Synthesis and optoelectronic properties of hexa-peri -hexabenzoborazinocoronene

The first rational synthesis of a BN-doped coronene derivative in which the central benzene ring has been replaced by a borazine core is described. This includes six C−C ring-closure steps that, through intramolecular Friedel–Crafts-type reactions, allow the stepwise planarization of the hexaarylborazine precursor. UV/Vis absorption, emission, and electrochemical investigations show that the introduction of the central BN core induces a dramatic widening of the HOMO–LUMO gap and an enhancement of the blue-shifted emissive properties with respect to its all-carbon congener

Polymorphism, Fluorescence, and Optoelectronic Properties of a Borazine Derivative

EU, FRS-FNRS. Grant Numbers: 2.4.550.09, F.4.505.10.F, Belgian Government. Grant Numbers: P06-27, 09/14-023, University of Namur, FRIA, Italian National Research Council. Grant Number: PM.P04.010, European Commission. Grant Number: 238177, Belgian National Fund for Scientific Research (FNRS

Karst features on the Withlacoochee River, near Valdosta, Georgia

The Withlacoochee River of South Georgia crosses an area of karst landscape before it flows south into the Suwannee River in Florida. This limestone karst is particularly well-developed ~5 km northwest of Valdosta Georgia. At this location the Withlacoochee River crosses an area of widespread sinkhole development. Some of these sinkholes occur directly in the riverbed. Field studies by both the USGS and by faculty at Valdosta State University have shown that during periods of intense drought the water in the Withlacoochee River is completely consumed as 100% of the water flows into the sinks. Additionally, a small segment of the downstream portion of the river reverses flow and flows north into the sink area. When the river is at drought conditions many karst features can be observed both in and near the dry Withlacoochee channel. These karst features include disappearing streams, solution cavities, whirlpools, sinkholes, and caves. This also provides an excellent opportunity to observe conventional stream landforms such as channel features, depositional features, and flow features. During periods of higher rainfall, the Withlacoochee will return to normal flow. The USGS has studied groundwater flow in this are and has found that significant and rapid communication exists between the river and the underlying aquifer systems, including the important Floridan Aquifer

SUMMARY OF UNDERGRADUATE RESEARCH ACTIVITIES ON PEGMATITES IN THE NORTHCENTRAL GEOGIA BLUE RIDGE**

Many felsic pegmatites occur in the Blue Ridge of northcentral Georgia. These pegmatites are known from earlier studies, but those studies predated current tectonic models for this area. Several undergraduate research projects sponsored by Valdosta State University have focused on these pegmatites to relate their occurrence with modern tectonic models. The findings of this on-going effort include: Most of the pegmatites are simple pegmatites (quartz, muscovite, feldspar), likely the result of prograde metamorphic processes (aka “metamorphic sweats”). At least two of the pegmatites show complex mineralogy (beryl, ± columbite-tantalite, ± garnet, ± tourmaline) and this suggests they are of different origin than the simple pegmatites (aka “complex pegmatites”). The pegmatites occur in three clusters, a group located on both sides of the Allatoona Fault near Canton, Georgia, A group north of the Allatoona Fault near Ball Ground, Georgia, and a group clustered on both sides of the southern terminus of the Hayesville Fault. The current studies did not focus on the Haysville Fault group. Pegmatite clusters correspond with areas of higher-grade metamorphism and pegmatites have not been found in areas of low-grade metamorphism. The two pegmatites that are interpreted as complex occur in the Ball Ground area within the Western Blue Ridge. Most of the pegmatites are parallel or sub-parallel to metamorphic foliation, although small-scale crosscutting veins are common. Most of the pegmatites were excavated during WWII as part of a nation-wide mica exploration program. The work here includes several pegmatites that were not previously identified. Importantly, these pegmatites appear to be synmetamorphic and their distribution appears to crosscut both the Allatoona Fault and the Hayesville Fault suggesting both faults were premetamorphic