A Project Based Approach To Doe In Materials

At Iowa State University, the Materials Science and Engineering Department teaches a course in the statistics of materials. Approximately one third of this two credit course is devoted to the design of experiments (DOE). A relatively brief introduction to the theory of DOE sets the stage for the inclusion of a software package used to assist materials engineers to design and analyze the results of experiments. Texts for engineering statistics (1-3) contain chapters dealing with the design of experiments. Literature in materials journals routinely contains references to DOE (4-8). Coupling these texts and recent articles with some practical exposure to design of experiments and the software used to do this, allows students some exposure to industrial practice. In this course students are assigned a major project (20 % of the grade) to be performed in teams. In this project students are encouraged to draw from their co-op and internship experiences. They are also asked to consider to expand upon experiments encountered in other courses in the curriculum

Crystal Method For Accurate Software Duration Estimation

All projects share one common characteristic that is the projection of ideas and activities into new endeavours. The ever-present element of risk and uncertainty to the events and tasks leading to completion can never be foretold with absolute accuracy. The software projects are different from other projects. Underestimation is the root course of many software projects not being able to meet the deadline, or failure. Some of the reasons for inaccurate estimation are as follows: the traditional model not being able to capture the project in detail, quick and reliable strategic analysis. The influence of human factor is not able to incorporate explicitly. Failure to consider rework phenomenon. Failure to capture dynamic interaction between technical development and management policies

PEMODELAN REGRESI RIDGE PADA KASUS CURAH HUJAN DI KOTA SEMARANG

Rainfall is the amount of water that falls on the surface of the flat ground for acertain period measured in units of height (mm) above the horizontal surface. Theclassification of rainfall is divided into thick, medium, and light. Based on data of2016 Semarang city rainfall for 6 years experienced a significant decrease andincrease. With the data of rainfall Semarang city is very high potential for flooding.Semarang rainfall data tend to be unstable then it will cause problems in rainfalldata. Therefore it is necessary to solve the problem in rainfall data. The purpose ofthis study is to model and know the factors that affect rainfall in the city ofSemarang. The results of multiple regression found problems in Multicollinearity. An appropriate method for overcoming multiko in multiple regression is the ridgeregression. Regression of ridge to stabilize regression coefficient value of deviationof assumption in Multicolinearity. The result of the research to select the best model using the smallest MSE value which in the regex ridge model has MSE value 1.517smaller than the value of MSE in multiple regression of 1,519. While for variables that have significant effect on rainfall is wind speed, while variable temperature, humidity, solar irradiance have a significant influence but have weak effect on rainfall in Semarang city.Keywords: Rainfall, Ridge Regression and Multiple Regressio

Highway Routine Maintenance Cost Estimation for Nevada

State highway agencies are obligated to maintain existing roads for the highway systems to work efficiently and with greater longevity. Every year NDOT is responsible for approximately 13,150 lane miles of existing infrastructure. With that in mind, resources need to be provided to maintain the highway system. The purpose of this research was to estimate annual routine maintenance cost for several typical treatment methods of highways. Five prioritization categories of highways used by NDOT were considered. Linear regression models were developed that present the relationship between costs including total maintenance cost and five maintenance cost components: labor, equipment, materials, manpower and stockpile, and the influencing factors: traffic load, road geometry, pavement structure, and climate. It was expected that the cost model depends on various roadway factors including elevation, number of lanes, age of the pavement, last year of pavement construction work, average daily traffic (ADT), number of trucks, single axial load (ESAL), district work done, and weather conditions. This research undertook the following steps: data review, data correlation check, and ordinary least square regression analysis. Data used for the analysis was extracted from NDOT pavement management system. Five NDOT prioritization categories were used for data processing and the analysis. The regression models incorporated the same parameters used in the NDOT pavement management system; therefore they can be simply combined with the existing database. The analysis conducted in this study indicates that road age is a noteworthy factor for a number of life cycle segments and several maintenance cost activities. The life cycle segments varied with each prioritization category including routine maintenance activities and their schedule. For segments where the roadway age does not appear to be significant, the routine maintenance cost estimate stays constant. Routine maintenance activities may be scheduled at the times that are close to the time when a preventive maintenance or reconstruction is scheduled. This practice is reflected in the cost model that the annual maintenance cost may decline with time and suddenly increase at the end of their life cycle stages. Lastly, recommendations have been made to provide fundamentals for future study needs. Several research needs in the cost estimation model are apparent from this assessment. These include additional information regarding cost model development using various statistical tools, periodical data update, use of a larger sample size, and different approaches for constructing prioritization categories life cycle. Also, historical data should be updated constantly due to changes in the material and construction technology. Further, the construction technology might require more or less steps with certain treatments like chip seal or flush seal. Thus, it is recommended to update the data as major construction or material technology is implemented in the routine maintenance work

