This PDF file contains the front matter associated with SPIE Proceedings Volume 9797 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Studies on some species of insects have shown them to use the polarization pattern cast by the moon in the night sky to control heading. Additional heading cues are of value to autonomous systems, since the earth’s magnetic field is not uniform, often not available and is substantially modified by local phenomena. In addition to the required low-light sensitivity of a night time polarization compass, additional complexities caused by the relative intensity of terrestrial sources must be overcome. We will show that the end result will tend to be a less reliable compass than the equivalent day time polarization device.

At night, our visual capacities are severely reduced, with a complete loss in our ability to see colour and a dramatic loss in our ability to see fine spatial and temporal details. This is not the case for many nocturnal animals, notably insects. Our recent work, particularly on fast-flying moths and bees and on ball-rolling dung beetles, has shown that nocturnal animals are able to distinguish colours, to detect faint movements, to learn visual landmarks, to orient to the faint pattern of polarised light produced by the moon and to navigate using the stars. These impressive visual abilities are the result of exquisitely adapted eyes and visual systems, the product of millions of years of evolution. Nocturnal animals typically have highly sensitive eye designs and visual neural circuitry that is optimised for extracting reliable information from dim and noisy visual images. Even though we are only at the threshold of understanding the neural mechanisms responsible for reliable nocturnal vision, growing evidence suggests that the neural summation of photons in space and time is critically important: even though vision in dim light becomes necessarily coarser and slower, it also becomes significantly more reliable. We explored the benefits of spatiotemporal summation by creating a computer algorithm that mimicked nocturnal visual processing strategies. This algorithm dramatically increased the reliability of video collected in dim light, including the preservation of colour, strengthening evidence that summation strategies are essential for nocturnal vision.

Chameleonization occurs when a self-learning autonomous mobile system’s (SLAMR) active vision scans the surface of which it is perched causing the exoskeleton to changes colors exhibiting a chameleon effect. Intelligent agents having the ability to adapt to their environment and exhibit key survivability characteristics of its environments would largely be due in part to the use of active vision. Active vision would allow the intelligent agent to scan its environment and adapt as needed in order to avoid detection. The SLAMR system would have an exoskeleton, which would change, based on the surface it was perched on; this is known as the “chameleon effect.” Not in the common sense of the term, but from the techno-bio inspired meaning as addressed in our previous paper. Active vision, utilizing stereoscopic color sensing functionality would enable the intelligent agent to scan an object within its close proximity, determine the color scheme, and match it; allowing the agent to blend with its environment. Through the use of its’ optical capabilities, the SLAMR system would be able to further determine its position, taking into account spatial and temporal correlation and spatial frequency content of neighboring structures further ensuring successful background blending. The complex visual tasks of identifying objects, using edge detection, image filtering, and feature extraction are essential for an intelligent agent to gain additional knowledge about its environmental surroundings.

The butterfly proboscis is a unique, naturally engineered device for acquiring liquid food, which also minimizes concerns for viscosity and stickiness of the fluids. With a few examples, we emphasize the importance of the scale-form functionality triangle of this feeding device and the coupling through capillarity.

This paper furthers the application of chemotaxis to small-scale robots by simulating a system that localizes a chemical source in a dynamic fluid environment. This type of system responds to a chemical stimulus by mimicking, for example, the way that E. Coli bacteria move toward attractants (nutrients) and away from repellents. E. Coli use the intracellular signaling pathway to process the temporal change in the chemical concentration to determine if the cells should run or tumble. Previous work has shown that this process can be simulated with robots and used to localize chemical sources based upon a fixed nutrient gradient. Our work furthers this study by simulating the injection of an effluent of chemical at a specified location in an environment and uses computational fluid dynamics to model the interactions of the robot with the fluid while performing chemotaxis. The interactions between the chemical and fluid are also modelled with the advection diffusion equation to determine the concentration gradient. This method allows us to compute, over a lattice, the chemical concentration at all points and feed these results into an existing E. Coli controller for the robot, which results in the robot executing a tumble or a run according to a probabilistic formula. By simulating the robot in this complex environment, our work facilitates refinement of the chemotaxis controller while proving the ability of chemotactic robots to localize specific chemicals in environments that more closely resemble those encountered in the wide-ranging types of locations in which this robotic system might be deployed.

