Nikolaos Zoumakis

Alexander Technological Educational Institute of Thessaloniki · General Department of Applied Sciences, Department of Food Technology

Series of experimental runs were carried out using a pilot scale spray drying unit to produce starch molecular inclusion complexes with fatty acids. Native normal maize and tapioca starch suspensions with added myristic or palmitic acid were employed at various concentrations and feed rates whereas the spray drier was operated at various drying air...

Nanocomposite films were prepared using normal maize starch, plasticized with glycerol and water and three different types of montmorillonite clay employing the solution method. A series of samples with different compositions were prepared by varying the concentrations of glycerol and nanoclay. The tensile properties of films were investigated as a...

This paper provides the performance evaluation of the meteorological component of The Air Pollution Model (TAPM), a nestable prognostic model, in predicting meteorological variables in urban areas, for both its surface layer and atmospheric boundary layer (ABL) turbulence parameterizations. The model was modified by incorporating four urban land su...

In their Article, Giovanni Forzieri and colleagues [1] provide plausible estimates of extreme weather-related risks for future European generations under a scenario of no adaptation. Another study [2] found that moderate temperatures cause most of the temperature-related mortality burden. People living in artificially cooled and heated environments...

A building’s energy consumption is dependent on its own design and construction and on its interaction with environmental parameters such as temperature, solar radiation, wind speed etc. Although these parameters are closely related to regional microclimate, they are also affected by the building and its surroundings and they should be taken into a...

A reliable estimation of the energy consumption of buildings including the short term prediction (1-4 days) of air conditioning loads, requires the use of trustworthy predictions of meteorological parameters such as temperature, solar radiation and vector rate at a very high spatial resolution i.e. hundreds of meters over the built-up areas. The us...

Angular-dependent polarized Raman spectroscopy was utilized to study nonpolar a-plane ( 1 1 ¯ 20 ) and semipolar s-plane ( 10 1 ¯ 1 ) InN epilayers. The intensity dependence of the Raman peaks assigned to the vibrational modes A1(TO), E1(TO), and E 2 h on the angle ψ that corresponds to rotation around the growth axis, is very well reproduced by us...

The pressure response of a polar wurtzite InxGa1-xN (x = 0.37) film epitaxially grown on a GaN/sapphire template was studied by means of combined Raman and photoluminescence (PL) mappings. The pressure slopes of the Raman peaks (partial derivative x/partial derivative P similar to 4.7 cm(-1).GPa(-1)) of the studied alloy are indicative of its inter...

In this study, the sensitivity of the Weather Research and Forecasting (WRF) model rainfall predictions to the choice of two commonly used boundary layer schemes, is examined through the simulation of an exceptionally heavy rainfall event over Chalkidiki peninsula in northern Greece. This major precipitation event, associated with a case of cycloge...

Heat stress-related mortality is one of the most commonly known and accepted health impacts of climate change in Greece, because of great political sensitivity following the major heat waves of 1987, 1988 and 2007 and the expected increase in frequency and intensity of extreme heat events in the near future. In the present study, an attempt was mad...

Climate change is projected to increase minimum, mean and maximum air temperatures and the frequency of very hot days, as heat waves become more frequent, intense and prolonged hot-weather episodes responsible for high excess morbidity and mortality rates. The present study examines the temporal fluctuations in heat wave occurrence and intensity in...

Raingauge data from four meteorological stations in Chalkidiki peninsula (Greece) were used to identify the characteristics of the synoptic circulation patterns associated with cold-season heavy rainfall events and corresponding flooding over the area. Precipitation climatology over the complex topography of Chalkidiki is characterized by limited a...

As climate changes, a direct effect of rising temperatures is an increase in the frequency and severity of extreme heat wave episodes. In the present study, an attempt was made to study the temporal fluctuations in heat wave occurrence and intensity and heat – related mortality, during the warm period (May, June, July, August and September) for the...

In this study, the Weather Research and Forecasting (WRF) model version 3.2 is used to examine the impact of precipitating ice and especially snow-graupel partitioning in the simulation of a heavy rainfall event over Chalkidiki peninsula in Northern Greece. This major precipitation event, associated with a case of cyclogenesis over the Aegean Sea,...

As a result of climate change, heat waves are expected to increase in severity and frequency. Taking into consideration the heavily stressed air quality conditions in the city of Thessaloniki, Greece, an attempt was made to study the temporal fluctuations in heat wave occurrence and intensity, during the summer period for the years 1970 – 2009. The...

