Prediction of the reactivity of oleum sulfonating agents upon carbamide sulfonation

In this work, a research of the reactivity of sulfonating agents of oleum during sulfonation of carbamide was carried out. Cation HSO3+ and sulfur trioxide in monomeric, dimeric, and trimeric forms were chosen as sulfonating agents. The modeling was carried out by the density functional theory (B3LYP5/aug-cc-pVDZ) and the second-order Möller-Plesset perturbation theory (MP2/aug-cc-pVDZ). Simulation was carried out in a vacuum and a polar solvent, which was taken as 100% sulfuric acid. The solvent was taken into account using the COSMO model. The evaluation of the reactivity of sulfonating agents was carried out on the basis of molecular modeling of sulfonating agents and carbamide. The reactivity descriptors were chosen as the reactivity criteria, such as: energies and the location of the highest occupied molecular orbital and lowest unoccupied molecular orbital, charges on atoms, molecular electrostatic potential, absolute hardness and electrophilicity index. It was determined that carbamide is a fairly hard Lewis base, the absolute hardness in vacuum is 6.072, and in a solvent it is 6.635, so charge control is preferable for its sulfonation reaction. Based on this, the greatest preference in the analysis of reactivity indices was given to atomic charges and molecular electrostatic potential. According to the results of the analysis, it was revealed that the highest activity of the studied sulfonating agents is possessed by cation HSO3+, as it has the highest partial charges on atoms (+3.29 in vacuum, +3.38 in a solvent), has the highest electrophilicity (13.45 in a vacuum, 5.35 in a solvent) and does not have steric hindrance factor in contact with the carbamide molecule. Among the forms of sulfur trioxide, preference can be given to both monomeric (highest activity, but there are steric hindrance factor) and trimeric (least steric hindrance factor).

A Metrics-Based Fuzzy Logic Model for Predicting the Reusability of Object-Oriented Software

Software reusability facilitates the engineering of new software or systems functionalities without having to start coding from scratch. This software quality provides numerous merits to the software developers including coming up with larger systems within a short time, with reduced development cost and reduced developer effort. However, software reusability is an external software quality attribute that is not measurable directly, and this is a major hindrance factor to its adoption in the software engineering process. This indicates that there is a need to come up with an approach to measure or predict software reusability to give advisories to the software developers on the prediction of software reusability. Therefore, this study aims at coming up with a prediction model to estimate software reusability by employing the use of a fuzzy logic approach, the study focused on Object-Oriented software. The research followed a guideline of four objectives and assumed descriptive and diagnostic methodology. It started by considering the existing ISO/IEC 25010 software quality model to determine and describe the main factors affecting the reusability of Object-Oriented software. The main factors identified were Abstraction, Cohesion and Coupling, thereafter, it was followed by the definition of metrics to measure each of the three factors identified, to operationalize these metrics, they were then validated using Weyuker’s nine properties. After this, the researchers developed a metrics tool to automate the process of computing the metrics values of the defined metrics. Finally, a fuzzy logic prediction model that predicts the reusability of Object-Oriented software was developed based on the metrics values computed by the metrics tool. This model was then validated using the Analytical Hierarchical Process (AHP) framework. The outcome of the four objectives was presented, discussed and future works of this study outlines. This research work is a contribution to the software development industry where the software developers can apply it to engineer reusable software.

Research on the Psychological Model of Free-floating Bike-Sharing Using Behavior: A Case Study of Beijing

As a clean, sustainable transport tool, bicycles have significant advantages in short-distance travel. Despite many efforts assumed in Beijing to improve the cycling environment, the popularity of cycling remains relatively low. However, the advent of the free-floating bike-sharing (FFBS) system has engendered an unexpected cycling enthusiasm in Beijing. Therefore, it is of great importance to delve into why travelers prefer FFBS as a transportation form from a psychological perspective. In this paper, 352 valid questionnaires were collected from an online survey, and an extended theory of planned behavior (TPB) was adopted to examine the psychological determinants of intention and actual behavior to use FFBS. The results showed that men and car-owners prefer vehicles and show a lower willingness to use FFBS. In contrast, residents under the age of 60, residents with FFBS riding experience, and residents skilled in cycling are inclined to use FFBS; the economic convenience of FFBS is the most important attractant for FFBS, while bad weather is the biggest hindrance factor for residents to use FFBS; however, imperfection in infrastructure has no significant impact on reducing residents’ willingness to use FFBS. These results have important implications for planners to better understand the FFBS use behavior, and several suggestions are proposed to support the policymaking about FFBS.

