82 results on '"CCV"'
Search Results
2. Diversity in clinical isolates of Ictalurid herpesvirus 1 (IcHV1) from U.S. farm‐raised catfish and virulence assessment in channel and channel × blue catfish hybrids.
- Author
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Venugopalan, Arun, White, Danielle, López‐Porras, Adrián, Ford, Lorelei, Ware, Cynthia, Lewis, Marsha A., Steadman, James M., Khoo, Lester H., Richardson, Bradley, Walker, Charles M., Byars, Todd S., Wise, David J., Griffin, Matt J., and Hanson, Larry A.
- Subjects
- *
RESTRICTION fragment length polymorphisms , *CHANNEL catfish , *EPITOPES , *BLOOD serum analysis , *GENETIC variation , *MONOCLONAL antibodies - Abstract
Ictalurid herpesvirus 1 (IcHV1) is the most significant viral agent in U.S. catfish aquaculture. Little is known regarding the genetic stability and antigenic variability of IcHV1. Herein, the genetic and antigenic diversity of IcHV1 field isolates was assessed by restriction fragment length polymorphism (RFLP) analysis and serum neutralization assays. RFLP analysis identified two distinct genotypes (IcHV1A and IcHV1B), both discrete from blue catfish alloherpesvirus (BCAHV). Neutralization assays with anti‐IcHV1 monoclonal antibody Mab‐95 indicate shared antigenic determinants for IcHV1A and IcHV1B that are absent from BCAHV, which Mab‐95 did not neutralize. Virulence assessments with representative isolates demonstrate significant differences between isolates within RFLP groups and pooled RFLP group data suggest IcHV1B (pooled survival [mean ± SE]: 58.3% ± 2.6) may be more virulent than IcHV1A (survival: 68.6% ± 2.4). Rechallenges with representative IcHV1A and IcHV1B isolates indicate a cross‐protective effect, with fish surviving initial exposure to IcHV1A or IcHV1B showing robust protection when subsequently re‐exposed to IcHV1A or IcHV1B. This work demonstrated significant differences in virulence between case isolates, identifying two discrete IcHV1 lineages, distinct from BCAHV, with similar virulence in channel and channel × blue catfish hybrids and a cross‐protective effect in catfish surviving exposure to either lineage. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Novel roles for Arabidopsis dynamin-related proteins DRP1A and DRP2B in resistance against Botrytis cinerea fungal infection
- Author
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Grant Mc Gowan, Gayani Ekanayake, Robert A. Ingle, and Antje Heese
- Subjects
ccv ,dynamin ,fls2 ,flg22 ,plant immunity ,Plant ecology ,QK900-989 ,Biology (General) ,QH301-705.5 - Abstract
Arabidopsis DYNAMIN-RELATED PROTEIN1A (AtDRP1A) and AtDRP2B are large GTPases that function together in endocytosis for effective cytokinesis, cell enlargement and development. A recent study shows that these DRPs contribute to ligand-induced endocytosis of the immune receptor FLAGELLIN SENSING2 (AtFLS2) to modulate flg22-immune signaling, and they are required for immunity against Pseudomonas syringae pv. tomato bacteria. Here, we demonstrate that atdrp1a and atdrp2b single mutants showed increased susceptibility to Botrytis cinerea indicating that AtDRP1A and AtDRP2B are necessary for effective resistance against this necrotrophic fungus. Thus, we expanded our limited understanding of clathrin endocytic accessory proteins in immunity against plant pathogens.
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- 2022
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4. Coxiella burnetii inhibits nuclear translocation of TFEB, the master transcription factor for lysosomal biogenesis.
- Author
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Killips B, Heaton EJB, Augusto L, Omsland A, and Gilk SD
- Subjects
- Humans, Animals, Vacuoles metabolism, Vacuoles microbiology, Mice, Cell Nucleus metabolism, Protein Transport, Coxiella burnetii genetics, Coxiella burnetii metabolism, Coxiella burnetii physiology, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors metabolism, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors genetics, Lysosomes metabolism, Q Fever microbiology
- Abstract
Coxiella burnetii is a highly infectious, Gram-negative, obligate intracellular bacterium and the causative agent of human Q fever. The Coxiella Containing Vacuole (CCV) is a modified phagolysosome that forms through fusion with host endosomes and lysosomes. While an initial acidic pH < 4.7 is essential to activate Coxiella metabolism, the mature, growth-permissive CCV has a luminal pH of ~5.2 that remains stable throughout infection. Inducing CCV acidification to a lysosomal pH (~4.7) causes Coxiella degradation, suggesting that Coxiella regulates CCV pH. Supporting this hypothesis, Coxiella blocks host lysosomal biogenesis, leading to fewer host lysosomes available to fuse with the CCV. Host cell lysosome biogenesis is primarily controlled by the transcription factor EB (TFEB), which binds Coordinated Lysosomal Expression And Regulation (CLEAR) motifs upstream of genes involved in lysosomal biogenesis and function. TFEB is a member of the microphthalmia/transcription factor E (MiT/TFE) protein family, which also includes MITF, TFE3, and TFEC. This study examines the roles of MiT/TFE proteins during Coxiella infection. We found that in cells lacking TFEB, both Coxiella growth and CCV size increase. Conversely, TFEB overexpression or expression in the absence of other family members leads to significantly less bacterial growth and smaller CCVs. TFE3 and MITF do not appear to play a significant role during Coxiella infection. Surprisingly, we found that Coxiella actively blocks TFEB nuclear translocation in a Type IV Secretion System-dependent manner, thus decreasing lysosomal biogenesis. Together, these results suggest that Coxiella inhibits TFEB nuclear translocation to limit lysosomal biogenesis, thus avoiding further CCV acidification through CCV-lysosomal fusion., Importance: The obligate intracellular bacterial pathogen Coxiella burnetii causes the zoonotic disease Q fever, which is characterized by a debilitating flu-like illness in acute cases and life-threatening endocarditis in patients with chronic disease. While Coxiella survives in a unique lysosome-like vacuole called the Coxiella Containing Vacuole (CCV), the bacterium inhibits lysosome biogenesis as a mechanism to avoid increased CCV acidification. Our results establish that transcription factor EB (TFEB), a member of the microphthalmia/transcription factor E (MiT/TFE) family of transcription factors that regulate lysosomal gene expression, restricts Coxiella infection. Surprisingly, Coxiella blocks TFEB translocation from the cytoplasm to the nucleus, thus downregulating the expression of lysosomal genes. These findings reveal a novel bacterial mechanism to regulate lysosomal biogenesis., Competing Interests: The authors declare no conflict of interest.
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- 2024
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- View/download PDF
5. Human Rabies Vaccines
- Author
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Briggs, Deborah J., Hemachudha, Thiravat, and Ertl, Hildegund C.J., editor
- Published
- 2020
- Full Text
- View/download PDF
6. LES investigation of cycle-to-cycle variation in a SI optical access engine using TFM-AMR combustion model.
- Author
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Zembi, Jacopo, Battistoni, Michele, Nambully, Suresh Kumar, Pandal, Adrian, Mehl, Cédric, and Colin, Olivier
- Abstract
Multi-cycle large-eddy simulations (LES) are performed to investigate combustion cycle-to-cycle variability (CCV) in a gasoline spark ignited optical access engine operating under homogeneous stoichiometric conditions. Combustion is addressed with the Thickened Flame Model (TFM) and finite rate chemistry is accounted for through a reduced oxidation reaction mechanism. In view of the fact that computational costs of LES engine simulations are still very high today, this work investigates the use of adaptive mesh refinement (AMR) in the flame zone in conjunction with the artificial flame thickening applied by the TFM model. The paper discusses how the resulting coupled TFM-AMR combustion model allows good resolution of the flame, maintaining accuracy at acceptable costs. First, the details of the coupled model are presented and the effects of the parameters are explored, highlighting their impact on the combustion prediction. Then, computational fluid dynamics (CFD) simulation results are validated against experimental data collected in a low-speed low-load engine point, by comparing 20 LES cycles and 100 measured cycles, for mass fraction burned, combustion phasing, flame images and CCV indices. Lastly, a detailed investigation on the fastest and slowest numerical cycles is presented, analyzing instantaneous flame structures, ignition behaviors, propagation speeds, and probability density function (PDF) of the instantaneous velocity fluctuation around the spark region. The results show that combustion variability is highly correlated to the resolved velocity field and the resolved turbulence intensity, which is found to be the main cause of CCV and affects the early flame kernel growth. This work is an early attempt to use TFM-AMR combustion model for LES simulations of internal combustion engines. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
7. Alpha adaptins show isoform‐specific association with neurofibrillary tangles in Alzheimer's disease.
- Author
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Srinivasan, Sukanya, Gal, Jozsef, Bachstetter, Adam, and Nelson, Peter T.
