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This paper analyses the potential and electric field distribution of three different variations of 11 kV polymeric insulators. The 2d models differ from each other by its shed diameter, creepage length, shed spacing, and the number of sheds. The impact of rainwater droplets, uniform, and non-uniform wet pollution on the electrical behaviour of insulator models are discussed. The environmental stresses are artificially modelled on the insulator surface. Simulations are carried out on the polymer models using COMSOL Multi-physics software, and the variation of electric field and potential distributions w.r.t creepage distance are evaluated. The influence of shape, size, and location of water droplets on the field distribution is also studied. The obtained electric field and potential distributions of the three different insulator models are compared to obtain the best configuration which would perform better than others in these environmental stress conditions.

A new kind of cleaning agent for aging insulators in power grid was reported, which can recover its hydrophobicity and insulation performance. The effects of different nonionic surfactants and repairing agents contents on the surface tension, washing efficiency, insulator contact angle, post washing hydrophobicity, post washing loss and transference of hydrophobicity were investigated. Experiments show that the cleaning efficiency is best when the nonionic surfactants content is 3%, and the average contact angle of the insulator after washing is about 126°. When the content of the repairing agent is 11%, its performance is the most superior in all aspects, and its hydrophobicity is the best, which can reach the HC1 level.

the traditional insulation design and manufacturing process of the dry-type transformer still have the defects, and the hidden danger caused is a serious threat to the long-term safe operation of the transformer. In this paper, the insulation mode of the traditional dry-type transformer and the application of the new insulating material of high-strength silicon rubber are analyzed. The concept of the main backup multi-insulation design in the combined insulation is put forward, and the solid insulation system of the dry-type transformer is strengthened by the precise design and the defect-free manufacture. The safety and the reliability of the dry-type transformer are substantially improved, the contradiction of the insulation safety and the energy-saving design is solved, and the performance of the dry-type transformer is improved by a new step.

An effort to reduce the overhead line outage due to encroachments like trees and kites, by covering the conductor with silicone rubber has been proposed. Models have been developed to simulate the ampacity and the sagging of conductor before and after the addition of silicon rubber cover. The model represents a 240mm2 ACSR (Aluminum Conductor Steel-Reinforce)-Hawk conductor with thicknesses of the cover of 4, 5, and 6 mm. As a result, the addition of silicon rubber can reduce the ampacity up to 17%, and the height of the sagging increases by 38%.

Hydrophobicity and flashover strength are important properties of outdoor insulators, especially in the tropic region, which have high pollution and high intensity of rainfall. This study examines the impact coal fly ash as a micro filler on static hydrophobicity and DC dry flashover strength of the silicon rubber. The used material is XLR silicon rubber, and coal fly ash (CFA) micro filler. Samples were grouped according CFA filler loading, which consists of six groups CFA filler loading. The result shows that the addition of CFA micro filler affects surface resistivity, the hydrophobicity, and flashover strength of silicon rubber. The hydrophobicity which is presented by contact angle increases with the increasing of filler loading. However, in high filler loading, the hydrophobicity tends to decrease. The similar trend occurs on flashover strength and surface resistivity.

With the purpose of understanding more and more the causes of fault for MV cable-joints this paper deals the interfacial pressure vs. temperature issue. By starting from results obtained by the authors in the field of cable- joints, firstly a test bed for pressure measurements is developed and characterized. Afterwards temperature test cycles have been defined to measure how temperature affects the interfacial pressure (XLPE/Silicon rubber) inside the cable-joints. Presented results confirm the accuracy of the developed setup and the pressure vs. temperature behaviour of two different cable-joints.

In this study, we propose a novel cantilever structure integrated with a high-sensitive and -reliable crack sensor that monitors the contractile behavior of cardiomyocytes in media. Si rubber with excellent performance in cell adhesiveness was used as the cantilever material. The proposed crack sensor formed on the Si rubber cantilever is chemically bonded with the PDMS thin layer to produce a sandwich structure. The protection layer greatly improves the reliability and stability of the crack sensor in the electrolyte solution. The high-sensitive crack sensor stably measures the contractility of cardiomyocytes without changing a gauge factor for up to 26 days.

