scholarly journals Life Cycle Environmental and Economic Comparison of Water Droplet Machining and Traditional Abrasive Waterjet Cutting

2021 ◽  
Vol 13 (21) ◽  
pp. 12275
Author(s):  
Giovanni Guglielmi ◽  
Benjamin Mitchell ◽  
Cuihong Song ◽  
Brad L. Kinsey ◽  
Weiwei Mo
Keyword(s):  
Life Cycle ◽  
Water Droplet ◽  
Life Cycle Cost ◽  
High Speed ◽  
Metal Cutting ◽  
Economic Impacts ◽  
Sensitivity Analyses ◽  
Abrasive Waterjet ◽  
Waterjet Cutting ◽  
Awj Cutting

Abrasive waterjet (AWJ) cutting is a manufacturing technique, which uses a high-speed waterjet as the transport medium for abrasive particles to erode and cut through metal workpieces. The use of abrasives has significant environmental impacts and leads to the high operating costs of AWJ cutting. Therefore, it is important to investigate whether other metal cutting approaches can perform the same tasks with reduced environmental and economic impacts. One such manufacturing innovation is water droplet machining (WDM). In this process, the waterjet, which is immersed in a sub-atmospheric pressure environment, is discretized into a train of high velocity water droplets, which are able to erode and cut through the metal workpiece without abrasives. However, the cutting velocity of WDM is two orders of magnitude slower than AWJ. In this paper, a comparative life cycle and life cycle cost assessments were performed to determine which waterjet cutting technology is more beneficial to the environment and cost-efficient, considering their impacts from cradle to grave. The results show lower environmental and economic impacts for AWJ compared to WDM due to the AWJ’s ability to cut more metal over the service life than the WDM. Further sensitivity analyses give insight into how the change in abrasive rate is the most sensitive input for the AWJ, whereas the machine lifetime and electricity usage are the most sensitive inputs for the WDM. These results provide a valuable comparison between these alternative waterjet cutting technologies.

The Influence of Engine Characteristics on Patrol Aircraft Life Cycle Cost Optimization

1982 ◽  
Author(s):  
A. J. Schuetz
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
High Speed ◽  
Cost Optimization ◽  
Life Cycle Costs ◽  
Design Constraints ◽  
Performance Requirements ◽  
Aircraft Performance ◽  
Antisubmarine Warfare ◽  
Flight Profile

A conceptual design study has been conducted for an all-new, land-based patrol aircraft for the U.S. Navy. The selected propulsion system was a conceptual high-speed turboprop. An antisubmarine warfare mission was chosen for the design flight profile. Probable peacetime utilization was postulated so that the engine duty cycle could be estimated. Aircraft designs were optimized for minimum takeoff gross weight (TOGW) and for minimum life cycle cost (LCC). It was shown that the aircraft performance requirements and design constraints bound the optimization process so tightly that the same point design is obtained for both TOGW and LCC criteria. The contribution of the engine costs to the overall life cycle costs was examined. The sensitivity of the aircraft optimization to the engine characteristics — specific fuel consumption (SFC), length, diameter, and cost — was analyzed. It was determined that SFC is the most significant engine characteristic.

Development of ice abrasive waterjet cutting technology

2017 ◽  
Vol 2 (81) ◽  
pp. 76-84
Author(s):  
J. Valentinčič ◽  
A. Lebar ◽  
I. Sabotin ◽  
P. Drešar ◽  
M. Jerman
Keyword(s):  
High Speed ◽  
Power Plants ◽  
Water Jet ◽  
Abrasive Waterjet ◽  
Abrasive Water Jet ◽  
Influence Of Process Parameters ◽  
Cutting Head ◽  
Ice Particles ◽  
Main Challenge ◽  
Awj Cutting

