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Timaxian, Colin, Christoph F. A. Vogel, Charlotte Orcel, Diana Vetter, Camille Durochat, Clarisse Chinal, Phuong NGuyen i in. "Pivotal Role for Cxcr2 in Regulating Tumor-Associated Neutrophil in Breast Cancer". Cancers 13, nr 11 (25.05.2021): 2584. http://dx.doi.org/10.3390/cancers13112584.
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Chemokines present in the tumor microenvironment are essential for the control of tumor progression. We show here that several ligands of the chemokine receptor Cxcr2 were up-regulated in the PyMT (polyoma middle T oncogene) model of breast cancer. Interestingly, the knock-down of Cxcr2 in PyMT animals led to an increased growth of the primary tumor and lung metastasis. The analysis of tumor content of PyMT-Cxcr2−/− animals highlighted an increased infiltration of tumor associated neutrophils (TANs), mirrored by a decreased recruitment of tumor associated macrophages (TAMs) compared to PyMT animals. Analysis of PyMT-Cxcr2−/− TANs revealed that they lost their killing ability compared to PyMT-Cxcr2+/+ TANs. The transcriptomic analysis of PyMT-Cxcr2−/− TANs showed that they had a more pronounced pro-tumor TAN2 profile compared to PyMT TANs. In particular, PyMT-Cxcr2−/− TANs displayed an up-regulation of the pathways involved in reactive oxygen species (ROS) production and angiogenesis and factors favoring metastasis, but reduced apoptosis. In summary, our data reveal that a lack of Cxcr2 provides TANs with pro-tumor effects.
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Benson, Douglas D., Xianzhong Meng, David A. Fullerton, Ernest E. Moore, Joon H. Lee, Lihua Ao, Christopher C. Silliman i Carlton C. Barnett. "Activation state of stromal inflammatory cells in murine metastatic pancreatic adenocarcinoma". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 302, nr 9 (1.05.2012): R1067—R1075. http://dx.doi.org/10.1152/ajpregu.00320.2011.
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The histologic presence of macrophages (tumor-associated macrophages, TAMs) and neutrophils (tumor-associated neutrophils, TANs) has been linked to poor clinical outcomes for solid tumors. The exact mechanism for this association with worsened prognosis is unclear. It has been theorized that TAMs are immunomodulated to an alternatively activated state and promote tumor progression. Similarly, TANs have been shown to promote angiogenesis and tumor detachment. TAMs and TANs were characterized for activation state and production of prometastatic mediators in an immunocompetent murine model of pancreatic adenocarcinoma. Specimens from liver metastases were evaluated by immunofluorescence and immunoblotting. TAMS have upregulated expression of CD206 and CD163 markers of alternative activation, (4.14 ± 0.55-fold and 7.36 ± 1.13-fold over control, respectively, P < 0.001) but do not have increased expression of classically activated macrophage markers CCR2 and CCR5. TAMs also express oncostatin M (OSM). We found that TANs, not TAMs, predominantly produce matrix metalloproteinase-9 (MMP-9) in this metastatic tumor microenvironment, while MMP-2 production is pan-tumoral. Moreover, increased expression of VEGF colocalized with TAMs as opposed to TANs. TAMs and TANs may act as distinct effector cells, with TAMs phenotypically exhibiting alternative activation and releasing OSM and VEGF. TANs are localized at the invasive front of the metastasis, where they colocalize with MMP-9. Improved understanding of these interactions may lead to targeted therapies for pancreas adenocarcinoma.
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Zhou, Zhengjun, Pengcheng Wang, Rongqi Sun, Jia Li, Zhiqiang Hu, Haoyang Xin, Chubin Luo, Jian Zhou, Jia Fan i Shaolai Zhou. "Tumor-associated neutrophils and macrophages interaction contributes to intrahepatic cholangiocarcinoma progression by activating STAT3". Journal for ImmunoTherapy of Cancer 9, nr 3 (marzec 2021): e001946. http://dx.doi.org/10.1136/jitc-2020-001946.
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BackgroundTumor-associated neutrophils (TANs) and macrophages (TAMs) can each influence cancer growth and metastasis, but their combined effects in intrahepatic cholangiocarcinoma (ICC) remain unclear.MethodsWe explored the distributions of TANs and TAMs in patient-derived ICC samples by multiplex immunofluorescent staining and tested their separate and combined effects on ICC in vitro and in vivo. We then investigated the mechanistic basis of the effects using PCR array, western blot analysis and ELISA experiments. Finally, we validated our results in a tissue microarray composed of primary tumor tissues from 359 patients with ICC.ResultsThe spatial distributions of TANs and TAMs were correlated with each other in patient-derived ICC samples. Interaction between TANs and TAMs enhanced the proliferation and invasion abilities of ICC cells in vitro and tumor progression in a mouse xenograft model of ICC. TANs and TAMs produced higher levels of oncostatin M and interleukin-11, respectively, in co-culture than in monoculture. Both of those cytokines activated STAT3 signaling in ICC cells. Knockdown of STAT3 abolished the protumor effect of TANs and TAMs on ICC. In tumor samples from patients with ICC, increased TAN and TAM levels were correlated with elevated p-STAT3 expression. All three of those factors were independent predictors of patient outcomes.ConclusionsTANs and TAMs interact to promote ICC progression by activating STAT3.
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Han, Booyeon Julia, Luis I. Ruffolo, Katherine M. Jackson, Brian A. Belt, Nathania Figueroa, Joseph D. Murphy, David Linehan i Peter A. Prieto. "Investigating the tumor-immune microenvironment in an autochthonous murine model of cholangiocarcinoma." Journal of Clinical Oncology 37, nr 8_suppl (10.03.2019): 53. http://dx.doi.org/10.1200/jco.2019.37.8_suppl.53.
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53 Background: Cholangiocarcinoma (CCA) is the most common liver malignancy within the biliary tree with increasing incidence and poor survival. Although surgical resection can be curative, prognosis remains abysmal with high rates of unresectability and recurrence, and new systemic therapies are needed. CCA tumors are characterized by an abundant inflammatory immune cell infiltrate, yet little is known about the immune dynamics underlying the disease. Here, we present a preclinical murine model of CCA for identifying potential targets susceptible to immune-based therapies. Methods: Mice with targeted activation of KrasG12D and loss of p53 (Kras-p53-/-) in the liver were exposed to 5-Diethoxycarbonyl-1.4-dihydrocollidine for 4 weeks to induce spontaneous CCA tumorigenesis. Immunohistochemistry staining was performed for mouse and human CCA. Immune compartments (bone marrow, spleen, peripheral blood, tumor draining and non-draining lymph nodes, and CCA tumor) of mice were processed for CyTOF analysis. In vitro assays of isolated myeloid leukocytes were performed to demonstrate function. Results: Tumor associated neutrophils (TANs) and tumor associated macrophages (TAMs) were present in high levels in human CCA tumors and the murine model. CyTOF analysis demonstrated mobilization of TANs, TAMs, and CCR2+ inflammatory monocytes into the tumor. The checkpoint marker PD-1 was upregulated on CD8+ and CD4+ T cells and associated with PD-L1+ TANs, TAMs, monocytes, and dendritic cells. The immunosuppressive tumor microenvironment was also characterized by TAMs expressing IL-10, TGFβ, and arginase 1; regulatory B cells expressing IL-10 and TGFβ; and Gata3+ TH2 cells. Isolated myeloid leukocytes suppressed T cell proliferation and induced invasive migration. Conclusions: Kras-p53-/- mice developed CCA tumors histologically similar to human disease: the data portray immunosuppressive cells in the tumor microenvironment, a possible obstacle for an effective anti-tumor response. Understanding the immune dynamics of immunosuppressive populations within the tumor microenvironment will be key to mount a potent therapeutic response for durable remission and improved survival.
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Ashby, F. Gregory, i Matthew J. Crossley. "A Computational Model of How Cholinergic Interneurons Protect Striatal-dependent Learning". Journal of Cognitive Neuroscience 23, nr 6 (czerwiec 2011): 1549–66. http://dx.doi.org/10.1162/jocn.2010.21523.
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An essential component of skill acquisition is learning the environmental conditions in which that skill is relevant. This article proposes and tests a neurobiologically detailed theory of how such learning is mediated. The theory assumes that a key component of this learning is provided by the cholinergic interneurons in the striatum known as tonically active neurons (TANs). The TANs are assumed to exert a tonic inhibitory influence over cortical inputs to the striatum that prevents the execution of any striatal-dependent actions. The TANs learn to pause in rewarding environments, and this pause releases the striatal output neurons from this inhibitory effect, thereby facilitating the learning and expression of striatal-dependent behaviors. When rewards are no longer available, the TANs cease to pause, which protects striatal learning from decay. A computational version of this theory accounts for a variety of single-cell recording data and some classic behavioral phenomena, including fast reacquisition after extinction.
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McAteer, Emily, i Simone Pulver. "The Corporate Boomerang: Shareholder Transnational Advocacy Networks Targeting Oil Companies in the Ecuadorian Amazon". Global Environmental Politics 9, nr 1 (luty 2009): 1–30. http://dx.doi.org/10.1162/glep.2009.9.1.1.
