Fabrication of high-aspect-ratio microstructures on planar andnonplanar surfaces using a modified LIGA process

Large surface areas (tens of square centimeters to square meters) covered with high-aspect-ratio microstructures (HARMs) have potential applications in a wide range of fields including heat transfer, adaptive aerodynamics, acoustics, catalysts, seal and bearing design, and composite materials. HARMs are typically hundreds of micrometers in height, with widths ranging from a few micrometers to tens of micrometers, and they can be manufactured from a variety of materials such as metals, polymers, and ceramics. Three of the barriers to extensive use of large HARM-covered surfaces are cost, nonplanarity of typical surfaces, and adhesion of the microstructures to the surface. A starting point for inexpensive reproduction of large arrays of HARMs is the plastic molding step of the LIGA micromanufacturing process. In order to address the latter two problems, the standard LIGA process was modified/extended. Free-standing polymer sheets, perforated with a pattern of high-aspect-ratio throughholes, were clamped to conductive substrates. The sheets provide a template for electrodeposition of nickel microstructures onto the target surface. This process makes it economically feasible to electroform metal microstructures directly onto large planar and nonplanar metal surfaces (cylinders)     

<Emphasis Type="Italic">A Midsummer Night’s Dream</Emphasis> (with flying robots)

Seven flying robot “fairies” joined human actors in the Texas A&;M production of William Shakespeare’s A Midsummer Night’s Dream. The production was a collaboration between the departments of Computer Science and Engineering, Electrical and Computer Engineering, and Theater Arts. The collaboration was motivated by two assertions. First, that the performing arts have principles for creating believable agents that will transfer to robots. Second, the theater is a natural testbed for evaluating the response of untrained human groups (both actors and the audience) to robots interacting with humans in shared spaces, i.e., were believable agents created? The production used two types of unmanned aerial vehicles, an AirRobot 100-b quadrotor platform about the size of a large pizza pan, and six E-flite Blade MCX palm-sized toy helicopters. The robots were used as alter egos for fairies in the play; the robots did not replace any actors, instead they were paired with them. The insertion of robots into the production was not widely advertised so the audience was the typical theatergoing demographic, not one consisting of people solely interested technology. The use of radio-controlled unmanned aerial vehicles provides insights into what types of autonomy are needed to create appropriate affective interactions with untrained human groups. The observations from the four weeks of practice and eight performances contribute (1) a taxonomy and methods for creating affect exchanges between robots and untrained human groups, (2) the importance of improvisation within robot theater, (3) insights into how untrained human groups form expectations about robots, and (4) awareness of the importance of safety and reliability as a design constraint for public engagement with robot platforms. The taxonomy captures that apparent affect can be created without explicit affective behaviors by the robot, but requires talented actors to convey the situation or express reactions. The audience’s response to robot crashes was a function of whether they had the opportunity to observe how the actors reacted to robot crashes on stage, suggesting that pre-existing expectations must be taken into account in the design of autonomy. Furthermore, it appears that the public expect robots to be more reliable (an expectation of consumer product hardening) and safe (an expectation from product liability) than the current capabilities and this may be a major challenge or even legal barrier for introducing robots into shared public spaces. These contributions are expected to inform design strategies for increasing public engagement with robot platforms through affect, and shows the value of arts-based approaches to public encounters with robots both for generating design strategies and for evaluation.     

Condensing heat transfer for R114/R12 mixtures on horizontal finned tubes

Two titanium tubes with external fins were tested in the horizontal orientation to determine heat transfer performance with R114, R12, and selected non-azeotropic mixtures of the two condensing on the outside surface. For the single-component situation, data were in excellent agreement with predictions from a modified Katz-Keller method, and little performance distinction was found between the tubes or between the pure refrigerants. All mixtures depressed performance below single-component levels, with even low second-component concentrations causing substantial degradation (up to 55% performance reduction for 5% R12). Gas chromatograph composition analyses of vapour from the condenser shell showed elevated concentrations of the more volatile component (R12), evidence that an added transport resistance contributed to the observed mixture performance reductions. If previously suggested benefits of mixtures in heat pump applications are to be realized, the associated condensers should be in a configuration so as to mitigate these performance penalties.     

The use of the portable ergonomic observation method (PEO) to monitor the sitting posture of schoolchildren in the classroom

Contrary to common belief, back pain amongst young people is a frequent phenomenon. Epidemiological studies have found high prevalence rates of back pain amongst schoolchildren. The investigation reported here aims to validate children's self-reporting and the observation of sitting postures to establish the intensity, duration and frequency of exposure in the classroom. The sitting postures of 18 children were recorded using three methods, the portable ergonomic observation method (PEO), video analysis and self-report. The three methods were compared. PEO was significantly correlated with video analysis of the sitting postures after development of the method. Self-report was not significantly correlated with video analysis of the sitting postures. Therefore PEO was selected as the main observation tool in further analysis of children's sitting posture in schools in South-East England as part of a large research programme investigating back pain amongst schoolchildren.     

