The progressive collapse behavior of precast floor-to-floor connections using longitudinal and transverse ties

This paper involves a fundamental study of a numerical method for progressive collapse resistance design of floor-to-floor joints in precast cross-wall structures. It presents a 3D numerical study of a floor-to-floor system with longitudinal and transverse ties. The model is also used to derive the post-bond behavior and the mechanism of forming catenary action concerning the bond behavior in precast cross-wall structures. The obtained results indicated the adequacy and applicability of the code specifications in British Standard, Euro Codes, and DoD 2013. Discrepancies in the tie-force between the numerical results and codified specifications have suggested an inappropriate use of the current TF method, hence, an improved model based on the numerical results has been proposed to address this concern. To the authors’ best knowledge, this is the first numerical study to investigate the behavior of floor-to-floor joints following the removal of wall support in typical precast cross-wall structures when considering bar fracture and pull-out failure mode

In vitro mineral nutrition of \u3ci\u3eCurcuma longa\u3c/i\u3e L. affects production of volatile compounds in rhizomes after transfer to the greenhouse

Background Turmeric is a rich source of bioactive compounds useful in both medicine and cuisine. Mineral concentrations effects (PO43−, Ca2+, Mg2+, and KNO3) were tested during in vitro rhizome development on the ex vitro content of volatile constituents in rhizomes after 6 months in the greenhouse. A response surface method (D-optimal criteria) was repeated in both high and low-input fertilizer treatments. Control plants were grown on Murashige and Skoog (MS) medium, acclimatized in the greenhouse and grown in the field. The volatile constituents were investigated by GC-MS. Results The total content of volatiles was affected by fertilizer treatments, and in vitro treatment with Ca2+ and KNO3; but PO43− and Mg2+ had no significant effect. The content was higher in the high-input fertilizer treatments (49.7 ± 9 mg/g DM) with 4 mM Ca2+, 60 mM KNO3 and 5 mM NH4+, than the low-input fertilizer (26.6 ± 9 mg/g DM), and the MS control (15.28 ± 2.7 mg/g DM; 3 mM Ca2+, 20 mM K+, 39 mM NO3−, 20 mM NH4+, 1.25 mM PO43−, and 1.5 mM Mg2+). The interaction of Ca2+ with KNO3affected curcumenol isomer I and II, germacrone, isocurcumenol, and β-elemenone content. Increasing in vitro phosphate concentration to 6.25 mM increased ex vitro neocurdione and methenolone contents. Conclusion These results show that minerals in the in vitro bioreactor medium during rhizome development affected biosynthesis of turmeric volatile components after transfer to the greenhouse six months later. The multi-factor design identified 1) nutrient regulation of specific components within unique phytochemical profile for Curcuma longa L. clone 35–1 and 2) the varied phytochemical profiles were maintained with integrity during the greenhouse growth in high fertility conditions

Whole Life Carbon Assessment of a Typical UK Residential Building Using Different Embodied Carbon Data Sources

The climate crisis in many sectors is driving rapid and substantial changes. Considering the fact that the building sector accounts for 39% of energy related carbon emissions, it is important to take swift actions to reduce these emissions. This study will identify the accuracy and availability of the embodied carbon databases. In this regard, the effect of using different embodied carbon databases on the total emissions during product and end-of-life stages will be compared. The results showed that using the UK Department for Business, Energy, and Industrial Strategy database (BEIS) overestimates the embodied carbon emissions. Additionally, using the Environmental product declarations database (EPDs), compared to the Inventory of Carbon and Energy database (ICE), can reduce embodied carbon for some materials up to 100%. The end-of-life calculation showed a huge difference between the two databases. In addition, Whole Life Carbon Assessment (WLC) has been carried out. The findings revealed that 67% of emissions come from operational carbon and embodied carbon is responsible for 33% of emissions. Using LED lights and installing PV panels can reduce the total CO2 emissions by 24.82 tonCO2. In addition, using recycled metal, less carbon intensive concrete, and recyclable aluminium can reduce the total CO2 emissions by 18.57, 2.07, and 2.3 tonCO2e, respectively

