Determination of the unsaturated hydraulic diffusivity of porous construction materials from transient moisture profiles utilizing pin-type resistance sensor array

2005 ◽  
Vol 40 (4) ◽  
pp. 1013-1015 ◽  
Author(s):  
Q. G. Wang ◽  
K. Ahmet ◽  
Y. Yue ◽  
L. Y L
Keyword(s):  
Sensor Array ◽  
Construction Materials ◽  
Hydraulic Diffusivity ◽  
Moisture Profiles

scholarly journals Machine Learning Approaches for Prediction of the Compressive Strength of Alkali Activated Termite Mound Soil

2021 ◽  
Vol 11 (11) ◽  
pp. 4754
Author(s):  
Assia Aboubakar Mahamat ◽  
Moussa Mahamat Boukar ◽  
Nurudeen Mahmud Ibrahim ◽  
Tido Tiwa Stanislas ◽  
Numfor Linda Bih ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Construction Materials ◽  
Curing Temperature ◽  
Sustainable Construction ◽  
Support Vector ◽  
Learning Approaches ◽  
Artificial Neural Network Ann ◽  
Curing Regime ◽  
Alkali Activated

Earth-based materials have shown promise in the development of ecofriendly and sustainable construction materials. However, their unconventional usage in the construction field makes the estimation of their properties difficult and inaccurate. Often, the determination of their properties is conducted based on a conventional materials procedure. Hence, there is inaccuracy in understanding the properties of the unconventional materials. To obtain more accurate properties, a support vector machine (SVM), artificial neural network (ANN) and linear regression (LR) were used to predict the compressive strength of the alkali-activated termite soil. In this study, factors such as activator concentration, Si/Al, initial curing temperature, water absorption, weight and curing regime were used as input parameters due to their significant effect in the compressive strength. The experimental results depict that SVM outperforms ANN and LR in terms of R2 score and root mean square error (RMSE).

Determination of Polymer Type and Content in Concrete Materials by FTIR and TGA

2015 ◽  
Vol 1129 ◽  
pp. 151-158
Author(s):  
Takako Tokura ◽  
Joyce Lim ◽  
Ai Ming Chua ◽  
Wey Liang Lee ◽  
James Wong
Keyword(s):  
Construction Materials ◽  
Attenuated Total Reflection ◽  
Polymer Materials ◽  
Accurate Information ◽  
Fine Aggregate ◽  
Group Information ◽  
Concrete Materials ◽  
Spectrum Matching ◽  
Polymer Type

Polymers are commonly used in concrete materials. The type and concentration of polymer are important information for stakeholders, because they have a critical impact on the properties of concrete materials. Therefore, reliable and accurate information is highly desirable. To this end, Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) are used to analyze polymer contents in construction materials.FTIR spectroscopy is a suitable technique to identify the polymer type using IR spectrum matching. Additionally, functional group information can be easily obtained from each peak. Attenuated Total Reflection (ATR) method can be used to measure extracted polymers from construction materials to obtain IR spectra, and match against the library database to identify the polymer materials. TGA is one of the common thermal analysis methods. It measures the weight loss or gain of sample due to chemical reactions such as vaporization, decomposition and oxidation as a function of temperature. In this paper, we will discuss development of reliable analytical methods with which mixtures of polymer, fine aggregate and cement with different percentages of polymer content were prepared and evaluated.

scholarly journals Characterization of graphite-epoxy composite electrodes for free electrochemical detection of adenine and guanine in DNA

2021 ◽  
Author(s):  
Abel Ibrahim Balbin Tamayo ◽  
Leodanis Correa Fajardo ◽  
Ana Margarita Esteva Guas
Keyword(s):  
Square Wave Voltammetry ◽  
Construction Materials ◽  
Composite Electrodes ◽  
Single Chain ◽  
Electron Transfer Rate ◽  
Redox Probe ◽  
Wave Voltammetry ◽  
Electron Transfer Rate Constant

Graphite-epoxy composites (GECs) are alternative construction materials for electro­chemical sensors. For these materials, the electron transfer rate constant of some redox reaction depends additionally on the stoichiometric relationship between the insulating and conducting phases of the composite. In this work, the influence of dif­fe­rent ratios of araldite/hardener/graphite on the electrochemical properties of GEC electrodes is evaluated for the simultaneous determination of adenine and guanine in the single chain DNA, using the square wave voltammetry technique. Six GEC electro­des were prepared with different ratios of components, and electrochemically charac­terized by cyclic voltammetry in the presence of ferri/ferrocyanide redox couple as a redox probe. GEC electrodes that showed the best electrochemical responses of redox probe were characterized by thermogravimetric analysis (TGA) and used for the simul­taneous determination of free adenine and guanine in a solution, and DNA oligonu­cle­otides. The best results were obtained for GEC electrodes containing twice higher volu­me of araldite resin with respect to the hardener. TGA analysis revealed presence of 15-26 % of resin for these GEC electrodes. The obtained results revealed potential appl­ication of these GEC electrodes as DNA sensors based on the oxidation signal of guanine.

