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The present work addresses conducting an experimental comparison between different types and dosages of fibers and nanomaterials in compressive tests and the cost of mixes for high-strength concrete (HSC). This study investigated the materials used in the construction sector in Egypt. The experimental work was carried out to select the optimum percentage of each type of the used nanomaterials, and fibers to achieve the highest compressive strength and low cost. In this work, nineteen concrete mixes were prepared. Nano silica (NS) and nano clay (NC) were used at 0, 1, 2, and 3 % by weight of cement. Also, nano- fumed silica (FS) was used at 0, 1, 2, 3, 5, and 10 %, while silica fume (SF) was used at 10 % by weight of cement. Each type of corrugated round steel fiber (STF), and polypropylene fibers (PPF) were used at 0.5, 0.75, and 1.00 % by concrete volume. The results indicated that the compressive strength of the HSC increases as the percentage of adding nano-fumed silica increases up to 3 % and the economic feasibility of nano-fumed silica in concrete is better than in other nanomaterials such as nano silica and nano clay. Also, using 1 % steel fiber in HSC increases concrete strength significantly compared to conventional concrete without considerably increasing the cost.

The coronavirus disease (COVID-19) presented a unique opportunity for the World Health Organization (WHO) to utilise public health intelligence (PHI) for pandemic response. WHO systematically captured mainly unstructured information (e.g. media articles, listservs, community-based reporting) for public health intelligence purposes. WHO used the Epidemic Intelligence from Open Sources (EIOS) system as one of the information sources for PHI. The processes and scope for PHI were adapted as the pandemic evolved and tailored to regional response needs. During the early months of the pandemic, media monitoring complemented official case and death reporting through the International Health Regulations mechanism and triggered alerts. As the pandemic evolved, PHI activities prioritised identifying epidemiological trends to supplement the information available through indicator-based surveillance reported to WHO. The PHI scope evolved over time to include vaccine introduction, emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, unusual clinical manifestations and upsurges in cases, hospitalisation and death incidences at subnational levels. Triaging the unprecedented high volume of information challenged surveillance activities but was managed by collaborative information sharing. The evolution of PHI activities using multiple sources in WHO’s response to the COVID-19 pandemic illustrates the future directions in which PHI methodologies could be developed and used.

In assembly line balancing problems, time is balanced among workers. This does not necessarily balance their physical effort. The effort exerted by workers varies depending on the type of the job, and the size and weight of the component. In the two-sided assembly lines, commonly used for heavy industries, the variation in physical effort among workers is more emphasized. The unbalanced effort leads to fatigue, and may lower productivity and quality. This work aims at balancing the physical effort among workers in the two-sided assembly lines, while considering other conventional objectives. A genetic algorithm and a new decoding scheme are proposed. An effort smoothness index (ESI) is introduced to measure the variation in effort among workers. Results prove that balancing the physical effort is influential and can be achieved at no extra cost for most cases. Effort balancing is harder to achieve in difficult problems; of high order of strength.

Event-based surveillance (EBS) is the organised approach to the detection and reporting of ‘signals,’ defined as information that may represent events of public health importance, often through channels outside of routine surveillance systems. Signals can be designed to detect patterns of disease, such as clusters of similar illness in a community, or clusters of disease or death in animals. Signals can also include single cases of suspected high-priority events such a patient with viral haemorrhagic fever. EBS can be a key component of an effective early warning system, which enables countries to be better prepared for endemic and pandemic illness outbreaks. EBS uses an all-hazards approach that includes the principles of One Health. This review covers the concept and process of EBS, different sources for EBS data, and methods to obtain information from these sources. This overview will aid countries in implementing this important form of surveillance.

