Evaluation of the steady state performance of a squirrel cage induction motor using per-phase equivalent circuit

The performance evaluation of cage induction motor continues to receive tremendous attention because of its vital effect on the overall system stability. The model has predicted the behavior of cage induction motor under different operating conditions and in selecting the appropriate motor for a specific load application. There is often a challenge when a squirrel cage induction motor is connected to a time-varying load, particularly when the motor is selected without considering the effects of pulsating torques. The usual method used for steady state analysis of induction motors is the equivalent circuit method. Using the per phase equivalent circuit of the induction motor, stator current and referred rotor current were computed using simple circuit analysis. Once the currents are available, then power can be computed because the voltage is already known.

Research and Application of Double-Reheat Boiler in China

The ultra-supercritical (USC) double-reheat technology is an immediate area of research focus in China, since the thermal efficiency of USC double-reheat unit is higher than the USC single-reheat unit. The parameters and capacity of USC double-reheat unit in China have made major breakthroughs, and the thermal efficiency of the units are as high as 47–48%, which is the highest in the world. USC double-reheat boiler is one of the most important devices for USC double-reheat unit, and the design concept and precision have a vital effect on the operation of boiler and power station. The most difficult and important factors in the design of double-reheat boiler are the layout of heating surface and the steam temperature regulation method. Therefore, this work summarizes the arrangement of heating surface and temperature regulation method of existing double-reheat boiler in China. It is hoped that the work will set a benchmark for the development of double-reheat boiler and the future 700 °C power generation unit in the world.

LncRNA LINC00665 Promotes Ovarian Cancer Cell Proliferation and Inhibits Apoptosis via Targeting MiR-181a-5p/FHDC

Objective: Previous reports indicate that long intergenic non-coding RNA LINC00665 naturally occurred vital effect in various cancers. Herein, the role of LINC00665 in ovarian cancer progress was explored.Methods: We found that LINC00665 was upregulated in ovarian cancer cell lines. Besides that, A series of assays including flow cytometry, wound-healing, Transwell, Cell Counting Kit-8 (CCK-8), and EdU assay confirmed that the knockdown of LINC00665 could reduce the viability, proliferation and migration of SKOV-3 and OVCAR-3 cells. Accumulating evidence indicates that many lncRNAs can function as endogenous miRNA sponges by competitively binding common miRNAs. In this study, the bioinformatics analysis suggested that LNC00665 specifically binds to miR-181a-5p.Results: LINC00665 downregulated the miR-181a-5p in SKOV-3 and OVCAR-3 cells. The knockdown of miR-181a-5p evidently reverses the inhibitory effect of sh-LINC00662. Besides, FH2 Domain Containing 1 (FHDC1) has been proved to deed as an effective target of miR-181a-5p.Conclusion: Our results reveal the knockdown of LINC00665 facilitates ovarian cancer via development by sponging miR-181a-5p and upregulating FHDC1 expression; these may contribute to ovarian cancer therapy.

Degradation efficiencies of 2,4,6-TCP by Fe0-based advanced oxidation processes (AOPs) with common peroxides

Degradation of 2,4,6-trichlorophenol (2,4,6-TCP) by zero-valent iron (ZVI) activating three common peroxides (peroxymonosulfate (PMS), hydrogen peroxide (H2O2), and peroxydisulfate (PS)) was investigated. The effects of ZVI dosage, peroxides concentration, initial pH, and Cl- concentration were examined. The 2,4,6-TCP degradation efficiencies by Fe0/peroxides (PMS, H2O2, PS) were compared. Results showed that the order for degradation efficiency was H2O2≥PMS>PS. The degradation efficiency of 2,4,6-TCP in ZVI/peroxides systems were optimal at c(Ox) = 1 mmol•L-1; c(Fe0) = 0.1 g/L; initial pH = 3.2. Additionally, pH had a vital effect on 2,4,6-TCP degradation. At pH<3.2, ferrous play a vital role in all reaction, and accelerate the reaction rate rapidly. The existence of NaCl showed different results in the four systems. Chloride had little effect on 2,4,6-TCP degradation when chloride concentration at 5 mM, whereas the presence of 300 mM chloride significantly accelerated the degradation of 2,4,6-TCP from 72.7% to 95.2% in ZVI-PMS system. Notably, the other three systems showed opposite results. In contrast, the AOX (Absorbable Organic Halogen) values were highest in ZVI-PMS-Cl- system, due to the formation of lots of refractory chlorinated phenols as identified by GC-MS. These findings are good for choosing the most suitable technology for chlorophenol wastewater treatment.

