Standardization of meibomian gland dysfunction in an Egyptian population sample using a non-contact meibography technique

AIM:To develop normative data for meibomian gland dysfunction(MGD)parameters,using non-contact meibography technique of Sirius Costruzione Strumenti Oftalmici(CSO)machine,in an Egyptian population sample.METHODS:Observational,cross-sectional,analytic study,in which 104 Egyptian volunteers were included.Both upper lids were examined,using“Sirius CSO”machine.Each eyelid was given a degree of meibomian gland loss(MGL),which was calculated by the software of the machine.RESULTS:Mean percentage MGL in right upper lid was of 30.9%±12.6%,and that of left upper lid was 32.6%±11.8%.Thirty-four volunteers(32.7%)had first-degree MGL in their right upper lid,and 67.3%had second-degree loss.One volunteer(1%)had zero-degree MGL in left upper lid,28(26.9%)had first-degree loss,and 75(72.1%)had second-degree loss.Degree of MGL in right upper eyelid was not related to age,but degree of MGL in left upper eyelid increased with age.There was statistically significant difference between both genders for degree of MGL in right eye(P=0.036)and in left eye(P=0.027).CONCLUSION:Noncontact meibography is a useful non-invasive tool for diagnosing MGL.MGL is diagnosed in 100%of apparently normal individuals;26.9%-32.7%of which have first-degree MGL,and 67.3%-72.1%have second-degree MGL.

Non-contact wide-field viewing system-assisted scleral buckling surgery for retinal detachment in silicone oilfilled eyes

AIM:To evaluate scleral buckling(SB)surgery using a noncontact wide-field viewing system and 23-gauge intraocular illumination for the treatment of rhegmatogenous retinal detachment in silicone oil(SO)-filled eyes.METHODS:Totally 9 patients(9 eyes)with retinal detachment in SO-filled eyes were retrospectively analyzed.All patients underwent non-contact wide-field viewing system-assisted buckling surgery with 23-gauge intraocular illumination.SO was removed at an appropriate time based on recovery.The patients were followed up for at least 3mo after SO removal.Retinal reattachment,complications,visual acuity and intraocular pressure(IOP)before and after surgery were observed.RESULTS:Patients were followed up for a mean of 8.22mo(3-22mo)after SO removal.All patients had retinal reattachment.At the final follow-up,visual acuity showed improvement for 8 patients,and no change for 1 patient.The IOP was high in 3 patients before surgery,but it stabilized after treatment;it was not affected in the other patients.None of the patients had infections,hemorrhage,anterior ischemia,or any other complication.CONCLUSION:This new non-contact wide-field viewing system-assisted SB surgery with 23-gauge intraocular illumination is effective and safe for retinal detachment in SO-filled eyes.

Benchmarking dynamic properties of structures using non-contact sensing

Non-contact sensing can be a rapid and convenient alternative for determining structure response compared to conventional instrumentation.Computer vision has been broadly implemented to enable accurate non-contact dynamic response measurements for structures.This study has analyzed the effect of non-contact sensors,including type,frame rate,and data collection platform,on the performance of a novel motion detection technique.Video recordings of a cantilever column were collected using a high-speed camera mounted on a tripod and an unmanned aerial system(UAS)equipped with visual and thermal sensors.The test specimen was subjected to an initial deformation and released.Specimen acceleration data were collected using an accelerometer installed on the cantilever end.The displacement from each non-contact sensor and the acceleration from the contact sensor were analyzed to measure the specimen′s natural frequency and damping ratio.The specimen′s first fundamental frequency and damping ratio results were validated by analyzing acceleration data from the top of the specimen and a finite element model.

Agreement of intraocular pressure measurement with Corvis ST,non-contact tonometer,and Goldmann applanation tonometer in children with ocular hypertension and related factors

