Journal articles: 'Bead model'

1

Gaigalas, Adolfas K., Yu-Zhong Zhang, Linhua Tian, and Lili Wang. "Sources of Variability in the Response of Labeled Microspheres and B Cells during the Analysis by a Flow Cytometer." International Journal of Molecular Sciences 22, no. 15 (July 31, 2021): 8256. http://dx.doi.org/10.3390/ijms22158256.

Full text

Abstract:

A stochastic model of the flow cytometer measurement process was developed to assess the nature of the observed coefficient of variation (CV%) of the mean fluorescence intensity (MFI) from a population of labeled microspheres (beads). Several sources of variability were considered: the total number of labels on a bead, the path through the laser beam, the optical absorption cross-section, the quantum yield, the numerical aperture of the collection optics, and the photoelectron conversion efficiency of the photomultiplier (PMT) cathode. The variation in the number of labels on a bead had the largest effect on the CV% of the MFI of the bead population. The variation in the path of the bead through the laser beam was minimized using flat-top lasers. The variability in the average optical properties of the labels was of minor importance for beads with sufficiently large number of labels. The application of the bead results to the measured CV% of labeled B cells indicated that the measured CV% was a reliable measure of the variability of antibodies bound per cell. With some modifications, the model can be extended to multicolor flow cytometers and to the study of CV% from cells with low fluorescence signal.

APA, Harvard, Vancouver, ISO, and other styles

2

Sun, C. M., O. S. Sezgin, A. K. Forrest, and B. L. Davies. "Use of vision in dispensing control and inspection of adhesives." Robotica 9, no. 4 (December 1991): 371–77. http://dx.doi.org/10.1017/s0263574700000540.

Full text

Abstract:

SUMMARYA prototype system utilizing a vision technique to monitor the parameters of adhesive beads or sealants is presented. The system uses a structured light technique to investigate adhesive beads and extract information about the shape of the bead from binary images. The geometrical model of the bead, the relationship between this model and the shape of a line of light on the image are investigated. The models for calculating the parameters of the bead and the height of the camera are analyzed. Control strategies are suggested.

APA, Harvard, Vancouver, ISO, and other styles

3

Hernando, Iñigo, Jon Arrizubieta, Aitzol Lamikiz, and Eneko Ukar. "Numerical Model for Predicting Bead Geometry and Microstructure in Laser Beam Welding of Inconel 718 Sheets." Metals 8, no. 7 (July 12, 2018): 536. http://dx.doi.org/10.3390/met8070536.

Full text

Abstract:

A numerical model was developed for predicting the bead geometry and microstructure in laser beam welding of 2 mm thickness Inconel 718 sheets. The experiments were carried out with a 1 kW maximum power fiber laser coupled with a galvanometric scanner. Wobble strategy was employed for sweeping 1 mm wide circular areas for creating the weld seams, and a specific tooling was manufactured for supplying protective argon gas during the welding process. The numerical model takes into account both the laser beam absorption and the melt-pool fluid movement along the bead section, resulting in a weld geometry that depends on the process input parameters, such as feed rate and laser power. The microstructure of the beads was also estimated based on the cooling rate of the material. Features such as bead upper and bottom final shapes, weld penetration, and dendritic arm spacing, were numerically and experimentally analyzed and discussed. The results given by the numerical analysis agree with the tests, making the model a robust predictive tool.

APA, Harvard, Vancouver, ISO, and other styles

4

BLOM, J. G., and M. A. PELETIER. "A continuum model of lipid bilayers." European Journal of Applied Mathematics 15, no. 4 (August 2004): 487–508. http://dx.doi.org/10.1017/s0956792504005613.

Full text

Abstract:

We study a one-dimensional continuum model for lipid bilayers. The system consists of water and lipid molecules; lipid molecules are represented by two ‘beads’, a head bead and a tail bead, connected by a rigid rod. We derive a simplified model for such a system, in which we only take into account the effects of entropy and hydrophilic/hydrophobic interactions. We show that for this simple model membrane-like structures exist for certain choices of the parameters, and numerical calculations suggest that they are stable.

APA, Harvard, Vancouver, ISO, and other styles

5

Marciani, Luca, Penny A. Gowland, Annette Fillery-Travis, Pretima Manoj, Jeff Wright, Andrew Smith, Paul Young, Rachel Moore, and Robin C. Spiller. "Assessment of antral grinding of a model solid meal with echo-planar imaging." American Journal of Physiology-Gastrointestinal and Liver Physiology 280, no. 5 (May 1, 2001): G844—G849. http://dx.doi.org/10.1152/ajpgi.2001.280.5.g844.

Full text

Abstract:

Mathematical modeling of how physical factors alter gastric emptying is limited by lack of precise measures of the forces exerted on gastric contents. We have produced agar gel beads (diameter 1.27 cm) with a range of fracture strengths (0.15–0.90 N) and assessed their breakdown by measuring their half-residence time (RT1/2) using magnetic resonance imaging. Beads were ingested either with a high (HV)- or low (LV)-viscosity liquid nutrient meal. With the LV meal, RT1/2was similar for bead strengths ranging from 0.15 to 0.65 N but increased from 22 ± 2 min (bead strength <0.65 N) to 65 ± 12 min for bead strengths >0.65 N. With the HV meal, emptying of the harder beads was accelerated. The sense of fullness after ingesting the LV meal correlated linearly (correlation coefficient = 0.99) with gastric volume and was independently increased by the harder beads, which were associated with an increased antral diameter. We conclude that the maximum force exerted by the gastric antrum is close to 0.65 N and that gastric sieving is impaired by HV meals.

APA, Harvard, Vancouver, ISO, and other styles

6

Fixman, Marshall. "Polyelectrolyte bead model. I. Equilibrium." Journal of Chemical Physics 92, no. 10 (May 15, 1990): 6283–93. http://dx.doi.org/10.1063/1.458352.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Mijailovich, Srboljub M., Milos Kojic, Miroslav Zivkovic, Ben Fabry, and Jeffrey J. Fredberg. "A finite element model of cell deformation during magnetic bead twisting." Journal of Applied Physiology 93, no. 4 (October 1, 2002): 1429–36. http://dx.doi.org/10.1152/japplphysiol.00255.2002.

Full text

Abstract:

Magnetic twisting cytometry probes mechanical properties of an adherent cell by applying a torque to a magnetic bead that is tightly bound to the cell surface. Here we have used a three-dimensional finite element model of cell deformation to compute the relationships between the applied torque and resulting bead rotation and lateral bead translation. From the analysis, we computed two coefficients that allow the cell elastic modulus to be estimated from measurements of either bead rotation or lateral bead translation, respectively, if the degree of bead embedding and the cell height are known. Although computed strains in proximity of the bead can be large, the relationships between applied torque and bead rotation or translation remain virtually linear up to bead rotations of 15°, above which geometrical nonlinearities become significant. This appreciable linear range stands in contrast to the intrinsically nonlinear force-displacement relationship that is observed when cells are indented during atomic force microscopy. Finally, these computations support the idea that adhesive forces are sufficient to keep the bead firmly attached to the cell surface throughout the range of working torques.

