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Accumulative roll bonding (ARB) is a severe plastic deformation technique commonly applied to produce ultrafine grain materials. ARB has evolved as a promising method in the last decade to produce aluminum matrix composites (AMCs) effectively, overcoming the common issues faced in various casting methods. This review summarizes the research works accomplished in producing AMCs using ARB and critically discusses the literature on each aspect. Homogenous distribution of reinforcement particles in the composite is exceptionally achieved in this process. The factors affecting the distribution, the breakage of particles and the grain size are critically reviewed and elucidated. The interfacial details and porosity issues are addressed. The difficulty in processing nano- and multiple particles to produce AMCs is explained. ARB provides high-strength composites. The underlying strengthening mechanisms for significant improvement in tensile, wear and corrosion properties are explained. ARB is recently applied as a secondary processing tool to improve the distribution and properties of cast AMCs. This aspect of ARB is further covered. The review concludes with applications, future development of this process and extensions to produce other metallic composites. [ABSTRACT FROM AUTHOR]

Introduction: Lumbar degenerative spondylolisthesis with resultant stenosis is a common condition typically seen at L4-L5, in females more commonly than males, and in individuals older than 50 years of age. The slippage is generally due to degenerative changes in the zygapophyseal joints between the 2 vertebrae with accompanying degeneration of the disc at that level. Objectives: To evaluate the clinical outcome of surgically treated patients and also to evaluate the radiological outcome of surgically treated patients. Methodology: The study was conducted in Metropolitan Hospital, Thrissur, Kerala between August 2006 and January 2008 including 16 patients who were treated surgically for degenerative Spondylolisthesis. Results:The age distribution pattern in our study shows that 75% of the patients are less than 55 Years. The average age of patients is 51 years with standard deviation of 10.41. The male to female ratio of patients undergoing surgical treatment for degenerative spondylolisthesis in our study is 1:3. The radiological outcome of fused, partially fused and not fused categories were found in the ratio of 1:2:1. 8 patients have post-operative ODI between 11-20 of which 4 are in fused and 4 in partially fused category. Out of 3 patients with post-operative ODI ≤10, 2 are partially fused and 1 is not fused. Conclusion: Good clinical results can be obtained by augmenting the decompression and fusion procedure with instrumentation. [ABSTRACT FROM AUTHOR]

Incremental Sheet metal Forming (ISF) Process is a suitable process which helps to produce various parts used in automotive sector by rapid prototyping. This method of producing a prototype helps industry in reducing the production cost. In ISF process, a final product is evolved through local deformation of the sheet metal made by the tool. Usually better formability is obtained when the tool makes a better contact with the sheet metal throughout the process. Improved formability elevates dimensional accuracy of the product, thus increases the market value of the product. A new tool with multiple ball ends capable of making multiple mating points over sheet metal was used in this research to enhance the efficiency of formability and surface finish. Ability of the new Multi-Point Incremental Forming Tool (MPIF) was investigated and compared to the existing Single Point Forming Tool (SPIF) based on the formability and surface finish. Forming Limit Diagram (FLD), Strain Distribution (SD) and Scanning Electron Microscope (SEM) were used to examine the formability of the sheet metal. The SEM & 3D-Surface roughness profilometer were used to observe the sheet metals surface finish. In addition to these experimental techniques a simulation results were also used to predict the stress and strain rate during forming process. The experimentation and simulation outcome shows that the MPIF provides superior formability and surface finish. [ABSTRACT FROM AUTHOR]

We study the fusion of a proton with a nucleus with the emission of two photons at low incident energy of the order of eV or smaller. We use a step model for the repulsive potential between the proton and the nuclei. We consider the reaction both in free space and inside a medium. We make a simple model for the medium by assuming a hard wall potential beyond a certain length scale. This essentially leads to discretisation of the energy spectrum which is expected inside a medium and is seen both for a crystalline lattice structure and for amorphous materials. We use second-order perturbation theory to compute the transition rate. We find that the rate in free space is very small. However, in the medium, the rate may be substantial. Hence, we conclude that nuclear fusion reactions may take place at low energies at observable rates. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the existence of mild solutions and optimal controls for a class of fractional neutral stochastic integrodifferential equations driven by Rosenblatt process and Poisson jumps in Hilbert spaces. First we establish a new set of sufficient conditions for the existence of mild solutions of the aforementioned fractional systems by using the successive approximation approach. The results are formulated and proved by using the fractional calculus, solution operator and stochastic analysis techniques. The existence of optimal control pairs of system governed by fractional neutral stochastic differential equations driven by Rosenblatt process and poisson jumps is also been presented. An example is provided to illustrate the theory. [ABSTRACT FROM AUTHOR]

