27 research outputs found

    Design and implementation of proposed 320 bit RC6-cascaded encryption/decryption cores on altera FPGA

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    This paper attempts to build up a simple, strong and secure cryptographic algorithm. The result of such an attempt is “RC6-Cascade” which is 320-bits RC6 like block cipher. The key can be any length up to 256 bytes. It is a secret-key block cipher with precise characteristics of RC6 algorithm using another overall structure design. In RC6-Cascade, cascading of F-functions will be used instead of rounds. Moreover, the paper investigates a hardware design to efficiently implement the proposed RC6-Cascade block cipher core on field programmable gate array (FPGA). An efficient compact iterative architecture will be designed for the F-function of the above algorithm. The goal is to design a more secure algorithm and present a very fast encryption core for low cost and small size applications

    Performance assessment of parabolic trough collector (ptc) by using three passes receiver for preheating the fuel oil under Iraq climate for different mass flow rates

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    An alternative design receiver of parabolic trough collector (PTC) has been discussed in the present study. The three passes design (3p) receiver made from copper and coated with selective black paint was studied and optimized experimentally. Mass flow rates were varied alongside number of days. The proposed design was compared with the PTC equipped with smooth receiver (SM). The aforementioned variations resulted in the experiments performed in September 2018. The 17th, 18th, 19th, and 20th, were chosen for the PTC with smooth receiver, while 25th , 26th, 27th, and 28th were for the receiver with three passes). The solar irradiances for these days were similar. The heat transfer fluid (HTF) was fuel oil. Mass flow rates of 2, 2.5, 3, 3.5 LPM were observed alongside change in number of days for the experiment. The results show that the PTC with three passes receiver achieved higher average thermal efficiency and average useful energy than the PTC with smooth receiver

    Role of Some Nanoparticles in Certain Cardiovascular System Diseases. A Review

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    This paper gives a general overview of the many cardiovascular disorders and the therapy options that use certain nanoparticles. In order to provide tailored drug delivery to cardiovascular tissues and their biomarkers for treatment, it highlights and analyzes pertinent initiatives and advancements. The purpose of this review is to clarify the crucial and significant role that medication carriers based on nanoparticles play in the heart. This paper gives a general overview of the many cardiovascular disorders and the possible treatment options that make use of certain nanoparticles (silver, platinum, cadmium, and gold). In order to deliver tailored medications to cardiovascular tissues and associated biomarkers, it emphasizes and analyzes the pertinent efforts and advancements that have been made. We conclude that because of the qualities of nanoparticles and Nano carriers, like better target specificity and sensitivity, as well as passive and active targeting to heart tissue, the discipline of cardiology has been very interested in using them. Reportedly, nanotechnology can be used to efficiently treat a wide range of cardiovascular diseases

    Degradation of Indigo Dye Using Quantum Mechanical Calculations

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    The semiempirical (PM3) and DFT quantum mechanical methods were used to investigate the theoretical degradation of Indigo dye. The chemical reactivity of the Indigo dye was evaluated by comparing the potential energy stability of the mean bonds. Seven transition states were suggested and studied to estimate the actually starting step of the degradation reaction. The bond length and bond angle calculations indicate that the best active site in the Indigo dye molecule is at C10=C11.  The most possible transition states are examined for all suggested paths of Indigo dye degradation predicated on zero-point energy and imaginary frequency. The first starting step of the reaction mechanism is proposed. The change in enthalpy, Gibbs free energy and change in entropy of the overall reaction are equal to -548268.223 kcal/mol, 30831.951 kcal/mol and 48.552 cal/mol.deg, respectively. The activation energy is 46176.405 kcal/mol. The reaction rate is equal to

    Improving the melting performance in a triple-pipe latent heat storage system using hemispherical and quarter-spherical fins with a staggered arrangement

