scholarly journals Experimental Research on the Similarity of Rime Icing on a Cylinder Rotating around Its Horizontal Axis

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Lei Shi ◽  
Yan Li ◽  
Wenfeng Guo ◽  
Ce Sun
Keyword(s):  
Wind Tunnel ◽  
Translational Motion ◽  
Experimental Studies ◽  
Similarity Criterion ◽  
Test System ◽  
Test Time ◽  
Shape Similarity ◽  
Rotational Model ◽  
Research Results ◽  
Ice Shapes

Ice accumulation on the blade of a wind turbine surface seriously threatens the operational safety of the turbine; therefore, the research on this problem is very important. In this paper, a new similarity criterion of icing shape for a rotational model was proposed based on the similarity criterion for translational motion models in the aviation field, and experimental studies on the similarity of the rotational model icing were carried out. To validate the similarity criterion, icing wind tunnel tests were carried out with aluminum cylinders with diameters of 40 mm and 20 mm. Key parameters for the experiment, such as wind speed, temperature, liquid water content, medium volume diameter, and test time, were selected based on the criterion. All the icing tests were carried out in a new self-designed icing wind tunnel test system based on natural low-temperature conditions. The icing shapes observed in the tests were confirmed after many repetitions. To quantitatively analyze the similarity between different sizes of ice shapes, a dimensionless method for evaluating the similarity of ice shapes of different sizes was defined based on the typical characteristics of ice shapes. The research results show that the similarity score between two sizes of ice shapes under different test conditions is 81%~90%. The accuracy and applicability of the icing shape similarity criterion were thus validated. The research results in this paper lay a theoretical and experimental foundation for exploring the icing shape similarity of a rotating model.

Framework and performance analysis of college English testing system based on data mining technology

2021 ◽  
pp. 1-11
Author(s):  
Liu Narengerile ◽  
Li Di ◽  
Keyword(s):  
Data Mining ◽  
Test System ◽  
Test Time ◽  
Testing System ◽  
Test Results ◽  
System Software ◽  
Examination System ◽  
Mining Technology ◽  
College English ◽  
And Performance

At present, the college English testing system has become an indispensable system in many universities. However, the English test system is not highly humanized due to problems such as unreasonable framework structure. This paper combines data mining technology to build a college English test framework. The college English test system software based on data mining mainly realizes the computer program to automatically generate test papers, set the test time to automatically judge the test takers’ test results, and give out results on the spot. The test takers log in to complete the test through the test system software. The examination system software solves the functions of printing test papers, arranging invigilation classrooms, invigilating teachers, invigilating process, collecting test papers, scoring and analyzing test papers in traditional examinations. Finally, this paper analyzes the performance of this paper through experimental research. The research results show that the system constructed in this paper has certain practical effects.

Treated Textile Electrostatic Properties Study

2020 ◽  
Vol 992 ◽  
pp. 439-444
Author(s):  
I.V. Cherunova ◽  
S.S. Tashpulatov ◽  
S.V. Kurenova
Keyword(s):  
Experimental Studies ◽  
Material Structure ◽  
Ministry Of Education ◽  
Research Results ◽  
Textile Materials ◽  
Electrostatic Properties ◽  
Film Forming ◽  
Study Results ◽  
Water Proofing ◽  
Textile Fabric

In the article research results are presented, which aim to provide treated textile electrostatic properties study. In the article research results are presented, which aim to provide find out abilities of an anti-electrostatic treatment and binding agents for it in treatment of special textile materials and their dependance from modes of operating textile washing. Results of determine a composition and abilities of a functional impregnation; develop a method to study values of electrostatic field for tribocharging conditions of textile materialsare; experimental studies of electrostatic values of materials with functional treatment depending on operating washing modes also presented here. Study results allowed to establish efficiency of the proposed combination of anti-electrostatic active composition based on 5 % solution of dialkyldimethylammonium chloride with a binding agent with the effect to preserve the treatment in the material structure and content of which is 4 % in application of textile fabric with widely used fiber content (cotton 53 %, polyester + oil and water-proofing finish). Acrylic dispersion is stable film-forming component suitable in preserving anti-electrostatic treatment on the surface of a textile material. The research was made in Don State Technical University within the framework of State Assignment of the Ministry of education and science of Russia under the project 11.9194.2017/BCh.

scholarly journals The Anti-Neuroinflammatory Effect of Fuzi and Ganjiang Extraction on LPS-Induced BV2 Microglia and Its Intervention Function on Depression-Like Behavior of Cancer-Related Fatigue Model Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Songwei Yang ◽  
Yantao Yang ◽  
Cong Chen ◽  
Huiqin Wang ◽  
Qidi Ai ◽  
...  
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Inflammatory Mediators ◽  
Critical Role ◽  
Chinese Herb ◽  
Experimental Studies ◽  
Research Results ◽  
Cancer Related Fatigue

