Evaluation of fire resistance of plastering applied to reinforced concrete

Concrete is one of the most resistant construction materials to heat and fire. It is known to retain heat for a relatively long time, thus limiting crack propagation from penetrating deeply. Furthermore, it can be repaired if exposed to fire for a limited time. However it loses its strength dramatically when exposed to elevated temperatures for long duration. With the increase in the use of concrete in structures, a demand arises to assess the fire resistance of concrete structural members and to develop means of improving the fire characteristics of these elements. One of the methods to increase the fire resistance of a building is to coat the structural elements with fire retardant plasters to delay failure. This work presents results of an experimental investigation aimed at evaluating the fire resistance of reinforced concrete columns coated with variable thicknesses of materials that has potential for fire resistance. Four types of coating materials were investigated namely; Perlite, Vermiculite, Rock wool, and conventional cement plaster. The tested columns had three various dimensions, four coating materials, and three coating thickness. Each column was loaded at half its working load and was simultaneously subjected to fire from four sides in a specially prepared furnace. The time needed to reach a specific temperature specified by ASTM-El19 and the post­fire strength were recorded. The results show the impact of the type of coating and column size on the fire resistance characteristics of the reinforced concrete columns in terms of time, and temperature. Relationships reflecting time-temperature correlation at the concrete surface and the coating thickness for each type are presented. On the whole, Perlite yielded superior results than the rest of the three coating materials with the conventional cement paste as the least effective fire protective coatings. The resistance to fire seems to enhance upon increasing coating thickness although de­bonding took place when applying large coat thickness. Further work needs to be conducted involving new materials and techniques, and involving micro-structural analysis of concrete and coating layers

COVID-19: The Potential Difference in High Resolution Computed Tomography Findings between Vaccinated and Unvaccinated Cases among The Adult Egyptian Population

Background: As the world experiences successive waves of corona virus disease (COVID-19) pandemic, global efforts to develop and distribute an effective vaccine produced several promising options. The aim of our study was to assess the difference in pulmonary involvement between vaccinated and unvaccinated patients among Egyptians.Patients and methods: Our study involved 234 patients who were tested positive for COVID-19 and had classic symptoms. They were split into 2 groups: group 1 (131 unvaccinated patients), and group 2 (103 fully vaccinated patients). Patients underwent high resolution computed tomography (HRCT) of the chest. All scans were evaluated, and CT severity score (CT-SS) was calculated.Results: For group 1 the patients’ ages ranged from 19 to 84, mean = 44.5 years (+ 16.2 SD), 76 (58%) males and 55 (42%) females, while group 2 age ranged from 18 to 85, mean (+SD)= 42.2 years (+ 16.6 ), 59 (57.3%) males and 44 (42.7%) females”. The presence of ground glass opacities and white lung sign varied significantly between both groups (P=0.001 and 0.002 respectively). For other recorded signs no significant difference was detected. The mean computed tomography severity score (CT-SS) for group 1 was 11.25 (± 6.6 SD). While for group 2 it was 6.32 (± 4.33 SD). The difference between studied groups was highly significant (P<0.001).Conclusion: Our results showed that COVID vaccine could effectively reduce the extent and severity of lung involvement in vaccinated patients compared with unvaccinated patients. Further wide-ranging clinical studies are needed to support our results

Distributed control for cooperative Parabolic systems with conjugation conditions

In this paper, we consider cooperative Parabolic systems defined on bounded, continuous and strictly Lipschitz domain of n R with conjugation conditions. We study the optimal control for these systems with Dirichlet conditions. Also, we establish the problem with Neumann conditions .The control in our problems is of distributed type

Distributed Control for Non-Cooperative Systems Under Conjugation Conditions

In this paper, the distributed control for non-cooperative elliptic systems under conjugation conditions is established. First, the existence and uniqueness of the state for these systems with Dirichlet and conjugation conditions is proved, then the set of equations and inequalities that characterizes the distributed control of these systems is found. The non-cooperative Neumann systems with conjugation conditions is also discussed

Investigating The Common Perceptual Qualities of Urban Morphology and Subjective Wellbeing Scales for Urban Mobility Studies: A Literature Review.

