scholarly journals Charge distribution functions for characterization of complex systems

2021 ◽  
Vol 12 (1) ◽  
pp. 3-8
Author(s):  
V. M. Gun’ko ◽  

A set of characteristics calculated within the scope of quantum chemistry methods may be assigned to local ones changing from atom to atom in complex systems. Simple averaging of the related values gives rather poor characteristics of the systems because various fractions of certain atoms can have different surrounding and, therefore, different characteristics, which may not correspond to the average one. The aim of this study is searching a more appropriate pathway to transform local characteristics, e.g., atomic charges, into nonlocal ones based on the distribution functions. The distribution functions of atomic charges (CDF) could be considered as a simple tool to analyze nonuniform complex systems since specificity of different fractions of atoms reflects in the CDF shape. As a whole, the approach accuracy and efficiency depend on the quality and appropriateness of molecular and cluster models used, as well as on the quantum chemical methods (ab initio, DFT, and semiempirical) and the basis sets used. Nanosystems with dozens of molecules (clusters, domains, nanodroplets), modelling a liquid phase or interfacial layers, and solid nanoparticles of almost real sizes (> 40 units, > 2 nm) may be considered as more appropriate models of real systems than the models with several molecules and small clusters (< 20 units, < 1 nm). This approach has been applied to a set of representatives of such various materials as activated carbon, porous and nanoparticulate silicas unmodified and modified interacting with nitrogen, methane, water, human serum albumin (HSA) binding doxorubicin molecules. This approach may give information useful upon the analysis of any complex system.

1989 ◽  
Author(s):  
Daniel Bensen ◽  
Michael Welge ◽  
Alfred Huebler ◽  
Norman Packard

Author(s):  
Stefan Thurner ◽  
Rudolf Hanel ◽  
Peter Klimekl

Scaling appears practically everywhere in science; it basically quantifies how the properties or shapes of an object change with the scale of the object. Scaling laws are always associated with power laws. The scaling object can be a function, a structure, a physical law, or a distribution function that describes the statistics of a system or a temporal process. We focus on scaling laws that appear in the statistical description of stochastic complex systems, where scaling appears in the distribution functions of observable quantities of dynamical systems or processes. The distribution functions exhibit power laws, approximate power laws, or fat-tailed distributions. Understanding their origin and how power law exponents can be related to the particular nature of a system, is one of the aims of the book.We comment on fitting power laws.


2017 ◽  
Vol 19 (25) ◽  
pp. 16765-16774 ◽  
Author(s):  
Margarita Albertí ◽  
Anna Amat ◽  
Antonio Aguilar ◽  
Fernando Pirani

The present paper focuses on the characterization of the properties of methanol and water molecules in gas and liquid enviroments.


2019 ◽  
Vol 32 (1) ◽  
pp. 1-6
Author(s):  
Nikita Verma

As a disease skin cancer has obtained different characteristics over the decades. Solar radiation that contains ultraviolet ray is the prime cause of skin cancer. In this present research, the nano-precipitation method was applied for preparing Quercetin loaded Nanoparticle (Qu-Nps) with much enhanced loading properties and improves incorporation of corresponding drugs. At the same time, the Quadratic model that takes help of the Response Surface Method was applied to observe the effects of some specific parameters maintained in the development of nanoparticle. Here, the sonication time was 20 min and delivery system F6 (with Drug: Polymer ratio of 1:45) provided optimum drug entrapment ability which is 70%. The optimized formulation for average size was almost 102.39 ±7.64 nm with zeta potential diameter averaging -28.43mV. Quercetin is a dietary flavonoid possessing multidimensional properties that is used in various other diseases including viral infection, bacterial infection, diabetes mellitus, and cancer. All outcomes support the view that Quercetin loaded nanoparticles (Qu-Nps) has high entrapment and drug loading abilities.


