Measurement of pressures in the nucleus and within the annulus of the human spinal disc: due to extreme loading

Specially developed intervertebral and intradiscal pressure transducers are used to map the pressures in the nucleus pulposus and within the annulus fibrosus of the human spinal discs, to the point of fracture of the segmental units. The results show that for normal discs, pressures in the nucleus and in the annulus are linearly related to each other and to the applied compressive loads. Mechanical strains which develop around the periphery of the vertebral body are also linear with the applied compressive loads, when the partial vertebral column is loaded to the point of bony fracture. Failure of the intervertebral discs at the point of fracture occurred through the vertebral body endplates and the annulus fibrosus remained intact.     

Defining standard skies for Hong Kong

A CIE International Daylight Monitoring Programme (IDMP) general class station was established in 2000 at the Chinese University of Hong Kong. The station was upgraded to Research Class IDMP Station in April 2003. The study, which includes the sky luminance scan data collected from April 2003 to May 2005, firstly fits the data to the CIE Standard General Sky definitions, which consist of 15 luminance distributions for modeling the sky from the heavily overcast sky to cloudless clear sky. Then the paper proposes a reduced set of CIE general skies (and their probability of occurrence) to represent the sky conditions of Hong Kong. This reduced set will be known in this paper as “Hong Kong Representative Sky” (HKRS). Further, the paper evaluates the sensitivity of vertical sky component (VSC) to differences between the HKRS and the standard CIE Overcast Sky model. Comparing with observed data, it is demonstrated that the HKRS could give better results. A reduction in error of approximately 20–40% could be expected, depending on the orientation of a surface. Using the HKRS, building designers could better predict daylight availability of their design. Energy saving and more sustainable buildings might result.     

Effect of courtyard proportions on solar heat gain and energy requirement in the temperate climate of Rome

The present study focuses mainly on the effect of solar heat gain on the energy demand of courtyard building form with different proportions. Several methods can be employed to improve the building's utilization of solar heat gain. This includes using light colours for the external surfaces to reduce the solar radiation absorption in summer, using shading devices and improving the thermal properties of the external walls and roof. However, it is of great importance before using any of these methods to have the courtyard building's architectural design adapted to have full advantage of the available solar heat gain. Therefore, the main objective of the present examination was to find out to what extent the building's solar heat gain and consequently the energy requirements are influenced by the building's configurations. A computer Tool (IES) was used to carry out the investigation taking Rome as an empirical background to temperate climate. The results showed that the proportions of the courtyard building considerably influence the need for heating and cooling.     

The equilibrium orientation relationship between Pt and SrTiO3 and its implication on Pt films deposited by physical vapor phase deposition

The equilibrium orientation of Pt in contact with (100)-SrTiO₃, at 1050 °C and in an Ar/2 % O₂ environment, was determined by solid-state dewetting of continuous Pt films on single crystal SrTiO₃ substrates. Given the similar lattice parameters between Pt and SrTiO₃, a simple cube-on-cube orientation relationship was expected to form at equilibrium. However, only a preferred orientation of Pt {111} parallel to the SrTiO₃ (100) surface formed, without a low-index orientation relationship. It was found that reconstruction of the SrTiO₃ surface (a complexion) was responsible for the Pt particle texture. The equilibrium crystal shape of the Pt particles was analyzed and it was found to contain the following facets: {111}, {100}, {110}, and {113}.     

