Dual-wavelength cascaded Raman fibre laser

Dual-wavelength lasing at 1480 and 1500 nm has been demonstrated from a cascaded Raman fibre laser with a WDM coupler and two pairs of Bragg gratings. Intensity-adjustable, wavelength-tunable laser operation was achieved by tensile stress wavelength tuning of the gratings     

Motivations for Open Source Project Participation and Decisions of Software Developers

We provide a rationale for open source project participation by studying the decision problems of the software programmers, whose types are different in terms of ability and intrinsic motivation. We find that motivations, both intrinsic and extrinsic, and the ability level positively affect the optimal level of effort exerted by the programmers in the open source project. In the commercial project, the programmers with higher ability exert much effort although their high level of effort is not compensated properly. Thus, the open source project might be more likely to attract capable and motivated programmers than the commercial project.     

Humanoid robots as “The Cultural Other”: are we able to love our creations?

Robot enthusiasts envision robots will become a “race unto themselves” as they cohabit with the humankind one day. Profound questions arise surrounding one of the major areas of research in the contemporary world—that concerning artificial intelligence. Fascination and anxiety that androids impose upon us hinges on how we come to conceive of the “Cultural Other.” Applying the notion of the “other” in multicultural research process, we will explore how the “Other” has been used to illustrate values and theories about robots, as a mirror for the self. In this paper, we focus on the social, cultural, and religious implications of humans’ attitudes toward relationships between humans with robots. Six major views on humanoid robots are proposed: (1) robots as the “Frightening Other,” (2) robots as the “Subhuman Other,” (3) robots as the “Human Substitute,” (4) robots as the “Sentient Other,” (5) robots as the “Divine Other,” and (6) robots as the “Co-evolutionary Path to Immortality.” The likely and preferable scenario is the last one, which is compatible with an optimistic posthuman world in our evolutionary future. We imagine whether humans will meet the challenge of loving all living and non-living beings (including mechanical entities) might be the key to the co-evolution of both species and the ultimate happiness.     

Integrity and cell-monolayer permeability of chitosan nanoparticles in simulated gastrointestinal fluids

The objective of this study was to assess the integrity and intestinal permeability of chitosan nanoparticles (CNPs) in simulated gastrointestinal fluids (SGIF). The cell-associated and transported chitosan was quantified and visualized after incubation of the CNPs with Caco-2 cell monolayer with/without SGIF treatment. In order to establish the role of proteins in the SGIF, CNPs were incubated with 4 proteins having different isoelectric points (pI). CNPs incubated with the fluids did not attach to the cell monolayer in contrast to the intact CNPs. Negatively-charged protein formed the complex with CNPs leading to particle size increase, but protected CNPs from disintegration. In contrary, positively-charged protein interacted with cross-linker causing disintegration of CNPs. CNPs incubated with the fluids did not attach to the cell monolayer in contrast to the intact CNPs. The results suggested that the surface charges of CNPs and proteins play a critical role in structural changes of CNPs in biological environment.     

Bias-error reduction in nanometer resolution microscopic motion tracking vision systems

Microscopic Motion Tracking Systems utilize sub-pixel algorithms to achieve close to nanometer precision motion measurement. This paper characterizes the bias-error of template matching image registration techniques which are commonly used to achieve this level of sub-pixel accuracy. An accurate functional expression for such bias error is derived, which shows how the error depends on image content. Furthermore, this expression is directly utilized in a bias reduction scheme that is shown to significantly reduce the bias error. The newly derived expressions and reduction schemes for bias are applied to a Microscopic Vision System that measures micro-object motion with close to nanometer resolution.     

