Hard Rubber Research Articles

Soft-rubber-packaged Pb(Zr,Ti)O3 MEMS touch sensors for human–machine interface applications

We proposed and developed soft-rubber-packaged Pb(Zr,Ti)O3 (PZT) microelectromechanical systems (MEMS) force sensors as human–machine interface sensors of human touch and input. To achieve small and highly sensitive sensors with low-power-consumption, a small PZT MEMS cantilever was used as the sensing element, and it was covered with soft rubber, poly(dimethylsiloxane) (PDMS), to prevent the cracking of the brittle PZT film when touching the sensor. The PDMS packaging does not affect the ferroelectric characteristics of the sensing PZT film, because the hysteresis and impedance changes of the PZT are less than 5%. The sensor dimensions are 5 × 5 × 1.1 mm3. The sensor generated charges without requiring voltage supply. The sensor generated an electric charge of 7.8 pC under an applied force of 1 N. The sensitivity was adjusted by changing the hardness of the soft rubber package: hard rubber provides high sensitivity, but the sensor is easily cracks. Hence, a sensor with a durometer hardness A of 35.6 was found to be optimal as a human–machine interface sensors of human touch of approximately 5–7 N because it has a linear sensitivity at force smaller than 5 N and the bending is small at forces larger than 5 N, which leads to a highly durable sensor. The sensor with a durometer hardness A of 35.6 did not break or crack until the applied force reached 40 N. By packaging brittle PZT MEMS cantilevers with soft rubber, small-force sensors can be constructed, leading to small, low-energy-consumption human–machine interface sensors.

Space Allowance of the Littered Area Affects Lying Behavior in Group-Housed Horses

Horses can sleep while standing; however, recumbency is required for rapid eye movement (REM) sleep and therefore essential. Previous research indicated a minimal duration of recumbency of 30 min per 24 h to perform a minimal duration of REM sleep. For group-housed horses, suitable lying area represents a potentially limited resource. In Switzerland, minimal dimensions for the space allowance of the littered area are therefore legally required. To assess the effect of different space allowances of the littered area on lying behavior, 38 horses in 8 groups were exposed to 4 treatments for 11 days each; T0: no litter provided, T0.5: 0.5× minimal dimensions, T1: minimal dimensions, and T1.5: 1.5× minimal dimensions. Non-littered areas were covered with hard rubber mats. Lying behavior was observed during the last 72 h of each treatment. The total number of lying bouts per 24 h was similar in treatments providing litter, whereas in treatment T0, recumbency occurred only rarely (F1,93 = 14.74, p = 0.0002) with the majority of horses lying down for less than 30 min per 24 h (, p = 0.0006). Overall, the total duration of recumbency per 24 h increased with increasing dimensions of the littered area, whereby the effect attenuated between treatment T1 and T1.5 in high-ranking horses but continued in low-ranking horses (F1,91 = 3.22, p = 0.076). Furthermore, low-ranking horses showed considerably more forcedly terminated lying bouts in treatments T0.5 and T1, but were similar to high-ranking horses in T1.5 (F1,76 = 8.43, p = 0.005). Nonetheless, a number of individuals showed durations of recumbency of less than 30 min per 24 h even in treatment T1.5. The lying behavior was dependent on the availability of a soft and deformable surface for recumbency. A beneficial effect of enlarged dimensions of the littered area was shown by increased durations of recumbency and decreased proportion of forcedly terminated lying bouts in low-ranking horses. Taking this into account, it became evident that the minimal dimensions for the littered area as implemented in the Swiss animal welfare legislation do not ensure undisturbed lying behavior for all members of a given group.

Rubber Bat Effect of Maximal Ball Velocity in Table Tennis

This study is focused on the analysis of the characteristics and the effects on the ball speed of smash stroke using different types of bat rubber. The types of bat rubber researched in this study are inverted, pimpled out and hard rubber. The study samples are table tennis athletes of Table Tennis Student Activity Unit at UPI Bandung. The data of the study is obtained by conducting video analysis using motion software analysis system (Frame-DIAS IV). From the result of this study, speed data of each type of bat rubber is obtained. One-way ANOVA statistical test shows that there is no significant difference on the ball speed between inverted and hard rubber types. Another result shows that there are significant differences of ball speed which are produced by using inverted and hard rubber types. Some of the factors that influence these differences are pips orientation and thickness of each rubber. This test result shows that the selection of bat rubber types is vital in improving the quality of athlete performance.

Strength calculations of perforated cylinders with combined use of the boundary element method and non-local fracture criteria

When using local fracture criteria, it is usually assumed that fracture begins when the maximum equivalent stress reaches the limit value at least at one point in the body. But under conditions of an inhomogeneous stressed state, it is advisable to use nonlocal failure criteria, which take into account the uneven distribution of stresses and give estimates of ultimate loads that are closer to the experimental data. A numerical algorithm for the strength of plane construction elements is constructed using the gradient fracture criterion and the boundary element method (the fictitious stress method). Numerical calculation was carried out with the help of a program written in Fortran. Calculation results obtained using the criterion of maximum stress, gradient fracture criterion; point stress criteria are compared both among themselves and with the experimental data. Results of brittle fracture experiments on hard rubber cylinders with a hole are presented. It is shown that the values of limit loads provided by nonlocal criteria are closer to the experimental values than given by local criterion. The estimates obtained with the help of the local criterion for maximum stresses are substantially lower than the experimental ones. The Nuismer criterion gives higher estimates of ultimate loads compared to the local criterion, but these estimates are still less than the experimental values, while the values of the ultimate load by the gradient criterion are the closest to the experimental results. The use of nonlocal failure criteria in the design of structures with stress concentrators will increase the estimates of ultimate loads.

Simulation based Sensitivity Study of Tread Pattern and Materials on Cooling Efficiency of M1 Vehicle Tyres

Tread wear of tyres is one of the serious issues in automobiles. Higher amount of heat is generated due to lesser availability of air in the tread region when the vehicle is travelling at high speeds. The existing M1 vehicle tyre has some specific standards of tread angle. In this paper, flow simulation and drop tests of M1 vehicle tyre are carried out using Solidworks. The objective of the work is to improve the cooling efficiency of tyre for vehicle speeds as 40 kmph, 80 kmph and 120 kmph. Various tread patterns for tyres made with hard rubber, Nylon66 and Nylon6 materials were simulated to predict the temperature distribution. Based on the temperature distribution and drop test results from the simulation, improved designs of M1 vehicle tyre are presented.

Pre-stressed rubber material constant estimation for resilient wheel application

This paper describes the methodology and results of the complex modulus estimation of rubber segments pressed between the disk and the rim of a rubber-damped railway wheel. The solution comes out from the method proposed and validated at rubber constant identification on the case of the steel beam with rubber layer. In the vicinity of eigenfrequency its dependence to Young modulus is quasilinear and can be solved effectively by the gradient method. The similar behavior showed itself also for dependence of the modal damping constant on the damping coefficient. The ascertained results of tuned rubber material constants, i.e. the modulus of elasticity and a loss factor, of the rail rubber segments are very valuable for prediction of modal behavior of the new resilient wheels and they are qualitatively in accordance with the behavior of hard synthetic rubbers.

Amplitude-Temperature Analysis of Hard Rubber by Torsional Vibration

This paper deals with an experimental analysis of hard rubber dynamic tests under finite torsion deformations. The experimental test rig was designed and composed for torsion loading of rubber under defined amplitudes, frequencies and temperatures. The present paper brings an amplitude-temperature analysis of isoprene-butadiene rubber ascertained by the use of the test rig. The mathematical rheological model of rubber was designed for phenomenological description and parametric identification of rubber.

