bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal dynamics in relation to groundwater quality in Sharada industrial area of Kano Metropolis, Nigeria
Authors: Suleiman H A , Hanafiah M M
Published: May 2023

This study examined the seasonal dynamics in relation to groundwater quality in the Sharada industrial area of the Kano Metropolis, Nigeria. The study samples were collected from groundwater within 500 m distance from industries and residences within the study area. The study samples for the dry season were collected in January, February and March of 2021 while the wet season samples were collected in July, August and September of the same year (2021). At each sampling point, samples were taken in triplicate (n=3) to ensure that the results obtained were free from bias. The physical, chemical, biological, and heavy metal characteristics of the samples collected were analysed at the laboratory of the Centre for Dryland Agriculture Bayero University with the use of standard APHA procedures. The results of the water samples were further analysed with mean, standard deviation, and correlation. The results of the analysis revealed that the concentration of copper (Cu), chromium (Cr), Manganese (Mn), total dissolvable solid (TDS), chlorine (Cl), and sodium (Na) in groundwater of Sharada Industrial area are high during the wet season while the concentrations level of total suspended solid (TSS), calcium (Ca), Escherichia coli (E. coli) and Fecal coliform (F.coli) are high during the dry season. Despite the fact that there are more parameters that have higher concentration than permissible limits during the wet season, the dry season was characterised by a higher relationship among water parameters than during the wet season. This led to the conclusion that seasonal differences in groundwater level influence the concentration level and relationship among water parameters in Sharada industrial area. Hence, the water in the Sharada industrial area needs to be treated differently during the wet and dry seasons before consumption.
Dam Break Flood Mapping and Analysis Using Open Source GIS Tool and Data
Authors: Samsudin S H , Zuhaily N A , Setu A , Muda R S , Amin M F M
Published: May 2023

The impact of climate change may influence on extreme weather conditions and may lead to high intensity precipitation, which will impact on huge structures such as dam. Although risk mitigation and protection of dams from advanced technical expertise have been reviewed regularly, a maximum non-risk guarantee is not achievable, and incidents may occur due to water that usually flows over a spillway and high-speed discharge or unexpected peak discharge. Hence, the immediate impact of dam failure is on the population at risk near the downstream area. This study evaluates the impact of dam break scenario under probable maximum precipitation (PMF) condition at Puah hydropower dam. The aims of this study are to determine the potential risk area at downstream and to assess the flooding impact on population and public facilities due to dam break event. Integration of an open source GIS tool, Google Satellite Image, Open Street Map, and flood hazard map derived from hydrodynamic model has been used to efficiently analyse the impact of dam break flood by using spatial analysis method, and to generate possible evacuation route network. Analysis has estimated that 187,796 people at risk, 3,177 km of road, 2-unit hospital and 76 amenities (mosque and school) will be impacted. This study portrays the possibility of using open source data and tool as an alternative for emergency preparedness application. The method used in this study could be adopted to other area of interest and disaster event, helping the local authorities for disaster emergency preparedness and early warning systems focusing on rescue work if disaster occurs.
Local variations of landslide factors in Pulau Pinang, Malaysia
Authors: Zulkafli S A , Abd Majid N , Rainis R
Published: May 2023

A landslide is one of the most notorious natural disasters, resulting in massive losses and significant damages. Thus, this paper aims to analyze the spatial heterogeneity of the influencing factors which later inspect the relationship between the factors and landslide occurrences. A total of 988 landslides historical data and eight landslide factors were obtained from proper field validation and maps provided by those concerned in the government, including distance to roads, distance to rivers, distance to faults, slope angle, curvature, slope aspect, land use, and lithology. Geographically Weighted Logistic Regression (GWLR) is introduced in this paper to carry out the local analysis, resulting in the slope angle and the slope aspect playing the most significant role in influencing landslides. The Akaike’s information criterion (AICc) of GWLR is 824.51 which has a lower value than the global regression represented as 906.09 revealing that GWLR is the best model. Other evaluation criteria such as deviance, local percent deviance explained (pdev), and Bayesian information criterion (BIC) also validate the significance of the GWLR model. The GWLR results show the degree of spatial variation in the relationship between landslides and the influencing factors in the study area as the coefficient values of every factor are inconsistent, providing a reference for managers to formulate targeted decision-making measures. In the meantime, urgent action to sustain this natural disaster as suggested in the SDG 13 has to be taken earnestly to avoid bigger impacts on both society and the environment.
Erosion-deposition Prone Assessment Along the Kelantan and Terengganu Coasts Due to Sea Level Rise
Authors: Benson Y A , Hasan M M , Jamal M H , Lee L H , Anthony D , Mohamad K A , Hamzah S B , Othman I K
Published: May 2023

