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Article
Publication date: 24 September 2018

Li Wang and Marshall Shibing Jiang

The venture capital syndication brings in various resources for the portfolio firms, which positively affects those firms’ performance, while conflicts within syndicates also have…

Abstract

Purpose

The venture capital syndication brings in various resources for the portfolio firms, which positively affects those firms’ performance, while conflicts within syndicates also have negative impact on the portfolio firms’ performance. This study aims to explore the two opposite effects of the venture capital syndication on the portfolio firms’ operations. Drawing on Ma et al.’s (2013) power source match perspective, the authors examine the effect of (mis)match of power source between ownership and status on the portfolio firms’ performance.

Design/methodology/approach

The study uses panel data from two professional databases containing information about the venture capital-backed firms in China. The fixed effect model is applied to analyze the data.

Findings

This study found that power source match in the venture capital syndicates works positively on the portfolio firms’ performance. This positive relationship is weakened when there is ownership-dominated power source mismatch present.

Practical implications

This study suggests that when new ventures search for venture capital, it is better to allocate greater ownership to the venture capital providers with high-status power, so that ownership power and status power can have a proper match to increase the coordination among venture capital providers, thereby helping portfolio firms perform better.

Originality/value

This study looks into the performance of a portfolio firm when there is power a (mis)match in a venture capital syndication, extending the current literature in this area where only the performance of the venture syndications is examined.

Details

Chinese Management Studies, vol. 12 no. 4
Type: Research Article
ISSN: 1750-614X

Keywords

Article
Publication date: 4 January 2019

Anna Maria Mazur and Roman Domanski

The presented research is carried out in reaction to the soaring costs of fuel and tight control over environmental issues such as carbon dioxide emissions and noise. The purpose…

Abstract

Purpose

The presented research is carried out in reaction to the soaring costs of fuel and tight control over environmental issues such as carbon dioxide emissions and noise. The purpose of this paper is to study the feasibility of applying the environmental-friendly energy source in an unmanned aerial vehicles (UAVs) propulsion system.

Design/methodology/approach

Currently, the majority of UAVs are still powered by conventional combustion engines. An electric propulsion system is most commonly found in civilian micro and mini UAVs. The UAV classification is reviewed in this study. This paper focuses mainly on application of electric propulsion systems in UAVs. Investigated hybrid energy systems consist of fuel cells, Li-ion batteries, super-capacitors and photovoltaic (PV) modules. Current applications of fuel cell systems in UAVs are also presented.

Findings

The conducted research shows that hybridization allows for better energy management and operation of every energy source onboard the UAV within its limits. The hybrid energy system design should be created to maximize system efficiency without compromising the performance of the aircraft.

Practical implications

The presented study highlights the reduction of the energy consumption, necessary to perform the mission and maximizing of the endurance with simultaneous decrease in emissions and noise level.

Originality/value

The conducted research studies the feasibility of implementing the environmental-friendly hybrid electric propulsion systems in UAVs that offers high efficiency, reliability, controllability, lack of thermal and noise signature, thus, providing quiet and clean drive with low vibration levels. This paper highlights the main challenges and current research on fuel cell in aviation and draws attention to fuel cell – electric system modeling, hybridization and energy management.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 5
Type: Research Article
ISSN: 1748-8842

Keywords

Open Access
Article
Publication date: 15 March 2023

Xiao Fan Zhao, Andreas Wimmer and Michael F. Zaeh

The purpose of this paper is to demonstrate the impact of the welding sequence on the substrate plate distortion during the wire and arc additive manufacturing (WAAM) process…

1061

Abstract

Purpose

The purpose of this paper is to demonstrate the impact of the welding sequence on the substrate plate distortion during the wire and arc additive manufacturing (WAAM) process. This paper also aims to show the capability of finite element simulations in the prediction of those thermally induced distortions.

Design/methodology/approach

An experiment was conducted in which solid aluminum blocks were manufactured using two different welding sequences. The distortion of the substrates was measured at predefined positions and converted into bending and torsion values. Subsequently, a weakly coupled thermo-mechanical finite element model was created using the Abaqus simulation software. The model was calibrated and validated with data gathered from the experiments.

Findings

The results of this paper showed that the welding sequence of a part significantly affects the formation of thermally induced distortions of the final part. The calibrated simulation model was able to capture the different distortion behavior attributed to the welding sequences.

Originality/value

Within this work, a simulation model was developed capable of predicting the distortion of WAAM parts in advance. The findings of this paper can be used to improve the design of WAAM welding sequences while avoiding high experimental efforts.

