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Article
Publication date: 1 April 1956

An axial flow turbojet engine in which the mean direction of flow of working fluid past any moving blade is substantially free from radial components comprising a casing;…

Abstract

An axial flow turbojet engine in which the mean direction of flow of working fluid past any moving blade is substantially free from radial components comprising a casing; an air intake in said casing; a low‐pressure axial‐flow compressor mounted in said casing, connected directly to said air intake to receive air through it and having a plurality of rows of moving blades whereof the first row has a hub tip ratio between 0·4 and 0·5; a high‐pressure axial flow compressor mounted in said casing, connected directly to said low‐pressure compressor to receive substantially the whole of the air compressed by said low‐pressure compressor and having a plurality of rows of moving blades; combustion equipment mounted in said casing and connected directly to said high‐pressure compressor to receive substantially the whole of the air compressed by said high‐pressure compressor; a single‐stage axial‐flow high‐pressure turbine mounted in said casing, connected directly to said combustion equipment to receive the products of combustion, and drivingly connected to said high‐pressure compressor, the power developed by said high‐pressure turbine being substantially wholly absorbed by said high‐pressure compressor; and a single‐stage axial‐flow low‐pressure turbine mounted in said casing, connected directly to said high‐pressure turbine to receive the exhaust from it and drivingly connected to said low‐pressure compressor, the power developed by said low‐pressure turbine being substantially wholly absorbed by said low‐pressure compressor; in which engine the ratio of the tip diameter of said low pressure turbine to the tip diameter of said first row of moving blades of said low pressure compressor is between 1 and 1·1; and the ratio between the power absorbed by the high‐pressure compressor and the power absorbed by the low‐pressure compressor is between 2 and 2·5 and the tip diameter of said first row of moving blades of said low pressure compressor is greater than the tip diameter of any other row of moving blades of either of said compressors, and the tip diameter of said low pressure turbine is greater than the tip diameter of said high pressure turbine.

Details

Aircraft Engineering and Aerospace Technology, vol. 28 no. 4
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 10 June 2021

Chunxiao Jiao, Jianghai Xu, Donglin Zou, Na Ta and Zhushi Rao

The purpose of this paper is to study the flow field characteristics of the micro-scale textured bearing surfaces using the lattice Boltzmann method based on the…

Abstract

Purpose

The purpose of this paper is to study the flow field characteristics of the micro-scale textured bearing surfaces using the lattice Boltzmann method based on the microscopic dynamics of the fluid.

Design/methodology/approach

Considering the inertia effects and the micro-scale effects, the models of a single micro-scale texture unit cell with different shapes and different film thickness ratios are established. The influence of pressure difference between inlet and outlet of the unit cell on flow characteristics is studied.

Findings

The surface pressure distribution, flow patterns and pressure contours in the flow field are obtained. The results reveal that the pressure difference has a significant influence on the characteristics of the micro-textured flow field.

Originality/value

The results have certain guiding significance for further step investigation on microscopic lubrication mechanism of the water-lubricated polymer bearings.

Details

Industrial Lubrication and Tribology, vol. 73 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 21 October 2021

Houda Barhoumi, Saber Marzougui and Saber Ben Abdessalem

The conception of a compression garment that applies a desired interface pressure level has been a great challenge for therapists and compression garment manufacturers…

Abstract

Purpose

The conception of a compression garment that applies a desired interface pressure level has been a great challenge for therapists and compression garment manufacturers even today. The purpose of this study is to develop a new method for designing a compression legging that exerts Class I interface pressure to the lower limb.

Design/methodology/approach

This research presents a new method for the design of Class I compression garment. It consists of theoretically calculating the circumferences of the Class I compression legging based on the reduction factors. To assess the effectiveness of the method, we used both objective and subjective evaluations. For the objective evaluation, we have developed a measuring device to measure Class I legging interface pressure in different measuring points using a force pressure sensor. Concerning the subjective evaluation, 10 healthy female subjects agreed to take part in this study in order to evaluate the ergonomic comfort when wearing the designed compression legging.

