13 research outputs found
Simulation and Optimisation of unsteady aerodynamic performance of a 2D VAWT rotor: With emphasis on airfoil design
No full textAirfoil design plays an important role in improving the performance of Vertical Axis Wind Turbines(VAWTs). The aim of this thesis is to arrive at optimal airfoil geometries to enhance the performance of VAWTs and analyse the performance of these optimal airfoils under steady and unsteady operation conditions of the rotor. The airfoil design is aimed at rotors operating in the Reynolds number range of 10ዀ. The inverse airfoil design approach is used to arrive at the airfoil geometries. The design process involves formulating a multiobjective optimisation problem with the aerodynamic and structural performance of the airfoil as objectives.After a comprehensive literature study, the objective derived by Ferreira and Geurts [25] was chosen for its suitability to the current work. The aerodynamic performance of the airfoil is gauged by the ratio of lift slope and drag coefficient. The structural objective is limited to the flapwise bending stiffness. To account for the weather impact, the aerodynamic objective also includes the effect of surface roughness. An effective optimisation framework is built with the Non-dominated Sorting Genetic Algorithm(NSGA-II) to arrive at the Pareto front with best suitable airfoils for VAWTs. This framework is coupled with XFOIL which evaluates the geometries and another python based framework, Distributed Evolutionary Algorithms in Python(DEAP) which helps in setting up the genetic algorithm. Once the convergence is reached, few airfoils from the final Pareto front are chosen for further analysis.Based on the literature study, the Actuator Cylinder Model(ACM) was chosen to simulate the performance of the airfoils in a VAWT rotor. The performance of the selected airfoils were analysed under steady flow conditions with the ACM. To account for the effects of unsteady flow over the airfoil, a Beddoes-Leishman type dynamic stall model formulated by the Risø national laboratories was integrated into the AC Model loop along with a correction to the effective angle of attack. The inviscid part of this model was validated with another AC Modelcode from Li [42] and the inviscid panel method 푈2퐷푖푉퐴 [65].The performance of the optimised airfoils is an improvement over the performance of the NACA airfoils of similar thicknesses which proves that the optimisation process has been successful. The performance of the airfoils in steady flow indicates that the power performance of the airfoil suffers more from the surface roughness as the thickness of the airfoil increases. The thicker airfoils perform better at high solidity applications at low tip speed ratios. The range of operational tip speed ratios decreases as the airfoils become thicker.The performance of these airfoils under the effects of unsteady flow under the inviscid flow assumption provides an overview of the differences in the performance of the airfoils under unsteady flow conditions. The range of tip speed ratios where the airfoils show their best performance moves towards higher values indicating that under unsteady flow effects, the rotor needs to operate at a higher rotational velocity to achieve its best performance. However, to obtain a better insight on the performances of the airfoil under unsteady flow effects, further studies with the complete validated Risø model have to be carried out.Aerospace Engineerin
Disaster Resilience in Vulnerable cities through Neighbourhood Development: A case of Chennai
No full textAbstractThis paper follows the discipline of Urban Design to elaborate the concepts of disaster resilience at the neighbourhood level for the collective development of Chennai city. The increased inflow and use of resources attributed to the growing urban population creates a pressure on the various natural systems, increasing their vulnerability to multiple attacks from natural and man-made forces. Hence the future adaptability of cities is important for its growth in the aftermath of a disaster strike. The intent of this research is thus to develop a framework of strategies for an emergency response programme and to develop a design scheme to make cities resilient, through neighbourhood development. A sample precinct of Chepauk was taken up for the design demonstration after a detailed analysis of the same, addressing various physical factors such as land use, open spaces, connectivity networks, physical and social infrastructure, built density, ecology and emergency response mechanism
A Study on Cost Effectiveness and Security of VANET Technologies for Future Enhancement
No full textAbstractIntelligent Transport System (ITS) is an advanced application which provides web enabled services for traffic and transport system, which results in a safer, coordinated traffic network system. ITS is very effectively used in VANET (Vehicular Ad-hoc Network), which is a spontaneous creation of wireless network of vehicles for exchanging information between them, for improved transport and traffic management and to enable various users to be sufficiently informed about the road and make safer and smarter decisions on road by using transport networks. As the technology has to be used widely, there is a high need for a low cost VANET technology with high security and Quality of Service. To go for any further developments, a thorough analysis on the available technologies is essential to get a closer view on the current scenario. The result of this study can open doors for a better technology for future VANETs. This paper considers a few existing technologies such as CROWN, Vehicular Cloud and VANET-Cloud and a comparison on these is carried out
