Response of a “Plastic hinge” to low-cycle alternating deflections

The paper describes an experimental technique for obtaining the response of a “plastic hinge” to low-cycle alternating loads in which a deflection (strain) range is prescribed. The cycle of loading is confined to equal amplitudes of positive and negative curvature. This response is expressed in terms of a nonlinear moment-curvature relationship which may subsequently be employed in “pseudo-static” structural analysis to derive the load-deflection characteristics of elastic-plastic beams at various stages of cyclic history. A brief account is presented of a fatigue machine designed and constructed for testing mild steel at low endurance levels. A fixture for pure bending is designed to adapt the machine for testing beams and also to provide a measuring system for the applied alternating moments. A meter to measure the curvature in this environment is also described in detail. Similar fixtures are also described for testing cantilever-beam specimens. Moment-curvature models are generated for beams under terminal alternating moments in which ambient strain conditions are controlled. Paper was presented at 1967 SESA Annual Meeting held in Chicago on October 31–November 3.     

Synthesis,thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

A series of poly(benzylidene‐ether)esters containing a photoreactive benzylidene chromophore in the main chain were synthesized from 2,6‐bis(4‐hydroxy‐3‐methoxybenzylidene)cyclohexanone (BHMBCH) with various aliphatic and aromatic diacid chlorides by an interfacial polycondensation technique. The intrinsic viscosity of the synthesized homo and copolymers determined by Ubbelohde viscometer was found to be 0.12 to 0.17 dL/g. The molecular structure of the monomer and polymers was confirmed by FT‐IR, ¹H NMR, and ¹³C NMR spectral analyses. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the polymers were stable up to 280 °C and start degrading thereafter. Increase in acid methylene spacer length decreased the thermal stability. The self‐extinguishing property of the synthesized polymers was studied by calculating the limiting oxygen index (LOI) value using a Van Krevelen's equation. The influence of the length of methylene spacer on phase transition was investigated using DSC and odd‐even effect has been observed. Hot‐stage optical polarizing microscopic (HOPM) study showed that most of the polymers exhibited birefringence and opalescence properties. The photolysis of liquid crystalline poly(benzylidene‐ether)esters revealed that α,β‐unsaturated ketone moiety in the main chain dimerises through 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Whole body vibration analysis for drivers of suspended cabin tractor semitrailer

Experimental Techniques - This work has been conducted to find out the health risk associated with driving suspended cabin tractor semitrailer. Suspended cabin tractor semitrailer drivers are...     

Sorption of Sb(III) on carbon steel surface in presence of molybdate and selenite in citric acid medium

Sorption of Sb(III) on carbon steel surface in aqueous medium (pH 2.8) in presence of different oxyanions like molybdate and selenite has been studied. It is observed that the presence of molybdate or selenite in solution reduced Sb(III) adsorption and surface precipitation to a great extent. The solution at different stages of the adsorption experiment has been analyzed by inductively coupled plasma-atomic emission spectroscopy technique. X-ray diffraction and X-ray photoelectron spectroscopy (XPS) techniques have been used to characterize the precipitate layer and the adsorbed layer. A detailed analysis of the XPS data reveals the mechanism involved in the two cases.     

Crystal structure of 8-(3,4-dimethylphenoxy)-16H dinaphtho[2,1-d:1′,2′-g] dioxaphosphocin 8-oxide

The title compound, C₂₉H₂₃O₄P crystallizes in the triclinic space group witha=9.636(1),b=10.327(1),c=13.406(1) Å, =102.22(1), =100.59(1), =109.84(1)^o.V=1178.1(2) ų,Z=2,D _cal=1.32 M gm^–3, (CuK)=6.16 cm^–1, (CuK)=1.5418 Å andT=295K. The structure was solved by direct methods and refined by full-matrix least-squares method to a finalR=0.052 andwR=0.063 for 2708 reflections withl3(l). The napthalene ring A lies perpendicular to the best plane of the phenyl ring [91.6(1)^o] and the ring B orients at an angle of 55.7(1)^o with this plane and is inclined at an angle of 77.8(1)^o with ring A. The heterocyclic phosphorous eight-membered ring assumes a distorted boat conformation.DCB Contribution No. 822.     

An approach towards the oxidation of 2-amino-4H-chromenes to 2-imino-2H-chromenes

A novel method for the synthesis of 2-imino-2H-benzo[h]chromenes via the sequential addition of N-chlorosuccinimide and triethylamine to 2-amino-4H-benzo[h]chromenes has been established. This reaction protocol represents an efficient synthetic strategy to form iminochromene derivatives under mild reaction conditions, which utilizes readily accessible aminochromenes as starting materials and tolerates a wide range of substrates.     

Biogenic synthesis from <Emphasis Type="Italic">Prunus</Emphasis> × <Emphasis Type="Italic">yedoensis</Emphasis> leaf extract,characterization, and photocatalytic and antibacterial activity of TiO<Subscript>2</Subscript> nanoparticles

Green synthesis of TiO₂ nanoparticles (NPs) from Prunus × yedoensis leaf extract (PYLE), and their application for removal of phosphate and their antibacterial activity, were studied for the first time. NPs were obtained using a green chemistry approach from 0.1 M TiO₂ and PYLE at ratio of 1:1 (v/w). Initial confirmation of production of TiO₂ NPs was provided by a color change from white to light yellow, then calcination was performed at 500 °C for 1 h. The TiO₂ NPs were characterized using various analytical techniques such as ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The results indicated that the optimal amount of TiO₂ NPs for removal of phosphate was 10 mg/l (10 ppm) with duration of 25 min. Furthermore, the antibacterial activity of TiO₂ NPs was also investigated using two different bacteria (Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli) in aqueous medium. The results revealed highly efficient sunlight-driven photocatalytic and antibacterial activity of TiO₂ NPs.     

Quantitation of treatment volumes from CT and MRI in high-grade gliomas: implications for radiotherapy.

Long-term survival of patients with high-grade gliomas remains extremely poor. The main reason for such an outcome is local failure, or recurrence, after surgery and/or radiotherapy. Higher doses of radiation may result in decreased local failure rates provided that the location (and extent) of gross tumor and microscopic disease can be defined accurately. The abnormalities appearing in images from diagnostic modalities, such as CT and MRI, are being used as a starting point and as a guide for the clinical definition of tumor and its extensions. However, some recent studies on two-dimensional specimens, correlating histopathological findings to CT and MRI images, showed that the resulting definition of tumor cell extensions was unsatisfactory, different, and in need of ample margins. We carried out a retrospective analysis to compare the target volumes that would have been defined by CT, T2-weighted MRI, and T1-weighted postgadolinium MRI images of the same individual and to explore the implications of the resulting volume definitions for radiotherapy. The results of our limited study, based on the margins used, indicate that the CT-defined target volume is consistently larger than that from either of the two MRI modalities and suggest that noncoplanar approaches for its treatment and other local approaches for tumor boost should be considered. We conclude that until more definitive histopathological guidelines correlated to image features have been formulated and agreed upon, one should try to make full use of all available diagnostic information in order to minimize the possibility of geographical miss of target extensions.