Adjustable Mounting Research Articles

Reliability of cervicocephalic sense of force

Cervicocephalic proprioception (CCP) is an important assessment item for people with a range of clinical conditions, where reduced CCP is associated with neck pain and imbalance. Reliability has been established for a range of positional and movements tests, but there is limited data regarding sense of force, particularly across three planes of movement. The current test–retest study assessed reliability when evaluating sense of force in healthy adults (8 males, 6 females, mean age 31.50 years [SD 10.14]) over two sessions, 4–7 days apart. A force matching protocol was used to evaluate reliability of absolute error (AE), constant error (CE), and variable error (VE) for 10 % and 25 % maximal voluntary contraction (MVC) target forces for flexion, extension, lateral flexion, and rotation. Participants were strapped to a chair to limit trunk movement and data was captured using a compressive force transducer fixed to an adjustable wall mount. Six trials were performed for each contraction-type, totaling 72 submaximal MVCs per session. ICC estimates for AE (0.15–0.77), CE (0.01–0.85), and VE (0.00–0.83) were varied and confidence intervals were mostly wide. Considering lower limits of confidence intervals, CE had best reliability values generally, but more specifically the most reliable contraction type and movement was 25 % MVC flexion (ICC 0.85, confidence interval 0.54–0.95). This study found that reliability for sense of force testing was dependent upon contraction, type of error, and target force utilized. Further reliability analysis should be performed when applying this test to measure validity outcomes in clinical populations.

A Low-Voltage, High-Force Capacity Electroadhesive Clutch Based on Ionoelastomer Heterojunctions.

Electroadhesive devices with dielectric films can electrically program changes in stiffness and adhesion, but require hundreds of volts and are subject to failure by dielectric breakdown. Recent work on ionoelastomer heterojunctions has enabled reversible electroadhesion with low voltages, but these materials exhibit limited force capacities and high detachment forces. It is a grand challenge to engineer electroadhesives with large force capacities and programmable detachment at low voltages (<10V). In this work, tough ionoelastomer/metal mesh composites with low surface energies are synthesized and surface roughness is controlled to realize sub-ten-volt clutches that are small, strong, and easily detachable. Models based on fracture and contact mechanics explain how clutch compliance and surface texture affect force capacity and contact area, which is validated over different geometries and voltages. These ionoelastomer clutches outperform the best existing electroadhesive clutches by fivefold in force capacity per unit area (102 N cm-2 ), with a 40-fold reduction in operating voltage (± 7.5V). Finally, the ability of the ionoelastomer clutches to resist bending moments in a finger wearable and as a reversible adhesive in an adjustable phone mount is demonstrated.

Imaging fine structures of the human trabecular meshwork in vivo using a custom design goniolens and OCT gonioscopy.

The trabecular meshwork (TM), located within the iridocorneal angle, is a target for many glaucoma treatments aimed at controlling intraocular pressure. However, structural variations between individuals are poorly understood. We propose a newly designed gonioscopic lens optimized for high-resolution imaging to image fine structures of the human TM in vivo. The body of the new lens is index-matched to the human cornea and includes a choice of two gonioscopic mirrors (59° and 63°) and matching air-spaced doublets placed on the anterior surface of the goniolens. The new design allows a diffraction-limited image plane at the iridocorneal angle structures. The goniolens design was built and then placed on the subjectś eyes coupled to the cornea with goniogel and a 3D adjustable mount. Images were obtained using a commercially available OCT device (Heidelberg Spectralis). The optical resolution was measured in a model eye as 40.32 and 45.25 cy/mm respectively for each mirror angle. In humans, dense OCT scans with minimum spacing oriented tangential to the iris and ICA were performed on 7 healthy subjects (23-73 yrs). The TM was successfully imaged in all subjects. The custom goniolens improved the contrast of the uveoscleral meshwork structures and corneoscleral meshwork revealing limbus parallel striations, not visible with previous goniolens designs. Transverse OCT images were constructed along the segmentation line, providing an enface image of the TM structures including corneoscleral beams, previously only imaged in vivo using custom adaptive optics systems.