Large eddy simulation of mixed convection in a vertical slot and geometrical statistics of wall-bounded thermal flow

Buoyant flows are characterized with unsteady large-scale structures and thus time-dependent large eddy simulation (LES) is generally favored. In this dissertation, to further explore LES for buoyant flow, an LES code based on a collocated grid system is first developed. A multigrid solver using a control strategy is developed for the pressure Poisson equations. The control strategy significantly accelerated the convergence rate. A temperature solver using a fourth-order Runge-Kutta approach is also developed. The LES code is extensively tested before it is applied. Although the collocated grid system will introduce conservation errors, in tests of a steady lid-driven cavity flow and transient start-up flow, the effect of the non-conservation of the collocated grid system was not significant. In LES, the effect of SGS scales is represented by SGS models. A novel dynamic nonlinear model (DNM) for SGS stress is tested using isothermal channel flow at Reynolds number 395. The kinetic energy dissipation and geometrical characteristics of the resolved scale and SGS scale with respect to the DNM are investigated. In general, the DNM is reliable and has relatively realistic geometrical properties in comparison with the conventional dynamic model in the present study. In contrast to a pure advecting velocity field, a scalar (temperature) field displays very different characteristics. The modelling of SGS heat flux has not been as extensively studied as that of SGS stress partly due to the complexity of the scalar transport. In this dissertation, LES for a turbulent combined forced and natural convection is studied. The DNM model and a nonlinear dynamic tensor diffusivity model (DTDM-HF) are applied for the SGS stress and heat flux, respectively. The combined effect of the nonlinear models is compared to that of linear models. Notable differences between the nonlinear and linear SGS models are observed at the subgrid-scale level. At the resolved scale, the difference is smaller but relatively more distinguishable in terms of quantities related to the temperature field. Finally, the geometrical properties of the resolved velocity and temperature fields of the thermal flow are investigated based on the LES prediction. Some universal geometrical patterns have been reproduced, e.g. the positively skewed resolved enstrophy generation and the alignment between the vorticity and vortex stretching vectors. The present research demonstrates that LES is an effective tool for the study of the geometrical properties of a turbulent flow at the resolved-scales. The wall imposed anisotropy on the flow structures and orientation of the SGS heat flux vector are also specifically examined. In contrast to the dynamic eddy diffusivity model, the DTDM-HF successfully predicts the near-wall physics and demonstrates a non-alignment pattern between the SGS heat flux and temperature gradient vector

University of Maine at Orono Catalog for 1976-77, 1977-78, part 1

Part 1 (of 2) of the catalog for the University of Maine for the academic years 1976-77 and 1977-78. Part 1 includes pages 1 - 146, providing information on the Calendar, Board of Trustees, General Information, Student Activities, Admission, Collegiate Descriptions, Canadian Studies, Environmental Studies, College of Arts and Sciences, School of Performing Arts, and the School of Nursing

New dynamic subgrid-scale modelling approaches for large eddy simulation and resolved statistical geometry of wall-bounded turbulent shear flow

