45 results about "Mass transfer resistance" patented technology

This application provides a method for preparing ferrocoke using zinc-containing dust and lean coal, belonging to the fields of iron and steel metallurgy and low-carbon ironmaking technology. The method uses zinc-containing dust and lean coal as raw materials, adding 10% medium-temperature coal tar pitch as a binder by weight of the total ferrocoke. During the ferrocoke preparation process, the metallic elements and their oxides in the zinc-containing dust can promote the reaction between carbon and CO2 at high temperatures, making carbon more easily consumed. Simultaneously, Zn volatilizes and migrates under high-temperature reducing conditions, making the local carbon structure loose and gradually forming interconnected pore structures around the dust particles. These pores facilitate the entry of CO2 gas into the ferrocoke to participate in the reaction, while also helping the generated gas to be discharged in a timely manner, thereby reducing mass transfer resistance. Through this effect, not only is the gasification reaction process accelerated, but the overall reaction performance of the ferrocoke is also improved, giving it higher gasification efficiency, making it suitable for blast furnaces, reducing the coke ratio, and improving smelting efficiency.

The utility model relates to the field of cleaning brush, concretely relates to a centrifugal cleaning machine of cleaning brush, is equipped with cleaning room, is equipped with the drive end and water pass end who set up oppositely in the cleaning room, and the both ends of cleaning brush product can be engaged with the drive end and water pass end, and the water flow enters the product inside from the water pass end, and the water flow is thrown to the product outside and flows out through centrifugal rotation mode. Compared with the prior art, the application promotes the water flow to penetrate the complex three-dimensional pore of the sponge body by means of centrifugal force, breaks the mass transfer resistance limit of traditional water washing, realizes the thorough removal of internal residual starch particles, and guarantees cleaning uniformity and thoroughness.

The utility model relates to water electrolysis technical field, specifically disclose a kind of low-temperature full gaseous water vapor electrolytic hydrogen production device and system. The utility model aims at overcoming the limitations of existing water electrolysis technology in energy efficiency, cost, system complexity, operation flexibility and environmental adaptability etc. The utility model is core at, under the mild condition lower than 90 DEG C, water is supplied to cathode and anode of electrolytic cell in the form of pure gaseous water vapor simultaneously, using specially designed membrane electrode assembly and internal water management structure, under the action of direct current, water vapor is decomposed efficiently to generate high-purity hydrogen and oxygen. The entire electrolysis process avoids the direct input and circulation of liquid water, realizes gas-solid two-phase interface reaction, significantly simplifies water balance system, reduces equipment volume and weight, solves the bubble coverage of traditional liquid phase electrolysis, mass transfer resistance. The utility model device has the characteristics of modularization and miniaturization, and significantly reduces the net power consumption per unit hydrogen production.

This invention provides a biomass pretreatment method using a steam-coupling twin-screw extruder, along with cellulose-containing biomass and its applications. The biomass pretreatment method includes the following steps: sequentially subjecting pre-softened biomass raw materials to steam treatment and twin-screw extrusion crushing to obtain biomass particles; the biomass particles are then subjected to a cooking reaction to obtain cellulose-containing biomass. This invention utilizes the synergistic effect of steaming and twin-screw extrusion crushing to overcome the mass transfer resistance of dense wood with low energy consumption, aiming to solve the problems of dense forest biomass structure, high energy consumption in traditional pretreatment methods, and difficulty in chemical penetration. This process can effectively reduce the amount of chemicals used to achieve efficient and directional separation of components, fully adapting to the needs of low-cost, continuous industrial production.

The application discloses an electrochemical acid-base generator, and relates to the technical field of electrochemistry, comprising an anode chamber, a first material chamber, an alkali chamber, a catalytic chamber, an acid chamber, a second material chamber and a cathode chamber; the anode chamber and the first material chamber are separated by a proton exchange membrane; the first material chamber and the alkali chamber are separated by a cation exchange membrane; the alkali chamber and the catalytic chamber are separated by an anion exchange membrane; the catalytic chamber and the acid chamber are separated by a cation exchange membrane; the acid chamber and the second material chamber are separated by an anion exchange membrane; and the second material chamber and the cathode chamber are separated by a proton exchange membrane. The multi-chamber structure optimizes the ion transmission path, significantly reduces the mass transfer resistance, and the special catalytic layer design further improves the hydrolysis reaction efficiency, so that the current density is improved compared with a traditional three-separation-chamber structure, and the production efficiency is improved.

This invention relates to the field of bio-based polyamide synthesis technology and discloses a polycondensation preparation process for high-strength bio-based polyamide denim yarn fibers. The process includes: adding bio-based diacid, diamine, and lignin-derived triamine into a reactor and pre-condensing at 210°C to 230°C to generate oligomers; in the deep polycondensation stage, self-flash disturbance is induced by periodically adjusting the vacuum level to drive the uniform migration of branched modified components; when the stirring torque reaches the preset maximum process torque value, vanillic acid monoester is added for end capping. This invention utilizes pulsed pressure fluctuations to break the mass transfer resistance of the high-viscosity system, ensuring uniform distribution of branched nodes throughout the entire domain. The constructed isotropic topological network is based on the shear-thinning characteristics of the product and forms a three-dimensional stress diffusion system in the fibrous state, improving load transfer efficiency and avoiding the risk of fibrillation in denim fabrics under heavy washing conditions.

The application relates to a composite catalytic system for accelerating hydrogen production by magnesium hydride hydrolysis and a preparation method and application thereof, relates to the technical field of hydrogen production by magnesium hydride hydrolysis, and solves the problem that the existing hydrogen production by magnesium hydride hydrolysis reaction has large mass transfer resistance in the later stage and it is difficult to realize rapid and complete conversion of MgH2 under mild conditions. The composite catalytic system is composed of independently mechanically ball-milled pre-activated magnesium hydride powder and cerium chloride powder. In an inert atmosphere, the magnesium hydride powder is independently mechanically ball-milled for pretreatment to obtain activated magnesium hydride powder; the activated magnesium hydride powder and the cerium chloride powder are uniformly mixed according to a set molar ratio to obtain a cerium-based composite catalytic system. The above cerium-based composite catalytic system is added into water to initiate a hydrolysis reaction for hydrogen production at 20-60 DEG C. The catalytic system can stably meet the rapid gas production demand of a portable hydrogen supply device, has catalytic efficiency and cost advantages, and is suitable for large-scale application in actual scenes.

This invention discloses a method for improving the quality stability of frozen oysters and a frozen oyster meat product, relating to the field of aquatic product processing technology. The method for improving the quality stability of frozen oysters provided by this invention employs ultrasonic treatment combined with citric acid solution soaking. It utilizes the cavitation effect, microjets, and mechanical vibration generated when ultrasound propagates in a liquid medium to effectively disrupt the mass transfer resistance on the surface of oyster tissue, significantly promoting the penetration and uniform distribution of citric acid within the muscle tissue. This solves the problems of low penetration efficiency of active ingredients and insufficient internal tissue protection in traditional citric acid soaking treatments, achieving effective inhibition of lipid and protein oxidation. This invention features a simple process, high safety, requires no complex equipment, and is suitable for large-scale application in the aquatic product processing industry.

This invention proposes a polybenzimidazole microporous ion-conducting membrane and its one-step electrospray preparation method. Polybenzimidazole electrospray solutions are prepared using organic solvents with different boiling points. Electrospray parameters are adjusted under a high-voltage electrostatic field, and the polybenzimidazole electrospray solution is dispersed into nanodroplets using this field. A receiving roller rotates to spread and layer the droplets, followed by rapid drying and solidification, directly preparing the polybenzimidazole microporous membrane. This invention can directly prepare microporous membranes using non-ionic polymer materials, and the membrane preparation process is simple and easily scaled up. It overcomes the problem of high mass transfer resistance of non-ionic polymers, enabling highly selective proton conduction. Simultaneously, the high stability of non-ionic polymers improves the oxidative stability and mechanical strength of the ion-conducting membrane, showing broad application prospects in the field of new energy storage flow batteries.

The application discloses a preparation method of 3,4,5,6-tetrahydrophthalic anhydride by catalytic isomerization, and nitrogen-doped porous carbon is prepared by carbonizing melamine sponge, the nickel is loaded by cooperating with wetting of a surfactant and ultrasonic cavitation, and the loaded nickel catalyst is obtained by roasting and reduction. 1,2,3,6-tetrahydrophthalic anhydride is heated and refluxed in an organic solvent and catalyst to isomerize, the catalyst is recovered by filtration, and the product is obtained by cooling and crystallizing the filtrate. The method utilizes the through macroporous structure to eliminate the mass transfer resistance, and the nitrogen-anchored nickel prevents agglomeration, so that the catalyst is low in cost, recyclable and free of waste water.