APA, Harvard, Vancouver, ISO, and other styles

8

Yoga Saputra, I. Made, Nyoman Semadi Antara, and Ida Bagus Wayan Gunam. "PENGARUH KONSENTRASI Na-ALGINAT DAN UKURAN BEADS TERHADAP STABILITAS BEADS DAN AKTIVITAS SEL Agrobacterium tumefaciens LSU20 IMMOBIL DALAM BIODESULFURISASI DIBENZOTHIOFENA." JURNAL REKAYASA DAN MANAJEMEN AGROINDUSTRI 6, no. 2 (April 17, 2018): 169. http://dx.doi.org/10.24843/jrma.2018.v06.i02.p08.

Full text

Abstract:

The purpose of this study was to determine the concentration and size of Na-alginate beads that have the highest degradation activity of dibenzothiophene. Biodesulfurization (BDS) of dibenzothiophene (DBT) was performed using 3 Na-alginate concentrations and 3 different beads sizes in the oil model system. Biodesulfurization was performed with incubation for 24 hours. The previous research showed that sodium alginate (Na-alginate) was an appropriate immobilizing agent compared to other immobilized materials. Na-alginate 4% show the activity of the degradation of the most good that is 66.33% (bead size 2 mm), 62.99% (bead size 3 mm), 59.93% (bead size 4 mm), for concentration of 3% Na-alginate showed 65.58% (bead size 2 mm), 61.68% (bead size 3 mm) and 60.43% (bead size 4 mm), while concentration 5% showed the most low that is 64.86% (bead size 2 mm), 61.01% (bead size 3 mm), and 58.89% (bead size 4 mm). The stability test showed Na-alginate 4% have the stability and durability of the bead stronger, the test showed Na-alginate can be used up to five repeat and still have degradation activity. Key words: Biodesulfurization, Dibenzothiophene, Immobilized cells, Na-alginate.

APA, Harvard, Vancouver, ISO, and other styles

9

Siczek, Krzysztof, Wojciech Pawlak, Hubert Zatorski, and Jakub Fichna. "Measurement of Silver Nanolayer Absorption by the Body in an in Vivo Model of Inflammatory Gastrointestinal Diseases." Metrology and Measurement Systems 23, no. 1 (March 1, 2016): 133–42. http://dx.doi.org/10.1515/mms-2016-0008.

Full text

Abstract:

Abstract Layers of silver particles are used in the studies on pathophysiology and treatment of diseases, both in pre-clinical and clinical conditions. Silver layers can be formed using different techniques and on different substrates. Deposition by magnetron sputtering on glass beads was used in this study. Silver absorption by the body was estimated by calculating the difference in thickness of the silver nanolayer deposited on a bead and measured before and after application of the bead in an animal model of gastrointestinal inflammation. Recommendations for the minimal thickness of silver nanolayer deposited on glass beads were worked out for further studies.

APA, Harvard, Vancouver, ISO, and other styles

10

Boutillier, Cédric. "The bead model and limit behaviors of dimer models." Annals of Probability 37, no. 1 (January 2009): 107–42. http://dx.doi.org/10.1214/08-aop398.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Lunov, Oleg, Svetlana Bespalova, and Vitalii Zablotskii. "A model for magnetic bead microrheometry." Journal of Magnetism and Magnetic Materials 311, no. 1 (April 2007): 162–65. http://dx.doi.org/10.1016/j.jmmm.2006.10.1172.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Papon, Easir Arafat, Anwarul Haque, and Muhammad Ali Rob Sharif. "Numerical study for the improvement of bead spreading architecture with modified nozzle geometries in additive manufacturing of polymers." Rapid Prototyping Journal 27, no. 3 (February 4, 2021): 518–29. http://dx.doi.org/10.1108/rpj-05-2019-0142.

Full text

Abstract:

Purpose This paper aims to develop a numerical model of bead spreading architecture of a viscous polymer in fused filament fabrication (FFF) process with different nozzle geometry. This paper also focuses on the manufacturing feasibility of the nozzles and 3D printing of the molten beads using the developed nozzles. Design/methodology/approach The flow of a highly viscous polymer from a nozzle, the melt expansion in free space and the deposition of the melt on a moving platform are captured using the FLUENT volume of fluid (VOF) method based computational fluid dynamics code. The free surface motion of the material is captured in VOF, which is governed by the hydrodynamics of the two-phase flow. The phases involved in the numerical model are liquid polymer and air. A laminar, non-Newtonian and non-isothermal flow is assumed. Under such assumptions, the spreading characteristic of the polymer is simulated with different nozzle-exit geometries. The governing equations are solved on a regular stationary grid following a transient algorithm, where the boundary between the polymer and the air is tracked by piecewise linear interface construction (PLIC) to reconstruct the free surface. The prototype nozzles were also manufactured, and the deposition of the molten beads on a flatbed was performed using a commercial 3D printer. The deposited bead cross-sections were examined through optical microscopic examination, and the cross-sectional profiles were compared with those obtained in the numerical simulations. Findings The numerical model successfully predicted the spreading characteristics and the cross-sectional shape of the extruded bead. The cross-sectional shape of the bead varied from elliptical (with circular nozzle) to trapezoidal (with square and star nozzles) where the top and bottom surfaces are significantly flattened (which is desirable to reduce the void spaces in the cross-section). The numerical model yielded a good approximation of the bead cross-section, capturing most of the geometric features of the bead with a reasonable qualitative agreement compared to the experiment. The quantitative comparison of the cross-sectional profiles against experimental observation also indicated a favorable agreement. The significant improvement observed in the bead cross-section with the square and star nozzles is the flattening of the surfaces. Originality/value The developed numerical algorithm attempts to address the fundamental challenge of voids and bonding in the FFF process. It presents a new approach to increase the inter-bead bonding and reduce the inter-bead voids in 3D printing of polymers by modifying the bead cross-sectional shape through the modification of nozzle exit-geometry. The change in bead cross-sectional shape from elliptical (circular) to trapezoidal (square and star) cross-section is supposed to increase the contact surface area and inter-bead bonding while in contact with adjacent beads.

APA, Harvard, Vancouver, ISO, and other styles

13

Li, Peizhi, Yu Fan, Chonghao Zhang, Zhiyuan Zhu, Wenteng Tian, and Anmin Liu. "Research on Heat Source Model and Weld Profile for Fiber Laser Welding of A304 Stainless Steel Thin Sheet." Advances in Materials Science and Engineering 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/5895027.

