bluuebunny/crossref_metadata_2025 huggingface dataset:
Creep and Failure Behavior of Welded Joints Made of Alloy 617B
Authors: Udoh Annett , Speicher Magdalena , Klenk Andreas
Published: March 2024

Welded joints of Ni-base alloys are often the critical part of components operated under high temperature service conditions. Especially welds in thick-walled structures are susceptible to various crack phenomena. Creep rupture and deformation behavior of different similar welds of Alloy 617B, both circumferential and longitudinal, were determined in many research German projects with the aim to qualify the nickel alloys and its welded joints for the use in highly efficient Advanced Ultra Supercritical (AUSC) power plants. Damage mechanisms and failure behavior have also been investigated within these projects. In order to reduce the welding residual stresses in thick-walled components a post weld heat treatment (PWHT) for Alloy 617B is recommended after welding. This PHWT reduces not only residual stresses but causes changes in the damage mechanisms and failure behavior of welded joints of Alloy 617B. Improving effects of PWHT have been investigated in this study and results of microstructural investigations were correlated with the material behavior.
Seam Welded Alloy 740H Tube and Pipe for Advanced Power Systems
Authors: deBarbadillo John , Baker Brian , Gollihue Ronald , O'Donnell David , Shingledecker John , Purdy Daniel
Published: March 2024

Advanced power systems that operate at temperatures higher than about 650°C will require nickel-base alloys in critical areas for pressure containment. Age-hardened alloys offer an additional advantage of reduced volume of material compared with lower strength solid solution-strengthened alloys if thinner tube wall can be specified. To date, the only age-hardened alloy that has been approved for service in the time dependent temperature regime in the ASME Boiler and Pressure Vessel Code is INCONEL alloy 740H. Extensive evaluation of seamless tube, pipe, and forged fittings in welded construction, including implant test loops and pilot plants, has shown the alloy to be fit for service in the 650-800°C (1202-1472°F) temperature range. Since, nickel-base alloys are much more expensive than steel, manufacturing methods that reduce the cost of material for advanced power plants are of great interest. One process that has been extensively used for stainless steels and solution-strengthened nickel-base alloys is continuous seam welding. This process has rarely been applied to age-hardened alloys and never for use as tube in the creep-limited temperature regime. This paper presents the initial results of a study to develop alloy 740H welded tube, pipe and fittings and to generate data to support establishment of ASME code maximum stress allowables.
Investigation on Long-Term Fusion Boundary Microstructure and Damage Mechanism of Ex-service Dissimilar Metal Welds
Authors: Tokairin T. , Honda T. , Tokiyoshi T. , Honda M.
Published: March 2024

Metallurgical factors affecting the fusion boundary failure and damage mechanism of DMWs (Dissimilar Metal Welds) between the CSEF (Creep Strength Enhanced Ferritic) steels and austenitic steels were experimentally and theoretically investigated and discussed. Long-term exservice DMWs up to 123,000 hours were investigated; the precipitates near the fusion boundary were identified and quantitatively evaluated. Comparing with the other generic Ni-based weld material, MHPS original filler metal HIG370 (Ni bal.-16Cr-8Fe-2Nb-1Mo) showed superior suppression effect on fusion boundary damage of DMWs, which was verified by both of the microstructure observation and thermodynamic calculation. Based on the microstructure observation of crept specimen and ex-service samples of DMWs, temperature, time and stress dependence of fusion boundary damage of DMWs were clarified. Furthermore, fusion boundary damage morphology and mechanism due to precipitation and local constituent depletion was discussed and proposed from metallurgical viewpoints.
Microstructural Evolution and High Temperature Failure of T91/TP347H Dissimilar Welds Used in China Plants
Authors: Che Chang , Qian Gong , Yang Xishen , Liu Xiang
Published: March 2024

Dissimilar metal welds between T91 ferritic steels and TP347H austenitic alloys are commonly used in fossil power plants in China. Premature failure of such dissimilar welds can occur, resulting in unplanned plant outages that can cause huge economic losses. In this article, microstructural evolution of T91/TP347H dissimilar welds after different service conditions were studied, mechanical properties before and after service were also analyzed, a full investigation into the failure cause was carried out. The results show, the dissimilar metal welds in the as-welded condition consists of a sharp chemical concentration gradient across the fusion line, failure is attributed to the steep microstructural and mechanical properties gradients, formation of interfacial carbides that promote creep cavity formation.
Creep-Rupture Behavior of Alloy CCA617 Base Metal and Weldments under Advanced Steam Conditions
Authors: Shingledecker J.P. , Siefert J.A. , Santella M.L. , Unocic K.A. , Tortorelli P.F.
Published: March 2024

This paper presents results and analyses from long-term creep-rupture testing of alloy CCA617 (also known as alloy 617B) in wrought and welded forms at temperatures and stresses relevant to power generation under advanced steam conditions. The refined controlled chemical composition of CCA617 resulted in increased creep-rupture strength compared to the conventional alloy 617 chemistry at applied stress levels of ~150 MPa and above. Long-term creep rupture testing of weldments (in one case, over 100,000 h) showed that their creep-rupture lives were dependent on the welding process. Gas-tungsten-arc and shielded metal-arc weldments of CCA617 performed nearly equivalent to standard alloy 617 base metals in creep, but there was some debit in creep-rupture resistance when compared to CCA617 base metal. Submerged arc welding produced weldments that were notably weaker than both versions of alloy 617 base metal under creep conditions, possibly due to lack of optimization of filler wire composition and flux.
Research and Manufacturing of Waspaloy Alloy as Bolts and Blades for 700 °C A-USC Steam Turbines
Authors: Wang Yu , An Chunxiang
Published: March 2024