The erosion-prone zone is characterised by nearshore sand formed by the combined action of tides, wind, and recurring waves crashing on the beach. By running perpendicular to the coastline and bathymetry, 51 cross-shore sections were chosen from a total of 54 to study longshore transport along the beaches of Kelantan and Terengganu. The hydrodynamic model was used to determine water level, current speed, and spectral density, while the Spectral Wave Model and LitDrift were used to construct boundary wave variables and Net Transport across each sector. The model output was compared to previously published erosion-prone zones in the NCES Report (2015), and the results were agreed. The net transfer varies based on the angle of the coastline, the direction of the waves, and the beach profile. The net transport ranges from -693,000 m3/year to 444,000 m3/year depending on the beach profile, wave direction, and angle of the coastline. Net transit for each section was also calculated for 2030, 2050, and 2100, taking into consideration sea level rise. The most recent IPCC assessment (AR6) was applied to generate SLR forecasts for year 2030, 2050, and 2100. According to the statistics, all sections are expected to increase in year 2030, whereas only 53% and 67% are expected to develop in year 2050 and 2100, respectively. From 2030 to 2050 and 2100 to 2020, total net transport along the Kelantan and Terengganu beaches grows by 9.5%, 10%, and 4.5%, respectively.Net transportation is expected to grow until 2050, then steadily decline until 2100. However, by using a better anticipated wave model, the results of this inquiry can be improved.
Reduction effect on the catalytic performances of NiAl-SPC takovite catalysts in syngas synthesis process
Authors: Abdelsadek Z , Gonzalez-Cortes S , Cherifi O , Halliche D , Masset PJ
Published: May 2023

In the downstream of the Oil & Gas industry and decline in oil production, the NiAl-HT derived hydrotalciteis a candidate as catalyst to produce syngas in the methane dry reforming process. Hydrotalcite are lamellar compounds of general formulation[M1-x
2+ Mx
3+ (OH) 2]x+[An-] x/n .m H2Owhere the ionic or cationic character can be tuned by the choice of the metal nature and oxidation degree. NiAl-SPC samples were obtained by coprecipitation at constant alkaline pH, then the product was thermal treated at 450°C for 6h to obtain mixed oxides phases. Samples prior and after calcination were characterized by XRD, ICP, BET, FTIR, SEM, TEM, TPR, TGA/DTA and Raman. Catalysts were examined in CO2 dry reforming of methane to examine the influence and the role of the reducibility ability on the catalytic reactivity and stability of NiAl-SPC hydrotalcite generics. They were reduced at 500°C, 600°C, and 700°Cfor 1h to evaluate the effect of its morphology changes on the carbon dioxide reforming of methane carried out at 700°C versus time on stream. It was shown that the reduction conditions strongly influence the reactivity of Ni metallic active phase catalyst, catalytic selectivity and its resistance to carbone deposit for methane reforming by carbon dioxide.This study proposes a further understanding of the synthesis, effects of additives and treatment of hydrotalcite as a catalyst for the DRM reaction. This knowledge will also be beneficial for the development of catalysts for other high temperature industrial applications (ammonia cracking, alcohol to hydrogen conversion...) and for longer term applications such as drug delivery or energy storage materials.
Analysis of Navigation Satellite System based on the Ground Control Points (GCP) at Universiti Kebangsaan Malaysia
Authors: Suhaimi K , Sahar N M , Badron K
Published: May 2023

This study presents data measurements to identify the best navigation system in terms of its positioning accuracy. The data global positioning system measurements is done using a GPS South device measured in four locations which are one random point and three different places based on the Ground Control Points (GCP) in Universiti Kebangsaan Malaysia (UKM). The coordinates of these locations are already in the Cassini Soldner Selangor Coordinate system. The results and analysis of signal noise to ratio (SNR) and path loss is discussed to indicate the performance of positioning accuracy among the four existing Global Navigation Satellite System (GNSS). The Global Positioning System (GPS) signal is dominant in location A and China’s BeiDou Navigation Satellite System (BDS) signal is also dominant for other three locations. In general, the BDS signal had the highest number of signals detected in this experiment which is total of 57 signals in four locations. By evaluating the positioning accuracy can improve the environmental studies such as tracking, monitoring, surveying, and mapping of climate change.
Life cycle assessment of carbon capture, utilisation and storage technologies: An analytical review
Authors: Chelvam K , Hanafiah M M
Published: May 2023

