Cellular sprayed concrete for simple and economic remixing

The development of various supplementary cementitious materials (SCMs) and chemical admixtures, makes the manufacturing of high-performance shotcrete possible. The most important SCM in high-performance shotcrete is silica fume because of its effect on pumpability, high-strength and durability which lies in its Pozzolanic reaction. Furthermore, the very small particle size of silica fume reacts more quickly than other SCMs and acts as a filler which contributes to the nano-sized porosity occurring in the interfacial transition zone. On the other hand, because of the extremely small particle size of silica fume, it is used as a pre-blended type with a Portland cement for a better distribution of silica fume in concrete. This results in a high cost material. If it is possible to distribute the very fine silica fume in a ready-mixed concrete, this would results in a very simple and an economic way. A very innovative method, which was named as Cellular sprayed concrete, was developed. Cellular sprayed concrete is a process to produce a High-Performance Concrete (HPC) by adding cellular and silica fume in ready-mixed concrete. This method enable to distribute the very fine silica fume in a ready-mixed concrete. This paper describe on the very new and innovative concept and procedures of cellular sprayed concrete

Application of cellular sprayed concrete into two-lift concrete

Two-lift concrete paving involves placing two layers of concrete \u27wet-on-wet\u27 instead of the traditional method of using a single homogeneous layer of concrete. The thick bottom layer offers the opportunity to optimize the use of local aggregates, recycled materials to produce an economical, durable, and sustainable pavement system with the most desirable surface characteristics like improved skid resistance and reduced noise provided by the high-quality surface of the high-performance concrete. The time between placing layers is often no more than 30 minutes. Perhaps the challenge involved in the construction of two-layer concrete systems includes the additional costs and logistics required for two plants to produce different concrete mixtures and two slip-form paver for paving both of bottom and top layers. A very simple and economic method for remixing an ordinary Portland cement concrete (OPC) into a high performance concrete (HPC) at a job site was developed, which is called \u27Cellular sprayed concrete\u27. Cellular sprayed concrete is produced by incorporating a preformed foam and fine powders in a ready mixed concrete and is conveyed under pressure through a pneumatic hose or pipe and projected into place at high velocity, with simultaneous compaction. This method can solve the problem of two batch plants and two pavers in 2LCP construction. \u27Cellular sprayed concrete\u27 enable utilizing a single batch plant for constructing 2-lift concrete pavement instead of 2 batch plants. This paper describes an extra ordinary application of sprayed concrete into concrete pavement

Plastic Shrinkage Properties of Natural Fiber Reinforced Shotcrete

Recently, natural hemp fibers have been developed for use in wet or dry mix shotcrete instead of conventional synthetic fibers made from petroleum. Synthetic fibers, which is mainly in polypropylene, has been used for controlling an initial shrinkage cracking in concrete, however, the effect was poor showing a severe plastic shrinkage cracking. Plastic shrinkage cracking is a nonstructural crack that occurs due to the surface drying of concrete in a plastic condition due to rapid evaporation of bleeding water. The volume reduction due to plastic shrinkage and the resulting tensile stress exceeds the tensile strength of the concrete. In particular, plastic shrinkage cracking occurs mainly in large surface area members. It may be evolved from the surface to a considerable depth, or in the case of a very thin structure, it may go all over the depth of the member. In addition, since it is long enough to be easily distinguished by naked eyes and cracks are generated widely, it is not aesthetically pleasing and anxiety about the stability of the concrete can be increased. Also, the plastic shrinkage crack accelerates penetration of chloride and moisture, causing corrosion of the reinforcing bar, and durability of the concrete is lowered. The theoretical effect of natural fibers on plastic shrinkage cracks is that when natural fibers are mixed into concrete, they become wet by absorbing the water. Then, in the pumping, water in the wet natural fiber is supplied to the concrete by the pumping pressure to increase the pumpability. Re-absorbing the water after spraying increases the adhesion and build-up thickness. The absorbed water could be supplied to the shotcrete and resulted in reducing a plastic shrinkage and dry shrinkage. This paper investigates the plastic shrinkage properties of shotcrete containing natural fibers. A series of experimental program were conducted to analysis the theoretical background and to select the optimized natural fiber content

MicroRNA-29a suppresses the growth, migration, and invasion of lung adenocarcinoma cells by targeting carcinoembryonic antigen-related cell adhesion molecule 6

AbstractCarcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is an important regulator of cell adhesion, invasion, and metastasis. The aim of this study was to evaluate the functional roles of CEACAM6 in lung adenocarcinoma and to identify miRNAs that inhibit the growth, migration, and invasion of lung adenocarcinoma cells by targeting CEACAM6. CEACAM6 expression is associated with poor prognosis of patients with lung adenocarcinoma, and CEACAM6 has important functional roles in controlling the growth, migration, and invasion of lung adenocarcinoma cells in vitro and in vivo. Furthermore, miR-29a can suppress the growth, migration, and invasion of lung adenocarcinoma cells by targeting CEACAM6. Therefore, miR-29a/CEACAM6 axis represents a potential therapeutic target for treatment of lung adenocarcinoma

Barrier protection via Toll-like receptor 2 signaling in porcine intestinal epithelial cells damaged by deoxynivalnol

