61results about How to "Eliminate generation" patented technology

The invention discloses a high-performance heat-treatment-free recoverable gravity or low-pressure casting aluminum alloy and a manufacturing method thereof. The aluminum alloy comprises the following elements in percentage by mass: 3-10wt% of Zn; 0.25 to 3 wt% of Mg; 0.5 to 3 wt% of Ca; si: 0.05 to 2 wt%; fe: 0.05 to 2 wt%; not more than 0.15 wt% of unavoidable inclusions; and the balance of Al; the gravity / low-pressure casting as-cast state yield strength of the alloy is larger than or equal to 210 MPa, the tensile strength is larger than or equal to 280 MPa, the ductility is larger than or equal to 5%, the mechanical property of an industrial A356 cast aluminum alloy T6 in a heat treatment state is achieved, high-performance components can be manufactured without heat treatment, energy conservation and cost reduction benefits are remarkable, meanwhile, the alloy has the high-speed rail tolerance limit and recoverability, and the production cost is reduced. And the method has a huge application prospect in lightweight, green and low-cost manufacturing of key structural parts in the fields of automobiles and aviation.

The application discloses a method for modifying and adjusting hot-state desulfurization slag of steelmaking, which comprises the following steps: mixing hot-state molten desulfurization slag and casting residue or mixed liquid casting residue in a hot-state adjusting and conditioning pool, and changing the caking and difficult-to-handle characteristics of the molten desulfurization slag into easy-to-handle modified slag for subsequent disposal. The application solves the technical problem of large lumps of slag and iron in existing steel enterprises, and has strong operability and no safety problem.

A video transmission device 11 includes a plurality of transmission units 112 that each convert into IP packets in parallel each video data with a low frame rate obtained by dividing video data with a high frame rate through allocation in units of video frames in temporally preceding order and transmit the IP packets.

The invention relates to the technical field of cells, in particular to a solar cell and a preparation method thereof, and the preparation method comprises the following steps: adding a hole transport material and a first perovskite material into a solvent to prepare a mixed solution; coating a substrate with the mixed solution, and performing annealing treatment to obtain a composite hole transport layer; coating the composite hole transport layer with a perovskite precursor solution, and performing annealing treatment to obtain a perovskite layer; the perovskite precursor solution comprises a second perovskite material, and the second perovskite material is the same as the first perovskite material. According to the preparation method of the solar cell provided by the invention, the perovskite seed crystal with the same components as the perovskite layer is pre-buried in the composite hole transport layer, and the perovskite seed crystal is used as a nucleation site to induce the perovskite layer to crystallize from bottom to top, so that the generation of bottom holes is inhibited.

The invention discloses a horizontal continuous casting crystallization cavity low-oxygen copper liquid bubble eliminating method and device, and relates to the technical field of low-oxygen copper liquid continuous casting crystallization, a continuous casting machine shell and a bubble eliminating cavity are included, a continuous casting crystallization mechanism is arranged in the continuous casting machine shell, and a stirring mechanism is arranged in the bubble eliminating cavity. The stirring mechanism comprises a first motor arranged in the bubble eliminating cavity, a sliding groove is formed in the first motor, a sliding block is slidably connected to the interior of the sliding groove, a threaded rod is arranged at the output end of the first motor, a threaded cylinder is in threaded connection to the exterior of the threaded rod, and an air suction cylinder is fixedly connected to the interior of the bubble eliminating cavity. The thorn-shaped stirring fan can stir copper liquid in the bubble eliminating cavity at different heights, so that bubbles in the copper liquid are punctured and eliminated, dead angles are few when the bubbles are eliminated, a vacuum environment is formed in the bubble eliminating cavity, some missing bubbles are eliminated again, and the bubbles can be effectively prevented from being generated again in the copper liquid.

The invention discloses a 125-degree PVC energy storage cable material and a preparation method thereof. The 125-degree PVC energy storage cable material comprises polyvinyl chloride resin, a plasticizer, a stabilizer, a lubricant, a flame retardant, an inorganic filler, a scraping and grinding agent, soybean oil and argil. In order to solve the problems that an irradiation crosslinking low-smoke halogen-free material is long in delivery time, not resistant to scraping, unstable in physical performance and wire diameter and high in production cost, the invention provides the 125-DEG C PVC energy storage cable material and the preparation method, the PVC energy storage cable material guarantees the stable physical performance, improves the weather resistance of the cable material, is more resistant to scraping, and is suitable for industrial production. The preparation method provided by the invention has good processability, does not need irradiation, saves time and production cost, and improves production efficiency.

