827 results about "Volatile substance" patented technology

The present application relates to the technical field of back contact cells, and in particular to a back contact cell and a manufacturing method therefor. The back contact cell comprises a silicon wafer, a first semiconductor layer, a second semiconductor layer, and a conductive film layer, wherein isolation grooves are formed in the conductive film layer. The back contact cell further comprises a plurality of insulating ink layers which are all disposed between the second semiconductor layer and the conductive film layer and arranged at intervals along a back surface in an X-axis direction, wherein the insulating ink layers are in direct contact with the second semiconductor layer, and in the X-axis direction, the insulating ink layers stretch across the edges of the side surfaces of second semiconductor opening regions and each have two ends extending respectively. The insulating ink layer satisfies the following conditions: the surface pencil hardness is not less than 2H, the resistivity is greater than 1e11Ω·cm, and the mass content of volatile substances in raw materials of the insulating ink layer is not greater than 5%. The present application can effectively avoid electric leakage and improve the cell conversion efficiency and the cell yield, and the technological process of manufacturing is simpler.

The present application discloses a continuous dynamic and efficient devolatilization method for a polymer / volatile system based on high mass transfer interfaces, including the following steps: providing a dynamic single-screw devolatilizer, feeding a polymer solution to the devolatilizer, wherein the polymer solution includes polymer and volatile substances with small molecule weight, and the volatile substances include organic solvents, residual monomers, water or reaction by-products; conveying and compressing polymer materials by the screw downstream a devolatilization section, and extruding the polymer materials out of the dynamic single-screw devolatilizer directly; or providing a side-feeding extruder downstream of the devolatilization section and feeding plastic additives into a devolatilized polymer melt, and then melt blending the plastic additives with the devolatilized polymer melt at an end of the dynamic single-screw devolatilizer before exiting the dynamic single-screw devolatilizer.

The invention relates to the technical field of tourism services, in particular to a grease detection device and method for edible oil production and processing, and a system comprises a spectral data acquisition module, a component ratio calculation module, a spectral feature analysis module, a chemical component deviation evaluation module and a smell component fluctuation detection module. According to the method, accurate identification of edible oil component characteristics is improved by using the laser Raman spectrometer, fine analysis of complex components is realized by combining gas and liquid chromatograms and mass spectrometers, release of volatile substances is monitored by the electronic nose sensor, and environmental adaptability and dynamic response capability of data are enhanced. Through automatic abnormal data elimination and normalization processing, the data consistency and standardization level are improved, the accuracy of sample classification and edible oil safety assessment is further improved through multi-parameter ratio calculation and peak position offset analysis, the data processing flow is optimized, automation and intelligence of the detection system are enhanced, and the detection efficiency is improved. And the efficiency and the precision of edible oil detection are obviously improved.

The present invention relates to gas detection devices, and in particular to volatile substance sensors, such as respiratory alcohol device sensors. A semiconductor gas sensor device according to the present invention includes a laser structure and an optical waveguide resonator formed in the same compound semiconductor including at least one light emission layer and one light propagation layer. The optical waveguide resonator is formed in the light propagating layer, and a majority thereof is separated from a remainder of the light propagating layer. The laser structure is disposed adjacent a portion of the optical waveguide resonator and is arranged to transmit electromagnetic radiation of a particular wavelength band to the optical waveguide resonator arranged to resonate at the particular wavelength band.

The invention discloses a switchable graded sampling pre-construction control method for dust and a detection device. The method comprises the following steps: synchronously acquiring data through multiple types of sensors, constructing a condensation risk prediction model, calculating a condensation risk index RI and dividing risk grades; based on the risk level, dynamically adjusting the target power of the heating wire, the blowback period of the air pump and the airflow speed, and cooperatively triggering an electrode cleaning and trapping filter screen switching program; after cleaning is completed, follow-up control parameters are dynamically adjusted; and closed-loop control is formed. According to the method, the temperature and humidity sensor is arranged in the external environment to obtain background parameters, the airflow velocity sensor is used for sensing the working condition change of the air pump, and a dynamic condensation risk prediction model is established, so that excessive heating is avoided fundamentally, and evaporation loss of semi-volatile substances is prevented; therefore, the accuracy of a dust concentration detection result is remarkably improved in an extreme humidity environment.

