Concepts and Benefits of Lunar Core Drilling

Understanding lunar material at depth is critical to nearly every aspect of NASA s Vision and Strategic Plan. As we consider sending human s back to the Moon for brief and extended periods, we will need to utilize lunar materials in construction, for resource extraction, and for radiation shielding and protection. In each case, we will be working with materials at some depth beneath the surface. Understanding the properties of that material is critical, thus the need for Lunar core drilling capability. Of course, the science benefit from returning core samples and operating down-hole autonomous experiments is a key element of Lunar missions as defined by NASA s Exploration Systems Architecture Study. Lunar missions will be targeted to answer specific questions concerning lunar science and re-sources

Repair of composite-to-masonry bond using flexible matrix

The paper presents an experimental investigation on an innovative repair method, in which composite reinforcements, after debonding, are re-bonded to the substrate using a highly deformable polymer. In order to assess the effectiveness of this solution, shear bond tests were carried out on brick and masonry substrates within two Round Robin Test series organized within the RILEM TC 250-CSM: Composites for Sustainable strengthening of Masonry. Five laboratories from Italy, Poland and Portugal were involved. The shear bond performance of the reinforcement systems before and after repair were compared in terms of ultimate loads, load-displacement curves and strain distributions. The results showed that the proposed repair method may provide higher strength and ductility than stiff epoxy resins, making it an effective and cost efficient technique for several perspective structural applications

Modelling of multi-minerals kinetic evolution in hyper-alkaline leachate for a 15-year experiment

Cement has been widely used for low- to intermediate-level radioactive waste management; however, the long-term modelling of multiple mineral transfer between the cement leachate and the host rock of a geological disposal facility remains a challenge due to the strong physical-chemical interactions within the chemically disturbed zone. This paper presents a modelling study for a 15-year experiment simulating the reaction of crystalline basement rock with evolved near-field groundwater (pH = 10.8). A mixed kinetic equilibrium (MKE) modelling approach was employed to study the dolomite-rich fracture-filling assemblage reacting with intermediate cement leachate. The study found that the mineralogical and geochemical transformation of the system was driven by the kinetically controlled dissolution of the primary minerals (dolomite, calcite, quartz, k-feldspar and muscovite). The initial high concentration of calcium ions appeared to be the main driving force initiating the dedolomitization process, which played a significant role in the precipitation of secondary talc, brucite and Mg-aluminosilicate minerals. The modelling study also showed that most of the initially precipitated calcium silicon hydrate phases redissolved and formed more stable calcium silicon aluminium hydrate phases. The findings highlight the importance of a deep and insightful understanding of the geochemical transformations based on the type and characteristics of the host rock, where the system is under out of equilibrium conditions, and the rates of mineral reactions

Nienormatywna metoda wyznaczania izolacyjności akustycznej materiałów płytowych

Non-normative method for determining acoustic insulation of board materials. The paper presents a new method for the measurement of acoustic insulation against airborne sounds in the insulation and construction board materials used in wooden and brick buildings. The primary aim of the study was to simplify the design of a test stand, and thus of individual measurements, while maintaining the confidence level of the results. A series of measurements was performed to evaluate this method’s suitability for determining the acoustic insulation of board materials, and the resulting sound reduction index was analyzed with reference to the tested material and frequency of the generated sound. The study outcomes were found to be consistent with the principles of building acoustics and allowed for drawing preliminary conclusions on the insulating properties of various board materials and sets of materials used for the construction of building partitions.Nienormatywna metoda wyznaczania izolacyjności akustycznej materiałów płytowych. W pracy zaprezentowano nową, opracowaną przez autorów metodę pomiaru izolacyjności akustycznej od dźwięków powietrznych płytowych materiałów konstrukcyjnych i izolacyjnych stosowanych w budownictwie drewnianym i murowanym. Celem pracy było przede wszystkim uproszczenie stanowiska pomiarowego, a tym samym sposobu przeprowadzania pomiarów jednostkowych, przy zachowaniu poziomu ufności otrzymanych wyników. Dla określenia przydatności prezentowanej metody do wyznaczania izolacyjności akustycznej materiałów płytowych dokonano szeregu pomiarów oraz analizy wyznaczonego na ich postawie wskaźnika izolacyjności akustycznej w zależności od rodzaju badanego materiału i częstotliwości generowanego dźwięku. Stwierdzono, iż uzyskane wyniki badań są zgodne z zasadami akustyki budowli i pozwalają na formułowanie wstępnych wniosków odnośnie izolacyjności poszczególnych materiałów płytowych oraz ich zestawów w konstrukcji przegród

Well logging in the world of shale gas plays : interpretative models and specific applications in the shale gas research

