Angle Measurement Device Research Articles

Investigation of Electrospun Polyacrylonitrile and Cellulose Acetate Smart Nanofibers Doped with Expanded Graphite for the Structure and Photothermal Effect

In this study, photothermal effect by doping expanded graphite (EG) to smart nanofibers produced by electrospinning method was investigated. Fourier transform infrared (FT-IR) spectroscopy was exploited for chemical characterization. Thermal analysis experiments were carried out by heating and cooling curves. Surface morphology of the produced materials was investigated through scanning electron microscope (SEM). Contact angle was determined through contact angle measurement device. The appearance of the peak of the characteristic cyano group in the structure of Polyacrylonitrile (PAN) at 2237.02 cm-1 in the nanofibers having different percentages synthesized with EG and PAN was accepted as the evidence of PAN nanofibers formation. The temperature platforms in the heating/cooling curves exhibited that the temperature of the PAN and cellulose acetate (CA) nanofibers mixed with different EG percentage have higher than pristine nanofibers. The surfaces of the EG@PAN and EG@CA nanofibers were homogeneously distributed fibrous, excessive EG heterogeneously dispersed or electrosprayed in shape. The maximum contacts angles were measured as 67.96° and 52.88° for nanofibers synthesized with EG@CA and EG@PAN, respectively. As the result, the temperature of the nanofibers mixed EG at different percentages increased resulting from having the higher thermal conductivity of EG. Main goal of the study is both investigating photothermal effect in PAN and CA electrospun nanofibers doped with EG of activating heat accumulation property of the produced smart nanofibers for heat energy production from the solar. Thus, it will be possible to develop a new promising method in the production of the smart textile products that have the storage capacity of the solar energy.

An open microfluidic design for contact angle measurement

Spontaneous capillary flow in open microchannels is a phenomenon driven by surface energies. The contact angle that the liquid forms with the channel's substrate material and the cross-section of the microchannel decide whether liquid from a connected reservoir will automatically fill the channel or not. In this work we show how this behavior can be used to design a passive contact angle measurement device (CAMD) based on parabolic open microgrooves. To that end, we present a theory of open capillary flow in such microgrooves and compare the results to minimal energy surface simulations. Additionally, we discuss that the condition for capillary flow of curved microchannels is essentially equal to the condition for their straight counterparts having the same cross-section. Lastly, we present two demonstrators of our CAMD made out of micromilled poly(methyl methacrylate). The devices consist of five open microchannels with different cross-sections which are connected to a common liquid reservoir. We show how the behavior of a liquid placed into that reservoir can be used to evaluate the contact angle between the liquid and the substrate material. A comparison to conventional contact angle goniometry shows that our approach is able to successfully estimate contact angles with an accuracy of 10° by design which can be improved by employing a greater number of microchannels. Since our devices were automatically designed and can be tuned to specific applications, this provides an easy approach to include contact angle measurement into existing lab-on-a-chip devices.

Surface and Adhesion Properties of a Softener Containing Fragrances Microencapsulated with Poly (Methyl Methacrylate) on Cotton, Polyester, and a Mixture of Cotton and Polyester Fabrics

The distribution and adhesion of microcapsules on fabric surfaces are crucial factors for the production of long-lasting fragrance textiles. The objective of this research was to study the adhesion property of a softener containing microencapsulated fragrances on fabrics. Pink fruity fragrance (PF), and white floral fragrance (WF) were encapsulated with poly (methyl methacrylate) or PMMA, using the micro-suspension photopolymerization method, to form PF-PMMA, and WF-PMMA microcapsules, respectively. The particle sizes and zeta potential of the capsules were determined. The PF-PMMA and WF-PMMA were added to the fabric softener before being applied to three types of fabrics, cotton, TK (polyester), and TC (a mixture of cotton and TK). Surface morphologies of the fabrics treated with the softener were studied by scanning electron microscope (SEM). Interactions between the microcapsules and the fabrics were studied using a contract angle measurement device, Fourier Transform Infrared (FTIR) spectrometer, and Raman microscope. The average size of PF-PMMA was 484.8 ± 4.0 nm, smaller than that of WF-PMMA (664.6 ± 2.9 nm). Cotton was found to be hydrophilic with a rough surface due to cellulose fibers, while TK surface was smooth and hydrophobic. The different fiber structures and surface properties of the fabrics gave rise to different adhesion behavior, evidenced by the contract angle and Raman microscopic data. After 60 days of storage, the microencapsulated fragrances were found to remain on the cotton surfaces, but that on the TC and the TK surfaces disappeared. The results illustrated the interaction between the fabric surface and the microcapsules encapsulated with fragrances, which affected their adhesion. The knowledge obtained can be applied to the development of household products with long-lasting fragrances.

