159 results about "Freeze thaw cycling" patented technology

The invention discloses a low-temperature type wood-plastic floor and a preparation technology thereof. The floor comprises substances of: plastic particles, plant fiber, a filling material, a compatibilizer, a lubricant, a pigment, and functional auxiliary agents. Compared with existing technologies, according to the invention, melted and modified plastic particles are adopted, the components are well formulated, and the mold of the product is improved. Under a temperature of -34 DEG C to 60 DEG C, the linear expansion coefficient of the prepared product is smaller than 5*10<-5>. When the product is processed through three times of freeze-thaw cycling tests according to ASTM D6109-10, the bending strength retention of the product is more than 97%.

The invention discloses polymer cement antiseptic paint and a preparation method thereof which includes the steps of respectively mixing solidoid materials and liquidoid materials to be even, gradually adding the solidoid materials into the liquidoid materials, and blending thoroughly until no bladders exist; wherein the liquidoid materials include 10-50wt% of epoxy emulsion, 0-30wt% of vinyl acetate-ethene copolymer emulsion, 0-30wt% of cinnamene-acrylate copolymer emulsion, 0-1wt% of organosilicon defoamer and 2-10wt% of polyene polyamine hardener; the solidoid materials include 20-39wt% of cement, 8-19wt% of quartz sand and 0-2wt% of cellulose. The polymer cement antiseptic paint has high strength, high bending resistance, high viscosity, corrosion resistance and aging resistance and is flameproof, nontoxic and safe to use during construction; therefore the polymer cement antiseptic paint is ideal material for the sections or parts that are high in concentration of sulfate, moisture evaporation, freeze-thaw cycling, dry-wet alternation or hydraulic scour and are exposed to sulfate corrosion.

The invention discloses a preparation method of a hemostatic sponge, comprising the following steps: (1) dispersing oxidized cellulose powder into water to obtain 0.1-2.0wt% of oxidized cellulose dispersion, and then homogenizing the oxidized cellulose dispersion under high pressure to obtain a nanooxidized cellulose suspension; (2) injecting the nanooxidized cellulose suspension into a mold, performing 1 to 7 times of freeze-thaw cycles to obtain nanocellulose hydrogel, freezing the nanocellulose hydrogel for sizing, and then drying to obtain the hemostatic sponge; wherein one freeze-thaw process is: freezing for 8-16 h at -40 to -18 DEG C, and then unfreezing for 8-16 h at 4-25 DEG C. The invention also provides the hemostatic sponge prepared by the preparation method. The hemostatic sponge has high carboxyl content, high porosity and water absorption capacity, and can quickly absorb excess blood on the wound surface to achieve effective hemostasis.

The invention discloses a real-time monitoring system and method for frost heaving deformation expansion of rock ice-containing cracks. The real-time monitoring system for frost heaving deformation expansion of rock ice-containing cracks comprises a CT scanning system, a rock freezing and thawing system, a crack deformation measuring system and a frost heaving force measuring system. The CT scanning system comprises a vertical rack, an area array detector, an X-ray transmitter, a rotating system and a base. The rock freezing and thawing system comprises a water storage barrel, a freezing barrel and a freezing circulation system, the water storage barrel is located above the freezing barrel, a rock sample is placed in the freezing barrel, the freezing barrel is installed on the rotating system, and the freezing circulation system is connected with the freezing barrel; the fracture deformation measuring system and the frost heaving force measuring system are connected with the rock sample and are respectively used for measuring the deformation condition and the frost heaving force change condition of the rock sample in the freezing process; according to the invention, frost heaving deformation of rock fractures can be measured, and the expansion evolution mesoscopic process of rock ice-containing fractures under the action of freeze-thaw cycle can be observed in real time.

The invention discloses a prediction method for long-term deformation of freeze-thaw damaged soft rock, provides a dangerous rock body deformation judgment criterion for geotechnical engineering construction in a cold region, and guarantees the safety of foundation engineering in whole life cycle use. The method comprises the following steps: (1) constructing a freeze-thaw aging damage variable multivariate function; (2) constructing a freeze-thaw aging damage coupling creep mechanics constitutive equation in combination with a freeze-thaw aging damage variable multivariate function; (3) performing standard regulation sampling on the on-site soft rock, and recording the change value of the strain of the rock sample along with the stress and time; (4) carrying out nonlinear fitting on the strain time curve and the constitutive equation to determine each mechanical parameter in the equation; (5), converting the rock mechanics parameters into rock mechanics parameters; (6) determining equivalent freeze-thaw cycle times through an indoor and outdoor freeze-thaw cycle equivalent equation; (7) actually measuring the spatial distribution rule and displacement increment of a rock mass stress field on site; and (8) predicting a strain value corresponding to the rock mass at a future tf moment.

