Additively manufactured metals differ from their conventionally produced counterparts due to the inherent material inhomogeneity, porosity, and thermal stress induced by the process. These ...differences make the machining of additively manufactured metals more difficult and cause premature tool failure or unexpected surface finish at certain conditions. This study takes the first step to investigate and identify the causes of these issues, particularly for Ti-6Al-4V. Printed and wrought samples, as well as heat treatment effect, are compared in a dry cutting condition at a cutting speed of 90 m/min in terms of cutting power, vibration, temperature, and produced surface finish. The results show a lower cutting power and more vibration for as-printed Ti samples, indicating a less ductile microstructure and inclusion of pores. Heat treatment can eliminate these phenomena. No significant difference is found in the produced surface finish at the current cutting condition.
Post-machining is often needed to provide high dimensional accuracy and fine surface finish for additively manufactured Ti-6Al-4 V (Ti64). The material inhomogeneity, such as pores and ...microstructures, can affect the machining behavior of this already difficult-machine alloy. This study adopts a holistic approach to compare the machinability of additively manufactured and traditionally wrought Ti64 in terms of key machining factors, including forces, temperature, and vibration and the major machining outcomes including tool life, surface finish, and dimensional accuracy. Stress-relief annealing is applied to each of the part conditions as a secondary variable to observe the additional effects. The results show that AM is not particularly more difficult to machine in terms of cutting force and temperature, but it creates high cutting vibrations across a wide range of frequencies (to and over 5 kHz). The high vibrations do not lead to worse surface finish or dimensional accuracy but tend to worsen the tool life by chipping off the cutting edge. The vibration can be attributed to the brittle martensitic microstructure found in additively manufactured Ti64, which is also evidenced by the more serrated chips. Stress-relieving is found to change the microstructure and reduce the level of vibration to that of the wrought counterpart.
Post-machining is often needed to provide high dimensional accuracy and fine surface finish for additively manufactured Ti-6Al-4V (Ti64). The material inhomogeneity, such as pores and ...microstructures, can affect the machining behavior of this already difficult-machine alloy. This study adopts a holistic approach to compare the machinability of additively manufactured and traditionally wrought Ti64 in terms of key machining factors, including forces, temperature, and vibration and the major machining outcomes including tool life, surface finish, and dimensional accuracy. Stress-relief annealing is applied to each of the part conditions as a secondary variable to observe the additional effects. The results show that AM is not particularly more difficult to machine in terms of cutting force and temperature, but it creates high cutting vibrations across a wide range of frequencies (to and over 5 kHz). The high vibrations do not lead to worse surface finish or dimensional accuracy but tend to worsen the tool life by chipping off the cutting edge. The vibration can be attributed to the brittle martensitic microstructure found in additively manufactured Ti64, which is also evidenced by the more serrated chips. Stress-relieving is found to change the microstructure and reduce the level of vibration to that of the wrought counterpart.
Geothermal Energy is one of the most consistent and viable sources of renewable energy. However, harnessing this energy has proved to be a challenge mainly due to the difficulty in drilling hard ...igneous rock formations that occur in and around geothermal wells. Therefore, an energy efficient method that can drill hard rocks needs to be developed. In this paper, the effect of micro-scale energy delivery, in the form of plasma, to weaken rock by inducing micro-cracks is studied. Two different types of granite (igneous rock) were sampled and used in this study, out of which the one control group was treated with five, 40kV, 80J pulses of plasma while the other was left uncracked. The effect of the cracks is quantified by conducting facing tests on the plasma cracked and uncracked samples and measuring a reduction in the specific cutting energy. Two different methods were used to estimate the specific cutting energy, where the first method considered the entire cutting process and the second method considered only the stable cutting region. The plasma treatment showed a maximum of 65% and a minimum of 15% reduction in specific cutting energy and was regarded as being dependent on mainly the hardness and size of the samples. All results in this study are validated using statistical analysis.
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•Recent developments in multi-material additive manufacturing (MMAM) were comprehensively reviewed.•The applications of MMAM were discussed regarding various materials and AM ...methods.•The aspect of MMAM design, modeling, post-processing, and analysis was summarized.•Limitations, challenges, future trends of MMAM were highlighted.
