Construction Solutions of Ordinary and Partial Differential Equations using the Analytical and Numerical Methods

In this paper we studied the solution of partial differential equations using numerical methods. The paper includes study of the solving partial differential equations of the type of parabolic, elliptic and hyperbolic, and the method of the net was used for the numerical nods, which represents a case of finite differences. We have two types of solution which are the internal solution and boundary solution. The internal solution is based on the internal nodes of the net. The boundary solution depends on the boundary nodes of the net, in addition to finding the analytical solution of the equations to compare the results. We also discussed solving the problem of Laplace, Poisson, for the importance of these equations in the applied side; Mat lab was used to find the values of tables for the values of border differences. We have derived a new formula for the solution of partial differential equations containing three independent variables.

Surface Coating of Cyclotetramethylenetetranitramine (HMX) Particles and Its Property Investigation

To improve the safety of cyclotetramethylenetetranitramine (HMX) particles, the polymer thermoplastic polyurethane elastomer (TPU) and nitrocellulose (NC) were introduced to coat HMX powder by water-solution suspension method and internal solution method, respectively. Scanning electron microscope (SEM) and X-ray photo-electron spectrometry (XPS) were employed to characterize the HMX samples and the role of NC and TPU in the coating processes were discussed. The impact sensitivity, friction sensitivity, and the thermal decomposition of coated HMX particles were investigated, and compared to the unprocessed ones. The results indicate that both TPU and NC can improve the wetting ability of the coating materials on HMX surface and reinforce the connection between HMX and the coating materials. The impact sensitivity and friction sensitivity of HMX samples decrease obviously after they have been surface coated; the drop height (H50) is increased from 35.24 cm to 50.08 cm, and the friction probability is reduced from 93.2 % to 58.3%. The activation energy (Ea) and the self-ignition temperature increase by 10.46 KJ·mol-1 and 1.8, respectively.

Lightsticks cause adverse effects on behavior and mortality of marine mysids Promysis atlantica

Lightsticks baits are discharged into the ocean after their use in longline fishing. The traditional Brazilian community of Costa dos Coqueiros, Bahia, uses lightsticks as a medicine for rheumatism, vitiligo, and mycoses. It may affect marine life when its content leak into the ocean. This study assessed the toxicity identification and evaluation (TIE) of lightsticks constituents on marine mysids Promysis atlantica. The internal solution was dissolved in seawater with ethanol. The lethal concentration of the contaminant that causes mortality in 50% of the exposed population (LC50) after 3h was 0.001%, demonstrating that lightstick is exceptionally toxic because low concentrations cause mortality to mysids P. atlantica. Due to lightsticks' high toxicity, the TIE baseline was 0.005% SSE (stock solution ethanol), and the selected endpoints were behavior and lethality. The sample submitted to aeration presented a significant reduction (P < 0.05) in toxicity (0.005% SSE) because the volatile compounds caused the toxic effect. The sodium thiosulfate treatment induced an insignificant decrease in toxicity. Thus, a new assay was conducted considering aeration and sodium thiosulfate. This combination reduced lightstick toxicity compared to the baseline lightstick, suggesting that volatile compounds and oxidants were responsible for toxicity; even in low concentrations, lightstick can promote significant behavior changes and deleterious effects. It is recommended to create new mechanisms to inspect fishing vessels, thus avoiding the improper disposal of attractors at sea and common garbage.

Effect of Sulfate Crystallization on Sandstone in the Yungang Grottoes

Subjected to various weathering in nature over long time, sandstone has been deteriorated in the Yungang Grottoes. The repeated dissolution and crystallization of soluble salts are important factors that cause the deterioration of the grotto sandstone. In order to study the action mechanism of sulfate crystallization in the Yungang Grottoes sandstone, deterioration tests were carried out by the “soaking-evaporation” cycle of saturated magnesium sulfate (MgSO4) and saturated sodium sulfate (Na2SO4) solutions in laboratory. The test results show that the participation of sulfate greatly accelerated the weathering speed of sandstone. The ultrasonic velocity of the specimens circulated in both Na2SO4 and MgSO4 solutions show a trend of first increasing and then decreasing, and changes more obviously in Na2SO4 solution. In the evaporation stage of the circulation, the peeling mass of the specimens circulated in Na2SO4 solution is significantly greater than that in MgSO4 solution. From the evaporation tests on saturated Na2SO4 and MgSO4 solutions and observation with optical microscope and scanning electron microscope, it is found that a dense crystal layer was formed on the surface during the evaporation of saturated MgSO4 solution, and it gradually seals the internal solution, slowing down the further evaporation. During the solution evaporation, Na2SO4 crystallizes into powdery crystals in a flocculent and soft state, and there are pores between the crystal grains. The change in the ultrasonic velocity of specimens in the "soaking-evaporation" cycle tests can be explained by the evaporation test results.

