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Power Quality (PQ) conditioning in LV distribution networks is an increasing concern within modern power system and Smart Grid systems. Several phenomena have classified in standard, among those, voltage sags and rms voltage drifts have been reported as most significant and frequent ones in both MV and LV distribution systems. Several solutions have been proposed to deal with these voltage disturbances. Dynamic Voltage Restorer (DVR) and Dynamic Voltage Conditioner (DVC) are the most promising solutions. Controlling these series connected devices is a challenge especially in single-phase schema which is an appreciated solution for Distribution System Operator (DSO). This paper investigates difference control strategies for single-phase DVC system. Control methods are explained in detail and MATLAB based simulation results are reported. Investigated control methods performance dealing with example voltage drop event have been reported.

Distributed Energy Resources (DER) connected to distribution grids through static power converters may have major impacts on Power Quality (PQ). For this reason, power converters used as Universal Compensators (UC) are gaining more and more interest. This paper describes the design, modeling and study of a shunt static compensator for Low Voltage distribution grids. The proposed device can be used for interfacing Distributed Generators (DG) or Energy Storage Systems (ESS) to the grid and can be connected close to disturbing loads. This device can compensate harmonic currents, reactive power and unbalances of disturbing loads, and it can also supply sensitive loads in island operation. Performances of the proposed device, with different control schemes and with different harmonic compensation strategies, are assessed through Control Hardware in the Loop (CHIL) Real Time simulations.

An 8-year-old intact male dwarf rabbit ( Oryctolagus cuniculus ) was presented with a 2-month history of unilateral scrotal swelling. The external physical examination of the rabbit patient confirmed the severe, unilateral, fluid-filled scrotal distention. Radiographic images of the effected scrotum revealed a soft tissue swelling in the area of the left testicle, and the absence of the urinary bladder in the caudal abdomen. Ultrasonography verified the presence of a fluid-filled mass in the scrotum, enveloping the left testicle. A fine-needle aspiration of the scrotal mass yielded urine, thus a diagnosis of a nonreducible herniation of the urinary bladder into the scrotum was made. An inguinal herniorrhaphy was performed, and the bladder was successfully reduced into the abdominal cavity. A bilateral routine castration and left scrotal ablation were also performed. Two months after surgery no recurrence was noted, and the patient had normal urinary function. Inguino-scrotal bladder herniation is rare in both humans and animals. Male rabbits are predisposed to inguinal and scrotal hernias because their inguinal rings remain open throughout life. Herniation of the urinary bladder should be considered as a differential diagnosis when intact male rabbits are presented with unilateral scrotal swelling.

The presence of Distributed Generation (DG) in t he distribution network is increasing and represents one of the most important research areas. Several reasons have forced this increase like the possibility to use renewable resources reducing the fossil fuels use with environmental and energy benefits. The paper deals with the results of a study performed by RSE, in the frame of the Research Fund for the Italian Electrical System, focused on the behaviour during voltage dips of a "DG system", consisting in a Photovoltaic generator (PV) connected to the network with three phase Voltage Source Inverter (VSI).

The paper deals with a recent measurement improvement introduced into the Italian power quality monitoring system, concerning voltage dips detection and their proper evaluation in the presence of voltage transformer VT saturation phenomena. Saturation effects, essentially on network operated with isolated neutral, can give origin to "false" voltage dips, which can affect the on-line voltage monitoring during a few specific events (i.e. single line-to-ground faults). The "false dip" problem, on the other hand, can be considered negligible in compensated neutral networks. A new criterion has been developed in cooperation with the Polytechnic of Turin, based on the detection of a second harmonic component in the measured voltages, which, once provided with the proper setting parameters, can succeed in identifying "false" dips. The criterion effectiveness has been evaluated on field. The major advantage of the filter implementation in the monitoring system is that, from now on, network operated with isolated neutral could be considered quite similar to those operated with neutral compensation from the point of view of voltage dip performance.

