Shoe Soles Research Articles

Optimization of the Rubber Formulation for Footwear Applications from the Response Surface Method.

Impact force remains the primary cause of foot injury and general discomfort with regard to footwear. The footwear industry traditionally relies on modified elastomers (including natural rubber) whose properties can be physically adjusted by varying the constituents in the rubber formulations. This work aims to investigate the effect of filler/plasticizer fractions on shock attenuation of natural rubber soles. The statistical response surface method (RSM) was used to optimize the loading of natural rubber, fillers (carbon black and china clay) and a plasticizer (paraffinic oil). A novel predictive equation addressing the effects of additives on the physical and mechanical properties of the shoe sole was successfully created using the RSM. Our results demonstrate how the concentrations of these components regulate final properties, such as impact force absorption and hardness, in the commercial manufacture of shoe soles. While a higher loading level of plasticizer promotes reductions in hardness and impact force, as well as energy dissipation, in these modified elastomers, these properties were improved by increasing the filler content.

Anesthesiologist behavior and anesthesia machine use in the operating room during the COVID-19 pandemic: awareness and changes to cope with the risk of infection transmission.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease [coronavirus disease 2019 (COVID-19) infection] first appeared in December 2019 in China and is now spreading worldwide. Because SARS-CoV-2 can be transmitted via aerosols and surface contaminations of the environment, appropriate use of anesthesia machines and appropriate behavior in the operation room (OR) are required specifically in relation to this disease. The use of high-performance hydrophobic filters with a high rate of virus rejection is recommended as the type of viral filter, and surgical team behaviors that result in aerosol splashes should be avoided. Appropriate hand hygiene by the anesthesiologist is crucial to prevent unexpected environmental contamination. When the anesthesia machine is used instead of an intensive care unit ventilator, it is important to keep the fresh gas flow at least equal to the minute ventilation to prevent excessive humidity in the circuit and to monitor condensation in the circuit and inspiratory carbon dioxide pressure. In addition, both the surgical smoke inherent in thermal tissue destruction and the surgical team’s shoe soles may be factors for the presence of SARS-CoV-2 in the operating room. Ensuring social distancing—even with a mask in the OR—may be beneficial because healthcare providers may be asymptomatic carriers. After the acute crisis period of COVID-19, the number of cases of essential but nonurgent surgeries for waiting patients is likely to increase; therefore, optimization of OR scheduling will be an important topic. Anesthesiologists will benefit from new standard practices focusing on the prevention of COVID-19 infection.

Energy Harvesting Using Shoe Embedded with Piezoelectric Material

We have investigated the effect of the position and dimension of piezoelectric buzzers embedded in shoe soles on energy harvesting. The force and pressure generated by different types of shoes and heels were measured using plantar measurement systems. A Kistler force plate and zebris force distribution measurement provided precise values and locations of the force and pressure exerted by the foot on the sole. The position and area of buzzers inside the sole of the shoes resulted in a significant increase in electrical outputs. A maximum open-circuit voltage of 38 V, short circuit current of 33 μA, and harvested energy of 296.8 μJ cm−3 were found across a 100-μf capacitor for a wedge-heeled shoe. The open-circuit voltage in the wedge-heel type of shoe improved by more than five times when the pressure is changed from the heel to the toe and area of the buzzer is increased. Similarly, the energy stored across a 100-μF capacitor also improved by five times for the same shoe. Furthermore, the short circuit current improved by three times when the shoe was changed from a wedge heel to a block heel. The results indicate that this technique can be used to power wearable electronics and sensors.

Effects of Porosity and SEBS Fraction on Dry Sliding Friction of EVA Foams for Sports Shoe Sole Applications

Ethylene vinyl acetate (EVA) foam is sometimes used in the outer soles of sport shoes. To improve the slip resistance of EVA foam, this study investigated the effects of porosity and the fraction of styrene–ethylene–butadiene–styrene (SEBS) on the dry sliding friction behavior of EVA foams. Sliding friction tests were performed against a pin specimen with a semicylindrical tip, which was covered with (rough surface) or without abrasive paper (smooth surface). The results revealed that the friction coefficient of the EVA foam increased with porosity when slid against a smooth surface, whereas its friction coefficient increased with porosity and SEBS fraction when slid against a rough surface. The results of this investigation provide insight into how to increase the dry sliding friction of resin foam against smooth and rough surfaces, which will also contribute to improving the slip resistance of shoe soles made from resin foam.