This paper demonstrates the efficacy of implementing ultrasonic manipulation within a modified form of stereolithographic 3D printing to form complex microstructures in printed components. Currently 3D printed components are limited both in terms of structural performance and specialised functionality. This study aims to demonstrate a novel method for 3D printing composite materials, by arranging microparticles suspended within a photocurable resin. The resin is selectively cured by a 3-axis gantry-mounted 405nm laser. Ultrasonic forces are used to arrange the microfibres into predetermined patterns within the resin, with unidirectional microfibre alignment and a hexagonal lattice structure demonstrated. An example of dynamic microstructure variation within a single print layer is also presented.

X-ray imaging in the absorption contrast mode is an established method of visualising calcified tissues such as bone and teeth. Physically soft tissues such as brain or muscle are often imaged using magnetic resonance imaging (MRI). However, the spatial resolution of MRI is insufficient for identifying individual biological cells within three-dimensional tissue. X-ray grating interferometry (XGI) has advantages for the investigation of soft tissues or the simultaneous three-dimensional visualisation of soft and hard tissues. Since laboratory microtomography (μCT) systems have better accessibility than tomography set-ups at synchrotron radiation facilities, a great deal of effort has been invested in optimising XGI set-ups for conventional μCT systems. In this conference proceeding, we present how a two-grating interferometer is incorporated into a commercially available nanotom m (GE Sensing and Inspection Technologies GmbH) μCT system to extend its capabilities toward phase contrast. We intend to demonstrate superior contrast in spiders (Hogna radiata (Fam. Lycosidae) and Xysticus erraticus (Fam. Thomisidae)), as well as the simultaneous visualisation of hard and soft tissues. XGI is an imaging modality that provides quantitative data, and visualisation is an important part of biomimetics; consequently, hard X-ray imaging provides a sound basis for bioinspiration, bioreplication and biomimetics and allows for the quantitative comparison of biofabricated products with their natural counterparts.

The coupling between structural support and protection makes biological systems an important source of inspiration for the development of advanced smart composite structures. In particular, some particular material configurations can be implemented into traditional composites in order to improve their impact resistance and the out-of-plane properties, which represents one of the major weakness of commercial carbon fibres reinforced polymers (CFRP) structures. Based on this premise, a three-dimensional twisted arrangement shown in a vast multitude of biological systems (such as the armoured cuticles of Scarabei, the scales of Arapaima Gigas and the smashing club of Odontodactylus Scyllarus) has been replicated to develop an improved structural material characterised by a high level of in-plane isotropy and a higher interfacial strength generated by the smooth stiffness transition between each layer of fibrils. Indeed, due to their intrinsic layered nature, interlaminar stresses are one of the major causes of failure of traditional CFRP and are generated by the mismatch of the elastic properties between plies in a traditional laminate. Since the energy required to open a crack or a delamination between two adjacent plies is due to the difference between their orientations, the gradual angle variation obtained by mimicking the Bouligand Structures could improve energy absorption and the residual properties of carbon laminates when they are subjected to low velocity impact event. Two different bioinspired laminates were manufactured following a double helicoidal approach and a rotational one and were subjected to a complete test campaign including low velocity impact loading and compared to a traditional quasi-isotropic panel. Fractography analysis via X-Ray tomography was used to understand the mechanical behaviour of the different laminates and the residual properties were evaluated via Compression After Impact (CAI) tests. Results confirmed that the biological twisted structures can be replicated into traditional layered composites and are able to enhance the out-of-plane properties without a dangerous degradation of the in-plane properties.

In this work, we proposed a control moment generator, which is called Trailing Edge Change (TEC) mechanism, for attitudes change in hovering insect-like tailless flapping-wing MAV. The control moment generator was installed to the flapping-wing mechanism to manipulate the wing kinematics by adjusting the wing roots location symmetrically or asymmetrically. As a result, the mean aerodynamic force center of each wing is relocated and control moments are generated. The three-dimensional wing kinematics captured by three synchronized high-speed cameras showed that the flapping-wing MAV can properly modify the wing kinematics. In addition, a series of experiments were performed using a multi-axis load cell to evaluate the forces and moments generation. The measurement demonstrated that the TEC mechanism produced reasonable amounts of pitch, roll and yaw moments by shifting position of the trailing edges at the wing roots of the flapping-wing MAV.

