Novel Approach towards Fuel Tank Heat Shield Design

2017 ◽  
Author(s):  
V N Bhasker ◽  
Abhinav Agarwal ◽  
Abhishek Sharma ◽  
Avisek Das ◽  
Nirajkumar Mishra
Keyword(s):  
Fuel Tank ◽  
Heat Shield ◽  
Novel Approach ◽  
Shield Design

Fuel Tank Heat Shield Design

1990 ◽  
Author(s):  
Colin Jordan ◽  
Dale Matkovich
Keyword(s):  
Fuel Tank ◽  
Heat Shield ◽  
Shield Design

Design of Heat Shield for Compressor Case of Industrial Gas Turbine to Meet Clearance Requirement

2020 ◽  
Author(s):  
Prashant Malavade ◽  
Santhana G. Babu ◽  
Luca Frosini ◽  
Simone Marchetti
Keyword(s):  
Gas Turbine ◽  
Low Cycle Fatigue ◽  
Operating Conditions ◽  
Heat Shield ◽  
Design Parameters ◽  
Cycle Fatigue ◽  
Excessive Heat ◽  
The Impact ◽  
Shield Design ◽  
Aerodynamic Losses

Abstract In Gas Turbine design key important role was to establish proper clearance between rotating and statoric parts during operating conditions which controls the performance, cooling flow requirements, part performance etc., These clearances must be optimized to meet product requirements. Too tight clearance at assembly condition causes excessive rubbing during starting or shutdown of gas turbine which could cause excessive heat generation and damage rotating and statoric parts. In some case, rubbing can cause tip liberations and damages to flow path causing aero dynamic losses. Similarly, if clearance is large at assembly condition causes aerodynamic losses. In this paper describes the experience of Baker Hughes, in design of compressor case wherein different design options in casing design with and without considering external features / components are considered to have adequate clearance between rotating and statoric parts. It also describes the Heat shield design iterations which was provided on a compressor case to establish proper thermal response during transient operating conditions. This helps in providing adequate clearance without causing excessive rubs or too large clearance avoiding aerodynamic losses. During development of heat shield design, challenges encountered considering clearance, manufacturing aspects, assembly feasibility and part life capabilities like low cycle fatigue, high cycle fatigue requirements are discussed in the paper. Also heat shield was subjected to high thermal gradient due to temperature difference, this makes heat shield to have constrained growth. This restriction in growth provides huge stresses beyond the material limit causing it to fail before product requirement time period. To avoid constrained growth, this paper describes how the heat shield was connected to casing by different means are mentioned. It also describes the impact on frequency margin if there is not adequate fixity in heat shield design. Some of the design parameters like circumferential & axial ribs and intermittent stiffeners and its influence on stress by comparing against yield and on frequency margin with reference to potential driver are also discussed in this paper. It also incorporates the methods to control intersegment leakages and design features to avoid interface interference. Feasibility study of heat shield design was done using finite element modeling techniques using ANSYS tool and its best practices would also be dealt in this paper.

Ablative Heat Shield Design for Reentry Vehicle Using Numerical Analysis

2014 ◽  
Vol 598 ◽  
pp. 298-303
Author(s):  
Amir Mahdi Tahsini ◽  
Samaneh Tadayon Mousavi
Keyword(s):  
Heat Flux ◽  
Heat Shield ◽  
Interface Temperature ◽  
Final Thickness ◽  
Reentry Vehicle ◽  
Simulated Trajectory ◽  
Flux Profile ◽  
Heat Shields ◽  
Energy Equations ◽  
Shield Design

At this paper, the thermal behavior of ablative materials as heat shields for reentry vehicles is investigated numerically. A one-dimensional finite difference solver is developed to simulate governing mass and energy equations. Four ablative materials; AVCO 5026-HCG, Carbon-Phenolic, Nylon-Phenolic, and Silica-Phenolic; are considered as a heat shield material for a reentry capsule with the diameter 2.8 meter. A heat flux profile from a simulated trajectory of a reentry capsule is used for investigation the performance and essential thickness of these four ablative materials. The only restriction for this simulation is the ultimate temperature of the backup structure which is beneath the ablative heat shield. At all simulations, the final thickness is defined by reaching the interface temperature, the temperature of the border between the ablative heat shield and solid shell, to 80±0.5 degrees Celsius. In addition, the sensitivity analysis is carried out to investigate the effect of properties variations on Carbon-Phenolic’s thickness for this specific heat flux profile.