The Chinese herb couple Fuzi and Ganjiang (FG) has been a classic combination of traditional Chinese medicine that is commonly used clinically in China for nearly 2000 years. Traditional Chinese medicine suggests that FG can treat various ailments, including heart failure, fatigue, gastrointestinal upset, and depression. Neuroinflammation is one of the main pathogenesis of many neurodegenerative diseases in which microglia cells play a critical role in the occurrence and development of neuroinflammation. FG has been clinically proven to have an efficient therapeutic effect on depression and other neurological disorders, but its mechanism remains unknown. Cancer-related fatigue (CRF) is a serious threat to the quality of life of cancer patients and is characterized by both physical and psychological fatigue. Recent studies have found that neuroinflammation is a key inducement leading to the occurrence and development of CRF. Traditional Chinese medicine theory believes that extreme fatigue and depressive symptoms of CRF are related to Yang deficiency, and the application of Yang tonic drugs such as Fuzi and Ganjiang can relieve CRF symptoms, but the underlying mechanisms remain unknown. In order to define whether FG can inhibit CRF depression-like behavior by suppressing neuroinflammation, we conducted a series of experimental studies in vitro and in vivo. According to the UPLC-Q-TOF/MSE results, we speculated that there were 49 compounds in the FG extraction, among which 30 compounds were derived from Fuzi and 19 compounds were derived from Ganjiang. Our research data showed that FG can effectively reduce the production of pro-inflammatory mediators IL-6, TNF-α, ROS, NO, and PGE2 and suppress the expression of iNOS and COX2, which were related to the inhibition of NF-κB/activation of Nrf2/HO-1 signaling pathways. In addition, our research results revealed that FG can improve the depression-like behavior performance of CRF model mice in the tail suspension test, open field test, elevated plus maze test, and forced swimming test, which were associated with the inhibition of the expression of inflammatory mediators iNOS and COX2 in the prefrontal cortex and hippocampus of CRF model mice. Those research results suggested that FG has a satisfactory effect on depression-like behavior of CRF, which was related to the inhibition of neuroinflammation.

scholarly journals Smart but Evil? Student-Teachers’ Perception of Educational Researchers’ Epistemic Trustworthiness

AERA Open ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 233285841986815
Author(s):  
Samuel Merk ◽  
Tom Rosman
Keyword(s):  
Preservice Teachers ◽  
Student Teachers ◽  
Exploratory Study ◽  
Classroom Practice ◽  
Scientific Evidence ◽  
Experimental Studies ◽  
Epistemic Beliefs ◽  
Research Results ◽  
Research Findings ◽  
Integrate Research

In-service and preservice teachers are increasingly required to integrate research results into their classroom practice. However, due to their limited methodological background knowledge, they often cannot evaluate scientific evidence firsthand and instead must trust the sources on which they rely. In two experimental studies, we investigated the amount of this so-called epistemic trustworthiness (dimensions expertise, integrity, and benevolence) that student-teachers ascribe to the authors of texts who present classical research findings (e.g., learning with worked-out examples) that allegedly were written by a practitioner, an expert, or a scientist. Results from the first exploratory study suggest that student-teachers view scientists as “smart but evil,” since they rate them as having substantially more expertise than practitioners, while also being less benevolent and lacking in integrity. Moreover, results from the exploratory study suggest that evaluativistic epistemic beliefs (beliefs about the nature of knowledge) predict epistemic trustworthiness. A preregistered conceptual replication study (Study 2) provided more evidence for the “smart but evil” stereotype. Further directions of research as well as implications for practice are discussed.

scholarly journals Characterization and first results from LACIS-T: a moist-air wind tunnel to study aerosol–cloud–turbulence interactions

2020 ◽  
Vol 13 (4) ◽  
pp. 2015-2033 ◽  
Author(s):  
Dennis Niedermeier ◽  
Jens Voigtländer ◽  
Silvio Schmalfuß ◽  
Daniel Busch ◽  
Jörg Schumacher ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Spatial Scales ◽  
Experimental Studies ◽  
Field Measurements ◽  
Hygroscopic Growth ◽  
Moist Air ◽  
Aerosol Cloud ◽  
Cloud Microphysical Processes ◽  
First Results ◽  
Microphysical Processes

