Konstantinos Stamoulis, Stelios K. Georgantzinos and G.I. Giannopoulos
The present study deals with the numerical modeling of the low-velocity impact damage of laminated composites which have increasingly important applications in aerospace primary…
Abstract
Purpose
The present study deals with the numerical modeling of the low-velocity impact damage of laminated composites which have increasingly important applications in aerospace primary structures. Such damage, generated by various sources during ground handling, substantially reduces the mechanical residual performance and the safe-service life. The purpose of this paper is to present and validate a computationally efficient approach in order to explore the effect of critical parameters on the impact damage characteristics.
Design/methodology/approach
Numerical modeling is considered as one of the most efficient tool as compared to the expensive and time-consuming experimental testing. In this paper, a finite element model based on explicit dynamics formulations is adopted. Hashin criterion is applied to predict the intralaminar damage initiation and evolution. The numerical analysis is performed using the ABAQUS® programme.
Findings
The employed modeling approach is validated using corresponding numerical data found in the literature and the presented results show a reasonable correlation to the available literature data. It is demonstrated that the current model can be used to capture the force-time response as well as damage parameter maps showing the intralaminar damage evolution for different impact cases with respect to the physical boundary conditions and a range of impact energies.
Originality/value
Low-velocity impact damage of laminated composites is still not well understood due to the complexity and non-linearity of the damage zone. The presented model is used to predict the force-time response which is considered as one of the most important parameters influencing the structural integrity. Furthermore, it is used for capturing the damage shape evolution, exhibiting a high degree of capability as a damage assessment computational tool.
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Maria Papanikou, Utku Kale, András Nagy and Konstantinos Stamoulis
This study aims to identify variability in aviation operators in order to gain greater understanding of the changes in aviation professional groups. Research has commonly…
Abstract
Purpose
This study aims to identify variability in aviation operators in order to gain greater understanding of the changes in aviation professional groups. Research has commonly addressed human factors and automation in broad categories according to a group’s function (e.g., pilots, air traffic controllers [ATCOs], engineers). Accordingly, pilots and Air Traffic Controls (ATCOs) have been treated as homogeneous groups with a set of characteristics. Currently, critical themes of human performance in light of systems’ developments place the emphasis on quality training for improved situational awareness (SA), decision-making and cognitive load.
Design/methodology/approach
As key solutions centre on the increased understanding and preparedness of operators through quality training, the authors deploy an iterative mixed methodology to reveal generational changes of pilots and ATCOs. In total, 46 participants were included in the qualitative instrument and 70 in the quantitative one. Preceding their triangulation, the qualitative data were analysed using NVivo and the quantitative analysis was aided through descriptive statistics.
Findings
The results show that there is a generational gap between old and new generations of operators. Although positive views on advanced systems are being expressed, concerns about cognitive capabilities in the new systems, training and skills gaps, workload and role implications are presented.
Practical implications
The practical implications of this study extend to different profiles of operators that collaborate either directly or indirectly and that are critical to aviation safety. Specific implications are targeted on automation complacency, bias and managing information load, and training aspects where quality training can be aided by better understanding the occupational transitions under advanced systems.
Originality/value
In this paper, the authors aimed to understand the changing nature of the operators’ profession within the advanced technological context, and the perceptions and performance-shaping factors of pilots and ATCOs to define the generational changes.
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K. Stamoulis and A.E. Giannakopoulos
As the dimensions of structures are scaled down to the micro‐ and nano‐domains, the mechanical behavior becomes size dependent and thus, the classical elasticity solutions cannot…
Abstract
Purpose
As the dimensions of structures are scaled down to the micro‐ and nano‐domains, the mechanical behavior becomes size dependent and thus, the classical elasticity solutions cannot be expected to hold. In particular, recent experimental investigations of fatigue strength of metals show pronounced strengthening due to the influences of both grain size and small geometrical dimensions. This paper aims to provide a simple, yet rigorous analytical model in order to address the aforementioned size effects.
Design/methodology/approach
The present study employs a framework based on the type II, strain gradient elasticity theory by Mindlin, embedded into a thermodynamics‐based formulation which considers both mechanical behavior parameters and material lengths, as internal variables, in order to model metal fatigue.
Findings
A thermodynamics‐based, second gradient elasto‐plastic formulation with an explicit material length, which captures the size effects in fatigue of small‐scale metal components, has been established. From a physical viewpoint, the evolution of the internal length in the constitutive equations with the evolution of the intrinsic wavelength (e.g. persistent slip bands spacing) can be identified signifying the splitting of the grains into sub‐regions and consequently, the softening of the material.
Originality/value
The major novelty of the proposed modeling is that the internal characteristic length considered is not a fixed parameter, but evolves with the plastic effective strain amplitude obtained from cyclic loading.
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Francis Lwesya and Justine Mbukwa
The aim of this article was to present a retrospective assessment of the intellectual structure of private agricultural and food standards research in global trade. This study was…
Abstract
Purpose
The aim of this article was to present a retrospective assessment of the intellectual structure of private agricultural and food standards research in global trade. This study was motivated by the increasing role of standards and certifications in governing global agricultural and food trade.