Purpose: Abrasive water jet (AWJ) cutting uses mineral abrasive to cut practically all materials. In ice abrasive water jet (IAWJ) cutting, the ice particles are used as abrasive. IAWJ is under development with the aim to bridge the gap in productivity between the abrasive water jet (AWJ) and water jet (WJ) cutting. It is clean and environmentally friendlier in comparison with AWJ, while its cutting efficiency could be better than WJ. Design/methodology/approach: The main challenge is to provide very cold and thus hard ice particles in the cutting zone, thus cooling the water under high pressure is utilized. Further on, two approaches to obtain ice particles in the water are studied, namely generation of ice particles in the cutting head and generation of ice particles outside of the cutting head and adding them to the jet similar as in AWJ technology. In this process it is essential to monitor and control the temperature occurring in the system. Findings: To have ice particles with suitable mechanical properties in the cutting process, the water have to be precooled, ice particles generated outside the cutting head and later added to the jet. The results show that, contrary to the common believe, the water temperature is not significantly changed when passing through the water nozzle. Research limitations/implications: The presence of ice particles was only indirectly identified. In the future, a special high speed camera will be used to study the influence of process parameters on ice particle distribution. Practical implications: IAWJ technology produces much less sludge (waste abrasive and removed workpiece material mixed with water) than AWJ technology which is beneficial in e.g. disintegration of nuclear power plants. IAWJ technology has also great potential in the food and medical industries for applications, where bacteria growth is not desired. Originality/value: The paper presents the latest achievements of IAWJ technology.

Safety management of high-speed railway transport

2017 ◽  
pp. 105-118
Author(s):  
Vladimir Shmatchenko ◽  
Pavel Plekhanov
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
High Speed ◽  
A Priori Estimates ◽  
Safety Management ◽  
Practical Importance ◽  
International Standards ◽  
Railway Transport ◽  
High Speed Railway ◽  
Safety Control

Objective: To determine the main approaches to safety management of high-speed railway transport on the basis of modern international and domestic practices in the specified sphere. Methods: Analysis methods of security risks on railway transport were considered in accordance with modern international standards of management of interconnected indices’ complex, which include reliability, availability, maintainability and safety and cost (Life Cycle Cost – LCC) at all stages of transportation systems’ life cycle: EN 50126 (IEC 62278), EN 50128 (IEC 62279), EN 50129 (IEC 62425) and IEC 60300-3-3. Results: The main approaches to safety measures of high-speed railway lines (VSM) were detected. The former involve using a lifecycle concept of engineering systems and facilities, management methodology of RAMS/LCC interconnected indices’ complex at all stages of a life cycle, wide application of the process approach and the tools of quality and safety management systems, development and implementation of technological maturity assessment methodology for security management activities, as well as object-oriented and coherent improvement of regulatory base, the systems of administrative and control and permission authorities, technical and technological development, management of external, inland and allocated risks under market relations. Practical importance: The examined approaches of VSM safety control make it possible to obtain a priori estimates of safety control processes and thus determine the achieved level of safety together with the levels of technological maturity of railway organizations’ processes.

scholarly journals Basic abrasive waterjet cutting process parameters

2018 ◽  
Vol 19 (12) ◽  
pp. 654-657
Author(s):  
Sławomir Spadło ◽  
Daniel Krajcarz
Keyword(s):  
Water Pressure ◽  
Cutting Speed ◽  
Cutting Process ◽  
Machining Process ◽  
Abrasive Waterjet ◽  
Maximum Efficiency ◽  
Waterjet Cutting ◽  
Abrasive Waterjet Cutting ◽  
Water Jet Cutting ◽  
Awj Cutting

The article presents the basic parameters characterizing the abrasive water jet cutting, such as: water pressure (pw), cutting speed (vf), abrasive mass flow rate (ma) and the distance between forming nozzle and the cut material (l). Each of the mentioned parameters of the cutting process has been described in a separate subsection. The authors of the article focused primarily on the aspects related to the possibility of achieving maximum efficiency of the machining process while maintaining the assumed quality of cutting for individual cutting parameters. A detailed analysis of the topic was enabled the authors own research and an available literature on this subject. A closer understanding of the phenomena accompanying the abrasive waterjet cutting (AWJ) process and obtaining characteristics that would describe the influence of the tested output parameters in the function of input parameters will enable optimization of AWJ cutting process.

