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1 – 10 of 326Jun Zhu, Wei Luo, Wentao Xv, Shuigen Xv, XinYang Zhang and Jiefang Zhao
This paper aims to study the electrochemical corrosion performance of ultrafine-grained (UFG) Cu bulk in 0.5 M NaCl solution.
Abstract
Purpose
This paper aims to study the electrochemical corrosion performance of ultrafine-grained (UFG) Cu bulk in 0.5 M NaCl solution.
Design/methodology/approach
UFG Cu bulk were prepared by impacting at −196°C and following heat treatment. The electrochemical corrosion behaviors of coarse-grained (CG), impacted and subsequently annealed at 190°C Cu bulks were studied.
Findings
All the bulks displayed typical active-passive-transpassive behaviors (dual passive films without stable passive regions). The resistance to corrosion of impacted Cu bulk was notably superior to that of CG Cu bulk, and subsequently annealing further improved its corrosion resistance.
Social implications
Except for mechanical properties, corrosion performance has been considered to be one of the most important aspects in bulk UFG metallic materials research for the prospective engineering applications.
Originality/value
Cryogenic impacting could effectively reduce grain size of CG Cu bulk to UFG scale and induce high density dislocation. Subsequent annealing resulted in a further decrease of grain size even to nanoscale, as well as nanometer twins. The grain refinement, high density dislocation and annealing twins effectively enhance the passivation capability, resulting in an increase in the corrosion resistance.
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Junli Shi, Junyu Hu, Mingyang Ma and Huaizhi Wang
The purpose of this paper is to present a method for the environmental impact analysis of machine-tool cutting, which enables the detailed analysis of inventory data on resource…
Abstract
Purpose
The purpose of this paper is to present a method for the environmental impact analysis of machine-tool cutting, which enables the detailed analysis of inventory data on resource consumption and waste emissions, as well as the quantitative evaluation of environmental impact.
Design/methodology/approach
The proposed environmental impact analysis method is based on the life cycle assessment (LCA) methodology. In this method, the system boundary of the cutting unit is first defined, and inventory data on energy and material consumptions are analyzed. Subsequently, through classification, five important environmental impact categories are proposed, namely, primary energy demand, global warming potential, acidification potential, eutrophication potential and photochemical ozone creation potential. Finally, the environmental impact results are obtained through characterization and normalization.
Findings
This method is applied on a case study involving a machine-tool turning unit. Results show that primary energy demand and global warming potential exert the serious environmental impact in the turning unit. Suggestions for improving the environmental performance of the machine-tool turning are proposed.
Originality/value
The environmental impact analysis method is applicable to different machine tools and cutting-unit processes. Moreover, it can guide and support the development of green manufacturing by machinery manufacturers.
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A completely novel technology for creating new particulate materials has been developed by the Hosokawa Micron Corporation of Japan and is being marketed in the UK and Eire by its…
Abstract
A completely novel technology for creating new particulate materials has been developed by the Hosokawa Micron Corporation of Japan and is being marketed in the UK and Eire by its subsidiary, Hosokawa Mikropul Ltd.
Madhuri Chandrashekhar Deshpande, Rajesh Chaudhari, Ramesh Narayanan and Harishwar Kale
This study aims to develop indium-based solders for cryogenic applications.
Abstract
Purpose
This study aims to develop indium-based solders for cryogenic applications.
Design/methodology/approach
This paper aims to investigate mechanical properties of indium-based solder formulations at room temperature (RT, 27 °C) as well as at cryogenic temperature (CT, −196 °C) and subsequently to find out their suitability for cryogenic applications. After developing these alloys, mechanical properties such as tensile and impact strength were measured as per American Society for Testing and Materials standards at RT and at CT. Charpy impact test results were used to find out ductile to brittle transition temperature (DBTT). These properties were also evaluated after thermal cycling (TC) to find out effect of thermal stress. Scanning electron microscope analysis was performed to understand fracture mechanism. Results indicate that amongst the solder alloys that have been studied in this work, In-34Bi solder alloy has the best all-round mechanical properties at RT, CT and after TC.
Findings
It can be concluded from the results of this work that In-34Bi solder alloy has best all-round mechanical properties at RT, CT and after TC and therefore is the most appropriate solder alloy amongst the alloys that have been studied in this work for cryogenic applications
Originality/value
DBTT of indium-based solder alloys has not been found out in the work done so far in this category. DBTT is necessary to decide safe working temperature range of the alloy. Also the effect of TC, which is one of the major reasons of failure, was not studied so far. These parameters are studied in this work.