The application provides a preparation method of a double-layer hollow fiber membrane, which comprises adding inorganic nanoparticles and foaming particles in an outer layer spinning solution, adding nanosheets in an inner layer spinning solution, and then extruding simultaneously through wet spinning to obtain the double-layer hollow fiber membrane after coagulation. In the application, the inorganic nanoparticles are uniformly dispersed in the outer layer spinning solution to improve the wear resistance of the membrane, the foaming particles, especially the nanoparticles, are added to cooperate with an acidic gel bath to generate nanobubbles, so that the open porosity of the outer layer surface of the membrane is increased, the inner layer membrane is effectively shortened in the transmission path by inserting two-dimensional nanosheets, the mass transfer resistance is reduced, the flux of the double-layer hollow fiber membrane itself is ensured to be high, and the bonding force between the inner layer and the outer layer is improved. The double-layer hollow fiber membrane prepared by the application has the advantages of wear resistance, anti-pollution and difficulty in delamination, while the membrane flux is suitable, and the operation is simple and easy to scale up.

The application discloses a thermogravimetric analysis device and method for high-humidity multi-component atmosphere reaction kinetics research, and belongs to the technical field of thermogravimetric analysis instruments.The device comprises a reaction module, a heating furnace, a weighing module, a gas distribution module and an analysis module; the reaction module is vertically arranged in the heating furnace, and the core is a reaction tube main body which is open at the lower part; the side surface is connected with a gas inlet pipe and a sampling pipe from top to bottom; the weighing module is located below the reaction module and comprises a weighing balance, a water cooling unit and a weighing support rod; the water cooling unit can control the water vapor condensation area and stabilize the balance temperature; the gas distribution module can provide a multi-component reaction atmosphere containing controllable concentration water vapor; and the analysis module can detect the tail gas composition in real time.The application can realize low gas-solid mass transfer resistance, stable control of a high-humidity environment, wide particle size sample measurement and rapid temperature rise and fall, and is suitable for high-humidity multi-component atmosphere gas-solid reaction kinetics research in the fields of combustion, catalysis, adsorption and the like.

The application relates to a distributed sewage treatment facility water quality soft measurement method and system, which comprises the following steps: obtaining an operation electrical signal of a target power equipment in a distributed sewage treatment facility, and analyzing and generating an electrical energy fingerprint data sequence; based on a coupling mechanism of fluid rheology and oxygen mass transfer dynamics, performing decoupling operation on the electrical energy fingerprint data sequence to generate a first physical mechanism feature vector representing fluid physical rheological properties and a second physical mechanism feature vector representing gas-liquid contact surface mass transfer resistance, and then inputting into a preset cross-domain adaptive mapping model for calculation, outputting a target water quality monitoring index, and comparing the target water quality monitoring index with a preset safety threshold to generate an operation and maintenance control instruction for the target power equipment. The application has the advantages that rheology and oxygen mass transfer dynamics characteristics can be separated from the electrical signal, and individual differences of equipment and environmental noise interference can be overcome.

This invention discloses a digital twin control system for an immobilized microbial denitrification process. The system includes: a data synchronization module for collecting data from the immobilized microbial denitrification reactor and generating an operating status sequence according to the same sampling period; and a mass transfer state inversion module for inverting the mass transfer resistance coefficient, effective reaction depth, and clogging risk level by integrating the time delay from influent nitrogen disturbance to effluent nitrogen response, bed pressure difference changes, recovery time after flow disturbance, and dissolved oxygen changes on the ammonia nitrogen removal rate. This invention relates to the field of wastewater treatment technology. This digital twin control system for an immobilized microbial denitrification process, through the mass transfer state inversion module, integrates the time delay from influent nitrogen disturbance to effluent nitrogen response, bed pressure difference changes, and recovery time after flow disturbance to improve the ability to identify hidden states within the immobilized carrier.