Liquid Concentration Measurement Based on Liquid Contact Angle

Different concentrations of the same liquid or liquids with different solutes have different surface tensions. The macroscopic phenomenon is that they have different wetting effects on the same solid surface. The liquid contact angle can describe the wetting effect. Therefore, this paper proposes a method for measuring the liquid concentration using the liquid contact angle. A glass plate with a hydrophobic layer and an angle-measuring device forms the detection part. The glass plate is placed horizontally, and the solution to be tested is dropped on the surface of the glass plate. Solutions with different concentrations have different liquid-solid interfacial tension and liquid-gas interfacial tension, resulting in different liquid contact angles, which can achieve rapid and accurate measurement of solution concentration. Experiments show that the liquid contact angle of ethanol solution decreases with the increase of liquid concentration. Different volumes of ethanol solutions with the same concentration have substantially the same liquid contact angle. This experimental method has the advantages of being simple and easy to operate, having a wide range of applications, not easily limited by the type of detection solution, having a large concentration measurement range, having less sample usage, free from electromagnetic interference, and having real-time online detection.

Triphenylamine-based COFs composite membrane fabricated through oligomer-triggered interfacial polymerization

Covalent organic frameworks (COFs) are attractive innovative crystalline porous materials that have immense potential for the production of high-performance nanofiltration membranes. Although the conventional water-organic interfacial polymerization process has been broadly applied to fabricate COFs composite membranes on polymeric substrates, it cannot be applicable for COFs constructed by poorly water-soluble aromatic amine monomers. Herein, we report the fabrication of triphenylamine-based COFs composite membranes via an oligomer-triggered interfacial polymerization (OT-IP) process on a hydrolyzed polyacrylonitrile (HPAN) substrate, in which the interfacial reaction occurred between an acetic acid aqueous solution and an organic solution of 1,3,5-triformylphloroglucinol (Tp) in n-hexane and tris(4-aminophenyl)amine (TAPA) in mesitylene premixed in a short time. The Tp-TAPA oligomers generated during the premixing were characterized in terms of morphology and molecular weight. The TpTAPA film formation during the OT-IP process was in situ observed through an optical contact angle measurement device. The TpTAPA/HPAN composite membranes displayed a water permeance of 68.1 L⋅m−2⋅h−1·bar−1, and the rejections of different dye (EBT, CR) and drug (DG, AG) molecules above 92.0%. In addition, the composite membrane showed excellent stability in acidic solution and continuous filtration for 75 h. The results indicated that the OT-IP approach is a feasible and efficient approach to fabricate triphenylamine-based COF composite membranes with water-insoluble monomers.

Axial and radial crushing behaviour of thin-walled carbon fiber-reinforced polymer tubes fabricated by the real-time winding angle measurement system

This paper proposed a real-time winding angle measurement device embedded in the portable 3-axis winding machine, which was used to detect and measure the winding angle during the winding process. The device was completely designed, fabricated, tested, and divided into hardware and software sections. The hardware section was adopted Raspberry Pi 3B+ and Arducam 5MP OV5647 camera modules, and the software section was used the OpenCV software. The experimental test was carried out to validate the measurement data on ±45°, ±60°, and ±75° winding angles, and filament-wound carbon fiber-reinforced polymer tubes were performed the quasi-static radial and axial compression tests. It was found that the real-time measurement data from the system had approximately 0.45±0.02 comparative error value than the targeted winding angle, which was more accurate than traditional measurement data. Moreover, it was shown that peak crushing loading significantly increased with increasing winding angle under radial compression, which had the inverse decreasing trend under axial loading. In addition, the crushing behaviour of thin-walled CFRP tubes was studied.