The invention provides a polymer carrier capable of wrapping volatile substances or functional active substances. The invention further provides a method for wrapping the volatile substance or the functional active matter with the polymer carrier. The invention further provides application of the polymer carrier in cosmetics. The invention also provides a method for increasing the residence of volatile substances or functional active substances on the skin by using the polymer carrier. The invention further provides a cosmetic and application thereof. According to the method for increasing residence of the volatile substances or the functional active substances on the skin through the polymer carrier, the operation method is simple and controllable, the product is stable, the process reproducibility is high, the content of the active substances is controllable, the volatilization loss of the active substances is reduced, and the residence amount of the active substances is remarkably increased.

A coke product configured to be used in foundry cupolas to melt iron and produce cast iron products is disclosed herein. In some embodiments, the coke product has a Coke Reactivity Index (CRI) of at least 30% and an ash fusion temperature (A FT) less than 1316° C. Additionally or alternatively, the coke product can comprise a fixed carbon content of at least 80% and / or a volatile matter content of no more than 1.0%.

Provided are processes for development of photopatterned metal or metal oxide-based thin film photoresists post-EUV exposure for removal of non-volatile species and deterring etch stop. Repeated cycles of alternating treatment with an etchant and an oxidizing agent; or treatment with an etchant followed by treatment with a wash agent are effective techniques for removal of the undesired unexposed portion of a photoresist.

The invention relates to the technical field of semiconductor gas sensors for gas detection, in particular to an in-situ construction method and application of a gas sensor for volatile aroma substance detection, and the in-situ construction method comprises the following steps: mixing an aqueous solution of zinc nitrate hexahydrate and an aqueous solution of 2-methylimidazole according to different molar ratios to obtain a precursor solution; upwards fixing a planar electrode on the surface of a glass slide, and then transferring the planar electrode into the precursor solution; carrying out hydrothermal reaction on the precursor solution at 90 DEG C for 4 hours, after the hydrothermal reaction is finished, cooling to normal temperature, taking out the glass slide, washing the surface of an electrode by using deionized water, removing impurities, and then carrying out drying treatment; calcining the obtained dried electrode in an air atmosphere at 500 DEG C for 2 hours to construct an in-situ growth semiconductor sensor; according to the present invention, the rapid sensing response on nine volatile aroma substances is achieved, and the excellent gas sensitive characteristic is represented in the gas sensitive research on the volatile substance ocimene in the volatile aroma substances.

The invention provides a preparation method for improving EGCG content of tea tree fresh leaves, which specifically comprises the following steps: spraying a mixed solution of salicylic acid and methyl jasmonate on new shoot leaves of a current year of tea tree, and picking 48 hours after spraying, so as to obtain the tea tree fresh leaves with high EGCG content, increase the volatile substance content of the tea tree, and improve the EGCG content of the tea tree fresh leaves. The growth of the tea trees can be promoted.

The invention relates to the field of environmental monitoring, and discloses a system for collecting and preprocessing a volatile organic compound sample in water based on a headspace principle, which constructs a full-automatic physical execution chain through multi-thread interrupt control, PID closed-loop regulation and a mechanical arm state machine. Comprising the following steps: constructing a pre-packaged intelligent sample bottle, encrypting and storing a freeze-dried internal standard substance, a sealing parameter and a calibration curve in a UHF RFID tag, and eliminating the risk of manual intervention; on the basis of a multi-thread parallel control technology, constant-speed sampling, three-stage gradient filtering and environmental parameter binding are synchronously executed, and full-process automation of data acquisition is realized; a physical model is adopted to drive a state machine, balance time is dynamically calculated through a Henry constant, and nitrogen purging pressure closed-loop control is combined, so that the recovery rate of low-volatile substances is increased; a quantum random number generator and a topological data association technology are utilized to construct a structured data packet containing a timestamp, an environment parameter and a quantum check code, and it is ensured that data cannot be tampered.

