bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Investigation of Heat and Fluid Flow Characteristics through Steam Coil Air Preheater Installed in 100 MWe Utillity Boiler
Authors: Ariyanto E , Widodo W A 
Published: March 2021

Abstract
This paper study the flow characteristic through a set of tube bank used as air preheater in a 100 MWe utility boiler. The study using numerical simulation commercial Computational Fluid Dynamic (CFD) software. A 3D model uses to analyze the flow characteristics with 3 load variations. The model using a steady-state flow assumption. The Steam Coil Air Preheater modelled as a porous medium (PM) to represent its effect on the airflow through it. Porous Medium model can avoid a time consuming mess generation and simulation. This paper using an empirical equation to define inertial resistance coefficient (C2). The model using Heat Exchanger Model, Energy Model, and Realizable k -Epsilon for turbulence viscous model. 100%, 75%, and 50% load variation simulated with the model. The simulation result in both quantitative and qualitative data. The velocity and pressure distribution affected by the load variation, geometrical shape change, and tube bank set. Some secondary flow observed due to geometrical change along with the flow. The heat transfer characteristics observed with temperature distribution show that it affected by the flow characteristic.
Study of Non-condensable Gas, Fouling, and Plugging Effects on Condenser Performance Using NTU-Effectiveness Analytic Method and 2D Numeric Simulation
Authors: Tamimi H A , Prabowo  
Published: March 2021

Abstract
This paper was objected to determine the effect and how sensitive the variation of the percentage of non-condensable gas, fouling thickness and the amount of plugging to the performance of the condenser and the steam turbine power output. This study was conducted using the NTU-effectiveness analytical method, and specifically for the study of the effects of non-condensable gas combined with numerical simulations to obtain the value of the condensation heat transfer coefficient as an input for analytical calculations. The study was conducted with a variation of the percentage of non-condensable gas 0% (new and clean), 2%, 5%, and 8%, with fouling thickness 0 µm, 2 µm, 5 µm, and 8 µm, and the amount of plugging 0%, 5%, 10%, and 15%. 2D numerical simulation was used to determine the impact of non-condensable gas percentage variation on the value of the condensation heat transfer coefficient on the outside of the tube, both qualitatively and quantitatively along the circumference of the condenser tube. The results of this study were, the greater the percentage of non-condensable gas, the thicker the fouling layer, and the more amount of plugging, would have an impact on decreasing the net turbine work. Consequently for new and clean conditions, the percentage of non-condensable gas were 2%, 5%, 8%, fouling thickness 2 um, 5 um, 8 um, and the amount of plugging were 5%, 10%, 15%, resulting in net turbine work to 202.55 MW, 192.08 MW, 189.08 MW, 185.85 MW (non-condensable gas), 200.05 MW, 196.01 MW, 192.08 MW (fouling), 195.2 MW, 185.27 MW, and 174.77 MW (plugging). A financial loss simulation was also carried out due to the decline in electricity sales affected by the decreasing of power plant’s net turbine work.
The Effect of Decreasing Gas Turbine Flue Gas Temperature on The Performance of Muara Tawar Combined Cycle Power Plant
Authors: Muchlisin  , Darmawan Nastopo , Budi Setya 
Published: March 2021

Abstract
Muara Tawar combined cycle power plant consists of three gas turbines, three heat recovery steam generators and one steam turbine. An update of gas turbine blades in 2016 effected on decreasing gas turbine flue gas temperature by 8°C up to 20°C. This study aims to analyse the effect of decreasing gas turbine flue gas temperature on output power of steam turbine. The output power of steam turbines is simulated by using Cycle-Tempo software, based on combined cycle heat balance. Variations of decreasing gas turbine flue gas temperature are configured on three gas turbines, two gas turbines and one gas turbine. The result shows that every 2°C decrease in flue gas temperature of three gas turbines will decrease output power of steam turbines by 0.787%. Whereas if decrease in flue gas temperature of two gas turbines and one gas turbine will decrease output power of steam turbine by 0.532% and 0.267% respectively. Meanwhile, the simulation results show that the decrease in the output power of the steam turbine after update of the gas turbine blades, 72.8% is caused by a decrease in gas turbine flue gas temperature and 27.2% by other factors.
Gas Fuel Mixing to Reduce Elemental Sulfur Formations on Gas Regulating and Metering Stations in Muara Karang Steam Power Plant
Authors: Ericson F , Moulina R , Jayawardana P P 
Published: March 2021

