Deformation mechanisms and their microstructural indicators in the compaction of crushed salt as a geotechnical barrier

Following 30 years of research, it is common sense that crushed salt is the most suitable geotechnical material for encapsulating radioactive waste in a rock salt repository (e.g., Chaikowski et al., 2020). After emplacement, it provides sufficient permeability to allow outflow of unwanted canister-corrosion gases. In the long term, however, when it becomes compacted by converging cavity walls, it safely hinders any fluid flow from and to the waste. Hence, it is essential to know the evolution of (1) the material's key parameters during compaction, such as porosity and permeability, backfill resistance and viscosity; (2) the material's response to environmental controls, such as temperature, humidity, and stress; and (3) the material's long-term rheology. Here we align microstructural deformation indicators with physical processes that underlie compaction (Mills et al., 2018a). We strive to identify and – where feasible – to quantify the dominant deformation mechanisms (Blenkinsop, 2002; Jackson and Hudec, 2017). As a preliminary result, we show that the abundancy of deformation indicators increases with increasing compaction state. In early compaction, we observe more brittle mechanisms, such as grain fracturing (Fig. 1a) and cataclastic flow. At later stages, especially in the presence of moisture, plastic deformation overtakes. Therein, we observe an increased presence of indicators for pressure solution precipitation (grain boundary seams) and dislocation creep (subgrain formation, Fig. 1b), with progressing deformation. In our upcoming work, we aim at linking the observed indicators to environmental controls, such as moisture content, temperature, and strain rate by applying our approach to larger suits of samples compacted under best-known controlled conditions. Final goal is the joint interpretation with findings from in situ-compacted material (Mills et al., 2018b). Do lab tests mimic in situ processes of crushed salt compaction adequately? Can we learn how to do better by means of microstructural investigations?

Comparative Study on Cold Compaction Behavior of TiH2 Powder and HDH-Ti Powder

The compaction mechanism of titanium hydride powder is an important issue because it has a direct impact on density and strength of green compacts and ultimately on the physical and mechanical properties of a final sintered products. In this paper, the characteristics and compaction behavior of titanium hydride and hydrogenation-dehydrogenation titanium powders are comparatively studied and analyzed for better understanding of compaction mechanism of brittle low-strength titanium hydride. The results indicate that the particles of titanium hydride powder are easily crushed under compaction loading at relatively low pressure well below compression strength of bulk titanium hydride, the degree of particle crushed increases with the increase of pressure. The compaction behavior of titanium hydride powder mainly includes the rearrangement and crushing of particles in the early compaction stage, minor plastic deformation, if any, and further rearrangement of particle fragments with filling the pores in the later stage. Such compaction behavior provides relative density of green hydride compacts higher than that for titanium powder of the same size. The relatively coarse titanium hydride powder with wide particle size distribution is easier to fill the pores providing highest green density.

Morphological Evaluation and Grading of Human Embryo Quality from Day - 1 to Day - 3 Embryos for Optimum Conceiving Rate

<p>A grading system of human embryo is very important for embryo selection & predicting blastocyst formation from day - 1, day 2, & day – 3, were sequentially explained. We were designed a methods for grading of embryos from day – 1 (zygote as a pronuclear evaluation, PN), day – 2 (cleavage stage) and day - 3 (evaluation of developmental stage according to cell size and fragmentation) embryo according to cell size and degree of fragmentation and early compaction. In the first grading system pronuclear study and poly-spermy, Second grading system is based on the blastomere / cell number and the observation of fragmentation pattern and selection for embryo transfer, embryos vitrification and pregnancy outcome. Assessment of embryo quality in order to select the embryos that have higher chance to give pregnancy, it is critical goal in IVF cycle or assisted reproductive technologies. ET current trend in human infertility treatment with IVF / ICSI embryo transfer (IVF / ICSI ET) is to increase the chance of higher pregnancy and reduce the multiple pregnancies after multiple embryo transfer according to patient age and endometrium thickness as well as own ART Laboratory protocol. Morphological evaluation & grading of human embryo as a reliable and no-invasive method that provides valuable information & prediction of IVF/ICSI embryos which has developmental potential to reach till early compaction or blastocyst. This research paper describes the current status of morphological embryo evaluation from zygote to eight cell blastomeres or early compaction on late day 3.</p> <p>We found higher embryo development potential and early compaction during in-vitro embryo culture conditions and higher implantation rate in Grade A embryos in comparison transferred of Grade B embryos. Overall embryo development in-vitro and conceiving rate was seen <strong>48.06 %</strong> after embryo transfer of both grades A and Grade B embryos in 233 patients in different age group with different endometrium thickness and multiple embryos transfer in one uterus depend on patient previous history. <strong>935</strong><strong>Embryos was selected from 2702 developing embryos for embryo transfer (ET)</strong> was performed in <strong>233 patients. </strong>After this study we found implantation rate (IR) was <strong>48.06%</strong> based on embryo quality, morphology and grade.</p>

