Fabrication and characterisation of silver nanoparticles using bract extract of Musa paradisiaca for its synergistic combating effect on phytopathogens,free radical scavenging activity,and catalytic efficiency

This work explores the rapid synthesis of silver nanoparticles (AgNPs) from Musa paradisiaca (M. paradisiaca) bract extract. The bio‐reduction of Ag⁺ ion was recorded using ultraviolet–visible spectroscopy by a surface plasmon resonance extinction peak with an absorbance at 420 nm. The phytoconstituents responsible for the reduction of AgNPs was probed using Fourier transform infrared spectroscopy. The X‐ray diffraction pattern confirmed the formation of crystalline AgNPs that were analogous to selected area electron diffraction patterns. Morphological studies showed that the obtained AgNPs were monodispersed with an average size of 15 nm. The biologically synthesised AgNPs showed higher obstruction against tested phytopathogens. The synthesised AgNPs exhibited higher inhibitory zone against fungal pathogen Alternaria alternata and bacterial pathogen Pseudomonas syringae. Free radical scavenging potential of AgNPs was investigated using 1,1‐diphenyl‐2‐picryl hydroxyl and 2,2‐azinobis (3‐ethylbenzothiazoline)‐6‐sulphonic acid assays which revealed that the synthesised AgNPs act as a potent radical scavenger. The catalytic efficiency of the synthesised AgNPs was investigated for azo dyes, methyl orange (MO), methylene blue (MB) and reduction of o‐nitrophenol to o‐aminophenol. The results portrayed that AgNPs act as an effective nanocatalyst to degrade MO to hydrazine derivatives, MB to leucomethylene blue, and o‐nitro phenol to o‐amino phenolInspec keywords: catalysis, dyes, electron diffraction, nanofabrication, silver, catalysts, surface plasmon resonance, reduction (chemical), free radicals, nanoparticles, transmission electron microscopy, nanobiotechnology, X‐ray diffraction, microorganisms, organic compounds, Fourier transform spectra, nanomedicine, visible spectra, antibacterial activity, infrared spectra, ultraviolet spectraOther keywords: silver nanoparticles, musa paradisiaca, synergistic combating effect, free radical scavenging activity, catalytic efficiency, M. paradisiaca, bio‐reduction, ultraviolet–visible spectroscopy, surface plasmon resonance extinction peak, Fourier transform infrared spectroscopy, X‐ray diffraction pattern, selected area electron diffraction patterns, radical scavenging potential, potent radical scavenger, size 420.0 nm, size 15.0 nm, Ag⁺      

Impact of air intrusion on the wind uplift performance of fully bonded roofing assemblies

Wind performance investigation is critical in the design of durable roofing assemblies. In North America, mainly two types of low slope roofs, conventional and inverted, are in practice depending on the placement of the membrane in the assembly. As part of the conventional low-sloped roofs, in a fully bonded assembly (FBA) the insulation is mechanically attached and waterproof membrane is bonded to the insulation using adhesives. Recent field investigations of roof failures after major hurricanes indicated that FBA are susceptible to high wind events. To understand the response of the FBA under dynamic environment, an extensive experimental study has been carried out by the SIGDERS – Special Interest Group for Dynamic Evaluation of Roofing Systems, at the National Research Council. The present study focuses on the impact of air intrusion on wind uplift performance of these assemblies. Airflow control is usually achieved by including a barrier/retarder in the roofing assembly. Assembly with barrier improved the wind uplift rating by two fold when compared to an assembly without barrier. Use of staggered insulation arrangement can provide similar air retarding effect as a barrier and can therefore sustain similar wind uplift pressures compared to an assembly with barrier.     