Effective parameters for calculating discharge of radial gates

This study presents some theoretical relationships to estimate the discharge exiting from various types of radial gates under free and submerged flow conditions. These equations, which are based on energy and momentum concepts, were calibrated by means of a large number of experimental records retrieved from research conducted on three types of radial gates: hard rubber bar, sharp and music note gates. Results showed that the proposed equations could more accurately estimate the discharge of these radial gates where the mean absolute relative errors were less than 1·5 and 3·5% for free and submerged flow conditions, respectively. It was also observed that under specific circumstances, a hard rubber bar gate permits more discharge than sharp and music note gates. It is recognised that the discharge coefficient decreases with increase of lip angle. The reliability of the proposed equations was tested using 514 field data of multi-radial gates under operation in different irrigation canals. The study showed that calculating the total discharge exiting from individual gates by means of proposed equations was in close agreement with field observations. The predictive errors of the total flow discharge for 78% of the flow data were about ±10%.

Acute myocardial infarction due to left anterior descending coronary artery dissection after rubber bullet shooting

A 43-year-old healthy farmer received an attenuated energy projectile (hard rubber bullet probably fired by Flashball®, Verney-Carron®, France) in the left hemithorax at a close distance range during a riot.

Use of Shore Hardness Tests for In-Process Properties Estimation/Monitoring of Silicone Rubbers

Casting is an important rubber manufacturing process for both production and material developments. A quick and flexible way of testing the constitutive materials properties of rubber products is very important for optimising the processing parameters and quality control. In many cases, standard tests such as tensile or compression tests are time consuming and require a large volume of materials. This work reports some recent work in using a combined numerical and experimental approach to characterise the properties of rubber materials during a casting process. Durometer shore hardness is used to test silicone rubbers (as a model material) with different compositions on different moulding planes and the linear elastic property is estimated from the hardnesses. The predicted properties are systematically compared with the experimental tests on hard and soft silicone rubber samples with different compositions. The work shows that shore hardness can be used as an effective way to monitor the materials properties during amoulding process for process optimisation and quality control.

The Kinematic Research in the Manufacture of Rigid Polyurethane Rubber Micro-V Grooves

Based on the regularities of motion of the rigid polyurethane rubber ultrasonic vibration assisted grinding, combined with the kinematic analysis of the general theory and experiments. This paper analyses the variation in position, velocity and acceleration during the manufacture of single abrasive grinding with and without ultrasonic vibration. The impact of rigid polyurethane rubber micro V - groove process introduced by the ultrasonic vibration is explored to verify the feasibility of the ultrasonic vibration assisted grinding of micro-precision machining of hard polyurethane rubber material.

Investigation of Historical Hard Rubber Ornaments of Charles Goodyear

Charles Goodyear discovered the vulcanization process of natural rubber in the middle of the 19th century. In this paper, original ornaments produced by Charles Goodyear are investigated. Additionally, for comparison, a sample is produced according to Goodyear's patent (US 3633) as reference. Contrary to expectation, it is found that Charles Goodyear did not prepare the ornaments using the formulation of his patent, thus he excluded the white lead. Due to this, another reference sample is produced like the other but without white lead. It is proven that by artificial aging, natural rubber samples can get properties similar to the 150 years old rubber sample. image

Comparing plastic ingestion in juvenile and adult stranded short-tailed shearwaters (Puffinus tenuirostris) in eastern Australia

Numerous species of seabirds have been shown to ingest anthropogenic debris, but few studies have compared ingestion rates between adults and juveniles of the same species. We investigated marine debris ingestion by short-tailed shearwaters (Puffinus tenuirostris) obtained through two stranding events on North Stradbroke Island, Australia in 2010 (n=102; adult) and 2012 (n=27; juveniles). Necropsies were conducted and solid contents found in guts were categorized into type and color. Over 67% of birds ingested anthropogenic debris: 399 pieces of debris were identified. We found no significant relationship between body condition of birds which had ingested anthropogenic debris and those that had not. Juvenile birds were more likely to ingest debris than were adult birds and juveniles ingested significantly more pieces of debris than did adults. Male and female birds ingested similar amounts and weights of debris. To determine if P. tenuirostris actively selects for certain types of debris, we compared ingested debris to samples obtained from boat-based tows. Significant differences were found, suggesting that the birds select for hard plastic, rubber and balloons.

