225 research outputs found

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    The effect of cutting conditions on power inputs when machining

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    Any technological process involving modification of material properties or product form necessitates consumption of a certain power amount. When developing new technologies one should take into account the benefits of their implementation vs. arising power inputs. It is revealed that procedures of edge cutting machining are the most energy-efficient amongst the present day forming procedures such as physical and technical methods including electrochemical, electroerosion, ultrasound, and laser processing, rapid prototyping technologies etc, such as physical and technical methods including electrochemical, electroerosion, ultrasound, and laser processing, rapid prototyping technologies etc. An expanded formula for calculation of power inputs is deduced, which takes into consideration the mode of cutting together with the tip radius, the form of the replaceable multifaceted insert and its wear. Having taken as an example cutting of graphite iron by the assembled cutting tools with replaceable multifaceted inserts the authors point at better power efficiency of high feeding cutting in comparison with high-speed cutting

    Analysis of the Lifecycle of Mechanical Engineering Products

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    Principal phases of the lifecycle of mechanical engineering products are analyzed in the paper. The authors have developed methods and procedures to improve designing, manufacturing, operating and recycling of the machine. It has been revealed that economic lifecycle of the product is a base for appropriate organization of mechanical engineering production. This lifecycle is calculated as a minimal sum total of consumer and producer costs. The machine construction and its manufacturing technology are interrelated through a maximal possible company profit. The products are to be recycled by their producer. Recycling should be considered as a feedback phase, necessary to make the whole lifecycle of the product a constantly functioning self-organizing system. The principles, outlined in this paper can be used as fundamentals to develop an automated PLM-system

    On the Problem of Wear Resistant Coatings Separation From Tools and Machine Elements

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    The article considers separation of wear resistant coatings of tool and engineering materials which arises both during coating fabrication and use of the product. The cause of this phenomenon is assumed to be related to thermal residual stresses generating on the coatingsubstrate border. These stresses have been analyzed and methods are provided to calculate it after produced composite material is cooled down from the temperature of coating synthesis to the ambient temperature. A no-fracture condition has been stated in relation to coatingsubstrate thicknesses, temperature differences and physical and mechanical properties of combined materials. The issue of intermediate layer incorporation with pre-set parameters has been discussed. A co-effect of thermal residual and functional stresses on the strength of the boundary layer has been considered when heating, tension and compression of a product with wear resistant coating. Conclusions have been made, as well as recommendations to improve fracture strength of products with thin wear resistant coatings

    Controlling the type and the form of chip when machining steel

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    The type of the chip produced in the process of machining influences many factors of production process. Controlling the type of chip when cutting metals is important for producing swarf chips and for easing its utilization as well as for protecting the machined surface, cutting tool and the worker. In the given work we provide the experimental data on machining structural steel with implanted tool. The authors show that it is possible to control the chip formation process to produce the required type of chip by selecting the material for machining the tool surface

    On Organizing Quick Change-Over Mass Production

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    The terms "type of production" and "coefficient of assigning operations" are analyzed. A new method of calculating the optimum production plan based on profit projections is suggested. We recommend using the cycle time values as initial data for designing and developing technology. On the basis of existing techniques used to convert productions we suggest a new approach to production change-over with the service life of manufacturing facilities equal to the time to product's obsolescence. The factors to maximize profits using this change-over method are indicated, with maximum profits being a condition for the organization of quick change-change mass production

    The effect of cutting conditions on power inputs when machining

    Get PDF
    Any technological process involving modification of material properties or product form necessitates consumption of a certain power amount. When developing new technologies one should take into account the benefits of their implementation vs. arising power inputs. It is revealed that procedures of edge cutting machining are the most energy-efficient amongst the present day forming procedures such as physical and technical methods including electrochemical, electroerosion, ultrasound, and laser processing, rapid prototyping technologies etc, such as physical and technical methods including electrochemical, electroerosion, ultrasound, and laser processing, rapid prototyping technologies etc. An expanded formula for calculation of power inputs is deduced, which takes into consideration the mode of cutting together with the tip radius, the form of the replaceable multifaceted insert and its wear. Having taken as an example cutting of graphite iron by the assembled cutting tools with replaceable multifaceted inserts the authors point at better power efficiency of high feeding cutting in comparison with high-speed cutting

    Scale Matters: Institutional Dynamics and Scalar Politics of Conservation Governance in the Pacific Islands

