Clean Liquids Research Articles

MODERN INNOVATIVE CLEANING TECHNOLOGIES IN THE FOOD INDUSTRY

This article is devoted to an overview of modern innovative cleaning technologies used in the food industry. The author reviews various methods of cleaning food products, including mechanical, thermal, and chemical methods. Particular attention is paid to the latest purification technologies, such as membrane technology and ion exchange chromatography technology. The author also explores the possibilities of using nanotechnology in the food industry. One of the innovative cleaning technologies in the food industry is membrane filtration. This technology allows cleaning liquids and solutions from impurities, including bacteria and microorganisms, using membranes with different porosity. Membranes can be made of various materials, such as polymers, ceramics, metals and others. Another technology is ultrasonic cleaning, which is used to clean liquids of dirt, including food particles and microorganisms. During the ultrasonic cleaning process, high-frequency sounds are created in the liquid, which results in the creation of waves that break dirt and microorganisms into small particles that can be easily removed. In addition, innovative cleaning methods such as electrophoresis and photocatalytic cleaning are used in the food industry. Electrophoresis uses an electric field to clean liquids and solutions from impurities. Photocatalytic cleaning uses light and catalysts to clean liquids and air of contaminants. In the modern food industry, innovative cleaning technologies make it possible to improve the quality and safety of food products, reduce cleaning costs and preserve the environment. Such technologies are becoming more and more popular in the food industry and allow to provide consumers The article examines the advantages and disadvantages of each cleaning method, as well as its application in various branches of the food industry. Cleaning processes for various products such as milk, crops and meat are described in detail.

Calculate a batch adsorber with a fixed bed of sorbent

There is considered a method to define parameters for the adsorber with the fixed bed of sorbent. The paper reviews constructional features to clean gas-air mixtures and liquids from toxic contaminants.

Numerical simulation and experimental tests of the filter with a rotating cylindrical perforated filter element

There is a need to clean various liquids of solid impurities in almost all areas of human activity. The filter design with a rotating cylindrical perforated filter element was proposed to address this topical technical problem. Its work based on the principle of rotational filtration. The experimental studies demonstrated that with a rotating cylindrical perforated filter element could remove more than 90% of the admixture particles. This took place in defined fluid motion modes, which characterized by the dimensionless Reynolds numbers. In the present study, numerical simulation was carried out for an investigation of the hydraulic oil motion and solid admixture particles' motion in the filter. The simulation results showed a local increase velocity in the holes of the perforated filter element. It entails the passage of a very small particle number into the filtrate. A comparison of the numerical simulation results of filter cleaning efficiency with the data of physical experiments showed a rather good agreement, the discrepancy between which is less than 9%.

Фильтровальные характеристики пористых перегородок из проволочных сеток

The article presents the results of experimental studies of the uneven distribution of the distances between the wires of the warp and weft in woven wire meshes with square cells used to clean gases and liquids from mechanical impurities in various branches of technology. On the basis of experimental data using the methods of probability theory, the regularity of the size distribution of the cells of these grids is determined. The length of its minimum side is chosen as the determining size of a square cell. The results of the conducted studies were used to estimate the fractional coefficient of the leakage of spherical particles through the mesh in the sieve mechanism of separation of these particles from the fluid flow. The probability of particle breakthrough through the grid is assumed to be equal to the fraction of the fluid flow passing through the cells, which determines the size of which is larger than the particle diameter. For experimental verification of the calculated values of the leakage coefficient for the sieve filtering mechanism, a preliminary analysis of the influence of the parameters of the hydrodynamic mode of fluid flow through the grid and the level of fluid contamination on the filtering mechanism was carried out. The results of experimental studies of the fractional leakage coefficient values obtained by the sieve filtering mechanism are compared with the calculated data.