Teponaztli, an ancient percussion instrument

Ancient percussion instruments in Mesoamerica included the Huehuetl and the Teponaztli, both made out of a single piece of hollow trees, which pretty often were decorated with low profile representations of animals, warriors or other ceremonial symbols, both were often used by the Aztecs and Tarascas among many other cultures in the region. The first one is normally used in a vertical position and has an strained animal skin, typically an ocelot, in the top side in order to excite it with wooden sticks or by the bare hands, while the second is formed by a couple of tongues made out from the same tree cortex, and excited by a couple of wooden sticks covered with hard rubber. In both the hollowed tree forms a resonant chamber in order to increase the sound level, and include openings in order to allow the exit of the sound from inside of the drum. They were employed for ceremonies, festivities and communication. Here, there are presented the sound characteristics of a small “teponaztli,” which is actually a small copy scaled about 5:1 of a real one, which can usually only be seen in archaeological museums.

Phase Difference Technique for Material Classification by Using Tuning Fork with Piezoelectric Resonator

A tuning fork with piezoelectric (TFP) is an electro-mechanical device; its principle performance is based on specific frequency and limited voltage. As the principle, the device can result output significantly. This paper presents a material classification using phase difference value that is received from touching between material and modified TFP. For the modified TFP, it is customized by a millimeter needle. The frequency response method on Bode plot is used to observe the modified TFP behavior, and to select a specific frequency. The first-order model with cascade notch filters is employed to identify mathematical model of the TFP, and to verify the model by simulation. Experimentation is considered on 2 touching techniques: a shear-force type and a tapping mode type. There are hard plastic, iron, silicon rubber, vinyl eraser and hydrogel for test material. The results are described by both time series plots of input-output signals and numerical table of shifted phase. The technique can employed to classify the test materials effectively and explicitly.

Stress distribution experienced under a portable light-weight deflectometer loading plate

In the field of pavement engineering, the need to rapidly and economically obtain properties of soils and materials has given rise to the development of many non-destructive techniques. Portable light-weight deflectometers (PLWD) are relatively new deflection-based tools. As a consequence, the main factors influencing the quality of the results obtained using such a tool are still being investigated. Therefore, through finite element modelling and experimental measurements, this research focussed on the stress distribution and stress variability under a PLWD loading plate and how it is influenced by stress level, plate diameter, rubber mat use and rubber hardness. It was shown that the stress distribution factor used for the calculation of elastic modulus from deflection testing is significantly influenced by the loading plate diameter. Moreover, the use of a harder rubber mat was found to be better, but no significant effect was observed for bonded rubber mat conditions.

Activities of the Vastus Lateralis and Vastus Medialis Oblique Muscles during Squats on Different Surfaces

[Purpose] The purpose of the present study was to examine the effects of squat exercises performed on different surfaces on the activity of the quadriceps femoris muscle in order to provide information on support surfaces for effective squat exercises. [Subjects and Method] Fourteen healthy subjects performed squat exercises for five seconds each on three different support surfaces: hard plates, foam, and rubber air discs. Their performance was measured using electromyography. As the subjects performed the squat exercises on each surface, data on the activity of the vastus medialis oblique and the vastus lateralis, and the vastus medials oblique/vastus lateralis ratio, were collected. [Results] The activity of the vastus medialis oblique and the vastus medialis oblique/vastus lateralis ratio were found to be statistically significantly higher on rubber air discs than when the squats were performed on hard plates or foam. [Conclusion] To activate the vastus medialis obilique, and to enhance the vastus medialis oblique/vastus lateralis ratio, unstable surfaces that are highly unstable should be selected.

