44results about How to "Frame structure is stable" patented technology

The invention discloses a double-layer coated core-shell negative electrode material for lithium ion battery and a preparation method thereof. A CVD deposition method is used for depositing nano silicon on that graphite particle to obtain a precursor of a negative electrode material; The titanium dioxide, the lithium carbonate and the organic pyrolysis carbon source are dispersed in an organic solvent to prepare a gel; the precursor of anode material was added into the gel, and the core-shell structure anode material was prepared by low temperature treatment, homogeneous dispersion and high temperature reaction. The core of double-layer coated core-shell negative electrode material for the lithium ion battery is nano silicon and graphite, the nano silicon is deposited on the surface of graphite particles, the outer shell is an organic pyrolytic carbon layer, and the inner shell is formed by attaching lithium titanate to the inner wall of the organic pyrolytic carbon layer. The core-shell negative electrode material has high capacity, high rate and excellent cycling performance, and the preparation process is simple, green and pollution-free, suitable for large-scale production.

The invention relates to a negative electrode material of a lithium ion battery and a preparation method thereof, and relates to a lithium ion battery. The invention provides a negative electrode material, which is low in preparation temperature, small in energy consumption, simple in operating process and better in electrochemical performance, of a lithium ion battery and a preparation method thereof. A chemical general formula of the negative electrode material of the lithium ion battery is Zn3-3xM3xV2O7(OH)2(H2O)2, wherein M is Fe, Co, Ni, Cu and Mn, and x is not less than 0 or not more than 0.20. The preparation method comprises the following steps: 1, weighing a zinc-containing reagent, a zinc and vanadium-containing reagent and a corresponding doping ion reagent according to the stoichiometric ratio of the chemical general formula of Zn3-3xM3xV2O7(OH)2(H2O)2, and mixing to obtain a chemical reagent; 2, ultrasonically dispersing the chemical reagent obtained in the step 1 by using deionized water which is equivalent to 444-666 times of the mole ratio of the chemical reagent obtained in the step 1 to obtain a suspension; 3, reacting the suspension obtained in the step 2 in a reaction kettle to prepare the lithium ion battery negative electrode material.

The invention discloses a low-temperature denitration catalyst based on a metal organic framework structure and a preparation method of the low-temperature denitration catalyst. The catalyst comprisesa carrier and an active component attached to the carrier, the carrier structure is a metal organic framework structure MOF-74, the active components are manganese and metal X, and X is one or more of copper, iron, cobalt, nickel, zinc and magnesium. The low-temperature denitration catalyst based on a metal organic framework structure has the advantages of large specific surface area, high porosity, a stable frame structure, complete exposure of metal active points and the like; the MOF-based low-temperature efficient denitration catalyst has the advantages that the catalytic efficiency at 150 DEG C is close to 100%, the active temperature window is wide, the application prospect is promising, the reaction activity in the low-temperature range is excellent, the toxicity is avoided, the safety is realized, and the production cost is low.

A preparation method of a spherical lithium ion battery anode material vanadium borate includes following steps: (1) dissolving a vanadium source, a boron source and a reduction agent in deionized water to obtain a mixed solution according to the molar ratio of vanadium element, boron element to the reduction agent of 1:1:2-4; (2) placing the mixed solution in a 60-90 DEG C constant-temperature water-bath pot with stirring for 4-8 h to obtain a solution; (3) regulating the pH of the solution to 6-9; (4) performing granulation to obtain a vanadium borate precursor in a spray-drying manner; (5) placing the vanadium borate precursor in a tubular sintering furnace and sintering the vanadium borate precursor at 500-800 DEG C for 8-20 h under a non-reducing atmosphere. The spherical lithium ion battery anode material vanadium borate is high in specific capacity, is excellent in rate capability and is excellent in cycle performance due to the unique crystal structure and micro appearance of the material.

