Method to assess safety of packaging polymer materials for thermal processing of vacuumised food products

FIELD: measurement equipment.

SUBSTANCE: invention relates to analytical chemistry of food production facilities. The method to assess safety of packing polymer materials for thermal processing of vacuumised food products includes formation of a polymer material in the form of a packet, its vacuumising, sealing and thermal processing, after which the packet is thermostatted at room temperature, 5.0 cm3 of dried air is pierced into it with a syringe, and in 5 minutes, not taking the syringe out, they take 3.0 cm3 of air. The produced sample is introduced into a tight cell of detection in a "piezoelectronic nose" device, which comprises an array of seven mass-sensitive piezosensors. They record variation of signals of piezosensors in pairs of equilibrium gas phase of the sample for 60 s with the interval of 1 s, the highest responses of piezosensors are formed into a mass-aromogram of maxima, the area of the mass-aromogram is calculated. Under identical conditions they analyse the standard sample of the polymer material. Assessment of safety of the polymer material is carried out by comparison of the area of mass-aromograms of the analysed sample and the standard sample. Difference of the area of mass-aromograms by more than 30.0±1.0% certifies non-compliance of the sample with the standard of the polymer package.

EFFECT: invention makes it possible to assess the level of possible emission of highly volatile compounds from polymer materials in process of thermal processing with increased accuracy and reduction of analysis time.

2 dwg, 1 tbl

 

The invention relates to analytical chemistry of food industry, namely to evaluate the safety of polymer packaging materials for vacuum heat treatment of food products with the use of an array of quartz crystal resonators with the prior modification of electrodes by sorbents of different nature (the system of "purpose piezoelectronic nose").

Packaging of polymeric materials for food products are tested on the content of organic solvents, monomers, however, changing technology heat cooking of food products, including pre-vacuum packaging, can lead to contamination of food by hazardous substances released in hard industrial conditions such as heating in a vacuum, in which the possible emission of toxic polymers the monomers.

An object of the invention is to provide a method of assessing the safety of polymer packaging materials for vacuum heat treatment of food products, allowing to estimate the possible level of emission of volatile compounds from polymeric materials that can cause contamination of the vacuum food during thermal processing, without complicated multi-stage preparation of samples and sophisticated equipments that ensure you�will fetter performance the correctness, accuracy, reduced time of analysis and ease of determination.

To solve the technical problem of the invention proposes a method for assessing the safety of polymer packaging materials for vacuum heat treatment of food products, characterized in that the polymeric material formed in the form of the package is evacuated, sealed, followed by heat treatment, after which the polymer batch was incubated at room temperature, injected him with a syringe 5.0 cm3dehumidified air and in 5 minutes, without removing the syringe, select 3.0 cm3air, is introduced into a sealed cell detection devices purpose piezoelectronic the nose consisting of an array of seven mass-sensitive piezosensors on the basis of quartz crystal resonators of the BAW type with a base frequency of 10.0 MHz with diverse film sorbents from solutions of politicolegal of sebacina, dicyclohexano-18-crown-6, polyethylene glycol, Triton X-100, trioctylphosphine, 4-aminoantipyrine, nitrate Zirconia weight 5,0-10,0 µg on the electrodes, register change signals piezosensors in pairs equilibrium gas phase sample for 60 c with an interval of 1 second, with most of the responses piezosensors form a sum signal of all sensors in the mass aromathrapy highs, races�Citywest area mass aromatherapy, which is a quantitative measure of the content of volatile substances in an air sample, in identical conditions, analyze the sample-standard polymer material, and the safety rating of the polymeric material is carried out by comparing the square of the mass aromathrapy samples and samples of the standard, the difference of the square of the mass aromathrapy more than 30,0±1,0%, indicates the discrepancy of the sample standard plastic packaging.

The technical result of the invention consists in the estimation of potential emissions of volatile compounds from polymeric materials, without complicated multi-stage of sample preparation and sophisticated equipment, providing high performance, correctness, accuracy, reduced time of analysis and ease of determination.

The proposed method of assessing the safety of polymer packaging materials for vacuum heat treatment of food products is as follows.

