Application of Foamed Concrete and Cold-Formed Steel Decking as Lightweight Composite Slabs: Experimental Study On Structural Behaviour

Foamed concrete composite slabs (FCCS) are currently enjoying great popularity in the construction industry. Unlike conventional composite slabs, FCCS has an advantage in solving the selfweight penalty. With the advanced research in concrete technology, foamed concrete with sufficient strength properties  to meet the requirements of standard code of practise has been successfully introduced. Foamed concrete is known for its lightweight and versatility. This paper presents an experimental study on ultimate load, maximum deflection and failure mode of FCCS. Of interest are the effects of dry density and slab thickness. The slab specimens with a span of 1800 mm, a width of 840 mm and different thicknesses from 100 mm to 150 mm were prepared for the three-point bending test. The dry density of foamed concrete is 1400 kg/m3, 1600 kg/m3, and 1800 kg/m3, which has a compressive strength of about 20 MPa to 40 MPa. Dry density and slab thickness have been observed to have significant effects on ultimate load and maximum deflection. Higher dry density of foamed concrete provides better slip resistance and thus reduces shear bond failure. On the other hand, slab specimens with a higher slab thickness tend to have better bearing capacity due to greater bending stiffness. The main failure mode is dominated by localised bending on the profiled steel deck, slip-displacement and fracture of the foamed concrete

Application of Foamed Concrete and Cold-Formed Steel Decking as Lightweight Composite Slabs: Experimental Study On Structural Behaviour

Foamed concrete composite slabs (FCCS) are currently enjoying great popularity in the construction industry. Unlike conventional composite slabs, FCCS has an advantage in solving the selfweight penalty. With the advanced research in concrete technology, foamed concrete with sufficient strength properties  to meet the requirements of standard code of practise has been successfully introduced. Foamed concrete is known for its lightweight and versatility. This paper presents an experimental study on ultimate load, maximum deflection and failure mode of FCCS. Of interest are the effects of dry density and slab thickness. The slab specimens with a span of 1800 mm, a width of 840 mm and different thicknesses from 100 mm to 150 mm were prepared for the three-point bending test. The dry density of foamed concrete is 1400 kg/m3, 1600 kg/m3, and 1800 kg/m3, which has a compressive strength of about 20 MPa to 40 MPa. Dry density and slab thickness have been observed to have significant effects on ultimate load and maximum deflection. Higher dry density of foamed concrete provides better slip resistance and thus reduces shear bond failure. On the other hand, slab specimens with a higher slab thickness tend to have better bearing capacity due to greater bending stiffness. The main failure mode is dominated by localised bending on the profiled steel deck, slip-displacement and fracture of the foamed concrete

Natural Frequency of Lightweight Composite Slabs Based On Experimental Study and Numerical Modelling

Recently, lightweight composite slabs have become increasingly popular. Lightweight composite slabs are an innovation that provides a better and more convenient construction method for floor systems. Under dynamic loads, lightweight composite slabs may experience meagre inertia forces due to poor stiffness or low mass. Compared to conventional composite slabs, lightweight composite slabs are 40% lighter and more susceptible to structural resonance. Therefore, the vibration behaviour must be controlled to avoid discomfort issues. This study investigates the natural frequency of lightweight composite slabs through experimental study and numerical modelling. In the experimental study, lightweight composite slabs were prepared for the hammer-impact test. The slab thickness ranges from 100 mm to 200 mm. In numerical modelling, lightweight composite slabs were modelled in SAP2000 using a unique technique called the simplified equivalent plate model. The effective material properties were derived from the rule of mixtures and depend exclusively on elastic properties with strength characteristics. The results of the experimental study and numerical modelling agree positively. The natural frequency decreased with slab thickness, signifying that the natural frequency is dominated by mass rather than stiffness. Overall, the natural frequency of lightweight composite slabs is around 27.23Hz to 31.45Hz

Natural Frequency of Lightweight Composite Slabs Based On Experimental Study and Numerical Modelling

Recently, lightweight composite slabs have become increasingly popular. Lightweight composite slabs are an innovation that provides a better and more convenient construction method for floor systems. Under dynamic loads, lightweight composite slabs may experience meagre inertia forces due to poor stiffness or low mass. Compared to conventional composite slabs, lightweight composite slabs are 40% lighter and more susceptible to structural resonance. Therefore, the vibration behaviour must be controlled to avoid discomfort issues. This study investigates the natural frequency of lightweight composite slabs through experimental study and numerical modelling. In the experimental study, lightweight composite slabs were prepared for the hammer-impact test. The slab thickness ranges from 100 mm to 200 mm. In numerical modelling, lightweight composite slabs were modelled in SAP2000 using a unique technique called the simplified equivalent plate model. The effective material properties were derived from the rule of mixtures and depend exclusively on elastic properties with strength characteristics. The results of the experimental study and numerical modelling agree positively. The natural frequency decreased with slab thickness, signifying that the natural frequency is dominated by mass rather than stiffness. Overall, the natural frequency of lightweight composite slabs is around 27.23Hz to 31.45Hz

Accidents preventive practice for high-rise construction

The demand of high-rise projects continues to grow due to the reducing of usable land area in Klang Valley, Malaysia.The rapidly development of high-rise projects has leaded to the rise of fatalities and accidents.An accident that happened in a construction site can cause serious physical injury.The accidents such as people falling from height and struck by falling object were the most frequent accidents happened in Malaysian construction industry.The continuous growth of high-rise buildings indicates that there is a need of an effective safety and health management. Hence, this research aims to identify the causes of accidents and the ways to prevent accidents that occur at high-rise building construction site.Qualitative method was employed in this research. Interview surveying with safety officers who are involved in highrise building project in Kuala Lumpur were conducted in this research. Accidents were caused by man-made factors, environment factors or machinery factors.The accidents prevention methods were provide sufficient Personal Protective Equipment (PPE), have a good housekeeping, execute safety inspection, provide safety training and execute accidents investigation.In the meanwhile, interviewees have suggested the new prevention methods that were develop a proper site layout planning and de-merit and merit system among subcontractors, suppliers and even employees regarding safety at workplace matters.This research helps in explaining the causes of accidents and identifying area where prevention action should be implemented, so that workers and top management will increase awareness in preventing site accidents

A prophylactic vaccine for breast cancer?

Cancer vaccines are the Holy Grail for patients and clinicians alike. The possibility that we can be vaccinated against common cancers is very appealing and the socioeconomic consequences are significant. A recent paper from Vincent Tuohy's group, published in the journal Nature Medicine, suggests a new approach for the development of a prophylactic vaccine for breast cancer. Their strategy was to induce mammary gland failure in mice by immunisation with an antibody specific to a milk protein that resulted in autoimmunity during lactation. This also showed some efficacy as a therapeutic vaccine. Can we look forward to the elimination of breast cancer

"The End of Immortality!" Eternal Life and the Makropulos Debate

Responding to a well-known essay by Bernard Williams, philosophers (and a few theologians) have engaged in what I call “the Makropulos debate,” a debate over whether immortality—“living forever”—would be desirable for beings like us. Lacking a firm conceptual grounding in the religious contexts from which terms such as “immortality” and “eternal life” gain much of their sense, the debate has consisted chiefly in a battle of speculative fantasies. Having presented my four main reasons for this assessment, I examine an alternative and neglected conception, the idea of eternal life as a present possession, derived in large part from Johannine Christianity. Without claiming to argue for the truth of this conception, I present its investigation as exemplifying a conceptually fruitful direction of inquiry into immortality or eternal life, one which takes seriously the religious and ethical surroundings of these concepts

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival