The PHENIX Experiment at RHIC

The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

Human Resource Flexibility as a Mediating Variable Between High Performance Work Systems and Performance

Much of the human resource management literature has demonstrated the impact of high performance work systems (HPWS) on organizational performance. A new generation of studies is emerging in this literature that recommends the inclusion of mediating variables between HPWS and organizational performance. The increasing rate of dynamism in competitive environments suggests that measures of employee adaptability should be included as a mechanism that may explain the relevance of HPWS to firm competitiveness. On a sample of 226 Spanish firms, the study’s results confirm that HPWS influences performance through its impact on the firm’s human resource (HR) flexibility

High performance computing at Sandia National Labs

Sandia`s High Performance Computing Environment requires a hierarchy of resources ranging from desktop, to department, to centralized, and finally to very high-end corporate resources capable of teraflop performance linked via high-capacity Asynchronous Transfer Mode (ATM) networks. The mission of the Scientific Computing Systems Department is to provide the support infrastructure for an integrated corporate scientific computing environment that will meet Sandia`s needs in high-performance and midrange computing, network storage, operational support tools, and systems management. This paper describes current efforts at SNL/NM to expand and modernize centralized computing resources in support of this mission

Perfect Absorption of Sound by Rigidly-Backed High-Porous Materials

[EN] We present the conditions to observe perfect sound absorption by rigidly-backed layers of rigid-frame highporous materials. We theoretically analyze different configurations of increasing complexity: a single layer of high-porous material, a layer of high-porous material with an air gap (air plenum), and an optimized multilayer structure. First, we show that to obtain normal incidence perfect sound absorption at the first so-called quarterwavelength resonance of a single rigidly-backed high-porous layer, the thickness of the material is strongly related to its flow resistivity. In particular, perfect sound absorption is observed when the quarter-wavelength resonance is around the characteristic Biot frequency of the high-porous media. We found that the optimal thickness of the layer is 4.64 smaller than the perfectly absorbed wavelength when using one-parameter empirical models for the effective parameters of the high-porous material. Then, we analyze the behavior of the structure for oblique angles of incidence, showing that perfect sound absorption is also produced for other incident angles and frequencies. Second, an air gap is introduced between the high-porous layer and the rigid backing. The gap allows to produce perfect sound absorption for structures thicker than the optimal one and for media with large intrinsic losses, i.e., for materials with high flow resistivity. Finally, optimized multilayer structures are proposed, which present broadband and perfect sound absorption. The existence of perfect absorption is related to the impedance matching, which is produced when the intrinsic losses of the system exactly compensate the leakage of the structure due to its resonance. Thus, to observe perfect sound absorption, in addition to and material properties, the total thickness of any multilayered porous structure is constrained to its quarter-wavelength resonance because of the lack of deep-subwavelength resonance in the system.The authors acknowledge financial support from the Metaudible Project No. ANR-13-BS09-0003, co funded by ANR and FRAE. This article is based upon work from COST Action DENORMS CA 15125, supported by COST (European Cooperation in Science and Technology).Jimenez, N.; Romero García, V.; Groby, J. (2018). Perfect Absorption of Sound by Rigidly-Backed High-Porous Materials. Acta Acustica united with Acustica. 104(3):396-409. https://doi.org/10.3813/AAA.919183S396409104

Metamateriaux pour l'acoustique audible : Absorption parfaite et diffusion sublongueur d'onde

[FR] Dans ce travail, nous montrons les possibilités des métamatériaux acoustiques pour la conception de matériaux structurés sublongueur d'onde dans les cas de l¿absorption parfaite et la diffusion du son. Basé sur les concepts des ondes lentes et du couplage critique, nous concevons des blocs résonants qui peuvent être assemblés et ainsi réaliser des traitements pour l'absorption et la diffusion avec des performances équivalentes ou supérieures aux traitements acoustiques habituels. L'absorption parfaite est abordée à la fois dans les problèmes de réflexion pure et de transmission, deux problèmes de complexité croissante. Les diffuseurs ainsi que les absorbeurs parfaits sublongueur d'onde sont comparés aux traitements traditionnels, ce qui montre une nouvelle façon de concevoir des traitements acoustiques avec des propriétés accordables.[EN] In this work, we show the possibilities of acoustic metamaterials for designing subwavelength structured materials for perfect sound absorption and diffusion. Based on the concepts of slow waves and critical coupling, we design resonant building blocks that can be assembled to create deep subwavelength acoustic treatments for sound absorption and diffusion with performances equivalent or superior to the usual acoustic treatments. Perfect absorption is addressed in both pure reflection and transmission, two problems of increasing complexity. Diffusers as well as perfect absorbers, both with subwavelength dimensions, are compared to traditional treatments, showing a new way of designing acoustic treatments with tunable properties.Romero-García, V.; Pagneux, V.; Groby, J.; Jimenez, N.; Ballestero, E. (2020). Metamateriaux pour l'acoustique audible : Absorption parfaite et diffusion sublongueur d'onde. Acoustic & Techniques. 94/95:33-39. http://hdl.handle.net/10251/164477S333994/9

故富田博士記念事業資金募集廣告

While listeners' emotional response to music is the subject of numerous studies, less attention is paid to the dynamic emotion variations due to the interaction between artists and audiences in live improvised music performances. By opening a direct communication channel from audience members to performers, the Mood Conductor system provides an experimental framework to study this phenomenon. Mood Conductor facilitates interactive performances and thus also has an inherent entertainment value. The framework allows audience members to send emotional directions using their mobile devices in order to ``conduct'' improvised performances. Emotion coordinates indicted by the audience in the arousal-valence space are aggregated and clustered to create a video projection. This is used by the musicians as guidance, and provides visual feedback to the audience. Three different systems were developed and tested within our framework so far. These systems were trialled in several public performances with different ensembles. Qualitative and quantitative evaluations demonstrated that musicians and audiences were highly engaged with the system, and raised new insights enabling future improvements of the framework