Cementitious Compositions

The invention provides a cementitious composition comprising a cement component comprising (i) an accelerant, (ii) a calcium sulphate source and (iii) an ettringite forming cement; an aggregate; and optionally water; wherein the cement has a minimum unconfined compressive strength of 1500 psi when tested in accordance with ASTM C1140 and/or C1604 at 15 minutes after placement; methods for its use and concrete formed from it

Hybrid Cement Clinker and Cement Made from That Clinker

A hybrid cement clinker incorporates specific ranges of clinker phases and falls within specific modulus values as set forth and described in this document

Interfacial Bond between Reinforcing Fibers and Calcium Sulfoaluminate Cements: Fiber Pullout Characteristics

The results of an experimental investigation on the influence of the interfacial bond of reinforcing fibers embedded in a calcium sulfoaluminate matrix on the fiber-pullout peak load and energy consumption are presented. Bonding at the fiber-matrix interface plays an important role in controlling the mechanical performance of cementitious composites—in particular, composites formed from sulfate-based systems (calcium sulfoaluminate [CSA] cements), as opposed to the silicate systems found in portland cement. Various types of fibers were selected, including polyvinyl alcohol (PVA), polypropylene, and copper-coated steel. The fibers were embedded in three different matrixes: two sulfate-based cements including one commercially available CSA cement and a CSA fabricated from coal-combustion by-products. The third matrix was a silicatebased ordinary portland cement (OPC). In this study, the results of the single-fiber pullout test were coupled with scanning electron microscopy (SEM) to examine the interfacial bond between the fiber and CSA matrix for evidence of debonding and possible hydration reaction products

Facile Synthesis and Characterization of Pure Tochilinite‐like Materials from Nanoparticulate FeS

Abstract In this work, three different tochilinite‐like materials have been obtained by sophisticated synthetic methods that allow to control the distribution of iron ions. The purity of the samples was confirmed by powder X‐ray diffraction. From elemental analysis and Mössbauer spectroscopy data, detailed compositions could be determined: T1) Fe 0.76 S*0.86 [Fe 2+ 0.01 Fe 3+ 0.56 Mg 2+ 0.43 (OH) 2.01 ]; T2) Fe 0.89 S*0.85 [Fe 2+ 0.55 Fe 3+ 0.11 Al 3+ 0.33 (OH) 1.84 (O) 0.16 ]; T3) Fe 0.71 S*0.79 [Fe 2+ 0.25 Fe 3+ 0.73 Mg 2+ 0.01 Al 3+ 0.01 (OH) 1.98 (O) 0.02 ]. These compositions fit to typical compositions of tochilinite in regard of the amount of iron vacancies and the volume ratio of the hydroxide layers to the sulfide layers. Besides hydroxide ions, oxide ions are also present in the hydroxide layers as a result of surface oxidation after the synthesis due to the high reactivity of the particles. TEM and SEM investigations show that the obtained powders consist mainly of thin sheets accompanied by nanotubes with BET surface areas ranging between 20 m 2 /g and 40 m 2 /g. The thermal stability was investigated by TGA and DSC analysis and it depends significantly on the composition.imag

Ni-P: Microstructure and micro-compression

Electroless nickel-phosphorus (EN-P) plating is a popular deposition process with widespread applications in microelectronics [1, 2]. Much emphasis has been given on the plating process and on the physical and chemical properties of the EN-P layers; however their mechanical properties down to the sub-micrometer dimensions have not been elucidated systematically. In this work, we study the mechanical properties of EN-P as a function of annealing states using in-situ pillar compression technique [3]. Please click Additional Files below to see the full abstract

Altered expression of genes controlling metabolism characterizes the tissue response to immune injury in lupus.