Research and development of 700°C A-USC steam turbine unit needs to be supported by materials with excellent overall performance. Waspaloy is a kind of γ′ phase precipitation hardening superalloy developed by the United States in the 1950s. In the 700°C R&D Plan of Shanghai Turbine Plant, it was selected as a candidate material for high temperature blades and bolts. The composition, microstructure, properties, blade die forging process and bolt rolling process of Waspaloy alloy were researched in this paper. Simultaneously, Shanghai Turbine Plant successfully manufactured Waspaloy alloy trial production for high temperature bolts and blades. The results show that Waspaloy not only has excellent processing performance, but also has good high temperature strength, long-term performance, stress relaxation resistance and long term aging performance stability at 700°C. It can fully meet the requirements of high-temperature blades and bolts of 700°C A-USC unit. It shows that the 700°C A-USC unit high temperature blades and bolts were successfully developed by Shanghai Turbine Plant.
Effect of Thermal Aging Treatment on Microstructure Evolution and Mechanical Properties Development in a Ni-Cr-Mo-V Weld Metal
Authors: Han Chaoyu , Li Kejian , Pan Jiluan , Cai Zhipeng
Published: March 2024

In this study, 25Cr2Ni2Mo1V filler metal was deposited to weld low pressure steam turbine shafts, which are operated in fossil power plants. A comparison experiment was conducted on the weld metals (WMs) before and after varied various aging duration from 200 hours up to 5000 hours at 350 ℃. Microstructure was characterized by means of scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD) techniques. In addition, mechanical properties of corresponding specimens were evaluated, e.g. Vickers microhardness, Charpy V impact toughness and tensile strength. It is shown that the tensile strength remained stable while impact energy value decreased with increasing aging duration. Based on the experiment above, it was concluded that the variation of mechanical properties can be attributed to the redissolution of carbides and reduction of bainite lath substructure.
Microstructural Characterization and Small Punch Creep Testing of 9-12%Cr Steel Weldments
Authors: Westraadt JE , Bernard D , Mphaphathi T , Bezuidenhout M
Published: March 2024

Small punch creep testing (SPCT) is a small-scale, accelerated creep test that allows for the determination of creep data using a limited amount of material. The question, however, remains how the data generated by this technique correlate to more established techniques such as uniaxial testing and ultimately to predictions regarding the remaining service life of a plant component. This empirical study investigated the microstructure-to-property relationship of welded 9-12%Cr steels as measured using SPCT. Virgin P91 (X10CrMoVNb9-1) steel was joined to service exposed X20 (X20CrMoV12-1) steel using two different filler materials (X20 and P91) via fusion welding. Site-specific samples were extracted from the parent plates, heat affected zones and weld metals using electro-discharge machining. Small punch creep testing were performed using a 276 N load at a temperature of 625°C. The untested sample microstructures were quantitatively characterized using a range of electron microscopy techniques to determine the precipitate (M23C6, MX) spacing, subgrain sizes and dislocation densities for each region of the weldments. Multiple linear regression analysis found that the subgrain size (λsg) played the largest contribution to the SPCT rupture life. The heat affected zones had the lowest SPCT rupture times (49-68 hours), which corresponded to the largest subgrain sizes (1.1-1.3 μm). The P91 parent plate material had the longest SPCT rupture time (349 hours), which corresponded to the lowest subgrain size (0.8 μm). The P91 weld metal sample showed lower initial deflection rates during the SPC testing, however the presence of non-metallic SiO2 inclusions in this zone contributed to accelerated brittle failure.
Study on Fractal Dimension of Grain Boundary as Creep Damage Index of Modified 9Cr-1Mo Steel
Authors: Nishimura Tatsuya , Negi Katsuki , Watanabe Kei , Hamasaki Kazuki , Tsumemaru Kouta , Mihahara Hiromi , Kawashima Fumiko , Fujiwara Kazuhito
Published: March 2024

Type IV creep damage of high chromium steel is a problem in thermal power plants and a method of evaluating remaining life is required. Type IV creep damage is characterized by many voids that initiate in the weldment fine grain heat affected zone (FGHAZ), where the stress multiaxiality (expressed by the Triaxiality Factor, TF) is high. As the creep continues, the shape of the grain boundary becomes simple; that is, close to a straight line. It is known that the grain boundary is fractal. The complexity of the fractal is represented by the fractal dimension. Therefore, we considered that the fractal dimension of the grain boundary in FGHAZ could be an indication of creep damage and studied its change as creep proceeded. First, creep tests were conducted to produce damaged materials, and their fractal dimensions were measured. Next, FEM analysis was conducted to obtain the distribution of the principal stress, TF, and creep strain of the observed surface. The distribution of creep damage was obtained by the time fraction rule. The results of this evaluation confirmed that the fractal dimension of the grain boundary decreases with creep time and that the principal stress and TF affect it.
Study on Quantitative Relation between Stress and Stress Multiaxiality and Initiation Rate, Growth Rate, and Initiation Start Time of Voids in Type IV Creep Damage of Modified 9Cr-1Mo Steel
Authors: Hamasaki Kazuki , Nishimura Tatsuya , Watanabe Kei , Negi Katsuki , Tsumemaru Kouta , Miyahara Hiromi , Kawashima Fumiko , Fujiwara Kazuhito
Published: March 2024

