Survival Analysis of Bridge Superstructures in Wisconsin

Although survival analyses have long been used in biomedical research, their application to engineering in general, and bridge engineering in particular, is a more recent phenomenon. In this research, survival (reliability) of bridge superstructures in Wisconsin was investigated using the Hypertabastic accelerated failure time model. The 2012 National Bridge Inventory (NBI) data for the State ofWisconsin were used for the analyses. A recorded NBI superstructure condition rating of 5 was chosen as the end of service life. The type of bridge superstructure, bridge age, maximum span length (MSL) and average daily traffic (ADT) were considered as possible risk factors in the survival of bridge superstructures. Results show that ADT and MSL can substantially affect the survival of bridge superstructures at various ages. The reliability of Wisconsin superstructures at the ages of 50 and 75 years is on the order of 63% and 18%, respectively, when the ADT and MSL values are at Wisconsin’s mean values

Conditional survival analysis for concrete bridge decks

Bridge decks are a significant factor in the deterioration of bridges, and substantially affect long-term bridge maintenance decisions. In this study, conditional survival (reliability) analysis techniques are applied to bridge decks to evaluate the age at the end of service life using the National Bridge Inventory records. As bridge decks age, the probability of survival and the expected service life would change. The additional knowledge gained from the fact that a bridge deck has already survived a specific number of years alters (increases) the original probability of survival at subsequent years based on the conditional probability theory. The conditional expected service life of a bridge deck can be estimated using the original and conditional survival functions. The effects of average daily traffic and deck surface area are considered in the survival calculations. Using Wisconsin data, relationships are provided to calculate the probability of survival of bridge decks as well as expected service life at various ages. The concept of survival dividend is presented and the age when rapid deterioration begins is defined

Survival Analyses for Bridge Decks in Northern United States

The use of deicing salts in northern regions of the United States is a major contributor to the long-term deterioration of bridge decks. In this study, the 2008 U.S. National Bridge Inventory (NBI) records were used to develop survival models for non-reconstructed bridge decks in six northern states of Minnesota, Wisconsin, Michigan, Ohio, Pennsylvania, and New York. The hypertabastic accelerated failure model was used to develop survival (reliability) and hazard (failure rate) functions for all six states. The NBI parameters included were the deck rating, type of superstructure (concrete or steel), deck surface area, age, and average daily traffic (ADT). A recorded NBI deck rating of 5 was considered to be the end of service life. Results show that ADT and deck surface area are both important factors affecting reliability and failure rates in all six states studied. In general, deck reliability and failure rates correspond reasonably well with qualitative measure of the harshness of each state’s winters. The type of superstructure has a varied influence in different states. It is recommended that deck area and ADT be considered as important factors when planning maintenance operations

Investigation of Flow Pattern in the Vicinity of Lateral Intake at the U-Shape Bend Channels

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Hyperbolastic growth models: theory and application

BACKGROUND: Mathematical models describing growth kinetics are very important for predicting many biological phenomena such as tumor volume, speed of disease progression, and determination of an optimal radiation and/or chemotherapy schedule. Growth models such as logistic, Gompertz, Richards, and Weibull have been extensively studied and applied to a wide range of medical and biological studies. We introduce a class of three and four parameter models called "hyperbolastic models" for accurately predicting and analyzing self-limited growth behavior that occurs e.g. in tumors. To illustrate the application and utility of these models and to gain a more complete understanding of them, we apply them to two sets of data considered in previously published literature. RESULTS: The results indicate that volumetric tumor growth follows the principle of hyperbolastic growth model type III, and in both applications at least one of the newly proposed models provides a better fit to the data than the classical models used for comparison. CONCLUSION: We have developed a new family of growth models that predict the volumetric growth behavior of multicellular tumor spheroids with a high degree of accuracy. We strongly believe that the family of hyperbolastic models can be a valuable predictive tool in many areas of biomedical and epidemiological research such as cancer or stem cell growth and infectious disease outbreaks

Hyperbolastic modeling of tumor growth with a combined treatment of iodoacetate and dimethylsulphoxide

<p>Abstract</p> <p>Background</p> <p>An understanding of growth dynamics of tumors is important in understanding progression of cancer and designing appropriate treatment strategies. We perform a comparative study of the hyperbolastic growth models with the Weibull and Gompertz models, which are prevalently used in the field of tumor growth.</p> <p>Methods</p> <p>The hyperbolastic growth models H1, H2, and H3 are applied to growth of solid Ehrlich carcinoma under several different treatments. These are compared with results from Gompertz and Weibull models for the combined treatment.</p> <p>Results</p> <p>The growth dynamics of the solid Ehrlich carcinoma with the combined treatment are studied using models H1, H2, and H3, and the models are highly accurate in representing the growth. The growth dynamics are also compared with the untreated tumor, the tumor treated with only iodoacetate, and the tumor treated with only dimethylsulfoxide, and the combined treatment.</p> <p>Conclusions</p> <p>The hyperbolastic models prove to be effective in representing and analyzing the growth dynamics of the solid Ehrlich carcinoma. These models are more precise than Gompertz and Weibull and show less error for this data set. The precision of H3 allows for its use in a comparative analysis of tumor growth rates between the various treatments.</p

