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This paper explores how Biologically Inspired Design (BID) can be applied in the development of medical devices through a concrete case study. Nature has been developing, over the last 3.8 billion years, the most efficient mechanisms to fulfil a function and overcome challenges. Based on this giant innovation database, BID has received an exponential increase of interest since the 1950s and has led to innovative solutions in a vast variety of fields. The present study is motivated by a medical device which should be designed for insertion in a cavity, followed by a significant expansion inside the cavity. Once expanded, the device should be able to radiate light for disinfection purposes, while simultaneously allowing air replacement in the cavity. Finally, the device should contract to its original size before being extracted from the cavity. In order to propose radically new ideas for designing such a device, BID is applied to a range of functions namely i) how to expand an object after insertion in a cavity, ii) how to promote air circulation in the cavity, iii) how to radiate light to all surfaces in the cavity and finally iv) how to contract the object again. This paper presents and discusses the BID process as well as the outcomes of this study. 25 biological strategies have been identified throughout the project, 7 ideas were generated and 4 more detailed concepts and physical mock-ups emerged from these ideas. 2 of them were considered interesting for further development, which indicates a good efficacy of the process. The whole study lasted 32 working days, suggesting a high efficiency of the BID process.

The use of electricity is so pervasive that life without it is unimaginable today. The scope of electricity is even widening to encompass wearables and draperies in domestic and professional surroundings. The typical way of conducting electricity is through metallic wires and conduits, which often are integrated permanently into engineered products. This means that we have more and more products with mixed materials that are difficult to recycle, thereby creating a major bottleneck towards the achievement of sustainable urban and rural environments. If electricity could be conducted in another way, new design options would become possible. The bioworld offers ways for conducting electricity without metallic interconnects. Examples range from electric discharges by electric eels to electrolocation by fish to bacterial protein networks that conduct electrons. A review of electrical conduction mechanisms in the bioworld suugests the feasibility of incorporating the underlying bioworld principles in engineered products.

A controllable magnetochromic elastomer is developed by dissolving magnetic nanoparticles (MNPs) in poly(ethylene glycol)-200 (PEG-200) and emulsifying the solution in polydimethylsiloxane (PDMS) using a high-shear Speedmixer. The MNPs are aligned in order along the direction of the externally applied magnetic field, causing the material to become transparent and realizing a switch on/off function. Both particle size and size distribution were observed to affect magnetochromic response, and use of an ultrasonication bath was shown to prohibit MNP agglomerations. In addition, the surfactant surface-modified MNPs synthesized via co-precipitation were shown to possess both a smaller primary size and a narrower size distribution compared to non-treated commercial MNPs, leading to improved MNP dispersion stability in PEG-200. The optimized silicone elastomer—with 40 parts per hundred rubber (phr) PEG-200 and 3 wt% MNPs modified by citric acid surfactant—exhibits instantaneous and reversible color change when exposed to an external magnetic field. The color changing efficiency and fast response time of the magnetochromic elastomer developed here are suited to a variety of color tuning applications: e.g., bio-sensors and anticounterfeiting labels.

We have heavily relied for a few centuries on fossil fuels, which are basically dead plant material that was sequestered and converted millions of years ago, but the rapidly increasing energy demand combined with climatic challenges means we need to develop a large-scale supply of energy from sources without climatic impact. An obvious choice is to use solar energy directly when possible, and a complete global transition to solar energy by 2050 is realistic and cost effective. However, in order to find space for the large areas needed for harvesting solar energy by photovoltaic means, it would be advantageous if solar panels could be incorporated into urban buildings and free land for other uses. We undertook an analysis of the needs and requirements from the building industry that will allow for a more widespread use of solar panels on buildings, also referred to as Building Integrated Photo-Voltaics. Specifications and options for the visual incorporation of the solar panels in the building envelope were identified. Special attention was paid to (i) the role of modularization and standardization in architecture and (ii) the role of color and reflectance. A standardized mounting system is proposed that will allow for modular attachment of solar panels, making it easy to adjust, repair, and replace individual panels. Biological inspiration can be used to improve the system further. The forced-air ventilation of the tunnels of prairie dogs shows how to enhance cooling. The non-iridescent wings of butterflies of the Morpho genus, proposes how a low-cost structurally colored film can be inserted into the solar panel during its assembly.

