bluuebunny/crossref_metadata_2025 huggingface dataset:
Salary Benchmarking for Voice-Specialized Speech-Language Pathologists
Authors: Whiteside Catherine Blair , Kennedy Evan , Jetté Marie E.
Published: October 2024

Purpose:

This study aimed to understand how salaries of voice and upper airway–specialized speech-language pathologists (SLPs) differ from medical SLPs based on prevailing wage data and to give clinicians resources to better negotiate their salary and benefits.

Method:

A nationwide survey of voice-specialized SLPs was disseminated via various online platforms including American Speech-Language-Hearing Association Special Interest Group 3, Instagram, voice-specialized Facebook groups, and e-mail. Data were collected via REDCap. The survey investigates SLPs' salary, benefits, experience, clinical responsibilities, and profit generated through Current Procedural Terminology codes. Two separate analyses were completed. First, annual salary, as reported by participants, was compared against annual salary, as estimated by prevailing wage data. Second, a multiple regression driver analysis was completed to identify significant predictors of wage level within our sample. Outliers in the sample were removed using the Difference in Fits procedure.

Results:

A total of 111 participant surveys were included for analysis. Our data demonstrate that, between participant data and prevailing wage data, salaries for voice and upper airway disorders (VUAD) SLPs are significantly higher in the West, Midwest, and Southern regions. There is no significant difference in the Northeast. Several factors proved statistically significant predictors of increased salaries including years of work (
p
≤ .0001), cost of living (
p
= .0030), and work in multidisciplinary setting (
p
= .0223).

Conclusions:

As practitioners navigate negotiations for equitable compensation, leveraging localized salary data and emphasizing the value of specialized expertise may prove instrumental. Moreover, advocating for employer-sponsored professional development opportunities and benefits can enhance the overall well-being and professional satisfaction of VUAD SLPs, ensuring optimal delivery of care within this specialized field.
Smart forest monitoring: A novel Internet of Things framework with shortest path routing for sustainable environmental management
Authors: Etaati Alireza , Bastam Mostafa , Ataie Ehsan
Published: October 2024

Forests play a pivotal role in protecting the environment, preserving vital natural resources, and ultimately sustaining human life. However, the escalating occurrences of forest fires, whether of human origin or due to climate change, poses a significant threat to this ecosystem. In recent decades, the emergence of the IoT has been characterised by the utilisation of smart sensors for real‐time data collection. IoT facilitates proactive decision‐making for forest monitoring, control, and protection through advanced data analysis techniques, including AI algorithms. This research study presents a comprehensive approach to deploying a dynamic and adaptable network topology in forest environments, aimed at optimising data transmission and enhancing system reliability. Three distinct topologies are proposed in this research study: direct transmission from nodes to gateways, cluster formation with multi‐step data transmission, and clustering with data relayed by cluster heads. A key innovation is the use of high‐powered telecommunication modules in cluster heads, enabling long‐range data transmission while considering energy efficiency through solar power. To enhance system reliability, this study incorporates a reserve routing mechanism to mitigate the impact of node or cluster head failures. Additionally, the placement of gateway nodes is optimised using meta‐heuristic algorithms, including particle swarm optimisation (PSO), harmony search algorithm (HSA), and ant colony optimisation for continuous domains (ACOR), with ACOR emerging as the most effective. The primary objective of this article is to reduce power consumption, alleviate network traffic, and decrease nodes' interdependence, while also considering reliability coefficients and error tolerance as additional considerations. As shown in the results, the proposed methods effectively reduce network traffic, optimise routing, and ensure robust performance across various environmental conditions, highlighting the importance of these tailored topologies in enhancing energy efficiency, data accuracy, and network reliability in forest monitoring applications.
Revealing the state transition of Cen X-3 at high spectral resolution with Chandra
Authors: Sanjurjo-Ferrín G. , Torrejón J. M. , Oskinova L. , Postnov K. , Rodes-Roca J. J. , Schulz N. , Nowak M.
Published: October 2024

Cen X-3 is a compact, high-mass X-ray binary (HMXRB), likely powered by Roche lobe overflow. We present a phase-resolved X-ray spectral and timing analysis of a target of opportunity Chandra observation made during a low-flux to high-flux transition. The high-resolution spectra allow us to delve into the events that occurred during this episode. The spectrum is described by a single black body absorbed by a local column density of the order of 1023 − 24 cm−2, which is one to two orders of magnitude higher than found for previous analyses of data taken at similar orbital phases. Such a large column produces a Compton shoulder in the Fe Kα line. The transition appears to be caused by the onset of efficient cooling, which cools the plasma by 10 million degrees in just 10 ks, allowing matter to enter the magnetosphere. This happens after a major disturbance, probably the arrival of a train of wind clumps with individual masses in the range 1019 − 20 g. This train moves ballistically in an eccentric orbit around the NS, producing a distinctive Doppler modulation in the Fe XXV line.
Abnormal Stokes V profiles observed by Hinode in a sunspot
Authors: Hamedivafa H. , Rezaei R.
Published: October 2024

Context. Hidden magnetic components in a sunspot are present as small-scale structures that are absent in low-resolution observations.

Aims. We search for traces of the hidden magnetic components in spectro-polarimetric observations of a mature sunspot close to the disk center recorded by Hinode.

