A preliminary study of improving the MICP effects via the extractions from seashell nacre

In microbially induced calcium carbonate precipitation (MICP) process, it is the precipitated CaCO3 that cements loose sand particles together to improve their mechanical properties. Seashell nacre composed of CaCO3 is a natural product, which is worth researching for its great hardness, strength, and toughness. However, there is no study connecting this natural nacre mineralization with MICP. Therefore, a precedent herein is established to modify the MICP process via the water-soluble matrix (WSM) extracted from nacre, where WSM contributes to the great mechanical properties of nacre. Correspondingly, this study examines the effects of WSM with different concentrations on urease activity and strength as well as microstructure of bio-cemented sand samples. The experimental results show that a small number of WSM (50mg/L) can improve the average strength of bio-cemented sand samples 1.5 times. This is because 50mg/L WSM can significantly improve the urease activity of bacteria meanwhile increasing the Ca2+ utilization rate. Thus, more CaCO3 crystals are precipitated, and the higher UCS of bio-cemented sand samples is achieved. Moreover, the XRD results indicate that the precipitated CaCO3 is almost calcite, and only a little aragonite is detected when the concentration of WSM increases to 100mg/L. Additionally, the SEM images demonstrate that WSM involvement can affect the shapes and sizes of CaCO3 crystals. Overall, this work is an unprecedented exploration imitating nacre that hopefully paves way for future studies.

Examining Impacts of Acidic Bath Temperature on Nano-Synthesized Lead Selenide Thin Films for the Application of Solar Cells

The influence of bath temperature on nano-manufactured PbSe (lead selenide) films was successfully generated by utilizing CBD on the acid solution’s metal surface tool. Pb (NO3)2 was employed as a lead ion source as a precursor, while Na2O4Se was used as a selenide ion source. The XRD characterization revealed that the prepared samples are the property of crystalline structure (111), (101), (100), and (110) Miller indices. The scanning electron microscope indicated that the particles have a rock-like shape. There was a decrement of energy bandgap that is from 2.4 eV to 1.2 eV with increasing temperature 20°C–85°C. Thin films prepared at 85°C revealed the best polycrystal structure as well as homogeneously dispersed on the substrate at superior particle scales. The photoluminescence spectrophotometer witnessed that as the temperature of the solution bath increases from 20°C to 85°C, the average strength of PL emission of the film decreases. The maximum photoluminescence strength predominantly exists at high temperatures because of self-trapped exciton recombination, formed from O2 vacancy and particle size what we call defect centres, for the deposited thin films at 45°C and 85°C. Therefore, the finest solution temperature is 85°C.

Effect of Artificial Ageing on Adhesive Bonds from Heat Treated Spruce

The influence of artificial ageing on bonded heat-treated spruce lamellas was investigated. Heat-treated spruce lamellas with different degrees of thermal modification were bonded with PVAc and MUF and then exposed to 500 artificial weathering cycles, combined with rain, UV and IR radiation. The colour change of the exposed surface, weight change, delamination of the bonded joints and adhesive bond strength were measured. Artificial weathering caused cracking and delamination of the bonded joints and reduced the bond strength of both adhesives. The results show that delamination was higher for PVAc adhesive than MUF, but increased for both adhesives with the temperature of heat treatment of wood. The shear strength of bonds on the exposed side of the samples after the artificial weathering was lower than the average strength of the whole sample.

