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Artykuły w czasopismach na temat "SUMO SITES PREDICTION"
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Zhao, Qi, Yubin Xie, Yueyuan Zheng, Shuai Jiang, Wenzhong Liu, Weiping Mu, Zexian Liu, Yong Zhao, Yu Xue i Jian Ren. "GPS-SUMO: a tool for the prediction of sumoylation sites and SUMO-interaction motifs". Nucleic Acids Research 42, W1 (31.05.2014): W325—W330. http://dx.doi.org/10.1093/nar/gku383.
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Ijaz, Amna. "SUMOhunt: Combining Spatial Staging between Lysine and SUMO with Random Forests to Predict SUMOylation". ISRN Bioinformatics 2013 (17.06.2013): 1–11. http://dx.doi.org/10.1155/2013/671269.
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Modification with SUMO protein has many key roles in eukaryotic systems which renders the identification of its target proteins and sites of considerable importance. Information regarding the SUMOylation of a protein may tell us about its subcellular localization, function, and spatial orientation. This modification occurs at particular and not all lysine residues in a given protein. In competition with biochemical means of modified-site recognition, computational methods are strong contenders in the prediction of SUMOylation-undergoing sites on proteins. In this research, physicochemical properties of amino acids retrieved from AAIndex, especially those involved in docking of modifier and target proteins and optimal presentation of target lysine, in combination with sequence information and random forest-based classifier presented in WEKA have been used to develop a prediction model, SUMOhunt, with statistics significantly better than all previous predictors. In this model 97.56% accuracy, 100% sensitivity, 94% specificity, and 0.95 MCC have been achieved which shows that proposed amino acid properties have a significant role in SUMO attachment. SUMOhunt will hence bring great reliability and efficiency in SUMOylation prediction.
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Lee, Choong-Eun, Tam Tran, Seol-Hee Kim, Ki-Sa Sung i Cheol-Yong Choi. "Regulation of IL-4-induced STAT6 activation by SUMOylation (P6307)". Journal of Immunology 190, nr 1_Supplement (1.05.2013): 184.15. http://dx.doi.org/10.4049/jimmunol.190.supp.184.15.
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Abstract As a key signaling molecule in the cytokine-mediated transcriptional activation STATs are shown to undergo PTMs including phosphorylation, acetylation, methylation, ubiquitination and SUMOylation. The SUMO-modification of STAT1 has been implicated in the regulation of protein stability, nuclear translocation, and transcriptional activation, probably through the reduction of the formation and life-span of the active dimer. As a part of regulation of IL-4 signaling mechanism, we have investigated the role of SUMOylation on STAT6 activation. We have identified potential SUMOylation sites on STAT6 by SUMOplot prediction program analysis and observed the IL-4-induced SUMOlyation of STAT6 in HeLa cells. The introduction of mutation at a potential SUMO site K636 and transfection of shRNA of SUMO-conjugating enzyme UBC9 resulted in the inhibition of tyrosine phosphorylation at Y641 induced by IL-4. The results indicate that endogenous SUMOylation reaction of STAT6 is critical for IL-4-induced STAT6 phosphorylation. Conversely, the forced expression of SUMO-1 and STAT6 caused cytosolic relocalization of both STAT6 and phospho-STAT6 induced by IL-4 as demonstrated by Western blot and confocal analysis. Our data suggest that SUMO-modification of STAT6 may play dual roles in the regulation of phosphorylation and nuclear translocation of STAT6 during IL-4 signal transduction.
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Yu, Jian, Jianping Lan, Yuanyuan Zhu, Xiaoyu Lai i He Huang. "Sumoylation of TRF1 Is Essential for Its Recruitment to ALT-Associated PML Bodies." Blood 110, nr 11 (16.11.2007): 4169. http://dx.doi.org/10.1182/blood.v110.11.4169.4169.
