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Metal-Cutting Processes
Published in Jerry P. Byers, Metalworking Fluids, Third Edition, 2018
A further variant of drilling is tapping. Tapping cuts or forms a thread into a workpiece by removing the material from the walls of a previously drilled hole, using a tap (see Figure 3.7). Tapping is performed with a slower cutting speed than drilling, and careful attention must be paid to the axial feed so that it precisely follows the lead of the thread. Chip clearance is provided by the flutes of the tap, but the chip is generally broken by sporadic reversal and withdrawal of the tap, providing an opportunity to clear the flutes and apply fluid to the tap and hole. There are two general types of tapping operations: cut and form tapping. Cut taps make a thread by cutting the metal, generating chips in the process. Form taps make threads by pushing the metal aside, making no chips. A more lubricious fluid is necessary when form tapping, due to the higher amount of rubbing that occurs.
Numerical analysis of seismic performance of cold-formed composite walls with one-sided straw-board cladding
Published in Journal of the Chinese Institute of Engineers, 2023
Xiuhua Zhang, He Ke, Mingxin Chi, Ruochen Wang
The steel skeleton of CFSCW is made of Q235B galvanized steel plate with thicknesses of 1 and 1.5 mm, which are thin in terms of thickness. The steel plate is simulated by the shell element SHELL181. Owing to the seismic performance of CFSCW, the residual stress and initial defects of the section steel were not considered. The 58 mm thick PSB satisfies which conforms to the divided method of plate and shell structure. The PSB can be regarded as a thin plate and is simulated using the shell element SHELL181. Furthermore, according to the CFSCW experimental phenomena in the literature (Zhang et al. 2019), the self-tapping screws inside the steel skeleton were simulated by coupling simulation, and the self-tapping screws at the connection between the steel skeleton and wall panel were simulated by the spring element COMBIN39. The radial deformation of COMBIN39 in three directions was considered in the analysis, namely, the radial deformation along the two tangential directions of the wall panel and the normal phase direction of the vertical wall panel, while taking the same spring stiffness in the two tangential directions. The spring stiffness was determined by referring to the literature (Ling 2008; Yuan 2008) and the experimental conditions of CFSCW in the literature (Zhang et al. 2019). The spring stiffness curve of the self-tapping screw was modified by comparing the FEA results with the experimental results. The spring stiffness curve is shown in Figure 4.
Adaptive Neuro Fuzzy Inference System (ANFIS) based wildfire risk assessment
Published in Journal of Experimental & Theoretical Artificial Intelligence, 2019
Harkiran Kaur, Sandeep K. Sood
Global predictions for increased wildfires under a warming climate highlight the pressing need for early detection and prediction of forest fires through in-situ monitoring of fire prone areas. This can be realised by tapping the immense potential of Internet of Things (IoT), Wireless Sensor Networks (WSNs), Fog Computing (FC), Big Data Analytics and Cloud Computing (CC) in forest fire monitoring (Sood & Mahajan, 2017; Verma & Sood, 2018). In our proposed paradigm, a large number of IoT sensors are deployed in a forest block that continuously samples the environment for wildfire detection and monitoring. This leads to the generation of humungous amount of data, part of which needs to be processed in real-time for early detection of forest fire thereby minimising the losses. Several advantages of FC like low latency, heterogeneity, widespread geographical distribution, low bandwidth, etc. motivate us to use FC for earliest possible detection of wildfire outbreak and sending real-time alerts. Figure 1 depicts the three-layer architecture of FC.
Signal integrity analysis on a microstrip ultra-wideband coupled-line coupler
Published in International Journal of Electronics, 2019
Saffrine Kingsly, Sangeetha Velan, Malathi Kanagasabai, Sangeetha Subbaraj, Yogeshwari Panneer Selvam, Bhuvaneswari Balasubramaniyan
An effective comparison on the performance of the proposed coupler with the existing prototypes have been made and is given in Table 1. From the comparison table it can be inferred that the proposed prototype offers larger bandwidth with a coupling level >10 dB which is well suited for tapping and analysing the signal quality. The isolation is well above 20 dB. The proposed structure is simple, symmetric and does not require any complex characterisation technique. External structures such as EBG, FSS or metamaterials has not been used hence it can be easily constructed. The prototype does not require any lumed elements which may increase the insertion loss offered by the device. Hence, the proposed work provides a simple ultra-wide band coupler providing a fractional bandwidth of 109.5%.