Unsteady aerodynamic model of flexible flapping wing

Bio-inspired flapping wing has potential application to micro air vehicles (MAV). Due to the nature of lightweight and flexibility of micro flapping wing structures, elastic deformation as a result of aeroelastic coupling is inevitable in flapping motion. This effect can be significant and beneficial to the aerodynamic performance as revealed in the present investigation for a flexible flapping wing of variable camber versus a rigid one. Firstly a two dimensional (2D) unsteady aerodynamic model (UAM) based on potential flow theory has been extended from previous study. Both leading and trailing edge discrete vortices are included in the model with unsteady Kutta condition satisfied to fully characterize the unsteady flow around a flapping wing. A wall function is created to modify the induced velocity of the vortices in the UAM to solve the vortices penetration problem. The modified UAM is then validated by comparing with CFD results of a typical insect-like flapping motion from previous research. Secondly the UAM is further extended for a flexible flapping wing of camber variation. Comparing with a rigid wing in a prescribed plunging and pitching motion, the results show lift increase with positive camber in upstroke by mitigating negative lift. The results also agree well with CFD simulation. Thirdly the 2D UAM is extended to calculate the aerodynamic forces of a 3D wing with camber variation, and validated by CFD results. Finally the model is applied to aerodynamic analysis of a 3D flexible flapping wing with aeroelastic coupling effect. Significant increase of lift coefficient can be achieved for a flexible flapping wing of positive camber and twist in upstroke produced by the structure elastic deformation

A bio-inspired flapping wing rotor of variant frequency driven by ultrasonic motor

By combining the flapping and rotary motion, a bio-inspired flapping wing rotor (FWR) is a unique kinematics of motion. It can produce a significantly greater aerodynamic lift and efficiency than mimicking the insect wings in a vertical take-off and landing (VTOL). To produce the same lift, the FWR’s flapping frequency, twist angle, and self-propelling rotational speed is significantly smaller than the insect-like flapping wings and rotors. Like its opponents, however, the effect of variant flapping frequency (VFF) of a FWR, during a flapping cycle on its aerodynamic characteristics and efficiency, remains to be evaluated. A FWR model is built to carry out experimental work. To be able to vary the flapping frequency rapidly during a stroke, an ultrasonic motor (USM) is used to drive the FWR. Experiment and numerical simulation using computational fluid dynamics (CFD) are performed in a VFF range versus the usual constant flapping frequency (CFF) cases. The measured lifting forces agree very well with the CFD results. Flapping frequency in an up-stroke is smaller than a down-stroke, and the negative lift and inertia forces can be reduced significantly. The average lift of the FWR where the motion in VFF is greater than the CFF, in the same input motor power or equivalent flapping frequency. In other words, the required power for a VFF case to produce a specified lift is less than a CFF case. For this FWR model, the optimal installation angle of the wings for high lift and efficiency is found to be 30° and the Strouhal number of the VFF cases is between 0.3–0.36. View Full-Tex

Short landing performance and scale effect of a flapping wing aircraft

An investigation was made into the performance and scale effect of birdlike flapping wing aircraft in short landing. A flapping mechanism is proposed to transform a powered shaft rotation to an optimal kinematics of wing motion combining up-and-down stroke, pitching, and fore-and-back swing. An unsteady aerodynamic method (UAM) was developed based on potential flow theory, including the leading- and trailing-edge vortices generated by a flapping wing. After validation based on computational fluid dynamics (CFD) results, the method is used to calculate the aerodynamic forces of flapping wings. The flight dynamics model of the aircraft is built using Automated Dynamic Analysis of Mechanical Systems (ADAMS) software version 2012 interfacing with the UAM coded in Python. The coupling between the inertial force of the body motion and the aerodynamic forces from flapping wings and tailplane is incorporated into the numerical simulation of the aircraft landing. Taking a 0.196-kg birdlike aircraft model with a prescribed kinematics of flapping wing motion as an example, a parametric study was carried out in a small range of initial tailplane angles and subsequent flapping frequencies. Optimal parameters were obtained to reduce the forward and descending velocities of the aircraft to a minimum value for safe and short landing performance. The study is then extended to aircraft of different geometric scales in a range of 0.5–10 associated with a weight scale of 0.1–1,000. Based on the study, a method is developed to determine the required flapping frequency for birdlike aircraft of different scales to achieve a short landing target with the descending velocity reduced to a specified value. For the aforementioned example aircraft (geometric scale of 1), the flapping frequency is 4 Hz to reduce both descending and forward velocities to 50% of the landing performance in fixed-wing mode, while a birdlike aircraft on a geometric scale of 10 and landing weight of 196 kg requires a minimum flapping frequency of 1.25 Hz to achieve a 50% reduction of the descending and forward velocities compared with the same aircraft landing in fixed-wing mode

