Manual Force Research Articles

KINEMATIC ANALYSIS OF OPENING AND CLOSING ROOF MECHANISM FOR LOADING FREIGHT WAGON

Input kinematic parameters during the movement of the mechanism for opening and closing the roof of Tagnpps 95 m3 wagon were analyzed. This included studying all components including the steering wheel, motion transmissions, and the roof of the wagon. The process of creating a 3D model of the mechanism for opening and closing the wagon roof in SolidWorks software is described, as well as the procedure of kinematic analysis of the mechanism in SolidWorks Motion. The manual force required to operate the mechanism for opening and closing the roof is calculated. To optimize the existing mechanism, the case of replacing the current reducer gear with a reducer of a smaller gear ratio is taken into consideration.

Design, integration, and field evaluation of a robotic blossom thinning system for tree fruit crops

AbstractThe United States (US) apple industry relies heavily on semi‐skilled manual labor force for essential field operations such as training, pruning, blossom and green fruitlet thinning, and harvesting. Blossom thinning is one of the crucial crop‐load management practices to achieve desired crop load, fruit quality, and return bloom. While several techniques such as chemical and mechanical thinning are available for large‐scale blossom thinning, such approaches often yield unpredictable thinning results and may damage the canopy, spurs, and leaf tissue. Hence, growers still depend on laborious, labor‐intensive, and expensive manual hand blossom thinning for desired thinning outcomes. This research presents a robotic solution for precision blossom thinning in apple orchards using a deep learning‐based computer vision system, a six‐degrees‐of‐freedom UR5e robotic manipulator, and an electrically actuated miniature end‐effector. The integrated robotic system was evaluated in a commercial apple orchard which showed promising results for targeted and selective blossom thinning. Two thinning approaches, center and boundary thinning, were investigated to evaluate the system's ability to remove varying proportions of flowers from apple flower clusters. During boundary thinning, the end‐effector was actuated around the cluster boundary, while center thinning involved end‐effector actuation only at the cluster centroid for a fixed duration of 2 s. Field evaluation results showed that the boundary thinning approach thinned 67.2% of flowers from the targeted clusters with a cycle time of 9.0 s per cluster, whereas the center thinning approach thinned 59.4% of flowers with a cycle time of 7.2 s per cluster. Upon further improvement for commercial adoption, the proposed system could help address problems faced by apple growers with current hand, chemical, and mechanical blossom thinning approaches.

Real-world study of the leakage of two types of infusion bags in multicenter pharmacy intravenous admixture service (PIVAS).

Background: This study sought to analyze the leakage rate, economic loss caused by leakage, leakage reasons, and usage of upright polypropylene infusion bags and non-polyvinyl chloride (PVC) infusion bags, two types of closed intravenous infusion containers used in pharmacy intravenous admixture service (PIVAS), to improve the product quality of drug infusion packaging materials, reduce drug and clinical economic losses, and reduce the safety hazards of medication. Method: A real-world study was used to collect statistics for these infusion containers. The study was conducted in 21 hospitals in China from September to December 2022. Upright polypropylene infusion bags or non-PVC infusion bags in PIVAS of these 21 hospitals were chosen as the research material. Results: In total, 2,349,899 upright polypropylene infusion bags and 3,301,722 non-PVC infusion bags were collected. Eleven cases of upright polypropylene infusion bag leakage occurred (with a the leakage rate of 0.05‱), and 394 cases of non-PVC infusion bag leakage occurred (with a leakage rate of 1.19‱). The leakage rate of non-PVC infusion bags was significantly higher than that of upright polypropylene infusion bags (p < 0.01). The main reason for leakage in upright polypropylene infusion bags was sharp objects such as glass fragments or aluminum caps piercing the bag. The main reason for leakage in non-PVC infusion bags was squeezing, stacking, and uneven arrangement that causes folding of edges. For non-PVC bags, additional reasons for leakage included leakage at the nozzle joint, excessive manual or machine throwing force, and excessive dosage. The economic loss of upright polypropylene infusion bags was 1,116.56 CNY. The economic loss of non-PVC infusion bags was 32,210.86 CNY. Conclusion: Based on real-world study data on the leakage of upright polypropylene infusion bags and non-PVC infusion bags in multicenter PIVAS, it can be concluded that the leakage rates of upright polypropylene infusion bags are significantly lower than those of non-PVC infusion bags in PIVAS, and the economic losses due to upright polypropylene infusion bags are lower than those due to non-PVC infusion bags in PIVAS. Therefore, we can infer that upright polypropylene infusion bags are superior to non-PVC infusion bags.