Full text

Abstract:

A heat source model is the key issue for laser welding simulation. The Gaussian heat source model is not suitable to match the actual laser weld profile accurately. Furthermore, fiber lasers are widely recognized to result in good-quality laser beam output, a narrower weld zone, less distortion, and high process efficiency, compared with other types of lasers (such as CO2, Nd : YAG, and diode lasers). At present, there are few heat source models for fiber laser welding. Most of researchers evaluate the weld profile only by the bead width and depth of penetration, which is not suitable for the laser keyhole welding nail-like profile. This paper reports an experimental study and FEA simulation of fiber laser butt welding on 1 mm thick A304 stainless steel. A new heat source model (cylindrical and cylindrical) is established to match the actual weld profile using Marc and Fortran software. Four bead geometry parameters (penetration depth, bead width, waist width, and depth of the waist) are used to compare between the experimental and simulation results. The results show that the heat source model of cylindrical and cylindrical can match the actual shape of the fiber laser welding feasibly. The error range of the penetration depth, bead width, waist width, and depth of the waist between experimental and simulation results is about 4.1 ± 1.6%, 2.9 ± 2.0%, 13.6 ± 7.4/%, and 18.3 ± 8.0%, respectively. In addition, it is found that the depth of penetration is more sensitive to laser power rather than bead width, waist width, and depth of the waist. Welding speed has a similar influence on the depth of penetration, weld width, waist width, and depth of the waist.

APA, Harvard, Vancouver, ISO, and other styles

14

Li, Min, and John Z. H. Zhang. "Two-bead polarizable water models combined with a two-bead multipole force field (TMFF) for coarse-grained simulation of proteins." Physical Chemistry Chemical Physics 19, no. 10 (2017): 7410–19. http://dx.doi.org/10.1039/c6cp07958j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Balasubramanian, K. R., T. Suthakar, K. Sankaranarayanasamy, and G. Buvanashekaran. "Laser Welding Simulations of Stainless Steel Joints Using Finite Element Analysis." Advanced Materials Research 383-390 (November 2011): 6225–30. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.6225.

Full text

Abstract:

Laser beam welding (LBW) is a fusion joining process that uses the energy from a laser beam to melt and subsequently crystallize a metal, resulting in a bond between parts. In this study, finite element method (FEM) is used for predicting the weld bead profile of laser welding butt, lap and T-joints. A three-dimensional finite element model is used to analyze the temperature distribution weld bead shape for different weld configurations produced by the laser welding process. In the model temperature-dependent thermo physical properties of AISI304 stainless steel, effect of latent heat of fusion and convective and radiative boundary conditions are incorporated. The heat input to the FEM model is assumed to be a 3D conical Gaussian heat source. The finite element software SYSWELD is employed to obtain the numerical results. The computed weld bead profiles for butt, lap and T-joints are compared with the experimental profiles and are found to be in agreement.

APA, Harvard, Vancouver, ISO, and other styles

16

Zhou, Qin, and Paul L. Bishop. "Determination of oxygen profiles and diffusivity in encapsulated biomass k-carrageenan gel beads." Water Science and Technology 36, no. 1 (July 1, 1997): 271–77. http://dx.doi.org/10.2166/wst.1997.0064.

Full text

Abstract:

Biofiltration is a popular method for removing volatile organic compounds (VOCs). One promising medium for biofilters is biomass encapsulated gel beads. Like any other biodegradation system, oxygen concentration is an important factor affecting microbial activities in gel beads and thus the VOC removal efficiency. This paper summarizes the studies on oxygen distribution and diffusivity in k-carrageenan gel beads using oxygen microelectrodes to measure oxygen profiles. By using a reaction-diffusion model and the concentration measurements obtained, a homogeneous diffusivity constant and an oxygen consumption rate constant in k-carrageenan gel beads were estimated. The estimated oxygen diffusivity in the gel bead is 46.3% of the value in water when the bead is immersed in water and 53.9% that of water when the bead is in air with a thin liquid film surrounding it. To provide more information for the design and operation of biofilters using biomass-loaded gel beads, we also investigated and report on effects of biomass immobilization time, TCE influent concentration and TCE gas flow rate on oxygen concentrations in the gel bead.

APA, Harvard, Vancouver, ISO, and other styles

17

Shen, Cheng, Yaqian Zhao, Ranbin Liu, Yi Mao, and David Morgan. "Adsorption of phosphorus with calcium alginate beads containing drinking water treatment residual." Water Science and Technology 78, no. 9 (November 15, 2018): 1980–89. http://dx.doi.org/10.2166/wst.2018.473.

Full text

Abstract:

Abstract Aluminum-based drinking water treatment residuals (DWTR) were encapsulated by alginate to develop a pelletized media (DWTR-CA beads) for phosphorus (P) adsorption. The beads were successfully manufactured to uniform size and shape requirements. The effects of DWTR powder concentration and particle size, and bead mean size on P adsorption, were investigated. The DWTR was found to be an important component in the beads for P adsorption, while the calcium alginate shell contributed little for P adsorption. The maximum P adsorption capacity of the DWTR-CA bead was 19.42 mg P/g wet beads, corresponding to a bead diameter of 3.1 ± 0.2 mm and DWTR concentration of 2% (1% weight/volume (W/V)), mg/mL). The adsorption data fit well with the intra-particle diffusion model and the pseudo-second-order kinetic model, while both the Langmuir and Freundlich adsorption isotherms described the adsorption process well. Furthermore, the study on the effect of pH on P adsorption showed that acidic conditions resulted in a better P adsorption and the DWTR-CA beads have the function of pH neutralization. The findings of this study show that the DWTR-CA beads are a promising adsorbent/substrate for P removal.

APA, Harvard, Vancouver, ISO, and other styles

18

Suthakar, T., K. Sankaranarayanasamy, K. R. Balasubramanian, G. Buvanashekaran, and K. Krishna Murthy. "Effect of Peclet Number on the Thermo Capillary Convection and Molten Pool Shape Formation during Laser Welding Using CFD." Advanced Materials Research 383-390 (November 2011): 6231–35. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.6231.

Full text

Abstract:

A mathematical model is developed for the simulation of keyhole and molten pool formation during laser beam welding. Heat transfer from the key hole to the weld pool and details of the fluid flow play a major role in determining the weld bead profile. The simulation is performed based on the control volume method (CVM) and a volumetric heat source is used to model the laser beam and the equations of mass, momentum and energy are solved. The effect of Peclet number, Marangoni number, and Nusselt number is studied by varying process parameters like welding speed and beam power. The simulated bead profiles are compared with the experimental profile and are found to be acceptable.

APA, Harvard, Vancouver, ISO, and other styles

19

Maghsoodlou, Shima, and Sulmaz Poreskandar. "Controlling Electrospinning Jet Using Microscopic Model for Ideal Tissue Engineering Scaffolds." International Journal of Chemoinformatics and Chemical Engineering 5, no. 2 (July 2016): 1–16. http://dx.doi.org/10.4018/ijcce.2016070101.

Full text

Abstract:

Electrospinning has recently emerged as a widespread technology to produce synthetic nanofibrous and the best candidates for many important applications like scaffolds in tissue engineering. Creating porosity is the primary challenge of tissue engineering scaffolds. But, the most important challenge is to create uniform nanofibers. For these reasons, controlling producing of electrospun nanofiber becomes important. The most suitable method for controlling instability is using modeling and computer simulations. The dynamic analysis of the jet formation and its instability is difficult during the process. In this study, the behavior of the electrospinning process has been investigated by using bead-spring model to see the process in detail. Simulation of this model showed the jet behavior from the first second to the end by bringing in one bead step by step. Therefore, by increasing the number of beads, the behavior of jet during whipping part was obviously expressed.

