Enhanced structural integrity of Laser Powder Bed Fusion based AlSi10Mg parts by attaining defect free melt pool formations.

This research aims to fabricate an AlSi10Mg parts using Laser Powder Bed Fusion technique with enhanced structural integrity. The prime novelty of this research work is eliminating the balling and sparring effects, keyhole and cavity formation by attaining effective melt pool formation. Modelling of the Laser Powder Bed Fusion process parameters such as Laser power, scanning speed, layer thickness and hatch spacing is carried out through Complex Proportional Assessment technique to optimize the parts' surface attributes and to overcome the defects based on the output responses such as surface roughness on scanning and building side, hardness and porosity. The laser power of 350 W, layer thickness of 30 µm, scan speed of 1133 mm/s, and hatch spacing of 0.1 mm produces significantly desirable results to achieve maximum hardness and minimum surface roughness and holding the porosity of < 1%. The obtained optimal setting from this research improves the structural integrity of the printed AlSi10Mg parts.

Electric Discharge Machining of Ti6Al4V ELI in Biomedical Industry: Parametric Analysis of Surface Functionalization and Tribological Characterization.

The superior engineering properties and excellent biocompatibility of titanium alloy (Ti6Al4V) stimulate applications in biomedical industries. Electric discharge machining, a widely used process in advanced applications, is an attractive option that simultaneously offers machining and surface modification. In this study, a comprehensive list of roughening levels of process variables such as pulse current, pulse ON time, pulse OFF time, and polarity, along with four tool electrodes of graphite, copper, brass, and aluminum are evaluated (against two experimentation phases) using a SiC powder-mixed dielectric. The process is modeled using the adaptive neural fuzzy inference system (ANFIS) to produce surfaces with relatively low roughness. A thorough parametric, microscopical, and tribological analysis campaign is established to explore the physical science of the process. For the case of the surface generated through aluminum, a minimum friction force of ~25 N is observed compared with the other surfaces. The analysis of variance shows that the electrode material (32.65%) is found to be significant for the material removal rate, and the pulse ON time (32.15%) is found to be significant for arithmetic roughness. The increase in pulse current to 14 A shows that the roughness increased to ~4.6 µm with a 33% rise using the aluminum electrode. The increase in pulse ON time from 50 µs to 125 µs using the graphite tool resulted in a rise in roughness from ~4.5 µm to ~5.3 µm, showing a 17% rise.

Achieving effective interlayer bonding of PLA parts during the material extrusion process with enhanced mechanical properties.

The additive manufacturing technique of material extrusion has challenge of excessive process defects and not achieving the desired mechanical properties. The industry is trying to develop certification to better control variations in mechanical attributes. The current study is a progress towards understanding the evolution of processing defects and the correlation of mechanical behavior with the process parameters. Modeling of the 3D printing process parameters such as layer thickness, printing speed, and printing temperature is carried out through L27 orthogonal array using Taguchi approach. In addition, CRITIC embedded WASPAS is adopted to optimize the parts' mechanical attributes and overcome the defects. Flexural and tensile poly-lactic acid specimens are printed according to ASTM standards D790 and D638, respectively, and thoroughly analyzed based on the surface morphological analysis to characterize defects. The parametric significance analysis is carried out to explore process science where the layer thickness, print speed, and temperature significantly control the quality and strength of the parts. Mathematical optimization results based on composite desirability show that layer thickness of 0.1 mm, printing speed of 60 mm/s, and printing temperature of 200 °C produce significantly desirable results. The validation experiments yielded the maximum flexural strength of 78.52 MPa, the maximum ultimate tensile strength of 45.52 MPa, and maximum impact strength of 6.21 kJ/m2. It is established that multiple fused layers restricted the propagation of cracks with minimum thickness due to enhanced diffusion between the layers.

Utilizing bio-waste as the reinforcement particles for the production of sustainable composite brakes and the investigation of its tribological and corrosive performance.