The present application relates to the technical field of water quality monitoring, and discloses a water sample pollution inspection method guided by microorganism detection, comprising: applying a pulsed electric field to a biochemical response system to reduce the mass transfer resistance of the cell membrane of an indicator microorganism by using a physical pore-forming effect; injecting a fluorescent substrate and synchronously collecting fluorescence emission intensity and backscattering light intensity; correcting the amplitude of the fluorescence emission intensity by using the backscattering light intensity to eliminate physical shielding interference and obtain a pre-steady-state fluorescence emission sequence; intercepting a characteristic value of the change rate of the pre-steady-state fluorescence emission sequence to calculate an intrinsic catalytic turnover index representing the specific catalytic activity of intracellular enzymes, and determining the pollution degree of the water sample to be tested according to the offset of the index relative to a preset reference value; and the present application can quickly identify pollutants with transmembrane mass transfer disorders and eliminate the influence of endogenous activity fluctuations of microorganisms on the detection result by means of the cooperation of electric pore-forming intervention and calculation logic.

This invention relates to a method for ultrasonic-assisted supercritical CO2 extraction of highly active Torreya grandis oil, comprising the following steps: S1 Raw material preparation: Take dried Torreya grandis kernels (moisture content ≤10%), pulverize them to 80-300 μm under nitrogen protection at -20 to -10℃ to obtain Torreya grandis powder; This invention uses low-temperature nitrogen-protected pulverization, the addition of soybean lecithin and rosmarinic acid compound antioxidants, and ultrasonic-assisted supercritical CO2 periodic pressure swing extraction to synergistically inhibit oil oxidation, resulting in Torreya grandis oil with a peroxide value ≤0.87 mmol / kg, effectively preserving oil activity; The three-stage cyclic pressure swing extraction mode of "low pressure-medium pressure-high pressure" is adopted, combined with the intermittent strengthening effect of bursting ultrasound, periodically changing the pressure inside the extraction vessel, causing repeated compression and expansion of the cell wall, forming "breathing" rupture, significantly reducing mass transfer resistance, and increasing the extraction rate to over 46%.

The application discloses a method for intensively degrading methane by using a peristaltic pump to drive immobilized bacteria, and belongs to the field of environmental biotechnology. The method comprises the following steps: immobilizing methane-oxidizing bacteria on the surface of a porous carrier such as a metal organic framework material, activated carbon or alumina; constructing a closed circulation device composed of a gas storage bag, a peristaltic pump and a culture tube; and intensifying methane mass transfer by using pulsating flow generated by the peristaltic pump. The method overcomes the defects of large gas-liquid mass transfer resistance, easy loss of bacteria and complicated operation in traditional methane-oxidizing bacteria culture. Under the optimal conditions, the methane oxidation rate can reach 12.9 micromoles / h, which is significantly higher than that in static culture.

The application provides a preparation method and application of an ultrathin carbon capture membrane, and the carbon capture membrane is a three-layer composite structure, from top to bottom, which is an interface polymerization PA separation layer with CO2 affinity, a diffusion method ZIF-8 layer and a hydrolysis PAN support layer. The application utilizes interface polymerization to control ZIF-8 and PA self-inhibition growth to form a complete coated ultrathin membrane by a relative diffusion method, develops an integrated reactor without process transfer, ensures that diffusion preparation and interface polymerization occur in the same position, selects an organic solvent to control monomer diffusion and growth rate to avoid pore blockage of porous material growth and growth area deviation of polymers, reduces mass transfer resistance, and selects a reasonable way to treat the support to strengthen the interface bonding between the support and the membrane layer. Meanwhile, the preparation process is simplified, and membrane preparation loss in the reaction process is avoided. The preparation process of the application is simple, easy to realize scale-up preparation, and has excellent CO2 / N2 performance.

The application discloses a preparation method of a composite film, and the method comprises the following steps: S1, performing surface modification treatment on an initial base film to obtain a first base film; S2, performing first contact between the first base film and a first solution and performing first drying to obtain a second base film; and S3, performing second contact between a second solution and the surface of the second base film to obtain the composite film; the first solution comprises acyl chloride and an alkane solvent, the content of the acyl chloride is 0.05-0.4 wt.% based on the total weight of the first solution; the second solution comprises polyether amine and an aqueous solvent, the content of the polyether amine is 0.5-5 wt.% based on the total weight of the second solution; and the temperature of the first drying is 20-75 DEG C. The composite film obtained through the above method has a membrane layer structure with small mass transfer resistance, and simultaneously has excellent gas permeation performance and high gas separation selectivity.

