Resultados polínicos del Holoceno en la Península Ibérica

El interés que en los últimos años ha adquirido en Europa Occidental el análisis de polen como ayuda al prehistoriador, nos ha llevado a recopilar los datos que tenemos en la Península Ibérica sobre el Holoceno o Postglaciar. Aunque los datos son escasos, y en algunos casos insuficientes, sobre todo para algunas regiones, en general aportan elementos de juicio para que en un futuro no lejano pueda establecerse una secuencia completa, como en el resto de Europa. La evidencia de la sucesión de muchos tipos de asociaciones vegetales en el seno de una unidad geográfica, nos ha conducido a corroborar hipótesis cronoestratigráficas, emitidas anteriormente por los prehistoriadores. Los resultados de la Palinología aplicada a los depósitos arqueológicos ofrecen el interés de dar una imagen parcial, pero significativa, del paisaje vegetal que sirsió de cuadro cotidiano al hombre, y el de evocar a través de este paisaje cierto tipo de clima.Peer reviewe

Recent Trends In American Ethnology

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99690/1/aa.1946.48.2.02a00020.pd

Analytical and Numerical Investigation on Depth and Pipe Configuration for Coaxial Borehole Heat Exchanger, A Preliminary Study

Existing research on the performance of shallow geothermal systems are prone to investigate the ground as a large thermal mass at a constant temperature despite possible temperature increase at depths - otherwise commonly known as the geothermal gradient. Most of the existing analytical models that predict the heat exchange between a borehole heat exchanger with the soil does not allow for the geothermal gradients to be accounted for. The few models that actually does account for the geothermal gradients, on the other hand, does so by enforcing a pre-existing temperature gradient only. We are presenting a bottom up approach in this paper to solve the temperature distribution by accounting for both the convective heat transfer from the working fluid and the conductive heat transfer through both the pipe and the soil. Assuming the heat transfer is entirely axisymmetric, we approach the problem by solving the Navier-stokes equation and energy equation with a finite difference solver that calculates the temporal change of temperature with given diameter, depth of borehole and geothermal gradient. The heat transfer through the pipe and into the ground can therefore be further calculated. We were able to determine a CBHE configuration that allows maximized thermal output by assuming a synthetic heating/cooling load for year-round production of heat

Visualizing the exergy destructed in exergy delivery chain in relation to human thermal comfort with ExFlow

Exergy analysis is an important tool to fully appreciate the usability of energy at different levels and has been widely applied in the building system analysis domain. It has became more useful as low temperature heating and high temperature cooling began to attract more attention both in Europe and the United States. Using low-grade energy to supply for these systems have, in return, led to an increase in awareness of low exergy (LowEx) system designs. The possibility of modeling the last missing link in the system that is to delivery thermal comfort, the human body, have therefore became a topic that increasingly draws the attention of many more researchers. Due to the complexity of these human body exergy models, it is very rare for these models to be linked back to building systems and produce an exergy efficiency for occupants’ thermal comfort. Attempting to fill in the blanks of overall system exergy efficiency on delivery occupant thermal comfort, we have developed a visualization algorithm that could visually assess the exergy efficiency in comfort delivery. Using the ExFlow tool, it is much clearer and easier to determine the relationship of how much primary energy input is eventually converted to the energy that is used to condition for the occupants’ comfort

Exploring potentialities of energy-connected buildings: Performance assessment of an innovative low-exergy design concept for a building heating supply system

Abstract Low exergy building systems generate new possibilities for the design of high performance buildings, especially when the design of a new building is considered as part of a district where the relationship between buildings are optimized to minimize the dispersion of energy in the environment and maximize the recovery of waste energy. We present an innovative design concept and the performance assessment of the heating system of the new Embodied Computation Laboratory at Princeton University. The system is demonstrated to be able to match the heat demand without need for backup systems

Liquid Desiccant-Polymeric Membrane Dehumidification System for Improved Cooling Efficiency in Built Environments

