Impact Of Centrifugal Force Research Articles

The Impact of Centrifugal Force on Isolation of Bone Marrow Mononuclear Cells Using Density Gradient Centrifugation.

Bone marrow mononuclear cells (BMMNCs) have great potential in bone regenerative therapy. The main method used today to obtain BMMNCs is Ficoll density gradient centrifugation. However, the centrifugal force for this isolation method is still suboptimal. To determine the optimal centrifugal force in Ficoll density gradient centrifugation of bone marrow (BM) to achieve high stem/progenitor cell content BMMNCs for regenerative therapy. BM was aspirated from nine minipigs and divided into three groups according to different centrifugal forces (200g, 300g and 400g). Immediately after BMMNCs were obtained from each group by Ficoll density gradient centrifugation, residual red blood cell (RBC) level, nucleated cell counting, viability and flow cytometric analyses of apoptosis and reactive oxygen species (ROS) generation were measured. The phenotypic CD90 and colony formation analyses of BMMNCs of each group were performed as well. Bone marrow-derived mesenchymal stem cells (BMSCs) were harvested at passage 2, then morphology, cell phenotype, proliferation, adipogenic, chondrogenic and osteogenic lineage differentiation potential of BMSCs from each group were compared. The 300g centrifugal force was able to isolate BMMNCs from BM with the same efficiency as 400g and provided significantly higher yields of CD90+ BMSCs and fibroblastic colony-forming units of BMSC (CFU-f(BMSC)), which is more crucial for the regenerative efficacy of BMMNCs. Meanwhile, 200g hosted the most RBC contamination and minimum CFU-f (BMSC) yield, which will be disadvantageous for BMMNC-based cell therapy. As for in vitro cultured BMSCs which were isolated from BMMNCs by different centrifugal forces, no significant differences were found on morphology, cell proliferation rate, phenotypic marker, adipogenic, chondrogenic and osteogenic differentiation potential. 300g may be the optimal centrifugal force when using Ficoll density gradient centrifugation to isolate BMMNCs for bone regenerative therapy. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Aircraft Propeller Design through Constrained Aero-Structural Particle Swarm Optimization

An aero-structural algorithm to reduce the energy consumption of a propeller-driven aircraft is developed through a propeller design method coupled with a Particle Swarm Optimization (PSO). A wide range of propeller parameters is considered in the optimization, including the geometry of the airfoil at each propeller section. The propeller performance prediction tool employs a convergence improved Blade Element Momentum Theory fed by airfoil aerodynamic characteristics obtained from XFOIL and a validated OpenFOAM. A stall angle correction is estimated from experimental NACA 4-digits data and employed where convergence issues emerge. The aerodynamic data are corrected to account for compressibility, three-dimensional, viscous, and Reynolds number effects. The coefficients for the rotational corrections are proposed from experimental data fitting. A structural model based on Euler-Bernoulli beam theory is employed and validated against Finite Element Analysis, while the impact of centrifugal forces is discussed. A case of study is carried out where the chord and pitch distributions are compared to minimal losses distribution from vortex theory. Wind tunnel tests were performed with printed propellers to conclude the feasibility of the entire routine and the differences between XFOIL and CFD optimal propellers. Finally, the optimal CFD propeller is compared against a commercial propeller with the same diameter, pitch, and operational conditions, showing higher thrust and efficiency.

ИССЛЕДОВАНИЯ ВЛИЯНИЯ ТЕХНОЛОГИЧЕСКИХ ПАРАМЕТРОВ НА ФОРМИРОВАНИЯ КАЧЕСТВА ПОВЕРХНОСТНОГО СЛОЯ ДЕТАЛЕЙ ПРИ ЦЕНТРОБЕЖНО РОТАЦИОННОЙ ОБРАБОТКЕ

In the paper there are carried out investigations on the definition of the basic technological parameters impact of centrifugal-rotary processing in abrasive environment upon formation of surface layer quality in the parts worked. 
 There is used a finite element method of deformation modeling in granulated massive rotating under the impact of centrifugal forces with the use of the (Comsol Multiphysics) packet. On the basis of computer the high-speed shooting processing and theoretical investigations of the process dynamics there are defined distributions of pressures and granule motion speed in the working chamber. 
 A specified model of abrasive granule encounter with the surface worked at the centrifugal rotary processing on the basis of the modern researches and analysis with the use of the Ansys software. 
 The dependences are obtained for the definition of the maximum penetration depth of environment particles into the surface of the part worked, metal removal, surface roughness which adequacy is confirmed by the results of experimental investigations. There is developed a specified procedure for the computation of roughness height parameters of the surface worked and machining capacity. A specified procedure for the computation of metal removal from the surface worked of parts is offered. An algorithm for the optimization of an engineering process is developed. The investigation results are introduced into production.