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Abstract To achieve unlimited proliferative potential, most cancer cells activate telomerase to maintain telomeres. However, some cancer cells elongate telomeres through a telomerase-independent pathway termed alternative lengthening of telomeres (ALT). These ALT cells contain a novel promyelocytic leukemia (PML) body (ALT-associated PML body, APB), which comprises telomeric DNA and a number of proteins, including PML protein, the telomere binding proteins TRF1 and TRF2, replication factor A, and recombination factors Rad51, Rad52, and the Rad50/Mre11/NBS1 complex. TRF1, as the first identified telomeric binding protein, binds the duplex telomeric repeats at telomere ends. It plays an important role in telomere length control, telomeric ends shelter and cell cycle regulation. In ALT cell lines, TRF1 co-localized with PML protein at APBs, but the exact mechanism of its recruitment to APBs is not clear. Here we show that TRF1 localizes to PML bodies in about 5% of an asynchronously growing culture of U2OS cells and the percentage of cells with colocalization of TRF1 and PML bodies increases to about 40% in cells enriched in G2/M, which is consistent with the previous studies. Furthermore, our results show that TRF1 is modified by the small ubiquitin-like protein SUMO-1 in vivo and in vitro. Firstly, 293T cells were transfected with Flag-TRF1, HA-Ubc9, GFP-SUMO1 and then immunoprecipitated by using FLAG-M2 gel under denaturing conditions. Immunoblotting with GFP and Flag antibodies demonstrated that TRF1 is modified by SUMO-1 in vivo. Next, in vitro SUMO-1 conjugation assay of TRF1 was employed. The results showed that TRF1 is conjugated with SUMO-1 in the presence of purified recombinant protein SAE1/SAE2, Ubc9, SUMO1, His-TRF1 and ATP. Either SAE1/SAE2, Ubc9, SUMO-1 or ATP was omitted from the reaction abolished the sumoylation of TRF1. Previous studies have shown that sumoylation controls the recruitment of several proteins to PML bodies, so we examined whether sumoylation of TRF1 is required for its recruitment to APBs. We mutated the potential sumoylation sites of TRF1 according to the computational prediction and then transfected it into U2OS cells to examine its localization. The results showed that TRF1 mutant does not localize to PML bodies. Taken together, all these results suggest that TRF is modified by SUMO-1 and sumoylation of TRF1 is essential for its recruitment to APBs in ALT cells.
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Qian, Ying, Shasha Ye, Yu Zhang i Jiongmin Zhang. "SUMO-Forest: A Cascade Forest based method for the prediction of SUMOylation sites on imbalanced data". Gene 741 (maj 2020): 144536. http://dx.doi.org/10.1016/j.gene.2020.144536.
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Liu, Yan, Zhenhua Zheng, Bo Shu, Jin Meng, Yuan Zhang, Caishang Zheng, Xianliang Ke, Peng Gong, Qinxue Hu i Hanzhong Wang. "SUMO Modification Stabilizes Enterovirus 71 Polymerase 3D To Facilitate Viral Replication". Journal of Virology 90, nr 23 (14.09.2016): 10472–85. http://dx.doi.org/10.1128/jvi.01756-16.
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ABSTRACT Accumulating evidence suggests that viruses hijack cellular proteins to circumvent the host immune system. Ubiquitination and SUMOylation are extensively studied posttranslational modifications (PTMs) that play critical roles in diverse biological processes. Cross talk between ubiquitination and SUMOylation of both host and viral proteins has been reported to result in distinct functional consequences. Enterovirus 71 (EV71), an RNA virus belonging to the family Picornaviridae , is a common cause of hand, foot, and mouth disease. Little is known concerning how host PTM systems interact with enteroviruses. Here, we demonstrate that the 3D protein, an RNA-dependent RNA polymerase (RdRp) of EV71, is modified by small ubiquitin-like modifier 1 (SUMO-1) both during infection and in vitro . Residues K159 and L150/D151/L152 were responsible for 3D SUMOylation as determined by bioinformatics prediction combined with site-directed mutagenesis. Also, primer-dependent polymerase assays indicated that mutation of SUMOylation sites impaired 3D polymerase activity and virus replication. Moreover, 3D is ubiquitinated in a SUMO-dependent manner, and SUMOylation is crucial for 3D stability, which may be due to the interplay between the two PTMs. Importantly, increasing the level of SUMO-1 in EV71-infected cells augmented the SUMOylation and ubiquitination levels of 3D, leading to enhanced replication of EV71. These results together suggested that SUMO and ubiquitin cooperatively regulated EV71 infection, either by SUMO-ubiquitin hybrid chains or by ubiquitin conjugating to the exposed lysine residue through SUMOylation. Our study provides new insight into how a virus utilizes cellular pathways to facilitate its replication. IMPORTANCE Infection with enterovirus 71 (EV71) often causes neurological diseases in children, and EV71 is responsible for the majority of fatalities. Based on a better understanding of interplay between virus and host cell, antiviral drugs against enteroviruses may be developed. As a dynamic cellular process of posttranslational modification, SUMOylation regulates global cellular protein localization, interaction, stability, and enzymatic activity. However, little is known concerning how SUMOylation directly influences virus replication by targeting viral polymerase. Here, we found that EV71 polymerase 3D was SUMOylated during EV71 infection and in vitro . Moreover, the SUMOylation sites were determined, and in vitro polymerase assays indicated that mutations at SUMOylation sites could impair polymerase synthesis. Importantly, 3D is ubiquitinated in a SUMOylation-dependent manner that enhances the stability of the viral polymerase. Our findings indicate that the two modifications likely cooperatively enhance virus replication. Our study may offer a new therapeutic strategy against virus replication.
