A Discussion on Removal Mechanisms in Grinding Polycrystalline Diamond

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Florestan Schindler ◽  
Richard Brocker ◽  
Fritz Klocke ◽  
Patrick Mattfeld
Keyword(s):  
Material Removal ◽  
Polycrystalline Diamond ◽  
Material Removal Mechanism ◽  
Mesoscopic Scale ◽  
Tool Manufacture ◽  
Brittle Behavior ◽  
Process Characteristics ◽  
Chemical Effects ◽  
Removal Mechanisms ◽  
First Time

Polycrystalline diamond (PCD) grinding takes an important role in the field of tool manufacture. Regardless, there is still lack of process knowledge about the occurring material removal mechanisms in PCD grinding. In order to get a better understanding of the process characteristics, the surface integrity zone of PCD inserts has been analyzed in detail after grinding for the first time. The drawn conclusion questions solely ductile or brittle behavior as removal mechanisms. Both thermal and mechanical process loads during the grinding process lead to thermophysical and chemical effects on a micro- and mesoscopic-scale and might thus have a significant impact on the material removal mechanism.

Submarine volcanic activity and giant amygdale formation along the Panama island arc as a precursor to 6000-year-old agate exploitation on Pedro González Island

2021 ◽  
pp. 1-16
Author(s):  
Stewart D Redwood ◽  
David M Buchs ◽  
David Edward Cavell
Keyword(s):  
Volcanic Activity ◽  
Bimodal Distribution ◽  
Island Arc ◽  
Early Miocene ◽  
Tool Manufacture ◽  
Marine Deposits ◽  
Large Size ◽  
Hydrothermal Processes ◽  
Field Evidence ◽  
Geochemical Study

Abstract An extensive deposit of agate occurs in Pedro González Island in the Gulf of Panama. Previous archaeological research showed that the agate was exploited between 6200 and 5600 cal BP to make stone tools found at the oldest known Preceramic human settlement in the Pearl Island archipelago. We constrain here the origin and geological context of the agate through a geological and geochemical study of the island. We show that it includes primary volcanic breccias, lavas, and tuffaceous marine deposits with sedimentary conglomerates and debris flow deposits, which we define as the Pedro González Formation. This formation records submarine to subaerial volcanic activity along an island arc during the Oligo-Miocene, confirming previous regional models that favour progressive emergence of the isthmus in the early Miocene. The igneous rocks have an extreme tholeiitic character that is interpreted to reflect magmatic cessation in eastern Panama during the early Miocene. The agate is hosted in andesitic lavas in unusually large amygdales up to 20–40 cm in diameter, as well as small amygdales (0.1–1.0 cm) in a bimodal distribution, and in veins. The large size of the agates made them suitable for tool manufacture. Field evidence suggests that the formation of large amygdales resulted from subaqueous lava–sediment interaction, in which water released from unconsolidated tuffaceous deposits at the base of lava flows rose through the lavas, coalesced, and accumulated below the chilled lava top, with subsequent hydrothermal mineralization. These amygdales could therefore be regarded as an unusual result of combined peperitic and hydrothermal processes.

New Caledonian crows show behavioural flexibility when manufacturing their tools

Behaviour ◽  
2017 ◽  
Vol 154 (1) ◽  
pp. 65-91 ◽  
Author(s):  
Brenna Knaebe ◽  
Alex H. Taylor ◽  
Douglas M. Elliffe ◽  
Russell D. Gray
Keyword(s):  
Behavioural Flexibility ◽  
Tool Manufacture ◽  
In The Wild ◽  
New Caledonian Crows ◽  
Do So

New Caledonian crows have demonstrated flexible behaviour when using tools and solving novel problems. However, we do not know whether this flexibility extends to tool manufacture. Here, we show that these crows respond to different tool-using problems by altering the length of the tools that they manufacture; on average, crows made shorter tools for tasks requiring short tools and longer tools for tasks requiring long tools. They continued to do so when they could not simultaneously see the tool-manufacturing material and the apparatus requiring the use of a tool. Despite altering the length of their tools, the crows frequently did not make tools short or long enough to reliably extract the bait, though this may have been due to shortcomings in the task presented to them. Our results demonstrate that these crows have a degree of behavioural flexibility when making tools, which may be used in the wild during foraging.

scholarly journals STRATEGIC OVERVIEW OF FINANCIAL SUPPORT FOR THE DEVELOPMENT OF SMALL INNOVATIVE ENTERPRISES IN UKRAINE

2019 ◽  
pp. 53-64
Author(s):  
Danylo VANKOVYCH ◽  
Myroslav KULCHYTSKYJ
Keyword(s):  
Small Businesses ◽  
Financial Support ◽  
Essential Element ◽  
Main Tool ◽  
Innovation Activity ◽  
Aviation Industry ◽  
High Tech ◽  
Essential Property ◽  
Industrial Complex ◽  
Tool Manufacture