A Bayesian hierarchical model for evaluating forensic footwear evidence

When a latent shoeprint is discovered at a crime scene, forensic analysts inspect it for distinctive patterns of wear such as scratches and holes (known as accidentals) on the source shoe’s sole. If its accidentals correspond to those of a suspect’s shoe, the print can be used as forensic evidence to place the suspect at the crime scene. The strength of this evidence depends on the random match probability—the chance that a shoe chosen at random would match the crime scene print’s accidentals. Evaluating random match probabilities requires an accurate model for the spatial distribution of accidentals on shoe soles. A recent report by the President’s Council of Advisors in Science and Technology criticized existing models in the literature, calling for new empirically validated techniques. We respond to this request with a new spatial point process model (code and synthetic data is available as Supplementary Material) for accidental locations, developed within a hierarchical Bayesian framework. We treat the tread pattern of each shoe as a covariate, allowing us to pool information across large heterogeneous databases of shoes. Existing models ignore this information; our results show that including it leads to significantly better model fit. We demonstrate this by fitting our model to one such database.

Preparation and Performance Test of PEFB Reinforced Box Waste Coated Superhydrophobic Coating for Shoe Sole Application

Preparation and Performance Test of PEFB Reinforced Box Waste Coated Superhydrophobic Coating for Shoe Sole Application

A Survey of the Thickness of the Shoe Sole among Junior High School Students in Greater Jakarta for Shoe Correction in Seat Height-Popliteal Height Equation

This paper aimed to present a survey result of the thickness of the shoe sole among junior high school students in Greater Jakarta, Indonesia. A number of 160 samples of the shoe wearing by junior high school students (85 boys and 65 girls) from Grade 7-Grade 9 was measured. The thickness of the sole of the shoe wearing by them were measured. The results were presented in mean and SD for each grade and gender. T-test results showed that no significant differences were found for thickness of the sole of the shoe wearing by boys and girls within the same grade. Anova test results also revealed that no significant differences were found for thickness of the sole of the shoe among boys in Grade 7-9 (F=0.54, p=0.58) and girls (F=1.06, p=0.35). Findings in this study revealed that a 20mm shoe correction, as often used by many researchers, which is added to the popliteal height to dimension the seat height (SH) is appropriate to be used for population under study. The results of this study provided sufficient justification for the use of a 2 cm shoe correction (SC) in addition to popliteal height when determining seat height of the chair.

Effect of the Porosity Distribution on Dry Sliding Friction and Wear of Cross-Linked Ethylene Vinyl Acetate Foams With a Skin Layer

Shoes are an essential item in daily life to prevent slip-and-fall accidents and to improve performance in human activities such as walking, running, and jumping. These effects are supported by the friction between the outer shoe soles and the floor. In designing the friction of the outer sole, the wear resistance must be also considered to maintain slip resistance and provide a longer shoe lifetime. Rubber is the most popular material for the outer sole in shoe design, but it is also common to use a cross-linked resin foam on the outer sole to reduce the weight and improve the slip resistance. Ethylene vinyl acetate (EVA) is a popular material for the shoe foam material. In general, cross-linked EVA foam has a non-uniform porosity distribution, and especially near the surface in the low-porosity region called the skin layer. Here, it is considered that the friction and wear behaviors of cross-linked EVA foams can be changed via the skin layer, but the influence of the porosity distribution on the friction and wear behaviors has not been clarified. Using cross-linked EVA foams with a skin layer, this study focused on the foam friction and wear behaviors on a rough surface as a function of the porosity distribution. The friction and wear behaviors were found to depend on the wear surface porosity, which increased with wear progress. In addition, the friction coefficient exhibited a positive and negative correlation with the porosity of the wear surface and the normal force, respectively, while the specific wear rate increased with both parameters. These results are particularly meaningful for designing shoe materials.

