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Article
Publication date: 13 April 2023

Edson Mbedzi and Forget Mingiri Kapingura

Infrastructure deficiency and supply disruption challenges are quite common among developing economies. While Sub-Saharan Africa is not unique to these challenges, it is the…

Abstract

Purpose

Infrastructure deficiency and supply disruption challenges are quite common among developing economies. While Sub-Saharan Africa is not unique to these challenges, it is the extent of levels of infrastructure deficiency and disruptions that affect the level of performance of small businesses. Literature on the performance of small businesses suggests both infrastructure availability and disruptions affect the performance of small businesses, but the effects on informal enterprises that operate from locations where the supply of infrastructure is weak are less documented. The paper, therefore, investigates the effects of four types of infrastructure supply in two dimensions of availability and disruption levels on the performance of informal enterprises in 12 Sub-Saharan African countries.

Design/methodology/approach

The study uses data from World Bank informal enterprises surveys based on a sample of 3 735 informal enterprises. The study uses the multiple analysis of variance method based on the World Bank's Informal Enterprise Surveys (IFS) country-level cross-sectional data collected between 2009 and 2019.

Findings

Results show infrastructure supply is quite low irrespective of the form of infrastructure. Infrastructure availability is associated with high supply disruptions. Infrastructure supply deficiency and disruption intensities are negatively associated with informal enterprises' performance. Finally, the effects of both infrastructure availability and supply disruptions are positively associated with informal enterprises' business activity levels.

Research limitations/implications

Due to data limitations, only four types of infrastructure are captured in the analysis. A wider variety of types of infrastructure could improve the analysis.

Originality/value

Given the deficiency level of infrastructure and its implications on informal enterprise development, therefore, policy interventions aiming at addressing informal enterprises' challenges should focus on improving infrastructure supply deficiencies and disruption challenges. This paper provides the link between infrastructure levels, infrastructure supply disruptions and performance of the informal enterprises which is an essential starting point for policy intervention in informal enterprise development.

Details

African Journal of Economic and Management Studies, vol. 14 no. 4
Type: Research Article
ISSN: 2040-0705

Keywords

Article
Publication date: 10 May 2022

Augustine Senanu Komla Kukah, De-Graft Owusu-Manu, Edward Badu and David John Edwards

This study aims to evaluate the key risk factors inherent in public–private partnership (PPP) power projects in Ghana and further determine the critical risk factors affecting…

Abstract

Purpose

This study aims to evaluate the key risk factors inherent in public–private partnership (PPP) power projects in Ghana and further determine the critical risk factors affecting both the public and private sectors in PPP power projects.

Design/methodology/approach

Ranking-type Delphi survey in two rounds was conducted to establish a comprehensive list of critical risk factors of PPP. Purposive and snowball sampling techniques helped obtain experts for the Delphi survey. Mean score ranking, factor analysis, Cronbach α coefficient and Kendall’s concordance were used for analysis. The probability of occurrence and severity of each risk factor were computed to obtain the risk impact.

Findings

From the list of 67 risks, 37 risk factors were deemed to be critical. The five topmost risk factors were: delay payment on contract, private investor change, political risks, fluctuating demand of power generated and public opposition. Principal component analysis grouped the risk factors into seven major themes.

Originality/value

This study develops an authoritative risk factor list for PPP power projects, which reflects both sector and country conditions for prioritizing and mitigating risk factors. Delphi approach adopted in this study can be used by future studies in similar environments where PPP is novel and expert respondents scarce.

Details

Journal of Facilities Management , vol. 22 no. 1
Type: Research Article
ISSN: 1472-5967

Keywords

Article
Publication date: 29 October 2021

Kurt A. Wurthmann

This study aims to provide a new method for precisely sizing photovoltaic (PV) arrays for standalone, direct pumping PV Water Pumping (PVWP) systems for irrigation purposes.

Abstract

Purpose

This study aims to provide a new method for precisely sizing photovoltaic (PV) arrays for standalone, direct pumping PV Water Pumping (PVWP) systems for irrigation purposes.