A coupled optoelectronic model was implemented along with the differential evolution algorithm to assess the efficacy of grading the bandgap of the Cu2ZnSn(SξSe1–ξ)4 (CZTSSe) layer for enhancing the power conversion efficiency of thin-film CZTSSe solar cells. Both linearly and sinusoidally graded bandgaps were examined, with the molybdenum backreflector in the solar cell being either planar or periodically corrugated. Whereas an optimally graded bandgap can dramatically enhance the efficiency, the effect of periodically corrugating the backreflector is modest at best. An efficiency of 21.74% is predicted with sinusoidal grading of a 870 nm thick CZTSSe layer, in comparison to 12.6% efficiency achieved experimentally with a 2200 nm thick homogeneous CZTSSe layer. High electron-hole-pair generation rates in the narrow-bandgap regions and a high open-circuit voltage due to a wider bandgap close to the front and rear faces of the CZTSSe layer are responsible for the high enhancement of efficiency.

An optoelectronic optimization was carried out for an AlξGa1−ξAs (AlGaAs) solar cell containing (i) an n-AlGaAs absorber layer with a graded bandgap and (ii) a periodically corrugated Ag backreflector combined with localized ohmic Pd–Ge–Au backcontacts. The bandgap of the absorber layer was varied either sinusoidally or linearly. An efficiency of 33.1% with the 2000-nm-thick n-AlGaAs absorber layer is predicted with linearly graded bandgap along with silver backreflector and localized ohmic backcontacts, in comparison to 27.4% efficiency obtained with homogeneous bandgap and a continuous ohmic backcontact. Sinusoidal grading of the bandgap is predicted to enhance the maximum efficiency to 34.5%. Thus, grading the bandgap of the absorber layer, along with a periodically corrugated Ag backreflector and localized ohmic Pd-Ge-Au backcontacts, can help realize ultrathin and high-efficient AlGaAs solar cells for terrestrial applications.

Design for Environment (DfE or ecodesign) aims at developing products with an enhanced environmental performance, without compromising functionality and other key requirements (such as cost and quality). Common DfE guidelines for product design include: reduction of material diversity, extension of useful life (e.g., by enabling repair and upgrade), avoidance of toxic materials and nonrenewable resources, use of recycled components, and ease of disassembly and recyclability after the end of useful life. DfE requires the integration of environmental considerations into the traditional design processes, supporting decisions that could enhance the environmental profile of the product. Biologically-inspired- design (BID) teams identify and isolate the core principles of relevance for systems, products, and processes from the bioworld for consideration and possible incorporation during each of the design stages. Synergies and potential trade-offs existing between DfE and BID must be considered when integrating the two methodologies into Biologically Inspired Design for Environment for the design of products and systems.

We study the convergence properties of the two-dimensional Rigorous Coupled Wave Approach (RCWA) for p-polarized monochromatic incident light. The RCWA is a semi-analytical numerical method that is widely used to solve the boundary-value problem of scattering by a grating. The approach requires the expansion of all electromagnetic field phasors and the relative permittivity as Fourier series in the spatial variable along the direction of the periodicity of the grating. In the direction perpendicular to the grating periodicity, the domain is discretized into thin slices and the actual relative permittivity is replaced by an approximation. The approximate relative permittivity is chosen so that the solution of the Maxwell equations in each slice can be computed without further approximation. Thus, there is error due to the approximate relative permittivity as well as the trucation of the Fourier series. We show that the RCWA embodies a Galerkin scheme for a perturbed problem, and then we use tools from the Finite Element Method to show that the method converges with increasing number of retained Fourier modes and finer approximations of the relative permittivity. Numerical examples illustrate our analysis, and suggest further work.

Photovoltaic solar cells generally have a black or blue appearance that makes them aesthetically very different from traditional rooftops that either comprise burned-clay tiles or composite-material shingles. Rooftop solar cells may become more acceptable if they are colored, e.g., red or bluish green. This objective requires that a certain part of the incoming solar spectrum be reflected. The reflected part becomes unavailable for photovoltaic generation of electricity. We implemented and optimized an optoelectronic model for Cu2ZnSn(SζSe1-ζ )4 (CZTSSe) solar cells containing (i) a conventional 2200-nm-thick CZTSSe layer with homogeneous bandgap, or (ii) a ultrathin CZTSSe layer with optoelectronically optimized sinusoidally nonhomogeneous bandgap, or (iii) a CZTSSe layer with optoelectronically optimized linearly nonhomogeneous bandgap. Either complete or partial rejection of either red or bluish green photons was incorporated in the model. Calculations show that on average, the efficiency of a typical solar cell will be reduced by 9% if 50% red photons are reflected or by 12% if 50% blue-green photons are reflected. The efficiency reduction increases to 20% if all red photons are reflected or 25% if all blue-green photons are reflected.