A record breaking 24 h accumulated rainfall event was observed in Chalkidiki Peninsula, Greece on the 8th of October 2006. Intense precipitation was associated with strong low level convergence imposed by a low pressure system developed over the Aegean Sea and topographical lifting in the area of interest. Severe flooding and damage was reported es...

During the last years several attempts were made to introduce various air quality indices, defined for a specific air pollutant or a mixture of pollutants, based on standards and guidelines proposed by international organizations. In this work, air quality data (CO, SO2, O3, PM10 and NO2) corresponding to the six-year period between 2004 and 2009 a...

During the last years several attempts were made to introduce various air quality indices, defined for a specific air pollutant or a mixture of pollutants, based on standards and guidelines proposed by international organizations. In this work, air quality data (CO, SO2, O3, PM10 and NO2) corresponding to the six-year period between 2004 and 2009 a...

During the last years several attempts were made to introduce various air quality indices, defined for a specific air pollutant or a mixture of pollutants, based on standards and guidelines proposed by international organizations. In this work, air quality data (CO, SO2, O3, PM10 and NO2) corresponding to the six-year period between 2004 and 2009 a...

Since air pollution levels are strongly dependent on atmospheric conditions, it is important to take both into consideration when examining the effects of weather on human health. In this study, the discomfort conditions were estimated by using several air-quality stress indices based on air-pollutant concentrations in the center of Thessaloniki. A...

Taking into consideration the heavily stressed air quality conditions in the city of Thes-saloniki, Greece, an attempt was made to study the temporal fluctuations in heat wave occurrence and intensity during the summer period (June, July and August) for the years 1970–2005. The results demonstrate a continuous warming trend as well as the increase...

Heat stress-related mortality is among main impacts of climatic extremes on human society. An extreme heat wave can be catastrophic or not depending on its intensity, extent and duration, but also on the population adaptation to the local climate and the awareness of the public authorities. Excess monthly mortality was established, for total and ca...

As a result of climate change, heat waves are expected to increase in severity and frequency. Hot weather extremes appear to have a profound effect on human health and well-being. In addition, humidity affects human comfort, and the perceived temperature by humans is largely dependent on atmospheric moisture content. The danger posed by the combine...

In the present study, an attempt was made to give a preliminary estimate of heat-related mortality in northern Greece, during the summer period, for the years 1970–2009, with special regard to extreme heat waves. Long-term trends in the human mortality data, for the hot period of the year, can be influenced by different demographic factors (change...

A CFD dispersion model is presented to predict the local effect of heavily travelled roads on air pollution concentrations measured at certain monitoring stations in the commercial center of Thessaloniki. The model used in this study is a three dimensional CFD model with the shearstress transport k-ω turbulence scheme. The complex topography of the...

The present study refers to experimental ambient air hydrocarbon measurements in the city of Thessaloniki, Greece, from May to July 2006. The measurements are performed at two sites of the Municipal Air Quality Network of Thessaloniki, at the commercial city center (11.4 m asl) and at an urban peripheral site (174.0 m asl). The two locations, city...

A theoretical investigation is presented on the approximate solutions of the radiation budget equation in complex terrain. A method of calculating an exact solution to the net radiation balance is also developed and compared to the commonly used approximations. The suggested procedure adopts the effects of multiple reflections of the longwave radia...

Air pollution in a modern city has become a serious environmental problem, because of the combined effects of various pollutants on the physical and mental health of citizens, and, in general, the quality of urban life. Among the sources of pollution, the car traffic is of main importance, in particular, the presence alone of moving and stationary...

In this study, quasicontinuous measurements of major aromatic volatile organic compounds (VOCs), which include benzene, toluene, ethylbenzene, and xylenes were carried out by means of an automatic gas chromatograph (GC-PID analyzer), in the urban air of Thessaloniki, at a mean level of 27 m above ground, during the years 2003 and 2004. The highest...

The factors that affect the atmospheric energy budget approach used in the thermodynamic valley inversion destruction model of Whiteman and McKee are investigated theoretically. The height at which the sinking inversion top meets the rising convective boundary layer to destroy valley inversions can be uniquely determined by the topographic characte...

A simple thermodynamic parameterization based on a modified version of the Whiteman and McKee inversion destruction model is presented to simulate the evolution of vertical temperature structure during the inversion breakup period in idealized valleys under clear, undisturbed weather conditions. The proposed method adopts simplified semiempirical p...

