Solar energy is the most abundant renewable energy source. This energy can be converted directly into electricity using solar panels. The fixed tilt solar panels are the most practical and the most widely installed throughout the world. Optimum tilt angle calculation has the advantage that it does not use expensive solar trackers. This research calculates the seasonal optimum tilt angle of solar panels for 17 cities in Iraq and 83 cities in 83 countries distributed around the world. Solar Panel Angle Calculator program was used in calculating the optimum tilt angles from vertical. The optimum tilt angle varies between 6° and 112° throughout the year. This angle for winter, spring/ autumn and summer seasons are found to be between 6° to 66°, 30° to 89° and 54° to 112°, respectively. All angles calculated from the calculator program are validated by comparing it with those obtained from equations. An excellent agreement was established. Cities which have approximately the same absolute values of the latitudes are have the same optimum tilt angles. Based on the results, adjusting angles four times a year is recommended. This work can serve as a guidance for installing solar panels.
Samples of marsh frog included 148 sexually mature males were collected in Baghdad
from December 1992 to December 1993 to December 1993. The testis weight was expressed
as percentage of the body weight. The percent mean weights of testis were at their minimal
weight (0.255%) during April (spawning period).
Testis weight has increased until reached its greatest average weight in August (0.785%).
During the winter there is a slight decrease in weight with a more obvious fall at the spawning
months. From the results obtained from the present work on Rana ridibunda and from the
observations on annual cycle in testis weight of some temperate zone anurans we notice that
testes tend to be lowest after spawning and the te
The present study deals with successive stages of productive
operations happened to produce a production within each stage befo re it moves to the next one. ll cou ld be deduced that this study is an extension to what bas been mentioned in (1 ) .ln (I), the optimum distribution of di!Terent jobs of workers and machines in the productive operations has been st ud ied whi le the study invol ves the optimum schedule for the succession of these operations presuming that thay have already been distributed on machines and workers (2).A mathematical form has been put for this study to define the "Object.ive Function "
... Show MoreCities have witnessed great changes since the planning of the first cities. This is due to the increase in population and problems in services which affect urban security. As such, urban security is directed and affected by the nature of city planning and the types of services. Besides, the kind of services plays an imminent place in providing urban security at all levels. Other factors that influence urban security can be limited to the increase of population, economic and social changes. This leads to losing urban control. This study will explore the historical chronology to identify weaknesses in urban planning since its dawn and reaching solutions to protect urban security. The importance of the research lies in achieving urban secur
... Show MoreCities have witnessed great changes since the planning of the first cities. This is due to the increase in population and problems in services that affect urban security. As such, urban security is directed and affected by the nature of city planning and the types of services. Besides, the kind of services plays an imminent place in providing urban security at all levels. Other factors that influence urban security can be limited to the increase of population, economic and social changes. This leads to losing urban control. This study will explore the historical chronology to identify weaknesses in urban planning since its dawn and reaching solutions to protect urban security. The importance of the research lies in achieving urban securi
... Show MoreThe aerodynamic characteristics of the forward swept wing aircraft have been studied theoretically and an experimentally investigation for the wake field generated by this configuration have been carried out. Low order panel method with the Dirichlet boundary condition have been used to solve the case of the steady, inviscid and compressible flow. Two different panel method techniques have been employed: the source-doublet and the doublet method. The thickness for the various components was considered in the study. Prandtl-Glauert similarity rule has been used to account for the compressibility effects. Experimentally, a model was manufactured from wood with body length (290mm) and main wing span was (204mm). The primary objective of th
... Show MoreA summary of zooplankton research done in Peruvian marine waters is presented. We first provide a brief overview of the evolution of zooplankton studies off Peru before reviewing zooplankton biodiversity, regional distribution, seasonal and interannual fluctuation, trophodynamics, secondary production, and modeling are some of these topics. We evaluate research on various meroplankton, macroplankton, mesoplankton, and microplankton groups and provide a list of species from both published and unpublished sources. Three regional zooplankton groups have been identified: A shelf group on the continental shelf dominated by Acartia tonsa and Centropages brachiatus; A slope group on the continental shelf with siphonophores, bivalves, foramin
... Show MoreThe subject of fear is one of the most important tasks that one should seek to find out the reasons behind it, and push it up with all its sound mental concepts.
The main reason for the lack of security and fear and disturbance in the world is to commit the legitimate violations that God warned us in his Holy Book as well as in the Sunnah of His Prophet (peace be upon him).
The talk about the causes of fear in the Koran is not limited to the word (fear) Fakk but came in different and varied methods such as (horror) and (awe) and (shares) and (narrow).
The main objective of this paper is to determine an acceptable value of eccentricity for the satellites in a Low Earth Orbit LEO that are affected by drag perturbation only. The method of converting the orbital elements into state vectors was presented. Perturbed equation of motion was numerically integrated using 4th order Runge-Kutta’s method and the perturbation in orbital elements for different altitudes and eccentricities were tested and analysed during 84.23 days. The results indicated to the value of semi major axis and eccentricity at altitude 200 km and eccentricity 0.001are more stable. As well, at altitude 600 km and eccentricity 0.01, but at 800 km a
Motives: The research deals with the issue of urban sprawl on agricultural lands. It is an urban problem caused by rapid urbanization and poor planning. It is considered one problem that threatens cities with environmental and health disasters. It also threatens agricultural life and the green belt surrounding cities. Changes in urban sprawl on agricultural land are associated with complex processes that lead to multiple social, economic, political, and environmental risks and thus pose a threat and an obstacle to the sustainability of cities. Aim: The research aims to study and evaluate the reality of the city of Baghdad and the extent of its ability and flexibility to withstand the disaster of urban sprawl on agricultural lands. T
... Show More