Choosing new ways to chew

No abstract availabl

Dynamic Evaluation of Forces During Mastication

A reproduction of the human masticatory system is presented here to evaluate mechanical properties of foods, relevant design elements of the simulator, and the overall practicality of the system. The model incorporates a cam-driven linkage system providing realistic motion of the mandible, with reaction forces measured by strain gages on two axes to record real time changes in food structure. The experiment demonstrates that the construction of a mastication simulator is feasible and allows texture profiling and discrimination between similar foods

DEVELOPMENT OF A SOFT PNEUMATIC ACTUATOR FOR MODULAR ROBOTIC MECHANISMS

Soft robotics is a widely and rapidly growing field of research today. Soft pneumatic actuators, as a fundamental element in soft robotics, have gained huge popularity and are being employed for the development of soft robots. During the last decade, a variety of hyper-elastic robotic systems have been realized. As the name suggests, such robots are made up of soft materials, and do not have any underlying rigid mechanical structure. These robots are actuated employing various methods like pneumatic, electroactive, jamming etc. Generally, in order to achieve a desired mechanical response to produce required actuation or manipulation, two or more materials having different stiffness are utilized to develop a soft robot. However, this method introduces complications in the fabrication process as well as in further design flexibility and modifications. The current work presents a design scheme of a soft robotic actuator adapting an easier fabrication approach, which is economical and environment friendly as well. The purpose is the realization of a soft pneumatic actuator having functional ability to produce effective actuation, and which is further employable to develop modular and scalable mechanisms. That infers to scrutinize the profile and orientation of the internal actuation cavity and the outer shape of viii the actuator. Utilization of a single material for this actuator has been considered to make this design scheme convenient. A commercial silicone rubber was selected which served for an economical process both in terms of the cost as well as its accommodating fabrication process through molding. In order to obtain the material behavior, \u2018Ansys Workbench 17.1 R \u2019 has been used. Cubic outline for the actuator aided towards the realization of a body shape which can easily be engaged for the development of modular mechanisms employing multiple units. This outer body shape further facilitates to achieve the stability and portability of the actuator. The soft actuator has been named \u2018Soft Cubic Module\u2019 based on its external cubic shape. For the internal actuation cavity design, various shapes, such as spherical, elliptical and cylindrical, were examined considering their different sizes and orientations within the cubic module. These internal cavities were simulated in order to achieve single degree of freedom actuation. That means, only one face of the cube is principally required to produce effective deformation. \u2018Creo Perametric 3.0 M 130\u2019 has been used to design the model and to evaluate the performance of actuation cavities in terms of effective deformation and the resulting von-mises stress. Out of the simulated profiles, cylindrical cavity with desired outcomes has been further considered to design the soft actuator. \u2018Ansys Workbench 17.1 R \u2019 environment was further used to assess the performance of cylindrical actuation cavity. Evaluation in two different simulation environments helped to validate the initially achieved results. The developed soft cubic actuator was then employed to develop different mechanisms in a single unit configuration as well as multi-unit robotic system developments. This design scheme is considered as the first tool to investigate its capacity to perform certain given tasks in various configurations. Alongside its application as a single unit gripper and a two unit bio-mimetic crawling mechanism, this soft actuator has been employed to realize a four degree ix of freedom robotic mechanism. The formation of this primitive soft robotic four axis mechanism is being further considered to develop an equivalent mechanism similar to the well known Stewart platform, with advantages of compactness, simpler kinematics design, easier control, and lesser cost. Overall, the accomplished results indicate that the design scheme of Soft Cubic Module is helpful in realizing a simple and cost-effective soft pneumatic actuator which is modular and scalable. Another favourable point of this scheme is the use of a single material with convenient fabrication and handling

Investigating the Design and Manufacture of PneuNet Actuators as a Prosthetic Tongue for Mimicking Human Deglutition

The number of Total Glossectomy cases in the United States is seeing an increasing trend as per the Nationwide Inpatient Sample Database. Patients, who have undergone such aggressive surgical procedures, have extensive limitations performing basic oral functions such as swallowing (deglutition), eating and speaking. Current rehabilitation prostheses do little in restoring the functionality of the original tongue. This is true especially in deglutition, which is necessary to transfer a bolus to the esophagus. Such patients need advanced prosthetic devices and through this research, investigations into potential solutions for prosthetic tongues to aid in deglutition were carried out. The process began with an extensive literature review that provided tongue position, motion, and pressure data during the swallowing stages. Several potential designs were considered such as using linkages and pneumatic networks (PneuNets). Based on a decision matrix, PneuNets were adopted as the foundational basis for generating prosthetic designs. Several prototypes were fabricated using Fused Filament Disposition for mold development and silicone Eco-flex 00-30 for actuator development. Each iteration involved tackling several design and manufacturing challenges especially when scaling these actuators from an initial experiment to an anatomical shape and size of a human tongue. A tongue of dimensions 1.8 inches wide, 2.4 inches long and 0.24 inches thick was developed. The PneuNet actuator was powered by a pneumatic system and kinematic data was collected using a tracking software. The data gathered provided validation comparisons between position trends exhibited in the literature. Theoretical deflection models were generated for analyzing the deflection of the front, middle and back sections of the tongue prototype. Details from literature review, design iterations, simulations, validation processes, research challenges and conclusions will be discussed in depth