An integrated binding and locating device of single-box double-chamber full span box girder reinforcing steel bar comprises two lines of inner tire frames disposed on ground longitudinally; the device is characterized in that each line of inner tire frames comprises two lines of longitudinally distributed tubular fixing piles, supporting legs inserted between the two lines of tubular fixing piles, two lines of longitudinal platforms fixedly disposed on the supporting legs, two lines of longitudinal chutes detachably connected to upper surfaces of two lines of platforms, and a line of supporting frames disposed on the two lines of chutes; the side walls of the chutes are provided with location holes; the supporting frame comprises four vertical rods with adjustable heights, connecting rods connected between two adjacent vertical rods, pulleys connected to the lower ends of the four vertical rods, and #-shaped frameworks fixedly connected to upper ends of four rods. The device is a reinforcing steel bar binding auxiliary tool which enables the integrated binding of single-box double-chamber box girder to be faster, the location thereof to be more precise, and the assembling and disassembling thereof to be simpler; and the device has the advantages of simple operation, exact location and high working efficiency.

The invention discloses a high-strength aviation impact-resistant anti-vibration shielding cabinet, and relates to the technical field of aviation shielding cabinet equipment. The cabinet comprises two parallel side plates (1) and a rectangular frame (2), and the rectangular frame (2) is installed between the two parallel side plates (1) in a parallel manner. The rectangular frame (2) comprises a sealing cross beam (3) and a reinforcing vertical beam (4), which are connected through a riveting block to form the rectangular frame (2). The sealing cross beam (3) comprises a cross beam main body (31), and the cross beam main body (31) is provided with a circular bottom hole (32) for installing a steel wire thread sleeve, a flat hole (33) for installing a riveting block (5), a irregularly-shaped hole (34) for installing a nut bar (6), wherein the irregularly-shaped hole (34) is located at an inner side of the cross beam main body (31). The cabinet is advantageous in that the cabinet guarantees the overall strength of the cross beam main body (3) and the reinforcing vertical beam, and improves the work stability.

The invention discloses a preparation method of a core-shell structure hollow microcube SnO2-Fe2O3 sensitive material and application of a core-shell structure hollow microcube SnO2-Fe2O3 sensitive material in an acetone gas sensor. The preparation method comprises the following steps of: preparing SnO2 porous hollow microcube powder by combining a solution chemical etching method with high-temperature calcination; taking SnO2 porous hollow microcube powder as a core skeleton structure, growing Fe2O3 nanoparticles on an outer shell layer of the SnO2 porous hollow microcube powder through adoption of a hydrothermal method in combination with high-temperature calcination to prepare a core-shell structure hollow microcube SnO2-Fe2O3 sensitive materiald, wherein the acetone gas sensor is manufactured on an aluminum oxide substrate sheet printed with a gold interdigital electrode in a dropwise coating manner and is used for selectively detecting an acetone gas. The preparation method is simple and controllable, and the material is stable in structure and good in dispersity; and moreover, the sensitivity and the selectivity of the acetone gas sensor can be obviously improved.

The invention relates to a manufacturing method for a door body used for a refrigerator, the door body used for the refrigerator and the refrigerator. The manufacturing method for the door body comprises the following steps that a panel, a door lining, an upper decoration strip, a lower decoration strip and two side frames are provided; the two side frames are fixed to the two side ends of the door lining respectively; the upper decoration strip is fixed to the door lining and the upper side end of at least one side frame, and the lower decoration strip is fixed to the door lining and the lower side end of at least one side frame; the panel is glued to the upper decoration strip, the lower decoration strip and the forward surfaces of the two side frames for enabling the panel to be arranged opposite to the door lining, so that a foaming space is formed among the panel, the door lining, the upper decoration strip, the lower decoration strip and the two side frames; and foaming materials are injected into the foaming space and are subjected to foaming, so that a heat preservation and insulation layer is formed in the foaming space. The door body is made through the manufacturing method. The refrigerator comprises a refrigerator body and the door body made through the manufacturing method, and the door body is connected to the refrigerator body directly or indirectly.

The invention provides a low-carbon ecological protection system of a rock slope. The low-carbon ecological protection system of the rock slope comprises a slope surface, first degradable plates, second degradable plates, planting bags and anchor rods; the first degradable plates and the second degradable plates are intersected and vertically arranged on the slope surface; the intersected places of the first degradable plates and the second degradable plates are fixed on the slope surface through the anchor rods; the multiple first degradable plates and the multiple second degradable plates are arranged at intervals to form a netty lattice beam structure; the multiple planting bags are arranged in the lattice beam structure in a staggered manner; and surface soil is filled in the planting bags. The system is suitable for low-carbon ecological environment protection; a rock slope soil drainage system is high in drainage efficiency; the frame structure in the rock slope is more stable to excellently maintain water and soil in rock slope soil; and selected materials are environmental protecting materials without influencing the soil.

