Investigation Of The Strength Of Mortar At Cryogenic Temperatures
Abstract Jiang Zhengwu Et al. reported a paper on increased strength and various mechanisms for mortars at cryogenic temperature. In this paper, the strength of mortar at cryogenic temperatures was experimentally studied and empirical model was prepared. The relationship between the increased cryogenic strength and pore ice formation was studied. From the experiment performed, the result obtained have flexural strength was increased up to two times, which is higher compared to compressive strength. The paper produced by Sezer Morkavuk Et al. was about carbon fiber reinforced plastics and effect of cryogenic temperature on tensile properties. The main intension of this study is to investigate the milling performance of carbon fiber reinforced plastics in cryogenic medium. The result obtained reviews that cryogenic machining approach results in less damage to the machined surface and improves tensile properties of carbon fiber reinforced plastics. Junhui Liu Et al. presented a paper on degumming of hemp fiber by the application of cryogenic and mechanical treatment. As natural fiber reinforced composite usage is restricted in industrial applications, new degumming method was suggested in this paper. The cryogenic and mechanical treatment was performed on hemp fiber to make them loose and the result obtained increases cellulose content and decreases diameter of hemp fiber. The paper presented by R G Deshpande and K A Venugopal is based on machining with cutting tool which is cryogenically treated, the main intension of this study is to bring a change in machining process and controlling various parameters associated with it. This is achieved by exposing the metals to temperatures below -180°C. The result obtained reveals increase in tool life and wear resistance. Yikun Zhang Et al. presented a paper on cryogenic magnetic properties in the pyrochlore compounds.
The main pyrochlore compounds were synthesized by ceramic method and their crystal structure was also determined. Magnetism in some heavy rare-earth [RE] based oxides have superior physical and chemical properties. This pyrochlore was fabricated and their properties were tested, the result values of RE2TiMn07 compounds shows that these compounds are potential candidates for MR application for helium liquification.
Kang Zhu ET al. produced a paper on cryogenic tank which discuss about the thermal stress and cool down performance influenced by filling methods. Experiment was performed to check thermal stress and cool down performance in aluminum tank and stress was checked at different levels. It was observed that the wall temperature in the circumferential direction was less uniform than those during top nozzle filling. Marcello Cabibbo presented a paper on zinc oxide nanowires which are cryotreated. The mechanical properties of nanowires are detected by Nano indentation test. After deep cryotreatment, young’s modulus of bulk base zinc oxide nanowires was halved. Ricardo I Amils Et al. presented a paper which insist the use of cryogenic low noise amplifier technology in many fields. In this application epoxy plays an important role due to its excellent thermal conductivity. A prototype was prepared which mimics the practical use of this cryogenic device. The result reviews that by lowering temperature, low noise amplification can achieve better noise performance. A paper about compact cryogenic pump was presented by Gang Li and Shane Caldwell.
The main intension of this study to design a pump which can circulate liquid nitrogen at 2-10 L/min into a head of 0. 5-3 mtr. The designed pump solved the problem of boiling and cavitation. Jia-Bao Yan and Jian Xie presented paper which involves experimental studies on mechanical properties of steel reinforcements under cryogenic temperature. This paper includes the experimental study on different type of reinforcing steel that is used in the liquefied natural gas containers and in reinforced concrete structure. It was observed that the effect of cryogenic temperature on steel, changes its mechanical properties. Hence more future work can be performed on fracture behavior of these steels. Shaohong Li Et al. present a paper which discusses about the stainless-steel bearing during aging. It was observed that hardness of stainless steel is enhanced after cryogenic treatment, it is mainly due to transformation of austenite to martensite crystal structure at low temperature. The result indicates that the cryogenic treatment increases the diffusion driving force of atoms. Zdenek Slanina Et al. presented a long-term experiment on cryogenic chamber. The main reason of this study is to design and construct a device with proper sensors which can perform in extreme environmental conditions and transmit the data into computer. Special drivers were used during experiment like Bluetooth technology. Finally, the sensors are capable of working more than ten hours in cryogenic chamber.
D S Nadig Et al. presented paper about performance of integral diaphragm press transducers for space application through cryogenic treatment. The main intension of this study is to avoid internal stress on transducers which were produced during machining. To overcome this, machined transducers are hence cryotreated resulting in increase of its dimensional stability and linearity. R Thornton Et al. studied about the effect of cryogenic processing on wear resistance of grey cast iron brake disc. Cryogenic treatment is an inexpensive treatment which has an ability to affect the cross section of component. By using cryogenic treatment on grey cast iron brake rotors wear resistance is improved. Thus, there is no change in hardness or roughness. Xiaoguang Wu Et al. experimented on coal breaking with cryogenic nitrogen jet. The main intension of this jet is to avoid the leakage of drilling fluid and avoid reservoir damage which was caused due to solid and water invasion. To avoid this Coal bed methane drilling was implemented with cryogenic nitrogen jet. The result reveals that nitrogen jet can create large erosion depth ranging from 5Mpa to 15Mpa.