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    In an era of 'global' oceans crisis, marine conservationists have issued a resounding call to increase the spatial scale of ocean conservation. This dissertation examines the drivers and implications of recent efforts to scale up ocean conservation in places simultaneously celebrated for their revival of community-based conservation: the Pacific Islands region, the Micronesian sub-region, and the nation of Palau. Toward this end, this research engages and advances critical human geography theory on scalar politics and institutional theory on the governance of common pool resources to address the overarching questions: why and how are state and non-state actors rescaling ocean conservation, and with what social, political, and institutional consequences? These questions are approached empirically through a multi-sited case study that ethnographically tracks institutions, actors, funding, and agendas from the 10th Conference of the Parties to the Convention on Biological Diversity to five Pacific Island nations and territories, revealing the links among macro and micro level processes in diverse political and geographical spaces. This research conceptualizes the rescaling of ocean conservation as an integral component of social struggles for empowerment. Results illustrate how state and non-state actors pursue their contextually specific goals by working together to scale up the objects of ocean conservation. The means through which they achieve rescaling include discursive framings, performative acts, and institutional changes. Most significantly, these `scalar practices' have resulted in empowerment of environmental non-governmental organizations and Pacific Island governments within multi-level conservation governance processes; accumulation of international attention and funding at the regional level in Micronesia; and reduced local autonomy for conservation governance in Palau. Overall, this work contributes an empirically grounded, theoretically engaged, and policy-relevant analysis of the scalar politics and institutional dynamics that are reshaping the actors, objectives, and institutions of contemporary ocean conservation across multiple levels of governance. Conclusions advance theory on the scalar dimensions of environmental governance by conceptualizing regions as strategically constructed tools of environmental politics; expanding understanding of the form and function of multi-level regimes for the governance of large common pool resources; and advancing constructive theoretical dialogue between critical human geographers and institutional theorists. This work may also inform policy discussions by illuminating complex tradeoffs that result from scalar rearrangements.</p

    Addressing Criticisms of Large-Scale Marine Protected Areas

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    Designated large-scale marine protected areas (LSMPAs, 100,000 or more square kilometers) constitute over two-thirds of the approximately 6.6% of the ocean and approximately 14.5% of the exclusive economic zones within marine protected areas. Although LSMPAs have received support among scientists and conservation bodies for wilderness protection, regional ecological connectivity, and improving resilience to climate change, there are also concerns. We identified 10 common criticisms of LSMPAs along three themes: (1) placement, governance, and management; (2) political expediency; and (3) social–ecological value and cost. Through critical evaluation of scientific evidence, we discuss the value, achievements, challenges, and potential of LSMPAs in these arenas. We conclude that although some criticisms are valid and need addressing, none pertain exclusively to LSMPAs, and many involve challenges ubiquitous in management. We argue that LSMPAs are an important component of a diversified management portfolio that tempers potential losses, hedges against uncertainty, and enhances the probability of achieving sustainably managed oceans

    Embracing conceptual diversity to integrate power and institutional analysis: Introducing a relational typology

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    Within environmental governance scholarship, an increasing interest in integrating the study of power with institutional analysis is generating novel theoretical and empirical perspectives for understanding human-environment relationships. The array of different approaches employed to integrate power into institutionalist work promises a range of insights. However, building a cohesive research agenda depends on efforts to grapple with the conceptual and theoretical diversity that characterizes the study of power. To this end, we introduce a typology of relationships between power and institutions. The typology brings together diverse conceptualizations of power and institutions within a common analytical space and situates them around two overarching research questions: How does power shape institutions? And how do institutions shape power? The structure of the typology aids researchers in generating specific, operationalizable research questions within the broader research agenda on power and institutions. In the paper, we describe the theoretical basis for the development of the typology, which draws on political ecology and Bloomington school institutionalism. Then, we employ the typology to organize a review of environmental governance literature on power and institutions. This exercise demonstrates the utility of the typology not only for organizing the currently disjointed body of work on power and institutions but also for identifying new research questions. Furthermore, it facilitates discussions about deeper ontological, epistemological, and methodological challenges associated with bringing together different theoretical approaches. Ultimately, the typology defines pathways for integrating two important disciplines studying environmental governance, political ecology and institutionalism, and facilitates the accumulation of a coherent body of knowledge
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