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The relationship between microbial activity and the supergene modification of ore systems has been a major subject of debate. Here, we present isotopic evidence of microbial-driven secondary copper mineralization in the active cementation zone of the Las Cruces deposit, a volcanogenic massive sulfide deposit located in Iberian Pyrite Belt, Spain. Copper isotopic data show that the lower isotopic ratios (δ65Cu ≈ −9.2 ± 0.11 ‰, the lowest value measured worldwide in a supergene environment) are found in the upper part of the cementation zone, the same zone where the maximum copper grades are found and where there is direct evidence of extremophilic microbial activity. There is a tendency towards higher values downwards through the cementation zone (−9.2 ± 0.11 ‰ to + 1.67 ± 0.11 ‰ δ65Cu) and upwards into the former Cu-depleted gossan that originally capped the cementation zone (−7.79 ± 0.11 ‰ to −1.32 ± 0.11 ‰ δ65Cu). As microbes preferentially sequester the lighter isotope when incorporating intracellular Cu, this distribution indicates that microbes played a major role in the formation of the high-grade zones. Water arrives to the deposit enriched in isotopically heavy copper, likely because it has leached other ore bodies upstream. δ65Cu values of water currently flowing into the system are remarkably more positive than those in the ore, indicating that microbial activity is a major cause of copper isotope fractionation. At least half of the copper transported by the incoming waters remains within the ore body. Our best interpretation is that the large and high-grade cementation zone at Las Cruces is of biogenic origin, and that the primary mineralization acted as a trap for copper transported by groundwater, leading to the formation of an exotic mineralization distal to sub-eroded massive sulfides located upstream. [ABSTRACT FROM AUTHOR]

The article focuses on comparing the clinical and radiological outcomes of a newly introduced modified manual cementation technique with a second-generation technique in primary cemented hip arthroplasty. Topics include operation duration, intraoperative complications, and postoperative outcomes such as Visual Analog Scale (VAS) score and Harris hip score.

Carbonate reservoir rocks are usually heterogeneous, so it is not an easy task to establish a relation between porosity and permeability in these types of reservoir rocks. First, Kozney and Kozney-carmen formulas were used to establish these relations. Later, the flow zone indicator (FZI) method was introduced, which was widely used to find such a relation since it shows better results than the two former methods. In this work, the classical FZI method and a modified form of the FZI method were utilized to identify the hydraulic flow units and rock quality index to predict permeability. In the modified FZI method, the cementation factor (m) was introduced in calculating the value of FZI. The data collected from core analysis of the cored intervals in the Tanuma and Khasib formations were used as a database for this work. The classical and the modified FZI methods were applied using the database to predict core permeability. The value of the cementation factor was tuned to get a better match between the predicted permeability resulting from applying the modified method and the measured permeability values. Results show that the correlation coefficients resulting from applying the modified FZI method are closer to unity compared with that resulting from the classical FZI method. Cementation factor (m) of m = 3 for Tanuma formation and m = 3 for Khasib formation are the best values used with the modified FZI method. The modified FZI method shows a regression factor of 0.9986 for Tanuma and 0.9942 for Khasib formation. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of aging on the morphology of the interface between monolithic implant crowns and standardized titanium base abutments.Materials and Methods: Four groups of hybrid abutment crowns differing in restorative material (lithium disilicate [LD] or polymer-infiltrated ceramic network [PICN]) and in fabrication procedure of the interfacial zone for luting to a titanium abutment (milled during CAD/ CAM procedure [M] or prefabricated [P]) were formed: LDS-M, LDS-P, PICN-M, and PICN-P (n = 10 each). The morphology of the crown-abutment interface was examined before and after artificial aging using scanning electron microscopy. The total gap length per specimen was measured at both time points, and intergroup (Kruskal-Wallis [KW]) plus pairwise (Wilcoxon Mann-Whitney [WMW]) comparisons were performed (α = .05).Results: Before aging, statistically significant differences in gap length were identified among groups (KW: P = .0369) for PICN-P > LDS-P (WMW: P = .0496) and LDS-M > LDS-P (WMW: P = .0060). The effect of aging among the groups, expressed as an increment of total gap length, was 50% in LDS-M, 30% in LDS-P, 20% in PICN-M, and 30% in PICN-P. After aging, the statistically significant differences in gap length identified among groups (KW: P = .0048) were for PICN-P > LDS-P (WMW: P = .0134); LDS-M > PICN-M (WMW: P = .0204); PICN-P > PICN-M (WMW: P = .0486); and LDS-M > LDS-P (P = .0022). However, comparison of the difference in gap length from before to after aging among the groups was not statistically significant (KW: P = .3549).Conclusion: The cementation interfaces of CAD/CAM crowns on standardized titanium base abutments demonstrated a high percentage of gaps before and after thermomechanical loading. The composition of the restorative material and the nature of the interface influenced the interfacial gap dimension. [ABSTRACT FROM AUTHOR]

To clarify the development rules and main origins of deep tight conglomerate reservoirs in the Mahu area of Junggar Basin, various materials and data from deep wells were systematically researched to determine the reservoir's basic characteristics and effective origins. The results indicate that the reservoir mainly comprises a fine and medium-fine conglomerate, which belongs to the fan delta distributary channel conglomerate. Additionally, it is a typical deep tight conglomerate reservoir with low to ultra-low porosity and permeability, and the gravel primarily consists of volcanic rock composed of tuff and intermediate acid volcanic lava. The cement is mainly composed of laumontite and calcite, and the reservoir has undergone three types of diagenesis: compaction, cementation, and dissolution. The first two types have dual effects of destruction and construction, while the result of dissolution is the widespread development of secondary pore enrichment zones composed of intergranular solution pores formed by the dissolution of zeolite, carbonate cement, and argillaceous matrix, as well as intragranular solution pores formed by the dissolution of feldspar and dark minerals. Unlike the middle and shallow layers, the reservoir space mainly composed of secondary pores and fractures. The effective reservoir is mainly caused by rock composition, dissolution, fracture system, and abnormal high pressure. The rock composition provides a sufficient material basis and is the internal cause, while the dissolution, fracture system, and abnormal high pressure are the external causes. The dissolution forms a secondary pore enrichment zone, the fracture system improves the seepage capacity of the reservoir, and abnormal high pressure can effectively maintain and increase the pores. Four factors control the formation and distribution of relatively highquality deep tight conglomerate reservoirs. [ABSTRACT FROM AUTHOR]

