Numerical study on active and passive trailing edge morphing applied to a multi-MW wind turbine section

A progressive increasing in turbine dimension has characterized the technological development in offshore wind energy utilization. This aspect reflects on the growing in blade length and weight. For very large turbines, the standard control systems may not be optimal to give the best performance and the best vibratory load damping, keeping the condition of maximum energy production. For this reason, some new solutions have been proposed in research. One of these is the possibility of morphs the blade surface in an active way (increasing the performance in low wind region) or passive (load reduction) way. In this work, we present a numerical study on the active and passive trailing edge morphing, applied to large wind turbines. In particular, the study focuses on the aerodynamic response of a midspan blade section, in terms of fluid structure interaction (FSI) and driven surface deformation. We test the active system in a simple start-up procedure and the passive system in a power production with turbulent wind conditions, that is, two situations in which we expect these systems could improve the performance. All the computations are carried out with a FSI code, which couples a 2D-CFD solver, a moving mesh solver (both implemented in OpenFOAM library) and a FEM solver. We evaluate all the boundary conditions to apply in the section problem by simulating the 5MW NREL wind turbine with the NREL CAE-tools developed for wind turbine simulation

Numerical study on active and passive trailing edge morphing applied to a multi-MW wind turbine section

A progressive increasing in turbine dimension has characterized the technological evelopment in offshore wind energy utilization. This aspect reflects on the growing in blade length and weight. For very large turbines, the standard control systems may not be optimal to give the best performance and the best vibratory load damping, keeping the condition of maximum energy production. For this reason, some new solutions have been proposed in research. One of these is the possibility of morphs the blade surface in an active way (increasing the performance in low wind region) or passive (load reduction) way. In this work, we present a numerical study on the active and passive trailing edge morphing, applied to large wind turbines. In particular, the study focuses on the aerodynamic response of a midspan blade section, in terms of fluid structure interaction (FSI) and driven surface deformation. We test the active system in a simple start-up procedure and the passive system in a power production with turbulent wind conditions, that is, two situations in which we expect these systems could improve the performance. All the computations are carried out with a FSI code, which couples a 2D-CFD solver, a moving mesh solver (both implemented in OpenFOAM library) and a FEM solver. We evaluate all the boundary conditions to apply in the section problem by simulating the 5MW NREL wind turbine with the NREL CAE-tools developed for wind turbine simulation

Cytomegalovirus Replicon-Based Regulation of Gene Expression In Vitro and In Vivo

There is increasing evidence for a connection between DNA replication and the expression of adjacent genes. Therefore, this study addressed the question of whether a herpesvirus origin of replication can be used to activate or increase the expression of adjacent genes. Cell lines carrying an episomal vector, in which reporter genes are linked to the murine cytomegalovirus (MCMV) origin of lytic replication (oriLyt), were constructed. Reporter gene expression was silenced by a histone-deacetylase-dependent mechanism, but was resolved upon lytic infection with MCMV. Replication of the episome was observed subsequent to infection, leading to the induction of gene expression by more than 1000-fold. oriLyt-based regulation thus provided a unique opportunity for virus-induced conditional gene expression without the need for an additional induction mechanism. This principle was exploited to show effective late trans-complementation of the toxic viral protein M50 and the glycoprotein gO of MCMV. Moreover, the application of this principle for intracellular immunization against herpesvirus infection was demonstrated. The results of the present study show that viral infection specifically activated the expression of a dominant-negative transgene, which inhibited viral growth. This conditional system was operative in explant cultures of transgenic mice, but not in vivo. Several applications are discussed

Numerical study on active and passive trailing edge morphing applied to a multi-MW wind turbine section

A progressive increasing in turbine dimension has characterized the technological development in offshore wind energy utilization. This aspect reflects on the growing in blade length and weight. For very large turbines, the standard control systems may not be optimal to give the best performance and the best vibratory load damping, keeping the condition of maximum energy production. For this reason, some new solutions have been proposed in research. One of these is the possibility of morphs the blade surface in an active way (increasing the performance in low wind region) or passive (load reduction) way. In this work, we present a numerical study on the active and passive trailing edge morphing, applied to large wind turbines. In particular, the study focuses on the aerodynamic response of a midspan blade section, in terms of fluid structure interaction (FSI) and driven surface deformation. We test the active system in a simple start-up procedure and the passive system in a power production with turbulent wind conditions, that is, two situations in which we expect these systems could improve the performance. All the computations are carried out with a FSI code, which couples a 2D-CFD solver, a moving mesh solver (both implemented in OpenFOAM library) and a FEM solver. We evaluate all the boundary conditions to apply in the section problem by simulating the 5MW NREL wind turbine with the NREL CAE-tools developed for wind turbine simulation