New biological structures usually evolve from gradual modifications of old structures. Sometimes, biological structures contain hidden features, possibly vestigial. In addition to learning about functionalities, mechanisms, and structures readily apparent in nature, one must be alive to hidden features that could be useful. This aspect of engineered biomimicry is exemplified by two optical structures of psittacine and lepidopteran provenances. In both examples, a schemochrome is hidden by pigments.

Fecal incontinence is the involuntary loss of bowel content and affects more than 12% of the adult population, including 45% of retirement home residents. Severe fecal incontinence is often treated by implanting an artificial sphincter. Currently available implants, however, have long-term reoperation rates of 95% and definitive explantation rates of 40%. These statistics show that the implants fail to reproduce the capabilities of the natural sphincter and that the development of an adaptive, biologically inspired implant is required. Dielectric elastomer actuators (DEA) are being developed as artificial muscles for a biomimetic sphincter, due to their suitable response time, reaction forces, and energy consumption. However, at present the operation voltage of DEAs is too high for artificial muscles implanted in the human body. To reduce the operating voltage to tens of volts, we are using microfabrication to reduce the thickness of the elastomer layer to the nanometer level. Two microfabrication methods are being investigated: molecular beam deposition and electrospray deposition. This communication covers the current status and a perspective on the way forward, including the long-term prospects of constructing a smart sphincter from low-voltage sensors and actuators based on nanometer-thin dielectric elastomer films. As DEA can also provide sensory feedback, a biomimetic sphincter can be designed in accordance with the geometrical and mechanical parameters of its natural counterpart. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence du ring daily activities.

Photo-actuation, such as that observed in the reversible sun-tracking movements of heliotropic plants, is produced by a complex, yet elegant series of processes. In the heliotropic leaf movements of the Cornish Mallow, photo-actuation involves the generation, transport and manipulation of chemical signals from a distributed network of sensors in the leaf veins to a specialized osmosis driven actuation region in the leaf stem. It is theorized that such an arrangement is both efficient in terms of materials use and operational energy conversion, as well as being highly robust. We concern ourselves with understanding and mimicking these light driven, chemically controlled actuating systems with the aim of generating intelligent structures which share the properties of efficiency and robustness that are so important to survival in Nature. In this work we present recent progress in mimicking these photo-actuating systems through remote light exposure of a metastable state photoacid and the resulting signal and energy transfer through solution to a pH-responsive hydrogel actuator. Reversible actuation strains of 20% were achieved from this arrangement, with modelling then employed to reveal the critical influence hydrogel pKa has on this result. Although the strong actuation achieved highlights the progress that has been made in replicating the principles of biomimetic photo-actuation, challenges such as photoacid degradation were also revealed. It is anticipated that current work can directly lead to the development of high-performance and low-cost solartrackers for increased photovoltaic energy capture and to the creation of new types of intelligent structures employing chemical control systems.

Using a pair of antagonistic Shape Memory Allow (SMA) wires, it may be possible to produce a mechanism that replicates human musculoskeletal movement. The movement of interest is the articulation of the elbow joint actuated by the biceps brachii muscle. In an effort to understand the bio-mechanics of the arm, a single degree of freedom crankslider mechanism is used to model the movement of the arm induced by the biceps brachii muscle. First, a purely kinematical analysis is performed on a rigid body crank-slider. Force analysis is also done modeling the muscle as a simple linear spring. Torque, rocking angle, and energy are calculated for a range of crank-slider geometries. The SMA wire characteristics are experimentally determined for the martensite detwinned and full austenite phases. Using the experimental data, an idealized actuator characteristic curve is produced for the SMA wire. Kinematic and force analyses are performed on the nonlinear wire characteristic curve and a linearized wire curve; both cases are applied to the crankslider mechanism. Performance metrics for both cases are compared, followed by discussion.