APA, Harvard, Vancouver, ISO, and other styles

20

Coppersmith, S. N., C. h. Liu, S. Majumdar, O. Narayan, and T. A. Witten. "Model for force fluctuations in bead packs." Physical Review E 53, no. 5 (May 1, 1996): 4673–85. http://dx.doi.org/10.1103/physreve.53.4673.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Wu, Dan, and Joel Voldman. "An integrated model for bead-based immunoassays." Biosensors and Bioelectronics 154 (April 2020): 112070. http://dx.doi.org/10.1016/j.bios.2020.112070.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Amelar, S., C. E. Eastman, T. P. Lodge, and E. D. von Meerwall. "How good is the bead-spring model?" Journal of Non-Crystalline Solids 131-133 (June 1991): 551–55. http://dx.doi.org/10.1016/0022-3093(91)90647-o.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Kim, Jisun, Jaewoong Kim, Changmin Pyo, and Kwangsan Chun. "Bead Geometry Prediction Model for 9% Nickel Laser Weldment, Part 1: Global Regression Model vs. Modified Regression Model." Processes 9, no. 5 (April 30, 2021): 793. http://dx.doi.org/10.3390/pr9050793.

Full text

Abstract:

Due to its excellent toughness and stiffness in cryogenic conditions, 9% nickel steel is applied to LNG storage facilities, and its usage is increasing as a result of changes in environmental regulations. A study was conducted on the development of a predictive model to optimize the laser welding process of 9% nickel steel, and two prediction models were developed using one hundred data points obtained through experiments. A global regression model used as a general prediction model and a modified regression model using the p-value of the analysis of variance were developed, and their prediction performance was compared. It was found that the modified regression model was superior to the global regression model in terms of predicting the bead shape, including parameters such as penetration depth, bead height, and area ratio.

APA, Harvard, Vancouver, ISO, and other styles

24

Dashtdar, Havva, Malliga Raman Murali, Lakshmi Selvaratnam, Hanumantharao Balaji Raghavendran, Abdulrazzaq Mahmod Suhaeb, Tunku Sara Ahmad, and Tunku Kamarul. "Ultra-structural changes and expression of chondrogenic and hypertrophic genes during chondrogenic differentiation of mesenchymal stromal cells in alginate beads." PeerJ 4 (March 1, 2016): e1650. http://dx.doi.org/10.7717/peerj.1650.

Full text

Abstract:

Chondrogenic differentiation of mesenchymal stromal cells (MSCs) in the form of pellet culture and encapsulation in alginate beads has been widely used as conventional model forin vitrochondrogenesis. However, comparative characterization between differentiation, hypertrophic markers, cell adhesion molecule and ultrastructural changes during alginate and pellet culture has not been described. Hence, the present study was conducted comparing MSCs cultured in pellet and alginate beads with monolayer culture. qPCR was performed to assess the expression of chondrogenic, hypertrophic, and cell adhesion molecule genes, whereas transmission electron microscopy (TEM) was used to assess the ultrastructural changes. In addition, immunocytochemistry for Collagen type II and aggrecan and glycosaminoglycan (GAG) analysis were performed. Our results indicate that pellet and alginate bead cultures were necessary for chondrogenic differentiation of MSC. It also indicates that cultures using alginate bead demonstrated significantly higher (p < 0.05) chondrogenic but lower hypertrophic (p < 0.05) gene expressions as compared with pellet cultures. N-cadherin and N-CAM1 expression were up-regulated in second and third weeks of culture and were comparable between the alginate bead and pellet culture groups, respectively. TEM images demonstrated ultrastructural changes resembling cell death in pellet cultures. Our results indicate that using alginate beads, MSCs express higher chondrogenic but lower hypertrophic gene expression. Enhanced production of extracellular matrix and cell adhesion molecules was also observed in this group. These findings suggest that alginate bead culture may serve as a superior chondrogenic model, whereas pellet culture is more appropriate as a hypertrophic model of chondrogenesis.

APA, Harvard, Vancouver, ISO, and other styles

25

Yamamoto, Yasuhiro, Rikio Soda, Junya Kano, and Fumio Saito. "DEM simulation of bead motion during wet bead milling using an enlarged particle model." International Journal of Mineral Processing 114-117 (November 2012): 93–99. http://dx.doi.org/10.1016/j.minpro.2012.10.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Pham, Tri Thanh, P. Sunthar, and J. Ravi Prakash. "An alternative to the bead-rod model: Bead-spring chains with successive fine graining." Journal of Non-Newtonian Fluid Mechanics 149, no. 1-3 (February 2008): 9–19. http://dx.doi.org/10.1016/j.jnnfm.2007.05.012.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Thao, D. T., and Il Soo Kim. "An Evaluation Approach for Prediction of Process Parameters with Genetic Algorithm." Materials Science Forum 580-582 (June 2008): 375–78. http://dx.doi.org/10.4028/www.scientific.net/msf.580-582.375.

Full text

Abstract:

Gas Metal Arc (GMA) welding process has widely been employed due to the wide range of applications, cheap consumables and easy handling. A suitable mathematical model to achieve a high level of welding performance and quality should be required to study the characteristics for the effects of process parameters on the bead geometry in the GMA welding process. The objective of this paper is to present development of three empirical models (linear, curvilinear and intelligent model) based on full factorial design with two replications to estimate process parameters on top-bead width in robotic GMA welding process. Regression analysis was employed for optimization of the coefficients of linear and curvilinear models, but Genetic Algorithm (GA) was utilized to estimate the coefficients of intelligent model. ANOVA analysis using experimental data were carried out representation of main and interaction effects between process parameters on top-bead width. Resulting solutions and graphical representation showed that the developed intelligent model can be used for prediction on top-bead width in robotic GMA welding process

APA, Harvard, Vancouver, ISO, and other styles

28

Kurfess, T. R., D. E. Whitney, and M. L. Brown. "Verification of a Dynamic Grinding Model." Journal of Dynamic Systems, Measurement, and Control 110, no. 4 (December 1, 1988): 403–9. http://dx.doi.org/10.1115/1.3152703.

Full text

Abstract:

Many applications of industrial robot automation can be made possible or improved with the introduction of a force feedback system. The task of weld bead removal is being studied in an effort to develop a real time force controlled intelligent system. The process of weld bead grinding must be analyzed and modelled to develop a weld bead removal system. Previous research has developed and verified static models of grinding. This paper describes a dynamic model developed from the grinding characteristics demonstrated previously. An experimental grinding system was built and the measured process behavior was compared with a grinding simulation based on the dynamic model. The profile of the specimen was measured prior to and subsequent to grinding. The initial profile was used as an input to the simulation, and the output from the simulation was compared with the final measured profile. A variety of conditions was tested. For typical mean cut depths of 0.10 mm the simulator predicted the final height of the grinding specimen within a standard deviation of 0.02 mm. The dynamic model was verified within 10 percent of the actual results.

APA, Harvard, Vancouver, ISO, and other styles

29

Lee, Ki-Yong, and Tae-Ryeon Heo. "Survival of Bifidobacterium longumImmobilized in Calcium Alginate Beads in Simulated Gastric Juices and Bile Salt Solution." Applied and Environmental Microbiology 66, no. 2 (February 1, 2000): 869–73. http://dx.doi.org/10.1128/aem.66.2.869-873.2000.