Design of NEMS Based Intraocular Pressure Sensing System
No full textAbstractGlaucoma is one of the leading causes of irreversible blindness. The change in intraocular pressure (IOP) inside the anterior chamber of the eye beyond its normal limit leads to this condition which initially affects the peripheral vision and if left untreated, results in permanent blindness. Early detection of elevation in IOP helps to slow down the disease progress. Thus a highly precise, cost effective, miniaturized pressure sensor is an important need for sensing the IOP. In the present work, the piezoresistivity of Single Walled Carbon Nano Tubes (SWCNT) is exploited to design a diaphragm based Nano-Electro-Mechanical Systems (NEMS) pressure sensor. Finite Element Method simulation is then performed to find the change in resistance ofthe piezoresistive material. This change in resistance results a change in output voltage corresponding to the pressure applied, which can be measured by an interfacing circuitry consisting of a low voltage amplifier andlow power-high speed Analog to Digital Converter (ADC). The resultant pressure sensor response is found to be highly linear and its sensitivity can be increased by changing diaphragm dimensions
Primary Peritoneal Clear Cell Carcinoma Presenting with Nonspecific Gastrointestinal Symptoms in a 39-Year-Old Woman: A Case Report
No full textIntroduction: Primary peritoneal clear cell carcinoma (PPCCC) is a rare abdominal tumor, affecting 7 out of every million people. Its vague presenting signs and symptoms often lead to delayed diagnosis and poor prognosis. We present a case involving a young woman with anemia and abdominal discomfort who on further investigation had a 26-cm abdominal tumor identified to be PPCCC. Multimodal therapy with tumor debulking and chemotherapy was pursued. Given the aggressive nature of PPCCC, any clinical suspicion of peritoneal carcinoma should prompt thorough diagnostic evaluation. Case Presentation: A 39-year-old woman with menorrhagia and peptic ulcer disease presented with abdominal discomfort of 2 days duration. She initially had headaches managed with ibuprofen. Following this, she had generalized abdominal pain with bloating that worsened with food and had no relief with use of stool softeners. She had associated dizziness with palpitations, chest pressure, and exertional dyspnea. In the emergency department, the patient was mildly tachycardic but otherwise stable. On exam, she had a distended abdomen with generalized tenderness and normoactive bowel sounds. Labs showed normocytic anemia with a hemoglobin of 5.2 mg/dL. Electrocardiogram and abdominal and chest X-rays were normal. A non-contrast computed tomography of the abdomen and pelvis showed a fibroid uterus and posterior displacement of multiple bowel loops by a large septate cystic mass (13.5 × 26.0 × 26.7 cm) occupying the entire abdominal cavity. Elevated CA 125 and CA 19-9 were also noted. She underwent exploratory laparotomy with mass resection, partial omentectomy, left colectomy (given extension into transverse colon), appendectomy, and total abdominal hysterectomy with bilateral salpingectomy. Biopsy and immunohistochemical staining (positive for PAX-8, ER, P53, P16, Napsin A and negative for PR and WT-1) confirmed mass as stage IIIB PPCCC. There was no evidence of malignancy in other tissue samples. The patient was discharged with a plan for outpatient chemotherapy and genetic counseling. Conclusion: Given the rarity of PPCCC, our case highlights how increased clinical vigilance and prompt multidisciplinary efforts are essential for an accurate diagnosis, especially in younger patients to not delay management. Currently, there are no established management guidelines; however, initial treatment with surgical debulking followed by chemotherapy is often practiced
Development and charactersisation of MCP-1 and ɑ-MSH fused with elastin-like polypeptide nanoparticles to treat pressure ulcers caused by spinal cord injury
No full textPressure ulcers are a challenging complication seen in patients with spinal cord injury (SCI). They decrease the patients' quality of life and cause physical, social, and physiological burdens. There is a delay in skin wound healing after SCI, which we hypothesize is due to a decrease in the expression of chemokines and neuropeptides that recruit macrophages to the wound. In this study, we developed and characterized elastin-like polypeptide (ELP) nanoparticles incorporating the chemokine MCP-1 (MCP-ELP), and the neuropeptide a-MSH (a-MSH-ELP). These chemokines and neuropeptides are important for modulating the inflammatory phase of wound healing via recruiting different macrophages. The fusion protein approach of ELP conjugation is proven to deliver better bioavailability and enhance stability. For purification of fusion proteins, we used inverse transition cycling by exploiting the phase transitioning property of ELP. We obtained single purified bands in SDS-PAGE, with sizes ranging from ~200 nm to 350 nm for MCP-ELP and a-MSH-ELP, respectively. The stability test suggested that fusion nanoparticles and native proteins stayed stable in PBS for 7 days but degraded in elastase after day 0. To verify the bioactivity of the fusion proteins, a transwell migration assay was conducted with the monocyte-like cell line THP-1, which expresses receptors to both MCP-1 and a-MSH. THP-1 monocytes migrated significantly more in the presence of a-MSH-ELP vs a-MSH (p0.0004), and a non-statistically significant trend towards better proliferation compared with native MCP-1 (p=0.0748). a-MSH-ELP showed a trend of better proliferation, but the effect was not statistically significant. Human dermal fibroblasts and keratinocytes showed a trend of higher proliferation with 0.1 nM to 1 µM that was not statistically significant. In conclusion, we successfully developed, purified, and characterized MCP-ELP and a-MSH-ELP. Both have biological activities in vitro that are equal to, and sometimes even better than, the native proteins, and could advance to in vivo testing.M.S.Includes bibliographical reference