Methods. To find extra humps in the far blue and red lobes of Stokes V, we examined the sign reversal in the second derivative of the profile in the umbra and penumbra. We also looked for the hump signature in the Stokes I and the linear polarization profiles.

Results. The amplitudes of the humps are small compared to the main component. More than half of the profiles show one extra hump, while 21% show an extra hump on both the blue and the red lobe of the 630.15 nm line with the same magnetic polarity as the sunspot. The location of the pixels where the extra hump is seen on both lobes has a pseudo-grainy structure in the single wavelength Stokes V magnetograms. This type of profile is better detected in darker parts of the penumbra, as well as in the umbra-penumbra border toward the umbra. The spectral distance between the two humps averaged over elliptical rings levels off in the umbra, decreases toward the penumbra, and levels off again there. We find no correlations between the wavelength positions of the two humps.

Conclusions. We discuss two scenarios that could potentially produce the simultaneously observed blue and red humps: one in which a single hidden magnetic component is responsible for the two humps, and another in which the two humps emanate from two hidden magnetic components.
The star formation history of the first bulge fossil fragment candidate Terzan 5
Authors: Crociati C. , Cignoni M. , Dalessandro E. , Pallanca C. , Massari D. , Ferraro F. R. , Lanzoni B. , Origlia L. , Valenti E.
Published: October 2024

Context. Terzan 5 and Liller 1 are the only bulge stellar clusters hosting multi-iron and multi-age stellar populations. They are therefore claimed to constitute a novel class of astrophysical objects: the fossils of massive star-forming clumps that possibly sank to the center of the Milky Way and contributed to the formation of the bulge. This is based on the hypothesis that the ancient clumps were able to retain iron-enriched supernova ejecta, later giving rise to younger and more metal-rich populations.

Aims. A way to investigate this scenario is reconstructing their star formation histories (SFHs) and proving a prolonged and multiepisode star formation activity.

Methods. Leveraging ground- and space-based high-resolution images, we derived the SFH of Terzan 5 by employing the colormagnitude diagram fitting routine SFERA.

Results. The best-fit solution predicts an old, main peak occurred between 12 and 13 Gyr ago that generated 70% of the current stellar mass, followed by a lower-rate star formation activity with two main additional bursts.

Conclusions. These results indicate that Terzan 5, similarly to Liller 1, experienced a prolonged, multiepisode star formation activity, fueled by metal-enriched gas deposited in its central regions, in agreement with the expectations of a self-enrichment scenario in a primordial massive clump.
Equilibrium dynamical models in the inner region of the Large Magellanic Cloud based on Gaia DR3 kinematics
Authors: Kacharov Nikolay , Tahmasebzadeh Behzad , Cioni Maria-Rosa L. , van de Ven Glenn , Zhu Ling , Khoperskov Sergey
Published: October 2024

Context. The Large Magellanic Cloud (LMC) contains complex dynamics driven by both internal and external processes. The external forces are due to tidal interactions with the Small Magellanic Cloud and the Milky Way, while internally its dynamics mainly depend on the stellar, gas, and dark matter mass distributions. Despite this complexity, simple physical models often provide valuable insights into the primary driving factors.

Aims. We used Gaia Data Release 3 (DR3) to explore how well equilibrium dynamical models based on the Jeans equations and the Schwarzschild orbit superposition method are able to describe the LMC’s five-dimensional phase-space distribution and line-of-sight (LOS) velocity distribution, respectively. In the Schwarzschild model, we incorporated a triaxial bar component for the first time and derived the LMC’s bar pattern speed.

Methods. We fit comprehensive Jeans dynamical models to all Gaia DR3 stars with proper motion and LOS velocity measurements found in the footprint of the VISTA near-infrared survey of the Magellanic System using a discrete maximum likelihood approach. These models are very efficient at discriminating genuine LMC member stars from Milky Way foreground stars and background galaxies. They constrain the shape, orientation, and enclosed mass of the galaxy under the assumption of axisymmetry. We used the Jeans model results as a stepping stone to more complex two-component Schwarzschild models, which include an axisymmetric disc and a co-centric triaxial bar, which we fit to the LMC Gaia DR3 LOS velocity field using a χ2 minimisation approach.

Results. The Jeans models describe the rotation and velocity dispersion of the LMC disc well, and we find an inclination angle of θ = 25.5° ±0.2°, line of nodes orientation of ψ = 124° ±0.4°, and an intrinsic thickness of the disc of q0d = b/a = 0.23 ± 0.01 (minor to major axis ratio). However, bound to axisymmetry, these models fail to properly describe the kinematics in the central region of the galaxy dominated by the LMC bar. We used the derived disc orientation and the Gaia DR3 density image of the LMC to obtain the intrinsic shape of the bar. Using these two components as input to our Schwarzschild models, we performed orbit integration and weighting in a rotating reference frame fixed to the bar, deriving an independent measurement of the LMC bar pattern speed of Ω = 11 ± 4 km s−1 kpc−1. Both the Jeans and Schwarzschild models predict the same enclosed mass distribution within a radius of 6.2 kpc of ∼ 1.4 × 1010 M⊙.
Overviewing the emerging methods for predicting urban Sprawl features
Authors: Belinga Ange-Gabriel , El Haziti Mohamed
Published: October 2024

