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The large blood vessels (LBV) would act as a heat sink and hence play a significant role during photo-thermal therapy. Gold nanoshell was considered as a high-heat absorbing agent in photo-thermal heating to reduce the cooling effect of LBV. The heat sink effect of LBV results in insignificant irreversible tissue thermal damage. The paper aims to discuss these issues.

In this paper, the thermal history of tissue embedded with LBV during photo-thermal heating were calculated using finite element-based simulation technique. A volumetric laser source term based on modified Beer-Lambert law was introduced to model laser heating. The numerically predicted temperature drop was validated against that of previously performed experiments by the authors on tissue mimic embedded with simulated blood vessels. In the later part of the study, Arrhenius equation was coupled with the energy equation to investigate and report the irreversible thermal damage to the bio-tissues.

The results obtained conclude that tissue with different orientation of blood vessels results in different thermal response at the tissue surface. Gold nanoshells were introduced into the laser irradiated tissue to overcome the cooling effect of LBV during plasmonic photo-thermal heating. The effect of size and concentration of nanoparticles on tissue heating were analyzed. The predicted damage parameter was much lower in case of tissue embedded with blood vessel than that predicted in case of bare tissue, which results in incomplete tissue necrosis. Finally, the effects of laser specification, blood vessel specification and blood perfusion on the tissue thermal damage were examined.

The conjugate energy equations in conjunction with Arrhenius equation were solved numerically to predict the tissue irreversible damage embedded with LBV.

The main aim of this research was to investigate the effectiveness of various strengthening techniques in restoring the structural performance of reinforced concrete (RC) beams damaged by elevated temperatures.

Three different strengthening techniques, namely, high-strength fibre reinforced concrete (HSFRC), ferrocement (FC) jacketing and externally bonded fibre-reinforced polymer (FRP) were used. Series of RC beams were casted, heated, strengthened and tested to investigate the influence of various variables. The variables of the study were type of strengthening and level of heat damage.

Externally bonded FRP was found to be the best among the various techniques, especially with respect to strength and stiffness restoration. On the contrary, the FRP strengthening was not that effective in restoring the energy absorption capacity of beams compared to HSFRC and FC techniques of strengthening. The chosen strengthening techniques were able to restore the failure mode of beams to flexural failure, which was found to have changed to shear failure in case of heated unstrenghthened beams.

This research program has contributed to the fundamental understanding of designing post fire retrofit solutions for RC beams.

This paper aims to study the residual test results under uni-axial compression of tie confined pre-damaged normal strength concrete short columns subjected to elevated temperatures.

The test variables included temperature of exposure, spacing of transverse confining reinforcement and pre-damage level. An experimental program was designed and carried out involving testing of hoop confined concrete cylindrical specimens exposed to elevated temperatures ranging from room temperature to 900 °C.

The test results indicate that the residual strength, strain corresponding to the peak stress and the post-peak strains of confined concrete are not affected significantly up to an exposure temperature of 300 °C. However, the peak confined stress falls and the corresponding strain increase considerably in the temperature range of 600 to 900 °C. It is shown that an increase in the degree of confinement reinforcement results in an increased residual strength and deformability of pre-damaged confined concrete.

It is applicable in finding the residual strength and strain of the pre-damaged confined concrete in uni-axial compression after exposure to elevated temperature.

The practical implications is that the test result is applicable in finding the residual strengths of pre-damaged confined concrete under uni-axial compression after exposure to elevated temperature.

The main aim of the present investigation is to provide experimental data on the residual behaviour of pre-damaged confined concrete subjected to high temperatures.

The results of this study may be useful for developing the guidelines for designing the confinement reinforcement of reinforced concrete columns against the combined actions of earthquake and fire, as well as for designing the retrofitting schemes after these sequential disasters.

This study aims to conduct an experimental study and finite element model (FEM) to investigate the flexural behavior of heat-damaged beams strengthened/repaired by hybrid fiber-reinforced polymers (HFRP).