Full text

Abstract:

ABSTRACT Bifidobacterium longum KCTC 3128 and HLC 3742 were independently immobilized (entrapped) in calcium alginate beads containing 2, 3, and 4% sodium alginate. When the bifidobacteria entrapped in calcium alginate beads were exposed to simulated gastric juices and a bile salt solution, the death rate of the cells in the beads decreased proportionally with an increase in both the alginate gel concentration and bead size. The initial cell numbers in the beads affected the numbers of survivors after exposure to these solutions; however, the death rates of the viable cells were not affected. Accordingly, a mathematical model was formulated which expressed the influences of several parameters (gel concentration, bead size, and initial cell numbers) on the survival of entrapped bifidobacteria after sequential exposure to simulated gastric juices followed by a bile salt solution. The model proposed in this paper may be useful for estimating the survival of bifidobacteria in beads and establishing optimal entrapment conditions.

APA, Harvard, Vancouver, ISO, and other styles

30

Lumsden, Simone, John P. Singh, Ronnie G. Morgan, and Gregory Hundt. "Rheological Characterization of Suspension of Hollow Glass Beads." SPE Journal 22, no. 05 (June 8, 2017): 1671–80. http://dx.doi.org/10.2118/181347-pa.

Full text

Abstract:

Summary Hollow glass spheres (beads) are widely used as density and rheological modifiers for various oil and gas process fluids, particularly cement. One of the primary uses is to achieve lightweight slurries with good mechanical properties of the set cement. This paper discusses a concentrated, yet pumpable, suspension of these spheres for offshore cementing applications. Providing the lightweight spheres in a liquid suspension eliminates the risks associated with dry blending these materials. The development of the liquid suspension of hollow beads enables on-the-fly mixing of cement slurries with desired density profiles. Currently, the beads are premixed in the cement powder before they are shipped to offshore locations, which could result in the segregation of the beads during delivery and storage, and limits operations to the predetermined density (concentration of beads) of the slurry. This paper presents the rheological behavior of the concentrated suspension (up to 60% vol/vol) of hollow glass spheres suspended in a dilute aqueous solution of bentonite and soda ash. In addition, an attachment to the viscometer (called Fann Yield Stress Adaptor or FYSA) was used to characterize the flow behavior. A rheological model was developed to highlight the bead/bead surface interactions as a major component controlling flow behavior. Four different variants of beads were studied. These were selected to represent a range in surface area per unit volume of beads. Increasing the concentration of beads or the bentonite in solution correlated to increased yield stress and fluid viscosity at operational shear rates. In addition, a Krieger-Dougherty-type relation captured well the effect of the bead concentration, with the maximum packing fraction of beads as a function of surface area per unit volume of the beads. Overall, the Herschel-Bulkley (HB) model best described the suspension rheology with the shear-thinning exponent in the range of ≈0.8 to 1.0. Surface area of the beads linearly correlated to the yield stress of the corresponding concentrated bead solution. Results of this study and the model developed can be used to develop variants of the system with minimal experimentation, thus significantly shortening the design time.

APA, Harvard, Vancouver, ISO, and other styles

31

Craig, J. M., A. L. Scott, and W. Mitzner. "Elastase-coupled beads as a tool for characterizing localized alveolar tissue destruction associated with the onset of emphysema." Journal of Applied Physiology 114, no. 11 (June 1, 2013): 1637–44. http://dx.doi.org/10.1152/japplphysiol.00026.2013.

Full text

Abstract:

Intratracheal elastase challenge of laboratory animals has long been established as a model for observing the physiological and morphological changes that result from alveolar destruction, the hallmark of emphysema. However, instillation of elastase suspended in buffer results in widespread inflammation and variable emphysematous lesions, which has made the identification of specific cellular and molecular events associated with the onset of emphysema difficult to define. Here we establish a bead-based elastase delivery system that induces localized tissue destruction, a key event in the initiation of emphysema. Elastase was coupled to bisacrylamide beads, which were shown to retain enzymatic activity prior to intratracheal administration in mice. C57BL/6 mice were given a single dose of 40,000 beads, which became distributed throughout the small airways and parenchyma of the lung. Elastase-coupled beads resulted in a quantifiable loss of alveolar tissue immediately surrounding the beads, an effect that was not observed with beads that lacked protein altogether or with beads containing elastase inactivated by an irreversible inhibitor. Furthermore, beads bound with active elastase elicited local recruitment of mononuclear cells, including macrophages, and polymorphonuclear neutrophils to the site of bead deposition, a feature consistent with the cellular infiltration observed following conventional solubilized elastase challenges. This work identifies a novel bead-based enzyme delivery system that also extends the elastase model of emphysema to permit the characterization of mechanisms that drive alveolar surface area loss following elastin degradation in focal emphysematous lesions.

APA, Harvard, Vancouver, ISO, and other styles

32

Bize, Pierre E., Olivier Jordan, Katrin Fuchs, Olivier Dormond, Rafael Duran, Eric Doelker, Thierry De Baere, and Alban Denys. "Evaluation of the antitumoral effect sunitinib eluting beads in VX2 liver tumour in a rabbit model." Journal of Clinical Oncology 31, no. 4_suppl (February 1, 2013): 247. http://dx.doi.org/10.1200/jco.2013.31.4_suppl.247.

Full text

Abstract:

247 Background: We demonstrated that DC Bead (Biocompatibles UK, Ltd) could be loaded with sunitinib and injected intra-arterially in the rabbit without unexpected toxicity. The purpose of this study is to evaluate the antitumoral effect of sunitinib eluting beads in the VX2 tumor model of liver cancer. Methods: VX2 tumors were implanted in the left liver lobe of New-Zealand white rabbits. Animals were assigned to 3 groups: Group 1 (n=6) received 1.5mg of sunitinib loaded in 0.05ml of 100-300um DC Bead, group 2 (n=5) received 0.05ml of 100-300um DC Bead, group 3 (n=5) received 0.05ml NaCl 0.9% in the left hepatic artery. One animal in each group was sacrificed at 24 hours and the others were followed for survival until day 15. Liver enzymes were measured daily. In group 1, plasmatic sunitinib concentration were measured daily by LC MS/MS tandem mass spectroscopy. At day 15 all living animals were sacrificed. After sacrifice, the livers were harvested for determination of the VEGF receptor tyrosine kinase activity by western blot and histopathological examination. Results: In group 1, no animals died during follow-up. In group 2, 2 animals died during follow-up on day x. In control group 3, 3 animals died during follow up on day x. In group 1 plasmatic sunitinib levels remained under therapeutic concentration throughout the experiment. Very high concentrations of sunitinib were measured in the liver tissue 24 and 15 days after embolization. Inhibition of the phosphorylation of the RTK was demonstrated at 24h and 15 days in groups 1. Sunitinib eluting beads seemed to penetrate in the tumor more effectively and there was more necrosis around the beads than their bland counterparts. Conclusions: Administration of sunitinib eluting beads in VX2 carrying rabbits resulted invery high drug concentrations at the site of embolization with minimal systemic passage. Despite the very high tissular sunitinib concentration we did not observe any additional toxicity with loaded beads. Sunitinib eluting beads inhibit the activation of RTK’s triggered by ischemia and seem to prolong survival of the treated animals. Therefore we consider that local treatment with sunitinib may provide a promising approach for the treatment of liver cancer.