Study on performance of thrust disk as auxiliary impeller

Thrust disk as auxiliary impeller has a vital effect on the big power pump unit with wet motor. It can balance the axial force of the unit, provide power for internal cooling circulation circuit of motor, and further reduce the axial length of the unit. Due to the motor chamber space is limited, and the transmission medium is liquid which needs to consider the effect of cavitation, the research of thrust disk of auxiliary impeller is different from the previous studies of rotating channel. In this paper, the hydraulic performance and cavitation characteristics of thrust disk as auxiliary impeller are investigated experimentally under different conditions. A thrust disk test rig was established to obtain data under different rotation speeds and flow points. Three types of volutes with different outlet angles were designed to match the thrust disk as auxiliary impeller in experiments. Results indicate that the law of speed proportion for the traditional centrifugal pump is not applicable to the head of thrust disk as auxiliary impeller. In addition, the flow coverage increases slightly with rotation speed. Furthermore, the higher the speed is, the larger the NPSHs is, and the narrower the range of NPSH is. Besides, the smaller the outlet angle is, the higher the head of the thrust disk as auxiliary impeller is, the worse anti-cavitation performance is. The research could provide reference and guidance for the design of thrust disk as auxiliary impeller.

LncRNA LINC00665 promotes ovarian cancer cell proliferation and inhibits apoptosis via targeting miR-181a-5p/FHDC

Previous reports indicate that LINC00665, a lincRNA, which is a naturally occurring long intergenic non-coding RNA exerts vital effect in a variety of cancers. Herein, we explore the role of LINC00665 in ovarian cancer. RT-qPCR was taken into the experiment to determine the expression level of LINC00665. Cell Counting Kit-8 (CCK-8), flow cytometry, wound healing, transwell, and EdU are employed to evaluate the effect of LINC00665 on cell proliferation, apoptosis, and migration in SKOV-3 and OVCAR-3 cells. The axis of LINC00665 and its specific miRNA, the miRNA target gene is explored in dual-luciferase reporter assay. Firstly, we find that LINC00665 is upregulated in ovarian cancer cell lines. Furthermore, not only the cell viability and in SKOV-3 and OVCAR-3 was reduced by LINC00665 knockdown but also cell proliferation and migration were inhibited. Afterwards, the bioinformatics analysis suggested that LNC00665 specifically binds to miR-181a-5p. Then, several studies confirmed that LINC00665 downregulated the miR-181a-5p in SKOV-3 and OVCAR-3 cells. The knockdown of miR-181a-5p evidently reverses the inhibitory effect of sh-LINC00662. Besides, FH2 Domain Containing 1 (FHDC1) has been proved to deed as an effective target of miR-181a-5p. In conclusion, the knockdown of LINC00665 facilitates ovarian cancer via development by sponging miR-181a-5p and upregulating FHDC1 expression.

