Test Jig Research Articles

Microstructure and texture evolution in AZX311 Mg alloy during in-plane shear deformation

The current study examined the deformation mechanisms, microstructure, and texture evolution in AZX311 Mg alloy sheets subjected to in-plane shear (IPS) deformation. Different levels of shear strains, with values 0.05, 0.10, and 0.15, were applied along the rolling direction (RD) using a specialized in-plane shear testing jig. The strain measurement for the applied shear deformation was conducted utilizing the digital image correlation (DIC) technique. The strain distribution was found to be nearly homogeneous over sufficiently large areas, thereby allowing the microstructural measurements to yield relevant statistical data. A thorough microstructural examination across the thickness using electron back-scattered diffraction (EBSD) revealed that the application of IPS strain led to the formation of a significant number of tensile twins (TTWs) in the sheet. This was evidenced by the emergence of two satellite peaks at the periphery of the pole figures. As the shear strain increased, the proportion of TTWs in the material also increased, encompassing the entire parent grain and leading to the formation of what has been termed as “all-twinned microstructure”. The microstructural and texture investigation after IPS deformation revealed that TTWs were the dominant deformation mechanism that defined the microstructure and texture under IPS deformation, while dislocation slip activity was dominated by prismatic slip, as evidenced by the resolved shear stress analysis in this study. Consequently, this research highlights the effect of IPS deformation on the microstructure and texture evolution throughout the thickness of an Mg alloy sheet and elucidates the underlying mechanisms.

Biomechanical impact of meniscal ramp lesions on knee joint contact characteristics in ACL deficient knees: a cadaveric analysis.

To evaluate the changes in contact characteristics of the tibiofemoral joint resulting from a meniscal ramp lesion in the medial meniscus. Twelve cadaveric knees (six matched pairs) were subjected to a 600N axial load using a custom testing jig, which allowed for knee positioning at 0°, 45°, and 90° of flexion without other constraints. The knees were randomly assigned to either a ramp lesion group (n = 6) or a posterior root lesion group (n = 6). Four testing conditions were examined: (1) intact, (2) isolated ramp lesion, (3) isolated posterior root tear of the medial meniscus, and (4) combined ramp lesion and posterior root tear of the medial meniscus. Contact characteristics were evaluated using a flexible pressure sensor, the I-Scan System. Peak contact pressure in isolated ramp lesions (4.15 ± 0.98MPa, P = 0.206) showed non-significant increases compared to the intact condition (3.86 ± 1.32MPa). Peak contact pressure in isolated posterior root tears (4.58 ± 1.70MPa, P = 0.040) and, combined ramp and posterior root lesions (4.67 ± 1.47MPa, P = 0.003) were significantly higher than that in the intact condition. The knee flexion position significantly affected the medial tibiofemoral joint's contact area, contact pressure, and peak contact pressure (P < 0.001 for all). Isolated ramp lesions did not significantly impact force transmission, contact area, or contact pressure. In contrast, isolated root lesions and combined ramp and posterior root tears of the medial meniscus significantly intensified the changes in contact characteristics in the medial tibiofemoral joint compared to the intact condition. Level III.

Assessment of Nanosilver Fluoride Application on the Microtensile Bond Strength of Glass Ionomer Cement and Resin-modified Glass Ionomer Cement on Primary Carious Dentin: An In Vitro Study.