APA, Harvard, Vancouver, ISO, and other styles

33

Aggarwal, Kush, R. J. Urbanic, and Syed Mohammad Saqib. "Development of predictive models for effective process parameter selection for single and overlapping laser clad bead geometry." Rapid Prototyping Journal 24, no. 1 (January 2, 2018): 214–28. http://dx.doi.org/10.1108/rpj-04-2016-0059.

Full text

Abstract:

Purpose The purpose of this work is to explore predictive model approaches for selecting laser cladding process settings for a desired bead geometry/overlap strategy. Complementing the modelling challenges is the development of a framework and methodologies to minimize data collection while maximizing the goodness of fit for the predictive models. This is essential for developing a foundation for metallic additive manufacturing process planning solutions. Design/methodology/approach Using the coaxial powder flow laser cladding method, 420 steel cladding powder is deposited on low carbon structural steel plates. A design of experiments (DOE) approach is taken using the response surface methodology (RSM) to establish the experimental configuration. The five process parameters such as laser power, travel speed, etc. are varied to explore their impact on the bead geometry. A total of three replicate experiments are performed and the collected data are assessed using a variety of methods to determine the process trends and the best modelling approaches. Findings There exist unpredictable, non-linear relationships between the process parameters and the bead geometry. The best fit for a predictive model is achieved with the artificial neural network (ANN) approach. Using the RSM, the experimental set is reduced by an order of magnitude; however, a model with R2 = 0.96 is generated with ANN. The predictive model goodness of fit for a single bead is similar to that for the overlapping bead geometry using ANN. Originality/value Developing a bead shape to process parameters model is challenging due to the non-linear coupling between the process parameters and the bead geometry and the number of parameters to be considered. The experimental design and modelling approaches presented in this work illustrate how designed experiments can minimize the data collection and produce a robust predictive model. The output of this work will provide a solid foundation for process planning operations.

APA, Harvard, Vancouver, ISO, and other styles

34

Hallé, Jean-Pierre, François A. Leblond, Jean-François Pariseau, Paul Jutras, Marie-Josée Brabant, and Yves Lepage. "Studies on Small (<300 μm) Microcapsules: II — Parameters Governing the Production of Alginate Beads by High Voltage Electrostatic Pulses." Cell Transplantation 3, no. 5 (September 1994): 365–72. http://dx.doi.org/10.1177/096368979400300503.

Full text

Abstract:

The size of microcapsules is a critical parameter in the immunoisolation of islets of Langerhans by microencapsulation. The use of smaller capsules decreases the total implant volume and improves insulin kinetics and oxygen supply. A high voltage electrostatic pulse system was used for the production of small (<300 μm) alginate beads, the first step of the encapsulation technique. However, islets often protruded from capsules that were too small, further emphasizing the need for a method to control bead size. A study of 7 parameters [electrostatic pulse amplitude (A), duration (D) and wavelength (λ), pump flow rate (P), needle gauge, alginate viscosity and distance between electrodes] showed that P (r = 0.981, p = 0.003) and λ (r = 0.988, p = 0.0002) were the principal determinants of bead size. To detect potential interactions between parameters, 270 combinations of different levels of A, D, λ, and P were studied. A multivariate regression analysis of these data confirmed that P and λ are the prime determinants of bead size, and showed that a 2-parameter (P, λ) model could be used to precisely predict bead size (R2 = 0.84), while keeping the application simple. The precision of the predictive model is only slightly improved by the use of additional parameters. The reliability of the data used to elaborate this model was demonstrated (p = 0.6226) by comparing them with a second data set obtained under the same conditions. A third set of experiments confirmed the applicability of the model. This work has major implications on the preclinical application of microencapsulation since it showed that it is possible to predetermine the bead size.

APA, Harvard, Vancouver, ISO, and other styles

35

Abu-Hassan, Diala Walid, Mahmoud Yousef Alkawareek, Rania “Ahmad Azzam” Hamed, Fahmy Banat, and Saja Al-Muhtaseb. "Host‐parasite Interaction Model Using Bead‐Grown Biofilms." FASEB Journal 34, S1 (April 2020): 1. http://dx.doi.org/10.1096/fasebj.2020.34.s1.09305.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Barkema, Gerard T., Debabrata Panja, and J. M. J. van Leeuwen. "Semiflexible polymer dynamics with a bead-spring model." Journal of Statistical Mechanics: Theory and Experiment 2014, no. 11 (November 6, 2014): P11008. http://dx.doi.org/10.1088/1742-5468/2014/11/p11008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Villada-Balbuena, Mario, and Mauricio D. Carbajal-Tinoco. "One-bead coarse-grained model for RNA dynamics." Journal of Chemical Physics 146, no. 4 (January 28, 2017): 045101. http://dx.doi.org/10.1063/1.4974899.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Liu, Bin, Jizeng Wang, Xiaojun Fan, Yong Kong, and Huajian Gao. "An effective bead–spring model for polymer simulation." Journal of Computational Physics 227, no. 5 (February 2008): 2794–807. http://dx.doi.org/10.1016/j.jcp.2007.11.012.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Sangjan, Suntree, and Wadchara Thongsamer. "Application of Photocatalytic and Adsorption Process for Residue Organic Degradation Using Doped ZnO Composites Hydrogel Beads." Key Engineering Materials 858 (August 2020): 109–15. http://dx.doi.org/10.4028/www.scientific.net/kem.858.109.

Full text

Abstract:

This research aimes to synthesize photocatalyst-sodium alginate composite hydrogel beads which apply for coupled adsorption and photocatalytic degradation of organic residue. Fe3O4, graphitic carbon nitride (g-C3N4), grapheme oxide (GO) and AgNO3 doped ZnO photocatalyst composites hydrogel beads were synthesized and characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). Photocatalytic and adsorption activity are studied by Methylene blue (MB) degradation under sunshine irradiation. The effect of different parameter as photocatalyst types and reaction time were studied upon the efficiency of organic residue degradation. The coupled photocatalytic and adsorption processes were evaluated through various kinetic models such as pseudo-first-order/ pseudo-second-order in Langmuir-Hinshelwood model model, the Elovich model and the intra particle diffusion model. Kinetics studies showed that the coupled photocatalytic and adsorption processes in photodegradation of all sample was well described by the pseudo-second-order model because R2 of all sample were close to 1 which compared with another model. For photodegradation efficiency, the best choice in this condition was g-C3N4 doped ZnO composite hydrogel bead. Photodegradation efficiency and the pseudo second order rate constant of photocatalyst ZnO+gC3N4/SA composite hydrogel bead were 83.80%(for 180 min and up to 96% for 7 hr) and 5.05×10-3 g.mg-1 min-1, respectively.