Needs Analysis of English Language for Geoscience Undergraduates of Bamyan University

The purpose of this investigation was to identify the English language needs of the students currently studying at the Geoscience faculty of Bamyan University in Afghanistan. Total number of 306 under-graduates of Geoscience students from the second and third-year classes took part in this investigation. The main tool for data collection was a student questionnaire used to evaluate learners’ perceptions and needs of the English language. The results of the study show that when students come to the University, the English language proficiencies are quite low. The finding of the research shows that 20 per cent of the students’ level are beginner, 30 per cent of the students’ level are in pre-intermediate, 30 per cent of them are intermediate level and 15 per cent of them are in the upper-intermediate level and 5 per cent of them are in advance level. And most of the students’ study English for academic purpose and for their future profession. Likewise, the students believe that their English language proficiency has a vital effect on their academic performance in content subjects. Furthermore, the current English language program and classroom resources do not fulfil their needs as they prefer to have a class with lots of activities or more student-centred. Moreover, a majority of the students were not satisfied with the amount of time allocated for English classes. In addition, the majority of the students believe that if we don’t know English well, we can’t find a handsomely paid job. It is hoped that the findings of this study would be the basis for designing a suitable course that would meet students’ needs. Keywords: Needs analysis, English language needs, language proficiency

Bacterial and abiogenic carbonates formed in caves–no vital effect on clumped isotope compositions

Speleothems (dominated by cave-hosted carbonate deposits) are valuable archives of paleoclimate conditions. As such, they are potential targets of clumped isotope analyses that may yield quantified data about past temperature variations. Clumped isotope analyses of stalagmites, however, seldom provide useful temperature values due to various isotope fractionation processes. This study focuses on the determination of the microbially induced vital effect, i.e., the isotope fractionation processes related to bacterial carbonate production. A cave site with biologically mediated amorphous calcium carbonate precitation was selected as a natural laboratory. Calcite deposits were farmed under a UV lamp to prevent bacterial activity, as well as under control conditions. Microbiological analyses and morphological investigations using scanning electron microscopy showed that the UV lamp treatment effectively reduced the number of bacterial cells, and that bacterial carbonate production strongly influenced the carbonate’s morphology. Stable oxygen isotope analyses of calcite and drip waters, as well as clumped isotope measurements revealed that, although most of the studied carbonates formed close to oxygen isotope equilibrium, clumped isotope Δ47 values varied widely from equilibrium to strongly fractionated data. Site-specific kinetic fractionations played a dominant role in the distribution of Δ47 values, whereas bacterial carbonate production did not result in a detectable clumped isotope effect.

Threshold dynamics of a general delayed HIV model with double transmission modes and latent viral infection

<abstract><p>In this paper, a general HIV model incorporating intracellular time delay is investigated. Taking the latent virus infection, both virus-to-cell and cell-to-cell transmissions into consideration, the model exhibits threshold dynamics with respect to the basic reproduction number $ \mathfrak{R}_0 $. If $ \mathfrak{R}_0 &lt; 1 $, then there exists a unique infection-free equilibrium $ E_0 $, which is globally asymptotically stable. If $ \mathfrak{R}_0 &gt; 1 $, then there exists $ E_0 $ and a globally asymptotically stable infected equilibrium $ E^* $. When $ \mathfrak{R}_0 = 1 $, $ E_0 $ is linearly neutrally stable and a forward bifurcation takes place without time delay around $ \mathfrak{R}_0 = 1 $. The theoretical results and corresponding numerical simulations show that the existence of latently infected cells and the intracellular time delay have vital effect on the global dynamics of the general virus model.</p></abstract>

The role of estrogen receptor beta in breast cancer

Breast cancer, a malignant tumor originating from mammary epithelial tissue, is the most common cancer among women worldwide. Challenges facing the diagnosis and treatment of breast cancer necessitate the search for new mechanisms and drugs to improve outcomes. Estrogen receptor (ER) is considered to be important for determining the diagnosis and treatment strategy. The discovery of the second estrogen receptor, ERβ, provides an opportunity to understand estrogen action. The emergence of ERβ can be traced back to 1996. Over the past 20 years, an increasing body of evidence has implicated the vital effect of ERβ in breast cancer. Although there is controversy among scholars, ERβ is generally thought to have antiproliferative effects in disease progression. This review summarizes available evidence regarding the involvement of ERβ in the clinical treatment and prognosis of breast cancer and describes signaling pathways associated with ERβ. We hope to highlight the potential of ERβ as a therapeutic target.