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Liu, Boshu, Sujun Li, Yinglin Wang, Lin Lu, Yixue Li i Yudong Cai. "Predicting the protein SUMO modification sites based on Properties Sequential Forward Selection (PSFS)". Biochemical and Biophysical Research Communications 358, nr 1 (czerwiec 2007): 136–39. http://dx.doi.org/10.1016/j.bbrc.2007.04.097.
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Ho, Nhat‐Minh, i Jeung‐Hwan Doh. "Prediction of ultimate strength of concrete walls restrained on three sides". Structural Concrete 20, nr 3 (28.03.2019): 942–54. http://dx.doi.org/10.1002/suco.201800188.
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Kawai, Toru, Mohammad Kholid Ridwan i Manabu Kanda. "Evaluation of the Simple Urban Energy Balance Model Using Selected Data from 1-yr Flux Observations at Two Cities". Journal of Applied Meteorology and Climatology 48, nr 4 (1.04.2009): 693–715. http://dx.doi.org/10.1175/2008jamc1891.1.
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Abstract The authors’ objective was to apply the Simple Urban Energy Balance Model for Mesoscale Simulation (SUMM) to cities. Data were selected from 1-yr flux observations conducted at three sites in two cities: one site in Kugahara, Japan (Ku), and two sites in Basel, Switzerland (U1 and U2). A simple vegetation scheme was implemented in SUMM to apply the model to vegetated cities, and the surface energy balance and radiative temperature TR were evaluated. SUMM generally reproduced seasonal and diurnal trends of surface energy balance and TR at Ku and U2, whereas relatively large errors were obtained for the daytime results of sensible heat flux QH and heat storage ΔQS at U1. Overall, daytime underestimations of QH and overestimations of ΔQS and TR were common. These errors were partly induced by the poor parameterization of the natural logarithm of the ratio of roughness length for momentum to heat (κB−1); that is, the observed κB−1 values at vegetated cities were smaller than the simulated values. The authors proposed a new equation for predicting this coefficient. This equation accounts for the existence of vegetation and improves the common errors described above. With the modified formula for κB−1, simulated net all-wave radiation and TR agreed well with observed values, regardless of site and season. However, at U1, simulated QH and ΔQS were still overestimated and underestimated, respectively, relative to observed values.
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Hipólito-Romero, Enrique, Eliezer Cocoletzi-Vásquez, José M. Ramos-Prado, Cesar Espinoza, Magdiel Torres-de la Cruz i Jorge Ricaño-Rodríguez. "Breve aproximación a la naturaleza genómica de Moniliophthora roreri CPMRT01 aislado de cacao en Tabasco, México//Brief approach to the genomic nature of Moniliophthora roreri CPMRT01 isolated from cocoa in Tabasco, Mexico". Biotecnia 22, nr 2 (21.03.2020): 39–49. http://dx.doi.org/10.18633/biotecnia.v22i2.1244.