Composites of Styrene-Butadiene Block-Copolymer Reinforced with Waste Printed Circuit Boards (WPCB)

In recent years, the rapid development of electronic equipment led to millions of tons of waste printed circuit boards (WPCB) generated in the entire world rising important concerns regarding its recycling. Besides the metals recovery, intensively studied, the reuse of the nonmetals is especially difficult. In this study, the non-metallic fraction from the waste of printed circuit boards is used as reinforcing filler of a styrene-butadiene block-copolymer. The composites were characterized by mechanical and dynamo-mechanical analysis and thermo-gravimetry. The study aimed the reintroduction into the economic circuit of WPCB as composites suitable for the production of shoe soles injected directly on the footwear faces and as bitumen modifiers for road coverings.

A Smart Manufacturing Solution for Multi-Axis Dispenser Motion Planning in Mixed Production of Shoe Soles

Mixed production is a practical solution to realize the idea of mass product customization. The production system needs to adapt to raw materials of product variants appearing in the production line, and thus to properly complete the manufacturing task. Such system autonomy is a core competence in smart manufacturing. This paper presents a smart manufacturing solution for shoe sole gluing in mixed production environment. The solution automatically guides a 5-axis CNC dispensing machine to perform the gluing task of a sole randomly placed on the worktable without use of fixturing. A single RGB-D camera is used to capture the color and depth data of the work environment. A two-stage algorithm is implemented to provide the intelligence required by the solution using the captured data as input. The LINEMOD method first determines a rough pose from training data of all shoe soles at pre-defined orientations. A trimmed interactive closest point (ICP) method then refines the pose using the rough one as the initial solution. Pre-determined working paths are transformed into the correct location around the sole with the refined pose. The corresponding motion commands drive the dispenser controller to complete the gluing task without collision. Test results of real shoe soles validate the effectiveness of the proposed solution. This work contributes to smart manufacturing in the shoe making industry, which has been less studied in the past.

A vision guided robotic system for flexible gluing process in the footwear industry

Abstract This paper presents a novel gluing machine comprising a Cartesian robot and a vision system. The vision system enables the location and reconstruction of the shape of objects to be glued; the detected information is then used to plan the trajectory of the robot whose end-effector is a glue gun and to move the robot with an error suitable to industrial gluing operations. A calibration procedure that enables transforming coordinates between the robot frame and the vision system frame is described. The calibration considers several mechanical inaccuracies and its effectiveness was evaluated using error maps. In particular, the paper examines objects to be glued along their edges, as frequently occurs for fabrics, leathers, and shoe soles. For this, two procedures to plan the trajectories of the robot are proposed: the first is for objects that can be treated as flat 2D objects, that is, their height variation is negligible; the second procedure is for 3D objects, that is, those with significant height variation. Several applicative examples are reported to highlight the flexibility of the gluing process.

Влияние гидросиликата магния на свойства подошвенной резины

The properties of rubber products are determined by the nature and content of caoutchoucs, vulcanizing systems and other ingredients. Among them, fillers play an important role. The most common fillers are carbon black and silicas. Recently, in connection with the increasing operational requirements for rubber products, additives of special fillers began to be introduced into rubber mixtures. Among them, silicates are of practical interest, the use of which allows not only to reduce the cost, but also to give qualitatively new useful physical and mechanical properties to rubbers. Improving the physical and mechanical properties of rubbers directly depends on the particle size of the fillers. Fillers with a smaller particle size have a larger surface area and have a significant effect on the physical and mechanical properties of rubbers. The highly developed surface of powdered magnesium hydrosilicate suggests its use as a filler for rubber compounds. In this regard, it is of interest to study the effect of magnesium hydrosilicate on the properties of rubbers. This article explored the possibility of using magnesium hydrosilicate in plantar rubber based on a combination of nitrile butadiene SKN-4055, methyl styrene butadiene SKMS-30ARK and isoprene SKI-3 caoutchoucs. The rheometric properties were investigated for the rubber mixture, and the physical and mechanical properties, hardness, resistance to thermal aging and the action of aggressive media were determined for vulcanizates. As a result of the studies, it was found that the best rheometric, physico-mechanical and operational properties are possessed by the vulcanizate of the rubber compound, in which the silicon-acid filler of rossil 175 was partially replaced by magnesium hydrosilicate. This rubber can be used in the production of oil and petrol resistant soles of rubber shoes.

