Bulk Liquid Concentration Research Articles

Remote Identification and Estimation of the Calcium Concentration in Bulk Liquid under High-Pressure Condition

Remote Identification and Estimation of the Calcium Concentration in Bulk Liquid under High-Pressure Condition

Remote identification and ranking of Sodium in bulk liquid under high pressure condition

Laser Induced Breakdown Spectroscopy (LIBS) based spectral and temporal measurements are carried out to identify and rank the Sodium in bulk liquid under high pressure condition. The experiments are carried out by varying the incident laser irradiance (4 to 5 * 1011 W/cm2), ambient pressure condition (1 to 8 atm) and stand-off collection distance (0.6 to 2 m). The concentration of Sodium Chloride (NaCl) in the sample solution is varied between 250 and 1500 ppm. From the spectral data, the Na I emission line (589 nm) is visualized for all experimentation condition. Emission due to singly ionized atom and doubly ionized atom are not observed, due to the requirement of high ionization energies. It is observed that the Na I (589 nm) peak intensity decreases with increase in ambient pressure condition, due to the plasma condensation effect. It is also observed that the Na I (589 nm) peak intensity increases with increase in incident laser irradiance. Temporal measurement based quantification of Sodium in bulk liquid is carried out. It is observed that the plasma emission time period (Na I at 589 nm) increases with increase in NaCl concentration. This is related to the re-excitation of neutral atoms (Na I) in the plasma state. In the stand-off distance analysis, it is observed that the plasma (Na I) emission peak intensity and time period of emission decreases with increase in stand-off collection distance. This might be due to the low coupling of plasma emission to the measurement system, at longer stand-off distances. The Na detection limit of about 10 ppm is achieved for a laser irradiance of 3 * 1011 W/cm2. The above specified detection limit is obtained for an ambient pressure condition of 1 atm and stand-off collection distance of 0.6 m. On a summary, remote LIBS with temporal measurement is highly suitable to identify and rank the Sodium concentration in bulk liquid under high pressure condition. However, the calibration of LIBS measurements at different experimental condition is required to utilize the instrument in real-time environment.

Plastic media reduced algal wall-growth of Chlorococcum humicola for the cultivation in internal-loop airlift photobioreactor

During the cultivation of Chlorococcum humicola in airlift photobioreactors, significant wall-growth biofilm was observed, leading to severe light limitation and decreased biomass production. Experiments were conducted, therefore, to assess the possibility of using plastic media to reduce algal wall-growth on the inside surface of photobioreactors. As a result, lab-scale internal-loop airlift photobioreactors were built and operated using different commercial plastic media (MB5 and beads) and aeration rates (0.6 to 1.0 vvm). Without plastic media, significant wall-growth biofilm was observed on the draft tube and the lower section of photobioreactors. It was noted that when MB5 and beads at 5% and 10% by volume of photobioreactor were used, significantly lower biofilm attachment was seen on the surface and biomass concentration in bulk liquid increased 25% as compared to that without plastic media. The separation of plastic media from algal biomass and liquid was easy due to the specific gravity of the media slightly less than that of water.

Start-up of single-stage partial nitritation-anammox micro-granules system: Performance and microbial community dynamics

By manipulating influent nitrogen load and DO concentration in bulk liquid, the start-up and performance of a new micro-granule based partial nitritation-anammox process was investigated in a continuous stirred tank reactor (CSTR). Under the condition of nitrogen loadings from 0.3 to 1.4 kgN /m³/d and DO <0.21mg/L, the single-stage partial nitritation-anammox (SPNA) system was successfully started, with a nitrogen removal of 76.2%. Meanwhile, the oxygen utilization efficiency by ammonium oxidizing bacteria (AOB) increased in the system with the increase of influent ammonia loading rate. Micro-granules with an average diameter of 0.25 mm were formed. Sludge granulation was promoted by increasing influent nitrogen load, and there was a positive correlation between nitrogen load, extracellular polymeric substances (EPS) content and sludge particle size. Ca. Kuenenia became the dominant anaerobic ammonium oxidizing bacteria (AnAOB) in the SPNA system. As the dominant AOB genera, Nitrosomonas coexist with Ca. Kuenenia in the micro-granules.