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Moniliophthora roreri es un hongo de suma importancia agroeconómica principalmente en el continente americano, ya que es el agente causal de la moniliasis de al menos cuatro especies de cacao. El genoma de este hongo consta de aproximadamente 52,3 Mpb, cuyos genes de interés se reagrupan dependiendo de su naturaleza (e.g. hemibiotróficos, biotróficos y fitopatogénicos). Por otro lado, Moniliophthora es capaz de metabolizar proteínas involucradas en procesos de infección, regulación metabólica y mecanismos de defensa. El objetivo principal de este trabajo fue caracterizar un fragmento del genoma de una cepa de M. roreri, previamente aislada de cacao en el Estado de Tabasco, México. Para ello, se implementó una estrategia experimental que involucró la generación de bibliotecas genómicas así como una secuenciación de regiones nucleotídicas consenso, predicción heurística-funcional e identificación de hipotéticos dominios conservados, respectivamente. El estudio permitió explorar alrededor del 16 % del genoma de la cepa. Entre los resultados y conclusiones obtenidas más interesantes, se generaron reconstrucciones filogenéticas de máxima identidad respecto a un genoma de referencia y, cuyos transcritos se encontrarían involucrados en procesos de fitopatogenicidad y metabolismo secundario, identificándose aparentes dominios proteicos y sitios catalíticos activos en algunos de los cóntigos estudiados.ABSTRACTMoniliophthora roreri is a fungus of extreme agroeconomic importance mainly in the American continent, since it is the causal agent of moniliasis of at least four cocoa species. The genome of this fungus consists of approximately 52,3 Mbp, whose genes of interest may be regrouped depending on their nature (e.g. hemibiotrophics, biotrophics and phytopathogenics). On the other hand, Moniliophthora is liable to metabolize proteins involved in infection processes, metabolic regulation and defense mechanisms. The aim of this work was to partially characterize a fragment of the genome of a M. roreri strain previously isolated from cocoa in the State of Tabasco, Mexico. To reach this goal, an experimental strategy was implemented that involved the generation of genomic libraries as well as a consensus nucleotide region sequencing, functional-heuristic prediction and identification of hypothetical conserved domains, respectively. The study allowed to explore about 16 % of the strain´s genome. Among the most interesting results and conclusions obtained, phylogenetic reconstructions of maximum identity respect to the reference genome were reached, whose transcripts would be involved in phytopathogenic processes and secondary metabolism, identifying apparent protein domains and active catalytic sites in some of the contigs under study.
Rozprawy doktorskie na temat "SUMO SITES PREDICTION"
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TOMAR, RAVI KUMAR. "STUDY OF SMALL UBIQUITININ LOKE MODIFIERS AND CHAPERONIC SIGNALING IN NON-INSULIN DEPENDENT DIABETES MELLITUS". Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14955.
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Small ubiquitin-related modifier (SUMO) family proteins function inpost-translational modifications of proteinsby covalently attaching to them. This helps in modification of many proteins involve in diverse cellular processes, like nuclear transport, transcriptional regulation, signal transduction andmaintenance of genome integrity. An enzyme pathway which is related to the ubiquitin pathway control theattachment between SUMO and proteins.
Heat shock protein 27 (HSP27) helps stressed cells to survive in adverse conditions by accumulating in them. HSP27 function in the ubiquitination process is already known. Here, we showed that HSP27 is also involved in protein sumoylation, in the case of diabetes. It was found that HSP27 helps in increasing the number of cell proteins modified by small ubiquitin-like modifier (SUMO)-2/3. In stressed cells, HSP27 form large oligomer which binds to HSF1 and enters the nucleus which induces SUMO-2/3modification. Hence by this study we can say that HSP27 can be use as SUMO-E3 ligase specific for SUMO 2/3.
Virtual screening of ligands and then docking against SUMO protein was performed using PatchDock and Swissdocksoftwares. ZINC53683754 [(2S)-8-{(tert-butoxycarbonyl) amino}-2-(1H-indole-3-oyl)octanoic acid] andZINC53683750 [(2S)-2-(1H-indole-3-yl)hexanoic acid] comes out to be good SUMO protein binders.
This study proves that sumoylation has a role in the regulation of proteins involved in glucose metabolism. It identifies a new mechanism for the study of functions of SUMO proteins at the post-translational level and helps in identification of potential SUMO binding targets and potential ligand binders.
It was found that drug docking significantly reduces the number of experiments and thereby cut cost while examining the utility of any chemical as a drug before going through any in vivo or in vitro analysis.
