Wyniki wyszukiwania - BazTech

1

An investigation into the effect of rockmass properties on mean fragmentation

Chandrahas Sri, Choudhary Bhanwar Singh, Prasad N. S. R. Krishna, Musunuri Venkataramayya, Rao K. K.

Archives of Mining Sciences

|

2021

|

Vol. 66, no. 4

561--578

EN

Desired rock fragmentation is the need of the hour, which influences the entire mining cycle. Thus, most engineering segments pay attention to rock fragmentation and neglect by-products like ground vibration and fly rock. Structural and mechanical properties of rock mass like joint spacing, joint angle, and compressive strength of rock pose a puzzling impact on both fragmentation and ground vibration. About 80% of explosive energy that gets wasted in producing ill effects can be positively optimised, with a new set of blast design parameters upon identifying the behaviour of rock mass properties. In this connection, this research aims to investigate the influence of joint spacing, joint angle, and compressive strength of rock on fragmentation and induced ground vibration. To accomplish this task, research was carried out at an opencast coal mine. It was discovered from this research that compressive strength, joint spacing, and joint angle have a significant effect on the mean fragmentation size (MFS) and peak particle velocity (PPV). With the increase in compressive strength, MFS explicit both increase and decrease trends whilst PPV increased with a specific increase in compressive strength of the rock. An increase in joint spacing triggers both increase and decrease trends in both MFS and PPV. While there is an increase in joint angle, MFS and PPV decrease.

2

Relationship between the mineral content of human trabecular bone and selected parameters determined from fatigue test at stepwise-increasing amplitude

Mazurkiewicz A. J., Topoliński T.

Acta of Bioengineering and Biomechanics

|

2017

|

Vol. 19, no. 3

19--26

EN

Purpose: The study aimed to investigate a relationship between the mineral content of the human trabecular bone and parameters determined from compression fatigue tests at stepwiseincreasing amplitude. Methods: Mineral content of the trabecular bone was estimated as ash density and bone mineral density values. The relationship between the ash density, bone mineral density and factors obtained from fatigue test: fatigue life, cumulative elastic energy and cumulative energy of dissipation was determined. Results: The results from the measurements of ash density and bone mineral density show good correlation with the fatigue test results. The relationship was estimated based on the correlation coefficient R within 0.74-0.79 for the particular pairs of factors. Conclusions: The study shows that the ash density and the bone mineral density are good predictors to estimate the fatigue life of trabecular bone. The study also validates the applicability of the tests at stepwise-increasing amplitude in determining the mechanical properties of trabecular bone.

3

The structure of the strength of riveted joints determined in the lap joint tensile shear test

Mucha J., Witkowski W.

Acta Mechanica et Automatica

|

2015

|

Vol. 9, no. 1

44--49

EN

The article presents the analysis of the structure of the load capacity of riveted joints. For the four joining systems the lap joint specimens were made and tested in the shearing test. The joints were prepared for the three combinations of the DC01 steel and EN AW- 5754 aluminium alloy sheets with the thickness of 2mm. On the basis of the obtained load-elongation diagram tensile shear test curves, the basic parameters defined in the ISO/DIS 12996 standard were determined. In the case of the conventional riveted joints the maximum load capacity of the joint is determined by the strength of the fastener. For the joints with aluminium-steel blind rivet , the load capacity of the joint was on the strength limit of the rivet tubular part and on the strength limit of the sheet material. The strength of the SSPR joint is determined by the mechanical properties of the material of the joined sheets. From all sheets and rivet specimens arrangements the highest load capacity of the joint was obtained for the DC01 sheet material joints, and the lowest load capacity of the joint was obtained for the EN AW-5754 sheet material joints.

4

Ocena jakości wysokogatunkowego koksu wielkopiecowego w skali zintegrowanego testu reakcyjności i wytrzymałości NSC

Mianowski A., Radko T., Koszorek A.

Przemysł Chemiczny

|

2009

|

T. 88, nr 6

692-698