Stability Properties of the Time Domain Electric Field Integral Equation Using a Separable Approximation for the Convolution with the Retarded Potential

The state of art of time domain integral equation (TDIE) solvers has grown by leaps and bounds over the past decade. During this time, advances have been made in (i) the development of accelerators that can be retrofitted with these solvers and (ii) understanding the stability properties of the electric field integral equation. As is well known, time domain electric field integral equation solvers have been notoriously difficult to stabilize. Research into methods for understanding and prescribing remedies have been on the uptick. The most recent of these efforts are (i) Lubich quadrature and (ii) exact integration. In this paper, we re-examine the solution to this equation using (i) the undifferentiated form of the TD-EFIE and (ii) a separable approximation to the spatio-temporal convolution. The proposed scheme can be constructed such that the spatial integrand over the source and observer domains is smooth and integrable. As several numerical results will demonstrate, the proposed scheme yields stable results for long simulation times and a variety of targets, both of which have proven extremely challenging in the past.Comment: 9 pages, 13 figures. To be published in IEEE Transactions on Antennas and Propagatio

Condition and relative condition cycles in the tropical glassy perchlet Chanda (=Ambassis)commersonii(Cuv. and Val.) (Pisces: Centropomidae)

The seasonal condition (K) and relative condition (K n ) cycles and their changes with the growth of the fish Chanda commersonii (Cuv. and Val.) for 2 yrs are presented. Better K is shown by the smaller immature and first maturity stages and larger, almost senile groups but they show a K n factor below '1'. The actively breeding adults show a uniform fail inK but they give comparatively high K n values (above '1'). These changes in K and K n with the growth of the fish are clearly reflected in their seasonal cycles also.K cycle would thus appear to follow a pattern of build up and loss of body resources, indirectly following the breeding cycle while the K n cycle follow the breeding and feeding cycles directly, as shown by their seasonal changes and changes with growth of the fish for 2 yrs. Since only minor deviations from unity occur in K n factor it furnishes a more sensitive index of somatic difference between age groups, of breeding season and feeding cycle

Effect of salinity on the survival and growth ofChanda (=Ambassis) gymnocephalus (Lac.) fry (Pisces; Centropomidae)

The survival and growth of Chanda (= Ambassis) gymnocephalus (Lac.) fry (8.8 ± 0.2mm) collected from Murukumpuzha Lake (9.34%) for a ninety day period in different salinity grades were studied. A faster rate of growth is exhibited by the fish in the highest salinity grades (22.41 and 28.51%), even though during the first month, growth and health was apparently better in the lower salinity grades (4.11, 10.21 and 16.31%). Assimilation efficiency also showed a similar gross picture. Thus inC. gymnocephalus, an euryhaline species, the fry show preferred salinity gradients for optimum growth within the fluctuating salinity regime at a stable temperature (26 ± 2°C) and hence may make salinity bound emigrations with growth

2015-ലെ കേരളത്തിലെ മത്സ്യബന്ധനവും മത്സ്യസമ്പത്തും

2015-ലെ കേരളത്തിലെ മത്സ്യബന്ധനവും മത്സ്യസമ്പത്തു

The Latin Leaflet, Number 29

Polymer electrolytes represent the ultimate in terms of desirable properties of energy storage/conversion devices, as they can offer an all-solid-state construction, a wide variety of shapes and sizes, light-weight, low costs, high energy density and safety. Here we present our recent results concerning a novel strategy for preparing efficient polymer membranes which are successfully demonstrated as suitable electrolytes for several energy conversion and storage devices (i.e., Li- and Na-based batteries and DSSCs). Highly ionic conducting polymer electrolytes containing PEO-based functionalities and different components (e.g., Li/Na salts, RTILs, natural biosourced and cellulosic fillers) are successfully prepared via a rapid process and, directly or subsequently, cross-linked via UV irradiation (patent pending, PCT/IT2014/000008). All the prepared materials are thoroughly characterised in terms of their physical, chemical and morphological properties and tested for their electrochemical performances and durability. The UV-curing process on such materials led to the production of elastic and resistant amorphous macromolecular networks. Noticeably increased ionic conductivities are registered (10-3 S cm-1 at RT), along with very stable interfacial and storage stability and wide electrochemical stability windows. The different lab-scale solid-state devices show remarkable performances even at ambient temperature, at the level of those using liquid electrolytes, respect to which demonstrate much greater durability and safety. The obtained findings demonstrate a new, easy and low cost approach to fabricate and tailor-make polymer electrolytes with highly promising prospects for the next generation of advanced flexible energy production and storage devices

Trypsin activity as a function of variation in shrimp Penaeus indicus(Crustacea/Arthropoda)

The effect of varying ration size on trypsin activity was evaluated in postlarvae, juvenile and adult P. indicus maintained on a commercial pelleted feed. Total trypsin activity reported as 11m p-nitroanilide produced/minute/g tissue was lower (4.23-6.68 11m) in postlarvae in comparison to juvenile (7.24-8.92 11m) and adult (10.23-12.24 1lJII) animals. Highest activity was detccted at 12%,8-12% and 4-6% in postlarvae, Juveniles and adult P. indicus respectively which were the optimum ration sizes. while lowest activity was obtained in the starved animals. Specific activity however exhibIted no significant variation with regard to ration size and starvation (P > O.1J5)

Synthesis, characterisation and gas permeation studies on microporous silica and alumina-silica membranes for separation of propane and propylene

Microporous silica membranes are known to exhibit molecular sieving effects. However, separation of nearly equal sized molecules is difficult to carry out by size exclusion. Introducing sorption selectivity and keeping the kinetics favourable to facilitate a good contribution of permeation from sorption is a possible solution to enhance selectivity of adsorbing molecules. Results are presented in this paper on the synthesis of a microporous silica membrane with commendable permselectivity between helium and propylene. Modifications are performed on the membrane to improve its almost non-selective nature to propylene/propane mixtures to give practical separation values. Gas separation results on the modified membranes are presented. Surface selectivity on the newly added alumina surface layer is identified as the helping mechanism in realising this separation

Twisted supersymmetric 5D Yang-Mills theory and contact geometry

We extend the localization calculation of the 3D Chern-Simons partition function over Seifert manifolds to an analogous calculation in five dimensions. We construct a twisted version of N=1 supersymmetric Yang-Mills theory defined on a circle bundle over a four dimensional symplectic manifold. The notion of contact geometry plays a crucial role in the construction and we suggest a generalization of the instanton equations to five dimensional contact manifolds. Our main result is a calculation of the full perturbative partition function on a five sphere for the twisted supersymmetric Yang-Mills theory with different Chern-Simons couplings. The final answer is given in terms of a matrix model. Our construction admits generalizations to higher dimensional contact manifolds. This work is inspired by the work of Baulieu-Losev-Nekrasov from the mid 90's, and in a way it is covariantization of their ideas for a contact manifold.Comment: 28 pages; v2: minor mistake corrected; v3: matches published versio