Additional file 2. IPEC-J2 cells pretreated with TLR2 ligand maintained the expression of MCP-1, GM-CSF and TLR2 against DON exposure. IPEC-J2 cells pretreated with or without TLR2 ligand for 24 h were exposed to DON. (A) The bar graph showed the mRNA levels of porcine mcp-1, gm-csf measured using real time-PCR at 1 and 6 h after DON exposure (n = 3). (B) The mRNA levels of porcine tlr2 were measured using real-time quantitative PCR analysis at 6 h. NT represents no treatment. Expression of each mRNA was presented relative to the expression of housekeeping gene, gapdh (n = 3). *P < 0.05; **P < 0.01; ***P < 0.001, determined by one-way ANOVA with Tukey’s posttest

Input of terrestrial organic matter linked to deglaciation increased mercury transport to the Svalbard fjords

Deglaciation has accelerated the transport of minerals as well as modern and ancient organic matter from land to fjord sediments in Spitsbergen, Svalbard, in the European Arctic Ocean. Consequently, such sediments may contain significant levels of total mercury (THg) bound to terrestrial organic matter. The present study compared THg contents in surface sediments from three fjord settings in Spitsbergen: Hornsund in the southern Spitsbergen, which has high annual volume of loss glacier and receives sediment from multiple tidewater glaciers, Dicksonfjorden in the central Spitsbergen, which receives sediment from glacifluvial rivers, and Wijdefjorden in the northern Spitsbergen, which receive sediments from a mixture of tidewater glaciers and glacifluvial rivers. Our results showed that the THg (52 +/- 15 ng g(-1)) bound to organic matter (OM) was the highest in the Hornsund surface sediments, where the glacier loss (0.44 km(3) yr(-1)) and organic carbon accumulation rates (9.3 similar to 49.4 g m(-2) yr(-1)) were elevated compared to other fjords. Furthermore, the delta C-13 (-27 similar to -24 parts per thousand) and delta S-34 values (-10 similar to 15 parts per thousand) of OM indicated that most of OM were originated from terrestrial sources. Thus, the temperature-driven glacial melting could release more OM originating from the meltwater or terrestrial materials, which are available for THg binding in the European Arctic fjord ecosystems.11Ysciescopu

Critical organizational success factors for public private partnership projects – a comparison of solicited and unsolicited proposals

Public Private Partnership (PPP) projects are typically initiated through solicited or unsolicited proposals. The difference between the processes according to the proposal mode often leads to different levels of involvement and responsibilities for the public and private sectors. However, no robust research exists to capture the differences, depending on the proposal mode, in the roles and involvement of project participants and the impact of those differences on project success. This study intends to explore the critical organizational success factors contributing to the success of PPP projects according to the proposal mode and to provide practical recommendations for project success from organizational perspectives. To assess the factors, 141 questionnaire surveys were conducted with participants in 32 PPP projects. The major findings indicated that “Project Implementation Capability” had the most critical influence on solicited projects, whereas “Risk Sharing and Mitigation Strategies” was the most significant in unsolicited projects. In addition, “Interorganization Coordination” among project participants was essential to the success for both solicited and unsolicited projects. Government roles and involvement were also critical, although their contributions were relatively less important than other critical organizational success factors. Based on the findings, practical recommendations were provided for the success of solicited and unsolicited projects

Arterial Injury Associated with Tension-Free Vaginal Tapes-SECUR Procedure Successfully Treated by Radiological Embolization

Various postoperative complications have been reported after the use of tension-free vaginal tapes (TVT). The transobturator approach was introduced to minimize the potential complications. The next generation of recently introduced TVT-SECUR is intended to minimize the incidence of complications. Herein we report a case of internal pudendal artery injury sustained during this procedure that was successfully treated by radiological embolization. Angiography with vessel embolization, when available, should be considered when the arterial injury is suspected

Long-Term Cumulative Exposure to High γ-Glutamyl Transferase Levels and the Risk of Cardiovascular Disease: A Nationwide Population-Based Cohort Study

Background Elevated γ-glutamyl transferase (γ-GTP) levels are associated with metabolic syndrome. We investigated the association of cumulative exposure to high γ-GTP with the risk of cardiovascular disease (CVD) in a large-scale population. Methods Using nationally representative data from the Korean National Health Insurance system, 1,640,127 people with 4 years of consecutive γ-GTP measurements from 2009 to 2012 were included and followed up until the end of 2019. For each year of the study period, participants were grouped by the number of exposures to the highest γ-GTP quartile (0–4), and the sum of quartiles (0–12) was defined as cumulative γ-GTP exposure. The hazard ratio for CVD was evaluated using the Cox proportional hazards model. Results During the 6.4 years of follow-up, there were 15,980 cases (0.97%) of myocardial infarction (MI), 14,563 (0.89%) of stroke, 29,717 (1.81%) of CVD, and 25,916 (1.58%) of death. Persistent exposure to high γ-GTP levels was associated with higher risks of MI, stroke, CVD, and death than those without such exposure. The risks of MI, stroke, CVD, and mortality increased in a dose-dependent manner according to total cumulative γ-GTP (all P for trend <0.0001). Subjects younger than 65 years, with a body mass index <25 kg/m2, and without hypertension or fatty liver showed a stronger relationship between cumulative γ-GTP and the incidence of MI, CVD, and death. Conclusion Cumulative γ-GTP elevation is associated with CVD. γ-GTP could be more widely used as an early marker of CVD risk, especially in individuals without traditional CVD risk factors