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"Diamonds Purchasing."
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Bionic design and test of polycrystalline diamond compact bit for hard rock drilling in coal mine
For hard rock drilling in coal mine, the drilling efficiency and service life of polycrystalline diamond compact bit are very low. To overcome these shortcomings, the bionic technology is applied to the design and processing of polycrystalline diamond compact bit. The bit body and polycrystalline diamond compact cutter are designed as bionic structures, and the test of the bionic polycrystalline diamond compact bit is carried out. Test results show that, when drilling in fine sandstone with hardness greater than 9, the performance of the bionic polycrystalline diamond compact bit is significantly improved. Comparing with the Φ113-mm concave polycrystalline diamond compact bit, the service life and drilling efficiency of the A-type bionic polycrystalline diamond compact bit increase by 54% and 230%, respectively, the service life and drilling efficiency of the B-type bionic polycrystalline diamond compact bit increase by 345% and 204%, respectively, which show that the bionic design of polycrystalline diamond compact bit can provide a new research idea for hard rock drilling in coal mine. Also the test results indicate that, when processing the bionic polycrystalline diamond compact cutter, the linear cutting process will cause thermal damage to the diamond layer of polycrystalline diamond compact cutter, while the cold grinding process shows higher comprehensive performance, therefore the one-time synthesis of bionic polycrystalline diamond compact cutter is the future research direction.
Journal Article
Design and test of a self-adaptive bionic polycrystalline diamond compact bit inspired by cat claw
Cats protract claws while hunting or pawing on the ground and retract to muscles when relaxing. Inspired by this behavior, and in order to solve the problem of short service life and low comprehensive drilling efficiency of polycrystalline diamond compact bits which results from its poor adaptability to soft-hard interbedded strata, a self-adaptive bionic polycrystalline diamond compact bit was designed, which can use the elastic element to adjust its back-rake angle according to the formation hardness to improve the adaptability of polycrystalline diamond compact bits. Theoretical analysis and drilling test results show that the self-adaptive bionic polycrystalline diamond compact bit has a strong adaptability to soft-hard interbedded rock strata. When drilling in soft rock, the back-rake angle is small and the rate of penetration is high; when drilling in hard rock, the angle becomes larger to reduce the abnormal damage of cutters. Thus, it can improve the integrated drilling efficiency and service life of polycrystalline diamond compact bits. In the whole drilling test, the average penetration rate of the self-adaptive bionic polycrystalline diamond compact bit increases by 10%–13% over conventional polycrystalline diamond compact bits with the same dimension and material.
Journal Article
Federating diamond OA in Europe and beyond: the European Diamond Capacity Hub (EDCH)
This case study presents the context, governance and operations of the European Diamond Capacity Hub (EDCH) launched in January 2025. The EDCH will coordinate diamond open access (OA) capacity centres in Europe and consolidate and align the diamond OA organizations that provide services and tools to diamond OA outputs in Europe. In this way, it will provide the backbone for a scholarly communication infrastructure that is owned and operated by the academic community without charges for authors and readers.
Journal Article
Microstructure and performance of monolayer brazed grinding wheel with polycrystalline diamond grains
Monolayer brazed grinding wheels were prepared using polycrystalline diamond grains, Ni-Cr-B-Si brazing alloy, and commercial Q235A steel with the brazing temperature 1000 °C and the holding time 5 min. The microstructure and element distribution of joint interface was studied through scanning electron microscope and energy dispersive X-ray spectroscope, respectively. Grinding performance of wheels was evaluated during grinding alumina specimen. The fracture of polycrystalline diamond grains with the embedding depth of 50 and 70 % was studied quantitatively. The results show that good joint interface was formed among polycrystalline diamond grains, Ni-Cr-B-Si brazing alloy, and Q235A steel through element diffusion and chemical reaction during brazing. Chemical resultants Cr
3
C
2
and Cr
7
C
3
formed within joint interface between polycrystalline diamond grain and Ni-Cr-B-Si brazing alloy; meanwhile, the growth of Cr
3
C
2
has an orientation relationship with element arrangement of diamond surface. Compared with single crystal diamond grinding wheel, the polycrystalline diamond grinding wheel has exhibited evident advantages according to the grinding force and force ration (tangential grinding force F
t
/ normal grinding force F
n
). The F
n
and F
t
is 21.69 and 7.23 N with the expositing high of 50 % and 5.16 and 1.72 N with the expositing high of 70 % respectively, when polycrystalline diamond grain fracture takes place. The failure mechanism of brazed polycrystalline diamond grains grinding wheel is diamond fracture.
Journal Article
I-T - Tax authorities are not entitled to tax entire transaction, but only income component of disputed transaction, to prevent possibility of revenue leakage: HC
HC ++ this Court in case of Pankaj K. Choudhary, while dismissing the Tax Appeal No.617 of 2022 has held that \"...It is settled law that under Income-tax, the tax authorities are not entitled to tax the entire transaction, but only the income component of the disputed transaction, to prevent the possibility of revenue leakage. [...]considering overall facts and circumstances of the present case, we are of the view that disallowances @ 6% of impugned purchases / disputed purchases would be sufficient to meet the possibility of revenue leakage...\" Heard learned Senior Standing Counsel Mr. Karan G. Sanghani for the appellant. 2. Since issues involved in both these Tax appeals are identical, they have been heard together and would be disposed of by this common order. 3. At the outset, learned advocate Mr.Karan Sanghani for the Appellant-Revenue submitted that the Tribunal has relied upon the Judgment of the Co-ordinate Bench of this Court (Coram: Hon'ble Mr.Justice N.V.Anjaria and Hon'ble Mr.Justice Niral R. Mehta) in case of Principal Commissioner of Income Tax Versus Pankaj K. Choudhary dated 07.03.2023 rendered in Tax Appeal No.617 of 2022 for partly allowing the appeal of the Revenue wherein it was held that in respect of bogus purchases, the addition at the rate of 6% of bogus purchases is fair and reasonable. 14. The requirements of section 147 r.w.s. 148 have clearly been met; and the reopening is held justified and legal. [...]we dismiss the ground raised by the assessee challenging the validity of reassessment. 19.
Trade Publication Article
Towards an internationalized sustainable industrial competitiveness model
Purpose - Within the context of globalization, industrial competitiveness has played a decisive role in determining a country's status in the world. Porter's Diamond Model is the most popular competitiveness theory currently available for explaining the achievement of a country's industrial and firm's competitive advantage. There has been considerable discourse in relation to Porter's Model and the purpose of this paper is to critique and refine Porter's Diamond Model and consider the theme of sustainable development towards the development of a new conceptual model, merging theories and concepts from internationalization, sustainable development and industry competitiveness.Design methodology approach - Critical analysis of industrial competitiveness literature to explore the discourse on Porter's Model and identify challenges which are then informed by a consideration of internationalization and sustainable development literature.Findings - The Porter's Diamond Model is re-formed as the Internationalized Sustainable Industrial Competitiveness Model (ISIC Model) to meet the trends of internationalization and sustainable development.Originality value - The sustainable development concept is explicitly connected with competitiveness.
Journal Article