scholarly journals On the Adequacy of Some Low-Order Moments Method to Simulate Certain Particle Removal Processes

2021 ◽  
Vol 5 (4) ◽  
pp. 46
Author(s):  
Margaritis Kostoglou ◽  
Thodoris D. Karapantsios
Keyword(s):  
Method Of Moments ◽  
Degrees Of Freedom ◽  
Normal Approximation ◽  
Particle Removal ◽  
The Past ◽  
Moments Method ◽  
Removal Processes ◽  
Indispensable Tool ◽  
Log Normal ◽  
Colloid Systems

The population balance is an indispensable tool for studying colloidal, aerosol, and, in general, particulate systems. The need to incorporate spatial variation (imposed by flow) to it invokes the reduction of its complexity and degrees of freedom. It has been shown in the past that the method of moments and, in particular, the log-normal approximation can serve this purpose for certain phenomena and mechanisms. However, it is not adequate to treat gravitational deposition. In the present work, the ability of the particular method to treat diffusional and convective diffusional depositions relevant to colloid systems is studied in detail.

scholarly journals MODELAGEM PRÉ-COLHEITA DA ESTRUTURA DIAMÉTRICA DE PLANTIOS DE Pinus spp. POR MEIO DE DISTRIBUIÇÕES PROBABILÍSTICAS

FLORESTA ◽  
2012 ◽  
Vol 42 (2) ◽  
pp. 381
Author(s):  
Fernando Da Silva
Keyword(s):  
Method Of Moments ◽  
Least Squares Method ◽  
Timber Harvesting ◽  
Diameter Class ◽  
Chi Square ◽  
Method Of Maximum Likelihood ◽  
Moments Method ◽  
Log Normal ◽  
Pinus Spp

 O objetivo foi estudar o comportamento das curvas de distribuição diamétrica de plantios de Pinus spp. no município de Palmas, PR. Os dados são de um povoamento de 87 ha, com 18 anos de idade. As funções probabilísticas Normal, Log-normal, Gamma, Beta, SB de Johnson, Weibull 2P, Weibull 3P e Weber foram ajustadas, utilizando-se para estimativa dos parâmetros o Método dos Momentos, o Método da Máxima Verossimilhança e o Método de Mínimos Quadrados. A qualidade dos ajustes das distribuições foi avaliada por meio do teste de χ2, adotando 5% de probabilidade e o desvio relativo entre as somas observada e estimada dos diâmetros. Verificou-se a sobreposição das curvas em algumas classes, não sendo possível discriminar qual a melhor distribuição somente observando os histogramas. As curvas foram comparadas analiticamente pelo teste de qui-quadrado (χ2), que revelou diferenças significativas entre as curvas observada e estimada. Procedeu-se à análise dos desvios relativos entre as somas observada e estimada dos diâmetros, apenas para as funções que se mostraram aderentes no teste de χ2. Dentre as funções testadas, Weibull 3P apresentou o melhor desempenho, sendo, portanto, recomendada para a estimar o número de árvores por hectare e por classe diamétrica na região do estudo.Palavras-chave: Manejo florestal; colheita de madeira; modelagem. AbstractPre harvesting modeling of the diametric structure in stands of Pinus spp. using probability density functions. The objective was to study the behavior of the distribution curves diamétric of plantations Pinus spp. in the municipality of Palmas - PR. Data are from a stand of 87 ha, with 18 years of age. The probability functions Normal, Log-normal, Gamma, Beta, Johnson SB, Weibull 2P, 3P Weibull and Weber were adjusted to estimate parameters using the Method of Moments, Method of maximum likelihood and least squares method. The quality of the fits of the distributions was assessed using the χ2 test, with 5% probability and the relative deviation between the observed and estimated sums of the diameters. There was overlap of the curves in some classes, it was not possible to discriminate the best distribution only observing the histograms. The analytical curves were compared using the chi-square (χ2), which revealed significant differences between the observed and estimated curves. There has been analysis of the relative deviations between the observed and estimated sums of the diameters, only for the functions that were adherent in the χ2 test. Among the functions tested, the Weibull 3P function showed the best performance and was recommended to estimate the number of trees per hectare by diameter class in the study region.Keywords: Forest management; timber harvesting; modeling. 

