Rubber Feet Research Articles

Analisis Faktor-Faktor yang Mempengaruhi Hiperaktif Anak Kelas 4 di SDN Ciluluk II

Hyperactive behavior in grade 4 children at SD Ciluluk is a very complex challenge for educators which requires an in-depth understanding of the factors that influence it. Hyperactive behavior is an attitude in which every activity is carried out excessively or cannot control behavior in the environment within it. Believing that children become rubber feet is primarily due to biological and psychological factors. This research focuses on analyzing the factors that cause hyperactive children's behavior, highlighting biological and psychological aspects, thoroughly discussing the opinions of experts regarding hyperactive children, as well as the treatment of hyperactive children implemented by grade 4 teachers at Ciluluk Elementary School. This research aims to provide in-depth insight into the factors that can influence hyperactive behavior in grade 4 children at Ciluluk Elementary School. The expected results will certainly provide insight and solutions for hyperactive children in learning activities, especially in elementary schools, which will later be used as a reference for teachers to understand solutions for hyperactive children.

Design and control of a climbing robot for inspection of high mast lighting

PurposeThis paper aims to develop a climbing robot to help people inspect lamps of high-mast lighting.Design/methodology/approachThe robot consists of driving mechanism, suspension mechanism and compression mechanism. The driving mechanism is realized by link chains and sprockets, which are arranged opposite to each other, to form a dual caterpillar mechanism. The compression mechanism squeezes the caterpillar, and rubber feet “grasps” the steel rope to generate enough adhesion forces. The suspension mechanism is used to compensate the contraction or extension of the chains. The robot is equipped with a DC motor with a rated power of 250 W and a wireless module to communicate with the operator’s console. The dynamic model of the robot and the control strategy is derived, and the stability of the controller is proofed.FindingsThe payload experiment shows the robot can afford up to 3.7 times payload versus its own weight. Even when the payload is 30 kg, the robot can maintain a speed of the 1 m/s. The experiments also show that the tracking error of the robot reaches zero.Practical implicationsThe proposed moving mechanism has a high load/weight ratio, which is a verified solution for the cable inspection purpose.Originality/valueA rope climbing robot for high mast lighting inspection is proposed. The developed mechanism can reach a speed of 1 m/s with the payload of 30 kg, while its own weight is only 15.6 kg. The payload/weight ratio of the robot is 2.24; this value is rather good in many climbing robots reported in other renowned journal.

Optimization of passive control performance for different hard disk drives subjected to shock excitation

Laptop personal computers (LPCs) and their components are vulnerable devices in harsh mechanical environments. One of the most sensitive components of LPCs is hard disk drive (HDD) which needs to be protected against damages attributable to shock and vibration in order to have better magnetic read/write performance. In the present work, a LPC and its HDD are modeled as two degrees of freedom system and the nonlinear optimization method is employed to perform a passive control through minimizing peak of HDD absolute acceleration caused by a base shock excitation. The presented shock excitation is considered as half-sine pulse of acceleration. In addition, eleven inequality constraints are defined based on geometrical limitations and allowable intervals of lumped modal parameters. The target of the optimization is to reach optimum modal parameters of rubber mounts and rubber feet as design variables and subsequently propose new characteristics of rubber mounts and rubber feet to be manufactured for the HDD protection against shock excitation. The genetic algorithm and the modified constrained steepest descent algorithm are employed in order to solve the nonlinear optimization problem for three widely-used commercial cases of HDD. Finally, the results of both optimization methods are compared to make sure about their accuracy.

Improving the read/write performance of hard disk drives under external excitation sources based on multi-objective optimization

Hard disk drives (HDDs) are sensitive devices responsible for storing and retrieving digital information in computer systems and electronic products. In particular, HDDs of laptop personal computers (LPCs) are very sensitive especially in harsh mechanical environments. Accordingly, it is necessary to protect them against damages attributable to shock and vibration so as to reach better magnetic read/write performance. In this paper, the nonlinear multi-objective optimization method is utilized to enhance the passive control performance of rubbers through minimizing destructive effects of shock and random excitations. As a matter of fact, this investigation will focus on improving the shock and vibration isolation system with special emphasis on the role of rubber feet. A zero mean, stationary process with Gaussian distribution is applied to the base in order to consider effects of random excitation. Moreover, a half-sine pulse of acceleration is assumed as the base shock excitation. According to limitations of geometrical parameters and lumped modal parameters, twelve inequality constraints are presented. Modal parameters of rubber mounts and rubber feet are selected as design variables of optimization, and the multi-objective optimization problem is solved for three commercial cases of HDD by using non-dominated sorting genetic algorithm II (NSGA-II), which was proposed based on Pareto-optimality concept. Therefore, new characteristics of rubber mounts and rubber feet are recommended to be manufactured for the purpose of protecting HDDs against shock and random excitations.