We have recently demonstrated a new type of moisture absorber using a silicone-based liquid desiccant and a nonporous hydrophilic membrane. The setup consists of a core-shell structure where the desiccant flows inside the hydrophilic membrane (core) surrounded with humid air and confined inside a larger diameter tube (shell). In this work, we propose to extend the capabilities of this moisture absorber prototype by addressing two additional characteristics in order to fully validate its capabilities in the built environment. In the first section of this study, we developed a new setup to demonstrate the regeneration process of the liquid desiccant. The regeneration process takes into account the following parameters: (i) air temperature and relative humidity level, (ii) desiccant temperature and water saturation amount, (iii) air/desiccant contact length, (iv) air and liquid desiccant flow rates. In the second part of this paper, we extend our earlier work with this absorber and propose to further improve its performance. We investigate in detail the water absorption kinetics to favor water access to the bulk liquid desiccant surface through efficient mixing inside a confined volume

Doppler-free Yb Spectroscopy with Fluorescence Spot Technique

We demonstrate a simple technique to measure the resonant frequency of the 398.9 nm 1S0 - 1P1 transition for the different Yb isotopes. The technique, that works by observing and aligning fluorescence spots, has enabled us to measure transition frequencies and isotope shifts with an accuracy of 60 MHz. We provide wavelength measurements for the transition that differ from previously published work. Our technique also allows for the determination of Doppler shifted transition frequencies for photoionisation experiments when the atomic beam and laser beam are not perpendicular and furthermore allows us to determine the average velocity of the atoms along the direction of atomic beam

The mystery of the Marajoara: An ecological solution

For more than a century, the beautiful pottery from artificial mounds on the island of Marajó at the mouth of the Amazon has found its way into museums and private collections in Europe and North America, as well as Brazil. Since scientific investigations began in 1948, the discrepancy between the sophistication of the culture and the low agricultural potential of the environment has become increasingly apparent. Although claims that "Marajoara settlement pattern is urban in scale," that "the population could have been up to one million people," and that the ceramic art is "one of the most highly developed in the hemisphere" are extravagant, there is no doubt that the society maintained a relatively high level of complexity during nearly 1000 years in an environment that today supports only a sparse population dedicated mainly to cattle raising. Similar levels of cultural development elsewhere on the planet are sustained either by intensive agriculture or by unusually productive wild resources. Elimination of the former focuses attention on the latter and several new lines of evidence suggest that intensive exploitation of palm starch may be the solution to the mystery of the Marajoara

WATeRVASE: Wind-catching Adaptive Technology for a Roof-integrated Ventilation Aperture System and Evaporative-cooling

The WATeRVASE is a Wind-catching Adaptive Technology for a Roof-integrated Ventilation Aperture System and Evaporative-cooling. Prior research for the adaptive wind catcher technique demonstrates the effective multi-fin design composition for geometry shifting in response to wind directions and speeds (Aviv, Meggers 2018, 186-195; Aviv, Axel, 2017, 1123-1128). Other prior research demonstrates the effectiveness of superporous polyelectrolyte hydrogels for water sorption and diffusion (Smith, 2017, 2481-2488; Ida, 2018). Our team members have also developed a machine-learning platform for testing building technology prototypes for particular environmental conditions and building integration analyses (Smith, Lasch, 2016, 98-105). The new area of research combines the prior work of environmental systems, material science, and electrical and computer engineering for expanding the potential environmental variables that might be addressed simultaneously with the WATeRVASE. Human thermal comfort is one of the most significant challenges in hotarid climate contexts due to energy-intensive building cooling needs, resulting in significant amounts of problematic carbon emissions. Existing experience has shown that passive cooling techniques with natural ventilation and evaporative-cooling provide excellent thermal comfort, together with very low energy consumption (Santamouris and Dionysia 2013, 74-79). The adaptive roof aperture is an advanced passive cooling system that responds to the external airflow thermodynamics by changing its membrane water sorption states to allow either downdraft airflow (saturated top membrane) or nighttime radiation (open top with dry ventilation membrane). In this research, we are developing the adaptive roof aperture functions in the specific hot-arid climate location of Tucson, Arizona. The integration of the hydrogel membrane as an inner surface-lining of the wind-catcher will enable the control of moisture interface with airflow streams via hydropumps with sensors and actuation control, providing evaporative-cooling effects for the daytime downdraft system. Furthermore, the prototype incorporates a lyophilized hydrogel that provides for humidity sorption at the base of the cooling space for water recuperation. The hydrogel membrane may also provide daylighting and thermal conduction mitigation based on saturation states. The project will also explore the potential for rain-water harvesting with the roof-integrated aperture, which is especially necessary for drought-prone hot-arid contexts