scholarly journals A bistable structural element

2008 ◽  
Vol 222 (11) ◽  
pp. 2045-2051 ◽  
Author(s):  
T Schioler ◽  
S Pellegrino
Keyword(s):  
Theoretical Analysis ◽  
Analytical Model ◽  
Mechanical Behaviour ◽  
The Other ◽  
Experimental Measurements ◽  
Structural Element ◽  
High Stiffness ◽  
Revolute Joints ◽  
Prototype Structure ◽  
Good Agreement

This article presents a novel bistable structural element that has high stiffness in stable configurations, but requires only a small amount of energy to be switched from one configuration to the other. The element is based on a planar linkage of four bars connected by revolute joints, braced by tape-spring diagonals. A description of the concept is presented, along with a detailed theoretical analysis of its mechanical behaviour. Experimental measurements obtained from a prototype structure are found to be in very good agreement with the predictions from this analytical model.

Rectilinear low-frequency shear of homogeneously aligned nematic liquid crystals

1993 ◽  
Vol 441 (1913) ◽  
pp. 559-573 ◽  
Keyword(s):  
Thin Film ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Theoretical Analysis ◽  
Low Frequency ◽  
The Other ◽  
Critical Amplitude ◽  
Linear Shear ◽  
Theoretical Results ◽  
Good Agreement

A thin film of nematic liquid crystal (ZLI 1085) is sandwiched between two horizontally mounted glass blocks, whose faces have been treated to align the molecules of the liquid parallel to the plane of the blocks. By moving one block relative to the other in its own plane, the liquid crystal is subjected to an oscillatory linear shear. Above a certain frequency-dependent amplitude, mechanical Williams domains of alternating bright and dark stripes are observed perpendicular to the direction of shear. A theoretical analysis of this phenomenon is carried out to provide predictions for both the thickness of the stripes and the critical amplitude as a function of frequency. Good agreement is found between the experimental and theoretical results.

The Separation of Light Gaseous Isotopes by Mass Diffusion Columns II

1964 ◽  
Vol 19 (6) ◽  
pp. 747-755
Author(s):  
W. J. De Wet ◽  
J. Los
Keyword(s):  
Theoretical Analysis ◽  
Mass Diffusion ◽  
Experimental Results ◽  
The Other ◽  
Countercurrent Flow ◽  
Gas Solubility ◽  
Flow Rates ◽  
Mixing Effects ◽  
Other Hand ◽  
Good Agreement

The design of mass diffusion columns operated with partition membranes, for the separation of light gaseous isotopes, is discussed. A theoretical analysis of experimental results obtained indicates that a good agreement between experimental results and theory is only obtained at low column pressures and moderate countercurrent flow rates. At fairly low countercurrent flow rates mixing effects due to viscous dragging and gas solubility by the condensate appear to be considerable whereas excessively high countercurrent flow rates, on the other hand, also seem undesirable. Some suggestions are proposed to obviate impairing effects at least to some extent.

scholarly journals Soil Resistance and its Impact on Tillage Depth

2013 ◽  
Vol 16 (1) ◽  
pp. 26-30 ◽  
Author(s):  
František Varga ◽  
Miroslav Mojžiš ◽  
Rudolf Abrahám
Keyword(s):  
Theoretical Analysis ◽  
Control Systems ◽  
Force Control ◽  
Initial Conditions ◽  
The Other ◽  
Experimental Measurements ◽  
Soil Resistance ◽  
Research Development ◽  
Advantages And Disadvantages ◽  
Tillage Depth

Abstract Currently manufactured tractors are equipped with a three-point hitch, which is used to connect semi-mounted implements to the tractor. The tractor three-point hitch is operated hydraulically, using various types of control. The most commonly used control is a force, positional and a mixed one. Each of these types of control has its specific characteristics and some advantages and disadvantages. Finally, each type of control is suitable for certain soil and terrain conditions. Particular attention was paid to a force control, which is improving the use of the tractor with a mounted implement, but on the other hand, adversely affects the uniformity of working depth of implements on soils with variable resistance. Based on theoretical analysis and experimental measurements, there has been determined the effect of soil resistance on the tillage depth, depending on initial conditions for implement deepening. Initial conditions for implement deepening are given by the tillage depth, soil resistance, and the cutting width of a plough. It was found that soil resistance strongly affects the tillage depth, and with increasing soil resistance the tillage depth decreases non-linearly. A gradual increasing of soil resistance is associated with a less-marked decreasing of the tillage depth. These facts will be further used in research, development and experimental verification of new control systems of the three-point hitch of tractors.

