Hydrodynamics of the Oscillating Wave Surge Converter in the open ocean

A potential flow model is derived for a large flap-type oscillating wave energy converter in the open ocean. Application of the Green's integral theorem in the fluid domain yields a hypersingular integral equation for the jump in potential across the flap. Solution is found via a series expansion in terms of the Chebyshev polynomials of the second kind and even order. Several relationships are then derived between the hydrodynamic parameters of the system. Comparison is made between the behaviour of the converter in the open ocean and in a channel. The degree of accuracy of wave tank experiments aiming at reproducing the performance of the device in the open ocean is quantified. Parametric analysis of the system is then undertaken. It is shown that increasing the flap width has the beneficial effect of broadening the bandwidth of the capture factor curve. This phenomenon can be exploited in random seas to achieve high levels of efficiency.Comment: Submitted to: EJMB/Fluids, 16/07/201

High pressure magnetic state of MnP probed by means of muon-spin rotation

We report a detailed $\mu$SR study of the pressure evolution of the magnetic order in the manganese based pnictide MnP, which has been recently found to undergo a superconducting transition under pressure once the magnetic ground state is suppressed. Using the muon as a volume sensitive local magnetic probe, we identify a ferromagnetic state as well as two incommensurate helical states (with propagation vectors ${\bf Q}$ aligned along the crystallographic $c-$ and $b-$directions, respectively) which transform into each other through first order phase transitions as a function of pressure and temperature. Our data appear to support that the magnetic state from which superconductivity develops at higher pressures is an incommensurate helical phase.Comment: 11 pages, 9 figure

Soft x-rays absorption and high-resolution powder x-ray diffraction study of superconducting CaxLa(1-x)Ba(1.75-x)La(0.25+x)Cu3Oy system

We have studied the electronic structure of unoccupied states measured by O K-edge and Cu L-edge x-ray absorption spectroscopy (XAS), combined with crystal structure studied by high resolution powder x-ray diffraction (HRPXRD), of charge-compensated layered superconducting CaxLa(1-x)Ba(1.75-x)La(0.25+x)Cu3Oy (0<x<0.4, 6.4<y<7.3) cuprate. A detailed analysis shows that, apart from hole doping, chemical pressure on the electronically active CuO2 plane due to the lattice mismatch with the spacer layers greatly influences the superconducting properties of this system. The results suggest chemical pressure to be the most plausible parameter to control the maximum critical temperatures (Tcmax) in different cuprate families at optimum hole density.Comment: 14 pages, 11 figures, accepted for publication in Journal of Physics and Chemistry of Solid

Tuning the magnetic and structural phase transitions of PrFeAsO via Fe/Ru spin dilution

Neutron diffraction and muon spin relaxation measurements are used to obtain a detailed phase diagram of Pr(Fe,Ru)AsO. The isoelectronic substitution of Ru for Fe acts effectively as spin dilution, suppressing both the structural and magnetic phase transitions. The temperature of the tetragonal-orthorhombic structural phase transition decreases gradually as a function of x. Slightly below the transition temperature coherent precessions of the muon spin are observed corresponding to static magnetism, possibly reflecting a significant magneto-elastic coupling in the FeAs layers. Short range order in both the Fe and Pr moments persists for higher levels of x. The static magnetic moments disappear at a concentration coincident with that expected for percolation of the J1-J2 square lattice model

Perancangan Game Vokal-konsonan dan Tebak Huruf Berbasis Grafis

Kreativitas merupakan kemampuan intelegensia dari anak yang berhubungan dengan pengembangan logika, pengambilan keputusan, pengenalan terhadap objek dan bagaimana ia memanipulasi objek tersebut. Salah satu cara melatih daya ingat anak-anak adalah dengan diberikannya permainan seperti mencocokkan bentuk dan warna, game-game seperti scrabble, dan lain-lain. Selain dengan cara di atas saat ini media elektronik seperti komputer telah dapat digunakan untuk melatih daya ingat melalui game edukatif seperti game memory, game menebak gambar, dan game menebak kata. Dengan adanya permainan seperti ini ditambah lagi suatu perangkat lunak yang mengajarkan cara menyanyi maka diharapkan seorang anak dapat belajar sambil bermain sambil meningkatkan daya ingat. Selain dengan media lagu, kreativitas anak dapat digali dengan memainkan beberapa game edukatif seperti game memory, game menebak gambar, dan game menebak kata. Dengan adanya permainan seperti ini ditambah lagi suatu perangkat lunak yang mengajarkan cara menyanyi maka diharapkan seorang anak dapat belajar sambil bermain dan meningkatkan daya kreativitasnya. Hasil dari tulisan ini adalah suatu aplikasi yang dapat menghasilkan suatu lagu untuk anak-anak serta beberapa permainan untuk melatih daya ingat sehingga dapat meningkatkan fungsi otak kiri yang berkaitan dengan daya ingat

