Hand-held Tools Research Articles

Energy Absorbency and Impact Resistance of D3O® Materials Under Dynamic Impact Loadings

Hand-held power tools, such as percussive riveting tools, produce vibrational forces that are transmitted through the hands, arms, and elbows. These vibrational forces may be responsible for the causation of short and long-term neuronal and/or vascular diseases. Personal protective materials are available commercially, some of which are used during the operation of percussive power tools (e.g., anti-vibration gloves). In previous studies, D3O^® materials showed a greater absorption of impact energy in low-velocity static impact testing compared to conventional materials. In this study, D3O^® materials were tested under dynamic impact loadings to evaluate resistance to impact characteristics to assess the adequacy of an ergonomic intervention using D3O^® materials. An experiment was performed to evaluate material resistance to impact by evaluating the peak load values with different precompression magnitudes and loading frequencies. D3O^® materials showed that compression magnitude was a statistically significant factor (<i>p</i> = 0.00) affecting the peak load value compared to loading frequency, which had little to no effect when tested under 14 Hz or less. As peak loads increase, the resistance to impact loading decreases and energy transmission increases. D3O^® back protector (DBP) and D3O^® Rifle Harness (DRH) exhibited lower peak values compared to D3O^® Recoil Pad (DRP) material. D3O^® materials may be considered to be utilized in a riveting and bucking intervention to reduce vibrational forces from percussive tools in a dynamic aircraft manufacturing environment.

Work-related head injury and industry sectors in Finland: causes and circumstances

ObjectiveDespite the continuous development of occupational safety, the prevalence of work-related head injuries is excessive. To promote prevention, we conducted a study evaluating the risks and pathways that precede head injuries in different economic activity sectors.MethodsIn Finland, more than 90% of employees are covered by inclusive statutory workers’ compensation. We obtained data on occupational head injuries in 2010–2017 from an insurance company database. The European Statistics on Accidents at Work (ESAW) variables represented the characteristics of the accidents and the injury. We analysed the risk factors, contributing events and injury mechanisms in 20 industry sectors, based on the Statistical Classification of Economic Activities in the European Community (NACE).ResultsIn the 32,898 cases, the most commonly affected area was the eyes (49.6%). The highest incidence of head injuries was in construction (15.7 per 1000 insurance years). Construction, manufacturing, and human health and social work activities stood out due to their distinctive ESAW category counts. ‘Working with hand-held tools’ [risk ratio (RR) 2.23, 95% confidence interval (CI) 2.14–2.32] in construction and ‘operating machines’ (RR 3.32, 95% CI 3.01–3.66) and ‘working with hand-held tools’ (1.99, 1.91–2.07) in manufacturing predicted head injury. The risk related to parameters of violence and threats in health and social work activities was nearly ninefold the risk of other sectors.ConclusionThe risks and pathways preceding head injuries varied considerably. The highest head injury rates were in construction and manufacturing. Violence emerged as a major risk factor in human health and social work activities.

Assessing product suitability for remanufacturing – a case study of a handheld battery-driven assembly tool

Assessing product suitability for remanufacturing – a case study of a handheld battery-driven assembly tool

Management of stenosing flexor tenosynovitis in primary care.

Management of stenosing flexor tenosynovitis in primary care.

Data Alignment Design for Robotic Programming by Demonstration Based on IMU and Optical Tracker

This study proposes a data alignment design for sensor fusion of an optical target (OT) and an inertial measurement unit (IMU) to track the trajectory of a handheld tool for robot programming by demonstration (PbD). A novel method is proposed for coordinate and temporal alignment between the OT and the IMU sensor to increase the tracking accuracy. The IMU measurements are aligned with the corresponding angular velocities and accelerations derived from the OT to calibrate the IMU-OT relationship. Global and local optimizations are combined to reduce the computation time for the temporal alignment and coordinate calibration. Experimental results show that the proposed method provides improved calibration results with shorter calculation time compared with two existent methods. The sensor fusion experiments verify the accuracy of trajectory tracking of 1.3mm using the calibration result, an improvement from 1.4mm of the data alignment using ruler measurement. Integrated PbD experiments by using a 6-DOF manipulator were carried out to evaluate the proposed method. The manipulator imitated the hand motion of a bottle transfer task with the trajectory error of 0.66mm. Practical robotic experiments demonstrate that the method is suitable for robot programming applications.