The invention relates to a corner connector (10) for rod-shaped profile elements, with a connection element (11) which comprises at least two attachment portions (20, 21) which are oriented substantially perpendicular to each other and which are each designed such that an attachment portion (20, 21) and a front end of the rod-shaped profile elements (18, 19, 39) to be connected engage in each case one inside the other, at least one transverse strut (12) of which the ends (26, 27) are designed such that an end (26, 27) of the transverse strut (12) and a connection portion (30, 31, 48, 49) provided on a lateral surface of the rod-shaped profile elements (18, 19, 39) to be connected in each case engage releasably one inside the other, and a clamping element (13) which clamps the transverse strut (12) releasably against the corner connector. The invention further relates to an assembly system composed of such corner connectors and supporting or holding frames composed of such corner connectors and profile elements.

The invention provides a novel aluminum-based metal-organic framework (MOF) material with high stability as well as a preparation method and air water absorption application thereof; the aluminum-based MOF material is a solid crystalline material with a three-dimensional network structure, the structural general formula is Al (OH) L, L is a dicarboxylic acid organic ligand of a six-membered nitrogen-containing heterocyclic ring; the MOFs material can be used as an adsorbent material to adsorb water vapor from air. In the preparation process, the N heteroatoms are introduced to an organic ligand to modify and change hydrophilic level point distribution of pores of the MOF material, so that a framework of the material is changed from flexibility to rigidity, the water absorption capacity of the material under low humidity is improved, and energy required by desorption is reduced. The material has excellent chemical stability, water stability and thermal stability; the preparation method is simple, the cost is low, and the material has great application prospects.

The invention provides a comprehensive treadmill load testing machine. The testing machine comprises a testing platform and a test control device, wherein a portal frame I is arranged on the testing platform and provided with two vertical beams, a horizontal beam and a lifting beam; bottoms of the two vertical beams are connected with the testing platform, and the horizontal beam is connected with tops of the two vertical beams; lead screws are arranged on the two vertical beams, gears are arranged at two ends of the lifting beam respectively, a pressure testing device is arranged on the lifting beam, and a motor for driving the lead screws to operate is arranged on the testing platform. The comprehensive treadmill load testing machine can test the static load of a treadmill and can test a pedal platform, a side handrail or a front handle. Besides, an operation panel can display testing results and testing data information during testing, display testing curves, edit test reports and print various results and curve reports.

The invention provides an outdoor multifunctional portable cart which comprises a supporting back frame, a supporting underframe and a foldable supporting bracket. The supporting back frame is connected with the supporting underframe through movable connecting pieces, a handle is arranged at the top of the supporting back frame, a supporting frame is further arranged on the supporting back frame and the supporting underframe and fixedly connected with the two through three-way pipe fittings via five steel pipes, stair climbing wheels are arranged at the bottom end of the supporting back frame, and a foldable seat frame is arranged in the rear of the supporting back frame. The outdoor multifunctional portable cart has the advantages that the outdoor multifunctional portable cart is of a firm frame structure, so that inconvenience in moving ahead cannot be caused by unbalance of the center of gravity when the pavement is rugged; the foldable seat frame is provided, so that a tool for rest is provided anytime and anywhere during outing, a steel plate arranged on the seat frame can bear load better, and a user cannot feel tired when sitting on the seat frame for a long time; meanwhile, the extended stair climbing wheels can bring convenience to the user for going down and going up stairs, and particularly when the user goes out for fishing, a universal umbrella rack and a fishing rack which are arranged are quite practical and convenient.

The invention relates to a metal organic framework material for selectively and rapidly removing Sr2+ in a strong alkaline solution and preparation and application thereof. The structural formula of the metal organic framework material is [(CH3)2NH2]2[ZrC6H4(CH2PO3)2F2], the metal organic framework material is named as SZ7, p-xylene diphosphate and zirconium ions form a layered structure, oxygen atoms, zirconium ions and fluorine ions in p-xylene diphosphate form a ZrO4F2 octahedron, and dimethylamine cations [(CH3) 2NH2]+ are filled in the layered structure. The invention also discloses an application of the SZ-7 as an Sr2+ adsorbent. The Zr-based MOFs material with a very stable structure is developed by utilizing the strong binding force of the phosphonic acid ligand and the Zr4+ metal center, and radioactive Sr2+ can be rapidly and selectively removed in a strong alkaline environment.