Sequentially consistent versus linearizable counting networks

We compare the impact of timing conditions on implementing sequentially consistent and linearizable counters using (uniform) counting networks in distributed systems. For counting problems in application domains which do not require linearizability but will run correctly if only sequential consistency is provided, the results of our investigation, and their potential payoffs, are threefold: First, we show that sequential consistency and linearizability cannot be distinguished by the timing conditions previously considered in the context of counting networks; thus, in contexts where these constraints apply, it is possible to rely on the stronger semantics of linearizability, which simplifies proofs and enhances compositionality. Second, we identify local timing conditions that support sequential consistency but not linearizability; thus, we suggest weaker, easily implementable timing conditions that are likely to be sufficient in many applications. Third, we show that any kind of synchronization that is too weak to support even sequential consistency may violate it significantly for some counting networks; hence, we identify timing conditions that are to be totally ruled out for specific applications that rely critically on either sequential consistency or linearizability. A preliminary version of this work appears in the Proceedings of the 18th annual ACM symposium on principles of distributed computing (PODC 1999), pp. 133–142, May 1999. This work has been partially supported by the IST Program of the European Union under projects DELIS (contract number 001907) and AEOLUS (contract number 15964).     

Refactoring techniques for aggressive object inlining in Java applications

Object Inlining (OI) is a known optimization in object oriented programming in which referenced objects of class B are inlined into their referencing objects of class A by making all fields and methods of class B part of class A. The optimization saves all the new operations of B type objects from class A and at the same time replaces all indirect accesses, from A to fields of B, by direct accesses. To the best of our knowledge, in-spite of the significant performance potential of the OI optimization, reported performance measurements were relatively moderate. This is because an aggressive OI optimization requires complex analysis and code transformations to overcome problems like multiple references to the inlinable object, object references that escape their object scope, etc.     

Knowledge in shared memory systems

Summary We study the relation between knowledge and space. That is, we analyze how much shared memory space is needed in order to learn certain kinds of facts. Such results are useful tools for reasoning about shared memory systems. In addition we generalize a known impossibility result, and show that results about how knowledge can be gained and lost in message passing systems also hold for shared memory systems. Michael Merritt received a B.S. degree in Philosophy and in Computer Science from Yale College in 1978, the M.S. and Ph.D. degrees in Information and Computer Science in 1980 and 1983, respectively, from the Georgia Institute of Technology. Since 1983 he has been a member of technical staff at AT & T Bell Laboratories, and has taught as an adjunct or visiting lecturer at Stevens Institute of Technology, Massachusetts Institute of Technology, and Columbia University. In 1989 he was program chair for the ACM Symposium on Principles of Distributed Computing. His research interests include distributed and concurrent computation, both algorithms and formal methods for verifying their correctness, cryptography, and security. He is an editor for Distributed Computing and for Information and Computation, recently co-authored a book on database concurrency control algorithms, and is a member of the ACM and of Computer Professionals for Social Responsibility. Gadi Taubenfeld received the B.A., M.Sc. and Ph.D. degrees in Computer Science from the Technion (Israel Institute of Technology), in 1982, 1984 and 1988, respectively. From 1988 to 1990 he was a research scientist at Yale University. Since 1991 he has been a member of technical staff at AT & T Bell Laboratories. His primary research interests are in concurrent and distributed computing.A preliminary version of this work appeared in the Proceedings of the Tenth Annual ACM Symposium on Principles of Distributed Computing, pages 189–200, Montreal, Canada, August 1991     

Microwave Detection of Stress-Induced Fatigue Cracks in Steel and Potential for Crack Opening Determination

Fatigue crack detection in metals is an important practical issue in many industries. In this paper the results of detecting fatigue cracks, using the dominant mode approach, employing flange-mounted, open-ended, rectangular waveguides at several microwave frequencies are presented. The goal of this investigation has been to demonstrate the capability of this approach for detecting stress-induced cracks under various static loads. In addition, a correlation between the features of the measured crack characteristic signals and crack opening has been sought. The results show that at all of the investigated frequencies, cracks from being nearly closed to having openings of up to 0.0508 mm are detected effectively. Furthermore, it is found that the interaction of the flange edge with a crack results in features that can be used to enhance crack detection robustness significantly (i.e., increased probability of detection). Several features associated with these measured crack characteristic signals are shown to correlate linearly with crack opening. Such simple correlations may then be used to estimate a crack opening closely after it has been detected using this approach. A complete discussion of the results is also provided in this paper.