Mixed pixels in aerial and satellite images are common, especially near the boundaries of two or more discrete classes; that is, they tend to occur at the transitional region between two classes. Ideally, to decipher the mixed pixel, a soft classification is performed compared to a hard- or a per-pixel classification. Soft or subpixel classification is carried out where the fractional cover of the LULC contained within a pixel is derived. Endmembers are extracted for three VNIR bands of ASTER data for two image datasets using three approaches, namely, principal component analysis (PCA), pixel purity index (PPI), and convex hull-Graham scan (CHGS). On comparing the DN values of the identified endmembers, it is observed that the CHGS method provides the most appropriate end members than the PCA-derived and PPI-derived end members. This is based on deriving the endmembers from two different image conditions. Convex hull implemented using the Graham scan algorithm delineates the pure pixel and pinpoints the exact number of endmembers. These accurate end members would result in accurate proportions of the land cover for better modeling of the terrain. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated the efficacy of deep learning architectures in enhancing the interpretation of skin images, thereby aiding in the classification and segmentation of skin cancer. However, the existing deep learning techniques predominantly focus on either segmentation or classification and are designed for normally distributed data. Addressing this limitation, the present study introduces a hybrid ensemble deep learning approach for skin cancer classification and segmentation. This proposed model amalgamates Residual Learning Machines, Swin Transformers, and Fast Neural Networks (FNN) to proficiently manage diverse sets of non-uniformly distributed data, thereby augmenting diagnostic accuracy. The efficacy of this approach was evaluated using various skin cancer datasets, including ISIC-2008, PH-2, and HM007. The assessment involved several performance metrics, such as the Matthew correlation coefficient (MCC), recall, F1-score, specificity, accuracy, and precision. Moreover, to underscore the superiority of the proposed model, its performance was juxtaposed with that of previous efforts. Results from repeated trials indicate that the proposed model achieved 98.78% classification accuracy, 98.7% precision, 98.7% F1-score, 98.64% average recall, and an MCC of 0.9863 across different skin disease datasets. Demonstrating consistent superiority over existing methods, the proposed approach shows considerable potential in revolutionizing the diagnostics of skin cancer. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated the efficacy of deep learning architectures in enhancing the interpretation of skin images, thereby aiding in the classification and segmentation of skin cancer. However, the existing deep learning techniques predominantly focus on either segmentation or classification and are designed for normally distributed data. Addressing this limitation, the present study introduces a hybrid ensemble deep learning approach for skin cancer classification and segmentation. This proposed model amalgamates Residual Learning Machines, Swin Transformers, and Fast Neural Networks (FNN) to proficiently manage diverse sets of non-uniformly distributed data, thereby augmenting diagnostic accuracy. The efficacy of this approach was evaluated using various skin cancer datasets, including ISIC-2008, PH-2, and HM007. The assessment involved several performance metrics, such as the Matthew correlation coefficient (MCC), recall, F1-score, specificity, accuracy, and precision. Moreover, to underscore the superiority of the proposed model, its performance was juxtaposed with that of previous efforts. Results from repeated trials indicate that the proposed model achieved 98.78% classification accuracy, 98.7% precision, 98.7% F1-score, 98.64% average recall, and an MCC of 0.9863 across different skin disease datasets. Demonstrating consistent superiority over existing methods, the proposed approach shows considerable potential in revolutionizing the diagnostics of skin cancer. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the existence, uniqueness and stability of mild solutions of time-dependent impulsive neutral stochastic partial integro differential equations with fractional Brownian motion and Poisson jumps. The existence of mild solutions for the equations are discussed by means of semigroup theory and theory of resolvent operator. Next, certain sufficient conditions and results are obtained by using the method of successive approximation and Bihari's inequality. Finally, an example is provided to illustrate our results. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the existence of mild solutions and optimal controls for a class of fractional neutral stochastic differential equations (NSDEs) driven by fractional Brownian motion and Poisson jumps in Hilbert spaces. First, we establish a new set of sufficient conditions for the existence of mild solutions of the aforementioned fractional systems by using the successive approximation approach. The results are formulated and proved by using the fractional calculus, solution operator, and stochastic analysis techniques. The existence of optimal control pairs of system governed by fractional NSDEs driven by fractional Brownian motion and Poisson jumps is also been presented. An example is provided to illustrate the theory. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the approximate controllability for time-dependent impulsive neutral stochastic partial integrodifferential equations with Poisson jumps in Hilbert space. The results are obtained by using theory of resolvent operator and fixed point approach, we derive a new set of sufficient conditions for the approximate controllability of nonlinear stochastic system under the assumption that the corresponding linear system is approximately controllable. Finally, an example is provided to illustrate our results. [ABSTRACT FROM AUTHOR]

