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Impact of mechanical elements may have the devastating effects including the material breakdown, abnormal deformation, stiffness lowering and the surface wear. In the present study it is showed that covering the impacted targets by the fluid layer will accommodate these effects by absorbing a portion of the impact energy.

In the present work, a drop test machine is used to experimentally investigate the effect of influencing parameters on the impact subsequences. Effect of the impact velocity, incidence angle, ball size, target bed and covering oil/water layer is considered.

Testing the variety of the oil layers thickness revealed that the large portion of the impact energy can be damped by thickening the covering fluid. The ratio of the energy absorbed by the same thickness oil and water layer is extracted. Results show that the energy absorbed by the water layer is lower than half of the energy absorbed by the oil layer in several cases. Moreover, theoretical relations are extracted from the experimental data which give the energy absorption by rubber bed contrast to the steel bed and also the energy absorption by fluid layer contrast to the dry impact.

This paper includes investigating the effect of specimen bed and covering fluid layer on energy absorption by a new experimental apparatus. Layers of oil and water have been compared.

This paper aims to apply frame analysis to explore the mental models by which building managers interpret the impact of building occupants on energy use and rationalize their approach to occupant engagement.

Findings from four energy-efficient buildings (two schools and two office buildings) in Norway are presented. The methodology includes individual semi-structured interviews with both operational and strategic facilities managers

Concepts and theoretical perspectives with the potential to shape the building managers’ perceptions include technical knowledge and expertise, management responsibilities, familiarity with occupant routines and understanding of energy-efficient technologies. No significant impact was attributed to the actions of occupants in the areas of comfort, core function and behavior. Significant impact was attributed to their movement and presence. Perceptions of impact were found to influence, yet not determine, the building managers’ choices of practice.

Factors with the potential to affect the adoption of occupant engagement initiatives were highlighted. This study pointed to the role that automation and centralization can play in influencing facilities managers to rescind from their management responsibilities.

To the knowledge of the authors, this is the first study to use framings in thoughts to investigate the process by which facilities managers rationalize occupant engagement, in relation to their perception of occupant impact on energy use.

The purpose of this paper is to identify the energy absorption characteristics of arch micro-strut (ARCH) lattice structure (different from traditional straight micro-strut lattice structure) under high-speed impact, and promote the development of special-shaped micro-strut lattice structure.

The study serves to study the anti-impact and energy absorption characteristics of ARCH lattice structure under different strain rates and different unit layers of lattice structure. In this paper, quasi-static compression and Hopkinson compression bar experiments are used for comparative analysis.

The results show that the ARCH lattice structure has obvious strain rate effect. When the strain rate is low, the number of layers of lattice structure has a great influence on the mechanical properties. With the increase of strain rate, the influence of the number of layers on the mechanical properties gradually weakens. So the ARCH lattice structure with fewer layers (less than five layers) should be selected as the impact energy absorbing materials at lower impact rate, while at higher impact rate, the number of layers can be selected according to the actual requirements of components or devices space size.

This study shows that Arch lattice structure has excellent energy absorption performance, and provides a theoretical reference for the application of ARCH lattice structure in energy-absorbing materials. ARCH lattice structure is expected to be applied to a variety of energy absorption and anti-impact components or devices, such as aircraft black box fall buffer components, impact resistant layer of bulletproof and landing buffer device.

The purpose of this study is to examine how renewable energy consumption moderates the relationship between inequality and carbon dioxide (CO₂) emissions for Brazil, Russia, India, China and South Africa (BRICS). The nexus between energy use and geopolitical tensions has also been explored.

This study has used distinctive data sets from 1990 to 2018 to explore the interconnections on emission, energy use, inequality and geopolitics. To do away with the difficulties related to heterogeneity and cross-sectional dependence (CD), this paper uses recent estimation methods that are robust to panel heterogeneity and CD.