AIM:To access the agreement of intraocular pressure(IOP)values obtained from biomechanically corrected tonometer[Corvis ST(CST)],non-contact tonometer(NCT),and Goldmann applanation tonometer(GAT)in children with NCT measured-IOP(NCT-IOP)values of 22 mm Hg or more,and related factors.METHODS:A total of 51 eyes with NCT-IOP≥22 mm Hg in children aged 7 to 14y were examined and IOP was measured by CST,NCT,and GAT.Based on GAT measured IOP(GAT-IOP),ocular hypertension(OHT)group(≥22 mm Hg,24 eyes)and the non-OHT group(<22 mm Hg,27 eyes)were defined.We compared the agreement of the three measurements,i.e.,CST measured IOP(CST-IOP),GAT-IOP,and NCT-IOP,and further analyzed the correlation between the differences in tonometry readings,central corneal thickness(CCT),axial length(AL),optic disc rim volume,and age.RESULTS:Compared with the OHT group,thicker CCT,larger rim volume,and higher differences between NCTIOP and GAT-IOP,were found in the non-OHT group.The differences between CST-IOP and GAT-IOP were lower than the differences between NCT-IOP and GAT-IOP in both groups.The mean differences in CST-IOP and GAT-IOP were 1.26 mm Hg(95%limit of agreement ranged from 0.1 to 2.41 mm Hg,OHT group)and 1.20 mm Hg(95%limit of agreement ranged from-0.5 to 3.00 mm Hg,non-OHT group),and the mean differences in NCT and GAT were 3.90 mm Hg(95%limit of agreement ranged from-0.19 to 9.70 mm Hg,OHT group)and 6.00 mm Hg(95%limit of agreement ranged from 1.50 to 10.50 mm Hg,non-OHT group).The differences between CST-IOP and GAT-IOP were not related to CCT,age,and AL in both groups;while the differences between NCT-IOP and GAT-IOP were related to CCT in the OHT group(r=0.93,P<0.001)and to CCT and AL in the non-OHT group(r=0.66,P<0.001,r=-0.81,P<0.001).CONCLUSION:The accuracy of NCT in the diagnosis of pediatric OHT is low.The agreement of CST-IOP and GATIOP was significantly higher in children with and without OHT than in those with NCT-IOP and GAT-IOP.Therefore,CST can be used as a good alternative for IOP measurement in children.The impacts of CCT and AL on NCT measurement need to be fully considered when managing childhood IOP.

Non-Contact System for Global Reporting Format (GRF) Automation: Contaminant Body Detection and Depth Estimation in the Case of Rainy Weather

The paper designed a non-contact system in order to perform the application (on a runway) of the Global Reporting Format (GRF) developed by International Civil Aviation Organization (ICAO). The system involves devices that film the surface (a runway in our case) from the air and displays the contaminant (water) body and measures the depth of the water automatically during the inspection. While measuring, data are sent to a computer used as a receiver. The developed devices are automatic devices implemented specially to use during rainy weather or even for some other cases. The aerial system uses a raspberry pi 4 model B, a camera, a laser sensor, an ultrasonic module, a Virtual Network Computing (VNC) and python codes developed by the authors. Results obtained show that using these devices to retrieve the Runway Condition Report (RCR) is very fast and human presence on the runway is not needed. The results obtained using these devices show that the method used herein is a proper solution to the GRF issues in the rainy areas, where the contaminant body detection and the accurate depth measurement were not well estimated because of the lack of a suitable method.

A non-contact spacecraft architecture with extended stochastic state observer based control for gravity mission

A novel non-contact spacecraft architecture with the extended stochastic state observer for disturbance rejection control of the gravity satellite is proposed.First,the precise linear driving non-contact voice-coil actuators are used to separate the whole spacecraft into the non-contact payload module and the service module,and to build an ideal loop with precise dynamics for disturbance rejection control of the payload module.Second,an extended stochastic state observer is enveloped to construct the overall nonlinear external terms and the internal coupled terms of the payload module,enabling the controller design of the payload module turned into the linear form with simple bandwidth-parameterization tuning in the frequency domain.As a result,the disturbance rejection control of the payload module can be explicitly achieved in a timely manner without complicated tuning in actual implementation.Finally,an extensive numerical simulation is conducted to validate the feasibility and effectiveness of the proposed approach.

A LASER-SCANNING NON-CONTACT MEASURING METHOD FOR ROUNDNESS ERRORS

利用激光狭缝扫描原理和光电传感技术，提出了一种用于测量大型回转体类零件圆度误差的激光扫描非接触测量方法和测量系统。本文详细论述了测量系统及其测量原理、工件安装偏心误差的分离技术和计算机实时数据处理系统，实验结果证实了这种测量方法的可行性。

Design of Non-contact On-load Automatic Regulating Voltage Transformer

At present, an automatic-mechanic contact tap-changer is widely used in power system, but it can not frequently operate. In addition, arc will occur when the switch changes. In order to solve these two problems, this paper presented an automatic on-load voltage-regulating distributing transformer which employed non-contact solid-state relay as tap-changer, and mainly introduced its structure, basic principal, design method of each key link and experimental results. Laboratory simulation experiments informed that the scheme was feasible. It was a smooth and effective experiment device, which was practical in application.

NON-CONTACT MEASUREMENT SYSTEM OF FREEFORM SURFACE AND NURBS RECONSTRUCTION OF MEASUREMENT POINTS

Based on the development of the non-contact measurement system of free-formsurface, NURBS reconstruction of measurement points of freeform surface is effectively realized bymodifying the objective function and recursive procedure and calculating the optimum number ofcontrol points. The reconstruction precision is evaluated through Ja-cobi's transformation method.The feasibility of the measurement system and effectiveness of the reconstruction algorithm aboveare proved by experiment.

