scholarly journals Optical Angular Sensor for Space Applications

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5979
Author(s):  
Alexander Dabsch ◽  
Christoph Rosenberg ◽  
Majesa Trimmel ◽  
Franz Keplinger
Keyword(s):  
Rotation Angle ◽  
Coating Layer ◽  
Reference Signal ◽  
Multiple Reflections ◽  
Core Element ◽  
Space Applications ◽  
Optical Medium ◽  
Reflected Wave ◽  
Angle Measurements ◽  
Fresnel Equation

This paper describes a silicon/glass sensing structure for axial angle measurements. The presented optical angular sensor can statically measure the angle φ of any apparatus depending on the torsion of the optical component against the sensor housing. Core element of the sensor is an optical medium with an etched structure, which diffracts light from an LED according to the Fresnel equation. Two photodiodes, one for angle determination and one as reference, conduct the measurement. Hence, the signal splits up into two parts: one part transmits trough the optical system and the second part (the reflected wave) is used as reference signal. For self-referencing purposes, the wavelength spectrum of the LED has its maximum in the infrared regime near to the wavelength where silicon gets transparent (l~1000 nm). More precisely, torsion angle and light intensity show a dependency given by Tstot if a straight etching structure (refraction profile) is used. To avoid multiple reflections of light, a coating layer restricts the illuminated area in the optical medium. With this setting a resolution of 0.05-degree rotation angle has been achieved and by stacking the construction, the sensor can measure an angular range from 30° up to 270°.

Formulas Deduction to Key Parameters of Multi-Reflection in GPR Survey

2011 ◽  
Vol 243-249 ◽  
pp. 1483-1489
Author(s):  
Guo Qiang ◽  
Xiu Run Ge ◽  
Ai Lan Che
Keyword(s):  
Travel Time ◽  
Incident Wave ◽  
Multiple Reflections ◽  
Reflected Wave ◽  
First Case

The present paper is to analyses the key parameters of multi-reflection in GPR Survey. At first, it introduced the theory and methods for GPR result explanation. Then it proposed the necessity to work on multi-reflection analysis. For the complexity of multi-reflection, it emphatically worked on secondary reflection. According to the distinction of travel routes, the secondary reflection was divided into two cases. In the first case, the incident wave reflected twice at every interface and in the second case, the incident wave reflected for twice at every layer, meanwhile, the second reflected wave penetrated into the next layer as new incident wave. In these two cases, the amount of received waves was different and their corresponding transmitting parameters were deduced in the present paper. According to the deduction, in the situation of multiple reflections, the two-way travel time increases gradually; the energy decreases sharply and the profile curves are similar to each other.

Subsurface imaging using magnetotelluric data

Geophysics ◽  
1988 ◽  
Vol 53 (1) ◽  
pp. 104-117 ◽  
Author(s):  
S. Levv ◽  
D. Oldenburg ◽  
J. Wang
Keyword(s):  
Linear Programming ◽  
Impulse Response ◽  
Reference Signal ◽  
Impulse Response Function ◽  
Programming Approach ◽  
Reflection Seismology ◽  
Multiple Reflections ◽  
Magnetotelluric Data ◽  
Reflection And Transmission ◽  
Transmission Coefficients

A linear programming approach is developed to construct a pseudo‐impulse response for magnetotelluric (MT) data. The constructed time function is made up of discrete pulses whose amplitudes depend upon the electromagnetic reflection and transmission coefficients at various layer interfaces. The arrival time of an individual pulse corresponds to the time for a reference signal to travel a particular raypath from the surface to a reflector and back. The display of the impulse responses recovered from many stations produces an MT reflectivity section which is analogous to the image ray section regularly interpreted in reflection seismology. Application of linear programming inversion to one‐dimensional conductivity models shows the viability of the method and validates the physical interpretation of the pseudo‐impulse response function. Using a number of simple two‐dimensional geologic models, we show that a line of MT stations acquired perpendicular to strike produces a reflectivity section which is an image of the explored target. The interpretation of the MT image section follows the conventional guidelines used in reflection seismology; features such as traveltime pullup, primary and multiple reflections, and diffraction events are evident on the final section.

Novel Surface-Micromachined Micromirrors for Optical MEMS Beam Manipulators

2006 ◽  
Author(s):  
S. He ◽  
R. Ben Mrad
Keyword(s):  
High Performance ◽  
Rotation Angle ◽  
Layer Structure ◽  
Beam Steering ◽  
Repulsive Force ◽  
Driving Voltage ◽  
Optical Mems ◽  
Space Applications ◽  
Electrostatic Actuators ◽  
Large Rotation

A novel surface-micromachined electrostatic rotation micromirror is presented. The micromirror can be used to develop high performance optical beam steering manipulators for space applications based on an array of such micromirrors which are controlled by a feedback controller to compensate for jitter and misalignment during optical metrology or communication. The rotation micromirror has a two-layer structure and uses two repulsive force electrostatic actuators which generate a force to rotate the mirror out-of-plane. The rotation angle of the micromirror is not limited by the initial gap distance between the mirror plate and the substrate. By using repulsive force actuators, the surface-micromachined rotation micromirror can achieve a large rotation angle for a large mirror size without requiring any post-release assembly to fold the mirror out or raise it up. Prototypes fabricated using MUMPs are characterized by a mirror size of 312 μm × 312 μm, a stiffness of 0.485e−8Nm/rad, a mechanical rotation of 0° ∼ 2.2° at a driving voltage of 0 ∼ 200 V.