The invention relates to a soil improvement curing agent special for ardealite curing and application, and belongs to the technical field of soil improvement, and the soil improvement curing agent comprises the following components based on 100 parts of total mass: 60-70 parts of an adhesive; 10 to 15 parts of a diluent; 2-3 parts of a coupling agent; 1-2 parts of a toughening agent; 0.1 to 0.5 part of a defoaming agent; 1-2 parts of an emulsifier; 1-2 parts of a water reducing agent; and the balance of deionized water. The soil stabilizer is an organic polymer composite soil stabilizer capable of forming a cross-linked network structure. The soil stabilizer disclosed by the invention has the characteristics of low pollution, good soil solidification performance, rich application scenes, good dispersion effect and the like, and the defoaming agent in the soil stabilizer can effectively eliminate bubbles generated in soil solidification, so that multiple pores of solidified soil are avoided, and the soil bonding and solidification effects are enhanced; the curing agent is especially suitable for a soil body with high water content and large particle size.

This invention discloses a secure alignment method and system for large language models based on multilingual self-distillation, belonging to the fields of artificial intelligence and natural language processing. The method instantiates a teacher model and a student model from the same large language model. The student model only receives queries in the target low-resource language, while the teacher model additionally receives English queries and thought chain instructions to stimulate secure reasoning capabilities in high-resource languages. A dual-perspective security weighting mechanism is proposed to jointly evaluate teacher confidence and student deviation, adaptively adjusting the token-level penalty weight. It supports both online and offline self-distillation modes, achieving cross-language security capability transfer through weighted KL divergence optimization. This invention requires no response data and achieves superior security performance on multiple large language models and multilingual jailbreaking benchmarks, particularly demonstrating strong generalization ability on low-resource languages ​​not seen in the training set, while maintaining model versatility and eliminating the problem of existing methods relying on high-cost response data generation.

The present invention discloses a device for adhesively connecting a composite material circular tube and a closed-cell foam core material, comprising: a thickness gauge, which is axially movably arranged in the composite material circular tube, and one end of the thickness gauge is provided with a first through hole, and the other end is provided with an open accommodating cavity connected to the first through hole; wherein the closed-cell foam core material is arranged in the open accommodating cavity; an upper pressure head, one end of which is movably arranged in the open accommodating cavity and abuts against one end of the closed-cell foam core material, and the other end passes through the first through hole; a lower pressure head, which is engaged in the composite material circular tube and abuts against the other end of the thickness gauge; a one-way valve, which is arranged at the axis of the lower pressure head and is used to inject glue into the thickness gauge. The present invention also discloses a method for adhesively connecting a composite material circular tube and a closed-cell foam core material, and the thickness of the glue layer is made as uniform as possible by controlling the rotational withdrawal speed and the injection speed of the thickness gauge.

The utility model relates to a particle material fluidization pickling device capable of removing foam in a vacuumizing mode, which comprises a pickling tank, a detachable upper cover is arranged at the top of the pickling tank, the bottom of the pickling tank is of a porous structure, and the bottom of the pickling tank is connected with an acid liquor buffer cavity in a sealing mode. A circle of overflow groove is formed in the inner edge, in contact with the top of the pickling tank, of the upper cover, and the overflow groove is connected with the acid liquor buffer cavity through a return pipeline; a foam suction device is further connected into the upper cover and comprises a suction inlet formed in the upper cover and vacuum suction equipment arranged outside the upper cover. The device has the beneficial effects that by additionally arranging the foam suction pipe, the vacuum filtering tank and the vacuum suction equipment, foam can be sucked into the vacuum filtering tank to be treated in a vacuumizing mode, so that the foam generated in the pickling process is eliminated, and normal pickling operation is prevented from being influenced.

The invention relates to the technical field of polymer composite materials, in particular to a high-strength and high-toughness PHA plant fiber composite material and a preparation method thereof. The high-strength and high-toughness PHA plant fiber composite material comprises the following raw materials in parts by mass: 60-80 parts of polyhydroxyalkanoate, 20-30 parts of modified palm fibers, 1-5 parts of a plasticizer and 2-4 parts of a nucleating agent, and the modified palm fibers are long-chain fatty acid modified palm fibers. The PHA plant fiber composite material provided by the invention has excellent strength and toughness, also has excellent ultraviolet resistance, and also maintains excellent degradability of the PHA plant fiber composite material.