scholarly journals The emerging technology of biohybrid micro-robots: a review

2021 ◽  
Author(s):  
Zening Lin ◽  
Tao Jiang ◽  
Jianzhong Shang
Keyword(s):  
Self Assembly ◽  
Degrees Of Freedom ◽  
High Energy ◽  
Living Cells ◽  
Multiple Degrees Of Freedom ◽  
The Past ◽  
Great Prevalence ◽  
Performance Decline ◽  
High Energy Efficiency ◽  
Living Tissues

Abstract In the past few decades, robotics research has witnessed an increasingly high interest in miniaturized, intelligent, and integrated robots. The imperative component of a robot is the actuator that determines its performance. Although traditional rigid drives such as motors and gas engines have shown great prevalence in most macroscale circumstances, the reduction of these drives to the millimeter or even lower scale results in a significant increase in manufacturing difficulty accompanied by a remarkable performance decline. Biohybrid robots driven by living cells can be a potential solution to overcome these drawbacks by benefiting from the intrinsic microscale self-assembly of living tissues and high energy efficiency, which, among other unprecedented properties, also feature flexibility, self-repair, and even multiple degrees of freedom. This paper systematically reviews the development of biohybrid robots. First, the development of biological flexible drivers is introduced while emphasizing on their advantages over traditional drivers. Second, up-to-date works regarding biohybrid robots are reviewed in detail from three aspects: biological driving sources, actuator materials, and structures with associated control methodologies. Finally, the potential future applications and major challenges of biohybrid robots are explored. Graphic abstract

scholarly journals The limits of normal approximation for adult height

2021 ◽  
Author(s):  
Sergei A. Slavskii ◽  
Ivan A. Kuznetsov ◽  
Tatiana I. Shashkova ◽  
Georgii A. Bazykin ◽  
Tatiana I. Axenovich ◽  
...  
Keyword(s):  
Complex Traits ◽  
Adult Height ◽  
Normal Approximation ◽  
Classical Model ◽  
Model Complexity ◽  
Test Case ◽  
Genetic Studies ◽  
Quantitative Genetic ◽  
Profound Influence ◽  
Log Normal

AbstractAdult height inspired the first biometrical and quantitative genetic studies and is a test-case trait for understanding heritability. The studies of height led to formulation of the classical polygenic model, that has a profound influence on the way we view and analyse complex traits. An essential part of the classical model is an assumption of additivity of effects and normality of the distribution of the residuals. However, it may be expected that the normal approximation will become insufficient in bigger studies. Here, we demonstrate that when the height of hundreds of thousands of individuals is analysed, the model complexity needs to be increased to include non-additive interactions between sex, environment and genes. Alternatively, the use of log-normal approximation allowed us to still use the additive effects model. These findings are important for future genetic and methodologic studies that make use of adult height as an exemplar trait.

scholarly journals Does Neonatal Imitation Exist? Insights From a Meta-Analysis of 336 Effect Sizes

2021 ◽  
pp. 174569162095983
Author(s):  
Jacqueline Davis ◽  
Jonathan Redshaw ◽  
Thomas Suddendorf ◽  
Mark Nielsen ◽  
Siobhan Kennedy-Costantini ◽  
...  
Keyword(s):  
Social Behavior ◽  
Positive Result ◽  
Human Development ◽  
Degrees Of Freedom ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Significant Evidence ◽  
The Past ◽  
Substantial Heterogeneity

Neonatal imitation is a cornerstone in many theoretical accounts of human development and social behavior, yet its existence has been debated for the past 40 years. To examine possible explanations for the inconsistent findings in this body of research, we conducted a multilevel meta-analysis synthesizing 336 effect sizes from 33 independent samples of human newborns, reported in 26 articles. The meta-analysis found significant evidence for neonatal imitation ( d = 0.68, 95% CI = [0.39, 0.96], p < .001) but substantial heterogeneity between study estimates. This heterogeneity was not explained by any of 13 methodological moderators identified by previous reviews, but it was associated with researcher affiliation, test of moderators ( QM) (15) = 57.09, p < .001. There are at least two possible explanations for these results: (a) Neonatal imitation exists and its detection varies as a function of uncaptured methodological factors common to a limited set of studies, and (2) neonatal imitation does not exist and the overall positive result is an artifact of high researcher degrees of freedom.