The impact of climate change is more evident now than ever due to the environmental burden accumulated over the past two decades. Decarbonising methods such as carbon capture, utilisation and storage (CCUS) technologies are the future of the green economy and are considered one of the most significant alternatives for mitigating carbon emissions. Therefore, this review mainly focuses on life cycle assessment (LCA), the current state-of-the-art tool to determine the environmental performance of the technologies. This paper aims to assess papers published from the year 2019 to 2022 from all around the world to understand the trend, challenges, and prospects of CCUS technologies in reducing carbon and environmental impacts. This review concludes that the employment of carbon capture technologies can significantly reduce greenhouse gas (GHG) emissions but also increase other environmental burdens such as acidification, eutrophication and ecotoxicity depending on the type of carbon capture method used, energy penalty and the rate of oxides of nitrogen (NOx) emitted from the carbon capture infrastructure. Furthermore, Carbon Capture Utilisation (CCU) is a viable option to be employed in industries mainly to produce chemicals and use the captured carbon directly to combat GHG emissions with the proper modification of the carbon conversion method of the plant and the application of renewable energy. Although the Carbon Capture Storage (CCS) technology has an overall great impact on reducing Global Warming Potential (GWP), the increasing demand for fuel for the infrastructure causes environmental trade-offs with an increase in GHG emissions and other impact categories. The findings of this research would help in developing and implementing improvised methods and will provide a clear view of the prospects of CCUS technologies which will assist in decision-making.
Simplification techniques of CFD simulations and experimental validation for fluid flow analysis in PEM fuel cells: A review
Authors: Sarjuni C T A , Lim B H , Majlan E H , Rosli M I
Published: May 2023

Studies on proton exchange membrane fuel cells [PEMFCs] have shown that poor fluid distribution can lead to a higher probability of concentration, ohmic, and activation losses which affects the overall electrochemical and power output performance as well as reduced cell durability. Hence, understanding fluid dynamics are imperative to identify strategies that will improve the fluid distribution uniformity and optimise reactant transport. Most fluid flow studies for PEMFCs are done through computational fluid dynamic [CFD] simulations as it is a cost-saving research method with dependable accuracy levels. In some cases, real-life experiments are executed concurrently to justify the simulation results and theories made. However, there are instances where simplifications are needed for both CFD simulations and experiments for easier and clearer fluid analysis. This short review will first discuss the simplification strategies used to simulate PEMFC models in both 2-dimensional [2D] and 3-dimensional [3D] dimensions, covering theories or concepts that can prove the dependability of the methods employed. Then, the next part will explain the validation techniques applied to justify simulation results, including the types of measuring methods employed to generate the clearest capture of fluid flow and behaviour in the PEMFC models. The overall discussion will provide a better insight into choosing a suitable combination of simplification, validation, and measuring methods for increased quality and accuracy of future studies on fluid flow analysis.
Modified combination of triple split ring resonator based triple band single negative metamaterial for satellite applications
Authors: Hossain M B , Faruque M R I , Abdullah S
Published: May 2023

This paper investigates a modified combination of triple split ring resonator (SRR) based triple band single negative metamaterial for satellite applications. The proposed unit cell structure has a triple split ring resonator i.e. square, circular and rhombus shape. The lower plane completely encloses the FR-4 substrate with a thickness of 1.6 mm, on top of which the metallic resonating structure with thickness of 0.035 mm is attached. The structure provides quad band resonances of transmission coefficient (S21) at 2.02 (S-band), 6.77 (C-band), and 13.22 (Ku-band) GHz with magnitude of -27.8, -23.2, and -27.2 dB, respectively and also offers the wider bandwidth. The plot of relative permittivity, permeability, refractive index and impedance is used to explain the metamaterial behavior. Additionally, a plot of the electromagnetic field and surface current analysis for a separate frequency that belongs to the S, C, and Ku band makes the unit cell structure to help illustrate the metamaterial behavior. The effective medium ratio (EMR) of the structure is 14.85, demonstrating its compactness. The performance of the structure is validated through the simulation result using CST Microwave Studio and HFSS simulator. The suggested structure will be a possible option for satellite communication (S, C and Ku-band) because of wider bandwidth and excellent EMR.
Characteristics of consumer towards development of sustainable e-waste management in Malaysia
Authors: Sofian D D , Hanafiah M M , Woon K S , Hassan F M
Published: May 2023

The problem of rising electronic waste or known as e-waste generation has not only been faced worldwide, but has also had a significant impact on Malaysia, since it has become a serious environmental concern and contribute to the effect on human health, especially in major urban area. Many initiatives have been done to address the concern of improper e-waste management. Thus, this study intends to determine household characteristics of consumer behaviour toward managing e-waste in an environmentally sound manner as a first step in alleviating the problem. Putrajaya a government administrative centre, was chosen as the case study to represent Malaysia’s paradigm of sustainable urban cities. A constructive questionnaire was distributed to 50 Putrajaya households using random sampling, and the data was analysed using IBM SPSS Statistics version 28 and Microsoft Excel. It was discovered that >40% of respondents have good understanding about e-waste management based on their levels of awareness, knowledge, and perception that have significant influence on attitudes toward e-waste management. Furthermore, views regarding e-waste management on impact of recycling behaviour were also determined. On the other hand, the consumers demonstrate a good attribute (80%) in terms of their willingness to make changes toward a sustainable e-waste management. This study provides important information to policymakers, allowing them to take the required steps to increase recycling among Putrajaya homes while also considerably improving e-waste management.
Assessment of household-level adaptation strategy to flood in East Coast Malaysia
Authors: Nor Diana M I , Nurul Atikah Z
Published: May 2023