The invention relates to a nondestructive prediction combination method for evaluating rock uniaxial compressive strength under freeze-thaw cycle. The nondestructive prediction combination method comprises the following steps: preparing a plurality of standard rock samples from a complete rock block of a rock to be tested; continuously and repeatedly carrying out freeze-thaw circulation on the plurality of standard rock samples until the standard rock samples are damaged; in the repeated freeze-thaw cycle process, after five freeze-thaw cycles are completed each time, performing a measurementprocess, and according to the mass, the longitudinal wave velocity and the porosity, calculating the limit uniaxial compressive strength of the rock to be measured by using a uniaxial compressive strength formula. According to the nondestructive prediction combination method, the porosity of the rock and the trend of the internal fracture are jointly determined through the ultrasonic technology and the nuclear magnetic resonance technology, the macroscopic integrity of the rock is controlled through the weight, the microcosmic and macroscopic structures of the rock are controlled, and prediction of the uniaxial compressive strength of the rock is more accurate.

A method of controlling a physical characteristic of polymeric nanocarrier-encapsulated protein particles includes altering or selecting a weight percentage of a hydrophobic polymer block in a total amphiphilic diblock copolymer of a primary emulsion of a double emulsion, freeze-thaw technique. The primary emulsion is formed using a freeze-thaw cycle of the amphiphilic diblock copolymer and a protein having a molecular weight of up to or equal to 300,000 Da. Selection of the hydrophobic polymer block percentage alters one or more characteristics of the resulting nanoparticles, such as shape. Thus, as one aspect, a method of producing filamentous polymeric nanocarrier-encapsulated protein (i.e., active enzyme) particles involves forming a primary emulsion using a freeze-thaw cycle of (i) an amphiphilic diblock copolymer, which has a molecular weight of about 10,000 to about 100,000 Da and comprises a conjugate of the hydrophobic polymer block and a hydrophilic polymer block, wherein the amphiphilic diblock copolymer comprises greater than 81% to about 95% by weight of the hydrophobic polymer block; and a protein having a molecular weight of up to or equal to about 300,000 Da. Various compositions comprising such filamentous-shaped nanocarrier particles, and methods of use for diagnosis and therapy are disclosed.

The invention discloses freeze-thaw resistant recycled concrete and a preparation method thereof. The concrete is prepared from the following raw materials: Portland cement, fine aggregate, coarse aggregate, water, a water reducing agent, an air entraining agent and rubber powder; the fine aggregate comprises organic silicon resin modified recycled fine aggregate, and the coarse aggregate comprises organic silicon resin modified recycled coarse aggregate. The rubber powder and the air entraining agent provide an expansion space for free water expansion in the recycled concrete, the expansion stress in the recycled concrete is reduced, meanwhile, the surface of the recycled aggregate is coated with the organic silicon resin, the water absorption of the recycled aggregate is reduced, and the freeze-thaw resistance of the recycled concrete is improved; and the modified recycled aggregate is tightly connected with a cement gel system, so the interior of the recycled concrete is compact, and the compressive strength of the recycled concrete is enhanced.

The invention discloses a method for determining freezing-thawing damage degree of a rock in a high-altitude cold region. The method comprises the following steps: selecting a high-altitude cold region rock sample, drying the sample to a constant weight, cooling the sample, and saturating the sample with water; performing freeze-thaw cycle treatment on the water-saturated sample, measuring the gaspermeability of the sample under the same confining pressure under the same osmotic pressure after different freeze-thaw cycles, drawing a change curve of the gas permeability of the rock with different freeze-thaw cycles, and fitting the curve; defining a calculation formula of a freezing-thawing damage quantity D: D = 1 - (ki/k0),wherein k0 is the gas permeability of the sample before freezingand thawing, ki is the gas permeability of the sample after i freezing-thawing cycles, and i=1, 2, 3, 4...; and drawing a change curve of the freezing-thawing damage quantity of the rock with the number of freezing-thawing cycles, fitting the curve by a function, and determining the according to the degree of rock damages caused by any freezing-thawing cycle according to the fitting function. Themethod defines the freezing-thawing damage quantity of the rock by the gas permeability of the rock, and makes a test result accurate, scientific and reliable.