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G. Mishra, S.R. Mohapatra, P.R. Behera, B. Dash, U.K. Mohanty and B.C. Ray
The main objective of this experimental investigation is to assess the effect of thermal and cryogenic treatment on hygrothermally conditioned glass fibre reinforced epoxy matrix…
Abstract
Purpose
The main objective of this experimental investigation is to assess the effect of thermal and cryogenic treatment on hygrothermally conditioned glass fibre reinforced epoxy matrix composites, and the impact on its mechanical properties with change in percentage of individual constituents of the laminates.
Design/methodology/approach
The present investigation is an attempt at evaluating the performance of the laminates subjected to different thermal and cryogenic treatments for varying time with prior hygrothermal treatment. The variability of hygrothermal exposure is in the range of 4‐64 h. Glass fibre reinforced plastics laminates with different weight fractions 0.50‐0.60 of fibre reenforcements were used. The ILSS, which is a matrix dominated was studied by three‐point bend test using INSTRON 1195 material testing machine.
Findings
The post‐hygrothermal treatments (both thermal and cryogenic exposures) resulted in an increase in the rate of desorption of moisture. It is noted that the hygrothermal treatment prior to the exposure to thermal or cryogenic conditioning is the major attribute to the variations in the ILSS values. The extent of demoisturisation of the hygrothermally conditioned composites due to a thermal or a cryogenic exposure is observed to be inversely related to its ILSS, independent of the fibre‐weight fractions. Also the ILSS is inversely related to the fibre‐weight fraction irrespective of the post‐hydrothermal treatment.
Originality/value
The reported data are based on experimental investigations.
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Sanna F. Siddiqui, Andre Archer, Dustin Fandetti and Carl McGee
The aerospace, energy and automotive industries have seen wide use of composite materials because of their excellent mechanical properties, along with the benefit of weight…
Abstract
Purpose
The aerospace, energy and automotive industries have seen wide use of composite materials because of their excellent mechanical properties, along with the benefit of weight reduction savings. As such, the purpose of this study is to provide an understanding of the mechanical performance of these materials under extreme operational conditions characteristic of in-service environments.
Design/methodology/approach
This study is novel in that it has evaluated the tensile performance and fracture response of additively manufactured continuous carbon fiber embedded in an onyx matrix (i.e. nylon with chopped carbon fiber) at cryogenic and room temperatures, for specimens manufactured with an angle between the specimen lying plane and the working build plane of 0°, 45° and 90°.
Findings
Research findings reveal enhanced tensile properties (i.e. ultimate tensile strength and modulus of elasticity) by the 0° (X) built specimens, as compared with the 45° (XZ45) and 90° (Z) built specimens at cryogenic temperature. A reduction in ductility is observed at cryogenic temperature for all build orientations. Fractographic analysis reveals the presence of fiber pullout/elongation, pores within the onyx matrix and chopped carbon fiber near fracture zone of the onyx matrix.
Research limitations/implications
Research findings present tensile properties (i.e. ultimate tensile strength, modulus of elasticity and elongation%) for three-dimensional (3D)-printed onyx with and without reinforcing continuous carbon fiber composites at cryogenic and room temperatures. Reinforcement of continuous carbon fibers and reduction to cryogenic temperatures appears to result, in general, in an increase in the tensile strength and modulus of elasticity, with a reduction in elongation% as compared with the onyx matrix tensile performance reported at room temperature. Fracture analysis reveals continuous carbon fiber pull out for onyx–carbon fiber samples tested at room temperature and cryogenic temperatures, suggesting weak onyx matrix–continuous carbon fiber adhesion.
Originality/value
To the best of the authors’ knowledge, this study is the first study to report on the cryogenic tensile properties and fracture response exhibited by 3D-printed onyx–continuous carbon fiber composites. Evaluating the viability of common commercial 3D printing techniques in producing composite parts to withstand cryogenic temperatures is of critical import, for aerospace applications.
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ELLIOTT A. GREEN and A.W. TURNER
The future of the current family of wide‐bodied transports is examined in the environment of the changing world‐wide fuel supply situation. Synthetic hydrocarbon and cryogenic…
Abstract
The future of the current family of wide‐bodied transports is examined in the environment of the changing world‐wide fuel supply situation. Synthetic hydrocarbon and cryogenic fuels are considered in the context of impact on airline fleets and their maintenance. The probability of the emergence of new technology aircraft, still utilising hydrocarbon fuel is considered in view of the possible shortening of their useful life by the introduction of cryogenic fuels. Possible effects on maintenance of the new technologies which would be included in such aircraft are discussed. Finally, the characteristics of the two most promising cryogenic fuels are compared and the effects of one of these fuels on fuel system design, maintenance, and service as well as facilities and equipment are reviewed.