Preparation of the detecting device "purpose piezoelectronic nose" is as follows. Form an array of seven piezoresonator with a base frequency of 10.0 MHz. The electrodes of piezoresonator with two sides Microstream evenly applied certain volumes of individual sorbents from solutions of politicolegal of sebacina (PDAGS), dicyclohexano-18-crown- (DCH-18-K-6), polyethylene glycol (PEG-2000), Triton X-100 (TX-100), trioctylphosphine (TOPO), 4-aminoantipyrine (AAP), nitrate Zirconia (AZr), followed by static evaporation of free solvent in a drying oven or a desiccator over a desiccant bed. Modified piezoresonator cooled in a desiccator over a desiccant bed to 20.0±2,0°C. the Completeness of the removal of the solvent confirms the constancy of the oscillation frequencies of piezoresonator with films (piezosensor). Piezosensor fixedly secured in the holders on the lid of the cell detecting device "purpose piezoelectronic nose."

Sample preparation. Packaging the polymeric material formed in the form of the package is evacuated, sealed, followed by heat treatment, after which the polymer batch was incubated at room temperature, injected him with a syringe 5.0 cm3dehumidified air and in 5 minutes, without removing the syringe, select 3.0 cm3air, is introduced into a sealed cell detection devices purpose piezoelectronic nose."

The measurement of the analytical signal "purpose piezoelectronic nose". Air samples quickly Inuktitut in the cell of the detecting device. Simultaneously record the frequency of oscillation of piezosensors at 1-second intervals for 60 s. For the recovery of the modifiers piezosensor regenerated in a drying Cabinet at relocateamerica sorbents for 2-5 min or perform purging of the cell detecting device for 5-7 min.

The total signal purpose piezoelectronic nose" is formed in the form of mass aromathrapy artificial fragrance. The algorithm of reading signals and generating mass aromathrapy, and the number of piezosensors in the array is optimized to achieve the maximum differences total analytical signal (mass aromathrapy) for the sample standard.

As a test standard selected sample of polymeric material corresponding to GOST R 12302-2003 "Packages of polymer and composite materials. General technical conditions".

Sample-standard build standard mass aromatherapy responses of an array of seven mass-sensitive piezosensors received within 60 S. In identical conditions analyze samples of polymeric materials of different manufacturers. Their mass aromatherapy compared with the standard mass-hromatography. Mismatch type and area mass aromathrapy more than 30,0±1,0% of the sample is rejected as non-conforming to requirements of normative documents.

A method for evaluating the safety of polymer packaging materials for vacuum heat treatment of food products is illustrated by the following example.

Preparation of the detecting device. The seven electrodes piezosensors with natural frequency of 10 MHz modify evenly with two sides� microspace solutions politicolegal of sebacina (PDAGS), dicyclohexano-18-crown-6 (DCH-18-K-6), polybag.-langille (PEG-2000), Triton X-100 (TX-100), trioctylphosphine (TOPO), 4-aminoantipyrine (AAP), nitrate Zirconia (AZr) to obtain the mass of the film after 5-10 µg static evaporation of free solvent in a desiccator over a desiccant bed or in a drying Cabinet at a temperature of 50.0±1.0°C for 20 min. the Modified piezoresonator (piezosensor) cool in a desiccator over a desiccant bed to 20.0±1,0°C.

Piezosensor fixedly secured in the holders on the lid and placed in a sealed cell of the detecting device "purpose piezoelectronic the nose with a volume of 50.0 cm3.

Sample preparation samples of packaging plastic materials is as follows: packaging the polymeric material formed in the form of the package is evacuated, sealed, followed by heat treatment, after which the polymer batch was incubated at room temperature injected him with a syringe 5.0 cm3dehumidified air and in 5 minutes, without removing the syringe, select 3.0 cm3air.

The measurement of the analytical signal "purpose piezoelectronic nose". The air sample is injected by a syringe into the cell detecting device "purpose piezoelectronic nose." Responses of piezosensors is recorded by computer at 1-second intervals for 60 seconds Signals plesase�of Sora's form in the mass aromathrapy (Fig. 1).

When analyzing samples of the received standard mass aromatherapy, defined as the standard (Fig. 1).

