scholarly journals Design of Class 4 Hollow Structural Section Compression Members

2020 ◽  
Author(s):  
Justin H. Thomas ◽  
Kyle Tousignant
Keyword(s):  
Aspect Ratio ◽  
Yield Stress ◽  
Effective Area ◽  
New Method ◽  
Effective Width ◽  
Safe Method ◽  
Compression Members ◽  
Effective Yield ◽  
Nominal Capacity ◽  
Hollow Structural Section

This paper presents a study on the CSA S16:19, AISC 360-16, and EN 1993-1-1 approaches to determine the nominal capacity (Cn) of Class 4 hollow structural section (HSS) compression members. Class 3 limits and effective width (be) equations are compared, and the effect of member slenderness (KL/r), width-(or diameter-)to-thickness ratio, and height-to-width (or aspect) ratio on the relative Cn predictions are evaluated. For Class 4 rectangular hollow sections, CSA S16:19 is shown to under-predict Cn by up to 34% relative to AISC 360-16. A more economical, yet still safe, method to calculate be (and hence, Cn) is proposed. For Class 4 circular hollow sections (CHS), a new method to calculate Cn utilizing the “effective area method” is proposed. This new method removes the need for having an “effective yield stress method” in CSA S16 Clause 13.3.4.

scholarly journals Investigation of Thick-Film-Paste Rheology and Film Material for Pattern Transfer Printing (PTP) Technology

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 108
Author(s):  
Adrian Adrian ◽  
Dominik Rudolph ◽  
Jan Lossen ◽  
Norbert Willenbacher
Keyword(s):  
Solar Cell ◽  
Aspect Ratio ◽  
Yield Stress ◽  
Laser Power ◽  
Light Transmission ◽  
Pattern Transfer ◽  
Volatile Components ◽  
Film Material ◽  
Transfer Printing ◽  
Power Threshold

Steady cost pressure in silicon solar cell production leads to a continuous reduction of silver consumption per cell. Pattern Transfer Printing (PTP) technology enables to reduce silver consumption by depositing smaller front electrodes on solar cells. Here, we aim at a better understanding of the laser deposition process. The aspect ratio of printed lines improved with increasing paste yield stress but was lower than the theoretical aspect ratio for a given trench geometry, suggesting that line spreading was caused by the pressure that was due to the vaporization of volatile paste components and a yield stress reduction that was due to local paste heating. A low laser power threshold, mandatory to fabricate narrow electrodes with a high aspect ratio and low amount of debris, could be achieved using pastes with low boiling temperature of volatile components and poor wetting between paste and film. The material with the lowest light transmission exhibited the lowest laser power threshold. We attribute this to the weaker adhesion to the paste and a better alignment with the laser focal plane. Our results provide valuable guidelines for paste and film material design aimed at narrower electrodes, with a higher aspect ratio to be obtained at an even lower laser power threshold in PTP-based solar cell metallization.

A new method for determining platy particle aspect ratio: A kaolinite case study

2014 ◽  
Vol 97-98 ◽  
pp. 125-131 ◽  
Author(s):  
Hongfei Cheng ◽  
Zhiliang Zhang ◽  
Qinfu Liu ◽  
Joseph Leung
Keyword(s):  
Aspect Ratio ◽  
New Method ◽  
Particle Aspect Ratio

Effects of cross-sessional area and aspect ratio coupled with orientation on mechanical properties and deformation behavior of Cu nanowires

2021 ◽  
Author(s):  
Hui Cao ◽  
Wenke Chen ◽  
Zhiyuan Rui ◽  
Changfeng Yan
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Cu Nanowires ◽  
The Cross

Abstract Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young’s modulus and the yield stress sharply increase with the aspect ratio except for the <110>{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young’s modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young’s modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the <111> Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm2, the surface force decreases with the aspect ratio of the <110> Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young’s modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.

Extraction of Lipid-Soluble Marine Biotoxins

1995 ◽  
Vol 78 (2) ◽  
pp. 480-482 ◽  
Author(s):  
Donald J Hannah ◽  
Desmond G Till ◽  
Terry Deverall ◽  
Paul D Jones ◽  
Joanne M Fry
Keyword(s):  
New Zealand ◽  
Saline Solution ◽  
Extraction Methods ◽  
New Method ◽  
Mouse Bioassay ◽  
Shellfish Poisoning ◽  
Constant Weight ◽  
Lipophilic Compounds ◽  
Safe Method ◽  
Marine Biotoxins

Abstract A recent extensive outbreak of toxic shellfish poisoning (TSP) in New Zealand, with at least 4 types of toxicities present, required the development of a new method for detecting lipid-soluble marine biotoxins. The complexity of studying this outbreak, requiring large sample numbers, dictated the development of a robust and safe method for extracting lipid-soluble toxins. The new method is based on extraction of lipophilic compounds with acetone followed by partitioning into dichloromethane. The dichloromethane extract is evaporated to constant weight and suspended in a detergent–saline solution for use in a mouse bioassay. The new method produces an extract of superior quality, is quicker and more sensitive compared with extraction methods currently used.

