On the Crystallization of Terbium Aluminium Garnet

Attempts to grow terbium aluminium garnet (Tb3Al5O12, TAG) by the Czochralski method lead to crystals of millimeter scale. Larger crystals could not be obtained. DTA measurements within the binary system showed that TAG melts incongruently at 1840 deg. C. The perovskite (TbAlO3, TAP) with a congruent melting point of 1930 deg. C is the most stable phase in this system. The region for primary crystallization of TAP covers the chemical composition of TAG and suppresses the primary crystallization of the terbium aluminium garnet.Comment: 6 pages, 2 figure

Phase diagram analysis and crystal growth of solid solutions Ca_{1-x}Sr_xF_2

The binary phase diagram CaF$_2$--SrF$_2$ was investigated by differential thermal analysis (DTA). Both substances exhibit unlimited mutual solubility with an azeotropic point showing a minimum melting temperature of T_\mathrm{min}=1373^{\circ}$C for the composition Ca$_{0.582}$Sr$_{0.418}$F$_2$. Close to this composition, homogeneous single crystals up to 30 mm diameter without remarkable segregation could be grown by the Czochralski method.Comment: accepted for publication in J. Crystal Growt

A Cultural Resources Survey for the Leon Valley Hike and Bike Trail Project, Bexar County, Texas

In early March, 2014, South Texas Archeological Research Services, LLC, conducted a cultural resources survey for the Leon Valley Hike and Bike Trail Project, Bexar County, Texas. The survey focused on discovery and preliminary assessment of archeological resources but also included an estimation of effect to the Huebner-Onion Homestead and Stage Coach Stop Site (41BX1429), which was listed in the National Register of Historic Places. Since the project area was owned by the City of Leon Valley and the project involved federal funding through the Texas Department of Transportation, compliance with the Antiquities Code of Texas and Section 106 of the National Historic Preservation Act was triggered for the project. The survey was conducted according to applicable professional standards and guidelines under Texas Antiquities Permit 6803. Portions of the project area that were previously investigated were not included in the survey, and portions of the area were revised or omitted after completion of the survey. The project, as ultimately revised, consisted of replacement of existing trails, additions of new trails, and construction of concrete bridges at three creek crossings. Not including portions previously examined, the final revised footprint of the area of potential effects to cultural resources for the project was about 1.6 acres of trail rightof-way about 3,500 feet long and 20 feet wide. Except at the creek crossings, where some deeper cutting and filling would be needed, the average anticipated depth of impact for the project was about 6-12 inches. The area of potential effects for indirect effects to non-archeological cultural resources was the area within about 100 feet of the final proposed trail routes not previously surveyed. Background searches revealed that except for prehistoric archeological site 41BX1879, found near the project area in 2012 and later determined ineligible, and the Huebner-Onion Site, no cultural resources were within a kilometer radius of the survey area. Field conditions within most of the area surveyed precluded effective visual surface examination, but patchy surface exposures in the uplands and exposed profiles along Huebner Creek were inspected. Because of shallow soils within most of the area and access limitations, archeological backhoe trenching was neither feasible nor warranted. Sixteen archeological shovel tests were excavated throughout the survey area. Shallow clay soils over limestone or caliche bedrock, or dense clay substrate, were encountered in most of the tests. No archeological evidence was found during the survey and nothing was collected or curated. The Principal Investigator believed that construction of the proposed trail, as finally revised, should not affect any archeological resources. Based on the research and findings a consulting architectural historian and on all revisions to the project plans made to time of this report in June, 2014, the Principal Investigator and architectural historian believed that the project would have no adverse effect on the Huebner-Onion Site. A local historical icon within the survey area, the marker for the presumed gravesite of prominent nineteenth-century settler and stockman Joseph Huebner (1823-1882), was neither listed nor eligible as a landmark. In May, 2014, the segment of the proposed trail leading from the main east-west trail southward to the marker was omitted from the project by the City of Leon Valley, thereby obviating the need for further cultural resource investigations for that segment. Prior to omission, visual inspection and excavation of two archeological shovel tests within the footprint of the segment found no cultural evidence. It was recommended to the City of Leon Valley and its consultants, the Texas Historical Commission, and the Texas Department of Transportation that the project as revised should proceed without further archeological or other cultural resource compliance work, except in the event that cultural resources not found during the survey were found during project-related construction activities. Per applicable statutes and regulations, it was also recommended that in the event of such finds, work should immediately be halted in the vicinity until the finds were examined and evaluated by a qualified archeological consultant and/or the Commission and the Department

