bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, characterization, photoluminescent properties of carbon quantum dots and its applications in wastewater treatment
Authors: Nizam N U M , Hanafiah M M 
Published: May 2023

Abstract
Carbon-based nanomaterials are currently gaining attention in wastewater treatment. They have gained a prime position in membrane filtration to degrade pollutants. One of the most recent additions to the field of carbon-based nanomaterials is quantum dots (QDs). Due to their exceptional qualities, QDs are among the most promising carbon-based nanomaterials at the forefront of the wastewater treatment research field. Nonetheless, most quantum dots were not sustainably fabricated. Therefore, this study aims to evaluate the carbon-based carbon quantum dots derived from biomass wastes (rubber seed shells) where the properties, behaviour and photoluminescence characteristics were evaluated through several characterization analyses. The QDs were characterized using Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), field emission scanning electron microscope (FESEM) equipped with energy-dispersive X-ray spectroscopy (EDX), photoluminescence spectroscopy, zeta potential analyser and Raman spectroscopy. The morphological analysis revealed multi-layered planes with highly porous and uneven surfaces, consisting of a large number of oxygen-functional groups (hydroxyl, carboxyl, carbonyl). The mapping results showed a large uniform distribution of carbon and oxygen elements on the surface of QDs with a more signified composition of wt% carbon (72.4%) compared to oxygen elements, with 23.6%. The spectroscopic and photoluminescence studies confirmed the fabrication of high-quality carbon quantum dots with blue-greenish fluorescence emissions. These results have shown promising biomass-based QDs that can be applied in wastewater treatment based on their unique characteristics. Thus, the derived biomass-based QDs can be viewed as a promising and cost-effective adsorbent for wastewater and water treatment.
Oil Palm Health Estimation Using Low Altitude Remote Sensing
Authors: Jefri N S M , Ahmad A , Darwin N , Rasib A W 
Published: May 2023

Abstract
Unmanned Aerial Vehicle (UAV), Unmanned Aerial System (UAS), or drones are small autonomous airplane that does not need a pilot on board (CAR, 2016). UAS is increasingly becoming widely known for its capability to bring many innovations to the world. UAVs are also utilized as geospatial technology tools, providing benefits to environmental monitoring. Therefore, this study aims to estimate oil palm health using UAV payload remote sensing compact sensors. Two remote sensing compact sensors were used in this study which is visible (RGB) and Near Infrared (NIR) to get the reflectance curve of the oil palm. Analysing oil palm condition from reflectance curve by using a spectroradiometer are the first objective while analysing extraction oil palm condition by using sensors is the second objective. Some policy and regulation were involved to follow the guideline that has been implemented by the agency. Instead of using a UAV, the spectroradiometer was used to visualize the spectral response curve of an oil palm. As a result, the oil palm condition at study area is in healthy condition where the reflectance curve for multispectral compact sensors (0.84) and spectrometer (0.82) which are above healthy indicator (0.5) whereby favourable to determine the growth stability of oil palm trees. As a summary, these techniques are potential to support the development of modernization technology in environmental monitoring for oil palm plantations and give an alternative way to give good result on oil palm health condition.
Preliminary soil characteristics and growth performance of selected shrub plants for bio-engineering technique
Authors: Aznan M E , Rahman Z A , Tarmidzi S N A , Idris W M R , Lihan T , Khamis S , Kadir A A , Jalil N A A , Rahman M R A 
Published: May 2023