A New Method of Preparing Artificial Cores with Certain Cracks for Experiment Study of Elastic Wave Propagation

2011 ◽  
Vol 356-360 ◽  
pp. 2954-2957 ◽  
Author(s):  
Zi Zhen Wang ◽  
Ri He Wang ◽  
Yu Huan Bu ◽  
Xun Shan
Keyword(s):  
Wave Propagation ◽  
Aspect Ratio ◽  
Elastic Wave ◽  
Steel Sheet ◽  
Crack Opening ◽  
Elastic Wave Propagation ◽  
New Method ◽  
Thin Steel Sheet ◽  
Fractured Medium ◽  
Thin Steel

Crack universally existing underground is an important kind of pores. In order to study the elastic wave propagation in fractured medium through experiment, a new method to make artificial core with certain cracks using oil well cement and camphor sheet or thin steel sheet is put forward. Geometric parameters of the crack, such as shape, size and aspect ratio, are approximately equal to that of camphor sheet or thin steel sheet. Using the thin steel sheet to make crack can be more easy and accurate to control the crack angle than using camphor sheet. The crack opening scales at millimeters. The aspect ratio of cracks formed by camphor sheet ranges from 1.4 to 8, and aspect ratio of cracks formed by thin steel sheet ranges from 2.5 to 70. This method is proved simple and feasible by experiment practice, which can provide artificial cores with certain crack for acoustic wave propagation study.

On a New Method to Determine the Yield Stress in Lubricating Grease

2015 ◽  
Vol 58 (6) ◽  
pp. 1021-1030 ◽  
Author(s):  
F. Cyriac ◽  
P. M. Lugt ◽  
R. Bosman
Keyword(s):  
Yield Stress ◽  
New Method ◽  
Lubricating Grease

scholarly journals Nanostructured Electrodes for Improved Neural Recording

2002 ◽  
Vol 729 ◽  
Author(s):  
Karen C. Cheung ◽  
Yang-Kyu Choi ◽  
Tim Kubow ◽  
Luke P. Lee
Keyword(s):  
Cell Culture ◽  
Surface Roughness ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Electrode Surface ◽  
Neural Recording ◽  
New Method ◽  
Nanostructured Electrodes

AbstractWe present a new method of increasing the effective electrode surface for improved neural recording. To optimize the electrode, the impedance can be decreased by introducing surface roughness or nanostructures on the electrode. High aspect ratio pillar-like polysilicon nanostructures are created in a reactive ion etch. Nanostructure robustness in cell culture is examined.

A Novel Method to Fabricate High Aspect Ratio Microcoils

2014 ◽  
Vol 543-547 ◽  
pp. 600-603 ◽  
Author(s):  
Wen Jun Gu ◽  
Shi Sun ◽  
Xu Han Dai ◽  
Gui Fu Ding
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
New Method ◽  
Liga Technology ◽  
Novel Method

In this study, we developed a new method to fabricate microcoils with narrow and high aspect ratio coil lines using TSV and UV-LIGA technology in a SU-8 mold. The combination of SU-8 and TSV makes it possible to fabricate microstructures with high aspect ratio. TSV technology resolved the difficulties of electroplating with high aspect ratio. We designed and fabricated microcoils consisiting of coil lines with widths of 15μm and aspect ratio of 2.

scholarly journals Simulating Biofilm Deformation and Detachment with the Immersed Boundary Method

2016 ◽  
Vol 19 (3) ◽  
pp. 682-732 ◽  
Author(s):  
Rangarajan Sudarsan ◽  
Sudeshna Ghosh ◽  
John M. Stockie ◽  
Hermann J. Eberl
Keyword(s):  
Shear Stress ◽  
Aspect Ratio ◽  
Yield Stress ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Spatial Proximity ◽  
Critical Threshold ◽  
Immersed Boundary ◽  
Stress Profile ◽  
Equivalent Continuum

AbstractWe apply the immersed boundary (or IB) method to simulate deformation and detachment of a periodic array of wall-bounded biofilm colonies in response to a linear shear flow. The biofilm material is represented as a network of Hookean springs that are placed along the edges of a triangulation of the biofilm region. The interfacial shear stress, lift and drag forces acting on the biofilm colony are computed by using fluid stress jump method developed by Williams, Fauci and Gaver [Disc. Con-tin. Dyn. Sys. B11(2):519–540, 2009], with a modified version of their exclusion filter. Our detachment criterion is based on the novel concept of an averaged equivalent continuum stress tensor defined at each IB point in the biofilm which is then used to determine a corresponding von Mises yield stress; wherever this yield stress exceeds a given critical threshold the connections to that node are severed, thereby signalling the onset of a detachment event. In order to capture the deformation and detachment behaviour of a biofilm colony at different stages of growth, we consider a family of four biofilm shapes with varying aspect ratio. For each aspect ratio, we varied the spacing between colonies to investigate role of spatial clustering in offering protection against detachment. Our numerical simulations focus on the behaviour of weak biofilms (with relatively low yield stress threshold) and investigate features of the fluid-structure interaction such as locations of maximum shear and increased drag. The most important conclusions of this work are: (a) reducing the spacing between colonies reduces drag by from 50 to 100% and alters the interfacial shear stress profile, suggesting that even weak biofilms may be able to grow into tall structures because of the protection they gain from spatial proximity with other colonies; (b) the commonly employed detachment strategy in biofilm models based only on interfacial shear stress can lead to incorrect or inaccurate results when applied to the study of shear induced detachment of weak biofilms. Our detachment strategy based on equivalent continuum stresses provides a unified and consistent IB framework that handles both sloughing and erosion modes of biofilm detachment, and is consistent with strategies employed in many other continuum based biofilm models.

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