The invention belongs to the technical field of food flavor engineering, and discloses a Maotai-flavor Baijiu flavor composite essence based on a non-volatile substance release promoting effect, and the composite essence is composed of a volatile aroma substance, a non-volatile organic acid and an amino acid. Aiming at the technical bottlenecks of rapid attenuation of aroma intensity of volatile components and single flavor dimension in the existing Maotai-flavor Baijiu flavor compound essence blending technology, the invention creatively constructs a molecular synergistic system of volatile and non-volatile flavor components. By adding non-volatile substances, the effect of enhancing the flavor of the Maotai-flavor Baijiu flavor composite essence is achieved. The technology not only completely reproduces the flavor structure of the traditional solid-state fermented Maotai-flavor liquor, but also endows the compound liquor and flavor foods (such as Maotai-flavor baked products, compound seasonings and non-alcohol ready-to-drink beverages) with a continuous and stable aroma releasing characteristic, and provides a molecular-level regulation and control scheme for upgrading the sensory quality of liquor flavor standardization and food industrial production.

The invention relates to the technical field of microorganisms, in particular to saccharomyces cerevisiae CEC NW94 and application thereof. The invention provides the Saccharomyces cerevisiae CEC NW94, and the Saccharomyces cerevisiae CEC NW94 is used for brewing the wine, so that the contents of glycerol and lactic acid can be increased, and the yield of volatile acid can be reduced; the synthesis of volatile substances such as ethyl 2-methylbutyrate, isoamyl alcohol and linalool is promoted, and the generation of acetic acid is inhibited, so that the wine presents complex aroma of black fruits, mushrooms and the like, and the odor of herbaceous plants, herbal medicines, vinegar and the like is effectively reduced; in addition, the strain can improve the umami of the grape wine, and improve the aroma purity, the aroma concentration, the wine body, the aftertaste and the complexity. According to the method, the flavor substances of the dry red wine are controlled through a microbial metabolism regulation and control technology, and a new technical scheme is provided for high-quality wine production.

The invention belongs to the technical field of bioengineering, and particularly relates to an application of EcorOBP7 in combination with odor information molecules, and the nucleotide sequence of the EcorOBP7 is as shown in SEQ ID NO.1; the odor information molecules comprise at least one of (E)-beta-farnesene, (E)-beta-myrcene, 3-methylbutyraldehyde, (Z)-beta-ocimene, linalool and cis-acetamino acetate. The odor information molecules are used for detecting the odor of the odor information molecules, and the odor information molecules comprise at least one of (E)-beta-farnesene and (E)-beta-myrcene. The invention finds that EcorOBP7 is a broad-spectrum binding protein, can interact with various information molecules, and can be strongly bound with substances such as (E)-beta-farnesene and cis-acetamido acetate, so that EcorOBP7 can sense odor molecules in the environment through EcorOBP7 highly expressed on antennas of EcorOBP7. Female insects can find proper hosts and spawning sites by distinguishing volatile substances of plants, male insects can find the female insects for mating through perceptual pheromones, and it is indicated that the protein can adjust the foraging and spawning behaviors of eutrophus maculans.

The invention relates to the technical field of aquatic animal living body transportation, and discloses a sea urchin long-distance transportation synergistic method based on dry transportation and anhydrous volatile anesthesia, which comprises the following steps: placing sea urchin in a closed container, using a natural volatile substance as an anesthetic, loading and volatilizing through an adsorption material, and performing anhydrous anesthesia on the sea urchin; the anesthetized sea urchin is inversely placed on a fixing support with a mesh structure in a transportation container in the posture that the mouth face faces upwards and the thorns face downwards, and the sea urchin is prevented from rolling over in the transportation process through the self-locking effect of the thorns and meshes; a functional interlayer is arranged in the fixing support, and a temperature control material and a moisturizing material are placed in the functional interlayer at the same time to maintain the temperature and humidity of the transportation environment; after transportation, the sea urchins are placed in seawater containing the cactus extract for initial recovery and then transferred to flowing natural seawater to complete unified recovery, a whole-process collaborative protection chain of anhydrous anesthesia loss prevention, dry transportation steady state maintenance and rapid water phase restoration can be constructed, and the dry transportation survival rate and quality are remarkably improved.

A method is presented for determining a likelihood of an ignition hazard. The method comprises receiving a current waveform for a lightning strike event at a conductive member that forms an interface with a decomposable member. Material parameter inputs for the conductive member and the decomposable member are received. Based at least on one or more of the received material parameter inputs and an energy from the current waveform, a heating of the decomposable member is resolved, and a quantity of volatiles within the interface volume are determined. A total pressure generation within the interface volume is determined. A probability of ignition hazard by the lightning strike event is output based on a comparison of the total pressure generation and a containment pressure threshold for the interface volume.