Intravenous Fluid Resuscitation Capabilities in Simulated Reduced Gravity.

BACKGROUND: Critical care for exploration space missions may require intravenous (IV) fluid resuscitation therapy. Resource constraints may limit availability of standard, Earth-based infusion technologies. The effect of variable acceleration on infusion flow rates using simple fluid resuscitation supplies was investigated.METHODS: Infusions of water or blood analog (40% glycerol) from a 1 L IV bag were performed using pressure bag augmentation at 0, 150, or 300 mmHg. The solution bag rested on an adjustable mount, configured to different heights to simulate relevant gravitational accelerations (1 G, Martian G, lunar G, and 0 G). The bag emptied through an IV line with a 14- or 20-gauge angiocath into a 3-mmHg venous pressure reservoir. Flow rates were measured using an in-line flow probe. Three determinations were made for each test condition.RESULTS: Temporal flow rate data for all test conditions displayed one-phase exponential decay. At 300 mmHg pressurization, maximum infusion rates ranged from 92-222 mL ⋅ min-1 for water and from 21-49 mL ⋅ min-1 for blood analog. All reduced gravity conditions had significantly longer infusion times in comparison to 1 G for both test solutions.DISCUSSION: Reduced acceleration significantly altered flow rates and infusion times for fluid resuscitation. Fluid resuscitation protocols specify a desired volume to infuse for a target time (e.g., 20-30 mL ⋅ min-1 for a 75-kg adult). This data demonstrates that this protocol parameter can be achieved with infusion pressure bag augmentation alone and provides information for the refinement of fluid resuscitation protocols for exploration space missions.Pantalos GM, Heidel JS, Jain IM, Warner SE, Barefoot TL, Baker RO, Hailey M. Intravenous fluid resuscitation capabilities in simulated reduced gravity. Aerosp Med Hum Perform. 2023; 94(8):596-603.

447 Characterization of the human iridocorneal angle in vivo using a custom design goniolens with OCT gonioscopy

OBJECTIVES/GOALS: The trabecular meshwork (TM) and Schlemm’s canal (SC), located within the iridocorneal angle (ICA), form the main outflow pathway and a major target for glaucoma treatments. We characterized the human ICA in vivo with Optical Coherence Tomography (OCT) imaging using a customized goniolens and a commercial OCT device (Heidelberg Spectralis). METHODS/STUDY POPULATION: Imaging these structures is difficult due to the optical limitations of imaging through the cornea at high angles. Therefore, a clinical gonioscopy lens was modified with a 12mm plano-convex lens placed on its anterior surface to focus light on the ICA structures, and capture returning light. Each subjects’ eye was anesthetized with 1 drop of Proparacaine 0.5%. The goniolens was coupled to the eye with gonio-gel and it was held by a 3D adjustable mount. OCT volume scans were acquired on 10 healthy subjects. The linear polarization of the OCT was rotated with a half-waveplate to measure dependence of the ICA landmarks on polarization orientation. RESULTS/ANTICIPATED RESULTS: The TM was seen in 9 of 10 subjects. Polarization rotation modified the brightness of the band of extracanalicular limbal lamina (BELL) and corneoscleral bands due to the birefringent nature of the collagenous structures, increasing the contrast of SC. SC width was 99 ± 20µm varying in size over space, including a subject with SC narrowing in the inferior-temporal quadrant. DISCUSSION/SIGNIFICANCE: This clinically suitable gonioscopic OCT approach has successfully been used to image the human ICA in 3D in vivo, providing detailed characterization of the TM and SC as well as enhancing their contrast against their birefringent backgrounds by rotating the polarization of the imaging beam.

