691 research outputs found
Analytical study of the velocity of the lubricating fluid in the hydrodynamic journal bearing with the effect of centrifugal force for short bearing type
The paper aims to obtain the expression of the velocity of lubricating fluid in the hydrodynamic journal bearings by analytical method. In the classical short-bearing theory, the fluid flow was studied by ignoring the effect of centrifugal force of the lubricating fluid film. However, the self-oscillation of the shaft of high-power motors does not follow the rules in classical hydrodynamic lubrication theory. To explain this phenomenon, a modified form of Reynolds equation, in which the influence of centrifugal force of the lubricant is not ignored, is established. The study aims to establish the modified Reynolds equation by including the effect of centrifugal forces for the case of the short bearing type. Integration of the Navier-Stokes equations, yield the expressions for the components of velocity of the lubricating fluid in the gap. The oil’s pressure in the hydrodynamic journal bearing is obtained by solving the modified Reynolds equation. The numerical results are considered in the case of the stable equilibrium position of the motion of the shaft, i.e. the symmetry axis of the shaft does not move. The plots of the velocity components in the tangential axial direction are displayed too. The theoretical results of a parabolic velocity distribution similar to that of a Newtonian fluid, derived from a Bingham plastic flow model. The flow in the gap, which are obtained by analytical method, are completely consistent with its boundary conditions and its physical properties. Further, with these results, the paper as a lemma to solve the dynamics problem in floating ring bearing with the influence of the centrifugal force of the lubrican
Incidences between points and generalized spheres over finite fields and related problems
Let be a finite field of elements where is a large odd
prime power and , where , , and for all . A -sphere is a set of the form , where . We prove bounds on the number of incidences between a point set
and a -sphere set , denoted by
, as the following.
We prove this estimate by studying the spectra of directed graphs. We also
give a version of this estimate over finite rings where is
an odd integer. As a consequence of the above bounds, we give an estimate for
the pinned distance problem. In Sections and , we prove a bound on the
number of incidences between a random point set and a random -sphere set in
. We also study the finite field analogues of some
combinatorial geometry problems, namely, the number of generalized isosceles
triangles, and the existence of a large subset without repeated generalized
distances.Comment: to appear in Forum Mat
Reclamation of Marine Chitinous Materials for Chitosanase Production via Microbial Conversion by Paenibacillus macerans
[[abstract]]: Chitinous materials from marine byproducts elicit great interest among biotechnologists for
their potential biomedical or agricultural applications. In this study, four kinds of marine chitinous
materials (squid pens, shrimp heads, demineralized shrimp shells, and demineralized crab shells)
were used to screen the best source for producing chitosanase by Paenibacillus macerans TKU029.
Among them, the chitosanase activity was found to be highest in the culture using the medium
containing squid pens as the sole carbon/nitrogen (C/N) source. A chitosanase which showed
molecular weights at 63 kDa was isolated from P. macerans cultured on a squid pens medium.
The purified TKU029 chitosanase exhibited optimum activity at 60 ◦C and pH 7, and was stable at
temperatures under 50 ◦C and pH 3-8. An analysis by MALDI-TOF MS revealed that the chitosan
oligosaccharides (COS) obtained from the hydrolysis of water-soluble chitosan by TKU029 crude
enzyme showed various degrees of polymerization (DP), varying from 3–6. The obtained COS
enhanced the growth of four lactic acid bacteria strains but exhibited no effect on the growth of E. coli.