Dust is an environmental and health hazard. In this study, a new technology for dust suppressant is introduced using soybean urease with an optimal cementing solution. Calcium carbonate is produced by soybean urease and cementing solution, which bonds the soil particles towards a dust suppressant. A laboratory wind tunnel test is carried out to examine its effectiveness and discover possible optimization solutions. Several factors, including soybean meal concentration, cementing solution concentration, and volume of solution per unit area, are examined to quantify their influences on soil transport mass, evaporation ratio, evaporation rate, surface strength, water retention ratio, and infiltration rate of soil treated by different dust suppressants. Field tests are conducted to explore the performance of this method in the natural environment. The results show that compared with other dust suppressants, the optimized soybean urease has the smallest evaporation rate, a moderate infiltration rate, the largest water retention ratio and surface strength. The indexes of soybean urease for dust suppressant are found to be better than traditional materials. In the natural environment, soybean urease has a stronger anti-disturbance ability. This study concludes that soybean urease dust suppressant has great application potential as a cheap and green method. [ABSTRACT FROM AUTHOR]

This article presents the historical development of the different generations of zirconia and their range of indications, from veneered to monolithic zirconia restorations. While Part I concentrated on detailed information about the development of zirconia for dental use and the mechanical and optical properties, Part II deals with the resulting guidelines for working with the relevant generations by summarizing the correct cementation procedure. Furthermore, this part also focuses on translucency measurements for better characterization and understanding of the different materials. The results obtained from measuring light transmission and contrast ratio are compared and discussed in detail, with the aid of clinical photographs. Finally, the reader is given practice-relevant recommendations for different areas of clinical use of the zirconia generations along with advice on how to process them appropriately. [ABSTRACT FROM AUTHOR]

Developments in machine manufacturing technology necessitate the quality performance of the finished surfaces to be in parallel. The burnishing method is carried out to surfaces in different geometries, and its effect on the normal machined surface quality has been demonstrated by various scientific studies. However, by subjecting the surface to more than one burnishing process, it is limited to obtain sufficient data on the surface properties of the material. In this study, AISI 8620 cementation steel, which is one of the materials commonly used in machine manufacturing, was preferred especially since a toughness in the core, a hard surface resistant to abrasion on the peripheral surface, and a ductile structure in impact work at required. The material was prepared 20 mm diameter with the turning method under the same machining parameters. On 4 of the 5 leveled surfaces prepared; In the examinations and comparisons made after the burnishing process applied from 1 burnishing number to 4 burnishing numbers, the best results were obtained in terms of surface roughness in 2 burnishing operations and surface hardness in 3 burnishing operations. The worst values were obtained in 1 burnishing operation for surface roughness and 4 burnishing operations for surface hardness. [ABSTRACT FROM AUTHOR]

Aim: This in-vitro study aimed to evaluate the translucency and color stability of bleached veneer shades with different resin cement. Material and Methods: Forty-two IPS E-max CAD discs with bleached shades BL1 and BL3 milled by CAD/CAM, each disc was 0.5 mm in thickness, 10 mm in diameter. Each sample had been formed by cementation of IPS E-max CAD discover a PMMA disc 1 mm in thickness 10 mm in diameter with shade A2 by two different shades of resin cement from Variolink NLC shades clear and +2. This cementation done by using standardized mold 1.6 mm in thickness, with cement layer 0.1 mm. Translucency and color of each sample had been measured by Spectrophotometer. Transparent parameter and color difference ΔE had been calculated and analyzed by one-way analysis of variance then multiple comparison Tukey's test (α = 0.05). Results: Using clear shade cement under both shade of IPS E-max showed lower than ΔE with cement shade +2. P value was highly significant in all samples (Δ > 0.000), while in BL3 disc before cementation and after cementation with clear cement showed nonsignificant result (Δ > 0.227). Transparent parameter was higher before cementation and the lowest value obtained with shade + 2 cement which is opaquer (10.59) with BL3 and (11.69) with BL1. Conclusion: The final color and translucency of bleached veneers is influenced by the shade of resin cement. [ABSTRACT FROM AUTHOR]

Gold parting enabled the production of very pure gold for various purposes from the sixth century BC onwards, but analytical proof of this pyrotechnical process is difficult. We describe a new analytical approach for the identification of purified gold combining silver and copper isotopic with trace element analyses. Parting experiments were performed with gold-silver-copper alloys using the classical salt cementation process to investigate potential silver and copper isotope fractionation and changes in trace element concentrations. In addition, we provide the first comprehensive dataset of silver isotope ratios of archaeological gold objects from the Mediterranean and Central Europe to test whether or not gold refining can be identified on the basis of isotope systematics. The results show that very heavy silver and copper isotopic compositions are clear evidence for parted gold, but that the application of copper isotopes might be limited. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to compare the pull-out bond strength of prefabricated titanium posts cemented with novel fast-setting calcium silicate, zinc phosphate, or glass ionomer cements. Methods: Sixty extracted human maxillary incisors were selected and received root canal treatment. Post space was prepared for titanium ParaPost XP size 5 (diameter=1.25 mm). The posts were cemented using novel calcium silicate cement, zinc phosphate cement, or glass ionomer cement (n=20). Specimens were stored in phosphate-buffered saline for 4 weeks. Subsequently, the posts were subjected to axial tensile force until bond failure. Data were analyzed by one-way ANOVA followed by multiple comparisons. Results: The posts cemented with novel calcium silicate cement (10.5±3.8 MPa) demonstrated significantly higher bond strength than zinc phosphate (8.0±2.6 MPa) and glass ionomer cements (8.0±2.7 MPa) (P<0.05). Conclusion: Within the limitation of the study, the pull-out bond strength of titanium post cemented with novel calcium silicate cement in endodontically treated teeth was superior to zinc phosphate and glass ionomer cements. [ABSTRACT FROM AUTHOR]

