<p>Photovoltaic (PV) systems are becoming increasingly popular; however, arc faults on the direct current (DC) side are becoming more widespread as a result of the effects of aging as well as the trend toward higher DC voltage levels, posing severe risk to human safety and system stability. The parallel arc faults present higher level of current as compared with the series arc faults, making it more difficult to spot the series arc. In this paper and for the aim of condition monitoring, the features of a DC series arc fault are analyzed by analysing the arc features, performing model’s simulation in PSCAD, and carrying out experimental studies. Various arc models are simulated and investigated; for low current arcs, the heuristic model is used where a set of parameters established. Moreover, the heuristic model’s simulated arc has been shown to be compatible with the experimental data. The features of arc noise in the electrode separation region and steady-arcing states with varied gap widths are investigated. It has been discovered that after an arc fault occurs, arc noise increases, notably in the frequency range below 50 kHz; where this property is useful for detecting DC series arc faults. Besides that, variations in air gap width are more sensitive to frequencies under 5 kHz.</p>
In this paper, there are two main objectives. The first objective is to study the relationship between the density property and some modules in detail, for instance; semisimple and divisible modules. The Addition complement has a good relationship with the density property of the modules as this importance is highlighted by any submodule N of M has an addition complement with Rad(M)=0. The second objective is to clarify the relationship between the density property and the essential submodules with some examples. As an example of this relationship, we studied the torsion-free module and its relationship with the essential submodules in module M.
In this work, we focused on studying 1,4-naphthoquinones and their derivatives, and knowing the methods of preparing them using different auxiliary agents and forming derivatives containing heterocyclic rings, active groups and saturated rings containing heterogeneous elements . In addition, due to their strong antibacterial, antifungal and anticancer activity, 1,4-naphthoquinone compounds biological importance and are considered a source of various pharmaceutical compounds.
Four different spectrophotometric methods are used in this study for the determination of Sulfamethoxazole and sulfanilamide drugs in pharmaceutical compounds, synthetic samples, and in their pure forms. The work comprises four chapters which are shown in the following: Chapter One: Includes a brief for Ultraviolet-Visible (UV-VIS) Absorption spectroscopy, antibacterial drugs and sulfonamides with some methods for their determination. The chapter lists two methods for optimization; univariate method and multivariate method. The later includes different types, two of these were mentioned; simplex method and design of experiment method. Chapter Two: Includes reaction of the two studied drugs with sodium nitrite and hydrochloric acid for diazo
... Show MoreThis piece of research deals with assimilation as one of the phonological processes in the language. It is a trial to give more attention to this important process in English language with deep explanation to its counterpart in Arabic. in addition, this study sheds light on the points of similarities and differences concerning this process in the two languages. Assimilation in English means two sounds are involved, and one becomes more like the other.
The assimilating phoneme picks up one or more of the features of another nearby phoneme. The English phoneme /n/ has t
... Show MoreMedia has become a common platform for communication as a tool of offense. English language has many insult words which are commonly used in the world of media. This study investigates the socio-pragmatic aspect of insulting in English news. It aims at identifying and analysing insult words and expressions used by news presenters. To specify the problem of the study, language has a harmful power that hurts the addressees and seriously harm their psychological well-being. The insulting words that are an element of all human languages are the source of this abusive power. The study questions sought to find out are if news presenters use insult words, which insult words, and in what social contexts. In this study, the descriptive method is use
... Show MoreA theoretical and experimental investigation was carried out to study the behavior of a two-phase closed thermosyphon loop (TPCTL) during steady-state operation using different working fluids. Three working fluids were investigated, i.e., distilled water, methanol, and ethanol. The TPCTL was constructed from an evaporator, condenser, and two pipelines (riser and downcomer). The driving force is the difference in pressure between the evaporator and condenser sections and the fluid returns to the heating section by gravity. In this study, the significant parameters used in the experiments were filling ratios (FR%) of 50%, 75%, and 100% and heat-input range at the evaporator section of 215-860.2 W. When the loop reached to
... Show Moreيمثل الأخذ بالنظام الفيدرالي أطاراً تنظيمياً لشكل الدولة و مرحلة تحول مهمة في بنية الدولة العامة في مختلف مجالاتها، فالانتقال من المركزية في أدارة الشؤون العامة للدولة الى النمط الفيدرالي يمثل تحولا بنيوياً وسيكولوجياً ،حيث يكون هنالك توزيع مكاني - عمودي للسلطة والثروة بين الوحدات المكونة للدولة بشكل يختلف كليا عن الحالة المركزية، ونجد صور تنظيمية عديدة تتأسس ضمن اطار الفيدرالية العام ،
... Show MoreTrimethoprim derivative Schiff bases are versatile ligands synthesized with carbonyl groups from the condensation of primary amines (amino acids). Because of their broad range of biological activity, these compounds are very important in the medical and pharmaceutical fields. Biological activities such as antibacterial, antifungal and antitumor activity are often seen. Transition metal complexes derived from biological activity Schiff base ligands have been commonly used.
In the name of God, praise be to God, and prayers and peace be upon the best of God’s creation, Muhammad bin Abdullah, and upon his family and companions, and from his family:
And after:
He saw from verbs that transcend one effect if it is visual and to two effects if it is heart and this action has several strokes and it is an awareness of the sense and illusion and imagination and reason and in addition to that it has many meanings dealt with in the glossary books and as for what the verb included in the audio studies it is the explanation and deletion and slurring The heart of my place. As for what the grammatical studies included, it focuses on one or two effects according to its l
The efforts in designing and developing lightweight cryptography (LWC) started a decade ago. Many scholarly studies in literature report the enhancement of conventional cryptographic algorithms and the development of new algorithms. This significant number of studies resulted in the rise of many review studies on LWC in IoT. Due to the vast number of review studies on LWC in IoT, it is not known what the studies cover and how extensive the review studies are. Therefore, this article aimed to bridge the gap in the review studies by conducting a systematic scoping study. It analyzed the existing review articles on LWC in IoT to discover the extensiveness of the reviews and the topics covered. The results of the study suggested that many re
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