By specialized growth enhancing effects, the COS produced from hydrolyzing water soluble chitosan
with TKU029 chitinolytic enzymes could have potential for use in medicine or nutraceuticals.[[sponsorship]]MOST[[notice]]補正完
Teachers’ perception of the necessity of applying online applications for organizing teaching activities at high school in Vietnam
E-learning has gained popularity as a method of delivering education recently and offers many advantages to enhance the learning experience for students. Technology allows teachers to design more interactive and engaging lessons that cater to different learning styles. It can also provide opportunities for teachers to incorporate virtual simulations and real-time data which can help students better understand complex concepts. The total number of survey samples was 187 teachers. Awareness of the need and purpose of applying information literacy in the organization of teaching activities was created to analyze. The results of the findings were interpreted in three ways: (i) Self-assessment of teachers’ competence in applying technology in organizing teaching activities. (ii) Awareness of the necessity of using online applications in organizing teaching activities in schools. (iii) Awareness of the goal of using online applications in the organization of teaching activities. Based on the results of the current study, the article establishes the process of applying online applications in the organization of teaching activities and proposes recommendations for subjects directly related to the application of online applications. High school administrators, teachers and educational management agencies at all levels are using online innovation to organize teaching activities in high schools
Link Prediction for Wikipedia Articles as a Natural Language Inference Task
Link prediction task is vital to automatically understanding the structure of
large knowledge bases. In this paper, we present our system to solve this task
at the Data Science and Advanced Analytics 2023 Competition "Efficient and
Effective Link Prediction" (DSAA-2023 Competition) with a corpus containing
948,233 training and 238,265 for public testing. This paper introduces an
approach to link prediction in Wikipedia articles by formulating it as a
natural language inference (NLI) task. Drawing inspiration from recent
advancements in natural language processing and understanding, we cast link
prediction as an NLI task, wherein the presence of a link between two articles
is treated as a premise, and the task is to determine whether this premise
holds based on the information presented in the articles. We implemented our
system based on the Sentence Pair Classification for Link Prediction for the
Wikipedia Articles task. Our system achieved 0.99996 Macro F1-score and 1.00000
Macro F1-score for the public and private test sets, respectively. Our team
UIT-NLP ranked 3rd in performance on the private test set, equal to the scores
of the first and second places. Our code is publicly for research purposes.Comment: Accepted at the 10th IEEE International Conference On Data Science
And Advanced Analytics (DSAA 2023
SUMO-SPECIFIC PROTEASE 1 CONTROLS LYMPHOID DEVELOPMENT THROUGH REGULATION OF SUMOYLATION/ACETYLATION SWITCH IN STAT5
SUMOylation has emerged as an important regulatory mechanism for protein function. SUMO-specific proteases (SENPs) are essential for removing SUMO from conjugated proteins in many different systems, but the physiological functions of SENPs are poorly understood. STAT5 (Signal Transducer and Activator of Transcription 5) plays a critical role in the development of lymphoid cells. However, it is not known whether STAT5 is regulated by the SUMOylation pathway. Here, we showed that SUMOylated STAT5 is accumulated in SENP1-/- lymphoid precursors. SENP1 deficiency results in severe defects in early T and B cell development, similar to that observed in mice harboring a complete inactivation of STAT5. Because STAT5 is SUMOylated and acetylated at the same lysine residue, SENP1 deficiency blocks STAT5 in the SUMOylation state, resulting in diminished STAT5 acetylation and phosphorylation, and defective lymphoid development. Thus, our results reveal a novel function of SENP1 in the regulation of early lymphoid development via an acetylation/SUMOylation switch in STAT5
Avoid Deadlock Resource Allocation (ADRA) Model V VM-out-of-N PM: Avoid Deadlock Resource Allocation (ADRA) Model V VM-out-of-N PM
This paper presents an avoid deadlock resource allocation (ADRA) for model V VM-out-of-N PM since cloud computing is a new computing paradigm composed of grid computing, distributed computing and utility concepts. Cloud computing presents a different resource allocation paradigm than either grids or distributed systems. Cloud service providers dynamically scale virtualized computing resources as a service over the internet. Due to variable number of users and limited resources, cloud is prone to deadlock at very large scale. Resource allocation and the associated deadlock avoidance is problem originated in the design and the implementation of the distributed computing, grid computing. In this paper, a new concept of free space cloud is proposed to avoid deadlock by collecting available free resource from all allocated users. New algorithms are developed for allocating multiple resources to competing services running in virtual machines on a heterogeneous distributed platform. An experiment is tested in CloudSim. The performance of resource pool manager is evaluated by using CloudSim and resource utilization and indicating good results
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