Abstract
Muara Karang Steam Power Plant uses natural gas as a primary energy source. Gas supplied from three different suppliers, PHE, PGN, and NR. Each supplier has different gas quality because it sourced from different gas fields and processes. To feeds gas to the boiler in Unit 4 Muara Karang Steam Power Plant, it has gas regulating facilities to reduce the pressure of natural gas from 24 kg/cm2 to 4 kg/cm2. In 2019, Control Reducing Valve (CRV) opening climbs gradually although power output from Unit 4 is constant. Inspection of the strainer found that elemental sulfur formations occur, and a clogged strainer makes gas flow to the burner reduced. To compensate for elemental sulfur formation, a fuel mixing strategy was implemented. Before the fuel mixing strategy implemented, Unit 4 needs maintenance outage every three months with a CRV gas opening increase of 0.93%/day. After the fuel mixing strategy implemented, it needs maintenance outage every five months and CRV gas opening increase of 0.44%/day because elemental sulfur formation occurs slower. The fuel mixing strategy can save up to 11.7 billion rupiahs of outage cost.
A Study of Reducing Waste Heat Rejected By Condenser Using Thermoelectric Heat Pumps to Decrease Net Plant Heat Rate of Coal Fired Power Plant
Authors: Chandra Satriya Wibawa I G A , Yunus Qomarul Huda M , Wisyaldin M K 
Published: March 2021

Abstract
Paiton 1-2 subcritical coal-fired power plant applied coal switching program in order to can compete at Jawa-Bali electrical system. The calorific value of coal consumed is switched from 5200 kcal/kg to 4500 kcal/kg. As the result, it increases the net plant heat rate (NPHR) as well as the coal flow and produce more CO2 emissions. Increasing final feed water temperature can reduce NPHR because less heat needed to produce steam. One of promising method to increase feed water temperature is reusing wasted energy being rejected to environment through condenser. There is opportunity to reuse this waste heat by use of thermoelectric heat pumps (THPs). THPs convert electrical energy into thermal energy using Peltier effect. It can capture the heat released by condensation process and reused for increasing the feed water temperature, which can increase the cycle efficiency. Furthermore, it will reduce coal flow, decrease NPHR and aid the reduction of CO2 emissions. To maximize the energy recovery, a number of heat pumps can be used in series. This paper focused on finding the optimum number of heat pumps array. The expected feed water temperature rise gained from THPs arrangement is 19.81°C and potentially will contribute to 0.66% reduction on NPHR.
Repair of Cracked 150 MW High-Pressure Steam Turbine Rotor Coupling
Authors: Hapsoro A , Hanipa H , Grebinnyk K 
Published: March 2021

Abstract
A 150 MW high-pressure steam turbine rotor in Philippine experienced cracking in coupling area. The root cause of crack failure was investigated, and it was revealed that alignment setup design from original equipment manufacturer (OEM) contributed to the failure. The cracked coupling was restored by weld build up back to original dimension and new alignment target was recalculated and the result was counterchecked by finite element analysis (FEA) method to verify the stress level reduction.
CFD Modeling to Analyze Palm Shell Co-firing Percentage on Ketapang CFB Power Plant
Authors: Dian J , Saksono H D , Nugroho A 
Published: March 2021

Abstract
Biomass is one of the world’s greatest sustainable energy potentials. Utilization of biomass in the form of Co-firing coal fuel with biomass is one alternative to reduce the dependence of fossil fuels towards green power plant. This paper addresses Co-Firing modelling test results up to 50% biomass using palm kernel shell (palm kernel shell) in Ketapang Coal Fired Power Plant (CFPP) 2x10 MW. Ketapang CFPP has circulating fluidized bed (CFB) boiler. There are several advantages by using direct co-firing in CFB boiler: direct co-firing has the lowest investment cost, CFB has a wider range of biomass selection characteristics and characteristics than PC Boilers, CFB can process biomass materials with higher moisture content, etc. Result shown that the optimum percentage of palm kernel shell biomass use in the Ketapang Power Plant is 30% palm kernel shell. This is caused by the temperature value at 18 cm above the furnace bed and furnace exit gas temperature of 30% palm kernel shell which is not too much different from the temperature value at 18 cm above the bed furnace and furnace exit gas temperature of 0% palm kernel shell. This is also strengthened by the high value of the CO2 mass fraction in the 30% palm kernel shell mixture, which indicates that an ideal combustion.
Study of Economic Viability of Floating Photovoltaic Electric Power in Indonesia
Authors: Untoro A A , Gunawan T , Hidayanto B D , Perkasa F A , Wijaya A A 
Published: March 2021