Past fuel energy crises and current high crude oil prices have forced the scientists to investigate the use of renewable fuels, thus succeeding in reducing the world's dependence on fuels derived from petroleum products. Plant oils and their derivatives have been studied for their use as renewable fuels, but their impact upon the engine performance...

This study reports systematic ambient PM2.5 measurements during 2004-2005, for the first time in urban Thessaloniki area. PM10 concentrations have been also measured in Thessaloniki from 1989 until today. The measurements are performed at a central site, in the Thessaloniki area, using tapered element oscillating microbalance (TEOM) and beta-absorp...

In this study, the synoptic scale atmospheric circulation prevailing during 1989-2004 air pollution episodes in the greater area of Thessaloniki (GTA) was examined. The episodes are defined on the basis of the main pollutants measured (SO2, PM10, black smoke, CO, NO2 and O 3) on an hourly basis, at five monitoring stations of the Municipal Air Qual...

In this study a simple semi-empirical scheme is presented which gives estimates of net all-wave radiation and surface sensible, latent and ground heat fluxes from routine weather data during daytime in complex terrain. The suggested methodology is based on the following fundamental assumptions: The radiation balance is primarily driven by incoming...

This study reports systematic ambient PM10 measurements at the Municipal Air Quality Network of Thessaloniki, from 1989 to 2000. PM10 concentrations were measured by two different methods, the beta-gauge principle and the tapered element oscillating microbalance method. The correlation between the two daily PM10 concentrations (derived from the abo...

A numerical model based on a multidimensional minimization algorithm was developed to estimate the aerodynamic characteristics of forest and tall vegetation canopies. The suggested methodology should be especially useful for many applications in the field of biotic and abiotic systems, air pollution modeling, and agricultural and forest micrometeor...

Data obtained with a Brewer spectrophotometer are used to calculate the total columnar amount of sulphur dioxide concentrations over the industrial area of Thessaloniki, in Northern Greece. Using a two-dimensional numerical diffusion box model estimates of the effective mixing height of the polluted layer, the mean residence time and average vertic...

In this study continuous concentration measurements of atmospheric pollutants for a 3 year period are analyzed. These measurements have been carried out in the central area of Kozani (down town Kozani), the largest city of West Macedonia, a region in Northern Greece. Specifically, the yearly, monthly, weekly and diurnal variation in concentrations...

The rural population in Northern Greece, representing 30% of the total rural population in the country, is exposed to significant doses of radiation due to the existence of natural radionuclides in soil. The present work is a survey of the levels of activity concentrations of 226Ra, 232Th and 40K in the soils of a 42755 km2 geographical area inside...

The aim of the present study is to analyze sulphur dioxide and suspended particle concen¬trations in the urban area of Thessaloniki, The air pollution data span over a period of almost ten years, from 1989 to 1997. By combining the diurnal and seasonal variability and spatial distribution of these pollutants we provide useful informations of the ai...

The aim of the present study is to analyze sulphur dioxide and suspended particle concen¬trations in the urban area of Thessaloniki, The air pollution data span over a period of almost ten years, from 1989 to 1997. By combining the diurnal and seasonal variability and spatial distribution of these pollutants we provide useful informations of the ai...

A computer optimization quasi-Newton numerical solution technique is applied to determine the. hypothetical worst-case meteorology that causes a maximum calculated concentration, which is related to the air pollution episode concentrations, and to locate the receptor where the critical concentration occurs, in air quality dispersion prediction for...

"ENVIRO-SOFT" is a network computer system that gives information daily and annually, about atmospheric pollution. The connection and updating are taking place through telephone lines. a data base software was developed containing the atmospheric pollutants, the measurement sources and areas displays graphs about these dedicated pollutants. A rose-...

A simple quasi-Newton numerical scheme is applied to determine the hypothetical worst-case meteorology that will result in the maximum combined concentrations at any receptor location in air quality modeling over short distances for multiple point sources. Also, a search procedure is suggested to investigate the combination of location and atmosphe...

The main purpose of this study is to analyse the diurnal variability of air pollutants (e.g., carbon monoxide, sulphur dioxide, nitric oxide, nitrogen dioxide, ozone and smoke) using different fitted probability density functions and establish the relationship between emissions standards and street-canyon air quality levels in the commercial center...

In this paper an analysis of SO2, NO, NO2, O3, smoke and CO concentration levels, measured by a monitoring network in Thessaloniki area from 1989 to 1993, is attempted. The seasonal variability and long-term trends in air quality and their causes are discussed. The observed significant decreasing trends in SO2 and smoke concentrations are due to th...

