A search for technosignatures from 14 planetary systems in the Kepler field with the Green Bank Telescope at 1.15-1.73 GHz

Analysis of Kepler mission data suggests that the Milky Way includes billions of Earth-like planets in the habitable zone of their host star. Current technology enables the detection of technosignatures emitted from a large fraction of the Galaxy. We describe a search for technosignatures that is sensitive to Arecibo-class transmitters located within ~420 ly of Earth and transmitters that are 1000 times more effective than Arecibo within ~13 000 ly of Earth. Our observations focused on 14 planetary systems in the Kepler field and used the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. Each source was observed for a total integration time of 5 minutes. We obtained power spectra at a frequency resolution of 3 Hz and examined narrowband signals with Doppler drift rates between +/-9 Hz/s. We flagged any detection with a signal-to-noise ratio in excess of 10 as a candidate signal and identified approximately 850 000 candidates. Most (99%) of these candidate signals were automatically classified as human-generated radio-frequency interference (RFI). A large fraction (>99%) of the remaining candidate signals were also flagged as anthropogenic RFI because they have frequencies that overlap those used by global navigation satellite systems, satellite downlinks, or other interferers detected in heavily polluted regions of the spectrum. All 19 remaining candidate signals were scrutinized and none were attributable to an extraterrestrial source.Comment: 15 pages, 5 figures, accepted for publication in the Astronomical Journa

Determination of the degree of gelatinization of starch

Digitized by Kansas Correctional Industrie

Friction dependence of reaction rates in simple barrierless reactions

We have investigated the dynamics of simple chemical reactions which proceed without an activation barrier along the reaction coordinate. In the absence of the barrier the solvent friction is the only impediment to the reactive motion. By numerical simulation we show that in the low-friction limit the reaction rate increases as a fractional power of the friction coefficient. The power law dependence is sensitive to the initial conditions of the reactive coordinate. After exhibiting a maximum, the behaviour crosses over to that of inverse friction dependence in the high-friction limit. We have compared our results with earlier approximate analytical treatments and differences are pointed out

Limnological studies on Yellamallappa Chetty Lake, Bangalore, Karnataka

Water quality plays an important role in the survival and distribution of aquatic organisms. It is dependent on physicochem. and microbiol. parameters. Yellamallappa Chetty Lake (YCL) has historically clear water and used to supply for the drinking purpose. Local residents explain that water clarity has decreased appreciably in recent years. The study was initiated in response to concern over deteriorating water quality, probability of increased nutrient loading from non point sources and municipal effluents. Water quality data were collected at 8 sampling sites from Feb. 2004 to June, 2004. Noticeable changes in many water quality parameters were obsd. High nutrient concns., the increasing incidence of nuisance algal blooms, and trophic state index values' indicate that it can be currently classified as Eutrophic

Magnetic hardening mechanism in nanocrystalline Nd2Fe14BNd_2Fe_{14}B with 0.1 at. % addition of Cr, Cu, or Zr

The nanocrystalline hard magnetic Nd2Fe14B phase plays a crucial role in the development of exchange spring magnets. We report the hardening mechanism of nanocrystalline Nd2Fe14B, as well as the effect of small amounts of magnetic additions on the hardening behavior. It is shown that the hardening mechanism is of the pinning type in the pure Nd2Fe14B phase. Retention of pinning-type behavior, with a marginal increase in coercivity was observed for small additions of Cr or Cu. Addition of Zr changes the mechanism to nucleation type with a decrease in coercivity. Additions of Zr or Cu are thought to form precipitates at grain boundaries. The precipitates containing Cu were found to be effective in pinning the domains and enhancing the coercivity. The Zr-containing precipitates were found to be ineffective in pinning the domain walls and act as nucleation centers for reverse domains, resulting in nucleation-type hardening. The magnetic behavior of Cr-containing samples above the Neel temperature of Cr remains unaltered. This lack of change in the Cr-containing samples combined with the observed lowering of remanence indicates the presence of Cr in solution with Nd2Fe14B. Thus, we conclude that not only the magnetic nature of the impurity, but also its location is important in controlling the coercivity mechanism

Evaluation of physico-chemical and coliform variations in different locations of Yellemallapa Chetty Lake (YCL) located in Silicon city (Bangalore District) Karnataka, India

Physico-chemical and coli form counts have been studied in the Yellemallappa Chetty Lake during summer season (February 2004 to June 2004) to evaluate lake water quality for Fish culture, Irrigation and for Recreational purposes. The three different locations were selected for variation studies, namely (i). Inlets of the lake (ii). Within the lake and (iii). Outlets of the lake, and a total of 18 parameters were studied in all the three locations. Based on the Carlson's status indices the lake was classified as eutrophic during the study period. Other pameters were in normal range but show drastic changes from month to month and location to location. © Global Science Publications

Magnetic hardening mechanism in nanocrystalline Nd<SUB>2</SUB>Fe<SUB>14</SUB>B with 0.1 at. % addition of Cr, Cu, or Zr