Abstract
The government has already set target for utilisation of renewable energy to be achieved are at least 23% in 2025 and 31% in 2050. This study assesses the feasibility of the implementation utility scale Floating Solar PV in Indonesia based on technical and economic perspective. The analysis focused on the assessment of solar irradiation data, module efficiency to project electric production, followed by economic analysis on the parameter of the interest rate, debt to equity ratio, electric production, EPC Cost. In Indonesia, there is also incentives which are regulated to promote the infrastructure investment including renewable energy which are tax holiday, import tax exemption which can reduce the tariff. The investigation show that the effect the interest rate, debt to equity ratio, EPC Cost to the tariff and effect the incentive which are the tax holiday, import tax exemption to the tariff. which are evaluated for each area based on on assessment energy yield projection and dam identification to be compared to electrical generation cost (BPP Local and BPP National) where based on the simulation the electricity tariff of Floating Solar PV (4.9 – 5.8 cUSD/kWh) in each province is below the BPP
Effect of Rotational Speed on Microstructure and Optical Properties of Bismuth Ferrite Oxide (BiFeO3)
Authors: Iriani Y , Suryana R , Agustina E B 
Published: March 2021

Abstract
BiFeO3 films were deposited on quartz substrate using chemical solution deposition (CSD) and spin coating techniques with variations of rotational speed (1000 rpm, 2000 rpm, and 3000 rpm) and several films (4 layers and 8 layers). It characterized microstructure of films using X-Ray Diffraction (XRD), morphology, and cross-section using SEM and optical properties using UV-Vis. The results of characterization showed that an enhancement rotational speed causes the intensity of crystal field orientation to decrease, crystallite size, and crystallinity are the same. Surface morphology is getting smoother, flatter, lower porosity and the grain to be homogeneous with thinner thickness. Addition on the number of films causes higher intensity, crystallite size and crystallinity are the same. The film gets thicker, the morphology gets rough, and the boundaries between grains become clearer. Increasing the rotational speed and number of films causes the refractive index and extinction coefficient to be smaller. The light disperses measurement shows a linear relationship between photon energy and refractive index. Energy band gap generated between 2.2-2.5 eV.
Preliminary Investigation of NiO Anode for NCA/NiO Battery from Spent Catalyst Recovery
Authors: Nisa S S , Nurohmah A R , Yudha C S , Rahmawati M , Paramitha T , Widiyandari H , Dyartanti E R , Purwanto A 
Published: March 2021

Abstract
Spent nickel catalyst is the catalyst residue that has lost its catalytic function. Spent nickel catalyst contains Ni metal which is already high and environmentally hazardous. This problem can be solved by recovering the spent nickel catalyst as an anode and combined with lithium nickel cobalt oxide (NCA) as a cathode for lithium ion batteries. A study about it has never been conducted. The method used to treat the spent catalyst was acid leaching using 1 M citric acid and 4 M hydrochloric acid at 70-80°C for 2 hours, then continued with precipitation and thermal decomposition. Another method employed was direct sintering at 800°C for 12 hours. Material characterisation was carried out by X-Ray Diffraction (XRD), Atomic Absorption Spectrophotometry (AAS), Fourier Transform Infra-Red (FTIR), and X-Ray Fluorescence (XRF), while electrochemical performance was carried out by NEWARE Battery Analyzer and BTS software. The results of this study indicate that Ni can be recovered with hydrochloric acid as much as 15.387 gr higher than citric acid as much as 11.831 gr from 20 gr sample. The XRD pattern also indicates the presence of crystals NiO I and NiO II in the leached and sintered material. The results of acid leaching in the form of NiO I was perfectly formed, but NiO still has a little impurity. Electrochemical performance was tested with a cylindrical battery resulting in a discharge capacity of 37.210 mAh g−1.
Comparison of surface integrity, tool wear and chip morphology in CO2 cryogenic and dry milling of 304 stainless steel
Authors: Jabbaripour Behzad , Masouleh Hamid Souzani , Hadi Lavaei Salmasi M 
Published: March 2021

