bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recovery of forest structure dynamics following selective logging in lowland dipterocarp Peninsular Malaysia
Authors: Ghazali N M , Said M N M , Kamarulzaman A M M , Saad S N M 
Published: May 2023

Abstract
The selective management system (SMS) practised in Malaysia has emerged to optimise the sustainability of permanently reserved forest management. SMS requires a management regime (felling) to ensure economical harvesting and appropriate residual stands for the logging cycle, including ecological balance and environmental quality. SMS includes a Post-Felling Forest Inventory (Post-F) sequence. Post-F is used to obtain information on the remaining stands and other plants to determine the silvicultural treatment of a logged area. However, data gathered from Post-F are insufficient to track and collect information on forest structure dynamics recovery after logging. Thus, this study is to further understand the applicability of remote sensing technologies for forest recovery structure assessment after selective logging in the lowland dipterocarp forest of Peninsular Malaysia. Understanding the structural and composition changes occurring in lowland dipterocarp forests is vital for forecasting these ecosystems in the future. This study uses temporal dynamics (5, 9, 16, 26 and 32 months) of canopy cover images obtained from Landsat 8 after selective logging. Using the Carnegie Landsat Analysis System (CLASlite), this study applies Automated Monte Carlo Unmixing Analysis (AutoMCU) algorithm to derive per-pixel fractional cover estimates of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil. The relationship between these three indicators has shown the dynamic growth pattern of the forest area after logging. Differences can be seen via changes in the PV, NPV and bare soil image over various time periods. The information derived from this study is vital for forest conservation strategies after logging, thus enhancing Sustainable Forest Management in Peninsular Malaysia.
Spatio-temporal analysis of land use and land cover changes in Nguru Wetland, Yobe State, Nigeria
Authors: Hassan G , Syakir M I 
Published: May 2023

Abstract
Rapid urbanization in Nguru has recently contributed to significant land use/land cover (LULC) changes, the purpose of this research is to study the spatio-temporal trends of LULC changes in Nguru LGA, Yobe State, Nigeria. The factors that contributed to LULC changes are: bio-physical impacts, desertification, sand-dunes encroachment, loss of vegetal cover, a decrease in bird population, climate change, the conversion of farmlands to built-up areas, accumulation of pollutants in flood risk disaster and decrease in annual rainfall. We used Multi-temporal Landsat data to analyze the LULC pattern in the study area based on 20 years data. Results showed a significant urban expansion, with built-up area increased from 446 hectares in 2001 to 768 hectares in 2011 and 2,483 hectares in 2021. The green area’s land area decreased from 7932 hectares in 2001 to 6,404 hectares in 2011 and 365 hectares in 2021. These findings may provide a snapshot of the LULC trends from spatial-temporal perspective of which useful to the conservationists, urban planners, environmental managers and decision makers in implementing sustainable land-use management and strategies for the study area. The Nigerian government’s environmental regulations for wetlands and lakeshore aimed to protect wetlands as habitats for various animal and plant species, ensure the conservation and responsible use of wetlands and their resources in Nigeria, and ensure water catchments are protected and floods are monitored.
Conversion of Imperata cylindrica, plastic face mask and mango peels to solid fuel briquette
Authors: Jalil N A A , Mokhtaruddin N A , Chia C H , Ahmad I K , Saad M J , Sarif M 
Published: May 2023

