Effects of Nanodots Shape and Lattice Constants on the Spin Wave Dynamics of Patterned Permalloy Dots

Micromagnetic simulations studies on Permalloy (Ni80Fe20) nanodot with different shape and edge-to-edge separation (s) down to 25nm arranged in square lattice are reported. We observe the significant variation of spin-wave (SW) dynamics of nanodots of different shapes (triangular, diamond and hexagon) and of fixed dot diameter 100nm with varying s. Modes for single dot are transformed in an array into multiple quantized, edge and centre modes for different shapes and edge-to-edge separations, with different spin wave frequencies and peak intensities. Specifically, in the triangular dot sample, a broad range of mode frequencies is observed with highest SW frequency 14.7 GHz. For separation less than 100nm, the SW frequencies undergoes significant modification due to the varying nature of the magnetostatic and dipolar interaction in the array while for separation above 100nm, the SW frequency mostly remain constant. The power profiles confirm the nature of the observed modes. The spatial profiles of magnetostatic field are determined by a combination of internal magnetic-field profiles within the nanodots and the magnetostatic fields within the lattice. The inter-dots interaction of magnetostatic field shows dipolar and quadrupole contributions for all the shapes. Interestingly, vortex states with shifted core and polarity are observed in the array for all the shapes at Hbias = 0. Our results provide important understanding about the tunability of SW spectra in the array of triangular, diamond and hexagon shaped nanoelements.Comment: 13 pages, 8 figure

Biodegradative Threonine Dehydratase. Reduction of Ferricyanide by an Intermediate of the Enzyme-Catalyzed Reaction

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65912/1/j.1432-1033.1978.tb12706.x.pd

Relativistic tidal properties of superfluid neutron stars

We investigate the tidal deformability of a superfluid neutron star. We calculate the equilibrium structure in the general relativistic two-fluid formalism with entrainment effect where we take neutron superfluid as one fluid and the other fluid is comprised of protons and electrons, making it a charge neutral fluid. We use a relativistic mean field model for the equation of state of matter where the interaction between baryons is mediated by the exchange $\sigma$, $\omega$ and $\rho$ mesons. Then, we study the linear, static $l=2$ perturbation on the star to compute the electric-type Love number following Hinderer's prescription.Comment: Accepted for publication in Physical Review

Effect of superfluid matter of neutron star on the tidal deformability

We study the effect of superfluidity on the tidal response of a neutron star in a general relativistic framework. In this work, we take a dual-layer approach where the superfluid matter is confined in the core of the star. Then, the superfluid core is encapsulated with an envelope of ordinary matter fluid which acts effectively as the low-density crustal region of the star. In the core, the matter content is described by a two-fluid model where only the neutrons are taken as superfluid and the other fluid consists of protons and electrons making it charge neutral. We calculate the values of various tidal love numbers of a neutron star and discuss how they are affected due to the presence of entrainment between the two fluids in the core. We also emphasize that more than one tidal parameter is necessary to probe superfluidity with the gravitational wave from the binary inspiral

Homoserine Dehydrogenase of Rhodospirillum rubrum

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65514/1/j.1432-1033.1978.tb12039.x.pd

Effect of Refrigerant Charge, Compressor Speed and Air Flow Through the Evaporator on the Performance of an Automotive Air Conditioning System