Aqueous ionic liquid solutions for boiling heat transfer enhancement in the absence of buoyancy induced bubble departure

Advantage of high heat transfer during boiling is lost due to the absence of buoyancy induced bubble departure in space. Absence of bubble departure with pure water on an inverted heater in earth gravity (-1g) resembles boiling behavior in space and is often used to mimic zero-gravity (0g) boiling experiments on earth. Here we perform experiments on an inverted heater to show that unlike water, the aqueous solution of surface active ionic liquid (IL) avoids coalescence to form multiple small bubbles with significantly large wet area on the heater surface. The force of repulsion due to the interaction of ILs adsorbed at the liquid–vapor interface of neighboring bubbles induces a completely passive bubble departure away from the inverted heater surface against the combined effect of buoyancy and surface-tension. Resulting rewetting of the heater surface increases the critical heat flux (CHF) to ≈950kW/m2, which is an enhancement of ≈4.5× in comparison to pure water. Effect of bulk liquid subcooling and concentration on pool boiling CHF are extensively investigated. The mechanism of CHF is explained with the help of the adsorption dynamics of IL at the solid–liquid and liquid–vapor interface of bubbles.

Fast Start-up of ANAMMOX and the Spatial Distribution of EPS in ANAMMOX Granules

An anaerobic sequencing batch reactor(ASBR) inoculated with activated sludge was employed to investigate the start-up of anaerobic ammonium oxidation(ANAMMOX) process and the spatial distribution of extracellular polymeric substances(EPS) in ANAMMOX granules. The results showed that the removal rates of NH4+-N and NO2--N reached more than 99%. The removal rate of total nitrogen(TN) was 89.87%±0.43% and the TN removal load in the ASBR was 1.7 kg·(m3·d)-1. The ratios of nitrite consumption and nitrate production to ammonium consumption were 1.32±0.08 and 0.24±0.03, respectively. Besides, the pH and the effluent nitrate concentration in bulk liquid were considered as two simple indicators for rapid diagnosis of ANAMMOX performance. The proteins(PN) was the main component of EPS in ANAMMOX granular sludge. The PN and polysaccharides(PS) in ANAMMOX granules were (59.61±5.64) mg·g-1 and (12.21±2.04) mg·g-1, respectively, with the ratio of PN/PS reaching approximately 4.88±1.39. β-D-glucofuranose and dead cells were distributed in the outermost layer of granules, while living cells, PN, lipids, α-glucosamine and α-mannose were distributed throughout the granules and mainly concentrated on the outside of granules. PN and lipids constituted the framework of ANAMMOX granules and ANAMMOX bacteria were embedded among the PN and lipids matrix.

Accelerated onset of cellular breakdown at increased solidification speed after laser melting of indium in silicon

We report on the incidence of cellular breakdown in silicon wafers implanted with indium and pulsed laser melted at varying laser fluence. We predict from heat flow calculations that as laser fluence is decreased, (a) the melt depth decreases, (b) the solidification velocity increases, and (c) the solidification front should be more stable with respect to cellular breakdown (based on the binary alloy solidification theory), which should result in observed incidence of cellular breakdown at a relatively shallower depth below the surface. However, secondary ion mass spectrometry (SIMS) data show that cellular breakdown at lower fluence is observed deeper, indicating that the interface became unstable earlier in its solidification. The SIMS data show significant In evaporation, with greater evaporation occurring as fluence increases. Calculations show that surface evaporation can reduce the bulk liquid concentration during solidification, reducing the degree of instability. The longer melt durations after irradiation at higher fluence give more time for evaporation, which may result in a relatively larger delay in the onset of breakdown compared to lower fluence by suppressing the bulk liquid concentration and suppressing the growth of unstable perturbation. Under certain conditions, this effect could dominate over the role of reducing the interface speed, which would tend to accelerate amplification of a perturbation, which leads to breakdown. Calculations qualitatively support this interpretation.

