scholarly journals In-Line Analysis of Diffusion Processes in Micro Channels by Long Distance Raman Photometric Measurement Technology—A Proof of Concept Study

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 116
Author(s):  
Julian Deuerling ◽  
Shaun Keck ◽  
Inasya Moelyadi ◽  
Jens-Uwe Repke ◽  
Matthias Rädle
Keyword(s):  
Numerical Aperture ◽  
Spot Size ◽  
Measuring System ◽  
Optical Systems ◽  
Measurement Technology ◽  
Long Distance ◽  
Measuring Point ◽  
Acetone Concentration ◽  
Micro Channels ◽  
Set Up

This work presents a novel method for the non-invasive, in-line monitoring of mixing processes in microchannels using the Raman photometric technique. The measuring set-up distinguishes itself from other works in this field by utilizing recent state-of-the-art customized photon multiplier (CPM) detectors, bypassing the use of a spectrometer. This addresses the limiting factor of integration times by achieving measuring rates of 10 ms. The method was validated using the ternary system of toluene–water–acetone. The optical measuring system consists of two functional units: the coaxial Raman probe optimized for excitation at a laser wavelength of 532 nm and the photometric detector centered around the CPMs. The spot size of the focused laser is a defining factor of the spatial resolution of the set-up. The depth of focus is measured at approx. 85 µm with a spot size of approx. 45 µm, while still maintaining a relatively high numerical aperture of 0.42, the latter of which is also critical for coaxial detection of inelastically scattered photons. The working distance in this set-up is 20 mm. The microchannel is a T-junction mixer with a square cross section of 500 by 500 µm, a hydraulic diameter of 500 µm and 70 mm channel length. The extraction of acetone from toluene into water is tracked at an initial concentration of 25% as a function of flow rate and accordingly residence time. The investigated flow rates ranged from 0.1 mL/min to 0.006 mL/min. The residence times from the T-junction to the measuring point varies from 1.5 to 25 s. At 0.006 mL/min a constant acetone concentration of approx. 12.6% was measured, indicating that the mixing process reached the equilibrium of the system at approx. 12.5%. For prototype benchmarking, comparative measurements were carried out with a commercially available Raman spectrometer (RXN1, Kaiser Optical Systems, Ann Arbor, MI, USA). Count rates of the spectrophotometer surpassed those of the spectrometer by at least one order of magnitude at identical target concentrations and optical power output. The experimental data demonstrate the suitability and potential of the new measuring system to detect locally and time-resolved concentration profiles in moving fluids while avoiding external influence.

scholarly journals Photonic crystal fiber metalens

Nanophotonics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 443-449 ◽  
Author(s):  
Jingyi Yang ◽  
Indra Ghimire ◽  
Pin Chieh Wu ◽  
Sudip Gurung ◽  
Catherine Arndt ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Optical Fiber ◽  
Numerical Aperture ◽  
Spot Size ◽  
Long Distance ◽  
Silica Glasses ◽  
Crystal Fiber ◽  
Novel Technology ◽  
Fiber Materials ◽  
Novel Applications

AbstractConventional optical fiber has excellent performance in guiding light, which has been widely employed for long-distance optical communication. Although the optical fiber is efficient for transmitting light, its functionality is limited by the dielectric properties of the core’s and cladding’s materials (e.g. Ge-doped-silica and silica glasses). The spot size of the transmitted light is diverging and restricted by the diffraction limit of the dielectric core, and the numerical aperture is determined by the refractive index of the fiber materials. However, the novel technology of metasurfaces is opening the door to a variety of optical fiber innovations. Here, we report an ultrathin optical metalens directly patterned on the facet of a photonic crystal optical fiber that enables light focusing in the telecommunication regime. In-fiber metalenses with focal lengths of 28 μm and 40 μm at a wavelength of 1550 nm are demonstrated with maximum enhanced optical intensity as large as 234%. The ultrathin optical fiber metalens may find novel applications in optical imaging, sensing, and fiber laser designs.

scholarly journals Long-Distance Sub-Diffraction High-Resolution Imaging Using Sparse Sampling

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3116
Author(s):  
Duo Wang ◽  
Tianjiao Fu ◽  
Guoling Bi ◽  
Longxu Jin ◽  
Xingxiang Zhang
Keyword(s):  
High Resolution ◽  
Reconstruction Algorithm ◽  
Optical Systems ◽  
Measurement Technology ◽  
High Resolution Imaging ◽  
Low Resolution ◽  
Long Distance ◽  
Microscopic Imaging ◽  
Resolution Imaging ◽  
Low Resolution Images

