Henryk Sobczuk

Determination of Moisture Diffusivity using the Time Domain Reflectometry (TDR) Method

The time domain reflectometry (TDR) method is commonly used for the measurement of moisture content in soil science. In this study, the method is employed for the measurement of moisture profiles in building materials. The practical applications of the method are presented on an example of water penetration into cellular concrete (aerated autoclaved concrete) samples. The measured results are then used for the determination of moisture diffusivity as a function of moisture content.

Application of Gas Sensor Arrays in Assessment of Wastewater Purification Effects

A gas sensor array consisting of eight metal oxide semiconductor (MOS) type gas sensors was evaluated for its ability for assessment of the selected wastewater parameters. Municipal wastewater was collected in a wastewater treatment plant (WWTP) in a primary sedimentation tank and was treated in a laboratory-scale sequential batch reactor (SBR). A comparison of the gas sensor array (electronic nose) response to the standard physical-chemical parameters of treated wastewater was performed. To analyze the measurement results, artificial neural networks were used. E-nose—gas sensors array and artificial neural networks proved to be a suitable method for the monitoring of treated wastewater quality. Neural networks used for data validation showed high correlation between the electronic nose readouts and: (I) chemical oxygen demand (COD) (r = 0.988); (II) total suspended solids (TSS) (r = 0.938); (III) turbidity (r = 0.940); (IV) pH (r = 0.554); (V) nitrogen compounds: N-NO3 (r = 0.958), N-NO2 (r = 0.869) and N-NH3 (r = 0.978); (VI) and volatile organic compounds (VOC) (r = 0.987). Good correlation of the abovementioned parameters are observed under stable treatment conditions in a laboratory batch reactor.

Evaluating Soil Moisture Status Using an e-Nose

The possibility of distinguishing different soil moisture levels by electronic nose (e-nose) was studied. Ten arable soils of various types were investigated. The measurements were performed for air-dry (AD) soils stored for one year, then moistened to field water capacity and finally dried within a period of 180 days. The volatile fingerprints changed during the course of drying. At the end of the drying cycle, the fingerprints were similar to those of the initial AD soils. Principal component analysis (PCA) and artificial neural network (ANN) analysis showed that e-nose results can be used to distinguish soil moisture. It was also shown that different soils can give different e-nose signals at the same moistures.

Community Composition and Abundance of Protozoa Under Different Concentration Of Nitrogen Compounds at “Hajdow” Wastewater Treatment Plant / Zbiorowiska Pierwotniaków I Ich Liczebność W Oczyszczalni Ścieków „Hajdów” Przy Różnych Stężeniach Związków Azotu

Abstract The protists notably ciliates and testate amoebas in the conditions of modernized wastewater treatment plants “Hajdow” (Lublin, Poland) and the nitrogen removal efficiency were studied. Sampling took place every week during the period of August-September 2010. The total of 31 taxa of ciliates and 3 taxa of testate amoebas were identified. Most of the species were registered during the whole research period. Significant abundance reached the following species: Acineria uncinata, Aspidisca cicada, Aspidisca lynceus, Vorticella aquadulcis, Vorticella infusionum, Arcella vulgaris, Euglypha acanthophora and Pyxidicula operculata. In September increase in efficiency of nitrogen removal process was registered. The research shows that the increase of nitrogen reduction efficiency was accompanied by increase of ciliates quantity, mainly due to peritrichid ciliates. Abstrakt Przedstawiono analizę zgrupowań pierwotniaków obejmującą orzęski oraz ameby skorupkowe, zasiedlające kolejne urządzenia głównego ciągu technologicznego oczyszczalni ścieków „Hajdów” na tle zmian w stężeniach związków azotu. Badania prowadzono po modernizacji części biologicznej realizowanej w celu podniesienia skuteczności usuwania ze ścieków związków biogennych, a w szczególności związków azotu. Pobór próbek prowadzony był raz w tygodniu w okresie sierpień-wrzesień 2010 roku. W badanym materiale biologicznym wyodrębniono 31 gatunków orzęsków oraz 3 gatunki ameb skorupkowych. Większość ze wspomnianych gatunków pierwotniaków odnotowywana była przez cały okres badań. Najbardziej licznie w analizowanym materiale biologicznym reprezentowane były następujące gatunki: Acineria uncinata, Aspidiscacicada, Aspidisca lynceus, Vorticella aquadulcis, Vorticella infusionum, Arcella vulgaris, Euglyphaacanthophora i Pyxidicula operculata. We wrześniu odnotowany został wzrost skuteczności procesu usuwania związków azotu. Prezentowane badania wskazują, iż wzrostowi stopnia usuwania ze ścieków związków azotu towarzyszył wzrost ilości orzęsków odnoszący się głównie do form peritricha.

Estimation of building material moisture using non-invasive TDR sensors

The article presents the noninvasive attempt to measure moisture of building materials with the use of electric methods. Comparing to the other techniques of moisture detection like chemical or physical, the electric methods enable quick moisture estimation and they seem to be a suitable solution to monitor moisture changes. Most of electric moisture meters are the capacitance and resistance sensors. A perspective technique to determine moisture of building materials and barriers is Time Domain Reflectometry (TDR) method. This method has been successfully applied for moisture determination of the soils and since a few years has been used to measure moisture of building materials. The attempts to measure moisture of building materials require modification of traditional TDR sensor construction and extra calibration procedures. Sensors applied for building materials, comparing to the traditional ones are noninvasive. The advantages of surface sensors proposed in this article are the following: no influence ...

