The regulated Metal Deposition (RMD™) process is a variant of the gas metal arc welding process (GMAW), which was developed to effectively control the metal transfer in the short-circuiting mode. The ...process is fundamentally a modified short-circuit GMAW process wherein a uniform droplet deposition, making it easier for the welder to control the puddle and hence achieve an enhanced quality of welded joints. In the present study, the RMD technique has been established for the low alloy steel grade 2.25 Cr - 1.0 Mo particularly for depositing the root pass on a 10 mm thick joint. In addition to this, the RMD technique is attempted with metal-cored wires to enhance the deposition rates and hence productivity. The joint fill-up is further attempted with the GMAW technique using metal-cored wires and analysed. The weldments were subjected to post-weld heat treatment followed by mechanical and metallurgical characterization. Mechanical characterization such as tensile properties, impact properties, bend test as well as all weld tensile properties of the weld joint was evaluated and found to be acceptable. The ductile to brittle transition temperature (DBTT) testing was carried out by breaking series of impact specimen till negative temperatures. The DBTT temperature for the weld joint was found well below −30 °C which indicated the strength and soundness of the welded joint. Optical microscopy and scanning electron microscopy was carried out for and favourable results were achieved in microanalysis. The study proposes the use of metal-cored wires for potential applications in the welding of high thickness joints for enhancing the overall productivity.
AA 2024 alloy is widely used as a structural material in aerospace applications. Its excellent strength to weight ratio makes it suitable for the subsequent application. The aerospace application ...required close tolerances and accuracy in the machined parts. Henceforth non-conventional machining processes are widely used for different machining operations such as drilling through holes. In the present study, Electrical Discharge Machining (EDM) process is used to drill through holes in 5mm thick AA 2024 alloy material. With the aim of reducing the difference between finished diameter of drilled hole and intended diameter, computational technologies were adopted for optimization. Mathematical models were developed using Response Surface methodology (RSM), and subsequently Genetic Algorithm (GA) was used to reach a set of input parameters in order to give minimum difference in diameter. Three input parameters such as current (I), Pulse on time (Ton) and Pulse off time (Toff) were selected. The ANOVA results indicated that developed models were adequate and robust. The GA based approach in conjugation with RSM was able to locate a single set of parameters which gave minimum difference in diameter. Confirmation test was again carried out and the difference between predicted and measured value was negligible.
During milling operations, wear of cutting tool is inevitable; therefore, tool condition monitoring is essential. One of the difficulties in detecting the state of milling tools is that they are ...visually inspected, and due to this, the milling process needs to be interrupted. Intelligent monitoring systems based on accelerometers and algorithms have been developed as a part of Industry 4.0 to monitor the tool wear during milling process. In this paper, acoustic emission (AE) and vibration signals captured through sensors are analyzed and the scalograms were constructed from Morlet wavelets. The relative wavelet energy (RWE) criterion was applied to select suitable wavelet functions. Due to the availability of less experimental data to train the LSTM model for the prediction of tool wear, SinGAN was applied to generate additional scalograms and later several image quality parameters were extracted to construct feature vectors. The feature vector is used to train three long short-term memory network (LSTM) models: vanilla, stacked, and bidirectional. To analyze the performance of LSTM models for tool wear prediction, five performance parameters were computed namely
R
2
, adjusted
R
2
, mean absolute error (MAE), root mean square error (RMSE), and mean square error (MSE). The lowest MAE, RMSE, and MSE values were observed as 0.005, 0.016, and 0.0002 and high
R
2
and Adj.
R
2
values as 0.997 are observed from the vibration signal. Results suggest that the stacked LSTM model predicts the tool wear better as compared to other LSTM models. The proposed methodology has given very less errors in tool wear predictions and can be extremely useful for the development of an online deep learning tool condition monitoring system.
This paper implements Teaching-Learning based optimization (TLBO) to obtain optimized value of spring stiffness for better ride comfort. Further, this optimized value is then used in a semi-active ...quarter car setup to remove any discrepancies due to non-optimized spring. This paper also introduces a novel approach to control the Semi-active suspension parameter (damping coefficient) for a better performance. For controlling semi-active parameters, PID controller has been used. PID controller output is fed to the quarter car setup as a damping coefficient. Thus changing the damping coefficient dynamically as the disturbance occurs, and thus improving the ride comfort. The sprung mass acceleration and rattle space of semi-active quarter car has been compared with sprung mass acceleration and rattle space of passive quarter car model to show the difference in results and thereby, results and conclusions are drawn.