The vast field of cryogenics deals with the temperatures below -150°C and its applications. In almost all fields of science and technology making its influence crucial. The various applications of cryogenics are to be evaluated and properly utilized to make advancements that can fetch better results in studying, processing and manufacturing hence yielding better efficiency and productivity. The increase in cryogenic strength is more due to formation of pore ice. The cryogenic temperature of cement-based material is quite different from those at room temperature. The LNG is usually stored in a concrete tank which is made up of steel and concrete. Cryogenic machining is used to machine carbon fiber reinforced plastics usually automobile interiors are made up of natural fiber reinforced composites. The carbon fiber reinforced plastics at a macro size is a combination of plastic matrix and carbon fiber reinforcements. This carbon fiber reinforced plastics are abrasive, anisotropic and have low thermal conductivity in nature. Cryogenic machining is an alternative for conventional machining, the main intention of cryogenic machining is to remove the heat generated. The cryogenic treatment is performed on hemp fiber bundles, which makes it loose after treatment. The special property of hemp fiber is that it has an ability to absorb sound and is cost effective. Near infrared spectrometer was used to examine the change in components of hemp fiber. The chemical and thermal changes in hemp fiber is examined in Fourier transform infrared and thermogravimetric analysis. The cryogenic treatment was carried out on cutting tool to enhance its properties to avoid tool failure during cutting. The retained austenite was converted to martensite during cryogenic treatment, this results in increase of tool life. The magnetic refrigeration is most popular as it is environmentally friendly as it’s based on magnetocaloric effect R2M2O7 pyrochlore compounds which is crystallized in cubic and monoclinic structure, which had a wide range of ordered magnetic structure.
The storage and delivery of the cryogenic fluid is important in civil and aerospace engineering. This may lead to many problems which may lead to thermal stress within the wall of the tank. For this purpose, comprehensive study is required to establish the required connection between the flow temperature field and thermal field. Zinc oxide is a good semiconductor and hence has piezoelectric properties, the zinc oxide nanowires have various application in microelectronics. Using the indentation method, the elastic properties and hardness of zinc oxide nanowires is measured. Microscopic inspections were performed using field emission scanning electron microscope. The radio astronomy and certain deep space communication requires low noise performance, this is performed using low noise amplifiers with InP or GaAs high electron mobility transistors that are cooled at cryogenic temperature. The monolithic GaAs chip is attached to chassis using epoxy. To avoid various problems this, noise source consisting of microwave termination at a known and controlled cryogenic temperature is used.
As cryogenic cooling is achieved using a cryogenic fluid like liquid nitrogen this fluid comes in direct contact with apparatus when continuous liquid nitrogen is required the excess fluid is simply discarded. To avoid this liquid nitrogen is used, while designing of liquid nitrogen pump several parameters are to be considered like temperature, lubrication, boiling, cavitation and specific speed. The liquified natural gas is stored in containers which is made up of steel and concrete. The fluid comes directly in contact with container which is made up of several layers of steel. The hot rolled or the cold formed mild steel reinforcements is used in liquified natural gas to increase its mechanical properties. Bearings are widely used, they are subjected to stresses and bending moments. The conventional hardened bearing is not suitable for aero space applications. The micro structure of bearing contains two types of carbides which place a major role in life and performance of bearing. After hardening remained autunite tend to transform into brittle martensite during service due to stresses. Thus, cryogenic treatment is performed on steel to improve its mechanical properties.
Cryotherapy is an extreme cold treatment method which includes the application of dry deep-freezing on the outer surface of human body for about 2-4 minutes it helps in increasing of mobility in the affected limbs and effective against pain and performed in cryogenic chambers. The integral diaphragm pressure transducers are used to measure pressure on space craft and in launch vehicles, the machined diaphragm with bonded strain gauge is used. The condition of diaphragm is decided by heat treatment process which includes stress relieving and stabilizing process. Disc brakes are one which produces repetitive uniform response with long shelf life. It represents a complex tribosystem and the brake pads are made of composites materials like friction rings that must be cryotreated to withstand harsh conditions like temperatures of 700°C. By the usage of Coal bed methane well bore collapse occurs. This is due to low strength of coal.
So, drilling with cryogenic nitrogen jet is implemented where no reservoir damage occurs. Summary In the following literature review we have studied and inferred from various cryogenic experiments and studies. This review indicates the vast influence on human life and day to day activities, from medical treatments to sophisticated precision machining. Cryogenics hence helps abilities of various materials processes and treatments to advance and yield to its full potential by using viable means. From cryogenic treatment the strength of mortars increased up to two times. Along with this water content and room temperature were the important factors effecting the cryogenic temperature. The tensile and elastic modulus of cryogenic treated carbon fiber reinforce plastic is observed to be enhanced by 3. 65% and 3. 04% respectively. The less damage was observed in cryogenic machining than dry machining. The increase in Thermal stability of hemp fiber is observed when it is cryogenically treated. Hence thermal stability is higher compared to untreated fibers. Cryogenic treatment has its effect on tool life. The cryo treated tool has high hardness and bond strength, which Increases the tool life. From the cryogenic magnetic properties, it was observed that the chemical composition of Dy2TiMno7 and HO2TiMno7 are nearer to the nominal composition of 2: 1: 1: 7.
In the study of cryogenic tank, it was observed that the tank had increased its cooling rate and the wall temperature in the circumferential direction were less uniform than those during top nozzle filling method. The cryogenic treatment of zinc oxide nanowires does not affect youngs modulus nor the critical buckling load, stress and strain to greater extend. The experimental data shows a large thermal conductivity difference between GaAS semiconductor and epoxy in noise sources chip by lowering temperature, LAN can achieve better noise performance. The designing of cryogenic pump had solved the problem of boiling and cavitation with the pump, hence the designed pump can deliver liquid nitrogen into 2m head at different flow rates.
The study of properties of steel reinforcement under cryogenic temperature reveals that as the temperature decreases the yield and ultimate strength increases and fracture strain was observed as temperature decreases. The typical cryogenic treated cycle was used on transducers to reduce the residual stresses by 55-60% due to the transformation of retained austenite into martensite, this type of change will enhance the long-term stability of transducers. The cryogenic treatment on grey cast iron which were used in brake rotors results in improvement of Wear resistance without change in hardness or roughness. By using cryogenic nitrogen jet, large erosion depth can be created from 5MPa to 15MPa.
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