Effect of asymmetric feathering angle on the aerodynamic performance of a flyable bionic flapping-wing rotor

The current study involves an experimental as well as numerical study on the aerodynamic behavior of a flapping-wing rotor (FWR) with different feathering amplitudes (−20°–50°, −50°–20°, and −35°–35°). In order to fulfil the experimental test, an FWR which weighs 18.7 g is designed in this manuscript. According to the experimental and numerical results, it was observed that, compared with the cases under a zero average stroke angle, the cases under a positive average stroke angle or negative average stroke angle share a higher rotary speed given the same input voltage. Despite the fact that the negative average stroke angle would facilitate the generation of a higher rotary speed, the negative average stroke angle cases tend to generate the smallest lift-to-power ratio. On the other hand, the cases with a positive average stroke angle tend to share the largest lift-to-power ratio (about 1.25 times those of zero average stroke angle cases and about 1.6 times those of negative average stroke angle cases). The above study indicates that the application of a positive average stroke angle can provide an effective solution to further increase the aerodynamic performance of a bio-inspired FWR

Periostin identified as a potential biomarker of prostate cancer by iTRAQ-proteomics analysis of prostate biopsy

<p>Abstract</p> <p>Background</p> <p>Proteomics may help us better understand the changes of multiple proteins involved in oncogenesis and progression of prostate cancer(PCa) and identify more diagnostic and prognostic biomarkers. The aim of this study was to screen biomarkers of PCa by the proteomics analysis using isobaric tags for relative and absolute quantification(iTRAQ).</p> <p>Methods</p> <p>The patients undergoing prostate biopsies were classified into 3 groups according to pathological results: benign prostate hyperplasia (BPH, n = 20), PCa(n = 20) and BPH with local prostatic intraepithelial neoplasm(PIN, n = 10). Then, all the specimens from these patients were analyzed by iTRAQ and two-dimensional liquid chromatography-tandem mass spectrometry (2DLC-MS/MS). The Gene Ontology(GO) function and the transcription regulation networks of the differentially expressed were analyzed by MetaCore software. Western blotting and Immunohistochemical staining were used to analyze the interesting proteins.</p> <p>Result</p> <p>A total of 760 proteins were identified from 13787 distinct peptides, including two common proteins that enjoy clinical application: prostate specific antigen (PSA) and prostatic acid phosphatase(PAP). Proteins that expressed differentially between PCa and BPH group were further analyzed. Compared with BPH, 20 proteins were significantly differentially up-regulated (>1.5-fold) while 26 were significantly down-regulated in PCa(<0.66-fold). In term of GO database, the differentially expressed proteins were divided into 3 categories: cellular component(CC), molecular function (MF) and biological process(BP). The top 5 transcription regulation networks of the differentially expressed proteins were initiated through activation of SP1, p53, YY1, androgen receptor(AR) and c-Myc The overexpression of periostin in PCa was verified by western blotting and immunohistochemical staining.</p> <p>Conclusion</p> <p>Our study indicates that the iTRAQ technology is a new strategy for global proteomics analysis of the tissues of PCa. A significant up-regulation of periostin in PCa compared to BPH may provide clues for not only a promising biomarker for the prognosis of PCa but also a potential target for therapeutical intervention.</p

Screening potential lncRNA biomarkers for breast cancer and colorectal cancer combining random walk and logistic matrix factorization

Breast cancer and colorectal cancer are two of the most common malignant tumors worldwide. They cause the leading causes of cancer mortality. Many researches have demonstrated that long noncoding RNAs (lncRNAs) have close linkages with the occurrence and development of the two cancers. Therefore, it is essential to design an effective way to identify potential lncRNA biomarkers for them. In this study, we developed a computational method (LDA-RWLMF) by integrating random walk with restart and Logistic Matrix Factorization to investigate the roles of lncRNA biomarkers in the prognosis and diagnosis of the two cancers. We first fuse disease semantic and Gaussian association profile similarities and lncRNA functional and Gaussian association profile similarities. Second, we design a negative selection algorithm to extract negative LncRNA-Disease Associations (LDA) based on random walk. Third, we develop a logistic matrix factorization model to predict possible LDAs. We compare our proposed LDA-RWLMF method with four classical LDA prediction methods, that is, LNCSIM1, LNCSIM2, ILNCSIM, and IDSSIM. The results from 5-fold cross validation on the MNDR dataset show that LDA-RWLMF computes the best AUC value of 0.9312, outperforming the above four LDA prediction methods. Finally, we rank all lncRNA biomarkers for the two cancers after determining the performance of LDA-RWLMF, respectively. We find that 48 and 50 lncRNAs have the highest association scores with breast cancer and colorectal cancer among all lncRNAs known to associate with them on the MNDR dataset, respectively. We predict that lncRNAs HULC and HAR1A could be separately potential biomarkers for breast cancer and colorectal cancer and need to biomedical experimental validation

