347 research outputs found

    Estimation of longitudinal stability and control derivatives for an icing research aircraft from flight data

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    The results of applying a modified stepwise regression algorithm and a maximum likelihood algorithm to flight data from a twin-engine commuter-class icing research aircraft are presented. The results are in the form of body-axis stability and control derivatives related to the short-period, longitudinal motion of the aircraft. Data were analyzed for the baseline (uniced) and for the airplane with an artificial glaze ice shape attached to the leading edge of the horizontal tail. The results are discussed as to the accuracy of the derivative estimates and the difference between the derivative values found for the baseline and the iced airplane. Additional comparisons were made between the maximum likelihood results and the modified stepwise regression results with causes for any discrepancies postulated

    Irrigation and drainage in the new millennium

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    Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Includes bibliographical references.A field study was conducted at Mashtul Pilot Area MPA (260 feddans' 1 feddan = 4200 m2) situated at north Zagazig to evaluate the performance of the long term constructed subsurface drainage system. The evaluation of grades, alignment and clogging of drain lines can give an indication of the system performance and efficiency. Three drainage units served by the same collector were selected. Four 30 m interval PVC lateral pipes were installed at different depths. The results revealed that, the collector drain slopes were either steep or flat while the overall slope of the collector drain was considered steep for about 45.50% of the sections and flat for the rest. On the other hand, some sections showed an inverse slope which can cause a decrease in the discharge rate. The regularity was classified as good for about 82% of the sections and moderate for the rest. The slope of the lateral drains was correct for 41.7% of those under study (12 lateral drains), steep for 16.60%, and flat for the rest, and the regularity was classified as poor except lateral number 71 which had moderate regularity in the first approach while, in the second approach 41.67% had moderate regularity and poor for the rest. Also the deviation of the drain pipes from the straight line was generally larger than pipe diameter. Consequently, air entrapment and sedimentation resulted. The results also indicated that, the average height of sedimentation inside lateral drains was 12.70 mm (618.30 gm/m drain length) while for collector drains, sediment was in 22.88% of pipe diameter. The average reduction in discharge capacity due to sedimentation for laterals and collectors upstream and downstream parts were 17.17%, 32.80% and 17.60% respectively. Also using Manning, Visser and Wesseling equations leads to different safety factors

    Modification of Microclimate for Better Growth and Develop of Summer Tomato Crop

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    Tomato cultivars grown in Sudan are affected by the hot dry  summer climate and are highly susceptible to Tomato Yellow leaf  Curl Virus disease (TYLCV). Modification of the microclimate may decrease the effects of the hot dry conditions and improve develop- ment and yield of summer tomatoes. The present study was conducted ducted during the summer of 1998 and 1999 at the Gezira University Farm, Wad Medani, Sudan, to investigate the effects of two type of shelterbelts (Abusabeen and pigeon pea) and two irrigation intervals (3 and 7 days) on growth and development of five tomato cultivars )Omdurman, Gezira 96, Summerset 98, Strain B and Peto 86).  The results showed that the short irrigation interval was effective in  reducing the air temperature compared to long irrigation interval  Abusabeen shelter coupled with the short irrigation interval was effective in improving the microclimate, and that the pigeon pea shelter was effective in conserving soil moisture content under the two irrigation intervals. Tomato cultivars Omdurman, Gezira 96 and Summerset 98 had more vigorous growth, larger canopies and  low percentage of. flower shedding per plant within the two types of shelters under the shorter irrigation interval compared to both long irrigation interval and the control

    Effects of Chemical Preservatives on Weights and Lengths of Bluegill Larvae

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    Measuring the lenghts and weights of live fish larvae can be tedious and time-consuming. This constraint could be alleviated by preserving the fish larvae in appropriate chemicals for later measurements. There is little or no information on the effects of preservatives on Bluegill larvae. The objective of this study was to determine the effects of five different common preservatives on Bluegill larvae. Individual weights and lengths of fish were measured and then the larvae were preserved for 7 or 26 days. Preservatives were 5% formalin, 10% formalin, 30% ethanol at -19 *C, 70% ethanol, and 90% ethanol. Preliminary average weights of the larvae preserved for 7d were 1.63, 1.30, 4.02, -0.63, and -4.15g in 5% formalin, 10% formalin, 30% ethanol at -19 *C, 70% ethanol, and 90% ethanol, respectively. The average lengths for 26d were -0.63, -0.39, -0.12, -0.03, and 0.22 in 5% formalin, 10% formalin, 30% ethanol at -19 *C, 70% ethanol, and 90% ethanol, respectively. This study indicated that 70% ethanol had the least effect on weights and lengths of Bluegill larvae preserved for 7 and 26d.https://bluetigercommons.lincolnu.edu/lucer-pubs/1000/thumbnail.jp

    Location-aware deep learning-based framework for optimizing cloud consumer quality of service-based service composition

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    The expanding propensity of organization users to utilize cloud services urges to deliver services in a service pool with a variety of functional and non-functional attributes from online service providers. brokers of cloud services must intense rivalry competing with one another to provide quality of service (QoS) enhancements. Such rivalry prompts a troublesome and muddled providing composite services on the cloud using a simple service selection and composition approach. Therefore, cloud composition is considered a non-deterministic polynomial (NP-hard) and economically motivated problem. Hence, developing a reliable economic model for composition is of tremendous interest and to have importance for the cloud consumer. This paper provides ā€œA location-aware deep learning framework for improving the QoS-based service composition for cloud consumersā€. The proposed framework is firstly reducing the dimensions of data. Secondly, it applies a combination of the deep learning long short-term memory network and particle swarm optimization algorithm additionally to considering the location parameter to correctly forecast the QoS provisioned values. Finally, it composes the ideal services need to reduce the customer cost function. The suggested framework's performance has been demonstrated using a real dataset, proving that it superior the current models in terms of prediction and composition accuracy