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ALZHEIMER'S disease , *NEUROFIBRILLARY tangles , *GENETIC variation , *APOLIPOPROTEIN E4 , *SUBSPECIES , *IMMUNOHISTOCHEMISTRY , *TAU proteins - Abstract
Aims: The heterotetrameric assembly protein complex 2 (AP‐2) is a central hub for clathrin‐dependent endocytosis. The AP‐2 α‐adaptin subunit has two major isoforms, encoded by two separate genes: AP2A1 and AP2A2. Endocytosis has been implicated in the pathogenesis of neurodegenerative disease, and recent studies linked α‐adaptins (gene variants, splicing defects and altered expression) with late‐onset Alzheimer's disease (LOAD) risk. Here, we used multiple antibodies to investigate α‐adaptin isoforms and their localization in human brains. Methods: The specificities of 10 different α‐adaptin antibodies were evaluated using immunoblots after human AP2A1 and AP2A2 plasmid transfection in cultured cells. Additional immunoblot analyses were then performed on protein homogenates from control and LOAD subjects. Formalin‐fixed, paraffin‐embedded brain sections from control and LOAD subjects were immunohistochemically stained, and immunofluorescence experiments were performed for quantitation of colocalisation with digital image analysis. Results: Eight of the 10 evaluated antibodies recognised transfected α‐adaptin proteins on immunoblots. The α‐adaptin subspecies were relatively uniformly expressed in five different human brain regions. The α‐adaptins were present in the detergent‐insoluble fraction from cognitively impaired, but less so in control, brains. Immunohistochemical analyses showed colocalisation of AP2A1 with tau pathology in LOAD brains. By contrast, AP2A2 colocalised with microglial cells. Conclusions: These observations provide evidence of isoform‐specific changes of α‐adaptins in the brains of LOAD subjects. Antibodies that were verified to recognise AP2A1, but not AP2A2, labelled neurofibrillary tangles of LOAD patients. The findings extend our understanding of AP‐2 proteins in the human brain in healthy and diseased states. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
8. Machine Learning Application to Predict Combustion Phase of a Direct Injection Spark Ignition Engine.
- Author
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Asakawa, Rio, Yokota, Keisuke, Tanabe, Iku, Yamaguchi, Kyohei, Sok, Ratnak, Ishii, Hiroyuki, and Kusaka, Jin
- Subjects
- *
SPARK ignition engines , *MACHINE learning , *COMBUSTION , *ARTIFICIAL neural networks , *THERMAL efficiency , *LEAN combustion - Abstract
Lean-diluted combustion can enhance thermal efficiency and reduce exhaust gas emissions from spark-ignited (SI) gasoline engines. However, excessive lean mixture with external dilution leads to combustion instability due to high cycle-to-cycle variations (CCV). The CCV should be controlled as low as possible to achieve stable combustion, high engine performance, and low emissions. Therefore, a stable combustion control function is required to predict the combustion phase with a low calculation load. A machine learning-based function is developed in this work to predict the 50 % mass fraction burn location (MFB50). Input parameters to the machine learning model consist of 1-, 2-, 3-, and 4-cycle from a three-cylinder production-based gasoline engine operated under stoichiometric to the lean-burn mixture. The results show that the MFB50 prediction model achieves high accuracy when 2-cycle data are used relative to 1-cycle data, which implies that the previous cycle data affects the predicted MFB50 of the next cycle. As a result, the neural network model can predict the cyclic MFB50 error within ± 3 °CA CCV and ± 5 °CA CCV with 70 % and 90 % accuracy, respectively. However, an increasing number of cycle data worsens the prediction accuracy due to model over-learning. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. Pseudoangiosarcoma and cutaneous collagenous vasculopathy in a patient on a Bruton's tyrosine kinase inhibitor.
- Author
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Kucharik AH, Curkovic NB, Chavez JC, Tsai KY, Brohl AS, and Grichnik JM
- Abstract
Competing Interests: None disclosed.
- Published
- 2024
- Full Text
- View/download PDF
10. Experimental study on tri-fuel combustion using premixed methane-hydrogen mixtures ignited by a diesel pilot.
- Author
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Cheng, Qiang, Ahmad, Zeeshan, Kaario, Ossi, Vuorinen, Ville, and Larmi, Martti
- Subjects
- *
HYDROGEN flames , *DIESEL motor combustion , *COMBUSTION , *DIESEL motors , *THERMAL efficiency , *SEPARATION of variables , *WAVELET transforms - Abstract
A comprehensive investigation on diesel pilot spray ignited methane-hydrogen (CH 4 –H 2) combustion, tri-fuel combustion (TF), is performed in a single-cylinder compression ignition (CI) engine. The experiments provide a detailed analysis of the effect of H 2 concentration (based on mole fraction, M H2) and charge-air temperature (T air) on the ignition behavior, combustion stability, cycle-to-cycle (CCV) and engine performance. The results indicate that adding H 2 from 0 to 60% shortens the ignition delay time (IDT) and combustion duration (based on CA90) up to 33% and 45%, respectively. Thereby, H 2 helps to increase the indicated thermal efficiency (ITE) by as much as 10%. Furthermore, to gain an insight into the combustion stability and CCV, the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) methodologies are applied to estimate the combustion stability and CCV of the TF combustion process. The results reveal that the pressure oscillation can be reduced up to 4 dB/Hz and the CCV by 50% when M H2 < 60% and T air < 55 °C. However, when M H2 > 60% and T air > 40 °C, abnormal combustion and knocking are observed. • A comprehensive study on diesel pilot tri-fuel combustion has been conducted in a compression ignition engine. • The H 2 concentration and charge-air temperature were parametrically applied to study their effects on engine performance. • A short-time Fourier transfer method was employed to estimate the combustion stability. • A continuous wavelet transfer method was adopted to assess the cycle-to-cycle variations. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
11. Validation of a zonal hybrid URANS/ LES turbulence modeling method for multi-cycle engine flow simulation.
- Author
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Krastev, Vesselin Krassimirov, d'Adamo, Alessandro, Berni, Fabio, and Fontanesi, Stefano
- Abstract
A zonal hybridization of the RNG k-ε URANS model is proposed for the simulation of turbulent flows in internal combustion engines. The hybrid formulation is able to act as URANS, DES or LES in different zones of the computational domain, which are explicitly set by the user. The resulting model has been implemented in a commercial computational fluid dynamics code and the LES branch of the modified RNG k-ε closure has been initially calibrated on a standard homogeneous turbulence box case. Subsequently, the full zonal formulation has been tested on a fixed intake valve geometry, including comparisons with third-party experimental data. The core of the work is represented by a multi-cycle analysis of the TCC-III experimental engine configuration, which has been compared with the experiments and with prior full-LES computational studies. The applicability of the hybrid turbulence model to internal combustion engine flows is demonstrated, and PIV-like flow statistics quantitatively validate the model performance. This study shows a pioneering application of zonal hybrid models in engine-relevant simulation campaigns, emphasizing the relevance of hybrid models for turbulent engine flows. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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12. Aggressive Variants of Papillary Thyroid Carcinoma and Poorly Differentiated Carcinoma
- Author
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Baloch, Zubair W., LiVolsi, Virginia A., Wartofsky, Leonard, editor, and Van Nostrand, Douglas, editor
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- 2016
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13. Enhancement of Mean Shift Tracking Through Joint Histogram of Color and Color Coherence Vector
- Author
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Sidram, M. H., Bhajantri, N. U., Kacprzyk, Janusz, Series editor, Babu, B. V., editor, Nagar, Atulya, editor, Deep, Kusum, editor, Pant, Millie, editor, Bansal, Jagdish Chand, editor, Ray, Kanad, editor, and Gupta, Umesh, editor
- Published
- 2014
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14. Caching methodologies in Content centric networking (CCN): A survey.
- Author
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Lal, Nidhi, Kumar, Shishupal, Kadian, Garima, and Chaurasiya, Vijay Kumar
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INTERNET traffic ,CACHE memory ,INTERNET access ,METHODOLOGY ,INFORMATION networks ,CONTENT delivery networks ,INFORMATION retrieval - Abstract
Abstract Nowadays, Information centric networking has tremendous importance in accessing internet based applications. The increasing rate of Internet traffic has encouraged to adapt content centric architectures to better serve content provider needs and user demand of internet based applications which is based on receiver driven data retrieval. These architectures have built-in network Caches and these properties improves efficiency of content delivery with high speed and efficiency and they are very efficient in comparison with traditional caching of internet access methodologies. By using Information centric architectures, users need not download content from content server despite they can easily access data from nearby caches. User requested content is independent of the location of that data by use of caching approaches and does not rely on storage and transmission methodologies of that content. There has been many researches going to base on caching approaches in the Content centric network. Efficient caching is essential to reduce delay and to enhance performance of the network. Efficient caching is essential to reduce delay and to enhance performance of the network. So, in this paper, we presented a survey on caching approaches and related issues like cache content, availability, and cache router localization and so on. The main focus to present a state-of-art research paper for researchers who are interested in the area of Information centric network so that they can get an idea about what work and issues have been developed and arises in this particular caching field. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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15. Notes on the hybrid URANS/LES turbulence modeling for Internal Combustion Engines simulation.
- Author
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Krastev, V.K., Di Ilio, G., Falcucci, G., and Bella, G.
- Abstract
Abstract In the past 20 years, Large Eddy Simulation methods have continuously increased their popularity among the Internal Combustion Engines modeling community, due to their intrinsic potential in the description of the unsteady and randomly generated in-cylinder flow structures. Such capability has gained further relevance in the simulation of modern turbocharged GDI engines, where the high-fidelity resolution of cycle-to-cycle variability phenomena is crucial for the evaluation of the engine performance and emission trends. Nonetheless, even after many years of development the application of standard LES methods to full-scale engine geometries is still not straightforward, due to: the need for specific, turbulence-generating boundary conditions at open ends; more severe grid resolution/quality and time step requirements compared to unsteady RANS; the need for high-order (at least second-order accurate) numerical schemes. Therefore, a viable alternative might be found in hybrid URANS/LES turbulence modeling, which has the potential to achieve adequate scale-resolving levels wherever actually needed, but mitigating at the same time some of the aforementioned concerns. In the present work we discuss the current status and perspectives of URANS/LES hybrids in the ICE field, based on the scientific literature state-of-the art and on a series of previous computational studies made by the authors. Outcomes from this study essentially confirm that this class of methods deserve further attention and will likely support URANS and standard LES in the near future as an effective computational tool for the ICE development and optimization. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
16. Transcriptomic analysis reveals differentially expressed genes and a unique apoptosis pathway in channel catfish ovary cells after infection with the channel catfish virus.
