scholarly journals Analysis of the Transverse Force in the Rayleigh and Mie Approximations for a Capture Beam TEM00 and TEM*01

Respuestas ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 53-59
Author(s):  
Darby Páez - Amaya ◽  
Frederic Català - Castro ◽  
Martha Lucia Molina - Prado ◽  
Mario Montes-Usategui ◽  
Néstor Alonso Arias - Hernández
Keyword(s):  
Optical Tweezers ◽  
Current Problem ◽  
State Of The Art ◽  
Force Measurement ◽  
Radiation Force ◽  
Dielectric Sphere ◽  
Mathematical Expressions ◽  
Art Research ◽  
Theoretical Results ◽  
A Current

Optical tweezers use a highly-focused laser beam to capture and manipulate micro- and nanometric objects. These have been demonstrated to be a promising devices for state-of-the-art research in several fields, such as microbiology and biophysics. The prediction of the optical forces that are present in this phenomenon is a current problem in continuous evolution. Additionally, the recent use of vortex beams with exotic properties as the orbital angular momentum, with advantages as the rotational manipulation of the captured microparticles and reduction of the optical damage in biological samples (Opticution), makes the problem even more complex.  Mathematical expressions in the Rayleigh and Mie regimes for the radiation force on a dielectric sphere captured by TEM00 and TEM*01 mode beams are presented. Theoretical results are then compared with experimental measurements obtained with a direct force measurement device based on light-momentum detection.

scholarly journals Parametrical synthesis of radio devices with the set quantity of unequal cascades for variants of inclusion of jet two-port networks between a nonlinear part and loading

2021 ◽  
Vol 24 (3) ◽  
pp. 63-70
Author(s):  
Aleksandr A. Golovkov ◽  
Vladimir A. Golovkov ◽  
Aleksey V. Fomin
Keyword(s):  
Comparative Analysis ◽  
Mathematical Modelling ◽  
Circuit Simulation ◽  
Algebraic Equations ◽  
Nonlinear Part ◽  
Substantial Growth ◽  
Mathematical Expressions ◽  
Definition Of ◽  
Theoretical Results ◽  
A Current

The algorithm of parametrical synthesis of various radio devices with any quantity of cascades of type a nonlinear part the jet two-port network by criterion of maintenance of the set frequency characteristics is developed. Nonlinear parts are presented in the form of a nonlinear element and parallel either consecutive on a current or pressure of a feedback. According to this criterion systems of the algebraic equations are generated and solved. Models of optimum two-port networks of one of cascades in the form of mathematical expressions for definition of interrelations between elements of their classical matrix of transfer and for search of dependences of resistance of two-poles from frequency are as a result received. It is spent mathematical and circuit simulation of the two-cascade amplifier. It is shown, that the increase in quantity of cascades with the optimised parametres leads to substantial growth of a working strip of frequencies. The comparative analysis of the theoretical results received by mathematical modelling in system MathCad, and the experimental results received by circuit simulation in systems OrCad and MicroCap, shows their satisfactory coincidence.

scholarly journals Parametrical synthesis of radio devices with the set quantity of identical cascades for variants of inclusion of jet two-port networks between a source of a signal and a nonlinear part

2021 ◽  
Vol 24 (3) ◽  
pp. 46-55
Author(s):  
Aleksandr A. Golovkov ◽  
Aleksey V. Fomin
Keyword(s):  
Comparative Analysis ◽  
Mathematical Modelling ◽  
Circuit Simulation ◽  
Frequency Characteristics ◽  
Algebraic Equations ◽  
Nonlinear Part ◽  
Mathematical Expressions ◽  
Definition Of ◽  
Theoretical Results ◽  
A Current

The algorithm of parametrical synthesis of various radio devices with any quantity of cascades of type the jet two-port network a nonlinear part by criterion of maintenance of the set frequency characteristics is developed. Nonlinear parts are presented in the form of a nonlinear element and parallel either consecutive on a current or pressure of a feedback. According to this criterion systems of the algebraic equations are generated and solved. Models of optimum two-port networks in the form of mathematical expressions for definition of interrelations between elements of their classical matrix of transfer and for search of dependences of resistance of two-poles from frequency are as a result received. It is shown, that frequency characteristics of investigated radio devices from identical cascades are identical or similar to frequency characteristics of radio devices from one cascade, but with resistance of a source of a signal and the loading, changed definitely. Such schemes are named by equivalent. The comparative analysis of the theoretical results received by mathematical modelling in system MathCad, and the experimental results received by circuit simulation in systems OrCad and MicroCap, shows their satisfactory coincidence.