Design/methodology/approach

The method uses historical weather data and considers daily variability in regional temperatures and rainfall, crop evapotranspiration rates and seasonality effects, all within a nonparametric bootstrapping approach to synthetically generate daily rainfall and crop irrigation needs. These needs define the required daily supply of pumped water to achieve a user-specified level of reliability, which provides the input to an intuitive approach for PV array sizing. An economic comparison of the costs for the PVWP versus a comparably powered diesel generator system is provided.

Findings

Pumping 22.8646 m³/day of water would meet the pasture crop irrigation needs on a one-acre (4046.78 m²) tract of land in South Florida, with 99.9% reliability. Given the specified assumptions, an 8.4834 m² PV array, having a peak power of 1.1877 (kW), could provide the 1.2347 (kWh/day) of hydraulic energy needed to supply this volume over a total head of 20 meters. The PVWP system is the low-cost option when diesel prices are above $0.90/liter and total installed PV array costs are fixed at $2.00/Watt peak power or total installed PV array costs are below $1.50/Watt peak power and diesel prices are fixed at $0.65/liter.

Originality/value

Because the approach is not dependent on the shapes of the sampling distributions for regional climate factors and can be adapted to consider different types of crops, it is highly portable and applicable for precisely determining array sizes for standalone, direct pumping PVWP systems for irrigating diverse crop types in diverse regions.

Details

Journal of Engineering, Design and Technology , vol. 21 no. 6
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 30 March 2022

Karthick R., Ramakrishnan C. and Sridhar S.

This paper aims to introduce the quasi impedance source inverter (qZSI)-based static compensator (STATCOM), which is incorporated into the hybrid distributed power generation…

Abstract

Purpose

This paper aims to introduce the quasi impedance source inverter (qZSI)-based static compensator (STATCOM), which is incorporated into the hybrid distributed power generation system for enhancement of power quality. The distributed power generation system includes the photovoltaic (PV), wind energy conversion system (WECS) and battery energy storage system.

Design/methodology/approach

The WECS is used by the self-excited induction generator (SEIG) and the flywheel energy storage system (FESS). To regulate its terminal voltage and frequency, the SEIG requires adjustable volt-ampere reactive (VAR). A combination of a STATCOM and a fixed condenser bank usually serves to satisfy the VAR demand. The maximum correntropy criterion-based adaptive filter technique (AFT) is proposed to control the qZSI-STATCOM and to guarantee that the voltage at the SEIG terminal is harmonic-free while providing non-linear three-phase and single-phase loads.

Findings

The coordinated operation of the suggested voltage control and flywheel control systems ensures that load voltage and frequency are retained in their respective values at very low harmonic distortions regardless of wind speed and load variation. The simulation and experimental studies are carried out under different load conditions to validate the efficiencies of the PV-assisted STATCOM.

Originality/value

To improve system stability and minimize total costs, extra load current sensors can also be avoided. This paper proposes to control the SEIG terminal voltage and harmonic elimination in the standalone WECS systems using maximum correntropy criterion-based AFT with a fuzzy logic controller.

Article
Publication date: 29 March 2021

Roohie Kaushik, Jasdeep Kaur and Anushree

Reference voltage or current generators are an important requirement for an analog or digital circuit design. Bandgap reference circuits (BGR) are most common way of generating…

619

Abstract

Purpose

Reference voltage or current generators are an important requirement for an analog or digital circuit design. Bandgap reference circuits (BGR) are most common way of generating the reference voltage. This paper aims to provide a detailed insight of design of a folded cascode operational amplifier (FC op amp) and a BGR circuit. The complete study flow from design to layout of the circuits on 180 nm semiconductor laboratory (SCL) process leading to bonding diagram for possible tape-out is discussed. This study work has been supported by MeitY, Govt. of India, through Special Manpower Development Project Chip to System Design.