Streszczenia konferencji na temat "SUMO SITES PREDICTION"
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Wang, Bo, Banglin Liu, Yong-Yi Wang, Alex Wang i Steve Rapp. "Burst Pressure Prediction of Pipes With SCC Colonies: Development of Intelligent Flaw Interaction Rules". W 2020 13th International Pipeline Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipc2020-9693.
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Abstract Stress Corrosion Cracking (SCC) often occurs in clusters or colonies containing anywhere from a few cracks to hundreds of individual cracks. Multiple closely spaced cracks may interact, resulting in a burst pressure lower than what might be expected from a single crack. Most existing flaw interaction rules account for these interactions by using a single interacting crack to represent multiple cracks when the separations between them are less than a critical spacing. The length of this interacting crack is usually the sum of the individual crack length plus the spacing between them. Using this interacting length and the maximum depth in the colony could produce overly conservative burst pressure predictions which can lead to unnecessary hydrotests and/or other remediation actions. This two-paper series covers the PRCI-funded work aimed at the development of intelligent flaw interaction rules (termed PRCI-CRES SIA-1-5 rules) that can account more accurately the impact of multiple cracks without being overly conservative. This paper focuses on the development of the rules using numerical analyses. A companion paper covers the evaluation of the rules through full-scale burst tests. The PRCI-CRES SIA-1-5 rules use the principles of equivalent impact among multiple interacting cracks and represent the magnitude of the impact by a single virtual crack. The new rules do not rely on a critical spacing to determine whether there is an interaction. The magnitude of the interaction is a continuous function of the size of adjacent cracks and the spacing between them. A large number of finite element analyses (FEA) were conducted to examine the interaction among cracks for many crack configurations, including coplanar and noncoplanar cracks with different sizes and spacings. An analysis process was then developed to use the sizes and spacings of all cracks in an SCC colony to predict the equivalent virtual crack size and burst pressure.
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Ma, L., A. S. Kobayashi, S. N. Atluri i P. W. Tan. "Crack Linkup at Multiple Site Damage". W ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0354.
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Abstract A commonly used design criterion for predicting the onset of crack link up at a multiple site damage (MSD) is when the sum of the plastic zones of two adjacent cracks is equal to the remaining ligament (Swift 1985, Broek et al 1994). The collapse load predicted by this criterion, however, will differ with the analytical plastic zone and in general, will yield a nonconservative load. Recently, Pyo et al (1997) have shown that the T* integral, which was designed for elastic-plastic fracture mechanics, can predict the extent of stable crack growth and the subsequent collapse load of wide-panel MSD experiments (deWit et al, 1994). The purpose of this paper is to present experimental/numerical results on stable crack growth and linkup of idealized MSD based on the T* integral. Moiré interferometry was used to determine the orthogonal displacement fields surrounding stably growing cracks in 0.8 mm thick 2024-T3 aluminum specimens with two or three cracks. Fatigue precracked cracks extended toward each other from two circular holes, which were 25.4 mm apart to simulate fastener holes in airplane fuselage, close to the outside edges of the specimens. A longer center crack from a center hole in the wider, three-crack specimens with three holes spaced 25.4 mm apart, provided information on the lead crack effect. T*ε integral, where ε is the distance of an elongating integration contour from the stably growing crack, was evaluated from the Moiré data using the procedure established by Okada et al (1996). ε in all studies was equated to the specimen thickness. An elastic-plastic finite element (FE) model of the fracture specimens were executed in its generation mode (Kobayashi, 1979) by inputting the measured Moiré displacement data along the width, 20 mm away from the crackline, of the specimen. T*ε integral was evaluated using an equivalent domain integral (Nikishkov et al, 1987). The experimentally and the FE determined T*ε’s were in excellent agreement with each other. Moreover, the T*ε variation with stable crack growth closely followed the stable crack growth results generated previously using standard fracture specimens (Omori et al, 1998). Thus stable crack growth data generated by standard fracture specimens can be used to predict crack growth of MSD cracks. Collapsed load was reached when the remaining ligament exceeded the tensile strength of the 2024-T3 sheet and the two cracks rapidly propagated toward each other in the two-crack specimens. For the three-crack specimen, the lead crack propagated toward the smaller two MSD cracks.