scholarly journals Multi-stable composite twisting structure for morphing applications

2012 ◽  
Vol 468 (2141) ◽  
pp. 1230-1251 ◽  
Author(s):  
X. Lachenal ◽  
P. M. Weaver ◽  
S. Daynes
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Design Parameters ◽  
Engineering Structures ◽  
The Past ◽  
Wide Range ◽  
Morphing Structure ◽  
Low Mass ◽  
Unstable States

Conventional shape-changing engineering structures use discrete parts articulated around a number of linkages. Each part carries the loads, and the articulations provide the degrees of freedom of the system, leading to heavy and complex mechanisms. Consequently, there has been increased interest in morphing structures over the past decade owing to their potential to combine the conflicting requirements of strength, flexibility and low mass. This article presents a novel type of morphing structure capable of large deformations, simply consisting of two pre-stressed flanges joined to introduce two stable configurations. The bistability is analysed through a simple analytical model, predicting the positions of the stable and unstable states for different design parameters and material properties. Good correlation is found between experimental results, finite-element modelling and predictions from the analytical model for one particular example. A wide range of design parameters and material properties is also analytically investigated, yielding a remarkable structure with zero stiffness along the twisting axis.

scholarly journals Multi-Method END Study in the Search for 'Defects' in an Aeronautical Radar Element

2020 ◽  
Vol 14 (11) ◽  
pp. 19
Author(s):  
Gaston Sanglier ◽  
Jose Miguel ◽  
Jose Antonio Penaranda ◽  
y Gabriel Del Ojo
Keyword(s):  
Partial Information ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
The Past ◽  
New Methods ◽  
New Concepts ◽  
Indispensable Tool ◽  
Inspection Techniques ◽  
Non Destructive

Non-Destructive Testing (NDT) has gone from being a simple laboratory curiosity to an indispensable tool in the industry to determine the level of quality achieved in its products. The new concepts of Integrated Manufacturing (CIM) bring a more universal concept of quality compared to the past philosophy based on Quality Control as a group specialized in checking whether production works within certain specifications. Even so, NDTs have not lost interest, but have seen their interest increased due to automated inspection techniques. It has become a contribution to the structuring of quality as it allows to move from purely empirical criteria to other more objective and that constitute the link between design and evaluation (Ramirez et al, 1996). The work presented, although it does not propose new methods or techniques of NDT, has the interest of converging into a single object five conventional methods each of which provides partial information about their quality of manufacture and must synthesize the results in order to evaluate it. Furthermore, it shows a situation of the application of NDT in which these must be applied in the absence of reference standards, as they do not exist. This peculiar situation is completely different from the usual situation in the use of NDT in the industry, both in manufacturing processes and in maintenance inspections.

scholarly journals The International Consortium of Lithium Genetics (ConLiGen): Achievements and Collaborations

2019 ◽  
pp. 51-52
Author(s):  
U. Heilbronner
Keyword(s):  
Rating Scale ◽  
Lithium Treatment ◽  
Genotype Data ◽  
Response Scale ◽  
International Consortium ◽  
International Effort ◽  
Modern Psychiatry ◽  
The Past ◽  
Lithium Response ◽  
Indispensable Tool

Lithium is an indispensable tool of modern psychiatry. Although it is well-known that response to lithium is a familial trait, available research on pharmacogenetics regarding lithium treatment has, in the past, produced few reproducible results. The Consortium of Lithium Genetics (ConLiGen) was initiated by Thomas G. Schulze and Francis J. McMahon in 2008 to overcome these limitations. To date, researchers from 39 countries have joined the consortium, making it a truly international effort. A hallmark of the consortium is the use of an 11-point lithium response rating scale defined by Martin Alda and colleagues. The pooling of genotype data from over 2,500 patients phenotyped with this standardized response scale, have led to initial successes, which form the basis for further research.