The increase of flood-related event has affected not only property damage but also casualties among the community that lives in a flood-prone area. Increasing risk of exposure to the flood-related event will consequently affect the livelihoods of a community. Therefore, the adaptive capacity of a community is vital for farmers to be resilient in any disaster or risk-related situation. Thus, this study will determine a household-level adaptation strategy to flood on the east coast of Malaysia by using the assessment of the Livelihood Vulnerability Index (LVI). 100 paddy farmers living in Kota Bharu Kelantan were chosen as the respondents and the analysis of this study focuses on the adaptive capacity of the respondents. Indicators such as sociodemographic profile, livelihood strategies, and social network is used to assess farmers’ vulnerability and their adaptation capacity. Overall finding of the study shows that the paddy farmers’ household is in less vulnerable to flood events (0.36813). The result shows that social network (0.5275) is the least indicator to have higher adaptive capacity compared to indicators like livelihood strategies (0.3883) and sociodemographic profile (0.3485). The element of adaptive capacity is crucial to increase household resilience as well as to sustain the need of a household and decrease their vulnerability to a natural disaster such as flood. Therefore, assistance from the government and non-government agencies is needed to assist and support this community to promote well-being and quality of life.
Screening and optimization of a novel gallic acid and tannase production under semi quantitative and quantitative methods
Authors: Abdulshaheed A A , Hanafiah M M , Muslim S N
Published: May 2023

Tannin acyl hydrolase as the common name of tannase is an inducible extracellular enzyme that causes the hydrolysis of galloyl ester and depside bonds in tannins, yielding gallic acid and glucose. The main objective of this study is to find a novel gallic acid and tannase produced by Acinetobacter Baumannii. A number of optimization steps were followed in order to improve the highest production of gallic acid and tannase. In present study, A. baumannii were isolated from ICU burn. A. baumannii was examined by microscopic examination, morphological and biochemical assay including oxidase and catalase. The following parameters were considered and determined the effect of pH, temperature, incubation period and inoculum volume on gallic acid and tannase production. It was observed that A. baumannii gave the highest yields of gallic acid and tannase using semi-quantitative and quantitative methods. A novel A. baumannii stimulated production of gallic acid and tannase using 0.5% tannic acid in agar medium. The maximum production of gallic acid and tannase by A. baumannii was recorded at pH 5.5, temperature at 37°C, 72h of incubation period and 10% of the inoculum volume. The results concluded that the highest yields of gallic acid (47.54 mg/ml) and tannase (50.12U/mg) were obtained under improved conditions.
Greening strategy through implementation of sustainable landscape design towards low carbon school
Authors: Mohamed S A , Ismail W A W , Hamid N H A , Kurzi N S , Hasan R , Othmani N I , Bak Y L , Ramlee N
Published: May 2023

The increased societal attention and urgency towards combating global climate change and transitioning the position towards Low Carbon Cities (LCC) has prompted many green initiatives developed by government agencies including schools to seek solutions through promoting eco-school planning development as part of the Environmental Education (EE) awareness being emphasis in curricula. This research explores the underlying mechanism of the greening elements as one of the planning initiatives which enable the inclusion of how low carbon practice action plans can be conducted in school. The methodology adopted emphasized the ground case study at Sekolah Kebangsaan Tangok, Bachok, Kelantan to testify to the integration of theory and practice of sustainable low carbon in the school community with environmental education. Such integration draws on attention to contextual knowledge of reducing carbon dioxide emissions as one of the most important factors in the implementation and execution of greening components for a sustainable school program. The discussion of findings concentrated on the implementation of greening strategies from sustainable landscape design and framework for carbon measures from three components, which are the trajectory of low carbon target, benefits analysis matrix, and constraint analysis that can be implemented in school to track the level of CO2 emissions and sequestration. This research provides a significant contribution in creating ‘commercialized’ environmental knowledge to the school communities that paved the way towards transition for Low Carbon Society as the social sustainable strategy that inculcates climate change adaptation for the future generation.
Applicability of green building rating tools in minimizing construction waste within the Iraqi building projects
Authors: Abdulaali H S , Usman Ismar M S , Korandeh M E , Alqawzai S , Alkhafaji S
Published: May 2023