Influence of process dynamics on the microbial diversity in a nitrifying biofilm reactor: Correlation analysis and simulation study.

For engineers, it is interesting to gain insight in the effect of control strategies on microbial communities, on their turn influencing the process behavior and its stability. This contribution assesses the influence of process dynamics on the microbial community in a biofilm reactor for nitrogen removal, which was controlled according to several strategies aiming at nitrite accumulation. The process dataset, combining conventional chemical and physical data with molecular information, was analyzed through a correlation analysis and in a simulation study. During nitrate formation, an increased nitrogen loading rate (NLR) resulted in a drop of the bulk liquid oxygen concentration without resulting in nitrite accumulation. A biofilm model was able to reproduce the bulk liquid nitrogen concentrations in two periods before and after this increased NLR. As the microbial parameters calibrated for the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in both periods were different, it was concluded that the increased NLR governed an AOB and NOB population shift. Based on the molecular data, it was assumed that each period was typified by one dominant AOB and probably several subdominant NOB populations. The control strategies for nitrite accumulation influenced the bulk liquid composition by controlling the competition between AOB and NOB. Biotechnol. Bioeng. 2016;113: 1962-1974. © 2016 Wiley Periodicals, Inc.

Physicochemical mechanisms of plasma-liquid interactions within plasma channels in liquid

The goal of this study is to advance the fundamental understanding of the physical and chemical mechanisms by which excited radical species produced by electrical plasmas directly in water, OH radicals especially, induce chemical changes in aqueous organic compounds and to exploit this for the development and optimization of drinking and wastewater plasma-based treatment systems. To achieve this goal, this study measured and correlated the production rate of hydrogen peroxide (H2O2) with physicochemical properties of 11 organic compounds. The observed individual correlations between the investigated physicochemical properties and the resulting H2O2 concentrations were used to develop an equation that would allow predicting the measured H2O2 concentration from physicochemical properties of a compound.Results reveal that the production rate of H2O2 directly depends on the surface tension of the solution and compounds’ bulk liquid concentration, hydrophobicity (Kow value), and molecular volume. Other properties such as vapor pressure, Henry’s constant, enthalpy of vaporization, ionization energy, electron affinity, and molecular dipole moment do not affect the H2O2 chemistry. Kow value and surface tension of the solution determine the compound’s concentration at the plasma interface. Once at the interface, the molecular volume determines the rate at which the molecule will react with OH radicals.

Modelling microbial competition in nitrifying biofilm reactors.

A large variety of microbial parameter values for nitrifying microorganisms has been reported in literature and was revised in this study. Part of the variety was attributed to the variety of analysis methods applied; it also reflects the large biodiversity in nitrifying systems. This diversity is mostly neglected in conventional nitrifying biofilm models. In this contribution, a one-dimensional, multispecies nitrifying biofilm model was set up, taking into account the large variety of the maximum growth rate, the substrate affinity and the yield of nitrifiers reported in literature. Microbial diversity was implemented in the model by considering 60 species of ammonia-oxidizing bacteria (AOB) and 60 species of nitrite-oxidizing bacteria (NOB). A steady-state analysis showed that operational conditions such as the nitrogen loading rate and the bulk liquid oxygen concentration influence both the macroscopic output as well as the microbial composition of the biofilm through the prevailing concentration of substrates throughout the biofilm. Considering two limiting resources (nitrogen and oxygen), the coexistence of two species of the same functional guild (AOB or NOB) was possible at steady state. Their spatial distribution in the biofilm could be explained using the r- and K-selection theory.