scholarly journals Kinetic electronics: Monolithic processing of a layered flexible robotic actuator film for simple film microrobot fabrication

2021 ◽  
Author(s):  
Shiyi Zhang ◽  
Joseph Wang ◽  
Kenshi Hayashi ◽  
Fumihiro Sassa
Keyword(s):  
Mass Production ◽  
Degrees Of Freedom ◽  
Complex Structure ◽  
Robotic Systems ◽  
Durability Test ◽  
Electrical Circuits ◽  
Multiple Degrees Of Freedom ◽  
The Past ◽  
Cmos Compatible ◽  
Simple Film

Abstract Low-invasive soft robotic techniques can potentially be used for developing next-generation body–machine interfaces. Most soft robots require complicated fabrication processes involving 3D printing and bonding/assembling. In this letter, we describe a monolithic soft microrobot fabrication process for the mass production of soft film robots with a complex structure by simple 2D processing of a robotic actuator film. The 45 μg/mm^2 lightweight film robot can be driven at a voltage of CMOS compatible 5 V with 0.15 mm^-1 large curvature changes; it can generate a force 5.7 times greater than its self-weight. In a durability test, actuation could be carried out over 8000 times without degradation. To further demonstrate this technique, three types of film robots with multiple degrees of freedom and moving illuminator robot were fabricated. This technique can easily integrate various electrical circuits developed in the past to robotic systems and can be used for developing advanced wearable sensing devices; It can be called “Kinetic electronics.”

scholarly journals Simulation of mineral dust aerosol with piecewise log-normal approximation (PLA) in CanAM4-PAM

2011 ◽  
Vol 11 (9) ◽  
pp. 26477-26520
Author(s):  
Y. Peng ◽  
K. von Salzen ◽  
J. Li
Keyword(s):  
Climate Model ◽  
Normal Approximation ◽  
Global Climate ◽  
Global Climate Model ◽  
Dust Aerosol ◽  
Radiative Properties ◽  
Fourth Generation ◽  
Surface Measurements ◽  
Log Normal ◽  
Year 2000

Abstract. A new size-resolved dust scheme based on the numerical method of piecewise log-normal approximation (PLA) was developed and implemented in the fourth generation of the Canadian Atmospheric Global Climate Model with the PLA Aerosol Module (CanAM4-PAM). The total simulated annual mean dust burden is 37.8 mg m−2 for year 2000, which is consistent with estimates from other models. Results from simulations are compared with multiple surface measurements near and away from dust source regions, validating the generation, transport and deposition of dust in the model. Most discrepancies between model results and surface measurements are due to unresolved aerosol processes. Radiative properties of dust aerosol are derived from approximated parameters in two size modes using Mie theory. The simulated aerosol optical depth (AOD) is compared with several satellite observations and shows good agreements. The model yields a dust AOD of 0.042 and total AOD of 0.126 for the year 2000. The simulated aerosol direct radiative forcings (ADRF) of dust and total aerosol over ocean are −1.24 W m−2 and −4.76 W m−2 respectively, which show good consistency with satellite estimates for the year 2001.

Modelling and Simulation of a Isoglide T3R1 Parallel Robot

2010 ◽  
Vol 166-167 ◽  
pp. 457-462
Author(s):  
Dan Verdes ◽  
Radu Balan ◽  
Máthé Koppány
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Practical Implementation ◽  
Medical Robots ◽  
The Past ◽  
And Control ◽  
Workspace Design ◽  
Human Systems

Parallel robots find many applications in human-systems interaction, medical robots, rehabilitation, exoskeletons, to name a few. These applications are characterized by many imperatives, with robust precision and dynamic workspace computation as the two ultimate ones. This paper presents kinematic analysis, workspace, design and control to 3 degrees of freedom (DOF) parallel robots. Parallel robots have received considerable attention from both researchers and manufacturers over the past years because of their potential for high stiffness, low inertia and high speed capability. Therefore, the 3 DOF translation parallel robots provide high potential and good prospects for their practical implementation in human-systems interaction.

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