Design/methodology/approach

This paper provides a detailed insight in design of a FC op amp and a BGR circuit. The complete study flow from design to layout of the two circuits on 180 nm SCL process leading to bonding diagram for possible tape-out is discussed. Section 2 shows the design of FC op amp, beta-multiplier circuit and their simulation results. Section 3 describes the comparison of design of conventional BGR and the proposed BGR with other state-of-art BGR circuits. Section 4 gives the comparison of their performance. The conclusion is given in Section 5.

Findings

The post-layout simulation of FC op amp show an open-loop gain of 64.5 dB, 3-dB frequency of 5.5 KHz, unity-gain bandwidth of 8.7 MHz, slew rate of 8.4 V/µs, CMRR of 111 dB and power of 25.5µW. Among the two BGR designs, the conventional BGR generated 693 mV of reference voltage with a temperature coefficient of 16 ppm/°C the other BGR, with curvature correction generated 1.3 V of reference voltage with a temperate coefficient of 6.3 ppm/°C , both results in temperature ranging from −40°C to 125°C. The chip layout of the circuits designed on 180 nm SCL process ensures design rule check (DRC), Antenna and layout versus schematic (LVS) clean with metal fill.

Research limitations/implications

Slew rate, stability analysis, power are important parameters which should be taken care while designing an op amp for a BGR. Direct current gain should be kept higher to reduce offset errors. Input common mode range is decided by the operating temperature range. A higher power supply rejection ratio will reduce BGR sensitivity to supply voltage variations. Input offset should be kept low to reduce BGR error in reference voltage. However, this paper emphasis on the flow from schematic to layout using simulation tools. As part of the study, the bonding diagram for tape-out of BGR and FC design in the given SCL frame size with seal ring is also explored, for possible tape-out.

Practical implications

Reference voltage or current generators are an important requirement for an analog or digital circuit design. BGR are most common way of generating the reference voltage. This paper provides a detailed insight in design of a FC op amp and a BGR circuit. The complete study flow from design to layout of the circuits on 180 nm SCL process leading to bonding diagram for possible tape-out is discussed. The chip layout of the circuits was designed on 180 nm SCL process ensuring DRC, antenna and LVS clean with metal fill using Cadence virtuoso and Mentor Graphics Calibre simulation tools.

Social implications

BGR are most common way of generating the reference voltage. This paper gives a detailed insight of a BGR design using a folded-cascode operational amplifier. The FC op amp is biased using a beta multiplier circuit and high-swing cascode current mirror circuit. The paper discuss FC circuit design flow from schematic to layout.

Originality/value

FC op amp is biased using a beta multiplier circuit and high-swing cascode current mirror. The paper discusses FC design flow from schematic to layout. The circuits were designed on 180 nm SCL technology with 1.8 V of power supply. The post-layout simulation show an open-loop gain of 64.5 dB, 3 dB frequency of 5.5 KHz, unity-gain bandwidth of 8.7 MHz, slew rate of 8.4 V/µs, CMRR of 111 dB and power of 25.5 µW. BGR were designed using FC op amp. The proposed BGR generated 1.3 V of reference voltage with a temperature coefficient of 6.3 ppm/°C in the range from −40°C to 125°C in schematic simulation.

Details

Circuit World, vol. 50 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 18 March 2024

Evaristo Haulle and Gabriel Kanuti Ndimbo

Tanzania is rich in small hydropower (SHP) potentials. However, many of these potentials have yet to be fully used, and more than two-thirds of its rural population lacks access…

Abstract

Purpose

Tanzania is rich in small hydropower (SHP) potentials. However, many of these potentials have yet to be fully used, and more than two-thirds of its rural population lacks access to electricity. The purpose of this paper is to explore the role of SHP stations in improving rural welfare in the southern highlands of Tanzania. It further explores the history, cost-effective analysis and threats to the sustainability of SHP as one of the renewable energy sources.