Silicon photovoltaic solar cells generally have a black or blue appearance that makes them aesthetically very different from traditional red roofs that either comprise burned-clay tiles or composite-material shingles. Rooftop solar cells may become more acceptable if they are similar in appearance to traditional roofs. This objective requires that the red part (620–700 nm wavelength) of the incoming solar spectrum be reflected so that it becomes unavailable for photovoltaic generation of electricity. Complete reflection of red photons would result in the reduction of useful solar photons (300– 1200 nm wavelength) by 12.5%. Calculations show that the optical short-circuit density will then decline by: 17% for 100-μm-thick crystalline-silicon solar cells, 20–22% for triple-junction tandem thin-film solar cells of amorphous silicon, 15-16% for 2.2-μm-thick CIGS solar cells, and 16–20% for ultrathin CIGS solar cells. On average, the efficiency of a typical solar cell will have to be multiplied by a factor of 0.8 if all red photons were reflected. This reduction in efficiency can be offset by wider adoption of rooftop solar cells. Red-rejection filters can be made of particulate composite materials containing, say, silica nanospheres. Typically, the solar cells will be iridescent then, which may not be aesthetically pleasing to many. Non-iridescent red-rejection filters can be fabricated by upscaling the linear dimensions of biomimetic filters nano-imprinted to reproduce the Morpho blue, this possibility being guaranteed by the scale invariance of the Maxwell equations and the weak dispersion of the refractive indexes of numerous polymers in the visible spectral regime. Non-uniformly red rooftop solar cells would also become feasible.

The incorporation of materials with controllable electromagnetic constitutive parameters allows the conceptualization and realization of controllable metasurfaces. With the aim of formulating and investigating a tricontrollable metasurface for efficiently absorbing terahertz radiation, we adopted a pixel-based approach in which the meta-atoms are biperiodic assemblies of discrete pixels. We patched some pixels with indium antimonide (InSb) and some with graphene, leaving the others unpatched. The bottom of each meta-atom was taken to comprise a metal-backed substrate of silicon nitride. The InSb-patched pixels facilitate the thermal and magnetic control modalities, whereas the graphene-patched pixels facilitate the electrical control modality. With proper configuration of patched and unpatched pixels, and with proper selection of the patching material for each patched pixel, the absorptance spectra of the pixelated metasurface were found to contain peak-shaped features with maximum absorptance exceeding 0.95, full-width-at-half-maximum bandwidth of less than 0.7 THz, and maximum-absorptance frequency lying between 2 THz and 4 THz. The location of the maximum-absorptance frequency can be thermally, magnetically, and electrically controllable. The lack of rotational invariance of the optimal meta-atom adds mechanical rotation as the fourth control modality.

Dyakonov-Voigt (DV) surface waves guided by the planar interface of (i) material A, which is a uniaxial dielectric material specified by a relative permittivity dyadic with eigenvalues epsilon(s)(A) and epsilon(t)(A), and (ii) material B, which is an isotropic dielectric material with relative permittivity epsilon(B), are numerically investigated by solving the corresponding canonical boundary-value problem. The two partnering materials were generally dissipative, with the optic axis of material A being inclined at the angle chi is an element of [0 degrees, 90 degrees] relative to the interface plane. No solutions of the dispersion equation for DV surface waves exist when chi = 90 degrees. Also, no solutions exist for chi is an element of (0 degrees, 90 degrees), when both partnering materials are nondissipative. For chi is an element of [0 degrees, 90 degrees), the degree of dissipation of material A has a profound effect on the phase speeds, propagation lengths, and penetration depths of the DV surface waves. For mid-range values of chi, DV surface waves with negative phase velocities were found. For fixed values of epsilon(s)(A) and epsilon(t)(A) in the upper-half-complex plane, DV surface-wave propagation is only possible for large values of chi when vertical bar epsilon(B)vertical bar is very small. (C) 2019 Optical Society of America

Biologically inspired design is attracting increasing interest since it offers access to a huge biological repository of wellproven design principles that can be used for developing new and innovative products. Biological phenomena can inspireproduct innovation in as diverse areas as mechanical engineering, medical engineering, nanotechnology, photonics,environmental protection and agriculture. However, a major obstacle for the wider use of biologically inspired design isthe knowledge barrier that exist between the application engineers that have insight into how to design suitable productsand the biologists with detailed knowledge and experience in understanding how biological organisms function in theirenvironment. The biologically inspired design process can therefore be approached using different design paradigmsdepending on the dominant opportunities, challenges and knowledge characteristics. Design paradigms are typicallycharacterized as either problem-driven, solution-driven, sustainability driven, bioreplication or a combination of two ormore of them. The design paradigms represent different ways of overcoming the knowledge barrier and the present paperpresents a review of their characterization and application.