Urban sprawl, a common phenomenon characterized by uncontrolled urban growth, has far-reaching socio-economic and environmental implications. It’s a complex phenomenon, and finding a better way to tackle it is essential. Accurate simulation and prediction of urban sprawl features would facilitate decision-making in urban planning and the formulation of city growth policies. This article provides an overview of the techniques used to this end. Initially, it highlights the use of a certain category of so-called traditional methods, such as statistical models or classical machine learning methods. It then focuses particularly on the intersection of deep learning and urban sprawl modelling, examining how deep learning methods are being exploited to simulate and predict urban sprawl. I finally studies hybrid approaches that combine deep learning with agent-based models, cellular automata, or other techniques offer a synergistic way to leverage the strengths of different methodologies for urban sprawl modelling.
ETAP software based power flow analysis of 225/60/11KV substation in Tinghir
Authors: Stitou Hicham , Atillah Mohamed Amine , Boudaoud Abdelghani , Mounaim Aqil
Published: October 2024

Through technological advances, such as computer-based software, it is now possible to study and analyze complex electrical system problems and identify potential solutions. This analysis typically includes Load flow analysis (LFA), or power flow analysis (PFA). LFA is a crucial tool in power system engineering used for modeling and designing electrical power networks. It aims to determine the steady-state operating conditions of a power system to ensure a stable and efficient power balance between generation and load demands. LFA helps design robust power networks, maintains system stability, plans maintenance activities, and assists in the economic dispatch of power generation. This study focuses on modelling the 225/60/11 kV substation in Tinghir, a predominantly rural subdivision of the Drâa-Tafilalet region of Morocco. The model used data obtained from SPIE Maroc, specialists in industrial and tertiary electricity. AC and DC load flow analysis is performed on the Tinghir substation auxiliary services under two scenarios: one where the service equipment is powered by the auxiliary service transformer (AST) as the primary source, and another where the equipment supplied by a generator set due to a failure in the main power supply. ETAP software is selected for the simulation due to its advanced real-time power management capabilities and is widely used in power generation, transmission, and distribution systems. The Newton-Raphson method, known for its fast convergence and accuracy, is used for power flow analysis, making it ideal for complex systems. The results evaluate system performance under both normal and backup conditions, ensuring reliable operation of the auxiliary service installation at Tinghir’s substation.
Conventionalized impoliteness formulae in third-party assessments
Authors: Alvanoudi Angeliki
Published: October 2024

The paper examines the ideological work accomplished by the use of conventionalized impoliteness formulae in third
person reference, when the person being criticized or brought into disrepute is not present in the here-and-now of interaction.
Drawing on Interactional Linguistics and data from audio-recorded informal face-to-face Greek conversations, the study shows that
speakers mobilize conventionalized impoliteness formulae, along with other linguistic resources, in the course of third-party
assessments to evaluate sociocultural experience, and establish interlocutors’ shared negative affective stance toward the third
party picked on due to their national group membership. This practice reproduces everyday nationalism that unites offenders
against national ‘others’. The study enhances our understanding of the recontextualization of conventionalized impoliteness
formulae in talk-in-interaction, and the role of affective stance in the discursive formation of (national) identities.
Evaluation of different electrolytic solution composition on the microstructure and corrosion study on AZ31 magnesium alloy using PEO method
Authors: B Nagarajan , C Mathalai Sundaram
Published: October 2024

Magnesium (Mg) and its alloys are widely used in orthopedic implants due to their mechanical compatibility with bone tissue. However, their susceptibility to corrosion can compromise mechanical strength over time. The present study aims to enhance the corrosion resistance of AZ31 Mg alloy through Plasma Electrolytic Oxidation (PEO) coatings incorporating Hydroxyapatite (HAP). The effects of 5g of HAP in different electrolytic solutions—Sodium Silicate (Na2SiO39H2O) + Potassium Hydroxide (KOH) and Sodium Phosphate (Na3PO4) + Triethanolamine (C6H15NO3)—on the microstructure and corrosion characteristics were evaluated. The phase composition was analyzed using x-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS), while the surface morphology and cross-section of the coatings were assessed using Field Emission Scanning Electron Microscopy (FESEM). Corrosion studies were performed using Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) under Simulated Body Fluid (SBF) conditions. The results showed that the sample with the solution containing 5 g of HAP + Na3PO4 + C6H15NO3 (PS-2) exhibited superior anti-corrosion properties compared to the sample with 5 g of HAP + Na2SiO3·9H2O + KOH (PS-1). Notably, the cross-sectional analysis revealed significantly smaller pores in the PS-2 coatings. Among the two coated samples, the highest polarization resistance of 3.06 × 106 Ω·cm2 was observed for PS-1, while PS-2 showed a lower resistance of 2.9 × 106 Ω·cm2, correlating with their morphological characteristics. These findings suggest that sodium phosphate and triethanolamine improve biocompatibility when combined with pure AZ31 Mg alloy and HAP coatings.
Quasinormal modes and shadow of Schwarzschild black holes embedded in a Dehnen-type dark matter halo exhibiting a cloud of strings
Authors: Al-Badawi Ahmad , Shaymatov Sanjar
Published: October 2024

