We present a multiwavelength analysis of a sample of four hot (T X > 8 keV) X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined with published X-ray temperatures, to examine the distribution of mass and the intracluster medium (ICM) in massive cluster environments. Our observations show that A2261 is very similar to A1689 in terms of lensing properties. Many tangential arcs are visible around A2261, with an effective Einstein radius ∼ 40 ′′ (at z ∼ 1.5), which when combined with our weak lensing measurements implies a mass profile well fitted by an NFW model with a high concentration c vir ∼ 10, similar to A1689 and to other massive clusters. The cluster A2142 shows complex mass substructure, and displays a shallower profile (c vir ∼ 5), consistent with detailed X-ray observations which imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature associated with mass substructure lying ahead of the sharp north-west edge of the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain highly elliptical mass and ICM distributions at all radii, consistent with other X-ray and strong lensing work. Our cluster gas fraction measurements, free from the hydrostatic equilibrium assumption, are overall in good agreement with published X-ray and SZE observations, with the sample-averaged gas fraction of f gas (< r 200 ) = 0.133 ± 0.027, for our sample with M vir = (1.2 ± 0.1) × 10 15 M ⊙ h −1 . When compared to the cosmic baryon fraction f b = Ω b /Ω m constrained by the WMAP 5-year data, this indicates f gas,200 / f b = 0.78 ± 0.16, i.e., (22 ± 16)% of the baryons are missing from the hot phase of clusters.

A new ideal mechanical one-port network element named the inerter was recently introduced, and shown to be realisable, with the property that the applied force is proportional to the relative acceleration across the element. This paper makes a comparative study of several simple passive suspension struts, each containing at most one damper and inerter as a preliminary investigation into the potential performance advantages of the element. Improved performance for several different measures in a quarter-car model is demonstrated here in comparison with a conventional passive suspension strut. A study of a full-car model is also undertaken where performance improvements are also shown in comparison to conventional passive suspension struts. A prototype inerter has been built and tested. Experimental results are presented which demonstrate a characteristic phase advance property which cannot be achieved with conventional passive struts consisting of springs and dampers only.

A new ideal mechanical one-port network element named the inerter was recently introduced, and shown to be realisable, with the property that the applied force is proportional to the relative acceleration across the element. This paper makes a comparative study of several simple passive suspension struts, each containing at most one damper and inerter as a preliminary investigation into the potential performance advantages of the element. Improved performance for several different measures in a quarter-car model is demonstrated here in comparison with a conventional passive suspension strut. A study of a full-car model is also undertaken where performance improvements are also shown in comparison to conventional passive suspension struts. A prototype inerter has been built and tested. Experimental results are presented which demonstrate a characteristic phase advance property which cannot be achieved with conventional passive struts consisting of springs and dampers only.

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This article proposes a novel hydraulic inerter and experimentally verifies its properties. The inerter is a true two-terminal mechanical network element, which was invented to substitute for the mass in mechanical/electrical analogies. Previously, inerter concepts have been realized by rack-and-pinion and ball-screw devices. This article introduces a new hydraulic inerter device in which the forces are translated by hydraulic means. The dynamics of the device is discussed and experimentally verified. On the basis of the results, the proposed hydraulic inerter is shown to be effective.

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This article investigates the performance benefits of building suspension systems that employ a newly developed mechanical element called an inerter. The inerter was proposed as a genuine two-terminal mechanical device to substitute for the mass element, which allows mechanical and electrical networks to become truly analogous. This study applied inerters to building suspension control. First, a one-degree-of-freedom (DOF) building model was examined in order to show the significant performance improvement by inerters, especially with a multilayer design. Second, the discussion was extended to a two-DOF building model. Finally, a ballscrew inerter was constructed for testing. From the results, the inerters were deemed effective in reducing building vibrations. Downloaded from S1J× 10 3 , c = 5.86 × 10 5 b = 3.61 × 10 5 , c = 3.04 × 10 6 k c1 = 3.19 × 10 6 , k c2 = 7.58 × 10 5 k c1 = 3.28 × 10 6 , k c2 = 8.36 × 10 5 b in the unit of kg, c in the unit of Ns/m, and static stiffness k = 5 × 10 6 N/m. JMES1909Proc. IMechE Vol. 224 Part C: J. Mechanical Engineering Science Performance index LayoutTraffic factor Earthquake J ∞ S1 J ∞ = 1.4 × 10 −3 J ∞ = 0.1616 c b = 7.06 × 10 −4 , c s = 4.10 × 10 −3 c b = 1.16 × 10 −2 , c s = 6.98 × 10 −2 S2 J ∞ = 6.66 × 10 −4 (52% improvement) J ∞ = 0.0611 (62% improvement) b b = 2.57 × 10 3 , b s = 2.85 × 10 3 b b = 3.12 × 10 5 , b s = 9.42 × 10 4 c b = 3.3 × 10 −3 , c s = 7.39 × 10 −4 c b = 3.15 × 10 3 , c s = 5.31 × 10 5 S3 J ∞ = 5.28 × 10 −4 (62% improvement) J ∞ = 0.0534 (67% improvement) b b = 2.97 × 10 3 , b s = 4.47 × 10 3 b b = 3.16 × 10 5 , b s = 4.53 × 10 5 c b = 2.75 × 10 5 , c s = 1.49 × 10 6 c b = 2.7 × 10 6 , c s = 1.47 × 10 7 J 2 S110 × 10 3 b b = 2.49 × 10 4 , b s = 7.58 × 10 4 c b = 6.56 × 10 3 , c s = 1.08 × 10 4 c b = 7.95 × 10 4 , c s = 1.28 × 10 5 S3 J 2 = 3.10 × 10 −3 (31% improvement) J 2 = 0.1253 (20% improvement) b b = 938.4, b s = 2.24 × 10 3 b b = 1.27 × 10 5 , b s = 1.75 × 10 4 c b = 3.77 × 10 5 , c s = 8.69 × 10 5 c b = 1.20 × 10 6 , c s = 4.97 × 10 5 b in the unit of kg, c in the unit of Ns/m, and static stiffness k b = k s = 5 × 10 6 N/m.

No abstract