- Author
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Dawar, Farman Ullah, Hu, Xianqin, Zhao, Lijuan, Dong, Xingxing, Xiong, Yang, Zhou, Meng, Liang, Rishen, Sarath Babu, V., Li, Jun, Mei, Jie, and Lin, Li
- Subjects
- *
CHANNEL catfish virus disease , *GENE expression in fishes , *APOPTOSIS , *VIRAL disease prevention , *RNA sequencing , *OVARIES - Abstract
The channel catfish virus (CCV) can cause lethal hemorrhagic infection in juvenile channel catfish, thereby resulting in a huge economic loss to the fish industry. The genome of the CCV has been fully sequenced, and its prevalence is well documented. However, less is known about the molecular mechanisms and pathogenesis of the CCV. Herein, the channel catfish ovary cells (CCO) were infected with CCV and their transcriptomic sketches were analyzed using an RNA sequencing technique. In total, 72,686,438 clean reads were obtained from 73,231,128 sequence reads, which were further grouped into 747,168 contigs. These contigs were assembled into 49,119 unigenes, of which 20,912 and 18,333 unigenes were found in Nr and SwissProt databases and matched 15,911 and 14,625 distinctive proteins, respectively. From these, 3641 differentially expressed genes (DEGs), comprising 260 up-regulated and 3381 down-regulated genes, were found compared with the control (non-infected) cells. For verification, 16 DEGs were analyzed using qRT-PCR. The analysis of the DEGs and their related cellular signaling pathways revealed a substantial number of DEGs that were involved in the apoptosis pathway induced by CCV infection. The apoptosis pathways were further elucidated using standard apoptosis assays. The results showed that CCV could induce extrinsic apoptosis pathway (instead of a mitochondrial intrinsic apoptosis pathway) in CCO cells. This study helps our understanding of the pathogenesis of CCV and contributes to the prevention of CCV infection in channel catfish. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
17. Experimental study on tri-fuel combustion using premixed methane-hydrogen mixtures ignited by a diesel pilot
- Author
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Zeeshan Ahmad, Martti Larmi, Ossi Kaario, Qiang Cheng, Ville Vuorinen, Department of Mechanical Engineering, Aalto-yliopisto, and Aalto University
- Subjects
Combustion stability ,Thermal efficiency ,Materials science ,Ignition behavior ,Hydrogen ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,Mole fraction ,Combustion ,01 natural sciences ,Methane ,law.invention ,Diesel fuel ,chemistry.chemical_compound ,law ,Engine performance ,Renewable Energy, Sustainability and the Environment ,Short-time Fourier transform ,CCV ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Tri-fuel ,Ignition system ,Fuel Technology ,chemistry ,0210 nano-technology - Abstract
Funding Information: The present study has been financially supported by the Academy of Finland (Grant Nos. 297248 and 318024 ) and Fortum-Neste Foundation (grant no. 2020050 ), which are gratefully acknowledged. The second author has also been financially supported by the Henry-Ford foundation under grant no. 202000063 . The authors are thankful to Ranta Olli and Blomstedt Otto for their supports on the engine preparations. Publisher Copyright: © 2021 The Authors A comprehensive investigation on diesel pilot spray ignited methane-hydrogen (CH4–H2) combustion, tri-fuel combustion (TF), is performed in a single-cylinder compression ignition (CI) engine. The experiments provide a detailed analysis of the effect of H2 concentration (based on mole fraction, MH2) and charge-air temperature (Tair) on the ignition behavior, combustion stability, cycle-to-cycle (CCV) and engine performance. The results indicate that adding H2 from 0 to 60% shortens the ignition delay time (IDT) and combustion duration (based on CA90) up to 33% and 45%, respectively. Thereby, H2 helps to increase the indicated thermal efficiency (ITE) by as much as 10%. Furthermore, to gain an insight into the combustion stability and CCV, the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) methodologies are applied to estimate the combustion stability and CCV of the TF combustion process. The results reveal that the pressure oscillation can be reduced up to 4 dB/Hz and the CCV by 50%when MH2 < 60% and Tair < 55 °C. However, when MH2 > 60% and Tair > 40 °C, abnormal combustion and knocking are observed.
- Published
- 2021
18. LES investigation of cycle-to-cycle variation in a SI optical access engine using TFM-AMR combustion model
- Author
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Cédric Mehl, Suresh Kumar Nambully, Adrian Pandal, Jacopo Zembi, Olivier Colin, and Michele Battistoni
- Subjects
cycle-to-cycle variation ,020209 energy ,spark ignition ,Aerospace Engineering ,Ocean Engineering ,02 engineering and technology ,Computational fluid dynamics ,Combustion ,large-eddy simulation ,020401 chemical engineering ,Spark (mathematics) ,TFM ,0202 electrical engineering, electronic engineering, information engineering ,adaptive mesh refinement ,0204 chemical engineering ,Aerospace engineering ,Gasoline ,thickened flame model ,business.industry ,Adaptive mesh refinement ,engine ,Mechanical Engineering ,CCV ,Homogeneous ,LES ,Automotive Engineering ,Environmental science ,business ,CFD ,Large eddy simulation - Abstract
Multi-cycle large-eddy simulations (LES) are performed to investigate combustion cycle-to-cycle variability (CCV) in a gasoline spark ignited optical access engine operating under homogeneous stoichiometric conditions. Combustion is addressed with the Thickened Flame Model (TFM) and finite rate chemistry is accounted for through a reduced oxidation reaction mechanism. In view of the fact that computational costs of LES engine simulations are still very high today, this work investigates the use of adaptive mesh refinement (AMR) in the flame zone in conjunction with the artificial flame thickening applied by the TFM model. The paper discusses how the resulting coupled TFM-AMR combustion model allows good resolution of the flame, maintaining accuracy at acceptable costs. First, the details of the coupled model are presented and the effects of the parameters are explored, highlighting their impact on the combustion prediction. Then, computational fluid dynamics (CFD) simulation results are validated against experimental data collected in a low-speed low-load engine point, by comparing 20 LES cycles and 100 measured cycles, for mass fraction burned, combustion phasing, flame images and CCV indices. Lastly, a detailed investigation on the fastest and slowest numerical cycles is presented, analyzing instantaneous flame structures, ignition behaviors, propagation speeds, and probability density function (PDF) of the instantaneous velocity fluctuation around the spark region. The results show that combustion variability is highly correlated to the resolved velocity field and the resolved turbulence intensity, which is found to be the main cause of CCV and affects the early flame kernel growth. This work is an early attempt to use TFM-AMR combustion model for LES simulations of internal combustion engines.
- Published
- 2022
19. Nonlinear time series analysis from large eddy simulation of an internal combustion engine.
- Author
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Keskinen, Jukka-Pekka, Vuorinen, Ville, and Kaario, Ossi
- Subjects
- *
NONLINEAR analysis , *TIME series analysis , *LARGE eddy simulation models , *INTERNAL combustion engines , *PARAMETER estimation - Abstract
Nonlinear time series analysis was applied for the first time to time series obtained from large eddy simulations (LES) of an internal combustion engine (ICE). The aim of the study was to obtain more information about the cycle-to-cycle variation (CCV) in the studied simplified ICE geometry than what is available from standard methods. Phase space reconstructions were created from the time series and then estimates for the largest Lyapunov exponent were calculated. The time delays used in the phase space reconstructions were determined using average mutual information while the proper embedding dimensions were chosen according to the method of false nearest neighbours. Quantitative information on the behaviour of the flow and the CCV was acquired from three-dimensional phase space reconstructions. Introduced modifications to the flow were clearly visible in the phase space reconstructions of energy and dissipation, indicating that these quantities are appropriate for monitoring and analysing the state of the system. The estimates for the largest Lyapunov exponents were positive for almost all time series, indicating chaotic dynamics. The permutation spectrum test was used to confirm the chaoticity of the CCV. The present results indicate that the used methods offer a promising new framework for characterising the CCV from the viewpoint of nonlinear time series analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. Scale-resolving simulations in engine combustion process design based on a systematic approach for model development.
- Author
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Hasse, Christian
- Abstract
The increasing availability of high-performance computing resources will allow scale-resolving simulations such as large eddy simulations to be used instead of unsteady Reynolds-averaged Navier–Stokes approaches, not only in academic research but also for engine combustion process development. The scope of this work is to highlight and discuss this transition to scale-resolving simulations and to propose a systematic approach for model development and application. The current and future scope of industrial and academic research is discussed especially with respect to cycle-to-cycle variations, which cannot be identified with unsteady Reynolds-averaged Navier–Stokes models. The individual processes along the cause-and-effect chain leading to cyclic variations of the combustion process are identified, and the current state of scale-resolving simulations and the required models with respect to these processes are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
21. Large-Eddy Simulation of Cycle-Resolved Knock in a Turbocharged SI Engine.
- Author
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d'Adamo, Alessandro, Breda, Sebastiano, and Cantore, Giuseppe
- Abstract
The paper presents a numerical study of cycle-to-cycle variability in a turbocharged GDI engine. The Large-Eddy Simulation technique is adopted in this study in conjunction with the recent ISSIM-LES model for spark-ignition, allowing a dedicated treatment of both the flame kernel formation and flame development phases. Numerical results are compared with an extended dataset of experimental test-bed acquisitions, where the engine is operated at knock-limited spark advance. The agreement of both ensemble averaged combustion pressure history and of its standard deviation confirm the validity of the adopted numerical framework able to correctly quantify the degree of CCV measured by the experiments.Knock tendency is evaluated by means of an in-house developed knock model, based on a tabulation technique for AI delays of the same RON98 gasoline as the one used in experiments. The results confirm the knock- free condition of the experimental KLSA, for which the cycle-resolved knock signature is extremely weak just for the cycles in the highest band of the CCV-affected combustion. The visualization of the pressure wave allows to identify the exhaust side as the most knock-prone region. Finally, spark-advance is increased by 3 CA with respect to the experimental edge-of knock limit, in order to simulate an experimentally prevented operating condition. Local pressure measurements mimicking flush-mounted transducers confirm the severe knock damage related to this condition. The predictive capability of the combustion CCV and of the adopted knock model confirm the heavy and recurrent cycle-resolved knock damage. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