Type IV creep damage is a problem in high-temperature steam piping made of high chromium steel at thermal power plants, and a method for evaluating the remaining life is required. In this study, we considered that void’s initiation and growth can be expressed by initiation rate f, growth rate h, and initiation start time t1, and that stress and TF affect f, h and t1. We also proposed the method to estimate f, h and t1 by measuring the change of the distribution of radius of voids during creep test. The creep test conditions are (1) test temperature of 650 C, maximum principal stress σ1 of 79.5MPa, and TF of 2.5 ~ 3.0, and (2) test temperature of 650C, maximum principal stress of 71.5MPa, and TF of 2.5 ~ 3.0. The influence of σ1 to f, h and t1 was quantified by comparing the result of test (1) and that of test (2).
Deformation Behavior of Advanced γ-TiAl Based Alloys by In-Situ SEM Observation and Digital Image Correlation Technique
Authors: Okada Yotaro , Yamagata Ryosuke , Nakashima Hirotoyo , Takeyama Masao
Published: March 2024

Tensile deformation behavior of γ-TiAl based alloys consisting of α2-Ti3Al/γ lamellar colonies, β-Ti grains, and γ grains were investigated by in-situ scanning electron microscopy and digital image correlation technique, in order to identify the role of each microstructure constituents in deformation. The alloy with nearly lamellar microstructure, in which the volume fraction of β/γ duplex (VDP) is 10%, shows elongation of only 0.14%, whereas the alloy with nearly globular β/γ duplex microstructure with VDP of 94% shows elongation of 0.49%. In α2/γ lamellar microstructure, obvious strain localization occurs along lamellae and develops at specific regions with loading. In the case of β/γ duplex microstructure, strain localization is observed in γ grains and in β phase regions near the β/γ phase boundary, although no obvious deformation is observed in the β grains. β/γ phase boundaries enhances room temperature ductility of TiAl alloys by inducing multiple slip in γ phase and deformation of β phase.
Effect of Carbon in Solution on Phase Equilibria among β/α(α2)/γ Phases in TiAl Alloys Using Soft X-Ray Emission Spectroscopy
Authors: Kimoto Yuta , Nakashima Hirotoyo , Takeyama Masao
Published: March 2024

Interstitial carbon (C) in β-Ti, α-Ti, α2-Ti3Al and γ-TiAl phases present in the γ-TiAl alloys with and without substitutional elements (M: transition element) is quantitatively analyzed using soft X-ray emission spectroscopy (SXES), in order to reveal the effect of solute carbon on the phase equilibria. SXES for carbon analysis was used and the peak intensity of the second reflection of carbon Kα is analyzed using the fully homogenized sample having different C content under the optimum condition to make the accurate calibration curves. The obtained calibration curve is in an accuracy of ± 0.07 at. % C. In all heat treated alloys, no carbide is observed. In Ti-Al binary system, the α+γ phase region shifts toward higher Ti side, and the volume fraction of γ phase increases slightly with the carbon addition. In all system, carbon preferentially partitions into the α phase, followed by less partitioning in the γ and β phases in order. The carbon content in the β phase remains unchanged of almost 0.05 at. % regardless of carbon addition in Ti-Al-V system and the partition coefficient of carbon between the α and γ phases becomes larger in Ti-Al-V system than that in TiAl binary system.
Experimental and Computational Study on Grain Boundary and Grain Interior Precipitation of Fe2Nb Laves Phase in Fe-Cr-Ni-Nb Austenitic Heat Resistant Steels
Authors: Kikuchi Kenta , Nakashima Hirotoyo , Takeyama Masao
Published: March 2024

The precipitation behavior of various phases in austenitic heat-resistant model steels, including the Fe2Nb Laves phase (C14 structure) on grain boundaries (GB) and grain interiors (GI), and the Ni3Nb metastable γ“ phase and stable δ phase on GI, was investigated through experimental study at different temperatures and thermokinetic calculation. The steel samples were prepared by arc melting followed by 65% cold rolling. Subsequently, the samples were solution treated within the γ single-phase region to control the grain size to approximately 150 μm. Aging of the solution-treated samples was carried out at temperatures ranging from 973 K to 1473 K for up to 3600 hours. Microstructural observations were conducted using FE-SEM, and the chemical compositions of the γ matrix and precipitates of Laves and δ phases were analyzed using EPMA. The precipitation modeling was performed using MatCalc software, utilizing a thermodynamic database constructed by our research group to calculate the chemical potential of each phase. Classical nucleation theory was applied for nucleation, while the SFFK model was employed for the growth and coarsening stages. Distinct phases were defined for grain boundary and grain interior Laves phase, with all precipitates assumed to have spherical morphology in the calculations. The precipitation start time was defined as the time when the precipitate fraction reached 1%. Experimental results indicated that above 973 K, Laves phase nucleation primarily occurred on grain boundaries before extending into the grain interior, with the nose temperature located around 1273 K. To replicate the experimentally determined Time-Temperature-Precipitation (TTP) diagram, interaction parameters among elements were adjusted. Additionally, by introducing lower interfacial energy between the γ matrix and Laves phase, the TTP diagram was successfully reproduced via calculation, suggesting relative stability at the interface.
Effect of Widmanstätten-Type α2-Ti3Al Plates on Creep in γ-TiAl Based Alloy
Authors: Ikemura Fumiya , Wakabayashi Hideki , Yamagata Ryosuke , Nakashima Hirotoyo , Takeyama Masao
Published: March 2024