In order to solve the problems of large deformation and difficult control of the soft rock roadway floor under the influence of high stress and mining stress superposition in Zhaogu mining area, this paper analyzes the stress environment and failure mechanism of the surrounding rock by means of on-site investigation, numerical simulation and on-site industrial test. It is considered that the floor heave of the soft rock roadway is the result of the joint action of the surrounding rock fracture development, poor lithology, cementation, low strength of the original support and high ground stress. The distribution characteristics of stress, displacement and plastic zone of surrounding rock in soft rock roadway under different stress and support mode are analyzed by numerical simulation. Based on the above analysis, the combined control technology of "prestressed grouting anchor cable + grouting anchor bolt + grouting behind the wall + floor reconstruction" is proposed to effectively control the occurrence of roadway floor. The data of monitoring verifies that the grouting bolt changes the structure of broken coal and rock mass on the floor and restrains the occurrence of floor heave. [ABSTRACT FROM AUTHOR]

Oysters are unusual among bivalves in that they possess chambers, often filled with soft, chalky calcite, that are irregularly scattered throughout the shell. Because the function of these so-called chalky deposits is still unclear, evaluating the growth and distribution of chalk is important for elucidating the ecological function of this unique shell trait. Specimens of the Pacific oyster Magallana gigas, an oyster well known for chalk expression, were grown in Bodega Harbor, Bodega Bay, CA. At the end of an 11 month growing period, specimens were culled and selected animals were submitted for x-ray computed-tomography imaging. Three-dimensional reconstructions of oyster shells were used to assess the overall distribution of chalk, and also to better understand the relationship between chalk and other structures within the shell. Results indicate that chalky deposits underly sculptural features on the shell exterior, such as external ridges and changes in growth direction, and also that there is a relationship between chalk formation and oyster processes of cementation. Overall, chalk is useful for a cementing lifestyle because it enables morphological plasticity needed to conform to irregular substrates, but also acts as a cheap building material to facilitate rapid growth. [ABSTRACT FROM AUTHOR]

According to characteristics of carbonate fracture-cave reservoir and applying imaging logging data with high resolution and abundant information, combining calculated cementation exponent of conventional logging data, the thesis calculates qualitative recognition fluid property of apparent formation water resistivity spectrum. The thesis crosses mean and variance of apparent formation water resistivity spectrum of different wells in different areas, sets standard to fluid recognition and recognizes fluid property quantitatively. [ABSTRACT FROM AUTHOR]

Purpose: Excess residual cement around the implant margin has been shown to be detrimental to the peri-implant tissue. This in vitro study examines the retentive strengths of two different cementing techniques and two different luting agents on a machined titanium abutment and solid screw implants. The amount of reduction of excess cement weight between the two cementation techniques was assessed. Materials and Methods: Forty gold castings were fabricated for 4.1 mm in diameter and 10 mm in length solid-screw dental implants paired with 5.5-mm machined titanium abutments. Twenty implants received a provisional cement, and 20 implants received a definitive cement. Each group was further divided into two groups. In the control group, cement was applied and the castings seated over the implant-abutment assembly. The excess cement was then removed. In the study group, a "practice abutment" was used to express excess cement prior to cementation. The weight of the implant-casting assembly was measured and the residual weight of cement was calculated. The samples were then stored for 24 hours at 100% humidity prior to tensile strength testing. Results: Statistical analysis revealed significant differences in tensile strength across the groups. Further Tukey tests showed no significant difference in tensile strength between the practice abutment technique and the conventional technique for both definitive and provisional cements. There was a significant reduction in residual cement weight, irrespective of the type of cement, when the practice abutment was used prior to cementation. Conclusions: Cementation of implant restorations on a machined abutment using the practice abutment technique and definitive cement may provide similar uniaxial retention force and significantly reduced residual cement weight compared to the conventional technique of cement removal. [ABSTRACT FROM AUTHOR]

Purpose: This investigation compared initial and fatigue strengths of particle-abraded ceramics to those of as-polished alumina and zirconia ceramics in crown-like layer structures. Materials and Methods: Alumina or zirconia plates bonded to polycarbonate substrates were subjected to single-cycle and multi-cycle contact (fatigue) loading. Cementation surfaces of the ceramic were damaged by controlled particle abrasion, indentation with a sharp diamond at low load, or a blunt indenter at high load. The stresses needed to initiate radial fractures were evaluated. Results: The strengths of specimens were lowered by fatigue loading. After the equivalent of 1 year of occlusal contacts, the strengths of undamaged specimens degraded to approximately half of their single-cycle values. In particle-abraded specimens, an additional 20% to 30% drop in strength occurred after several hundred load cycles. Particle abrasion damage was approximately equivalent to damage from sharp indentation at low load or blunt indentation at high load. Conclusion: Damage from particle abrasion, not necessarily immediately apparent, compromised the fatigue strength of zirconia and alumina ceramics in crown-like structures. In fatigue, small flaws introduced by particle abrasion can outweigh any countervailing strengthening effect from compression associated with surface damage or, in the case of zirconia, with phase transformation. [ABSTRACT FROM AUTHOR]

The adhesive luting technique for ceramic inlays requires a sequence of multiple steps that are cumbersome and time consuming. Furthermore, modifications of dentin bonding procedures may negatively influence the margin quality of ceramic inlays with cervical dentin finishing lines. Purpose: The objective of this study was to test the effect of a new, simplified procedure for dentin bonding on the margin quality of ceramic inlays. Materials and Methods: Thirty-two MOD inlay cavities with cervical finishing lines in dentin were prepared into premolars. They were randomly divided into four groups (n = 8): In the balanced design, one parameter was the inlay material (Empress/Cerec) and the other the polymerization of the dentin bonding agent, before insertion of the inlay (P+) and after insertion of the inlay (P-). All inlays were inserted with Variolink II in combination with an enamel and dentin conditioning universal bonding agent (Etch & Prime 3.0). Two parameters were used to determine the inlay quality: (1) the fit, measured by the difference of the insertion depth into the cavity between try-in and cementation, and (2) a quantitative margin analysis in the SEM at a magnification of 200x, performed for the cervical segment before and after thermocycling, using epoxy replicas. Results: In all four groups the inlays were >5 μm deeper in the cavities than at the try-in session. This is explained by the substance loss from the etching. The measured difference for Cerec inlays inserted in cavities, where the bonding agent was not polymerized prior to insertion, was significantly larger. Margin analysis of the cervical segment revealed no statistical differences (P < 0.01) for both criteria tested. The median values for all groups were 100% for clinical acceptable margin and 0% for marginal opening. Conclusion: By using the universal bonding agent, high margin qualities on dentin and enamel are obtained with ceramic inlays even with the simplified approach. [ABSTRACT FROM AUTHOR]

