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The purpose of this paper is to evaluate high strength concrete (HSC) containing polypropylene fibers (PP-fibers) at high temperature under a compressive load.

The use of PP fibers in HSC is known to reduce and at times eliminate the risk of spalling. HSC containing 0, 1 and 2 kg/m³ of PP-fibers were subjected to various temperatures from 20°C to 150°C, 300°C and 450°C and evaluated in a “hot condition”. One group of specimens was in a non-stressed condition during heating (unstressed hot), while a second group was subjected to an initial preload of 40 per cent of the room temperature compressive strength during the heating (stressed hot).

Results showed that stressed concrete containing PP-fibers had lower thermal gradients (the temperature difference between the surface and center temperatures as a function of radial distance) and a decrease in relative porosity. However, the compressive strength of stressed specimens was improved with or without fibers as compared to that of the unstressed HSC. The increased stress levels due to concrete expansion at elevated temperature were also reported. The PP-fibers did not have a significant effect on the compressive strength of stressed concrete as compared to the unstressed state.

This paper reports the compressive strength of PP-fibers in HSC at elevated temperature with and without a pre-load.

While normally the formation of thermally induced residual stresses is seen mainly as detrimental side effect from production processes like welding or casting, the well-directed introduction of thermal residual stresses can also be used as tool to retard fatigue crack growth (FCG). In the presented paper, the use of a defocused laser to modify the residual stress state, and by that to retard the FCG, is examined. The focus lies on the simulation-based optimisation of the heating line position for achieving a maximum fatigue life. The paper aims to discuss these issues.

In the presented work, the developed prediction methodology for the FCG coupling process simulation and subsequent fracture mechanics analysis is used to identify the optimum positioning of either one or two heating lines on a C(T)100 specimen that leads to a maximised total lifetime. Afterwards, the prediction results are validated experimentally for selected cases.

The predictions match the experiments within the experimental scatter indicating the correct identification of the optimum heating line positions. This demonstrates the large potential for reducing the experimental effort needed for design optimisation using the proposed strategy.

The used methodology of coupling of welding simulation with subsequent fracture mechanics analysis in order to optimise the FCG behaviour of structures is innovative and only very few published studies addressed parts of similar approaches.

The purpose of this paper is to study the effect of trailing liquid nitrogen (LN2) heat sink on arc welding of mild steel plates. The effect on temperature field, stress and distortions are studied using experimental and numerical methods.

The methodology consists of experimental and numerical methods. The temperature measured at a point near the arc is used to estimate the cooling capacity of the heat sink using inverse heat transfer (IHT) method. The estimated cooling flux is applied to the finite element model to study the stress and distortions using LN2 heat sink. The stresses are measured using X‐ray diffraction technique and the distortions using dial gauges.

IHT method has been employed in estimating the cooling capacity of the LN2 jet. This has been applied to welding to study the effect on weld induced stresses and distortions. The method can be extended to calculate the heat removal rate in various manufacturing processes where cooling is employed.

The lack of temperature dependent material properties resulted in deviation of stresses between analytical results and experiment values.

IHT method developed for heat removal capacity of trailing heat sink is a contribution. The estimated heat flux shows good agreement in analytical and experimental temperature values. These temperatures have been extended to calculate stresses and out of plane distortions in welding and there is a reasonable agreement between finite element analysis and experimental results.

This paper aims to present the results of a study on the behaviour of a pre-stressed cable steel truss exposed to fire under fire conditions, basing on the results of a large programme of experimental tests.

The research investigated the deformation and stress change on a pre-stressed steel cable, including the deflection and displacements at different joints and fire behaviour of the pre-stressed steel cable. In other words, the structural behaviours at different loaded pre-stress, the vertical loading, steel cable height, truss dimension and the final temperature were compared in case of fire.

The results showed that the strain of longitudinal chord was far larger than those of the transverse chords, the strains of lower chords were significantly larger than those of the upper chords, strain of the chord near the longitudinal centreline were also larger than those of the outside transverse chords. During heating, the displacement and strain gradually changed from linear to nonlinear with loading, and the yielded chord had also in an order those chords which were at mid-span and near to the longitudinal centreline, yielded at first.

Temperatures in the furnace and at several points of the pre-stressed cable steel truss, as well as deformations, deflections and the stress changes of upper chord and the bottom steel cable and the change of displacement at different joint were measured to achieve those goals and, consequently, to assess the deformation behaviours and temperature of the pre-stressed steel cable.

The trapped geothermal heat in the infinite rock mass through which mine tunnels are excavated is a great threat to the safety of personnel and mine operating equipment in deep underground hot mines. In order to lessen the temperature inside the tunnel a considerable amount of energy is being spent by the way of using ventilation and cooling systems to dissipate the heat. However, operational costs of the system rise quite considerably, especially as the mines get deeper. Shotcrete is used both as a structural lining and as an effective insulation to reduce the heat load on the ventilation and cooling system within such tunnels. The paper aims to discuss these issues.

In order to analyse this problem of heat flow and thermal stresses and their time dependent pattern, several cylindrical models, in both analytical and numerical forms, are discussed and compared in this paper.

