Elementary example of energy and momentum of an extended physical system in special relativity

An instructive paradox concerning classical description of energy and momentum of extended physical systems in special relativity theory is explained using an elementary example of two point-like massive bodies rotating on a circle in their center-of-mass frame of reference, connected by an arbitrarily light and infinitesimally thin string. Namely, from the point of view of the inertial observers who move with respect to the rotating system, the sums of energies and momenta of the two bodies oscillate, instead of being constant in time. This result is understood in terms of the mechanism that binds the bodies: the string contributes to the system total energy and momentum no matter how light it is. Its contribution eliminates the unphysical oscillations from the system total four-momentum. Generality of the relativistic approach, applied here to the rotor example, suggests that in every extended physical system its binding mechanism contributes to its total energy and momentum.Comment: 33 pages, 6 figures, to be published in American Journal of Physics http://aapt.scitation.org/journal/ajp , added one referenc

Renormalized quark-antiquark Hamiltonian induced by a gluon mass ansatz in heavy-flavor QCD

In response to the growing need for theoretical tools that can be used in QCD to describe and understand the dynamics of gluons in hadrons in the Minkowski space-time, the renormalization group procedure for effective particles (RGPEP) is shown in the simplest available context of heavy quarkonia to exhibit a welcome degree of universality in the first approximation it yields once one assumes that beyond perturbation theory gluons obtain effective mass. Namely, in the second-order terms, the Coulomb potential with Breit-Fermi spin couplings in the effective quark-antiquark component of a heavy quarkonium, is corrected in one-flavor QCD by a spin-independent harmonic oscillator term that does not depend on the assumed effective gluon mass or the choice of the RGPEP generator. The new generator we use here is much simpler than the ones used before and has the advantage of being suitable for studies of the effective gluon dynamics at higher orders than the second and beyond the perturbative expansion.Comment: 8 pages, 2 figures, journal versio

Penyerapan Kadmium Pada Ayam Kampung Yang Diberi Dedak Padi Dalam Ransum

Phytate is commonly found in high concentration in rice bran. This compound can bind multivalency ions. The purpose of this study was to know the effect of rice bran in native chicken diet on Cd absorption. Twenty four native male chicks aged 3 months were randomly divided into six groups of treatments. The average weight of chick used in this experiment was 422.08 ± 39 g. The dietary treatments were 0% (R0), 10% (R1), 20% (R2), 30% (R3), 40% (R4), and 50% (R5) of rice bran in the ration given for 8 weeks. Drinking water containing 100 ppm Cd was given ad libitum. The results indicated that those treatments had no significant effect on Cd absorption, Cd concentration in feces, kidney, liver and weight of kidney and liver. Average of Cd in kidney and liver were 284.24 and 117.53 ppm respectively. It was concluded that rice bran in the native chick diet did not reduce Cd absorption. The utilization of rice bran and Cd pollution for long term period and in high concentration in the diet gave negative effect on native chicken performance

Efek Residu Dari Kombinasi Media Tanam Abu Vulkanik Merapi, Pupuk Kandang Sapi Dan Tanah Mineral Terhadap C-organik, Kapasitas Pegang Air, Kadar Air Dan Bobot Kering Pupus Tanaman Jagung (Zea Mays L.)

Setelah satu musim tanam, efek residu dari kombinasimedia tanam abu vulkanik Merapi (AVM), pupukkandang sapi (PKS) dan tanah mineral Inceptisol(TM) terhadap C-organik, kapasitas pegang air,kadar air, dan bobot kering pupus tanaman jagung(Zea mays L.) diamati lebih lanjut. Pengamatandilaksanakan dari bulan Februari-Mei 2012 di dalamrumah kaca kebun percobaan Fakultas Pertanian,Universitas Padjadjaran pada ketinggian tempat ±740 m dpl. Rancangan acak kelompok faktor tunggaldalam penelitian sebelumnya dengan sembilankombinasi perlakuan dan tiga kali ulangan tetapdilanjutkan. Hasil pengamatan menunjukkan bahwaresidu kombinasi AVM, PKS, dan TM memberikanpengaruh yang nyata terhadap C-organik, kapasitaspegang air dan kadar air. Kapasitas pegang air(86,93%) dan kadar air (8,33%) tertinggi diperolehdari residu kombinasi media tanam: 0% AVM+ 50% PKS + 50% TM, sedangkan kandunganC-organik tertinggi (6,32%) diperoleh dari residukombinasi: 10% AVM + 50% PKS + 40% TM.Seluruh residu kombinasi media tanam tidakberpengaruh terhadap bobot kering pupus tanamanjagung. Korelasi C-organik dengan kapasitas pegangair menunjukkan bahwa 57,2% kapasitas pegangair sangat dipengaruhi oleh C-organik; sedangkankadar air dalam media tanam (17,0%) dipengaruhioleh adanya C-organik

Spontaneous emission of color centers at 4eV in hexagonal boron nitride under hydrostatic pressure