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Matoušek, Václav, Robert Visintainer, John Furlan i Anders Sellgren. "Frictional Head Loss of Various Bimodal Settling Slurry Flows in Pipe". W ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5395.
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Abstract Pipe flows of bimodal settling slurries exhibit frictional head losses quite different from those determined simply as a sum of loss contributions by the individual fractions. Mechanisms governing flow friction and resulting from an interaction of grains of different fractions in transported slurry are not well understood. This makes a prediction of the frictional head loss in flows of bimodal slurries with Newtonian carrier uncertain. An extensive experimental campaign was conducted in GIW Hydraulic Laboratory in 2016 with slurries of four narrow graded fractions of the virtually same grain densities and very different grain sizes (carrier-liquid fraction, pseudo-homogeneous-, heterogeneous-, and stratified fractions). Besides testing of the individual fractions, different combinations of the fraction mixtures (bimodal, three- and four-component) were tested as well. In our previous work published in 2018, we employed experimental results for bimodal slurry composed of coarse granite rock (the stratified fraction) and fine sand (the pseudo-homogeneous fraction) to analyze the observed considerable reduction of the frictional head loss caused by an addition of the fine sand to the granite rock slurry. In this work, we extend our analysis to the other bimodal slurries composed of permutations of the four fractions (in total 3 additional bimodal slurries) with a major objective to identify possible mechanisms leading to a modification of the frictional head loss due to an addition of a finer fraction to a coarser mono-disperse slurry, and to quantify this effect for the purposes of a predictive four-component model (4CM). The investigation shows that the frictional loss of bimodal slurry is always smaller than the theoretical loss obtained as the sum of losses of the fractions, although the massive reduction observed in the slurry composed of the stratified rock and fine sand is not observed in any other bimodal slurry. The investigation also suggests that the friction effect obtained by the finer fraction addition is due to different mechanisms for different bimodal slurries although all mechanisms are associated with altering mechanical friction due to granular contacts. It is shown that the observed effects can be well reproduced by the friction loss model 4CM, calibrated by the experimental data set from the 203-mm pipe and validated by the data set from the 103-mm pipe.
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Acton, M. R., P. J. Baldwin, R. P. Cleaver i D. J. McCollum. "Methods for Assessing Risks at Above Ground Installations". W 2004 International Pipeline Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ipc2004-0573.
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This paper describes a package of computer models that has been developed to assess the risks from gas releases at above ground installations associated with natural gas transmission pipelines. The package can be applied to compressor stations (containing compressor enclosures and associated gas treatment equipment) and pressure reduction stations, through to single block valve installations. It has been designed for used by safety engineers in performing quantified risk and hazard analysis, as required to meet regulatory requirements, such as the COMAH Regulations or the DSEAR Regulations in the UK. It can also be used in the design stage of projects to support decisions related to site layout for example. The package contains a range of mathematical models to assess the consequences of accidental releases of gas (including outflow, dispersion, gas accumulation, fire, explosion and thermal and overpressure response), validated by data from large and full scale experiments. The individual models are linked in a logical manner constructed around a series of “knowledge bases” that provide a defined structure to allow a wide range of different scenarios to be assessed. The predictions of the consequences arising from various scenarios can be combined with estimates of the frequency of initiating events (based on industry statistics where available, or using predictive models), in risk calculation routines which sum the outcomes for the different scenarios to calculate individual and/or societal risk. To illustrate the use of the techniques, examples of their application are given. In particular, it is shown how the risks arising from releases from high pressure vessels or in confined volumes, such as compressor enclosures, can be evaluated.
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Niccolini Marmont Du Haut Champ, Carlo Alberto, Mario Luigi Ferrari, Paolo Silvestri i Aristide Fausto Massardo. "Signal Processing Techniques to Detect Centrifugal Compressors Instabilities in Large Volume Power Plants". W ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14795.