Abstract
The demand for briquette is rising with the increasing of urbanization. Briquettes is mainly used as fuel and heating component. In addition, briquette is used in various industries for over the years. In this study, Imperata cylindrica and mango peels along with face mask were anticipated to boost the properties of the solid fuel briquette. Proximate analysis (moisture content, ash content, volatile matter and fixed carbon) and ultimate analysis (CHNS and calorific value) conducted for the briquette samples before and after the carbonisation process. The characteristics and properties of face mask, mango peels, and Imperata cylindrica are significant for the contribution of the optimal ratio of solid fuel briquettes made from these combination materials. Based on the findings, it can be concluded that briquettes made from Imperata cylindrica: mango peel produce the best results. The findings indicate that the briquette has low moisture content, 3.0%, high volatile matter, 37%, low ash content, 5.7%, and high fixed carbon, 54.8%. The analysis of carbon, hydrogen, nitrogen, and sulphur (CHNS) found that carbon content is 68.8%. The contents of hydrogen, sulphur, and nitrogen were 4.5%, 0.3%, and 0.96%, respectively. The calorific value obtained was 24.2 MJ kg-1.
An overview of economic valuation of ecosystem services in protected areas and its roles in achieving Sustainable Development Goals (SDGs)
Authors: Al-Saedi T K , Syakir M I 
Published: May 2023

Abstract
Protected areas (PAs) provide a variety of benefits and services related to human welfare, poverty alleviation, and sustainable development. However, economic valuations of PAs are poorly measured to date. The majority of PAs management policy frameworks are based on biodiversity conservation. The purpose of this overview is to highlight the importance of PAs in achieving Sustainable Development Goals (SDGs) by reviewing current and past studies related to the economic value of ecosystem services and the valuation methodologies of PAs at local, regional, and national levels. In addition, the role of PAs in enhancing the sustainability of ecosystem services has been discussed. Furthermore, two case studies related to the ecosystem-economic perspective of PAs; Australia’s Great Barrier Reef and India’s Nagarhole Park, were highlighted. In general, the economic value of PAs is based on the components of ecosystem services, such as provisioning, regulating, supporting, and culture. The management of PAs is critical for valuation of species conservation as one of the standards derived from the ecosystem services. Additionally, it improved the level of financial income of the communities, their educational and health levels, revitalizing local businesses and providing job opportunities through the success of PA’s management strategies as local, national, and international tourist destinations. This review provides a snapshot of the roles of PAs in achieving Sustainable Development Goals (SDGs), useful for future researchers, planners, park managers, and policymakers to develop policies for sustainable investment and improvement of PAs.
The effect of physical properties of sandstone on the compression strength of rock
Authors: Shulhin K , Aprillah B , Alpiana  , Rahmawati D , Salsabila A A , Iqbal M 
Published: May 2023

Abstract
Sandstone are commonly found on Lombok Island. The research aims to determine the sandstone’s physical and mechanical properties against the uniaxial compressive strength test. Analysis of physical properties for this research was carried out to determine the dimensions of size, moisture content, specific gravity, and bulk density, while the analysis of mechanical properties was to obtain compressive strength values. The original dry and wet bulk weights were obtained by testing the physical properties and compressive strength of sand and trass. The results from the samples in the Gunung Jae show that the average water content was 8.275%, the specific gravity was 2.37 grams, the bulk density was 0.485 gr/cc, and the compressive strength test was the highest value of 14 mm with the stress of 0.18 MPa.
Research on The Impact of Ciliwung River Water on The Surrounding Environment in The DKI Jakarta Area
Authors: Rajagukguk J R , Pranoto D A 
Published: May 2023

Abstract
Ciliwung River flows through central Jakarta, passing through many residential and densely populated areas that cause heavy pollution in the Ciliwung River resulting from wastewater and solid waste. This research aims to know the water quality and pollution level in the Ciliwung river and determine the locations to install water quality online monitoring stations. The research method used in this study is to analyze the quality of water samples taken from several points of the Ciliwung River. The analysis results show that the Ciliwung river is highly polluted, especially in the areas going downstream of the river. In addition, the analysis results have determined 8 (eight) points/locations where the online water quality monitoring devices will be installed. Due to limited funds, however, only 3 (three) online monitoring devices are currently installed on site, representing upstream, middle, and downstream areas of the Ciliwung river.
The inherent strain method for additive manufacturing: critical analysis and new inherent strain rate method
Authors: Bellet M , Keumo Tematio J , Zhang Y 
Published: May 2023