Model-based design of a novel modular mounting system: Light, compact, and efficient

Two-stage mounting systems applied in ships are expected to be light in weight, compact in installation space, and efficient in vibration isolation performance at the same time, which largely increases the engineering complexity. In this paper, analytical models of a two-stage mounting system with flexible and rigid intermediate mass are proposed to compare the vibration isolation effectiveness (VIE) performance and the influences of system parameters with the rigid intermediate mass on VIE are introduced. Based on the analysis results, an integrated adjustable two-stage mounting module is designed. Compared to the traditional floating raft mounting system with flexible intermediate mass, this two-stage mounting module can be arranged in a more compact structure space with greatly reduced size and weight. Furthermore, a novel modular mounting system prototype is proposed and manufactured based on several two-stage mounting modules and real-time behavior monitoring and controlling subsystem. The testing results verify the compatibility of the module design and the behavior monitoring and controlling system. The modular mounting system also exhibits excellent VIE performance combined with the advantage of compact intermediate mass size, lightweight, and automatic behavior monitoring and controlling.

Characterization of the human iridocorneal angle in vivo using a custom design goniolens with OCT gonioscopy.

Intraocular pressure (IOP) is the only modifiable risk factor for glaucoma progression, and many treatments target the trabecular meshwork (TM). Imaging this region in vivo is challenging due to optical limitations of imaging through the cornea at high angles. We propose a gonioscopic OCT approach using a custom goniolens and a commercially available OCT device to improve imaging of the TM, Schlemm's canal (SC) and adjacent structures within the iridocorneal angle (ICA). The goniolens is modified with a plano-convex focusing lens and placed on the eye optically mated with goniogel and aided by a 3D adjustable mount. Gonioscopic OCT volume scans are acquired to image SC. Transverse enface images allowed measurements of SC over a 45° section of the ICA for the first time and revealed locations of SC narrowing. The band of extracanalicular limbal lamina and corneoscleral bands were imaged in most subjects and these bands were confirmed using exterior OCT imaging. The polarization dependence of the visibility of these structures is studied by polarization rotation the OCT beam with a half-wave plate, allowing increased contrast of SC. Gonioscopic OCT has successfully been used to image the human ICA in 3D in vivo. This approach provides more detailed characterization of the TM and SC, enhancing their contrast against their birefringent backgrounds.

Suppression of Frequency Modulation to Amplitude Modulation Conversion with Modified Group Velocity Dispersion Compensation Device in the Front End of High-Power Lasers

The group velocity dispersion (GVD) occurring in the front end of high-power lasers is one of the primary factors leading to the conversion of frequency modulation (FM) to amplitude modulation (AM). In this paper, we propose a modified, active, closed-loop feedback compensation device for GVD-induced FM–AM conversion, using a two-dimensional, electric, adjustable mirror mount and parallel grating pair to improve the long-term stability, efficiency of adjustment, and accuracy of compensation. Experimental results of a 12 h FM–AM depth test revealed that the depth varied between 2.28% and 5.22%. Moreover, we formulated a mathematical relationship between the dispersion parameters and temperature in optical fibers to analyze the intrinsic effect of temperature on FM–AM. The related simulation and experimental results consistently validated the quantitative relationship between the temperature and FM–AM depth.

An adjustable mounting rack or an additional PV panel? Cost and environmental analysis of a photovoltaic installation on a household: A case study in Poland

Since increasing electricity consumption in developing countries is observed, the measures that can reduce electricity bills are of key importance for individuals. One of them is the assemblage of PV installation of their households. The fundamental parameters that may be adjusted are the number of PV panels and the change in their orientation towards the roof plane (tilt and azimuth angles). The paper presents the first study aimed at conducting a quantitative economic and environmental analysis that allows one to compare these two choices and provide valuable findings based on the specific case of a single-family house in Poland. Results indicate that NPV is higher in the case of an additional PV panel by EUR 354 per 30 years. However, an adjustable mounting rack installation provides a higher reduction of carbon emissions (by 1.2 Mg CO2/30 years). Additionally, the study provides maps that may be used to compare the economic and environmental efficiency for various orientations of roofs and PV installations throughout the country. The outcomes are mainly relevant for the residential sector because they provide information that supports the decision-making processes in the context of changes in PV installations and selecting support mechanism for renewable sources.