Design/methodology/approach

The study uses a qualitative research design to explore respondents’ views on the role of SHP stations in facilitating rural electrification and welfare improvement. Primary data were gathered using semi-structured interviews with the 27 key informants and beneficiaries of SHP stations from the Southern Highlands of Tanzania. In addition, the study used documentary research to complement the information from the field survey.

Findings

The findings found that SHP stations enhance rural electrification and welfare by providing electricity in remote areas with sparse populations. They operate as standalone off-grids, often by church communities and individuals. However, the sustainability of SHP stations is hampered by challenges such as climate change impacts, high capital investment costs, heavy siltation of small reservoirs, skilled manpower shortages, limited local manufacturing capabilities and infrastructural issues.

Originality/value

The study contributes to the ongoing debate on renewable energy supply and uses, focusing on how SHP stations could contribute to sustainable rural electrification and achieve the 2030 United Nations agenda for sustainable development, which, among other things, aims to safeguard access to sustainable and modern energy and alleviate energy poverty.

Details

International Journal of Development Issues, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1446-8956

Keywords

Article
Publication date: 19 February 2024

Xiang Shen, Kai Zeng, Liming Yang, Chengyong Zhu and Laurent Dala

This paper aims to study passive control techniques for transonic flow over a backward-facing step (BFS) using square-lobed trailing edges. The study investigates the efficacy of…

Abstract

Purpose

This paper aims to study passive control techniques for transonic flow over a backward-facing step (BFS) using square-lobed trailing edges. The study investigates the efficacy of upward and downward lobe patterns, different lobe widths and deflection angles on flow separation, aiming for a deeper understanding of the flow physics behind the passive flow control system.

Design/methodology/approach

Large Eddy Simulation and Reynolds-averaged Navier–Stokes were used to evaluate the results of the study. The research explores the impact of upward and downward patterns of lobes on flow separation through the effects of different lobe widths and deflection angles. Numerical methods are used to analyse the behaviour of transonic flow over BFS and compared it to existing experimental results.

Findings

The square-lobed trailing edges significantly enhance the reduction of mean reattachment length by up to 80%. At Ma = 0.8, the up-downward configuration demonstrates increased effectiveness in reducing the root mean square of pressure fluctuations at a proximity of 5-step height in the wake region, with a reduction of 50%, while the flat-downward configuration proves to be more efficient in reducing the root mean square of pressure fluctuations at a proximity of 1-step height in the near wake region, achieving a reduction of 71%. Furthermore, the study shows that the up-downward configuration triggers early spanwise velocity fluctuations, whereas the standalone flat-downward configuration displays less intense crosswise velocity fluctuations within the wake region.

Practical implications

The findings demonstrate the effectiveness of square-lobed trailing edges as passive control techniques, showing significant implications for improving efficiency, performance and safety of the design in aerospace and industrial systems.

Originality/value

This paper demonstrates that the square-lobed trailing edges are effective in reducing the mean reattachment length and pressure fluctuations in transonic conditions. The study evaluates the efficacy of different configurations, deflection angles and lobe widths on flow and provides insights into the flow physics of passive flow control systems.

Details

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

Keywords

Book part
Publication date: 14 March 2024

Mousumi Bose, Lilly Ye and Yiming Zhuang

Today's marketing is dominated by decision-making based on artificial intelligence and machine learning. This study focuses on one semi- and unsupervised machine learning…

Abstract

Today's marketing is dominated by decision-making based on artificial intelligence and machine learning. This study focuses on one semi- and unsupervised machine learning technique, generative adversarial networks (GANs). GANs are a type of deep learning architecture capable of generating new data similar to the training data that were used to train it, and thus, it is designed to learn a generative model that can produce new samples. GANs have been used in multiple marketing areas, especially in creating images and video and providing customized consumer contents. Through providing a holistic picture of GANs, including its advantage, disadvantage, ethical considerations, and its current application, the study attempts to provide business some strategical orientations, including formulating strong marketing positioning, creating consumer lifetime values, and delivering desired marketing tactics in product, promotion, pricing, and distribution channel. Through using GANs, marketers will create unique experiences for consumers, build strategic focus, and gain competitive advantages. This study is an original endeavor in discussing GANs in marketing, offering fresh insights in this research topic.

