Effect of boron addition on the microstructure and mechanical properties of 6.5% V-5% W high speed steel

The effect of adding 0.04% additional boron to 6.5% V-5% W high speed steel was investigated. The microstructure characterization, phase identification, and carbide identification of the materials were performed using SEM/EDS and XRD. The cell size and carbide volume fraction were examined using image analysis software. The boron distribution was observed by PTA Boron Tracking. The addition of 0.04% more boron to a HSS alloy exerted a cell refining effect on the sample. The cell refinement of dendritic structures in the alloy containing boron may be attributed to the constitutional supercooling effect associated with the fairly small distribution coefficient for boron in iron. The addition of boron increases the bending strength of the material by more than 10%, as well as increasing its hardness.     

Utilization of electron beam irradiated almond skin powder as a natural antioxidant in ground top round beef

ABSTRACT:  Defatted Carmel variety almond skin powder (ASP) irradiated at 0, 10, 20, and 30 kGy was mixed with ground top round beef at 0.5% (w/w) and stored at 4 °C. Color stability, peroxide values (PV), conjugated dienes (CD), thiobarbituric acid reactive species (TBARS), and hexanal were determined periodically over a 2-wk period. The L values were not affected by time or treatment. Initially, the redness ( a value) was higher for both the negative control with no ASP ( a value of 21.83) and positive control with 0.01% BHT ( a value of 22.33) compared to samples that contained the ASP ( a values from 17.70 to 20.17) on day 1. This decrease in redness was attributed to the presence of the ASP. Similar to day 1, the a values were not significantly different between the 2 controls over the duration of the study. All the samples with ASP exhibited lower lipid oxidation when compared to the negative control, with greatest oxidation retardation observed at 20 and 30 kGy. Over the treatment period, a 13% to 85% reduction in PV and a 40% to 80% reduction in TBARS were observed in the sample with 30 kGy ASP compared to the negative control. Generally, PV and TBARS of samples with ASP decreased with an increase in irradiation dose. While a difference due to irradiation dose was not observed in CD and hexanal content, the values were significantly lower ( P < 0.05) than the controls over time. This study demonstrates that almond skin power could be used to extend the shelf life of refrigerated ground raw beef.     

Comment on “Multiple cycle economic lot and delivery-scheduling problem in a two-echelon supply chain”

This paper revisits the work-in process inventory formulation presented by Torabi and Jenabi which appeared in Int J Adv Manuf Technol (43:785–798, 2009, doi: 10.1007/s00170-008-1752-6).     

Reverse micelle facilitated synthesis of nanostructured polyaniline as the counter electrode materials in dye-sensitized solar cells

ABSTRACT

We report a reverse-micelle emulsion polymerization of nanostructured PANI using a nonionic surfactant Polyglyceryl-2-Dipolyhydroxystearate (PGPH) at various concentrations from 2% to 6% (v/v). SEM images show that the obtained morphologies are irregular agglomerates at low PGPH concentration and relatively regular granules at high PGPH concentration. FTIR and Raman spectra show that the synthesized PANI is in the form of Emeraldine salt (PANI ES) with electrical conductivity around 10^?3 S cm^?1. Photovoltaic current-voltage (J-V) measurements show the highest power conversion efficiency is achieved at 1.71% at 6% (v/v) of PGPH.     

Pore structure alteration of porous carbon by catalytic coke deposition

The feasibility of preparing Carbon Molecular Sieve (CMS) by tailoring pore structure of activated carbon under catalytic cracking of benzene has been examined. In this method, benzene vapour was cracked over metal-impregnated activated carbon particles at 523–773 K. Among the metal catalysts tested, only cobalt exhibited significant cracking activity toward benzene. In this range of temperature coke was originated on the metal surface only, therefore an excessive coke deposition as indicated in non-catalytic process was not observed. The amount of coke and the site of deposition in the pore network were determined to some extent by the metal loading as well as the rate of benzene cracking. Raman spectra indicated that the coke produced was less amorphous than those produced in non-catalytic processes. Only a small loss in micropore volume and surface area was observed after the coke deposition process. The CMS produced was tested for its adsorption characteristics of carbon dioxide and methane. The improvement in the CO₂/CH₄ kinetic selectivity was observed.     