The nanocrystalline hard magnetic Nd2Fe14B phase plays a crucial role in the development of exchange spring magnets. We report the hardening mechanism of nanocrystalline Nd2Fe14B, as well as the effect of small amounts of magnetic additions on the hardening behavior. It is shown that the hardening mechanism is of the pinning type in the pure Nd2Fe14B phase. Retention of pinning-type behavior, with a marginal increase in coercivity was observed for small additions of Cr or Cu. Addition of Zr changes the mechanism to nucleation type with a decrease in coercivity. Additions of Zr or Cu are thought to form precipitates at grain boundaries. The precipitates containing Cu were found to be effective in pinning the domains and enhancing the coercivity. The Zr-containing precipitates were found to be ineffective in pinning the domain walls and act as nucleation centers for reverse domains, resulting in nucleation-type hardening. The magnetic behavior of Cr-containing samples above the Neel temperature of Cr remains unaltered. This lack of change in the Cr-containing samples combined with the observed lowering of remanence indicates the presence of Cr in solution with Nd2Fe14B. Thus, we conclude that not only the magnetic nature of the impurity, but also its location is important in controlling the coercivity mechanism

The Nature of Ordered Structures in Melt Spun Iron-Silicon Alloys

Increasing the silicon content is known to improve the magnetic properties of iron-silicon alloys (I). However, the associated loss of ductility has prevented the use of high silicon alloys in practical applications. The melt spinning of high silicon alloys can,produce wide tapes with reasonable ductility that are now regarded as one of the promising materials for magnetic applications (2-8). Investigations of the magnetic and mechanical properties consistently indicate a variation with silicon content (2- , 8-II). The best property combinations seem to exist for 6.5 wt % silicon alloy. Narita and Enokizono (10) have shown that in bulk Fe-Si alloys with high silicon contents, the B2 and $DO_3$ ordering lead to different property changes and that cooling rate has major influence on magnetic properties. The magnetic and mechanical properties of rapidly solidified melt spun alloys are shown to be significantly different (3-5,7- 10-12). For example, the permeability of melt spun tapes is different for different alloys. It has a maximum value for a 6.5 wt % Si alloy which is different behavior from that observed in a well annealed sample (12). In order to understand the reasons for such behavior, a clear understanding of the structure is necessary. There exists considerable confusion in the literature regarding the structure of the melt spun alloys (3-5,7-8,13). For example, $DO_3$ ordering is assumed to be predominant in melt spun 6.5 wt %'SJ alloy by many investigators (4-7). Chang et al. (5) have presented TEM evidence of it Jn the shape of a 010 superlattice spot observable Jn a [100] zone selected area diffraction pattern. However, this is not adequate to differentiate between the B2 and $DO_3$ ordering. A different conclusion that the structure is a predominantly disordered phase (A2) with a very small amount of B2, was reported by Enokizono et al. (3). They have also reported the absence of domain structure. Guntherodt (7) and Warlimont (8) highlighted the suppression of the ordering reaction by melt spinning as the main reason for the improved ductility of the melt spun tapes

Role of Polymer Interactions with Clays and Modifiers on Nanomechanical Properties and Crystallinity in Polymer Clay Nanocomposites

We present the effect of organic modifier on crystallinity and nanomechanical properties of polymer clay nanocomposites (PCNs) using two different polymers while maintaining the same nanoclay and organic modifier. Experimental results and interaction energy maps of Polybutylene-Terephthalate- (PBT-) PCN system indicate that the underlying mechanisms of change in crystallinity and improvement in mechanical properties as proposed in altered phase theory are valid. Experimental and molecular simulation studies of PBT-PCN and Nylon6-PCN reveal that a higher crystallinity polymer could require significantly higher attractive and repulsive interaction energies between polymer and organic modifiers to change the crystallinity of the polymer in the PCN significantly and thus improve mechanical properties of the PCN

The nature of ordered structures in melt spun iron-silicon alloys

Increasing the silicon content is known to improve the magnetic properties of iron-silicon alloys (I). However, the associated loss of ductility has prevented the use of high silicon alloys in practical applications. The melt spinning of high silicon alloys can,produce wide tapes with reasonable ductility that are now regarded as one of the promising materials for magnetic applications (2-8). Investigations of the magnetic and mechanical properties consistently indicate a variation with silicon content (2- , 8-II). The best property combinations seem to exist for 6.5 wt % silicon alloy. Narita and Enokizono (10) have shown that in bulk Fe-Si alloys with high silicon contents, the B2 and DO3 ordering lead to different property changes and that cooling rate has major influence on magnetic properties. The magnetic and mechanical properties of rapidly solidified melt spun alloys are shown to be significantly different (3-5,7- 10-12). For example, the permeability of melt spun tapes is different for different alloys. It has a maximum value for a 6.5 wt % Si alloy which is different behavior from that observed in a well annealed sample (12). In order to understand the reasons for such behavior, a clear understanding of the structure is necessary. There exists considerable confusion in the literature regarding the structure of the melt spun alloys (3-5,7-8,13). For example, DO3 ordering is assumed to be predominant in melt spun 6.5 wt %'SJ alloy by many investigators (4-7). Chang et al. (5) have presented TEM evidence of it Jn the shape of a 010 superlattice spot observable Jn a [100] zone selected area diffraction pattern. However, this is not adequate to differentiate between the B2 and DO3 ordering. A different conclusion that the structure is a predominantly disordered phase (A2) with a very small amount of B2, was reported by Enokizono et al. (3). They have also reported the absence of domain structure. Guntherodt (7) and Warlimont (8) highlighted the suppression of the ordering reaction by melt spinning as the main reason for the improved ductility of the melt spun tapes