Present work investigates the dynamics of polycrystalline quartz cement growth in sandstone using a multiphase-field model. First, the model parameters corresponding to common reservoir temperature and pressure conditions were determined. A parameter related to growth kinetics was ascertained through undisturbed cement growth simulations to aptly capture the known faceting-dependent growth behavior of quartz. Unrestricted growth simulations for different grain sizes, number of subgrains, and their crystallographic orientations revealed that (I) the model successfully recovers the tendency of quartz cements to grow at a faster overall rate on a coarse grain as compared to finer one and (II) the impact of crystallographic orientations of individual subgrains in polycrystalline grains on cement volume increases with increasing number of subgrains. For applying the model to realistic multigrain systems, we generated digital grain packs through a systematic procedure. These packs fairly represent natural sandstone in terms of grain shapes, sizes, and depositional porosity. The simulated textures in these packs resemble natural samples in terms of crystal morphologies and pore geometries. The cement growth rate decreases with the increase in fraction of polycrystalline grains, indicating a significant role of mutual hindrance among differently oriented overgrowths originating from different subgrains. Further, the permeabilities computed using fluid-flow simulations through the progressively cemented packs suggest that monocrystalline packs are more permeable than equally porous polycrystalline ones. The computed permeabilities of the simulated microstructures are consistent with the measured permeabilities, advocating the pack generation process and cementation modeling approach. [ABSTRACT FROM AUTHOR]

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Tin sludge produced during tin electroplating of steel sheet is an interesting secondary source of tin. Dried sludge usually contains more than 50% tin. Hydrometallurgical sludge treatment consists of several steps, including leaching in hydrochloric acid and electrolytic recovery of tin. The electrowinning process is negatively affected by the presence of impurities such as antimony and bismuth, which can cut overall current efficiency to 11% as well as reducing the quality of recovered tin. It is appropriate therefore to remove these impurities from the leachate before the electrowinning steps. This work studies the refining of leachate using cementation. The experiments were carried out at temperatures of 20, 40 and 60 °C at solid to liquid ratios of 1:60, 2:60, 3:60 and 4:60 using tin and iron dust as cementing metals. The leachates were mixed at a constant rate of 400 rpm during all cementation experiments. Effective removal of impurities was achieved in the case of iron powder cementation at s/l ratio 2:60 and temperature 20 °C. This cementation removed 98.49% bismuth and 99.14% antimony from the leachate solution. Electrolysis efficiency was increased from 11 to 71% after leachate refining. Antimony and bismuth were not detected in the final product obtained from refined electrolyte by means of electrolysis. [ABSTRACT FROM AUTHOR]

The mechanical behavior of porous sandstones is generally modeled using concepts from granular mechanics, often overlooking the effect of cementation. To probe the key differences between sand and sandstone mechanics, we performed triaxial deformation experiments on Ottawa quartz sand at 5‐ to 40 MPa effective confining pressure. At 5 MPa, the samples are able to dilate. At higher confinement, the aggregates show continuous compaction, displaying strain hardening. The stress‐strain behavior is nonlinear, and the exact onset of inelastic compaction could not be determined accurately. Measured P‐wave velocities show the development of anisotropy. With increasing axial strain, the along‐axis velocities tend to increase, while velocities perpendicular to the compression axis tend to decrease (at low pressure) or remain constant (at high pressure). In samples deformed under elevated pressure conditions, acoustic emission event locations are diffuse. Microstructural investigations show an increase in grain chipping and crushing with increasing confining pressure, but no evidence of localized compaction could be observed. The nature of the pore fluid, either decane or water, does not significantly influence the mechanical behavior at strain rates of 10−6 to 10−4 s−1. Grain angularity and grain‐size distribution also did not significantly change the mechanical behavior. We infer that our observations indicate that the lack of cementation introduces additional degrees of freedom for grains to slide, rotate, and reorganize at the sample scale, precluding the existence and sustainability of stress concentrations beyond the grain scale. This results in progressive compaction and hardening, and lack of compaction localization. Key Points: Compared to sandstone, sand deformation exhibits continuous yielding with progressive compaction and hardening, lacking strain localizationMost deformation is inelastic (80–95%), with minor grain chipping at low Pc and whole grain breakage at higher Pc, plus grain rearrangementLack of cementation allows for grain sliding, rotation and rearrangement, preventing stress concentrations to exist beyond the grain scale [ABSTRACT FROM AUTHOR]

Electrical anisotropy of rock is a key parameter in geophysical research. In this paper, digital rocks were constructed by aligning elliptic grains to create samples with anisotropic pore connectivities. Lattice gas automata are used to research electrical transport properties for revealing the anisotropy and physical meaning of Archie's cementation exponent. Simulated results indicate that the relationship between formation factor and porosity is of anisotropy with the exponent corresponding to the change rate of pore complexity with porosity, instead of pore complexity itself, confirming previous theoretical studies. Besides, the results reveal that anisotropy of pore structure is a main factor leading to the anisotropic relation. Under the effects of fracture, there is a U‐shape transition zone over a range of porosity for anisotropy exponent. Moreover, the simulated data are in good agreement with the laboratory experiments, which can further verify the validity of the results. Plain Language Summary: The anisotropy and physical meaning of Archie's parameters are of great interest to the research in geophysical domain. However, it is very difficult to investigate the mechanism employing only laboratory experiments due to the limits of current equipment and technology. In this letter, digital rock model can be constructed with different complexity of pore structure in different directions, and the complexity can be modified at pore scale to reveal the physical meaning of the cement exponent. Based on the models, lattice gas automata method is used to research electrical properties of porous media with the surface conduction of electrical double layer for matrix grains. Simulated results indicate that the relationship between formation factor and porosity is of anisotropy caused by anisotropic connectivity of pore space, which leads to the anisotropic cement exponent. Theoretical analysis and simulations indicate the cement exponent is actually a representation of the rate of change of pore complexity with porosity, instead of representing the pore complexity. Moreover, there is a U‐shape transition zone over a range of porosity for anisotropy exponent under effects of fracture. All the results can form the basis of developing a tensor model of rock physics. Key Points: Anisotropy of the relation between the formation factor and porosity has been investigated with the lattice gas automata methodThe cementation exponent m is of anisotropy with respect to the change of porosity and pore spacePore structure is a main factor leading to the electrical anisotropy [ABSTRACT FROM AUTHOR]