Wireless sensor networks (WSNs) have emerged as a reliable, low-cost alternative to the traditional wired sensing paradigm. While such networks have made significant progress in the field of structural monitoring, significantly less development has occurred for feedback control applications. Previous work in WSNs for feedback control has highlighted many of the challenges of using this technology including latency in the wireless communication channel and computational inundation at the individual sensing nodes. This work seeks to overcome some of those challenges by drawing inspiration from the real-time sensing and control techniques employed by the biological central nervous system and in particular the mammalian cochlea. A novel bio-inspired wireless sensor node was developed that employs analog filtering techniques to perform time-frequency decomposition of a sensor signal, thus encompassing the functionality of the cochlea. The node then utilizes asynchronous sampling of the filtered signal to compress the signal prior to communication. This bio-inspired sensing architecture is extended to a feedback control application in order to overcome the traditional challenges currently faced by wireless control. In doing this, however, the network experiences high bandwidths of low-significance information exchange between nodes, resulting in some lost data. This study considers the impact of this lost data on the control capabilities of the bio-inspired control architecture and finds that it does not significantly impact the effectiveness of control.

Bird feathers are remarkable structures light but yet durable providing insulation and the ability of flight. Owls are highly specialized birds of prey, widely known for their ability to y silently which is enabled by (micro-) structural specializations of the feathers. The barn owl replaces feathers less frequently in comparison to other same sized birds like pigeons, indicating a much better resistance against material fatigue of these delicate microstructures. We used axisymmetric drop shape analysis (ADSA) of water drop contact angles as a non-destructive method of characterizing wearing processes in feathers. We hypothesized that feathers become more wettable when worn. We also investigated the impact of ethanol treatment in order to remove fatty residues of the uropygial gland secretions, barn owls and pigeons use for preening, on ageing processes. Ethanol treatment resulted in a slight, but significant increase of water repellency in barn owl but not in pigeon flight feathers. Our preliminary data also suggest that the uropygial gland secretions decelerate the wearing process of the feather keratin. We observed this effect in both species, however, it was more distinct for barn owl uropygial gland secretions. The results of this study, obtained by contact angle measurements used as a non-destructive evaluation method of material fatigue, yield insights into the material fatigue of feathers and the decelerating effect of uropygial gland secretions on wear on the other hand.

Cardiovascular diseases are the worldwide number one cause of mortality. The blood flow in diseased human coronary arteries differs from the blood flow in the healthy vessels. This fact should be used for designing targeted localized delivery of vasodilators with a purely physical drug release trigger. Thus, we have proposed mechano-sensitive liposomes as mechano-sensitive containers. One has to tailor the liposome’s properties, so that containers are stable under physiological conditions in health, but release their cargo near the constricted vessels at body temperature. In order to determine the shear stress threshold for release, both the morphology of the healthy and diseased human arteries and the mechanical property of the liposomes have to be known. We have shown that micro computed tomography (μCT) techniques allow visualizing the lumen of human coronary arteries and provide the basis for flow simulations to extract the wall shear stress of healthy and stenosed regions in human coronary arteries. The behavior of the mechano-sensitive liposomes is currently investigated by means of microfluidics and spatially resolved small-angle X-ray scattering. The liposomes are injected into micro-channels mimicking in vivo situation. The scattering signal from the liposomes reveals information about their size, shape, and wall thickness.

In this work, predictive model for a bio-inspired broadband frequency sensor is developed. Broadband frequency sensing is essential in many domains of science and technology. One great example of such sensor is human cochlea, where it senses a frequency band of 20 Hz to 20 KHz. Developing broadband sensor adopting the physics of human cochlea has found tremendous interest in recent years. Although few experimental studies have been reported, a true predictive model to design such sensors is missing. A predictive model is utmost necessary for accurate design of selective broadband sensors that are capable of sensing very selective band of frequencies. Hence, in this study, we proposed a novel predictive model for the cochlea-inspired broadband sensor, aiming to select the frequency band and model parameters predictively. Tapered plate geometry is considered mimicking the real shape of the basilar membrane in the human cochlea. The predictive model is intended to develop flexible enough that can be employed in a wide variety of scientific domains. To do that, the predictive model is developed in such a way that, it can not only handle homogeneous but also any functionally graded model parameters. Additionally, the predictive model is capable of managing various types of boundary conditions. It has been found that, using the homogeneous model parameters, it is possible to sense a specific frequency band from a specific portion (B) of the model length (L). It is also possible to alter the attributes of ‘B’ using functionally graded model parameters, which confirms the predictive frequency selection ability of the developed model.