Influence of Vegetable Oils on Micellization of Lutein in a Simulated Digestion Model

Lutein and zeaxanthin are selectively accumulated in the macula of the retina, yet their bioavailability is influenced by various dietary factors. Insights regarding the effects of dietary lipids on lutein micellization that is available for absorption are limited. This study investigated the influence of vegetable oils on the relative efficiency of lutein micellization using in vitro digestion procedure. Lutein dispersed in either olive oil (OO), corn oil (CO), soybean oil (SBO), sunflower oil (SFO), groundnut oil (GNO), rice bran oil (RBO) or palm oil (PO) was subjected to simulated gastric and small intestinal digestion. Results showed that the efficiency of micellization of lutein dispersed in olive oil exceeds the other vegetable oils. The percent lutein micellization was in the order of OO > GNO > RBO > SFO > CO > SBO > PO. In comparison, the values for OO were higher than GNO (11%), RBO (18.3%), SFO (19%), CO (21.7%), SBO (30.5%) and PO (35.2%), respectively. These results suggest that OO rich in oleic acid may favor the incorporation of lutein into micelles at the intestinal level. To conclude, the type of vegetable oil in which carotenoids are dispersed is important to achieve an enhanced bioavailable lutein. The correlation between the micellizable lutein and fatty acid composition of vegetable oils are discussed.     

Unsaturated polyester nanocomposites filled with nano alumina

Alumina nanoparticles (60–70 nm) were prepared by the sol–gel technique using citric acid and aluminum nitrate. Casting technique was used to make nanocomposites of unsaturated polyester (UPR) and nano alumina. Transmission Electron Microscopy (TEM) study demonstrated that nano alumina particles were dispersed uniformly in the UPR matrix and agglomeration of particles was found at higher filler loading (>5 wt%). The nanocomposites show higher tensile, flexural and impact strength than pristine UPR. Scanning Electron Microscopy (SEM) of the fractured surface of tensile test samples show that the ductile fracture of UPR was converted to brittle fracture with the addition of nano alumina. Dynamic Mechanical Analysis (DMA) studies showed the storage modulus increased up to 5 wt% loading of nano alumina. The impact strength and storage modulus results agree well. The thermogravimetric studies revealed that the nanocomposites were having higher thermal stability than the pure UPR. As the concentration of the nano alumina in the UP resin increased, the char yield was also increased.     

Anthropogenic and natural radionuclides in caribou and muskoxen in the western Alaskan Arctic and marine fish in the Aleutian Islands in the first half of 2000s

A number of caribou and muskoxen samples from the western Alaskan Arctic and fish samples from the Aleutian Islands were collected between 1998 and 2006 and analyzed for anthropogenic (⁹⁰Sr and ¹³⁷Cs) and natural radionculides (⁴⁰ K, ²¹⁰Pb and ²²⁶Ra), as part of the radiological assessment for the regional subsistence hunting communities in the first half of 2000s. We examined the relationship between the activities of these nuclides with the size of the fish. In caribou samples, concentration of ⁹⁰Sr in muscle was below the detection limit of 0.14 Bq kg^− 1 and ¹³⁷Cs concentration in bones was below the detection limit of 0.15 Bq kg^− 1.¹³⁷Cs activity varied over an order of magnitude in caribou muscle samples with an average value of 2.5 Bq/kg wet wt. Average ¹³⁷Cs activity in muskoxen muscle was found to be 9.7 Bq/kg wet wt. However, there were a little variation (less than 60%) in ²¹⁰Pb, ⁴⁰ K, and ²²⁶Ra in both muscle and bone of both caribou and muskoxen. The activities of total ²¹⁰Pb in caribou and muskox bones were found to be 1-2 orders of magnitude higher than that of parent-supported ²¹⁰Pb indicating the potential for dating of bones of terrestrial mammals (time elapsed since the death of the animal) based on the excess ²¹⁰Pb method exists. In fish muscle samples, ¹³⁷Cs activity varied from below detection limit to 154 mBq/kg wet wt. and its content increased with the size of the fish due to its transfer through the food chain. Among the seven fish species investigated, ²¹⁰Pb activities varied almost an order of magnitude; however, ⁴⁰K and ²²⁶Ra activities varied less than a factor of two. Total annual effective dose due to ⁹⁰Sr and ¹³⁷Cs from the ingestion of those terrestrial and marine meats was estimated to be negligible (ca. 9 μSV/a) compared to the natural radionuclides present thus posing negligible radiological threat to humans.     

A novel magnetic random access memory design using square ring elements for the hard layer

The behavior of narrow permalloy square rings under the influence of a magnetic field was studied using magnetic force microscopy (MFM). Two stable states of opposite polarity at remanence and simple switching were observed. We propose a design for the hard layer of magnetic random access memory (MRAM) that uses these states in square rings for data storage.     