Findings

Participating subjects delivered their feeling about comfort and motion restriction during the use of the legging. Referring to the volunteers’ answers, the Class I compression legging can be described as comfortable and has a satisfactory fit during wear.

Originality/value

The important feature of this study was the effectiveness of the new designing method in producing a compression legging that delivers the desired amount of pressure and offers a comfort sensation during wear. The outcome of this research is a new method that could be used to create a variety of compression garments that can apply different pressure levels.

Details

International Journal of Clothing Science and Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 22 October 2021

Meehee Cho and Joanne Jung-Eun Yoo

Today’s consumers are aware of restaurants’ effects on the environment and pressure them to implement green practices. As restaurant success largely depends on how…

Abstract

Purpose

Today’s consumers are aware of restaurants’ effects on the environment and pressure them to implement green practices. As restaurant success largely depends on how employees meet customer expectations, employee green creative behavior (EGCB) is critical. Therefore, this study aims to investigate how to enhance EGCB by integrating a comprehensive set of three-dimensional components: external, organizational and individual factors.

Design/methodology/approach

Data analysis was conducted using responses from full-time employees in the US restaurant industry. The PROCESS macro was used to test the direct and indirect relationships between the study variables. A series of mediation analyzes were conducted to investigate the mediation effects of “restaurant ethical standards” and “employee green passion” on their relationships to “customer pressure” and EGCB.

Findings

The results verified a direct effect of “customer pressure” on “restaurant ethical standards” and EGCB. The study also demonstrated positive direct relationships of “restaurant ethical standards” – “employee green passion” and “employee green passion” – EGCB. The result showed that “restaurant ethical standards” and “employee green passion” sequentially explained the partial impact of “customer pressure” on EGCB.

Practical implications

The study recommends that restaurant managers acknowledge growing customer environmentalism and prepare to address their customers’ stricter green requirements. Restaurants need to review their ethical standards on a regular basis to meet rising customer pressure. The study also offers empirical evidence regarding the importance of selecting employees who are passionate about sustainability and empowering them to encourage their green creative behavior.

Originality/value

Although past studies have introduced various determinants of employee creative behavior, they have mainly focused on organizational and individual-level factors but have ignored a critical external factor, which is customer pressure. The study addresses this research gap by investigating the interrelationships between customer pressure and EGCB through restaurant ethical standards (organizational-level) and employee green passion (individual-level).

Details

International Journal of Contemporary Hospitality Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0959-6119

Keywords

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Article
Publication date: 25 October 2021

Philippe Gilotte, Iraj Mortazavi, Alfonso Colon de Carvajal, Stephie Edwige and Christian Navid Nayeri

The purpose of this paper is to study pressure measurement correlations, as the location of the pressure sensors should enable to capture variation of the drag force…

Abstract

Purpose

The purpose of this paper is to study pressure measurement correlations, as the location of the pressure sensors should enable to capture variation of the drag force depending on the yaw angle and some geometrical modifications.

Design/methodology/approach

The present aerodynamical study, performed on a reduced scale mock-up representing a sport utility vehicle, involves both numerical and experimental investigations. Experiments performed in a wind tunnel facility deal with drag and pressure measurements related to the side wind variation. The pressure sensor locations are deduced from wall streamlines computed from large eddy simulation results on the external surfaces of the mock-up.

Findings

After validation of the drag coefficient (Cd) values computed with an aerodynamic balance, measurements should only imply pressure tap mounted on the vehicle to perform real driving emission (RDE) tests.

Originality/value

Relation presented in this paper between pressure coefficients measured on a side sensor and the drag coefficient data must enable to better quantify the drag force contribution of a ground vehicle in RDE tests.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 8 February 2021

Qiancheng Qin, Xue-Feng Wang, Rufu Hu and Xiaomin Cheng

This study aims to investigate the effects of single dent on the film thickness and pressure in elastohydrodynamically lubricated (EHL) point contacts by numerical analysis.

