Effect of beam length on the uncooled microbolometer performance

2021 ◽  
Author(s):  
Ashudeep Minhas ◽  
Deepak Bansal
Keyword(s):  
Beam Length ◽  
Uncooled Microbolometer

Improved Autoadhesion Measurement Method for Micromachined Polysilicon Beams

1996 ◽  
Vol 444 ◽  
Author(s):  
Maarten P. de Boer ◽  
Terry A. Michalske
Keyword(s):  
Surface Chemistry ◽  
Optical Microscopy ◽  
Measurement Method ◽  
Current Practice ◽  
Cantilever Beams ◽  
Beam Length ◽  
Substrate Adhesion

AbstractWe have measured autoadhesion (e.g. stiction) of individual polysilicon beams by interferometric optical microscopy. Untreated cantilever beams were dried from water in air, while treated beams were coated with a hydrophobic molecular coating of octadecyltrichlorosilane (ODTS). Adhesion values obtained for beams adhered to the substrate over a long length (large d) are independent of beam length with values of 16.7 and 4.4 mJ/m2 for untreated and treated samples respectively. These values can be understood in terms of differences in surface chemistry and polysilicon roughness. Using the shortest length beam which remains attached to the substrate, adhesion values were 280 and 16 mJ/m2 respectively. These higher values may be a result of capillarity effects. We recommend that measurements be made on beams in which d is large, in contrast to the current practice of noting the shortest beam adhered.

Uncooled microbolometer mosaic focal plane arrays for the infrared and terahertz ranges

2016 ◽  
Vol 52 (2) ◽  
pp. 203-209
Author(s):  
M. A. Dem’yanenko ◽  
A. I. Kozlov ◽  
A. R. Novoselov ◽  
V. N. Ovsyuk
Keyword(s):  
Focal Plane ◽  
Focal Plane Arrays ◽  
Uncooled Microbolometer

scholarly journals An Electrostatic Self-Excited Resonator with Pre-Tension/Pre-Compression Constraint for Active Rotation Control

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 650
Author(s):  
Ruide Yun ◽  
Yangsheng Zhu ◽  
Zhiwei Liu ◽  
Jianmei Huang ◽  
Xiaojun Yan ◽  
...  
Keyword(s):  
Maximum Velocity ◽  
Flapping Wings ◽  
Variable Velocity ◽  
Beam Length ◽  
Dc Voltage ◽  
Middle Position ◽  
Simply Supported ◽  
Maximum Value ◽  
Constraint Structure

We report a novel electrostatic self-excited resonator driven by DC voltage that achieves variable velocity-position characteristics via applying the pre-tension/pre-compression constraint. The resonator consists of a simply supported micro-beam, two plate electrodes, and two adjustable constraint bases, and it can be under pre-compression or pre-tension constraint by adjusting the distance L between two constraint bases (when beam length l > L, the resonator is under pre-compression and when l < L, it is under pre-tension). The oscillating velocity of the beam reaches the maximum value in the position around electrodes under the pre-compression constraint and reaches the maximum value in the middle position between two electrodes under the pre-tension condition. By changing the constraint of the microbeam, the position of the maximum velocity output of the oscillating beam can be controlled. The electrostatic self-excited resonator with a simple constraint structure under DC voltage has great potential in the field of propulsion of micro-robots, such as active rotation control of flapping wings.

scholarly journals An Ultrahigh-Sensitivity Graphene Resonant Gyroscope

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1890
Author(s):  
Yang Lu ◽  
Zhan-She Guo ◽  
Shang-Chun Fan
Keyword(s):  
Angular Velocity ◽  
High Sensitivity ◽  
Velocity Variation ◽  
Beam Length ◽  
Sensing Element ◽  
Finite Element Software ◽  
Resonant Beam ◽  
Frequency Output ◽  
Length Width ◽  
Ultrahigh Sensitivity