Batoids, or rays, utilize unique forms of locomotion that may offer more efficient techniques of motorized propulsion in various marine environments. We present a novel biomimetic engineering design and assembly of a stingray-inspired robot swimmer. The robots locomotion mimics the Dasyatis americana, or southern stingray, whose distinction among rays is its intermediate motion, characterized by sweeping strokes that propagate between 1/2-1 wavelength of the fin profile in the posterior direction. Though oscillatory (<;1/2 wavelength) and undulatory (> wavelengths) ray-based robots have been created, this project demonstrates new engineering possibilities in what is, to the best of our knowledge, the first intermediately propelled batoid-based robot. The robots fins were made of silicone rubber, cast in a 3-D printed mold, with wingspan of 42 cm (1/2 - 1/5 scale for males and females, respectively, scale of model organism). Two anteriorly placed servomotors per fin were used, all controlled by one wirelessly enabled Arduino microcontroller. Each servomotor oscillated a flexible rod with cylindrical joint, whose frequency, speed, and front-back phase delay were user-programmed over wireless connection. During free-swimming tests, the fin profile developed about 0.8 wavelength, qualifying for successful mimicry of its biological inspiration. The robot satisfactorily maintained straight-line motion, reaching average peak velocity of 9.4±1.0 cm/s (0.27−0.03 body lengths/second) at its optimum flapping frequency of 1.4 Hz. This is in the same order of magnitude of speed normalized to body length achieved by others in two recent batoid-based projects. In summary, our robot performed intermediate stingray locomotion with relatively fewer components, which reveals robust potential for innovation of the simple intermediate batoid-based robot swimmer.

This paper presents a biomimetic, lightweight, 3D printed and customizable robotic hand with locking mechanism consisting of Twisted and Coiled Polymer (TCP) muscles based on nylon precursor fibers as artificial muscles. Previously, we have presented a small-sized biomimetic hand using nylon based artificial muscles and fishing line muscles as actuators. The current study focuses on an adult-sized prosthetic hand with improved design and a position/force locking system. Energy efficiency is always a matter of concern to make compact, lightweight, durable and cost effective devices. In natural human hand, if we keep holding objects for long time, we get tired because of continuous use of energy for keeping the fingers in certain positions. Similarly, in prosthetic hands we also need to provide energy continuously to artificial muscles to hold the object for a certain period of time, which is certainly not energy efficient. In this work we, describe the design of the robotic hand and locking mechanism along with the experimental results on the performance of the locking mechanism.

Smooth adhesive pad found among arthropods, amphibians, particularly tree frogs, are usually covered with surface microstructure of different shape to enhance the attachment abilities on the smooth substrate. During the last decade, it has gained more attentions in the development of anti-slippery systems by mimicking these unique characteristics. In this paper, we studied a new amphibian species newt by observing their climbing abilities on wet and dry vertical smooth surface, and found that the newts can even hang on the surface with an inclination angle more than 90° without falling. We investigated the toe pad micro-structured surface of the newt by using scanning electron microscopy (SEM), and found that an array of hexagonal cells with micro-ridges on cell borders exists for the larvae; while an array of hexagonal cells separated by microgrooves is for the adult. Inspired by these features, the biomimetic micro-structured surfaces were fabricated using a soft elastomeric material polydimethysiloxane (PDMS). Four different microstructures were chosen to study their tribological properties with a solid substrate under wet and dry conditions. The patterns of the microstructures include round pillar, hexagonal pillar, round pillars surrounded by a closed hexagonal ridge, and round pillars surrounded by a semi-closed hexagonal ridge. The static friction tests were carried out using the multi-functional surface meter TYPE12. The results showed that the area ratio of the micro pillar plays a major role in enhancing the static friction for both wet and dry conditions, while the numerical density of the micro pillar has less effect on the friction enhancement. Among the four kind specimens, the specimen with hexagonal pillars would increase the static friction more than others at the same test conditions when the pillar area ratio is lower than 40%.

