Letteratura scientifica selezionata sul tema "Earth Sciences"

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2000.
Includes bibliographical references.
The study of Streaming potentials has applications in the earth sciences, ranging from fluid flow monitoring, to permeability determination, to studying the surface chemistry of rocks and minerals. In this thesis study of frequency-dependent electrokinetics is presented with both theoretical development and experimental verification. The complex (real and imaginary) streaming potential coupling coefficient is explained. This is followed by the first experiments to measure the real and imaginary part of frequency-dependent streaming potential coupling coefficients. As part of this study an experimental apparatus and data acquisition system were constructed to measure the streaming potential coupling coefficients as a function of frequency. The purpose of the experiments was to measure, for the first time, the real and imaginary part of streaming potentials. In addition, the measured frequency range was extended beyond any previous measurements. Frequency-dependent streaming potential experiments were conducted on one glass capillary, two porous glass filters, and one rock. The sample pore diameters ranged from 34 micrometers to 1 millimeter. Without these experiments, the validity of modeling of the frequency dependence of the seismoelectric effect using existing models streaming potential models would be in question. Two frequency- dependent models (Packard and Pride) were compared to the data. Both Pride's and Packard's models have a good fit to the experimental data in the low and intermediate frequency regime where viscous terms dominate in the fluid. In the high frequency regime, where inertial terms start to dominate, the data fits the theory after being corrected for capacitance effects of the experimental setup. Pride's generalized model appears to have the ability to more accurately estimate pore sizes in the porous medium samples. Packard's model has one unknown model parameter whereas Pride's model has four unknown model parameters, two of which can be independently determined experimentally. Pride's additional parameters may allow for a determination of permeability. As part of the study of frequency-dependent electrokinetics, this thesis presents the theory for frequency-dependent electro- osmosis. It is shown that the electro- osmosis frequency-dependent coupling coefficient is constant with increasing frequency until the critical frequency is reached, at which point the coupling coefficient starts to decrease with increasing frequency. The frequency response- electro- osmosiso- osmosis coupling coefficient is dependent on the capillary radius. The smaller the capillary radius the higher the critical frequency. Data is presented for a 0.127 mm capillary. In addition to studying frequency-dependent electrokinetics, this thesis examines the temperature-dependent behavior of streaming potential coupling coefficients. As part of this examination a review is made of the previous literature that discusses the temperature dependence of streaming potentials. The streaming potential coupling coefficient is determined using the permittivity, the conductivity, and the viscosity of the fluid. It has been determined that the temperature-dependent behavior of the permittivity, conductivity, and viscosity are well documented and do not alone account for temperature dependence of streaming potentials. The other quantity used in calculating the streaming potential coupling coefficient is the zeta potential. The temperature dependence of the zeta potential is not well understood at the present time. By examining the theory, it appears that the zeta potential temperature dependence is controlled by the fluid concentration and the adsorption properties of the surface. After examining the theory, streaming potential experiments at elevated temperature and pressure were conducted on Fontainebleau Sandstone, Berea Sandstone, and Westerly Granite. The experiments were conducted in a pressure vessel with temperatures ranging from 23° C to 200° C at pore pressure ranging from 20 bar to 50 bar and confining pressures ranging from 200 bar to 250 bar. The zeta potential was found to increase with increasing temperature, and the coupling coefficient can increase or decrease depending on how the conductivity of the sample varies. This implies that in geothermal regions, streaming potentials can have large magnitudes depending on the conductivity of the geothermal fluid.
by Philip M. Reppert.
Ph.D.

In Hong Kong, Earth Sciences are not a regular subject of the secondary school education. The aim of this project is to build up the students’ curiosity, prompting them to explore, investigate and learning more about Earth Science, ultimately attaining a more detailed understanding of where they live: the Earth. .To this end, a set of curriculum supporting materials, including fieldtrip planning, supplementary materials pack and learning outcomes, has been designed in consult with science curriculum co-ordinators, to facilitate both student learning and teaching of Earth Science-related Hong Kong Diploma of Secondary Education (HKDSE) science subjects. Hong Kong Geopark represents a fantastic resource as a “natural science laboratory”, it is an ideal place for students to observe the real processes which are related to the current curriculums in their studies in secondary schools. Ma Shi Chau, one of the geo-sites in the Geopark, was selected as a destination of the fieldwork route in this project,as it provides an easily accessible opportunity to directly observe part of the Geopark’s superb geological landforms, and discover how their formation relates to fundamental principles of Physics, Chemistry and Biology, learned in the Science curriculum of the HKDSE. The set of the curriculum supporting materials was targeted especially for senior secondary students who are studying for the HKDSE in any Hong Kong traditional schools.
published_or_final_version
Applied Geosciences
Master
Master of Science

