Optical phase change at the interface between mica and thin silver film

We describe a simple experiment which allows unequivocal determination of optical phase change upon reflection of light at the mica-silver interface. While the physical origin of such a phase change at the dielectric-metal interface is well understood to lie in absorption of electromagnetic energy by the metal, inconsistency and ambiguity has persisted as to what its sign and magnitude should be in the field of thin film optics. Most commonly, it has been assigned to be negative for mathematical convenience or just arbitrarily. Our finding shows that with the convention exp(-iωt) for time dependence of the electromagnetic wave, the phase change at the interface between mica and the thin silver film is necessarily positive and its magnitude falls between π and 3π/2 for silver thicknesses down to nanometres. This gives a physically reasonable correspondence to an increased equivalent thickness of the dielectric material, and it clarifies the assignment of interference orders in the harmonic series in a spectrum.

Interface slip control for CFRP-concrete composite beams

Carbon fibre reinforced polymer (CFRP) has been used frequently to retrofit concrete structures. Strengthening efficiency is related to the CFRP application process and the characteristics of the bonding agent. In this paper the mechanism of interface shear behaviour in CFRP to concrete beams is discussed considering previous test observations and mathematical models. This paper then discusses the consequences of introducing interface slip which reduces the integrity of the composite section, however improve ductility and delay debonding failure. The paper suggests that using softer bonding agent as well as setting limits on the interface slip could ensure acceptable serviceability and ductile behaviour.

User-centered design and evaluation of an interactive visual-haptic-auditory interface : a user study on assembly

Utilizing user-centred system design and evaluation method has become an increasingly important tool to foster better usability in the field of virtual environments (VEs). In recent years, although it is still the norm that designers and developers are concerning the technological advancement and striving for designing impressive multimodal multisensory interfaces, more and more awareness are aroused among the development team that in order to produce usable and useful interfaces, it is essential to have users in mind during design and validate a new design from users' perspective. In this paper, we describe a user study carried out to validate a newly developed haptically enabled virtual training system. By taking consideration of the complexity of individual differences on human performance, adoption and acceptance of haptic and audio-visual I/O devices, we address how well users learn, perform, adapt to and perceive object assembly training. We also explore user experience and interaction with the system, and discuss how multisensory feedback affects user performance, perception and acceptance. At last, we discuss how to better design VEs that enhance users perception, their interaction and motor activity.

Air pressure and wind velocity - modelling ember attack within the urban-rural interface

As population change places pressure on expanding regional and metropolitan urban boundaries, so the threat of bushfire at the rural/urban interface increases. This paper presents a range of 2D and 3D 1:40 and full scale modelling investigations. Various relationships are explored between the urban and rural interface with respect to: air pressure; changes in wind pattern; vectorial velocity; and the deposition of hot ash and firebrand deposits around single story building forms, both as standalone and within an orthogonal array and cul-de-sac relationships.

An embedded suggestive interface for making home videos

This paper describes a novel suggestive interface embedded in a smart camera prototype aimed at aiding home movie makers. We focus on the problem of generating shot capture suggestions suitable to the user's filming context, intended audience and style, and formulate a novel aesthetic measure by which to judge proposed suggestions. Tight coupling between media and software allows the aesthetic measure to be sensitive to previous footage captures, including those taken without the system's prompting, in a manner allowing flexible, end-to-end migration of the authoring task from user to machine. An approximate method is used to find timely, near-optimal solutions to the aesthetic measure. Qualitative evaluation in the form of a user study shows it to be a promising approach to the flexible home movie authoring context.