During last few decades research on Automotive Air Conditioning System (AACS) reached a milestone in terms of comfort, safety and economy. However investigation on system performance due to AACS’s variable operating conditions is limited. The performance of any AACS mostly depends on compressor speed, blower speed, refrigerant charge level and ambient condition. However, the combined effect of these parameters on the performance of AACS could be non-intuitive. Reduction in compressor speed and blower speed reduces the cooling capacity. Again, higher blower speed induces large volume of fresh air inside the cabin, which requires more compression work to maintain the same comfort level. Further the best performance of the system is achieved at an optimum charge level which is not independent of the other operating conditions. Therefore, it is essential to assess the performance of AACS for a wide combination of operating variables so that the range of optimum operating zone can be identified. With this purpose, an off board test bench has been developed for evaluating the performance of an automotive air conditioning system. The facility consists of the mechanical hardware used in an automobile along with a large number of additional sensors and a standalone control system that mimics the operations in a car. The experiments were carried out with varying compressor and blower speed along with a variable refrigerant charge for a given ambient condition. Total sixty set of experiments were conducted at 200, 300, 400, 500 and 600 g of refrigerant charge level. In each charge level the speed of the compressor was fixed at 1000, 1300, 1600 and 1900 rpm by using a variable frequency drive. Again in each compressor speed, the blower speed of the evaporator was selected at three different set points. The cooling capacity, compression work and COP of the system are reported in this paper over this wide operating range. It is observed that with the increase in compressor speed, cooling capacity and compression work increases along with a decrease in the COP of the system. The results indicate that the AACS could operate over a wide range of charge levels, 15% below to 15% above the design value without any significant impact on its performance. Beyond this range, the performance of the system was found to be strongly dependent upon the charge level. The degree of superheat at the evaporator outlet and degree of subcooling at the condenser outlet were shown to be significantly dependent on the level of refrigerant charge. Though the system performance depends on the speed of both the compressor and the blower, the effect of the latter on the refrigeration cycle is only marginal. The optimum operating condition with compressor and blower speed along with refrigerant charge level has also been identified

Impact of a 12-volt Lead Acid Battery State-of-Charge on the Performance of an Automotive Air Conditioning System

In most of the Automotive Air Conditioning Systems (AACSs) though the compressor is powered by the car engine, the evaporator blower and the condenser fan are run by an alternator. Further, this alternator is powered from engine shaft. If there is any fault in the alternator that must drop the output voltage. This variation in output voltage can be achieved from a car battery by regulating its charging current. Owing to this, a stationary test rig for an AACS is developed with all actual automotive components coupled with a large number of sensors and additional accessories. However, the present investigation is restricted only to its air conditioning system, the alternator is replaced by a 12 volt lead acid car battery (capacity: 36 Ah) to invigorate the maneuvering of compressor clutch engagement and disengagement as well, empowerment of the prime movers. Now, a continuous monitoring of the system performance is done at different battery charge level. A DC power source is used to keep the battery voltage constant in different levels by varying the charging current. Further, in each battery charge level tests are conducted at three different blower speeds by regulating the existing toggle switch of the automobile. It is observed that the evaporator blower and the condenser fan speeds reduces continuously with the discharging of the storage battery, resulting a certain drop in air flow rate across the heat exchangers. Hence, the discharge pressure and the temperature increases due to lack of proper cooling across the condenser. Here, the continuous monitoring of the battery discharge voltage and its impact on the deterioration on the system cooling capacity, compression work and the COP are reported

Preparation of serum capped silver nanoparticles for selective killing of microbial cells sparing host cells

Following access into the cell, colloidal silver nanoparticles exhibit generalized cytotoxic properties, thus appear as omnipotent microbicidal, but not suitable for systemic use unless are free of toxic effects on host cells. The AgNP-Serum-18 when prepared from silver nitrate, using dextrose as reducing and group-matched homologous serum as a stabilizing agent, selective endocytosis, and oxidative stress-dependent bio-functional damages to the host are mostly eliminated. For their bio-mimicking outer coat, there is the least possibility of internalization into host cells or liberation of excess oxidants in circulation following interaction with erythrocytes or vascular endothelial cells. The presence of infection-specific antibodies in the serum can make such nano-conjugates more selective. A potent antimicrobial action and a wide margin of safety for mammalian cells in comparison with very similar PVA-capped silver nanoparticles have been demonstrated by the in-vitro challenge of such nanoparticles on different microbes, human liver cell-line, and in-vivo study on mice model. This may open up wide-range therapeutic prospects of colloidal nanoparticles