Nanosilver sodium fluoride (NSF) has recently gained popularity in dentistry as an alternative to silver diamine fluoride (SDF) due to its drawbacks of staining the tooth black and possibly causing soft tissue injury, which has been eliminated in NSF due to the nanoparticle size of silver. This study aims to assess the microtensile bond strength of glass ionomer cement (GIC) and resin-modified glass ionomer cement (RMGIC) with pretreatment of NSF on extracted primary carious teeth. Teeth were stored in 10% formalin. The roots were severed, and the pulp chambers were cleaned. The occlusal enamel was ground, reducing the dentin thickness by 1 mm. The specimens were covered with nail varnish, leaving only the area of flat dentin exposed. Caries were induced microbiologically by inoculating Streptococcus mutans. Group I-NSF with GIC restoration, group II-NSF with RMGIC restoration, group III-restoration with GIC, and group IV-restoration with RMGIC. After different surface treatments of the carious dentin were performed, each specimen was placed in the testing jig of a universal testing machine and stressed in tension at a crosshead speed of 1 mm/minute until bond failure was observed. They were air-dried and placed under a scanning electron microscope. The failure modes-adhesive, cohesive, and mixed failure were recorded for statistical evaluation. Maximum results of microtensile bond strength were seen in the pretreatment group with NSF sealant, followed by RMGIC restoration, and the least results were observed in the conventional GIC restoration group. Of all the types of failures in our study, adhesive was the maximum type. The microtensile bond strength of pretreatment with NSF showed higher values when compared to conventional restorations of GIC and RMGIC. The failure modes in each group were not significantly varied. Pretreatment with NSF will prevent secondary caries formation, and the restorations will also be stronger. Das A, Ramamurthy N, Srinivasan I, et al. Assessment of Nanosilver Fluoride Application on the Microtensile Bond Strength of Glass Ionomer Cement and Resin-modified Glass Ionomer Cement on Primary Carious Dentin: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(5):565-569.

THE MANCHESTER PATTERN KNEE-SPANNING EXTERNAL FIXATOR: A MECHANICAL COMPARISON WITH TRADITIONAL EXTERNAL FIXATOR CONSTRUCTS

IntroductionKnee dislocations, vascular injuries and floating knee injuries can be initially managed by a external fixator. Fixator design constructs include the AO pattern and the Diamond pattern. However, these traditional constructs do not adhere to basic principles of external fixation. The Manchester pattern knee-spanning external fixator is a new construct pattern, which uses beam loading and multiplanar fixation. There is no data on any construct pattern. This study compares the stability of these designs.Materials &amp; MethodsHoffman III (Stryker, USA) external fixation constructs were applied to articulated models of the lower limb, spanning the knee with a diamond pattern and a Manchester pattern. The stiffness was loaded both statically and cyclically with a Bose 3510 Electroforce mechanical testing jig (TA Instruments). A ramp to load test was performed initially and cyclical loading for measurement of stiffness over the test period. The results were analysed with a paired t-test and ANOVA.ResultsThe mean stiffness with the diamond pattern fixator was significantly less stiff than the Manchester pattern fixator – by a factor of 3 (40N/mm vs 115N/mm). Displacement increased in all patterns over simulated loading equating to six weeks. The diamond pattern demonstrated a 50%% increase in displacement over time. The Manchester pattern demonstrated only 20% increase in displacement over time. These are all statistically significant (p&lt;0.01)ConclusionsThe aim of an external fixator in knee dislocations and vascular injuries is to provide stability, prevent displacement and protect repairs. Vascular injuries often require fixation for several weeks to protect a repair. The Manchester pattern, applying the principles of external fixation, provides a stiffer construct and also confers greater stability over the time a fixator may be required. We commend this more informed design for the management of knee dislocations and vascular injuries.

