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Active Optical Waveguides
Published in María L. Calvo, Vasudevan Lakshminarayanan, Optical Waveguides, 2018
Optical fibers as waveguides were also used in proposing and demonstrating optical memory functionality. Nonlinear Sagnac interferometers [52] have received considerable attention as possible functional devices. Originally, they employed fiber nonlinearity. However, because the nonlinearity of silica glass is very weak and required very long lengths, the semiconductor optical amplifier was later used, with the additional benefit of optical gain that turns the whole configuration into another interesting application of active optical waveguides. These designs are referred to as a semiconductor laser amplifier-in-a-loop mirror and a terahertz optical asymmetric demultiplexer. They are practically identical in construction and functionality, and operation at a bit rate of up to 1 Gb/s and an output extinction ratio of 15 dB was demonstrated. Although they can work as single-bit flip-flop type and buffer type memory, including full read and write capability, and as all-optical counters, halfadders and shift registers, the set-ups are complex and rather bulky and require a number of extra necessary components such as couplers, filters, and circulators. The systems are also bit rate-dependent and can handle only return-to-zero signals.
Optical information processing
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
In addition to interconnecting network nodes for computer or communication networks, one can consider processing data residing within the interconnect path. Such processing is generally feasible only for fiber or guided-wave interconnections. The data may be either in digital or analogue form, the former for conventional digital computer and telecommunication systems, and the latter for arrays of fiber-optic sensors. While the type of processing will vary depending on the nature of the optical fiber systems, the processing load can be expected to scale with the bandwidth of the data conveyed. With optical modulation rates now in excess of 100 GHz (see Section 4.2.1), commensurate processing speeds are required. Faster processing will allow more flexibility and capability in fiber systems, such as routing and switching a larger number of digital data channels. Use of conventional all-electronic approaches imposes a need to perform optical-to-electronic and electronic-to-optical conversions. Such conversions add complexity, and high-speed electronics will tend to be power hungry and may not provide the throughput required, e.g., due to electronic processor latencies. Hence, it is attractive to perform processing directly on the optical data stream at the transmission rate, e.g., in-fiber processing (see Section 14.2.4.3.3). The possibility of manipulating the information stream within an optical fiber has been made possible by (1) the development of optical fiber amplifiers, (2) the capability to build long fiber delay lines needed for short-duration buffer storage and for implementation of tapped delay lines, and (3) fiber couplers for tapping into delay lines and forming devices such as interferometers.
Design of Unpowered Railway Vehicles
Published in Simon Iwnicki, Maksym Spiryagin, Colin Cole, Tim McSweeney, Handbook of Railway Vehicle Dynamics, 2019
Anna Orlova, Roman Savushkin, Iurii (Yury) Boronenko, Kirill Kyakk, Ekaterina Rudakova, Artem Gusev, Veronika Fedorova, Nataly Tanicheva
Among rigid automatic couplers, couplers using the bell-and-hopper arrangement connection, which minimises the end play, have become the most widely spread (Scharfenberg patent, 1903). There are also other couplers providing connections of electric and pneumatic trainlines: Tomlinson (the USA), wedge lock couplers (Great Britain), the GF-type conical coupler (Belgium and Switzerland) and zero-clearance couplings BSU-3 (Russia).
Coupler separation of slave locomotive in a 20,000-tonne combined heavy-haul train during air-braking release
Published in Vehicle System Dynamics, 2022
Jian Wu, Liang Ling, Kun Zhou, Kang Zhou, Ertian Zhang, Kaiyun Wang, Wanming Zhai
The model includes two HX-type locomotives in the middle of the heavy-haul combined train and two C80-type wagons adjacent to the locomotives [2,26], as shown in Figure 6. The adjacent locomotive and wagon are connected by couplers/buffer systems. The No.13A type coupler and QKX100 buffer are adopted for the locomotives, while the wagons are equipped with the No. 17 type coupler and MT-2 buffer. The interaction forces between the wagons connected to slave locomotives and their adjacent wagons are simplified as longitudinal forces F1 and F2, respectively. The FASTSIM algorithm is used to solve the creep behaviour of wheel-rail contact, and the field-measured track irregularity of a heavy-haul line in China is adopted in this model. In addition, the wheel tread is JM3-type and LM-type wear tread are for the locomotive and wagon dynamics model, respectively.
An improved dynamic model of friction draft gear with a transitional characteristic accounting for housing deformation
Published in Vehicle System Dynamics, 2018
Alexander Olshevskiy, Alexey Olshevskiy, Chang-Wan Kim, Hyun-Ik Yang
Nearly, all experimental results that were used in the engineering development of draft gear PMKP-110 were obtained at the shunting hump testing facility (Figure 9). The bogie (position 3) with a mass of 44 t is lifted by the shunting winch (7) on the hump (6), uncoupled at а given height (5), which depends on the impact velocity required, and rolled against the buffer stop (2), which is fixed in the massive concrete pier (1). The impact velocity is registered by the speed sensor (8). Both the bogie and the buffer stop are equipped with automatic couplers SA-3. The draft gear is set up on the buffer stop, whereas the bogie has a rigid cast steel ingot instead of the draft gear. The impact duration and the draft gear force and deflection are registered. The draft gear force is measured using the dynamometric coupler which has the resistance strain gauges on its shank. The gauges are calibrated under the static load. The deflection of the draft gear is measured using a standard displacement indicator.
A new model for the dynamic analysis of heavy-haul locomotives with cylindrical pin coupler and buffer systems
Published in Vehicle System Dynamics, 2022
Zhichao Zhang, Gaofeng Chu, Honglin Zu, Yizhe Zhang, Gu Li
The dynamic model of the heavy-haul train with one HX-type locomotive compressed in the middle has been built up by means of the substructure method and displayed in Figure 3. This locomotive has two separate units, marked as Loco A and Loco B, and two wagons are located in the front and rear of the locomotive respectively. They are connected by three different sets of coupler and buffer substructures, i.e. ‘101 + 101’ couplers between two single locomotives, ‘101 + 17’ couplers between Loco A and the front wagon and ‘17 + 101’ ones between the rear front wagon and Loco B. The four couplers equipped by the locomotive are marked as Coupler 1 to Coupler 4. The real track irregularities measured by China Academy of Railway Science Corporation Limited are adopted and displayed in Figure 4. In order to simulate the actual locomotive compressed state, the electric brake force and measured longitudinal coupler force of the locomotive are input into the model in the following ways: (1) the torque simulating the locomotive electric brake is imposed on the centre point of every wheel set, and the equal torque in the opposite direction is input on corresponding bogie to eliminate the axle load transfer effect. (2) The longitudinal forces and obtained by Equation (13) from the measured coupler force of the middle locomotive are imposed on the front and rear ends of the whole dynamic model.