A new approach to design safe-supported HDD against random excitation by using optimization of rubbers spatial parameters

Hard disk drives (HDDs) of laptop personal computers (LPCs) are devices vulnerable in harsh mechanical environments. Hence, they need to be protected against damages due to vibration in order to have better read/write performance. In the present study, a LPC and its HDD are modeled as a system with two degrees of freedom and the nonlinear optimization method is employed to perform a passive control through minimizing the root mean square of HDD absolute acceleration due to a base random excitation. The presented random excitation is considered as a stationary, zero mean process with Gaussian distribution. In addition, eleven inequality constraints are defined based on geometrical limitations and allowable intervals of lumped modal parameters. The target of the optimization is to obtain optimum modal parameters of rubber mounts and rubber feet as design variables and subsequently propose new characteristics of rubber mounts and rubber feet to be manufactured for HDD protection against random excitation. In this paper, a nonlinear optimization problem is separately solved for three widely-used cases of HDD by using modified constrained steepest descent algorithm (PLBA) which was extended based on sequential quadratic programming. Finally, the genetic algorithm is used to verify results of the PLBA algorithm.

Comparison of tapping machines for impact insulation class (IIC) measurement accuracy.

This study compares tapping machines from different manufacturers and age for impact insulation class (IIC) measurement accuracy. In addition to the IIC measurement accuracy, the study also compares the impact frequency and effect of different impact surfaces (steel and rubber). The tapping machines were tested in a model condo unit in accordance with impact insulation class testing standards ASTM E1007‐04 and ISO 140‐6. These standards clearly state the impact frequency and type of impact surface to be used (hardened steel). Previous testing standards did not specify the material type for impact surfaces and many older tapping machines included both steel and rubber feet. The results of this study will be presented to show the effect of age, impact frequency, and impact surface on the resulting IIC measurement for the tapping machines.

Why Do Calculators Have Rubber Feet?

Our students like using the covers of their TI graphing calculators in an inquiry-based extension of a traditional exercise1 that challenges their preconceived ideas about friction. Biology major Fiona McGraw (Fig. 1) is obviously excited about the large coefficient of static friction (μs = 1.3) for the four little rubber feet on her TI calculator cover. The angle of repose of 53° is three times the value she just obtained for a wood block on the same plane. That block fits nicely inside her calculator cover. By using the string already attached to the block, the cover with the block inside can be pulled along the board at a constant speed to obtain the coefficient of kinetic friction μk for rubber on wood (Fig. 2). Results vary with the age and condition of the rubber feet. Observations with only three rubber feet on some covers help to reinforce the idea that the friction force is independent of the area of the surface in contact. (Students first study the effect of area by working with the wood block on its wide side and then on its narrow side.)

Mechanical testing of prosthetic feet utilized in low-income countries according to ISO-10328 standard

This report summarizes the results from 1132 ISO-10328 standard tests performed on 21 different prosthetic foot models commonly utilized in the developing world. None of the tested feet passed the strictest ISO testing protocol. All but one failed at the initial Static Proof test, which simulates a single momentary overload, due to permanent forefoot deformation. In addition, all tested feet had significant internal failures that were visible when sectioned longitudinally. Static Proof testing revealed average permanent deformation of the forefoot of all feet that exceeded the optional 5 mm ISO requirement. Forefoot deformation for non-Jaipur rubber feet came closest to meeting the standard at 8.3+/-3.4 mm; deformation of the various types of rubber Jaipur feet was the greatest at 22.5+/-5.4 mm. Forefoot deformation for polyurethane (PU) feet was 13.6+/-5.5 mm. Forefoot deformation of the ethyl-vinyl-acetate (EVA) feet was slightly greater than the Jaipur feet at 22.8+/-5.7 mm. After the Static Strength test, which simulates a higher momentary overload, permanent deformation of the feet increased. The average maximum deformation for rubber SACH forefeet varied from 17 - 30 mm, and 11 - 26 mm for the heel; Jaipur forefeet 47 - 60 mm and heels 13 - 19 mm; PU forefeet 20 - 44 mm and heels 20 - 33 mm; and EVA forefeet 33 - 50 mm and heels 16 - 31 mm. After completion of the Cyclic Test the prosthetic feet were sawn in half and closely examined visually. All feet revealed internal derangements: (i) Deformation of rubber or PU foam under the keel of forefoot and/or heel: HCMC, VI, EB1, BAVI, HI Cambodia, Myanmar, Angola, TATCOT, Kingsley and CR; (ii) Delamination from the keel: Mozambique, PHN, and Pro-cirugia; and (iii) Delamination between foam layers: BMVSS, NISHA, MUKTI, and OM. The influence of the two environmental factors tested was minimal for rubber feet with respect to deformation and inconsistent for the polymer feet; in particular for the forefeet. Creep increased with humidity exposure in some feet of natural rubber. However, creep decreased with ultraviolet (UV) exposure for these natural rubber feet, as was also the case for EVA feet, whereas the creep increased for two PU feet. Comparison of the effect of humidity and UV exposure generally showed less creep with UV exposure. In conclusion, ISO-10328 testing prior to release of a new foot construction for amputee use appears to be useful in the developing countries as well as in the developed world, even though it does not simulate the wear on the plantar surface that is seen clinically in barefoot walking. Inspection of the internal structures after the laboratory testing has been shown to reveal occult failure mechanisms in all tested feet.