Investigating of insulator performance is a continuing concern within the power system, so the study of the insulator parameters is required. The present paper aims to use new criteria and approach to predict the occurrence of flashover of (100 * 60 mm) plates of silicon rubber insulator using harmonics component of leakage current. the signal of leakage current of insulator with different pollution levels was measured under different weather conditions. Furthermore, to evaluate the effect of weather variables, various values of water conductivity were used for the experiments. The new criteria (Ki) is ratio of sum of leakage current harmonics value at frequencies 0-100 Hz to sum of leakage current harmonics value at frequencies150-500 Hz have determined. The proposed criteria can be used as wireless diagnostic tools for contamination levels flashover can occurred. Test was conducted by two wetting methods of sample SIR insulator is spray and dipping, different voltages 7kV and 14 kV have been applied. Test results shown high performance of this method.

Several failures of high-voltage and extra-high-voltage cable joints have been reported in China. It is postulated that improper pre-expansion of the cable joints before installation on the cables played a major role in the breakdowns. In this study, the researchers used two 110 k V silicon rubber premolded cable joints as experimental samples. They were subjected to different expansion rates before installation onto a cross-linked polyethylene cable cross-linked polyethylene. Two different specifications of expanding tube were used to expand the joints. Then, withstand voltage tests and partial discharge (PD) tests were done at room temperature and high temperature (95 to 100°C) according to IEC 60885–2. Statistical parameters and patterns were recorded during the test. The joint assembled with an improper expansion rate during pre-expansion installation failed to pass the PD test. The PD behavior was clearly affected by the voltage and temperature during the test. On the basis of these results, the authors propose recommendations for the installation of 110 kV silicone rubber premolded cable joints.

In order to meet the needs of the smart wearable devices for strain and curvature detection, a flexible strain/curvature sensor with simple structure and convenient manufacture technology is designed by using silicon rubber and gallium-indium-tin alloy. The basic structure of the sensor is proposed and the working principle of the soft sensor is demonstrated. Moreover, the mathematical model of this strain/curvature sensor is defined to analysis the corresponding relationship between strain/curvature and the rate of resistance change. Finally, the production process of the experimental prototype system is given and the discussion of the proposed structure is illustrated.

We present simulation results of rolling a baton on a series of circular cylinders. Realistic materials such as PVC sheets for the cylinders and wood or silicon rubber for the baton are used to find physical parameters with which the baton rolls over the cylinders. We found sets of feasible parameters of frictions and initial forces given to the baton.

Composite power station casing like DC wall casing, transformer casing, runs under long term heat conditions. Heat aging plays a major role in the aging phenomena of silicone rubber material, which is always used as composite casing sheds and sheath. Meanwhile, heat aging is also a important research method to manually accelerate the aging process of SiR for laboratory simulation. At present, study about the influence of heat aging temperature and time on the outer insulation properties of different kinds of SiR is still few. In this article, changes of static contact angle, hydrophobicity transfer ability, water classification and hardness of HTV, LSR and RTV under different aging temperature and time were measured. FTIR and XPS were used to analyze the specimen in order to explore the changes in its micro-physicochemical property. The study result shows that with the rise of aging temperature, the static contact angle of HTV and LSR showed a tendency to rise first and fall then. After heat aging, there was obvious decline in the hydrophobicity transfer ability of SiR, and hardness of different kinds of SiR showed a tendency to rise with the addition of aging time. The results of FTIR and XPS shows that for HTV, there was obvious rise in the absorption peak of O-H, but the peak of major elements changed little. For LSR, the absorption peak of major groups changed little, but the peak of O, C and Si declined and moved.

The research related to the needle force insertion modeling were limited by using a single object to support the desired performance value. In this paper, we proposed the comparison of two different of tissue objects i.e. beef liver as ex-vivo tissue and silicon rubber as phantom tissue. Experiment was performed by 1-DOF haptic feedback simulator. For the speed range 5,11–6,46 mm/sec, interaction between needle and tissue giving the same behavior but different in the details value. Therefore, by utilizing our proposed models, the application of haptic feedback simulator system should be considered for further development.

Water droplets on the surface of silicon rubber were investigated under the influence of non-uniform electric fields. Several parameters of water droplets were investigated, such as the positioning of the droplets regarding the electrodes. The most striking conclusion is that the flashover voltage and electric field distribution depends on the positioning of the droplets from the electrodes.

