Stability Analysis of Open-Loop V/Hz Controlled Asynchronous Machines and Two Novel Mitigation Strategies for Oscillations Suppression

Asynchronous machines are always widely used in most industrial applications due to their reliability, flexibility, and manoeuvrability. To achieve variable speed operations, the quite simple open-loop V/Hz control is largely utilized. Under open-loop V/Hz control, the nonlinear interaction is well known to cause current and torque oscillations while operating at low to medium speeds under light loads. This article presents the stability analysis of induction motors at low\u2013medium frequencies under no-load conditions with the V/Hz control. A system representation in the form of state space is discussed, and the region of instability is plotted against the V/f plane. Two novel and refined methods for the mitigation of oscillations in the region of instability are presented. The two proposed algorithms are finally tested and validated through simulation on an inverter-fed induction motor drive system

Induction Motor Field-Oriented Sensorless Control with Filter and Long Cable

In recent years, part of the efforts of the electric drive researcher has been focused on the study of sensorless control algorithms that allow controlling the machine without a speed measure and with ever-fewer measurement devices. This article proposes a possible solution for the submarine application of an asynchronous motor. The motor is designed to drive a petrol pump at a depth of three thousand meters. The motor is fed by an inverter that is located on an offshore platform, and they are connected through a filter and a cable that is 19.74 km long. In this application, it is not suitable to use a speed measurement device; in fact, at this depth it is important to use as few components as possible, in order to increase the system reliability. A control algorithm that only needs available electrical measures is proposed below

Hashimoto’s encephalopathy in a patient with septal panniculitis: a case report

Hashimoto’s encephalopathy (HE) is an autoimmune form of encephalopathy, associated with autoimmune thyroiditis. Its prevalence is estimated to be 2:100,000. HE is characterized by behavioral changes, mental confusion, dysarthria, ataxia, psychosis, paranoia, convulsions, hallucinations, headache and hyperthermia. Elevated thyroid antibodies are necessary for diagnosis and the disease responds dramatically to glucocorticoid therapy. We describe a patient with HE and panniculitis, an association reported twice in the literature

Analysis and results of the industrial production of the superconducting Nb/Cu cavities for the LEP2 project

For the energy upgrade of the Large Electron Positron Collider at CERN 216 RF superconducting cavities were ordered from three European industrial firms (Ansaldo, Cerca, Siemens/Accel) at the beginning of 1991. These cavities are made of copper (Cu), internally coated with niobium (Nb) according to a procedure developed at CERN. Up to now about 147 of these cavities fulfilling the specifications have been produced. The large-scale statistics available and the use of dedicated analytical and optical inspection techniques shed new light on the relationship between production procedures, niobium film properties and cavity performance. An overview of this subject is presented, together with some significant trends and results

Effect of body condition score, treatment period and month of the previous lambing on the reproductive resumption of melatonin-treated sarda breed sheep during spring

Stakeholders place great emphasis upon rationalizing the management and rearing techniques which are utilized within sheep farms. The present study aimed to investigate factors which may improve the reproductive performance of melatonin-treated Sardinian sheep via a series of three trials. The first trial (n = 100) investigated the effect of melatonin treatment alongside body condition score (BCS), the second trial (n = 150) investigated the effect of treatment alongside the date of treatment (treatment period) and the third trial (n = 150) investigated the effect of treatment alongside the previous lambing of the ewes. The findings indicated that melatonin is an effective tool for anticipating and improving the reproductive activity of in Sarda breed sheep during the springtime. Furthermore, to obtain optional results, melatonin implantation should be conducted in April, in ewes that have a BCS of >2.5 and that have passed their third month of lactation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Backward SDEs for optimal control of partially observed path-dependent stochastic systems : A control randomization approach

We introduce a suitable backward stochastic differential equation (BSDE) to represent the value of an optimal control problem with partial observation for a controlled stochastic equation driven by Brownian motion. Our model is general enough to include cases with latent factors in Mathematical finance. By a standard reformulation based on the reference probability method, it also includes the classical model where the observation process is affected by a Brownian motion (even in presence of a correlated noise), a case where a BSDE representation of the value was not available so far. This approach based on BSDEs allows for greater generality beyond the Markovian case, in particular our model may include path-dependence in the coefficients (both with respect to the state and the control), and does not require any nondegeneracy condition on the controlled equation. We use a randomization method, previously adopted only for cases of full observation, and consisting in a first step, in replacing the control by an exogenous process independent of the driving noise and in formulating an auxiliary (\u201crandomized\u201d) control problem where optimization is performed over changes of equivalent probability measures affecting the characteristics of the exogenous process. Our first main result is to prove the equivalence between the original partially observed control problem and the randomized problem. In a second step, we prove that the latter can be associated by duality to a BSDE, which then characterizes the value of the original problem as well

