Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 123Citation - Scopus: 134Effect of Moisture on Adsorption Isotherms and Adsorption Capacities of Co2 on Coals(American Chemical Society, 2009) Özdemir, Ekrem; Schroeder, KarlThe effect of moisture on the adsorption isotherms and adsorption capacities of CO 2 on Argonne Premium coals has been investigated. In some experiments a small hysteresis was observed between the adsorption and desorption isotherms. The hysteresis was absent or negligible for high-rank and as-received coals but was discernible for lower rank and dried coals. An equation that accounted for the volumetric changes when an adsorbate alters the structure of an adsorbent was employed to interpret the data. The best-fit solutions indicate that the coal volume decreases upon drying. The microscopic shrinkage estimated using helium expansion was greater than the shrinkage reported using the bed-height technique. The microscopic shrinkage was 5-10% for low-moisture medium and high-rank coals and up to 40% for low-rank coals having higher moisture contents. The CO 2 swelling of coals during adsorption isotherm measurements was estimated to be about the same as the shrinkage that occurred during the moisture loss. The adsorption capacity, isosteric heat of adsorption, average pore size, and surface area of the as-received (moist) and dried Argonne coals were estimated after accounting for the volume changes. The isosteric heat of adsorption of CO 2 was found to be between 23 and 25 kJ/mol for as-received coals and between 25 and 27 kJ/mol for dried coals, regardless of the rank. The degree of drying was shown to affect the adsorption capacity and the calculated surface area. For dried coals, the adsorption capacity showed the typical 'U-shape' dependence on rank whereas the as-received coals displayed a more linear dependence. A relationship is proposed to quantify the effect of moisture on the adsorption capacity. The mechanism of CO 2 adsorption on moist coals and the implications of the lower adsorption capacity of wet coals to coal seam sequestration of CO 2 are presented.Article Citation - WoS: 7Citation - Scopus: 7Dampness Problems in a Historic House in Izmir, Turkey(Taylor and Francis Ltd., 2009) Yardım, Bülent; Tunçoku, Selim SarpThe study, as a preliminary stage of the restoration work of a historic house from Levantine ages of Izmir in the nineteenth century, involves the examination of the dampness basement problems. Moisture contents and temperature of the wall surfaces were monitored by non-destructive techniques, such as direct measurements of electrical conductivity and infrared thermography. The results were evaluated in the light of physical properties, moisture, and soluble salt types and contents in the materials, outdoor, and indoor climatic conditions, layout of the site, and architectural features of the building. In addition to rising damp and lack of sufficient ventilation for years, some faulty details along the intersections with the terraces of the neighbor buildings, and intersection with the asphalt coated street and the basement windows that gave way for rainwater leaks were the other sources of dampness. Some cool but relatively dry parts of the walls were found to be potential zones for dampness problem through condensation between midnight and early mornings, especially in winter.Article Citation - WoS: 9Citation - Scopus: 10Methods of Humidity Determination Part Ii: Determination of Material Humidity(Springer Verlag, 2008) Rübner, Katrin; Balköse, Devrim; Robens, E.Part II covers the most common methods of measuring the humidity of solid material. State of water near solid surfaces, gravimetric measurement of material humidity, measurement of water sorption isotherms, chemical methods for determination of water content, measurement of material humidity via the gas phase, standardisation, cosmonautical observations are reviewed.Article Citation - WoS: 8Citation - Scopus: 8Genetic Multivariate Calibration for Near Infrared Spectroscopic Determination of Protein, Moisture, Dry Mass, Hardness and Other Residues of Wheat(John Wiley and Sons Inc., 2006) Özdemir, DurmuşDetermination of wheat flour quality parameters, such as protein, moisture, dry mass by wet chemistry analyses takes long time. Near infrared spectroscopy (NIR) coupled with multivariate calibration offers a fast and nondestructive alternative to obtain reliable results. However, due to the complexity of the spectra obtained from NIR, some wavelength selection is generally required to improve the predictive ability of multivariate calibration methods. In this study, two different wheat data sets are investigated with the aim of establishing successful calibration models using NIR spectra of wheat samples. The first data set (material 1) was obtained from the ftp address (ftp://ftp.clarkson.edu/pub/hopkepk/Chemdata/) and contained 100 NIR spectra of wheat of which wet chemical analysis of protein and moisture content were done with reference methods. The second data set (material 2) contained 176 spectra and was downloaded from http://www.spectroscopynow.com/Spy/basehtml/SpyH/1,1181, 2-1-2-0-0-newsdetail-0-74,00.html. This wheat data set was given with the quality parameters, such as protein content, moisture content, other residues, dry mass, protein content in dry mass and hardness that were determined previously. Multivariate calibration models generated with genetic inverse least squares method demonstrated very good prediction results for the parameter mentioned here. Overall, the average per cent recoveries (APR) ranged between 99.23% and 100.34% with a standard deviation (SD) ranging from 0.34 to 3.15 for all the parameters investigated, except hardness. The APR value of hardness was 103.32 with the SD of 14.97.