The voltage dip and the sudden electrical energy interruption are, probably, the most important dist urbances of the power quality in the electrical system. Several technical solutions exist to mitigate volta ge dips, respectively at plant or system level as for exampl e: • the installation of Custom Power (CUSPO) for a single customer; • the Premium Power Park (PPP) for a group of customers. According to the PPP concept, the tenants of an ind ustrial or commercial office park would be provided with a guaranteed level of electrical service quality made possible b y Custom Power devices, such as the Dynamic Voltage Restorer (DVR), the Distribution Static Compensator (DSTATCOM - Distribution STATCOM), the medium voltage Static Transfer Switch (STS). The paper summarizes the Premium Power Park idea and a possible configuration of it, studied by ERSE, inclu ding the system aspects and the analysis of the combined ope ration or interaction of the Custom Power.

To evaluate whether early treatment with inhaled nitric oxide (iNO) will prevent newborns with moderate respiratory failure from developing severe hypoxemic respiratory failure (oxygenation index (OI)or=40).A total of 56 newborns with moderate respiratory failure (OI between 10 and 30) were randomized before 48 h after birth to early treatment with 20 p.p.m. of iNO (Early iNO group, n=28) or conventional mechanical ventilation with FiO(2) 1.0 (Control group, n=28). Infants received iNO and/or high-frequency oscillatory ventilation (HFOV) if they developed an OI40.7 of 28 early iNO patients (25%) compared to 17 of 28 control patients (61%) developed an OI40 (P0.05). In the Early iNO group mean OI significantly decreased from 22 (baseline) to 19 at 4 h (P0.05) and remained lower over time: 19 (12 h), 18 (24 h) and 16 at 48 h. In contrast, OI increased in the Control group and remained significantly higher than the Early iNO group during the first 48 h of study: 22 (baseline), 29, 35, 32 and 23 at 4, 12, 24 and 48 h, respectively (P0.01). Of 17, 6 control patients who developed an OI40 were successfully treated with iNO. Nine of the remaining eleven control patients and six of seven Early iNO patients who had an OI40 despite use of iNO responded with the addition of HFOV. One patient of the Early iNO group and two of the Control group died. Median (range) duration of oxygen therapy was significantly shorter in the Early iNO group: 11.5 (5 to 90) days compared to 18 (6 to 142) days of the Control group (P0.03).Early use of iNO in newborns with moderate respiratory failure improves oxygenation and decreases the probability of developing severe hypoxemic respiratory failure.

This paper considers the possibility to connect two medium voltage primary distribution grids through a DC connection realized by two AD/DC converters in back-to-back configuration. In particular, after a description of the whole system, the effects of a bolted or non-bolted DC fault are analyzed. Then, an active current limiter is proposed to limit the fault currents and keep the controllability of the system. Such a system is then modeled and studied through many simulations that confirm the effectiveness of the proposed current limiter.

This paper deals with the proposal of a connection to form closed-loop or meshes inside one or more medium voltage primary distribution networks. The main idea consists in realizing this connection through a suitable tie converter constituted by two AC/DC converters in back-to-back configuration. In this way, it is possible to control the power flows between two lines or two different grids keeping the radial structure of the system. This can be useful in presence of distributed generation to share the power among many loads connected to different distribution lines. In the paper the proposed system is analyzed, simulated and discussed both in steady state condition and during faults coming from the MV primary distribution network.

The simulation of the unsteady free-surface flow on infiltrating surfaces has many hydrological applications, including the study of overland flow, soil erosion and conservation, surface irrigation and contaminant transportation. The surface runoff is strictly connected to the infiltration through the soil surface; so, an independent simulation of the two processes, although very often adopted, may be unrealistic. This paper presents a mathematical model for simulating these interdependent surface and subsurface processes. The model is based on the two-dimensional shallow water equations, coupled with the one-dimensional Richards equation. These equations are integrated jointly, following the MacCormack scheme, which is an explicit, finite-difference scheme, accurate to the second order. The model can simulate initially dry surface conditions and variable initial soil water content, and can deal with space-variable characteristics (slope, roughness and soil hydraulic properties). The accuracy of the model is tested by comparing its results with analytical solutions and with experimental data. Finally, a numerical experiment carried out on a simple hypothetical catchment, both using the complete model and a simplified version, in which the Richards equation and the shallow water equations are solved in cascade, is discussed.