Abstract
To reduce computation time, the inherent strain (IS) method is popular. It consists in adding layers, at room temperature, with an “inherent strain” representing the plastic deformation undergone during deposition. An IS method is developed, including a direct determination of the IS tensor based on the transient thermo-elastic-viscoplastic (TEVP) simulation. Validation is achieved: taking full-field inherent strains, the IS method allows retrieving TEVP predictions. However, application to a full part, for which a set of inherent strains must be conserved all along the construction, leads to poor results, far from TEVP. As an alternative, a new “inherent strain rate” (ISR) method is proposed, consisting in linearizing TEVP resolutions. Combined with an on-line learning technique, this strategy leads to results identical to TEVP reference, with still a significant speed-up. This makes the proposed ISR method very promising.
A 3D Multiscale Model for Prediction of the Microstructure Evolution in Ti6Al4V Components Produced by Laser Powder Bed Fusion
Authors: Nastac Laurentiu 
Published: May 2023

Abstract
A transient 3D multiscale model has been created to simulate the evolution of solidification microstructures rapidly and effectively in Ti6Al4V parts produced through Laser Powder Bed Fusion (LPBF). The microstructure simulation tool has been enhanced to account for rapid solidification conditions in Ti6Al4V alloys during processing of multi-layer multi-track LPBF parts. The simulation tool can evaluate the impact of part geometry, lase power input, laser speed, and laser beam shape on the formation of the microstructure in LPBF-processed Ti6Al4V alloy. The multiscale model considers several factors, including preferential crystallographic growth direction, isomorphism, epitaxy, melt pool motion, and temperature gradients to generate the observed texture and morphology of the microstructure in Ti6Al4V components. The model can evaluate various microstructure characteristics, such as grain size and texture. Consequently, it could aid in controlling the formation of solidification microstructures in Additive Manufacturing (AM) processed parts. The simulation tool has been previously validated by using IN625 laser remelting experiments made by National Institute of Standards and Technology. The 3D simulation tool can also be utilized to predict the microstructure formation in Ti6Al4V components produced by the Electron Beam AM processes.
Simulation of the solute transport and microstructure evolution during the selective laser melting process
Authors: Ren Neng , Li Jun , Panwisawas Chinnapat , Xia Mingxu , Dong Hongbiao , Li Jianguo 
Published: May 2023

Abstract
Selective laser melting is of great expectation to be used in additive manufacturing of aerospace components with complex geometry. However, there are still defects in the built parts, such as solutal segregation and unexpected microstructure, which contribute to cracks and lead to failure. At present, most of the simulations focus on the macroscopic grain structure, and the solute transport process has not been well demonstrated yet. In the present work, we develop a two-way fully coupled model based on cellular automaton and finite volume method to simulate the solute transport and dendritic structure evolution during the melting and solidification of the SLM process. The results reveal the microstructural evolution and solute transport during the melting, spreading, and smearing of the powder. The proposed model framework shows good potential to be applied to further numerical investigation on the solidification behaviours of the SLM process.
Thermo-mechanical modelling of additive manufacturing: activation of non-constructed domain and effect of kinematic hardening
Authors: Keumo Tematio J , Ravix L , Zhang Y , Bellet M 
Published: May 2023

Abstract
A thermo-mechanical finite element model is developed for additive manufacturing by directed energy deposition (DED). The simulation is conducted at the part scale by modelling the progressive deposition in the way of the fraction of the layer. To incrementally resolve the displacement, strain, and stress fields, a theoretical formulation for the kinematic positioning is proposed to minimize the distortion of the non-constructed fraction by considering current displacement and strain in the constructed part, which can resolve the discontinuous problem at the interface for a patch of material depositions. Moreover, it is found that the kinematic hardening couldn’t be ignored for the back-and-forth deposition mode of the DED process. The application for a turbine blade with a strong curvature is adopted, and the distributions of distortion and stress during mid-construction and final construction are studied.
A 3D simulation of grain structure evolution during laser rescanning process of powder bed fusion additive manufacturing
Authors: Kang K , Yuan L , Phillion A B 
Published: May 2023