Theoretical and experimental research on slip and uplift of the timber-concrete composite beam

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7079-7099
Author(s):  
Jianying Chen ◽  
Guojing He ◽  
Xiaodong (Alice) Wang ◽  
Jiejun Wang ◽  
Jin Yi ◽  
...  
Keyword(s):  
Differential Equations ◽  
Deformation Theory ◽  
Concrete Slab ◽  
Theoretical Calculations ◽  
Structural Element ◽  
Structural Efficiency ◽  
Theoretical Investigations ◽  
New Type ◽  
Interlayer Slip ◽  
Good Agreement

Timber-concrete composite beams are a new type of structural element that is environmentally friendly. The structural efficiency of this kind of beam highly depends on the stiffness of the interlayer connection. The structural efficiency of the composite was evaluated by experimental and theoretical investigations performed on the relative horizontal slip and vertical uplift along the interlayer between composite’s timber and concrete slab. Differential equations were established based on a theoretical analysis of combination effects of interlayer slip and vertical uplift, by using deformation theory of elastics. Subsequently, the differential equations were solved and the magnitude of uplift force at the interlayer was obtained. It was concluded that the theoretical calculations were in good agreement with the results of experimentation.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

scholarly journals Responses of the Pheromone-Binding Protein of the Silk Moth Bombyx mori on a Graphene Biosensor Match Binding Constants in Solution

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 499
Author(s):  
Caroline Bonazza ◽  
Jiao Zhu ◽  
Roger Hasler ◽  
Rosa Mastrogiacomo ◽  
Paolo Pelosi ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Binding Protein ◽  
Binding Constants ◽  
Isoamyl Acetate ◽  
The Other ◽  
Oxide Surface ◽  
Binding Assays ◽  
Pheromone Binding Protein ◽  
Silk Moth ◽  
Good Agreement

An electronic biosensor for odors was assembled by immobilizing the silk moth Bombyx mori pheromone binding protein (BmorPBP1) on a reduced graphene oxide surface of a field-effect transistor. At physiological pH, the sensor detects the B. mori pheromones, bombykol and bombykal, with good affinity and specificity. Among the other odorants tested, only eugenol elicited a strong signal, while terpenoids and other odorants (linalool, geraniol, isoamyl acetate, and 2-isobutyl-3-methoxypyrazine) produced only very weak responses. Parallel binding assays were performed with the same protein and the same ligands, using the common fluorescence approach adopted for similar proteins. The results are in good agreement with the sensor’s responses: bombykol and bombykal, together with eugenol, proved to be strong ligands, while the other compounds showed only poor affinity. When tested at pH 4, the protein failed to bind bombykol both in solution and when immobilized on the sensor. This result further indicates that the BmorPBP1 retains its full activity when immobilized on a surface, including the conformational change observed in acidic conditions. The good agreement between fluorescence assays and sensor responses suggests that ligand-binding assays in solution can be used to screen mutants of a binding protein when selecting the best form to be immobilized on a biosensor.

The Behaviour of Multiple Loops in Torsion

1988 ◽  
Vol 15 (3) ◽  
pp. 149-156 ◽  
Author(s):  
R. A. Cavina ◽  
N. E. Waters
Keyword(s):  
Energy Method ◽  
Strain Energy ◽  
Vertical Axis ◽  
Experimental Measurements ◽  
Complementary Strain ◽  
Radial Axis ◽  
Strain Energy Method ◽  
Good Agreement

The angular stiffness of a multiple looped span, subject to rotation about a vertical axis (torsion) and also to rotation about a horizontal or radial axis (mesio-distal tilt), have been derived using the complementary (strain) energy method. Experimental measurements on enlarged models were in good agreement with the values calculated from the theoretical relationships obtained. The variations in angular stiffness resulting from changes in the loop height, width, and position of clinical sized loops are discussed.

