197 research outputs found

    Data-driven modeling of the flow field between two PWR surrogate bundles under seismic conditions using bagging-optimised dynamic mode decomposition (BOP-DMD)

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    LAUREA MAGISTRALEl funzionamento in sicurezza dei reattori nucleari sia in condizioni nominali che acciden-tali è un requisito obbligatorio per la progettazione di qualsiasi impianto nucleare. In particulare, una delle condizioni accidentali più critiche è rappresentata dai terremoti: tuttavia, i lavori di letteratura che discutono la risposta degli elementi di combustibile nel nocciolo del reattore e come interagiscono con il fluido moderatore in condizioni sismiche sono limitati. Le tecniche di misurazione diretta dei parametri del campo di flusso sono molto complicate ed estremamente costose: per studiare questi fenomeni, lo stato dell’arte è usare modelli di interazione fluido-struttura. Tuttavia, questi modelli presentano alcune limitazioni, come gli elevati costi computazionali e l’incertezza sistematica. Per questo motivo, la modellazione guidata dai dati (data-driven modelling come tecnica di analisi può essere utilizzata per ridurre i costi computazionali e ottenere risultati sufficientemente accurati per il campo nucleare. In questo lavoro, utilizziamo la Bagging-Optimized Dynamic Mode Decomposition (BOP-DMD) per fornire previsioni accurate dei parametri del campo di flusso del refrigerante intorno a elementi di combustibile surrogati (rappresenta-tivi di quelli di un PWR) in condizioni sismiche, quantificando inoltre l’incertezza spaziale e temporale. Questa tecnica di riduzione d’ordine (MOR) non richiede l’implementazione delle equazioni fisiche del modello, ma richiede solo la presenza di un insieme di dati di qualsiasi provenienza: in particolare, nel nostro lavoro usiamo dati sperimentali proveni-enti dall’impianto ICARE, ovvero misure sperimentali dei campi di velocità 2D del flusso, ottenute usando la tecnica della Particle Image Velocimetry (PIV). Abbiamo sviluppato l’algoritmo BOP-DMD in MATLAB, confermando la validità del metodo BOP-DMD per la ricostruzione di campi di flusso complessi e per la predizione del comportamento futuro del sistema con livelli di accuratezza elevati e bassi tempi di calcolo.The safe operation of nuclear reactors under accidental operating conditions is a mandatory requirement for any plant design. One of the most challenging conditions is represented by earthquakes: however, works of literature discussing the response of reactor core bundles and their interaction with the moderator under seismic conditions are limited. Direct measuring techniques of flow field parameters are highly complicated and extremely expensive, hence fluid-structure interaction models are proposed to solve such problems. However, these models still have some limitations, for example, high computational costs and systematic uncertainty. As such, data-driven modeling as a data analysis technique can be used to reduce computational costs whilst obtaining results of high enough accuracy. In this work, we use Bagging-Optimized Dynamic Mode Decomposition (BOP-DMD) to provide stable forecasting of flow field parameters of coolant flow around PWR surrogate bundles under seismic conditions with spatial and temporal uncertainty quantification. This equation-free Model Order Reduction technique (MOR), which we have built using MATLAB through the use of experimental data, is suitable for future data prediction with large accuracy limits and low computational time. The benchmark of this work is the ICARE experimental facility, which is an experimental facility that studies the coolant flow between two PWR surrogate bundles under seismic conditions. Data used in this work for the training and validation of the model are obtained from 2D experimental measurements of flow velocity fields around PWR surrogate bundles under seismic conditions using the Particle Image Velocimetry technique (PIV). The study confirms the Validity of the BOP-DMD method to provide field reconstruction of complex flow fields up to high certainty levels

    Exploring the Excluded Stomach: A Case Series of Novel Endoscopic Techniques to Diagnose Gastric Cancer in the Excluded Stomach After Roux-en-Y Gastric Bypass Surgery

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    Gastric cancer is the fifth most common malignancy worldwide and the fourth leading cause of cancer-related deaths. The diagnosis is usually made by direct visualization with supporting histopathology. However, patients with gastric bypass surgery pose a challenge in diagnosis due to the difficulty in the evaluation of the excluded stomach. We present two cases of gastric cancer in the excluded stomach after Roux-en-Y gastric bypass (RYGB) surgery was diagnosed using two different endoscopic approaches

    Synthesize of bio-based encapsulated nano urea modified hydroxyapatite for controlling release of nitrogen and enhancing green bean yield