Bioactive albumin functionalized polylactic acid membranes for improved biocompatibility

Biocompatibility is a major challenge for successful application of many biomaterials. In this study the ability to coat chemically and enzymatically activated poly(L-lactic acid) (PLA) membranes with heat denatured human serum albumin to improve biocompatibility was investigated. PLA membranes hydrolyzed with NaOH or cutinase and then treated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, hydrochloride (EDAC) as a heterobifunctional cross-linker promoted the coupling COOH groups on PLA membranes and NH₂ groups of heat denatured human serum albumin. This resulted in increased hydrophilicity (lowest water contact angles of 43° and 35°) and highest antioxidant activity (quenching of 79 μM and 115 μM tetramethylazobisquinone (TMAMQ) for NaOH and cutinase pretreated membranes, respectively). FTIR analysis of modified PLA membranes showed new peaks attributed to human serum albumin (amide bond, NH₂ and side chain stretching) appearing within 3600–3000 cm^?1 and 1700–1500 cm^?1 (Fig. 3). MTT studies also showed that osteoblasts-like and MC-3T3-E1 cells viability increased 2.4 times as compared to untreated PLA membranes. The study therefore shows that this strategy of modifying the surfaces of PLA polymers could significantly improve biocompatibility.     

An inventory model involving back-order price discount when the amount received is uncertain

This paper presents and analyses the continuous review inventory model with order quantity, safety factor, back-order price discount, ordering cost and lead time as decision variables. Our work is based on the paper of Huang (2010 Huang, S.-P. (2010). Using simple and efficient algorithm involving ordering cost reduction and backorder price discount on inventory system under variable lead time. Information Technology Journal, 9(4), 804–810.[Crossref] , [Google Scholar]). We extend the model to incorporate the situation when the amount received is uncertain. The lead time demand is assumed follows a normal distribution. A solution procedure is developed to find the optimal solution. A numerical example is given to illustrate the model. A sensitivity analysis is also included to describe the effects of changes in the model parameters on the expected annual cost.     

Load–displacement behavior of glass fiber/epoxy composite plates with circular cut-outs subjected to compressive load

An experimental study of the behavior of woven glass fiber/epoxy composite laminated panels under compression is presented. Compression tests were performed on to 16 fiber-glass laminated plates with and without circular cut-outs using the compressed machine. The maximum load of failure for each of the glass-fiber/epoxy laminated plates under compression has been determined experimentally. A parametric study was performed as well to investigate the effects of varying the centrally located circular cut-out sizes and fiber angle-ply orientations on to the ultimate load. The experimental work revealed that as the cut-out size increases, the maximum load of the composite plate decreases. Also, it has been observed that cross-ply laminates possess the greatest ultimate load as compared to other types of ply stacking sequences and orientations.     

The effect of structural properties of natural silica precursors in the mesoporogen-free synthesis of hierarchical ZSM-5 below 100 °C

The low-temperature synthesis of zeolite ZSM-5 below 100 °C is gaining new attention. This is due to the fact that such synthesis may simultaneously implement the introduction of mesopores into crystalline microporous zeolite structure. Herein, we report the use of natural silica precursors from rice husks in the mesoporogen-free synthesis of hierarchical ZSM-5 below 100 °C and their structural properties which govern the course of crystallization. Rice husks are agricultural wastes with high silica content, which should be exploited to give a positive impact, i.e. highly value-added materials. In this study, the amorphous silica from rice husks was extracted using sequential base-acid treatment. The extracted silica was similarly reactive as Ludox HS-40, even with the reduced amounts of the organic structure-directing agent (OSDA). The product was highly crystalline ZSM-5 with spherical morphology composed of small crystallites, enabling the presence of intercrystallite mesopores. The subjection of extracted silica into the calcination at 550 °C for 6 h, prior to the low-temperature synthesis, altered the silica structure via hydroxyl condensation. The distinct structural properties affected the occurring crystallization in which the resulted products were ZSM-5–disordered-mesoporous silica composites. The possible mechanisms of these two different results may involve the dual roles of tetrapropylammonium ion (TPA⁺) as zeolite OSDA and non-templating structure directing agent. These insights were based on the spectroscopic (FTIR, Raman, ²⁹Si and ²⁷Al MAS NMR spectroscopy), microscopic (TEM and HRTEM) and physicochemical characterizations (XRD and N₂ adsorption-desorption isotherm).     

Hyperchaos permutation on false-positive-free SVD-based image watermarking

Multimedia Tools and Applications - This paper reports the effect of hyperchaos permutation on the False-Positive-Free (FPF) Singular Value Decomposition (SVD)-based image watermarking scheme. To...