Fabrication and load test of ITER assembly tools for lifting heavy components

Korea Domestic Agency (ITER Korea, KODA) has procured 44 kind's assembly tools for ITER project. The assembly tools are classified by the steel structure, lifting table and lifting accessory. ‘PF 1, 6 and Central Solenoid Lifting Frame’ (CS Lifting Frame) and ‘Sector Lifting Tool’ (SLT) are the representative assembly tool classified the lifting accessory. The assembly tools handle the heavy component which over 1,000 tones for payload. In this reason, the verification of the strength of the tools is very important and the integrity of lifting accessory tools was verified by not only structural analysis but also load test at factory under 1.5 times the payload for minimum 15 min. It is the requirements of the technical specification. The main role of PF 1, 6 and CS Lifting Frame is to lift and transfer the ITER components (PF1 coil, PF6 coil and CS coil) from the assembly hall to the tokamak fit and their temporary support positions. The CS coil is heaviest component in payloads handled by CS Lifting Frame. The weight is about 1,000 tones and CS Lifting Frame was verified by 1,500 tones load test. Sector Lifting Frame is to lift and transfer the 40° sector module from Sector Sub-Assembly Tool (SSAT) to tokamak fit. The sector module consists of Vacuum Vessel (VV), VV Thermal Shield and Two Toroidal Flied Coils. The total weight of the sector module is about 1,300 tones and Sector Lifting Frame was verified by 2,000 tones load test. The load test was carried out according to test procedure approved by IO. This paper describes the overall test method, customized test JIG and result of the lifting tools for handling heavy components of ITER.

Open-Source Flexible Material Tensile Testing Apparatus

Alternative food sources are essential in both low-resource settings and during emergencies like abrupt sunlight reduction scenarios. Seaweed presents a promising option but requires investigation into the viability of unconventionally sourced ropes for harvesting. In this regard, a low-cost reliable method to test the tensile strength of rope is needed to validate alternative materials for use in harvesting seaweed. Commercial rope testing jigs alone range in price from several thousand to tens of thousands of dollars, so there is interest in developing a lower-cost alternative. Addressing these needs, this article reports on an open-source design for tensile strength rope testing hardware. The hardware design focuses on using readily available parts that can be both sourced from a hardware store and manufactured with simple tools to provide the greatest geographic accessibility. The jig design, which can be fabricated for CAD 20, is two to three orders of magnitude less expensive than commercially available solutions. The jig was built and tested using a case study example investigating denim materials (of 1 5/8”, 3 1/4”, 4 7/8”, 6 1/2”, and 8 1/8” widths) as a potential alternative rope material for seaweed farming. Denim demonstrated strengths of up to 1.65 kN for the widest sample, and the jig demonstrated sufficient strength and stiffness for operations at forces below 4 kN. The results are discussed and areas for future improvements are outlined to adapt the device to other circumstances and increase the strength of materials that can be tested.

Load-bearing capacity and wear characteristics of short fiber-reinforced composite and glass ceramic fixed partial dentures.

The aim of this study was to evaluate load-bearing capacity and wear performance of experimental short fiber-reinforced composite (SFRC) and conventional lithium-disilicate CAD/CAM fabricated fixed partial dentures (FPDs). Two groups (n = 12/group) of three-unit CAD/CAM fabricated posterior FPDs were made. The first group used experimental SFRC blocks, and the second group fabricated from lithium-disilicate (IPS e.max CAD). All FPDs were luted on a zirconia testing jig with dual-curing resin cement. Half of FPDs per group were quasi-statically loaded until fracture. The other half experienced cyclic fatigue aging (100.000 cycles, Fmax = 500 N) before loading quasi-statically until fracture. Fracture mode was examined using SEM. Wear test was performed using 15,000 loading cycles. Both material type and aging had a significant effect on the load-bearing capacity of FPDs. Experimental SFRC CAD without fatigue aging had significantly the highest load-bearing capacity (2096 ± 149N). Cyclic fatigue aging decreased the load-bearing capacity of the SFRC group (1709 ± 188N) but increased it for the lithium-disilicate group (1546 ± 155N). Wear depth values of SFRC CAD (29.3μm) were significantly lower compared to lithium-disilicate (54.2μm). Experimental SFRC CAD demonstrated the highest load-bearing capacity before and after cyclic fatigue aging, and superior wear behavior compared to the control material.