In this study the effect of Widmanstätten-type morphology α2 plates on creep has been investigated by preparing nearly equiaxed γ (Nγ) and nearly equiaxed γ having Widmanstätten-type α2 plates within grain (Wα2). Creep tests were conducted at 1073 K under constant stresses, high stress and low stress, in air. At the high stress, Wα2 shows creep rate smaller than Nγ in transient stage, both specimens show similar minimum creep rate and the creep strain at minimum creep rate is 3 % for Wα2 and 10 % for N γ, since N γ shows prolonged primary region. In acceleration stage, both show similar behavior with rupture time of about 50 h and rupture elongation of 60 %. At the low stress, on the other hand, reverse behavior occurs, that is, W α2 shows creep rate higher than Nγ in transient stage. The regions near grain boundaries progressively deformed for both specimens at high stress level, whereas deformed region is extended within grain interiors. From these results it is suggested that α2 plate act as the obstacle for dislocation motion in the γ matrix at high stress and that interfacial dislocation promote the creep deformation at low stress.
Novel Microstructure Design Approach Using TCP and GCP in Ni-Cr-M Ternary Systems Based on Phase Diagram Study at Elevated Temperature
Authors: Nagashima Ryota , Yamagata Ryosuke , Nakashima Hirotoyo , Kobayashi Satoru , Takeyama Masao
Published: March 2024

Strengthening of Ni-based superalloys is in principle designed using GCP (Geometrically Close-packed phase) of Ni3Al-γ' (L12). However, game-changing microstructural design principle without relying on γ' phase will be needed for further development of the alloys. We are currently constructing a novel microstructure design principle, using thermodynamically stable TCP (Topologically Close-packed phase) for grain boundaries, together with GCP other than γ' phase for grain interiors, based on grain boundary precipitation strengthening (GBPS) mechanism. One of the promising systems is Ni-Cr-Mo ternary system, where TCP of NiMo (oP112) phases, μ (hR13) and P (oP56), together with GCP of Ni3Mo (oP8) and Ni2Cr (oP6) exists. In this study, thus, phase equilibria among A1 (fcc)/TCP/GCP phases in Ni-Cr-Mo and Ni-Cr-W systems have been examined at temperature range from 973 K to 1073 K, based on experiment and calculation. In Ni-Cr-Mo system, Ni2(Cr, Mo) with oP6 Pearson symbol, which is stable at about 873 K in Ni-Cr binary system, is formed to exist even at 1073 K. oP6 phase is coherently formed in A1 matrix with a crystallographic orientation of {110}A1 // (100)oP6, <001>Α1 // [010]oP6, indicating GCP at composition range around Ni-15Cr-15Mo as island. In Mo-rich region there is Α1/NiMo/oP6 three-phase coexisting region, whereas another three-phase coexisting region of Α1/P/oP6 exists in Cr-rich region. Based on vertical section, it is possible to design microstructure with TCP at grain boundaries, together with oP6 phase within grain interiors by two-step heat treatment.
Primary Creep and Stress Relaxation Behavior Modeling of a Steel for Turbine Applications
Authors: Maldini M. , Donnini R. , Ripamonti D. , Riva A.
Published: March 2024

A constitutive equation, with parameters derived from the interpolation of primary and steady state stages of constant load creep curves, has been utilized to estimate the stress relaxation behavior of the martensitic steel X20Cr13, alloy used in many high temperature applications, including heavy duty gas turbines. Creep and stress relaxation tests have been performed at 350°C, close to the negligible creep temperature of the studied alloy for stresses of interest for engineering applications. The creep tests were carried out at stresses below and above the yield stress, whereas, for the relaxation stress tests, the imposed strain was in the range 0.2% to 1.2% with the purpose to have, at the beginning of the tests, the same initial stresses of the performed creep tests. After a stress relaxation period, lasting between 10 to 1000 hours, each specimen was generally reloaded at the initial stress and a new relaxation test, on the same specimen, was carried out. This “reloading procedure”, simulating the re-tightening of bolts, has been repeated several times. The proposed equation has shown to well predict the experimental creep and stress relaxation behavior of the steel under investigation.
Stability of Ordered B2-βo and Disordered bcc-β Phases in TiAl—A First Principles Study
Authors: Pyczak Florian , Kononikhina Victoria , Stark Andreas
Published: March 2024

Either at higher temperatures or when a certain alloying element content is exceeded, γ-TiAl alloys contain the β phase (bcc) or its ordered derivate βo (B2). The relatively soft β phase can facilitate hot deformation, but βo is detrimental for creep strength and ductility. Thus, knowledge about βo→β phase transformation is desirable. Surprisingly, for the binary Ti-Al system it is under discussion whether the ordered βo phase exists. Also, the effect of alloying elements on the β phase ordering is still unclear. In the present work the ordering of the β phase in binary Ti-(39,42,45)Al and ternary Ti-42Al-2X alloys (X=Fe, Cr, Nb, Ta, Mo) which was experimentally investigated by neutron and high energy X-ray diffraction is compared with the results of first principles calculations using density functional theory. Except for Cr the experimentally determined and the predicted behavior correspond.
700℃ A-USC Technology Development in Japan
Authors: Fukuda Masafumi , Yagi Yutaka , Fukutomi Hiroyuki , Nishinoiri Satoshi , Sato Katsura , Nishii Toshiaki , Nishimaki Kojiro , Takano Tetsu , Aoki Hiroshi , Okuma Yoshitomo , Furukawa Takashi , Shimada Masahiko , Saito Nobuhiko , Hashimoto Keita , Kitamura Masaki , Saito Eiji , Semba Hiroyuki , Matsubara Yoichi , Takahashi Koichi , Takahashi Takeo , Suga Takeo
Published: March 2024