The results of the panel augmented mean group (AMG) estimation and common correlated effects mean group (CCEMG) estimation verify the environmental Kuznets curve. The findings show that a 1% rise in Gini inequality leads to a 0.24% rise in the CO₂ emission (AMG) method and a 0.17% rise in emissions CCEMG (method). As far as the moderating impact of renewable energy upon Gini measure of inequality is concerned, it is −0.10 AMG and CCEMG methods of estimation, respectively. However, the moderating impact of renewable energy on the geopolitical index leads to a mitigating impact on CO₂ emissions, 0.55% decline in AMG method.

This research makes a distinctive contribution by investigating for the first time to the best of the authors’ knowledge the main pillars of sustainable ecological development in the context of the BRICS nations.

Non-technical dimensions such as spatial quality are just as relevant for energy efficiency as technical and economic dimensions in the renovation of dwellings. However, the significance of non-technical dimensions is often neglected in the energy renovation of dwellings. The purpose of this paper is to demonstrate how the renovation of dwellings for energy efficiency influences spatial quality in the MS-1 building in the neighbourhood of Arlequin, Grenoble, France. The Arlequin case study is part of the ZenN project, nearly zero energy neighbourhoods, funded by the European 7th Framework Programme (Grant Agreement No. 314363).

The impact of the renovation on spatial quality is analysed by crossing technical measures, applied in the energy renovation of dwellings with the definition of spatial quality proposed by Acre and Wyckmans (2014). The spatial quality definition results from a literature review on quality of design and urban life, wherein works of Weber (1995) and Gehl (2010, 2011) are related to the residential use in the scales of the building and block. The impact of renovation on spatial quality is further evaluated by using the spatial quality assessment developed by Acre and Wyckmans (2015). The impact on spatial quality is observed by considering all the renovation measures, instead of only considering the measures primarily related to energy performance. This emphasises the need for a cross-disciplinary approach between technical and non-technical dimensions in the energy renovation of dwellings.

The results display both negative and positive impacts of the energy renovation on spatial quality in the dwellings and emphasise the potential of non-technical dimensions in promoting renovation. The impact on spatial quality is primarily negative when only measures adopted in order to improve energy efficiency are considered in the evaluation.

This paper consists of a novel crossing of technical and non-technical dimensions in energy renovation of dwellings. The work aligns with the current European trend of nurturing energy-deep renovation to reach Europe’s 2050 energy-efficiency targets (Buildings Performance Institute Europe (BPIE) 2011).

Composites 3D printing has the potential to replace the conventional manufacturing processes for engineering applications because it allows for the manufacturing of complex shapes with the possibility of reducing the manufacturing cost. This paper aims to analyse the performance of 3D printed fibre reinforced polymer composites to investigate the energy absorption capabilities and the residual properties before and after impact.

Various composites composed of carbon fibres and Kevlar fibres embedded into both Onyx and nylon matrix were printed using Markforged-Two 3D printers. Specimens with different fibre orientations and fibre volume fractions (Vf) were printed. A drop-weight impact test was performed at energies of 2, 5, 8 and 10 J. Flexural testing was performed to evaluate the flexural strength, flexural modulus and absorbed energy under bending (AEUB) before and after impact. Additionally, 3D printed carbon fibre composites were tested at two different temperatures to study their behaviour under room and sub-ambient temperatures. Failure modes were investigated using optical and high depth of field microscopes for all 3D printed composite samples.

Kevlar/nylon composites with a unidirectional lay-up and 50% Vf exhibited the most prominent results for AEUB at room temperature. The high-Vf carbon fibre composite showed the highest ultimate strength and modulus and performed best at both temperature regimes.

The work, findings and testing produced in this paper are entirely original with the objective to provide further understanding of 3D printed composites and its potential for use in many applications.

The outbreak and the spreading of the COVID-19 pandemic have impacted the global financial sector, including the alternative clean and renewable energy sector. This paper aims to assess the impact of the pandemic, COVID-19 on the stock market indices of the clean energy sector using quantile regression methods.

This study utilized daily data sets on the four major categories of stocks: (1) Morgan Stanley Capital International Global Alternative Energy Index, (2) WilderHill Clean Energy Index, (3) Renewable Energy Industrial Index (RENIXX) and (4) the S&P 500 Global Clean Index. The study adopts a multifactor capital asset pricing model.