Results are presented which demonstrate the feasibility and performance of two concepts of biologically-inspired landing-gear systems that enable bird-sized, unmanned aerial vehicles (UAV’s) to land, perch, and take-off from branchlike structures and/or ledges. The first concept follows the anatomy of birds that can grasp ahold of a branch and perch as tendons in their legs are tensioned. This design involves a gravity-activated, cable-driven, underactuated, graspingfoot mechanism. As the UAV lands, its weight collapses a four-bar linkage pulling a cable which curls two opposing, multi-segmented feet to grasp the landing target. Each foot is a single, compliant mechanism fabricated by simultaneouly 3D-printing a flexible thermo-plastic and a stiffer ABS plastic. The design is optimized to grasp structures over a range of shapes and sizes. Quasi-static and flight tests of this landing gear affixed to RC rotorcraft (24 cm to 550 cm in diameter) demonstrate that the aircraft can land, perch, and take-off from a tree branch, rectangular wood board, PVC pipe, metal hand rail, chair armrest, and in addition, a stone wall ledge. Stability tests show that perching is maintained under base and wind disturbances. The second design concept, inspired by roosting bats, is a two-material, 3D-printed hooking mechanism that enables the UAV to stably suspend itself from a wire or small-diameter branch. The design balances structural stiffness for support and flexibility for the perching process. A flight-test demonstrates the attaching and dis-engaging of a small, RC quadcopter from a suspended line.

A bioinspired robotic tongue which is actuated by a network of compressed air is proposed for the purpose of mimicking the movements of human tongue. It can be applied in the fields such as medical science and food engineering. The robotic tongue is made of two kinds of silicone rubber Ecoflex 0030 and PDMS with the shape simplified from real human tongue. In order to characterize the robotic tongue, a series of experiments were carried out. Laser scan was applied to reconstruct the static model of robotic tongue when it was under pressurization. After each scan, the robotic tongue was scattered into dense points in the same 3D coordinate system and the coordinates of each point were recorded. Motion tracking system (OptiTrack) was used to track and record the whole process of deformation dynamically during the loading and unloading phase. In the experiments, five types of deformation were achieved including roll-up, roll-down, elongation, groove and twist. Utilizing the discrete points generated by laser scan, the accurate parameterized outline of robotic tongue under different pressure was obtained, which could help demonstrate the static characteristic of robotic tongue. The precise deformation process under one pressure was acquired through the OptiTrack system which contains a series of digital cameras, markers on the robotic tongue and a set of hardware and software for data processing. By means of tracking and recording different process of deformation under different pressure, the dynamic characteristic of robotic tongue could be achieved.

In order to study how vibrations from ground vehicles/aircraft will impact on the seated occupants, it is of significance to develop an effective biodynamic model for the seated occupants. In this paper, a wide variety of 4-degree-of-freedom (4- DOF) lumped-parameter models for a seated occupant is investigated. A linear 4-DOF model with 18 parameters is deduced and employed as an example. The parameters of the 4-DOF model are identified based on the Pareto optimization principle. The goodness of fit (ε) is established and employed to evaluate the effectiveness of the models. Then, all possible linear 4-DOF models are analyzed and discussed with the same parameters identification and effectiveness evaluation. The most-effective two models are obtained and compared with two other existing models. The research results show that: (i) The total types of linear 4-DOF models is limited and all the parameters of models are identifiable; (ii) The number of parameters of the 4-DOF models affects little on the goodness of fit (ε); and (iii) The presented models are more effective than the two existing models.