Details

Rapid Prototyping Journal, vol. 29 no. 11
Type: Research Article
ISSN: 1355-2546

Keywords

Open Access
Article
Publication date: 6 March 2020

Cornelis van Dorsser and Poonam Taneja

The paper aims to present an integrated foresight framework and method to support decision-makers who are confronted with today’s complex and rapidly changing world. The method…

3382

Abstract

Purpose

The paper aims to present an integrated foresight framework and method to support decision-makers who are confronted with today’s complex and rapidly changing world. The method aims at reducing the degree of uncertainty by addressing the inertia or duration of unfolding trends and by placing individual trends in a broader context.

Design/methodology/approach

The paper presents a three-layered framework and method for assessing megatrends based on their inertia or duration. It suggests that if long-term trends and key future uncertainties are studied in conjunction at a meta-level and placed in a broader multi-layered framework of trends, it can result in new insights.

Findings

The application of the proposed foresight method helps to systematically place a wide range of unrelated trends and key uncertainties in the context of a broader framework of trends, thereby improving the ability to understand the inertia, direction and mutual interaction of these trends.

Research limitations/implications

The elaboration of identified trends and key uncertainties is partly case-specific and subject to interpretation. It is aimed at illustrating the potential use of the framework.

Practical implications

The paper presents a new approach that may, by itself or in combination with existing foresight methods, offer new means for anticipating future developments.

Social implications

The use of the proposed framework has potential to provide better insight in the complexity of today’s rapid-changing world and the major transitions taking place. It aims to result in sharper foresight by reducing epistemic uncertainty for decision-makers.

Originality/value

The paper demonstrates how megatrends, Kondratieff waves and century-long trends can be placed in an integrated framework and analysed in conjunction.

Details

foresight, vol. 22 no. 2
Type: Research Article
ISSN: 1463-6689

Keywords

Article
Publication date: 6 January 2021

Sa’d Shannak and Artem Malov

This paper aims to discuss opportunities for pairing the carbon dioxide (CO2) points of supply from stationary sources such as power plants, steel and cement production, coal to…

Abstract

Purpose

This paper aims to discuss opportunities for pairing the carbon dioxide (CO2) points of supply from stationary sources such as power plants, steel and cement production, coal to liquid plants and refineries, with potential oil reservoirs in China.

Design/methodology/approach

This study builds a linear optimization model to analyze the tradeoffs in developing CO2-enhance oil recovery (EOR) projects in China for a range of policy options to match points of supply with the points of demand (oil fields). The model works on optimizing CO2 application costs by meeting four principal components; CO2 storage, CO2 capture, transport costs and additional oil recovery.

Findings

This study reveals new opportunities and economic sources to feed CO2-EOR applications and offers reasonable options to supply CO2 for potential points of demand. Furthermore, power plants and coal to liquid industries had the most significant and economic contributions to potential CO2-EOR projects in China. Total annual emission reduction is expected to be 10% (based on 10 Gton annual emissions). The emission reductions and potential CO2 storage from the different industries as follow; 94% from power plants, 4% from biofuel and 2% from coal to liquid plants.

Social implications

Carbon capture and storage (CCS) is one practice aiming to reduce the amounts of anthropogenic emissions of carbon dioxide emitted into the atmosphere and reduce the related social costs. However, given the relatively high cost associated with this practice, coupling it with EOR could offer a significant financial incentive to facilitate the development of CCS projects and meet climate change objectives.

Originality/value

The model used in this study can be straightforwardly adapted to any geographic location where industry and policymakers are looking to simultaneously reduce CO2 emissions while increasing hydrocarbon recovery. The model is highly adaptable to local values in the parameters considered and to include additional local considerations such as geographic variation in capture costs, taxes and premiums to be placed on CO2 capture in so-called “non-attainment zones” where pollution capture make could make a project politically and economically viable. Regardless of how and where this model is applied, it is apparent that CO2 from industrial sources has substantial potential value as a coproduct that offsets its sequestration costs using existing, commercially available CO2-EOR technology, once sources and sinks are optimally paired.

Details

Journal of Science and Technology Policy Management, vol. 12 no. 1
Type: Research Article
ISSN: 2053-4620

Keywords

Article
Publication date: 18 January 2013

Qin Ge, Xinyu Liu, Xiaojuan Chen, Weijun Luo and Guoguo Liu

The purpose of this paper is to report upon high power, internally matched GaN high electron mobility transistors (HEMTs) at Ku band with 1.5 GHz bandwidth, which employ a simple…

Abstract

Purpose

The purpose of this paper is to report upon high power, internally matched GaN high electron mobility transistors (HEMTs) at Ku band with 1.5 GHz bandwidth, which employ a simple and cost‐effective lossless compensated matching technique.