Audiovisual integration of the dynamic hand-held tool at different stimulus intensities in aging.

Introduction: In comparison to the audiovisual integration of younger adults, the same process appears more complex and unstable in older adults. Previous research has found that stimulus intensity is one of the most important factors influencing audiovisual integration. Methods: The present study compared differences in audiovisual integration between older and younger adults using dynamic hand-held tool stimuli, such as holding a hammer hitting the floor. Meanwhile, the effects of stimulus intensity on audiovisual integration were compared. The intensity of the visual and auditory stimuli was regulated by modulating the contrast level and sound pressure level. Results: Behavioral results showed that both older and younger adults responded faster and with higher hit rates to audiovisual stimuli than to visual and auditory stimuli. Further results of event-related potentials (ERPs) revealed that during the early stage of 60-100 ms, in the low-intensity condition, audiovisual integration of the anterior brain region was greater in older adults than in younger adults; however, in the high-intensity condition, audiovisual integration of the right hemisphere region was greater in younger adults than in older adults. Moreover, audiovisual integration was greater in the low-intensity condition than in the high-intensity condition in older adults during the 60-100 ms, 120-160 ms, and 220-260 ms periods, showing inverse effectiveness. However, there was no difference in the audiovisual integration of younger adults across different intensity conditions. Discussion: The results suggested that there was an age-related dissociation between high- and low-intensity conditions with audiovisual integration of the dynamic hand-held tool stimulus. Older adults showed greater audiovisual integration in the lower intensity condition, which may be due to the activation of compensatory mechanisms.

Surgery for subacromial impingement syndrome and occupational biomechanical risk factors in a 16-year prospective study among male construction workers.

The aim of this study was to assess the association between occupational biomechanical exposures and the occurrence of surgical treatment for subacromial impingement syndrome (SIS). A cohort of 220 295 male constructions workers who participated in a national occupational health surveillance program (1971-1993) were examined prospectively over a 16-year follow-up period (2001-2016) for surgically treated SIS. Worker job title, smoking status, height, weight, and age were registered on health examination. Job titles were mapped to 21 occupational groups based on tasks and training. A job exposure matrix (JEM) was developed with exposure estimates for each occupational group. Surgical cases were determined through linkage with the Swedish national in- and outpatient registers. Poisson regression was used to assess the relative risks (RR) for each biomechanical exposure. The total incidence rate of surgically treated SIS over the 16-year observation period was 201.1 cases per 100 000 person-years. Increased risk was evident for workers exposed to upper-extremity loading (push/pull/lift) (RR 1.45-2.30), high hand grip force (RR 1.47-2.23), using handheld tools (RR 1.52-2.09), frequent work with hands above shoulders (RR 1.62-2.11), static work (RR 1.77-2.26), and hand-arm vibration (RR 1.78-2.13). There was an increased risk for SIS surgery for all occupational groups (construction trades) compared with white-collar workers (RR 1.56-2.61). Occupational upper-extremity load and posture exposures were associated with increased risk for surgical treatment of SIS, which underlines the need for reducing workplace exposures and early symptom detection in highly exposed occupational groups.

