Rotational viscoelastic laminar boundary layer flow around a rotating disc

The equations of motion for the laminar boundary layer flow over a rotating disc have been derived for a fluid which obeys a Rivlin-Ericksen type of constitutive equation and whose material parameters are assumed to be arbitrary functions of the second invariant of the rate of deformation tensor. The analysis establishes the conditions under which a true similarity solution is possible. An inspectional analysis yields a relationship between the moment coefficient, a generalized Reynolds number and a modified Weissenberg number which incorporates a variable relaxation time with a process time characteristic of the boundary layer flow on the disc. Experimental data obtained are analysed in terms of the derived relationship and the agreement between the two, after the determination of the unknown constants, is found to be quite sound. A brief discussion follows which emphasizes the role of geometry, regime of flow and viscoelastic material parameters in giving a wide variety of flow phenomena

On the absence of radio halos in clusters with double relics

Pairs of radio relics are believed to form during cluster mergers, and are best observed when the merger occurs in the plane of the sky. Mergers can also produce radio halos, through complex processes likely linked to turbulent re-acceleration of cosmic-ray electrons. However, only some clusters with double relics also show a radio halo. Here, we present a novel method to derive upper limits on the radio halo emission, and analyse archival X-ray Chandra data, as well as galaxy velocity dispersions and lensing data, in order to understand the key parameter that switches on radio halo emission. We place upper limits on the halo power below the $P_{\rm 1.4 \, GHz}\, M_{500}$ correlation for some clusters, confirming that clusters with double relics have different radio properties. Computing X-ray morphological indicators, we find that clusters with double relics are associated with the most disturbed clusters. We also investigate the role of different mass-ratios and time-since-merger. Data do not indicate that the merger mass ratio has an impact on the presence or absence of radio halos (the null hypothesis that the clusters belong to the same group cannot be rejected). However, the data suggests that the absence of radio halos could be associated with early and late mergers, but the sample is too small to perform a statistical test. Our study is limited by the small number of clusters with double relics. Future surveys with LOFAR, ASKAP, MeerKat and SKA will provide larger samples to better address this issue.Comment: 12 pages, 7 figures, MNRAS accepte

Snail Homing and Mating Search Algorithm: A Novel Bio-Inspired Metaheuristic Algorithm

In this paper, a novel Snail Homing and Mating Search (SHMS) algorithm is proposed. It is inspired from the biological behaviour of the snails. Snails continuously travels to find food and a mate, leaving behind a trail of mucus that serves as a guide for their return. Snails tend to navigate by following the available trails on the ground and responding to cues from nearby shelter homes. The proposed SHMS algorithm is investigated by solving several unimodal and multimodal functions. The solutions are validated using standard statistical tests such as two-sided and pairwise signed rank Wilcoxon test and Friedman rank test. The solution obtained from the SHMS algorithm exhibited superior robustness as well as search space exploration capabilities within the less computational cost. The real-world application of SHMS algorithm is successfully demonstrated in the engineering design domain by solving three cases of design and economic optimization shell and tube heat exchanger problem. The objective function value and other statistical results obtained using SHMS algorithm are compared with other well-known metaheuristic algorithms.Comment: 46 Pages, 11 Figures, 24 Table

ELVIS - ELectromagnetic Vector Information Sensor

The ELVIS instrument was recently proposed by the authors for the Indian Chandrayaan-1 mission to the Moon and is presently under consideration by the Indian Space Research Organisation (ISRO). The scientific objective of ELVIS is to explore the electromagnetic environment of the moon. ELVIS samples the full three-dimensional (3D) electric field vector, E(x,t), up to 18 MHz, with selective Nyqvist frequency bandwidths down to 5 kHz, and one component of the magnetic field vector, B(x,t), from a few Hz up to 100 kHz.As a transient detector, ELVIS is capable of detecting pulses with a minimum pulse width of 5 ns. The instrument comprises three orthogonal electric dipole antennas, one magnetic search coil antenna and a four-channel digital sampling system, utilising flexible digital down conversion and filtering together with state-of-the-art onboard digital signal processing.Comment: 8 pages, 3 figures. Submitted to the DGLR Int. Symposium "To Moon and Beyond", Bremen, Germany, 2005. Companion paper to arXiv:astro-ph/050921

High Temperature Ferromagnetism with Giant Magnetic Moment in Transparent Co-doped SnO2-d

Occurrence of room temperature ferromagnetism is demonstrated in pulsed laser deposited thin films of Sn1-xCoxO2-d (x<0.3). Interestingly, films of Sn0.95Co0.05O2-d grown on R-plane sapphire not only exhibit ferromagnetism with a Curie temperature close to 650 K, but also a giant magnetic moment of about 7 Bohr-Magneton/Co, not yet reported in any diluted magnetic semiconductor system. The films are semiconducting and optically highly transparent.Comment: 12 pages, 4 figure

Alternative parallel ring protocols

Communication protocols are know to influence the utilization and performance of communication network. The effect of two token ring protocols on a gigabit network with multiple ring structure is investigated. In the first protocol, a mode sends at most one message on receiving a token. In the second protocol, a mode sends all the waiting messages when a token is received. The behavior of these protocols is shown to be highly dependent on the number of rings as well as the load in the network