The stinging proboscis in mosquitos have diameters of only 40-100 μm which is much less than the thinnest medical needles and the mechanics of these natural stinging mechanisms have therefore attracted attention amongst developers of injection devises. The mosquito use a range of different strategies to lower the required penetration force hence allowing a thinner and less stiff proboscis structure. Earlier studies of the mosquito proboscis insertion strategies have shown how each of the single strategies reduces the required penetration force. The present paper gives an overview of the advanced set of mechanisms that allow the mosquito to penetrate human skin and also presents other biological mechanisms that facilitate skin penetration. Results from experiments in a skin mimic using biomimetic equivalents to the natural mechanisms are presented. This includes skin stretching, insertion speed and vibration. Combining slow insertion speed with skin tension and slow vibration reduces the penetration force with 40%

Engineered Biomimicry covers a broad range of research topics in the emerging discipline of biomimicry. Biologically inspired science and technology, using the principles of math and physics, has led to the development of products as ubiquitous as Velcro™ (modeled after the spiny hooks on plant seeds and fruits). Readers will learn to take ideas and concepts like this from nature, implement them in research, and understand and explain diverse phenomena and their related functions. From bioinspired computing and medical products to biomimetic applications like artificial muscles, MEMS, textiles and vision sensors, Engineered Biomimicry explores a wide range of technologies informed by living natural systems. Engineered Biomimicry helps physicists, engineers and material scientists seek solutions in nature to the most pressing technical problems of our times, while providing a solid understanding of the important role of biophysics. Some physical applications include adhesion superhydrophobicity and self-cleaning, structural coloration, photonic devices, biomaterials and composite materials, sensor systems, robotics and locomotion, and ultra-lightweight structures. Explores biomimicry, a fast-growing, cross-disciplinary field in which researchers study biological activities in nature to make critical advancements in science and engineering Introduces bioinspiration, biomimetics, and bioreplication, and provides biological background and practical applications for each Cutting-edge topics include bio-inspired robotics, microflyers, surface modification and more

Engineered Biomimicry covers a broad range of research topics in the emerging discipline of biomimicry. Biologically inspired science and technology, using the principles of math and physics, has led to the development of products as ubiquitous as Velcro™ (modeled after the spiny hooks on plant seeds and fruits). Readers will learn to take ideas and concepts like this from nature, implement them in research, and understand and explain diverse phenomena and their related functions. From bioinspired computing and medical products to biomimetic applications like artificial muscles, MEMS, textiles and vision sensors, Engineered Biomimicry explores a wide range of technologies informed by living natural systems. Engineered Biomimicry helps physicists, engineers and material scientists seek solutions in nature to the most pressing technical problems of our times, while providing a solid understanding of the important role of biophysics. Some physical applications include adhesion superhydrophobicity and self-cleaning, structural coloration, photonic devices, biomaterials and composite materials, sensor systems, robotics and locomotion, and ultra-lightweight structures. Explores biomimicry, a fast-growing, cross-disciplinary field in which researchers study biological activities in nature to make critical advancements in science and engineering Introduces bioinspiration, biomimetics, and bioreplication, and provides biological background and practical applications for each Cutting-edge topics include bio-inspired robotics, microflyers, surface modification and more

Engineered Biomimicry covers a broad range of research topics in the emerging discipline of biomimicry. Biologically inspired science and technology, using the principles of math and physics, has led to the development of products as ubiquitous as Velcro™ (modeled after the spiny hooks on plant seeds and fruits). Readers will learn to take ideas and concepts like this from nature, implement them in research, and understand and explain diverse phenomena and their related functions. From bioinspired computing and medical products to biomimetic applications like artificial muscles, MEMS, textiles and vision sensors, Engineered Biomimicry explores a wide range of technologies informed by living natural systems. Engineered Biomimicry helps physicists, engineers and material scientists seek solutions in nature to the most pressing technical problems of our times, while providing a solid understanding of the important role of biophysics. Some physical applications include adhesion superhydrophobicity and self-cleaning, structural coloration, photonic devices, biomaterials and composite materials, sensor systems, robotics and locomotion, and ultra-lightweight structures. Explores biomimicry, a fast-growing, cross-disciplinary field in which researchers study biological activities in nature to make critical advancements in science and engineering Introduces bioinspiration, biomimetics, and bioreplication, and provides biological background and practical applications for each Cutting-edge topics include bio-inspired robotics, microflyers, surface modification and more

Self-organisation appeals to humans because difficult and repeated actions can be avoided through automation via bottom-up nonhierarchical processes. This is in contrast to the top-level controlled action strategy normally applied in automated products and in manufacturing. There are many situations where it is required that objects perform an action dependent on external stimuli. An example is automatic window blinds that open or closes in response to sunlight level. However, simpler and more robust designs could be made using the self-organising principles for movement found in many plants. Plants move to adapt to external conditions, e.g. sun-flower buds tracking the sun, touch-me-not Mimosa and Venus fly trap responding to mechanical stimuli by closing leaves to protect them and capture insects respectively. This paper describes 3 of the basic biomimetic principles used by plants to track the sun; i) light causing an inhibiting effect on the illuminated side causing it to bend, ii) light inducing a signal from the illuminated side that causes an action on the darker side and iii) light illuminating a number of sensing plates pointing upwards at an angle activate an expansion on the same side. A concept for mimicking the second principle is presented. It is a very simple and possible reliable self-organising structure that aligns a plate perpendicular to the source of illumination. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