The invention discloses an enrichment treatment device for fluorosulfide in a water body, and belongs to the technical field of water sample detection devices. The device provided by the invention can be suitable for sample collection and enrichment of water bodies in different environments such as rivers, lakes, seas and the like; through the adaptation of different pipelines, the device can be combined with an external gas chromatograph for use, so that the enrichment and treatment of trace volatile substances such as trace sulfur hexafluoride and trifluoromethyl sulfur pentafluoride in an environmental water body are realized; according to the device disclosed by the invention, the change of a flow path is realized by switching different valves, the device can realize the enrichment of a water sample in a target concentration range of 10 <-15 >-10 <-9 > mol / L, the enrichment of a trace target object to a trace target object is realized, and the sampling volume can be flexibly adjusted according to actual requirements. The device is simple in structure, convenient to operate and high in adaptability, can meet the detection requirements of different experimental platforms such as ashore and ship, and meets the requirements of different concentration ranges.

The device for evaporating volatile substances comprises a container (1) housing a liquid with volatile substances provided with a mouth (2), a closure assembly (5, 6) placed around the mouth (2) of the container (1), a stopper (3) placed in the mouth (2) of the container (1); and wherein at least a portion of the closure assembly (5, 6) is movable between a first and second positions, wherein in the first position, the closure assembly (5, 6) is disengaged from the stopper (3), and in the second position, the closure assembly (5, 6) is engaged to the stopper (3).It provides a device that allows the container to be filled with a liquid, allowing the wick and the cap to be easily removed and, at the same time, making it safe to use, preventing accidental spillage of the liquid inside the container.

The invention discloses a soybean germplasm resource viability small sample classification prediction method, system and device, and relates to the technical field of soybean germplasm resource viability classification, and the method comprises the steps: obtaining a multi-modal data set of sample soybean germplasm resources; the multi-modal data set is preprocessed; based on the preprocessed multi-modal data set, training a soybean germplasm small sample viability detection model to obtain a soybean seed viability detection model; hyperspectral data and volatilization data of the soybean seeds to be detected are obtained, the soybean seed viability detection model is used for carrying out viability detection on the soybean seeds to be detected, and the viability detection result of the soybean seeds to be detected is obtained. According to the method, the hyperspectral data and the volatilization data of the soybean seeds to be detected are integrated, and the internal chemical characteristics and the volatile substances released from the outside of the soybean seeds are comprehensively considered, so that the vitality of the soybean seeds is more comprehensively and accurately evaluated.

The present invention relates to the technical field of physiotherapy equipment, and particularly to an infrared pulsating moxibustion instrument, which includes an installation box, a connecting arm and a physiotherapy lamp. The connecting arm is rotatably connected to the installation box, and the physiotherapy lamp is rotatably connected to the connecting arm. The physiotherapy lamp includes a housing, a moxibustion unit, a circulation mechanism and a heat insulation net. The housing is fixedly connected to the connecting arm, the moxibustion unit is arranged in the housing, the circulation mechanism is arranged in the housing and is in transmission connection with the moxibustion unit, and the heat insulation net is connected to the bottom of the housing. The purpose is: during moxibustion treatment, the volatile substances generated by the combustion of moxa wool are combined with infrared irradiation treatment to treat the part to be physiotherapied. There is no need to use the heat generated by the combustion of moxa wool. The whole device is simple to operate, smokeless, non-burning and has no side effects, and it is convenient to process the heated moxa wool, which is simple and convenient.

A system and method for a conversion of plastic and carbon feedstock resulting in a hybrid morphology of carbon nanotubes is provided herein. The system includes a feedstock containing a plastic, a conductive carbon, and a metal-based catalyst. The system further includes a plurality of graphite electrodes configured to conduct a current through the feedstock. The system further includes a reservoir configured to contain the feedstock while allowing outgassing during the conversion. The system further includes a chamber configured to contain combustible volatile substances. The system further includes a power source configured to provide electrical power for the conversion. The system further includes an electrical controller configured to use a feedback mechanism for controlling the conversion and growth of the carbon nanotubes.

