Conversaziones and Reception, 1975

1976 ◽  
Vol 30 (2) ◽  
pp. 117-126
Keyword(s):  
Low Power ◽  
Resonance Frequency ◽  
Sliding Friction ◽  
Applied Physics ◽  
Irrigation Systems ◽  
Stirling Cycle ◽  
Potential Applications ◽  
Electrical Generator ◽  
Mechanical Generator ◽  
Coupling Mechanisms

Conversaziones were held this year on 8 May and 26 June. At the first conversazione twenty-five exhibits and two films were shown. Frictionless Stirling-cycle engines were demonstrated by the Electronics and Applied Physics Division, U.K.A.E.A., Harwell. Conventional Stirlingcycle engines running at low power levels are extremely inefficient, owing mainly to the sliding friction associated with the pistons and their coupling mechanisms. Two types of frictionless Stirling-cycle engines have been developed at Harwell. In the thermo-mechanical generator, the output piston of such an engine is replaced by a diaphragm coupled to an electrical generator and the displacer piston is spring mounted, out of contact with the cylinder. The two spring/mass systems are coupled by their common fixing point. This self-starting, frictionless Stirling-cycle engine takes up its own resonance frequency when heat is applied, and has an efficiency of 15% at a 25 W output. An operational prototype generator driving a small television set was shown. Fluidyne is a self-excited, freely oscillating Stirling-cycle engine which needs no solid moving parts and consists simply of two U-tubcs partially filled with liquid; three of the four ends of the U-tubes are connected together through a gas-filled space. The Fluidyne engine has potential applications as a simple pump, e.g. in irrigation systems using solar heat and several versions of the system were shown in operation.

Homokinetic Shaft-Coupling Mechanisms via Double Schoenflies-Motion Generators

2014 ◽  
Author(s):  
Chung-Ching Lee ◽  
Jacques M. Hervé
Keyword(s):  
Lie Group ◽  
Constant Velocity ◽  
Geometric Constraints ◽  
Algebraic Properties ◽  
Potential Applications ◽  
Mechanical Generator ◽  
Displacement Group ◽  
Group Compositions ◽  
Coupling Mechanisms ◽  
Group Product

The paper begins with introducing the 5-dimensional (5D) double Schoenflies-motion (X-X motion) set employing the group product of two 4D X-motion subgroups of displacements. Two families of primitive X-X motion generators are briefly outlined. Then, the geometric constraints for homokinetic transmission via Lie-group-algebraic properties of the displacement set are established. After that, using the described mechanical generators of X-X motion as the basic building cell, we geometrically generate two major families of homokinetic shaft-coupling mechanisms characterized by a subchain with a mechanical generator of 5D X-X motion set of displacement. The obtained constant-velocity shaft couplings (CVSC) are isoconstrained linkages with two parallel shaft axes, which will be less sensitive to manufacture errors. In addition, by means of the reordering method for displacement group compositions, more CVSC mechanisms can be further obtained. The simple or special findings stemming from the proposed general architectures are presented for the potential applications too.

scholarly journals Modelling of a Low Frequency Based Rectangular Shape Piezoelectric Cantilever Beam for Energy Harvesting Applications

2018 ◽  
Vol 12 (1) ◽  
pp. 290
Author(s):  
Ramizi Mohamed ◽  
Mahidur R. Sarker ◽  
Azah Mohamed
Keyword(s):  
Energy Harvesting ◽  
Low Power ◽  
Resonance Frequency ◽  
Cantilever Beam ◽  
Geometric Model ◽  
Low Frequency ◽  
Clean Energy ◽  
Rectangular Shape ◽  
Piezoelectric Cantilever ◽  
Energy Harvesting Devices

