33 research outputs found
Adaptive Backstepping Integral Sliding Mode Control for 5DOF Barge-Type OFWT under Output Constraint
This article presents a new control solution for a dynamical model of a translational oscillator with a rotational actuator (TORA) based on multi-body dynamics for a barge-type offshore floating wind turbine (OFWT). TORA has been employed as an active structural control strategy. The solution of bounding the output movements of platform pitch and tower bending angle to a certain limit, along with mitigating the OFWT vibrations due to environmental disturbances and uncertainties, is presented in this novel control framework. This new control algorithm consists of a high-gain observer (HGO)-based adaptive backstepping integral sliding mode control (ISMC) and a barrier Lyapunov function (BLF). This guarantees satisfying the constraints on the states and effectively resolves the problem of the unavailability of the system states. The proposed control law based on the BLF has been compared with an adaptive backstepping ISMC to show the efficiency of the output-constraint control scheme. Through MATLAB/SIMULINK numerical simulations and their numeric error table, the effectiveness of the proposed control scheme has been examined. The results confirm the validity and efficiency of the proposed control approaches
GERM CELL TUMOURS OF THE OVARY IN CHILDREN AND ADOLESCENTS: A CLINICAL STUDY OF 109 PATIENTS IN A SPECIALIZED CANCER CENTRE
Objective: Paediatric ovarian germ cell tumours (GCTs) are rare tumours withmalignant tumours extremely rare.Methods: All the paediatric patients who received treatment for histology proven ovarian GCT at Shaukat Khanum Memorial Cancer Hospital from January 2006 to December 2014 were retrospectively reviewed. Patients over the age of 18 years were excluded from the study. A total of 109 patients were included in the study. A set of parameters were identified to record initial clinical presentation and examination, imaging and laboratory investigations including tumour marker levels. Decisions of multidisciplinary team meetings, surgical treatment, neo adjuvant, adjuvant chemotherapy and radiation data retrieved. Data analysiscarried out using SPSS 20.Results: In total 109 girls presented to our hospital during the study period, most of them above the age of 5 years, with dysgerminoma being the most common followed by yolk sac tumour. Most of the patients received treatment outside our hospital and were referred here for chemoradiotherapy. Fertility preserving surgery was the most commonly performed surgical procedure with a mean follow-up of 50.4 months and >75% overall 5-year survival.Conclusion: Regardless of histologic types, the outcomes of GCT can be improved with a multidisciplinary approach.Key words: Dysgerminomas, germ cell tumours, ovarian tumour
An Ongoing Futuristic Career of Metal–Organic Frameworks and Ionic Liquids, A Magical Gateway to Capture CO<sub>2</sub>; A Critical Review
Carbon capture and storage (CCS) technologies are the “knight in shining armor” that can save humanity from burnout in the longer term, minimizing damage from CO2 emissions by keeping them out of the atmosphere. Metal–organic frameworks (MOFs) have received a promising career for CO2 capture due to their high porosity, surface area, excellent metal-to-ligand interaction, and good affinity to capture CO2 molecules. On the other hand, Ionic liquids (ILs) as emerging solvents have reported a significant influence on CO2 solubility due to their wide range of tunability in the selection of a variety of cations and anions along with the advantage of nonvolatility, high thermal stability, and nonflammability. The current Review highlights the recent progress and ongoing careers of employing MOFs and ILs in carbon capture technologies before their commercialization on a large scale. A brief overview of CO2 capturing using MOFs and ILs is given under the influence of their possible functionalization to enhance their CO2 separation. Information on the possible integration of MOFs-ILs as a composite system or membrane-based gas separation is also presented in detail. The integration has a high potential to capture CO2 while minimizing the unit operation costs for a stable, efficient, and smooth industrial gas separation operation. Present work attempts to link the chemistry of MOF and IL and their successful hybridization (MOF-IL composite) to process the economics for CO2 capture
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
OPTIMISATION STUDIES ON RUBBER SEED OIL BASED METHYL ESTER SYNTHESIS VIA HYDRODYNAMIC CAVITATION TECHNOLOGY
Hydrodynamic cavitation (HC) technology is a viable way to produce sustainable biodiesel from high free fatty acid non-edible feedstock. This technology has affirmative environmental impacts with lower energy consumption and shorter reaction time, which offers a cleaner possibility. The limitation of conventional mechanical stirring (MS) process involved longer reaction time to obtain methyl ester content. Four newly designed orifice plates were studied as a cavitating device in HC reactor. HC reactor was connected to the diaphragm pump in a close loop reactor. The compressed air was supplied to operate the double diaphragm pump, which is the main device to dissipate the energy in a HC reacto
OPTIMIZATION STUDIES ON POST BLENDING OF CRUDE PALM AND RUBBER SEED OIL FATTY ACID METHYL ESTERS
In avoiding the major issues of fossil fuel depletion and the environmental concerns,
biodiesel is one of the most feasible sources of alternative energy. Rubber seeds, due
to its non-edible characteristics have a potential to be converted to biodiesel. Its
utilization will help to resolve food versus fuel controversy. Malaysia has a vast
number of palm and rubber plantations that can supply sufficient seeds for biodiesel
production. In present work, parametric studies and optimized conditions were
determined via response surface methodology (RSM), using the central composite
design (CCD) of the Design Expert 8.0 software. The parameters studied for solvent
extraction of rubber seeds were solvent to seed ratio, temperature, extraction time and
drying time of the seeds. A parametric study was also conducted to determine the
effect of alcohol to oil (A:0) ratio, catalyst loading, reaction time and temperature on
acid esterification and base transesterification process
Diagnostic Accuracy of Serology Testing for Helicobacter Pylori in Perforated Peptic Ulcer
Background: To compare H. pylori serology testing with histopathological biopsy, in patients with perforated peptic ulcer.Methods: This cross sectional study was performed to document the diagnostic accuracy of H. pylori serology in patients with perforated duodenal ulcer. Perforated peptic ulcer was diagnosed on the basis of history, clinical findings and presence of free gas under the diaphragm on an x-ray. All individuals fulfilling inclusion criteria underwent laparotomy. Blood samples were sent for H Pylori serology by enzyme linked immunosorbent assay. At the same time, gastric antral biopsies were taken for histopathology for H. pylori.Results: Sstudy included 191 patients with diagnosed perforated peptic ulcer at laparotomy. Majority (70.2%) were males. The mean age was 41.72 years. In majority the perforation was seen along the first part of duodenum (76.4%). H. pylori serology was positive in 69.1% patients. One hundred and thirty nine (72.8%) patients had positive histopathology for H pylori. Out of these, 92.8% also had a positive H. pylori serology. Fifty two (27.2%) patients had negative histopathology for H. pylori. Out of these 5.8% had a positive serology test. One hundred and twenty nine were true positive i-e both had positive histopathology and serology and 52 were true negative i.e., they had both a negative serology and a negative histopathology. The results were therefore correct in 94.76%. The overall accuracy of serology in comparison to histopathology was 94.76%. The calculated sensitivity, specificity, positive predictive value and negative predictive value of serology in comparison to histopathology was 92.8%, 94.5%, 97.7% and 83.9% respectively.Conclusion: A high prevalence of H. pylori infection was found in patients with perforated peptic ulcers. Overall accuracy of serology in comparison to histopathology was 94.76%. Serological testing is a useful noninvasive method for the diagnosis of Helicobacter pylori infection