The invention discloses a CT slip ring electric brush carrier and a forming method thereof, the CT slip ring electric brush carrier comprises a CT slip ring electric brush carrier, the CT slip ring electric brush carrier comprises a carrier body and a brush holder, the carrier body is provided with a conductive channel and a brush holder mounting hole for mounting and placing the brush holder, the carrier body is composed of a phenolic resin plate and a copper plate arranged on the phenolic resin plate, and a tawny semitransparent epoxy resin layer is also arranged on the outer surface of the copper plate. According to the invention, the phenolic resin plate and the copper plate are adhered to each other to replace an existing thick copper-clad plate, so that the use of copper is reduced, and the cost is reduced.

The invention relates to the field of tools for grinding, polishing or sharpening, and discloses a feeding device for a shot blasting machine, the feeding device comprises a feeding port, an upper baffle and a lower baffle, and the lower baffle is divided into an inverting plate from the outside to the inside. The supporting mechanism is fastened in a groove to form a whole; the outer side of thefeeding port is provided with a driving mechanism for pushing the inverting plate to be turned up and down, the supporting mechanism comprises a first sliding slot and an adjusting box, the adjustingbox is provided with two relatively-disposed pistons, a first cavity is formed between the two pistons, a piston rod is fixedly connected to one side, away from the first cavity, of each piston, the free end of the piston rod is connected with a first slider matched with a first sliding g, the top of the first slider is flushed with the top of the inverting plate, the first slider is connected tothe inner wall of the feeding port through a first spring; a second platform is arranged below the feeding port, a hydraulic cylinder is arranged on the second platform, and the hydraulic cylinder isin communication with a hydraulic pipe by the first cavity. The feeding device supports the inner wall of the feeding port to avoid depressed deformation of the casing at the feeding port.

The invention relates to the technical field of light and convenient mechanically operated tools, in particular to a modular profile steel combination type machine vise. The modular profile steel combination type machine vise is provided in order to solve the problems that the existing vise is high in cost and regulating friction force is large. The machine vise comprises two sleeper tracks and afirst notch between the sleeper tracks, wherein one end of a fixed vise jaw is located through a pin and fixedly connected by a first bolt, and the horizontal position of the other end of the fixed vise jaw is fixedly connected with a baffle through a third bolt; a first axial hole is arranged in the middle of the baffle; a regulating nut is arranged between the two sleeper tracks, the two sides of the regulating nut are provided with first projections, a first screw hole is arranged in the middle of the regulating nut, the first screw hole and the first axial hole are located on the same axis, and a screw is arranged in the first screw hole through thread engagement connection; a second projection around the screw is arranged in the position close to the end part of the screw, and the diameter of the second projection is larger than the diameter of the first axial hole in the baffle; and a moving vise jaw located through a cross track and fixedly connected through a second bolt is arranged above the regulating nut.

The invention discloses a corrugated board with good stability and high strength and a production process thereof, and the corrugated board comprises the following raw materials: 25-30% of waste needle leaves, 25-30% of waste broad leaves, 10-15% of waste nylon fibers, 10-15% of waste animal fibers, 10-15% of waste paper and 5-10% of starch. The waste needle leaves are at least one of green metasequoia fallen leaves, green larch fallen leaves, green cryptomeria fortunei fallen leaves and green taxus chinensis fallen leaves. According to the corrugated board with good stability and high strength and the production process thereof, by utilizing the share of the waste needle leaves and the waste broad leaves, the waste nylon fibers, the waste animal fibers and the waste paper, production resources are saved, powerful support is provided for environment protection, meanwhile, the plant fibers, the animal fibers and the artificial fibers are used as a framework, and the production cost is reduced. And the paper pulp is supported, so that the manufactured paperboard has a stable frame structure, the pressure resistance of the paperboard is enhanced, and the repeated utilization rate of the paperboard is increased.