Update on the pathogenesis and genetics of Paget's disease of bone

Studies over the past two decades have led to major advances in the pathogenesis of Paget's disease of bone (PDB) and particularly on the role of genetic factors. Germline mutations of different genes have been identified, as a possible cause of this disorder, and most of the underlying pathways are implicated in the regulation of osteoclast differentiation and function, whereas other are involved in cell autophagy mechanisms. In particular, about 30 different germline mutations of the Sequestosome 1 gene (SQSTM1) have been described in a significant proportion of familial and sporadic PDB cases. The majority of SQSTM1 mutations affect the ubiquitin-binding domain of the protein and are associated to a more severe clinical expression of the disease. Also, germline mutations in the ZNF687 and PFN1 genes have been associated to severe, early onset, polyostotic PDB with increased susceptibly to neoplastic degeneration, particularly giant cell tumor. Mutations in the VCP (Valosin Containing Protein) gene cause the autosomal dominant syndrome "Inclusion Body Myopathy, PDB, Fronto-temporal Dementia," characterized by pagetic manifestations, associated with myopathy, amyotrophic lateral sclerosis and fronto-temporal dementia. Moreover, germline mutations in the TNFRSF11A gene, which encodes for RANK, were associated with rare syndromes showing some histopathological, radiological, and clinical overlap with PDB and in two cases of early onset PDB-like disease. Likewise, genome wide association studies performed in unrelated PDB cases identified other potential predisposition genes and/or susceptibility loci. Thus, it is likely that polygenic factors are involved in the PDB pathogenesis in many individuals and that modifying genes may contribute in refining the clinical phenotype. Moreover, the contribution of somatic mutations of SQSTM1 gene and/or epigenetic mechanisms in the pathogenesis of skeletal pagetic abnormalities and eventually neoplastic degeneration, cannot be excluded. Indeed, clinical and experimental observations indicate that genetic susceptibility might not be a sufficient condition for the clinical development of PDB without the concomitant intervention of viral infection, in primis paramixoviruses, and/or other environmental factors (e.g., pesticides, heavy metals or tobacco exposure), at least in a subset of cases. This review summarizes the most important advances that have been made in the field of cellular and molecular biology PDB over the past decades. © 2022 Gennari, Rendina, Merlotti, Cavati, Mingiano, Cosso, Materozzi, Pirrotta, Abate, Calabrese and Falchetti

Frontier in three-dimensional cave reconstruction—3D meshing versus textured rendering

Underground caves and their specific structures are important for geomorphological studies. This paper investigates the capabilities of a new modelling approach advanced for true-to-life three-dimensional (3D) reconstruction of cave with full resolution scan relative to 3D meshing. The cave was surveyed using terrestrial laser scanner (TLS) to acquire high resolution scans. The data was processed to generate a 3D-mesh model and textured 3D model using sub-sampled points and full resolution scan respectively. Based on both point and solid surface representation, comparative analysis of the strengths and weaknesses of the two approaches were examined in terms of data processing efficiency, visualization, interactivity and geomorphological feature representation and identification. The result shows that full scan point representation offers advantage for dynamic visualization over the decimated xyz point data because of high density of points and availability of other surface information like point normal, intensity and height which can be visualized in colour scale. For the reconstructed surface, mesh model is better with respect to interactivity and morphometric but 3D rendering shows superiority in visual reality and identification of micro detail of features with high precision. Complementary use of the two will provide better understanding of the cave, its development and processes

Combined antiretroviral therapy reduces hyperimmunoglobulinemia in HIV-1 infected children

Objective: To evaluate the effect of combined antiretroviral therapy on serum immunoglobulin (Ig) levels in HIV-1 perinatally infected children. Methods: Data from 1250 children recorded by the Italian Register for HIV Infection in Children from 1985 to 2002 were analysed. Since Ig levels physiologically vary with age, differences at different age periods were evaluated as differences in z-scores calculated using means and standard deviations of normal population for each age period. Combined antiretroviral therapy has become widespread in Italy since 1996, thus differences in Ig z-scores between the periods 1985-1995 and 1996-2002 were analysed. Data according to type of therapeutic regimen were also analysed. Results: Between the two periods 1985-1995 and 1996-2002, significant (P < 0.0001) decreases in IgG (6.29 ± 4.72 versus 4.44 ± 4.33), IgM (9.25 ± 13.32 versus 5.61 ± 7.93), and IgA (10.25 ± 15.68 versus 6.48 ± 11.56) z-scores, together with a parallel significant (P < 0.0001) increase in CD4 T-lymphocyte percentages, were found. These decreases were confirmed regardless of whether the children were receiving intravenous Ig or not. Ig z-scores were significantly higher in children receiving mono-therapy than in those receiving double-combined therapy (IgC, P < 0.0001; IgM, P = 0.003; IgA, P = 0.031) and in the latter children than in those receiving three or more drugs (P < 0.0001 for all z-scores). Ig z-scores correlated inversely with CD4 T-lymphocyte percentages and, directly, with viral loads. Conclusions: Our data show that in HIV-1 infected children combined antiretroviral therapy leads to reduction of hyperimmunoglobulinemia which parallels restoration of CD4 T-lymphocyte percentage and viral load decrease, which it turn probably reflects improved B-lymphocyte functions. © 2004 Lippincott Williams & Wilkins