scholarly journals Mesoporous Silica SBA-15 Particles in a Detergent Solution as Abrasive and Coating Material for Household Care Cleaning Products

2019 ◽  
Vol 3 (1) ◽  
pp. 12
Author(s):  
Athanasios Plomaritis ◽  
Dimitris Giliopoulos ◽  
Konstantinos Triantafyllidis ◽  
Margaritis Kostoglou ◽  
Thodoris D. Karapantsios
Keyword(s):  
Mesoporous Silica ◽  
Coating Layer ◽  
Detergent Solution ◽  
Cleaning Process ◽  
Large Area ◽  
Wetting Properties ◽  
Left Behind ◽  
Angle Measurements ◽  
Cleaning Products ◽  
Contact Angle Measurements

Cleaning products have improved a lot in the last century. The reason for this improvement is not only the use of new surfactants, but also the use of additives that either increase the efficiency of surfactants or act as abrasive agents that increase the mechanical friction during the cleaning process. In this study mesoporous silica (SBA-15) particles are suggested as abrasive additives to a reference detergent as they have a quite soft structure and their shape can act as micro-sponge to collect large amounts of dirt. Indeed, SBA-15 performs very well when added to the detergent, decreasing the effort for primary cleaning of a surface. Furthermore, the properties of the coating layer left behind after primary cleaning with SBA-15 are also examined (i.e., secondary cleaning). It is found that SBA-15 offers no benefit for secondary cleaning. In order to explain this finding, the effect of SBA-15 on the wetting properties of different substrates is studied. It is seen that the SBA-15 coating layer is not uniform. Furthermore, it is seen that dirt is capable of pushing away the coating layer and occupying a large area on the substrate. Contact angle measurements indicate that the substrates become more omniphilic in the presence of SBA-15 coating.

Simultaneous Cotton-Mouton and Faraday rotation angle measurements on JET

2006 ◽  
Vol 77 (10) ◽  
pp. 10F324 ◽  
Author(s):  
A. Boboc ◽  
L. Zabeo ◽  
A. Murari ◽  
Keyword(s):  
Faraday Rotation ◽  
Rotation Angle ◽  
Angle Measurements ◽  
Faraday Rotation Angle

Structure and migration of planar defects in crystals observed in atomic scale

1978 ◽  
Vol 36 (1) ◽  
pp. 284-285 ◽  
Author(s):  
H. Hashimoto ◽  
Y. Sugimoto ◽  
Y. Takai ◽  
H. Endoh
Keyword(s):  
Electron Microscope ◽  
Rotation Angle ◽  
Crystal Surface ◽  
Electron Gun ◽  
Atomic Scale ◽  
Present Observation ◽  
Twist Boundary ◽  
Optical Magnification ◽  
Zinc Crystal ◽  
And Migration

As was demonstrated by the present authors that atomic structure of simple crystal can be photographed by the conventional 100 kV electron microscope adjusted at “aberration free focus (AFF)” condition. In order to operate the microscope at AFF condition effectively, highly stabilized electron beams with small energy spread and small beam divergence are necessary. In the present observation, a 120 kV electron microscope with LaB6 electron gun was used. The most of the images were taken with the direct electron optical magnification of 1.3 million times and then magnified photographically.1. Twist boundary of ZnSFig. 1 is the image of wurtzite single crystal with twist boundary grown on the surface of zinc crystal by the reaction of sulphur vapour of 1540 Torr at 500°C. Crystal surface is parallel to (00.1) plane and electron beam is incident along the axis normal to the crystal surface. In the twist boundary there is a dislocation net work between two perfect crystals with a certain rotation angle.

Musculoskeletal disorder risk associated with auto rotation angle during an assembly task

2009 ◽  
Author(s):  
Sue A. Ferguson ◽  
William S. Marras ◽  
W. Gary Allread ◽  
Gregory G. Knapik ◽  
Kimberly A. Vandlen ◽  
...  
Keyword(s):  
Musculoskeletal Disorder ◽  
Rotation Angle ◽  
Assembly Task ◽  
Disorder Risk

4D printing technology, modern era: A short review

2020 ◽  
pp. 92-111
Author(s):  
Khodadad Mostakim ◽  
Nahid Imtiaz Masuk ◽  
Md. Rakib Hasan ◽  
Md. Shafikul Islam
Keyword(s):  
Smart Materials ◽  
Computer Aided Design ◽  
Short Review ◽  
Stimuli Responsive ◽  
4D Printing ◽  
Space Applications ◽  
Printing Technology ◽  
Practical Applications ◽  
Biomedical Technologies ◽  
Novel Material

The advancement in 3D printing has led to the rapid growth of 4D printing technology. Adding time, as the fourth dimension, this technology ushered the potential of a massive evolution in fields of biomedical technologies, space applications, deployable structures, manufacturing industries, and so forth. This technology performs ingenious design, using smart materials to create advanced forms of the 3-D printed specimen. Improvements in Computer-aided design, additive manufacturing process, and material science engineering have ultimately favored the growth of 4-D printing innovation and revealed an effective method to gather complex 3-D structures. Contrast to all these developments, novel material is still a challenging sector. However, this short review illustrates the basic of 4D printing, summarizes the stimuli responsive materials properties, which have prominent role in the field of 4D technology. In addition, the practical applications are depicted and the potential prospect of this technology is put forward.

A method for measuring the in-plane compressive strength and the compression behavior of coating layers

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Coating Layer ◽  
Test Methods ◽  
Coating Films ◽  
Precipitated Calcium Carbonate ◽  
Coating Color ◽  
Mineral Coatings ◽  
Styrene Butadiene

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.

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