Studying the effects of the solid pore fills on the elastic properties of rocks is of significant importance for a range of applications, such as, for example, monitoring of heavy oil reservoirs or modeling the transport properties of the rocks affected by salt precipitation or cementation. We present the results of the laboratory solid‐substitution experiments carried out on Bentheim sandstone at a seismic frequency of 2 Hz. The experiments were performed when the pore space of the tested sample was filled sequentially with solid (23°C) and liquid (40°C) octadecane. Previously, ultrasonic measurements on the same octadecane‐filled sandstone showed significant discrepancy from the predictions of Ciz‐Shapiro theory, which was explained by the effect of stiffening of compliant pores at the grain contacts. However, the present results show good agreement with the predictions of the Ciz‐Shapiro theory and suggest that the effect of stiffening of the compliant pores in presence of solid is negligible at low frequency. Key Points: Laboratory measurements of the elastic moduli of a sandstone sample filled with solid octadecane are conducted at seismic frequencyThe measured drained moduli of the sample are verified using the Gassmann theoryThe low‐frequency experimental results corroborate the predictions of the Ciz‐Shapiro theory [ABSTRACT FROM AUTHOR]

Silicide coatings and B-modified silicide coatings were deposited on Nb-Si-based alloys by means of pack cementation method at 1573 K. The phase sequence of the coating/substrate system was investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron microprobe analysis (EPMA), respectively. The substrate is composed of (Nb, X)5Si3, Cr2Nb, and (Nb, X)ss phases (X is Ti, Cr, Hf, and Al). In addition, the silicide coating exhibits a multilayer microstructure, consisting of three layers, i.e., (Nb, X)Si2 → (Nb, X)Si2 + (Ti, Nb)5Si4 → (Ti, Nb)5Si4, whereas the B-modified silicide coating consists of a sequence of four layers, (Nb, X)B2 + (Nb, X)Si2 → (Nb, X)Si2 → (Nb, X)Si2 + (Ti, Nb)5Si4 → (Ti, Nb)5Si4. The diffusion paths for the two coating/substrate systems were thereafter elucidated by inspecting the Nb-Ti-Si-Cr and Nb-Si-Ti-B/Nb-Si-Ti-Cr multinary isotherms. Of technological interest, the diffusion path in the silicide coating was extended to predict and study the diffusion path in the Ge-modified silicide coating/substrate, which well describes the Nb-Ti-Cr-(Si, Ge) tetrahedral isotherm and phase behavior. This offers an indirect validation for the diffusion path in the silicide coating/substrate system. [ABSTRACT FROM AUTHOR]

Thermodynamically stable and non-reactive yttrium oxide is proposed to be the coating material on high-density graphite (HDG) crucible for melting and consolidating uranium in the pyrochemical reprocessing of spent metallic nuclear fuels. Yttria deposited over HDG by atmospheric plasma spray (APS) process without interlayer cannot withstand temperatures above 1400°C because of large thermal expansion mismatch and high-temperature partial oxidation of underlying graphite substrate through pores and openings in the plasma sprayed yttria layer. To overcome this limitation, a stable oxidation-protective intermediate layer of SiC was developed over graphite by conventional pack cementation process using two different precursor powders. The coated samples were characterized with respect to coating thickness, microstructure, and phase composition. Experimental results revealed that the optimum pack composition for obtaining thick and diffused coating was 70 wt. % Si - 20 wt. % C - 10 wt. % Al2O3. Subsequently, yttria top coat was deposited over pack cemented HDG coupons by APS process with optimized process parameters. The interlayer of SiC developed by pack cementation for yttria top coat facilitated to extend the thermal cycling life of the coating in inert argon environment significantly. The onset of micro-cracking in the top coat with SiC interlayer occurred after 45, 25 and 13 thermal cycles at 1400°C, 1450°C and 1500°C, respectively. [ABSTRACT FROM AUTHOR]

Biocementation of hazardous waste is used in reducing the mobility of contaminants, but studies on evaluating its efficacy have not been well documented. Therefore, to evaluate the efficacy of this method, physicochemical factors affecting stabilized hazardous products of in situ microbially induced calcium carbonate precipitation (MICP) were determined. The strength and leach resistance were investigated using the bacterium Pararhodobacter sp. Pb-contaminated kiln slag (KS) and leach plant residue (LPR) collected from Kabwe, Zambia, were investigated. Biocemented KS and KS/LPR had leachate Pb concentrations below the detection limit of < 0.001 mg/L, resisted slaking, and had maximum unconfined compressive strengths of 8 MPa for KS and 4 MPa for KS/LPR. Furthermore, biocemented KS and KS/LPR exhibited lower water absorption coefficient values, which could potentially reduce the water transportation of Pb2+. The results of this study show that MICP can reduce Pb2+ mobility in mine wastes. The improved physicochemical properties of the biocemented materials, therefore, indicates that this technique is an effective tool in stabilizing hazardous mine wastes and, consequently, preventing water and soil contamination. [ABSTRACT FROM AUTHOR]

An analytical study was performed on copper alloy objects and ingots/prills from Haft Tappeh Middle Elamite site, southwestern Iran, fourteenth century BC. The samples were analysed by micro-PIXE and SEM-EDS methods to characterise chemical composition and different phases in their microstructure. The results showed that the main objects' compositions are copper with impurities and variable-Sn containing tin bronze. Furthermore, most of the ingots/prills are composed of copper with high concentration of iron and sulphur while in two samples tin bronze ingot/prill is detected. Based on the results, the main metallurgical operation in Haft Tappeh may be matte production to make metallic copper and producing tin bronze alloy probably by cementation. [ABSTRACT FROM AUTHOR]