The invention discloses a folding locking-fixing type heightening iron pallet. The folding locking-fixing type heightening iron pallet comprises four frames which are connected end to end in sequence to form a rectangular frame and four support legs respectively connected to the end parts of two adjacent frames; a first connecting device is arranged on the bottom of each support leg, the top of each support leg is provided with a second connecting device, and the first connecting devices and the second connecting devices are used in a manner of whole set to fix two folding locking-fixing type heightening iron pallets stacked up and down. By arranging the first connecting devices and the second connecting devices which are used in a manner of whole set, two folding locking-fixing type heightening iron pallets stacked up and down can be fixedly connected, such that the upper part space of a carriage is effectively used during use of the iron pallets, and a transportation cost is reduced.

The invention discloses a fully insulated damage-resistant outdoor distribution box, relates to the technical field of distribution boxes, and solves the problem of poor anti-damage ability of the existing distribution box and the subsequent influence on normal use due to structural deformation caused by impact in outdoor use. The distribution box comprises a box body arranged on a base, A surfaceof one side of that box body is provide with an operation port, Four pillars are arranged on the four corners of the base, At that top of the four pillar, a top plate located above the box body is arrange, A cushion plate with that same height as the box body is arrange between adjacent pillars, a buffer layer made of elastic insulating material is arranged between the buffer plate and the box body, The buffer layer is provided with a plurality of through holes, the through holes are provided with buffer springs, the buffer plates corresponding to the operation openings are provided with openings, the openings on the buffer plates are fitted with doors with locks, and the surface of the struts close to one side of the buffer platesare provided with stoppers for clamping the edges of the buffer plates.

The invention provides a gas dryer and a CO2 absorbent for an infrared carbon and sulfur analyzer. High purity quartz powder, kaolin, kyanite and combustible plant powder are mixed according to a certain proportion and sintered into a carrier of a porous material; then P2O5 is infiltrated under certain conditions to obtain the gas dryer; and sodium hydroxide is infiltrated to obtain the CO2 absorbent. The gas dryer can maintain stable particle structure and will not form a vapor lock; the CO2 absorbent can maintain stable particle structure and has obvious colour rendering. A developer for the dryer is cobaltous chloride, and a developer for the CO2 absorbent is phenolphthalein.

The invention discloses a medical 3D printing frame comprising a frame body. The frame body comprises a left side frame plate, a right side frame plate and an upper side frame plate; and the lower side of the frame body is in an open state, transverse clamping grooves are further formed in the two side walls of the lower side of the frame body correspondingly, and a detachable clamping plate is mounted in the clamping grooves; and clamping heads are further arranged at the two ends of the clamping plate. According to the medical 3D printing frame, the lower side of the frame body is arranged to be of an open structure, the clamping plate with the clamping heads is mounted on the lower side, and the clamping plate is mounted in the clamping grooves so that the clamping plate is detachably mounted, and in this way, a 3D printing device is conveniently placed in the frame body; multiple sliding grooves of stratification structure are formed in the left side frame plate, the right side frame plate and the upper side frame plate, an electrical sliding block is mounted in each sliding groove, a 3D printing head is mounted on each electrical sliding block, the positions of the 3D printingheads can be controlled by controlling the positions of the electrical sliding blocks, and thus position conversion of the 3D printing heads can be well achieved; and the whole frame structure is quite stable.

The invention provides a gas dryer and a CO2 absorbent for an infrared carbon and sulfur analyzer. High purity quartz powder, kaolin, kyanite and combustible plant powder are mixed according to a certain proportion and sintered into a carrier of a porous material; then P2O5 is infiltrated under certain conditions to obtain the gas dryer; and sodium hydroxide is infiltrated to obtain the CO2 absorbent. The gas dryer can maintain stable particle structure and will not form a vapor lock; the CO2 absorbent can maintain stable particle structure and has obvious colour rendering. A developer for the dryer is cobaltous chloride, and a developer for the CO2 absorbent is phenolphthalein.

The invention relates to a method for selectively and rapidly removing Sr in strong alkaline solution 2+ Metal-organic framework materials and their preparation and applications. The structural formula of the metal organic framework material of the present invention is [(CH 3 ) 2 NH 2 ] 2 [ZrC 6 h 4 (CH 2 PO 3 ) 2 f 2 ], named SZ‑7, in which p-xylylene diphosphate and zirconium ions form a layered structure and oxygen atoms, zirconium ions and fluorine ions in p-xylylene diphosphate form ZrO 4 f 2 Octahedral, the middle of the layered structure is filled with dimethylammonium cations [(CH 3 ) 2 NH 2 ] + . The present invention also discloses SZ-7 as Sr 2+ Adsorbent application. The present invention utilizes phosphonic acid ligand and Zr 4+ The strong binding force of the metal center has developed a very stable Zr-based MOFs material, which can quickly and selectively remove radioactive Sr in a strong alkaline environment 2+ .