This research is conducted to assess condition of ceramic insulator with and without silicone rubber coating after 5 years naturally aged in Pangandaran coastal area, West Java, Indonesia. Laboratory testing is also conducted by applying voltage 11–50 kV with high humidity salt fog to the insulator and measuring the leakage current. From the data of magnitude and leakage current waveform of the leakage current, the harmonic content was taken to characterize surface condition of insulator. For higher voltage, it was found that the coating significantly reduced the corona intensity. From the result, ceramic insulator coated with silicone rubber has significant effect especially when installed in a coastal area.

In haptic perception information is often sampled serially over a certain interval of time. For example, a stimulus is repeatedly indented to repeatedly estimate its softness. Albeit such redundant estimates are equally reliable, they seem to contribute differently to the overall haptic percept in a comparison task. When comparing the softness of two silicon rubber stimuli, the within-stimulus weights of estimates of the second stimulus' softness decrease during the exploration. Here we test the hypothesis that such decrease of weights depends on the representation strength of the first stimulus' softness. We varied the length of the first stimulus' exploration. Participants subsequently explored two silicon rubber stimuli by indenting the first stimulus (comparison) 1 or 5 times and the second stimulus (standard) always 3 times. We assessed the weights of indentation-specific estimates from the second stimulus by manipulating perceived softness during single indentations. Our results show that the longer the first stimulus is explored the more estimates of the second stimulus' softness can be included in the comparison of the two stimuli. This suggests that the exploration length of the first stimulus determines the strength of its representation which influences the decrease of weights of indentation-specific estimates of the second stimulus.

Polymeric materials are generally made up of two types ethylene propylene dine monomer (EPDM) and silicon rubber(SR). Though composite insulators have shown good performance in hostile environments but silicon rubber have reduced contamination problem to some extent. Hydrophobic property of silicon rubber does not allow the surface to get wet and hence contamination does not occur. This paper presents some laboratory tests performed on silicon rubber insulators to ascertain the aging. Aging properties of the polymeric materials have been studied using inclined plane test. In inclined plane test pollution of different severity was coated on the surface of polymer and proper severity was determined for the ageing. Hence aging parameters which influence aging has been studied.

This paper proposes a haptic module for simulation of catheters used in GI (gastrointestinal) endoscopy. The designed haptic interface provides translational force feedback in one degree-of-freedom using the pneumatic module made of silicon rubber. The pneumatic module has a cylindrical shape with a hollow space inside. The space inside of the module can be filled with air activated by a syringe pump. The module grasps the catheter traveling through the module. The syringe pump is controlled to insufflate or remove air into the space in real-time. Experimental results show that the feedback force and the amount of injected air to the module have a linear relationship. The proposed interface is able to generate necessary force feedback during catheter simulation.

In this paper, an artificial neural network (ANN) has been used to compare the pollution level of aging long-rod silicon rubber and porcelain insulators. High regression values and effective correlation of equivalent salt deposit density (ESDD) have been found using MATLAB neural network toolbox. It has been found that the bottom surface of the porcelain insulator contains more pollution than the top surface. Higher pollution has also been measured in case of silicon rubber (SiR) insulator. Pollution levels in case of both insulators have been found to be exceptionally high compared to IEEE and CIGRE standards.

With the advent of robotic gripping devices pertinent to manipulation science, micro-object manipulation has become the most challenging one. In this research paper a novel technique is introduced in the field of smart actuator based finger design, for micro gripping and soft object handling. The finger were fabricated by silicon rubber (Resibond GP Sealant 1010) substrated with Ionic Polymer Metal Composite (IPMC), were totally placed within the fingers which seems to be a new approach introduced in this research report. The electrical connection of these fingers was made in a unique method and IPMCs are actuated with a satisfactory actuation result.

Insulators plays a vital role in electrical transmission line. It gives a support and separate electrical conductors and these insulators are most commonly made up of porcelain. These insulators gets polluted when they are placed near different atmospheric condition like coastal, desert etc. Now-a-days porcelain insulators are replaced by the silicon rubber insulators due its hydrophobicity property. The design parameters of silicon rubber insulator such as creepage factor, profile factor also contributes the pollution flashover. In order toassess the pollution severity level and to prevent the unpredictable flashover voltage, it is important to predict the flashover before it takes place. In this paper, four different types of 11 kV silicon rubber insulators were taken and solid layer method was used in artificial pollution test, in which sodium chloride and kaolin are used to induce the conductivity. Using even rising method, the flashover voltage has been obtained for different equivalent salt deposit density (ESDD) values. By using artificial neural network(ANN) and least square support vector machine (LS-SVM) flashover voltage has been predicted with the input parameters such as height, creepage length, diameter and ESDD. Finally, it is concluded that the LS-SVM approach has better ability to assist the flashover voltage prediction than ANN.