The utility model discloses a cargo station ground joint cutting structure which comprises a structural floor slab, the structural floor slab is provided with a plurality of parallel structural floor slab through joints in the longitudinal direction and the transverse direction respectively, a plurality of induced cracks are formed between every two adjacent structural floor slab through joints, and the structural floor slab on the wall side is provided with a linear through joint parallel to the trend of a wall. The induction cracks are partially broken, and the induction cracks are perpendicular to each other in the longitudinal direction and the transverse direction. The utility model further discloses a cargo station. According to the utility model, generation and spreading of irregular cracks can be eliminated. A relatively regular ground texture is provided and can be widely applied to the field of constructional engineering.

This invention discloses a method and system for hydrogen production using recycled PET waste and wastewater, belonging to the field of hydrogen production technology. The method involves immersing the lower half of a microreactor with a three-dimensional porous structure into an alkaline PET depolymerization solution. The alkaline PET depolymerization solution is made from PET waste, wastewater, and an alkaline catalyst. Utilizing the photothermal conversion capability of the microreactor under illumination, the solution is driven upwards to the high-temperature upper half of the microreactor, where vigorous evaporation occurs, producing water and ethylene glycol. The alkaline catalyst is concentrated, precipitated, and participates in catalysis at the evaporation interface. The mixed steam undergoes a KOH catalytic reforming reaction in the high-temperature zone of the microreactor to produce hydrogen. The water vapor is condensed and recovered, and the alkaline catalyst is directly collected. The alkaline catalyst achieves in-situ regeneration and recycling, and absorbs carbon emissions generated during the reaction, achieving zero pollution and high-purity hydrogen production. This invention achieves green energy hydrogen production and plastic degradation through an integrated design of alkaline degradation, alkaline catalysis, and alkaline recovery.

The invention relates to a casting inner runner precoated sand mud core coating and a preparation method thereof, and relates to the technical field of precoated sand casting, the casting inner runner precoated sand mud core coating comprises the following components by mass: 5-10 parts of phenolic resin, 12-15 parts of a composite binder, 3-5 parts of a dispersant, 1-2 parts of an antifoaming agent, 20-30 parts of zircon powder, 5-10 parts of a fireproof filler, and 20-30 parts of a solvent; the composite binder comprises aluminum dihydrogen phosphate and water glass. The preparation method comprises the following steps: dispersing phenolic resin into a solvent, and stirring until the phenolic resin is completely dissolved to obtain a phenolic resin solution; adding the composite binder into the phenolic resin solution, heating and stirring to obtain a binder solution; adding a dispersing agent and a defoaming agent into the binder solution, and stirring to obtain a mixed solution; and adding zircon powder and a refractory filler into the mixed solution, and stirring after ball milling to obtain the casting inner runner precoated sand core coating. The coating has the effects of improving the adhesion performance and the thermal stability, the defect rate of castings can be reduced, and the quality of the castings is improved.

The present application relates to the technical field of lead-acid battery manufacturing, and particularly relates to a lead-acid battery vacuumizing and acid-adding device, which comprises a conveying belt, an acid-adding tank, a three-way valve, an acid storage mechanism, an acid-adding pipeline, a filling mechanism, an adjusting mechanism, a vacuum system and a control system. The three-way valve core is provided with valve holes one, two and three, and a closed arc surface. The filling mechanism is provided with a sealing plunger, which blocks the filling needle head during vacuumizing and opens during acid injection. After the vacuum system vacuums the battery, the acid storage mechanism injects pre-stored quantitative acid into the battery under negative pressure. The lead-acid battery vacuumizing and acid-adding device realizes accurate control of acid quantity, elimination of bubbles and automatic continuous production, and has the advantages of high acid-adding precision, high efficiency and good battery consistency.

