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How big should ventilation openings be in ventilated attics? In Denmark, guidelines describe what is sufficient to remove excess moisture penetrating through the ceiling. These guidelines are based on many years of experience. An important parameter is the tightness of the ceiling. With current regulations for the airtightness of buildings, convection through the ceiling is reduced compared to older buildings. Therefore, it is relevant to review these old rules of thumb and maybe revise them. In this two-year study, tests with different sizes of ventilation openings were conducted in a test house with 18 separate ventilated attics and airtight ceilings. One third of the attics were ventilated according to the guidelines, one third’s ventilation was reduced by one third and the last third had 50 % ventilation of the recommendations. Hourly measurements of temperature and relative humidity in the attics were conducted. Rafters in the attics were tested for mould growth. Six different types of insulation systems were used in the attics (with and without a vapour barrier, different insulation materials, and insulation thickness), therefore, the study also includes these differences. Earlier investigations, with full ventilation in all attics, showed no significant hygrothermal differences between them; consequently, it was assumed that the amount of ventilation would be decisive for the hygrothermal performance. This study follows up on this assumption. Results show little differences between the attics, mainly that having a vapour barrier becomes more important with reduced ventilation, and the insulation thickness and thereby U-value is of less importance. Reducing the requirements for ventilation of attics could be relevant, provided that the ceiling is airtight.

Over the recent years, innumerable upheaval has been done in the field of steel construction industry, out of which pre-Engineered buildings (PEB) are one of the most remarkable ones. Pre-Engineered buildings are typical steel structures which are pre-fabricated and the designs are pre-determined which are contemplated to be more cost efficient, because of the tapered sections being utilized, in accordance with its bending moment requirement. These types of structures will not only be cost effective and environmentally friendly but also more flexible, thus eradicating the failure due to sequel of seismic forces. PEBs are generally industrial structures, which are designed for enormous spans. In this research work, the variation of structural behaviour of PEBs when it’s been embraced with considerably increased spans (30 m, 60 m and 90m) are compared and studied. In general, hot rolled tapered I-sections are used in erection of a PEB. Due to the inadequacy in connection configurations available, Pre- Engineered light weight cold form steel structures with tubular steel sectional connections are not well renowned. An attempt is also been made to bring out tubular sectional connections for the beam- rafter junction in all the PEBs deigned for 30 m, 60 m and 90m using E350 steel. Typical connections are proposed for both main frames and the gable frames of the PEB. The outcome of this study appears to be contended for at both the junctions in 30 m span and 60 m span, but 90 m main joint fails, due to the substantial bending moments developed across the major axis. So, these set of connections can be adopted for PEBs up to a moderate span, which helps in reducing the weight of steel that is been utilized in the construction, which successively foster sustainability.

Radiocarbon (14C) dating of sediment deposition around Antarctica is often challenging due to heterogeneity in sources and ages of organic carbon in the sediment. Chemical and thermochemical techniques have been used to separate organic carbon when microfossils are not present. These techniques generally improve on bulk sediment dates, but they necessitate assumptions about the age spectra of specific molecules or compound classes and about the chemical heterogeneity of thermochemical separations. To address this, the Rafter Radiocarbon Laboratory has established parallel ramped pyrolysis oxidation (RPO) and ramped pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) systems to thermochemically separate distinct carbon fractions, diagnose the chemical composition of each fraction, and target suitable RPO fractions for radiocarbon dating. Three case studies of sediment taken from locations around Antarctica are presented to demonstrate the implementation of combined RPO-AMS and Py-GC-MS to provide more robust age determination in detrital sediment stratigraphy. These three depositional environments are good examples of analytical and interpretive challenges related to oceanographic conditions, carbon sources, and other factors. Using parallel RPO-AMS and Py-GC-MS analyses, we reduce the number of radiocarbon measurements required, minimize run times, provide context for unexpected 14C ages, and better support interpretations of radiocarbon measurements in the context of environmental reconstruction.

Direct atmospheric 14CO2 measurements began in New Zealand in 1954, initially to improve 14C as a dating tool, but quickly evolving into a method for understanding the carbon cycle. These early 14CO2 measurements immediately demonstrated the existence of an “Atom Bomb Effect,” as well as an “Industrial Effect.” These two gigantic tracer experiments have been utilized via 14CO2 measurements over the years to produce a wealth of knowledge in multiple research fields including atmospheric carbon cycle research, oceanography, soil science, and aging of post-bomb materials.

Atovaquone-Proguanil is considered causal prophylaxis (inhibition of liver-stage schizonts) for Plasmodium falciparum, however, its causal prophylactic efficacy for P. vivax is not known. Travelers returning to non-endemic areas, provide a unique opportunity to study P. vivax prophylaxis. A retrospective observational study. For 11 years Israeli rafters who had traveled to the Omo River in Ethiopia, a highly malaria endemic area, were followed for at least one year after their return. Malaria prophylaxis used during this period included: mefloquine, doxycycline, primaquine and atovaquone-proguanil. Prophylaxis failure was divided into early (within a month of exposure) and late malaria. 252 travelers were included.in the study. 62 (24.6%) travelers developed malaria, 56 (91.9%) caused by P. vivax, with 54 (87.1%) cases considered as late malaria. Among travelers using atovaquone-proguanil there were no cases of early P.falciparum or P. vivax malaria. However, 50.0% of atovaquone-proguanil users developed late vivax malaria, as did 46.5% and 43.5% of mefloquine and doxycycline users; respectively; only 2 (1.4%) primaquine users developed late malaria (p<0.0001). Short-course atovaquone-proguanil appears to provide causal (liver-schizont stage) prophylaxis for P. vivax, but is ineffective against late, hypnozoite-reactivation-related attacks. These findings suggest that primaquine should be considered as the chemoprophylactic agent of choice for areas with high co-circulation of P. falciparum and P. vivax.

