The concept of autonomous road vehicles has recently gained a great deal of technical respectability. Expected advantages over normal driver-controlled vehicles are through increased safety, reliability and fuel efficiency. This paper presents a novel experimental study enabling for the first time a full understanding of the aerodynamic flow development of a long vehicle platoon. Moving model experiments were carried out at the University of Birmingham Transient Aerodynamic Investigation (TRAIN) rig facility on a 1/20th scale eight lorry platoon with three constant vehicle spacings. Slipstream velocity and pressures, as well as simultaneous on-board vehicle surface pressure measurements were made. Results indicated a highly turbulent boundary layer development, with slipstream pulse peaks near the front of each lorry; similar to previous findings on flows around container freight trains. The drag coefficient of an isolated lorry was in agreement with previous studies. There are substantial reductions in aerodynamic drag for the non-leading platoon vehicles. Drag results plateaued towards a constant value within the platoon. Vehicle spacing affected drag values, with decreases of 57% observed for the closest spacing of half a vehicle length, demonstrating the aerodynamic benefits of platooning.
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In recent years, the concept of autonomous road vehicles has gained a great deal of technical respectability, with expected fuel benefits arising from running vehicles closely in platoons. However, the aerodynamics of such vehicles travelling in close proximity is still not understood. This paper presents for the first time a detailed study of drag benefits and the flow structure around a platoon of high-sided lorries, through conducting Delayed Detached Eddy Simulations (DDES). The lorry surface pressure and slipstream flow characteristics show good agreement with experimental data. Drag reductions of up to 70% have been observed for all trailing lorries in the platoon. Analysis of the flow field indicated highly turbulent regions on the top and sides of trailing lorries. Turbulent kinetic energy and Reynolds stresses were found to concentrate at the connection region between lorry cab and box. Spectral analysis of the side forces identified oscillating behaviour on each lorry in the platoon due to strong vortex shedding, suggesting that platooning lorries are potentially more likely to develop lateral instabilities than an isolated lorry. The study indicates that autonomous vehicle developers and operators should consider the significant drag reduction benefits of platooning against the risk associated with potential lateral instabilities.
Background
The application of neoadjuvant docetaxel and androgen deprivation therapy before radical prostatectomy has been clinically recognized as beneficial for the overall and progression‐free survival of patients with advanced prostate cancer. However, the mechanism underlying its clinical efficacy has not yet been reported.
Methods
We conducted a randomized comparative study on about 100 patients with high‐risk localized prostate cancer. Through nontarget metabolomics and tissue microarray immunohistochemistry, we investigated the difference in the endogenous metabolism of tumors in patients with prostate cancer who received or did not receive the neoadjuvant therapy.
Results
Many endogenous metabolic pathways, especially nucleotide synthesis, glutathione metabolism, citric acid cycle, and lipid synthesis, in prostate cancer tissue were altered after the neoadjuvant treatment, and the levels of nearly 90% of the differentially regulated metabolites were significantly decreased. Moreover, the levels of key enzymes in the cellular energy pathways were downregulated in tumor tissues and upregulated in adjacent tissues after the treatment. The positive and negative effects of the neoadjuvant therapy on normal and tumor cells in the prostate, respectively, resulted in the activation of the former and inhibition of the latter, which helped in reducing the number of tumors and weakened their aggressiveness.
Conclusions
From the perspective of endogenous metabolism in tumors, we have confirmed that neoadjuvant therapy can significantly downregulate important pathways for biosynthesis and energy metabolism in prostate cancer tissue, and thereby, inhibit tumor growth and metastasis.
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