This research highly focuses towards development of a Shape Memory Alloy based micro valve and actuation using LASER. Numerous Micro valve designs have been reported with a variety of actuation mechanisms such as piezoelectric, silicon rubber, etc. [1], but the use of these micro valves have been limited. Here LASER is used as actuation medium because of noncontact type and low power energy density source.

Properties of acoustic signals emitted from PD sources in solid dielectrics are less well known in comparison with those in liquids. We have investigated three materials used typically as insulation in high voltage cables and their accessories, namely, polyethylene (PE), silicon rubber (SiR) and ethylene-propylene-diene monomer (EPDM). Several simple geometries of defects were considered, such as spherical voids, cylindrical cavities and fissures. COMSOL Multiphysics software was used to conduct computer modelling of acoustic emission caused by PDs in such defects. A relationship between defect dimensions and frequency of the acoustic signal emitted was established. In spherical voids and cylindrical cavities f ~ 1/d, where d is the void size. In fissures, f ~ 1/(t 0.37 w 0.5 ), where t is the fissure thickness and w is the fissure width.

The presence of unwanted constituent on insulator surface of transmission tower plays an important ignition property for the likelihood of occurrence of flashover. In this paper, the pollution level of two aged insulators namely the longrod silicon rubber and the cap-and-pin glass insulators are measured. The results from the measurement shows that the Equivalent Salt Deposit Density (ESDD) of the cap-and-pin glass insulator, particularly near the pin is found to be 0.169 mg/cm2 while the composition over the cap surface is 0.136 mg/cm2. For the case of longrod silicon rubber insulator, the ESDD for both the pin and the cap are found to be 0.063 mg/cm2 and 0.016 mg/cm2 respectively. The outcomes from the ESDD measurements suggest that the cap-and-pin glass insulator string is severely contaminated with salt spray as compared to the longrod silicon rubber. Furthermore, a mathematical model of ESDD expressed in terms of salinity and temperature for both insulators is derived from multivariable regression method. The coefficients for both the cap-and-pin glass and longrod silicon rubber insulator are found to be 0.9984 and 0.9867 respectively.

Composite Insulators exposed to atmospheric environment with pollution and ultraviolet rays for long-term would become aging. Hydrophobic was an important parameter of the composite insulator characteristics. Under the impetus of the STRI laboratory, the static contact angle evaluation method had been changed by receding angle evaluation method internationally. China could not be directly used, the two method needed to be compared. On this basis, the receding angle method and the static contact angle method were compared which was focus on the evaluation of the operability of this method, the selection of the evaluation criterion and the reasonableness of evaluation criterion. The results show that the receding angle in the three aspects is not mature. The receding angle method should not be used to replace the static contact angle method at this time.

For long-term operating outdoor insulation, contamination accumulation has become an increasingly serious problem. In this paper, atomic force microscopy was used to measure the adhesion force of glass, silicon rubber, porcelain, stalinite samples. Test results showed that adhesion force of silicon rubber was the largest, approximately larger than the other three samples by one or two orders of magnitude. Furthermore, silicon rubber surface exhibited a long-range attractive force and multiple points contact, probably due to the electrostatic interaction and surface roughness. It might be a theoretical proof which accounts for the different contamination accumulation between composite insulator and porcelain or glass insulator.

This study constructs a novel blood pressure measurement device without the air cuff to overcome the problem of discomfort and portability. The proposed device measures the blood pressure through a mechanism that is made of silicon rubber and pressure transducer. The system uses a microcontroller to control the measurement procedure and to perform the necessary computation. To verify the feasibility of the constructed device, ten young volunteers were recruited. Ten blood pressure readings were obtained using the new system and were compared with ten blood pressure readings from bedside monitor (Spacelabs Medical, model 90367). The results indicated that, when all the readings were included, the mean pressure, systolic pressure and diastolic pressure from the new system were all higher than those from bedside monitor. The correlation coefficients between these two were 0.15, 0.18 and 0.29, for mean, systolic and diastolic pressures, respectively. After excluding irregular apparatus utilization, the correlation coefficient increased to 0.71, 0.60 and 0.41 for diastolic pressure, mean pressure and systolic pressure, respectively. We can conclude from these results that the accuracy can be improved effectively by defining the user regulation more precisely. The above mentioned irregular apparatus utilization factors can be identified and eliminated by the microprocessor to provide a reliable blood pressure measurement in practical applications in the future.

