Time-Dependent Shrinkage Model for Recycled Fine Aggregate Thermal Insulation Concrete

In this study, the shrinkage performance of recycled aggregate thermal insulation concrete (RATIC) with added glazed hollow beads (GHB) was investigated and a time-dependent shrinkage model was proposed. Two types of recycled fine aggregate (RFA) were used to replace natural fine aggregate in RATIC: RFA from waste concrete (RFA1) and waste clay brick (RFA2). Besides, the mechanical properties and thermal insulation performance of RATIC were also studied. Results showed that the pozzolanic reaction caused by RFA2 effectively improved the mechanical properties of RATIC; 75% was the optimal replacement ratio of RATIC prepared by RFA2. Added RFA decreased the thermal conductivity of thermal insulation concrete (TIC). The total shrinkage strain of RATIC increased with the increase of the replacement ratio of RFA. The 150d total shrinkage of RATIC prepared by RFA1 was 1.46 times that of TIC and the 150d total shrinkage of RATIC prepared by RFA2 was 1.23 times. The addition of GHBs led to the increase of early total shrinkage strain of concrete. Under the combined action of the higher elastic modulus of RFA2 and the pozzolanic components contained in RFA2, the total shrinkage strain of RATIC prepared by RFA2 with the same replacement ratio was smaller than that of RATIC prepared by RFA1. For example, the final total shrinkage strain of RATIC prepared by RFA2 at 100% replacement ratio was about 18.6% less than that of RATIC prepared by RFA1. A time-dependent shrinkage model considering the influence of the elastic modulus of RFA and the addition of GHB on the total shrinkage of RATIC was proposed and validated by the experimental results.

OK-432 treatment of pediatric patients with recurrent thyroglossal duct cyst after surgery

<b>Introduction:</b> Recurrent thyroglossal duct cyst after surgery is not a rare condition and first-line treatment has not been established yet.<br/><br/> <b>Aim:</b> Evaluation of outcomes and complications of OK-432 treatment in patients with recurrent thyroglossal duct cyst after surgery. <br/><br/> <b>Material and methods:</b> This study is designed as a case series with planned data collection at Tohoku Medical and Pharmaceutical University and Fukase Clinic. Five patients with recurrent thyroglossal duct cyst after surgery received this therapy between January 2014 and February 2020 on an outpatient basis, without hospitalization. OK-432 solution was injected into the lesion using an 18- or 27-gauge needle, depending on the location and size of the lesion, as well as on possible complications.<br/> <br/> <b>Results:</b> Lesions showed marked reduction or total shrinkage in all patients, with no local scarring or deformity at the injection site. Side effects manifested as local pain at the site of injection and fever (37.5–38.5°C) observed in three patients, but the symptoms resolved within a few days.<br/> <br/> <b>Conclusions:</b> Since OK-432 therapy is simple, easy, safe and effective, it can be used as an alternative to surgery in the treatment of recurrent thyroglossal duct cyst after surgery.

Using Long Term Integrated Average Analysis Machine Learning Prediction for Spreadable Diseases

The spread of Spreadable Disease in the entire world has put the humankind in danger. The assets of probably the biggest economies are worried because of the enormous infectivity and contagiousness of this illness. The ability of ML models to conjecture the quantity of forthcoming patients influenced by Spreadable Disease which is by and by considered as a likely danger to humanity. Specifically, four standard estimating models linear regression (LR),least total shrinkage and determination administrator (LASSO) Support vector Machine (SVM) have been utilized in this examination to figure the undermining components of Spreadable Disease. Three sorts of expectations are made by every one of the models, for example, the quantity of recently tainted cases, the quantity of passing, and the quantity of recuperations But in the can't foresee the precise outcome for the patients. To defeat the issue, Proposed strategy utilizing the exponential smoothing (ES) anticipate the quantity of Spreadable Disease cases in next 30 days ahead and impact of preventive estimates like social seclusion and lockdown on the spread of Spreadable Disease

Volume Deformation of Steam-Cured Concrete with Slag during and after Steam Curing

In order to better predict the development of shrinkage deformation of steam-cured concrete mixed with slag, a deformation-temperature-humidity integrated model test, a hydration heat test, and an elastic modulus test were performed. The effects of the steam-curing process and the content of slag on shrinkage deformation, hydration degree and elastic modulus of concrete were studied. The results indicate that during the steam-curing process, the concrete has an “expansion-shrinkage” pattern. After the steam curing, the deformation of concrete is dominated by drying shrinkage. After the addition of slag, the shrinkage deformation of steam-cured concrete is increased. The autogenous shrinkage increases by 0.5–12%, and the total shrinkage increases by 1.5–8% at 60 days. At the same time, slag reduces the hydration degree of steam-cured concrete and modulus of elasticity. A prediction model for the hydration degree of steam-cured concrete is established, which can be used to calculate the degree of hydration at any curing age. Based on the capillary tension generated by the capillary pores in concrete, an integrated model of autogenous shrinkage and total shrinkage is established with the relative humidity directly related to the water loss in the concrete as the driving parameter. Whether the shrinkage deformation is caused by hydration reaction or the external environment, this model can better predict the shrinkage deformation of steam-cured concrete.