In this paper we consider a static spherically symmetric black hole (BH) embedded in a Dehnen-(1, 4, 0)-type dark matter (DM) halo in the presence of a cloud string. We examine and present data on how the core density of the DM halo parameter and the cloud string parameter affect BH attributes such as quasinormal modes (QNMs) and shadow cast. To do this, we first look into the effective potential of perturbation equations for three types of perturbation fields with different spins: massless scalar field, electromagnetic field and gravitational field. Then, using the sixth-order Wentzel–Kramers–Brillouin approximation, we examine QNMs of the BH disturbed by the three fields and derive quasinormal frequencies. The changes in QNM versus the core density parameter and the cloud string parameter for three disturbances are explored. We also investigate how the core density and the cloud string parameter affect the photon sphere and shadow radius. Interestingly, the study shows that the influence of Dehnen-type DM and cloud strings increases both the photon sphere and the shadow radius. Finally, we employ observational data from Sgr A⋆ and M87⋆ to set limitations on the BH parameters.
On the transverse-traceless gauge condition when matter is presented
Authors: Xue Yadong , He Xiaokai , Cao Zhoujian
Published: October 2024

The transverse-traceless gauge condition is an important concept in the theory of gravitational waves. It is well known that a vacuum is one of the key conditions to guarantee the existence of the transverse-traceless gauge. Although it is thin, the interstellar medium is ubiquitous in the Universe. Therefore, it is important to understand the concept of gravitational waves when matter is presented. Bondi–Metzner–Sachs theory has solved the gauge problem related to gravitational waves. But it does not help with cases when the gravitational wave propagates in matter. This paper discusses possible extensions of the transverse-traceless gauge condition to Minkowski perturbation with matter presented.
A Photometric and Astrometric Study of Open Star Clusters FSR-163 and Majaess 215 Using Gaia DR3
Authors: Ali Ola , Tadross A. L. , Osman A. I. , Hayman Z. M.
Published: October 2024

We have examined most of the astrophysical properties of the two star clusters, FSR-163 and Majaess 215, using the third data release of the Gaia space mission (Gaia DR3). We utilized the pyUPMASK method to allocate the probabilities of stars’ membership candidates. Using the clusters’ trigonometric parallaxes of the members with probabilities P > 50%, we calculated the distance to the clusters of 3290 (±140) and 2833 (±140) pc, respectively, which match well with our isochrone fitting results on the color–magnitude diagrams. We determined the age of the clusters, and they are 1.00 (±0.15) and 3.55 (±0.15) Gyr for FSR-163 and Majaess 215, respectively. We evaluated the following photometric parameters: reddenings, distances, galactic geometrical distances, luminosity–mass functions, and total masses of the two clusters. On studying the dynamic state of the two clusters, we found that Majaess 215 is more relaxed than FSR-163.
Breakthrough on Indonesia’s Energy Policy: Adaptive Governance Perspective for Just Energy Transition Partnership (JETP)
Authors: Wardhana A R , Aji P , Prasetyo K , Ma’rifatullah W H , Budiarto R
Published: October 2024

The Just Energy Transition Partnership (JETP) agreement strives to attain a peak emissions level of 290 Mt CO2eq by 2030 in the power sector while targeting a 34% renewable energy mix. To support these goals, a minimum of 20 billion USD from public sector pledges and private financial institutions is allocated for expedited decarbonisation. This entails retiring coal-fired power plants and concurrently developing renewable energy-based generation. However, implementing the JETP initiative encounters regulatory and technical challenges in Indonesia, arising from conflicting stakeholder interests, inconsistent regulatory frameworks, opposition from established incumbents of fossil fuels industries, and limited implementation capabilities. These barriers pose a significant threat to the efficacy and efficiency of the JETP program. Consequently, enhancing adaptive governance, namely, polycentricity, learning, diversity, deliberation, participation, flexibility, responsiveness, political support, and collaboration, is crucial to mitigate potential obstacles, bolstering the probability of success for the JETP program.
Organic Rankine Cycle System Design by Utilizing The Waste Heat of Internal Combustion Engine Based on Numerical Simulation
Authors: Nur Taufiq Bin , Putra Danil Wirandi
Published: October 2024

Most of the energy supply for today’s human activities still comes from fossil energy. Energy based on fossil fuels can cause an increase in greenhouse gas (GHG) emissions. Therefore, increasing the efficiency of energy conversion systems based on fossil fuels is necessary to mitigate pollutant emissions. The internal combustion engine (ICE) is one energy conversion machine that still consumes fossil energy to work in the transportation sector. Losses during internal combustion engine operation result in reduced engine thermal efficiency. Exhaust gas heat loss is one of the relatively significant losses. It leads to the waste of heat, which could be utilized and converted into valuable energy in the form of electrical energy that the engine can use, resulting in a considerable amount of primary fuel that could be saved. An organic Rankine cycle (ORC) system is considered in this analysis as a heat recovery unit from the Diesel ICE. The Aspen Plus simulation software was chosen to design the system consisting of an ORC unit integrated with a Diesel ICE unit. The working fluid for ORC used in this analysis is R-141B, R-123, and R-245fa. The simulation results show that the heat the ORC unit receives from the ICE via turbocharger is around 366 °C. Thus, the system has a thermal efficiency of 11.11% when using R-141B as the working fluid, 8.41% if R-123 as the working fluid, and 6.63% when using R-245fa as the working fluid. This study also obtained a condenser design as part of the ORC unit. The condenser can be considered a plate heat exchanger, with 53 plates needed to support the process.
Applying Gaussian Process Regression for Machine Learning-Assisted Reactor Simulations
Authors: Oktavian Muhammad Rizki
Published: October 2024

