The present study was conducted to investigate effect of prey type on the relationship between age of females of Macrocyclops albidus and reproductive performance, which included each of mean number of nauplii, age at first brood, and age at first clutch. Results revealed that the correlation coefficient between the age at first brood and clutch and age of females fed on Artemia was significant P <0.05, being 0.65 and 0.81 respectively, while the correlations were not significant P>0.05 in females fed on mosquito larvae (Culex quinquefasciatus) and Paramecium nauplii. It was also found that the correlation coefficients between mean number of the nauplii and longevity in M. albidus were significant P<0.05 whereas, the correlations were not significant P>0.05 in the females fed on mosquito larvae. In view of our results, the mosquito larvae could be considered the best prey for the females of the M. albidus compared with the two type of preys (Artemia and Paramecium) as the correlation was negative and significant P<0.01 between the mean number of nauplii and the age of the M. albidus female, which means that the increasing of the number of nauplii is associated with decreasing in female age, while the correlation was negative and not significant P>0.05 between number of nauplii and the age of females fed on mosquito larvae which indicate that the persistency of females represented by the mean number of nauplii/clutch is higher than the two mentioned preys types and that will increase its opportunity to success during the application of the biological control programs of mosquito.
The purpose of this paper is to identifying the level of analytical thinking and its relationship to the skills of response and simple response to the foil weapon for students of the College of Physical Education and Sports Sciences, University of Basra. Achieving the objectives of the research requires the use of a research method, and accordingly, the researchers used the descriptive method using the survey method .The two researchers identified the research community with the students of the third stage - College of Physical Education and Sports Sciences / University of Basra / for the academic year (2021-2022). Their number is (45) students and the two researchers chose the entire research community to represent th
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An experimental and computational study is conducted to analyze the thermal performance of heat sinks and to pick up more profound information in this imperative field in the electronic cooling. One important approach to improve the heat transfer on the air-side of the heat exchanger is to adjust the fin geometry. Experiments are conducted to explore the impact of the changing of diverse operational and geometrical parameters on the heat sink thermal
performance. The working fluid used is air. Operational parameters includes: air Reynolds number (from 23597 to 3848.9) and heat flux (from 3954 to 38357 W/m
2 ). Conformational parameters includes: change the direction of air flow and the area of conduct
The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed. Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness.
The theoretical results show an increase in load capacity by (8.3%) in the presence of solid graphite particles with concentration of (16%) by weight as compared with pure oil, with increasing shear stress. .
In general the performance of hydrostatic thrust bearings improve for load carrying capacity, volume flow rate,
... Show MoreThe purpose of this paper is to depict the effect of adding a hydraulic accumulator to a hydraulic system. The experimental work includes using measuring devices with interface to measure the pressure and the vibration of the system directly by computer so as to show the effect of accumulator graphically for real conditions, also the effects of hydraulic accumulator for different applications
have been tested. A simulation analysis of the hydraulic control system using MATLAB.R2010b to study was made to study the stability of the system depending on the transfer function, to estimate the effect of adding the accumulator on stability of the system. A physical simulation test was made for the hydraulic system using MATLAB to show the ef
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For over a century, the global consumption of asphalt binder in asphalt mixture production has been substantial. In the Heet region (west of Iraq), two distinct forms of natural asphalt (NA) deposits exist: rock asphalt and sulfur spring asphalt. This study focused on using NA sourced from sulfur springs. The aim was to investigate the potential of incorporating NA into local asphalt mixtures. To achieve this, NA was heated to 163°C for varying durations. After heat treatment, laboratory tests were conducted on NA. The findings suggest that by heating NA for 20 hours, it conforms to Iraqi specifications in terms of physical properties. Furthermore, compared to conventional petroleum asphalt, treated NA showed greater
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In this paper a prey-predator-scavenger food web model is proposed and studied. It is assumed that the model considered the effect of harvesting and all the species are infected by some toxicants released by some other species. The stability analysis of all possible equilibrium points is discussed. The persistence conditions of the system are established. The occurrence of local bifurcation around the equilibrium points is investigated. Numerical simulation is used and the obtained solution curves are drawn to illustrate the results of the model. Finally, the nonexistence of periodic dynamics is discussed analytically as well as numerically.
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Abstract: Despite the distinct features of the continuous wave (CW) Terahertz (THz) emitter using photomixing technique, it suffers from the relatively low radiation output power. Therefore, one of effective ways to improve the photomixer emitter performance was using nanodimensions electrodes inside the optical active region of the device. Due to the nanodimension sizes and good electrical conductivity of silver nanowires (Ag-NWs), they have been exploited as THz emitter electrodes. The excited surface plasmon polariton waves (SPPs) on the surface of nanowire enhances the incident excitation signal. Therefore, the photomixer based Ag-NW compared to conventional one significantly exhibits higher THz output signal. In thi
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This research aims to know the effect of job burnout in the worker’s performance. The researcher presented a theoretical basis for job burnout and the worker's performance. In order to achieve the objectives of the research, a hypothesis was drawn up that determines the nature of the relationship between the independent variable of job burnout and its dimensions (reduced personal accomplishment, depersonalization, Emotional Exhaustion) and variable dependent performance of workers dimensions (productivity, job satisfaction, organizational commitment, creativity), And to represent the volume of this community according to (de Morgan, D. Morgan) glo
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The current research aims to reveal the strength of education and the direction of the relationship between the formal thinking and learning methods of Kindergarten department students. To achieve this objective, the researcher developed a scale of formal thinking according to the theory of (Inhelder & Piaget 1958) consisting of (25) items in the form of declarative phrases derived from the analysis of formal thinking skills based on a professional situation that students are expected to interact with in a professional way. The research sample consisted of (100) female students selected randomly who were divided into four groups based on the academic stages, the results revealed that The level of formal thinking of the main sample is
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