In this work, a modified and advanced welding technique named regulated metal deposition (RMD) has been implemented for joining ASTM A387-11-2 low alloy steel plates. Mechanical behavior and ...microstructure of welded joints have been experimentally investigated after the recommended heat-treatment process. The microstructures of welded joints were examined using optical and scanning electron microscopes. Optical microscopy indicated the existence of bainitic and martensitic phases in the base material and weld zone, respectively. Scanning electron microscopy combined with energy dispersive x-ray analysis displayed the presence of martensitic colonies as well as deposits of carbide precipitates in both weldments. The mechanical properties of these weldments, namely micro-hardness, tensile strength, and impact strength were also investigated. A comparative study has also been carried out for the same material using the conventional gas metal arc welding, in which the microstructure and mechanical behavior of regulated metal deposition weldments have been compared to those of gas metal arc weldments. Regulated metal deposition weldments showed better mechanical behavior than the gas metal arc weldments for low alloy steel.
In the present study activated tungsten inert gas welding (A-TIG) process has been attempted for welding of 6mm thick reduced activation ferritic/martensitic (RAFM) steel. Comparative studies on the ...effect of single (760°C for 2h) and double (760°C for 2h+760°C for 2h) post-weld heat treatment (PWHT) cycles on microstructures, microhardness, tensile strength, impact strength and ductile to brittle transition temperatures (DBTT) of these welded joints have also been evaluated. It was inferred from the studies that ductility was improved for the weldments after undergoing double PWHT cycles. The toughness values increased after double PWHT cycles and were comparable to that of base metal values. DBTT values of −5°C and −11°C were obtained for the welded samples undergone single and double PWHT cycles respectively. This study also attested the detailed structure–property relationship of A-TIG weldments using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy (EDS) techniques.
In this study, hierarchical composites of Titania-graphene nanograss arrays (TiO2@Gr) on shape memory alloy were prepared via chemical vapor deposition-controlled growth process (camphor as source) ...and subsequent hydrothermal method. The TiO2@Gr composite composition was optimized by varying the concentrations of graphene on TiO2 nanograss grown over shape memory alloy. The optical, surface, and structural studies of as-prepared TiO2@Gr composite were performed under UV–vis spectroscopy, Field Emission Scanning Electron Microscope, Transmission Electron Microscope, Raman, X-ray diffraction and X-ray photoelectron spectroscopy. The result revealed the formation of pure rutile phase Titania nanograss with the impregnation of graphene sheets. Further, the impregnated graphene-Titania composite samples were used as photoanodes (photoelectrode) in 1 M potassium hydroxide solution for photoelectrochemical application. The results revealed an enhancement in photocurrent density of 1.82 mA/cm2 at 1.23 V vs. reversible hydrogen electrode, signifying excellent photoelectrochemical performance superior to that of pure rutile titania (nearly 3.5 times), which is attributed to a synergetic effect of the improved electron-hole pair separation rate leading to superior charge transfer due to the presence of graphene nanosheets. Transient photo-response studies (TPS) and Electrochemical impedance spectroscopy (EIS) were used to study the effective charge transfer response and interfacial charge transfer process respectively. The approach for the fabrication of the hierarchical nanocomposite in this study may drive the way for designing innovative composite materials for enhanced photoelectrochemical performance.
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•Intergating CVD and hydrothermal techniques to fabricate TiO2@Gr composite.•Enhanced photocurrent density of ∼1.8 mA/cm2, which is ∼3 times higher than R–TiO2.•Insight into the role of graphene in enhancing the overall efficiency of system.•TPS and EIS studies show enhanced charge transfer kinetics for TiO2@Gr composite.
Regulated Metal Deposition (RMD™) welding process is fundamentally a modified short-circuit gas metal arc welding (GMAW) process wherein a precisely-controlled metal transfer provides uniform droplet ...deposition, making it easier for the welder to control the puddle and hence achieve an enhanced quality of welded joints. RMD technique was experimented and implemented on a variety of steels such as stainless steel, carbon steels, etc. However, obtaining satisfactory welding performance is indeed a challenging task during RMD. Hence, this study aims to assess the favorable parameters settings in order to optimize welding performance characteristics such as Heat affected zone (HAZ), depth of penetration (DOP) and bead width (BW) of Regulated Metal Deposited arc weldment using grey relation analysis integrated with fuzzy inference system with Taguchi approach. From the adopted methodology the optimal parameter settings for current (135 A), voltage (14 V), and gas flow rate (13 L/min) have been achieved. The study also tells that the voltage is the most influencing parameter during RMD welding.