This study explores the integration of machine learning, specifically Gaussian Process Regression (GPR), into traditional reactor core simulations. Building upon previous work on Boiling Water Reactors (BWR), GPR is implemented to predict and correct errors in lower-fidelity simulation outcomes. The findings demonstrate significant improvements in prediction accuracy when GPR is coupled with the diffusion-based core simulator, exhibiting remarkable reductions in both keff
and nodal power errors. The comparison reveals that the GPR-enhanced core simulation model significantly outperforms both the standalone simulation and a combination of simulation with Multivariate Linear Regression. It also competes effectively with the performance of a Deep Neural Network-enhanced model. Importantly, this methodology enhances simulation accuracy while maintaining low computational costs. The research emphasizes the vast potential of machine learning, particularly GPR, in progressing nuclear reactor simulations, highlighting the immense value of combining traditional simulation methods with advanced statistical learning techniques.
Analysis of Regenerative Braking Energy Utilization in KfW i9000 Electric Trains on the Palur-Yogyakarta Operation
Authors: Darmawan Arief , Budiarto Rachmawan , Irnawan Roni
Published: October 2024

This study explores the potential assessment. of regenerative braking energy in the operation of Electric Multiple Units (EMU) on the Yogyakarta-Palur railway line, a 65.03 km. Prompted by a noticeable increase in passenger numbers in the Yogyakarta metropolitan buffer zone, the study calls for future energy management strategies, involving regenerative braking to reduce energy consumption. Utilizing a mathematical model implemented via MATLAB Simulink, the research encompasses complex train movement scenarios, considering variables such as acceleration values of 0.558 m/s2 and 1 m/s2, and deceleration values of -0.555 m/s2 and 0.36 m/s2. Speed limitations, travel patterns, and energy profiles are rigorously examined, along with incline influences, such as tangent angles of 0.0032 degrees and 0.0017 degrees. In segments like Purwosari-Solo Jebres, electrical energy consumption is quantified at 23.02 kWh, with regenerative braking energy at 1.42 kWh; in Maguwo-Brambanan, consumption is 15.28 kWh, with regenerative energy at 2.42 kWh. The peak power requirements and regenerative braking potentials were also determined, with values such as 619.9 kW and 225.7 kW, and 1785 kW and 198.2 kW respectively. The total electrical consumption for the routes from Palur to Yogyakarta and vice versa was found to be 325.52 kWh and 276.73 kWh, with energy recovery of 31.43 kWh and 26.6 kWh, and average energy recovery ratios of 9.66% and 9.61%.
Effect of Voltage Supply Unbalance on Vibration of Three-Phase Induction Motor
Authors: Kastawan I M W , Raharjo P , Kusumah R D , Kurnia M Z
Published: October 2024

The three-phase induction motor is the most popular electric motor used in industry. It has a simple and robust construction as well as a higher power density. It is a self-starting motor, therefore easier to start as compared to other types of electric motor. As the other benefit, a three-phase induction motor requires fewer maintenance measures. In order to maintain proper and continued operation, many parameters of a three-phase induction motor are constantly monitored. Among them is motor vibration. This is an important operation parameter frequently used to determine repair and maintenance needs to be taken on the motor. The vibration of a three-phase induction motor might be caused by mechanical as well as electrical problems. In this paper, the effect of magnitude unbalance of a three-phase voltage supply on the vibration of a three-phase induction motor is carefully investigated. To achieve this objective, two different laboratory experiments have been conducted. The first one is a three-phase induction motor supplied from a balance three-phase voltage supply. The second one is a three-phase induction motor supplied from an unbalance three-phase voltage supply. The unbalanced three-phase voltage supply condition is achieved by making the magnitude of one phase-voltage is 3%, 4%, and 5% lower than the magnitude of the other two phase-voltages. The vibration measurement is then taken in three different directions of the motor non-drive end (MNDE), i.e., horizontal (MNDEH), vertical (MNDEV), and axial (MNDEA). The experiment data show higher vibration in all directions, MNDEH, MNDEV, and MNDEA, as a load of the three-phase induction motor increases. Further, experiment data also show that higher vibration in all directions, MNDEH, MNDEV and MNDEA, is produced when unbalanced in magnitude voltage supply is higher
Water Turbine Guide Blades Effect of Quartz Sand on Abrasion Rate
Authors: Wirawan Tri Susilo , Firman Firman , Anshar Muhammad , Yunus Muhammad Yusuf , Noor Nirwan A.
Published: October 2024

Hydroelectric power plants with the aim of being used to generate electrical energy are mostly operated in areas with sedimentation content which can cause wear and tear on the components of the hydropower plant. This activity is emphasized to determine the effect of quartz sand on the rate of abrasion on the guide vanes of the Francis type water turbine. This activity was carried out using a water turbine guide blade abrasion test tool with a guide blade test object made of SUS 304 stainless steel material. The results are presented quantitatively and qualitatively, the greater the concentration and diameter of the quartz sand particles, the water pressure and the angle given at the same time, the greater the rate of abrasion that occurs in the francis type water turbine guide vane. The highest abrasion rate was 5.10 (g/cm2 x hour) in the angle variation test with a constant Q and a water: sand ratio of 70%: 30%.
Investigation of Vertical-axis Tidal Turbine Mechanical Strength using FSI Analysis based on Blade Profile
Authors: Ari Muhamad , Hadiwidodo Yoyok Setyo , Mukhtasor
Published: October 2024