Development of the real-time winding angle measurement device for the laboratory-scale 3-axis winding machine

It is well-known that an automatic system can reduce errors to a great extent, which increases productivity and reduces labor costs. The existing filament winding machines or equipment lack the winding angle detection or measurement system, which cannot provide high precision and stable winding angle. This paper proposes a real-time winding angle device that can detect and measure the fiber orientation of filament wound composite products. The real-time winding angle measurement system consists of an Arducam 5MP OV5647 camera and OpenCV software. It is developed as the programming function for processing the real-time image of the winding angle. Furthermore, the traveled movement slider and the winding angle measurement image can be acquired during the dry/wet process. The laboratory-scale 3-axis winding machine integrated with the real-time winding angle measurement device is successfully developed, assembled, and tested.

Motion Trajectories Prediction of Lower Limb Exoskeleton Based on Long Short-Term Memory (LSTM) Networks

A typical man–machine coupling system could provide the wearer a coordinated and assisted movement by the lower limb exoskeleton. The process of cooperative movement relies on the accurate perception of the wearer’s human movement information and the accurate planning and control of the joint movement of the lower limb exoskeleton. In this paper, a neural network and a Long-Short Term Memory (LSTM) machine learning model method is proposed to predict the actual movement trajectory of the human body’s lower limbs. Then a wearable joint angle measurement device was designed for gait trajectory prediction, which can be used for predictive control through machine learning methods. The experimental results show that the LSTM model can accurately predict the gait trajectory with an average mean square error. This method has practical significance for prediction the trajectory of the lower limb exoskeleton.

Assessment of Spatio-Temporal Parameters of Human Gait Using Fiber Bragg Grating Sensor-Based Devices

Gait analysis is vital from the view of its established capacity as an indicator for neuromuscular disorders. Gait analysis is carried out in order to provide a quantified assessment of human movement which may aid orthopaedic and podiatric fraternity to suggest suitable therapeutic treatment. The proposed study comprises of two wearable non-invasive devices realized using FBG sensors i.e. Knee Angle Measurement Device (KAMD) for dynamic knee angle measurement and Forefoot Load Measurement Device (FLMD) for dynamic measurement of load on the forefoot. In the present study, the assessment of locomotion is illustrated and analyzed utilizing the developed devices without any time synchronization complexity. During locomotion, the swing and the stance phase is analyzed with respect to both knee joint angle and forefoot load which further reveals the complementary nature between them. In addition, FLMD can also be utilized for the evaluation of single and double limb support phases during locomotion. Furthermore, the novel cantilever approach utilized in the FLMD design ensures to acquire the load imparted specifically over the forefoot region which facilitates FLMD to be employed for assessment of other locomotory actions such as landing phase analysis during leaps, climbing stairs, treadmill tests etc. Also, the cantilever approach helps minimize the hysteresis effects on the device.

Characterization and mechanical properties of TiO2 nanotubes formed on titanium by anodic oxidation