Non-contact tensile viscoelastic characterization of microscale biological materials

Many structures and materials in nature and physiology have important ＂meso-scale＂ structures at the micron lengthscale whose tensile responses have proven difficult to characterize mechanically. Although techniques such as atomic force microscopy and micro- and nano-identation are mature for compression and indentation testing at the nano-scale, and standard uniaxial and shear rheometry techniques exist for the macroscale, few techniques are applicable for tensile-testing at the micrometre-scale, leaving a gap in our understanding of hierarchical biomaterials. Here, we present a novel magnetic mechanical testing （MMT） system that enables viscoelastic tensile testing at this critical length scale. The MMT system applies non-contact loading, avoiding gripping and surface interaction effects. We demonstrate application of the MMT system to the first analyses of the pure tensile responses of several native and engineered tissue systems at the mesoscale, showing the broad potential of the system for exploring micro- and meso-scale analysis of structured and hierarchical biological systems.

Non-contact evaluation of the resonant frequency of a microstructure using ultrasonic wave

This paper presents a novel non-contact method for evaluating the resonant frequency of a microstructure, Firstly, the microstructure under test is excited by ultrasonic waves. This excitation method does not impose any undefined load on the specimen like the electrostatic excitation and also this is the first actual use of ultrasonic wave for exciting a microstructure in the literature. Secondly, the amplitudes of the microstructure are determined by image edge detection using a Mexican hat wavelet transform on the vibrating images of the microstructure. The vibrating images are captured by a CCD camera when the microstructure is vibrated by ultrasonic waves at a series of discrete high frequencies （〉30 kHz）. Upon processing the vibrating images, the amplitudes at various excitation frequencies are obtained and an amplitude-frequency spectrum is obtained from which the resonant frequency is subsequently evaluated. A micro silicon structure consisting of a perforated plate （192 × 192 μm） and two cantilever beams （76 × 43 μm） which is about 4 μm thickness is tested. Since laser interferometry is not required, thermal effects on a test object can be avoided. Hence, the setup is relatively simple. Results show that the proposed method is a simple and effective approach for evaluating the dynamic characteristics of microstructures.

Non-contact monitoring and analysis system for tunnel surrounding rock deformation of underground engineering

It is very important to monitor surrounding rock deformation in tunnel construction. The principle, function, development and application of the system composed of a total station and computer for monitoring and analyzing surrounding rock deformation were discussed. The new methods of two free station of 3D measurement and its mathematic adjustment mode were presented. The development of software for total station on-board and post for computer were also described. Without centering it and measuring its height, the total station controlled by the software on-board can fulfill the whole measurements to target points. Monitoring data can be processed by the post software and results of regression analysis, forecasting information of the tunnel surrounding rock deformation can be provided in time. The practical use shows that this system is practicable, highly accurate and efficient. It satisfies the needs of safety and information construction in tunnel construction of underground engineering.

An approach to a non-contact vital sign monitoring using dual-frequency microwave radars for elderly care

This study aimed to produce a prototype system for non-contact vital sign monitoring of the elderly using microwave radar with the intention of reducing the burdens on monitored individuals and nursing caregivers. In addition, we tested the ability of the proposed prototype system to measure the respiratory and heart rates of the elderly in a nursing home and discussed the systems effectiveness and problems by examining results of real-time monitoring. The prototype system consisted of two 24-GHz microwave radar antennas and an analysis system. The antennas were positioned below a mattress to monitor motion on the body surface for measuring cardiac and respiratory rates from the dorsal side of the subjects (23.3 ± 1.2 years) who would be lying on the mattress. The heart rates determined by the prototype system correlated significantly with those measured by electrocardiography (r = 0.92). Similarly, the respiratory rates determined by the prototype correlated with those obtained from respiration curves (r = 0.94). Next, we investigated the effectiveness of the prototype system with 7 elderly patients (93.3 ± 10.56 years) at a nursing home. The proposed system appears to be a promising tool for monitoring the vital signs of the elderly in a way that alleviates the need to attach electrodes overnight to confirm patient safety.

Machine learning empowered COVID-19 patient monitoring using non-contact sensing:An extensive review

The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),which caused the coronavirus disease 2019(COVID-19)pandemic,has affected more than 400 million people worldwide.With the recent rise of new Delta and Omicron variants,the efficacy of the vaccines has become an important question.The goal of various studies has been to limit the spread of the virus by utilizing wireless sensing technologies to prevent human-to-human interactions,particularly for healthcare workers.In this paper,we discuss the current literature on invasive/contact and non-invasive/noncontact technologies(including Wi-Fi,radar,and software-defined radio)that have been effectively used to detect,diagnose,and monitor human activities and COVID-19 related symptoms,such as irregular respiration.In addition,we focused on cutting-edge machine learning algorithms(such as generative adversarial networks,random forest,multilayer perceptron,support vector machine,extremely randomized trees,and k-nearest neighbors)and their essential role in intelligent healthcare systems.Furthermore,this study highlights the limitations related to non-invasive techniques and prospective research directions.

