Automatic quantitative analysis of microstructure of ductile cast iron using digital image processing

Ductile cast iron is preferred as nodular iron or spheroidal graphite iron. Ductile cast iron contains graphite in form of discrete nodules and matrix of ferrite and perlite. In order to determine the mechanical properties, one needs to determine volume of phases in matrix and nodularity in the microstructure of metal sample. Manual methods available for this, are time consuming and accuracy depends on expertize. The paper proposes a novel method for automatic quantitative analysis of microstructure of Ferritic Pearlitic Ductile Iron which calculates volume of phases and nodularity of that sample. This gives results within a very short time (approximately 5 sec) with 98% accuracy for volume phases of matrices and 90% of accuracy for nodule detection and analysis which are in the range of standard specified for SG 500/7 and validated by metallurgist

Aeronautical engineering: A continuing bibliography with indexes

This bibliography lists 425 reports, articles and other documents introduced into the NASA scientific and technical information system in January 1985

Assessing sandstone reservoir quality: identifying the reality

Quartz cementation is one of the most important cements governing reservoir quality in sandstones. The presence of clay coats plays a crucial role in preserving anomalous high porosity in deeply buried sandstones by inhibiting porosity-occluding macroquartz cementation. More robust and greater grain coat coverage is required for higher temperature reservoirs to preserve significant amounts of porosity. The first and main component of this research entails a series of hydrothermal experiments simulating quartz cementation and grain coat development, particularly authigenic chlorite, at specific temperature steps to mimic the conditions of deeply buried reservoirs and develop predictive models for clay-coat-controlled reservoir quality in such settings. Naturally-occurring sandstone samples from the Lower Jurassic Cook Formation of the Oseberg Field (Norway) were exposed to a silica supersaturated solution for up to 360 hours at temperatures of 0–250 °C. An array of microscopic, analytical and modelling techniques was employed to track the mineralogical alterations, quantify the temperature-dependent volumetric changes of authigenic chlorite, the thickness and coverage of the clay coats, and capture the evolving reservoir quality attributes in the 2D and 3D domain. Results show that grain coating chlorite is formed through a mixture of the solid-state transformation and dissolution-precipitation mechanisms from berthierine transformation, replacement of siderite and neoformation on precursor-free substrate surfaces. Ceasing of porosity loss and permeability maintenance correlate directly to grain coat volume increase at temperatures higher than 175 °C. The second component presents a series of hydrothermal experiments performed on laboratory synthesised biofilm-rich, pure sand samples to test the influence of microbial extracellular polymeric substances (EPS) on early mineral precipitation at temperatures up to 120 °C. An artificial solution was used to synthesise and preserve the microbial communities and promote mineral genesis during each experimental run. Textural evaluation of the samples shows that EPS-coated surfaces serve as templates for the nucleation of early mineral precipitates. Poorly-ordered, morphologically clay-like material developed at points of contact between quartz grains and where EPS structures pre-existed. Future energy and climate change mitigation developments require better characterisation of subsurface reservoirs that can act as energy sources or storage media. This research has important implications for diagenesis studies, providing key insights that can be used to improve predictability of reservoir quality modelling applied in a wide range of geoscience applications

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Geochemical and mineralogical investigations of fine growth structures of ferromanganese nodules from the Clarion and Clipperton Zone, Pacific Ocean

[no abstract

Rare Earth Elements analysis to identify anthropogenic signatures at Valle del Serpis (Spain) Neolithic settlements

Due to their particular geochemical properties and stability Rare Earth Elements (REE) can act as a ‘fingerprint’ for soils, and as a consequence have been employed in a variety of different archaeological scenarios in order to identify past human activities.In this study, for the first time, we apply REE signatures in different Spanish Neolithic settlements, all located in the Valle del Serpis region. More than 100 Neolithic settlements have been identified in this area, and most of these open sites are characterised by dark brown strata that are in contrast with the light brown soils of the valley. These dark brown deposits are usually covered by paleosols and have been interpreted as markers of anthropogenic activities. However, in order to demonstrate whether these strata are anthropogenic or natural features requires a better understand-ing of soil development processes. A total of fifty samples were taken across six different sites, and from each site the sam-pling was carried out at different depths through 3m deep sections. Four sites are clearly associated with archaeological findings (sites BF, LP, PB and AC); another one is from a natural section near the Neolithic site of Mas d’Is (MD) and has been radiocarbon dated to the beginning of the Holocene (7751-7611 cal BC); and the last corresponds to a place of uncertain attribution (BK). Major, minor and trace elements including REE were determined using XRF and ICP- MS, with Principal Components Analysis (PCA) used to statistically analyze these data. Results were then compared with the strata soil properties analysed by XRD and particle size analysis, and cross-referenced with archaeological data to aid interpretation. The results demonstrate that REE analyses provide significant details regarding anthropogenic activities and strata development history, and in this instance confirm and elaborate on the archaeological interpretation that these dark brown deposits are evidence of a region-wide agricultural system in the Neolithic Valle del Serpis

The source of the building stones from the Sagunto Castle archaeological area and its surroundings

A multidisciplinary study was carried out on the building stones of the masonries belonging to the Castle of Sagunto (Valencia, Spain), an important historical and archeological complex, characterized by several construction phases from the Roman Period to the Modern Ages. For the first time, the stones of the Sagunto Castle have been analysed to determine their chemical, mineralogical and petrographic features, the main physical and mechanical properties, and to understand their decay, use and recycling dynamics in the different building during the entire occupational period. Geochemical and mineralogical analyses employing X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray diffraction (XRD) were carried out together with optical and electronic microscope analysis to observe the stone macro- and micro-structures. The collected data were processed by Principal Component Analysis (PCA) to highlight differences among the studied structures. The results show that the stones employed to build Sagunto`s structures during the different historical periods are related to a specific quarried area located nearby Sagunto Castle hill and differences between the studied samples are mostly related to the conservation state of the buildings. Therefore, geochemical analyses confirm the origin of the raw materials, while petrographic and physical analyses have been useful to evaluate the conservation state of the studied Sagunto Castle structures

Friction Force Microscopy of Deep Drawing Made Surfaces

Aim of this paper is to contribute to micro-tribology understanding and friction in micro-scale interpretation in case of metal beverage production, particularly the deep drawing process of cans. In order to bridging the gap between engineering and trial-and-error principles, an experimental AFM-based micro-tribological approach is adopted. For that purpose, the can’s surfaces are imaged with atomic force microscopy (AFM) and the frictional force signal is measured with frictional force microscopy (FFM). In both techniques, the sample surface is scanned with a stylus attached to a cantilever. Vertical motion of the cantilever is recorded in AFM and horizontal motion is recorded in FFM. The presented work evaluates friction over a micro-scale on various samples gathered from cylindrical, bottom and round parts of cans, made of same the material but with different deep drawing process parameters. The main idea is to link the experimental observation with the manufacturing process. Results presented here can advance the knowledge in order to comprehend the tribological phenomena at the contact scales, too small for conventional tribology