For decades, the surface-plasmon-polariton wave guided by the interface of simple isotropic materials dominated the scene. However, in recent times research on electromagnetic surface waves guided by planar interfaces has expanded into new and exciting areas. In the 1990's research focused on advancing knowledge of the newly discovered Dyakonov wave. More recently, much of the surface wave research is motivated by the proliferation of nanotechnology and the growing number of materials available with novel properties. This book leads the reader from the relatively simple surface-plasmon-polariton wave with isotropic materials to the latest research on various types of electromagnetic surface waves guided by the interfaces of complex materials enabled by recent developments in nanotechnology. This includes: Dyakonov waves guided by interfaces formed with columnar thin films, Dyakonov-Tamm waves guided by interfaces formed with sculptured thin films, and multiple modes of surface-plasmon-polariton waves guided by the interface of a metal and a periodically varying dielectric material. Gathers research from the past 5 years in a single comprehensive view of electromagnetic surface waves. Written by the foremost experts and researchers in the field. Layered presentation explains topics with an introductory overview level up to a highly technical level.

For decades, the surface-plasmon-polariton wave guided by the interface of simple isotropic materials dominated the scene. However, in recent times research on electromagnetic surface waves guided by planar interfaces has expanded into new and exciting areas. In the 1990's research focused on advancing knowledge of the newly discovered Dyakonov wave. More recently, much of the surface wave research is motivated by the proliferation of nanotechnology and the growing number of materials available with novel properties. This book leads the reader from the relatively simple surface-plasmon-polariton wave with isotropic materials to the latest research on various types of electromagnetic surface waves guided by the interfaces of complex materials enabled by recent developments in nanotechnology. This includes: Dyakonov waves guided by interfaces formed with columnar thin films, Dyakonov-Tamm waves guided by interfaces formed with sculptured thin films, and multiple modes of surface-plasmon-polariton waves guided by the interface of a metal and a periodically varying dielectric material. Gathers research from the past 5 years in a single comprehensive view of electromagnetic surface waves. Written by the foremost experts and researchers in the field. Layered presentation explains topics with an introductory overview level up to a highly technical level.

For decades, the surface-plasmon-polariton wave guided by the interface of simple isotropic materials dominated the scene. However, in recent times research on electromagnetic surface waves guided by planar interfaces has expanded into new and exciting areas. In the 1990's research focused on advancing knowledge of the newly discovered Dyakonov wave. More recently, much of the surface wave research is motivated by the proliferation of nanotechnology and the growing number of materials available with novel properties. This book leads the reader from the relatively simple surface-plasmon-polariton wave with isotropic materials to the latest research on various types of electromagnetic surface waves guided by the interfaces of complex materials enabled by recent developments in nanotechnology. This includes: Dyakonov waves guided by interfaces formed with columnar thin films, Dyakonov-Tamm waves guided by interfaces formed with sculptured thin films, and multiple modes of surface-plasmon-polariton waves guided by the interface of a metal and a periodically varying dielectric material. Gathers research from the past 5 years in a single comprehensive view of electromagnetic surface waves. Written by the foremost experts and researchers in the field. Layered presentation explains topics with an introductory overview level up to a highly technical level.

Nanotechnology talk is moving out of its comfort zone of scientific discourse. As new products go to market and national and international organizations roll out public engagement programs on nanotechnology to discuss environmental and health issues, various sectors of the public are beginning to discuss what all the fuss is about. Non-Governmental Organizations have long since reacted; however, now the social sciences have begun to study the cultural phenomenon of nanotechnology, thus extending discourses and opening out nanotechnology to whole new social dimensions. We report here on these social dimensions and their new constructed imaginings, each of which is evident in the ways in which discourses around nanotechnology intersects with the economy, ecology, health, governance, and imagined futures. We conclude that there needs to be more than just an ‘environmental, legal and social implications’, or ‘ELSI’, sideshow within nanotechnology. The collective public imaginings of nanotechnology include tangles of science and science fiction, local enterprise and global transformation, all looking forward towards a sustainable future, while looking back on past debates about science and nature. Nanotechnology is already very much embedded in the social fabric of our life and times.