22. Large-Eddy Simulation of Cycle-resolved Knock in a Turbocharged SI Engine.
- Author
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d’Adamo, Alessandro, Breda, Sebastiano, and Cantore, Giuseppe
- Abstract
The paper presents a numerical study of cycle-to-cycle variability in a turbocharged GDI engine. The Large-Eddy Simulation technique is adopted in this study in conjunction with the recent ISSIM-LES model for spark-ignition, allowing a dedicated treatment of both the flame kernel formation and flame development phases. Numerical results are compared with an extended dataset of experimental test-bed acquisitions, where the engine is operated at knock-limited spark advance. The agreement of both ensemble averaged combustion pressure history and of its standard deviation confirm the validity of the adopted numerical framework able to correctly quantify the degree of CCV measured by the experiments.Knock tendency is evaluated by means of an in-house developed knock model, based on a tabulation technique for AI delays of the same RON98 gasoline as the one used in experiments. The results confirm the knock-free condition of the experimental KLSA, for which the cycle-resolved knock signature is extremely weak just for the cycles in the highest band of the CCV-affected combustion. The visualization of the pressure wave allows to identify the exhaust side as the most knock-prone region. Finally, spark-advance is increased by 3 CA with respect to the experimental edge-of knock limit, in order to simulate an experimentally prevented operating condition. Local pressure measurements mimicking flush-mounted transducers confirm the severe knock damage related to this condition. The predictive capability of the combustion CCV and of the adopted knock model confirm the heavy and recurrent cycle-resolved knock damage. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
23. Environmental and economic assessment of life extension scenarios in electrical and electronic apparatus. Kettle application
- Author
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Sandez, Sonia, Bovea, María D, Ibáñez-Forés, valeria, and Pérez-Belis, Victoria
- Subjects
hervidor ,fin de vida ,circular economy ,economía circular ,durability ,CCV ,ACV ,kettle - Abstract
Ponencia presentada en: 25th International Congress on Project Management and Engineering Alcoi, 6th – 9th July 2021 El Nuevo Plan de Acción de Economía Circular fomenta, entre otros aspectos, el diseño de productos que mejoren su durabilidad, reutilizabilidad, actualizabilidad y reparabilidad, siendo la categoría de productos eléctricos y electrónicos, una de las prioritarias. En este contexto, y tomando como caso de aplicación los hervidores domésticos de agua (kettles), el objetivo de esta comunicación es proponer estrategias de fin de vida que fomenten su extensión de vida útil, y comparar su impacto ambiental y económico. Se han planteado 54 escenarios alternativos que permiten extender la vida útil de PAEE, aplicado al caso de estudio de hervidores. La configuración de los escenarios se ha realizado en base a la combinación de diferentes niveles de tres parámetros (nivel de uso, nivel de mantenimiento y momento de reemplazo de una pieza estropeada, con varios supuestos de duración del producto reparado). Cada uno de estos escenarios se ha analizado desde el punto de vista ambiental y económico, mediante la aplicación de las metodologías de Análisis de Ciclo de Vida y Coste del Ciclo de Vida. The New Circular Economy Action Plan encourages, among other aspects, the design of products that improve their durability, reusability, upgradeability and repairability, being the category of electrical and electronic equipment one of the priorities. In this context, and taking kettles as a case study, this communication aims to propose different end-of-life strategies that promote their useful life extension and to compare their environmental and economic impact. To this end, 54 alternative scenarios oriented to life-extension of small electrical and electronic equipment have been defined for kettles. These scenarios have been created through the combination of different levels of three parameters (level of use, level of maintenance and replacement time of a damaged part by considering different assumptions of the duration of the repaired product). Each scenario has been analyzed from an environmental and economic approach, by applying the Life Cycle Analysis and Life Cycle Cost methodologies.
- Published
- 2021
24. Validation of a zonal hybrid URANS/LES turbulence modeling method for multi-cycle engine flow simulation
- Author
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Stefano Fontanesi, Vesselin Krassimirov Krastev, Alessandro D'Adamo, and Fabio Berni
- Subjects
Turbulence ,zonal URANS ,LES ,multi-cycle ,CCV ,zonal URANS/LES ,Mechanical Engineering ,Flow (psychology) ,Turbulence modeling ,Aerospace Engineering ,Ocean Engineering ,Mechanics ,Combustion ,Settore ING-IND/08 ,Automotive Engineering ,Environmental science - Abstract
A zonal hybridization of the RNG [Formula: see text]-[Formula: see text] URANS model is proposed for the simulation of turbulent flows in internal combustion engines. The hybrid formulation is able to act as URANS, DES or LES in different zones of the computational domain, which are explicitly set by the user. The resulting model has been implemented in a commercial computational fluid dynamics code and the LES branch of the modified RNG [Formula: see text]-[Formula: see text] closure has been initially calibrated on a standard homogeneous turbulence box case. Subsequently, the full zonal formulation has been tested on a fixed intake valve geometry, including comparisons with third-party experimental data. The core of the work is represented by a multi-cycle analysis of the TCC-III experimental engine configuration, which has been compared with the experiments and with prior full-LES computational studies. The applicability of the hybrid turbulence model to internal combustion engine flows is demonstrated, and PIV-like flow statistics quantitatively validate the model performance. This study shows a pioneering application of zonal hybrid models in engine-relevant simulation campaigns, emphasizing the relevance of hybrid models for turbulent engine flows.
- Published
- 2019
25. Live Cell Imaging of Yeast Golgi Dynamics.
- Author
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Costaguta G, Payne GS, and Daboussi L
- Subjects
- Clathrin-Coated Vesicles, Golgi Apparatus, Clathrin, Saccharomyces cerevisiae, trans-Golgi Network
- Abstract
Fluorescence imaging of live cells allows for the observation of dynamic processes inside cells in real time. Here we describe a strategy to image clathrin-coated vesicle dynamics in a single focal plane at the trans-Golgi network of the yeast Saccharomyces cerevisiae. This method can be readily adapted for live cell imaging of a diverse set of dynamic processes within cells., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2023
- Full Text
- View/download PDF
26. Sero Epidemiological Study of Viral Gastroenteritis in Dogs by using Indirect ELISA.
- Author
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Deka, Devajani, Phukan, A., Sarma, D. K., Chakraborty, A. K., and Das, Sutopa
- Abstract
The article discusses findings of a study to determine the susceptibility of dogs to viral gastroenteritis using indirect enzyme-linked immunosorbent assay (ELISA) technique. It notes that the sero epidemiological study of canine parvovirus (CPV) and canine coronavirus (CCV) was conducted for 178 diarrhoeic dogs in Kamrup, India. It confirms the 100 percent sensitivity of indirect ELISA in 92.31 percent detection of anti-CPV antibody and 89.44 percent detection of CCV antibody.
- Published
- 2015
27. Coxiella burnetii control of the host transcription factors TFEB and TFE3
- Author
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Padmanabhan, Bhavna and Padmanabhan, Bhavna
- Abstract
Coxiella burnetii, the etiological agent of the zoonotic disease Q fever, is an obligate Gram-negative intracellular bacterial pathogen that replicates inside the lysosome-derived CCV (Coxiella-containing vacuole) within mammalian hosts. The CCV maintains the degradative and acidic nature of the host lysosome despite C. burnetii directing the massive expansion of this compartment to accommodate the replicating pathogen. To establish this unique replicative niche, C. burnetii requires the Dot/Icm type IV secretion system (T4SS). This T4SS translocates approximately 150 effectors into the host cell to modulate various cellular processes. To date, the functional role of very few of these effectors have been defined. Given the CCV’s origins it is not surprising that C. burnetii infection increases host autophagy and lysosome biogenesis. To investigate this at the protein level, we employed an elegant SILAC based proteome analysis of human cells infected with C. burnetii. This validated that many proteins involved in these processes are increased in abundance during infection. This prompted us to examine the role of the human transcription factor EB (TFEB) and its close homologue TFE3 during C. burnetii infection. TFEB is a master transcription regulator directly controlling the expression of a network of genes responsible for autophagy and lysosome biogenesis. 3 day’s post-infection with C. burnetii, TFEB/TFE3 is activated as demonstrated by TFEB/TFE3 trafficking from the cytoplasm into the nucleus. The nuclear translocation of TFEB/TFE3 appears to be controlled by C. burnetii as blocking bacterial translation with chloramphenicol leads to TFEB/TFE3 movement back into the cytoplasm. siRNA silencing of tfeb and tfe3 additionally demonstrated their contribution towards the intracellular success of C. burnetii. Interestingly, these host factors did not contribute to the replication of C. burnetii but in the absence of TFEB and TFE3 the CCV did not undergo its typical massi
- Published
- 2020
28. Novel roles for Arabidopsis dynamin-related proteins DRP1A and DRP2B in resistance against Botrytis cinerea fungal infection.