An analytical model for local-nonequilibrium solute trapping during rapid solidification

Updated version of local non-equilibrium diffusion model (LNDM) for rapid solidification of binary alloys was considered. The LNDM takes into account deviation from local equilibrium of solute concentration and solute flux fields in bulk liquid. The exact solutions for solute concentration and flux in bulk liquid were obtained using hyperbolic diffusion equations. The results show the transition from diffusion-limited to purely thermally controlled solidification with effective diffusion coefficient DLNDMb→0 and complete solute trapping KLNDM(v)→1 at v→vDb for any kind of solid-liquid interface kinetics. Critical parameter for diffusionless solidification and complete solute trapping is the diffusion speed in bulk liquid vDb. Different models for solute trapping at the interface with different interface kinetic approaches were considered.

Local non-equilibrium diffusion model for solute trapping during rapid solidification

A local non-equilibrium diffusion model (LNDM) for rapid solidification of binary alloys has been briefly reviewed and used to modify a number of solute trapping models with different solid–liquid interface kinetics. The LNDM takes into account deviation from local equilibrium of a solute diffusion field in bulk liquid on the basis that the exact solutions to hyperbolic diffusion equations govern the solute concentration and solute flux in bulk liquid under local non-equilibrium conditions. The LNDM leads to a velocity-dependent effective diffusion coefficient in bulk liquid ahead of the solid–liquid interface DbLNDM(V), which goes to zero when the interface velocity V→VDb, where VDb is the bulk liquid diffusion speed. The results show an abrupt transition from diffusion-limited to purely thermally controlled solidification, with the diffusion coefficient in bulk liquid DbLNDM(V)=0 and complete solute trapping KLNDM(V)=1 at a finite interface velocity V=VDb for any type of solid–liquid interface kinetics. The bulk liquid diffusion speed VDb is a critical parameter for the transition. The velocity dependence of partition coefficients KLNDM(V) has been calculated for different types of solid–liquid interface kinetics, with allowance for local non-equilibrium diffusion effects. The calculation shows that the local non-equilibrium partition coefficients KLNDM(V) reduce to the standard K(V) at low interface velocity (V≪VDb) and differ substantially at high interface velocity (V∼VDb).

Explicit Formula for Estimation of the Enhancement Factor for Absorption with (&lt;i&gt;m&lt;/i&gt;,&lt;i&gt;n&lt;/i&gt;)th-Order Reaction

An approximate explicit formula for the enhancement factor in the case of irreversible (m,n)th-order gas–liquid reactions is derived. The formula is applicable in both the slow- and fast-reaction regimes. The accuracy of the formula has been tested by comparing it with the exact numerical solution of the film model. The comparison is made over wide ranges of the Hatta number, ratio of bulk liquid concentration to interfacial concentration of the gaseous reactant, and other parameters of the reaction system. The overall mean percentage deviation of the approximate formula is within 5% for m=1 and integer orders n in the range [1,3], while the deviation is within 19% for n=1 and integer orders m in the range [1,3].

A Theoretical Analysis of Dissolved-Gas Transfer to the Bulk Liquid in Gas Absorption with a First-Order Reaction

A theoretical analysis using the surface-renewal and film-penetration models, which includes gas-phase resistance to mass transfer, is presented for the rate of absorption of a gas and its transfer to the bulk liquid in the case where the solute gas undergoes a first-order chemical reaction in the liquid phase. It reveals that: a. The fraction of absorbed gas transported to the bulk liquid depends upon the Hatta number Ha in case of the surface-renewal model and on Ha as well as a dimensionless hydrodynamic parameter in case of the film-penetration model. b. The widely assumed law of addition of resistances is valid for the surface-renewal and film-penetration models. c. The reaction influences both the overall mass-transfer coefficient and the nature of the driving force, i.e. the increased rate of absorption due to the reaction is not solely due to the enhancement factor multiplying the liquid-phase mass-transfer coefficient for physical absorption as has been conventionally assumed in the literature. It is also shown that in a gas-liquid reactor the film and surface-renewal models give close predictions for both the rate of absorption and concentration of dissolved gas in the liquid leaving the reactor. For values of Ha ⩾ 0.5, the bulk-liquid concentration of dissolved gas predicted by both models is negligible compared to its interfacial concentration.