CO2 emission reduction from coal power plants is still a serious issue to mitigate the impact of global warming and resulting climate change, though renewables are growing today. As one of the solutions, we developed A-USC (Advanced Ultra Super Critical steam condition) technology to raise the thermal efficiency of coal power plants by using high steam temperatures of up to 700℃ between 2008 and 2017 with the support of METI (Ministry of Economy, Trade and Industry) and NEDO (New Energy and Industrial Technology Development Organization). The temperature is 100℃ higher than that of the current USC technology. Materials and manufacturing technology for boilers, turbines and valves were developed. Boiler components, such as super heaters, a thick wall pipe, valves, and a turbine casing were successfully tested in a 700℃-boiler component test facility. Turbine rotors were tested successfully, as well, in a turbine rotating test facility under 700℃ and at actual speed. The tested components were removed from the facilities and inspected. In 2017, following the component tests, we started a new project to develop the maintenance technology of the A-USC power plants with the support of NEDO. A pressurized thick wall pipe is being tested in a 700℃ furnace to check the material degradation of an actual sized component.
Decolonization and Restorative Justice: Addressing Canada’s Indigenous Incarceration
Authors: Kito Ashu
Published: March 2024

Mass incarceration of Indigenous people has been well documented in Canadian prisons. It represents a national crisis resulting from the government's failure to eradicate the ongoing colonization problem and poses a threat to the sustainability of Indigenous people and their communities. The government's response includes the landmark Gladue decision, which essentially recognized mass incarceration as a crisis and required judges to consider the background of Indigenous offenders when sentencing, as well as the process of decolonizing the prison by introducing programs that teach Indigenous culture and history. However, both these responses have not effectively addressed the problem. In this paper, I argue that the Canadian government's response to the over-incarceration of Indigenous people represents a human rights issue that the Gladue Report has not alleviated because the report has not been implemented in a meaningful manner during bail hearing or sentencing. Therefore, the government should consider an alternative measure that returns to the traditional Indigenous law through the implementation of restorative justice, which has been proven to be effective.
Impulsive Buying in TikTok Live Streaming: Enhancing The Role of Telepresence, Brand Trust, and Flow State
Authors: Parahiyanti Cesya Rizkika , Dimara Noach Iriandi
Published: March 2024

Technology has taken a significant role in digital marketing. The presence of live streaming trades has formed a new trend for brands to increase their sales. Telepresence takes a significant role in forming brand trust and flow state which then can drive the audience to do impulsive buying. This research aims to examine the effect of variable telepresence, brand trust, and flow state to impulsive buying on Tiktokshop live streaming activities by EatSambel. The population in this research the users of Tiktok application who ever watched the live streaming of EatSambel with 228 samples which is chosen by purposive sampling technique and the data collecting used questionnaires. The research analysis used SEM-PLS which is managed by SmartPLS 3 software. The result of the data showed that telepresence has positively and significantly effect to impulsive buying, brand trust, and flow state. Flow state also has positively and significantly effect towards impulsive buying, while the effect of brand trust to impulsive buying is not significant. These findings provide a practical understanding of the quality of telepresence and interesting interactions in live streaming that can be considered by marketers to increase sales by encouraging impulsive buying behaviour in consumers.
SUN PROTECTION FACTOR (SPF) VALUE AND PHYSICAL PROPERTIES OF PURIFIED GAMBIER GEL PREPARATION
Authors: Faizin Muhammad Asrofi , Purwanto Purwanto
Published: March 2024

Gambier is an export product from Sumatera, Indonesia, that can be purified and utilized in cosmetic preparations. The content of phenolic and flavonoid compounds of purified gambier has a potential skin protection against UV rays. The chemical content of extract is closely related to the polarity of solvent, so this study aims to analyze the effect of ethanol concentration as solvent in gambier purification on phenolic content, flavonoids, and SPF value. The ethanol concentrations for this purpose were 0%, 25%, 50%, 75% and 96%. Total phenolic and flavonoid contents were analyzed by colorimetric method, whereas the SPF value of gel was measured by UV spectrophotometer. The gel preparation was evaluated for its physical properties including organoleptic test, spreadability, adhesiveness, viscosity, pH and stability. Statistical analysis performed with one-way ANOVA at 95% confidence level. As the results, ethanol concentration significantly influenced phenolic, flavonoid content and SPF values. The highest phenolic content was obtained in purification by 50% ethanol with a value of 757.2 ± 13.1 mg GAE/g, while highest flavonoid content was achieved in 96% ethanol at 5.18 ± 0.21 mg QE/g. Ethanol concentration with highest SPF value was 96% at 27.07 ± 0.33. In the gambier gel formulation with 0.2% dose had an SPF value of 6.60 ± 0.58. The gel has good homogeneity, viscosity, and pH for cosmetic preparations but poor spreadability. The stability of the gel formulation changed after accelerated stability testing for 4 weeks
In memory of Georgy Ivanovich Eroshkin
Authors:   The Central Astronomical Observatory of the RAS at Pulkovo, Pashkevich V.V.
Published: March 2024