- Author
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Mc Gowan G, Ekanayake G, Ingle RA, and Heese A
- Subjects
- Botrytis, Clathrin metabolism, Clathrin pharmacology, Dynamins genetics, Dynamins metabolism, Flagellin pharmacology, Gene Expression Regulation, Plant, Ligands, Plant Diseases microbiology, Pseudomonas syringae, Arabidopsis metabolism, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Mycoses
- Abstract
Arabidopsis DYNAMIN-RELATED PROTEIN1A ( At DRP1A) and At DRP2B are large GTPases that function together in endocytosis for effective cytokinesis, cell enlargement and development. A recent study shows that these DRPs contribute to ligand-induced endocytosis of the immune receptor FLAGELLIN SENSING2 ( At FLS2) to modulate flg22-immune signaling, and they are required for immunity against Pseudomonas syringae pv. tomato bacteria. Here, we demonstrate that atdrp1a and atdrp2b single mutants showed increased susceptibility to Botrytis cinerea indicating that At DRP1A and At DRP2B are necessary for effective resistance against this necrotrophic fungus. Thus, we expanded our limited understanding of clathrin endocytic accessory proteins in immunity against plant pathogens.
- Published
- 2022
- Full Text
- View/download PDF
29. Evaluación de escenarios de fin de vida de pequeño aparato eléctrico y electrónico desde la perspectiva ambiental y económica. Aplicación a hervidores (Kettles)
- Author
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Sandez, Sonia, Ibáñez-Forés, valeria, Pérez-Belis, Victoria, and Bovea, María D
- Subjects
evaluación económica ,fin de vida ,evaluación ambiental ,CCV ,ACV - Abstract
Ponència presentada al IX Simposio Iberoamericano de Ingeniería de Residuos, Panamá, del 20 al 23 de setembre de 2021 El Nuevo Plan de Acción de Economía Circular fomenta, entre otros aspectos, el diseño de productos que incrementen su vida útil mediante la incorporación de requisitos de diseño relacionados con su reparabilidad, reutilizabilidad o actualizabilidad, siendo, la categoría de aparatos eléctricos y electrónicos, una de las prioritarias. En este contexto, y tomando como caso de aplicación los hervidores domésticos de agua, el objetivo de este estudio es identificar, desde el punto de vista ambiental y económico, la mejor alternativa de fin de vida si se ha producido un fallo en el aparato: sustituir o reparar y seguir utilizando. Para ello, se definen escenarios alternativos en función del tipo de fallo y el año en el que se produce el fallo. La información necesaria para modelar cada escenario se obtiene de la caracterización de componentes y materiales en el laboratorio de un aparato, y de bases de datos de reparación, servicios de atención al cliente o reparadores. Cada uno de los escenarios de fin de vida se analiza desde la perspectiva ambiental mediante la aplicación de la metodología de Análisis del Ciclo de Vida (ACV) y desde la perspectiva económica mediante la aplicación de la metodología de Coste del Ciclo de Vida (CCV).
- Published
- 2021
30. Large eddy simulation of a piston–cylinder assembly: The sensitivity of the in-cylinder flow field for residual intake and in-cylinder velocity structures.
- Author
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Keskinen, Jukka-Pekka, Vuorinen, Ville, Kaario, Ossi, and Larmi, Martti
- Subjects
- *
LARGE eddy simulation models , *SENSITIVITY analysis , *FLOW velocity , *PISTONS , *COMPUTATIONAL fluid dynamics software ,DESIGN & construction - Abstract
Large eddy simulation (LES) in an axisymmetric piston–cylinder geometry was carried out using three LES approaches: (1) Smagorinsky subgrid scale model, (2) implicit LES, and (3) scale selective discretisation (SSD). In addition to the LES subgrid scale model sensitivity study, two additional simulations were carried out in order to understand the roles of the intake and the in-cylinder residual turbulence to the flow statistics. Altogether 12 cycles were computed for each simulation on a grid with 5 million cells and requiring over a month of wall-clock time per simulation on a supercomputer. Analysis of velocity statistics revealed that the results were not very sensitive to the LES model type. However, the residual turbulence was noted to have a clear impact on the velocity statistics. In particular, the simulations revealed that removing the residual turbulence from the intake region at the top-dead-centre has a clear impact on the overall velocity statistics. In many cases the cycle-to-cycle variation (CCV) increased. In a respective numerical test, where only the in-cylinder turbulence was removed at top-dead-centre, weaker sensitivity was observed. In addition, the CCV relative to the mean velocity was in some cases as high as 30% even in such a non-reactive case. The present study complements previous studies on the same set-up by investigating the sensitivity of three LES models on flow statistics, quantifying CCV using three different LES approaches in the standard set-up, and assessing the role of residual turbulence on the flow statistics via modified flow cases. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
31. Cutaneous collagenous vasculopathy associated with intravascular occlusive fibrin thrombi.
- Author
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Salama, Samih, Chorneyko, Kathy, and Belovic, Brian
- Subjects
- *
INTRAVASCULAR ultrasonography , *OCCLUSIVE surgical dressings , *FIBRINOGEN , *TELANGIECTASIA , *HYPERPLASIA - Abstract
Cutaneous collagenous vasculopathy ( CCV) is a rare cutaneous microangiopathy that clinically resembles generalized essential telangiectasia with only 12 cases reported to date. The perivascular fibrosis is thought to be due to production of abnormal collagen by veil cells in the outer vessel walls as a result of unknown factors. This report is of an 84-year-old male with progressive telangiectasia. Biopsies showed characteristic features of CCV. In addition, there were multiple intravascular fibrin thrombi, some organizing and associated with endothelial cell hyperplasia with recanalization reminiscent of glomeruloid bodies and simulating reactive angioendotheliomatosis ( RAE). Histochemically and ultrastructurally fibrin was noted within the vessel walls integrating into the fibrous tissue around the vessels; however, the patient had no evidence of coagulation disorder, cryoglobulinemia or cold agglutinemia. Immunofluorescence showed fibrinogen within the vessel walls but no immunoglobulins or C3. As well, there were minimal inflammatory cells. This suggests pauci-inflammatory injury to the endothelial cells by unknown angiogenic factors causing local intravascular fibrin thrombi with fibrin leaking and incorporating into the vessel walls, eventually leading to reparative perivascular fibrosis. This case suggests that some cases of CCV are related to a primary local intravascular occlusive thrombotic microangiopathy. However, the primary triggering factor causing the endothelial cell damage has yet to be elucidated. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
32. Evaluation of the sustainability of structural sealing systems with and without coproducts of amethyst stone extraction
- Author
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Cadore, William Widmar, Isaia, Geraldo Cechella, Mancio, Mauricio, Silva, Maristela Gomes da, Wolff, Delmira Beatriz, and Grigoletti, Giane de Campos
- Subjects
Parede estrutural externa ,Economic and environmental sustainability ,External structural wall ,LCA ,Sustentabilidade econômica e ambiental ,LCC ,CCV ,Co-product of amethyst stone extraction ,Coproduto da extração da pedra ametista ,ENGENHARIAS::ENGENHARIA CIVIL [CNPQ] ,ACV - Abstract
The extraction of precious gemstones that for more than 30 years has transformed Ametista do Sul region, in the northwest of the state of Rio Grande do Sul, into the world hub producer of amethyst stone, has an environmental liability in the mining residues. The miner’s cooperative, COOGAMAI, has more than 220 gemstones mines registered in activities that generate more than 25 thousand tons of waste per month. A non-significant portion of this material is commercialized, falling under the concept of a co-product, while most demand suitable locations for disposal. Given this scenario, the objective of this paper was centered on verifying the economic and environmental potential of replacing aggregates such as sand and gravel by the co-product in comparisons of nine compositions of 1 m² external structural walls with concrete molded on site, structural masonry in concrete bricks and structural masonry in ceramic bricks, facing the methodologies of LCA (Life Cycle Assessment) and LCC (Life Cycle Cost), from the cradle to the grave. The environmental results of LCA indicate that the structural masonry walls, both in concrete an ceramic bricks, are more environmentally efficient than the ones with concrete molded on site. The co-product of the extraction of amethyst stone presents significant contributions in the reduction of environmental impacts, when total substitutions occur, as in the scenario P06 with reductions of 16% in global warming or 41% for the formation of particulate material. The wall with concrete molded on site P09, with 100% of amethyst co-product, also showed a 17% reduction in ozone depletion or 10% in fossil depletion. The economic compositions of LCC, indicate that concrete walls molded on site are 35% less expensive, on average, when compared to structural masonry walls. The global analysis of economic and environmental sustainability, allowed to identify the contribution of the co-product of amethyst stone, with reductions close to 5% between scenarios of the same constructive typology and a reduction of 20% in the P09 scenario, listed as the best performance, against the walls of structural masonry. Above all, the use of a coproduct from the extraction of amethyst stone presents conditions for replacing natural aggregates, even if in partial proportions. With this, it becomes an alternative source of income for the local chain, which, within a circular economy, at the same time, guarantees an efficient solution for the correct destination of waste from the extraction of precious stones. A extração de gemas preciosas que por mais de 30 anos transformou a região de Ametista do Sul, noroeste do estado do Rio Grande do Sul, no polo mundial, produtor da pedra ametista, possui nos resíduos do garimpo um passivo ambiental. A cooperativa de garimpeiros COOGAMAI, conta com o registro de mais de 220 garimpos em atividades que geram mensalmente mais de 25 mil toneladas de resíduos. Uma parcela não significativa desse material é comercializado, enquadrando-se no conceito de um coproduto, enquanto a maior parte demanda locais adequados para disposição. Atendendo a esse cenário, o objetivo centrou-se em verificar o potencial econômico e ambiental da substituição de agregados como areia e brita pelo coproduto em comparações de nove composições de 1 m² de parede estrutural de vedação externa em concreto moldado no local, alvenaria estrutural em blocos de concreto e alvenaria estrutural em blocos cerâmicos, frente as metodologias da ACV e CCV, do berço ao túmulo. Os resultados ambientais na ACV indicam que as paredes em alvenaria estrutural, tanto em blocos de concreto, quanto cerâmicos, são ambientalmente mais eficientes que em concreto moldado no local. O coproduto da extração da pedra ametista apresenta contribuições significativas nas reduções dos impactos ambientais, quando ocorrem substituições totais, a exemplo do cenário P06 com reduções de 16% no aquecimento global ou 41% para formação de material particulado. A parede de concreto moldado no local P09, com 100% de coproduto ametista também apresentou reduções de 17% na depleção do ozônio ou 10% na depleção fóssil. As composições econômicas da CCV, indicam que paredes de concreto moldado no local são 35% menos onerosas, em média, se comparadas às paredes de alvenaria estrutural. A análise global de sustentabilidade econômica e ambiental, permitiu identificar a contribuição do coproduto da pedra ametista, com reduções próximas de 5% entre cenários da mesma tipologia construtiva e diminuição de 20% no cenário P09, elencado como o melhor desempenho, frente às paredes de alvenaria estrutural. Sobretudo, o emprego de coproduto da extração de pedra ametista, apresenta condições para substituição dos agregados naturais, mesmo que em proporções parciais. Com isso, torna-se uma fonte de renda alternativa para a cadeia local, o que, dentro de uma economia circular, ao mesmo tempo garante uma solução eficiente para o destino correto dos resíduos da extração de pedras preciosas.