The light emission properties of color centers emitting in 3.3-4 eV region are investigated for hydrostatic pressures ranging up to 5GPa at liquid helium temperature. The light emission energy decreases with pressure less sensitively than the bandgap. This behavior at variance from the shift of the bandgap is typical of deep traps. Interestingly, hydrostatic pressure reveals the existence of levels that vary differently under pressure (smaller increase of the emission wavelength compared to the rest of the levels in this energy region or even decrease of it) with pressure. This discovery enriches the physics of the color centers operating in the UV in hBN.Comment: 16 pages, 3 figure

Fisher profiles and perceptions of sea turtle-fishery interactions: case study of East Coast Peninsular Malaysia

The paper focuses on coastal fisheries, particularly examining sea turtle-fishery interactions and determining the socioeconomic profile and perception of local fishers about sea turtle issues along the East Coast of Peninsular Malaysia.Turtle fisheries, Nature conservation, Coastal fisheries, Man-induced effects, ISEW, Malaysia, Malaya, Pahang, Malaysia, Malaya, Kelantan, Malaysia, Malaya, Terengganu,

Chiral metamaterials with negative refractive index based on four "U" split ring resonators

A uniaxial chiral metamaterial is constructed by double-layered four "U" split ring resonators mutually twisted by 90 degrees. It shows a giant optical activity and circular dichroism. The retrieval results reveal that a negative refractive index is realized for circularly polarized waves due to the large chirality. The experimental results are in good agreement with the numerical results.Comment: 4 pages, 4 figures, Published as cover on AP

Pengaruh Metode Bermain terhadap Kemampuan Passing

Masalah dalam penelitian ini adalah rendahnya kemampuan Passingpemain SSB Bina Remaja Lumindai Kota Sawahlunto. Tujuan penelitian ini untuk membuktikan pengaruh metode bermain terhadap peningkatan kemampuan passing pemain SSB Bina Remaja Lumindai Kota Sawahlunto. Penelitian ini bersifat eksperimen semu yaitu memberikan perlakuan terhadap pemain SSB Bina Remaja Lumindai Kota Sawahlunto.Penelitian ini dilakukan dari bulan Mei sampai bulan Juli tahun 2018 di lapangan sepakbola SSB Bina Remaja Lumindai Kota Sawahlunto. Populasi dalam penelitian ini adalah Seluruh anggotanya terdiri dari kelompok pemula sampai kelompok senior terdiri atas 40 orang. Teknik pengambilan sampel adalah  purposive sampling, sampel yaitu sebanyak 20 orang. Data dianalisis dengan menggunakan teknik inferensial dengan formula uji  ‘t' sampel terikat. Hasil yang diperoleh dalam penelitian adalah sebagai berikut : didapat hasil dari pengujian tersebut dengan skor thit 11,95 untuk ttab pada taraf signifikan α = 0,05 yaitu 1,729, karena t­hit>ttab atau 11,95 > 1,729 maka terdapat pengaruh yang berarti metode bermain terhadap peningkatan kemampuan passingpemain SSB Bina Remaja Lumindai Kota Sawahlunto

Embedding colloidal nanoparticles inside mesoporous silica using gas expanded liquids for high loading recyclable catalysts

The ability to tune the structural and chemical properties of colloidal nanoparticles (NPs), make them highly advantageous for studying activity and selectivity dependent catalytic behaviour. Incorporating pre-synthesized colloidal NPs into porous supports materials remains a challenge due to poor wetting and pore permeability. In this report monodisperse, composition controlled AgPd alloy NPs were synthesised and embedded into SBA-15 using supercritical carbon dioxide and hexane. Supercritical fluid impregnation resulted in high metal loading without the requirement for surface pre-treatments. The catalytic activity, reaction profiles and recyclability of the alloy NPs embedded in SBA-15 and immobilised on non-porous SiO2 are evaluated. The NPs incorporated within the SBA-15 porous network showed significantly greater recyclability performance compared to non-porous SiO2

A Coupled Map Lattice Model for Rheological Chaos in Sheared Nematic Liquid Crystals

A variety of complex fluids under shear exhibit complex spatio-temporal behaviour, including what is now termed rheological chaos, at moderate values of the shear rate. Such chaos associated with rheological response occurs in regimes where the Reynolds number is very small. It must thus arise as a consequence of the coupling of the flow to internal structural variables describing the local state of the fluid. We propose a coupled map lattice (CML) model for such complex spatio-temporal behaviour in a passively sheared nematic liquid crystal, using local maps constructed so as to accurately describe the spatially homogeneous case. Such local maps are coupled diffusively to nearest and next nearest neighbours to mimic the effects of spatial gradients in the underlying equations of motion. We investigate the dynamical steady states obtained as parameters in the map and the strength of the spatial coupling are varied, studying local temporal properties at a single site as well as spatio-temporal features of the extended system. Our methods reproduce the full range of spatio-temporal behaviour seen in earlier one-dimensional studies based on partial differential equations. We report results for both the one and two-dimensional cases, showing that spatial coupling favours uniform or periodically time-varying states, as intuitively expected. We demonstrate and characterize regimes of spatio-temporal intermittency out of which chaos develops. Our work suggests that such simplified lattice representations of the spatio-temporal dynamics of complex fluids under shear may provide useful insights as well as fast and numerically tractable alternatives to continuum representations.Comment: 32 pages, single column, 20 figure