This dissertation consists of two parts, i.e. dynamic approaches for subgrid-scale (SGS) stress modelling for large eddy simulation and advanced assessment of the resolved scale motions related to turbulence geometrical statistics and topologies. The numerical simulations are based on turbulent Couette flow. The first part of the dissertation presents four contributions to the development of dynamic SGS models. The conventional integral type dynamic localization SGS model is in the form of a Fredholm integral equation of the second kind. This model is mathematically consistent, but demanding in computational cost. An efficient solution scheme has been developed to solve the integral system for turbulence with homogeneous dimensions. Current approaches to the dynamic two-parameter mixed model (DMM2) are mathematically inconsistent. As a second contribution, the DMM2 has been optimized and a modelling system of two integral equations has been rigorously obtained. The third contribution relates to the development of a novel dynamic localization procedure for the Smagorinsky model using the functional variational method. A sufficient and necessary condition for localization is obtained and a Picard's integral equation for the model coefficient is deduced. Finally, a new dynamic nonlinear SGS stress model (DNM) based on Speziale's quadratic constitutive relation [J. Fluid Mech., 178, p.459, 1987] is proposed. The DNM allows for a nonlinear anisotropic representation of the SGS stress, and exhibits a significant local stability and flexibility in self-calibration. In the second part, the invariant properties of the resolved velocity gradient tensor are studied using recently developed methodologies, i.e. turbulence geometrical statistics and topology. The study is a posteriori based on the proposed DNM, which is different than most of the current a priori approaches based on experimental or DNS databases. The performance of the DNM is further validated in terms of its capability of simulating advanced geometrical and topological features of resolved scale motions. Phenomenological results include, e.g. the positively skewed resolved enstrophy generation, the alignment between the vorticity and vortex stretching vectors, and the pear-shape joint probability function contour in the tensorial invariant phase plane. The wall anisotropic effect on these results is also examined

Analysis of seasonal and day-of-week traffic patterns at national parks

The National Park Service (NPS) is currently contemplating the implementation of a system-wide traffic monitoring program. While several of the national parks within this network collect continuous vehicle data at multiple stations within each park, these programs have not been examined for their efficiency and cost effectiveness. Therefore, as the NPS looks to expand their count program, this thesis investigates potential improvements using a sample set of five parks. To determine whether the national park seasonal and day-of-week traffic patterns exhibit consistency from one year to the next, the seasonal and day-of-week factors were compared across all five years. Using the Kruskal-Wallis test, it was determined that the seasonal and day-of-week factors were not statistically different from 2002 to 2006 for all five national parks. Therefore, it is recommended that the NPS consider reducing the amount of data that they collect by using short-duration counts in conjunction with a modest number of permanent counts. To determine whether data collection efforts can be shared amongst various entities, the national park traffic counts for 2002 to 2006 were compared to those of nearby state highway automatic traffic recorder (ATR) locations using correlation analyses. While the correlation values ranged from “high” to “negligible”, the distance between the park and ATR location had a direct effect on the magnitude of the value. Therefore, in order to achieve the greatest probability that the correlation will be “high”, it is suggested that the NPS share data collection efforts using ATR locations within 20 miles of the park. To determine which design volume calculation method was most appropriate for the parks, design volumes were computed using two methods. Using the traditional Kfactor plot, it was determined that the 30th highest hourly volumes should be used for urban parks as this is where the “knee” occurs. Although this is not the case for rural parks, there is no compelling evidence to suggest a more appropriate design hour. Additionally, the method recommended by AASHTO for recreational roadways resulted in volumes that were frequently exceeded. Therefore, the K-factor plot method is most appropriate for both the urban and rural parks

University of Maine Catalog for 1975-76

The University of Maine catalog for the 1975-76 academic year included the calendar, information about the Board of Trustees, officers, general information, student activities, admission, veterans administration, financial information, scholarships, loans, environmental studies, Canadian studies, programs available through the institution\u27s several colleges, graduate school, military science, athletics, continuing education, summer session, public radio and television, personnel, and a summary of student enrollment. An index appears on page 333