Tongue Pressure - A Key Limiting Aspect in Bolus Swallowing

Food oral processing is very basic activity of human life, providing individuals with pleasure, enjoyment and serving their needs for social interaction. Dysphagia describes a disorder affecting the safety and/or efficiency of swallowing. To manage this reduced ability, dysphagic individuals are often prescribed a diet having specific ranges of mechanical properties. As a result, a number of sectors such as food, pharmaceutical and health care industries are eagerly searching for fundamental knowledge in order to design food for vulnerable population. This thesis addresses this gap and aims to investigate the relationship between the mechanical properties of bolus swallowing (e.g. rheology, bolus manipulations, perceived ease / difficult of initiation swallowing and perceived bolus flow behaviour) along with oral pressures (i.e. generated by the tongue) recorded in healthy subjects. This area of oral processing is researched mostly from a clinical point of view and thus knowledge in oral processing from sensory view point is currently limited as shown in the literature review. In this study, some of existing clinical researches were extended using relevant techniques (such as maximum isometric tongue pressure, oral volume and oral residence time). Findings from this thesis demonstrated a strong correlation between sensory perception of bolus (e.g. ease / difficult of swallowing, ease of break-swallow, bolus flow) and subjective measurement of tongue pressure in context of ready-to-swallow food bolus with different rheological properties. Further experiments were conducted to mechanically characterise a range of viscoelastic and pastry food systems and measure the intra-oral pressures applied when breaking these foods. Data analysis showed that a positive correlation existed between tongue strength and oral food handling. From our results, we can conclude that individual’s capacity in tongue pressure generation needs to exceed a certain limit in order to perceive ease in swallowing bolus and also to perceive a bolus flow behaviour. However, such correlation was not seen for individuals with reduced capability in generating MITP. These results support the aim that both the oral physiological conditions (MITP) and the rheological properties of the food (bolus) are important factors that influence the bolus manipulations and comfortable oral handling as well as perceived ease of initiating bolus flow

Theoretical Puncture Mechanics of Soft Compressible Solids

Accurate prediction of the force required to puncture a soft material is critical in many fields like medical technology, food processing, and manufacturing. However, such a prediction strongly depends on our understanding of the complex nonlinear behavior of the material subject to deep indentation and complex failure mechanisms. Only recently we developed theories capable of correlating puncture force with material properties and needle geometry. However, such models are based on simplifications that seldom limit their applicability to real cases. One common assumption is the incompressibility of the cut material, albeit no material is truly incompressible. In this paper we propose a simple model that accounts for linearly elastic compressibility, and its interplay with toughness, stiffness, and elastic strain-stiffening. Confirming previous theories and experiments, materials having high-toughness and low-modulus exhibit the highest puncture resistance at a given needle radius. Surprisingly, in these conditions, we observe that incompressible materials exhibit the lowest puncture resistance, where volumetric compressibility can create an additional (strain) energy barrier to puncture. Our model provides a valuable tool to assess the puncture resistance of soft compressible materials and suggests new design strategies for sharp needles and puncture-resistant materials

Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

Recent Advances and Current Developments in Tissue Scaffolding

A bio-scaffold can be broadly termed as a structure used to substitute an organ either permanently or temporarily to restore functionality. The material that can be used varies with the application intended. Tissue engineering is one such application demanding certain requirements to be met before it is applied. One of the applications in tissue engineering is the tissue scaffold, which provides either a permanent or temporary support to the damaged tissues/organ until the functionalities are restored. A biomaterial can exhibit specific interactions with cells that will lead to stereotyped responses. The use of a particular material and morphology depends on various factors such as osteoinduction, osteoconduction, angiogenesis, growth rates of cells and degradation rate of the material in case of temporary scaffolds, etc. The current work reviews the state of art in tissue scaffolds and focuses on permanent scaffold materials and applications with a brief overview of temporary scaffold materials and their disadvantages

Modelling of chewing and aroma release during oral processing : model development, model validation and comprehensive examples for food design : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemical and Bioprocess Engineering, Massey University, Palmerston North, New Zealand

These Figures were removed for copyright reasons: 2-1 (=Lucas et al., 2002 Fig 1), 2-2 (=Hiiemae, 2004 Fig 1), 2-4 (=Mosca & Chen, 2017 Graphical abstract), 2-6 (=Zhang et al., 2019, Fig 1) and 2-11 (=Doyenette et al., 2014 Fig 1).Chewing is complex because of its sub-processes and interactions, and inter-individual differences between people. The development of mechanistic models can be a tool to explore these aspects and can lead to the development of foods with controlled digestion outcomes and improved sensory appeal. A mechanistic chewing model was developed based on selection and breakage processes and implemented using a discretised population balance to predict the changes in bolus particle size distribution during chewing. The model was successfully implemented on peanuts, which gave confidence for its implementation to cooked white rice, which is an aromatic food system and has strong correlations with in vitro digestion. The relationship between panellists physiological, chewing and aroma release parameters during mastication of white rice were investigated in vivo to provide insights for model development. The findings showed that the dynamic behaviour of aroma release of all five subjects followed a similar trend with the breakdown pathways where subjects with smaller particles size in their bolus had higher aroma release. The study paved the first step in understanding the role of chewing on aroma release of cooked white rice and provided a range of oral processing behaviours for model validation. A coupled chewing and aroma release model was developed and validated against experimental data. Adjusting the input parameters from the coupled model showed that the portion size, initial concentration of the studied aroma compound, initial liquid volume and the rice pasted fraction were the most sensitive product-related parameters. The oral cavity volume, pharynx volume, nasal cavity volume and the breathing frequency were the most sensitive physiological parameters. The physico-chemical parameter which had the most significant effect was the mass transfer coefficient in the saliva phase. Examples were also given to show the difference in aroma release when aroma compounds of varying partition coefficients were used. The work from this thesis constitutes the first step in the application of mechanistic chewing models as a tool for food design. The next step will be to expand these models to a wider range of food systems and to a larger number of individuals to improve the model reliability