Estimation of water absorption coefficient using the TDR method

Moisture accumulation and transport in the building barriers is an important feature that influences building performance, causing serious exploitation problems as increased energy use, mold and bacteria growth, decrease of indoor air parameters that may lead to sick building syndrome (SBS). One of the parameters that is used to describe moisture characteristic of the material is water absorption coefficient being the measure of capillary behavior of the material as a function of time and the surface area of the specimen. As usual it is determined using gravimetric methods according to EN 1925:1999 standard. In this article we demonstrate the possibility of determination of water absorption coefficient of autoclaved aerated concrete (AAC) using the Time Domain Reflectometry (TDR) method. TDR is an electric technique that had been adopted from soil science and can be successfully used for real-time monitoring of moisture transport in building materials and envelopes. Data achieved using TDR readouts show h...

Assessment of batch bioreactor odour nuisance using an e-nose

AbstractThe method of assessing a smell nuisance of the SBR laboratory bioreactor using a calibrated gas sensor array (e-nose) is described in the article. The SBR bioreactor is used to remove organic carbon and nutrients and can contribute to the emission of smell nuisance compounds. Two measurement devices were used as an information source regarding the presence of smell nuisance gases: an array consisting of 8 MOS-type gas sensors and a dynamic olfactometer. The research covered the stage of a normal bioreactor performance and simulation of the aeration system failure. With the gas sensor array, a static response has been recorded for air samples above the surface of treated wastewater. The dynamic olfactometer Ecoma TO-7 was simultaneously used in order to measure odour concentration with the “yes–no” method, according to EN-13725:2007. Comparative analyses were carried out with artificial neural networks in the statistical program. The research conducted indicates that normal bioreactor performance ...

Classification of buildings mold threat using electronic nose

Mold is considered to be one of the most important features of Sick Building Syndrome and is an important problem in current building industry. In many cases it is caused by the rising moisture of building envelopes surface and exaggerated humidity of indoor air. Concerning historical buildings it is mostly caused by outdated raising techniques among that is absence of horizontal isolation against moisture and hygroscopic materials applied for construction. Recent buildings also suffer problem of mold risk which is caused in many cases by hermetization leading to improper performance of gravitational ventilation systems that make suitable conditions for mold development. Basing on our research there is proposed a method of buildings mold threat classification using electronic nose, based on a gas sensors array which consists of MOS sensors (metal oxide semiconductor). Used device is frequently applied for air quality assessment in environmental engineering branches. Presented results show the interpretation of e-nose readouts of indoor air sampled in rooms threatened with mold development in comparison with clean reference rooms and synthetic air. Obtained multivariate data were processed, visualized and classified using a PCA (Principal Component Analysis) and ANN (Artificial Neural Network) methods. Described investigation confirmed that electronic nose – gas sensors array supported with data processing enables to classify air samples taken from different rooms affected with mold.Mold is considered to be one of the most important features of Sick Building Syndrome and is an important problem in current building industry. In many cases it is caused by the rising moisture of building envelopes surface and exaggerated humidity of indoor air. Concerning historical buildings it is mostly caused by outdated raising techniques among that is absence of horizontal isolation against moisture and hygroscopic materials applied for construction. Recent buildings also suffer problem of mold risk which is caused in many cases by hermetization leading to improper performance of gravitational ventilation systems that make suitable conditions for mold development. Basing on our research there is proposed a method of buildings mold threat classification using electronic nose, based on a gas sensors array which consists of MOS sensors (metal oxide semiconductor). Used device is frequently applied for air quality assessment in environmental engineering branches. Presented results show the interpretati...

Time Domain Reflectometry

Originally, the TDR measurement technique was developed to detect defects in telecommunication cables and electrical wires, Moffitt (1964). Within recent decades, TDR was also applied to determine and monitor volumetric moisture contents in particulate and porous media, in particular soil but lately also building materials such as building bricks, concrete, sandstone, etc., see e.g. Dobson et al. (1985), Topp et al. (1980), and Phillipson et al. (2008). TDR is in general based on the measurement of the propagation time of an electromagnetic signal along a wave guide also referred to as probe, usually there and back. In the low frequency range, i.e. <10 GHz, water possesses a considerably higher relative permittivity (e w ≈ 80) than mineral compounds (e s ≈ 4) or air (e a ≈ 1). From the measurement of the propagation time of an electromagnetic signal along a wave-guide, the mean relative permittivity, which is among others moisture dependent, of the investigated dielectric material is derived from the reflection picture. Subsequently, the volumetric water content can be determined directly from the mean relative permittivity applying suitable material functions, which relate mean relative permittivity and volumetric moisture content.

Comparison of interpretation methods of thermocouple psychrometer readouts

Thermocouple psychrometers allow to determine the water potential, which can be easily recalculated into relative humidity of air in cavity of porous materials. The available typical measuring range of probe is very narrow. The lower limit of water potential measurements is about −200 kPa. On the other hand, the upper limit is approximately equal to −7000 kPa and depends on many factors. These paper presents a comparison of two interpretation methods of thermocouple microvolt output regarding: i) amplitude of voltage during wet-bulb temperature depression, ii) field under microvolt output curve. Previous results of experiments indicate that there is a robust correlation between water potential and field under microvolt output curve. In order to obtain correct results of water potential, each probe should be calibrated. The range of NaCl salt solutions with molality from 0.75M to 2.25M was used for calibration, which enable to obtain the osmotic potential from −3377 kPa to −10865 kPa. During measurements w...