We consider the coatings of single-story industrial buildings of frame type, which in a typical solution are made in the form of a flooring of ribbed plates on rafters, trusses or arches. There is a high complexity of manufacturing, transportation and installation of structures and a large height of the coating. We offer truss beams-slabs of box-shaped cross-section, the height of which varies stepwise along the length, being limited by a square parabola at the top. Beams are installed on the substructure structures in a row, and between them on a permanent formwork of wooden boards are arranged monolithic sections of the plate. The calculation of deformations is performed taking into account the inelastic deformation of concrete and rebar in accordance with the recommended norms of state diagrams: three-line for concrete and two-line for rebar. The results of the calculation of a beam-plate with a span of 30 m, which has 5 different stages, the height of which is selected so that the required cross-section of the reinforcement remains constant along the entire length of the structure.

It is known that in prehistoric Hokkaido, the wood of the Japanese lilac ( Syringa reticulata ) was used as structural material; for example, in pillars and rafters of dwellings. This suggests that Japanese lilac wood has useful properties, such as high strength and strong decay resistance. However, few studies have been conducted on the wood strength and decay resistance of this species. The present study was undertaken to evaluate the strength and decay resistance of Japanese lilac wood and reveal the factors responsible for its general use in prehistoric periods. The results of mechanical tests show that the strength of the wood, as quantified through several different indices, is above moderate. In particular, static modulus of elasticity and modulus of rupture of Japanese lilac wood were higher than those of other species commonly found in Hokkaido. Regarding decay resistance, the mass-loss rate was only 1.6% after incubation with Trametes versicolor for 60 days. We conclude that Japanese lilac is a suitable material for structural materials in which high bending strength is desired. In addition, its extremely high decay resistance makes it conducive to long-term use outdoors. Overall, the results of this study indicate that the extremely high decay resistance and excellent bending strength of Japanese lilac were the main reasons for its use in prehistoric periods.

Economic impact studies in adventure tourism help to communicate and quantify the positive effects of activities, projects, and events on a local community. Some of these positive effects include an increase in employment, wages, local tax revenue, and revenue for different local industries. Economic impact studies have measured the impacts of tourists when participating in events or outdoor leisure activities, but few prior studies have measured the economic impact of outdoor adventure sports travel. To fill this research gap, the authors conducted an economic impact study of adventure sports participants (whitewater rafters) to the Ocoee River region in Ocoee, TN.

The existing early-warning methods primarily rely on detecting structural displacements which are often challenging to measure accurately in real fire scenarios. To develop innovative early-warning strategies, this paper experimentally and numerically investigates the fire-induced collapse of an 8 m × 6 m steel portal frame assembly. Detailed thermo-structural responses of the frame were measured and presented, including the displacements and rotations. The results revealed that the vertical mid-span displacement and horizontal displacement at the rafter end are key to developing an effective early-warning system. Structural rotations seem sensitive to structural deformation and emerges as a valuable safety indicator for structural systems. Furthermore, parametric analyses were carried out in order to investigate the effect of load ratio, fire protection and heating curve on key parameters of the structure subjected to fires. It is discovered that the increased load ratio can reduce the peak value of vertical displacement at the mid-span of the rafter. A rotational angle of 6° in the steel beams is optimal for predicting the collapse of steel portal frames in fire conditions. Based on the parametric studies, an innovative early-warning approach using rotational angles is proposed and validated against the test frame, demonstrating significant applicability and reliability. The rotation-based early-warning approach works in two distinct stages, being activated respectively by the maximum and zero rotational angles at the end of rafter. The early-time ratios for the respective warning stages are 0.65 and 0.88. For better precision and practical reliability, it is further recommended to combine the rotation-based and displacement-based approaches for the on-site early-warning of fire-induced collapse of portal frames.

The main aim of this study is to assess the performance and residual strength of post-fire non-prismatic reinforced concrete beams (NPRC) with and without openings. To do this, nine beams were cast and divided into three major groupings. These groups were classified based on the degrees of heating exposure temperature chosen (ambient, 400, and 700°C), with each group containing three non-prismatic beams (solid, 8 trapezoidal openings, and 8 circular openings). Experimentally, given the same beam geometry, increasing burning temperature caused degradation in NPRC beams, which was reflected in increased mid-span deflection throughout the fire exposure period and also residual deflection after cooling. But on the other hand, the issue with existing openings was exacerbated. The burned NPRC beams were then gradually cooled down by leaving them at ambient temperature in the laboratory, and the beams were loaded until failure to examine the effect of burning temperature degree on the residual ultimate load-carrying capacity of each beam by comparing them to unburned reference beams. It was found, increasing the exposure temperature leads to a reduction in ultimate strength about (5.7 and 10.84%) for solid NPRC beams exposed to 400 and 700°C, respectively related to unburned one, (21.13 -32.8) % for NPRC beams with eight trapezoidal openings, and (10.5 - 12.8) % for those having 8 circular openings. At higher loading stage the longitudinal compressive strain of Group ambient in mid-span of solid beams reach 2700 με, while the others with openings exhibit divergent strain higher than that, it’s about 3300 με meanwhile, the lower chord main reinforcements have been pass beyond yielding stress. Exposure to high temperatures reduces rafters’ stiffness causing a reduction in load carrying capacity, companion with premature failure consequently reduce the strain at the ultimate stage.