The goat population has been growing faster than the overall human population over the past couple of decades, particularly in African countries and Southeast Asia. As a result, there has been a sharp rise in bio-waste. So, this holistic research aims to convert the goat dung into a sustainable composite material with enhanced morphological, tribological, and corrosive properties. Al8011 alloy serves as the matrix material for the synthesized hybrid composites, and goat dung ash (GDA) and silicon nitride (Si3N4) serve as the reinforcing particles in varying ratios ranging from 0 to 10%. Microstructural analysis was performed to estimate the grain size distribution using ImageJ software. The inclusion of GDA particles along with the Si3N4 particles decreases the grain size from 18 to 9 µm. Similarly, 56.26% reduction of wear rate was evident due to the lubricating nature of the GDA particles. The plowing, delamination, and wear debris were examined in the worn-out surface of the wear specimens. Corrosion behavior was analyzed using the weight-loss gravimetric technique. The included GDA particles created a stable oxide layer that resists corrosion and it was proved by the microscopic analysis on the corroded surface. In the break shoe performance analysis, the fabricated Al8011(Si3N4 + GDA) composite brake lining material shows 23% more wear resistance when compared with the existing (Al6061-10% SiC) brake lining material. This minimal wear in the brake shoe not only assures their sustainability, but also tends to minimize wear-related emissions and economic losses.

Erratum: Publisher Correction: Additive manufacturing for biomedical applications: a review on classification, energy consumption, and its appreciable role since COVID-19 pandemic.

[This corrects the article DOI: 10.1007/s40964-022-00373-9.].

A Novel Flushing Mechanism to Minimize Roughness and Dimensional Errors during Wire Electric Discharge Machining of Complex Profiles on Inconel 718.

One of the sustainability goals in the aeronautical industry includes developing cost-effective, high-performance engine components possessing complex curved geometries with excellent dimensional precision and surface quality. In this regard, several developments in wire electric discharge machining have been reported, but the influence of flushing attributes is not thoroughly investigated and is thus studied herein. The influence of four process variables, namely servo voltage, flushing pressure, nozzle diameter, and nozzle-workpiece distance, were analyzed on Inconel 718 in relation to geometrical errors (angular and radial deviations), spark gap formation, and arithmetic roughness. In this regard, thorough statistical and microscopical analyses are employed with mono- and multi-objective process optimization. The grey relational analysis affirms the reduction in the process's limitations, validated through confirmatory experimentation results as 0.109 mm spark gap, 0.956% angular deviation, 3.49% radial deviation, and 2.2 µm surface roughness. The novel flushing mechanism improved the spark gap by 1.92%, reducing angular and radial deviations by 8.24% and 29.11%, respectively.

Additive manufacturing for biomedical applications: a review on classification, energy consumption, and its appreciable role since COVID-19 pandemic.

The exponential rise of healthcare problems like human aging and road traffic accidents have developed an intrinsic challenge to biomedical sectors concerning the arrangement of patient-specific biomedical products. The additively manufactured implants and scaffolds have captured global attention over the last two decades concerning their printing quality and ease of manufacturing. However, the inherent challenges associated with additive manufacturing (AM) technologies, namely process selection, level of complexity, printing speed, resolution, biomaterial choice, and consumed energy, still pose several limitations on their use. Recently, the whole world has faced severe supply chain disruptions of personal protective equipment and basic medical facilities due to a respiratory disease known as the coronavirus (COVID-19). In this regard, local and global AM manufacturers have printed biomedical products to level the supply-demand equation. The potential of AM technologies for biomedical applications before, during, and post-COVID-19 pandemic alongwith its relation to the industry 4.0 (I4.0) concept is discussed herein. Moreover, additive manufacturing technologies are studied in this work concerning their working principle, classification, materials, processing variables, output responses, merits, challenges, and biomedical applications. Different factors affecting the sustainable performance in AM for biomedical applications are discussed with more focus on the comparative examination of consumed energy to determine which process is more sustainable. The recent advancements in the field like 4D printing and 5D printing are useful for the successful implementation of I4.0 to combat any future pandemic scenario. The potential of hybrid printing, multi-materials printing, and printing with smart materials, has been identified as hot research areas to produce scaffolds and implants in regenerative medicine, tissue engineering, and orthopedic implants.

Progressing towards Sustainable Machining of Steels: A Detailed Review.

Machining operations are very common for the production of auto parts, i.e., connecting rods, crankshafts, etc. In machining, the use of cutting oil is very necessary, but it leads to higher machining costs and environmental problems. About 17% of the cost of any product is associated with cutting fluid, and about 80% of skin diseases are due to mist and fumes generated by cutting oils. Environmental legislation and operators' safety demand the minimal use of cutting fluid and proper disposal of used cutting oil. The disposal cost is huge, about two times higher than the machining cost. To improve occupational health and safety and the reduction of product costs, companies are moving towards sustainable manufacturing. Therefore, this review article emphasizes the sustainable machining aspects of steel by employing techniques that require the minimal use of cutting oils, i.e., minimum quantity lubrication, and other efficient techniques like cryogenic cooling, dry cutting, solid lubricants, air/vapor/gas cooling, and cryogenic treatment. Cryogenic treatment on tools and the use of vegetable oils or biodegradable oils instead of mineral oils are used as primary techniques to enhance the overall part quality, which leads to longer tool life with no negative impacts on the environment. To further help the manufacturing community in progressing towards industry 4.0 and obtaining net-zero emissions, in this paper, we present a comprehensive review of the recent, state of the art sustainable techniques used for machining steel materials/components by which the industry can massively improve their product quality and production.