Abstract. The interactions between turbulence and cloud microphysical processes have been investigated primarily through numerical simulation and field measurements over the last 10 years. However, only in the laboratory we can be confident in our knowledge of initial and boundary conditions and are able to measure under statistically stationary and repeatable conditions. In the scope of this paper, we present a unique turbulent moist-air wind tunnel, called the Turbulent Leipzig Aerosol Cloud Interaction Simulator (LACIS-T) which has been developed at TROPOS in order to study cloud physical processes in general and interactions between turbulence and cloud microphysical processes in particular. The investigations take place under well-defined and reproducible turbulent and thermodynamic conditions covering the temperature range of warm, mixed-phase and cold clouds (25∘C>T>-40∘C). The continuous-flow design of the facility allows for the investigation of processes occurring on small temporal (up to a few seconds) and spatial scales (micrometer to meter scale) and with a Lagrangian perspective. The here-presented experimental studies using LACIS-T are accompanied and complemented by computational fluid dynamics (CFD) simulations which help us to design experiments as well as to interpret experimental results. In this paper, we will present the fundamental operating principle of LACIS-T, the numerical model, and results concerning the thermodynamic and flow conditions prevailing inside the wind tunnel, combining both characterization measurements and numerical simulations. Finally, the first results are depicted from deliquescence and hygroscopic growth as well as droplet activation and growth experiments. We observe clear indications of the effect of turbulence on the investigated microphysical processes.

Experimental investigation of the icing scaling test method for a rotating cone

2018 ◽  
Vol 233 (9) ◽  
pp. 3368-3380
Author(s):  
Fei Zhang ◽  
Lifen Zhang ◽  
Yundan Li ◽  
Zhenxia Liu ◽  
Pengfei Zhu
Keyword(s):  
Wind Tunnel ◽  
Similarity Theory ◽  
Maximum Error ◽  
Test Method ◽  
Test Facility ◽  
Stagnant Point ◽  
Ice Conditions ◽  
Trajectory Similarity ◽  
Rotating Cone ◽  
Ice Shapes

One of the reliable methods of studying engine icing is to carry out testing in an icing wind tunnel. Due to the operational limitations of test facility, model-size scaling is adopted. An icing scaling test method for the rotating cone is established based on the dimensional analysis coupled with similarity theory and evaluated by considering the rotating effect. Similarity parameters are determined in the following five aspects: flow field similarity, droplet trajectory similarity, water catch similarity, heat balance similarity, and rotating characteristics similarity. Experimental icing tests have been performed at rime and glaze ice conditions to evaluate the scaling method in a closed-loop icing wind tunnel. Results show that the maximum error between the reference and scale ice shapes occurs at the stagnant point. On the areas apart from this, there is a significantly smaller error. Hence, the scaling test method is proven to be effective and reliable and can provide a theoretical basis for parameter selection of the ice wind tunnel tests.

scholarly journals Wind Loading on Scaled Down Fractal Tree Models of Major Urban Tree Species in Singapore

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 803
Author(s):  
Woei-Leong Chan ◽  
Yong Eng ◽  
Zhengwei Ge ◽  
Chi Wan Calvin Lim ◽  
Like Gobeawan ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Tree Species ◽  
Experimental Studies ◽  
Velocity Profiles ◽  
Aerodynamic Load ◽  
Tree Crowns ◽  
Urban Tree ◽  
Crown Shape ◽  
Optical Porosity ◽  
Tree Models

Estimation of the aerodynamic load on trees is essential for urban tree management to mitigate the risk of tree failure. To assess that in a cost-effective way, scaled down tree models and numerical simulations were utilized. Scaled down tree models reduce the cost of experimental studies and allow the studies to be conducted in a controlled environment, namely in a wind or water tunnel, but the major challenge is to construct a tree model that resembles the real tree. We constructed 3D-printed scaled down fractal tree models of major urban tree species in Singapore using procedural modelling, based on species-specific growth processes and field statistical data gathered through laser scanning of real trees. The tree crowns were modelled to match the optical porosity of real trees. We developed a methodology to model the tree crowns using porous volumes filled with randomized tetrahedral elements. The wind loads acting on the tree models were then measured in the wind tunnel and the velocity profiles from selected models were captured using particle image velocimetry (PIV). The data was then used for the validation of Large Eddy Simulations (LES), in which the trees were modelled via a discretized momentum sink with 10–20 elements in width, height, and depth, respectively. It is observed that the velocity profiles and drag of the simulations and the wind tunnel tests are in reasonable agreement. We hence established a clear relationship between the measured bulk drag on the tree models in the wind tunnel, and the local drag coefficients of the discretized elements in the simulations. Analysis on the bulk drag coefficient also shows that the effect of complex crown shape could be more dominant compared to the frontal optical porosity.

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