The objective of the GREAT-ER project is to develop and validate a powerful and accurate aquatic chemical exposure prediction tool for use within the EU environmental risk assessment schemes. Current techniques to estimate regional PECs use a generic multimedia `unit world' approach and do not account for spatial and temporal variability in landscape characteristics, river flows and/or chemical emissions. Hence, the results are merely applicable on a generic screening level since these models do not offer a realistic prediction of actual steady-state background concentrations. In addition, the default EU generic regional environment (EU Technical Guidance Documents, 1996) only allows treatment for 70% of the waste water mass loading, leaving 30% of mass loading to this generic region untreated. A new database, model and software system will be developed to calculate the distribution of predicted environmental concentrations (PEC), both in space and time, of down the drain chemicals in European surface waters on a river and catchment area level. Data on dissolved oxygen, biological oxygen demand and ammonia will also be used to assess water quality and to provide data for calibration and validation. The system will use Geographical Information Systems (GIS) for data storage and visualization, combined with simple mathematical models for prediction of chemical fate. Hydrological databases and models will be used to determine flow and dilution data. This refined exposure assessment tool should greatly enhance the accuracy of current local and regional exposure estimation methods. The new exposure assessment methodology will integrate specific environmental information and be worked out in a geographically-referenced framework, ultimately on a pan-European scale. This research project is carried out on behalf of ECETOC, and sponsored by the Environmental Risk Assessment Steering Committee (ERASM) of the Association Internationale de la Savonnerie, de la Detergence et des Produits d'Entretien (A.I.S.E.) and the Comite Europeen de Agents de Surface et Intermediares Organiques (CESIO) in cooperation with the UK Environment Agency.

The paper presents the study performed to evaluate the interactions between Distributed Generation and the network during voltage dips. In particular, international grid codes that require Distributed Generation to stay connected during network faults have been considered. In the study a PhotoVoltaic power system (PV) and a typical wind power system based upon a Permanent Magnet Synchronous Generator (PMSG) connected together to a Medium Voltage (MV) distribution network have been simulated. Fault Ride Through (FRT) requirements that provide the inverter should supply a controlled current over q-axis during a balanced voltage dip have been considered.

The paper deals with the results of a study performed by RSE, in the frame of the Research Fund for the Italian Electrical System, and Politecnico di Milano focused on the evaluation of the harmonic impact in the distribution networks caused by the Distributed Generation, generally connected through Voltage Source Inverter (VSI). In particular the two-level three phase Pulse Width Modulation (PWM) inverter configuration has been investigated and the Fourier series analysis of the output voltage, has been evaluated. To reduce the harmonic impact of the inverters connected at the Point of Common Coupling (PCC) the interleaved inverters configuration has also been analysed.

The basic concept of a Premium Power Park (PPP) is to ensure better power supply quality level than the standard one offered by the distribution system and also diversified levels depending on customers' needs, thanks to the use of different kind of Custom Power devices (CUSPO). The CUSPO are power electronics devices that are able to compensate voltage dips on critical loads dynamically and voltage variations due to disturbing loads. The efficiency of these devices depends on the efficiency of the control technique implemented in the inverter. The paper deals with the simulations of a possible configuration of Premium Power Park (PPP), studied by ERSE in the frame of the Research Fund for the Italian Electrical System, focusing on a D-STATCOM control system and operating condition in the studied PPP.

In 2005 the Italian Regulatory Authority for Electricity and Gas (Autorita per l'Energia Elettrica e il Gas, AEEG) promoted a Power Quality (PQ) monitoring campaign carried out by means of the Italian MV power quality monitoring system named QuEEN realized by ERSE, in the framework of the Research Fund for the Italian Electrical System. Right from the start the main objectives of the campaign were to provide a sound knowledge of the actual performance of MV distribution networks in terms of PQ parameters and to give a useful support to Standardization and Regulation activities. The paper is focused on possible site and system indices suitable to characterize the MV network voltage dip performance at both national and macro area level. The proposed indices have been evaluated on the base of the QuEEN data collected up to now and their trends will be used to investigate about possible regulatory strategies.