Abstract
In this study, dry and CO2 cryogenic milling conditions on 304 stainless steel is investigated. The cutting speeds of (60, 100, 140 m min−1), feed rates of (0.1, 0.13, 0.16 mm tooth−1) and axial depth of cuts of (0.5, 1, 1.5 mm) are considered in the L9 Taguchi array to design both dry and cryogenic slot milling tests. In cryogenic milling, defects in surface topography and tool wear (flank wear, built up edge and tool chipping) reduced significantly compared to dry machining conditions. Cryogenic milling improved the surface roughness from 4% to 71% compared to the corresponding dry conditions. In dry milling, more serrated chips and more discontinuities are seen in the lateral sides of the chips than cryogenic. In cryogenic compared to dry milling, the surface hardness of the workpiece decreased from at least 8% to a maximum of 12%. Also, the hardness of dry milling surface, increased from 43% to 102% compared to the bulk material. The maximum depth of hardening in cryogenic milling is 23% lower than that of dry condition. Increasing cutting parameters or dry machining will intensify the plastic deformation and compressing the microstructural grains adjacent to the machining surface, as in the deformed surface zone, the grain boundaries are indistinguishable. The maximum reduction in the thickness of the deformed layer was about 16% in the cryogenic milling compared to the corresponding dry condition. Considering XRD diagrams for dry and cryogenic milling compared to non-machined condition, no significant metallurgical phase transformation has occurred in the workpiece material.
Effects of new micro-pocketed bore surface topographies on the performance behaviours of aerodynamic journal bearing
Authors: Pattnayak M R , Pandey R K , Dutt J K 
Published: March 2021

Abstract
This paper presents the exploration for improving the static and dynamic performance behaviours of a self-acting rigid gas journal bearing employing some new conceived micro-depth pocketed surface topographies at the bore. The conceived micro-pockets comprise of relatively large size rectangular pocket having micro-depth at bearing bore in the converging zone followed by placing of different designs of sub-pockets at the trailing edge of the previous one in the direction of journal rotation. The form of equation achieved from Patir and Cheng’s model for the case of hydrodynamic lubrication regime and the related dynamic pressure equations have been solved using the finite volume method discretisation scheme followed by the solution of the algebraic equations using the Gauss-Seidel iterative method. The minimum film thickness, frictional force, side leakage, bearing dynamic coefficients, effective stiffness, effective damping, and critical mass parameters have been investigated with each new bore surface topography and compared with the performances of conventional aerodynamic journal bearing. Substantial improvements in both static and dynamic performances have been found with the new micro-pocketed bore surface topographies as compared to conventional one. Moreover, the established best bore design has produced significant increase (21%) in minimum film thickness, substantial reduction (12%) in coefficient of friction, and excellent improvement (170%) in the stability parameter (critical mass) as compared to the conventional case.
Deception and detection: the use of technology in assessing witness credibility
Authors: Bradshaw Robert 
Published: March 2021

Abstract
Tribunals, like courts, have long grappled with differentiating truthful from untruthful witnesses. A number of cases before the Court of Arbitration for Sport have considered whether polygraph evidence is admissible as a means of verifying witness testimony, though tribunals have not reached any consensus. Now, authorities in several countries are trialling a new generation of ‘lie detectors’ using technologies such as eye tracking, artificial intelligence, and brain imaging. Proponents argue that these new technologies are more accurate and less subjective than existing polygraphs and that they can transform the nature of witness evidence. This article outlines the potential scope of lie-detecting technologies in arbitration and their promise to revolutionize tribunals’ evaluations of witness credibility. It considers objections to their usage, including reliability, machine bias and privacy, and the privilege against self-incrimination, and concludes that considerations of fairness and proportionality favour excluding lie-detector evidence.
Enhanced Recovery After Surgery Protocol With Ultrasound-Guided Regional Blocks in Outpatient Plastic Surgery Patients Leads to Decreased Opioid Prescriptions and Consumption
Authors: Straughan David M , Lindsey John T , McCarthy Michelle , Legendre Davey , Lindsey John T 
Published: March 2021

Abstract

Background
Opioids are a mainstay of pain management. To limit the use of opioids, enhanced recovery after surgery (ERAS) protocols implement multimodal approaches to treat postoperative pain.