An efficient triazole-based fluorescent "turn-on" receptor for naked-eye recognition of F- and AcO-: UV-visible, fluorescence and 1H NMR studies.

An efficient colorimetric receptor was developed by a simple convenient method which exhibited naked-eye sensitivity for fluoride and acetate in a biologically competing solvent like DMSO. The receptor developed, portrayed a substantial change in the UV-visible absorption characteristics upon addition of fluoride and acetate anions over other anions. The binding constants showed that the binding ability of receptor towards F(-) anion was slightly higher than that of the AcO(-) anion. Job's plots indicated the formation of a (1:1) complex (receptor:anion) of receptor with fluoride and acetate anions respectively. A "turn on" fluorescence response with a red shift was observed upon fluorescence titration. (1)H NMR titration experiments revealed the mechanism to be driven by the hydrogen bonding interaction of amide NH and phenol OH of the receptor molecule which was followed by deprotonation in the receptor by the F(-) and AcO(-) anions.

1, 5-Bis (2-hydroxyacetophenone)thiocarbohydrazone: a novel colorimetric and fluorescent dual-mode chemosensor for the recognition of fluoride.

1,5-Bis (2-hydroxyacetophenone)thiocarbohydrazone (H4L) has been synthesized and characterized by means of spectroscopic and single crystal X-ray diffraction methods. Interactions of the H4L with a variety of anions were investigated using a combination of UV-visible and fluorescence spectroscopic methods in a biological competing solvent DMSO. The H4L has a high degree of selectivity for fluoride over other anions. (1)H NMR titration experiments indicate that a deprotonation process is involved in the chemo sensing process.

DNA Damage Protecting Activity and Free Radical Scavenging Activity of Anthocyanins from Red Sorghum (Sorghum bicolor) Bran.

There is increasing interest in natural food colorants like carotenoids and anthocyanins with functional properties. Red sorghum bran is known as a rich source for anthocyanins. The anthocyanin contents extracted from red sorghum bran were evaluated by biochemical analysis. Among the three solvent system used, the acidified methanol extract showed a highest anthocyanin content (4.7 mg/g of sorghum bran) followed by methanol (1.95 mg/g) and acetone (1 mg/g). Similarly, the highest total flavonoids (143 mg/g) and total phenolic contents (0.93 mg/g) were obtained in acidified methanol extracts than methanol and acetone extracts. To study the health benefits of anthocyanin from red sorghum bran, the total antioxidant activity was evaluated by biochemical and molecular methods. The highest antioxidant activity was observed in acidified methanol extracts of anthocyanin in dose-dependent manner. The antioxidant activity of the red sorghum bran was directly related to the total anthocyanin found in red sorghum bran.

4-Salicylideneamino-3-methyl-1,2,4-triazole-5-thione as a sensor for aniline recognition.

Tridentate triazole based Schiff base 4-salicylideneamino-3-methyl-1,2,4-triazole-5-thione has been found to selectively detect toxic aromatic amines such as aniline and benzene-1,4-diamine by simple titration techniques like UV-visible, fluorescence spectral studies (PL) and 1H NMR titrations. The Schiff base receptor utilizes, thione sulfur, NH-thione and the phenolic hydroxyl group to form hydrogen bonded adduct of aniline and benzene-1,4-diamine with high binding affinity, followed by a slow removal of the corresponding hydrogens thus providing a promising candidate and an unique receptor for toxic aromatic amines.

Evaluation of antiproliferative activity of red sorghum bran anthocyanin on a human breast cancer cell line (mcf-7).