scholarly journals Water-Worked Gravel Bed: State-of-the-Art Review

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 694 ◽  
Author(s):  
Ellora Padhi ◽  
Subhasish Dey ◽  
Venkappayya R. Desai ◽  
Nadia Penna ◽  
Roberto Gaudio
Keyword(s):  
State Of The Art ◽  
Flow Characteristics ◽  
Streamwise Velocity ◽  
Secondary Currents ◽  
Gravel Bed ◽  
Natural Stream ◽  
Art Research ◽  
The Comparative Study ◽  
Water Work

In a natural gravel-bed stream, the bed that has an organized roughness structure created by the streamflow is called the water-worked gravel bed (WGB). Such a bed is entirely different from that created in a laboratory by depositing and spreading gravels in the experimental flume, called the screeded gravel bed (SGB). In this paper, a review on the state-of-the-art research on WGBs is presented, highlighting the role of water-work in determining the bed topographical structures and the turbulence characteristics in the flow. In doing so, various methods used to analyze the bed topographical structures are described. Besides, the effects of the water-work on the turbulent flow characteristics, such as streamwise velocity, Reynolds and form-induced stresses, conditional turbulent events and secondary currents in WGBs are discussed. Further, the results form WGBs and SGBs are compared critically. The comparative study infers that a WGB exhibits a higher roughness than an SGB. Consequently, the former has a higher magnitude of turbulence parameters than the latter. Finally, as a future scope of research, laboratory experiments should be conducted in WGBs rather than in SGBs to have an appropriate representation of the flow field close to a natural stream.

scholarly journals FRI0431 PROFILE OF INFECTIOUS SPONDYLODISCITIS ACCORDING TO THE SITE: UNIFOCAL VERSUS MULTIFOCAL

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 814.3-814
Author(s):  
A. Ben Tekaya ◽  
L. Ben Ammar ◽  
M. Ben Hammamia ◽  
O. Saidane ◽  
S. Bouden ◽  
...  
Keyword(s):  
Current Problem ◽  
Common Factor ◽  
Cord Compression ◽  
Posterior Arch ◽  
Significant Difference ◽  
Infectious Spondylodiscitis ◽  
Vertebral Biopsy ◽  
Inflammatory Syndrome ◽  
Different Levels ◽  
A Current

Background:Infectious spondylodiscitis is a therapeutic emergency and is a current problem. It can affect the different levels of the spine. Multifocal forms, touching several floors, however remain rare.Objectives:To compare the clinical, biological, radiological and therapeutic aspects of unifocal versus multifocal spondylodiscitis.Methods:This is a retrospective study of 113 patients admitted to our service over a period of 20 years [1998-2018]. The diagnosis of spondylodiscitis was made on the basis of clinical, biological, radiological and bacteriological data. We have divided our population into two groups: unifocal and multifocal spondylodiscitis.Results:Spondylodiscitis was more frequently unifocal (75.2%) than multifocal (24.8%). The average age of the patients was 55.8 years. There were 62 men and 51 women. There was no difference in age and sex between the two groups (p=0.5 and p=0.8, respectively).Diabetes was more frequent in the group of multifocal spondylodiscitis but with no statistically significant difference (p=0.4). No statistically significant difference between the two groups regarding the start mode (p=0.7), the schedule (p=0.3), the presence of neurological signs (p=0.7), fever (p = 0.2), impaired general condition (p=0.6) and biological inflammatory syndrome (p=0.6).Cervical and dorsal spine involvement was more common in multifocal spondylodiscitis (p = 0.02 and p = 0.01; respectively). There were 11 spondylodiscitis involving 2 floors (cervical and dorsal: 2 cases, cervical and lumbar: 3 cases, dorsal and lumbar: 6 cases) and 3 spondylodiscitis involving 3 floors.Radiologically, the presence of vertebral fracture and involvement of the posterior arch was more frequent during the multifocal form (p=0.03 and p=0.001; respectively). The frequency of para-vertebral abscesses, epiduritis and the presence of spinal cord compression were similar in the two groups (p=0.6; p=0.7 and p=0.2, respectively).Tuberculosis was more frequent during the multifocal form (p = 0.05) and brucellosis during the unifocal form (p = 0.03). Disco-vertebral biopsy was performed in 79 cases. It was more often contributory during multifocal spondylodiscitis (p = 0.03).The occurrence of immediate complications was more frequent in multifocal spondylodiscitis but with no statistically significant difference (p=0.2).Conclusion:Multifocal sppondylodiscitis is seen mainly in immunocompromised subjects. Our study found that diabetes is the most common factor in immunosuppression. Note also the predominance of involvement of the posterior elements, tuberculous origin and immediate complications.Disclosure of Interests:None declared

scholarly journals Fast Accurate and Automatic Brushstroke Extraction

2021 ◽  
Vol 17 (2) ◽  
pp. 1-24
Author(s):  
Yunfei Fu ◽  
Hongchuan Yu ◽  
Chih-Kuo Yeh ◽  
Tong-Yee Lee ◽  
Jian J. Zhang
Keyword(s):  
Neural Network ◽  
Efficient Algorithm ◽  
Deep Neural Network ◽  
High Efficiency ◽  
State Of The Art ◽  
High Reliability ◽  
The Other ◽  
Manual Annotation ◽  
Stroke Extraction ◽  
Art Research