Two groups of beams of (150 × 250 × 1,200) mm were cast, strengthened and repaired using different configurations of HFRP and tested under four-point loadings. The first group was kept at room temperature, while the second group was exposed to a temperature of 400°C.

It was found that using multiple layers of carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP) enhanced the strength more than a single layer. Also, the order of two layers of FRP showed no effect on flexural behavior of beams. Using a three-layer scheme (attaching the GFRP first and followed by two layers of CFRP) exhibited increase in ultimate load more than the scheme attached by CFRP first. Furthermore, the scheme HGC (heated beam repaired with glass and carbon, in sequence) allowed to achieve residual flexural capacity of specimen exposed to 400°C. Typical flexural failure was observed in control and heat-damaged beams, whereas the strengthened/repaired beams failed by cover separation and FRP debonding, however, specimen repaired with two layers of GFRP failed by FRP rupture. The FEM results showed good agreement with experimental results.

Few researchers have studied the effects of HFRP on strengthening and repair of heated, damaged reinforced concrete (RC) beams. This paper investigates, both experimentally and analytically, the performance of externally strengthened and repaired RC beams, in flexure, with different FRP configurations of CFRP and GFRP.

Earthquake tremors not only increase the chances of fire ignition but also hinder the fire-fighting efforts due to the damage to the lifelines of a city. Most of the international codes have independent recommendations for structural safety against earthquake and fire. However, the possibility of a multi-hazard event, such as fire following an earthquake is seldom addressed.

This paper presents an experimental study of Reinforced Concrete (RC) columns in post-earthquake fire (PEF) conditions. An experimental approach is proposed that allows the testing of a column instead of a full structural frame. This approach allows us to control the loading and boundary conditions individually and facilitates the testing under a variety of these conditions. Also, it allows the structure to be tested until failure. The role of parameters, such as earthquake intensity, axial load ratio and the ductile detailing of the column on the earthquake damage and subsequently the fire performance of the structure, is studied in this research. Six RC column specimens are tested under a sequence of quasi-static earthquake loading, followed by combined fire and axial compression loading conditions.

The experiment results indicate that ductile detailed columns subjected to 4% or less lateral drift did not lose significant load-carrying capacity in fire conditions. A lateral drift of 6% caused significant damage to the columns and reduced the load-carrying capacity in fire conditions. The level of the axial load acting on the column at the time of earthquake loading was found to have a very significant effect on the extent of damage and reduction in column load capacity in fire conditions. The columns that were not detailed for a ductile behavior observed a more significant reduction in axial load carrying capacity in fire conditions.

This study is limited to columns of 230 mm size due to the limitations of the test setup. The applicability of these findings to larger column sections needs to be verified by developing a numerical analysis methodology and simulating other post-earthquake-fire tests available in the literature.

The experimental procedure proposed in this paper offers an alternative to the testing of a complete structural frame system for PEF behavior. In addition to the ease of conducting the tests, the procedure also allows much better control over the heating, structural loading and boundary conditions.

The purpose of this paper is to examine the effect of various polypropylene fibre additions (types and volume) to concrete with regard to explosive spalling when subject to high temperatures similar to those experienced in building or tunnel fires.

Medium strength concrete was manufactured with varying proportions of polypropylene fibres. Plain control samples were used to determine the original concrete strength and this was used as a benchmark following high temperature heat tests to evaluate the surface condition and final compressive strength. A pilot study was used to determine an appropriate heat source for the test. This was three Bunsen burners, however sufficient heat could not be generated within 150 mm concrete cubes and the concrete was shown to be a significant insulator and fire protection for structural members. The concrete test cubes were tested in a saturated condition which may reflect conditions where concrete is used in an external environment and thus is subject to soaking.

One hundred and fifty millimetre concrete cubes with and without fibres were placed into a furnace at 1,000°C. Explosive spalling was shown to be reduced with the use of polypropylene fibres but the final compressive strength of concrete was significantly reduced and had little residual structural value after a two hour period of heating.

