Hanie Nadia Shasmin

A Preliminary Study of Acceptable Load Carriage for Primary School Children

This study investigated the changes in Ground Reaction Forces, GRFs and trunk inclination among primary students when carrying heavy backpacks. A randomised controlled experimental study was conducted on seven boys aged between 9 and 11 years old with similar Body Mass Index. Observations were done when the boys were carrying school bags of 0 (as control), 10, 15 and 20% of their own body weight whilst normal walking. Data acquisition was carried out using force platforms and 3-D motion analysis system. A significant difference in Ground Reaction Forces at load of 20% of body weight was found. The vertical GRF increased almost three times when loads increased up to 20% of body weight compared to 10% of body weight. The anterior-posterior GRFs were asymmetrical when loads were increased. When carrying load of 15% of body weight, the subjects adopted a compensatory trunk inclination. If Ground Reaction Forces and trunk inclination are important as the criteria to determine the acceptable backpack loads for children, those loads should not exceed 15% of body weight.

Uniformly Porous Nanocrystalline CaMgFe1.33Ti3O12 Ceramic Derived Electro-Ceramic Nanocomposite for Impedance Type Humidity Sensor

Since humidity sensors have been widely used in many sectors, a suitable humidity sensing material with improved sensitivity, faster response and recovery times, better stability and low hysteresis is necessary to be developed. Here, we fabricate a uniformly porous humidity sensor using Ca, Ti substituted Mg ferrites with chemical formula of CaMgFe1.33Ti3O12 as humidity sensing materials by solid-sate step-sintering technique. This synthesis technique is useful to control the grain size with increased porosity to enhance the hydrophilic characteristics of the CaMgFe1.33Ti3O12 nanoceramic based sintered electro-ceramic nanocomposites. The highest porosity, lowest density and excellent surface-hydrophilicity properties were obtained at 1050 °C sintered ceramic. The performance of this impedance type humidity sensor was evaluated by electrical characterizations using alternating current (AC) in the 33%–95% relative humidity (RH) range at 25 °C. Compared with existing conventional resistive humidity sensors, the present sintered electro-ceramic nanocomposite based humidity sensor showed faster response time (20 s) and recovery time (40 s). This newly developed sensor showed extremely high sensitivity (%S) and small hysteresis of <3.4%. Long-term stability of the sensor had been determined by testing for 30 consecutive days. Therefore, the high performance sensing behavior of the present electro-ceramic nanocomposites would be suitable for a potential use in advanced humidity sensors.

In-Socket Sensory System for Transfemoral Amputees Using Piezoelectric Sensors: An Efficacy Study

This paper presents the design and evaluation of an in-socket sensory system for a transfemoral prosthetic leg using a set of piezoelectric sensors. The design process includes identifying the optimal mounting configuration of the sensors and determining their best placement. Two experiments were performed separately to address each objective. Results of the experiment suggested that cushionall with fit size cantilever with elastic foundation should be adopted to mount the sensors on the sockets wall. As for the placement of the sensors, the result suggested that the sensors should be positioned in zig-zag orientation from top to bottom, which can cover all of the most active area on the quadriceps and hamstring muscle groups. With the identified design, the socket was fabricated and instrumented for a transfemoral amputee and the performance of the in-socket sensory system was evaluated. The amputee performed level walking at normal speed on a 5-m straight pathway multiple times while the output voltage signal from each sensor was recorded. The output signals consistency was assessed by calculating the cross correlation, r, within five trials. In order to measure the strength of the correlation matrix of each sensor, the Frobenius norm, ||A||F was calculated. The high norm value for all sensors pattern (||A||F>4.5) for quadriceps implies that the mounting and placement of the sensors is most suitable for a consistent and reliable signal. For Hamstring, results inferred that except for the two sensors located on the top most position and the most bottom sensor, the other sensors showed good performance (||A||F>4.4). Thus, the proposed design of the in-socket sensory system using piezo sensors was proven to be effective for a transfemoral prosthetic leg.

