Study of integral and differential strength and deformation characteristics of centrifuged and vibrating centrifuged concrete on activated Portland cement

In this work, the study of integral and differential strength and deformation characteristics of centrifuged and vibrating centrifuged concrete on activated Portland cement was carried out. Mechanical activation of cement was carried out using a specialized grinding unit. Manufacturing of centrifuged and vibrating centrifuged samples was carried out on an experimental laboratory centrifuge. All samples were made of concrete of the same composition. The optimum values of technological parameters of centrifugation and vibrating centrifugation are given. The scheme of obtaining small-size specimens from a common annular section to determine the strength and strain characteristics was developed. According to the results of the study it was found that the improvement of integral and differential strength and strain characteristics when using activated Portland cement is observed for both centrifuged and vibrating centrifuged specimens. However, the samples made by vibrating centrifugation technology have better strength and strain characteristics than the samples made by centrifugation. According to the results of the study, it was found that the activation of Portland cement at its rational values is the best way to enhance variatropy.

Investigation of the integral strength and deformation characteristics of centrifuged and vibrocentrifuged concretes on activated Portland cement

In this work, a study of the integral strength and deformation characteristics of centrifuged and vibrocentrifuged concretes on activated Portland cement is carried out. Mechanical activation of cement was carried out using a specialized grinding unit. The manufacture of centrifuged and vibrocentrifuged samples was carried out on an experimental laboratory centrifuge. All samples were made from concrete of the same composition. In total, four basic samples of annular cross-section were manufactured and tested with the following dimensions: outer diameter D = 450 mm; inner hole diameter d = 150 mm; total height H = 1200 mm. The optimal values ​​of technological parameters of centrifugation and vibrocentrifugation are given. A scheme has been developed for obtaining small-sized samples from a common annular section to determine the strength and deformation characteristics. According to the results of the study, it was found that an improvement in the values ​​of integral strength and deformation characteristics when using activated Portland cement is observed in both centrifuged and vibrocentrifuged samples. It was found that samples made by vibrocentrifugation technology have the best strength and deformation characteristics than samples made by centrifugation. The conclusion is made about the technology of vibrocentrifugation as the most preferable for the manufacture of reinforced concrete products of annular section.

Investigation of differential strength and deformation characteristics of centrifuged and vibrocentrifuged concretes on activated Portland cement

In this work, a study of the strength and deformation characteristics of the variatropic layers of centrifuged and vibrocentrifuged concretes on activated Portland cement was carried out. Mechanical activation of cement was carried out using a specialized grinding unit - a planetary ball mill "Aktivator-4M". The optimal mode of grinding Portland cement is proposed. For the manufacture of centrifuged and vibrocentrifuged samples, an experimental laboratory centrifuge TsSRL-1 with a DC electric motor with thyristor power supplies was used, and the form vibrations were carried out due to additional dowels (protrusions) put on the shafts. All samples were made from concrete of the same composition. In total, four basic samples of annular cross-section were manufactured and tested with the following dimensions: outer diameter D = 450 mm; inner hole diameter d = 150 mm; total height H = 1200 mm. The optimal values ​​of technological parameters of centrifugation and vibrocentrifugation are given. A scheme is proposed for obtaining small-sized samples to determine the strength and deformative characteristics of various layers of a sample by cutting them out of a common annular section. According to the results of the study, it was found that the activation of Portland cement at its rational values ​​is the optimal way to enhance variatropia.

Theoretical and Practical Aspects of the Formation of the Variational Structure of Centrifuged Products from Heavy Concrete

Viability of further research of variatropy is justified, as well as its extended use with the purpose of increasing quality of ferroconcrete building constructions. Raw components and equipment used for manufacturing of centrifuged products and variatropic objects are described. Laboratory centrifuge equipped with a direct current engine and thyristor units has been developed and used. Method of applying pressure to a unit mass during centrifuging has been studied. It has been identified that in order for mix particles rising to their most superior position to stick to the mold walls, it is necessary that gravitational force of mg particle and centrifugal force are equal. Effect of hydrodynamic pressure on particles constituting concrete mix has been studied using several formulas and provisions. It has been revealed that centrifugal molding may be used to seal low-viscosity plastic mixes; however, its use causes disintegration of concrete mix. In order to slow down this process, it is necessary to increase viscosity of the entire system and restrict the upper limit of aggregate fineness.

HSLC_FUGE: HIGH SPEED AND LOW COST LABORATORY CENTRIFUGE FOR GENOMIC DNA PURIFICATION

A laboratory centrifuge is a piece of laboratory equipment, driven by a motor, which spins liquid samples at high speed. There are various types of centrifuges, depending on the size and the sample capacity. Like all other centrifuges, laboratory centrifuges work by the sedimentation principle, where the centripetal acceleration is used to separate substances of greater and lesser density. The information for synthesizing the molecules that allow organisms to survive and replicate is encoded in genomic DNA. Extracted and purified genomic DNA is very important for the analysis of single nucleotide polymorphisms (SNPs), disease states, and for many other multiplex and real-time PCR applications. The aim of this work is to design a genomic DNA extraction system that satisfies downstream application needs necessary for the successful completion of experiments and able to isolate a purified genomic DNA from many sources from bacteria to humans and also is able to encompass tissues from blood to muscle and from leaf to seed. Results revealed that the proposed system works with high efficiency and spins at up to 12,000 RPM to facilitate separation of the different phases of the extraction.

Experimental Evaluation of Separation Methods for a Riser Dilution Approach to Dual Density Drilling

A dual gradient, deepwater drilling system based on dilution of riser mud requires economically separating the riser mud into a low density dilution fluid and a higher density drilling fluid. This study investigated the practicality of accomplishing this separation using hydrocyclones and centrifuges and examined the possible benefits and efficiency of each. The separation experiments were conducted using a laboratory centrifuge and 2 in. hydrocyclones. The laboratory centrifuge was able to separate the riser mud into near ideal densities for dilution and drilling fluid. However, the dense slurry retained in the centrifuge had lower electrical stability than the feed stream. The hydrocyclones achieved much less contrast in density between the low and high density discharges, but their use consistently resulted in a beneficial increase in the stability of the mud emulsion in all of the flow streams and gave more desirable rheological properties. A qualitative comparison indicates that the hydrocyclone separation system may offer a feasible and desirable alternative to a centrifuge separation system.

Experimental Evaluation of Separation Methods for a Riser Dilution Approach to Dual Density Drilling

A dual gradient, deepwater drilling system based on dilution of riser mud requires economically separating the riser mud into a low density dilution fluid and a higher density drilling fluid. This study investigated the practicality of accomplishing this separation using hydrocyclones and centrifuges and examined the possible benefits and efficiency of each. The separation experiments were conducted using a laboratory centrifuge and 2 inch hydrocyclones. The laboratory centrifuge was able to separate the riser mud into near ideal densities for dilution and drilling fluid. However, the dense slurry retained in the centrifuge had lower emulsion stability than the feed stream. The hydrocyclones achieved much less contrast in density between the low and high density discharges, but consistently resulted in a beneficial increase in the stability of the mud emulsion in all of the flow streams and had more desirable rheological properties. A qualitative comparison indicates that the hydrocyclone separation system may offer a feasible and desirable alternative to centrifuge separation system.