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Transnational advocacy networks (TANs) targeting corporations differ from those targeting states in the strategies they employ, determinants of network effectiveness, and assessments of goal achievement. This article develops a corporate boomerang model to analyze the dynamics of corporate-focused TANs. The model is used to assess two case studies of corporate-focused TANs—targeting the US-based oil corporations Chevron and Burlington Resources—active in Ecuador's Amazon region. In both TANs, corporate shareholder activists played a central role in the networks. The comparison demonstrates that the success of the Burlington TAN relative to the Chevron TAN can be explained by differences in the cohesiveness of the two networks and in the vulnerability of the two targets.
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Beniwal, Angad, Saket Jain, Sumedh Shah, Sabraj Gill, Garima Yagnik, Alan Nguyen, Harsh Wadhwa, Aaron Diaz i Manish K. Aghi. "TAMI-38. TUMOR-ASSOCIATED NEUTROPHILS IN GLIOBLASTOMA PROMOTE THE PERIVASCULAR GLIOMA STEM-LIKE CELL NICHE VIA OSTEOPONTIN SECRETION". Neuro-Oncology 23, Supplement_6 (2.11.2021): vi206. http://dx.doi.org/10.1093/neuonc/noab196.822.
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Abstract Among clinical analyses, elevated neutrophil-lymphocyte ratio has been correlated with poor outcomes of glioblastoma patients independent of other prognostic factors. Additionally, our flow cytometric studies of primary patient samples found neutrophil percentage to be significantly higher in higher-grade glioma versus lower-grade glioma. Tumor-associated neutrophils (TANs) comprise less than 2% of the glioblastoma microenvironment. While TANs were initially considered passive bystanders due to their short-lived nature, investigation of TANs in other cancers revealed distinct pro-tumoral roles. Therefore, we transcriptomically characterized glioblastoma TANs and defined their oncologic effects. Transcriptomic analysis of patient-matched TANs versus peripheral blood neutrophils revealed that functionally quiescent circulating neutrophils infiltrate IDH1-wild type glioblastoma via leukotriene B4 chemoattraction, where tumor cells morphologically and transcriptomically activate them to become TANs. Single-cell RNA-sequencing of patient-matched TANs and peripheral blood neutrophils revealed a subset of tumor-activated neutrophils which adopt a pro-tumoral secretory phenotype, marked by activation of the IL-17 signaling pathway and high osteopontin production. Using immunofluorescence stains of primary patient glioblastoma sections, we demonstrated that activated, myeloperoxidase-positive TANs reside in the perivascular niche of glioblastoma in close proximity to glioblastoma stem-like cells (GSCs) and CD31-positive endothelial cells. Further analysis in culture demonstrated that TAN-secreted osteopontin drives the formation, self-renewal, and proliferation of GSC-containing neurospheres. These results were validated using a syngeneic stem cell-derived IDH1-wild type murine glioblastoma model in vivo. Thus, while TANs are rare in glioblastoma, their enrichment in the glioblastoma perivascular niche uniquely positions them to support the GSCs that are crucial to therapeutic resistance of GBM.
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Vannitamby, Amanda, Mohamed I. Saad, Christian Aloe, Hao Wang, Beena Kumar, Ross Vlahos, Stavros Selemidis i in. "Aspirin-Triggered Resolvin D1 Reduces Proliferation and the Neutrophil to Lymphocyte Ratio in a Mutant KRAS-Driven Lung Adenocarcinoma Model". Cancers 13, nr 13 (28.06.2021): 3224. http://dx.doi.org/10.3390/cancers13133224.
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Tumour-associated neutrophils (TANs) can support tumour growth by suppressing cytotoxic lymphocytes. AT-RvD1 is an eicosanoid that can antagonise neutrophil trafficking instigated by ALX/FPR2 ligands such as serum amyloid A (SAA). We aimed to establish whether SAA and ALOX5 expression associates with TANs and investigate the immunomodulatory actions of AT-RvD1 in vivo. MPO-positive neutrophils were quantified in tumour blocks from lung adenocarcinoma (n = 48) and control tissue (n = 20) by IHC. Tumour expression of SAA and ALOX5 were analysed by RTqPCR and an oncogenic KrasG12D lung adenocarcinoma mouse model was used to investigate the in vivo efficacy of AT-RvD1 treatment. ALOX5 expression was markedly reduced in lung adenocarcinoma tumours. The SAA/ALOX5 ratio strongly correlated with TANs and was significantly increased in tumours harbouring an oncogenic KRAS mutation. AT-RvD1 treatment reduced tumour growth in KrasG12D mice, which was accompanied by suppressed cellular proliferation within parenchymal lesions. In addition, AT-RvD1 significantly reduced the neutrophil to lymphocyte ratio (NLR), an established prognostic marker of poor survival in adenocarcinoma. This study identifies a novel molecular signature whereby elevated levels of SAA relative to ALOX5 favour accumulation of TANs. Furthermore, the ALOX5/5-LO enzymatic product, AT-RvD1, markedly reduced the NLR and suppressed tumour growth in KrasG12D mice.
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Tan, Can Ozan, i Daniel Bullock. "A Dopamine–Acetylcholine Cascade: Simulating Learned and Lesion-Induced Behavior of Striatal Cholinergic Interneurons". Journal of Neurophysiology 100, nr 4 (październik 2008): 2409–21. http://dx.doi.org/10.1152/jn.90486.2008.
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The giant cholinergic interneurons of the striatum are tonically active neurons (TANs) that respond with pauses to appetitive and aversive cues and to novel events. Whereas tonic activity emerges from intrinsic properties of these neurons, glutamatergic inputs from intralaminar thalamic nuclei and dopaminergic inputs from midbrain are required for genesis of pause responses. No prior computational models encompass both intrinsic and synaptically gated dynamics. We present a mathematical model that robustly accounts for behavior-related electrophysiological properties of TANs in terms of their intrinsic physiological properties and known afferents. In the model, balanced intrinsic hyperpolarizing and depolarizing currents engender tonic firing and glutamatergic inputs from thalamus (and cortex) both directly excite and indirectly inhibit TANs. If this inhibition, probably mediated by GABAergic nitric oxide synthase interneurons, exceeds a threshold, a persistent K+ conductance current amplifies its effect to generate a prolonged pause. Dopamine (DA) signals modulate both the intrinsic mechanisms and the external inputs of TANs. Simulations revealed that many learning-dependent behaviors of TANs, including acquired pauses to task-relevant cues, are explicable without recourse to learning-dependent changes in synapses onto TANs, due to a tight coupling between DA bursts and TAN pauses. These interactions imply that reward-predicting cues often cause striatal projection neurons to receive a cascade of signals: an adaptively scaled DA burst, a brief acetylcholine (ACh) burst, and an ACh pause. A sensitivity analysis revealed a unique TAN response surface, which shows that DA inputs robustly cooperate with thalamic inputs to control cue-dependent pauses of ACh release, which strongly affects performance- and learning-related dynamics in the striatum.
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Lad, Meeki, Angad Beniwal, Saket Jain, Sabraj Gill i Manish Aghi. "TMIC-59. GLIOBLASTOMA INDUCES THE DIFFERENTIATION AND RECRUITMENT OF NON-CANONICAL ANTI-TUMORAL NEUTROPHILS FROM SKULL BONE MARROW". Neuro-Oncology 24, Supplement_7 (1.11.2022): vii284—vii285. http://dx.doi.org/10.1093/neuonc/noac209.1103.
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Abstract The effects of tumor-associated neutrophils (TANs) on glioblastoma biology remain poorly understood. Flow cytometric analysis of 5 newly diagnosed glioblastoma fresh tissue specimens surprisingly revealed a high fraction (21.0-34.1%) of TANs expressed MHCII, a marker of antigen-presenting cells not classically associated with neutrophils and not expressed in matched peripheral blood (PBNs). Transcriptomic profiling confirmed that patient TANs upregulated expression of MHCII subunits (HLA-DR), chaperones (HLA-DM), and costimulatory ligands (CD86/83). Ex vivo cocultures further demonstrated that TANs activated patient-matched naïve T cells in an MHCII-dependent manner, while PBNs did not (CD25 MFI fold-change: 1.1 vs 3.2, p< 0.001). The antitumoral relevance of this property was confirmed in a syngeneic mouse glioma model, wherein αLy6G-mediated neutrophil depletion in T-cell-competent mice (Balb/c, n= 13) yielded endpoint tumors that had reduced CD8+ T cell infiltration (p= 0.0024) and were 2.4-fold larger by BLI (p= 0.0383) than controls, but had no bearing on tumor burden in T-cell-deficient (athymic) mice. Given the absence of MHCII+ neutrophils in circulation, we interrogated the inducibility of this phenotype by tumor-conditioned media in murine marrow/blood, finding that only immature Ly6Glow bone marrow neutrophils had sufficient plasticity to express MHCII and process foreign antigen as measured by DQ-ovalbumin uptake/proteolysis. Because of the non-inducibility of PBNs, we investigated the hypothesis that MHCII+ TANs were recruited to the glioblastoma microenvironment from adjacent skull bone marrow by labeling this space with CFMDA in tumor-implanted mice; at 72h, skull marrow-derived neutrophils contributed disproportionately to MHCII+ TANs compared to all TANs (41.7% vs 9.3%). As confirmation, in the first-ever scRNA-seq of human TANs, we demonstrated via pseudotime analysis that MHCII+ neutrophils represent a developmental lineage seen in TANs but not matched PBNs. Given the immunostimulatory effects of this population, mechanisms to promote neutrophil egress and tumor infiltration from the skull marrow may have therapeutic value.