Abstract
This study presents the preliminary results of the physicochemical characteristics of the soil taken from the slope bio-engineering study. The soil would be used as a medium for the growth of selected shrub species namely Strobilanthes crispa (SC), Pseuderanthemum carruthers (PC), Tabernaemontana divaricata (TD), and Hibiscus rosa-Sinensis (HR). Soil medium was prepared in a 3:2:1 ratio (soil: organic fertilizer: sand). The plant-cutting technique was adopted and planted in polybags. The growth performance (height, number of leaves, chlorophyll, and leaf area) of these species was monitored on monthly basis up to three months. The result showed that the pH, organic matter and moisture content ranged from 4.15 to 5.23, 4.29% to 7.96% and 16.1% to 62.93%, respectively. The specific gravity and porosity of the soil ranged from 2.66 to 2.70 and 58.48% to 60.83%, respectively with clay loam and loam textures. SC and TD showed high mortality rates, with only 28% and 50% of the species still alive. However, the PC and HR had low mortality rates, with 98% and 96% of cuttings surviving, respectively. TD recorded the highest plant with 30.63 cm followed by HR (27.94 cm), PC (25.32 cm) and SC (22.36 cm). TD also recorded the highest number of leaves with 23 individuals. SC showed the highest leave area with a mean of 23.61 cm2 followed by PC (23.2 cm2), HR (14.43 cm2) and TD (13.28 cm2). HR recorded the highest chlorophyll content with a mean value of 46.62 followed by TD (45.23), SC (35.87) and PC (32.79). In conclusion, HR showed a good growth performance among the studied species. These preliminary findings suggested that all species have the potential to be used as biological material for slope erosion protection, with some soil treatment required for better growth outcomes.
Utilization of low-density emulsion to increase blasting efficiency and safety environment
Authors: Lubis J F , Handayana R H 
Published: May 2023

Abstract
The low-density emulsion was developed to replace ANFO, an explosive with weak resistance to water and tends to produce fume in the blasting process. Hanwha Mining Service Indonesia has developed low-density products with the brand Himex 70 LD. The base chemical emulsion uses the addition of a chemical as a gassing agent and a control gassing which can maximize the density of the emulsion up to 0.85 gr/cc. The stability of the emulsion is maintained by increasing the product’s viscosity. This study aimed to determine the performance of using low-density emulsion Himex 70 LD on the fragmentation, digging time, use of powder factor, and product stability against fumes. Based on project data, Himex 70 LD can produce optimal blasting results with a detonation value velocity reaching more than 4500 m/s. Himex 70 LD also reduces powder factor usage by up to 0.17 compared to pf usage in normal density emulsion with an average pf of 0.19. The resulting fragmentation size reaches 586.56 mm at 80% passing and digging time in the average range of 9.2 to 11.8 seconds. The low-density emulsion is also effectively stable even in wet holes and produces no yellow fume or zero NOX detonation.
Study of Flyrock to Reduce Safe Radius from 500 m to 300 m on Blasting Quarry at PT Vale Indonesia, Sorowako, Luwu Timur, South Sulawesi
Authors: Eko M R , Haris R H , Lubis J , Deri N P 
Published: May 2023

Abstract
Flyrock exceeding the safe radius can cause harm to equipment and humans. In recent years there has been frequent flyrock exceeding 500 m which has caused a significant impact on the environment in addition to several quarries adjacent to the population at a distance of 500 meters. Data collection at PT. Vale Indonesia uses Leica GS and GoPro with an analysis method using Tracker 5.1.5 to observe blasting activities. The estimated maximum flyrock trajectory distance is determined using empirical and dimensional analysis methods. It is done to obtain accurate and precise results on the conditions of the blasting sites. The empirical method is based on the theories of Lundborg (1981) and Richard and Moore (2005), while the dimensional analysis method is based on the theory of Ebrahim Ghasemi (2012). A comparison of the actual flyrock trajectory deviation between the dimensional analysis method of Ebrahim Ghasemi and the empirical method of Richard and Moore shows that Ebrahim Ghasemi’s method is closer to the deviation percentage, which is 7.76%. From the estimated distance, the flyrock closest to the actual flyrock dimension analysis method has a deviation of 4.89m with a factor of safety value against flyrock hazards of 1.5. A trial was conducted based on the dimensional analysis method to determine the appropriate safe radius.
The comparison of physical and mechanical properties of sand in Sedau and Obel-Obel Village
Authors: Firaz M F , Isfanari  
Published: May 2023