The well-ordered titanium dioxide (TiO2) nanotube array surfaces were formed at different voltages such as 20 V, 40 V, 60 V, 80 V and 100 V for 1 h on cp-Ti by anodic oxidation (AO) technique. And then, to improve crystallinity of the surface, heat treatment was applied at 450 °C for 1 h to all surfaces without any morphological changing. The surface and cross sectional morphology, elemental structure, phase composition, functional groups, roughness and thickness, wettability and mechanical results were investigated by SEM, EDX, XRD, FT-IR, AFM, contact angle measurement device and nanoindentation tester, respectively. Mainly, anatase- and rutile-TiO2 phases were obtained at post-heat treatment whereas only, Ti phase was detected on AO surfaces at pre-heat treatment. All nanotube structures and the elements of Ti and O were uniformly distributed through the whole surface. The roughness and thickness of tube structures usually increased with increasing voltage values and measured. The roughness and thickness values were measured as 10.67–111.97 nm and 0.21–1.92 μm, respectively. TiO2 nanotube surfaces exhibited hydrophobic behaviors with respect to plain Ti surface. Furthermore, mechanical properties such as hardness and elastic modulus of the coating produced at minimum voltage were great compared to ones at higher voltage and plain Ti surface under a Berkovich indenter due to phase structure, homogeneity and density of nanotube structures.

Development of Static and Kinetic Friction Coefficient Experiment Device Based on Arduino Uno

The concept of friction makes physics more realistic. Based on research, physics education students are still experiencing misconceptions or do not understand the concept of the friction coefficient. Experimental tools commonly used in practicum have not been able to measure the coefficient of friction properly. The purpose of this research is to design a static and kinetic friction coefficient experiment that can be used in basic physics practicum. This study uses the ADDIE model which is carried out to the stage of develop or media development. The experiment was developed using the principle of sliding beams in an inclined plane by using an Arduino Uno microcontroller and sensors as a time and angle measurement device. The experiments designed to observe the effect of differences in mass and surface roughness on the friction coefficient. this device can measure the value of μs and μk simultaneously. The time measurement precision value of the tool is 93% and the angle measurement precision is 98.0%. The experiment succeeded in proving that μs > μk , surface roughness affects the value of the coefficient of friction and the mass does not affect the value of the coefficient of friction.

Dual-axis optical spatial heterodyning angle measurements using CMOS sensor color crosstalk

A simple, yet precise, optical angle measurement device was developed by analyzing the light interference pattern from a modified Lloyd’s mirror interferometer combined with a CMOS camera sensor. The resulting spatially heterodyned signal was very sensitive to small angle changes from an incident low-power laser beam, with an accuracy better than 8.9 arcsec over a range of 1.47 degrees. Measurement dead zones, estimated to have an angular span of ± 0.96 arcmin, occurred in the middle of the device’s measurement range at a critical angle where the pitches of the light interference pattern and the CMOS sensor array were equal. Also, a proof-of-concept test successfully demonstrated the use of this device for dual-axis angle measurements using a single CMOS sensor.

Feasibility and reliability of a web-based smartphone application for joint position measurement.

ObjectiveMeasurement of joint angles is usually performed using a simple goniometer, which can often be time-consuming and inaccurate, however smartphones can measure angles, this technology could be used to measure joint position. Studies of smartphone applications for this purpose lack consistency and homogeneity. The aim of the current study is to analyse the reliability and accuracy of 3 inertial motion unit-based smartphone applications for goniometric measurement, using 3 different industry standards as external controls.MethodsIn the first 2 phases of the study, measurements of angles between 90° and 165° (simulating knee extension) using 3 smartphone applications were analysed against the 3 industry standards. In the third phase, the smartphone’s raw data was individually analysed against a digital inclinometer across the x, y and z axes.Results and conclusionResults from the 3 phases of this study indicate a high degree of reliability and validity of the applications compared with the industry standards, with no clinically significant deviations. Thus, this technology could be used in a clinical setting. However, further clinical research, focussing on joint motions with greater than a single degree of freedom, is required before the use of such applications for joint position measurement in clinical practice.LAY ABSTRACTThe range of movement of various joints in the human body is regularly measured in a clinical setting, using a traditional angle measurement device (a goniometer), during functional assessments by doctors and physical and occupational therapists. However, such measurements can often be time-consuming and inaccurate. This study analysed the accuracy of smartphone apps for measuring joint angles compared with a goniometer. The results show that smartphone apps could be a good alternative for measuring joint angles.