How to perform imaging beyond the diffraction limit has always been an essential subject for the research of optical systems. One effective way to achieve this purpose is Fourier ptychography, which has been widely used in microscopic imaging. However, microscopic imaging measurement technology cannot be directly extended to imaging macro objects at long distances. In this paper, a reconstruction algorithm is proposed to solve the need for oversampling low-resolution images, and it is successfully applied to macroscopic imaging. Compared with the traditional FP technology, the proposed sub-sampling method can significantly reduce the number of iterations in reconstruction. Experiments prove that the proposed method can reconstruct low-resolution images captured by the camera and achieve high-resolution imaging of long-range macroscopic objects.

Microspectroscopy Using a Solid Immersion Lens

2001 ◽  
Vol 7 (S2) ◽  
pp. 148-149
Author(s):  
C.D. Poweleit ◽  
J Menéndez
Keyword(s):  
Spatial Resolution ◽  
Focal Plane ◽  
Numerical Aperture ◽  
Normal Incidence ◽  
Spot Size ◽  
Index Of Refraction ◽  
Objective Lens ◽  
Improvement Factor ◽  
Oil Immersion ◽  
Long Time

Oil immersion lenses have been used in optical microscopy for a long time. The light’s wavelength is decreased by the oil’s index of refraction n and this reduces the minimum spot size. Additionally, the oil medium allows a larger collection angle, thereby increasing the numerical aperture. The SIL is based on the same principle, but offers more flexibility because the higher index material is solid. in particular, SILs can be deployed in cryogenic environments. Using a hemispherical glass the spatial resolution is improved by a factor n with respect to the resolution obtained with the microscope’s objective lens alone. The improvement factor is equal to n2 for truncated spheres.As shown in Fig. 1, the hemisphere SIL is in contact with the sample and does not affect the position of the focal plane. The focused rays from the objective strike the lens at normal incidence, so that no refraction takes place.

scholarly journals Ultrawide-angle and high-efficiency metalens in hexagonal arrangement

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chun-Yuan Fan ◽  
Chia-Ping Lin ◽  
Guo-Dung J. Su
Keyword(s):  
High Efficiency ◽  
Numerical Aperture ◽  
Vital Role ◽  
Optical Systems ◽  
Wide Field ◽  
Wide Angle ◽  
Camera Systems ◽  
Single Lens ◽  
Hexagonal Arrangement ◽  
Virtual And Augmented Reality

Abstract Wide-angle optical systems play a vital role in imaging applications and have been researched for many years. In traditional lenses, attaining a wide field of view (FOV) by using a single optical component is difficult because these lenses have crucial aberrations. In this study, we developed a wide-angle metalens with a numerical aperture of 0.25 that provided a diffraction-limited FOV of over 170° for a wavelength of 532 nm without the need for image stitching or multiple lenses. The designed wide-angle metalens is free of aberration and polarization, and its full width of half maximum is close to the diffraction limit at all angles. Moreover, the metalens which is designed through a hexagonal arrangement exhibits higher focusing efficiency at all angles than most-seen square arrangement. The focusing efficiencies are as high as 82% at a normal incident and 45% at an incident of 85°. Compared with traditional optical components, the proposed metalens exhibits higher FOV and provides a more satisfactory image quality because of aberration correction. Because of the advantages of the proposed metalens, which are difficult to achieve for a traditional single lens, it has the potential to be applied in camera systems and virtual and augmented reality.

scholarly journals Study of Optical Fiber Design Parameters in Fiber Optics Communications

2017 ◽  
Vol 2 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Salim Qadir Mohammed ◽  
Asaad M. Asaad M. Al-Hindawi
Keyword(s):  
Optical Fiber ◽  
Fiber Optics ◽  
Numerical Aperture ◽  
Design Parameters ◽  
Light Sources ◽  
Long Distance ◽  
Graded Index ◽  
Large Bandwidth ◽  
Telecommunication Infrastructure ◽  
Distance Communication

Fiber optics is an important part in the telecommunication infrastructure. Large bandwidth and low attenuation are features for the fiber optics to provide gigabit transmission. Nowadays, fiber optics are used widely in long distance communication and networking to provide the required information traffic for multimedia applications. In this paper, the optical fiber structure and the operation mechanism for multimode and single modes are analyzed. The design parameters such as core radius, numerical aperture, attenuation, dispersion and information capacity for step index and graded index fibers are studied, calculated and compared for different light sources.