The invention discloses an unsaturated roadbed soil freeze-thaw cycle model test system, relates to a freeze-thaw cycle test device, and aims to solve the problem that an existing freeze-thaw cycle test device cannot truly and accurately reflect the comprehensive influence of temperature, moisture and load in the actual freeze-thaw cycle process, wherein the device comprises a test bin, a controlsystem and a data acquisition system, and the test bin comprises a sleeve, a heat preservation body and a water permeable part; a test piece is loaded in the sleeve, the side wall is hermetically wrapped with a thermal insulator, and the water permeable part is arranged at the bottom; the control system comprises a temperature control system, a moisture control system and a load control system; the temperature control system comprises a temperature control chamber, an upper temperature control disc and a lower temperature control disc; the temperature control chamber covers the test bin; the upper temperature control disc and the lower temperature control disc are respectively arranged at the top and the bottom of the sleeve; the moisture control system is communicated with the bottom of the test piece through a water supplementing pipe; the load control system is arranged at the top of the sleeve; the data acquisition system comprises a temperature acquisition system, a moisture acquisition system and a displacement acquisition system.

Belonging to the technical field of building materials, the invention discloses a concrete composite air entraining agent, its preparation and use methods. The composite air entraining agent is composed of sodium dodecyl sulfate (14-60%), beta-cyclodextrin (30-84%), Arabic gum (1-8%), and bone gum (1-10%). The component raw materials are stirred evenly by physical and mechanical mixing, thus obtaining the concrete composite air entraining agent. During use, the dosage of the air entraining agent accounts for 0.004%-0.03% of the weight of cement in concrete. The concrete composite air entraining agent provided by the invention has the advantages of wide raw material sources, simple production method and excellent product performance, can introduce a lot of small, uniform and stable bubbles into concrete, enhances the water-retaining property of green concrete, improves workability, reduces slump loss, also greatly improves the freeze-thaw cycling resistance, salt-freezing resistance and other durability indicators of concrete, and has small negative influence on the strength of a hardened body. The concrete composite air entraining agent provided by the invention can be used in reinforced concrete, lightweight aggregate concrete, artificial aggregate concrete, bridges, buildings, hydraulic engineerings, pavements and other structures.

The invention provides a rock damage acoustic monitoring device and method in a freeze-thaw dry and wet environment, and relates to the technical field of rock engineering. The rock damage acoustic monitoring device in the freeze-thaw dry and wet environment comprises a sample tank, a dry-wet circulating system which is used for supplying water to the top of the rock sample placed in the sample tank; a freeze-thaw circulating system which is used for adjusting the temperature of the rock sample placed in the sample tank; and an acoustic wave emission probe which is used for acquiring damage information of the rock sample. The dry-wet circulating system can simulate a rainfall environment by supplying water to the top of a rock sample, and the freeze-thaw circulating system simulates the freeze-thaw state of the rock so as to simulate the frost heaving inoculation evolution process of the rock mass in the cold region. The acoustic wave emission probe receives ultrasonic waves and sound emission signals and monitors the development, communication and damage process of the freeze-thaw cycle rock mass microfractures. The device can accurately monitor the space-time evolution process of the microscopic damage of the rock sample in the freeze-thaw dry and wet environment, and reveals the performance degradation mechanism of the rock mass in the complex environment.

The invention belongs to the technical field of thawing rocks, and discloses a method for obtaining unfrozen water content in rocks under freeze-thaw cycle conditions, and the method comprises the following steps of preparing rock column samples, and saturating the rock column samples with formation water; performing a nuclear magnetic resonance test on the rock column samples of saturated formation water to obtain a T2 spectrum curve; converting the T2 spectrum curve into a nuclear magnetic pore throat distribution curve f(r); bringing the nuclear magnetic pore throat distribution curve f(r)into an integral formula to respectively obtain the relationship curve between unfrozen water content and temperature during melting and freezing. The method for obtaining the unfrozen water content in rocks under the freeze-thaw cycle conditions provided by the invention can achieve high accuracy and high reliability, and is easy to obtain the unfrozen water content.

