Dissimilar Joining Between Austenitic and Duplex Stainless Steel in Double-Shielded GMAW: A Comparative Study

In the present work, the effect of double-layer shielding and five other process parameters, namely welding voltage, current, primary shielding gas type, its flow rate, and filler material, is studied during dissimilar gas metal arc welding (GMAW) between austenitic and duplex stainless steels (SSs). A simple modification over the GMAW setup is made for additional supply of secondary shielding gas at different flow rates. Two different sets of welding are performed between austenitic and duplex SSs, i.e., AISI 304 with Duplex 2205 and AISI 316 with Duplex 2205, and the contributions of process parameters, their interactions on joint distortion, tensile strength, toughness, and fusion zone microhardness are evaluated. Improvements in joint quality due to the double-shielding environment are also highlighted. Double-layer shielding with secondary shielding by CO₂ supply significantly improves tensile strength and toughness and reduces distortion. Fusion and interface zone microstructures are observed by scanning electron microscopy to study the metallurgical behavior of joints fabricated under single- and double-layer shielding environment.     

A novel attention fusion network-based framework to ensemble the predictions of CNNs for lymph node metastasis detection

Diagnosis of lymph node metastases is a challenging task for pathologists, involving an extensive screening of the pathological scans. Automating diagnostic processes reduces the workload of pathologists and yields high accuracy by the virtue of advances in technology. In this study, a novel ensemble-based framework is proposed for the classification of lymph node metastases. The proposed ensemble framework comprises different pre-trained CNN models such as DenseNet201, InceptionV3 and ResNeXt-50. In the proposed framework, an attention fusion network is utilized to amalgamate the predictions of the individual models. The proposed framework achieves an AUC-ROC of 0.9816 which surpasses the highest AUC-ROC achieved by the conventional approaches on the PCam benchmark dataset.

     

Kinetics and design relation for enzymatic conversion of lactose into galacto-oligosaccharides using commercial grade β-galactosidase

The enzymatic synthesis of galacto-oligosaccharides (GOS) from lactose was studied using commercial grade β-galactosidase (Biolacta FN5) from Bacillus circulans. The reaction was carried out under free enzyme condition varying initial lactose concentration (ILC: 55-525?g/L), enzyme concentration (0.05-1.575?g/L), temperature (30-50°C) and pH (5.0-6.0). Reaction mixture compositions were analyzed utilizing high performance liquid chromatography (HPLC). A?maximum GOS formation of 39% (dry basis) was achieved at an ILC of 525?g/L converting 60% of the lactose fed. Tri-saccharides were the major types of GOS formed, accounting approximately 24%; whereas, tetra-saccharides and penta-saccharides account approximately 12% and 3%, respectively. Design correlation was developed in order to observe the quantitative effect of operating parameters on GOS yield. Further, based on Michaelis-Menten model, four-step reaction pathways were considered for simplistic understanding of the kinetics. Apart from predicting the reaction mixture composition, the approach also provided kinetic parameters though simulation using COPASI 4.7(?). Excellent agreements were observed between simulated and experimental results.     

In vitro study of anti-oxidative effects of β-carotene and α-lipoic acid for nanocapsulated lipids

In this study we attempted to assess the efficacy of the in vitro activities of β-carotene and α-lipoic acid in conjugation with an encapsulated lipid. Nanoemulsion was prepared and freeze-dried to get nanocapsules. Highest encapsulation efficiency 84.32 ± 1.08% was achieved for α-lipoic acid nanocapsules, whereas for β-carotene nanocapsules it was 79.63 ± 1.41%. Morphology study showed that the dried capsules had an irregular, rough surface. Both anti-oxidants were equally effective in releasing core materials. Complete release of the total lipid occurred within 210 min from both β-carotene and α-lipoic acid bearing nanocapsules. Stability study revealed that β-carotene nanocapsules showed decrease in oil content from 79.63 g lipid to 72.8 g lipid for every 100 g lipid encapsulated, in 3 months, whereas α-lipoic acid nanocapsules retained oil much better, the oil retention being from 84.32 g lipid to 78.08 g lipid per 100 g lipid encapsulated. DPPH radical scavenging activity of β-carotene and α-lipoic acid ranged from 62.75% and 44.13% to 32.94% and 36.95% (after 90 days) respectively. Reducing activity of β-carotene was higher (absorbance 0.492 to 0.291 at 90 days) compared to α-lipoic acid (absorbance 0.243 to 0.109 after 90 days). Again β-carotene and α-lipoic acid metal-chelation activity ranged from 47.65% and 48.59% to 32.315% and 39.29% after 90 days.     