Development of Vibration Isolator Magnetorheological Elastomer Based

Most of the vibration isolator has fixed stiffness, such as a passive vehicle mounting system. This article presents the development of the adjustable stiffness engine mounting magnetorheological elastomers (MREs) based to reduce vibration. The development of MREs vibration isolator is to design of engine mounting first step, for next step is to simulate the electromagnetic circuit. The housing material selection and MREs thickness were considered to provide ample and uniform magnetic fields to change the stiffness. The innovative magnetic circuit design includes the type and size of the wire and the number of turns of the coil to obtain the best magnetic fields to eliminate vibration. Finite Element Method Magnetics (FEMM) software was used to show the effectiveness of the electromagnetic circuit to generate magnetic fields through the MREs. Finally, the varies current input influence to the MREs vibration isolator is investigated. The higher current input is more useful to eliminate vibration using MREs isolator system.

Development of vibration isolator using magnetorheological elastomer

Many vibration isolators, for example, passive vehicle mounting devices, have fixed rigidity. This article presents the development of an adjustable stiffness engine mount based on the magnetorheological elastomer (MRE) to reduce engine vibration. The development of the first MREs vibration isolator was to design the engine mounting, and then to simulate a magnetic circuit. The choice of housing material and the thickness of the MRE is considered to complement a sufficient and uniform magnetic field to change the stiffness. The innovative magnetic circuit design includes the type and size of the wire and the number of turns of the coil for optimal magnetic field. Finite Element Method Magnetics (FEMM) software was used to demonstrate the effectiveness of electromagnetic circuits in generating magnetic fields through MRE samples. Finally, influenced by the various current input in the coil, the performance of the MRE vibration isolator is investigated. The input electric current whose value increases is more useful to change the increased stiffness value of the MRE-based isolator system.

激光系统中可调节支撑镜架的结构稳定性研究

激光系统中可调节支撑镜架的结构稳定性研究

Adjustable flexure mount to compensate for deformation of an optic surface

An adjustable mounting structure is proposed to compensate for surface deformation of a mirror caused by the assembly process. The mount adopts a six-point support based on the kinematic mount principle. Three of the support points are adjustable, and they are moved along the axial direction by actuators. Surface deformation is expressed by Zernike coefficients in this paper, and a sensitivity matrix of the surface deformation is established by varying the unit displacement of each adjustment support point and getting the corresponding Zernike coefficient changes. The surface deformation is measured, and the compensation adjustment of each adjustable support point is then obtained by anti-sensitivity calculation. Finally, the feasibility of present support structure design and surface figure compensating method are verified by experiments. The experimental results show that the present structure and method could significantly reduce the surface deformation caused by the assembly process. The surface deformation is 4.6 nm RMS after assembly and it is decreased to 1.3 nm RMS after four iterations of compensation, which is close to the 1.1 nm RMS after optical polishing.

A self-calibration rotational stitching method for precision measurement of revolving surfaces

When measuring revolving objects, it is often desired to obtain not only the geometrical form of the workpiece, but also the topography of the surface, as they both affect the performance of the part. However, holistic measurement of the entire three-dimensional surface of a revolving part is challenging since most surface measurement instruments only have limited measurement ability, where the bottom and the side surfaces cannot be measured. One solution to obtain geometrical form and surface topography information simultaneously is to add a precision axis to rotate the object while performing surface topography measurement. However, this solution requires a high-cost precision rotation stage and adjustable mounting and alignment aids. Moreover, errors in the rotation will be added to the measurement result, which can be difficult to compensate. Stitching is a method often used for measuring revolving surfaces without the need for precision motion axes, as the method is applied at the software level, and errors in the rotation can be compensated by the stitching algorithm. Nevertheless, the overall accuracy of stitching is limited when the number of sub-surfaces is large, since the measurement and stitching error accumulate along the stitching chain. In this paper, a self-calibration rotational stitching method is presented which can compensate for the accumulated error. The self-calibration method utilises the inherent nature of a revolving surface and compensates for the registration error by aligning the last dataset with the first dataset. The proposed method is demonstrated by measuring grinding wheels with a coherence scanning interferometer and simultaneously rotating the grinding wheels with a low-cost stepper-motor. It is demonstrated that the proposed stitching measurement method is effective in compensating for accumulated registration error. The proposed self-calibration rotational stitching method can be easily extended to a wide range of applications for measuring revolving surfaces using various measuring instruments.