- Published
- 2020
33. UN’INDAGINE SULLA VARIABILITA’ CICLICA NEI MOTORI A COMBUSTIONE INTERNA UTILIZZANDO PROPER ORTHOGONAL DECOMPOSITION E LARGE-EDDY SIMULATIONS
- Author
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Rulli, Federico
- Subjects
Variabilità ciclica ,CCV ,ICE ,POD ,LES ,Turbolenza ,Settore ING-IND/08 - Macchine a Fluido - Published
- 2020
34. CCV
- Author
-
Schwab, Manfred, editor
- Published
- 2011
- Full Text
- View/download PDF
35. CCV
- Author
-
Schwab, Manfred, editor
- Published
- 2009
- Full Text
- View/download PDF
36. Implementation of External Quality Assessment Scheme in Clinical Chemistry for District Laboratories in Bhutan.
- Author
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Jamtsho, Rixin and Nuchpramool, Wilairat
- Abstract
External Quality Assessment Scheme (EQAS) involves evaluation of a number of laboratories by an outside agency on the performance of a number of laboratories based on their analytical performance of tests on samples supplied by the external agency. In developing countries, establishment of national EQAS by preparing homemade quality control material is a useful scheme in terms of resources and time to monitor the laboratory performance. The objective of this study is to implement an EQAS to monitor the analytical performance of the district laboratories in Bhutan. Baseline information was collected through questionnaires. Lyophilized human serum including normal and abnormal levels were prepared and distributed to 19 participating laboratories. Nine routine analytes were included for the study. Their results were evaluated using Variance index scores (VIS) and Coefficient of variations (CV) was compared with Clinical Laboratory Improvement Act (CLIA) Proficiency Testing Criteria (PT) for each analyte. There was significant decrease in CV at the end of the study. The percentages of results in acceptable VIS as 'A' were 63, 60, 66, 69, 73 and 74, 75, 76 and 79 % in November 2009-July 2010 respectively. From our results, we concluded that, establishment of EQAS through distribution of home-made quality control material could be the useful scheme to monitor the laboratory performance in clinical chemistry in Bhutan. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
37. Association of adaptor protein TRIP8b with clathrin.
- Author
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Popova, Nadezhda V., Deyev, Igor E., and Petrenko, Alexander G.
- Subjects
- *
PROTEIN-protein interactions , *CYTOSOL , *GUANOSINE triphosphatase , *G proteins , *ENDOSOMES , *ENDOCYTOSIS - Abstract
J. Neurochem. (2011) 118, 988-998. Abstract TPR-containing Rab8b-interacting protein (TRIP8b) is a brain-specific hydrophilic cytosolic protein that contains tetratricopeptide repeats (TPRs). Previous studies revealed interaction of this protein via its TPR-containing domain with Rab8b small GTPase, hyperpolarization-activated cyclic nucleotide-regulated channel (HCN) channels and G protein-coupled receptor calcium-independent receptor of α-latrotoxin. We identified clathrin as a major component of eluates from the TRIP8b affinity matrix. In the present study, by in vitro-binding analysis we demonstrate a direct interaction between clathrin and TRIP8b. The clathrin-binding site was localized in the N-terminal (non-TPR containing) part of the TRIP8b molecule that contains two short motifs involved in the clathrin binding. In transfected HEK293 cells, co-expression of HCN1 with TRIP8b resulted in translocation of the channels from the cell surface to large intracellular puncta where both TRIP8b and clathrin were concentrated. These puncta co-localized partially with an early endosome marker and strongly overlapped with lysosome staining reagent. When HCN1 was co-expressed with a clathrin-non-binding mutant of TRIP8b, clathrin did not translocate to HCN1 and TRIP8b-containing puncta, suggesting that TRIP8b interacts with HCN and clathrin independently. We found TRIP8b present in the fraction of clathrin-coated vesicles purified from brain tissues. Stripping the clathrin coat proteins from the vesicles with Tris alkaline buffer resulted in concomitant release of TRIP8b. Our data suggest complex regulatory functions of TRIP8b in neuronal endocytosis through independent interaction with membrane proteins and components of the clathrin coat. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
38. UBIQUITOUS REASSORTMENTS IN INFLUENZA A VIRUSES.
- Author
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WAN, XIU-FENG, OZDEN, MUFIT, and LIN, GUOHUI
- Subjects
- *
INFLUENZA A virus , *INFLUENZA viruses , *RNA polymerases , *NUCLEOPROTEINS , *NUCLEIC acids - Abstract
The influenza A virus is a negative-stranded RNA virus composed of eight segmented RNA molecules, including polymerases (PB2, PB1, PA), hemagglutinin (HA), nucleoprotein (NP), neuraminidase (NA), matrix protein (MP), and nonstructure gene (NS). The influenza A viruses are notorious for rapid mutations, frequent reassortments, and possible recombinations. Among these evolutionary events, reassortments refer to exchanges of discrete RNA segments between co-infected influenza viruses, and they have facilitated the generation of pandemic and epidemic strains. Thus, identification of reassortments will be critical for pandemic and epidemic prevention and control. This paper presents a reassortment identification method based on distance measurement using complete composition vector (CCV) and segment clustering using a minimum spanning tree (MST) algorithm. By applying this method, we identified 34 potential reassortment clusters among 2,641 PB2 segments of influenza A viruses. Among the 83 serotypes tested, at least 56 (67.46%) exchanged their fragments with another serotype of influenza A viruses. These identified reassortments involve 1,957 H2N1 and 1,968 H3N2 influenza pandemic strains as well as H5N1 avian influenza virus isolates, which have generated the potential for a future pandemic threat. More frequent reassortments were found to occur in wild birds, especially migratory birds. This MST clustering program is written in Java and will be available upon request. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
39. Clofibrate and gemfibrozil induce an embryonic malabsorption syndrome in zebrafish
- Author
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Raldúa, Demetrio, André, Michèle, and Babin, Patrick J.
- Subjects
- *
BLOOD lipids , *CLOFIBRATE , *ANTICHOLESTEREMIC agents - Abstract
Abstract: Nutrient availability is one of the major non-genetic factors determining embryonic growth and larval or fetal size. Due to the high human consumption of blood lipid regulators, fibrates have recently been reported as pollutants in rivers. Our study investigated the developmental toxicity of fibrates in zebrafish. Treatment with micromolar concentrations of clofibrate or gemfibrozil induced an embryonic malabsorption syndrome (EMS) with very little yolk consumption, resulting in small-sized larvae. This effect was reversible on removing the drug from the water. Clofibrate delayed hatching time and decreased the amount of oil red O lipid staining in the vasculature. It also induced higher density, round-shaped neuromuscular junctions associated with disorganization and less striation of muscular fibers, and pericardial edema, as well as impairing thyroid gland morphogenesis. acox1, apoa1 and mtp hybridization transcript signals were not affected in the yolk syncytial layer (YSL) after clofibrate exposure. Di-(2-ethylhexyl)-phthalate did not slow down yolk resorption, whereas brefeldin A induced EMS. These findings suggest that the inhibition of yolk sac resorption on exposure to fibrate is not at a pre-translational level or peroxisome proliferator-activated receptor alpha dependent and may be due to an inhibition of the YSL constitutive cell secretion. The effects of fibrates and the potential bioconcentration in eggs as well as the additive action of structurally related toxicants warrant an evaluation of the developmental impact of these compounds after long-term exposure at environmentally relevant concentrations. Fibrate-induced EMS in zebrafish seems useful for studying the morphogenetic consequences of impaired nutrient availability during the early stages of vertebrate development. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
40. Design and implementation of Web Services-based NGOSS technology-specific architecture.
- Author
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Choi, Mi-Jung, Ju, Hong-Taek, Hong, James, and Yun, Dong-Sik
- Abstract
To cope with frequent changes and functional additions of operation and support systems (OSSs), a guideline of OSS’s architecture and development methods is needed. TeleManagement Forum has provided Next Generation Operations Systems and Software (NGOSS) technology-neutral architecture (TNA), which describes major concepts and architectural details of the NGOSS architecture in a technologically neutral manner. The TNA can be mapped onto technology-specific architectures (TSAs) using specific technologies such as Extensible Markup Language, Java, and Common Object Request Broker Architecture. Web Service, a distributed and service-oriented computing technology, can be also applied to NGOSS TSA. In this paper, we provide a design and implementation of Web Services-based TSA in accordance with the architectural principles of TNA and the performance evaluation of our proposed system. Our work can be used as a guideline for anyone planning to develop a Web Services-based NGOSS TSA. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
41. First detection of channel catfish virus associated with mortality of cultured catfish ( Ictalurus punctatus, Rafinesque) in Mexico.
