Self-adaptive high-frequency injection based sensorless control for interior permanent magnet synchronous motor drives \u2020

Abstract: An auto-tuning and self-adaptation procedure for High Frequency Injection (HFI) based position and speed estimation algorithms in Interior Permanent Magnet Synchronous Motor (IPMSM) drives is proposed in this paper. Analytical developments show that, using conventional approaches, the dynamics of the high-frequency tracking loop varies with differential inductances, which in turn depend on the machine operating point. On-line estimation and adaptation of the small signal gain of the loop is proposed here, allowing accurate auto-tuning of the sensorless control scheme which does not rely on a priori knowledge of the machine parameters. On-line adaptation of Phase-Locked Loop (PLL) gains and of the injected voltage magnitude is also possible, leading to important advantages from the performance, loss and acoustic point of view. The theoretical basis of the method has been introduced first and the main concept demonstrated by means of simulations. Implementation has been carried out using the hardware of a commercial industrial drive and two Interior Permanent Magnet Synchronous Motors, namely a prototype and an off-the-shelf machine. Experimental tests demonstrate the feasibility and effectiveness of the proposal

High-Resolution monitoring of current rapid transformations on glacial and periglacial environments

Glacial and periglacial environments are highly sensitive to climatic changes. Processes of cryosphere degradation may strongly impact human activities and infrastructures, and need to be monitored for improved understanding and for mitigation/adaptation. Studying glacial and periglacial environments using traditional techniques may be difficult or not feasible, but new remote sensing techniques like terrestrial and aerial laser scanner opened new possibilities for cryospheric studies. This work presents an application of the terrestrial laser scanner (TLS) for monitoring the current rapid changes occurring on the Montasio Occidentale glacier (Eastern Italian alps), which is representative of low-altitude, avalanche-fed and debris-cover glaciers. These glaciers are quite common in the Alps but their reaction to climate changes is still poorly known. The mass balance, surface velocity fields, debris cover dynamics and effects of meteorological extremes were investigated by repeat high-resolution TLS scanning from September 2010 to October 2012. The results were encouraging and shed light on the peculiar response of this glacier to climatic changes, on its current dynamics and on the feedback played by the debris cover, which is critical for its preservation. The rapid transformations in act, combined with the unstable ice mass, large amount of loose debris and channeled runoff during intense rainfalls, constitute a potential area for the formation of large debris flows, as shown by field evidences and documented by the recent literature

Performances of a portable Fourier transform hyperspectral imaging camera for rapid investigation of paintings

Abstract: Scientific investigation in the cultural heritage field is generally aimed at the characterization of the constituent materials and the conservation status of artworks. Since the 1990s, reflectance spectral imaging proved able to map pigments, reveal hidden details and evaluate the presence of restorations in paintings. Over the past two decades, hyperspectral imaging has further improved our understanding of paints and of its changes in time. In this work, we present an innovative hyperspectral camera, based on the Fourier transform approach, utilising an ultra-stable interferometer and we describe its advantages and drawbacks with respect to the commonly used line- and spectral-scanning methods. To mitigate the weaknesses of the Fourier transform hyperspectral imaging, we propose a strategy based on the virtual extension of the dynamic range of the camera and on the design of an illumination system with a balanced emission throughout the spectral range of interest. The hyperspectral camera was employed for the analysis of a painting from the “Album of Nasir al-din Shah”. By applying analysis routines based on supervised spectral unmixing, we demonstrate the effectiveness of our camera for pigment mapping. This work shows how the proposed hyperspectral imaging camera based on the Fourier transform is a promising technique for robust and compact in situ investigation of artistic objects in conditions compatible with museum and archaeological sites. Graphic abstract: [Figure not available: see fulltext.

Delirium in HIV-infected patients admitted to acute medical wards post universal access to antiretrovirals in South Africa

Background. Delirium is associated with increased mortality and length of hospital stay. Limited data are available from HIV-infected acute hospital admissions in developing countries. We conducted a prospective study of delirium among acute medical admissions in South Africa (SA), a developing country with universal antiretroviral therapy (ART) access and high burdens of tuberculosis (TB) and non-communicable disease.Objectives. To identify the prevalence of, risk factors for and outcomes of delirium in HIV-infected individuals in acute general medical admissions.Methods. Three cohorts of adult acute medical admissions to Groote Schuur and Victoria Wynberg hospitals, Cape Town, SA, were evaluated for prevalent delirium within 24 hours of admission. Reference delirium testing was performed by either consultant physicians or neuropsychologists, using the Confusion Assessment Method.Results. The study included 1 182 acute medical admissions, with 318 (26.9%) HIV-infected. The median (interquartile range) age and CD4 count were 35 (30 - 43) years and 132 (61 - 256) cells/µL, respectively, with 140/318 (44.0%) using ART on admission. The prevalence of delirium was 17.6% (95% confidence interval (CI) 13.7 - 22.1) among HIV-infected patients, and delirium was associated with increased inpatient mortality. In multivariable logistic regression analysis, factors associated with delirium were age ≥55 years (adjusted odds ratio (aOR) 6.95 (95% CI 2.03 - 23.67); p=0.002), and urea ≥15 mmol/L (aOR 4.83 (95% CI 1.7 - 13.44); p=0.003), while ART use reduced risk (p=0.014). A low CD4 count, an unsuppressed viral load and active TB were not predictors of delirium; nor were other previously reported risk factors such as non-opportunistic acute infections or polypharmacy.Conclusions. Delirium is common and is associated with increased mortality in HIV-infected acute medical admissions in endemic settings, despite increased ART use. Older HIV-infected patients with renal dysfunction are at increased risk for inpatient delirium, while those using ART on admission have a reduced risk