Due to the rapid growth of the building sector, a tremendous amount of waste is generated, which has become an alarming issue for every country. Therefore, there is a substantial need to implement a sustainable way to minimize the construction solid waste (CSW), generated through the construction activities. Construction solid waste management (CSWM) is an essential method for fostering sustainability in the construction industry. It is considered as one of the indispensable advantages, which are stipulated in the green building systems (GBRSs). The aim of this study is to explore the potentials of various GBRSs in minimizing the solid waste generated by the construction activities in the Iraqi building sector. Firstly, a description of research methodology is provided based on a systematic review and text mining approach. Then, An extensive review on CSW and GBRSs as well as the recent research trends on the implementation of CSW minimization in Iraq. After that, applications of GBRSs on CSW minimization are addressed. Next, the major challenges and obstacles to the application of GBRSs in minimizing the CSW are addressed. Finally, concluding remarks are withdrawn. Based on the findings, it was found that it can be concluded that reuse, reduce and recycling principles of construction waste management have become a worldwide phenomenon. However, previous research studies have not considered the achievement of CWM along with GBRSs promotion within Iraqi construction industry. The information of this research can be beneficial to both Iraqi researchers and practitioners.
An Analysis of Blasthole Condition towards Toxic Fumes Generation from Blasting Activities in Surface Mine
Authors: Hartami P N , Maulana Y , Purwiyono T T , Tuheteru E J , Kusumo D H , Putra D , Burhannudinnur M
Published: May 2023

One impact of blasting activities is the release of toxic fumes capable of disturbing living creatures around the blasting zone. Fumes are affected by several factors, including blasthole conditions. Measurement for this research was performed in a coal mine called PT. Kaltim Prima Coal in Kalimantan, Indonesia, to investigate the impact mentioned above through a quantitative method, which was performed directly in the field. The results show that the formed CO gas level ranged between 60.34 - 360.29 ppm, while the formed NO2 gas level ranged between 0.3 - 3.16 ppm, with average temperature and relative humidity of the blastholes at 31°C and 77.01%, respectively. Based on these results, the temperature and relative humidity conditions in the blastholes have a linear effect on the formation of toxic fumes by 84%. Considering the average wind speed at the measurement sites was 2.14 m/s, the trend of decreasing toxic fumes, time variables, and threshold limit values of exposure for humans of up to 15-minutes, it can be concluded that the safe time for workers to return to the site is less than 1 minute.
Aquifer Geometry Identification and Determination of Aquifer Storage and Recovery (ASR) in Bandung
Authors: Agustin F , Abdullah C I , Herlina D , Akhyar M F , Amukti R , Himawan B , Adiputra R N
Published: May 2023

Groundwater basins in Bandung city are included in the category of vulnerable areas to damage. It is interpreted that the Bandung area has damaged groundwater conditions. Geological conditions and soil in Bandung and its surroundings consist of alluvial layers of the eruption of Mount Tangkuban Perahu. The type of material in the north is generally a type of andosol. In the south and east of Bandung consists of a distribution of alluvial species with clay deposits and andosol soil types scattered in the central and western parts. This research was conducted to determine the hydrogeological and environmental conditions, groundwater level, pisometrics, aquifer characteristics, and water balance in the ASR Aquifer Storage and Recovery (ASR) wellbore. The research resulted in providing clean water that continues to be developed because of its effectiveness as a solution to overcome the groundwater crisis and groundwater level decline in the manufacture of ASR wells.
Slope Stability Analysis Using Bishop Method and Slide 2D Software at Sand Stone Mining in Sedau Village, Narmada District, Lombok Barat Regency
Authors: Gunawan M , Hidayati  , Adam R
Published: May 2023

Mining activities that involve constructing slopes will increase the potential for slope problems, especially those related to the increased potential for rock slope failure. Therefore, an in-depth study of the stability of the slope is required to determine the ability of the slope to stay stable without reinforcement or to choose the type of reinforcement that best fit a slope if it has a significant potential for landslides. This research aims to obtain the safety factor value of the sandstone mine slopes in Sedau Village, whether or not they comply with the safety requirements. Bishop’s method is employed to analyze the slip surface. Data processing is one of the requirements in Slide 2D Software to analyze slope stability based on material strength. The results of the safety factor obtained based on the analysis using the Bishop Method and 2D Slides are 1.671.
Biomass potential as an alternative resource for valuable products in the perspective of environmental sustainability and a circular economy system
Authors: Martini S , Kharismadewi D , Mardwita  , Ginting Y R
Published: May 2023

The increasing interest in environmental sustainability and its economic aspects has triggered scientific investigations on biomass’s potential as a new alternative source. Various fields like wastewater treatment, energy, construction material, and fertilizer are connected to biomaterial utilization. This review article discusses current literature related to the implementation of unused and low-cost biomass as either primary or supporting materials that could result in new products with higher economic value. Biomass consisting of plant parts such as rubber seed, eucalyptus bark, rice husks, fruit peels, or animal remnants like animal bones have been effective and potential for further processing. Furthermore, literature has shown that final products supported by or derived from processed biomass materials have potential competitiveness with other typical products entirely made from conventional sources like adsorbents, biofuel, concrete additives, and biofertilizers. After a comprehensive critical review of the relevant present literature, a concise summary can be drawn that biomass waste has reliability and potential function as an alternative resource to obtain low-cost materials for useful products making, and to overcome environmental damages due to increasing organic waste disposal.
Spectral And Fractal Analysis of Volcanic Tremor at Ijen Volcano, Indonesia
Authors: Wildani A , Maryanto S , Santoso D R , Triastuty H
Published: May 2023