Aerodynamic performance of a flyable flapping wing rotor with passive pitching angle variation

The present work was based on an experimental study on the aerodynamic performance of a flapping wing rotor (FWR) and enhancement by passive pitching angle variation (PPAV) associated with powered flapping motion. The PPAV (in this study 10o~50o) was realized by a specially designed sleeve-pin unit as part of a U-shape flapping mechanism. Through experiment and analysis, it was found that the average lift produced by an FWR of PPAV was >100% higher than the baseline model, the same FWR of a constant pitching angle 30o under the same input power. It was also noted that the lift-voltage relationship for the FWR of PPAV was almost linear and the aerodynamic efficiency was also over 100% higher than the baseline FWR when the input voltage was under 6V. The aerodynamic lift or efficiency of the FWR of PPAV can be also increased significantly by reducing the weight of the wings. An FWR model was fabricated and achieved vertical take-off and free flight powered by 9V input voltage. The mechanism of PPAV function provides a feasible solution for aerodynamic improvement of a bio-inspired FWR and potential application to micro-air-vehicles (MAVs)

Knowledge-driven actions: Transforming higher education for global sustainability

Universities and, more broadly, higher education institutions (HEIs), need to use the knowledge they produce and their education of new professionals, to help solve some of the world´s greatest problems, as addressed by the Sustainable Development Goals (SDGs) set out by the United Nations (UN). Humanity is facing unprecedented challenges, most strikingly so in relation to climate change and loss of nature and biodiversity, as well as inequality, health, the economy, and a suite of issues related to the 2030 Agenda. Given this new reality in which the future of humans, along with other species, is at stake, it is time for HEIs and their stakeholders to systematically rethink their role in society and their key missions, and reflect on how they can serve as catalysts for a rapid, urgently needed and fair transition towards sustainability. The complexity of the issues at stake means that solutions should be part of a radical agenda that calls for new alliances and new incentives. It is also time for HEIs to make sustainability and SDG literacy core requisites for all faculty members and students. Sustainability education should bring students into contact with real-world problems an immersive experiences. Appreciating the greater good of both people and planet, and contributing to values beyond mere monetary gain will further enthuse and inspire students and faculty mentors alike. Ultimately, the educational culture at universities and HEIs needs to encourage students to learn via experimentation and critical thinking from multiple perspectives. This report is undoubtedly about the SDGs; however, it is important to realize that these will expire in 2030. We thus strongly recommend that HEIs, while being a part of that agenda, should also look ahead – not only to implementing the SDGs, but also to being intensively involved in crafting the next steps and goals beyond 2030. A long-term perspective needs to be adopted for both HEI activities and policies. The call this report makes is for universities and HEIs to play an active part in an agenda that has the consensus of 193 countries and aims to resolve some of the world’s most pressing problems, as stated in the 17 SDGs. The challenge is for HEIs to embrace the 2030 Agenda, because if they do not it will be difficult, if not impossible, to achieve the SDGs. The SDGs represent a unifying challenge for all universities and HEIs, and this must be reflected in plans and actions for research, education and outreach. HEIs have played a crucial role as bringers of societal enlightenment and change over the centuries, maintaining their role as free and critical institutions while also – to varying degrees – aiming to perform a service within societies. It is essential to maintain and encourage these important roles and enable HEIs to combine their traditions of critical thinking with problem-solving activities, while also adjusting their role in the light of societal changes. The future of humanity and our planet is under threat, and the need for critical thinking and societal change is therefore more pressing than ever. HEIs should inspire societal change when necessary, taking a leading role in the transitions necessary for humankind and emphasizing that the need for change is immediate. This also implies that HEIs should think critically about their own practices, curricula and research, and about how to motivate their employees, students and society at large to do the same