Economical Tube Adapter Material in Below Knee Prosthesis

Amputations among Malaysia citizens is increasing by 46% annually. This people are in need of lower leg prostheses but are unable to afford the high costs of current prosthetic components. In this study, bamboo will be used to replace the conventional pylon material in below knee prosthesis component. Bamboo is a natural fiber-reinforced composite material possesses good mechanical properties to warrant its use as a structural material. Literature in bamboo composites is rare. In this paper, the flexural, compressive and tensile properties of bamboo are evaluated. Further, the properties of bamboo at different culms are examined. The results show that the specific strength and specific modulus of bamboo are adequate, the former being stronger than Aluminum and other composite pylon material. The thickness and shape of the composite can be monitored during manufacture to meet specific requirements of transtibial pylon application. Although, the lifespan of this natural composite probably will be questioned, but the fatigue property will be improved throughout this study by using the chemical substances and heat treatment.

Comparison between Biomechanical Characteristics of Stainless Steel and Bamboo Pylons: A Preliminary Study

A total of 10 subjects with unilateral transtibial amputations had performed walking with tube adapter prostheses from Bamboo and Stainless Steel components. The objective of the study was to determine whether mass differences had an effect on amputees walking. Full biomechanics characteristics were analysed by using the motion analysis system. Further, energy cost and mechanical power of transfers within and between segments were calculated during steady state walking at self selected velocities. The study of biomechanical characteristics and energy expenditure of lower extremity amputations between these two types of shank prostheses was a continuous study from development of transtibial pylon from low cost material. The results indicated that there was no significant effect to gait properties; cadence, and stride velocity. However, the older persons and established walkers benefit most from the use of bamboo components in the prosthetic legs in their energy consumption and mechanical power.

A NEW PYLON MATERIALS IN TRANSTIBIAL PROSTHESIS: A PRELIMINARY STUDY

Prosthesis is used to provide an individual who has an amputated limb with the opportunity to perform functional tasks, particularly ambulation (walking). The basic components of these lower limb prostheses are the foot-ankle assembly, pylon (shank), socket and suspension system. The pylon, which commercially made from Stainless Steel or Titanium is used to connect the socket to the ankle-foot assembly. Today, transtibial amputees have an equal number of options available in the market to fit sprinting, skiing, golf and swimming sport. However, these high-tech prostheses can cost several thousand dollars in the West and amputees from low-income countries just could not afford to buy them. Referring to the ISPO consensus conference on appropiate technology in developing countries 1995, most rehabilitation research has targeted low cost foot-ankle assemblies 1. However, in this study, the commercial pylon (shank) will be replaced by using the bamboo.

Interface Pressure of Lycra Orthosis at Different Postures in Children with Cerebral Palsy (CP)

Medical compression garment functions by exerted interface pressure between the fabric and skin. Yet, none of the previous studies have determine the pressure level of Lycra based orthosis. The current work aimed to determine the pressure level of Lycra orthosis at different postures in children with CP. Five (5) children with CP were recruited. Each were given a custom made Lycra orthosis. Two Tekscan medical sensor were placed over lateral side of upper garment and pants. The pressure was recorded when the child was in sitting, sit-to-stand (STS) and standing postures. There are significant differences of the interface pressure between each children, at different postures. The highest pressure recorded over upper garment is 122 mmHg and 120 mmHg over pants, both during sitting position. Overall, the Lycra orthosis exerted highest pressure over top garments than pants during sitting position.

Optical fiber Bragg grating-instrumented silicone liner for interface pressure measurement within prosthetic sockets of lower-limb amputees

This paper presents a fiber Bragg grating (FBG)-instrumented prosthetic silicone liner that provides cushioning for the residual limb and can successfully measure interface pressures inside prosthetic sockets of lower-limb amputees in a simple and practical means of sensing. The liner is made of two silicone layers between which 12 FBG sensors were embedded at locations of clinical interest. The sensors were then calibrated using a custom calibration platform that mimics a real-life situation. Afterward, a custom gait simulating machine was built to test the liner performance during an amputees simulated gait. To validate the findings, the results were compared to those obtained by the commonly used F-socket mats. As the statistical findings reveal, both pressure mapping methods measured the interface pressure in a consistent way, with no significant difference (P-values ≥0.05). This pressure mapping technique in the form of a prosthetic liner will allow prosthetics professionals to quickly and accurately create an overall picture of the interface pressure distribution inside sockets in research and clinical settings, thereby improving the socket fit and amputees satisfaction.