Clean and alternative energy stocks are powerful instruments for diversification. However, the impact of the volatility index induced by infectious disease is negative and significant across quantiles.

For investors and policymakers, considering how the uncertainty caused by COVID-19 and the geopolitical index influences renewable energy markets is of great practical importance. For investors, it throws insights into portfolio diversification. For policy makers, it helps to devise strategies to reboot the economy along the lines of the deployment of renewables. This study sheds light on a global green-energy transition and has practical implications for renewable energy resilience in post-pandemic times.

This paper can be considered as a pioneer that explores the nexus between oil prices, interest rates, volatility index, and geopolitical risk upon the stock indices of clean and alternative sources of (renewable) energy in the COVID-19 pandemic situation. The results have important insights into the area of energy and policy decision-making. Additionally, the paper's novelty lies in using the explanatory variables associated with the Covid 19 pandemic.

The aim of this study is to perform a comparative study on sandwich structures with several types of three-dimensional (3D) reticulate cellular structural core designs for their low-energy impact absorption abilities using powder bed additive manufacturing methods. 3D reticulate cellular structures possess promising potentials in various applications with sandwich structure designs. One of the properties critical to the sandwich structures in applications, such as aerospace and automobile components, is the low-energy impact performance.

Sandwich samples of various designs, including re-entrant auxetic, rhombic, hexagonal and octahedral, were designed and fabricated via selective laser sintering (SLS) process using nylon 12 as material. Low-energy drop weight test was performed to evaluate the energy absorption of various designs. Tensile coupons were also produced using the same process to provide baseline material properties. The manufacturing issues such as geometrical accuracy and anisotropy effect as well as their effects on the performance of the structures were discussed.

In general, 3D reticulate cellular structures made by SLS process exhibit significantly different characteristics under low-energy drop weight impact compared to the regular extruded honeycomb sandwich panels. A hexagonal sandwich panel exhibits the largest compliance with the smallest energy absorption ability, and an octahedral sandwich panel exhibits high stiffness as well as good impact protection ability. Through a proper geometrical design, the re-entrant auxetic sandwich panels could achieve a combination of high energy absorption and low response force, making it especially attractive for low-impact protection applications.

There has been little work on the comparative study of the energy absorption of various 3D reticulate cellular structures to date. This work demonstrates the potential of 3D reticulate cellular structures as sandwich cores for different purposes. This work also demonstrates the possibility of controlling the performance of this type of sandwich structures via geometrical and process design of the cellular cores with powder bed additive manufacturing systems.

This research aims to examine the main findings of the SusTEACH study of the carbon-based environmental impacts of 30 higher education (HE) courses in 15 UK institutions, based on an analysis of the likely energy consumption and carbon emissions of a range of face-to-face, distance, online and information and communication technology (ICT)-enhanced blended teaching models.

An environmental assessment of 19 campus-based and 11 distance-based HE courses was conducted using questionnaire surveys to gather data from students and lecturers on course-related travel: the purchase and use of ICTs and paper materials, residential energy consumption and campus site operations. Results were converted into average energy and CO₂ emissions, normalised per student per 100 study hours, and then classified by the primary teaching model used by lecturers.

The main sources of HE course carbon emissions were travel, residential energy consumption and campus site operations. Distance-based HE models (distance, online and ICT-enhanced teaching models) reduced energy consumption by 88 per cent and achieved significant carbon reductions of 83 per cent when compared with campus-based HE models (face-to-face and ICT-enhanced teaching models). The online teaching model achieved the lowest energy consumption and carbon emissions, although there were potential rebound effects associated with increased ICT-related energy consumption and paper used for printing.

New pedagogical designs using online and distance-based teaching methods can achieve carbon reductions by reducing student travel via residential and campus accommodation.

Few studies have examined the environmental performance of HE teaching models. A new classification of HE traditional, online and blended teaching models is used to examine the role of ICTs and the likely carbon impacts.