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Zheng, Wei, Jingjing Wu, Yao Peng, Jing Sun, Pu Cheng i Qi Huang. "Tumor-Associated Neutrophils in Colorectal Cancer Development, Progression and Immunotherapy". Cancers 14, nr 19 (29.09.2022): 4755. http://dx.doi.org/10.3390/cancers14194755.
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The colorectal-cancer (CRC) incidence rate and mortality have remained high for several years. In recent years, immune-checkpoint-inhibitor (ICI) therapy has rapidly developed. However, it is only effective in a few CRC patients with microsatellite-instability-high (MSI-H) or mismatch-repair-deficient (dMMR) CRC. How to improve the efficiency of ICI therapy in CRC patients with microsatellite stability (MSS) remains a huge obstacle. Tumor-associated neutrophils (TANs), which are similar to macrophages, also have N1 and N2 phenotypes. They can be recruited and polarized through different cytokines or chemokines, and then play an antitumor or tumor-promoting role. In CRC, we find that the prognostic significance of TANs is still controversial. In this review, we describe the antitumor regulation of TANs, and their mechanism of promoting tumor progression by boosting the transformation of inflammation into tumors, facilitating tumor-cell proliferation, metastasis and angiogenesis. The targeting of TANs combined with ICIs may be a new treatment model for CRC. Relevant animal experiments have shown good responses, and clinical trials have also been carried out in succession. TANs, as “assistants” of ICI treatment, may become the key to the success of CRC immunotherapy, although no significant results have been obtained.
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Yee, Patricia, Yiju Wei, Zhijun Liu, Hui Guo, Umeshkumar Manjibhai Vekariya, Benjamin Anderson i Wei Li. "TMIC-15. HYPERACTIVATING THE HIPPO PATHWAY EFFECTOR TAZ DIFFERENTIALLY DISTORTS THE TUMOR MICROENVIRONMENT, PROMOTES TUMOR-ASSOCIATED NEUTROPHIL INFILTRATION, AND PHENOCOPIES MESENCHYMAL-GLIOBLASTOMA". Neuro-Oncology 21, Supplement_6 (listopad 2019): vi250. http://dx.doi.org/10.1093/neuonc/noz175.1049.
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Abstract Glioblastoma (GBM), the deadliest and most common adult brain malignancy, is molecularly and clinically heterogeneous. The most common subtype (both primary and recurrent), mesenchymal (MES)-GBM, has the worst prognosis and highest treatment resistance. MES-GBM exhibits hyperactive transcriptional coactivator with PDZ-binding motif (TAZ), a Hippo tumor suppressive pathway effector whose expression in GBMs predicts short survival. Yet, how Hippo-TAZ dysregulation might drive GBM MES transition remains elusive, precluding subtype-specific treatments. Tumor evolution requires signaling dysregulation and co-opting the tumor microenvironment (TME). Understanding GBM heterogeneity was recently complicated by the notion that subtypes vary in TME immune composition. The MES-GBM TME is differentially-distorted in silico, with more tumor-associated macrophages/microglia (TAMs) and neutrophils (TANs). Yet, how TAZ hyperactivity, MES transition, and GBM TME distortion interrelate and impact tumor progression remains unknown. We suspected that TME distortion facilitates immune evasion, MES transition, and tumor progression, worsening treatment responses. To test this, we devised an orthotopic xenograft mouse model phenotypically and histopathologically recapitulating human MES-GBM by expressing constitutively-active TAZ (TAZ4SA) in human GBM cells lacking MES signatures (GBM4SA). GBM4SA mice lived significantly shorter compared to mice with GBM expressing vector (GBMvector) or mutant TAZ unable to bind its effector, TEAD (GBM4SA-S51A). Moreover, more myeloid cells infiltrate the GBM4SA TME than the GBMvector or GBM4SA-S51A TMEs. While most myeloid cells infiltrating the GBMvector and GBM4SA-S51A TMEs were TAMs, most infiltrating the GBM4SA TME were TANs, suggesting TAZ hyperactivation differentially distorts the TME. Next, to delineate the roles of TANs in GBM4SA tumor progression, mice were depleted of neutrophils by administering Ly6G antibody. Serial blood smears and flow cytometry revealed effective depletion was achieved. We are currently investigating the impact of systemic neutrophil depletion on GBM mesenchymal transition and tumor progression in hopes of informing future GBM clinical management and novel TME-targeted immunotherapies.
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Schauten, M. B. J., i B. Tans. "The implied cost of capital of government’s claim and the present value of tax shields: A numerical example". Applied Finance Letters 3, nr 1 (30.06.2014): 40. http://dx.doi.org/10.24135/afl.v3i1.20.
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This paper provides a numerical example of how to calculate the cost of capital of government’s claim (rg) and the present value of tax shields. Schauten and Tans (2006) show for the models used in Myers (1974), Miles and Ezzell (1980) and Harris and Pringle (1985), that the present value of tax shields is equal to the difference between the present value of the expected taxes paid by the unlevered firm and the levered firm, with each of the models’ implied rg as discount rate. We discuss a numerical example using the valuation framework by Schauten and Tans (2006) and give a logic explanation for the low implied rgs of Miles and Ezzell’s and Harris and Pringle’s model.
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Wang, Chuncheng. "AI-Based Heterogenous Large-Scale English Translation Strategy". Mobile Information Systems 2022 (9.02.2022): 1–10. http://dx.doi.org/10.1155/2022/8344814.
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English has become one of the most widely used languages in the world. If there is no good translation mechanism for such a widely used language, it will bring trouble to both study and life. At present, the world’s major platforms are committed to the study of English translation strategies. There are translation platforms from different regions and different translation mechanisms. These translation data from different translation platforms have the characteristics of large-scale, multisource, heterogeneity, high dimensions, and poor quality. However, such inconsistent translation data will increase the translation difficulty and translation time. Therefore, it is necessary to improve the quality of translation data to achieve a better translation effect. How to provide a large-scale and efficient translation strategy needs to integrate the translation strategies of various platforms to perform heterogeneous translation data cleaning and fusion based on machine learning. At first, this paper represents the multisource, heterogeneous translation data model as tree-augmented naive Bayes networks (TANs) and naturally captures the relationship between the datasets through the learning of TANs structure and the probability distribution of input attributes and tuples, using data probability value to complete the classification of translation data cleaning. Then, a multisource, heterogeneous translation data fusion model based on recurrent neural network (RNN) is constructed, and RNN is used to control the node data of hidden layer to enhance the fault-tolerant ability in the fusion process and complete the construction of fusion model. Finally, experimental results show that TANs-based translation data cleaning method can effectively improve the cleaning rate with an average improvement of approximately 10% and cleaning time with an average reduce about 5%. In addition, RNN-based multisource translation data fusion method improves the shortcomings of the traditional fusion model and improves the practicability of the fusion model in terms of root mean square error (RMSE), mean absolute percentage error (MAPE), fusion time, and integrity.
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George, Jason T., David A. Kessler i Herbert Levine. "Effects of thymic selection on T cell recognition of foreign and tumor antigenic peptides". Proceedings of the National Academy of Sciences 114, nr 38 (5.09.2017): E7875—E7881. http://dx.doi.org/10.1073/pnas.1708573114.
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The advent of cancer immunotherapy has generated renewed hope for the treatment of many malignancies by introducing a number of novel strategies that exploit various properties of the immune system. These therapies are based on the idea that cytotoxic T lymphocytes (CTLs) directly recognize and respond to tumor-associated neoantigens (TANs) in much the same way as they would to foreign peptides presented on cell surfaces. To date, however, nearly all attempts to optimize immunotherapeutic strategies have been empirical. Here, we develop a model of T cell selection based on the assumption of random interaction strengths between a self-peptide and the various T cell receptors. The model enables the analytical study of the effects of selection on the CTL recognition of TANs and completely foreign peptides and can estimate the number of CTLs that can detect donor-matched transplants. We show that negative selection thresholds chosen to reflect experimentally observed thymic survival rates result in near-optimal production of T cells that are capable of surviving selection and recognizing foreign antigen. These analytical results are confirmed by simulation.
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Luo, Wei, Huiting Lin, Zhihao Wu, Jingteng Chen, Ruiyang Chi, Xiaoxia Ye i Jie Chen. "Preparation and Physicochemical Properties of Tannin-Immobilized Membrane Adsorbent". Applied Sciences 11, nr 20 (17.10.2021): 9684. http://dx.doi.org/10.3390/app11209684.