Tidal energy, as a renewable energy source harnessed from the ocean, holds substantial promise owing to its heightened energy density, reliability, and longevity. An investigation encompassing the deployment of tidal stream electricity from 2003 through August 2020 revealed that blade malfunction was identified as the primary reason for system failures, with generator and monitoring system failures occurring subsequently. The majority of the research that has been done on the design of vertical-axis tidal turbine blades has focused on how well the blade performs in terms of power output without taking into account the generation of mechanical force. This force can potentially shorten the blade’s lifetime when implemented in a real-world scenario. By modelling a steady-state fluid-structure interaction (FSI) configuration, this study examines how the shape of the turbine blades affects the amount of mechanical force they generate, particularly in vertical-axis tidal turbines. The type of blade profile is the variable under consideration, and the stress levels experienced by a structure are influenced by the type of blade profile used. When comparing symmetrical and asymmetrical NACA straight blade types under similar climatic conditions, it has been found that the blade profile plays a significant role. Asymmetrical blade profiles, in particular, generate a higher lift force compared to symmetrical ones, thereby affecting stress levels more noticeably.
Optimization of Fuel Enrichment and Reactor Core Pitch Dimension in Hydride Microreactor using NSGA-II Method and OpenMC Calculation
Authors: Gusti A R P , Harto A W , Agung A
Published: October 2024

This study focuses on the design optimization of a hydride microreactor, aimed at supporting the equitable development of electricity in remote regions of Indonesia. Its compact design, inherent safety properties, and independence from the conventional electric grid make this microreactor concept suitable for electrifying even the most inaccessible areas. Current research investigates various aspects of the hydride microreactor design, employing a standard reactor core pitch dimension of 2.4 cm and fuel enrichment of 12%. It is crucial to operate the reactor using specific concentrations of Gadolinia burnable poison to enable a shutdown in the event of a stuck rod. By optimizing only the pitch dimension and fuel enrichment, the reactor can be simulated relatively quickly without the need for burnup calculations. Ideal configuration aims for lower enrichment, an extended fuel cycle, and a relatively low power peaking factor (PPF). The optimization process utilizes the Non-dominated Sorting Genetic Algorithm – II, with the neutron multiplication factor (keff) and PPF as primary objectives. Fuel cycle and feedback reactivity are the sub-objectives that are used to identify the optimal solution from the Pareto front. The calculation process of keff, PPF, fuel cycle, and feedback reactivity coefficients for specific pitch dimensions and fuel enrichment are done by utilizing the OpenMC Monte Carlo code. The optimal configuration is obtained through four generations of NSGA-II, featuring a reactor core pitch of 2.1 cm and fuel enrichment of 10.4%. This configuration yields a keff value of 1.0712049 and a PPF value of 2,0728 at the Beginning of Life (BOL). Remarkably, this configuration enables safe operation without using burnable poison for a continuous period of 12 years, generating 1 MW of thermal power. Emphasizing the reduction of fissile material is also essential to enhance the inherent safety of the reactor.
Computational assessment dose distribution of the antero-posterior and postero-anterior in Boron Neutron Capture Therapy for colorectal cancer
Authors: Putri S S , Harto A W , Sardjono Y
Published: October 2024

Colorectal is part of the gastrointestinal system that anatomically and physiologically, is excretory and extends throughout the abdominal region. In BNCT (Boron Neutron Capture Therapy) treatment for colorectal cancer, special projections are needed to ensure the dose is distributed effectively in cancer cells. Computational evaluation was carried out using PHITS 3.30 version, to determine the number of doses for organs at risk in the Antero-Posterior (AP) projection compared to the Postero-Anterior (PA) projection in this case, if the cancer cells are located in different parts, there are rectum and colon (transverse). BNCT treatment planning was designed using a female abdomen phantom voxel with the patient position Left Lateral Decubitus. Based on the simulation and evaluation results, it’s confirmed that isoeffective dose and irradiation time examined in the rectum is significantly reduced in the postero-anterior position so that postero-anterior and antero-posterior calculation results are 0.74 Gy and 20.61 Gy. However, if the cancer cells are in the transverse colon, antero-posterior projection is more effective for cases of colon cancer in the transverse colon of 0.71 Gy, and the postero-anterior projection with a dose of 29.15 Gy.
A Comparative Study on Picoammeter Designs as Alternatives for Nuclear Reactor Power Measurement Systems
Authors: Hanifasasti Alika , Bakhri Syaiful , Sukarman  , Helmi Fauzi R. , Septawijaya Gilang , Rankai Rasya P.
Published: October 2024

The study investigates the picoammeter, a highly sensitive current measurement device capable of measuring currents in the picoampere (pA) range. It discusses the typical amplification technique in picoammeters, utilizing an Op-Amp in a trans-impedance amplifier (TIA) circuit to convert the current into a voltage signal. The paper explores the impact of different IC Op-Amps on the picoammeter’s performance, evaluating AD549, MAX4230, LMC662, TLV272, and MCP6001. The result reveals that AD549 Op-Amp ICs are more suitable for picoammeter design due to their low noise performance and low input bias current. Noise output and AC stability are assessed through numerical analysis and simulations using a circuit simulator. The resulting picoammeter exhibits low noise, high sensitivity, and precise measurement accuracy, making it an optimal choice for precise low-current measurements in CIC detectors.
Integration methods: H3PO4 immersion and gamma irradiation exposure in modified activated carbon from banana (Musa paradisiaca L. sp.) stems biomass
Authors: Ariyanti Dhita , Saragih Renaldy Bernardo , Darojati Harum Azizah , Swantomo Deni , Permana Sidik , Pramutadi Asril , Wijaya Rio Natanael
Published: October 2024