Supersonic Nozzle Flow Simulations for Particle Coating Applications: Effects of Shockwaves,Nozzle Geometry,Ambient Pressure,and Substrate Location upon Flow Characteristics

Characteristics of supersonic flow are examined with specific regard to nano-particle thin-film coating. Effects of shockwaves, nozzle geometry, chamber pressure, and substrate location were studied computationally. Shockwaves are minimized to reduce fluctuations in flow properties at the discontinuities across diamond shock structures. Nozzle geometry was adjusted to ensure optimal expansion (i.e., P _exit = P _ambient), where shock formation was significantly reduced and flow kinetic energy maximized. When the ambient pressure was reduced from 1 to 0.01316 bar, the nozzle’s diverging angle must be increased to yield the optimum condition of minimized adversed effects. Beyond some critical distance, substrate location did not seem to be a sensitive parameter on flow characteristics when P _amb = 0.01316 bar; however, overly close proximity to the nozzle exit caused flow disturbances inside the nozzle, thereby adversely affecting coating gas flow.     

Structural dynamic displacement vision system using digital image processing

This study introduces dynamic displacement vision system (DDVS), which is applicable for imaging unapproachable structures using a hand-held digital video camcorder and is more economical than the existing contact and contactless measurement methods of dynamic displacement and deformation. This proposed DDVS method is applied to the Region of Interest (ROI) resizing and coefficient updating at each time step to improve the accuracy of the measurement from the digital image. Thus, after evaluating the algorithms conducted in this study by the static and dynamic verification, the measurement's usability by calculating the dynamic displacement of the masonry specimen, and the two-story steel frame specimen is evaluated under uniaxial seismic loading. The algorithm of the proposed method in this study, despite the relatively low resolution during frozen, slow, and seismic motions, has precision and usability that can replace the existing displacement transducer. Moreover, the method can be effectively applied to even fast behavior for multi-measurement positions like the seismic simulation test using large scale specimen. DDVS, using the consecutive images of the structures with an economic, hand-held digital video camcorder is a more economical displacement sensing concept than the existing contact and contactless measurement methods.     

Application of laser-induced breakdown spectroscopy for detecting leakage of boric acid

Recently, many studies have been conducted on developing on-line leak detection techniques in the reactor vessel head of nuclear power plants. One of them, laser-induced breakdown spectroscopy (LIBS), an effective technique of leak detection, which is a kind of atomic emission spectroscopy that uses a highly energetic laser pulse as the excitation source, has been of interest due to the fast and reliable identification of chemical elements for the precipitates formed by the leakage of cooling water containing boric acid. Experimental setup and tests were performed for the boric acid precipitates formed on the steel for various conditions with a Q-switched 532 nm Nd:YAG laser, optical lenses, an Echelle spectrograph and an intensified charge-coupled device detector. The LIBS system could be applied to obtain a spectral line (～249. 2 nm) corresponding to the atomic boron emission line for the precipitates of boric acid formed on low alloy steels, SA508 and SA533, as a substrate. The LIBS technique based on characterizing boric acid deposits might be used for detecting the leakage of cooling water in reactor vessel head of nuclear power plants.     

Kernel TIF method for effective material removal control in rotating pitch tool-based optical figuring

While opticians have used pitch tools for superb surface finishing, their poor controllability in material removal and associated lengthy tooling overhead have been well known in optics fabrication communities. We report a new computational technique called kernel tool influence function (KTIF) that can bring higher predictability to pitch tool-based material removal. The term ??kernel?? is defined as the ratio of experimental to simulated removal depth, therefore transforming the material removal coefficient of Preston??s equation to a removal scaling function at each point on the tool surface. This approach offers a unique inherent control feature incorporating ??real-life shop floor effects associated with pitch tool polishing variables?? into the tool influence functions without the need for theoretical expressions for the effects of individual variables on material removal behavior. Using a modified Draper-type polishing machine and a rotating pitch tool, we first generated kernel TIFs with zero stroke and used them for simulation and trial experiments of extended TIFs with variable tool strokes. The results show that the root mean square (rms) TIF profile differences between the prediction and experiments are in the range of 11 to 29?nm for conventional TIF and 7 to 15?nm for the KTIF. We then generated conventional TIF and KTIF database sets and applied them to surface figuring simulations. The results confirm that the kernel TIF has superior performance to the conventional TIF in controlling the material removal for correction of the chosen surface error.