A volcanic tremor is one of the seismic events that is usually recorded at the Ijen volcano. In 2014 the status of the Ijen volcano had yet to be declared normal after being critical in 2012. Many volcanic tremors are still recorded since then. This study aims at analyzing the volcanic tremors of Ijen volcano using the January to March 2014 seismic recording data obtained from the Center for Volcanology and Geological Disaster Mitigation, Bandung, Indonesia. We analyzed the spectra and fractal of volcanic tremors. Fractal and spectral analysis was conducted to investigate the dynamical system regarding the sources of the mechanism. Spectral analysis was estimated using the Fast Fourier Transform method, and fractal analysis was estimated using the regularization method. The spectra of a single volcanic tremor had frequencies of 1.1-1.5 Hz. Fractal analyzes were performed to identify dynamic systems. The fractal of a single volcanic tremor had a dimension of 2-2.3. Based on the frequency and fractal dimension values obtained, we suspect that the trigger of the volcanic tremors of the Ijen volcano is a fluid-filled crack mechanism.
Geochemical Characterization of Pit Wall Rocks: A Preliminary Step in Predicting the Water Quality of Pit Lake
Authors: Kusuma G J , Tuheteru E J , Badhurahman A , Pranoto K , Palinggi Y , Wahyudi H S , Pratama G R , Gautama R S
Published: May 2023

The quality of pit lake water during development and final condition is affected by various factors, including geochemical characterization of materials of a pit wall, which may consist of in-situ and backfilling materials. This research aims to obtain a geochemical characterization of pit wall materials using 3 main laboratory tests and analysis, namely static test, mineralogical and elemental composition analysis, and kinetic test using free draining column leach test. Static test results show that 5 of 6 samples exhibit low paste pH and NAG pH. Pyrite is found in four samples and is responsible for acid mine drainage production. Some samples contain acid-consuming carbonates and oxides such as calcite and periclase. Four samples exhibit leachates’ pH values lower than 3,00, mostly during all cycles. Alongside the lithostratigraphic distribution of pit wall rocks, these results imply a potential occurrence of acid mine drainage that will become a critical issue for water quality development and final condition in pit lake formation. Therefore, these results become essential feedback for the stakeholders to plan and implement acid mine drainage management to minimize the adverse impact of acid mine drainage in pit lakes. Immediate understanding of the geochemical characteristics of leachates from pit wall rock, which control the overall mine water quality.
Utilization of fly ash and bottom ash for tailings stabilization
Authors: Deni M C N , Kurniasari T
Published: May 2023

To anticipate the problem of acid mine drainage generation from the tailings, the experiments on the use of fly ash (FA) and bottom ash (BA) were carried out by considering the neutralizing potential contained in these materials. The basic characteristics of the tailings, FA, and BA materials were tested through mineralogy and geochemical test. Geochemical static tests were carried out on various compositions and rates of FA and BA mixtures added to the tailings. Based on the results of these tests and the results of the Toxicity Characteristic Leaching Procedure (TCLP) test, a kinetic geochemical test was carried out using a column to determine the neutralization performance of FA and BA. The results of the quality test of leachate water coming out from the column for 6 weeks test period showed that a mixture of FA and BA with a ratio of 9:1, which was added to the tailings at the rate of 15 kg/ton of tailings was the optimum mixture that could neutralize the acidity formed, and also reduced the Pb and Cu content in the leachate.
Environmental Improvement Policy through the obligation of post-tin mining reclamation in the islands of Bangka Belitung
Authors: Haryadi D , Ibrahim  , Darwance
Published: May 2023

Reclamation obligation is one way to ensure environmentally sound mining activities. Nevertheless, Bangka Belitung islands, which have been excavated for tin since 3 centuries ago, leave environmental problems behind due to poorly implemented reclamation obligations. Generally, Law Number 4 of 2009 on Minerals and Coal threatens this negligence with administrative sanctions such as written warnings, partial or complete suspension of permits, and even revocation. However, after almost 10 years in effect, these punishments have yet to be very effective in promoting reclamation optimization, including in Bangka Belitung. Therefore, a criminalization policy was implemented through the amendment of Law Number 3 of 2020 for the act of failure to perform reclamation and/or post-mining obligations and for not placing reclamation guarantees and/or post-mining guarantees with the punishment of imprisonment, fines, and additional criminal charges. Consequently, this normative study focuses on criminalization and its conditions, alongside the formulation of sanctions and punishments as part of criminal law policies. The formulation stage has a strategic role because it is the basis and initial indicator for judicial and executive policy implementation effectiveness.
The Impact of Sand Mining on the Socio-economic Community
Authors: Susanti F , Lestari S A P , Nugraha R F A
Published: May 2023