soft skin artefacts made of knitted nylon reinforced silicon rubber were fabricated mimicking octopus skin. A combination of ecoflex 0030 and 0010 were used as matrix of the composite to obtain the right stiffness for the skin artefacts. Material properties were characterised using static uniaxial tension and scissors cutting tests. Two types of tactile sensors were developed to detect normal contact; one used quantum tunnelling composite materials and the second was fabricated from silicone rubber and a conductive textile. Sensitivities of the sensors were tested by applying different modes of loading and the soft sensors were incorporated into the skin prototype. Passive suckers were developed and tested against squid suckers. An integrated skin prototype with embedded deformable sensors and attached suckers developed for the arm of an octopus inspired robot is also presented.

This paper presents the analysis of potential and electric distribution characteristics of outdoor polymer insulator. Silicone rubber provides an alternative to porcelain and glass regarding to high voltage (HV) insulators and it has been widely used by power utilities since 1980's owing to their superior contaminant performances. Failure of outdoor high voltage (HV) insulator often involves the solid air interface insulation. As result, knowledge of the field distribution around high voltage (HV) insulators is very important to determine the electric field stress occurring on the insulator surface, particularly on the air side of the interface. Thus, concerning to this matter, this project would analyze the electric field distribution of energized silicone rubber high voltage (HV) insulator. And the simulation results of electric field and potential distributions along surface of silicone rubber polymer insulators under clean and contamination conditions. For comparative purposes, the analysis is based on two conditions, which are silicon rubber insulators with clean surfaces and silicon rubber insulators with effect of water droplets on the insulator surface. Finite element method (FEM) is adopted for this work. The electric field distribution computation is accomplished using MAT LAB-PDE TOOL software that performs two dimensions finite element method. The objective of this work is to comparison of both the alternative shed and straight shed type insulators under the effect of contamination on potential and electric field distributions along the insulator surface when water droplets exist on the insulator surface

Sound localization is one of fundamental abilities of auditory robots that is necessary for human-machine communication. Especially for autonomous robots, it is also necessary to make the system as simple as possible, and binaural configuration is thought to be the minimum setup for auditory systems as animals achieve practical hearing with two ears. However, the limitation of the number of ears leads insufficient performance such as accuracy in sound localization, or sound source separation. In order to overcome those difficulties, this paper proposes a novel artificial soft pinna that can move, or deform its shape actively. The developed pinna has deformable skin of silicon rubber with wires controlled by motors, and it is covered by a fur cover. Considering applications of the proposed device for auditory robots, fundamental characteristics such as accuracy of motion and auditory characteristics were investigated through experiments, which is the main contribution of the paper.

We have already developed a haptic device using flexible sheet such as rubber. This device varies sheet compliance by controlling tension applied to the sheet: stretched sheet feels hard, and loose sheet feels soft. Hence a user can feel different compliance of virtual objects when he pushes the sheet directly with his finger. In the present study we propose a new haptic device which can move, expand and narrow the touch area on the sheet in addition to tension control. This device has two movable bars slightly touching the back of the tensioned sheet. A user touches and pushes the area between the bars on the sheet. Because the bars work as supporting struts, only this area is depressed. Controlling the distance between the bars varies the size of the touch area, thus varying sheet compliance: wide area makes the sheet soft, and narrow area makes the sheet hard. Keeping the size of the touch area constant generates the same sheet compliance, even if the touch area moves anywhere. Owing to the effects of variable tension and touch area, the new device can generate more variety of compliance than the previous one. A prototype device using a silicon rubber sheet is developed. Four servo motors move two bars through parallel link mechanisms under the tensioned sheet. The force-indentation curves for some sets of different tension and touch area are measured. The results show that the developed device can generate wide range of sheet compliance.