Objectives
The aim of this paper was to be the first to assess the efficacy of an ERAS protocol for plastic surgery outpatients that includes ultrasound-guided, surgeon-led regional blocks.

Methods
A retrospective review of patients undergoing outpatient plastic surgery on an ERAS protocol was performed. These patients were compared to a well-matched group not on an ERAS protocol (pre-ERAS). Endpoints included the amounts of opioid, antinausea, and antispasmodic medication prescribed. ERAS patients were given a postoperative questionnaire to assess both pain levels (0-10) and opioid consumption. ERAS patients anticipated to have higher levels of pain received ultrasound-guided anesthetic blocks.

Results
There were 157 patients in the pre-ERAS group and 202 patients in the ERAS group. Patients in the pre-ERAS group were prescribed more opioid (332.3 vs 100.3 morphine milligram equivalents (MME)/patient; P &lt; 0.001), antinausea (664 vs 16.3 mg of promethazine/patient; P &lt; 0.001), and antispasmodic (401.3 vs 31.2 mg of cyclobenzaprine/patient; P &lt; 0.001) medication. Patients on the ERAS protocol consumed an average total of 22.7 MME/patient postoperatively. Average pain scores in this group peaked at 5.32 on postoperative day 1 and then decreased significantly daily.

Conclusions
Implementation of an ERAS protocol for plastic surgery outpatients with utilization of ultrasound-guided regional anesthetic blocks is feasible and efficacious. The ability to significantly decrease prescribed opioids in this unique patient population is noteworthy.

Level of Evidence: 4
Characterization of 2 linear peptides without disulfide bridges from the venom of the spider Lycosa poonaensis (Lycosidae)
Authors: Megaly Alhussin M A , Yoshimoto Yusuke , Tsunoda Yugo , Miyashita Masahiro , Abdel-Wahab Mohammed , Nakagawa Yoshiaki , Miyagawa Hisashi 
Published: March 2021

ABSTRACT
Spider venom is a complex mixture of bioactive components, in which peptides play an important role by showing neurotoxicity or cytotoxicity. Disulfide-rich peptides are major components in the venom, but linear peptides without disulfide bridges are also present and often show antimicrobial activity. In this study, we analyzed the venom of the spider Lycosa poonaensis (Lycosidae) to find novel antimicrobial peptides using mass spectrometry. The result revealed that 120 out of 401 detected components were nondisulfide-bridged peptides. From them, the sequence of 2 peptides (lyp2370 and lyp1987) were determined by MS/MS analysis. The biological activity test revealed that lyp2370 has only weak antibacterial activity. On the other hand, lyp1987, which is identical to M-lycotoxin-Ls3b from the Lycosa singoriensi venom, showed significant antibacterial activity. The weak activity of lyp2370 was found to be due to the presence of a Glu residue on the hydrophilic face of its amphipathic α-helical structure.
Persistent spectral hypergraph based machine learning (PSH-ML) for protein-ligand binding affinity prediction
Authors: Liu Xiang , Feng Huitao , Wu Jie , Xia Kelin 
Published: March 2021

AbstractMolecular descriptors are essential to not only quantitative structure activity/property relationship (QSAR/QSPR) models, but also machine learning based chemical and biological data analysis. In this paper, we propose persistent spectral hypergraph (PSH) based molecular descriptors or fingerprints for the first time. Our PSH-based molecular descriptors are used in the characterization of molecular structures and interactions, and further combined with machine learning models, in particular gradient boosting tree (GBT), for protein-ligand binding affinity prediction. Different from traditional molecular descriptors, which are usually based on molecular graph models, a hypergraph-based topological representation is proposed for protein–ligand interaction characterization. Moreover, a filtration process is introduced to generate a series of nested hypergraphs in different scales. For each of these hypergraphs, its eigen spectrum information can be obtained from the corresponding (Hodge) Laplacain matrix. PSH studies the persistence and variation of the eigen spectrum of the nested hypergraphs during the filtration process. Molecular descriptors or fingerprints can be generated from persistent attributes, which are statistical or combinatorial functions of PSH, and combined with machine learning models, in particular, GBT. We test our PSH-GBT model on three most commonly used datasets, including PDBbind-2007, PDBbind-2013 and PDBbind-2016. Our results, for all these databases, are better than all existing machine learning models with traditional molecular descriptors, as far as we know.