The invention discloses an encryption method and device for stable-control high-real-time 2M communication. The encryption method comprises the steps that a sending end and a receiving end of 2M communication construct the same random key generation module; the sending end generates timestamps according to the synchronous clock and sends the timestamps to the receiving end, and the two ends generate seed signals based on the timestamps to serve as the initial state of the key generation module; the sending end encrypts a message by using a key output by the key generation module, and the receiving end decrypts the message by using the output key; and in a key generation module state updating stage, the sending end randomly generates an updating sequence number and sends the updating sequence number to the receiving end in a hidden manner, and when the frame sequence of messages processed by the two ends reaches the updating sequence number, the state of the random seed signal updating module associated with the stability control service is synchronously updated. According to the invention, the FPGA is utilized to construct the key generation module to encrypt and decrypt the message, the time overhead is low, and the high real-time requirement of stable control 2M communication is met; and the module state is randomly updated, the periodicity of key generation is eliminated, and the encryption security is greatly enhanced.

A display device and a method of manufacturing the same are provided. A display device according to an embodiment includes: an auxiliary electrode on a substrate and transmitting a common voltage; an insulating layer on the auxiliary electrode; a light emitting layer on the insulating layer; and a common electrode on the light emitting layer, the insulating layer having a through opening disposed over the auxiliary electrode, the light emitting layer disposed over the auxiliary electrode and having a light emitting layer opening overlapping the through opening, and the common electrode being electrically connected to the auxiliary electrode through the light emitting layer opening.

The defoaming device comprises a stirring barrel, a motor is arranged at the top of the stirring barrel, a rotating shaft is arranged on the motor, the rotating shaft extends into the stirring barrel, stirring blades are arranged on the rotating shaft, the bottoms of the stirring blades are rotationally connected with defoaming rods, a feeding port is formed in the top of the stirring barrel, and a discharging port is formed in the top of the stirring barrel. A defoaming device is arranged in the stirring barrel, and a discharge hole is formed in one side of the bottom of the stirring barrel. The defoaming device for the emulsifying machine is simple in structure and convenient to use, bubbles generated in the stirring or homogenizing process can be eliminated by arranging the defoaming device, and the working efficiency is improved.

This application belongs to the field of battery technology and discloses a method for etching the copper seed layer of a copper-grid heterojunction solar cell, an etching solution, and its application. The etching solution consists of dilute sulfuric acid solution, ozone, and water, with the concentration of the dilute sulfuric acid solution being 0.6%-10% and the ozone concentration being 10-30 ppm. The solar cell containing the copper seed layer or the silicon wafer of a heterojunction solar cell containing an ITO film is completely immersed in the etching solution and etched at room temperature to remove the copper seed layer from the surface of the silicon wafer. The etching solution described in this technical solution is used to remove the copper seed layer in copper-grid heterojunction solar cells. It has a simple composition, and the waste liquid after etching is a copper sulfate solution with no harmful byproducts, making it environmentally friendly. The ozone is generated on-site from air or oxygen, and the sulfuric acid concentration is extremely low, reducing the cost of chemical solutions by more than 60% and resulting in extremely low overall operating costs. This system causes very little damage to transparent conductive films such as ITO and SnO2, and the sheet resistance and film thickness change rate can be controlled within 3%, ensuring the performance of the solar cell. Compared with other oxidant etching solutions, it avoids the etching capacity decay defects caused by oxidant decomposition.

This utility model relates to the field of pretreatment filtration components for pure water systems, and discloses an anti-clogging pretreatment filtration component for pure water systems. The component includes a housing, with a top cover fixedly connected to the top outer wall of the housing via a flange. A motor is fixedly connected to the top outer wall of the top cover, and a rotating shaft is fixedly connected to the output end of the motor. An agitator is fixedly connected to the outer wall of the rotating shaft, and a brush and a scraper are fixedly connected to the outer wall of the agitator. In this utility model, by incorporating a brush and a scraper within the component, adhesive substances and fibrous impurities adhering to the surface of the filter screen and the inner wall of the filter housing can be physically scraped and cleaned in real time. Simultaneously, the addition of an ultrasonic transmitter effectively eliminates air bubbles generated during raw water filtration, preventing the formation of an air film that obstructs water flow and accelerating the speed at which water passes through the inner filter housing. This reduces the frequency of downtime for cleaning the filter screen and improves overall filtration efficiency.

