Let\u27s Have a Party: Information Literacy Instruction as an Empowerment Strategy

Is it a crazy idea or an innovative pedagogical strategy to turn an information literacy instruction (ILI) session into a party? Joy Kim, Curator of the Korean Heritage Library at the University of Southern California, implements this approach every semester to welcome Korean students to USC campus. Considering the success of her program, perhaps more instruction librarians should take time to organize information literacy welcome parties. International and minority students experience more alienation on campus than average students. Effective ILI often minimizes this sense of alienation felt by these two groups. International students find services available in American libraries are different from what libraries offer in most foreign countries. Minority students are often the first in their family to attend college, and therefore unfamiliar with the university environment and academic libraries. ILI delivered to international and minority students prepares them to claim the academic library as their own territory. While these two groups of users share commonalities, they also differ in considerable ways. It is important for instruction libraries to understand these commonalities and differences, so as to provide most effective service to each group. Let\u27s get together to enable an intellectual exchange between instruction librarians who serve primarily minority populations and/or international students. We hope that by sharing our experiences, participants will identify best strategies for information literacy instruction for international and minority students on their own campuses

Sessile super-droplets as quasi-static wall deformations in direct numerical simulation of turbulent channel flow

Condensation is an important aspect of many flow applications due to the ubiquitous presence of humidity in the air at ambient conditions. For direct numerical simulations of such flows, simulating the gas phase as a mixture characterized by temperature and humidity coupled by the latent heat release and absorption has been shown to yield results consistent with multiphase direct numerical simulations at reduced cost. In the case of surface condensation, the deposition of condensate droplets represents an additional mechanism for flow modification. Extending the single-phase approach by tracking the mean deposition rates and consolidating the condensate mass into static super-droplets reintroduces the effects of surface droplets on the flow while retaining the computational advantages of simulating only the gas phase. Results of simulations of turbulent flow through a cooled, vertical channel with and without such droplets illustrate the additional effects captured compared to the original approach. In the immediate vicinity of a super-droplet, turbulent heat and vapor transport towards the cooled wall is enhanced. Direct impingement and deflection of the flow on the super-droplet cause a qualitative change in the distribution of the condensation rates, increasing on the surface of the super-droplets and decreasing in the surrounding regions. This modification of the near-wall transport leads to increased global cooling and drying efficiency compared to a smooth channel

Isolation and polyphasic characterization of a salt tolerant, plant growth promoting Nostoc sp. from rice paddies in the Ebro Delta