Design of a precise subdivision system for gratings using a modified CORDIC algorithm

The authors have proposed a robust linearisation method for determining the angles of sinusoidal signals generated by gratings. This scheme solves the problem of non-linear subdivision by compensating sinusoidal signal. The conventional coordinate rotation digital computer (CORDIC) algorithm is optimised by double-rotation iteration, and the calculation accuracy of arcsine and arccosine functions is improved. A pipeline preprocessing circuit based on the CORDIC is designed for the signal compensation and digital subdivision. The two processes are implemented on a field-programmable gate array chip, which exhibits a wide input range and good dynamic response. A theoretical analysis using stable signals from a function generator verifies that the subdivision system achieves the ideal subdivision effect. The subdivision system is further applied to an angle-measuring device for a 16,384-line circular grating. The results of subdivision exhibit good linearity for the grating moire signal. Compared to the angular measurement by a laser interferometer within the three grating lines, the angle-measurement accuracy of ±0.000138° (0.5″) and the relative error is ±0.63% over a travel angle of three grating lines. Notably, the measurement error of the subdivision system is only half of that in a similar commercial product (MicroE system).

Superhydrophobic nickel coating fabricated by scanning electrodeposition

A scanning electrodeposition technology was proposed to fabricate superhydrophobic nickel coating. The microstructure, the surface chemical composition, and the wettability of the coating were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle-measuring device. The SEM images showed that there were cauliflower-like clusters on the coating surface, which were attributed to the “tip effect”. The newly prepared coating was not superhydrophobic, but after exposed to air for one week, the contact angle of a 6 μL water droplet on the surface reached 155.4° and the sliding angle was only 6.5°. The XPS analyses indicated that this phenomenon was due to the adsorption of organic compounds from the air. This method has potential for practical applications, as it is flexible and controllable, simple and fast, and the prepared coating showed an excellent superhydrophobic property.

Knee Angle Measurement Device Using Fiber Bragg Grating Sensor

Human joint kinematics has established its capacity as a vital tool for joint pathology and gait analysis. Range of motion (ROM) of a knee joint performed by flexion and extension is an essential tool to assess the efficacy of surgical interventions or therapeutic assessment. This paper proposes a novel wearable device for dynamic measurement of knee joint angle using fiber Bragg grating (FBG) sensor. The proposed knee angle measurement device (KAMD) can transduce the angular movement between the shin and the thigh into strain variations on a cantilever, which is acquired by the FBG sensor over it. The KAMD is also facilitated with tuneable sensitivity with three modes of high sensitivity mode, medium sensitivity mode, and low sensitivity mode, which can be opted based on application specific resolution and range of measurement. The ROM data obtained from the KAMD are validated against ROM obtained from commercially available Polhemus Sensors. Furthermore, the synchronization of the knee joint movement of both legs during walking along with stance and swing phase is illustrated, which shows the ability of KAMD to perform gait analysis. Employment of KAMDs on both legs eliminating the time synchronization complexity makes the proposed FBG-based KAMD an efficient means to evaluate the knee angle from both legs simultaneously.

Retrieving 2-D Leaf Angle Distributions for Deciduous Trees From Terrestrial Laser Scanner Data

Terrestrial laser scanning is a promising tool for estimating leaf angle (including leaf inclination and azimuthal angles) distribution (LAD). However, previous studies focus on the retrieval of leaf inclination angle distribution, very few studies have considered the distribution of leaf azimuthal angle due to the restriction of measurement techniques. In this paper, we developed a new method to obtain more accurate leaf inclination and azimuthal angle estimations based on leaf point cloud segmentation and filtration and then fit LAD functions using two-parameter Beta-distribution model. In addition, we constructed a new projection coefficient model with two parameters $G(\theta $ , $\varphi$ ) using Nilson’s algorithm based on the accurate retrieval of LAD. To assess the influence of leaf numbers on leaf inclination and azimuthal angle estimations, we modeled 160 individual leaves and 10 trees with different leaf numbers. In addition, to validate the final results, we also sampled three magnolia trees with different leaf numbers and manually measured leaf inclination and azimuthal angles of all their leaves using an angle measurement device. All results showed that the method proposed in this paper can provide accurate leaf inclination and azimuthal angles (leaf inclination angle: $R^{2} = 0.98$ , RMSE = 24° and leaf azimuthal angle: $R^{2} = 0.99$ , RMSE = 3.44°). The simulated LAD and $G(\theta $ , $\varphi$ ) estimations based on these leaf inclination and azimuthal angles were strongly correlated with those obtained from ground truth measurements ( $P >0.05$ ).