Nanotechnology talk is moving out of its comfort zone of scientific discourse. As new products go to market and national and international organizations roll out public engagement programs on nanotechnology to discuss environmental and health issues, various sectors of the public are beginning to discuss what all the fuss is about. Non-Governmental Organizations have long since reacted; however, now the social sciences have begun to study the cultural phenomenon of nanotechnology, thus extending discourses and opening out nanotechnology to whole new social dimensions. We report here on these social dimensions and their new constructed imaginings, each of which is evident in the ways in which discourses around nanotechnology intersects with the economy, ecology, health, governance, and imagined futures. We conclude that there needs to be more than just an ‘environmental, legal and social implications’, or ‘ELSI’, sideshow within nanotechnology. The collective public imaginings of nanotechnology include tangles of science and science fiction, local enterprise and global transformation, all looking forward towards a sustainable future, while looking back on past debates about science and nature. Nanotechnology is already very much embedded in the social fabric of our life and times.

Nanotechnology talk is moving out of its comfort zone of scientific discourse. As new products go to market and national and international organizations roll out public engagement programs on nanotechnology to discuss environmental and health issues, various sectors of the public are beginning to discuss what all the fuss is about. Non-Governmental Organizations have long since reacted; however, now the social sciences have begun to study the cultural phenomenon of nanotechnology, thus extending discourses and opening out nanotechnology to whole new social dimensions. We report here on these social dimensions and their new constructed imaginings, each of which is evident in the ways in which discourses around nanotechnology intersects with the economy, ecology, health, governance, and imagined futures. We conclude that there needs to be more than just an ‘environmental, legal and social implications’, or ‘ELSI’, sideshow within nanotechnology. The collective public imaginings of nanotechnology include tangles of science and science fiction, local enterprise and global transformation, all looking forward towards a sustainable future, while looking back on past debates about science and nature. Nanotechnology is already very much embedded in the social fabric of our life and times.

Nanotechnology talk is moving out of its comfort zone of scientific discourse. As new products go to market and national and international organizations roll out public engagement programs on nanotechnology to discuss environmental and health issues, various sectors of the public are beginning to discuss what all the fuss is about. Non-Governmental Organizations have long since reacted; however, now the social sciences have begun to study the cultural phenomenon of nanotechnology, thus extending discourses and opening out nanotechnology to whole new social dimensions. We report here on these social dimensions and their new constructed imaginings, each of which is evident in the ways in which discourses around nanotechnology intersects with the economy, ecology, health, governance, and imagined futures. We conclude that there needs to be more than just an ‘environmental, legal and social implications’, or ‘ELSI’, sideshow within nanotechnology. The collective public imaginings of nanotechnology include tangles of science and science fiction, local enterprise and global transformation, all looking forward towards a sustainable future, while looking back on past debates about science and nature. Nanotechnology is already very much embedded in the social fabric of our life and times.

Nanotechnology talk is moving out of its comfort zone of scientific discourse. As new products go to market and national and international organizations roll out public engagement programs on nanotechnology to discuss environmental and health issues, various sectors of the public are beginning to discuss what all the fuss is about. Non-Governmental Organizations have long since reacted; however, now the social sciences have begun to study the cultural phenomenon of nanotechnology, thus extending discourses and opening out nanotechnology to whole new social dimensions. We report here on these social dimensions and their new constructed imaginings, each of which is evident in the ways in which discourses around nanotechnology intersects with the economy, ecology, health, governance, and imagined futures. We conclude that there needs to be more than just an ‘environmental, legal and social implications’, or ‘ELSI’, sideshow within nanotechnology. The collective public imaginings of nanotechnology include tangles of science and science fiction, local enterprise and global transformation, all looking forward towards a sustainable future, while looking back on past debates about science and nature. Nanotechnology is already very much embedded in the social fabric of our life and times.

Nanotechnology talk is moving out of its comfort zone of scientific discourse. As new products go to market and national and international organizations roll out public engagement programs on nanotechnology to discuss environmental and health issues, various sectors of the public are beginning to discuss what all the fuss is about. Non-Governmental Organizations have long since reacted; however, now the social sciences have begun to study the cultural phenomenon of nanotechnology, thus extending discourses and opening out nanotechnology to whole new social dimensions. We report here on these social dimensions and their new constructed imaginings, each of which is evident in the ways in which discourses around nanotechnology intersects with the economy, ecology, health, governance, and imagined futures. We conclude that there needs to be more than just an ‘environmental, legal and social implications’, or ‘ELSI’, sideshow within nanotechnology. The collective public imaginings of nanotechnology include tangles of science and science fiction, local enterprise and global transformation, all looking forward towards a sustainable future, while looking back on past debates about science and nature. Nanotechnology is already very much embedded in the social fabric of our life and times.