A novel pack-aluminizing diffusion coating has been conducted on -Inconel 718 alloy at 600 and 650°C for 2 and 4 h. The aluminising powder packs have been prepared using Al powder as a source for depositing aluminium, Al2O3 powder as an inert filler and ammonium chloride NH4Cl as an activator. The microstructures of the coatings formed on the alloy surface are characterized by means of SEM/EDS and XRD analysis. Optical microscope and SEM analysis reveal that coating layers are homogenous, compact and nonporous and there is a good bonding at the interface of the coating and matrix. Layer thickness variation is measured from the surface to the matrix and changed from 10 to 40 m which is increased with increasing process time and temperature. The hardness of the coating layer increased to 1174 HVN with the increasing process time and the temperature while the hardness of the matrix is 300 HVN. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) discrete element method (DEM)-based numerical model is used to simulate the macromechanical response of sand strengthened using microbially induced carbonate precipitation (MICP) under undrained triaxial compression and inform the particle-scale mechanisms responsible for the behavior. The constant volume method is used to simulate saturated media. Although simulations using rigid boundaries are capable of representing the response of uncemented sands, virtual undrained triaxial tests on cemented sands require the use of flexible boundaries. Flexible membrane boundaries are created using particle facets (PFacets) as the building blocks. A methodology to implement virtual undrained triaxial compression using PFacet-based membrane boundaries is developed. The macroscale response of sands with varying degrees of cementation is adequately captured by this model. A cohesive bond strength, used to express the degree of cementation, is found to be well related to the shear-wave velocity through the soil sample. The model correctly predicts the occurrence of strain localization in cemented media, and the expected trends in shear band formation. The evolution of normal contact force distributions and coordination numbers as functions of both the cementation level and axial strain are also predicted. [ABSTRACT FROM AUTHOR]

Purpose This study aims to apply the pack cementation to develop the Fe-Al layers on the surface of FC 25 cast iron in order to increase the high-temperature corrosion resistance of the alloy.Design/methodology/approach Pack cementation was applied on the surface of FC 25 cast iron at 1,050°C. The bare and aluminised alloys were subjected to the oxidation test in 20 per cent O2-N2 at 850 °C. Scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD) were used for characterisation.Findings The layers of pack cementation consisted of Fe2Al5, FeAl2 and FeAl, and solid solution alloyed with Al. The oxidation kinetics of the bare cast iron was parabolic. Mass gain of the aluminised cast iron was significantly decreased compared with that of the bare cast iron. This was because of the protective alumina formation on the aluminised alloy surface. Al in the Fe–Al layer also tended to be homogenised during oxidation.Originality/value Even though the aluminising of alloys was extensively studied, the application of that process to the FC 25 cast iron grade was originally developed in this work. The significantly reduced mass gain of the aluminised FC 25 cast iron makes the studied alloy be promising for the use as a valve seat insert in an agricultural single-cylinder four-stroke engine, which might be run by using a relatively cheaper fuel, i.e. LPG, but as a consequence requires the higher oxidation resistance of the engine parts. [ABSTRACT FROM AUTHOR]

A closed-loop regeneration process for value-added recycling of spent LiFePO 4 batteries. [Display omitted] • Efficient separation of Li/Fe/P elements from graphite powder is achieved by hot-acid leaching. • Iron powder cementation is used to recover high grade sponge copper from acid leachate. • Al and F are precipitated in the form of AlPO 4(s) and FeF 3(s) at pH = 3.75. • LiFePO 4 precursors are obtained with co-precipitation method at pH = 8-9. • LiFePO 4 /C materials with good electrochemical properties are regenerated by calcination method. A closed-loop regeneration route to recover valuable elements from spent LiFePO 4 batteries is proposed. After hot-acid leaching, the leaching rates of Li, Fe and P are above 99.8 %, and the graphite powder retain in the residue with grade of 93.33 %. With iron powder cementation, 99.96 % Cu is removed from acid leaching solution to obtain sponge copper. And then 96.67 %Al and 89.30 %F are precipitated in the form of AlPO 4(s) and FeF 3(s) at pH = 3.75. Li, Fe and P within the purified solution are prepared as LiFePO 4 precursors by co-precipitation method, and finally LiFePO 4 /C materials are synthesized after two-stage calcination. The recycled LiFePO 4 /C materials demonstrate excellent electrochemical performance with a discharge capacity of 153.1 mAh·g−1 at 0.1C and a capacity retention of 94.0 % after 500 cycles at 1C. The present recycling process provides a strategy for short and efficient regeneration of spent LiFePO 4 batteries. [ABSTRACT FROM AUTHOR]

Abstract The cementation complex of Las Viñas (SW Spain) is a partially reclaimed abandoned mine site located in the drainage basin of a water reservoir currently under construction. The aim of this investigation was to analyze these mine soils to evaluate their potential environmental impact, especially on the final reservoir water quality. Results evidence the extremely high acidity of soils (pH of 3.4 and maximum potential acidity of 47 kg CaCO 3 /ton), with high concentrations of trace elements, especially As, Pb and Cu. Sequential extraction data reveal the potential release of significant quantities of Mn, Cd, Cu and other easily-soluble trace elements by rainfalls. The weathering and transport of soils to the bottom sediments of the planned reservoir could lead to the release of significant quantities of toxic trace elements to the water column if anoxic (mainly As, Sb, Cr, Ni, Cu and Pb) or oxic (mainly Hg, Pb, V, Cu and As) conditions are found in the sediments. The acidity and metals released from these soils could jeopardize the quality of the reservoir waters. Remediation measures must be therefore adopted, focused on the cleanup and liming of soils in order to promote colonization and vegetation succession, thus avoiding soil erosion and limiting metal release to the hydrosphere. This study proposes the use of different low-cost materials to improve the soil quality, limiting the metal transfer to the planned reservoir water. The information contained in this study could be of great importance in other watersheds affected by abandoned mine sites. Graphical abstract Image 1 Highlights • Soils affected by mining exhibit an acidic nature and high metal concentrations. • Eroded materials may be deposited in the bottom sediments of a planned water reservoir. • This study evidences a high potential metal/loid release from soils to the reservoir water column. • Different low-cost materials are proposed to limit the metal/loid transfer. [ABSTRACT FROM AUTHOR]

Highlights • Several Y modified silicide coatings were prepared on the Ti-Al-Nb-Zr alloys. • The Zr contents in the alloys have a significant influence on the coating structure. • Adding 2 at.% Zr can facilitate the formation of a dense SiO 2 layer. • Excessive Zr in the coating will lead to the deterioration of the scale adhesion. Abstract Modified silicide coatings were prepared on Ti-5Al-10Nb- x Zr (x = 0, 2, 5, 10, 15 and 20 at.%) alloys by pack cementation process. The effects of Zr content on the coating structure and oxidation resistance have been investigated. With increasing Zr contents in the substrate, the coating structure shows a significant change. Adding 2 at.% Zr can improve the oxidation resistance of silicide coating due to the formation of a thin and dense SiO 2 layer. But excessive Zr exerts an adverse influence on the oxidation resistance due to the volume expansion caused by the phase transformation of ZrO 2 during the oxidation process. [ABSTRACT FROM AUTHOR]