In this study, a graphene beam was selected as a sensing element and used to form a graphene resonant gyroscope structure with direct frequency output and ultrahigh sensitivity. The structure of the graphene resonator gyroscope was simulated using the ANSYS finite element software, and the influence of the length, width, and thickness of the graphene resonant beam on the angular velocity sensitivity was studied. The simulation results show that the resonant frequency of the graphene resonant beam decreased with increasing the beam length and thickness, while the width had a negligible effect. The fundamental frequency of the designed graphene resonator gyroscope was more than 20 MHz, and the sensitivity of the angular velocity was able to reach 22,990 Hz/°/h. This work is of great significance for applications in environments that require high sensitivity to extremely weak angular velocity variation.

scholarly journals Estimation of the minimum beam length for the static, dynamic, and stability problems

2021 ◽  
Vol 1155 (1) ◽  
pp. 012101
Author(s):  
A E Mityaev ◽  
I V Kudryavtsev ◽  
M P Khomutov ◽  
M V Brungardt ◽  
A V Kolotov
Keyword(s):  
Beam Length ◽  
Stability Problems

scholarly journals Dynamic Analysis of Honeycomb Sandwich Beam with Multiple Debonds

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
B. Saraswathy ◽  
R. Ramesh Kumar ◽  
Lalu Mangal
Keyword(s):  
Analytical Solution ◽  
Transient Analysis ◽  
Sandwich Beam ◽  
Beam Theory ◽  
Beam Length ◽  
Honeycomb Core ◽  
Element Analysis ◽  
Fast Fourier Transform Analysis ◽  
Honeycomb Sandwich ◽  
Nonlinear Transient

Analytical formulation for the evaluation of frequency of CFRP sandwich beam with debond, following the split beam theory, generally underestimates the stiffness, as the contact between the honeycomb core and the skin during vibration is not considered in the region of debond. The validation of the present analytical solution for multiple-debond size is established through 3D finite element analysis, wherein geometry of honeycomb core is modeled as it is, with contact element introduced in the debond region. Nonlinear transient analysis is followed by fast Fourier transform analysis to obtain the frequency response functions. Frequencies are obtained for two types of model having single debond and double debond, at different spacing between them, with debond size up to 40% of beam length. The analytical solution is validated for a debond length of 15% of the beam length, and with the presence of two debonds of same size, the reduction in frequency with respect to that of an intact beam is the same as that of a single-debond case, when the debonds are well separated by three times the size of debond. It is also observed that a single long debond can result in significant reduction in the frequencies of the beam than multiple debond of comparable length.

Consistent Hydrodynamic Mass for Parallel Prismatic Beams in a Fluid-Filled Container

1984 ◽  
Vol 106 (3) ◽  
pp. 270-275
Author(s):  
J. F. Loeber
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Incompressible Fluid ◽  
Finite Element Methods ◽  
Mass Matrix ◽  
Three Dimensional ◽  
Beam Length ◽  
Step Process ◽  
Beam Bending

In this paper, representation of the effects of incompressible fluid on the dynamic response of parallel beams in fluid-filled containers is developed using the concept of hydrodynamic mass. Using a two-step process, first the hydrodynamic mass matrix per unit (beam) length is derived using finite element methods with a thermal analogy. Second, this mass matrix is distributed in a consistent mass fashion along the beam lengths in a manner that accommodates three-dimensional beam bending plus torsion. The technique is illustrated by application to analysis of an experiment involving vibration of an array of four tubes in a fluid-filled cylinder.

