Severe asthma in children—a review of definitions, epidemiology, and treatment options in 2019

Peer reviewedPostprin

Design of spill tube with features for controlling air bubble generated for aircraft applicaitons

In this spill tube research paper, an analytical model is to be created of the distribution of pressure of the air trapped in the spill tube system, where fuel transfer from the sealed tank to the adjacent tanks occurs. This research is a part of a large fuel tank research project. A series of experiments were performed in order to characterize the flow of fluid in the entire spill tube with tubes of different diameters. The experiments were based on a test matrix, and results were kept in increasing order so as to obtain a simple conclusion. Also, trends can be drawn in the form of analytical models that were based on the equations obtained from fluid mechanics books. The experiments performed per spill tube were of two types: first, 0% downstream quantity was taken, and second, 50% downstream quantity was taken. An analytical model was developed using Simulink on the completion of the test matrix. The equations implemented in Simulink were compared with the experimental data so as to ensure the accuracy of the presentation. For various bell mouth geometries, the pressure was optimized with respect to the input flow of mass

Evaluation of the Electronic Services System for Taibah University in Light of the Dimensions of Information Systems

The study aims to identify the strengths and weaknesses of the electronic services system at Taibah University by highlighting the achievements of aspects of the information systems from faculty members’ perspectives. First, we defined the three dimensions of information systems using a descriptive approach; then, with the help of four experts, we designed a questionnaire and distributed it to 150 faculty members from different Taibah University departments. We applied statistical analyses, including exploratory factor analysis and frequency analysis, we also applied confirmatory factor analysis and structural equation modeling. The study concludes with a proposed scenario for improving the performance of the electronic services system at Taibah University. Keywords: electronic services system (ES), information systems dimensions, confirmatory factor analysis (CFA).

Factors affecting quality during the construction phase in Iraqi government companies

Construction projects play a significant part in the development of any country and quality is one of the important factors in the success of the construction industry. There is a lack of understanding of quality is the problem in the construction industry in Iraq, but the main problem is the absence of good quality supervision of the construction industry. Based on the literature review yielded managers, designers, and contractors with necessary information needed to better manage the quality of a construction project by identifying the factors that affect process quality of construction projects and to rank them by degree of importance and develop a model to represent the factors affecting the overall quality of Construction projects. This study was based on questionnaire surveys, which was designed based on literature review. After, validation a total 109 questionnaires were collected among project manager, quality engineer, and general manager in Baghdad, the capital city of Iraq. Data were analysed using descriptive statistics and multiple regression analysis applying SPSS software Ver.21. The results of data analysis indicated that the level of importance all factors were more than a moderate level and the highest level which was almost high belonged to the material. The other factors, including Quality systems, Owner, Design, Equipment, Labors and contractor almost ranged between 3.69-3.75. Based on multiple regression analysis among all factors only “contractor” did not show any significant effect on quality in construction projects. The highest effect belonged to, quality systems with (β=0.289, P value<0.001) and then owner and materials followed by design, equipment, site staff and the lowest impact was observed for labor factor (β=0.137, P value=0.049)

The Impact of Geopolitical Risk on Sustainable Markets: A Quantile-Time-Frequency Analysis

We examine the impact of Geopolitical Risk (GPR) on green, clean, and socially responsible markets by employing the newly proposed Wavelet Quantile Correlation, Cross-quantilogram and Causality-in-quantiles. Unlike earlier studies, we incorporate the GPR index to encompass the risk linked to conflict, acts of terrorism, and political tensions. In brief, our findings show that GPR emerges as a significant factor influencing market behavior, with distinct patterns observed across different time scales and trading horizons. Our results are beneficial for investors and portfolio managers to adopt more rational investment strategies and for policymakers to make appropriate policy arrangements. 1 1 Corresponding author: Ahmed H. Elsayed ([email protected]

Quality of service acceptance model for cloud service in Palestinian higher education institutions

Cloud computing service has been found to be effective in increasing the capacity of Higher Education Institutions (HEIs) since it delivers services through enhanced information technology capabilities. Quality of Service (QoS) in cloud service is considered a rapidly growing phenomenon to guarantee a high level of service and is identified as an essential aspect of service provision. Despite the importance of QoS, identifying the QoS acceptance factors by decision-makers for cloud based services in HEIs in Palestine has been a critical challenge. There are limited studies conducted on QoS acceptance factors from Technological, Organizational, Environmental and Human aspects, hence, this study addressed this gap and investigated potential factors influencing QoS acceptance by decision makers in the context of HEIs in Palestine. This study proposed a research model by combining Technological Organizational Environmental (TOE) framework and Human Organizational Technology (HOT) fit framework. The research model was developed through the factors identified through a comprehensive literature review. Seventeen hypotheses were developed and the significance of the relationship between the factors were investigated using a quantitative approach. A survey method using a paper-based questionnaire was employed to collect data from 267 decision makers in the target higher education institutions. The data were analysed using Structural Equation Modelling (SEM) with Partial Least Squares (PLS) technique. The finding used to develop the QoS acceptance model facilitated the understanding of factors impacting QoS acceptance by the HEIs in Palestine. The results that indicated the most significant factors for QoS acceptance by HEIs in Palestine were Availability (P= 0.046, p-value = 0.002), Compatibility (P= 0.043, p-value= 0.001), Security Concern (P= 0.037, p-value= 0.006), and Relative Advantage (P= 0.046, p-value= 0.001), Vendor Support (P= 0.037, p-value= 0.025), Legal Issues (P= 0.068, p-value= 0.027) and Competitive Pressure (P= 0.064, p-value= 0.028). The results of this study and the proposed model would assist the practitioners in HEIs to better understand the importance of QoS acceptance in cloud service

