Formation of viable noncultural state of <Emphasis Type="Italic">Candida Albicans</Emphasis>

The paper has investigated the influence of NaOCl on the cells of Candida albicas with the aim of finding viable noncultural state and also conditions of their rehabilitation. Microscopic research of the cells Candida albicans has been given in the indicated state colored with trypan blue.     

Detection of Microorganisms in Nonculturable State in Chlorinated Water

The nonculturable state in sanitary demonstrative microorganisms Escherichia coli and Candida albicans caused by the chlorine disinfection of water has been studied. The technique developed for detecting such microorganisms is assumed as a basis of the State Standard of Ukraine “Quality of water. Detection of microorganisms in nonculturable state in water”.     

Bioaugmentation of a sequencing batch reactor with <Emphasis Type="Italic">Archaea</Emphasis> for the treatment of reject water

In this study, the bioaugmentation of a sequencing batch reactor (SBR) for the treatment of reject water from wastewater treatment plant was evaluated. For the bioaugmentation step a product containing an enrichment of microorganisms from the Archaea domain was used to enhance the performance of the reactor for treating reject water. The experiment was carried out in two parallel lab-scale sequencing batch reactors. The first one (SBR A) was bioaugmented with a suspension of microorganisms from the Archaea domain, while the second reactor (SBR B) was not bioaugmented. The results here presented show that the SBR technology could sustain efficient NH ₄ ⁺ –N and chemical oxyden demand removal rates and can be applied for the treatment of reject water. Moreover, the addition of microorganisms belonging to the Archaea domain improved the SBR overall operation, especially when the loading in the influent was increased. Administering Archaea to the reactor had also a positive effect on ammonia oxidation as well as on the nitrite removal.     

Impact of different frequencies in the entrapment of bacterial pathogens from drinking water using dielectrophoretic phenomena

The article has investigated the removal of water borne pathogens using dielectrophoresis (DEP) filter which is energized by varying the frequency of the applied potential from 10 kHz to 2 MHz with different voltage levels of 5; 10; 15 and 20 V. Separate experiments are conducted in artificially contaminated water samples with Escherichia coli, Staphylococcus aureus and Vibrio cholerae up to 2 h. The impact of signal frequency and voltages on DEP based water treatment system has been analyzed statistically. Results have demonstrated that an AC signal of 20 V with frequency range of 500 kHz to 2 MHz is suitable to remove the tested bacterial population and the rate of removal of E. coli is the highest with a dielectrophoretic filtration efficiency of 77.1%.     

Optimal recultivation conditions of <Emphasis Type="Italic">Candida Albicans</Emphasis> staying in non-culturable state

Optimal conditions for recultivation of Candida albicans staying in viable but non-culturable state have been established. The effect of sodium hypochlorite on the transition of this culture into non-culturable state was investigated. The conditions of the culture reactivation were determined. These conditions include the effect of M-9 nutrient medium components and the cultivation temperature on recultivation process.     

The Simultaneous Bioremoval of Cr(III) and Dye by Immobilized <Emphasis Type="Italic">Phanerochaete Chrysosporium</Emphasis>

To attain better removal efficiency and higher toxic resistance, the alginate was used to immobilize Phanerochaete chrysosporium BKM-F-1767 in this study. And according to the characteristics of tannery wastewater, inhibitory effect of Cr(III) to the decolorization was investigated and adsorption kinetics of Cr(III) by the immobilized P. chrysosporium had been established. Furthermore, the Acid Violet 7 and Basic Fuchsin contributed as the experimental dyes in the paper, the removal studies were performed at an initial pH of 4.5. The combined effects of Cr and dyes on the simultaneous removal properties were determined in a batch system at different levels of Cr and dyes. Moreover, the dose-response relationship and a kinetic equation describing the simultaneous removal properties had been established. The results have proved that the immobilized P. chrysosporium has the ability to treat the tannery wastewater.     

Features of disinfection kinetics of water containing <Emphasis Type="Italic">Escherichia Coli</Emphasis> in conditions of hydrodynamic cavitation

The paper has investigated the disinfecting effect of hydrodynamic cavitation on the microorganisms of E. coli in water. It has been found that disinfection kinetics depend on the intensity of the hydrodynamic cavitation field, the microbial load, and gas content. We have studied structure and morphology variation of the E. coli bacteria. It has been demonstrated that the antimicrobial effect is achieved owing to the physicochemical effects of the cavitation field, under whose influence there occurs mechanical destruction of cells and chemical disinfection by the radicals of hydroxyl and hydrogen peroxide.     