Regional Regulation No. 2 of 2012 concerning the Regional Spatial Plan for East Lombok Regency states that the Labuhan Haji sub-district is an area that has the potential as a mining area, one of which is in the Ijobalit sub-district. There is a mining area in Ijobalit village, which was established in 2006. The presence of mining will undoubtedly affect the socio-economic conditions of the people in Ijobalit Village. This study aims to determine the factors that influence the socio-economic conditions of the community in the sand mining area of Ijobalit Village, Labuhan Haji District, according to the perception of the surrounding community. This research is classified as a type of qualitative descriptive research. Sources of data needed were primary and secondary data with data collection methods: observation, questionnaires, interviews, and documentation. The analytical method used was scoring with a percentage and SPSS analysis. This study yielded six (6) socio-economic variables based on people’s perceptions that were affected by the presence of sand mining in Ijobalit, i.e. job opportunities, income, economic activity, social activity and infrastructure. One (1) socio-economic variable, i.e. conflict, was not affected by sand mining in Ijobalit.
Modelling and validation of laser based DED processes reinforced with nanoparticles in view of the effect of wetting
Authors: Zheng G , Rey P , Laqua R , Salgueiro M , Jakumeit J
Published: May 2023

Although the observation of wetting phenomena has a long history both in science and in everyday life, nanoscale wetting properties leave open a multitude of questions. Improving the properties of Direct Energy Deposition (DED) products through reinforcement with nanoparticles (NPs) is attractive. Due to the involved NPs, the wetting behaviour of the deposition differs from that in macroscales. Modelling and validation of a laser-based DED process reinforced with NPs in view of the effect of wetting is demonstrated in this study. Metal alloys reinforced with NPs (Ti6Al4V- and Al7075-TiC) are melted by laser light and deposit on a substrate. Heating of the alloys by laser light is tackled using a volumetric heat source model. A three-phase (solid, liquid and gas) melting and solidification simulation methodology is established in a continuum approach. Nanoparticles are treated in the Lagrangian framework. Effect of nanoparticle reinforcement on the wetting behaviour of melt bead during the printing process is investigated numerically, taking into account the influence of nanoparticles on contact angle and surface tension. Simulation results are compared with the experimental deposition of Ti6Al4V and Al7075 alloys through dimensional analysis of the tracks by macrography.
Optimization of powder catchment efficiency for industrial laser cladding processes
Authors: Grams Mitchell , Wood Gentry , Kamyabi-Gol Ata , Hamre Douglas
Published: May 2023

Laser clad overlays provide enhanced corrosion resistance and wear performance to components across a wide range of industries. Powder fed laser processes provide flexibility in material selection, however have traditionally yielded lower material usage efficiency (60–80%) compared to wire fed processes. A general model was developed to predict powder catchment efficiency based on the overlap between the molten pool and powder cloud distribution. Mathematical techniques of asymptotic analysis and blending were used to obtain closed-form expressions relating tabulated material properties and the key process inputs with the critical melt pool dimensions of leading length (xf) and maximum width (y
m). An improved experimental technique was implemented to measure the powder cloud distribution, a key process input which previously was not well understood. For baseline cladding conditions, melt pool dimensions were smaller than the powder cloud leading to catchment inefficiency. A custom laser optics module was designed to enable adjustment of the relative position of the melt pool and powder cloud independently from other process parameter changes. Combining optimized parameters with a shift of 1mm, catchment efficiency >90% has been achieved and sustained in production cladding operations. This work is part of a broader program at Apollo-Clad, using simple, accurate, and fast analytical modelling techniques to generate engineering design rules for laser-based processes.
Phase-field simulation of the formation of new grains by fragmentation during melting of an ABD900 superalloy
Authors: Böttger B. , Apel M.
Published: May 2023

Laser powder bed fusion (L-PBF) is an additive manufacturing method which involves local laser melting of powder particles, a partial remelting of previously deposited layers, and subsequent re-solidification under high thermal gradients and cooling rates. The transition between melting and re-solidification becomes visible as melt pool boundaries in optical micrographs and plays a crucial role: Apart from creating a strong segregation zone, the transition determines whether the microstructure is inherited and carried over to the next layer, or whether new grains with new orientations are formed. While heterogeneous nucleation is suppressed due to the lack of seeding particles at the small length scales inherent to L-PBF, alternatively, new grains can form via dendrite fragmentation, as demonstrated in this paper by phase-field simulations using the software MICRESS®. By strong coupling between the phase-field equation and a thermal 1D-cylinder approach for the long-range temperature field, consistency between latent heat and microstructure is ensured. To allow for a systematic variation of the orientation relationship between the dendrite growth direction and the respective temperature gradient, a two-step simulation procedure for two overlapping tracks with variable gradient directions is developed. Growth conditions which promote fragmentation and formation of new grains are analyzed and discussed.
Understanding conformal cooling in the diecasting of aluminum alloys
Authors: He Xin , Tang Chenglu , Vian Corey , Wong Chi-Seng , Juang Shuei-Wan , Vian Wei , Wang Xiaoming
Published: May 2023