Active vibration control for reduction of interior noise caused by R-MDPS of electric power steering in electric vehicle

This paper presents a novel active vibration control (AVC) system for a motor driven power steering (MDPS) system to reduce interior noise in an electric vehicle. The novel control algorithm used for the AVC system is developed based on selection of two reference signals. One is the frequency modulation signal using the rotation speed of motor shaft of MDPS the other one is the band passed signal of acceleration measured on the major path structure identified by the blocked transfer path (BF-TPA). In addition, the piezo stack actuator is used for generation of control force of the AVC system in the frequency over 400 Hz. An MDPS system uses electronic power steering. An MDPS system attached to the rack gear of power steering system is called an R-MDPS. The vibration generated by the R-MDPS is transmitted to the car body through mounts attached onto the car subframe. Panel vibrations of car body are sources of vibroacoustic noise generated inside the car cabin. This vibracoustic noise is a structure-borne noise and causes passenger annoyance. The frequencies of the structure-borne noise measured inside the car cabin are 460 Hz and 920 Hz, which are the rotating frequency of the R-MDPS motor shaft and the second-order harmonic of the rotating speed of the motor shaft. To directly reduce the interior noise inside the car cabin, active noise control (ANC) has been used for the active cancellation of noises with frequencies less than 400 Hz. However, because the frequency of interior noise generated by the operation of the R-MDPS is higher than 400 Hz, AVC was employed in this study for the active cancellation of vibrations transmitted to the car body through the subframe mounts of the car. For application of AVC to the test car, the control force should be known. Therefore, the actuator for generating the control force should be inserted in the mount between the subframe and R-MDPS system. Installing the actuator in the test car is challenging because of the geometry limit of commercial cars. Hence, a test jig composed of an R-MDPS system and the subframe of the test car was developed and set up in the laboratory to study the applicability of AVC to R-MDPS. All investigations of AVC were performed using the test jig in the laboratory. The proposed method was successfully applied to the active cancellation of vibration at a target point on the subframe.

Magnetic Characteristics of a Magnetorheological Elastomer Bushing

The present study aims to investigate the magnetic characteristics of a magnetorheological elastomer (MRE) bushing for design optimization in the high-frequency dynamic test. The proposed design consists of MRE bushing covered cylindrically with the coil bobbin for electromagnetic coil winding. These components are covered with the testing jig attached to the testing machine. MRE experimental studies often show uncertainty in evaluating the magnetic distribution across the entire testing structure specifically in MRE specimens. A finite element model for MRE bushing is designed to evaluate the magnetic distribution of the device under several factors that can affect the magnetic distribution. The results of the model are optimized to obtain high magnetic flux density in the MRE area. The magnetic intensity (H) as a function of magnetic flux density (B) was also determined through the B-H relation curve. It was proved that the magnetic distribution is affected significantly by factors such as material components and current applied (Ampere) to the MRE bushing. The optimum MRE bushing design with 1 Ampere can reach the highest magnetic flux density of 960 mT. Therefore, an optimum magnetic distribution condition for MRE bushing can be realized in the real experimental study.

Active Vibration Control of Motor Driven Power Steering for Reduction of Interior Noise

This study presents a novel active vibration control (AVC) system on motor driven power steering (MDPS) to reduce interior noise reduction caused by operating the MDPS in an electric vehicle. MDPS is electronic power steering (EPS). The MDPS attached to the rack gear of power steering system is called R-MDPS. Operating of the R-MDPS generates a structural vibration of R-MDPS, and the vibration is transmitted to car body through mounts of car subframe. The vibrating body of car becomes a monopole and dipole sources of vibroacoustic noise generated inside car. This vibracoustic noise is a structure borne noise and makes passenger annoyance. To reduce interior noise inside a car directly, active noise control (ANC) has been used as active method and is a useful method for active cancellation of the low frequency noises less than 400Hz. However, in this study, because the frequency range of interior noise due to operation of R-MDPS is higher than 400Hz, the AVC system is employed and is applied to active cancellation of the vibration transmitted to car body through the subframe mounts. For application of AVC to test car, the control force is required and the actuator for generation of control force should be install on the mounts. For application of AVC to test car, the control force is required and the actuator for generation of control force should be inserted in the mount between subframe and R-MDPS. It requires an extra rework of test car. In this study to study the feasibility for the application of AVC system to R-MDPS, the test jig, which composes of R-MDPS and subframe of test car, is made and is set up in the laboratory. All study on AVC is performed in the laboratory. The proposed method is successfully applied to the active cancellation of vibration at target point of subframe. The developed method is going to be applied to the AVC of real test vehicle.