A Method to Assess the Accuracy of Pseudo-Random Number Sampling Methods from Evacuation Datasets

We propose a method for assessing the accuracy of pseudo-random number sampling methods for evacuation modelling purposes. It consists of a systematic comparison between experimental and generated distributions. The calculated weighted relative error (E _{w_rel} ) is based on the statistical parameters as central moments (mean, standard deviation, skewness and kurtosis) to shape the distribution. The case study involves the Box–Muller transform, the Kernel-Epanechnikov, the Kernel-Gaussian and the Piecewise linear generating samples from eight evacuation datasets fitted against normal, lognormal and uniform distributions. Keeping in mind that the Bos Muller method has two potential sources of error (i.e. distribution fitting and sampling), this method produces plausible results when generating samples from the three types of distributions (E _{w_rel}  < 0.30 for normal, lognormal and uniform distributions). We also fund that the Kernel Gaussian and the Kernel Epanechnikov methods are well accurate in generating samples from normal distributions (E _{w_rel}  < 0.1) but potentially inaccurate when generating samples from uniform and lognormal distributions (E _{w_rel}  > 0.80). Results suggest that the Piecewise linear is the most accurate method (E _{w_rel}  = 0.01 normal; E _{w_rel}  = 0.04 lognormal; E _{w_rel}  = 0.009 uniform). This method has the advantage of sampling directly from empirical datasets i.e. no previous distribution fitting is needed. While the proposed method is used here for evacuation modelling, it can be extended to other fire safety engineering applications.     

Variation of total toxicity of cationic SAS solutions in ozonization,UV radiation,and O<Subscript>3</Subscript>/UV treatment

Variation of total toxicity of cationic SAS (surface-active substance) solutions in ozonization, UV radiation, and O₃/UV treatment was evaluated by the change of bioluminescence intensity of the bacteria Vibrio fisheri B 7070 or Photobacterium phosphoreum B 7071 and chemiluminescence intensity in a reaction of luminole with H₂O₂ caused by exometabolites Daphnia magna. It has been shown that the least toxicity is characteristic of reaction blends after O₂/UV treatment of cationic SAS solutions.     

Effects of geometry on the sound field in atria

The atria in commercial buildings are widespread. However, the sound environment has not been given sufficient consideration. Geometry affects the acoustics in the atria. The concept of geometry in this paper includes five parameters, namely, length (l), height (h), aspect ratio of length to width (l/w), skylight form and slope, to provide suggestions for the acoustic environment design in atria. A series of computer models are simulated to analyse the effects of the form parameters on the acoustic environment, such as sound pressure level (SPL) and reverberation time (T₃₀ in this paper). The results indicate that with an increase in the length or height, the values of the average SPL decrease, and the trends of the curves are logarithmic. For an increasing length, the T₃₀ increases first sharply and then slowly. With the scattering increasing, the increment of the T₃₀ is smaller. For an increasing height, the changes of T₃₀ are determined by the absorption and scattering. In terms of the aspect ratio of l/w increasing for a given volume and area, the average SPL values approximately decrease linearly; furthermore, the T₃₀ decreases unless the atrium is extremely high. The T₃₀ is the longest for a flat skylight compared to that of other forms, and it is shorter when the skylight has a slope, including either a single or a double-pitch skylight. It can decrease nearly by 40% when the angle of the lean-to skylight is 7°. The T₃₀ is lower and the amount of decrease is considerably smaller for an increasing slope. When the absorption is evenly distributed in the atria, the skylight has minimal effect on the average SPL or T₃₀ values. Additionally, the classical formula can approximately calculate the SPL distribution unless the atrium is in a form of long space. The Arau-Purchades formula is generally appropriate to predict T₃₀ with uneven absorption distributions unless the absorption or scattering coefficient is low.     

Dynamic sub-grid scale turbulent Schmidt number approach in large eddy simulation of dispersion around an isolated cubical building

