An Improvement to Holospectrum Based Field Balancing Method by Reselection of Balancing Object

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Yuhe Liao ◽  
Genfeng Lang ◽  
Fangji Wu ◽  
Liangsheng Qu
Keyword(s):  
Initial Phase ◽  
Computational Procedure ◽  
Field Application ◽  
Phase Vector ◽  
Unbalanced Rotor ◽  
Balance State ◽  
Probe Orientation ◽  
Rotor Balance ◽  
The Impact ◽  
Anisotropic Stiffness

In this paper, the holospectrum technique based balancing method has been improved by reselection of the balancing object. Current holospectrum based balancing technique uses the initial phase vector (IPV) as the balancing object. Theoretical analysis of the precession behavior of an unbalanced rotor with anisotropic stiffness shows that, compared with the IPV, its forward precession component vector is much better in describing the rotor balance state and is more suitable to be used as the measurement of unbalance response. After the backward precession component is removed, the impact of probe orientation on the balancing analysis and calculation is completely eliminated and the computational procedure is greatly simplified without sacrificing the balancing precision. The experiments and field application cases verify the accuracy and effectiveness of this method.

An improved holospectrum-based balancing method for rotor systems with anisotropic stiffness

2012 ◽  
Vol 227 (2) ◽  
pp. 246-260 ◽  
Author(s):  
Yun Zhang ◽  
Xuesong Mei ◽  
Mingping Shao ◽  
Muxun Xu
Keyword(s):  
Initial Phase ◽  
Initial Conditions ◽  
Empirical Test ◽  
Negative Influence ◽  
Theoretical Expression ◽  
Phase Vector ◽  
Rotor Systems ◽  
Unbalanced Rotor ◽  
Scope Of Application ◽  
Anisotropic Stiffness

As a ubiquitous phenomenon in rotor systems, anisotropic stiffness generally causes the response of an unbalanced rotor to vary across radial directions. The standard holospectrum-based balancing method, which adopts the initial phase vector as a balancing object, cannot be used in rotor systems with anisotropic stiffness. To tackle the limitations of the standard holospectrum-based balancing method, an improved holospectrum-based balancing method with increased accuracy and a greater scope of application is presented in this article. First, a dynamic model of an unbalanced rotor system with anisotropic stiffness is developed, the theoretical expression of the deviation between the initial phase vector and the unbalance is examined, and the effects of anisotropic stiffness on the initial phase vector are analysed. Second, based on the analysis of the precession characteristics of the rotor, a modified initial phase vector that compensates for the negative influence of anisotropic stiffness is presented as the new balancing object. An improved holospectrum-based balancing method is proposed based on this modified initial phase vector, and the balancing procedures are summarised in detail. Finally, the initial phase vector induced error in the identification of the unbalance is simulated for different initial conditions, and the feasibility of the modified initial phase vector is verified on a rotor test rig. Both the numerical analysis and the empirical test validate the effectiveness and accuracy of this new method.

scholarly journals The Impact and Implications of The COVID-19 Pandemic on Organ Procurement Outside of an Epicenter

2021 ◽  
pp. 152692482110028
Author(s):  
Janice Jene Hudgins ◽  
Allison Jo Boyer ◽  
Kristen Danielle Orr ◽  
Clint Allen Hostetler ◽  
Jeffrey Paul Orlowski ◽  
...  
Keyword(s):  
Health Care ◽  
Initial Phase ◽  
Organ Procurement ◽  
Health Care Systems ◽  
Health Data ◽  
Organ Procurement Organization ◽  
Care Systems ◽  
The Impact ◽  
Variable Impact ◽  
Single Organ

The COVID-19 pandemic has been well-documented to have a variable impact on individual communities and health care systems. We describe the experience of a single organ procurement organization (OPO), located in an area without a large cluster of cases during the initial phase of the COVID-19 pandemic. A review of community health data describing the impact of COVID-19 nationally and in Oklahoma was conducted. Additionally, a retrospective review of available OPO data from March 2019-May 2020 was performed. While the amount of donor referrals received and organs recovered by the OPO remained stable in the initial months of the pandemic, the observed organs transplanted vs. expected organs transplanted (O:E) decreased to the lowest number in the 15-month period and organs transplanted decreased as well. Fewer organs from Oklahoma donors were accepted for transplant despite staff spending more time allocating organs.

scholarly journals OP0244 A PRECLINICAL TESTING TOOL: THE IN VITRO 3D FRACTURE GAP MODEL