The present application relates to the corrosion protection field of sulfide treatment device, and particularly relates to a sulfide treatment device shutdown corrosion protection method and system, the method comprises the following steps: in the conversion absorption system cooling stage of the sulfide treatment device, when the first absorption tower inlet temperature of the conversion absorption system is reduced to a preset first safety temperature, at least part of the acid circulation of the conversion absorption system is stopped; hot air at a preset second safety temperature is introduced into the conversion absorption system for replacement, the residual acidic substances in the conversion absorption system are evaporated by the hot air and transported to a tail gas treatment unit; the replacement is continuously performed until the converter temperature in the conversion absorption system is lower than a preset third safety temperature, and then the replacement is stopped; the method provided by the present application has the advantages of effectively removing the residual acidic substances in the system, preventing the formation of condensed acid and acid sludge, reducing the corrosion risk of equipment, prolonging the service life of key components, and improving the safety of maintenance.

The invention relates to an integrated assembly and synchronous construction method for a cast-in-place concrete structure and a prefabricated partition wall. The method comprises the following steps: assembling ALC wallboards into a whole indoor partition wall body; (2) building an interlayer inner support frame and binding wall and column steel bars; (3) outer side formworks of the shear wall and the structural column are manufactured and installed; (4) manufacturing and installing a beam plate formwork on the upper layer and a supporting system of the beam plate formwork; (5) steel bars of the upper layer of beam slab are manufactured and installed; (6) concrete pouring is conducted on surface layers, beam slabs and local reverse ridges of the shear walls and the structural columns; and 7) removing the formwork when the concrete reaches the designed strength, and constructing the upper floor. The construction method can reduce and even eliminate the occupation of the procedure on the construction key line, and can avoid the damage to the ALC wall body during the installation of the ALC wall body; by means of the construction method, a large amount of construction waste generated in the building in the ALC plate wall construction can be reduced and even eliminated, conditions are created for use of large hoisting equipment, and the use efficiency of a tower crane is improved.

The invention provides a small electromagnetic pulse generation device, which comprises a pulse power supply module and a pulse generation module, the pulse power supply module comprises a pulse capacitor and a first switch, and the pulse generation module comprises a C02 phase change unit, a C02 liquid storage pipe, a stator coil, an armature, a second switch, a shell and a load; the side, close to the interior, of the stator coil is sequentially connected with the armature and the CO2 liquid storage pipe in a sleeved mode, one end of the CO2 liquid storage pipe is connected with the CO2 phase change unit, the side, close to the exterior, of the stator coil is connected with the shell in a sleeved mode, the space between the armature and the shell is filled with foamed plastic, and the load is connected with the exterior of the shell. The pulse capacitor is connected in series with the first switch, the stator coil, the armature and the load, and the second switch is connected in parallel with the pulse capacitor and the first switch. According to the unmanned aerial vehicle, harmful gas generated by explosive explosion and combustion and other attached damage effects are eliminated, the structure is simple, the size is smaller, unmanned aerial vehicle mounting is facilitated, and convenience is provided for control and transportation in the police process.

The invention relates to a cleaning solution for a copper surface of a ceramic-based printed circuit board and an application method of the cleaning solution, relates to the technical field of cleaning of ceramic-based printed circuit boards, and aims to solve the problem of poor appearance of'white spots' or'white dots' caused by bubble attachment at a grain boundary during traditional micro-etching cleaning of a large-grain copper layer generated by an active metal brazing process. The cleaning solution is prepared by mixing an oil removing agent and a micro-etching agent according to a specific volume ratio; the application method of the mixed cleaning solution comprises the following steps: adding pure water into a clean cleaning tank, adding the oil removal liquid and the micro-etching liquid according to a preset proportion, supplementing the pure water to a working liquid level, circularly heating to a set temperature, and immersing a ceramic-based printed circuit board to be treated into the mixed cleaning solution for treatment; according to the method, oil removal and micro-etching processes which are carried out step by step in a traditional production line are integrated into one step, and aggregation and attachment of micro-etching reaction bubbles on a copper surface grain boundary and holes are effectively inhibited by utilizing the synergistic effect of components in the mixed solution, so that the phenomenon of'white spots' is eliminated from the source.

The invention relates to a pressurized curing device and method.The pressurized curing device comprises a first hollow cylinder structure and a second hollow cylinder structure which are connected with each other, and the second cylinder structure is arranged in the first cylinder structure; a through hole is formed in the bottom of the second cylinder structure, a clamping groove is formed by the bottom of the second cylinder structure and the bottom of the first cylinder structure, a micropore fixing plate is arranged on the clamping groove in a clamping mode, and the micropore fixing plate is provided with a plurality of micropores. According to the invention, the curing process between the wave shift optical fiber and the microporous plate is carried out by applying the positive pressure, so that the curing structural strength of the microporous fixing plate is improved.