Background: Since the first case of COVID-19 in Sudan was reported in March 2020, the Federal Ministry of Health adopted an active surveillance system to collect and analyze information from the isolation centers and public and private laboratories about all suspected and confirmed COVID-19 cases. This study used the surveillance data to better understand the distribution and determinants of COVID-19 in Sudan and to construct a threshold level beyond which the dramatic surge may occur. Methods: Data of suspected and confirmed COVID-19 cases were extracted from the line list prepared by the Surveillance and Information Department at the Federal Ministry of Health after obtaining ethical approval from the National Ethics Committee. Data were cleaned, coded, and analyzed using SPSS version 21. Frequencies and proportions were used to describe data. A univariate logistic regression analysis was used to determine the association of variables with the positivity of COVID-19. Variables with p-values p Results: Out of 48,545 suspected cases, 27,453 were positive. Four waves were seen, with a distinct explosion point of around 200 cases observed nationwide. Khartoum reported the highest number of cases. Of those tested positive, 16,444 (59.9%) were male and 11,009 (40.1%) were female. The mean (SD) age of cases was 41.1 (19.0) years with 21.6% of cases above 60 years. 14,780 (53.8%) of cases were asymptomatic. Fever, cough, shortness of breath, and loss of smell and taste were reported in 32.7%, 26.4%, 19.1 and 4.5% of confirmed cases, respectively. A total of 1,793 confirmed cases died; the case fatality rate was 6.5%. A considerable proportion of infection was reported among health workers. A univariate logistic regression analysis revealed that being symptomatic is significantly associated with testing negative for COVID-19 (odds ratio < 1). Conclusions: COVID-19 was widely spread in Sudan with more cases in Khartoum, the capital of Sudan. The country experienced four waves with an observable epidemic explosion point of around 200 positive cases per week nationwide. Around half of the patients were asymptomatic; however, fever, cough, and shortness of breath were the commonest symptoms. The CFR all through was 6.5%, with death having a strong association with age. Further studies are recommended to clarify the image, especially among health workers. The study also highlighted the need to improve the quality of surveillance data.

In April 2020, the Ministry of Health (MoH) in Oman, a high-income country in the Eastern Mediterranean Region (EMR), implemented a robust contact tracing (CT) system for COVID-19. To capitalise on Oman’s experience, EMRO has developed a case study presenting the methodology used to conduct the CT activities, main functions of the system, challenges encountered, lessons learnt, and the way forward. To develop the case study, a key informant interview was conducted virtually with the CT focal point in the MoH, using a semistructured questionnaire adapted from the WHO questionnaire for the assessment of CT activities. The Oman MoH launched a CT system based on three complementary digital tools: Tarassud plus, Medical Scout and HMushrif applications. Oman’s CT strategy classifies contacts into close and casual contacts. Only close contacts are listed using the Tarassud plus application, while casual contacts are requested to self-monitor for 14 days using the other two applications. With the evolution of the outbreak, Oman MoH implemented stricter policies and prioritised the follow-up of close contacts to keep the CT activity manageable. Community health workers and volunteers facilitated the CT activities through sensitisation of the local community to the follow-up process and reducing the COVID-19-associated stigma. Challenges encountered revolved around contact data management, given the offline in-operability of the applications, and lack of national risk communication guidelines to address community concerns and widespread rumours.

Although supply chain disruptions have been under study since the 1990’s, they attracted more attention last year due to the COVID-19 pandemic. Not only researchers, but all people realized how disruptions can negatively affect the performance of business, and supply chains. Mitigation strategies are the way to “be better prepared” for such disruptions. This paper aims at evaluating the performance of five different mitigation strategies for a multi-period supply chain under operational disruptions. The disruptions under consideration are capacity, and demand disruptions, whether separate or simultaneous. Integer linear programming is used to design the supply chain network. Monte Carlo simulation is used to evaluate the performance of the proposed mitigation strategies under different disruption scenarios. Results reveal that the mitigation strategies that perform better regarding financial performance measures, perform worse regarding customer satisfaction performance measures. The model helps decision makers to decide the most suitable mitigation strategy according to their priorities.

Two sided assembly lines are used for large sized products where assembly tasks are performed by two workers on both sides. Multi-manned lines are mainly used in the assembly of relatively large products, with a number of workers moving around the product performing assembly tasks. This movement may lead to interference and congestion of man and material. In this paper a new line configuration is investigated by combining the two types of lines in what is designated as Two-Sided Multi-Manned (TSMM) assembly line. The proposed configuration benefits from the advantages of both lines by proposing four workers; two on each side, avoiding interference of the work and reducing the assembly stations.A model based on genetic algorithm was developed to balance the proposed TSMM line under the objectives of minimizing the number of workers and the number of mated-stations. A new method for generating the initial population is proposed leading to remarkably faster convergence of the solution. A controlling parameter is introduced to enable the tradeoff between the number of workers and the number of mated stations, adding flexibility to the line design. Results reveal that the proposed model gives competitive results to genetic algorithm and particle swarm optimization in the two-sided assembly line benchmark problems. It converges to a final solution in considerably less number of iterations. The application of the TSMM line concept results in considerable reduction in the number of mated stations with space saving up to 50% for the same number of workers.

