A piezoelectric cantilever beam with a tip mass at its free end is a common energy harvester configuration. This article introduces a new principle of designing such a harvester that increases the generated power without changing the resonance frequency of the harvester: the attraction force between two permanent magnets is used to add stiffness to the system. This magnetic stiffening counters the effect of the tip mass on the efficient operation frequency. Five set-ups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle: theoretical and experimental results show that magnetically stiffened harve

In this work, we study several features of the non-zero divisor graphs (ℵZD- graph) for the ring Zn of integer modulo n. For instance, the clique number, radius, girth, domination number, and the local clustering coefficient are determined. Furthermore, we present an algorithm that calculates the clique number and draws the non-zero divisor for the ring Zn.

The research aims to evaluate Islamic electronic libraries and their service for downloading research and illustrated books, explaining their origins, features and types. The research was limited to the libraries available on the Internet that provide the service for downloading research and illustrated books. The researcher relied on the survey approach to identify the libraries and a sample of them (20 libraries) was selected. For the purpose of evaluating it according to five criteria related to the preparation and publication of Islamic electronic libraries (the responsible party, the goals and objectives, the year, the services it provides, the sections and subject specializations of its contents) and five criteria related to the servi

Since the beginning of mankind, the view of the sky was present through observations with the naked eye, then it developed with time, and the sciences and tools of astronomical observations developed, including photometric measurements, which reached a high degree of accuracy in describing various cosmic phenomena, including the study of galaxies, their composition, and the differences between them, and from here the importance of this study emerged, to determine the differences between two distinct types of classification of galaxies, which are normal and barred spiral galaxies, where two galaxies NGC 4662 and NGC 2649 were chosen that represented certain types of galaxies to study the morphological structure of the two galaxies, a

Complex-valued regular functions that are normalized in the open unit disk are vastly studied. The current study introduces a new fractional integrodifferential (non-linear) operator. Based on the pre-Schwarzian derivative, certain appropriate stipulations on the parameters included in this con-structed operator to be univalent and bounded are investigated and determined.

Foreign direct investment is considered one of important bases to blind economy for many. Countries as if the main stage for developing national economy ,so for this ,many of countries give great prominence to the role of drivel foreign investment due to its importance as one of economic growth pillars in the developing countries. They offer a support for modern technology, organizational and managerial skills.        

  Dneto the importance of direct foreign investment on the economic growth, today, we discover that Iraq in need to rebnlid the in frastructuve and renew what has been destroyed during was in many production and export institutions . as wel

   الضاد والظاء موطن تفرد العربية وفخرها ، الفت فيهما العشرات والعشرات من المصنفات الثرّة لكثرة ذرائع تلابسهما والخلط بينهما ، فهما متشابهان في هيكل البناء ، وإخراجهما متداخل على اللسان ، وألفاظهما متناظرة برحابة في الإملاء ، فضلاعن  اشكالهما  إلى حدّ الآن ، مما حثني على التفكير في وسائل تسهل المطروح وتمد جسراً بين أجزائه عسى أن تدنو قطافه في دفع الشبهة ومواراتها ، فتحصلت لي امور ادرتها بكلمتين مف

Abstract :

The Aims of this research is to describe the concept of risk, its type and method of measurement, and to clarify the impact of these risks on the expected cash flow statement and the preparation of the target cash flow statement that takes these risks into consideration. Because the local economic environment is exposed to many risks, Therefore, this list will be predictive, which will help the economic unit to make administrative decisions, especially decisions related to operational, investment and financing activities. Therefore, the research problem is based on the fact that most of the local economic units are the list of flows According to the actual basis and not according to the discretionary basis (bud

Emotional exhaustion considered one of the critical factors in the formation and composition of organizational behavior of individuals within organizations, as well as social behavior and psychological, and emotional exhaustion is one of the three components of burnout, as well as depersonalization (cynicism) and low achievement, the emergence of research relevant to this concept began at the beginning of the seventies of the twentieth century, then started to become clear features in the eighties it. This research aims to build intellectual framework for draining emotional exhaustion through highlight on most important philosophical contents, as well as review and analysis of some models associated with this concept, and then a