Abstract
Laser powder bed fusion (LPBF) is an extensively used additive manufacturing process that can build metal parts with complicated geometric designs. However, because of the rapid solidification conditions and the layer-by-layer building, its application is challenged by products having poor surface quality and reduced mechanical properties. The laser rescanning process is often used as a refinement method during LPBF to improve the quality of products. In this study, grain structure formation during the LPBF laser rescanning process is modelled by a 3D cellular automaton based microstructure model coupled with finite element analysis. The coupled model considers different nucleation mechanisms, including epitaxial growth, which are applicable to rapid solidification in melt pool. The model is adapted to reproduce the grain structure and evolution of an Al-Si alloy manufactured by LPBF utilizing a laser rescanning strategy. The effects of laser remelting on the characteristics of the grain structure (i.e., the grain size, aspect ratio and orientation) are evaluated. The mechanisms that enable unique grain structure (i.e., grain refinement) are discussed.
Phase-field study of polycrystalline growth and texture selection during melt pool solidification
Authors: Tavakoli Rouhollah , Tourret Damien 
Published: May 2023

Abstract
Grain growth competition during solidification determines microstructural features, such as dendritic arm spacings, segregation pattern, and grain texture, which have a key impact on the final mechanical properties. During metal additive manufacturing (AM), these features are highly sensitive to manufacturing conditions, such as laser power and scanning speed. The melt pool (MP) geometry is also expected to have a strong influence on microstructure selection. Here, taking advantage of a computationally efficient multi-GPU implementation of a quantitative phase-field model, we use two-dimensional cross-section simulations of a shrinking MP during metal AM, at the scale of the full MP, in order to explore the resulting mechanisms of grain growth competition and texture selection. We explore MPs of different aspect ratios, different initial (substrate) grain densities, and repeat each simulation several times with different random grain distributions and orientations along the fusion line in order to obtain a statistically relevant picture of grain texture selection mechanisms. Our results show a transition from a weak to a strong ⟨10⟩ texture when the aspect ratio of the melt pool deviates from unity. This is attributed to the shape and directions of thermal gradients during solidification, and seems more pronounced in the case of wide melt pools than in the case of a deeper one. The texture transition was not found to notably depend upon the initial grain density along the fusion line from which the melt pool solidifies epitaxially.
Modeling residual stresses of functionally graded deposits using the PTAAM
Authors: Bonias Geoffrey , Henein Hani , Wolfe Tonya B. 
Published: May 2023

Abstract
High maintenance costs due to significant abrasive wear of components is experienced in the energy and mining sectors despite the current use of tough and hard coatings. During the coating process significant tensile residual stresses may build up and result in premature failure of a component. These tensile stresses can be reduced by adopting functionally graded structures of the composite. The main goal of the present study is to design an ideal material gradient in the additively manufactured composite using the plasma transferred arc (PTA) with a WC-Ni alloy graded in WC. To develop a comprehensive analysis of the functionally graded deposit, the thermal history of the WC and Ni alloy powders are first simulated as they travel through the plasma and deposit on the substrate. The initial temperature of each deposited bead depending on the WC content is deduced. These results are used as an input to predict the temperature and stress history of the solidifying deposit. Thermal stresses are computed and trends of residual stresses are obtained as a function of the WC gradient selected. The trends obtained are compared quantitatively before concluding on the most favorable gradient for this wear resistance application.
Effect of powder properties on mesoscale thermal FEM simulations of powder bed additive manufacturing
Authors: Upadhyay Meet , Sinclair Chad , Maijer Daan 
Published: May 2023