In May of this year (May 22, 2024), the distinguished scientist, the candidate of physical and mathematical sciences (Ph.D.) Georgy Ivanovich Eroshkin would have turned 80 years old. Georgy Ivanovich was one of the leading experts in the field of classical and relativistic celestial mechanics. He was the leading researcher at the Central Pulkovo Astronomical Observatory of the Russian Academy of Sciences (GAO RAS), in 2000-2010 years he was the deputy director of the GAO RAS and head of the Department of Celestial Mechanics at the GAO RAS. He obtained a number of fundamental results in the field of mathematical modeling of the motion of large bodies of the Solar System and the construction of high-precision methods of numerical integration. Georgy Ivanovich’s scientific results have received international recognition. He died five years ago.
AĞIR TİCARİ ARAÇLARDA DİZEL YERİNE SIVILAŞTIRILMIŞ DOĞAL GAZ KULLANIMININ YAKIT TÜKETİMİNE ETKİSİ
Authors: Erçelik Bekir Barış , Doğan Bahadır
Published: March 2024

Bu çalışmada, ağır ticari araç sınıfında yer alan bir çekicinin performansı dizel ve sıvılaştırılmış doğal gaz (LNG) yakıtlı bir motora sahip olması durumunda deneysel olarak incelenmiştir. Testler sırasında her iki çekicide Euro VI normlarına sahip 338 kW gücünde motor kullanılmıştır. Araçlar toplam 41000 kg ağırlıkta eğimsiz düz bir yolda kullanılarak 85 km/h hızdan 20 km/h hıza serbest yavaşlama ve kalkıştan 85 km/h hıza ulaşana kadar hızlanma testlerine tabi tutulmuştur. Ayrıca 164,3 km’si otoyol, 44,4 km’si kırsal yol ve 54,7 km’si şehir içi yol olmak üzere toplam 263,4 km’den oluşan bir güzergâhta kullanılan araçların ortalama yakıt tüketim maliyetleri hesaplanmıştır. Sonuçlara göre, LNG yakıtlı aracın 100 km için yakıt maliyeti 1003,58 TL dizel aracın ise 1359,32 TL olarak hesaplanmıştır. LNG yakıtlı aracın ilk satış maliyetinin %30 daha pahalı olacağı öngörüldüğünde bile elde edilmiş olan %27 oranındaki yakıt tasarrufunun uzun yol kullanılan bir araç için kayda değer bir sonuç olduğu anlaşılmaktadır.
Finanzpolitische Zeitenwende oder Rolle rückwärts? Zum Urteil des Bundesverfassungsgerichts
Authors: Immerfall Stefan
Published: March 2024

Der Autor konstatiert in diesem Beitrag eine zu kritisierende generelle Neigung, politische Entscheidungen als Gebote des Rechts der politischen Auseinandersetzung zu entziehen. Die Auslagerung politischer Konflikte auf andere, namentlich das rechtliche Subsysteme sei (a) aus demokratischer Sicht begründungspflichtig, (b) führe regelmäßig zu schwerwiegenden Folgeproblemen und (c) stelle eine deutsche Sonderrolle dar, die im europäischen Staatenverbund kontraproduktiv wirkt.
A novel disulfidptosis-related prognostic gene signature and experimental validation identify ACTN4 as a novel therapeutic target in lung adenocarcinoma
Authors: Xie Kai , Wang Bin , Pang Pei , Li Guangbin , Yang Qianqian , Fang Chen , Jiang Wei , Feng Yu , Ma Haitao
Published: March 2024

BACKGROUND: Lung adenocarcinoma (LUAD) is a prevalent form of malignancy globally. Disulfidptosis is novel programmed cell death pathway based on disulfide proteins, may have a positive impact on the development of LUAD treatment strategies. OBJECTIVE: To investigate the impact of disulfidptosis-related genes (DRGs) on the prognosis of LUAD, developed a risk model to facilitate the diagnosis and prognostication of patients. We also explored ACTN4 (DRGs) as a new therapeutic biomarker for LUAD. METHODS: We investigated the expression patterns of DRGs in both LUAD and noncancerous tissues. To assess the prognostic value of the DRGs, we developed risk models through univariate Cox analysis and lasso regression. The expression and function of ACTN4 was evaluated by qRT-PCR, immunohistochemistry and in vitro experiments. The TIMER examined the association between ACTN4 expression and immune infiltration in LUAD. RESULTS: Ten differentially expressed DRGs were identified. And ACTN4 was identified as potential risk factors through univariate Cox regression analysis (P< 0.05). ACTN4 expression and riskscore were used to construct a risk model to predict overall survival in LUAD, and high-risk demonstrated a significantly higher mortality rate compared to the low-risk cohort. qRT-PCR and immunohistochemistry assays indicated ACTN4 was upregulated in LUAD, and the upregulation was associated with clinicopathologic features. In vitro experiments showed the knockdown of ACTN4 expression inhibited the proliferation in LUAD cells. The TIMER analysis demonstrated a correlation between the expression of ACTN4 and the infiltration of diverse immune cells. Elevated ACTN4 expression was associated with a reduction in memory B cell count. Additionally, the ACTN4 expression was associated with m6A modification genes. CONCLUSIONS: Our study introduced a prognostic model based on DRGs, which could forecast the prognosis of patients with LUAD. The biomarker ACTN4 exhibits promise for the diagnosis and management of LUAD, given its correlation with tumor immune infiltration and m6A modification.
Multi-omics comprehensive analysis reveals the predictive value of N6-methyladenosine- related genes in prognosis and immune escape of bladder cancer
Authors: Liu Yang , Pang Zhongqi , Wang Jianshe , Wang Jinfeng , Ji Bo , Xu Yidan , He Jiaxin , Zhang Lu , Han Yansong , Shen Linkun , Xu Wanhai , Ren Minghua
Published: March 2024

BACKGROUND:

N6-methyladenosine (m6A) is the most frequent RNA modification in mammals, and its role in bladder cancer (BC) remains rarely revealed.