Association between extreme temperature exposure and occupational injuries among construction workers in Italy: An analysis of risk factors

Background/AimExtreme temperatures have impact on the health and occupational injuries. The construction sector is particularly exposed. This study aims to investigate the association between extreme temperatures and occupation injuries in this sector, getting an insight in the main accidents-related parameters. MethodsOccupational injuries in the construction sector, with characteristic of accidents, were retrieved from Italian compensation data during years 2014–2019. Air temperatures were derived from ERA5-land Copernicus dataset. A region based time-series analysis, in which an over-dispersed Poisson generalized linear regression model, accounting for potential non-linearity of the exposure- response curve and delayed effect, was applied, and followed by a meta-analysis of region-specific estimates to obtain a national estimate. The relative risk (RR) and attributable cases of work-related injuries for an increase in mean temperature above the 75th percentile (hot) and for a decrease below the 25th percentile (cold) were estimated, with effect modifications by different accidents-related parameters. ResultsThe study identified 184,936 construction occupational injuries. There was an overall significant effect for high temperatures (relative risk (RR) 1.216 (95% CI: (1.095–1.350))) and a protective one for low temperatures (RR 0.901 (95% CI: 0.843–0.963)). For high temperatures we estimated 3,142 (95% CI: 1,772–4,482) attributable cases during the studied period. RRs from 1.11 to 1.30 were found during heat waves days. Unqualified workers, as well as masons and plumbers, were found to be at risk at high temperatures. Construction, quarry and industrial sites were the risky working environments, as well as specific physical activities like working with hand-held tools, operating with machine and handling of objects. Contact with sharp, pointed, rough, coarse ‘Material Agent’ were the more risky mode of injury in hot conditions. ConclusionsPrevention policies are needed to reduce the exposure to high temperatures of construction workers. Such policies will become a critical issue considering climate change.

Team O2AC at the world robot summit 2020: towards jigless, high-precision assembly

High-mix, low-volume assembly has been a long-standing challenge for robot systems. We present a complete 2-armed robot system with general-purpose grippers and hand-held tools, which can perform assembly for a wide variety of objects with tight tolerances. The complete source code and 3D-printed-part designs are available for download and can be executed in simulation and with physical robots using a regular desktop computer. Furthermore, we present the designs of multiple tools which can be grasped and used by the robots in a human-like fashion. The system uses no parts-specific jigs and grippers to be applied to many different parts. It achieves high precision and reliability by using the environment and gripper surfaces to position the grasped objects. The system obtained 3rd place and the Japanese Society for Artificial Intelligence Award at the World Robot Summit 2020 Assembly Challenge.

Imbalance vibration suppression for asymmetric rotors via an enhanced automatic dynamic balancer

Automatic dynamic balancer (ADB) is a passive ball-bearing type of vibration control device and has been applied successfully on some rotating machineries, i.e., hand-held machine tools and optical disk drives. Recently, an enhanced automatic dynamic balancer (EADB) has been developed to extend the capability of the ADB and to achieve a perfect-balancing condition in a wider rotor speed operation range. However, the EADB cannot be applied directly to the imbalance vibration suppression for asymmetric rotors since a multi-frequency whirling limit cycle in the asymmetrically supported rotor/ADB systems prevents the assumed solution of a single-frequency whirling limit cycle for the symmetric supported rotor/ADB systems. To address the aforementioned limitation, this paper proposes an imbalance vibration suppression method for asymmetric rotors via an EADB, which can achieve rotor perfect balancing condition in a wider operation range. The non-autonomous equations of motion for an asymmetrically supported planar rotor with an EADB system is established via Lagrange's method. The perfect-balancing equilibrium of the system is solved analytically, and the multi-frequency whirling limit cycle is obtained via a multi-tone harmonic balance method whose tones are predetermined by the matrix pencil method. To destabilize the multi-frequency whirling limit cycle and to guarantee the stable perfect balancing conditions for an asymmetric rotor with an EADB, a numerical continuation method is adopted to design parameters for the EADB. The stability analysis of the perfect-balancing equilibrium and the multi-frequency whirling limit cycle are conducted by Floquet theory. The enlarged unstable whirling limit cycle solution proves the effectiveness of the proposed method.