Energy deposition in the ionosphere through a global field line resonance

International audienceWe present an interval whereby we can estimate the energy dissipation in the ionosphere through an externally-driven field line resonance. In this paper, we utilise an interval described in general by Rae et al. (2005), where the global magnetospheric cavity was shown to be energised via a high solar wind speed stream. Using the ground-based instrumentation available, we estimate the spatial extent of the generated pulsations to be at least 10° in latitude and 65° in longitude, a sizeable fraction of the dusk-sector ionosphere. Using a fortuitous conjunction with the Polar spacecraft, we compare point measurements of the net downward Poynting vector to the estimated Joule heating rate in the ionosphere, and find that model values of the Pedersen conductance are reasonable. In the interval of interest, we estimate the total dissipation rate during a global field line resonance to be comparable to that reported in substorm studies. Previous studies have estimated the total energy deposition via field line resonance to be up to 4% of that deposited during a small substorm. However, in this paper we find that the total energy deposited via Joule heating may actually be 30% or more of the energy deposited in the ionosphere during a substorm cycle using a conservative estimate of the pulsation duration

The Sensory Properties, Color, Microbial, Lipid Oxidation, and Residual Nitrite of Se’i Marinated with Lime and Roselle Calyces Extracts

Meat deterioration can occur because of lipid oxidation and bacteria that could affect meat quality. It has been recognized that fruits of lime (Citrus aurantifolia) and roselle (Hibiscus sabdariffa) calyces contain bioactive compounds that have a capability to prevent oxidation and bacterial growth. The objective of this research was to  investigate the effect of lime and roselle calyces extracts on se’i (Rotenese smoked beef) quality. Completely randomized design (CRD) with 2x4 factorial pattern was used in this study. The first factor (E) was source of extracts i.e., lime extract (E1) and roselle extract (E2). The second factor (L) was level of the extract consisted of 4 levels i.e., control (without extract/ L0); L1= 1%; L2= 2%; and L3= 3% (v/v). Each treatment consisted of 3 replications. Sensory properties measured were aroma, taste, and tenderness. Other variables measured were color, total plate count (TPC), thiobarbituric acid reactive substances (TBARS), and residual nitrite.  The taste and tenderness of se’i were affected (P&lt;0.05) by combination of the extract and the level of the extract.  Results showed that there were significant interactions (P&lt;0.05) between the kind of extracts and the level of extract on L (lightness), a (redness), and b (yellowness) values, TPC, TBARS, and residual nitrite values. The level of 3% of  lime extract as well as 3% of roselle calyces extract improved score of taste and tenderness, reduced a values, decreased TPC, TBARS, and residual nitrite values. Marinating in 3% of roselle calyces extract decreased the b value but marinating in 3% of lime increased the b value of se’i. It is concluded that marinating 3% of roselle or 3% of lime gives the best effect on taste, tenderness, TPC, and TBARS values of se’i

Kajian Upaya Peningkatan Mutu Sosis Tradisional Timor (Budik)

Penelitian ini bertujuan untuk meningkatkan mutu sosis tradisional Timor (budik) berbahan dasar daging babi. Daging babi merupakan hasil ternak yang dikonsumsi masyarakat. Selain mengandung unsur-unsur gizi seperti karbohidrat, protein, vitamin, dan mineral, daging babi memiliki kelebihan yakni mengandung banyak thiamin (vitamin B1) yang diperlukan oleh tubuh untuk mencerna karbohidrat dan menunjang kerja sistem saraf. Penelitian ini menggunakan daging babi dengan lima (5) perlakuan, yakni: P0: Darah 70% + Lemak bagian abdominal 30% sebagai kontrol P1: Darah 70% + Daging 30 %, P2: Darah 40% + Lemak bagian abdominal 20 % + Daging 40%, P3: Darah 35 % + Lemak bagian abdominal 20% + Daging 45 %, P4: Darah 30% + Lemak bagian Abdominal 20 % + Daging 50%. Parameter yang diuji dalam penelitian ini: kadar air, kadar abu, kadar protein, kadar lemak, serta warna, aroma, cita rasa dan tekstur. Rancangan yang digunakan adalah Rancangan Acak Lengkap (RAL). Data dianalisis dengan analysis of variance (ANOVA). Dilanjutkan dengan uji Duncan’s. Data non parametrik hasil uji hedonik dianalisis dengan uji Kruskal-Wallis. Simpulan penelitian ini adalah Perbedaan konsentrasi campuran daging dalam masing-masing perlakuan sosis tradisional Timor (budik) memberikan perbedaan yang nyata terhadap kadar air, kadar abu, kadar lemak dan kadar protein, serta warna, aroma, cita rasa dan tekstur. Berdasarkan dari hasil yang diperoleh masing-masing perlakuan terbaik dari penambahan daging babi adalah perlakuan P1 dengan menggunakan darah 70% dan daging 30

Rapid cell separation with minimal manipulation for autologous cell therapies

The ability to isolate specific, viable cell populations from mixed ensembles with minimal manipulation and within intra-operative time would provide significant advantages for autologous, cell-based therapies in regenerative medicine. Current cell-enrichment technologies are either slow, lack specificity and/or require labelling. Thus a rapid, label-free separation technology that does not affect cell functionality, viability or phenotype is highly desirable. Here, we demonstrate separation of viable from non-viable human stromal cells using remote dielectrophoresis, in which an electric field is coupled into a microfluidic channel using shear-horizontal surface acoustic waves, producing an array of virtual electrodes within the channel. This allows high-throughput dielectrophoretic cell separation in high conductivity, physiological-like fluids, overcoming the limitations of conventional dielectrophoresis. We demonstrate viable/non-viable separation efficacy of > 98% in pre-purified mesenchymal stromal cells, extracted from human dental pulp, with no adverse effects on cell viability, or on their subsequent osteogenic capabilities