The effect of shoulder prosthesis stem length on failure due to torsional loading. A biomechanical study in composite humeri

Shoulder arthroplasty is becoming increasingly common. With evolving implant designs, multiple humeral stem options exist for the surgeon to choose from. New stemless and short-stem systems are modular, remove less native bone stock, and better adapt to patient anatomy. It has been suggested that shorter stem implants may be protective against periprosthetic fracture; however, this has not been mechanistically evaluated. Therefore, this study aimed to biomechanically test synthetic humeri with long-stem, short-stem, and stemless arthroplasty components in a torsional manner to evaluate their response to loading and characterize failure. Twenty-four synthetic humeri were implanted with long stem, short stem, or stemless uncemented prosthesis, 8 in each group. Humeri were mounted in a custom testing jig with a morse taper interfacing with a mechanical testing system. After a 20N axial force, specimens were torsionally loaded to failure at 15 degrees/sec, with 50 Hz collection. Torque vs. rotation curves were generated for each specimen, and stiffness, yield, ultimate strength, and failure load were measured. ANOVA and post hoc pairwise comparisons were used to assess effect of stem type on mechanical test variable. The association of the stem type with fracture type was analyzed by a Fisher's Exact test. Statistical significance was set at P<.05. During torsional loading, long-stem implants were significantly stiffer than short or stemless implants. The angle of implant yielding was similar across stem designs; however, stemless implants had a lower yield torque. This correlated with a decreased yield energy in stemless compared to short stems as well. Maximum torque and failure torque was also significantly higher in short-stem and long-stem implants compared to stemless. Periprosthetic fractures in shoulder arthroplasty are a concern in low-energy trauma, and stem design likely plays a significant role in early implant-bone failure. Our results suggest stemless implants under torsional load fail at lower stress and are less stiff than stemmed implants. The failure mechanism of stemless implants through metaphyseal cancellous bone emphasizes the effect bone quality has on implant fixation. There is likely a balance of torsional stability to survive physiologic loads while minimizing diaphyseal stress and risk of diaphyseal periprosthetic fracture. This combined with revision and fixation options represent decisions the surgeon is faced with when performing shoulder arthroplasty.

Developing Test Methods for Compression after Lightning Strikes

Research into residual strength after lightning strike is increasing within the literature. However, standard test methods for measuring residual compressive strength after lightning strikes do not exist. For the first time, a systematic experimental study is undertaken to evaluate modifications necessary to standard Compression After Impact (CAI) specimen geometry and test jig design to induce specimen failure at the lightning damage region. Four laboratory generated lightning strike currents with peak amplitudes ranging from 25 to 100 kA have been studied. Test set-up modifications were made considering the scale of the lightning damage and its potential proximity to specimen edges. Specimen geometry and anti-buckling guides were adjusted for each peak current to induce specimen failure at the lightning damage. The Compression After Lightning (CAL) strength was 28% lower than the pristine CAI strength even at a relatively low peak current of 25 kA. This study shows that the standard CAI test setup has the potential for CAL application, however, careful modifications are required depending on the peak amplitude of the applied lightning current waveform.