Geosites representing different geological environments through time, from Triassic to Pleistocene, have been chosen to promote the study of Earth Sciences in schools in the Marche Region, Italy. The project aims at stimulating students and teachers with a different experimental and interdisciplinary approach with the contextual study of chemistry, biology, geology and ecology. The Geosites introduce a variety of geoscience topics and cover the major themes of Earth science courses in Italian schools. The choice of the sites also meets certain requirements (logistics, appeal, availability of data, appropriateness for the age) to facilitate school field trips or to introduce certain topics at the different school levels. By means of the geosites we intend to facilitate and make appealing the teaching of several Earth Sciences topics such as geomorphology, stratigraphy, sedimentology, mineralogy, paleontology, etc.. with a special focus on the topics relevant for the syllabus of the secondary school level. For each geosite, teaching material (general, specific or interdisciplinary) was produced and made available to the teachers through the University of Camerino website, to support them during the study of the Marche geology and of the geosites. The teaching material consists in power point files (to give general and in-depths information), video-clips, interdisciplinary links, proposals of hands-on activities, students' and teachers' questionnaires. The material produced has been presented to the teachers involved in the experimentation and used for the preparation of the field trips dedicated to the teachers and carried out with some of their classes. The questionnaires administered to teachers and students after the activity allowed to implement the teaching material according to the suggestions and the results of the experimentation. With the material created in this project, teachers without a geological background had the chance to become more confident about geosciences and to deepen their knowledge on geological themes and processes, directly related to their own area. They had also the possibility to apply an experimental and interdisciplinary approach, using data from the field trips to find and propose the students some connections between Earth Sciences and other disciplines. In the geosites students had the possibility to be stimulated to apply their theoretical knowledge thanks to the direct observation in the field, increasing their interest in the topics under study. Since the chosen geosites respond to scientific-educational and practical-logistics requirements, students of different age can use them to study scientific topics at different degree of deepening. The teaching material created for the geosites allow to organize school trips in order to observe directly the themes previously studied at school, to collect data and information in the field and to elaborate them back to school. In this project we focused our attention on two geosite: Frasassi (from 210 to 140 million years ago, Quaternary Era) Monte Conero (from Cretacic to Quaternary Era) The reasons for this choice are: - they cover the entire geological history of the Marche region, from 200 Ma up to present day; - they show very significant events of the Earth history; - they allow to analyze several interdisciplinary aspects. Frasassi Geosite. In order to organize the teaching activities for the Frasassi Geosite three geological footpaths have been identified: Frasassi Walk, Beata Virgin of Frasassi trail and M.Valmontagnana trail. To support learners in their study we produced in-depth studies including geological and interdisciplinary aspect offered by the outcrops, the environments and the panorama of the area. Other two power point files, Umbria-Marche Sequence and Frasassi Caves, complete the study of the area with more general information about the geology of the area and the description of the caves. The practical activities to be carried out at this geosite included also the visit of the museum with hands-on activities on fossils. M. Conero Geosite. For the Conero Geosite seven geological footpath have been identified: Passo del Lupo trail, K-Pg boundary Walk, Fornaci Quarries, Massignano Quarry, M.Conero Short walk, Mezzavalle Beach and Portonovo Ring. Similarly to the Frasassi geosite, we produced teaching material. Another interest point, the Sirolo visitor centre, completes the description of the area. The teaching material created in this project was made available to the teachers in the website (http://d7.unicam.it/teachingearthsciences/) For each geosite there is a topographic map with the indication of the trails chosen to describe the geosite and to cover the geosciences topics. The teaching materials consist in: a) principal power point presentations; b) In-depth studies power point presentation of the topics concerning the Frasassi and Conero Geosites; c) photos and sketches of the trails; d) video-clips of the outcrops and of the panorama; e) students' and teachers' activities hand-outs; f) guide sheets; g) questionnaires with or without answers; h) sitography; i) references; j) on line feedback questionnaires. To introduce secondary school teachers to the geosites we organized preparatory courses, seminars and trips in 2013 and 2014. During the field trips, teachers examined in details the trails and the outcrops in order to organize future activities with their classes. At the end of the teachers' activities, we asked them to answer a feedback questionnaire, in order to have their comments and suggestions about the activities proposed about the geosite. The data obtained were used to improve both the teaching materials and the website. Both teachers and students were administered questionnaires at the end of the field trips to evaluate the appreciation of the activities proposed and the geological themes suggested at the geosites, as well as the interdisciplinary aspects evidenced. The results show a high appreciation for the idea to use the regional geosites for improving the knowledge of Earth sciences, although for this type of activity can be very challenging for the teachers without a geological background. Concerning this, the availability of teaching material with precise description of the point of interest for each geosite has been regarded to be very useful to increase the confidence of the teachers in approaching a field trip or even to introduce the local geology to their classes during formal lessons. Moreover, although the teaching material was intended for secondary schools and experimented on schools of this level, it is possible to modulate the materials to be used for middle schools or even primary schools, providing that a selection of the topics is made by the teacher. In the same way the website can be of wider application since it is available to all the people interested to find information on the relevant points in the geosites of their region. This is particularly important to favour the spreading of knowledge of geological phenomena and their implications for the life of the citizens in areas, like Italy, were the geoenvironmental hazards affect heavily the daily life and can put a risk lives and properties. A better knowledge of geosciences, coming from school, can strongly improve the awareness of the Earth as a living planet and guide the behaviours of the future citizens towards the environment. In the Introduction (Chapter 1) is outlined the alarming decline in young people's interest for key science studied, probably due to "the way science of taught in primary and secondary school". Because of this the purpose of this PhD project is to promote the study of the Earth Sciences in school by stimulating students and teachers with an experimental and interdisciplinary approach offered by the geosites. The aims explain the way we intend to proceed to approach this topic. In the following chapters there is the Methodology (Chapter 2) used to select the geosites, the teaching approach, the organization of the project, the visiting of Museum and display centers, the field trips and the production of teaching tools. Each geosite is presented by illustrating the various trails, outcrops, museum and display center included. There is a description of each field trip and of the tools produced to facilitate the teachers’ work. A brief geological introduction for the two Geosites is reported in chapter 3, with all the geoscience points of interest for the schools and the description of the interdisciplinary topics. Diagrams, chart maps and description of the skills acquired by the students with these activities are presented. The Website (chapter 4) includes all the information and the teaching materials regarding the two geosites including the guide cards and the Earth Sciences study in-depth files. For each geosite there are principal power points, study in depth power points, guide cards, video-clips, pictures and images, student and teacher activity hand-outs and questionnaires. In each power point presentation there are curiosity slides (in blue and yellow), several links to study in depth topics, video-clips, photos, activity hand-outs, worksheets, external website links. At the end of each file there are the sitography and the textbooks and general references. Chapter 5 contains the various phases of the research Experimentation, which included: I. presentation of the geosite trails to teachers; II. use of the website; III. visits to the geosites; IV. use of the learning objects; V. the questionnaires of the principal trails; VI. the on-line questionnaire about Frasassi geosite; In the Results (chapter 6) we show the data obtained from the questionnaire administrated proposed to the participants to the project (teachers, secondary school students, IESO selected students and 1st year University students) about:  secondary school teachers refresher courses;  outdoor experiences;  on-line questionnaire feedback about Frasassi geosite. A Discussion (chapter 7) about the results, thanks to tables, figures and charts, shows the impact that the methodology used in this research had on teachers and students. The results obtained allowed also to evidence weaknesses and strengths of the proposed activities which have been used to increase the effectiveness of the teaching material and of the website content. Chapter 8 summarize the Conclusions reached during this project, evidencing the information obtained by the interaction with the science teachers involved in the experimentation and their comments and suggestions. Interesting factors arising from the experimentation with the students were also sources of inputs for the strategy to carry out field and hands-on activities with students of different ages. The Appendices report examples of a hands-on activity, an in-depth study file, a questionnaire, a list of all the materials produced in this project.