Safe Manipulation in Robotic Surgery Using Compliant Constant-Force Mechanism

Safe manipulation of soft tissue in robotic-assisted minimally invasive surgery (RMIS) is a challenging task for surgeons. The conventional solution is to introduce tactile sensors to measure the tool-tissue interaction force, and then transmit the signal back to the surgeon to enable manual force control. However, since the RMIS-forceps is very small, even the hand tremor of the surgeon could lead to unstable force applied to the tissue. To cope with this problem, we present a compliant constant-force mechanism (CFM) in this article to achieve stable force regulation of RMIS forceps. The proposed CFM is comprised of a pair of symmetrical compliant slider-crank mechanisms, whose mechanical behavior can be described by a pseudo-rigid-body (PRB) model. Cross-spring-based compliant joints are also introduced to improve the model accuracy, while the magnitude of the generated constant force can be adjusted by using detachable slider-crank mechanisms with different force configurations. In this work, the proposed CFM is selective-laser-sintered with polyamide (PA2200) and is actuated by a linear motor. Experiments were also conducted and successfully validated the constant-force performance of the proposed CFM. Furthermore, a grasping test of artificial artery was also performed, which demonstrated the application of the developed CFM system in RMIS.

Aging reduces manual dexterity and force production asymmetries between the hands

ABSTRACT Age-related effects on motor asymmetry provide insight into changes in cortical activation during aging. To investigate potential changes in manual performance associated with aging, we conducted the Jamar hand function test and the Purdue Pegboard test on young and older adults. All tests indicated reduced motor asymmetry in the older group. Further analysis suggested that a significant decline in dominant (right) hand function resulted in less asymmetric performance in older adults. The finding is inconsistent with the application of the HAROLD model in the motor domain, which assumes improved performance in the non-dominant hand, leading to a reduction of motor asymmetry in older adults. Based on the manual performance in young and older adults, it is suggested that aging reduces manual asymmetry in both force production and manual dexterity due to the reduced performance of the dominant hand.

Effectiveness of a theory-based educational intervention on work-related musculoskeletal disorders preventive behaviors among assembly-line female workers: a study protocol for a randomized controlled trial

BackgroundThe use of preventive behaviors of musculoskeletal disorders (MSDs) requires proper training, which leads to correct decisions regarding maintaining postures at work and performing stretching exercises. Due to very repetitive work, applying manual force, improper postures, and static contractions of proximal muscles, assembly-line female workers suffer from musculoskeletal pains. It is assumed that structured and theory-based educational intervention using a learning-by-doing (LBD) approach may increase the preventive behaviors against MSDs and reduce the consequences of these disorders.MethodsThis randomized controlled trial (RCT) will be conducted in three phases: phase 1: validation of the compiled questionnaire, phase 2: determining the social cognitive theory (SCT) constructs that predict the preventive behaviors of MSDs in assembly-line female workers, and phase 3: designing and implementing the educational theory. The educational intervention is based on the LBD approach, and the study population includes assembly-line female workers in electronic industries of Iran, who are randomly divided into two intervention and control groups. The intervention group received the educational intervention in the workplace and the control group does not receive any intervention. The theory-based educational intervention includes evidence-based information along with pictures, fact sheets, and published literature about a good posture at work and the need to perform proper stretching exercises. The educational intervention aims to improve the knowledge, skills, self-efficacy, and intention of assembly-line female workers to adopt preventive behaviors of MSDs.DiscussionThe present study will evaluate the effects of maintaining a good posture at work and performing stretching exercises on the adherence to preventive behaviors of MSDs among assembly-line female workers. The developed intervention is easily implemented and evaluated in a short period of time based on the improved score of the rapid upper limb assessment (RULA) method and the mean score of adherence to stretching exercises and can be provided by a health, safety, and environment (HSE) expert.Trial registrationClinicalTrials.gov IRCT20220825055792N1. Registered on 23 September 2022 with the IRCTID.