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    This study aims to evaluate the melting characteristics of a phase change material (PCM) in a latent heat storage system equipped with hemispherical and quarter-spherical fins. A vertical triple-pipe heat exchanger is used as the PCM-based heat storage unit to improve the melting performance compared with a double-pipe system. Furthermore, the fins are arranged in inline and staggered configurations to improve heat transfer performance. For the quarter-spherical fins, both upward and downward directions are examined. The results of the system equipped with novel fins are compared with those without fins. Moreover, a fin is added to the heat exchanger’s base to compensate for the natural convection effect at the bottom of the heat exchanger. Considering similar fin volumes, the results show that the system equipped with four hemispherical fins on the side walls and an added fin on the bottom wall has the best performance compared with the other cases with hemispherical fins. The staggered arrangement of the fins results in a higher heat transfer rate. The downward quarter-spherical fins with a staggered configuration show the highest performance among all the studied cases. Compared with the case without fins, the heat storage rate improves by almost 78% (from 35.6 to 63.5 W), reducing the melting time by 45%

    Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

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    Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Experimental Study for the Influence of Operating Parameters on Copper Electrorefining Process

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    Copper electrodeposition by electrorefining process in acidic sulfate media contains 40 g/l of cupric ions and 160 g/l of sulfuric acid was achieved to study the influence of the operating parameters on cathode purity, surface morphology, deposition rate, current efficiency and power consumption. These operating parameters and there ranges are: current density 200, 300 and 400 A/m2, electrolyte temperature 35, 50 and 65 oC, electrodes spacing 15, 30 and 45 mm and electrolyte residence time 6, 4 and 2 h were utilized. XRF, SEM and EDX analyses were attained to clarify the properties of the produced cathode

    Experimental Investigation and Computational Fluid Dynamic Simulation of Hydrodynamics of Liquid&ndash;Solid Fluidized Beds

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    The present study provides and examines an experimental and CFD simulation to predict and accurately quantify the individual phase holdup. The experimental findings demonstrated that the increase of solid beads has a significant influence on the (Umf), as comparatively small glass beads particles require a low (Umf) value, which tends to increase as the diameter of the beads increases. Besides that, the expansion ratio is proportional to the velocity of the liquid. Even though, the relationship becomes inversely proportional to the diameter of the beads. The liquid holdup was found to increase with increasing liquid velocity, however, the solid holdup decreased. The Eulerian&ndash;Eulerian granular multiphase flow technique was used to predict the overall performance of the liquid&ndash;solid fluidized beds (LSFBs). There was a good agreement between the experimental results and the dynamic properties of liquid&ndash;solid flows obtained from the CFD simulation, which will facilitate future simulation studies of liquid&ndash;solid fluidized beds. This work has further improved the understanding and knowledge of CFD simulation of such a system at different parameters. Furthermore, understanding the hydrodynamics features within the two-phase fluidization bed, as well as knowing the specific features, is essential for good system design, enabling the systems to perform more effectively

    Experimental Investigation and Computational Fluid Dynamic Simulation of Hydrodynamics of Liquid–Solid Fluidized Beds

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    The present study provides and examines an experimental and CFD simulation to predict and accurately quantify the individual phase holdup. The experimental findings demonstrated that the increase of solid beads has a significant influence on the (Umf), as comparatively small glass beads particles require a low (Umf) value, which tends to increase as the diameter of the beads increases. Besides that, the expansion ratio is proportional to the velocity of the liquid. Even though, the relationship becomes inversely proportional to the diameter of the beads. The liquid holdup was found to increase with increasing liquid velocity, however, the solid holdup decreased. The Eulerian–Eulerian granular multiphase flow technique was used to predict the overall performance of the liquid–solid fluidized beds (LSFBs). There was a good agreement between the experimental results and the dynamic properties of liquid–solid flows obtained from the CFD simulation, which will facilitate future simulation studies of liquid–solid fluidized beds. This work has further improved the understanding and knowledge of CFD simulation of such a system at different parameters. Furthermore, understanding the hydrodynamics features within the two-phase fluidization bed, as well as knowing the specific features, is essential for good system design, enabling the systems to perform more effectively
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