Hot cracking free fusion welds of re-sulphurized, high machinable grade stainless steel AISI 416 were obtained while adopting Laser-arc Hybrid Welding (LAHW) with the use of Ni-Cr-Mo rich austenitic filler metal. The carbon enriched martensite was observed at the interface of weld region, which, in turn, contributed for an elevated hardness. Both gamma ray non-destructive testing and cross-sectional analysis further affirm the absence of porosity and solidification cracking in the weld region of AISI 416. Mechanical integrity of the joints were established using tension and Charpy V-notch impact tests. Notch tensile studies revealed that the joint strength was much higher compared to the base metal. A slight delineation in notch impact toughness of the LAHW joints is ascribed to the formation of sulphide inclusions. The outcomes of the study recommend the use of the LAHW for joining difficult-to-weld metals. [ABSTRACT FROM AUTHOR]

The fusion zone microstructure and mechanical properties of UNS S32750 joints obtained from gas tungsten arc (GTA), gas metal arc (GMA) and flux cored arc (FCA) welding processes were investigated. The formation of grain boundary, Widmanstätten and intragranular austenite were observed in the fusion zone of the weldments. Electron back scattered diffraction (EBSD) analysis confirmed the presence of chi (ψ) and sigma (σ) phases in the reheated fusion zones of all the weldments. Tensile failures occurred at the fusion zone for all the weldments and the joint efficiency was found to be greater for GTA welds than the others. The number of welding passes and heat input had a significant impact on the ferrite: austenite ratio. FCA weldments experienced inferior notch toughness at both room temperature and sub-zero temperature owing to the prominent amount of secondary austenite and precipitation of intermetallic phases compared to the other weldments. [ABSTRACT FROM AUTHOR]

The microstructure traits and structural integrity of Ti-6Al-4 V welds of 5 mm thickness are discussed. The use of activated flux in the tungsten inert gas (ATIG) welding technique is adopted in this study using the oxide surfactant. Bead on trials attested that the depth of penetration (DOP) is enhanced with a corresponding rise in welding current upon the use of oxide surfactant. Microstructure studies depicted the presence of acicular α’ structure of martensitic needles and Widmanstätten α platelets with β-Ti grain boundaries throughout the fusion zone. Tensile studies indicated that the strength of the joints of ATIG welds was better, as the failures were experienced in the parent metal. The impact toughness of the ATIG weldments was insignificantly reduced when compared to the base metal owing to the coarsened grains in the weld zone. The findings of this study attests the use of low cost welding technique for joining Ti-6Al-4 V of 5 mm thickness for improved properties. [ABSTRACT FROM AUTHOR]

Single point incremental forming process is a most economical Die-less forming process. The major constraint of it is that it is a time consuming process. In this work, a new attempt was made in incremental forming process using Multipoint tool for SS430 sheets to increase the formability and to reduce forming time. Fractography analysis was made to study the size of voids that were formed during fracture. The forming limit diagrams were drawn and compared for single point incremental forming and the multipoint incremental forming of SS430 sheet. It was proved that the formability of SS430 sheet in the multipoint forming was better than the formability of that in single point forming and the time consumed was reduced. The strain distribution in both processes had also been studied along with surface roughness. [ABSTRACT FROM AUTHOR]

Details a study which measured the capacitance-voltage of grain boundaries made on cast polycrystalline silicon wafers. Description of the experimental grain boundary capacitance-voltage curves; Calculation of capacitance-voltage curves; Results and discussion.

