Alpha-U has been observed to undergo the following sequence of transformations at T 0 < 43K (lower limit of stability of the structure) a transition involving modes for which q CDW = < q x , q y , q z >; ortho.: Cmcm T 0 = 43K > mono.: C2/m11 (q x , q y , q z) T 1 = 37K > mono.: P211 (1/2, q y , q z). The phonon dispersion was measured by neutron inelastic scattering in the range (200, 43K) of existence of the high-temperature orthorhombic phase and in the range of the phase transformations at 43, 37 and 22K. Soft branches were associated with the normal-to-incommen-surate transitions in Brillouin zone: (201). The main component of the displacement pattern is consistent with the symmetry for a Σ 4 phonon mode. The static displacements associated with the displacive transition are produced by low-frequency and damped phonons at positions q s [(q x , q y , q z)] which on approaching the second-order phase transition (T 0) soften more than those with q c = [1/2, 0, 0], but not totally. Increasing the energy resolution by using cold neutrons on the three axis spectrometer IN14 near (101), we have seen in the range T-T 0 = 7K a small deviation from the linear law of Curie. The experimental phonon softening [1] which is accompanied by large changes in cell parameters at T 0 , is dependent on q y (T), q z (T) contrary to predictions of the Yamada theory. At T 0 = 43 K the modulation wave vector of the incommensurate low-temperature condensing soft mode is q min = [0.497 (1), 0.13 (1), 0.21 (1)] (q CDW. The electronic instability which causes Kohn anomaly also triggers the displacive (Peierls) transition. Relaxors are special class of ferroelectrics that exhibit a broad, diffuse phase transition over a temperature range and a strong frequency dependence of the dielectric constant as a function of temperature. Near room temperature they exhibit very high dielectric permittivity, electrostrictive and electrooptical coefficients , which determine relaxors as multi-functional materials, with a wide range of technological applications, including non-volatile memory devices. The global, average structure of relaxors, detectable by diffraction methods, remains pseudo-cubic even at liquid helium temperatures, whereas their nanoscale structure is rather complex. Near the Curie range and under zero-field conditions the ferroic clusters are sized only a few unit-cell parameters and they create and annihilate within 10-5-10-6 s. Thus, because of its length-and timescale sensitivity, inelastic light scattering is vital for gaining structural information. The mechanism of paraelectric-to-relaxor ferroelectric phase transition is still not clarified. To better understand the local structural phenomena occurring in relaxors we have applied Raman scattering and X-ray diffraction on single crystals of stoichiometric PbSc 0.5 Ta 0.5 O 3 (PST), solid solutions of type PbSc 0.5 Ta .5 O 3-PbSc 0.5 Nb .5 O 3 and PbSc 0.5 Ta .5 O 3-PbSnO 3 , A-site mixed (Pb 1-x A'' x)Sc 0.5 Ta 0.5 O 3 (A'' = Ba,), as well as Ru-doped PbSc 0.5 Ta 0.5 O 3. The ...

Two approaches, irrigation with impaired waters, and use of subsurface drip irrigation, have been identifi ed as strategies to reduce the use of potable water for landscape irrigation. A study was conducted at New Mexico State University in Las Cruces in 2008 and 2009 to investigate the establishment of Princess 77 bermudagrass [Cynodon dactylon (L.)] and Sea Spray seashore paspalum [Paspalum vaginatum (Sw.)] seeded in March (dormant) or June (traditional). Th e grasses were irrigated at 98% reference evapotranspiration with saline [electrical conductivity (EC) = 2.3 dS m -1 ] or potable (EC = 0.6 dS m -1 ) water from either a sprinkler or a subsurfacedrip system. Establishment did not diff er between the two grasses regardless of seeding date, irrigation type, or water quality. Generally, grasses that were seeded dormant reached 75% cover faster and exhibited greatest ground cover at the end of both growing seasons. When data were averaged over water qualities and seeding dates, sprinkler irrigation resulted in greater ground cover (90% in 2008 and 92% in 2009) than drip irrigation (58% in 2008 and 80% in 2009) at the end of both research periods. Highest EC levels at rootzone depths of 0 to 10 cm were observed in November 2009 on plots drip irrigated with saline water, averaging 4.4 dS m -1 compared to 2.3 dS m -1 on sprinkler irrigated plots. Our results indicate that when using subsurface-drip irrigation, early seeding is required to successfully establish seashore paspalum and bermudagrass from seed in one growing season.New Mexico State Univ., Las Cruces, NM 88003.

A study was conducted at New Mexico State University in Las Cruces, NM, from 2010 to 2012 to investigate the effects of deficit irrigation on bermudagrass (Cynodon dactylon L.) cultivar Princess 77 and seashore paspalum (Paspalum vaginatum Swartz) cultivar Sea Spray treated with either soil surfactants [Revolution (modified methyl capped block copolymer) or Dispatch (alkyl polyglucoside blended with a straight block copolymer)] or a plant growth regulator [Trinexapac‐ethyl (TE); 4‐(cyclopropylhydroxymethylene)‐3,5‐dioxocyclohexanecarboxylic acid]. Irrigation was applied daily at 50% reference evapotranspiration from either a sprinkler or a subsurface drip system with either potable (electrical conductivity [EC] = 0.6 dS m−1) or saline (2.3 dS m−1) water. Normalized Difference Vegetation Index (NDVI) and visual ratings were determined monthly to assess stand quality and turf stress. Princess 77 treated with TE showed the highest quality and the highest NDVI (0.655) on 10 out of 15 sampling dates. Positive effects of TE applications were also observed on Sea Spray quality, NDVI, and fall color retention. Subsurface drip irrigation resulted in higher quality and NDVI during the third year of the study when compared with sprinkler irrigation. Salinity buildup in the root zone did not negatively affect visual quality of the tested warm‐season species. Generally, sprinkler irrigation system and turf treated with Revolution promoted higher water distribution uniformity (lower standard deviations) than the other treatments. Further research is needed to investigate if greater drought tolerance of subsurface drip–irrigated turf is the result of increased water‐use efficiency due to altered root morphology.