Abstract to“Interfacial colloidal particle films andtheir structure formation”; a licentiate thesis, whichwill be presented by Sandra Rödner in Q2, 29 November 2002at 13.00. Colloidal particles can be made to organise themselves intoordered arrays. These colloidal structures acquire interestingand useful properties, not only from their constituentmaterials but also from the spontaneous emergence of mesoscopicorder that characterises their internal structure. Orderedarrays of colloidal particles, with lattice constants rangingfrom a few nanometers to a few microns, have potentialapplications as optical computing elements and chemicalsensors, and also has an important influence on the mechanicalproperties and optical appearance of paint films and papercoatings. The control of colloidal structure formation starts with theparticle interactions (attractive or repulsive) and colloidaldynamics, which is the topic of this thesis. To enable adetailed understanding of the different factors that controlthe formation of dense 2D colloidal films, a method forstructural characterisation was developed. The degree of orderin the hexagonal close-packed structure, displayed by thecolloidal films, was characterised by the size of ordereddomains and by the distribution of pore sizes. The size ofordered domains was obtained from the pair distributionfunction, and the distribution of pores from a Delaunaytriangulation procedure. These methods are based on theparticle positions in the film, which were determined by lightmicroscopy and processed digital images. The two methods were used to study the effect of particleinteractions on the structure of colloidal monoparticulatefilms, formed at the air-liquid interface. The size of theordered domains decreased exponentially with increasing bondstrength, while the pore density increased. The transfer andsubsequent drying of the formed film on a solid substrateinduced structural changes; the capillary forces transformedsmall pores into triangular order while some of the largervoids and cracks increased in size. The structural features of colloidal monolayers, formed bydrying a dilute silica suspension on a substrate, wereinvestigated. Addition of small amounts of salt resulted indrastic changes of the particle film structure. The size of theordered domains decreased exponentially with increasing amountsof added salt (0-2.9% NaCl/Silica ratio), with a simultaneousincrease of the concentration of large defects. This suggeststhat loss of colloidal stability and onset of particle adhesionto the substrate inhibit rearrangement and ordering. Theevaporation rate was controlled by varying the relativehumidity during drying. Colloidal monolayers with the largestordered domains and the lowest concentration of stacking faultswere formed at an intermediate humidity (55% RH). The rearrangement process during drying of dilute silicasuspensions was followed in detail by studying the changes inthe structural features during growth of colloidal monolayers.Low crystal growth rate promoted the transition of squarelattice domains to a hexagonal close-packed structure. Additionof salt to the electrostatically stabilised dispersionincreased the formation of square structured regions at thecrystal-suspension interface, due to increasing adhesion to thesubstrate. The loss of colloidal stability inhibited therearrangement process, resulting in higher concentrations ofsquare lattice domains at large distances from the crystal edgecompared to systems without added salt. / NR 20140805

I en tid där begreppet hållbarhet är prioritet i flera frågor får det en att fundera på vad hållbarhet är och betyder. Vi människor kommer antagligen alltid kämpa med frågor om miljö, konsumtion och hållbarhet, i en ständig kamp för balans. Vi omger oss av mer hushållsartiklar än tidigare och har börjat ifrågasätta hur tillverkningsprocessen ser ut av dessa (Roos. 2020). Vi ställer även krav på försäljare och förväntar oss miljömärkta produkter och garantier och pratar oroligt om hållbarhet. I det här projektet vill jag försöka närma mig saltsten som ett alternativt material. Genom praktiska metoder och experiment vill jag belysa fördelar med ett biobaserat material i produktionen av vardagsföremål. Förhoppningsvis kan ett emotionellt värde väckas i mitt experimenterande med saltsten där materialet är med i utvecklingen som en aktiv deltagare. Jag har valt att utforska ett biomaterial och på vad dess hållbarhet kan vara och inte vara.  Ett utforskande med saltsten kan hjälpa till att sänka visuella förväntningar men också ge en förståelse till materialet på ett djupare och mer unikt sätt. Jag har valt att arbeta med saltsten eftersom salt förekommer rikligt i naturen och jag vill utforska dess styrkor och svagheter som biomaterial. I mitt sökande följer jag funktionen före formen där formen blir mindre viktig och på så sätt hittar jag nya områden för användandet. I vårt konsumtionssamhälle är ordet hållbarhet på tapeten ofta och en undrar huruvida det på riktigt berör oss. Nya material tillåter oss att handla som aldrig förr med gott samvete men är det hållbart för vår natur? Genom produkter av tillfälliga material kan kanske en balans uppnås där en lika lätt kan bli av med en produkt som att kasta en sten i havet.