- Author
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Sánchez-Martínez, Jesús Genaro, Aguirre-Guzmán, Gabriel, de la Cruz-Hernández, Ned Ivan, Martínez-Burnes, Julio, Pérez-Castañeda, Roberto, Rábago-Castro, Jaime Luis, and de la Luz Vázquez-Sauceda, Maria
- Subjects
- *
CHANNEL catfish virus disease , *MORTALITY , *CHANNEL catfish , *HERPESVIRUS diseases in animals , *WATER quality management , *WATER pollution , *HIGH temperatures , *CATFISHES , *HISTOPATHOLOGY , *PHYSIOLOGY , *INTERNATIONAL trade - Abstract
The article discusses the detection of channel catfish virus (CCV) associated with mortality of cultured channel catfish in Mexico. The good quality of channel catfish' flesh and flavor has resulted the increase catfish consumption and growing fish farming industry. However, the detection of Herpesvirus ictaluri CCV was first isolated in the U.S. in 1960 that led the high mortality rates with significant economic losses of catfish industry. The histophathological examination has revealed multifocal necrotic areas and hemorrhage in the internal organs with viral infection.The CCV's infection is the most severe of the fish herpesvirus which proliferation was caused by stressful environmental conditions such as high temperature, low water quality, low oxygen level and poor feeding.
- Published
- 2007
- Full Text
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42. Aftiphilin is a component of the clathrin machinery in neurons
- Author
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Burman, Jonathon L., Wasiak, Sylwia, Ritter, Brigitte, de Heuvel, Elaine, and McPherson, Peter S.
- Subjects
- *
NEURONS , *NERVOUS system , *DATABASES , *INTERNET searching - Abstract
Abstract: Aftiphilin was identified through a database search for proteins containing binding motifs for the γ-ear domain of clathrin adaptor protein 1 (AP-1). Here, we demonstrate that aftiphilin is expressed predominantly in brain where it is enriched on clathrin-coated vesicles. In addition to eight γ-ear-binding motifs, aftiphilin contains two WXXF-acidic motifs that mediate binding to the α-ear of clathrin adaptor protein 2 (AP-2) and three FXXFXXF/L motifs that mediate binding to the α- and β2-ear. We demonstrate that aftiphilin uses these motifs for interactions with AP-1 and AP-2 and that it immunoprecipitates these APs but not AP-3 or AP-4 from brain extracts. Aftiphilin demonstrates a brefeldin A sensitive localization to the trans-Golgi network in hippocampal neurons where it co-localizes with AP-1. Aftiphilin is also found at synapses where it co-localizes with synaptophysin and AP-2. Our data suggest a role for aftiphilin in clathrin-mediated trafficking in neurons. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
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43. Notes on Asian stegodontids
- Author
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Saegusa, Haruo, Thasod, Yupa, and Ratanasthien, Benjavun
- Subjects
- *
SCIENCE museums , *PALEONTOLOGY , *BIOLOGY , *GEOLOGY - Abstract
Stegodontids, elephant-like proboscideans, flourished in the Neogene and Quaternary of Asia. The most significant recent finding in the study of stegodontids is the new stegodons and stegolophodons fossils from Nakhon Ratchasima, Thailand and Yuanmou Basin, Yunnan. Those specimens show a transition from stegolophodons to stegodons and support the idea that stegodons originated in Asia.Evolution of island forms from the mainland ancestral one is best documented in the Japanese islands. The following succession is present in Japan: S. zdanskyi, S. miensis, an intermediate form between S. miensis and S. aurorae, S. aurorae, and S. orientalis. The former three taxa represent a single lineage. The succession from S. zdanskyi to S. miensis may have been present also in the coastal area of China. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
44. Adaptación psicosocial del paciente oncológico ingresado y del familiar cuidador principal
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Lidia Abián, Hernán Cortés Funes, and Fabiola Cortés Funes
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Psychosocial adaptation ,Hospitalized oncologic patient ,Caregiver Familiar ,HAD ,Quality of life questionnaire ,CCV ,APGAR ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 ,Psychology ,BF1-990 - Abstract
The present study looks for the relation between the psychosocial distress experienced by the patient and his family caregiver during the period he is hospitalised. The sample is composed by 94 persons (oncology patients and family caregivers). We have used a sociodemographic questionnaire, the Hospital Anxiety and Depression Scale, the “Quality of life Questionnaire” for general satisfaction and social support and the family APGAR for family functioning. The results indicate that the anxiety of the caregiver is significantly higher than the one of the patient. The family functioning perceived by the patient correlates negatively with the depression and positively with the general satisfaction of the family caregiver. We found a correlation between the age and the depression subscale. In the family caregivers group we confirm that the higher scores in depression appear in ages between 35 and 55. Married patients and caregivers obtain higher punctuation in depression compared to unmarried ones. We conclude that the patients psychosocial distress differs from the caregivers distress. The psychological intervention should focus on the individual needs of the patient and the caregiver by promoting the social net of the relatives, supplying a better communication with the patient, reducing the caregivers anxiety and attending the demands derived from physical condition, marital status and age.
- Published
- 2003
45. Effect of handling stress on susceptibility of channel catfish Ictalurus punctatus to Ichthyophthirius multifiliis and channel catfish virus infection
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Davis, Kenneth B., Griffin, Billy R., and Gray, Wayne L.
- Subjects
- *
CHANNEL catfish , *ICHTHYOPHTHIRIUS , *PHYSIOLOGICAL stress - Abstract
A quantitative bioassay employing immersion exposure was developed for the infection of channel catfish Ictalurus punctatus with the protozoan parasite Ichthyophthirius multifiliis, commonly referred to as ich. This bioassay as well as waterborne challenge of channel catfish with channel catfish virus (CCV) was used to investigate the effect of confinement stress on the sensitivity of the fish to exposure of these pathogens. Infestation by ich was shown to be proportional to the density of infective theronts in the exposure tank and low-water crowding stress was shown to increase susceptibility of catfish to infection. Mortality from CCV was related to the virus exposure dose; however, low-water crowding stress did not affect mortality. Increased susceptibility, due to crowding stress of naı¨ve channel catfish to I. multifiliis but not to CCV, suggests a difference in the defence mechanisms. Stress-induced increased susceptibility to I. multifiliis may be due to a suppression of an innate protection mechanism. The lack of effect of stress on CCV mortality may be due to protection afforded by an inducible system which was not affected by the stressor, or the lethal effects of the virus were too fast for the stress to change susceptibility in fish exposed to CCV for the first time. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
46. Nonlinear time series analysis from large eddy simulation of an internal combustion engine
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Ossi Kaario, Jukka-Pekka Keskinen, Ville Vuorinen, Insinööritieteiden korkeakoulu, School of Engineering, Energiatekniikan laitos, Department of Energy Technology, Thermodynamics and Combustion Technology, Termodynamiikka ja polttotekniikka, Aalto-yliopisto, and Aalto University
- Subjects
DYNAMICS ,Technology ,chaos ,Chaotic ,Thermodynamics ,02 engineering and technology ,Lyapunov exponent ,01 natural sciences ,010305 fluids & plasmas ,symbols.namesake ,0203 mechanical engineering ,COMPRESSIBLE TURBULENCE ,0103 physical sciences ,Statistical physics ,SPARK-IGNITION ENGINE ,Mathematics ,Fluid Flow and Transfer Processes ,Energy ,ta214 ,Series (mathematics) ,ta213 ,engine ,Mechanical Engineering ,Physics ,IN-CYLINDER FLOW ,CCV ,Mutual information ,Dissipation ,Condensed Matter Physics ,Mechanical engineering ,020303 mechanical engineering & transports ,Flow (mathematics) ,Phase space ,LES ,symbols ,CHAOS ,DIESEL-ENGINE ,time series ,Large eddy simulation ,Engine ,Ttime series - Abstract
Julkaisun kokoteksti on luettavissa vain Aalto-tunnuksilla. Please note that access to the fulltext is limited to Aalto staff and students. Nonlinear time series analysis was applied for the first time to time series obtained from large eddy simulations (LES) of an internal combustion engine (ICE). The aim of the study was to obtain more information about the cycle-to-cycle variation (CCV) in the studied simplified ICE geometry than what is available from standard methods. Phase space reconstructions were created from the time series and then estimates for the largest Lyapunov exponent were calculated. The time delays used in the phase space reconstructions were determined using average mutual information while the proper embedding dimensions were chosen according to the method of false nearest neighbours. Quantitative information on the behaviour of the flow and the CCV was acquired from three-dimensional phase space reconstructions. Introduced modifications to the flow were clearly visible in the phase space reconstructions of energy and dissipation, indicating that these quantities are appropriate for monitoring and analysing the state of the system. The estimates for the largest Lyapunov exponents were positive for almost all time series, indicating chaotic dynamics. The permutation spectrum test was used to confirm the chaoticity of the CCV. The present results indicate that the used methods offer a promising new framework for characterising the CCV from the viewpoint of nonlinear time series analysis.