Accuracy and Precision in Urban Forestry Tools for Estimating Total Tree Height

Background: Urban tree inventories are fundamental to the monitoring and management of urban forests. Various handheld tools and methods exist to conduct tree mensuration, ranging from the simple stick method to laser rangefinders. This study examines the accuracy and precision of the stick method, clinometer, and laser rangefinder, and introduces tree type (i.e., conifer versus broadleaf) comparisons of accuracy and precision. Methods: Measurements were taken from 127 trees comprised of 85 (66.9%) broadleaf and 42 (33.1%) coniferous trees. Trees were distributed across 4 urban land use types: park, golf course, street, and trail system. A drone-mounted measurement tape was used to determine true height. Results: Measured heights ranged from 4.67 m to 25.71 m (x̄ = 13.19 m). Measurements from the stick method yielded statistically similar results to both the rangefinder and clinometer methods. The methods had a Cronbach’s Alpha of 0.991 (N = 3). Accuracy was highest for the rangefinder and lowest for the stick method. Precision was greatest between the rangefinder and the clinometer. Root-meansquare error (RMSE) and percent error were highest for the stick method and broadleaf trees for all 3 measurement methods. Conclusions: The findings indicate greater accuracy and precision across all tools when measuring conifers. The rangefinder was similar in accuracy to the clinometer, with notable changes in accuracy when using the stick method.

Bamboo and rattan: Nature-based solutions for sustainable development

Bamboo and rattan: Nature-based solutions for sustainable development

Engineered Stone Fabrication Work Releases Volatile Organic Compounds Classified as Lung Irritants.

Engineered stones are often characterized for their crystalline silica content. Their organic composition, particularly that of the emissions generated during fabrication work using hand-held power tools, is relatively unexplored. We forensically screened the emissions from dry-cutting 12 engineered stone products in a test chamber for their organic composition by pyrolysis-gas chromatography-mass spectrometry (GC-MS) plus selected traditional capture and analysis techniques. Phthalic anhydride, which has a Respiratory Sensitization (RSEN) Notation by the American Conference of Governmental Industrial Hygienists (ACGIH), was the most common and abundant compound, at 26-85% of the total organic composition of engineered stone emissions. Benzaldehyde and styrene were also present in all twelve samples. During active cutting, the predominant volatile organic compound (VOC) emitted was styrene, with phthalic anhydride, benzene, ethylbenzene, and toluene also detected. These results have important health implications as styrene and phthalic anhydride are irritants to the respiratory tract. This study suggests a risk of concurrent exposure to high levels of respirable crystalline silica and organic lung irritants during engineered stone fabrication work.

Development of a portable device for preventing injuries due to a loss of grounding and broken neutral

Any discontinuity in the power cords of electrical devices can lead to electric shock, injury, and even death. This article presents a portable device that, when placed in the proximity of handheld tools, prevents such injuries. The principal operation of this device is based on electric and magnetic field meters and display segment LEDs. When the grounding conductor of a portable tool with a metal enclosure is broken, the electric field around it is increased. In the same way, when the neutral conductor is broken, the magnetic field is increased. The device detects any variations in electric or magnetic fields and displays a warning signal for alert.

Dermoscopy and skin imaging light sources: a comparison and review of spectral power distribution and color consistency.