Indonesia has abundant natural resources or tropical fruit like bananas (Musa paradisiaca L.sp.). Waste from natural resources can be identified as biomass. In Musa paradisiaca L.sp., biomass is derived from banana peels, stems, and leaves. This biomass can be used as activated carbon. Banana stems can be processed into activated carbon because they contain galacturonic acid. This a combine method of chemical activation via phosphate acid (H3PO4) immersion and gamma irradiation exposure to synthesize activated carbon from banana stems. These combined methods can make the surface area increase and make its function improve. Gamma irradiation exposure used variant doses 10 kGy, 30 kGy, and 50 kGy. Synthesized activated carbon was characterized using Teller Brunauer Emmett (BET) to analyze surface area of Activated Carbon and to identify the functional groups using Fourier Transform Infrared Spectroscopy (FTIR). The result shows the hidroxyl functional group decreases, and the transmission between irradiated carbons decreases with the increasing irradiation dose used. Effect of integration methods of acid immersion and gamma irradiation exposure on increasing surface area is enlarger of activated carbon banana stem. However, high-dose gamma irradiation exposure did not significantly impact surface area formation.
Feasibility Study of Rubber Seeds from North Sumatra, Indonesia as Biodiesel Feedstock; Production and Characterization
Authors: Tambunan Bisrul Hapis , Ambarita Himsar , Sitorus Tulus Burhanuddin , Sebayang Abdi Hanra
Published: October 2024

There are 5.5 million tons of rubber seeds produced annually on the 3.6 million hectares of rubber plantations that are located in Indonesia. Based on current estimates, 2.4 million tons of biodiesel may be produced if the rubber seeds are utilized as the primary raw material. Rubber seeds are a product of rubber plantations that have not been exploited; to obtain them, there is no need for new land or planting new trees. Rubber seeds are also non-edible, so their use does not conflict with foodstuffs. The purpose of this study was to assess the feasibility of rubber seed as a raw material for biodiesel and to produce and characterise biodiesel from rubber seed. The rubber seeds that have been collected from smallholder plantations in the northern Sumatra region of Indonesia are peeled to separate them from the kernels. Rubber seed kernels are boiled for 4 hours to separate the sap. Kernels that have been boiled are drained and then dried in the sun for 2 days in sunny weather. Kernels that had been dried in the sun were pressed using a screw press, and crude rubber seed oil was obtained. This crude oil is produced into biodiesel through degumming, esterification, and trans-esterification stages. Biodiesel production was carried out with variations in the catalyst ratios of 0.25, 0.5, 0.75, and 1, variations in the ratio of oil/methanol (w/v) of 1:1.25, 1:1.5, 1:1.75 (g/ml), and 1:2, variations in temperature of 50 °C, 60 °C, 70 °C, and 80 °C, and reaction times of 70 minutes, 80 minutes, 90 minutes, and 100 minutes. For each of these variables, the yield of biodiesel produced was calculated. Then the resulting biodiesel is characterised by testing its psychochemical properties against ASTM standards, which include calorific value, oxidation stability, viscosity, density, acid content, cetane number, and flash point. In the experiment on the effect of the amount of catalyst, the largest yield of 85% was obtained when the catalyst ratio (%v/v) was 0.75; in the investigation of the effect of the molar ratio of oil and methanol, the largest yield of 88% was obtained at a ratio of 1.75; the maximum yield of 85% was also obtained at a reaction temperature of 60 °C and 89% at a reaction time of 100 minutes. Almost all of the properties meet ASTM standards, except for the acid value of 0.53 mg KOH/g, which is 0.03 mg KOH/g higher, whereas according to the ASTM D6751-D 664 standard, the maximum acid value is 0.5 mg KOH/g.
Numerical Investigation of Vertical-Axis Hydrokinetic Turbine on Side-by-Side Configuration
Authors: Widyawan H B , Satrio D , Mukhtasor
Published: October 2024

Indonesia, a maritime country, has a renewable energy source that has not been utilized to date, which is ocean current energy, with a potential reaching 17.9 GW. Ocean current energy conversion can be harnessed by using a turbine. A turbine farm is one of the solutions that can be applied to harvest energy and utilize the full potential of the energy available. The arrangements of the turbine on a turbine farm become crucial because the wake generated may affect the performance of the turbines. In this study, numerical simulation will be carried out to find the best y/D distance for twin turbine in low-velocity ocean currents. The simulation is carried out using Computational Fluid Dynamics software with different variations of lateral spacing (y/D 1.2, 1.5, and 2.0). The performance of each turbine, such as torque and Cp, is obtained and compared to a single turbine arrangement. At y/D 1.5 peak Cp achieved at 0.45, a 53% increase from single turbine arrangement. Using a twin turbine arrangement may be beneficial in developing ocean current turbine farms in the future.
Techno-Economic Analysis of Utilization Offshore Platform in the Java Sea to Produce Hydrogen with Offshore Wind Turbine-Based Energy Sources
Authors: Franika Resistentio Vembre , Ridwan Muhhamad Kholid , Perdana Abram
Published: October 2024

