509 research outputs found

    Deformation behavior of flexible pavements by finite element simulation

    Get PDF
    Flexible pavement is usually designed based on certain axle load limits and climatic conditions. The Iraqi code has specified certain load limits per each axle type that should not be exceeded. However, many trucks violate these limits by carrying additional weights to decrease the transportation cost. These overweight trucks cause severe deterioration to the pavement and thus reduce its life. The Iraqi authorities generally charges the violating trucks a penalty based on their weights. This penalty could be very small compared to the damage occurring to the pavement based on these over weights. Also, some trucks may carry huge weights that the pavement may not support, so unloading such trucks could be a suitable solution rather than paying few amounts of money and deteriorating the pavement. The study aims at studying the effect of axle load increase, and the variation in pavement moduli, on the overall pavement life. It also aims to estimate the overweight truck limits that could be penalized or unloaded. The research uses the ABAQUS software conditions to estimate the tensile strains occurring under the asphalt concrete (AC) layer and the compressive strains above the subgrade surface. These computed strains are incorporated in the fatigue cracking and rutting models to estimate the pavement life for different axle weights. Results showed that violating trucks should be unloaded when their weights exceed certain limits

    Hepatic Cryotherapy and Subsequent Hepatic Arterial Chemotherapy for Colorectal Metastases to the Liver

    Get PDF
    This paper presents an experience of thirty consecutive patients with hepatic colorectal metastases who were treated with hepatic cryotherapy and subsequent hepatic arterial infusion (HAI) chemotherapy using 5FU

    Empirical analysis of rough set categorical clustering techniques based on rough purity and value set

    Get PDF
    Clustering a set of objects into homogeneous groups is a fundamental operation in data mining. Recently, attention has been put on categorical data clustering, where data objects are made up of non-numerical attributes. The implementation of several existing categorical clustering techniques is challenging as some are unable to handle uncertainty and others have stability issues. In the process of dealing with categorical data and handling uncertainty, the rough set theory has become well-established mechanism in a wide variety of applications including databases. The recent techniques such as Information-Theoretic Dependency Roughness (ITDR), Maximum Dependency Attribute (MDA) and Maximum Significance Attribute (MSA) outperformed their predecessor approaches like Bi-Clustering (BC), Total Roughness (TR), Min-Min Roughness (MMR), and standard-deviation roughness (SDR). This work explores the limitations and issues of ITDR, MDA and MSA techniques on data sets where these techniques fails to select or faces difficulty in selecting their best clustering attribute. Accordingly, two alternative techniques named Rough Purity Approach (RPA) and Maximum Value Attribute (MVA) are proposed. The novelty of both proposed approaches is that, the RPA presents a new uncertainty definition based on purity of rough relational data base whereas, the MVA unlike other rough set theory techniques uses the domain knowledge such as value set combined with number of clusters (NoC). To show the significance, mathematical and theoretical basis for proposed approaches, several propositions are illustrated. Moreover, the recent rough categorical techniques like MDA, MSA, ITDR and classical clustering technique like simple K-mean are used for comparison and the results are presented in tabular and graphical forms. For experiments, data sets from previously utilized research cases, a real supply base management (SBM) data set and UCI repository are utilized. The results reveal significant improvement by proposed techniques for categorical clustering in terms of purity (21%), entropy (9%), accuracy (16%), rough accuracy (11%), iterations (99%) and time (93%). vi

    Factors Affecting Current Ratings for Underground and Air Cables

    Get PDF
    The aim of this paper is to present a parametric study to determine the major factors that influence the calculations of current rating for both air and underground cables. The current carrying capability of the power cables rely largely on the installation conditions and material properties. In this work, the influences on ampacity of conductor size, soil thermal resistivity and ambient soil temperature for underground installations are shown. The influences on the current-carrying capacity of solar heating (time of day effects and intensity of solar radiation), ambient air temperature and cable size for cables air are also presented. IEC and IEEE standards are taken as reference

    Incidence trends of lung and gastroenteropancreatic neuroendocrine neoplasms in Switzerland.