DEFECTS IN LARGE HOLLOW POROUS CYLINDRICAL FILTERS MADE BY SHS

The relevance of research is connected with the use of ceramic filters in biology and medicine for fine filtration of air and biological fluids abroad. Due to the unique combination of chemical and thermal resistance, high strength and thermal conductivity, ceramic filters are used to clean aggressive liquids, superheated high pressure steam and other gases. The dependence of burning rate on the relative density and granulometric composition of FeTiO 3 –Al–Si–SiO 2 –C powder mixtures is studied. The paper provides experimental results on the influence of initial charge compact density and composition on the quality of products obtained. The main types of defects appearing in the synthesis are identified. The causes of defects are found. Feedstock with particle sizes larger than specified values results in penetrations (cavities) occurring in the product. Their formation is caused by the increased liquid phase content in these regions due to decelerating reaction rate and rising temperature. Higher density results in transverse and longitudinal laminations in the product. Such laminations are formed under the pressure of gaseous products with the low gas permeability of the sample that declines as density increases. The technology of self-propagating high-temperature synthesis of large porous products is developed with the photographs of filtering elements presented: for the typical industrial gas burner GG-2, for superheated steam and demineralized water purification (filtering elements used in polyvinyl chloride process vessels at JSC «Sayanskkhimplast»), for iron removal from artesian water. Defect-free large porous products can be obtained with an optimal ratio of the sample grain size distribution and density, as well as reaction rate and heat removal rate.

Shapes of ellipsoidal bubbles in infinite stagnant liquids

Aspect ratios E of ellipsoidal bubbles in infinite stagnant clean liquids are measured for log M = −6.6, −5.5, −4.9 and −3.9, where M is the Morton number. An empirical correlation of E applicable to a wide range of the Morton number is proposed by making use of the present data and Sugihara's data at log M = −11 (2007). The aspect ratio in this correlation is expressed in terms of the combination of the Eötvös number and the bubble Reynolds number to account for the effects of the inertial, viscous, buoyant and surface tension forces on E. Terminal velocities of ellipsoidal bubbles are accurately predicted by using the proposed correlation and a drag correlation proposed by Rastello et al. (2011).

Optimization of novel pyrazolium ionic liquid catalysts for transesterification of bitter apple oil

In the present study, 4 different functionalized pyrazoliums based on sulfoalkyl-pyrazolium hydrogensulfate and alkylsulfo-alakylpyrazolium hydrogensulfate were explored to catalyze biodiesel production from bitter apple oil (BAO). The results demonstrated that a longer chains catalyst of 2-(4-sulfobutyl) pyrazolium hydrogensulfate (SBPHSO4) exhibited the highest catalytic activity, which is attributed to its strong acidity. The highest yield of esters was up to 89.5% when the reaction was carried out under the conditions of 5.2wt% of SBPHSO4, molar ratio of methanol to BAO of 15:1, 170°C, and 800rpm for 6h. These results demonstrated that ionic liquids offer a promising new type of pyrazolium catalyst for biodiesel production. The use of clean ionic liquids in preparing clean biodiesel could solve the drawbacks associated with using the old conventional catalysts and might be employed as an efficient catalyst for such relevance.

Preparation of metal nanoparticles for surface enhanced Raman scattering by laser ablation method

Gold, silver and copper nanoparticles were prepared in clean and biologically-friendly liquids by laser ablation. The average size of nanoparticles ranges from 3 to 30 nm. These nanoparticles were used to fabricate nanostructured substrates for surface enhanced Raman scattering (SERS) measurement. Raman spectra were measured by a Micro-Raman spectrophotometer. The results show that gold, silver and copper nanoparticle substrates fabricated by our method are effective for SERS studies. SERS was also obtained when using gold, silver and copper nanoparticle colloid prepared by laser ablation.

Dynamics and stability of metallic foams: Network modeling

We formulate a large-scale network model for the dynamics and stability of a planar (gas–liquid) foam with low liquid fraction composed of approximately polygonal gas bubbles. We restrict attention to clean liquids (free of surfactants and colloidal particles) as a model for molten metallic foams produced using batch-processing techniques for manufacturing porous-metal solids. The liquid is primarily confined within highly curved regions around the bubble vertices, Plateau borders, interconnected by thin liquid films that form the edges of the bubbles and drain due to capillary-viscous suction. The model incorporates direct coupling between the pressure and area of the bubbles, surface-tension forces on the gas–liquid interfaces and draining and elongational flows in the films. The model also explicitly accounts for van der Waals instabilities that grow to rupture a liquid film once it becomes sufficiently thin, leading to bubble coalescence and hence coarsening of the foam. We consider foams confined wit...