Effect of Hub Radius on the Vibrations of a Uniform Bar

1956 ◽  
Vol 23 (2) ◽  
pp. 287-290
Author(s):  
W. E. Boyce
Keyword(s):  
Lower Bounds ◽  
Constant Speed ◽  
Upper And Lower Bounds ◽  
Beam Length ◽  
Uniform Beam

Abstract Methods are discussed for obtaining upper and lower bounds on the frequencies of a uniform beam, rotating at a constant speed about an axis at one end, and vibrating transversely to the plane of rotation. Previous results are extended to include the case of a nonzero hub radius. Bounds on the first two frequencies are given for several ratios of hub radius to beam length. These show that the frequencies depend almost linearly on the hub radius for various rotational speeds.

scholarly journals PENGARUH PANJANG BENTANG TERHADAP UKURAN PENAMPANG OPTIMUM BETON PRATEGANG PADA BALOK SEDERHANA DENGAN MENGGUNAKAN ALGORITMA GENETIKA

2018 ◽  
Vol 7 (1) ◽  
pp. 16-25
Author(s):  
Alfian Wiranata Zebua
Keyword(s):  
Optimum Design ◽  
Low Cost ◽  
Optimization Procedure ◽  
Service Condition ◽  
Beam Width ◽  
Beam Length ◽  
Limit Values ◽  
Optimization Result ◽  
Prestressing Force ◽  
Fitness Value

Abstract: Structural design philosophy expected to be low cost and safe at once. At prestressed concrete structure, concrete allowable stress for bending structural component have to fullfill limit values on tranfer and service condition. Prestressed force determined using moment coeffiecient β method based on allwoable stress. At this structure, to achieve optimum design is not an easy task due to interaction between dimension size and prestressing force value. To determine optimum design criteria, genetics algorithms as one of optimum design method has been used in this paper. Genetics algorithm is a method to find the best solution using organism genetics process based on Darwin theory which solutions with the best fitness value that could be survive as the optimization result. Fitness value is minimum construction cost. Optimization process using genetics algorithm has been worked with computer software assitance Matlab. Simpe beam has been considered as numerical example. Optimization result is optimum design of dimension size and prestressing force. Optimization procedure with beam length (L) 10 m result are beam width (b) 0,40 m, beam height (h) 0,47 m, prestressing force (Fi) value 1344 KN and bulding cost total Rp. 16.651.000,-. Next optimization procedure has been done using different beam length. From this study, the interaction between beam length to optimum dimension size and minimum building cost has been achieved.Keywords : beam length, genetics algoritm, optimum sizing, prestressed concreteAbstrak: Filosofi perencanaan struktur diharapkan ekonomis sekaligus aman. Pada struktur beton prategang, tegangan ijin beton untuk komponen struktur lentur harus memenuhi nilai batas pada saat transfer dan beban layan. Gaya prategang ditentukan dengan menggunakan metode koefisien momen β yang didasarkan pada tegangan ijin. Pada struktur ini, penentuan desain optimum tidak mudah karena adanya keterkaitan antara ukuran penampang dengan besaran gaya prategang yang dibutuhkan. Untuk memperoleh kriteria desain yang optimum digunakan metode optimasi dengan menggunakan algoritma genetika. Algoritma genetika merupakan metode pencarian sesuai dengan proses genetika  organisme berdasarkan teori evolusi Darwin, dimana solusi dengan nilai fitness (tujuan) yang tinggi yang mampu bertahan sebagai hasil dari proses optimasi. Nilai fitness (tujuan) adalah memperoleh total harga konstruksi yang paling rendah. Proses optimasi dengan algoritma genetika dikerjakan dengan bantuan software komputer Matlab. Untuk melakukan optimasi digunakan algoritma genetika real. Jenis struktur yang ditinjau adalah balok sederhana. Dari hasil optimasi dengan berbagai panjang bentang diperoleh dimensi balok dan nilai gaya prategang yang optimum. Proses optimasi dengan panjang bentang (L) 10 m, diperoleh lebar balok (b) 0,40 m,  tinggi balok (h) 0,47 m, nilai gaya prategang (Fi) sebesar 1344 KN dengan total harga Rp. 16.651.000,-. Proses optimasi selanjutnya dilakukan dengan panjang bentang balok yang bervariasi. Dari hasil penelitian diperoleh hubungan antara panjang bentang balok dengan ukuran penampang optimum serta harga total struktur yang paling rendah.Kata kunci : algoritma genetika, beton prategang, panjang bentang, ukuran penampang optimum

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