Brushstrokes are viewed as the artist’s “handwriting” in a painting. In many applications such as style learning and transfer, mimicking painting, and painting authentication, it is highly desired to quantitatively and accurately identify brushstroke characteristics from old masters’ pieces using computer programs. However, due to the nature of hundreds or thousands of intermingling brushstrokes in the painting, it still remains challenging. This article proposes an efficient algorithm for brush Stroke extraction based on a Deep neural network, i.e., DStroke. Compared to the state-of-the-art research, the main merit of the proposed DStroke is to automatically and rapidly extract brushstrokes from a painting without manual annotation, while accurately approximating the real brushstrokes with high reliability. Herein, recovering the faithful soft transitions between brushstrokes is often ignored by the other methods. In fact, the details of brushstrokes in a master piece of painting (e.g., shapes, colors, texture, overlaps) are highly desired by artists since they hold promise to enhance and extend the artists’ powers, just like microscopes extend biologists’ powers. To demonstrate the high efficiency of the proposed DStroke, we perform it on a set of real scans of paintings and a set of synthetic paintings, respectively. Experiments show that the proposed DStroke is noticeably faster and more accurate at identifying and extracting brushstrokes, outperforming the other methods.

scholarly journals A Review of Bolt Tightening Force Measurement and Loosening Detection

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3165 ◽  
Author(s):  
Rusong Miao ◽  
Ruili Shen ◽  
Songhan Zhang ◽  
Songling Xue
Keyword(s):  
Force Measurement ◽  
Axial Stress ◽  
High Stress ◽  
Bolted Joints ◽  
Practical Applications ◽  
Tightening Force ◽  
Existing Structures ◽  
Strength Failure ◽  
Joint Connection ◽  
Art Research

Pre-stressed bolted joints are widely used in civil structures and industries. The tightening force of a bolt is crucial to the reliability of the joint connection. Loosening or over-tightening of a bolt may lead to connectors slipping or bolt strength failure, which are both harmful to the main structure. In most practical cases it is extremely difficult, even impossible, to install the bolts to ensure there is a precise tension force during the construction phase. Furthermore, it is inevitable that the bolts will loosen due to long-term usage under high stress. The identification of bolt tension is therefore of great significance for monitoring the health of existing structures. This paper reviews state-of-the-art research on bolt tightening force measurement and loosening detection, including fundamental theories, algorithms, experimental set-ups, and practical applications. In general, methods based on the acoustoelastic principle are capable of calculating the value of bolt axial stress if both the time of incident wave and reflected wave can be clearly recognized. The relevant commercial instrument has been developed and its algorithm will be briefly introduced. Methods based on contact dynamic phenomena such as wave energy attenuation, high-order harmonics, sidebands, and impedance, are able to correlate interface stiffness and the clamping force of bolted joints with respective dynamic indicators. Therefore, they are able to detect or quantify bolt tightness. The related technologies will be reviewed in detail. Potential challenges and research trends will also be discussed.

scholarly journals A Survey of Robots in Healthcare

Technologies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Maria Kyrarini ◽  
Fotios Lygerakis ◽  
Akilesh Rajavenkatanarayanan ◽  
Christos Sevastopoulos ◽  
Harish Ram Nambiappan ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
State Of The Art ◽  
The Elderly ◽  
Robotic Systems ◽  
Care Hospital ◽  
Robotic Technology ◽  
Persons With Disabilities ◽  
Survey Paper ◽  
Recent Advances ◽  
Art Research

In recent years, with the current advancements in Robotics and Artificial Intelligence (AI), robots have the potential to support the field of healthcare. Robotic systems are often introduced in the care of the elderly, children, and persons with disabilities, in hospitals, in rehabilitation and walking assistance, and other healthcare situations. In this survey paper, the recent advances in robotic technology applied in the healthcare domain are discussed. The paper provides detailed information about state-of-the-art research in care, hospital, assistive, rehabilitation, and walking assisting robots. The paper also discusses the open challenges healthcare robots face to be integrated into our society.

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