Reuse and air classification of bioash

The amount of biomass ash (BA) produced worldwide is expected to increase in the near future because biomass is commonly regarded as a carbon neutral fuel. Therefore, sustainable methods for the utilization of BA will be needed to manage the increased flux of BA from the energy sector while concurrently dealing with a smaller allowance of BA that can be landfilled. Therefore, research into new technologies is needed to find and exploit methods to utilize BA in safe and economically and environmentally sustainable ways in order to maximize the environmental benefits of biomass combustion. Presently BAs are utilized primarily in the construction of landfills or disposed of in landfills, with a minor percentage recycled for various purposes. Viable alternatives to landfill construction and landfill disposal require supportive evidence for their practicality, which is currently limited. One of the main barriers to reuse is the presence of heavy metals in BA. Therefore, finding effective methods for isolating and removing heavy metals is important to allowing reuse and is pursued in this work. Furthermore, this thesis seeks to assess the quality of specific BA samples as the quality pertains to their final usage, and to assess the sustainability of the usage solution to the comparable product that BA is replacing. Technologies were evaluated for their suitability and feasibility for utilizing BA as a replacement for traditional natural resources in specific applications. This thesis will seek to clarify the usage of air classification for refining BA for reuse as a product with the goal of contributing to the knowledge of viable and sustainable solutions for the reuse of BA. Background information on the quantities, quality, formation, analytical methods, utilization options, treatment methods and law and regulation related to BA were investigated prior to the experimental design. Based on that research and the interests of Ekokem, evaluation of three BA samples for reuse in agriculture, earth construction, cement and landfill disposal was completed. Additionally, air classification tests were performed on the BA samples with the objective of isolating certain components of the BA in a separate fraction; those samples were also evaluated for the same reuse schemes. The experiments produced three types of results. First was the procedure development in how to carry out air classification experiments and results directly related to air classification that can guide future research. Second were the results for individual samples and their reuse potential; one sample showed reuse possibilities without refining; the two other samples showed some improvements through air classification with isolation of heavy metals in the fine air classified fraction. Lastly, challenges experienced and additional work related to the reuse of BA and air classification experiments were outlined

Molecular recognition in synthetic systems: I. Rigidified dendritic systems for imparting enantioselective molecular recognition to platinum-containing molecularly imprinted polymers II. Using laser polarimetry to identify an enantioselective receptor for (-)-adenosine from a racemic dynamic combinatorial library

The understanding of molecular recognition events is of great importance to current chemical research. This work documents two examples of molecular recognition in synthetic systems. Molecularly imprinted polymers containing platinum have been synthesized that can differentiate between enantiomers in a ligand exchange reaction. The use of laser polarimetry as a method to detect enantioselective interactions in a racemic dynamic combinatorial library is also described. Platinum-containing molecularly imprinted polymers (MIPs) were synthesized by the covalent incorporation of polymerizable P2Pt((S)-BINOL) metallodendrimers constructed with a rigid phenyl benzoate ester linkage into a highly-porous and cross-linked methacrylate-based polymer. The enantioselectivity of the polymer with respect to BINOL ligand exchange reactions was studied and compared to similar polymers prepared from metallodendrimers containing a conformationally flexible phenyl benzyl ether linkage. The rigidity of the ester linkage resulted in higher enantioselectivities for a BINOL/Br2BINOL ligand exchange reaction as compared to the ether linkage. The most selective polymer exchanged (±)-Br2BINOL for (S)-BINOL at the platinum sites with an enantioselectivity of 82:18 which equals the highest observed for these polymers. At elevated temperatures preferential deactivation of the less hindered, and therefore less selective sites, is observed due to the thermolytic cleavage of the BINOL ligand. These polymers exhibit enantioselective molecular recognition for the imprinted enantiomer of BINOL through outer-sphere control by the polymer matrix. The study of laser polarimetric detection for the analysis of dynamic combinatorial libraries comprised of racemic compounds was undertaken in an effort to identify enantioselective molecular recognition. An enantioselective receptor for the biologically important molecule (-)-adenosine was identified in this manner. This demonstrates a novel and efficient method for the study of enantioselective molecular recognition in synthetic systems. The use of deuterium-labeled species was developed as a method for identifying the stereochemistry of the receptor of interest by mass spectrometry. This method was also used to quantify the diastereomeric composition of a library component. This work proves that used together in this manner, laser polarimetry, dynamic combinatorial chemistry, and mass spectrometry are powerful strategies for the continued study of enantioselective molecular recognition

Thermal and Photo Sensing Capabilities of Mono- and Few-Layer Thick Transition Metal Dichalcogenides

Two-dimensional (2D) materials have shown promise in various optical and electrical applications. Among these materials, semiconducting transition metal dichalcogenides (TMDs) have been heavily studied recently for their photodetection and thermoelectric properties. The recent progress in fabrication, defect engineering, doping, and heterostructure design has shown vast improvements in response time and sensitivity, which can be applied to both contact-based (thermocouple), and non-contact (photodetector) thermal sensing applications. These improvements have allowed the possibility of cost-effective and tunable thermal sensors for novel applications, such as broadband photodetectors, ultrafast detectors, and high thermoelectric figures of merit. In this review, we summarize the properties arisen in works that focus on the respective qualities of TMD-based photodetectors and thermocouples, with a focus on their optical, electrical, and thermoelectric capabilities for using them in sensing and detection

Estimation of the Percent of Unique Population Elements on a Microdata File Using the Sample

This series contains research reports, written by or in cooperation with staff members of the Statistical Research Division, whose content may be of interest to the general statistical research community. The views reflected in these reports are not necessarily those of the Census Bureau nor do they necessarily represent Census Bureau statistical policy or practice. Inquiries may be addressed to the author(s) or the SRD Report Serie