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Selection and Impact of an Aerofoil Leading Edge on Boundary Layer Transition

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Journal of Transportation Technologies 2022年第4期12卷 778-803页

作者： dinesh bhatia Devinder Kumar Yadav Guangjun Yang Jian Wang Henrik Hesse School of Aerospace Engineering University of Glasgow Glasgow Singapore School of Aerospace University of Nottingham Ningbo China Ningbo China School of Aeronautics Northwestern Polytechnical University Xi’an China Faculty of Science Engineering and Computing Kingston University London UK

The choice of leading-edge aspect ratio (AR) plays a crucial role when planning boundary layer wind tunnel tests on a flat plate. Poor selection of the leading-edge profile hampers effectiveness of the experiment and increases testing costs associated with interchanging of leading edges to attain accurate results. Thus, the appropriate selection of the leading edge is a very crucial part of the wind tunnel experiment process. It is argued that the curvature of the leading edge and thus the AR is of paramount importance to achieve accurate results from the wind tunnel testing. In this project, seven different elliptical leading edges were tested, and their performance was compared with an ideal leading edge with zero thickness. Experiments and computation have been done for leading edges ranging from AR6 to AR20. Results were evaluated for boundary layer transition onset location, and it was found that AR20 has the least influence on the flow structure when compared to the ideal leading edge. A study of the flow structure at the stagnation point indicates an increase in adverse pressure gradient with an increase in the AR but also shows a decrease in the size of the stagnation region. The presence of a higher AR leading edge reduces the turbulent spot production rate, which is one of the primary causes of boundary layer transition. This paper presents a correlation that enables aerodynamicists to quantify the impact of the leading-edge AR on transition. A typical case is also presented to compare the relative performance of a wedge and the higher AR leading edge, which provides a choice between an elliptical or a wedge-shaped leading edge.

关键词： Boundary Layer Transition Leading Edge Aspect Ratio Curvature Flow Structure Adverse Pressure Gradient

Contrastive Analysis of Distractions to Pilot Caused by Various Flight Instrument Displays

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Journal of Transportation Technologies 2022年第2期12卷 209-227页

作者： Devinder Kumar Yadav Yingxue Zhao Chunyi Gao Yufei Wang Tianzuo Dong dinesh bhatia University of Nottingham Ningbo Ningbo China University of Glasgow Singapore Singapore

Automation of aircraft instrument displays enhances flight safety, but it also increases complexity and pilot workload. Executing changes in flight plan, navigation or communication during flight using flight instrument switches often increases pilots’ workload and this may also cause distraction that adds potential risks to flight safety. This study compares the conventional avionics panel and touchscreen avionic panel to find out the least distractive panel for the pilots. Thirty simulated flights using four different pilots were carried out;and aircraft speed, altitude and heading parameters using both avionics systems were observed to study the operational efficiency and pilot distraction resulted from each of the avionic systems. The distraction was examined by a parameter analysis based on the Mean Squared Error (MSE) mathematical model and visually by recording videos of each simulated flight. The results indicate that the touchscreen system is more efficient and less erroneous for the aircraft in maintaining the parameters as compared with the conventional system. There is also a clear relationship between task completion time and disruption level on the parameters control.

关键词： Aviation Touchscreen Safety Conventional Cockpit Simulate Flight

Spinal cord compression secondary to bone metastases from hepatocellular carcinoma

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World Journal of Gastroenterology 2006年第32期12卷 5247-5252页

作者： dinesh Chandra Doval Komal bhatia Ashok Kumar Vaid Keechelat Pavithran Jai Bhagwan Sharma Digant Hazarika Amarnath Jena Department of Medical Oncology Rajiv Gandhi Cancer Institute and Research Centre Rohini Sector- 5Delhi-110085India Department of Pathology Rajiv Gandhi Cancer Institute and Research Centre Rohini Sector- 5Delhi-110085India Department of Nuclear Medicine Rajiv Gandhi Cancer Institute and Research Centre Rohini Sector- 5Delhi-110085India

Bone metastases are rare in primary hepatocellular carcinoma （HCC）. Spinal cord compression （SCC） due to bone metastases occur commonly in patients with lung and breast carcinomas, and metastatic HCC is an unusual cause of SCC. Spinal cord compression is an oncologic emergency and treatment delays can lead to irreversible consequences. Thus, the awareness that SCC could be a potential complication of bone metastases due to HCC is of significance in initiation of early treatment that can improve the quality of life and survival of the patients, if diagnosed earlier. This paper describes four cases of primary HCC with varied manifestations of SCC due to bone metastases. The first patient presented primarily with the symptoms of bone pains corresponding to the bone metastases sites rather than symptoms of associated hepatic pathology and eventually developed SCC. The second patient, diagnosed as having HCC, developed extradural SCC leading to paraplegia during the course of illness, for which he underwent emergency laminectomy with posterior fixation. The third patient developed SCC soon after the primary diagnosis and had to undergo emergency laminectomy. Post laminectomy he had good neurological recovery. The Fourth patient presented primarily with radicular pains rather than frank paraplegia as the first manifestation of SCC.

关键词： Alpha feto protein External beam radiotherapy Hepatocellular carcinoma Laminectomy Spinal cord compression

Bone metastases from primary hepatocellular carcinoma simulating multiple myeloma

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Hepatobiliary & Pancreatic Diseases International 2005年第2期4卷 308-310页

作者： dinesh Chandra Doval Komal bhatia Ashok Kumar Vaid Kumar Prabhash Amarnath Jena Digant Hazarika Departments of Medical Oncology New Delhi India Departments of Medical Oncology Rajiv Gandhi Cancer Institute and Research Center Rohini Sector-5 Delhi 110085 India Departments of MRI Rajiv Gandhi Cancer Institute and Research Center Rohini Sector-5 Delhi 110085 India Departments of pathology Rajiv Gandhi Cancer Institute and Research Center Rohini Sector-5 Delhi 110085 India

A 65-year-old man presented with bone pains and anemia. Skull X-ray revealed multiple osteolytic lesions. The pa- tient was evaluated for multiple myeloma but detailed workup revealed the diagnosis of primary hepatocellular carcinoma (HCC) with osteolytic bone metastases. Thus, bone metastases due to HCC, although rare, should be considered in patients presenting with bone pains due to os- teolytic lesions.

关键词： hepatocellular carcinoma bone metastases multiple myeloma

Breast carcinoma with metastasis to the gallbladder:an unusual case report with a short review of literature

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Hepatobiliary & Pancreatic Diseases International 2006年第2期5卷 305-307页

作者： dinesh C Doval Komal bhatia Keechelat Pavithran Jai Bhagwan Sharma Ashok K Vaid Digant Hazarika Department of Medical Oncology Rajiv Gandhi Cancer Institute and Research Centre Rohini Sector-5 Delhi-110085India Department of Pathology Rajiv Gandhi Cancer Institute and Research Centre Rohini Sector-5 Delhi-110085India

Gallbladder metastases are very rare and usually arise from malignant melanoma, renal cell carcinoma and cervical carcinoma. Breast carcinoma tnetastatic to the gallbladder is extremely rare and only 4 cases have been reported in the English literature. We hereby report a 54-year-old lady who was diagnosed as having breast carcinoma and underwent modified radical mastectomy. One month after the operation, she developed acute abdomenal pain and underwent cholecystectomy after clinical investigation. Histopathological examination revealed metastasis to the gallbladder. Being considered a patient with tnetastatic breast carcinoma she was subjected to taxane and anthracycline-based palliative chemotherapy. Later she had CNS involvement and died of the progressive disease soon after few months.

关键词： gallbladder metastases breast