Introduction. Small innovative businesses play an important role in the economy of developed countries and are an essential element of the innovation process. Small enterprises are the most flexible, dynamic and widespread form of enterprises. Ukraine’s aspiration to European integration necessitates the introduction of an innovative model of development, one of the components of which is the development of a domestic innovation enterprise, which prompts to seek new approaches to the implementation of scientific, technical and innovative potential of the country’s economy. The purpose of the article is to find out the features and problems of financial support for the development of small innovative enterprises in Ukraine and to substantiate directions for its improvement. Results. According to the data of the State Statistics Service of Ukraine, innovation activity in Ukraine in 2018 was carried out only by every eleventh enterprise. The share of enterprises that introduced innovations in 2017 amounted to 16.2%, and those engaged in innovations 14.3%, respectively. At the same time, the share of innovative products in the total industrial volume was, according to the results of 2017, only 0.7%. In Ukraine, as of January 1, 2018, in the total number of enterprises (338256 units), the share of small business entities amounted to 95.5%. This testifies to the dependence of the level of development of the Ukrainian economy on their innovative activity. Among the range of obstacles to the successful functioning of innovative entrepreneurship, the problem of low efficiency of functioning of the financial mechanism of ensuring their development is the most urgent. Particular attention should be paid to the use of national competitive advantages, avant-garde industries, high-tech industries, such as space technology, aviation industry, biotechnology, tool manufacture, defense and industrial complex. Innovation demand in Ukraine should become not only an economic category but also an essential property of a person’s character. Conclusions. The development of innovative entrepreneurship is not carried out quickly and purposefully. Its potential, as the main tool for commercializing scientific ideas, is practically not implemented in Ukraine. Before small innovative enterprises, there are many barriers and obstacles that prevent them from working effectively. Thus, in order to provide effective financial support for the development of small innovative entrepreneurship, it is necessary, first of all, to improve the financial and tax policy of supporting small businesses, as well as to increase the efficiency of the use of established institutions of market infrastructure for supporting small businesses. The details of the mechanisms for implementing these measures should be the subject of further research, the results of which will be highlighted in the following publications.

scholarly journals The First Acheulian Quarry in India: Stone Tool Manufacture, Biface Morphology, and Behaviors

1999 ◽  
Vol 55 (1) ◽  
pp. 39-70 ◽  
Author(s):  
Michael Petraglia ◽  
Philip LaPorta ◽  
K. Paddayya
Keyword(s):  
Stone Tool ◽  
Tool Manufacture ◽  
And Behaviors

Levallois

2020 ◽  
Author(s):  
Michael Chazan
Keyword(s):  
Early Modern ◽  
Stone Tools ◽  
Stone Tool ◽  
General Level ◽  
Significant Component ◽  
Tool Manufacture ◽  
Core Technology ◽  
Artifact Analysis ◽  
Definition Of ◽  
The 19Th Century

Levallois refers to a way of making stone tools that is a significant component of the technological adaptations of both Neanderthals and early modern humans. Although distinctive Levallois artifacts were identified already in the 19th century, a consensus on the definition of the Levallois and clear criteria for distinguishing Levallois from non-Levallois artifacts remain elusive. At a general level, Levallois is one variant on prepared core technology. In a prepared core approach to stone tool manufacture, the worked material (the core) is configured and maintained to allow for the production of detached pieces (flakes) whose morphology is constrained by the production process. The difficulty for archaeologists is that Levallois refers to a particular process of manufacture rather than a discrete finality. The study of Levallois exposes limitations of typological approaches to artifact analysis and forces a consideration of the challenges in creating a solid empirical basis for characterizing technological processes.

The Economic Geography of Chert Lithic Production in the Southern Maya Lowlands: A Comparative Examination of Early-Stage Reduction Debris

2009 ◽  
Vol 20 (1) ◽  
pp. 91-119 ◽  
Author(s):  
C. Scott Speal
Keyword(s):  
Early Stage ◽  
Maya Lowlands ◽  
Geographic Scale ◽  
Tool Manufacture ◽  
Specialized Production ◽  
Production And Consumption ◽  
Ancient Times ◽  
Maya Area ◽  
Analytical Approaches ◽  
Comparative Examination

AbstractIt has been known for several decades that certain regions of the Maya Lowlands were characterized by specialized production of chert tools in ancient times. The extent, intensity, organization, and net social effects of centralized lithic production in the Maya area as a whole, however, are not well understood. In order to address issues of broader relevance to social and economic processes, lithicists working in the Maya region need to develop analytical approaches suited to the study of complex economies. The research presented here attempts to establish simple baseline measures for use in comparing the production of siliceous stone tools, both formal and expedient, at different scales across the Maya area. Scholarship in this region has been chronically plagued by prolonged, unresolved debates—mostly a factor of the multitude of single-site-focused projects employing different methodologies and research emphases. The present study therefore proposes a new direction in Maya lithic studies with the goal of enhancing comparability of data on ancient economic structure through the use of standardized statistics that facilitate spatial analysis. Using the proportion of early-stage core reduction debris to the total of all debitagefrom a given context, for instance, enables the analyst to roughly assess the amount of tool manufacture taking place locally. By extension, inferences can be made about the degree of economic integration and interdependence characterizing any given geographic scale, including the architectural group, site, region, and so on. Preliminary analysis of patterns in early-stage reduction illustrates differential spatial distributions of chert tool production and consumption at several scales from across the southern Lowlands, allowing for the refinement of current models of ancient Maya lithic economy.

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