Zollinger-Ellison Syndrome Unmasked during Hiatal Hernia Evaluation: A Case Report
No full textIntroduction: Zollinger-Ellison syndrome (ZES) is a rare entity consisting of tumors called gastrinomas in the stomach, pancreas, and duodenum. It usually presents with symptoms of acid hyper secretion including abdominal pain, diarrhea, nausea, and vomiting and can be misdiagnosed as peptic ulcer disease, hiatal hernia, and gastroesophageal reflux disease. Case Presentation: We report a case of ZES presenting duodenal perforation and later mimicking a hiatal hernia. This case highlights a complex presentation and underscores the importance of thorough evaluation, multidisciplinary management, and including rare diagnosis in the differential. Our patient presented to the hospital with nausea, back pain, and abdominal pain, and imaging demonstrated a perforated duodenum which was managed with surgical repair. Following surgery, the patient continued to have worsening nausea and acid reflux which was deemed to be due to a hiatal hernia noted on prior imaging until an esophagogastroduodenoscopy (EGD) was performed which confirmed the diagnosis of ZES. Conclusion: Our case emphasizes the importance and necessity of doing an EGD in a timely fashion to ensure that a diagnosis of rare ZES is not missed
Social media use and the relationship with colorectal cancer screening among foreign-born populations in the United States
No full textBackground: Social media (SM) has emerged as a tool for health-related usage among US adults, including cancer screening promotion. Here, we aimed to assess the differences in health-related SM use between US and foreign-born adults and the relationship between health-related SM use and colorectal (CRC) screening practices.
Methods: Using data from the fifth edition of the National Cancer Institute\u27s Health Information National Trends Survey (HINTS 5), cycle 2, we compared the differences in health-related SM use between US and foreign-born adults and the effects of SM use on CRC screening by country of birth. We included adults aged 50-75 and excluded participants with a history of CRC. The primary endpoint was CRC screening, which was determined by self-reported CRC screening using colonoscopy, sigmoidoscopy, or stool occult blood testing.
Results: Our study included 1,812 adults, of whom 236 (13.0%) were foreign-born. Most participants (72.1%) reported undergoing CRC screening. Interestingly, we found no discernible difference in health-related SM use [odds ratio [OR] 0.91; 95% CI (0.49, 1.69)] between US and foreign-born adults. Furthermore, our analysis revealed that SM use did not influence CRC screening practices among either group (US-born: 0.88 [95% CI: 0.50, 1.52], foreign-born 0.52 [0.10, 2.51]).
Conclusion: Contrary to previous studies, which showed a positive relationship between SM use and satisfactory health-related practices, we found that although foreign-born adults use SM as much as US-born adults, there was no significant relationship between SM use and CRC screening
Trends in incidence rates of hepatocellular carcinoma and stage at diagnosis by demographics in the U.S. from 2004 to 2021: a joinpoint analysis of the SEER database.
No full textOBJECTIVES: Hepatocellular carcinoma (HCC) is the 13th most common cancer in the U.S., causing approximately 30,000 deaths annually. Incidence has risen substantially over recent decades. This study examines trends in age-adjusted HCC incidence from 2004 to 2021.
MATERIALS AND METHODS: Incidence data for HCC (ICD-10 C22.0) from 2004 to 2021 were obtained from the Surveillance, Epidemiology and End Results (SEER) registry, representing 48% of the U.S. population. Rates were age-adjusted to the 2000 U.S. standard population and stratified by sex, race/ethnicity, age, and stage at diagnosis. Annual percentage changes (APCs) were calculated using Joinpoint regression with statistical significance set at
RESULTS AND CONCLUSION: From 2004 to 2015, overall HCC incidence increased (APC 3.16
Playing Action Video Games a Key to Cognitive Enhancement
No full textAbstractIn this paper, we aim to analyse the impact of training on improvement in cognitive abilities and performance of the subjects playing single player action video game. Recent research indicates that playing Action video games improve cognitive abilities. However no study has exploited the novel technique, Empirical Mode Decomposition in the field of action video games. Empirical mode decomposition was used to extract various features by decomposing EEG data into intrinsic mode functions. Intrinsic mode functions were used to calculate linear features like standard deviation, phase and energy. K- Nearest Neighbour & Linear Discriminant Analysis classifiers were used to classify the subject based on the changes in features extracted due to the impact of training. Psychological tests conducted before and after the training, positively affirm that training improves cognitive abilities like reaction time and reduces stress level