Describes the voltage-current characteristics of tin-oxide-silicon interfaces prepared by spray pyrolysis. Theoretical model for the explanation of the observed characteristics at low currents; Overview of the proposed carrier transport mechanism; Formula for resistance drop.

Focuses on a study that reported the variations in impedance with frequency of metal-oxide-semiconductor structures on polycrystalline silicon. Methods; Discussion; Conclusion.

Presents a study which examined particulate composites consisting of barium titanate, graphite and rubber. Mechanism proposed to explain positive voltage coefficient of resistance; Model for the composite; Estimation of resistivity; Use of composites as varistors.

This study addressed the use of activated flux SiO for the gas tungsten arc (GTA) welding of super-austenitic stainless steel plates of 5 mm thickness. Trials were carried out to investigate the effect of flux and the welding current to determine the depth of penetration. Bead-on-plate trials were carried out on the AISI 904L with and without flux. It was inferred from the macrostructure studies that with a welding current of 180 A, complete penetration could be achieved using flux-assisted GTA welding. The optimal process parameters were validated by conducting the experimental investigations to ascertain the structure-property relationships of flux-assisted GTA weldment. Experimental results corroborated that the average tensile strength and impact toughness of SiO flux-assisted GTA weldments of AISI 904L were observed as 553 MPa and 49.3 J. It was inferred from the studies that defect-free welds of super-austenitic stainless steel could be obtained on employing flux-assisted GTA welding process. [ABSTRACT FROM AUTHOR]

The present study addresses the effect of fillers on the microstructure and tensile strength of dissimilar joints of Inconel 625 and UNS S32205 by pulsed current gas tungsten arc welding (PCGTAW) employing ERNiCrMo-10 and ERNiCrMo-14 fillers. This study attested that tensile failure occurred in the fusion zone of the dissimilar joints for both the cases in the as-welded un-peened condition. Double shot laser shock peening (DLSP) was performed on the fusion zone of these PCGTA welds on the cap and root regions of the weldments. It was assimilated that after DLSP on the cap and root regions of the weldments, the yield and tensile strength of the welded joints employing these fillers were improved considerably. Residual stress analysis were carried out on the dissimilar coupons using X-ray Diffraction analysis. The results demonstrated that after subjecting to double sided DLSP, the fusion zones were subjected to compressive residual stresses. The present study articulated that shot peening using low energy laser beam resulted in better tensile strength. [ABSTRACT FROM AUTHOR]

Presents a study that assessed the voltage-current characteristics in the breakdown region of p-n junctions made on polycrystalline silicon of large grain size. Information on the voltage-current characteristics of a large number of monosilicon and polysilicon diodes; Examination of the field-dependent emission of carriers from traps in the grain boundaries; Analysis of the electric field in the curved junction.

Focuses on the origin of the observed negative-resistance characteristics of polycrystalline silicon resistors. Effects of self-heating of the resistor on the transportation of carriers across the grain-boundary barrier; Equation of the potential barrier at the grain boundary; Description of the structure of the polycrystalline silicon resistor.

This study addresses the effect of post weld heat treatment on the fusion zone microstructure and the mechanical properties of activated flux tungsten inert gas (A-TIG) weldments of Inconel X750. In this study, a compound flux of 50% SiO 2 +50% MoO 3 was used for A-TIG welding of the samples. Comparative studies on the microstructure and mechanical properties have been made on the weldments both in the as-welded and post weld heat treated conditions. Direct ageing post weld heat treatment (PWHT) was carried out at 705 °C for 22 h on the A-TIG weldment to assess the structure–property relationships. It was inferred that direct ageing post weld heat treatment resulted in better tensile strength (1142 MPa) compared to the as-welded coupons (736 MPa). The joint efficiencies of the as-welded and post weld heat treated conditions were found to be 60.7% and 94.07% respectively. The impact toughness of the as-welded coupons were found to be greater than the post weld heat treated samples; however the impact toughness of the welds are greater than the parent metal employed in both the cases. This study also attested the detailed structure–property relationships of A-TIG weldments using the combined techniques of optical and scanning electron microscopy, Electron Dispersive X-ray Analysis (EDAX) techniques. [ABSTRACT FROM AUTHOR]