THERMOGRAPHY AT MILLIMETRE WAVELENGTHS FOR SECURITY INSPECTION OF FOOTWEAR

© 2020, Electromagnetics Academy. All rights reserved. Millimetre-wave thermography is used to image through the soles of shoes as proof of principle study into the application of such an approach for security inspection. Current airport security screening practice necessitates the removal of shoes prior to x-ray screening for potential threats or other concealments, for example explosive or explosive precursor materials; narcotic substances or small weapons. The authors demonstrate that thermography at ~ 250 GHz is able to reveal a variety of objects concealed within the soles of typical shoes, and that such an approach might be applied to rapidly screen passengers without necessitating the removal of their footwear.

Characterisation of Shoe Soling Material Prepared by using Rubber and Leather Solid Waste

The ultimate aim of this research is to develop footwear soling materials from solid waste generated from leather industry. The Chrome shaving from the leather sector is used as a solid waste in this study. Styrene butadiene, Nitryl, Ethylene propylene monomer (EPDM) and Isoprene elastomers were used for this research. The rubber and chrome shavings mixes were prepared by using industrial two roll mill. Various propositions of rubbers, chrome shavings and nano fillers were characterised in this research. The developed soling materials were tested for physical testing like hardness, abrasion resistance, tensile strength, density and elongation at break and compared with compared with commercially available soling material. In this research four different experiments has been conducted among the four experiments the soling material prepared using a isoprene rubber-70 Phr and EPDM rubber - 30Phr with chrome shavings -50 Phr and KLN(Silica based) nano fillers- 7 Phr meets the required parameters of commercial soling material. Hence, it is concluded that chrome shaving wastes from tannery in soling material preparation is one of the best remedy for the environmental issues.

Management of spiral diaphyseal fractures of the fifth metatarsal: A case series and a review of literature

IntroductionSpiral diaphyseal fractures of the fifth metatarsal can present with significant displacement. It is considered that non-operative management is sufficient in most cases but there is no clear consensus as to what this may be. This study reports the functional outcome of this injury in a small patient cohort and is the first study to report on outcomes of different non-operative measures. Material and methodsThis is a retrospective study of 33 consecutive patients presenting to a central London teaching hospital who were managed by a variety of treatment modalities depending on surgeon preference which included a boot or a rigid sole shoe. Demographic data was obtained and time to pain free walking and return to normal footwear was recorded. The patients were asked how restrictive the injury was on a Likert scale (1–5). The average final follow up was 12 months. ResultsAll fractures were managed conservatively with excellent functional outcomes. Those patients managed in a shoe had a statistically significant shorter average time to return to pain free walking (4.6 vs 8.4 weeks, p=0.027) and average time to return to normal footwear (6 vs 7.3 weeks, p=0.044) in comparison to a boot. Patients managed in a shoe reported the injury was less restrictive in comparison to patients managed in a boot (p=0.0002). The average time to evidence of bony union was 8.3 weeks. There were 3 delayed unions. ConclusionAll patient in this series were treated without surgery regardless of the degree of displacement. Conservative management of this fracture in a rigid sole shoe resulted in better outcomes and was reported to be less restrictive by the patients in comparison to a boot. On this basis, non-surgical management of these injuries is recommended in a shoe, full weight bearing with early range of movement of the ankle.

Dataset of Digitized RACs and Their Rarity Score Analysis for Strengthening Shoeprint Evidence.

