1,128 research outputs found

    Material Evaluation: Self Damping Wire SD/ACSR Conductor Failures

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    Following numerous 954 ACSR SD Wire failures from 2010 to 2012, Nebraska Public Power District (NPPD) implemented an inspection program to determine the extent of condition for this type of widely used conductor. NPPD transmission system includes over 2000 miles of this particular conductor. Transmission line splices are installed every 15-20 spans, with failures being located in a span containing a splice. NPPD worked with Kinectrics to complete electromagnetic field inspections for three days in 2013, with retesting performed in 2015. Throughout this inspection of 54 spans of conductor, 36 were found to have deterioration and corrosion. Over 80% of the corrosion noted in the report was found on a conductor span containing a splice; only 45% of the spans tested contain a splice. All of the failures occurred in spans where a compression sleeve or compression dead-end was present. In all cases, only the steel core broke internal to trapezoidal aluminum wire layers. The results of the inspection indicated that there is a notable amount corrosion located in the few hundred feet at the center of the span. Removal of spans testing “marginal” occurred in April 2015, along with the physical evaluation of the conductor validating the results of the electromagnetic inspection tool. None of the conductors were rated as poor, which would indicate no imminent failures exist. Since none of these localized areas were in poor condition, it could be several years before more frequent findings of broken wire and related problems are observed. Advisor: Jeffrey E. Shiel

    Material Evaluation: Self Damping Wire SD/ACSR Conductor Failures

    Get PDF
    Following numerous 954 ACSR SD Wire failures from 2010 to 2012, Nebraska Public Power District (NPPD) implemented an inspection program to determine the extent of condition for this type of widely used conductor. NPPD transmission system includes over 2000 miles of this particular conductor. Transmission line splices are installed every 15-20 spans, with failures being located in a span containing a splice. NPPD worked with Kinectrics to complete electromagnetic field inspections for three days in 2013, with retesting performed in 2015. Throughout this inspection of 54 spans of conductor, 36 were found to have deterioration and corrosion. Over 80% of the corrosion noted in the report was found on a conductor span containing a splice; only 45% of the spans tested contain a splice. All of the failures occurred in spans where a compression sleeve or compression dead-end was present. In all cases, only the steel core broke internal to trapezoidal aluminum wire layers. The results of the inspection indicated that there is a notable amount corrosion located in the few hundred feet at the center of the span. Removal of spans testing “marginal” occurred in April 2015, along with the physical evaluation of the conductor validating the results of the electromagnetic inspection tool. None of the conductors were rated as poor, which would indicate no imminent failures exist. Since none of these localized areas were in poor condition, it could be several years before more frequent findings of broken wire and related problems are observed. Advisor: Jeffrey E. Shiel

    Material Evaluation: Self Damping Wire SD/ACSR Conductor Failures

    Get PDF
    Following numerous 954 ACSR SD Wire failures from 2010 to 2012, Nebraska Public Power District (NPPD) implemented an inspection program to determine the extent of condition for this type of widely used conductor. NPPD transmission system includes over 2000 miles of this particular conductor. Transmission line splices are installed every 15-20 spans, with failures being located in a span containing a splice. NPPD worked with Kinectrics to complete electromagnetic field inspections for three days in 2013, with retesting performed in 2015. Throughout this inspection of 54 spans of conductor, 36 were found to have deterioration and corrosion. Over 80% of the corrosion noted in the report was found on a conductor span containing a splice; only 45% of the spans tested contain a splice. All of the failures occurred in spans where a compression sleeve or compression dead-end was present. In all cases, only the steel core broke internal to trapezoidal aluminum wire layers. The results of the inspection indicated that there is a notable amount corrosion located in the few hundred feet at the center of the span. Removal of spans testing “marginal” occurred in April 2015, along with the physical evaluation of the conductor validating the results of the electromagnetic inspection tool. None of the conductors were rated as poor, which would indicate no imminent failures exist. Since none of these localized areas were in poor condition, it could be several years before more frequent findings of broken wire and related problems are observed. Advisor: Jeffrey E. Shiel