Ozone is one of the byproducts when there is corona occurred in the air. In order to study the influence of corona on the aging of HTC silicone rubber, the TSC performance of HTV silicone rubber under ozone environment has been investigated in this paper. This paper mainly reported the influence of the different ozone aging time. The relationship between the TSC performance and the ozone aging time has been investigated using HTV silicone rubber samples. The experimental results show that the sample's TCS would be changed after the Ozone treatment. There were more traps along with the corona deterioration process of HTV silicon rubber, and the trap level would be increased too.

In this experiment we investigated the influence of stimulus properties on exploratory movement parameters in active touch. More precisely, we investigated whether and to what extent variations in stimulus compliance influence the executed finger force and velocity of the exploratory movements. Therefore, we varied the compliance of silicon rubber stimuli with deformable surfaces. Participants freely explored pairwise presented stimuli with a bare finger, and were asked to select the softer one. We found that both exploratory force and velocity depended on the compliance of the stimulus. Our results suggest in particular that observers strategically adapt their maximum finger force to the expected softness of the stimulus.

Concrete-polluted silicone rubber (SIR) insulators are common nature-polluted insulators. A type of concrete-polluted SIR insulators with different content of concrete was evaluated. The flashover voltage of concrete-polluted insulators was tested after placing in artificial climatic chamber for 6 hours with ultrasonic fog device continual working. The incepted discharge area always occurs at the umbrella edge and the connected area of the hardware fittings and core rod for light concrete-polluted SIR insulators. However, the incepted discharge area always occurs at connected place of core rod and hardware fitting for heavy concrete-polluted one. The flashover voltage decreases with the increase of concrete content by a power function and the influence factor of the concrete deposit density b is 0.194. Even though after a long time transfer, the hydrophobicity of heavy concrete-polluted SIR insulators also decrease with the increase of concrete-polluted content.

The paper presents the results of comparative tests of model composite insulators with housings made of HTV silicon rubber and sheds inclined at different angles (0deg, 10deg, 30deg). The main aim of the tests was to acquire experimental data for an assessment of the effect of the shed inclintion angle on the ageing degradation of composite insulators under high voltage in rain and fog conditions. The insulators were exposed to AC (50 Hz) voltage and water precipitation in a rain chamber and in a fog chamber. The tests showed clear differences in ageing times between insulators, leading to increased leakage current and surface electric discharges. It was found that the insulators with a large shed inclination angle (30deg) have a higher ageing resistance, particularly in rain conditions.

A hydrogel-actuated microvalve that responds to changes in the concentration of glucose in an external liquid environment is described. The microvalve consists of a thin hydrogel, sandwiched between a stiff porous membrane and a flexible silicon rubber diaphragm. Swelling of the hydrogel forces the membrane to deflect therefore boss causes the valve to be opened. Simulations have been done by FEM analysis and the results show enough deflection to open the valve and let the fluid flow through the microchannel to obtain 130 microliter/min for output flow.

Solid insulators breakdown mechanism is always associated with surface leakage current. Surface leakage current causes surface tracking. Surface tracking in non-ceramic insulators is an unwanted phenomenon, which cannot be accurately predicted. This paper introduces an experimental and analytical technique to predict the insulator life time, and presents an experimental measurements of the surface leakage current against time of non-ceramic insulators on naturally aged insulators and artificially contaminated material. A comparison of surface leakage current for fourteen different type of non-ceramic materials under the same conditions is also introduced in this paper (the mentioned non-ceramic materials are mainly Silicon Rubber (SR) and Poly Propylene (PP), with different filler percentage). The study of the leakage current dependence on the insulators contamination level is also presented in this paper. Different prototype of Artificial Neural Networks-based system that can estimate the insulator age under different contamination level at the surface of polymer insulators by employing the experimentally measured leakage current was constructed in this paper. The proposed prototype is trained for different filler level for different insulator type in the neural network. The proposed technique in this paper predicts the best non-ceramic insulator with the exact filler percentage that withstands higher voltage with longer life time under contaminated weather and polluted condition. The proposed technique is considered to be helpful tool in the area of quality control.

In this paper we present the Mexican design for a penile prosthesis. The material proposed is medical grade silicon rubber and the desi n proposed is based on three existin prostheses. #is design fulfills the specifications of the Mexican population in general.