A method of controlling a physical characteristic of polymeric nanocarrier-encapsulated protein particles includes altering or selecting a weight percentage of a hydrophobic polymer block in a total amphiphilic diblock copolymer of a primary emulsion of a double emulsion, freeze-thaw technique. The primary emulsion is formed using a freeze-thaw cycle of the amphiphilic diblock copolymer and a protein having a molecular weight of up to or equal to 300,000 Da. Selection of the hydrophobic polymer block percentage alters one or more characteristics of the resulting nanoparticles, such as shape. Thus, as one aspect, a method of producing filamentous polymeric nanocarrier-encapsulated protein (i.e., active enzyme) particles involves forming a primary emulsion using a freeze-thaw cycle of (i) an amphiphilic diblock copolymer, which has a molecular weight of about 10,000 to about 100,000 Da and comprises a conjugate of the hydrophobic polymer block and a hydrophilic polymer block, wherein the amphiphilic diblock copolymer comprises greater than 81% to about 95% by weight of the hydrophobic polymer block; and a protein having a molecular weight of up to or equal to about 300,000 Da. Various compositions comprising such filamentous-shaped nanocarrier particles, and methods of use for diagnosis and therapy are disclosed.

The invention relates to a three-sample linkage freeze-thaw test system for the real-time simulation of freeze-thaw process of soil. A test box body is composed of a working chamber, a refrigeration unit, an air conditioning air supply device, a control system and a safety protection system; a water supply system monitors and observes the change of water and the state of the pore water pressure inreal time in the freeze-thaw process of a sample; a cold source circulation tank system adopts an integrated structure formed by a drawer type layout in a cold bath tank; a refrigeration system adopts a high-precision temperature and humidity control system, so the refrigeration system is effectively and safely protected; the air conditioning system control system automatically achieves dynamic balance and achieves the purpose of temperature change; an electrical measurement and control system ensures the automatic degree of the system, and important parameters in the test process are displayed by a human-computer interaction interface; and the safety protection system protects the safe running of the system in real time. The three-sample linkage freeze-thaw test system has the characteristics of real time, high efficiency, safety, stability, automation, convenient energy saving, simple simulation process, good stability and reliability, and high precision.

The invention discloses an automatic dry-wet freeze-thaw cycling test device which comprises an operation platform, a control module, an evaporation module, a spray module, a weighing module, a refrigeration module and a manipulator operation module, wherein the spray module controls a peristaltic pump through a pulse control sent by the control module to complete the control on the water additionamount; the weighing module detects the quality through a pressure sensor and completes the quality control and data collection; the refrigeration module adopts a refrigeration box; and the manipulator operation module controls a stepping motor to realize the walk in any position in a two-dimensional space through the control module. The invention also discloses an automatic dry-wet freeze-thaw cycling test method. According to the test method, a signal is sent to the control module according to an input parameter instruction, and the whole process of a wet-dry freeze-thaw cycling test is completed through cooperation of each module. The test device and the test method provided by the invention are professionally used for the dry-wet freeze-thaw cycling test of loess, thereby realizing the fully-automatic control of the test, improving the test precision, reducing the personnel investment and lowering the production cost.

The invention discloses a rock-soil body freeze-thaw stress coupling creep test instrument and test method in a water environment. The test instrument comprises a hydraulic control system, a water pressure control system, a freeze-thaw circulating system, a temperature control system and a data acquisition system. A rock-soil body sample is placed in a pressure-bearing barrel of the triaxial creeptest device, confining pressure is applied to the rock-soil body sample through a water pressure control system, axial pressure is applied to the rock-soil body sample through a hydraulic control system, a freeze-thaw cycle system provides freeze-thaw cycle working conditions for the test through a refrigerating machine and a heating machine, and a temperature control system monitors and controlsthe temperature in the pressure-bearing barrel; after the axial pressure and the water pressure are stable, a rock-soil body sample triaxial creep test is carried out, and a data acquisition system acquires test data in the test process in real time. The invention also provides a rock-soil body freeze-thaw stress coupling creep test method in a water environment. According to the invention, the triaxial creep test of the rock-soil body is carried out in a freeze-thaw cycle environment, and the efficiency and precision of the test are effectively improved.

The invention discloses a test device for simulating a dry-wet cycle and a freeze-thaw cycle of a roadbed soil body. The test device comprises a test cylinder main body, a temperature and humidity sensor is hermetically arranged in the test cylinder main body along each detection channel in a penetrating manner, and the temperature and humidity sensor is electrically connected with the input end of a data acquisition instrument, a channel filtering piece is fixed in the outer discharging channel, and a hydraulic jack is fixed to the bottom face of a beam of the portal frame. The device has theadvantages that the hydraulic jack compacts a soil sample in the test cylinder main body, when the dry-wet cycle test is carried out, the low-temperature constant-temperature tank dries the soil sample, the low-temperature constant-temperature tank is removed, water is injected into the temperature control layer, and the dry-wet cycle test is repeatedly carried out to complete the dry-wet cycle test, when a freezing and thawing cycle test is carried out, the low-temperature constant-temperature tank repeatedly circulates the soil sample to carry out cooling freezing and heating thawing, in the dry-wet cycle and freeze-thaw cycle test process, the data monitored by the temperature and humidity sensor is fed back to the data acquisition instrument in real time, and the device is simple to operate, time-saving, labor-saving and low in investment cost.