Investigation of the psychophysiological response of passengers of fast trains with the different comfort level

Introduction. To create a regulatory framework, including harmonized with European normative documents in terms of assessing passengers’ comfort, the standard of the enterprise STO RZD “Services in railway transport was developed. Rules for assessing the level of comfort of passengers on trains.” The objective of the study is to compare the indices of the comfort level of passengers, determined by the values of the accelerations acting on them, with the psychological sensations and physiological changes in the body arising in this case, depending on the rolling stock and the state of the track. Material and methods. The experiment using ECG monitoring devices was carried out in four groups of eleven people, six men and five women aged 30-55 years. Additionally, in each group, a psychological survey of 11 more passengers was carried out. All of them were staff members of the Russian Railways divisions. Results. When traveling on high-speed trains “Lastochka” and “Sapsan,” the respondents more often note drowsiness and an exhausted state’s progression. At the end of the trip, they often emphasize stiffness, discomfort, numbness, and numbness of the leg muscles, probably associated with an extended stay in a forced position in the absence of specific freedom movements. In the “lying” position, a person experiences less fatigue, which, according to the sensations, hardly differs from the conditions of a trip in a “sitting” position during short journeys. Regulatory changes in the cardiovascular system are manifested with the combined influence of uncanceled accelerations (the impact of centrifugal forces) and movement speed changes. Conclusion. Carrying out a questionnaire survey and physiological measurements of the dynamics of heart rate fluctuations on the investigated sections of the routes in combination with the obtained technical data on the nature of mobile rail vehicles’ movement confirm the absence of critical discomfort for passengers when traveling on passenger and high-speed trains. The calculated values of the average and constant comfort levels are consistent and do not require correction of the corresponding scales’ values.

Discovering and Modelling the Wave-Like Shapes on the Surface of Metal Deposits, being Electrodeposited under the Force Impact

The further evidence is presented for the phenomenon existence of the electrochemical phase formation of metals and alloys through the stage of the overcooled liquid state. An idea is proposed about the possible occurrence of wave-like shapes on the surface of metal deposits, electrodepositing under weak force impact. First it was predicted and then revealed experimentally, a wave-like vibration of a solidifying surface of the metal being electrodeposited in the form of ripples or choppiness under the weak force impact in parallel to the crystallization front. A mathematical model has been obtained describing the liquid state behaviour of metals being electrodeposited under the impact of centrifugal force on the annular plate. The generalized Maxwell model was used as the basic rheological equation of a state. The difference between the results obtained is testified when considering Newtonian and non-Newtonian (power-law) liquid. The software blocks for solving the obtained mathematical model, based on the MathCAD package, have been developed.

Method of Appraising Adhesion Properties of Lubricants

A new method of quantitative appraisal of adhesion properties of lubricants and their dispersion media, which is based on determination of the forces of adherence between the lubricant and the metallic surface as well as between the elements of the structural framework of the lubricant under the destructive impact of centrifugal force, is described. The results of the investigation on the influence of the base oil type and the nature of the thickener on the adhesion properties of the lubricants are reported.

Primary recovery of alkaline phosphatase from hepatopancreatic tissues of Indian white shrimp at varied centrifugal force and time

Hepatopancreatic tissues of Indian white shrimp (Penaeus indicus) homogenate was centrifuged at relative centrifugal force (RCF) of 67.2, 1,681.1, 6,724.3, 15,124.8, or 26,897.4×g for 5, 10, 15, or 20 min at 4°C. Impact of centrifugal force and time on the primary clarification and alkaline phosphatase activity of the homogenate was determined by the proportionate at which solids, proteins, lipids, and alkaline phosphatase fractioned inbetween supernatant, infranatant, and pellets. Optimum yield of the enzyme achieved at RCF of 1,681.1×g for 5 min at 4°C was 90.28±1.55%. The forces below this level even upto 20 min removed only up to 56.57±0.66% of the total solids and 7.90±0.19% of the total lipids from the homogenate. At the force and time above RCF of 1,681.1×g and 5 min, specific activity was increased by 4.18±0.38-fold due to the loss of total protein, but upto 60.48±2.61% of alkaline phosphatase activity was lost.

A Preliminary Investigation into the Impact of Centrifugal Forces and Cake Properties on Methanogenesis from Dewatered Sludge Cake

A Preliminary Investigation into the Impact of Centrifugal Forces and Cake Properties on Methanogenesis from Dewatered Sludge Cake

Russia as a Security Disaster Area: Possible Conflicts and Interventions in 2015

Abstract The fluid state of the system of international relations in the middle of the global war against terrorism increases the need to undertake risk analysis of the options that until recently could have been dismissed as improbable. This article takes a deliberately pessimistic view on Russia, which continues to be a source of major security challenges, and attempts to measure the scale of possible disasters in medium-long perspective. This country, despite its present-day semblance of stability, may see a chain of violent conflicts engulfing the most vulnerable parts of its vast periphery—and some of those may pose such risks to international peace and security that external interventions might become necessary. The analysis examines the elements of the basic scenario of gradual erosion of the central authority in Russia under the impact of centrifugal forces and identifies a number of possible flash-points in the North, South, West and Far East of the country. The requirements for, and formats of external armed interventions in these low-intensity but high-risk conflicts are evaluated, while the fundamental issue of whether the West would be politically willing and militarily capable of performing any of the described interventions is deliberately left out.