Thesis advisor: Rudolph Hon / Over 10 million tons of deicers are applied on impervious surfaces during winter storms in the United States every year to create safer driving and walking conditions. Road salt, or sodium chloride, is the most common deicer due to its low price and wide availability. Increasing concentrations of sodium chloride (NaCl) over the past decades have been measured in surface waters and groundwater throughout North America and it is projected to continue increasing. As there are no cost effective alternatives available to road salt, its potential role as an environmental and drinking water contaminant needs to be investigated. Field measurements from previous studies reveal the homogenization of NaCl in the subsurface through consistent elevated levels year-round. Through the integration of field and laboratory methods, this thesis aims to investigate the role of subsurface processes in the transport and pathways of deicers from the point of deposition to eventual emergence in surface waters and its potential impact on drinking water supplies. To understand the contamination pathways of NaCl that result in the observed surface water concentrations, experimental simulations were designed that indicate that gravitational/convective processes are the most important initial processes influencing deicer transport, but that other processes such as diffusion, surface tension, and dispersion/advection also play important roles. / Thesis (MS) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Extensive land areas in arid and semi-arid regions contain excessive amounts of salt which inhibit or prevent the growth of desirable crop plants. This problem is increasing with the development of extensive irrigation projects. The future of irrigation agriculture will depend upon the development and the utilization of means of (1) preventing salt accumulation, (2) reclaiming salted soils. and (3) making the best use of those soils which by reason of drainage problems, soil texture and permeability, poor quality irrigation water, etc. are unsuited for economic reclamation. The utilization of land that is not feasible to completely reclaim, at least under present economic conditions, will depend upon the selection, development, and use of varieties and strains of crop plants which will produce economically under such conditions. The objectives of this research are to (1) test on a preliminary basis the salt tolerance of a number of promising crop plant materials. (2) observe the effect of salt upon plant behavior and growth, and (3) develop various methods of evaluating plant materials for salt tolerance.

No description available.

Dormancy is a plausible strategy for bacteria to overcome the effects of temporal fluctuations in resources or stresses and await more “optimal” conditions to resume metabolic activity and growth. Seasonal changes in environmental conditions force microbes to adjust their metabolic activity accordingly, and community composition drastically shifts. In extreme environments, however, the overriding effects of a constant stress may constrain the need or benefit of bacteria entering dormancy. In hypersaline lakes, high metabolic activity is required to maintain adaptations that permit survival. Sampling from six lakes on a salinity gradient (0.05% – 30.3%), we measured seasonal fluctuations in bacterial dormancy patterns in summer, fall, winter, and spring of 2013-14. Dormancy was calculated based on ratios of OTU recovery between 16S rRNA-based communities (only the active bacteria) and 16S rRNA gene-based communities (all bacteria present in the community) from lake water. Dormancy was linked to lake chemistry shifts through time. We found that salinity was strongly related to relative bacterial dormancy. There was a negative linear relationship (R2 = .89 P <0.01) between total dormancy and salinity. Total phosphorus (R2 = .63, P < .001) and relative community contribution by rare taxa (R2 = .89, P < .001) were also important in structuring dormancy. Our findings suggest that temporal nutrient flux is highly influential on bacterial community composition and activity, but that the presence of an extreme variable decreases change in both through time.