The invention relates to the technical field of preparation processes, and discloses ancient Huangtai liquor, which is prepared from the following components in percentage by weight: 50 to 55 percent of base liquor, 10 to 15 percent of medicinal and edible traditional Chinese medicinal material extract, 2 to 4 percent of honey, 0.1 to 2 percent of flavor regulator and the balance of purified water, the medicinal and edible traditional Chinese medicinal materials comprise at least one of angelica sinensis, lily, radix ophiopogonis, Chinese dates, Chinese wolfberry fruits, American ginseng, rhizoma polygonati, papayas, astragalus membranaceus and poria cocos, and the liqueur is prepared through the processes of stepped extraction, compound blending, ultrasonic-assisted homogenization, dynamic ageing and membrane filtration. According to the invention, through a stepped extraction process, temperature and time are regulated and controlled in stages, volatile components are preferentially extracted at low temperature, and then non-volatile substances are extracted at medium temperature, so that effective components in the traditional Chinese medicinal materials are fully extracted, the natural flavor of the traditional Chinese medicinal materials is retained, the extraction rate of the effective components is improved, and the flavor level of the liqueur is enriched.

The utility model discloses a cover plate device of a waste collecting box, which comprises a discharge pipe and the waste collecting box arranged below the discharge pipe, and is characterized by further comprising hydraulic cylinders arranged on two sides of the discharge pipe, a box cover is arranged between the discharge pipe and the waste collecting box, a cylinder body of each hydraulic cylinder is fixed with the outer wall of the discharge pipe, and the hydraulic cylinders are fixed on the outer wall of the discharge pipe. The telescopic end of the hydraulic cylinder is fixed to a lantern ring, a shaft rod is sleeved with the lantern ring, the two ends of the shaft rod are fixed to the top of a box cover through side plates, and the box cover is movably buckled to the top of the waste collecting box; a through hole is formed in the top of the box cover and corresponds to an outlet of the discharging pipe, a connecting pipe is communicated with the through hole, and sealing cloth is fixed between the top end of the connecting pipe and the outer wall of the discharging pipe. The tar residue discharging device has the advantages that when tar residues are discharged, the box cover covers the top of the waste collecting box, dust and volatile substances are prevented from leaking out, and environmental pollution is reduced; when the waste collecting box is replaced and moved, the hydraulic cylinder drives the box cover to ascend and descend, leaving of the waste collecting box is not interfered, the box cover is provided with a slightly-adjusted gap, and the situation that the box cover is not tight is avoided.

The utility model discloses a fin type multi-effect evaporation and concentration device, which comprises a first-effect evaporation and separation device, a second-effect evaporation and separation device, a third-effect evaporation and separation device and a fourth-effect evaporation and separation device, wherein the first-effect evaporation and separation device is used for heating liquid feed to evaporation temperature to evaporate volatile substances so as to realize separation and obtain primary feed; the first-effect fin type heat exchanger is used for evaporation and compression; the second-effect evaporation and separation device is used for further evaporating and separating the vaporized liquid; a coil heat exchanger for evaporation and compression is arranged; and the matching device is used for controlling the first-effect evaporation separation device and the second-effect evaporation separation device. According to the utility model, the spiral plate type heat exchanger is arranged in the heater to collect residual steam of fresh steam in evaporation and concentration, and the heat of the residual steam is used for heating feed liquid, so that the heat exchange efficiency is improved.

The invention relates to the technical field of Panax notoginseng planting, and in particular to the application of camphene in promoting the germination of Panax notoginseng seeds and the growth of seedlings. The invention can increase the seed germination rate of Panax notoginseng by fumigating the soil for planting Panax notoginseng with camphene, a volatile substance, and then planting Panax notoginseng seeds on the soil fumigated with camphene, thereby helping the Panax notoginseng seedlings to increase biomass, increasing the above-ground development of Panax notoginseng, promoting the extension of the roots of Panax notoginseng, facilitating the absorption of soil nutrients by Panax notoginseng, and having a significant promoting effect on the germination of Panax notoginseng seeds and the growth of seedlings.