Abstract

Purpose

This study aims to investigate the effects of single dent on the film thickness and pressure in elastohydrodynamically lubricated (EHL) point contacts by numerical analysis.

Design/methodology/approach

The governing equations of single dent were established and then the variations of the film thickness and pressure induced by the applied load, the entrainment velocity and the ball radius were investigated. Meanwhile, the film thickness and pressure under smooth and dented surfaces were compared with each other.

Findings

The dent enhances both the maximum pressure and the second pressure peak. The minimum film thickness arises before the dent under certain conditions. In the meantime, the pressure decreases at the inside of the dent and the film thickness is just the reverse. The entrainment velocity remarkably affects the overall film thickness, whereas the rest of the input parameters mainly decides the details of the film curve. All input parameters remarkably affect the overall pressure, especially the maximum pressure.

Originality/value

This work is helpful to understanding the effect of the single dent on the lubricating properties of EHL point contacts.

Details

Industrial Lubrication and Tribology, vol. 73 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

Content available
Article
Publication date: 4 October 2021

Katri Kauppi and Davide Luzzini

Increasing amount of empirical research in operations and supply chain management is using institutional theory as its theoretical lens. Yet, a common scale to measure the…

Abstract

Purpose

Increasing amount of empirical research in operations and supply chain management is using institutional theory as its theoretical lens. Yet, a common scale to measure the three institutional pressures – coercive, mimetic and normative – is lacking. Many studies use proxies or a single, grouped, construct of external pressures which present methodological challenges. This study aims to present the development of multi-item scales to measure institutional pressures (in a purchasing context).

Design/methodology/approach

First, items were generated based on the theoretical construct definitions. These items were then tested through academic sorting and an international survey. The first empirical testing failed to produce reliable and valid scales, and further refinement and analysis revealed that coercive pressure splits into two separate constructs. A second q-sorting was then conducted with purchasing practitioners, followed by another survey in Italy to verify the new measurement scale for four institutional pressures.

Findings

The multimethod and multistage measurement development reveals that empirically the three institutional pressures actually turn into four pressures. The theoretical construct of coercive pressure splits into two distinct constructs: coercive market pressure and coercive regulatory pressure.

Originality/value

The results of the paper, namely, the measurement scales, are an important theoretical and methodological contribution to future empirical research. They present a much-needed measurement for these theoretical constructs increasingly used in management research.

Details

Supply Chain Management: An International Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1359-8546

Keywords

Content available
Article
Publication date: 16 September 2021

Hui-Ming Kuo, Tse-Lu Chen and Chung-Shan Yang

The purpose of this study is to empirically evaluate the impact of coercive pressure, normative pressure and mimetic pressure on digital transformation and benefits in the…

Abstract

Purpose

The purpose of this study is to empirically evaluate the impact of coercive pressure, normative pressure and mimetic pressure on digital transformation and benefits in the maritime shipping context.

Design/methodology/approach

The authors collect data from a survey of 119 shipping companies, shipping agencies, port corporations and shipping forwarders in Taiwan and apply a structural equation model to test the research hypotheses.

Findings

Four conclusions can be drawn: First, digital transformation mainly results from coercive pressure and mimetic pressure. Second, another positive and important source of pressure for shipping digital transformation is the fact that competitors are gradually undergoing digital transformation and have gained recognition from customers. Third, shipping professional organizations and association (e.g. IACS, IAPH, Baltic International Maritime Commission) must keep up with the trend toward digital transformation and put forward guidelines and recommendations that can be followed in order to lead the maritime shipping industry. Fourth, digital transformation has great potential to help deliver the benefits (i.e. improve efficiency, relationship with customers and sustainability).

Originality/value

This research explores the digital transformation of the shipping industry through the lens of institutional theory. The results show that digital transformation is mainly due to coercive pressure and mimetic pressure. Digital transformation has been found to bring benefits that can help shipping operators allocate their resources effectively, thereby increasing operational efficiency, improving relationships with customers and enhancing sustainability.