Understanding the μ\muSR spectra of MnSi without magnetic polarons

Transverse-field muon-spin rotation ($\mu$SR) experiments were performed on a single crystal sample of the non-centrosymmetric system MnSi. The observed angular dependence of the muon precession frequencies matches perfectly the one of the Mn-dipolar fields acting on the muons stopping at a 4a position of the crystallographic structure. The data provide a precise determination of the magnetic dipolar tensor. In addition, we have calculated the shape of the field distribution expected below the magnetic transition temperature $T_C$ at the 4a muon-site when no external magnetic field is applied. We show that this field distribution is consistent with the one reported by zero-field $\mu$SR studies. Finally, we present ab initio calculations based on the density-functional theory which confirm the position of the muon stopping site inferred from transverse-field $\mu$SR. In view of the presented evidence we conclude that the $\mu$SR response of MnSi can be perfectly and fully understood without invoking a hypothetical magnetic polaron state.Comment: 10 pages, 12 figure

Comparing perceived clarity of information on overdiagnosis used for breast and prostate cancer screening in England: an experimental survey.

OBJECTIVES: 'Overdiagnosis', detection of disease that would never have caused symptoms or death, is a public health concern due to possible psychological and physical harm but little is known about how best to explain it. This study evaluated public perceptions of widely used information on the concept to identify scope for improving communication methods. DESIGN: Experimental survey carried out by a market research company via face-to-face computer-assisted interviews. SETTING: Interviews took place in participants' homes. PARTICIPANTS: 2111 members of the general public in England aged 18-70 years began the survey; 1616 were eligible for analysis. National representativeness was sought via demographic quota sampling. INTERVENTIONS: Participants were allocated at random to receive a brief description of overdiagnosis derived from written information used by either the NHS Breast Screening Programme or the prostate cancer screening equivalent. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was how clear the information was perceived to be (extremely/very clear vs less clear). Other measures included previous exposure to screening information, decision-making styles and demographic characteristics (eg, education). Binary logistic regression was used to assess predictors of perceived clarity. RESULTS: Overdiagnosis information from the BSP was more likely to be rated as more clear compared with the prostate screening equivalent (adjusted OR: 1.43, 95% CI 1.17 to 1.75; p=0.001). Participants were more likely to perceive the information as more clear if they had previously encountered similar information (OR: 1.77, 1.40 to 2.23; p<0.0005) or a screening leaflet (OR: 1.35, 1.04 to 1.74; p=0.024) or had a more 'rational' decision-making style (OR: 1.06, 1.02 to 1.11; p=0.009). CONCLUSIONS: Overdiagnosis information from breast screening may be a useful template for communicating the concept more generally (eg, via organised campaigns). However, this information may be less well-suited to individuals who are less inclined to consider risks and benefits during decision-making

Effect of external pressure on the magnetic properties of RRCoAsO (RR = La, Pr, Sm): a μ\muSR study

We report on a detailed investigation of the itinerant ferromagnets LaCoAsO, PrCoAsO and SmCoAsO performed by means of muon spin spectroscopy upon the application of external hydrostatic pressures $p$ up to $2.4$ GPa. These materials are shown to be magnetically hard in view of the weak dependence of both critical temperatures $T_{C}$ and internal fields at the muon site on $p$. In the cases $R$ = La and Sm, the behaviour of the internal field is substantially unaltered up to $p = 2.4$ GPa. A much richer phenomenology is detected in PrCoAsO instead, possibly associated with a strong $p$ dependence of the statistical population of the two different crystallographic sites for the muon. Surprisingly, results are notably different from what is observed in the case of the isostructural compounds $R$CoPO, where the full As/P substitution is already inducing a strong chemical pressure within the lattice but $p$ is still very effective in further affecting the magnetic properties.Comment: 8 pages, 9 figure