Stability Analysis of Implicit-Explicit Class for Solving ODEs and DDEs

Implicit-Explicit schemes have been widely used, it reduces the computational work for solving differential equations which have both stiff and non-stiff parts . In this paper an implicit-explicit linear multistep method for solving ordinary and delay differential equations is introduced. In both cases we are going to study the stability of the method using two approaches and the stability regions will be ploted. Numerical tests are introduced

Quantum Chemical Study on the Corrosion Inhibition of Copper Using Some Thiosemicarbazides and Tetrazoles

Relationships between corrosion inhibition efficiency of two thiosemicarbazide based compounds namely; 4-phenyl thiosemicarbazide (PTSC), Salicylaldehyde thiosemicarbazone (STSC) and 4 tetrazole derivative; 5-Mercapto-1-methyltetrazole (MMTA), 5-(3-Pyridyl)-1H-tetrazole (PyTA), 5-Amino-tetrazole mono hydrate (ATA) and 5-phenyl tetrazole (PTA) and their molecular electronic properties have been theoretically studied at the level .............(More details are available in the full paper) Keywords: Thiosemicarbazides and Tetrazoles, structural parameters DOI: 10.7176/CMR/11-2-04

Electroless Plating of Ni-B Composite Coating on AZ31 Mg alloy

A Ni–B coating was electroless-deposited directly on H3PO4/HF pickled AZ31. The thickness of the plating layer was estimated through weight gain measurements and was affected by temperature, time and bath composition. The highest thickness was obtained at 6 g/L of NaHB4 at 85oC.  An adherent compact layer of Ni-B was obtained. Electrochemical impedance spectroscopy measurements in 3.5 wt.% sodium chloride aqueous solution suggest that the plating can protect the magnesium alloy substrate from corrosion attack

Corrosion Inhibition of Copper in Sea Water Using Derivatives of Thiosemicarbazides

Three corrosion inhibitors namely: 4-allyl-3-thiosemicarbazide C4H9N3 S, 4-(1-methyl)-3-thiosemicarbazide,4-tolyl-3-thiosemicarbazide were tested as corrosion inhibitors for copper in sea water environmnt.Copper samples were tested using potentiodynamic polarization technique in the absence and in the presence of corrosion inhibitors.   High inhibition efficiencies (≥95%) were shown by the tested inhibitors.  The best performance was shown by 4-tolyl-3-TSC

Effect of Pickling and Activation Treatments on the Performance of Electroless Plating of Ni-B Coating on AZ31 Mg Alloy

Pickling is particularly critical before Ni-B electroless plating to create a uniform and catalytically active surface.  In the present work, pickling treatment of AZ31 Mg alloy was performed in phosphoric acid followed by immersion in 40% HF.  The effect of concentration of both H3PO4 and HF as well as the effect of time were investigated.   The pickled samples were then electroless plated with a Ni-B composite.  The performance of the Ni-B composite coating was investigated under the SEM.Results show that the highest quality coating was obtained upon pickling AZ31 Mg alloy samples in 50% phosphoric acid for 1 min, followed by activation in 40% HF for 15 min. Higher concentration of H3PO4 results in a higher concentration of PO3−4, leading to a higher tendency to produce insoluble films (mainly Mg3(PO4)2 and AlPO4) on the substrate surface slowing down the rate of Mg alloy oxidization and dissolution.  Activation of pickled AZ31 Mg samples in HF results in the formation of corrosion resistant dense layer of magnesium fluoride. SEM investigation predicted the electroless deposition of an adherent compact layer of Ni–B composite coating on the H3PO4/HF pickled AZ31 samples. Key Words: AZ31 Mg alloy, pickling, activation, HF, electroless plating DOI: 10.7176/CMR/11-5-04 Publication date:May 31st 201

Temperature dependence growth of CdO thin film prepared by spray pyrolysis

AbstractCdO thin films prepared by spray pyrolysis technique show temperature dependence growth when the spray time is constant. In contrast, the growth is film thickness dependent when the substrate temperature is constant. The films are polycrystalline in the covered spray time and substrate temperature ranges. The crystallite size and microstrain are calculated and analyzed. The Atomic Force Microscopy (AFM) micrographs prove that the grains are uniformly distributed within the scanning areas (5μm×5μm) and (50μm×50μm). The roughness shows a considerable decrease with substrate temperature. All samples show an abrupt change in transmission which indicates a direct transition and good crystallinity. The transmission of films is increased up to 80% with increasing substrate temperature in wavelength ranged from 450nm to 1000nm. Also, a broad absorption band is observed in the range 1500–2000nm. This band could be attributed to the increase in free carrier concentration which confirmed by a reasonable decrease in the film sheet resistance. The band gap Eg is determined and found to be in the range 2.45–2.55eV. The sheet resistance is reduced with increasing deposition temperature due to the increase in free carrier concentration and found to be 66Ω/□ at 450°C

