Red Mud Pollution Problems : Some observations

The problem of pollution caused by red mud disposal and alternatively its utilisation has remained unsolved eversince industrial production of alumina from bauxite started as a commercial venture in 1860. Indigenous efforts to utilise this collosal waste have been limited since R&D efforts in this direction lacked coordination and adequate funding. In this paper the scientific and technological approaches to tackle this problem have been discussed and few conventional as well as novel approaches are presented. While looking for economics of alumina production, ecology has totally been ignored and time has come to realign our thinking and planning process to find a tangible solution

Semi-Empirical Bound on the Chlorinr-37 Solar Neutrino Experiment

The Kamiokande measurement of energetic Boron-8 neutrinos from the sun is used to set a lower bound on the contribution of the same neutrinos to the signal in the \Chlorine\ experiment. Implications for Beryllium-7 neutrinos are discussed.Comment: Latex, 6 pages + 1 postscript figure (included). UTAPHY-HEP-

Public Perception on Historical Landscape of Ethnic Immigrant Heritage in Heritage City of Baubau

As a one of the heritage cities in Indonesia, Baubau has many historical heritages which are not only created by local ethnics but also by immigrants. There are three historical landscapes created by the immigrants like China Town by Chinese, Waliabuku by Bugisnese, and Ngkaring-Ngkaring by Balinese. Until now, proper management to preserve the landscapes does not exist and it remains unknown whether this phenomenon is caused by the public perception who think that historical landscapes of immigrants as an unimportant heritage. The objective of this study is to investigate the public perception of historical landscapes that are created by immigrant in Baubau city as an heritage city in Indonesia. The results of survey show that the public regard all historical landscapes must be preserved. However, the landscapes created by the ethnic of Chinese have the lowest degree of public selection as compared to the ethnics of Bali and Bugis. The situation is triggered by the stereotype on the ethnic of Chinese which state that they tend to be more closed and reserved. Sebagai salah satu kota pusaka di Indonesia, Baubau memiliki banyak peninggalan sejarah bukan hanya yang dibentuk oleh etnis lokal, tetapi juga oleh etnis pendatang. Setidaknya terdapat tiga lanskap sejarah yang dibentuk oleh etnis pendatang yaitu lanskap pecinan oleh etnis Tionghoa, lanskap Waliabuku oleh etnis Bugis, dan lanskap Ngkaring-Ngkaring oleh etnis Bali. Sampai saat ini belum ada pengelolaan untuk melestarikan ketiga lanskap tersebut dan belum diketahui apakah fenomena ini dipengaruhi oleh persepsi masyarakat yang merasa lanskap peninggalan etnis pendatang tidaklah penting? Tujuan penelitian ini yaitu mengkaji persepsi masyarakat terhadap lanskap sejarah peninggalan etnis pendatang sebagai aset pusaka Kota Baubau sebagai kota pusaka Indonesia. Hasil yang diperoleh dari survei yang dilakukan, masyarakat umumnya menganggap seluruh lanskap sejarah harus dilestarikan tidak memandang apakah dibentuk oleh etnis lokal atau pendatang. Meskipun demikian, lanskap yang dibentuk oleh etnis Tionghoa memiliki derajat pemilihan paling rendah dari lanskap yang dibentuk etnis Bali dan Bugis. Hal ini disebabkan oleh adanya stereotip akibat karakter etnis Tionghoa yang dianggap masyarakat cenderung tertutup di Kota Baubau