Arvind Gangoli Rao, Feijia Yin and Jos P. van Buijtenen
– The purpose of this paper is to present a novel hybrid engine concept for a multi-fuel blended wing body (MFBWB) aircraft and assess the performance of this engine concept.
Abstract
Purpose
The purpose of this paper is to present a novel hybrid engine concept for a multi-fuel blended wing body (MFBWB) aircraft and assess the performance of this engine concept.
Design/methodology/approach
The proposed hybrid engine concept has several novel features which include a contra-rotating fan for implementing boundary layer ingestion, dual combustion chambers using cryogenic fuel (liquefied natural gas [LNG] or liquid hydrogen [LH2]) and kerosene in the inter-turbine burner (in flameless combustion mode) and a cooling system for bleed air cooling utilizing the cryogenic fuel. A zero-dimensional thermodynamic model of the proposed hybrid engine is created using Gas Turbine Simulation Program to parametrically analyse the performance of various possible engine architectures. Furthermore, the chosen engine architecture is optimized at a cycle reference point using a developed in-house thermodynamic engine model coupled with genetic algorithm.
Findings
Using LH2 and kerosene, the hybrid engine can theoretically reduce CO2 emissions by around 80 per cent. Using LNG and kerosene, the CO2 emissions are reduced by more than 20 per cent as compared to the baseline engine.
Practical implications
The hybrid engine is being investigated in the AHEAD project co-sponsored by the European Commission. This unique aircraft and engine combination will enable aviation to use cryogenic fuels like LH2 or LNG, and will make aviation sustainable.
Originality/value
The MFBWB concept and the hybrid engine is a novel concept which has not yet been investigated before. The potential implications of this technology are far reaching and will shape the future development in aviation.
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The present study involved the development of a value-added comminution process for different recycled meat processing by-products such as bones for management of waste products…
Abstract
Purpose
The present study involved the development of a value-added comminution process for different recycled meat processing by-products such as bones for management of waste products. The paper aims to discuss these issues.
Design/methodology/approach
An indigenous cryo-grinding system was developed and pilot scale comminution tests were carried out on goat and hen bones under different temperature conditions ranging between −15°C and −40°C and sample pre-conditioning adopting liquid nitrogen as a grinding medium.
Findings
Cryo comminution produces finer, uniform particle sizes, increased specific surface area per unit mass with lesser specific energy consumption in comparison to room temperature comminution. Breakage behavior studies showed that hardness (609-685 MPa) and brittleness (24-29 m−1/2) and strain energy decreased (3.1-1.1 N-m) as the temperature was lowered. Weight mean diameter, specific energy consumption under ambient and cryogenic conditions, respectively, were 125 and 80 μm, 1,303 and 1,108 kJ/kg. The process developed attempts to eliminate environmental pollution by reducing food wastes generated and incorporates value to waste products.
Originality/value
A value-added comminution process for meat processing by-products such as bones was developed to reduce food wastes generated as well as environmental pollution. The process aims to improve public health stressing the importance of recycling through the management of food waste products. Public and private organizations can act as profit centers generating significant revenue and employment by adopting the process.
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Thierry Sibilli, Capucine Senne, Hugo Jouan, Askin T. Isikveren and Sabrina Ayat
With the objective to assess potentially performant hybrid-electric architectures, this paper aims to present an aircraft performance level evaluation, in terms of range and…
Abstract
Purpose
With the objective to assess potentially performant hybrid-electric architectures, this paper aims to present an aircraft performance level evaluation, in terms of range and payload, of the synergies between a hybrid-electric energy system configuration and a cryogenic fuel system.
Design/methodology/approach
An unmanned aerial vehicle (UAV) is modeled using an aircraft performance tool, modified to take into account the hybrid nature of the system. The fuel and thermal management systems are modeled looking to maximize the synergistic effects. The electrical system is defined in series with the thermal engine and the performance, in terms of weight and efficiency, are tracked as a function of the cooling temperature.
Findings
The results show up to a 46 per cent increase in range and up to 7 per cent gain on a payload with a reference hybrid-electric aircraft that uses conventional drop-in JP-8 fuel. The configuration that privileges a reduction in mass of the electric motors by taking advantage of the cryogenic coolant temperature shows the highest benefits. A sensitivity study is also presented showing the dependency on the modeling capabilities.
Practical implications
The synergistic combination of a cryogenic fuel and the additional heat sources of a hybrid-electric system with a tendency to higher electric component efficiency or reduced weight results in a considerable performance increase in terms of both range and payload.
Originality/value
The potential synergies between a cryogenic fuel and the electrical system of a hybrid-electric aircraft seem clear; however, at the present, no detailed performance evaluation at aircraft level that includes the fuel, thermal management and electric systems, has been published.
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