Reliable Machine Learning Model for IIoT Botnet Detection

Due to the growing number of Internet of Things (IoT) devices, network attacks like denial of service (DoS) and floods are rising for security and reliability issues. As a result of these attacks, IoT devices suffer from denial of service and network disruption. Researchers have implemented different techniques to identify attacks aimed at vulnerable Internet of Things (IoT) devices. In this study, we propose a novel features selection algorithm FGOA-kNN based on a hybrid filter and wrapper selection approaches to select the most relevant features. The novel approach integrated with clustering rank the features and then applies the Grasshopper algorithm (GOA) to minimize the top-ranked features. Moreover, a proposed algorithm, IHHO, selects and adapts the neural network’s hyper parameters to detect botnets efficiently. The proposed Harris Hawks algorithm is enhanced with three improvements to improve the global search process for optimal solutions. To tackle the problem of population diversity, a chaotic map function is utilized for initialization. The escape energy of hawks is updated with a new nonlinear formula to avoid the local minima and better balance between exploration and exploitation. Furthermore, the exploitation phase of HHO is enhanced using a new elite operator ROBL. The proposed model combines unsupervised, clustering, and supervised approaches to detect intrusion behaviors. The N-BaIoT dataset is utilized to validate the proposed model. Many recent techniques were used to assess and compare the proposed model’s performance. The result demonstrates that the proposed model is better than other variations at detecting multiclass botnet attacks

Evaluation of Clinical and Biochemical Traits in Egyptian Barki Sheep with Different Growth Performances.

The Barki sheep industry is becoming increasingly important in Egypt because of the high quality of their meat and wool. This sheep breed is also commonly known for its resistance to arid and harsh environmental conditions. Such characteristics can be exploited in solving the problematic situation of inadequate animal protein for human consumption, particularly under climatic changes. However, very few studies have investigated aspects of breeding, nutrition, and susceptibility to infectious or non-infectious diseases in Barki sheep. Herein, we propose to unravel the differences in the clinical and biochemical profiles among Barki sheep of different growth rates. We measured clinical and biochemical parameters in stunted (n = 10; test group) and in good body condition (n = 9; control group) Barki sheep. Animals subjected to this experiment were of the same sex (female), age (12 months old), and housed in the same farm with similar conditions of feeding, management practice, and vaccination and deworming regimens. Regarding clinical examination, stunted/tested sheep showed a significantly higher pulse and respiratory rate compared to sheep with a good body condition/control group. The appetite, body temperature, and digestion processes were the same in both groups. In biochemical investigations, nutritional biomarkers were reduced markedly in stunted sheep compared with the control sheep, including total protein (p = 0.0445), albumin (p = 0.0087), cholesterol (p = 0.0007), and triglycerides (p = 0.0059). In addition, the Barki sheep test group suffered from higher levels of urea and blood urea nitrogen than the control group. Consistently, growth and thyroid hormone levels were lower in stunted sheep than the control sheep, although the differences were not statistically significant (p > 0.05). No significant differences were detected in both groups for serum levels of calcium, phosphorus, magnesium, iron, and zinc (p > 0.05). To detect the reasons for emaciation, certain debilitating infections were tested. All tested sheep showed negative coprological tests for gastrointestinal parasites, and had no obvious seropositivity to brucellosis, toxoplasmosis, neosporosis, or Q fever. This study demonstrates the useful biochemical markers for monitoring growth performance in Egyptian Barki sheep and unravels the usefulness of this breed in nationwide breeding and farming

Nurses’ perceptions of and satisfaction with the use of automated dispensing cabinets at the Heart and Cancer Centers in Qatar: a cross-sectional study

Background Automated dispensing cabinets (ADCs) were introduced in 2010 and 2012 at the Heart Hospital (HH) and National Center for Cancer Care and Research (NCCCR), both run by Hamad Medical Corporation in Qatar. These medication distribution systems provide computer-controlled storage, dispensing, and tracking of drugs at the point of care in patient care units. The purpose of this study was to assess nurses’ perceptions of and satisfaction with the use of ADCs at HH and NCCCR. Methods A cross-sectional study was conducted in the two institutions in May and November 2012 using a piloted, validated, online, and anonymous questionnaire. The questionnaire consisted of four parts: nurses’ sociodemographic and practice characteristics, 21 questions about their perceptions, one question about their overall satisfaction, and one about the system’s ease of use. The self-administered survey was distributed to 503 nurses working at HH and NCCCR over three weeks using Survey Monkey®. Results The survey response rate was 80 % (n = 403). No significant difference was found in perception scores between the two institutions (p = 0.06). Ninety-four percent (n = 378) of nurses agreed that the medication delivery system allowed them to do their job more safely, and 90 % (n = 363) nurses agreed that they now spent less time waiting for medication from the pharmacy than they did before the ADC system was introduced. Eighty seven percent (n = 349) nurses agreed that they were able to administer medication more efficiently with the ADC system. The overall satisfaction rate (either “very satisfied” or “satisfied”) for the two hospitals was 91 %. Conclusions The nurses’ perceptions of and levels of satisfaction with the ADC system were very good over the 6 months after complete implementation and integration at HH and NCCCR. ADCs appear to increase efficiency in the medication process and should therefore improve the quality of care