Staging superstructures in high-TcT_c Sr/O co-doped La2−x_{2-x}Srx_xCuO4+y_{4+y}

We present high energy X-ray diffraction studies on the structural phases of an optimal high-$T_c$ superconductor La$_{2-x}$Sr$_x$CuO$_{4+y}$ tailored by co-hole-doping. This is specifically done by varying the content of two very different chemical species, Sr and O, respectively, in order to study the influence of each. A superstructure known as staging is observed in all samples, with the staging number $n$ increasing for higher Sr dopings $x$. We find that the staging phases emerge abruptly with temperature, and can be described as a second order phase transition with transition temperatures slightly depending on the Sr doping. The Sr appears to correlate the interstitial oxygen in a way that stabilises the reproducibility of the staging phase both in terms of staging period and volume fraction in a specific sample. The structural details as investigated in this letter appear to have no direct bearing on the electronic phase separation previously observed in the same samples. This provides new evidence that the electronic phase separation is determined by the overall hole concentration rather than specific Sr/O content and concommittant structural details.Comment: 8 pages, incl. 4 figure

Bulk and edge excitations of a ν=1\nu =1 Hall ferromagnet

In this article, we shall focus on the collective dynamics of the fermions in a $\nu = 1$ quantum Hall droplet. Specifically, we propose to look at the quantum Hall ferromagnet. In this system, the electron spins are ordered in the ground state due to the exchange part of the Coulomb interaction and the Pauli exclusion principle. The low energy excitations are ferromagnetic magnons. In order to obtain an effective Lagrangian for these magnons, we shall introduce bosonic collective coordinates in the Hilbert space of many-fermion systems. These collective coordinates describe a part of the fermionic Hilbert space. Using this technique, we shall interpret the magnons as bosonic collective excitations in the Hilbert space of the many-electron Hall system. Furthermore, by considering a Hall droplet of finite extent, we shall also obtain the effective Lagrangian governing the spin collective excitations at the edge of the sample.Comment: 30 pages, plain TeX, no figure

Spatial distribution of persistent sites

We study the distribution of persistent sites (sites unvisited by particles $A$) in one dimensional $A+A\to\emptyset$ reaction-diffusion model. We define the {\it empty intervals} as the separations between adjacent persistent sites, and study their size distribution $n(k,t)$ as a function of interval length $k$ and time $t$. The decay of persistence is the process of irreversible coalescence of these empty intervals, which we study analytically under the Independent Interval Approximation (IIA). Physical considerations suggest that the asymptotic solution is given by the dynamic scaling form $n(k,t)=s^{-2}f(k/s)$ with the average interval size $s\sim t^{1/2}$. We show under the IIA that the scaling function $f(x)\sim x^{-\tau}$ as $x\to 0$ and decays exponentially at large $x$. The exponent $\tau$ is related to the persistence exponent $\theta$ through the scaling relation $\tau=2(1-\theta)$. We compare these predictions with the results of numerical simulations. We determine the two-point correlation function $C(r,t)$ under the IIA. We find that for $r\ll s$, $C(r,t)\sim r^{-\alpha}$ where $\alpha=2-\tau$, in agreement with our earlier numerical results.Comment: 15 pages in RevTeX, 5 postscript figure

Cascade of Complexity in Evolving Predator-Prey Dynamics

We simulate an individual-based model that represents both the phenotype and genome of digital organisms with predator-prey interactions. We show how open-ended growth of complexity arises from the invariance of genetic evolution operators with respect to changes in the complexity, and that the dynamics which emerges is controlled by a non-equilibrium critical point. The mechanism is analogous to the development of the cascade in fluid turbulence.Comment: 5 pages, 3 figures; added comments on system size scaling and turbulence analogy, added error estimates of data collapse parameters. Slightly enhanced from the version which will appear in PR

Stochastic Energetics of Quantum Transport

We examine the stochastic energetics of directed quantum transport due to rectification of non-equilibrium thermal fluctuations. We calculate the quantum efficiency of a ratchet device both in presence and absence of an external load to characterize two quantifiers of efficiency. It has been shown that the quantum current as well as efficiency in absence of load (Stokes efficiency) is higher as compared to classical current and efficiency, respectively, at low temperature. The conventional efficiency of the device in presence of load on the other hand is higher for a classical system in contrast to its classical counterpart. The maximum conventional efficiency being independent of the nature of the bath and the potential remains the same for classical and quantum systems.Comment: To be published in Phys. Rev.