scholarly journals Learning to perceive the relative mass of colliding balls: The effects of ratio scaling and feedback

2000 ◽  
Vol 62 (7) ◽  
pp. 1332-1340 ◽  
Author(s):  
David M. Jacobs ◽  
Claire F. Michaels ◽  
Sverker Runeson
Keyword(s):  
Relative Mass ◽  
Colliding Balls ◽  
Ratio Scaling

scholarly journals Windblown Sand-Induced Degradation of Glass Panels in Curtain Walls

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 607
Author(s):  
Yuxi Zhao ◽  
Rongcheng Liu ◽  
Fan Yan ◽  
Dawei Zhang ◽  
Junjin Liu
Keyword(s):  
Visible Light ◽  
Mass Loss ◽  
Effective Area ◽  
Area Ratio ◽  
Light Transmittance ◽  
Relative Mass ◽  
Impact Time ◽  
Windblown Sand ◽  
Glass Panels ◽  
The Impact

The windblown sand-induced degradation of glass panels influences the serviceability and safety of these panels. In this study, the degradation of glass panels subject to windblown sand with different impact velocities and impact angles was studied based on a sandblasting test simulating a sandstorm. After the glass panels were degraded by windblown sand, the surface morphology of the damaged glass panels was observed using scanning electron microscopy, and three damage modes were found: a cutting mode, smash mode, and plastic deformation mode. The mass loss, visible light transmittance, and effective area ratio values of the glass samples were then measured to evaluate the effects of the windblown sand on the panels. The results indicate that, at high abrasive feed rates, the relative mass loss of the glass samples decreases initially and then remains steady with increases in impact time, whereas it increases first and then decreases with an increase in impact angle such as that for ductile materials. Both visible light transmittance and effective area ratio decrease with increases in the impact time and velocities. There exists a positive linear relationship between the visible light transmittance and effective area ratio.

scholarly journals Locomotor Anatomy and Behavior of Patas Monkeys (Erythrocebus patas) with Comparison to Vervet Monkeys (Cercopithecus aethiops)

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Adrienne L. Zihlman ◽  
Carol E. Underwood
Keyword(s):  
Cercopithecus Aethiops ◽  
Whole Body ◽  
Relative Mass ◽  
Vervet Monkeys ◽  
Long Distance ◽  
Erythrocebus Patas ◽  
Locomotor System ◽  
Patas Monkeys ◽  
Foot Bones ◽  
Muscle Groups

Patas monkeys (Erythrocebus patas) living in African savanna woodlands and grassland habitats have a locomotor system that allows them to run fast, presumably to avoid predators. Long fore- and hindlimbs, long foot bones, short toes, and a digitigrade foot posture were proposed as anatomical correlates with speed. In addition to skeletal proportions, soft tissue and whole body proportions are important components of the locomotor system. To further distinguish patas anatomy from other Old World monkeys, a comparative study based on dissection of skin, muscle, and bone from complete individuals of patas and vervet monkeys (Cercopithecus aethiops) was undertaken. Analysis reveals that small adjustments in patas skeletal proportions, relative mass of limbs and tail, and specific muscle groups promote efficient sagittal limb motion. The ability to run fast is based on a locomotor system adapted for long distance walking. The patas’ larger home range and longer daily range than those of vervets give them access to highly dispersed, nutritious foods, water, and sleeping trees. Furthermore, patas monkeys have physiological adaptations that enable them to tolerate and dissipate heat. These features all contribute to the distinct adaptation that is the patas monkeys’ basis for survival in grassland and savanna woodland areas.

Ratio scaling of psychological magnitude

1992 ◽  
Vol 9 (1) ◽  
pp. 164-166
Author(s):  
Howard R. Moskowitz
Keyword(s):  
Ratio Scaling

Motion of masses with asymmetric and symmetric friction. Application to fault sliding

2021 ◽  
Author(s):  
Rui Xiang Wong ◽  
Elena Pasternak ◽  
Arcady Dyskin
Keyword(s):  
Frictional Force ◽  
Normal Load ◽  
Power Spectra ◽  
Inertial Force ◽  
Friction Reduction ◽  
Relative Mass ◽  
Hydraulic Fractures ◽  
Driving Frequency ◽  
Stick Slip ◽  
Friction Forces