Microbial lipases : at the interface of aqueous and non-aqueous media: a review

In recent times, biotechnological applications of microbial lipases in synthesis of many organic molecules have rapidly increased in non-aqueous media. Microbial lipases are the working horses' in biocatalysis and have been extensively studied when their exceptionally high stability in non-aqueous media has been discovered. Stability of lipases in organic solvents makes them commercially feasibile in the enzymatic esterification reactions. Their stability is affected by temperature, reaction medium, water concentration and by the biocatalyst's preparation. An optimization process for ester synthesis from pilot scale to industrial scale in the reaction medium is discussed. The water released during the esterification process can be controlled over a wide range and has a profound effect on the activity of the lipases. Approaches to lipase catalysis like protein engineering, directed evolution and metagenome approach were studied. This review reports the recent development in the field of non-aqueous microbial lipase catalysis and factors controlling the esterification/transesterification processes in organic media.

Design, development, and evaluation of a pinch-grasp haptic interface

Interaction with virtual or teleoperated environments requires contact with objects on a multipoint level. We describe the design of a pinch--grasp hand interface device for use as a grasping mechanism to complement haptic interfaces. To preserve a suitable level of transparency for human--computer interaction, this novel interface is designed for high-resolution contact forces, while centered around a lightweight structure. This functionality renders the device scalable and adaptable to a wide range of haptic interface structures and force level requirements. We present an optimal configuration for a pinch--grasp interface, which produces bidirectional forces to an operator's fingers and a rotational force to the wrist through a cable drive system. The device is characterized for use on a commercial haptic interface through demonstration of sustained peak performance and also workspace utilization. The dynamic performance of the pinch--grasp interface is experimentally determined, and the frequency response is identified to illustrate its contact force resolution.

Desiring the interface : introducing technoculture

In introducing the eight papers that constitute the theme of technoculture for this issue, I suggest that the diversity in responses to and understandings of the term 'technoculture' is not a weakness but a strength. The diffuse results of technocultural studies reflect the desires for relevance, generality and creation with intellectual discourse which, in technocultural limes. enable or require diverse subject mailer to be labelled 'technoculture'.

Effects of tool positioning on joint interface microstructure and fracture strength of friction stir lap Al-to-steel welds

Friction stir lap welding (FSLW) experiments have been conducted to study the effects of tool positioning on microstructures formed in the Al-to-steel interface region and on joint strength, defined as maximum applied force over the width (F m/w s) of the test sample, of the welds. Various pin positioning and speed conditions were used in the FSLW experiments followed by microstructure examination on the interface regions and tensile-shear testing on the welds, including an examination on crack propagation in mixed stir zone. It was found that when the pin was close to the bottom steel piece, Al-to-steel reaction occurred resulting in intermetallic outbursts formed along the interface. This represents the case of incomplete metallurgical joint. When the pin was lowered to just reach the steel, a thin and continued interface intermetallic layer formed. Evidences and consideration on growth kinetics have suggested that the layer could only remain thin (≤2.5 μm) during FSLW. This layer could bear a high load during tensile-shear testing and the adjacent aluminium deformed and fractured instead. The resulting F m/w s was high. When the pin penetrated to steel, F m/w s reduced due to brittle fracture being dominant inside mixed stir zone. Evidences have shown that the amount of penetration and speed condition during FSLW do not have large effects on F m/w s.

Insight into reactions and interface between boron nitride nanotube and aluminium

Nature and mechanism of interfacial reactions between boron nitride nanotubes (BNNTs) and aluminum matrix at high temperature (650 °C) are studied using high-resolution transmission electron microscopy (HRTEM). This study analyzes the feasibility of the use of BNNTs as reinforcement in aluminum matrix composites for structural application, for which interface plays a critical role. Thermodynamic comparison of aluminum (Al)-BNNT with analogous Al-carbon nanotube (Al-CNT) system reveals lesser amount of reaction in the former. Experimental observation also reveals thin (~7 nm) reaction-product formation at Al-BNNT interface even after 120 min of exposure at 650 °C. The spatial distribution of the reaction-product species at the interface is governed by the competitive diffusion of N, Al, and B. Morphology of the reaction products are influenced by their orientation relationship with BNNT walls. A theoretical prediction on Al-BNNT interface in macroscale composite suggests the formation of strong bond between the matrix and reinforcement phase.