This research work articulates the microstructural features of the dissimilar weldments involving Ni based superalloy Inconel 718 and martensitic stainless steel, AISI 416 that is difficult to weld. Autogenous tungsten inert gas (TIG) welding was carried out with and without using flux to fabricate these bimetallic combinations. Microstructure at the fusion zones and the interfaces were characterized using optical and scanning electron microscopy. The results depicted the presence of fine martensite at the heat affected zone (HAZ) of AISI 416 and the formation of unmixed zone containing secondary phases at the HAZ of Inconel 718. Similarly, the formation of Nb rich eutectics along with sulfides was witnessed at the fusion zone of both the weldments. Owing to the low heat input witnessed during the flux assisted TIG welding, the Nb segregation was found to be minimal. Tensile studies reported that the fracture occurred at the fusion zone in both the cases. It was inferred from the tensile studies that the joint strength of the weldments with flux addition was greater than the ones without flux. This study demonstrated that dissimilar joints with complete penetration could be achieved in single pass using the TIG welding process with the aid of flux. [ABSTRACT FROM AUTHOR]

The present research work involves the study of AA 7075-TiB2-Gr in situ composite through stir casting route. This in situ method involves formation of reinforcements within the matrix by the chemical reaction of two or more compounds which also produces some changes in the matrix material within the vicinity. Titanium Diboride (TiB2) and graphite were the reinforcement in a matrix of AA 7075 alloy. The composite was prepared with the formation of the reinforcement inside the molten matrix by adding salts of Potassium Tetrafluoroborate (KBF4) and Potassium Hexafluorotitanate (K2TiF6). The samples were taken under casted condition and the properties of the composite were tested by conducting characterization using X-ray diffraction (XRD), hardness test, flexural strength by using three-point bend test, scanning electron microscope (SEM), optical microstructure, grain size analysis, and surface roughness. It was found that good/excellent mechanical properties were obtained in AA 7075-TiB2-Gr reinforced in situ hybrid composite compared to alloy due to particulate strengthening of ceramic particles of TiB2 in the matrix. Further, Al 7075-3% TiB2-1% Gr hybrid in situ composite exhibited improved machinability over the alloy and composites due to self-lubricating property given by the Gr particles in the materials. [ABSTRACT FROM AUTHOR]

This paper addresses the weldability, microstructure and mechanical properties of the multi-pass welding of super-duplex stainless steel (SDSS). Pulsed current gas tungsten arc welding (PCGTAW) was carried out employing ER2553 and ERNiCrMo-4 fillers. Microstructure examination showed the presence of austenite in different forms at the weld zone of ER2553 whereas multi-directional grain growth was observed for ERNiCrMo-4 welds. Tensile and impact studies corroborated that the weldments employing ER2553 exhibited better results compared with ERNiCrMo-4 weldments. Detailed structure-property relationships of the weldments have been reported in the present study. The results corroborated that the enhanced properties could be achieved with the matching filler wire compared with the over-alloyed filler. [ABSTRACT FROM AUTHOR]

This research article addresses the joining of 5 mm thick plates of Inconel 718 by activated flux tungsten inert gas (A-TIG) welding process using SiO 2 and TiO 2 fluxes. Microstructure studies inferred the presence of Nb rich eutectics and/or laves phase in the fusion zone of the A-TIG weldments. Tensile studies corroborated that the ultimate tensile strength of TiO 2 flux assisted weldments (885 MPa) was better compared to SiO 2 flux assisted weldments (815 MPa) and the failure was observed in the parent metal for both the cases. Impact test results portrayed that both the weldments were inferior in toughness as compared to the parent metal, which was due to the presence of oxide inclusions. Also, the study investigated the structure–property relationships of the A-TIG weldments of Inconel 718. [ABSTRACT FROM AUTHOR]