APA, Harvard, Vancouver, ISO, and other styles

40

Akino, Yuichi, Shintaro Maruoka, Katsuyuki Yano, Hiroshi Abe, Fumiaki Isohashi, Yuji Seo, Keisuke Tamari, et al. "Commissioning of total body irradiation using plastic bead bags." Journal of Radiation Research 61, no. 6 (September 2, 2020): 959–68. http://dx.doi.org/10.1093/jrr/rraa072.

Full text

Abstract:

Abstract The goal of total body irradiation (TBI) is to deliver a dose to the whole body with uniformity within ±10%. The purpose of this study was to establish the technique of TBI using plastic bead bags. A lifting TBI bed, Model ORP-TBI-MN, was used. The space between the patient’s body and the acrylic walls of the bed was filled with polyacetal bead bags. Patients were irradiated by a 10 MV photon beam with a source to mid-plane distance of 400 cm. The monitor unit (MU) was calculated by dose-per-MU, tissue-phantom-ratio and a spoiler factor measured in solid water using an ionization chamber. The phantom-scatter correction factor, off-center ratio and the effective density of the beads were also measured. Diode detectors were used for in vivo dosimetry (IVD). The effective density of the beads was 0.90 ± 0.09. The point doses calculated in an I’mRT phantom with and without heterogeneity material showed good agreement, with measurements within 3%. An end-to-end test was performed using a RANDO phantom. The mean ± SD (range) of the differences between the calculated and IVD-measured mid-plane doses was 1.1 ± 4.8% (−5.9 to 5.0%). The differences between the IVD-measured doses and the doses calculated with Acuros XB of the Eclipse treatment planning system (TPS) were within 5%. For two patients treated with this method, the differences between the calculated and IVD-measured doses were within ±6% when excluding the chest region. We have established the technique of TBI using plastic bead bags. The TPS may be useful to roughly estimate patient dose.

APA, Harvard, Vancouver, ISO, and other styles

41

Li, Ran, Manshu Dong, and Hongming Gao. "Prediction of Bead Geometry with Changing Welding Speed Using Artificial Neural Network." Materials 14, no. 6 (March 18, 2021): 1494. http://dx.doi.org/10.3390/ma14061494.

Full text

Abstract:

Bead size and shape are important considerations for industry design and quality detection. It is hard to deduce an appropriate mathematical model for predicting the bead geometry in a continually changing welding process due to the complex interrelationship between different welding parameters and the actual bead. In this paper, an artificial neural network model for predicting the bead geometry with changing welding speed was developed. The experiment was performed by a welding robot in gas metal arc welding process. The welding speed was stochastically changed during the welding process. By transient response tests, it was indicated that the changing welding speed had a spatial influence on bead geometry, which ranged from 10 mm backward to 22 mm forward with certain welding parameters. For this study, the input parameters of model were the spatial welding speed sequence, and the output parameters were bead width and reinforcement. The bead geometry was recognized by polynomial fitting of the profile coordinates, as measured by a structured laser light sensor. The results showed that the model with the structure of 33-6-2 had achieved high accuracy in both the training dataset and test dataset, which were 99% and 96%, respectively.

APA, Harvard, Vancouver, ISO, and other styles

42

Balasubramanian, K. R., T. Suthakar, K. Sankaranarayanasamy, and G. Buvanashekaran. "Numerical Studies on Heat Transfer and Fluid Flow during Laser Welding of Thin Sheet." Applied Mechanics and Materials 592-594 (July 2014): 571–78. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.571.

Full text

Abstract:

Numerical simulation of heat transfer and fluid flow analysis of laser welding is essential to understand the physics of fluid motion, thermal cycles, heating and cooling rate and its effect on the formation of the final weld bead profile. The fusion geometry, weld thermal cycles, temperature and velocity field will vary depending on the welding process parameters. The influence of process parameters on the formation of weld bead geometry was analyzed in this study. In the simulation a plane Gaussian profile heat source was used to model the laser beam considering the equations of mass, momentum and energy. It was observed that due to the difference in surface tension coefficient the fluid moves from the central region of the molten pool to the outside. Increase in beam power or decrease in welding speed resulted in a high heating rate and less cooling rate due to high heat input. The simulated bead profiles were compared with the experimentally measured profile and was found to be in agreement.

APA, Harvard, Vancouver, ISO, and other styles

43

Xiao, C., and D. M. Heyes. "Effects of bead-bead interactions on the static and dynamical properties of model polymer solutions." Physical Review E 60, no. 5 (November 1, 1999): 5757–67. http://dx.doi.org/10.1103/physreve.60.5757.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Prajadhiama, Keval P., Yupiter HP Manurung, Zaidi Minggu, Fetisia HS Pengadau, Marcel Graf, Andre Haelsig, Tom-Eric Adams, and Hui Leng Choo. "Development of Bead Modelling for Distortion Analysis Induced by Wire Arc Additive Manufacturing using FEM and Experiment." MATEC Web of Conferences 269 (2019): 05003. http://dx.doi.org/10.1051/matecconf/201926905003.

Full text

Abstract:

In this research, Wire Arc Additive Manufacturing is modelled and simulated to determine the most suitable bead modelling strategy. This analysis is aimed to predict distortion by means of thermomechanical Finite Element Method (FEM). The product model with wire as feedstock on plate as substrate and process simulation are designed in form of multi-layered beads and single string using MSC Marc/Mentat. This research begins with finding suitable WAAM parameters which takes into account the bead quality. This is done by using robotic welding system with 01.2mm filler wire (AWS A5.28 : ER80SNi1), shielding gas (80% Ar/ 20% CO2) and 6mm-thick low carbon steel as base plate. Further, modelling as well as simulation are to be conducted with regards to bead spreading of each layers. Two different geometrical modelling regarding the weld bead are modelled which are arc and rectangular shape. Equivalent material properties from database and previous researches are implemented into simulation to ensure a realistic resemblance. It is shown that bead modelling with rectangular shape exhibits faster computational time with less error percentage on distortion result compared to arc shape. Moreover, by using the rectangular shape, the element and meshing are much easier to be designed rather than arc shape bead.

APA, Harvard, Vancouver, ISO, and other styles

45

Santhana Babu, A. V., P. K. Giridharan, P. Ramesh Narayanan, and S. V. S. Narayana Murty. "Prediction of Bead Geometry for Flux Bounded TIG Welding of AA 2219-T87 Aluminum Alloy." Journal of Advanced Manufacturing Systems 15, no. 02 (April 27, 2016): 69–84. http://dx.doi.org/10.1142/s0219686716500074.

Full text

Abstract:

To improve penetration capability of Tungsten Inert Gas (TIG) process, Flux Bounded TIG (FBTIG) is investigated in aluminum alloy AA 2219 T87. Characterization of this process is essential to predict and control the weld bead quality. For characterization, design of experiments based on central composite rotatable design is employed for the experiments. Response Surface Methodology (RSM) is used to develop a mathematical model to correlate the bead geometry with controllable process variables. The model developed is checked for its adequacy by regression by using the [Formula: see text]-test and Analysis of Variance (ANOVA). By backward elimination method, reduced model is obtained from the full model. The process parameters are optimized to get desired weld bead geometry. The model is validated by confirmatory tests. The main and interaction effects of the process variables on bead geometry are presented in graphical form. The results are useful to predict the weld bead geometry for different combinations of process variables.