Recent observations of air pollutant concentrations measured within and above street canyons were used to study the average vertical profiles of vehicular pollutant concentrations in the urban environment. The idea of an exponential vertical concentration distribution, exp( −Bzq), resulted from a near ground-level source diffusing over flat terrain...

Semi-empirical and theoretical formulations which have been proposed to describe the transition-layer mean wind-speed profiles (Zoumakis, 1992c; 1993c; 1993d; 1994) are used to derive relationships between the roughness length zo, zero-plane displacement d, and transition-layer depth z*, and to estimate the diffusivity coefficients K of turbulence...

The purpose of this study is to analyse the diurnal variability of CO concentration observations using different fitted statistical distributions. A simple microscale dispersion model was also used to predict the local effect of heavily-travelled roads on carbon monoxide concentrations measured at certain monitoring stations in the Thessaloniki bas...

A semianalytical method based on a mass conservation principle is presented for describing the transition- layer profiles of mean wind speed and momentum diffusivity and for estimating the aerodynamic characteristics of forest and tall vegetation canopies. This method incorporates density and vertical structure of the canopy and assumes that the tr...

The effect of artificially added I-131 on lactic acid bacteria (LAB) in cheese butter and their by-products, cheese whey and buttermilk, was studied. The radioisotope was introduced directly to cow milk and cream in doses equivalent to 10,000 Bq/Kg. After homogenization and cooling, milk and cream were inoculated with 1.5% mixed activated cultures...

Feta the most common cheese in Greece, was produced from sheep milk by a procedure normally used in Greece. The effect of artificially added I-131 on the ripening of feta cheese was studied. The contamination was introduced directly to milk (25 KBq/Kg milk). The rate of ripening was evaluated up to two months by determining the pH, moisture, fat, t...

Using the logarithmic wind profile under stable stratification, a classification scheme was obtained for the Monin-Obukhov stability length and for the wind profile power law exponent in terms of the surface roughness length and the PasquillD-G stability classes, anywhere in the surface layer.

The properties of the Gaussian plume equation have led many industrial designers to plan their stack system so that ambient pollutant concentrations are reduced to levels considered safe from the standpoint of undesirable effects. This paper demonstrates the characteristics of worst‐case maximum air concentrations due to an elevated point source di...

Solar Ultraviolet spectrophotometric measurements are used to provide estimates of the total columnar sulphur dioxide concentrations over urban, semirural and industrial areas of Thessaloniki in Northern Greece. The systematic observations of the SO2 column represent an estimate of the impact of anthropogenic sulphur dioxide on the solar radiation...

A simple method based on a mass-conservation principle is presented for estimating the aerodynamic characteristics of forest and tall vegetation canopies. The method uses semi-empirical modifications of the profiles in the transition layer, eliminating the need for measured wind data extending into the logarithmic regime. Also, various schemes are...

Nomograms were constructed to determine relations among different stability parameters in the surface layer. The variables interrelated were the Monin-Obukhov stability parameter, ξ=z/L, the bulk Richardson number, Rib, and the PasquillA-F stability classes. Also, the nomograms were used to estimate the Monin-Obukhov length variation, with respect...

The dependence of the wind profile power-law exponent (p) on surface roughness and atmospheric stability is depicted assuming a height variation of p (Huang, 1979; Hanafusa et al., 1986) and using the formulation of Zilitinkevich (1989) for determining the velocity profiles in a neutrally and stably stratified planetary boundary layer. The theoreti...

Summary Semi-empirical formulations which have been proposed to describe the wind and potential temperature profiles are used to derive relationships between the gradient Richardson number, Ri, the finite-difference layer Richardson number, Rib, the surface layer Richardson number, Ris, and the bulk Richardson number,B, through the atmospheric surf...

The aim of the present study is to analyse emissions of SO2, NO2, particulates and radionuclides from the lignite fired power stations in the Ptolemais-Kozani valley in the northern part of Greece. A thermodynamic model is proposed to calculate ground-level concentrations under inversion break-up fumigations.

The present work deals with the diffuse radioactivity measurements for the period of last two years (1989 - 1990) in the industrial area of Thessaloniki (Sindos). Gamma- ray spectroscopy was used to indentify the existance of 214Pb, 133Ba, 85Sr, or85Kr, 103Ru and 40K in the atmosphere of Sindos; three years after the Chernobyl accident. A mathemati...