The modifiers piezosensors regenerated in a drying Cabinet at a temperature of 50.0±1.0°C within 5 min. After cooling in a desiccator to 20.0±2.0°C they are used for subsequent determination.

Obtained air samples from various plastic packaging manufacturers (sample No. 1-2) of 2.0 cm is introduced in series in the cell detection system "purpose piezoelectronic nose." Build mass aromatherapy air of the analyzed samples (Fig.2). Comparison of mass aromathrapy several samples of polymeric packaging allows for compliance with the selected standards. The mismatch type and area mass aromathrapy more than 30,0±1,0% indicates a mismatch between the sample standard plastic packaging. It is established that the content of volatile compounds composition of the air of the three polymeric packages varies considerably. The total area of the mass aromathrapy standard plastic packaging is taken as 100%, and the square of the mass aromathrapy samples recalculated relative to this value (tab. 1).

For the analyzed samples it was revealed that sample # 1 meets the standard, differences geometry of mass-aromathrapy not exceed 30,0±1,0%, and are 28,90%. Sample # 2 plastic packaging does not conform to the accepted standards�, as it contains a large amount of volatile impurities, as evidenced by the value of the total analytical signal "purpose piezoelectronic nose" (differences geometry of mass-aromathrapy exceed 30,0±1,0%, and are 1134,0%). Polymer packaging material No. 2 is not recommended for vacuum packaging and subsequent heat treatment of food. Way feasible.

The stability of the selected films can repeatedly apply the modified piezoresonator (piezosensor) - the number of cycles of sorption update work without films modifiers of more than 200. The loss of the film by weight after 200 cycles of sorption does not exceed 1.0%. The reproducibility of measurements of 10.0%, the duration of the analysis, including the modification of electrodes is 40 min; repeated measurements for one sample 10 min, performance analysis 6-8 samples/hour.

Changing the conditions of the experiment: the increase or decrease in the number of sensors increase or decrease the mass of films modifiers that change their nature, the algorithm for constructing the kinetic mass aromathrapy reduces the metrological reliability and sensitivity of the measurements, reducing the degree of difference of mass aromathrapy, reducing the number of measurements without updating the coatings of piezoresonator, as well as to a breakdown of self-oscillations of piezoresonator and nevozmozhno�and implementation method.

The proposed method of assessing the safety of polymer packaging materials for vacuum heat treatment of food products allows

to assess the possible level of emission of volatile compounds from polymeric materials, without complicated multi-stage preparation of samples;

to reduce inspection time and increase productivity definition due to the repeated use of an array of piezosensors without updating working films-sorbates;

- stage to simplify the visualization of the results in the mass aromatherapy, which significantly reduces the stage of deciding about the quality of the sample without the involvement of highly qualified personnel.

A method for evaluating the safety of polymer packaging materials for vacuum heat treatment of food products, characterized in that the polymeric material formed in the form of the package is evacuated, sealed, followed by heat treatment, after which the polymer batch was incubated at room temperature, injected him with a syringe 5.0 cm3dehumidified air and in 5 minutes, without removing the syringe, select 3.0 cm3air, is introduced into a sealed cell detection devices purpose piezoelectronic the nose consisting of an array of seven mass-sensitive piezosensors on the basis of the QCM rezonatorov type with a base frequency of 10.0 MHz with diverse film sorbents from solutions of politicolegal of sebacina, dicyclohexano-18-crown-6, polyethylene glycol, Triton X-100, trioctylphosphine, 4-aminoantipyrine, nitrate Zirconia weight 5,0-10,0 µg on the electrodes, register change signals piezosensors in pairs equilibrium gas phase sample for 60 c at 1-second intervals, with the greatest responses of piezosensors form a sum signal of all sensors in the mass aromathrapy highs, calculated the size of the mass aromatherapy, which is a quantitative measure of the content of volatile substances in an air sample, in identical conditions, analyze the sample-standard polymer material, and the safety rating of the polymeric material is carried out by comparing the square of the mass aromathrapy samples and samples of the standard, the difference of the square of the mass aromathrapy more than 30,0±1,0% indicates a mismatch between the sample standard plastic packaging.



 

Same patents:

FIELD: test equipment.