Experimental and Numerical Investigation of the In-Plane Compression of Corrugated Paperboard Panels

Finite element analysis (FEA) has been proven as a useful design tool to model corrugated paperboard boxes, and is capable of accurately predicting load capacity. The in-plane deformation, however, is usually significantly underpredicted. To investigate this discrepancy, a panel compression test jig, that implemented simply supported boundary conditions, was built to test individual panels. The panels were then modelled using non-linear FEA with a linear material model. The results show that the in-plane deformation was still underpredicted, but a general improvement was seen. Three discrepancies were identified. The first was that the panels showed an initial region of low stiffness that was not present in the FEA results. This was attributed to imperfections in the panels and jig. Secondly, the experimental results reported a lower stiffness than the FEA. Applying an initial imperfection in the shape of the first buckling mode shape was found to reduce the FEA stiffness. Thirdly, the panels showed a decrease in stiffness near failure, which was not seen in the FEA. A bi-linear material model was investigated and holds the potential to improve the results. Box compression tests were performed on a Regular Slotted Container (RSC) with the same dimensions as the tested panel. The box displaced 13.1 mm compared to 3.5 mm for the panel. There was an initial region of low stiffness, which accounted for 7 mm of displacement compared to 0.5 mm for the panels. Thus, box complexities such as horizontal creases should be included in finite element (FE) models to accurately predict the in-plane deformation, while a bi-linear (or any other non-linear) material model may be useful for panel compression.

New jig adapted for compression fatigue tests on composite materials

This paper presents a new adapted jig to perform quasi-static and fatigue compression tests based on the Combined Loading Compression (CLC), ASTM D6641 standard. This new jig is proposed to enable the performance of both static and fatigue tests accommodating various types of composite materials, different test standards, and coupons sizes. In order to validate the new testing jig, quasi-static and fatigue tests were performed in a composite with bidirectional carbon-fiber fabric type 8HS (Hardness Satin) with epoxy resin matrix. The numer 8 on 8HS means that during the production process, the warp yarn goes over seven before going under one fill yarn. The static and fatigue compressive stresses obtained for the 8HS composite were 643.2 MPa and 436.6 MPa respectively.

A Deep Learning Approach to Detect Anomalies in an Electric Power Steering System.

As anomaly detection for electrical power steering (EPS) systems has been centralized using model- and knowledge-based approaches, EPS system have become complex and more sophisticated, thereby requiring enhanced reliability and safety. Since most current detection methods rely on prior knowledge, it is difficult to identify new or previously unknown anomalies. In this paper, we propose a deep learning approach that consists of a two-stage process using an autoencoder and long short-term memory (LSTM) to detect anomalies in EPS sensor data. First, we train our model on EPS data by employing an autoencoder to extract features and compress them into a latent representation. The compressed features are fed into the LSTM network to capture any correlated dependencies between features, which are then reconstructed as output. An anomaly score is used to detect anomalies based on the reconstruction loss of the output. The effectiveness of our proposed approach is demonstrated by collecting sample data from an experiment using an EPS test jig. The comparison results indicate that our proposed model performs better in detecting anomalies, with an accuracy of 0.99 and a higher area under the receiver operating characteristic curve than other methods providing a valuable tool for anomaly detection in EPS.

Tensile Testing Jig Unit for Foams and Foam-Cored Fiber-Reinforced Plastic Sandwich Composites

Tensile Testing Jig Unit for Foams and Foam-Cored Fiber-Reinforced Plastic Sandwich Composites

Experimental investigation on effect of accelerated speed and rotor material on life of implantable micro-infusion pump tubing

Peristaltic pumps have been put to use in various biomedical applications like devices for the transfer of body fluids as well as devices for controlled release of medication, including implantable infusion pumps. Out of the various components of a peristaltic pump, tubing is considered the most vulnerable part. This study focuses on the performance of Silicone micro-pump tubing used in such an implantable drug delivery device. Long-term implantable medical devices are expected to be operational for about 10 years. But experimental testing of the reliability of components under normal working speeds are time-consuming and thus delays the product development cycle. While simulating the conditions in the laboratory under accelerated speeds, the effect of increasing the speed must be accounted. In this study, the effect of accelerated speed and rotor material on pump tubing life is investigated. A test jig is developed which simulates the running conditions of the infusion pump for long-duration operation. Different rotor speeds and material configurations are investigated to obtain their effect on long-duration performance. Thermal effects on the roller junctions are studied and found that the Delrin silicone combination has twice the rise in junction temperature than the titanium silicone combination. The failure modes are inspected using microstructure analysis and the best configuration is identified.