Theoretical studies on Alpha decay half-lives of Astatine isotopes

The half-life of a parent nucleus of Astatine isotopes [Formula: see text] decaying via alpha emission is investigated by employing Coulomb and proximity potential model (CPPM) using the WKB barrier penetration probability and other different analytical and semiempirical formulae of Royer, AKRE, Akrawy, RoyerB, MRoyerB, MRenB, SemFIS, VS and SLB. In the calculation of Alpha decay (AD) half-life the available experimental and theoretical [Formula: see text]-values with the total alpha kinetic energy have been considered. The behavior of hindrance factor with the variation of mass numbers of parent nuclei for isotopes in the range [Formula: see text] and the effect of magic number at closed shells were investigated. Through the comparison of obtained results from the systematics with the experimental data, the prediction of SemFIS formula was the best among the studied ones where it shows the minimum standard deviation of 0.829881.

The Policy Implementation Impact on Region Management

The land function alteration happens massively at Kecamatan Cimenyan, an area in North Bandung Region or known as Kawasan Bandung Utara (KBU). KBU areas are important because it is located traverse 4 different regions, such as Bandung, Kabupaten Bandung, Kabupaten Bandung Barat, and Cimahi. The main function KBU areas to the cities and districts are very important, especially for water infiltration. It means that these areas are become the main water conservation land and also a flooding prevention area, not only for Bandung Raya region, but also for West Java Region. Land function alteration that happen in Kecamatan Cimenyan are encompass forest, plantation, dry land agricultural plant or known as TPLK conversion and water conservation land alteration into housing development, hotel chain business, and even change into mining area. That leads to environmental changes, such as soil erosion and sedimentation, overflowing river that leads to floods. It’s all because the water conservation areas are getting smaller and smaller each day. Thus, this research aimed to analyse the policy implementation factors that affect the region management effectiveness, hindrance factor, and also the administration efforts at Kecamatan Cimenyan Kabupaten Bandung. An explanative method was used to analyse this research, and used cluster sampling to select the sample from 9 village and kelurahan in KBU region, Kecamatan Cimenyan Kabupaten Bandung in particular. And on every stage sampling are taken by simple random sampling method. The data of this research are examine using structure equation modelling (SEM), a procedure based on methods of successive interval. This research disclosed that the policy implementation that based on communication dimension, resources, disposition/support attitude and bureaucratic structure have a significant impact on the region management effectiveness. And the most significant dimension to determine the effectiveness of the region management was support/disposition dimension then followed by others dimension.

Mass Transport Through Interstitial Structures

Interstitial space, also called interstitum, separating the vital organs of a human body, is the primary source of lymph and is a major fluid compartment in the body. Interstitial space (IS) is filled out by thick collagen (CL) bundles which form lattices represented by a network of capillaries. This network has the structure similar to a sponge porous matrix (SPM) with pores-capillaries of variable cross-section. To analyse the mass transport of interstitial fluids (IFs) through the porous matrix it is assumed that the SPM is composed of an irregular system of pores which may be modelled as a fractal porous matrix. The interstitial fluids can be either bio-suspensions or bio-solutions and therefore they have to be modelled as non-Newtonian fluids. Analysing the fluid flow through the porous matrix it is assumed that the SPM is modelled as capillary tubes of variable radii. Introducing a hindrance factor allowed us to consider the porous matrix as a system of fractal capillaries but of constant radii. Classical and fractal expressions for the flow rate, velocity and permeability are derived based on the physical properties of the capillary model of interstitial structures. Each parameter in the proposed expressions does not contain any empirical constant and has a clear physical meaning, and the proposed fractals models relate the flow properties of the fluids under consideration with the structural parameters of interstitium as a porous medium.