SUBSTANCE: invention refers to material test methods. Essence of the invention: a sample is first strained to the maximum set deformation, held in this deformation for a given time, compressed to the initial unloaded state, left in it for a given time, with further cyclic deformation with delays in each deformation stage of compression and tension, where at each tension cycle the set deformation is less than at the previous cycle, and the set deformation at each unloading cycle is larger than in the previous cycle.

EFFECT: more information on material properties from a sample test, new information represented by equilibrium stress-strain curve, dissipation loss, material softening after each tension/compression cycle, and relaxation curves together with material structure recovery curves for various deformations.

2 cl, 1 dwg

FIELD: measurement equipment.

SUBSTANCE: invention relates to measurement equipment, in particular, to devices for measurement of profile of surfaces of low-modular viscoelastic sheet materials of light industry, namely, man-made and natural leathers, etc. A device to detect profile of materials in deformed condition, comprising a base, a counting unit, a locating element, installed as capable of rotation around its axis, differing by the fact that the locating element is made in the form of a semi-cylinder with a hollow semi-cone and two limiting plates to fix a sample; the device comprises an additional counting unit fixed on the semi-cylinder, to detect bending radius of the investigated sample, arranged in parallel to the semi-cone guide, at the same time the main counting unit is made as combined, capable of displacement along the axis of rotation of the locating element and comprises a strain gauge motion sensor and a digital optical microscope.

EFFECT: device makes it possible to study hidden defects of natural leather and man-made materials, to determine variation of material relief under bending deformation.

2 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: disclosed is a method of determining the glass-transition point of tetrazole-based polymer composite materials based, according to which the glass-transition point is determined from the change of slope of a curve of temperature versus the inverse of dielectric constant 1/ε'=f(T).

EFFECT: high accuracy and reliability of determining the glass-transition point of tetrazole-based polymer composite materials.

4 dwg, 1 tbl

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to oncology, and can be used for recognising synchronous multifocal colorectal carcinoma. Substance of the invention consists in measuring preoperative blood follicle-stimulating hormone both in male and female patients suffering from colorectal carcinoma. If its concentration falls within the range of 26.01 to 60.91 IU/l in the females and of 2.71 to 5.67 IU/ml in the males, a single tumour is diagnosed in the patients, and if the hormone concentration is from 2.70 to 5.50 IU/ml in the females and from 12.88 to 52.04 IU/l in the males, the presence of synchronous colorectal new growths are stated. The method can be implemented at the preoperative stage; it is easily reproducible in the oncology hospital environment.

EFFECT: stating the presence of synchronous multifocal colorectal carcinoma.

6 ex

FIELD: chemistry.

SUBSTANCE: invention relates to field of producing carbon-carbon composite materials for various purposes, and is intended for comparative characteristic of impregnation of carbon fibre (CF) braids with melts of pitches, and can be used in improvement of technologies of producing carbon-carbon composite materials, possessing various properties, by modification or replacement of pitch binder and/or carbon fibre, for instance, in research laboratories, in particular, in carrying out laboratory work. To determine degree of impregnation of carbon fibre braids with pitches, carbon fibre braid is placed into glass tube in such a way that the end of braid protrudes from glass tube, and carbon fibres in braid are oriented along glass tube axis, with braid thickness being selected in such a way that it tightly fits glass tube, protruding end of carbon fibre braid is brought in contact with melted pitch and keep in such position, after which carbon fibre braid is extracted from tube and height of impregnation of carbon fibre braid with pitch is determined.

EFFECT: simplification and acceleration of determination are achieved.

1 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: method involves cutting a sample for analysis and analysing its chemical composition, from which the rubber brand is determined. The sample is cut such that it has pre-decomposition zones. Chemical composition is analysed from a fracture in the sample by X-ray spectral technique on a scanning electron microscope with an energy-dispersive spectrometer. The obtained data on chemical composition of the sample are compared with chemical composition of a known rubber brand or a rubber brand used as a reference.

EFFECT: high accuracy and objectivity of determining a rubber brand.

3 ex, 1 tbl, 2 dwg

FIELD: chemistry.

SUBSTANCE: method involves titration of a suspension with a solvent which is soluble in water and dissolves the suspended resin-like substance until reducing light scattering, which is determined either visually or using optical devices which enable to measure the amount of light passing through the liquid.

