Experimental and Numerical Investigation of Near-field Rotor Aeroacoustics

This work presents comparisons between experimental and numerical estimates of near-field rotor aeroacoustics in hover. The experiments took place at the Kazan National Research Technical University named after A. N. Tupolev (Kazan Aviation Institute). A set of rotor blades with NACA-0012 aerofoil sections was used to obtain the sound pressure distribution using a linear array of microphones. It is shown that CFD and experimental results are in good agreement suggesting that the obtained test data can be useful as a validation case for development of CFD tools

Experimental and numerical study of rotor aeroacoustics

The work documents recent experiments at the Kazan National Research Technical University named after A.N. Tupolev (Kazan Aviation Institute), related to helicopter acoustics. The objective is to measure nar-field acoustics of rotors in hover and provide data suitable for computational fluid dynamics validation. The obtained set of data corresponds to a scaled rotor of known planform and the results are of high resolution. An advantage of the current dataset is that direct near-field acoustic data is made available and this allows for easy and direct comparisons with computational fluid dynamics predictions, without the need to use far-field aeroacoustic methods

Experimental investigation of wing tip vortices in the near-field

Results of an experimental investigation related to near-field wing tip vortices are presented. The measurements were carried out using a PIV-system in T-1K wind tunnel of KNRTU-KAI. Q-criterion and crosssectional lines method were used to determine vortex core locations, which showed a good agreement. It is shown that the circulation of tip vortices remains constant at low to moderate angles of attack, and decreases in the stream-wise direction for higher angles of attack. It is also shown that the vortex core radius increases in the stream-wise direction, taking larger values at higher angles of attack

Experimental investigation of wing tip vortices in the near-field

Results of an experimental investigation related to near-field wing tip vortices are presented. The measurements were carried out using a PIV-system in T-1K wind tunnel of KNRTU-KAI. Q-criterion and crosssectional lines method were used to determine vortex core locations, which showed a good agreement. It is shown that the circulation of tip vortices remains constant at low to moderate angles of attack, and decreases in the stream-wise direction for higher angles of attack. It is also shown that the vortex core radius increases in the stream-wise direction, taking larger values at higher angles of attack

Experimental and Numerical Investigation of Near-field Rotor Aeroacoustics

This work presents comparisons between experimental and numerical estimates of near-field rotor aeroacoustics in hover. The experiments took place at the Kazan National Research Technical University named after A. N. Tupolev (Kazan Aviation Institute). A set of rotor blades with NACA-0012 aerofoil sections was used to obtain the sound pressure distribution using a linear array of microphones. It is shown that CFD and experimental results are in good agreement suggesting that the obtained test data can be useful as a validation case for development of CFD tools

Analysis of molecular phenotypes in normal mucosa and colorectal cancer in embryonic anatomical parts of the colon

Background: Differences in the embryonic development of the colonic mucosa determine the physiological embryonic-anatomical asymmetry of its structure and can manifest themselves via different molecular phenotypes (expression profiles) of the colon segments. These molecular characteristics are hypothesized to determine differences in the carcinogenesis mechanisms and influence the prognosis of right- or left-sided colorectal cancer (CRC). Studies of the tumors molecular phenotypes depending on their localization may be of interest for assessment of the prognosis and choice of treatment for CRC. Aim: To perform comparative analysis of molecular phenotypes of the normal colonic mucosa and adenocarcinoma CRC tissues depending on the natural embryonic anatomic asymmetry of the colon. Materials and methods: We performed a retrospective study of molecular phenotypes (mRNA expression of 61 genes) from different embryonic-anatomical parts of healthy colon and CRC. The normal group included 254 samples of mucosa from three different parts of the colon from 74 healthy donors who had no cancer and no organic abnormalities of the colon, including 90 samples from the right colon, 116 from the left colon, and 48 from the rectum. The CRC group consisted of 154 samples of localized stage T1–4N0–2M0 adenocarcinoma from 154 patients who had not received neoadjuvant radio- and chemotherapy, including 40 samples from the right colon, 54 from the left colon, and 60 from the rectum. The relative mRNA abundance of 61 genes was assessed by reverse-transcriptase polymerase chain reaction. In both groups, the resulting expression phenotypes were compared between the anatomical parts of the colon. Statistical management of the data included the discriminant analysis with stepwise inclusion of variables. Results: Based on the assessment of the mRNA level of the studied genes, a discriminant model was built that allows for classification of the normal group samples according to their anatomic origin in the colon with an accuracy of 95.8%. The most significant (p 0.05) for classification are the following 19 genes: CCND1, SCUBE2, TERT, BAG1, NDRG, IL1b, IL2Ra, IL7, ESR1, TGFb, IGF1, MMP9, MMP11, PAPPA, CD45, CD69, TLR2, TLR4, LIFR. The discriminant model built for the CRC group included 27 genes and made it possible to differentiate samples from three parts of colon with an accuracy of 75.2%. A statistically significant (p 0.05) contribution to the samples differentiation by the discriminant model was made by the COX-2, BIRC5, LIFR, TPA, IL1b, MMP11, MMP7, and P16INK4A genes. When combining samples from the two groups into one model in accordance with their embryonic-anatomical origin, there was a clear separation of tumor tissue samples and healthy colonic mucosa in the discriminant function space. Conclusion: The analysis of CRC gene expression profiles using the discriminant model showed that genetic changes in the colonic mucosa in CRC flatten the molecular phenotypic boundaries of the embryonic-anatomical parts. These changes are specific to CRC, forming a particular “pathological” molecular phenotype

Al and Ti location in the MFI orthorhombic HZSM-5 framework. DFT calculation and neutron diffraction experiment

Abstract For the first time the neutron diffraction study of HZSM-5 zeolites with the general composition of (H1+x)[Al3+xSi4+12-xO24] × wH2O in the orthorhombic approximation (sp. gr. Pnma, z = 8) and initial silicate modules Si/Al = 12, 25, 40 was carried out. As a result, the composition was refined, the distribution of Al3+ ions over the tetrahedral sites (T sites) of the structure was found, and their content in each of them was estimated. It was found that T sites occupation in HZSM-5 structure differ depending on Si/Al, while samples with the same silicate module (Si/Al = 40) obtained under different synthesis conditions differ in the distribution of Al3+ ions over T sites of the structure. It was shown that the calculation of HZSM-5 zeolites crystal structure with substitutions in T sites performed using the VASP 5.2 program with different optimizations (atomic coordinates and unit cell parameters) can only reveal the most thermodynamically energetically favorable sites for Si4+ atoms substitution with other atoms (aluminum and titanium) without predicting their content in each site and regardless zeolite synthesis conditions and type of substituent atom. The relationship between HZSM-5 zeolites catalytic properties and silicate module (Si/Al, Si/Ti) was found and it cannot be ruled out that HZSM-5 catalytic activity is related to Ti4+ ions distribution over the tetrahedral sites of the structure. Graphical Abstrac