The study of organisms from extreme environments is an emerging field of research with applications to multiple scientific areas. One of these extreme environments is Great Salt Lake (GSL), whose microbiology has yet to be extensively studied. This dynamic and unique environment offers an excellent opportunity to increase understanding of hypersaline ecology. Cultivation of microorganisms remains an important part of ecology research, as it is essential for understanding microbial physiology. We report here the culturing and characterization of isolates from Rozel Point, located on the northeastern shore of Great Salt Lake. This site was chosen because of the presence of petroleum seeps at Rozel Point and the extreme salinity of the North Arm of GSL. We hypothesize that culturing at GSL will reveal a diverse prokaryotic population, with both commonly isolated and novel organisms. We would predict that prokaryotes at GSL will share many features in common with other hypersaline microbial communities, but that given the distinctive properties of the site, there will be unique characteristics as well. Samples were taken from Rozel Point and cultured using direct plating, enrichment cultures, and dilution cultures with a variety of minimal and complex halophilic media. Fluorescence in situ hybridization (FISH) was used to examine abundance of cultured organisms in the environment. Culturing and characterization has revealed both isolates novel and previously uncultured, with many unique characteristics. FISH demonstrated that, unlike most environments, in GSL the dominant species are culturable. These results show the value of culturing in discovering new organisms and demonstrating diversity at the microbial level. Culturing of these organisms will allow for further research to be done on microbial processes that occur in this system and the unique properties of halophilic microbes.

Salt tolerance is a commercially important trait that affects plant species around the globe. Cellular response to saline environments is a well studied but complex system that is far from being completely understood. The SALT OVERLY SENSITIVE 1 (SOS1) gene is a critical component of salt tolerance in many species, encoding a plasma membrane Na+/H+ antiporter that plays an important role in germination and growth in saline environments. Here we report a preliminary investigation of salt tolerance in quinoa (Chenopodium quinoa Willd.). Quinoa is a halophytic grain crop of the Chenopodiaceae family with impressive nutritional content and an increasing world-wide market. Many quinoa varieties have impressive salt tolerance characteristics and research suggests quinoa may utilize novel mechanisms to confer salt tolerance. At this time there is no published data on the molecular characteristics of those mechanisms. We report the identification and sequencing of the SOS1 gene in quinoa, including a full length cDNA sequence of 3490 bp and a full length genomic clone of 21314 bp. Sequence analysis predicts the quinoa SOS1 homolog spans 23 exons and is comprised of 3474 bp of coding sequence (excluding the stop codon). Introns comprise 17840 bp of the genomic clone and range in size from 77 to 2123 bp. The predicted protein contains 1158 amino acid residues and aligns closely with SOS1 homologs of other species. The quinoa SOS1 homolog contains two putative domains, a Nhap cation-antiporter domain and a cyclic-nucleotide binding domain. Sequence analyses of both cDNA fragments and intron fragments suggest that two SOS1 loci are present in the quinoa genome that are likely orthologous loci derived from the ancestral diploid genomes of the modern allotetraploid quinoa genome. This report represents the first molecular characterization of a putative salt-tolerance gene in C. quinoa.

The construction of the Salt Lake Temple is an in-extricable element of Utah and Mormon history. From the moment of its inception in 1847 until its completion forty-six years later its development coincides closely with the political and economic history of the territory. Its history epitomizes the faith of the Mormon people, attests to the strength of their conviction and serves as a monument to their efforts. It has been a rewarding experience to write the history of the construction of an edifice which has had, and continues to have, such a marked impact on Utah culture.

Personal Digital Assistants (PDAs) are becoming more and more powerful with advances in technology and are expanding their applications in a variety of fields. This work explores the use of PDAs in Virtual Environments (VE). The goal is to support highly interactive bi-directional user interactions in Virtual Environments in more natural and less cumbersome ways. A proxy-based approach is adopted to support a wide-range of handheld devices and have a multi-PDA interaction with the virtual world. The architecture consists of three components in the complete system, a PDA, a desktop that acts as a proxy and Virtual Environment Software Sandbox (VESS), software developed at the Institute for Simulation and Training (IST). The purpose of the architecture is to enable issuing text and voice commands from PDA to virtual entities in VESS through the proxy. The commands are a pre-defined set of simple words such as 'move forward', 'turn right', 'go', and 'stop'. These commands are matched at the proxy and sent to VESS as text in XML format. The response from VESS is received at the proxy and forwarded back to the PDA. Performance measures with respect to response time characteristics of text messages between PDA and proxy over Wi-Fi networks are conducted. The results are discussed with respect to the acceptable delays for human perception in order to have real-time interaction between a PDA and an avatar in virtual world.