<p>Harvesting few amount of charge from environmental ambient sources namely, wind, thermal, heat, vibration, solar utilizing micro scale energy harvesting devices, offers vast view of powering for numerous portable low power electronic devices. However, power harvesting using piezoelectric crystal from low power ambient source nowdays has increasing popularity with the advantages of low cost, long life time, stability and clean energy.  Recent trends have shown that most researchers are interested in designing a low resonance frequency vibration based energy harvesting devices despite of its challenges ahead. In this paper, a low frequency based rectangular shape piezoelectric cantilever beam has been developed for energy harvesting applications. The proposed vibration based low frequency cantilever beam using piezoelectric element has been developed by finite element analysis (FEA) employing COMSOL Multiphysics platform. The main goal of the study is to analyze the outcome of geometric model of a piezoelectric cantilever beam and to calculate the resonance frequency of the structure according to its length. The material of PZT-5H, has been considered to enhance the efficiency of the low frequency based cantilever beam. Finally, the proposed result is compared with other existing works.</p>

LEFT-HANDNESS IN A FOUR-LEVEL ATOMIC SYSTEM

2009 ◽  
Vol 07 (04) ◽  
pp. 747-754 ◽  
Author(s):  
SHUNCAI ZHAO ◽  
ZHENGDONG LIU
Keyword(s):  
Resonance Frequency ◽  
Frequency Band ◽  
Quantum Coherence ◽  
Atomic System ◽  
Negative Permittivity ◽  
Negative Permeability ◽  
Potential Applications

A scheme is proposed for realizing simultaneous negative permittivity and negative permeability based on quantum coherence in a four-level dense atomic system here. Under some parametric conditions the system shows that simultaneous negative permittivity and negative permeability (i.e. Left-handness) can be achieved in a wider frequency band because of quantum coherence. And the novelty properties of gain and dispersion near the resonance frequency may have some potential applications.

scholarly journals Opto-thermophoretic fiber tweezers

Nanophotonics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 475-485 ◽  
Author(s):  
Abhay Kotnala ◽  
Yuebing Zheng
Keyword(s):  
Additive Manufacturing ◽  
Optical Fiber ◽  
Low Power ◽  
Single Particle ◽  
Life Sciences ◽  
Cell Interactions ◽  
Colloidal Assembly ◽  
Single Nanoparticle ◽  
Potential Applications ◽  
Functional Versatility

AbstractRecent advances in opto-thermophoretic tweezers open new avenues for low-power trapping and manipulation of nanoparticles with potential applications in colloidal assembly, nanomanufacturing, life sciences, and nanomedicine. However, to fully exploit the opto-thermophoretic tweezers for widespread applications, the enhancement of their versatility in nanoparticle manipulations is pivotal. For this purpose, we translate our newly developed opto-thermophoretic tweezers onto an optical fiber platform known as opto-thermophoretic fiber tweezers (OTFT). We have demonstrated the applications of OTFT as a nanoparticle concentrator, as a nanopipette for single particle delivery, and as a nanoprobe. The simple setup and functional versatility of OTFT would encourage its use in various fields such as additive manufacturing, single nanoparticle-cell interactions, and biosensing.

Case Studies in the Challenge of Properties Design at Nanoscale

2017 ◽  
pp. 148-184
Author(s):  
Marilena Ferbinteanu ◽  
Harry Ramanantoanina ◽  
Fanica Cimpoesu
Keyword(s):  
Case Studies ◽  
Coordination Compounds ◽  
New Technologies ◽  
Molecular Magnetism ◽  
Structure Property ◽  
Potential Applications ◽  
Polynuclear Coordination Compounds ◽  
Coordination Systems ◽  
Coupling Mechanisms ◽  
Structure Calculations

In the quest for nano-sized materials with potential applications in new technologies and devices, the molecular magnetism based on coordination systems shows a valuable path, including the idea of structure-property rationales. Polynuclear coordination compounds are already in the range of nanometers and many consecrated magnetic materials that can be prepared at nano-scale granulation, such as oxides, have as bonding and exchange coupling mechanisms the same causal engines identified in coordination systems. Based on this paradigm, several case studies are taken, relating the magnetic properties with methods of electron structure calculations and phenomenological models.