In this paper, the effects of the sub-grid scale (SGS) turbulent Schmidt number, Sc _SGS, on the large eddy simulation of dispersion on and around an isolated cubical model building with a flush vent located on its roof are examined. Constant and dynamic Sc _SGS approaches for SGS turbulent mass flux modeling are employed. Simulation results are compared with the available wind tunnel measurements. Furthermore, the influence of the grid resolution on the accuracy of results predicted by the dynamic Sc _SGS approach is investigated. Detailed statistical analysis of Sc _SGS demonstrates that the dynamically computed Sc _SGS at different locations varies by a factor of almost 5 and a considerable deviation of Sc _SGS from its common values of 0.5 and 0.7 occurs. Particularly, in the vicinity of the building where the concentration gradients are noticeable, Sc _SGS has a larger variation. Also, the probability of occurrence of 0.2 < Sc _SGS <1.5 is more than 90 percent and the Sc _SGS mean values are nearly around 0.8 to 1 with a maximum variance of 0.2. In addition, by refining the grid, the differences between the predictions of constant and dynamic Sc _SGS approaches decrease. This is due to the reduction of sub-grid scales contribution to turbulent dispersion. It is confirmed that dynamic Sc _SGS approach is a practical alternative to the constant Sc _SGS approach, effectively eliminating a user-defined model coefficient.     

Monitoring the quality of mineral bottled water concerning to potential pathogenic bacteria and nitrate levels

The diversity of cultured pathogenic bacteria in the bottled mineral water (BMW) was investigated using selective media. The pure isolates from these selective media, which showed hemolytic activity on the blood agar media and antibiotic resistance, were identified by 16S rRNA gene technique. The seven obtained strains were belonged to the genus Pseudomonas, Bacillus, Acinetobacter, Stenotrophomonas, and Exiguobacterium, and were mostly closed to the pathogenic strains. The increasing of ozone concentration from air-fed ozone generators eliminate the growth of bacteria included the pathogenic bacteria, but in other side it increases the amount of nitrates and nitrites in the final product of the BMW. These findings revealed that the BMW either has potential pathogenic bacteria or high levels of nitrates and all these products may effect on the health of the end user.     

The <Emphasis Type="Italic">E. coli</Emphasis> dying kinetics under the effect of ozone

The article has investigated the inactivation kinetics of E. coli under the effect of ozone at its different concentrations, pH values, and temperature of a model solution. We have calculated the rate constants of the pseudofirst order and the activation energy of contamination of test organisms with ozone. We have studied the role of free radicals in contamination processes in the presence of traps for radicals: tert-Butanol alcohol and sodium bicarbonate. It has been shown that in the water free of organic matter, contamination takes place mainly by the molecular mechanism of an ozone effect on microorganisms.     

Capacity variation of polymer membranes in biological fouling with <Emphasis Type="Italic">E. Coli</Emphasis> cells

The paper has studied the processes of the biological fouling of UPM-67, UAM-500, and PAN-20 polymer membranes in filtration through them of an E.coli suspension. The paper gives quantitative indicators of the growth of microorganisms on the surface of the membranes depending on a composition of the water being treated. A correlation between membrane capacity and the amount of the E. coli cells that adhered to their surface was conducted.     

Improving predictions of heat transfer in indoor environments with eddy viscosity turbulence models

Heat transfer modelling in indoor environments requires an accurate prediction of the convective heat transfer phenomenon. Because of the lower computational cost and numerical stability, eddy viscosity turbulence models are often used. These models allow modification to turbulent Prandtl number, and near wall correction which influences stagnation points, entrainment, and velocity and time scales. A modified v ²–f model was made to correct the entrainment behaviour in the near wall and at the stagnation point. This new model was evaluated on six cases involving free and forced convection and room airflow scenarios and compared with the standard k–ε, and k–ω–SST models. The results showed that the modification to the v ²–f model provided better predictions of the buoyant heat transfer flows while the standard k–ε failed to reproduce and underestimate the convective heat transfer. The k–ω–SST model was able to predict the flow field well only for a 2D square cavity room, and 3D partitioned room case, while it was poor for the other four cases.     

Bioindication of natural waters using a histological analysis of the <Emphasis Type="Italic">Carassius Auratus</Emphasis> mesonephros structure

The paper has investigated bioindicator properties of mesonephrosa of goldfish Carassius gibelio Bloch 1782. It has been found a broad spectrum of the action of water-soluble insecticide Bulldog-ES on organs and tissues. The possibility of using a histological criterion for assessing the state of water area has been studied.     