Racial Innocence: Performing American Childhood from Slavery to Civil Rights by Robin Bernstein

Reviewed by: Racial Innocence: Performing American Childhood from Slavery to Civil Rights by Robin Bernstein Jayna Brown (bio) Bernstein, Robin. Racial Innocence: Performing American Childhood from Slavery to Civil Rights. New York: New York UP, 2011. Through an amazing curation of materials carefully and painstakingly gleaned from a number of archives, including collections at the American Antiquarian Society and the Harvard Theatre Collection, Robin Bernstein shows how the innocence of white childhood was imagined and enacted in relation to fictional versions of the black child, rendered in advertisements, collectibles, children’s books and toys, and especially dolls, from the antebellum era into the 1910s. Dolls and toys are “scriptive things,” Bernstein argues, “item[s] of material culture that prompt meaningful bodily behaviors” (Bernstein 8, 71). Violence against African Americans is the key “inscription” Bernstein traces through the performed relationships white children have with their black dolls. Child’s play with black effigies was most often scripted for acts of degradation and cruelty, and is crucial to understanding how racist violence against African Americans was naturalized. At the center of her argument is white girlhood, as embodied in the dyad Topsy and Little Eva from Harriet Beecher Stowe’s novel Uncle Tom’s Cabin and its aftermath in popular culture. [End Page 482] This dyad is embodied powerfully in the topsy-turvy doll, that inverts into either Eva or Topsy depending on which way you turn the skirts. As opposed to earlier versions of the child, as born into original sin until saved, the blessed and “tender angel” Eva embodies the shift to the idea of the child as born innocent and pure. Eva is an American trope, made possible through her performance of generous intimacy with the insensate picaninny Topsy. Not only childhood but slavery is made innocent through Eva’s touch, as Bernstein shows in the pictorial relationship between Eva and Uncle Tom found in illustrations to Stowe’s novel. A few years ago I was made cognizant of the durable, widespread ubiquity of the trope of Topsy and Little Eva. In an Ikea store in Southern California with my newlywed friend (a black woman) and her white mother-in-law, my friend left us alone for a moment. When she returned, her mother-in-law exclaimed, “Here comes Topsy now!” Tears and apologies ensued, but I will never forget how easy it was for the older woman to find that reference, lodged, as she told us, in memories from her girlhood in North Carolina. Bernstein’s book is an excellent study of material culture, carefully reading the politics of the manufacture of these toys in their historical context. For instance, Bernstein explains how soft dolls were developed not only for cuddling but to withstand abuse, which she argues is profoundly racialized and gendered. Many dolls in Bernstein’s study accompany storybooks, such as the Golliwog dolls, based on characters invented by Florence Upton, and Raggedy Ann dolls, which John Gruelle designed to accompany his children’s books. Bernstein explains how these dolls have deep roots in minstrelsy. Bernstein’s elucidation of the cruelty involved in the creation of toys and the narratives of storybooks, that supposedly represent the innocence of childhood, is arresting. But it is how white children played with the dolls I find most disturbing in the book. Out of the many examples of white girls and their interaction with their black dolls and figurines, a few will continue to haunt me. Bernstein relates the case of Frances Hodgson Burnett, who in her girlhood memoir The One I Knew Best of All: A Memory of the Mind of a Child reminisces about her relationship with a particular black doll, made of a hard rubber called “gutta percha,” that she named Topsy. According to Bernstein, the hard bodied material of the doll “script[ed] broadly violent play,” enacting the fantasy of black imperviousness to pain (Bernstein 71). In one instance, Burnett renamed the doll Uncle Tom and acted as the slave master Simon Legree, binding the doll to a candelabra and beating it, while “furious with insensate rage” (Bernstein 69). Bernstein explains, “Burnett’s act was one of many that installed childhood innocence as a powerful component...