Background Cerebrovascular accidents and cognitive impairment is a frequent complication of end-stage renal disease (ESRD) on regular hemodialysis (HD). Objective To evaluate cerebral circulation hemodynamics in non-diabetic prevalent hemodialysis patients by transcranial Doppler (TCD). Patients and methods The cross-sectional study included 50 ESRD patients on regular hemodialysis > 6 months in Ain Shams University Hospitals, Cairo, Egypt. Diabetic patients; chronic liver disease patients Child-Pugh class B or C; smokers; history of evident of cardiac, peripheral, or cerebrovascular insult; uncontrolled hypertension; anemia; collagen disease; and active infection were excluded from the study. An assessment of cerebral circulation hemodynamics by TCD in non-dialysis day to examine mean flow velocity (MFV) in the middle cerebral artery (MCA) and posterior cerebral artery (PCA). Results An assessment of cerebral circulation hemodynamics revealed that 16 (32%) of the patients showed decrease MFV in MCA and 30 (60%) were normal. Regarding MFVs in PCA, 13 (26%) of the patients showed decrease MFVs, 33 (66%) were normal, and 4 (8%) of the patients failed due to poor bone window, significant reduction of MCV and PCA velocities in HD with urea reduction ratio < 65%, and a significantly negative correlation of MFV, PCA, and hemoglobin level (P < 0.05). Conclusion There is a high frequency rate of decreased MCA and PCA MFV (32%, 28%), respectively, among non-diabetic prevalent hemodialysis patients with significant correlation to hemodialysis adequacy.

This paper studies the rescheduling problem of a single machine facing unexpected disruptions in order to determine which parameters can help reducing the negative impacts of these disruptions on schedule performance. A Genetic Algorithm (GA) is used to generate the initial schedule and the updated ones according to a reactive strategy. The performance of event-driven rescheduling and periodic rescheduling policies are compared in terms of total tardiness and total cost of rescheduling. Other factors that may affect rescheduling such as disruption time, disruption duration and number of disruptions are investigated. The sensitivity of results to both due date tightness and cost factor variation is tested. The results showed that the timing of the occurrence of disruption as related to scheduling horizon has a major effect on determining the best rescheduling policy. Event-driven policy is superior to other policies for short infrequent disruptions. It was found that the periodic policy is more appropriate for long and frequent disruptions.

The objective of this paper is to establish a detailed map for the temporal instability of the bottom boundary layer (BBL) flow driven by a soliton-like wave induced pressure gradient in a U-tube-shaped tunnel, which serves as an approximation to the BBL under surface solitary waves. Both linear stability analysis and fully nonlinear two-dimensional simulations using high-order numerical methods have been carried out. The process of delineation of the stability regions as a function of boundary layer thickness-based Reynolds number of the temporally evolving base flow, Reδ, consists of two parts. In the first part, we assess the lower limit of the Reδ range within which the standard, quasi-steady, linear stability analysis is applicable when considering individual base flow profiles sampled during its transient evolution. Below this limit, transient linear stability analysis serves as a more accurate predictor of the stability properties of the base flow. In the second step, above the Reδ limit where the ...

Two-sided assembly lines are common industrial practice in the assembly of large-sized products. In this paper a Genetic Algorithm (GA) is developed to solve the two-sided assembly line balancing problem. The developed GA specifies a new method for generating the initial population. It applies a hybrid crossover and a modified scramble mutation operators. A proposed station oriented procedure is adopted for assigning tasks to mated-stations. It specifies the side of the Either tasks based on proposed side assignment rules rather than assigning them randomly. These rules are effective especially in large problems. The proposed method of generating the initial population is able to generate feasible solution in different areas of the search space. The applied genetic operators are able to preserve the feasibility of all solutions throughout all the developed generations. The proposed GA is able to find the optimum and near optimum solutions within a limited number of iterations.