The Effects of Non-uniform Temperature Distribution on Neutral Plane Level in Non-adiabatic High-Rise Shafts During Fires

The location of neutral plane level (NPL) of a high-rise shaft is an important factor for the evaluation of risks of smoke spreads in high-rise buildings, where the shaft internal pressure is equal to that of the building floor at the same height. The current method to determine the location of NPL assumes uniform temperature distribution inside a shaft, which causes concerns over accuracy of the predicted NPL for high-rise shafts with non-uniformly distributed temperatures during fires. To address the effect of temperature distribution on NPL location, this paper introduces a method to calculate temperature distribution and its associated NPL location based on a coupled model of smoke temperature profile, flow rate and pressure distribution inside a shaft. The measured data from a 1/3 scale experiment is used to validate the method and used to develop two empirical equations for NPL locations in terms of dimensionless numbers: one empirical equation based on shaft top temperature and the second based on shaft bottom temperature. A sensitivity study of the empirical equations is then conducted to evaluate the applicability of the developed equations when compared to the existing NPL method. It was found that for the existing NPL equation based on uniform temperature assumption may under-/overestimate the NPL locations, and the NRMSE would be over 50%, while the NRMSE of the empirical equation is only around 6% based on the results of coupled equations. For non-adiabatic shafts, the effects of non-uniform temperature distribution on NPL should be considered and the suggested empirical equations can predict NPL locations with a reasonable accuracy.     

Behavior of thin-walled circular hollow section stub columns under axial compression

Thin-walled steel circular hollow section (CHS) is widely used in wind turbine towers, where the tube is subjected to axial load combined with bending moment. Understanding the behavior of axially loaded thin-walled tubes with large diameter-to-thickness (D/t) ratios is crucial for the design of such structures. To investigate the behavior of axially loaded thin-walled circular hollow section steel tubes, 16 stub columns were tested with the D/t ratio ranging from 75 to 300. The experimental results showed that the compressive strength decreased sharply with the increase of the D/t ratio. The experimental result indicated that the tubes with smaller D/t ratios failed with outward deformation without visible local buckling. With the increase of the D/t ratio, local buckling appeared at the peak load. The finite element method was used to model the behavior of axially loaded stub columns. The experimental results were used to validate the accuracy of the finite element results. Based on the finite element model, the influences of the D/t ratio, the initial geometric deformation and the initial residual stress were analyzed. Design guidelines in Eurocode3, AISC-LRFD, AS4100 and S16-9 on thin-walled steel members were used to compare with the experimental and calculated results. Among them, the results based on AS4100 were the closest to the experimental results.     

Construction and verification of a unified <Emphasis Type="Italic">p</Emphasis>–<Emphasis Type="Italic">y</Emphasis> curve for laterally loaded piles

Estimation of the lateral pile load capacity is the key design procedure for structures where lateral loads are predominant, such as bridges, tall buildings and offshore platforms. In the process of laterally loaded pile design, the p–y curve method is the mainstream method and preferred by designers compared to the elastic continuum or finite element analysis. The traditional p–y curves are derived from some specific field tests and limited data, which do not reflect the overall conditions. In this study, a unified p–y curve based on the stress increment perspective was constructed by introducing Vesic cavity expansion theory and considering the actual stress state of the surrounding soils. The proposed p–y curve combines the contributions of the expansion-induced soil radial stress increment, vertical stress increment and lateral soil resistance caused by deep pile rotation. To validate the proposed method, case examples of lateral pile load tests in various soil conditions were prepared and used to compare the p–y curves from the test results and proposed methods. The p–y curves calculated from the proposed method show reasonable agreement with measured results and give a good prediction in large deformation analysis.     

Investigation of correlations between shear wave velocities and CPT data: a case study at Eskisehir in Turkey

Seismic waves result from fault movement during earthquakes. Depending on the features of the physical environment through which they pass, there are variations in the velocity and amplitude of body waves, which occur underground, and surface waves, which occur on the Earth’s surface. The ratio of shear wave velocity (V _s) to near-surface velocity is a parameter used widely in land use planning to predict the potential for amplified seismic shaking, especially in urban areas. The main objective of this study was to estimate V _s by using cone resistance (q _c) and lateral friction (f _s) for a study area at Eskisehir Graben, to help mitigate geotechnical earthquake engineering problems in civil engineering and land use planning. In geotechnical shallow soil research, certain geophysical methods are used for measuring V _s —a major form of seismic energy propagation—at the near surface. In this study, cone penetrometer data collected from seismic cone penetration tests (SCPT) includes q _c, f _s, and downhole V _s. S-type seismic energy waveforms, which are produced on the surface, were measured at different depths using an S-type geophone in the city center of Eskisehir via SCPT. With SCPT, q _c, friction ratios (R _f), and V _s values were measured at 42 different test points. R _f properties are associated with soil thickness, and these were compared with dynamic soil properties (V _s) using a standard statistical method; we calculated correlations amongst V _s, q _c, and R _f measured from cone penetration tests.