This research work articulated the effect of SiO 2 flux assisted tungsten inert gas (TIG) welding on the microstructure and mechanical properties of marine grade stainless steel weldments, such as super-duplex stainless steel (UNS S32750) and austenitic stainless steel (AISI 316L). The studies showed that the use of flux decreased the heat input required to obtain complete penetration. Microstructure studies revealed the presence of ferrite at the heat affected zone of AISI 316L and the fusion zone which obviated the hot cracking tendency. Tensile studies corroborated that the joint strength was sufficiently greater than that of the parent metals. Impact toughness slightly impoverished owing to the presence of large platelets of Widmanstätten austenite in the fusion zone. The study also explored the structure–property relationships of the flux assisted weldments using the combined techniques of optical and scanning electron microscopy analysis. Owing to the better metallurgical and mechanical properties, this study recommends the use of SiO 2 flux for joining the dissimilar metals involving austenitic and super-duplex stainless steels. [ABSTRACT FROM AUTHOR]

This study addresses the comparison of metallurgical and mechanical properties of autogeneous and activated compound flux assisted gas tungsten arc welding (GTAW) of super-austenitic stainless steel, AISI 904L. The use of compound flux containing 85% SiO 2 –15% TiO 2 acquainted for better depth of penetration compared to autogeneous welding. Segregation of Mo rich phases was witnessed in the fusion zone of flux assisted AISI 904L. Tensile studies showed that the fracture occurred at the fusion zone for both the weldments. Ductility was found to be greater for the flux-assisted weldments. The present study also investigates the structure–property relationships of AISI 904L weldments using the combined techniques of optical and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

The metallurgical and mechanical properties of electron beam welded Ni based superalloy Inconel 625 and UNS S32205 duplex stainless steel plates have been investigated in the present study. Interface microstructure studies divulged the absence of any grain coarsening effects or the formation of any secondary phases at the heat affected zone (HAZ) of the electron beam (EB) weldments. Tensile studies showed that the fracture occurred at the weld zone in all the trials and the average weld strength was reported to be 850 MPa. Segregation of Mo rich phases was witnessed at the inter-dendritic arms of the fusion zone. The study recommended the use of EB welding for joining these dissimilar metals by providing detailed structure – property relationships. [ABSTRACT FROM AUTHOR]

This article investigated the weldability, metallurgical and mechanical properties of Inconel 625 and AISI 316L stainless steel weldments obtained by continuous current (CC) and pulsed current (PC) gas tungsten arc welding (GTAW) processes employing ERNiCr-3 and ER2209 fillers. Microstructure studies showed the migrated grain boundaries at the weld zone of ERNiCr-3 weldments and multi-directional grain growth for ER2209 weldments. It was inferred from the tension tests that the fracture occurred at the parent metal of AISI 316L in all the cases. Charpy V-notch impact tests accentuated that the CCGTA weldments employing ERNiCr-3 filler offered better impact toughness of 77 J at room temperature. Further a detailed study has been carried out to analyze the structure - property relationships of these weldments using the combined techniques of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. [ABSTRACT FROM AUTHOR]

In the present investigation, an attempt has been made to weld the precipitation hardened Nickel based super alloy Inconel 718 and austenitic stainless steel AISI 316L using Continuous Current Gas Tungsten Arc Welding (CCGTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) process employing ER2553 and ERNiCu-7 fillers. Microstructure examination using optical and SEM analysis clearly witnessed the formation of unmixed zone at the Heat Affected Zone (HAZ) of Inconel 718 for all the joints. The studies showed the absence of deleterious phases in the CCGTA and PCGTA weldments employing ERNiCu-7. Tensile studies corroborated that the fracture occurred at the parent metal of AISI 316L in all the cases. It was inferred from the present study that PCGTA weldments employing ERNiCu-7 exhibited better metallurgical and mechanical properties. This study articulated the effect of filler metals on the structure-property relationships of the weldments. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effect of filler metals on the weldability of super-duplex stainless steel plates. [•] Contemplative explanations on the metallurgical and mechanical properties of the weldments. [•] Enhanced mechanical properties of the welds at ambient room temperature. [ABSTRACT FROM AUTHOR]

