171 research outputs found
3-Dimensional advanced solution for lunar descent and landing
A 3-dimensional advanced guidance scheme is necessary to perform a successful precise lunar landing mission. This paper outlines a 3-dimensional comparison of diļ¬erent methods of solution of motion control equations for guidance scheme of lunar descent. It also proposes a 3-dimensional advanced solution that allows a full depiction for a descent vehicle motion from orbital states down to the ļ¬nal landing event. In the conventional 2-dimensional methods of solution, some inadequate assumptions exist that limit the validity of the solutions. The proposed research solves those problems and eventually allows a complete representation of the descent module motion for successful pinpoint lunar landing
SERVICE QUALITY DIMENSIONS AND ITS IMPACT ON CUSTOMERāS BEHAVIORAL INTENTIONS
The market of life Insurance has obtained considerabledevelopment with respect to awareness about insurance, terrorism,target killing, and uncertainty in world. In 2014-15, the growth ratewas 29% that showed life Insurance market has a key contribution inPakistanās economy. The core rationale of this research is toinvestigate the services quality aspects and its influence on corporatecustomerās behavioral intentions. This research has two objectivesfirst; determine the perceptions of corporate customers concerningthe quality service of group life insurance. Second, is to examine thebehavioral intentions of corporate customers with respect to numerousaspects of service quality. About 218 responses from corporatecustomers are gathered with the help of structured questionnairesand by using simple random sampling method. The major antecedentsāof behavioral intentions are personalized competence and planning.Conversely, in this study, assurance is not found as a predictor ofbehavioral intention of corporate customers. This is first study in theperspective of group life insurance in Asia as well as in the context ofdeveloping country
Prevalence of Congenital Heart Disease in Infants of Diabetic Mothers in Children Welfare Teaching Hospital
Background: Women with diabetes in pregnancy (type 1, type 2 and gestational) are at increased risk for adverse pregnancy outcomes which also include infant development of congenital heart disease and even fetal death. Adequate glycemic control before and during pregnancy is crucial to improve outcome. Aim of the study: to observe the significance of the cardiac complication seen in new born of diabetic mother and its relation to glycemic control. Patients and methods: This prospective study was conducted in the nursery care unit in children welfare teaching hospital from the period 1st of July 2014 till 30th of June 2015 where one hundred newborns of diabetic mother were collected and screened by echocardiography for congenital heart disease. Those mothers were classified according to White classification, and the babies were classified according to their maturity to (full term, pre term and post term), in reference to their mode of delivery (Spontaneous vaginal delivery or caesarian section) and to their body weight. Results: One hundred newborns where collected, 61 male and 39 female. Male to female ratio was 1.5:1; 60% were normal with no cardiac complication, 40% had congenital heart disease, hypertrophic cardiomyopathyĀ 23%, atrial septal defect 7 %, patent ductus arteriosus 3% and ventricular septal defect 2%, 1% Transposition of great arteries, 1% Trancus arteriosus, 1% Double outlet right ventricle, 1% Tricuspid atrasia and 1% coartication of aorta, it was found that there is a significant relationship between the type of diabetes of the mother and the development of congenital heart disease in infants (p value 0.02); the degree of glycemic control according to HBA1c of the motherĀ and development of congenital heart disease in infants (p value 0.005); birth weight of the infants and the congenital heart disease (p value 0.023), death was reported in only 2%. Conclusions: Hypertrophic cardiomyopathy was the most common type of congenital heart disease in infants of diabetic mothers. Most of infants of diabetic mothers were full term, delivered by caesarian section and their birth weights were more than 4 kg; Congenital heart disease in infants were more common in mothers with uncontrolled diabetes during pregnancy. Pregestational diabetes mellitus mothers are more liable to deliver babies with congenital heart disease than those with gestational diabetes mellitus. Keywords: Congenital heart disease, Hypertrophic cardiomyopathy, Type 1 diabetes, Type 2 diabetes, Gestational diabetes
Scanning Electron Microscopic Studies of Microwave Sintered Al-SiC Nanocomposites and Their Properties