Clinical Field Testing of Vulcanized Jaipur Rubber Feet for Trans-Tibial Amputees in Low-Income Countries

The purpose of this study was to check out the performance and durability of vulcanized Jaipur rubber feet in tropical areas of the developing world. Forty-one MUKTI and 40 NISHA feet were followed for 16 (8 - 17) months. The user compliance was high and nearly all were satisfied. Failure of the prosthetic foot with the need for exchange at the end of the study amounted to 27% (22/81), which is equivalent to a mixed series of rubber feet previously reported (Jensen et al. 2006b). Failures were mostly related to skin fracture and gliding between sponge rubber layers of the heel block.

Clinical Field Testing of Vulcanized Rubber Feet for Trans-Tibial Amputees in Tropical Low-Income Countries

In a prospective, controlled study, 186 prosthetic rubber feet of different designs were fitted to amputees with trans-tibial prostheses. There were 158 amputees available for follow-up. The amputee compliance was good and 89% were satisfied with their device. After 18 months of use one VI-Solid rubber foot from VVAF in Cambodia had failed, as compared to 11% failures with the same foot with a heel cavity, 3% with the EB-1 sandwich construction from POF in Vietnam, all performing significantly better than the 62% encountered with the vulcanized rubber foot from ICRC in Cambodia; the latter representing half of the feet failing in amputees walking bare-footed. Nearly all failures were located at the foot-sole or the keel. The failure rate was 20% for the HI-Cambodia foot after 12 months. After 24 months of use, still only one VI-Solid rubber foot had failed and this foot design was found superior to the others in regard of durability.

Antivibration Electrode Support for Shipboard Stripping Voltammetry

Cathodic stripping voltammetry (CSV) is subject to interference by engine vibrations when used on-board ship. Scanning wave-forms utilizing high-frequency potential modulations can to some extent overcome this problem, but these cannot be used for catalytic CSV without major loss of sensitivity. To minimize the effects of vibrations an antivibration electrode support was developed based on a PVC plate suspended from elastic bands. The support was compared to the more simple expedient of placing the electrode on large rubber (“Hi-Fi”) feet. Successful damping was evaluated from ship-board determinations of iron in seawater by catalytic CSV. The rubber feet were found to lower the relative standard deviation (RSD) of these measurements to 34 % from 70 % without damping. The antivibration support was found to lower the RSD to an acceptable 10 % and was used extensively for voltammetry on-board ship.

The Niagara Therapy Bench for Children

VIBRATING benches are currently in use at Tudor House Nursery, Liverpool, to facilitate treatment of children under five years old who have cerebral palsy. Niagara therapy benches are robustly constructed and covered in flame retardant and easily cleaned vinyl. Rubber feet reduce transmitted vibration and prevent sliding. The vibration they provide is of variable frequency between 15-30 Hz, and has the physiological effect of reducing spasticity through muscle relaxation. The frequency is controlled by a switch sited underneath the bench, out of reach of little fingers. A separate hand-held unit houses the on/off control. The benches are 5 0 cm long. Their height and width are determined by the size of the users, and the manufacturer will supply to suit individual needs. The height should allow the children to sit comfortably with both feet flat on the floor, wi th hips and knees at right angles. As the children usually sit astride the benches, careful consideration must be given to their width, as excessive hip abduction would lead to increased flexion at the hips. To give an example of dimensions, one of the benches currently in use with children aged three to four years, is 18 cm high and 18 c m wide. The benches have now been in use at Tudor House for 2 ?h years, and have the following benefits: