Abstract The study investigates the bending strength of tracks of box headers beyond AISI, which considers the capacity of individual channels alone. Both experimental and FEM are used, and the ...results are compared to AISI. The findings highlight tracks' significant role in the overall bending capacity. AISI is found to be conservative by 34% to 152%. Failure mode is different from code theoretical expectations for a single channel. Fastener close spacing marginally improves the capacity, while side fasteners offer significant enhancement, but track widening limits this enhancement. A modification to AISI is proposed considering track strength, with outcomes showing good accuracy.
CrystalExplorer is a native cross‐platform program supported on Windows, MacOS and Linux with the primary function of visualization and investigation of molecular crystal structures, especially ...through the decorated Hirshfeld surface and its corresponding two‐dimensional fingerprint, and through the visualization of void spaces in the crystal via isosurfaces of the promolecule electron density. Over the past decade, significant changes and enhancements have been incorporated into the program, such as the capacity to accurately and quickly calculate and visualize quantitative intermolecular interactions and, perhaps most importantly, the ability to interface with the Gaussian and NWChem programs to calculate quantum‐mechanical properties of molecules. The current version, CrystalExplorer21, incorporates these and other changes, and the software can be downloaded and used free of charge for academic research.
CrystalExplorer is a native cross‐platform program for the visualization and investigation of molecular crystal structures.
The present study is focused on tubular multi-channel arrays composed of commercial fluoropolymer (FEP) tubes with different wall thickness. After proper charging in a high electric field, such ...tubular structures exhibit a large piezoelectric \{{\boldsymbol{d}}}_{{\bf{33}}}\ coefficient significantly exceeding the values of classical polymer ferroelectrics and being even comparable to conventional lead-free piezoceramics. The quasistatic piezoelectric \{{\boldsymbol{d}}}_{{\bf{33}}}\ coefficient was theoretically derived and its upper limits were evaluated considering charging and mechanical properties of the arrays. In order to optimize the \{{\boldsymbol{d}}}_{{\bf{33}}}\ coefficient the remanent polarization and the mechanical properties were taken into account, both being strongly dependent on the air channel geometry as well as on the wall thickness of the FEP tubes. The model predictions are compared with experimental d33 coefficients for two particular arrays with equal air gaps of 250 μm, but with different wall thickness of utilized FEP tubes of 50 μm and 120 μm, respectively. Analytical modeling allows for the prediction that arrays made of FEP tubes with a wall thickness of 10 μm are foreseen to exhibit a superb piezoelectric response of up to 600 pC/N if the height of stadium-like shaped air channels is reduced down to 50 μm, making them potentially interesting for application as highly sensitive sensors and energy harvesting.
This book relates the mechanical and structural properties of bone to its function in man and other vertebrates. John Currey, one of the pioneers of modern bone research, reviews existing information ...in the field and particularly emphasizes the correlation of the structure of bone with its various uses.
Originally published in 1984.
ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.
This authoritative, widely cited book has been used all over the world. The Fourth Edition incorporates the latest developments in the field while maintaining the core objectives of previous ...editions: To correlate properties with chemical structure and to describe methods that permit the estimation and prediction of numerical properties from chemical structure, i.e. nearly all properties of the solid, liquid, and dissolved states of polymers.
•A holistic review of current research on the mechanical properties of AAC is provided.•The AACs reviewed include slag-based, fly ash-based, and fly ash/slag-based types.•Both static and dynamic ...mechanical properties of AAC are discussed.•The fracture, bond and high-temperature properties of AAC are also addressed.•The slag/fly ash ratio is a very influential factor to the mechanical properties of AAC.
Alkali-activated concretes (AACs) are attracting increasing attention due to their potential as alternatives to ordinary Portland cement concrete (OPCC). This paper is a holistic review of current research on the mechanical properties of AAC including research on its compressive strength, tensile strength, elastic modulus, Poisson’s ratio, stress–strain relationship under uniaxial compression, fracture properties, bond mechanism with steel reinforcement, dynamic mechanical properties, and high-temperature performance. Three types of AAC are reviewed: alkali-activated slag, alkali-activated fly ash, and alkali-activated slag-fly ash concretes. The applicability to AAC of design formulas found in codes of practice that were developed to estimate the basic mechanical performances of OPCC is also discussed. It is shown that, in general, AAC exhibits better bond performance with steel reinforcement and better strength performance after exposure to elevated temperatures than OPCC. For the other reviewed mechanical properties, the differences between AAC and OPCC largely depend on the proportions of raw materials in the concrete; specifically, the slag to fly ash ratio may be a very influential factor. As there is a trend to combine slag and fly ash in the production of AAC to achieve normal temperature curing and environmental friendliness, further research is deemed necessary to determine how the slag to fly ash ratio influences the fundamental mechanical properties of AAC and how this affects practical designs.
Aromatic nucleophilic substitution polymerization was used to synthesize five poly(ether nitrile imide)s (PENIs) that include benzonitrile and bulky cardo groups from a mixture of phenolphthalein ...(PP), 4,4'-bis(4-fluorophthalimide) diphenyl ether (4,4'-BFPI), and 2,6-difluorobenzonitrile (DFBN). The structure and properties relationship of PENIs with different ratios of DFBN and 4,4'-BFPI was explored. It was found that the glass transition temperature (T.sub.g) of PENIs decreased from 280 to 260degrees C, while the temperature of 5% thermal weight loss (T.sub.5%) in N.sub.2 increased from 429 to 453degreesC as the benzonitrile content in PENI increased. The produced PENI films had good mechanical characteristics, including tensile strengths of 103-112 MPa, elongations at break of 5.6%8.2%, and tensile moduli of 2.9-3.4 GPa. Furthermore, the solubility and melt processability were also improved with the introduction of the benzonitrile group. Compared with poly(ether ketone imide)s (PEKIs) and poly(ether sulfone imide)s (PESIs), PENIs with benzonitrile displayed higher T.sub.g, tensile modules, and lower complex viscosity.
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