The invention discloses a method for determining joint shear strength considering freeze-thaw cycle damage. Aiming at the complexity of rock mass joints in cold regions, the method provided by the invention deeply analyzes the relationship between the joint connectivity and the shear strength, and proposes a calculation formula of shear strength parameters changing along with the joint connectivity based on an indoor test, so that the shear strength of the complex joints can be conveniently and accurately calculated. According to the method, based on a freeze-thaw test and a direct shear testof a joint sample, a shear strength parameter damage evolution model is established; further an improved shear strength calculation formula is derived; according to the calculation formula, the damageaccumulation of freeze-thaw cycle and the influence of joint connectivity are considered at the same time; the degradation characteristics of the coupling effect of the freeze-thaw cycle and the joint connectivity on the shear strength parameters can be deeply analyzed, the high coincidence degree of the calculation result of the improved calculation formula and experimental data is obtained according to the subsequent test result, and the reasonability of the improvement criterion is shown.

The invention provides an I type stress intensity factor test method considering frost heaving force periodic change. The method comprises the following steps: step 1, manufacturing a test piece, andapproximately simulating a crack of a non-through rock mass by using a water knife kerf on the test piece; step 2, vacuumizing and saturating the test piece; step 3, sticking a strain gauge in a non-plastic region range of the tip of the test piece; step 4, putting the test piece into a rock fracture frost heaving test box, pressurizing air bags on the two sides of the frost heaving test box by using a pressurizing device, closing a valve, taking down a pipeline, putting the frost heaving test box filled with the test piece into a water tank, and enabling water to submerge the test piece; andstep 5, putting the water tank and the frost heaving test box into which the test piece is put into a high-low temperature alternating test box together to start a freeze-thaw cycle test. According tothe method, the freezing and thawing state of the non-through fractured rock mass can be truly simulated in the mode that water is effectively blocked when the cracks of the sample are frozen and water is supplemented in time when the cracks of the sample are thawed, so that the freezing and thawing damage result of the fractured rock mass can be accurately represented.

The invention provides a method for obtaining a mesoscopic degradation mechanism of Inan'an rock in a freeze-thaw cycle process, and relates to the technical field of freeze-thaw rock. Based on the microscopic change of rock damage expansion evolution, the development law of microscopic damage damage of rock in freeze-thaw cycle is obtained by a digital image numerical method, and the comprehensive damage law of freeze-thaw British-Ann rock under the action of freeze-thaw cycle load is obtained from the microscopic scale and the macroscopic scale. The method mainly comprises the following steps: establishing a finite element mesh model by using a microstructure image of an Inan'an rock slice; carrying out instantaneous cooling temperature field simulation, stress field freeze-thaw cycle simulation and displacement field freeze-thaw cycle simulation on the finite element mesh model; obtaining a plurality of temperature change distribution diagrams, a plurality of shear stress cloud diagrams, a plurality of tensile stress cloud diagrams and a plurality of displacement vector diagrams, and analyzing the plurality of temperature change distribution diagrams, the plurality of shear stress cloud diagrams, the plurality of tensile stress cloud diagrams and the plurality of displacement vector diagrams to obtain a mesoscopic degradation mechanism of the Inan'an rock slice in the freezing and thawing cycle process.

The invention discloses a preparation method of a 3D-printable high-internal-phase emulsion with high freeze-thaw stability, which comprises the following steps: S1, taking Atlantic cod as a raw material, and extracting an Atlantic cod protein crude extract; S2, dissolving the Atlantic cod protein crude extract in water according to the concentration of 15-50mg/ml, adding glucose, carrying out Maillard reaction at 110-160 DEG C for 15-80 minutes, cooling, dialyzing at 4 DEG C, freeze-drying, and redissolving to obtain a water phase; and S3, taking edible vegetable oil as an oil phase, adding the oil phase into the water phase, and acting for 30-180 seconds by using a homogenizer at the speed of 5000-16000 rpm to form the high internal phase emulsion. The highly inward emulsion prepared by the invention is a colloidal emulsion, has high freeze-thaw stability, and can still maintain a good form after three freeze-thaw cycles. The method is relatively low in cost, simple and convenient to operate, short in period, easy to industrialize and capable of obtaining the high-internal-phase emulsion with relatively high freeze-thaw stability.