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Plant tannins have the ability to form stable complexes with metal ions, while microporous membranes have low pressure drop and high flux characteristics. Combining these two materials, a new type of tannin-immobilized membrane (M-TAN) adsorption material has been developed. The PA-BWT, PVDF-BWT, CELL -BWT, and PA-AA-BWT were prepared using different types of microporous membranes as substrates, which maintained the porous structure of the membranes and had the characteristics of high flux and fast filtration rate. The surface contact angle and pure water flux analysis showed that the introduction of tannin with multi-phenolic hydroxyl groups increased the hydrophilicity and water flux of the M-TANs. The adsorption performance shows that the adsorption capacity of four kinds of M-TANs for UO22+ is in the order of PA-BWT > PA-AA-BWT > PVDF-BWT > CELL-BWT, and PA-BWT has the largest adsorption capacity of 0.398 mmol g−1. In addition, the adsorption isothermal and kinetic data of PA-BWT were well fitted by the Langmuir equation and the Elovich model, respectively. The negative values of ΔG for UO22+ adsorption on PA-BWT indicated that adsorption is a spontaneous and favorable process. These facts indicate that PA-BWT can be used as a low-cost adsorbent for effective removal of UO22+ from aqueous solutions.
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Jin, Lin, Jing Yang, Zhujun Yi, Hong S. Kim, Feng Tian i Jiaqi Shi. "Abstract PO-125: The role of KDM6A in pancreatic cancer immune microenvironment". Cancer Research 81, nr 22_Supplement (15.11.2021): PO—125—PO—125. http://dx.doi.org/10.1158/1538-7445.panca21-po-125.
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Abstract Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the United States, with a 10% 5-year survival rate. Immunosuppressive myeloid cells, including tumor-associated neutrophils (TANs), contribute to tumor development and treatment resistance. Lysine (K)-specific demethylase 6A (KDM6A) is one of the most frequently mutated epigenetic genes and a tumor suppressor in PDAC. However, the molecular mechanisms by which KDM6A contributes to PDAC development and whether KDM6A impacts the tumor immune microenvironment are unknown. This study established a genetically engineered pancreas-specific Kdm6a-knockout Ptf1aCre;LSL-KrasG12D/+;LSL-p53R172H/+ (KPC) PDAC mouse model to investigate the influence of KDM6A loss on PDAC development and tumor immune microenvironment. We found that KDM6A loss accelerated PDAC progression and increased metastases. Pancreata of mice with Kdm6a deficiency developed aggressive undifferentiated PDACs. Additionally, KDM6A loss led to increased infiltration of TANs and neutrophil extracellular traps (NETs) formation. Mechanistically, we used Bru-seq technology to investigate the impact of KDM6A on nascent RNA transcription. We demonstrated that many chemotactic cytokines related to neutrophil recruitment, specifically CXCL1, were upregulated in KDM6A-knockout PDAC cells. We further confirmed increased CXCL1 mRNA and protein levels in KDM6A-deficient human and mouse PDAC cells. In addition, immunohistochemical staining also confirmed the upregulated CXCL1 expression in both human and murine PDAC cells with KDM6A loss. TANs were found to express CXCR2, the receptor of CXCL1, by immunofluorescent analysis. To further confirm that cancer cells with KDM6A loss can attract neutrophils in vitro, we performed chemotaxis assays using both human neutrophils derived from PLB-985 cells and mouse primary neutrophils isolated from bone marrow and conditioned media from KDM6A- knockout or knockdown PDAC cells. We found that PDAC cells with KDM6A loss promoted neutrophil recruitment in vitro compared to KDM6A-retained PDAC cells. Furthermore, the CXCL1 neutralizing antibody reversed the chemotactic property of KDM6A-deficient PDAC cells, confirming that CXCL1 is the primary chemokine mediating the neutrophil recruitment. In summary, these findings shed light on the mechanism by which KDM6A loss promotes PDAC development, regulates tumor immune microenvironment, and suggests that the CXCL1-CXCR2 axis may be a candidate target for the treatment of PDAC, especially those with KDM6A mutations. Citation Format: Lin Jin, Jing Yang, Zhujun Yi, Hong S. Kim, Feng Tian, Jiaqi Shi. The role of KDM6A in pancreatic cancer immune microenvironment [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-125.
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FUJITA, S., Y. TAKATO i A. SUZUKI. "THEORY OF THE ELECTRICAL TRANSPORT IN METALLIC SINGLE-WALL NANOTUBES". Modern Physics Letters B 25, nr 04 (10.02.2011): 223–42. http://dx.doi.org/10.1142/s0217984911025675.
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A metallic (semiconducting) single-wall nanotube contains an irrational (integral) number of carbon hexagons in the pitch. The room-temperature conductivity is higher by two to three orders of magnitude in metallic nanotubes than in semiconducting nanotubes. Tans et al. [Nature386 (1997) 474] measured the electrical currents in metallic single-wall carbon nanotubes under bias and gate voltages, and observed non-Ohmic behaviors. The original authors interpreted their data in terms of a ballistic transport due to the Coulomb blockage on the electron-carrier model. The mystery of why a ballistic electron is not scattered by impurities and phonons is unexplained, however. An alternate interpretation is presented based on the Cooper pair (pairon)–carrier model. Superconducting states are generated by the Bose–Einstein condensation of the ± pairons at momenta 2πℏn/L, where L is the tube length and n a small integer. As the gate voltage changes the charging state of the tube, the superconducting states jump between different n. The normal current peak shapes appearing in the transition are found to be temperature-dependent, which is caused by the electron–optical phonon scattering.
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Kriegler, S. M. "Opleiding van opvoedkundige sielkundiges vir die bevordering van geestesgesondheid in Suid-Afrika". South African Journal of Psychology 18, nr 3 (wrzesień 1988): 84–90. http://dx.doi.org/10.1177/008124638801800303.
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Sielkundiges speel 'n uiters beperkte rol in prioriteitsbesluitnemingsprosesse en die bevordering van geestesgesondheid in die gemeenskap. In 'n land wat gekenmerk word deur sosio-ekonomiese en tegnologiese ontwikkelingsuiterstes en afstuur op dramatiese politieke veranderings en 'n moontlike geestesgesondheidskrisis, moet die sielkunde in die algemeen en die opvoedkundige sielkunde in die besonder deurslaggewende besluite neem rakende professionele rolverruiming, meer toepaslike intervensiemodelle en statutêre aanpassings. Opvoedkundige intervensiemodelle en vaardighede moet die ontoepaslike en koste-oneffektiewe, individuele, kuratiewe mediese model aanvul as die maatskaplike relevansie van die professie bewys wil word deur betrokkenheid by gemeenskapsontwikkeling, primêre voorkoming en nie-formele en informele onderwysprogramme. Die Suid-Afrikaanse opvoedkundige sielkunde staan vandag voor die enorme uitdaging om beroepslui op te lei wat onmisbare lede van môre se geestes-gesondheidspan sal wees. Die implikasie hiervan is 'n herstrukturering van bestaande opleidingsmodelle, doelwitte en inhoude en moontlik ook van die hiërargie van professionele registrasiekategorieë soos dit tans daar uitsien.
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Lebedev, M. A., i R. J. Nelson. "Rhythmically Firing Neostriatal Neurons in Monkey: Activity Patterns During Reaction-Time Hand Movements". Journal of Neurophysiology 82, nr 4 (1.10.1999): 1832–42. http://dx.doi.org/10.1152/jn.1999.82.4.1832.
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While previous studies have identified rhythmically firing neurons (RFNs) in monkey neostriatum and these rhythmic firing patterns have been shown to evolve in neostriatal tonically active neurons (TANs) after dopamine input depletion, the activity patterns of RFNs during motor behavior are still far from completely understood. We examined the single-unit activity patterns of neostriatal neurons, recorded in awake behaving monkeys during a wrist movement task, for evidence of rhythmic activity. Monkeys made ballistic wrist flexion and extension movements in response to vibrotactile cues. Animals held a steady wrist position for 0.5 to 2.0 s while awaiting the onset of the go-cues (hold period). Although the majority of neostriatal neurons (274/306) did not fire rhythmically, approximately 10% of the neurons (32/306) fired rhythmically at 10–50 Hz during the hold period. Most RFNs (28/32) showed significant activity changes during the time between go-cue presentation and movement onset (premovement activity). One-half of RFNs exhibited premovement activity that differed as a function of movement direction. Only one RFN may have responded to the delivery of a fruit juice reward. Neuronal firing was analyzed using interspike interval distributions, autocorrelations, and serial correlation techniques. These analyses showed that the activity patterns of most RFNs were consistent with an integrate-and-fire model of neuronal rhythm generation. Changes in RFN activity patterns during the premovement interval and intertrial variations in firing frequency could be explained by changes in the general level of excitatory input. These observations are consistent with the firing properties reported for neostriatal cholinergic interneurons. It has been suggested that tonically active neurons may be cholinergic interneurons and that these neurons show changes in activity related to specific aspects of behavioral paradigms, such as rewards. RFNs may constitute a special class of TANs. The results presented here suggest that RFNs may have a role in movement initiation. We speculate that RFNs may modulate the propagation of cortical oscillations via basal ganglia-thalamic-cortical loops.
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Kaul, Mitresh, i K. Nallasivam. "Response of Elevated Water Tanks Subjected to Lateral Loads". Civil and Environmental Engineering Reports 32, nr 2 (1.06.2022): 118–31. http://dx.doi.org/10.2478/ceer-2022-0022.