As the concrete tested was saturated, this condition provided a worst case scenario with regards to the build up of hydrostatic and vapour pressure within the cube. A range of percentage moisture contents would produce a more evenly balanced view of the effects of fibres in concrete. A single grade of concrete was used for the test. As the permeability of concrete influences the rate at which steam can escape from the interior of a saturated concrete cube, testing a range of concrete strengths would show this aspect of material performance with regard to spalling and final residual strength. Further research is recommended with regard to moisture contents, strengths of concrete and a range of temperatures.

This research has significance for the designer, in that buildings subject to terrorist activity may suffer from impact damage and an outbreak of fire following the initial attack.

The use of polypropylene fibres in concrete to provide anti spalling qualities is relatively new and this research adds to the knowledge regarding fibre type and volume with regard to first spall time, total area and number of areas subject to spalling and the final compressive strength of concrete following two hours of raised temperatures.

A Boeing 776–200ER took off from Heathrow for a direct flight to New York and during the take‐off, smoke was seen by a ground observer to be coming from the left engine. This smoke was described as similar in appearance to that emitted by “old technology” engines such as those installed in Boeing 707 aircraft and was seen to persist until the aircraft entered cloud. As the aircraft was passing FL180 in the climb, the left engine fire warning system operated twice for very short periods. All engine instrument indications were normal but the commander detailed a member of the cabin staff to make a visual inspection of the left engine from the main cabin. As the aircraft was approaching FL210 and before the commander had received a report from the cabin attendant, the left engine fire warning system operated once more and this time persisted.

The purpose of this paper is to explore the reasons behind the occurrence of serious accidents during interior firefighting operations of the German fire services despite numerous and significant safety improvements.

The paper is a case study relying on accident investigation reports from four accidents that happened in Germany between 2005 and 2016.

The study finds that the system of interior attack firefighting in Germany is a tightly coupled and complex system, as described by the normal accident theory, and that all four cases were caused by unanticipated interactions between components of the system and were therefore system accidents as described by the normal accident theory. This means that these accidents were ultimately caused by the properties of the system that make it susceptible to system accidents.

To prevent these accidents, there is a need to change the properties of the system that make it susceptible to system accidents.

The study identifies factors that make the system inherently dangerous. Hence, practical measures can be undertaken to counter these factors and make the system safer.

This study is the first application of the normal accident theory to the operations of the fire services in general, and it is the first theory-guided inquiry into accidents of the German fire services. The findings of this paper provide new explanations for accidents and new approaches to improve safety during interior attack firefighting operations.

The purpose of this paper is to study the damage induced in “green” and synthetic composites under impact loading.

The study was focussed on epoxy-based composites reinforced with woven hemp or glass fibres. Six assessment techniques were employed in order to analyse and compare impact damages: eye observation, back face relief, terahertz spectroscopy, laser vibrometry, x-ray micro-tomography and microscopic observations.

Different damage detection thresholds for each material and technique were obtained. Damage induced by mechanical and laser impacts showed relevant differences, but the damage mechanisms are similar in both types of impact: matrix cracks, fibre failure, debonding at the fibres/matrix interface and delamination. Damage shape on back surfaces is similar after mechanical or laser impacts, but differences were detected inside samples.

The combination of these six diagnoses provides complementary information on the damage induced by mechanical or laser impacts in the studied green and synthetic composites.

This study aims to provide a factual justification of the extension to fire conditions of the well-known design models for the calculations of R/C members at the ultimate limit state in shear and torsion. Both solid and thin-walled sections are considered. In the latter case, the little-known topic of shear-transfer mechanisms at high temperature is introduced and discussed.

Both the effective-section method and the zone method are treated, as well as the strut-and-tie models required by the analysis of the so-called D zones (discontinuity zones), where heat-enhanced cracking further bears out the phenomenological basis of the models.

The increasing role played by the stirrups in shear and by the rather cold concrete core in torsion stand out clearly in fire, while high temperatures rapidly reduce the contributions of such resisting mechanisms as concrete-teeth bending, aggregate interlock and dowel action.

On the whole, beside quantifying the side contributions of web mechanisms and section core in fire conditions, this study indicates a possible approach to extend to fire the available models on the coupling of shear and bending, and shear and torsion in R/C members.