The invention discloses a strain of saccharomyces cerevisiae CPJ-02 with high acid resistance, high ethanol content and strong ester aroma generation and application of the saccharomyces cerevisiae CPJ-02, the strain of the saccharomyces cerevisiae CPJ-02 has been preserved in China Center for Type Culture Collection on June 27, 2024; the preservation number of the strain is CCTCC NO: M 20241388. The saccharomyces cerevisiae CPJ-02 strain is milky white to faint yellow after being cultured on a YPD solid plate for 48 hours, the surface is dry and matte, the texture is slightly rough, and the colonial morphology is round. The saccharomyces cerevisiae CPJ-02 strain has prominent high ethanol tolerance, and still has activity greater than or equal to 92% in a 12% ethanol environment; and the fermentation product is rich in aroma and high in ethyl caprylate and phenethyl alcohol content, more than or equal to 25 volatile substances are detected by GC-MS (gas chromatography-mass spectrometry), and the fermented product is rich in fruit fragrance and has ester flower fragrance. The saccharomyces cerevisiae CPJ-02 strain is suitable for production of high-concentration wines and directional production of low-concentration healthy fermented beverages, fermented foods and aroma compounds.

The invention discloses an application of a volatile substance in prevention and control of agricultural insect chilo suppressalis, and provides an application of (E)-2-hexenal (trans-2-hexenal) in prevention and control of chilo suppressalis for the first time, so that chilo suppressalis adults can be effectively repelled, the egg laying amount of chilo suppressalis female insects can be inhibited, and the prevention and control of chilo suppressalis can be realized. The natural enemy insects attracting the chilo suppressalis comprise egg parasitic wasp trichogramma japonicum and larva parasitic wasp cotesia chilo suppressalis. The (E)-2-hexenal can reduce the egg quantity of chilo suppressalis in the field, reduce the occurrence cardinal number of the chilo suppressalis, play a prevention and control role and reduce loss before pests cause harm, and meanwhile, the (E)-2-hexenal can attract natural enemy insects of the chilo suppressalis, so that natural enemies in the natural environment can be fully utilized and protected, and the economic benefit of the chilo suppressalis is improved. The improvement of the chilo suppressalis prevention and control effect and the green prevention and control are realized. (E)-2-hexenal is a component in rice volatile matters, and compared with chemical pesticides, (E)-2-hexenal is more beneficial to the ecological environment.

The invention relates to the technical field of light vehicle pollutant detection, in particular to a system for testing volatile organic compounds generated during operation of a light vehicle based on a rotating hub closed chamber, and the system comprises a whole vehicle emission sampling unit which is used for simulating a target working condition environment of a target vehicle in a closed space environment, gas containing volatile organic compounds is generated in the operation process of the target vehicle in the target working condition environment; the collecting unit is used for filtering and condensing the gas containing the volatile organic compounds output by the whole vehicle emission sampling unit, and collecting the filtered and condensed gas to obtain a gas sample; and the analysis unit is used for analyzing the gas sample collected by the collection unit and determining the test result of the volatile organic compounds of the target vehicle according to the analysis result of the gas sample. The technology can be used for analyzing the emission characteristics of volatile organic compounds generated in the running process of the light vehicle.

The invention relates to a device for dispensing volatile substances, having a housing (2), a container (5) for the substance to be dispensed, a wick received in the container (5) and protruding from the container (5) with a wick end (6) forming a substance dispensing area, and further having an electrical heating device (8) which has an electrical heating circuit, the heating device (8) being displaceable relative to the wick end (6) in order to set a substance delivery rate. According to the invention the electrical heating circuit of the heating device (8) comprises a thermoswitch (16) being openable by heat exposure at a predetermined switching temperature and being arranged at a distance from the wick end (6), the thermoswitch (16) being switchable as a function of the distance between the heating device (8) and the thermoswitch (16).

The invention discloses a control system of a device for drying metal powder containing combustible volatile substances, and belongs to the technical field of automatic control. In the system, a first subtracter generates a sequence first error signal according to the weight of two pieces of metal powder provided by a weighing sensor at an interval of a time step length; the second subtracter generates a sequence second error signal according to the actually measured temperature and the set temperature in the drying cavity provided by the temperature sensor; the reinforcement learning module respectively generates a first state and a second state according to the sequence first error signal and the sequence second error signal, and generates a control strategy of a PID controller for controlling the working state of the heater according to the first state and the second state; and the fire detection model estimates the probability value of the fire in the drying cavity according to the oxygen concentration in the drying cavity, the concentration of the volatile matter and the actually measured temperature, and if the probability value exceeds a threshold value, the stored inert gas is injected into the drying cavity to reduce the probability of the fire. The explosion risk caused by combustible gas accumulation is avoided.