4,007 research outputs found
THE STANDARD SINGLE COST METHOD AND THE EFFICIENCY OF INDUSTRIAL COMPANIES’ MANAGEMENT
This article briefly describes the premises for the application of the standard direct cost calculation method in industry, the standard single cost calculation method, the stages of standard cost calculation per product and the calculation methods of standards per product. It also briefly underlines the possibilities of cost calculation and monitoring of deviation of the costs of raw materials and other materials as compared to the pre-established standard costs.Calculation method, standard direct cost method, accounting organisation, calculation of deviation
Flow-based approach for holistic factory engineering and design
The engineering of future factories requires digital tools along life cycle phases from investment planning to ramp-up. Manufacturers need scientific-based integrated highly dynamic data management systems for the participative and integrated factory planning. The paper presents a new approach for the continuously integrated product design, factory and process planning, through a service-oriented architecture for the implementation of digital factory tools. A first prototype of the digital factory framework has been realised by a comprehensive scenario for factory, equipment and process planning. The phases of factory operation and equipment maintenance are integrated, as well. The enabling technologies, grid computing and workflow management, which supports the comprehensive and integrated engineering of products, factory and processes are shortly introduced
Deriving a systematic approach to changeable manufacturing system design
It has long been argued that Factories are long life and complex products. The complexity of designing factories, and their underlying manufacturing systems, is further amplified when dealing with continuously changing customer demands. At the same time, due to research fragmentation, little if any scientific explanations are available supporting and exploiting the paradigm that "factories are products". In order to address this weakness, this paper presents research results arising from a comparative analysis of systematic "product design" and "manufacturing system design" approaches. The contribution emerging from this research is an integrated systematic design approach to changeable manufacturing systems, based on scientific concepts founded upon product design theories, and is explained through a case study in the paper. This research is part of collaboration between the CERU University of Malta and IAO Fraunhofer aimed at developing a digital decision support tool for planning changeable manufacturing systems.peer-reviewe
Energy landscape and band-structure tuning in realistic MoS2/MoSe2 heterostructures
While monolayer forms of two-dimensional materials are well characterized both experimentally and theoretically, properties of bilayer heterostructures are not nearly so well known. We employ high-accuracy linear-scaling density functional theory calculations utilizing nonlocal van der Waals functionals to explore the possible constructions of the MoS2/MoSe2 interface. Utilizing large supercells, we vary rotation, translation, and separation of the layers without introducing unrealistic strain. The energy landscape shows very low variations under rotation, with no strongly preferred alignments. By unfolding the spectral function into the primitive cells, we show that the monolayers are more independent than in homo-bilayers and that the electronic band structure of each layer is tunable through rotation, thus influencing hole effective masses.The authors acknowledge the support of the Winton Programme for the Physics of Sustainability. Computing resources were provided by the Darwin Supercomputer of the University of Cambridge High Performance Computing Service and the Argonne Leadership Computing Facility at Argonne National Laboratory, supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-06CH11357. G.C.C. acknowledges the support of the Cambridge Home and EU Scholarship Scheme.This is the accepted manuscript of a paper published in Physical Review B (Constantinescu GC, Hine NDM, Physical Review B, 2015, 91, 195416, doi:10.1103/PhysRevB.91.195416). The final version is available at http://dx.doi.org/10.1103/PhysRevB.91.19541
Asymptotic results for renewal risk models with risky investments
We consider a renewal jump-diffusion process, more specifically a renewal insurance risk model with investments in a stock whose price is modeled by a geometric Brownian motion. Using Laplace transforms and regular variation theory, we introduce a transparent and unifying analytic method for investigating the asymptotic behavior of ruin probabilities and related quantities, in models with light- or heavy-tailed jumps, whenever the distribution of the time between jumps has rational Laplace transform
Field Data vs. Theoretical Model to Quantify Drilling Efficiency and Disruption
Mechanical and kinematics data at the bit have been collected during drilling operations and organized to identify optimal drilling efficiency. Transitional conditions towards abnormal behavior have been distinguished. Normal drilling is usually characterized by regular linear relationships between global control variables at the bit, which approximately correspond to an up scaling of a local Mohr Coulomb type failure mechanism of the rock. Most of our experimental data confirm this classical disposition. However, considerable departure from these relationships is noted, especially when there is BHA resonance or when there is partial balling at the bit. The field tests presented here allows us to verify classical theory and to draw up new guidelines for behavior in non- optimal or dangerous, evolving operating conditions, such as those that occur under poor cleaning conditions. The main features of a mechanical structuring model involving transition towards low efficiency conditions are presented, and it is shown how this model confirms our interpretation of field data. The model couples the drillability of rock and the general dynamics of the bit in an original and synthetic way. It makes it possible to understand and test the sensitivity of bit response to variables such as "weight on hook", torque on the drillstring and flow rate of the fluid
A case for assisting ‘product family’ manufacturing system designers
Manufacturing system design is a complex and demanding activity and the system designer has to take many factors into
consideration during the development process including the demand and technological requirements of the products or product
families. Central to this activity is the synthesis decision making process, during which the designer defines the elements that will
make up the manufacturing system. This research identifies in the decision making process a critical activity and contributes a
phenomena that can be used by a framework to support designers to address complex issues such as changeability and the evolution
of products over the manufacturing system life-cycle.This research work was partially funded through an
ERDF Project (Project No. ERDF083). The first and
second authors would therefore like to thank the Malta
Council for Science and Technology (MCST) who is
administering this project.peer-reviewe
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