The purpose of this article is to review the possibilities of using well logging in the exploration and completion of the shale gas plays. This presentation is addressed to a broad geological community. The article was divided in two parts: the first one, already published in PG, which was focused on the borehole logging tools and methods, and the current one, which deals with the construction of petrophysical models and considers some specific aspects of well-logging application in the shale gas plays. For more inquiring readers, a comprehensive list of literature is presented. The construction of petrophysical models in the thin-bedded shale-sand Miocene gas formation of the Carpathian Foredeep is presented briefly as a possible predecessor of the methodology applicable in the shale gas plays based on domestic experiences. However, the application of well logging in shale gas formations, both at the evaluation and completion steps, differs in the methodology in comparison to conventional and even to thin-bed formations. This specificity is also discussed, where attention is focused on the quantity and quality of organic matter and its relation to gas. Low porosity and a special kind of pore space in organic shales are considered as well

Well logging in the world of shale gas plays : review of the logging methods

The purpose of this article is to review the possibilities of using well logging in the exploration and completion of the shale gas plays. This presentation is addressed to a broad geological community. The article is divided in two parts, the first is focused on the borehole logging tools and methods, while the second describes the construction of petrophysical models and considers some specific aspects of well logging application in the shale gas plays. For the more inquiring readers a comprehensive list of literature is presented. Well logging is the way to acquire an important geological information from the boreholes, parallel to the core data analysis. Laboratory core analysis gives most reliable and comprehensive description of rock parameters, like mineral and chemical composition, kerogen content and its maturity, porosity, the pore space structure, density, permeability etc. However, this kind of analysis is time consuming and expensive. On the other hand, well logs give less accurate and usually not directly measureable values, which must be interpreted to achieve the requested parameters. These measurements are made continuously in natural rock conditions and the results can be obtained very quickly. Proper calibration methods are necessary to link the logging data and the detailed laboratory core analyses. A wide range of well logging tools is described briefly in the paper, and the electrical, nuclear, NMR, and sonic methods are presented in more detail. Special attention is paid to the great technological progress in well logging during the last two decades. This progress allows to cope with the increasing difficulties in the reservoir evaluation. Complicated geometry of the directional borehole, thin beds, shaly-sand lithologies, low porosities, and the specific the pore space distributions are the main challenges in the shale gas plays

Molecular modeling of the effects of 40Ar recoil in illite particles on their K–Ar isotope dating

International audienceThe radioactive decay of 40K to 40Ar is the basis of isotope age determination of micaceous clay minerals formed during diagenesis. The difference in K–Ar ages between fine and coarse grained illite particles has been interpreted using detrital-authigenic components system, its crystallization history or post-crystallization diffusion. Yet another mechanism should also be considered: natural 40Ar recoil. Whether this recoil mechanism can result in a significant enough loss of 40Ar to provide observable decrease of K–Ar age of the finest illite crystallites at diagenetic temperatures – is the primary objective of this study which is based on molecular dynamics (MD) computer simulations.All the simulations were performed for the same kinetic energy (initial velocity) of the 40Ar atom, but for varying recoil angles that cover the entire range of their possible values. The results show that 40Ar recoil can lead to various deformations of the illite structure, often accompanied by the displacement of OH groups or breaking of the Si–O bonds. Depending on the recoil angle, there are four possible final positions of the 40Ar atom with respect to the 2:1 layer at the end of the simulation: it can remain in the interlayer space or end up in the closest tetrahedral, octahedral or the opposite tetrahedral sheet. No simulation angles were found for which the 40Ar atom after recoil passes completely through the 2:1 layer. The energy barrier for 40Ar passing through the hexagonal cavity from the tetrahedral sheet into the interlayer was calculated to be 17 kcal/mol. This reaction is strongly exothermic, therefore there is almost no possibility for 40Ar to remain in the tetrahedral sheet of the 2:1 layer over geological time periods. It will either leave the crystal, if close enough to the edge, or return to the interlayer space. On the other hand, if 40Ar ends up in the octahedral sheet after recoil, a substantially higher energy barrier of 55 kcal/mol prevents it from leaving the TOT layer over geological time.Based on the results of MD simulations, the estimates of the potential effect of 40Ar recoil on the K–Ar dating of illite show that some of 40Ar is lost and the loss is substantially dependent on the crystallite dimensions. The 40Ar loss can vary from 10% for the finest crystallites (two 2:1 layers thickness and <0.02 μm in diameter) to close to zero for the thickest and largest (in the ab plane) ones. Because the decrease of the K–Ar estimated age is approximately proportional to the 40Ar loss, the finer crystallites show lower apparent age than the coarser ones, although the age of crystallization is assumed equal for all the crystallites. From the model it is also clear that the lack of K removal from illite fringes (potentially Ar-free) strongly increases the apparent age differences among crystallites of different size

Molecular modeling of the effect of 40Ar recoil in illite particles on the K-Ar isotope dating of their host rocks

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