Low-energy excitations and singular contributions in the thermodynamics of clean Fermi liquids

Using a recently suggested method of bosonization in an arbitrary dimension, we study the anomalous contribution of the low energy spin and charge excitations to thermodynamic quantities of a two-dimensional (2D) Fermi liquid. The method is slightly modified for the present purpose such that the effective supersymmetric action no longer contains the high energy degrees of freedom but still accounts for effects of the finite curvature of the Fermi surface. Calculating the anomalous contribution $\delta c(T)$ to the specific heat, we show that the leading logarithmic in temperature corrections to $\delta c(T)/T^2$ can be obtained in a scheme combining a summation of ladder diagrams and renormalization group equations. The final result is represented as the sum of two separate terms that can be interpreted as coming from singlet and triplet superconducting excitations. The latter may diverge in certain regions of the coupling constants, which should correspond to the formation of triplet Cooper pairs.

ChemInform Abstract: Optical Spectroscopy and Ionic Liquids

AbstractReview: 126 refs.

Bubble swarms in power-law liquids at moderate Reynolds numbers: Drag and mass transfer

The motion of and mass transfer from swarms of mono-size non-circulating spherical bubbles in clean power-law liquids have been numerically investigated at moderate Reynolds and Peclet numbers. A simple sphere-in-a-sphere cell model has been used to account for hydrodynamic interactions between neighbouring bubbles. A wide range of values of the gas hold-up has been considered so as to evaluate the detailed drag and mass transfer characteristics of dense swarms of bubbles and of almost single bubbles rising in power-law liquids. Extensive numerical results have been obtained to elucidate the effects of the Reynolds number ( Re), Schmidt number ( Sc), power-law index ( n) and gas hold-up ( Φ) on the drag coefficient and Sherwood number over the ranges of conditions: 0.6 ≤ Φ ≤ 10 −6, 1 ≤ Re ≤ 200, 1 ≤ Sc ≤ 1000 and 0.6 ≤ n ≤ 1.6. The drag coefficient ( C d) decreases, whereas, the average Sherwood number ( Sh avg) increases with the decreasing values of n. However, the effect of the power-law index is found to be more significant on the rising velocity of swarms of bubbles than that on the rate of mass transfer. Based on the present numerical results, predictive correlations have been proposed for drag coefficient and Sherwood number which can be used to estimate the free rising velocity and mass transfer coefficients respectively in a new gas–liquid application involving power-law continuous phase.

Sonoluminescence from transient cavitation at high pressures in water and acetone

In highly degassed, clean liquids, transient acoustic cavitation can be triggered by fast neutrons, a phenomenon that has been known since ∼1960’s. The kinetic energy acquired by the nuclei allows it to ionize a small volume (∼100 nm dia.) in the liquid, creating a vapor cavity that would normally last a couple of microseconds. If the acoustic amplitude and phase are right, this cavity expands by several orders of magnitude (∼500 to 1500 microns dia.) and then collapses, emitting a short flash of light (1 to 40 nsec). The bubble continues to expand and collapse for several hundred cycles, eventually evolving into a larger (2 to 6 mm dia.) bubble cloud which lasts several milliseconds, depending on the conditions. The time duration of the light pulses is longer and their amplitude larger than those of single bubble sonoluminescense in water (∼100 to 300 psec, 105 photons/flash). The amplitude and time evolution of the light flashes has been analyzed as a function of the driving conditions and compared with computer simulations in an effort to infer the maximum plasma temperatures and densities, and perhaps the presence of shock waves, in the cavities.

Theory of many-fermion systems

A general field-theoretical description of many-fermion systems, both with and without quenched disorder, is developed. Starting from the basic Grassmannian action for interacting fermions, we first bosonize the theory by introducing composite matrix variables that correspond to two-fermion excitations and integrating out the fermion degrees of freedom. The saddle-point solution of the resulting matrix field theory reproduces a disordered Hartree-Fock approximation, and an expansion to Gaussian order about the saddle point corresponds to a disordered random-phase approximation (RPA)-like theory. In the clean limit they reduce to the ordinary Hartree-Fock and random-phase approximations. We first concentrate on disordered systems, and perform a symmetry analysis that allows for a systematic separation of the massless modes from the massive ones. By treating the massive modes in a simple approximation, one obtains a technically satisfactory derivation of the generalized nonlinear $\ensuremath{\sigma}$ model that has been used in the theory of metal-insulator transitions. The theory also allows for the treatment of other phase transitions in the disordered Fermi liquid. We further use renormalization group techniques to establish the existence of a disordered Fermi-liquid fixed point, and show that it is stable for all dimensions $d>2$. The so-called weak-localization effects can be understood as corrections to scaling near this fixed point. The general theory also allows for studying the clean limit. For that case we develop a loop expansion that corresponds to an expansion in powers of the screened Coulomb interaction, and that represents a systematic improvement over RPA. We corroborate the existence of a Fermi-liquid fixed point that is stable for all dimensions $d>1$, in agreement with other recent field-theoretical treatments of clean Fermi liquids.

