The aim of this study is to shed light on the importance of biofuels as an alternative to conventional energy, in addition to the importance of preserving agricultural crops, which are the main source of this fuel, to maintain food security, especially in developing countries. The increase in global oil prices, in addition to the fear of global warming, are among the main factors that draw the world’s attention to searching for alternative sources of traditional energy, which are sustainable on the one hand, and on the other hand reduce carbon emissions. Therefore, the volume of global investment in renewable energy in general, and in liquid biofuels and biomass in particular, has increased. Global fears emerged that the excessive conversion of large farms suitable for growing food to energy production would threaten global food security. In the first ten years of the new millennium, biofuel production increased fivefold, and the largest increase in biofuel production was recorded in 2007-2008, coinciding with a sharp rise in food prices. Compared to the average food prices in the period 2002-2004, the average global prices of cereals, oils and fats traded were 2 to 2.5 times higher in 2008, this continuous increase in the use of food crops to produce biofuels has reflected on global food security. Accordingly, this review article will address previous studies on biofuel production; identify the theoretical framework for the concept of biofuels and its characteristics, and the relationship between biofuels and food security. In this study, we presented biofuels, which are considered one of the important categories in the field of renewable energy and its environmental and economic effects, as well as the experiences of some countries in its production, and the possibility of benefiting from the natural resources available for its production. We will discuss the scientific (chemical) principles of biofuel production.
In this study, pebble bed as an absorber and storage material was placed in a south facing, flat plate air-type solar collector at fixed tilt angle of (45°). The effect of this material and differ- ent parameters on collector efficiency has been investigated experimentally and
theoretically. Two operation modes were employed to study the performance of the solar air heater. An inte- grated mode of continuous operation of the system during the period of (11:00 am – 3:00 pm) and non-integrated mode in which the system stored the solar energy through the day then used the stored energy during the period of (3:00 pm – 8:00 pm). The results of parametric study in case of continuous operating showed that the maximum average temperatur
The field of Optical Character Recognition (OCR) is the process of converting an image of text into a machine-readable text format. The classification of Arabic manuscripts in general is part of this field. In recent years, the processing of Arabian image databases by deep learning architectures has experienced a remarkable development. However, this remains insufficient to satisfy the enormous wealth of Arabic manuscripts. In this research, a deep learning architecture is used to address the issue of classifying Arabic letters written by hand. The method based on a convolutional neural network (CNN) architecture as a self-extractor and classifier. Considering the nature of the dataset images (binary images), the contours of the alphabet
... Show MoreBackground: Knowledge about the prevalence and distribution of pathologies in a particular location is important when a differential diagnosis is being formulated. The aim of this study was to describe the prevalence and the clinicopathological features of odontogenic cysts and tumors affecting the maxilla and to discuss the unusual presentation of those lesions within maxillary sinus.
Materials and Methods: A multicenter retrospective analysis was performed on pathology archives of patients who were diagnosed with maxillary odontogenic cysts and tumors from 2010 to 2020. Data were collected with respect to age, gender and location.
Result: A total of 384 cases was identified, 320 (83.3%) cases were diagnosed as odontogenic
... Show MoreGod saw his servants with truth and light, and made him easy for them, and he commanded those who help them, including a counselor, guide and preacher, so if a Muslim sees deficiencies or defects, he must help him to reform and refine it. That it was in the hands of the prophets, God Almighty created the human being together straight, then melted on those scholars and researchers in all religions on psychological counseling and religious sychotherapy, stressing the importance of religious values in the process of understanding man in the process of psychotherapy and in controlling human behavior. A lot of research and studies have been published. I dealt with the religious approach in the process of treating mental disorders and the aim of
... Show MoreIt is proposed and studied a prey-predator system with a Holling type II functional response that merges predation fear with a predator-dependent prey's refuge. Understanding the impact of fear and refuge on the system's dynamic behavior is one of the objectives. All conceivable steady-states are investigated for their stability. The persistence condition of the system has been established. Local bifurcation analysis is performed in the Sotomayor sense. Extensive numerical simulation with varied parameters was used to explore the system's global dynamics. A limit cycle and a point attractor are the two types of attractors in the system. It's also interesting to note that the system exhibits bi-stability between these 2 types of attractors.
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