Direct 4D printing of gradient structure of ceramics

Shape-morphing ceramics with complex geometries can be applied in several scenarios; however, the fabrication of such structures remains challenging owing to the brittleness and stiffness of ceramics. This paper proposes a direct four-dimensional (4D) printing technology for achieving and precisely controlling complex ceramic architectures that may be transformed, in a free-standing manner, from a pre-programmed gradient structure after sintering without intervention of a manual physical force and stimuli. The proposed method involves three steps: printing, curing, and sintering. The designability and flexibility of the proposed approach were demonstrated by preparing different topologies, such as fingers in a palm (multi-curvature), leaves (anisotropic morphing), a dragonfly (high-precision localised deformation), and an intricate structure (self-locking). The obtained ceramics exhibited excellent mechanical properties. This study can help establish a novel paradigm for designing ceramics with complex structures, with potential for application in various fields such as aerospace and biomedical engineering.

Clinical and Social Features of Patients with Eye Injuries Admitted to a Tertiary Hospital: A Five-Year Retrospective Study from Crete, Greece

Eye injuries are a major cause of visual disability worldwide and may present a burden to both quality of life of the sufferers and healthcare services. The aim of this study was to extract and triangulate information on the demographic, clinical, and social features of eye-injured adult patients admitted to a tertiary hospital in Greece. The design was a five-year retrospective study of eye-injured adult patients, admitted to the General University Hospital of Heraklion, Crete (GUHH), the single tertiary referral hospital on the island. Drawing the profile of eye-injured patients may add to future health planning. Data collected from 1 January 2015 to 31 December 2019, such as sociodemographic features and clinical information, were extracted. One hundred twenty-eight patients were included. Of those, there was no available information on activity during injury for 6 patients, 78 (60.9%) had work-related ocular injuries, and 44 (34.4%) had non-work-related ocular injuries. Patients with no current formal employment, those who were retired, and formally unemployed and manual force workers had the higher rates of work-related injuries. The most common work-related injuries were closed globe injuries, specifically contusions, while ruptures and penetrating wounds were the most frequent of the open globe injuries. Within the univariate analyses, work-related eye injuries were significantly associated with male gender, middle age, and the place related to daily work activity. Determinants of poor final visual acuity (VA) were the initial VA, the type of injury (p < 0.0001), the distance of the place of residence from the hospital, and the time to hospital admission (p < 0.013). In a multivariate analysis, referred patients and those with open globe injuries arrived at hospital after a two-hour interval compared with those who were not referred and those with closed globe injuries (p ≤ 0.05). A reduction in the time to hospital admission deserves further attention. The interconnection of community and health system services through a capacity increase and networking needs further research in order to obtain targeted and viable access for eye-injured patients.

Application of an Intraoperative Limb Positioner for Adjustable Traction in Both-Column Fractures of the Acetabulum: A Technical Note with Clinical Outcome

Traction of the ipsilateral leg is usually required to facilitate fracture reduction while operating both-column acetabular fractures. However, it is challenging to maintain constant traction manually during the operation. Herein, we surgically treated such injuries while maintaining traction using an intraoperative limb positioner and investigated the outcomes. This study included 19 patients with both-column acetabular fractures. Surgery was performed after the patient's condition had stabilized, at an average of 10.4 days after injury. The Steinmann pin was transfixed to the distal femur and connected to a traction stirrup; subsequently, the construct was affixed to the limb positioner. A manual traction force was applied through the stirrup and maintained with the limb positioner. Using a modified Stoppa approach combined with the lateral window of the ilioinguinal approach, the fracture was reduced, and plates were applied. Primary union was achieved in all cases at an average of 17.3 weeks. The quality of reduction at the final follow-up was found to be excellent, good, and poor in 10, 8, and 1 patients, respectively. The average Merle d'Aubigné score at the final follow-up was 16.6. Surgical treatment of both-column acetabular fracture using intraoperative traction with a limb positioner yields satisfactory radiological and clinical outcomes.

Vitreosity as a Major Grain Quality Indicator—Upgrading the Grain-Cutter Method with a New Blade

One of the main quality characteristics of cereals, especially wheat is its hardness which is closely related with grain’s vitreosity, one of the main quality indicators of a variety. Determination of vitreosity is usually done visually: namely, after the grain is cut with a commercially available grain-cutters, the cut can result in broken or crushed grains which disables the reading and hinders the precision and accuracy. Also, the moment produced from the manual force on the grain-cutter crank, needed to cut the sample of cca. 50 grains placed in the cutter is an average of 30 Nm. Due to the resistance of the grain, yank force appears. This force can cause the whole instrument to be displaced during cutting. To minimize the errors using a commercially available cutter, a new knife/blade has been implemented and tested. The blade of the new knife is turned at the inclination angle of 49° in relation to the cutting objects (grains). This design solution enables achievement of the grain “cutting”, not grain “tearing”, as observed with the existing commercial design solution. With the proposed new design solution, amount of the moment is reduced to 2.72 Nm and the yank force is completely avoided. Also, a significantly lower amount of the cutting force, on the knife blade is achieved. The results obtained with the new knife gave a better read, were more precise, and the gadget was easier to operate since it demanded lower force to cut the grains. The novelty introduced by this research provided better and more reliable insight into determining the vitreousness of grains. Providing a clearer cut and better readability, this solution goes beyond the current literature by reducing the force required for analysis and speeding up the analysis process.

Preclinical dental students self-assessment of an improved operative dentistry virtual reality simulator with haptic feedback

To test and evaluate the second installment of DENTIFY, a virtual reality haptic simulator for Operative Dentistry (OD), on preclinical dental students, by focusing on user performance and self-assessment. Twenty voluntary unpaid preclinical dental students, with different background experience, were enrolled for this study. After the completion of an informed consent, a demographic questionnaire, and being introduced to the prototype (on the first testing session), three testing sessions followed (S1, S2, S3). Each session involved the following steps: (I) free experimentation; (II) task execution; S3 also included (III) completion of questionnaires associated with the experiment (total of 8 Self-Assessment Questions (SAQ)); and (IV) guided interview. As expected, drill time decreased steadily for all tasks when increasing prototype use, verified by RM ANOVA. Regarding performance metrics (Comparisons by Student’s t-test and ANOVA) recorded at S3, in overall, a higher performance was verified for participants with the following characteristics: female, non-gamer, no previous VR experience and with over 2 semesters of previous experience of working on phantom models. The correlation between the participants’ performance (drill time), for the four tasks, and user self-assessment evaluation, verified by Spearman’s rho analysis, allowed to conclude that a higher performance was observed in students who responded that DENTIFY improved their self perception of manual force applied. Regarding the questionnaires, Spearman’s rho analysis showed a positive correlation between the improvement DENTIFY inputs on conventional teaching sensed by students, also enhancing their interest in learning OD, their desire to have more simulator hours and the improvement sensed on manual dexterity. All participating students adhered well to the DENTIFY experimentation. DENTIFY allows for student self-assessment and contributes to improving student performance. Simulators with VR and haptic pens for teaching in OD should be designed as a consistent and gradual teaching strategy, allowing multiplicity of simulated scenarios, bimanual manipulation, and the possibility of real-time feedback to allow for the student’s immediate self-assessment. Additionally, they should create performance reports per student to ensure self-perception/criticism of their evolution over longer periods of learning time.

The role of new staplers in reducing the incidence of air leak.

Surgical staplers play an important role in the contemporary minimally invasive thoracic surgery including resection of lung tissue. However, staple line failure resulting in postoperative air leaks is a common complication after lung surgery, that if persist more than five days are defined as prolonged air leaks (PALs). PALs are associated with increased length of stay, patient morbidity and mortality, and hospital costs. To reduce the incidence of PALs, stapler devices underwent in the last years ongoing development aimed at improving device-to-tissue interaction. This clinical practice review explores the most important aspects of the evolution of surgical staplers, based on the review of the available literature. Modern staple cartridges entail small bumps to engage tissue and minimize tissue movement during compression and firing. Staplers with graduated staple heights are advocated to generate less stress on tissue during compression and clamping, thus affording greater perfusion into the staple line. However, air leaks may occur from an appropriate staple line with complete pleural coverage and perfusion due to enlarged staple canals after lung inflation, particularly in case of emphysema. To buttress staple line, thus prevent air leaks in high-risk patients, several types of tissue coverage (bovine pericardium, polytetrafluoroethylene, knitted calcium alginate, bioabsorbable polyglycolic acid) have been successfully developed in the last years. Finally, the most advanced stapler technology is represented by the new energy powered staplers, able to eliminate the manual firing force, monitor tissue compression during firing, and making automatic adjustments to optimize the staple line.

Customers Satisfaction on Robots, Artificial Intelligence and Service Automation (RAISA) in the Hotel Industry: A Comprehensive Review

Due to the 4th Industrial Revolution, Artificial Intelligence and other internet technologies such as RAISA (Robots, Artificial Intelligence and Service Automation) have been adopted in various industries, including the hospitality and tourism industry. As the industry traditionally offers services through manual labor force, more companies adopt RAISA through a commercial service in the form of chatbots, delivery robots, robot concierge, conveyor restaurants, self-service information/check-in/check-out kiosks, and many others. The current academic resources mainly focus on customer perception or evaluation of robots themselves, and few studies link robot services with customers’ overall experience of hospitality services. This study aims to evaluate the current status of RAISA studies in the hotel industry and propose directions for future research. Thirty-seven articles were identified from Google Scholar. These articles were reviewed from four perspectives, namely, journal/year distribution, methodology, research context, theoretical foundation. Findings reveal that most studies on RAISA in the hotel industry focus on RAISA’s impacts on the hotel industry, RAISA service quality, customer acceptance of RAISA service, customer satisfaction and factors influencing Customers’ Satisfaction on RAISA Service and quantitative approach is the dominant research method. To this end, five research directions cover outstanding themes as follows: 1) strategic assessment of RAISA performance, 2) hotel financial impacts on RAISA employment, 3) customers’ satisfaction and RAISA service quality, 4) macro environment impacts on RAISA in hotels, and 5) premium determinants on customers’ acceptance on RAISA.

Determination of the Predictors with the Greatest Influence on Walking in the Elderly.

Background and Objectives: Previous studies have revealed that independent variables (lower extremity strength, postural control ability, and body composition) influence gait performance and variability, but the difference in the relative influence between these variables is unclear. Hence, this study determines the variable that is the most influential predictor of gait performance and variability among potential independent variables in the elderly. Materials and Methods: Seventy-eight subjects aged ≥60 years participated. For each subject, the gait variables and lower extremity muscle strength were measured using an accelerometer worn on both feet during a 6-minute walk and a manual force sensor, respectively. The static balance ability was measured through two force plates, and the body composition was measured by applying bioelectrical impedance analysis. Linear regression analyses were performed stepwise to determine whether these variables affect gait performance and variability. Results: After adjusting for sex and gait performance, the ankle strength, body fat mass, mean velocity in the medial-lateral direction, ankle plantar flexion strength, and girth were predictors of gait speed dorsiflexion, gait performance, swing width of the gait performance, walking speed, and gait variability, respectively. Conclusions: Overall, gait performance in the elderly is related to muscle strength, postural control, and body composition in a complex manner, but gait variability appears to be more closely related to ankle muscle strength. This study provides further evidence that muscle strength is important in motor function and stability.