L'estrès de salinitat i alcalinitat es deu a prevalença de les fluctuacions ambientals en els arrossars mediterranis al Delta de l'Ebre; Tanmateix, encara no s'han estudiat en relació amb els cianobacteris terrestres. Entre els diversos cianobacteris, diverses espècies han estat explorades com biofertilitzadors que promouen el creixement de les plantes per millorar el subministrament de nutrients i la tolerància a l'estrès biòtic i abiòtic. En aquesta tesi, diferents cianobacteris van ser aïllats dels arrossars per caracteritzar la seva tolerància a les condicions salines alcalines i per dur a terme una avaluació inicial d'una soca seleccionada com a biofertilitzador per a l'arròs cultivat en condicions salines. En el capítol I, descrivim la caracterització de cianobacteris aïllats de arrossars a l'Institut de Recerca i Tecnologia Agroalimentàries i Marquesa (Delta de l'Ebre, Espanya). Trenta gèneres de destral estaven aïllats de cianobacteris homocistics i hetrocístics. Segons el nostre coneixement, Nostoc paludosum, Nostoc linckia, Nostoc muscorum i Cylindrospermum tropicum es van registrar per primera vegada en aquesta regió. El capítol II tracta sobre la caracterització polifàsica de la diversitat dels trets del gènere Nostoc sota la influència de diferents factors ambientals. Apliquem una combinació de taxonomia moderna i clàssica juntament amb fluctuacions ambientals com la salinitat i l'alcalinitat i utilitzem eines avançades que poden donar llum sobre la complexa diversitat d'aquest gènere. Proporcionem una descripció polifàsica d'un Nostoc sp. (Soca UAB 206) mitjançant anàlisi morfològica (camp clar, fluorescència, contrast de fase, microscòpia TEM confocal i ultraestructural), anàlisi filogenètica (16s rRNA i regió del genoma de la ficocianina) i estudis ecofisiològics (creixement, anàlisi de l'evolució de l'oxigen, eficiència dels fotosistemes I i II i ficobilisomes). Al nostre entendre, aquesta és la primera descripció polifàsica dels cianobacteris en els arrossars del Delta de l'Ebre i la primera aplicació d'aquesta metodologia per a la descripció dels cianobacteris utilitzant diferents tipus de caracterització com a característiques diagnòstiques. XII El capítol III avalua l'efecte combinat de la salinitat (17 a 320 mM NaCl), l'alcalinitat (pHs 7 a 11) i l'edat dels cultius sobre l'aclimatació fisiològica d'un cianobacteri terrestre inexplorat, Nostoc sp. UAB 206. Analitzem el creixement, la fotosíntesi a llarg i curt termini, les activitats del fotosistema II i I, les operacions de ficobilisomes i la producció d'exopolisacàrids. La taxa màxima de creixement i l'activitat fotosintètica fou observada sota la combinació de salinitat de 80 mM i pH 11, en comparació amb el pH 9 i 7. L'augment de la salinitat no va tenir una influència considerable en la taxa de creixement fins a 160 mM a pH 9. L'anàlisi de les corbes de fotosíntesi-irradiància va mostrar que l'activitat màxima de fotosíntesi saturada de llum (Pmax) es va assolir a 17 mM salinitat i pH 11. L'anàlisi espectroscòpica (inclosa la microscòpia confocal) va mostrar que l'augment de la salinitat (80mM) va causar una major eficiència tant del fotosistema II com de l'I en condicions alcalines. L'anàlisi ultraestructural (TEM) va mostrar que les dimensions dels exopolisacàrids van augmentar en la combinació de salinitat de 80 mM i pH 11. En el capítol IV ens centrem en primer lloc en la selecció de varietats d'arròs adequades per a estudis d'estrès i tolerància a la salinitat basats en característiques agronòmiques. Caracteritzem la interacció arròs cianobacteri sota diferents subministraments de nitrogen (50 i 100%) i diferents condicions salines (17, 50 o 100 mM NaCl) en una varietat sensible a la sal (Copsemar). En aquesta interacció, es va observar una influència positiva i beneficiosa dels cianobacteris en la fotosíntesi. Aquest efecte positiu va ser més pronunciat en una baixa oferta de NSalinity and alkalinity stress are the prevalent environmental fluctuations in the Mediterranean paddy fields in the Ebro Delta; however, they have not been studied as yet in relation to terrestrial cyanobacteria. Among the diverse cyanobacteria, several species have been explored as plant growth-promoting biofertilizers to improve nutrient supply and tolerance to biotic and abiotic stress. In this thesis, we isolated different cyanobacteria from paddy fields to characterize their tolerance to saline alkaline conditions and to make an initial evaluation of a selected strain as a biofertilizer for rice grown under saline conditions. In chapter I, we described characterisation of cyanobacteria isolated from paddy fields at the Institute of Agrifood Research and Technology and Marquesa (Delta Ebre, Spain). Thirty axenic genera of homocytous and hetrocytous cyanobacteria were isolated. To our best knowledge, Nostoc paludosum, Nostoc linckia, Nostoc muscorum, and Cylindrospermum tropicum were recorded for the first time in this region. Chapter II addresses polyphasic characterization of the diversity of the traits of the genus Nostoc under the influence of different environmental factors. We applied a combination of modern and classical taxonomy along with environmental fluctuation such as salinity and alkalinity and used advanced tools which may shed light into the complex diversity of this genus. We provide a polyphasic description of a Nostoc sp. (strain UAB 206) using morphological analysis (bright field, fluorescence, phase contrast, confocal and ultrastructural TEM microscopy), phylogenetic analysis (16s rRNA and the phycocyanin genome region) and ecophysiological studies (growth, oxygen evolution analysis, efficiency of photosystems I and II and phycobilisomes). As far as we know this is the first polyphasic description of cyanobacterium in the paddy fields of the Ebro Delta region and the first application of this methodology for description of cyanobacteria using different kind of characterization as diagnostic features. We evaluate the combined effect of salinity (17-320 mM NaCl), alkalinity (pHs7-11) and age of the cultures (from the first to fourth day after VIII inoculation, daily) on the physiological acclimation of an unexplored terrestrial cyanobacterium, Nostoc sp. UAB 206 in chapter III. We look at growth, long and short-term photosynthesis, photosystem II and I activities, phycobilisome operations and exopolysaccharide production. The maximum growth rate and photosynthesis activity observed under combination of 80 mM salinity and pH 11, compared to pH 9 and 7. Increasing salinity did not have any considerable influence on growth rate until 160 mM at pH 9. The analysis of photosynthesis-irradiance curves showed that the maximal light-saturated photosynthesis activity (Pmax) was attained at 17 mM salinity and pH 11. The spectroscopy analysis (including Confocal) showed that increasing salinity (80mM) caused higher efficiency of both photosystem II and I under alkaline conditions. The ultrastructural analysis (Transmission Electron Micrograph) showed that the exopolysaccharide dimensions increased at the combination 80 mM salinity and pH 11. In Chapter IV we first focused on the selection of suitable rice varieties for salinity stress and tolerance studies based on agronomic characteristics. With the selected sensitive cultivar, we then characterized the rice cyanobacterium interaction under different Nitrogen (50& 100 %) and different saline conditions (17, 50 or 100 mM NaCl) in a salt sensitive variet. In this interaction, we observed a positive and beneficial influence of the cyanobacterium on the photosynthesis of the salt-sensitive rice cultivar Copsemar. This positive effect was more pronounced under low N supply