Cotranslational Folding of Proteins on the Ribosome

Many proteins in the cell fold cotranslationally within the restricted space of the polypeptide exit tunnel or at the surface of the ribosome. A growing body of evidence suggests that the ribosome can alter the folding trajectory in many different ways. In this review, we summarize the recent examples of how translation affects folding of single-domain, multiple-domain and oligomeric proteins. The vectorial nature of translation, the spatial constraints of the exit tunnel, and the electrostatic properties of the ribosome-nascent peptide complex define the onset of early folding events. The ribosome can facilitate protein compaction, induce the formation of intermediates that are not observed in solution, or delay the onset of folding. Examples of single-domain proteins suggest that early compaction events can define the folding pathway for some types of domain structures. Folding of multi-domain proteins proceeds in a domain-wise fashion, with each domain having its role in stabilizing or destabilizing neighboring domains. Finally, the assembly of protein complexes can also begin cotranslationally. In all these cases, the ribosome helps the nascent protein to attain a native fold and avoid the kinetic traps of misfolding.

Salt anomalies in potash beds of the Esterhazy Member, Devonian Prairie Evaporite Formation, Saskatchewan, Canada

The Esterhazy Member of the western Canada Prairie Evaporite has been mined underground for sylvite (KCl) since the early 1960s. Although the geology of the Esterhazy Member ore body is largely considered a regional flat lying continuous series of thin potash hosting beds, there are numerous occurrences where the ore has been either replaced or removed leaving behind uneconomical halite-rich sections. An explanation of the underlying controls on the formation of these salt anomalies has been somewhat elusive although the overwhelming assumption remains that these features developed in lows on a salina. This paper proposes that salt anomalies formed because of two processes, early compaction of carbonate shoals of the Winnipegosis Formation and tectonics that resulted in multiple stages of block movement during the deposition of the upper Prairie Evaporite. Since these two processes can result in a significantly different size to a salt anomaly, encountering one or the other type can have a significant effect on the economics of the ore body. This paper looks at some of the geological methods that might provide geologists with means to predicting salt anomalies.

Diagenesis of Xing’anling Oil Reservoir in Sudeerte Area

In order to explore the types of diagenesis in Sudeerte area, through core and thin slice identification, it is clear that the Xing’anling oil layer is mainly affected by compaction, cementation, andrecrystallization. The compaction is mainly early compaction, late pressure dissolution is not obvious; cementation presents two forms of crystalline quartz and amorphous opal; recrystallization is manifested as the conversion process of opal t-ochalcedony quartz.

The role of salt tectonics and overburden in the generation of overpressure in the Dutch North Sea area

In this paper we study the effects of timing of salt movement and mechanical compaction on the generation of overpressures in Mesozoic rocks. To that end we apply 2D basin modelling on two N-S trending cross sections in the Dutch Central Graben and Terschelling Basin, respectively. Several overpressuring scenarios were calculated by modifying the mechanical compaction of the sealing layer, the rate of sedimentation, and the timing of salt movement. Pressure and porosity measurements from several wells along the cross sections were used as calibration data. The results show that rapid sedimentation and early compaction of Pliocene to Quaternary mudstones explain most of the overpressures in the Cretaceous and Jurassic rocks. The modifications of the mechanical compaction of the Upper Cretaceous Chalk Group performed in this study could not explain the overpressure anomalies in the southern part of the Dutch Central Graben. Processes such as chemical compaction are probably more important in this respect. Overpressures in the Triassic are mainly controlled by the timing of salt movement and the closure of lateral seals. This study has lead to a better understanding of the processes that generate overpressures and those that are involved in their lateral distribution. The integration of modelling scenarios and information on the timing of seal formation enables to define new play concepts and is important for the assessment of possible drilling hazards as well.

Diagenesis and Controlling Factors of Kalashayi Clastic Reservoir in South of Tahe Oilfield

The Kalashayi sandstone reservoir deposited in tidal-flat facies. Main diagenesis include compaction, cementation and dissolution, which compaction belongs to middle-weak, point to linear contact between grains and pore-space cementation by carbonate rocks; dissolution features that feldspar grains and carbonate cementation’s dissolution. The reservoir is mesopore and medium permeability reservoir in a current depth of 4800-5300m. The reason cause this mesopore and medium permeability reservoir are considered as the following factors. The physical properties of reservoirs are mainly controlled by sedimentary microfacies and diagenesis. The strong tidal channels and tidal creaks current leads to the composition of rock mineral pure, quartz content is high, the grains coarser, good sorting and low matrix. The early compaction was so little that some pores were conserved in carbonate cementation, and in the later diagenetic process, carbonate cementation were corroded to secondary pores.