Rock mass characterization by UAV and close-range photogrammetry: A multiscale approach applied along the vallone dell’elva road (Italy)

Geostructural rock mass surveys and the collection of data related to discontinues provide the basis for the characterization of rock masses and the study of their stability conditions. This paper describes a multiscale approach that was carried out using both non-contact techniques and traditional support techniques to survey certain geometrical features of discontinuities, such as their orientation, spacing, and useful persistence. This information is useful in identifying the possible kinematics and stability conditions. These techniques are extremely useful in the case study of the Elva valley road (Northern Italy), in which instability phenomena are spread across 9 km in an overhanging rocky mass. A multiscale approach was applied, obtaining digital surface models (DSMs) at three different scales: large-scale DSM of the entire road, a medium-scale DSM to assess portions of the slope, and a small-scale DSM to assess single discontinuities. The georeferenced point cloud and consequent DSMs of the slopes were obtained using an unmanned aerial vehicle (UAV) and terrestrial photogrammetric technique, allowing topographic and rapid traditional geostructural surveys. This technique allowed us to take measurements along the entire road, obtaining geometrical data for the discontinuities that are statistically representative of the rock mass and useful in defining the possible kinematic mechanisms and volumes of potentially detachable blocks. The main purpose of this study was to analyse how the geostructural features of a rock mass can affect the stability slope conditions at different scales in order to identify road sectors susceptible to different potential failure mechanisms using only kinematic analysis

Risk of hospitalization for heart failure in patients with type 2 diabetes newly treated with DPP-4 inhibitors or other oral glucose-lowering medications: A retrospective registry study on 127,555 patients from the Nationwide OsMed Health-DB Database

Aims Oral glucose-lowering medications are associated with excess risk of heart failure (HF). Given the absence of comparative data among drug classes, we performed a retrospective study in 32 Health Services of 16 Italian regions accounting for a population of 18 million individuals, to assess the association between HF risk and use of sulphonylureas, DPP-4i, and glitazones. Methods and results We extracted data on patients with type 2 diabetes who initiated treatment with DPP-4i, thiazolidinediones, or sulphonylureas alone or in combination with metformin during an accrual time of 2 years. The endpoint was hospitalization for HF (HHF) occurring after the first 6 months of therapy, and the observation was extended for up to 4 years. A total of 127 555 patients were included, of whom 14.3% were on DPP-4i, 72.5% on sulphonylurea, 13.2% on thiazolidinediones, with average 70.7% being on metformin as combination therapy. Patients in the three groups differed significantly for baseline characteristics: age, sex, Charlson index, concurrent medications, and previous cardiovascular events. During an average 2.6-year follow-up, after adjusting for measured confounders, use of DPP-4i was associated with a reduced risk of HHF compared with sulphonylureas [hazard ratio (HR) 0.78; 95% confidence interval (CI) 0.62-0.97; P = 0.026]. After propensity matching, the analysis was restricted to 39 465 patients, and the use of DPP-4i was still associated with a lower risk of HHF (HR 0.70; 95% CI 0.52-0.94; P = 0.018). Conclusion In a very large observational study, the use of DPP-4i was associated with a reduced risk of HHF when compared with sulphonylureas

Can we improve outcome of congenital diaphragmatic hernia?

This review gives an overview of the disease spectrum of congenital diaphragmatic hernia (CDH). Etiological factors, prenatal predictors of survival, new treatment strategies and long-term morbidity are described. Early recognition of problems and improvement of treatment strategies in CDH patients may increase survival and prevent secondary morbidity. Multidisciplinary healthcare is necessary to improve healthcare for CDH patients. Absence of international therapy guidelines, lack of evidence of many therapeutic modalities and the relative low number of CDH patients calls for cooperation between centers with an expertise in the treatment of CDH patients. The international CDH Euro-Consortium is an example of such a collaborative network, which enhances exchange of knowledge, future research and development of treatment protocols

Reconfigurable Multi-Three-Phase Drive for Naval Rim-Driven Propulsion System

Multiphase drives are the subject of great interest for the transportation electrification. Multi-three-phase machines are used with modular three-phase converters to obtain a redundant structure and their great advantage is the fault-tolerance capability. Starting from a symmetrical multi-three-phase machine, a reconfigurable architecture drive can be obtained. The main characteristic of a reconfigurable architecture is the ability to change the winding configuration to better match the operating point, specifically the machine speed. The main advantage of this architecture is the capability of reducing the number of active converters when the machine operates at low speed, thus reducing total converter power losses. However, system complexity increases, since reconfiguration cells are needed to interconnect the winding sets. The proposed reconfigurable multi-three-phase drive architecture exhibits two main benefits at low speed operation: increased efficiency and reduced phase current ripple for a given switching frequency. The reconfigurable architecture was assessed by means of analytical as well as numerical simulations, and the benefits obtainable at low speed operation were also demonstrated experimentally on a reduced scale prototype, capable of 'on the fly' reconfiguration without stopping the machine

PMSM-Model-Based Sensorless Control of Hybrid Stepper Motors: Performance and Robustness to Parameters Dispersion