A dynamic grid-based numerical model and a simple microscale dispersion model (based on the physical principle of mass conservation) were used to predict the local effect of heavily travelled roads on CO-concentrations measured at nearby monitoring stations in the Athens and Thessaloniki basin.

An experiment was conducted in fresh - water fish, ( A. anguilla) cultured, in large water tanks artificially contaminated with radioactive 137Cs (3000 Bq / 1) to determine the uptake of 137Cs and its physiological and histological effects in different fish organs.

Yoghurt, a cultured milk product, routinely consumed in Greece, was prepared from cow milk and sheep milk by a procedure normally used in Greece. The behavior of artificially added 131I on lactic acid microflora was studied. The lactic acid bacteria (LAB) counts decreased by 45% in the "set style" or "Strained style" yoghurt due to the presence of...

The present study proposes that instead of using a measured velocity profile, semi-empirical wind profiles may be used to estimate the aerodynamic characteristics of forest and tall vegetation canopies. The suggested methodology should be especially useful for many applications in the field of biotic and abiotic systems and air pollution meteorolog...

Observations of total columnar amount of SO2, O-3, NO2 and stratospheric NO2 column have been made with the Brewer spectrophotometer #036, in the industrial area of Thessaloniki (40.5 degrees N, 20.9 degrees E), in Northern Greece. The diurnal and seasonal variations of these pollutants and their causes are discussed and compared with measurements...

A three-dimensional numerical model for predicting the time-dependent dynamic behavior of chemically reacting air pollutants in the Athens basin is developed. The model is used to estimate the spatial and temporal distribution of CO, SO2, NO, NO2 and O-3 emissions in Athens. The model results were also validated and compared with actual measurement...

An approximate relationship between the gradient, Ri, and the bulk Richardson number, Rib, for unstable atmospheric conditions, is suggested. The proposed relation shows much better agreement with the estimation provided by a numerical iterative method than the usual approximations suggested by Louis and Byun.

Characteristics of air pollution episode concentrations from an elevated continuous point source are derived from the Gaussian plume equation. The critical wind speed, critical plume rise and downwind distance are also obtained. The suggested methodology should be especially useful for determining compliance with air pollution episode criteria and...

A three-dimensional, grid-based numerical air pollution model for the estimation of the mean ground and total concentrations of SO2 in the Thessaloniki area is developed. Based on the continuity equation, the modeling system incorporates the combined influences of advective transport, turbulent diffusion and source emissions. The urban sources of S...

Semiempirical formulations which have been proposed to describe the surface layer wind and potential temperature profiles, were used to derive relationships between the wind profile power-law exponent, p, the Monin-Obukhov scaling length, L, and the surface roughness parameter, z0. Nomograms were constructed for ξ=z/L, as a function of ξ0=z0/L and...

Relationships between the bulk Richardson number, B, and other stability parameters were derived for the atmospheric surface layer. Nomograms were constructed, relating the Monin-Obukhov stability parameter, z/L, to B. The nomograms and the graph of Golder (1972) were used to establish various schemes for classifying z/L, B and Ri, in terms of the...

Semi-empirical formulae, which have been proposed to estimate the Monin-Obukhov lengthL, are used to derive equations predicting the surface roughness lengthz 0 and the potential temperature θ0 at heightz 0, using routine meteorological measurements. The friction velocityu * is obtained from the computed values ofL andz 0.

The purpose of this work is to relate the results and the conclusions which arose from the operation of nuclear plants from many years and from the application various radioecological models which describe the diffusing and the burdening of ecological system with radioactive substances in relation to the general problem of the pollution of the envi...

The variation of the wind profile power-law exponent (p) with respect to changes in atmospheric stability is depicted using the formulation of Ku et al. (1987) for specifying the Monin-Obukhov scaling length (L) under stable atmospheric conditions. The theoretical estimates for the bulk approximation of p as a function of L under stable conditions...

This work presents the climatology of the sulphur dioxide column over Thessaloniki derived from three years of observation with the Brewer spectrophotometer. The SO2 column averages 2.5 m atm‐cm and the shielding of UV‐B by SO2 is investigated and compared with the changes in shielding resulting from an anticipated ozone reduction. Columnar and sur...

Measurements of S02 column at Thessaloniki (41°N) show a minimum in the late spring of 1983, approximately three months after the occurence of the maximum of the El Chichon aerosol in the stratosphere at these latitudes. It is suggested that the injection of the aerosol into the upper troposphere provides a scavenging mechanism for S02 and other tr...