Isaac Ferreira, Carolina Melo, Rui Neto, Margarida Machado, Jorge Lino Alves and Sacha Mould
The purpose of this study is to evaluate and compare the mechanical performance of FFF parts when subjected to post processing thermal treatment. Therefore, a study of the…
Abstract
Purpose
The purpose of this study is to evaluate and compare the mechanical performance of FFF parts when subjected to post processing thermal treatment. Therefore, a study of the annealing treatment influence on the mechanical properties was performed. For this, two different types of Nylon (PA12) were used, FX256 and CF15, being the second a short fibre reinforcement version of the first one.
Design/methodology/approach
In this study, tensile and flexural properties of specimens produced via FFF were determined after being annealed at temperatures of 135°C, 150°C or 165°C during 3, 6, 12 or 18 h and compared with the non-treated conditions. Differential scanning calorimetry (DSC) was performed to determine the degree of crystallinity. To evaluate the annealing parameters’ influence on the mechanical properties, a full factorial design of experiments was developed, followed by an analysis of variance, as well as post hoc comparisons, to determine the most significative intervening factors and their effect on the results.
Findings
The results indicate that CF15 increased its tensile modulus, strength, flexural modulus and flexural strength around 11%, while FX256 presented similar values for tensile properties, doubling for flexural results. Flexural strain presented an improvement, indicating an increased interlayer behaviour. Concerning to the DSC analysis, an increase in the degree of crystallinity for all the annealed parts.
Originality/value
Overall, the annealing treatment process cause a significant improvement in the mechanical performance of the material, with the exception of 165°C annealed specimens, in which a decrease of the mechanical properties was observed, resultant of material degradation.
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Bruno Benevit, Carolina Silva da Trindade, Roberto Bezerra de Melo Junior, Daniel de Abreu Pereira Uhr and Julia Gallego Ziero Uhr
This study aims to evaluate the effects of the synergy between monitoring technologies and deforestation control policies promoted by the Action Plan for the Prevention and…
Abstract
Purpose
This study aims to evaluate the effects of the synergy between monitoring technologies and deforestation control policies promoted by the Action Plan for the Prevention and Control of Deforestation in the Legal Amazon (PPCDAm) during its initial stage.
Design/methodology/approach
The triple difference method is employed to explore the differences between the non-metropolitan municipalities with Indigenous lands and other regional municipalities.
Findings
The findings indicate a reduction of approximately 16.1 km² per municipality between 2004 and 2007. This reduction corresponds to a decrease of 10,293 km² in the area of deforestation and a total of 498 million tons of CO2. To ensure the robustness of the results, placebo tests, event study and flexibility in the composition of the groups were conducted. The robustness tests substantiate the findings.
Practical implications
These results emphasize the significance of remote monitoring policies for controlling deforestation in isolated regions and Indigenous lands. Additionally, such results indicate that the policy was cost-effective.
Originality/value
This study innovates by examining the causal impact of the initial phase of the PPCDAm before 2008, a period not focused on existing literature. Further, employing the triple difference method innovates methodologically to assess PPCDAm's effect on deforestation in isolated Amazon areas.
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Xiaojie Xu and Yun Zhang
Forecasts of commodity prices are vital issues to market participants and policy makers. Those of corn are of no exception, considering its strategic importance. In the present…
Abstract
Purpose
Forecasts of commodity prices are vital issues to market participants and policy makers. Those of corn are of no exception, considering its strategic importance. In the present study, the authors assess the forecast problem for the weekly wholesale price index of yellow corn in China during January 1, 2010–January 10, 2020 period.
Design/methodology/approach
The authors employ the nonlinear auto-regressive neural network as the forecast tool and evaluate forecast performance of different model settings over algorithms, delays, hidden neurons and data splitting ratios in arriving at the final model.
Findings
The final model is relatively simple and leads to accurate and stable results. Particularly, it generates relative root mean square errors of 1.05%, 1.08% and 1.03% for training, validation and testing, respectively.
Originality/value
Through the analysis, the study shows usefulness of the neural network technique for commodity price forecasts. The results might serve as technical forecasts on a standalone basis or be combined with other fundamental forecasts for perspectives of price trends and corresponding policy analysis.
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Bingzi Jin and Xiaojie Xu
Agriculture commodity price forecasts have long been important for a variety of market players. The study we conducted aims to address this difficulty by examining the weekly…
Abstract
Purpose
Agriculture commodity price forecasts have long been important for a variety of market players. The study we conducted aims to address this difficulty by examining the weekly wholesale price index of green grams in the Chinese market. The index covers a ten-year period, from January 1, 2010, to January 3, 2020, and has significant economic implications.
Design/methodology/approach
In order to address the nonlinear patterns present in the price time series, we investigate the nonlinear auto-regressive neural network as the forecast model. This modeling technique is able to combine a variety of basic nonlinear functions to approximate more complex nonlinear characteristics. Specifically, we examine prediction performance that corresponds to several configurations across data splitting ratios, hidden neuron and delay counts, and model estimation approaches.
Findings
Our model turns out to be rather simple and yields forecasts with good stability and accuracy. Relative root mean square errors throughout training, validation and testing are specifically 4.34, 4.71 and 3.98%, respectively. The results of benchmark research show that the neural network produces statistically considerably better performance when compared to other machine learning models and classic time-series econometric methods.