To compare lupus pathogenesis in disparate tissues, we analyzed gene expression profiles of human discoid lupus erythematosus (DLE) and lupus nephritis (LN). We found common increases in myeloid cell-defining gene sets and decreases in genes controlling glucose and lipid metabolism in lupus-affected skin and kidney. Regression models in DLE indicated increased glycolysis was correlated with keratinocyte, endothelial, and inflammatory cell transcripts, and decreased tricarboxylic (TCA) cycle genes were correlated with the keratinocyte signature. In LN, regression models demonstrated decreased glycolysis and TCA cycle genes were correlated with increased endothelial or decreased kidney cell transcripts, respectively. Less severe glomerular LN exhibited similar alterations in metabolism and tissue cell transcripts before monocyte/myeloid cell infiltration in some patients. Additionally, changes to mitochondrial and peroxisomal transcripts were associated with specific cells rather than global signal changes. Examination of murine LN gene expression demonstrated metabolic changes were not driven by acute exposure to type I interferon and could be restored after immunosuppression. Finally, expression of HAVCR1, a tubule damage marker, was negatively correlated with the TCA cycle signature in LN models. These results indicate that altered metabolic dysfunction is a common, reversible change in lupus-affected tissues and appears to reflect damage downstream of immunologic processes

Nucleic Acid-Sensing and Interferon-Inducible Pathways Show Differential Methylation in MZ Twins Discordant for Lupus and Overexpression in Independent Lupus Samples: Implications for Pathogenic Mechanism and Drug Targeting.

Systemic lupus erythematosus (SLE) is a chronic, multisystem, autoimmune inflammatory disease with genomic and non-genomic contributions to risk. We hypothesize that epigenetic factors are a significant contributor to SLE risk and may be informative for identifying pathogenic mechanisms and therapeutic targets. To test this hypothesis while controlling for genetic background, we performed an epigenome-wide analysis of DNA methylation in genomic DNA from whole blood in three pairs of female monozygotic (MZ) twins of European ancestry, discordant for SLE. Results were replicated on the same array in four cell types from a set of four Danish female MZ twin pairs discordant for SLE. Genes implicated by the epigenetic analyses were then evaluated in 10 independent SLE gene expression datasets from the Gene Expression Omnibus (GEO). There were 59 differentially methylated loci between unaffected and affected MZ twins in whole blood, including 11 novel loci. All but two of these loci were hypomethylated in the SLE twins relative to the unaffected twins. The genes harboring these hypomethylated loci exhibited increased expression in multiple independent datasets of SLE patients. This pattern was largely consistent regardless of disease activity, cell type, or renal tissue type. The genes proximal to CpGs exhibiting differential methylation (DM) in the SLE-discordant MZ twins and exhibiting differential expression (DE) in independent SLE GEO cohorts (DM-DE genes) clustered into two pathways: the nucleic acid-sensing pathway and the type I interferon pathway. The DM-DE genes were also informatically queried for potential gene-drug interactions, yielding a list of 41 drugs including a known SLE therapy. The DM-DE genes delineate two important biologic pathways that are not only reflective of the heterogeneity of SLE but may also correlate with distinct IFN responses that depend on the source, type, and location of nucleic acid molecules and the activated receptors in individual patients. Cell- and tissue-specific analyses will be critical to the understanding of genetic factors dysregulating the nucleic acid-sensing and IFN pathways and whether these factors could be appropriate targets for therapeutic intervention

Alite calcium sulfoaluminate cement: chemistry and thermodynamics

Calcium sulfoaluminate (C$A) cement is a binder of increasing interest to the cement industry and is undergoing rapid development. Current formulations do not contain alite; however, alite calcium sulfoaluminate (a-C$A) cements can combine the favourable characteristics of Portland cement (PC) with those of C$A cement while also having a lower carbon dioxide footprint than the current generation of PC clinkers. This paper presents two results on the formation of a-C$A clinkers. The first is a thermodynamic study demonstrating that the production of a-C$A clinker is possible without the use of mineralisers, doping with foreign elements, or using multiple stages of heating. It is established that a-C$A clinker can be readily produced in a standard process by controlling the oxygen and sulfur dioxide fugacity in the atmosphere. This allows for the stabilisation of ye’elimite to the higher temperatures required for alite stability. The second result establishes that when using fluorine to mineralise a-C$A clinker production, the iron content in the clinker is also an important variable. Although the exact mechanism of alite stabilisation is not known, it is shown that alite formation increases with the combination of calcium fluoride and iron (III) oxide in the mix