Initially characteristic features of program are presented. Consequently, the use of the package in decision making processes is briefly discussed. In the following section data requirements are provided. The last section of the paper is focused on application of the program in the study on operation of multiple reservoir system of the Zambezi river in southern Africa.

The paper presents the basic concepts of an interactive PC-AT based software package IRIS for simulation analysis of various development planning and management policy options in large river systems. IRIS package together with multiobjective optimization was used to analyse problems of hydropower generation and operation of reservoirs in the Zambezi river basin. Problems of water management in the basin were discussed and approaches to solve formulated decision problem presented. Combined use of optimization and simulation techniques is discussed: proposed optimal solution of the problem was analysed in the framework of IRIS to detect the impact of modification of this solution on the system's performances, including secondary objectives. Finally, conclusions on the applicability of IRIS package are drawn..

The role of imaging in the management of maxillofacial trauma is to describe anatomical lesions and to detect complications and associated injuries. Plain films are still useful for minimal trauma, but CT-scan is the gold standard for complex trauma. Helical CT and multidetector row CT simplify the emergency imaging of horizontal struts (skull base, orbital floor, alveolar ridge and palate). The diagnosis, and sometimes the treatment of complications may require CT cisternography, MRI and angiography.review mechanisms and classification of paranasal sinuses trauma; present the imaging techniques with special emphasis on CT; describe paranasal sinuses trauma features and pseudo-fracture patterns; describe complications and associated injuries.

The objectives of the present report were to give a baseline picture of hepatitis B notification incidence rates in children before the campaign of mass vaccination for newborns and adolescents (12-13 years old), and to study the role of different risk factors. Data from a specific national surveillance system of acute viral hepatitis (SEIEVA, Sistema Epidemiologico Integrato dell'Epatite Virale Acuta) were used and acute hepatitis B cases were compared to acute hepatitis A patients with the case-control study method to estimate the associations with the considered risk factors. Since the system began, one hundred and sixty-three local health departments have joined SEIEVA covering 30% of the Italian population. The incidence of acute hepatitis B notifications among 0-14 aged children was 9 per 100,000 in 1985 and 1 per 100,000 in 1990. Such decline in incidence was observed in both the North and the South of Italy. Surgical interventions, dental therapy and household contacts with a HBsAg chronic carrier were found to be associated with acute hepatitis B. The point estimate of the odds ratio was 10 for the latter risk factor. Other preventive measures in addition to vaccination are needed to control the risk of hepatitis B infection and other parenteral diseases due to surgical intervention and dental therapy.

This paper focuses on a way of managing a single-reservoir, multipurpose water resource system. Indeed, from a conceptual point of view, the totality of the ideas expressed here can be extended to a multi- reservoir system. The rationale of the restriction is to simplify the theoretical aspects and to match them with the prototype Decision Support System (DSS) for the management of a single reservoir system presented in the paper. Lake Como serves as an example case study.

Reservoir operation is a process of making tradeoffs among conflicting objectives on the basis of different performance criteria. In particular the manager may be interested in long term efficiency (stochastic approach) or in avoiding severe failures in critical hydro-logical conditions (risk-averse approach). In this paper it is shown that, in the case of lake Como (a regulated lake in Northern Italy), the choice of the optimization criterion strongly affects the solution of the multiobjective optimal control problem of the lake, leading to substantially different operating rules. It is also shown, however, that the two approaches can be combined, thus achieving highly satisfactory performances with respect to both criteria.