In vitro evaluation of the contact angle formed between AH Plus, Hybrid Root Seal and mineral trioxide aggregate Plus sealer with dentin and gutta-percha.

Aim:The purpose of this study was evaluation and comparison of the contact angle of new root canal sealers – Hybrid Root Seal, mineral trioxide aggregate (MTA) Plus, and the conventional AH Plus sealer with dentin and gutta-percha.Materials and Methods:Two groups (Group D – dentin and Group G – gutta-percha) of 18 samples each were further randomly divided into 3 subgroups based on the type of sealer used, that is, AH Plus, Hybrid Root Seal, and MTA Plus. Contact angle measurement device (Phoenix 300) was used to measure the contact angle of the sealers on both dentin and gutta-percha. The results thus obtained were analyzed using one-way analysis of variance and Student's t-test.Results:MTA Plus recorded significantly higher values of contact angle on both the substrates, that is, dentin and gutta-percha when compared to AH Plus and Hybrid root canal sealer. The lowest value of contact angle in gutta-percha and dentin was shown by Hybrid root canal sealer and AH Plus, respectively.Conclusion:Both AH Plus and Hybrid Root Seal exhibited lower contact angle values, and hence, better wettability on both dentin and gutta-percha as compared to MTA Plus.

The influence of the topography and physico-chemical properties of the cuticle surface on the wettability and adhesive properties of the elytra of the dung beetle Geotrupes stercorarius (Coleoptera, Scarabaeidae)

The elytral surface of dung beetles is generally accepted to be self-cleaning due to its anti-adhesive properties. In this article, the wettability and adhesive properties of elytral surface (intact and treated with Acetone and Ethanol) of the beetle Geotrupes stercorarius were characterized. Since these properties are influenced by the surface structure and chemistry, the micro- and nanostructure of the elytra were observed using scanning electron microscopy and the surface roughness were estimated with white light interferometery, whereas the water contact angle and adhesion force of the elytra were evaluated using contact angle measurement device and force transducer, respectively. The results show that the microstructure of the elytra changed greatly after different chemical treatments and the changes in wettability were mainly related to the changes of elytra roughness after treatments. The differences in adhesion force between differently treated elytra and wet sand indicate that the molecular polarity of the elytral surface is decisive for its anti-adhesive (self-cleaning) property.

Effect of TiO2 nanoparticles on wettability and tribological performance of aqueous suspension

Aqueous suspensions containing different concentration of nano-TiO2 (50nm) are prepared, in which sodium polyacrylate (PAAS) as the dispersant is used. Their wettability and tribological properties are discussed with Dataphysics OCA50 contact angle measurement device and the MRS-10A four-ball tester, respectively. The rubbed surfaces after friction tests are also analyzed by scanning electron microscope (SEM) equipped with Energy Dispersive Spectrometer (EDS). Wetting results show that the wettability of aqueous suspension is sharply deteriorated with the addition of PAAS, possibly caused by adsorption of PAAS on the substrate alters the characterization of the substrate, which promote the substrate change from homogeneity to heterogeneity, and eventually the wetting state transits from Wenzel to Cassie. And when the nano-TiO2 is further added to the aqueous suspension, the wettability is slightly better, which is mostly due to adsorbed sodium polyacrylate desorb from substrate surface and return to the body phase. In another aspect, four-ball experimental results reveal that the nano-TiO2 as the additive exhibits good anti-wear and friction reduction properties as well as load-carrying capacity. SEM analysis indicates that nano-TiO2 is deposit on the rubbed surface and so prevents direct contact of tribo-pairs.