Heat transfer and stress distribution are studied using computational fluid dynamic and structural simulation for a conformal cooling die insert made of Maraging M300 steel by selective laser melting. The phase transformation of cooling water is studied to understand the cooling effects and stress concentration on die life. The results of simulation are validated in production. The failure of the die insert has been revealed a result of enhanced stress concentration and corrosion directly related to the formation of vapor in the conformal cooling channel.
Computationally efficient model to predict the evolution in the thermal field in the EB-PBF and LP-DED processes
Authors: Pourabdollah P , Farhang Mehr F , Cockcroft S L , Maijer D M
Published: May 2023

Understanding the development of a number of defects found in components fabricated by the metal Additive Manufacturing (AM) processes requires an understanding of the evolution in the thermal field within the component at both the macro- and meso-scales. As a first step, in this work, the agglomeration method was used in combination with a time-averaged input of energy to simulate the macro-scale evolution in temperature. Two example processes: 1) laser-based powder-fed directed energy deposition; and 2) electron beam powder bed fusion, are used to demonstrate the modelling methodology. The approach employed focuses on ensuring the conservation of heat and is applied using ABAQUS. The two applications have been validated by comparing the predicted thermal behaviour with process-derived data. The results indicate that this method is an efficient strategy to predict the thermal field at the scale of the component being fabricated.
A phase field methodology for simulating the microstructure evolution during laser powder bed fusion in-situ alloying process
Authors: Li Z , Greenwood M , Phillion A
Published: May 2023

A recently-developed [1] multi-component phase field model has been utilized to investigate microstructure evolution during in-situ alloying of a blended elemental Ti-1Al-8V-5Fe alloy powder via the Laser Powder Bed Fusion process. The process of in-situ alloying, where elemental powder is used instead of pre-alloyed powder, was studied by performing two simulations having: (1) a uniform initial composition, and (2) a spatially varying initial composition to represent different powder particles. Specifically, the grain morphology, solute distribution, competitive growth and nucleation under the two different scenarios were simulated and compared. To assist the microstructure simulations, a macro-scale finite element model was developed to simulate the heat transfer during LPBF process. The thermal history data calculated by the finite element model was provided to the phase field model in order to simulate transient dendritic growth behaviour. The results show that a set of evenly-spaced columnar dendrites form in the uniform initial composition case, whereas when the initial composition is spatially varying, non-uniform dendrites having elongated shape can develop. It is also shown that competitive growth between dendrites is influenced by nucleation. For the spatially varying initial composition case, the results indicate that full alloying is difficult to achieve during the LPBF printing process; this incomplete alloying greatly influences the dendrite morphology and solute distribution.
Modulating Meltpool Dynamics and Microstructure using Thermoelectric Magnetohydrodynamics in Additive Manufacturing
Authors: Kao A , Tonry C , Soar P , Krastins I , Fan X , Lee PD , Pericleous K
Published: May 2023

Meltpool modulation in Selective Laser Remelting Additive Manufacturing via an oscillating magnetic field generates Thermoelectric Magnetohydrodynamics (TEMHD) flow. Numerical predictions show that the resulting microstructure can be significantly altered. A multi-scale numerical model captures the meso-scale melt pool dynamics coupled to microscale solidification showing the microstructure evolution and solute redistribution. The results highlight the complex interaction of the various physical phenomena and also show the method’s potential to disrupt the epitaxial growth defect. The model predictions are supported by preliminary experimental results that demonstrate the dependency of the melt pool depth on magnetic field orientation. The results highlight how a time-dependent field has the potential to provide an independent control mechanism to tailor microstructures.
Uncertainty quantification for computational modelling of laser powder bed fusion
Authors: Wells S , Plotkowski A , Coleman J , Rolchigo M , Carson R , Krane M J M
Published: May 2023

Additive manufacturing (AM) may have many advantages over traditional casting and wrought methods, but our understanding of the various processes is still limited. Computational models are useful to study and isolate underlying physics and improve our understanding of the AM process-microstructure-property relations. However, these models necessarily rely on simplifications and parameters of uncertain value. These assumptions reduce the overall reliability of the predictive capabilities of these models, so it is important to estimate the uncertainty in model output. In doing so, we quantify the effect of model limitations and identify potential areas of improvement, a procedure made possible by uncertainty quantification (UQ). Here we highlight recent work which coupled and propagated statistical and systematic uncertainties from a melt pool transport model based in OpenFOAM, through a grain scale cellular automaton code. We demonstrate how a UQ framework can identify model parameters which most significantly impact the reliability of model predictions through both models and thus provide insight for future improvements in the models and suggest measurements to reduce output uncertainty.