Catalytic Dehydration and Etherification of Alcohol and Glycerol to Produce Biodiesel Compatible Fuel Additives

Global glycerol supplies have been increasing steadily due to the continual expansion of biodiesel production. This glut has resulted in lower demand for glycerol, price deflation and even environmental concerns. Crude glycerol produced from biodiesel transesterification is not of high quality due to catalyst and alcohol contamination and transportation and disposal issues—all of which have added further constraints to this industry. In light of this, a product that could utilize glycerol, excess alcohol and the catalyst could enhance the value proposition for the biodiesel industry. Here, we show that glycerol can be reacted with methanol and tert-butanol in the presence of common transesterification catalysts to produce an ether-rich mixture that is miscible with biodiesel. Initially, the bimolecular dehydration of two alcohols, n-propanol and methanol, with catalysts that are used in transesterification was investigated. Experiments were carried out to evaluate the feasibility of promoting the etherification reaction using methanol and n-propanol as model alcohols. When methanol and npropanol are reacted together, three types of ethers can be produced: dimethyl ether, methyl-propyl ether (also referred to as methoxypropane), and di-propyl ether. The latter two ethers are of more fuel interest due to their ability to stay in the liquid phase at room temperature; however, the ability of catalysts to selectively produce liquid ethers is not established. Initial studies were conducted to discern the effect of sulfuric acid, amberlyst-36 and titanium isopropoxide—catalysts that are known to be effective for transesterification— on the substrate conversion, ether yield, and selectivity using n-propanol at four levels of temperature. Subsequent studies with n-propanol and methanol looked at the impact of select catalyst concentrations and reaction conditions. Studies indicate that liquid mixtures of 1-methoxypropane and di-propyl ethers could be formed by reacting npropanol and methanol in the presence of sulfuric acid or Amberlyst 36. Higher concentrations of sulfuric acid (5% w/w) coupled with higher temperatures (>140oC) favored substrate conversion and ether yields. However, it was revealed that the selectivity toward specific ethers (i.e. coupling of the two larger alcohols to produce dipropyl ether) could be controlled by appropriate selection of the catalyst. It is anticipated that the results would be a starting point for a simple technique to produce specific ethers using a mixture of alcohols. This technique could be applied for applications such as transesterification byproduct utilization. Subsequent studies where glycerol was used as one of the primary alcohols looked at the impact of type and concentration of catalysts, molar ratio of reactants, temperature, and reaction time on alcohol conversion, product yield, selectivity and select fuel properties. Results show that both NaOH and H2SO4 are active for producing etherified blends from glycerol that are miscible with biodiesel. These results could be a starting point for the development of an effective fuel additive to reuse the byproduct glycerol and excess alcohol resulting from biodiesel production

A comparative study of IP Versions 4, 5, and 6

This research examines the Internet Protocol (IP) versions 4, 5, and 6, as well as the differences between them and which protocol is more suitable for the future of the internet, among other things. Through this research, we have established the most advantageous characteristics of these protocols, as well as the specific elements that each protocol uses to allow the internet network to operate at maximum capacity. The main aim of this study is to discover which of the internet protocols, IPv4, IPv5, or IPv6, is the most widely used. IPv4 is the most widely used protocol, followed by IPv5. The most essential elements of getting a more relevant job on the internet network are highlighted in this article. It all comes down to how IP protocols operate and what they accomplish

Synthesis and characterization of some biological active transition metal complexes of Schiff base derived from cefixime with mixed ligand 8-hydroxy quinoline

The aim of the work is synthesis and characterization of bidentate ligand [dipotassium sodium7-((E)-2-(2-((Z)-1-carboxylatoethylideneamino)thiazol-4-yl)-2 (carboxylatemethoxyimino) acet amido)-8-oxo-3-vinyl-5- thia-1-azabicyclo[4.2.0] oct-2- ene-2- carboxylate] [Nak2L], from the reaction of cefixime with sodium pyruvet to produce the ligand [Nak2L], the reaction was carried out in methanol as a solvent under reflux. The prepared ligand [Nak2L] which was characterized by FT-IR, UV-Vis spectroscopy, 1H, 13C-NMR spectra, Mass spectra, (C.H.N) and melting point. The mixed ligand complexes were prepared from ligand [Nak2L] was used as a primary ligand while 8-hydroxy quinoline [Q] was used as a secondary ligand with metal ion M(?).Where M(?) = (Mn ,Co ,Ni ,Cu ,Zn and Cd) at reflux ,using methanol as a solvent, KOH as a base. Complexes of the composition [(M)2(Q)2(KL)(H2O)4] with (2:2:1) molar ratio were prepared. All the complexes were characterized by spectroscopic methods (FT-IR, UV-Vis spectroscopy) along with elemental analysis (A.A), chloride content and melting point measurements were carried out, together with conductivity and magnetic susceptibility. These measurements showed octahedral geometry around (Mn??, Co??, Ni??, Cu??, Zn?? and Cd??) ions. The biological activity of the ligands [NaK2L], [Q] and complexes [(M)2(Q)2(KL)(H2O)4] were studied by using inhibition method