Breast cancer is a leading cause of death in women worldwide both in the developed and developing countries. Thus effective treatment of breast cancer with potential antitumour drugs is important. In this paper, human breast cancer cell line MCF-7 has been employed to evaluate the antiproliferative activity of red sorghum bran anthocyanin. The present investigation showed that red sorghum bran anthocyanin induced growth inhibition of MCF-7 cells at significant level. The growth inhibition is dose dependent and irreversible in nature. When MCF-7 cells were treated with red sorghum bran anthocyanins due to activity of anthocyanin morphological changes were observed. The morphological changes were identified through the formation of apoptopic bodies. The fragmentation by these anthocyanins on DNA to oligonuleosomal-sized fragments, is a characteristic of apoptosis, and it was observed as concentration-dependent. Thus, this paper clearly demonstrates that human breast cancer cell MCF-7 is highly responsive by red sorghum bran anthocyanins result from the induction of apoptosis in MCF-7 cells.

Identification, isolation and characterization of process-related impurities in Rizatriptan benzoate.

Three process-related impurities were observed in routine monitoring of the samples by HPLC. These impurities were identified by LC-MS. One of the impurities, Imp-3 [rizatriptan-2,5-dimer] was reported in literature. Other two impurities were isolated by preparative HPLC and characterized by NMR, Mass and IR. Pure impurities obtained by isolation were co-injected with Rizatriptan benzoate sample to confirm the retention times in HPLC. Structure elucidation of these impurities by spectral data has been discussed in detail. These impurities were identified as 4-(5-((1H-1,2,4-triazol-1-yl)methyl)-3-(2-(dimethylamino)ethyl)-1H-indol-1-yl)-4-(5-((1H-1,2,4-triazol-1-yl)methyl)-3-(2-(dimethylamino)ethyl)-1H-indol-2-yl)-N,N-dimethylbutan-1-amine [rizatriptan-1,2-dimer] and [4,4-bis-(5-((1H-1,2,4-triazol-1-yl)methyl)-3-(2-(dimethylamino)-ethyl)-1H-indol-2-yl)-N,N-dimethylbutan-1-amine [rizatriptan-2,2-dimer].

Identification, isolation and characterization of potential degradation product in risperidone tablets.

One unknown impurity (degradation product) present at a level below 0.1% in the initial samples increased to a level of 0.5% in 6M/40 degrees C/75% RH stability samples of risperidone tablets was detected by gradient reverse-phase high-performance liquid chromatography (HPLC). This impurity was isolated using reverse-phase preparative liquid chromatography. Based on the spectral data the structure of this impurity is characterized as 3-[2-[4-[6-fluoro-1,3-benzoxazol-2-yl]piperidin-1-yl]ethyl]-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a] pyrimidin-4-one. Structural elucidation of this impurity by spectral data ((1)H NMR, (13)C NMR, DEPT, MS and IR), formation and mechanism has been discussed in detail.

Impurity profile study of zaleplon.

Zaleplon is a pyrazolopyrimidine derivative and possesses sedative and hypnotic properties. Seven unknown impurities in zaleplon bulk drug at levels below 0.1% were detected by reverse-phase high performance liquid chromatography (HPLC). The starting material, 3-amino-4-cyanopyrazole and an intermediate, N-[3-[3-(dimethylamino)-1-oxo-2-propenyl]-phenyl]-N-ethylacetamide (DOPEA) were also present in the sample at a level below 0.1%. The molecular weights of impurities were determined by LC-MS analysis. These impurities were isolated from crude samples of zaleplon using reverse-phase preparative HPLC. Based on the spectral data the structures of these impurities were characterized as, N-(3-(3-(4-amino-2H-pyrazolo [3,4-d]pyrimidin-6-yl) pyrazolo[1,5-a] pyrimidin-7-yl)phenyl)-N-ethylacetamide (impurity I); N-[3-(3-carboxamidopyrazolo[1,5-a]pyrimidin-7-yl)phenyl]-N-ethylacetamide (impurity II); N-[3-(3-cyanopyrazolo[1,5-a]pyrimidin-7-yl)phenyl]acetamide (impurity III); N-[3-(3-cyanopyrazolo [1,5-a]pyrimidin-7-yl)phenyl]-N-methylacetamide (impurity IV); N-[3-(3-cyanopyrazolo[1,5-a] pyrimidin-5-yl)phenyl]-N-ethylacetamide (impurity V); N-[3-(3-cyanopyrazolo[1,5-a] pyrimidin-7-yl)phenyl]-N-ethylamine (impurity VI); N-[3-(3-cyano-6-[(E)-3-((N-ethyl-N-acetyl)amino)phenyl-3-oxoprop-1-enyl] pyrazolo[1,5-a]pyrimidin-7-yl) phenyl]-N-ethylacetamide (impurity VII). Structural elucidation of all impurities by spectral data ((1)H NMR, (13)C NMR, MS and IR) and formation of these impurities are discussed in detail.