<p>This study analyses a situation when a geological fault contains a section of anisotropic gouge with inclined symmetry axes (e.g. inclined layering), Bafekrpour et al. [1]. Such gouge in a constrained environment induces, under compression, asymmetric friction (different friction forces resisting sliding in the opposite directions). The rest of the gouge produces conventional symmetric friction. A mass-spring model of the gouge with asymmetric and symmetric friction sections is proposed consisting of a mass with asymmetric friction connected through a spring to another mass with symmetric friction. These masses are set on a base subjected to vibration. A parametric analysis is performed on this system. Two distinct characteristic regimes were observed: <em>recurrent movement</em> resembling stick-slip motion similar to predicted by [2] and <em>sub-frictional movement</em>. Recurrent movement arises when the inertial force is sufficient to overcome frictional force of a block with symmetric friction. Sub-frictional movement occurs when the inertial force is not sufficient to overcome frictional force of an equivalent system with only symmetric friction. The sub-frictional movement is produced by the force in the connecting spring increased due to the movement of the asymmetric friction block in the direction characterised by low friction. We formulate the criterion at which sub-frictional movement occurs. The occurrence of sub-frictional depends upon the relative mass of the symmetric and asymmetric friction sections, as well as the amplitude and driving frequency of the excitation. Power spectra of the produced vibrations are determined for both regimes. The results can shed light on mechanisms of sliding over pre-existing discontinuities and their effect on seismic event generation and propagation of hydraulic fractures in the presence of discontinuities.</p><p>[1] Bafekrpour,<strong> </strong>E., A.V. Dyskin, E. Pasternak, A. Molotnikov and Y. Estrin (2015), Internally architectured materials with directionally asymmetric friction. <em>Scientific Reports</em>, 5, Article 10732.</p><p>[2] Pasternak, E. A.V. Dyskin and I. Karachevtseva, 2020. Oscillations in sliding with dry friction. Friction reduction by imposing synchronised normal load oscillations. <em>International Journal of Engineering Science</em>, 154, 103313.</p><p><strong>Acknowledgement</strong>. AVD and EP acknowledge support from the Australian Research Council through project DP190103260.</p>

Rapid qualitative changes in mRNA populations in cultured human lymphocytes: comparison of the effects of cycloheximide and concanavalin A

1984 ◽  
Vol 62 (9) ◽  
pp. 859-864 ◽  
Author(s):  
Donald R. Forsdyke
Keyword(s):  
Concanavalin A ◽  
Human Lymphocytes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Lymphocyte Activation ◽  
Relative Mass ◽  
Protein Synthesis Inhibitor ◽  
Synthesis Inhibitor ◽  
Mrna Species ◽  
Reticulocyte Lysate ◽  
Qualitative Changes

To examine the hypothesis that the stimulation of cultured lymphocytes by lectins involves the inactivation of a protein repressor of putative "activation genes," the effects of a protein synthesis inhibitor (cycloheximide) and a lectin (concanavalin A) were compared. Qualitative changes in mRNA populations were assessed by translating RNA prepared from cycloheximide- or lectin-treated cultures in a rabbit reticulocyte lysate. [35S]Methionine-labelled translation products were analysed by two-dimensional polyacrylamide gel electrophoresis. Cycloheximide increased the radioactive labelling of cultured lymphocytes with the RNA precursor [3H]uridine, as previously reported. This was observed during the first 3 h of culture; thereafter, cycloheximide was inhibitory. The period of increased labelling with [3H]uridine coincided with a period of great increase in mRNA corresponding to an acidic protein of a relative mass of approximately 55 000. This mRNA was not detected in RNA prepared from control cultures, but was one of the most abundant mRNA species detected in RNA prepared from cycloheximide-treated cultures. Increases in certain less abundant mRNA species were also noted. However, the mRNAs were not observed in RNA prepared from lectin-treated cultures. If an increase in these mRNAs is important for lymphocyte activation, then the increase must be to an extent not detected by our current methods.

scholarly journals Investigation of water adsorption and hygroscopicity of atmospherically relevant particles using a commercial vapor sorption analyzer

2017 ◽  
Vol 10 (10) ◽  
pp. 3821-3832 ◽  
Author(s):  
Wenjun Gu ◽  
Yongjie Li ◽  
Jianxi Zhu ◽  
Xiaohong Jia ◽  
Qinhao Lin ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Radiative Forcing ◽  
Water Adsorption ◽  
Theoretical Data ◽  
Atmospheric Particles ◽  
Relative Mass ◽  
Nonspherical Particles ◽  
Vapor Sorption ◽  
Hygroscopic Growth ◽  
Dry Conditions

Abstract. Water adsorption and hygroscopicity are among the most important physicochemical properties of aerosol particles, largely determining their impacts on atmospheric chemistry, radiative forcing, and climate. Measurements of water adsorption and hygroscopicity of nonspherical particles under subsaturated conditions are nontrivial because many widely used techniques require the assumption of particle sphericity. In this work we describe a method to directly quantify water adsorption and mass hygroscopic growth of atmospheric particles for temperature in the range of 5–30 °C, using a commercial vapor sorption analyzer. A detailed description of instrumental configuration and experimental procedures, including relative humidity (RH) calibration, is provided first. It is then demonstrated that for (NH4)2SO4 and NaCl, deliquescence relative humidities and mass hygroscopic growth factors measured using this method show good agreements with experimental and/or theoretical data from literature. To illustrate its ability to measure water uptake by particles with low hygroscopicity, we used this instrument to investigate water adsorption by CaSO4 ⋅ 2H2O as a function of RH at 25 °C. The mass hygroscopic growth factor of CaSO4 ⋅ 2H2O at 95 % RH, relative to that under dry conditions (RH  < 1 %), was determined to be (0.450±0.004) % (1σ). In addition, it is shown that this instrument can reliably measure a relative mass change of 0.025 %. Overall, we have demonstrated that this commercial instrument provides a simple, sensitive, and robust method to investigate water adsorption and hygroscopicity of atmospheric particles.

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