In this work, a new model, able to emulate the interaction of a robot with the environment when viscoelastic phenomena occur, is presented. The starting point of this research activity has been the study of soft pads for dexterous manipulation but the results obtained are applicable to all situations which foresee the interaction of a robotic manipulator through/with a viscoelastic medium (e.g. robotic surgery). Based on the so called quasi-linear model, adopted to describe the behaviour of human hand pads and, more generally, of biological tissues, this model allows to overcome the problems tied to classical (linear) models, often used in the robotic field. A procedure aiming to obtain the parameters of this nonlinear model is developed on the basis of classical identification methods and of physical insights. Finally, through experimental tests on some viscoelastic materials (a polyurethane gel and a silicon rubber) the model is validated.

In this paper, we propose a new type of contact force sensor. This sensor can detect contact location and can measure four-axis contact forces. The contact part of this sensor is composed of a silicon rubber, allowing this sensor to contact to objects softly. The structure of this sensor and the methods for calculating the contact location and the four-axis contact forces are proposed. A flexible structure is one of the characteristics of this sensor. We confirm if this character is available to absorb impact force when the sensor and environment are in contact. In addition, the effectiveness of this sensor in a task involving the grasping of an object by a robot hand is also demonstrated.

Patterns of electrical trees in insulators have been investigated numerically using fractal dimension. The complexity of the pattern of the tree increases with applied voltage. The degree of the complexity depends on the polarity of the applied voltage. The change of the pattern of the tree can be indicated by the fractal dimension. However, in high voltages the fractal dimensions of the trees are almost same one in both polarities. This means that the pattern of the tree consist of some fractal patterns. Thus we must focus on the local pattern of the tree which is estimated by local fractal dimension. In this paper, the pattern is analyzed by the local fractal dimension method, i.e. local fractal dimension map and local fractal dimension spectrum. The needle electrode in a silicon rubber has been applied three or four times with impulse voltage. The local fractal dimension maps and its spectra have been compared and then the next growth of the tree or branches has been predicted using the local fractal dimension map. In addition, the change of the local fractal dimension of the tree along the branch has been investigated.

Contaminants are deposited on the insulator surface during salt fog tests. This provides a path for the leakage current to flow along the surface of the insulator. It is important to have an indication of the pollution accumulation in order to evaluate the test performance of a particular insulator. A good insulator is expected to have a smaller amount of contaminants deposited during the aging tests. The paper describes the test procedures, and presents data for various polymer (silicon rubber and EPDM) insulators. These insulators were tested under two different salt fog conditions. The positions of the insulators were either vertical or horizontal.

There are two different techniques that can be applied for fabricating a nerve cuff electrode: 1. traditionally used silicon rubber tubes or spirals and 2. micromechanical methods. Each technique has its own advantages and restrictions. A hybrid cuff combines desired properties of both: high flexibility, high possible numbers of integrated electrodes, high reproducibility and the ability to embrace nerves even with large diameters.

Preliminary observations concerning a novel approach proposed by the authors for carrying out a screening of outdoor insulating materials by low-cost medium-term experiments are presented. The purpose of this approach is to carry out selection among materials of the same family using a reference material (belonging to that family) whose behavior has already been evaluated by means of tests on full-size insulators. A fog-chamber test and three different inclined-plane test procedures were used to perform a comparison among different epoxy systems and silicon rubber systems. >

This paper describes a new three-axis tactile sensor equipped with an optical waveguide plate mounted on a robot manipulator. After a series of FEM contact analyses and evaluation experiments were conducted, an experimental large-sized tactile sensor intended for employment in evaluation experiments was designed and produced. The experimental results confirmed that the tactile sensor is capable of detecting the distribution of three-axis force and that the calculated and experimental results coincide well. On the basis of these results, a smaller tactile sensor mounted on a robot manipulator was designed and produced. This tactile sensor comprises a CCD camera, a light source, an acrylic board and a silicon rubber sheet that are assembled into a casing 180 mm long, 80 mm wide and 50 mm thick.

A malleable penile prosthesis made from silicon rubber, having one end fixed and the other free, is treated as a long column with end loading. It is found that this prosthesis can withstand a load of about 300 lb, deflecting only 0.3 mu m. During the experiment, the prosthesis was loaded without any muscle structure surrounding it. Once placed inside an actual penis with the muscles intact, the total girth of the penis increases, which helps it to carry a load beyond 185 lbs, so the prosthesis is safe in design. >