Abstract
The research was conducted in two regencies: Sedau Village in West Lombok Regency and Obel- Obel Village in East Lombok Regency. The two research sites are areas with potential sand wealth, with many sand mining companies operating. The sand mining company at the research site is expected to implement good mining practices which pay attention to mining design safety. Geotechnical recommendations on slope dimensions with a good safety factor value are required in making a mining design. Several factors affect a rock’s geotechnical properties. These factors are physical and mechanical. In this study, a comparison was made between the physical and mechanical properties of sand at two locations, which aims to compare rock characteristics and become a reference for geotechnical recommendations in the area. The research method used was sampling and testing in the laboratory. The results showed that the porosity value in Sedau Village was 0.102 and Obel-obel Village’s was 0.09. The average water content value in Sedau Village was 6.567%, and the average water content value in Obel-Obel Village was 8.233%. The specific gravity value of sand in Sedau Village was 3.75 gr/cm3, and that in Obel-obel Village was 3.75 gr/cm3. The compressive strength of sand in Sedau Village was 0.137 Mpa, and the compressive strength of sand in Obel-obel Village was 2.32 MPa. Based on the laboratory testing results, the influencing factors were analyzed, namely the location of its formation and the different processes of sand sedimentation in Sedau Village and Obel-obel Village.
Legal Protection for the Community Around the Sand Mining In Ijobalit Village, East Lombok Regency
Authors: Hartati W , Alpiana  , Ariyanto  
Published: May 2023

Abstract
Sand mining in Ijobalit Village, East Lombok district, is a mining activity carried out by people who own hilly land containing quarry materials such as sand. With this background, the community carries out mining by renting excavators to support their purposes. However, these activities come with many issues. This paper aims to determine the conception and provisions of mining in Indonesia and the legal protection for the community who carry out mining activities. The method used in this paper is normative legal research. The study results show that the conception and provisions of mining in Indonesia are inseparable from the utilization of natural resources and the sustainability of human and natural ecosystems. The sustainability of natural resources and human resources, can be assessed through licensing regulations and authorities as well as preventive protection. Licensing regulations and authorities means granting the community rights to natural resources use and management that are mutual control by taking damages caused by sand mining into account. And repressive protection means management efforts to more responsible sand mining businesses by developing an independent local business sector with guaranteed occupational safety. Occupational safety needs to be regulated technically through a permit to manage sand mining management.
General expressions for heat distribution, pressure, and current density in argon welding arcs
Authors: Villarreal-Medina R. , Delgado-Álvarez A. , Murphy A. B. , Méndez P. F. , Ramirez-Árgaez M. A. 
Published: May 2023

Abstract
In welding and wire-arc additive manufacturing (WAAM), a mobile arc is the heat source that enables the deposition of metals and the resulting properties of the final product. Because the arc involves temperatures of 20 000 K, and gas velocities of the order of 300 m/s, there are only a few experiments and models available to determine optimal, or at least acceptable, parameters for the operation such as current, voltage, and arc length. On the other hand, there is a lack of engineering guidance to optimize the processes resulting in costly and time-consuming trial-and-error optimization methods, which also involve wasteful use of energy and scrap parts. In this work, a numerical model of the gas-tungsten arc welding (GTAW) arc was created and validated against experiments. The model considers the arc interactions between a non-consumable electrode and the weld pool and accounts for multiple coupled heat transfer mechanisms: Joule heating, conduction, advection, radiation, and Thomson effect. The conditions considered cover the vast majority of GTAW welding operations. The results are generalized in the form of engineering expressions suitable to be embedded in metamodels, in which the heat source is just a part. Applications include penetration and width of welds and deposition rate in external-wire WAAM.
Understanding the inoculation of aluminium grains during welding under the influences of high cooling rate and high temperature gradient
Authors: Xu Yijiang , Kvam-Langelandsvik Geir , Bunaziv Ivan , Li Yanjun 
Published: May 2023