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Abstract During previous earthquakes around the world, it was discovered that elevated water tanks were severely damaged or collapsed. As a result, structural engineers are concerned about the analysis of these structures to gain a better understanding of the effects of seismic loads on elevated water tanks. In the current study, E-Tabs software, which is based on finite elements, is used to model various shapes of elevated water tanks along with various staging patterns. The higher stiffness of the supports in cross staging tanks makes them better than normal staging tanks, according to the results of the analysis. Furthermore, circular tanks perform better than other tank shapes when subjected to seismic loads. The study looks at water tanks subjected to static seismic loads. More research is needed to determine the analysis results for the dynamic seismic loads applied to the structure. All the analysis results are derived from the software’s tank analysis results.
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Saria, Abdellali, Mohamed Djermane i Nasser Dine Hadj-Djelloul. "Three-Dimensional Nonlinear Dynamic Analysis of Base Isolated Cylindrical Steel Tank". Civil Engineering Journal 8, nr 6 (1.06.2022): 1268–87. http://dx.doi.org/10.28991/cej-2022-08-06-013.
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Failure of a tank during an earthquake can result in significant financial, human, and environmental losses. Thus, their lack of resiliency against strong earthquakes may result in refinery disruption. This has the potential to have a considerable impact on any economic system. As a result, more research into the seismic performance of tank structures is required to attain the highest possible level of resistance against strong earthquakes. In this paper, we aim to look into the installation of seismic isolation systems in cylindrical steel storage tanks. A nonlinear 3D finite element model is developed with ANSYS software. Moreover, tank wall material nonlinearity, fluid-structure-interaction, and sloshing components are considered. The bilinear hysteretic LRB is used for modal and time-history analysis. In this work, three tanks with varying aspect ratios are studied: "Model A", "Model B", and "Model C". Furthermore, the fixed tank's fundamental frequencies were compared to the analytical results of the American API 650 Standard. Subsequently, the dynamic behavior response of the researched tanks to the horizontal component of the El-Centro 1940 earthquake with PGAs of 0.34g and 0.5g is investigated. As a result, the dominating frequency of the seismic isolation system is within the effective frequency range of seismically isolated systems. The results illustrate that the base isolation limits the tank wall movement with a large displacement in the isolators; the mode shape is a cantilever beam in all isolated circumstances. The total seismic response reduction in the slender tanks is greater as compared to the broad case in the base-isolated tanks. The sloshing displacement increases with an increase in the tank aspect ratio. Additionally, the isolation device eliminates tank buckling at the base and top of the tank shell during seismic excitation (elephant foot and diamond buckling). It can be concluded that the seismic isolation technique has a more significant impact on reducing the dynamic response of ground-supported tanks, particularly in taller tanks as compared to broad tanks. Doi: 10.28991/CEJ-2022-08-06-013 Full Text: PDF
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Yazdani, Hamza O., Tony Haykal, Ruiqi Yang, Celine Tohme, David A. Geller i Samer Tohme. "Abstract 5136: Surgical stress promotes long-lasting protumorigenic changes in bone marrow derived progenitor cells". Cancer Research 83, nr 7_Supplement (4.04.2023): 5136. http://dx.doi.org/10.1158/1538-7445.am2023-5136.
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Abstract Introduction: Surgery is a crucial intervention for cancer patients. However, the perioperative period is characterized by an increased risk for accelerated growth of metastatic disease. Our recent work shows that the protumorigenic systemic inflammatory changes and the formation of neutrophil extracellular traps (NETs) persist months after surgery in both mice and humans, and parallel micrometastatic tumor growth and recurrence. Here we hypothesized that surgery may induce long-term sustained epigenetic and transcriptomic changes in bone marrow derived granulocytes-monocytes progenitor cells (GMPs) leading to functional reprogramming of mature neutrophils and persistent systemic release of these protumorigenic NET-forming neutrophils. Methods: Eight-week-old mice were subjected to non-lethal surgical stress (laparotomy) for 30 mins. Seven days after, mice were inoculated with 1x106 MC38 (murine colorectal cancer cells) subcutaneously. For bone marrow (BM) transplant model, a group of B6 congenic (CD45.1) mice were subjected to laparotomy. BM derived cells were harvested 7 days after the procedure and orthotopically transplanted into B6 CD45.2 irradiated (1000 rads) mice. After the establishment of hematopoiesis (6 weeks), MC38 cancer cells were implanted into the recipient mice. Results: Mice that underwent laparotomy had significantly increased tumor volume at 3 weeks compared to control mice, that only underwent anesthesia (Laparotomy vs control **p<0.01). While the intratumoral flowcytometry analysis showed no difference in the frequency of infiltrating immune cells, quantitative (q) PCR analysis revealed significant plasticity in the tumor infiltrating neutrophils (TANs) observed by an increase in the expression of genes (MCP1, Arg1) associated with pro-inflammatory (N2) type neutrophils compared to control. A persistent increased level of NETs was also observed within the tumors and circulation of mice several weeks after laparotomy. ATAC-seq and Bulk-RNA-seq analysis further revealed major epigenetic and transcriptomic changes in TANs, circulating neutrophils and GMPs. To substantiate long-lasting surgical effects, tumor burden was assessed in the BM recipient mice and showed to be significantly increased in mice that had received BM cells from laparotomy mice versus BM cells from sham group. Conclusion: Surgery promotes long-term rewiring of the bone marrow derived cells resulting in increased tumor growth. Understanding the underlying molecular mechanism may help with therapeutic interventions to prevent protumorigenic surgical effects and improve patient outcomes. Citation Format: Hamza O. Yazdani, Tony Haykal, Ruiqi Yang, Celine Tohme, David A. Geller, Samer Tohme. Surgical stress promotes long-lasting protumorigenic changes in bone marrow derived progenitor cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5136.
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Qi, Li Mei, i Ming Deng Shi. "Study on Tank Capacity Table Measuring Model after the Storage Tank Displacement". Applied Mechanics and Materials 333-335 (lipiec 2013): 14–21. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.14.
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All of the gas station has established underground storage tanks in accordance with the unified state standards. Due to the reasons such as deformation of foundation many tanks occurs the longitudinal tilt and lateral deflection changed after a period of time in use that lead to tank capacity charts to change. This paper solves the storage tank displacements recognition and capacity charts calibration by mathematical modeling method and MATLAB software. We study the calibration tank capacity charts when actual storage tank happen vertical or horizontal displacements on the basis of research on small elliptic cylinder oil tank.
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Saravanathamizhan, R., R. Paranthaman, N. Balasubramanian i C. Ahmed Basha. "Tanks in Series Model for Continuous Stirred Tank Electrochemical Reactor". Industrial & Engineering Chemistry Research 47, nr 9 (maj 2008): 2976–84. http://dx.doi.org/10.1021/ie071426q.
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Li, Xian-Sheng, Yuan-Yuan Ren i Xue-Lian Zheng. "Model-Free Adaptive Control for Tank Truck Rollover Stabilization". Mathematical Problems in Engineering 2021 (20.08.2021): 1–16. http://dx.doi.org/10.1155/2021/8417071.
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Influenced by lateral liquid sloshing in partially filled tanks, tank vehicles are apt to encounter with rollover accidents. Due to its strong nonlinearity and loading state uncertainty, it has great challenges in tank vehicle active control. Based on the model-free adaptive control (MFAC) theory, the roll stability control problem of tank trucks with different tank shapes and liquid fill percentages is explored. First, tank trucks equipped with cylinder or elliptical cylinder tanks are modelled, and vehicle dynamics is analyzed. This dynamic model is used to provide I/O data in the controlled system. Next, the control objective of tank vehicle rollover stabilization is analyzed and the controlled variable is selected. Subsequently, differential braking and active front steering controller are designed by MFAC algorithm. Finally, the effectiveness of the designed controllers is verified by simulation, and difference between the controllers is analyzed. The controller designed by MFAC algorithm is proven to be adaptive to vehicle loading and driving states. The controlled system has great robustness.
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Smith, Anne E., David Cohan i Frank Selker. "A MODEL FOR MANAGING UNDERGROUND STORAGE TANKS". International Oil Spill Conference Proceedings 1987, nr 1 (1.04.1987): 599–604. http://dx.doi.org/10.7901/2169-3358-1987-1-599.
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ABSTRACT The potential costs of underground tank leaks provide companies with a solid incentive to take action to reduce leak risks. However, a cost-effective risk management strategy is difficult to identify when faced with the uncertainties in the occurrence, nature, and timing of costly incidents. A decision support model based on the techniques of decision analysis has been developed to help managers choose the best course of action. The model works by balancing the known costs of preventive and mitigating actions with the uncertain costs of tank leaks. The model uses tank- and site-specific data to help determine how much testing or monitoring to do at each tank site, when to replace tanks, what to do in the future contingent on monitoring results, and what new tank system to install. For each strategy, the model assesses detailed outcomes such as the expected life-cycle cost of the tank system, the expected time for replacing the system, the likelihood of a leak, and the expected costs of leaks. Input data include the reliability of the tank type, its age and its previous testing results, the vulnerability of resources near the tank, and the cost and accuracy of tank-testing technologies. The underground tank management model can be valuable to tank managers. Through sensitivity analysis, it can identify those aspects of the problem that critically determine sound management rules, and the areas for further data gathering that would be most fruitful for decision making. By looking at detailed results, one can investigate the implications of each strategy for different management goals. The model helps one sound out one's own management intuition, and leads to new insights on good management strategies. Initial model results have led to important insights. Leak costs are often a significant fraction of total life-cycle costs. The optimal management policy is thus quite sensitive to the characteristics of the tank site and the type of tank. Hence, a single management strategy applied to all types of tanks and sites may be detrimental to the tank owner's overall costs.