Prolonged treatment of COVID-19 pneumonia with high-flow nasal oxygen: A story of oxygen and resilience

The COVID-19 pandemic has placed significant strain on the oxygen delivery infrastructure of health facilities in resource-constrained health systems. In this case report, we describe a patient with severe COVID-19 pneumonia who was managed with high-flow nasal oxygen for 40 days, with an eventual successful outcome. We discuss the oxygen delivery infrastructure needed to offer this intervention, as well as the psychosocial impact on those undergoing treatment

Five-year follow-up of participants diagnosed with chronic airflow obstruction in a South African Burden of Obstructive Lung Disease (BOLD) survey

Background. A community-based prevalence survey performed in two suburbs in Cape Town, South Africa (SA), in 2005, using the international Burden of Obstructive Lung Disease (BOLD) method, confirmed a prevalence of chronic airflow obstruction (CAO) in 23.1% of adults aged >40 years.Objectives. To study the clinical course and prognosis over 5 years of patients with CAO identified in the 2005 survey.Methods. Patients with CAO in 2005 were invited to participate. Standard BOLD and modified questionnaires were completed. Spirometry was performed using spirometers of the same make as in 2005.Results. Of 196 eligible participants from BOLD 2005, 45 (23.0%) had died, 8 from respiratory causes, 10 from cardiovascular causes and 6 from other known causes, while in 21 cases the cause of death was not known. On multivariate analysis, only age and Global initiative for Obstructive Lung Disease (GOLD) stage 4 disease at baseline were significantly associated with death. Of the 151 survivors, 11 (5.6% of the original cohort) were unavailable and 33 (16.8%) declined or had medical exclusions. One hundred and seven survivors were enrolled in the follow-up study (54.6%, median age 63.1 years, 45.8% males). Post-bronchodilator spirometry performed in 106 participants failed to confirm CAO, defined as a forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio of <0.7, in 16 participants (15.1%), but CAO was present in 90. The median decline in FEV1 was 28.9 mL/year (interquartile range –54.8 - 0.0) and was similar between GOLD stages. The median total decline in FVC was 75 mL, and was significantly greater in GOLD stage 1 (–350 mL) than in stages 2 or 3 (–80 mL and +140 mL, respectively; p<0.01). Fifty-eight participants with CAO in 2005 (64.4%) remained in the same GOLD stage, while 21 (23.3%) deteriorated and 11 (12.2%) improved by ≥1 stage. Only one-third were receiving any treatment for chronic obstructive pulmonary disease (COPD).Conclusions. The prevalence, morbidity and mortality of CAO and COPD in SA are high and the level of appropriate treatment is very low, pointing to underdiagnosis and inadequate provision of and access to effective treatments and preventive strategies for this priority chronic non-communicable disease

Asthma in the intensive care unit: A review of patient characteristics and outcomes

Background. Most asthma-related deaths occur in low- and middle-income countries, and South Africa (SA) is ranked fifth in global asthma mortality. Little is known about the characteristics and outcome of asthma patients requiring intensive care unit (ICU) admission in SA. Objectives. To identify and characterise patients with acute severe asthma admitted to the respiratory ICU at Groote Schuur Hospital, Cape Town, SA, in order to evaluate outcomes and identify predictors of poor outcomes in those admitted. Methods. We performed a retrospective descriptive study of patients with severe asthma admitted to the respiratory ICU at Groote Schuur Hospital between 1 January 2014 and 31 December 2019. Results. One hundred and three patients (110 admission episodes) were identified with an acute asthma exacerbation requiring ICU admission; all were mechanically ventilated. There was a female preponderance (53.6%; n=59/110), with a median (range) age overall of 33 (13 - 84) years. Of all admissions, 40 (36.4%) were current tobacco smokers and 16 (14.5%) patients with a history of substance abuse. Two thirds (60.0%; n=66/110) of the patients were using an inhaled corticosteroid (ICS). No predictors of mortality were evident in multivariate modelling, although those who died were older, and had higher Acute Physiology and Chronic Health Evaluation (APACHE II) scores and longer duration of admission. Only 59 of the surviving 96 individual patients (61.5%) attended a specialist pulmonology clinic after discharge. Conclusion. Among patients admitted to the respiratory ICU at Groote Schuur Hospital for asthma exacerbations, there was a high prevalence of smokers and poor coverage with inhaled ICSs. Although mortality was low compared with general ICU mortality, more needs to be done to prevent acute severe asthma exacerbations