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    The massive rise in the world population requires increasing food production, and the world needs to decrease agricultural inputs like agrochemicals to preserve natural resources. The low nutrient use efficiency of conventional fertilizers has always been a concern because of their impact on the environment, and they are considered a waste of natural resources, which is against sustainability goals. Their low efficiency is attributed to their high solubility and fast release into the soil. Controlled-release fertilizers (CRFs) can reduce nutrient loss, which increases their efficiency and controls environmental pollution. In this study, single- and double-layers coating of biopolymers were applied to encapsulate nano urea-modified hydroxyapatite to control nitrogen release in soil. Hydroxyapatite was synthesized using the wet chemical precipitation method and two different rodlike and mesoporous hydroxyapatites were obtained. Nano-hydroxyapatite that had been synthesized was mixed with urea in two different amounts: 4:1 and 8:1. Biopolymers were then added on top. The current CRF synthesis strategy focuses on using low-cost, widespread biorefinery materials to decrease the manufacturing cost of CRFs. The nitrogen release rate of the synthesized CRFs and commercial urea in water and soil was studied. In field experiments, the impact of CRFs on green bean growth and yield was studied. The results showed that both single and double-coated CRFs reduced the N release rate in the soil and increased the fertilizer's longevity to 24 days, compared to 6 days for conventional urea. The total yield of green beans increased by 48%-120% by applying 75% of the recommended dose compared with that obtained with the full dose of conventional urea (control). Also, applying double-coated CRFs at N level of 25% of the recommended dose gives a green bean yield equal to the control. The recommended treatment is SC-CRF prepared with C-HA applied at N rate of 75% to match the future increase in the required amount of food

    Combined Use of Modal Analysis and Machine Learning for Materials Classification

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    The present study deals with modal work that is a type of framework for structural dynamic testing of linear structures. Modal analysis is a powerful tool that works on the modal parameters to ensure the safety of materials and eliminate the failure possibilities. The concept of classification through this study is validated for isotropic and orthotropic materials, reaching up to a 100% accuracy when deploying the machine learning approach between the mode number and the associated frequency of the interrelated variables that were extracted from modal analysis performed by ANSYS. This study shows a new classification method dependent only on the knowledge of resonance frequency of a specific material and opens new directions for future developments to create a single device that can identify and classify different engineering materials

    Hydro Laundry Enterprise / Amar Mukhtar Abdul Rahman ...[et al.]

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    Hydro Laundry Enterprise, is a company which focuses on laundry service. We are aware that university students and residents around Bandar Seri Alam need laundry service. So we promote our service a we think that it might has potential to be a good business. Nowadays almost everything in our world now are working fast and efficiently, so we promote as self-service laundry because it can saves time. We also aware that people around Bandar Seri Alam majority are people who have carrier and busy in working, so they may not have much time to do their laundry and that is why we opens this business. University students all need this kind of service to reduce their burden in doing their laundry. Our mission is to expand our company by opening 2-3 more branches throughout the the area in 5 years. Besides, we also want to improve our quality and quantity of our facilities and be a well-known self-service laundry company. This can be achieved by the cooperation and efforts among the partners to promote company

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    Global, regional, and national burden of stroke and its risk factors, 1990–2021 : a systematic analysis for the Global Burden of Disease Study 2021

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    Background: Up-to-date estimates of stroke burden and attributable risks and their trends at global, regional, and national levels are essential for evidence-based health care, prevention, and resource allocation planning. We aimed to provide such estimates for the period 1990–2021. Methods: We estimated incidence, prevalence, death, and disability-adjusted life-year (DALY) counts and age-standardised rates per 100 000 people per year for overall stroke, ischaemic stroke, intracerebral haemorrhage, and subarachnoid haemorrhage, for 204 countries and territories from 1990 to 2021. We also calculated burden of stroke attributable to 23 risk factors and six risk clusters (air pollution, tobacco smoking, behavioural, dietary, environmental, and metabolic risks) at the global and regional levels (21 GBD regions and Socio-demographic Index [SDI] quintiles), using the standard GBD methodology. 95% uncertainty intervals (UIs) for each individual future estimate were derived from the 2·5th and 97·5th percentiles of distributions generated from propagating 500 draws through the multistage computational pipeline. Findings: In 2021, stroke was the third most common GBD level 3 cause of death (7·3 million [95% UI 6·6–7·8] deaths; 10·7% [9·8–11·3] of all deaths) after ischaemic heart disease and COVID-19, and the fourth most common cause of DALYs (160·5 million [147·8–171·6] DALYs; 5·6% [5·0–6·1] of all DALYs). In 2021, there were 93·8 million (89·0–99·3) prevalent and 11·9 million (10·7–13·2) incident strokes. We found disparities in stroke burden and risk factors by GBD region, country or territory, and SDI, as well as a stagnation in the reduction of incidence from 2015 onwards, and even some increases in the stroke incidence, death, prevalence, and DALY rates in southeast Asia, east Asia, and Oceania, countries with lower SDI, and people younger than 70 years. Globally, ischaemic stroke constituted 65·3% (62·4–67·7), intracerebral haemorrhage constituted 28·8% (28·3–28·8), and subarachnoid haemorrhage constituted 5·8% (5·7–6·0) of incident strokes. There were substantial increases in DALYs attributable to high BMI (88·2% [53·4–117·7]), high ambient temperature (72·4% [51·1 to 179·5]), high fasting plasma glucose (32·1% [26·7–38·1]), diet high in sugar-sweetened beverages (23·4% [12·7–35·7]), low physical activity (11·3% [1·8–34·9]), high systolic blood pressure (6·7% [2·5–11·6]), lead exposure (6·5% [4·5–11·2]), and diet low in omega-6 polyunsaturated fatty acids (5·3% [0·5–10·5]). Interpretation: Stroke burden has increased from 1990 to 2021, and the contribution of several risk factors has also increased. Effective, accessible, and affordable measures to improve stroke surveillance, prevention (with the emphasis on blood pressure, lifestyle, and environmental factors), acute care, and rehabilitation need to be urgently implemented across all countries to reduce stroke burden. Funding: Bill & Melinda Gates Foundation. © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. **Please note that there are multiple authors for this article therefore only the name of the first 30 including Federation University Australia affiliate “Sheikh Alif, Balasankar Ganesan, Muhammad Aziz Rahman" is provided in this record**

