Reliability and Safety Modeling of a Digital Feed-Water Control System

 إن الكثير من الأجهزة الرقمية وأنظمة التحكم المضمنة في معدات الرعاية الصحية الطبية الحيوية، وأجهزة الطيران، والصناعات النووية لها نتائج واضحة لأنماط الفشل المختلفة. يمكن أن تؤثر حالات الفشل هذه على سلوك النظام الرقمي الشامل للسلامة وقدرته على تقديم سمات الموثوقية الخاصة به إذا لم يتم الكشف عن أي منطقة معيبة يمكن أن تكون مكونًا من مكونات الأجهزة أو رمز البرنامج المضمّن داخل النظام الرقمي وإصلاحه بشكل مناسب. يمكن تحقيق تحليل السلامة والموثوقية للأنظمة الهامة للسلامة باستخدام تقنيات نمذجة ماركوف التي يمكن أن تعبر عن السلوك الديناميكي والتجديدي لنظام التحكم الرقمي. تمثل حالات معينة في النظام فشل النظام، بينما تمثل حالات أخرى سلوكًا خاليًا من الأخطاء أو عملية صحيحة في وجود أخطاء. تقدم هذه الورقة تطوير نمذجة السلامة والموثوقية لنظام التحكم الرقمي في مياه التغذية باستخدام نماذج السلسلة القائمة على ماركوف. تم افتراض جميع حالات ماركوف والتحولات بين هذه الحالات وحسابها من منطق التحكم لنظام التحكم الرقمي. أخيرًا ، استنادًا إلى نتائج المحاكاة لنمذجة نظام التحكم الرقمي في مياه التغذية ، فإن النظام يلبي متطلبات الموثوقية الخاصة به مع احتمال أن يكون في حالة التشغيل الكامل هو 0.99 على مدار 6 أشهر.Much digital instrumentation and control systems embedded in the critical medical healthcare equipment, aerospace devices, and nuclear industry have obvious consequence of different failure modes. These failures can affect the behavior of the overall safety-critical digital system and its ability to deliver its dependability attributes if any defected area that could be a hardware component or software code embedded inside the digital system is not detected and repaired appropriately. The safety and reliability analysis of safety-critical systems can be accomplished with Markov modeling techniques which could express the dynamic and regenerative behavior of the digital control system. Certain states in the system represent system failure, while others represent fault free behavior or correct operation in the presence of faults. This paper presents the development of a safety and reliability modeling of a digital feedwater control system using Markov-based chain models. All the Markov states and the transitions between these states were assumed and calculated from the control logic for the digital control system. Finally, based on the simulation results of modeling the digital feedwater control system, the system does meet its reliability requirement with the probability of being in fully operational states is 0.99 over a 6 months’ time. &nbsp

In-Shoe Plantar Pressure System To Investigate Ground Reaction Force Using Android Platform

Human footwear is not yet designed to optimally relieve pressure on the heel of the foot. Proper foot pressure assessment requires personal training and measurements by specialized machinery. This research aims to investigate and hypothesize about Preferred Transition Speed (PTS) and to classify the gait phase of explicit variances in walking patterns between different subjects. An in-shoe wearable pressure system using Android application was developed to investigate walking patterns and collect data on Activities of Daily Living (ADL). In-shoe circuitry used Flexi-Force A201 sensors placed at three major areas: heel contact, 1st metatarsal, and 5th metatarsal with a PIC16F688 microcontroller and Bluetooth module. This method provides a low-cost instantaneous solution to both wear and records plantar foot simultaneously. Data acquisition used internal local memory to store pressure logs for offline data analysis. Data processing used the perpendicular slope to determine peak pressure and time of index. Statistical analysis can utilize to discover foot deformity. The empirical results in one subject showed weak linearity between normal and fast walk and a significant difference in body weight acceptance between normal and slow walk. In addition, T-test hypothesis testing between two healthy subjects, with , illustrated a significant difference in their Initial Contact pressure and no difference between their peak-to-peak time interval. Preferred Transition Speed versus VGRF was measured in 19 subjects. The experiments demonstrated that vertical GRF averagely increased 18.46% when the speed changed from 50% to 75% of PTS with STD 4.78. While VGRF increased 21.24% when the speed changed from 75% to 100% of PTS with STD 7.81. Finally, logistic regression between 12 healthy subjects demonstrated a good classification with 82.6% accuracy between partial foot bearing and their normal walk