2012 ◽  
Vol 32 (1) ◽  
pp. 26-33 ◽  
Author(s):  
Robson de Jesus Mascarenhas ◽  
Silvanda de Melo Silva ◽  
Maria Auxiliadora Coêlho de Lima ◽  
Rejane Maria Nunes Mendonça ◽  
Heinz Johann Holschuh

The objective of this study was to characterize and correlate maturity and quality of the first varieties of Brazilian seedless grapes 'BRS Clara', 'BRS Linda', 'BRS Morena', and 'Advanced Selection 8' compared with the American variety 'Crimson Seedless' in compliance with the Brazilian Normative/2002 and export standards Advanced Selection 8' is dark reddish, has large clusters, and is a very large ellipsoid berry; 'BRS Morena' is black with medium sized clusters and large berry shaped as ellipsoid to globoid; 'BRS Linda' is light green and has large sized clusters; 'Crimson' is pink and has small clusters with berries varying from medium to large sizes and ellipsoid shaped; and 'BRS Clara' is green yellowish has medium sized clusters and small berry of elongated ellipsoid shape. All varieties evaluated meet the standard for domestic market established as berry size minimum diameter 12 mm. 'BRS Clara' does not meet the export requirements of diameter. Berries of the red grapes 'BRS Morena' and 'Crimson Seedless' are firmer. The pH, titratable acidity, and soluble solids meet the official standards. Larger clusters are less acidic and present higher soluble solids/titratable acidity ratios implying that they are the sweetest type when ripe.


1989 ◽  
Vol 83 (1) ◽  
pp. 221-240 ◽  
Author(s):  
JOHN HAPPEL ◽  
PETER H. SELLERS

2009 ◽  
Vol 15 (S3) ◽  
pp. 39-40
Author(s):  
A. Lobo-da-Cunha ◽  
I. Ferreira ◽  
G. Calado

AbstractCephalaspideans are a group of opisthobranch gastropods comprising carnivorous and herbivorous species, allowing an investigation of the relationship between these diets and the morphofunctional features of the salivary glands.In this study, the salivary glands of the carnivorous cephalaspidean Philinopsis depicta were observed by light microscopy using semithin sections and by transmission electron microscopy. A central duct runs along the length of these thin ribbon-shaped glands dividing them in two halves, each formed by a single row of tubules perpendicularly attached to the central duct. The simple epithelium of the central duct and lateral tubes contains ciliated cells and two types of secretory cells, named granular cells and cells with apical vacuole (Fig. 1). A very thin outer layer of connective tissue covers the epithelium (Fig. 1). The ciliated cells are numerous but very thin, forming small clusters between secretory cells. The nucleus, several mitochondria and a few lysosomes are located in the apical region were the cells are wider. A very thin cytoplasmic stalk reaches the base of the epithelium and contains bundles of filaments in addition to some mitochondria.


Author(s):  
Amin Moniri-Morad ◽  
Mohammad Pourgol-Mohammad ◽  
Hamid Aghababaei ◽  
Javad Sattarvand

Operational heterogeneity and harsh environment lead to major variations in production system performance and safety. Traditional probabilistic model is dealt with time-to-event data analysis, which does not have the capability of quantifying and simulation of these types of complexities. This research proposes an integrated methodology for analyzing the impact of dominant explanatory variables on the complex system reliability. A flexible parametric proportional hazards model is developed by focusing on standard parametric Cox regression model for reliability evaluation in complex systems. To achieve this, natural cubic splines are utilized to create a smooth and flexible baseline hazards function where the standard parametric distribution functions do not fit into the failure data set. A real case study is considered to evaluate the reliability for multi-component mechanical systems such as mining equipment. Different operational and environmental explanatory variables are chosen for the analysis process. Research findings revealed that precise estimation of the baseline hazards function is a major part of the reliability evaluation in heterogeneous environment. It is concluded that an appropriate maintenance strategy potentially mitigate the equipment failure intensity.


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