    Changing life expectancy in European countries 1990–2021: a subanalysis of causes and risk factors from the Global Burden of Disease Study 2021

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    Background Decades of steady improvements in life expectancy in Europe slowed down from around 2011, well before the COVID-19 pandemic, for reasons which remain disputed. We aimed to assess how changes in risk factors and cause-specific death rates in different European countries related to changes in life expectancy in those countries before and during the COVID-19 pandemic. Methods We used data and methods from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 to compare changes in life expectancy at birth, causes of death, and population exposure to risk factors in 16 European Economic Area countries (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, and Sweden) and the four UK nations (England, Northern Ireland, Scotland, and Wales) for three time periods: 1990–2011, 2011–19, and 2019–21. Changes in life expectancy and causes of death were estimated with an established life expectancy cause-specific decomposition method, and compared with summary exposure values of risk factors for the major causes of death influencing life expectancy. Findings All countries showed mean annual improvements in life expectancy in both 1990–2011 (overall mean 0·23 years [95% uncertainty interval [UI] 0·23 to 0·24]) and 2011–19 (overall mean 0·15 years [0·13 to 0·16]). The rate of improvement was lower in 2011–19 than in 1990–2011 in all countries except for Norway, where the mean annual increase in life expectancy rose from 0·21 years (95% UI 0·20 to 0·22) in 1990–2011 to 0·23 years (0·21 to 0·26) in 2011–19 (difference of 0·03 years). In other countries, the difference in mean annual improvement between these periods ranged from –0·01 years in Iceland (0·19 years [95% UI 0·16 to 0·21] vs 0·18 years [0·09 to 0·26]), to –0·18 years in England (0·25 years [0·24 to 0·25] vs 0·07 years [0·06 to 0·08]). In 2019–21, there was an overall decrease in mean annual life expectancy across all countries (overall mean –0·18 years [95% UI –0·22 to –0·13]), with all countries having an absolute fall in life expectancy except for Ireland, Iceland, Sweden, Norway, and Denmark, which showed marginal improvement in life expectancy, and Belgium, which showed no change in life expectancy. Across countries, the causes of death responsible for the largest improvements in life expectancy from 1990 to 2011 were cardiovascular diseases and neoplasms. Deaths from cardiovascular diseases were the primary driver of reductions in life expectancy improvements during 2011–19, and deaths from respiratory infections and other COVID-19 pandemic-related outcomes were responsible for the decreases in life expectancy during 2019–21. Deaths from cardiovascular diseases and neoplasms in 2019 were attributable to high systolic blood pressure, dietary risks, tobacco smoke, high LDL cholesterol, high BMI, occupational risks, high alcohol use, and other risks including low physical activity. Exposure to these major risk factors differed by country, with trends of increasing exposure to high BMI and decreasing exposure to tobacco smoke observed in all countries during 1990–2021. Interpretation The countries that best maintained improvements in life expectancy after 2011 (Norway, Iceland, Belgium, Denmark, and Sweden) did so through better maintenance of reductions in mortality from cardiovascular diseases and neoplasms, underpinned by decreased exposures to major risks, possibly mitigated by government policies. The continued improvements in life expectancy in five countries during 2019–21 indicate that these countries were better prepared to withstand the COVID-19 pandemic. By contrast, countries with the greatest slowdown in life expectancy improvements after 2011 went on to have some of the largest decreases in life expectancy in 2019–21. These findings suggest that government policies that improve population health also build resilience to future shocks. Such policies include reducing population exposure to major upstream risks for cardiovascular diseases and neoplasms, such as harmful diets and low physical activity, tackling the commercial determinants of poor health, and ensuring access to affordable health services.publishedVersio
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