Abstract In order to improve the oxidation resistance of C f /Cs produced by chemical vapour infiltration, a multilayer coating based on silicon carbide and molybdenum disilicide was produced by two-step pack cementation technique. The inner SiC layer with a thickness up to 25 μm was obtained without promoted reaction additives by varying the composition, and thermal treatment conditions. The SiC/SiC-MoSi 2 coating was produced with a thickness up to 80 μm by two step pack cementation, considering the effect of the inner layer characteristic. The enhancement of the oxidation resistance, observed in SiC/SiC-MoSi 2 coated C f /Cs by means of thermal analysis in flowing air up to 1500 °C, was due to the formation of SiO 2 promoted by the passive oxidation of silicon carbide and molybdenum disilicide. [ABSTRACT FROM AUTHOR]

Tin isotope ratios may be a useful tool for tracing back the tin in archaeological metal artefacts (tin metal, bronze) to the geological source and could provide information on ancient smelting processes. This study presents the results of laboratory experiments, which reduced (smelted) synthetic stannic oxide, natural cassiterite and corroded archaeological tin and bronze objects. The overall aim of the study is to find a reliable method for the decomposition of tin ores and corrosion products in order to determine their tin isotopic composition, and to explore possible effects on the tin isotope ratios during pyrometallurgy. We focused on five methods of reduction at high temperatures (900-1100 °C): reduction with CO (plain smelting), reduction with KCN/CO (cyanide reduction), reduction with Na2CO3/CO, reduction with Cu/CO ('cementation technique') and reduction with CuO/CO ('co-smelting'). The smelting products are analysed by means of optical and scanning electron microscopy as well as X-ray diffraction, while their isotope composition is determined with a high-resolution multi-collector mass spectrometer with inductively coupled plasma ionisation. The results show that all five methods decompose synthetic stannic oxide, cassiterite and corrosion products. Ultimately, reduction with KCN is the best solution for analysing tin ores and tin corrosion because the chemical processing is straightforward and it provides the most reproducible results. Reduction with Na2CO3 and copper is an alternative, especially for bronze corrosion, but it requires laborious chemical purification of the sample solutions. In contrast, evaporation of tin and incomplete alloying during plain smelting and co-smelting can cause considerable fractionation among smelting products (Δ124Sn = 0.10 ‰ (0.03 ‰ u−1)). A less precise and even inaccurate determination of the tin isotopic compositions of the tin ores would be the consequence. However, the results of this study help to evaluate the possible influence of the pyrometallurgical processes on the tin isotope composition of tin and bronze artefacts. [ABSTRACT FROM AUTHOR]

Mishrif carbonates formation, is a major reservoir in southeast of Iraq and is one of the principle carbonate reservoir in central and southern Iraq, which is of Late Cenomanian to Early Turronian. A petrographic and depositional Environment study has been carried out by examining available thin sections in the Ministry of Oil for wells (No-1, No-2 (Noor field), Am-1(Amara field) and Hf-1 (Halfaya field)). The main skeletal grains of the Mishrif formation include coral, Rudist, large and small benthonic Foraminifera & planktonic Foraminifera (Planktonic Foraminifera are common in the lower part of the Mishrif Formation), ostracods, echinoderms, and molluscs. The Rudist were found in small to large fragments; and as a complete fossil covering the whole thin section. The Non-skeletal grains included peloids, and micrite. The most important diagenetic processes affecting on the Mishrif Formation are dolomitization, dissolution, cementation, micritization, recrystallization and Stylolite.Mishrif succession comprises six paleoenvironments which are deep marine, shallow open marine, rudist biostrome, shoal, back shoal, and lagoon. [ABSTRACT FROM AUTHOR]

Highlight • The cementing ability of recycled hardened cement paste powder (RHCPP) can be regenerated by autoclave carbonation. • Carbonated RHCPP blocks exhibited compressive strength high than 60 MPa. • Factors affecting the compressive strengths of carbonated RHCPP blocks are revealed. Abstract Well-hydrated cement paste powder was prepared to imitate recycled hardened cement paste powder. Compacted blocks were formed with the powder, and subjected to carbonation at different CO 2 pressures. The effects of water/powder (w/p) ratio and compacting pressure in block preparation, and the CO 2 pressure on the carbonation degree and compressive strength of the carbonated blocks were studied. The mineral compositions, microstructures and pore structures of the carbonated blocks were analyzed by XRD, SEM and MIP. The results show that the hardened cement paste powder in the blocks is able to re-cement and produce high level strength by carbonation. In the CO 2 pressure range of 0.05–0.40 MPa, the higher the CO 2 pressure was, the higher the carbonation degree and compressive strength of the blocks at all the carbonation times. Carbonated blocks with the compressive strength as high as 62.6 MPa were prepared by carbonation in 0.4 MPa CO 2 for 24 h. The calcium hydroxide, calcium silicate hydrates and the un-hydrated β-C 2 S in the hardened cement paste powder were almost fully carbonated in 24 h. There was no new well-crystallized mineral other than the three polymorphs of calcium carbonate, mainly calcite, formed during the carbonation. The microstructures became more compacted due to the filling of the pores by CaCO 3 and the other carbonation products such as low calcium silicate hydrates, companied with the decrease of the porosity and the pore sizes. [ABSTRACT FROM AUTHOR]