scholarly journals Gamma spectrometry technique for the determination of residence time in Submarine Groundwater Discharges

2019 ◽  
Vol 18 ◽  
pp. 155
Author(s):  
G. Eleftheriou ◽  
C. Tsabaris ◽  
D. L. Patiris ◽  
E. Androulakaki ◽  
M. Kokkoris ◽  
...  
Keyword(s):  
Residence Time ◽  
Water Samples ◽  
Gamma Ray ◽  
Measuring System ◽  
Gamma Ray Spectrometry ◽  
Reference Source ◽  
Radium Isotopes ◽  
Time Period ◽  
Submarine Groundwater ◽  
Set Up

The evaluation of time period that meteoric water remains in the ground (residence time) before exiting in the open sea can be a valuable information for the submarine groundwater discharges (SGD) in the costal zones. Coastal waters contain elevated dissolved activities of radium isotopes compared to the open ocean, where excess activities are zero. Lately it has been shown by Moore et al., that residence time can be estimated by a model based on radium radioisotopes ratio reduction throughout the coast. However the standard methods for the estimation of radium isotopes concentration in the water are sophisticated, time consuming or require big amount of sample. Hereby, a method based on the direct gamma ray spectrometry of untreated water samples from coastal areas is applied to determine the residence time of the SGD. Efficiency calibration of the spectrometry set up has been performed for two different volumetric sample geometries, using 152Eu/154Eu solution as reference source. In order to ensure the reliability of the method, the background courting rate magnitude and variance through time have been defined for the radioisotopes of interest. Additionally, the minimum detectible activity (MDA) of the measuring system was determined, in Becquerel per cubic meter, as a function of energy in water samples. The developed method was applied and validated for water samples from the submarine spring in Stoupa Bay, southwestern Peloponnesus. The defined residence time varies from 3 to 6 days, being in good agreement with the results of the standard geological pigment-tracer method.

scholarly journals FREON COOLING MINISYSTEM USING CIRCULAR MICRO-CHANNELS

2017 ◽  
Vol 20 (2) ◽  
Author(s):  
LILIANA PĂTULEANU ◽  
IOAN-COZMIN MANOLACHE-RUSU ◽  
TIBERIU BURDAN ◽  
FLORIN ANDRONIC ◽  
IVAN RADION
Keyword(s):  
Processing Speed ◽  
Heat Exchangers ◽  
Mechanical Compression ◽  
Refrigeration System ◽  
Electronic Components ◽  
Local Cooling ◽  
New Methods ◽  
Micro Channels ◽  
Nano Channel ◽  
Set Up

<p>The necessity of a higher data processing speed was crucial for the advances in computer science. There were created processors that needed increasingly more power, so that new methods were discovered and more complex systems were created in order to solve the cooling issue. In this paper, there are presented the trials performed on a mini refrigeration plant that used mechanical compression of Freon’s, designed to cool electronic components like microprocessors, microcontrollers, graphic stations, or in the case of local cooling in diverse areas such as bioengineering, optics and nanotechnologies. The refrigeration system was constructed as an experimental set-up and consists of the following: two mini heat exchangers, working both as a condenser and a vaporizer, which are made of circular micro channels, a refrigeration compressor, lamination valve which contains a circular nano channel and a micro filter. The experimental determinations have proven that, although such a system contains a small quantity of Freon, of the order of milligrams, it reaches temperatures of -44 °C.</p>

Colonization of depopulated crinoids by symbionts: who comes from the bottom and who from the water column?

2015 ◽  
Vol 95 (8) ◽  
pp. 1607-1612 ◽  
Author(s):  
E.S. Mekhova ◽  
P.Y. Dgebuadze ◽  
V.N. Mikheev ◽  
T.A. Britayev
Keyword(s):  
Water Column ◽  
Field Experiments ◽  
Dispersal Ability ◽  
Long Distance ◽  
Sandy Substrate ◽  
Limited Dispersal ◽  
Set Up ◽  
Almost All ◽  
High Degree