This study shows the validation of ABAQUS® software to predict the time dependent temperature and the thermal stresses in mine tunnels through the comparisons with the available analytical models. Further, thermal insulation effects of shotcrete are also evaluated with these theoretical models and it is found that all the models gave results in close agreements with one another.

Therefore, this study provides the theoretical proof for advantages in applying shotcrete as the thermal insulation layer in underground mines.

During the powder bed fusion process, thermal distortion is one big problem owing to the thermal stress caused by the high cooling rate and temperature gradient. For the purpose of avoiding distortion caused by internal residual stresses, support structures are used in most selective laser melting (SLM) process especially for cantilever beams because they can assist the heat dissipation. Support structures can also help to hold the work piece in its place and reduce volume of the printing materials. The mitigation of high thermal gradients during the manufacturing process helps to reduce thermal distortion and thus alleviate cracking, curling, delamination and shrinkage. Therefore, this paper aims to study the displacement and residual stress evolution of SLMed parts.

The objective of this study was to examine and compare the distortion and residual stress properties of two cantilever structures, using both numerical and experimental methods. The part-scale finite element analysis modeling technique was applied to numerically analyze the overhang distortions, using the layer-by-layer model for predicting a part scale model. The validation experiments of these two samples were built in a SLM platform. Then average displacement of the four tip corners and residual stress on top surface of cantilever beams were tested to validate the model.

The validation experiments results of average displacement of the four tip corners and residual stress on top surface of cantilever beams were tested to validate the model. It was found that they matched well with each other. From displacement and residual stress standpoint, by introducing two different support structure, two samples with the same cantilever beam can be successfully printed. In terms of reducing wasted support materials, print time and high surface quality, sample with less support will need less post-processing and waste energy.

Numerical modeling in this work can be a very useful tool to parametrically study the feasibility of support structures of SLM parts in terms of residual stresses and deformations. It has the capability for fast prediction in the SLMed parts.

Agricultural workers represent an important part of the population exposed to high heat-related health and productivity risks. This study aims to estimate the heat-related productivity loss (PL) for moderate work activities in sun and shady areas and evaluating the economic cost locally in an Italian farm and generally in the whole province of Florence. Benefits deriving by working in the shade or work-time shifting were provided. Comparisons between PL estimated in Mediterranean (Florence, Italy) and subtropical (Guangzhou, China) areas were also carried out.

Meteorological data were collected during summers 2017–2018 through a station installed in a farm in the province of Florence and by two World Meteorological Organization (WMO)‐certified meteorological stations located at the Florence and Guangzhou airports. These data were used to calculate the wet-bulb globe temperature and to estimate the hourly PL and the economic cost during the typical working time (from 8 a.m. to 5 p.m.) and by advancing of 1 h and 2 h the working time. Significant differences were calculated through nonparametric tests.

The hourly PL and the related economic cost significantly decreased (p < 0.05) by working in the shade and by work-time shifting. Higher PL values were observed in Guangzhou than in Florence. The decrease of PL observed by work-time shifting was greater in Florence than in Guangzhou.

Useful information to plan suitable heat-related prevention strategies to counteract the effects of heat in the workplace are provided. These findings are essential to quantify the beneficial effects due to the implementation of specific heat-related adaptation measures to counter the impending effects of climate change.

Studies of worker heat stress and strain in various countries have found that heat exposure is often likely to exceed the upper threshold limit of international standards. Heat strain data such as oral temperature, recovery heart rate, average heart rate and other work‐related information were investigated to study the impact of strenuous tasks in a hot climate. The study attempted to establish relationships between exposure to heat and heat strain data which could be used as the basis of ergonomic intervention and low‐cost solutions to the avoidance or mitigation of occupational risks.

In the past many scientists have published papers on hormesis, on molecular stress responses, and on the similia principle in homoeopathy. Very few, however, have stressed a common base of interdependence of these fields. Reviews the most important of these studies to demonstrate their evolution and their mutual importance. Furthermore, a multidisciplinary approach is chosen to demonstrate research into the beneficial effects of subharmful doses of toxicants administered in suboptimal conditions (such as in stressed or injured organisms and cells).

Enhancing the resilience of cities and strengthening risk-informed decision-making are defined as key within the Global Agenda 2030. Implementing risk-informed decision-making also requires the consideration of scenarios of exposure and vulnerability. Therefore, the paper presents selected scenario approaches and illustrates how such vulnerability scenarios can look like for specific indicators and how they can inform decision-making, particularly in the context of urban planning.

The research study uses the example of heat stress in Ludwigsburg, Germany, and adopts participatory and quantitative forecasting methods to develop scenarios for human vulnerability and exposure to heat stress.

The paper indicates that considering changes in future vulnerability of people is important to provide an appropriate information base for enhancing urban resilience through risk-informed urban planning. This can help cities to define priority areas for future urban development and to consider the socio-economic and demographic composition in their strategies.

The value of the research study lies in implementing new qualitative and quantitative scenario approaches for human exposure and vulnerability to strengthen risk-informed decision-making.