This invention belongs to the field of online analysis and detection, and provides an online analytical material for chlorobenzene impurities and its preparation method. The invention employs a core-shell-skin structure composite particle with zirconium-based metal-organic framework nanocrystals as the core, a covalent organic framework as the shell, and a molecularly imprinted polymer as the skin, synergistically constructing a gradient functional composite coating on a disulfide-bonded dynamic organosilicon network matrix and immobilizing it on a silica carrier. This achieves a synergistic balance between high recognition site density and uniform coatability, high adhesion, wear resistance, erosion resistance, and low mass transfer resistance with rapid response, as well as dynamic self-healing function and long-term structural stability under acid / solvent / thermal-vacuum conditions. It solves the problem of simultaneously improving sensitivity, response speed, repeatability, and service life, and has wide application value in the online analysis of chlorobenzene impurities in petrochemical, fine chemical, and online environmental monitoring fields.

This invention relates to the field of traditional Chinese medicine (TCM) technology, and discloses a TCM composition for treating obesity-related hypertension and its preparation method. The composition is made from white ginseng, gynostemma pentaphyllum, Eucommia ulmoides, kudzu root, Atractylodes macrocephala, hawthorn, Alisma plantago-aquatica, Euonymus alatus, Gastrodia elata, Uncaria rhynchophylla, peppermint, and Rhodiola rosea. The preparation process includes a compound enzymatic hydrolysis pretreatment, utilizing cellulase and pectinase to synergistically disrupt cell walls, combined with dual extraction steps of water extraction and alcohol extraction to selectively dissolve components of different polarities. Pharmaceutical excipients are then added to prepare concentrated pills, granules, or tablets. This composition has the effects of invigorating the spleen and replenishing qi, resolving phlegm and eliminating turbidity, and calming the liver and suppressing yang. Through multi-target synergistic action, it achieves simultaneous intervention on blood pressure levels and lipid metabolism, effectively improving metabolic abnormalities in obese patients. The process of this invention reduces mass transfer resistance, increases the transfer rate of total saponins and flavonoids, and results in a product with uniform and stable quality, suitable for large-scale production.

This invention relates to a microencapsulated denitrifying bacterial agent and its preparation method. Specifically, this invention provides a microencapsulated denitrifying bacterial agent employing an asymmetric double-layer wall structure. The inner wall material is a composite system of low-concentration sodium alginate and a mass transfer enhancer, while the outer wall material is a composite system of high-concentration sodium alginate and chitosan, prepared through a stepwise cross-linking process. By constructing a double-layer wall structure combining an inner low-concentration mass transfer optimization layer and an outer high-concentration mechanical protection layer, and by precisely controlling the concentration ratio of each wall material, the concentration of the cross-linking agent, and the cross-linking time, the technical contradiction of balancing mass transfer resistance and mechanical strength in existing microencapsulated wall materials is effectively solved. This achieves a significant reduction in wall material mass transfer resistance and an improvement in denitrification efficiency (ammonia nitrogen removal rate ≥90%, total nitrogen removal rate ≥85%) while maintaining high encapsulation efficiency (≥85%) and good mechanical strength. It can be widely used in wastewater treatment, aquatic ecological restoration, and other fields.

The present application relates to the technical field of petroleum chemical industry, in particular to modified needle coke based on ethylene tar and its preparation method and application. The method mixes refined ethylene tar, modified graphene oxide and boron-containing pore-forming microspheres, and cokes under pressure; after coking, pressure is released and cooled, and the obtained mesophase coke is transferred to a high-temperature furnace for high-temperature calcination, and internal pores are constructed by the gasification and escape of zinc components; and the modified needle coke is obtained by acid washing and impurity removal. The present application forms abundant mesoporous structures by pressure release and pore formation, which is beneficial to the diffusion of macromolecules and can reduce the diffusion mass transfer resistance of macromolecules; the doped heteroatom sites in the carbon skeleton can enhance the interaction between the carrier and the active metal precursor, and improve the dispersion of the hydrogenation active metal.