Design/methodology/approach

Two 4 mm gate periphery GaN HEMTs are parallel combined and internally matched with multi‐section reactive impedance transformers at the input and output networks. The output matching network is designed at the upper frequency of the design band for a flat power of the circuit, while the input matching network is designed at the upper frequency for a flat gain.

Findings

With the reactively compensated matching technique, the internally matched GaN HEMTs exhibit a flat saturated output power of 43.2+0.7 dBm and an average power added efficiency of 15 per cent over 12 to 13.5 GHz.

Originality/value

This paper provides useful information for the internally matched GaN HEMTs.

Details

Microelectronics International, vol. 30 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 June 1994

Roger Clarke

Computer matching is a mass surveillance technique involving thecomparison of data about many people, which have been acquired frommultiple sources. Its use offers potential…

1604

Abstract

Computer matching is a mass surveillance technique involving the comparison of data about many people, which have been acquired from multiple sources. Its use offers potential benefits, particularly financial savings. It is also error‐prone, and its power results in threats to established patterns and values. The imperatives of efficiency and equity demand that computer matching be used, and the information privacy interest demands that it be used only where justified, and be subjected to effective controls. Provides background to this important technique, including its development and application in the USA and in Australia, and a detailed technical description. Contends that the technique, its use, and controls over its use are very important issues which demand research. Computing, telecommunications and robotics artefacts which have the capacity to change society radically need to be subjected to early and careful analysis, not only by sociologists, lawyers and philosophers, but also by information technologists themselves.

Details

Information Technology & People, vol. 7 no. 2
Type: Research Article
ISSN: 0959-3845

Keywords

Article
Publication date: 5 July 2013

Michał Gwóźdź

The aim of the research was to find a structure of the power electronics controlled current source with extended pass band, which would better match a source output current within…

Abstract

Purpose

The aim of the research was to find a structure of the power electronics controlled current source with extended pass band, which would better match a source output current within an input (reference) signal. Also, pulse modulation components in output current of current source should be minimized.

Design/methodology/approach

The power electronics controlled current source utilizes both, the concept of the inductor with variable (controlled) inductance located at the output of an inverter and the concept of the multi‐channel (interleaved) inverter. The small signal (linear) and simulation models of an active filter have been investigated.

Findings

The work presents the concept of 1‐phase active shunt filter with utilization of the power electronics current source about extended pass‐band.

Research limitations/implications

The research should be continued to achieve stability of the electrical system with variable parameters of the power network and receiver.

Practical implications

The research will be continued towards realization of a laboratory model of a 3‐phase active shunt filter with the DSP based control module.

Social implications

Social implications are difficult to determine.

Originality/value

The paper presents a new concept of the precision power electronics controlled current source with the extended pass‐band. The controlled current source is the fundamental block of a power electronics active shunt filter.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 31 March 2020

Min Liu, Panpan Xu, Jincan Zhang, Bo Liu and Liwen Zhang

Power amplifiers (PAs) play an important role in wireless communications because they dominate system performance. High-linearity broadband PAs are of great value for potential…

Abstract

Purpose

Power amplifiers (PAs) play an important role in wireless communications because they dominate system performance. High-linearity broadband PAs are of great value for potential use in multi-band system implementation. The purpose of this paper is to present a cascode power amplifier architecture to achieve high power and high efficiency requirements for 4.2∼5.4 GHz applications.

Design/methodology/approach

A common emitter (CE) configuration with a stacked common base configuration of heterojunction bipolar transistor (HBT) is used to achieve high power. T-type matching network is used as input matching network. To increase the bandwidth, the output matching networks are implemented using the two L-networks.

Findings

By using the proposed method, the stacked PA demonstrates a maximum saturated output power of 26.2 dBm, a compact chip size of 1.17 × 0.59 mm2 and a maximum power-added efficiency of 46.3 per cent. The PA shows a wideband small signal gain with less than 3 dB variation over working frequency. The saturated output power of the proposed PA is higher than 25 dBm between 4.2 and 5.4 GHz.

Originality/value

The technology adopted for the design of the 4.2-to-5.4 GHz stacked PA is the 2-µm gallium arsenide HBT process. Based on the proposed method, a better power performance of 3 dB improvement can be achieved as compared with the conventional CE or common-source amplifier because of high output stacking impedance.

Details

Circuit World, vol. 46 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 April 2003

Georgios I. Zekos

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination of some…

88455

Abstract

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination of some legal aspects concerning MNEs, cyberspace and e‐commerce as the means of expression of the digital economy. The whole effort of the author is focused on the examination of various aspects of MNEs and their impact upon globalisation and vice versa and how and if we are moving towards a global digital economy.

Details

Managerial Law, vol. 45 no. 1/2
Type: Research Article
ISSN: 0309-0558

Keywords

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