New Upper Limit of Terrestrial Equivalence Principle Test for Rotating Extended Bodies

Improved terrestrial experiment to test the equivalence principle for rotating extended bodies is presented, and a new upper limit for the violation of the equivalence principle is obtained at the level of 1.6$10^{\text{-7}}$, which is limited by the friction of the rotating gyroscope. It means the spin-gravity interaction between the extended bodies has not been observed at this level.Comment: 4 page

Preface paper to the Semi-Arid Land-Surface-Atmosphere (SALSA) Program special issue

The Semi-Arid Land-Surface-Atmosphere Program (SALSA) is a multi-agency, multi-national research effort that seeks to evaluate the consequences of natural and human-induced environmental change in semi-arid regions. The ultimate goal of SALSA is to advance scientific understanding of the semi-arid portion of the hydrosphere–biosphere interface in order to provide reliable information for environmental decision making. SALSA approaches this goal through a program of long-term, integrated observations, process research, modeling, assessment, and information management that is sustained by cooperation among scientists and information users. In this preface to the SALSA special issue, general program background information and the critical nature of semi-arid regions is presented. A brief description of the Upper San Pedro River Basin, the initial location for focused SALSA research follows. Several overarching research objectives under which much of the interdisciplinary research contained in the special issue was undertaken are discussed. Principal methods, primary research sites and data collection used by numerous investigators during 1997–1999 are then presented. Scientists from about 20 US, five European (four French and one Dutch), and three Mexican agencies and institutions have collaborated closely to make the research leading to this special issue a reality. The SALSA Program has served as a model of interagency cooperation by breaking new ground in the approach to large scale interdisciplinary science with relatively limited resources

Scholarly publishing depends on peer reviewers

The peer-review crisis is posing a risk to the scholarly peer-reviewed journal system. Journals have to ask many potential peer reviewers to obtain a minimum acceptable number of peers accepting reviewing a manuscript. Several solutions have been suggested to overcome this shortage. From reimbursing for the job, to eliminating pre-publication reviews, one cannot predict which is more dangerous for the future of scholarly publishing. And, why not acknowledging their contribution to the final version of the article published? PubMed created two categories of contributors: authors [AU] and collaborators [IR]. Why not a third category for the peer-reviewer?Scopu

A service collaboration strategy for MANETs

10.1109/INDIN.2006.2757522006 IEEE International Conference on Industrial Informatics, INDIN'06155-15

Bonding mechanisms of carbon fiber-reinforced plastic/aluminum alloy interface during friction lap welding via silane coupling treatment

Silane coupling pretreatment could usually increase the strength of metal/plastic-based material joints, however, the detailed chemical bonding mechanism has not been clarified so far, which has become a key bottleneck for the further expanding application of this technology. Here, a specially designed silane coupling treatment was conducted on the aluminum alloy surface, and a strong friction lap welding (FLW) joint of carbon fiber-reinforced thermoplastic (CFRTP) to aluminum alloy was obtained. The average tensile shear force of 6.83 kN (∼30.36 MPa) was obtained, approximately 140% higher than the untreated joint, which was higher than the results obtained via FLW ever reported. The detailed bonding mechanism at the interface was studied by high-resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and Fourier transform infrared reflection. It was found that the coupling agent layer observed at the interface acted as a bridge to achieve a tight bond with aluminum alloy and CFRTP. The bonding between the coupling agent layer and the aluminum alloy was achieved via the Si–O–Al and Si–O–Mg bonds, and the covalent bonding of C(=O)–N was formed by the chemical reaction between the CO bonds of CFRTP and the amino groups (-NH2) of the coupling agent layer, resulting in the tight joining at the atomic scale. These chemical bonds contributed to the joint strength, which provided a better understanding of the joining mechanisms of plastic-based materials to metals via silane coupling treatment

Realizing deep penetration and superior mechanical properties in a titanium alloy thick plate joint via vacuum laser beam welding

It is usually very difficult for achieving deep penetration in titanium alloy thick plates by conventional laser beam welding (LBW) under the atmospheric environment, since the laser beam energy is easily dissipated in air. In this study, LBW in a low vacuum environment (100 Pa) was proposed to realize the deep weld penetration of 16 mm of Ti–6Al–4V alloy thick plate, which was over 1 time deeper than that in the atmospheric joint (7 mm). In addition, the contents of the impurity gas elements (N, H and O) hardly changed after vacuum LBW (VLBW), ensuring the welding quality. The fusion zone mainly consisted of acicular α′ martensite, which enhanced the α′/α′ interface strengthening, resulting in the higher microhardness than that of the base material. The average tensile strength of the joint achieved 1010 MPa, with the strength efficiency 100%. Microstructure evolution mechanisms during VLBW were discussed. This study provides a reference for the engineering application of VLBW of titanium alloy thick plates

Achieving a large-area bulk ultrafine-grained titanium alloy with high thermal stability via layer-by-layer multi-pass overlapping friction stir processing

It is difficult to prepare large-area bulk ultrafine-grained (UFGed) titanium alloys with uniform structure via multi-pass overlapping friction stir processing (MP-FSP) due to the low thermal conductivity and poor flow deformation ability of titanium alloys. Here, we proposed a new layer-by-layer MP-FSP method to control the defect and microstructure of the Ti–6Al–4V alloy. As a result, the as-cast coarse microstructure was changed directly to the defect-free large-area bulk UFG microstructure. The bulk UFG exhibited a uniform microstructure with average grain sizes of 0.7–0.82 μm and over 90% of high angle grain boundaries. Moreover, the bulk UFG titanium alloy exhibited high hardness (357 HV) and great ultimate tensile strength (1177 MPa), which were much higher than those (308 HV and 739 MPa) of the base material. In addition, the bulk UFG had good thermal stability at a high temperature of 700 °C. Different from the bulk MP-FSP UFGed aluminium alloys where there is generally abnormal grain growth (AGG) at high temperatures, there was no AGG phenomenon in bulk MP-FSP UFGed titanium alloys even at 900 °C. This study provides an effective short-process method for preparing large-area bulk UFG titanium alloys with uniform structure and good thermal stability

Determination of Raman phonon strain shift coefficient of strained silicon and strained SiGe

10.1143/JJAP.44.7922Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers44117922-7924JAPN

Effects of welding speed on the multiscale residual stresses in friction stir welded metal matrix composites

The effects of welding speed on the macroscopic and microscopic residual stresses (RSes) in friction stir welded 17 vol.% SiCp/2009Al-T4 composite plates were studied via neutron diffraction and an improved decoupled hierarchical multiscale modeling methods. Measurements showed that the macroscopic and total RSes had the largest variations in the longitudinal direction (LD). Increasing the welding speed led to higher values of measured LD macroscopic and total RSes in the matrix. The welding speed also significantly influenced the distributions and magnitudes of the microscopic RSes. The RSes were predicted via an improved hierarchical multiscale model, which includes a constant coefficient of friction based thermal model. The RSes in the composite plates before friction stir welding (FSW) were computed and then set as the initial states of the FSW process during modeling. This improved decoupled multiscale model provided improved predictions of the temperature and RSes compared with our previous model