The impact of the built environment, urban form, and urban morphology on individual\u27s perception, experience and wellbeing has been the focus of many studies in the past few decades. Additionally, the impact of the built environment and its spatial characteristics has been recently studied from different approaches. Literature review shows that various research has been conducted on the impact of the built environment and travelers’ behavior and modal choice. However, few studies have been conducted on the impact of the built environment on travelers’ perception during mobility. Thus, this manuscript attempts to theoretically establish a link between the epistemology of urban form and morphology, urban mobility and transportation, and subjective wellbeing. A review of the body of literature on urban form, morphology and built environment is carried out. This to identify the main points related to subjective wellbeing which are listed by urban planning and design pioneers. In addition to reviewing literature on transportation, urban mobility, and travel behavior and its relationship with subjective wellbeing. This to highlight the main subjective wellbeing variables that are effective, as long as transportation and urban mobility is concerned. Afterwards, a review is conducted on the field of subjective wellbeing metrics, scales, and schedules. In which each scale is reviewed to identify the fields it was deployed in for further studies. The manuscript concludes by highlighting the subjective wellbeing scales that could be deployed in further studies related to urban form, morphology, built environment characteristics, and urban mobility. The findings could be deployed in further urban studies that target measuring subjective wellbeing in relation to the characteristics of the built environment

Comparison of endoscopic ultrasound guided 22-gauge core needle with standard 25-gauge fine-needle aspiration for diagnosing solid pancreatic lesions

Background and Objectives: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the standard modality for diagnosing pancreatic masses. We compared the diagnostic yield of a new EUS-guided 22-gauge core needle biopsy to a standard 25-gauge FNA in sampling the same pancreatic lesions during the same EUS. Patients and Methods: The main outcomes of the study were the sample adequacy of each method to provide a final pathological diagnosis, and the concordance in diagnosis between core and FNA specimens. The secondary outcomes were the sensitivity and specificity of the findings for each needle and the incremental yield of using both needles compared with using each needle alone. Results: A total of 56 patients with 61 solid pancreatic lesions were evaluated. The mean number of passes with FNA was 3.5 (ranges 1-8) and with core biopsy needle was 1.7 (ranges 1-5). The proportions of adequate samples were 50/61 (81.9%) for FNA and 45/61 (73.8%) for core biopsy (P = 0.37). The diagnostic yield was 46/61 (75.4%), 42/61 (68.9%) and 47/61 (77.1%) for FNA, core, and both, respectively. There was a substantial agreement of 87.5% ( = 0.77; P \u3c 0.001) in the findings of core and FNA specimens. The sensitivity for the diagnosis of malignancy for FNA and core biopsy were 68.1% and 59.6%, respectively (P = no significant [NS]). The specificity was 100% for both methods. The incremental increase in sensitivity and specificity by combining both methods are 1.5% and 0%, respectively. Conclusion: There are NS differences in the diagnostic yield between EUS-guided 22-gauge core biopsy and standard 25-gauge FNA for diagnosing pancreatic lesions, but core biopsy required fewer numbers of passes. There was NS incremental diagnostic yield when using both needles during the same procedure

Bioactive constituents and allelopathic activities of the invasive weed Ranunculus sceleratus L. Nile Delta, Egypt

Ranunculus sceleratus L. (celery-leaved buttercup) is a herbaceous plant grows in wet and moist habitats and is native to temperate and boreal North America and Eurasia. Moreover, it is listed as an invasive weed in northern Africa, Europe and Asia. This study aimed to determine some secondary products in R. sceleratus (Shoot and Root system) collected from canal banks of drains, Nile Delta, Egypt and to demonstrate their antioxidant and allelopathic potential. Results revealed that, methanolic extract of R. sceleratus rich in phenols, saponins and tannins. The antioxidant activity of the R. sceleratus has IC50 value of 0.37 mg/ml and 0.34 mg/ml for shoot and root, respectively, compared to 0.15 mg/ml for catechol. At 400 mg/ml, Chenopodium murale germination was inhibited by 79.74% and 92.64 for shoot and root extract, respectively, compared to control. However, the shoot growth was reduced by 76.06 % and 87.96 %, with the same sequence. The root growth was more sensitive to the allelopathic effect compared to the shoot, where it was inhibited by 82.68% and 98.67%, respectively, compared to control at the highest concentration. The obtained results on this invisive weed R. sceleratus could be a source of eco-friendly bioherbicides against C. murale and as a source of antioxidants