CORRELATIONS BETWEEN FIBER OUTPUT AND SOME ECONOMICALLY VALUABLE CHARACTERISTICS IN COTTON LINES IN DIFFERENT CULTIVATION REGIONS

Phenotypic correlations were determined between fiber yield and some economic traits in ten lines of medium-fiber cotton Gossypium hirsutum grown in three different regions of Uzbekistan. It is noted that there is a direct relationship of average strength between the fiber yield and the length of the growing season. KEYWORDS: cotton, phenotype, correlation, fiber yield, growing season length, fiber quality, productivity

Influence of the Addition of Silica Nanoparticles on the Compressive Strength of Cement Slurries under Elevated Temperature Condition

Drilling ever deeper, and thus in increasingly difficult conditions, is associated with restrictive requirements that must be met by cement slurries. This implies the need to use advanced, innovative measures that will significantly improve the performance parameters of the cement slurry and cement stone. Due to its unique properties, an admixture of nanosilica improves the properties of the cement stone and allows for appropriate zone insulation. The article presents the results of strength tests of cement stone samples with the addition of silica nanoparticles deposited in an environment of increased temperature of 90 °C. In all three cases of modification with an admixture of nanosilica (type 1, 2 and 3, concentration 0.5%, 1% and 5%), the cement stone shows an improvement in mechanical properties, which is manifested by an increase in compressive strength. The most homogeneous results of strength measurements are for cement slurries with an admixture of type 3 nanosilica (the highest average strength: 132–149% in relation to the base sample). They show the smallest stretch marks and deviations from the average. The highest average increase in strength is for the sample with the addition of 1% nanosilica (on average 124% in relation to the base sample). This amount causes the greatest increase in strength with no significant deterioration of rheological parameters.

The role of markers of endothelial dysfunction, oxidative and cellular stress in the prediction of myocardial infarction in comorbid patients with stable coronary heart disease

Aim. To study the role of markers of endothelial dysfunction, oxidative and cellular stress in the prediction of myocardial infarction (MI) in comorbid patients with stable coronary heart disease (CHD). Material and methods. The study involved 336 patients with a diagnosis of CHD. The presence of CHD was confirmed by diagnostic coronary angiography with the calculation of the Gensini index. All patients were divided into 2 groups: group 1288 patients without a history of MI, group 248 patients with a history of MI. All patients were assessed for the levels of oxidized modified proteins, high-sensitivity C-reactive protein (hs-CRP), homocysteine, heat shock protein (HSP70), and superoxide dismutase activity. Results. All patients were comparable in age. For other clinical and anthropometric characteristics, we saw significant differences (according to the MannWhitney criterion): patients with previous MI had higher BMI, waist circumference, and blood pressure. The correlation analysis revealed positive significant average strength relationships between past MI and the Gensini index, low-density lipoprotein level, total cholesterol level, homocysteine level, hs-CRP level, and the level of oxidized modified proteins; and negative significant average strength relationships between past MI and SOD activity level (r=-0.374, p=6.4 E-07) and HSP70 level (r=-0.563, p=2.6 E-15). The ROC analysis revealed that not all markers were significant in predicting the risk of MI. It is shown that the most expected characteristics were shown by the hs-СRP. However, further analysis of the predictive significance of the markers demonstrated that the addition of HSP70 to hs-CRP increases the predictive significance of hs-CRP in relation to the risk of developing MI. Conclusion. We have demonstrated that a strategy using a cumulative risk assessment consisting of 2 biomarkers (individually involved in inflammation and stress-induced cellular responses) can identify patients with an established diagnosis of CHD who have an increased risk of acute MI.

CPUE comparison of traditional crayfish fyke net rigged with knotted net and alternatively knotless net

In this study, it is aimed to compare the yield and strength of the crayfish fyke rigged with knotless net with 210d/12 rope thickness with those of the traditional net material rigged with 210d/6 knotted net which is widely used in Turkey in fishing crayfish (Pontastacus leptodactylus, Eschscholtz, 1823). The study was carried out on a monthly basis between June 2017 and May 2018. In the study, a total of 300 fyke nets, equipped with 150 classical and 150 alternative nets, were used. The caught crayfishes were measured and weighted according to the fyke net they were caught in. A total of 3509 crayfish were caught, 1465 of which were caught with alternative fyke net and 2044 with traditional fyke net. Average CPUE value ranged from 10.93 (g/fyke net/day) to 281.14 (g/fyke net/day) for per fishing operation. Average CPUE value of the traditional gear was found to be 98.34 (g/fyke net/day) , while that of the alternative gear was determined as 79.46 (g/fyke net/day), and no statistically significant difference was found between average CPUE values (p>0.05). Average strength value of the traditional fyke net was determined as (± SE) 10.43 ± 0.27 kg, while that value in 210d / 12 knotless net was identified as 14.50 ± 0.91 kg (p<0.05). Although it has high strength, since the CPUE value of the alternative fyke net is lower by 19.20% compared to the traditional gear, it is believed that its use in crayfish fishing will not be profitable.

Effect of pyrolytic carbon interphase on mechanical properties of mini T800-C/SiC composites

The effect of pyrolytic carbon (PyC) thickness on the tensile property of mini T800 carbon fiber reinforced SiC matrix composites (C/SiC) was studied. PyC interphase was prepared by chemical vapor infiltration (CVI) process using C3H6–Ar as gas source, the PyC thickness was adjusted from 0 to 400 nm, and then the SiC matrix was prepared by CVI process using methyltrichlorosilane (MTS)–H2–Ar as precursor and gas source. The results showed that the tensile strength of mini T800-C/SiC increased first and then decreased with the increase of the PyC thickness. When the thickness of PyC was 100 nm, the average strength reached the maximum value of 393 ± 70 MPa. The Weibull modulus increased from 2.0 to 8.06 with the increase of PyC thickness, and the larger the Weibull modulus, the smaller the dispersion, which indicated that the regulation of PyC thickness was conducive to improve tensile properties.

Kekuatan Genggaman Tangan pada Pasien Post Stroke

Stroke is a loss of brain function caused by the cessation of blood supply in part of the brain. Death of brain tissue due to stroke can cause muscle weakness in the affected limb such as fingers. This condition affects the ability to move and the quality of life of patients. Patients not only experience paralysis but also experience cognitive impairment, communication disorders, and visual field disorders or deficits in perception. Aims this study was to describe handgrip strength The average age of respondents was 60.5 years with the youngest age 41 years and 80 years of age. The average strength of the handgrip is 7.4 kg with the lowest strength is 1.3 kg and the highest is 18.6 kg. Obtained a relationship between age and muscle strength after stroke (p 0.023). The relationship between age and post-stroke muscle strength shows that the relationship between medium strength and negative patterning means that as you age, muscle strength decreases. So it is necessary to develop the Pattern of Activities and exercises for Post Stroke in Hospitals and the Community.

INCREASED LIFE EXPECTANCY BASED ON PHYSICAL FORMULAS

Life expectancy is due to the frequency of processes occurring in the body. The lower the frequency, the longer the lifespan. The frequency is influenced by the fraction of vacuum particles in a free, unbound state. Elementary particles are connected, grouped particles of vacuum. But in a free state, a large proportion of them affect the frequency of oscillations, increasing it, therefore, reducing the lifetime. The connection between a living organism and an inanimate body has been drawn. Dislocations are analogous to vacuum particles. Their low density and low fraction of vacuum particles describe the theoretical ultimate strength and lifetime. The increase in density and the formation of crystalline elementary particles cause the average lifetime and average strength, orders of magnitude smaller than the theoretical one. A further increase in the dislocation density causes cracks and ruptures, and partly chaotic formation — tumors, partly crystalline. Chaos and order are described by a complex unified field that causes tumors. This unified field is described by the hydrodynamic, acoustic, complex Reynolds number with a small imaginary part. But the formation of a small imaginary Reynolds number is an inevitable process with increasing time, as is the formation of tumors. But how to deal with them. It is necessary for the tumors to pass from a partially chaotic state to a crystalline one, forming elementary particles. This requires a periodic unified field with a wavelength equal to a constant period, which is formed by vacuum particles in elementary, crystalline particles. In addition, an imaginary magnetic field is required, which has a sign opposite to the Reynolds number. Just irradiating the tumor will not help, you need a certain wavelength and a certain sign of the imaginary magnetic