Linear friction welding of Ti6Al4V: experiments and modelling

Linear friction welding of the Ti6Al4V alloy is studied. A new definition of the energy input rate is proposed, based on an integration over time of the in-plane force and velocity; a strong correlation with the upset rate is then found. The effective friction coefficient is estimated to be 0·5±0·1 for varying frequencies and amplitudes, with only a weak dependence on the processing conditions displayed. A model is proposed that accounts for both the conditioning and equilibrium stages of the process, which is shown to be in good agreement with the experimental data. The model is used to study the mechanism by which the flash is formed. A criterion is proposed by which the rippled nature of its morphology can be predicted.     

LEICA: a low energy ion composition analyzer for the study of solarand magnetospheric heavy ions

The SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) LEICA instrument is designed to measure ~0.5-5-MeV/nucleon solar and magnetospheric ions over the range from He-Ni. The instrument is a time-of-flight (TOF) mass spectrometer, which measures particle TOF over an ~0.5-m path and the residual energy deposited in an array of Si solid state detectors. Large-area microchannel plates are used, resulting in a large geometrical factor for the instrument (0.6 cm² sr), which is essential for accurate compositional measurements in small solar flares and in studies of precipitating magnetospheric heavy ions     

Analogues of capsaicin with agonist activity as novel analgesic agents: structure-activity studies. 4. Potent, orally active analgesics

Structural features of three regions of the capsaicin molecule necessary for agonist properties were delineated by a previously reported modular approach. These in vitro agonist effects were shown to correlate with analgesic potency in rodent models. Combination of optimal structural features from each of these regions of the capsaicin molecule have led to highly potent agonists (eg., 1b). Evaluation in vivo established that 1b had analgesic properties but poor oral activity, short duration of action, and excitatory side effects which precluded further development of this compound. Preliminary metabolism studies had shown that the phenol moiety of 1b was rapidly glucuronidated in vivo, providing a possible explanation for the poor pharmacokinetic profile. Subsequent specific modification of the phenol group led to compounds 2a-j, which retained in vitro potency. The in vivo profiles of two representatives of this series, 2a,h, were much improved over the "parent" phenol series, and they are candidates for development as analgesic agents.     

Analogues of capsaicin with agonist activity as novel analgesic agents; structure-activity studies. 3. The hydrophobic side-chain "C-region"

Structural variants of the hydrophobic side chain ("C region") of the capsaicin molecule have been incorporated into a series of vanillylamides and vanillylthioureas. These compounds have been tested in an in vitro assay for agonism (45Ca2+ influx into dorsal root ganglia neurones), previously shown to be predictive of analgesic activity. The results of this study have established the requirement for a hydrophobic substituent of limited size (molar refractivity, MR, < 55) in order to obtain high potency. Combination of the information gained here about the "C-region" of the capsaicin molecule with the studies described in the preceding two papers provides a rational basis for the design of compounds of increased potency.     

Effect of the amount of concentrate offered in an automated milking system on dry matter intake,milk yield,milk composition,ruminal digestion,and behavior of primiparous Holstein cows fed isocaloric diets

The objective of this study was to determine if the quantity of concentrate provided in an automated milking system (AMS) affects dry matter intake (DMI), attendance to the AMS, milk and milk component yield, feeding behavior, cow activity, and ruminal fermentation of lactating dairy cows fed isocaloric diets. Eight ruminally cannulated primiparous Holstein cows were used in a replicated 4 × 4 Latin square design with 28-d periods. Cows were housed in a freestall facility with a guided-traffic (feed-first) flow barn design. Treatments included 0.5, 2.0, 3.5, or 5.0 kg/d of dry matter of pellet in the AMS with an equivalent reduction of the same pellet in the partial mixed ration (PMR). Days 21 to 24 of each treatment period were used for DMI, milking performance (visits, yield, and composition), behavior, and ruminal pH determination, and d 25 to 28 were used for ruminal short-chain fatty acid and ammonia concentrations as well as total-tract digestibility. As imposed, consumption of AMS pellet linearly increased, equating to 0.50, 2.00, 3.49, and 4.93 kg of dry matter/d for the 0.5, 2.0, 3.5, and 5.0 kg/d treatments, respectively. Correspondingly, the standard deviation in AMS pellet intake among days linearly increased from 0.06 to 0.85 kg of dry matter/d as the quantity of concentrate in the AMS increased from 0.5 to 5.0 kg. The PMR DMI decreased linearly with increasing AMS concentrate allocation, but total DMI (PMR + AMS) was not affected (25.3 kg/d). As the AMS concentrate allocation increased, the selection against particles retained on an 18-mm sieve linearly increased and selection against particles retained on the pan decreased. Milking frequency (3.22 milkings/d), milk yield (37.5 kg/d), milk fat yield (1.43 kg/d), and milk protein yield (1.22 kg/d) were not affected; however, milk urea nitrogen concentration decreased linearly with increasing AMS concentrate. Ruminal pH averaged 6.18 and was not affected by AMS concentrate. Total ruminal short-chain fatty acid concentration was greatest when 3.5 kg of concentrate was allocated in the AMS and ruminal ammonia decreased linearly with increasing AMS concentrate. Time spent lying, the number of lying bouts, and average bout duration were not affected by treatment. These data indicate that increasing the quantity of concentrate in the AMS increases daily variability in AMS concentrate intake while decreasing PMR intake without affecting voluntary visits to the AMS and milk or milk component yield. As such, under isocaloric dietary settings, increasing the supply of pellet in the AMS is not likely to affect voluntary visits to the AMS, milk and milk component yields, or ruminal fermentation.     