Condensation-induced flow structure modifications in turbulent channel flow investigated in direct numerical simulations

Turbulent flow of a fluid carrying trace amounts of a condensable species through a differentially cooled vertical channel geometry is simulated using single-phase direct numerical simulations. The release of latent heat during condensation is modeled by interdependent temperature and vapor concentration source terms governing the relation between the removal of excess vapor from the system and the associated local increase of fluid temperature. A coupling between condensation and turbulence is implemented via solutal and thermal buoyancy. By comparisons to simulations of an identical system without phase transition modeling, the modifications of the subcooled boundary layer due to the transient and highly localized release of latent heat could be observed. Separate analysis of fluid before and after phase transition events shows a clear increase in post-interaction streak spacing, with the release of latent heat during condensation events opposing the cooling effect of the channel wall and the associated damping of turbulence

Direct numerical simulation of turbulent channel flow with condensation

This thesis presents direct numerical simulations of turbulent humid air flow through a cooled vertical channel at atmospheric conditions. The combination of humidity, temperature and mixed convection is relevant to the ventilation of car interiors, where condensation on critical surfaces such as windows and windshield poses a problem to its immediate or long-term usability. The interaction between buoyancy, convective transport, and phase transitions creates a complex multi-physics problem at the intersection of thermodynamics and fluid dynamics. For the specific range of flow parameters relevant to automotive ventilation, the influence of the liquid phase dynamics is negligible compared to the flow of the gas phase. Leveraging this fact, the single-phase simulation approach uses direct numerical simulations for the solution of the flow fields for the gas phase, including the effect of the phase transition on the velocity, temperature, and vapor concentration of the humid air. It disregards the dynamics within the liquid phase, either neglecting the liquid completely or modeling condensate droplets as static, solid wall deformations. Simulations with and without phase transitions and with and without wall deformations serve to isolate the specific effect of the different influence factors. The combination of direct buoyancy from the cooling and drying of the humid air near the cooled channel wall and the opposing buoyancy contribution from the released latent heat damps the overall influence of the cooled surface on the flow fields compared to cooled channel flow without condensation. In simulations including wall deformations mimicking condensate droplets, the flow across these obstacles create a positive feed-back loop for condensation, increasing the rates at existing droplets

Direct Numerical Simulation of Latent Heat Effects During Condensation in Turbulent Convective Channel Flow

The influence of latent heat released in phase transitions on the flow structures of turbulent convective channel flow of fluid mixtures is investigated using direct numerical simulations. In addition to the usual flow variables, temperature and concentration fields are used to control the phase transition via the local saturation levels. To account fort he intrinsically non-cyclic nature oft he phase transition while ensuring correct turbulence statistics, a coupled simulation approach is employed, where the velocity field of a periodic channel geometry is used to obtain inlet boundary conditions for the primary simulation domai

Direct Numerical Simulation of Convective Channel Flow of Fluid Mixtures

Direct Numerical Simulations (DNS) are used to investigate the extension oft he Boussinesq approximation to include buoyancy effects from concentration gradients. The differences between purely thermal and mixed systems are explored, focusing on mixtures of dry air and water vapor in particular. Such mixtures are highly relevant in ventilation applications, for example in aircraft cabins

DNS of convective channel flow withtemperature and concentration gradients

Mixed convection in a differentially heated channel with an additional concentration gradient is investigated via direct numerical simulation (DNS) using a finite volume method based on fourth order accurate central differences in space and an explicit time integration scheme. The fluid is treated as a homogeneous fluid characterized by its temperature and mixing ratio, and the Boussinesq approximation is employed to calculate the influence of the buoyant forces resulting from density differences due to both quantities in preparation of future investigations of humid air flows in various ventilation applications. The simulations at different values for the modified Grashof number show a distinct effect of the mixing ratio on the flow and temperature profiles for values approximating the conditions found in humid air

Direct Numerical Simulation of Modified Heat Transfer in Turbulent Channel Flow With Condensation

Flows with condensing components occur in a wide variety of critical technical applications. Developing more accurate models for predicting the heat and mass transfer in such flows is predicated upon a solid understanding of the phenomena found in the interaction between phase transition and turbulence. In this work, Direct Numerical Simulation (DNS) is employed to investigate the effect of condensing vapor on turbulent channel flow with a cooled wall, in parallel to ongoing experimental efforts focused on a similar system. Temperature and vapor pressure are added to the governing equations as active scalars, and condensation is triggered based on a localized oversaturation condition. Both buoyancy due to temperature and concentration differences as well as heat injection due to the release of latent heat at the phase boundary are considered. By investigating a simple geometry using highly resolved simulations, the effects of the phase transition can be isolated and observed across all scales, from the microscopic interaction with turbulent flow structures to the changes to boundary layer growth up to the impact on the overall heat transfer. In this investigation, we observe an increase in heat transfer compared to a similar flow without modeled condensation and in line with results from experiments. Additionally, we show that condensation events close to the channel wall are directly affected by the structures of the turbulent flow