Biomechanical Evaluation of 2 Common Approaches for Total Elbow Arthroplasty: Triceps Tongue Compared With Triceps Reflecting

We hypothesize that the triceps tongue approach will be equivalent in strength to the triceps reflecting approach in load to failure following a cyclic preload. Seven paired fresh-frozen cadaveric arms were dissected using the triceps reflecting approach or triceps tongue approach to the posterior elbow. The triceps was then repaired in each specimen, and the elbows were placed in a testing jig. Elbows were preloaded in a cyclic fashion at 5 lbs (2.3 kgf) for 200 cycles in flexion/extension, followed by load to failure. The stiffness and ultimate failure strength for each specimen were determined. We defined ultimate failure as gapping in the suture construct of 4 mm or suture breakage. One of the triceps tongue specimens was excluded due to a testing error, resulting in 6 elbows in this group. There were no tendon repair failures during the cyclic preload. The median ultimate failure of the reflecting group occurred at 65 pounds, compared to 115 pounds in the tongue group. This was significantly different. The reflecting approach consistently failed along the entire bone-tendon interface. The tongue approach failed at the proximal repair site in 4 of 6 specimens, while the longitudinal aspect of the tendon repair remained intact. Following a cyclic preload of 5 lbs for 200 cycles, the triceps tongue repair is stronger than triceps reflecting in ultimate failure. The mode of failure of triceps tongue repair may be superior to that of triceps reflecting. This study may help guide surgeons when choosing a "triceps off" approach to total elbow arthroplasty.

An experimental study on vapor transport of a hollow fiber membrane module for humidification in proton exchange membrane fuel cells

Water management is key in the optimization of proton exchange membrane fuel cell performance and durability. Humidifiers can be used to provide water vapor to cathode air, ensuring the proper operation of proton exchange membrane fuel cells. In this study, water vapor transport characteristics of hollow fiber membrane modules were investigated in shell-tube humidifiers under isothermal conditions, using two different test jig constructions: a convection jig and a diffusion jig. The mass transfer rate of water vapor was evaluated via the impact of various operating parameters, including temperature, flow rate, pressure, and relative humidity of inlet wet air, flow arrangements, and surface area of the tube side. The result was presented by the water vapor transport rate from wet air flow to dry air flow across the hollow fiber membrane. It was found that humidification performance could be improved with higher operating temperature, flow rate, and relative humidity of inlet wet air, lower pressure, larger membrane surface area, higher convection effect, and substituting co-current with counter-current flow configuration.

Contact Compliance Based Visual Feedback for Tool Alignment in Robot Assisted Bone Drilling.

In recent decades, robot-assisted surgery has been proven superior at providing more accurate outcomes than the conventional one, particularly in minimally invasive procedures. However, there are still limitations to these kinds of surgical robots. Accurate bone drilling on the steep and hard surface of cortical bone is still challenging. The issues of slipping away from the target entry point on the bone surface and subsequently deviating from the desired path are still not completely solved. Therefore, in this paper, a force control is proposed to accompany the resolved motion rate controller in a handheld orthopedic robot system. The force control makes it possible to adjust the contact compliance of the drill to the bone surface. With the proper contact compliance, the drill can be prevented from deflecting in contact with the bone surface, and will eventually be directed to the target entry point. The experiments on test jig and vertebra phantom also show that the robot under the proposed contact compliance visual feedback control structure could produce better usability positioning accuracy under various contact disturbances than its counterpart.