TN-301 is a highly selective, orally available histone deacetylase 6 (HDAC6) inhibitor being developed for the potential treatment of heart failure with preserved ejection fraction (HFpEF). Studies ...in preclinical models show reversal of HFpEF disease by selective HDAC6 inhibition. This First-in-Human (FiH) Phase 1 clinical trial evaluates the safety and biological activity of TN-301 at a broad range of single doses and multiple daily doses over 2 weeks in healthy adult participants.
Multiple preclinical models of HFpEF suggest that selective HDAC6 inhibition has direct and systemic effects on multiple pathways linked to HFpEF pathogenesis, including mitochondrial dysfunction, fibrosis and inflammation, while avoiding undesirable effects of non-selective HDAC inhibitors. This FiH study is designed to identify a dose range for further development and to demonstrate potential clinical utility through use of relevant biomarkers.
The double-blinded, randomized clinical trial plans to enroll 72 participants in 6 single-ascending dose (SAD) and 3 multiple-ascending dose (MAD) cohorts, each comprised of 8 participants (6 active, 2 placebo). MAD cohorts are dosed once daily for 14 consecutive days. Endpoints include safety, tolerability, pharmacokinetic (PK) and pharmacodynamic (PD) assessments. A key PD biomarker of HDAC6 inhibition is the level of acetylated tubulin in PMBCs.
Comprehensive synthesis of unblinded safety, tolerability, PK, and PD results, including additional planned cohorts, are anticipated by the time of presentation. As of the submission of this abstract, 48 participants have been randomized into the SAD stage and received TN-301 or placebo per protocol at oral doses from 1-700mg. An additional 16 participants have been treated in 2 MAD cohorts at 25mg and 100mg. Among these participants, there were no SAEs, DLTs or premature withdrawals due to tolerability. Interim analysis showed a slightly more than dose-proportional PK profile with a half-life consistent with once-daily dosing. Plasma concentrations were attained that corresponded with those observed in mouse models that demonstrated robust PD affects and reversal of HFpEF phenotype. Target engagement was demonstrated at doses >5mg and was sustained above baseline throughout the dosing interval in the MAD cohorts at steady state.
Initial data from this FiH clinical trial of TN-301 in healthy adult participants demonstrated clear evidence of target engagement. To date, TN-301 has been generally well tolerated with PK consistent with once-daily dosing. TN-301 represents a promising new therapeutic candidate for the potential treatment of HFpEF and other indications.
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•Inexpensive CVD method to fabricate R-TiO2 Nanorods over NiTi using camphor as source.•An insight to growth mechanism of high-purity TiO2 Nanorods.•Role of camphor and factors ...affecting the CVD growth process is demonstrated using COMSOL simulation.•Dependency of TiO2 NR morphology over camphor concentration and temperature.•Fabrication of photoanode for efficient energy harvesting application.
We demonstrated a cost-effective and scalablechemical vapor deposition(CVD) process for the production of high quality and dense rutile titanium dioxide nanorods (R-TiO2 NR) based on camphor (Cinnamomum camphora) decomposition overshape memory alloy (nitinol). The topography of the camphor-based R-TiO2 NR was studied underfield emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) which revealed high coverage of R-TiO2 NR over the substrate. The phase purity of R-TiO2 NR was established by X-ray diffraction measurements performed at different camphor concentrations and substrate temperatures. Raman spectroscopy and X-ray photoelectron spectroscopyconfirmed the chemical and the elemental composition of the nanorods grown over nitinol, which suggest the formation of high-quality R-TiO2 NR. Further, R-TiO2 NR was used as photoanode in 1 M KOH solution for efficient energy harvesting application by indicating a high photocurrent density of 550 µA/cm2 at 1.23 V vs RHE (reversible hydrogen electrode), indicating excellent light trapping mechanism with efficient charge separation and extraction. The proposed CVD process is a suitable method for large scale production of R-TiO2 NR over nitinol, which can be potentially employed in sensors and various other biomedical applications.
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