G0600-5-3 ブタノール水溶液のミニチャネル内流動沸騰特性(熱工学部門一般講演(5):伝熱(5))

Some alcohol solutions such as butanol show non-linear surface tension dependence. It is known that dryout of the heat surface is inhibited by Thermal Marangoni Effect of non-linear surface tension. These solutions are called Self-rewetting Liquids. Boiling heat transfer of butanol aqueous solution is studied in experimental systems of forced convection boiling. This test is also performed inside a mini channel. Mass flux is 1286kg/m^2s or 2374kg/m^2s, subcooling was changed from 0K to 50K. Bulk liquid concentration changed from 0.00wt% to 7.15wt%. Wall temperature was measured by using thermocouple and radiation thermometer. At high mass flux (G=2374kg/m^2s), CHF of butanol aqueous solution is from 20% to 50% higher than that of pure water in subcooled region. Burnout of butanol aqueous solution was Fast Burnout (Upper stream CHF).

Liquid film effect on dynamics of optical oxygen probe. Comparison with polarographic oxygen probes. Diffusion coefficients measuring technique

Abstract The dynamic behaviour of the optical oxygen probe at the presence of the liquid film is well described by unsteady one-directional oxygen diffusion into the probe membrane through liquid film. It is shown that the asymmetry caused by hyperbolic form of the Stern–Volmer relation between the probe signal and oxygen concentration is strongly suppressed in the presence of liquid film for the optical probes used in this work. In such case, the response calculated with respect to the mean oxygen concentration in the membrane describes well the optical oxygen probe dynamics. Liquid film effects on the signal of the optical and the polarographic oxygen probes are compared. Special attention is paid to find properties of membranes minimizing the liquid film effect on the rate of its response. From this point of view, the most suitable material for the optical probe membrane is one with high diffusivity but low solubility. Thus, silicone (used by optical probe manufacturers in these days) is the least suitable material. When both probes are covered with the same membrane, the response of polarographic probe is faster and less influenced by the liquid film compared with optical one. From this point of view, the polarographic probe is more suitable for monitoring of fast changing oxygen concentration in bulk liquid as it occurs, e.g. measurement of k L a in gas–liquid dispersions, usually with the need to know the L L parameter characterizing the liquid film diffusion resistance. In addition, only the polarographic probe allows determination of a local value of the parameter L L (under the given hydrodynamic conditions where the probe is situated) which is not possible with an optical probe. The optical probe is more suitable for measurements under steady-state conditions and for slower oxygen changes, even under the conditions, when the liquid film resistance is high in comparison with the membrane resistance as it occurs for diffusivity measurements in liquids. A modified method for evaluation of the oxygen diffusion coefficient in liquids from the dynamic probe response is presented.

CrossRef Listing of Deleted DOIs

Analog castings of two geometrical forms have been studied to observe the effect of continuously changing the direction of gravitational force on patterns of segregation. Molds of slab form, cooled on one side, and of cylindrical form, cooled at the base, were rotated axially at rates from 0 to 10 rpm with the axis of rotation tilted from 0 to 30 deg to the vertical: the development of “A” channel segregation in the former and of “freckel” channels in the latter were recorded photographically, while changes in bulk liquid concentration were followed over time periods up to one hour. It was observed that changing the direction of gravitation, slowly and continuously, markedly retarded or eliminated the formation of segregation channels and that consequent macrosegregation was also retarded and reduced. The application of the principle to foundry practice is discussed.