INFLUENCE OF METAKAOLIN ON PROPERTIES OF CONCRETE MODIFIED WITH POLYCARBOXYLATE ADMIXTURE FOR RIGID PAVEMENT REPAIR

The effect of partial cement replacement with high-activity metakaolin on the strength, frost resistance, shrinkage and abrasion resistance of concrete modified with polycarboxylate admixture MasterGlenium SKY 608. Portland cement CEM II/A-S 42.5 (ПЦ II/А-Ш-500) with partial metakaolin replacement 15 kg (3.75 %) and 30 kg (7.5 %) was used for concrete preparation. The amount of superplasticizer in all studied compositions was 1.2% of cement weight. Slump of concrete mixtures was 6…7 cm. It was found that with increasing amount of metakaolin W/C ratio of mixtures increased slightly. The early compressive and flexural strength (at the age of 2 days) of the composition without metakaolin was higher than similar indicators with partial cement replacement with the active mineral admixture. It is worth noting the positive effect of increasing the metakaolin amount on early strength, because the composition with 30 kg metakaolin had strengths higher at 2 days of in difference to the composition with 15 kg metakaolin. It is necessary to note high frost resistance of all obtained concretes. Its grade of frost resistance reached F200 (evaluated according to the method for road concrete), which is equivalent to the grade F600 for structural concrete. Abrasion resistance was in the low range (0.30-0.31 g/cm2), total shrinkage does not exceed 0.28 mm/m, which in combination with high frost resistance has a positive effect on the durability of concrete mixtures for rigid pavements repair.

Features of Use of Rapid Prototyping Technology in the Manufacture of Wax Models of GTE Turbine Blades

The paper presents the main results related to the peculiarities of using 3D printing technology and methods of rapid prototyping in the manufacture of wax models of blades of a GTE turbine. The main design solutions that must be used in the design of a blade blank are presented in detail: the total shrinkage coefficient, equidistant rolling of the airfoil profile, allowance along tract surfaces, radial fillets, and a number of others. The results of control of geometric dimensions of the turbine blade blanks at the corresponding stages of the technological process showed deviations from the nominal value within the tolerance range for the executable dimensions, and the statistical information from the measurement of an experimental batch of wax models of blade blanks showed stability of the silicone tooling and ability to manufacture a series of wax models of the blades in the amount of 100 pieces when using one mold.

Bridge Decks: Mitigation of Cracking and Increased Durability—Phase III

Early-age cracking in concrete decks significantly reduces the service life of bridges. This report discusses the application of various concrete mixtures that include potential early mitigation ingredients. Large-scale (7 ft × 10 ft) experimental bridge prototypes with similar restraint conditions found in actual bridges were poured with different concrete mixtures to investigate mitigation techniques. Portland cement (control), expansive Type K cement, internally cured lightweight aggregate (LWA), shrinkage-reducing admixture (SRA), and gypsum mineral were investigated as mitigating ingredients. Seven concrete mixtures were prepared by using individual ingredients as well as a combination of different ingredients. The idea behind combining different mitigating techniques was to accumulate the combined benefit from individual mitigating materials. The combined Type K cement and LWA mixture showed higher concrete expansion compared with mixtures containing Portland cement, Type K cement, LWA, and SRA in the large-scale experimental deck. Extra water provided by LWA significantly enhanced the performance of Type K cement’s initial expansion as well as caused larger total shrinkage over the drying period. A combination of Type K cement and gypsum mineral showed insignificantly higher expansion compared with the individual Type K mixture. Overall, the experimental deck containing SRA showed the least total shrinkage compared with other mixtures. Finite-element modeling was performed to evaluate and predict concrete stress-strain behavior due to shrinkage in typical bridges. A parametric study using finite-element analysis was conducted by altering the structure of the experimental deck. More restraint from internal reinforcement, less girder spacing, larger girder flange width, and more restrictive support conditions increased the concrete tensile stress and led to potential cracking in the concrete deck.

Experimental Study on Marble and Brick Powders as Partial Replacement of Cement in Self-compacting Mortar

Aims: To produce a low environment impact concrete by recycling waste brick and waste marble. Background: Marble and brick wastes are produced as a byproduct during manufacturing or cutting processes. These materials could be used as a substitution to cement in mortar and concrete to reduce its environmental impact. Objective: To study the performance of self-compacting mortar with marbles and brick powders at the fresh and hardened states. Results: It is an experimental investigation where two Blaine finenesses of marble and brick powders were used. Rheological, mechanical and physical properties of the new composites were studied. Results: The results show that for optimal workability and compressive strength of SCM, the maximum percent of substitution must not exceed 5% for brick powder, whereas for marble powder it can reach up to 20% according to the fineness of powder. The incorporation of brick and marble powders separately decreases the shrinkage of SCM and the combination of both powders has a positive effect on its sorptivity coefficient and total shrinkage. Conclusion: Maximum 5% and 20% of brick and marble powder respectively are recommended for optimal properties of self-compacting mortar.

The human cerebellum has almost 80% of the surface area of the neocortex

The surface of the human cerebellar cortex is much more tightly folded than the cerebral cortex. It was computationally reconstructed for the first time to the level of all individual folia from multicontrast high-resolution postmortem MRI scans. Its total shrinkage-corrected surface area (1,590 cm2) was larger than expected or previously reported, equal to 78% of the total surface area of the human neocortex. The unfolded and flattened surface comprised a narrow strip 10 cm wide but almost 1 m long. By applying the same methods to the neocortex and cerebellum of the macaque monkey, we found that its cerebellum was relatively much smaller, approximately 33% of the total surface area of its neocortex. This suggests a prominent role for the cerebellum in the evolution of distinctively human behaviors and cognition.