APA, Harvard, Vancouver, ISO, and other styles

46

Han, Yo-Sub, Hwee Kim, Trent A. Rogers, and Shinnosuke Seki. "Self-Attraction Removal from Oritatami Systems." International Journal of Foundations of Computer Science 30, no. 06n07 (September 2019): 1047–67. http://dx.doi.org/10.1142/s0129054119400288.

Full text

Abstract:

RNA cotranscriptional folding refers to the phenomenon in which an RNA transcript folds upon itself while being synthesized out of a gene by an RNA polymerase. Oritatami is a computational model of this phenomenon, which lets its sequence of beads (abstract molecules) taken from a finite alphabet [Formula: see text] fold cotranscriptionally via interactions between beads according to its rule set. In this paper, we study the problem of removing self-attractions, which lets a bead interact with another bead of the same kind, from a given oritatami system without changing its behavior. Self-attraction is one of the major challenges in the construction of intrinsic oritatami systems, which can simulate even the dynamics of all the oritatami systems.

APA, Harvard, Vancouver, ISO, and other styles

47

Richard, Mathieu, Carles Blanch-Mercader, Hajer Ennomani, Wenxiang Cao, Enrique M. De La Cruz, Jean-François Joanny, Frank Jülicher, Laurent Blanchoin, and Pascal Martin. "Active cargo positioning in antiparallel transport networks." Proceedings of the National Academy of Sciences 116, no. 30 (July 9, 2019): 14835–42. http://dx.doi.org/10.1073/pnas.1900416116.

Full text

Abstract:

Cytoskeletal filaments assemble into dense parallel, antiparallel, or disordered networks, providing a complex environment for active cargo transport and positioning by molecular motors. The interplay between the network architecture and intrinsic motor properties clearly affects transport properties but remains poorly understood. Here, by using surface micropatterns of actin polymerization, we investigate stochastic transport properties of colloidal beads in antiparallel networks of overlapping actin filaments. We found that 200-nm beads coated with myosin Va motors displayed directed movements toward positions where the net polarity of the actin network vanished, accumulating there. The bead distribution was dictated by the spatial profiles of local bead velocity and diffusion coefficient, indicating that a diffusion-drift process was at work. Remarkably, beads coated with heavy–mero-myosin II motors showed a similar behavior. However, although velocity gradients were steeper with myosin II, the much larger bead diffusion observed with this motor resulted in less precise positioning. Our observations are well described by a 3-state model, in which active beads locally sense the net polarity of the network by frequently detaching from and reattaching to the filaments. A stochastic sequence of processive runs and diffusive searches results in a biased random walk. The precision of bead positioning is set by the gradient of net actin polarity in the network and by the run length of the cargo in an attached state. Our results unveiled physical rules for cargo transport and positioning in networks of mixed polarity.

APA, Harvard, Vancouver, ISO, and other styles

48

Guner, Gulenay, Dogacan Yilmaz, and Ecevit Bilgili. "Kinetic and Microhydrodynamic Modeling of Fenofibrate Nanosuspension Production in a Wet Stirred Media Mill." Pharmaceutics 13, no. 7 (July 10, 2021): 1055. http://dx.doi.org/10.3390/pharmaceutics13071055.

Full text

Abstract:

This study examined the impact of stirrer speed and bead material loading on fenofibrate particle breakage during wet stirred media milling (WSMM) via three kinetic models and a microhydrodynamic model. Evolution of median particle size was tracked via laser diffraction during WSMM operating at 3000–4000 rpm with 35–50% (v/v) concentration of polystyrene or zirconia beads. Additional experiments were performed at the center points of the above conditions, as well as outside the range of these conditions, in order to test the predictive capability of the models. First-order, nth-order, and warped-time kinetic models were fitted to the data. Main effects plots helped to visualize the influence of the milling variables on the breakage kinetics and microhydrodynamic parameters. A subset selection algorithm was used along with a multiple linear regression model (MLRM) to delineate how the breakage rate constant k was affected by the microhydrodynamic parameters. As a comparison, a purely empirical correlation for k was also developed in terms of the process/bead parameters. The nth-order model was found to be the best model to describe the temporal evolution; nearly second-order kinetics (n ≅ 2) was observed. When the process was operated at a higher stirrer speed and/or higher loading with zirconia beads as opposed to polystyrene beads, the breakage occurred faster. A statistically significant (p-value ≤ 0.01) MLRM of three microhydrodynamic parameters explained the variation in the breakage rate constant best (R2 ≥ 0.99). Not only do the models and the nth-order kinetic–microhydrodynamic correlation enable deeper process understanding toward developing a WSMM process with reduced cycle time, but they also provide good predictive capability, while outperforming the purely empirical correlation.

APA, Harvard, Vancouver, ISO, and other styles

49

Ravikumar, S. M., and P. Vijian. "Development of Mathematical Models for Prediction of Weld Bead Geometry of GTAW Stainless Steel." Applied Mechanics and Materials 867 (July 2017): 88–96. http://dx.doi.org/10.4028/www.scientific.net/amm.867.88.

Full text

Abstract:

Welding input process parameters are playing a very significant role in determining the weld bead quality. The quality of the joint can be defined in terms of properties such as weld bead geometry, mechanical properties and distortion. Experiments were conducted to develop models, using a three factor, five level factorial design for 304 stainless steel as base plate with ER 308L filler wire of 1.6 mm diameter. The purpose of this study is to develop the mathematical model and compare the observed output values with predicted output values. Welding current, welding speed and nozzle to plate distance were chosen as input parameters, while depth of penetration, weld bead width, reinforcement and dilution as output parameters. The models developed have been checked for their adequacy. Confirmation experiments were also conducted and the results show that the models developed can predict the bead geometries and dilution with reasonable accuracy. The direct and interaction effect of the process parameters on bead geometry are presented in graphical form.

APA, Harvard, Vancouver, ISO, and other styles

50

Noor, C. W. Mohd, Manuhutu Ferry, and W. B. Wan Nik. "A Study of Software Approach for Predicting Weld Bead Geometry in Shielded Metal Arc Welding (SMAW) Process." Applied Mechanics and Materials 554 (June 2014): 386–90. http://dx.doi.org/10.4028/www.scientific.net/amm.554.386.

Full text

Abstract:

The prediction of the optimal weld bead width is an important aspect in shielded metal arc welding (SMAW) process as it is related to the strength of the weld. This paper focuses on investigation of the development of the simple and accurate model for prediction of weld bead geometry. The experiment used welding current, arc length, welding speed, welding gap and electrode diameter as input parameters. While output parameters are bead width, depth of penetration and weld reinforcement. A number of 33 mild steel plate specimens had undergone the SMAW welding process. The experimental data was used to develop mathematical models using SPSS software. The actual and predicted values of the weld bead geometry are compared. The proposed models shows positive correlation to the real process.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Bead model'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles