This study was aimed to determine the mechanical strength of composites made from Agave cantala with an unsaturated polyester matrix and microcrystalline cellulose.Cantala fiber(CF)was treated with 6%Na OH with immers...This study was aimed to determine the mechanical strength of composites made from Agave cantala with an unsaturated polyester matrix and microcrystalline cellulose.Cantala fiber(CF)was treated with 6%Na OH with immersion times of 0 h(UF),3 h(AK3),6 h(AK6),9 h(AK9),and12 h(AK12).Thermogravimetric analysis(TGA)analysis shows that treated CF has higher thermal stability than CF without treatment.Cantala fiber was tested by X-ray diffraction.After alkali treatment with a 6-h soaking,it had a crystallinity index of 73.65%.Scanning electron microscopy(SEM)showed that the fibers were cleaner after alkali treatment because hemicellulose,wax,and other impurities were removed.Examination of the contact angle and surface energy showed that treated CF has smaller contact angles and greater surface energy.展开更多
The dynamic effects of inertial loads on the interface stresses between a residual limb and the trans-tibial prosthetic socket were investigated. A 3-D nonlinear finite element model, based on the actual geometry of t...The dynamic effects of inertial loads on the interface stresses between a residual limb and the trans-tibial prosthetic socket were investigated. A 3-D nonlinear finite element model, based on the actual geometry of the residual limb, including internal bones and socket liner, was developed to study the mechanical interaction between the socket and the residual limb during walking. To simulate the friction/slip boundary conditions between the skin and liner, automated surface-to-surface contact was used. The results show that interface pressure and shear stress have a similar double-peaked waveform shape in the stance phase. The average difference in interface stresses between the cases with and without consideration of inertial forces is 8.4% in the stance phase and 20.1% in the swing phase. The results suggest that the dynamic effects of inertial loads on interface stress distribution during walking must be considered in prosthetic socket design.展开更多
To help comfort for an amputee, it is important to understand the load distribution between the residual limb and the prosthetic socket for a prosthetic socket system. An interfacial stress sensor was presented which ...To help comfort for an amputee, it is important to understand the load distribution between the residual limb and the prosthetic socket for a prosthetic socket system. An interfacial stress sensor was presented which was capable of measuring compressive pressure and shear stress simultaneously. A mathematical model was built and an experiment was conducted to obtain the transfer function of interfacial stress sensor to compressive pressure. The results show that the sensor is capable of measuring a range of 30-217 kPa compressive pressure with a relative error of 32.15% in lower range and 6.22% in upper range.展开更多
In recent years,the functionality of myoelectric prosthetic hands has improved as motors have become smaller and controls have become more advanced.Attempts have been made to reproduce the rotation and flexion of the ...In recent years,the functionality of myoelectric prosthetic hands has improved as motors have become smaller and controls have become more advanced.Attempts have been made to reproduce the rotation and flexion of the wrist by adding degrees of freedom to the wrist joint.However,it is still difficult to fully reproduce the functionality of the wrist joint owing to the weight of the prosthesis and size limitations.In this study,we developed a new socket and prosthetic hand control system that does not interfere with the wrist joint motion.This allows individuals with hand defects who previously used prosthetic hands with fixed wrist joints to freely use their remaining wrist functionality.In the pick-and-place experiment,where blocks were moved from higher to lower locations,we confirmed that the proposed system resulted in a lower elbow position compared with the traditional prosthesis,and the number of blocks transported increased.This significantly reduced the compensatory motion of the elbow and improved the user’s performance compared with the use of a conventional prosthetic hand.This study demonstrates the usefulness of a new myoelectric prosthetic hand that utilizes the residual functions of people with hand deficiencies,which have not been utilized in the past,and the direction of its development.展开更多
文摘This study was aimed to determine the mechanical strength of composites made from Agave cantala with an unsaturated polyester matrix and microcrystalline cellulose.Cantala fiber(CF)was treated with 6%Na OH with immersion times of 0 h(UF),3 h(AK3),6 h(AK6),9 h(AK9),and12 h(AK12).Thermogravimetric analysis(TGA)analysis shows that treated CF has higher thermal stability than CF without treatment.Cantala fiber was tested by X-ray diffraction.After alkali treatment with a 6-h soaking,it had a crystallinity index of 73.65%.Scanning electron microscopy(SEM)showed that the fibers were cleaner after alkali treatment because hemicellulose,wax,and other impurities were removed.Examination of the contact angle and surface energy showed that treated CF has smaller contact angles and greater surface energy.
文摘The dynamic effects of inertial loads on the interface stresses between a residual limb and the trans-tibial prosthetic socket were investigated. A 3-D nonlinear finite element model, based on the actual geometry of the residual limb, including internal bones and socket liner, was developed to study the mechanical interaction between the socket and the residual limb during walking. To simulate the friction/slip boundary conditions between the skin and liner, automated surface-to-surface contact was used. The results show that interface pressure and shear stress have a similar double-peaked waveform shape in the stance phase. The average difference in interface stresses between the cases with and without consideration of inertial forces is 8.4% in the stance phase and 20.1% in the swing phase. The results suggest that the dynamic effects of inertial loads on interface stress distribution during walking must be considered in prosthetic socket design.
基金National Natural Science Foundations of China(No.60976058,No.61274078)Innovation Program of Shanghai Municipal Education Commission,China(No.13ZZ049)Fundamental Research Funds for the Central Universities of Xidian University,China(No.K5051304005)
文摘To help comfort for an amputee, it is important to understand the load distribution between the residual limb and the prosthetic socket for a prosthetic socket system. An interfacial stress sensor was presented which was capable of measuring compressive pressure and shear stress simultaneously. A mathematical model was built and an experiment was conducted to obtain the transfer function of interfacial stress sensor to compressive pressure. The results show that the sensor is capable of measuring a range of 30-217 kPa compressive pressure with a relative error of 32.15% in lower range and 6.22% in upper range.
基金supported by JSPS KAKENHI(grant numbers JP18H03761,JP21K14125,and JP23H00166)the New Energy and Industrial Technology Development Organization(NEDO)the Ministry of Health,Labor and Welfare(MHLW)in Japan.
文摘In recent years,the functionality of myoelectric prosthetic hands has improved as motors have become smaller and controls have become more advanced.Attempts have been made to reproduce the rotation and flexion of the wrist by adding degrees of freedom to the wrist joint.However,it is still difficult to fully reproduce the functionality of the wrist joint owing to the weight of the prosthesis and size limitations.In this study,we developed a new socket and prosthetic hand control system that does not interfere with the wrist joint motion.This allows individuals with hand defects who previously used prosthetic hands with fixed wrist joints to freely use their remaining wrist functionality.In the pick-and-place experiment,where blocks were moved from higher to lower locations,we confirmed that the proposed system resulted in a lower elbow position compared with the traditional prosthesis,and the number of blocks transported increased.This significantly reduced the compensatory motion of the elbow and improved the user’s performance compared with the use of a conventional prosthetic hand.This study demonstrates the usefulness of a new myoelectric prosthetic hand that utilizes the residual functions of people with hand deficiencies,which have not been utilized in the past,and the direction of its development.