A study of ray trajectories was undertaken for the Tamm medium which represents the spacetime of a cosmic spinning string, under the geometric-optics approximation. Our numerical studies revealed that: (i) rays never cross the string's boundary; (ii) the Tamm medium supports evanescent waves in regions of phase space that correspond to those regions of the string's spacetime which could support closed timelike curves; and (iii) a spinning string can be slightly visible while a non-spinning string is almost perfectly invisible.

A study of ray trajectories was undertaken for the Tamm medium which represents the spacetime of a cosmic spinning string, under the geometric-optics approximation. Our numerical studies revealed that: (i) rays never cross the string's boundary; (ii) the Tamm medium supports evanescent waves in regions of phase space that correspond to those regions of the string's spacetime which could support closed timelike curves; and (iii) a spinning string can be slightly visible while a non-spinning string is almost perfectly invisible.

We report the simultaneous control of the polarization state and emission bandwidth of colloidal nanocrystal quantum dots by embedding them in chiral reflector-based microcavities. Significant improvements in directionality and color purity have been observed in the polarized light output arising from the enhanced coupling between the NQD-excitons and the confined electromagnetic field., Presented at the 2007 Conference on Lasers and Electro-Optics, 6 May 2007.

The presence of charge promotes the propensity of a rotating black hole to support the propagation of electromagnetic plane waves with negative phase velocity (NPV) in its ergosphere, whether the Kerr-Newman or the Kerr-Sen metric descriptions of spacetime are considered. Striking differences in the NPV characteristics for the Kerr-Newman and Kerr-Sen metrics emerge from numerical studies, particularly close to the outer event horizon when the magnitude of the charge is large.

The presence of charge promotes the propensity of a rotating black hole to support the propagation of electromagnetic plane waves with negative phase velocity (NPV) in its ergosphere, whether the Kerr-Newman or the Kerr-Sen metric descriptions of spacetime are considered. Striking differences in the NPV characteristics for the Kerr-Newman and Kerr-Sen metrics emerge from numerical studies, particularly close to the outer event horizon when the magnitude of the charge is large.

The propagation of electromagnetic plane waves with negative phase velocity (NPV) is considered in Schwarzschild-(anti-)de Sitter spacetime. It is demonstrated that NPV propagation occurs in Schwarzschild-de Sitter spacetime at lower values of the cosmological constant than is the case for de Sitter spacetime. Furthermore, we report that neither is NPV propagation observed in Schwarzschild-anti-de Sitter spacetime, nor is it possible outside the event horizon of a Schwarzschild blackhole., Comment: Typographical error in eq (34) of EPL version is corrected in arxiv version. Europhysics Letters (accepted for publication)

The propagation of electromagnetic plane waves with negative phase velocity (NPV) in the ergosphere of a rotating black hole has recently been reported. A comparison of NPV propagation and superradiance is presented. We show that, although both phenomenons involve negative energy densities, there are two significant differences between them., Comment: Figure 2 in the version published in Phys Lett A is corrected in the arxiv version

We report on the occurrence of negative-phase-velocity (NPV) planewave propagation in the ergosphere of a rotating black hole. By implementing the Kerr metric, it is demonstrated that regions of NPV propagation are concentrated at the equator of the ergosphere, while NPV propagation is less common towards the polar regions. Increasing the angular velocity of the black hole exaggerates the NPV concentration at the equator. NPV propagation is not observed outside the stationary limit surface., Comment: Typographical error in eq (51) of NJP version is corrected in arxiv version

The propagation of electromagnetic plane waves with negative phase velocity (NPV) in the ergosphere of a rotating black hole has recently been reported. A comparison of NPV propagation and superradiance is presented. We show that, although both phenomenons involve negative energy densities, there are two significant differences between them., Comment: Figure 2 in the version published in Phys Lett A is corrected in the arxiv version

The propagation of electromagnetic plane waves with negative phase velocity (NPV) is considered in Schwarzschild-(anti-)de Sitter spacetime. It is demonstrated that NPV propagation occurs in Schwarzschild-de Sitter spacetime at lower values of the cosmological constant than is the case for de Sitter spacetime. Furthermore, we report that neither is NPV propagation observed in Schwarzschild-anti-de Sitter spacetime, nor is it possible outside the event horizon of a Schwarzschild blackhole., Comment: Typographical error in eq (34) of EPL version is corrected in arxiv version. Europhysics Letters (accepted for publication)

The propagation of electromagnetic plane waves with negative phase velocity (NPV) in the ergosphere of a rotating black hole has recently been reported. A comparison of NPV propagation and superradiance is presented. We show that, although both phenomenons involve negative energy densities, there are two significant differences between them., Comment: Figure 2 in the version published in Phys Lett A is corrected in the arxiv version