.Significance: Dermoscopes incorporate light, polarizers, and optical magnification into a handheld tool that is commonly used by dermatologists to evaluate skin findings. Diagnostic accuracy is improved when dermoscopes are used, and some major artificial intelligence (AI) projects have been accomplished using dermocopic images. Color rendering consistency and fidelity are crucial for clinical diagnostics, AI, and image processing applications.Aim: With many devices available on the market, our objective was to measure the emission spectra of various dermoscopes, compare them with other light sources, and illustrate variations in reflected colors from images of a reference sample.Approach: A spectrometer measured the spectral power distribution (SPD) produced by four dermoscope models and three alternate light sources, illustrating differences in the emission spectra. Most dermoscopes use light-emitting diodes (LEDs), which are inconsistent when compared with one another. An LED was compared with halogen, xenon-arc, and daylight sources. Images of a micro ColorChecker were acquired from several sources, and three specific colors were selected to compare in CIELAB color space. Color consistency and color fidelity measured by color rendering index (CRI) and TM-30-18 graphical vectors show variation in saturation and chroma fidelity.Results: A marked degree of variation was observed in both the emission and reflected light coming from different dermoscopes and compared with other sources. The same chromophores appeared differently depending on the light source used.Conclusions: A lack of uniform illumination resulted in inconsistent image color and likely impacted metamerism and visibility of skin chromophores in real-world settings. Artificial light in skin examinations, especially LEDs, may present challenges for the visual separation of specific colors. Attention to LEDs SPD may be important, especially as the field increases dependency on machine/computer vision.

A Study of Improving Independent Walking Outcomes in Children Who Are Blind or Have Low Vision Aged 5 Years and Younger

Walking alone (without assistance) is considered by the World Health Organization as the terminal independent walking milestone, typically achieved by 18 months. Children born with severe visual impairment and blindness (visual impairments) do not achieve independent walking milestones on time. This study examined independent walking in 35 children with visual impairments (VIs) aged 14–69 months. Before treatment, they had limited to no anticipatory control. Wearing the pediatric belt cane (PBC) provided them with consistent, tactile anticipatory control. Thirty-five participants with VIs’ independent walking milestones were analyzed using pre- and post-video recordings provided weekly 1 month before and the 3 months after obtaining the PBC. The PBC consisted of a rectangular frame that connects to a custom-made belt with magnets. The PBC provided no weight support. While none of the participants had motor impairments, 80% of them were receiving physical therapy services prior to obtaining a PBC. Fifty-four percent were receiving orientation and mobility services, and half were equipped with hand-held mobility tools (long canes, adaptive mobility devices, push toys, and reverse walkers). A paired samples t-test indicated a significant difference between the before and with PBC scores ( N = 35, t = −13.0, df = 34, p = .000). Participants demonstrated significantly improved independent walking after wearing their PBC regularly over 3 months. Before PBC, the participants demonstrated delayed independent walking milestones. Most participants walked only with assistance. Those who walked independently experienced unavoidable bodily collisions and used a slow pace with poor gait patterns. After being provided PBCs, these same participants’ independent walking milestones improved, all but three were walking independently and five were observed independently running. Wearing their PBCs allowed them to perform motor skills, like running, often described as needing to be specifically taught to learners with VIs due to their inability to learn incidentally through visual observation.

The role of the anterior temporal cortex in action: evidence from fMRI multivariate searchlight analysis during real object grasping

Intelligent manipulation of handheld tools marks a major discontinuity between humans and our closest ancestors. Here we identified neural representations about how tools are typically manipulated within left anterior temporal cortex, by shifting a searchlight classifier through whole-brain real action fMRI data when participants grasped 3D-printed tools in ways considered typical for use (i.e., by their handle). These neural representations were automatically evocated as task performance did not require semantic processing. In fact, findings from a behavioural motion-capture experiment confirmed that actions with tools (relative to non-tool) incurred additional processing costs, as would be suspected if semantic areas are being automatically engaged. These results substantiate theories of semantic cognition that claim the anterior temporal cortex combines sensorimotor and semantic content for advanced behaviours like tool manipulation.