Performance and microbial ecology of the hybrid membrane biofilm process for concurrent nitrification and denitrification of wastewater

We report on a novel process for total nitrogen (TN) removal, the hybrid membrane biofilm process (HMBP). The HMBP uses air-supplying hollow-fibre membranes inside an activated sludge tank, with suppressed aeration, to allow concurrent nitrification and denitrification. We hypothesised that a nitrifying biofilm would form on the membranes, and that the low bulk-liquid BOD concentrations would encourage heterotrophic denitrifying bacteria to grow in suspension. A nitrifying biofilm was initially established by supplying an influent ammonia concentration of 20 mgN/L. Subsequently, 120 mg/L acetate was added to the influent as BOD. With a bulk-liquid SRT of only 5 days, nitrification rates were 0.85 gN/m(2) per day and the TN removal reached 75%. The biofilm thickness was approximately 500 lim. We used DGGE to obtain a microbial community fingerprint of suspended and attached growth, and prepared a clone library. The DGGE results, along with the clone library and operating data, suggest that nitrifying bacteria were primarily attached to the membranes, while heterotrophic bacteria were predominant in the bulk liquid. Our results demonstrate that the HMBP is effective for TN removal, achieving high levels of nitrification with a low bulk-liquid SRT and concurrently denitrifying with BOD as the sole electron donor.

Influence of hydrogen on the reductive dechlorination of tetrachloroethene (PCE) to ethene in a methanogenic biofilm reactor: role of mass transport phenomena

AbstractThis study investigated the influence of H2 bulk liquid concentration in the range 2–120 µmol L−1 on the kinetics of vinyl chloride (VC) formation from tetrachloroethene (PCE) and VC dechlorination to ethene in a methanogenic biofilm reactor containing Dehalococcoides spp. as the putative dechlorinating micro‐organism. Both VC formation and dechlorination showed a definite increase in rate with increasing H2 bulk liquid concentration, following a pattern typical of Michaelis–Menten kinetics. The estimated maximum VC formation rate (81.7 ± 9.4 µmol L−1 h−1; mean value ± 90% confidence interval) was about ten times higher than the estimated maximum VC dechlorination rate (8.2 ± 1.0 µmol L−1 h−1), while the estimated apparent half‐velocity coefficient for H2 for VC formation (1.5 ± 1.4 µmol H2 L−1) was more than six times lower than that for VC dechlorination (9.1 ± 5.1 µmol H2 L−1), confirming that the last step of PCE dechlorination (i.e. conversion of VC to ethene) was much more H2‐sensitive than the previous ones. The estimated maximum methane formation rate was 462.1 ± 213.5 µmol L−1 h−1 and the estimated apparent half‐velocity coefficient was 104.7 ± 89.4 µmol H2 L−1. Experiments at different temperatures indicated the presence of severe internal (diffusional) mass transfer limitations and, in turn, of steep H2 concentration gradients through the biofilm, which strongly influenced the estimated apparent half‐velocity coefficients for H2 use. The results of this study emphasise the importance of considering mass transfer phenomena when predicting the rate of PCE dechlorination and the outcome of competition for H2 in natural or engineered bioremediation systems. Copyright © 2006 Society of Chemical Industry

Modeling chromatographic columns: Non-equilibrium packed-bed adsorption with non-linear adsorption isotherms

In this work a new mathematical model, based on non-equilibrium conditions, describing the dynamic adsorption of proteins in columns packed with spherical adsorbent particles is used to study the performance of chromatographic systems. Simulations of frontal chromatography, including axial dispersion, for non-equilibrium systems with non-linear adsorption isotherms are made and compared to those of the experimentally determined protein A affinity chromatography breakthrough curves of hIgG, gathered from the literature. The non-equilibrium model developed here combines external mass transfer and intra-particle transport by solid (surface) diffusion, and permits the prediction of (time and bed height dependent) interface and average solid concentrations, along with interface and bulk liquid concentrations. The present non-equilibrium approach significantly improved the model predictions of experimentally observed distended breakthrough fronts over local equilibrium based models, and can be used to evaluate the influence of system parameters on the performance of chromatographic packed-bed adsorption columns.