We present a microwave realization of finite tight-binding graphene-like structures. The structures are realized using disks with a high index of refraction. The disks are placed on a metallic surface while a second surface is adjusted atop the discs, such that the waves coupling the disks in the air are evanescent, leading to the tight-binding behavior. In reflection measurements the Dirac point and a linear increase close to the Dirac point is observed, if the measurement is performed inside the sample. Resonances due to edge states are found close to the Dirac point if the measurements are performed at the zigzag-edge or at the corner in case of a broken benzene ring.
This article presents data on the deflection of the flat slabs in the Cardington in-situ concrete building. The effects of concrete tensile strength and reinforcement on long-term deflection are discussed. A coefficient K is proposed to compare cracking induced at striking, construction of subsequent slabs and service loading. Deflections of the Cardington slabs are shown to be almost linearly related to the minimum value of K. An effective concrete strength is proposed for use in deflection calculations to account for the effect of construction loading.
This paper presents a novel incremental procedure for the prediction of slab deflection due to a time-varying load. The procedure extends the moment curvature method given in CEB-FIP Model Code for Concrete Structures 1990 (MC90). The procedure has been incorporated into a finite-element program which has been used to predict long-term slab deflections in the Cardington in-situ concrete building. It is shown that long-term deflections in the Cardington slabs are underestimated significantly if the effect of construction loading is neglected. A simplified method is proposed for calculating deflection which takes construction loading into account.
Waste generation and its management are being widely debated across the globe and in recent years, it has become a niche spot. Both the developed and developing countries are trying to find out new ways for climate change mitigation and adoption options respectively. Global climate change is a burning issue and presently Bangladesh is facing grave situations. A large proportion of the waste is not properly managed and dumped in unplanned sites that are creating severe environmental hazards. Gradually, it can be replicated in each urban and rural centre and growth points of Bangladesh can play a vital role in climate change mitigation. Implementation of the 3Rs will have a profound socioeconomic impact, also modern 3Rs (Reduce, Reuse and Recycle) strategy acts as a sustainable and socioeconomic option for climate change mitigation by reducing green house gas (GHG) emission from the municipal solid waste.
Traditionally, handmade gold jewelry played a very important role in the cultural heritage of Bangladesh. Goldsmiths still are partially using ancient manufacturing process with coal fire, candle flame blowing, and nitric and sulfuric acid treatments. Such process leads to the contamination of workplace with the dust of toxic metals, acidic vapors, and particles of different natures. To evaluate contamination by particulate matter (PM), the passive particle collectors were installed in different manufacturing units for a period of 85 days at Tanti Bazar, Dhaka, Bangladesh. The laser diffraction analysis of the samples collected at the soldering units showed significant amounts of particulates, both PM10 and PM 2.5, and also nanoparticles in both nucleation and accumulation mode. SEM/EDS analysis revealed partially melted micro blebs that contain a very high concentration of Fe along with Cu. The toxic elements were detected with ICP analysis and include higher concentrations of cadmium (Cd), chromium (Cr), lead (Pb), and arsenic (As). It is notable that detection of arsenic contamination was unexpected since raw materials used for jewelry making should not have any arsenic.
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