Effects of recycled tyre rubber and steel fibre on the impact resistance of slag-based self-compacting alkali-activated concrete

Accumulation of waste tyres causes an environmental disaster because of the rapid rise in transport vehicle demand resulting from modern developments, Covid-19 and similar pandemics. Thus, recycling waste tyres in the form of aggregates as a sustainable construction material can be a solution to reduce the environmental problems. Current research focuses on the impact resistance and mechanical properties of the crumb rubber self-compacting alkali-activated concrete reinforced with 1% steel fibres (SFs) where fine and coarse crumb rubbers (CR) are partially replaced with 10% and 15% replacement ratios. The compressive, flexural, splitting tensile strengths and modulus of elasticity were investigated;impact resistance was found using a drop hammer impact test. The incorporation of CR reduced the mechanical properties, and the reduction was found more with increased rubber contents, whereas the incorporation of SF compensated for the strength loss. The impact performance was enhanced with the CR and SF incorporations. The 15% CR incorporation improved the impact energy up to three times, whereas both 1% SF and 15% CR incorporations significantly enhanced the impact energy up to 30 times. Similar mechanical strengths were obtained for the different sizes of CR. However, impact performance was significantly influenced by the sizes of CR. © 2022 Informa UK Limited, trading as Taylor & Francis Group.

Design of Steel Intensive Quarantine Centre

In pandemic conditions, where the COVID-19 infection is increasing exponentially, quarantine centres have become very necessary to separate and restrict the movement of people. These structures are also helpful in similar situations like disaster management, defence purposes and housing for poor people. Planning and Designing of Steel Intensive Quarantine Centre' takes on the task of designing and analysing an economical, ecological and rapid construction solution of a modular quarantine centre building. It facilitates a faster construction facility due to steel construction instead of RCC, which takes almost 70–80% more time and is not recyclable like steel. The schematic and elevation plans have been tweaked with additional architectural features to ensure ventilation, sunlight and accessible transit of patients. For economical structural design, the iterative method is incorporated to find columns with the minimum size and shape to achieve ample carpet area, i.e., star-shaped. While designing the structures, i.e., portal frame and truss roof frame are subjected to the same loading conditions. For resisting the lateral forces, different types of bracings have been incorporated in plan and elevation. The construction of a portal frame requires specialized labour to handle compound sections and connections, whereas construction of truss sections is possible by skilled labour or directly use prefabricated truss sections with the help of unskilled labour. Compound sections pose a significant challenge due to their unavailability and transportation difficulties. In contrast, the sections for trusses are readily available even in the remote market. Moreover, the construction of both structures provides rapid construction. The portal frame costs about 16% cheaper than the steel frame due to smaller sections and absence of compound sections. For validation of our work, we have used manual and automated calculation to minimize the error. The structure is expandable for future expansion by techniques such as expansion joint and satellite arrangement. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

[Educating to properly close the toilet knob taps or to replace them]. / Educare a chiudere in modo corretto i rubinetti a manopola del bagno o a sostituirli.

Systematic reviews have shown a prevalence close to 20% of gastrointestinal symptoms in COVID-19 positive patients, with nearly 40% of patients shedding viral RNA in their faeces, even if it may not be infectious, possibly because of inactivation by colonic fluid.According to current evidence, this virus is primarily transmitted by respiratory droplets and contact routes, including contaminated surfaces. The virus is quite stable on stainless steel, being detected up to 48-72 hours after application. Therefore, some individuals can be infected touching common contaminated surfaces, such as bathroom taps. Taps can be underestimated critical points in the transmission chain of the infection. Indeed, just by turning the knob, people leave germs on it, especially after coughing over their hands, sneezing, and/or blowing their nose. After handwashing with soap, user take back their germs when turning the knob. Paradoxically, the following user collects the germs back on his/her fingers by implementing a preventive measure, maybe before putting food into the mouth or wearing contact lenses.The Italian National Institute of Health recommends to clean and disinfect high-touched surfaces, but it is unrealistic and inefficient to do so after each tap use. As an alternative, new toilets should install long elbow-levers - or at least short levers - provided that people are educated to close them with the forearm or the side of the hand. This is already a standard measure in hospitals, but it is particularly important also in high-risk communities, such as retirement homes and prisons. It would be important also in schools, in workplaces, and even in families, contributing to the prevention both of orofaecal and respiratory infections.In the meantime, people should be educated to close existing knobs with disposable paper towel wipes or with toilet paper sheets.

Method validation for the recovery of the porcine respiratory and reproductive syndrome virus, a potential SARS-CoV-2 surrogate, from stainless steel.

Virus survival on fomites may represent a vehicle for transmission to humans. This study was conducted to optimize and validate a recovery method for the porcine respiratory and reproductive syndrome virus (PRRSV), a potential SARS-CoV-2 surrogate, from stainless steel. Coupons (1.5 × 1.5 cm) inoculated with ca. 7 logs TCID50 of PRRSV were dried for 15 min at room temperature, followed by incubation at 4°C and 35% relative humidity. After 1 h and 24 h, the coupons were processed by four different methods: vortex in DMEM media, vortex in DMEM media with beads, vortex in elution buffer, and shake in elution buffer. The rinsates were processed for titration using the TCID50 method in the MARC-145 cell line. All four methods were equally effective to recover the virus from the soiled SS surfaces (> 79% recovery). The amount of infectious virus recovered after 24 h was similar (P > 0.05) to that recovered after 1 h, indicating that the virus was stable at 4°C for up to 24 h. Using an elution buffer followed by shaking was the least labor-intensive and most economical method. Therefore, this method will be used for future experiments on PRRSV survival and transfer from food-contact surfaces.

Surface Inactivation of a SARS-CoV-2 Surrogate with Hypochlorous Acid is Impacted by Surface Type, Contact Time, Inoculum Matrix, and Concentration.

Indirect contact with contaminated surfaces is a potential transmission route for COVID-19. Therefore, it is necessary to investigate convenient and inexpensive surface sanitization methods, such as HOCl, against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 surrogate, Phi6 (~ 7 log PFU/mL), was prepared in artificial saliva and tripartite matrices, spot inoculated on coupons of either stainless steel or vinyl, and allowed to dry. The coupons were sprayed with either 500 ppm or 1000 ppm HOCl, and remained on the surface for 0 s (control), 5 s, 30 s, or 60 s. Samples were enumerated via the double agar overlay assay. Statistical analysis was completed in R using a generalized linear model with Quasipoisson error approximations. Time, concentration, surface type, and inoculum matrix were all significant contributors to log reduction at P = 0.05. Significant three-way interactions were observed for 1000 ppm, vinyl, and 60 s (P = 0.03) and 1000 ppm, tripartite, and 60 s (P = 0.0121). A significant two-way interaction between vinyl and 60 s was also observed (P = 0.0168). Overall, increased HOCl concentration and exposure time led to increased Phi6 reduction. Notably, the highest estimated mean log reduction was 3.31 (95% CI 3.14, 3.49) for stainless steel at 60 s and 1000 ppm HOCl in artificial saliva, indicating that this method of sanitization may not adequately reduce enveloped viruses to below infective thresholds.