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 154.1-154
Author(s):  
M. Pfeiffenberger ◽  
A. Damerau ◽  
P. Hoff ◽  
A. Lang ◽  
F. Buttgereit ◽  
...  
Keyword(s):  
Fracture Healing ◽  
Bone Healing ◽  
Inflammatory Markers ◽  
Initial Phase ◽  
Gap Model ◽  
Osteogenic Markers ◽  
Immunosuppressed Patients ◽  
The Impact

Background:Approximately 10% of fractures lead to significant fracture healing disorders, with a tendency to further increase due to the aging population. Of note, especially immunosuppressed patients with ongoing inflammation show difficulties in the correct course of fracture healing leading to fracture healing disorders. Most notably, invading immune cells and secreted cytokines are considered to provide an inflammatory microenvironment within the fracture gap, primarily during the initial phase of fracture healing. Current research has the focus on small animal models, facing the problem of translation towards the human system. In order to improve the therapy of fracture healing disorders, we have developed a human cell-basedin vitromodel to mimic the initial phase of fracture healing adequately. This model will be used for the development of new therapeutic strategies.Objectives:Our aim is to develop anin vitro3D fracture gap model (FG model) which mimics thein vivosituation in order to provide a reliable preclinical test system for fracture healing disorders.Methods:To assemble our FG model, we co-cultivated coagulated peripheral blood and primary human mesenchymal stromal cells (MSCs) mimicking the fracture hematoma (FH model) together with a scaffold-free bone-like construct mimicking the bony part of the fracture gap for 48 h under hypoxic conditions (n=3), in order to reflect thein vivosituation after fracture most adequately. To analyze the impact of the bone-like construct on thein vitroFH model with regard to its osteogenic induction capacity, we cultivated the fracture gap models in either medium with or without osteogenic supplements. To analyze the impact of Deferoxamine (DFO, known to foster fracture healing) on the FG model, we further treated our FG models with either 250 µmol DFO or left them untreated. After incubation and subsequent preparation of the fracture hematomas, we evaluated gene expression of osteogenic (RUNX2,SPP1), angiogenic (VEGF,IL8), inflammatory markers (IL6,IL8) and markers for the adaptation towards hypoxia (LDHA,PGK1) as well as secretion of cytokines/chemokines using quantitative PCR and multiplex suspension assay, respectively.Results:We found via histology that both the fracture hematoma model and the bone-like construct had close contact during the incubation, allowing the cells to interact with each other through direct cell-cell contact, signal molecules or metabolites. Additionally, we could show that the bone-like constructs induced the upregulation of osteogenic markers (RUNX2, SPP1) within the FH models irrespective of the supplementation of osteogenic supplements. Furthermore, we observed an upregulation of hypoxia-related, angiogenic and osteogenic markers (RUNX2,SPP1) under the influence of DFO, and the downregulation of inflammatory markers (IL6,IL8) as compared to the untreated control. The latter was also confirmed on protein level (e.g. IL-6 and IL-8). Within the bone-like constructs, we observed an upregulation of angiogenic markers (RNA-expression ofVEGF,IL8), even more pronounced under the treatment of DFO.Conclusion:In summary, our findings demonstrate that our establishedin vitroFG model provides all osteogenic cues to induce the initial bone healing process, which could be enhanced by the fracture-healing promoting substance DFO. Therefore, we conclude that our model is indeed able to mimic correctly the human fracture gap situation and is therefore suitable to study the influence and efficacy of potential therapeutics for the treatment of bone healing disorders in immunosuppressed patients with ongoing inflammation.Disclosure of Interests:Moritz Pfeiffenberger: None declared, Alexandra Damerau: None declared, Paula Hoff: None declared, Annemarie Lang: None declared, Frank Buttgereit Grant/research support from: Amgen, BMS, Celgene, Generic Assays, GSK, Hexal, Horizon, Lilly, medac, Mundipharma, Novartis, Pfizer, Roche, and Sanofi., Timo Gaber: None declared

Advances in Chinese research on Azolla

1985 ◽  
Vol 86 ◽  
pp. 161-167 ◽  
Author(s):  
Thomas A. Lumpkin
Keyword(s):  
Green Manure ◽  
Field Application ◽  
Symbiotic Relationship ◽  
Aquatic Fern ◽  
Communication Problems ◽  
The Impact

SynopsisThe aquatic fern Azolla has a symbiotic relationship with an N2-fixing cyanobacterium. Fanners in China and Vietnam have used Azolla for centuries as a green manure for rice and as fodder for pigs, ducks and fish. Chinese researchers have been studying Azolla since the early 1950's but many of their achievements are unknown outside China because of language and other communication problems. This article reviews current Chinese Azolla research and focuses on the impact of newly introduced Azolla species in the areas of field application, use of spores, and isolation of the N2-fixing symbiont.