Stability of virtual reality haptic feedback incorporating fuzzy-passivity control

This study investigated the stability of virtual reality (VR) haptic feedback from the perspective of energy. A fuzzy controller was designed on the basis of passivity theory to mitigate the shock and divergence in a virtual component caused by the negative damping coefficient and the high spring coefficient. Compared with a standard passivity controller, a fuzzy-passivity controller is more effective in shortening the time required to stabilize a system with high initial energy and devices that consume energy slowly. First, MATLAB/Simulink was employed for stability simulation and analysis. The fuzzy-passivity controller provided more favorable stability convergence than did the standard passivity controller. The simulation results align with expectations. Second, the completed VR system was applied as an experiment platform for verifying the feasibility of the fuzzy-passivity controller. To achieve one degree of freedom in the experiments, a robotic arm was exclusively designed to replace manual force. Finally, compared with standard passivity control systems, the results indicated that the fuzzy-passivity controller enables improved control over the stability of VR haptic feedback.

Design and Mathematical Modeling of a Pneumatic Artificial Muscle-Actuated System for Industrial Manipulators

Pneumatic muscles have significant advantages over typical pneumatic cylinders, such as smooth speed adjustment, higher power-to-weight ratio and longer operating life. Applying a pneumatic artificial muscle is a way to considerably simplify manipulator mechanisms due to its physical properties. This paper deals with the development of positioning control principles of pneumatic artificial muscle drive and presents numerical and experimental investigations of different operation modes such as lifting and lowering a load under normal working conditions, operation in a case of a sudden load separation and position control by manual operator force. In this work, the mathematical model elaborated earlier was numerically and experimentally investigated. Experimental validation of static and dynamic characteristics confirmed the results of the theoretical studies, so the elaborated model can be used to design a PAM-based manipulator with required characteristics.

Portable Ultrasound Equals Arthroscopy for Assessment of Syndesmotic Instability

Category: Ankle; Arthroscopy Introduction/Purpose: Syndesmotic instability, when subtle, can be challenging to diagnose-and often requires visualization of the syndesmosis during applied stress. Portable ultrasonography is increasingly used to evaluate ankle instability at the point of care. This study aims to evaluate 1) whether portable ultrasonography (P-US) can diagnose syndesmotic instability in the sagittal plane, and 2) how P-US measurements compare to arthroscopic evaluation. Methods: Eight fresh, above-knee cadaveric specimen were used. The syndesmosis was evaluated with P-US and arthroscopy in the intact state, and thereafter with progressive sectioning of, 1) anterior-inferior tibiofibular ligament (AITFL), 2) interosseous ligament (IOL), and 3) posterior-inferior tibiofibular ligament (PITFL). Sagittal plane translation was simulated with 100N of anterior to posterior (A to P) and posterior to anterior (P to A) directed force using a bone hook. Separately, a 50N manual force was applied to the fibular tip and measured with P-US to simulate a fibular 'shuck test' performed in the clinical setting. Results: When all three syndesmotic ligaments were transected, there was a significant increase in fibular motion in the sagittal plane when evaluated using portable ultrasonography with application of 50N of manual pressure and when applying a 100N hook test when measuring total sagittal plane motion (p=&lt;0.001 and p=0.009). Arthroscopy demonstrated significant increased motion with a 100N hook test when measuring total sagittal plane motion (p&lt;0.001). Conclusion: P-US performed similarly to arthroscopy when diagnosing syndesmotic instability in the sagittal plane. P-US also offers several advantages over arthroscopy, including availability, non-invasiveness, low cost, and affording contralateral comparison. The promise of this technique suggests it should be further explored as a potential future standard for the diagnostic assessment of occult syndesmotic instability in the sagittal plane.

