Engineering Research Express
EISSN : 2631-8695
Published by: IOP Publishing (10.1088)
Total articles ≅ 435
Latest articles in this journal
Engineering Research Express, Volume 3; https://doi.org/10.1088/2631-8695/ac2bf0
Engineering Research Express; https://doi.org/10.1088/2631-8695/ac310e
In this work, the impact of temperature is investigated on the electrical characteristics of charge plasma-based doping-less double gate tunnel FET (DL-DG-TFET) with a low bandgap source material i.e., Si0.5Ge0.5. The influence of temperature (from 250 K to 450 K) is analysed on several performance parameters of the device such as bandgap, threshold voltage, SS, switching current ratio, ID-VGS, ID-VDS, gate current. The small change in energy bandgap with temperature reflects that device is minimally dependent on temperature. Temperature impact is significant on the sub-threshold region of transfer characteristics due to SRH recombination and trap-assisted tunnelling current. Insignificant variation of gate current with temperature signifies the better reliability of the device. Further, temperature effect is observed on analog parameters such as cut-off frequency, gate capacitance, trans-conductance, output conductance, power delay product (PDP). The minimal variation of analog parameters with temperature assures application of device in high-temperatures.
Engineering Research Express; https://doi.org/10.1088/2631-8695/ac310d
The paper presents the development and experimental investigation of recurrent neural network (RNN) based self-sensing position estimation (SSPE) model for shape memory alloy actuator (SMA). RNN used as an estimator in position feedback control loop to replace the external additional position sensor. The model was inspired from the physics-based analogy of Mass-Spring-Damper (MSD) system for antagonistic SMA wire actuator. Actuator displacement presents the hysteresis and non-linear dynamic relationship with observed differential resistance (sensing signal) during phase transformation. The resistance variation causes due to dissimilar resistivity between primary phases of SMA material. The RNN based estimation model was considered because it consists of memory element for storing the processed information and feedback connections for dynamic modelling of system. RNN was trained with input sensing signal and target displacement datasets. Estimation accuracy of model was real time evaluated during trajectory tracking of reference signals in feedback control loop. A quantitative performance analysis is assessed in terms of correlation (), mean absolute error (MEA), and root mean square error (RSME) of learned model along with developed actuator system. The tracking results confirm the close agreement between estimated and measured displacement at reasonable accuracy.
Engineering Research Express; https://doi.org/10.1088/2631-8695/ac2fae
Photon counting detectors (PCDs) offer several advantages for medical x-ray imaging compared to conventional imagers. However, current PCDs, whose circuits are fabricated using crystalline silicon semiconductor material, are not well-suited for large-area imaging applications such as breast CT and kilovoltage cone-beam CT (kV CBCT) in radiotherapy. To address this challenge, prototype PCDs based on polycrystalline silicon (a semiconductor better suited for manufacture of large-area devices) were created and, in this paper, an empirical determination of the maximum count rate of individual pixel circuit components (amplifier, comparator, clock generator and counter) corresponding to those prototypes is reported. For each circuit component, test input pulses (which were generated so as to approximate those in a complete pixel circuit) were used to obtain output response waveforms from which count rate was determined. The maximum count rate (in units of counts per second, cps) for the amplifier was determined to be 20.8 kcps while that of the comparator, clock generator and counter components were determined to be 1.2 Mcps, 98 kcps and 4.9 Mcps, respectively. The comparator and counter components provide count rates beyond that required for breast CT (~108 kcps at a pixel pitch of 330 µm) while those components as well as the clock generator exceed the rate required for kV CBCT in radiotherapy (~72 kcps at a pitch of 400 µm). It is anticipated that new polycrystalline silicon circuit designs for the amplifier and clock generator could provide count rates sufficient for both applications.