Public views of the Sustainable Development Goals across countries

The United Nation’s 17 Sustainable Development Goals (SDGs) offer an extensive framework for coordinating and shaping government policies, and for engaging the public with sustainability. Public understanding of the SDGs and sustainability can influence this engagement, as people are more likely to accept and share information consistent with their own understanding. We identify public understandings of SDGs through mental maps of how people relate the SDGs to environmental, social and economic sustainability. Using responses from 12 developed/developing countries (n = 2,134), we identified four mental maps that varied mainly on two dimensions, which diverged from some expert models. Some people’s mental maps identified tension between achieving environmental versus social sustainability, whereas for others the tension was between economic sustainability and the other two sustainability elements. Some people related different SDGs to each element of sustainability, whereas others saw all SDGs as targeting the same sustainability element(s). These findings highlight opportunities and challenges to engage the public with sustainability more effectively, especially with wide-ranging initiatives such as a Green New Deal. We observed cultural differences but we also identified a dominant mental map across countries that could serve as a default model for communicating sustainability internationally

Five-year follow-up of participants diagnosed with chronic airflow obstruction in a South African Burden of Obstructive Lung Disease (BOLD) survey

Background. A community-based prevalence survey performed in two suburbs in Cape Town, South Africa (SA), in 2005, using the international Burden of Obstructive Lung Disease (BOLD) method, confirmed a prevalence of chronic airflow obstruction (CAO) in 23.1% of adults aged >40 years. Objectives. To study the clinical course and prognosis over 5 years of patients with CAO identified in the 2005 survey. Methods. Patients with CAO in 2005 were invited to participate. Standard BOLD and modified questionnaires were completed. Spirometry was performed using spirometers of the same make as in 2005. Results. Of 196 eligible participants from BOLD 2005, 45 (23.0%) had died, 8 from respiratory causes, 10 from cardiovascular causes and 6 from other known causes, while in 21 cases the cause of death was not known. On multivariate analysis, only age and Global initiative for Obstructive Lung Disease (GOLD) stage 4 disease at baseline were significantly associated with death. Of the 151 survivors, 11 (5.6% of the original cohort) were unavailable and 33 (16.8%) declined or had medical exclusions. One hundred and seven survivors were enrolled in the follow-up study (54.6%, median age 63.1 years, 45.8% males). Post-bronchodilator spirometry performed in 106 participants failed to confirm CAO, defined as a forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio of <0.7, in 16 participants (15.1%), but CAO was present in 90. The median decline in FEV1 was 28.9 mL/year (interquartile range –54.8 - 0.0) and was similar between GOLD stages. The median total decline in FVC was 75 mL, and was significantly greater in GOLD stage 1 (–350 mL) than in stages 2 or 3 (–80 mL and +140 mL, respectively; p<0.01). Fifty-eight participants with CAO in 2005 (64.4%) remained in the same GOLD stage, while 21 (23.3%) deteriorated and 11 (12.2%) improved by ≥1 stage. Only one-third were receiving any treatment for chronic obstructive pulmonary disease (COPD). Conclusions. The prevalence, morbidity and mortality of CAO and COPD in SA are high and the level of appropriate treatment is very low, pointing to underdiagnosis and inadequate provision of and access to effective treatments and preventive strategies for this priority chronic non-communicable disease.info:eu-repo/semantics/publishedVersio

Morphological and Chemical Investigation of Ovarian Structures in a Bovine Model by Contrast-Enhanced X-ray Imaging and Microscopy

An improved understanding of an ovary’s structures is highly desirable to support advances in folliculogenesis knowledge and reproductive medicine, with particular attention to fertility preservation options for prepubertal girls with malignant tumors. Although currently the golden standard for structural analysis is provided by combining histological sections, staining, and visible 2D microscopic inspection, synchrotron radiation phase-contrast microtomography is becoming a new challenge for three-dimensional studies at micrometric resolution. To this aim, the proper use of contrast agents can improve the visualization of internal structures in ovary tissues, which normally present a low radiopacity. In this study, we report a comparison of four staining protocols, based on iodine or tungsten containing agents, applied to bovine ovarian tissues fixed in Bouin’s solution. The microtomography (microCT) analyses at two synchrotron facilities under different set-ups were performed at different energies in order to maximize the image contrast. While tungsten-based agents allow large structures to be well identified, Iodine ones better highlight smaller features, especially when acquired above the K-edge energy of the specific metal. Further scans performed at lower energy where the setup was optimized for overall quality and sensitivity from phase-contrast still provided highly resolved visualization of follicular and intrafollicular structures at different maturation stages, independent of the staining protocol. The analyses were complemented by X-ray Fluorescence mapping on 2D sections, showing that the tungsten-based agent has a higher penetration in this type of tissues