Abstract Purpose The objective of this study was to evaluate the effect of primer-cement systems with different functional phosphate monomers on the adhesion of zirconia to dentin with and without aging protocols. Materials and methods Bovine teeth (N = 180) were embedded in acrylic resin after sectioning their roots with with their coronal parts exposed. The buccal surface of each tooth was polished with silicon carbide papers (#200, 400, 600) until dentin exposure. Sintered zirconia cylinders (N = 180) (Ø: 3.4 mm; height: 4 mm) (Vita In-Ceram 2000) were prepared and distributed into 18 groups (n = 10 per group) considering the following factors: "Cementation System" (Panavia F - PAN; RelyX Ultimate - ULT, Multilink N - MULT) and "aging" (water storage in distilled water at 37 °C for 24 h (control, C); 30 days (30D); 6 months (6 M) and thermocycling for 5000 (5TC), 10,000 (10TC) and 20,000 (20TC) thermal cycles (5–55 °C; dwell time: 30 s)". Zirconia and dentin cementation surfaces were conditioned according to the recommendations of the manufacturers of each resin cement. The cylinders were adhesively cemented to the dentin surfaces and the specimens were submitted to the aging protocols. After aging, the specimens were subjected to shear bond strength test (SBS) (1 mm/min) in a Universal Testing Machine and failure types were analyzed. The data (MPa) were statistically using Kruskal-Wallis followed by the Dunn test (α = 5%). The degree of conversion (DC) rates of the cementing systems were also measured. Results While without aging (24 h) no significant difference was found between the cement systems (p > 0.05), after 30D (4.3–5.4), the highest decrease in all groups were observed after 5TC (1.5–2.3) (p < 0.05). Overall, MULT and ULT presented significantly higher results than that of PAN (p < 0.05). Pre-test failures during TC were more frequent in the PAN group. Complete adhesive failures at the cement/dentin interface were more frequent for MULT (30–80%) and PAN (10–70%) and for ULT (20–90%) at the cement/ceramic interface. DC of the tested cements did not show significant difference. Conclusion Adhesion performance of the primer-cement systems with different functional phosphate monomers on zirconia-dentin complex varied as a function of aging strategies with MULT and ULT delivering higher bond strength values. When failure types considered, none of the cement systems performed well on both ceramic and dentin. [ABSTRACT FROM AUTHOR]

Abstract A new process involving low-temperature pack cementation, sol-gel and electrodeposition methods was developed to prepare aluminide bond coat/zirconia composite coatings. The morphology and phase structure of the bond coat and ZrO 2 coating were examined by scanning electron microscope equipped with energy dispersive spectroscopy, thermogravimetric/differential thermal analysis and X-ray diffraction. The thermal shock resistance was further studied. The results revealed that the bond coat contained Fe 3 Al, FeAl, Fe 2 Al 5 and FeAl 3 phases and had a surface roughness of about 2.641 μm. Pore structure was observed on the surface of ZrO 2 film after sol-gel process, while dense surface without pores was detected after electrodeposition. The annealing temperature had an important influence on the surface morphology and phase structure of the ZrO 2 coating. In addition, the coating showed a good thermal shock resistance without peeling off after 40 thermal cycles. Graphical abstract Unlabelled Image Highlights • An aluminide/zirconia composite coating is prepared by a combined process. • The aluminide bond coat has a surface roughness of about 2.641 μm. • The ZrO 2 films after sol-gel have a porosity ranging from 3.59% to 7.85%. • The ZrO 2 coating after electrodeposition has microcracks on the surface. • No peeling off occurs after 40 thermal cycles of the ZrO 2 coating. [ABSTRACT FROM AUTHOR]

Abstract A NbSi 2 /SiO 2 -Nb 2 O 5 multilayer coating, consisting of a NbSi 2 inner layer and a SiO 2 -Nb 2 O 5 outer layer, was prepared on Nb alloy through halide activated pack cementation (HAPC) and microarc oxidation (MAO). The hot corrosion behaviors of the single NbSi 2 coated and the NbSi 2 /SiO 2 -Nb 2 O 5 coated Nb alloys were comparatively investigated with a mixture of Na 2 SO 4 /NaCl (3:1 wt.%) salt at 900 °C. The growth kinetics of the corroded scales follow the parabolic laws, and the parabolic rate constants of the NbSi 2 coated and the NbSi 2 /SiO 2 -Nb 2 O 5 coated specimens were 2.16 × 10−3 mm s−2 and 1.04 × 10−3 mm s−2, respectively. During the corroding process, the SiO 2 -Nb 2 O 5 outer layer that serves as a barrier promotes the formation of continuous SiO 2 scale, and isolates the NbSi 2 layer from the corrosion salt. The lower corrosion rate of the NbSi 2 /SiO 2 -Nb 2 O 5 coated specimens is attributed to the formation of the protective SiO 2 corroded scale. Graphical abstract Image 1 Highlights • A multilayer coating was formed on Nb alloy by HAPC combined with MAO. • The coating consists of a SiO 2 -Nb 2 O 5 ceramic outer layer and a NbSi 2 inner layer. • The coated Nb alloys shows superior hot corrosion resistance due to SiO 2 -Nb 2 O 5 layer. • The superior hot corrosion resistance is due to formation of glassy corroded scale. [ABSTRACT FROM AUTHOR]

In order to analyze variable-mass permeation characteristics of broken rock mass under different cementation conditions and reveal the water inrush mechanism of geological structures containing broken rock masses like karst collapse pillars (KCPs) in the coal mine, the EDEM-FLUENT coupling simulation system was used to implement a numerical simulation study of variable-mass permeation of broken rock mass under different cementation conditions and time-dependent change laws of parameters like porosity, permeability, and mass loss rate of broken rock specimens under the erosion effect were obtained. Study results show that (1) permeability change of broken rock specimens under the particle migration effect can be divided into three phases, namely, the slow-changing seepage phase, sudden-changing seepage phase, and steady seepage phase. (2) Specimen fillings continuously migrate and run off under the water erosion effect, porosity and permeability rapidly increase and then tend to be stable, and the mass loss rate firstly rapidly increases and then gradually decreases. (3) Cementation degree has an important effect on permeability of broken rock mass. As cementing force of the specimen is enhanced, its maximum mass loss rate, mass loss, porosity, and permeability all continuously decrease. The study approach and results not only help enhance coal mining operations safety by better understanding KCP water inrush risks. It can also be extended to other engineering applications such as backfill paste piping and tailing dam erosion. [ABSTRACT FROM AUTHOR]

Features of gold cementation from cyanide solutions with electrolytic zinc powder are studied. The test powders are prepared by electro-extraction of alkaline solutions after leaching zinc-containing dust. Cementation is conducted in two regimes: under pressure (Merrill-Crowe process) and a fluidized bed regime. It is established that with respect to degree of gold extraction and specific consumption of test dendritic powder it is no worse or surpasses powders prepared by vapor condensation used traditionally in the gold extraction industry. The features established may be explained by physical features of powders prepared by electro-extraction from alkaline solutions. [ABSTRACT FROM AUTHOR]