An experimental analysis of DCT-based approaches for fine-grained multiresolution video

In the future, video-streaming systems will have to support adaptation over an extremely large range of display requirements (e.g., 90×60 to 1920×1080). This paper presents the architectural trade-offs of bandwidth efficiency, computational cost, and storage cost to support fine-grained multiresolution video over a large set of resolutions. While several techniques have been proposed, they have focused mainly on limited spatial resolution adaptation. In this paper, we examine the ability of current techniques to support wide-range spatial resolution adaptation. Based upon experiments with real video, we propose an architecture that can support wide-range adaptation efficiently. Our results indicate that multiple encodings with limited spatial adaptation from each encoding provide good trade-offs between efficient coding and the ability to adapt the stream to various resolutions. Jie Huang received her BS in computer and communications and MS in computer science from Beijing University of Posts and Telecommunications, Beijing, China, in 1992 and 1995 respectively, where she was an assistant professor from 1995 to 1999. Since 1999, she has been pursuing her PhD at OGI school of Science and Engineering at Oregon Health and Science University (from 1999 to 2004) and Portland State University (since 2004). Her research interests include multimedia networking and software engineering. Wu-chi Feng received his Ph.D. in Computer Science and Engineering from the University of Michigan in 1996. ~His research interests include multimedia systems, video-based sensor networking technologies, and networking. ~He currently serves as an Editor for the Springer-ACM Multimedia Systems Journal. ~He also serves on the national Orion Cyberinfrastructure Advisory committee. Jonathan Walpole received his Ph.D. degree in Computer Science from Lancaster University, UK. He is a Professor in the Computer Science Department at Portland State University. Prior to joining PSU he was a Professor and Director of the Systems Software Laboratory at the OGI School of Science and Engineering at Oregon Health & Science University. His research interests are in operating systems, networking, distributed systems and multimedia computing. He has pioneered research in adaptive resource management and the integration of application and system-level quality of service management. He has also done leading edge research on dynamic specialization for enhanced performance, survivability and evolvability of large software systems. His research on distributed multimedia systems began in 1988, and in the early 1990s he lead the development of one of the first QoS-adaptive Internet streaming video players.     

Gaussian patterned contacts for improved beam stability of1.55-μm tapered lasers

A Gaussian lateral current-injection profile is approximated by a quasi-random pattern of electrically conducting and insulating regions. This pattern is used for the p-type contact in a laser with a 2.1-mm-long tapered gain region and operating near 1.55-μm wavelength. Lasers with improved stable single lateral modes are obtained with Strehl ratios up to 0.85 for current up to 4.0 A and output power over 1.0 W. Power over 0.5 W can be coupled into a single-mode optical fiber with a cylindrical microlens attached to the output facet to remove the astigmatism of the laser     

Efficacy of gene testing for von Hippel-Lindau disease

OBJECTIVE: To determine the efficacy of genetic testing of individuals presenting with features possibly indicative of von Hippel-Lindau (VHL) disease, regardless of other relevant family and clinical details. SETTING AND PARTICIPANTS: Between September 1994 and December 1997, 16 unrelated individuals were referred to Genetic Services of Western Australia by local clinicians and by similar genetic services in other States, for VHL gene mutation analysis because of clinical manifestations suggestive of the diagnosis. METHODS: The subjects were investigated by screening for mutations in the polymerase chain reaction products of the three VHL gene exons using single-stranded conformational polymorphism analysis (SSCP). If no mutations were detected the exons were sequenced, and if no variations were found DNA was examined by Southern analysis for germinal rearrangements. RESULTS: Mutations in the VHL gene were detected in eight of 16 individuals (50%), including 3 individuals with no family history suggestive of VHL disease. Five mutations were detected by SSCP, two by gene sequencing and one by Southern analysis. Each mutation occurred only in a single family and three had not been previously reported. CONCLUSION: Genetic screening of individuals presenting with clinical features suggestive of VHL facilitates confirmation of the diagnosis, accurate genetic counselling and surveillance of at-risk family members. The necessity for costly and time-consuming screening programs can be reduced and screening directed at those carrying the mutation. Our low stringency criteria are justified for screening for VHL mutations.     

GaInAsSb-AlGaAsSb tapered lasers emitting at 2.05 μm with 0.6-Wdiffraction-limited power

Tapered lasers fabricated from a GaInAsSb-AlGaAsSb single-quantum-well structure are reported. The laser structure, grown by molecular beam epitaxy, has broad-stripe pulsed threshold current densities as low as 50 A/cm² at room temperature. Tapered lasers have exhibited diffraction-limited continuous-wave output power up to 600 mW     

Simple compact diode-laser/microlens packaging

A technique has been demonstrated in which the precisely polished substrate of a microlens is directly attached to the front face of a diode laser and heatsink to form a compact stable package. An experimental package using mass-transported GaP spherical microlenses and InGaAs-AlGaAs ridge-waveguide lasers (0.98-μm wavelength) showed a well-collimated beam with a near diffraction-limited 0.7° divergence. The high-index microlens and the favorable lens configuration showed high tolerance for alignment errors in the optical-path-difference and Strehl-ratio calculations