Abstract
Inoculation is an important method to generate fine equiaxed grain structures in alloys during solidification, which is widely used in shape casting and direct chill casting processes of aluminium alloys. Different from the normal casting processes, welding and additive manufacturing can have ultrahigh cooling rate and temperature gradient during solidification. This makes the grain refinement by inoculation method more difficult. Therefore, a deeper understanding on the influences of cooling rate and temperature gradient on the nucleation and growth of grains is necessary. In this work, a numerical model is developed to quantitatively address the above influences. The model has been successfully applied to predict the grain size in the welding of aluminium alloys as a function of locations.
Laser welding of dissimilar materials - simulation driven optimization of process parameters
Authors: Serdeczny M S 
Published: May 2023

Abstract
Laser welding can be used to join dissimilar materials to produce lightweight structures, and electric vehicle battery systems, which are important means of limiting the carbon emissions in the transport industry. Due to the differences in melting temperatures, thermal conductivities, and mutual solubility of dissimilar materials, it is still challenging to create defect-free joints with high mechanical strength, or low contact electrical resistance. In this work, we present a state-of-the-art numerical model of laser welding, developed within the Computational Fluids Dynamics (CFD) paradigm. The multi-physics model simulates melting, flow, and solidification of the alloys and accounts for the laser-material interactions, phase change, temperature and alloy-dependent thermophysical properties, recoil pressure, buoyancy force, and Marangoni effect. The simulation predicts weld penetration depth and width, alloy mixing, as well as the temperature gradient and cooling rate during the solidification that can be further fed into a micro-structure prediction model. The model is coupled with an optimization tool, which iterates over different process parameters to optimize the joint. The methodology is presented for steel to aluminium welding in lap configuration, but it can be used for other materials such as steel-copper, aluminium-copper, or steel-nickel, and in arbitrary geometrical configuration.
Enhancement of a quasi-analytical solution for modelling additive manufacturing processes
Authors: Cooke S. , Sinclair C. , Maijer D. 
Published: May 2023

Abstract
Numerical modelling methods (e.g. finite element) can provide accurate descriptions of long-range temperature fields in laser or electron-beam melting processes, however the high computational costs at part-scale make them unsuitable for process modelling in additive manufacturing (AM). Alternative methods such as semi-analytical solutions based on a moving heat source reduce the computational expense but at the cost of unrealistic assumptions. Radiation, temperature-dependent physical properties and latent heat are not considered in the semi-analytical approach but can have a significant effect on the thermal history. In this study, the error associated with each of these contributions are assessed against the conduction-only semi-analytical solution for a range of processing parameters for surface melting on solid Ti-6Al-4V. The semi-analytical model is then “enhanced” using results from finite element simulations to better account for the heat transfer in the AM process.
Measurements of deposition rate and droplet temperature in GMAW of aluminum alloys
Authors: Ramgopal Rishiekesh , Yan Zhaoyang , Scott Kevin S. , Chen Shujun , Mendez Patricio F. 
Published: May 2023

Abstract
This article explores the reason behind the higher deposition rate in Mg-containing aluminum alloys in gas metal arc welding (GMAW). Experiments performed on ER1100 (Mg-free alloy) and ER5183 (high Mg alloys) measured current, wire feed speed, and droplet temperature. A non-linear analysis of Joule heating at the electrode extension and an analysis of the power needed to heat the consumable to the droplet temperature were performed. Analysis revealed that Joule heating is two orders of magnitude smaller than what was necessary for the higher wire feed speed. The droplet temperature measurements were done for the first time for both consumables under identical conditions, which revealed that ER5183 had a lower droplet temperature than ER1100 by almost 350 K.
Arc length behaviour and voltage predictions for GMAW-Sp aluminum procedures in the Lincoln Procedure Hand Book
Authors: Eduardo Alvarez Rocha J. , Mendez Patricio F. 
Published: May 2023