EFFECT: rapid estimation of the amount of resin-like substance suspended in water.

3 dwg

FIELD: physics.

SUBSTANCE: apparatus has a clamp mechanism for holding material, an indenter for loading with possibility of measuring its displacement and recording information into a processor. A sensor is built into the indenter, said sensor being sensitive to the spectrum of acoustic emission generated by a sample upon change of deformation characteristics thereof. The clamp mechanism is in form of two coaxially placed cups with built-in heating elements with a controlled temperature range and a sensor for said temperature.

EFFECT: broader technological capabilities of the apparatus and high measurement accuracy.

2 dwg

FIELD: chemistry.

SUBSTANCE: before testing in a heat chamber, samples of polymer materials are activated with UV radiation in the 248-365 nm wavelength range for 3-30 minutes with radiation power density of 1-15 mW/cm2. Analysis of volatile organic compounds is carried out while comparing the obtained chromatograms of gas samples collected from the heat chamber when testing samples of polymer materials with selected additives based on nanostructured bentonite powder and nanostructured bentonite powder intercalated with metal ions - magnesium (Mg2+ ), scandium (Sc3+), chromium (Cr3+), manganese (Mn2+), iron (Fe2+), cobalt (Co2+), nickel (Ni2+), copper (Cu2+), zinc (Zn2+), tin (Sn2+), cerium (Ce3+) or a mixture of bentonite powders intercalated with ions of said metals. The results of comparing chromatograms of gas samples are used to evaluate the effect of nanocomponents on the predicted sanitary-chemical properties of the designed polymer materials.

EFFECT: realisation of the present invention widens technological capabilities and increases reliability of results of evaluating the effect of modifying mineral nanocomponents on predicted sanitary-chemical properties based on release of volatile organic compounds from the designed polymer materials.

8 cl, 7 ex, 2 tbl, 4 dwg

FIELD: textile, paper.

SUBSTANCE: at the first stage the organoleptic analysis of tested samples is carried out. At the second stage the microscopic analysis of the material structure is carried out. At the third stage the chemical analysis of the tested samples is carried out by means of their treatment with an organic dissolvent selected from the group: butyl ether of acetic acid, dimethylketone, dimethylformamide, tetrahydrofuran, furfural, cyclohexanol at the ratio of sample-dissolvent equal to 1:(10-15) at the boiling temperature of the selected dissolvent for 20-30 minutes. If a sample has dissolved fully, the conclusion is made that is pertains to leather-like materials, and if a sample has not dissolved, it is identified as leather.

EFFECT: accurate and reliable recognition of leather from leather-like materials.

2 cl, 3 ex

Conductometer // 2549246

FIELD: measurement equipment.

SUBSTANCE: conductometer comprises an alternating voltage generator (1), the outlet of which is connected to a reference inlet of a converter (2) code-voltage and to a transformer differential conductometric converter (3). The transformer converter (3) comprises the first (4), second (5) and third (6) transformers, the first communication element (8), covering cores of the first (4) and third (6) transformers, and the second communication element (11), covering cores of the second (5) and third (6) transformers. It also comprises the first wire communication winding (9), between the first (4) and third (6) transformers, the outlets of which are connected to the first terminal block (14), and the second wire communication winding (12), between the second (5) and third (6) transformers, leads of which are connected to the second terminal block (15). The first lead of the first winding (7) of the first transformer (4) is connected to the outlet of the alternating voltage generator (1), the reference inlet of a synchronous detector (17) and the reference inlet of the converter (2) code-voltage, the outlet of which is directly connected to the first lead of the first winding (10) of the second transformer (5). The control inlet of the converter (2) code-voltage is connected to the outlet of a control unit (18). The first lead of the first winding (13) of the third transformer (6) is connected to the inlet of a selective amplifier (16), the outlet of which is connected with the control inlet of the synchronous detector (17), the outlet of which is connected in series with a control unit (18), a microcontroller (19) and a digital indication device (20). The second leads of the first windings of all three transformers are connected to the common bus of the device.

EFFECT: increased accuracy of measurement and expansion of functional capabilities, possibility of precision measurement of active conductivities and resistances.

1 cl, 2 dwg

FIELD: measurement equipment.