Two analogues of PGI2, FCE 21258 (5E-13,14-didehydro-carboprostacyclin) and FCE 21292 (5E-13,14-didehydro-20-methyl-carboprostacyclin) have been evaluated in comparison with PGI2 in different in vitro and in vivo screening tests. The rank order of potency was PGI2 greater than FCE 21292 greater than FCE 21258 in the following tests: potentiation of bradykinin-induced increased plasma protein extravasation in the guinea pig skin, inhibition of guinea pig platelet aggregation in vivo where the duration of action of FCE 21292 was longer than that of PGI2, lowering of mean systemic arterial pressure in conscious normotensive and spontaneously hypertensive rats and inhibition of rabbit platelet aggregation in vitro. In the relaxation of bovine coronary artery in vitro the rank order of potency was FCE 21292 greater than PGI2 greater than FCE 21258.

Summary The efficacy of PGI 2 and 20-methyl-PGI 2 in preventing aspecifically induced bronchoconstriction was evaluated in a single-blind cross-over study in 9 asthmatic patients. PGI 2 and its 20-methyl-isomer were given by inhalation in doses ranging from 250 μg (in women) to 500 μg (in men). Ultrasonic H 2 O mist (6 patients) and physical exercise (cycling) were used as bronchial stimulant agents. Both prostacyclins gave an excellent degree of protection but had no direct bronchodilator effect. An increase in heart rate was observed in almost all patients immediately after inhalation of PGI 2 and 20-methyl-PGI 2 , but this effect was particularly evident in women in whom a significant decrease in diastolic pressure was noted too.

The preparation of 125I-labelled tracer for digoxin radioimmunoassay (125I monoiodinated 3-succinyl digoxigenin-1-tyrosine) is described, and its performance in radioimmunoassay of plasma samples is compared with that obtained with tritiated digoxin. The accuracy levels were assessed through the evaluation of different potential sources of systematic errors, such as interference from digoxin-related molecules and plasma proteins and methodological artefacts possibly associated with the immunocomplex instability, and through a series of checks including the recovery and parallelism tests and the correspondence of results obtained with the two tracers. The slope and the repeatability with time of the calibration curves and the spread of replicate estimates were taken into consideration to assess the assay precision. An essential equivalence in terms of reliability of measurement was proved for the two methodological variants, so that practical aspects and economic factors, remain the main criteria to evaluate the relative merits: from this point of view, the advantages of using 125I-labelled tracer, as an alternative to tritiated digoxin, are discussed.

The effects of methodological variables on the quality of insulin radioimmunoassay were studied, including: (a) the individual characteristics of antiserum and tracer preparations; (b) the incubation modality (non-equilibrium, delayed addition of tracer); (c) the procedure of separation of free from bound antigen (adsorbents and immunoprecipitation); (d) the non-identity of sample and standard solutions as for the protein content. A number of experimental factors were expectedly found to influence the sensitivity of response. Conversely, important effects on assay accuracy were found to be associated only with the double-antibody method used and with non-identity of samples and standards. The results of investigations on the possible sources of the systematic errors involved and on their relevance in routine measurements are reported and discussed.

The biological activities of 8,12-diiso-PGE2 (ent-11,15-epi-PGE2), PGE2 and PGF2alpha have been compared in a series of pharmacological preparations intended to differentiate between F and E type of activity. Similar to PGF2alpha but unlike PGE2, 8,12-diiso-PGE2 increased the tone of isolated smooth muscle preparations of guinea pig trachea, guinea pig colonic circular layer, rabbit Fallopian tubes. The stimulation effect of 8,12-diiso-PGE2 and PGF2alpha on visceral smooth muscle was also shown in vivo: the two drugs were in all instances able to increase the miogenic activity and tone of rabbit uterus in situ, while these were depressed by PGE2. 8,12-diiso-PGE2 decreased pulmonary compliance and increased pulmonary vascular resistance in the anaesthetized cat; PGE2 always decreased pulmonary vascular resistance, while leaving pulmonary compliance unaltered. The possibility is suggested that 8,12-diiso-PGE2 acts on PGF receptor in different tissues.

This paper presents two packages designed to solve some of the most common problems involved in the analysis of a river catchment on a personal computer. The main operations performed concern pre-processing of raw meteorological data (to obtain time series of rainfall, snowfall and daily mean temperatures at different elevations), and simulation of the daily runoff from the catchment. Both packages have been developed at the Laboratorio di Informatica Ambientale e Territoriale (LITA) of the Politecnico di Milano, Italy.