Re-Assessing the Evidentiary Threshold for Zinā’ in Islamic Criminal Law: A De Facto Exemption Proposal

This article considers the four eyewitness threshold for zinā’ in Islamic criminal law. In some Muslim-majority countries where zinā’ remains an offence, judiciaries have by-passed the threshold by accepting singular confessions from male fornicators or, otherwise, inferring fornication from pregnancy outside of marriage. As a result, a disproportionate number of women have been prosecuted, convicted, and even punished for zinā’. I assert that the four-eyewitness threshold allows for an alternative way to view zinā’ that can result in a different set of consequences. If the threshold is taken seriously such that it becomes the only evidentiary basis upon which a zinā’ conviction can be entered, it will create an effective or de facto exemption where alleged perpetrators can never be convicted, except in the rarest cases where four independent eyewitnesses can be corralled. If adopted, this approach would provide a principled basis to reject opportunistic confessions that deflect punishment to accused female fornicators. And as an ‘internal’ solution that arises within the framework of the sharī’a, a de facto exemption approach is more likely to be perceived as legitimate when compared with proposed solutions that find their basis in international human rights legal instruments.

Indirect Drying and Coking Characteristics of Coking Coal with Soda Residue Additive

To improve indirect drying efficiency, the effect of soda residue on the drying characteristics of coking coal were studied using a self-made indirect drying system. A tube furnace was used in the dry distillation of coal samples with soda residue, and the coke properties were analyzed. The results indicated that the soda residue has a significant influence on the increase in the heating rate of coal samples in the temperature distribution range of 90 to 110 °C. With the addition of 2%, 5%, and 10% soda residue, the drying rates increased by 11.5%, 25.3%, and 37.3%, respectively at 110 °C. The results of dry distillation show that addition of 2%, 5% and 10% soda residue decreases the carbon loss quantity by 4.67, 4.99, and 8.82 g, respectively. The mechanical strength of coke samples satisfies the industrial conditions when the soda residue ratio ranges from 2% to 5%. Soda residue can improve the active point of coke dissolution reaction and inhibit coke internal solution. Economically, coking coal samples mixed with soda residue have an obvious energy saving advantage in the drying process. Energy saving analysis found that it can reduce cost input by 20% than that of the normal drying method.

Adsorption of Anthocyanins by Cation and Anion Exchange Resins with Aromatic and Aliphatic Polymer Matrices

This study examines the mechanisms of adsorption of anthocyanins from model aqueous solutions at pH values of 3, 6, and 9 by ion-exchange resins making the main component of heterogeneous ion-exchange membranes. This is the first report demonstrating that the pH of the internal solution of a KU-2-8 aromatic cation-exchange resin is 2-3 units lower than the pH of the external bathing anthocyanin-containing solution, and the pH of the internal solution of some anion-exchange resins with an aromatic (AV-17-8, AV-17-2P) or aliphatic (EDE-10P) matrix is 2–4 units higher than the pH of the external solution. This pH shift is caused by the Donnan exclusion of hydroxyl ions (in the KU-2-8 resin) or protons (in the AV-17-8, AV-17-2P, and EDE-10P resins). The most significant pH shift is observed for the EDE-10P resin, which has the highest ion-exchange capacity causing the highest Donnan exclusion. Due to the pH shift, the electric charge of anthocyanin inside an ion-exchange resin differs from its charge in the external solution. At pH 6, the external solution contains uncharged anthocyanin molecules. However, in the AV-17-8 and AV-17-2P resins, the anthocyanins are present as singly charged anions, while in the EDE-10P resin, they are in the form of doubly charged anions. Due to the electrostatic interactions of these anions with the positively charged fixed groups of anion-exchange resins, the adsorption capacities of AV-17-8, AV-17-2P, and EDE-10P were higher than expected. It was established that the electrostatic interactions of anthocyanins with the charged fixed groups increase the adsorption capacity of the aromatic resin by a factor of 1.8–2.5 compared to the adsorption caused by the π–π (stacking) interactions. These results provide new insights into the fouling mechanism of ion-exchange materials by polyphenols; they can help develop strategies for membrane cleaning and for extracting anthocyanins from juices and wine using ion-exchange resins and membranes.

Unintended Changes of Ion-Selective Membranes Composition—Origin and Effect on Analytical Performance

Ion-selective membranes, as used in potentiometric sensors, are mixtures of a few important constituents in a carefully balanced proportion. The changes of composition of the ion-selective membrane, both qualitative and quantitative, affect the analytical performance of sensors. Different constructions and materials applied to improve sensors result in specific conditions of membrane formation, in consequence, potentially can result in uncontrolled modification of the membrane composition. Clearly, these effects need to be considered, especially if preparation of miniaturized, potentially disposable internal-solution free sensors is considered. Furthermore, membrane composition changes can occur during the normal operation of sensors—accumulation of species as well as release need to be taken into account, regardless of the construction of sensors used. Issues related to spontaneous changes of membrane composition that can occur during sensor construction, pre-treatment and their operation, seem to be underestimated in the subject literature. The aim of this work is to summarize available data related to potentiometric sensors and highlight the effects that can potentially be important also for other sensors using ion-selective membranes, e.g., optodes or voltammetric sensors.

A Framework for Understanding Information Practice

This chapter presents a framework for understanding information practice. In the language of social science, the “dependent variable” is information practice, which coordinates an organization's representations with its world. Practice itself is an intervening process that shapes military innovation and battlefield performance. The “independent variables” are the external problems posed by the operational environment and the internal solution adopted by the military organization. The basic argument is that the interaction between operational problems and organizational solutions gives rise to four different patterns of information practice, two of which improve and two of which undermine performance. Ultimately, an information system should be understood as not just the computing devices and software applications in an organization, but also the people and processes that generate, transform, and communicate information.