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Abstract The present paper shows signal processing techniques applied to experimental data obtained from a T100 microturbine connected with different volume sizes. This experimental activity was conducted by means of the test rig developed at the University of Genoa for hybrid systems emulation. However, these results can be extended to all advanced cycles in which a microturbine is connected with additional external components which lead to an increase of the plant volume size. Since in this case a 100 kW microturbine was used, the volume was located between the heat recovery unit outlet and the combustor inlet like in the typical cases related to small size plants. A modular vessel was used to perform and to compare the tests with different volume sizes. The main results reported in this paper are related to rotating stall and surge operations. This analysis was carried out to extend the knowledge about these risk conditions: the systems equipped with large volume size connected to the machine present critical issues related to surge and stall prevention, especially during transient operations towards low mass flow rate working conditions. Investigations conducted on acoustic and vibrational measurements can provide interesting diagnostic and predictive solutions by means of suitable instability quantifiers which are extracted from microphone and accelerometer data signals. Hence different possible tools for rotating stall and incipient surge identification were developed through the use of different signal processing techniques, such as Wavelet analysis and Higher Order Statistics Analysis (HOSA) methods. Indeed, these advanced techniques are necessary to maximize all the information conveyed by acquired signals, particularly in those environments in which measured physical quantities are hidden by strong noise, including both broadband background one (i.e. typical random noise) but also uninteresting components associated to the signal of interest. For instance, in complex coupled physical systems like the one it is meant to be studied, which do not satisfy the hypothesis of linear and Gaussian processes inside them, it is reasonable to exploit these kinds of tools, instead of the classical Fast Fourier Transform (FFT) technique by itself, which is mainly adapt for linear systems periodic analysis. The proposed techniques led to the definition of a quantitative indicator, the sum of all auto-bispectrum components modulus in the subsynchronous range, which was proven to be reliable in predicting unstable operation. This can be used as an input for diagnostic systems for early surge detection. Furthermore, the presented methods will allow the definition of some new features complementary with the ones obtainable from conventional techniques, in order to improve control systems reliability and to avoid false positives.
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Hsu, L. L. "Total Corrosion Control for Industrial Gas Turbines: Airborne Contaminants and Their Impact on Air/Fuel/Water Management". W ASME 1988 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1988. http://dx.doi.org/10.1115/88-gt-65.
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Turbine longevity in the field is determined by the extent of its operation within design limits under mechanical and thermal loads as well as the environmental effects that undermine material properties on component surfaces. It is standard practice for the original equipment manufacturer (OEM) to specify maximum concentrations of harmful contaminants in the fuel for corrosion control. Some manufacturers have deployed on-line, in-service monitoring systems designed to incorporate data, such as temperature, speeds and start-stop cycles, into a functional, quasi-empirical equation, with an environmental factor, to continuously assess the condition of the turbine package for maintenance and overhaul purposes. This environmental factor simply categorizes fuel types in some generic correlation of fuel with hot section degradation. This paper discusses the concept of air, fuel and water management, an approach that has evolved at the author’s Company as a focused and cost-effective means of assessing the total turbomachinery environment. The ultimate objective is to employ the methodology described above for hot section corrosion life prediction and optimized maintenance planning with minimal capitalization and operating costs for maximum economic payback. The fundamental principle of this approach is represented schematically in Fig. 1 and discussed in more detail in Ref. 1. For total corrosion control, the engine environment is the sum of all contaminants present in the air, fuel and water (or steam). Tradeoffs in fluid quality can be tolerated provided the combined total concentration of a critical contaminant does not exceed the maximum allowable limits. Instead of separate restrictions on air, fuel and water quality, combined limits on total concentrations should be defined which then allows each fluid to vary in quality, thus providing greater flexibility for accommodating customer requirements or site specific conditions.
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Agranat, Vladimir M., Sergei V. Zhubrin i Igor Pioro. "Multi-Group Two-Phase Flow Model of Drift Drop Plume". W 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30010.