Development of novel adjustable focus head mount display for concurrent image-guided treatment applications

Purpose: A conventional see-through head mount display contains many optical lenses, which can be problematic in image-guided treatment applications due to its size, weight, structure, and focus limitation. Therefore, we have designed a new type of see-through head mount display with a reduced number of optical lenses and an adequate optical resolution that can be utilized for image-guided treatment applications.Materials and methods: A new type of adjustable focus head mount display with expanded virtual images and an external treatment space that can be provided to the eyes of a user by enlarging the images of a small display is designed and investigated in this study. This type of head mount display can be used in image-guided treatment applications because of the dual paths of imaging and treatment from the optical systems. Therefore, this system with an adjustable focus function can aid doctors in obtaining images for the treatment of the eyes of patients because every patient has a unique pupil size.Results: The results of the adjustable focus see-through head mount display showed distortion values of +0.36% in the +1 diopter location and −0.55% in the −4 diopter location, and there are less significant modulation transfer function differences within the ±5 diopter locations.Conclusions: Low optical distortions within ±0.5 diopters can help doctors image the eye conditions of patients through fewer image processing techniques. Therefore, the designed adjustable focus head mount display can provide low optical aberrations and high optical modulation transfer function resolutions for image-guided treatment applications.

ADJUSTABLE MOUNTING JIG FOR MEAN VALUE ARTICULATOR

An articulator is a mechanical instrument that represents the temporomandibular joints and jaws, to which maxillary and mandibular casts may be attached to simulate some or all mandibular movement. During attaching or mounting the casts, problems such as shifting of cast assembly due to compression of modelling stone or waxes. Also shifting of rubberband used for adjusting the occlusal plane during mounting. In addition, errors in transferring maxillo-mandibular relation to articulator are reproduced as errors in tooth relation and tooth movement. This article introduces amethod to overcome these errors and inaccuracies during mounting in mean value articulator adjustable mounting jig.

Design Considerations and Measured Performance of Nontracked Mirror-Augmented Photovoltaics

Costs associated with conventional photovoltaic (PV) installations (module manufacturing, mounts, wiring and installation labor, etc.) scale linearly with system area, and prudent design practices for increasing the light harvesting may significantly enhance the power output per unit area and cost per watt. The use of PV modules that have been augmented by the addition of a solar mirror provides an opportunity to improve light harvesting of a PV module and cost-per-watt considerations if the mirror is less expensive than the relative increase in power. In order to harvest greater insolation, an optimized design configuration between a flat-panel module and mirror is necessary for a fixed (nontracked) mirror-augmented photovoltaic (MAPV) system. A series of irradiance and energy harvest calculations were developed to screen various MAPV design configurations. We employed optical ray-tracing simulations to determine irradiance nonuniformities on the fixed MAPV system. The simulated results are compared with outdoor experimental field trial results. Over a three-month period of study, the fixed MAPV system produced 12% more power than an equivalent nonaugmented panel. An adjustable angle mounting system known as “time machine” was used to estimate yearly power production by adjusting the relative position of the MAPV system to represent varying times of the year. Current--voltage ( I – V ) curve tracing of test modules was performed during the field trials on augmented and nonaugmented modules for comparison. The experimental time machine result is in agreement with the irradiance simulation, which shows a gullwing curve of annual power output with peak production on the equinoxes and reduced production on the solstices.

Neutron gamma fraction imaging: Detection, location and identification of neutron sources

In this paper imaging of neutron sources and identification and separation of a neutron source from another neutron source is described. The system is based upon organic liquid scintillator detector, tungsten collimator, bespoke fast digitiser and adjustable equatorial mount. Three environments have been investigated with this setup corresponding to an AmBe neutron source, a 252Cf neutron source and both sources together separated in space. In each case, events are detected, digitised, discriminated and radiation images plotted corresponding to the area investigated. The visualised neutron count distributions clearly locate the neutron source and, relative gamma to neutron (or neutron to gamma) fraction images aid in discriminating AmBe sources from 252Cf source. The measurements were performed in the low scatter facility of the National Physical Laboratory, Teddington, UK.