In recent years, there is a growing demand to fortify the scientific basis of forensic methodology. During 2016, the President's Council of Advisors on Science and Technology (PCAST) published a report that states there are no appropriate empirical studies that support the foundational validity of footwear analysis to associate shoeprints with particular shoes based on specific identifying marks, which is a basic scientific demand from the field. Furthermore, meaningful databases that can support such studies do not exist. Without such databases, statistical presentation of the comparison results cannot be fulfilled either. In this study, a database of over 13,000 randomly acquired characteristics (RACs) such as scratches, nicks, tears, and holes, as they appear on shoe sole test impressions, from nearly 400 shoe soles was collected semi-automatically. The location, orientation, and the contour of each RAC were determined for all the RACs on each test impression. The statistical algorithm Statistic Evaluation of Shoeprint Accidentals (SESA) was developed to calculate a score for finding another feature similar to a particular scanned and digitized RAC in the same shape, location, and orientation as the examined one. A correlation was found between the results of SESA and the results of real casework, strengthening our belief in the ability of SESA to assist the expert in reaching a conclusion while performing casework. The score received at the end of the process serves the expert as a guiding number, allowing more objective and accurate results and conclusions.

The Effect of Material Characteristic of Shoe Soles during Long Duration Running

Long duration running has been associated with musculoskeletal injuries such as patellofemoral pain syndrome and knee osteoarthritis. This study was designed to investigate the effects of two different shoe insoles on kinematic and kinetic performance during long duration running. In total 15 subjects (7 males and 8 females) were recruited to perform 15 minutes continuous running on the treadmill in 3 different shoe insole conditions: (i) no insole; (ii) Ethyl Vinyl Acetate (EVA) insole and (iii) Polyurethane (PU) insole. The result revealed a significant increase in maximum vertical ground reaction force (VGRF) with the PU insole compare with the no insole and EVA insole conditions (p<0.05). There is no difference between conditions in kinematic variables: step length, stride length and cadence (p>0.05).

The Effect of Piezoelectric Shape on Energy Harvesting Shoes

Piezoelectric elements are commonly installed in shoe sole to make use of the piezoelectric effect due to the vibration generated by the human motion. Piezoelectric shoe is a great device that can be used to harvest energy and can be improved by adding more piezoelectric elements and providing storage to store the harvested energy. However, not many researchers focus on the analyzation of piezoelectric elements’ shape that may affect the efficiency of energy harvesting. In this paper, piezoelectric energy harvesting shoes are designed with piezoelectric elements installed inside the soles of the shoes, thereby gaining mechanical energy from user while walking and running. The mechanical energy was applied to the piezoelectric elements and converted into electrical energy. Bridge rectifier was used to convert the AC voltage output into DC voltage. The project focused on analyzation of the efficiency between round and square shaped piezoelectric elements. Different shape of the piezoelectric element produced different amount of output voltage. Square shaped piezoelectric tended to produce lesser output voltage than the round piezoelectric element. A round piezoelectric with diameter of 4.5cm produced mean output voltage up to 11.56V and square piezoelectric with size of 4.5cm x 4.5cm produced 6.12V. However, this all depended on how much pressure that was applied onto the piezoelectric elements.

Features of the formation compositions for shoe soles

Features of the formation compositions for shoe soles

Composites of Styrene-butadiene Block-copolymers Reinforced with WEEE Polystyrene Fraction

The high global production of electric and electronic equipment increases in the same manner the amount of the waste that needs to be recycled. Special attention is given to the plastics recycling from the waste in addition to the metals recovery that brings economic advantages. Considering that the plastic amount contains about 80% polystyrene polymers, the paper presents a recycling study of this fraction as reinforcing agent for a styrene-butadiene block copolymer. In order to reduce the melt viscosity, some of the composites were extended with paraffin-naphthenic �heavy white oil�. The blends were characterized by mechanical testing, thermal and dynamo-mechanical analysis. Based on the resulted properties, it can be concluded that the extended and reinforced composites can be used as material for shoe soles.