Using synchrotron radiation to study iron phases in Saharan dust samples from Athens skies

The Sahara desert is the largest source of dust in the world. Saharan dust is characterized by great com- plexity, composed mainly of mixtures of mineral phases (amorphous or crystalline, with particle sizes of the order of μm or even nm). The presence of amorphous components makes it difficult to detect their struc- ture. For this purpose the spectroscopic technique of X–ray absorption fine structure μ–XAFS combined to ultrabright synchrotron SR microbeams is suitable. SR’s main advantage is the recording of spectra in a very short time. In this paper we focus on the study of forms of iron deposited on southeast Mediterranean Sea and mainland of Greece by the waves of Saharan dust. Data collection was carried out at the premises of ANKA (KIT, Germany) on the beamline SUL–X of the environmental research laboratory with advanced X–ray spectroscopic techniques, μ–XRF, μ–XRD and μ–XAFS. Results from the measurements and the simulated spectrum are presented.

Investigation of heat transfer in a triple-glazing type window at greek climate conditions

Heat loss through building windows has a major effect on the energy efficiency of the buildings. The window studied in this paper is a triple-glazing type window pane in which spaces contain dry air. The window is placed in a specially developed test chamber at the Energy and Environmental Research Laboratory of Central Greece University of Applied Sciences at Chalkida. At one side of the test chamber variable temperature environment for different temperature waving scenarios (20–30°C, 25–35°C, 20–35°C) adequate for Greek climate and at the other side steady constant temperature environment (20°C, 25°C) representing indoors conditions were created. Glass surface temperatures at both sides of the tested window pane and heat flux through it were measured. For triple-glazing thermal transmittance calculation a model of equations in visual basic was developed which accounts for the equations of conduction, convection and radiation in every layer of window pane. A sufficient agreement between the experimental results and the results of the model is noticed.

Groundwater Plume Mapping in a Submerged Sinkhole in Lake Huron

A multidisciplinary exploratory project team from the Institute for Exploration, the Great Lakes Environmental Research Laboratory, Grand Valley State University, and the University of Michigan located and explored a submerged sinkhole in Lake Huron during September 2003. A CTD system and an ultra-short baseline (USBL) acoustic navigational tracking system integrated with an open frame remotely operated vehicle (ROV) provided high-resolution depth, temperature, and conductivity maps of the sinkhole and plume. Samples were also peristaltically pumped to the surface from a depth of 92 meters within and outside of the sinkhole plume. A 1-2 m thick cloudy layer with a strong hydrogen sulfide odor characterized the water mass close to the plume. Relative to ambient lake water, water samples collected within this layer were characterized by slightly higher (4-7.5 °C) temperatures, very high levels of chloride and conductivity (10-fold) as well as extremely high concentrations of organic matter (up to 400 mg C/L), sulfate, and phosphorus. Our observations demonstrated the occurrence of unique biogeochemical conditions at this submerged sinkhole environment.

Bacterial Populations in a Biological Nutrient Removal Plant

Research in the area of bacteriological studies of biogical nutrient removal (BNR) systems has emphasized the role of Acinetobacter spp. in phosphorus removal. The present study was undertaken to enumerate, isolate and identify bacterial populations from a BNR/activated sludge system. The most probable numbers (MPN) of volatile fatty acid (VFA) utilizers and denitrifiers were determined. Bacterial populations were isolated from the MPN tubes. Pure cultures of Gram-negative bacteria were identified. Acinetobacter spp. were not the dominant group of bacteria recovered from the system. Bacteria belonging to Aeromonas/Vibrio, coliforms, Pseudomonas and Acinetobacter groups were recovered both on VFA media and denitrification medium, indicating an overlap in their role. In the system studied, both phosphorus and nitrogen removal was carried out by more than one group of bacteria. 1Corresponding Address: The U.S. EPA, Environmental Research Laboratory, 1 Sabine Island Drive, Gulf Breeze, FL 32561. USA