Optimization and Investigation on the Impact of Centrifugal Impeller Blade Thickness Distribution on Hydro-Induced Vibration

2018 ◽  
Author(s):  
B. Qian ◽  
D. Z. Wu
Keyword(s):  
Secondary Flow ◽  
Thickness Distribution ◽  
Suction Side ◽  
Centrifugal Impeller ◽  
Impeller Blade ◽  
Streamwise Location ◽  
Unbalanced Rotor ◽  
Blade Thickness ◽  
Vibration Performance ◽  
The Impact

The vibration performance of centrifugal impellers is of great importance for pumps in some application areas such as automobiles and ships. Apart from mechanical excitations for instance, unbalanced rotor and misalignment, attentions should be concentrated on the hydraulic excitations. The complex internal secondary flow in the centrifugal impeller brings degradation on both hydraulic and vibration performances. On the purpose of repressing the internal secondary flow and alleviating vibration, an attempt of optimization by controlling the thickness distribution of centrifugal impeller blade is given. The vibration performances of the impellers are investigated numerically and experimentally. Meanwhile, further study on the mechanism of the influence of the thickness distribution optimization on vibration is conducted. There is a relative velocity gradient from suction side (SS) to pressure side (PS) due to the Coriolis force, which causes non-uniformity of energy distribution. By means of thickness distribution optimization, the impeller blade angle on the PS and SS along the blade-aligned (BA) streamwise location is respectively modified and therefore the flow field can be improved.

scholarly journals Ability of near-infrared spectroscopy and chemometrics to predict the age of mosquitoes reared under different conditions

2020 ◽  
Author(s):  
Oselyne Ong ◽  
Elise Kho ◽  
Pedro Esperança ◽  
Chris Freebairn ◽  
Floyd Dowell ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Field Application ◽  
Machine Learning Techniques ◽  
Island Population ◽  
Natural Environments ◽  
Pls Regression ◽  
Field Methods ◽  
The Impact

Abstract Background: Practical, field-ready age-grading tools for mosquito vectors of disease are urgently needed because of the impact that daily survival has on vectorial capacity. Previous studies have shown that near-infrared spectroscopy (NIRS), in combination with chemometrics and predictive modeling, can forecast the age of laboratory-reared mosquitoes with moderate to high accuracy. It remains unclear whether the technique has utility for identifying shifts in the age structure of wild-caught mosquitoes. Here we investigate whether models derived from the laboratory strain of mosquitoes can be used to predict the age of mosquitoes grown from pupae collected in the field. Methods: NIR spectra from adult female Aedes albopictus mosquitoes reared in the laboratory (2, 5, 8, 12 and 15 days old) were compared to spectra from mosquitoes emerging from wild-caught pupae (1, 7 and 14 days old). Different partial least squares (PLS) regression methods trained on spectra from laboratory mosquitoes were evaluated on their ability to predict the age of mosquitoes from more natural environments. Results: Models trained on spectra from laboratory-reared material were able to predict the age of other laboratory-reared mosquitoes with moderate accuracy and successfully differentiated all day 2 and 15 mosquitoes. Models derived with laboratory mosquitoes could not differentiate between field-derived age groups, with age predictions relatively indistinguishable for day 1-14. Pre-processing of spectral data and improving the PLS regression framework to avoid overfitting can increase accuracy, but predictions of mosquitoes reared in different environments remained poor. Principle component analysis confirms substantial spectral variations between laboratory and field-derived mosquitoes despite both originating from the same island population. Conclusions: Models trained on laboratory mosquitoes were able to predict ages of laboratory mosquitoes with good sensitivity and specificity though they were unable to predict age of field-derived mosquitoes. This study suggests that laboratory-reared mosquitoes do not capture enough environmental variation to accurately predict the age of the same species reared under different conditions. Further research is needed to explore alternative pre-processing methods and machine learning techniques, and to understand factors that affect absorbance in mosquitoes before field application using NIRS.

scholarly journals Vibrations attenuation of a system excited by unbalance and the ground movement by an impact element

2016 ◽  
Vol 1 (2) ◽  
pp. 603-616 ◽  
Author(s):  
Marek Lampart ◽  
Jaroslav Zapoměl
Keyword(s):  
Differential Equations ◽  
Research Work ◽  
Computational Procedure ◽  
Ground Movement ◽  
Frequency Interval ◽  
Nonlinear Behaviour ◽  
Helical Springs ◽  
Impact Element ◽  
The Individual ◽  
The Impact