OBJECTIVE:

To predict the value of m6A-related genes in prognosis and immunity in BC.

METHODS:

We performed multiple omics analysis of 618 TCGA and GEO patients and used principal component analysis (PCA) to calculate the m6A score for BC patients.

RESULTS:

We described the multiple omics status of 23 m6A methylation-related genes (MRGs), and four m6A clusters were identified, which showed significant differences in immune infiltration and biological pathways. Next, we intersected the differential genes among m6A clusters, and 11 survival-related genes were identified, which were used to calculate the m6A score for the patients. We found that the high-score (HS) group showed lower tumor mutation burden (TMB) and TP53 mutations and better prognosis than the low-score (LS) group. Lower immune infiltration, higher expression of PD-L1, PD-1, and CTLA4, and higher immune dysfunction and immune exclusion scores were identified in the LS group, suggesting a higher possibility of immune escape. Finally, the experimental verification shows that the m6A related genes, such as IGFBP1, plays an important role in the growth and metastasis of bladder cancer.

CONCLUSIONS:

These findings revealed the important roles of m6A MRGs in predicting prognosis, TMB status, TP53 mutation, immune functions and immunotherapeutic response in BC.
Computability and non-monotone induction
Authors: Normann Dag
Published: March 2024

Non-monotone inductive definitions were studied in the late 1960’s and early 1970’s with the aim of understanding connections between the complexity of the formulas defining the induction steps and the ordinals measuring the rank of the inductive process. In general, any type 2 functional will generate an inductive process, and in this paper we will view non-monotone induction as a functional of type 3. We investigate the associated computation theory of this functional inherited from the Kleene schemes and we investigate the associated companion of sets with codes computable in the functional of non-monotone induction. The interest in this functional is motivated from observing that constructions via non-monotone induction appear to be natural in classical analysis.

There are two groups of results: We establish strong closure properties of the least ordinal without a code computable in the functional of non-monotone induction, and we provide a characterisation of the class of functionals of type 3 computable from this functional, a characterisation in terms of sequential operators working in transfinite time. We will also see that the full computational power of non-monotone induction is required when this principle is used to construct functionals witnessing the compactness of the Cantor space and of closed, bounded intervals.
Differential diagnosis of erythemato-squamous diseases using a hybrid ensemble machine learning technique
Authors: Swain Debabrata , Mehta Utsav , Mehta Meet , Vekariya Jay , Swain Debabala , Gerogiannis Vassilis C. , Kanavos Andreas , Acharya Biswaranjan
Published: March 2024

Erythemato-squamous Diseases (ESD) encompass a group of common skin conditions, including psoriasis, seborrheic dermatitis, lichen planus, pityriasis rosea, chronic dermatitis, and pityriasis rubra pilaris. These dermatological conditions affect a significant portion of the population and present a current challenge for accurate diagnosis and classification. Traditional classification methods struggle due to shared characteristics among these diseases. Machine Learning offers a valuable tool for aiding clinical decision-making in ESD classification. In this study, we leverage the UC Irvine (UCI) dermatology dataset by applying necessary preprocessing steps to handle missing data. We conduct a comparative analysis of two feature selection methods: One-way ANOVA and Chi-square test. To enhance the model’s performance, we employ hyper-parameter tuning through GridSearchCV. The training process encompasses various algorithms, including Support Vector Machine (SVM), Logistic Regression, k-Nearest Neighbors (kNN), and Decision Trees. The culmination of our work is a hybrid ensemble machine learning model that combines the strengths of the trained classifiers. This ensemble classifier achieves an impressive accuracy of 98.9% when validated using a 10-fold cross-validation approach.
RETRACTED: A collaborative filtering method by fusion of facial information features
Authors: Wang Shuo , Yang Jing , Yang Yue
Published: March 2024

This article has been retracted. A retraction notice can be found at https://doi.org/10.3233/JIFS-219433.
A novel neutrosophic cubic MADM method based on Aczel-Alsina operator and MEREC and its application for supplier selection
Authors: Zhai Shanshan , Fan Jianping , Liu Lin
Published: March 2024