Extended Kalman Filters (EKFs), Phase Locked Loops (PLLs), and Stator Flux Observers (SFOs) are widely used for sensorless control of Permanent Magnet Synchronous Motors (PMSMs) drives. Their use (in their most advanced version) is here extended, on the basis of model analogies and suitably-guaranteed closed loop stability properties, to the sensorless speed regulation control of Hybrid Stepper Motors (HSMs), in which position and speed sensors are not employed to reduce costs and increase robustness with respect to high temperature and high-vibration environments. Both realistic simulations and experimental results demonstrate the feasibility of the proposed methods in terms of closed-loop performance and robustness to parameters mismatch

Stator Flux Observer for the Sensorless Speed Control of Synchronous Machines with Uncertain Torque Constant

In this paper, a recently designed adaptive stator flux observer (SFO), which provides estimates of rotor position and torque constant for surface mounted permanent magnet synchronous machines (PMSMs), is included in a speed sensorless control. Simulations and experimental results are carried out in order to evaluate the robustness of the whole control architecture with respect to uncertainties in the electrical parameters of the motor, as well as to the mismatch between the actual stator voltages imposed to the PMSM and the ones used for the observer, especially when low speeds are involved

Ground leakage current in PV three-phase current source inverter topologies

Current source inverter (CSI) is a family of power converters which has been recently investigated for photovoltaic power conversion in grid-tied operation, due to the inherent boost capability and ease of control. This paper assess Photovoltaic three-phase Current Source Inverters by two different CSI topologies and space vector modulation commutation strategies. Different CSI solutions are therefore analyzed by means of numerical simulations and the results are compared in terms of ground leakage current and THD of the injected grid currents. Extensive simulation results show that the CSI7 topology can improve the common mode performance while at the same time increasing the efficiency of the conventional CSI, at the price of a negligible added complexity

Retrospective study of 111 cases of congenital diaphragmatic hernia treated with early high-frequency oscillatory ventilation and presurgical stabilization

Background: The prognosis of babies with congenital diaphragmatic hernia (CDH) remains unsatisfactory despite recent advances in medical and surgical treatment. Most authors agree that the best way to improve outcomes for this disease is to focus on pulmonary hypoplasia and persistent pulmonary hypertension (PPH), the 2 most unfavorable prognostic factors for patient survival. However, controversy remains regarding the best treatment of CDH. In the past decade, several institutions have developed treatment protocols that include high-frequency oscillatory ventilation (HFOV), preoperative stabilization, and no thoracic drain. This strategy is 1 of several "gentle ventilation" strategies. We describe our 10-year experience in treating a cohort of 111 infants with CDH managed with this "gentle ventilation" strategy. Methods: From October 1994 to June 2005, 111 babies with CDH were treated at our institution with HFOV. Babies progressed to inhaled nitric oxide and extracorporeal membrane oxygenation if severe PPH persisted. After a period of preoperative stabilization, surgery was performed via an abdominal approach. In case of large defects or diaphragmatic agenesis, a prosthetic patch was used. No thoracic drain was left in place at the end of surgery. The charts of all babies were reviewed. General characteristics, respiratory management, as well as perioperative and postoperative data were analyzed and correlated with survival. Predicted and actual survival rates in high-, intermediate-, and low-risk groups were analyzed on the basis of the equation described by the Congenital Diaphragmatic Hernia Study Group in 2001. Results: The overall survival rate in our group of patients with CDH was 69.4% regardless of side of the defect. Incidence of a prenatal diagnosis before the 25th gestational week, coexistence of severe congenital heart disease (overall incidence, 5.4%), or other major associated anomalies, as well as the presence of a diaphragmatic agenesis were significantly higher in nonsurvivors. Thirty-six had severe PPH, of which 26 (76.5% of nonsurviving patients) died. Survivors and nonsurvivors had significant differences in blood gas analysis and respiratory management data recorded before and after the diaphragmatic correction. Ninety-nine (89%) patients underwent correction of the diaphragmatic defect. A patch was used in 44 (44%) patients and 15 of them died (survivors, 37.7%; nonsurvivors, 68.2%; P = .0111). Six (43%) of 14 patients with a preoperative pneumothorax (survivors, 10.3%; nonsurvivors, 27.3%; P > .05) and 7 (58%) of 12 patients with a postoperative pneumothorax needing a thoracic drain (survivors, 6.5%; nonsurvivors, 31.8%; P = .0013) died. In all cases, pneumothorax was ipsilateral. Two patients required oxygen therapy at discharge. The predicted survival rate was 69%; there was no difference between predicted and actual overall survival as well as between predicted and actual survival in low-risk (predicted survival rate, >66%), intermediate-risk (predicted survival rate, 34%-66%), and high-risk (predicted survival rate, <33%) groups. Conclusions: The CDH treatment strategy that includes HFOV, preoperative stabilization and no thoracic drain ensures survival with minimal pulmonary morbidity (low rate of pulmonary infections and low rate of patients requiring oxygen at home) in most affected babies. Persistent pulmonary hypertension has been the most challenging factor that ultimately determined the final outcome, and availability of new vasoactive drugs is mandatory to ameliorate the prognosis especially in high-risk patients. Meanwhile, survival comparisons of low-, intermediate-, and high-risk groups between institutions using different protocols will allow the identification of the best strategy for CDH management. © 2007 Elsevier Inc. All rights reserved