SUBSTANCE: device comprises a speed sensor, an electrode sensor and a voltage source. It is also fitted with a microcontroller, an information input and output device, a microampermeter, an adjustable inductance coil, a greasing device, a resistance and a key, and the electrode sensor is designed as a capacitor comprising two semi-cylinders isolated from each other. The key is connected to the microcontroller the outputs of which are connected to the voltage source, the adjustable inductance coil, the greasing device and to the information input and output device, and inputs to the speed sensor, the microampermeter and the information input and output device. The resistance, the condenser, the adjustable inductance coil, the voltage source and the microampermeter are connected in series. The voltage source is a high frequency voltage source.

EFFECT: improvement of efficiency and decrease of error of determination of quality of extended products.

2 cl, 1 dwg

FIELD: measurement equipment.

SUBSTANCE: measuring vessel with a capacitance sensor installed in the form of a multi-electrode flat-parallel air capacitor, to which a measurement capacitor of available capacity is connected, filled with the investigated gas, and the value of temperature and pressure are recorded. High DC voltage is supplied to the capacitance sensor installed in the measurement vessel and to the measurement capacitor of available capacity. The outlet voltage is measured on the measurement capacitor, and moisture content of the investigated gas is determined according to the temperature moisture characteristic of the sensor.

EFFECT: increased sensitivity.

2 cl, 6 dwg

FIELD: measurement equipment.

SUBSTANCE: sensor of the device represents a thick-walled tube-dowel 1, made of a dielectric plastic material, on the outer cylindrical surface of which there are current electrodes 2 and 3, split by plastic dielectric gaskets 4 and on the reverse side. The tube-dowel with electrodes is inserted into a hole 6, previously drilled in the solid medium, and is spaced in it with a screw 10 screwed into it. Gaskets 4 and 5 are installed perpendicularly in a current line 8, flowing in the solid medium. A current recorder 9 is connected between current electrodes 2 and 3. A rotary lever-indicator 11 is fixed on the upper part of the dielectric tube perpendicular to the split of the tube-dowel.

EFFECT: increased accuracy of current density measurement in local volumes of solid media.

2 cl, 1 dwg

FIELD: textiles, paper.

SUBSTANCE: invention relates to textile industry and can be used in control systems of transporting the textile material during technological processing in the form of a tow. The method of detecting a seam of the textile material processed in the form of a tow comprises placing the movable textile material inside the induced coil of the oscillating circuit, amplification and detection of the high frequency voltage at the output of the generator and forming while reducing voltage at the output of the amplifier-detector of the pulse of required duration for safe operation of the actuator. And the seam of the textile material is provided with a conductive label, the amplitude of high frequency voltage is set from the conditions of the required sensitivity at the output of the generator, the voltage is converted at the output of the amplifier-detector and it is compared with the driving voltage, and the resulting difference of voltage is integrated, and the voltage is applied at the output of the integrator to stabilise the amplitude of high frequency voltage at the output of the generator, and the integration process is interrupted for the period of the formed impulse action. The conductive label is used, for example, as a metallised thread, which is used for sewing the textile material pieces in the continuous web.

EFFECT: increase in reliability of detection of the seam of textile material processed in the form of a tow and providing automatic compensation of external disturbing effects.

2 cl, 1 dwg

FIELD: textiles, paper.

SUBSTANCE: invention relates to the field of engineering for light industry and can be used to create the systems for detecting metal particles in textile materials, in nonwoven substrate in production of synthetic leather, felt, etc. The method of detecting metal particles in the displaced fibrous material consists in placing the displaced fibrous material in the working area of induced coil of oscillating circuit in which high-frequency oscillations are created using the generator. Further, amplification and detection of high-frequency output voltage of the generator is carried out. At that at the output of the amplifier-detector the impulse of the required duration for reliable operation of the actuating mechanism is formed. The output voltage of the amplifier-detector is compared with driving voltage. The resulting voltage difference is integrated, and the voltage is applied at the output of the integrator to stabilise the amplitude of high-frequency voltage at the generator output, and the integration process is interrupted for the duration of the impulse formed.

EFFECT: increase in reliability of detection of metal particles in the displaced fibre material and providing automatic compensation of external disturbing actions.