scholarly journals Thermally Stable Wireless Patch Antenna Sensor for Strain and Crack Sensing

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3835
Author(s):  
Dan Li ◽  
Yang Wang
Keyword(s):  
Resonance Frequency ◽  
Frequency Shift ◽  
Patch Antenna ◽  
Substrate Material ◽  
Structural Safety ◽  
Thermally Stable ◽  
Strain Sensing ◽  
Sensor Performance ◽  
Resonance Frequency Shift ◽  
Potential Applications

Strain and crack are critical indicators of structural safety. As a novel sensing device, a patch antenna sensor can be utilized to wirelessly estimate structural strain and surface crack growth through resonance frequency shift. The main challenges for the sensor are other effects such as temperature fluctuation that can generate unwanted resonance frequency shift and result in large noise in the measurement. Another challenge for existing designs of patch antenna sensor is the limited interrogation distance. In this research, thermally stable patch antenna sensors are investigated for more reliable measurement. Fabricated on a substrate material with a steady dielectric constant, a new passive (battery-free) patch antenna sensor is designed to improve reliability under temperature fluctuations. In addition, another newly designed dual-mode patch antenna sensor is proposed to achieve a longer interrogation distance. Extensive experiments are conducted to characterize the patch antenna sensor performance, including thermal stability, tensile strain sensing, and emulated crack sensing. The two new patch antenna sensors are demonstrated to be effective in wireless strain and crack measurements and have potential applications in structural health monitoring (SHM).

Four-State Straintronics: Extremely Low Power Nanomagnetic Logic Using Multiferroics With Biaxial Anisotropy

2011 ◽  
Author(s):  
Noel M. D’Souza ◽  
Jayasimha Atulasimha ◽  
Supriyo Bandyopadhyay
Keyword(s):  
Low Power ◽  
Piezoelectric Layer ◽  
Logic Gate ◽  
Magnetic Layer ◽  
Logic Circuits ◽  
Ultra Low Power ◽  
Nanomagnetic Logic ◽  
Cmos Transistor ◽  
Potential Applications ◽  
Novel Concept

The authors had previously theoretically demonstrated that multiferroic nanomagnetic logic can be clocked in ∼1 GHz with few 100 kT/bit power dissipation which is ∼3 orders of magnitude more energy efficient than current CMOS transistor technology that dissipates several 100,000 kT/bit.. In this work, we propose the more novel concept of 4-state logic by numerically demonstrating the feasibity of an ultra low-power 4-state NOR logic gate using multiferroic nanomagnets with biaxial magnetocrystalline anisotropy. Here, the logic bits are encoded in the magnetization orientation of a nanoscale magnetostrictive layer elastically coupled to a piezoelectric layer. The piezoelectric layer can be clocked with a small electrostatic potential (∼0.2 V) to switch the magnetization of the magnetic layer. We also address logic propagation, where the accurate and unidirectional transfer of data from an input nanomagnet along an array of nanomagnets is needed. This is accomplished by devising an effective clocking scheme to the nanomagnet array, which allows for the realization of feasible logic circuits. Ultimately, this technology would enable higher order information processing, such as pattern recognition, to be performed in parallel at very high speeds while consuming extremely low power. Potential applications include high-density logic circuits, associative memory and neuromorphic computing.

A conversion-type electrochemical artificial synapse for plasticity modulation and dendritic application

2021 ◽  
Author(s):  
Huanhuan Wei ◽  
Haiyang Yu ◽  
Jiangdong Gong ◽  
Renjie Li ◽  
Hong Han ◽  
...  
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
High Sensitivity ◽  
Low Power Consumption ◽  
Memory Enhancement ◽  
Dendritic Integration ◽  
Artificial Synapse ◽  
Potential Applications

A conversion-type electrochemical artificial synapse exhibits potential applications for memory enhancement and dendritic integration; ultra-high sensitivity (3 mV) and extremely low-power consumption (32 fW) could be achieved.

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