Instrumental texture and flavonoid profile of paste developed from sprouted onion varieties of Indian origin

The effect of sprouting on the instrumental texture, antioxidant activity, and ?avonoid pro?le of the paste prepared from four Indian onion varieties (Punjab White, Punjab Naroya, PRO-6, and Commercial) was studied. The significant (P ? 0.05) effect of sprouting on microstructure, firmness, adhesiveness, gumminess, and chewiness in paste samples from all varieties was observed. There was significant decrease (P ? 0.05) in lightness with consequent significant (P ? 0.05) increase in redness, greenness, and yellowness in paste samples which was due to the increase in anthocyanin content with sprouting. The paste samples from sprouted onion varieties also showed an increase in phenol content, flavonoid content, antioxidant capacity, and DPPH radical scavenging activity. The HPLC analysis revealed an increase in total flavonoids in pastes from PRO-6 and Punjab Naroya varieties. Thus, present study implied that sprouting could be beneficial as it enhanced the functional potential of onion pastes.     

Investigating the value of integrated operations planning: A case-based approach from automotive industry

During the last decade, many researchers have focused on joint consideration of various operations planning aspects like production scheduling, maintenance scheduling, inventory control, etc. Such joint considerations are becoming increasingly important from the point of view of current advancement in intelligent manufacturing, also known as Industry 4.0. Under the concept of Industry 4.0, advanced data analytics aim to remove human intervention in decision-making. Thus, the managerial level coordination of decisions taken independently by various departments will be out of trend. Therefore, developing an approach that optimises various operations planning decisions simultaneously is essential. Available literature on such joint considerations is more of the exploratory in nature and is limited to simplistic production environments. This necessitates the investigations of value of integrated operations planning for wide range of manufacturing scenarios. Present paper adopts a case-oriented approach to investigate the value of integrated operations planning. First, an integrated approach for simultaneously determining job sequencing, batch-sizing, inventory levels and preventive maintenance schedule is developed. The approach is tested in a complex production environment of an automotive plant and substantial economic improvement was realised. Second, a comprehensive evaluation is performed to study the robustness and implications of proposed approach for various production scenarios. Results of such pervasive performance investigations confirm the value of proposed approach over conventional approaches.     

Dynamic Fracture of a Zr-based Bulk Metallic Glass

In the present study, dynamic fracture experiments are performed on fully amorphous Liquidmetal-1 (LM-1), a Zr-based BMG, to better understand fracture initiation and propagation in notched specimens. Experiments are conducted on notched (110 μm notch radius) four-point bend specimens using an instrumented modified split-Hopkinson pressure bar apparatus. The results of these experiments suggest that the critical dynamic stress intensity factor achieved by the notched LM-1 specimens is ~110 MPa m^1/2, which is similar to the fracture toughness determined from previous quasi-static fracture experiments. This insensitivity of the fracture toughness to crack tip loading rate suggests negligible loading-rate sensitivity on the dynamic fracture initiation toughness in LM-1. In situ high-speed camera images of the notched sample during the dynamic loading process show multiple fracture initiation attempts and subsequent arrests prior to catastrophic fracture initiation. Controlled stress wave loading experiments designed to induce sub-critical levels of damage in the notched specimens show extensive deformation banding extending 150 to 200 μm outward from the notch. The deformation bands, nominally perpendicular to each other, run along the direction of the notch and perpendicular to it. They are consistent with slip-line fields in notched samples of elastic perfectly plastic materials. Subsequent loading of the damaged specimen again shows several attempts at crack initiation followed by blunting; the initial sub-critical damage in the region around the notch is understood to increase the energy required for catastrophic specimen failure and is consistent with an increase in the effective notch radius due to preexisting damage.     

A study on electromagnetic property during friction stir weld failure

Electromagnetic radiation is emitted during the transient stage of elastic to plastic deformation of metals and alloys. In the present work, aluminium plates were welded by friction stir welding (FSW) at different process parameters, such as tool rotational speed, traverse speed and rake angle. The EMR fundamental frequencies emitted during the tensile failure of the welds were measured and recorded. The variation in the fundamental frequency was analysed by fuzzy modelling using MATLAB and it was observed that an increase in the first mode of metal transfer decreases the fundamental frequency. Further, the fundamental frequency of a weld was estimated from the obtained model and found to be closer to the experimental results. This work will be more useful for metal flow analysis as well as online condition monitoring of the welds which are used in critical applications.     

Swelling Deswelling Behavior of PS‐PNIPAAM Copolymer Particles and PNIPAAM Brushes Grafted from Polystyrene Particles & Monoliths

Two sets of emulsion particles have been synthesized. In the first set, surfactant free emulsion was used to directly synthesize PS‐PNIPAAM copolymer particles. In the second set, polystyrene particles with an ATRP initiator shell were first synthesized and subsequently grafted with PNIPAAM brushes. Swelling/deswelling behavior of both sets of particles was studied with respect to temperature and time. Monoliths with two different porosities were also formed by grafting and crosslinking of PNIPAAM chains on the aggregated particles and characterized. In all cases, swelling kinetics is sufficiently fast to use these supports for separation driven by temperature changes only. However, hindrance and cross‐linking is sensibly reducing the material performance.