Engineering Research Express; https://doi.org/10.1088/2631-8695/ac2f54
Since gas turbine blades work in acute conditions, the study of their mechanical behavior, including impact, is one of the most important tasks recommended. The aim of this study was to investigate the impact behavior of IN738 superalloy welded by pulsed laser under different heat treatment conditions and different temperatures. The results of this study showed that the lowest fracture toughness was related to the specimens that were welded under casting conditions. This was due to the formation of liquation cracks during welding and due to the reaction between the (Ti,Ta)C carbide, γ-γ՛ eutectic, and γ՛ phase with the superalloy matrix. As the test temperature increased from ambient temperature to 600 °C, the impact toughness increased. This is attributed to the free presence of dislocations, which causes ductile behavior in the alloy. As the temperature increased further to 770 °C, the fracture toughness increased due to the increased strength of the superalloy yield due to locking of dislocations. At temperatures above 770 °C, the toughness of the superalloy was reduced again due to the decrease in strength due to the passage of dislocations through the obstacles.
Engineering Research Express; https://doi.org/10.1088/2631-8695/ac2e12
Engineering Research Express, Volume 3; https://doi.org/10.1088/2631-8695/ac2ab1
Engineering Research Express, Volume 3; https://doi.org/10.1088/2631-8695/ac2e11
Aluminum-based composites are known for better mechanical properties, superior corrosion performance, and light weight. Gradual increase in the reinforcement (SiC particles) produces improvement in several mechanical properties of Aluminum base alloy but adversely affects ductility. The present work depicts the end milling of the Al-4032/3%SiC composite. The investigation on the impact of end milling parameters has been attempted for rough and finish machining conditions. Two case studies (a) rough machining i.e., 100% weightage to material removal rate (MRR) (b) finish machining i.e., 80% weightage to surface roughness, and only 20% weightage to MRR have been investigated. Full factorial design with 3-factors at 3-level each has been used as the design matrix for conducting the milling experiments. Taguchi-based grey relational analysis (TGRA) has been adopted for the bi-objective optimization for finish machining. The significance of process parameters has been checked with analysis of variance (ANOVA).
Engineering Research Express; https://doi.org/10.1088/2631-8695/ac2e10
In this review work, various conventional cutting fluids and their application methods were discussed, which serve different functions such as cooling, lubrication, cleaning, and corrosion protection during the machining process. According to the available research, issues associated with the conventional ones were identified concerning sustainability metrics, i.e., economic, environmental, and social dimensions. These issues associated with conventional cutting fluids and application methods necessitated shifting towards a sustainable era. All such sustainable alternatives have been reviewed thoroughly, which are presently practiced in the machining process of steels as a workpiece. It can be concluded that these sustainable methods, i.e., dry cutting, minimum quantity cooling and lubrication, cryogenic lubricant, gas-based coolant, solid lubricant, etc., give better machinability performance as compared to conventional ones. However, there is a need for a trade-off between cost-effectiveness and sustainability for various combinations of cutting fluids and their application methods. The last section concludes the various sustainable methods and recommends prospects based on the demands and challenges ahead. Further, it can be concluded that knowledge of the cutting fluid types and their application methods with detailed efficiency and energy consumption models are critically important to make them commercially viable.
Engineering Research Express; https://doi.org/10.1088/2631-8695/ac2bf1
Shape memory alloy hybrid composites have promise in realizing the 21st century goal of morphing structures. There is considerable work to be done in the development of characterization and modelling techniques for these materials. The proposed characterization methodology adapts existing standards to include previously omitted factors required for the numerical modelling of shape memory alloys and their integration into end-use applications. A nickel-titanium-copper (NiTiCu) shape memory alloy is characterized using these methods and then numerically modelled. Samples' mechanical behaviour is shown to stabilize after 43 cycles of mechanical loading. Thermomechanical properties measured before and after stabilization are shown to vary inconsistently by up to 72%, demonstrating the need for stabilization for accurate thermomechanical characterizations and consistency in end-use applications. Physical experiments are numerically replicated in Abaqus\Standard using the measured properties. Sufficient correlation is shown for the design of shape memory alloy hybrid composites. The result of this work is a comprehensive thermomechanical characterization approach for shape memory alloys which can be used to develop morphing SMA hybrid composite structures.