Whole Life Carbon Assessment of a Typical UK Residential Building Using Different Embodied Carbon Data Sources

The climate crisis in many sectors is driving rapid and substantial changes. Considering the fact that the building sector accounts for 39% of energy related carbon emissions, it is important to take swift actions to reduce these emissions. This study will identify the accuracy and availability of the embodied carbon databases. In this regard, the effect of using different embodied carbon databases on the total emissions during product and end-of-life stages will be compared. The results showed that using the UK Department for Business, Energy, and Industrial Strategy database (BEIS) overestimates the embodied carbon emissions. Additionally, using the Environmental product declarations database (EPDs), compared to the Inventory of Carbon and Energy database (ICE), can reduce embodied carbon for some materials up to 100%. The end-of-life calculation showed a huge difference between the two databases. In addition, Whole Life Carbon Assessment (WLC) has been carried out. The findings revealed that 67% of emissions come from operational carbon and embodied carbon is responsible for 33% of emissions. Using LED lights and installing PV panels can reduce the total CO2 emissions by 24.82 tonCO2. In addition, using recycled metal, less carbon intensive concrete, and recyclable aluminium can reduce the total CO2 emissions by 18.57, 2.07, and 2.3 tonCO2e, respectively

An improved tie force method for progressive collapse resistance

This paper involves a fundamental study of a numerical method for progressive collapse resistance design of floor-to-floor joint in the precast cross wall structures. It presents a 3D numerical study of floor-to-floor system with longitudinal and transverse ties. The model is also used to derive, the post-bond-behaviour and the mechanism of forming catenary action in relation to the bond behaviour in precast cross wall structures. The results obtained inform indicate the adequacy and applicability of the code specifications in British Standard, Euro Codes and DoD 2013. Discrepancies in the tie force between the numerical results and codified specifications have suggested that an inappropriate use of current TF method, hence improved model based on the numerical results has been proposed to address this concern. To the authors’ best knowledge, this is the first numerical study to investigate the behaviour of floor-to-floor joints following the removal of a wall support in typical precast cross wall structures when considering bar fracture and pull-out failure mode

Enhancing Sustainability of Low to Medium-Rise Reinforced Concrete Frame Buildings in the UK

In low-to-medium-rise RC frame buildings, to sustain gravity and lateral loads, mostly, two main load-bearing systems are used; moment-resisting (sway) and moment-resisting with shear walls. In the UK, the use of shear walls has now become an expansive technique in these types of RC frame building, as indicated by The Concrete Centre. Furthermore, considering the structural behaviour and performance of shear walls in low-to-medium-rise RC frame buildings, in the areas with low risk of seismic load they may negatively affect the economic and environmental efficiency of the construction without any substantial improvement to the structural performance of the building. In this study, several steps will be undertaken to enhance the sustainability of construction in RC frame buildings, including the possibility of removing shear walls in low-to-medium-rise buildings which can directly influence the consumption of aggregates (as natural resources) and cement in concrete and speed up the construction process. Reducing the amount of concrete in the construction of RC frames may be a feasible option that would have a significant effect on the reduction of CO2. emissions from the construction industry. The results indicate that, considering the practical side of the design, it is advisable to design the buildings up to 12 storeys using moment-resisting frame with flat slab. The results, also, shows 12% reduction of consumed concrete and 4.6% of CO2. emission in moment-resisting frames compared to the frame with shear walls. According to the outcome of this research and in collaboration with the Concrete Centre a design guide is developed for the use and implementation of moment-resisting frames in the UK construction industry