1 dwg

FIELD: textiles, paper.

SUBSTANCE: invention relates to the field of engineering for light industry and can be used to create systems to detect metal particles in textile materials, in nonwoven substrate in production of synthetic leather, felt, etc. The method of detecting metal particles in the movable fibrous material consists in placing the movable fibrous material into the workspace of induced coil of the oscillating circuit in which using a generator the high-frequency oscillations are generated. Then, amplification and detection of high-frequency voltage at the output of the generator is carried out. And at the output of the amplifier-detector the impulse of the required duration is formed for safe operation of the actuator. From the conditions of the required sensitivity the amplitude of high-frequency voltage is set at the output of the generator, the voltage is converted at the output of the amplifier-detector and it is compared with the driving voltage. The obtained voltage difference is integrated and the voltage at the output of the integrator is used for stabilisation of the amplitude of high-frequency voltage at the output of the generator. And the process of integration is interrupted at the time of formation of the impulse for the time interval, the value of which is defined as a functional dependence on the linear velocity of the fibrous material, and the process of integration is renewed at the end of the pulse and the time interval of interruption of the integration process, and at the time of bringing the circuit into operation state the actuation of the actuator is blocked for the time interval, obviously longer than the duration of damped transitory processes in most inertial node of the circuit.

EFFECT: increase in reliability of detection of metal particles in the movable fibrous material and providing automatic compensation of external disturbing effects.

1 dwg

FIELD: chemistry.

SUBSTANCE: method of determining chlorobenzene in natural and waste water using gas chromatography and equilibrium vapour analysis includes determining chlorobenzene on a chromatographic capitally column in a carrier gas current which is nitrogen; generating and detecting the investigated ions formed in a flame with a flame-ionisation detector. The method also includes preparing a basic solution using a more viscous ethylene glycol solvent, hence the basic solution is well preserved for 2 months at temperature in the range of -2°C to -10°C; preparing calibration solutions for chlorobenzene concentration in the range of 0.0003-0.02 mg/dm3; sample preparation, calibrating the chromatograph by perforating the vapour phase of the prepared concentrations; plotting a calibration curve; sample preparation for the analysed water samples; perforating the vapour phase into the evaporator of the chromatograph. The obtained data are processed using ChemStation software which comes in a set with the MAESTRO 7820A chromatographic kit, and qualitative identification and quantitative content of the determined substance is obtained.

EFFECT: improved consistency and accuracy of analysis, shorter duration of the method and easier analysis in environmental monitoring conditions.

6 tbl, 2 dwg

FIELD: chemistry.

SUBSTANCE: system consists of two peristaltic pumps, a loop-containing injector, a flow amperometric cell with includes a biosensor, a potentiostat. As the biosensor, the electroanalytic system contains a lactate biosensor. The injector loop includes an accumulative column.

EFFECT: increase of selectivity and sensitivity of determination, reduction of the limit of lactate detection.

2 cl, 2 dwg, 1 tbl

FIELD: measurement equipment.

SUBSTANCE: scope of application: for carbon monoxide detection in air. Invention consists in the following: manufacturing method includes obtaining nanocrystalline wide gap semiconducting oxides MeO (SnO2, ZnO, In2O3), obtaining sols of quantum dots of narrow gap semiconductors CdX (X=Se, Te, S) and oxides impregnation with sols of quantum dots followed by drying for formation of heterocontacts MO/CdX.

EFFECT: providing possibility of decrease of semiconductive sensor materials temperature to the room temperature upon detection of carbon monoxide in air and providing high sensitivity and low energy consumption of sensor.

2 cl

FIELD: thermal and nuclear power stations; meter calibration in extremely pure water of condensate type and power unit feedwater.

SUBSTANCE: for pH-meter calibration ammonia whose concentration varies by 1.5 - 2 times is dosed in working medium. Electric conductivity and temperature of working-medium H-cationized sample are measured. Measurement results are processed in computer with aid of set of equations characterizing ionic equilibrium in source sample and H-cationized samples. Calculated pH value is compared with measurement results.

EFFECT: enhanced precision and reliability of meter calibration in extremely pure waters.

1 cl, 1 dwg, 1 tbl

Up!