Designing a large scale solar PV system and impact analysis of its integration into Sudan power grid

The increasing energy demand and the development of renewable energy technology present a new possibility to implement renewable energy sources. Sudanese people have been suffering from electricity outage due to the price fluctuation in fuel resources. Unfortunately, Renewable energy power plant can cause a huge implication of grid. Many considerations should be considered to study the voltage drop and load flow analysis as well. Solar energy is the most prominent among renewable sources, as it is an inexhaustible resource and its exploitation has thus far been ecologically friendly. The aim of this project is to simulate and analyse a large-scale grid connected photovoltaic system is designed with 100 MW installed capacity. Details of the design include the total number of PV modules, inverter, cables and substation. In this study, the main system design is undertaken based on the amount of generated power. The generated output power from the PV system is at 0.8 kV voltage level. Then it connected to several transformers. The project site is at the desert in Khartoum, Sudan. The output of the power transformer is synchronized to the national grid at Khartoum substation less than 100 m of the supply point. To achieve the power ratings, 397 inverters has been designed with 24 string for each resulting at 100 MW generated power were adopted. This project used PVsyst software for energy production and ETAP software for the substation design

Adaptive control using variable structure systems.

Adaptive control is employed in control systems required to operate satisfactorily regardless of parameter variations, external disturbances and changes in the environment. A conceptually simple approach to adaptive control is the model reference approach which yields a nonlinear feedback system. In a model reference control system the system output is made to follow the output of a specified model. There are numerous approaches to the design of model reference adaptive control systems (MRAC). In this thesis the theory of variable structure systems (VSS) is studied and applied in the design of MRAC systems. VSS are inherently nonlinear feedback systems which exhibit certain adaptive properties including insensitivity to a range of parameter variations and certain external disturbances when operating in the sliding mode. The application of VSS theory to the problem of adaptive model-following has demonstrated the simplicity of the design. It also ensures the asymptotic stability of the controlled system and provides direct control over the error transient. The notion of system zeros arises naturally when tackling the problem of output model-following control systems. Certain interrelations between VSS, system zeros and the output model following problem have suggested a new method for computing the zeros of linear multivariable square systems. A fundamental operator in VSS is shown to be a projector. The employment of projector theory in the study of VSS provides further insight into their operation. Furthermore new methods for constructing the switching hyperplanes matrix are formulated by utilizing projector theory. The linear control law ensuring output model-following and the necessary order reduction is shown to be identical to the equivalent control encountered in VSS. The control law also decouples the system, assigns arbitrary poles and possesses certain adaptive properties. The extension of VSS theory to output model following systems using output information is also discussed

A Proposed IoT-Based Bike Sharing System in Erbil City

urrently, many countries are faced with many problems regarding the environment and the destruction to the planet’s natural resources. In the long run, this will have a devastating effect on the well-being of mankind. As technology advances, and cities become over-populated, the damaging effects of air pollution, noise pollution, carbon monoxide from machinery and overcrowding could very well destroy the planet if countries don’t take measures to minimise this damage, and focus on boosting biodiversity and fighting climate change, thereby making the city a healthier place for everyone. Many countries have implemented the bike sharing system to solve some of the problems caused by mechanised transportation. In this paper, an IoT-based bike sharing docked system is proposed for the city of Erbil. This proposal has looked at expected challenges and solutions

Acute toxicity and antihyperglycaemic effect of ethanol stem-bark extract of Annona senegalensis Pers. (Annonaceae) on alloxan induced diabetic rats

Background: Diabetes is a common and very prevalent disease affecting the citizens of both developed and developing countries. Many oral hypoglycaemic agents available for the treatment have significant side effects and sometimes are found to be ineffective in chronic diabetic patients. Objective: To study the acute toxicity and effect of the ethanol stem-bark extract of Annona senegalensis on blood glucose in alloxan-induced diabetic rats. Material and Methods: Hypoglycaemic effect of the extract was studied in normal rats using oral glucose tolerance test and in alloxan-induced diabetic rats. Effects of 100, 200 and 300 mg/kg, i.p of ethanol stem-bark extract of Annona senegalensis, and glibenclamide (5 mg/kg, i.p) were studied on blood glucose. Results: The median lethal dose of the extract was found to be 1131.4 mg/kg by intraperitoneal route. In the normal rats (OGTT), from basal to 0 min, the extract did not show significant reduction in the fasting serum glucose level. However, the extract at 300 mg/kg and glibenclamide (5 mg/kg) significantly (p≤ 0.05) prevented glucose induced hyperglycemia at 30 to 90 min as compared to normal control. In the alloxan-induced diabetic rats, 100, 200 and 300 mg/kg of the extract produced significant (p≤0.05) reduction in blood glucose levels. Maximum effect was observed with the 300 mg/kg dose of stem-bark of Annona senegalensis. Conclusion: The results showed that the ethanol extract of the stem bark of the plant possessed antihyperglycaemic activity. Key Words: Hypoglacaemic effect, Annona senegalensis, diabetes mellitus, glibenclamide

SRPTackle: A semi-automated requirements prioritisation technique for scalable requirements of software system projects