A novel method for sub-micron particle detection in clean liquids

A novel approach to the detection of liquid-borne submicrometer particles (extendible to ultra-clean liquids) is described. The key concept is to coax the submicrometer particles to soft cavitate and then detect the ensuing transient bubble activity acoustically rather than the particle itself (which has only a weak scattering signature). The method, therefore, relies on facilitating microcavitation through Acoustic microcavitation is brought about by low megahertz fields giving rise to micrometer-size bubbles that live a few microseconds. Liquid-borne microparticles do not, ordinarily, cause any cavitation when exposed to strong sound fields (of 1 MHz). If, however, a very weak, high-frequency auxiliary field (e.g., 30 MHz) is added to this sound field, cavitation by the microparticles is readily facilitated. This technique of facilitating cavitation is referred to as acoustic coaxing. Results of preliminary experiments indicate that even smooth spherical microparticles can be coaxed to cause cavitation. An explanation of the acoustic coaxing effect is offered. The physics seems not to be limited by the smallness of microparticles (effect possible up to 50 nm). This novel method based on coaxing of microcavitation promises to be a good basis for on-line, real time monitoring of liquid-borne submicronic particulates. This method is not limited to small sensing volumes and, unlike optical methods, it has an intrinsic, location specific, signal enhancement at the source particle.

Experiments on the rise of air bubbles in clean viscous liquids

A number of new experiments have been performed on the rise of air bubbles in clean mixtures of distilled water and pure, reagent grade, glycerine covering a range of the relevant parameter, the Morton number, Mo = gv4ρ3/σ3, of 1013. Here g is the acceleration due to gravity, v the kinematic viscosity, ρ the density and σ the surface tension of the mixture. In these careful measurements several scaling regimes have been found that have not been discussed before in the extensive literature on the subject. The transitions between these regimes have been delineated and attempts made to discuss the dynamical processes that might be important in each of them.

Linearity of the vortex meter as a function of fluid viscosity

The vortex phenomenon has found many applications in flow metering. The vortex shedding flowmeter is recommended for use with relatively clean liquids, high pressure gases and vapours, but is not recommended for high viscosity liquids. In this paper we describe experiments concerning the dependence of the linearity on the fluid viscosity.

A device with linear characteristics for measuring instantaneous discharge: Application to the case of fluctuating discharge

The study ofaflowmeter patented in 1971 is presented. The apparatus is needed essentially for the flowofgas and has some very interesting features particularly in so far as linearity sensitiveness and frequency response are concerned. It can be fitted to already existing pipes needing only cheap modifications and causes no pressure drop in the flow. This flow measurement technique can be easily extended to the flow of clean liquids.

Clean Liquids and Gaseous Fuels from Coal for Electric Power

The development of processes for coal-gasification, power-generating systems requires large capital expenditures. To obtain a test at an operational scale of about 100 MW, in which the developed system can be considered commercially available, usually requires a typical time schedule of 3--8 years and funding levels of 100--200 million dollars. World events as well as technical factors will decide whether the solutions under current development will be timely. It is recognized that the successful completion of the tasks will be an achievement for the worldwide electricity community. Both liquefaction and gasification will have an important place in the future economic production of electric power. The power industry will have a need to convert hundreds of millions of tons of coal to clean fuels. (Summary)

Mass transfer from single bubbles in Newtonian liquids

The constant volume technique developed by Calderbank has been used for measuring the instantaneous mass transfer rates for single carbon dioxide bubbles with 0·46< d 0<0·85 cm in n-propanol, i-butanol, acetic acid, distilled water and n-octanol aqueous solution. The decay of mass transfer coefficient with bubble age was observed even in clean pure liquids, and the degree of the decay was high for the system of small bubble and the liquid where the solubility and the diffusivity of carbon dioxide were large. An empirical equation for mass transfer coefficient has been proposed taking the effect of bubble age into account.