Previous experiments with the comatulid Himerometra robustipinna (Carpenter, 1881) demonstrated intensive host-to-host migration processes for almost all symbiotic species both within host aggregations and among hosts separated by several metres. The aim of this study was to check the ability of symbionts to complete long-distance migrations, by means of two in situ experiments which depopulated the crinoid host. Two different sets of field experiments were set up: exposure of depopulated crinoids (set 1) on stony ‘islands’ isolated from native crinoid assemblages by sandy substrate, and (set 2) in cages suspended in the water column. Hosts from set 1 were exposed for 1, 2, 3 and 4 weeks to assess whether substrate has an influence on the symbionts' long-distance migrations. In set 2 cages were exposed for 10–11 days, aiming to check whether symbionts were able to disperse through the water column with currents. These experiments allow the conclusion that post-settled symbionts can actively migrate among their hosts. Symbionts are able to reach their hosts by employing two different ‘transport corridors’, by drifting or swimming in water column, and by moving on the bottom. Comparison of experimental results allows the division of symbionts into two conventional groups according to the dispersal ability of their post-settled stages: (1) species able to complete long-distance migrations, (2) species unable to migrate or having limited dispersal ability. The finding of the free-living shrimp Periclimenes diversipes Kemp, 1922 in set 2 raises the question about the factors that affect such a high degree of specialization of crinoid assemblages.

Algorithm for Detecting Multiple Partial Blockages in Liquid Pipelines by Using Inverse Transient Analysis

SPE Journal ◽  
2021 ◽  
pp. 1-29
Author(s):  
C. Zhang ◽  
J. J. Zhang ◽  
C. B. Ma ◽  
G. E. Korobkov
Keyword(s):  
Inverse Problem ◽  
Crude Oil ◽  
Direct Problem ◽  
Pressure Response ◽  
Analytical Evaluation ◽  
Long Distance ◽  
Local Flow ◽  
Measuring Point ◽  
Detection Techniques ◽  
Oil Pipelines

Summary Partial blockages form on the inner wall of the crude-oil pipelines as a result of asphaltene precipitation, scale deposition, and so forth. If not controlled and rehabilitated periodically, these partial blockages can have a serious adverse effect on the efficiency, economy, and safety of the operation of the pipeline. Before each rehabilitation operation, the detection of the local flow-condition deterioration (change in diameter) is necessary for efficiency and economy considerations, especially for long-distance subsea crude-oil pipelines. Most conventional detection techniques require the installment of detecting devices along the pipeline. However, they are economically expensive and even technically impossible for pipelines in operation. The present work focuses on an economically efficient technique that can realize remote nonintrusive measurement (i.e., the pressure-wave technique). The purpose of our research is to develop a method for calibrating multiple irregular partial blockages inside the liquid pipe by using the pressure response in the time domain at certain measuring points along the pipe under the transient state. The method involves the direct problem and the inverse problem. The direct problem is the simulation of the transient flow in the liquid pipe with single or multiple partial blockages. A second-order direct problem solver is developed in the framework of the Godunov-typefinite-volume method (FVM). The inverse problem is to determine the partial-blockage distribution by using the pressure response at the measuring point under transient conditions. Our algorithm to solve the inverse problem comprises analytical evaluation and optimization. The analytical evaluation provides a reliable search space for the following optimization procedure, and thus effectively alleviates the local optimum problem. Numerical results demonstrate the efficiency and accuracy of proposed methods for solving the direct and inverse problems.

Experimental Study of the Temperature Field Equation in the Leeward Tunnel during Mine Fire Period

2012 ◽  
Vol 588-589 ◽  
pp. 1842-1848
Author(s):  
Wen Cai Wang ◽  
Yu Hong Jiang ◽  
Tao Hou ◽  
Wei Liu ◽  
Yang Lu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Temperature Field ◽  
Field Equation ◽  
Wind Speed ◽  
Stable Phase ◽  
Measuring Point ◽  
Mine Fire ◽  
Mine Roadway ◽  
Set Up

According to the principle of heat transfer, the temperature field equation in the leeward tunnel was set up and the experimental device with a ratio of 1:20 was built. When it happened to fire in roadway, the correctness of the temperature field equation can be verified by the experiment. In experiments, the armored thermocouple and color paperless recorder were used to record the temperature of each measuring point. The S-3-300 pitot tube and YJB-2500 compensation micro-manometer were used to determine the wind speed. When the mine roadway fired, the experiment determined the temperature field equation experiment coefficient of Kc. It showed that in the developing phase of the fire Kc= 15 ~ 20, in the stable phase of the fire Kc= 10 ~ 15, in the failing phase of the fire Kc= 20 ~ 25.

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