Numerical simulation of non-contact explosion by door breaching explosive

Aiming at the estimation of personal injury attached by counter-terrorist door breaching explosive blast wave, according to the actual scene, four typical application space models of count- er-terrorist door breaching explosives are established, and numerical simulation of air-blast wave propagation by non-contact explosion counter-terrorist door breaching explosive are achieved. The research results show that the overpressure behind the target door is attenuated deeply through the burglary resistant safety door, and the propagation of blast wave and the damage effect under differ- ent space conditions are obviously different.

Suppression of Vortex Precession in a Non-Contact Handling Device by a Circular Column

Vortex levitation attains non-contact handling by injecting air through a tangential nozzle into a cylindrical cup generating the swirling flow. The precessing of the swirling flow causes pressure fluctuation. This phenomenon becomes apparent as the gap between the cup and workpiece increases, which significantly disturbs the stability of conveyance. In this paper, suppression of pressure fluctuation by a cylindrical column that stabilizes the vortex levitation is described and its mechanism is mentioned. According to the experimental set up, the pressure was measured at the center of the workpiece and the wall of the cup;velocity field under the work piece was visualized by PIV. The result suggested that the larger diameter column denoted the effect on suppression of the fluctuation because the precessing of the swirling flow became stable. On the other hand, variation of the column thickness had insignificant effect on suppressing the fluctuation, but sucking force became weakened since the swirling velocity decreased.

Test on an Optimized Cylindrical Non-contact Piezoelectric Actuator

An optimization design for the cylindrical non-contact piezoelectric actuator is presented after analyzing the acoustic radiation pressure and acoustic viscous force.By adding the specific microstructure on the rotor to alter the near-field sound effect and maximize the use of high intensity acoustic field induced by the stator to drive the rotor,the rotor speed is increased.The finite element analysis of the acoustic field induced by a variety of rotors with different structures is conducted,A prototype is manufactured,the speed-test system for the actuator is built,and the driving characteristics are measured.The results suggest that the rotation speed of the rotor can reach 4 167r/min,which demonstrates that the driving characteristics of cylindrical non-contact piezoelectric actuator are successfully improved using the optimization method proposed.

Non-Contact Electromagnetic Exciter Design with Linear Control Method

A non-contact type force actuator is necessary for studying the dynamic performance of a high-speed spindle system owing to its high-speed operating conditions. A non-contact electromagnetic exciter is designed for identifying the dynamic coefficients of journal bearings in high-speed grinding spindles. A linear force control method is developed based on PID controller. The influence of amplitude and frequency of current, misalignment and rotational speed on magnetic field and excitation force is investigated based on two-dimensional finite element analysis. The electromagnetic excitation force is measured with the auxiliary coils and calibrated by load cells. The design is validated by the experimental results. Theoretical and experimental investigations show that the proposed design can accurately generate linear excitation force with sufficiently large amplitude and higher signal to noise ratio. Moreover, the fluctuations in force amplitude are reduced to a greater extent with the designed linear control method even when the air gap changes due to the rotor vibration at high-speed conditions. Besides, it is possible to apply various types of excitations： constant, synchronous, and non-synchronous excitation forces based on the proposed linear control method. This exciter can be used as linear-force exciting and controlling system for dynamic performance study of different high-speed rotor-bearing systems.

All-optical Quantitative Framework for Bioluminescence Tomography with Non-contact Measurement

In this contribution, we present an all-optical quantitative framework for bioluminescence tomography with non-contact measurement. The framework is comprised of four indispensable steps： extraction of the geometrical structures of the subject, light flux reconstruction on arbitrary surface, calibration and quantification of the surface light flux and internal bioluminescence reconstruction. In particular, the geometrical structures are retrieved using a completely optical method and captured under identical viewing conditions with the bioluminescent images. As a result, the proposed framework avoids the utilization of computed tomography or magnetic resonance imaging to provide the geometrical structures. On the basis of experimental measurements, we evaluate the performance of the proposed all-optical quantitative framework using a mouse shaped phantom. Preliminary result reveals the potential and feasibility of the proposed framework for bioluminescence tomography.

A Contact and Non-Contact Hybrid Profilometer with Large Range

A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring techniques. The ambiguity presented in conventional monochromatic interferometers is not present in the contact and non-contact measurement, and they have a virtually unlimited unambiguous range. For the contact measurement, the vertical measuring range is ±5 mm with a resolution of 1 nm and the horizontal measuring range is ±25 mm in x-range and y-range with a resolution of 1.25 μm; for the non-contact measurement, the vertical measuring range is ~5 mm with a resolution of 1 nm and the horizontal resolution better than 0.5 urn.