Objectives Gymnema montanum Hook, an Indian Ayurvedic medicinal plant, is used traditionally to treat a variety of ailments. Here, we report anti-cancer effects and molecular mechanisms of ethanolic extract of G. montanum ( GLEt) on human leukaemia HL-60 cells, compared to peripheral blood mononuclear cells. Materials and methods HL-60 cells were treated with different concentrations of GLEt (10-50 μg/ml) and cytotoxicity was assessed by MTT assay. Levels of lipid peroxidation, antioxidants, mitochondrial membrane potential and caspase-3 were measured. Further, apoptosis was studied using annexin-V staining and the cell cycle was analyzed by flow cytometry. Results GLEt had a potent cytotoxic effect on HL-60 cells ( IC50-20 μg/ml), yet was not toxic to normal peripheral blood mononuclear cells. Exposure of HL-60 cells to GLEt led to elevated levels of malonaldehyde formation, but to reduced glutathione, superoxide dismutase, catalase and glutathione peroxidase activities ( P < 0.05). Induction of apoptosis was confirmed by observing annexin-V positive cells, associated with loss of mitochondrial membrane potential. Cell cycle arrest at G0/G1 was observed in GLEt-treated HL-60 cells, indicating its potential at inducing their apoptosis. Conclusions Findings of the present study suggest that G. montanum induced apoptosis in the human leukaemic cancer cells, mediated by collapse of mitochondrial membrane potential, generation of reactive oxygen species and depletion of intracellular antioxidant potential. [ABSTRACT FROM AUTHOR]

Abstract: Dissimilar metal welding involving AISI 304 and Monel 400 finds widespread use in marine and offshore environments for the fabrication of heat exchangers, evaporators, piping and vessels in petrochemical and power generation industries. However studies on the performance of such weldments are scantly found in the literature even though the individual metals have higher corrosion resistance and strength. This paper reports the work carried out on welding of AISI 304 and Monel 400 using Gas Tungsten Arc Welding (GTAW) technique to examine the weldability, mechanical and metallurgical properties. Investigations have been carried out on the hot corrosion behavior of these joints subjected to cyclic air oxidation and K2SO4 +NaCl (60%) molten salt environment at 600°C. A comparative analysis was carried out on these weldments for two different filler metals such as E309L and ENiCu-7. The oxide scales formed on the various zones of the weldment have been characterized systematically using surface analytical techniques. Weld zone was found to be more susceptible to degradation than base metals used. The effect of filler materials on the hot corrosion is discussed. The studies reported in this paper would be beneficial for fabricators embracing this type of dissimilar weldments in the petrochemical and power generation industries. [Copyright &y& Elsevier]

The mammalian prefrontal cortex (PFC) has been implicated in a variety of motivational and emotional processes underlying working memory, attention and decision making. The PFC receives dopaminergic projections from the ventral tegmental area (VTA) and contains high density of D1 and D2 receptors and these projections are important in higher integrative cortical functions. The neurons of the PFC have been shown to undergo atrophy in response to stress. In an earlier study, we demonstrated that the chronic stress-induced atrophy of hippocampal neurons and behavioral impairment in the T-maze task were reversed by the activation of dopaminergic pathway by intracranial self-stimulation (ICSS) of the VTA. The stress-induced decrease in hippocampal dopamine (DA) levels was also restored by ICSS. Whether the reversal of stress-induced behavioral deficits by ICSS involves changes in the morphology of PFC neurons is unknown and the current study addresses this issue. Male Wistar rats underwent 21 days of restraint stress followed by ICSS for 10 days. The dendritic morphology of the PFC neurons was studied in Golgi-impregnated sections. Stress produced atrophy of the layer II/III and V PFC pyramidal neurons and ICSS to naïve rats significantly increased the dendritic arborization of these neurons compared to control. Interestingly, ICSS of stressed rats resulted in the reversal of the dendritic atrophy. Further, these structural changes were associated with a restored tissue levels of DA, norepinephrine and serotonin in the PFC. These results indicate that the behavioral restoration in stressed rats could involve changes in the plasticity of the PFC neurons and these results further our understanding of the role of dopaminergic neurotransmitter system in the amelioration of stress-induced deficits. [ABSTRACT FROM AUTHOR]

Abstract: The local (plate)/global (beam) vibration and damping behavior of composite thin-walled box member subjected to vibratory environment are studied and presented in this paper. This investigation is carried out by the use of 3D beam and thin plate finite elements and the corresponding modal frequencies/damping values of composite box beam are predicted by modal strain energy method. Application examples illustrate the ability of the 3D beam and thin plate element to predict both local and global modal frequencies/damping of hollow box sections. The influence of L/h ratio, b/h ratio and ply angle on the frequency and loss factor of composite box beam is investigated. In addition, an attempt has also been made to investigate the effect of temperature on the composite damping characteristics of rectangular box type section. [Copyright &y& Elsevier]