Current Practice Behaviors and Perceptions of Physiotherapist with Respect to Management of Individual with Osteoporosis

Objective: To determine the behaviors and perceptions of physiotherapist with respect to management of individual with osteoporosis. Study Design and Sampling Techniques: This was a cross sectional study with convenient sampling Study Settings &amp; Participants: This study was conducted among physiotherapists working in University Institute of Physical therapy Clinics, Lahore, and Faisal hospital clinics, Faisalabad and Imran Idrees Institute of Rehabilitation Sciences, Sialkot. Data Collection Tools: A self-structured questionnaire focused on three aspects was used. First section was on physiotherapist concern for different types of treatment modes in osteoporotic patients, second section was on physiotherapist concern for manual therapy and third section was on physiotherapist concern about tissue injuries in response to manual therapy. Data Analysis: The data was analyzed using SPSS version 21. Results: The current study comprised of 100 physiotherapists 57(57 %) were female and 43(43 %) were male and 3% of respondents chosen the treatment modes such as ‘other’ as compared to others treatment modes. 75%of physiotherapists were using the strengthening exercises for treatment in osteoporotic patients. Forty one percent of physiotherapists were using the manual therapy 58% physiotherapists had showed up the concern with the use of manual therapy techniques as management for osteoporosis .This was more than half of the sample size taken for the study. Fifty one percent of physiotherapists had more concerned about muscle injuries and 71% were concerned about others injuries and fracture such as wrist fracture and hip fracture by using manual therapy. Conclusion: Use of slight progressive strengthening and exercise is better to overcome osteoporotic bone fractures due to manual force application during strength training in subjects with Osteoporosis Keywords: Behavior, Perception, Physiotherapist, Osteoporosis

Tines made of degradable materials with decreasing removal forces: An option to facilitate passive-fixation leads extraction from the very beginning?

Risks during transvenous lead extraction (TLE) are serious, especially for passive fixation (PFix) leads. We attempted to fabricate a PFix lead using degradable tines to facilitate lead removal. Dried polymer mixture with poly (d-lac tide-co-glycolicde acid) (PLGA)/Poly (l-lac tide-co-ε-caprolactone) (PLCL) were put into to a specially-made mold respectively to test the tine-making feasibility and the final formulation was determined as PLGA25-PLCL75 with mass ratio 25:75 of PLGA/PLCL. Dynamic mechanical analysis and X-ray Diffraction showed excellent physicochemical characterizations, and further tests demonstrated satisfying mechanical properties similar to traditional silicone tines. The PLGA25-PLCL75 also showed low cytotoxicity and appropriate biodegradability in vitro and in vivo. The PFix leads were tested to reassure the implantation feasibility before implantation via standard surgery operation procedure. Then the leads were implanted into dog’s endocardium. The animal study showed the degradable tines could accomplish fixation stability and were with less manual extraction forces comparing with traditional silicon fixation tines in 7-month’s observation time. Tines made of PLGA25-PLCL75 blends were almost degraded totally only few remnants observed under microscope comparing with intact silicon materials at the tine-myocardial interfaces. The PFix lead might revolutionize products because of the introduction of this degradable fixation tines that make easier removal.

The Design &amp; Implementation of a Self-adaptive Hybrid Electric Skateboard

This paper proposes a novel electric skateboard control architecture to hybridize the skater's manual operation and electric motor drive. The proposed scheme does not need a handheld remote controller for steering; hence provides better man-machine coordination and enhances the safety of new skaters. For this purpose, a torque-speed control algorithm is designed to compensate for the manual acceleration force and rolling resistance by sensing the motor's speed, acceleration, and torque outputs. The compensation level is configurable according to the skater's comfortableness. The proposed electric control solution also enhances the battery mileage per charging and can be applied to various electric skateboards since it does not require a dedicated weight/pressure sensor to detect if the skater is on or off the board. The control scheme is simulated in MATLAB/Simulink and experimentally verified by a controller based on C2000 DSP that supports sensorless brushless DC(BLDC) motor drive.