This invention belongs to the field of catalysts and organic synthesis, specifically relating to a surface-modified lipophilic catalyst and its application in the preparation of bis-ethylhexyloxyphenol methoxyphenyl triazine. This invention utilizes lipophilic modification to construct lipophilic channels, significantly reducing mass transfer resistance and allowing sterically hindered phenolic ethers to rapidly enter the active site, resulting in a more complete reaction. Zinc ions and sulfonic acid groups form a dual-acid synergistic catalysis, providing mild activation, high selectivity, and suppressing side reactions. The ionic liquid and ethanol form a polar gradient field, achieving directional substrate delivery, intermediate stability, and rapid product desorption. Catalyst regeneration is simple; it can be reused after washing with anhydrous ethanol, eliminating the need for brine and hydrochloric acid and preventing secondary pollution.

This invention discloses a method for preparing metal-doped hierarchical porous carbon for co-adsorption of multiple VOCs. The method employs a low-cost carbon precursor and constructs a well-developed microporous-mesoporous / macroporous hierarchical pore structure using a chemical / catalytic gradient activation method. Trace metal adsorption sites are dispersed / doped through liquid-phase impregnation / low-temperature fixation. This invention utilizes the mass transfer channel effect and hierarchical storage mechanism of the hierarchical porous carbon support to rapidly and cost-effectively dope metal adsorption sites for the efficient treatment of multiple VOCs in industrial flue gas. It solves the problems of traditional microporous carbon adsorbents, which suffer from limited pore structure, lack of selective adsorption sites for small-molecule polar VOCs, and difficulty in effectively co-adsorbing VOCs with different physicochemical properties in industrial flue gas. Furthermore, it addresses the issues of micropore blockage due to doping, excessive mass transfer resistance, and low accessibility to deep pores and adsorption sites. This provides a new approach for the development and application of VOCs co-adsorption materials.

This application relates to the technical field of distillation and purification equipment, and discloses an electronic-grade trichloroethylene purification production apparatus, including a distillation column. The distillation column has multiple longitudinally equidistantly arranged trays fixed inside. Several overflow frames are fixedly installed on the top of the trays, and a guide plate is fixedly installed at the bottom of the trays directly below the overflow frames. Gas guide pipes are fixedly installed on both sides of the bottom of the trays, and several gas guide grooves are opened on both sides of the gas guide pipes. The vapor flowing out through the gas guide pipes forms a cross-shaped contact mass transfer with the liquid film flowing vertically downwards along the guide plate. The cross-shaped flow generates high-frequency turbulent disturbances, causing continuous breakage and recombination of the gas-liquid interface, significantly shortening the mass transfer boundary layer thickness, reducing mass transfer resistance, and allowing for faster heat exchange after the liquid film is cut into a thin layer by the gas flow, reducing the risk of decomposition due to localized overheating. This apparatus is suitable for the high-efficiency distillation and purification of trichloroethylene.

The utility model discloses a kind of based on temperature-sensitive control's tea enzymatic supercritical fluid extraction device, including bottom plate, the top of bottom plate is fixedly installed with mounting seat, the top of mounting seat is fixedly installed with enzymatic component, the inside of enzymatic component is installed with stirring component, the other end of bottom plate top is fixedly installed with extraction component, and one end of extraction component is fixedly communicated with separation collection component, a kind of based on temperature-sensitive control's tea enzymatic supercritical fluid extraction device of the utility model, by the pretreatment of the enzymatic method to the tea that needs extraction, target component in tea cell is more easily released into solution, and enzyme can degrade macromolecule combined with target component, reduce impurity adsorption in extraction process, improve the free rate of target component, and by the cooperation of enzymatic and supercritical fluid extraction, enzymatic pretreatment makes target component fully release from matrix, reduce mass transfer resistance, supercritical fluid can quickly diffuse and dissolve target component, shorten extraction time.

This invention utilizes waste coffee grounds to successfully prepare a high-performance carbon capture material through a combination of cold pressing and high-temperature co-sintering processes. Its core lies in a "triple synergistic enhancement" mechanism: biomass burn-off forms a hierarchical macroporous network, reducing mass transfer resistance; potassium in the ash is used for in-situ doping, promoting ion diffusion; and carbothermic reduction generates oxygen vacancies, enhancing CO2 adsorption capacity. This material exhibits high adsorption capacity, excellent cycling stability, and good mechanical strength at high temperatures, providing a green technological path for low-cost, industrial-scale production of carbon capture materials.