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.
Background: Orthodontic tooth movement is characterized by tissue reactions, which consist of an inflammatoryresponse in periodontal ligament and followed by bone remodeling in the periodontium depending on the forces applied. These processes trigger the secretion of various proteins and enzymes into the saliva.The purpose of thi study was to evaluate the activity of alkaline phosphatase (ALP) in saliva during orthodontic tooth movement using different magnitude of continuous orthodontic forces.
Materials and Methods: Thirty orthodontic patients (12 males and 18 females) aged 17-23 years with class II division I malocclusion all requiring bilateral maxillary first premolar extractions were randomly divided into three groups according t
Zinc Oxide thin film of 2 μm thickness has been grown on glass substrate by pulsed laser deposition technique at substrate temperature of 500 oC under the vacuum pressure of 8×10-2 mbar. The optical properties concerning the absorption, and transmission spectra were studied for the prepared thin film. From the transmission spectra, the optical gap and linear refractive index of the ZnO thin film was determined. The structure of the ZnO thin film was tested with X-Ray diffraction and it was formed to be a polycrystalline with many peaks.
Calculating the Inverse Kinematic (IK) equations is a complex problem due to the nonlinearity of these equations. Choosing the end effector orientation affects the reach of the target location. The Forward Kinematics (FK) of Humanoid Robotic Legs (HRL) is determined by using DenavitHartenberg (DH) method. The HRL has two legs with five Degrees of Freedom (DoF) each. The paper proposes using a Particle Swarm Optimization (PSO) algorithm to optimize the best orientation angle of the end effector of HRL. The selected orientation angle is used to solve the IK equations to reach the target location with minimum error. The performance of the proposed method is measured by six scenarios with different simulated positions of the legs. The proposed
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Abstract.The goal of this article is to find the CEO of Iraqi companies that use strategic planning and determine if they are capable of diagnosing the traits of strategic planning systems that improve these companies' capacity to successfully address crisis-related needs. The capacity of the company to successfully react to crisis needs and demands is enhanced by the use of strategic planning, according to a review of data from 64 enterprises utilizing statistical analysis. Furthermore, top and division or unit managers must be involved and committed for strategic planning to be successful. It also has to be planned with an external orientation and get more than just lip service from top and unit or division level managers. In other words,
... Show MoreSKF Sami I. Jafar, Mohammad J. Kadhim, Engineering and Technology Journal, 2018 - Cited by 4
Background: Deterioration of maxillofacial silicone properties due to microbial colonization is a common problem and leads to the replacement of the prosthesis. Incorporation of the antimicrobial agent into the silicone could be a solution. The purpose of this study was to evaluate the effect of silver-zinc zeolite addition on some mechanical properties of a maxillofacial silicone (VST-50). Materials and methods: Total 120 specimens were fabricated and divided into 3 groups: 40 specimens for tear strength test, 40 specimens for tensile and percentage of elongation tests and 40 specimens for Shore A hardness and surface roughness. Each group was divided into 4 subgroups according to the amount of zeolite added (0% “control”, 0.5%, 1% and
... Show MoreThe electrical performance of bottom-gate/top source-drain contact for p-channel organic field-effect transistors (OFETs) using poly(3-hexylthiophene) (P3HT) as an active semiconductor layer with two different gate dielectric materials, Polyvinylpyrrolidone (PVP) and Hafnium oxide (HfO2), is investigated in this work. The output and transfer characteristics were studied for HfO2, PVP and HfO2/PVP as organic gate insulator layer. Both characteristics show a high drain current at the gate dielectric HfO2/PVP equal to -0.0031A and -0.0015A for output and transfer characteristics respectively, this can be attributed to the increasing of the dielectric capacitance. Transcondactance characteristics also studied for the three organic mater
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ZnIn2(Se1-xTex)4 (ZIST) chalcopyrite semiconductor thin films at various contents (x = 0.0, 0.2, and 0.4) are deposited on glass and p type silicon (111) substrate to produce heterojunction solar cell by using the thermal evaporation technique at RT where the thickness of 500 nm with a vacuum of 1×10-5 mbar and a deposited rates of 5.1 nm/s. This study focuses on how differing x content effect on the factors affecting the solar cell characteristics of ZIST thin film and n-ZIST/p-Si heterojunction. X-ray diffraction XRD investigation shows that this structure of ZIST film is polycrystalline and tetragonal, with (112) preferred orientation at 2θ ≈ 27.01. Moreover, atomic force microscopy AFM is studying the external morphology of
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Photonic Crystal Fiber Fabry–Perot Interferometers (FPI) based on Surface Plasmon Resonance (SPR) was investigated in this paper in order to detect changes in photonic crystal fiber sensitivity with increasing temperature. FPI is composed of a PCF (ESM-12) solid core spliced with a single-mode fiber (SMF) on one side and a 40nm thick gold Nano film on the other. In order to obtain the SPR curve, the end of PCF can be spliced with the side of SMF before covering the gold film on the PCF. SPR results are included in the suggested sensor, based on the conclusions of the investigations. Resolution (R) is 0.0871, Signal-to-Noise Ratio (SNR) is 0.1867, a figure of merit (FOM) is 0.0069, and sensitivity (S) is 1.1481 . This sensor proposed is s
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