Al-metal matrix composites (AMMCs) reinforced with diverse volume fraction of SiC nanoparticles were synthesized using microwave sintering process. The effects of the reinforcing SiC particles on physical, microstructure, mechanical, and electrical properties were studied. The phase, microstructural, and surface analyses of the composites were systematically conducted using X-ray diffraction (XRD), scanning electron microscope (SEM), and surface profilometer techniques, respectively. The microstructural examination revealed the homogeneous distribution of SiC particles in the Al matrix. Microhardness and compressive strength of nanocomposites were found to be increasing with the increasing volume fraction of SiC particles. Electrical conductivity of the nanocomposites decreases with increasing the SiC content. ? 2018 M. A. Himyan et al.This publication was made possible by NPRP Grant 7159-2-076 from Qatar National Research Fund (a member of the Qatar Foundation).Scopu
Positional control of rotary servo cart system using generalized dynamic inversion
This paper presents the design approach of Generalized Dynamic Inversion (GDI) for angular position control of SRV02 rotary servo base system. In GDI, linear first order constraint differential equations are formulated based on the deviation function of angular position and its rate, and its inverse is calculated using Moore-Penrose Generalized Inverse to realize the control law. The singularity problem related to generalized inversion is solved by the inclusion of dynamic scaling factor that will guarantee the boundedness of the elements of the inverted matrix and stable tracking performance. Numerical simulations and real-time experiment are performed to evaluate the tracking performance and robustness capabilities of the proposed control law considering nominal and perturbed model dynamics. For comparative analysis, the results of GDI is compared with conventional PID control. Simulation and experimental results demonstrate better angular position tracking for the square-wave and sinusoidal waveforms, which reveals the superiority, and agility of GDI control over conventional PID
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Automotive leaf spring design and manufacturing process improvement using failure mode and effects analysis (FMEA)
Nowadays human safety and comfort are the most considerable parameters in designing and manufacturing of a vehicle, that is why every organization ensures the quality and reliability of components used in the vehicle. Leaf spring is also a component of vehicle which plays an important role in human safety and comfort. It acts as a structural member and an integral part of suspension system. It is important to eliminate the failures in designing and manufacturing process of leaf springs because of its importance in functionality and safety of vehicle. In this research, failure mode and effects analysis has been used to analyze and reduce the risks of 42 possible failures that can occur in automotive leaf spring. It starts from determining, classifying, and analyzing all potential failures and then rating them with the help numeric scores. The four numeric scores namely severity, occurrence, detection, and Risk Priority Number (RPN) are used to find the high potential failures of semi-elliptical leaf springs. In the end, actions are recommended for RPN greater than 250, to increase quality and reliably of product. </jats:p
Container shipment demand forecasting in the Australian shipping industry: A case study of asiaāoceania trade lane
Demand forecasting has a pivotal role in making informed business decisions by predicting future sales using historical data. Traditionally, demand forecasting has been widely used in the management of production, staffing and warehousing for sales and marketing data. However, the use of demand forecasting has little been studied in the container shipping industry. Improved visibility into the demand for container shipments has been a long-held objective of industry stakeholders. This paper addresses the shortcomings of both short-term and long-term shipment demand forecasting for the Australian container shipping industry. In this study, we compare three forecasting models, namely, the seasonal auto-regressive integrated moving average (SARIMA), HoltāWintersā seasonal method and Facebookās Prophet, to find the best fitting model for short-term and long-term import demand forecasting in the Australian shipping industry. Demand data from three years, i.e., 2016ā2018, is used for the AsiaāOceania trade lane. The mean absolute percentage error (MAPE), root mean squared error (RMSE) and 2-fold walk-forward cross-validation are used for the model evalua-tion. The experiment results observed from the selected metrics suggest that Prophet outperforms the other models in its comparison for container shipment demand forecasting
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