Details

Maritime Business Review, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2397-3757

Keywords

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Article
Publication date: 6 July 2020

Igor S. Nadezhdin and Aleksey G. Goryunov

Differential pressure is an important technological parameter, one urgent task of which is control and measurement. To date, the lion’s share of research in this area has…

Abstract

Purpose

Differential pressure is an important technological parameter, one urgent task of which is control and measurement. To date, the lion’s share of research in this area has focused on the development and improvement of differential pressure sensors. The purpose of this paper is to develop a smart differential pressure sensor with improved operational and metrological characteristics.

Design/methodology/approach

The operating principle of the developed pressure sensor is based on the capacitive measurement principle. The measuring unit of the developed pressure sensor is based on a differential capacitive sensitive element. Programmable system-on-chip (PSoC) technology has been used to develop the electronics unit.

Findings

The use of a differential capacitive sensitive element allows the unit to compensate for the influence of interference (for example, temperature) on the measurement result. With the use of PSoC technology, it is also possible to increase the noise immunity of the developed smart differential pressure sensor and provide an unparalleled combination of flexibility and integration of analog and digital functionality.

Originality/value

The use of PSoC technology in the developed smart differential pressure sensor has many indisputable advantages, as the size of the entire circuit can be minimized. As a result, the circuit has improved noise immunity. Accordingly, the procedure for debugging and changing the software of the electronics unit is simplified. These features make development and manufacturing cost effective.

Details

Sensor Review, vol. 40 no. 5
Type: Research Article
ISSN: 0260-2288

Keywords

Content available
Article
Publication date: 14 August 2021

Susan Danissa Calderón Urbina, Antonios Stamatogiannakis and Dilney Goncalves

This study aims to introduce the duration of uniqueness, an important dimension of unique products. It studies how choices between products with long versus short duration…

Abstract

Purpose

This study aims to introduce the duration of uniqueness, an important dimension of unique products. It studies how choices between products with long versus short duration of uniqueness are influenced by the interaction between pressure and consumers’ need for uniqueness (NFU).

Design/methodology/approach

This research uses a multi-method study approach. A pilot field-study tested the novelty and importance of the research by asking retail professionals to predict the choice of a hypothetical consumer. A retrospective study assessed the importance of duration of uniqueness in unique product choices, by asking consumers about a real and recent unique product purchase. Four additional experimental studies directly tested hypotheses by manipulating pressure and by measuring or manipulating uniqueness motivations.

Findings

The pilot field-study showed the novelty and relevance of this research for professionals. Study 1 revealed that, retrospectively, uniqueness duration was considered important for the choice of unique products, by high-NFU consumers under pressure. Studies 2 and 3 demonstrated that pressure increases the tendency of high-NFU, but not low-NFU, consumers to choose products with long over short uniqueness duration. Study 4 provided initial evidence for the process behind the effect. Study 5 showed that considerations of uniqueness duration when choosing mediated the effects.

Research limitations/implications

The results of the pilot field-study and retrospective study might be affected by recall bias or lay theories. The findings need to be replicated with other sources of pressure and uniqueness. This calls for further research.

Practical implications

Results are important for companies marketing unique products and they suggest that pressure-based marketing appeals can be used strategically to increase sales of products with long uniqueness duration but decrease sales of products with short uniqueness duration. Although the research provides these guidelines, managers should consider the ethical implications of pressure strategies.

Originality/value

This is the first attempt to empirically investigate the duration of uniqueness. Although extant research has examined choices between products with different degrees of uniqueness, this research studies choice of products with similar degrees of uniqueness, but different uniqueness duration. Thus, this research adds to the scarce literature studying the duration of symbolic benefits. Moreover, although pressure and NFU frequently co-exist in uniqueness consumption settings, this study is the first to study their joint effects.

Details

European Journal of Marketing, vol. 55 no. 13
Type: Research Article
ISSN: 0309-0566

Keywords

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