The invention discloses a frame structure and a prefabricated house using the same, belonging to the technical field of prefabricated houses, including a top beam, an upper corner piece, a bottom beam, a lower corner piece and a column, a top beam, an upper corner piece, and a bottom beam There are four lower corner pieces and upright columns, the upper corner piece is used to connect two adjacent top beams and upright columns; the lower corner piece is used to connect two adjacent bottom beams and upright columns; the top beam, upper corner piece, bottom beam, The lower corner pieces and the uprights cooperate to form a three-dimensional frame structure; the top beam includes an upper positioning groove, the notch of which is facing downward, and the upper positioning groove is used to fix the upper end of the side plate of the container house; the upper surface of the top beam is matched for bearing Support the roof plate of the container house; the upper positioning groove is located below the supporting surface of the top beam; the bottom beam is used to fix the lower end of the side plate of the container house and the bottom plate of the container house; the applicant aims to provide a frame The structure and the prefabricated house using it can improve the load-bearing capacity of the middle part of the frame and prevent the middle part of the prefabricated house from collapsing.

The invention relates to the field of secondary batteries, and particularly provides a crystal material, a preparation method and application thereof, a potassium ion battery positive electrode material and a potassium ion battery comprising the positive electrode material, wherein the molecular formula of the crystal material is K2M(C2O4)2, and M is at least one variable valence metal element. According to the invention, the crystal material belongs to heterogeneous isomorphism; the (C2O4)2-anion units in the crystal material are connected into a three-dimensional network structure through strong covalent bonds between C and O, and the anion units can play a role in supporting and stabilizing a crystal structure, so that the framework structure of the material is stable, potassium ions can be rapidly conducted in an open structural framework, and the ionic conductivity is high; and the crystal material can be used as a positive electrode active material of a potassium ion battery, sothat the potassium intercalation and potassium removal performances of the positive electrode active material containing the crystal material are greatly improved, and the oxidation-reduction potential and the charge-discharge capacity of the positive electrode active material are improved.

The invention discloses an inclined roadway mine transient electromagnetic interference-free transmitting device and a using method thereof. The device comprises a transient electromagnetic transmitting wire frame, a transmitting wire frame at the top of the transmitting frame and a transient electromagnetic instrument connected with the transmitting wire frame. The device is made of wood materials with good insulation and magnetism insulation, the whole structure is connected through mortise and tenon structures and bolts, no ferromagnetic materials exist, the frame body structure is stable,insulating paint is sprayed to an outer surface of the device, and waterproof, explosion-proof, insulating and anti-interference effects are achieved. By controlling the device, the device can adapt to a fluctuating slope of the roadway and adapt to the distance change between the transmitting wire frame and a top plate, the bottom plate or the head-on position of the roadway, the device can moveon a roadway track, and omni-directional electromagnetic signal transmitting and receiving of the transmitting wire frame are achieved. When a transient electromagnetic instrument system works, the transmitting device is free of human assistance and is not affected by electromagnetic interference of a human body and the support, and multifunctional control over the mine transient electromagnetic transmitting device is achieved.

The invention relates to a cooling system device, aiming at providing a cooling system bracket for construction machinery. The cooling system bracket comprises a heat exchanger mounting bracket provided with a heat exchanger mounting port; at least three heat exchanger mounting brackets are provided and installed in continous ring joint; a fan mounting bracket is positioned on the top surface of the heat exchanger bracket in ring joint and is provided with fan housing. The cooling system bracket has the beneficial effects that the cooling air cools each heat exchanger from four sides, thus ensuring lower temperature and being beneficial for heat exchange; the cooled hot air is exhausted upward from the top of the bracket, thus effectively avoiding recycle mixing of the hot air exhausted from the top and the lower cooled air; under the condition of the same cooling amount, the cooling system bracket is smaller in volume and light in weight and is convenient to maintain and replace the parts of each heat exchanger; the frame structure is stabler, thus conducing to protect each heat exchanger from damage and failure due to strenuous vibration and other exogenous actions.