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Best Practices in Construction and Demolition Waste Management
Published in Ashok K. Rathoure, Zero Waste, 2019
As per Construction and Demolition (C&D) Waste Management Rules 2016, construction means the process of erecting of building or built facility or other structure, or building of infrastructure including alteration. As per Construction and Demolition Waste Management Rules 2016, demolition means breaking down or tearing down buildings and other structures either manually or using mechanical force (by various equipment) or by implosion using explosives. As per Construction and Demolition Waste Management Rules 2016, construction and demolition waste means the waste comprising building materials, debris and rubble resulting from construction, remodelling, repair and demolition of any civil structure. Waste is generated at different stages of the construction process. Waste during construction activity relates to excessive cement mix or concrete left after work is over, rejection/demolition caused due to change in design or wrong workmanship and so forth. Construction waste is bulky, heavy and mostly unsuitable for disposal by incineration or composting (Patel et al., 2014).
Demolition
Published in Erik K. Lauritzen, Construction, Demolition and Disaster Waste Management, 2018
In cases of very thick constructed structures or high structures, demolition using explosives placed in drill holes can be applied. Demolition of buildings by blasting can be performed as overturning of the structure or as vertical progressive collapse called implosion; see examples in Section 3.7 and Figures 3.11 and 3.12.
Trinity by the Numbers: The Computing Effort that Made Trinity Possible
Published in Nuclear Technology, 2021
The first implosion simulations on the PCAM equipment explored different configurations of the implosion device and its components. These exploratory simulations were used to select a configuration for detailed modeling, which then informed the selection of a design for construction into a working device. Calculating the weapon’s explosive efficiency and yield followed. An implosion simulation began with modeling the detonation of the weapon’s high-explosive charge, then it followed the resulting shockwave as it propagated through the core and reflected back. The calculations had to be transferred to human computers when the shockwave encountered a boundary between two materials due to the complexity of the interface calculations. The human computers in this operation fulfilled a similar role as the accelerators found in current heterogeneous high-performance computing systems. Once the simulated shockwave returned to a uniform material, the calculations went back to the punched-card machines. Interface calculations were only one of the many points where operators had to intervene with the machines, locating errors was another.10,12,14,18
The Trinity High-Explosive Implosion System: The Foundation for Precision Explosive Applications
Published in Nuclear Technology, 2021
Eric N. Brown, Dan L. Borovina
Following the summer of 1944, several experimental diagnostics were advanced and developed to characterize, and iteratively improve, the converging implosion lens system of the Christy Gadget. The Radioactive Lanthanum or RaLa experiment measured changes of absorption of gamma rays from large quantities of a short-lived radioisotope 140La to measure the spherical implosion caused by converging explosive shock waves. This novel diagnostic of implosion was based on placing a gamma-ray source at the center of a spherical implosion assembly. The emitted gamma rays would travel outward radially. Because increasing compression of the metal caused the gamma rays to be increasingly absorbed, the emerging gamma rays, monitored by detectors set around the HEs, would provide information on density changes in the collapsing sphere of metal. The data would indicate the time of collapse, the degree of compression, and the symmetry, by comparing the gamma-ray intensity in different directions.7
Determination of the Oxygen Concentration in GDP Thin Films Using Rutherford Backscattering Spectroscopy
Published in Fusion Science and Technology, 2021
Xiaojun Ma, Qi Wang, Zongwei Wang, Xiangyu Wan
Owing to its surface roughness of nanometer scale, excellent thermal stability, and transparency to visible light, which is particularly important for characterizing the capsule parameters, the glow discharge polymer (GDP) capsule is proposed as one of the alternative ignition design capsules. There are a large number of dangling bonds and unsaturated bonds on the surface of the GDP capsule due to the discontinuity of the interface. The corresponding bonds easily react with the water vapor in the air, consequently, there is a substantial increase in the oxygen atom concentration on the outer surface. The adsorbed oxygen atoms gradually diffuse in the GDP material and form an oxygen profile distribution with an exponentially decaying functional relation in the radial direction of the capsule. In implosion experiments, a precisely timed sequence of shocks is used to compress the capsule to improve implosion performance. Unfortunately, the surface oxygen adds X-ray opacity of GDP material and affects the shock velocity in GDP material. To reach the ignition condition, the disturbance originated from surface oxygen needs to be compensated for in the shock timing, therefore, it is of particular importance to measure accurately the oxygen atom content of GDP capsules.