Originality/value
Utilizing our findings as independent technical price forecasts would be one use. Alternatively, policy research and fresh insights into price patterns might be achieved by combining them with other (basic) prediction outputs.
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Sabrina Silva Valadares, Antonio Moreira De Carvalho Neto, Carolina Mota Mota-Santos and Daniela Martins Diniz
The core of this study is women in mining. The aim of this study was to analyze the perception of women, about their work environment, their career, the human resources policies…
Abstract
Purpose
The core of this study is women in mining. The aim of this study was to analyze the perception of women, about their work environment, their career, the human resources policies and practices and the work–family balance in the context of a multinational organization in the sector.
Design/methodology/approach
The case study was carried through semi-structured interviews with 27 women who work in this organization.
Findings
Although women report that they are capable of exercising any position/function in the company, they perceive wage gap in the investigated organization; that maternity leave and the fact of having children impact their career and their rise to higher positions in the organizational hierarchy negatively; situations of prejudice and discrimination experienced at work. Sometimes subtly, sometimes not so subtly, but they still constitute barriers faced by women in mining.
Originality/value
Although the debate around the issue of gender inequality in organizations is not recent, little has been produced about the working condition of women in occupational fields where male domination is strong, such as mining.
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Barbara de Lima Voss, David Bernard Carter and Bruno Meirelles Salotti
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in…
Abstract
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.
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Akiko Kamimura, Jeanie Ashby, Maziar Nourian, Nushean Assasnik, Jason Chen, Jennifer Tabler, Guadalupe Aguilera, Natalie Blanton, Allison Jess and Justine Reel
Little is known about low-income immigrant parents’ health-related quality of life (HRQoL) associated with their parenting. The purpose of this paper is to examine low-income…
Abstract
Purpose
Little is known about low-income immigrant parents’ health-related quality of life (HRQoL) associated with their parenting. The purpose of this paper is to examine low-income immigrant parents’ HRQoL, depression and stress.
Design/methodology/approach
In the spring of 2015, English speaking and Spanish speaking low-income uninsured immigrant parents utilizing a free clinic (N=182) completed a self-administered survey using standardized measures of parental HRQoL, stress and depression.
Findings
Immigrant parents’ HRQoL related to parenting was lower than general primary care patients. Higher levels of depression and stress were associated with lower levels of parental HRQoL and family functioning. Spanish speakers were significantly more likely to worry about their child’s health or future compared to English speakers.
Originality/value
While both English and Spanish speaking immigrant parents may need assistance addressing the health-related needs of their child, Spanish speakers may be a target audience for outreach programs. It is possible that by improving the health of their child, immigrant parents may see improvement in their own HRQoL and reductions in their levels of stress and depression. Future research should develop parenting classes for low-income immigrant parents targeting the potential health needs of their children, and assess the efficacy of the classes in improving child health and parental HRQoL.
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Bingzi Jin, Xiaojie Xu and Yun Zhang
Predicting commodity futures trading volumes represents an important matter to policymakers and a wide spectrum of market participants. The purpose of this study is to concentrate…
Abstract
Purpose
Predicting commodity futures trading volumes represents an important matter to policymakers and a wide spectrum of market participants. The purpose of this study is to concentrate on the energy sector and explore the trading volume prediction issue for the thermal coal futures traded in Zhengzhou Commodity Exchange in China with daily data spanning January 2016–December 2020.
Design/methodology/approach
The nonlinear autoregressive neural network is adopted for this purpose and prediction performance is examined based upon a variety of settings over algorithms for model estimations, numbers of hidden neurons and delays and ratios for splitting the trading volume series into training, validation and testing phases.
Findings
A relatively simple model setting is arrived at that leads to predictions of good accuracy and stabilities and maintains small prediction errors up to the 99.273th quantile of the observed trading volume.
Originality/value
The results could, on one hand, serve as standalone technical trading volume predictions. They could, on the other hand, be combined with different (fundamental) prediction results for forming perspectives of trading trends and carrying out policy analysis.
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Vincent J. Roscigno, William F. Danaher and Erika Summers‐Effler
Highlights the importance of music in ritual and culture generally, extending the focus to collective action. Argues that music and its emotional and cognitive impacts can be…
Abstract
Highlights the importance of music in ritual and culture generally, extending the focus to collective action. Argues that music and its emotional and cognitive impacts can be fundamental to the construction of social movement culture. Analyses song lyrics from the southern textile strikes of 1929‐1934 in an attempt to show how music and song helped construct a collective identity across relatively dispersed mill villages, shifted accountability for mill workers problems towards the labour process and its beneficiaries and suggested to the listener a collective solution. Discusses the implications of the findings for understanding music, culture and their relation to subordinate group challenge.
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This work presents a review of the state of the art of the present century on academic and scientific production in Latin America related to the concept of Social Innovation. The…
Abstract
This work presents a review of the state of the art of the present century on academic and scientific production in Latin America related to the concept of Social Innovation. The analysis is based on articles published in indexed journals, which makes it possible to understand the existing asymmetry between the conceptual and theoretical veins, of the case studies, as well as of good social innovation practices that have been published in recent years. These debates have in some cases transcended public policies, as well as business and social realities where social innovation is a mechanism and strategy for personal, social, and territorial development. Finally, a Latin American community of researchers and academics around social innovation must be consolidated, who choose to continue building theoretical-empirical bodies following the Latin American reality.