Characterization of intracochlear rupture forces in fresh human cadaveric cochleae.

To develop a method to measure the forces required for a probe to translocate from the scala tympani (ST) to the scala vestibuli (SV) in fresh human cochleae. Translocation of cochlear implant electrodes from the ST to the SV may lead to suboptimal audiologic outcomes. Prior work investigating the rupture forces of human intracochlear membranes comes from a single study conducted on isolated ex vivo cadaveric specimens. Fresh (postmortem <120 h), nonfixed, never-frozen human temporal bones underwent preparation consisting of surgical isolation of the cochleae and exposure of the osseous spiral lamina, basilar membrane, and Reissner's membrane complex by removing bone covering the ST and the SV. Each isolated cochlea was mounted to a force sensor using an adjustable mounting platform. A 300-μm-diameter ball-tipped probe was attached to a piezoelectric linear motor and advanced at 1 mm/s from the ST to the SV while recording force from the load cell concurrent with video. Ten specimens were successfully exposed and analyzed. The range of rupture forces was 42 to 122 mN, with a mean of 88 mN. Nine of the 10 specimens failed via simple puncture, whereas one failed by being avulsed from its medial attachment. Using a novel technique, we report the forces required to translocate a model of an electrode from the ST to the SV. Correlation to human perceptual ability is necessary to determine if a surgeon can detect such translocation during cochlear implant surgery.

An accuracy assessment of different rigid body image registration methods and robotic couch positional corrections using a novel phantom

Image guided radiotherapy (IGRT) using cone beam computed tomography (CBCT) images greatly reduces interfractional patient positional uncertainties. An understanding of uncertainties in the IGRT process itself is essential to ensure appropriate use of this technology. The purpose of this study was to develop a phantom capable of assessing the accuracy of IGRT hardware and software including a 6 degrees of freedom patient positioning system and to investigate the accuracy of the Elekta XVI system in combination with the HexaPOD robotic treatment couch top. The constructed phantom enabled verification of the three automatic rigid body registrations (gray value, bone, seed) available in the Elekta XVI software and includes an adjustable mount that introduces known rotational offsets to the phantom from its reference position. Repeated positioning of the phantom was undertaken to assess phantom rotational accuracy. Using this phantom the accuracy of the XVI registration algorithms was assessed considering CBCT hardware factors and image resolution together with the residual error in the overall image guidance process when positional corrections were performed through the HexaPOD couch system. The phantom positioning was found to be within 0.04 (σ = 0.12)°, 0.02 (σ = 0.13)°, and -0.03 (σ = 0.06)° in X, Y, and Z directions, respectively, enabling assessment of IGRT with a 6 degrees of freedom patient positioning system. The gray value registration algorithm showed the least error in calculated offsets with maximum mean difference of -0.2(σ = 0.4) mm in translational and -0.1(σ = 0.1)° in rotational directions for all image resolutions. Bone and seed registration were found to be sensitive to CBCT image resolution. Seed registration was found to be most sensitive demonstrating a maximum mean error of -0.3(σ = 0.9) mm and -1.4(σ = 1.7)° in translational and rotational directions over low resolution images, and this is reduced to -0.1(σ = 0.2) mm and -0.1(σ = 0.79)° using high resolution images. The phantom, capable of rotating independently about three orthogonal axes was successfully used to assess the accuracy of an IGRT system considering 6 degrees of freedom. The overall residual error in the image guidance process of XVI in combination with the HexaPOD couch was demonstrated to be less than 0.3 mm and 0.3° in translational and rotational directions when using the gray value registration with high resolution CBCT images. However, the residual error, especially in rotational directions, may increase when the seed registration is used with low resolution images.