    Experiments reveal enrichment of 11B in granitic melt resulting from tourmaline crystallisation

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    Tourmaline is the most common boron-rich mineral in magmatic systems. In this study, we determined experimentally the fractionation of boron isotopes between granitic melt and tourmaline for the first time. Our crystallisation experiments were performed using a boron-rich granitic glass (B2O3 ≈ 8 wt. %) at 660−800 °C, 300 MPa, and aH2O = 1, in which tourmaline occurs as the only boron-hosting mineral. Our experimental results at four different temperatures show a small and temperature-dependent boron isotope fractionation between granitic melt and tourmaline (Δ11Bmelt–Tur = þ0.90 ± 0.05 ‰ at 660 °C and þ0.23 ± 0.12 ‰ at 800 °C), and the temperature dependence can be defined as Δ11Bmelt–Tur = 4.51 × (1000/T [K]) − 3.94 (R2 = 0.96). Using these boron isotope fractionation factors, tourmaline can serve as a tracer to quantitatively interpret boron isotopic ratios in evolved magmatic systems. Our observation that 11B is enriched in granitic melt relative to tourmaline suggests that the δ11B of late-magmatic tourmaline should be higher than tourmaline that crystallised at an early stage, if B isotope fractionation is not affected by other processes, such as fluid loss. © 2022 The Authors

    Cardiotoxicity of mitoxantrone treatment in a german cohort of 639 multiple sclerosis patients

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    Background and Purpose: The aim of this study was to elucidate the role of therapy-related cardiotoxicity in multiple sclerosis (MS) patients treated with mitoxantrone and to identify potential predictors for individual risk assessment. Methods: Within a multicenter retrospective cohort design, cardiac side effects attributed to mitoxantrone were analyzed in 639 MS patients at 2 MS centers in Germany. Demographic, disease, treatment, and follow-up data were collected from hospital records. Patients regularly received cardiac monitoring during the treatment phase. Results: None of the patients developed symptomatic congestive heart failure. However, the frequency of patients experiencing cardiac dysfunction of milder forms after mitoxantrone therapy was 4.1% (26 patients) among all patients. Analyses of the risk for cardiotoxicity revealed that cumulative dose exposure was the only statistically relevant risk factor associated with cardiac dysfunction. Conclusions: The number of patients developing subclinical cardiac dysfunction below the maximum recommended cumulative dose is higher than was initially assumed. Interestingly, a subgroup of patients was identified who experienced cardiac dysfunction shortly after initiation of mitoxantrone and who received a low cumulative dose. Therefore, each administration of mitoxantrone should include monitoring of cardiac function to enhance the treatment safety for patients and to allow for early detection of any side effects, especially in potential high-risk subgroups (as determined genetically)

    Blockade of insulin-like growth factors increases efficacy of paclitaxel in metastatic breast cancer

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    Breast cancer remains the leading cause of cancer death in women owing to metastasis and the development of resistance to established therapies. Macrophages are the most abundant immune cells in the breast tumor microenvironment and can both inhibit and support cancer progression. Thus, gaining a better understanding of how macrophages support cancer could lead to the development of more effective therapies. In this study, we find that breast cancer-associated macrophages express high levels of insulin-like growth factors 1 and 2 (IGFs) and are the main source of IGFs within both primary and metastatic tumors. In total, 75% of breast cancer patients show activation of insulin/IGF-1 receptor signaling and this correlates with increased macrophage infiltration and advanced tumor stage. In patients with invasive breast cancer, activation of Insulin/IGF-1 receptors increased to 87%. Blocking IGF in combination with paclitaxel, a chemotherapeutic agent commonly used to treat breast cancer, showed a significant reduction in tumor cell proliferation and lung metastasis in pre-clinical breast cancer models compared to paclitaxel monotherapy. Our findings provide the rationale for further developing the combination of paclitaxel with IGF blockers for the treatment of invasive breast cancer, and Insulin/IGF1R activation and IGF+ stroma cells as potential biomarker candidates for further evaluation
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