Neutrosophic cubic set (NCS) can process complex information by choosing both interval value and single value membership and indeterminacy and falsehood components. The aggregation operators based on Aczel-Alsina t-norm and t-corm are quite effective for evaluating the interrelationship among attributes. The purpose of this paper is to diagnose the interrelationship among attributes with neutrosophic cubic information, and propose a multi-attribute decision-making(MADM) method for supplier selection problem with unknown weight under neutrosophic cubic environment. We defined neutrosophic cubic Aczel-Alsina (NC-AA) operator and neutrosophic cubic Aczel–Alsina weighted arithmetic average (NCAAWAA) operator, then we discussed various important results and some properties of the proposed operators. Additionally, we proposed a MADM method under the presence of the NC-AAWAA operator. When the weights of attributes are unknown, we use the MEREC method to determine the weights. Later, the NC-AAWAA operator and MEREC method are applied to address the supplier selection problem. Finally, a sensitivity analysis and a comparative analysis are conducted to illustrate the stability and superiority of the proposed method. The results show the NC-AAWAA operator can handle the interrelationship among complex information more effectively, and MEREC method can weight the attributes based on the removal effect of a neutrosophic cubic attribute.
RETRACTED: Systematic review and meta-analysis of the screening and identification of key genes in gastric cancer using DNA microarray database
Authors: Duan Wenbiao , Yang Mingjin , Sun Weiliang , Xia Mingmin , Zhu Hui , Gu Chijiang , Zhang Haiqiang
Published: March 2024

This article has been retracted. A retraction notice can be found at https://doi.org/10.3233/JIFS-219433.
Automatic detection of obsessive-compulsive disorder from EEG signals based on Hilbert-Huang transform and sparse coding classification
Authors: Hong Yuntao
Published: March 2024

Obsessive-compulsive disorder (OCD) is a chronic disease and psychosocial disorder that significantly reduces the quality of life of patients and affects their personal and social relationships. Therefore, early diagnosis of this disorder is of particular importance and has attracted the attention of researchers. In this research, new statistical differential features are used, which are suitable for EEG signals and have little computational load. Hilbert-Huang transform was applied to EEGs recorded from 26 OCD patients and 30 healthy subjects to extract instant amplitude and phase. Then, modified mean, variance, median, kurtosis and skewness were calculated from amplitude and phase data. Next, the difference of these statistical features between various pairs of EEG channels was calculated. Finally, different scenarios of feature classification were examined using the sparse nonnegative least squares classifier. The results showed that the modified mean feature calculated from the amplitude and phase of the interhemispheric channel pairs produces a high accuracy of 95.37%. The frontal lobe of the brain also created the most distinction between the two groups among other brain lobes by producing 90.52% accuracy. In addition, the features extracted from the frontal-parietal network produced the best classification accuracy (93.42%) compared to the other brain networks examined. The method proposed in this paper dramatically improves the accuracy of EEG classification of OCD patients from healthy individuals and produces much better results compared to previous machine learning techniques.
Impact of missing data and ICC on full information maximum-likelihood estimation in multilevel SEMs
Authors: Niu Chunling
Published: March 2024

A Monte Carlo simulation study was conducted to investigate the performance of full information maximum-likelihood (FIML) estimator in multilevel structural equation modeling (SEM) with missing data and different intra-class correlations (ICCs) coefficients. The study simulated the influence of two independent variables (missing data patterns, and ICC coefficients) in multilevel SEM on five outcome measures (model rejection rates, parameter estimate bias, standard error bias, coverage, and power). Results indicated that FIML parameter estimates were generally robust for data missing on outcomes and/or higher-level predictor variables under the data completely at random (MCAR) and for data missing at random (MAR). However, FIML estimation yielded substantially lower parameter and standard error bias when data was not missing on higher-level variables, and in high rather than in low ICC conditions (0.50 vs 0.20). Future research should extend to further examination of the impacts of data distribution, complexity of the between-level model, and missingness on the between-level variables on FIML estimation performance.
Parametric test based on the bootstrapping approach for the MANOVA under a Behrens-Fisher problem
Authors: Singthongchai Jatsada , Thongmual Noppakun , Nitisuk Nirun
Published: March 2024

This article presents a comparison of multivariate normal mean vectors under covariance positive definite matrices. We introduce an improved parametric bootstrap (IPB) approach for addressing the multivariate Behrens-Fisher problem, specifically focusing on cases with unequal covariance matrices. Additionally, we evaluate the performance of the IPB test by comparing it with three existing tests: the parametric bootstrap (PB) test, the generalized variable (GV) test, and the Johansen test. Through Monte Carlo simulation, our results demonstrate that both the IPB test and the PB test exhibit superior control over Type I error rates compared to the GV and Johansen tests. Notably, the IPB test outperforms the PB test in terms of controlling Type I error rates. Consequently, our study concludes that the IPB test represents a preferred statistical method for testing the equality of mean vectors in the multivariate Behrens-Fisher problem.
Multiple conformity tests to assess deviations from the Newcomb-Benford Law (NBL): A replication of Koch and Okamura (2020)
Authors: Figueiredo Dalson , Silva Lucas
Published: March 2024

In this paper, we critically reevaluate Koch and Okamura’s (2020) conclusions on the conformity of Chinese COVID-19 data with Benford’s Law. Building on Figueiredo et al. (2022), we adopt a framework that combines multiple tests, including Chi-square, Kolmogorov-Smirnov, Euclidean Distance, Mean Absolute Deviation, Distortion Factor, and Mantissa Distribution. The primary rationale behind employing multiple tests is to enhance the robustness of our inference. The main finding of the study indicates that COVID-19 infections in China do not adhere to the distribution expected under Benford’s Law, nor does it align with the figures observed in the U.S. and Italy. The usefulness of deviations from Benford’s Law in detecting misreported or fraudulent data remains controversial. However, addressing this question requires a more careful statistical analysis than what is presented in the Koch and Okamura (2020) paper. By employing a combination of several tests using fully transparent procedures, we establish a more reliable approach to evaluating conformity to the Newcomb-Benford Law in applied research.