Reliability and Safety Modeling of a Digital Feed Water Control System

Much digital instrumentation and control systems embedded in the critical medical healthcare equipment aerospace devices and nuclear industry have obvious consequence of different failure modes. These failures can affect the behavior of the overall safety critical digital system and its ability to deliver its dependability attributes if any defected area that could be a hardware component or software code embedded inside the digital system is not detected and repaired appropriately. The safety and reliability analysis of safety critical systems can be accomplished with Markov modeling techniques which could express the dynamic and regenerative behavior of the digital control system. Certain states in the system represent system failure while others represent fault free behavior or correct operation in the presence of faults. This paper presents the development of a safety and reliability modeling of a digital feedwater control system using Markov based chain models. All the Markov states and the transitions between these states were assumed and calculated from the control logic for the digital control system. Finally based on the simulation results of modeling the digital feedwater control system the system does meet its reliability requirement with the probability of being in fully operational states is 0.99 over a 6 months time.Comment: 13 pages, 7 figures, conferenc

Right mini-thoracotomy versus median sternotomy for mitral valve replacement

Background: The advantages of minimally invasive mitral valve surgery over the conventional approach is still debated. This study aimed to evaluate early outcomes after mitral valve replacement (MVR) using the right mini-thoracotomy (RMT) versus median sternotomy (MS). Methods: We prospectively included 60 patients who had MVR from May 2015 to June 2017. We classified patients into two groups; Group A (n= 30) had RMT, and Group B (n= 30) had MS. Postoperative pain score, wound satisfaction, and clinical and echocardiographic outcomes were compared between both groups. Results: The mean age was 39.90 ± 12.34 years in Group A and 45.75 ± 13.10 years in Group B (p= 0.08). Preoperative and echocardiographic data showed no statistical significance difference between the groups. Group A had longer aortic cross-clamp (118.85 ± 40.56 vs. 70.75 ± 24.81 minutes, p<0.001) and cardiopulmonary bypass times (186.70 ± 67.44 vs. 104.65 ± 42.60 minutes, p<0.001).  Group B had more blood loss (565 ± 344.3 vs. 241.5 ±89.16 ml/24 hours, p<0.001). The median pain score was 1 (range: 1- 3) in Group A and 4 (2- 8) in Group B (p<0.001), and the median wound satisfaction was 1.5 (1- 4) in Group A and 4 (1- 7) in Group B (p<0.001).  Wound infection occurred in 1 (3.3%) patient in Group A and 6 (20%) patients in Group B (p=0.04). Conclusion: Mitral valve replacement through the right mini-thoracotomy could be a safe alternative to median sternotomy. The right mini-thoracotomy was associated with longer operative times but better pain and wound satisfaction scores and lower wound infection

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Oxidative stability of edible oils via addition of pomegranate and orange peel extracts

The main objective of the present study was to improve the oxidative stability of sunflower oil (SFO) and soybean oil (SBO). The aqueous ethanol extracts (80% ethanol) of pomegranate and Baladi orange peels were used as natural antioxidants at concentrations of 800 and 1,200 ppm in SFO and SBO in comparison to butylated hydroxytoluene (BHT). Their antioxidant activities were estimated via the Rancimat method and over 24 days of storage at 65°C. The effect of extracts on the stability of sunflower and soybean oils during the storage period was studied by measuring the peroxide value (PV), conjugated dienes (CD) at 232 nm, conjugated trienes (CT) at 270 nm, free fatty acids (FFAs), iodine value (IV), and the refractive index (RI). A great difference in PVs was observed between the control sample and the oil samples containing natural extracts which slowed the rate of peroxide formation. Generally, the results showed that during the storage period at 65°C, the conjugated diene formation followed a similar pattern relative to PV accumulation. The PV, CD, CT, FFA, and RI values of SFO and SBO containing a pomegranate peel extract (PPE) and Baladi orange peel extract (BOPE) at concentrations of 800 and 1,200 ppm were lower than those of SFO and SBO containing 200 ppm BHT, and this trend became apparent during the storage period. The rate of reduction of IV in the control was higher than that in SFO and SBO containing both synthetic and natural antioxidants. These findings confirmed that the natural antioxidants under investigation could be used as alternatives to synthetic antioxidants to improve the oxidative stability of edible oils in the food industry