This invention relates to a method for the electrocatalytic oxidation of anisole to anisole sulfoxide using iron-based complexes, belonging to the fields of homogeneous catalysts and electrocatalytic oxidation technology. The invention utilizes an iron-based complex formed by coordination between a tetraamide macrocyclic ligand (TAML-H4) and metallic iron as a homogeneous molecular catalyst, with water as the sole oxygen source, to construct an electrocatalytic anisole oxidation system. Through the synergistic effect of the catalyst and water, a proton-coupled electron transfer and single-electron oxidation process occurs at the anolyte, resulting in the loss of two electrons and two protons to generate a high-valence iron-oxygen active intermediate [Fe]. Ⅴ (O)(TAML)] – This invention achieves highly efficient and selective oxidation of anisole, generating the high-value-added product benzyl sulfoxide at the anode. It eliminates the need for additional strong oxidants, employs mild reaction conditions, boasts high atom economy, and is environmentally friendly, making it suitable for the green conversion of sulfides in the synthesis of fine chemicals. This provides a feasible pathway for the industrial production of sulfoxide compounds.

The invention discloses a method for treating sulfide in a silicon-manganese alloy slag leaching process. The method comprises the following steps: mixing the silicon-manganese slag and the anode slag in the electrolytic manganese production process according to a ratio, and pressing the mixture into powder by using a roller press. Then, anolyte generated in the electrolytic manganese production process is used for pulping leaching reaction, 93% concentrated sulfuric acid is added after the reaction is carried out for 1 hour, and then the reaction is carried out for 1-2 hours; finally, the slurry is conveyed to a filter pressing section for treatment, filtrate is recycled, and filter residues are transferred to a residue field for stockpiling pretreatment. The method has the beneficial effect that the resource waste is effectively reduced by recovering the manganese element in the silicon-manganese slag and the anode slag to the maximum extent. By eliminating hydrogen sulfide gas, the risk of environmental pollution is reduced, and the environmental protection requirement is met. Meanwhile, the waste treatment process is optimized, the overall treatment efficiency and economic benefits are improved, and the sustainable development concept is supported.

The present invention relates to a mining manual unloading device for steel strands, comprising a plurality of groups of unloading frames, which are connected end to end, each group of unloading frames is provided with a working support and an I-beam, and the I-beam is arranged on the top of the working support, adjacent working supports and I-beams are connected and fixed by a plurality of first connecting plates, an L-shaped steel is arranged on one side of the I-beam, adjacent L-shaped steels are connected end to end by a plurality of second connecting plates, a transmission plate is arranged on one side of the L-shaped steel, the transmission plate is installed on the top of one side of the I-beam through a hinge, the I-beam and the working support are connected by a supporting plate, the supporting plate located on one side of the unloading frame as a whole extends out of the I-beam, and a limiting frame for limiting the steel strand is installed on the supporting plate, a material guide handle is fixedly connected to the other side of the L-shaped steel close to the limiting frame, and a switch assembly for fixing the length of the steel strand is arranged on the inner side of the L-shaped steel, so that it can be safely applied to dangerous areas such as underground coal mines.

The present invention discloses a method for producing an EPS foam relief mural building component, and relates to the technical field of building components. The present invention comprises a polystyrene insulation board, a polymer mortar and a base, wherein the polymer mortar is arranged below the polystyrene insulation board, and the base is movably connected to the side of the polymer mortar away from the polystyrene insulation board, and the position of the base on the polymer mortar does not exceed the height of the polystyrene insulation board. The present invention solves the problems of inconvenient transportation of the original parts of the existing relief components, cumbersome handling, long installation and construction period, large manpower and material resources, and red bricks are not easy to decompose and weather, and occupy a large area, through alkali-resistant glass fiber grids, foam glass insulation boards, friction pads, and bases; the shortcomings of cement components are low tensile strength, poor ability to resist deformation, easy cracking and brittle failure, too heavy deadweight and volume, easy to produce cracks, missing edges, falling corners, rough surfaces, honeycombs, and other common quality problems.