A Dermoscopic Evaluation of Melasma Treated with Tranexamic Acid

Background:&#x0D; Melasma is a great challenge to the dermatologist. Choosing the proper treatment and the evaluation method are hard issues. Tranexamic acid [TA] injections showed promising results. The dermoscope is a non -invasive hand held tool&#x0D; Objective:&#x0D; To evaluate the efficacy of TA injections in the management of melasma and to assess a new dermoscopic score for assessment of melasma severity.&#x0D; Patients &amp; Methods:&#x0D; Twenty-seven patients were enrolled in the study. They were assessed clinically, and by dermoscopy. An intradermal tranexamic acid was injected on the melasma. Melasma Area and Severity Index [MASI] was used to assess the melasma.&#x0D; Results: high significant difference was found between pre [4.700±2.1213] and post [2.811±2.0870] treatment values of MASI score [p= 0.0001]. Clinically TA treatment showed a dramatic improvement in MASI.&#x0D; Conclusion:&#x0D; The intradermal usage of TA can actually decrease improved the melasma. This was confirmed by the MASI scores and the dermoscope. The dermoscope could be considered as a useful objective score for melasma.

Using Facial Landmark Detection on Thermal Images as a Novel Prognostic Tool for Emergency Departments.

IntroductionEmergency departments (ED) at hospitals sometimes experience unexpected deterioration in patients that were assessed to be in a stable condition upon arrival. Odense University Hospital (OUH) has conducted a retrospective study to investigate the possibilities of prognostic tools that can detect these unexpected deterioration cases at an earlier stage. The study suggests that the temperature difference (gradient) between the core and the peripheral body parts can be used to detect these cases. The temperature between the patient's inner canthus (core temperature) and the tip of the nose (peripheral temperature) can be measured with a thermal camera. Based on the temperature measurement from a thermal image, a gradient value can be calculated, which can be used as an early indicator of potential deterioration.ProblemThe lack of a tool to automatically calculate the gradient has prevented the ED at OUH in conducting a comprehensive prospective study on early indicators of patients at risk of deterioration. The current manual way of doing facial landmark detection on thermal images is too time consuming and not feasible as part of the daily workflow at the ED, where nurses have to triage patients within a few minutes.ObjectiveThe objective of this study was to automate the process of calculating the gradient by developing a handheld prognostic tool that can be used by nurses for automatically performing facial landmark detection on thermal images of patients as they arrive at the ED.MethodsA systematic literature review has been conducted to investigate previous studies that have been done for applying computer vision methods on thermal images. Several meetings, interviews and field studies have been conducted with the ED at OUH in order to understand their workflow, formulate and prioritize requirements and co-design the prognostic tool.ResultsThe study resulted in a novel Android app that can capture a thermal image of a patient's face with a thermal camera attached to a smartphone. Within a few seconds, the app then automatically calculates the gradient to be used in the triage process. The developed tool is the first of its kind using facial landmark detection on thermal images for calculating a gradient that can serve as a novel prognostic indicator for ED patients.

Experimental Study on the Response of Hand-Transmitted Vibration from an EVA Power Tool

The objective of this paper is to accurately measure the vibration response of tools and hands by simulating the hand-held power tools, which are operated by astronauts wearing extravehicular spacesuit gloves under microgravity conditions. The total vibration value and the daily vibration exposure of the subject’s hand are obtained. The results show that the opisthenar is more sensitive to the vibration frequency less than 200 Hz. After frequency weighting, the vibration exposure in the composite state of wearing an unpressurized spacesuit glove on the opisthenar is 23.6% greater than the vibration exposure of the palm, and for the bare hand, the percentage is 25.1% under the same condition. Because the operation time of tightening a screw is longer than that of loosening, the tightening operation performed by wearing spacesuit gloves produces 15.7% more mean vibration exposure on the palm and opisthenar than the loosening operation. The results of vibration transmissibility characterized by the total vibration weighted method and the total vibration unweighted method are 0.039 and 0.094, respectively. In comparison with bare hands, the mean daily vibration exposure on the palm and opisthenar in the composite state by wearing spacesuit gloves is 16.3% less, indicating that the unpressurized spacesuit gloves have an effect on vibration reduction. The research reveals the law of hand-transmitted vibration caused by the coupling of the extravehicular activities (EVA) power tools and spacesuit gloves, and provides a novel method for further similar tests and verification of hand-held EVA power tools.