Fibrous Monolithic Ceramics: IV, Mechanical Properties and Oxidation Behavior of the Alumina/Nickel Systein

Fibrous monolithic ceramics were fabricated in the alumina/nickel system. The microstructure consists of high-aspect-ratio polycrystalline cells of alumina separated by thin cell boundaries of nickel. The nickel content in the material is 3 to 8 vol%. The fibrous monolith with uniaxially aligned cells fails noncatastrophically in flexure. Bridging ligaments of nickel, crack deflection along cell boundaries, and crack branching in the axial direction are observed in flexure bars and notched beams. Strength values range from 246 to 375 MPa. Indentations cause controlled damage on the surface but do not introduce strength-degrading flaws. The alumina/nickel fibrous monoliths also show potential for use at high temperatures in oxidizing environments. Noncatastrophic fracture behavior is observed at room temperature after 10 h at 1200°C in air. The Ni cell boundary network is oxidized to a depth of 50 to 100 μm by this heat treatment. The NiO oxidation product in the cell boundaries reacts partly with alumina from the cells to form NiAI₂O₄, which would provide better protection.     

Study on vital static properties of fine blanking of GFRP composites with that of conventional drilling

Among the high performance engineering materials, fiber-reinforced plastics play an important role. The present work is concerned with the comparison of vital static strength properties of fine blanking with conventional drilling on hand lay-up made glass fiber-reinforced plastic (GFRP) laminates of four different reinforcement lay-up sequences such as unidirectional [0/0]_n, angle ply [0?±?45]_ns, quasi-isotropic [0/45/90]_ns, and cross-ply [0/90]_n. Observation includes tensile and flexural bending strengths of the specimens without hole and with hole by conventional drilling and fine blanking. In this work, an endeavor has been made to simulate the service conditions to determine their effect on the response of composite laminates. Detailed studies on GFRP composites when subjected to different loading environments such as static loading, particularly tensile loading, and low frequency high amplitude (fatigue) loading were carried out. The response of the composite laminates to these service environments has been evaluated in terms of flexural strength and modulus. From the tensile study, it was observed that by inserting a hole at center by drilling, the strength was reduced to one third, and by inserting a hole at center by fine blanking, the strength was increased nearly 20% than that of drilling. Apart from this, the flexural test conducted on polymeric composite specimens showed that an exposure to low frequency and high amplitude loading enhances the flexural strength up to certain duration of exposure, beyond which, due to accumulation of damage within the composites, the flexural strength reduces with number of cycles. This can be attributed to possible strain-induced stiffening of fibers and interface.     

A novel approach to estimate the wind uplift resistance of roofing systems

Roof wind design consist of three parts: determination of wind loads, evaluation of wind uplift resistance and correlating the resistance with the design load such that the resistance is higher than the load requirement. Wind uplift resistance of a system with its respective components is evaluated in laboratory testing. This paper presents a novel approach to estimate wind uplift resistance when components are substituted during field application. Wind dynamics, on a mechanically attached single-ply roofing assembly, lift the membrane and cause fluttering, introducing stresses at the attachment locations. In such assemblies, the fastener–deck interface is a critical design factor. First, by taking steel deck as a component this paper systematically characterizes the various steel decks that are commonly used in low slope application. Second component, namely the fasteners and its engagement strength with deck have been quantified for variations of its design, size and sources. Based on this component characterization, fastener pullout resistance (FPR) is identified as a verification factor for system wind resistance estimation. When variations occur in the fastener–deck interface between the proposed and the existing configurations, the present research through case studies has proved that: “as long as the FPR of the proposed configuration is higher than the existing configuration then wind uplift ratings can be maintained”. This is valid as long as both the configurations have all the remaining roofing components similar with comparable layout. Based on this verification, the study recommends that the testing lab should report the FPR along with the wind uplift resistance such that FPR can be used as a verification factor to accept design/field alternatives.     

Invisible emotion magnification algorithm (IEMA) for real-time micro-expression recognition with graph-based features

Multimedia Tools and Applications - The interest in real-time micro-expression recognition has increased with the current trend in human-computer interaction applications. Presently, there are...