Lineamenti teorici di nuovi metodi di carotaggio fisico:Matranslog & Phaselog

Riassunto L'A., dopo ricordato un suo studio pubblicato un anno addietro circa la possibilità di realizzazione di unMatranslog (misure transitorie e. m.-elettromagnetiche nei fori sonda), sviluppa la teoria considerando un emittore e. m. di dimensioni finite. Sia il dipolomatrans che il bipolomatrans presentano analoghi comportamenti temporali. L'A. mostra le proprietà delle caratteristiche impulsive delMatranslog per suoli uniformi. Accenna quindi alle equivalenti caratteristiche di frequenza coll'ideazione d'un adeguatoPhaselog.

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Summary After recollecting a study published a year ago by himself about the possibility of constructing aMatranslog (electromagnetic measures of transients in boreholes), Author develops the relative theory, considering an e. m. generator of limited dimensions. Bothmatrans dipole andmatrans bipole offer similar time behaviour. Writer shows the properties of the pulse characteristics of theMatranslog for homogeneous grounds. He hints to the equivalent frequency characteristics deducted by means of an adequatePhaselog.

     

Proprietà fondamentali dell'elettrogeosmosi stazionaria,conseguenze applicative

Riassunto Dalle correlazioni da noi evidenziate tra portate elettrogeosmotiche e pressioni geoidrostatiche si passa alle norme della regolazione dell'elettroprocesso. Correlazioniamo inoltre le portate idriche con le correnti e tensioni applicate nonchè con le correnti e tensioni critiche o di soglia. Si analizza a fondo il rendimento elettrogeosmotico, calcolando il massimo, il minimo, quelli parziali o polari. Si deduce un principio di mescolamento elettrodico e altre prassi d'interesse applicativo.

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Summary After having brought into evidence the relationships between electrogeo-osmotic flow and geo-hydrostatic pressure, the A. shows the regulation rules of electro-process. Besides, the A. relates hydraulic flows to currents and tensions, as well as to critical, or threshold currents and tensions. The A. analyses to the narrow electro-osmotic efficiency, by calculating the highest and lowest efficiences, and the partial or polar ones. It can be derived a multi-electrode pattern, and several other application processes.

     

Elettrogeosmosi a limite mobile

Riassunto Viene studiato l'andamento EGO quando all'anodo si crea uno strato isolante progrediente nel tempo:EGO a limite mobile. Dalla teoria discende una prassi operativa EGO atta a contenere lo strato tampone (elettricamente resistivo).

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Summary The electro-osmotic phenomenon (EGO) is studied with regard to an insulating layer which builds up at the anod (mobile-limit EGO). An efficient operative method may be to lower the input voltage by the same ratio as the ohmic resistance increases. Practically it may be sufficient to lower the input voltage by a fixed percentage now and then, i. e.; at the time the ohmic resistance increases, or some time before. The aim is to prevent the formation of «stopper resistances» in order bo get a suitable electric current flow i. e., keep low the ohmic resistance lowering continually the voltage.

     

Qualitative analysis of cosmological models in Brans-Dicke theory

Isotropic and homogeneous cosmological models with a perfect fluid cource in Brans-Dicke theory are investigated from the point of view of dynamical system theory.Work partially supported by CNPq (Brazil).     

Settlement Analysis of Açu Dam,Brazil

Geotechnical and Geological Engineering - The Armando Ribeiro Gonçalves Dam, popularly known as The Açu Dam, is an important geotechnical construction in Rio Grande do Norte state,...     

Effects of mining wastes on a seagrass ecosystem: metal accumulation and bioavailability, seagrass dynamics and associated community structure

Two different Cymodocea nodosa (Ucria) Ascherson beds growing in mining-contaminated sediments were compared with two reference beds in the Mar Menor coastal lagoon. The accumulation of Zn, Pb and Cd in different fractions of the plant, the sediment parameters that regulate the availability of metals, the seabed structure and dynamics of each seagrass bed and its associated macroinvertebrate community were studied. C. nodosa accumulates metals from the sediments and reflects their bioavailability for this seagrass. At each station, the metal content of the rhizomes was lower than that of leaves and roots. The concentration of acid-volatile sulfides does not seem to influence the availability of metals to the seagrass, possibly due to oxygen transport to underground tissues. The highest metal concentration in all the contaminated stations was found in the leaf-biofilm, due to the formation of complexes between metals and the extracellular polymeric substances that form the biofilm. All the seagrass beds were seen to be undergoing expansion, those growing in contaminated sediments accumulating great quantities of metals and showing highest photosynthetic leaf surface area and highest leaf biomass. However, these structural parameters were not seen to be responsible for the differences in the faunal composition observed between contaminated and reference beds. Moreover, the multivariate analysis identified the metal content of leaves, biofilm and sediments as important variables that may be responsible for these differences in faunal composition. In this study we have demonstrated that both the seagrass C. nodosa and the biofilm on the plant leaves may be used as environmental tools in the Mar Menor lagoon. The former is an useful indicator of sediment contamination, whereas the latter seems to be a good sentinel of water quality.     

Elettrobisol simultaneo a cella tripolare

Riassunto L'A. ha qui escogitato una equivalenza bisol-monosol, realizzabile sul terreno, per instaurare «elettrodiaframmi», «elettroparatie» a qualsiasi distanza dagli iniettori di legante. Ne studia gli aspetti fenomenologici principali, corredandoli di grafici utili all'impiego del metodo.

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Summary This paper deals with the devising of an equivalence bisol-monosol, which can be performed into soil, in order to carry into effect «electro-diaphragm» and «electro-pilings» at any distance from binding-solution electro-injectors. Principal aspects of phenomena are studied, and graphs useful for applyng the method are given.

     

The Itaja�� foreland basin: a tectono-sedimentary record of the Ediacaran period, Southern Brazil

The Itajaí Basin located in the southern border of the Luís Alves Microplate is considered as a peripheral foreland basin related to the Dom Feliciano Belt. It presents an excellent record of the Ediacaran period, and its upper parts display the best Brazilian example of Precambrian turbiditic deposits. The basal succession of Itajaí Group is represented by sandstones and conglomerates (Baú Formation) deposited in alluvial and deltaic-fan systems. The marine upper sequences correspond to the Ribeir?o Carvalho (channelized and non-channelized proximal silty-argillaceous rhythmic turbidites), Ribeir?o Neisse (arkosic sandstones and siltites), and Ribeir?o do Bode (distal silty turbidites) formations. The Apiúna Formation felsic volcanic rocks crosscut the sedimentary succession. The Cambrian Subida leucosyenogranite represents the last felsic magmatic activity to affect the Itajaí Basin. The Brusque Group and the Florianópolis Batholith are proposed as source areas for the sediments of the upper sequence. For the lower continental units the source areas are the Santa Catarina, S?o Miguel and Camboriú complexes. The lack of any oceanic crust in the Itajaí Basin suggests that the marine units were deposited in a restricted, internal sea. The sedimentation started around 600?Ma and ended before 560?Ma as indicated by the emplacement of rhyolitic domes. The Itajaí Basin is temporally and tectonically correlated with the Camaqu? Basin in Rio Grande do Sul and the Arroyo del Soldado/Piriápolis Basin in Uruguay. It also has several tectono-sedimentary characteristics in common with the African-equivalent Nama Basin.     

Unusual Carbonatite Lavas from Active Volcano, Oldoinyo Lengai

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Unusual Carbonatite Lavas from Active Volcano, Oldoinyo Lengai