Design/methodology/approach
The current investigation was carried out with bibliometric methods using VOSviewer software. Techniques such as citation, co-citation, keyword co-occurrence, keyword evolution and co-authorship analyses were performed to tackle the research questions. Articles were extracted from Scopus database for the period 1998–2022 (30th August 2022) with selected keywords (“Private food standard*” OR “food standard*” OR “agri-food standard*” AND “agri*” OR “agro*” OR “farm*” OR “food*” AND “international trade” OR “global trade” OR “international business”) along certain filters (subject – Economics and Business management: language – English: Document – article and review articles and source – journals).
Findings
The results show that the intellectual structure of private agricultural and food standards research in global trade has evolved around five clusters, namely: (1) the political economy of food standards, (2) food standards and their challenges in global trade, (3) food standards and integration into value chains, (4) food standards and market access and (5) food standards and exports from developing countries. However, the authors found the research gaps in each of the thematic clusters.
Research limitations/implications
The main limitation of this study is that the authors focused their attention on certain aspects of bibliometric review, such as the intellectual structure of the field, the citation analysis and the collaboration network. Future research could attempt to explore new field development through bibliographic coupling and deepening of conceptual structure using content analysis by incorporating the research methods used in the respective studies.
Practical implications
The emerging research areas in private agricultural and food standards in global trade are related to topics on food quality, sustainable development, genetically modified organisms, World Trade Organization, tariff structure, trade agreements, food industry and European Union. However, there is less research and little collaboration between Africa and developed countries. For example, Africa's total publications were (15), while the US had (46), China (15), Belgium (23), Germany (27), Italy (32) and the UK (24).
Originality/value
There are limited studies that have conducted a retrospective evaluation of the intellectual structure of private agricultural and food standards research in the global trade using bibliometric analysis. The present investigation is novel in identifying the thematic research clusters, emerging issues and future research directions. This is more important to developing countries as their agricultural produce face challenges to access markets of the developed world.
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Gianluca Brunori, Tessa Avermaete, Fabio Bartolini, Natalia Brzezina, Terry Marsden, Erik Mathijs, Ana Moragues-Faus and Roberta Sonnino
To analyze more deeply and in a systemic perspective food system outcomes, and the contribution that small farming can give to the achievement of those outcomes, a detailed…
Abstract
To analyze more deeply and in a systemic perspective food system outcomes, and the contribution that small farming can give to the achievement of those outcomes, a detailed analysis of food systems is required, which highlights its components, activities and dynamics. Thus, this chapter deepens the analysis of the food system. We first reflect on the complexity of the concept of food system, discussing the abundance of different conceptualizations proposed in the scientific and political debate on the base of different disciplines and perspectives. Then, a comprehensive representation is shown, which is then unpacked. The food system actors, assets and functions are explored, with an eye on power relations among actors and on the main drivers of change. Governance (that also includes actors external to the food systems) is called ‘reflexive’, as long as it characterizes a system that is able to reflect upon the conditions and the forms of its own functioning, to detect and analyze threats and to change accordingly, with the involvement of actors external to the food systems. This analysis, which represents the focus of this section, provides the base for the description of the food system vulnerability developed in Chapter 4. Drivers of change and governance emerge as key categories to consider.
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Dina Modestus Nziku and John Struthers
Rural farm and non-farm based entrepreneurial activities within Sub-Saharan Africa (SSA) play significant roles in job creation as well as food security for the majority of rural…
Abstract
Rural farm and non-farm based entrepreneurial activities within Sub-Saharan Africa (SSA) play significant roles in job creation as well as food security for the majority of rural dwelling citizens (UNCTAD, 2018). This chapter examines the policies and strategies for supporting both farm and non-farm entrepreneurial activities within rural communities in SSA. In order to achieve this, the authors have completed a systematic literature review of both conceptual and empirical work on the role of policies and strategies for rural entrepreneurship in selected SSA, namely Ethiopia, Rwanda, Sierra Leone, and the United Republic of Tanzania (URT). This was completed alongside an assessment of the constraints and potential opportunities in order to stimulate linkages between rural entrepreneurship and structural economic transformation including the potential roles of both farm and non-farm based entrepreneurial activities. Key linkages between rural farm and non-farm based entrepreneurial activities are emphasised The chapter also highlights mechanisms through which governments and private sectors can work together for the maximisation of available opportunities and best practices that rural entrepreneurship can offer for job creation among rural communities in SSA.
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Cherise Addinsall, Norah Rihai and Antoinette Nasse
The predominate Western approach applied to agricultural research and development in Vanuatu is to focus on sector-specific or crop-by crop basis that is universally applied…
Abstract
The predominate Western approach applied to agricultural research and development in Vanuatu is to focus on sector-specific or crop-by crop basis that is universally applied rather than designing context-specific research objectives. The findings from a gender livelihoods analysis conducted with 45 households in East Coast Santo, Vanuatu show that this sectorial focus inherently excludes women. Female smallholder livelihood activities were found to be centred around activities within the informal economy (traditional economy) and agricultural input is focused on harvesting of Non-timber Forest Products (NTFPs) and food crops for subsistence and local markets, while male smallholder farmers generally focus on cash crops and the formal commercial sector.