In this paper, an insect wing structure is modeled based on data obtained from measurements on real hawkmoth (Manduca Sexta) wings. The aerodynamics of insect wings is simulated by an extended unsteady vortex-lattice method. The finite-element model of a flexible hawkmoth wing is built and validated. A computer program, which couples the finite-element model with the aerodynamic model, is used to study the effects of fluid-structure interaction. Some important features due to the fluid-structure interaction in hovering and forward flight are observed in the present study.

Moisture-harvesting lizards, such as the Texas horned lizard Phrynosoma cornutum, have remarkable adaptations for inhabiting arid regions. Special skin structures, in particular capillary channels in between imbricate overlapping scales, enable the lizard to collect water by capillarity and to transport it to the snout for ingestion. This fluid transport is passive and directional towards the lizard's snout. The directionality is based on geometric principles, namely on a periodic pattern of interconnected half-open capillary channels that narrow and widen. Following a biomimetic approach, these principles were transferred to technical prototype design and manufacturing. Capillary structures, 50 μm to 300 μm wide and approx. 70 μm deep, were realized by use of a pulsed picosecond laser in hot working tool steel, hardened to 52 HRC. In order to achieve highest functionality, strategies were developed to minimize potential structural inaccuracies, which can occur at the bottom of the capillary structures caused by the laser process. Such inaccuracies are in the range of 10 μm to 15 μm and form sub-capillary structures with greater capillary forces than the main channels. Hence, an Acceleration Compensation Algorithm was developed for the laser process to minimize or even avoid these inaccuracies. The capillary design was also identified to have substantial influence; by a hexagonal capillary network of non-parallel capillaries potential influences of sub-capillaries on the functionality were reduced to realize a robust passive directional capillary transport. Such smart surface structures can lead to improvements of technical systems by decreasing energy consumption and increasing the resource efficiency.

The purpose of this paper is to develop load assisting clothes for caregivers. Low back pain is one of the most major reasons for caregivers to leave their jobs. In this study, load assisting clothes which reduce the risks of low back pain of caregivers are designed and manufactured, targeting at the use in small care-houses and family caregiving. The load assisting clothes should have two functions. One is to reduce the compressive load acting on the lumbar spine as well as the tensile load on the lumbar muscles by providing an appropriate assisting force. The other is not to interfere with wearers’ motion. The proposed approach in this study is to put elastic compressive members and tensioner belts integrated in the garment to provide the assisting forces without hindering natural movement and comfortable feeling. We study human musculoskeletal systems in the lumbar part, and consider to construct a parallel reinforcement of it on the body surface by embedding passive support structures. The arrangement of those elements is determined based on the study of the principal strain directions and the non-extension directions of the body surface to manage the appropriate assisting force without spoiling the mobility. The effectiveness of the proposed support principle is verified through experimental studies.

Gills are one of the most primitive gas, solute exchange organs available in fishes. They facilitate exchange of gases, solutes and ions with a surrounding water medium through their functional unit called secondary lamella. These lamellae through their extraordinary morphometric features and peculiar arrangement in gills, achieve remarkable mass transport properties. Therefore, in the current study, modeling and simulation of convection-diffusion transport through a two dimensional model of secondary lamella and theoretical analysis of morphometric features of fish gills were carried out. Such study suggested an evolutionary conservation of parametric ratios across fishes of different weights. Further, we have also fabricated a thin microvascularised PDMS matrices mimicking secondary lamella by use of micro-technologies like electrospinning. In addition, we have also demonstrated the fluid flow by capillary action through these thin microvascularised PDMS matrices. Eventually, we also illustrated the application of these thin microvascularied PDMS matrices in solute exchange process under capillary flow conditions. Thus, our study suggested that fish gills have optimized parameteric ratios, at multiple length scale, throughout an evolution to achieve an organ with enhanced mass transport capabilities. Thus, these defined parametric ratios could be exploited to design and develop efficient, scaled-up gas/solute exchange microdevices. We also proposed an inexpensive and scalable method of fabrication of thin microvascularised polymer matrices and demonstrated its solute exchange capabilities under capillary flow conditions. Thus, mimicking the microstructures of secondary lamella will enable fabrication of microvascularised thin polymer systems through micro manufacturing technologies for potential applications in filtration, self-healing/cooling materials and bioengineering.