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Application of Ranked Set Sampling to Normality Tests
Get PDFThe normality assumption is used in many statistical analyses and is also a fundamental concept in statistics. Because of this there are many statistical tests for testing the normality assumption. Two of the most primitive ones are the R and Z tests. The main aim of this study is to investigate the application of ranked set sampling to these tests. Therefore, by using the idea of ranked set sampling, modifications of the R and Z tests are considered. Using simulations the results of these new tests are discussed
Numerical Study of Buoyancy Natural Convection in An Open Cavity
Get PDFNumerical study of buoyancy natural convection in open building rooms has been performed using Lattice Boltzmann Method (LBM). The right wall of the room is open, bottom is hot and the other walls are adiabatic. Numerical results are presented in terms of isotherms, streamlines and average Nusselt number to investigate the effects of various Rayleigh numbers and aspect ratios on heat transfer and fluid flow. It is concluded that as the aspect ratio decreases maximum rate of heat transfer happens when Rayleigh number increases
Relaxometric Study Concerning the Action of A Complexant Agent on Petroleum
Get PDFApplying a complexant agent to the contention and bioremediation of petroleum spills, although important for industry, is very rare. Therefore, the aim of this paper is to present a study concerning the influence of a complexant agent, namely chitosan, on petroleum using time-domain nuclear magnetic resonance (TD-NMR). Alterations in the transverse relaxation time (T2) values and peak areas were observed, inferring that the interaction of the complexant agent with petroleum causes destabilization, precipitation of chemical compounds and separation of phases (water and oil). Thus, a novel application involving this spectroscopic technique in the energy field is presented
CFD Benchmark Tests for Indoor Environmental Problems: Part 3 Numerical Thermal Manikins
Get PDFRecent indoor environmental design is requested to create comfortable and safety space in addition to the maximizing the energy conservation performance in buildings. In this point of view, it is important to enhance the prediction accuracy of indoor environmental quality in design stage. Commercial Computational Fluid Dynamics (CFD) software is practically applied in indoor environmental design recent years but the prediction accuracy of CFD simulation depends on the understanding for the fundamentals of fluid dynamics and the setting of appropriate boundary and numerical conditions as well. The series of this study aimed to provide with the practical information such as prediction accuracy and problematic areas related to CFD applications in indoor environment, air conditioning and ventilation, and then performed benchmark tests and reported the results. Especially in this Part 3, benchmark test results for numerical thermal manikins were introduced. SST k-ω model with fine mesh could provide sufficient accurate results and showed good agreement with experimental results
Development of Transient Differential Model of Bell-Delaware Method with A Case Study of Water/TiO2 Nanofluid
Get PDFHeat exchangers are equipments designed for efficient and economic thermal energy transfer between chemical process flows, being widely applied in chemical plants, petrochemical, refinery and power plants. This work aims the development of a rigorous transient model for a 1-2 shell-and-tube of heat exchangers with fractionated baffles, implementing Bell-Delaware method to determine the thermal and fluid dynamics parameters like heat transfer coefficients and pressure drop. For this, Bell-Delaware method has been utilized to the shell-side, considering several types of baffle leaks and its configuration, bypass effect in tube bundles, different input and output distances of baffles, laminar flow, temperature gradient and viscosity variation near the tubes walls. Nanofluid physical properties were locally evaluated by adapted prediction equations available in databases and literature. The case study simulations were performed using the Python computer program and its modules, to determine temperature and physical properties and profiles of TiO2 nanofluid through the tube, considering a one-dimensional variation, and showing the model applicability for dimensioning and analysis of shell-and-tube 1-2 exchangers
Transient Analysis of Coupled Natural Convection and Surface Thermal Radiation in a Tilted Open Cavity
Get PDFNumeric results of the transient heat transfer by natural convection and surface thermal radiation in a tilted open cavity are presented. The conservation equations in primitive variables are solved using the finite volume method and the SIMPLEC algorithm. The transient results are obtained for a Rayleigh number of 106 and five inclination angles (0°, 45°, 90°, 120° and 180°. The numerical model predicts flow instabilities for inclination angle of 0°, which avoids reaching the steady state. The steady state is reached after a long time for ϕ=180°
Effect of Collector Tilt Angle on the Performance of a Residential Solar-Heating-and-Cooling System
Get PDFA residential solar-heating-and-cooling (SHC) system is a possible alternative for the reduction of fossil fuel consumption to cover residential energy loads. These systems can cover all thermal loads, i.e. space heating, space cooling and domestic hot water preparation. Space cooling is fulfilled through a heat-activated (hot water), single-effect LiBr-water absorption chiller. Proper operation of such a system requires coupling of the solar collector array to a hot water storage tank with auxiliary heating. Auxiliary heating, in this case in the form of a diesel-fired boiler, is necessary to supplement heating in the storage tank when demand exceeds solar heating availability. In this study emphasis is given on the effect of the collector tilt angle (slope) on the performance of a SHC system. A constant slope throughout the year simplifies system configuration and maintenance, but on the other hand a variable slope improves performance, in terms of energy efficiency, and thereby lowers the operating cost of auxiliary heating. The results of the study show that it is economically beneficial to vary the slope throughout the year (on a monthly basis), since $233/year can be saved when a variable slope is used
Catalytic Removal of Volatile Organic Compounds over Porous Catalysts
Get PDFIn this review, we summarize the recent research progress on the preparation and catalytic performance of meso- and macroporous metal oxide or mixed metal oxide (including manganese oxides, cobalt oxides, iron oxides, chromium oxides, and perovskite-type oxides) catalysts and their supported transition metal and noble metal catalysts for the oxidative removal of typical volatile organic compounds (VOCs), which were prepared using the hard-templating and polyvinyl alcohol-protected reduction methods, respectively. Most of these porous catalysts performed well for the addressed reactions, which was associated with their surface areas, adsorbed oxygen species concentrations, low-temperature reducibility, interactions between noble metal or metal oxide and support as well as porous structures. In addition, the perspectives for developing high-performance catalytic materials and novel VOCs removal technologies are also proposed
Monsoon Season Rain Prediction for the Year 2015 for Telangana, India Based on Telangana’s Historical Rain Data
Get PDFIn this work the prediction of rain is based on average of two methods. In these methods, historical rain data of Telangana from 1981 to 2012 are selected for projection. These methods take into account the trends in rain pattern also. Among the results are the effects of El Nino and La Nina which for Telangana are not as significant as compared to higher frequencies on annual rainfall basis. The period of these combined effects (El Nino and La Nina) is 10.67 years. The average rainfall of Telangana is 70 centimeters (cms). The normal range of rain varies between the mean+standard deviation as per the Indian Meteorological Department (IMD). The forecast is being made in November 2014 for the Year 2015 that the rain will be normal in the month of June whereas some excess rain will take place in later months as shown in Tables 1 to 5 here. The advantage of this approach is that it gives farmers far more time than they get presently when preliminary predictions are announced by Indian Meteorological Department in April for each monsoon
Periodic Solutions for Damped Vibration Problems
Get PDFIn this paper we are concerned with the following damped vibration problem where ,  with  and ,  is -periodic in  such that  is a -periodic, positive definite symmetric matrix and  satisfies the global Ambrosetti-Rabinowitz condition or is subquadratic at infinity. By use of the Mountain Pass Theorem or the genus properties in the critical theory, we establish some new criteria to guarantee the existence and multiplicity of periodic solutions. Recent results in the literature are generalized and significantly improved