Metal Nano-Oxide based Colorimetric Sensor Array for the Determination of Plant Polyphenols with Antioxidant Properties

2019 ◽  
Vol 53 (4) ◽  
pp. 627-645
Author(s):  
Claudia Valentina Popa ◽  
Alina Vasilescu ◽  
Simona Carmen Litescu ◽  
Camelia Albu ◽  
Andrei Florin Danet
Keyword(s):  
Sensor Array ◽  
Antioxidant Properties ◽  
Colorimetric Sensor ◽  
Plant Polyphenols ◽  
Colorimetric Sensor Array ◽  
Nano Oxide

X-Ray Absorption-Edge Determination of Cobalt in Complex Mixtures*

1961 ◽  
Vol 5 ◽  
pp. 379-388
Author(s):  
E.A. Hakkila ◽  
G.R. Waterbury
Keyword(s):  
Nitric Acid ◽  
Absorption Edge ◽  
Path Length ◽  
Construction Materials ◽  
X Ray ◽  
Relative Standard ◽  
Standard Deviations ◽  
Low X ◽  
X Ray Absorption

AbstractThe application of the X-ray absorption-edge technique was extended to the determination of cobalt in aqueous and alcoholic solutions containing a wide variety of impurity elements. In the procedure developed, secondary radiation from a 50% copper-nickel alloy is passed through an absorption cell filled alternately with the solvent and the sample solution. The transmitted Intensities of the Kα lines for copper and nickel are measured, and the concentration of cobalt is determined using accepted absorption principles. The K absorption edge for cobalt occurs at 1.604 A, restricting cell construction materials and solvents to those containing light elements with low X-ray absorption characteristics and also limiting the path length of the cell.Cells of 0.16- and 0.34-cm path length were used in the analysis of aqueous and alcoholic solutions, respectively. With the 0.16-cm path-length cell, relative standard deviations of 4.6 to 0.5% were obtained for cobalt concentrations ranging from 1.00 to 10.00 mg/ml for known aqueous solutions that contain various known concentrations of nitric acid. With the longer path-length cell, relative standard deviations from 1.8 to 0.46% were obtained for cobalt concentrations in the same range in known alcoholic solutions containing various known concentrations of nitric acid. The standard deviation of determining the blank is 0.043 mg of cobalt per milliliter for the 0.16-cm cell and 0.016 mg of cobalt per milliliter for the longer cell.A Norelco X-ray spectrograph with a three-position head was used in these analyses. Less than 5 min is required to convert this instrument from normal fluorescence operation to absorption-edge analysis. Approximately 15 to 20 analyses can be performed daily.

scholarly journals Analysis of Methods for Determining Climate Loads at a Specified Territory Point by Meteorological Data

2020 ◽  
Vol 14 (2) ◽  
pp. 206-211
Author(s):  
Željko Kos ◽  
Viktor Pashynskyi ◽  
Yevhenii Klymenko ◽  
Mykola Pashynskyi
Keyword(s):  
Meteorological Data ◽  
Construction Materials ◽  
High Energy ◽  
Weather Data ◽  
Opposite Case ◽  
Relative Proximity ◽  
Characteristic Values ◽  
Building Standards ◽  
High Energy Consumption

Methods for determining the characteristic values of climate loads at the location of a building have been perfected. Based on comparative analysis, the method of levelling the values of climate loads with an exponential or triangular weight function is recommended. For four climate loads, appropriate equalization intervals are determined, ensuring the maximum amount of weather data taken into account, while maintaining their uniformity. In construction, the determination of the climate load is important for the location of the building. When prescribing building standards, the values of the climate load are determined according to the data of weather stations in relative proximity, which provides values within the limits of reliability. Such an approach can lead to an overestimation of the characteristic values of climate loads and consequently increase the consumption of the construction materials of the building or, in the opposite case, decrease the unnecessarily high-energy consumption to condition the space inside the building.

Simultaneous determination of fermented milk aroma compounds by a potentiometric sensor array

Talanta ◽  
2010 ◽  
Vol 82 (4) ◽  
pp. 1292-1297 ◽  
Author(s):  
Mirjana Hruškar ◽  
Nikola Major ◽  
Marina Krpan ◽  
Nada Vahčić
Keyword(s):  
Simultaneous Determination ◽  
Sensor Array ◽  
Fermented Milk ◽  
Aroma Compounds ◽  
Potentiometric Sensor
Sign in / Sign up

Export Citation Format

Share Document