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Serdukov, V. I., N. A. Serdyukova i S. I. Shishkina. "Mathematical Single-Player Computer Game Model to Reproduce Duel Fight of Tanks". Mathematics and Mathematical Modeling, nr 3 (20.09.2020): 29–42. http://dx.doi.org/10.24108/mathm.0320.0000225.
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In improving computer games, which reproduce a battle of tanks, two tasks can be distinguished: increasing a collection of game tools to represent virtual prototypes of real tank models and ensuring a realistic game. To solve these problems, a tool is necessary that allows us to compare gaming capabilities of virtual tank brands with combat capabilities of their real prototypes. A mathematical model of a computer game that reproduces a duel battle of tanks can be used as the tool. The specified model satisfies the following requirements: the sequence of operations reproduced in the model is in line with the sequence of operations implemented by the player in the course of the game; the maximum amount of ammunition that a tank can use in a model must correspond to the amount of tank ammunition. The duel lasts until one of the tanks is hit, or until all the gunshots available to hit the enemy are expended. It is necessary to find the probabilities of possible outcomes of a duel battle, the mathematical expectation of its duration, the mathematical expectation of the ammunition consumption of each side.The solution to the problem is obtained by constructing a mathematical model according to the scheme of Markov random process with discrete states and continuous time. It is implemented as a program for a model of a duel battle of tanks and can be used when developing a computer game of the genre of tank simulators to assess the gaming capabilities of the virtual tanks in a duel battle from the data on the amount of their ammunition and on the intensity of the game process transition from one state to another; for selecting the intensity values of the game process transition from one state to another, based on the data on the estimated game capabilities of virtual tanks in a duel battle. Thus, game participants can use this model to conduct their own research. Developers of computer games can use it for setting up the game and setting such intensity values of the game process transition from one state to another, at which the gaming capabilities of virtual tanks will correspond to the combat capabilities of their real prototypes on the battlefield.
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Paulick, Nick, i Tom Rogers. "Section XII Transport Tank Code Preview—Cargo Tanks". Journal of Pressure Vessel Technology 128, nr 4 (2.01.2006): 665–66. http://dx.doi.org/10.1115/1.2349581.
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ASME Section XII Transport Tank Code will have an impact on the regulations related to the construction and continued service of highway cargo tanks used in the transportation of dangerous goods. Modal Appendix 1 of this code specifically addresses these transport tanks, and is intended to replace a large portion of the DOT regulations currently governing how they are built and serviced. This paper presents a preview of Modal Appendix 1, one of the mandatory appendices related to cargo tanks, and how these changes will affect manufacturers and repair shops.
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Liu, Jing, Zi Li Li i Zhi Shuan Cao. "Computational Simulation of Corrosion Perforation in the Oil-Tank Bottom with Cellular Automata". Advanced Materials Research 399-401 (listopad 2011): 1755–62. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.1755.
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Corrosion perforation in the oil-tank bottom is one of the most damaging mechanisms in oil-tanks. This paper presents a two-dimentional cellular automata model which simulates the corrosion perforation in the oil-tank bottom. According to the mechanism of metal corrosion in the oil-tank bottom, the CA model which simulates the electrochemical reactions and diffusion steps of pitting corrosion is proposed. With a series of simulation, the results show that CA is a powerful approach to model corrosion perforation in the oil-tank bottom, which could be of practical importance in predicting the security of oil-tanks.
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Youssef, Khaled S., Dean T. Mook, Ali H. Nayfeh i Saad A. Ragab. "Roll Stabilization by Passive Anti-Roll Tanks Using an Improved Model of the Tank-Liquid Motion". Journal of Vibration and Control 9, nr 7 (lipiec 2003): 839–62. http://dx.doi.org/10.1177/1077546303009007006.
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Roll motion is an undesirable feature of the behavior of a ship in rough seas, and so it is natural to consider ways of reducing it. The most common devices for increasing roll damping are bilge keels. However, the effectiveness of keels is limited, and anti-roll tanks and fins are used when more control is required. Moreover, unlike keels, anti-roll tanks can be used when the ship is not underway. Our objective is to develop design procedures for passive tanks for roll reduction in rough seas. To this end, we develop an improved model of the passive tank-liquid motion in this paper. This tank consists of U-shaped tubes placed side by side along the length of the ship. The equations of six-degrees-of-motion (6DOF) that govern the tank-liquid are coupled with those that govern the 6DOF motion of the ship, and all of the equations are integrated simultaneously in the time domain using the Large Amplitude Motion Program (“LAMP”). LAMP is a three-dimensional time-domain simulation of the motion of ships in waves. The unstabilized and stabilized roll motions of a S60-70 ship with forward speed and beam waves have been analyzed. For high-amplitude waves, the variation of the roll angle with the encounter-wave frequency exhibits typical nonlinear phenomena: a shift in the resonance frequency, multi-valued responses, and jumps. The performance of passive tanks on a S60-70 ship with forward speed is investigated in an irregular sea with different encounter-wave directions. It is found that passive anti-roll tanks tuned in the nonlinear range are very effective in reducing the roll motion. The effect of the tank mass and distribution of tank tubes on the performance of the tank system is studied. Also, it is found that passive anti-roll tanks are very effective in reducing the roll motion in sea state five of a ship whose pitch frequency is nearly twice its roll frequency.
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Giustolisi, Orazio, Luigi Berardi i Daniele Laucelli. "Generalizing WDN simulation models to variable tank levels". Journal of Hydroinformatics 14, nr 3 (29.11.2011): 562–73. http://dx.doi.org/10.2166/hydro.2011.224.
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In water distribution network (WDN) steady-state modelling, tanks and reservoirs are modelled as nodes with known heads. As a result, the tank levels are upgraded after every steady-state simulation (snapshot) using external mass balance equations in extended period simulation (EPS). This approach can give rise to numerical instabilities, especially when tanks are in close proximity. In order to obtain a stable EPS model, an unsteady formulation of the WDN model has recently introduced. This work presents an extension of the steady-state WDN model, both for demand-driven and pressure-driven analyses, allowing the direct prediction of head variation of tank nodes with respect to an initial state. Head variations at those nodes are introduced as internal unknowns in the model, the variation of tank levels can be analyzed in the single steady-state simulation and EPS can be performed as a sequence of simulations without the need for external mass balances. The extension of mass balance at tank nodes allows the analysis of some technically relevant demand components. Furthermore, inlet and outlet head losses at tank nodes are introduced and large cross-sectional tank areas are allowed by the model and reservoirs become a special case of tanks. The solution algorithm is the generalized-global gradient algorithm (G-GGA), although the proposed WDN model generalization is universal.
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Chen, Zengshun, Zhengang Xu, Lingxiao Teng, Jun Fu, Tao Xu i Zhihang Zhao. "Experimental and Numerical Investigation for Seismic Performance of a Large-Scale LNG Storage Tank Structure Model". Applied Sciences 12, nr 17 (23.08.2022): 8390. http://dx.doi.org/10.3390/app12178390.
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As special equipment for storing energy, the safety performance of liquified natural gas (LNG) storage tanks under earthquake action is extremely important. To study the dynamic characteristics of the large-scale LNG storage tank structure and the dynamic response under earthquake action, the shaking table test and numerical simulation analysis of the LNG storage tank structure model are carried out. The results of the shaking table test demonstrate that the natural vibration frequency of the tank model is significantly reduced after the isolation measures are taken. The acceleration response of the seismic storage tank increases approximately linearly along the direction of height, and the seismic isolation bearing has a significant seismic isolation effect on the acceleration of the storage tank. The numerical simulation results show that the seismic responses and their spectral characteristic curves of the numerical model and the shaking table test are the same, which verifies the feasibility and rationality of the numerical model. After seismic isolation measures are taken, the seismic responses of large-scale LNG storage tanks, such as base shear force, overturning bending moment and acceleration, are reduced to varying degrees, but the displacement of the storage tank increases to some extent. When carrying out the seismic isolation design of LNG storage tanks, it is necessary to focus on the displacement of the storage tank to prevent damage of the auxiliary pipeline led by excessive displacement.
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Kalantari, Afshin, Mohammad Reza Nikoomanesh i Mohammad Ali Goudarzi. "Applicability of Mass-Spring Models for Seismically Isolated Liquid Storage Tanks". Journal of Earthquake and Tsunami 13, nr 01 (luty 2019): 1950002. http://dx.doi.org/10.1142/s1793431119500027.