ContextRequirement prioritisation (RP) is often used to select the most important system requirements as perceived by system stakeholders. RP plays a vital role in ensuring the development of a quality system with defined constraints. However, a closer look at existing RP techniques reveals that these techniques suffer from some key challenges, such as scalability, lack of quantification, insufficient prioritisation of participating stakeholders, overreliance on the participation of professional expertise, lack of automation and excessive time consumption. These key challenges serve as the motivation for the present research.ObjectiveThis study aims to propose a new semiautomated scalable prioritisation technique called ‘SRPTackle’ to address the key challenges.MethodSRPTackle provides a semiautomated process based on a combination of a constructed requirement priority value formulation function using a multi-criteria decision-making method (i.e. weighted sum model), clustering algorithms (K-means and K-means++) and a binary search tree to minimise the need for expert involvement and increase efficiency. The effectiveness of SRPTackle is assessed by conducting seven experiments using a benchmark dataset from a large actual software project.ResultsExperiment results reveal that SRPTackle can obtain 93.0% and 94.65% as minimum and maximum accuracy percentages, respectively. These values are better than those of alternative techniques. The findings also demonstrate the capability of SRPTackle to prioritise large-scale requirements with reduced time consumption and its effectiveness in addressing the key challenges in comparison with other techniques.ConclusionWith the time effectiveness, ability to scale well with numerous requirements, automation and clear implementation guidelines of SRPTackle, project managers can perform RP for large-scale requirements in a proper manner, without necessitating an extensive amount of effort (e.g. tedious manual processes, need for the involvement of experts and time workload)

Review of the Nanostructuring and Doping Strategies for High-Performance ZnO Thermoelectric Materials

Unique properties of thermoelectric materials enable the conversion of waste heat to electrical energies. Among the reported materials, Zinc oxide (ZnO) gained attention due to its superior thermoelectric performance. In this review, we attempt to oversee the approaches to improve the thermoelectric properties of ZnO, where nanostructuring and doping methods will be assessed. The outcomes of the reviewed studies are analysed and benchmarked to obtain a preliminary understanding of the parameters involved in improving the thermoelectric properties of Zn

Photo-electrochemically synthesized light emtting nanoporous silicon based UV photodetector: influence of current density

Nanoporous silicon (n-PSi) with diverse morphologies was prepared on silicon (Si) substrate via photo-electrochemical etching technique. The role of changing current density (15, 30 and 45 mA cm−2) on the structure, morphology and optical properties was determined. As-prepared samples were systematically characterized using XRD, FESEM, AFM and photoluminescence measurements. Furthermore, the achieved n-PSi sample was used to make metal–semiconductor–metal (MSM) UV photodetector. The performance of these photodetectors was evaluated upon exposing to visible light of wavelength 530 nm (power density 1.55 mW cm−2), which exhibited very high sensitivity of 150.26 with a low dark current. The achieved internal photoconductive gain was 2.50, the photoresponse peak was 1.23 A W−1 and the response time was 0.49 s and the recovery time was 0.47 s. Excellent attributes of the fabricated photodetectors suggest that the present approach may provide a cost effective and simple way to obtain n-PSi suitable for sundry applications

Development of low absorption and high-resistant sodium acetate concrete for severe environmental conditions

This research presents new insight on the performance of concrete when integrated with sodium acetateand cured under extremely harsh environmental conditions: freezing temperature of 25°C and hottemperature of 60°C. Mechanical properties, water absorption, microstructural analysis and interactionmechanism of concrete and sodium acetate were evaluated by conducting the compressive strength test,Initial Surface Absorption Test (ISAT), Scanning Electron Microscope (SEM) analysis and Fourier-transform Infrared Spectroscopy (FTIR) analysis. Despite the harsh curing conditions, results showedan enhancement of 64% in compressive strength when 4% (based on the weight of cement) sodium acet-ate is incorporated within concrete with w/c ratio of 0.32 and cured under temperature of 60°C. Also,water absorption was observed to decrease by more than 79% when 2% sodium acetate is added to con-crete with w/c ratio of 0.32. SEM and FTIR analyses revealed the formation, high distribution and strongbonding of sodium acetate crystals within the concrete’s micropores

Epidemiology, diagnostics and factors associated with mortality during a cholera epidemic in Nigeria, October 2020-October 2021: a retrospective analysis of national surveillance data.

OBJECTIVES: Nigeria reported an upsurge in cholera cases in October 2020, which then transitioned into a large, disseminated epidemic for most of 2021. This study aimed to describe the epidemiology, diagnostic performance of rapid diagnostic test (RDT) kits and the factors associated with mortality during the epidemic. DESIGN: A retrospective analysis of national surveillance data. SETTING: 33 of 37 states (including the Federal Capital Territory) in Nigeria. PARTICIPANTS: Persons who met cholera case definition (a person of any age with acute watery diarrhoea, with or without vomiting) between October 2020 and October 2021 within the Nigeria Centre for Disease Control surveillance data. OUTCOME MEASURES: Attack rate (AR; per 100 000 persons), case fatality rate (CFR; %) and accuracy of RDT performance compared with culture using area under the receiver operating characteristic curve (AUROC). Additionally, individual factors associated with cholera deaths and hospitalisation were presented as adjusted OR with 95% CIs. RESULTS: Overall, 93 598 cholera cases and 3298 deaths (CFR: 3.5%) were reported across 33 of 37 states in Nigeria within the study period. The proportions of cholera cases were higher in men aged 5-14 years and women aged 25-44 years. The overall AR was 46.5 per 100 000 persons. The North-West region recorded the highest AR with 102 per 100 000. Older age, male gender, residency in the North-Central region and severe dehydration significantly increased the odds of cholera deaths. The cholera RDT had excellent diagnostic accuracy (AUROC=0.91; 95% CI 0.87 to 0.96). CONCLUSIONS: Cholera remains a serious public health threat in Nigeria with a high mortality rate. Thus, we recommend making RDT kits more widely accessible for improved surveillance and prompt case management across the country

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

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