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A homogeneous two-phase multi-group model of drift drop plumes emerging from natural draft cooling towers has been developed and validated using the experimental data obtained in the 1977 Chalk Point Dye Tracer Experiment (CPDTE). The conservation equations for mass fractions of water droplets having different sizes are solved in addition to the standard conservation equations for mixture mass, momentum, energy, water vapor mass fraction and turbulent quantities (turbulent kinetic energy and its dissipation rate). Extra terms are provided to the conservation equations for mass fractions of liquid water to account for the drift of water drops due to their gravitational settling. Various formulations for drift velocity and terminal velocity have been tested and compared. The phase change effects (condensation, evaporation, solidification and melting) are assumed to be negligible due to specific conditions of the experiment. The droplet-size distribution available at the cooling tower exit and containing the 25 groups of drops is simplified to 11 groups. Also, the 3-group and 1-group options are considered for comparison. The individual drop deposition fluxes and the total deposition flux are calculated and compared with the experimental data available at the sensors located on the 35° arcs at 500 and 1000 m from the cooling tower centerline. The total deposition flux is calculated as a sum of products of individual group mass concentrations of water drops and corresponding terminal velocities. The model has been incorporated into the commercial general-purpose Computational Fluid Dynamics (CFD) code, PHOENICS. The study has demonstrated a good agreement between the CFD predictions and the experimental data on the water vapor plume rise and the total drift deposition fluxes. In particular, the plume rise predictions agree well with experimental values (the errors are from 4% to 34% at different distances from the tower centerline). The predicted deposition fluxes are in agreement with the experimental values within a factor of 1.5, which is well within the industry acceptable error limits (a factor of 3). The model developed is recommended for analyzing the drift drop plumes under the conditions similar to CPDTE conditions of small Stokes numbers. It is easier to use and not less accurate than the multiphase Eulerian-Lagrangian CFD models used recently by various researchers for modeling CPDTE plume. The model has a potential to supplant or complement the latter in the computational analyses of gravitational phenomena in complex two-phase flows in engineering equipment and its environment.
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Gill, Peter, Peter Brown, David Tice, Norman Platts i Chris Currie. "Fatigue Initiation of 304L Stainless Steel Subject to Thermal Shock Loading in a PWR Environment". W ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93923.
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Abstract The evaluation procedures for fatigue initiation of nuclear class 1 components are defined in ASME BPVC Section III NB-3200 (Design by Analysis) and NB-3600 (Piping Design). Design fatigue curves are provided to establish the suitability of a component for cyclic service and define the allowable number of cycles as a function of applied stress amplitude (S-N curves). The number of load cycles at a particular strain range is then divided by the cycles to failure to obtain a partial usage factor., and the cumulative usage factor (CUF) for the component site, calculated from the sum of the partial usage factors, must be less than one. The original fatigue evaluation procedures did not include the effects of the PWR or BWR coolant environments, but laboratory test data indicate that significant fatigue life reductions can occur under such conditions, depending on strain rates and temperatures. These observations led to the formulation of modified procedures, originally published in NUREG-CR/6909 which required the usage factors to be increased by an additional environmental factor, Fen, which accounts for the deleterious effects of high temperature water. An ASME Code Case N-792-1 has now been included in ASME Section III which is based on the NUREG-CR/6909 equations, with some minor modifications. The Fen factors are derived from testing of membrane-loaded solid round tensile or tubular specimens at different strain rates and temperatures. The data were obtained using simple triangular waveforms, i.e. at constant strain rate, and the temperature was also constant for each test. However, for components subject to plant loading, the situation is significantly more complicated, with most major transients being thermal in origin. For a thermal shock transient some key characteristics become apparent. These are (i) temperature is out-of-phase with strain (ii) strain rate and temperature vary through the cycle with a faster strain rate at the top of the cycle (iii) stress decays through the wall of the component. Several assumptions need to be made in order to simplify the assessment of these sorts of transients. Examples of such assumptions include the choice of temperature for the calculation (e.g. maximum or average through the transient) and the method of strain rate calculation (e.g. assumption of constant strain rate, or integration through the cycle, i.e. the modified strain rate approach). These assumptions can be overly conservative and hence very restrictive for plant operators when making safety justifications. Improved models have been developed which weight fatigue damage through the cycle, which is consistent with recent observations from testing under complex load cycles. Although these models can more accurately predict fatigue life for loading that is representative of PWR transients, they still assume membrane loading which is unrealistic for thermal shock transients in thin walled components. Details of a testing capability at Wood (formerly Amec Foster Wheeler) or thermal shock testing in a PWR environment were presented in a previous paper (ASME PVP2018-84923). The predictions of fatigue initiation indicated test durations of 2–3 months based on the latest fatigue models for austenitic stainless steel. The current paper presents the results of the first thermal shock tests carried out on a type 304L stainless steel. The predictions are compared with experimental observations and the accuracy of the models are assessed.