- Published
- 2016
47. Large-Eddy Simulation of Cycle-resolved Knock in a Turbocharged SI Engine
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Sebastiano Breda, Giuseppe Cantore, and Alessandro D'Adamo
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Engineering ,business.industry ,Combustion ,CCV ,Knock ,Mechanics ,knock ,Standard deviation ,Energy (all) ,Transducer ,Energy(all) ,LES ,Kernel (statistics) ,Spark (mathematics) ,Limit (music) ,business ,Simulation ,combustion ,Large eddy simulation ,Turbocharger - Abstract
The paper presents a numerical study of cycle-to-cycle variability in a turbocharged GDI engine. The Large-Eddy Simulation technique is adopted in this study in conjunction with the recent ISSIM-LES model for spark-ignition, allowing a dedicated treatment of both the flame kernel formation and flame development phases. Numerical results are compared with an extended dataset of experimental test-bed acquisitions, where the engine is operated at knock-limited spark advance. The agreement of both ensemble averaged combustion pressure history and of its standard deviation confirm the validity of the adopted numerical framework able to correctly quantify the degree of CCV measured by the experiments.Knock tendency is evaluated by means of an in-house developed knock model, based on a tabulation technique for AI delays of the same RON98 gasoline as the one used in experiments. The results confirm the knock-free condition of the experimental KLSA, for which the cycle-resolved knock signature is extremely weak just for the cycles in the highest band of the CCV-affected combustion. The visualization of the pressure wave allows to identify the exhaust side as the most knock-prone region. Finally, spark-advance is increased by 3 CA with respect to the experimental edge-of knock limit, in order to simulate an experimentally prevented operating condition. Local pressure measurements mimicking flush-mounted transducers confirm the severe knock damage related to this condition. The predictive capability of the combustion CCV and of the adopted knock model confirm the heavy and recurrent cycle-resolved knock damage.
- Published
- 2015
48. Sustainability of concrete with binary mixtures of pozolanas and concrete demolition waste emphasized in the evaluation and cost of the life cycle
- Author
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Lima, Cristian Jonathan Franco de, Isaia, Geraldo Cechella, Lübeck, André, and Mancio, Mauricio
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Pozolanas ,Agregado reciclado de concreto ,Recycled concrete aggregate ,CCV ,Environmental impacts ,Impactos ambientais ,ENGENHARIAS::ENGENHARIA CIVIL [CNPQ] ,ACV - Abstract
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES With the increasing consumption of natural resources worldwide, great concern about the environment is generated, making sustainability a focus on the quality of life and survival of living beings. In order to reduce these impacts, most segments of society have sought to rethink their production strategies, especially the construction industry, which is one of the largest consumers of natural resources, waste generators and harmful greenhouse gas emissions. In this context, the present study aims to study different concrete traces used for the design of a pillar, using two types of cement (CP IV and CP V-ARI), two types of pozolanas (rice husk ash and fly ash ), as well as a large aggregate of concrete demolition waste, in order to verify the main environmental impacts caused by each mix and to define the best concrete / pillar alternative from an environmental / sustainable and economic point of view. Previously, the traits to be used were defined, using the Abrams curve and dosage studies, and in a total of ten distinct traits, five were dosed at fck = 25MPa, and five dosed at fck = 35MPa; Afterwards, the moldings of the specimens were carried out according to the established traces, followed by the tests of Resistance to Axial Compression, Elasticity Modulus, Penetration of Chloride Ions by Immersion, Life Cycle Cost (CCV) and Cycle Analysis of Life (LCA). With respect to the Axial Compression Resistance, it was observed that the substitution of the natural aggregate (AGN) for recycled concrete aggregate (ARC) was detrimental, causing a significant decrease in resistance, which was counterbalanced by the use of pozzolans, as well as, alteration of the a / g ratios, and in the Modulus of Elasticity test a similar trend was observed. Regarding the durability, it was verified that the lower penetration coefficients of chloride ions, in general, occurred for the traces in which CP V cement was used, besides the partial replacement of the AGN by ARC in percentage of 15% and partial replacement of cement by pozolana in percentage of 25%. As for CCV and LCA, the cradle-to-grave approach was applied, thus, the pillars using concrete dosed to fck = 35MPa caused smaller impacts throughout its useful life. When the sustainability-financial integration was carried out, the pillar dosed at fck = 35MPa, using CP V cement, 15% of AGN replacement by ARC and substitution of 25% of cement per rice hull ash was obtained as the best alternative. Com o crescente aumento do consumo dos recursos naturais em nível mundial, geram-se grandes preocupações em relação ao meio ambiente, tornando a sustentabilidade um assunto em destaque quanto à qualidade de vida e a sobrevivência dos seres vivos. Com o intuito de reduzir esses impactos, grande parte dos segmentos da sociedade tem buscado repensar suas estratégias de produção, principalmente o setor da construção civil que é um dos maiores consumidores de recursos naturais, geradores de resíduos e emissões de gases prejudiciais do efeito estufa. Relacionado a este contexto, a presente pesquisa visa estudar diferentes traços de concreto utilizados para o dimensionamento de um pilar, utilizando dois tipos de cimento (CP IV e CP V- ARI), dois tipos de pozolanas (cinza de casca de arroz e cinza volante), bem como, agregado graúdo proveniente de resíduos de demolição de concreto, a fim de verificar os principais impactos ambientais causados por cada mistura e definir qual a melhor alternativa de concreto/pilar do ponto de vista ambiental/sustentável e econômico. Previamente foram definidos os traços a serem utilizados, por meio da curva de Abrams e estudos de dosagem, sendo que num total de dez traços distintos, cinco foram dosados para fck= 25MPa, e cinco dosados para fck= 35MPa; posteriormente, foram realizadas as moldagens dos corpos de prova de acordo com os traços estabelecidos, seguido dos ensaios de Resistência à Compressão Axial, Módulo de Elasticidade, Penetração de Íons Cloretos por Imersão, Custo do Ciclo de Vida (CCV) e Análise do Ciclo de Vida (ACV). No que diz respeito à Resistência a Compressão Axial, observou-se que a substituição do agregado graúdo natural (AGN) por agregado reciclado de concreto (ARC) foi prejudicial, causando significativa diminuição da resistência, a qual foi contrabalanceada com a utilização das pozolanas, bem como, alteração das relações a/ag, sendo que, no ensaio de Módulo de Elasticidade notou-se tendência semelhante. Em relação à durabilidade, verificou-se que os menores coeficientes de penetração de íons cloretos, de maneira geral, ocorreram para os traços em que se utilizou cimento CP V, além da substituição parcial do AGN por ARC em percentual de 15% e substituição parcial do cimento por pozolana em percentual de 25%. Quanto ao CCV e a ACV, foi efetuada a abordagem do berço ao túmulo (cradle-to-grave), assim, os pilares em que se empregou concreto dosado para fck= 35MPa causaram menores impactos ao longo de sua vida útil. Quando se realizou a integração sustentabilidade x financeiro, obteve-se como melhor alternativa o pilar dosado para fck= 35MPa, utilizando cimento CP V, 15% de substituição do AGN por ARC e substituição de 25% de cimento por cinza de casca de arroz.
- Published
- 2018
49. Notes on the hybrid URANS/LES turbulence modeling for Internal Combustion Engines simulation
- Author
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Gino Bella, Giacomo Falcucci, G. Di Ilio, and Vesselin Krassimirov Krastev
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business.industry ,Computer science ,Flow (psychology) ,CCV ,hybrid URANS/LES ,internal combution engines ,turbulence ,Turbulence modeling ,02 engineering and technology ,Combustion ,Grid ,01 natural sciences ,010305 fluids & plasmas ,020303 mechanical engineering & transports ,0203 mechanical engineering ,0103 physical sciences ,Settore ING-IND/08 - Macchine a Fluido ,Relevance (information retrieval) ,Aerospace engineering ,business ,Reynolds-averaged Navier–Stokes equations ,Large eddy simulation ,Turbocharger - Abstract
In the past 20 years, Large Eddy Simulation methods have continuously increased their popularity among the Internal Combustion Engines modeling community, due to their intrinsic potential in the description of the unsteady and randomly generated in-cylinder flow structures. Such capability has gained further relevance in the simulation of modern turbocharged GDI engines, where the high-fidelity resolution of cycle-to-cycle variability phenomena is crucial for the evaluation of the engine performance and emission trends. Nonetheless, even after many years of development the application of standard LES methods to full-scale engine geometries is still not straightforward, due to: the need for specific, turbulence-generating boundary conditions at open ends; more severe grid resolution/quality and time step requirements compared to unsteady RANS; the need for high-order (at least second-order accurate) numerical schemes. Therefore, a viable alternative might be found in hybrid URANS/LES turbulence modeling, which has the potential to achieve adequate scale-resolving levels wherever actually needed, but mitigating at the same time some of the aforementioned concerns. In the present work we discuss the current status and perspectives of URANS/LES hybrids in the ICE field, based on the scientific literature state-of-the art and on a series of previous computational studies made by the authors. Outcomes from this study essentially confirm that this class of methods deserve further attention and will likely support URANS and standard LES in the near future as an effective computational tool for the ICE development and optimization.
- Published
- 2018
50. A novel interpretation of min-max theorem and principle in relativistic quantum chemistry.
- Author
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Datta, Sambhu N.
- Subjects
DIRAC equation ,QUANTUM chemistry - Abstract
[Display omitted] • Rosicky-Mark variation optimizes u-l coupling in 4-spinor, creates energy maximum. • Variation of maximum with constrained component u (or l) gives an upper bound. • Steps together was named constrained component variation, is same as the min–max. • A new interpretation is that the coupling constraint restores Lorentz covariance. The development of min–max theorem and min–max principle for solving wave equations in relativistic quantum chemistry is briefly discussed. A new interpretation of the min–max treatment of Dirac equation is suggested. The min–max restores covariance in a one-electron formalism and tries to find a pure state. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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