Full-scale 저경도 납면진받침의 온도의존성에 대한 실험적 연구

Abstract Rubber laminated bearings with lead core are highly affected by changes in temperature because key materials which are rubber and lead have temperature dependencies. In this study, two full scale LRB(D800, S=5) are manufactured and temperature dependency tests on shear properties are accomplished. The shear properties at the 3rd cycle are used at -10℃, 0℃, 10℃,20℃, 30℃, 40℃ respectively. The double shear configuration, simultaneously testing two pieces, is applied for compression shear test in order to minimize the friction effects due to the test machine, described in ISO 22762-1:2010. Characteristic strength, post-yield stiffness, effective stiffness, equivalent damping ratio are estimated and presented coefficient due to the temperature changes. Keywords :lead rubber bearing, temperature dependency, low hardness rubber, nuclear power plants † Corresponding author: Tel: +82-41-620-3431; E-mail: parkjy@uet.co.krReceived November 9 2012; Revised November 28 2012;Accepted November 28 2012Ⓒ2012 by Computational Structural Engineering Institute of KoreaThis is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons. org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

The Country Store: In Search of Mercantiles and Memories in the Ozarks

[ILLUSTRATION OMITTED] There's nothing quite like going back home. If, like me, you're a child of the rural South, you'll know that feeling, see and smell and hear and feel that feeling. The smell of tilled earth or freshly cut hay, the crackle of a gravel road beneath hard rubber, that old whiff of red oak and varnish in the church house, low clouds of wood-stove smoke on winter mornings, jar flies on sultry summer days, lightning bugs and a Chuck-will's-widow in a dusky hollow. You can even taste it: well-water from a faucet, Momma's cornbread and pinto beans, cappuccino and a slice of Arrezzio's Chicago-style with black olives and banana peppers from the country store. Takes you back, doesn't it? Nothing reminds me of dear ol' Aunt Nellie quite like pizza, espresso, and frothing milk--except for maybe a Harley-Davidson do-rag, lemongrass soap, and a fifteen-minute bake in a tanning bed, all of which you can get at the country store, too. You know, back there next to the hoe handles and saw blades and pig shorts--the kind for feeding, not wearing. A couple of generations ago, a traveler in the rural South encountered a general mercantile every five miles or so. Most were simple establishments, combining the functions of filling stations, groceries, feed stores, hardware shops, and community centers under one roof. They were family-owned and operated, with the owners often occupying living quarters in back, upstairs, or in a house next door. Sometimes the country store was also home to the community post office, all the more reason for people to gather on the front porch or huddle around the potbellied stove inside. This country store of yesteryear no longer exists. Even in the most remote nooks and crannies of the South--Appalachia, the Ozarks, the Delta--the nostalgia seeker will come up short in the quest for mercantiles reminiscent of Lure and Abner's old Jot-em-Down Store, with its hand-cranked telephone, its cracker barrels and nail kegs, its bologna and produce hanging from the rafters, its fifty-pound sacks of flour and twenty-pound bags of sugar, its Bull of the Woods tobacco and Red Top snuff, its hardwood floors and creaking screen door and clanging wooden cash register. Yet, the essence of the country store, its immutable country storeness, has survived, even as the symbols by which it was once identified have faded into the past. In the face of a succession of challenges--parcel post and mail-order houses, automobiles and the good roads movement, dime stores and supermarkets and Walmart--the country store survives, albeit in scarcer quantities and with an evolution over time that has kept it relevant to its rural clientele. The survivors--and there are more of them than you might imagine--are models of adaptation. Country merchants no longer buy much of anything from their customers, no cream or eggs, apples, or hickory handles. They no longer furnish sharecroppers and small landowners in exchange for 10 percent per annum interest rates and liens on crops either. Instead, you will find in the Ozarks dozens of stores that serve their local customers in many of the same ways that their predecessors served rural communities generations ago, by providing feed and fertilizer, gasoline and farm diesel, tools and local gossip, groceries and tobacco products, overalls and work boots, benches and a warm stove. The country store has evolved to meet the changing needs of a rural clientele more likely to drive thirty miles to work in service jobs in the county seat than to spend all day plowing the back forty, gathering eggs, and milking cows. They also continue to provide a glimpse into life in the modern-day rural South, just as what remains of their predecessors, the yellowed photographs and musty ledgers and daybooks, provide an invaluable window into the region's past. As we are all susceptible to the pull of nostalgia, the country store's hallowed position in our collective memory seems secure. …