Abstract: In this paper, vibration and damping of composite sandwich box column containing viscoelastic layer (VEL) or electrorheological fluid (ER) core with constraining layer and their performance comparison is carried out. The finite element based modal strain energy method is used for predicting the modal loss factor and frequency of laminated composite box columns with integral viscoelastic/ER fluid layers. Effects of core thickness, orientation of the fiber in the base plate and constraining layer, applied voltage and stacking sequence on the vibration behavior of composite sandwich box column for clamped-free boundary condition are studied in the paper. The performance comparison of vicsoelastic layer damping and ER layer damping is also investigated. [Copyright &y& Elsevier]

• The article is focused on improving the performance of data transmission in wireless sensor network. The highlights of the research are as follows. • Active relay nodes are identified with fuzzy logic and utility factor. • Coverage distance is measured with Received Signal Strength (RSS) • The fuzzy inference system selects the next relay node according to the coverage distance, energy and utility factor and bandwidth availability factors. • By choosing relay node according to the above mentioned factors, the data transmission performance is improved. Numerous sensor nodes are getting utilized in the field of Wireless Sensor Network (WSN) for complex communication. In the recent scenario, there is a lack in the number of sensor node placement with less sensing and communication capabilities. There is less involvement with the characteristics of sensor nodes for direct communication with remote nodes. During the communication, sensor data are communicated to the sink with the help of sensor hubs. Therefore to improve the performance of QoS, routing in the integration of relay node selection plays an important role in WSN. In this paper, we propose Fuzzy based Relay Node Selection and Energy Efficient Routing (FRNSEER) make the routing more efficient by selecting the effective relay node while communicating with the sink node. For selecting the sink node, fuzzy rules are used where active relay nodes are selected as the outcome. The active relay node selection helps to determine the better energy and utility factor during the transmission process. To make better communication between the relay node and the sink node, sensor hubs are used with a lower energy expenditure schedule with expected functions of neighbor/working nodes. In the performance analysis, the proposed mechanism will perform better in terms of packet rate with low energy consumption compared to the existing algorithms such as Fuzzy-based Hyper Round Policy (FHRP) and Neural Network-based Localisation Scheme (NNBLS). [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: This article attempts to relate ultrasonic second harmonic generation to dislocation structures in fatigued materials. By focusing on the fact that asymmetric dislocation motion is required to generate the second harmonic, a theoretical derivation of the non-linearity parameter (ratio of the amplitude of second harmonic to square of the amplitude of the fundamental) from dislocation pile-ups is presented. In order to verify the theory, harmonic generation was measured along a failed fatigue sample of DA718, a nickel base superalloy that exhibits planar slip, and consequently dislocation pile-ups. TEM studies along the length of the failed fatigue sample revealed a banded dislocation structure, composed of pile-ups near the fracture zone and a sparse dislocation network closer to the grip region. The non-linearity parameter was found to increase by between 90% and 140% from the grip region to the fracture zone and this correlated well with the calculations based on theoretical expressions derived here. [Copyright &y& Elsevier]

Much work has been carried out in the general area of hot deformation and more specifically in the understanding and descriptions of the flow response that is observed under conditions that characterise hot deformation. Yet, the issue of the effects of energy dissipated on the metallurgical changes has not been found to be resolved successfully. The systems modelling approach of the dynamic materials model (DMM) has been extended to a study of the stress–strain curve. Definition of a parameter called the energy storage ratio (ESR) enables tracking of the metallurgical processes that underlie the stress–strain curve. It is established that the onset of dynamic recrystallisation corresponds to a constant critical value of the ESR which is independent of strain rate and temperature. [Copyright &y& Elsevier]

The goal of this study is to derive a class of random impulsive fractional stochastic differential equations with finite delay that are of Caputo-type. Through certain constraints, the existence of the mild solution of the aforementioned system are acquired by Kransnoselskii's fixed point theorem. Furthermore, through Ito isometry and Gronwall's inequality, the Hyers-Ulam stability of the reckoned system is evaluated using Lipschitz condition. [ABSTRACT FROM AUTHOR]