The propagation of electromagnetic plane waves with negative phase velocity (NPV) is considered in Schwarzschild-(anti-)de Sitter spacetime. It is demonstrated that NPV propagation occurs in Schwarzschild-de Sitter spacetime at lower values of the cosmological constant than is the case for de Sitter spacetime. Furthermore, we report that neither is NPV propagation observed in Schwarzschild-anti-de Sitter spacetime, nor is it possible outside the event horizon of a Schwarzschild blackhole., Comment: Typographical error in eq (34) of EPL version is corrected in arxiv version. Europhysics Letters (accepted for publication)

We report on the occurrence of negative-phase-velocity (NPV) planewave propagation in the ergosphere of a rotating black hole. By implementing the Kerr metric, it is demonstrated that regions of NPV propagation are concentrated at the equator of the ergosphere, while NPV propagation is less common towards the polar regions. Increasing the angular velocity of the black hole exaggerates the NPV concentration at the equator. NPV propagation is not observed outside the stationary limit surface., Comment: Typographical error in eq (51) of NJP version is corrected in arxiv version

Propagation of electromagnetic plane waves in some directions in gravitationally affected vacuum over limited ranges of spacetime can be such that the phase velocity vector casts a negative projection on the time-averaged Poynting vector. This conclusion suggests, inter alia, gravitationally assisted negative refraction by vacuum., Comment: 6 pages

Examining the propagation of electromagnetic plane waves with the wavevector directed in opposition to the time-averaged Poynting vector in cosmological spacetime with piecewise uniform metric, we show that such negative-phase-velocity (NPV) propagation is possible in certain de Sitter spacetimes but not in anti-de Sitter spacetimes. This difference suggests the possibility of an optical/electromagnetic experiment to discern the cosmological constant of a four-dimensional universe stemming from a five-dimensional brane universe.

Examining the propagation of electromagnetic plane waves with the wavevector directed in opposition to the time-averaged Poynting vector in cosmological spacetime with piecewise uniform metric, we show that such negative-phase-velocity (NPV) propagation is possible in certain de Sitter spacetimes but not in anti-de Sitter spacetimes. This difference suggests the possibility of an optical/electromagnetic experiment to discern the cosmological constant of a four-dimensional universe stemming from a five-dimensional brane universe.

Examining the propagation of electromagnetic plane waves with the wavevector directed in opposition to the time-averaged Poynting vector in cosmological spacetime with piecewise uniform metric, we show that such negative-phase-velocity (NPV) propagation is possible in certain de Sitter spacetimes but not in anti-de Sitter spacetimes. This difference suggests the possibility of an optical/electromagnetic experiment to discern the cosmological constant of a four-dimensional universe stemming from a five-dimensional brane universe.

Propagation of electromagnetic plane waves in some directions in gravitationally affected vacuum over limited ranges of spacetime can be such that the phase velocity vector casts a negative projection on the time-averaged Poynting vector. This conclusion suggests, inter alia, gravitationally assisted negative refraction by vacuum., Comment: 6 pages

Developments that took place in the area of sculptured-thin-film technology after Bianisotropic' 98 are reviewed here. Devices addressed include: optical filters of various kinds, laser mirrors, gas concentration sensors, optical interconnects, interlayer dielectrics, and biosensors. Pulse bleeding is related to the circular Bragg phenomenon in chiral sculptured thin films. Acoustic research is also identified., Presented at Intl. Conference on Electromagnetics of Complex Media (8th), Lisbon, PT, 27-29 Sep 2000, p169-174. This article is from ADA398724 International Conference on Electromagnetics of Complex Media (8th), Held in Lisbon, Portugal on 27-29 September 2000. Bianisotropics 2000

In this two-part paper, a novel scheme of sensor-based on-line cutting tool flank wear estimation, called fractal estimation is developed, implemented and evaluated. This paradigm is unique in the sense that we extract fractal properties of sensor signals. The metric invariants of the sensor signals called fractal dimensions are related to the instantaneous flank wear using a recurrent neural network to implement a fractal estimator. The performance of the fractal estimator, evaluated using actual experimental data, establishes this scheme as a viable flank wear estimation paradigm. This methodology is general enough to be applied to many classes of estimation problems related to several manufacturing processes. We have developed the necessary theoretical formalisms and obtained implementation experiences through the research on tool wear monitoring in turning. The feature extraction methods used in this work are vital to the image analysis research and form the foundation for our future work. In this first part, theoretical foundations leading to the development of the fractal estimator are presented. New schemes of wavelet transform-based signal separation and fractal dimensions based feature extraction are described in detail.

Part 1 of this paper describes the theoretical foundations of fractal estimator development. The implementation aspects of the fractal estimator for online tool wear estimation in the turning process is described in this part. The results show that this paradigm can be successfully used for real time quality control in manufacturing.