Details

The Impact of Digitalization on Current Marketing Strategies
Type: Book
ISBN: 978-1-83753-686-3

Keywords

Article
Publication date: 9 October 2023

Gokulnath R. and Booma Devi

Diesel has traditionally been considered the best-suited and most widely used fuel in various sectors, including manufacturing industries, power production, automobiles and…

Abstract

Purpose

Diesel has traditionally been considered the best-suited and most widely used fuel in various sectors, including manufacturing industries, power production, automobiles and transportation. However, with the ongoing crisis of fossil fuel inadequacy, the search for alternative fuels and their application in these sectors has become increasingly important. One particularly interesting and beneficial alternative fuel is biodiesel derived from bio sources.

Design/methodology/approach

In this research, an attempt was made to use biodiesel in an unconventional micro gas turbine engine. It will remove the concentric use of diesel engines for power production by improving fuel efficiency as well as increasing the power production rate. Before the fuel is used enormously, it has to be checked in many ways such as performance, emission and combustion analysis experimentally.

Findings

In this paper, a detailed experimental study was made for the use of Spirulina microalgae biodiesel in a micro gas turbine. A small-scale setup with the primary micro gas turbine and secondary instruments such as a data acquisition system and AVL gas analyser. The reason for selecting the third-generation microalgae is due to its high lipid and biodiesel production rate. For the conduction of experimental tests, certain conditions were followed in addition that the engine rotating rpm was varied from 4,000, 5,000 and 6,000 rpm. The favourable and predicted results were obtained with the use of microalgae biodiesel.

Originality/value

The performance and combustion results were not exactly equal or greater for biodiesel blends but close to the values of pure diesel; however, the reduction in the emission of CO was at the appreciable level for the used spirulina microalgae biodiesel. The emission of nitrogen oxides and carbon dioxide was a little higher than the use of pure diesel. This experimental analysis results proved that the use of spirulina microalgae biodiesel is both economical and effective replacement for fossil fuel.

Details

Aircraft Engineering and Aerospace Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 8 June 2022

Chinnaraj Gnanavel and Kumarasamy Vanchinathan

These implementations not only generate excessive voltage levels to enhance the quality of power but also include a detailed investigating of the various modulation methods and…

Abstract

Purpose

These implementations not only generate excessive voltage levels to enhance the quality of power but also include a detailed investigating of the various modulation methods and control schemes for multilevel inverter (MLI) topologies. Reduced harmonic modulation technology is used to produce 11-level output voltage with the production of renewable energy applications. The simulation is done in the MATLAB/Simulink for 11-level symmetric MLI and is correlated with the conventional inverter design.

Design/methodology/approach

This paper is focused on investigating the different types of asymmetric, symmetric and hybrid topologies and control methods used for the modular multilevel inverter (MMI) operation. Classical MLI configurations are affected by performance issues such as poor power quality, uneconomic structure and low efficiency.

Findings

The variations in both carrier and reference signals and their performance are analyzed for the proposed inverter topologies. The simulation result compares unipolar and bipolar pulse-width modulation (PWM) techniques with total harmonic distortion (THD) results. The solar-fed 11-level MMI is controlled using various modulation strategies, which are connected to marine emergency lighting loads. Various modulation techniques are used to control the solar-fed 11-level MMI, which is connected to marine emergency lighting loads. The entire hardware system is controlled by using SPARTAN 3A field programmable gate array (FPGA) board and the least harmonics are obtained by improving the power quality.

Originality/value

The simulation result compares unipolar and bipolar PWM techniques with THD results. Various modulation techniques are used to control the solar-fed 11-level MMI, which is connected to marine emergency lighting loads. The entire hardware system is controlled by a SPARTAN 3A field programmable gate array (FPGA) board, and the power quality is improved to achieve the lowest harmonics possible.

Details

Circuit World, vol. 49 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

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