    Controlling quarter car suspension system by proportional derivative and positive position feedback controllers with time delay

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    The active car suspension system is presented here to suppress the vibration of the car by applying proportional derivative (PD) and positive position feedback (PPF) controllers with time delay. The control signal output of the controller is applied electrically to the magneto-rheological (MR) damper or Electrical-rheological (ER) damper which is attached parallel to the passive components to improve the suppression of the vibration. The electrical control signal is produced by electronic circuits or programmable logic controller and the two-position sensor feedback signal which are connected to the controller. The approximate solutions of PD and PPF suspension systems are obtained by applying multiple time scales perturbation method. The effects of parameters variation of both the system and the controllers are investigated to achieve the best performance. Simulation results show good performance of the designed controllers

    Mannose-binding lectin deficiency in preterm neonates

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    Background: Mannose-binding lectin (MBL) is a collagenous protein that plays a role in innate immunity. MBL deficiency is associated with an opsonization defect and has been associated with recurrent infections, especially in immunocompromised individuals. Neonates are considered to be immunocompromised because adaptive immunity has not yet been developed. Objective: This study was done to evaluate the levels of MBL in premature neonates and to determine the relation between MBL deficiency and development of sepsis. Methods: This case- control study was conducted on 64 neonates classified into 2 groups; 39 preterm neonates with gestational age (G.A) <36 weeks and 25 healthy full term neonates. Measurement of mannose-binding lectin (MBL) serum level was done on the first day of life using ELISA technique. Results: Mean MBL plasma level was found to be lower in preterm than full term neonates, yet this difference did not reach statistical significance. There was a negative correlation albeit an insignificant one, between MBL level and GA. The deficient group (those with MBL level ā‰¤0.7Ī¼g/ml) had higher incidence of sepsis, albeit an insignificant one, than the non deficient group. A highly significant positive correlation was demonstrated between MBL plasma level in neonatal and umbilical cord blood samples. Conclusion: Premature neonates have low MBL serum levels which could be measured in either their venous or umbilical cord blood efficiently. Further studies are needed to investigate the relationship between MBL deficiency and neonatal sepsis and whether measuring MBL levels might be used to identify which neonates are prone to infections.Keywords: Mannose binding lectin, neonates, preterm, sepsisEgypt J Pediatr Allergy Immunol 2010;8(2):75-8

    Homocysteine, folic acid and vitamin B12 levels in serum of epileptic children

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    AbstractThe relationship between increased homocysteine (Hcy) level and epileptic seizure remains controversial in human, despite a growing evidence of the pro-convulsive effect of the hyperhomocysteinemia (HHcy) observed in the animal studies. The mechanism of this association with epileptogenesis has not been clearly understood, although there is emerging evidence to support the unfavorable effects of some anti-epileptic drugs (AEDs) on the plasma homocysteine (Hcy) concentrations. The aim of this study was to uncover the relationship between the levels of homocysteine (Hcy), the cofactors involved in its metabolism as folic acid and vitamin B12 and anti-epileptic drugs (AEDs) in epileptic patients. Serum level of homocysteine (Hcy), folic acid and vitamin B12 was measured in 60 patients with idiopathic epilepsy; and its level was compared to 30 healthy children serving as control group. No significant difference was found regarding the plasma homocysteine (Hcy) levels between patients (both receiving anti-epileptics and non anti-epileptic drug users) and controls. Epileptic patients on polytherapy showed higher mean serum levels of homocysteine (Hcy) and lower mean serum levels of folic acid compared to those on monotherapy. However, the mean serum levels of homocysteine (Hcy), vitamin B12 and folic acid showed non significant differences between patients using valproic acid (VPA) or carbamazepine (CBZ). Duration of AED therapy showed a significant positive correlation with mean serum levels of homocysteine (Hcy) and a significant negative correlation with mean serum levels of folic acid. To conclude; AEDs upset the homeostatic balance of homocysteine (Hcy) and its cofactors and cause abnormalities in their serum levels

    Determination of longitudinal aerodynamic derivatives using flight data from an icing research aircraft

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    A flight test was performed with the NASA Lewis Research Center's DH-6 icing research aircraft. The purpose was to employ a flight test procedure and data analysis method, to determine the accuracy with which the effects of ice on aircraft stability and control could be measured. For simplicity, flight testing was restricted to the short period longitudinal mode. Two flights were flown in a clean (baseline) configuration, and two flights were flown with simulated horizontal tail ice. Forty-five repeat doublet maneuvers were performed in each of four test configurations, at a given trim speed, to determine the ensemble variation of the estimated stability and control derivatives. Additional maneuvers were also performed in each configuration, to determine the variation in the longitudinal derivative estimates over a wide range of trim speeds. Stability and control derivatives were estimated by a Modified Stepwise Regression (MSR) technique. A measure of the confidence in the derivative estimates was obtained by comparing the standard error for the ensemble of repeat maneuvers, to the average of the estimated standard errors predicted by the MSR program. A multiplicative relationship was determined between the ensemble standard error, and the averaged program standard errors. In addition, a 95 percent confidence interval analysis was performed for the elevator effectiveness estimates, C sub m sub delta e. This analysis identified the speed range where changes in C sub m sub delta e could be attributed to icing effects. The magnitude of icing effects on the derivative estimates were strongly dependent on flight speed and aircraft wing flap configuration. With wing flaps up, the estimated derivatives were degraded most at lower speeds corresponding to that configuration. With wing flaps extended to 10 degrees, the estimated derivatives were degraded most at the higher corresponding speeds. The effects of icing on the changes in longitudinal stability and control derivatives were adequately determined by the flight test procedure and the MSR analysis method discussed herein
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