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Employing base isolation technique for reduction of seismic response of liquid storage tanks has been proved to be quite effective. The main purpose of this paper is to quantitatively clarify, the contribution of convective and impulsive parts of the contained liquid in seismic behavior of an isolated liquid tank. Moreover, the accuracy of the simplified model which is generally used for the prediction of seismic behavior of conventional tanks is examined for isolated liquid tanks. For these purposes, the seismic response of the isolated cylindrical liquid storage tanks is considered using both the exact finite element model and simplified mass-spring model. The fluid–structure interaction is considered in finite element model. The comparison of the results obtained from two models shows that unlike conventionally constructed tanks, the contribution of convective mass cannot be neglected for seismically isolated tanks. Moreover, the accuracy of the simplified model for evaluating the main design parameters including base shear, global overturning moment, and sloshing height is examined for various tank dimensions and earthquake ground motions. The difference between the base shear and overturning moment results in the FE model and the simplified model of an isolated tank limited to 10%. It approves that the simplified mechanical models can be used with confidence for evaluating the seismic design parameters of various isolated tanks. However, the free surface displacement cannot be accurately predicted by simplified models, especially for medium and broad tanks.
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Shrimali, M. K., i R. S. Jangid. "Dynamic Analysis of Liquid Storage Tanks with Sliding Systems". Advances in Structural Engineering 6, nr 2 (maj 2003): 145–58. http://dx.doi.org/10.1260/136943303769013237.
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Dynamic response of liquid storage tanks isolated by the sliding systems is investigated under real earthquake ground motion. The frictional force of sliding systems is modelled by conventional and hysteretic models. The continuous liquid mass is lumped as convective mass, impulsive mass and rigid mass. The corresponding stiffness associated with these lumped masses is worked out depending upon the properties of the tank wall and liquid mass. The governing equations of motion of the tank with sliding system are derived and solved by Newmark's step-by-step method with iterations. The frictional force mobilized at the interface of the sliding system is assumed to be velocity dependent. For comparative study, the seismic response of isolated liquid storage tank obtained by the conventional model is compared with the corresponding response obtained by the hysteretic model. In order to measure the effectiveness of isolation system, the seismic response of isolated tank is compared with that of the non-isolated tank. A parametric study is also conducted to study the effects of aspect ratio of tank on the effectiveness of seismic isolation of liquid storage tanks. It is found that the sliding systems are quite effective in reducing the earthquake response of liquid storage tanks. In addition, the conventional and the hysteretic model of the sliding system predict the same seismic response of liquid storage tanks. However, the conventional model is relatively more computationally efficient as compared to the hysteretic model.
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Stamou, A. I., M. Latsa i D. Assimacopoulos. "Design of two-storey final settling tanks using mathematical models". Journal of Hydroinformatics 2, nr 4 (1.10.2000): 235–45. http://dx.doi.org/10.2166/hydro.2000.0021.
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A mathematical model is applied to the design of two-storey final settling tanks. Computations show that the flow and suspended solids (SS) concentration fields for the upper and bottom tanks are similar. The flow field has the ‘two-layer’ structure, observed in real and laboratory settling tanks, consisting of a bottom current and a free surface return current with approximately equal heights. The SS concentration field is governed by the flow field (and vice versa). The SS concentration profiles are uniform in the major part of the tanks. The hydraulic and SS removal efficiencies improve with decreasing flow rate. In both tanks the outlet SS concentrations are lower than the maximum permissible value (20 mg l−1), with the upper tank showing a better performance than the bottom tank.
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Sheng, Dong-Yuan, i Zongshu Zou. "Application of Tanks-in-Series Model to Characterize Non-Ideal Flow Regimes in Continuous Casting Tundish". Metals 11, nr 2 (23.01.2021): 208. http://dx.doi.org/10.3390/met11020208.
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This study describes a new tanks-in-series model for analyzing non-ideal flow regimes in a single-strand tundish. The tundish was divided into two interconnected tanks, namely an inlet tank and an outlet tank. A water model experiment was carried out to separately measure the residence-time distribution (RTD) of the two tanks. Drift beads were adopted in the water model experiment to simulate the non-metallic inclusions in molten steel. Dead volume fraction was evaluated by analyzing measured RTD curves. The ratio between mixed flow volume and plug flow volume was proposed as a new criterion to evaluate the inclusion removal. In the inlet tank, a higher mixed flow fraction was preferred to effectively release turbulent kinetic energy and enhance inclusion collision growth. In the outlet tank, a higher plug flow fraction was preferred to facilitate inclusion removal by flotation. The optimal positions of the weir were recommended based on the RTD analysis and the inclusion removal from the results of water model experiments. A theoretical equation was derived based on the tanks-in-series model, providing a good fitting function to analyze the experimental data. The confirmation test was performed by applying computational fluid dynamics simulations of liquid steel flow in the real tundish.
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Saha, Sandip Kumar, Vasant A. Matsagar i Arvind K. Jain. "Earthquake Response of Base-Isolated Liquid Storage Tanks for Different Isolator Models". Journal of Earthquake and Tsunami 08, nr 05 (grudzień 2014): 1450013. http://dx.doi.org/10.1142/s1793431114500134.
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The effect of different isolator parameters on earthquake response of base-isolated liquid storage tanks is investigated herein. Mechanical analog, with three lumped masses, is used to model ground supported base-isolated liquid storage tank, and analyzed for recorded earthquake ground accelerations. The nonlinear force–deformation behavior of the isolator is mathematically modeled in two different ways, represented by (a) equivalent linear elastic-viscous and (b) bi-linear hysteretic behaviors. The equations of motion for the base-isolated tank are derived and solved in the incremental form using Newmark's step-by-step method of integration. Two different configurations of liquid storage tank (i.e. broad and slender) are considered to show the effect of the equivalent linear and bi-linear modeling of the isolator on the important earthquake response quantities. Effect of nonlinear hysteretic modeling of the isolator on peak response of the base-isolated liquid storage tanks is also investigated. The effect on earthquake response of the base-isolated liquid storage tank is studied for different parameters of the isolator for a range of slenderness ratio of the tank. The parameters considered include the characteristic strength of the isolator, isolation time period, isolator yield displacement etc. Significant difference is observed in the earthquake response of the base-isolated liquid storage tanks owing to the equivalent linear and bi-linear modeling approaches of the isolator. However, for bi-linear and nonlinear hysteretic modeling of the isolator, difference between the peak earthquake response of base-isolated liquid storage tanks are insignificant. The earthquake response of base-isolated liquid storage tanks is significantly influenced by the variation in the isolator parameters and slenderness ratio of the tank.
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Love, J. S., i M. J. Tait. "Linearized sloshing model for 2D tuned liquid dampers with modified bottom geometries". Canadian Journal of Civil Engineering 41, nr 2 (luty 2014): 106–17. http://dx.doi.org/10.1139/cjce-2013-0106.
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This study presents a new model for predicting the response of a two-dimensional tuned liquid damper (TLD) tank with a variable fluid depth. A simple finite element method is presented, which is used to calculate the sloshing mode shapes. From the mode shapes, the equivalent mechanical properties of the sloshing fluid are estimated. Three tanks (flat-bottom, triangular-bottom, and circular-bottom), which have closed-form expressions for their equivalent mechanical properties are used to evaluate the model. The proposed model is in agreement with the closed-form expressions. Subsequently, a parametric study is conducted on tanks with a chamfered-bottom, boxed-bottom, and ramped-bottom to assess how their properties change as the shape of the tank bottom is altered. The model provides TLD designers with greater flexibility when selecting a tank shape. Moreover, the model could be used to optimize the shape of a TLD tank to maximize its performance for a given liquid mass, allowing construction cost savings to be realized.
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Shi, Cai Xia, i Wei Min Yang. "Analysis of Modal and Seismic Property of Oil Storage Tanks". Applied Mechanics and Materials 527 (luty 2014): 95–99. http://dx.doi.org/10.4028/www.scientific.net/amm.527.95.
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In the engineering background of 1000 cubic meters of anchored tank, the large-scale finite element software ANSYS was used to analysis of modal and transient of oil storage tanks. Completed oil tank model and carried on the modal analysis and then vibration characteristics were gained. On this basis, considering the earthquake excitation, analyzes dynamic response of the anchored tank under seismic load. Then gained the oil tank overall structure of displacement, equivalent stress, axial and circumferential stress. From images can be analyzed that the main vibration mode is multiple circumferential wave, the stress of upper tank and its seams is the largest under earthquake loading and easy to be damaged, strengthen circle should be set up. Through the simulation analysis provided powerful basis for seismic design of the vertical storage tank.
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Jendželovský, Norbert, i Lenka Uhlířová. "Rectangular tank under the seismic load". MATEC Web of Conferences 313 (2020): 00022. http://dx.doi.org/10.1051/matecconf/202031300022.
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Tanks have been currently used for the storage of various substances, in particular as drinking water storage tanks and for storage of various technical fluids. Rectangular tanks have advantages over cylindrical tanks, such as: lower sensitivity to unilateral loads and better use of space when used in a system of tanks. The rectangular tank analyzed in this article is filled with water. During the dynamic analysis of the tank, it was loaded by an accelerogram of a natural earthquake. In the calculation, the method of direct integration over time was used, considering damping. From the accelerogram a response spectrum was generated and applied as an additional loading of the tank. The static model of the tank was created in the ANSYS program, which works on the basis of the finite element method (FEM).