    Get PDF
    The incidence of neuroendocrine neoplasms (NENs) seems to increase worldwide. Long-term, population-based series that consider tumor differentiation are, however, sparse. We assessed the incidence trend of lung and gastroenteropancreatic (GEP) NENs according to the latest International Agency for Research on Cancer/World Health Organization classification over a 41-year time period in two Swiss regions. All cases of lung and GEP NENs recorded in the Vaud and Neuchâtel Cancer Registries from 1976 to 2016 were included. NENs were stratified into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Changes in annual age-standardized incidence rates were calculated for lung and GEP NETs and NECs by sex. Of 4,141 patients diagnosed with NENs, 65% were men. The incidence of lung NETs among men and women increased by 3.9%/year (95% CI: -5.3, 14.1%) and 4.9%/year (0.1, 9.9%), respectively, between 1976 and 2016. The incidence of lung NECs decreased by 2.6%/year (-3.1,-1.8%) in men from 1985 to 2016 whereas it increased in women between 1976 and 1998 by 6%/year (4.2, 7.9%). For GEP NETs, a steady annual increase in incidence occurred between 1976 and 2016 with a magnitude of 1.7% (0.7, 2.7%) in men and 1.3% (0.5, 2.1%) in women. No significant trend in incidence of GEP NECs was found for both sexes. The incidence trends of lung NECs in men and women parallel changes in smoking prevalence in the population. Causes of the increase in incidence of GEP NETs are likely multifactorial. Our study supports the importance of evaluating the epidemiology of NENs by tumor differentiation

    Incidence trends of lung and gastroenteropancreatic neuroendocrine neoplasms in Switzerland

    Get PDF
    The incidence of neuroendocrine neoplasms (NENs) seems to increase worldwide. Long-term, population-based series that consider tumor differentiation are, however, sparse. We assessed the incidence trend of lung and gastroenteropancreatic (GEP) NENs according to the latest International Agency for Research on Cancer/World Health Organization classification over a 41-year time period in two Swiss regions. All cases of lung and GEP NENs recorded in the Vaud and Neuch\ue2tel Cancer Registries from 1976 to 2016 were included. NENs were stratified into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Changes in annual age-standardized incidence rates were calculated for lung and GEP NETs and NECs by sex. Of 4,141 patients diagnosed with NENs, 65% were men. The incidence of lung NETs among men and women increased by 3.9%/year (95% CI: -5.3, 14.1%) and 4.9%/year (0.1, 9.9%), respectively, between 1976 and 2016. The incidence of lung NECs decreased by 2.6%/year (-3.1,-1.8%) in men from 1985 to 2016 whereas it increased in women between 1976 and 1998 by 6%/year (4.2, 7.9%). For GEP NETs, a steady annual increase in incidence occurred between 1976 and 2016 with a magnitude of 1.7% (0.7, 2.7%) in men and 1.3% (0.5, 2.1%) in women. No significant trend in incidence of GEP NECs was found for both sexes. The incidence trends of lung NECs in men and women parallel changes in smoking prevalence in the population. Causes of the increase in incidence of GEP NETs are likely multifactorial. Our study supports the importance of evaluating the epidemiology of NENs by tumor differentiation

    Dual Axis Solar Tracking System for a Parabolic Dish CPU Water Heater

    Full text link
    The solar parabolic dish water heater is highly efficient but has limited hours of work only when sunlight is perpendicular to its surface. Therefore, this work aims to continue the work of the solar parabolic dish in the daytime using a dual tracking system, depending on the geographic location of the system (longitude and latitude angles) and using the C # programming language. To verify the effect of the dual-axis solar tracking system, the current study considered two types of solar parabolic dishes, the first was fixed, and the second was a rotating dish (by the dual tracking system). It was observed that the water temperature at the outlet of the tracking type solar water heater is 22% higher than that for the fixed dish type; this means that the proposed system has improved the temperature of water in the heat exchanger. Therefore, the highest water temperature value of about 51.4C was at the outlet of the heat exchanger for the tracking type at 1:00 pm, while the temperature recorded for the fixed type was about 46.1C. The highest energy gained from the solar heating system was at 1:00 pm for both types, which was about 76.9 W from the tracking type and 54.7 W from the fixed type. It was also observed that in the fixed dish type, most energy losses occurred during the daytime, while for the tracer of the dish type, useful energy was gained during most of the sunny working hours depending on the solar radiation intensity. © 2021 Institute of Physics Publishing. All rights reserved

    Experimental Study of a Tilt Single Slope Solar Still Integrated with Aluminum Condensate Plate

    Full text link
    The low freshwater productivity of a conventional solar still is considered a challenge for researchers due to the high temperature of the glass cover or basin water depth. In current work, a newly designed solar still was suggested according to the climatic conditions of Yekaterinburg/Russia, which included an enhanced condensation and evaporation process by spraying a thin water film on a hot absorber plate and then passing the generated water vapor by free convection over the aluminum plate (low temperature). The distillation system under study was tested during July 2020 and 29 July was chosen as a typical day from 08:00 a.m. to 8:00 p.m. The results showed that the largest amount of water vapor condenses on the aluminum plate (about 46%), and the rest condenses on the glass cover. This means that the aluminum plate effectively improved productivity due to the flow of humid air naturally (free convection) on the aluminum plate (its surface temperature was lower than that of the glass cover). The cost analytical calculations showed that the cost of producing one liter of distilled water from the suggested solar still was 0.063$. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
    corecore