The strategies put forward by the Declaration of the International Forum for Agroecology, Nyeleni, Mali, 2007, recognise the central role of women in rural development, and align closely with the traditional economy and the political, economic and social foundations of Vanuatu. Therefore, it is recommended that research and development projects operating in this space consider the integration of agroecology and sustainable livelihoods into their project designs through frameworks such as the Agroecology and Sustainable Livelihoods Framework (ASRLF). The ASRLF approaches research through a critical lens that challenges and transforms structures of power in society and sees minority groups (such as women and youth) and their knowledge, values, vision and leadership as critical for moving forward. This chapter demonstrates the application of the ASRLF to a gender livelihoods analysis and the development of a strategy to engage and empower rural farming women.
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Napoleon Kurantin and Bertha Z. Osei-Hwedie
This chapter uses the Ghana Living Standards Survey (GLSS) 7 datasets to investigate and examine the effect of rural non-farm diversification and its implications on agricultural…
Abstract
This chapter uses the Ghana Living Standards Survey (GLSS) 7 datasets to investigate and examine the effect of rural non-farm diversification and its implications on agricultural (tree-crop) farming sector inequalities and sustainable development in Ghana. Applying a Gini-decomposition method and/or technique within a quantitative approach, the study outcome indicates the average non-farm income thus, increased income inequality among tree-crop smallholder rural livelihoods and households. Income diversification by farm households has gained the attention of governments, policy makers, and researchers because of its commonness and contribution to socio-economic development especially in developing countries. Aggregationally, non-farm self-employment reduced income inequality, and non-farm wage employment income led to an increase in income inequality. Increased rate of educational enrollment and achievement is the most important variable of non-farm income inequality. Government effort at expanding tree-crop acreages and improve yields have to degree achieved its intended policy implementation, increased rate of educational achievement could undermine the socio-economic policy cohesion and sustainable development of rural livelihood, communities, and national economy. Tree crop policies should take account of the spatial distribution of tree-crop commodity production and in particular, the implication and effect of rural non-farm diversification on agricultural sector inequalities.
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Ifeoluwa Damilola Adeoye, Wayo Seini, Daniel Sarpong and Ditchfield Amegashie
The purpose of this paper is to analyze the effect of the different components of off-farm income on multi-dimensional poverty. Furthermore, the study aims to measure…
Abstract
Purpose
The purpose of this paper is to analyze the effect of the different components of off-farm income on multi-dimensional poverty. Furthermore, the study aims to measure multi-dimensional poverty and also identify the determinants of multi-dimensional poverty in Nigeria. The paper reveals the different contributions of the dimensions of education, health and living standard.
Design/methodology/approach
The study focuses on rural farm households in Nigeria. Data are obtained from the Nigeria General Household Survey, 2013. The survey covers both urban and rural areas of the 36 states of Nigeria. Owing to the interest of this study in the rural farm household’s sub-sector, a nationally representative sample of 836 rural farm households are selected for the study after the data merging process. Rural farm households in this paper earn 50 percent of their total income from crop and livestock production. The paper employs the Multi-dimensional Poverty Index (MPI) to measure multi-dimensional poverty across the six different geographical zones of Nigeria. The probit regression model is used to estimate and analyze the effect of off-farm income components on multi-dimensional poverty and also to identify the determinants of multi-dimensional poverty.
Findings
The results of the study show that among the off-farm income components, the non-farm wage income and non-farm self-employment income have negative association with multi-dimensional poverty. Findings show that multi-dimensional poverty is high in Nigeria with deprivations in health contributing the most. Northern Regions have a higher estimate. Results reveal that sex, age, number of adults, formal credit access, access to extension services and location characteristics are key determinants of multi-dimensional poverty. The MPI for Nigeria averaged 47 percent. Across regions, deprivation in the health dimension contributes about 44 percent to multi-dimensional poverty. Deprivation in living standards contributes 40.5 percent, while deprivation in education contributes 15.5 percent to multi-dimensional poverty.
Research limitations/implications
Due to the nature of the data used, the health indicators (nutrition and child mortality) are absent but proxies are used instead. Future research could introduce gender dimensions.
Practical implications
Improving the involvement of rural farm households in non-farm self-employment sector could improve their livelihoods and prevent migration to urban centers, especially among the youths.
Social implications
Improving the quality of health, education and living standards will lead to lower poverty levels in Nigeria. Farmers can best reduce their multi-dimensional poverty by engaging in more off-farm jobs.
Originality/value
This paper provides information to policy makers on the effect of different components of income from the off-farm sector on multi-dimensional poverty alongside with the determinants of multi-dimensional poverty at a national level for the rural farm households. By using MPI, the contribution of the different dimensions used in computing the MPI across the six geographical regions within the country is revealed. This provides policy makers with more information for development purposes.