Preparation of poly(styrene‐co‐butyl acrylate)/montmorillonite nanocomposite by emulsion polymerization: Characterization and nanoscratch behavior

Organic–inorganic hybrid poly(styrene‐co‐butyl acrylate)/organically modified montmorillonite (PSBA/organo‐MMT) latex particles have been prepared by in situ emulsion polymerization. The effects of modifier variety and the level of organo‐MMT have been investigated on the basis of the characteristics and mechanical properties of the resulting hybrid emulsion polymers. Although the more hydrophilic intercalated organic modifiers increased the latex particle size, the hydrophobic ones decreased the particle size. A more heterogeneous copolymer chain intercalation was seen by widespread XRD reflection as the organo‐MMT (organoclay) level increases. The tapping mode atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to determine the dispersion state of organoclay particles inside the nanocomposite copolymer films. Dynamic mechanical thermal analysis (DMTA) showed that adding the organoclay to the copolymer decreased the maximum loss tangent (tanδ) value and caused the shift to a lower temperature. Interestingly, the incorporation of organoclay decreased the glass storage modulus of the copolymer, while increased the rubbery storage modulus to some extent. In addition, a standard indenter for the nanoscratching of copolymer nanocomposite films was used under low applied loads of 150 and 250 μN. The nanoscratch results showed that incorporation of a 3 wt % hydrophobic organoclay, e.g., Closite15A, in the copolymer matrix enhanced considerably the near‐surface hardness and grooving resistance of the nanocomposite film at room temperature. In fact, copolymer nanocomposite films with higher near‐surface hardness and tanδ curve broadening exhibited more nanoscratch resistance through a specific variety of viscoelastic deformation, which did not create a bigger groove. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Machining stability in high speed drilling—Part 2: Time domain simulation of a bending–torsional model and experimental validations

In this paper, the torsional limits of stability in drilling are first obtained analytically based on Bayly's work [P.V. Bayly, S.A. Metzler, A.J. Schaut, K.A. Young, Theory of torsional chatter in twist drills: model, stability analysis and composition to test, Journal of Manufacturing Science and Engineering, 123 (2001) 552–561]. Subsequently, a time domain simulation model of chatter in drilling is presented. The novel simulation model, developed in this work, combines the effects of both bending and torsion. The major challenge in this model is the tracking of the instantaneous cutting parameters along the lips while vibrating in both modes. This challenge was met here successfully and the simulation results agreed closely with the analytical solutions. Cutting experiments were also conducted to verify the developed chatter models. Two drills, one “short” and one “long” were used in drilling a large number of holes with different pilot-hole diameters. The agreement between the cutting tests and theoretical predictions was not very close for the “short” drill due to inaccuracies in representing the boundary conditions in the mathematical model. On the other hand, the cuttings tests agreed very closely with the analytical and numerical predictions for the “long” drill.     

Syntheses of Fe-TiC nanocomposite from ilmenite concentrate via microwave heating

In this paper, the possibility of production of Fe-TiC nanocomposite as a useful ceramic, from ilmenite concentrate, aluminum powder and carbon black has been investigated. Different amounts of FeTiO₃, carbon black and Al powder were activated by a high-energy ball mill. Then the mixtures were synthesized by microwave heating at various times. The results of XRD investigation indicated that TiC has been synthesized within 5–10 min treatment microwave time. Moreover, it was found that by increasing the aluminum content, the Fe₂O₃ phase was replaced by SiC and Al₂O₃. In addition, from the broadening of the diffraction lines in the XRD patterns analysis, it was concluded that the TiC crystallites are nano-sized. Also, it was found that the existence of Al lead to increased grain size and decrease of the strain in the process.     

Effect of Salvia officinalis L. extract on chemical,microbial, sensory and shelf life of rainbow trout fillet

Food Science and Biotechnology - The present study aimed at extending shelf life of rainbow trout fillet. Fish and seafoods are the most valuable nutrients, however, high levels of moisture, free...     

Chemical and microbiological stability and sensorial properties of traditional Iranian butter incorporated with pomegranate peel extract

In this study, the antioxidant activity of pomegranate peel extract (PPE) and its potential effect on the chemical and microbiological stability of traditional butter was investigated. The PPE having total phenol content of 327.48 ± 1.43 mg gallic acid equivalent/g showed significantly greater (64.34 ± 0.32%) radical scavenging activity than butylated hydroxy toluene. Butter treated with PPE had significantly lower levels of peroxide value, free fatty acids, Totox, Schaal value and microbial population. The work concluded that PPE could be an excellent natural source of antimicrobial and antioxidant substances, which can be used for traditional butter preservation.     

Theoretical modification of the finely porous model for reverse osmosis transport

One of the most significant models used to describe and predict the performance of reverse osmosis type membranes is the finely porous model (FPM). In this paper, the basic assumptions of the model are examined and modified. The two most serious problems with FPM are that an incorrect form of material balance on the solute is used and that the osmotic pressure effects are not completely taken into account for electrolytes. A modified model (called MD-FPM), which is based on the same physical precepts is derived. Equations describing the concentration profile for both models have been derived and compared. It has been shown that the FPM can predict physically unacceptable results. Difficulties in using the parameters from the model for prediction or for membrane development work are discussed. Simulation results for the MD-FPM model are consistent with what is expected for reverse osmosis type membranes.     

Integrated Structural–Architectural Design for Interactive Planning

Traditionally, building floor plans are designed by architects with their usability, functionality and architectural aesthetics in mind; however, the structural properties of the distribution of load‐bearing walls and columns are usually not taken into account at this stage. In this paper, we propose a novel approach for the design of architectural floor plans by integrating structural layout analysis directly into the planning process. In order to achieve this, we introduce a planning tool which interactively enforces checks for structural stability of the current design, and which on demand proposes how to stabilize it if necessary. Technically, our solution contains an interactive architectural modelling framework as well as a constrained optimization module where both are based on respective architectural rules. Using our tool, an architect can predict already in a very early planning stage whose designs are structurally sound such that later changes due to stability reasons can be prevented. We compare manually computed solutions with optimal results of our proposed automated design process in order to show how much our proposed system can help architects to improve the process of laying out structural models optimally.     

Adhesion of tin droplets impinging on a stainless steel plate: effect of substrate temperature and roughness

We photographed impact of small tin droplets on stainless steel surfaces of varying temperature and roughness. To achieve high impact velocities the test surfaces were mounted on the rim of a rotating fly wheel. Substrate temperature (T_s) was varied from 120 to 220 °C and surface roughness (R_a) kept at either 0.05 or 2 µm. We kept constant the impact velocity (30 m/s) and droplet diameter (0.6 mm). To form a coating 60 droplets were deposited randomly on each stainless steel test coupon. Deposition efficiency was evaluated by dividing the mass adhering to the coupon by the mass of sixty droplets prior to impact. The maximum deposition efficiency was achieved at a substrate temperature of 160 °C. For T_s < 160 °C the deposition efficiency was higher on a rough surface (R_a = 2 µm) than on a smooth surface (R_a = 0.05 µm), since splats did not adhere well to the smooth surface. For T_s≥ 160 °C the deposition efficiency was higher on a smooth surface (R_a = 0.05 µm) than on a rough surface (R_a = 2 µm), since splats splashed less on the smooth surface.

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