Abstract
Heat input is a key component of a welding procedure, which is dependent on the several fall voltages composing a total voltage loss. As current practice is primarily reliant on trial and error to determine voltage settings for a desired heat input, a means to understand and predict the voltage loss is of interest to welding engineers. Voltage, amperage, and arc length measurements using ER4043 1.2 mm at varying voltages were used to break down fall voltage constituents for a given weld with GMAW-Sp. Arc length was defined as the distance from the weld pool to the point where the metal vapour and ionized gas boundary attach to the consumable, and measured over 5 droplet cycles to obtain a time average. Aluminum procedures in the Lincoln Procedure Hand Book (LPHB) with 1.2, 1.6, and 2.4 mm consumables were analyzed to predict the individual fall voltage constituents using experimental results. Expected arc lengths ranged from 13-26 mm depending on voltage prescribed in the procedure, and agreed with comparative experiments. Combined anode/cathode, and the arc column were major contributors to overall fall voltage with 64±3%, and 34±3%, respectively. Contact tip, electrode extension, and lead cables were minor contributors, each contributing less than 1.2% to the overall voltage loss.
Combined defect prediction for large-area die-cast components using high-resolution multi-phase simulation
Authors: Jakumeit J. , Behnken H , Laqua R , Gänz J. , Becker L. , Fehlbier M. , Middelmann O. 
Published: May 2023

Abstract
In the automotive industry there is a trend towards large components that are manufactured using high pressure die casting process (HPDC), in particular when many previously welded individual parts are to be replaced with one cast part to save costs and energy. In the case of large components, incipient solidification during mold filling cannot be ruled out. Casting defects due to cold running, air pockets and porosity cannot be separated spatially and temporally and influence each other. This stronger linking of the defects requires a realistic depiction of the casting process in the simulation, since the interactions between effects are more difficult to depict through approximations. The multi-phase approach presented here offers various options for this: The air is calculated as a compressible gas that is separated from the melt by a sharp boundary surface. Reduced melt flow due to solidification is represented by a porous media approach, followed by a complete flow stop at high solids. The formation of porosity due to volume shrinkage is coupled with a gas evaporation model. The multi-phase approach was validated by casting trials using a specially designed test geometry for thin-walled aluminum HPDC applications. First results of an industrial application are shown.
Predicting the local solidification time using spherical neural networks
Authors: Erber Maximilian , Rosnitschek Tobias , Bauer Constantin , Ali Güldali Muhammet , Alber-Laukant Bettina , Tremmel Stephan , Volk Wolfram , Hartmann Christoph 
Published: May 2023

Abstract
Castings are predestined for the application of structural optimization, but to date, the integration of process simulation into structural optimization is limited due to high computational cost and is therefore often neglected at the beginning of the design process. This leads to the need for surrogate models, which allow a fast and simplified evaluation of design proposals during the optimization in order to improve the integration. This article introduces a novel approach that estimates the solidification time of randomly created geometries solely based on the casting geometry. The approach uses ray-tracing methods to calculate the distance function along preset directions. The estimated solidification time is calculated using a Spherical Convolutional Neural Network (CNN). The training data is obtained by several thousand solidification simulations using the optimization toolkit of a commercial casting simulation software combined with further data augmentation. The model is experimentally validated for five different geometries in the sand casting process.
Meshless simulation of a macrosegregation benchmark considering the solid motion
Authors: Govže Viktor , Vušanović Igor , Šarler Božidar 
Published: May 2023

Abstract
We have extended the existing two-dimensional rigid solid phase benchmark for binary substance with the solid phase motion in the present paper. Incompressible laminar Newtonian flow is assumed, and a standard mixture formulation is used for the mass, momentum, energy, and solute transport. A coherency solid motion model accounts for the free-floating grains, assuming that the solid velocity is proportional to the mixture velocity and the liquid fraction. The lever rule is used to describe the mass fractions of the phases. A two-dimensional benchmark is solved using the semi-implicit meshless diffuse approximate method with an adaptive subdomain upwinding strategy. The results of the meshless method are compared to the finite volume method results with a reasonable agreement. The new benchmark results show that the solid motion has an essential effect on the macrosegregation pattern.