Indonesia’s geographical condition, which consists of 70 percent ocean territory, holds the potential for utilizing offshore wind turbines to provide cleaner energy. In this study, economic calculations were conducted for offshore wind turbines to generate green electricity and green hydrogen. The chosen ocean area for this endeavor is around the Papa offshore platform in the Java Sea. This area has experienced an economic decline, making it viable for repurposing as a sub-station for a powerhouse and an electrolyzer plant. Based on meteorological data analysis results, the area around the Papa offshore platform exhibits an average at height of 119 m; the wind speed is 5.5 m/s.The prevailing wind direction is East Southeast (ESE), with a frequency of 25.2%. Further analysis of wind farms aimed at generating a capacity of 100.8 MW revealed an optimal potential energy generation of approximately 141,656.9 MWh per year. For scenario 1 (electricity production), the cost is $0.192/kWh. The levelized cost of hydrogen (LCOH) for scenario 2 (offshore electrolyzer) and scenario 3 (onshore electrolyzer) is $9.44/kg and $10.1/kg, respectively. To assess investment feasibility, a Net Present Value (NPV) analysis was conducted. This analysis yielded a selling price of electricity at $0.0271/kWh for the first scenario. For the second scenario, the selling price of hydrogen was calculated at $17.11/kg, and for the third scenario, it was $16.99/kg. Considering its flexibility and potential response to restrictions, the third scenario was deemed the most suitable for offshore utilization to produce clean energy.
Analysis of the Effect of More Fuel and Air Variations Excess Air on Combustion Process Simulation at a 10 kW Biomass Power Plant Using ASPEN PLUS
Authors: Ridwan Mohammad Kholid , Saptoadi Harwin , Afifah Nuha Amiratul , Akbar Ridwan Ali , Asy-Syahrani Maulana Alif
Published: October 2024

The utilization of biomass as an alternative energy can support the achievement of Net Zero Emissions. Each type of biomass fuel can provide different combustion effects from one another. This is due to the different heating values of each fuel. The calorific value is one of the things that affect the combustion performance of the biomass power plant. The main purpose of this study is to examine how different amounts of excess air used during the combustion process affect the outcomes. Combustion is a chemical reaction involving decomposition and gasification that simultaneously occurs in a space where a large amount of energy is released. The modeling and simulation of the decomposition and gasification processes were carried out using Aspen Plus. In this simulator, the decomposition process takes place in the Yields Reactor, while the gasification process occurs in the Gibbs Reactor. The biomass and ash components are characterized by their ultimate, proximate, and sulfur analysis. Then the excess air is varied to analyze its impact on the flame temperature from the reaction. The simulation findings emphasize crucial considerations for achieving complete combustion and reducing harmful gas emissions. Maintaining excess air close to the stoichiometric level ensures maximum combustion temperature at 1616.15 °C while minimizing excess air reduces NOx gas concentration. Approaching stoichiometric air level decreases CO gas and increases CO2, indicating more thorough combustion. However, excess air leads to lower adiabatic flame temperature due to nitrogen formation.
Unraveling the Sustainability Footprint: A Descriptive Analysis of Co-firing Technologies for Advancing Energy Transition in Indonesia
Authors: Budiarto Rachmawan , Novitasari Dwi , Izzati Ayesha Rida , Sari Wangi Pandan
Published: October 2024

Indonesia has ambitious renewable energy goals of achieving 23% utilization of renewable energy in primary energy mix by 2025 and 31% by 2050. To reduce emissions, the government plans to phase out Coal-Fired Power Plants (PLTU) by 2030 and adopt co-firing technology to decrease coal usage. Co-firing involves burning renewable materials alongside fossil fuels to reduce carbon emissions. However, concerns have arisen regarding this method’s sustainability, considering the environmental impact of various biomass sources. This research utilizes a descriptive analysis method to examine and assess the critical sustainability factors related to co-firing in Indonesia. While biomass can help mitigate GHG emissions, a comprehensive assessment of net emissions from the biomass process is crucial. Careful planning and policies for co-firing implementation are essential to mitigate negative effects and promote a greener future for Indonesia.
Experimental Study of Agglomeration Formation during Co-Combustion of Coal and Palm Kernel Shell in Fluidized Bed
Authors: Hidayat T , Budianto D , Kurniawati D , Pansawati I S , Saputra T F , Januardi R , Arnif I , Sulistyawati N E E , Sutardi T , Cahyadi
Published: October 2024

Co-combustion of biomass and coal in Indonesia power plants are a key element of the path towards achieving net-zero emissions. However, introducing biomass into a coal-boiler furnace may pose operational challenges. Therefore, this study aims to assess the potential of agglomeration when mixing biomass with a fluidized bed boiler. Complementation simulation tests were conducted by combining coal with various fractions of palm kernel shell (PKS) in a furnace capacity of 5kWth maintained at 850°C within an hour. The initial fuel was 100% coal, gradually increasing the biomass mixture by 5%, 10%, 15%, 20%, and 25%. The results indicated that de-fluidization occurred at 25% of the biomass mixture and to prevent agglomeration, the temperature of the bed was kept below 850°C. The agglomeration test of coal and PKS mixtures was successfully performed in a 5kW lab-scale facility, and the result will be useful for predicting agglomeration phenomena in power plants.