AbstractThis paper concentrates on the vibrations attenuation of a rotor driven by a DC motor and its frame flexibly coupled with a baseplate by linear cylindrical helical springs and damped by an element that can work either in inertia or impact regime. The system oscillation is governed by three mutually coupled second-order ordinary differential equations. The nonlinear behaviour occurs if the impact regime is adjusted. The damping element operating in inertia mode reduces efficiently the oscillations amplitude only in a narrow frequency interval. In contrast, the damping device working in impact regime attenuates vibrations of the rotor frame in a wider range of the excitation frequencies and it can be easily extended if the clearances between the rotor casing and the damping element are controlled. The development of a computational procedure for investigation of vibration of a flexibly supported rotor and for its attenuation by the inertia and impact dampers; learning more on efficiency of the individual damping regimes; finding possibilities of extension of the frequency intervals of applicability of the damping device; and obtaining more information on the character of the vibration induced by impacts are the main contributions of this research work.

scholarly journals Language loyalty and ethnolinguistic solidarity of members of the Slovak language community in Vojvodina

2017 ◽  
Vol 73 (1-2) ◽  
pp. 155-169
Author(s):  
Dalibor Sokolovic
Keyword(s):  
Initial Phase ◽  
Language Attitudes ◽  
Essential Element ◽  
Language Community ◽  
Linguistic Description ◽  
The Impact ◽  
Slovak Language ◽  
Insight Into ◽  
Important Constituent

This paper analyses the impact of linguistic loyalty and solidarity on the preservation of the Slovak language community in Vojvodina. These factors represent an essential element in the model of linguistic description of a language community in a minority position. In the first part of the paper, we present the structure and components of ethnolinguistic solidarity of the Slovak community in Vojvodina, and in the second we show results of the survey conducted in 2014 among members of the community related to the level of their linguistic loyalty. Language attitudes of members of the Slovak language community in Vojvodina presented in this analysis bring us new insight into the structure of ethnolinguistic solidarity and reveal the reasons and motivation of their linguistic loyalty, or the absence of it. Vojvodinian Slovaks consider their own language as the most important constituent of their ethnicity, but the survey nonetheless also identified characteristics of the initial phase of the process of language relativisation, as well as a reduction of its role as the cultural marker of the community.

scholarly journals Discrete Time Ruin Probability for Takaful (Islamic Insurance) with Investment and Qard-Hasan (Benevolent Loan) Activities

2020 ◽  
Vol 13 (9) ◽  
pp. 211 ◽  
Author(s):  
Dila Puspita ◽  
Adam Kolkiewicz ◽  
Ken Seng Tan
Keyword(s):  
Business Model ◽  
Ruin Probability ◽  
Risk Model ◽  
Computational Procedure ◽  
Profit Sharing ◽  
Probability Of Ruin ◽  
Agent Based ◽  
Key Variables ◽  
Islamic Insurance ◽  
The Impact

The main objectives of this paper are to construct a new risk model for modelling the Hybrid-Takaful (Islamic Insurance) and to develop a computational procedure for calculating the associated ruin probability. Ruin probability is an important study in actuarial science to measure the level of solvency adequacy of an insurance product. The Hybrid-Takaful business model applies a Wakalah (agent based) contract for underwriting activities and Mudharabah (profit sharing) contract for investment activities. We consider the existence of qard-hasan facility provided by the operator (shareholder) as a benevolent loan for the participants’ fund in case of a deficit. This facility is a no-interest loan that will be repaid if the business generates profit in the future. For better investment management, we propose a separate investment account of the participants’ fund. We implement several numerical examples to analyze the impact of some key variables on the Takaful business model. We also find that our proposed Takaful model has a better performance than the conventional counterpart in terms of the probability of ruin.

Predicting Annual Heating Demand under Sensitivity Analysis

2013 ◽  
Vol 330 ◽  
pp. 911-915 ◽  
Author(s):  
Vladimír Geletka ◽  
Anna Sedláková
Keyword(s):  
Sensitivity Analysis ◽  
Performance Feedback ◽  
Initial Phase ◽  
Architectural Design ◽  
Building Design ◽  
Stochastic Approach ◽  
Energy Performance ◽  
Simulation Based ◽  
Input Parameters ◽  
The Impact

The quality of most buildings may be affected during the initial phase of architectural design. It is therefore to optimize input parameters, which significantly influence energy efficiency. In principle it is possible to speak of a deterministic approach, which consider the input parameters to be fixed or a stochastic approach, which takes a wider set of input parameters into account. A single-storey house is evaluated in terms of energy performance in the initial phase of building design, where input parameters are changed in order to determine a correlation coefficient. The methodology is based on a sensitivity analysis (SA) and MonteCarlo simulation based on a stochastic random selection. Regression (RA) were written to express the impact architectural design has on energy performance. Feedback from the regression model estimates annual heating demand of single storey house.

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