An essential tool for studying the web is its ability to show how energy moves through an ecosystem. Understanding and elucidating the relationship between species variety and their placement within the inclusive trophic dynamics is also beneficial. A food web ecological model with prey and two rival predators under fear and wind flow conditions is developed in this article. The boundedness and positivity of the system’s solution are established mathematically. The stability and existence constraints of the system’s equilibria are examined. The proposed system’s persistence limitations are established. Additionally, the bifurcation analysis of every potential equilibrium is examined using the Sotomayor theorem. To describe the

Production of fatty acid esters (biodiesel) from oleic acid and 2-ethylhexanol using sulfated zirconia as solid catalyst for the production of biodiesel was investigated in this work.

       The parameters studied were temperature of reaction (100 to 130°C), molar ratio of alcohol to free fatty acid (1:1 to 3:1), concentration of catalyst (0.5 to 3%wt), mixing speed (500 to 900 rpm) and types of sulfated zirconia (i.e modified, commercial, prepared  catalyst according to literature and reused catalyst). The results show the best conversion to biodiesel was 97.74% at conditions of 130°C, 3:1, 2wt% and 650 rpm using modified catalyst respectively. Also, modified c

   The time spent in drilling ahead is usually a significant portion of total well cost. Drilling is an expensive operation including the cost of equipment and material used during the penetration of rock plus crew efforts in order to finish the well without serious problems. Knowing the rate of penetration should help in speculation of the cost and lead to optimize drilling outgoings. Ten wells in the Nasiriya oil field have been selected based on the availability of the data. Dynamic elastic properties of Mishrif formation in the selected wells were determined by using Interactive Petrophysics (IP V3.5) software based on the las files and log record provided. The average rate of penetration and average dynamic elastic propert

Direct contact membrane distillation is an effective method for production of fresh water from saline water. In this study two samples were used as feed solutions; the first one was RO waste from Al-Hilla Coca-Cola Factory (TDS= 2382 mg/l) and the other was Haji Ali drainage water (TDS= 4127 mg/l). Polytetrafluoroethylene (PTFE) hydrophobic membrane supported with polypropylene (PP) was used as flat sheet form with plate and frame cell. Results proved that membrane distillation is an effective technique to produce fresh water with high quality from brine with low salinity content. With membrane area of 8x8 cm², the volume of treated water decreased from 34.97 ml at first half hour to 33.02 ml after 180 min of

In a world of limited space, the owners are always surrounded by others next to them, and, consequently, there is hardly any activity which the owner may exercise on his land which would not affect the other owners. If he builds a building, that building may block the sun's rays or the air from the buildings next to it and owned by other people. And if he runs a business, the lands adjacent to that business may be overburdened with the accompanying noise or traffic. If oil is prospected in a land, the neighboring lands may be deprived of oil or their owners may be exposed to toxic fumes. Hence the importance of researching the intention of harming others, as it is one of the most important forms of abuse in the use of the right (especially

The issue of the research lies in the non-representation of the models developed for the communication process in the interaction and networking processes through social media, as the research sought to build a network model of communication according to the specific data and features of social media platforms in order to reach a special generalization to understand how the process of networking operates in cyberspace.

The researcher followed the analytical survey approach as she described the communication models outwardly in order to be able to build a networked communication model that represents the flow of post-reactive communication. Therefore, it has been named "Nebula - Sadeem" after the concept of post-space and cosmic g

Diversity the terms and practice the organizational filed with different concepts and environment, which Iraqi environment part from them. Some organizational in Iraqi environment leave its basic oriented to agreement with the leader desire, their fore this research focus tow basic variable (organizational citizenship behavior & transparence), we supposition which is dependent to explanation the response variable (strategic leadership). The results justification in part and not justification in another part. For example the organizational citizenship behavior effect on some parte of the strategic leadership. The transparence have faraway to fly from the relation with organizational citizenship behavior and strategic leadershi

This work presents a computer studying to simulate the charging process of a dust grain immersed in plasma with negative ions. The study based on the discrete charging model. The model was developed to take into account the effect of negative ions on charging process of dust grain.
The model was translated to a numerical calculation by using computer programs. The program of model has been written with FORTRAN programming language to calculate the charging process for a dust particle in plasma with negative ion, the time distribution of a dust charge, number charge equilibrium and charging time for different value of ηe (ratio of number density of electron to number density of positive ion).