Semi-classical calculations of the α decay half-lives for even–even nuclei

The half-lives of the [Formula: see text] decay for even–even nuclei having [Formula: see text] (164 nuclei) have been calculated by using the Wentzel–Kramers–Brillouin (WKB) method together Bohr–Sommerfeld (BS) quantization condition for cosh potential in two-different forms with and without the isospin effects for six different parameter sets. By comparing the obtained results with the experimental values, the rms deviations have been computed. It is obtained that when the cosh potential is used in 2 different type forms, the rms values are also changed and the better one for obtaining the half-lives is cosh-2 form. Even if the isospin-dependent potential does not have so much effect on rms values in this sort of WKB with BS calculations with cosh potential forms, considering the isospin effect together the isospin-dependent nuclear diffuseness parameter have a strong influence on the rms values. New hindrance factor formula based on liquid drop model was used in order to show the influence of hindrance factor on the [Formula: see text] decay half-lives. It is pointed out that this new function of the hindrance factor does not depend on the magic numbers, it contains fewer free parameters and using of this improves the calculations positively. New estimates by using present model have also been made for even–even nuclei having with [Formula: see text] which do not have the measured [Formula: see text] decay half-lives yet and they have been compared the results of the ImSahu model. The present results would provide useful information and knowledge for the explanation of half-lives of [Formula: see text] decay of nuclei and future possible experimental studies.

Drug Diffusion Transport Through Human Skin

The stratum corneum (SC) forms the outermost layer of the human skin and is essentially a multilamellar lipid milieu punctuated by protein-filled corneocytes that augment membrane integrity and significantly increase membrane tortuosity. The lipophilic character of the SC, coupled with its intrinsic tortuosity, ensure that it almost always provides the principal barrier to the entry of drug molecules into the organism. Drugs can be administered either as suspensions or as solutions and the formulation can range in complexity from a gel or and ointment to a multilayer transdermal path. In this paper, we discuss theoretical principles used to describe transdermal release and we show that relatively simple membrane transport models based on the appropriate solution to the Fick’s second law of diffusion can be used to explain drug release kinetics into such a complex biological membrane as the human skin. To apply the Fick’s law we introduced into our considerations a brick-and-mortar model with two factors of tortuosity. Assuming that the mortar thickness is variable we also introduced the hindrance factor allowing us to model this variability. Having the modified Fick’s equation we presented its general solution and two special cases of this solution frequently applicable in permeation experiments. It seems that the solutions presented herein better approximate the real conditions of drug delivery then these well known.

Neutrino-induced reactions in core-collapse supernovae: Effects on the electron fraction

Neutrino-induced reactions are a basic ingredient in astrophysical processes like star evolution. The existence of neutrino oscillations affects the rate of nuclear electroweak decays which participates in the chain of events that determines the fate of the star. Among the processes of interest, the production of heavy elements in core-collapse supernovae is strongly dependent upon neutrino properties, like the mixing between different species of neutrinos. In this work, we study the effects of neutrino oscillations upon the electron fraction as a function of the neutrino mixing parameters, for two schemes: the [Formula: see text]-scheme (one active neutrino and one sterile neutrino) and the [Formula: see text]-scheme (two active neutrinos and one sterile neutrino). We have performed this analysis considering a core-collapse supernovae and determined the physical conditions needed to activate the nuclear reaction chains involved in the r-process. We found that the interactions of the neutrinos with matter and among themselves and the initial amount of sterile neutrinos in the neutrino-sphere might change the electron fraction, therefore affecting the onset of the r-process. We have set constrains on the active-sterile neutrino mixing parameters. They are the square-mass-difference [Formula: see text], the mixing angle [Formula: see text], and the hindrance factor [Formula: see text] for the occupation of sterile neutrinos. The calculations have been performed for different values of [Formula: see text], which is the fraction of [Formula: see text]-particles. For [Formula: see text] the r-process is taking place if [Formula: see text], [Formula: see text] and [Formula: see text]. For larger values of [Formula: see text] the region of parameters is strongly reduced. The present results are compared to results available in the literature.