Copper-dependent ATP7B up-regulation drives the resistance of TMEM16A-overexpressing head-and-neck cancer models to platinum toxicity

2019 ◽  
Vol 476 (24) ◽  
pp. 3705-3719 ◽  
Author(s):  
Avani Vyas ◽  
Umamaheswar Duvvuri ◽  
Kirill Kiselyov
Keyword(s):  
Oxidative Stress ◽  
Head And Neck ◽  
Transcriptional Activation ◽  
Platinum Resistance ◽  
Mrna Levels ◽  
Strong Positive Correlation ◽  
Platinum Compounds ◽  
Copper Chelation ◽  
Novel Approach ◽  
Cancer Models

Platinum-containing drugs such as cisplatin and carboplatin are routinely used for the treatment of many solid tumors including squamous cell carcinoma of the head and neck (SCCHN). However, SCCHN resistance to platinum compounds is well documented. The resistance to platinum has been linked to the activity of divalent transporter ATP7B, which pumps platinum from the cytoplasm into lysosomes, decreasing its concentration in the cytoplasm. Several cancer models show increased expression of ATP7B; however, the reason for such an increase is not known. Here we show a strong positive correlation between mRNA levels of TMEM16A and ATP7B in human SCCHN tumors. TMEM16A overexpression and depletion in SCCHN cell lines caused parallel changes in the ATP7B mRNA levels. The ATP7B increase in TMEM16A-overexpressing cells was reversed by suppression of NADPH oxidase 2 (NOX2), by the antioxidant N-Acetyl-Cysteine (NAC) and by copper chelation using cuprizone and bathocuproine sulphonate (BCS). Pretreatment with either chelator significantly increased cisplatin's sensitivity, particularly in the context of TMEM16A overexpression. We propose that increased oxidative stress in TMEM16A-overexpressing cells liberates the chelated copper in the cytoplasm, leading to the transcriptional activation of ATP7B expression. This, in turn, decreases the efficacy of platinum compounds by promoting their vesicular sequestration. We think that such a new explanation of the mechanism of SCCHN tumors’ platinum resistance identifies novel approach to treating these tumors.

Collecting Words: A Clinical Example of a Morphology-Focused Orthographic Intervention

2020 ◽  
Vol 51 (3) ◽  
pp. 544-560 ◽  
Author(s):  
Kimberly A. Murphy ◽  
Emily A. Diehm
Keyword(s):  
Written Language ◽  
Morphological Knowledge ◽  
English Orthography ◽  
Word Level ◽  
Novel Approach ◽  
Language Pathology ◽  
The One ◽  
Critical Intervention ◽  
Reading And Spelling ◽  
Reading And Spelling Difficulties

Purpose Morphological interventions promote gains in morphological knowledge and in other oral and written language skills (e.g., phonological awareness, vocabulary, reading, and spelling), yet we have a limited understanding of critical intervention features. In this clinical focus article, we describe a relatively novel approach to teaching morphology that considers its role as the key organizing principle of English orthography. We also present a clinical example of such an intervention delivered during a summer camp at a university speech and hearing clinic. Method Graduate speech-language pathology students provided a 6-week morphology-focused orthographic intervention to children in first through fourth grade ( n = 10) who demonstrated word-level reading and spelling difficulties. The intervention focused children's attention on morphological families, teaching how morphology is interrelated with phonology and etymology in English orthography. Results Comparing pre- and posttest scores, children demonstrated improvement in reading and/or spelling abilities, with the largest gains observed in spelling affixes within polymorphemic words. Children and their caregivers reacted positively to the intervention. Therefore, data from the camp offer preliminary support for teaching morphology within the context of written words, and the intervention appears to be a feasible approach for simultaneously increasing morphological knowledge, reading, and spelling. Conclusion Children with word-level reading and spelling difficulties may benefit from a morphology-focused orthographic intervention, such as the one described here. Research on the approach is warranted, and clinicians are encouraged to explore its possible effectiveness in their practice. Supplemental Material https://doi.org/10.23641/asha.12290687

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