APPLICATION OF A NEW HAMILTONIAN OF INTERACTION TO THREE-DIMENSIONAL STRUCTURES

2004 ◽  
Vol 18 (09) ◽  
pp. 1351-1368
Author(s):  
ANDREI DOLOCAN ◽  
VOICU OCTAVIAN DOLOCAN ◽  
VOICU DOLOCAN
Keyword(s):  
Experimental Data ◽  
Cohesive Energy ◽  
Noble Gases ◽  
Three Dimensional ◽  
The Other ◽  
Ionic Crystals ◽  
Coupling Constant ◽  
Good Agreement

Using a new Hamiltonian of interaction we have calculated the cohesive energy in three-dimensional structures. We have found the news dependences of this energy on the distance between the atoms. The obtained results are in a good agreement with experimental data in ionic, covalent and noble gases crystals. The coupling constant γ between the interacting field and the atoms is somewhat smaller than unity in ionic crystals and is some larger than unity in covalent and noble gases crystals. The formulae found by us are general and may be applied, also, to the other types of interactions, for example, gravitational interactions.

THEORETICAL ANALYSIS AND EXPERIMENT OF A NOVEL DEP CHIP WITH 3-D SILICON ELECTRODES

2005 ◽  
Vol 15 (02) ◽  
pp. 231-236 ◽  
Author(s):  
LIMING YU ◽  
FRANCIS E. H. TAY ◽  
GUOLIN XU ◽  
CIPRIAN ILIESCU ◽  
MARIOARA AVRAM
Keyword(s):  
Theoretical Analysis ◽  
Applied Voltage ◽  
Microfluidic Channel ◽  
The Other ◽  
Yeast Cells ◽  
Applied Potential ◽  
Dielectrophoretic Force ◽  
Joule Effect ◽  
Doped Silicon ◽  
Planar Electrodes

This paper presents a novel dielectrophoresis (DEP) device where the DEP electrodes define the channel walls. This is achieved by fabricating microfluidic channel walls from highly doped silicon so that they can also function as DEP electrodes. Compared with planar electrodes, this device increases the exhibited dielectrophoretic force on the particle, therefore decreases the applied potential and reduces the heating of the solution. A DEP device with triangle electrodes has been designed and fabricated. Compared with the other two configurations, semi-circular and square, triangle electrode presents an increased force, which can decrease the applied voltage and reduce the Joule effect. Yeast cells have been used to for testing the performance of the device.

The Structural Framework of Pictorial Balance

Perception ◽  
1996 ◽  
Vol 25 (12) ◽  
pp. 1419-1436 ◽  
Author(s):  
Paul Locher ◽  
Sharon Gray ◽  
Calvin Nodine
Keyword(s):  
Visual Arts ◽  
Structural Features ◽  
Original Compositions ◽  
The Other ◽  
Global Integration ◽  
Artistic Style ◽  
Structural Framework ◽  
Museum Professionals ◽  
Balance Structure ◽  
Good Agreement

Two experiments were performed to examine how the subjective balance of a painting is created by its structural features and to determine if balance influences the way people look at paintings. Stimuli consisted of sixteen reproductions of twentieth-century paintings varying in artistic style and a reconstructed less-balanced version of each. Participants in experiment 1 determined the location of the balance center of each composition, assigned ‘weights’ to the pictorial features which contributed to the location of the balance center, and rated the picture for balance. It was found that design and museum professionals and individuals untrained in the visual arts were in good agreement as to the structural framework underlying the balance organization of a painting. For all participants, disruption of the balanced organizations of the original compositions led to reliable shifts in the location of the perceived balance centers of the originals compared with their less-balanced perturbations. Additionally, it was observed that particular features as such were not the origin of the balance phenomenon; rather, judgments concerning the balance structure and its center were dependent on the global integration of information across a wide area of the display field, but especially from its central region. Last, the subtle changes in balance structure between versions resulted in lower ratings of balance being assigned to the less-balanced perturbations by the design professionals only; the other two participant groups evaluated overall balance of the versions as comparable. In experiment 2, eye movements of a different group of untrained individuals were recorded as they performed similar tasks on the art stimuli. It was found that disruption of the balance structure of the original representational but not abstract compositions resulted in different regions of the original and perturbed versions being visually explored. Findings of both experiments are related to theoretical notions of balance.

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