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Hernandez-Lopez, R. D., V. G. Tzatchkov, A. Martin-Dominguez i V. H. Alcocer-Yamanaka. "Study of hydraulics and mixing in roof tanks used in intermittent water supply". Journal of Water, Sanitation and Hygiene for Development 6, nr 4 (4.10.2016): 547–54. http://dx.doi.org/10.2166/washdev.2016.147.
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Roof tanks are common in low and middle income countries, due to the intermittent water supply. Their hydraulic and water mixing behaviour has not been studied. This paper presents the results of a study on mixing and water demand in roof tanks, based on physical and numerical models. Tracer tests were carried out on a real scale transparent wall laboratory model of a roof tank, and a three-parameter residence time distribution model was applied, showing that the model that best describes mixing in roof water tanks is the one with a completely stirred flow reactor with a small portion of bypassing. This result was confirmed by computational fluid dynamic simulations and visual observation. The instantaneous water flow derived from activating typical home water-using fixtures was measured at the pipe feeding the tank, the pipe exiting the tank, and without a roof tank. Stochastic water demand patterns were generated with the measured data and used in the numerical model of a small distribution network. Based on this model it was found that water demand and pipe flow behave differently in continuous and intermittent water supply networks. The instantaneous flow rate withdrawn from the water distribution network pipes is lower in systems with roof tanks.
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Sivý, Martin, i Miloš Musil. "Seismic Resistance of Storage Tanks Containing Liquid in Accordance with Principles of Eurocode 8 Standard". Strojnícky casopis – Journal of Mechanical Engineering 66, nr 2 (1.11.2016): 79–88. http://dx.doi.org/10.1515/scjme-2016-0021.
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Abstract Large capacity tanks storing various liquids are important components in distribution and transmission systems. During operation tanks can be subjected to different types of loading. Therefore, maximum attention must be paid to the tank design to capture all possible causes and forms of failures. The article deals with the procedure for seismic resistance of liquid storage tanks which are in accordance with the principles of Eurocode 8 standard. The seismic analysis is performed on flexible (steel) circular vertical ground-supported model of tank containing liquid (water). The main aim is to determine basic seismic characteristics, distributions of hydrodynamic pressure, dynamic properties and response of investigated tank-liquid system subjected to earthquake excitation (El Centro). Seismic analysis and results comparison are carried out on mechanical spring-mass model (Eurocode 8) and finite element model (ANSYS).
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Campisano, Alberto, i Carlo Modica. "Appropriate resolution timescale to evaluate water saving and retention potential of rainwater harvesting for toilet flushing in single houses". Journal of Hydroinformatics 17, nr 3 (3.01.2015): 331–46. http://dx.doi.org/10.2166/hydro.2015.022.
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The main objective of the paper is to identify the appropriate temporal scale for modeling the behavior of rainwater harvesting tanks in relation to the purpose they are built for, i.e., water saving, stormwater retention potential, etc. A tank water balance model coupled with a specific procedure to determine long-term series of rainfall (tank inflow) and toilet flushes (tank outflow) at different daily and sub-daily resolution timescales was developed. The model was applied to a household case study for which detailed water demand data are available from measurements. Simulations show that the daily scale may be reliably chosen to evaluate the tank water saving efficiency. In contrast, sub-daily resolutions (at least the hourly time step) are needed for the evaluation of the tank retention efficiency to limit inaccuracies, especially for small tanks and for high values of the water demand. Moreover, preliminary results at the 5 min time step show that rainwater tanks can help in reducing the rainfall intensity peak, basically depending on the tank storage and on the rainfall event characteristics.
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Chen, Geng, Jia Qu i Chun Yu Tian. "Numerical Analysis of Ring Beam Effect on the Modal of LNG Storage Tank". Applied Mechanics and Materials 638-640 (wrzesień 2014): 172–77. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.172.
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LNG storage tank is an important department in the gas receiving station. LNG in the tank is flammable and explosive medium, once the tank damaged, disasters may be happened. So researching the dynamic response analysis is very necessary. In this paper, modal analysis of LNG outside tank were performed by ANSYS Workbench, the first six orders of mode shapes and their frequencies of LNG outside tank were concluded. Contrast vibration mode and natural frequency of the LNG storage tanks with ring beam and no ring beam, the influence of ring beam of LNG tank mode has been discussed. Conduct a series experiment by change the parameters of the ring beam, Parameters for ring beam effect on the inherent frequency and vibration mode of LNG outside tank has been researched. This research has provided the provided the reliable basis for the safety using of tanks and has built the base of the further dynamic response analysis.
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Abdulwahid, Maan M., i Noraldeen B. Mohammed Wasel. "Design and Implementation of Water Level Tank Model by using SCADA System". Informatica : Journal of Applied Machines Electrical Electronics Computer Science and Communication Systems 01, nr 01 (1.12.2020): 63–69. http://dx.doi.org/10.47812/ijamecs2010109.
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Recently, SCADA system has been widely deployed in several stations and performing different purposes by connecting it with different hardware components and terminals. As a result, in this paper, it has been designed and proposed a model for water tank level-based detection for the scenarios of station that contains several tanks. The proposed model has shown a significant in performance and enhance the response of the tank management with both cases of tank filling and discharging.
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Chaudhari, Mr Rohit Kiran. "Non-Linear Time History Analysis of an Elevated Water Tank". International Journal for Research in Applied Science and Engineering Technology 9, nr VI (30.06.2021): 4327–34. http://dx.doi.org/10.22214/ijraset.2021.35939.
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It was discovered that reinforced concrete elevated water tanks with frame staging outperformed reinforced concrete elevated water tanks with shaft staging in terms of seismic resistance. These can be due to the frame staging's seismic energy absorption capability. As a result, the primary goal of this research is to better understand the seismic behavior and performance characteristics of elevated water tanks with frame staging. Furthermore, when compared to other shapes, circular tanks have the smallest surface area for a given tank size. As a result, the amount of material needed for a circular water tank is less than for other shapes. As a result, a circular water tank was chosen, and seismic analysis of elevated RC circular water tanks was carried out according to IITK-GSDMA guidelines, with the behavior of the water tank analysed for various parameters such as zone factor, soil condition, and different staging heights. SAP 2000 was used to determine the structure's modal characteristics (mode shapes and modal participation mass ratio).
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Kim, Youngjin, i Mooyoung Han. "Rainwater storage tank as a remedy for a local urban flood control". Water Supply 8, nr 1 (1.04.2008): 31–36. http://dx.doi.org/10.2166/ws.2008.029.
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Surcharge runoff over the capacity of drainage pipes is one of main flood breaking factors in urban area. Change into larger pipes is costly and time consuming solution. Rainwater tanks can be a sustainable solution for the control of heavy runoff. The Rainfall-Storage-Drain(RSD) model is developed for the design of rainwater tanks of flood control. Design rainfall of Huff's distribution and runoff analysis on building rooftop makes inflow curves into the tanks. Through a water balance equation, tank volume versus peak flow curves can determine the minimum tank volume needed for controlled peak flow value of a design period. The case study in Seoul City shows a tank of 29 L/m2 can control the runoff of 30-years with the drainage pipes of 10-years design period. The RSD model can give simple and easy curves to understand for tank capacity determination in a local flood condition.
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Lara, Pedro, i Masato Kobiyama. "Proposta de Modelo Conceitual: PM Tank Model". Revista Brasileira de Recursos Hídricos 17, nr 3 (2012): 149–61. http://dx.doi.org/10.21168/rbrh.v17n3.p149-161.
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Miller, T., i A. M. Birk. "A Re-Examination of Propane Tank Tub Rockets Including Field Trial Results". Journal of Pressure Vessel Technology 119, nr 3 (1.08.1997): 356–64. http://dx.doi.org/10.1115/1.2842316.
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When a tank containing a pressure-liquefied gas fails, one mode of failure involves the tank being propelled large distances by the released two-phase material. This mode of failure is called a tub rocket and it can pose a severe hazard to the public because of its unpredictability. Field tests were recently conducted to study the effect of explosive devices on propane tanks. The tests included tanks of various sizes up to 2000 L (500 gal).In most cases, the tests resulted in punctured tanks with transient two-phase jet releases. In some cases, the jet releases were sufficient to propel the tanks over considerable distances. In a small number of tests involving 470-L tanks, the explosive device resulted in the clean removal of a tank end, and this resulted in near-ideal launches of tub rockets. In one case, the rocket was launched vertically, and in another, the rocket was launched near 45 deg elevation angle giving a tub range of 370 m. In other cases, the explosive devices resulted in punctures, and in some of these, the resulting two-phase jet propelled the tanks over considerable distance. These examples gave a good opportunity to re-examine tub rocket models for tanks containing liquefied gases. This paper describes a theoretical model involving two-phase critical flow propulsion of cylindrical tanks. Three different critical flow models are compared, including the homogeneous equilibrium model (HEM), the homogeneous frozen model (HFM), and the Henry-Fauske model (HFK). Range predictions are compared with existing data and a model previously developed. Model predictions are calibrated to the field trial results described in the foregoing and then used to predict realistic ranges for various sizes of storage and transport tanks.