Summary The biological activity of four unnatural prostaglandins: ent-11, 15-epi PGE 2 , ent-11-epi PGE 2 . ent-11,15-epi PGF 2α and ent-11,15-epi PGF 2β has been evaluated. These compounds are definitely less active than the natural ones, with the exception of enantio-11,15 epi PGE 2 which, in the rat, in comparison to prostaglandin E 2 (PGE 2 ) is nearly half as potent in inhibiting stress — induced gastric ulcers, almost as potent in decreasing arterial blood pressure and 10 times more potent in contracting isolated uterus “in vitro”, while having very little activity on gastro-intestinal smooth muscle.

Two microanalytical methods for the determination of iodine in material of biological interest were studied: neutron-activation analysis and automated colorimetry (iodide catalysis of the As(III)-Ce(IV) system). The methods were applied to the analysis of samples of water, biological fluids, common salt and solid substances such as tissues, stools and foods. The particular procedures set up and optimized for the different substances with both methods are described and discussed, and the respective advantages in terms of sensitivity, accuracy, precision and speed are compared. The sensitivity and accuracy of both techniques were found to be quite adequate. Automated colorimetry is to be preferred for its precision and operative simplicity, while activation analysis retains full validity as a reference check method.

A series of synthetic analogues of prostacyclin (PGI2) have been compared for their ability to increase the formation of cyclic AMP and to inhibit the aggregation of human platelets, and for relaxation of isolated bovine coronary arteries and lowering of the blood pressure of concious rats. The most active inhibitors of aggregation were derivatives of PGI2 with a triple bond at C14:15. There was good aggreement between the inhibition of platelet aggregation and elevation of cyclic AMP in platelets, and both effects were enhanced by phosphodiesterase inhibitors. The most active compounds of the series were K13415 (14,15-didehydro 20-methyl PGI2), and a carbocyclic analog, FCE21258 (5e-14,15-didehydro carbo PGI2) which were both more active than PGI2 itself. In addition, the carbocyclic compounds were stable at neutral pH. Compounds K13817 (14,15-didehydro 16-methyl PGI2) and FCE21292 (5e-14,15 didehydro 20-methyl carbo PGI2) were similar in activity to PGI2 as platelet inhibitors, but had less vasodilator and depressor activity. The results show considerable differences in the structural specificities of the platelet and vascular activities of PGI2.

Synthesis of alpha-halo-alpha,beta-unsaturated ketones from aldehydes as a synthetic approach to prostaglandins is investigated.

The bronchodilator activity of four analogues of PGE2: 13,14-didehydro-PGE2 (I), 20-methyl-13,14-didehydro-PGE2 (II), 16 S-methyl-13,14-didehydro-PGE2 (III) and 16 R-methyl-13,14-didehydro-PGE2 (IV) was studied in vivo and in vitro. The potency of III and IV when administered by aerosol to conscious guinea pigs was four times that of PGE2 in protecting against histamine-induced convulsion; I and II were less active. Compound III administered by aerosol to anaesthetized guinea pigs was six times more potent than PGE2 in protecting against i.v. histamine-induced increase of intractracheal pressure and the effect was longer-lasting. All the compounds caused relaxation of carbachol-induced tone in isolated guinea pig tracheal strips.

Summary A novel chemical synthesis of nat- and rac-Prostacyclin (PGI 2 ) and 5,6-dihydro-PGI 2 is described. Like PGI 2 , both stable analogs inhibit human platelet aggregation induced by ADP, Arachidonic Acid (AA), Collagen and Adrenaline. In all forms of aggregation, 5,6 α -dihydro-PGI 2 resulted 10 times more potent than 5,6 β -dihydro-PGI 2 . The potency ratio of 5,6 α -dihydro-PGI 2 to PGI 2 was variably estimated between 1:100, in the case of ADP-induced aggregation, and 1:10 in the case of AA-induced aggregation. The availability of stable mimics of PGI 2 should be of considerable value in future studies of this substance and may have therapeutic implications.