Compaction agglomeration of corn starch in presence of different binders

A model powder system comprising corn starch has been subjected to compaction agglomeration in presence of different binders like sugar (0-20%), pre-gelatinised starch (PGS) powder (0-20%) and vegetable oil (0-5%). The compacted masses are examined for density and different textural parameters (linear limit of deformation and modulus of deformability, and failure properties like failure stress/energy/strain) employing uniaxial compression.An increase in sugar and PGS markedly increases the failure stress, energy for failure and modulus of deformability while showing a reverse trend for oil added samples. The strain at failure increases with the addition of PGS and oil (6.9-14.5 and 6.9-24.4%, respectively) whereas marginal effect (6.9-8.1%) occurs with sugar. Compacted mass having 20% PGS behaves as the toughest sample. Cluster analysis among the textural parameters indicates a high similarity of 85% between failure stress and energy for failure. A mechanism of failure has been proposed for compacted mass during compression that has been supported by microstructures.     

Galactosyl oligosaccharide purification by ethanol precipitation

Galactosyl oligosaccharides (GOS) are prebiotics commonly manufactured by β-galactosidase conversion of lactose, producing a mixture containing GOS, lactose, glucose and galactose. Enrichment of GOS in this mixture adds value to the product. This study aimed to determine whether the addition of ethanol to aqueous saccharide solutions could be used to selectively precipitate and enrich GOS from a reaction mixture. High concentrations of ethanol (>70% v/v) were required to induce precipitation. The total saccharide concentration was a significant variable, with higher GOS enrichment occurring at lower total saccharide concentrations. Varying the temperature between 10 and 40 °C had less impact than had changes in the concentration of saccharide or ethanol. GOS was enriched 2.3 (±0.1) fold in the precipitate formed in a solution of 90% (v/v) ethanol with 28 g/L of total saccharide at 40 °C. Performing two such precipitations sequentially reduced the monosaccharides from 48% (w/w) of the total saccharides to 4% (w/w). GOS precipitation has potential for industrial application as it is simple in operation and offers levels of purification similar to those by other techniques.     

Dimethyl ether synthesis from Victorian brown coal through gasification – Current status,and research and development needs

Victorian brown coal, one of the largest and cheapest energy sources in the world, is currently used in mine-mouth coal-fired power plants. These power plants have low efficiency and high CO₂ emission. Alternative process paths leading to electricity generation and chemical production can provide more energy efficient and environment friendly applications of brown coal. Synthesis of dimethyl ether (DME) from brown coal is an attractive option because of its environmentally benign properties and wide range of applications. This article first reviews the current and likely future applications of brown coal. In the latter part of the article emphasis has been given on DME, since it stands out as a suitable option from both environmental and economic point of view. Finally research needs for the development and commercialisation of DME production process from brown coal has been identified.     

Effect of bovine serum albumin on the functionality and structure of catanionic surfactant at air–buffer interface

Interaction of bovine serum albumin (BSA) with the solvent spread monolayer of a catanionic surfactant, octadecyltrimethylammonium dodecylsulfate, (C₁₈TA⁺DS^?) at the air–buffer interface was investigated by measuring the surface pressure with time and change in surface area. Dipalmitoylphosphatidylcholine (DPPC) was used as reference. Kinetics of BSA desorption from the interface to the buffer subphase, that of C₁₈TA⁺DS^? and DPPC through their interaction with BSA, were also studied at different BSA concentrations (in the subphase) and surface pressures. Surface pressure (π)–area (A) isotherms (at pH = 5.4, μ = 0.01, T = 298 K) revealed that the coacervate/DPPC monolayer becomes expanded in the presence of BSA at low π while their protein bound species are released into the subphase at high π. Film morphology, studied by epifluorescence microscopy (EFM) and atomic force microscopy (AFM), reveals that the sizes of the domains of both DPPC and coacervate decrease in the presence of BSA. Presence of BSA in the coacervate and DPPC monolayer was supported from AFM data analysis.     

Optimal parameter settings for rough and finish machining of die steels in powder-mixed EDM

The present study was undertaken to identify the appropriate parameter settings for rough and finish machined surface for EN31, H11, and high carbon high chromium (HCHCr) die steel materials in a powder-mixed electric discharge machining process. The effect of seven different process variables along with some of their interactions was evaluated using a dummy-treated experimental design and analysis of variance. Material removal rate (MRR), tool wear rate, and surface finish were measured after each trial and analyzed. The parameter settings for rough and finished machining operations were obtained. EN31 exhibited maximum MRR as compared to the other two materials at similar process settings. Copper (Cu) electrode with aluminum suspended in the dielectric maximized the MRR. Suspending powder in the dielectric resulted in surface modification. Graphite powder showed a lower MRR but improved the surface finish. HCHCr require higher current and pulse on settings for initiating a machining cut and works best in combination with tungsten–Cu electrode and graphite powder for improved finish. The MRR for H11 is lower than EN31 but significantly higher than HCHCr under same process conditions.