This thesis considers atmospheric superrotation, a state of westerly equatorial winds which must be maintained by up-gradient eddy momentum fluxes. Superrotation has appeared in simulations of warm climates that generate enhanced Madden-Julian Oscillation (MJO)-like variability. This led to hypotheses that the warmer atmospheres of the early Pliocene and Eocene may have been superrotating, and that the phenomenon may be relevant to future climate projections.
Earth and Planetary Sciences

This dissertation examines the negotiations involved in justifying science education, particularly those sciences exploring the earth's 'natural resources', in early nineteenth-century England. Locations ranging from the ancient universities, London societies, to parlour-room lectures, education in the earth sciences was deemed useful because it provided the means to 'improve' the nation, both morally and materially. In the context of educational debates, where the means of reproducing knowledge in a hierarchical society was at issue, the distinctions between scientific theory and the practical applications of such knowledge had to be carefully negotiated. Defining principles upon which a gentlemanly, liberal education was based, against the practical, trained, experimental procedures which were demanded for conducting work in the earth sciences was not easily achieved. It was not easy to reach agreement among those concerned with scientific education as to how much practical detail should be taught. This dissertation examines how establishing rules which governed the acquisition and application of knowledge relied upon defining the values of education. One system of science education was developed within the Cambridge curriculum by Edward Daniel Clarke, professor of mineralogy. Clarke considered Cambridge a place for practically preparing students to enter the governing class. During the Napoleonic wars, concerns over national administration ranged from imperial expansion to effectively exploiting the natural resources that sustained the empire. Standardised methods of analysing the potential value of an imperial frontier relied upon education in the earth sciences.