Abstract
Numerous studies have used FEM simulations to assess the effects of the heat source parameters on the melt pool volume during metal powder bed additive manufacturing. However, considerable debate still exists on how to incorporate the evolution of the thermophysical properties used to describe the powder as it undergoes heating, melting, consolidation and finally solidification. For single layer studies, since powder volume is much smaller compared to the substrate volume, highly detailed, computationally expensive powder property descriptions may not provide a commensurate increase in accuracy of simulation results. This study aims to quantify the effect of powder properties on the melt pool volume created during electron beam melting of Ti6Al4V powder using predictions from a FEM-based heat conduction model. The dependence of thermal conductivity, specific heat, and density of the powder on temperature and beam power density will be studied. Additionally, the relevance of the powder properties with changing layer height and beam power and speed will also be quantified.
Toward semantic standard and process ontology for Additive manufacturing
Authors: Gouttebroze S , Friis J , Hovig E W , Boivie K 
Published: May 2023

Abstract
Advanced modelling of additive manufacturing often requires the combination of models at multiple scales and multi-physics. Therefore, building the modelling workflow describing the process is complicated. The modelling is also only a part of the innovation process and must be connected to practices, experimental work, and characterisation. Efficient communication and data exchange between the different actors could quickly become a challenge. Recent developments in the frame of the EMMC (European Material Modelling Council) and in the EU project OntoTrans points toward the early integration of semantic description and the creation of dedicated domain ontologies. This require an unambiguous and consistent use of terms and definitions for various concepts within each field of technology, and international standards is an available source for structured technical terms and definitions. For additive manufacturing (AM) the international standard ISO/ASTM 52900 “Additive manufacturing - General principles - Fundamentals and vocabulary” is the internationally recognised source for terms and definitions. Basing the ontology on the AM terminology standard will greatly facilitate integration of AM processes as a part of an industrial manufacturing system. Therefore, the present work attempts to harmonise the standard terminology and the ontology concepts. Then, to improve the impact and connection to material science, the concepts will be connected to a microstructure domain ontology and to the top- and middle-level ontology EMMO. The conceptualisation and application of the ontologies will be illustrated through simple examples of process and material modelling.
Calculation of thermal features in welding and additive manufacturing
Authors: Mendez Patricio F. 
Published: May 2023

Abstract
This paper summarizes multiple engineering expressions that enable the prediction of thermal magnitudes of interest associated with moving heat sources. The expressions use only fundamental parameters available before performing any experiments, and their calculation is algebraic, without the need for numerical methods. All expressions are based on the fundamental governing equations of heat transfer in the solid. The magnitudes predicted include maximum width and its location, maximum penetration, thickness of HAZ, maximum temperature and its location, leading and trailing edge of an isotherm, heating and cooling rate, aspect ratio of an isotherm, melting efficiency, cooling time from 800°C to 500°C, solidification time, and maximum distribution of a heat source to reach a target temperature. Parameters involved include heat source power and speed, thermal conductivity and diffusivity of the substrate material, temperature of interest and preheat or interpass temperature. Temperature-dependent properties are accounted for by the use of effective properties. The expressions proposed can be extended into sophisticated geometries for welding and specific additive manufacturing cases.
Transient simulation of melt flow, clogging, and clog fragmentation inside SEN during steel continuous casting
Authors: Barati H , Wu M , Kharicha A , Ludiwg A 
Published: May 2023

Abstract
Clogging of submerged entry nozzle (SEN) during continuous casting of steel is an undesirable phenomenon leading to different problems like flow blockage, slag entrainment, nonuniform solidification, etc. A transient numerical model for nozzle clogging based on an Eulerian-Lagrangian approach was developed and it covers the main steps of clogging: (a) formation of the first oxide layer by chemical reactions on the steel-refractory interface; (b) motion of non-metallic inclusions (NMIs) due to the turbulent melt flow towards the SEN wall; (c) interactions between the melt, the NMI, and the wall; (d) formation and growth of the clog by the deposition of NMIs on the clog front and the flow-clog interactions; and (e) detachment/fragmentation of a part of clog due to the flow drag force. Clogging in an industrial scale SEN was simulated. The simulated clog front was compared with real as-clogged SENs. The modeling results have successfully explained the SEN clogging induced transient flow phenomenon in the mold region, i.e. the transition from the stable to an unstable and non-symmetrical flow.