scholarly journals Modern regulations of safety assurance for maglev transportation

2015 ◽  
Vol 1 (2) ◽  
pp. 127-142 ◽  
Author(s):  
Vladimir Vladimirovich Shmatchenko ◽  
Pavel Andreevich Plekhanov
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
High Speed ◽  
Safety Management ◽  
Estimation Methods ◽  
Transport Systems ◽  
The European Union ◽  
New Approach ◽  
Look Ahead ◽  
Railway Safety

In article regulatory framework of maglev are considered, the international experience is analysed and conclusions for Russian practice are drawn. Modern management methods of safety of transport systems are based on principles of advance to occurrence of dangerous events. These principles include: - application of forecasting methods (aprioristic estimation methods) at an estimation of safety and substantiation of safety measures - a principle of «the new approach»; - estimation of safety taking into account risk from action of casual and systematic failures; - safety management in a complex with management of reliability, availability, maintainability, material support and life cycle cost. Necessity of application of «the new approach» to railway safety, including the high-speed railways, formally has been established by the Railway Safety Directive 2004/49/EC. This Directive orders to use: - analysis and management of risk at all life cycle stages of the technical systems participating in formation of traffic service, and at early stages of life cycle are made look-ahead estimations of risks which are compared with admissible values of risk; - common safety targets, common safety indicators and common safety methods on all space of the European Union; - common approaches to certification of safety and the harmonised supervision bodies; - common typical safety management system, based on ISO 9001principles. For activity expansion on performance of Railway Safety Directive of the European Committee for Electrotechnical Standardization CENELEC have been developed and now frame standards EN 50126, EN 50128, EN 50129 are applied.

scholarly journals Selection of the Most Sustainable Renewable Energy System for Bozcaada Island: Wind vs. Photovoltaic

2019 ◽  
Vol 11 (15) ◽  
pp. 4098 ◽  
Author(s):  
Elif Oğuz ◽  
Ayşe Eylül Şentürk
Keyword(s):  
Renewable Energy ◽  
Life Cycle ◽  
Production Process ◽  
Life Cycle Cost ◽  
Energy Production ◽  
Economic Impacts ◽  
Unit Cost ◽  
Energy Systems ◽  
Renewable Energy Systems ◽  
Photovoltaic Power

Energy production without destroying the environment has been one of the most crucial issues for people living in today’s world. In order to analyze whole environmental and/or economic impacts of the energy production process, life cycle assessment (LCA) and life cycle cost (LCC) are widely used. In this study, two distinct renewable energy systems are assessed. First, a land-based wind farm, which has been operating in Bozcaada Island since 2000, is compared to a proposed solar photovoltaic power plant in terms of Energy Pay-Back Time (EPBT) periods and greenhouse gas (GHG) emissions and life cycle cost. The energy production process including the recycling phase evaluated “from cradle to grave” using GaBi software for both cases. All scenarios are compared by considering different impact categories such as global warming potential (GWP), acidification potential (AP), and eutrophication potential (EP). Following this, levelized unit cost to produce 1 MWh electricity (LUCE) is calculated for both systems. This study revealed that LCA and LCCA are useful and practical tools that help to determine drawbacks and benefits of different renewable energy systems considering their long-term environmental and economic impacts. Our findings show that onshore wind farms have a number of benefits than proposed photovoltaic power plants in terms of environmental and cost aspects.

scholarly journals Uncertainty and sensitivity analyses of ballast life-cycle cost and payback period

2000 ◽  
Author(s):  
James E. McMahon ◽  
Xiaomin Liu ◽  
Ike Turiel ◽  
Sajid Hakim ◽  
Diane Fisher
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Payback Period ◽  
Sensitivity Analyses
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