute PET calibration is performed and acquisition times are sufficiently long. Despite Monte Carlo calculations seeming to outperform all dose estimation algorithms, our data provide a strong argument for encouraging the use of the local deposition algorithm for routine 90Y dosimetry based on PET/CT imaging, due to its simplicity of implementation

Development of a new in-water-phantom graphite calorimeter for the measurement of absorbed dose to water in medium energy x-ray beams

This paper summarizes the progress on the construction of a graphite calorimeter for the measurement of absorbed dose to water Dw in medium-energy filtered x-ray qualities, as part of the EMRP funded project “Metrology for radiotherapy using complex radiation fields” (MetrExtRT, http://radiotherapyemrp.eu/). The design and the construction of a new primary standard for absorbed dose to water (Dw) is shown, together with a presentation of the preliminary estimates of conversion factors, calculated by Monte Carlo using the EGSnrc code, and heat-transport calculations resulting from COMSOL simulations. The vacuum-gap-insulated calorimeter core has a thickness of 2 mm and a diameter of 20 mm. The graphite calorimeter is embedded in a PMMA waterproof sleeve and can be positioned at the desired measurement depth in a water phantom. Once completed, the new calorimeter will participate in an international comparison with other existing standards of absorbed dose to water for medium energy x-rays

Anxiety, musculoskeletal and visual disorders in video display terminal workers

Aim. The increase in the working population assigned to video display terminals (VDT) has led to ever growing attention to reports on health effects. We studied musculoskeletal and visual disorders and levels of anxiety in 2 groups of VDT operators with different tasks, in order to evaluate if they could be influenced by organizational and intrinsically working factors. Methods. The study included 190 VDT operators, subdivided into 2 groups (A and B) on the basis of tasks performed and average hours/week spent at VDT (25 vs 36), and 190 controls not assigned to VDT. Ocular and musculoskeletal subjective symptoms and objective findings were assessed for all subjects, and the State-Trait Anxiety Inventory (STAI) test was administered. Results. For VDT operators of the 2 groups, the relationship between ocular and musculoskeletal symptoms and findings, working life (P=0.0001) and number of hours spent at the VDT (symptoms P=0.001 and P=0.0001; findings P=0.002 and P=0.007), was significant. Group B VDT operators showed significantly higher state anxiety (S-anxiety) levels vs those in Group A and controls (P=0.001); trait anxiety (T-anxiety) was significantly higher in Group B and controls vs Group A (P=0.001 and P=0.03). Conclusions. Our results confirm the literature data about musculoskeletal and visual disorders and, as for anxiety, seem to denote a higher relevance of factors related to labor organization vs VDT use per se

Exposure to urban stressor and effects on free testosterone in female workers

Background: The aim of the study is to evaluate if occupational exposure to chemical, physical and psycho-social urban stressor could cause alterations in plasma free testosterone (T) levels and related diseases in female traffic police vs. control group. Patients and methods: The research was carried out on initial sample of 468 female Municipal Police employees (209 traffic police and 259 controls). After excluding the principal confounding factors, traffic police were matched with controls by age, working life, menstrual cycle day, BMI, drinking habit, cigarette smoking habit, liquorice and soy intake in diet, habitual consumption of Italian coffee. There were 96 female traffic police and 96 controls included in the study. Results: T mean levels were significantly higher in female traffic police compared to controls (p = 0.000). The distribution of T values in traffic police and in controls was significant (p = 0.000). No significant differences were found comparing the percentage in traffic police and controls concerning dystocial, premature and post-term birth. An increase in mental health disorders was found in traffic police compared to controls but the difference was not significant. Conclusion: The increase in T plasma levels observed in traffic police vs. controls can be due to a chronic working exposure to low doses of environmental chemical urban stressor. According to our previous researches T could be used as an early biological marker even before the onset of the related disorders. (C) 2008 Elsevier B.V. All rights reserved

Exposure to solvents in health care workers: assessment of the hepatic effects.

The use of organic solvents has been linked to pathologies of different apparatuses. The purpose of this study is to analyze the liver damage induced by organic solvents. We analyzed 556 workers, 278 exposed to organic solvents (group 1) and 278 not exposed to organic solvents (group 2). The exposed group was further divided into 2 subgroups: group 1A (139 workers exposed to considerable doses) and group 1B (139 workers exposed to negligible doses). Mean and standard deviation of some liver parameters was calculated. Statistically significant differences between the liver parameters in the different groups and subgroups were detected using the t-test. Multiple linear regression models were used to examine the associations between laboratory parameters and the independent variable. The data so far obtained showed the existence of statistically significant differences with regard to the total protein, total bilirubin, transaminase GOT and GPT, Gamma Glutamyl Transferase (gamma-GT). Our results confirm that exposure to solvents can alter some liver parameters. The blood tests we used can be useful tool for the assessment of the actual occupational hazards and to verify the effectiveness of the measures taken for the prevention and protection