Intangible benefits valuation in ERP projects

The development, implementation and ownership of information systems, especially large‐scale systems such as enterprise resource planning (ERP), has become progressively longer in duration and more cost intensive. As a result, IS managers are being required to justify projects financially based on their return. Historically, information systems have been difficult to quantify in monetary terms because of the intangible nature of many of the derived benefits, e.g. improved customer service. Using the case study methodology, this paper examines an attempt by a large computer manufacturer to incorporate intangibles into traditional cost–benefit analysis in an ERP project. The paper reviews the importance of intangibles, lists intangible benefits that are important in ERP projects and demonstrates the use of a scheme through which they can be incorporated into traditional evaluation techniques.     

Microfabrication of high aspect ratio Bi–Te alloy microposts and applications in micro-sized cooling probes

 High aspect ratio microposts of bismuth telluride alloy with heights of up to 500 μm and a diameter of 150 μm have been fabricated with the LIGA technique. This work is part of an on-going research effort to develop a microprobe based on the Peltier effect for highly localized temperature manipulation on the microscale. Bismuth telluride alloys were electrodeposited galvanostatically into microfeatures on a titanium substrate using an acidic solution containing Bi³⁺and HTeO^- ₂ ions in 1 mol/dm³ nitric acid (pH∼0). The Bi–Te alloy microposts were monophasic, had a polycrystalline structure, demonstrated excellent adhesion to the substrate, and good mechanical strength. The chemical composition of the microposts was dependent on the electrolyte composition of the deposition bath and the current density used in electroplating; by controlling these two factors either p- or n-type Bi–Te alloy microposts may be produced. This research demonstrates that the microfabrication of Peltier effect probes is feasible. Received: 29 July 1998/Accepted: 17 August 1998     

Event-Based Techniques to Debug an Object Request Broker

This work presents a debugging system built for the Object Request Broker (ORB) used in the construction of Solaris MC, a multicomputer OS. Even though it has been built and tested on a particular ORB, we believe similar ideas could be employed on other ORBs with similar structure and goals. The goal of this system is to provide a means to stress the ORB behavior in a controlled manner while logging the events occurred during its execution. The tool, called the Fault Injection and Event Logging Tool (FIELT) helps system programmers to find possible inconsistencies in the code by means of a post-mortem analysis of the collected trace data. The approach taken to design the event logging follows the event-driven techniques to monitorize distributed systems. Failures in the ORB are injected by software instrumentation and these injected failures are considered as special events. This allows us to reason about the correctness of the ORB in a broad sense, where its expected behavior includes to gracefully cope with failures. The number of potentially relevant events produced during the ORB execution is unmanageably high. There is, thus, a need to find a minimum subset of those events which, without losing relevant system behavior, allows us to infer its correctness (or lack of). We address this problem using a new model for ORB computations, assigning each event produced by the ORB to one of the high level objects it manages.     

Shadowbowl 2003 [simulated mass-casualty exercise]

On 25-26 January 2003, a simulated mass-casualty exercise called ShadowBowl was conducted. A mass-casualty incident is an event in which local response capabilities are overwhelmed, and outside resources must be integrated as rapidly as possible to mitigate the situation. This article provides an account of the event, observations, and suggestions for improvements from the CRASAR perspective. ShadowBowl consisted of two tests, the first of which was a simulated earthquake response on 25 January 2003 and the remainder of which was an exercise conducted in parallel with Super Bowl XXXVII, with personnel and equipment on site at Qualcomm Stadium in San Diego, California, and across the country, in case a terrorist attack occurred. Capabilities that were demonstrated and tested include environmental monitoring (using sensors to detect radiation, water quality, and fire) and chemical hazard mitigation. This exercise was significant because it exposed a number of issues in a realistic emergency scenario, and the findings from the exercise can help to improve readiness for the next real disaster. Important lessons learned from ShadowBowl include what failed unexpectedly, the difficulty involved in performing what would otherwise be considered mundane tasks, and the ideal configuration of a local command center for specialists trying to use data coming from robots in the field. These lessons encompass critical components of reachback: communications, human factors, and adherence to standards. This article discusses the impact of unexpected failures on communications and other equipment, errant expectations, and information standards (synchronization and data formats).