Field Study of Morphological Parameters in Step-Pool Streams

Nowadays, step-pool formations have attracted a lot of attention, which are distinguished by the successive arrangements of the bed, suitable geometry, and the tumbling flow pattern, which can highly disperse water energy. Field study of a step–pool channel, along with one of the upper reaches of Kamandan River indicated a strong correlation between several morphological parameters of the river such as reach slope, step length, step height, pool depth, local slope, and the like. The length of the reach under the study is 145 meters and has an intermediate morphology based on Montgomery and Buffington’s classification. Therefore, twelve distinct step units were identified for 145 meters upstream while the rest was formed by steep morphology. In the present study, different definitions of wave length were applied to establish the relationships among the above parameters. For instance, the difference between apexes of every two successive step elevation was found to have a considerable relationship with the wavelength with a determination coefficient of 0.9. In addition, bankfull width and depth, along the profile for different cross-sections, were determined to establish a relationship between these parameters and pool spacing. Further, the parameters were applied to create a relationship with step heights

Role of S̲̲hayk̲̲h Muḥammad K̲̲hiyābānī and the Democratic Movement of Azerbaijan in the socio-political history of Iran 1910-1920

I was interested in history while I was in school and I pursued this interest as a history student at the University of Tabriz where I graduated in history in 1973. Apart from a major part of our studies in history, which were about the Iranian and foreign dynasties, we had to study a great deal about the lives of individual Kings; but hardly any space was allocated to the history of social and political movements in Iran. The names of patriots and political thinkers such as K̲h̲iyābānī were not, for political reasons, mentioned. These movements, however, no matter how briefly they were covered in our history books, were still able to arouse my curiosity and interest in discovering more about these movements and their leaders. In 1977 I decided to undertake research in modern history. My decision coincided with social and political upheavals in Iran which resulted in the revolution of 1979. This by itself strengthened my conviction that we must study and understand our history in its particular social and political content. That is to say revolts and revolutions are not something which appear suddenly, but are the product and result of historical developments in which peoples, as a living force, have taken part. These revolts and revolutions are, in fact, the manifestations of longstanding social injustices and oppressions which have been imposed on the people by despotic kings, irresponsible governments and reactionary rulers. In recent social upheavals of Iran I witnessed how thousands of sincere people and patriots gave their lives and wished to free their country from age old backwardness. This reflected the continuation of the constitutional revolution and K̲h̲iyābānī's uprising (1910-1920). Since my grandfather Mīrzā Muḥammad Tagī Ṭabāṭabā'ī K̲h̲ātambak̲hs̲h̲ was involved in the constitutional revolution and K̲h̲iyābānī's uprising and I naturally had heard a lot about K̲h̲iyābānī through my relatives, both personal curiosity and historical interest made me choose K̲h̲iyābānī as the subject of my research. Some books and articles have been written about K̲h̲iyābānī which are either very superficial or based on misrepresentation. They are superficial because they have not attempted to explain why and how K̲h̲iyābānī's uprising began and the reasons for its success and failure and the role of central government in Tehran in this event is not examined. K̲h̲iyābānī's original speeches and works have not been studied in depth. The opposition to K̲h̲iyābānī's uprising has misrepresented him in different ways. The most striking aspect of this is the fact that he has been accused by his political opponents over and over again of being a "separatist". Some historians have even either spelt K̲h̲iyābānī's name wrongly or copied the errors of others. I came to Edinburgh and was accepted as a postgraduate student in October 1979, and then went to London where I studied and examined the British Foreign office archives and also studied in the British Library. Through the Edinburgh University Library I received some books and newspapers in Russian, French, English, Persian and Azari. Three times I travelled to Iran where I could consult the Iranian Parliamentary documents, newspapers, books and interviewed a number of Iranians who either participated in or had valuable memories of K̲h̲iyābānī's uprising. It is hoped, therefore, that the present study will shed a great deal of light upon a hitherto much-neglected episode in modern Iranian history

Long term performance of gravel base course layers in asphalt

This research investigated the performance of base layer aggregates in HMA pavements using laboratory tests (standard compaction, particle size analysis, Atterberg Limits, sodium sulfate soundness, Micro-Deval abrasion, absorption, specific gravity, and soaked CBR) on existing base layer materials as well as pavement surface visual and automated distress surveys. The purpose of this research was to investigate potential degradation of aggregate bases, strength variations over time, and the likely causes for both. Analysis of laboratory and field test results indicated significant variability in the properties and characteristics of base layer aggregate materials in various pavement test sections. Based on the results of the laboratory and field tests, the research team believes that the long-term performance of the base layer aggregates impacted the overall pavement performance of the corresponding test sections. While base aggregate materials in general did not exhibit severe degradation or disintegration – as demonstrated by laboratory tests – nor significant contamination from subgrade, the performance of such materials was lower compared with typical crushed stone materials

Hypertabastic survival model

A new two-parameter probability distribution called hypertabastic is introduced to model the survival or time-to-event data. A simulation study was carried out to evaluate the performance of the hypertabastic distribution in comparison with popular distributions. We then demonstrate the application of the hypertabastic survival model by applying it to data from two motivating studies. The first one demonstrates the proportional hazards version of the model by applying it to a data set from multiple myeloma study. The second one demonstrates an accelerated failure time version of the model by applying it to data from a randomized study of glioma patients who underwent radiotherapy treatment with and without radiosensitizer misonidazole. Based on the results from the simulation study and two applications, the proposed model shows to be a flexible and promising alternative to practitioners in this field