General anesthesia impairs muscle microvascular compliance

Introduction Drugs used to induce and maintain general anesthesia have deep effects on the cardiovascular system. To our knowledge there are no studies investigating microvascular compliance during general anesthesia with a noninvasive approach based on near-infrared spectroscopy (NIRS) technology. Methods We randomized 36 healthy subjects undergoing maxillofacial surgery to receive general anesthesia with a sevofluorane–remifentanil (Group S) or a propofol–remifentanil association (Group P). We collected noninvasive measures of hemoglobin concentration from the gastrocnemius muscle of the subjects using a NIRS device (NIMO, NIROX srl, Italy), which performs quantitative assessments of the [HbO2] and [Hb] exploiting precise absorption measurements close to the absorption peak of the water. Data were collected during a series of venous occlusions at different cuff pressures, before and after 30 minutes from induction of general anesthesia. The muscle blood volume and microvascular compliance were obtained with a process previously described elsewhere [1]. Data were analyzed with a one-way analysis of variance test. Results Demographic data of the 36 subjects were similar in both Groups S and P. General anesthesia reduced the heart rate and mean arterial pressure and increased the total muscle blood volume in both groups (Group S: from 2.4 ± 0.9 to 3.2 ± 1.2 ml/ 100 ml; Group P: from 2.4 ± 1.2 to 3.5 ± 1.8 ml/100 ml; P < 0.05). During general anesthesia, despite no differences in muscle blood volume between the two groups, sevofluorane– remifentanil significantly decreased microvascular compliance (from 0.15 ± 0.08 to 0.09 ± 0.04 ml/mmHg/100 ml; P = 0.001) whereas propofol–remifentanil did not (from 0.15 ± 0.08 to 0.16 ± 0.11 ml/mmHg/100 ml; P = 0.39). Conclusion General anesthesia affects the microvascular bed of skeletal muscle. An association between opioid and ipnotic agents increases the muscle blood volume, whereas microvascular compliance is reduced only by the sevofluorane–remifentanil association. Reference 1. De Blasi RA, Palmisani S, Alampi D, et al.: Microvascular dysfunction and skeletal muscle oxygenation assessed by phase modulation near-infrared spectroscopy in patients with septic shock. Intensive Care Med 2005, 31:1661-1668

The sensitivity of RNA polymerases I and II from Novikoff hepatoma (N1S1) cells to 3′-deoxyadenosine 5′-triphosphate

The synthesis of ribosomal precursor RNA in Novikoff hepatoma (NISI) cells is very sensitive to cordycepin (3′-dA). The synthesis of hnRNA, however, is resistant to inhibition by concentrations of 3′-dA that completely block the synthesis of 45S ribosomal RNA precursor. We have examined the RNA polymerases present in these cultured cells with regard to their sensitivity to cordycepin 5′-triphosphate (3′-dATP) in an effort to explain the differential inhibition of RNA synthesis observed in vivo. RNA polymerases I and II were characterized on the basis of their chromatographic behavior on DEAE-Sephadex, as well as the response of their enzymatic activities to ionic strength, the divalent metal ions Mn2$and Mg2$, and the toxin α-amanitin. For both enzymes the inhibition of in vitro RNA synthesis by 3′- dATP was competitive for ATP. The Km values for ATP and the Ki values for 3′-dATP for the two enzymes were quite similar. RNA polymerase II, the enzyme presumed responsible for hnRNA synthesis, was actually slightly more sensitive to 3′-dATP than RNA polymerase I, the enzyme presumed responsible for ribosomal precursor RNA synthesis. Similar data were obtained when the RNA polymerases were assayed in isolated nuclei. These results indicate that the differential inhibition of RNA synthesis caused by 3′-dA in vivo cannot be simply explained by differential sensitivity of RNA polymerases I and II to 3′-dATP