Extensive research on nature-inspired cellular metamaterials has globally inspired innovations using single material and limited multifunctionality. Additive manufacturing (AM) of intricate geometries using multi-materials provides additional functionality, environmental adaptation, and improved mechanical properties. Recently, several studies have been conducted on multi-material additive manufacturing (MMAM) technologies, including multi-materials, methodologies, design, and optimization. However, in the past six years, very few or no systematic and complete reviews have been conducted in this research domain. This review intends to comprehensively summarize MMAM systems and the working principles of its fundamental processes. Herein, the Multi-material combinations and their design, modeling, and analysis strategies have been reviewed systematically. In particular, the focus is on applications and opportunities for using MMAM for several industries and postprocessing MMAM fabricated parts. Furthermore, this review identified the limitations and challenges of existing software packages, MMAM processes, materials, and joining mechanisms, especially at the multi-material interfaces. Finally, we discuss the possible strategies to overcome the aforementioned technological challenges and state the future directions, which will provide insights to researchers and engineers designing and manufacturing complex nature-inspired objects.
Organic electronics has been a popular field for the last two decades, due to its potential to commercialize cheap-price and large-area flexible electronics. The devices based on organic compounds ...heavily rely on organic semiconductors (OSs). Primary challenge for materials chemist is the new OSs construction that has ameliorated attainment in organic thin film transistors (OTFTs) and organic field effect transistors (OFETs). The construction of air-stable (stable in air) n-channel OSs (electron-conducting materials) is particularly needed with capability comparable to that of p-channel materials (hole-conducting materials). In the last 10 years, there have been significant advancements in thiophene-based OSs. Thiophene-mediated molecules have a prominent role in the advancement of OSs. The main significance in thiophene-based molecules is their cheap-price (in comparison to silicon), processability at low temperature, structural flexibility, ability to be applied on flexible substrates, and high charge transport characteristics. In this paper, we review the progress in the performance of thiophene-based OSs that has been reported in the last 18 years, with a major emphasis on the last 10 years. This approach provides a crisp introduction to organic devices and catalogs progress toward the fabrication of thiophene containing p, n and ambipolar channel OSs, and discusses their characteristics. Finally, review discusses current challenges and future research directions for thiophene based OSs. This review would be beneficial for further developments in the technological performance. Moreover, this review will serve to accelerate knowledge and lays the foundation for improved applications. Hopefully, this struggle pushes the reader’s mind to consider new perspectives, think differently and forge new connections.
Halogenated and non-halogenated N-(4-phenyl-3-aroyl-2(3H)-ylidene) substituted acetamides were prepared by base-catalyzed cyclization of corresponding acetyl thioureas with phenacyl bromide. The ...synthesized compounds were structurally characterized by 1H NMR and 13C NMR spectroscopy and were screened against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzyme inhibition activities. Molecular docking studies, drug-like profiling and kinetic analysis were performed to further investigate the inhibition mechanism of the compounds. This study provided useful insights into the design and development of novel dual inhibitors, in addition to understanding the mechanism by which such drugs interact with targets and exert their biochemical action. All the compounds showed superior inhibition profile compared to the standards possessing sub-micromolar and micromolar IC50 values for AChE and BChE, respectively. Docking simulations revealed that the compound 6g showed strong binding inside the active site gorges of both AChE and BChE. An excellent agreement was obtained as the best docked poses showed important binding features mostly based on interactions due to aromatic moieties and oxygen atoms of the compound. Cation-pi/pi-pi interactions together with hydrogen bond forces were the key players responsible for ligand anchoring in the active sites. The striking results accomplished both in docking computations and experimental findings ascertained that the compound 6g can serve as a scaffold for both AChE and BChE inhibition.
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•A series of halogenated and non-halogenated N-(4-phenyl-3-aroyl-2(3H)-ylidene) substituted acetamides was synthesized.•The compounds showed excellent activity against AChE and (BChE) inhibition.•Computation results revealed compounds are potent surrogates for neurodegenerative diseases.
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•Sonogashira coupling reaction was used to synthesized novel silicon containing alkyne compounds.•Synthesized compounds were evaluated against carbonic anhydrase II enzyme.•Binding ...analysis and pharmacokinetics was explored.
A novel series of silyl-yne containing chalcone derivatives 5a-5j was synthesized by exploiting Sonogashira coupling reaction and Claisen-Schimdt condensation reaction. The synthesized derivative were characterized by spectroscopic and elemental analysis. The selective inhibition of carbonic anhydrases is considered critical in the field of medicinal chemistry because carbonic anhydrases exits in several isoforms. Synthesized compounds were subjected to carbonic anhydrase –II assay. Except 5j, the other derivatives exhibited better potential than standard acetazolamide. Compound 5e was found to be potent derivative in the series with IC50 value 0.054 ± 0.001 µM. Binding analysis revealed that most potent derivative 5e binds in the active site of CA-II and single π-π stacking interaction was observed between ring structure of ligand and Phe129 having bond length 4.90 Å. Pharmacokinetics elicited that compounds obey Lipinski’s rule and show significant drug score.
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