     

A novel nano-configuration for thermoelectrics: helicity induced thermal conductivity reduction in nanowires

In this article, we propose a novel helical nano-configuration towards the designing of high ZT thermoelectric materials. Non-equilibrium molecular dynamics (NEMD) simulations for 'model' bi-component nanowires indicate that a significant reduction in thermal conductivity, similar to that of flat superlattice nanostructures, can be achieved using a helical geometric configuration. The reduction is attributed to a plethora of transmissive and reflective phonon scattering events resulting from the steady alteration of phonon propagating direction that emerges from the continuous rotation of the helical interface. We also show that increasing the relative mass ratio of the two components lowers the phonon energy transmission at the interface due to differences in vibrational frequency spectra, thereby relatively 'easing' the phonon energy propagation along the helical pathway. While the proposed mechanisms result in a reduced lattice thermal conductivity, the continuous nature of the bi-component nanowire would not be expected to significantly reduce its electrical counterpart, as often occurs in superlattice/alloy nanostructures. Hence, we postulate that the helical configuration of atomic arrangement provides an attractive and general framework for improved thermoelectric material assemblies independent of the specific chemical composition.     

Nanocomposite Hydrogel Materials for Defective Cartilage Repair and Its Mechanical Tribological Behavior—A Review

Osteoarthritis (OA) is a regressive ailment that affects a large population of patients. The most common symptoms of OA in humans are cartilage abnormalities. Hydrogels are excellent candidates for cartilage regeneration and are widely accepted as implants. In the past few decades, numerous types of hydrogels have been synthesized to repair cartilage defects. This study highlights recent advances in hydrogel development for the treatment of cartilage defects. In addition, the detailed progression of tailored nanocomposite hydrogels is summarized, and emphasis has been placed on the mechanical properties, especially the tribological behavior of the developed nanocomposite hydrogels.     

Identification of stiffness and damping characteristics of axial air-foil bearings

Air-foil bearings (AFBs) are self acting hydrodynamic bearings made from sheet metal foils comprised of at least two layers. The innermost “top foil” layer traps a gas pressure film that supports a load while the layer or layers underneath provide an elastic foundation. AFBs are currently used in many commercial applications, both terrestrial and in aerospace. AFBs provide a means to eliminate the oil system leading to reduce weight and enhanced temperature capability. Regardless of the application of the AFBs, the identification of the structural characteristics is important for successful design practice. In the present work, structural characteristics (stiffness and damping) of axial AFBs are indentified in the light of experimental results. Due to the initial high torque requirement of the AFB, the experimental setup using a single AFB is proposed instead of standard two-foil bearing setups. Experiments are carried out at maximum speed of 60,000 rpm. Sub-structuring approach is used for identification of the structural (stiffness and damping) characteristics of the AFB. The results have shown that the developed experimental procedure is able to identify the stiffness and damping characteristics of axial AFBs accurately.     

Steam drum level dynamics in a multiple loop natural circulation system of a pressure-tube type boiling water reactor

Advanced Heavy Water Reactor (AHWR) is a pressure tube type boiling water reactor employing natural circulation as the mode of heat removal under all the operating conditions. Main heat transport system (MHTS) of AHWR is essentially a multi-loop natural circulation system with all the loops connected to each other. Each loop of MHTS has a steam drum that provides for gravity based steam–water separation. Steam drum level is a very critical parameter especially in multi-loop natural circulation systems as large departures from the set point may lead to ineffective separation of steam–water or may affect the driving head. However, such a system is susceptible to steam drum level anomalies under postulated asymmetrical operating conditions among the different quadrants of the core like feedwater flow distribution anomaly among the steam drums or power anomaly among the core quadrants. Analyses were carried out to probe such scenarios and unravel the underlying dynamics of steam drum level using system code RELAP5/Mod3.2. In addition, a scheme to obviate such problem in a passive manner without dependence on level controller was examined. It was concluded that steam drums need to be connected in the liquid as well as steam space to make the system tolerant to asymmetrical operating conditions.     

Limonene encapsulation in freeze-drying of gum Arabic-sucrose-gelatin systems

Encapsulation of limonene in freeze-drying of various matrices consisting of gum Arabic, sucrose and gelatin was studied. Retention of limonene in freeze-drying was observed by measuring absorbance at 252 nm using a spectrophotometer. Two different levels of limonene, in the weight ratios (w/w) of 9:1 and 8.5:1.5 (total solids (TS):limonene) were studied. Highest amount of limonene (75.3±0.3% of initially added amount) in the emulsions homogenised at 25 MPa (4 MPa in second stage) followed by freeze-drying, was retained in a matrix consisting of gum Arabic, in the ratio of 9:1 (w/w). A mixture consisting of gelatin-sucrose-gum Arabic in the w/w ratio of 0.66:0.17:0.17 retained highest amount (71.8±0.1% of initially added amount) of limonene in the ratio (w/w) of 8.5:1.5 (TS:limonene). A matrix consisting of gum Arabic-sucrose-gelatin (1:1:1 w/w/w) with added limonene at a ratio (w/w) of 9:1 (TS:limonene), was used to study the effects of ultra high-pressure homogenisation (50-250 MPa) on limonene encapsulation in freeze-drying. Highest amount (84% of initially added amount) of limonene was retained in the emulsions homogenised at a pressure of 100 MPa. Electron micrograph of freeze-dried matrix of gum Arabic-sucrose-gelatin in the weight ratio of 1:1:1 suggested that it possessed a flake like structure, which was free of dents and shrinkage. A mixture consisting of gum Arabic-sucrose-gelatin is an efficient encapsulant for limonene encapsulation by freeze-drying.