Archaeological Survey Of The Nolan Creek Improvements For The City Of Belton, Bell County, Texas

In September 2013, American Archaeology Group LLC conducted an archaeological survey of three tracts of land along Nolan Creek totaling 8.68 acres for the City of Belton’s planned low water dam removal and replacement dam installed, development of a parking lot and trail for kayakers, and removal of a low water bridge crossing. These improvements are being funded by a Texas Parks & Wildlife Department grant. The investigation consisted of a pedestrian survey supported with mechanical trenching. No archaeological sites were identified during the survey. American Archaeology Group LLC recommends that construction within the project area should be allowed to proceed as planned without archaeological monitoring. No artifacts were recovered; therefore, no curation was arranged

Growth of Oxide Compounds under Dynamic Atmosphere Composition

Commercially available gases contain residual impurities leading to a background oxygen partial pressure of typically several 10^{-6} bar, independent of temperature. This oxygen partial pressure is inappropriate for the growth of some single crystals where the desired oxidation state possesses a narrow stability field. Equilibrium thermodynamic calculations allow the determination of dynamic atmosphere compositions yielding such self adjusting and temperature dependent oxygen partial pressures, that crystals like ZnO, Ga2O3, or Fe{1-x}O can be grown from the melt.Comment: 4 pages, 3 figures, talk on CGCT-4 Sendai, May 21-24, 200

Archaeological Monitoring Of The Histroric Gan\u27s Dam At Berry Creek Preserve For The Williamson County Parks Department, Williamson County Parks Department, Williamson County, Texas

Archaeological monitoring of repairs to the historic Gan’s Dam, previously recorded as one historic component of archaeological site (41WM17), was conducted October 2-12, 2013 at the Berry Springs Preserve in Williamson County, Texas. Previous storm damage caused the dam to fail and impounded pond waters pushed the surface portion of the historic dam downstream. Williamson County Parks Department contracted with a construction firm to make repairs to the dam. Consequently, AAG was contacted about the discovery of the subsurface old historic dam limestone blocks and this led to discussions with the Texas Historical Commission, Archeology Division, and with the U.S. Army Corps of Engineers (COE), Fort Worth District. Subsequently, a Texas Antiquities Permit (6674) for monitoring was obtained and all work was also conducted under the auspices of Section 106 of the National Historic Preservation Act. Construction resumed with AAG on-site to ensure that the remnant historic dam features were not disturbed. The remaining dam portions were encapsulated with cement to provide a strong retention dam and to provide for long-term preservation of the historic dame and any potential remaining cultural deposits. No artifacts or features were encountered during monitoring, therefore, only project records are curated at the Center for Archaeological Research at the University of Texas at San Antonio

Refinement of the crystal structure of praseodymium orthoscandate, PrScO3

O3PrSc, Prima (no. 62), a = 5.780(1) Å, b = 8.025(2) Å, c = 5.608(1) Å, V= 260.1 Å3, Z = 4, R gr(F) = 0.025, wRref(F2) = 0.060, T= 298 K. © by Oldenbourg Wissenschaftsverlag, München

Crystal structure of distrontium praseodym gallium pentaoxide, Sr2PrGaO5

GaO5PrSr2, tetragonal, I4/mcm (No. 140), a = 6.8441(2) Å, c = 11.2534(4) Å, V = 527.1 Å3, Z = 4, R(P) = 0.035, wR(P) = 0.052, R(I) = 0.038, T = 295 K. © by Oldenbourg Wissenschaftsverlag

Refinement of the crystal structure of praseodymium orthoscandate, PrScO3

O3PrSc, Prima (no. 62), a = 5.780(1) Å, b = 8.025(2) Å, c = 5.608(1) Å, V= 260.1 Å3, Z = 4, R gr(F) = 0.025, wRref(F2) = 0.060, T= 298 K. © by Oldenbourg Wissenschaftsverlag, München