Review of battery management systems

In this work the authors investigate the different parts and functions offered by Battery Management Systems (BMS) specifically designed for secondary/rechargeable lithium batteries. Compared to other chemistries, lithium batteries offer high energy density and cell voltage, which makes them the most attractive choice for electronic devices including EV and RES. However, lithium technology is vulnerable and highly susceptible to catastrophic failures which result in fire. Hence, the use of electronic safety designs is a must. BMS are responsible for the monitoring of the battery state, ensuring operation within safe limits. BMS offer multiple functionalities with the state of charge (SoC) estimation being the most challenging hence the most studied by engineers. All estimation methodologies and algorithms have pros and cons, which best suits the application that is developed for. This research concludes that according to designers, the optimum BMS provides battery packs with the needed protection, good functioning conditions and accurate prediction for the battery's state including charge and life. Finally, this research presents and validates an SoC algorithm based on the reformulated Peukert's equation which is also valid for variable load and multi-pulsing scenarios with an accuracy exceeding 95%

Additional file 1: of In vitro mineral nutrition of Curcuma longa L. affects production of volatile compounds in rhizomes after transfer to the greenhouse

Turmeric volatile constituents data. (XLSX 26 kb

Mitigation of airborne contaminants dispersion in an educational building and investigate its impacts on indoor air quality and energy performance

In today's modern world, people spend most of their time inside buildings, highlighting the importance of indoor air quality (IAQ) and providing clean air to the occupants. In this regard, a simple educational building is modeled using CONTAM-EnergyPlus co-simulation to investigate IAQ enhancement strategies and their role in the building's energy performance. Three contaminants, including CO2, PM2.5, and SARS-CoV-2, are considered to be generated from various sources. The occupants generate CO2, a source of PM2.5 is assumed in the lunchroom to represent cooking activities, and a person who sheds SARS-CoV-2 moves around the zones. The main goal of this study is to apply various pollutant mitigation methods to the model, such as increasing ventilation rate and outdoor air (OA) percentage, natural ventilation, installing filters and air cleaners, and UVGI lights. Then, their performance and impact on the defined contaminants are studied individually and in combination. In this regard, a scenario with 80% outdoor air (OA) and 100% ventilation rate has been shown to be effective in reducing all three contaminants' concentrations to acceptable levels in most zones, but this results in 50% higher energy consumption compared to the model with no outdoor air. However, to achieve a safe level of PM2.5 in the lunchroom, a combination of all the strategies presented in the (0.8OA+1Vent+NatVent+all) scenario is required. Furthermore, HEPA air cleaners are more effective in diluting contaminants in all zones than UVGI lights and MERV 13 filters. Additionally, this study has shown that HVAC systems operating with little or no outside air can increase the risk of pollutants being transmitted between adjacent zones through the ducts, making it necessary to install in-duct filters

Multi-Zonal Analysis of Indoor Air Quality in a Higher Educational Building in the UK

This study focuses on the indoor air quality (IAQ) in a higher educational building, the London College in the UK. In this regard, indoor CO2 levels, as well as three contaminants with detrimental effects on human health: NO2, PM2.5, and SARS-CoV-2, are investigated. Various IAQ enhancement strategies are analyzed, including increased ventilation, background ventilation, improved airflow through opened doors, and the use of HEPA air cleaners. Results revealed that background ventilation and open doors during occupied periods reduced CO2 concentrations to around 1000 ppm. However, the effectiveness of background ventilation was influenced by outdoor conditions, such as wind speed and direction. The most effective method for reducing PM2.5 levels was installing an air cleaner alongside a commercial kitchen hood, resulting in a 15% greater reduction compared to background ventilation. To control the SARS-CoV-2 level, combining background ventilation or opening the doors with a 16,000 m3/h ventilation rate or using an air cleaner with baseline ventilation resulted in a basic reproductive number below 1. Overall, the research highlights the importance of background ventilation and open doors in enclosed spaces without operable windows for natural airflow. Additionally, the effectiveness of air purifiers in reducing particle and biological contaminant concentrations is demonstrated, providing valuable insights for improving IAQ in educational buildings